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Quantifying relationships between subsidence and longwall face advance using DInSAR

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International Journal of Mining Science and Technology 2021年第1期31卷 91-94页

作者： Bailey S.simmons Jessica M.Wempen Department of Mining Engineering University of UtahUT 84112United States

Surface subsidence that results from longwall mining can be large magnitude and can affect significant *** methods for subsidence monitoring include leveling,global positioning system(GPS),and photogrammetric *** sensing techniques including,aerial LiDAR,terrestrial laser scanning,and satellite-based Differential Interferometric Synthetic Aperture Radar(DInSAR),are also used to measure deformation associated with *** data are different than data from conventional subsidence *** capture data over large areas(hundreds of kilometers),and each pixel(data point)in an image quantifies the average displacement over an area of square *** data can have fairly high time resolution;imaging periods typically range from weeks to *** data can be useful to monitor subsidence sequentially over short *** monitoring subsidence may help define if caving is progressing normally and can establish relationships between surface deformation and longwall face advance,which has potential to help quantify possible risks to mine *** this study,subsidence at a longwall trona mine is monitored over short periods,typically 12 days,as the longwall face is advanced through a panel.C-band interferometric wide swath synthetic aperture radar(SAR)images from the sentinel satellites are used to quantify the *** onset of subsidence occurs close in time to the beginning of the longwall face advance,and overall,the development of subsidence closely follows the longwall face advance.

关键词： DInSAR Subsidence Monitoring Longwall Trona

Processing Compressed Expanded Natural Graphite for Phase Change Material Composites

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Journal of Thermal Science 2023年第3期32卷 1213-1226页

作者： Alexander BULK Adewale ODUKOMAIYA Ethan simmons Jason WOODS National Renewable Energy Laboratory 15013 Denver West ParkwayGoldenCO 80401USA

Phase change materials(PCMs)are used in various thermal energy storage applications but are limited by their low thermal *** method to increase conductivity involves impregnating organic PCMs into highly porous conductive matrix *** these materials,compressed expanded natural graphite(CENG)matrices have received the most *** this attention,the effect that CENG processing has on PCM saturation and overall matrix thermal conductivity has not been fully ***,the effect of the heat treatment process used to expand intercalated graphite flakes is evaluated *** heat treatment temperatures yielded higher saturation rates and overall saturation at similar matrix *** example,increasing temperature from 300℃to 700℃resulted in approximately 60%-70%increase in pore saturation after 100 minutes of *** exposure time to heat treatment had less of an effect on PCM *** exposure time had negligible effect above 30 min and above 500℃heating ***,because the expanded graphite was found to oxidize around 700℃,the use of longer exposure time in manufacturing applications can be beneficial if a shortened impregnation time is *** treatment conditions did not impact thermal *** composite latent heat of fusion was also reduced approximately proportionally to the PCM mass fraction.A local maximum in axial thermal conductivity was observed at around 83%porosity,which is similar to previous *** observed conductivity at this maximum was a factor of 81 times greater than the conductivity of the PCM.

关键词： phase change materials thermal energy storage compressed expanded natural graphite thermal conductivity enhancement porous material sorptivity composite matrix

Inundative field releases and evaluation of three predators for Bemisia tabaci （Hemiptera： Aleyrodidae） management in three vegetable crops

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Insect Science 2011年第2期18卷 195-202页

作者： Alvin M. simmons Shaaban Abd-Rabou USDA ARS U.S. Vegetable Laboratory Charleston South Carolina ARC PPRI Dokki Giza Egypt

The sweetpotato whitefly, Bemisia tabaci （Gennadius）（Hemiptera： Aleyrodidae）, is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator （Coccinella undecimpunctata L. [Coleoptera： Coccinellidae]）, a common green lacewing predator （Chrysoperla carnea Stephen [Neuroptera： Chrysopidae]）, and a mirid predator （Macrolophus caliginosus [Wagner] [Hemiptera： Miridae]） were independently made in three vegetable crops （cabbage [Brassica oleracea var. capitata L.], cucumber [Cucumis sativus L.], and squash [Cucurbita pepo L.]） for the management of the sweetpotato whitefly. Approximately 1 million to 2.5 million larvae or nymphs of each predator were released in the vegetable crops during 20 weeks. Whitefly populations were reduced by ≈ 25%-45% during most of the season in each crop where each predator was released. The effect of each predator was similar on whitefly population reduction. Late in the season （October） when whitefly populations were low, generally no benefit was obtained from releasing the predators. Numbers of predators recovered during sampling in all crops were greatest for C. carnea, but this corresponded with the fact that more individuals of this predator were released than any other predator in the experiment. These results help define the utility of these natural enemies for managing B. tabaci in vegetable crops.

关键词： Bemisia tabaci Chrysoperla carnea Coccinella undecimpunctata Macrolophus caliginosus inundative release sweetpotato whitefly

Application of DNA barcodes in Hedyotis L.(Spermacoceae,Rubiaceae)

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Journal of Systematics and Evolution 2011年第3期49卷 203-212页

作者： Mark P.simmons Paul Pui-Hay BUT Pang-Chui SHAW Department of Biology Colorado State University School of Life Sciences The Chinese University of Hong Kong

The potential application of DNA barcodes of plastid(matK,trnH-psbA,petD,and rbcL) and nuclear(internal transcribed spacer(ITS) of rDNA) DNA regions was investigated for 25 Hedyotis *** ITS showed the best species discrimination by resolving 23 of the species as exclusive lineages with no shared alleles between any of the 24 distinct species(*** and *** are not supported as distinct species based on our molecular and morphological data).Conversely,rbcL performed the worst and only resolved 10 of the species as exclusive lineages,and 10 species with shared *** ITS has the advantage of high PCR amplification success and it provides good intra-and interspecific variation distribution *** most powerful plastid markers were petD and trnH-psbA,but we could amplify and sequence trnH-psbA for only 83% of the accessions *** of ITS and petD performed extremely well,with all 24 of the distinct species resolved as exclusive lineages and no shared alleles between any of the distinct *** therefore recommend ITS,or a combination of ITS and petD,as the standard DNA barcode in Hedyotis,but acknowledge that there are no shared alleles between distinct species for matK and rbcL combined.

关键词： DNA barcode Hedyotis molecular identification Rubiaceae taxonomy.

Groundwater Recharge and Mixing in Arid and Semiarid Regions:Heihe River Basin,Northwest China

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Acta Geologica Sinica(English Edition) 2016年第3期90卷 971-987页

作者： CAO Guoliang ZHENG Chunmiao Craig T.simmons Institute of Water Sciences Peking UniversityBeijing 100871China School of the Environment&National Centre for Groundwater Research and Training Adelaide SA 5001Australia School of Environmental Science and Engineering South University of Science and Technology of ChinaShenzhen 518055China Department of Geological Sciences University ofAlabamaTuscaloosaAlabama 35487USA

A sound understanding of groundwater recharged from various sources occurring at different time scales is crucial for water management in arid and semi-arid river basins. Groundwater recharge sources and their geochemical evolution are investigated for the Heihe River Basin （HRB） in northwest China on the basis of a comprehensive compilation of geochemical and isotopic data. Geochemical mass- balance modeling indicates that mountain-block recharge accounts for a small fraction （generally less than 5%） of the shallow and deep groundwater sustaining the oasis, whereas infiltration of rivers and irrigation water contribute most of the groundwater recharge. Dedolomitization is the primary process responsible for the changes in groundwater chemical and carbon isotope compositions from the piedmont to the groundwater discharge zone, where the dedolomitization is very likely enhanced by modern agricultural activities affecting the shallow groundwater quality. Analysis of radioactive isotopes suggests that these primary recharge sources occur at two different time scales. Radiocarbon-derived groundwater age profiles indicate a recharge rate of approximately 12 mm/year, which probably occurred during 2000-7000 years B.P., corresponding to the mid-Holocene humid period. The recharge of young groundwater on the tritium-dated time scale is much higher, about 360 mm/year in the oasis region. Infiltration from irrigation canals and irrigation return flow are the primary contributors to the increased young groundwater recharge. This study suggests that groundwater chemistry in the HRB has been influenced by the complex interaction between natural and human-induced geochemical processes and that anthropogenic effects have played a more significant role in terms of both groundwater quantity and quality.

关键词： Heihe River Basin groundwater recharge groundwater mixing isotope hydrology

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企业如何有效地展示个性

商学院 2024年第6期 15-15页

作者： Lee simmons 斯坦福商学院

在个人生活和职业生涯中,我们常常会面临着一个矛盾:既希望融入社会,受到认可,又渴望展现自身的独特性,脱颖而出。这种挑战不仅存在于个人,也存在于企业。斯坦福商学院组织行为学教授阿米尔·戈德堡指出,企业必须在与众不同和符合潮流... 详细信息

在个人生活和职业生涯中,我们常常会面临着一个矛盾:既希望融入社会,受到认可,又渴望展现自身的独特性,脱颖而出。这种挑战不仅存在于个人,也存在于企业。斯坦福商学院组织行为学教授阿米尔·戈德堡指出,企业必须在与众不同和符合潮流之间找到平衡点。他认为,存在一个最佳的差异化水平,可以在满足行业规范的同时展现独特性。

关键词：组织行为学差异化阿米尔平衡点行业规范融入社会职业生涯斯坦福商学院

Screening large numbers of recombinant plasmids:modifications and additions to alkaline lysis for greater efficiency

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Progress in Natural Science:Materials International 2006年第11期16卷 1231-1232页

作者： N.V.CHANDRASEKHARAN Daniel L.simmons Department of Chemistry and Biochemistry Brigham Young UniversityProvoUtah 84602USA

Selecting bacteria transformed with recombinant plasmid is a laborious step in gene cloning experiments. This selection process is even more tedious when large numbers of clones need to be screened. We describe here modifications to the ultra fast plasmid preparation method described previously by Law and Crickmore. The modified method is coupled to an efficient PCR step to rapidly determine orientation of the inserts. Compared to traditional methods of analysis requiring growth of overnight cultures, plasmid isolation and restriction enzyme digestion to determine orientation this procedure allows for the analysis and storage of a large number of recombinants within a few hours.

关键词： plasmid preparation polymerized chain reaction

Sensitivity of Medium-Range Weather Forecasts to the Use of Reference Atmosphere

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Advances in Atmospheric Sciences 1990年第3期7卷 275-293页

作者：陈嘉滨 A.J.simmons Institute of Atmospheric Physics Academia Sinica Beijing 100080 European Centre for Medium-Range Weather Forecasts Reading U.Kn this paper the authors develop the earlier work of Chen Jiabin et al. (1986). In order to reduce spectral truncation errors the reference atmosphere has been introduced in ECMWF model and the spectrally-represented variables temperature geopotential height and orography are replaced by their deviations from the reference atmosphere. Two modified semi- implicit schemes have been proposed to alleviate the computational instability due to the introduction of reference atmosphere. Concerning the deviation of surface geopotential height from reference atmosphere an exact computational formulation has been used instead of the approximate one in the earlier work. To re duce aliasing errors in the computations of the deviation of the surface geopotential height a spectral fit has been used slightly to modify the original Gaussian grid-point values of orography.A series of experiments has been performed in order to assess the impact of the reference atmosphere on ECMWF medium- range forecasts at the resolution T21 T42 and T63. The results we have obtained reveal that the reference atmosphere introduced in ECMWF spectral model is generally beneficial to the mean statistical scores of 1000-200 hPa height 10-day forecasts over the globe. In the Southern Hemisphere it is a clear improvement for T21 T42 and T63 throughout the 10-day forecast period. In the Northern Hemisphere the impact of the reference atmos phere on anomaly correlation is positive for resolution T21 a very slightly damaging at T42 and almost neutral at T63 in the range of day 1 to day 4. Beyond the day 4 there is a clear improvement at all resolutions.

In this paper, the authors develop the earlier work of Chen Jiabin et al. (1986). In order to reduce spectral truncation errors, the reference atmosphere has been introduced in ECMWF model, and the spectrally-represented variables, temperature, geopotential height and orography, are replaced by their deviations from the reference atmosphere. Two modified semi- implicit schemes have been proposed to alleviate the computational instability due to the introduction of reference atmosphere. Concerning the deviation of surface geopotential height from reference atmosphere, an exact computational formulation has been used instead of the approximate one in the earlier work. To re duce aliasing errors in the computations of the deviation of the surface geopotential height, a spectral fit has been used slightly to modify the original Gaussian grid-point values of orography.A series of experiments has been performed in order to assess the impact of the reference atmosphere on ECMWF medium- range forecasts at the resolution T21, T42 and T63. The results we have obtained reveal that the reference atmosphere introduced in ECMWF spectral model is generally beneficial to the mean statistical scores of 1000-200 hPa height 10-day forecasts over the globe. In the Southern Hemisphere, it is a clear improvement for T21, T42 and T63 throughout the 10-day forecast period. In the Northern Hemisphere, the impact of the reference atmos phere on anomaly correlation is positive for resolution T21, a very slightly damaging at T42 and almost neutral at T63 in the range of day 1 to day 4. Beyond the day 4 there is a clear improvement at all resolutions.

关键词： Sensitivity of Medium-Range Weather Forecasts to the Use of Reference Atmosphere ECMWF