搜索到333768篇“ CALCULATING“的相关文章
Improved Approaches to Calculating Dilution and Attenuation Factor in Contaminant Hydrogeology
2024年
Dilution and attenuation factor (DAF) has a major influence on soil-to-groundwater screening level calculation for protection of contaminant migration from soil into groundwater at solid waste management units (SWMUs). Risk assessment guidance prepared by U.S. Environmental Protection Agency for site investigation and remediation suggests a default DAF of 20. If the base assumptions included in the default DAF are recognized to be not representative of site conditions at a SWMU, calculation of site-specific DAF is recommended when sufficient data are collected to justify using a different DAF value for development of soil screening levels. Commonly used methods of calculating DAF include analytical and numerical simulations that often require too many parameters to be obtained in practice. This paper proposes a probability method to develop site-specific DAF. The approach uses data that are readily available through field reconnaissance and site-specific investigation. A case study is presented in which the probability method was applied to an actual SWMU, and the calculated DAF is compared with that calculated from a dilution method. The probability-based DAF is 67 at 90% probability percentile, which is comparable to the dilution-based DAF of 76. Based on the calculated site-specific DAFs, SSLs could be developed for the contaminants of potential concern and used for evaluation of migration pathways from a contamination source through soil to groundwater. .
Xiangquan LiChunchao ZhangWanfang Zhou
Calculating the Crystallite Size of Microsorum scolopendria AgCl Nanoparticles and Their Biological Activities
2024年
In this work, AgCl nanoparticles were synthesized from Microsorum scolopendria (MS) aqueous extract and AgNO3 solution. Preliminary confirmation was a color change from a light brown to a dark-colored solution and a UV-Vis spectra surface plasmon resonance peak at 427 nm. Measured vibrational frequencies at 1713 cm1 and 1030 cm1 for C-O stretching of carboxylic acid or aliphatic ketone, and 1547 cm1 for possibly N-O stretching of nitro compounds by Infrared (FTIR) analysis explain the possible biomaterial electronegative species or functional groups responsible for the reduction of Ag ( 1) to Ag (0) for the formation of MS-AgCl nanoparticles. XRD analysis studies revealed that these particles contained face-centered cubic crystallites of metallic AgCl of 100 % with an average calculated crystallite size range of 30.34 nm (SD = 5.10 nm) by Scherrers equation and a calculated crystallite size of 66.04 nm with a lattice strain of 0.00175 nm by Williamson Hall equation. The measured albumin denaturing activity of MS-AgCl nanoparticles gave an IC50 value of 26.70 g/mL and 1.35 g/mL for the positive control diclofenac. Additionally, the measured ability of phosphomolybdate complex formation, the antioxidant IC value of MS-AgCl nanoparticles was 35.29 g/mL, and positive control ascorbic acid was 13.91 g/mL. In all, using MS fern frond aqueous extracts, this preliminary work confirms MS-AgCl nanoparticles as potential therapeutic agents for oxidative stress, inflammatory problems, and related diseases.
Christian Nanga ChickMohammed MahdalyPhillippe Belle Ebanda KediKiuchi SonokoFrancois Eya’ane Meva
关键词:SNPSIRUV-VISANTIOXIDANT
On calculating glacial isostatic adjustment
2024年
Modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity profile.Here,we compare two methods for calculating the viscoelastic response to surface loading.In one,the elastic equation of motion is converted to a viscoelastic equation using the Correspondence Principle.In the other,elastic deformation is added to the viscous flow as isostatic adjustment proceeds.The two modeling methods predict adjustment histories that are different enough to potentially impact the interpretation of the observed glacial isostatic adjustment(GIA).The differences arise from buoyancy and whether fluid displacements are subjected to hydrostatic pre-stress.The methods agree if they use the same equations and boundary conditions.The origin of the differences is determined by varying the boundary conditions and pre-stress application.
L.M.Cathles
Dynamic-based model for calculating the boulder impact force in debris flow
2024年
The boulder impact force in debris flow is generally calculated by static methods such as the cantilever beam models.However,these methods cannot describe the dynamic scenario of boulder collision on structures,so the inertia and damping effects of the structures are not involved causing an overestimation on the boulder impact force.In order to address this issue,a dynamic-based model for calculating the boulder impact force of a debris flow was proposed in this study,and the dynamic characteristics of a cantilever beam with multiple degrees of freedom under boulder collision were investigated.By using the drop-weight method to simulate boulders within debris flow,seven experiments of drop-weight impacting the cantilever beam were used to calibrate the error of the dynamicbased model.Results indicate that the dynamic-based model is able to reconstruct the impact force history on the cantilever beam during impact time and the error of dynamic-based model is 15.3%in calculating boulder impact force,significantly outperforming the cantilever beam model’s error of 285%.Therefore,the dynamic-based model can overcome the drawbacks of the static-based models and provide a more reliable theoretical foundation for the engineering design of debris flow control structures.
YANG ChaopingZHANG ShaojieYIN YuepingYANG HongjuanWEI Fangqiang
湿陷性黄土地基中桩基负摩阻力计算新方法
2024年
负摩阻力对湿陷性黄土地基中桩基的承载变形性状具有重要影响,现行桩基规范及黄土规范推荐的负摩阻力计算方法不能反映黄土桩基负摩阻力的实际性状。对近30年来在黄土地区开展的钢筋混凝土灌注桩现场浸水试验实测数据进行统计,分析黄土浸水完成后桩身中性点深度、桩身最大负摩阻力深度及负摩阻力系数与桩长径比的关系,通过线性拟合得到了中性点深度比、最大负摩阻力深度比及负摩阻力系数与桩长径比的经验表达式,提出湿陷性黄土地基中桩基负摩阻力计算的新方法。新方法用三角形表示负摩阻力沿深度的分布,能反映负摩阻力从桩顶向下先逐渐增大、达到最大值后随深度增加逐渐减小、最终在中性点处减小为零的分布特征。将提出的方法、桩基规范及黄土规范方法的计算结果与实测结果进行对比,结果表明,桩基规范预测的中性点深度比优于黄土规范,黄土规范预测的最大下拉荷载优于桩基规范,而用新方法计算的负摩阻力最接近实测结果。
赵敏曹卫平
关键词:湿陷性黄土钢筋混凝土桩负摩阻力计算方法
基于格网锥形方向的关系模型计算方向相似性研究
2024年
针对方向关系矩阵在定量计算空间对象方向相似关系方面存在的表达能力、多尺度地图数据下应用能力不足的问题,提出一种格网锥形方向关系模型,完成对空间对象方向关系的定量表达。对同尺度下格网锥形方向关系模型的表达能力进行试验分析,并对不同尺度下格网锥形方向关系模型的应用能力进行分析,分析对比后验证了本文方法可行,空间方向相似性度量结果和人们的认知结果一致,可应用于制图综合、空间数据查询更新、空间数据变化检测等任务。
宗琴陈慧刘文萍
关键词:计算方法
Developing a method for calculating the mean outdoor radiant temperature for thermal stress in Guangzhou
2024年
Cities around the world are exposed to increasing heat stress as a result of the heat island effect exacerbated by extreme weather events,population growth and increased urbanization.To promote outdoor activities and protect human health,there is an urgent need for a tool to assess the outdoor thermal environment.While the air temperature(Ta)and relative humidity(RH)are usually available from weather stations,but the mean radiant temperature(MRT)cannot.The MRT is a key variable in determining outdoor thermal comfort.Therefore,it is necessary to develop a simple and accurate method for calculating MRT,in order to compute the corresponding thermal indices,which can be used to assess the thermal environment more accurately.This study was conducted at a university in Guangzhou,China.Four different ground-cover surfaces(concrete,asphalt,lawn,and granite)were selected for study.The T_(a),black-globe temperature(T_(g)),long-wave(L),and short-wave(K)radiation in six directions,and wind speeds(V_(a))were measured under unshaded conditions.The MRT obtained by the six-direction integral method was used as the base value and regression analyses were performed with Ta,K↓(downward short-wave),and Va.In addition,the six indices—significance(P),linear regression coefficient(R^(2)),consistency index(d),root mean square error(RMSE),mean bias error(MBE),and mean absolute error(MAE)—were used for quantitative analysis to explore the feasibility of this method.This study compared five calculation models on MRT:MRTSDIM(six-direction integral method),MRTBGTM-Va-0.1Hz(black-globe thermometer method,0.1 Hz wind speed measurement frequency),MRTBGTM-Va-10Hz(black-globe thermometer method,10 Hz wind speed measurement frequency),MRTBGTM-P(polynomial regression based on black-globe thermometer method),and MRTSDIM-P(polynomial regression based on six-direction integral method).The MRTSDIM was used as a baseline value,and the values obtained by other four methods were discussed and validated separately.The results show that the calculatio
Xiaoqing ZhouTianwei TangXiwen FengNaiping GaoYanping YangZhaosong Fang
汽车门盖冲压外板翻边高度测量计算方法研究
2024年
门盖的冲压外板翻边高度直接影响着门盖总成包边后的表面质量和尺寸精度。在生产中,必须精确测量翻边高度,以确保产品质量。文章总结了目前采用的手工测量、按切边测量和按距离测量三种翻边高度测量计算方法存在的问题,结合生产工艺重新定义了翻边高度,并建立了新的数学计算方法。通过利用ATOS Scanbox光学测量设备,实现了该方法并得到准确的翻边高度测量和计算结果。同时通过对ATOS测量软件进行二次开发,实现了该方法计算过程的自动化。新的翻边高度计算方法不但实现翻边高度的准确测量,且相较于手工测量,在新车型项目期间可节约人工工时200 h,提升了质量优化的效率。
朱晓波曾忞
An integrated computational method for calculating dynamic thermal bridges of building facades in tropical countries
2024年
Identifying thermal bridges on building façades has been a great challenge for architects,especially during the conceptual design stage.This is not only due to the complexity of parameters when calculating thermal bridges,but also lack of feature integration between building energy simulation(BES)tools and the actual building conditions.For example,existing BES tools predominantly calculate thermal bridges only in steady state without considering the temperature dynamic behaviour of building outdoors.Consequently,relevant features such as thermal delay,decrement factor,and operative temperature are often neglected,and this can lead to miscalculation of energy consumption.This study then proposes an integrated method to calculate dynamic thermal bridges under transient conditions by incorporating field observations and computational simulations of thermal bridges.More specifically,the proposed method employs several measurement tools such as HOBO data logger to record the actual conditions of indoor and outdoor room temperature and thermal cameras to identify the surface temperature of selected building junctions.The actual datasets are then integrated with the simulation workflow developed in BES tools.This study ultimately enables architects not only to identify potential thermal bridges on existing building façades but also to support material and geometric exploration in early design phase.
Miktha Farid AlkadriMuhammad Rafif Cahyadi AgungFrancesco De Luca
Calculating the Excitation Temperature for H_2CO Absorption Lines in Molecular Clouds
2024年
The excitation temperature T_(ex)for molecular emission and absorption lines is an essential parameter for interpreting the molecular environment.This temperature can be obtained by observing multiple molecular transitions or hyperfine structures of a single transition,but it remains unknown for a single transition without hyperfine structure lines.Earlier H_(2)CO absorption experiments for a single transition without hyperfine structures adopted a constant value of T_(ex),which is not correct for molecular regions with active star formation and H II regions.For H_(2)CO,two equations with two unknowns may be used to determine the excitation temperature T_(ex)and the optical depthτ,if other parameters can be determined from measurements.Published observational data of the4.83 GHz(λ=6 cm)H_(2)CO(1_(10)-1_(11))absorption line for three star formation regions,W40,M17 and DR17,have been used to verify this method.The distributions of T_(ex)in these sources are in good agreement with the contours of the H110αemission of the H II regions in M17 and DR17 and with the H_(2)CO(1_(10)-1_(11))absorption in W40.The distributions of T_(ex)in the three sources indicate that there can be significant variation in the excitation temperature across star formation and H II regions and that the use of a fixed(low)value results in misinterpretation.
Jia BuJarken EsimbekJianjun ZhouToktarkhan KomeshXindi TangDalei LiYuxin HeKadirya TursunDongdong ZhouErnar ImanalySerikbek Sailanbek
关键词:ISMCLOUDS

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高正红
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李泽民
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供职机构:中国科学院文献情报中心
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田锐仪
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研究主题:DRESS CALCULATING PRICE 英语