Changes In Force Research Articles

Corporate Legitimacy: A Passport to Iron Law of Responsibility Evasion in Contemporary Business Space

The environment of business in Nigeria is overly getting more complex and unpredictable than ever before. This trend is occasioned by the rapid changes in social, technological, political, legal and economic forces which thus, mount both favorable and unfavorable pressures on organizations in their quest to maintain operational stability amid competition. In the light of this circumstance, organizations in their bid to remain operationally efficient often engage in some unethical behaviors which tend to question their legitimate standing and possible invocation of iron law of responsibility by the society. Following this observation, this paper theoretically examined the linkage between corporate legitimacy and iron law of responsibility evasion in modern business space. In pursuit of this, strategic adaptation. strategic manipulation and moral reasoning were adopted as manifest properties of the predictor variable. Consequent upon extant literature exploration, it was found that the society serves as a host to all businesses, and as such has the power to select in and out any business depending on its observed corporate behavior. The paper in line with the findings, concludes that corporate legitimacy is a strategic passport through which an organization’s activities and behavior is given validity and acceptance by the society to prosper. It was however recommended that that for a business to continually escape the wrath of iron law of responsibility and secure legitimacy, managers should embrace moral reasoning option in their quest to establish legitimacy, especially as it allows the organization to peacefully bargain or negotiate with the society on issues of social concern in order bring about a match between business practices and social expectations.

The West Pacific Teleconnection Drives the Interannual Variability of Autumn Wildfire Weather in the Western United States After 2000

AbstractWildfires pose a significant threat to human society as severe natural disasters. The western United States (US) is one hotspot that has experienced dramatic influences from autumn wildfires especially after 2000, but what has caused its year‐to‐year variations remains poorly understood. By analyzing observational and atmospheric reanalysis datasets, we found that the West Pacific (WP) pattern centered in the western North Pacific acted as a major climatic factor to the post‐2000 autumn wildfire activity by inducing anomalous high pressure over the western US via teleconnections with increased surface temperature, decreased precipitation, and reduced relative humidity. The WP pattern explains about one‐third of the post‐2000 years‐to‐year variance of the western US autumn wildfires. These effects were found to be much weaker in the 1980–1990s, as the active region of WP‐associated high pressure was confined to the eastern North Pacific. Such eastward shift of the WP teleconnection pattern and its resultant, enhanced influence on the weather conditions of western US autumn wildfire after 2000 are also captured by the sea surface temperature (SST)‐forced atmospheric model simulations with the Community Atmosphere Model version 6 (CAM6). The CAM6 ensemble‐mean changes in the WP teleconnection pattern at 2000 is about half of the observed changes, which implies that external radiative forcing and/or SST changes have played an important role in the WP pattern shift. Our results highlight a pressing need to consider the joint impacts of atmospheric internal variability and externally forced climate changes when studying the interannual variations of wildfire activity.

Large-Scale Group Decision Making with Dual Feedback from Community Residents Based on the Organizational Invisible Field

In China, communities function as grassroots self-governing bodies, and the enhancement of public participation in community governance has remained a central focus of study. This paper applies the Large-Scale Group Decision-Making (LSGDM) method to the process of community self-governance and proposes a dual feedback group consensus decision-making model that takes into account the unique social relations among residents. Firstly, the concept of the Organizational Invisible Field—formed in communities by intangible social capital such as positional power and interpersonal relationships within the organization—is introduced. The definition of Invisible Field Force is utilized to measure the influence of these forms of capital on social relationships. Subsequently, drawing on field dynamic theory, the process by which residents’ preferences within the organization are shaped by the action of Invisible Field Force is explored. Secondly, acknowledging that invisible relationships can be affected by dynamic interactions during the decision-making process, the Invisible Field Force change model is constructed. Building on this, a dual feedback consensus coordination mechanism—encompassing both in-organization members and all residents—is designed. Finally, the validity and utility of the model are verified through case studies and sensitivity analyses.

Simulation and experimental study of aerodynamic characteristics of a rotor adsorption wall-climbing robot

Abstract High-rise buildings are prone to gusts of wind, especially crosswinds. In order to investigate the effect of crosswinds on the aerodynamic characteristics of rotor blades at different near-wall distances, a CFD simulation model is designed for four near-wall distances and five wind speeds, and the change curves of rotor pulling force, pressure cloud diagrams and velocity cloud diagrams are obtained by using Fluent for the various conditions. The mechanism and pattern of its influence on the aerodynamic characteristics of rotor blades are studied by observing the pulling force change curve and cloud diagram. Finally, an experimental platform is built to verify the correctness of the simulation results. The simulation and experimental results have a similar law, i.e., crosswinds do not only have a negative effect on reducing the pulling force generated by the rotor blades, but can also have a gain effect on the pulling force in some cases. This law has some application value, which can be utilized to compensate the rotor speed accordingly. When the pulling force is reduced, the speed is increased appropriately to improve the reliability of the adsorption, and when the pull force is increased, the speed is reduced appropriately, which can reduce the power consumption and increase the range.

THE IMPORTANCE OF HUMAN RESOURCES PLANNING IN STRATEGIC MANAGEMENT

Changes in competitive conditions force businesses to develop new capabilities in order to sustain their existence and be successful. At this point, businesses have made an effort to change their management approach and gain a strategic perspective. This approach, called strategic management, involves the effective use of the resources that the business has in order to regulate the relations between the business and its environment and to gain superiority over competitors or to make a difference. The most important resource that businesses have is human resources. The most important key to the adoption and successful implementation of the strategic management approach is to have an effective manpower. With a strategic human resources planning, businesses will be able to ensure that employees are provided at the right time, with the desired qualifications and assigned to the right jobs in line with the business strategy. The purpose of this study is to create a conceptual framework for the role of human resource planning in the strategic management process. At this point, the studies on strategic management, human resource management and strategic human resource management in the literature were examined in detail. As a result of the research, it was concluded that strategic human resources planning is the process of creating comprehensive and long-term human resources strategies and developing the plans, programs and tactics necessary for the implementation of these strategies, and that businesses that manage this process in the best way can establish superiority over their competitors by identifying opportunities, threats, advantages and weaknesses.

RATIONAL SHIFTS OF THE BASIC RACK’S PROFILE FOR WHEELS OF A CYLINDRICAL SPUR GEAR PAIR TO DECREASE TEETH WEAR

Purpose. It is to create a method for determination of such shift coefficients of the basic rack’s profile for driving and driven wheels of a cylindrical spur gear pair, that during gear pair operation time the wear rate of a surface layer on the most wearing sections of the teeth’ involute surfaces will be minimal. Research methods are based on integrated application of the involute gear pair theory and tribological laws. The golden section method is used to minimize the function. Results. We have obtained a dimensionless quantity, which is a function of shift coefficients of the basic rack’s profile for driving and driven wheels of a cylindrical spur gear pair. Values of this function are proportional to the greatest wear rate in the neighborhood of characteristic points on teeth’ involute profiles of these wheels. The method is created for determination of rational shift coefficients of the basic rack’s profile, which minimize the obtained dimensionless function, and which maximize the service life of the spur gear pair until the greatest worn-layer thickness on the teeth’ active surfaces reaches limiting permissible value. Scientific novelty. It is proved, that increasing of the worn-layer thickness during spur gear pair operation time will be occurring most rapidly in the neighborhood of certain characteristic points on teeth’ involute profiles of the wheels. Calculation model is elaborated for determination of the worn-layer thicknesses in the neighborhood of extreme active points on teeth’ profiles of the cylindrical spur gear pair and in the neighborhood of the lowest and the highest bounding points of single-pair contact. This model takes into account the influence of specific slides and numbers of wheels’ teeth as well as hardness values of teeth’ surface layer on the wear rates at characteristic points of teeth’ profiles. In addition, the model takes into account sharing of total force of the wheels interaction between two teeth pairs in double-pair contact and also a change of force transmitted by single pair of teeth when it comes into or go out of engagement. Practical value. Application of the created method for determination of shift coefficients of the basic rack’s profile is expedient in design of cylindrical spur gear pairs for machines and equipment, which operate in conditions when ingress of abrasive particles in the teeth engagement region is possible. An example of application of this method in design calculation of the cylindrical spur gear pair is given.

The mitochondrial-targeted peptide therapeutic elamipretide improves cardiac and skeletal muscle function during aging without detectable changes in tissue epigenetic or transcriptomic age.

Aging-related decreases in cardiac and skeletal muscle function are strongly associated with various comorbidities. Elamipretide (ELAM), a novel mitochondrial-targeted peptide, has demonstrated broad therapeutic efficacy in ameliorating disease conditions associated with mitochondrial dysfunction across both clinical and pre-clinical models. ELAM is proposed to restore mitochondrial bioenergetic function by stabilizing inner membrane structure and increasing oxidative phosphorylation coupling and efficiency. Although ELAM treatment effectively attenuates physiological declines in multiple tissues in rodent aging models, it remains unclear whether these functional improvements correlate with favorable changes in molecular biomarkers of aging. Herein, we investigated the impact of 8-week ELAM treatment on pre- and post-measures of C57BL/6J mice frailty, skeletal muscle, and cardiac muscle function, coupled with post-treatment assessments of biological age and affected molecular pathways. We found that health status, as measured by frailty index, cardiac strain, diastolic function, and skeletal muscle force are significantly diminished with age, with skeletal muscle force changing in a sex-dependent manner. Conversely, ELAM mitigated frailty accumulation and was able to partially reverse these declines, as evidenced by treatment-induced increases in cardiac strain and muscle fatigue resistance. Despite these improvements, we did not detect statistically significant changes in gene expression or DNA methylation profiles indicative of molecular reorganization or reduced biological age in most ELAM-treated groups. However, pathway analyses revealed that ELAM treatment showed pro-longevity shifts in gene expression such as upregulation of genes involved in fatty acid metabolism, mitochondrial translation and oxidative phosphorylation, and downregulation of inflammation. Together, these results indicate that ELAM treatment is effective at mitigating signs of sarcopenia and heart failure in an aging mouse model, but that these functional improvements occur independently of detectable changes in epigenetic and transcriptomic age. Thus, some age-related changes in function may be uncoupled from changes in molecular biological age.

A multi-proxy stalagmite record indicates a shift in forcing of twentieth century drought events in Normandy

Drought events are increasingly impacting Europe. The study of past droughts helps disentangle the different factors that trigger hydrological drought, helping to forecast future drought severity. Here we identify the historical drought events of the twentieth and twenty-first centuries in geochemical records of a stalagmite from Caumont cave in Northern France and develop a mechanistic understanding of their root causes. Subannually-resolved stable carbon isotope (δ13C) and trace element data are directly compared with historical climatic records. δ13C, Mg, and Sr peaks align well with most of the historical drought events of the twentieth and twenty-first centuries. The comparison reveals a good correspondence between summer effective rainfall and δ13C, Mg, and Sr concentrations. Further comparison of geochemical records with the precipitation-evapotranspiration index (SPEI) reveals a change in the drought forcings for the past two decades. During most of the twentieth century, droughts appear driven by a pluvial regime, whereas since the late 1990s, drought was driven by higher evapotranspiration due to increased temperature.

A Synoptic Scale Perspective of Solar Forcing on Extreme Precipitation and Floods Over Europe During Summer

AbstractThe relationship between total solar irradiance (TSI) forcing and summer extreme precipitation and flood frequency over western Europe is investigated from a synoptic‐scale perspective, with a focus on the role of Rossby wave packets (RWPs). Utilizing observational, model, and proxy data, we reveal a significant increase in RWP frequency along a zonal band centered around 50°N, extending from North America to western Europe, during periods of low TSI. This anomaly in RWP frequency is consistent with a significant increase in the frequency of extreme precipitation events recorded over western Europe. Sensitivity experiments conducted with a state‐of‐the‐art chemistry‐climate model corroborate our findings based on observational data. Additionally, a flood record from western Europe demonstrates a significant increase in flood frequency during low TSI years, a relationship that persists across timescales. We argue that the frequency patterns associated with TSI forcing presented in this study are robust and, therefore, valuable for estimating the frequency of extreme precipitation events over western Europe under various solar irradiance scenarios. Moreover, our findings indicate that the North Atlantic sector is more responsive to changes in solar forcing during the boreal summer than previously thought, with this effect manifesting primarily on synoptic timescales rather than the long‐term climatological mean.

Autoinjector optimization through cavitation response and severity minimization

Abrupt acceleration of the syringe of an autoinjector (AI) upon rod-plunger impact may induce undesired severe cavitation events and impose extraneous stresses upon the device, leading to device failure. Cavitation results from a rapid and significant pressure drop in a liquid, leading to the formation and growth of small vapor-filled cavities. Upon collapse, these cavities generate an intense shock wave that may lead to protein aggregation and device container damage and shatter. Since the maximum acceleration of the syringe depends upon the operating conditions of the AI, the severity of cavitation will likewise depend on the operating conditions of the AI. Likewise, injection time and ensuring proper needle displacement before drug release also depend on operating conditions, making optimization of the autoinjector a multiobjective optimization problem.Therefore, in this study, optimization of an autoinjector to limit cavitation severity is pursued via an experimentally validated computational model for cavitation in spring-driven autoinjectors. Our goal is to locate AI design configurations that balance maximizing device performance and patient comfort and minimizing the risks of device damage and severe cavitation upon actuation.Relevant parameters of interest are the drive spring force, air gap height, solution viscosity, friction between the rod and spring, frictional force on the plunger, rates of change of frictional force on the plunger, elasticity of plunger, viscosity of the plunger, and initial displacement between the plunger and the driving rod. The kinematics of the syringe barrel, needle displacement (travel distance) at the start of drug delivery, and injection time are gathered using an experimentally validated autoinjector kinematics model. At the same time, cavitation bubble dynamics are resolved using an experimentally validated cavitation model that takes the temporal displacement of the syringe and temporal air gap pressure as inputs.We use our experimentally validated models to explore the parameter space and understand the driving factors of our desired outcomes. Subsequently, we pose the design problem as a multi-objective optimization problem and develop a deep neural network surrogate model supplemented with iterative learning to speed up optimization. A variance-based sensitivity analysis was performed to determine the sensitivity and influence of design parameters on the outcomes, and the main contributors to the outcomes of interest were isolated. Using a multi-objective optimization framework, we located 300 + successful candidates and evaluated them through uncertainty analysis to identify three promising candidates that meet all criteria for drug viscosities of interest. Finally, we show that this methodology can be used to conduct hypothesis testing, leading to novel design configurations.

Internal Combustion Engine Fault Detection Based on Random Convolutional Neural Networks

The internal combustion engine plays a very important role in many fields, and when the internal combustion engine fails, if it is not found in time, it may cause continuous damage to the internal combustion engine, and further affect the life of the entire mechanical system. To solve the above problems, this paper proposes fault detection of internal combustion engines based on a random convolutional neural network. The cylinder burst noise signal of the internal combustion engine is decomposed by a stationary wavelet, and the inclusion matrix is composed of partial decomposition coefficients. Using singular value theory, the singular value containing matrix is extracted as the characteristic of cylinder burst noise signal. The singular value is used as the input of a random convolutional neural network to train and identify faults. The AdaBound optimizer was then applied to adapt the learning rate to changes, thereby accelerating the weight update of the model. At the same time, the neurons in the structure are randomly deactivated by dropout technology to prevent complex collaborative responses to the training data, and the diagnosis results of each network model are integrated by Dempster synthesis rules. The experimental results show that the minimum mean square error of 0.00165 is achieved when there are 15 neurons in the hidden layer, and it gradually increases as the number of neurons increases. Therefore, it is determined that there should be 15 neurons in the hidden layer, and the trainLM algorithm is used. The decision factors for training, validation, cross-validation, and overall data are 0.98947, 0.98597, 0.97738, and 0.9801, respectively, all reaching the control accuracy of 0.95, which indicates that the random convolutional neural network proposed has a high accuracy for internal combustion engine fault detection. For the main bearing Y-directional force, as the gap increases, its fluctuation trend strengthens; the main bearing force changes within a small range at first, then increases sharply when the gap reaches 0.2[Formula: see text]mm, and some main bearings even experience significant impact loads.

Identification of genetic variants associated with exercise-induced atrial fibrillation in high-performing racehorses

Abstract Background Atrial fibrillation (AF) is the most common cardiac arrhythmia in athletes. Despite a lower burden of classical cardiovascular risk factors, the prevalence of AF in athletes is comparable to that in the general population of similar age (~13%, mean age 65.5), suggesting that exercise-induced AF may have different underlying mechanisms. The prevalence of AF in thoroughbred (TB) and standardbred (STB) racehorses is also relatively high (~5%), suggesting exercise as an independent risk factor. Due to selective breeding and complete control of pedigrees, racehorses are well-suited for genetic studies. Common and rare genetic variation explain a substantial part of AF variance, but no study has identified genetic variants associated with exercise-induced AF in any species. Objective In this project, we aimed to use the racehorse as a model to identify genetic variants associated with exercise-induced AF, and in a future study, possibly replicate the results in human athletes. Here we present preliminary results from the genome-wide association study (GWAS) of AF in racehorses. Methods We collected blood or hair samples from 181 STB and TB racehorses in which 71 had paroxysmal or persistent AF verified by ECG. We extracted DNA and performed whole-genome genotyping using a commercial equine genotyping platform (670k markers). We phased and imputed un-genotyped markers and increased the sample size of the control group, using publicly available equine data from similar breeds from the European Nucleotide Archive. We conducted a GWAS of 7.85 million markers in 71 cases and 296 controls using PLINK2 with covariates adjusted for population stratification, batch and sex. Results We identified one significant locus downstream of the protocadherin gene PCDH18 associated with AF in racehorses. The same locus has been associated with the ECG-trait P-wave terminal force in humans. Changes in P-wave terminal force is associated with increased atrial size, delayed interatrial conduction, left ventricular fibrosis and left atrial function, and considered a good predictor of AF occurrence. Several non-significant but interesting signals were also identified including the genes SLC6A15 (amino acid transport), MYBPH (myosin binding), MYF6 and MYOG (myoblast differentiation). Conclusion In these preliminary results, we have identified a new genetic locus associated with AF in racehorses. In addition, we have identified several candidate genes for further studies to elucidate the genetic background of exercise-induced AF. We aim to replicate our findings in a population of human athletes. Our results may aid the development of risk prediction tools for exercise-induced AF and new drugs for tailored treatment of AF in general.

A Normal Displacement Model and Compensation Method of Polishing Tool for Precision CNC Polishing of Aspheric Surface.

The position accuracy of the polishing tool affects the surface quality of the polished aspheric surface. The contact deformation among the polishing tool, abrasives, and aspheric part can cause a displacement, which, in turn, will cause a position error of the polishing tool, which will lead to a significant change in the polishing force. In order to resolve this error, this paper proposed a method of normal displacement compensation for a computer numerical controlled (CNC) polishing system by controlling the polishing force. Firstly, the coupling principle between the polishing force and the position of the polishing tool is expounded, and the relationship between normal displacement and deformation is analyzed. Based on Hertz's theory, a model of normal displacement is established. Then, on the basis of the decoupled polishing system developed, a normal displacement compensation method was proposed. Finally, a group of comparative experiments was carried out to verify the effectiveness of the proposed method. Compared with no displacement compensation, when the part was polished with the normal displacement compensation method, the value of roughness decreased from 0.4 µm to 0.21 µm, and the unevenness coefficient of surface roughness decreased from 112.5% to 19%. The experimental results show that the polishing quality is improved greatly, and the aspheric surfaces can be polished more uniformly with the method proposed in this paper.

Enhanced eddy activity along the Subantarctic Front under intensified westerly winds

The westerlies in the southern hemisphere have intensified and shifted southward since the middle of the twentieth century. Previous studies have indicated that the expected increase in isopycnal slopes and acceleration of the Antarctic Circumpolar Current (ACC) is considerably weakened by the strengthening of mesoscale eddies and that this “eddy saturation” occurs mainly downstream of the major bottom topographic features such as the Kerguelen Plateau. Such eddy “hotspots” are thus considered to regulate the ACC responses to changes in external forcing. To improve our understanding of the ACC response to intensified winds, a sensitivity study is conducted using an eddy-resolving quasi-global ocean general circulation model named “OFES.” The reference run is driven by a climatological atmospheric forcing and the sensitivity run is driven by artificially intensified climatological westerlies. Our new finding is that the baroclinic energy pathway is enhanced over the Subantarctic Front (SAF) as well as over the hotspots identified by previous studies. A linear stability analysis indicates that the spin-up of the subtropical gyres north of the SAF and the enhanced Ekman upwelling south of the SAF by the intensified wind stress curl increase the vertical shear of zonal velocity along the SAF, enhancing baroclinic instability. We have also performed the same stability analysis comparing the 1985–2018 and 1955–1984 periods of a hindcast run of OFES, confirming the result from the climatological sensitivity study. These results suggest that the SAF is another eddy hotspot when the wind stress curl keeps increasing.

Research on Optimal Control of Treadmill Shock Absorption Based on Ground Reaction Force Constraint

Research shows that treadmill shock-absorbing devices can reduce the impact of ground reaction forces on the knee and ankle joints during running. Most existing treadmills use fixed or passive shock absorption, meaning their shock-absorbing systems do not actively adjust to changes in ground reaction forces (GRFs). Methods: This study establishes a mathematical model integrating human motion biomechanics and treadmill running surfaces, analyzing the relationships between various parameters affecting the system. Ultimately, an optimal shock-absorbing treadmill control system is designed, utilizing a microcontroller as the main control unit, airbags for shock absorption, and a widely used foot pressure testing system. Objective: The goal is to more effectively prevent running injuries caused by excessive foot pressure. Compared to conventional shock absorption systems, this design features an active multilevel adjustment function with higher precision in regulation. Results: The experimental results demonstrate that the ground reaction force (GRF) generated by the optimal shock-absorbing treadmill control system is reduced by up to 10% compared to that of a conventional shock-absorbing treadmill. Conclusions: This leads to a smaller impact force on the knees due to foot pressure, resulting in better injury prevention outcomes.

Change in sprint cycling torque is not associated with change in isometric force following six weeks of sprint cycling and resistance training in strength-trained novice cyclists.

Strong relationships exist between sprint cycling torque and isometric mid-thigh pull (IMTP) force production at one timepoint; however, the relationships between the changes in these measures following a training period are not well understood. Accordingly, this study examined the relationships in the changes of sprint cycling torque and IMTP force following six-weeks of sprint cycling and resistance training performed by strength-trained novice cyclists (n=14). Cycling power, cadence, torque and IMTP force (Peak force [PF]/torque, average and peak rate of force/torque development [RFD/RTD], and RFD/RTD from 0 to 100ms and 0-200ms) were assessed before and after training. Training consisted of three resistance and three sprint cycling sessions per week. Training resulted in improvements in IMTP PF (13.1%) andRFD measures (23.7%-32.5%), cycling absolute (10.7%) and relative (10.5%) peak power, peak torque (11.7%) and RTD measures (27.9%-56.7%). Strong-to-very strong relationships were observed between cycling torque and IMTP force measures pre- (r=0.57-0.84; p<0.05) and post-training (r=0.63-0.87; p<0.05), but no relationship (p>0.05) existed between training-induced changes in cycling torque and IMTP force. Divergent training-induced changes in sprint cycling torque and IMTP force indicate that these measures assess distinct neuromuscular attributes. Training-induced changes in IMTP force are not indicative of training-induced changes in sprint cycling torque.

Characterizing Rock-Breaking Performance of PDC Cutters via Stability Metrics and Energy consumption in FDEM Simulations

As oil production increasingly transitions from shallow to deep formation, the need for efficient PDC cutters to drill through deep hard rock becomes paramount. Currently, there is a lack of effective methods for optimizing cutter shapes and their cutting parameters. This study addresses this gap by developing a rock-breaking mechanism model for PDC cutters and proposing a Stability Index (SI) based on cutting force variations during the cutting process. Using the FDEM method, we simulated the rock-breaking processes of planar, stinger, and machete cutters under various cutting depths and angles. SI and Mechanical Specific Energy (MSE) were employed as evaluation metrics to analyze the rock-breaking characteristics and determine the optimal cutting parameters for each cutter type. The results indicate that at shallow cutting depths, cutting force changes are minimal, predominantly causing plastic damage to the rock, resulting in lower stress and reduced wear on the PDC cutters. Conversely, at greater cutting depths, significant fluctuations in cutting force occur, leading to brittle failure and the generation of large cuttings. This sudden increase in cutting force can accelerate rock breaking but also increases the risk of cutter wear. Our findings suggest that the planar cutter offers stable performance with high cutting force requirements, optimal at a cutting depth of 1.5 mm and an angle of less than 20°. The stinger cutter, requiring lower cutting forces, performs best at a cutting depth of 2 mm and an angle of 20°. The machete cutter exhibits characteristics similar to the stinger cutter at shallow depths and the planar cutter at deeper depths, making it suitable for drilling at a depth of 2 mm and an angle of less than 10°. By balancing SI and MSE, this study provides a comprehensive approach to optimizing PDC cutter performance, enhancing drilling efficiency while minimizing cutter wear.

ПІДВИЩЕННЯ ГАЛЬМІВНОЇ ЗДАТНОСТІ ЛОКОМОТИВА ПРОМИСЛО-ВОГО ТРАНСПОРТУ З УРАХУВАННЯМ ЗУСИЛЬ У ЙОГО ЗЧІПНИХ ПРИСТРОЯХ

Objective: substantiation the rational concept of increasing the braking capacity of the industrial locomotive in transient modes of train movement, taking into account the force factor in its coupling device. Methodology of the work: theoretical studies of the energy from the deformation of the coupling devices of the industrial locomotive in the transient modes of train movement; theoretical studies of excessive coupling of locomotive wheels with rails in the presence of force on the locomotive's coupling device; determination of kinematic and dynamic parameters of the transient mode of train movement. A mathematical model of the train motion transitory process has been developed, it using the example of locomotive braking process, which allows determining the current values of train element velocities, as well as coupling forces, and has a low average discrepancy with the data of the technological calculation of industrial locomotive. Fixed: the force on the coupling device of the locomotive changes with a high frequency. The braking process is conventionally divided into 3 stages, which are characterized by oscillations, stabilization and a drop in clutch force; the energy corresponding to the change in force in the clutch during braking falls on 90.5% of the first and second stages. Taking into account the obtained results, the conceptual adjustment of the force of the coupling of the wheel pairs of the locomotive with the rails at the level of the maximum forces in the coupling device of the locomotive, determined by the simulation results, is adopted. Scientific novelty: improvement of the method of determining the required force of the traction the wheels of locomotive with the rails by taking into account the energy corresponding to the change in the effort in the coupling device of the locomotive during the braking time of the train. Practical value: the development of an improved concept by regulating the force the traction of locomotive wheel pairs with rails in transient modes of train movement, taking into account the energy assessment of the effort in the locomotive's coupling device.

Analysis of Landing Buffer Characteristics of Unmanned Airdrop Rescue Vehicle

Taking an unmanned airdrop rescue vehicle as the research object, in order to reduce the impact overload of the airdrop landing, the exhaust type airbag buffer mode suitable for the airdrop vehicle is determined. Firstly, the scheme of the airdrop system is designed. According to the basic assumption of the airdrop process, the thermodynamic analysis model of the buffer bag is derived and the parameters are designed. Secondly, the finite element model of airdrop system with airbag buffer is established based on the airbag finite element algorithm (CV method). Finally, the buffering effect is evaluated by analyzing the change of tire force. The calculation results show that the system overload is reduced from 35g to 22g by using airbag buffer, and the buffer effect is obvious.

Significantly enhanced specific activity of Bacillus subtilis (2,3)-butanediol dehydrogenase through computer-aided refinement of its substrate-binding pocket

(2,3)-Butanediol dehydrogenases (BDHs) are widely utilized for the stereoselective interconversion between α-hydroxy ketones and vicinal diols to produce various functional building blocks. In this study, to enhance the specific activity towards (R)-phenyl-1,2-ethanediol (1a) for 2-hydroxyacetophenone (1b), the substrate-binding pocket of a Bacillus subtilis BDH (BsBDHA) was refined through site-directed mutagenesis. Based on molecular docking simulations, 14 residues were identified and subjected to alanine scanning mutagenesis. After screening, two residues, His42 and Gly292, were singled out for partial site-saturation mutagenesis. The results revealed that BsBDHAH42A and BsBDHAG292A displayed high activities of 3.21 and 1.97 U/mg, respectively. Employing combinatorial mutagenesis, a superior mutant, BsBDHAI49L/V266L/G292A, was developed, exhibiting significantly enhanced specific activity and catalytic efficiency towards (R)-1a, achieving 14.81 U/mg and 4.47 mM−1 s−1, respectively, which were 27.4- and 55.9-fold higher than those of BsBDHA. Further substrate spectrum analysis revealed that the superior mutant displayed increased specific activities for (R)-2a–6a by 1.4- to 10.3-fold. The integration of BsBDHAI49L/V266L/G292A into a three-enzymatic cascade for the synthesis of 1b effectively elevated the yield from 58.1 to 82.4%. Molecular mechanism analysis indicated that the mutation-induced changes in intermolecular forces resulted in a higher frequency of reactive conformations for (R)-1a in BsBDHAI49L/V266L/G292A compared to BsBDHA.