Efficiency of Worm Gear Drives Under Transient Operating Conditions

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Manuel Oehler ◽  
Bernd Sauer ◽  
Balázs Magyar
Keyword(s):  
Power Dissipation ◽  
Calculation Model ◽  
Operating Conditions ◽  
Power Losses ◽  
Transient Conditions ◽  
Calculation Results ◽  
Worm Gears ◽  
Gear Drives ◽  
The Relationship ◽  
Over Time

Abstract In oil-lubricated worm gears, all moving components cause power losses during operation. These losses depend, among other things, on the viscosity of the lubricant used, which in turn is determined by the temperature present in the gearbox. The dependency between the temperature and the power dissipation is mutual, and they influence each other. For the analysis of gearboxes under transient conditions, the relationship among operating conditions, power dissipation, and temperature must be considered. In this paper, a method for the analysis of these interrelationships is presented, which is based on the combination of tribological simulation and thermal networks. With the developed calculation model, the gearbox efficiency and the temperature over time can be estimated for arbitrary load cases. The calculation results are compared with measurements on a real gearbox.

On the Relationship between the Structural Form of Concrete and its Resistance

2019 ◽  
Vol 974 ◽  
pp. 373-378
Author(s):  
Violetta V. Bratoshevskaya ◽  
Vladimir N. Mirsoyanov
Keyword(s):  
Relative Content ◽  
Operating Conditions ◽  
Cement Stone ◽  
Structural Components ◽  
Structural Form ◽  
Physical Chemical ◽  
Internal Properties ◽  
The Relationship ◽  
Formed Structure ◽  
Over Time

The capillary-porous structure of cement stone and concrete is known to be mainly characterized by the presence of two major structural components – crystalline and gel-like products in the form of calcium sub-microcrystals of variable composition. The environmental factors cause changes in the structural-mechanical properties of the concrete structure which can be divided into “internal” and “external” ones. The number of internal properties includes those that change the relative content of the structural components of concrete – its composition, hardening conditions, and etc. The external factors include those that act directly on the already formed structure of concrete in operating conditions. These include mechanical, physical, chemical and other factors that affect the properties of the structure over time.

Transient Flow Analysis for Horizontal Axial Down-Wind Turbine

2013 ◽  
Vol 634-638 ◽  
pp. 3821-3824 ◽  
Author(s):  
Gwo Chung Tsai ◽  
Yi Ta Wang ◽  
Wei Shiue Li
Keyword(s):  
Wind Turbine ◽  
Transient Flow ◽  
Flow Analysis ◽  
Operating Conditions ◽  
Field Analysis ◽  
Computer Engineering ◽  
Change Over Time ◽  
Engineering Software ◽  
The Relationship ◽  
Over Time

This study is to carry out a transient flow field analysis on the condition that the wind turbine is working to generate turbine, the wind turbine operating conditions change over time. Purpose of this study tries to find out the rule from the wind turbine changing over time. In transient analysis, the wind velocity on inlet boundary and rotation speed in the rotor field will change over time, and an analytical process is provided that can be used for future reference. At present, the wind turbine model is designed on the concept of down-wind horizontal axis type. The computer engineering software GH Bladed is used to obtain the relationship between the rotor velocity and the wind turbine. Then the ANSYS engineering software is used to calculate the stress and strain distribution in the blades over time. From the analytical result, the relationship between the stress distribution in the blades and the rotor velocity is got to be used as a reference for future wind turbine structural optimization.

A Numerical Approach to the Calculation of the Surface Temperature Distribution of Worm Gears

2017 ◽  
Author(s):  
Philipp Roth ◽  
Werner Sigmund ◽  
Sebastian Born ◽  
Daniel Kadach ◽  
Karsten Stahl
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Simulation Model ◽  
Load Capacity ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Surface Temperature Distribution ◽  
Worm Gears ◽  
Over Time

This paper presents a numerical approach to calculate the distribution of the surface temperature of worm gears, which is needed to determine the scuffing load capacity. The simulation model used for the heat transport as well as its boundary conditions are explained. Exemplary results for various operating conditions and temperature courses over time are presented. A comparison of the simulation model with another model from literature reveals deviating results. It is shown that the deviations can be attributed to limitations of the model from literature. These limitations do not apply to the numerical simulation model that is presented in this paper.

scholarly journals Study of the Application Characteristics of Photovoltaic-Thermoelectric Radiant Windows

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6645
Author(s):  
Wenjie Zhang ◽  
Jiajun Zhang ◽  
Fengcheng Huang ◽  
Yuqiang Zhao ◽  
Yongheng Zhong
Keyword(s):  
Power Generation ◽  
Power Consumption ◽  
Thermoelectric Module ◽  
Operation Time ◽  
Cooling Capacity ◽  
Calculation Model ◽  
Photovoltaic Module ◽  
Photovoltaic Panel ◽  
Calculation Results ◽  
The Relationship

Through experiments and numerical simulation, this paper studies the related performance of a photovoltaic thermoelectric radiation cooling window structure, verifies the accuracy of the established solar thermoelectric radiation window calculation model, and analyzes the cooling performance of different parameters of thermoelectric sheet, radiation plate, and photovoltaic panel. On the basis of considering the relationship between the power generation and power consumption of the structure, the numerical calculation results show that the solar thermoelectric radiation window with non-transparent photovoltaic module (NTPV) has a total cooling capacity of 50.2 kWh, power consumption of 71.8 kWh, and power generation of 83.9 kWh from June to August. The solar thermoelectric radiation window with translucent photovoltaic module (STPV) has a total cooling capacity of 50.7 kWh, power consumption of 71.7 kWh, and power generation of 45.4 kWh from June to August. If the operation time of the thermoelectric module is limited, when the daily operation time of TEM is less than 8 h, the power generation of STPV can meet the power consumption demand of the thermoelectric radiation window from June to August.

scholarly journals Análisis de una serie de tiempo utilizando diseño de experimentos como herramienta de calibración

2015 ◽  
Vol 6 (1) ◽  
pp. 50 ◽  
Author(s):  
Raúl Prada-Núñez ◽  
Cesar Augusto Hernández-Suárez
Keyword(s):  
Time Series ◽  
Energy Consumption ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Model Parameters ◽  
Arima Models ◽  
Deterministic Models ◽  
Relationship Of ◽  
The Relationship ◽  
Over Time

ResumenLas series temporales se usan para estudiar la relación de una variable consigo misma a lo largo del tiempo en intervalos regulares; se consideró el consumo energético de España durante una muestra de 5 días, recurriendo a diversos modelos deterministas se buscaba modelar su comportamiento de la forma más ajustada. Se utiliza el diseño de experimentos para calibrar los parámetros del modelo de HoltWinters validando aquellos efectos que resultan significativos en la minimización del MAPE, con el fin de identificar las Condiciones Operativas Óptimas del modelo. Por último, se evaluan diversos modelos ARIMA aplicados a los residuos obtenidos del modelo de Holt Winters para convertirlo en ruido blanco, utilizando la metodología Box-Jenkins.Palabras claves: modelo Holt-Winters, modelos ARIMA, Series de tiempo. AbstractTime series are used to study the relationship of a variable with itself over time at regular intervals. Energy consumption in Spain was considered for a sample of five days, using various deterministic models sought to model their behavior in the most accurate way. The design of experiments is used to calibrate the model parameters Holt-Winters validating those effects that are significant in minimizing MAPE,in order to identify the optimum operating conditions of the model. Finally, various ARIMA models applied to residues obtained from Holt-Winters model to make it white noise, using the Box-Jenkins methodology are evaluated.Keywords:  Holt-Winters model, ARIMA models, Time series.

Calculation of Sound Radiation Power at Two Ends of Duct System

2011 ◽  
Vol 295-297 ◽  
pp. 2382-2385
Author(s):  
Tao Feng ◽  
Jing Wang ◽  
Bin Liu ◽  
Xue Wu ◽  
Nan Li
Keyword(s):  
Sound Source ◽  
Radiation Power ◽  
Sound Radiation ◽  
Calculation Model ◽  
Sound Power ◽  
Duct System ◽  
Calculation Results ◽  
Source Characteristic ◽  
Sound Radiation Power ◽  
The Relationship

A method to calculate the radiation sound power from the sound source characteristic of the duct component is developed here; The relationship between the sound source characteristic and the acoustical boundary conditions of the duct ends is also researched by the experiment. Based on the two-port model, the sound source characteristic and the sound transfer matrix of the duct component can be obtained by the numerical or experimental methods. The calculation model to predict the radiation sound power at the end of the duct system is deduced from the sound source characteristic of the duct component. A simple experimental duct system to validate the calculation model is setup and the measurement and calculation results are compared here as well.

Investment Traits and Intelligence in Adulthood

2013 ◽  
Vol 34 (2) ◽  
pp. 82-89 ◽  
Author(s):  
Sophie von Stumm
Keyword(s):  
Individual Differences ◽  
Personality Traits ◽  
Fluid Intelligence ◽  
Need For Cognition ◽  
Openness To Experience ◽  
Intelligence Tests ◽  
Crystallized Intelligence ◽  
New Knowledge ◽  
The Relationship ◽  
Over Time

Intelligence-as-knowledge in adulthood is influenced by individual differences in intelligence-as-process (i.e., fluid intelligence) and in personality traits that determine when, where, and how people invest their intelligence over time. Here, the relationship between two investment traits (i.e., Openness to Experience and Need for Cognition), intelligence-as-process and intelligence-as-knowledge, as assessed by a battery of crystallized intelligence tests and a new knowledge measure, was examined. The results showed that (1) both investment traits were positively associated with intelligence-as-knowledge; (2) this effect was stronger for Openness to Experience than for Need for Cognition; and (3) associations between investment and intelligence-as-knowledge reduced when adjusting for intelligence-as-process but remained mostly significant.

Power Values and Power Distance Moderate the Relationship Between Workplace Supervisory Power and Job Satisfaction

2020 ◽  
Vol 19 (3) ◽  
pp. 135-141
Author(s):  
Kenneth D. Locke
Keyword(s):  
Job Satisfaction ◽  
Multilevel Modeling ◽  
Power Distance ◽  
European Social Survey ◽  
Social Survey ◽  
The Relationship ◽  
Workplace Power ◽  
Over Time

Abstract. Person–job (or needs–supplies) discrepancy/fit theories posit that job satisfaction depends on work supplying what employees want and thus expect associations between having supervisory power and job satisfaction to be more positive in individuals who value power and in societies that endorse power values and power distance (e.g., respecting/obeying superiors). Using multilevel modeling on 30,683 European Social Survey respondents from 31 countries revealed that overseeing supervisees was positively associated with job satisfaction, and as hypothesized, this association was stronger among individuals with stronger power values and in nations with greater levels of power values or power distance. The results suggest that workplace power can have a meaningful impact on job satisfaction, especially over time in individuals or societies that esteem power.

Emotional Impact Feedback Changes How We Remember Negative Autobiographical Experiences

2010 ◽  
Vol 57 (5) ◽  
pp. 354-359 ◽  
Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange
Keyword(s):  
Well Being ◽  
The Other ◽  
Personal Perspective ◽  
Emotional Impact ◽  
Potential Mechanism ◽  
Negative Experiences ◽  
Negative Memory ◽  
The Relationship ◽  
Negative Memories ◽  
Over Time

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.

Rethinking social remittances and the migration-development nexus from the perspective of time

2013 ◽  
Vol 10 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Peggy Levitt ◽  
Deepak Lamba-Nieves
Keyword(s):  
Social Influence ◽  
Change Over Time ◽  
Social Remittances ◽  
The Relationship ◽  
Migration And Development ◽  
Over Time

This article explores how the conceptualization, management, and measurement of time affect the migration-development nexus. We focus on how social remittances transform the meaning and worth of time, thereby changing how these ideas and practices are accepted and valued and recalibrating the relationship between migration and development. Our data reveal the need to pay closer attention to how migration’s impacts shift over time in response to its changing significance, rhythms, and horizons. How does migrants’ social influence affect and change the needs, values, and mind-frames of non-migrants? How do the ways in which social remittances are constructed, perceived, and accepted change over time for their senders and receivers?

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