458 research outputs found
The performance of a heat pump using nanofluid (R22+TiO2) as the working fluid â an experimental study
It has been well known that the nano-particles, including metals, oxides, carbides, or carbon nanotubes, can increase the conduction and convection coefficients and consequently, enhance the heat transfer. Using nanofluids as working fluids in the refrigeration, air-conditioning and heat pump systems has attracted much attention. This work set-up a test rig to experimentally study the system performance of a heat pump with nanofluid as refrigerant, which was prepared by mixing 5wt% TiO2 with R22. Results show that adding the nano particle TiO2 didnât changed the heat absorbed in the evaporator clearly but increase the heat released in the condenser. As a results, compared to using pure R22, when using R22 + TiO2, the COP of the cooling cycle was decreased slightly, however, the COP of the heating cycle was increased significantly increased power consumption of compression.publishedVersio
Determination of double-K fracture parameters of concrete using bottom-notched splitting test
How Service Guarantee Induces Customer Opportunism Behavior in Online Environment âThe Moderating Role of Customers\u27 Personal Characteristics and Reference Groupâs Relationship Strength
On the internet, the enterprise provides service guarantee, such as return without reason in seven days , to reduce the perceived risk of online customers effectively. Meanwhile, such service guarantee leads some customer opportunistic behavior. Taking the customers\u27 personal characteristics and reference groupâs relationship strength as moderator variables, we conduct an empirical research to study the major factor and itâs effect paths on customer opportunistic behavior by using the scenario role-playing approach. The result shows that higher service guarantee is more likely to induce customer opportunism behavior. And customersâ personality (Machiavellianism) has nothing to do with the relationship. On the contrary, the relationship strength has a significantly moderating role in the impact of service guarantee strength on customersâ opportunistic behavior. Knowing friends of strong relationship have opportunistic behaviors, customer is more likely to choose the similar behavior when they face the higher service guarantee
ANALYSIS ON THE ALLEVIATING EFFECT OF PROMOTING MULTI SENSORY READING MODE ON COLLEGE STUDENTSâ COGNITIVE IMPAIRMENT
Surface Roughness Gradients Reveal TopographyâSpecific Mechanosensitive Responses in Human Mesenchymal Stem Cells
The topographic features of an implant, which mechanically regulate cell behaviors and functions, are critical for the clinical success in tissue regeneration. How cells sense and respond to the topographical cues, e.g., interfacial roughness, is yet to be fully understood and even debatable. Here, the mechanotransduction and fate determination of human mesenchymal stem cells (MSCs) on surface roughness gradients are systematically studied. The broad range of topographical scales and highâthroughput imaging is achieved based on a catecholic polyglycerol coating fabricated by a oneâstepâtilted dipâcoating approach. It is revealed that the adhesion of MSCs is biphasically regulated by interfacial roughness. The cell mechanotransduction is investigated from focal adhesion to transcriptional activity, which explains that cellular response to interfacial roughness undergoes a direct forceâdependent mechanism. Moreover, the optimized roughness for promoting cell fate specification is explored
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