Length Of Reaction Time Research Articles

The effects of reaction time on kinematic viscosity and conversion in the manufacturing of bio-ubricant alternatives from oleic acid with palm kernel shell catalyst as an approach to renewable energy

The effects of reaction time on kinematic viscosity and conversion in the manufacturing of bio-ubricant alternatives from oleic acid with palm kernel shell catalyst as an approach to renewable energy

Sintesis Nanopartikel Tembaga dari Larutan CuSO4.5H2O dengan Menggunakan Ekstrak Getah Merkubung ( Macarangan Gigantea)

The synthesis of copper nanoparticles in this study used a reducing agent from the extract of mercurd gum with a solution of CuSO4.5H20. The results of the synthesis of copper nanoparticles using the extract of mercurd gum resulted in the color of the solution becoming clear greenish. The reaction time greatly affects the formation of copper nanoparticles, it can be seen visually that after 5 minutes the reaction shows a color change from clear to clear greenish and a lot of precipitate is formed. As the reaction time increases, the solution gets darker. The color of the copper nanoparticle solution tends to be clear to clear greenish, the clear color will continue to increase with the length of reaction time. In XRD analysis of Cu which has been synthesized from 0.01 M mercury extract solution. It can be seen that Cu nanocrystals have been formed which are indicated by the appearance of peaks at 2q : 18.76˚, 22.24˚, and 23.99, The results of the Scanning Electron Microscopy analysis, the results of the SEM analysis in the study show that the particle sizes produced are different from one another and the distribution of particles is uneven, there are many particles that accumulate into chunks larger than other particles so that the size is not uniform and to form agglomerations. This is because the particle growth is very fast and UV-vis Confirmation of the formation of nanoparticles can be known through UV-Vis spectrophotometer observations by measuring the absorbance value in time intervals.

The length of reaction time on the synthesis of poly (3,4-ethylenedioxythiophene)

Poly(3,4-ethylene dioxythiophene) (PEDOT) has been synthesised via the oxidative polymerisation method of 3,4-ethylenedioxythiophene (EDOT) monomer using Na2S2O8 and Fe2(SO4)3 as oxidising agents. The synthesis was carried out at various times of reaction, i.e for 6, 12, and 24 hours. The success of PEDOT synthesis was proven by FTIR spectra which indicated by the loss of the C-H group presented in the 890 cm−1 absorption area from EDOT monomer. The morphology of PEDOT particles was observed by Scanning Electron Microscopy (SEM). The results showed that the differences in the synthesis time of 6, 12, and 24 hours affected the diameter of PEDOT particles. The size morphology of those 6, 12, and 24 hours synthetically PEDOT particles were 38.64 ± 18.21 nm, 55.91 ± 15.31 nm, and 66.62 ± 18.92, respectively. The largest diameter product of PEDOT in this study was then doped with carrageenan to synthesis PEDOT/Carr dispersions via the post-polymerisation method. This study concluded that the size of PEDOT particles is significant with increasing time of reaction, and the product of PEDOT/Carr dispersions is promising as a green polymer.

Biogasoline production via catalytic cracking process using zeolite and zeolite catalyst modified with metals: a review

Biogasoline as an alternative fuel from vegetable oil is increasingly being studied by universities, research institutions, governments and others. The fact that the low yield of biogasoline is produced, the length of reaction time, how much energy is needed during the reaction, the high reaction temperature and expensive operating costs is a challenge in the scientific world to improve and develop further research. An appropriate process technology is needed in order to produce biogasoline fuel which is equivalent to the results of petroleum fractionation. Catalytic cracking process is one of the processes that are widely studied to produce biogasoline. Along with the development of biogasoline production, the use of catalysts in the cracking process has become increasingly diverse. It is in this paper that various biogasoline production with cracking processes using catalysts focused on zeolite and zeolite catalysts modified with metals will be reviewed, including an overview of cracking raw materials, types and characteristics of zeolite catalysts, operating conditions, and how the performance of each catalyst. Zeolite catalyst which is a heterogeneous catalyst is considered to have a good ability in selectivity, activity, and ease of modification so it is very influential on cracking results. Some zeolite catalysts modified with metals such as Zn/Zeolite, Au/HZSM-5, Ni-Mo/zeolite, Pd/HZSM-5, Pt/HZSM-5 are reported to be able to provide good performance to increase biogasoline yield and certainly become a useful new catalyst in the scientific world.

Operation Conditions In Syntesize of Bioaditive From Glycerol as By-product Biodiesel : A Review

Triacetin is a good bioaditive as anti knocking agent and give increasing performance biodiesel machine. The variables studied process for syntesize of bioaditive are reaction time length, the mole ratio between glycerol and acetic acid, and the reaction temperature. Besides, in the process also much studied the effect of various catalysts to the conversion and the results obtained. . The effect of triacetin can increase motor octane number (MON) and research Octane number (RON), decrease cetane number (CN) and give better biodiesel performance.

DETERMINATION OF ANTIOXIDANT CAPACITY OF SELECTED BOROXINES

Our previous in vitro and in vivo studies on standard tumor cell lines: mammary adenocarcinoma 4T1, melanoma B16F10, and squamous cell carcinoma SCCVII have demonstrated that dipotassium-trioxohydroxytetrafluorotriborate, K2[B3O3F4OH], affects the growth of cancer cells. Based on indicative results of its anticancer activity, that are comparable to the standard cytostatic 5-fluorouracil, we decided to analyze the antioxidant capacity of K2[B3O3F4OH]. In our research, we include two other simpler representatives of the boroxine family compounds: trimethoxyboroxine and trimethylboroxine, which are commercially available. The study objective is to explore the possibility of similar behavior within the same class of boron compounds, that is, to examine the activity of K2[B3O3F4OH] compared to simpler representatives of the same family of compounds. On the one hand, K2[B3O3F4OH], theoretically has the ability to exchange electrons in the extinction of reactive radicals, since two boron atoms are sp3-hybridized and use electrons from the inner shell. On the other hand, trimethoxyboroxine, and trimethylboroxine, in theory, should not exchange electrons. However, recent studies indicate the potential for the boron atom to act like carbon and participate in the exchange of protons. The study used the standard laboratory method of 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant assay. The selected boroxines were treated with a DPPH radical at a temperature of 35° C in various concentrations, and with a reaction time of one hour. Results of the DPPH test show an extremely weak antioxidant capacity exists for all investigated boroxines. When K2[B3O3F4OH] was tested at high concentrations, instead of decreased color in the DPPH radicals, there was an increase in absorbance readings, which could mean that this compound acts as a pro-oxidant at higher concentrations. Future research is recommended to examine the length of reaction times needed, and whether a change in the reaction conditions would boost the antioxidant capacity of K2[B3O3F4OH]. Finally, future research could test the hypothesis that K2[B3O3F4OH], in the absence of the expected antioxidant activity, acts as a pro-oxidant.

Effect of Post-Synthesis Treatments on the Properties of ZnS Nanoparticles: An Experimental and Computational Study

This work deals with the characterization of ZnS NanoParticles (NP), prepared by precipitation employing thioacetamide as sulfur source at different reaction time length. The attention is focused on the modification induced on structural, surface and electronic properties of ZnS NP by post-synthesis treatments. These were aimed at removing from the samples surface adsorbed reactants, by washing or thermal treatments, both in air or vacuum. The effect of these parameters is followed by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform InfraRed (FTIR), gas-volumetric and ThermoGravimetric Analysis (TGA). Moreover, the effect of nanostructuration on the semiconducting material band gap is evaluated by Diffuse Reflectance UV-Vis (DR UV-Vis) spectroscopy. Density Functional Theory (DFT) calculations have been employed to clarify the role of the adsorbed reactants on the surface stability and to assess the relationship between particle size and band gap value.

Gas sensing property of novel flower-like nanostructure CuO

Here we report a simple hydrothermal route for the preparation of CuO nano-flower which has been proved to exhibit good performances in gas-sensing. We concentrate on the microstructure and morphology of CuO by adjusting the reaction time length. Four different morphologies that formed a flower-like shape with a diameter of 1–3 µm were obtained. The CuO nanostructures were characterized in detail by means of X-ray diffraction and scanning electron microscopy and were apparently seen that they were composed of abundant aggregative nanobelts. The prepared CuO properties in gas-sensing were also measured in our experiments. In addition, a proper growth mechanism was proposed based on the results. Moreover, the CuO nano-flowers may resolve the difficulties in low-dimensional gas-sensing applications after more research having been conducted.

Glycolthermal synthesis of Bi2MoO6 nanoplates and their photocatalytic performance

Bi2MoO6 nanoplates were successfully synthesized by a glycolthermal method at 160°C for 12h. Pure orthorhombic Bi2MoO6 nanoplates were characterized by X-ray diffraction, scanning electron microscopy and UV–visible absorption spectroscopy. The effect of reaction temperature and length of reaction time on phase and morphology of the as-synthesized products was investigated. The 2.75eV energy gap was investigated by UV−visible spectroscopy and was responsible for the photocatalysis. Photocatalytic performance of the Bi2MoO6 nanoplates evaluated through the degradation of rhodamine B under Xe light irradiation was 98.20% within 120min.

Hydrothermal Synthesis of Bi2MoO6 Visible‐Light‐Driven Photocatalyst

Bismuth molybdate (Bi2MoO6) nanoplates were synthesized by the hydrothermal reaction of bismuth nitrate and sodium molybdate as starting materials at 120–180°C for 5–20 h. X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM) were used to investigate the effect of reaction temperature and length of reaction time on phase and morphologies of the as‐synthesized Bi2MoO6 samples. In this research, orthorhombic well‐crystallized Bi2MoO6 nanoplates with the presence of stretching and bending vibrations of MoO6 and BiO6 octahedrons were detected, and the Bi2MoO6 nanoplates synthesized at 180°C for 5 h exhibit the highest photocatalytic efficiency over 96% within 100 min visible‐light irradiation.

Effect of medium solvent ratios on morphologies and optical properties of α-ZnMoO4, β-ZnMoO4 and ZnMoO4·0.8H2O crystals synthesized by microwave-hydrothermal/solvothermal method

ZnMoO4 with different morphologies were successfully synthesized by microwave hydrothermal and microwave solvothermal methods, without the use of any additives. The different crystalline phases (α-ZnMoO4, β-ZnMoO4 and ZnMoO4·0.8H2O), morphologies and optical properties of the samples were studied by X-ray diffraction, electron microscopy and spectroscopy, and were found to be influenced by the length of reaction time and the different volume ratios of ethylene glycol (EG) to water as medium solvents. In this research, the direct energy gap (Eg) and photonic emission wavelength were evaluated to be 3.13–3.51eV and 366nm, respectively.

C60 reduces the bioavailability of mercury in aqueous solutions

The effects of C60 on mercury bioavailability and sorption were investigated at different C60 dosages, reaction times, and pH ranges using the merR::luxCDABE bioluminescent bioreporter Escherichia coli ARL1. The results demonstrated that the bioavailability of mercury (Hg2+) decreased with increasing C60 dosage. Approximately 30% of aqueous mercury became biologically unavailable 2h after interaction with C60 at a mass ratio of C60 to mercury as low as 0.01. However, this reduction in bioavailability plateaued at a mass ratio of C60 to mercury of 10 with a further increase in C60 concentrations resulting in only a 20% additional decrease in bioavailability. If this reduction in bioluminescence output is attributable to mercury sorption on C60, then each one log-order increase in C60 concentration resulted in a 0.86 log-order decrease in the mercury partitioning coefficient (Kd). This relationship implies the presence of high mercury-affinitive sites on C60. The length of reaction time was found to play a more important role than C60 dosage in reducing Hg2+ bioavailability, suggesting an overall slow kinetics of the C60–Hg interactions. In addition, lowering the pH from 7.2 to 5.8 decreased mercury bioavailability due likely to the increase in mercury’s association with C60. These results suggest that C60 may be useful in capturing soluble mercury and thus reducing mercury biotoxicity.

Enol Ethers as Substrates for Efficient Z- and Enantioselective Ring-Opening/Cross-Metathesis Reactions Promoted by Stereogenic-at-Mo Complexes: Utility in Chemical Synthesis and Mechanistic Attributes

The first examples of catalytic enantioselective ring-opening/cross-metathesis (EROCM) reactions that involve enol ethers are reported. Specifically, we demonstrate that catalytic EROCM of several oxa- and azabicycles, cyclobutenes and a cyclopropene with an alkyl- or aryl-substituted enol ether proceed readily in the presence of a stereogenic-at-Mo monopyrrolide-monoaryloxide. In some instances, as little as 0.15 mol % of the catalytically active alkylidene is sufficient to promote complete conversion within 10 min. The desired products are formed in up to 90% yield and >99:1 enantiomeric ratio (er) with the disubstituted enol ether generated in >90% Z selectivity. The enol ether of the enantiomerically enriched products can be easily differentiated from the terminal alkene through a number of functionalization procedures that lead to the formation of useful intermediates for chemical synthesis (e.g., efficient acid hydrolysis to afford the enantiomerically enriched carboxaldehyde). In certain cases, enantioselectivity is strongly dependent on enol ether concentration: larger equivalents of the cross partner leads to the formation of products of high enantiomeric purity (versus near racemic products with one equivalent). The length of reaction time can be critical to product enantiomeric purity; high enantioselectivity in reactions that proceed to >98% conversion in as brief a reaction time as 30 s can be nearly entirely eroded within 30 min. Mechanistic rationale that accounts for the above characteristics of the catalytic process is provided.

Synthesis of cyclic carbonates and dimethyl carbonate using CO2 as a building block catalyzed by MOF-5/KI and MOF-5/KI/K2CO3

The synthesis of cyclic carbonates or dimethyl carbonate (DMC) using CO2 as a building block is a very interesting topic. In this work, we found that the metalorganic framework-5 (MOF-5)/KI was an active and a selective catalytic system for the synthesis of cyclic carbonates from CO2 and epoxides, and MOF-5/KI/K2CO3 was efficient for the preparation of DMC from CO2, propylene, and methanol by a sequential route. The impacts of temperature, pressure, and reaction time length on the reactions were investigated, and the mechanism of the reactions is proposed on the basis of the experimental results.

An analgetic activity of sedges (Cyperus rotundus L.) extract on white male mice (Mus musculus L.)

The objectives of the research were to find out the effect of giving sedges root extract orally on the number of writhing after chemical pain induction and time reaction after thermal pain induction of mice and also to find out the extract dosage which had an influence on decreasing number of writhing after chemical pain induction and length of reaction time after thermal pain induction of mice. The Complete Random Design (CRD) with 6 treatment groups and each treatment used 5 repetitions were used in this study. The groups were: Group I , control group, treated with sedges root extract of 0 mg/ 20 g BW , 0,5 ml; Group II treated with sedges root extract of 1 mg/ 20 g BW, 0,5 ml; Group III treated with sedges root extract of 3 mg/ 20 g BW, 0,5 ml; Group IV treated with sedges root extract of 5 mg/ 20 g BW, 0,5 ml; Group V treated with sedges root extract of 7 mg/ 20 g BW, 0,5 ml; Group VI treated with asetosal 200 mg/ kg BW , 0,5 ml/ 20 g BW and for the activity test, the sedges root extract was suspended in CMC 1%. Induction of chemical pain was done according to Witkin et al. (1965) in Pudjiastuti et al. (2000), in which 0,1 ml 3% of Acetic Acid/ 20 g BB was injected intraperitoneally 30 minutes after giving oral-material test. The mouse gave a respond in the way of writhing. Thermal pain induction was done by placing the mouse on hot plate with constant temperature of 55oC. The mouse gave a respond in the way of lick its back foot or even jumping. The data collected was analyzed using one direction ANOVA model and it was continued with LSD test in order to find out the difference every treatment group. The result of the analysis showed that the sedges root extract dosage of 7 mg/ 20 g BB decreased the number of writhing after chemical pain induction and length of mouse time reaction after thermal pain induction, so that sedges root extract dosage 7 mg/ 20 g BB had an analgetic function.

Relationship between the degree of inhibited stretch reflex activities of the wrist flexor and reaction time during quick extension movements

It has been reported that stretch reflex responses, including the long latency component, are modulated by motor preparation for the direction and type of movement. In the present study, human subjects were required to make a reaction movement in the direction of the wrist extension following a muscle stretch to the wrist flexor, and we investigated the relationship between the modulation of reflex activities of the wrist flexor and the length of reaction time (premotor time) of the wrist extensor. Twenty-five healthy males, ranging in age from 20 to 28, participated in the experiments. A DC torque motor was used to evoke the reflex EMG responses on the flexor. Averaging the rectified EMG, recorded with the surface electrodes over the flexor, showed short and long latency reflexes (M1 and M2 components) in response to the muscle stretch. For all subjects, the amplitudes of the reflex components during the extension reaction movement decreased, compared to those amplitudes in the non-reaction tasks. The decrease in the M2 component, which is considered a transcortical reflex, was significantly larger than the decrease in the M1 component, which is a spinal reflex. Moreover, there were correlations between reaction time to muscle stretch and the degree of decrease in reflex activities with the extension reaction ( r=0.652 for M1, r=0.813 for M2, P<0.01). It became clear that the subjects with shorter reaction times inhibited their reflex activities of the flexor, particularly the M2 component which prevents the extension movement, to a greater degree than the subjects with longer reaction times. Therefore, our results suggest that the degree of M2 modulation directly reflects the individual motor control required to perform quick movements.

Reaction of 4-Oxochromene-3-carboxaldehydes with Primary Amides and Benzotriazole or 1H-1,2,4-Triazole

N-[(6-substituted-4-oxochromen-3-yl)(1,2,4-triazol-3-yl)methyl]amides 5 and N-[(6-substituted-4-oxochromen-3-yl)(benzotriazol-1-yl)methyl]amides 6 were prepared by the reaction of 6-substituted 4-oxochromene-3-carboxaldehydes 1 with primary amides and 1H-1,2,4-triazole or 1H-benzotriazole. 6-Substituted 3-[hydroxy(1,2,4-triazol-1-yl)methyl]chromen-4-one 2 and 6-substituted 3-[hydroxy(benzotriazol-1-yl)methyl]chromen-4-one 3 were isolated as stable intermediates of these reactions. Beneficial effect of microwave irradiation on length of reaction time was observed. Some reactions of these derivatives with O, S, and N nucleophiles are described.

CHEMICAL EVALUATION OF SOIL-SOLUTION IN ACID FOREST SOILS

Soil-solution chemistry is commonly studied in forests through the use of soil lysimeters. This approach is impractical for regional survey studies, however, because lysimeter installation and operation is expensive and time consuming. To address these problems, a new technique was developed to compare soil-solution chemistry among red spruce stands in New York, Vermont, New Hampshire, and Maine. Soil solutions were expelled by positive air pressure from soil that had been placed in a sealed cylinder. Before the air pressure was applied, a solution chemically similar to throughfall was added to the soil to bring it to approximate field capacity. After the solution sample was expelled, the soil was removed from the cylinder and chemically analyzed. The method was tested with homogenized Oa and Bs horizon soils collected from a red spruce stand in the Adirondack Mountains of New York, a red spruce stand in east-central Vermont, and a mixed hardwood stand in the Catskill Mountains of New York. Reproducibility, effects of varying the reaction time between adding throughfall and expelling soil solution (5-65 minutes) and effects of varying the chemical composition of added throughfall, were evaluated. In general, results showed that (i) the method was reproducible (coefficients of variation were generally < 15%), (ii) variations in the length of reaction-time did not affect expelled solution concentrations, and (iii) adding and expelling solution did not cause detectable changes in soil exchange chemistry. Concentrations of expelled solutions varied with the concentrations of added throughfall; the lower the CEC, the more sensitive expelled solution concentrations were to the chemical concentrations of added throughfall. Addition of a tracer (NaBr) showed that the expelled solution was a mixture of added solution and solution that preexisted in the soil. Comparisons of expelled solution concentrations with concentrations of soil solutions collected by zero-tension and tension lysimetry indicated that expelled solution concentrations were higher than those obtained with either type of lysimeter, although there was less difference with tension lysimeters than zero-tension lysimeters. The method used for collection of soil solution should be taken into consideration whenever soil solution data are being interpreted.

Interaction and mobility of cobalt-60 between water and sediments in marine environments possible effects by acid rain

In Japan, all nuclear power stations have been constructed facing sea-shores and the operating radioactive wastes have been either stored at the sites or discharged into marine environments, if permissible. The purpose of this investigation was to understand the behavior of a radioactive cobalt ( 60Co), one of the typical radionuclides produced by operating nuclear reactors, in marine environments, namely cobalt interaction between water and sediments. Great emphasis was focused on demonstrating a quantitative difference in behavior of cobalt between marine and freshwater environments. Under natural conditions, cobalt remained in the water phase in marine environments more than 5 times as much as in freshwater environments. In freshwater, most cobalt (over 95%) is absorbed by and permanently retained within bed sediments under the normal environmental conditions. However, in marine environments cobalt gains mobility. Furthermore, this mobility of cobalt once established did not diminish nor disappear when surrounding conditions were changed. In short, cobalt in marine environments is generally mobile. This considerable mobility was greatly influenced by the environmental factors: (e.g. pH, the redox potential, the ionic strength, the type of sediments and the length of reaction time) but, it was primarily determined by the initial environmental conditions. The result of this experiment suggests that the treatment and the storage of radioactive cobalt waste should be done in freshwater environments rather than in a marine environment if we try to reduce the mobility. Because the mobility depends on pH, acid rain is, therefore, to be expected to strongly influence the mobility of 60Co in aquatic environments.

Response Time as a Function of Uncertainty

The purpose of this study was to compare uncertainty among simple reaction time, compatible reaction time and disjunctive reaction time for 25 students. The results indicated variable differences in length of reaction time, i.e., simple RT &lt; compatible RT &lt; disjunctive RT. A sign test, performed for both mean and median scores, was significant. It was concluded that reaction time did increase as a function of uncertainty.