清梳联合机工艺技术与设备创新探讨

通过利用AFis纤维检验仪对清梳联各单机在制品的测试结果 ,得出了清梳联工程中棉结、杂质的变化规律 ,并对清梳联工程中清棉打手的组合结构、清梳除杂分配、清梳联短绒控制、生条定量控制、排尘、滤尘与空调系统等重要问题进行了讨论。     

Reduction of Particle Reentrainment Using Porous Fence in Front of Dust Samples

Wind tunnel experiments were conducted to measure the emission factor of particle reentrainment from a dust sample with or without a porous fence. The effect of wind velocity, fence porosity, and distance between the fence and the dust sample on the emission factor was studied. A 20% porous fence was found to be effective for reducing the particle reentrainment at a low wind velocity of 5?m/s. When the wind velocity was increase from 7 to 15?m/s, the results show that the particle reentrainment can also be reduced in a certain region behind the fence (x/H<4,?x=distance between fence and sample; H=fence height) for the 20% porous fence. A linear multivariable regression model was fitted to the logarithmically transformed experimental data. The good fit of the regression model makes it possible to estimate emission rate as a function of the dimensionless distance (x/H), the wind velocity, and the elapsed time.     

Survival of the House Dust Mite,Dermatophagoides farinae,at High Temperatures (40–80°C)

Abstract Experiments were conducted to evaluate the survival time of randomly selected female D. farinae exposed to temperatures from 40 to 80°C and relative humidities (RHs) between 10 and 90%. Significant temperature effects were found on the length of time mites can survive under those conditions. The time needed to induce 100% mortality for female D. farinae held at 40°C varied between 39 and 84 h. At 70 and 80°C, all mites died within 5 minutes. At 50°C and above, RH had little influence and temperature alone was the determining factor for mite survival. The length of survival time decreased precipitously between 40 and 50°C, suggesting that a loss of physiological integrity of female D. farinae probably occurred in this range. The results of this study indicated that the technique of raising temperatures to above 40°C for a short duration can be used to reduce living house dust mite populations in homes significantly.     

Indoor Environmental Risk Factors for Respiratory Health in Children

Abstract The indoor environment of 80 houses in the Latrobe Valley, Victoria, Australia was assessed during six visits performed bi-monthly over a period of one year. Children between 7 and 14 years of age residing in the houses were included, resulting in 148 study children, 53 of whom were asthmatic. A respiratory health questionnaire was completed and skin prick tests performed. Significant risk factors for asthma were: exposure to a gas stove (OR=3.15, 95% CI 1.28-7.72), and indoor pets (OR = 2.68, 95% CI 1.07-6.70). Exposure to airborne Aspergillus spores (+10 CFU/m³, OR=1.51, 95% CI 1.05-2.18) was a risk factor for atopy, while exposure to a gas stove (OR=2.32, 95% CI 1.04-5.18) was a risk factor for respiratory symptoms. In conclusion, exposure to gas stoves, fungal spores and pets in the home were identified as statistically significant risk factors for respiratory health in children.     

综采放顶煤开采的安全技术

经过十几年的放顶煤开采的实践,中国较好地解决了放顶煤开采的防瓦斯、防火和防尘问题,使该技术逐渐走向成熟,并从中获得了效益。     

焦化地面站除尘风机变频改造纪实

本文介绍了高压变频器在古县正泰焦化地面站除尘风机上应用情况。改造结果表明,采用高压变频器对焦化地面站除尘风机设备进行调速节能改造,具有较高的经济效益和社会效益。     

大功率高压变频器在烧结机头除尘器上的应用

本文介绍了国产超大功率高压变频器在济钢的成功应用情况,表明了我国变频器行业在大功率高压变频器领域的自主研发能力已进入国际一流水平。烧结机主抽风机使用国产变频器进行节能运行,具有投资省,回收期短,运行效率高等特点。     

Effectiveness of coal mine dust control: A new technique for preparation and efficacy of self-adaptive microcapsule suppressant

This study aims to make full use of the agricultural waste peanut shells to lower material costs and achieve cleaner production at the same time. Cellulose nanofibrils (CNF) extracted from peanut shells were mixed with acrylic acid (AA) and dimethyl diallyl ammonium chloride (DMDAAC) to prepare a new type of capsule core (dust suppressant). Then, the self-adaptive AA-DM-CNF/CA microcapsules were prepared under the action of calcium alginate. The infrared spectroscopy and X-ray diffraction analysis results suggest that AA, DMDAAC and CNF have experienced graft copolymerization which leads to the formation of an amorphous structure. The scanning electron microscopy analysis results demonstrate that the internal dust suppressant can expand and break the wall after absorbing water, featuring a self-adaptive function. Meanwhile, the laser particle size analysis results show that the microcapsules, inside which the encapsulated dust suppressant can be observed clearly, maintain a good shape. The product performance experimental results reveal that the capsule core and the capsule wall achieve synergistic dust suppression, thus lengthening the dust suppression time. The product boasts good dust suppression, weather resistance, degradation and synergistic combustion performances. Moreover, this study, as the first report on the development and analysis of dust-suppressing microcapsules, fills in the research gap on the reaction mechanism between dust-suppressing microcapsules and coal by MS simulation. The proposed AA-DM-CNF/CA dust-suppressing microcapsules can effectively lower the dust concentration in the space and protect the physical and mental health of coal workers. In general, this research provides a new insight into the structure control and performance enhancement of dust suppressants. Expanding the application range of microcapsules is of crucial economic and social benefits.     

中外粉尘监测技术的比较

通过分析粉尘的危害指出进行粉尘监测的意义,讨论了国内外粉尘监测技术方面的研究进展。在法律法规实施、监测仪器精度、监测仪器创新和监测防护措施等方面对我国与国外发达国家进行了比较,找出存在的主要差距,为我国未来粉尘监测技术领域的发展指明了方向。     

Predicting dust emissions – Experimental study compared to coupled DEM/CFD simulations using a reference test bulk material

The awareness of dust emissions is crucial regarding safe industrial processes, environmental protection and health care. For this purpose, closely linked experimental and numerical investigations are performed. This work presents the results of an experimental study which is used for the calibration of a modelling framework based on the Discrete Element Method (DEM) coupled with Computational Fluid Dynamics (CFD) and applied for the calculation of dust emissions for predictive purposes. The key objective of the approach is to come up with a dust source term which enables to describe and to quantify the release of particle emissions. For the presented experimental study, a wind tunnel and a rotating drum setup, which cover various handling types of bulk materials, are used in order to gain data about parameters having an impact on the dust release. The special feature of the investigations is the use of a reference test bulk material which represents a bulk material in its generally main fractions, the fine and the coarse material, keeping the discrepancy between experiments and simulations low. With the help of the experimental results the calibration of the simulation model was carried out and followed by a comparison.