scholarly journals Optimum thickness of GaAs top layer in AlGaAs‐based 850 nm VCSELs for 56 Gb/s PAM‐4 applications

ETRI Journal ◽  
2021 ◽  
Author(s):  
Shin‐Wook Yu ◽  
Sang‐Bae Kim
Keyword(s):  
Optimum Thickness

Aerodynamic Shape Influence and Optimum Thickness Distribution Analysis of Perceptive Wind Turbine Blade

2018 ◽  
Vol 7 (3) ◽  
pp. 1
Author(s):  
J. V. Muruga Lal Jeyan ◽  
Akhila Rupesh ◽  
Jency Lal
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Thickness Distribution ◽  
Turbine Blades ◽  
Reduced Form ◽  
Load Factor ◽  
Strong Impact ◽  
Theory Approach ◽  
Distribution Analysis ◽  
Optimum Thickness

The aerodynamic module combines the three-dimensional nonlinear lifting surface theory approach, which provides the effective propagated incident velocity and angle of attack at the blade section separately, and a two-dimensional panel method for steady axisymmetric and non-symmetric flow has to be involved to obtain the 3D pressure and velocity distribution on the wind mill model blade. Wind mill and turbines have become an economically competitive form of efficiency and renewable work generation. In the abroad analytical studies, the wind turbine blades to be the target of technological improvements by the use of highly possible systematic , aerodynamic and design, material analysis, fabrication and testing. Wind energy is a peculiar form of reduced form of density source of power. To make wind power feasible, it is important to optimize the efficiency of converting wind energy into productivity source. Among the different aspects involved, rotor aerodynamics is a key determinant for achieving this goal. There is a tradeoff between thin airfoil and structural efficiency. Both of which have a strong impact on the cost of work generated. Hence the design and analysis process for optimum design requires determining the load factor, pressure and velocity impact and optimum thickness distribution by finding the effect of blade shape by varying thickness on the basis of both the aerodynamic output and the structural weight.

scholarly journals Optimum Thickness of Thermal Insulation with Both Economic and Ecological Costs of Heating and Cooling

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3835
Author(s):  
Robert Dylewski ◽  
Janusz Adamczyk
Keyword(s):  
Thermal Insulation ◽  
Construction Materials ◽  
Optimum Thickness ◽  
Degree Days ◽  
Transfer Coefficients ◽  
Cooling Period ◽  
Heating And Cooling ◽  
Optimum Heat ◽  
Materials Used ◽  
Building Walls

The energy efficiency of the construction sector should be determined by the cleanliness of the environment and, thus, the health of society. The scientific aim of this article was to develop a methodology for determining the optimum thickness of thermal insulation, taking into account both economic and ecological aspects and considering both heating and cooling costs. The method takes into account the number of degree days of the heating period, as well as the number of degree days of the cooling period. Variants in terms of different types of thermal insulation, various types of construction materials for building walls, climatic zones and heat sources, were taken into consideration. In order to find the optimum thicknesses of thermal insulation, both in economic and ecological terms, a metacriterion was used. The optimum thicknesses of thermal insulation with the use of the metacriterion were obtained in the range of 0.11–0.55 m. It was observed that the values of the optimum heat transfer coefficients for economic and ecological reasons do not depend on the type of construction materials used for vertical walls. The type of applied heat source is of the greatest importance for the size of the economic and ecological benefits. The proposed mathematical model for determining the optimum thickness of thermal insulation with the use of a metacriterion is a kind of generalization of earlier models from the literature.

scholarly journals Stress Analysis of Pelton Turbine Distributor Using UG-NX Software

2018 ◽  
Vol 7 (4.5) ◽  
pp. 316 ◽  
Author(s):  
Chaman Lal Pal ◽  
Dr. T.S. Desmukh ◽  
Dr. V.K.Gahlot
Keyword(s):  
Stress Analysis ◽  
Complex Shape ◽  
Load Condition ◽  
Practical Case ◽  
Optimum Thickness ◽  
Pelton Turbine

The main objective of this paper is analysis of stress in the distributor to find out optimum thickness for safe and satisfactory working at different load condition. To describe how different plate segments required fabricating wyes branches to ensure greater reliability. The distributor of Pelton turbine consists of pipe segments and wyes branches which are then connected to nozzle. A wyes branch, where the distributor bifurcates has a very complex shape and is very difficult to design. A practical case of distributor of 6 jets vertical Pelton turbine of 43 MW power has been carried but using UG-NX software. 

Heat Transfer Enhancement in Triangular Fin

2008 ◽  
Author(s):  
H. Shokouhmand ◽  
M. Moghaddami ◽  
H. Jafari
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Industrial Applications ◽  
Finned Tube ◽  
Optimum Thickness ◽  
Transfer Enhancement ◽  
Constant Length ◽  
Heat Rejection ◽  
Triangular Fin

Fins are widely utilized in many industrial applications for example, fins are used in air cooled finned tube heat exchangers like car radiators, heat rejection devices, refrigeration systems and in condensing central heat exchangers. In this paper, heat transfer inside the fin system composed of a primary rectangular fin with a number of rectangular fins (secondary fins), which are attached on its surface, is modeled and analyzed numerically. The length of the secondary fins decreases linearly from the base of the primary fin to its tip. This modified triangular fin is a kind of improved tree fin networks. The effectiveness of the modified triangular fin is compared with the effectiveness of triangular fin which is calculated analytically. The results show that adding secondary fins increases the effectiveness of triangular fin significantly. Also, it is found that increasing the number of secondary fins in a constant length of primary fin will increase the effectiveness. In addition, by comparing the results it can be concluded that by shortening the length of the primary fin in modified triangular fin, the effectiveness will increase significantly to the contrary of the triangular fin, so smaller heat exchangers can be built by using the modified triangular fin. It is found that in a constant length of primary fin, there is an optimum thickness of secondary fins which maximize the effectiveness of the fin.

Effect of Adhesive Thickness on the Impact Toughness of Butt-Joints

2011 ◽  
Vol 230-232 ◽  
pp. 1350-1354 ◽  
Author(s):  
Min You ◽  
Jing Rong Hu ◽  
Xiao Ling Zheng ◽  
Ai Ping He ◽  
Cun Jun Chen
Keyword(s):  
Impact Toughness ◽  
Adhesive Layer ◽  
Curing Temperature ◽  
Curing Time ◽  
Optimum Thickness ◽  
Adhesively Bonded ◽  
Butt Joints ◽  
Notched Specimen ◽  
Adhesive Thickness ◽  
The Impact

The effect of the adhesive thickness on the impact toughness of the adhesively bonded steel joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness increases when the adhesive thickness increased then it decrease as the adhesive thickness increase. When the curing time is set as a constant, the higher the curing temperature is, the lower the impact toughness of the joint. The optimum thickness of the adhesive layer for the specimen of impact toughness test cured at 60 C for 1 h is 0.6 mm and it is 0.4 mm to 0.6 mm for the specimen cured 1 h at temperature of 90 C or higher than it. It is recommended using the notched specimen to decrease the testing deviation.

scholarly journals PHOTO-CATALYTIC TRANSPARENT HEAT MIRROR FILM TiO2/TiN/TiO2

2009 ◽  
Vol 12 (3) ◽  
pp. 24-32
Author(s):  
Tran Le ◽  
Nhuan Duy Nguyen ◽  
Cuong Hung Ngo ◽  
Chi Huu Nguyen ◽  
Tuan Tran
Keyword(s):  
Layer Thickness ◽  
Catalytic Properties ◽  
Visible Region ◽  
Infrared Region ◽  
Tio2 Films ◽  
Reactive Magnetron ◽  
Optimum Thickness ◽  
Tio2 Layer ◽  
Glass Substrates ◽  
High Reflectance

Transparenet heat mirror thin films, having high transmittance in the visible region and high reflectance in the infrared region. TiO/TiN/TiO2 films prepared D.C reactive magnetron sputtering method on glass substrates, play role as transparent heat mirror. Besides, the top TiO2 layer has both photo-catalytic and anti-reflective properties. However, st ong thickness dependence of top layer on catalytic properties is a problem need to solve. The experiment shows optimum thickness in order to have good catalytic properties is above 350 nm. This report, we found relationship among thicknesses of films through calculating and experiment. Films prepared, have both catalytic and transparent heat mirror properties with the bottom Tio, layer thickness of 40-300 nm, the middle TiN layer thickness of 16-22 nm and the top TiO2 layer of above 350 nm.

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