exchange performance
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2021 ◽  
Vol 47 (2) ◽  
pp. 97-110
Author(s):  
Léopold Djoutsa Wamba

This study seeks to identify the factors that can simultaneously improve the environmental and financial performance of a company and determine if an improvement in the environmental performance of a company is accompanied by an improvement in its financial performance. We estimate a system of structural equations using the partial least squares approach applied to data on 351 large European-registered companies extracted from the ASSET4-Environmental, Social, and Governance database for the 2007–2015 period. The results show that the engagement of a company in environmental protection is significantly affected by the system of governance of the company and the availability of financial resources at the 1 and 5% levels, respectively. The results also show that engaging in environmental protection increases the accounting and stock exchange performance of companies. These results thus suggest that the protection of the ecosystem by companies leads to a paradigm, which can form the basis of a model of responsible governance whose goal is to create value while respecting environmental factors.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7400
Author(s):  
Chao Huan ◽  
Sha Zhang ◽  
Xiaoxuan Zhao ◽  
Shengteng Li ◽  
Bo Zhang ◽  
...  

The combined mine backfill–geothermal (CMBG) system can be used to effectively extract geothermal energy by installing a heat exchange tube (HET) in the underground backfilled stopes of mines, which can be used as the heat supply for buildings in mines and the surrounding areas. The efficient performance of this system strongly depends on the thermal exchange process between the HET and its surrounding cemented paste backfill body (CPB). In this study, a validated simulation model is established to investigate the heat exchange performance of CPB, in which the nonuniformly distributed thermal properties in CPB are fully considered. The results indicate that the increase in the porosity has a negative effect on the heat exchange performance of CPB. With the increase in the porosity, the decreased rate of the conductive heat transfer in CPB could be up to approximately 18%. In conditions with seepage flow, the heat transfer capacity of CPB could be effectively improved. Generally, a higher hydraulic conductivity corresponds to a higher heat transfer performance of CPB. When the seepage velocity rose from 2 × 10−6 to 6 × 10−6 m/s, the thermal conductivity of CPB achieved a 114% increase from 1.843 to 3.957 W/(m·K). Furthermore, it was found that the thermal energy accumulates along the seepage flow direction, enhancing the thermal influencing radius of the HET in this direction. Thus, the arrangement of HETs should fully take into account the seepage flow effect. This proposed simulation model could provide a reference for parameter determination and optimization of CMBG systems.


2021 ◽  
Vol 2076 (1) ◽  
pp. 012025
Author(s):  
Liang Zhang ◽  
Anlong Zhang

Abstract The traditional straight wall tube heat exchanger has low heat exchange efficiency, in order to solve this problem, the turbulent flow in wave wall tube heat exchanger was studied by numerical simulation. It is found that the unique corrugated structure of the heat exchange tube in the wave wall tube heat exchanger can improve the flow state of the fluid in the heat exchanger. The average pressure drop of heat exchanger gradually increases with the increase of Reynolds number Re. Under the same conditions, the average pressure drop of wave wall tube heat exchanger is lower than that of straight wall tube heat exchanger. The improvement of heat exchange performance of heat exchanger can not be realized only by increasing the inlet flow of heat exchanger. The wave wall tube heat exchanger can strengthen the heat exchange of the fluid in the heat exchanger.


2021 ◽  
pp. 146808742110366
Author(s):  
Fukang Ma ◽  
Wei Yang ◽  
Yifang Wang ◽  
Junfeng Xu ◽  
Yufeng Li

The scavenging process of two stroke engine includes free exhaust, scavenging, and post intake process, which clears the burned gas in cylinder and suctions the fresh air for next cycle. The gas exchange process of Opposed-Piston Two-Stroke (OP2S) engine with gasoline direct injection (GDI) engine is a uniflow scavenging method between intake port and exhaust port. In order to investigate the characteristics of the gas exchange process in OP2S-GDI engine, a specific tracer gas method (TGM) was developed and the experiments were carried out to analyze the gas exchange performance under different intake and exhaust conditions and opposed-piston movement rule. The results show that gas exchange performance and trapped gas mass are significantly influenced by intake pressure and exhaust pressure. And it has a positive effect on the scavenging efficiency and the trapped air mass. Scavenging efficiency and trapped air mass are almost independent of pressure drop when the delivery ratio exceeds 1.4. Consequently, the delivery ratio ranges from 0.5 to 1.4 is chosen to achieve an optimization of steady running and minimum pump loss. The opposed piston motion phase difference only affects the scavenging timing. Scavenging performance is mainly influenced by scavenging timing and scavenging duration. With the increased phase difference of piston motion, the scavenging efficiency and delivery ratio increased gradually, the trapping efficiency would increase first and decrease then and reaches its maximum at 14°CA.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4107
Author(s):  
Je-Un Jeong ◽  
Dae-Yun Ji ◽  
Kwon-Yeong Lee ◽  
Woonbong Hwang ◽  
Chang-Hun Lee ◽  
...  

In general, the dropwise condensation supported by superhydrophobic surfaces results in enhanced heat transfer relative to condensation on normal surfaces. However, in supersaturated environments that exceed a certain supersaturation threshold, moisture penetrates the surface structures and results in attached condensation, which reduces the condensation heat transfer efficiency. Therefore, when designing superhydrophobic surfaces for condensers, the surface structure must be resistant to attached condensation in supersaturated conditions. The gap size and complexity of the micro/nanoscale surface structure are the main factors that can be controlled to maintain water repellency in supersaturated environments. In this study, the condensation heat exchange performance was characterized for three different superhydrophobic titanium surface structures via droplet behavior (DB) mapping to evaluate their suitability for power plant condensers. In addition, it was demonstrated that increasing the surface structure complexity increases the versatility of the titanium surfaces by extending the window for improved heat exchange performance. This study demonstrates the usefulness of DB mapping for evaluating the performance of superhydrophobic surfaces regarding their applicability for industrial condenser systems.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Lemu Zhou ◽  
Fangyuan Zhou ◽  
Hanbin Ge

Cracks will be generated due to high internal temperature of the massive concrete. Postcooling method is widely employed as a standard cooling technique to decrease the temperature of the poured mass concrete. In this paper, an annular finned cooling pipe which can increase the heat transfer area between the flowing water and its surrounding concrete is proposed to enhance the cooling effect of the postcooling method. Analysis of the interior temperature variation and distribution of the concrete block cooled by the annular finned cooling pipe system and the traditional cooling pipe system was conducted through the finite element models. It is found that, for the concrete block using the proposed annular finned cooling pipe system, the peak value of the interior temperature can be further lowered. Compared with the traditional cooling pipe, the highest temperature of concrete with an annular finned cooling pipe appears earlier than that with the traditional cooling pipe.


2021 ◽  
Vol 17 (2) ◽  
pp. 157-169
Author(s):  
Florian Rödl

Abstract In the first part of his book, Peter Benson elaborates for the common law that fairness in exchange is not only a fundamental principle of contract law, but that it is, moreover, conceptually rooted in the idea of private autonomy. For the common law presumes that a party to a contract intends, in principle, to exchange performance at its value and on fair terms. The following comment shows that this presumption also animates German contract law, including the rules on the review of standard terms. In the second part, Benson develops the image of a harmonious complementarity of private law, which is characterised by transactional justice, and public law, which instantiates distributive justice. The following comment disputes the claimed harmony by demonstrating the fundamental asymmetry in the institutionalisation of both forms of justice in civil society.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Kamel Chadi ◽  
Nourredine Belghar ◽  
Belhi Guerira ◽  
Mohammed Lachi ◽  
Mourad Chikhi

AbstractIn this paper, we numerically study the influence of the addition of parallelogram ribs and pie-shaped ribs in micro-channels on thermal exchange in three dimensions. We design four different silicon micro-channel heat sinks; the first and second cases without ribs, the third case with added pie-shaped ribs, and a fourth case containing parallelogram ribs. The main purpose of this research is to determine the best micro-channel heat sink in which the heat dissipation is sufficient to improve the heat exchange performance of the micro-channel, as well as to improve the cooling of the electronic components. A constant heat flux is applied to the bottom wall of the four micro-channels, and we use liquid diamond-water with a volume concentration of 5% diamond nanoparticles as a coolant, with a Reynolds number chosen between 200 and 600. The numerical results show that the Nusselt number (Nu) of the micro-channel that contains the parallelogram ribs is higher than that for the other cases, and it also yiels lower temperature values on the bottom wall of the substrate compared to the micro-channel containing pie ribs. When increasing the flow velocity, the thermal resistance of the micro-channel decreases in all cases, and we then find the largest value of the friction factor in the fourth case (with parallelogram ribs).


Author(s):  
Ceyda Ozfidan-Konakci ◽  
Evren Yildiztugay ◽  
Halit Cavusoglu ◽  
Busra Arikan ◽  
Fevzi Elbasan ◽  
...  

Graphene oxide has unique physiochemical properties and a large surface area.


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