The Production of Reduced Graphene Oxide by a Low-Cost Vacuum System for Supercapacitor Applications

2018 ◽  
Vol 930 ◽  
pp. 609-612
Author(s):  
Quezia Cardoso ◽  
Franks Martins Silva ◽  
Ligia Silverio Vieira ◽  
Julio Cesar Serafim Casini ◽  
Solange Kazume Sakata ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Low Cost ◽  
High Vacuum ◽  
Cost Effective ◽  
Practical Method ◽  
Raw Material ◽  
Vacuum System ◽  
X Ray ◽  
Pump Pressure

Graphene has attracted significant interest because of its excellent electrical properties. However, a practical method for producing graphene on a large scale is yet to be developed. Graphene oxide (GO) can be partially reduced to graphene-like sheets by removing the oxygen-containing groups and recovering the conjugated structure. GO can be produced using inexpensive graphite as the raw material via cost-effective chemical methods. High vacuum and temperature (10−7 mbar and 1100°C, respectively) conditions are well-known to enable the preparation of reduced powder at the laboratory scale. However, a large-scale high vacuum reduction system that can be routinely operated at 10−7 mbar requires considerable initial capital as well as substantial operational and maintenance costs. The current study aims at developing an inexpensive method for the large-scale reduction of graphene oxide. A stainless steel vessel was evacuated to backing-pump pressure (10−2 mbar) and used to process GO at a range of temperatures. The reduction of GO powder at low vacuum pressures was attempted and investigated by X-ray diffraction and Fourier transform infrared spectroscopy. The experimental results of processing GO powder at various temperatures (200–1000°C) at relatively low pressures are reported. The microstructures of the processed materials were investigated using scanning electron microscopy and chemical microanalyses via energy dispersive X-ray analysis.

Supercapacitor Application of Powder Prepared Using the Hydrogenation Disproportionation Desorption and Recombination (HDDR) Process in Graphene Oxide

2017 ◽  
Vol 899 ◽  
pp. 347-352 ◽  
Author(s):  
Julio Cesar Serafim Casini ◽  
Antonio Paulo Rodrigues Fernandez ◽  
Rene Ramos de Oliveira ◽  
Solange Kazumi Sakata ◽  
Rubens Nunes de Faria Jr.
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Cost Effective ◽  
Raw Material ◽  
Scale Production ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
Supercapacitor Application ◽  
Large Scale Production ◽  
Low Pressures

Graphene (G) has been attracted great interest for its excellent electrical properties. However, the large-scale production of graphene is presently unfeasible. Graphene oxide (GO) can be (partly) reduced to graphene-like sheets by removing the oxygen-containing groups with the recovery of a conjugated structure. It can be produced using inexpensive graphite as raw material by cost-effective chemical methods. Although hydrogen (mixed with argon) at high temperature (1100°C) has been employed to reduce GO powder, the hydrogenation disproportionation desorption and recombination (HDDR) process in particular was unreported for this purpose. In the present work, attempts of reducing GO powder using the HDDR process have been carried out and investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The experimental results of processing graphene oxide powder using unmixed hydrogen at moderate temperatures (about 850°C) and relatively low pressures (<2 bars) have been reported.

PRODUCTION OF STABLE DISPERSIONS OF REDUCED GRAPHENE OXIDE USING INDOLE AS A REDUCTION AGENT

NANO ◽  
2013 ◽  
Vol 08 (02) ◽  
pp. 1350017 ◽  
Author(s):  
YING HUANG ◽  
PANBO LIU ◽  
LEI WANG
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Analytical Techniques ◽  
Cost Effective ◽  
Reducing Agent ◽  
X Ray ◽  
Force Microscopy ◽  
Reduced Graphene

Stable dispersions of reduced graphene oxide (RGO) have been prepared by indole as a previously unreported reducing agent without employing any external stabilizing reagents. The obtained RGO can be individually dispersed in ethanol, N, N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO), tetrahydrofuran (THF) and isopropanol. Several analytical techniques including Atomic force microscopy, X-ray diffraction, UV-Vis spectra, Raman spectroscopy and X-ray photoelectron spectroscopy indicate that a significant fraction of the oxygen-containing functional groups are removed, yields a C/O ratio as high as 7.4. The conductivity of RGO is 21.2 S/m and the thickness of RGO increases to 1.7 nm. Furthermore, this new reducing agent is of low toxicity, which makes the reduction much safer than hydrazine and this method is cost-effective to produce single-layered RGO on a large scale.

Advances in absorbents and techniques used in wet and dry FGD: a critical review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lokesh Kumar ◽  
Susanta Kumar Jana
Keyword(s):  
Power Plants ◽  
Low Cost ◽  
Fine Particulate Matter ◽  
Packed Column ◽  
Toxic Substance ◽  
Cost Effective ◽  
Solid Wastes ◽  
Raw Material ◽  
Process Industries ◽  
Slurry Bubble Columns

Abstract Sulfur dioxide is considered as an extremely harmful and toxic substance among the air pollutants emitted from the lignite- and other high-sulfur-coal based power plants, old tires processing units, smelters, and many other process industries. Various types of absorbents and desulfurization technologies have been developed and adopted by the industries to reduce the emission rate of SO2 gas. The present paper focuses on the ongoing advances in the development of varieties of regenerative and non-regenerative absorbents viz., Ca-based, Mg-based, Fe-based, Na-based, N2-based, and others along with various FGD technology, viz., wet, dry or semi-dry processes. Additionally, different types of contactors viz., packed column, jet column, spray tower, and slurry bubble columns along with their significant operational and design features have also been discussed. In the existing or newly installed limestone-based FGD plants, an increasing trend of the utilization of newly developed technologies such as limestone forced oxidation (LSFO) and magnesium-enhanced lime (MEL) are being used at an increasing rate. However, the development of low-cost sorbents, particularly suitable solid wastes, for the abatement of SO2 emission needs to be explored sincerely. Many such wastes cause air pollution by way of entrainment of fine particulate matter (PM), groundwater contamination by its leaching, or brings damage to crops due to its spreading onto the cultivation land. One such pollutant is marble waste and in this work, this has been suggested as a suitable substitute to limestone and cost-effective sorbent for the desulfurization of flue gases. The product of this process being sellable in the market or may be used as a raw material in several industries, it can also prove to be an important route of recycling and reuse of one of the air and water-polluting solid wastes.

Development of All-Plastic Microvalve Array for Multiplexed Immunoassay

2014 ◽  
Author(s):  
Shancy Augustine ◽  
Pan Gu ◽  
Xiangjun Zheng ◽  
Toshikazu Nishida ◽  
Z. Hugh Fan
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Simultaneous Detection ◽  
Cost Effective ◽  
Negative Control ◽  
Sensitive Material ◽  
Detection Scheme ◽  
Power Battery ◽  
Multiple Analytes ◽  
Multiplexed Immunoassay

There is a need for low-cost immunoassays that measure the presence and concentration of multiple harmful agents in one device. Currently, comparable immunoassays employ a one-analyte-per-test format that is time consuming and not cost effective for the requirement of detecting multiple analytes in a single sample. For instance, if a spectrum of harmful agents, including E. coli O157, cholera toxin, and Salmonella typhimurium, should be simultaneously monitored in foods and drinking water, then a one-analyte-per-test would be inefficient. This work demonstrates a platform capable of simultaneous detection of multiple analytes in a single, low-cost, microvalve array-enabled multiplexed immunoassay. This multiplexed immunoassay platform is demonstrated in a prototype COC (cyclic olefin copolymer) device with a 2×3 array in which 6 analytes can be detected simultaneously. In order to contain and regulate the flow of reagents in the multichannel device, an array of microfluidic valves actuated by a thermally expandable material and microfabricated resistors have been developed to direct the flow to the necessary assay sites. The microvalve-based immunoassay is shown to be reliable, easy to operate, and compatible with large-scale integration. The all-plastic microvalves use paraffin wax as the thermally sensitive material which drastically reduces power consumption by latching upon closing so that pulsed power is required only to close and latch the microvalve until it is necessary to re-open the valve. The multiplexed detection scheme has been demonstrated by using three proteins, C reactive protein (CRP) and transferrin, both of which are biomarkers associated with traumatic brain injury (TBI) as well as bovine serum albumin (BSA) as the negative control. Since there are no external bulky pneumatic accessories required to operate/latch the microvalves in the device, this compact, thermally actuated and latching microvalve-enabled multiplexed immunoassay has the potential to realize a portable, low power, battery operated microfluidic device for biological assays.

Performance of rapid diagnostic tests for HCV infection in serum or plasma

2021 ◽  
Author(s):  
Stéphane Chevaliez ◽  
Françoise Roudot-Thoraval ◽  
Christophe Hézode ◽  
Jean-Michel Pawlotsky ◽  
Richard Njouom
Keyword(s):  
Hepatitis C ◽  
Diagnostic Tests ◽  
Large Scale ◽  
Low Cost ◽  
Antibody Test ◽  
Cost Effective ◽  
Rapid Diagnostic Tests ◽  
Treatment Programs ◽  
Clinical Sensitivity ◽  
Cost Treatment

Aim: HCV diagnosis will become the bottleneck in eliminating hepatitis C. Simple, accurate and cost-effective testing strategies are urgently needed to improve hepatitis C screening and diagnosis. Materials & methods: Performance of seven rapid diagnostic tests (RDT) have been assessed in a large series (n = 498) of serum or plasma specimens collected in France and in Cameroon. Results: Specificity varied from 96.1 to 100%. The clinical sensitivity, compared with immunoassays as the reference, was high for all seven RDT (97.2–100%). The Multisure HCV antibody assay and OraQuick HCV rapid antibody test reached sensitivity ≥99%. Conclusion: A number of RDT may be suitable for WHO prequalification and may be implemented in the framework of large-scale low-cost treatment programs to achieve the WHO viral hepatitis objectives by 2030.

scholarly journals Fabrication and Characterization of Humidity Sensors Based on Graphene Oxide–PEDOT:PSS Composites on a Flexible Substrate

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 148 ◽  
Author(s):  
Francisco J. Romero ◽  
Almudena Rivadeneyra ◽  
Markus Becherer ◽  
Diego P. Morales ◽  
Noel Rodríguez
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Flexible Substrate ◽  
High Sensitivity ◽  
Cost Effective ◽  
Humidity Sensors ◽  
Good Thermal Stability ◽  
Cost Effective Method ◽  
And Performance ◽  
Stability Time

In this paper, we present a simple, fast, and cost-effective method for the large-scale fabrication of high-sensitivity humidity sensors on flexible substrates. These sensors consist of a micro screen-printed capacitive structure upon which a sensitive layer is deposited. We studied two different structures and three different sensing materials by modifying the concentration of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) in a graphene oxide (GO) solution. The results show that the aggregation of the PEDOT:PSS to the GO can modify its electrical properties, boosting the performance of the capacitive sensors in terms of both resistive losses and sensitivity to relative humidity (RH) changes. Thus, in an area less than 30 mm2, the GO/PEDOT:PSS-based sensors can achieve a sensitivity much higher (1.22 nF/%RH at 1 kHz) than other similar sensors presented in the literature which, together with their good thermal stability, time response, and performance over bending, demonstrates that the manufacturing approach described in this work paves the way for the mass production of flexible humidity sensors in an inexpensive way.

scholarly journals Fabrication of Multiscale-Structure Wafer-Level Microlens Array Mold

2019 ◽  
Vol 9 (3) ◽  
pp. 487 ◽  
Author(s):  
Shuping Xie ◽  
Xinjun Wan ◽  
Xiaoxiao Wei
Keyword(s):  
Low Cost ◽  
Form Factors ◽  
Cost Effective ◽  
Microlens Array ◽  
Practical Method ◽  
Reduced Form ◽  
Wafer Level ◽  
Polycrystalline Aluminum ◽  
Microlens Arrays ◽  
Multiscale Structure

The design and manufacture of cost-effective miniaturized optics at wafer level, usingadvanced semiconductor-like techniques, enables the production of reduced form-factor cameramodules for optical devices. However, suppressing the Fresnel reflection of wafer-level microlensesis a major challenge. Moth-eye nanostructures not only satisfy the antireflection requirementof microlens arrays, but also overcome the problem of coating fracture. This novel fabricationprocess, based on a precision wafer-level microlens array mold, is designed to meet the demandfor small form factors, high resolution, and cost effectiveness. In this study, three different kinds ofaluminum material, namely 6061-T6 aluminum alloy, high-purity polycrystalline aluminum, and purenanocrystalline aluminum were used to fabricate microlens array molds with uniform nanostructures.Of these three materials, the pure nanocrystalline aluminum microlens array mold exhibited auniform nanostructure and met the optical requirements. This study lays a solid foundation for theindustrial acceptation of novel and functional multiscale-structure wafer-level microlens arrays andprovides a practical method for the low-cost manufacture of large, high-quality wafer-level molds.

scholarly journals Effect of Protocatechuic Acid on Euglena gracilis Growth and Accumulation of Metabolites

2020 ◽  
Vol 12 (21) ◽  
pp. 9158
Author(s):  
Xiaomiao Tan ◽  
Jiangyu Zhu ◽  
Minato Wakisaka
Keyword(s):  
Euglena Gracilis ◽  
Large Scale ◽  
Protocatechuic Acid ◽  
Biomass Yield ◽  
Growth Promotion ◽  
Low Cost ◽  
Cost Effective ◽  
Control Group ◽  
Biological Functions ◽  
First Time

The development of efficient, environmentally friendly, low-cost approaches used to boost the growth of microalgae is urgently required to meet the increasing demands for food supplements, cosmetics, and biofuels. In this study, the growth promotion effects of protocatechuic acid (PCA) in the freshwater microalga Euglena gracilis were confirmed for the first time. PCA is a simple phenolic compound derived from natural plants and has a range of biological functions. The highest biomass yield, 3.1-fold higher than that of the control, used at 1.3 g·L−1, was obtained at 800 mg·L−1 of PCA. The yields of the metabolites chlorophyll a, carotenoids, and paramylon in the presence of PCA at 800 mg·L−1 were 3.1, 3.3, and 1.7 times higher than those of the control group, respectively. The highest paramylon yield was achieved at a lower dosage of PCA (100 mg·L−1), which is considered to be feasible for economic paramylon production. The growth and biosynthesis of metabolites stimulated by phytochemicals such as PCA could be an efficient and cost-effective strategy to enhance the productivity of microalgae in large-scale cultivations.

scholarly journals One year later: Highlighting the challenges and opportunities in disseminating a breathing-retraining digital behaviour change intervention

2020 ◽  
Vol 6 ◽  
pp. 205520762093644
Author(s):  
Ben Ainsworth ◽  
Anne Bruton ◽  
Mike Thomas ◽  
Lucy Yardley
Keyword(s):  
Behaviour Change ◽  
Large Scale ◽  
Digital Health ◽  
Low Cost ◽  
Controlled Trial ◽  
Cost Effective ◽  
Challenges And Opportunities ◽  
Breathing Retraining ◽  
One Year ◽  
Randomised Controlled

Digital behaviour change interventions can provide effective and cost-effective treatments for a range of health conditions. However, after rigorous evaluation, there still remain challenges to disseminating and implementing evidence-based interventions that can hinder their effectiveness ‘in the real world’. We conducted a large-scale randomised controlled trial of self-guided breathing retraining, which we then disseminated freely as a digital intervention. Here we share our experience of this process after one year, highlighting the opportunities that digital health interventions can offer alongside the challenges that must be addressed in order to harness their effectiveness. Whilst such treatments can support many individuals at extremely low cost, careful dissemination strategies should be proactively planned in order to ensure such opportunities are maximised and interventions remain up to date in a fast-moving digital landscape.

scholarly journals Evaluation of an Easy-to-Install, Low-Cost Dendrometer Band for Citizen-Science Tree Research

2019 ◽  
Vol 117 (4) ◽  
pp. 317-322
Author(s):  
Michael G Just ◽  
Steven D Frank
Keyword(s):  
Citizen Science ◽  
Urban Areas ◽  
Large Scale ◽  
Low Cost ◽  
Acer Rubrum ◽  
Cost Effective ◽  
Stem Growth ◽  
Growth Monitoring ◽  
Eastern United States ◽  
Highly Correlated

AbstractTree-stem growth is an important metric for evaluating many ecological and silvicultural research questions. However, answering these questions may require monitoring growth on many individual trees that span changing environments and geographies, which can incur significant costs. Recently, citizen science has been successfully employed as a cost-effective approach to collect data for large-scale projects that also increases scientific awareness. Still, citizen-science-led tree-growth monitoring requires the use of tools that are affordable, understandable, and accurate. Here, we compare an inexpensive, easy-to-install dendrometer band to two other bands that are more expensive with more complex installations. We installed a series of three dendrometers on 31 red maples (Acer rubrum) in two urban areas in the eastern United States. We found that the stem-growth measurements reported by these dendrometers were highly correlated and, thus, validate the utility of the inexpensive band.

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