DISPLACEMENT CONTROL AND KINETIC ANALYSIS OF A NOVEL VARIABLE DISPLACEMENT COMPRESSOR FOR AUTOMOTIVE AIR CONDITIONER

A novel variable displacement compressor (VDC) for automotive air conditioner (AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of pneumatic valve the displacement is controlled by electronic control valve. In order to know the control mechanism well and get a good control effect, a mathematical model for the variable displacement mechanism is developed according to the geometrical and kinematical information of the compressor. Using the model, the effect of relevant parameters on variable displace control is estimated. It is helpful to make the optimum decision in the flow control of AAC. As the novel displacement control device, the structure and control rule of electronic control valve is introduced. It can get better effect than the conventional pneumatic valves. And by using this new electronic control device, the optimum systemic control of AAC is available.

KINETIC ANALYSIS OF CO-CONDENSATION POLYMERIZATION OF AB_2 AND AB MONOMERS

This work deals with the kinetics of co-condensation polymerization of AB2 and AB monomers, giving expressions of the two-dimensional molecular weight distribution function and the number/weight average molecular weights of the resulting copolymers. The two-dimensional molecular weight distribution depends on two indices, n and l, which are the respective numbers of AB2 and AB units in a copolymer species. The evolution of the two-dimensional weight and z distributions during the co-condensation polymerization has been evaluated systematically. Finally, the two-dimensional distribution was transformed into a one-dimensional molecular weight distribution with only one variable (the molecular weight of the products instead of the degree of polymerization). The calculated results show that the highly branched copolymer has a very broad molecular weight distribution when the co-condensation polymerization approaches completion.

Kinetic analysis of soil contained pyrene oxidation by a pulsed discharge plasma process

A pulsed discharge plasma（PDP） reactor with net anode and net cathode was established for investigating the pyrene degradation in soil under different pulse peak voltage,air flow rate,pyrene content in soil,initial p H value and initial water content of the soil.Pyrene oxidation within the 60 min discharge time was fitting according to the pseudo-first order equation and the corresponding reaction kinetics constants（k values） were calculated.The obtained results show that pyrene oxidation under all the different reaction conditions obeyed the pseudo-first order equation well.Higher pulsed peak voltage and appropriate air flow rate were in favor of the increase of reaction rate of pyrene oxidation.A higher k value could be achieved in the lower initial pyrene content（the value was 100 mg kg^-1）.The k value of pyrene oxidation in the case of p H=4 was 11.2 times higher than the value obtained under the condition of p H=9,while the initial water content of the soil also has a large effect on the oxidation rate of pyrene due to the effect of PDP.

A Chemical Kinetics Perspective on the High-Temperature Oxidation of Methane and Propane through Experiments and Kinetic Analysis

In the conversion of methane and propane under high temperature and pressure,the ignition delay time(IDT)is a key parameter to consider for designing an inherently safe process.In this study,the IDT characteristics of methane and propane(700–1000 K,10–20 bar)were studied experimentally and using kinetic modeling tools at stoichiometric fuel-tooxygen ratios.All the experiments were conducted through insentropic compression.The reliable experimental data were obtained by using the adiabatic core hypothesis,which can be used to generate and validate the detailed chemical kinetics model.The IDTs of methane and propane were recorded by a rapid compression machine(RCM)and compared to the predicted values obtained by the NUIGMech 3.0 mechanism.To test the applicability of NUIGMech 3.0 under different reaction conditions,the influence of temperature in the range of 700–1000 K(and the influence of pressure in the range of 10–20 bar)on the IDT was studied.The results showed that NUIGMech 3.0 could reasonably reproduce the experimentally determined IDT under the wide range of conditions studied.The constant volume chemical kinetics model was used to reveal the effect of temperature on the elementary reaction,and the negative temperature coefficient(NTC)behavior of propane was also observed at 20 bar.The experimental data can serve as a reference for the correction and application of kinetic data,as well as provide a theoretical basis for the safe conversion of low-carbon hydrocarbon chemicals.

Quantitative kinetic analysis on oxygen reduction reaction:A perspective

Oxygen reduction reaction(ORR)constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells.However,the kinetics of ORR is very sluggish and thus highperformance ORR electrocatalysts are highly regarded.Despite recent progress on minimizing the ORR halfwave potential as the current evaluation indicator,in-depth quantitative kinetic analysis on overall ORR electrocatalytic performance remains insufficiently emphasized.In this paper,a quantitative kinetic analysis method is proposed to afford decoupled kinetic information from linear sweep voltammetry profiles on the basis of the Koutecky–Levich equation.Independent parameters regarding exchange current density,electron transfer number,and electrochemical active surface area can be respectively determined following the proposed method.This quantitative kinetic analysis method is expected to promote understanding of the electrocatalytic effect and point out further optimization direction for ORR electrocatalysis.

Biomass Carbon Improves the Adsorption Performance of Gangue-Based Ceramsites:Adsorption Kinetics and Mechanism Analysis

The large accumulation of coal gangue,a common industrial solid waste,causes severe environmental problems,and green development strategies are required to transform this waste into high-value-added products.In this study,low-cost ceramsites adsorbents were prepared from waste gangue,silt coal,and peanut shells and applied to remove the organic dye methylene blue from wastewater.We investigated the microstructure of ceramsites and the effects of the sintering atmosphere,sintering temperature,and solution pH on their adsorption performance.The ceramsites sintered at 800℃under a nitrogen atmosphere exhibited the largest three-dimensional-interconnected hierarchical porous structure among the prepared ceramsites;further,it exhibited the highest methylene blue adsorption performance,with an adsorption capacity of 0.954 mg·g^(−1),adsorption efficiency of over 95%,and adsorption equilibrium time of 1 h at a solution pH of 9.The removal efficiency remained greater than 75%after five adsorption cycles.The adsorption kinetics data were analyzed using various models,including the pseudosecond-order kinetic model and Langmuir equation,and the adsorption was attributed to electrostatic interactions between the dyes and ceramsites,n-interactions,and hydrogen bonds.The prepared coal gangue ceramsites exhibited excellent adsorption capacities,removal rates,and cyclic stabilities,demonstrating their promising application prospects for the comprehensive utilization of solid waste and for wastewater treatment.

Growth kinetics of titanium carbide coating by molten salt synthesis process on graphite sheet surface

The synthesis of carbide coatings on graphite substrates using molten salt synthesis(MSS),has garnered significant interest due to its cost-effective nature.This study investigates the reaction process and growth kinetics involved in MSS,shedding light on key aspects of the process.The involvement of Ti powder through liquid-phase mass transfer is revealed,where the diffusion distance and quantity of Ti powder play a crucial role in determining the reaction rate by influencing the C content gradient on both sides of the carbide.Furthermore,the growth kinetics of the carbide coating are predominantly governed by the diffusion behavior of C within the carbide layer,rather than the chemical reaction rate.To analyze the kinetics,the thickness of the carbide layer is measured with respect to heat treatment time and temperature,unveiling a parabolic relationship within the temperature range of 700-1300℃.The estimated activation energy for the reaction is determined to be 179283 J·mol^(-1).These findings offer valuable insights into the synthesis of carbide coatings via MSS,facilitating their optimization and enhancing our understanding of their growth mechanisms and properties for various applications.

A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been developed.The mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding stages.The simulation findings are compared to the analytical calculation results in the steady state,and both methods show good agreement.In the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model 2.Meanwhile,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting stage.The established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system operation.It is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

Kinetic analysis of γ-glutamyltransferase reaction process for measuring activity via an integration strategy at low concentrations of γ-glutamyl p-nitroaniline

At 0.12 mmol/L γ-glutamyl p-nitroaniline(GGPNA),an improved integrated method was developed for kinetic analysis of γ-glutamyltransferase(GGT) reaction process and the integration with the classical initial rate method to measure serum GGT.For the improved integrated method,an integrated rate equation,which used the predictor variable of reaction time and considered inhibitions by both GGPNA and products,was nonlinearly fit to GGT reaction processes.For the integration strategy,classical initial rates were estimated when GGPNA consumption percentages were below 50%;otherwise,maximal reaction rates of GGT were estimated by the improved integrated method and converted into initial rates according to the differential rate equation at 0.11 mmol/L GGPNA.The inte-gration strategy was validated using optimized GGT kinetic parameters and 10-s intervals to record reaction curves within 8.0 min.By the integration strategy,there was a linear response from 0.9 to 32.0 U/L GGT,coefficients of variation were below 3.5%for GGT from 8.0 to 32.0 U/L(n=5) ,and GGT activities in clinical sera responded linearly to their classical initial rates at 2.00 mmol/L GGPNA with an expected slope.Therefore,the integration strategy was successful in measuring GGT at 0.12 mmol/L GGPNA.

Co-Pyrolysis Characteristics and Kinetic Analysis of Oil Sludge with Different Additives

The addition of effective additives can effectively improve the pyrolysis performance of oil sludge(OS)and have a great potential to reduce pyrolysis costs.In the present study,co-pyrolysis performance of OS with different proportions of additives at a heating rate of 10°C/min was conducted in a thermal analyzer.Walnut shell,Fe_(2)O_(3),K_(2)CO_(3),PVC and the pyrolysis char produced from OS at the final pyrolysis temperature of 700℃were selected as the additives.TG results showed that the OS pyrolysis with and without additives can be divided into five reaction stages,which include volatilization of free water,the escape of light components,the cleavage of heavy components,carbon decomposition and inorganic minerals decomposition.The addition of additives decreased the maximum weight loss rate when the blending ratio was 5 wt%during OS pyrolysis.Kinetic analysis revealed that the overall activation energy of pyrolysis reaction was lower during pyrolysis of OS with the addition of walnut shells and pyrolysis char.The activation energy of three main reaction stages all decreased during co-pyrolysis of OS with K_(2)CO_(3)and PVC.

Chemical looping gasification characteristics and kinetic analysis of Chlorella and its organic components

Chemical looping gasification(CLG)characteristics and kinetic analysis of Chlorella(CHL),simulated Chlorella(V-CHL)and medium-chain triglycerides(MCT)were investigated using a thermogravimetric analyzer coupled with an online mass spectrometer.The apparent activation energy was obtained via Kissinger-Akahira-Sunose(KAS)method.In the result of the weightless behavior,the addition of oxygen carrier inhibited the decomposition of V-CHL at lower temperatures but promoted its decomposition at high temperatures.The values of chemical looping process characteristic parameters showed that a 10 wt%oxygen carrier would maximize the release of volatile products in the CLG of MCT,with 5.12×10^(-6)%⋅min^(-1)⋅℃^(-3).Oxygen carriers also affected gaseous products.The LHV of gaseous products of CHL reached the largest when the oxygen carrier was 10 wt%,which was 8.13 MJ/m^(3).And the gaseous product of MCT had the largest LHV with 30 wt%oxygen carrier,which was 8.83 MJ/m^(3).According to the kinetic analysis,the minimum value of apparent activation energy of MCT chemical looping gasification was 89.54 kJ⋅mol^(-1) with the oxygen carrier of 30 wt%,which was 50%less than that of MCT pyrolysis.And the minimum value for V-CHL was obtained when the mass fraction of Fe2O3 was 50 wt%.This paper could provide a reference for the choice of algae,the design of reactors,and the targeted regulation of the gaseous product for the algae CLG process.

Kinetic-spectrophotometric determination of free cyanide by stopped-flow reversed flow injection analysis

A stopped-flow reversed flow injection method for the determination of free cyanide is proposed. Pyridine-barbituric acid mixture is injected in the flow system as reagent to form the colour species with cyanide. The flow is stopped when the reagent zone comes in the flow cell, where absorbance-time data are collected at 580nm wavelength. The linear range of the determination is 0.1 -10μg/ml CN-. The sampling rate is 60h-1 and the relative standard deviation is 1.6% (n=16) at 5.0 μg/ml CN-1 level. With satisfactory results, the proposed method was applied to the determination of free cyanide in wastewater without sample pretreatment.

Efficient Gait Analysis Using Deep Learning Techniques

Human Activity Recognition(HAR)has always been a difficult task to tackle.It is mainly used in security surveillance,human-computer interaction,and health care as an assistive or diagnostic technology in combination with other technologies such as the Internet of Things(IoT).Human Activity Recognition data can be recorded with the help of sensors,images,or smartphones.Recognizing daily routine-based human activities such as walking,standing,sitting,etc.,could be a difficult statistical task to classify into categories and hence 2-dimensional Convolutional Neural Network(2D CNN)MODEL,Long Short Term Memory(LSTM)Model,Bidirectional long short-term memory(Bi-LSTM)are used for the classification.It has been demonstrated that recognizing the daily routine-based on human activities can be extremely accurate,with almost all activities accurately getting recognized over 90%of the time.Furthermore,because all the examples are generated from only 20 s of data,these actions can be recognised fast.Apart from classification,the work extended to verify and investigate the need for wearable sensing devices in individually walking patients with Cerebral Palsy(CP)for the evaluation of chosen Spatio-temporal features based on 3D foot trajectory.Case-control research was conducted with 35 persons with CP ranging in weight from 25 to 65 kg.Optical Motion Capture(OMC)equipment was used as the referral method to assess the functionality and quality of the foot-worn device.The average accuracy±precision for stride length,cadence,and step length was 3.5±4.3,4.1±3.8,and 0.6±2.7 cm respectively.For cadence,stride length,swing,and step length,people with CP had considerably high inter-stride variables.Foot-worn sensing devices made it easier to examine Gait Spatio-temporal data even without a laboratory set up with high accuracy and precision about gait abnormalities in people who have CP during linear walking.

Inhibition of acetylcholinesterase by two genistein derivatives:kinetic analysis,molecular docking and molecular dynamics simulation

In this study two genistein derivatives(G1 and G2)are reported as inhibitors of acetylcholinesterase(AChE)and butyrylcholinesterase(BuChE),and differences in the inhibition of AChE are described.Although they differ in structure by a single methyl group,the inhibitory effect of G1(IC50¼264 nmol/L)on AChE was 80 times stronger than that of G2(IC50¼21,210 nmol/L).Enzyme-kinetic analysis,molecular docking and molecular dynamics(MD)simulations were conducted to better understand the molecular basis for this difference.The results obtained by kinetic analysis demonstrated that G1 can interact with both the catalytic active site and peripheral anionic site of AChE.The predicted binding free energies of two complexes calculated by the molecular mechanics/generalized born surface area(MM/GBSA)method were consistent with the experimental data.The analysis of the individual energy terms suggested that a difference between the net electrostatic contributions(ΔEele+ΔGGB)was responsible for the binding affinities of these two inhibitors.Additionally,analysis of the molecular mechanics and MM/GBSA free energy decomposition revealed that the difference between G1 and G2 originated from interactions with Tyr124,Glu292,Val294 and Phe338 of AChE.In conclusion,the results reveal significant differences at the molecular level in the mechanism of inhibition of AChE by these structurally related compounds.

Kinetic analysis and bacterium metabolization of α-pinene by a novel identified Pseudomonas sp.strain

Biodegradation has become a popular alternative remediation technology for its economic and ecological advantages. An aerobic bacterium （strain ZW） capable of degrading α-pinene was isolated from a biofilter by a selective enrichment. Based on the 16S rRNA gene analysis and physiochemical properties, this strain was identified as Pseudomonas veronii. Under the optimized condition achieved by the response surface methodology （RSM）, as well as pH 6.82, temperature 26.3℃ and NaC1 concentration 1.36%, almost 100% α-pinene could be removed within 45 hr. Enzymatic biodegradation by the crude intracellular enzyme could be described well by the Michaelis-Menten model in which the maximum degradation rate Vraax and the half-saturation constant Km were calculated to be 0.431 mmol/（L.min） and 0.169 mmol/L, respectively. Activity assay of catechol suggested that the strain ZW possessed a catechol- 1,2-dioxygenase and could decompose benzene-ring through ortho ring cleavage. Based on the identified intermediates by GC/MS, a new metabolic pathway was proposed, in which the final metabolites were some simpler organic and inorganic compounds. The present work demonstrated that the strain ZW would have a great application prospect for the remediation of α-pinene-contaminated environment.

Isoconversional kinetic analysis of decomposition of bastnaesite concentrates with calcium hydroxide

Isoconversional methods combined with thermogravimetry were applied to investigate the decomposition kinetics of bastnaesite concentrates with different amounts of calcium hydroxide added.The apparent activation energy was calculated,and the results indicate that the overall reaction involves more than one single step.The reaction with a lower content(<15 wt%)of calcium hydroxide can be divided into two steps,while the reaction with a higher content(>15 wt%)involves another step which denotes the decomposition of newly formed calcium carbonate during roasting.The activation energy increases with increasing amount of calcium hydroxide in the lower range(0-15 wt%).This is due to the resistance of calcium hydroxide to heat and mass transport,However,more calcium can promote the decomposition reaction more effectively and thus reduce the activation energy.Nonlinear fitting was performed by fitting the experimental data to Avrami-Erofeev model to determine the reaction model and pre-exponential factor.The theoretical models were proven to be reliable for kinetic prediction.

Effect of trace calcium on melting behavior of Ag-Cu-Zn brazing alloy by thermal analysis kinetics

The purity of the brazing alloys applied is necessary to be improved with the increasing cleanness of steel. Calcium is easily brought into the widely ased brazing alloy, Ag-Cu-Zn, during the producing process. This paper aims at revealing the effect of calcium on the melting behavior of the brazing alloy. The thermal analysis kinetics of silver alloy with trace calcium was studied by using differential scanning calorimetry （ DSC ） , and the enthalpy peaks were analyzed by differential methods. The rate constant of phase transformation in the probable brazing temperature range goes up with increasing calcium content, according to the values of the apparent activation energy, E, and the frequeney constant, A. It is concluded that the calcium addition could improve the melting performance of Ag-Cu-Zn brazing alloy.

Kinetics Analysis for the Parallel Reaction of Binary Rare Earth with Tribromoarsenazo

The overall reaction was determined on the basis of the dissociation constant of TBA and the ratio of the ligand to the rare earth ion in the complex.The rate law,rate constants and acitivition energies for the reaction of La^(3+),Gd^(3+)and Ho^(3+)with TBA were studied.It is shown in the study that prerequisites for performing differential rate analysis for binary rare earths with TBA are that the pseudo-first-order parallel reaction mechanism should be conformed with,no multinuclear complex would be formed and the co-coloration effects could be neglected.

Study on Differential Rate Kinetics Analysis Based on the Substitution Reaction of Rare Earth-PHA with CyDTA

The kinetic behaviours of the substitution reaction of rare earth-PHA with CyDTA were studied systemati- cally.The relationship between the rate constant and atomic number was discussed.The rate differentiation val- ue R_d(R_d=lgk_(z+n)-lgk_z)was proposed to evaluate the possibility of differential kinetic analysis.The R_d value between the neighbouring lanthanide ions first increases and then decreases along with increasing atomic number, so that the middle and heavy rare earth mixture(such as Sm-Gd and Gd-Y)are ideal systems for the differential rate kinetic analysis.

MOF-derived porous graphitic carbon with optimized plateau capacity and rate capability for high performance lithium-ion capacitors

The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl solu-tion.The as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion storage.Additionally,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).