Quantification and source characterization of volatile organic compounds from exercising and application of chlorine-based cleaning products in a university athletic center

Humans spend approximately 90% of their time indoors, impacting their own air quality through occupancy and activities. Human VOC emissions indoors from exercise are still relatively uncertain, and questions remain about emissions from chlorine-based cleaners. To investigate these and other issues, the ATHLETic center study of Indoor Chemistry (ATHLETIC) campaign was conducted in the weight room of the Dal Ward Athletic Center at the University of Colorado Boulder. Using a Vocus Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOF), an Aerodyne Gas Chromatograph (GC), an Iodide-Chemical Ionization Time-of-Flight Mass Spectrometer (I-CIMS), and Picarro cavity ringdown spectrometers, we alternated measurements between the weight room and supply air, allowing for determination of VOC, NH₃, H₂O, and CO₂ emission rates per person (emission factors). Human-derived emission factors were higher than previous studies of measuring indoor air quality in rooms with individuals at rest and correlated with increased CO₂ emission factors. Emission factors from personal care products (PCPs) were consistent with previous studies and typically decreased throughout the day. In addition, N-chloraldimines were observed in the gas phase after the exercise equipment was cleaned with a dichlor solution. The chloraldimines likely originated from reactions of free amino acids with HOCl on gym surfaces.     

明确方向 促进发展——旅游村镇建设指导与评价研讨会探讨旅游村镇建设工作

2006年6月26日至30日,建设部村镇建设办公室和国家旅游局政策法规司联合在北京召开了旅游村镇建设指导与评价研讨会。来自中国建筑设计研究院小城镇发展研究中心、浙江省旅游标准化技术委员会等单位的十余位专家齐聚一堂,共同研究旅游型村镇建设工作。会议期间召开了多次专家座谈会,结合全国旅游小城镇发展工作会议精神,在此前完成的两份标准草案的基础上整合形成了《中国旅游·建设名镇(村)评定标准》以及《中国旅游·建设名镇(村)评选办法》初稿。在会议期间,专家们畅所欲言,就发展旅游型村镇的意义、形势、任务,目前存在的问题和今后的发…     

科学制定标准促进旅游型村镇健康发展——《中国旅游·建设名镇(村)评定标准》(暂定名)编制中的一些思考

建设部村镇建设办公室委托中国建筑设计研究院小城镇发展研究中心负责组织编写《中国旅游·建设名镇(村)评定标准》(以下简称《标准》)建设部分的评定内容。编写组根据建设部和国家旅游局领导关于发展旅游小城镇所达成的共识和要求,以及自身对此项工作的认识,就编写《标准》谈一些体会,与读者共享。一、开展中国旅游·建设名镇(村)评定工作的背景近几年,中央加大了对“三农”工作的政策支持力度。2004年,中央提出了“两个趋向”的重要论断,并指出我国已经进入“以工促农、以城带乡”的重要阶段;2005年,党的十六届五中全会上提出了建设社会主…     

Homeowner investor subjects as providers of family care and assistance

Abstract

This article asks: What becomes of the idealized asset-accumulating investor subject rallied in asset-based welfare policy and discourse in the context of mounting social risks facing families? It brings into dialogue two disconnected literatures: one on financialized subjectivities, drawing on post-structuralist and Foucauldian analysis, the other on welfare states drawing more heavily on comparative political economy. Drawing on homeowner interviews in Melbourne (Australia), it identifies how parent homeowners’ devise housing strategies to manage their children’s housing welfare risks. Their housing investment and landlordism strategies align with financialized subjectivities, but other strategies subvert or reject these subject positions. Its first contribution is to specify how an Australian refamilization of welfare responsibilities, including for housing, is unfolding as processes of financialization erode the efficacy of growing state social spending. Its second contribution is to challenge the individual subject of asset-based welfare (ABW) and introduce intergenerational assistance as an under-explored contingency for ABW projects, and further driver for welfare inequalities between and within generations.     

Avalanches on a conical bead pile: scaling with tuning parameters

Uniform spherical beads were used to explore the scaling behavior of a granular system near its critical angle of repose on a conical 3D bead pile. We found two tuning parameters that could take the system to a critical point. The existence of those tuning parameters violates the fundamental assumption of self-organized criticality, which proposed that complex dynamical systems self-organize to a critical point without need for tuning. Our avalanche size distributions were well described by a simple power-law, as is characteristic of a critical point, with the power τ = 1.5 when dropping beads slowly onto the apex of a bead pile from a small height. However, we could also move the system from the critical point using either of two tuning parameters: the height from which the beads fell onto the top of the pile or the region over which the beads struck the pile. As the drop height increased, the system did not reach the critical point yet the resulting distributions were independent of the bead mass, coefficient of friction, or coefficient of restitution. All our apex-dropping distributions for any type of bead (glass, stainless steel, zirconium) showed universality by scaling onto a common curve with τ = 1.5 and σ =?1.0, where 1/σ is the power of the tuning parameter. From independent calculations using the moments of the distribution, we find values for τ = 1.6 ± 0.1 and σ =?0.91 ± 0.15. When beads were dropped across the surface of the pile instead of solely on the apex, then the system also moved from the critical point and again the avalanche size distributions fell on a common curve when scaled similarly using the same values of τ and σ. We also observed that an hcp structure on the base of the pile caused an emergent structure in the pile that had six faces with some fcc or hcp structure; this structure did not affect the distribution of avalanche sizes.     

High-throughput nuclear magnetic resonance analysis using a multiple coil flow probe

An automated method for high-throughput nuclear magnetic resonance (NMR) spectroscopy has been developed using a four-coil Multiplex NMR probe. The probe is constructed with solenoidal microcoils optimized for detection of small volume, mass-limited samples and a flow-through design. Four samples can be simultaneously injected into the Multiplex probe with a robotics liquid handler and then analyzed in rapid succession using a selective excitation experiment. Due to the simultaneous injection of four samples and the reduced analysis time with rapid selective excitation, the analysis rate achieved thus far is as low as 1 sample/34 s for 1D 1H NMR.     

Stabilization of Sn Anode through Structural Reconstruction of a Cu–Sn Intermetallic Coating Layer

The metallic tin (Sn) anode is a promising candidate for next-generation lithium-ion batteries (LIBs) due to its high theoretical capacity and electrical conductivity. However, Sn suffers from severe mechanical degradation caused by large volume changes during lithiation/delithiation, which leads to a rapid capacity decay for LIBs application. Herein, a Cu–Sn (e.g., Cu₃Sn) intermetallic coating layer (ICL) is rationally designed to stabilize Sn through a structural reconstruction mechanism. The low activity of the Cu–Sn ICL against lithiation/delithiation enables the gradual separation of the metallic Cu phase from the Cu–Sn ICL, which provides a regulatable and appropriate distribution of Cu to buffer volume change of Sn anode. Concurrently, the homogeneous distribution of the separated Sn together with Cu promotes uniform lithiation/delithiation, mitigating the internal stress. In addition, the residual rigid Cu–Sn intermetallic shows terrific mechanical integrity that resists the plastic deformation during the lithiation/delithiation. As a result, the Sn anode enhanced by the Cu–Sn ICL shows a significant improvement in cycling stability with a dramatically reduced capacity decay rate of 0.03% per cycle for 1000 cycles. The structural reconstruction mechanism in this work shines a light on new materials and structural design that can stabilize high-performance and high-volume-change electrodes for rechargeable batteries and beyond.     

Coating effects on mid-infrared reflection spectra of fabrics

Polymer films of varying thicknesses were deposited onto cotton and polyester fabric samples by dip-coating from solution. Scanning electron microscopy (SEM) images of the coated fabric samples were used to evaluate the quality of the polymer coating. The samples were analyzed by infrared diffuse reflection spectroscopy to determine the relationship between film thickness and the effect of the coating on the spectroscopy of the two fabrics. Effects observed in four limiting cases are examined: (Case I) weak coating absorption on a fabric with weak absorption at the same frequency; (Case II) strong coating absorption in a spectral region of weak fabric absorption; (Case III) weak coating absorption in a spectral region of strong fabric absorption; and (Case IV) strong coating absorption in a spectral region of strong fabric absorption. In the first case, effects were dominated by reduced scattering as the coating is added. In the second case, the strong coating absorption that was observed at low coverages plateaus at higher coverage due to depth of penetration effects. In the third and fourth cases, reduced Fresnel diffuse reflection is measured as the coating is added, consistent with the reduction of scattering observed in the first case.