Effect of microwave heating time on the gel properties of chicken myofibrillar proteins and their formation mechanism

The present work was conducted to illustrate the mechanism of gel formation of myofibrillar proteins (MPs) under different microwave heating times. The results showed that the denaturation enthalpy (ΔH) of the MPs significantly decreased when the heating time increased from 3 to 9 s and then completely disappeared as the heating time progressed, indicating that the MPs gradually denatured and subsequently aggregated with increasing heating time, which was further verified by the changes in the secondary structure, electrophoretic bands, and gel properties (e.g., water holding capacity and textural profiles) of the MPs. Microstructural images indicated that the MP gel formed under 12 s had the most compact network, indicating that extended microwave heating time could induce quality deterioration of MP gels. Moreover, the hydrophobic forces, electrostatic forces, and disulphide bonds of the MPs gradually intensified with increasing microwave heating time, suggesting that both non-covalent and covalent bonds could promote molecular denaturation and subsequent aggregation of MPs. In addition, correlation analysis revealed that the changes in the molecular conformation of MPs induced by different microwave heating times could effectively regulate the formation of MP gels and their related properties.     

Contract duration: Barrier or bridge to successful public-private partnerships?

Public-private partnerships (PPPs) are predominantly executed through the use of formal contracts which define the relationship between a public agency and private supplier. As such, a PPP is not a generic contract between buyer and supplier but rather a specific contractual arrangement between a public buyer and private supplier. The contract captures the responsibilities of each party in achieving a specific set of performance objectives. Given budgetary pressures faced by public agencies, there is an increasing need for suppliers to make investments which could reduce future-year costs of meeting contract performance objectives. This research addresses two overarching questions specific to the issue of private, supplier-side investment. First, “how does public agency and private supplier perception of risk influence contract duration?” and second, “how does contract duration influence private investment?” To answer these questions, structured interviews were conducted with those in public agencies and private, supplier firms actively engaged in PPPs. Factors suspected to contribute to the risk position of public and private actors were evaluated. Additionally, linkages between public buyer-private supplier risk position, contract duration and private, supplier-side investment were addressed. Outcomes suggest properly structured long-term contracts may: 1) provide the risk mitigation mechanisms needed for both public and private actors, and 2) facilitate private, supplier-side investment.     

Full-scale experimental investigation on the shock-wave characteristics of high-pressure natural gas pipeline physical explosions

In this study, a series of full-scale high-pressure natural gas pipeline physical explosion experiments were performed, in which the overpressure of the shock waves was measured and analyzed. The concept of “physical explosion linear energy (PEXLE)” was proposed and a “PEXLE model” was established to evaluate shock waves in a cylindrical pipeline with high length–diameter ratio. Equations were fitted to describe the characteristics of peak overpressure, positive pressure duration and specific impulse. Results showed that peak overpressure of shock waves is not influenced by the length of pipeline. With the increase of the propagation distance, specific impulse first increases and then decreases. This indicates that the position of the maximum value of overpressure does not correspond with that of the specific impulse.     

Research on the hot surface ignition of hydrogen‐air mixture under different influencing factors

To further reveal the pre‐ignition characteristics of hydrogen internal combustion engine, the effect of hot surface characteristic parameters on the ignition characteristics of hydrogen‐air mixture was investigated in this research. Based on the prototype of the constant volume combustion bomb with an overhead glow plug, the duration from the heating of the hot surface to the combustion of hydrogen‐air mixture, the so‐called heating duration, was firstly researched under different fuel‐air equivalence ratio, initial temperature, initial pressure, hot surface temperature, and hot surface area, and the influence of each factor on the heating duration was analyzed. The results show that the order of the effect of each factor on the hot surface ignition is as follows: hot surface temperature > initial pressure of hydrogen‐air mixture > equivalent ratio > initial temperature of hydrogen‐air mixture > hot surface area. The influence of the hot surface characteristic parameters on the heating duration was further analyzed in detail. On this basis, the relationship among the critical ignition temperature, the heating duration and the hot surface area was researched and established. The results show that the heating duration is the only major factor affecting the critical ignition temperature. Finally, the research results were applied to analysis the pre‐ignition in hydrogen internal combustion engine.     

节能建筑冬季供暖临界温度

给出了节能建筑供暖临界温度的计算方法，讨论了日照、建筑节能设计的影响，说明日照率低的地区供暖临界温度偏高，日照率高的地区增大南向窗墙比有利于建筑节能。     

火灾后混凝土结构损伤检测方法的探讨

分析了混凝土受火损伤的特点,对近年来国内外关于混凝土受火损伤检测方法的研究进行了综述,对各种方法的特点及发展趋势进行了探讨,在此基础上提出了改进火灾后混凝土损伤检测精度的几点建议。     

住宅单元日照环境的研究

在住宅小区建筑日照已经达到设计规范要求情况下,分析不同位置住宅单元的日照分布,对掌握住宅单元品质,确定合适定价策略有着重要意义.本文根据建筑日照理论,对不同楼层与不同水平位置上住宅单元冬季日照进行了详细计算,分析了住宅小区建筑物布局形态、高度、长度以及朝向对日照分布的影响,获得了有益的结果.     

多种因素影响的工序持续时间的估计

在分析传统的“定额计算法”的基础上,用模糊综合评判方法确定了产量定额的修正系数,提出了多种影响因素的工序持续时间估计方法和实用公式．     

Experimental study of early-age behavior of high performance concrete deck slabs under different curing methods

Curing techniques and curing duration have crucial effects to the strength and durability of concrete. Proper curing can protect against moisture loss from fresh concrete. The objective of this experimental study is to examine the early-age behavior of high-performance concrete (HPC) under various curing methods. Laboratory experiments were conducted to investigate the early-age shrinkage development, temperature change, and evaporation rate when different curing methods were used. Four curing techniques and two curing durations were applied to concrete deck slab and cylindrical specimens. The measured experiment data were also compared with several shrinkage prediction models. The results show that proper moisture-curing methods can effectively reduce concrete temperature due to hydration heat and limit the development of early-age shrinkage strains. The concrete of a longer curing duration would yield lower shrinkage deformation and lower evaporation rate.     

Mathematical modelling of solar radiation incident on tilted surface for photovoltaic application at Bhopal,M.P., India

In general, solar radiations are the combination of beam plus diffuse and ground-reflected radiation. The availability of recorded data on a tilted surface is very rare due to lack of measuring equipment and techniques involved. In this study, a standard procedure is adopted for estimation of solar radiation on a tilted surface for a location in Central region of India. Solar radiation is estimated for three tilted positions: First, solar collector tilt equal to latitude angle, second, solar collector tilt equal to latitude angle +15° and third, solar collector tilt at latitude ?15°. Total global solar radiation estimated on the inclined surface for various photovoltaic (PV) modules was used to obtain the annual energy yield based on the estimated value. It was found that on an average, 14?kWh/m² of annual energy output can be obtained for monocrystalline solar PV module corresponding to the inclination of 23.26° latitude at Bhopal.