Experiments on the transition from the steady to the oscillatory marangoni convection of a floating-zone under various cold wall temperatures and various ambient air temperature effects

2005 ◽  
Vol 17 (4) ◽  
pp. 25-35 ◽  
Author(s):  
Ramazan Selver
1981 ◽  
Vol 54 (5) ◽  
pp. 1113-1123 ◽  
Author(s):  
D. J. Schuring ◽  
G. L. Hall

Abstract The temperature of the ambient air surrounding an operating tire is an important component of the complex thermal system producing rolling loss. Rolling loss is defined as the amount of heat generated by the rolling tire per unit distance. Figure 1 indicates that part of this heat is conducted and stored within the tire body, part is dissipated at the tire surface. The dissipated heat is directly affected by the temperature of the ambient air. Since all heat modes are interactive, the ambient air temperature must therefore influence the heat generated by the tire and, hence, its rolling loss. Presently, relations between ambient air temperature and rolling loss can be established only through measurements; mathematical models of tire heat generation and distribution have not reached a stage where they can be easily applied.


2017 ◽  
Vol 54 (3) ◽  
pp. 803-812 ◽  
Author(s):  
Mahdi Deymi-Dashtebayaz ◽  
Mehdi Farahnak ◽  
Mojtaba Moraffa ◽  
Arash Ghalami ◽  
Nima Mohammadi

1982 ◽  
Vol 17 (1) ◽  
pp. 135-148
Author(s):  
P.T. Wong ◽  
D.S. Mavinic

Abstract The treatability of a municipal leachate (BOD5 = 8090 mg/L) was investigated, by aerobic biostabilization, at a nutrient loading of BOD5:N:P of 100:3.2:1.1. The first stage effluents were subsequently polished by lime-magnesium coagulation. The ranges of ambient air temperature and sludge age studied were 5° to 25°C and 5 to 20 days, respectively. In the biostabilization phase, a BOD5:N:P loading of 100:3.2:1.1 was found to be “adequate” for treatment. Organic and metal removals in the first stage units were excellent. Under all conditions investigated, except for the two units close to washout conditions (5-day sludge age units at 5° and 10°C), BOD5 and COD removals of at least 99.4 and 96.4 percent, respectively, were achieved. Similarly, removal rates for most of the metals monitored were greater than 90 percent. In general, the removal of residual contaminants was not enhanced significantly by the addition of magnesium in the lime-magnesium polishing step.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3398
Author(s):  
Yi Long ◽  
Kun Liu ◽  
Yongli Zhang ◽  
Wenzhe Li

Inorganic cesium lead halide perovskites, as alternative light absorbers for organic–inorganic hybrid perovskite solar cells, have attracted more and more attention due to their superb thermal stability for photovoltaic applications. However, the humid air instability of CsPbI2Br perovskite solar cells (PSCs) hinders their further development. The optoelectronic properties of CsPbI2Br films are closely related to the quality of films, so preparing high-quality perovskite films is crucial for fabricating high-performance PSCs. For the first time, we demonstrate that the regulation of ambient temperature of the dry air in the glovebox is able to control the growth of CsPbI2Br crystals and further optimize the morphology of CsPbI2Br film. Through controlling the ambient air temperature assisted crystallization, high-quality CsPbI2Br films are obtained, with advantages such as larger crystalline grains, negligible crystal boundaries, absence of pinholes, lower defect density, and faster carrier mobility. Accordingly, the PSCs based on as-prepared CsPbI2Br film achieve a power conversion efficiency of 15.5% (the maximum stabilized power output of 15.02%). Moreover, the optimized CsPbI2Br films show excellent robustness against moisture and oxygen and maintain the photovoltaic dark phase after 3 h aging in an air atmosphere at room temperature and 35% relative humidity (R.H.). In comparison, the pristine films are completely converted to the yellow phase in 1.5 h.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Younes Bahammou ◽  
Mounir Kouhila ◽  
Haytem Moussaoui ◽  
Hamza Lamsyehe ◽  
Zakaria Tagnamas ◽  
...  

PurposeThis work aims to study the hydrothermal behavior of mortar cement toward certain environmental factors (ambient air temperature and air velocity) based on its drying kinetics data. The objective is to provide a better understanding and controlling the stability of mortar structures, which integrate the sorption phenomenon, drying process, air pressure and intrinsic characteristics. This leads to predict the comportment of mortar structures in relation with main environmental factors and minimize the risk of cracking mortar structures at an early age.Design/methodology/approachThermokinetic study was carried out in natural and forced convection solar drying at three temperatures 20, 30 and 40°C and three air velocities (1, 3 and 5 m.s-1). The empirical and semiempirical models tested successfully describe the drying kinetics of mortar. These models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures.FindingsThe models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures. The average activation energy obtained expressed the temperature effect on the mortar diffusivity. The drying constant and the diffusion coefficient can be used to predict the influence of these environmental factors on the drying behavior of various building materials and therefore on their durability.Originality/valueEvaluation of the effect of several environmental factors and intrinsic characteristics of mortar structures on their durability.


10.1289/ehp92 ◽  
2016 ◽  
Vol 124 (12) ◽  
pp. 1882-1890 ◽  
Author(s):  
Maria C. Mirabelli ◽  
Ambarish Vaidyanathan ◽  
W. Dana Flanders ◽  
Xiaoting Qin ◽  
Paul Garbe

1958 ◽  
Vol 38 (2) ◽  
pp. 148-159 ◽  
Author(s):  
M. A. MacDonald ◽  
J. M. Bell

This report presents effects of low temperatures on the feed consumption and efficiency of milk production of six mature, lactating, Holstein-Friesian cows that were confined in stanchions for three fortnightly experimental periods during which ambient temperatures measured in degree-hours per day (d-h/day) ranged from 110 to 1152 and daily minimum ambient air temperature (DMAAT) varied from 0° to 38°F. Applying results obtained, it was calculated that as temperatures decreased, i.e., d-h/day increased from 100 to 1200 and DMAAT decreased from 40° to 0°F, average daily intakes of total dry matter, hay, and gross and digestible Calories increased approximately 6.4 lb., 5.3 lb., 13 Therms and 9 Therms, respectively. Each of these increases was statistically significant at the 1 per cent level. Reductions in temperature also decreased gross and net caloric efficiencies of milk production approximately 10 and 8.5 per cent, respectively. These decreases were significant at the 2 per cent level. No correlation was evident between crude protein utilization and temperature.Results indicated that thermal stress was not overcome adequately by supplementary hay intake alone and that appetite stimulation by low temperatures had a carry-over effect continuing at least 24 hours. For continued efficient milk production during winters where low ambient temperatures are prevalent these results suggest it is necessary to provide some form of building insulation, ambient heat and/or provide a high energy supplement to otherwise adequate production rations.


Sign in / Sign up

Export Citation Format

Share Document