scholarly journals Storage mode of geometrical dimensions in a two-stimulus matching paradigm

1979 ◽  
Vol 25 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Louis C. Boer ◽  
P. J. G. Keuss
Keyword(s):  
Stimulus Matching ◽  
Geometrical Dimensions

Variations in the Compression Strength of Cylindrical Samples Made of Dense Hydroxyapatite

2007 ◽  
Vol 361-363 ◽  
pp. 103-106 ◽  
Author(s):  
Sergey V. Dorozhkin ◽  
Oguzhan Gunduz ◽  
Faik N. Oktar
Keyword(s):  
Ambient Temperature ◽  
Compression Strength ◽  
Total Mass ◽  
Processing Parameters ◽  
Hydraulic Press ◽  
Geometrical Dimensions ◽  
Cylindrical Samples ◽  
Spray Dried

Dense bioceramics made of pure hydroxyapatite (HA) was prepared and characterized. The cylindrical samples were compacted from HA powders of diverse pretreatments; namely, from spray-dried HA, calcined HA and mixtures thereof. The samples were prepared by a hydraulic press under different compaction loads both with and without auxiliary compounds (a binder and a lubricant). Both the total mass and geometrical dimensions of the prepared cylinders were measured. Then, the cylindrical samples were sintered at 1200 °C for 4 hours. After cooling down to ambient temperature, the sintered cylinders were weighed and their geometrical dimensions were measured once again. Mass decreasing and the shrinkage degree were calculated as a result. Afterwards, the compression strength of the sintered cylinders was measured by an Instron 5587 machine. Preparation of dense HA bioceramics possessing the highest possible compression strength was the purpose of this study. The necessary processing parameters were discovered.

Matlab graphical user interface (GUI) code for solar tower power plant performance calculations

2021 ◽  
Vol 21 (1) ◽  
pp. 8-14
Author(s):  
Ihsan N. Jawad ◽  
Qais A. Rishack ◽  
Hussien S. Sultan
Keyword(s):  
User Interface ◽  
Power Plant ◽  
Solar Radiation ◽  
Output Power ◽  
Graphical User Interface ◽  
Operating Conditions ◽  
Plant Performance ◽  
Turbine Efficiency ◽  
Mass Flowrate ◽  
Geometrical Dimensions

In the present research, a Matlab program with a graphical user interface (GUI) has been established for studying the performance of a solar tower power plant (STPP). The program gives the ability for predicting the performance of STPP for different tower dimensions, ambient operating conditions and locations. The program is based on the solution of a mathematical model derived from the heat and mass balance for the tower components. The GUI program inputs are; tower dimensions, solar radiation, ambient temperature, pressure, wind velocity, turbine efficiency, emissivity and absorptivity for collector and ground and thermal conductivity and thickness for ground. However, the GUI program outputs are; temperature and pressure differences across the collector and tower, velocity in the tower, density of air in collector outlet, mass flowrate of air, efficiency for collector and tower, the overall efficiency and output power of STPP. The effect of the geometrical dimensions of STPP and some climatic variables on the plant performance was also studied. The results show that the output power increases with increasing the collector diameter, chimney diameter and solar radiation by an increasing of 0.282 kW/m, 0.204 kW/m and 0.046 kW/(W/m2) respectively.

Analysis of Nonlinear Variation Accumulation in Auto-Body Assembly Process

Manufacturing ◽  
2002 ◽  
Author(s):  
Jun Lian ◽  
Zhongqin Lin ◽  
Fusheng Yao ◽  
Xinmin Lai
Keyword(s):  
Sheet Metal ◽  
State Equation ◽  
Assembly Process ◽  
Transformation Mechanism ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Accumulation Mechanism ◽  
Auto Body ◽  
Non Gaussian ◽  
Geometrical Dimensions

In the assembly process of auto-body, variations in the geometrical dimensions of sheet metal parts and fixtures are inevitable. These variations accumulate through the multi-station assembly process to form the dimensional variations of the final products. Compared with the assembly of rigid parts, the assembly process of the elastic parts is more complex because the variation accumulation patterns rely much on the variations of fixture, jointing methods and mechanical deformation. This paper aims at analyzing the variation transformation mechanism and accumulation characteristics for the assembly of sheet metal parts based on the analysis of dimensional coordination relations among parts and fixtures. Finite element method (FEM) and Monte-Carlo Simulation (MCS) were used to analyze the effect of jointing contact on variation transformation, while a state equation was developed to describe the variation accumulation mechanism. The result of the analysis indicates that the main characteristics of elastic assembly jointing are the overlap jointing methods and elastic contacts action. The fact that the variation transform coefficients (VTC) are variable makes the assembly variation distribution Non-Gaussian even if the dimension variation of parts is Gaussian distribution. The analysis conclusions have potential value for more reasonable tolerance synthesis of elastic parts assembly.

Dimensional Effect of Micro Capillary Pumped Loop

2010 ◽  
Vol 26 (2) ◽  
pp. 157-163 ◽  
Author(s):  
T.-S. Leu ◽  
N.-J. Huang ◽  
C.-T. Wang
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Main Parameter ◽  
Heat Transmission ◽  
Capillary Pumped Loop ◽  
Dimensional Effect ◽  
New Family ◽  
Vapor Line ◽  
Drastic Effect ◽  
Geometrical Dimensions

AbstractThis study discusses the components' geometry and its effect on the capability of heat transmission and pressure drop because of its evident influence on the performance of micro capillary pumped loop (MCPL). On analyzing the dimensional effect on heat transmission and pressure gradient of MCPL device, some results were yielded and addressed as follows: The vapor line was the most important factor among the components of MCPL in heat transmission and pressure drop. Furthermore, the depth of vapor line was the main parameter because of its drastic effect. In addition, at depth of vapor line, hv, ranging from 20 μm to 150 μm, the amount of heat transferred for system will increase, but decrease the pressure drop. However, for hv larger than 150 μm, the heat transfer and pressure drop both will reach a limit. A new family of geometrical dimensions of MCPL possessing an excellent heat flux of 178 W/cm2 would be obtained. These findings will be useful in designing a better MCPL.

MEMS Microresonators Based on Nanocrystalline Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
J. Gaspar ◽  
T. Adrega ◽  
V. Chu ◽  
J. P. Conde
Keyword(s):  
Energy Dissipation ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Quality Factors ◽  
Electrostatically Actuated ◽  
Glass Substrates ◽  
Boron Doped ◽  
Resonance Frequencies ◽  
Geometrical Dimensions

ABSTRACTThis paper describes the fabrication and characterization of thin-film nanocrystalline silicon microresonators processed at temperatures below 110°C on glass substrates. The microelectromechanical structures consist of surface micromachined bridges of boron-doped hydrogenated nanocrystalline silicon (p+-nc-Si:H) deposited at 100°C by hot-wire chemical vapor deposition (HWCVD). The microbridges, which are suspended over an Al gate electrode, are electrostatically actuated and the mechanical resonance is detected in vacuum using an optical setup. The resonance frequency and energy dissipation in p+-nc-Si:H based resonators are studied as a function of the geometrical dimensions of the microstructures. Resonance frequencies between 700 kHz and 36 MHz and quality factors as high as 2000 are observed. A Young's modulus of 160 GPa for the structural bridge film is extracted from the experimental data using an electromechanical model and the main intrinsic energy dissipation mechanisms in nc-Si:H microresonators are discussed.

scholarly journals Determination of the Probability of Penetration of Manure Particles Through the Layers of Ferromagnetic Elements in the Vortex Layer Devices

2021 ◽  
pp. 36-39
Author(s):  
P.I. Gridnev ◽  
◽  
T.T. Gridneva ◽  
Keyword(s):  
Vortex Layer ◽  
Geometrical Dimensions

Theoretical dependences are presented for determining the probability of penetration of manure particles through the layers of rotating ferromagnetic elements in the vortex layer device taking into account their number and geometrical dimensions, and parameters of the working area.

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