Average Exterior Research Articles

Experimental comparison on the performance of radiative, reflective and evaporative cooling in extremely hot climate: A case study in Chongqing, China

Conventional energy-intensive cooling methods are inadequate for addressing the growing cooling demand exacerbated by severe heat waves. Passive cooling technologies with no energy consumption hold substantial promise as favorable alternatives. Radiative, reflective and evaporative cooling are three emerging passive cooling techniques that operate through either spectrum modification or phase change to effectively reject or dissipate heat. In this study, we investigated the cooling performance of four roof models equipped with a bare surface, as well as radiative, reflective and evaporative cooling technologies on the exterior under extremely hot conditions. The results highlighted the remarkable superiority of radiative cooling, particularly during extremely hot periods, wherein it achieved subambient exterior surface temperature by 2.0 °C during working hours. On sunny days following a rain event, the evaporative cooling exhibited a distinctive cooling performance. However, during working hours from 09:00 to 18:00, the average exterior surface temperature of the evaporative cooling model remained 1.9 °C higher than the ambient temperature and 2.7 °C higher than that of the radiative cooling model. Therefore, radiative cooling demonstrated the most effective cooling performance, and its applications should be further investigated to address the growing demand for cooling under global warming.

Selection of Energy Improvement Factors and Economic Analysis of Standard MDU Complexes in Korean Metropolitan Regions

In Korea, energy consumption within apartments in metropolitan areas accounted for more than 33% of the total energy consumption by buildings in 2020. In this study, in order to increase the energy efficiency of MDU (multi-dwelling unit) complexes in metropolitan areas, improvement factors and economic effects were analyzed using ECO2, a building energy efficiency evaluation program. Optimal improvement measures are proposed, to reduce the economic burden on users by applying energy saving technologies. This study was conducted in four stages; in the first stage, using ECO2 software, five types of apartments were selected as standards among 46 complexes. Standard MDUs were selected if more than two factors were satisfied from among the following: (1) household type, (2) average exterior wall insulation and window performance, (3) average energy consumption and demand per unit area per year, (4) average applied facility system, and (5) average monthly energy demand per unit area. In the second stage, improvement factors were derived by analyzing the 10 most recent energy efficient MDU complexes. The third stage involved analysis of the energy saving effect generated by the improvement of windows and total heat exchangers in five selected complexes. Primary energy consumption per unit area per year improved from 158.8 to 132. kWh/m2y in complex E, which had been upgraded from ‘floor heating system’ to ‘total heat exchanger’. Finally, in the fourth stage, optimal improvement factors were selected for economic analysis. By simultaneously applying the optimal improvement factors, such as windows and total heat exchanger, to the M complex, primary energy consumption per unit area per year was improved from 147.6 to 111.4 kWh/m2 y. When optimal improvement factors were applied to 59 m2, 74 m2, 84 m2 types in complex M, life cycle cost savings of energy consumption for 30 years became $1384~1970.

Magnetar birth: rotation rates and gravitational-wave emission

ABSTRACT Understanding the evolution of the angle χ between a magnetar’s rotation and magnetic axes sheds light on the star’s birth properties. This evolution is coupled with that of the stellar rotation Ω, and depends on the competing effects of internal viscous dissipation and external torques. We study this coupled evolution for a model magnetar with a strong internal toroidal field, extending previous work by modelling – for the first time in this context – the strong protomagnetar wind acting shortly after birth. We also account for the effect of buoyancy forces on viscous dissipation at late times. Typically, we find that χ → 90° shortly after birth, then decreases towards 0° over hundreds of years. From observational indications that magnetars typically have small χ, we infer that these stars are subject to a stronger average exterior torque than radio pulsars, and that they were born spinning faster than ∼100–300 Hz. Our results allow us to make quantitative predictions for the gravitational and electromagnetic signals from a newborn rotating magnetar. We also comment briefly on the possible connection with periodic fast radio burst sources.

Study on crystalline, gelatinization and rheological properties of japonica rice flour as affected by starch fine structure

Although many researches have investigated the effects of starch characteristics on its functional properties to evaluate rice quality, few studies were carried out the correlations between starch molecular structure and rice processing properties. In this study, eight varieties of japonica rice with similar content of protein and lipid and less variant content of amylose (12.12–18.19%) were elaborately selected. The result showed that crystalline and pasting parameters were mainly reliant on the differences in chain length distribution of amylopectin. Amylose content and chain length distribution, especially for average exterior chain length (ECL) and interior chain length (ICL) and their entanglement, showed significant correlation on rheological parameters. Swelling power of rice flour showed negative correlation with amylose content. Furthermore, in temperature-reduction process when the temperature is lower gelatinization temperature of amylopectin, the variation of loss modulus was affected by amylopectin. In addition, the PCA plot clearly revealed the interrelationship of all parameters.

Exploring the potentialities of cool facades to improve the thermal response of Mediterranean residential buildings

Cool materials are characterized by high solar reflectance and by high thermal emissivity, the combination of these two radiative properties allows such construction materials to remain cooler than conventional materials of the same colour under the solar radiation. During the past decades there was a growing interest mainly for roofing and pavements applications, aiming at cooling buildings and cities. This study presents the potentiality of the technology for façade applications in residential buildings, focusing on the performance in the Mediterranean region, where cooling energy uses and urban heat islands are critical issues. The study analyses the performance of cooled and non-cooled buildings by means of dynamic simulations, showing the potentiality of the technology in terms of energy performance and impact on indoor thermal comfort. Calculations are carried out for several building configurations and climatic conditions; also the impact of different solar reflectance values of facades, depending on their orientation, was explored. Cooling energy savings up to 2.9kWh/m2 per 0.1 increase of solar reflectance are calculated. The average indoor operative temperature is reduced up to 1.1°C in non-cooled buildings during the summer period. Average exterior surface temperature reductions up to 7.5°C, with peak reductions up to 25°C, are calculated.

EFFECT OF COVERING MATERIAL AND SHADING ON INTERIOR LIGHT INTENSITY IN POLY-GREENHOUSES

The objective of this research was to examine the influence of two different poly-greenhouse covering material types and their properties on the interior light intensity to choose the proper one for covering under Fayoum depression climatic conditions. Measurements of global solar radiation (GSR) and light intensity were made inside and outside six poly-greenhouse-covered prototype structures (Quonset-style). Each prototype structure was 1.0 m length, 1.0 m width and 0.8 m height. Two small doors in the narrow sides of each prototype were kept open during the day-light for natural ventilation. Results showed that the average transmittance in GSR of both new white polyethylene films and new black screen shade net sheets were 74.05% and 55.45%, respectively. Exposure the poly-greenhouse cover to the climatic conditions reduced its transmittance to global solar radiation (GSR). The relative losses of GSR transmittance were 13.96 % and 17.64 % for both old-cleaned and old-dirty polyethylene films, respectively, as compared with the new polyethylene film (74.05%). The average losses of GSR transmittance were 12.93% and 19.42% for both old-cleaned and old-dirty black screen shade net, respectively, as compared with the new black screen shade net cover (55.45%). The new white polyethylene films and new black screen shade net sheets reduced the interior light intensity of the prototypes by an average of 18.3% and 68.4% as compared with the average exterior light intensity, respectively. In addition, old-cleaned and old-dirty polyethylene films reduced the interior light intensity by an average of 20.8% and 34.8% as compared with the identical new white polyethylene film, respectively. While, old-cleaned and old-dirty black screen shade net reduced the interior light intensity by an average of 27.3% and 39.9 % as compared with the identical new black screen shade net, respectively.

Some significant exterior and reproductive properties of the English Thoroughbred horse population from the stud farm 'Ljubicevo', Serbia

The investigation included 5 stallions (average age of 10.40 years) and 33 mares (average age of 10.33 years) with pedigree of the English Thoroughbred horse breed that are used for breeding on the Stud Farm Ljubicevo - Serbia. The investigation of some significant properties relating to the exterior (at stallions) and reproductive ones (at mares) were carried out in the year 2009. The following average exterior (body) measures of the stallions: the body mass (474.80 kg), withers height (160.46 cm), trunk or body length (161.88 cm), breast circumference (187.96 cm) and tibia circumference (19.22 cm) were within the standards of this horse breed of the age. The gestation period at mares, regardless the sex of a colt, averagely lasted 337.70 days. With the mares having had a male colt, the gestation lasted a little bit longer (338.92 days) than with the mares having had female colts (336.90 days). The difference in the gestation duration (2.02 days) was not statistically significant (P>0.05). Between the age of the mares and the gestation duration (regardless the sex of a colt) it was found a positive slight correlation (rp=0.320). Furthermore, between the age of the mares and the gestation duration it was found medium (rp=0.453) correlation at male colts, and quite poor correlation (rp=0.202) at female colts. Found coefficients of the phenotype correlation were not statistically confirmed (P>0.05).

Average Exterior and Average Interior Link Lengths and Statistical Laws of Topological Structure of Rill Networks in Sloping Fields

Average Exterior and Average Interior Link Lengths and Statistical Laws of Topological Structure of Rill Networks in Sloping Fields

Effect of Amylopectin Structure on the Gelatinization and Pasting Properties of Selected Yam (Dioscorea spp.) Starches

AbstractThis study was aimed at elucidating the decisive structural parameters of amylopectin which govern the gelatinization or pasting behavior of yam starch dispersions, exemplified with four selected yam starches from Dioscorea alata and D. batatas with very similar amylose contents (32.2–34.6%). The results indicated that the yam amylopectins examined showed an average degree of polymerization (DP) of 3469–4474 anhydroglucose units (AGU), average chain length (CL) of 18.8–28.5 AGU, average exterior CL (ECL) of 11.8–16.4 AGU, average interior CL (ICL) of 6.0–11.1 AGU, and a noticeable proportion of extralong (> 100 AGU) and long (40–100 AGU) chains that gave the chain ratio r(el+l)/s (the weight ratio of extralong and long chains to short chains) of 0.88–1.40. Generally, the yam amylopectin with a lower DP and NC possessed a greater CL, ECL, ICL, and r(el+l)/s, associating with a higher blue value (BV) and maximal wavelength (λmax) for their complexes with iodine. D. alata amylopectins exhibited a lower DP, longer chain lengths and greater r(el+l)/s than the D. batata amylopectins. Statistically, r(el+l)/s was decisive for the BV and λmax; while CL and phosphate content were crucial for the gelatinization peak temperature and pasting viscosities of the yam starches examined. The role of swelling power or the volume fraction of dispersed remnants instead in governing the pasting viscosity was also mathematically explored.

Definition of typical and average exterior daylight conditions in different climatic zones

One of the crucial problems in predetermining the role of daylighting in energy efficient buildings is the need for reliable localized data on daylight availability. There have been several approaches to define daylight availability standards using different reference models. It has been found, through validation from recent measured data in Australia, that a theoretical model which introduces empirical formulae utilizing relative sunshine duration, cloud type and cover, and turbidity factors can be used with confidence to define typical and average exterior daylight conditions in different climatic zones.

Variation in the degree of branching of the glycogens and an approximate relationship between average exterior chain length and iodine staining

AbstractPrecise evaluation of the branching characteristics of glycogen complex from a variety of sources was made by replicate determinations of end groups by a reproducible periodate oxidation method and by replicate determinations of the percentage degradation by exhaustive β‐amylase activity. Also, the iodine staining characteristics of these samples were studied. The following observations were made. During the synthesis of glycogen by baker's yeast, there was a significant increase in the average chain length of the glycogen, and the maximal optical absorbance AM of the glycogen–iodine complex doubled. The AM decreased linearly with increasing temperature, and increases in iodine concentration caused increases in both the AM and the wavelength of maximal absorbance. There was a general increase in the AM of the glycogen with increasing exterior chain length, but there were minor deviations due to some dependence on the source of the glycogen. Unlike the linear relationship between the AM per chain and the average chain length of the amyloses, the AM per chain was exponentially related to the average exterior chain length of the glycogens.

Water-soluble lipoproteins from yolk granules in sea urchin eggs. I. Isolation and general properties.

Most of the water-soluble lipoproteins in sea urchin eggs (Hemicentrotus pulcherrimus) were localized within yolk granules. Under hypotonic conditions, yolk granules released lipoproteins and a 24S protein species as high molecular weight components; the lipoproteins constituted about 40% of the total materials released. Three yolk lipoproteins(YLP-1, 2, and 3, in order of quantity) were isolated by ultracentrifugation and gel filtration. The hydrated densities of YLP-1, 2, and 3 were 1.027, 1.062, and 1.009 g/cm(3), respectively. YLP-1, 2, and 3 contained glyceride as a major lipid in quantities of 3.1, 1.8, and 4.3 times the amount of each protein, respectively. These lipoproteins contained large amounts of carbohydrate. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed four major periodic acid-Schiff (PAS) positive polypeptide bands common to the three lipoproteins. All the constituent polypeptides of the 24S protein were also PAS positive. Electron microscopy of negatively stained YLP-1, 2, and 3 revealed the average diameters to be 36, 29, and 48nm, respectively. The 24S protein appeared to be cylindrical in shape with average exterior dimensions of 10--20 nm. Thin-section micrographs showed that yolk granules are packed with particles around 30 nm in diameter, suggesting that these particles are not the 24S proteins but the lipoprotein particles.