Silicon Temperature and Thermal Gradients Measurements in a Rapid Thermal Processor Operating at Atmospheric Pressure or in Vacuum

1987 ◽  
Vol 92 ◽  
Author(s):  
J-M. Dilhac ◽  
C. Ganibal ◽  
A. Martinez
Keyword(s):  
Thermal Radiation ◽  
Experimental Evidence ◽  
Thermal History ◽  
Atmospheric Pressure ◽  
Temperature Drop ◽  
Gas Pressure ◽  
Optical Pyrometer ◽  
Thermal Gradients ◽  
Time Profiles ◽  
Temperature Time

ABSTRACTTemperature-time profiles obtained by an optical pyrometer and a mechanically contacted thermocouple are first presented it appears that the thermocouple response is sensitive to the pressure in the processing chamber. The authors suggest that, in vacuum, the thermocouple is thermally isolated from the wafer, until the temperature is high enough for thermal radiation exchanges to occur. Experimental evidence of the influence of thermal history, and of gas pressure and flow, on temperature drop at periphery of the wafer is then given.

A Model of Tissue Charring During Interstitial Laser Photocoagulation: Estimation of the Char Temperature

1999 ◽  
Author(s):  
William M. Whelan ◽  
Douglas R. Wyman
Keyword(s):  
Laser Photocoagulation ◽  
Continuous Wave ◽  
Laser Energy ◽  
Ex Vivo ◽  
Thermal Gradients ◽  
Tissue Water ◽  
Time Profiles ◽  
Interstitial Laser Photocoagulation ◽  
Interstitial Laser ◽  
Temperature Time

Abstract Interstitial laser photocoagulation (ELP) was performed ex vivo in lean bovine muscle by delivering 1.5 W of continuous-wave 1064 nm Nd:YAG laser energy from a 400 μm core plane-cut optical fiber. The strategy for determining the char temperature involved measuring temperatures where thermal gradients were reduced, and extracting times at which temperature-time profiles displayed interesting nonlinear changes. These times were used to guide a finite difference thermal model, calculating transient temperatures based on two physical descriptions of tissue charring. Modifications in the optical and thermophysical properties due to tissue coagulation (T ≥ 60 °C) and vaporization of tissue water (T ≥ 100°C), respectively, were considered. By placing measured charring dimensions, 2.0 ± 0.3 mm, on calculated temperature-distance profiles, a tissue charring temperature of 414 ± 92°C was estimated.

scholarly journals Contactless and spatially structured cooling by directing thermal radiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicola M. Kerschbaumer ◽  
Stefan Niedermaier ◽  
Theobald Lohmüller ◽  
Jochen Feldmann
Keyword(s):  
Thermal Radiation ◽  
Radiative Heat ◽  
Radiative Cooling ◽  
View Factor ◽  
Temperature Pattern ◽  
Thermal Gradients ◽  
Science And Engineering ◽  
Building Management ◽  
Temperature Manipulation ◽  
Novel Concept

AbstractIn recent years, radiative cooling has become a topic of considerable interest for applications in the context of thermal building management and energy saving. The idea to direct thermal radiation in a controlled way to achieve contactless sample cooling for laboratory applications, however, is scarcely explored. Here, we present an approach to obtain spatially structured radiative cooling. By using an elliptical mirror, we are able to enhance the view factor of radiative heat transfer between a room temperature substrate and a cold temperature landscape by a factor of 92. A temperature pattern and confined thermal gradients with a slope of ~ 0.2 °C/mm are created. The experimental applicability of this spatially structured cooling approach is demonstrated by contactless supercooling of hexadecane in a home-built microfluidic sample. This novel concept for structured cooling yields numerous applications in science and engineering as it provides a means of controlled temperature manipulation with minimal physical disturbance.

Large-area Nanosilver Die-attach by Hot-pressing Below 200°C and 5 MPa

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000129-000134 ◽  
Author(s):  
Kewei Xiao ◽  
Jesus N. Calata ◽  
Hanguang Zheng ◽  
Khai D.T. Ngo ◽  
Guo-Quan Lu
Keyword(s):  
Atmospheric Pressure ◽  
Hot Pressing ◽  
Applied Pressure ◽  
Fractional Factorial ◽  
Maintenance Cost ◽  
Pressing Pressure ◽  
Hot Press ◽  
Large Area ◽  
Die Attach ◽  
Temperature Time

Sintered nanoscale silver joint is an emerging lead-free die-attach solution for high-temperature packaging because of silver's high melting temperature. For bonding small chips, the nanosilver solution can be achieved with a simple heating profile under atmospheric pressure. However, for bonding large-area chips, e.g. > 1 cm2 IGBT chips, uniaxial pressure of a few MPa has been found necessary during the sintering stage of the bonding process, which is carried out at temperatures below 275°C. Hot-pressing at high temperatures can cause significant wear and tear on the processing equipment, resulting in high maintenance cost. In this study, we ran a series of experiments aimed at lowering the hot-pressing temperature. Specifically, we examined a process involving hot-press drying, followed by sintering without any applied pressure. A fractional factorial design of experiments was used to identify the importance and interaction of various processing parameters, such as hot-pressing pressure/temperature/time and sintering temperature/time, on the final bond quality of sintered nanosilver joints. Based on the results, a simpler process, consisting of hot-press drying at 180°C under 3 MPa, followed by sintering at 275°C under atmospheric pressure was found to produce attachments with die-shear strength in excess of 30 MPa.

scholarly journals Preparation of Hydrogen Electrodes of Solid Oxide Cells by Infiltration: Effects of the Preparation Procedure on the Resulting Microstructure

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 131 ◽  
Author(s):  
Bartosz Hołówko ◽  
Jakub Karczewski ◽  
Sebastian Molin ◽  
Piotr Jasiński
Keyword(s):  
Porous Scaffold ◽  
Complex Structure ◽  
Solid Oxide ◽  
Homogeneous Material ◽  
Porous Scaffolds ◽  
Functional Layer ◽  
Time Profiles ◽  
Supporting Layer ◽  
Infiltration Technique ◽  
Temperature Time

In this work, the infiltration technique was used to produce hydrogen electrodes for solid oxide cells. Different infiltration methodologies were tested in order to try to shorten the infiltration cycle time. The porous scaffolds used for infiltration were based on highly porous yttria-stabilized zirconia (YSZ) obtained by etching the reduced nickel from the Ni-YSZ cermet in HNO3 acid. The support had a complex structure which included a ~130 µm porous functional layer with small pores and a ~320 µm thick supporting layer with large pores. Infiltrations have been carried out using aqueous nickel nitrate solutions. Various infiltration procedures were used, differing in temperature/time profiles. The results show that slow evaporation is crucial for obtaining a homogeneous material distribution leading to high-quality samples. A longer evaporation time promotes the proper distribution of nickel throughout the porous scaffold. The shortening of the heat treatment procedure leads to blockage of the pores and not-uniform nickel distribution.

Experimental Evidence of Ca Segregation to Antiphase Boundaries in Pigeonite

2001 ◽  
Vol 7 (S2) ◽  
pp. 254-255
Author(s):  
KT Moore ◽  
DR Veblen ◽  
JM Howe
Keyword(s):  
Experimental Evidence ◽  
Thermal History ◽  
Igneous Rocks ◽  
Cooling History ◽  
Antiphase Boundaries ◽  
Cooling Rates ◽  
History Of ◽  
Antiphase Domains

For over 30 years geologists have been trying to better understand antiphase domains (APD) and boundaries (APB) in pigeonite in hopes of using them as markers for the thermal history of the rocks in which they are found. The ability to know the cooling history of igneous rocks is of great interest to geologists and pigeonite has received special attention on this matter because it has exsolution (precipitation) and antiphase domains (APD), both of which can be used as possible thermal markers. APDs in pigeonite arise because of the C2/c → P21/c transformation that occurs upon cooling. When multiple APDs nucleate, grow, and impinge upon one another, they are either in registry or have a translational discrepancy of ½(a+b). The size of the APDs can be used as a qualitative marker of cooling rates, since slowly cooled pigeonites favor large APDs and rapidly cooled pigeonites favor small APDs.

Quantitative Evaluation of Emulsion Styrene-Butadiene Rubbers and Compounding Variables by Controlled Mixing

1976 ◽  
Vol 49 (1) ◽  
pp. 1-11 ◽  
Author(s):  
S. B. Turetzky ◽  
P. R. Van Buskirk ◽  
P. F. Gunberg
Keyword(s):  
Flow Behavior ◽  
Mixing Time ◽  
Major Constituent ◽  
Time Profiles ◽  
Work Input ◽  
Unit Work ◽  
Work Concept ◽  
Styrene Butadiene ◽  
Temperature Time ◽  
Loading Procedure

Abstract Work reported recently described a “unit work” concept, according to which the flow behavior of a rubber-carbon black mixture was shown to be a function of the mixing work input. These results were shown to be independent of the size of the mixer, the speed of the mixer, and mixing time so long as the temperature-time profiles were similar, the same loading procedure was employed, and the same loading volume percentages were used. This concept provides a means to characterize not only the effect of various polymers, extenders, fillers, and minor additives, but also the uniformity of a given major constituent, which, in the case of an elastomer, may be a processability index. The work described in this paper is the application of the unit work concept to some of these areas : emulsion styrene-butadiene polymers, extenders, and fillers. By means of this concept of mixing, laboratory investigation can be translated, not only qualitatively, but much more important, quantitatively, into factory operations. The effects of polymer molecular weight and bound-styrene content changes, as well as changes in carbon blacks, such as those typified by the new tread blacks, can be investigated in the laboratory, and compounding adjustments can be made there, so that factory production time is not taken for new compound development.

Magnetic Head-Media Interface Temperatures: Part 2—Application to Magnetic Tapes

1987 ◽  
Vol 109 (2) ◽  
pp. 252-256 ◽  
Author(s):  
B. Bhushan
Keyword(s):  
Analytical Model ◽  
Magnetic Particles ◽  
Temperature Drop ◽  
Interface Temperature ◽  
Thermal Gradients ◽  
Asperity Contact ◽  
Sliding Surface ◽  
Magnetic Head ◽  
Head Surface ◽  
Radiometric Technique

An analytical model has been used to predict the interface temperature of a typical magnetic head-tape contact and of isolated (exposed) magnetic particles in contact with the head. Average and maximum interface temperatures for the assumed head-tape interface are about 7° and 10° C, respectively. If the exposed magnetic particles contact the head surface, the average and maximum temperture rises could be about 600° and 900° C, respectively. The duration of an asperity contact is about 2 to 4 μs and the thermal gradients perpendicular to the sliding surface are very large (a temperature drop of 90 percent in a depth of less than the radius of an asperity contact or a few micrometers). The predicted temperatures are compared with the temperatures previously measured using an infrared radiometric technique.

scholarly journals Retorting conditions affect palatability and physical characteristics of canned cat food

2017 ◽  
Vol 6 ◽  
Author(s):  
Esther A. Hagen-Plantinga ◽  
Denmark F. Orlanes ◽  
Guido Bosch ◽  
Wouter H. Hendriks ◽  
Antonius F. B. van der Poel
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Physicochemical Characteristics ◽  
Physical Characteristics ◽  
Physical Parameters ◽  
Time Profiles ◽  
Temperature Time

AbstractThe effects of different temperature and time conditions during retorting of canned cat food on physicochemical characteristics and palatability were examined. For this purpose, lacquer cans containing an unprocessed loaf-type commercial cat food were heated in a pressurised retorting system at three specified temperature–time profiles (113°C/232 min, 120°C/103 min and 127°C/60 min) to equal a similar lethality (F0 value = 30). Physicochemical properties (viscosity, texture, particle size, pH) were determined, and a 10 d three-bowl palatability test was performed with ten European shorthair cats. Retorting at 113°C/232 min resulted in differences in all the physical parameters examined (<viscosity, firmness, adhesiveness, and > particle size). Significant pH differences were observed (6·53, 6·63 and 6·66 for T113/232, 120 and 127°C, respectively). Preference ratios were 0·38, 0·31 and 0·31 for T113/232, 120 and 127°C, respectively (P = 0·067). It can be concluded that different retorting temperature–time profiles with equal F0 value significantly affect physical characteristics and tended to affect palatability of moist cat food.

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