scholarly journals Investigating the Effect of CuO/NiO and CuO/CoO Relative Composition on the Reduction Time of (CuO)x-(NiO)(1-x) and (CuO)x-(Co3O4)(1-x) with Methane Gas as the Reducing Agent in the Synthesis of Nano-bimetallic Nix-Cu(1-x) and Cux-Co(1-x)

Author(s):  
Hassan Ghanbarabadi ◽  
Behnam Khoshandam

In this paper, the reduction duration of (CuO)x-(NiO)(1-x) and (CuO)x-(Co3O4)(1-x) binary mixtures was studied using thermogravimetric method. The reduction reaction was performed using copper, nickel and cobalt oxides as metal precursors and methane gas as the reducing agent, under atmospheric pressure. The products as well as the raw materials were characterized and analyzed using X-Ray diffraction (XRD) and Energy Dispersive Spectroscopy (EDS). Initially, CoO, NiO and CuO were transformed to Co, Ni and Cu through reduction reactions with 23 Vol.% of methane at 830 °C. Results demonstrated that the reduction times of NiO, CoO and CuO NPs with CH4 at 830 °C were 14, 39 and 47 min, respectively. EDS and XRD analysis indicated that more than 97 % of copper, nickel and cobalt oxides were transformed to copper, nickel and cobalt NPs. The reaction time of (CuO)x-(NiO)(1-x) and (CuO)x-(Co3O4)(1-x) binary mixtures with methane was investigated to evaluate the effect of CuO (x=0, 0.4, 0.6, 1) relative composition. In addition, the reaction time of ternary mixture of (NiO)0.6-(CuO)0.2-(Co3O4)0.2 with methane gas was also studied.

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Jingzhi Wu ◽  
Min Qiao ◽  
Zhifeng Lyu ◽  
Qianping Ran

Using maltodextrin (MD) of different dextrose equivalent (DE) values, 1,3-propanesultone, and maleic anhydride as raw materials, a novel binary modified maltodextrin (BMMD) was synthesized and further applied as a water-reducing agent. Its structure was characterized by Fourier transform infrared (FT-IR) and UV. The rheological behavior of the sample solution and strengths for concrete were also determined and the adsorption was tested by TOC. The influence of the process parameters to degree of substitution (DS) and the dosage on the fluidity of cement paste were investigated. The results show that the optimal conditions of sulfonation were the MD of DE 15, m (sulfonated agent)/m (MD) of 1.4, the catalyst amount of 1% by mass MD, and the reaction time of 12 h; the optimal conditions of esterification were m (esterified agent)/m (SMD) of 0.6, the reaction temperature of 90°C, and the reaction time of 4 h. The optimal dosages of sulfonated maltodextrin (SMD) and BMMD were 0.475% and 0.45%, respectively. In this dosage, the main dispersion capacity of BMMD attributes to two kinds of anchoring groups (SO3-  &  COO-) and the appropriate molecular weight of MD.


2015 ◽  
Vol 1087 ◽  
pp. 370-373 ◽  
Author(s):  
Suhaina Ismail ◽  
Hashim Hussin ◽  
Syed Fuad Saiyid Hashim ◽  
Norazharuddin Shah Abdullah

Manganese-bamboo sawdust leached residue (MBLR) is characterized by X-ray diffraction (XRD). The aim of this study is to evaluate the effects of leaching reaction time on the MBLR. The initial solids of low grade manganese (LGMO) ore and bamboo sawdust (BSD) as reducing agent, as well as the leach residues, were characterized. XRD analysis showed that the pyrolusite peak has not been found in the LGMO leached residue and the peak corresponding to quartz and goethite has diminished, compared to XRD peaks of initial LGMO. The calculated crystallinity of the BSD residue has decreased from 56.12% to 52.65%. This indicated that the crystalline portion of cellulose was readily hydrolyzed during the leaching process.


2020 ◽  
Vol 16 (8) ◽  
Author(s):  
Jiabao Cao ◽  
Baoxin Lu ◽  
Dongjie Zhang ◽  
Longkui Cao ◽  
Xia Wang ◽  
...  

AbstractThe present study was carried out to produce a high quality puffed infant rice cereal from rice and mung bean through extrusion technology. Experiments were designed using 3 independent variables (i. e. 14–18% feed moisture, 400–550 r/min screw speed and 125–175 °C barrel temperature) and 3 response variables (i. e. bulk density, water solubility index and degree of gelatinisation) at five different levels of central composite rotatable design (CCRD). The results of optimization demonstrated that 14% feed moisture, 400 r/min screw speed and 175 °C barrel temperature could generate rice-mungbean extrudates with desirable functional properties. The selected extrudate samples were further examined using scanning electron microscope (SEM), rapid viscosity analyzer (RVA), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD) analysis, in vitro digestibility and fundamental nutrient analysis. Notably, the initial oval-shaped particle structure of starch in the raw materials disappeared, the surface debris and roughness increased, and the density decreased. The time required for the gelatinization of puffed infant rice cereal was the shortest, which was in agreement with the positioning of ready-to-eat weaning food for infants. Moreover, the puffed infant rice cereal displayed higher peak viscosity and breakdown value, smaller retrogradation value and greater top taste value compared to the commercial infant rice cereal. Besides maintaining the initial characteristic peak of starch, the puffed infant rice cereal demonstrated characteristic absorption peaks of COO- in the vicinity of 1546 cm−1 and 1437 cm−1, indicating the formation of carboxylate during extrusion. In addition, the puffed infant rice cereal exhibited firm diffraction peaks at the diffraction angles of 7.4°, 12.5° and 20.5°, indicating that a certain amount of starch changed from type A to type V. Furthermore, the digestive rate of puffed infant rice cereal was higher than that of commercial infant cereal (90.21 versus 86.96%, respectively; p < 0.05). Altogether, our findings reveal that the developed puffed infant rice cereal meets the standards set by the Codex Alimentarius Commission (CAC; 74-1981).


2016 ◽  
Vol 9 (2) ◽  
pp. 119 ◽  
Author(s):  
Marjan Erfani ◽  
Hedayat Sahraei ◽  
Zahra Bahari ◽  
Gholam Hossein Meftahi ◽  
Boshra Hatef ◽  
...  

<strong></strong><p><strong>BACKGROUND:</strong> Time change (which can lead to sleep duration decrements) can lead to brain dysfunction if repeated. In the present study, cognitive functions of the volunteers were evaluated before and after the time changes in Tehran.</p><p><strong>METHODS:</strong> Eleven, voluntary healthy persons (21±2 year old) were evaluated for their cognitive functions including sustain attention, reaction time, and mental fatigue twenty-one days before the time changes and thirty-eight days after time change using PASAT software. In addition, plasma cortisol level was measured before and after the time changes.</p><p><strong>RESULTS:</strong> After the time changes salivary cortisol concentration increase, but general mental health was decreased. Sustain attention was shortened after time change which was significantly different compared with before the time changes. Reaction time was increased after the time changes in comparison with the before the time changes, but was not statistically significant. In addition, mental fatigue was increased after the time changes.</p><p><strong>CONCLUSION:</strong> It seems that time change may reduce brain cognitive functions which are manifested by general mental health, sustain attention reduction, reaction time as well as mental fatigue.</p>


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4614
Author(s):  
Konrad Walkowiak ◽  
Izabela Irska ◽  
Agata Zubkiewicz ◽  
Zbigniew Rozwadowski ◽  
Sandra Paszkiewicz

The growing ecological awareness of society created the tendency to replace petrochemically based materials with alternative energy carriers and renewable raw materials. One of the most requested groups of polymer materials with significant technological importance is thermoplastic elastomers (TPE). They combine the properties of elastomers such as flexibility with the typical properties of thermoplastics, like easy processing. Herein, one compares the influence of rigid segments on the properties of copoly(ester-ether). Thermoplastic polyesters based on bio-1,6-hexanediol and terephthalic (T), furanic (F), and napthalate (N) diesters, i.e., PHT, PHF, and PHN, were obtained employing melt polycondensation. Additionally, to grant elastic properties of polyesters, systems containing 50 wt.% of bio-based polyTHF®1000 (pTHF) with a molecular mass of 1000 g/mol, have been prepared. The composition and chemical structure have been determined by 1H nuclear magnetic resonance (NMR) and Fourier transformed infrared spectroscopy (FTIR) analyses. The temperatures corresponding to phase transition changes were characterized by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) analyses. The crystalline structure was examined by X-ray diffraction (XRD) analysis. Additionally, the influence of pTHF–rich segment on the tensile properties, water absorption, as well as thermal and thermo-oxidative stability, has been analyzed. It was found that incorporation of soft phase allows creation of thermoplastic elastomers with tensile characteristics comparable to the commercially available ones, by means of elongation at break higher than 500%, low values of tensile modulus, without exhibiting yield point.


2010 ◽  
Vol 154-155 ◽  
pp. 230-234 ◽  
Author(s):  
Li Ping Wang ◽  
Xiao Fei Yan ◽  
Xia Xu ◽  
Ai Bin Xu ◽  
Nai Yuan Gao

A new polyferric silicate chloride(PFSC) was prepared by using sodium silicate, ferric chloride as raw materials, at the same time, its coagulation performance and the influencing factors were observed. The water containing algae was processed by PFSC coagulant and coagulation mechanism were discussed. The results showed that the best reaction time of PFSC preparation was 1h, temperature was 40°Cand Fe/Si mole ratio was 1. The removal efficiencies of chlorophyll a and turbidity were 82.40% and 94.97% respectively at 14mgFe•L-1 of dosage. Coagulation mechanism of PFSC is considered as the cooperation of oxidization/adsorption/charge-neutralization, adsorption-bridging and sweeping, which is the effect of silicic acid, iron and iron hydrolysate on the suspended particles in wastewater.


Author(s):  
Anar Kareeva ◽  
Uilesbek Besterekov ◽  
Perizat Abdurazova ◽  
Ulzhalgas Nazarbek ◽  
Irina Pochitalkina ◽  
...  

Abstract The article presents the results of studies of the process of obtaining NPK fertilizer from low-grade phosphate raw materials with P2O5 of about 18%. Phosphate raw materials were leached with a mixture of nitric-phosphoric acids with the addition of potassium carbonate, which serves as a source of potassium in the final product. The main parameters determined were the content of the main nutrients P2O5:N:K2O, temperature and time of the leaching process. According to the graphical method, the “apparent” activation energy of the heterogeneous process is found, which is equal to 3.8 kJ/mol indicates the intradiffusion nature of the process. Methods of chemical analysis, scanning electron microscopy and XRD analysis were used for a comprehensive study of raw materials and final products.


Author(s):  
Saidat Olanipekun Giwa ◽  
Maku Barbanas Haggai ◽  
Abdulwahab Giwa

In the recent time, there is increasing research in the area of alternative fuels as the exhausts of presently used petroleum-based fuels have been identified to have negative effects on the environment. Fuels produced from plant oils and animal fats have the tendencies of replacing petro fuels since they are renewable in nature. One of these renewable fuels is biodiesel. However, the homogenous catalyst used in biodiesel production has some drawbacks such as difficulty in separation from the fuel, soap formation and corrosiveness of the product mixture. In this work, the use of heterogeneous catalyst sourced from local raw materials (kaolin and eggshell) for the production of biodiesel from oil of desert date seed has been investigated. The kaolin obtained from Alkaleri Mining Site, Bauchi, was calcined in an oven at 800 °C for 3 h. The calcined kaolin was then chemically activated. Also, the eggshell-based catalyst was produced from raw eggshells after washing, drying, grinding, sieving using 0.3 mm sieve size and calcining at 900 °C for 3 h. Furthermore, the oil content of the desert date seed, which was acquired from a local market in Bauchi, was extracted via solvent extraction in a laboratory with a yield of 42%. Then, the biodiesel was subsequently prepared by mixing the oil, methanol and catalyst in a flat bottom flask and heating the mixture for a specified period. The catalyst concentration, methanol to oil ratio and time of reaction were subsequently varied to obtain the best yield. The results obtained revealed that an optimum yield of 29% could be obtained at methanol to oil ratio of 6:1 and a reaction time of 60 min using 1.5 g of eggshell-based catalyst while an optimum yield of 22% was obtained with 0.6 g for kaolin-based catalyst at a reaction time of 60 min and methanol to oil ratio of 4:1. It is recommended that further work should be carried out to improve on the yield of the biodiesel obtained using the heterogeneous catalysts.


2021 ◽  
Vol 1028 ◽  
pp. 185-190
Author(s):  
Hafizhah Ellora Della ◽  
Mochamad Zainuri ◽  
Pelangi Az Zahra ◽  
Puri Olyvia Swastika ◽  
Triwikantoro

This research study about the influence of carbon concenttration as coating on electrical conductivity of LiFeSi0.03P0.97O4/C. Synthesis of LiFeSi0.03P0.97O4/C was carried out different carbon concentrations of 7, 9, and 11 wt%. The raw materials used are Fe2O3, Li2CO3, (NH4)2HPO4, SiO2 as ion Si doping, and glucose as carbon sources. The XRD analysis results showed that all the diffraction peaks in samples were the olivine LiFePO4 phase. From the EIS result, Samples with the addition carbon concentration of 9 wt% produce the highest electrical conductivity values of 4.18 x 10-7 S/cm.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 711
Author(s):  
Benjun Cheng ◽  
Jian Xiong ◽  
Mao Li ◽  
Yuan Feng ◽  
Wenyuan Hou ◽  
...  

Despite the dominance of the blast furnace ironmaking process, more attention is being paid to the new technologies with lower energy consumption and carbon dioxide emissions. A novel flash ironmaking technology using pulverized coals and iron concentrates as raw materials, which is different from flash ironmaking with the reductive gas as the reducing agent, is studied. In order to obtain the flow patterns, temperature, and gas composition distribution, as well as particle trajectories in the reaction shaft of the flash ironmaking furnace, the Euler–Lagrangian model with a custom user defined function (UDF) code is used to simulate the processes of the fluid flow, heat and mass transfer, and chemical reactions, including the combustion reaction of pulverized coals and reduction reaction of iron concentrates. The results indicate that the flow patterns, temperature, and gas composition distributions present symmetrical distribution characteristics. The central oxygen expands rapidly after entering the reaction shaft and its distribution is approximately bell-shaped. The temperature distribution in the reaction shaft is wing-shaped. The maximum temperature, 2615 K, is reached at 5 m below the roof of the reaction shaft. The O2 is quickly consumed after entering the reaction shaft. At 6 m below the roof of the reaction shaft, the oxygen concentration becomes almost zero, with the CO concentration reaching the highest. The Fe2O3 and FeO in the iron concentrates are mostly reduced to Fe at 9 m below the roof of the reaction shaft, and more than 95 wt% iron particles could be obtained within 1.2–7.7 s.


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