37 research outputs found
The Process of Reestablishing Home: Returned Indonesian Chinese in Songping Farm
No full text本文以生活在松坪农场的印尼归侨群体为个案 ,追溯其在特殊情境下跨国迁徙、安家农场的历史过程 ,从记忆、现实与向往三个层面 ,探讨该群体对于“家”之归属感的建构及特点Taking returned Indonesian Chinese as a case, this paper traces the processes of their resettlement in Songping Farm after a transnational migration. Through three perspectives, i.e., memory, reality and expectation, the author argues that the returned migrants memory of the life in Indonesia before their return has actively influenced their efforts in building their new home in China and their expectation for a better future has guided their daily life as well
Social Memory and Construction of Identity: A case study on the returned Overseas Chinese in Songping Farm
No full text本文选择华侨农场和生活在农场里的归侨作为研究对象 ,运用社会记忆的相关理论 ,通过参与观察及口述访谈 ,剖析社会记忆如何作用于归侨的认同建构。本文提出 ,在对国家或地方的认同建构上 ,“归侨意识”始终贯串着归侨的集体记忆 ,认同建构是情景性的 ,流动的 ,是一个交织着多重利益的复杂的心理过程。本文希望通过实证研究 ,达到反思移民安置与地方融入这一社会现象的目的。对移民的安置不但是提供物质性安排 ,更重要的是营建一个和谐宽容的社会心理环境 ,使移民与安置地尽快融为一体 ,共谋发展On the basis of oral documents, this article studies the construction of the collective identity cherished by the returned Overseas Chinese in Songping Farm. The author tries to analyze how the returned Overseas Chinese identity has become the cohesion of the group, and the deep meaning of collective social memory and structural amnesia are explored along with the change of time, place and situation. It is argued that in order to improve the integration of the returned migrants into the local society, it is much more important to create social environments full with harmony and equality than simply provide necessary materials
Investigation on Thermal Conductivity of Ni-P-PTFE Composite Coating on Copper Tubes
No full textCopper tubes covered by Ni-P-PTFE composite coating can mitigate fouling adhesion on the heat exchange surface. However, the impact of composite coating on the thermal conduction of copper tubes should be considered. A thermal resistance method was utilized to measure the heat transfer coefficient of copper tubes with Ni-P-PTFE composite coatings. The thermal conductivities of these Ni-P-PTFE composite coatings were gained by means of Wilson plot in the end. The effects of Ni, PTFE, C and P contents were discussed on the thermal conductivity of Ni-P-PTFE composite coating. The results showed the thermal conductivity of these Ni-P-PTFE composite coatings were weakened by the increases of PTFE and P contents, but enhanced when the C content increased. It reached a peak value 23.12 W/(m.K) when w(PTFE)=1.76%, w(C)=3.82% and w(P)=10.81%, respectively. Although the thermal conductivities of the composite coatings were lower, their thermal resistances in the total heat transfer process were from 9.91×10-5 to 1.6×10-4(m2.K)/W due to their small thickness. Therefore, the tubes with Ni-P-PTFE composite coatings still kept high thermal conductivities 314.88~357.55W/(m.K)
Modeling and optimization of a utility system containing multiple extractions steam turbines
No full textHeat Transfer Characteristics of Microencapsulated Phase Change Material Slurry in a Minichannel with Nonuniform Heat Flux
No full textAs a new functional thermal fluid, microencapsulated phase change material slurry (MEPCMS) has development potential in thermal management and other fields. In this study, the discrete phase model (DPM) was used to investigate the heat transfer characteristics of MEPCMS in a horizontal rectangular minichannel under nonuniform heat flux conditions. The results show that the heat transfer can be enhanced by the phase change of particles in the slurry, and the slurry can reduce the wall temperature rise by 8.79% and the fluid temperature rise by 15.14% at a heat flux distribution of 9–5–5 W/cm2, inlet velocity of 0.40 m/s, and mass fraction of 10%. Thermophoretic force causes the particles to migrate to the low-temperature region during the flow. Compared with the uniform heat flux condition, the region and magnitude of the local heat flux affect the heat transfer characteristics in this and later regions. As the inlet velocity and particle mass fraction increase, the cooling effect of the fluid on the wall improves. However, the pressure drop also increases owing to the influence of the streamwise resistance and two-phase interaction
Mathematical Optimization of the Liquid Separation Condenser Used in the Organic Rankine Cycle
No full textAbstractThe liquid separation condenser (LSC) is superior in terms of performance because of its relatively low pressure drop without reducing heat transfer coefficients. It is compact, material saving, and suitable for use in the organic Rankine cycle. However, the total performance of LSC is dependent on tube and fin configurations. A suitable combination of these structural parameters can improve LSC performance significantly. In this study, a mixed-integer nonlinear programming (MINLP) model is formulated to optimize the tube pass, tube number per pass, tube length, tube diameter, and fin number simultaneously. The objective function is the annual total cost of investment and operation. A solution is proposed to solve the formulated MINLP model. A case study is presented to verify the model and solution algorithm
Synthesis and Design of a Trigeneration System of Large Public Buildings
No full textAbstractBuilding energy systems, especially large public building energy systems (LPBES), are major energy consumers and pollutant emissions contributors. In this paper, a superstructure of LPBES incorporating the candidate equipments and their possible combinations are constructed. The thermodynamic performance model, investment cost model, CO2 emission model of the equipments are formulated. The variations of the energy demand and power importation price are addressed by multiple scenarios problem. A multi-objective mixed integer linear programming (MILP) model is formulated. The economic objective is the minimization of the total annual cost of the LPBES and the environmental objective is the minimization of the annual global CO2 emission. The augmented ɛ–constraint method is applied to achieve the Pareto Frontier of the design configuration to reflect the set of solutions representing optimal trade-offs between the economic and environmental objectives. The synthesis and design of the energy system of an airport in north China is studied to test the proposed synthesis and design strategy and the formulated model. Economic optimal scheme and environmental optimal scheme are presented. The Pareto solutions consist of optimal configurations that adapt their operational strategy during a specific range in the Pareto Frontier are presented to show the trade-offs scheme between economic and environmental objectives
Synthesis and Properties of Inositol Nanocapsules
No full textSugar alcohols are phase-change materials with various advantages but may suffer from leakage during applications. In this study, inositol nanocapsules were synthesized at various conditions, including the amount of precursors and the time for adding the precursors. The effects of synthesis conditions on the properties of the nanocapsules were studied. The morphology, chemical composition, microstructure, phase-change characteristics and size distribution of the nanocapsules were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), differential scanning calorimeter (DSC) and a zeta potential analyzer. The results confirm that inositol was well-encapsulated by an SiO2 shell. The shell thickness increased, while the supercooling degree of the nanocapsules decreased with increasing time for adding the precursors. In order to obtain nanocapsules with good morphology and phase-change characteristics, the time for adding the precursors should increase with the amount of precursors. The nanocapsules with the best properties exhibited high melting enthalpy, encapsulation ratio and energy storage efficiency of 216.0 kJ/kg, 83.1% and 82.1%, respectively. The size of the nanocapsules was remarkably affected by the triethoxysilane (TES) amount
Reduction of supercooling of water by TiO<sub>2</sub> nanoparticles as observed using differential scanning calorimeter
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