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In order to explore the energy saving benefits and economy of ultra-low energy consumption renovation of existing buildings in cold areas under the contract energy management (EPC) mode under different renovation schemes. On the basis of the existing net present value and net present value increment, the net present value rate is proposed as the evaluation index of the transformation plan, so as to realize the comprehensive benefit evaluation of a variety of transformation schemes. The results show that the energy-saving transformation scheme of the project with an external wall of 120 mm rock wool board, a 150 mm extruded polyphenylene board on the roof, and a three-glass single Low-E argon-filled glass on the exterior window has the greatest comprehensive benefits and meets the ultra-low energy consumption standard, the energy saving rate of the envelope transformation reaches 28.07%, and the static recovery period is 5.27 years. This paper provides a design method and reference basis for the ultra-low energy transformation of existing buildings in cold areas using EPC mode.

This study evaluated the potential and environmental benefits of using oil shale residue as a replacement for fine aggregate in concrete through a series of experiments. Initially, the crushing value test confirmed the oil shale residue's value at 16.7%, meeting the load-bearing standards for fine aggregates, thus proving its viability as a complete substitute. Further, the oil shale residue was treated with a 60 mg/L concentration of Tween 80 and other surfactants for oil removal. The treated concrete specimens demonstrated excellent compressive performance and a dense internal structure. Building on this, the mechanical properties of the oil shale residue concrete were explored across different replacement ratios (from 40% to 100%), revealing an increase in compressive strength with higher replacement ratios. In the durability tests, compared to the JZ group, the oil shale residue concrete modified with desulfurization gypsum exhibited a 0.03% reduction in mass loss rate and a 10.13% reduction in relative moving elasticity modulus loss rate, particularly noticeable after 175 freeze–thaw cycles where specimens B1 to B4 exhibited no significant damage, highlighting its remarkable durability. Overall analysis indicated that using oil-removed oil shale residue as a substitute for fine aggregate in concrete, combined with desulfurization gypsum modification, not only enhances concrete performance but also significantly reduces the consumption of natural aggregates and environmental pollution, promoting resource utilization and sustainable development. [ABSTRACT FROM AUTHOR]

为解决玉米胚芽蛋白溶解性低的问题，提高其在食品工业领域的实际应用，以玉米胚芽蛋白为原料,通过酶解、转谷氨酰胺酶(TGase)交联，制备了不同交联时间的玉米胚芽蛋白，利用红外光谱仪和粒度分析仪分析玉米胚芽蛋白结构和表面性质的变化，并检测其溶解性、乳化性、起泡性等功能性质。结果表明：随着交联时间的延长，玉米胚芽蛋白的溶解性、起泡能力、持水性、乳化活性逐渐增强，乳化稳定性变化趋势与之相反，泡沫稳定性先升后降，持油性先降后升；与原样相比，交联3 h的玉米胚芽蛋白的乳化活性提高了16.7倍，持水性和持油性分别增加了9.16%和8.71%；TGase交联反应改变了玉米胚芽蛋白的二级结构，酰胺Ⅰ带的伸缩振动增强， β-转角增多，蛋白质粒径和Zeta电位发生改变，蛋白质结构和表面性质的改变造成其功能性质的变化。综合来看，交联3 h的玉米胚芽蛋白的功能性质表现最佳。 In order to solve the problem of low solubility of corn germ protein and improve its application in the field of food industry, the corn germ protein was used as raw material, and different corn germ proteins were prepared by enzymatic hydrolysis and cross-linking with transglutaminase (TGase) at different cross-linking time, and the changes of structure and surface properties of corn germ protein were analyzed by infrared spectroscopy and particle size analyzer, and the functional properties such as solubility, emulsification and foaming were examined. The results showed that with the increase of cross-linking time, the solubility, foaming ability, water-holding capacity and emulsifying activity of corn germ protein gradually increased, the change of emulsifying stability was opposite, foam stability first increased and then decreased, and oil-holding capacity first decreased and then increased. Compared with the original sample, the emulsifying activity of the corn germ protein prepared by cross-linking for 3 h increased by 16.7 times, and the water-holding capacity and oil-holding capacity increased by 9.16% and 8.71%, respectively. The TGase cross-linking reaction changed the secondary structure of corn germ protein, the stretching vibration of the amide I band was enhanced, the β-turn angle increased, the protein particle size and Zeta potential were changed, and the changes of the protein in structure and surface properties resulted in changes of their functional properties. In conclusion, the 3 h cross-linked corn germ protein shows the best functional properties.