Effects Of Variations In Composition Research Articles

Off-stoichiometric NaxV2(PO4)3 as cathode material for sodium-ion batteries

The NASICON-type compound Na3V2(PO4)3 (NVP) has garnered significant attention as a promising cathode material for sodium-ion batteries. However, the practical application of the NVP cathode still face challenges due to its intrinsic limitation of electronic conductivity and cycling stability. Herein, a novel off-stoichiometric NaxV2(PO4)3 cathode is synthesized, and the effects of compositional variations on both structural stability and electrochemical properties are investigated. Particularly, the optimized Na3.3V2(PO4)3 electrode exhibits superior cycling stability with a capacity retention of 86.7 % after 400 cycles, and excellent rate capability, achieving a capacity of 90 mAh g−1 at 5 C. Through a combination of electrochemical analysis and first-principle calculations, it is elucidated that the excess Na+ content within the structure effectively expands lattice volume, thereby mitigating migration barriers for enhanced ion diffusivity.

Effects of Composition Variations on Mechanochemically Synthesized Lithium Metazirconate-Based Ceramics and Their Resistance to External Influences

The study examines the influence of variations in the compositions of components for the production of lithium-containing ceramics based on lithium metazirconate obtained by the method of mechanochemical grinding and subsequent thermal sintering. For component variation, two compositions were used, consisting of zirconium dioxide (ZrO2) and two distinct types of lithium-containing materials: lithium perchlorate (LiClO4·3H2O) and lithium carbonate (Li2CO3). Adjusting the concentration of these components allowed for the production of two-phase ceramics with varying levels of impurity phases. Using X-ray phase analysis methods, it was determined that the use of LiClO4·3H2O results in the formation of a monoclinic phase, Li2ZrO3, with impurity inclusions in the orthorhombic phase, LiO2. On the other hand, when Li2CO3 is used, the resulting ceramics comprise a mixture of two phases, Li2ZrO3 and Li6Zr2O7. During the studies, it was established that the formation of impurity inclusions in the composition of ceramics leads to an increase in the stability of strength properties with varying mechanical test conditions, as well as stabilization of thermophysical parameters and a decrease in thermal expansion during long-term high-temperature tests. It has been established that in the case of two-phase ceramics Li2ZrO3/Li6Zr2O7 in which the dominance of the Li6Zr2O7 phase is observed during high-temperature mechanical tests, a more pronounced decrease in resistance to cracking is observed, due to thermal expansion of the crystal lattice.

The Effect of Composition, Pyrolysis Temperature and Adhesive Concentration on the Proximate Content and Calorific Value of Biobriquettes from Durian Skin, Corn husk and Fish Bones Waste

Briquettes are an alternative energy derived from biomass. Biomass material can be obtained from plantation waste such as durian peel, agricultural waste such as corn husk and waste from the fisheries sector such as fish bones. Waste of corn husks, durian peel and fish bones have the potential to become biomass material as an alternative energy. The aim of this research is to analyze the effect of variations in composition, pyrolysis temperature and adhesive concentration on the quality of biobriquettes and emissions resulting from the combustion process. The dried waste materials is then pyrolyzed for 4 hours at 350 ℃ and 500 ℃. Proximate testing was carried out to determine the quality of the biobriquettes. The parameters analyzed in this test include moisture content, ash content, volatile matter content, bound carbon content and heating value. The results of the study revealed that the best sample variations were found in briquettes with a composition of 50% durian peel [T1] [c2] : 50% corn husk with a pyrolysis temperature of 350℃ and an adhesive concentration of 7%. The level of CO emissions produced when burning briquettes is 1,700 mg/Nm3 and SO2 is 0.741 mg/Nm3.

Effect of Variation in Pineapple Leaf Fiber Composition with Polyurethane Matrix in Composite Panels on Acoustic Properties and Porosity

Noise can cause medical, psychological, and environmental disturbances. One of the efforts to reduce noise is by using acoustic materials. Acoustic materials can be made using natural fiber composites. This study uses pineapple leaf fiber as fiber and polyurethane as a matrix that will be formed into a sound-absorbing composite panel. This study aims are to determine the effect of variations in the composition of pineapple fiber-reinforced composites with polyurethane matrix on acoustic properties and porosity, determine the effect of frequency on acoustic properties, and determine the relationship between porosity and acoustic properties. The method used in this research uses a characterization tool in the form of a one-microphone impedance tube and porosity test equipment. Composite panels are made by varying the composition of pineapple leaf fibers with polyurethane matrix with the ratio of pineapple leaf fiber composition to polyurethane matrix, namely 50%: 50%, 60%: 40%, 70%: 30%, 80%: 20% and 90%: 10%. Based on the research, it was found that the more the amount of pineapple leaf fiber composition is used, the absorption coefficient, sound transmission loss, and prostitution will increase while the reflection coefficient decreases. The higher the frequency used, the absorption coefficient and sound transmission loss will increase while the reflection coefficient decreases for all frequencies. The relationship between porosity and acoustic properties is that the higher the porosity, the absorption coefficient and sound transmission loss will increase while the reflection coefficient decreases

Development of ZnO-GO-NiO membrane for removal of lead and cadmium heavy metal ions from wastewater

The presence of heavy metal (HM) ions, such as lead, cadmium, and chromium in industrial wastewater discharge are major contaminants that pose a risk to human health. These HMs should separate from the wastewater to ensure the reuse of the discharged water in the process and mitigate their environmental impacts. The distinctive mechanical properties of 2D graphene oxide (GO), and the antifouling characteristics of metal oxides (ZnO/NiO) nanoparticles combined to produce composites supporting special features for wastewater treatment. This study employed solution casting and phase inversion methods to synthesize PSF-based GO, ZnO-GO, and ZnO-GO-NiO mixed matrix membranes and the effects of variation in composition on the removal of lead (Pb2+) and cadmium (Cd2+) ion was examined. Several characterization techniques including X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray, and Fourier transform infrared spectroscopy were applied to analyze the synthesized NPs and MMMs. The composite membranes were also analyzed in terms of their porosity, permeability, hydrophilicity, surface roughness, zeta potential, thermal stability, mechanical strength, and flux regeneration at various transmembrane pressures (2–3 kgcm−2), and pH value (5.5). The highest adsorption capacities were measured to be 308.16 mg g−1 and 354.80 mg g−1 for Pb (II) and Cd (II), respectively, for membrane (M4_A) having 0.3 wt% of ZnO-GO-NiO nanocomposite, at 200 mg L−1 of feed concentration and 1.60 mL min−1 of permeate flux. The Pb (II) and Cd (II) adsorption breakthrough curves were created, and the results of the experiment were compared with the data of the Thomas model.

Effects of composition variation and hydrogenation on magnetocaloric properties of the (Gd1-xTbx)Ni (x = 0.1; 0.9) compounds

To identify promising magnetic refrigerant materials, we have studied the influence of composition variations and hydrogenation on the magnetocaloric effect (MCE) of the (Gd1-xTbx)Ni compounds. The end compositions of the series, Gd0.9Tb0.1Ni and Gd0.1Tb0.9Ni crystallize in orthorhombic CrB-type and monoclinic TbNi-type structures, respectively. Hydrogenation boosts the unit cell volume of (Gd,Tb)Ni by more than 20 % upon absorption of 4 at.H/f.u. Hydrogen absorption changes the structure type from TbNi to the CrB-type in Gd0.1Tb0.9Ni. Decrease of the Curie temperature in hydrides reaches ∼ 60 K. The magnetocaloric effect in (Gd,Tb)NiHy (y = 0 and 4) obtained by indirect method in the vicinity of TC revealed similar values of the maximum of specific isothermal entropy change -ΔST = 20.5 J kg−1 K−1 for Gd0.9Tb0.1Ni and its hydride Gd0.9Tb0.1NiH4 at μ0ΔH = 7 T. We show that the controlled synthesis of hydrides allows us to tailor the magnetocaloric effect in the multicomponent rare earth intermetallics and obtain materials with largely different TCs but with the same MCE values that are attractive for use in low-temperature magnetic cooling applications.

Microstructure correlated optical, electrical and mechanical characterizations of (Bi1-xSbx)2Te3: Effect of compositional variations on different properties

Nanocrystalline rhombohedral (Bi1-xSbx)2Te3 (with x = 0, 0.25, 0.5, 0.75, 1) powders are synthesized by a facile one-pot mechanical milling technique using elemental Bi, Sb, and Te powders, taken in different proportions within 3 h of milling. The Rietveld refined X-ray diffraction (XRD) patterns of the fabricated samples reveal the compositional variations of different microstructural parameters like crystallite size, lattice strain, and lattice parameters. The included impurity percentages of Bi and Sb explain the variation of lattice parameter a, whereas, the antisite defects are well interpreted with the change in lattice parameter c. The r.m.s. lattice strain is consistent with the formulation of different antisite defects acting as either n-type or p-type doping within the materials (Bi1-xSbx)2Te3. The microstructure is also revealed from the field-emission scanning electron microscope (FESEM) image and energy dispersive X-ray (EDX) spectrum and compared with the results obtained from the XRD pattern analysis. The narrow bandgaps of the materials are determined from the Fourier transform infrared (FTIR) spectra, and the correlation with the microstructure establishes their changes with the compositional x value. Here, both the blue and red shifts in bandgap with particle size variations are observed and explained. The positions of the conduction and valence bands are determined with composition variations (x). The non-Debye type, thermally activated conduction process of the semiconducting materials is confirmed from the ac electrical study of the samples at room and high temperatures. The variation of electrical conductivity with different alloying concentrations and temperatures is explained in terms of their particle size and density of antisite defects. The conduction mechanism is found to be a small polaron hopping model. The Vickers microhardnesses of the samples are measured and explained by correlating with the microstructural parameters. The Meyer's law establishes the normal indentation size effect (ISE). The microhardness of the materials partially supports the conductivity results.

Optimization of Red Sand Particle Size and Composition in Mixture with Ordinary Sand to Enhance Concrete Quality

Abstract In this study we determined the effect of variations in composition and particle size of Red Sand (RS) grains on the quality of concrete. Concrete was prepared as cubes of 15 cm3 with a composition of cement, sand and gravel in a ratio 1:2:3 and water to cement ratio of 0.5. Variations of RS (fine aggregate) composition are 0 %, 5 %, 10 %, 15 %, 20 % of the weight and red sand grain particle size were prepared as 80 mesh, 100 mesh, 120 mesh. Mechanical properties of the maximum concrete pressure strength test at a composition of 5 % along with a decrease in the size of the red sand grain size of 100 mesh and 120 mesh RS 100-5 and RS 120-5 with pressure forces of 35.4 MPa, and 35.5 MPa, respectively. On the other hand, the red sand with 80 mesh grain size have maximum pressure force in a composition 10 % RS 80-10 is 34.6 MPa. It is considered the addition of red sand fine aggregate has an impact on improving the quality of concrete.

Preparation and Characterization of Ceramic Membrane Composition Variations in Pome Waste Treatment

Palm Oil Mill Effluent (POME) is waste generated by the palm oil industry consisting of solid, liquid and gaseous wastes. POME is decomposed in sewage ponds and allowed to decompose naturally. The residual waste generated by this industry is non-toxic but has high polluting power. To overcome this, it is necessary to treat waste by making ceramic membranes. The composition materials needed are clay, zeolite, sodium carbonate and boric acid. The manufacturing method is through the printing and combustion stages at a temperature of 900oC. The results showed that there was an effect of compositional variations on the quality of the final product, namely TSS rejection % 93.355 with a flux value of 0.2474 (L/m2min). From the parameter values obtained, it proves that the ceramic membrane is able to process POME with satisfactory effective results. The quality standard of palm oil liquid waste is in accordance with South Sumatera governor regulation number 8 of 2012 concerning quality standard of liquid waste for industrial, hotel, hospital, domestic and coal mining activities

Shock tube study of natural gas oxidation at propulsion relevant conditions

Global climate change and rising crude oil prices have motivated search of clean, sustainable and economic fuel. Methane, having the highest hydrogen to carbon ratio is ideally the best option towards carbon neutral emissions and reduce greenhouse gas emissions. However, there the economic benefits are minimal when using pure methane because of purification costs. Natural gas primarily consists of methane but with appreciable amounts of C2C4 alkanes which significantly impact oxidation performance, especially when compared to pure methane at high pressures and temperatures, studies of natural gas have been scarce and there is new interest in studying natural gas for its application to propulsion devices. This single pulse shock tube study investigates the effect of natural gas composition on species yields as a function of temperature at various stoichiometric conditions (φ ≈ 0.5, 1.0, 2.0) and high pressure (240 atm) over a nominal reaction time of 2.5 ms. The experimentally measured speciation results for one real natural gas sample from Boise, ID (USA) and a reference natural gas sample are compared to species yield predictions using well established chemical kinetic mechanisms, to check the feasibility of using these mechanisms in the design of propulsion devices. The chemical kinetic simulations are carried out using the constant pressure approach as well as the changing pressure approach which considers the exact measured pressure change in the shock tube. The experiments provide a large speciation data set for optimizing chemical kinetic mechanisms for natural gas applications and to understand the effect of composition on natural gas chemical kinetics. The predictions vary significantly between models tested and effect of composition variation was evident. Aramco Mech 3.0 could predict the experiments almost perfectly, especially at fuel rich conditions.

Effect Of Composition Variation With Depth On Volatile Oil Reservoirs

It has been known that the distribution of hydrocarbon components in a fluid column is affected of gravity. Many authors have shown the effect of composition variation within a hydrocarbon column due to gravity. In thick reservoirs as the depth increases, the mole fraction of the lighter hydrocarbon decreases, whereas the heavy fraction increases. These variations may affect reservoir fluid properties considerably. In studying reservoir processes, especially with miscible displacements, it is essential to have of underlying mechanisms. In this paper, we investigate the effect of composition variation with depth on volatile oil under depletion and miscible gas processes. A ternary diagram was used to identify the process displacement mechanisms at different locations. A new efficient compositional simulationapproach was used to model the volatile oil reservoir bahaviour. It was shown that the decreasing light component with depth caused different miscible displacement processes as the oil composition move toward limiting tie line in the ternary diagram. Saturation and reservoir pressures variation with depth were not linear in a thick reservoir. This non linearity increased with the increased in volatility of the oil. In the case of depletion, the concentration of light component decreased below its original composition in the produced layers. In vaporising-gas drive the light component gradually vaporized from the bottom to the top of reservoir, whereas the intermediate component decreased below its original composition from the bottom to the top of the reservoir

Effects of composition variation and site disorder on the magnetic interactions in Ru2Fe(Si1-xGex) alloys

X-ray diffraction studies on arc melted Ru2Fe(Si1-xGex) (0 ≤ x ≤ 1) alloys did not show the characteristic (111) and (200) super-lattice peaks of the stable L21 structure of full Heusler alloys. The alloy with x = 0 exhibited antiferromagnetic behaviour. However, with increase in x, the alloys became ferromagnetic. In order to understand the origin of the novel magnetic behavior of these alloys and its correlation with their crystal structure, ab initio study was carried out using spin-polarized relativistic Korringa-Kohn-Rostoker Green’s function method. The study shows that the antiferomagnetism in the alloy with x = 0 is due to the presence of B2 disorder. Due to this, the 2nd nearest neighbour (NN) exchange interaction between the Fe atoms at proper and improper sites, respectively, becomes strongly antiferromagnetic which dominates over the 1st NN ferromagnetic exchange interaction. With increase in x, the alloys become ferromagnetic with an improvement in L21 ordering which in turn makes the 1st NN interaction strongly ferromagnetic. The electronic structure calculations show no half metallic gap in either spin direction for all the alloys. Comparison of experimental and theoretically estimated properties of Ru2Fe(Si1-xGex) alloys provides insight to the variation in the magnetic interaction with the composition and the disorder present in the alloys.

Effect of compositional variation of dental MTA cements on setting time

치과용 MTA (Mineral Trioxide Aggregate) 시멘트의 긴 경화시간은 임상사용에서 큰 단점이다. 본 연구는 시판되는 9종 MTA제품의 경화시간을 ISO 6876:2012 표준방법에 따라 5회 반복 측정하였다. 평가된 재료는 ProRoot MTA (PR), Ortho MTA (Ortho), Retro MTA (Retro), Endocem MTA (Endocem), Endoseal MTA (Endoseal), One-Fil (OF), MTA Cem (MC), EZ-Seal (EZ), 및 Biodentine (BD) 이었다. 경화시간에 미치는 조성의 영향을 평가하기 위하여 XRD 및 XRF 분석을 시행하였다. 경화시간 결과값 사이의 유의성은 비모수 검정 방법인 Kruskal-Wallis 분석 후 Duncan 사후검정을 통해 다중분석하였다. 경화시간은 PR > EZ > OF > Ortho > Retro > MC > Endoseal > BD > Endocem 순 이었다 (p < 0.001). PR은 가장 긴(369.4 분), Endocem은 가장 짧은(2.4 분) 경화시간을 보였다. Endocem (2.4 분), BD (16.0 분) 및 Endoseal (47.0 분)은 탄산칼슘(calcium carbonate)를 함유하였고, 그 다음으로 경화시간이 짧았던 MC (48.8 분), Retro (43.6 분), Ortho (65.0 분) 및 OF (165.4 분)는 알루민산 이석회(dicalcium aluminate)를 함유하였다. EZ (182.4 분)는 초기강도 형성에 기여하는 규산 삼석회(tricalcium silicate)보다는 규산 이석회(dicalcium silicate)가 주 결정상을 이뤘고, 황산칼슘(calcium sulfate)을 함유하였다. 가장 짧은 경화시간을 보인 Endocem은 가장 작은 d90 입도(6.12 μm)를 보였다. 본 연구결과는 MTA 시멘트의 경화시간 조절을 위한 조성 개발과 각 임상 증례에 적합한 경화시간을 갖는 제품의 선택에 도움이 될 것으로 사료된다.

Effect of Compositional Variation on the Microstructural Evolution and the Castability of Al–Mg–Si Ternary Alloys

Effect of Compositional Variation on the Microstructural Evolution and the Castability of Al–Mg–Si Ternary Alloys

Effect of variations in Composition and Sintering Temprature on Mechanical Properties Ceramic Membrane with Bentonite, Sinabung Volcanic Ash and Carbon Active

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Investigation of Structural and Thermoelectric Properties of Bismuth Selenide Thin Films

Background: Thermoelectric material with high performance and low cost is the basic need of today. Bismuth selenide is a thermoelectric material. A set of bismuth selenide thin films having different stoichiometry ratios varying Bi/Se ratio from 0.123 to 0.309 have been prepared. Objective: The present work deals with the synthesis and characterization of various thin films of bismuth selenide. The thermoelectric properties of thin films were also investigated. The aim of this work is to investigate the effect of composition ratio on the structural and thermoelectric properties and to find out the best stoichiometry ratio of bismuth selenide thin films that can be used in the application of thermoelectric devices. Methods:: A set of bismuth selenide thin films having different elemental compositions were prepared by employing the thermal evaporation technique. The crystal structure and elemental composition of thin films were investigated by XRD and EDAX, respectively. The roughness of films was analyzed by AFM. The thermoelectric properties of various thin films were also measured. Results: XRD spectrum confirms the formation of phases formed in thin films which slightly matched with standard data. AFM results indicated that the surface of films was smooth and nanoparticles were generated on the surface. AFM results indicated that the surfaces of annealed thin films were smoother than as-deposited thin films. Seebeck coefficient was found negative throughout the temperature range. The power factor was also calculated by the Seebeck coefficient and results revealed the effect of composition ratio on Seebeck coefficient, electrical conductivity, and power factor. Thin films having a composition ratio of 0.182 exhibited the highest power factor. Conclusion: This study provides relevant basic information on the thermoelectric property of thin films, as well as presents the effect of compositional variation on thermoelectric measurements. From the application point of view in the thermoelectric devices, the best stoichiometric thin films out of four prepared thin films have been presented.

Unraveling the valence states of manganese ions and the effects of composition variation and post-processing in YGG1-x-LuGGx:Mn garnet optical sensor

Transition metal manganese ions possess multiple valence states, and the change of local coordination environments would seriously influence their energy-level schemes and luminescence properties. Herein, YGG1-x-LuGGx:Mn garnet phosphors were proposed, the valence states of manganese ions and the effects of composition variation and post-processing were investigated systematically. Based on the temperature-dependent photoluminescence (PL) spectral analysis and XPS survey, the existing manganese ions are verified as Mn3+ and Mn4+. And both co-doping of Zr4+ ions and reduction processing can enhance and weaken the emissions of Mn3+ and Mn4+, respectively. Besides, introducing lutetium ions causes a PL blueshift of the two kinds of manganese ions and raises the resistance to thermally induced fluorescence quenching of Mn3+. Moreover, as for LuGG:Mn, the reduction treatment gives rise to a new garnet phase with a larger lattice parameter than that of the LuGG phase because of the existence of the LuGa antisite-defects. Finally, the combination of Mn3+ and Mn4+ ions demonstrates outstanding temperature sensing performance, further verifying the application potential of YGG1-x-LuGGx:Mn phosphors in optical thermometry.

Effect of compositional variation on physico-chemical and structural changes in infant formula during storage

Formation of 5-hydroxymethyl furfural (HMF) and acetic acid, browning index (BI) and conformational changes in protein structure in infant formula (IF) powders were studied during storage at 25 and 45 °C and relative humidity (RH) range of 11–65%. Three powders with nutritional composition representing stages 1 (IF1), 2 (IF2) and 3 (IF3) of IF were studied. HMF formation in IF powders increased with increasing storage temperature and RH; the increase was highest in IF3 samples. BI showed a linear correlation with HMF concentration, irrespective of variation in product composition. Reduction in pH during storage could be associated with acetic acid formation as a result of Maillard reactions; these were also the likely cause of changes in protein conformation during storage, with decreases in α-helical structure and increases in β-sheets and β-turns observed. Overall, variation in levels of macro-nutrients influenced the degree of change in the commercial IF powders.

Variation in Composition of Aluminium Alloy Al6463 on Wear Characteristics and Compressive Strength

Aluminium is one of the widely used metals in industrial sector owing to its specific features and its commercial production started in late 19th century. In its natural form it is combined with oxygen and other elements and is the third most abundant metal in the earth’s crust. It can be machined easily and has a Face Centred Cubic (FCC) structure. Aluminium alloys are an attractive alternative to ferrous materials for tribological applications due to their low density and high thermal conductivity. The microstructure of aluminium alloys can be modified and mechanical properties can be improved by alloying, cold working and heat treatment. The present work mainly focuses on the study of the effect of variation in composition on the wear characteristics and compressive strength of aluminium alloy Al6463 by varying the compositions of the two major alloying elements, Magnesium (Mg) and Silicon (Si) in the alloy. Four specimens of the aluminium alloy Al6463 are prepared each for Magnesium composition varying b/w (0.5 to 0.875%) and Silicon composition varying b/w (0.2 to 0.575%). Wear and compression tests were carried out as per ASTM standard. The results of the wear test indicate that the least wear rate was obtained for specimens of 0.750% Mg and 0.575% Si composition of the alloy Al6463 at a higher load of 1.5 kg. Also, the compression test results indicate that the specimens with 0.750% Mg and 0.575% Si compositions of the alloy Al6463 exhibit better compressive strength.

The effect of composition variations on the response of steels subjected to high fluence neutron irradiation

A set of low alloy model reactor pressure vessel steels, with systematic variations in their Mn, Ni, and Si contents, were neutron-irradiated to high fluence (1.4 × 1020 n/cm2) in the Advanced Test Reactor at Idaho at 290°C and a flux of 3.6 × 1012 n/cm2s. The alloys were analysed using atom probe tomography and solute clusters were observed in each alloy, including in one alloy that contained low nominal levels of Mn (0.04 at. %) and Si (0.06 at. %). Changes in the mechanical properties of the alloys were correlated with cluster volume fractions. Whilst the effect of nominal composition was observed to influence cluster composition, cluster nucleation site was not observed to affect composition. Several grain boundaries were also analysed and the segregation behaviour of certain elements is discussed.