Off-Site Exposure to Respirable Aerosols Produced during the Disk-Incorporation of Class B Biosolids

Field experiments were conducted at a Class B biosolids land application site in central Arizona to measure, model, and source-track the off-site transport of aerosols emitted when biosolids were disk-incorporated into soils. Real-time PM10 monitoring provided time-resolved aerosol information sufficient for verifying both off-site concentration and off-site exposure time model results. Under the conditions considered and at a distance of 165?m from the aerosol source, biosolids disk-incorporation resulted in an intermittent exposure to biosolids-derived aerosol concentration between 15 and 40?μg/m3 and an inhalable biosolids dose between 2 and 8?μg. Transport modeling predicted that these doses will decrease with increasing wind speed. In addition, three DNA sequence-based biosolids source tracking methods were applied to aerosol samples and confirmed the presence of biosolids in aerosols at 5, 65, and 165?m from the aerosol source. Field measurements and modeling indicate that the nature of biosolids-derived aerosol exposure is a series of intermittent high concentration puffs, rather than a continuous low concentration.     

Approach for Overcoming Numerical Inaccuracy Caused by Load Discontinuity

It was found that the discontinuity at the end of an impulse will lead to numerical inaccuracy as this discontinuity will result in an extra impulse and thus an extra displacement in the time history analysis. In addition, this extra impulse is proportional to the discontinuity value at the end of the impulse and the size of integration time step. To overcome this difficulty, an effective approach is proposed to reduce the extra impulse and hence the extra displacement. In fact, the novel approach proposed in this paper is to perform a single small time step immediately upon the termination of applied impulse, whereas other time steps can be conducted by using the step size determined from accuracy consideration in period. The feasibility of this approach is analytically explored. Further, analytical results are confirmed by numerical examples. Numerical studies also show that this approach can be applied to other step-by-step integration methods. It seems that to slightly complicate the programming of dynamic analysis codes is the only disadvantage of this approach.     

Perceptual Temporal Quality Metric for Compressed Video

This paper presents a metric to quantify frame loss according to the impact on perceived temporal quality. This metric particularly aims at measuring the temporal quality degradation caused by both regular and irregular frame loss. Experimental results with subjective viewing demonstrate high performance on prediction of perceptual temporal quality.     

鞍钢现有人造富矿产能及1600万t/a生铁规模的合理炉料结构的探讨

简要介绍了鞍钢现有人造富矿生产能力，分析了鞍钢生产1600万t／a生铁所需要的炉料数量、品种和质量，并提出了解决炉料缺口的方法和措施。     

薄板坯连铸生产SS400钢工艺技术研究

对唐钢薄板坯连铸机生产的SS400钢的生产工艺进行了分析,认为薄板坯连铸机生产的SS400钢,在采取了精炼站在线定氧,将钢水全氧控制在25×10~(-6)左右,同时连铸采取保护浇注和轻压下等技术后,能够确保薄板坯连铸SS400钢的顺利浇注,轧制的板带材表面质量良好,机械性能符合要求。     

钻井液振动筛叠层筛网透筛率的研究

从理论上详细论述了钻井液振动筛叠层筛网对固相颗粒分离的影响 ,首次提出用透筛率的概念定量地描述这一影响 ,并进行了实例计算。研究表明 ,当上下层筛网随机叠加时对透筛率的影响有以下几种情况 :(1)当上下层筛网开孔尺寸相除的余数为零 ,任意组合叠层筛网的透筛率分别为某一常数 ;(2 )上层筛网目数一定时 ,下层筛网目数越大 ,则透筛率越小 ;(3)上下层筛网的目数相差越小 ,透筛率越小 ;(4 )任意目数的上下层筛网随机叠加后 ,其透筛率仅在一个小范围内变化 ,因此任一叠层筛网有其固有的透筛率属性。     

世界各国(或地区)推进RFID的策略

介绍了一些国家和地区发展RFID的政策和推进措施，总结了各国发展RFID的共性。     

Applying CIM technology to image factories

Image processing allows the automation of the business transaction, turning “paper factories” into “image factories.” This burgeoning new area of computerization needs new paradigms, theories, and methods to maximize its effectiveness at cutting time and costs. This paper investigates what this new area of computerization can gain from CIM technology. It examines the similarities between the processing of computer images in a paperless business environment and the processing of materials into products in the manufacturing plant. These similarities will allow us to apply mature, well-tested CIM techniques to emerging image factories.     

Ozonation of CI Reactive Black 5 using rotating packed bed and stirred tank reactor

This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry     

难处理金矿石加石灰焙烧焙砂中CaS的消除

介绍了用空气氧化预浸加石灰焙烧焙砂中的CaS，以消除其对金氰化的影响。预浸后金的氰化浸出率可从58％提高到80％以上。