scholarly journals Solid-state Synthesis of Composite Structures of Various Cu(I)-based Oxides with g-C3 N4 for Harvesting Solar Energy

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Solid State ◽  
Solar Energy ◽  
Composite Structures ◽  
Solar Spectrum ◽  
Moderate Activity ◽  
Solar Simulator ◽  
Sem Images ◽  
One Step ◽  
The Stability ◽  
Xrd Patterns

Development of novel materials for an efficient harvesting of solar energy towards applications in environment and energy sectors is an important area of research. A metal-free polymeric material, g-C3 N4 is modified with three Cu(I)- based oxides namely Cu2 O, CuVO3 , and Cu3 VO4 to extend the absorption of the solar spectrum. The composite structures are synthesized by a facile one-step solid-state reaction under inter atmosphere and atmospheric pressure. The amounts of loadings of Cu(I)-based oxides onto g-C3 N4 is varied from 2 wt.% to 10 wt.%. Powder XRD patterns showed that the graphitic structure of carbon nitride is maintained upon the construction of hybrid structures with Cu(I) oxides. SEM images show the textural transformation of the bulk structure of g-C3 N4 into nanosheets upon thermal retreatment. FT-IR spectra further confirmed the stability of g-C3 N4 observed in the XRD patterns. In comparison with the pristine g-C3 N4 , the DR-UV-Vis spectra of the modified solid powders demonstrated a clear red shift in the absorption towards higher wavelength and their better prospects in harvesting solar energy. Tauc plots derived from the DR-UV-Vis spectra showed a narrowing of the direct-allowed band gap upon modifications with Cu(I)-based oxides. The composites showed moderate activity in photocatalytic degradation of rhodamine B under irradiation from a solar simulator

scholarly journals FABRICATION AND ELECTROCHEMICAL PERFORMANCE OF LiFePO4/Ga-LLZO/Li ALL-SOLID-STATE LITHIUM BUTTON CELL

2021 ◽  
Vol 11 (1) ◽  
pp. 96-104
Author(s):  
Ruziel Larmae Gimpaya ◽  
Shari Ann Botin ◽  
Rinlee Butch Cervera
Keyword(s):  
Solid State ◽  
Solid Electrolyte ◽  
Lithium Battery ◽  
Total Conductivity ◽  
Capacity Retention ◽  
Sem Images ◽  
Button Cell ◽  
Xrd Patterns ◽  
Discharging Capacity ◽  
Good Retention

An all-solid-state Lithium button cell with Ga-doped Li7La3Zr2O12 (Ga-LLZO) as solid electrolyte, LiFePO4-based as cathode, and Li metal as anode has been successfully fabricated and characterized. The solid electrolyte was first optimized to obtain a high total conductivity. Different compositions of Li7-3xGaxLa3Zr2O12, where x =0, 0.1, 0.2, and 0.3. Li7La3Zr2O12 (LLZO) were synthesized using solid-state reaction and were characterized for its structural, morphological, electrical conductivity properties. XRD patterns of all sintered samples showed that all of the major peaks can be indexed to a cubic-phased garnet LLZO. SEM images revealed a densified sintered samples with relative densities of about 90% for all samples. Among the different studied compositions, the Ga-doped LLZO with x = 0.1 achieved the highest total conductivity of about 2.03 x 10-4 Scm-1 at 25oC, with an activation energy of 0.31 eV. From this solid electrolyte, an all-solid-state Lithium battery, 2032 button cell, was fabricated using LiFePO4-based cathode and Lithium metal as the anode. Charging and discharging characteristics were performed at 1C, 0.5C, and 0.2C rates. The results showed a good retention of coloumbic efficiency even after 50 cycles of charge and discharge. The capacity retention is about 15-20% after 50 cycles. The best performance of the coin cell battery revealed an initial specific discharging capacity of about 140 mAh/g using C/5 rate.

scholarly journals Studies on Highly Dense Pure YIG Polycrystalline Ceramics Fabricated by Tape-casting Method

2020 ◽  
Author(s):  
Chong Zhao ◽  
Yingkui Li ◽  
Xiaofei Shen ◽  
Zhijun Cao ◽  
Zhiquan Cao ◽  
...  
Keyword(s):  
Tape Casting ◽  
Solid State Reaction Method ◽  
Grain Structure ◽  
Casting Method ◽  
Forming Process ◽  
Sem Images ◽  
Polycrystalline Ceramics ◽  
Pure Phase ◽  
One Step ◽  
Xrd Patterns

Abstract Pure phase Y3Fe5O12 (YIG) ceramics was successfully produced by tape-casting forming process and one-step solid-state reaction method. With the sintering temperature above 1100 ºC, the pure phase YIG ceramics was synthesized with no YIP or Fe2O3 phase in XRD patterns. YIG ceramic sintering at 1400 ºC for 10 h showed a clear grain structure with an obvious grain boundary, and no pores were observed in the SEM images. YIG ceramics in this paper has a high relative density which was 99.8% and the saturation magnetization was 28.2 emu/g at room temperature. The hysteresis loss at temperatures of 230-360 K was smaller than 10 mJ/kg. The tan Se was nearly zero at 6~7 GHz and 11~12 GHz, showing that it can be used as a good material for microwave applications. In addition, the low values of tan and tan indicates that it may have a good electromagnetic wave absorption ability.

Phase Development and Microwave Dielectric Properties of Ba4(Sm1−yNdy)9.33Ti18O54

2007 ◽  
Vol 336-338 ◽  
pp. 255-257
Author(s):  
X.H. Yu ◽  
Dong Xiang Zhou ◽  
Shu Ping Gong ◽  
Jun Zhao ◽  
X.L. Zhang
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Microwave Dielectric Properties ◽  
Secondary Phase ◽  
Solid State Reactions ◽  
Calcination Process ◽  
Microwave Dielectric ◽  
Phase Development ◽  
One Step ◽  
Xrd Patterns

In order to study the effect of coexistence of Nd2O3 and Sm2O3 on phase development in Ba4 (Sm0.7Nd0.3)9.33Ti18O54 ceramics, the calcination process was applied in one-step and two-step way. From the XRD patterns of one-step calcinated powders, the solid-state reactions were deduced. And the results indicated the coexistence of Nd2O3 and Sm2O3 would be helpful to form secondary phase Nd2Ti2O7, which would worsen the properties. The final tested results of sintered samples confirmed the advantages of two-step calcination. The εr was improved from 72.1 to 82.4 and Q.f was improved from 7200 GHz to 8300 GHz, while τf was still near zero.

scholarly journals PEMBUATAN DAN KARAKTERISASI KATALIS TIO2/KARBON AKTIF DENGAN METODE SOLID STATE

2015 ◽  
Vol 9 (1) ◽  
pp. 34 ◽  
Author(s):  
Upita Septiani ◽  
Mega Gustiana ◽  
Safni
Keyword(s):  
Solid State ◽  
Wave Number ◽  
Composite Catalyst ◽  
Not Given ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Solid State Method ◽  
X Ray ◽  
Infra Red ◽  
Xrd Patterns

Composite catalyst of TiO2/Activated Carbon (TiO2/AC) had been synthesized with successfully by solid-state method. Synthesis was done by varying the addition of AC 5%, 10% and 15% of the mass of TiO2 was used. Composite catalyst was calcinated at temperature 400°C and characterized by Fourier Transform Infra-Red (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). FTIR spectrum show that the absorption appearedin the regionof C=C at wave number 1600-1800 cm-1, that assumed from AC. From XRD we can see that with variated of AC do not given different XRD patterns significantly, crystal structure of composite catalyst is anatase. SEM images showed that AC prevented the aglomeration of TiO2 that would expand surface area and increased catalytic activity of TiO2.

scholarly journals Sustainable One-Step Solid-State Synthesis of Antibacterially Active Silver Nanoparticles Using Mechanochemistry

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2119
Author(s):  
Mária Kováčová ◽  
Nina Daneu ◽  
Ľudmila Tkáčiková ◽  
Radovan Búreš ◽  
Erika Dutková ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Solid State ◽  
Antibacterial Properties ◽  
Absorption Spectrometry ◽  
Milling Process ◽  
Thymus Vulgaris ◽  
Tem Analysis ◽  
One Step ◽  
Thymus Serpyllum ◽  
The Stability

A combination of solid-state mechanochemical and green approaches for the synthesis of silver nanoparticles (AgNPs) is explored in this study. Thymus serpyllum L. (SER), Sambucus nigra L. (SAM) and Thymus vulgaris L. (TYM) plants were successfully applied to reduce AgNO3 to AgNPs, as confirmed by X-ray diffraction analysis, with SER being the best reducing agent, and TYM being the worst. The experiments were performed via a one-step planetary milling process, where various AgNO3:plant mass ratios (1:1, 1:10, 1:50 and 1:100) were investigated. Atomic absorption spectrometry indicated that the stability of the mechanochemically produced AgNPs increased markedly when a sufficiently large quantity of the reducing plant was used. Furthermore, when larger quantities of plant material were employed, the crystallite size of the AgNPs decreased. TEM analysis revealed that all AgNPs produced from both AgNO3:plant ratios 1:1 and 1:10 exhibit the bimodal size distribution with the larger fraction with size in tens of nm and the smaller one below 10 nm in size. The antibacterial activity of the produced AgNPs was observed only for AgNO3:plant ratio 1:1, with the AgNPs prepared using SER showing the greatest antibacterial properties.

Studies Regarding the Architectural Design of Various Composites and Nanofibres Used in Dental Medicine

2018 ◽  
Vol 69 (2) ◽  
pp. 328-331
Author(s):  
Irina Gradinaru ◽  
Leonard Ignat ◽  
Cristina Gena Dascalu ◽  
Laurentiu Valentin Soroaga ◽  
Magda Ecaterina Antohe
Keyword(s):  
Composite Structures ◽  
Architectural Design ◽  
Dental Restoration ◽  
Fibrillar Structure ◽  
Fiber Post ◽  
Fiber Glass ◽  
Full Agreement ◽  
Sem Images ◽  
Structural Modifications ◽  
New Formulation

The aim of this study was represented by the definition and testing of a new formulation strategy and the functionality of composite materials, while ensuring the optimization of the relevant properties for the dental restoration processes through the use of precise techniques of characterization, the modification and functionality of the components in view of obtaining results that are characterized by an optimum biomechanical and bioactive relation, in full agreement with the particularities of the dental structure that requires restoration. In view of obtaining new resistant composite structures we made a number of 10 samples including extracted teeth with various losses of dental substance and the structural modifications included 3 types of composites, whose structure was improved by the introduction of inorganic fillings based on hydroxyapatite and silver nanoparticles. All these structures were reinforced with two types of fibers, Reforpost fiber glass kit (Angelus) and Fiber post Schulzer Pre-silanized; With regard to the use of composite structures improved by HA addition, we notice a slight lacunary structure on the SEM images due to the properties of HA, an aspect present at much smaller dimensions in the silver � HA mix. The size of the grains associated with their continuous uniformity and adherence for the fibrillar structure stands out at the samples with hydroxyapatite, the first place as uniformity and adherence going to the composite of the nanofiller technology category.

Insights into Potent Therapeutical Antileukemic Agent L-glutaminase Enzyme Under Solid-state Fermentation: A Review

2020 ◽  
Vol 21 (3) ◽  
pp. 211-220 ◽  
Author(s):  
Chandrasai Potla Durthi ◽  
Madhuri Pola ◽  
Satish Babu Rajulapati ◽  
Anand Kishore Kola
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Food Industry ◽  
Energy Requirement ◽  
Production Studies ◽  
Wide Range ◽  
Hybridoma Technology ◽  
Bacteria And Fungi ◽  
The Stability ◽  
Glutaminase Activity

Aim & objective: To review the applications and production studies of reported antileukemic drug L-glutaminase under Solid-state Fermentation (SSF). Overview: An amidohydrolase that gained economic importance because of its wide range of applications in the pharmaceutical industry, as well as the food industry, is L-glutaminase. The medical applications utilized it as an anti-tumor agent as well as an antiretroviral agent. L-glutaminase is employed in the food industry as an acrylamide degradation agent, as a flavor enhancer and for the synthesis of theanine. Another application includes its use in hybridoma technology as a biosensing agent. Because of its diverse applications, scientists are now focusing on enhancing the production and optimization of L-glutaminase from various sources by both Solid-state Fermentation (SSF) and submerged fermentation studies. Of both types of fermentation processes, SSF has gained importance because of its minimal cost and energy requirement. L-glutaminase can be produced by SSF from both bacteria and fungi. Single-factor studies, as well as multi-level optimization studies, were employed to enhance L-glutaminase production. It was concluded that L-glutaminase activity achieved by SSF was 1690 U/g using wheat bran and Bengal gram husk by applying feed-forward artificial neural network and genetic algorithm. The highest L-glutaminase activity achieved under SSF was 3300 U/gds from Bacillus sp., by mixture design. Purification and kinetics studies were also reported to find the molecular weight as well as the stability of L-glutaminase. Conclusion: The current review is focused on the production of L-glutaminase by SSF from both bacteria and fungi. It was concluded from reported literature that optimization studies enhanced L-glutaminase production. Researchers have also confirmed antileukemic and anti-tumor properties of the purified L-glutaminase on various cell lines.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

scholarly journals Solid-State Redox Kinetics of CeO2 in Two-Step Solar CH4 Partial Oxidation and Thermochemical CO2 Conversion

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 723
Author(s):  
Mahesh Muraleedharan Nair ◽  
Stéphane Abanades
Keyword(s):  
Solid State ◽  
Solar Energy ◽  
Kinetic Models ◽  
Oxygen Carrier ◽  
Co2 Conversion ◽  
Oxidation Reactions ◽  
Redox Kinetics ◽  
Concentrated Solar Energy ◽  
Ceria Reduction ◽  
Kinetics Of

The CeO2/CeO2−δ redox system occupies a unique position as an oxygen carrier in chemical looping processes for producing solar fuels, using concentrated solar energy. The two-step thermochemical ceria-based cycle for the production of synthesis gas from methane and solar energy, followed by CO2 splitting, was considered in this work. This topic concerns one of the emerging and most promising processes for the recycling and valorization of anthropogenic greenhouse gas emissions. The development of redox-active catalysts with enhanced efficiency for solar thermochemical fuel production and CO2 conversion is a highly demanding and challenging topic. The determination of redox reaction kinetics is crucial for process design and optimization. In this study, the solid-state redox kinetics of CeO2 in the two-step process with CH4 as the reducing agent and CO2 as the oxidizing agent was investigated in an original prototype solar thermogravimetric reactor equipped with a parabolic dish solar concentrator. In particular, the ceria reduction and re-oxidation reactions were carried out under isothermal conditions. Several solid-state kinetic models based on reaction order, nucleation, shrinking core, and diffusion were utilized for deducing the reaction mechanisms. It was observed that both ceria reduction with CH4 and re-oxidation with CO2 were best represented by a 2D nucleation and nuclei growth model under the applied conditions. The kinetic models exhibiting the best agreement with the experimental reaction data were used to estimate the kinetic parameters. The values of apparent activation energies (~80 kJ·mol−1 for reduction and ~10 kJ·mol−1 for re-oxidation) and pre-exponential factors (~2–9 s−1 for reduction and ~123–253 s−1 for re-oxidation) were obtained from the Arrhenius plots.

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