The influence of mould pre-heat temperature and casting size on the interaction between a Ti–46Al–8Nb–1B alloy and the mould comprising an Al2O3 face coat

2014 ◽  
Vol 146 (3) ◽  
pp. 295-302 ◽  
Author(s):  
X. Cheng ◽  
C. Yuan ◽  
D. Shevchenko ◽  
P. Withey
Keyword(s):  
Author(s):  
V.N. Gadalov ◽  
I.A. Makarova ◽  
A.A. Ivanov ◽  
S.N. Kutepov ◽  
A.V. Filonovich ◽  
...  

The structure and properties of castings obtained using various modifi ers are studied. It is shown that the introduction of multicomponent modifi er containing ultrafi ne powders of titanium carbide, titanium carbonitride leads to decrease in grain, uniform distribution of carbide precipitates and increase in mechanical properties. The critical temperatures of phase transformations in the cast ZhS3DK alloy and its analogue with modifi ers are determined by the differential thermal analysis method. The heat treatment condition of modifi ed cast heattemperature alloys of the ZhS3DK type is corrected.


1981 ◽  
Vol 103 (3) ◽  
pp. 241-243
Author(s):  
L. L. Lukens ◽  
W. P. Schimmel

The effect of operation and maintenance (O&M) costs on energy produced by solar collector systems is crucial to the market penetration of solar process heat as an alternative energy source. In the present paper, a particular O&M operation, regular collector cleaning, is considered in order to determine its effect upon annualized life cycle energy cost. A first-order model of mirror reflectance degradation as a function of time is constructed from experimental data taken at Albuquerque, N.M. This is used as input to a systems optimization model of a line-focus solar collector process heat installation. The energy cost variation is considered as a function of cleaning cost per unit of collector aperture and cleaning interval. Results are presented for a process heat temperature of 177°C.


Author(s):  
Moh. Irma Sukarelawan ◽  
Sriyanto Sriyanto ◽  
Ariati Dina Puspitasari ◽  
Dwi Sulisworo ◽  
Ulfiana Nurul Hikmah

There are limited studies on the diagnosis of heat and temperature misconceptions using a four-tier instrument diagnostic test. Therefore, this study aims to identify misconceptions in heat and temperature material. The survey research was conducted on 164 students at SMAN 2 Bantul. Students were selected using a convenience sampling technique. Identification of student misconceptions using the Four Tier Heat and Temperature Diagnostic Test (4T-HTDT). Students' conceptual understanding is calculated using the percentage technique. The results of this study indicate that there are still many students who have misconceptions on the concept of "heat-temperature as an extensive quantity" and "heat-temperature depends on material objects". The findings are expected to be a strategic step for designing appropriate remedial teaching.


2019 ◽  
Vol 3 (2) ◽  
Author(s):  
L. L. Prill ◽  
T. G. O’Quinn ◽  
M. D. Chao ◽  
J. L. Vipham ◽  
J. M. Gonzalez ◽  
...  

ObjectivesThe objective of this study was to assess if visual degrees of doneness (DOD) are in-line with current published cooking temperatures and to assess differences in perceptions between consumers and chefs.Materials and MethodsTwenty-four paired beef strip loins (IMPS #180) representing four quality grades [Prime, Top Choice, Low Choice, Select] and an additional 12 enhanced Select strip loins were fabricated into 2.54 cm thick steaks and used in the study. Steaks were randomly assigned to one of six DOD: very rare (55°C), rare (60°C), medium-rare (63°C), medium (71°C), well done (77°C), or very well done (82°C). Following cooking, a photograph of the cut steak surface was taken immediately using a digital camera (Canon PowerShot SX620 HS). A digital survey for chefs and consumers was created for the electronic evaluation of the pictures of the internal surface of the cooked steaks. Chefs (n = 83) and consumers (n = 1134) were asked to assess the DOD of digital steak pictures representing multiple DOD and quality grades. Participants were also asked several questions related to how they determine DOD when cooking steaks, about their use of thermometers, and the temperatures they associate with each DOD.ResultsThere were no quality treatment effects (P > 0.05) for any DOD for the images evaluated. Between 14 to 44% of chefs categorized the steak images as the DOD to which it was cooked. For all DOD, 9 to 48% of chefs classified the steak images as 2 or more DOD from the DOD to which the steak was cooked. Of the 1134 consumers, 27 to 35% of consumers categorized steaks as the appropriate DOD. For all DOD, 16 to 36% of consumers identified steaks as 2 or more DOD higher or lower than the DOD that the steak was cooked. When chefs were asked how they determined DOD when cooking beef steaks, 66% of chefs reported using feel or firmness, whereas 28% stated they use a thermometer. Within the chefs that reported use of thermometers, 15% indicated the specific temperature they used was pull-off the heat temperature and 13% used carry-over cooking temperature. To assess DOD when cooking beef at home, 54% of consumers reported they used color, 16% used feel or firmness, and 10% used time. Additionally, 3% of consumers responded that they do not determine DOD. Only 16% of consumers reported using temperature or food thermometer for determining the correct DOD when cooking beef. Consumers that answered to using a food thermometer were then prompted to state the temperature they utilize, being either pull off the heat temperature (69%) or temperature following the post-cooking temperature rise (31%). However, 48 to 61% of consumers that stated they use a thermometer then reported they did not know the temperatures that correspond with each DOD. Additionally, only 14 to 32% of consumers that utilized peak temperatures matched the NCBA temperatures.ConclusionAlthough consumers do not have a good understanding of beef cooking temperatures, they are able to identify DOD of steaks cooked to specified endpoint temperatures. Additionally, chefs do not consistently use the same method when determining DOD and are unable to accurately identify DOD of steaks cooked to specified endpoint temperatures. This lack of uniformity between chefs and consumers on DOD determination can create challenges for foodservice establishments to successfully meet consumer DOD expectations.


Author(s):  
Trinh Thi Tham

In this study, we assessed effects of temperature inversions on air quality in Hanoi, is the capital of Vietnam with the business development speed also as urbanization high in year near here. Temperature inversions occur frequently in the cooler seasons, exacerbating the impact of emissions and diffusions from industry and traffic. This research used concentration of PM2.5 data gathered from 02 automatic air quality monitoring station located North Centre for Environmental Monitoring, Vietnam environment administration and U.S Embassy Hanoi. The data on the change of temperature in the depth was collected from the meteorological stations Hanoi in 2017 aimed to analyze the frequency of the temperature  rating of the Heat Rate of the Heat Temperature and the Heat of the temperature  inversions and impacts of that on concentration of PM2.5 in the atmosphere. The results also revealed that there was statistical difference (Sig. <0,05) between PM2.5 levels in the ambient air on the inversion days and those on the normal day.


1998 ◽  
Vol 545 ◽  
Author(s):  
Y. Shinohara ◽  
Y. Imai ◽  
Y. Isoda ◽  
I. A. Nishida

AbstractThe Harman method was applied to measure thermal conductivity κ of thermoelectric materials, and the reliability of the measured κ was investigated. The quantitative κ requires a highly sensitive technique to measure minute Peltier heat. Temperature difference by Peltier heat pumping was successfully measured by developing the DC method of resistance measurement. κ of n-type Bi2Te3 sintered compact and n-type PbTe boules was measured at 295K by the Harman method. Static comparative method was also applied to obtain the standard value of κ. In the case of Bi2Te3, the κ by the Harman method agreed well with the standard value. In the case of PbTe in the electron concentration ne range <5 × 1024/m3, the κ almost agreed with the standard value. However, PbTe in the ne range ≥1 × 1025/m3 showed a larger κ than the standard value. The Harman method has an error to give the larger κ for the material with a large carrier component κ, of κ This error is due to the fast conduction of Peltier heat by the carrier. The reliable κ can be measured for the material with a small κ,.


Author(s):  
V.N. Gadalov ◽  
A.V. Filonovich ◽  
I.V. Vornacheva ◽  
E.A. Filatov ◽  
I.A. Makarova

The positive effect of alloying elements on the thermal stability of the γ-matrix and the strengthening γ'-phase of casting nickel alloys, and consequently, on the increase in their heat-temperature strength is established. The alloying elements inhibit diffusion processes, thereby increasing the creep resistance of alloys at high temperatures and loads. It is found that the most indicative parameters of the phase composition of the test alloys are the alloying elements distribution coefficients between the γ- and γ'-phases. The basic principles of balanced alloying are formulated, on which the choice of the optimal chemical composition of heat-temperature nickel alloys is carried out.


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