PM1切割器的评价及其与PM2.5切割器的切换研究

开展了PM₁切割器的性能评价研究,通过搭建基于静态箱法的评价系统,选用8种粒径的单分散聚苯乙烯微球,结合空气动力学粒径谱仪获取PM₁切割器的捕集效率,最终得出拟合曲线.通过该方法测量得出某台BGI的PM₁切割器在16.67 L·min^-1工作流量下的50%切割粒径分布在(1.0±0.1) μm范围内,几何标准偏差分布在1.2±0.1范围内.同时研究了采样流量对PM₁切割器性能的影响,发现50%切割粒径随流量增大呈现减小趋势,而几何标准偏差一致性较好,偏差不超过1%,尤其当采样流量为6.77 L·min^-1时,PM₁切割器的性能可调整为符合国家标准对PM_2.5切割器的要求,本研究成果为PM₁切割器评价方法及性能指标的确定提供了参考.     

Kickback risk of portable chainsaws while cutting wood of different properties: laboratory tests and deductions

Portable chainsaws are associated with substantial risk and can cause serious injury to operators, especially during kickback. This paper presents new results from research and analyses conducted regarding the impact between the different properties of wood on this occurrence. In an open area, such differences may include: wood species, humidity, temperature and the facing angle of the wood fibres in relation to the kerf and shape of the wood surface that comes in contact with the tip of the guide bar. This paper investigates chainsaw kickback including the research results on kickback and wood-cutting energy, saw chain speed and the efficiency of the chainsaw engine. It also presents conclusions drawn from the tests that can be useful for chainsaw users, showing the dependencies between the different properties of wood and the risk of injury.     

Oracle-based optimization applied to climate model calibration

In this paper, we show how oracle-based optimization can be effectively used for the calibration of an intermediate complexity climate model. In a fully developed example, we estimate the 12 principal parameters of the C-GOLDSTEIN climate model by using an oracle-based optimization tool, Proximal-ACCPM. The oracle is a procedure that finds, for each query point, a value for the goodness-of-fit function and an evaluation of its gradient. The difficulty in the model calibration problem stems from the need to undertake costly calculations for each simulation and also from the fact that the error function used to assess the goodness-of-fit is not convex. The method converges to a ‘best fit’ estimate over 10 times faster than a comparable test using the ensemble Kalman filter. The approach is simple to implement and potentially useful in calibrating computationally demanding models based on temporal integration (simulation), for which functional derivative information is not readily available.     

负载CuO/MnO海泡石中性条件催化H_2O_2处理铝材切削液废水

以改性海泡石为载体,采用浸渍-共沉淀法负载Cu0、MnO制备了中性条件下催化H_2O_2氧化催化剂(简称中性催化剂)。以铝材切削液废水为处理对象,研究了催化剂在中性条件下的催化性能,通过投加不同浓度的羟基自由基捕捉剂叔丁醇,对反应机理进行了探讨,同时研究了过氧化氢用量、催化剂用量等因素对废水COD去除率的影响。结果表明:在中性条件下,催化剂对铝材切削液废水具有较高的COD去除率,当过氧化氢用量为1.25 mol/L,催化剂用量为25 g/L,室温条件反应120 min时,COD去除率达到88%;经该方法处理后,废水ρ(BOD5)/ρ(COD)由处理前的0.09提升到处理后的0.36,可生化性得到了明显提高。     

手工法与自动监测法测定PM2.5质量浓度比对研究

采用小流量颗粒物采样器手工采样重量法和基于微振荡天平原理自动监测法监测PM2.5质量浓度。通过2010年9月至2011年8月期间两种方法的监测数据比对显示出季节差异,冬、春两季手工法获得质量浓度高于自动法,夏、秋两季手工法低于自动法,可能与两种采样方法下膜置于不同的温度有关。当受沙尘影响、持续污染或者高温污染时,两种方法结果偏差较大,可能与仪器的粒径切割效率改变有关。     

Generic scenario for the impact of cooling lubricants into the hydrosphere

According to directive 93/67/EEC of the European Commission, this paper deals with the generic exposition evaluation of the environmental concentration of cooling Lubricant chemicals from the metal working industry into the hydrosphere. After considering the relevant life-cycle steps and the selection of a representative point source for the 'reasonable worst case', the emission per day Elocal(water) is determined. It leads to the predicted environmental concentration (PEClocal(water)) for the local stage in the compartment water. In order to gain the PEClocal(water) for an example--a corrosion inhibitor as additive in a cooling lubricant--, the relevant emission paths and the corresponding representative point source are described for the reasonable worst case. For non-water-miscible cooling lubricants, none of the operations in the life cycle leads to a release into the compartment water. To evaluate the hazard potential for cooling lubricant chemicals, the complete risk assessment has to be done. Also, the assessment has to be done for all high production volume chemicals, new substances and existing hazard chemicals. This means that even industrial categories like chemicals used in the textile industry or biocides and others have to be evaluated.     

PM1切割器性能测试系统的搭建与应用

为对PM_1切割器的性能进行准确评估,本文设计搭建了两套PM_1切割器性能测试系统.结果发现,多分散气溶胶测试系统发生的气溶胶稳定、均匀,符合对数正态分布;单分散气溶胶测试系统发生的气溶胶稳定,单分散性良好.采用上述两套系统对5种PM1旋风切割器进行了性能评价,结果表明,两套系统测试结果基本一致,5种旋风切割器的切割粒径D50均在(1.0±0.1)μm之间,sharp-cut和Stairmand两类结构设计的切割器几何标准偏差σg分别在1.2±0.1和1.4±0.1之间.     

PM2.5旋风切割器的性能测试与模拟

切割器是PM_(2.5)采样器的关键部件,其性能的优劣将直接影响到采样结果的准确性,对其性能进行测试有助于评估PM_(2.5)采样器采样结果的准确性和可比性.因此,本研究选取两种应用广泛的BGI公司和URG公司生产的PM_(2.5)旋风切割器,分别采用多分散气溶胶和单分散气溶胶标定装置对其性能进行了测试.结果表明,两种装置的测试结果基本一致.BGI和URG切割器的切割粒径D50为(2.5±0.2)μm,能够满足环境空气PM_(2.5)采样要求(HJ 93-2013);BGI切割器的捕集效率几何标准偏差δg为1.2±0.1,满足要求;而URG切割器的δg超出规定范围.同时,本研究获得了切割器采样流量Q与D50的关系式,可通过该关系式改变切割器的Q获得所需的D50;为使BGI切割器的D50在规定的范围内,其流量偏差需限定在设计流量(即16.7 L·min-1)的-1.0%~16.7%之间,而URG切割器的流量偏差需限定在设计流量的-1.3%~16.2%之间.其次,获得了切割器流动雷诺数Ref与无量纲切割粒径D50/DC的关系式,利用该关系式可在保持设计流量不变的情况下,通过改变切割器的出口管尺寸,得到所需的D50.最后,获得了切割器Q与压力损失△P的关系式,采用5种模型对两种切割器的无量纲阻力系数KL进行模拟计算,并与测试计算结果进行比较,发现CasalMartinez模型、Coker模型和Demir模型更适用于BGI旋风切割器的△P预测,而ShepherdLapple模型和CasalMartinez模型更适用于URG旋风切割器的△P预测.     

破乳-混凝-光催化氧化法处理废切削液

采用破乳—混凝—光催化氧化法处理废切削液。先用HNO3破乳;然后用聚硫酸铁(PFS)和阳离子聚丙烯酰胺(PAM)复合混凝废切削液,在废切削液pH=7.5、PFS加入量为1500mg/L、PAM加入量为8mg/L的条件下,混凝效果较好;在混凝后上层清液pH=3、H2O2加入量为60mg/L、FeSO4.7H2O加入量为700mg/L、H2O2分4次加入、紫外光照射6.5h的条件下,COD去除率达98.91%。     

螺纹自动退刀安全防撞装置

高速车削螺纹退刀时，若退刀不及时，极易发生事故。设计了一种装置——螺纹自动退刀安全防撞装置，从而解决了高速车削螺纹退刀困难等一系列问题。