Feasibility Study of a Spectral Density Modeling of Thermal Fluctuations in Mixing Tees

2002 ◽  
Author(s):  
C. Vindeirinho
Keyword(s):  
Spectral Density ◽  
Temperature Difference ◽  
Thermal Stresses ◽  
Thermal Fluctuations ◽  
Fluid Temperature ◽  
Flow Rates ◽  
New Approach ◽  
Qualitative And Quantitative ◽  
The Subject ◽  
Density Modeling

In mixing tees, hot and cold fluids meet at a nozzle with different flow rates. The resulting temperature fluctuations create mechanical and thermal stresses on the pipes. Predicting the subsequent fatigue is the subject of on-going research. A new approach was developed in order to obtain a qualitative and quantitative estimate of the damage caused by a flow without necessarily acquiring measures, which is often difficult when studying flows in nuclear plant piping. Several time-series of fluid temperature from mock-up tests were studied. Four specific profiles were recognized. Internal stress was computed and fatigue was calculated according to an algorithm. The influences of the profiles, and of the temperature difference between hot and cold legs, were studied. Finally, an approach was proposed, whereby thermal fluctuations are modeled by an envelope spectral density which is transposed to the characteristics of the studied flow (standard deviation, mean temperature, cold and hot legs temperature difference, flow rate). The use of the envelope signal gives a good estimate of the thermal fluctuations but the damage is over-estimated. On-going calculations are attempting to modify the envelope spectral density to attain more realistic values.

Positive Reintegration as a Way of Small and Medium-Sized Business Development

2012 ◽  
pp. 83-88
Author(s):  
A. Zolotov ◽  
M. Mukhanov
Keyword(s):  
Policy Implementation ◽  
Policy Making ◽  
Economic Reforms ◽  
Alternative Possibility ◽  
New Approach ◽  
Compensation Mechanisms ◽  
Policy Making Process ◽  
Monitoring And Enforcement ◽  
The Subject ◽  
Modernization Process

А new approach to policy-making in the field of economic reforms in modernizing countries (on the sample of SME promotion) is the subject of this article. Based on summarizing the ten-year experience of de-bureaucratization policy implementation to reduce the administrative pressure on SME, the conclusion of its insufficient efficiency and sustainability is made. The alternative possibility is the positive reintegration approach, which provides multiparty policy-making process, special compensation mechanisms for the losing sides, monitoring and enforcement operations. In conclusion matching between positive reintegration principles and socio-cultural factors inherent in modernization process is provided.

Social organization in the Orcadian Neolithic: identification of elite domestic structures and settlements through analysis of excavation data

2018 ◽  
Vol 40 (1) ◽  
pp. 25-53 ◽  
Author(s):  
David MacInnes
Keyword(s):  
Social Organization ◽  
Qualitative Data ◽  
Social Hierarchy ◽  
Published Data ◽  
Early Neolithic ◽  
Late Neolithic ◽  
New Approach ◽  
Qualitative Evidence ◽  
Methods Of Analysis ◽  
The Subject

The nature of social organization during the Orcadian Neolithic has been the subject of discussion for several decades with much of the debate focused on answering an insightful question posed by Colin Renfrew in 1979. He asked, how was society organised to construct the larger, innovative monuments of the Orcadian Late Neolithic that were centralised in the western Mainland? There are many possible answers to the question but little evidence pointing to a probable solution, so the discussion has continued for many years. This paper takes a new approach by asking a different question: what can be learned about Orcadian Neolithic social organization from the quantitative and qualitative evidence accumulating from excavated domestic structures and settlements?In an attempt to answer this question, quantitative and qualitative data about domestic structures and about settlements was collected from published reports on 15 Orcadian Neolithic excavated sites. The published data is less extensive than hoped but is sufficient to support a provisional answer: a social hierarchy probably did not develop in the Early Neolithic but almost certainly did in the Late Neolithic, for which the data is more comprehensive.While this is only one approach of several possible ways to consider the question, it is by exploring different methods of analysis and comparing them that an understanding of the Orcadian Neolithic can move forward.

Ontological Model of Government Documents

2013 ◽  
Author(s):  
Tatiana Vashchilko
Keyword(s):  
Qualitative And Quantitative ◽  
Legal Documents ◽  
Government Documents ◽  
The Subject ◽  
Ontological Model ◽  
Investment Agreements ◽  
Extract Information

The paper develops an ontological model to extract information from government legal documents and facilitate the understanding of its content. In particular, international bilateral investment agreements between countries are the subject of analysis, which aims to quantify their semantic diversity. The paper argues it as an accurate approach to extract qualitative and quantitative information.Cette communication expose un modèle ontologique pour extraire de l’information à partir des documents juridiques du gouvernement et faciliter la compréhension du contenu. Plus particulièrement, les ententes internationales d’investissements bilatéraux entre pays ont fait l’objet d’une analyse, dans le but de quantifier la diversité sémantique. La communication conclut qu’il s’agit d’une approche exacte pour extraire de l’information qualitative et quantitative.

scholarly journals The use of a solution of the inverse heat conduction problem to monitor thermal stresses

2019 ◽  
Vol 108 ◽  
pp. 01003
Author(s):  
Jan Taler ◽  
Piotr Dzierwa ◽  
Magdalena Jaremkiewicz ◽  
Dawid Taler ◽  
Karol Kaczmarski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Power Plants ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Temperature Fields ◽  
Thick Wall ◽  
Fluid Temperature ◽  
Unsteady Temperature

Thick-wall components of the thermal power unit limit maximum heating and cooling rates during start-up or shut-down of the unit. A method of monitoring the thermal stresses in thick-walled components of thermal power plants is presented. The time variations of the local heat transfer coefficient on the inner surface of the pressure component are determined based on the measurement of the wall temperature at one or six points respectively for one- and three-dimensional unsteady temperature fields in the component. The temperature sensors are located close to the internal surface of the component. A technique for measuring the fastchanging fluid temperature was developed. Thermal stresses in pressure components with complicated shapes can be computed using FEM (Finite Element Method) based on experimentally estimated fluid temperature and heat transfer coefficient

scholarly journals Study of the Performance of a Novel Radiator with Three Inlets and One Outlet Based on Topology Optimization

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 594
Author(s):  
Tao Zhou ◽  
Bingchao Chen ◽  
Huanling Liu
Keyword(s):  
Topology Optimization ◽  
Heat Exchanger ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Exchange Capacity ◽  
Numerical Results ◽  
Fluid Temperature ◽  
Channel Depth ◽  
Goal Model ◽  
Flow And Heat Transfer

In recent years, in order to obtain a radiator with strong heat exchange capacity, researchers have proposed a lot of heat exchangers to improve heat exchange capacity significantly. However, the cooling abilities of heat exchangers designed by traditional design methods is limited even if the geometric parameters are optimized at the same time. However, using topology optimization to design heat exchangers can overcome this design limitation. Furthermore, researchers have used topology optimization theory to designed one-to-one and many-to-many inlet and outlet heat exchangers because it can effectively increase the heat dissipation rate. In particular, it can further decrease the hot-spot temperature for many-to-many inlet and outlet heat exchangers. Therefore, this article proposes novel heat exchangers with three inlets and one outlet designed by topology optimization to decrease the fluid temperature at the outlet. Subsequently, the effect of the channel depth on the heat exchanger design is also studied. The results show that the type of exchanger varies with the channel depth, and there exists a critical depth value for obtaining the minimum substrate temperature difference. Then, the flow and heat transfer performance of the heat exchangers are numerically investigated. The numerical results show that the heat exchanger derived by topology optimization with the minimum temperature difference as the goal (Model-2) is the best design for flow and heat transfer performance compared to other heat sink designs, including the heat exchanger derived by topology optimization having the average temperature as the goal (Model-1) and conventional straight channels (Model-3). The temperature difference of Model-1 can be reduced by 37.5%, and that of Model-2 can be decreased by 62.5% compared to Model-3. Compared with Model-3, the thermal resistance of Model-1 can be reduced by 21.86%, while that of Model-2 can be decreased by 47.99%. At room temperature, we carried out the forced convention experimental test for Model-2 to measure its physical parameters (temperature, pressure drop) to verify the numerical results. The error of the average wall temperature between experimental results and simulation results is within 2.6 K, while that of the fluid temperature between the experimental and simulation results is within 1.4 K, and the maximum deviation of the measured Nu and simulated Nu was less than 5%. This indicated that the numerical results agreed well with the experimental results.

Public health as a basic condition for the socio-economic development of the region

2021 ◽  
pp. 18-24
Author(s):  
А.Н. Гайфуллин
Keyword(s):  
Economic Development ◽  
Standard Of Living ◽  
The Public ◽  
Qualitative And Quantitative ◽  
Socio Economic Development ◽  
Quantitative Characteristics ◽  
The Subject ◽  
Health Situation ◽  
Qualitative And Quantitative Characteristics

Социально-экономическое развитие есть планомерная процедура совершенствования уровня жизни, качественных и количественных характеристик, потребляемых общественностью благ. Исходя из ситуации со здоровьем населения в регионе, выставляются соответствующие ориентиры. В разрезе региональной специфики закладываются и реализуются целевые программы, которые одновременно зависят от здоровья населения и направлены, собственно, на улучшение качества его здоровья. Согласно тематике настоящей статьи, ведущий фактор социально-экономического роста - здоровье населения, именно он будет оценен как катализатор искомого регионального развития. Socio-economic development is a systematic procedure for improving the standard of living, qualitative and quantitative characteristics of the goods consumed by the public. Based on the health situation of the population in the region, appropriate guidelines are set. In the context of regional specifics, targeted programs are being laid and implemented, which at the same time depend on the health of the population and are aimed, in fact, at improving the quality of its health. According to the subject of this article, the leading factor of socio-economic growth is the health of the population, it will be evaluated as a catalyst for the desired regional development.

Toward a Modern Theory of Rhetoric: A Tagmemic Contribution

1965 ◽  
Vol 35 (4) ◽  
pp. 450-468 ◽  
Author(s):  
Richard Young ◽  
Alton Becker
Keyword(s):  
Subject Matter ◽  
Linguistic Theory ◽  
Modern Theory ◽  
New Approach ◽  
The Subject

The authors undertake first to define the subject matter of rhetoric as it has been traditionally understood and then to illustrate how aspects of one linguistic theory,tagmemics, can form the basis for a new approach to rhetorical problems

Preparation of Sub-Criteria for Mathematical Modeling of Multi-Criteria Decision Making

2014 ◽  
Vol 1020 ◽  
pp. 765-768
Author(s):  
Eva Berankova ◽  
František Kuda ◽  
Stanislav Endel
Keyword(s):  
Decision Making ◽  
Public Service ◽  
Input Data ◽  
Decision Making Process ◽  
Multi Criteria Decision Making ◽  
Individual Selection ◽  
Qualitative And Quantitative ◽  
Data Analyses ◽  
Quantitative Characters ◽  
The Subject

The subject of this paper is to evaluate criteria in the decision-making process for choosing new usable office facilities in light of a big company or public service seeking for new usable office facilities. The criteria defining the requirements for individual selection variants enter into this decision-making process. These criteria have qualitative and quantitative characters. In order to model the criteria, it is desirable that their values are standardized. The method of standardization of these criteria is given in this paper. In this paper, attention is paid to the decision-making process in the course of choosing new usable facilities in administration objects. This decision-making process is based on input data analyses and on conclusions for a certain selection variant resulting from them.

Flat-Plate Solar Collector in Transient Operation: Modeling and Measurements

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Ahmad M. Saleh ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Differential Equations ◽  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Ambient Air ◽  
Fluid Temperature ◽  
Ambient Conditions ◽  
Flow Rates ◽  
Collector System ◽  
Nodal Model

This paper describes a mathematical model for simulating the transient processes which occur in liquid flat-plate solar collectors. A discrete nodal model that represents the flat-plate solar collector's layers and the storage tank is employed. The model is based on solving a system of coupled differential equations which describe the energy conservation for the glass cover, air gap, absorber, fluid, insulation, and the storage tank. Inputs to the model include the time-varying liquid flow rate, incident solar radiation, and the ambient air temperature, as well as the volume of liquid in the storage tank and initial temperature of the system. The system of differential equations is solved iteratively using an implicit, finite-difference formulation executed with Matlab software. In order to verify the proposed method, an experiment was designed and conducted on different days with variable ambient conditions and flow rates. The comparison between the computed and measured results of the transient fluid temperature at the collector outlet shows good agreement. The proposed method is extremely general and flexible accounting for variable ambient conditions and flow rates and allowing for a geometrical and thermophysical description of all major components of the solar collector system, including the storage tank. The validated, general model is suitable to investigate the effectiveness of various components without the necessity of carrying out experimental work, and the flexible computational scheme is useful for transient simulations of energy systems.

scholarly journals Heat transfer enhancement of car radiator using aqua based magnesium oxide nanofluids

2015 ◽  
Vol 19 (6) ◽  
pp. 2039-2048 ◽  
Author(s):  
Hafiz Ali ◽  
Muhammad Azhar ◽  
Musab Saleem ◽  
Qazi Saeed ◽  
Ahmed Saieed
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Management ◽  
Heat Transfer Performance ◽  
Inlet Temperature ◽  
Fluid Temperature ◽  
Transfer Enhancement ◽  
Volumetric Concentration ◽  
Flow Rates ◽  
Transfer Rates

The focus of this research paper is on the application of water based MgO nanofluids for thermal management of a car radiator. Nanofluids of different volumetric concentrations (i.e. 0.06%, 0.09% and 0.12%) were prepared and then experimentally tested for their heat transfer performance in a car radiator. All concentrations showed enhancement in heat transfer compared to the pure base fluid. A peak heat transfer enhancement of 31% was obtained at 0.12 % volumetric concentration of MgO in basefluid. The fluid flow rate was kept in a range of 8-16 liter per minute. Lower flow rates resulted in greater heat transfer rates as compared to heat transfer rates at higher flow rates for the same volumetric concentration. Heat transfer rates were found weakly dependent on the inlet fluid temperature. An increase of 8?C in inlet temperature showed only a 6% increase in heat transfer rate.

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