XANES analysis of the mechanisms of arsenic removal in biological iron and manganese treatment unit

Biological iron and manganese removal utilizing indigenous iron and manganese oxidizing bacteria （IRB hereafter） in groundwater can also be applied to arsenic removal according to our pilot-scale test. The arsenic removal probably occurred through sorption and complexation of arsenic to iron and manganese oxides formed by enzymic action of IRB. We investigated the chemical properties of iron and manganese oxides in IRB floc and the valence state of arsenic sorbed to the floc to clarify the mechanisms of the arsenic [especially As （Ⅲ）] removal. The floc samples were collected from two drinking water plants using IRB （Jyoyo and Yamatokoriyama, Japan）, and our pilot - scale test site where arsenic and iron removal using IRB is under way （Mukoh, Japan）. The Jyoyo and Yamatokoriyama IRB floc samples were subjected to As （Ⅲ） and As（Ⅴ） sorption experiments. The elemental composition of the floc samples was measured. XANES spectra were collected on As, Fe and Mn K-edges at synchrotron radiation facility Spring 8 （Hyogo, Japan）. FT-IR and the X-ray diffraction spectra of the samples were also obtained. The IRB floc contained ca. 35 % Fe, 0.3%-3.5% Mn and 2%-6% P. The samples were highly amorphous and contained ferrihidrites and hydrated iron phosphate. According to XANES analyses of IRB, As associated with IRB was in ＋5 valence state when As （Ⅲ） （or As （Ⅴ）） was added in laboratory sorption test, Fe in ＋3 valence state, and Mn a mixture of＋3 and ＋4 valence states. Small shift was observed in the XANES spectra of IRB on As K-edge as the equilibration time of the sorption experiment was increased. Gradual oxidation of a small amount of As （Ⅲ） associated with IRB or change in arsenic binding with sorption site were the probable mechanism.     

Geochemical characteristics from tests of four modern planktonic foraminiferal species in the Indonesian Throughflow region and their implications

Test geochemistry of planktonic foraminifera is an indispensable tool in reconstructing past ocean hydrological changes. It is essential to investigate region-specific implications of test geochemistry,although those established from other regions can be broadly applied. In this study, characteristics of6180 and Mg/Ca from tests of four planktonic foraminiferal species, Globigerinoides ruber sensu stricto(s.s.), Globigerinoides sacculifer, Pulleniatina obliquiloculata and Neogloboquadrina dutertrei, from 60 coretop sediment samples retrieved from the Indonesian Throughflow(ITF) region were studied. These geochemical data were compared with modern hydrographic profiles in order to assess their relations and to investigate potential implications of test geochemical parameters in reconstructing past oceanographic change in the ITF region. Calcification depths of these four species were first estimated based on comparison between measured test δ180 and predicted calcite δ¹⁸O that was calculated from modern temperature and salinity. The results indicate that G. ruber s.s. and G. sacculifer calcify within the mixedlayer at 0-50 m and 20-75 m, respectively, whereas P. obliquiloculata and N. dutertrei calcify within the thermocline at around 75 to 125 m. A combined study of excess Mg/Ca(difference between measured and predicted Mg/Ca) and salinity suggests that salinity exerts a negligible impact on test Mg/Ca of these foraminiferal species in the ITF region. Comparison of test Mg/Ca-derived temperatures with temperature profiles of the upper 200 m of the water column from the seas of the ITF region also indicate calcification depths of these species, which match well with the above estimations using test δ¹⁸O. It further indicates that G. sacculifer may be more sensitive in reflecting changes in the depth of the mixedlayer, highlighting a potential use of Mg/Ca temperature difference between G. ruber s.s. and G. sacculifer in reconstructing the depth of the mixed-layer in the ITF region.     

Variability of Nonionellina labradorica Dawson in Surface Sediments from Kongsfjorden, West Spitsbergen

Kongsfjorden is a fjord in Spitsbergen (Svalbard archipelago) that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems. To decipher the effect of the lateral advection of transformed Atlantic water (TAW) within the fjord, spatial variations of foraminiferal tests, their test size variations and stable isotopic composition (δ13C and δ18O) in the surface sediments were studied. Total organic carbon and textural analyses were also carried out. The dominant benthic foraminifera included Nonionellina labradorica, Elphidium excavatum, Cassidulina reniforme, Quinqueloculina stalkeri and Islandiella islandica. Nonionellina labradorica was the predominant species in the outer fjord, whereas Elphidium excavatum and Cassidulina reniforme were dominant in the inner fjord. Total organic carbon and the test size of Nonionellina labradorica within the fjord were highly correlated (r2?=?0.97) and both showed a decreasing trend towards the inner fjord. Based on the distribution and abundance of Nonionellina labradorica as well as temperature profiles, we suggest that there was little or no major change in the lateral advection of TAW within the fjord in the immediate past.     

The effects of TDI on mice bone marrow cells

Objective： To test the effects of TDI on mice bone marrow cells. Methods： The effects of TDI were studied by laser scanning confocal microtechnique to investigate the form changing of the mice bone marrow cell and genotoxicity test-chromosomal aberration test and sister chromatic exchange （sce） test. Results： The 1/16 LC50 and 1/8 LC50 dosage of TDI had no significant effect on the fluorescence pixels of RNA/DNA by laser scanning confocal microtechnique to investigate the chromosoma laberration rate and the frequencies of sister chromatic exchange of the mice （P〉0.05）. But both 1/4 LC50 and 1/2 LC50 dosage had significant effect on the fluorescence pixels of RNA/DNA by laser scanning confocal microtechnique to investigate the chromosoma laberration rate and the frequencies of sister chromatic exchange of the mice （P〈0.01）. Conclusions： TDI has the genetic toxicity.     

Runoff Variation Law and Its Response to Climate Change in the Headstream Area of the Keriya River Basin,Xinjiang

Based on the runoff and meteorological data of Langan(兰干) Hydrological Station from 1957 to 2009 in Keriya(克里雅) River,the periodicities,abrupt changes,and trends of climate factors and runoff were investigated by wavelet analysis and nonparametric test;then,the future change of the annual runoff was predicted by a periodic trend superposition model.In succession,the influencing volumes of climate change on the annual runoff were separated from the observation values of the an-nual runoff in Keriya River.The...     

Influence of plant on the extractability of estrogen in the rhizospheric soil

Livestock wastes applied to agricultural land are potential sources of steroidal hormones （estradiol （E2）, estrone （E1）, and estriol （E3）） that can adversely affect the aquatic ecosystem as endocrine disruptors. But the effects of plants on the fate of estrogen in the environment are not clearly known. In the present report, the behavior of E1, E2 and E3 added to the rhizospheric soil in various concentrations and its effect on plant growth were examined by estrogen batch sorption test, plant pot test and estrogen extraction test. Trifolium repens was grown on the soil spiked with E2 or a mixture of E1, E2 and E3. Pots without plant were prepared as controls. All pots were watered in 50 ml dose almost every day, and the rhizosheric soil and plant body were collected 7, 19, 26, 33 days after planting. The soil was sequentially extracted with Milli-Q water, and methanol / 1M acetic acid solvent followed by methanol wash at the solid to liquid ratio of 1 ： 4 （g/mL）. Extracts were analyzed for El, E2 and E3 using a Shimadzu GCMS-QP5050. Plant dry weight （4 hours, 105 ℃） was measured as an indicator of plant growth. In batch sorption tests, E1 and E2 concentrations in the liquid phase significantly decreased within 24 hours after the addition of estrogen. The sum of methanol / 1M acetic acid extractable E 1 and E2 in the soil decreased to half of the initial added amount within 7 days. Reduction in total estrogenic activity of the soil extracts （estimated as 0.01CE1＋CE2＋0.1CE3 where CE1, CE2 and CE3 are respective El, E2 and E3 concentrations per unit soil weight） continued for 1 month due to slow oxidation of E2 to E1. Desorption of E2 from soil during the pot experiment was higher than expected from the sorption experiment.     

A Simulated Test of Algal Influence of Formation and Deposition of Phosphates

This paper deals with a simulated test of biogenic mineralization made with a blue-green alga species,Spirulina platensix. The data in the experiment were recorded by a computerized surveying system. The influ-ence of algae on the accumulation of phosphorus by changing their microenvironment to promote the forma-tion and deposition of phosphate was studied. The results show that the pH value of cultural liquor rose up to 10 and the redox potential (Eh) may dropby 100-200 mV during the algal logarithmic growth stage, and the cultrual liquor was changed into a mediumwith a weakly reducing condition. At the end of the logarithmic growth stage white deposits of Na_2Ca(CO_3)_2·5H_2O and Ca_2Mg (PO_4)_2·2H_2O were formed on the floor of cultural containers. The test presented a wduableevidence for the theory of biogenic mineralization.     

A Study of Sedimentary Environment and Reservoir Quality of the Carboniferous Donghe Sandstonein the Tarim Basin

Very thick, fine-grained quartzose sandstone of the Lower Carboniferous (called the Donghe sandstone) was discovered in Donghe-1 well in the Tarim basin. Highly-productive commercial oil and gas flows were obtained when a well completion test was conducted. This important discovery proved that the quartzose sandstone is a prospecting target with good prospects. After that, other two paying oil and gas flows were found in the Lower Carboniferous in the Tazhong-4 and Tazhong-10 structures (Tazhong means central Tarim), equivalent to the Donghe sandstone. The Tazhong-4 structural oil field is the biggest oil field ever discovered. Therefore it is of guiding importance in oil and gas exploration to deepen the study of sedimentary and reservoir features and the sedimentary environment of the Donghe sandstone and to build a sedimentary model in order to understand the reservoir distribution pattern.     

Delineation of Integrated Anomaly with Generative Adversarial Networks and Deep Neural Networks in the Zhaojikou Pb-Zn Ore District,Southeast China

Geochemical maps are of great value in mineral exploration. Integrated geochemical anomaly maps provide comprehensive information about mapping assemblages of element concentrations to possible types of mineralization/ore, but vary depending on expert’s knowledge and experience. This paper aims to test the capability of deep neural networks to delineate integrated anomaly based on a case study of the Zhaojikou Pb-Zn deposit, Southeast China. Three hundred fifty two samples were collected, and ea...     

The solution of the double-sphere model and experimental research of the longterm shear strength of frozen sand based on spherical template indenter test北大核心CSCD

The distribution of frozen soil in our country is very broad, and the area of permafrost alone accounts for 22. 4% of the total land area. As a special kind of soil, frozen soil has many properties that thawing soil does not have due to the influence of ice cement in the soil. Among the many properties of frozen soil, the deformation and strength of frozen soil are the basic problems affecting engineering construction in frozen soil areas. The spherical template indenter test is widely used in the test of the mechanical properties of frozen soil because of its simple test process and relatively accurate test results. Compared with the conventional triaxial test or direct shear test, the test process of the spherical template indenter test is simple and easy to implement, the test period is short, and the sample preparation requirements are low. The advantage of effective cohesion is more significant. Therefore, based on the spherical template indenter test of the frozen soil, this paper estimates the strength and mechanical index of the soil through the indentation depth of the spherical template indenter test, and establishes the relationship between the force of the sample and the indentation depth of the indenter test. The specific test method is as follows:take the water-saturated frozen sandy soil made of different particle size groups(the moisture content of the sample is affected by the particle size in the saturated state)as the research object, study the variation law of the depth of the frozen soil sample pressed into the soil by the spherical indenter with time under the conditions of different fixed loads. By comparing and referring to the frozen sands of each particle size group, the long-term equivalent cohesion of the frozen sands of different particle size groups is summarized. The change law of force(long-term shear strength)with time, and the research method of elastic mechanics to solve space problems, summed up the mutual conversion between the depth St of spherical template indenters pressed into frozen sand samples under different fixed load test conditions relation. The research results show that the long-term shear strength of frozen sand based on the spherical mold test is positively correlated with its particle size. At the same time, since the ice content of frozen soil samples is proportional to its particle size, the long-term shear strength of frozen sand is also proportional to the test. The ice content of the sample increases year-on-year;the long-term shear strength of the frozen sand is related to the maximum contact pressure on the contact surface between the frozen soil and the indenter during the test, which can be expressed as Ct = γq0. The size of the relationship coefficient γ is inversely proportional to the diameter of the spherical indenter. In this paper, the spherical indenter is selected as 22 mm, and γ=3. 82×10-3. By establishing the relationship between the maximum contact pressure q0 and the long-term shear strength Ct When the maximum contact pressure q0 is the same under different fixed loads, the long-term shear strength Ct is also the same. According to this, the depth curve and the freezing depth of the frozen sand pressed into the soil by the spherical indenter over time under different fixed loads can be converted. Long-term shear strength curve of frozen sandy soil with time. It has been verified by experiments that the conversion curve of the depth of the indenter pressed into the soil with time under a fixed load of 7. 0 kg is highly consistent with the measured curve of the depth of the indenter pressed into the soil with time under a fixed load of 5. 1 kg and 7. 0 kg. © 2022 Nanjing Forestry University. All rights reserved.     

助磨剂的试验研究

在磨矿中加入助磨剂是有效提高磨矿效率的一个重要途径，但在我国的研究还很少。对吉林某金矿的磨矿进行了助磨剂的试验研究，试验表明：在选定的条件下，选用二氧化锰、乙醇作为助磨剂可以使磨矿时间由120min缩短到90min左右，磨矿效率提高20%左右，而且环境污染小。本试验对其它矿山的磨矿作业也有很大的参考价值。     

基于DIC技术的3D打印节理试件破裂机制研究

为了准确表征不同角度预制节理岩石在单轴压缩下的变形破坏模式,基于3D打印技术制作了节理模型用于模拟岩体中的结构面,通过水泥砂浆的浇筑得到含不同角度预制节理的岩石试件并进行单轴压缩试验,同时采用数字图像相关技术（DIC）观测、分析试验过程中试件裂纹产生、扩展以及贯通过程。结果表明：随着预制节理从0°增加到90°,试件强度与峰值应变均呈现先降低后升高的变化趋势,0°和45°试件弹性模量相对于完整试件有所降低。基于DIC检测结果,0°、30°、45°及60°试件裂纹皆从预制节理尖端部位起裂,各角度试件的起裂应力与试件强度变化规律一致。各角度试样起裂时在剪应力控制下以剪切翼型裂纹形式起裂,0°与45°试件裂纹在扩展过程由剪切发展为张拉型裂纹,30°和60°试件以剪切裂纹形式贯穿始终,90°试件从底部起裂并最终表现为张拉破坏。研究还发现,下翼起裂角θ2和上翼起裂角θ1之间存在明显的线性正相关关系,关系式为θ2 =0.828 6θ1 +12.185,且起裂应力大小变化与峰值应力变化一致,皆随节理角度的增加先减小后增大。     

矿物分散体系的触变性试验研究

目前尚没有国家标准来统一和规范触变性的测试方法,而轻工标准QB/T 1545—1992仍是应用于非金属矿物触变性测试的较为适用的方法之一,但该规范中的方法介绍较为简单,对触变性测试的影响因素(如电解质的添加)未有详细叙述和研究,实际指导性不强。本文依据QB/T 1545—1992,以膨润土和皂石为矿物样品,研究触变性测试方法及其影响因素,重点对电解质最佳用量和陈化时间进行条件试验。结果表明:添加电解质对触变性影响很大,不同矿种及同种矿物的样品在触变性试验中所需的电解质最佳添加量是不同的,测试具体矿物的触变性时,需先对电解质最佳添加量进行条件试验。样品悬浮物的陈化时间对其触变性的测试结果有很大影响。在测试触变性的过程中,应严格按照轻工标准QB/T 1545—1992规定的陈化时间10~12 h,以保证方法精密度要求;若陈化时间过长,其触变性明显增大,触变性已无法计算。本文通过对触变性测试方法中电解质用量和陈化时间两个重要影响因素的研究,可为现有触变性测试方法的改进提供一定的依据。     

压力水作用下硬石膏岩膨胀性研究

针对隧道工程中硬石膏围岩在压力水作用下的膨胀现象,设计加工了多功能膨胀仪。使用该仪器及MTS815岩石力学测试系统,对不同水压条件下硬石膏岩的轴向膨胀应变及侧向膨胀应力进行了测试,对压力水作用后硬石膏岩的含水状态及力学特性进行了测试。结果表明：水压越大,硬石膏岩的最大轴向膨胀应变及最大侧向膨胀应力越大,膨胀起始时间越短;随水压的增大,硬石膏岩的吸水率增大,结晶水率逐渐增大并趋于吸水率,而自由水率逐渐减小并趋于0;硬石膏岩的弹性模量和峰值强度随水压的增大而增大。这些说明水压能影响其含水状态,增强硬石膏岩的膨胀性,促进其膨胀的激活,提高其力学性能。基于试验结果,建立了压力水作用下的硬石膏岩吸水状态方程,并改进了湿度场理论体系中的膨胀本构模型。     

岩溶地下河浊度来源及对示踪试验影响的定量分析

定量示踪技术是分析岩溶含水层水力特征和岩溶水系统结构的重要手段,地下河浊度是制约定量示踪试验精确性的关键因素。针对西南典型岩溶地下河,以三次不同水动力条件下示踪试验为研究对象,通过对比分析浊度、流量及示踪剂浓度变化探讨浊度来源及其对示踪剂和管道参数的影响。试验过程中,确定存在上、下临界流量使水流从层流过渡为紊流状态,浊度主要来源从管道内部再悬浮颗粒过渡为外源悬浮物,计算上、下临界流量分别为0.7 m~3/s和0.4 m~3/s。通过浊度与示踪剂的相关关系研究浊度对示踪剂的影响,结果表明当浊度大于25时,浊度与示踪剂浓度呈负相关关系,且浊度越大,对示踪剂的影响越大。最后通过对比确定,第一次示踪试验浊度影响较小,并估算了岩溶管道参数,为进一步水资源评价提供基础。     

考虑渗流效应的冲流带泥沙起动机理研究

为揭示内部渗流对海岸冲流带泥沙起动的影响,系统地开展了斜坡海床冲流特性与泥沙起动机理研究。通过室内水槽开展了孤立波在可渗透和不可渗透斜坡海床上的冲流试验,测试了冲流过程中波高、波速等变化规律;建立了渗透海床冲流数值模型并通过试验结果进行验证;深入分析了床面渗流对其波浪流场动态特征以及床面泥沙起动的影响机理。研究表明,床面渗流作用加剧波浪的不对称性,在波浪上冲过程中因床面强入渗作用而增大了床面切应力;回流过程因入渗所造成流量损失而导致床面切应力减小。床面渗流引起床面颗粒有效重度和切应力变化而导致泥沙希尔兹数大大增加,加剧了泥沙起动现象,且床面切应力改变是引起泥沙希尔兹数变化的主要因素。     

大气压力对煤样解吸气含量测试结果的影响

以自然解吸样品为对象,研究大气压力对煤样解吸气含量测试结果的影响。结果表明:当样品从大气压力较低的采样地点返回大气压力较高的实验室后,每24 h的解吸气含量测试结果明显减小,减小的幅度明显大于采样地点每24 h减小的幅度;对于开始7 d解吸气含量测试结果为零或者较小、按照标准可以结束测试的样品,建议将测试时间延长在3周左右,若按照标准仍旧可以结束测试时,再停止实验;如果样品在采样地点进行解吸实验直到结束,总解吸气含量测试结果将大于实验室。      

单排抗滑桩随机有限杆单元法计算的分析与研究

文章对桩前土体需要开挖情形下的随机有限杆单元法给出了新的详细的计算公式。由于滑坡和稳定体常为碎石土和风化的软岩,不适宜用静力触探研究相关范围（土性的自相关性）,因此本文用旁压试验m值对相关范围进行研究和计算。根据所作的大量抗滑桩并参照已有的研究成果（如Meyerhof的研究成果）,建议抗滑桩的可靠度与工程结构的可靠度取值同（即一级结构[β]=3.7、二级结构[β]=3.2、三级结构[β]=2.7）。这样处理,钢筋混凝土结构的许多成果均可移植到钢筋混凝土抗滑桩中。侧向地基系数Ch（p=b1mxy=b1Chy）为与土性及埋深有关的量,本文给出了用旁压试验推求m值的两种计算公式。     

荧光示踪剂的干扰实验研究

通过在室内无光照条件下开展干扰实验,探究了荧光素钠、罗丹明和荧光增白剂三种示踪剂之间的干扰规律,并应用于野外地下水二元示踪试验实例,说明了校正荧光示踪仪检测浓度(ΔC)的方法。结果表明:（1）在实验室条件下,荧光素钠的抗干扰性最强,罗丹明次之,荧光增白剂易受到干扰产生检测浓度增大的假象,这种假象服从线性变化规律;（2）当使用罗丹明作为示踪剂时,ΔC钠=0.052C罗、ΔC白=0.012C罗;当使用荧光素钠时,ΔC罗=0.507C钠、ΔC白=0.323C钠。在野外开展二元示踪试验时,建议尽量选用相互之间干扰较小的罗丹明和荧光增白剂进行组合投放,或利用本实验得到的不同示踪剂之间的干扰规律对荧光示踪仪的检测浓度进行校正。      

冻融条件下非饱和路基土的强度及微观特性研究

为探究非饱和路基粉质黏土在冻融条件下的强度及微观特性的影响,对路基非饱和粉质黏土进行了冻融循环试验、非饱和土直剪试验、氮吸附试验,结果表明：非饱和土强度随冻融循环的增加呈先减小后趋于稳定的趋势,冻结负温为-10℃黏聚力降低最明显,通过BET法求得试样经历不同外部条件影响后的比表面积值,根据氮吸附试验的等温线计算出非饱和路基土的分形维数,试验试样的比表面积与分形维数都随冻融循环次数的增加先增大后减小,冻融循环3次时达到最大值,随冻结负温的降低而降低。从微观的角度解释了非饱和路基粉质黏土经多次冻融循环后,基质吸力对非饱和土的黏聚力影响的原因。