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Published By Bentham Science Publishers Ltd.

2666-1454

2021 ◽  
Vol 15 ◽  
Author(s):  
Ranjan K Sahu

Background: Fe 3sXPS spectrumexhibits doublet peak instead of predicted singlet peak based on spin-orbit coupling theory. This anomalous behavior is considered to be magnetic origin. However, the effect of residual magnetic moment to the features of Fe3s doublet peakis not understood fully. Objective: This study aims to verify the effect of residual magnetic moment on the spectral features of Fe3s XPS spectrum of magnetic material. Method: As a case study, we have carried out a high temperature XPS study of the Fe 3s spectrum of magnetic domain aligned (MDA) sample with composition composed of SrFe10.8Al1.2O19. In addition, the XPS data have been compared with the data acquired at different temperatures of magnetic domain non-aligned (MDNA) sample. Results: The results show that the majority peak intensity and minority peak width of Fe 3s spectrum of MDA are smaller than those of the MDNA sample, and they increase systematically with increasing temperature. However, it is noted that the features of Fe3s spectrum of both MDA and MDNA samples are completely overlapped near and above the Curie temperature, Tc ~ 670K. Conclusion: The analysis of XPS data suggests that the residual magnetic moment influences the spectral features of Fe3s spectrum. These results provide evidences that it is important to consider the contribution of residual magnetic moment while deriving information from Fe 3s XPS spectrum of MDA sample.


2021 ◽  
Vol 15 ◽  
Author(s):  
Agnivesh Kumar Sinha ◽  
Kasi Raja Rao ◽  
Vinay Kumar Soni ◽  
Rituraj Chandrakar ◽  
Hemant Kumar Sharma ◽  
...  

Presently, scientists and researchers are in an endless quest to develop green, recyclable, and eco-friendly materials. Natural fibre reinforced polymer composites became popular among materialists due to their lightweight, high strength-to-weight ratio, and biodegradability. However, all-natural fibre reinforced polymer composites are not biodegradable. Polymer matrices like poly-lactic acid (PLA) and poly-butylene succinate (PBS) are biodegradable, whereas epoxy, polypropylene, and polystyrene are non-biodegradable polymer matrices. Besides biodegradability, PLA has been known for its excellent physical and mechanical properties. This review emphasises the mechanical properties (tensile, flexural, and impact strengths) of natural fibrereinforced PLA composites. Factors affecting the mechanical properties of PLA composites are also discussed. It also unveils research gaps from the previous literature, which shows that limited studies are reported based on modeling and prediction of mechanical properties of hybrid PLA composites reinforcing natural fibres like abaca, aloe vera, and bamboo fibres.


2021 ◽  
Vol 15 ◽  
Author(s):  
Adriana Estokova ◽  
Martina Kovalcikova

Background: Cementitious composites, which are subject to increasing demands, are often exposed to various external attacks, such as aggressive groundwater and surface water, chemicals in the soil, gas penetration, or phenomena related to water freezing and melting. One of the most common reasons for the deterioration of cement composites is the corrosion process. Corrosion results in irreversible damage that occurs during the chemical reaction of the material with the components of the environment. Methods: The paper deals with experimental study of chemical sulphate corrosion of cement composites prepared from three types of cement: ordinary Portland cement; sulphate-resistant cement; and special hybrid cement, and industrial by-products and wastes: silica fume, zeolite and a special mineral admixture based on blast furnace granular slag as cement partial substitutes. Samples of cement composites were subjected to corrosion experiments in a sulphate environment, which took place in the laboratory under model conditions for 180 resp. 270 days. Results: The deterioration parameters: changes in the weight and thickness of the samples, surface and mineralogical changes, leachability of the basic components of the cement matrix as well as changes in the liquid phase proved the degradation process due to chemical sulphate corrosion, model solutions of H2SO4 with pH 3 and 4, and solution of MgSO4 with c (SO4 2 - ) = 3 and 10 g /L. Conclusion: By comparing the leachability of the alkali components from cement composites, it can be concluded that for the most aggressive model solution (H2SO4 with pH 3), both slagcontaining formulations are the most stable in terms of the total ratio of leached calcium and silicon. This finding is also supported by the results of water absorbency tests, which confirmed that despite the increase in absorbency after chemical corrosion, cement composites with slag content reach the lowest values.


2021 ◽  
Vol 15 ◽  
Author(s):  
Patience Danquah Monnie ◽  
Rachel Amanfu ◽  
Modesta Efua Gavor

Background: Formaldehyde is a chemical used in several textile production processes, such as hardening of fibers and antimold finishing. However, it has varying effects on humans, such as irritation of the eyes, nose, throat, wheezing, chest pains and bronchitis. In the midst of COVID-19, individuals are using various fabrics for face mask production, which may be containing levels of formaldehyde that can negatively affect their health. Methods: This study investigated formaldehyde levels in fabrics on the Ghanaian market to determine compliance to standards set by the Ghana Standards Authority (GSA) with the aid of experimental procedures. Thirty-two (32) different brands of fabrics were selected for the investigation. Formaldehyde levels were determined using a spectrophotometer (DR6000). Data were analyzed using the Statistical Product and Service Solutions (SPSS) for Windows version 22. The mean performance attributes and the formaldehyde levels of the sampled fabrics were determined before and after washing. Inferential statistics (Analysis of Variance and Paired Samples t-test) at 0.05 alpha levels were used to determine significant differences between and among the groups involved. Results: The fabric samples tested positive for formaldehyde before and after washing, with some exceeding the standard limits set by the GSA before washing. Significant differences existed between and among the samples with regard to formaldehyde levels as well as weight and weave types of the samples and formaldehyde levels. Conclusion: Washing significantly reduced the formaldehyde levels in the fabrics. It is recommended that Ghana standards authority takes a further look at the fabrics on the Ghanaian market to ensure manufacturers comply with set standards and consumers are also advised to wash their clothes at least once before use to reduce the level of impact formaldehyde resin may have on them.


2021 ◽  
Vol 14 ◽  
Author(s):  
C.H. Yu ◽  
Z.Y. Xue ◽  
Y.J. Mao ◽  
J. F. Huang ◽  
F.H. Tao ◽  
...  

Background: Gentian violet dye released from industries into the environment has caused serious water pollution and is a significant environment pollutant to human beings owing to the toxicity. It is urgent to decrease the environmental pollution by removing gentian violet in the wastewater. Objective: The aim is to synthesize hexahydroxy strontium stannate/tin dioxide nanocomposites by a simple hydrothermal method without surfactants and research the photocatalytic performance for gentian violet degradation. Methods: Hexahydroxy strontium stannate/tin dioxide nanocomposites have been obtained via the hydrothermal method. The structure, size, morphology and photocatalytic performance were characterized by X-ray diffraction, electron microscopy, solid ultraviolet-visible diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. Results : The nanocomposites possess oven-shaped morphology with the size of less than 100 nm and are composed of hexagonal SrSn(OH)6 and tetragonal SnO2 phases. The band gap of the nanocomposites is 3.52 eV. 10 mg hexahydroxy strontium stannate/tin dioxide nanocomposites have the ability to completely degrade 10 mL gentian violet solution with the concentration of 10 mgL-1 under 6 h ultraviolet-visible light irradiation. Hydroxyl radical, hole and superoxide radical are main species for the gentian violet photocatalytic degradation using the nanocomposites. Conclusion: The hexahydroxy strontium stannate/tin dioxide nanocomposites show good photocatalytic performance for the GV degradation. The photocatalytic performance for gentian violet degradation using the hexahydroxy strontium stannate/tin dioxide nanocomposites depends on the irradiation time and content of the nanocomposites.


2021 ◽  
Vol 14 ◽  
Author(s):  
Reda E. Abo El-Fadl ◽  
Mahmoud M. El-Saber ◽  
Manal E.A. Ahmed ◽  
Tamer M. Abd Elaziem ◽  
Ahmed A. El-Sayed

Background: Green synthesis of nanoparticles has provided a cost-effective, environmentally friendly method, as well as raised safe strategies for the synthesis of nanomaterials. In this study, we investigated the synthesis of selenium nanoparticles from the leaf aqueous extract of Moringa oleifera (MO-SeNPs) and studied the effect of MO-SeNPs and Moringa extract with various concentrations on growth, active constituents, and antioxidant activity (scavenging DPPH) of Populus alba callus. MS medium supplemented with 2, 4-D at 2 mg/l + 0.5 mg/l BA took the maximum callus induction percentage (100%), increasing the callus fresh weight, dry weight, and degree of callus formation compared with 2.0 mg/l 2,4-D + 0.5 mg/l Kin. Methods: The highest values of callus fresh and dry weight were recorded on MS containing 20% MO-SeNPs. Regarding the active constituents, the GC-MS chromatogram revealed the presence of 23 major compounds identified in the chloroform extract. The phytoconstituents with maximum peak area in callus extract are Tetradecane, Hexadecen-1-ol,trans-9-, 5-Octadecene, (Benzene, 1-pentyloctyl), (Benzene, 1-butylnonyl), Cycloeicosane, and 10-Heneicosene in all treatments. Moringa extract and MO-SeNPs stimulate the increase of compounds in the callus compared to control. In this regard, MO-SeNPs 5% led to a higher increase in the area percent of active substances compared to the treatment of Moringa extract and control. Results: Concerning the antioxidant activity, the results indicated that Moringa extract and MO-SeNPs had a positive effect on scavenging DPPH compared with the control. Conclusion : The highest percentages of scavenging DPPH were recorded when Populus alba L. callus was treated with MO-SeNPs 20%, 10%, and Moringa extract 20%, percentages reached 84.65, 75.35, and 71.94 %, respectively.


2021 ◽  
Vol 14 ◽  
Author(s):  
Hui-Hsin Huang

Background: The issue of material demands prediction has been researched in industrial study and materials/ manufacturing technology many years ago. The previous researches based on stochastic model to discuss the quantities prediction of material demand. Some of them focus on multi-suppliers with characteristic function. Some use the information of past ordering quantities and ordering recency time. In these previous models, there is less study to discuss the impact of cost on material demand forecasting. Thus, this paper considers the productivities concept to make cost balance when forecasting material demand. The different probability distributions are demonstrated to portray the input (material demand) and output(cost). Methods: A case study with its empirical data is released to derive the probability function of cost and estimate the parameters of the proposed model. Results: The proposed model can extend to different distributions depending on different kind of cost or different type of industries and is more widely application. Conclusion: To consider manufacture's productivity, this model can help manager to control their cost and make a balance when ordering their materials. The model development of cost release a general function which makes it possible to extend different distributions depending on different kind of cost or different type of industries.


2021 ◽  
Vol 14 ◽  
Author(s):  
Raghav Mishra ◽  
Radhika Agarwal

Background: Localized drug delivery to the respiratory system has become an increasingly successful and essential treatment strategy for several pulmonary diseases, including asthma, chronic abstractive disease, pneumonia, bronchitis, and cystic fibrosis. The rising incidence of respiratory diseases is a significant factor driving the worldwide market for respiratory inhaler devices. Objective: The objective of this article is to present various aspects of pharmaceutical aerosols, including their types, components, fundamentals, in-process and finished product quality control tests based on pharmacopeial standards and specifications, and commercial utility considering the pharmaceutical aerosol dosage forms that have been patented from 2000 to 2020, along with a list of marketed pharmaceutical products. Method: Aerosol, collectively referred to as a pressurized device, operates by triggering an appropriate valve system with a continuous or metered dosage of tiny mist spray. It is used not only in the treatment of asthma and chronic obstructive pulmonary disease but also in the treatment of cancer, diabetes, migraine, angina pectoris, acute lung injury, bone disorders, tuberculosis, and many more. A multitude of different variables, including types and properties of propellants, active substances, containers, valves, actuators, spray patterns, valve crimping efficiency, and particle size of the aerosols, influence the therapeutic effectiveness of pharmaceutical aerosols. Conclusion: Based on the current findings, distinct characteristics such as the elimination of firstpass metabolism, quick drug absorption, ease of therapy termination, as well as a larger surface area have attributed to the success of pharmaceutical aerosols.


2021 ◽  
Vol 14 ◽  
Author(s):  
A. Guillermo Bracamonte

: Graphene as Organic material showed special attention due to their electronic and conductive properties. Moreover, its highly conjugated chemical structures and relative easy modification permitted varied design and control of targeted properties and applications. In addition, this Nanomaterial accompanied with pseudo Electromagnetic fields permitted photonics, electronics and Quantum interactions with their surrounding that generated new materials properties. In this context, this short Review, intends to discuss many of these studies related with new materials based on graphene for light and electronic interactions, conductions, and new modes of non-classical light generation. It should be highlighted that these new materials and metamaterials are currently in progress. For this reason it was showed and discussed some representative examples from Fundamental Research with Potential Applications as well as for their incorporations to real Advanced devices and miniaturized instrumentation. In this way, it was proposed this Special issue entitled “Design and synthesis of Hybrids Graphene based Metamaterials”, in order to open and share the knowledge of the Current State of the Art in this Multidisciplinary field.


2021 ◽  
Vol 14 ◽  
Author(s):  
A. Guillermo Bracamonte ◽  
W. Hutchinson

: In this communication we discuss the particular electronic and quantum properties from graphene and carbon allotropes to highly conjugated carbon chemical structures from recent research. Moreover, the chemical modifications of these types of materials were analyzed against the concept of their inert properties, thus identifying their surfaces could be modified to join different properties, functionalities, and couple electronic effects, among others. Their versatility was shown based on simple chemical reactions in controlled and targeted conditions of synthesis. Variable designs could be tuned from proof of concepts to functional materials for targeted applications. In addition, it was discussed a proof of concept for Electron Transfer (ET) applications to show their electronic properties. Finally, it was analyzed the use from highly conjugated chemical structures to higher hierarchical ordered carbon structures, carbon nanotubes, graphene and carbon allotropes in electron, and opto-responsive metamaterials. Thus, new insights into multi-modal characteristics of materials were discussed.


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