某电厂球磨机噪声控制

对某电厂球磨机噪声进行了现场数值测定和频谱分析,针对其宽频特性选择新型隔声罩噪声控制设计和装置结构,取得了很好的隔声效果,噪声值达到了0级标准即安全作业标准,受到企业和车间工作人员的好评。     

MB1870型球磨机噪声治理

１　前言　　球磨机应用于化工、水泥等行业,运转时排放的声源噪声达１０８ｄＢ（Ａ）左右,不仅生产操作者难以承受,而且对周围环境造成严重污染。为了降低设备噪声,我们采用约束型粘弹阻尼结构减震,并结合吸声、隔声、消声技术综合治理,取得良好的降噪效果。２　噪声机理分析　　球磨机是工业生产中粉碎物料的一种常见的机械设备,球磨机的噪声,是由于钢球与筒体之间撞击,以及物料间的相互摩擦产生的。用精密声级计测量,设备噪声达１０８ｄＢ（Ａ）,用频谱分析仪测量数据如下,并绘出频谱图。频率（Ｈｚ）６３１２５２５０５００…     

发电厂球磨机房的噪声控制

本文以山东省石化厅张店热电厂六台钢球磨煤机的噪声治理为例,采用了组装式双层活动轻板和固定式多层复合轻板相结合的隔声房、电动机集风、机房进排风消声系统等综合整治措施,使球磨机房操作区的噪声级平均值从107dB(A)降低至85dB(A).因降噪效果显著、操作维护方便、环境洁净美观,用户十分满意.该项目的技术措施不仅适用放电厂,也可广泛应用於其它工业同类球磨机房中.     

我国隔声材料的进展

隔声是噪声控制工程降低噪声的基本方法之一,隔声材料(或结构)是隔声降噪的物质保证.为了获得一个安静的环境,一方面是不让外界噪声传入;另一方面是不让强噪声源向外辐射,因此需要采用隔声结构如隔墙,隔声间或隔声罩等进行隔声,以减小噪声对环境的干扰.墙体是一种量大面广的隔声结构,而粘土砖则是传统的主要墙体材料.由于实心砖墙的厚度大、面密度重,根据隔声质量定律砖墙具有良好的隔声性能.通常所称的1砖墙(不包     

机场附近的噪声环境和住宅的隔声改造

对首都机场的飞机机型和机场附近住宅的噪声现状进行监测,采用计权等效连续感觉噪声级和昼夜等效声级对室外的飞机噪声进行综合评估,提出关于机场周围建筑物隔声标准和方法的建议。以首都机场周边某住宅为例进行隔声治理,飞机起飞经过13 s时室内外开关窗的噪声值和室内现场隔声量的测量结果表明,居民对房屋隔声效果反应良好,隔声后改善了居民住宅内的声环境质量。     

钻柱信道内隔声体结构建模与仿真分析

在随钻声传输技术中自钻柱底部上行的井下噪声及回波干扰严重降低声信号接收性能。基于低频纵波在声阻抗突变处及周期性管结构信道内的传输特性,设计具有周期性凹槽的隔声体结构。结合信道内噪声特征及隔声阻带中心频率,比较分析单结构隔声体短节与组合结构隔声体频响特性及隔声量,并将隔声体引入钻柱信道,用钻柱内一维低频纵波传输有限差分算法,时、频域仿真分析隔声体在信道内的隔声性能。结果表明,组合隔声结构可实现较宽的隔声频带,使噪声水平降低20~40 dB,从而改善信噪比、提高传输速率,为钻柱声遥测系统优化设计提供方法基础。     

隔声墙在电厂干煤棚的应用

利用隔声技术可以治理噪声,文中阐述提高隔声墙隔声能力的措施。针对位于城区的电厂干煤棚的噪声严重影响了周围居民的生活,灵活应用提高隔声墙隔声能力的措施,采用具有吸声能力的多层复合结构隔声墙对干煤棚的噪声进行治理,得到了很好的效果。文中用实际的工程例子探讨隔声技术的实际应用问题,可为相关隔声工程提供参考。     

A计权隔声量与频带隔声降噪量

隔声,在工业噪声控制中,是一种常用的噪声治理措施.隔声效果的评价,可用对声源采取隔声措施前后,车间内作业场所同一点的噪声值下降量来表示,即插入损失.因用仪器A挡读数,故称A计权隔声量.用A计权隔声量来评价隔声装置的效果,在实际使用中是很方便的.如某作业场所的噪声值为110分贝(A),对声源进行隔声措施后,在同一点测出噪声值为85分贝(A),得出该隔声装置的A计权隔声量为25贝,这能很直观地看出隔声效果,且治理后的噪声值与工业企业噪声卫生标准规定的值都用A声级表示,具有一致性.隔声设计时,声源的噪声值包括A声级和频带声压级可通过测量得到.根据声源噪声值的大小,对照工业企业噪声卫生标准的规定值,可确定设计要求的A计权隔声量的值.但A计权隔声量不能直接选用隔声构件     

建筑围护结构在隔声中的应用(修改稿)

本文研究的目的是将现有的常用建筑围护结构有针对性地应用于煤矿风井噪声控制工程中,达到隔声目标,降低工程造价,消除矿区环境噪声污染。通过对不同建筑围护结构隔声性能的分析与比较研究,论证其对不同频谱特性噪声源的隔声可行性。轻型或重型的建筑围护结构透声系数较小,具有一定的隔声作用,根据不同围护结构的隔声性能,结合噪声源的频谱特性,通过隔声间、隔声罩、声屏障或其他形式组合隔声方式,有针对性地阻断噪声的传播。技术应用于煤矿风井的电机、风机及出风口噪声控制工程中,可操作性强,降噪效果明显,对类似噪声控制工程有较强的指导作用。     

用隔声套法治理大型球磨机噪声的设计

通过紧箍于大型球磨机筒体的多层复合材料的隔音、吸声和阻尼作用，能使球磨机噪音降低１５－２０ｄＢ（Ａ）这种阻尼隔声套操作维修也较方便。     

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.