Reaction Speed Research Articles

Polyaniline-Supported Tungsten-Catalyzed α-H Alkylation Reaction of Ketone with Alcohol.

α-H alkylation of carbonyls is a significant reaction in the pharmaceutical industry because it can directly form a C-C bond in an environmentally benign manner. Thus, developing a novel catalyst for this reaction is a hot and practical topic in catalysis, organic synthesis, and materials science. In this paper, we found that polyaniline-supported tungsten could catalyze the α-H alkylation reaction of ketone with alcohol generating water as the only byproduct. Polyaniline support is the key for promoting the catalytic activity of tungsten, which is relatively cheaper than the traditionally employed noble metals. The reaction occurred under mild conditions with a wide substrate scope. The substrate initial concentration was enhanced to 1 mol/L, while the reaction speed was accelerated to reduce the reaction time to only 6 h; these improvements could significantly enhance the production capacity. The advantages make this reaction practical for synthesis with industrial purposes.

Sequencing of Morpholino Antisense Oligonucleotides Using Electron Capture Dissociation Mass Spectrometry.

We report the first sequencing of morpholino antisense oligonucleotides (phosphorodiamidate morpholino oligomers, PMOs) using electron capture dissociation (ECD) mass spectrometry. In this research, we found dissociation of the backbone of 18- to 25-mer PMOs to produce d and z ions as the major ions, and 100% cleavage coverage (sequence coverage) was obtained with these ions. This is a critical contrast with beam-type collision-induced dissociation, which dominantly induces base loss, so it is difficult to obtain sequence information. The results showed that an electron beam energy (typically 15 eV) can be used universally for PMOs with different sequences, lengths, and charge states so that no detailed optimization is required for multiprecursor targeting liquid chromatography coupled with tandem mass spectrometry measurements. We also confirmed that the ECD reaction speed was compatible with the high-performance liquid chromatography time scale. Finally, we demonstrated a liquid chromatography electron capture dissociation tandem mass spectrometry workflow to survey the modification sites of the emulated PMO impurities.

Development of speed and strength abilities of students during sports games

The article highlights the influence of the method of dynamic efforts on the development of speed and strength abilities of students during sports and game activities.
 The impact of this method on the rational construction of the training process, which leads to the growth of the functional capabilities of the body of young football players and the improvement of the entire set of measures responsible for preparation for general activity, was investigated.
 According to the results of the analysis of the scientific and methodological literature, it can be stated that the method of developing speed and strength abilities of students of general secondary education institutions remains relevant and requires a modernized method of applying physical exercises using the means of sports games in physical culture lessons.
 According to research, speed-power abilities increase significantly from 8-9 years to 15-16 years.
 Sports game exercises are used in the process of physical culture and sports training and education for comprehensive improvement of motor activity in difficult conditions. To the greatest extent, it allows you to improve such qualities and abilities as dexterity, speed of reaction in combination with speed of movement, strength in combination with speed and other ethical qualities of the individual.
 Strength and speed qualities are directly manifested in the amount of motor effort per unit of time, which is provided by the integral reaction of the body, associated with the mobilization of mental qualities, motor, muscle functions and functional systems.
 At any stage of individual development of speed and strength qualities, it is necessary to observe the sequence and congruence of the exercises. The selection of exercises takes place according to the principle of dynamic correspondence.
 The proposed methodical recommendations for the use of sports games as a means of developing speed and strength qualities of middle school students will improve the level of development of physical qualities.

Improved reduction efficiency, cycling performance, and removal rate of hexavalent chromium by adding water-soluble salts.

Recently, the reaction speed and cycle performance of hexavalent chromium reduction over microsized zero-valent iron (ZVI) with an Fe0 core and iron oxide (FeOx) shell structure have been improved by activating the Fe0-core electrons through electromagnetic coupling between Fe0-core electrons and charges (hexavalent chromium in solution, double-charge layers of the ZVI/solution interface). Herein, the abovementioned electromagnetic coupling was greatly increased by adding salt (CH3COONa, NaCl, NaNO3, and Na2SO4) in the hexavalent chromium solution to increase the charge response. Adding salt greatly improved the reaction speed and cycle performance of hexavalent chromium reduction. It took 8 min to reduce hexavalent chromium with CH3COONa to below the discharge standard of wastewater in the first cycle and 20 min after reducing for 20 cycles. The best apparent rate of constant value (0.416 (min)-1) is nearly four times larger than those without salts. X-ray diffraction and X-ray photoelectron spectroscopy revealed the production of amorphous iron oxide shell with salt. The salt improves the hexavalent chromium reduction speed and cycle performance and impedes the Fe0-core-electron transfer via the produced Fe2O3, resulting in existence of an optimized salt dosage. This work aims to provide an effective route for enhancing the removal efficiency and cycle performance of heavy-metal-ion reduction via Fe0. And this work also proposes a novel viewpoint that adding salt in waste water would increase the electromagnetic coupling between the charges in solution and Fe0-core electrons which could finally activate the redox reaction.

Extension of discontinuous deformation analysis method for coupled reactive transport problems

Fluid flow and the accompanying reactant transport in fractured rock masses are key concerns for understanding the performance and safety assessments of subsurface engineering problems, particularly in waste disposal and tunneling project. Nevertheless, predicting solute transport behavior remains a great challenge due to computational sophistication and numerical instability if numerous discontinuities and chemical reaction is taken into consideration. In this study, the partial differential equation describing the reactive transport of solute is solved and coupled with the Discontinuous Deformation Analysis (DDA) method. First, the extended DDA method is validated by simulating an indoor dissolution test on the single rock fracture. Then, it is applied to establish a discrete fracture network (DFN), and be further employed to investigate the reactive transport behavior and geochemical evolution in a case of acidic mine drainage in a fractured stratum. The study analyzes the effects of stress field, reaction speed, and diffusion coefficient on the reactive transport. Numerical results indicate that the conclusions reached are consistent with current findings, combined with its prominent features in simulating the mechanical behavior of discontinuities, demonstrating that the extended method is a promising tool for the coupled hydro-mechanical-chemo analysis.

Assessment of the impact of digitalization on business development in EU countries and Ukraine

The article assesses the prospects for the development of entrepreneurial activity in the EU and Ukraine in the conditions of digitalization of the economy. A methodical approach for the analysis of the development of entrepreneurial activity in the EU countries and Ukraine in the context of the digitalization of the economy has been formed, which consists of three stages. Attention is drawn to the fact that the WDCR, NRI, GII indices combine mainly institutional, economic and technological indicators that reflect the development of regulatory and legal research base, use of ICT in business, information security. The EGDI index has a more social orientation and reflects socio-economic integration - it is designed to assess the level of development of the information society. An analysis of the dynamics of changes in entrepreneurial activity in EU countries and Ukraine in the conditions of digitalization of the economy was carried out. It was established that despite the lower level of development of digitalization in Ukraine compared to the EU countries, the development trends both in the EU as a whole and in Ukraine clearly coincide. The impact of the digital component on the development of entrepreneurial activity in EU countries and Ukraine was modeled using correlation-regression analysis. It was noted that the level of digitalization does not affect the speed of the legislative body's reaction to eliminate the deterioration of the conditions of business activity, and the establishment of index indicators only according to the adopted normative legal acts does not take into account the effectiveness of the implementation of legislative changes in the field of business activity. It was concluded that among the three variables, the e-government development index has the greatest influence on the development of entrepreneurial activity. Belgium, Croatia, Italy, Slovakia, Luxembourg, the Netherlands, and Hungary have the greatest direct relationship between the development of entrepreneurial activity, the digital government development index, and digital competitiveness.

Stroboscopic Eyewear Applied During Warm-Up Does Not Provide Additional Benefits to the Sport-Specific Reaction Speed in Highly Trained Table Tennis Athletes.

While long-term training with stroboscopic eyewear suggests performance-enhancing effects on visuomotor abilities, it remains unclear whether a short-term application, for example, during a warm-up, results in immediate performance gains. This study evaluated potential performance-enhancing effects of stroboscopic eyewear applied during warm-up on reaction speed that may provide athletes an edge in visuomotor-demanding sports. Twenty-eight international-level table tennis athletes participated in this study. Participants performed their individual 10-minute table-tennis-specific warm-up under normal visual conditions and with stroboscopic eyewear. Prior to and after the warm-up, visuomotor reaction time was assessed in a sport-specific reaction test where athletes had to return 30 table tennis balls played by a ball machine at high speed to their backhand side. Reaction time was determined as the interval between ball output and movement onset as triggered by a mechanical switch. Furthermore, the time between ball-table contact and ball-racket contact (hit time) was analyzed as an indicator of how early the athletes intercepted the ball. Reaction time significantly improved following the warm-up (P < .001, ηp2=.393). However, there was no additional benefit of the stroboscopic eyewear (P = .338, ηp2=.034). No changes after the warm-up were observed for hit time (P = .246, ηp2=.055). The results indicate that warm-up facilitated visuomotor reaction speed; however, stroboscopic eyewear did not provide additional positive effects when compared to a warm-up under normal visual conditions. While shutter glasses may be useful for training over longer periods, short-term positive effects were not supported in this study.

The Influence of Catching Ball Reaction Speed Training on the Reaction Speed of the Goal Keepers

This study aims to determine the effect of ball catching reaction speed training on goalkeepers at MI Attaraqqie Malang City students. In this study, 16 meetings were carried out for 6 weeks, and 2 meetings were made forpretest and posttest. The method used in this study is an experimental method that uses a normality test and a T test. The research was carried out at the MI Attaraqqie school and forpretest andposttest conducted on the campus of State University of Malang. The number of samples that took part in the exercise was 5 students at MI Attaraqqie Malang City by using the total population. The instrument used is by using tools whole body reaction. For analysis using the normality test and T test. The results of data analysis were obtained with a value of 0.012&gt; 0.05, , which means that the value is significant. Based on the results of the data analysis conducted, it was stated that there was a significant increase in the ball catching reaction speed exercise on the reaction speed of the goalkeeper at MI Attaraqqie Malang City students.

Insights into the Sodiation Kinetics of Si and Ge Anodes for Sodium-Ion Batteries

Group IVA elements exhibit interesting Na storage capabilities due to the success of their Li alloy analogues. However, beyond hard carbon, they remain poorly understood as anodes for sodium-ion batteries (SIBs). Here, kinetic investigations of the electrochemical sodiation of Si and Ge are conducted using liquid electrolytes and half-cell configurations. Sodiation of Ge is found to be kinetically limited rather than thermodynamically limited. Either increasing temperature or decreasing sodiation rate can facilitate easier transformations from Ge to Na-Ge phases. A critical temperature seems to exist between 50 °C and 60 °C, beyond which a higher sodiation capacity is evident. The phase transformations are analyzed using Kolmogorov–Johnson–Mehl–Avrami theory. Following a one-dimensional growth, the Ge to NaGe4 is determined to be diffusion limited whereas NaGe4 to Na1+x Ge is controlled by reaction speed. Moreover, the Arrhenius equation is employed to investigate the temperature dependence on both phase transformations, giving activation energies of ∼50 kJ·mol−1 and ∼70 kJ·mol−1, respectively. Schematic models are proposed to elucidate the sodiation mechanisms, potentially influencing sought-after advancements in cell formats and classifications. Not only does this work lay the foundation for efforts on the Ge-based anodes, but also provides analogous kinetic information to Si/Sn-based ones for SIBs.

The humic substance analogue antraquinone-2, 6-disulfonate (AQDS) enhanced zero-valent iron based autotrophic denitrification: Performances and mechanisms

Zero-valent iron based autotrophic denitrification (ZVI-AD) has attracted increasing attentions in nitrate removal due to saving organic carbon budget in wastewater treatment, but limited by the low reaction speed, poor electron transfer efficiency as well as the compaction/blocking by iron hydrolysis products. Humic substances (HS) were promising to regulate iron cycle and accelerate electron transfer by serving as electron mediators. In this study, HS analogue, antraquinone-2, 6-disulfonate (AQDS), was added to enhance ZVI-AD process. Results showed that the dosage of AQDS led to a NO3−-N removal efficiency of 83.37 ± 3.98% within 96 h, which was 32.28 ± 1.25% higher than that in ZVI-AD system. The corrosion of ZVI and microbially nitrate reduction were both improved at the presence of AQDS. The addition of AQDS enriched the functional species, including autotrophic denitrobacteria namely Thauera and Hydrogenophaga, iron redox-related species namely Ferruginibacter and HS respiration related species namely Flavobacterium. The genes napA and napB related to electron transfer, nirK and nosZ related to the accumulation of intermediate products were also enriched by the addition of AQDS. AQDS addition boosted the electrons flowing to both abiotic and biotic nitrate reduction. Nitrate removal mechanism involved in ZVI-AQDS coupled system was proposed. This study provided an alternative strategy for improving ZVI-AD by HS.

0D/2D catalyst for photocatalytic mercury removal under visible light

Photocatalytic technology has the advantages of environmental friendliness, low energy consumption, and fast reaction speed, which can be applied in the field of visible light mercury removal. High stability and narrow bandgap are fundamental factors for ideal semiconductor photocatalysts. A novel method of hydrothermal synthesis of CQDs/2D-BWO composite catalyst to improve the oxidation efficiency of elemental mercury was proposed. The morphology, physicochemical properties, and optical performance of the materials were fully characterized. The experiment of Hg oxidation efficiency under visible light showed that C2/2D-BWO exhibited a Hg removal efficiency of was as high as 86.3 % under visible light and adequate cyclic stability. The effects of SO2 and NO on Hg oxidation were also studied, and the reasons for the improved of photocatalytic activity of CQDs on 2D-BWO were analyzed based on DFT calculations. The reaction mechanism of the catalytic oxidation of Hg by C2/2D-BWO was proposed, and C2/2D-BWO was found to be an efficient and stable visible light catalyst.

Delayed and More Variable Unimanual and Bimanual Finger Tapping in Alzheimer's Disease: Associations with Biomarkers and Applications for Classification.

Despite reports of gross motor problems in mild cognitive impairment (MCI) and Alzheimer's disease (AD), fine motor function has been relatively understudied. We examined if finger tapping is affected in AD, related to AD biomarkers, and able to classify MCI or AD. Forty-seven cognitively normal, 27 amnestic MCI, and 26 AD subjects completed unimanual and bimanual computerized tapping tests. We tested 1) group differences in tapping with permutation models; 2) associations between tapping and biomarkers (PET amyloid-β, hippocampal volume, and APOEɛ4 alleles) with linear regression; and 3) the predictive value of tapping for group classification using machine learning. AD subjects had slower reaction time and larger speed variability than controls during all tapping conditions, except for dual tapping. MCI subjects performed worse than controls on reaction time and speed variability for dual and non-dominant hand tapping. Tapping speed and variability were related to hippocampal volume, but not to amyloid-β deposition or APOEɛ4 alleles. Random forest classification (overall accuracy = 70%) discriminated control and AD subjects, but poorly discriminated MCI from controls or AD. MCI and AD are linked to more variable finger tapping with slower reaction time. Associations between finger tapping and hippocampal volume, but not amyloidosis, suggest that tapping deficits are related to neuropathology that presents later during the disease. Considering that tapping performance is able to differentiate between control and AD subjects, it can offer a cost-efficient tool for augmenting existing AD biomarkers.

Pyrolysis Behavior and Kinetics of Typical Crop Straw in Henan Province at Different Heating Rates

Straw, which is characterized by its low cost, large quantity, and rich supply of biomass energy, is often converted into energy that can be utilized in industrial production through pyrolysis technology. This paper examines the pyrolysis experiments of four kinds of straw (rice, wheat, peanut, and corn) from the Henan Province of China, conducted in an air environment with varying temperature-rise rates. Based on the experimental results, an analysis was conducted on the effect of the rate of temperature rise on the degree of straw pyrolysis and the pyrolysis characteristics of each type of straw. The activation energies of the pyrolysis reactions were calculated utilizing the Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Starink methods. It was concluded that the pyrolysis process of all four types of straw could roughly be classified into three stages: dehydration and drying stage, volatile release stage, and carbonization stage. Among the four types of straw evaluated, rice straw exhibited the most favorable combustion performance, while wheat straw demonstrated the best pyrolysis effect. Increasing the heating rate resulted in a pronounced thermal hysteresis effect during the straw’s pyrolysis, as evidenced by the TG and DTG curves shifting toward higher temperatures. The reaction speed increased as the heating rate increased, and the amount of residual carbon displayed an upward trend.

The influence of proton-donor solvent on [4+2] benzannulation reaction of dienal with tertiary enaminone

The [4+2] benzannulation synthesis of benzaldehyde derivative containing an electron withdrawing group at the C3 position by using the dienal and tertiary enaminone is the practical method recently, which can only be carried out in protic organic solvent. Here, the quantum chemical calculation indicates that the solvent molecule plays the vital role of proton donor which can significantly decrease the activation energy and accordingly increase the reaction speed or trend. This study provides a novel understanding for the effect of solvent environment on reaction mechanism.

Pemanfaatan Bakteri Termofilik Penghasil Amilase Pada Berbagai Pati

Indonesia is a country that produces a lot of starchy materials such as cassava, sago, corn and others. Indonesia has the potential to develop an enzyme-producing industry, especially amylase. The utilization of starchy materials which so far has not been maximized and is still limited to conventional methods can be increased by enzymatic development processes. This will increase its economic value and at the same time increase state income. One of the enzymes that is currently very widely used in the food and beverage industry is amylase. Nin Suharti and Geminsyah Putra 2021 have succeeded in isolating and identifying thermophilic bacteria from the sidedust hot springs of North Sumatra. The advantage of thermophilic bacteria is that they can produce enzymes that are resistant to high temperatures / thermostable enzymes. These enzymes are able to survive and are active at high temperatures. Such properties are highly needed by enzyme-based industries. The use of enzymes that can withstand high temperatures in the field of biotechnology can reduce operating costs and increase reaction speed, this study uses various types of starch including potatoes, cassava and corn as suitable and easily available carbon sources for the production of amylase enzymes. Bacteria in the media with potato starch added can produce the highest amylase enzyme from the three treatments of 65 U/L. For bacteria added with corn starch, the result was 50 U/L of amylase enzyme. Meanwhile, the lowest of the three treatments was media with added sweet potato starch with a content of 39 U/L. The isolates generally had a round shape, jagged edges, grooved, and smooth, white colonies, microscopic bacilli-shaped, endospores and motile, positive for catalase, gelatin and citrate tests. With Gram staining, it generally shows a positive Gram reaction.

The utilization of glycerol and xylitol in bio-based vitrimer-like elastomer: Toward more environmentally friendly recyclable and thermally healable crosslinked rubber

Eco-friendly rubbers developed from renewable materials and using covalent adaptive networks (CANs) are a family of sustainable materials that has recently attracted enormous interest from both industry and academia. In this study, vitrimer-like elastomers based on epoxidized natural rubber (ENR) were synthesized by cross-linking with dimer fatty acid (DFA). The addition of a small amount of bio-based polyol, namely the sugar alcohol glycerol (GLY) or xylitol (XYL), into the elastomeric vitrimer significantly enhanced its physical and viscoelastic properties. The glycerol-containing vitrimer tended to have reduced maximum torque, modulus, and crosslink density, while the opposite trend was found when xylitol was loaded in ENR50 vitrimer. Therefore, the mechanical and thermal properties of ENR50 vitrimer, as well as H-bond formation, can be manipulated by incorporating different types and concentrations of bio-based polyols. Importantly, a β-hydroxy ester formed in ENR50 can undergo an exchange reaction between the ester and hydroxyl group, a so-called dynamic exchange transesterification reaction, enabling thermo-healing and recycling. The formation of a denser network in polyol-treated ENR50 vitrimer may suppress the mobility of chain segments, affecting speeds of exchange reaction and stress relaxation. The ENR50 vitrimer with sugar alcohols shows several remarkable features in its mechanical performance and dynamic properties and points to an alternative for achieving green production, circular economy, and environmentally friendly processes.

Pengaruh Profesional Guru Dalam Penggunaan Media Video Interaktif Terhadap Motivasi Belajar Dan Aktivitas Belajar di SMP

The problem in this research is whether there is an influence of training methods and the use of video media together on the reaction speed of teenage volleyball athletes in Class 1) bottom serve, 2) bottom pass, 3) top pass. Variable stalk muscle. Causal quantitative research design. The method for determining the area is purposive sampling area. Population research techniques population research. Data collection techniques: 1) Observation, 2) Interview, 3) Documentary, 4) Questionnaire, 5) Test. Data analysis 1) Instrument test, 2) Classic assumption test, 3) hypothesis test. The results of the t test on reaction speed (0.737&gt;0.682), the t test of the use of video media on reaction speed (0.855&gt;0.682), the results of the F test of t test of training methods and the use of video media on reaction speed (11.384&gt;2.87). So it can be concluded that the training method and video media influence reaction speed so that H0 is rejected.

Pengaruh Metode Latihan dan Penggunaan Media Video Terhadap Kecepatan Reaksi Atlet Bola Voli

The problem in this research is whether there is an influence of training methods and the use of video media together on the reaction speed of teenage volleyball athletes in Class 1) serve under, 2) pass under, 3) pass over. Variable stalk muscle. Causal quantitative research design. The method of determining the purposive sampling area. Population research technique population research. Data collection techniques: 1). observation, 2). interview, 3). document, 4) questionnaire, 5). test. Data analysis 1) instrument test, 2) classic assumption test, 3) hypothesis test. The results of the t test on reaction speed (0.737&gt;0.682), the t test of the use of video media on reaction speed (0.855&gt;0.682), the results of the F test of t test of training methods and the use of video media on reaction speed (11.384&gt;2.87). So it can be concluded that the training method and video media have an effect on reaction speed so that H0 is rejected.

Problematic aspects of conducting an examination of drivers for the state of intoxication in health care institutions and processing it’s results

The implementation of the course for the integration of Ukraine into the European Union resulted in the need to bring national legislation into compliance with European standards. Today, the problem of effectively detecting and recording cases of drivers operating vehicles under the influence of alcohol, drugs, or other intoxicating substances, which can impair attention and reaction speed, remains highly relevant.` It is emphasized that driving vehicles while intoxicated is one of the most dangerous administrative offenses, often resulting in irreparable consequences. The article is devoted to exploring the problematic issues concerning the legal regulation of medical examinations in cases of administrative offenses in Ukraine. Amendments are proposed to the Instruction on the procedure for detecting signs of alcohol, drug, or other intoxication in drivers of vehicles, or those under the influence of drugs that reduce attention and reaction speed. This Instruction was approved by the order of the Ministry of Internal Affairs of Ukraine, the Ministry of Health of Ukraine dated November 9, 2015, No. 1452/735. The rationale is substantiated for extending the time allowed for the examination of drivers of vehicles who need to be assessed in healthcare institutions to ascertain their state regarding alcohol, drug, or other intoxication, as well as proposing changes and additions to clause 9 of Section II - ‘Conducting an examination of the state of alcohol intoxication by a police officer and registration of its results’ of the Instructions. The article highlights the issue of inadequate legislative regulation of the procedure for recording the results of the examination, laboratory tests, and diagnosis, particularly concerning the registration of medical examination results to detect the presence of driver intoxication.

Enhanced conversion of non-edible Jatropha oil to biodiesel utilizing highly reusable Mg decorated CoFe2O4 nanocatalyst: Optimization by RSM

This paper aims to develop a novel and efficient magnetic nanocatalyst for producing biodiesel from Jatropha oil. Therefore, Mg@CoFe2O4 nanocomposite as a retrievable, and strong catalyst was synthesized and employed for transesterification of Jatropha oil. After that, various analyzes were employed for characterizing Mg@CoFe2O4 nanocomposite, including XRD, Raman, FTIR, FESEM, EDX, CO2/TPD, BET, VSM, and TEM. These analyzes confirmed that Mg was successfully decorated on CoFe2O4. Response surface methodology (RSM) was employed to optimize efficient variables on biodiesel generation. The utmost biodiesel efficiency utilizing CoFe2O4 and Mg@CoFe2O4 nanocatalysts were 93.99 % and 95.49 %, respectively, which are obtained at ultrasonication time of 32.21 and 33.96 min, respectively. These biodiesel yields indicate the extraordinary efficiency of both nanocatalysts. Also, Mg@CoFe2O4 indicated a high biodiesel yield (i.e., 87.43 %) after seven reuse steps, indicating the remarkable reusability of this nanocatalyst. The thermodynamics and kinetics of transesterification showed that the biodiesel generation reaction is endothermic and the reaction speed enhanced with enhancing temperature. Moreover, decoration of CoFe2O4 with Mg led to improved catalytic performance and boosted biodiesel yield. Overall, the Mg@CoFe2O4 nanocatalyst is strongly recommended for future investigation owing to its excellent biodiesel performance, short reaction time, and extraordinary reusability of the catalyst.