Картофелекопатель с ротационной сепарирующей поверхностью

2018 ◽  
Author(s):  
V.M. Alakin ◽  
G.S. Nikitin
Keyword(s):  
Performance Data ◽  
Pilot Studies ◽  
Research Results ◽  
Operating Modes ◽  
Analysis Of Results ◽  
Design Characteristics ◽  
And Performance ◽  
Definition Of

Приведены результаты исследований экспериментального картофелекопателя с ротационной сепарирующей поверхностью. Особое внимание уделяется обоснованию конструктивных параметров и определению рабочих характеристик нового сепарирующего устройства. На основе анализа результатов экспериментальных исследований определены наиболее оптимальные режимы работы экспериментального картофелекопателя.Research results of an experimental potato digger with rotational separating web are published in this article. Special attention is paid to definition of design characteristics and performance data of the new separating device. Admissible operating modes are defined on the basis of the analysis of results of pilot studies of the experimental potato digger.

A method for assessing resilience of high-speed EMUs considering a network-based system topology and performance data

2021 ◽  
pp. 1748006X2110045
Author(s):  
Shuai Lin ◽  
Limin Jia ◽  
Hengrun Zhang ◽  
Yanhui Wang
Keyword(s):  
System Performance ◽  
High Speed ◽  
Performance Data ◽  
Mathematical Expressions ◽  
Resilience Index ◽  
And Performance ◽  
Definition Of ◽  
Chinese Standard ◽  
Multiple Units ◽  
System Topology

The high complexity of the system topology and the uncertainty of threats necessitate the consideration of the resilience of high-speed electric multiple units (EMUs). This paper first gives a definition of high-speed EMU resilience. Then, the structure of a high-speed EMU is described in the form of a network to enable the application of network science for resilience evaluation based on corresponding mathematical expressions. Afterward, a measure of system performance (MSP) is constructed that considers the influence of the high-speed EMU topology and performance data. According to the definition of resilience of a high-speed EMU, a system resilience measurement (SRM) is proposed that comprehensively considers the degree and time of the change in system performance. The validity of our method is then illustrated by applying it to the system topology and performance data associated with the Chinese standard electric multiple units (CEMUs) that serve on high-speed railways in China. Experiments are reported to illustrate the concept of resilience and the procedure for its measurement and to present comparisons with an existing resilience index. Our results indicate that the SRM proposed here can capture the sensitivity of the response of high-speed EMUs to the disturbances, thereby supporting the optimal design and risk management.

Conditions for the Effective Use of Air Curtain on Objects of Agricultural Production

2020 ◽  
Vol 67 (1) ◽  
pp. 54-59
Author(s):  
Aleksey V. Kuz’michev ◽  
Stanislav S. Trunov ◽  
Dmitriy A. Tikhomirov
Keyword(s):  
Agricultural Production ◽  
Theoretical Models ◽  
Research Purpose ◽  
Engineering Practice ◽  
Physical Factors ◽  
Air Curtain ◽  
Operating Modes ◽  
Air Jets ◽  
Urgent Task ◽  
Design Characteristics

Creating and maintaining a microclimate in animal housing is an energy-intensive technological process that consumes up to 70 percent of the thermal energy consumed on cattle farms. Improving heating and ventilation systems aimed at reducing energy consumption is an urgent task. (Research purpose) The research purpose is to analyze the theoretical models for calculating air curtains and evaluate the possibility of their use for agricultural production facilities and to identify promising directions in the design solutions for thermal air curtains aimed at rural consumers. (Materials and methods) The article considers the theoretical justification and calculation of air curtains. The authors studied the physical model of interaction of air jets in openings, which serves as the basis for mathematical calculation of air curtains in engineering practice. The article describes the features of using the models for calculating air curtains for agricultural objects and the energy parameters of the curtains depending on the design characteristics and external environmental factors. (Results and discussion) The effect of the air curtain on the energy characteristics of the room has been studied. It was found that it is necessary to determine the type of air curtain that is optimally suitable for protecting the gate opening, with or without heating the air curtain. Authors have found that the engineering methods of calculation are based on different experimental data, which leads to a discrepancy in the results of evaluating the effectiveness of the designed curtain, overestimating its energy intensity and power. The calculation of heat curtains, operating modes should be carried out taking into account the variable effects of external physical factors, the equipment should correspond to a specific room. (Conclusions) The use of air curtains reduces or eliminates the penetration of external cold air into the room through the openings of external gates, requires a smaller volume of air supplied by the curtain, compared to the mass of the incoming air flow.

Positive Workplaces

2009 ◽  
pp. 578-588
Author(s):  
Fred Luthans ◽  
Carolyn M. Youssef
Keyword(s):  
Organizational Behavior ◽  
Psychological Capital ◽  
Future Research ◽  
Positive Organizational Behavior ◽  
Performance Impact ◽  
Research Directions ◽  
Future Research Directions ◽  
And Performance ◽  
Definition Of ◽  
Psychological Capacities

Over the years, both management practitioners and academics have generally assumed that positive workplaces lead to desired outcomes. Unlike psychology, considerable attention has also been devoted to the study of positive topics such as job satisfaction and organizational commitment. However, to place a scientifically based focus on the role that positivity may play in the development and performance of human resources, and largely stimulated by the positive psychology initiative, positive organizational behavior (POB) and psychological capital (PsyCap) have recently been introduced into the management literature. This chapter first provides an overview of both the historical and contemporary positive approaches to the workplace. Then, more specific attention is given to the meaning and domain of POB and PsyCap. Our definition of POB includes positive psychological capacities or resources that can be validly measured, developed, and have performance impact. The constructs that have been determined so far to best meet these criteria are efficacy, hope, optimism, and resiliency. When combined, they have been demonstrated to form the core construct of what we term psychological capital (PsyCap). A measure of PsyCap is being validated and this chapter references the increasing number of studies indicating that PsyCap can be developed and have performance impact. The chapter concludes with important future research directions that can help better understand and build positive workplaces to meet current and looming challenges.

Local Calibration of Pavement Mechanistic-Empirical Faulting Reliability using Pavement Management Data

2021 ◽  
pp. 036119812110013
Author(s):  
Lucio Salles de Salles ◽  
Lev Khazanovich
Keyword(s):  
Model Calibration ◽  
Prediction Models ◽  
Plain Concrete ◽  
Performance Model ◽  
Pavement Management ◽  
Pavement Design ◽  
Reliability Model ◽  
Transverse Joint ◽  
Design Characteristics ◽  
And Performance

The Pavement ME transverse joint faulting model incorporates mechanistic theories that predict development of joint faulting in jointed plain concrete pavements (JPCP). The model is calibrated using the Long-Term Pavement Performance database. However, the Mechanistic-Empirical Pavement Design Guide (MEPDG) encourages transportation agencies, such as state departments of transportation, to perform local calibrations of the faulting model included in Pavement ME. Model calibration is a complicated and effort-intensive process that requires high-quality pavement design and performance data. Pavement management data—which is collected regularly and in large amounts—may present higher variability than is desired for faulting performance model calibration. The MEPDG performance prediction models predict pavement distresses with 50% reliability. JPCP are usually designed for high levels of faulting reliability to reduce likelihood of excessive faulting. For design, improving the faulting reliability model is as important as improving the faulting prediction model. This paper proposes a calibration of the Pavement ME reliability model using pavement management system (PMS) data. It illustrates the proposed approach using PMS data from Pennsylvania Department of Transportation. Results show an increase in accuracy for faulting predictions using the new reliability model with various design characteristics. Moreover, the new reliability model allows design of JPCP considering higher levels of traffic because of the less conservative predictions.

scholarly journals Switched Capacitor DC-DC Converters: A Survey on the Main Topologies, Design Characteristics, and Applications

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2231
Author(s):  
Alencar Franco de Souza ◽  
Fernando Lessa Tofoli ◽  
Enio Roberto Ribeiro
Keyword(s):  
Voltage Regulation ◽  
Inherent Difficulty ◽  
Practical Applications ◽  
Dc Power ◽  
Higher Power ◽  
Voltage Doubler ◽  
Converter Design ◽  
Design Characteristics ◽  
And Performance ◽  
Full Charge

This work presents a review of the main topologies of switched capacitors (SCs) used in DC-DC power conversion. Initially, the basic configurations are analyzed, that is, voltage doubler, series-parallel, Dickson, Fibonacci, and ladder. Some aspects regarding the choice of semiconductors and capacitors used in the circuits are addressed, as well their impact on the converter behavior. The operation of the structures in terms of full charge, partial charge, and no charge conditions is investigated. It is worth mentioning that these aspects directly influence the converter design and performance in terms of efficiency. Since voltage regulation is an inherent difficulty with SC converters, some control methods are presented for this purpose. Finally, some practical applications and the possibility of designing DC-DC converters for higher power levels are analyzed.

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