95/05050 Stabilization of an inverted flame by heat radiation from a high-temperature metal melt

1995 ◽  
Vol 36 (5) ◽  
pp. 357
Author(s):  
A. G. Chernyatevich ◽  
L. C. Molchanov ◽  
E. N. Sigarev ◽  
S. A. Dudchenko ◽  
V. V. Vakal’chuk ◽  
...  

Interaction of the upper oxygen jets with the BOF bath considerably effects the hot metal refining flow. To optimize the lances designs and methods of BOF bath blowing, information is needed on the actual physical and technical phenomena taking place during top blowing of BOF bath by groups of ultrasonic and sonic oxygen jets. It was shown that obtaining the information is possible at high temperature simulation of the BOF bath blowing by application oxygen lances of various designs and video registration. Results of previous studies by filming of the blowing in a BOF and OHF presented. Description of modern facilities of high temperature simulation within a multi-purpose 160 and 60‒80 kg BOFs, equipped by special manholes for observation and registration by video camera the physicochemical processes taking place on the surface of the bath presented. In particular the manholes made it possible to observe the processes taking place at various methods of top and combined blowing of the BOF bath by application regular, two-circuit and double-flow oxygen lances. A methodology of test heats carrying out presented, which ensured obtaining important practical information on forming and variation of dimensions of the reaction zone. In particular, information was obtained about the interaction of ultrasonic and sonic oxygen jets with the metal melt, development of afterburning, emission out of reaction zone C to CO2 in the subsonic and sonic oxygen jets with forming high temperature flares directed on the BOF bath surface or penetrated in the foamed slag, emissions of slag-metal suspension out the BOF, forming of metal-slag sculls on the lance tube during the blowing with various level of foamed slag-metal emulsion.


Author(s):  
Shawn M. Allan ◽  
Morgana L. Fall ◽  
Erin M. Kiley ◽  
Pawel Kopyt ◽  
Holly S. Shulman ◽  
...  

1992 ◽  
Vol 62 (6) ◽  
pp. 639-643
Author(s):  
O. S. Esikov ◽  
A. I. Krot ◽  
I. G. Merinov ◽  
E. A. Protasov ◽  
V. P. Sobolev ◽  
...  

2019 ◽  
Vol 11 (3) ◽  
pp. 242
Author(s):  
Trias Budi Wisnu Hartono

The workplace environment has an influence on the workers wellbeing condition, in relation to work activities. Heat pressure arises and causes a burden on the workers who work in high temperature environments. The tofu production process causes heat radiation in the workplace in the Kedung Tarukan Surabaya Tofu Home Industry, whereas almost all activities are carried out in the same location, so that it is likely that workers are exposed to heat continuously during work. The purpose of this study was to analyze the differences of physiological responses of vital signs on the workers in high temperature environments at the tofu home industry Kedung tarukan Surabaya. this study was an observational study with a cross-sectional study design. Data was analyzed statistically using Paired t-test, this study use total population of 14 workers. The results of high temperature measurement of the working area of the Tofu home Industry Kedung Tarukan Surabaya showed that the average value of Wet and Ball Temperature Index (ISBB) was 30.52oC. The workload was categorized as medium, with the workload range of 50% – 75% working hour with workloads in the medium category and 50-75% working time from 1 hour. The results of physiological conditions measurement of vital signs was significantly different (<α 0.05) between before and after work on systolic blood pressure (p = 0.045), pulse (p = 0.039), body temperature (p = 0.006) and respiratory rate (p = 0.014). Whereas there was no significant difference in diastolic blood pressure (p = 0.069). this study concludes that the temperature of the work environment in the tofu home industry Kedung Tarukan Surabaya exceeding the NAB (limit value), caused an extra burden on the workers. It should be clearly informed to the workforce community regarding the potential dangers of working in a high temperature environment. It is also crucial to provide health education about the minimum required liquid consumption needs, providing drinking water for workers, monitoring and managing health safety (K3) in the work environment, and regulating breaks period for workers.


2000 ◽  
Vol 622 ◽  
Author(s):  
Rajiv K. Singh ◽  
Donald R. Gilbert ◽  
Francis Kelly ◽  
Robert Chodelka ◽  
Reza Abbaschian ◽  
...  

ABSTRACTThe use of standard bulk semiconductor crystal growth processes for the production of GaN is prohibited by both the high melt temperature of GaN and thermal decomposition of the compound into Ga metal and N2 gas. We have employed a novel hydrostatic pressure system to grow GaN crystals. A high temperature, ultra-high pressure process was developed using a solid-phase nitrogen source to form GaN crystals in a Ga metal melt. Using a thermal gradient diffusion process, in which nitrogen dissolves in the high temperature region of the metal melt and diffuses to the lower temperature, lower solubility region, high quality crystals up to ∼1 mm in size were formed, as determined by SEM, X-ray diffraction and micro-Raman analysis.


2019 ◽  
Vol 13 (11) ◽  
pp. 21
Author(s):  
Man-Jing Li ◽  
Mao Zhu ◽  
Jia-Xu Han ◽  
Yuan-Biao Zhang

The thermal protective clothing for high-temperature operation usually consists of three-layer fabrics and a gap called the air layer or Layer IV between Layer III and skin. In order to design more effective thermal protective clothing at less cost, based on the heat transfer principles, we establish heat transfer models of fabrics and air layer, which are one-dimensional nonlinear partial differential equations with constant coefficients. In the three-layer fabrics, we consider the effects of heat conduction and heat radiation in Layer I but only consider heat conduction in Layer II and Layer III. Furthermore, the heat transfer model of Layer IV is decoupled and simplified to steady-state heat conduction in Layer IV and radiation heat transfer on surface of Layer IV. According to the explicit difference schemes for the models, we use the parameters in an experiment which puts a thermal manikin in high-temperature environment for some time and measures the temperature of lateral skin at regular time, to solve the models and calculate the temperature of each layer. With MATLAB, the visual interface of three-dimensional temperature distribution is provided, which is reference for functional design of thermal protective clothing. We also compare the simulation result of skin surface with the experimental data. The results show that at the same position, the temperature rises over time but with decreasing rate and finally reaches the steady state. Moreover, at one moment after reaching the steady state, the temperature has a gradual decrease with the increase of distance from the external environment.


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