多功能空调热水器系统的改进

为了解决多功能空调夏季单独制热水时,室外风机频繁启停的问题,设计了一种改进的多功能空调热水器。通过改进多功能空调热水器系统的室外风冷换热器,改变了风机的输入电压和转速,调节了风冷换热器的吸热量,使其在不同季节的各种模式下,均能够高效稳定的运行。通过实验找出了压缩机和风机稳定运行的临界输出电压,得到了与节流阀各个开度相对应的系统COP。与未改造前的系统相比,多功能空调热水器系统加入了变压器之后,系统的稳定性增加。在室外环境温度为32℃,节流阀开度为0.4,变压器输出电压为160 V时,可达到夏季单独制热水模式的最佳工况,其COP为4.68。     

以毛细管为节流装置的CO_2小型热泵热水器实验研究

介绍以毛细管为节流装置跨临界CO2热泵热水试验系统。实验研究了不同气冷器进水温度下系统的COP及其变化、气冷器沿管长水温温升梯度变化。分析了不同环境温度下制冷剂充注量对系统高压侧压力的影响。可以得出:以毛细管做节流装置也可以得到较高的COP;气冷器水温在高温CO2进口段温升幅度最大;系统对环境温度的变化很敏感,环境温度较低时要想得到合适的高压侧压力,制冷剂的充注量要比环境温度高时多。     

空气源热泵热水器制冷剂充注量的试验研究

为了研究制冷剂充注量对空气源热泵热水器性能的影响,对一台充注非共沸混合制冷剂的试验机组进行不同充注量的试验,并根据试验数据分析充注量与制热量、耗功、吸排气温度、压缩比和COP的关系。结果表明:制冷剂充注量从1.95 kg增加到2.5 kg时,制热量和耗功分别增加3.41%和3.03%,COP几乎相同;充注量对压缩机的吸、排气温度和压缩比的影响很明显;为了保证机组运行的稳定安全性,最佳充注量应为2.3 kg。     

太阳能复合能源空调热水系统中热泵系统换热性能的试验研究

通过将太阳能热水系统和空调热泵系统结合,设计出太阳能复合能源空调系统.针对该新型系统中的热泵空调热水子系统进行研究,在标准工况下,分别对该系统的3种模式下的换热性能进行试验,数据分析结果表明该系统比传统系统更为高效的,其单独制冷模式下系统最高COP可达5.34,单独热水模式下的静态加热系统COP可达5.78,制冷兼热水模式下系统COP可达4.5.     

热泵型空调器运行特性的实验研究

用空气焓差实验法,在制冷工况下对一台热泵型空调器进行最佳充注量的实验研究,同时,分别在制冷工况和制热工况下测量冷凝器和蒸发器管壁的温度分布。实验结果表明,空调系统中存在一个最佳制冷剂充注量,使得空调系统的制冷量和能效比达到最大值。根据实验结果,分别给出在制冷工况和制热工况下进行冷凝器和蒸发器换热计算时,制冷剂与管壁之间的平均温差。     

带废热回收的家用热泵热水装置实验研究

为回收家庭洗浴废水中的废热,提高能源利用率,本文设计了一种带废热回收的热泵热水装置,并通过搭建实验台研究了该装置制取热水的循环性能。在进水温度为16℃,出水温度为36～46℃时进行实验测试,研究制热量、制热COP、压缩机功率、出水量等参数随出水温度和制冷剂充注量的变化规律。实验结果表明:适当提高制冷剂充注量有利于制热量、制热COP的稳定,在最小的制冷剂充注量为1.4 kg时,获得最大制热量为7.9 k W,制热COP为7.7;在出水温度为36～46℃,随出水温度的升高,压缩机功率增大,出水体积流量下降。该装置能够有效回收废水中的热量,制热量稳定在约7.5 k W,制热COP大于6.0。     

变容量家庭能源中心制冷兼制热水模式性能实验研究

现有的多功能热泵机组的制冷兼制热水模式存在结构复杂、能量控制难以满足需求等问题,为此,提出基于数码涡旋压缩机的变容量家庭能源中心系统,并确定制冷兼制热水模式的机组性能系数计算方法。通过实验对比分析制冷兼制热水模式和单独制冷模式的性能,结果表明:与单独制冷模式相比,制冷兼制热水模式的制冷量有所衰减,但机组的总能量输出和性能系数分别提高了17.3%和36.8%。实验研究制冷兼制热水模式在水箱初始温度、不同压缩机负荷和不同环境温度下的动态特性和性能表现。通过分析该模式在各种工况下的性能变化规律,总结控制策略,可保证该模式的安全高效运行。     

制冷剂充注量及毛细管长度对空气源热泵热水器性能的影响

对一台空气源热泵热水器进行制冷剂充注量和毛细管长度的性能匹配试验。试验结果表明:在试验所取的制冷剂充注量和毛细管长度范围内,随着制冷剂充注量增大,制热量和COP先增大后减小,功耗则不断增大;随着毛细管长度增大,制热量、功耗和COP均是先增大后减小;当系统在最佳匹配时,COP达到4.14 W/W。制冷剂充注量和毛细管长度对制热量的影响相对较大,对功耗的影响相对较小,当制冷剂充注量和毛细管长度发生变化时,在差异程度最大时,制热量的变化率比功耗的变化率分别高183.3%和82.4%;在制冷剂充注量较大时,COP会明显下降。当制冷剂充注量较大时,在运行前期的水温增长速率比制冷剂充注量较小时高,在运行后期(约60 min以后)反而比较低。     

带外经济器的喷射节流制冷装置的研究

由于在传统制冷空调循环中的节流阀造成了大量能量损失,故现在以喷射器代替节流阀,并配合使用外经济器来达到节能效果。通过与不同制冷循环在不同工况下的对比与研究,最终确定带外经济器的喷射节流制冷循环所适合的制冷工况。     

带外经济器的喷射节流制冷装置的研究

在传统制冷空调循环中,节流阀造成了大量能量损失。现在以喷射器代替节流阀,并配合使用外经济器来达到节能效果。通过与不同制冷循环在不同工况下的对比研究,最终确定带外经济器的喷射节流制冷循环所适合的制冷工况。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.