The document discusses proper ledge profiles in aluminum reduction cells. An ideal ledge would have a sloped saddle dropping off steeply below, not extending far under the anode shadow. Extended or large ledges reduce surface area and disrupt heat flow, potentially causing spikes or shatter. Measuring ledge extension is important, as excessive extension lowers efficiency and increases voltage. Maintaining a stable ratio and avoiding ledge growth is key to optimizing cell performance.
Aluminium World Journal 2014 Edition;
contains editorials, advertisements, case studies, and company profiles from, for and about the global aluminium industry. This edition contains a special feature from TMEIC.
Articles presented include Rio Tinto Alcan on the start-up of the AP60 Technological Centre, a 2014 Review on Reduction Cell Technology Providers, Hydro Aluminium’s historical evolution of closed type anode baking furnace technology. Sections include:
Primary Smelting and Processes
Anode Plant Technology
Materials Handling And Transportation
Companies participating include:
ABB AB Force Measurement www.abb.com/measurement
ABB Switzerland Ltd. www.abb.com/aluminium
Alcoa Inc. www.alcoa.com
Cargotec/Siwertell www.siwertell.com
ECL www.ecl.fr
Fives www.fivesgroup.com
FLSmidth www.flsmidth.com
Hycast A/S www.hycast.no
Hydro www.hydro.com
Innovatherm www.innovatherm.de
Power Jacks www.powerjacks.com
Rio Tinto Alcan www.riotintoalcan.com
RTA AP-Technology www.ap-technology.com
RTA Alesa Ltd. www.rta-alesa.com
Sensotech www.sensotech.com
TMEIC www.tmeic.com
UC Rusal www.rusal.ru/en/
Vigan
Published by; Global Media Communication Ltd.
Online @; www.globalmediacommunication.com
This document provides information about troubleshooting catalytic reactors. It begins with definitions of key terms like catalyst, activity, selectivity, and sintering. It then discusses common symptoms of issues like higher than expected pressure drop, rapid decline in conversion, and temperature runaways. For each symptom, it lists possible causes such as catalyst degradation, poisoning, maldistribution of gas flow, and inadequate heat transfer. It also covers mechanisms of catalyst deactivation like thermal sintering, chemical poisoning, and mechanical fouling. Overall, the document concisely outlines how to diagnose problems in catalytic reactors based on observable symptoms and their potential root causes.
Die materials and technique of fabricationAsa Yomi
This document discusses various materials and techniques used for fabricating dental dies. It describes common die materials like gypsum products, electroplated dies, epoxy resins, and ceramic materials. It outlines the basic requirements for die materials including the ability to reproduce fine detail, dimensional accuracy and stability, mechanical properties, and compatibility with impression materials. The document provides details on the manufacture and setting of gypsum products, the electroplating process for copper and silver dies, and the use of amalgam for die fabrication.
Molten salts corrode heat resistant alloys by dissolving the protective chromium oxide scale. Good performance of salt pots depends more on maintenance than alloy selection. Higher nickel alloys like 600 generally perform better than 309 or 330 in molten salt, but alloy choice is less important than proper maintenance to prevent salt contamination, oxygen buildup, and sludge accumulation.
1. The document discusses the scabbing defect that occurs in metal casting due to high temperatures in the mold material. At the entrance to the ingate, temperatures reach 1440°C, inducing compressive stresses on the mold surface that cause scabbing.
2. The study investigated modifying the ingate design to reduce turbulence in the molten metal flow and decrease heat transfer to the mold, which can relieve compressive stresses. The rectangular ingate profile was replaced with a gradually widening 60° profile to reduce sudden changes in cross-section.
3. Experimental results found that the modified ingate design decreased turbulence in the molten metal flow, transforming it from turbulent to more laminar. This reduced loosening of
This document provides information on constructing electrolyzers, which produce a mixture of hydrogen and oxygen gases ("hydroxy gas") through electrolysis of water. It describes three main types of electrolyzers: single cell units running off 12 volts, series connections of multiple 12 volt cells, and high-voltage series cells. Safety is the top priority, as hydroxy gas is highly explosive. Features like relays, circuit breakers, pressure release valves, and bubblers are recommended to minimize risks.
The document discusses various welding defects including lamellar tearing, porosity, underfill, insufficient
penetration, wagon tracks, arc strikes, and incomplete fusion. Lamellar tearing occurs beneath welds in rolled steel
plate and is caused by transverse strain from welding, a weld orientation parallel to inclusions, and poor material
ductility. Porosity is caused by absorbed gases like nitrogen, oxygen, and hydrogen which become trapped during
solidification. Prevention methods for defects include using proper joint design, welding techniques, materials, and
preheating when necessary. Defects require removal and rewelding to repair.
This document discusses the causes of rust bleeding in galvanized parts. Rust bleeding occurs when moisture and cleaning chemicals get trapped behind welds or in sealed areas during the galvanizing process. This can happen due to issues with venting trapped air out of enclosed welding areas, using stitch welds that leave gaps, or having pinholes in seal welds. While rust bleeding may appear to be the galvanizer's fault, the document explains that the root causes are usually design and fabrication choices rather than issues with the galvanizing process itself. The best solutions involve allowing gaps for zinc to fill during galvanizing or plugging rust bleeds after the fact.
Aluminium World Journal 2014 Edition;
contains editorials, advertisements, case studies, and company profiles from, for and about the global aluminium industry. This edition contains a special feature from TMEIC.
Articles presented include Rio Tinto Alcan on the start-up of the AP60 Technological Centre, a 2014 Review on Reduction Cell Technology Providers, Hydro Aluminium’s historical evolution of closed type anode baking furnace technology. Sections include:
Primary Smelting and Processes
Anode Plant Technology
Materials Handling And Transportation
Companies participating include:
ABB AB Force Measurement www.abb.com/measurement
ABB Switzerland Ltd. www.abb.com/aluminium
Alcoa Inc. www.alcoa.com
Cargotec/Siwertell www.siwertell.com
ECL www.ecl.fr
Fives www.fivesgroup.com
FLSmidth www.flsmidth.com
Hycast A/S www.hycast.no
Hydro www.hydro.com
Innovatherm www.innovatherm.de
Power Jacks www.powerjacks.com
Rio Tinto Alcan www.riotintoalcan.com
RTA AP-Technology www.ap-technology.com
RTA Alesa Ltd. www.rta-alesa.com
Sensotech www.sensotech.com
TMEIC www.tmeic.com
UC Rusal www.rusal.ru/en/
Vigan
Published by; Global Media Communication Ltd.
Online @; www.globalmediacommunication.com
This document provides information about troubleshooting catalytic reactors. It begins with definitions of key terms like catalyst, activity, selectivity, and sintering. It then discusses common symptoms of issues like higher than expected pressure drop, rapid decline in conversion, and temperature runaways. For each symptom, it lists possible causes such as catalyst degradation, poisoning, maldistribution of gas flow, and inadequate heat transfer. It also covers mechanisms of catalyst deactivation like thermal sintering, chemical poisoning, and mechanical fouling. Overall, the document concisely outlines how to diagnose problems in catalytic reactors based on observable symptoms and their potential root causes.
Die materials and technique of fabricationAsa Yomi
This document discusses various materials and techniques used for fabricating dental dies. It describes common die materials like gypsum products, electroplated dies, epoxy resins, and ceramic materials. It outlines the basic requirements for die materials including the ability to reproduce fine detail, dimensional accuracy and stability, mechanical properties, and compatibility with impression materials. The document provides details on the manufacture and setting of gypsum products, the electroplating process for copper and silver dies, and the use of amalgam for die fabrication.
Molten salts corrode heat resistant alloys by dissolving the protective chromium oxide scale. Good performance of salt pots depends more on maintenance than alloy selection. Higher nickel alloys like 600 generally perform better than 309 or 330 in molten salt, but alloy choice is less important than proper maintenance to prevent salt contamination, oxygen buildup, and sludge accumulation.
1. The document discusses the scabbing defect that occurs in metal casting due to high temperatures in the mold material. At the entrance to the ingate, temperatures reach 1440°C, inducing compressive stresses on the mold surface that cause scabbing.
2. The study investigated modifying the ingate design to reduce turbulence in the molten metal flow and decrease heat transfer to the mold, which can relieve compressive stresses. The rectangular ingate profile was replaced with a gradually widening 60° profile to reduce sudden changes in cross-section.
3. Experimental results found that the modified ingate design decreased turbulence in the molten metal flow, transforming it from turbulent to more laminar. This reduced loosening of
This document provides information on constructing electrolyzers, which produce a mixture of hydrogen and oxygen gases ("hydroxy gas") through electrolysis of water. It describes three main types of electrolyzers: single cell units running off 12 volts, series connections of multiple 12 volt cells, and high-voltage series cells. Safety is the top priority, as hydroxy gas is highly explosive. Features like relays, circuit breakers, pressure release valves, and bubblers are recommended to minimize risks.
The document discusses various welding defects including lamellar tearing, porosity, underfill, insufficient
penetration, wagon tracks, arc strikes, and incomplete fusion. Lamellar tearing occurs beneath welds in rolled steel
plate and is caused by transverse strain from welding, a weld orientation parallel to inclusions, and poor material
ductility. Porosity is caused by absorbed gases like nitrogen, oxygen, and hydrogen which become trapped during
solidification. Prevention methods for defects include using proper joint design, welding techniques, materials, and
preheating when necessary. Defects require removal and rewelding to repair.
This document discusses the causes of rust bleeding in galvanized parts. Rust bleeding occurs when moisture and cleaning chemicals get trapped behind welds or in sealed areas during the galvanizing process. This can happen due to issues with venting trapped air out of enclosed welding areas, using stitch welds that leave gaps, or having pinholes in seal welds. While rust bleeding may appear to be the galvanizer's fault, the document explains that the root causes are usually design and fabrication choices rather than issues with the galvanizing process itself. The best solutions involve allowing gaps for zinc to fill during galvanizing or plugging rust bleeds after the fact.
This document provides instructions on how to solder electronic components onto printed circuit boards. It discusses:
- Soldering through-hole components which have leads that pass through holes in the board and are soldered to pads.
- Key steps including selecting the correct component, bending leads if needed, placing the soldering iron tip on the lead and pad to heat it, and feeding solder to create a joint.
- Tips like using flux-cored solder, cleaning copper soldering iron tips regularly, and wearing safety equipment due to heat and hazardous materials.
This experiment studied the precipitation hardening behavior of an Al-4%Cu alloy by measuring changes in hardness over time during artificial and natural aging. Artificial aging at 190°C produced maximum hardness after 10 minutes that decreased after 1 week as precipitates coarsened. Natural aging reached maximum hardness more slowly over 1 week. Maintaining the alloy at 190°C could lead to precipitate coarsening and hardness loss over time.
1. The maximum recommended kiln shell temperature varies significantly based on factors like the age of the kiln shell and refractory lining, thickness of the shell, distance between tires, and location of hot spots.
2. Hot spots indicate abnormally high temperatures under 600°C, while red spots that are visible at night always require action as they pose a greater risk of damage.
3. A red spot can generate significant stresses on the kiln shell due to the confined expansion, with a temperature difference of just 200°C potentially exceeding the steel's creep limit and nearing its ultimate strength.
EXPERIMENT 8 PRECIPITATION HARDENING IN 2024 ALUMINUM .docxSANSKAR20
EXPERIMENT 8
PRECIPITATION HARDENING IN 2024 ALUMINUM
Objective
To study the time and temperature variations in the hardness of Al-4% Cu alloy on
isothermal aging.
Introduction
Materials can be hardened by inhibiting the motion of crystal defects called dislocations. In
pure metals, the presence of defects (such as vacancies, interstitials, dislocations and grain
boundaries) can enhance the strength. In single phase alloys, additional resistance to
deformation may arise from the presence of foreign atoms. In two-phase alloys, additional
stress is needed to enable the dislocation to intersect the second-phase particles. A finely
dispersed precipitate may, therefore, strengthen the material. This phenomenon is termed
precipitation hardening.
The thermodynamics of precipitation in 2024 Al can best be understood by referring to the
binary phase diagram of Aluminum-Copper in the aluminum-rich region in Figure 8-1.
When the aluminum-copper alloy of less than 5 wt% copper is heated to a temperature just
above the solvus line, only one phase (kappa, ) is thermodynamically stable. Other solid
phases dissolve (disappear). This process is called solution treatment. The only requirement
is that the specimen must be kept at this temperature for a long enough time. To solution
treat a sample of 2024 Al (4 wt% Cu), the sample should be heated to 930°F (500°C) and held
for 30 minutes.
When a solution treated sample is rapidly cooled (quenched) to below the solvus line (Figure
8-1), two phases are thermodynamically stable (kappa and theta). These phases are two
different solids, physically distinct, and separated by a phase boundary. The process is
similar to precipitation of salt in supersaturated brine.
The process of precipitation is not instantaneous, as is often the case in liquid-solid
precipitation. The process involves the formation of embryos of theta through thermal
fluctuations and their subsequent growth, once they achieve stability. With time, more and
more precipitates form. This process is called aging. Once the solution achieves an
equilibrium composition given by the solvus line for the aging temperature, precipitation
stops. For example, the precipitation of the copper-rich theta phase depletes the kappa phase
of copper to approximately 1-1/2 wt% Cu at 715°F (380°C).
The distribution of precipitates affects the hardness and yield strength. The hardness and
yield strength are greater when the precipitates are small and finely dispersed in the kappa
matrix than when the precipitates are large and not finely scattered. Therefore, to gain
hardness in 2024 Al, the specimen should be heat treated to produce a fine dispersion of
small precipitates.
Unfortunately, there is a tendency when thermodynamic equilibrium is reached for large
precipitates to grow and small precipitates to shrink. This will lower the surface to volume
ratio of the precip ...
HOT ROLLING MILL - BILLETS Split ends and cracking problem ANIL KUMAR SHARMA
Several defects can occur during the metal rolling process. Surface defects such as impurities, scale, rust, or dirt are common if adequate surface preparation is not performed before rolling. More serious internal defects like edge cracks, center cracks, and wavy edges can result from improper material distribution in the final product. Other defects include alligatoring, where the material splits during rolling, and cracking or tearing from non-uniform heating of the workpiece in hot rolling. Process parameters like roll bending force, billet movement speed, roller clearance, and alloy composition can also influence defect formation.
Intro separate hydrogen and oxygen from water through electrolysisrahulchinoy
This document provides instructions for building a home electrolysis system to generate hydrogen and oxygen gases from water. It describes collecting the gases in plastic bottles by running electrolyzed water through the bottles. Electrodes made of braided wire and plastic sheeting are used to separate the hydrogen and oxygen during electrolysis when connected to a 6-12V battery power source. The generated gases can then be supplied to a vehicle engine through the fuel intake to potentially serve as an alternative to gasoline. Safety disclaimers are included as the instructions note the concept has not been built and tested by the author.
The document contains a copyright notice for materials from a physics textbook. It provides 13 multiple choice conceptual questions about thermal expansion and the behavior of materials when heated or cooled. The questions cover topics like the size of different temperature units, how mercury thermometers work, using thermal expansion to remove stuck items, and applications of the ideal gas law.
The material handling of the feedstock is a very critical part of the extrusion process. If the feedstock is not introduced to the feedsection of screw in a smooth and uniform matter, then the likelihood of a stable and consistent output is unlikely. This is the reason why it is very important that if regrind is added to the virgin feedstock, it must be done very consistently and uniformly. It should also be mentioned here that a very important part of the extrusion equipment is the hopper and feedthroat section. If the hopper and feedthroat sections are not designed properly, inconsistent material flow to the screw can take place. For example, if the conical section of the hopper (see figure) does not have the proper transition, the resin will not flow smoothly into the feedthroat of the extruder.
Physics 14 - Thermal properties and temperature - 1 2021-2022.pptxAlexandria Iskandar
The document discusses thermal expansion and temperature measurement. It describes how liquids in glass thermometers work, noting that liquids expand slightly when heated and this allows them to be used in thermometers. Thermometers are calibrated using two fixed points of 0°C and 100°C, defined as the melting and boiling points of water respectively. The scale is made linear by dividing the space between these points into 100 equal intervals called degrees. Common liquids used include mercury and ethanol, which have different measurable temperature ranges.
This document discusses various types of cracking that can occur in welds, including centerline cracking, heat affected zone cracking, and transverse cracking. It describes the causes and conditions required for each type of cracking, such as solidification processes, residual stresses, and hydrogen embrittlement. Prevention methods are also covered, like preheating materials, controlling hydrogen levels, and using filler metals designed to prevent cracking. The document provides detailed information on characterizing weld microstructures and properties to evaluate cracking tendencies.
Physical vapor deposition (PVD) involves evaporating or sputtering material from a source to deposit thin films on a substrate in a vacuum chamber. In evaporation, a thermal source heats material which travels in straight lines to the substrate. Sputtering uses plasma to bombard a target, ejecting atoms which deposit with better step coverage. Both techniques can deposit a wide range of materials but sputtering provides better step coverage and evaporation risks contamination.
Chapter - Thermal properties and temperature.pptxalokmishra1012
This document discusses various topics related to thermal properties of matter, including:
- Thermal expansion of solids, liquids and gases and its everyday applications.
- Measurement of temperature using properties that vary with temperature, such as liquid-in-glass thermometers which are calibrated using the fixed points of 0°C and 100°C.
- The relationship between gas pressure and temperature defined by the gas laws, where pressure and volume directly depend on temperature when other variables are held constant.
The document discusses the importance of teaching students how to learn effectively and efficiently. It states that students should be taught strategies for organizing information, retaining knowledge, and applying concepts rather than just memorizing facts. These skills will help students become independent, self-motivated learners who are able to continually acquire new information throughout their lives.
This document summarizes a lecture on micro heat pipes and cooling of microchips:
1) In microscale heat transfer devices, the wall thickness is small relative to the channel diameter, so heat conducted through the walls can significantly reduce the temperature difference driving heat transfer between fluids.
2) Cooling microchips effectively is challenging due to transient and three-dimensional heat generation across stacked chip layers. Placement of heat-generating components must consider both thermal management and electrical connections.
3) Micro heat pipes offer potential solutions but require accounting for enhanced wall conductivity, low Reynolds number laminar flows, and surface imperfections comparable to device dimensions.
The document discusses various types of discontinuities and defects that can occur in welding, including cracks, porosity, inclusions, insufficient penetration, and more. It defines discontinuities as interruptions in material structure that are not necessarily defects, while defects render a part unable to meet standards. Causes, preventions, and potential repairs are provided for each issue. Engineering problems can arise from design mistakes, while weld process issues relate to techniques and metallurgy.
Pitting corrosion is a localized form of corrosion that leads to the formation of small cavities or holes in the material. It occurs when small areas become active (anodic) while the surrounding areas remain passive (cathodic). This creates galvanic cells that drive the corrosion process. Pitting corrosion initiates at defects on the material surface and then propagates in an autocatalytic manner. It is most common in alloys protected by a passive film when exposed to environments containing chlorides, oxygen, and stagnant conditions. Proper material selection, surface finishing, controlling environmental factors like pH and chloride levels, and using protective coatings or cathodic protection can help prevent pitting corrosion.
6 methods of preparation of caustic sodarita martin
Sodium hydroxide, also known as caustic soda or lye, is an inorganic compound with the chemical formula NaOH. It is a white solid, and is a highly caustic metallic base and alkali salt. It is available in pellets, flakes, granules, and as prepared solutions at a number of different concentrations.
The document discusses various metal plating processes. It describes electroplating as coating metal onto another surface using electricity, where metal ions dissolve from the anode and deposit on the cathode. Electroless plating uses chemical reactions without electricity to deposit metal alloys like nickel-phosphorus. Galvanization coats iron or steel with zinc to prevent rusting. Post-plating processes like rinsing remove chemical residues. The electroplating industry generates various solid, liquid, and gaseous wastes that must be properly managed to reduce environmental pollution.
Physics 2.3 - Thermal properties and temperature - 1.pptxSilasSailasEndjala
This document discusses thermal properties and the measurement of temperature. It begins by describing the objectives of learning about thermal expansion of solids, liquids and gases, as well as methods of temperature measurement. Thermal expansion is then explained, noting that heating causes the particles in solids, liquids and gases to move more, taking up more space. Everyday examples of thermal expansion like bridges and planes are provided. Methods of temperature measurement like liquid-in-glass thermometers and their calibration are then summarized. Key concepts in gases like Charles' law relating volume and temperature are also highlighted at a high level.
This document provides instructions on how to solder electronic components onto printed circuit boards. It discusses:
- Soldering through-hole components which have leads that pass through holes in the board and are soldered to pads.
- Key steps including selecting the correct component, bending leads if needed, placing the soldering iron tip on the lead and pad to heat it, and feeding solder to create a joint.
- Tips like using flux-cored solder, cleaning copper soldering iron tips regularly, and wearing safety equipment due to heat and hazardous materials.
This experiment studied the precipitation hardening behavior of an Al-4%Cu alloy by measuring changes in hardness over time during artificial and natural aging. Artificial aging at 190°C produced maximum hardness after 10 minutes that decreased after 1 week as precipitates coarsened. Natural aging reached maximum hardness more slowly over 1 week. Maintaining the alloy at 190°C could lead to precipitate coarsening and hardness loss over time.
1. The maximum recommended kiln shell temperature varies significantly based on factors like the age of the kiln shell and refractory lining, thickness of the shell, distance between tires, and location of hot spots.
2. Hot spots indicate abnormally high temperatures under 600°C, while red spots that are visible at night always require action as they pose a greater risk of damage.
3. A red spot can generate significant stresses on the kiln shell due to the confined expansion, with a temperature difference of just 200°C potentially exceeding the steel's creep limit and nearing its ultimate strength.
EXPERIMENT 8 PRECIPITATION HARDENING IN 2024 ALUMINUM .docxSANSKAR20
EXPERIMENT 8
PRECIPITATION HARDENING IN 2024 ALUMINUM
Objective
To study the time and temperature variations in the hardness of Al-4% Cu alloy on
isothermal aging.
Introduction
Materials can be hardened by inhibiting the motion of crystal defects called dislocations. In
pure metals, the presence of defects (such as vacancies, interstitials, dislocations and grain
boundaries) can enhance the strength. In single phase alloys, additional resistance to
deformation may arise from the presence of foreign atoms. In two-phase alloys, additional
stress is needed to enable the dislocation to intersect the second-phase particles. A finely
dispersed precipitate may, therefore, strengthen the material. This phenomenon is termed
precipitation hardening.
The thermodynamics of precipitation in 2024 Al can best be understood by referring to the
binary phase diagram of Aluminum-Copper in the aluminum-rich region in Figure 8-1.
When the aluminum-copper alloy of less than 5 wt% copper is heated to a temperature just
above the solvus line, only one phase (kappa, ) is thermodynamically stable. Other solid
phases dissolve (disappear). This process is called solution treatment. The only requirement
is that the specimen must be kept at this temperature for a long enough time. To solution
treat a sample of 2024 Al (4 wt% Cu), the sample should be heated to 930°F (500°C) and held
for 30 minutes.
When a solution treated sample is rapidly cooled (quenched) to below the solvus line (Figure
8-1), two phases are thermodynamically stable (kappa and theta). These phases are two
different solids, physically distinct, and separated by a phase boundary. The process is
similar to precipitation of salt in supersaturated brine.
The process of precipitation is not instantaneous, as is often the case in liquid-solid
precipitation. The process involves the formation of embryos of theta through thermal
fluctuations and their subsequent growth, once they achieve stability. With time, more and
more precipitates form. This process is called aging. Once the solution achieves an
equilibrium composition given by the solvus line for the aging temperature, precipitation
stops. For example, the precipitation of the copper-rich theta phase depletes the kappa phase
of copper to approximately 1-1/2 wt% Cu at 715°F (380°C).
The distribution of precipitates affects the hardness and yield strength. The hardness and
yield strength are greater when the precipitates are small and finely dispersed in the kappa
matrix than when the precipitates are large and not finely scattered. Therefore, to gain
hardness in 2024 Al, the specimen should be heat treated to produce a fine dispersion of
small precipitates.
Unfortunately, there is a tendency when thermodynamic equilibrium is reached for large
precipitates to grow and small precipitates to shrink. This will lower the surface to volume
ratio of the precip ...
HOT ROLLING MILL - BILLETS Split ends and cracking problem ANIL KUMAR SHARMA
Several defects can occur during the metal rolling process. Surface defects such as impurities, scale, rust, or dirt are common if adequate surface preparation is not performed before rolling. More serious internal defects like edge cracks, center cracks, and wavy edges can result from improper material distribution in the final product. Other defects include alligatoring, where the material splits during rolling, and cracking or tearing from non-uniform heating of the workpiece in hot rolling. Process parameters like roll bending force, billet movement speed, roller clearance, and alloy composition can also influence defect formation.
Intro separate hydrogen and oxygen from water through electrolysisrahulchinoy
This document provides instructions for building a home electrolysis system to generate hydrogen and oxygen gases from water. It describes collecting the gases in plastic bottles by running electrolyzed water through the bottles. Electrodes made of braided wire and plastic sheeting are used to separate the hydrogen and oxygen during electrolysis when connected to a 6-12V battery power source. The generated gases can then be supplied to a vehicle engine through the fuel intake to potentially serve as an alternative to gasoline. Safety disclaimers are included as the instructions note the concept has not been built and tested by the author.
The document contains a copyright notice for materials from a physics textbook. It provides 13 multiple choice conceptual questions about thermal expansion and the behavior of materials when heated or cooled. The questions cover topics like the size of different temperature units, how mercury thermometers work, using thermal expansion to remove stuck items, and applications of the ideal gas law.
The material handling of the feedstock is a very critical part of the extrusion process. If the feedstock is not introduced to the feedsection of screw in a smooth and uniform matter, then the likelihood of a stable and consistent output is unlikely. This is the reason why it is very important that if regrind is added to the virgin feedstock, it must be done very consistently and uniformly. It should also be mentioned here that a very important part of the extrusion equipment is the hopper and feedthroat section. If the hopper and feedthroat sections are not designed properly, inconsistent material flow to the screw can take place. For example, if the conical section of the hopper (see figure) does not have the proper transition, the resin will not flow smoothly into the feedthroat of the extruder.
Physics 14 - Thermal properties and temperature - 1 2021-2022.pptxAlexandria Iskandar
The document discusses thermal expansion and temperature measurement. It describes how liquids in glass thermometers work, noting that liquids expand slightly when heated and this allows them to be used in thermometers. Thermometers are calibrated using two fixed points of 0°C and 100°C, defined as the melting and boiling points of water respectively. The scale is made linear by dividing the space between these points into 100 equal intervals called degrees. Common liquids used include mercury and ethanol, which have different measurable temperature ranges.
This document discusses various types of cracking that can occur in welds, including centerline cracking, heat affected zone cracking, and transverse cracking. It describes the causes and conditions required for each type of cracking, such as solidification processes, residual stresses, and hydrogen embrittlement. Prevention methods are also covered, like preheating materials, controlling hydrogen levels, and using filler metals designed to prevent cracking. The document provides detailed information on characterizing weld microstructures and properties to evaluate cracking tendencies.
Physical vapor deposition (PVD) involves evaporating or sputtering material from a source to deposit thin films on a substrate in a vacuum chamber. In evaporation, a thermal source heats material which travels in straight lines to the substrate. Sputtering uses plasma to bombard a target, ejecting atoms which deposit with better step coverage. Both techniques can deposit a wide range of materials but sputtering provides better step coverage and evaporation risks contamination.
Chapter - Thermal properties and temperature.pptxalokmishra1012
This document discusses various topics related to thermal properties of matter, including:
- Thermal expansion of solids, liquids and gases and its everyday applications.
- Measurement of temperature using properties that vary with temperature, such as liquid-in-glass thermometers which are calibrated using the fixed points of 0°C and 100°C.
- The relationship between gas pressure and temperature defined by the gas laws, where pressure and volume directly depend on temperature when other variables are held constant.
The document discusses the importance of teaching students how to learn effectively and efficiently. It states that students should be taught strategies for organizing information, retaining knowledge, and applying concepts rather than just memorizing facts. These skills will help students become independent, self-motivated learners who are able to continually acquire new information throughout their lives.
This document summarizes a lecture on micro heat pipes and cooling of microchips:
1) In microscale heat transfer devices, the wall thickness is small relative to the channel diameter, so heat conducted through the walls can significantly reduce the temperature difference driving heat transfer between fluids.
2) Cooling microchips effectively is challenging due to transient and three-dimensional heat generation across stacked chip layers. Placement of heat-generating components must consider both thermal management and electrical connections.
3) Micro heat pipes offer potential solutions but require accounting for enhanced wall conductivity, low Reynolds number laminar flows, and surface imperfections comparable to device dimensions.
The document discusses various types of discontinuities and defects that can occur in welding, including cracks, porosity, inclusions, insufficient penetration, and more. It defines discontinuities as interruptions in material structure that are not necessarily defects, while defects render a part unable to meet standards. Causes, preventions, and potential repairs are provided for each issue. Engineering problems can arise from design mistakes, while weld process issues relate to techniques and metallurgy.
Pitting corrosion is a localized form of corrosion that leads to the formation of small cavities or holes in the material. It occurs when small areas become active (anodic) while the surrounding areas remain passive (cathodic). This creates galvanic cells that drive the corrosion process. Pitting corrosion initiates at defects on the material surface and then propagates in an autocatalytic manner. It is most common in alloys protected by a passive film when exposed to environments containing chlorides, oxygen, and stagnant conditions. Proper material selection, surface finishing, controlling environmental factors like pH and chloride levels, and using protective coatings or cathodic protection can help prevent pitting corrosion.
6 methods of preparation of caustic sodarita martin
Sodium hydroxide, also known as caustic soda or lye, is an inorganic compound with the chemical formula NaOH. It is a white solid, and is a highly caustic metallic base and alkali salt. It is available in pellets, flakes, granules, and as prepared solutions at a number of different concentrations.
The document discusses various metal plating processes. It describes electroplating as coating metal onto another surface using electricity, where metal ions dissolve from the anode and deposit on the cathode. Electroless plating uses chemical reactions without electricity to deposit metal alloys like nickel-phosphorus. Galvanization coats iron or steel with zinc to prevent rusting. Post-plating processes like rinsing remove chemical residues. The electroplating industry generates various solid, liquid, and gaseous wastes that must be properly managed to reduce environmental pollution.
Physics 2.3 - Thermal properties and temperature - 1.pptxSilasSailasEndjala
This document discusses thermal properties and the measurement of temperature. It begins by describing the objectives of learning about thermal expansion of solids, liquids and gases, as well as methods of temperature measurement. Thermal expansion is then explained, noting that heating causes the particles in solids, liquids and gases to move more, taking up more space. Everyday examples of thermal expansion like bridges and planes are provided. Methods of temperature measurement like liquid-in-glass thermometers and their calibration are then summarized. Key concepts in gases like Charles' law relating volume and temperature are also highlighted at a high level.
Similar to Discussion of ledge profile in a Vertical Stud Soderberg aluminum reduction cell. (20)
Generator parameters graphs, showing various instabilities.. Gary L Gordon
Graph and data retrieved using data loggers. Shows basic engine and AC parameters Some discussion of possible generator dependability coming in the future.
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Harness the power of AI-backed reports, benchmarking and data analysis to predict trends and detect anomalies in your marketing efforts.
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Industry: Areas of commercial application for AI and its business impact.
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Safety: Identifying and mitigating catastrophic risks that highly-capable future AI systems could pose to us.
Predictions: What we believe will happen in the next 12 months and a 2022 performance review to keep us honest.
Discussion of ledge profile in a Vertical Stud Soderberg aluminum reduction cell.
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LEDGE PROFILE
There is a need for our ledge and muck measuring to be less subjective. We need to understand what
the ledge should be like and use the same terminology.
Our ledge usually looks similar to the 2 examples
here, having too much toe, and not enough saddle,
or too much ledge period.
The first example shows a sloped ledge that allows
undissolved ore to slide below the metal/bath
interface. The will require additional power clean
the pot bottom.
The second example shows a high hard ledge. This
condition will reflect heat back up the anode. This
additional heat will raise the bake zone. This will be manifest by a wet/hot top. If this condition is left
unchecked it will quite possibly result in spikes and/or shatter.
If a probing rod is inserted at a 45° it will not
touch bottom block, in either case. A technician
measuring rod will rest on the saddle also.
Ratio control will play a key role in ledge shape.
A low ratio pot will usually have a larger ledge,
while a high ratio will generally have a smaller
ledge. As the ledge grows upward it gets close
to the anode, there will be a decrease in heat
flow out the sidewall. A considerable amount of
this heat will be reflected back up in to the
anode, visibly heating the anode top. There will be considerable disruption to the bake zone. This can
cause spikes and or shatter a few weeks later. Normally anode/ledge clearance would be greater than
6”
However an overlooked contributing factor is the change
in ratio. If the ratio is allowed to drift up, at some point it
will have to be driven back to acceptable levels. If we
imagine the bath as a large motel, with the rooms being
cube shaped. When the ratio and temperature are elevated
the rooms expand. Each room is occupied by chemicals in
the bath. As we drive the ratio and temperature back to
accepted levels these motel rooms start to shrink. These
rooms shrink until there isn’t enough space for the excess
material. The bath kicks out carbon dust which floats and
we remove, but this is not the only particles suspended in
the bath. Other material sinks to the bottom making a
coating similar to freshly fallen snow. If this muck left to its own devices it will become an extended
toe or some carborundum looking material, we refer to as alligators.
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The advent of the technology to actually measure the super
heat has improved the ratio control. However the superheat
is greatly influenced by ore concentration. Without
knowing the actual ore concentration you can not know the
ratio. Regular ratio test are still required.
The next sequence of pictures shows the development of
the large front ledges, alligators.
There will always be a tail of undissolved ore at the foot of
the ledge. There will also be ledge material that has
slumped over and covers some of the tail material. If there
is enough material this tail, it will become a weak spot that
helps the formation of the high hard hump out in the center
of the cathode.
As the ratio gets out of control again, this same sequence
of events will happen repeatedly and layer after layer will
be deposited on the cathode floor until it reaches the metal
bath interface. Once the material reaches the liquid bath it
will be dissolved into solution. Even the hard muck or
alligators will not exist for a long period when exposed to
liquid bath.
If the pot can be run at a stable condition for a reasonable
length of time, the cathode will start to clean out. This
material will change the ratio as it dissolves. This can reek
havoc with ratio control and cause the formation of more
layers.
One of the thinnest places, and therefore first to break
through, will be the area that covers the undissolved ore at
the base of the original ledge. Gradually that undissolved
ore will be brought into solution and made into metal.
When that tail of ore is gone you can feel the bottom blocks
at the base of the ledge. But out a few more inches you will
find the mound, of hard muck, that is left over from the
BIG ledge.
The normal swirl of the metal pad and amperage flow will
erode some of the softer material. However the hard
alligator material usually requires mechanical help, such as
stirring with a tapper’s skid steer, a regular rake, or pine
pole therapy. Another way to clean these pot bottoms was
raising the ratio slightly to 1.18 and adding .10 - .20 volts.
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It is critical to maintain a ratio slightly higher but it must not be allowed to reach 1.20. The faster the
ratio is moved down the more material will fall to the cathode floor. The voltage would be reduced
first. Then the ratio would be gradually brought to 1.14.
The proper ledge profile would be similar to the one pictured below, left. Beyond the saddle, this ledge
drops off rather steeply. This ledge doesn’t
encroach under the anode shadow very far.
Another benefit to this profile would be somewhat
better control of the metal pad movement. There
isn’t a gradual slope for the metal ride up and
eventually contact the anode and be reoxidized,
reducing current efficiency.
For optimal Cathode Voltage Drop the ledge
should look more like this. With a probing rod at
45° angle it should not contact any part of the
ledge. The ledge should not extend under the
shadow of the anode, more than 4”-5”. The pot also requires a minimum of 6” clearance between the
corner of the anode and the edge of the ledge.
There is no need for ledge behind the skirt, not
much material will be drifting into the bath and/or
onto the top of the ledge from this area.
The two areas that need work are the saddle and
the extended toe. More Rand Breaks will help
define the saddle portion, while Amperage, and
metal pad movement, will erode the lower ledge.
There would always be a small toe of muck at the
base of the ledge.
Occasionally there will be material buried in the ledge
that is not really high ratio bath. If a crustbreaker bit, or
tapper’s paddle bit breaks in the pot, rarely can they be
recovered. It sinks into the soft lower ledge, where it will
become part of the ledge. The broken bit will likely be
uncovered by bath action at some later date, giving an
unexplainable increase in iron.
You can see the fluoride and breaker bit both
encapsulated inside the bath in these 2 illustrations
Another situation would be, when the pot is sick. The
ledge has usually receded and the fluoride consumption is
high. Sometimes the raw fluoride is not dissolved and settles out of the bath. It can pile up on the
saddle of the ledge, below the metal pad level. Later as the pot starts to heal, ledge can form over
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whatever is deposited on the ledge surface. It will be uncovered at some later date. Perhaps a long
light will melt some ledge and expose a large clump of fluoride that will drop the ratio.
Soda Ash will probably not be deposited in the ledge
due to its immediate reaction to the bath.
Hopefully this will help in understanding how the pot
chemistry can move in unexpected directions, at
unexpected times.
Our original thinking was that the ledge was formed in
layers, with the higher ratio material next to the cathode
carbon. Newer testing has indicated that the ledge
material is more homogenous, being 1.25 ratio
throughout.
A cathode consultant was hired to study block
erosion. His recommendation was that the ledge
should extend approximately 12” under the anode
shadow, to inhibit cathode erosion. As seen in the
drawing at right, a rod inserted at 45° angle would
still contact blocks rather than ledge.
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Measuring the Ledge
There are 3 easily measurable values for the ledge First
measure how far down to the saddle. This dimension should be
somewhat more than the bath measurement. The top of the
saddle should be at approximately the lowest metal pad
elevation. Ledge material is frozen bath. It is covered by
metal. As soon as it is exposed to liquid bath it will start to
dissolve. This is the reason the saddle will be near the lowest
metal pad elevation. There are a lot of ledges at CFAC where
the saddle extends out under the anode. This will greatly effect
the clearance measured in the next drawing.
The second parameter that is measurable would be the
clearance between the anode corner and the ledge. Pivot a probe or small muck rake and estimate the
room. An anode needs a minimum of 6” clearance or it will
generate heat that will result in carbon dust, spikes and/or
shatter.
The saddle should be at the lowest elevation of the metal
pad. Liquid bath will dissolve any ledge material that
protrudes up out of the metal in a few hours. This is part of
the reason anode effect (light) frequency goes down after
metal tap. Ledge or ore are slowly pulled into solution after
the metal tap uncovers them.
As the saddle grows higher and farther out toward the anode
it is recorded as slightly extended or extended. If the
metal/bath measuring rod is inserted and the tip rests on ledge, the ledge is indeed slightly extended or
extended. If the ledge extends out under the anode, the ledge will be very near the anode after tap.
This is referred to as sitting the anode on the ledge. The anode doesn’t have to actually touch the ledge
it just needs to be closer than 6”.
The extension of the toe is measurable from the skirt to the
end of the ledge. We can use an inclinometer or measure the
diagonal and use the Pythagorean theorem to calculate the
extension. Refer to the ledge extension document, for a better
explanation. An extended ledge will limit the ability of
electrons to flow from the cathode carbon into the metal pad.
This will increase the resistance which translates into voltage,
and simply costs more money. The lower ledge is not really
used in determining the recorded size of the ledge.
The next figure shows 5 ledge profiles. When the feed
schedule breaks most of the material is outside the skirt,
there isn’t much need for ledge inside the skirt since a
minimal amount of material settles into the bath that far from the ore rail. The second panel shows a
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45° angle and a vertical line approximating the “shadow of the anode”. The second panel also shows
the approximate shape of the ledge that would slow the metal pad movement to minimize cathode
block erosion. The forth panel is a fairly large ledge, this size of ledge is actually viewable in freshly
tapped down cut out pots. Many front ledges are like this. The fifth panel shows the proximity of the
anode and an extended ledge after metal tap.
The anode directly above the ledge will be weakened from being this close to the ledge. Weaker
carbon will crumble and fall loose as shatter. Stronger anode carbon will probably exhibit more
spiking, since it won’t crumble. These problems are mostly related to uneven heat distribution inside
the lower portion of the anode.
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Actual measurement of ledge extension.
This table shows the reduction in available surface area relative to actual anode surface area. A cathode
actually has a larger surface, but it is covered by ledge.
.
Anode is 21'-7.5" X 7'-10" (21.625 feet X 7.833 feet).
The Urata document wants 12" ledge extension under the anode shadow
If we add an additional 6" extension under the anode.
shadow Urata extended actual
length 21.625 19.625 18.625 17.625
width 7.833 5.833 4.833 3.833
169.39 sq ft 114.47 sq ft 90.015 sq ft 67.557 sq ft
Area lost to electric conductivity, covered by extended ledge.
54.916 sq ft 79.374 sq ft 101.83 sq ft
Percent of original anode shadow area.
100 % 67.58 % 53.141 % 39.883 %
Percent reduction in available surface area
0 % 32.42 % 46.859 % 60.117 %
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Todd, has supplied the following chart, that shows the increase in Cathode Voltage Drop opposed to
cathode coverage.
Open Cathode Face Vs CVD
0
2
4
6
8
10
12
14
16
18
350 355 360 365 370 375 380 385 390 395 400
CVD
PredictedSquareMeters
low high OurSpec
The following table demonstrates our ledge extension, measured by the above method. Cavity depth
was calculated by Justin Hipple. Diagonal was actually measured. Anodes are 7’-10” wide. If we
actually have ~24” of ledge protruding under the front and back the cathode surface area is now only
3’-10” wide
Measurement of actual protrusion of the ledge under the anode. Diagonal is actual measurement
from edge of skirt to bottom block. Horizontal extension is then from edge of skirt to
Data acquired in room7 5-8-07 and 5-9-07 average temp was 972 °
pot Cavity diag horiz minus 60 pot
Pot age depth length extension 9" average
701 2606 26 42 32.98 23.98 25.13
702 2200 26 46 37.95 28.95
703 2760 26 44 35.50 26.50
704 2986 26 40 30.40 21.40
705 472 24 50 43.86 34.86
706 3242 26 40 30.40 21.40
707 3603 28 48 38.99 29.99
708 3633 28 42 31.30 22.30
709 4067 28 51 42.63 33.63
710 243 26 40 30.40 21.40
711 2312 26 40 30.40 21.40
712 1246 26 40 30.40 21.40