scholarly journals COOLING EFFECT IN HEAT SETTING OF POLYESTER FIBER

1975 ◽  
Vol 31 (5) ◽  
pp. T186-T191
Author(s):  
Tomiji Wakida ◽  
Michitaka Takasawa ◽  
Ichizo Aoki ◽  
Nobuhiko Kuroki
1974 ◽  
Vol 30 (12) ◽  
pp. T553-T559
Author(s):  
Tomiji Wakida ◽  
Ichizo Aoki ◽  
Nobuhiko Kuroki

2019 ◽  
Vol 17 (2) ◽  
pp. 69
Author(s):  
Afdhal Kurniawan Mainil ◽  
Sarwo Fikri ◽  
Azridjal Aziz

Mesin pengkondisian udara umumnya digunakan untuk memberikan efek pendinginan (cooling effect). Efek pendinginan dimaksudkan untuk memberikan kenyamanan di ruang yang didinginkan, sehingga rasa nyaman membuat orang betah didalamnya. Mesin pengkondisian udara secara termodinamika kebanyakan beroperasi menggunakan siklus kompresi uap, dimana panas diserapkan disisi evaporator di dalam ruangan, kemudian panas tersebut dibuang di kondensor di luar ruangan. Proses tersebut dapat berlangsung karena kerja kompresor dan penurunan tekanan yang terjadi pada katup ekpansi atau pipa kapiler, sehingga siklus kompresi uap bekerja sempurna. Pada sistem pengkondisian udara biasanya panas terbuang kelingkungan begitu saja, panas tersebut dapat dimanfaatkan untuk memanaskan air dengan penambahan kondensor dummy. Penambahan kondensor dummy pada penelitian ini dilakukan untuk melihat pengaruh penambahan kondensor dummy terhadap beban pendingin, daya kompresi, temperatur, dan Coefficient of Performance (COP). Metode yang digunakan pada penelitian ini ialah metode rancang bangun dan eksperimental. Berdasarkan hasil pengujian, selama pengoperasian 120 menit diperoleh temperatur air panas pada  kondisi tanpa beban (0W), beban 1000W, 2000W dan 3000W berturut-turut adalah 52,83oC, 56,58oC, 57,93oC dan 64,73oC.


2021 ◽  
Vol 13 (3) ◽  
pp. 1537
Author(s):  
Irene Zluwa ◽  
Ulrike Pitha

In the case of building surfaces, the installation of green roofs or green facades can be used to reduce the temperature of the environment and the building. In addition, introducing photovoltaic energy production will help to reduce CO2 emissions. Both approaches (building greenery and photovoltaic energy production) compete, as both of them are located on the exterior of buildings. This paper aims to give an overview of solutions for the combination of building greenery (BG) systems and photovoltaic (PV) panels. Planning principles for different applications are outlined in a guideline for planning a sustainable surface on contemporary buildings. A comprehensive literature review was done. Identified solutions of combinations were systematically analysed and discussed in comparison with additional relevant literature. The main findings of this paper were: (A) BG and PV systems with low sub-construction heights require shallow substrates/low growing plants, whereas in the case of the combination of (a semi)-intensive GR system, a distance of a minimum 60 cm between the substrate surface and lower panel edge is recommended; (B) The cooling effect of the greenery depends on the distance between the PV and the air velocity; (C) if the substrate is dry, there is no evapotranspiration and therefore no cooling effect; (D) A spectrum of different PV systems, sub-constructions, and plants for the combination of BG and PV is necessary and suitable for different applications shown within the publication.


2021 ◽  
Vol 14 (1) ◽  
pp. 151-157
Author(s):  
Marlena Lembicz ◽  
Zbigniew Miszalski ◽  
Andrzej Kornaś ◽  
Katarzyna Turnau
Keyword(s):  

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 268
Author(s):  
Jitong Zhao ◽  
Huawei Tong ◽  
Yi Shan ◽  
Jie Yuan ◽  
Qiuwang Peng ◽  
...  

Microbial-induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties through the precipitation of calcium carbonate (CaCO3) on the contact and surface of soil particles in recent years. In the present experiment, water absorption and unconfined compressive strength (UCS) tests were carried out to investigate the effects of three different fiber types (glass fiber, polyester fiber, and hemp fiber) on the physical and mechanical properties of MICP-treated calcareous sand. The fibers used were at 0%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, and 0.40% relative to the weight of the sand. The results showed that the failure strain and ductility of the samples could be improved by adding fibers. Compared to biocemented sand (BS), the water absorption of these three fiber-reinforced biocemented sands were, respectively, decreased by 11.60%, 21.18%, and 7.29%. UCS was, respectively, increased by 24.20%, 60.76%, and 6.40%. Polyester fiber produced the best effect, followed by glass fiber and hemp fiber. The optimum contents of glass fiber and polyester fiber were 0.20% and 0.25%, respectively. The optimum content of hemp fiber was within the range of 0.20–0.25%. Light-emitting diode (LED) microscope and scanning electron microscope (SEM) images lead to the conclusion that only a little calcite precipitation had occurred around the hemp fiber, leading to a poor bonding effect compared to the glass and polyester fibers. It was therefore suggested that polyester fiber should be used to improve the properties of biocemented sand.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianlong Chang ◽  
Xinlei Duan ◽  
Yang Du ◽  
Baoquan Guo ◽  
Yutian Pan

AbstractBy combining the synthetic jet and film cooling, the incident cooling flow is specially treated to find a better film cooling method. Numerical simulations of the synthetic coolant ejected are carried out for analyzing the cooling performance in detail, under different blowing ratios, hole patterns, Strouhal numbers, and various orders of incidence for the two rows of holes. By comparing the flow structures and the cooling effect corresponding to the synthetic coolant and the steady coolant fields, it is found that within the scope of the investigations, the best cooling effect can be obtained under the incident conditions of an elliptical hole with the aspect ratio of 0.618, the blow molding ratio of 2.5, and the Strouhal number St = 0.22. Due to the strong controllability of the synthetic coolant, the synthetic coolant can be controlled through adjusting the frequency of blowing and suction, so as to change the interaction between vortex structures for improving film cooling effect in turn. As a result, the synthetic coolant ejection is more advisable in certain conditions to achieve better outcomes.


2021 ◽  
pp. 127223
Author(s):  
Mohammad A. Rahman ◽  
Vjosa Dervishi ◽  
Astrid Moser-Reischl ◽  
Ferdinand Ludwig ◽  
Hans Pretzsch ◽  
...  

2021 ◽  
Vol 13 (3) ◽  
pp. 1099
Author(s):  
Yuhe Ma ◽  
Mudan Zhao ◽  
Jianbo Li ◽  
Jian Wang ◽  
Lifa Hu

One of the climate problems caused by rapid urbanization is the urban heat island effect, which directly threatens the human survival environment. In general, some land cover types, such as vegetation and water, are generally considered to alleviate the urban heat island effect, because these landscapes can significantly reduce the temperature of the surrounding environment, known as the cold island effect. However, this phenomenon varies over different geographical locations, climates, and other environmental factors. Therefore, how to reasonably configure these land cover types with the cooling effect from the perspective of urban planning is a great challenge, and it is necessary to find the regularity of this effect by designing experiments in more cities. In this study, land cover (LC) classification and land surface temperature (LST) of Xi’an, Xianyang and its surrounding areas were obtained by Landsat-8 images. The land types with cooling effect were identified and their ideal configuration was discussed through grid analysis, distance analysis, landscape index analysis and correlation analysis. The results showed that an obvious cooling effect occurred in both woodland and water at different spatial scales. The cooling distance of woodland is 330 m, much more than that of water (180 m), but the land surface temperature around water decreased more than that around the woodland within the cooling distance. In the specific urban planning cases, woodland can be designed with a complex shape, high tree planting density and large planting areas while water bodies with large patch areas to cool the densely built-up areas. The results of this study have utility for researchers, urban planners and urban designers seeking how to efficiently and reasonably rearrange landscapes with cooling effect and in urban land design, which is of great significance to improve urban heat island problem.


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