钢管挡拨料机的类型及应用

介绍了近几年钢管生产线上几种技术比较先进的挡拨料机类型,如星轮拨料机、翻料钩、翻板装置、挡翻料机、挡料给料机等,以及这些设备的组成和特点;分析了挡拨料机在不同的场合下发挥的作用。在生产实践中,结合用户不同的需要、不同的生产节奏,合理选用挡拨料机,将有利于优化工艺生产线,提高钢管的质量和产量。     

硬质聚氨酯泡沫在城市集中供热管道上的应用

介绍了城市集中供热管道用硬质聚氨酯泡沫的笥能和组合原料的工艺参数，并对保温管道的3种生产工艺如手工浇注法，一步法连续生产及二步法生产工艺进行了介绍了比较，给出了直埋供热管道保温层厚度的理论计算公式。     

Effect of heating rate on the recrystallization microstructure and property of ultra-low-carbon steel

In the present work,the microstructure,texture,and mechanical properties of a cold-rolled Ti-IF steel, after annealing at different heating rates,have been investigated.The results reveal that the mean grain size is gradually refined from19.2 to 16.3μm as the heating rate increases from4 to50℃/s,but refined only slightly at heating rates of over 50 ℃/s.The recrystallization microstructure has a strong texture,which is a result of the sharpening of the favorable{111}//ND(normal direction)texture components orγ-fiber.With increasing heating rates,the peak value of f(g)ofγ-fiber decreases from17 to9.The yield and tensile strengths increase gradually as the heating rate increases from4 to 50℃/s,but remain almost unchanged at heating rates of more than 50℃/s. The total elongation and uniform elongation increase gradually as the heating rate increases from4to100℃/s,but decreases slowly for heating rates higher than100℃/s.As the heating rate increases from4to100℃/s,the plastic strain ratio of the steel decreases from2.8to2.2;however,it increases to2.9for heating rates above100℃/s.The strain hardening exponent remains unchanged at 0.27in all annealing cycles.     

Thermal transients during processing of materials by very high power ultrasonic additive manufacturing

Dynamic recrystallisation at interfaces has been suggested as the bonding mechanism in the joining of metallic tapes, during very high power ultrasonic additive manufacturing. To understand the reasons for such occurrence of dynamic recrystallization, thermal transients from the interface regions were recorded during processing of aluminum alloy (3003 and 6061 series) and 11 000 copper tapes under similar conditions. Measurements in 3003 Al were also carried out for different processing parameters. Measured peak temperatures were seen to increase with increase in shear strength of the material and ultrasonic vibration amplitude. The observations have been rationalized based on interfacial heating at asperities due to adiabatic plastic deformation.     

重型工件烘干干燥设备分析与改进

进行了铸铁工件喷涂后烘干固化设备的温度曲线分析,指出了保温设备中热风循环系统中设计不合理的地方。     

水源热泵技术在船舶供暖空调上的应用研究

船舶作为能源消耗和排放大户，节能减排形势十分严峻，对其进行节能减排技术改造，具有重要的现实意义。在这种背蒂下，以高效、节能、环保为主要特征的绿色能源系统一水源热泵，取代传统的船舶供暖空调装置技术应运而生。本文通过对水源热泵技术系统的研究，结合某测量船使用水源热泵供暖空调装置的实际状况，进行实地测试、统计、计算，对其技术原理、节能指标、经济效益、市场潜力等方面进行综合分析，为在北方内河船舶上全面推广该技术提供理论和实践的依据。     

Criteria for use of groundwater as renewable energy source in geothermal heat pump systems for building heating/cooling purposes

Environmental protection measures are conducted directly by the use of renewable energy sources. The energy development of cities in Europe is aimed at the sustainable use of renewable energy sources in order to achieve the substitution of fossil fuels and the reduction of the hazardous gas emission into the atmosphere. Geothermal resources of medium and low enthalpy in Europe being used for obtaining heat energy are providing about 6600 MW_t, currently having the growth trend of 50 MW_t annually. The use of geothermal low enthalpy, namely of subgeothermal groundwater resources, has even higher annual growth rate, and if such a trend is kept till the year 2010, the produced energy will amount about 8000 MW_t. Criteria of the groundwater use as a hydrogeothermal energy resource in heat pumps are complex, and they deal with aspects of incoming temperatures and groundwater quantities. The precise limit temperature of groundwater that would separate the direct use of geothermal energy (only by the use of heat exchangers), and indirectly by the use of a heat pump has not been determined in the professional and scientific practice of Serbia so far. Taking into account that relatively small number of new flat is being built in Serbia nowadays, if we want to save energy it is necessary to carry out the energy reconstruction of the existing flats whose number is estimated to be more than 2.8 million. By the application of subgeothermal energy and the use of heat pumps, energy consumption would be significantly reduced.     

Effect of potato presence on the degradation of extra virgin olive oil during frying

This work investigates the effect of potato presence on the degradation of extra virgin olive oil (EVOO) during repeated frying. For this reason the performance of EVOO during frying was compared with its performance during heating at frying temperatures. In order to make meaningful comparisons the temperature profiles obtained during the frying experiments were replicated during the heating experiments by means of a high energy exchange rate cooling/heating system. The effects of potato‐to‐oil ratio (1/7 and 1/35 kg_potatoes/L_oil) and number (N) of batches (N = 0, 1, 0, 20, 30, 40) were examined. EVOO was analysed using high performance size exclusion chromatography (HPSEC). It was found that polymerisation products increased linearly during frying and heating and that they were not affected by potatoes presence at low ratio. The effect of potato presence became statistically significant (yet not remarkable) at the high ratio. Decomposition products increased during frying whereas they decreased during heating.     

防腐蚀FRP板材在钢结构建筑上的应用

对耐腐蚀FRP板材所要求的基体树脂、纤维性能进行介绍。总结了在不同行业应用耐腐蚀FRP板材的形式。最后,对采用FRP板材保护的墙面、屋面的常用类型和形式进行了介绍。     

陶瓷材料微波加热特性计算分析

为更清楚和准确了解材料微波加热行为,提出了球形陶瓷材料微波加热升温过程的一个数学模型。用有限差分隐式格式推导了离散方程,通过编程进行了数值迭代计算,得到了Si C陶瓷球加热升温过程动态温度曲线,并分析了其加热基本特性。在此基础上,探讨了材料热导率和微波功率的影响。计算结果表明,微波体积加热效应决定了物体内部温度分布比较均匀;与普通加热方式不同,微波加热的物体内部温差随时间逐渐增加,加热初期温差比较小,这一特性决定了微波加热特别适合快速加热;对每一微波功率,有一个最大稳定温度值,因此烧结不同材料,所用微波功率应不同。材料热导率越大,物体内部温度分布越均匀,但能达到的稳定温度越低;微波功率越大,物体能达到的稳定温度越高,但物体内部温度均匀性越差,因此,为保证材料均匀烧结,不宜用大功率。