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Pan, Chaofeng, Yuanxue Tao, Limei Wang, Huanhuan Li, and Jufeng Yang. "Fuzzy energy management strategy for electric vehicle combining driving cycle construction and air-conditioning load identification." Advances in Mechanical Engineering 13, no. 2 (February 2021): 168781402199438. http://dx.doi.org/10.1177/1687814021994381.
Повний текст джерелаАнотація:
Energy management strategy is developed by considering the random and air conditioning load fluctuation, which greatly affected the torque control of the electric motor in electric vehicle. Firstly, the vehicle power consumption model is established, based on the influencing factors of electric vehicle energy consumption: random load and air conditioning load. Therefore, driving conditions with random characteristics representing the actual random load are constructed. According to the clustered characteristic parameters, the driving conditions were classified as different driving modes. Secondly, the mode of predicted condition was taken as a variable to evaluate the logic threshold strategy and fuzzy control strategy in which the influence of air conditioning was considered. Finally, under the condition of New European Driving Cycle (NEDC), the proposed management strategy was simulated in software environment, and the hardware in-loop (HIL) test was performed to verify the strategy. The simulation and HIL test results show that the proposed energy management strategy can increase the driving range by considering the load fluctuation of air conditioning. Furthermore, the strategy combining the driving mode prediction can alleviate the decline rate of SOC. And the fuzzy control strategy has better adaptability in complex conditions and lower battery energy consumption rate.
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Zhang, Bing Zhan, Han Zhao, and An Dong Yin. "Depleting Mode Control Strategies for Plug-in Hybrid Electric Vehicles." Applied Mechanics and Materials 130-134 (October 2011): 2211–15. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.2211.
Повний текст джерелаАнотація:
Control strategy is the most important issue in the Plug-in Hybrid electric vehicles (PHEV) design, which has two modes: charge depleting mode (CD) and charge sustaining mode (CS). The different control strategies in depleting mode will have a great influence on PHEV dynamic performance and fuel economy. The engine optimal torque control strategy was proposed in the paper. The vehicle simulation model in Powertrain Systems Analysis Toolkit (PSAT) was adopted to evaluate the proposed control strategy. The aggressive highway drive cycle Artemis_hwy and a random drive cycle generated by Markov Process were used. The simulation results indicate the proposed control strategy has great improvement in fuel economy.
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Antar, Bilal I., and Hong Tae Kang. "Fatigue Life Prediction for Caliper Guide Pin under Random Vibrational Loading." Advanced Materials Research 891-892 (March 2014): 1755–60. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.1755.
Повний текст джерелаАнотація:
A fatigue life prediction tool was developed for caliper guide pins under random vibrational loading. The Pie-Slice model was designed to provide detailed information about the failure location, orientation, and damage magnitude. A component test fixture was developed to determine the strain-life curve for a given guide pin design. Statistical analysis was conducted to insure the repeatability of the failure mode and the robustness of the setup. Weibull analysis was performed to the measured guide pin strain-life in order to insure that the developed strain-life data to insure that developed strain-life curve will account for all the manufacturing process variations, from a component, assembly, and a system level to a certain level of reliability and confidence. Rainflow cycle count was used to bin the damaging and non-damaging cycles based on their stain level. Fatigue life calculation was performed using the Smith-Watson-Topper strain-life approach. The predictive tool was able to accurately estimate the cumulative fatigue damage for guide pins under random loading conditions. The Pie-Slice model was also able to predict the failure location and orientation of a crack, as well as the damage magnitude. Both tools were validated using a pre-designed random block-load sequence at constant amplitude..
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MAZZINI, G., G. SETTI, and R. ROVATTI. "MULTIMODE TIME-MARKOV SYSTEMS: RECURSIVE TENSOR-BASED ANALYSIS, CHAOTIC GENERATION, LOCALLY LOOPING PROCESSES." International Journal of Bifurcation and Chaos 16, no. 04 (April 2006): 961–88. http://dx.doi.org/10.1142/s0218127406015234.
Повний текст джерелаАнотація:
The paper proposes a systematic solution to the problem of mixing different stochastic processes, each implied by a certain mode of operation of the system at hand and with a random duration whose distribution depends on the previous and present modes. We do so by widening the scope of an existing framework for the statistical characterization of finite valued processes with memory-one properties. The point of view is that of stochastic dynamics and the state space of the process is partitioned into regions (that we identify with modes) such that, if sojourn in a mode can be assumed, the statistical characterization is fully understood. The process is also allowed to stochastically move from one mode to another and the number of time steps for which it remains in each mode is a random variable whose distribution is a function only of the mode visited before. A general theoretical framework is developed here for the computation of any-order joint probabilities. The framework is then exemplified for the case of locally looping systems that are random sequences of modes comprising the cyclical execution of given atomic actions. They are the model of choice for complex appliances that operate following the steps of a communication protocol, and/or the various phases of a bus cycle, and/or the load-compute-store mechanism of a microprocessor, etc. Exploiting the theory put forward by the paper, we highlight how these processes could be generated by suitably designed 2-d chaotic maps and how their second- and third-order spectra may be obtained and interpreted when exponentially or polynomially decaying distributions are assumed for mode sojourn times.
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Xu, Fei, Chuanri Li, and Tongmin Jiang. "On the Shaker Simulation of Wind-Induced Non-Gaussian Random Vibration." Shock and Vibration 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/5450865.
Повний текст джерелаАнотація:
Gaussian signal is produced by ordinary random vibration controllers to test the products in the laboratory, while the field data is usually non-Gaussian. Two methodologies are presented in this paper for shaker simulation of wind-induced non-Gaussian vibration. The first methodology synthesizes the non-Gaussian signal offline and replicates it on the shaker in the Time Waveform Replication (TWR) mode. A new synthesis method is used to model the non-Gaussian signal as a Gaussian signal multiplied by an amplitude modulation function (AMF). A case study is presented to show that the synthesized non-Gaussian signal has the same power spectral density (PSD), probability density function (PDF), and loading cycle distribution (LCD) as the field data. The second methodology derives a damage equivalent Gaussian signal from the non-Gaussian signal based on the fatigue damage spectrum (FDS) and the extreme response spectrum (ERS) and reproduces it on the shaker in the closed-loop frequency domain control mode. The PSD level and the duration time of the derived Gaussian signal can be manipulated for accelerated testing purpose. A case study is presented to show that the derived PSD matches the damage potential of the non-Gaussian environment for both fatigue and peak response.
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Singh, Salvinder, and Shahrum Abdullah. "Durability analysis using Markov chain modeling under random loading for automobile crankshaft." International Journal of Structural Integrity 10, no. 4 (August 12, 2019): 454–68. http://dx.doi.org/10.1108/ijsi-03-2018-0016.
Повний текст джерелаАнотація:
Purpose The purpose of this paper is to present the durability analysis in predicting the reliability life cycle for an automobile crankshaft under random stress load using the stochastic process. Due to the limitations associated with the actual loading history obtained from the experimental analysis or due to the sensitivity of the strain gauge, the fatigue reliability life cycle assessment has lower accuracy and efficiency for fatigue life prediction. Design/methodology/approach The proposed Markov process embeds the actual maximum and minimum stresses by a continuous updating process for stress load history data. This is to reduce the large credible intervals and missing loading points used for fatigue life prediction. With the reduction and missing loading intervals, the accuracy of fatigue life prediction for the crankshaft was validated using the statistical correlation properties. Findings It was observed that fatigue reliability corresponded well by reporting the accuracy of 95–98 per cent with a mean squared error of 1.5–3 per cent for durability and mean cycle to failure. Hence, the proposed fatigue reliability assessment provides an accurate, efficient, fast and cost-effective durability analysis in contrast to costly and lengthy experimental techniques. Research limitations/implications An important implication of this study is durability-based life cycle assessment by developing the reliability and hazard rate index under random stress loading using the stochastic technique in modeling for improving the sensitivity of the strain gauge. Practical implications The durability analysis is one of the fundamental attributes for the safe operation of any component, especially in the automotive industry. Focusing on safety, structural health monitoring aims at the quantification of the probability of failure under mixed mode loading. In practice, diverse types of protective barriers are placed as safeguards from the hazard posed by the system operation. Social implications Durability analysis has the ability to deal with the longevity and dependability of parts, products and systems in any industry. More poignantly, it is about controlling risk whereby engineering incorporates a wide variety of analytical techniques designed to help engineers understand the failure modes and patterns of these parts, products and systems. This would enable the automotive industry to improve design and increase the life cycle with the durability assessment field focussing on product reliability and sustainability assurance. Originality/value The accuracy of the simulated fatigue life was statistically correlated with a 95 per cent boundary condition towards the actual fatigue through the validation process using finite element analysis. Furthermore, the embedded Markov process has high accuracy in generating synthetic load history for the fatigue life cycle assessment. More importantly, the fatigue reliability life cycle assessment can be performed with high accuracy and efficiency in assessing the integrity of the component regarding structural integrity.
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Jiang, Shanhe, Chaolong Zhang, and Shijun Chen. "Sequential Hybrid Particle Swarm Optimization and Gravitational Search Algorithm with Dependent Random Coefficients." Mathematical Problems in Engineering 2020 (April 21, 2020): 1–17. http://dx.doi.org/10.1155/2020/1957812.
Повний текст джерелаАнотація:
Particle swarm optimization (PSO) has been proven to show good performance for solving various optimization problems. However, it tends to suffer from premature stagnation and loses exploration ability in the later evolution period when solving complex problems. This paper presents a sequential hybrid particle swarm optimization and gravitational search algorithm with dependent random coefficients called HPSO-GSA, which first incorporates the gravitational search algorithm (GSA) with the PSO by means of a sequential operating mode and then adopts three learning strategies in the hybridization process to overcome the aforementioned problem. Specifically, the particles in the HPSO-GSA enter into the PSO stage and update their velocities by adopting the dependent random coefficients strategy to enhance the exploration ability. Then, the GSA is incorporated into the PSO by using fixed iteration interval cycle or adaptive evolution stagnation cycle strategies when the swarm drops into local optimum and fails to improve their fitness. To evaluate the effectiveness and feasibility of the proposed HPSO-GSA, the simulations were conducted on benchmark test functions. The results reveal that the HPSO-GSA exhibits superior performance in terms of accuracy, reliability, and efficiency compared to PSO, GSA, and other recently developed hybrid variants.
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Popov, Pavel P., Athanasios Sideris, and William A. Sirignano. "Stochastic modelling of transverse wave instability in a liquid-propellant rocket engine." Journal of Fluid Mechanics 745 (March 17, 2014): 62–91. http://dx.doi.org/10.1017/jfm.2014.96.
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AbstractThe combustion stability of a liquid-propellant rocket engine experiencing a random, finite perturbation from steady-state conditions is examined. The probability is estimated for a nonlinear resonant limit-cycle oscillation to be triggered by a random disturbance. Transverse pressure waves are considered by using a previously published two-dimensional nonlinear pressure wave equation coupled with Euler equations governing the velocity components. The cylindrical combustion chamber is a complex system containing multiple co-axial methane–oxygen injectors; each co-axial jet is analysed for mixing and burning on its own local grid scheme, with the energy release rate coupled to the wave oscillation on the more global grid. Two types of stochastic forcing for the random disturbance are explored: a travelling Gaussian pressure pulse and an oscillating pressure dipole source. The random variables describing the pulse are magnitude, location, duration and orientation of the disturbances. The polynomial chaos expansion (PCE) method is used to determine the long-time behaviour and infer the asymptote of the solution to the governing partial differential equations. Depending on the random disturbance, the asymptote could be the steady-state solution or a limit-cycle oscillation, e.g. a first tangential travelling wave mode. The asymptotic outcome is cast as a stochastic variable which is determined as a function of input random variables. The accuracy of the PCE application is compared with a Monte Carlo calculation and is shown to be significantly less costly for similar accuracy.
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Hoffmann, Ralf, Bernhard Hirt, Viviane Bechtold, Peter Beard, and Kenneth Raj. "Different Modes of Human Papillomavirus DNA Replication during Maintenance." Journal of Virology 80, no. 9 (May 1, 2006): 4431–39. http://dx.doi.org/10.1128/jvi.80.9.4431-4439.2006.
Повний текст джерелаАнотація:
ABSTRACT Human papillomavirus (HPV) begins its life cycle by infecting the basal cells of the epithelium. Within these proliferating cells, the viral genomes are replicated, maintained, and passed on to the daughter cells. Using HPV episome-containing cell lines that were derived from naturally infected cervical tissues, we investigated the mode by which the viral DNAs replicate in these cells. We observed that, whereas HPV16 DNA replicated in an ordered once-per-S-phase manner in W12 cells, HPV31 DNA replicated via a random-choice mechanism in CIN612 cells. However, when HPV16 and HPV31 DNAs were separately introduced into an alternate keratinocyte cell line NIKS, they both replicated randomly. This indicates that HPV DNA is inherently capable of replicating by either random-choice or once-per-S-phase mechanisms and that the mode of HPV DNA replication is dependent on the cells that harbor the viral episome. High expression of the viral replication protein E1 in W12 cells converted HPV16 DNA replication to random-choice replication and, as such, it appears that the mode of HPV DNA replication in proliferating cells is dependent on the presence or the increased level of this protein in the host cell. The implications of these observations on maintenance, latency, and persistence are discussed.
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Nurgaliyev, M. K., A. K. Saymbetov, B. N. Zholamanov, A. Т. Yeralkhanova, and G. B. Zhuman. "PREDICTING THE LIFETIME OF LORA BASED WIRELESS SENSOR NETWORKS USING A PROBABILISTIC MODEL OF MARKOV CHAINS." PHYSICO-MATHEMATICAL SERIES 2, no. 336 (April 15, 2021): 157–64. http://dx.doi.org/10.32014/2021.2518-1726.36.
Повний текст джерелаАнотація:
Real-time monitoring systems and sensors are not complete without wireless data transmission modules. Improving energy efficiency requires examining various system parameters that affect the power consumption of transmitting and receiving devices. The most important parameter of any autonomous wireless network is its uptime. In this work, we used LoRa wireless modules on the SX1278 chip manufactured by Semtech to determine their power consumption in various operating modes. The obtained data were used to build a consumption model of the device when connected to a receiver. Three operating modes are considered: transmit mode, receive mode and sleep mode. In an ideal communication channel, all transmitted data reaches the receiver with 100% probability. In a real situation, data reaches the receiver with a certain probability, depending on the communication channel, transmission power, distance to the addressee, and network parameters. In this work, the occurrence of an error is random. In this case, the occurrence of an error during reception entails a lack of confirmation of receipt or a request for re-sending data. Sending data again increases the power consumption of the device and, consequently, decreases the operating time of the wireless device. This paper shows the dependences of the operating time on various initial monitored parameters of the device, such as: confirmation timeout, packet length, time of one transmission cycle and the maximum number of retransmissions in one cycle. The developed model for predicting the consumption of the device can be used in the design of autonomous wireless sensor monitoring networks.
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Morishita, F., I. Hayashi, H. Matsuoka, K. Takahashi, K. Shigeta, T. Gyohten, M. Niiro, et al. "A 312-MHz 16-Mb random-cycle embedded DRAM macro with a power-down data retention mode for mobile applications." IEEE Journal of Solid-State Circuits 40, no. 1 (January 2005): 204–12. http://dx.doi.org/10.1109/jssc.2004.837986.
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Liu, Shifu, Jianming Ling, Yu Tian, Tianxin Hou, and Xindong Zhao. "Random Vibration Analysis of a Coupled Aircraft/Runway Modeled System for Runway Evaluation." Sustainability 14, no. 5 (February 28, 2022): 2815. http://dx.doi.org/10.3390/su14052815.
Повний текст джерелаАнотація:
Runway roughness is one of the most critical performance factors for runway evaluation, which directly impacts airport operation safety and pavement preservation cost. Properly evaluated runway roughness could optimize the decision-making process for runway preservation and therefore reduce the life cycle cost of the runway pavement asset. In this paper, the excitation effect of runway roughness is analyzed using a coupled aircraft/runway system. The coupled system is composed of a two degrees-of-freedom (2-DOF) aircraft model and a typical asphalt runway structure model established under runway roughness random excitation in this work. The dynamic differential equations for the coupled system are derived based on D’Alembert’s principle. The system’s vibration responses are determined via the pseudo excitation method and three response laws, i.e., the center of gravity acceleration (CGA), the dynamic load coefficient (DLC) of the landing gear, and the runway structural displacement, which are investigated under different modes. The results show that the first-order mode of the runway structure, vertical deformation, is the most significant of the four modes. Moreover, uneven excitation has a significant effect on the distribution of the aircraft’s vibration response. Compared with a single aircraft system, the developed coupled aircraft/runway system has different dynamic responses, and the degree of difference depends on the taxiing speed. The coupled effect on the CGA increases significantly with an increase in speed, with up to a 7.3% percentage difference. The coupled effect on the DLC first increases and then decreases as the aircraft speed increases, reaching a maximum of about 6% percentage difference at 120 km/h.
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Upadhyay, Ranjit Kumar, Argha Mondal, and Wondimu W. Teka. "Mixed Mode Oscillations and Synchronous Activity in Noise Induced Modified Morris–Lecar Neural System." International Journal of Bifurcation and Chaos 27, no. 05 (May 2017): 1730019. http://dx.doi.org/10.1142/s0218127417300191.
Повний текст джерелаАнотація:
The modified three-dimensional (3D) Morris–Lecar (M–L) model is very useful to understand the spiking activities of neurons. The present article addresses the random dynamical behavior of a modified M–L model driven by a white Gaussian noise with mean zero and unit spectral density. The applied stimulus can be expressed as a random term. Such random perturbations are represented by a white Gaussian noise current added through the electrical potential of membrane of the excitatory principal cells. The properties of the stochastic system (perturbed one) and noise induced mixed mode oscillation are analyzed. The Lyapunov spectrum is computed to present the nature of the system dynamics. The noise intensity is varied while keeping fixed the predominant parameters of the model in their ranges and also observed the changes in the dynamical behavior of the system. The dynamical synchronization is studied in the coupled M–L systems interconnected by excitatory and inhibitory neurons with noisy electrical coupling and verified with similarity functions. This result suggests the potential benefits of noise and noise induced oscillations which have been observed in real neurons and how that affects the dynamics of the neural model as well as the coupled systems. The analysis reports that the modified M–L system which has the limit cycle behavior can show a type of phase locking behavior which follows either period adding (i.e. 1:1, 2:1, 3:1, 4:1) sequences or Farey sequences. For the coupled neural systems, complete synchronization is shown for sufficient noisy coupling strength.
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OUYANG, YING, ZHAOMAN WAN, and ZHONG WAN. "GAME MODEL FOR ONLINE AND OFFLINE RETAILERS UNDER BUY-ONLINE AND PICK-UP-IN-STORE MODE WITH DELIVERY COST AND RANDOM DEMAND." ANZIAM Journal 62, no. 1 (January 2020): 62–88. http://dx.doi.org/10.1017/s1446181120000127.
Повний текст джерелаАнотація:
Online retailers are increasingly adding buy-online and pick-up-in-store (BOPS) modes to order fulfilment. In this paper, we study a system of BOPS by developing a stochastic Nash equilibrium model with incentive compatibility constraints, where the online retailer seeks optimal online sale prices and an optimal delivery schedule in an order cycle, and the offline retailer pursues a maximal rate of sharing the profit owing to the consignment from the online retailer. By an expectation method and optimality conditions, the equilibrium model is first transformed into a system of constrained nonlinear equations. Then, by a case study and sensitivity analysis, the model is validated and the following practical insights are revealed. (I) Our method can reliably provide an equilibrium strategy for the online and offline retailers under BOPS mode, including the optimal online selling price, the optimal delivery schedule, the optimal inventory and the optimal allocation of profits. (II) Different model parameters, such as operational cost, price sensitivity coefficient, cross-sale factor, opportunity loss ratio and loss ratio of unsold goods, generate distinct impacts on the equilibrium solution and the profits of the BOPS system. (III) Optimization of the delivery schedule can generate greater consumer surplus, and makes the offline retailer share less sale profit from the online retailer, even if the total profit of the BOPS system becomes higher. (IV) Inventory subsidy is an indispensable factor to improve the applicability of the game model in BOPS mode.
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Zhang, Jin, Zhiting Lin, Xiulong Wu, Chunyu Peng, Wenjuan Lu, Qiang Zhao, and Junning Chen. "An 8T SRAM Array with Configurable Word Lines for In-Memory Computing Operation." Electronics 10, no. 3 (January 27, 2021): 300. http://dx.doi.org/10.3390/electronics10030300.
Повний текст джерелаАнотація:
In-memory computing (IMC) has been widely accepted to be an effective method to improve energy efficiency. To realize IMC, operands in static random-access memory (SRAM) are stored in columns, which contradicts SRAM write patterns and requires additional data movement. In this paper, an 8T SRAM array with configurable word lines is proposed, in where the operands are arranged in rows, following the traditional SRAM storage pattern, and therefore additional data movement is not required. The proposed structure supports three different computing modes. In the ternary multiplication mode, the reference voltage generation column is not required. The energy of computing is only 1.273 fJ/bit. In the unsigned multibit multiplication mode, discharge and charging paths are used to enlarge the voltage difference of the least significant bit. In the logic operation mode, different types of operations (e.g., IMP, OR, NOR, XNOR, and XOR) are achieved in a single cycle. The frequency of logic computing is up to 909 MHz.
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Sun, YuanTao, Chao Liu, Qing Zhang, and XianRong Qin. "Multiple Failure Modes Reliability Modeling and Analysis in Crack Growth Life Based on JC Method." Mathematical Problems in Engineering 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/2068620.
Повний текст джерелаАнотація:
The fatigue crack growth (FCG) phenomenon generally exists in large mechanical structures. Due to the influences of varied kinds of random factors, the safety evaluation of structure in FCG is under great uncertainty. In this paper, based on the reliability theory, the limit state equations of fracture failure and static strength failure were derived firstly, and the parameters in those equations were regarded as random variables that follow the normal distribution or log-normal distribution. According to the limit state equations, the JC method (equivalent normalizing method) was used to calculate the reliability indexes under the different failure modes of structure in every stress cycle. Based on the reliability indexes and correlation of the two failure modes, the joint failure probability was obtained. In the end, a specific computation example was given, and the curve of joint failure probability in multiple failure modes was used for comparison with the result of single failure mode. The results indicated that the reliability analysis based on multiple failure modes was more reasonable, and the evaluation of reliability could be obtained in fatigue crack growth process.
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Apryshkin, A. S., and G. S. Khazanovich. "Determination of capacity and comfort indicators of a passenger elevator." SAFETY OF TECHNOGENIC AND NATURAL SYSTEMS, no. 1 (2021): 38–50. http://dx.doi.org/10.23947/2541-9129-2021-1-38-50.
Повний текст джерелаАнотація:
Introduction. Elevators are mass weight-handling units used by millions of residents of multi-storey buildings. Safety of elevator units and comfort of their use are determined not only by the correct choice of their design and parameters, but first of all, by the organization of the maintenance system. Each elevator is an individual unit that serves a residential building with a specific number of passengers, number of floors and other features. However, regulatory documents recommend standard maintenance plans. There is the need to establish the relationship between the loading modes of the main components and the optimal scheme of technical and repair works. The present work is devoted to the solution of this problem, along with the study of transport comfort. Problem Statement. The operation of the elevator in a residential building with a number of floors N occurs in separate cycles. Standing, lift call, and destination floors are random variables for which probabilistic characteristics must be reliably established. In general, the elevator operation mode includes three stages: calling to the passenger boarding level, moving with passengers to the destination level, and waiting for the next cycle. There are stops inside the movement stages. The specific problem of mathematical description of the random process of implementing the operating characteristics of the main drive of the elevator is reduced to two directions: 1) the development of mathematical models for the formation of the main indicators of the main elevator drive load during the cycle (net machine time τmi and the number of switches n)i; 2) the study of the relationship between passenger traffic, building residential density and cycle duration. Theoretical Part. To meet these objectives the authors have performed the studies of the following main processes characterizing the functioning of the lift, the level of capacity of the transport drive and comfort: the development of mathematical models of formation of indicators of the elevator drive load; the establishment of the relationship of traffic flow, residential density and the duration of the cycle; development of methodology for calculation of the number of flights went by the elevator in different modes; development of methods of calculating the transport comfort indicator; justification of the structure of the algorithm for modeling the operating modes of the elevator. Conclusion. The paper provides the results, which complement the theoretical provisions for determining the capacity and transport comfort of elevators.
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de Freitas, Verônica, and Luzenira Alves Brasileiro. "VIABILIDADE DOS MODOS NÃO MOTORIZADOS." Revista Sinergia 20, no. 4 (December 31, 2000): 303–10. http://dx.doi.org/10.33780/issn.2177-451x.2019.v20.n4.p303-310.
Повний текст джерелаАнотація:
Traffic is getting increasingly chaotic and the jams are getting more and more frequent in such way that people's lives in cities are being affected with reduced quality of life due to the time spent to come and go for everyday tasks, therefore the importance of studying traffic demands for installation of cycle routes in order to contribute to the reduce the usage of motorized vehicles. This case study was held in the city of Presidente Epitácio-SP, applying 1763 questionnaires which were applied in a total of 41.511 inhabitants. The number of questionnaires that were applied were defined by the statistical method Simple Random Sampling (AAS). These data from the questionnaires resulted in matrices source destination, S/D, via Google Maps software, which allowed the research to obtain the main mode used, and the greater flow routes. Non-motorized modes predominated in results in 50%, thus clearly showing the necessity for cycle lanes in the aforementioned town.
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Liang, Geng, and Xin An. "Simulation analysis of communication performance of PROFIBUS in single and multiple master mode." Measurement and Control 53, no. 7-8 (June 10, 2020): 1238–49. http://dx.doi.org/10.1177/0020294020927420.
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With the application of digital information technology and communication technology, industrial intelligence and integration also began to develop rapidly, and the importance of the research on bus communication in industrial control communication also increased. As the first international bus standard, PROFIBUS has been widely used in the field of industrial control; in recent years, it was mainly used to connect devices to the control layer and convert data through token transmission. Based on the understanding of the transmission mechanism of PROFIBUS fieldbus protocol, this article carries out a simulation study on its communication performance. Through analysis of the data link layer, changing the target token cycle time (high and low priority) and random setting each site message number, as well as the number of master station and slave station, how the main token latency and packet loss rate and efficiency of bus affect the change of performance parameters was observed. For multiple communication systems, the relationship between the address value on the main token ring and transport performance is found by experiments on the site address value on the main token ring and the target token cycle time value. Finally, the scheduling algorithm is applied to the communication scheduling of PROFIBUS fieldbus. The results confirm that the scheduling algorithm has better transmission efficiency than the traditional MAC media access protocol under the condition that the load rate does not exceed 100%, which makes up for the shortcomings of the original PROFIBUS bus system and makes the communication performance better.
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Sun, Yong, Xingsheng Li, and Hua Guo. "Failure Probability Prediction of Thermally Stable Diamond Composite Tipped Picks in the Cutting Cycle of Underground Roadway Development." Applied Sciences 9, no. 16 (August 11, 2019): 3294. http://dx.doi.org/10.3390/app9163294.
Повний текст джерелаАнотація:
The Thermally Stable Diamond Composite (TSDC) tipped pick has been developed to replace Tungsten Carbide (WC) tipped picks for hard rock cutting. Due to the material properties of TSDC, a major failure mode of TSDC tipped picks during rock cutting is random failures caused by excessive bending force acting on the cutting tips. A probabilistic approach has been proposed to estimate the failure probability of picks with this failure mode. However, there are two limitations in existing research: only one drum revolution is considered, and the variation of rock thickness is ignored. This study aims to extend the current approach via removing these limitations, based on the failure probability analysis of picks over a full cutting cycle in the underground coal mining roadway development process. The research results show that both drum advance direction and the variation of rock thickness have significant impacts on pick failure probability. The extended approach can be used to estimate pick failure probability for more realistic scenarios in real applications with improved accuracy. Although the study focused on TSDC tipped picks, the developed approach can also be applied to other types of picks.
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Pupin, M., G. Vergani, M. Lima, K. Silva, A. Monteiro, A. Ramos, R. Batista, W. Vicente, M. Oliveira, and J. Fonseca. "227 Is the antral follicle count on a random day of the oestrous cycle correlated with superovulatory responses in Santa Inês ewes?" Reproduction, Fertility and Development 32, no. 2 (2020): 241. http://dx.doi.org/10.1071/rdv32n2ab227.
Повний текст джерелаАнотація:
Antral follicle count (AFC) performed after an oestrus synchronization protocol has been studied as a tool to select ewes with high potential for invivo embryo production (Pinto et al. 2018 Theriogenology 113, 146-152). However, it would be interesting to know whether AFC assessed on a random day of the oestrous cycle correlates with the superovulatory response. The present study was conducted to evaluate the correlation between AFC at the beginning of progesterone (P4)-based oestrus synchronization protocol used as basis of superovulatory treatment and the number of corpora lutea (CL) 12h before recovery of embryos in Santa Inês ewes. The study was conducted during September and October in northeast Brazil (03°40′26″S and 40°14′20″W) using 8 adult Santa Inês ewes. On a random day of oestrous cycle (Day 0) all ewes received an intravaginal device (CIDR) of progesterone (0.3g, Eazi-breed, Zoetis), which remained for 9 days. On Day 7, the pFSH (133mg, Folltropin V, Vetoquinol) treatment began, with 6 decreasing doses (25, 25, 15, 15, 10, and 10%) injected IM at 12-h intervals. On Day 9, 2 equal doses of D-cloprostenol were injected at a 12-h interval (37.5µg, Prolise, Agener União). All ewes showed oestrus and were mated by fertile rams. Flunixin meglumine (24.9 mg; Banamine, MSD Animal Health) was administered IM on Days 12, 13, and 15. On Day 16, non-surgical embryo recovery (NSER) was performed after cervical dilation using D-cloprostenol and oestradiol benzoate at 16h and oxytocin 20min before. Transrectal B-mode ultrasound evaluations (Z5 Vet, Mindray), frequency 7.5MHz, were performed on Day 0 and 7 and 12h before NSER to evaluate the ovarian population present. Pearson correlation analysis (P<0.05) was performed using Bioestat 5.3 software. The number of AFC per ewe at the beginning of the protocol and on Day 7 were 9.9±2.7 and 11±3.2, respectively. The numbers of CL, recovered embryos, and viable embryos were 14.0±3.5, 8.2±10.9, and 6.0±11.0, respectively. There was no correlation of AFC on a random day of oestrous cycle with the number of AFC on Day 7 (P=0.42), number of corpora lutea (P=0.44), number of recovered embryos (P=0.18), or number of viable embryos (P=0.11) in superovulated ewes. In conclusion, we did not find significant correlations between AFC on a random day of oestrous cycle and the superovulatory/embryos response in Santa Inês ewes. Financial support for this study was provided by Embrapa (02.13.06.026.00.02 and 02.13.06.026.00.04) and FAPEMIG (PPM 00201-17).
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PETRACCHI, DONATELLA, MICHELE BARBI, SANTI CHILLEMI, ELENI PANTAZELOU, DAVID PIERSON, CHRIS DAMES, LON WILKENS, and FRANK MOSS. "A TEST FOR A BIOLOGICAL SIGNAL ENCODED BY NOISE." International Journal of Bifurcation and Chaos 05, no. 01 (February 1995): 89–100. http://dx.doi.org/10.1142/s0218127495000077.
Повний текст джерелаАнотація:
We consider here a simple example of stimulated sensory neurons operating under the influence of their own internal noise: the hair mechanoreceptor of the crayfish stimulated by a weak, periodic, hydrodynamic signal. Action potential spike trains from the sensory neuron are recorded and assembled into two objects for analysis: the interspike interval histogram (ISIH) and the cycle histogram of the spike density. A time transformation is carried out on the ISIH’s in order to test the hypothesis that the spike train is basically random and that the probability of coherent spike generation is related to the instantaneous stimulus amplitude. Moreover it is shown that the physiological spike train data can be qualitatively mimicked by an electronic Fitzhugh-Nagumo model, operated in the subcritical mode, driven by noise and a weak periodic signal. A discussion of how the Fitzhugh-Nagumo model is properly operated to mimic noisy data from sensory neurons is included.
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Jiang, Shang, Hongjin Liu, Zucheng Gu, and Qun Liu. "Mechanical Simulation Analysis of Aerospace High Reliability Electronic Equipment." Journal of Physics: Conference Series 2187, no. 1 (February 1, 2022): 012035. http://dx.doi.org/10.1088/1742-6596/2187/1/012035.
Повний текст джерелаАнотація:
Abstract In order to meet the requirements of high reliability, the structural performance of aerospace electronic equipment must meet the requirements of long-term stable work under severe mechanical conditions. The finite element model of electronic equipment from structural frame to printed circuit board and important components is established in detail. The mechanical analysis of the whole machine under the working conditions of modal analysis, random vibration and sinusoidal vibration is carried out, and the natural frequency, vibration mode and corresponding stress-strain data of each component are obtained. Through the PCB deformation check and structural strength check, the design safety margin of the whole machine is obtained. The analysis results provide the design basis for the structure finalization of aerospace electronic equipment, shorten the research and development cycle, reduce the experimental cost, and have important significance for the structure design of electronic equipment.
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Zhou, Wenjuan, and Li Wang. "The Energy-Efficient Dynamic Route Planning for Electric Vehicles." Journal of Advanced Transportation 2019 (August 26, 2019): 1–16. http://dx.doi.org/10.1155/2019/2607402.
Повний текст джерелаАнотація:
Aiming to provide an approach for finding energy-efficient routes in dynamic and stochastic transportation networks for electric vehicles, this paper addresses the route planning problem in dynamic transportation network where the link travel times are assumed to be random variables to minimize total energy consumption and travel time. The changeable signals are introduced to establish state-space-time network to describe the realistic dynamic traffic network and also used to adjust the travel time according to the signal information (signal cycle, green time, and red time). By adjusting the travel time, the electric vehicle can achieve a nonstop driving mode during the traveling. Further, the nonstop driving mode could avoid frequent acceleration and deceleration at the signal intersections so as to reduce the energy consumption. Therefore, the dynamically adjusted travel time can save the energy and eliminate the waiting time. A multiobjective 0-1 integer programming model is formulated to find the optimal routes. Two methods are presented to transform the multiobjective optimization problem into a single objective problem. To verify the validity of the model, a specific simulation is conducted on a test network. The results indicate that the shortest travel time and the energy consumption of the planning route can be significantly reduced, demonstrating the effectiveness of the proposed approaches.
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Jingade, Naveen, and Nishant K. Singh. "Mean field dynamo action in shear flows. I: fixed kinetic helicity." Monthly Notices of the Royal Astronomical Society 495, no. 4 (May 1, 2020): 4557–69. http://dx.doi.org/10.1093/mnras/staa1204.
Повний текст джерелаАнотація:
ABSTRACT We study mean field dynamo action in a background linear shear flow by employing pulsed renewing flows with fixed kinetic helicity and non-zero correlation time (τ). We use plane shearing waves in terms of time-dependent exact solutions to the Navier–Stokes equation as derived by Singh & Sridhar (2017). This allows us to self-consistently include the anisotropic effects of shear on the stochastic flow. We determine the average response tensor governing the evolution of mean magnetic field, and study the properties of its eigenvalues that yield the growth rate (γ) and the cycle period (Pcyc) of the mean magnetic field. Both, γ and the wavenumber corresponding to the fastest growing axisymmetric mode vary non-monotonically with shear rate S when τ is comparable to the eddy turnover time T, in which case, we also find quenching of dynamo when shear becomes too strong. When $\tau /T\sim {\cal O}(1)$, the cycle period (Pcyc) of growing dynamo wave scales with shear as Pcyc ∝ |S|−1 at small shear, and it becomes nearly independent of shear as shear becomes too strong. This asymptotic behaviour at weak and strong shear has implications for magnetic activity cycles of stars in recent observations. Our study thus essentially generalizes the standard αΩ (or α2Ω) dynamo as also the α effect is affected by shear and the modelled random flow has a finite memory.
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Song, Jingjing, Jun Wang, Xiangao Xia, Runsheng Lin, Yi Wang, Meng Zhou, and Disong Fu. "Characterization of Urban Heat Islands Using City Lights: Insights from MODIS and VIIRS DNB Observations." Remote Sensing 13, no. 16 (August 11, 2021): 3180. http://dx.doi.org/10.3390/rs13163180.
Повний текст джерелаАнотація:
An urban heat island (UHI) is a phenomenon whereby the temperature in an urban area is significantly warmer than it a rural area. To further advance the characterization and understanding of UHIs within urban areas, nighttime light measured by the Day/Night Band (DNB) onboard the Visible Infrared Imaging Radiometer Suite (VIIRS) and the land surface temperature (LST) data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) combined with principal component analysis (PCA) are used here. Beijing (highly developed) and Pyongyang (less developed) are selected as the two case studies. Linear correlation analysis is first used, with higher correlations being found between DNB and LST data at nighttime than between population and LST data for both cities, although none of the correlation coefficients are particularly high because of noise. Principal component analysis (PCA), a method that can remove random noise, is used to extract more useful information. Two types of PCA are conducted, focusing on spatial (S) and temporal (T) patterns. The results of the S-mode PCA reveal that the typical temporal variation is a seasonal cycle for both LST and DNB data in Beijing and Pyongyang. Furthermore, there are monthly cycles for DNB data related to the moon phase in two cities. The T-mode PCA results show important spatial information, while the spatial pattern of the first mode explains over 50% of the variation. This study is among the first to demonstrate the advantages of using urban light to study the spatial variation of urban heat, especially for nighttime urban temperatures measured from space, at the street and neighborhood scales.
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Lee, Thomas Y. S. "Analysis of Single Buffer Random Polling System With State-Dependent Input Process and Server/Station Breakdowns." International Journal of Operations Research and Information Systems 9, no. 1 (January 2018): 22–50. http://dx.doi.org/10.4018/ijoris.2018010102.
Повний текст джерелаАнотація:
Models and analytical techniques are developed to evaluate the performance of two variations of single buffers (conventional and buffer relaxation system) multiple queues system. In the conventional system, each queue can have at most one customer at any time and newly arriving customers find the buffer full are lost. In the buffer relaxation system, the queue being served may have two customers, while each of the other queues may have at most one customer. Thomas Y.S. Lee developed a state-dependent non-linear model of uncertainty for analyzing a random polling system with server breakdown/repair, multi-phase service, correlated input processes, and single buffers. The state-dependent non-linear model of uncertainty introduced in this paper allows us to incorporate correlated arrival processes where the customer arrival rate depends on the location of the server and/or the server's mode of operation into the polling model. The author allows the possibility that the server is unreliable. Specifically, when the server visits a queue, Lee assumes that the system is subject to two types of failures: queue-dependent, and general. General failures are observed upon server arrival at a queue. But there are two possibilities that a queue-dependent breakdown (if occurs) can be observed; (i) is observed immediately when it occurs and (ii) is observed only at the end of the current service. In both cases, a repair process is initiated immediately after the queue-dependent breakdown is observed. The author's model allows the possibility of the server breakdowns/repair process to be non-stationary in the number of breakdowns/repairs to reflect that breakdowns/repairs or customer processing may be progressively easier or harder, or that they follow a more general learning curve. Thomas Y.S. Lee will show that his model encompasses a variety of examples. He was able to perform both transient and steady state analysis. The steady state analysis allows us to compute several performance measures including the average customer waiting time, loss probability, throughput and mean cycle time.
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Stewart, Jane E., Kalyn A. Thomas, Christopher B. Lawrence, Ha Dang, Barry M. Pryor, L. M. (Pete) Timmer, and Tobin L. Peever. "Signatures of Recombination in Clonal Lineages of the Citrus Brown Spot Pathogen, Alternaria alternata sensu lato." Phytopathology® 103, no. 7 (July 2013): 741–49. http://dx.doi.org/10.1094/phyto-08-12-0211-r.
Повний текст джерелаАнотація:
Most Alternaria spp. are considered asexual but recent molecular evolution analyses of Alternaria mating-type genes show that the mating locus is under strong purifying selection, indicating a possible role in sexual reproduction. The objective of this study was to determine the mode of reproduction of an Alternaria alternata sensu lato population causing citrus brown spot in central Florida. Mating type of each isolate was determined, and isolates were sequenced at six putatively unlinked loci. Three genetically distinct subpopulations (SH1, SH4A, and SH4B) were identified using network and Bayesian population structure analyses. Results demonstrate that most subpopulations of A. alternata associated with citrus are clonal but some have the ability to extensively recombine through a cryptic sexual cycle or parasexual cycle. Although isolates were sampled in close physical proximity (≈2,500-m2 area), we were able to reject a random mating model using multilocus gametic disequilibrium tests for two subpopulations, SH1 and SH4B, suggesting that these subpopulations were predominantly asexual. However, three recombination events were identified in SH1 and SH4B and localized to individuals of opposite mating type, possibly indicating meiotic recombination. In contrast, in the third subpopulation (SH4A), where only one mating type was present, extensive reticulation was evident in network analyses, and multilocus gametic disequilibrium tests were consistent with recombination. Recombination among isolates of the same mating type suggests that a nonmeiotic mechanism of recombination such as the parasexual cycle may be operating in this subpopulation. The level of gene flow detected among subpopulations does not appear to be sufficient to prevent differentiation, and perhaps future speciation, of these A. alternata subpopulations.
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Tanuja*, P. S. L., and Mrs K. Prasanthi. "Reduction of Test Data with Hybrid Test Points." International Journal of Innovative Technology and Exploring Engineering 9, no. 3 (January 30, 2020): 2535–38. http://dx.doi.org/10.35940/ijitee.c7969.019320.
Повний текст джерелаАнотація:
ATPG vectors for a combinational circuit exhibit correlations among the bits of a test vector. We propose a BIST circuit design methodology using spectral methods which utilizes the correlation information. This circuit serves dual purposes. It generates BIST vectors that are similar to the ATPG vectors with higher test coverage as compared to random and weighted random vectors. The same circuit can also function as a test data de-compressor for compressed ATPG vectors applied from an external tester. Logic built-in self-test (LBIST) is now increasingly used with on-chip test compression as a complementary solution for in-system test, where high quality, low power, low silicon area, and most importantly short test application time are key factors affecting ICs targeted for safety-critical systems. Test points, common in LBIST-ready designs, can help to reduce test time and the overall silicon overhead so that one can get desired test coverage with the minimal number of patterns. Typically, LBIST test points are dysfunctional when enabled in an ATPG-based test compression mode. Similarly, test points used to reduce ATPG pattern counts cannot guarantee desired random testability. We present a hybrid test point technology designed to reduce deterministic pattern counts and to improve fault detection likelihood by means of the same minimal set of test points. The hybrid test points are subsequently deployed in a scan-based LBIST scheme addressing stringent test requirements of certain application domains such as the automotive electronics market. These requirements, largely driven by safety standards, are met by significantly reducing test application time while preserving the high fault coverage. The new scheme is a combination of pseudorandom test patterns delivered in a test-per-clock fashion through conventional scan chains and per cycle-driven hybrid observation test points that capture faulty effects every shift cycle into dedicated scan chains. We also exhibit test data compression capabilities of the proposed BIST architecture. This architecture provides a maximum test data compression exceeding and a proportional test time reduction for serial interface reseeding.
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L’Heureux, Ivan. "Diagenetic Self-Organization and Stochastic Resonance in a Model of Limestone-Marl Sequences." Geofluids 2018 (2018): 1–18. http://dx.doi.org/10.1155/2018/4968315.
Повний текст джерелаАнотація:
Banded patterns in limestone-marl sequences (“rhythmites”) form widespread sediments typical of shallow marine environments. They are characterized by alternations of limestone-rich layers and softer calcareous-clayey material (marl) extending over hundreds of meters with a thickness of a few tens of meters. The banded sequences are usually thought to result from systematic variations in the external environment, but the pattern may be distorted by diagenetic nonlinear processes. Here, we present a reactive-transport model for the formation of banded patterns in such a system. The model exhibits interesting features typical of nonlinear dynamical systems: (i) the existence of self-organized oscillating patterns between a calcite-rich mode (“limestone”) and a calcite-poor one (“marl”) for fixed environmental conditions and (ii) bistability between these two modes. We then illustrate the phenomena of stochastic resonance, whereby the multistable system is driven by a small external periodic signal (the 100,000 years’ Milankovitch cycle comes to mind) that is too weak to generate oscillations between the states on its own. In the presence of random fluctuations, however, the system generates transitions between the calcite-rich and calcite-poor states in statistical synchrony with the external forcing. The signal-to-noise ratio exhibits many maxima as the noise strength is varied. Hence, this amplification effect is maximized for specific values of the noise strength.
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Zhang, Chun-Yi, Tian Sun, Wang Ai-Hua, Hui-Zhe Jing, Bao-Sheng Liu, and Cheng-Wei Li. "Reliability analysis of blade fatigue life based on fuzzy intelligent multiple extremum response surface method." Filomat 32, no. 5 (2018): 1897–907. http://dx.doi.org/10.2298/fil1805897z.
Повний текст джерелаАнотація:
In order to more reasonable analyze the dynamic reliability of aero-engine blade with coupling failure mode. A fuzzy intelligent multiple extremum response surface method (FIMERSM) was proposed. Considering the coupling effect of temperature load and centrifugal load, the maximum stress point, the maximum strain point and the minimum life point on blade were found by deterministic analysis. Then, the density of blade, rotor speed, elastic modulus, blade-tip temperature, blade-root temperature, fatigue strength coefficient, fatigue strength exponent, fatigue ductility coefficient, fatigue ductility exponent, blade width, blade thickness, blade torsion angle, and blade height as input random variables. By using Latin hypercube sampling technique, the sample values of the input random variables were acquired and finite element basic equation was calculated for each samples which obtained the corresponding dynamic output response of their stress, strain, and low cycle fatigue life within the analysis time domain. By taking the entire maximum values of the dynamic output response in the analysis time domain as new output response, the fuzzy intelligent multiple extremum response surface function (FIMERSF) was established. Finally, the dynamic reliability of the blade structure were obtained by using the Monte Carlo method (MCM) large amount linkage sampling of the input random variables and take it into the FIMERSF to calculate the output response. The results imply that the comprehensive reliability of blade is 99.46%. Through the comparison of MCM, Multiple extremum response surface method (MERSM) and FIMERSM, the computational results show that the FIMERSM has high computational precision and computational efficiency.
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Tulich, Stefan N., David A. Randall, and Brian E. Mapes. "Vertical-Mode and Cloud Decomposition of Large-Scale Convectively Coupled Gravity Waves in a Two-Dimensional Cloud-Resolving Model." Journal of the Atmospheric Sciences 64, no. 4 (April 1, 2007): 1210–29. http://dx.doi.org/10.1175/jas3884.1.
Повний текст джерелаАнотація:
Abstract This paper describes an analysis of large-scale [O(1000 km)] convectively coupled gravity waves simulated using a two-dimensional cloud-resolving model. The waves develop spontaneously under uniform radiative cooling and approximately zero-mean-flow conditions, with wavenumber 2 of the domain appearing most prominently and right-moving components dominating over left-moving components for random reasons. The analysis discretizes the model output in two ways. First, a vertical-mode transform projects profiles of winds, temperature, and heating onto the vertical modes of the model’s base-state atmosphere. Second, a cloud-partitioning algorithm sorts sufficiently cloudy grid columns into three categories: shallow convective, deep convective, and stratiform anvil. Results show that much of the tilted structures of the waves can be captured by just two main vertical spectral “bands,” each consisting of a pair of vertical modes. The “slow” modes have propagation speeds of 16 and 18 m s−1 (and roughly a full-wavelength vertical structure through the troposphere), while the “fast” modes have speeds of 35 and 45 m s−1 (and roughly a half-wavelength structure). Deep convection anomalies in the waves are more or less in phase with the low-level cold temperature anomalies of the slow modes and in quadrature with those of the fast modes. Owing to the characteristic life cycle of deep convective cloud systems, shallow convective heating peaks ∼2 h prior to maximum deep convective heating, while stratiform heating peaks ∼3 h after. The onset of deep convection in the waves is preceded by a gradual deepening of shallow convection lasting a period of many hours. Results of this study are in broad agreement with simple two-mode models of unstable large-scale wave growth, under the name “stratiform instability.” Differences here are that 1) the key dynamical modes have speeds in the range 16–18 m s−1, rather than 23–25 m s−1 (owing to a shallower depth of imposed radiative cooling), and 2) deep convective heating, as well as stratiform heating, is essential for the generation and maintenance of the slow modes.
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Vilain, Sébastien, Yun Luo, Michael B. Hildreth, and Volker S. Brözel. "Analysis of the Life Cycle of the Soil Saprophyte Bacillus cereus in Liquid Soil Extract and in Soil." Applied and Environmental Microbiology 72, no. 7 (July 2006): 4970–77. http://dx.doi.org/10.1128/aem.03076-05.
Повний текст джерелаАнотація:
ABSTRACT Bacillus is commonly isolated from soils, with organisms of Bacillus cereus sensu lato being prevalent. Knowledge of the ecology of B. cereus and other Bacillus species in soil is far from complete. While the older literature favors a model of growth on soil-associated organic matter, the current paradigm is that B. cereus sensu lato germinates and grows in association with animals or plants, resulting in either symbiotic or pathogenic interactions. An in terra approach to study soil-associated bacteria is described, using filter-sterilized soil-extracted soluble organic matter (SESOM) and artificial soil microcosms (ASM) saturated with SESOM. B. cereus ATCC 14579 displayed a life cycle, with the ability to germinate, grow, and subsequently sporulate in both the liquid SESOM extract and in ASM inserted into wells in agar medium. Cells grew in liquid SESOM without separating, forming multicellular structures that coalesced to form clumps and encasing the ensuing spores in an extracellular matrix. Bacillus was able to translocate from the point of inoculation through soil microcosms as shown by the emergence of outgrowths on the surrounding agar surface. Microscopic inspection revealed bundles of parallel chains inside the soil. The motility inhibitor l-ethionine failed to suppress outgrowth, ruling out translocation by a flagellar-mediated mechanism such as swimming or swarming. Bacillus subtilis subsp. subtilis Marburg and four Bacillus isolates taken at random from soils also displayed a life cycle in SESOM and ASM and were all able to translocate through ASM, even in presence of l-ethionine. These data indicate that B. cereus is a saprophytic bacterium that is able to grow in soil and furthermore that it is adapted to translocate by employing a multicellular mode of growth.
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KIRUBADURAI, B., K. KANAGARAJA, and G. JEGADEESWARI. "Analysis of Knocking Characteristic in Dual Fuel Engine - the Effects on Diethyl Ether." INCAS BULLETIN 13, no. 2 (June 4, 2021): 83–90. http://dx.doi.org/10.13111/2066-8201.2021.13.2.9.
Повний текст джерелаАнотація:
In Diesel engines, where fuel is pumped into highly compressed air towards the end of the compression cycle, knocking is more or less unavoidable. By this time there is already a quantity of fuel in the combustion chamber which will first burn in areas of higher oxygen density before the full charge is combusted. The sudden rise in pressure and temperature produces the distinctive 'knock' or 'clatter' diesel, some of which must be allowed in engine design. The aim of knock control strategies is to try to maximize the trade-off between protecting the engine from damaging knock incidents, and optimizing the output torque of the engine. Knock events are a random process and independent. Knock controllers can't be programmed in a deterministic model. Due to the random nature of arriving knock events, a single time history simulation or experiment of knock control methods cannot provide a repeatable measurement of the controller efficiency. The desired trade-off must therefore be achieved in a stochastic context that could provide an appropriate environment for designing and evaluating the output of various knock control strategies with rigorous statistical properties. Clutching characteristics of a dual fuel diesel engine with direct injection of diesel and a liquid petroleum product in dual fuel mode. The engine is tested for knock reduction by adding Diethyl ether in to the diesel along with Liquid petroleum product. Variation of knocking was plotted with respect to different parameters and the result booted as knocking is minimized by the addition of diethyl ether.
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Bai, Bing, Qing Hua Zhang, and Qiao Li. "Reliability Assessment for the Balanced Cantilever Construction Phases of Super Long-Span Cable-Stayed Bridges with Steel Box Girder." Applied Mechanics and Materials 578-579 (July 2014): 1542–50. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.1542.
Повний текст джерелаАнотація:
Balanced cantilever construction phases are of great importance for the total life cycle processes of super long-span cable-stayed bridges. For assessment purpose, a systematic study on the reliability evaluation of these phases is carried out. Taking Sutong bridge as the sample structure studied, a series of load and resistance models are then established on the basis of field measurement. Using all these achievements, a typical phase of girder segment 6# lifting is chosen for reliability evaluation. Results of the analysis show that the established models are quite representative and reflect actual random nature perfectly. Furthermore, compared with pylon and stay cables the stiffening girder seems more likely to fail in accordance with reliability index. The major failure mode of it in terms of present analysis is the stability failure due to the action of bending and axial load. Nonetheless, the components on the whole are still in a high level of reliability, which can guarantee the proceeding of construction with efficiency.
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Yang, Guisong, Zhiwei Peng, and Xingyu He. "Data Collection Based on Opportunistic Node Connections in Wireless Sensor Networks." Sensors 18, no. 11 (October 30, 2018): 3697. http://dx.doi.org/10.3390/s18113697.
Повний текст джерелаАнотація:
The working–sleeping cycle strategy used for sensor nodes with limited power supply in wireless sensor networks can effectively save their energy, but also causes opportunistic node connections due to the intermittent communication mode, which can affect the reliability of data transmission. To address this problem, a data collection scheme based on opportunistic node connections is proposed to achieve efficient data collection in a network with a mobile sink. In this scheme, the mobile sink first broadcasts a tag message to start a data collection period, and all nodes that receive this message will use the probe message to forward their own source information to the mobile sink. On receiving these probe messages, the mobile sink then constructs an opportunistic connection random graph by analyzing the source information included in them, and calculates the optimal path from itself to each node in this random graph, therefore a spanning tree could be generated with the mobile sink play as the root node, finally, it broadcasts this spanning tree so that each node could obtain an optimal path from itself to the mobile sink to forward the sensing data. In addition, a routing protocol that adapts to different nodes operating statuses is proposed to improve the reliability of data transmission. Simulation results show that the proposed scheme works better concerning the packet delivery rate, energy consumption and network lifetime.
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Kouvelioti, R., N. Kurgan, B. Falk, W. E. Ward, A. R. Josse, and P. Klentrou. "Response of Sclerostin and Bone Turnover Markers to High Intensity Interval Exercise in Young Women: Does Impact Matter?" BioMed Research International 2018 (November 1, 2018): 1–8. http://dx.doi.org/10.1155/2018/4864952.
Повний текст джерелаАнотація:
This study examined potential exercise-induced changes in sclerostin and in bone turnover markers in young women following two modes of high intensity interval exercise that involve impact (running) or no-impact (cycling). Healthy, recreationally active, females (n=20; 22.5±2.7 years) performed two exercise trials in random order: high intensity interval running (HIIR) on a treadmill and high intensity interval cycling (HIIC) on a cycle ergometer. Trials consisted of eight 1 min running or cycling intervals at ≥90% of maximal heart rate, separated by 1 min passive recovery intervals. Blood samples were collected at rest (pre-exercise) and 5 min, 1h, 24h, and 48h following each exercise trial. Serum was analyzed for sclerostin, cross linked telopeptide of type I collagen (CTXI), and procollagen type I amino-terminal propeptide (PINP). A significant time effect was found for sclerostin, which increased from pre-exercise to 5 min after exercise in both trials (100.2 to 131.6 pg/ml in HIIR; 102.3 to 135.8 pg/ml in HIIC, p<0.001) and returned to baseline levels by 1h, with no difference between exercise modes and no exercise mode-by-time interaction. CTXI did not significantly change following either trial. PINP showed an overall time effect following HIIR, but none of the post hoc pairwise comparisons were statistically significant. In young women, a single bout of high intensity exercise induces an increase in serum sclerostin, irrespective of exercise mode (impact versus no-impact), but this response is not accompanied by a response in either bone formation or resorption markers.
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Hamedi, Khashayar, Shahrbanoo Sadeghi, Saeed Esfandi, Mahdi Azimian, and Hessam Golmohamadi. "Eco-Emission Analysis of Multi-Carrier Microgrid Integrated with Compressed Air and Power-to-Gas Energy Storage Technologies." Sustainability 13, no. 9 (April 22, 2021): 4681. http://dx.doi.org/10.3390/su13094681.
Повний текст джерелаАнотація:
Growing concerns about global greenhouse gas emissions have led power systems to utilize clean and highly efficient resources. In the meantime, renewable energy plays a vital role in energy prospects worldwide. However, the random nature of these resources has increased the demand for energy storage systems. On the other hand, due to the higher efficiency of multi-energy systems compared to single-energy systems, the development of such systems, which are based on different types of energy carriers, will be more attractive for the utilities. Thus, this paper represents a multi-objective assessment for the operation of a multi-carrier microgrid (MCMG) in the presence of high-efficiency technologies comprising compressed air energy storage (CAES) and power-to-gas (P2G) systems. The objective of the model is to minimize the operation cost and environmental pollution. CAES has a simple-cycle mode operation besides the charging and discharging modes to provide more flexibility in the system. Furthermore, the demand response program is employed in the model to mitigate the peaks. The proposed system participates in both electricity and gas markets to supply the energy requirements. The weighted sum approach and fuzzy-based decision-making are employed to compromise the optimum solutions for conflicting objective functions. The multi-objective model is examined on a sample system, and the results for different cases are discussed. The results show that coupling CAES and P2G systems mitigate the wind power curtailment and minimize the cost and pollution up to 14.2% and 9.6%, respectively.
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Codron, Francis. "Relation between Annular Modes and the Mean State: Southern Hemisphere Summer." Journal of Climate 18, no. 2 (January 15, 2005): 320–30. http://dx.doi.org/10.1175/jcli-3255.1.
Повний текст джерелаАнотація:
Abstract The annular modes emerge as the leading mode of extratropical month-to-month climate variability in both hemispheres. Here the influence of the background state on the structure and dynamics of the Southern Hemisphere annular mode (SAM) during the austral summer when the climatology is characterized by a single, well-defined, eddy-driven jet is studied. Subsets of the climatology are constructed for early and late summer, and for contrasting polarities of the ENSO cycle. The analysis is based both on observations and on perpetual-state GCM experiments. The main differences between the subsets involve variations of the latitude of the mean jet. It is found that in all the cases, the SAM is characterized by latitudinal shifts of the jet about its mean position, reinforced by a positive momentum flux feedback from baroclinic waves. This result is consistent with previous studies of the dynamics of the zonally averaged circulation but is found here to hold over all longitudes and for different positions of the mean jet. The low frequency eddies exert a weaker negative feedback upon the mean flow, with a less zonally symmetric structure. The strong differences in the amplitude of the SAM among the various climatologies seem to be determined by a combination of 1) the variance of the “random” forcing by transient eddies and 2) the strength of the positive feedback component of this forcing. The latter mechanism increases the variance at low frequencies only and lengthens the decorrelation time of zonal-mean zonal wind anomalies. It tends to become stronger when the mean jet moves equatorward.
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Swank, Ann M., Alissa Moore, Daniel C. Funk, Lynne Steinel, Robert J. Robertson, and John T. Manire. "Evaluation of Anticipation Bias for RPE during Progressive Exercise Testing." Perceptual and Motor Skills 100, no. 3 (June 2005): 841–50. http://dx.doi.org/10.2466/pms.100.3.841-850.
Повний текст джерелаАнотація:
This study evaluated a possible anticipation bias when ratings of perceived exertion (RPE) were obtained during submaximal progressive exercise testing. Perceptual estimates were obtained using the CR-10 category-ratio scale. 13 subjects, 7 men and 6 women ( M age = 26.8 ± 6.4 yr., height = 2.7 ± .17 m, weight = 73.0 ± 18.2 kg, VO2 peak = 46.7 ± 5.6 ml · kg−1 · min−1 for men and 47.8 ± 7.3 ml · kg−1 · min.−1 for women) recruited from the university student population participated. Each subject underwent two submaximal progressive exercise tests separated by at least 48 hr. using the cycle as test mode and the YMCA protocol. Power outputs established during the first test were presented in random order during the second test. Differentiated RPE for the Peripheral, Respiratory-Metabolic, and the undifferentiated signals, and heart rate, were measured during the last 15 sec. of each of the four stages of exercise. In comparing responses between the two tests, significant differences were observed for both heart rate and the Respiratory-Metabolic signal during power output 4, using repeated-measures analysis of variance. However, a 95% limit of agreement test was significant only for heart rate as the 95% confidence interval for the Respiratory-Metabolic signal overlapped zero and thus was not significantly different. No significant differences were found for the undifferentiated or peripheral signals between the two tests. Results indicate that both undifferentiated and differentiated RPE are given without significant anticipation bias during submaximal progressive cycle exercise.
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MÜLLER-GRAF, C. D. M., P. DURAND, C. FELIU, J. P. HUGOT, C. J. O'CALLAGHAN, F. RENAUD, F. SANTALLA, and S. MORAND. "Epidemiology and genetic variability of two species of nematodes (Heligmosomoides polygyrus and Syphacia stroma) of Apodemus spp." Parasitology 118, no. 4 (April 1999): 425–32. http://dx.doi.org/10.1017/s003118209800393x.
Повний текст джерелаАнотація:
The epidemiology and genetic variability of 2 parasitic nematodes Heligmosomoides polygyrus and Syphacia stroma of Apodemus spp. were investigated. Both are parasites of the same host, exhibit a direct life-cycle and are dioecious. However, H. polygyrus has a diploid and S. stroma a haplodiploid mode of reproduction. Haplodiploidy may lead to a more female biased sex ratio and reduced genetic variability. Levels of genetic diversity were analysed using both isoenzyme electrophoresis and RAPDs (random amplified polymorphic DNA). Both parasites showed a female biased sex ratio with a stronger bias for the haplodiploid parasite. Results showed significantly fewer genetic polymorphisms as measured by RAPDs for the haplodiploid parasite S. stroma in comparison with H. polygyrus. Despite the observed female biased sex ratio this could not be explained by a significant amount of inbreeding. Heterozygote deficiency for individual allozyme loci – which could indicate inbreeding – was not found in either parasite species. Other features of the particular life-history of these species are likely to have an impact on the sex ratio and genetic variability too.
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Liu, Wei, Yunhua Li, and Dong Li. "A coordinated control law for inlet/outlet independent regulation of electro-hydraulic speed control system under sustained negative load." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 9 (January 16, 2020): 1689–705. http://dx.doi.org/10.1177/0954406219899691.
Повний текст джерелаАнотація:
Negative load operation is an inevitable operating condition for a completed task cycle of electro-hydraulic speed control system. In this working condition, to coordinate both tracking control and speed smooth regulation is necessary for avoiding stall. In this paper, a nonlinear coordinated control law aiming at independent regulation of inlet/outlet oil of valve-controlled electro-hydraulic speed system under sustained negative load is proposed. The overall control system can be divided into position tracking control subsystem and speed smooth control subsystem according to the function of the system operation. First, the coordinated control strategy is designed according to the requirements of speed tracking and speed smoothing. Then, for the coupling control problem existed in the system, a novel control law based on objective acceleration planning and expected back-pressure planning is presented. Furthermore, specified on the problem of uncertain random disturbance in practical applications, the extended state observer is designed, extending the summation of uncertain stochastic disturbance under sustained negative load into a new state variable. Finally, addressing the coordinated control strategy with expected back-pressure planning, we designed nonlinear decoupling control laws by using backstepping sliding mode robust control and backstepping sliding mode control based on extended state observer, respectively. The results of simulation and experiment show that the proposed nonlinear coordinated control strategy can provide the excellent coordination and robust performance for tracking control and speed smooth regulation.
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Micabalo, Kingie G., Jesszon B. Cano, Ryan D. Montilla, Arsenio Robert N. Tan, and June Ace P. Navarro. "Complexity and Significance: A Sequential Analysis on the Conduct of Research." Asian Journal of Managerial Science 9, no. 2 (November 5, 2020): 31–39. http://dx.doi.org/10.51983/ajms-2020.9.2.1640.
Повний текст джерелаАнотація:
Research is a mission for trust with the assistance of study, acknowledgment, association, and preliminaries in the journey for information through the goal and proficient methodology to discover answers for an issue. The examination decides and breaks down the degree of appraisal seen by the understudies as far as the complexity and significance of the research. The examination respondents were the 252 understudies from Marketing and Human Resource Management courses utilizing the descriptive survey method as a research instrument on a simple random sampling. Frequency and simple percentage, and Mode were used to summarize, separate, and unravel the information. The discovery uncovered that understudies gigantically experienced complexities recorded in composing the proposition, leading the exploration, and managing the research paper. The study concludes that research is a critical portion of understudies’ learning cycle and incredibly adds to making College undertaking more compelling in imparting long lasting learning. Departmental Research courses and workshops are to be practiced to hone understudies’ degree of commitment and mindfulness concerning Research. Emphasis on the significance of research among understudies is a thing to be perceived to persuade them to seek after research, notwithstanding the struggles that they may experience.
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Leroux, Stephanie, Thierry Penduff, Laurent Bessières, Jean-Marc Molines, Jean-Michel Brankart, Guillaume Sérazin, Bernard Barnier, and Laurent Terray. "Intrinsic and Atmospherically Forced Variability of the AMOC: Insights from a Large-Ensemble Ocean Hindcast." Journal of Climate 31, no. 3 (January 22, 2018): 1183–203. http://dx.doi.org/10.1175/jcli-d-17-0168.1.
Повний текст джерелаАнотація:
Abstract This study investigates the origin and features of interannual–decadal Atlantic meridional overturning circulation (AMOC) variability from several ocean simulations, including a large (50 member) ensemble of global, eddy-permitting (1/4°) ocean–sea ice hindcasts. After an initial stochastic perturbation, each member is driven by the same realistic atmospheric forcing over 1960–2015. The magnitude, spatiotemporal scales, and patterns of both the atmospherically forced and intrinsic–chaotic interannual AMOC variability are then characterized from the ensemble mean and ensemble spread, respectively. The analysis of the ensemble-mean variability shows that the AMOC fluctuations north of 40°N are largely driven by the atmospheric variability, which forces meridionally coherent fluctuations reaching decadal time scales. The amplitude of the intrinsic interannual AMOC variability never exceeds the atmospherically forced contribution in the Atlantic basin, but it reaches up to 100% of the latter around 35°S and 60% in the Northern Hemisphere midlatitudes. The intrinsic AMOC variability exhibits a large-scale meridional coherence, especially south of 25°N. An EOF analysis over the basin shows two large-scale leading modes that together explain 60% of the interannual intrinsic variability. The first mode is likely excited by intrinsic oceanic processes at the southern end of the basin and affects latitudes up to 40°N; the second mode is mostly restricted to, and excited within, the Northern Hemisphere midlatitudes. These features of the intrinsic, chaotic variability (intensity, patterns, and random phase) are barely sensitive to the atmospheric evolution, and they strongly resemble the “pure intrinsic” interannual AMOC variability that emerges in climatological simulations under repeated seasonal-cycle forcing. These results raise questions about the attribution of observed and simulated AMOC signals and about the possible impact of intrinsic signals on the atmosphere.
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Wenbing, Shui, and Xinrui Chen. "Joint Ordering and Selling Policy for Storable Agricultural Products in Contract Farming." Scientific Programming 2022 (February 15, 2022): 1–11. http://dx.doi.org/10.1155/2022/6994700.
Повний текст джерелаАнотація:
With the farming mode widely promoted in many countries around the world, agricultural enterprises need to face risks from both supply and sales at the same time. Especially for storable agricultural products, it is also necessary to consider the potential profits and losses brought about by the sales of multi-period. This paper establishes a joint ordering and selling decision model under multiperiod random supply and demand. The model takes the maximum expected profit of agricultural enterprises as the goal, considers the constraints of production capacity and the risk preference coefficient of shortage, and makes decisions on the order and sales quantity in each cycle. The feasibility of the model was verified by taking China Yunnan Pu’er tea as a specific example. Finally, through numerical examples, the influence of important parameters on the joint ordering and selling strategy is as follows: order cost is the main factor affecting the order quantity. When the order cost increases to a certain level, the solving algorithm will make a decision that would rather be out of stock than to order. With the increase in selling price, inventory holding cost, and shortage cost, there will be an increasing trend of the sales quantity allocated to this period. Compared with other parameters, selling price and inventory holding cost have a more remarkable impact on sales quantity. In addition, enterprises can increase their expected profits of storable agricultural products by controlling the inventory holding cost, appropriately reducing the risk preference coefficient, and increasing the level of the selling price.
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Gregor, Luke, Schalk Kok, and Pedro M. S. Monteiro. "Interannual drivers of the seasonal cycle of CO<sub>2</sub> in the Southern Ocean." Biogeosciences 15, no. 8 (April 19, 2018): 2361–78. http://dx.doi.org/10.5194/bg-15-2361-2018.
Повний текст джерелаАнотація:
Abstract. Resolving and understanding the drivers of variability of CO2 in the Southern Ocean and its potential climate feedback is one of the major scientific challenges of the ocean-climate community. Here we use a regional approach on empirical estimates of pCO2 to understand the role that seasonal variability has in long-term CO2 changes in the Southern Ocean. Machine learning has become the preferred empirical modelling tool to interpolate time- and location-restricted ship measurements of pCO2. In this study we use an ensemble of three machine-learning products: support vector regression (SVR) and random forest regression (RFR) from Gregor et al. (2017), and the self-organising-map feed-forward neural network (SOM-FFN) method from Landschützer et al. (2016). The interpolated estimates of ΔpCO2 are separated into nine regions in the Southern Ocean defined by basin (Indian, Pacific, and Atlantic) and biomes (as defined by Fay and McKinley, 2014a). The regional approach shows that, while there is good agreement in the overall trend of the products, there are periods and regions where the confidence in estimated ΔpCO2 is low due to disagreement between the products. The regional breakdown of the data highlighted the seasonal decoupling of the modes for summer and winter interannual variability. Winter interannual variability had a longer mode of variability compared to summer, which varied on a 4–6-year timescale. We separate the analysis of the ΔpCO2 and its drivers into summer and winter. We find that understanding the variability of ΔpCO2 and its drivers on shorter timescales is critical to resolving the long-term variability of ΔpCO2. Results show that ΔpCO2 is rarely driven by thermodynamics during winter, but rather by mixing and stratification due to the stronger correlation of ΔpCO2 variability with mixed layer depth. Summer pCO2 variability is consistent with chlorophyll a variability, where higher concentrations of chlorophyll a correspond with lower pCO2 concentrations. In regions of low chlorophyll a concentrations, wind stress and sea surface temperature emerged as stronger drivers of ΔpCO2. In summary we propose that sub-decadal variability is explained by summer drivers, while winter variability contributes to the long-term changes associated with the SAM. This approach is a useful framework to assess the drivers of ΔpCO2 but would greatly benefit from improved estimates of ΔpCO2 and a longer time series.
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Miao, Bing Rong, Shou Ne Xiao, Ding Chang Jin, and Guang Wu Yang. "Research of Fatigue Life Simulations Applied to Large Complex Structure." Key Engineering Materials 353-358 (September 2007): 1017–20. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1017.
Повний текст джерелаАнотація:
In structural design for safety and durability, the primary concern is to reduce structural fatigue damages due to random dynamic loadings during the service life of locomotive vehicle system. Rolling stocks is facing new sever safety problems, such as bogie frame structure components fracture and safety-based design optimization to durability of locomotive. The objective of the current research is to find the most efficient approach to predict structure safety with Multi-Body Simulation (MBS) and Finite Element Method (FEM). The method is implemented to evaluate bogie frame fatigue damages under dynamic stochastic loadings. The time varying boundary conditions and dynamic load history acting on the large structure can be evaluated by applying the Multi-body Simulation technique in software SIMPACK. Stress/strain analysis technology with software ANSYS yields the danger stresses in the critical locations of the structure depending on the unite loads. And modal analysis is used to determine frequencies and mode shapes of structure. Based on these danger stresses distribution and dynamic load time history, fatigue life can be estimated with Palmgren-Miner theory. The standard time history method involves stress or strain cycle counting, damage prediction, and finally life estimation in Software FE-Fatigue with factor of safety technology.
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Apryshkin, D. S., G. Sh Khazanovich, and V. О. Gutarevich. "Improving the maintenance program for passenger elevators based on simulation of their operating modes." Advanced Engineering Research 21, no. 2 (July 9, 2021): 171–83. http://dx.doi.org/10.23947/2687-1653-2021-21-2-171-183.
Повний текст джерелаАнотація:
Introduction. Elevators in residential and public buildings are the means of vertical transport. An elevator is one of the complex electromechanical devices of increased danger. Therefore, all stages of its life cycle are strictly limited by regulatory documents. The desired levels of safety and comfort are provided through the reasonable choice of the basic parameters and a constant maintenance of the system in good condition. The key factors that affect the implementation of regulatory requirements during the operation of the elevator installation are the quality of manufacturing of critical components, the level of real workload, taking into account the actual value of the spent resource, and the implemented maintenance program. Currently, when determining the maintenance schedule for elevators, such characteristics as the density of occupancy, the level of power loads, the actual operating time of the elevator and the counts of starts of the main drive are not taken into account. This study objective is the scientific rationale of the concept and methodology for developing the program of maintenance of specific elevator installations on the basis of studies of the level and mode of loading of load-bearing units. Materials and Methods. The use of simulation modeling techniques to assess the load level of power units of an elevator installation and its kinematic indicators under the action of numerous random impacts is validated in the paper. The development of an indicator that characterizes the complex mode of elevator operation, taking into account the joint influence of the level of resource development, net operating time, number of starts, and the power load of the nodes, required the application of an expert method. The final part of the research program is the formation of specific recommendations on the maintenance schedule of elevators. It is based on the ranking of particular indicators. Results. The performance feature of the elevator installation is that the service time of a customer is a function of many random variables. Mathematical models of the formation of force impacts are based on the representation of an electromechanical elevator as a dynamic one-degree-of-freedom system. Expressions for calculating the static tension of traction ropes and torques on the motor shaft are obtained. The problem of dynamics is solved. The loads whose values are the basis for performing simulation modeling of the operating modes of the elevator installation are determined. Discussion and Conclusions. Feasibility of the regulations for the maintenance of passenger elevators is an urgent task, the solution to which determines the level of safety and comfort of passengers. Currently, the standards for the design and operation of elevator installations do not link the frequency of maintenance programs with the level of load and the amount of resource development. The paper provides a general statement of the problem and a methodology for the formation of a complex factor of the equivalent load. Mathematical models are given for calculating the power and temporary loads of the elevator, taking into account the nature of numerous random impacts.
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Bracewell, RN. "Sunspot Number Series Envelope and Phase." Australian Journal of Physics 38, no. 6 (1985): 1009. http://dx.doi.org/10.1071/ph851009.
Повний текст джерелаАнотація:
The sunspot number series R( t) from 1700 to date is found to be representable by R( t) = I Jf' {Re( E( t) exp[i {wo t + ( t) I]) + U( t) 1 I, where Wo is the angular frequency corresponding to a period of 22 years, E(t) is the instantaneous envelope amplitude, (t) is the instantaneous phase of a complex time-varying analytic function, U(t) is an undulation of low amplitude and period about 30 (22-year) cycles and jy is a nonlinear operator whose main effect is to introduce a small amount of third harmonic (period about 7 years). The justification for the 22-year period is the known fact that the observable sunspot magnetic fields reverse polarity every 11 years or so at the time of sunspot minimum; the undulation has been demonstrated, and its period determined, in fossil records discovered by Williams; and the third harmonic is an expected consequence of minor nonlinearity in the dependence of the arbitrarily defined R( t) on the physical cause of sunspots. The algebraic representation is established by the Hilbert transform method of forming a complex analytic function as proposed by Gabor. The method reveals three obscuring features that may be alleviated as follows: use the alternating series R� (t) in which alternate II-year cycles take opposite signs, remove the third harmonic, and subtract the undulation. These justifiable steps remove artificial components, such as sum and difference frequencies, that are gratuitously and nonlinearly introduced by conventional Fourier analysis as applied to the rectified, or absolute, value of the 22-year oscillation. Then a complex envelope E( t) exp {i ( t)j can be discerned whose intrinsic behaviour can be studied to reveal statistics that bear on the physical origin of the solar cycle. The results favour a deep monochromatic oscillator whose influence is propagated to the observable surface via a time-varying medium. The r.m.s. value of the component of E(t) is 0�4 of the mean and the characteristic time is a century. Frequency analysis of the envelope does not support a 78-year period in the modulation noticed by Wolf. Both the statistical frequency distribution of the amplitude E( t) and its spectrum are subject to refinement by analysis of fossil solar records. The results do not favour the theory that the 22-year period is set by the natural frequency of a resonator with characteristic damping subject to random turbulent excitation. Also disfavoured is the theory of energy release at intervals determined by a relaxation process. Correlation has been found between the phase departure ~(t) from linear and envelope amplitude and attributed to propagation of the magnetic .cycles through a time-varying, such as a convecting, medium. A correlation not depending on Hilbert transform analysis is predicted between the reciprocal cycle length and envelope amplitude and found to� exist. Variability of the sunspot cycle length can be viewed as a Doppler shift due to propagation in a time-varying medium and the Wolf modulation then represents the concomitant intensity change. Agreement has been found between E(t) and '(t) but not explained. If the explanation is dispersion in the propagation of the assumed magnetic flux waves then there is a mode of oscillation. that has the characteristics required for the undulation U( t). Extra buoyancy possessed by the magnetic field of strong cycles accounts for the fast rise time of strong cycles.
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Shevchenko, O. L., A. D. Skorbun, and D. V. Charny. "SUBORDINATION OF FLUCTUATIONS OF GROUNDWATER LEVELS IN THE SOUTHERN BUG RIVER BASIN TO CLIMATE CHANGE." Odesa National University Herald. Geography and Geology 26, no. 2(39) (March 25, 2022): 175–94. http://dx.doi.org/10.18524/2303-9914.2021.2(39).246202.
Повний текст джерелаАнотація:
Problems Statementand Purpose. Prolonged flooding of territories, as well as modern drought, are only polar consequences of one, so far irreversible process – rising air temperature. And these events do not fit into normal cycles with high and low water levels. The aim of this work is to find evidence that the driving force or the main factorin changing the groundwater regime is the increase in air temperature and related meteorological events that affected the intra-annual redistribution of precipitation, groundwater recharge and surface runoff. Data & Methods. The degree of connection of GWL fluctuations with regime-forming factors was determined by statistical methods: wavelet analysis and multiplecorrelation analysis. Results. It is established that the depth of groundwater level (GWL), which was affected by the temperature in the upper part of the basin of the Southern Bug river, reaches 3.5–4.5 m after 1989. Signs of changes in the groundwater regime are manifested in the results of assessing the degree of violation of the statistical stability of a number of observations of GWL: the transition from random to hyperrandom data occurs in 1982–1983. According to the results of different statistical analysis over the past 40 years, the temperature has become dominant in terms of the impact on the regime of GWL 2.5–4.0 m. This refutes the traditional (based on observations of 1950–1970’s) statement that that the regime of groundwater with GWL 3.0–4.5 m is determined primarily by the regime of precipitation, and the active influence of surface air temperature (evaporation from GWL) in the forest-steppe zone extends only to a depth of 2.0–2.5 m. Extremes on the chronological graphs of the GWL regime and on integral curves are associated with abnormal changes in seasonal and monthly temperatures, which reflect the manifestations of global warming. It is likely that these anomalous events (primarily the transition to positive valuesof winter temperatures) cause changes in rhythm in the GWL mode (from 5–6 years cycles to 7–8 years ones and vice versa), which can be used for forecasting. From 1975 for GWL 0.5–2.0 m and from 1986 for GWL 2.5–4.0 m, due to the increase in the temperature of the cold period and increased GWL supply through infiltration, the GWL was raised. This process was accompanied by a 7–8 year cycle of changing. Deepening of the drought in the Southern Bug River Basin upper waters from 2003–2004, is manifested by the appearance and consolidation of 5–6 year cycle for smaller, and from 2011–2014 – for larger GWL, and by a significant weakening and disappearance of 7–8 year rhythms.