Carbon nanotubes are allotropes of carbon that exist as cylindrical structures with a high length-to-diameter ratio. They can be single-walled or multi-walled depending on the number of concentric cylinders. Carbon nanotubes have extraordinary properties including high strength, stiffness, thermal conductivity, and electrical conductivity. Due to these properties, carbon nanotubes show promise for applications in electronics, hydrogen storage, solar cells, biosensors, drug delivery, and more.
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
Nano Material
Introduction and Synthesis
Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 and 1000 nanometres (10−9 meter) but is usually 1—100 nm (the usual definition of nanoscale[1]).
Nanomaterials research takes a materials science-based approach to nanotechnology, leveraging advances in materials metrology and synthesis which have been developed in support of microfabrication research. Materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties.
Nanomaterials are slowly becoming commercialized[2] and beginning to emerge as commodities.[3]
The following presentation is only for quick reference. I would advise you to read the theoretical aspects of the respective topic and then use this presentation for your last minute revision. I hope it helps you..!!
Mayur D. Chauhan
here you can find the most rare topics in detail
all fields of chemistry are deeply understood here for presenting the lectures
stay blessed and keep supporting
know more about nanomaterials and its apllication in future as well as current situation, and what wil we reserch on basis of nanomaterials and carbon structure and its aplication in such futuriastic manner.
Nano Material
Introduction and Synthesis
Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 and 1000 nanometres (10−9 meter) but is usually 1—100 nm (the usual definition of nanoscale[1]).
Nanomaterials research takes a materials science-based approach to nanotechnology, leveraging advances in materials metrology and synthesis which have been developed in support of microfabrication research. Materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties.
Nanomaterials are slowly becoming commercialized[2] and beginning to emerge as commodities.[3]
The following presentation is only for quick reference. I would advise you to read the theoretical aspects of the respective topic and then use this presentation for your last minute revision. I hope it helps you..!!
Mayur D. Chauhan
here you can find the most rare topics in detail
all fields of chemistry are deeply understood here for presenting the lectures
stay blessed and keep supporting
know more about nanomaterials and its apllication in future as well as current situation, and what wil we reserch on basis of nanomaterials and carbon structure and its aplication in such futuriastic manner.
Icarus design is a Design firm offering services in Industrial design and Branding.
We have been working on several socially relevant projects that we wish to upload here.
These projects are in progress and we are looking for people or organisations to collaborate for this development.
Carbon nanotube is an allotrope of carbon and it is widely used in many Research and Development companies. The presentation will help students to get some idea on this topic.
New technology Model for 1 nm Transistors better than FIN-FET Technology.This slide Tells you in general about the nanotubes, how they are formed and why they are better than MOSFETs
This presentation provides a comprehensive and in-depth exploration of Carbon Nanotubes, beginning with the foundational principles and advancing to more complex concepts. Its purpose is to offer a student-oriented elucidation of this subject matter. This PowerPoint presentation serves as a highly valuable tool for undergraduate students pursuing Nanoelectronics, as it encompasses all the crucial aspects of Carbon Nanotubes, facilitating a clear understanding of the topic.
Network embedding in biomedical data scienceArindam Ghosh
Excerpts from the paper:
What is it?
Network embedding aims at converting the network into a low-dimensional space while structural information of the network is preserved.
In this way, nodes and/or edges of the network can be represented as compacted yet informative vectors in the embedding space.
Advantages:
Typical non-network-based machine learning methods such as linear regression, Support Vector Machine (SVM) and decision forest, which have been demonstrated to be effective and efficient as the state-of-the-art techniques, can be applied to such vectors.
Current status:
Efforts of applying network embedding to improve biomedical data analysis are already planned or underway.
Difficulties:
The biomedical networks are sparse, noisy, incomplete, heterogeneous and usually consist of biomedical text and other domain knowledge. It makes embedding tasks more complicated than other application fields.
Sequencing is one of the major technological advancement that has taken shape in the last two or three decade. Starting from Sanger and Maxam-Gilbert sequencing methods to the latest high-throughput methods, sequencing technologies has changed the the landscape of biological sciences.
This slide takes a look a the major sequencing methods over time.
Note: Several images included here have been sourced from GOOGLE IMAGES. The content has been extracted from several SCIENTIFIC PAPERS and WEBSITES.
PLEASE DO CONTACT THE AUTHOR DIRECTLY IF ANY COPYRIGHT ISSUE ARISES.
Humans are 99% similar to each other; but it is the 1% that is the cause of concern. This relatively small difference actually how a drug will effect our body. Pharmacogenomics is the study of how genes affect a person’s response to drugs. In order to prevent any unwanted reactions it has become necessary to consider one's genome while prescribing medicine. Thus pharmacogenomics is the starting point of personalized medicine.
Ab Initio Protein Structure Prediction is a method to determine the tertiary structure of protein in the absence of experimentally solved structure of a similar/homologous protein. This method builds protein structure guided by energy function.
I had prepared this presentation for an internal project during my masters degree course.
Deodar has been given the status of State plant in the Indian state of Himachal Pradesh rightly due to its presence in abundance in the state. The tree belongs to the genus cedrus. This presentation tries to explore the different species of cedrus found worldwide, the regions they are found, uses, conservation status etc.
Note: The images used as background in each slide belongs to the author.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2. Carbon nanotubes (CNTs) are
an allotrope of carbon.
Allotrope: each of two or more different physical forms in
which an element can exist.
3.
4. ● CNTs are long, thin cylinders of carbon.
● They can be thought of as a sheet of graphite (a hexagonal
lattice of carbon) rolled into a cylinder.
● Nanotubes have been constructed with length-to-diameter ratio
of up to 132,000,000:1.
CNTs were discovered in 1991 by Sumio Iijima
6. The structure of a carbon nanotube is formed by a layer of
carbon atoms that are bonded together in a hexagonal
(honeycomb) mesh. This one-atom thick layer of carbon is
called graphene, and it is wrapped in the shape of a cylinder
and bonded together to form a carbon nanotube.
Fig.: Graphene
7. Nanotubes can have a single outer wall of carbon, or they
can be made of multiple walls (cylinders inside other
cylinders of carbon). Accordingly they are called:
– Single-walled carbon nanotube
– Multi-walled carbon nanotube
8. Single-walled carbon nanotube structure
● Single-walled carbon nanotubes can be formed in three
different designs: Armchair, Chiral, and Zigzag.
● The design depends on the way the graphene is wrapped
into a cylinder.
9. Multi-walled carbon nanotube structure
● There are two structural models of multi-walled nanotubes:
– Russian Doll model
– Parchment model
10. ● In the Russian Doll model, a carbon nanotube contains
another nanotube inside it (the inner nanotube has a
smaller diameter than the outer nanotube).
11. ● In the Parchment model, a single graphene sheet is rolled
around itself multiple times, resembling a rolled up scroll
of paper.
12. SWCNT vs MWCNT
● MWCNTs have similar properties to SWCNTs.
● The outer walls on MWCNTs can protect the inner carbon
nanotubes from chemical interactions with outside
materials.
● MWCNTs also have a higher tensile strength than SCNTs.
15. Arc Discharge method
● First method successfully used to synthesize CNTs in small
quantities
● Opposing anode and cathode terminals made of 6-mm and 9-
mm graphite rods respectively are placed in an inert
environment (He or Ar at ~500 Torr). A strong current,
typically around 100 A (DC or AC), is passed between the
terminals generating arc-induced plasma that evaporates the
carbon atoms in the graphite. The nanotubes grow from the
surface of these terminals.
● A catalyst can be introduced into the graphite terminal.
● Although MWNTs can be formed without a catalyst, it has
been found that SWNTs can only be formed with the use of a
metal catalyst such as iron or cobalt.
17. Laser Ablation
● First developed in 1995.
● Uses a similar principle as Arc Discharge method.
● Carbon is evaporated at high temperatures from a graphite
target using a powerful and focused laser beam.
● In the most basic laser ablation technique, a 1.25-cm
diameter graphite target is placed in a 2.5-cm diameter, 50-
cm long quartz tube in a furnace controlled at 1200°C and
filled with 99.99% pure argon to a pressure of 500 Torr. A
pulsed Nd:Yag laser beam at 250mJ (10 Hz) is focused
using a circular lens and the beam is swept uniformly across
the graphite target surface. The nanotubes, mixed with
undesired amorphous carbon, are collected on a cooled
substrate at the end of the chamber.
19. Both of these methods have limited potential for scale-up.
Solid graphite must be evaporated at >3000°C to source the
carbon needed, the nanotubes produced are in an entangled
form, and extensive purification is required to remove the
amorphous carbon and fullerenes that are naturally produced in
the process.
20. Chemical Vapor Deposition (CVD)
● CVD has the highest potential for mass production of carbon
nanotubes.
● It can produce bulk amounts of defect-free CNTs at relatively
low temperatures.
● Method:
➔ A substrate material (e.g. alumina, quartz), is cleaned in
preparation for the catalyst deposition.
➔ A porous substrate may be desired, so electrochemical
etching with a hydrofluoric acid/methanol solution may be
performed. Nanotubes can grow at a higher rate on a porous
substrate, suggesting that carbon can diffuse through the
porous substrate layer and feed growing nanotubes.
21. ➔ A catalyst (e.g. iron, nickel) is deposited onto the
substrate by thermal evaporation.
➔ The furnace is raised to a temperature between 500-
1200°C and a hydrocarbon gas such as acetylene,
ethylene, or carbon monoxide is slowly pumped into the
reactor. At these high temperatures carbon dissociates
from the feedstock molecules and diffuses onto the
catalyst.
➔ The atoms arrange themselves into a sheet of nanotubes
on the substrate, combined with impurities such as
amorphous carbon, fullerenes, as well as the catalyst
material.
➔ In most cases these impurities must be removed using a
purification step. An acid treatment followed by
sonification is popular.
23. Strength
● Carbon nanotubes have a higher tensile strength than steel
and Kevlar.
● The strength comes from the sp² bonds between the
individual carbon atoms. This bond is even stronger than the
sp³ bond found in diamond.
● Under high pressure, individual nanotubes can bond
together, trading some sp² bonds for sp³ bonds. This gives
the possibility of producing long nanotube wires.
24. ● Carbon nanotubes are not only strong, they are also elastic.
One can press on the tip of a nanotube and cause it to bend
without damaging to the nanotube, and the nanotube will
return to its original shape when the force is removed.
● A nanotube's elasticity does have a limit, and under very
strong forces, it is possible to permanently deform to shape
of a nanotube.
25. ● A nanotube’s strength can be weakened by defects in the
structure of the nanotube.
● Defects occur from atomic vacancies or a rearrangement of
the carbon bonds. Defects in the structure can cause a small
segment of the nanotube to become weaker, which in turn
causes the tensile strength of the entire nanotube to weaken.
● The tensile strength of a nanotube depends on the strength
of the weakest segment in the tube similar to the way the
strength of a cahin depends on the weakest link in the chain.
26. Hardness
● Standard single-walled carbon nanotubes can withstand a
pressure up to 25 GPa without [plastic/permanent]
deformation. They then undergo a transformation to
superhard phase nanotubes.
● Maximum pressures measured using current experimental
techniques are around 55 Gpa.
● However, these new superhard phase nanotubes collapse at
an even higher, albeit unknown, pressure.
● The bulk modulus of superhard phase nanotubes is 462 to
546 GPa, even higher than that of diamond (420 GPa for
single diamond crystal).
27. Electrical properties
● The structure of a carbon nanotube determines how
conductive the nanotube is.
● When the structure of atoms in a carbon nanotube
minimizes the collisions between conduction electrons and
atoms, a carbon nanotube is highly conductive.
● The strong bonds between carbon atoms also allow carbon
nanotubes to withstand higher electric currents than copper.
● Electron transport occurs only along the axis of the tube.
● Single walled nanotubes can route electrical signals at
speeds up to 10 GHz when used as interconnects on semi-
conducting devices.
● Nanotubes also have a constant resistivity.
28. Thermal Properties
● The strength of the atomic bonds in carbon nanotubes
allows them to withstand high temperatures. Because of
this, carbon nanotubes have been shown to be very good
thermal conductors.
● When compared to copper wires, which are commonly used
as thermal conductors, the carbon nanotubes can transmit
over 15 times the amount of watts per meter per Kelvin.
● The thermal conductivity of carbon nanotubes is dependent
on the temperature of the tubes and the outside environment.
29. Wettability
● The surface wettability of CNT is of importance for its
applications in various settings.
● Although the intrinsic contact angle of graphite is around
90°, the contact angles of most as-synthesized CNT arrays
are over 160°, exhibiting a superhydrophobic property.
● By applying a low voltage as low as 1.3V, the extreme water
repellant surface can be switched into superhydrophilic.
30. Field Emission
● Under the application of strong electric field, tunneling of
electrons from metal tip to vacuum results in field emission
phenomenon.
● Field emission results from the high aspect ratio and small
diameter of CNTs.
● The field emitters are suitable for the application in flat-
panel displays.
● For MWNTs, the field emission properties occur due to the
emission of electrons and light.
● Without applied potential, the luminescence and light
emission occurs through the electron field emission and
visible part of the spectrum, respectively.
31. Aspect Ratio
● One of the exciting properties of CNTs is the high aspect
ratio, inferring that a lower CNT load is required compared
to other conductive additives to achieve similar electrical
conductivity.
● The high aspect ratio of CNTs possesses unique electrical
conductivity in comparison to the conventional additive
materials such as chopped carbon fiber, carbon black, or
stainless steel fiber.
32. Absorbent
● Carbon nanotubes and CNT composites have been emerging
as perspective absorbing materials due to their light weight,
larger flexibility, high mechanical strength and superior
electrical properties.
● CNTs emerge out as ideal candidate for use in gas, air and
water filtration.
● The absorption frequency range of SWNT-polyurethane
composites broaden from 6.4–8.2 (1.8 GHz) to 7.5–10.1
(2.6 GHz) and to 12.0–15.1 GHz (3.1 GHz) (Wang et al.
2013).
● A lot of research has already been carried out for replacing
the activated charcoal with CNTs for certain ultrahigh purity
applications.
34. Nano-Electronics
● One of the most significant potential applications of SWNTs
is believed to be in the domain of nano-electronics. This is
as a result of SWNTs being highly-conductive.
● SWNT ropes are the most conductive carbon fibers known.
● Alternative configurations of a carbon nanotube can result
in the resultant material being semi-conductive like silicon.
● Conductivity in nanotubes is based on the degree of
chirality – i.e. the degree of twist and size of the diameter of
the actual nanotube - which results in a nanotube that is
actually extremely conductive (making it suitable as an
interconnect on an integrated circuit) or non-conductive
(making it suitable as the basis for semi-conductors).
35. Waste water treatment
● CNTs have a very large surface area (e.g., 500 m2 per gram
of nanotube) that gives them a high capacity to retain
pollutants such as water soluble drugs.
● A team at the University of Vienna found that at
concentrations likely to occur in the environment, the tubes
removed 13 tested Polycyclic Aromatic Hydrocarbons
(PAHs) from contaminated water. The results were recently
published in the journal Environmental Science and
Technology.
● However, there are still many health and environmental
questions to answer before such filters find their way into
municipal water treatment plants.
36. Solar cells
● Due to their strong UV/Vis-NIR absorption
characteristics, SWNTs are a potential candidates for
use in solar panels.
● Research has shown that they can provide a sizable
increase in efficiency, even at their current
unoptimized state.
37. Hydrogen storage
● By taking advantage of the capillary effects of the
small carbon nanotubes, it is possible to condense
gases in high density inside single-walled nanotubes.
This allows for gases, most notably hydrogen (H2), to
be stored at high densities without being condensed
into a liquid. Potentially, this storage method could be
used on vehicles in place of gas fuel tanks for a
hydrogen-powered car.
38. Drug delivery
● Systems being used currently for drug delivery include
dendrimers, polymers, and liposomes, but carbon nanotubes
present the opportunity to work with effective structures that
have high drug loading capacities and good cell penetration
qualities.
● These nanotubes function with a larger inner volume to be
used as the drug container, large aspect ratios for numerous
functionalization attachments, and the ability to be readily
taken up by the cell.
39. ● Because of their tube structure, carbon nanotubes can be
made with or without end caps, meaning that without end
caps the inside where the drug is held would be more
accessible.
● Right now with carbon nanotube drug delivery systems,
problems arise like the lack of solubility, clumping
occurrences, and half-life. However, these are all issues that
are currently being addressed and altered for further
advancements in the carbon nanotube field.
● The advantages of carbon nanotubes as nanovectors for drug
delivery remain where cell uptake of these structures was
demonstrated efficiently where the effects were prominent,
showing the particular nanotubes can be less harmful as
nenovehicles for drugs.
40. ● Drug encapsulation has been shown to enhance water
dispersibility, better bioavailability, and reduced
toxicity.
● Encapsulation of molecules also provides a material
storage application as well as protection and
controlled release of loaded molecules.
● All of these result in a good drug delivery basis where
further research and understanding could improve
upon numerous other advancements, like increased
water solubility, decreased toxicity, sustained half-life,
increased cell penetration and uptake, all of which are
currently novel but undeveloped ideas.
41. Biosensors
● A biosensor consists of a receptor that interacts with
the biological analyte, and this interaction is detected
by a transducer that transforms the signal (electrical,
optical, etc.) into a form that can be easily measured.
● Biosensors modified with CNTs have the advantages
of high signal-to-volume ratio, miniaturization from the
CNTs’ size being comparable to many biological
species, function at ambient temperatures, low surface
fouling and high specificity.
42. Diagnostic and imaging tools
● Tools for imaging and tracking the location and movement of
biological objects such as proteins, cells and tissues are critical
in understanding their functionalities and activities in the host
biological system.
● Such tools also provide us the ability to diagnose and possibly
cure various diseases.
● The current techniques use organic fluorophores or quantum
dots (QDs, i.e. luminescent semiconducting nanoparticles).
● However, these organic fluorophores and QDs show serious
photobleaching effect.
● They also have a limited lifetime in aqueous solutions
(approximately 1–2 weeks).
43. ● CNTs make excellent optical sensors compared to these
fluorescent probes due to photobleaching-resistance, non-
quenching, long life-time and high robustness in a
biological environment; thus, they can be exploited as non-
invasive imaging tools for both in vitro and in vivo
applications at cellular or sub-cellular levels.
44. Artificial muscles
● Carbon nano tubes have been used to develop artificial
muscles.
● The artificial muscles are yarns constructed from carbon
nanotubes and infused with paraffin wax.
● They can lift more than 100,000 times their own weight and
generate 85 times more mechanical power than the same
size natural muscle.
45. Space elevator
● A space elevator is a proposed type of space transportation
system.
● The main component would be a cable (also called a tether)
anchored to the surface and extending into space.
● The design would permit vehicles to travel along the cable
from a planetary surface, such as the Earth's, directly into
space or orbit, without the use of large rockets.
● To construct a space elevator on Earth the cable material
would need to be both stronger and lighter (have greater
specific strength) than any known material.
46. ● Carbon nanotubes (CNTs) have
been identified as possibly being
able to meet the specific
strength requirements for an
Earth space elevator.
● Other materials considered have
been boron nitride nanotubes,
and diamond nanothreads which
were first constructed in 2014.