Study on Influences Mold Shape Imposes on Bread Heating Distribution

2013 ◽  
Vol 395-396 ◽  
pp. 925-929
Author(s):  
Ze Hua Chen ◽  
Shao Bo Gao ◽  
Shang Xin Yang ◽  
Hai Yang Zhang
Keyword(s):  
Theoretical Model ◽  
Numerical Model ◽  
Great Influence ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Distribution Uniformity ◽  
Boundary Curvature ◽  
3D Numerical Model ◽  
Bread Production ◽  
Better Than

A 3D numerical model for heating distribution of bread mold in the oven is presented in this study. In the process of bread production, heat effect is influenced by the shape of the mold. Being consistent with the results of calculation, the shape of the mold imposes great influence on the heating distribution uniformity and maximum temperature difference. Because of even boundary curvature, circular mold behaves better than elliptical and rectangular mold. By utilizing the introduced theoretical model, we are able to get the spatial heating distribution of all kinds of mold. And taking three kinds of mold as example, we illustrate that the more uneven the boundary curvature is, the less uniform the heating distribution will be.

Research on the Compatibility of Cement-Based Biomass Materials Modified by Early-Strength Agents

2015 ◽  
Vol 775 ◽  
pp. 287-291
Author(s):  
Hong Qi ◽  
Wei Qi ◽  
Guo Dong Sheng
Keyword(s):  
Hydration Heat ◽  
Hydration Process ◽  
Maximum Temperature ◽  
Mixed System ◽  
Maximum Temperature Difference ◽  
Early Hydration ◽  
Retarding Effect ◽  
Biomass Materials ◽  
Early Strength ◽  
Better Than

Aim at the slow and complicated hydration process of straw-cement mixed system and the retarding coagulation of cement-based biomass material in C3S reaction. To investigate the improving effect of early-strength agents on the hydration process of straw-cement mixed system by adding CaCl2, FeCl3 and Al2(SO4)3 which could increase the release of hydration heat, accelerate the hydration of cement and weaken the retarding effect of dissolved substances from straw. By testing the variation of temperatures in hydration process to analyze the highest hydration temperature (Tmax), the time of reaching the highest hydration temperature (t), the maximum temperature difference (△T) and the compatibility coefficients (CA) of cement-based biomass materials with modified agents and with no modified agents, and evaluate the compatibility of straw-cement mixed system. Experimental results show that Tmax, t and △T these indexes can intuitively reflect the changing characteristics of early hydration heat of cement-based biomass materials, while CA could reflect the early hydration behavior comprehensively and objectively. Meanwhile, when the dosage of early-strength agents is between 3%~8%, the growth of CA shows as follows: CaCl2 is the best, and FeCl3 is better than Al2(SO4)3.

Modeling and Testing a Cold Plate

2006 ◽  
Author(s):  
Bryan R. Wilcox ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Numerical Model ◽  
Thermal Resistance ◽  
Cover Plate ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Water Mixture ◽  
Heat Flow Rate ◽  
Cold Plate ◽  
Maximum Temperature Difference ◽  
Total Thermal Resistance

The objectives of this work were to build and test a liquidcooled cold plate, and then to develop a numerical model to describe the thermal characteristics of the cold plate. An important parameter of interest was the total thermal resistance of the cold plate which is defined as the maximum temperature difference divided by the net heat flow rate. A cold plate was constructed by machining nine parallel, rectangular channels into an aluminum base (1.65 cm × 7.6 cm × 40 cm) upon which an aluminum cover plate was then welded. Twelve thermocouples were used to measure the temperature of the plate (surface and fin tip) and the circulating fluid at the inlet, outlet, and mid-plane. The working fluid was a 50/50 ethylene glycol-water mixture. Three heater blocks were mounted to the cold plate, and the assembly was insulated so that heat loss to the surroundings was minimized. Four runs were performed with flow rates ranging from 56 g/s to 95 g/s, and after steady-state conditions were reached the temperatures were recorded. Using these temperature measurements, the total thermal resistance was calculated. The thermal resistance of the cold plate was also calculated using a one-dimensional numerical model; agreement between the experimental measurements and model predictions is good. The methods described and results presented in this paper are useful to applied thermal engineers.

scholarly journals Seasonal Variations of Daytime Land Surface Temperature and Their Underlying Drivers over Wuhan, China

2021 ◽  
Vol 13 (2) ◽  
pp. 323
Author(s):  
Liang Chen ◽  
Xuelei Wang ◽  
Xiaobin Cai ◽  
Chao Yang ◽  
Xiaorong Lu
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Rapid Urbanization ◽  
The Impact ◽  
The City

Rapid urbanization greatly alters land surface vegetation cover and heat distribution, leading to the development of the urban heat island (UHI) effect and seriously affecting the healthy development of cities and the comfort of living. As an indicator of urban health and livability, monitoring the distribution of land surface temperature (LST) and discovering its main impacting factors are receiving increasing attention in the effort to develop cities more sustainably. In this study, we analyzed the spatial distribution patterns of LST of the city of Wuhan, China, from 2013 to 2019. We detected hot and cold poles in four seasons through clustering and outlier analysis (based on Anselin local Moran’s I) of LST. Furthermore, we introduced the geographical detector model to quantify the impact of six physical and socio-economic factors, including the digital elevation model (DEM), index-based built-up index (IBI), modified normalized difference water index (MNDWI), normalized difference vegetation index (NDVI), population, and Gross Domestic Product (GDP) on the LST distribution of Wuhan. Finally, to identify the influence of land cover on temperature, the LST of croplands, woodlands, grasslands, and built-up areas was analyzed. The results showed that low temperatures are mainly distributed over water and woodland areas, followed by grasslands; high temperatures are mainly concentrated over built-up areas. The maximum temperature difference between land covers occurs in spring and summer, while this difference can be ignored in winter. MNDWI, IBI, and NDVI are the key driving factors of the thermal values change in Wuhan, especially of their interaction. We found that the temperature of water area and urban green space (woodlands and grasslands) tends to be 5.4 °C and 2.6 °C lower than that of built-up areas. Our research results can contribute to the urban planning and urban greening of Wuhan and promote the healthy and sustainable development of the city.

Prefabrication and Erection Technology of Wide Box Girders in Cross-Sea Bridge

2014 ◽  
Vol 1065-1069 ◽  
pp. 882-888
Author(s):  
Yue Huang ◽  
Xing Fa Wu
Keyword(s):  
Great Influence ◽  
Dead Load ◽  
Box Girders ◽  
Box Girder ◽  
Technical Problems ◽  
Line Segments ◽  
Temperature Load ◽  
Quanzhou Bay ◽  
Research Show ◽  
Better Than

In the approach spans of Quanzhou Bay Cross-sea Bridge, these standard spans are 50m or 70m , width is 20.05m.The approach spans have been built by using short Line segments precast and erection method. This is the first application in the cross sea bridges. According to characteristics of this project, the research on prefabrication and erection technology of wide box girders has been carried out to solve the technical problems in the process of construction. The research show that: 1)In precasting process , the vertical deformation of wide box girder is very small under dead load and temperature load etc. so the influence of prefabrication and erection accuracy can be ignored; 2)The temporary anchor using prestressed steel strand better than planished steel; 3) When using epoxy gasket to adjust geometric line shape, the thickness of cemented layer has a great influence on the linear adjustment;4)The epoxy gasket and bridge erecting machine should be used together, Alignment adjustmen could obtain satisfactory results.

Research Regarding the Effects of 120 mm HE Mortar Bombs on Advanced Materials

2021 ◽  
Vol 42 ◽  
pp. 128-134
Author(s):  
Daniela Pintilie ◽  
Iuliana Florina Pană ◽  
Adrian Malciu ◽  
Constantin Puică ◽  
Cristina Pupăză
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Initial Velocity ◽  
High Explosive ◽  
Numerical Approach ◽  
Advanced Materials ◽  
Physical Mechanisms ◽  
Shock Wave Generation ◽  
3D Numerical Model ◽  
Experimental Trials

High Explosive Mortar bombs are used on the battlefield for destroying the manpower, non-armoured equipment and shelters. The paper describes an original experimental and numerical approach regarding the potential threats caused by the detonation of 120 mm HE mortar bombs. The evaluation of the bomb effect presumes the fulfillment of experimental trials that focus on two physical mechanisms which appear after the detonation of the cased high explosive. These mechanisms are the shock wave generation and the fragments propulsion, which were also studied by a numerical model that provides results over the bomb fragmentation mode. The novelty of the paper consists in the calibrated 3D numerical model confirmed by the experimental data, which provides information over the fragmentation process of the case and the initial velocity of its fragments, proving that the main threat of this type of ammunition is the effect through metal fragments. The results of numerical simulation and experimental data are used for their comparative analysis and the assessment of the phenomena.

MODELING THE EFFECT OF HEAT EXCHANGE ON THE EFFICIENCY OF A THERMOELECTRIC COOLER

2020 ◽  
Vol 2 ◽  
pp. 132-135
Author(s):  
O.I. MARKOV
Keyword(s):  
Numerical Calculation ◽  
Heat Exchange ◽  
Solid State ◽  
Numerical Modelling ◽  
Temperature Difference ◽  
Maximum Temperature ◽  
Thermoelectric Cooler ◽  
Maximum Temperature Difference ◽  
Peltier Cooler ◽  
Account Heat

Numerical modelling thermal and thermoelectric processes in a branch of solid–state thermoelectric of Peltier cooler is performed, taking into account heat exchange by convection and radiation. The numerical calculation of the branch was carried out in the mode of the maximum temperature difference.

Analysis of Flow Resistance Influence on Step-Down Process of the Control Rod Hydraulic Drive System

2021 ◽  
Author(s):  
Linqing Yang ◽  
Benke Qin ◽  
Hanliang Bo
Keyword(s):  
Theoretical Model ◽  
Flow Resistance ◽  
Inflection Point ◽  
Great Influence ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Drive System ◽  
Pressure Curve ◽  
Control Rod ◽  
Step Down

Abstract Control rod hydraulic drive system (CRHDS) is a new type of built-in control rod drive technology which is invented by INET, Tsinghua University. The integrated valve (IV) is the main flow control component of the CRHDS. Flow resistance of IV has a great influence on the control rod dynamic step-down process. The step-down performance experiments of CRHDS with different flow resistance of IV were conducted under room temperature conditions. Meanwhile, the theoretical model of hydraulic cylinder step-down process was established and combined with the relationship of the flow resistance of IV under the experimental conditions to get the dynamic response of the hydraulic cylinder. The calculation results of theoretical model agree well with the experimental data. On this basis, the theoretical model of hydraulic cylinder step-down process was applied to the high temperature working conditions with different flow resistance of IV. The analysis results show that at higher working temperature, with the increase of the flow resistance of IV control rod step-down average velocity decreases and step-down time increases correspondingly. There is an inflection point in the transient pressure curve and the pressure of the inflection point decreases gradually with the increase of the flow resistance. The pressure lag time after step-down also decreases. The research results lay the base for the design and optimization of the flow resistance of the IV for the CRHDS.

Optimization of the Case Depth of a Cylinder Made With 4340 Steel by a Control of the Laser Heat Treatment Parameters

2018 ◽  
Author(s):  
Rachid Fakir ◽  
Noureddine Barka ◽  
Jean Brousseau
Keyword(s):  
Heat Treatment ◽  
Numerical Model ◽  
Surface Temperature ◽  
Laser Power ◽  
Case Depth ◽  
Maximum Temperature ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
4340 Steel ◽  
Cylindrical Workpiece

This paper presents a numerical model able to control the temperature distribution along a 4340 steel cylinder heat-treated with Nd: YAG laser. The numerical model developed using the numerical finite element method, was based on a study of surface temperature variation and the adjustment of this temperature by a control of the heat treatment laser power. The proposed analytical approach was built gradually by (i) the development of a numerical model of laser heat treatment of the cylindrical workpiece, (ii) an analysis of the results of simulations and experimental tests, (iii) development of a laser power adjustment approach, and (iv) proposal of a laser power control predictor using neural networks. This approach was made possible by highlighting the influence of the fixed (non-variable) parameters of the laser heat treatment on the case depth, and has shown that it is possible by controlling the laser parameters to homogenize the distribution of the maximum temperature reached on the surface for a uniform case depth. The feasibility and effectiveness of the proposed approach leads to a reliable and accurate model able to guarantee a uniform surface temperature and a regular case depth for a cylindrical workpiece of a length of 50-mm and with a diameter of between 16-mm and 22-mm.

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