Improved efficiency of liquid-phase shear exfoliation of expanded graphite with bifunctional additives of mica plates

Author(s):  
Bin Liang ◽  
Kangwei Liu ◽  
Peng Liu ◽  
Guangyao Zhao ◽  
Weisheng Pan ◽  
...  

Liquid-phase shear exfoliation (LPSE) has been a potential way of large-scale production of good-quality graphene. How to obtain few-layer (<10) graphene with large lateral sizes and high yields remains a...

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5368
Author(s):  
Yunxiu Ren ◽  
Chao Xu ◽  
Tieying Wang ◽  
Ziqian Tian ◽  
Zhirong Liao

The fabrication of form-stable phase change materials (FS-PCMs) usually involves four manufacturing processes: mixing, immersion, stabilization, and sintering. In each process, the operation parameters could affect the performance of the fabricated PCM composite. To gain an efficient and low-cost method for large-scale production of the molten salts/expanded graphite (EG) composite FS-PCMs, the effects of different operating parameters were investigated, including the stirring speed, evaporation temperature, melt-impregnation, cold-pressing pressure, and sintering temperature on the densification, microstructure, and thermophysical properties of the composite FS-PCMs. It was found that the microstructure, the morphology and durability, and the thermophysical properties such as thermal conductivity and specific heat enthalpy depended highly on the operating parameters. The following optimal operating parameters of the Ca(NO3)2–NaNO3/EG composite FS-PCMs are suggested: the stirring speed of 20 rpm, the evaporation temperature of 98 °C, the melt-impregnation temperature of 280 °C, the cold-pressing pressure of 8 MPa, and the sintering temperature of 300 °C. The results of the present work can provide valuable insights for the large-scale production of the composite FS-PCMs.


Amylase ◽  
2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Gregory L. Côté ◽  
Christopher A. Dunlap ◽  
Karl E. Vermillion ◽  
Christopher D. Skory

AbstractCertain lactic acid bacteria produce glycosyltransferases known as glucansucrases, which synthesize α-D-glucans via glucosyl transfer from sucrose. We recently reported on the formation of the unusual trisaccharide isomelezitose in low yields by a variety of glucansucrases. Isomelezitose is a rare non-reducing trisaccharide, with the structure α-d-glucopyranosyl- (1→6)-β-d-fructofuranosyl-(2↔1)-α-d-glucopyranoside. In this work, we describe the synthesis of isomelezitose in high yields by variants of glucansucrases engineered to contain a single point mutation at a key leucine residue involved in acceptor substrate binding. Some variants produce isomelezitose in yields up to 57%. This method is amenable to large-scale production of isomelezitose for food, industrial and biomedical applications.


2013 ◽  
Vol 24 (47) ◽  
pp. 475602 ◽  
Author(s):  
Yunwei Wang ◽  
Xili Tong ◽  
Xiaoning Guo ◽  
Yingyong Wang ◽  
Guoqiang Jin ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3253
Author(s):  
Freskida Goni ◽  
Angela Chemelli ◽  
Frank Uhlig

Liquid-phase exfoliation (LPE) is a widely used and promising method for the production of 2D nanomaterials because it can be scaled up relatively easily. Nevertheless, the yields achieved by this process are still low, ranging between 2% and 5%, which makes the large-scale production of these materials difficult. In this report, we investigate the cause of these low yields by examining the sonication-assisted LPE of graphene, boron nitride nanosheets (BNNSs), and molybdenum disulfide nanosheets (MoS2 NS). Our results show that the low yields are caused by an equilibrium that is formed between the exfoliated nanosheets and the flocculated ones during the sonication process. This study provides an understanding of this behaviour, which prevents further exfoliation of nanosheets. By avoiding this equilibrium, we were able to increase the total yields of graphene, BNNSs, and MoS2 NS up to 14%, 44%, and 29%, respectively. Here, we demonstrate a modified LPE process that leads to the high-yield production of 2D nanomaterials.


1993 ◽  
Vol 32 (1) ◽  
pp. 129-131
Author(s):  
Naureen Talha

The literature on female labour in Third World countries has become quite extensive. India, being comparatively more advanced industrially, and in view of its size and population, presents a pictures of multiplicity of problems which face the female labour market. However, the author has also included Mexico in this analytical study. It is interesting to see the characteristics of developing industrialisation in two different societies: the Indian society, which is conservative, and the Mexican society, which is progressive. In the first chapter of the book, the author explains that he is not concerned with the process of industrialisation and female labour employed at different levels of work, but that he is interested in forms of production and women's employment in large-scale production, petty commodity production, marginal small production, and self-employment in the informal sector. It is only by analysis of these forms that the picture of females having a lower status is understood in its social and political setting.


2018 ◽  
Vol 15 (4) ◽  
pp. 572-575 ◽  
Author(s):  
Ponnusamy Kannan ◽  
Samuel I.D. Presley ◽  
Pallikondaperumal Shanmugasundaram ◽  
Nagapillai Prakash ◽  
Deivanayagam Easwaramoorthy

Aim and Objective: Itopride is a prokinetic agent used for treating conditions like non-ulcer dyspepsia. Itopride is administered as its hydrochloride salt. Trimethobenzamide is used for treating nausea and vomiting and administered as its hydrochloride salt. The aim is to develop a novel and environmental friendly method for large-scale production of itopride and trimethobenzamide. Materials and Methods: Itopride and trimethobenzamide can be prepared from a common intermediate 4- (dimethylaminoethoxy) benzyl amine. The intermediate is prepared from one pot synthesis using Phyrdroxybenzaldehye and zinc dust and further reaction of the intermediate with substituted methoxy benzoic acid along with boric acid and PEG gives itopride and trimethobenzamide. Results: The intermediate 4-(dimethylaminoethoxy) benzylamine is prepared by treating p-hydroxybenzaldehyde and 2-dimethylaminoethyl chloride. The aldehyde formed is treated with hydroxylamine hydrochloride. The intermediate is confirmed by NMR and the purity is analysed by HPLC. Conclusion: Both itopride and trimethobenzamide were successfully synthesized by this method. The developed method is environmental friendly, economical for large-scale production with good yield and purity.


Marine Drugs ◽  
2021 ◽  
Vol 19 (5) ◽  
pp. 241
Author(s):  
Shaden A. M. Khalifa ◽  
Eslam S. Shedid ◽  
Essa M. Saied ◽  
Amir Reza Jassbi ◽  
Fatemeh H. Jamebozorgi ◽  
...  

Cyanobacteria are photosynthetic prokaryotic organisms which represent a significant source of novel, bioactive, secondary metabolites, and they are also considered an abundant source of bioactive compounds/drugs, such as dolastatin, cryptophycin 1, curacin toyocamycin, phytoalexin, cyanovirin-N and phycocyanin. Some of these compounds have displayed promising results in successful Phase I, II, III and IV clinical trials. Additionally, the cyanobacterial compounds applied to medical research have demonstrated an exciting future with great potential to be developed into new medicines. Most of these compounds have exhibited strong pharmacological activities, including neurotoxicity, cytotoxicity and antiviral activity against HCMV, HSV-1, HHV-6 and HIV-1, so these metabolites could be promising candidates for COVID-19 treatment. Therefore, the effective large-scale production of natural marine products through synthesis is important for resolving the existing issues associated with chemical isolation, including small yields, and may be necessary to better investigate their biological activities. Herein, we highlight the total synthesized and stereochemical determinations of the cyanobacterial bioactive compounds. Furthermore, this review primarily focuses on the biotechnological applications of cyanobacteria, including applications as cosmetics, food supplements, and the nanobiotechnological applications of cyanobacterial bioactive compounds in potential medicinal applications for various human diseases are discussed.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.


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