矿用空气幕控制风流流动技术研究

分析了国内外矿井风流控制技术及矿用空气幕的研究进展,介绍了矿用空气幕的几种布置形式,阐述了多功能矿用空气幕在控制风流反向、控制风流循环、控制风流短路、增加或减少巷道风量等方面的作用及效果。应用结果表明,矿用空气幕安装在巷道侧壁的硐室内,不仅能有效控制矿井风流的流动,而且不影响运输巷道内的行车和行人,在地采矿山具有广阔的推广应用前景。     

Variations of Thermal Conductivity of Insulation Materials Under Different Operating Temperatures: Impact on Envelope-Induced Cooling Load

The thermal and energy performance of buildings depends on the thermal characteristics of the building envelope, and particularly on the thermal resistance of the insulation material used. The performance of the thermal insulation material is mainly determined by its thermal conductivity, which describes the ability of heat to flow across the material in the presence of a differential temperature. The value of the thermal conductivity of a particular material is subject to variation, due to changes in both moisture content and temperature. In reality, thermal insulation in buildings is exposed to significant and continuous temperature variations, due to varying outdoor air temperature and solar radiation. However, when calculating cooling loads or performing energy analyses for buildings, most designers, if not all, use published or manufacturer-supplied values of thermal conductivity, which are normally evaluated at 24°C according to the ASTM standards. Currently, many types of insulation materials are produced in Saudi Arabia, but not enough information is available to evaluate their performance under the prevailing climatic conditions. The objective of this paper is to present the results of a study that investigates the relationship between the temperature and thermal conductivity of various types of locally produced insulation materials. Additionally, the impact of thermal conductivity variation with temperature on the envelope-induced cooling load for a theoretically modeled building is quantified and discussed. Results are expected to clarify the issue of thermal conductivity dependence on temperature and lead to a more accurate assessment of the thermal and energy performance of buildings.     

热冷循环下外墙外保温系统耐候性能数值模拟

为了从墙体温度稳定性角度探讨外墙外保温系统的耐候性能,利用ABAQUS有限元软件,对采用胶粉聚苯颗粒保温浆料涂料饰面的外墙外保温墙体,建立三维瞬态热结构耦合模型并进行数值模拟分析,计算其在热冷循环下不同功能层的实时温度场、热应力及位移分布.计算结果表明:在热冷循环过程中,涂料饰面层温差最大,墙体内饰面层温差最小,日变化量在2℃以内;沿墙厚方向保温浆料层温度变化率均大于其他材料.涂料饰面层经历拉压循环,低温时受拉,高温时受压;在整个循环过程中基层墙体内表面始终受压,基层墙体内应力变化幅度较小.与保温浆料层相比,界面砂浆层所受应力较大,保温浆料层应力几乎为零.沿墙厚方向最大位移出现在保温浆料层.      

Motivational aspects of individual variation in response to nestboxes by laying hens

Laying hens, Gallus gallus domesticusshow individual variation in pre-laying behaviour including their ultimate choice of nest site. In housing systems with nestboxes, the majority of hens make a small number of long visits to nestboxes and lay their eggs therein, but some hens make many short visits and occasionally lay outside the nestbox. We investigated the motivational basis of this individual variation using six consistent hens which always laid in nestboxes and six inconsistent hens which sometimes laid outside nestboxes. Each hen was housed in a pen (containing either no nestbox, a semi-enclosed nestbox or an enclosed nestbox) with access to a ring-shaped tunnel which increased the opportunity to perform locomotor activity. Access to the tunnel could be restricted by narrowing the doorway to 140, 125, 110 or 95 mm (compared with a mean hen width of 114 mm). In trials with no nestbox, there was no difference in the pre-laying behaviour of consistent and inconsistent hens. Narrowing the doorway reduced the number of visits to the tunnel, but all hens persisted in visiting the tunnel and doorwidth had no effect on time spent therein. With both designs of nestbox, however, inconsistent hens visited the tunnel more often than consistent hens prior to oviposition, and continued to pass the narrowest doors to enter the tunnel, whilst consistent hens would not pass doors of 110 or 95 mm. After oviposition, there was no difference in the two groups' behaviour in any treatment and no hens would pass doors of either 110 or 95 mm to visit the tunnel. Individual variation in nest-site choice, therefore, appeared to result from different perception of nestboxes rather than lower nesting motivation. Inconsistent hens worked as hard as consistent hens to perform pre-laying locomotion, but appeared to be less responsive to the cues provided by nestboxes than consistent hens, because they persisted with pre-laying locomotion when provided with either design of nestbox.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour     

气隙对高炉炉缸凝铁层的影响

摘要：高炉炉缸内衬表面形成稳定的凝铁层将延长高炉寿命。采用三维数值模拟探讨了凝铁层的导热系数及炉缸区域气隙对高炉传热体系的影响;数学模型中凝铁层的导热系数采用修正后的结果,发现冷面附近的计算温度与热电偶实测温度不符,推断有绝热层（气隙）的存在。当绝热层（气隙）厚度在0.5～1mm时,计算温度与实测温度（正常炉况下）一致。通过引入绝热层（气隙）的概念对现有的传热模型进行了修正,绝热层（气隙）的厚度变化将影响炉缸凝铁层的厚度;发现当绝热层（气隙）厚度达到6.5mm时,凝铁层刚好完全消失;即绝热层（气隙）厚度的变化是影响凝铁层消失的主要因素,进而影响高炉长寿。     

隧道通风过程中空气湿热状态变化研究

隧道及巷道等地下工程在施工及运营阶段需要以自然或机械通风设施等方式进行通风,以保持充足的新鲜空气量,并维持其内人员的舒适感。当前大多研究集中在隧道通风过程中的空气质量以及烟雾透过率,而较少关注通风过程中空气的湿热状态的变化。以热力学及流体力学的基本理论为基础,研究地下隧道长距离、大规模地下输送新鲜空气过程中,隧道内空气湿热状态的变化。通过论证,在经过隧道长距离输送后,空气湿热状态参数发生较大变化。这说明,空气在地下输送过程中,尽管有风机做功以及摩擦生热过程,但在恒温层的保温作用下,温度只会略有上升;而湿度则会升至饱和状态。这将对地下储库、地下采矿等地下工程的空气调节系统设计研究工作有一定指导意义。     

Thermal Insulation Systems for Bioremediation in Cold Regions

Bioremediation of petroleum-contaminated soils in cold regions is hampered by low temperatures, frozen soils, and short summers. Extreme environmental conditions limit remedial efforts to a few technologies. Bioventing and combined air-sparging and soil vapor extraction have shown promise in subarctic regions. Expensive thermal desorption or encapsulation of organically contaminated soil is practiced in arctic Alaska and Canada, in lieu of successful bioremediation. Thermal insulation systems have recently been developed for innovative bioremediation efforts in cold regions. Commercially available insulation, electrical heating elements, and construction materials have been uniquely packaged to enhance bioremediation at two petroleum-contaminated sites in Alaska. Thermally enhanced bioventing successfully remediated hydrocarbon contamination in the vadose zone at a subarctic site within two years. Preliminary results from an oxygenated and fertilized biopile, actively warmed and covered with a thermal insulation system, shows promise at an arctic site. A guide for thermal insulation system design for bioremediation application in cold regions is developed.     

热风管道及其保温层的同步设计法

利用热经济学的基本原理,对热风管道同热风的输过程进行了分析,得到了热风管道的年总费用方程,该方程可用于分析热风管道管径、保温层厚度等因素对年遇用的影响;提出了热风管道及其保温层的同步设计法,从降低热风输送年总费用的角度出发,得到了最佳管径和最佳保温层厚度的计算公式,其结果可供工程设计参考。     

上向水平分层充填采矿法中段通风系统的优化研究

针对金属矿山上向水平分层充填采矿法中段通风系统设计和管理中的采场风量分布不均、辅扇风机设置不当等问题，借助Ventsim软件构建中段通风模型来分析中段通风风量的分布规律。结果表明：当风机设置在一侧时，中段两端位置采场分配风量较多，中部位置采场分配风量少。同时，对建立的中段通风模型进行风窗设置方案对比，发现风窗设置数量越多，风量可调控范围越大，且在两端分别设置较仅在靠近集中回风段设置效果更好。当在07^#, 06^#和01^#采场回风端分别设置风窗，且风窗面积呈一定增大关系时基本可保证模型中各采场分配风量符合要求。以大尹格庄金矿为例，在构建通风系统整体三维模型的基础上，利用仿真模拟功能，对2号矿体-676 m中段通风系统进行优化设计，作业地点的风量合格率由25%提高到100%。     

The relationship between insulin bioactivity and structure in the NH2-terminal A-chain helix

Old females are compared to young females for the purpose of studying the difference in comfort caused by the environmental variables of temperature and humidity as well as the form of clothing. Eight experiments were performed in three settings: (a) 30 degrees C R.H.80%; 30 degrees C R.H.45%; and 20 degrees C R.H.45%. The ages of the subjects range from 62 to 68 (Mean = 65.17, S.D. = 1.68) among old females and from 20 to 23 (Mean = 20.83, S.D. = 0.76) among young females. The following results were obtained: (1) The young females were sensitive to hot temperatures, while the old females were not. On the other hand, the old females were more sensitive to cold temperatures, under 20 degrees C R.H.45%, than the young females. In temperatures under 30 degrees C R.H.80%, the heat radiation from the young females was higher than that of the old females. Under 20 degrees C R.H.45%, the heat radiation from the old females was higher than from the young females. The old females are thought to decline in physiogenic function due to enduring both hot and cold temperatures. (2) The correlation between the temperature in clothes and comfort among the old females is not different from the same correlation among the young females. This conclusion agrees with previously published studies of the young females. (3) Skin temperature and bloodstream are measured, according to clothing form. As a result, a long skirt is the highest in thermal insulation, long pants the next highest, and a short skirt is the lowest. (4) The effect of thermal insulation provided by a lap robe was tested in both groups. The lap robe was found to be more effective for the older group than the younger in temperatures under 20 degrees C R.H.45%. Hence, the role of clothes in offsetting for the decline in the thermoregulation function that compensates for environmental change is more important for old females than for young.     

Computer Simulation of Thermal and Stress-Strain State of Blast Furnace Tuyeres

Metallurgist - A research has been conducted to study the effect of the thickness of a thermal insulation insert inside the air passage of a blast furnace tuyere and the size of the air gap...     

盾构在矿山法隧道内进出洞施工关键技术

地铁等区间隧道两端多为强风化的岩层或残积土,中间较深段常遇到未风化或微风化的高强度岩层,单靠盾构法施工难以完成,多采用"矿山法+盾构法"施工。以深圳地铁某区间隧道为例,详细介绍了"矿山法+盾构法"工法中盾构在矿山法隧道内进出洞施工技术,提出了解决施工关键技术的措施,为这种新型复合工法的推广提供了良好的借鉴。     

Modeling incubation temperature: the effects of incubator design, embryonic development, and egg size

A simple model to describe the relationship between the temperature of the developing embryo, incubator temperature, embryo heat production, and thermal conductivity of the egg and surrounding air is presented. During early incubation, embryo temperature is slightly lower than incubator temperature because of evaporative cooling. However, from midincubation onwards, metabolic heat production from the embryo raises embryo temperature above incubator temperature. The extent of the rise in embryo temperature depends on thermal conductivity, which, in turn, is mainly influenced by the air speed over the egg. The importance of air speed and restrictions to air flow within artificial incubators is discussed. Exact determinations of optimum incubation temperatures from studies reported in the literature are difficult because only incubator temperatures are reported. Embryo temperatures can differ from incubator temperature because of differences in thermal conductivity between different incubation systems and differences between incubators in their ability to control temperatures uniformly. It is suggested that shell surface temperatures are monitored in experiments to investigate temperature effects to allow consistent comparisons between trials. Monitoring shell temperatures would also make it easier to translate optimum temperatures derived in small experimental incubators to the large commercial incubators used by the poultry industry. The relationship between egg temperature, the metabolism of the developing embryo and egg size is discussed.     

Acute carpal tunnel syndrome

Although the carpal tunnel is open at both ends, it has the physiologic properties of a closed compartment bounded by synovium proximally and distally. When the intracarpal canal interstitial pressure rises above a critical threshold pressure, capillary blood flow is reduced below the level required for median nerve viability. Acute carpal tunnel syndrome is recognized frequently as occurring secondary to wrist trauma and infrequently due to a variety of infectious, rheumatologic, and hematologic disorders. This condition warrants prompt recognition and the treatment is early carpal tunnel release.     

Effect of Slurry Coating on the Resistance of Thermal Insulation Insert in Blast Furnace Air Tuyere

Metallurgist - Air tuyeres account for 30% of all heat losses in a blast furnace. One of the methods for lining a tuyere from the air passage side is to use a thermal insulation insert. However,...     

Measurements of Air Leakage through Revolving Doors of Institutional Building

Exterior doors and entrances of nonresidential buildings are major sources of energy losses caused by air infiltration or exfiltration due to the frequent use of doors and the pressure difference across each door, created by the wind, stack effect, or ventilation systems. Information regarding the air leakage characteristics of manually or power-operated revolving doors is available in the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE) publications, based on studies carried out in the 1950s and 1960s. This paper presents results from a recent study carried out to investigate the air leakage characteristics of four revolving doors of a large institutional building in Montreal. These results are compared with data available in ASHRAE publications, as well as with the specifications of the Model National Energy Code of Canada for Buildings and ASHRAE Standard 90.1. The impact of the quality of seals on the annual heating costs is also evaluated.     

Analysis of spatial distribution of grain orientations in deformed 01 ЮT steel

The influence of the rolling parameters on microstructure and texture formation over 01 ЮT steel strip and on its capacity for profound extension is investigated. It is found that the capacity for profound extension in a 01 ЮT steel sample deformed in the austenitic state and cooled in air may be attributed to the higher concentration of small-angle boundaries and special boundaries Σ3 60° <111> than in steel for which rolling ends at subcritical temperatures.     

Microwave Technology for Treatment of Fume Hood Exhaust

CHA Corporation installed a fume hood adsorber (scrubber) unit onto an operating fume hood and microwave regeneration system in the Safety and Risk Management Building at the Advanced Technology Park in Bozeman, Montana. The microwave-based fume hood exhaust purification process is designed to capture hazardous air pollutants in the fume hood exhaust using granular activated carbon (GAC) and natural zeolite, and subsequently either recover or destroy desorbed pollutants by microwave energy during regeneration of the saturated adsorbents. Onsite testing of this prototype microwave system was conducted using a variety of air borne pollutants including toluene, ethyl acetate, methylene chloride and hydrochloric acid. Test results showed that microwave energy, at a frequency of 2,450 MHz, restored the original adsorption capacity of saturated GAC and saturated natural zeolite. The results also demonstrated that microwave-induced catalytic oxidation was capable of providing oxidation efficiencies greater than 99% with oxidation temperatures below 100°C.     

Capillary tube resistive thermal cycling

A system that performs rapid thermal cycling of microliter and smaller liquid volumes inside glass capillary tubes that have an optically transparent thin film of indium-tin oxide (ITO) covering the exterior is described. The ITO film acts as both a heater and a temperature sensor, while cooling is accelerated with forced air. Unlike existing batch-mode thermal cycling systems, this system allows control over each sample's temperature profile. Temperature transition rates of 44 degrees Celsius per second during heating and 15 degrees Celsius per second during cooling have been achieved, allowing successful polymerase chain reaction (PCR) experiments to be performed in 20 min. Capillary external temperature can be regulated typically to within +/- 0.25 degrees Celsius, and peak temperatures more than 800 degrees Celsius have been demonstrated. Capillary internal (sample) temperatures at present are controllable typically to within 2 degrees Celsius. The resistive film can be used as a temperature sensor, and the optical transparency of the thin-film coating could permit fluorescent monitoring of the sample during thermal cycling, making this method well suited for real-time quantitative PCRs.     

Porous Surfaces Via Impinging and Solidifying Molten Hollow Melt Droplets on Substrates

We numerically study impingement and solidification of a molten hollow droplet onto a surface during thermal spray coating process. In the impingement model transient flow during the hollow droplet impact, subsequent spreading and solidification, and air entrapment are considered using the volume of fluid surface tracking method coupled with the solidification model within a one-domain continuum formulation. A phenomenon of counter liquid jetting is observed which causes large air entrapment and porous deposited layer. This will have potential prospects in improving the thermal insulation properties of surfaces in turbine blades, engine components applications.