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TECHNICAL ENGLISH 3 2011 USAC
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RevolucionUnattended
Technical English 3

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Estudiantes de la Facultad de Ingeniería
Conscientes del vertiginoso avance de la globalización nos damos cuenta de la
necesidad de mantener una comunicación adecuada en el comercio, industria y
mercadotecnia dentro de nuestra sociedad y considerando el desarrollo de
competencias adecuado, se ha construido un novedoso programa para contribuir a
que la Gloriosa Tricentenaria Universidad de San Carlos de Guatemala se
mantenga con ese alto nivel que la ha distinguido durante años.
Este proyecto nació a principios del año 2008 con el afán de lograr que todo
estudiante egresado de la Facultad de Ingeniería tenga conocimiento de Inglés
Técnico para poder aplicarlo tanto en sus estudios como en su desempeño
profesional.
Demostrando que hoyy siempre SOMOS LOS LIDERES de la ingeniería y pioneros
en el cumplimiento de las necesidades de formación de nuestros profesionales,
dedicamos este trabajo a todos aquellos estudiantes a quienesles interese mejorar
competentemente la aplicación de los procedimientos de ingeniería y tengan el
deseo de aprender nuevas técnicas desarrollando habilidades que constantemente
expanden la efectividad y campos de aplicación de Ingeniería. Esta primera edición
de este folleto fue creado para cumplir y llenar los requisitos del programa cuyo
objetivo es contribuir a la preparación integral para llenar de los perfiles de los
profesionales de hoy.
Logrando el cambio propuesto.
ING. MURPHY OLIMPO PAIZ RECINOS
DECANO

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Students of Engineering School
Conscious of the vertiginous advance of the globalization we realize the necessity to
maintain an adapted communication in commerce, industry and marketing
research within our society and considering the development of appropriated
competences, we have developed a novel program to contribute that the Glorious
Tricentennial University of San Carlos of Guatemala stays with that high level that
has distinguished it during years.
This project started the first semester 2008 with the eagerness to obtain that all
withdrawn students of the Faculty of Engineering have knowledge of Technical
English, becoming it a necessity that the students apply this knowledge in their
studies as in their professional performance.
Demonstrating that today and always WE ARE LEADERS of engineering, pioneers
in the fulfilment of the necessities of formation of our professionals, we present to
all students who, by their competent application of engineering procedures and
their readiness to learn new techniques and to develop skills that constantly
expand the effectiveness and fields of application of engineering. The First Edition
of this booklet was created to carry out and to fill the requirements of the program
which objective is to contribute to the integral preparation of the students in order
to fill the profiles of nowadays professionals.
Reaching goals through change
ENGR. MURPHY OLIMPO PAIZ RECINOS
DEAN

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Awareness / Acknowledgment
Information contained in this work has been obtained by gathering
information from sources believed to be reliable. However, neither
the sites or the authors guarantees the accuracy or completeness of
any information published herein and neither the Technical
Language Area not its assistants shall be responsible for any errors,
omissions, or damages arising out of use of this information. This
work is gathered with the understanding that the topics are
supplying information but are not attempting to render engineering
or other professional services. If such services are required, the
assistance of an appropriate professional should be sought.

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Contenido
LEAN MANUFACTURING ................................................................................................................................. 12
INTRODUCTION................................................................................................................................................... 12
LEAN MANUFACTURINGGOALS .............................................................................................................................. 13
STEPS TO ACHIEVE LEAN SYSTEMS........................................................................................................................... 14
DESIGN A SIMPLE MANUFACTURING SYSTEM............................................................................................................. 14
THERE IS ALWAYS ROOM FOR IMPROVEMENT............................................................................................................ 14
CONTINUOUSLY IMPROVE..................................................................................................................................... 15
MEASURE .......................................................................................................................................................... 15
HOMEWORK: ...................................................................................................................................................... 16
PROCESS DIAGRAMS ....................................................................................................................................... 17
INTRODUCTION................................................................................................................................................... 17
OPERATIONSDIAGRAM ........................................................................................................................................ 18
IMPORTANT CONSIDERATIONS................................................................................................................................. 19
PROCESSFLOWDIAGRAM ..................................................................................................................................... 19
PROCESSTRAVELDIAGRAM................................................................................................................................... 20
HOMEWORK ....................................................................................................................................................... 22
QUALITY CONTROL .......................................................................................................................................... 25
INTRODUCTION................................................................................................................................................... 25
QUALITY CONTROL CONCEPTS................................................................................................................................ 25
QUALITYASSURANCE ............................................................................................................................................ 25
MEASURING THE QUALITY..................................................................................................................................... 26
2.1 EVALUATING THE QUALITY............................................................................................................................ 26
INTRODUCINGLEAN PROCESSES ............................................................................................................................. 27
LEAN TECHNIQUES............................................................................................................................................... 27
VALUE STREAM MAPPING ...................................................................................................................................... 27
THE 5S METHOD .................................................................................................................................................. 28
RAPID IMPROVEMENT EVENTS................................................................................................................................. 28
LEAN MATERIALS ANDKANBAN ............................................................................................................................... 29
HOMEWORK ....................................................................................................................................................... 29
ALTERNATIVE ENERGY..................................................................................................................................... 32
INTRODUCTION................................................................................................................................................... 32
TODAY’S ENERGY SOURCES= FOSSIL FUELS................................................................................................................ 32
THE PROBLEMS OF THE USE OF THE FOSSIL FUELS......................................................................................................... 33
THE SOLUTIONS................................................................................................................................................... 34
SOLAR ENERGY ................................................................................................................................................ 34
SOLARHEAT ....................................................................................................................................................... 35
PHOTOVOLTAIC, OR SOLAR, CELLS .......................................................................................................................... 35
HOW SOLAR CELL ENERGY WORKS........................................................................................................................... 36

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HOW SOLAR THERMAL ENERGY WORKS.................................................................................................................... 39
WIND ENERGY ................................................................................................................................................. 41
HOW WIND POWER WORKS................................................................................................................................... 42
TYPES OFWINDTURBINES .................................................................................................................................... 43
HORIZONTALAXIS WINDTURBINES(HAWT) ........................................................................................................... 44
VERTICAL AXIS.................................................................................................................................................... 45
GEOTHERMAL ENERGY .................................................................................................................................... 47
HOMEWORK ....................................................................................................................................................... 48
BIOETHANOL PRODUCTION ............................................................................................................................ 49
WHAT ISBIOETHANOL? ........................................................................................................................................ 50
BENEFITS ........................................................................................................................................................... 50
BIOETHANOLPRODUCTION.................................................................................................................................... 51
BIOETHANOLUSAGE ............................................................................................................................................ 53
NEGATIVE SIDES OFBIOETHANOL............................................................................................................................ 55
ACTIVITIES......................................................................................................................................................... 56
REFERENCES ....................................................................................................................................................... 58
GEARS ............................................................................................................................................................. 59
BEARINGS ........................................................................................................................................................ 62
ENGINES AND MOTORS................................................................................................................................... 65
INTERNALCOMBUSTIONENGINES ........................................................................................................................... 65
BASICENGINEPARTS ........................................................................................................................................... 67
ENGINEPROBLEMS .............................................................................................................................................. 68
ELECTRIC MOTOR ............................................................................................................................................ 70
TERMINOLOGY.................................................................................................................................................... 70
DC MOTOR ........................................................................................................................................................ 71
AC MOTOR......................................................................................................................................................... 71
PARTS OF ANELECTRICMOTOR .............................................................................................................................. 71
DIGITAL ELECTRONICS ..................................................................................................................................... 72
ADVANTAGES ..................................................................................................................................................... 72
DISADVANTAGES................................................................................................................................................. 72
CONSTRUCTION................................................................................................................................................... 73
LOGICFAMILIES................................................................................................................................................... 73
RECENT DEVELOPMENTS....................................................................................................................................... 74
LOGIC GATE........................................................................................................................................................ 74
KARNAUGH MAP................................................................................................................................................. 76
PRINCIPLES OF TELECOMMUNICATIONS ......................................................................................................... 79
BASIC ELEMENTS................................................................................................................................................. 79
TELECOMMUNICATION NETWORKS.......................................................................................................................... 80
COMMUNICATION CHANNELS................................................................................................................................. 80
MODULATION..................................................................................................................................................... 80

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LEAN MANUFACTURING
Introduction
Lean manufacturing or lean
production, which is often known simply as
Lean, is a production practice that considers
the expenditure of resources for any goal other
than the creation of value for the end customer
to be wasteful, and thus a target for
elimination. Working from the perspective of
the customer who consumes a product or
service, value is defined as any action or
process that a customer would be willing to
pay for.
Basically, lean is centered around
creating more value with less work. Lean
manufacturing is a generic process
management philosophy derived mostly
from theToyota Production System (TPS)
(hence the term Toyotism is also prevalent)
and identified as Lean only in the 1990s. It is
renowned for its focus on reduction of the
srcinal Toyota seven wastes in order to
improve overall customer value, but there
are varying perspectives on how this is best
achieved.
Lean manufacturing is a variation on the theme of efficiency based on optimizing flow; it is a
present-day instance of the recurring theme in human history toward increasing efficiency,
decreasing waste, and using empirical methods to decide what matters, rather than uncritically
accepting pre-existing ideas.

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The elimination of waste is the goal of Lean, and Toyota defined three broad types of waste:
 Muda
 Mura
 Muri
Muda: is a traditional general Japanese term for an activity that is wasteful and doesn't add value or is
unproductive and it is also a key concept in the Toyota Production System (TPS).
The srcinal seven muda are:
 Transportation (moving products that is not actually required to perform the processing)
 Inventory (all components, work in process and finished product not being processed)
 Motion (people or equipment moving or walking more than is required to perform the
processing)
 Waiting (waiting for the next production step)
 Overproduction(production ahead of demand)
 Over Processing(due to poor tool or product design creating activity)
 Defects (the effort involved in inspecting for and fixing defects)
Mura: is traditional general Japanese term for unevenness, inconsistency in physical matter or human
spiritual condition.
Muri: is a Japanese term for overburden, unreasonableness or absurdity, which has become
popularized in the West by its use as a key concept in the Toyota Production System.
Lean Manufacturing Goals
The four goals of Lean manufacturing systems are to:
 Improve quality: In order to stay
competitive in today’s marketplace, a
company must understand its customers'
wants and needs and design processes to
meet their expectations and
requirements.
 Eliminate waste: Waste is any activity that
consumes time, resources, or space but
does not add any value to the product or
service. There are seven types of waste.

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 Reduce time: Reducing the time it takes to finish an activity from start to finish is one of
the most effective ways to eliminate waste and lower costs.
 Reduce total costs: To minimize cost, a company must produce only to customer demand.
Overproduction increases a company’s inventory costs due to storage needs.
Steps to achieve lean systems
The following steps should be implemented in order to create the ideal lean
manufacturing system:
1. Design a simple manufacturing system
2. Recognize that there is always room for improvement
3. Continuously improve the lean manufacturing system design
4. Measure
Design a simple manufacturing system
A fundamental principle of lean
manufacturing is demand-based flow
manufacturing. In this type of production
setting, inventory is only pulled through each
production center when it is needed to meet
a customer’s order. The benefits of this goal
include:
 Decreased cycle time
 Less inventory
 Increased productivity
 Increased capital equipment utilization
There is always room for improvement
The core of lean is founded on the concept of continuous product and process improvement and
the elimination of non-value added activities. “The Value adding activities are simply only those things
the customer is willing to pay for, everything else is waste, and should be eliminated, simplified,
reduced, or integrated”(Rizzardo, 2003). Improving the flow of material through new ideal system
layouts at the customer's required rate would reduce waste in material movement and inventory.

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Continuously improve
A continuous improvement mindset is essential to reach a company's goals. The term "continuous
improvement" means incremental improvement of products, processes, or services over time, with
the goal of reducing waste to improve workplace functionality, customer service, or product
performance (Suzaki, 1987).
Measure
A set of performance metrics which is considered to fit well in a Lean environment isoverall
equipment effectiveness, or OEE, which is a hierarchy of metrics which focus on how effectively a
manufacturing operation is utilized.
To keep things really simple, lean manufacturing has a base premise and overall goal “to get
more done with less”and this is effectively done, by:
 Minimizing inventory at and through all stages of production
 Eliminating waste
 Reducing wait times, queues
 Shortening product cycle times from raw materials to finished goods
Lean manufacturing involves some real positive, productive changes in businesses that will
have a measurable impact in the bottom line. Benefits of lean production could include:
 Reduced lead time, wait time and cycle time
 Liberated capital
 Increased profit margins
 Increased productivity
 Improved product quality
 Just in time, affordable, streamlined, cost-efficient processes, products and services
 Improved on-time shipments
 Customer satisfaction and loyalty
 Employee retention

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Homework:
Investigate the following terms related to lean manufacturing and give their definition:
 Just in time Kanban Kaizen Poka Yoke
Suggested videos:
 http://www.youtube.com/watch?v=c0Q-xaYior0&feature=related
 http://www.youtube.com/watch?v=SU01D-jTZcE&feature=related
 http://www.youtube.com/watch?v=Q89qAbAAR3Q&feature=related
 http://www.youtube.com/watch?v=ZdHGTCXcJQU&feature=related
 http://www.youtube.com/watch?v=mKb84GafalI
Activities
Complete the next chart with the next definitions:
Lean manufacturing
Reduce Time
Continuously Improve
TPS
Improve quality

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PROCESS DIAGRAMS
Introduction
The process diagrams are very important in the manufacturing industry because they give us a
clear perspective of the processes with every step, including materials, time, distance and others. This
helps the engineers to interpret and analyze the manufacturing process and make decisions that will
improve the process without being there to watch how everything works.
The diagrams are composed by three parts:
 Header
 Body
 Summary
In the header you will include all the relevant information such as: company name, analyst,
date, process, area, page number, type of diagram, etc.
In the body, you will draw the diagram that is required according the specifications of each
type and of the process.
And in the summary you will write all the steps that the process has, including time. Time is
the most important factor because we use it to calculate the process efficiency and productivity.
Example:
Header
Body
Summary

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Operations Diagram
This diagram is a graphic representation of the operations and inspections in a production
process. In this diagram we’ll include the following symbols:
Description Symbol
 Operation: is when the process has materials transformation, or
involves any action or activity for the creation of products.

Inspection: is when we check how the process is going and also
the quality of the product during the manufacturing process.
 Combined: this is an operation-inspection step and is used when
in the process you have to check the products during an
operation.
Company name: John’shouse Analyst:John Hamilton Date:Nov. 20
th
, 2010
Process:making of hot chocolate Area: kitchen Type of diagram:operations
Page 1 of 1
0.7 min
In a pot put 1 liter of water, in a stove
With high fire, let it boil
1 min
Take the 0.30 pounds of chocolate
out of the bag and put it into the pot
0.5 min 7 min
Get some marshmallows Stir frequently and let the
chocolate melt and get the
desired consistency
0.5 min
Check if the chocolate is ready
0.8 min
Get a cup and serve
0.5 min
Add the marshmallows
0.4 min
Check if it’s not too hot, Enjoy!
1
2
43
1
5
1
6

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Summary
Description Symbol # of steps Time
Operation 6 10.5
Inspection 1 0.4
Combined 1 0.5
Totals 8 11.4
Important considerations
 Note that the time is given in minutes; this is a standard for all the diagrams.
 The diagram always is going to be drawn from right to left, even if it has simultaneous
processes or not.
 The time is placed in the upper-left corner of the symbol.
 A brief description of every step of the process is written at the right side of the symbol.
 When numbering the process remember that you have to do it according to its function in the
diagram, and when you have a simultaneous process you have to write the number on the left
first and then in the right, as shown in the example.
Process Flow Diagram
The process flow diagram is a graphic representation of the steps that follows a chronologic
sequence of activities in a process or procedure, identifying them with symbols according to its
nature, and also includes all the considered important information that is needed for analysis. This
information could be distance, time, quantity, etc. This helps us discover and eliminate waste and
delays, making the process more efficient and increase the productivity in the manufacturing
industry.
In this diagram we include the storage, operation, inspection, combined, delays and
transportation symbols.
Description Symbol
 Operation: is when the process has materials transformation,
 or involves any action or activity for the creation of products.

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 Inspection: is when we check how the process is going and also the
quality of the product during the manufacturing process.
 Combined: this is an operation-inspection step and is used when in the
process you have to check the products during an operation.
 Delay: this is used when nothing is being done in the process, It could be
the wait for other paralell process to finish before adding the product to
the asembly line.
 Transportation: is when the product is moved more than 1.5
meters to the next step. This is because the human body Can move
something from one side to other between 0 and 1.5 m and its
irrelevant according to standars.
 Storage: this is used at the beginning of the process when the
materials are taken from the raw materials storage and at the end
of it in the finished product storage.
As the operations diagram, it has the same parts: header, body and summary, and it’s
important to include in the summary the time and distance that you have in the diagram.
 Time is given in minutes; this is a standard for all the diagrams.
 The diagram always is going to be drawn from right to left, even if it has simultaneous processes or not.

The time is placed in the upper-left corner of the symbol.
 The distance is written meters and in the lower-left corner of the symbol.
 When numbering the process remember that you have to do it according to its function in the diagram,
and when you have a simultaneous process you have to write the number on the left first and then in
the right, as shown in the example.
Process Travel Diagram
This diagram uses the same symbolism as the process flow and also the same structure, the only
difference is that we draw the diagram in a plan view of the manufacturing plant.
Remember to always draw the symbols in a 1 cm
2
area. This is a standard for all the diagrams that
you’re going to draw.

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 Time is given in minutes; this is a standard for all the diagrams.
 The diagram is drawn in a plan view of the manufacturing plant.
 The time is placed in the upper-left corner of the symbol.
 The distance is written in meters and the lower-left corner of the symbol.
 When numbering the process remember that you have to do it according to its function in the
diagram and the sequence in the process.
Example: (For space reasons, this diagram doesn’t include the time and distance)
Company name:Industry S.A. Analyst: John Hamilton Date:Nov 20
th
, 2010
Process:production of ketchup Area:manufacturing plant Type of diagram: process travel
Page 1 of 1

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Summary
Description Symbol # of steps Time Distance
Operation 9
Inspection 2
Combined 2
Transportation 4
Delay 3
Storage 1
Totals 21
Homework
With the given videos, draw the operations diagram, the process flow diagram and the operations
travel diagram.
 To make the operations diagram, use the following link
http://www.youtube.com/watch?v=gneZc_hafDE
 To make the process flow diagram and the process travel diagram, use the following link
http://www.youtube.com/watch?v=DkHFNnOK3Bg
 http://www.youtube.com/watch?v=TI-dSckvw0Q
 http://www.youtube.com/watch?v=a5sNItVp9cA&feature=related
 http://www.youtube.com/watch?v=9Y5Auwf0nXE
 http://www.youtube.com/watch?v=3K3-stVK0lM

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Activities:
According to the picture below, determine what symbol each operation needs:

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Complete the summary table for the diagram below:
Description Symbol No. of steps Time Description 2 Symbol No.of steps2 Time2
Tables storage
Sawing and Comprobation
Sawdust 6%
Waiting to be processed
Transfer to the pendulum
(forklift)
Transfer to the pendulum
(forklift)
Cut and Comprobation
Sawdust 0.32%
Waiting to be transported
Transfer to the assembly area
(forklift)
Transfer to the assembly area
(forklift)
Cross storage
Sawdust 0.38%
Sawdust
Cut and Comprobation
Devastation and Comprobation
Assembly and Comprobation
Sawdust and Tables.
Transfer to the Store (forklift)
Storage

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QUALITY CONTROL
Introduction
Quality control is a critical concept in every industry and profession.
As globalization continues and the world become smaller, making it possible
for consumers to pick and choose from the best products worldwide, the
survival of your job and of your company depends on your ability to produce
a quality product or service. In this chapter, we define the term “quality”,
and we introduce some important quality control concepts and methods.
For most people, quality is associated with the idea of a product or
service that is well done, looks good and does its job well. We think of a quality product as one that
lasts, holds up well under use, and doesn’t require constant repair. A quality product or service should
meet a high standard in many areas, such as form, features, fit and finish, reliability and usability.
Quality control concepts
 Costumer based: Quality is meet customer expectations.
 Statistical based:The less variation you have, the higher the quality of
your product or service.
After an organization decides on a definition of quality, you need
standards against which to measure your quality. The reason is because
many standards are driven by the desire to safeguard and well-being of
the people who use the products or services companies provide. Quality
standards are also critical in support of international trade.
Quality Assurance
Quality assurance focuses on the ability of a process to produce or deliver a quality product or
service. This method differs from quality control in that it looks at the entire process, not just the final
product. Quality control is designed to detect problems with a product or service; quality assurance
attempts to head off problems at the pass by tweaking a production process until it can produce a
quality product.

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Measuring the quality
The old manager saying: “You can’t manage what
you can measure” rings especially true in quality control.
A good measurement system helps you to know where
you’ve been and where you are going. Costumers
typically require that you measure certain attributes of
your product or service against their specifications. So,
working in quality control means that you have to
determine what to measure, how to measure it and when
to measure it.
Employee training is critical to ensure that everyone involved in your process measures the
same specifications in the same way. You also need to collect data in a usable format so that you can
analyze it to determine the effectiveness of your quality process. The effectiveness of your quality
process is directly related to the quality of your data collection and analysis process. If you don’t have
a good data, you can’t make good decisions.
2.1 Evaluating the quality
The most common way to analyze the data you collect is to use
statistics. Statistics serve many purposes within quality control:
 Statistics helps you to determine which processes or parts of processes
are causing your company the most problems (by using the 80/20 rule –
80 percent of your problems are caused by 20 percent of what you do).
 You can use statistics for sampling so that you don’t have to test 100
percent of the items you make.
 Statistics can help you spot relationships between the values you
measure – even if the relationships aren’t obvious. They also allow you to
identify small variations in your process that can lead to big problems if
you don’t correct them.
Although, much of statistics allows you to look back only at was happened in the past.
Statistical Process Control (SPC) allows you to identify problems before they can negatively impact the
quality of your product or service. The basic idea behind SPC is that if you can spot a change in a
process before it gets to the point of making bad products, you can fix the process before bad
products hits the shelves.

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Introducing Lean Processes
Lean processes are the latest diet craze in the world of quality control. Lean is a quality control
technique you can use to identify and eliminate the flab in your company’s processes. The “flab” is all
the dead weight carried by a process without adding any value.
Most company processes are wasteful in terms of time and materials, which often results in
poorer quality to the costumer – a concern of all businesses. Lean focuses in customer satisfaction
and cost reduction. Proponents of the technique believe that every step in a process is an opportunity
to make a mistake – to create a quality problem, in other words. The fewer steps you have in a
process, the fewer chances for error you create and the better the quality in your final product or
service.
You can apply the lean techniques in the following sections to all types of processes and
environments ranging from offices, to hospitals, to factories. In most cases applying lean concepts
doesn’t require an increase in capital costs – it simply reassigns people to more productive purposes
and of course, lean processes are cheaper to operate.
Lean Techniques
Value Stream Mapping
People think in images, not
in words, so giving them a picture of
how something is done is often
better than telling them about a
process. After all, the quote is
“Show me the money!” not “Tell me
about the money!”
Value Stream Mapping
visually describes a production
process in order to help workers
locate waste within it. Waste is any
activity that doesn’t add value for the customer. Typically, eliminating waste involves reducing the
amount of inventory sitting around and shortening the time it takes to deliver a product or service to
the customer upon its order.

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The 5S method
Work areas evolve along with the processes they support. As an organization implements new
actions and tools, you must find a place for them “somewhere”. Over time, clutter can slowly build as
piles of excess materials or tools grow and gradually gum up the smooth flow of work.
The 5S method is an essential tool for any quality initiative that seeks to clear up the flow of
work. The 5S describe five Japanese attributes required for a clean work place:
 Seiri (organization)
 Seiton (neatness)
 Seiso (cleaning)
 Seiketsu (standardization)
 Shitsuke (discipline)
Removing the clutter from a process eliminates
hidden inventories, frees floor space for productive
use, improves the flow of materials through the
workplace, reduces walk time, and shakes out
unnecessary items for reuse elsewhere or landfill
designation.
Rapid improvement events
No one knows a process like the workers who touch it every day. They know how the work
should flow, they can identify obstacles that slow everyone down, and they deal with problems that
never seem to go away.
A Rapid Improvement Event (RIE) is an intensive process-activity improvement, where over a
few days a company’s workers bone up on lean techniques and rebuild their processes to incorporate
its principles. The workers take apart their work areas, rearrange items and reassemble spaces for
more efficient work. The improvements are immediate, and the workers have ownership of the
process and fine motivated to further refine it.

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Lean materials and Kanban
A company’s materials are essential for the organization to work well, but they also tied up a
large part of a company’s capital. And while the company does its business year in and year out, its
materials are, stolen, damaged, rotting, corroding, and losing value in many other ways.
A key part of the lean approach is to minimize the amount of materials (both incoming and finished
goods) you have sitting around in your facility. Excess materials hide problems with purchasing, work
scheduling, scrap rates, and so on. Eliminating this excess materials provides an immediate financial
benefit to your company – if you eliminate correctly.
You don’t want to eliminate so thoroughly that you cause shortages. One method you can use
to fix the problem of excess materials without causing shortages is Kanban. Kanban is a materials
system controlled by the customer. When the customer buys an item, action cascades back up the
production line to make one more of that item.
Homework
Investigate and make a summary of the following topics:
 Total Quality Management (TQM)
 Six Sigma
 Toyota Production System (TPS)
Suggested videos
 http://www.youtube.com/watch?v=U7Z33tljMTQ
 http://www.youtube.com/watch?v=LdhC4ziAhgY

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Activities:
Write in each screw a different description about Quality Control:
Complete with the description of each lean technique:
Value stream Mapping
Rapid improvement events
Lean material and Kanban

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Complete the chart with the 5s technique:

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ALTERNATIVE ENERGY
Introduction
You need energy to start your day. Your breakfast is the fuel your body needs to work. What
would you do if you ran out of your favorite cereal? You could buy another box. But what if the store
was all out, too? What if it wasn’t getting any more deliveries? What would you do then? The answer
seems simple; you’d have to find another food for breakfast. The world faces a similar problem; our
fuel resources are running low and could run out in your lifetime.
Most everything in the world needs energy to work. Think about the energy you use each day:
the lights you turn on, the bus or car you take to school, the computer you use for homework, the
television you watch before bed. Even while you sleep, energy runs your furnace heating your house
and the refrigerator keeping food from spoiling. It even runs the alarm clock that wakes you up in the
morning. Now think about how many people live on the Earth. With a population of more than 6
billion, the world uses a lot of energy.
Today’s energy sources = fossil fuels
1. Coal
People mine for coal, a hard, black, rock,
throughout the world. Power plants use coal to generate
electricity by grinding it into a powder that is burned. The
burned powder heats water to create steam. The power of
the steam turns turbines. The spinning motion of the
turbines generates electricity. A network of wires called power grid, bring this electricity to houses
and other buildings.
2. Oil
Companies drill for oil on land or in the ocean and store it
in large barrels or underground tanks. People turn oil into
many products, including plastics. Your ballpoint pen, your

33
nylon backpack, and even your fleece jacket are all made from oil. Some homes burn oil for heat and
some power plants burn oil too. In many countries, however, oil’s main use is for transportation. Oil is
made into gasoline for cars, diesel fuel for trucks, and jet fuel for airplanes.
3. Natural gas
Companies drill for natural gas the same way they do for oil. Natural gas is highly flammable.
Gas stoves cook food with a lower flame. In the United States, and probably other countries, the
house’s heating system and water heater may use natural gas. Natural gas is also used in power
plants to create electricity.
The problems of the use of the fossil fuels
Fossil fuels have been a useful source of energy, but we need to rethink how much we depend
on them. We need to consider three main facts. First, fossil fuel supplies are low. We use so much
energy that someday we’ll use up all of Earth’s fossil fuels. At the rate we use now fossil fuels,
scientists’ estimate that the world’s reserve will last 40 to 70 more years. What will happen after all of
the oil, coal, and natural gas have run out? How will
we travel from place to place? How will we light our
homes? How will we communicate with each other?
The second fact is that the fossil fuels cost a
lot of money. Countries buy fossil fuels from each
other. Because the supply is low, they can raise their
prices. If countries go to war or have a disagreement,
they may not want to buy fuel from each other. No
one will get what they need.
Finally, burning fossil fuels harms Earth. Coal, oil, and natural gas create a lot of air pollution.
The burning of fossil fuels releases harmful emissions that cause asthma and other health problems.
This pollution also leads to acid rain and snow. Many scientist and citizens are concerned about the
carbon dioxide released by burning fossil fuels. Carbon dioxide belongs to a group of gases known as
greenhouse gases. As these gases collect in the atmosphere, they act like the glass walls of a
greenhouse, trapping warm air close to Earth’s surface. This warming is natural, and long ago it made
the planet’s environment mild enough to support life. However, when human activities pump larger-
than-normal amounts of carbon dioxide into the atmosphere, more heat is trapped, and

34
temperatures can grow unnaturally high. As a result, there can be major effects on weather that may
be devastating to the environment and all the people on Earth.
The solutions
What can we do about our energy problems? Instead of relying on fossil fuels, we need to
examine our “green” alternatives. Green energy is renewable – it is constantly being replaced and
won’t run out. Natural forces, such as wind, water, and sunlight are green energy sources. It’s not
easy to switch to green energy; however, we rely on fossil fuels every day. People would need to
spend huge amounts of money to change from one kind of fuel to another. We need to take action,
but first, we need to understand our energy alternatives, then we can make the best energy choices
to preserve our planet.
Solar energy
Put on sunglasses, rub in sunscreen, and hit the beach. It’s
time to soak up some rays! The sun can give you a great tan or make
you sweat playing Frisbee. The sun’s light and heat can also help us
solve our energy problems. You have probably noticed wires
running from your home to poles on the street. These wires connect
you to the power grid of your community. Home’s that use solar
power, don’t need as much energy from the grid. There are two
types of solar power: solar cell energy and solar thermal energy.
Solar Energy, the energy generated by the sun. This energy is in the form of electromagnetic
radiation and travels to the earth in waves of various lengths. Some of the radiation becomes evident
as heat, some as visible light. All life on earth depends ultimately on the sun's radiation. It warms the
earth and provides the energy that green plants use to make their food. (Without plants, there would
be no animals, since all animals must feed on plants or on plant-eating organisms.)
Since ancient times attempts have been made—with varying success—to put the energy from
the sun to practical use. In the third century B.C., the Greek mathematician and physicist Archimedes
is said to have used the sun's rays reflected from mirrors to set fire to an invading Roman fleet. In the
19th century, John Ericsson, designer of the ironclad warship Monitor, built an engine that was
powered by the sun's energy.

35
Solar Heat
Solar heat supplies energy for a variety of uses. The preservation of fruits, vegetables, meat,
and fish by sun drying has been practiced for centuries. Some industrial products are also dried by the
heat of the sun. In some warm, arid regions, the heat of the sun is used to evaporate seawater or
brines to recover salt and other minerals.
Water for domestic use can be heated by solar energy by the use of roof-mounted devices
consisting of heat collectors through which water pipes pass. As the water is heated it flows into
storage tanks. Heat collectors can also be used to heat homes and other buildings. The sun's heat is
transferred to a fluid—usually water or air—which then heats the interior of the building. For heating
at night and on cloudy days, some form of heat storage is necessary. A common storage system
consists of an insulated tank to hold solar-heated water. In many regions, additional heat from a
conventional heating system is required for extended cloudy or cold periods.
Industrial installations that use large arrays of mirrors to produce intense solar heating have
been developed in a number of countries. A large solar furnace at Odeillo, in the French Pyrenees,
uses an array of thousands of movable mirrors to direct sunlight on a parabolic mirror. This mirror
focuses the sunlight on an oven, yielding temperatures of more than 6,000° F. (3,300° C.). The furnace
is used to study the effects of high temperatures on certain substances and for various industrial
processes.
In the southwestern United States, a few experimental installations have been built that use a
large array of computer-controlled mirrors to concentrate sunlight onto a boiler atop a high tower.
Steam produced in the boiler powers a turbine that generates electricity.
Photovoltaic, or Solar, Cells
Photovoltaic cells convert sunlight directly into electricity. The cells are made of a
semiconductor material, usually silicon. A solar battery consists of an array of solar cells connected
together to generate electric power.
Solar batteries are the source of power on most artificial satellites. Solar batteries are used in
remote locations as a source of power for navigational buoys, irrigation pumps, and other equipment.
Small solar batteries are used in some calculators and wrist watches.

36
To a very limited extent solar batteries have been used to supply electric power to businesses
and residences. However, photovoltaic cells are relatively costly to manufacture and are thus not
practical for generating large amounts of electricity commercially. Research in the use of photovoltaic
cells for solar energy is directed toward finding ways of increasing the efficiency of the cells and of
reducing their cost.
How solar cell energy works
The solar cells that you see on calculators and satellites are also called photovoltaic (PV) cells,
which as the name implies (photo meaning "light" and voltaic meaning "electricity"), convert sunlight
directly into electricity. A module is a group of cells connected electrically and packaged into a frame
(more commonly known as a solar panel), which can then be grouped into larger solar arrays, like the
one operating at Nellis Air Force Base in Nevada.
Photovoltaic cells are made of special materials called
semiconductors such as silicon, which is currently used most
commonly. Basically, when light strikes the cell, a certain portion of it
is absorbed within the semiconductor material. This means that the
energy of the absorbed light is transferred to the semiconductor. The
energy knocks electrons loose, allowing them to flow freely.
PV cells also all have one or more electric field that acts to force electrons freed by light
absorption to flow in a certain direction. This flow of electrons is a current, and by placing metal
contacts on the top and bottom of the PV cell, we can draw that current off for external use, say, to
power a calculator. This current, together with the cell's voltage (which is a result of its built-in
electric field or fields), defines the power (or wattage) that the solar cell can produce.
That's the basic process, but there's really much more to it. On the next page, let's take a
deeper look into one example of a PV cell: the single-crystal silicon cell.
Silicon has some special chemical properties, especially in its crystalline form. An atom of sili-
con has 14 electrons, arranged in three different shells. The first two shells -- which hold two and
eight electrons respectively -- are completely full. The outer shell, however, is only half full with just
four electrons. A silicon atom will always look for ways to fill up its last shell, and to do this, it will
share electrons with four nearby atoms. It's like each atom holds hands with its neighbors, except that

37
in this case, each atom has four hands joined to four neighbors. That's what forms the crystalline
structure, and that structure turns out to be important to this type of PV cell.
The only problem is that pure crystalline silicon is a poor conductor of electricity because none
of its electrons are free to move about, unlike the electrons in more optimum conductors like copper.
To address this issue, the silicon in a solar cell has impurities -- other atoms purposefully mixed in with
the silicon atoms -- which changes the way things work a bit. We usually think of impurities as
something undesirable, but in this case, our cell wouldn't work without them. Consider silicon with an
atom of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has
five electrons in its outer shell, not four. It still bonds with its silicon neighbor atoms, but in a sense,
the phosphorous has one electron that doesn't have anyone to hold hands with. It doesn't form part
of a bond, but there is a positive proton in the phosphorous nucleus holding it in place.
When energy is added to pure silicon, in the form of heat for example, it can cause a few
electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These
electrons, called free carriers, then wander randomly around the crystalline lattice looking for another
hole to fall into and carrying an electrical current. However, there are so few of them in pure silicon,
that they aren't very useful.
But our impure silicon with phosphorous atoms mixed in is a different story. It takes a lot less
energy to knock loose one of our "extra" phosphorous electrons because they aren't tied up in a bond
with any neighboring atoms. As a result, most of these electrons do break free, and we have a lot
more free carriers than we would have in pure silicon. The process of adding impurities on purpose is
called doping, and when doped with phosphorous, the resulting silicon is called N-type ("n" for
negative) because of the prevalence of free electrons. N-type doped silicon is a much better
conductor than pure silicon.
The other part of a typical solar cell is doped with the element boron, which has only three
electrons in its outer shell instead of four, to become P-type silicon. Instead of having free
electrons, P-type ("p" for positive) has free openings and carries the opposite (positive) charge.
Before now, our two separate pieces of silicon were electrically neutral; the interesting part
begins when you put them together. That's because without an electric field, the cell wouldn't work;
the field forms when the N-type and P-type silicon come into contact. Suddenly, the free electrons on
the N side see all the openings on the P side, and there's a mad rush to fill them. Do all the free
electrons fill all the free holes? No. If they did, then the whole arrangement wouldn't be very useful.
However, right at the junction, they do mix and form something of a barrier, making it harder and

38
harder for electrons on the N side to cross over to the P side. Eventually, equilibrium is reached, and
we have an electric field separating the two sides.
This electric field acts as a diode, allowing (and even pushing) electrons to flow from the P side
to the N side, but not the other way around. It's like a hill -- electrons can easily go down the hill (to
the N side), but can't climb it (to the P side).
When light, in the form of photons, hits our solar cell, its energy breaks apart electron-hole
pairs. Each photon with enough energy will normally free exactly one electron, resulting in a free hole
as well. If this happens close enough to the electric field, or if free electron and free hole happen to
wander into its range of influence, the field will send the electron to the N side and the hole to the P
side. This causes further disruption of electrical neutrality, and if we provide an external current path,
electrons will flow through the path to the P side to unite with holes that the electric field sent there,
doing work for us along the way. The electron flow provides the current, and the cell's electric field
causes a voltage. With both current and voltage, we have power, which is the product of the two.
There are a few more components left before we can really use our cell. Silicon happens to be
a very shiny material, which can send photons bouncing away before they've done their job, so
an antireflective coating is applied to reduce those losses. The final step is to install something that
will protect the cell from the elements -- often a glass cover plate. PV modules are generally made by
connecting several individual cells together to achieve useful levels of voltage and current, and
putting them in a sturdy frame complete with positive and negative terminals.
How much sunlight energy does our PV cell absorb? Unfortunately, probably not an awful lot.
In 2006, for example, most solar panels only reached efficiency levels of about 12 to 18 percent. The
most cutting-edge solar panel system that year finally muscled its way over the industry's long-

39
standing 40 percent barrier in solar efficiency -- achieving 40.7 percent [source: U.S. Department of
Energy]. So why is it such a challenge to make the most of a sunny day?
The sun radiates approximately 1000W per square meter, so a 10 x 10 cm solar cell is exposed
to nearly 10 watts of radiated power. Depending on the quality of the cell, it can produce an electrical
output of 1 - 1.5 watts. To increase the output, several cells are combined and connected to a PV
module. The connection of several PV modules is also referred to as a PV array.
How solar thermal energy works
Solar thermal energy uses heat instead of light. People can
place thermal panels on their roofs to absorb the sun’s heat. Tubing
filled with water runs under the panels. The sun warms the water.
This water can then be used to make a cup of cocoa, fill a swimming
pool, or run through a home’s heating system.
Thermal energy can also create electricity. In a solar power plant, the sun heats a liquid until it
boils. Then the steam created from this boiling liquid runs a turbine to generate electricity. In order
for the liquids to boil, these power plants use mirror to focus the sun’s heat and increase its strength.
Some mirrors are curved and shaped like a saucer. Others are shaped like a trough or placed in a line.
Some new solar energy plants have a power tower. Thousands of mirrors surround the tower and
focus the sun’s heat to the top.

40
The solar collectors absorb the sun’s rays, convert them to heat and transfer the heat to a
heat-transfer fluid. (The heat-transfer fluid is typically a glycol and water mixture in regions where
seasonal freezing in a concern.) The heat-transfer fluid is then pumped into a heat exchanger located
inside the water storage tank where it heats the water.
After releasing its heat via the heat exchanger, the heat-transfer fluid flows back to the
collectors to be reheated. The controller keeps the heat-transfer fluid circulating whenever there is
heat available in the solar collectors. In the winter, a boiler serves as an alternate heat source. Solar
thermal systems can be integrated into existing hot water systems with relative ease.
A solar thermal system consists primarily of the following components:
 The collector, which is normally installed on the rooftop, represents the key component of a solar
thermal system. It consists of specially coated tubing that is used to absorb the solar radiation and to
convert it into heat. To minimize thermal losses, this tubing is embedded in a heat-insulated container
equipped with a transparent cover. A heat-transfer fluid (usually a mixture of water and ecologically-
safe anti-freeze) flows inside the tubing and circulates between the collector and hot water tank.
 The Solar Controller. Solar thermal systems are operated by a solar controller. Once the temperature
at the collector rises several degrees above the temperature in the storage tank, the solar controller
switches on the circulation pump and the heat-transfer fluid transports the heat accumulated in the
collector to the hot water tank.
 The Hot Water Tank. There are two basic kinds of tanks. Drinking water storage tanks are used for
heating drinking water and consist of steel tanks that are filled with drinking water and equipped with
two heat exchangers.
 Combination storage tanks are used for both drinking water and supplying heating systems. They have
two internal tanks to keep the water separated. The solar thermal circuit is connected to the lower
heat exchanger. The boiler connects to the upper heat exchanger.
In most cases, solar thermal energy systems are designed to meet 100% of a household’s
energy demands for water heating during the summer months from May to September. During the
winter months, the boiler will likely be used for space heating and can also heat water during that
time. In this way, solar energy accounts for approximately 60% of the energy used to heat water
throughout the year.

41
Generally speaking, the size of your solar thermal system will vary depending on the climate and
overall water usage. The following guidelines can be used to estimate your system requirements:
Collector surface area
 m
2
flat-plate collector surface per person
 1 m
2
evacuated tube collector surface per person
As you can see, evacuated tube type collectors are more efficient given the same area. This
may be something to consider if your rooftop is not very large.
Storage tank volumes
 20-30 gallons per person
Since household hot water requirements remain relatively consistent throughout the year, the
use of solar energy for hot water generation can be extremely cost-effective. The solar thermal
system can easily be designed to meet a specific household’s energy demands for hot water usage.
With a properly sized system, 50% to 65% of the annual hot water requirements would be provided
by solar energy – and during the summer, 100% could be achieved, allowing the conventional heating
system to be completely off during that time.
Wind Energy
Wind is moving air. The motion is caused by changes in air temperature. Warm air is light, and
cold air is heavy. When the land beats up during the day, it warms the air above it. This warm air rises
higher in the sky; while cold air moves down to fill the space left by the warm air. This movement of
air creates wind.
Wind can be powerful, as with a destructive hurricane, but its
power can also be used for good. Sailors use the wind to keep their
sailboats moving. Throughout history people have used windmills to
harness the wind’s energy for grinding grain or pumping well water. Today
people use wind turbines to generate electricity.

42
How wind power works
A wind turbine has what looks like an airplane
propeller mounted very high in a tower. The blades of the
turbine catch the wind and spin. The blades spin a shaft
that is connected to an electrical generator. Wires connect
the generator to the power grid to bring electricity to
buildings in the area.
To increase the amount of power, turbines are
often grouped in wind farms. Most wind farms aren’t
owned by electric power companies. They are owned by
“wind
farmers”
who sell the
electricity to
power companies. Wind turbines work best where wind
blows strongest. Wind is usually stronger the higher you
go. That’s why turbines are often mounted on tall
towers or placed on the top of hills. Some towers stand
between 100 and 250 feet (30 and 76 meters) high.
Shorelines and wide-open prairies are also good places
for towers. Turbines don’t work well in location of too
many mountains, forests, or buildings, which block the
wind’s flow. Some people place small turbines on their roofs and position them in a way to catch the
most wind.
The process of converting the wind into mechanical energy starts with the wind turbine blades. There
are two different types of blade designs, lift type and drag type:
 Lift Type: This is a common type of the modern horizontal axis wind turbine blade that you see at all
the big wind farms. This type of blade has a similar design of an airplane wing. As the air blows on both
side of the blade, it takes the air long to travel across the leading edge creating a lower air pressure and
higher air pressure on the tailing edge. This pressure difference ‘pulls’ and ‘pushes’ the blade around.
Lift type blades have much higher rotational speeds than drag type, which make them well suited for
generating electricity.
 Drag Type – The first type of wind turbines created used a drag design. This type of wind turbine uses
the force of the wind to push the blade. A savonius is a perfect example of this design type, the wind is
resisted by blade and the wind’s force on it pushes it around. This design normally creates a slower

43
rotational speed with a higher torque than a lift type design. This design has been used for centuries
for milling, sawing, pumping, but rarely used for energy generation on large scale.
The rotating blades are connected to a shaft which is connected to a generator. Some micro
wind turbines are designed to be direct drive, where the blades connect directly to a low RPM
generator, usually around 500+ RPM. The larger wind turbines make the use of gears to increase a
slow blade turn, sometimes as slow as 9 RPM, into 1800+ RPM that can be used to drive a generator.
These gears lose energy and cause additional cost, maintenance, and downtime. Many recent
advances and ingenuity has gone into improving the design.
How is the electricity created?
The generator uses the turning
motion to spin a magnetic rotor inside
the generator housing that is
surrounded by loops of copper wire
(often wrapped around iron cores). As
the rotor spins around the inside of the
core it excites "electromagnetic
induction" through the wire that
generates an electrical current.
Where does the wind come from?
The sun’s energy fuels our wind. As solar rays come
down hit Earth they heat it up. Wind is created by the Earth
unevenly heating. The irregularities of the Earth cause the
sun’s rays to heat differently from one area to the next. This
creates areas with different pressures; nature will balance
these differences by moving higher pressure air toward the
lower pressure air which is wind.
Types of Wind Turbines
Wind turbines can be separated into two basic types
determined by which way the turbine spins. Wind turbines
that rotate around a horizontal axis are more common (like a
wind mill), while vertical axis wind turbines are less frequently
used (Savonius and Darrieus are the most common in the group).

44
Horizontal Axis Wind Turbines (HAWT)
Horizontal axis wind turbines, also shortened to HAWT,
are the common style that most of us think of when we think of
a wind turbine. A HAWT has a similar design to a windmill, it has
blades that look like a propeller that spin on the horizontal axis.
Horizontal axis wind turbines have the main rotor shaft
and electrical generator at the top of a tower, and they must be
pointed into the wind. Small turbines are pointed by a simple
wind vane placed square with the rotor (blades), while large
turbines generally use a wind sensor coupled with a servo motor
to turn the turbine into the wind. Most large wind turbines have
a gearbox, which turns the slow rotation of the rotor into a faster
rotation that is more suitable to drive an electrical generator.
Since a tower produces turbulence behind it, the turbine
is usually pointed upwind of the tower. Wind turbine blades are
made stiff to prevent the blades from being pushed into the
tower by high winds. Additionally, the blades are placed a
considerable distance in front of the tower and are sometimes
tilted up a small amount.
Downwind machines have been built, despite the problem of turbulence, because they don't
need an additional mechanism for keeping them in line with the wind. Additionally, in high winds the
blades can be allowed to bend which reduces their swept area and thus their wind resistance. Since
turbulence leads to fatigue failures, and reliability is so important, most HAWTs are upwind machines.
HAWT advantages
 The tall tower base allows access to stronger wind in sites with wind shear. In some wind shear sites,
every ten meters up the wind speed can increase by 20% and the power output by 34%.
 High efficiency, since the blades always move perpendicularly to the wind, receiving power through the
whole rotation. In contrast, all vertical axis wind turbines, and most proposed airborne wind turbine
designs, involve various types of reciprocating actions, requiring airfoil surfaces to backtrack against
the wind for part of the cycle. Backtracking against the wind leads to inherently lower efficiency.

45
HAWT disadvantages
 Massive tower construction is required to support the heavy blades, gearbox, and generator.
 Components of a horizontal axis wind turbine (gearbox, rotor shaft and brake assembly) being lifted
into position.
 Their height makes them obtrusively visible across large areas, disrupting the appearance of the
landscape and sometimes creating local opposition.
 Downwind variants suffer from fatigue and structural failure caused by turbulence when a blade passes
through the tower's wind shadow (for this reason, the majority of HAWTs use an upwind design, with
the rotor facing the wind in front of the tower).

HAWTs require an additional yaw control mechanism to turn the blades toward the wind.
 HAWTs generally require a braking or yawing device in high winds to stop the turbine from spinning
and destroying or damaging itself.
Cyclic stresses and vibration
When the turbine turns to face the wind, the rotating blades act like a gyroscope. As it pivots,
gyroscopic precession tries to twist the turbine into a forward or backward somersault. For each blade
on a wind generator's turbine, force is at a minimum when the blade is horizontal and at a maximum
when the blade is vertical. This cyclic twisting can quickly fatigue
and crack the blade roots, hub and axle of the turbines.
Vertical axis
Vertical axis wind turbines, as shortened to VAWTs, have
the main rotor shaft arranged vertically. The main advantage of
this arrangement is that the wind turbine does not need to be
pointed into the wind. This is an advantage on sites where the
wind direction is highly variable or has turbulent winds.
With a vertical axis, the generator and other primary
components can be placed near the ground, so the tower does not
need to support it, also makes maintenance easier. The main
drawback of a VAWT generally create drag when rotating into the
wind.
It is difficult to mount vertical-axis turbines on towers, meaning they are often installed nearer
to the base on which they rest, such as the ground or a building rooftop. The wind speed is slower at a
lower altitude, so less wind energy is available for a given size turbine. Air flow near the ground and

46
other objects can create turbulent flow, which can introduce issues of vibration, including noise and
bearing wear which may increase the maintenance or shorten its service life. However, when a
turbine is mounted on a rooftop, the building generally redirects wind over the roof and this can
double the wind speed at the turbine. If the height of the rooftop mounted turbine tower is
approximately 50% of the building height, this is near the optimum for maximum wind energy and
minimum wind turbulence.
VAWT subtypes
Darrieus wind turbine
Darrieus wind turbines are commonly called "Eggbeater" turbines, because they look like a
giant eggbeater. They have good efficiency, but produce large torque ripple and cyclic stress on the
tower, which contributes to poor reliability. Also, they generally require some external power source,
or an additional Savonius rotor, to start turning, because the starting torque is very low. The torque
ripple is reduced by using three or more blades which results in a higher solidity for the rotor. Solidity
is measured by blade area over the rotor area. Newer Darrieus type turbines are not held up by guy-
wires but have an external superstructure connected to the top bearing.
Savonius wind turbine
A Savonius is a drag type turbine, they are commonly used in cases of high reliability in many
things such as ventilation and anemometers. Because they are a drag type turbine they are less
efficient than the common HAWT. Savonius are excellent in areas of turbulent wind and self starting.
VAWT advantages
 No yaw mechanisms is needed.
 A VAWT can be located nearer the ground, making it easier to maintain the moving parts.
 VAWTs have lower wind startup speeds than the typical the HAWTs.
 VAWTs may be built at locations where taller structures are prohibited.
 VAWTs situated close to the ground can take advantage of locations where rooftops, mesas,
hilltops, ridgelines, and passes funnel the wind and increase wind velocity.
VAWT disadvantages

Most VAWTs have a average decreased efficiency from a common HAWT, mainly because of the
additional drag that they have as their blades rotate into the wind. Versions that reduce drag produce
more energy, especially those that funnel wind into the collector area.

47
 Having rotors located close to the ground where wind speeds are lower and do not take advantage of
higher wind speeds above.
 Because VAWTs are not commonly deployed due mainly to the serious disadvantages mentioned
above, they appear novel to those not familiar with the wind industry. This has often made them the
subject of wild claims and investment scams over the last 50 years.
Geothermal energy
Old faithful, Yellowstone National Park’s most
famous geyser, erupts with thousands of gallons of water
and steam every hour to hour and a half. This popular
Wyoming tourist spot is the home to more than 60
percent of the world’s geysers. In just one square mile
(2.6 square kilometers), you can see more than a 150 of
them.
Some people think of Earth as a solid ball of rock,
but it has many layers. At the center, Earth has a solid
core. Around this core is an area
of hot, liquid rock called magma.
Above the magma is a layer of
solid rock and magma called the
mantle. The temperature of the
mantle can be very high – from
2,520 to 5,400 degrees
Fahrenheit (1,382 to 2,982
degrees Celsius) depending on
how deep you go. The surface of
Earth, the crust, sits on the
mantle.
Water sometimes collects
in the rocks underground and
heats up. If there is a vent leading from this deep rock to the surface, superheated water shoots
upward. Earth’s crust is thicker in some areas than others.

48
Homework
 Investigate at least 15 technical words from this chapter that you previously did not know and
write the translation and definition of each
 Investigate about the following topics: magma, and mantle
 Watch the suggested videos. Then, answer this question: What could you do help to introduce people
to living a "green" life? What are some ways to change their way of thinking and living?
Suggested videos:
 http://www.youtube.com/watch?v=oIU5fFmDeSc
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Activities
Write in each square and explain some energy sources:

49
Bioethanol production
In recent years, largely in response to uncertain fuel supply and efforts to reduce carbon
dioxide emissions, bioethanol (along with biodiesel) has become one of the most promising biofuels
today and is considered as the only feasible short to medium alternative to fossil transport
fuels in Europe and in the wider world.
Bioethanol is seen as a good fuel alternative because the source crops can be grown
renewably and in most climates around the world. In addition the use of bioethanol is generally
CO2 neutral. This is achieved because in the growing phase of the source crop, CO2 is absorbed
by the plant and oxygen is released in the same volume that CO2 is produced in the combustion of
the fuel. This creates an obvious advantage over fossil fuels which only emit CO2 as well as other
poisonous emissions. In the 1970s, Brazil and the USA started mass production of bioethanol -grown
from sugarcane and corn respectively. Smaller scale production started more recently in Spain,
France and Sweden mostly from wheat and sugar beet.
In recent years the concept of the bio-refinery has emerged, whereby one integrates
biomass conversion processes and technology to produce a variety of products including fuels,
power, chemicals and feed for cattle. In this manner one can take advantage of the natural
differences in the chemical and structural composition of the biomass feed stocks.
The production of bioethanol from traditional means, or 1
st
Generation Biofuels is based
upon starch crops like corn and wheat and from sugar crops like sugar cane and sugar beet.
However, the cultivation of alternative sugar crops like sweet sorghum opens up new
possibilities in Europe, especially in hotter and drier regions, such as Southern and Eastern
Europe. Sweet sorghumrequires less water or nutrients and has a higher fermentable sugar
content than sugar cane as well as a shorter growing period which means that in some regions
like in Africa you can get 2 harvests a year from the same crop. In addition to this, the
development of lingo-cellulosic technology has meant that not only high energy content starch
and sugar crops can be used but also woody biomass or waste residues from forestry. This
development is seen as the 2
nd
Generation of Biofuels.
Depending on the biomass source the steps generally include:
1. Storage
2. Cane crushing and juice extraction
3. Dilution
4. Hydrolysis for starch and woody biomass
5. Fermentation with yeast and enzymes

50
6. CO2 storage and ethanol recapture
7. Evaporation
8. Distillation
9. Waste water treatment
10. Fuel Storage
What is Bioethanol?
The principle fuel used as a petrol substitute for road transport vehicles is bioethanol.
Bioethanol fuel is mainly produced by the sugar fermentation process, although it can also be
manufactured by the chemical process of reacting ethylene with steam.
The main sources of sugar required to produce ethanol come from fuel or energy crops. These
crops are grown specifically for energy use and include corn, maize and wheat crops, waste straw,
willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke,
myscanthus and sorghum plants. There is also ongoing research and development into the use of
municipal solid wastes to produce ethanol fuel.
Ethanol or ethyl alcohol (C2H5OH) is a clear colourless liquid, it is biodegradable, low in toxicity
and causes little environmental pollution if spilt. Ethanol burns to produce carbon dioxide and water,
is a high octane fuel and has replaced lead as an octane enhancer in petrol. By blending ethanol with
gasoline we can also oxygenate the fuel mixture so it burns more completely and reduces polluting
emissions. Ethanol fuel blends are widely sold in the United States. The most common blend is 10%
ethanol and 90% petrol (E10). Vehicle engines require no modifications to run on E10 and vehicle
warranties are unaffected also. Only flexible fuel vehicles can run on up to 85% ethanol and 15%
petrol blends (E85).
Benefits
Bioethanol has a number of advantages over conventional fuels. It comes from a renewable
resource i.e. crops and not from a finite resource and the crops it derives from can grow well (like
cereals, sugar beet and maize). Another benefit over fossil fuels is the greenhouse gas emissions. The
road transport network accounts for 22% of all greenhouse gas emissions and through the use of
bioethanol, some of these emissions will be reduced as the fuel crops absorb the CO2 they emit
through growing. Also, blending bioethanol with petrol will help extend the life of the diminishing oil
supplies and ensure greater fuel security, avoiding heavy reliance on oil producing nations.

51
By encouraging bioethanol’s use, the rural economy would also receive a boost from growing
the necessary crops. Bioethanol is also biodegradable and far less toxic that fossil fuels. In addition, by
using bioethanol in older engines can help reduce the amount of carbon monoxide produced by the
vehicle thus improving air quality.
Another advantage of bioethanol is the ease with which it can be easily integrated into the
existing road transport fuel system. In quantities up to 5%, bioethanol can be blended with
conventional fuel without the need of engine modifications. Bioethanol is produced using familiar
methods, such as fermentation, and it can be distributed using the same petrol forecourts and
transportation systems as before.
Bioethanol Production
Ethanol can be produced from biomass by the hydrolysis and sugar fermentation processes.
Biomass wastes contain a complex mixture of carbohydrate polymers from the plant cell walls known
as cellulose, hemi cellulose and lignin. In order to produce sugars from the biomass, the biomass is
pre-treated with acids or enzymes in order to reduce the size of the feedstock and to open up the
plant structure. The cellulose and the hemi cellulose portions are broken down (hydrolysed) by

52
enzymes or dilute acids intosucrose sugar that is then fermented into ethanol. The lignin which is
also present in the biomass is normally used as a fuel for the ethanol production plants boilers. There
are three principle methods of
extracting sugars from
biomass. These are
concentrated acid hydrolysis,
dilute acid hydrolysis and
enzymatic hydrolysis.
Production Process:
1. Grinding Grain
First, starch should be exposed
from the peel of corn to contact
with water. Also, grinding makes
corn small pieces, which can
increase its surface area. Then,
the increase in its surface area
can enhance the contact between
starch and water. Two types of
mills, a roller mill and a hammer
mill, are usually employed. For an
industrial use, a hammer mill is
mostly used because of its
accuracy and its application for
large amount.
A roller mill has some roll pairs
consisting of two rollers. Corn is
pressed by two rollers and
crushed into small pieces. Around
the rolls there are some trenches
to improve the effectiveness of
the crush. Also, the rotating
speeds of two rollers are different
in order to generate more stress
on the corn. Finally, screening is
implemented at the bottom of
the mill. Then, the fine particles
can pass the screen, and the big
particles, which cannot match

53
the required size, become the subject of the grinding again.
2. Fermentation:
Yeast is a facultative anaerobe. In an aerobic environment, it converts sugars into carbon dioxide and
water. In an anaerobic environment, it converts sugars into carbon dioxide and ethanol. Thus, for an ethanol
industry, it is important to exclude significant oxygen from its system. This fermentation process is relatively
slow process, so it is important for an industrial use to make it faster. Usually, a propagation tank is employed.
In this tank, mash, water, enzymes, nutrients, and yeast are mixed to re-hydrate the yeast.
3. Distillation:
After fermentation, we have to make the
purity of ethanol higher. Distillation is one of the
steps of the purifications. Distillation is the
method to separate two liquid utilizing their
different boiling points.
However, to achieve high purification,
several distillations are required. This is because
all materials have intermolecular interactions
with each other, and two materials will co-distill
during distillation. This means that proportion
between two materials, in this case ethanol and
water, can be changed, still, there are two
materials in both layers, the liquid and the vapor
layers.
4. Dehydration
As stated above, after traditional
distillation, about 5% of water remains in
ethanol. Especially, this water is a big problem for
fuel ethanol because the presence of this amount
of water enhances the molecular polarity of
ethanol for example ethanol and gasoline are mixed, they separate into two phases, ethanol phase and
gasoline phase. It is easy to imagine that this inhomogeneous fuel is not acceptable. Thus, dehydration can be
another issue.
Bioethanol Usage
Chemicals
A number of chemicals are produced in the ethanol industry and potentially even more in the
2
nd
. generation bioethanol industry, serving a wide range of uses in the pharmaceuticals, cosmetics,
beverages and medical sectors as well as for industrial uses. The market potential for bioethanol is

54
therefore not just limited to transport fuel or energy production but has potential to supply the existing
chemicals industry.
Transport Fuel:
Bioethanol has mostly been used as a biofuel for transport, especially in Brazil. Indeed
it was in Brazil where the first bioethanol fuelled cars emerged on a large-scale. Although
generally unknown to the average consumer, a large volume of bioethanol is already used in
Europe as it is blended with petrol at 5%. It is used as a substitute for lead as an oxygenating additive
and has a high octane rating, which improves performance. Although the eventual target is the
private consumer, few are aware of bioethanol’s potenial to, at least, partly replace petrol as
a transport fuel in Europe.
Stakeholders in the Bioethanol Fuel Market:
 Bioethanol producers
 Fuel suppliers
 Car manufacturers
 The government
Fuel Cells:
Fuel cells are another
potential area for ethanol use to
produce heat and power. Fuel
cells function by combining the
fuel hydrogen with oxygen from
the air to produce electrical
energy, with water vapour
and heat as by-products. Fuel
Cells have a typical electrical
efficiency of between 30 and
60 % and an overall efficiency,
if using the heat by-product, of
70-90 %. The units run with
very low noise emissions and pollutant gas emissions are also reduced considerably. It’s
disadvantages are its relatively high cost and their short life span (regular replacement of

55
components). They are, however, regarded as very reliable for the duration of their lifespan and
are often used for emergency power.
Negative sides of Bioethanol
Bioethanol has some deficit. Next figure shows some environmental impacts of ethanol in
gasoline. Although, some of them may be exaggerated, but this approach is very important when we
are considering bioethanol from overall environmental aspects. Corn production causes more soil
erosion and uses more herbicides and insecticides. Also, wastewater from ethanol plant is also
another big problem.
In addition, an increase in the demand of bioethanol may burden on our money. This is because,
currently, ethanol production is supported by huge subsidies coming from our tax. Besides, an
increase in the ethanol production means an increase in the demand of corn . This may cause an
increase in the corn price. Today, corn is everywhere in our meal.
Therefore, there are still so many concerns to say bioethnaol is a real ideal energy source.

56
Activities
 Use the box below to describe the picture of the Bioethanol production where you can see the
different steps of the process:

57
 Write True or False according to the sentence:
Ethanol can be produced from biomass by the hydrolysis and sugar fermentation processes.
By encouraging bioethanol’s use, the rural economy would never receive a boost from growing the necessary
crops:
Fuel Cells have a typical electrical efficiency of between 30 and 60 %
An increase in the ethanol production means an inrease in the demand of corn. This may cause a decrease in
the corn price.
After fermentation comes Grinding in Bioethanol production:
The most common blend is 10% ethanol and 90% petrol (E10):
Write a comment about the importance of Bioethanol in the economy of a country:

58
3. With the next picture do a “Proccess diagram” to recognize the activity in each part of the Bioethanol
production writing each specification in the square below.
BIBLIOGRAPHY
Lean Manufacturing:
References

59
Gears
Gears are used in tons of mechanical devices. They do several
important jobs, but most important, they provide a gear reduction in
motorized equipment. This is key because, often, a small motor spinning
very fast can provide enough power for a device, but not enough torque.
For instance, an electric screwdriver has a very large gear reduction
because it needs lots of torque to turn screws, but the motor only produces a small amount of torque
at a high speed. With a gear reduction, the output speed can be reduced while the torque is
increased.
Another thing gears do is adjust the direction of rotation. For instance, in the differential
between the rear wheels of your car, the power is transmitted by a shaft that runs down the center of
the car, and the differential has to turn that power 90 degrees to apply it to the wheels.
There are a lot of intricacies in the different types of gears. In this article, we'll learn exactly how the
teeth on gears work, and we'll talk about the different types of gears you find in all sorts of
mechanical gadgets.
On any gear, the ratio is determined by the distances from the center of the gear to the point
of contact. For instance, in a device with two gears, if one gear is twice the diameter of the other, the
ratio would be 2:1.
One of the most primitive types of gears we could look at would be a wheel with wooden pegs
sticking out of it.
The problem with this type of gear is that the distance from the center of each gear to the
point of contact changes as the gears rotate. This means that the gear ratio changes as the gear turns,
meaning that the output speed also changes. If you used a gear like this in your car, it would be
impossible to maintain a constant speed -- you would be accelerating and decelerating constantly.
Many modern gears use a special tooth profile called an involute. This profile has the very important
property of maintaining a constant speed ratio between the two gears. Like the peg wheel above, the
contact point moves; but the shape of the involute gear tooth compensates for this movement.
Types of Gears

60
Spur gears are the most common type of gears. They have
straight teeth, and are mounted on parallel shafts. Sometimes,
many spur gears are used at once to create very large gear
reductions. Spur gears are used in many, like the electric
screwdriver, dancing monster, oscillating sprinkler, windup alarm
clock,washing machine andclothes dryer. But you won't find
many in your car. This is because the spur gear can be really loud. Each time a gear tooth engages a
tooth on the other gear, the teeth collide, and this impact makes a noise. It also increases the stress
on the gear teeth. To reduce the noise and stress in the gears, most of the gears in your car
are helical.
In the Helical Gears The teeth on helical gears are cut at
an angle to the face of the gear. When two teeth on a helical gear
system engage, the contact starts at one end of the tooth and
gradually spreads as the gears rotate, until the two teeth are in
full engagement. This gradual engagement makes helical gears
operate much more smoothly and quietly than spur gears. For
this reason, helical gears are used in almost all car transmissions.
Because of the angle of the teeth on helical gears, they create a thrust load on the gear when they
mesh. Devices that use helical gears have bearings that can support this thrust load. One interesting
thing about helical gears is that if the angles of the gear teeth are correct, they can be mounted on
perpendicular shafts, adjusting the rotation angle by 90 degrees.
Bevel gears are useful when the direction of a shaft's
rotation needs to be changed. They are usually mounted on
shafts that are 90 degrees apart, but can be designed to work
at other angles as well. The teeth on bevel gears can
be straight, spiral or hypoid. Straight bevel gear teeth actually
have the same problem as straight spur gear teeth -- as each
tooth engages, it impacts the corresponding tooth all at once.
Just like with spur gears, the solution to this problem is to
curve the gear teeth. These spiral teeth engage just like helical teeth: the contact starts at one end of
the gear and progressively spreads across the whole tooth.

61
On straight and spiral bevel gears, the shafts must be perpendicular to each other, but they must also
be in the same plane. If you were to extend the two shafts past the gears, they would intersect.
The hypoid gear, on the other hand, can engage with the axes in different planes.
Figure. Hypoid bevel gears in a car differential
This feature is used in many car differentials. The ring gear of the differential and the input pinion
gear are both hypoid. This allows the input pinion to be mounted lower than the axis of the ring
gear. Figure shows the input pinion engaging the ring gear of the differential. Since the driveshaft of
the car is connected to the input pinion, this also lowers the driveshaft. This means that the driveshaft
doesn't intrude into the passenger compartment of the car as much, making more room for people
and cargo.
Worm gears are used when large gear reductions are needed. It is
common for worm gears to have reductions of 20:1, and even up
to 300:1 or greater. Many worm gears have an interesting
property that no other gear set has: the worm can easily turn the
gear, but the gear cannot turn the worm. This is because the
angle on the worm is so shallow that when the gear tries to spin
it, the friction between the gear and the worm holds the worm in
place. This feature is useful for machines such as conveyor
systems, in which the locking feature can act as a brake for the
conveyor when the motor is not turning. One other very
interesting usage of worm gears is in theTorsen differential,
which is used on some high-performance cars and trucks.

62
Rack and pinion gears are used to convert rotation into linear
motion. A perfect example of this is the steering system on
many cars. The steering wheel rotates a gear which engages
the rack. As the gear turns, it slides the rack either to the right
or left, depending on which way you turn the wheel.
Rack and pinion gears are also used in some scales to turn the
dial that displays your weight.
Bearings
The concept behind a bearing is very simple: Things roll better than they slide. The wheels on
your car are like big bearings. If you had something like skis instead of wheels, your car would be a lot
more difficult to push down the road.
That is because when things slide, the friction between
them causes a force that tends to slow them down. But if the two
surfaces can roll over each other, the friction is greatly reduced.
A simple bearing, like the kind found in a skate wheel. Bearings
reduce friction by providing smooth metal balls or rollers, and a
smooth inner and outer metal surface for the balls to roll against.
These balls or rollers "bear" the load, allowing the device to spin
smoothly.
Bearings typically have to deal with two kinds of
loading, radial and thrust. Depending on where the bearing is being
used, it may see all radial loading, all thrust loading or a
combination of both. The bearings in theelectric motor and
the pulley pictured above face only a radial load. In this case, most
of the load comes from the tension in the belt connecting the two pulleys.
The bearing above is like the one in a barstool. It is loaded purely in thrust, and the entire load comes
from the weight of the person sitting on the stool.

63
The bearings in a car wheel are
subject to both thrust and radial
loads.
The bearing above is like the one in
the hub of your car wheel. This
bearing has to support both a radial
load and a thrust load. The radial load
comes from the weight of the car, the
thrust load comes from the cornering
forces when you go around a turn.
Types of Bearings
There are many types of bearings, each used for different
purposes. These include ball bearings, roller bearings, ball thrust
bearings, roller thrust bearings and tapered roller thrust bearings.
Ball bearings, are probably the most common type of bearing.
They are found in everything from inline skates to hard drives. These
bearings can handle both radial and thrust loads, and are usually found
in applications where the load is relatively small.
In a ball bearing, the load is transmitted from the outer race to the ball,
and from the ball to the inner race. Since the ball is a sphere, it only
contacts the inner and outer race at a very small point, which helps it
spin very smoothly. But it also means that there is not very much
contact area holding that load, so if the bearing is overloaded, the balls
can deform or squish, ruining the bearing.
Roller bearings like the one illustrated below are used in applications
like conveyer belt rollers, where they must hold heavy radial loads. In these
bearings, the roller is a cylinder, so the contact between the inner and outer
race is not a point but a line. This spreads the load out over a larger area,
allowing the bearing to handle much greater loads than a ball bearing.
However, this type of bearing is not designed to handle much thrust loading. A
variation of this type of bearing, called a needle bearing, uses cylinders with a
very small diameter. This allows the bearing to fit into tight places.

64
Ball thrust bearings like the one shown below are mostly used for low-speed applications and cannot
handle much radial load. Barstools and Lazy Susan turntables use this type of bearing.
Roller thrust bearingslike the one
illustrated below can support large thrust
loads. They are often found in gearsets
like car transmissions between gears, and
between the housing and the rotating
shafts. Thehelical gears used in most transmissions have angled teeth -- this causes a thrust load that
must be supported by a bearing.
Tapered roller bearings can support large radial and large
thrust loads. Tapered roller bearings are used in car hubs,
where they are usually mounted in pairs facing opposite
directions so that they can handle thrust in both directions.
Some Interesting Uses
There are several types of bearings, and each has its own interesting uses, including magnetic
bearings and giant roller bearings.
 Magnetic Bearings. Some very high-speed devices, like advanced flywheel energy storage
systems, use magnet bearings. These bearings allow the flywheel to float on a magnetic field
created by the bearing. Some of the flywheels run at speeds in excess of 50,000 revolutions
per minute (rpm). Normal bearings with rollers or balls would melt down or explode at these
speeds. The magnetic bearing has no moving parts, so it can handle these incredible speeds.
 Giant Roller Bearings. Probably the first use of a bearing was back when the Egyptians were
building the pyramids. They put round logs under the heavy stones so that they could roll
them to the building site. This method is still used today when large, very heavy objects like
the Cape Hatteras lighthouseneed to be moved.
 Earthquake-Proof Buildings. The new San Francisco International Airport uses many advanced
building technologies to help it withstandearthquakes. One of these technologies involves
giant ball bearings.

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