压力机噪声、振动公害源分析及防治

<正> 压力机是工业企业中常用的冲压设备之一,是一种产生公害的设备,尤其是汽车、拖拉机行业的产品中冲压件所占的比例很大,例如,汽车产品的冲压件约占70％左右,所以这种企业使用的压力机台数较多,对厂内职工及附近居民的危害也比较大,因而对压力机产生的噪声、振动进行防治具有     

模锻设备的选型与比较

通过对目前锻造行业的四大主力模锻设备：蒸空模锻锤、螺旋压力机、热模锻压力机、程控锻锤等各自结构性能特点的比较及选型介绍,阐述了4种模锻设备各自不同的适应性,阐明模锻设备的选型应针对锻件的形状、精度及工艺特点合理确定。     

低碳钢的落料(6)

12 运用条件为了提高生产率和降低单件成本,大多数落料是通过高速机械压力机完成的。每分钟冲程数高达1200次的压力机常被采用。高速落料设备一般包括短冲程压力机,自动送料装置及设计成有底部也料功能的冲模。在大多数落料工序中,压力机速度受进料长度的所限,进料长度又取决于坯件规格、或取决于压力机功率与载荷之间的关系。复合模中落料     

汽车悬挂横梁的热压成形

我厂生产的产品以冲焊结构为多,冲压件的品种,数量在产品总的零部件中占有很大的比例。无论在军品和民品中,都有许多由中厚钢板制造的冲压件,厚度由5mm 到4Dmm 不等,材料既有普通和优质炭素钢 A3,4D,也有低合金结构钢30CrMnSi,09Mn-Rel 等。为保证产品质量,防止开裂,以及从模具强度和设备负荷几方面考虑,对中厚钢板冲压件往往采用热压成形。现以铁马牌载重汽车的悬挂横梁为例,介绍中厚钢板热压成形的工艺制定,模具设计及操作中应注意的几个问题。     

摩擦压力机打击力的测量误差分析

对摩擦压力机打击力测量不准确的现象进行了试验验证 ,并从理论上分析了摩擦压力机打击力测量误差产生的原因 ,探讨了摩擦压力机滑块初速度、工件质量和刚度以及测力传感器质量和刚度对摩擦压力机打击力测量误差的影响。     

鸡西市恒山区污水处理厂加药设备改造研究

针对鸡西市恒山区污水处理厂改造,研究了增加污水处理厂加药设备方案,同时对污水处理厂加药设备的结构设计和优化进行了探讨。根据污水处理设备的技术性能和污水处理设备的标准,进行了污水处理设备工艺优化、探讨了成套溶药投药系统组成及性能,确定了全套溶药投药系统的规格和投药设备运行条件;研究了保证装置焊缝质量,确保加药装置密封性措施;最后提出设备预组装方案与设备运转试车方案,为鸡西市恒山区污水处理设备改造成功奠定了基础。     

曲柄压力机的允许负荷曲线

曲柄压力机的允许负荷曲线是压力机的主要技术文件,是合理地选用压力机的依据。文章中除对通常使用的“允许负荷—滑块行程”允许负荷曲线外,还对“允许偏心负荷—负荷偏心距”“允许集中负荷—负荷分布长度”等另外两类允许负荷曲线作了分析,给出了计算公式。并针对开式压力机及闭式双点压力机,作出了三类允许负荷的图表及曲线,为了使用方便,曲线的横座标不用曲柄转角而是改用滑块行程。文章最后给出了应用举例。可供从事冲压技术工作人员参考使用。     

减少金属材料消耗的锥形薄壁冲压件

通过使冲压件等强度提高的方法可以降低深锥形轴对称薄壁冲压件(如高压容器、转换器接头、飞机头整流罩等等)的金属消耗。深锥形轴对称薄壁冲压件的等强度提高是由拉深与缩口工序相结合进行冲压时得到     

旧油船上可再利用设备的评估方法

在旧油船改造FPSO项目的投标阶段,为了设计有市场竞争力的设备改造方案,建立了旧油船上可再利用设备的状态评估方法。此设备状态评估方法是在研究国外油船改造FPSO工程案例基础上,先分析出油船上可再利用设备的清单,再基于船级社的规范和FPSO的设计功能需求,确定了油船上设备的检查与测试项目及各项目的权重占比,最后对油船上可再利用设备的状态进行定量评估,从而确定经济效益最佳的油船上设备的改造方案。     

大柳塔生活污水处理一期生物转盘改造方案探讨

大柳塔生活污水处理厂一期工程采用生物转盘处理生活污水,因设备故障频繁停用,现根据二期工程接触氧化法的运行情况,欲对其进行改造,本文就其改造方案及技术经济指标进行了探讨。     

Promoting factors and early indicators of a successful product panel

Product panels are presented as a promising method to find solutions for environmental problems arising from specific product groups. These panels consist of representatives of manufacturers, retail, research, environmental and consumer administration, recycling, and various other stakeholders who work together in the panel to draft plans of action aiming at improvements in the environmental characteristics of products and services, and promotion for environmentally sound products and services in the various markets.The purpose of this paper is to examine the factors that promote successful panel work as based on the experiences from the Danish and Finnish product panels. In addition, we aim at finding several indicators in panel work that can help lead to successful results already in the early phase and, on the other hand, help to recognize panels that will be ineffective from the viewpoint of environmental policy. We also describe how the findings from the Danish and Finnish textile panels were applied to a new product panel in Finland dealing with furniture and how this panel has started its work.The paper is based on existing material about the three panels, including reports and websites of the Danish product panels and the Finnish Furniture panel. In addition, unpublished memos of the meetings of the three panels have been studied. An evaluation report of the Danish panels was very useful for the discussion of the findings. The authors have also participated in the furniture panel as a member and a secretary.Experiences from the Danish textile panel and some early results of the Finnish furniture panel indicate that, under the right conditions, gathering stakeholders from the whole product chain and administration into a panel can be an efficient way to promote the market for greener products and thus, can serve as a tool for integrated product policy. Key success factors include the basic idea, committed people and openness of the product panels. It is also important that the initiator give some guidance in the form of schedule, action plan and some preset objectives.     

An overview of reproductive carrier screening panels for autosomal recessive and/or X-linked conditions: How much do we know?

Background & Aim

Reproductive carrier screening seeks to identify couples at a high risk of having offspring affected by autosomal recessive and X-linked (XL) conditions. The aim of this paper is to provide a comprehensive overview of existing carrier screening panels by examining their gene content and characteristics, identifying the most common genes/conditions included in these panels, and analyzing their listed prices.

Methods

A comprehensive evaluation of existing carrier screening panels was conducted by searching for web-based content, reviewing information brochures, and establishing direct contact with the providers via email or phone.

Results

Twenty-two panels and their providers were identified with a cumulative total of 2205 unique genes. The number of genes included in these panels varied from 44 to 2054. Only 15 genes (0.7%) were included in all the panels. The carrier frequency of these 15 common genes and their associated conditions varied greatly, but the conditions associated with the genes are “severe”. The price of these 22 panels ranged from $349 to $4320 per couple (USD in 2023). The correlation between the listed price and the number of selected genes among these panels was small and not statistically significant (r = 0.1023, p = 0.6959).

Conclusion

Considerable discrepancies exist among carrier screening panels. Ongoing research and monitoring are necessary to capture the dynamic nature of the carrier screening landscape, providing up-to-date information for clinical practice and informed decision-making.     

多层阻尼复合板常温贮存5年性能研究

目的分析多层阻尼复合板常温贮存5年的性能变化。方法对多层阻尼复合板进行常温下贮存5年的减振性能研究,通过贮存前后的正弦扫描试验和随机振动试验,获得贮存前后多层阻尼复合板的减振性能和模态变化,进行对比分析。结果阻尼复合板常温贮存5年后,径向模态有较大的下降,法向模态变化较少,组件上的加速度响应基本无变化。结论该多层阻尼复合板常温贮存5年后仍然满足要求。     

室内环境对人造板甲醛释放规律影响分析研究

为了研究不同温湿度条件下人造板甲醛的释放规律,利用环境舱模拟人造板在室内特征温湿度下甲醛的散发过程,测量甲醛的逐时散发浓度。结果表明,温度升高,木板中甲醛的释放浓度增大,环境舱内木板甲醛释放达到稳定的时间越长;相对湿度增加,木板中甲醛释放浓度随之增加。改变温湿度对环境舱内板材甲醛的释放趋势影响小。夏季工况的温湿度均高于冬季和过渡季,所以甲醛释放浓度为夏季＞过渡季＞冬季,其峰值浓度高于其他两季约3～5倍。     

废手机面板焚烧产物研究

以废手机面板为试验材料,利用热重分析仪(TGA)研究热处理失重特征,同时利用气相色谱仪-质谱仪联用(GC-MS)对管式炉试验系统焚烧产物进行分析. 结果表明:废手机面板焚烧失重温度为128.3～558.1 ℃,最大失重温度为357.4 ℃;焚烧废手机面板导致面板组成材料液晶、偏光片和取向剂等发生化学反应,焚烧产物除CO₂外,还含有醛、酮、联苯酚、苯胺等芳香族化合物和少量的苯并吡喃、萘、菲、吡啶等多环芳烃(PAHs). 由于焚烧产物中绝大多数是有毒有害物质,部分可致癌,故废手机面板不宜焚烧处理,如与其他固体废物混合焚烧,必须采取相应的污染控制措施.      

板材甲醛释放实验及其释放参数的测定

采用1m3的小型环境模拟舱,测试了不同温度和装载度条件下胶合板、密度板、细木工板和复合地板中甲醛释放规律.研究发现:甲醛浓度在初始阶段(0~3h)均迅速增大,随后速度慢慢减小,最后浓度趋于恒定值;温度升高会促进板材内甲醛释放,温度每升高5 ℃,甲醛释放量会增加10%~30%;而装载度增大则会减少单位体积板材内甲醛的释放量.利用不同装载度条件下板材在密闭环境舱散发过程和平衡状态浓度,求解了影响板材释放特性的关键释放参数:可散发初始浓度Cm,0、扩散系数Dm和分配系数K;模拟计算的浓度结果与实验测试数据吻合良好,为研究板材甲醛释放规律提供了一种有效手段.     

家具板材排放VOCs成分谱及排放因子研究

随着目前人们对室内空气质量要求的不断提高,家具板材作为影响室内空气质量的VOCs（挥发性有机物）排放源,也逐渐受到重视.采用500 L静态箱,使用PTR-TOF-MS（质子转移反应-飞行时间质谱）对市售六类家具板材排放的VOCs进行测定,分别进行排放速率与排放平衡试验得到板材的排放特征与排放成分谱,并估算其排放因子.结果表明:①集成材、胶合板、细木工板、刨花板、密度板、实木地板8 h排放的ρ（TVOC）（TVOC为总挥发性有机物,total volatile organic compound）平均值分别为0.76、0.39、0.42、0.68、0.17、0.23 mg/m3,各类板材主要排放物种分别为甲苯、甲醛、甲醛、正壬烷、甲醇、甲醛,其质量浓度平均值分别为0.23、0.23、0.13、0.35、0.04、0.06 mg/m3.②排放平衡试验中焕城胶合板、吉林松木集成材、凯越密度板及时代刨花板TVOC的排放因子分别为3.63、10.63、0.51、2.07 g/m3.③板材排放VOCs成分谱中,焕城胶合板主要排放物种为丙烷、乙烷、甲醛、甲醇,其排放占比分别为18.57%、4.73%、19.74%、17.83%;吉林松木集成材主要排放物种为甲苯,其排放占比为43.27%;凯越密度板主要排放物种为乙烷与甲醛,其排放占比分别为26.44%、19.42%;时代刨花板主要排放物种为甲醛与甲醇,其排放占比分别为40.16%、31.55%.研究显示,各类板材VOCs排放特征、排放成分谱及排放因子均存在较大差异,部分板材VOCs排放量较大,需加强行业标准的规范化.      

Single-stroke mechanical joining of sheet panels to tubular profiles

This paper proposes an innovative mechanical joining process for fixing sheet panels against tubular profiles with a single ram stroke.The presentation includes independent determination of the mechanical properties of sheets and tubes, finite element modelling and experimentation under laboratory conditions. The aim is to identify the key parameters of the process, to diagnose possible sources of failure and to understand the routes for selecting the most appropriate joining conditions.Results and observations show that fixing sheet panels to tubular profiles by tube forming with a single ram stroke is a flexible and cost-effective mechanical joining process that can be easily industrialized in a small capacity press. Applications may span for a wide range of engineering applications where conventional technologies based on fasteners, glueing with structural adhesives, brazing and soldering or welding cannot be employed due to technical, aesthetical or economic constraints.     

Joining sheet panels to thin-walled tubular profiles by tube end forming

This paper is focused on novel utilizations of the fundamental modes of deformation of tube end forming for assembling sheet panels to thin-walled tubular profiles.The objective is to present an innovative and environmental friendly joining technology built upon the combination of compression beading with tube inversion that can successfully eliminate currently available technologies based on mechanical fixing with fasteners, welding and structural adhesive bonding. The technology works at room temperature, is capable of ensuring significant economic and time savings and offers potential for opening new markets for the assembly of lightweight frame structures.The presentation is supported by experimentation and numerical modelling based on independently determined mechanical properties of the materials with the purpose of characterizing and evaluating the process feasibility limits as a function of the major operative parameters.The feasibility of joining sheet panels to tubular profiles by means of the proposed technology is demonstrated by presenting industrial applications and by evaluating the performance of a safety auto part in an operation failure test.     

恶臭嗅辨实验室的建立与发展研究

在使用国家推荐标准方法《空气质量恶臭的测定三点比较式臭袋法》（GB／T14675—93）测定恶臭气体浓度时,环节较多较繁杂,需要人工配气和人工嗅辨,监测过程中使用的器材、设备较多,因此容易引入误差。笔者建议从器材设备、实验室布局、嗅辨员选择等方面加强质量管理,通过严格执行相关标准,规范配气和嗅辨环节,加强质量控制等措施建立标准、规范的实验室,以提高监测结果的准确性。文章也简要介绍了国内外针对该方法监测过程中人工配气、人工嗅辨、人工计算的三大环节所开展的探索。