Occupational exposure and health risks of volatile organic compounds of hotel housekeepers: Field measurements of exposure and health risks

Hotel housekeepers represent a large, low-income, predominantly minority, and high-risk workforce. Little is known about their exposure to chemicals, including volatile organic compounds (VOCs). This study evaluates VOC exposures of housekeepers, sources and factors affecting VOC levels, and provides preliminary estimates of VOC-related health risks. We utilized indoor and personal sampling at two hotels, assessed ventilation, and characterized the VOC composition of cleaning agents. Personal sampling of hotel staff showed a total target VOC concentration of 57 ± 36 µg/m³ (mean ± SD), about twice that of indoor samples. VOCs of greatest health significance included chloroform and formaldehyde. Several workers had exposure to alkanes that could cause non-cancer effects. VOC levels were negatively correlated with estimated air change rates. The composition and concentrations of the tested products and air samples helped identify possible emission sources, which included building sources (for formaldehyde), disinfection by-products in the laundry room, and cleaning products. VOC levels and the derived health risks in this study were at the lower range found in the US buildings. The excess lifetime cancer risk (average of 4.1 × 10⁻⁵) still indicates a need to lower exposure by reducing or removing toxic constituents, especially formaldehyde, or by increasing ventilation rates.     

于都县黄麟地区绿色富硒土壤分布选区评价

通过于都县黄麟地区1:5万土地质量地球化学调查,基本査明该地区农作物中硒元素及其他元素的地球化学特征,综合分析岀绿色富硒土壤分布,并优选出绿色富硒地块,为特色农产品基地建设的开发与利用提供理论依据。     

四川盆地高石梯-磨溪地区下二叠统气源示踪

以天然气、烃源岩及储层沥青的地球化学特征为主要依据,通过天然气-天然气、储层沥青-烃源岩、天然气-烃源岩3个方面对比,深入探讨四川盆地高石梯-磨溪地区下二叠统天然气来源。研究表明,四川盆地高石梯-磨溪地区下二叠统天然气主要来源于筇竹寺组泥岩。其5项证据分别为:下二叠统天然气乙烷碳同位素小于-30.5‰,甲、乙烷碳同位素倒转是由高演化程度烃源岩所致;多数下二叠统天然气与龙王庙组天然气特征最为相似;GS18,NC1井下二叠统天然气特征与寒武系相似,说明上下层气源一致;高石梯-磨溪地区下二叠统储层沥青地球化学特征与筇竹寺组泥岩最为相似;筇竹寺组泥岩主要为下二叠统供气,这一认识符合干酪根油气生成理论和同位素分馏规律。     

CO2 sequestration by magnesite mineralisation through interaction of Mg-brine and CO2: integrated laboratory experiments and computerised geochemical modelling

ABSTRACT

Several Carbon Capture and Storage (CCS) techniques have been studied including injections of carbon dioxide (CO₂) into the mature and/or depleted hydrocarbon reservoirs and deep saline aquifers. This work aims to test storing CO₂ into the magnesium-rich evaporite strata and also into the stratigraphic intervals containing Mg-rich brines. The test simulates Mg-carbonation of the synthetic solution obtained from the Mg-evaporite mineral, bischofite – both experimentally in the laboratory condition and also through computerised geochemical simulation. The laboratory experiments, which resulted in the crystallisation of anhydrous magnesite, were analysed. The TOUGHREACT^TM, Geochemist’s Workbench^TM (GWB) and PHREEQC^TM software simulated the experiments as computerised geochemical model and tested the results for natural geological conditions. The geochemical simulations successfully demonstrate the immense CCS potential for the Mg-evaporite (as well as the sedimentary strata charged with Mg-evaporitic brine) at their subsurface geological occurrences at elevated pressure-temperature and high salinity.     

云南省澜沧老厂—孟连茶场地区成矿规律及找矿方向探讨

澜沧老厂—孟连茶场地区位于昌宁—孟连多金属成矿带，研究区域成矿规律对找矿突破有着重要指导意义。在综合分析研究地质背景、化探异常、矿产分布等特征的基础上，将该地区划分为老厂、拉巴、孟连矿（化）集区。老厂铅锌矿床是区域上的典型矿床，其在化探异常、矿床空间分布具有明显的低中高温成矿分带的特征。以该矿床分带特征入手，指出老厂矿（化）集区在地表以低温成矿元素为主，而拉巴、孟连矿（化）集区在化探异常、矿化特征均以低中温成矿元素为主，空间上分带特征不明显。该地区化探异常、矿（化）体分布特征，均表明区域上成矿温度、成矿标高由北至南均具从高到低的降低趋势，认为其可能与燕山期岩浆活动的差异性有关，指出老厂外围、拉巴深部是找矿的有利靶区。     

Failure load prediction and optimisation for adhesively bonded joints enabled by deep learning and fruit fly optimisation

Adhesively bonded joints have been extensively employed in the aeronautical and automotive industries to join thin-layer materials for developing lightweight components. To strengthen the structural integrity of joints, it is critical to estimate and improve joint failure loads effectually. To accomplish the aforementioned purpose, this paper presents a novel deep neural network (DNN) model-enabled approach, and a single lap joint (SLJ) design is used to support research development and validation. The approach is innovative in the following aspects: (i) the DNN model is reinforced with a transfer learning (TL) mechanism to realise an adaptive prediction on a new SLJ design, and the requirement to re-create new training samples and re-train the DNN model from scratch for the design can be alleviated; (ii) a fruit fly optimisation (FFO) algorithm featured with the parallel computing capability is incorporated into the approach to efficiently optimise joint parameters based on joint failure load predictions. Case studies were developed to validate the effectiveness of the approach. Experimental results demonstrate that, with this approach, the number of datasets and the computational time required to re-train the DNN model for a new SLJ design were significantly reduced by 92.00% and 99.57% respectively, and the joint failure load was substantially increased by 9.96%.     

一种精确测量ASTM标准圆形拉伸试样锥度的方法

介绍了ASTM标准中圆形拉伸试样主要部位的尺寸与要求。采用国产万能工具显微镜-投影法对试样在平行长度部位的锥度进行了测量。该方法简便易行,结果准确可靠,满足了标准要求,同时发挥了老设备的作用,保证了试样的加工精度。     

分析化验技术及标准在天然气处理厂中的应用

简要介绍了天然气的分类,及天然气处理过程中相关气体、液体及固体样品的分析测试方法和标准。论述了相关分析化验技术及标准在国内、外有代表性的两个大型天然气处理厂新疆大北项目和土库曼斯坦南约洛坦项目中的应用。     

关于油砂地球化学研究方法

随着对能源需求增加和技术的进步,油砂资源受到世界各国重视。油砂是烃源岩中的原油在构造运动等作用的影响下,经一次或多次运移后,储层遭受一系列次生蚀变作用,造成其中极性重质组分富集而形成。研究油砂地球化学特征可以确定其是否具有工业开采价值,以及其烃源岩的沉积环境、有机质类型、热演化程度、有机质成熟度等。通过不同油砂的地化指标对比,可以知道它们的原油的运移方向,指导油气和油砂的勘探。     

电感耦合发射光谱测煤灰中的元素

本文用三标准试样法来做校正曲线,用电感耦合离子发射光谱来测煤灰中Si、Al、Fe、Ca、Mg、Ti、S、P,这种方法方便快捷,准确度高,能同时测多种元素,每种元素的线性相关系数都大于0.999。