The Revival of Traditional Water Buffalo Cheese Consumption: Class,Heritage and Modernity in Contemporary China

This article provides an ethnography and analysis of the revival of the tradition of indigenous water buffalo cheese and milk product consumption in Shunde, Guangdong. Contrary to the widely held belief that dairy products are not part of the traditional Chinese diet, water buffalo cheese and milk products have been part of the food systems of Guangdong for centuries. But in the past 30 years, these indigenous milk products have been reinvented as a kind of culinary heritage, supplemented by new forms and practices. The popularity of water buffalo milk products in Shunde today has come about as a result of marketing by various agents, including cheese makers, milk merchants, chefs and the government in post-Mao China. Furthermore, the culture of milk consumption in Shunde today has been shaped by both the forces of post-reform economic development, international cultural institutions, the changing perceptions of members of different social classes, and modernity. The reinvented tradition of milk products provides people of different social classes with new ways of consuming milk products and of conducting social interactions.     

MnO2-Based Electrochemical Supercapacitors on Flexible Carbon Substrates

Manganese dioxide films were grown on large area flexible carbon aerogel substrates. Characterization by x-ray diffraction confirmed α-MnO₂ growth. Three types of films were compared as a function of hexamethylenetetramine (HMTA) concentration during growth. The highest concentration of HM TA produced MnO₂ flower-like films, as observed by scanning electron microscopy, whose thickness and surface coverage lead to both a higher specific capacitance and higher series resistance. Specific capacitance was measured to be 64 F/g using a galvanostatic setup, compared to the 47 F/g-specific capacitance of the carbon aerogel substrate. Such supercapacitor devices can be fabricated on large area sheets of carbon aerogel to achieve high total capacitance.     

Plug-load densities for energy analysis: K-12 schools

Benchmarking plug-load densities is essential to bypass arbitrary and/or incorrect inputs used in building energy analysis. As more building simulationists play a decision-making role for the design team, they tend to lean on building energy standards and guidelines for preliminary inputs such as plug-load densities. It is necessary for building energy standards and rating systems to implement plug-load density benchmarks to reward design teams in their efforts to reduce plug-load energy use. Using case study buildings, this paper establishes benchmark plug-load densities for K-12 schools under two new categories – classrooms with computers and classrooms without computers. Eighteen K-12 schools including 9 elementary, 2 middle, and 7 high schools are assessed for actual plug-load densities. For the same case study buildings, four existing approaches – NREL, COMNET, ASHRAE 90.1-1989, and Title-24 are evaluated for plug-load densities. Results show under- and over-estimation of plug-load densities over actual densities. The development of benchmark for K-12 schools will pave way for instituting targets for trimming plug-load densities in new and retrofit building projects.     

Design of Phosphonated Imidazolium-Based Ionic Liquids Grafted on γ-Alumina: Potential Model for Hybrid Membranes

Imidazolium bromide-based ionic liquids bearing phosphonyl groups on the cationic part were synthesized and grafted on γ-alumina (γ-Al₂O₃) powders. These powders were prepared as companion samples of conventional mesoporous γ-alumina membranes, in order to favor a possible transfer of the results to supported membrane materials, which could be used for CO₂ separation applications. Effective grafting was demonstrated using energy dispersive X-ray spectrometry (EDX), N₂ adsorption measurements, fourier transform infrared spectroscopy (FTIR), and special attention was paid to ³¹P and ¹³C solid state nuclear magnetic resonance spectroscopy (NMR).     

Development and Testing of an Energy Storage Material/Phase Change Material Enhanced Heat Sink

A concept of using energy storage material (ESM) or phase change material (PCM) to enhance the heat transfer dissipation by a conventional compact fin-based heat sink is demonstrated. An actual design is developed, fabricated, and tested to demonstrate the heat transfer enhancement. The heat sink is light weight (made with Aluminum) and miniature in size with a total fin length of 26 mm. Test results demonstrated that under a high peak load (4.4 W/cm²) and low duty power cycle (30/55 on/off ratio with a period of 85 sec), the peak temperature at the heating surface with the ESM/PCM heat sink is 5°C lower than that of a conventional heat sink. At the tip of the fin, the peak temperature with the ESM/PCM heat sink is 3°C lower than that of a conventional heat sink. When the external heat transfer coefficient increases (with increase air velocity), the impact of the PCM/ESM on the heat transfer performance is less. A numerical model, based on COMSOL, is developed to provide a theoretical understanding of the experimental observation.     

The effect of gamma-irradiation on the bandgap width of ZnSe

Exposure to gamma-radiation from a ⁶⁰Co source affects the exciton photoluminescence (PL) spectra of single crystal zinc selenide measured at 4.2 K. As the radiation dose increases, the exciton PL maximum first shifts toward higher energies, but then returns to the initial position (in the range of sufficiently high doses). It is concluded that this behavior is due to variations of the semiconductor bandgap width related to the radiation-stimulated solid-state recrystallization and the accumulation of radiation-induced point defects during exposure.     

In vitro behavior of osteoblast-like cells on PLLA films with a biomimetic apatite or apatite/collagen composite coating

To investigate the methods to improve the cell–material interaction of devices or tissue engineering scaffolds made of poly(l-lactic acid) (PLLA) polymer, apatite and apatite/collagen composite coatings were formed on PLLA films within 24 h through accelerated biomimetic processes. In vitro investigation using Saos-2 osteoblast-like cells through cell culture was conducted to assess the biological performance of these biomimetic coatings. The cell morphology on three types of surfaces, viz., PLLA film, PLLA film with the apatite coating, and PLLA film with the apatite/collagen composite coating, was studied using scanning electron microscopy (SEM). Cell viability was estimated using the MTT assay. The differentiated cell function was assessed by measuring the alkaline phosphatase (ALP) activity. The results obtained indicated that the biomimetic apatite and apatite/collagen composite coatings could significantly enhance the proliferation and differentiation of osteoblast-like cells. The apatite/collagen composite coating appears to be promising for the surface modification of PLLA-based devices with much improved interactions with osteoblastic cells.     

Enhancing the performances of recycling folded cascode OpAmp in nanoscale CMOS through voltage supply doubling and design for reliability

Current‐oriented operational amplifier (OpAmp) design has been common for its orderly current‐to‐speed tradeoff. However, for high‐precision or high‐linearity applications, increasing the current does not help much, as the supply voltage (V_DD) and intrinsic gain of the MOSFETs in ultra‐scaled CMOS technologies are very limited. This paper introduces voltage‐oriented circuit techniques to address such limitations. Specifically, a 2xV_DD‐enabled recycling folded cascade (RFC) OpAmp is proposed. It features: (1) current recycling to enhance the effective trans conductance by 4x with no extra power; (2) transistor stacking to boost the output resistance by one to two orders of magnitude; and (3) V_DD elevating to enlarge the linear output swing by 4x. Comparing with its 1xV_DD RFC and FC counterparts, the proposed solution achieves 20‐dB higher DC gain (i.e. 72.8 dB) in open loop and 20‐dB lower IM3 (i.e., –76.5 dB) in closed loop, under the same power budget of 0.6 mW in a 1‐V General Purpose 65‐nm CMOS process. In many applications, these joint improvements in a single stage are already adequate, being more power efficient (i.e. less current paths), stable (i.e. more phase margin), and compact (i.e. no frequency compensation) than multi‐stage OpAmps. Voltage‐conscious biasing and node‐voltage trajectory check ensure the device reliability in both transient and steady states. No specialized high‐voltage device is necessary. Copyright © 2012 John Wiley & Sons, Ltd.