Joint Effects of Multipollutant Mixtures on Mortality in Chengdu,China

Significant epidemiological research has revealed that exposure to air pollution is substantially associated with numerous detrimental health consequences^([1-3]).The negative health effects of individual air pollutants(e.g.,fine particulate matter:PM_(2.5);nitrogen dioxide:NO_(2);carbon monoxide,CO;or ozone:O_(3))have been widely explored^([4]).However,humans are constantly exposed to multipollutant mixtures in real life,and biological responses to inhaled pollutants are likely to depend on the interplay of pollutant mixtures.Therefore,it is critical and imperative to explore the joint effects of multipollutant mixtures on human beings.

Optimal preparation of Bose and Fermi atomic gas mixtures of ^(87)Rb and ^(40)K in a crossed optical dipole trap

We report on the optimal production of the Bose and Fermi mixtures with ^(87) Rb and ^(40)K in a crossed optical dipole trap(ODT).We measure the atomic number and lifetime of the mixtures in combination of the spin state |F=9/2,m_F=9/2) of^(40)K and |1,1>of ^(87) Rb in the ODT,which is larger and longer compared with the combination of the spin state 19/2,9/2) of^(40)K and 12,2) of ^(87)Rb in the ODT.We observe the atomic numbers of ^(87)Rb and ^(40)K shown in each stage of the sympathetic cooling process while gradually reducing the depth of the optical trap.By optimizing the relative loading time of atomic mixtures in the MOT,we obtain the large atomic number of ^(40)K(~6 ×10^(6)) or the mixtures of atoms with an equal number(~1.6 × 10^(6)) at the end of evaporative cooling in the ODT.We experimentally investigate the evaporative cooling in an enlarged volume of the ODT via adding a third laser beam to the crossed ODT and found that more atoms(8 × 10^(6)) and higher degeneracy(T/T_(F)=0.25) of Fermi gases are obtained.The ultracold atomic gas mixtures pave the way to explore phenomena such as few-body collisions and the Bose-Fermi Hubbard model,as well as for creating ground-state molecules of ^(87)Rb^(40)K.

Long-term performance of recycled asphalt mixtures containing high RAP and RAS

The application of reclaimed asphalt pavement(RAP)and reclaimed asphalt shingles(RAS)on asphalt pavement can reduce the asphalt paving cost,conserve energy and protect the environment.However,the use of high contents of RAP and RAS in asphalt pavement may lead to durability issues,especially the fatigue cracking and thermal cracking.It is necessary to conduct a series of analyses on asphalt mixtures containing high RAP and RAS,and seek methods to enhance their long-term performance.This paper provides a comprehensive over-view of the long-term performance of recycled asphalt mixtures containing high contents of RAP and RAS.The findings in this research show that rutting resistance of high recycled asphalt mixtures is not a concern,whereas their resistance to fatigue and thermal cracking is not conclusive.Recycling agents can be used to improve the thermal cracking resistance of high recycled asphalt mixtures.An optimum decision on recycling agents will improve the durability properties of high recycled asphalt mixtures.It is recommended that to use a balanced mixture design approach with testing of the blended asphalt binders will provide better understanding of long-term performance of recycled asphalt mixtures containing high RAP and RAS.

Undrained vane shear strength of sand-foam mixtures subjected to different shear rates

The shear strength of sand-foam mixtures plays a crucial role in ensuring successful earth pressure balance(EPB)shield tunneling.Since the sand-foam mixtures are constantly sheared by the cutterhead and the screw conveyor with varied rotation speeds during tunneling,it is non-trivial to investigate the effect of shear rates on the undrained shear strength of sand-foam mixtures under chamber pressures to extend the understanding on the tunneling process.This study conducted a series of pressurized vane shear tests to investigate the role of shear rates on the peak and residual strengths of sand-foam mixtures at different pore states.Different from the shear-rate characteristics of natural sands or clay,the results showed that the peak strength of sand-foam mixtures under high vertical total stress(σ_(v)≥200 kPa)and low foam injection ratio(FIR30%)decreased with the increase in shear rate.Otherwise,the peak strength was not measurably affected by shear rates.The sand-foam mixtures in the residual state resembled low-viscous fluid with yield stress and the residual strength increased slightly with shear rates.In addition,the peak and residual strengths were approximately linear with vertical effective stress regardless of the total stress and FIR.The peak effective internal friction angle remained almost invariant in a low shear rate(γ′<0.25 s1)but decreased when the shear rate continued increasing.The residual effective internal friction angle was lower than the peak counterpart and insensitive to shear rates.This study unveiled the role of shear rates in the undrained shear strength of sand-foam mixtures with various FIRs and vertical total stresses.The findings can extend the understanding of the rate-dependent shear characteristics of conditioned soils and guide the decision-making of soil conditioning schemes in the EPB shield tunneling practice.

Effects of cosolvents on CO_(2) displacement of shale oil and carbon storage

Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent displacement of crude oil in shale nanopores and carbon storage was simulated and the influencing factors of displacement and storage were analyzed. It is shown that the attraction of the quartz wall to shale oil increases with the degree of hydroxylation. The higher the degree of quartz hydroxylation, the more difficult it is to extract the polar components of shale oil. Nanopore size also has a great impact on shale oil displacement efficiency. The larger the pore size, the higher the shale oil displacement efficiency. The closer the cosolvent molecules are to the polarity of the shale oil, the higher the mutual solubility of CO_(2) and shale oil. The more the non-polar components of shale oil, the lower the mutual solubility of CO_(2) and shale oil with highly polar cosolvent. Ethyl acetate is more effective in stripping relatively high polar shale oil, while dimethyl ether is more effective in stripping relatively low polar shale oil. Kerogen is highly adsorptive, especially to CO_(2). The CO_(2) inside the kerogen is not easy to diffuse and leak, thus allowing for a stable carbon storage. The highest CO_(2) storage rate is observed when dimethyl ether is used as a cosolvent, and the best storage stability is observed when ethyl acetate is used as a cosolvent.

Impact of clay particle reattachment on suffusion of sand-clay mixtures

The detached clay particles directly filtrated through the sand-clay mixture lead to suffusion;however,if the detached clay particles are subjected to reattachment,the degree of suffusion may be less significant.This study investigates the impact of clay particle reattachment on suffusion of sand-clay mixtures through laboratory soil-column experiments.The observed breakthrough curves(BTCs)of kaolinite,illite,and montmorillonite for 5 different column lengths(3 in,6 in,9 in,12 in,and 18 in;1 in=2.54 cm)indicated that a higher breakthrough concentration was observed as the column length(L)decreased for kaolinite and illite,whereas a reverse trend was observed for montmorillonite.In addition,the increase in the fraction of filtrated clay particles(Me)with an increase in L(Me=10.42%for L=3 in and Me=3.59%for L=18 in)for the sand-illite mixture indicated that the reattachment effect became more significant as the travel length of detached clay particles increased.The observed BTCs,retention profiles after injection,and fraction of filtrated clay presented herein suggest the need to incorporate the reattachment effect when assessing the suffusion of clay-containing soils.

NMR diffusion analysis of catalytic conversion mixtures from lignocellulose biomass using PSYCHE-iDOSY

The component analysis and structure characterization of complex mixtures of biomass conversion remain a challenging work.Hence,developing effective and easy to use techniques is necessary.Diffusion-ordered NMR spectroscopy(DOSY)is a non-selective and non-invasive method capable of achieving pseudo-separation and structure assignments of individual compounds from biomass mixtures by providing diffusion coefficients(D)of the components.However,the conventional 1H DOSY NMR is limited by crowded resonances when analyzing complex mixtures containing similar chemical structure resulting in similar coefficient.Herein we describe the application of an advanced diffusion NMR method,Pure Shift Yielded by CHirp Excitation DOSY(PSYCHE-iDOSY),which can record high-resolution signal diffusion spectra efficiently separating compounds in model and genuine mixture samples from cellulose,hemicellulose and lignin.Complicated sets of isomers(D-glucose/D-fructose/D-mannose and 1,2-/1,5-pentadiol),homologous compounds(ethylene glycol and 1,2-propylene glycol),model compounds of lignin,and a genuine reaction system(furfuryl alcohol hydrogenolysis with ring opening)were successfully separated in the diffusion dimension.The results show that the ultrahigh-resolution DOSY technique is capable of detecting and pseudo-separating the mixture components of C_(5)/C_(6) sugar conversion products and its derivative hydrogenation/hydrogenolysis from lignocellulose biomass.

Identification of Mixtures of Two Types of Body Fluids Using the Multiplex Methylation System and Random Forest Models

Objective Body fluid mixtures are complex biological samples that frequently occur in crime scenes,and can provide important clues for criminal case analysis.DNA methylation assay has been applied in the identification of human body fluids,and has exhibited excellent performance in predicting single-source body fluids.The present study aims to develop a methylation SNaPshot multiplex system for body fluid identification,and accurately predict the mixture samples.In addition,the value of DNA methylation in the prediction of body fluid mixtures was further explored.Methods In the present study,420 samples of body fluid mixtures and 250 samples of single body fluids were tested using an optimized multiplex methylation system.Each kind of body fluid sample presented the specific methylation profiles of the 10 markers.Results Significant differences in methylation levels were observed between the mixtures and single body fluids.For all kinds of mixtures,the Spearman’s correlation analysis revealed a significantly strong correlation between the methylation levels and component proportions(1:20,1:10,1:5,1:1,5:1,10:1 and 20:1).Two random forest classification models were trained for the prediction of mixture types and the prediction of the mixture proportion of 2 components,based on the methylation levels of 10 markers.For the mixture prediction,Model-1 presented outstanding prediction accuracy,which reached up to 99.3%in 427 training samples,and had a remarkable accuracy of 100%in 243 independent test samples.For the mixture proportion prediction,Model-2 demonstrated an excellent accuracy of 98.8%in 252 training samples,and 98.2%in 168 independent test samples.The total prediction accuracy reached 99.3%for body fluid mixtures and 98.6%for the mixture proportions.Conclusion These results indicate the excellent capability and powerful value of the multiplex methylation system in the identification of forensic body fluid mixtures.

Synthesis and Design of Distillation Columns for Wide-Boiling Binary Mixtures with Vapor Recompression Heat Pumps

The vapor recompression heat pump(VRHP) distillation technology offers significant improvements in energy efficiency for distillation systems with small temperature differences between the top and bottom of the column. However, the separation of wide-boiling binary mixtures leads to substantial temperature differences between the top and bottom of the column. This limits the applicability of conventional VRHP due to high capital costs and strict performance requirements of the compressor. To overcome these challenges and to accommodate compressor operating conditions, a novel synthesis and design method is introduced to integrate VRHPs with wide-boiling binary mixture distillation columns(WBMDCs). This method enables quick determination of an initial configuration for the integrated WBMDC-VRHP system and helps identify the optimum configuration with the minimum total annual cost. Two examples, namely the separation of benzene/toluene and isopropanol/chlorobenzene, are employed to derive optimum configurations of the WBMDC-VRHP and compare them with the WBMDC. A systematic comparison between the WBMDC-VRHP and WBMDC demonstrates the superior steady-state performance and economic efficiency of the WBMDC-VRHP.

The current pulses characteristics of the negative corona discharge in SF_(6)/CF_(4)mixtures

This paper presents the results of numerical investigation of the current pulses characteristics in SF_(6)/CF_(4)mixtures for the negative point-plane corona discharge.The pressure and the temperature of gas mixtures are 0.4 MPa and 300 K,respectively.The CF_(4)content varies from20%to 80%.The 2D axisymmetric geometry with point-plane electrodes is investigated,and the three drift-diffusion equations are solved to predict the characteristics of the negative corona discharge.In addition,Poisson’s equation is coupled with the above three continuity equations to calculate the electric field.In order to calculate the electron impact coefficients,including the Townsend ionization and attachment coefficients,as well as the mobilities and diffusion coefficients for electrons,the two-term Boltzmann equation is solved.The characteristics of three ionic species at five stages of the first current pulse in 60%SF_(6)-40%CF_(4)and20%SF_(6)-80%CF_(4)mixtures are selected to discuss the development mechanism of current pulses.Moreover,the reduced electric field strengths at the corresponding time instants are presented to help understand the discharge process.The current waveform and the total number of three species are compared in all the cases to analyze the effects of the CF_(4)content on the discharge.The reduced electric field strength is also helpful in understanding the effects of CF_(4)content.When the CF_(4)content increases to 80%,the discharge is more intensive and the pulse frequency also increases.

Analytical Study on the Effect of Electric Arc Furnace Dust(EAFD)on the Rutting of Asphalt Concrete Mixtures

As a byproduct of the steelmaking process,significant amounts of hazardous electric arc furnace dust(EAFD)are produced.Utilizing the solidification/stabilization technology with asphalt mix is one way to safeguard the environment from its negative effects.Rutting was used as an indicator to assess the asphalt mixture with EAFD since it is an important factor in pavement design.This study’s major goal is to ascertain how EAFD affects the rutting of asphalt-concrete mixtures.To evaluate the ideal asphalt content,the Marshall test method was applied to asphalt-concrete mixtures.EAFD was added to the asphalt cement in four different volume percentages as a binder addition.Then,using the Universal Testing Machine,participants were exposed to a replica of the rutting test(UTM).Experiments were conducted at 25℃,40℃ and 55℃,and at frequencies of 1 Hz,4 Hz and 8 Hz.Rutting was measured for each specimen.Test results showed that rut depth has a negative correlation with EAFD%and a positive correlation with temperature.The use of EAFD has dual advantages,protecting the environment from the adverse impact of EAFD and reducing the cost of asphalt mix without jeopardizing pavement performance.

蚬子外壳仿生表面减阻结构的设计与分析

受天然生物蚬子在泥沙环境中优异的运动能力的启发,提出了仿生蚬子表面形貌减阻方法,并根据其外壳表面形貌特征的显微图像设计了仿生表面减阻结构,利用CFD数值模拟方法中的多相流Mixture模型对设计的3种仿生表面结构进行横向仿真模拟并与光滑表面结构进行减阻效果对比。结果表明,在不同的两相流流速下,3种仿生表面结构在横向模拟中都具有一定的减阻特性,且以棱纹结节表面结构的减阻性能最佳。

弹塑性多孔介质流固耦合新理论:混合耦合理论

在全球气候变化和双碳政策的大背景下,多孔介质中固体的变形和流体的输运问题变得尤为重要。然而,在多孔介质中建立流固耦合模型仍面临的挑战之一是需要考虑跨越宏观尺度到纳米尺度的耦合作用。本文利用基于非平衡热力学的混合耦合理论,提出了一个弹塑性多孔介质流固耦合新模型,在同一个理论框架内研究了弹性变形、塑性变形和液体渗流之间跨尺度的耦合,考虑了耗散过程中的熵产,并利用Helmholtz自由能连接宏观尺度上的力学变形和纳米尺度上的液体输运之间的相互作用。在应力-应变关系中采用了弹塑性刚度系数以反映塑性的影响。同时,经典的达西定律扩展为可考虑固体的塑性变形。通过与文献中模型的比较,验证了该模型的有效性。最后,数值分析表明在多孔介质的流固耦合中塑性变形具有比较显著的影响。

植物油微胶囊沥青混合料的微观力学性能及自愈合机制

为了研究植物油微胶囊沥青混合料的微观力学性能及自愈合机制,利用分子动力学方法基于12分子沥青模型构建沥青微裂缝模型,采用植物油提取物油酸、亚油酸以及石油基再生剂乙基四氢化萘作为芯材,探究三种芯材释放后沥青微裂缝的自愈合进程,计算沥青分子的自扩散系数并分析不同芯材的作用机制,同时构建沥青-集料模型,采用粘聚能、粘附能、粘附强度等指标分析融入不同芯材后沥青-集料界面的微观力学性能。结果表明:芯材的释放加速了沥青分子的自扩散,提高了微裂缝的自愈合能力,且微裂缝自愈合能力随温度的升高而增强;与芯材融合后老化沥青的粘聚能和粘附能分别提高了37.2%和36.8%以上,并且老化沥青-集料界面的粘附强度增加;与石油基再生剂相比,植物油能更好地促进微裂缝的愈合。通过分子动力学技术可以更深入地探查微胶囊沥青路面的自愈合机制,从而为微胶囊芯材的设计与选择提供可行的方法。

参姜止痢合剂治疗仔猪黄痢的临床疗效评价

为验证参姜止痢合剂治疗仔猪黄痢的临床疗效,从兰州周边养猪场搜集疑似病例,经流行病学调查、临床症状观察作出初步诊断,通过实验室细菌学检查进行确诊后,采用参姜止痢合剂进行治疗,观察给药后病猪精神状态、饮食和腹泻情况,采用普通血平板培养基和大肠杆菌显色培养基测定给药前后仔猪粪便中大肠杆菌的数量。结果显示,用药治疗后的仔猪精神状态明显好转或恢复正常,病猪粪便中大肠杆菌数量明显减少,3个养猪场(景泰县王德香养猪场、甘肃蟾慕农业科技有限责任公司和永登县苗中俊养猪场)的黄痢治愈率分别为87.6%、89.1%和84.1%。结果提示,参姜止痢合剂治疗仔猪黄痢效果较好,为今后研发新药提供了试验依据。

补肾活血序贯法对薄型子宫内膜大鼠内膜形态及VEGF、Vimentin、CK12蛋白表达的影响

目的:观察补肾活血序贯法中药对薄型子宫内膜大鼠内膜形态、血管内皮生长因子(VEGF)蛋白、波形蛋白(Vimentin)和组织细胞角蛋白12(cytokeratin 12,CK12)表达的影响。方法:将SPF级雌性SD大鼠连续灌胃羟基脲8 d复制肾虚薄型子宫内膜模型,造模成功后50只大鼠随机分为模型组、中药低剂量组、中剂量组、高剂量组及补佳乐组(阳性对照组)每组10只,另取10只大鼠为假手术组。假手术组和模型组灌胃等量蒸馏水,补佳乐组灌胃补佳乐0.3 mg/kg。其余3组动情期分别灌胃给予低、中、高剂量的消癥合剂;动情前期、动情后期和动情间期分别灌胃给予低、中、高剂量的养膜助孕包,连续给药3个动情周期,共15 d。干预结束后,HE染色观察大鼠子宫内膜形态;免疫组化检测大鼠子宫内膜VEGF、Vimentin和CK12表达。结果:模型组大鼠子宫内膜厚度、腺体数和血管数明显低于假手术组(P<0.01)。中药中、高剂量组及补佳乐组大鼠子宫内膜厚度、腺体数和血管数明显高于模型组(P<0.05或0.01)。中药中、高剂量组和补佳乐组大鼠子宫内膜组织VEGF的表达量均明显多于模型组(P<0.01),中药高剂量组子宫内膜组织Vimentin蛋白表达量明显高于模型组(P<0.01),中药低、中、高剂量组和补佳乐组子宫内膜组织CK12的表达明显多于模型组(P<0.05或0.01)。结论:补肾活血序贯法中药可以增加肾虚薄型子宫内膜模型大鼠的子宫内膜厚度及内膜组织VEGF、Vimentin、CK12蛋白表达。

基于EDEM的核桃壳仁混合物振动筛分级工艺优化

为提高核桃壳仁混合物的分级效果,对现有核桃壳仁混合物分级设备进行三维实体建模,利用EDEM软件模拟核桃壳仁混合物的分级过程,以筛面上物料的运动速度、质量以及各等级颗粒在统计区域的数量为指标,以振幅、振动频率、振动方向角、筛面倾角为考察因素,对振动筛分级工艺进行优化。结果表明:在振动频率12 Hz、振幅5 mm、振动方向角45°、筛面倾角4°的工艺参数组合下,各等级核桃壳仁的透筛率最高,分级效果最好。

含R1234yf混合工质汽液相平衡的混合规则评估与预测研究

含R1234yf混合工质具有系统性能优良且对环境友好的特点,在当前制冷剂迭代中受到了广泛关注。汽液相平衡性质是混合工质的基础热物理性质,其理论计算至关重要。为提高含R1234yf混合工质汽液相平衡数据的计算精度,选取PR状态方程结合vdW、WS、MHV1三种混合规则和NRTL活度系数模型评估了16种含R1234yf二元混合工质的汽液相平衡性质。结果表明,WS混合规则和MHV1混合规则计算性能优于vdW混合规则;vdW混合规则对大多数混合工质计算性能较好。最后提出一种预测模型预测含R1234yf混合工质汽液相平衡性质,预测的相对压力偏差值为0.49%,气相摩尔分数绝对偏差值为0.0031,预测偏差满足工程应用。

基于模态理论和改进GMM的声发射源识别研究

基于模态声发射信号理论,提出了一种利用声学对数倒谱统计参数作为声发射信号特征参数的分析与提取方法。从声发射信号多模态特性出发,提出了一个基于改进高斯混合模型的声发射源信号识别系统。理论分析和实验结果表明,该方法能准确地判断声发射信号源,不仅能够应用于突发型声发射信号的识别,而且可以应用于连续型声发射信号的识别。

基于MFCC和GMM的瓷砖空鼓率识别系统及方法

针对瓷砖因内部空鼓而引起的松动、脱落等质量问题或其他安全隐患问题,研制了一套用于瓷砖空鼓率识别的试验系统。该系统采用梅尔倒谱系数(MFCC)法提取瓷砖敲击声的特征参数,再用高斯混合模型(GMM)法对MFCC特征参数进行分类和识别。试验结果表明,采用MFCC和GMM相结合的方法,可以对瓷砖空鼓情况进行有效识别,该方法具有良好的应用前景。