In this experimental study, the reinforcing effects of graphene oxide (GO) on portland cement paste are investigated. It is dis- covered that the introduction of 0.05% by weight GO sheets into the cement paste can increase the compressive strength and tensile strength Of the cement composite due to the reduction of the pore structure of the cement paste.The inclusion of the GO Sheets enhances the degree of hydration of the cement paste. However, the workability of the GO-cement composite becomes somewhat Reduced. The overall results indicate that GO reinforcing the engineering properties of portland cement.
The reinforcing effects of graphene oxide (GO) on portland cement paste are investigated. It is dis- covered that the introduction of 0.05% by weight GO sheets into the cement paste can increase the compressive strength and tensile strength Of the cement composite due to the reduction of the pore structure of the cement paste.The overall results indicate that GO reinforcing the engineering properties of portland cement.
RS-FLOOR CT is a lithium-based liquid designed for durable, transparent colouring of concrete surfaces.
Product description: Working principle of DRS-FLOOR CT is based on chemical interaction of
Lithium silicate with calcium hydroxide, which is available in concrete as a lime. The product of the reaction - calcium hydro-silicate - is the main bonding material in concrete. DRS-FLOOR CT paints the top layer of the concrete surface by the reaction.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
In this experimental study, the reinforcing effects of graphene oxide (GO) on portland cement paste are investigated. It is dis- covered that the introduction of 0.05% by weight GO sheets into the cement paste can increase the compressive strength and tensile strength Of the cement composite due to the reduction of the pore structure of the cement paste.The inclusion of the GO Sheets enhances the degree of hydration of the cement paste. However, the workability of the GO-cement composite becomes somewhat Reduced. The overall results indicate that GO reinforcing the engineering properties of portland cement.
The reinforcing effects of graphene oxide (GO) on portland cement paste are investigated. It is dis- covered that the introduction of 0.05% by weight GO sheets into the cement paste can increase the compressive strength and tensile strength Of the cement composite due to the reduction of the pore structure of the cement paste.The overall results indicate that GO reinforcing the engineering properties of portland cement.
RS-FLOOR CT is a lithium-based liquid designed for durable, transparent colouring of concrete surfaces.
Product description: Working principle of DRS-FLOOR CT is based on chemical interaction of
Lithium silicate with calcium hydroxide, which is available in concrete as a lime. The product of the reaction - calcium hydro-silicate - is the main bonding material in concrete. DRS-FLOOR CT paints the top layer of the concrete surface by the reaction.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
AN EXPERIMENTAL STUDY ON PROPERTIES OF TERNARY BLENDED CONCRETE USING GGBS AN...AM Publications
Ground granulated blast furnace slag (GGBS) is a by-product obtained from the blast furnaces used in the iron manufacturing industry. The disposal of the marble powder obtained from marble industry constitutes one of the environmental problems around the world. One of the possible solutions for the effective use of GGBS and marble powder is to partially replace cement in concrete. This paper presents the results of an experimental study on concrete in which the cement is partially replaced by both GGBS and marble powder. In this study, different percentages of GGBS and marble powder are used for partial replacement of cement by 30%. Tests conducted includes workability of fresh concrete (Slump test), strength of hardened concrete (Compressive strength, Split tensile strength and Flexural strength) and durability properties of concrete (Chloride resistance and Sulphate resistance).
Effect of Waste Foundry Sand on Durability Properties of ConcreteIEI GSC
Presentation on Effect of Waste Foundry Sand on Durability Properties of Concrete by Tirth Doshi guided by Dr Urmil Dave & Prof Tejas Joshi at #33NCCE 33rd National Convention of Civil Engineers at #IEIGSC
Experimental Studies on Sugar Cane Bagasse Ash based GeomaterialsDr. Amarjeet Singh
Use of conventional materials is increasing day by day due to rapid infrastructural growth which increases the cost of materials and increases the cost of construction. Hence utilization of Sugar cane bagasse ash waste materials without causing threat to environment solves the problems of disposal and also can provide economical materials. In this study glass fiber, sugarcane bagasse ash and blast furnace slag were used and cement used for binding purpose. Different mix ratio was prepared to understand the effect of addition of glass fibre on sugar cane bagasse ash based materials under compressive loading. The mix ratio was taken 0.2 to 1.0% for the research work. Blast furnace slag was added 10% to weight of sugar cane bagasse ash. The sample were tested for compressive loading for 7, 14, 28 days respectively. The density is most important parameter of materials. It was observed that the density of materials significantly influences with addition of glass fibre. The density of materials decreases with percentage of glass fiber increase. The density of materials varies between 901.1 kg/m3 to 741.10kg/m3The compressive strength also significantly affected by percentages of glass fibre. The compressive strength ranging 82 kPa to 798 kPa.The compressive strength increases up to certain mix ratio then decrease continuously. The stiffness of sugar cane bagasse ash specimens reinforced with glass fiber at cement 20% more than 15% and 10%.The stiffness also increase with the curing period. The maximum load was observed at 0.6% mix ratio. The stress strain behavior was observed to be nonlinear.
IMPACT OF MARBLE DUST ON CEMENT CONCRETE PROPERTIES SCPurohit
it is Innovative project persentation on MPACT OF MARBLE DUST ON CEMENT CONCRETE PROPERTIES (Civil Engineering) because cement which is important materail for concrete without cement concrete is useless but marble reduse the cost of cement and make it economic and reduse the cost of the project.
thank you
SCP
The influence of Rolling process on the porosity and wear behavior of Spray-f...IOSR Journals
Spray forming, also called spray casting or spray deposition, is the inert gas atomization of a liquid metal stream into variously sized droplets. These droplets are interrupted by a substrate which collects and solidifies the droplets into coherent, near fully dense perform. The present work concerns with this techniques. This technology was applied to produce Al-6%Si-20%Pb alloys. The spray droplets were deposited over a copper substrate to achieve a disc shape perform. After spray deposition samples were rolled at room temperature on two high rolling mills and total porosity and wear characteristic of spray deposits were studies. The total porosity decreases with the increase in the percentage of reduction in thickness of the samples. Thickness of the samples in both middle and peripheral region. Wear testing of spray formed and rolled Al-Si-Pb alloy were investigated on a pin on disc type wear machine. Wear rate behavior with applied load and increase in percentage of reduction in thickness of samples was observed. Wear rate increased with increasing the load and decreased with increase in percentage of reduction in thickness of the sample.
Use of Saw Dust Ash as Partial Replacement for Cement In Concreteinventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Benefits of using GGBS cement in large concrete poursDavidOFlynn
This presentation explains the benefits of using GGBS cement in reducing the risk of thermal cracking, particularly in relation to wind turbine foundations
COMPARATIVE STUDY OF COMPRESSIVE STRENGTH AND DURABILITY PROPERTIES ON GEOPOL...Journal For Research
The usage of practical advancement in structural building society has prompted the utilization of new materials with low environmental effects. One of the most commonly used construction material in the world is concrete, which is normally produced by OPC. However, the production of OPC has prompted ecological worries over the creation of CO2. Almost to create 1 ton of OPC 1 ton of CO2 is discharged to the atmosphere. With a specific end goal to diminish the utilization of OPC and CO2, the new concrete has been created, that is GEOPOLYMER CONCRETE. Latest research has demonstrated that it is conceivable to utilize fly ash or slag as a binder in concrete by activating them with alkali components through a polymerization procedure. This paper reports the point of interest of the test work that has been embraced to examine the strength and durability properties of ultra-fine slag and processed fly ash mortar mixes. At first specimens were casted for normal GGBS and fly ash in the ratio of 100:0, 75:25, 50:50, 25:75 and later for the best ratio (75:25), GGBS is replaced by ultra-fine GGBS by 7.5, 12 and 20%. Samples were compared with cured at ambient temperature and oven curing. The results showed that mix proportion of 20% replacement of ultra-fine GGBS gave the maximum strength for both oven and ambient curing (76.2 and 91.1 MPa). Even all the durability properties are within the permissible limits.
AN EXPERIMENTAL STUDY ON PROPERTIES OF TERNARY BLENDED CONCRETE USING GGBS AN...AM Publications
Ground granulated blast furnace slag (GGBS) is a by-product obtained from the blast furnaces used in the iron manufacturing industry. The disposal of the marble powder obtained from marble industry constitutes one of the environmental problems around the world. One of the possible solutions for the effective use of GGBS and marble powder is to partially replace cement in concrete. This paper presents the results of an experimental study on concrete in which the cement is partially replaced by both GGBS and marble powder. In this study, different percentages of GGBS and marble powder are used for partial replacement of cement by 30%. Tests conducted includes workability of fresh concrete (Slump test), strength of hardened concrete (Compressive strength, Split tensile strength and Flexural strength) and durability properties of concrete (Chloride resistance and Sulphate resistance).
Effect of Waste Foundry Sand on Durability Properties of ConcreteIEI GSC
Presentation on Effect of Waste Foundry Sand on Durability Properties of Concrete by Tirth Doshi guided by Dr Urmil Dave & Prof Tejas Joshi at #33NCCE 33rd National Convention of Civil Engineers at #IEIGSC
Experimental Studies on Sugar Cane Bagasse Ash based GeomaterialsDr. Amarjeet Singh
Use of conventional materials is increasing day by day due to rapid infrastructural growth which increases the cost of materials and increases the cost of construction. Hence utilization of Sugar cane bagasse ash waste materials without causing threat to environment solves the problems of disposal and also can provide economical materials. In this study glass fiber, sugarcane bagasse ash and blast furnace slag were used and cement used for binding purpose. Different mix ratio was prepared to understand the effect of addition of glass fibre on sugar cane bagasse ash based materials under compressive loading. The mix ratio was taken 0.2 to 1.0% for the research work. Blast furnace slag was added 10% to weight of sugar cane bagasse ash. The sample were tested for compressive loading for 7, 14, 28 days respectively. The density is most important parameter of materials. It was observed that the density of materials significantly influences with addition of glass fibre. The density of materials decreases with percentage of glass fiber increase. The density of materials varies between 901.1 kg/m3 to 741.10kg/m3The compressive strength also significantly affected by percentages of glass fibre. The compressive strength ranging 82 kPa to 798 kPa.The compressive strength increases up to certain mix ratio then decrease continuously. The stiffness of sugar cane bagasse ash specimens reinforced with glass fiber at cement 20% more than 15% and 10%.The stiffness also increase with the curing period. The maximum load was observed at 0.6% mix ratio. The stress strain behavior was observed to be nonlinear.
IMPACT OF MARBLE DUST ON CEMENT CONCRETE PROPERTIES SCPurohit
it is Innovative project persentation on MPACT OF MARBLE DUST ON CEMENT CONCRETE PROPERTIES (Civil Engineering) because cement which is important materail for concrete without cement concrete is useless but marble reduse the cost of cement and make it economic and reduse the cost of the project.
thank you
SCP
The influence of Rolling process on the porosity and wear behavior of Spray-f...IOSR Journals
Spray forming, also called spray casting or spray deposition, is the inert gas atomization of a liquid metal stream into variously sized droplets. These droplets are interrupted by a substrate which collects and solidifies the droplets into coherent, near fully dense perform. The present work concerns with this techniques. This technology was applied to produce Al-6%Si-20%Pb alloys. The spray droplets were deposited over a copper substrate to achieve a disc shape perform. After spray deposition samples were rolled at room temperature on two high rolling mills and total porosity and wear characteristic of spray deposits were studies. The total porosity decreases with the increase in the percentage of reduction in thickness of the samples. Thickness of the samples in both middle and peripheral region. Wear testing of spray formed and rolled Al-Si-Pb alloy were investigated on a pin on disc type wear machine. Wear rate behavior with applied load and increase in percentage of reduction in thickness of samples was observed. Wear rate increased with increasing the load and decreased with increase in percentage of reduction in thickness of the sample.
Use of Saw Dust Ash as Partial Replacement for Cement In Concreteinventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Benefits of using GGBS cement in large concrete poursDavidOFlynn
This presentation explains the benefits of using GGBS cement in reducing the risk of thermal cracking, particularly in relation to wind turbine foundations
COMPARATIVE STUDY OF COMPRESSIVE STRENGTH AND DURABILITY PROPERTIES ON GEOPOL...Journal For Research
The usage of practical advancement in structural building society has prompted the utilization of new materials with low environmental effects. One of the most commonly used construction material in the world is concrete, which is normally produced by OPC. However, the production of OPC has prompted ecological worries over the creation of CO2. Almost to create 1 ton of OPC 1 ton of CO2 is discharged to the atmosphere. With a specific end goal to diminish the utilization of OPC and CO2, the new concrete has been created, that is GEOPOLYMER CONCRETE. Latest research has demonstrated that it is conceivable to utilize fly ash or slag as a binder in concrete by activating them with alkali components through a polymerization procedure. This paper reports the point of interest of the test work that has been embraced to examine the strength and durability properties of ultra-fine slag and processed fly ash mortar mixes. At first specimens were casted for normal GGBS and fly ash in the ratio of 100:0, 75:25, 50:50, 25:75 and later for the best ratio (75:25), GGBS is replaced by ultra-fine GGBS by 7.5, 12 and 20%. Samples were compared with cured at ambient temperature and oven curing. The results showed that mix proportion of 20% replacement of ultra-fine GGBS gave the maximum strength for both oven and ambient curing (76.2 and 91.1 MPa). Even all the durability properties are within the permissible limits.
FSP LED PSU :
We provide comprehensive and flexible LED Driver solutions that fit your needs in lighting applications. We emphasize on robust design, highest reliability and excellent dimming.
Grinding graphene characteristics after physical processjournal ijrtem
ABSTRACT : Graphene features higher thermal conductivity than copper. However, despite its superior property, the research on its applicable technology was limited since the van der Waals’ forces between graphene. As a solution to such problem, research on making graphene distributed evenly in solvent is being actively conducted via physical and chemical method. Because the chemical method is likely to have harmful effect on the environment, we used the environmental-friendly process that does not consume toxic chemicals, and suitable for application. In this study, ball milling process controllable a range of experiment conditions more easily and conveniently than other physical methods was conducted so as to disperse graphene evenly in solvent and improve the thermal conductivity. Therefore, the effect of milling process was confirmed in TEM image and Raman ratio, and the shearing force makes the edge of graphene piece defective. When graphene is evenly dispersed, the wide specific surface area absorbs a great deal of light, improving absorbance. We confirmed the absorbance of pristine graphene was showed below milling graphene and considerable thermal conductivity increase compared to pristine graphene.
Keywords: Ball milling, Graphene, Nano-fluid, Physical process, Thermal conductivity
Modeling of Dirac voltage for highly p-doped graphene field-effect transistor...journalBEEI
In this paper, the modeling approach of Dirac voltage extraction of highly p-doped graphene field-effect transistor (GFET) measured at atmospheric pressure is presented. The difference of measurement results between atmospheric and vacuum pressures was analyzed. This work was started with actual wafer-scale fabrication of GFET with the purposes of getting functional device and good contact of metal/graphene interface. The output and transfer characteristic curves were measured accordingly to support on GFET functionality and suitability of presented wafer fabrication flow. The Dirac voltage was derived based on the measured output characteristic curve using ambipolar virtual source model parameter extraction methodology. The circuit-level simulation using frequency doubler circuit shows the importance of accurate Dirac voltage value to the device practicality towards design integration.
Progress in Synthesis of Graphene using CVD, Its Characterization and Challen...paperpublications3
Abstract: Diamond and Graphite both are natural allotropes of carbon. Graphene is a substance composed of sp2 hybridized carbon atoms that are similar to graphite and arranged in a regular hexagonal pattern. Graphene has astounding physical properties such as high electronic conductivity, excellent mechanical strength and thermal stability. It is capable to maintain its strength up to 3,600°C. It is transparent, high super hydrophobicity at nanometer scale , 100 times stronger than steel with high current density. These unique properties make graphene an interesting candidate for a number of applications currently under development, as for instance Li-ion batteries, transparent touch screens, light weight aircrafts or transistors.
Amongst the synthesis techniques, chemical vapor deposition has proved promising result for advance devices and for numerous applications where high-quality graphene films, High purity, fined grained and low structural defects film is required. CVD process is normally conducted below the atmospheric pressure and relatively lower temperatures , less than 1000°C. Pressure of LPCVD is 10-1000 Pascals.
Keywords: CVD, Graphene, Graphite, Graphene sheets..
Title: Progress in Synthesis of Graphene using CVD, Its Characterization and Challenges: A Review
Author: Sakshi Rana, Harminder Singh
International Journal of Recent Research in Electrical and Electronics Engineering (IJRREEE)
ISSN 2349-7815
Paper Publications
Graphene: the world's first 2D material. Since graphene's isolation in 2004, it has captured the attention of scientists, researchers, and industry worldwide.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
SAP Sapphire 2024 - ASUG301 building better apps with SAP Fiori.pdfPeter Spielvogel
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• How a better user experience drives measurable business benefits
• How to get started with SAP Fiori today
• How SAP Fiori elements accelerates application development
• How SAP Build Code includes SAP Fiori tools and other generative artificial intelligence capabilities
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Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Le nuove frontiere dell'AI nell'RPA con UiPath Autopilot™UiPathCommunity
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📕 Vedremo insieme alcuni esempi dell'utilizzo di Autopilot in diversi tool della Suite UiPath:
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Clipboard AI
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How can you help your company evolve, adapt, and succeed using Artificial Intelligence and the Metaverse to stay ahead of the competition? What are the potential issues, complications, and benefits that these technologies could bring to us and our organizations? In this session, Jen Stirrup will explain how to start thinking about these technologies as an organisation.
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The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
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Bob Boule
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My slides at Nordic Testing Days 6.6.2024
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GenAISummit 2024 May 28 Sri Ambati Keynote: AGI Belongs to The Community in O...
Graphene and three roll mill
1. Continuous mechanical exfoliation of graphene sheets via three-roll mill†
Jinfeng Chen, Miao Duan and Guohua Chen*
Received 11th June 2012, Accepted 3rd August 2012
DOI: 10.1039/c2jm33740a
In this work, single and few-layer graphene sheets have been
successfully peeled from natural graphite through continuous
mechanical exfoliation by a three-roll mill machine with a polymer
adhesive. The inspiration takes root in the ‘‘Scotch tape’’ method.
Characterizations show that the thickness of the resultant graphene
sheets is 1.13–1.41 nm. The presented scalable process can be
effective for the high-yield and low-cost production of graphene
sheets or in situ fabrication of polymer/graphene nanocomposites.
Graphene, consisting of a single atomic layer of graphite, is an
exciting material for future advanced applications. Because of the
excellent electrical, optical, mechanical and thermal properties,1
it has
emerged as a rapidly rising star in diverse fields such as super-
capacitors,2
semiconductor devices, support for catalysts, conductive
transparent electrodes, biosensors3
and batteries, among others.4
To date, there have been several widely used techniques to produce
‘‘pristine’’ graphene: micromechanical exfoliation,5
epitaxial growth
on SiC,6
chemical vapour deposition (CVD)7
and chemical exfolia-
tion of graphite oxide (GO),8
etc. Of these reported approaches, the
micromechanical cleavage of graphite using the ‘‘Scotch tape’’
method is the original, which was the first used to mechanically split
graphite into individual atomic planes and provided the best
graphene for the study of its fundamental properties. However, this
method is unlikely to be suitable for large scale production. Other-
wise, large-area single-layer 30 inch graphene films have been grown
by CVD, which is one of the best techniques to grow graphene film
on various metals by using gaseous hydrocarbon sources. Unsatis-
factorily, this is an extremely careful fabrication process, considered
to be too tedious and too expensive for mass production.9
The
chemical exfoliation of graphite oxide can be easily dispersed in
aqueous solution in favour of the materials processing and funda-
mental characterization, but in fact it results in considerable disrup-
tion of the electronic structure of graphene.10
Thus, a simple,
economic and facile approach to produce significant quantities of
defect free, un-oxidised graphene to facilitate its applications and
studies is urgently required.
This work is inspired by the ‘‘Scotch tape’’ method and presents a
novel and simple method for the low-cost and large scale production
of monolayer and few-layer graphene sheets via continuous direct
exfoliation of natural graphite by a three-roll mill, which is a common
machine in the rubber industry.
Firstly, 2.0 g poly vinyl chloride (PVC) was dispersed in 50 ml
dioctyl phthalate (DOP) at 250
C for 30 min by a magnetic stirrer to
prepare an adhesive. 1.0 g of natural graphite with an average size of
500 mm was pre-dried at 100
C for 24 h and then the adhesive was
placed between the feed and the centre rolls of the three-roll mill.
Once the rolls started moving, the prepared natural graphite was
spread gradually on the adhesive to achieve maximum contact with
the rolls, followed by the uniform dispersion and exfoliation of the
graphite in the adhesive. Exfoliation was carried out at room
temperature for 12 h. After that, the material from the mill was
collected and steeped in alcohol to remove the DOP, followed by the
burning out of the PVC resin in the muffle at 500
C for 3 h in order
to extract the pure graphene product. A schematic of the preparation
process is illustrated in Fig. 1, and a video of the exfoliation process is
included in the ESI.†
In this work, the three-roll mill consisted of three adjacent cylin-
drical rolls (80 mm in diameter), which rotated at the same velocity.
The first and the third rolls, known as the feed and apron rolls, rotate
in the same direction while the centre roll rotates in the opposite
direction (Fig. 1). The gap and speed settings on the mill can be
controlled. With the help of force, the graphite runs in an inverted S
curve from the feed roll to the apron roll, then turns back towards the
feed roll. In this way, the graphite can be continuously exfoliated,
Fig. 1 Schematic illustration of the approach used to exfoliate natural
graphite by a three-roll mill.
Department of Polymer Science Engineering, Huaqiao University,
Xiamen, 361021, China. E-mail: hdcgh@hqu.edu.cn; Fax: +86-592-
6166296; Tel: +86-592-6166296
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c2jm33740a
This journal is ª The Royal Society of Chemistry 2012 J. Mater. Chem., 2012, 22, 19625–19628 | 19625
Dynamic Article LinksCJournal of
Materials Chemistry
Cite this: J. Mater. Chem., 2012, 22, 19625
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2. which is the crucial difference between this method and the ‘‘Scotch
tape’’ method (Fig. S1†). Fig. S2† shows SEM images of the gra-
phene produced in the three-roll mill steps. As the edge defects come
into existence during the three-roll mill exfoliation, the conductivity
of the graphene product after 12 h exfoliation is 7.5 Â 103
S mÀ1
,
while that of the natural graphite is 2.5 Â 104
S mÀ1
. The conduc-
tivity is higher compared to graphene obtained from the chemical
exfoliation of graphite oxide due to the structure of the graphene have
been retained well.
The prepared graphene sheets were characterized by high-resolu-
tion transmission electron microscopy (HRTEM, JEM-2010) and
selected-area electron diffraction. The HRTEM specimens were
prepared by loading the microtomed epoxy composite slices of the as-
obtained graphene onto standard TEM grids.11
Atomic force
microscopy (AFM, NanoScope IIIa) was used to determine accu-
rately the thicknesses of the graphene sheets and a high resolution
dispersive Raman microscope (LabRAM Aramis) with an excitation
laser witha wavelength of 532 nm was carried out to further char-
acterize the graphene structure.
The HRTEM image in Fig. 2a shows that the sizes of the graphene
sheets are homogeneous and have lateral dimensions on the submi-
cron scale. The cross-sections of the obtained graphene sheets are
shown in Fig. 2b and the number of layers can be visualized directly:
a single-layer and a three-layer sheet of graphene are marked in
Fig. 2b. It confirms that the graphene product is likely to be in forms
of single- or few-layer sheets. As one dark line dominates a single
atomic carbon layer, the thickness is about $0.5 nm. The typical
selective electron area diffraction (SAED) pattern (Fig. 2c) demon-
strates that the graphene sheets have good crystallinity, in which spots
(0–110) and (À1010) are more intense than spots (1–210) and
(À2110), reconfirming the single-layer feature of the graphene.12
Fig. 3a shows the typical tapping-mode AFM image of graphene
deposited on a mica substrate. In Fig. 3b the cross-sectional analysis
shows that the graphene sheet has a thickness of 1.13–1.41 nm, and it
canbeobservedthatthegraphenesheethasasizeof$2.7Â 5.0mm.At
a high resolution, the apparent thickness obtained by AFM may be a
layerofabsorbedwaterorsolventbetweenthegraphenesheetsandthe
substrate for the chemical and van der Waals contrast. Furthermore,
an instrumental offset of $ ca. 0.5 nm (caused by different interaction
forces) always exists, which is even larger than the thickness of a single
layer of graphene, so graphene films of the theoretical thickness (ca.
0.34nm)arerarelyobservedbyAFM,13
andthicknessesofca.1nmare
reported normally.14
Thus the graphene sheets found can be estimated
assingle-layerordouble-layergraphenesheets.Thisresultisconsistent
with the above HRTEM observation. It was proved that with the help
of mechanical force the polymer adhesive is sufficient to overcome the
van der Waals forces between the graphene sheets, which successfully
amplified the ‘‘Scotch tape’’ method.
To further investigate the graphene product structure, Raman
spectroscopy of the natural graphite and graphene product were
carried out. Fig. 4 shows the Raman spectra of natural graphite
(green line) and graphene sheets (red line). The two most intense
features of the graphene sheets and the graphite are the G peak at
$1580 cmÀ1
and 2D peak at $2700 cmÀ1
. A single and symmetric
Lorentzian 2D peak (2690 cmÀ1
) is generated in the red line, indi-
cated that the graphene product is probably a single-layer graphene
sheet. In addition, the 2D position is 29–30 cmÀ1
lower than that of
natural graphite. This down-shift and the sharp peak is similar to the
thin graphene data reported previously.15
What is more, the D/G
peak intensity ratio (ID/IG) for the graphene product is 0.06, which is
lower than the value for the chemical exfoliation of graphite oxide,
indicating the perfect structure of the resultant graphene.8
Interest-
ingly, the G peak is also gradually down-shifted towards that of the
natural graphite. Similar phenomena have been reported, in which,
because of the chemical doping effects,16
the frequency shift of the G
peak is a more significant modification in thinner graphene sheets.17
However, the reason attributed to this phenomenon is not clear.
Fig. 2 (a) and (b) High-resolution TEM imaging of graphene products
embedded in epoxy resin slice. (c) The SAED pattern corresponding to
the inset TEM image of the graphene sheets thin edge and the intensity
scan along the solid line.
19626 | J. Mater. Chem., 2012, 22, 19625–19628 This journal is ª The Royal Society of Chemistry 2012
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3. Evidently, with the help of mechanical force, the polymer adhesive
is sufficient to peel the natural graphite into single and few-layer
graphene sheets. As many flakes were observed in the HRTEM, we
count the number of graphene layers per flake for a number of flakes
from Fig. 2b and the additional image shown in Fig. S3† to
approximately calculate that the ratio of the single and few-layer
(#10) graphene sheets is around 90%, with the single-layer sheets
constituting at least 50%.14
However, based on the current results, it is
reasonable to deduce that an eventual increase of the yield of single-
layer graphene sheets can be accomplished by optimizing the exfoli-
ation conditions such as the rolling time, the speed of rolling, the
properties of the polymer adhesive and so on.
In conclusion, mechanical delamination by a three-roll mill
machine with a polymer adhesive offers the possibility of the large-
scale production of graphene monolayers or ultrathin graphene
layers starting from natural graphite. As a very common industrial
technique in the rubber industry, the method can be applicable for the
industrial production of graphene product. Obviously, the process
could also be applicable for the preparation of polymer/graphene
composites, as long as one is careful to choose the polymer and
exfoliation parameters properly.
Further work will be focused on the properties of the polymer
adhesive and the exfoliation conditions such as the rolling time,
temperature, speed of rolling, etc.
Acknowledgements
This work was funded by Natural Science Foundation of China
(20574025, 50373015) and Science Foundation of Xiamen
(3502Z20103032).
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