Thermal structure of hot events and their possible role in maintaining the warm isothermal layer in the Western Pacific warm pool     

Wirasatriya  Anindya  Kawamura  Hiroshi  Helmi  Muhammad  Sugianto  Denny Nugroho  Shimada  Teruhisa  Hosoda  Kohtaro  Handoyo  Gentur  Putra  Yoppik Disma Girindra  Koch  Magaly 《Ocean Dynamics》2020,70(6):771-786

Ocean Dynamics - The short-lived events of high SST are called hot events (HEs) and can only be generated under the conditions of large daily heat gain due to strong solar radiation and weak wind....  相似文献   

Green and Eco‐Friendly Removal of Mycotoxins with Organo‐Bentonites; Isothermal,Kinetic, and Thermodynamic Studies     

Muhammad Saeed  Komal Farooq  Muhammad Nafees  Muhammad Arshad  Mohammad Salim Akhter  Amir Waseem 《洁净——土壤、空气、水》2020,48(9)

In the current study the application of organo‐modified bentonite for the adsorption of mycotoxins (aflatoxin B1, citrinin, patulin, and zearalenone) is presented. The modification of clays is carried out using benzyl‐tri‐n‐butyl ammonium bromide (BTB), benzethonium chloride (BTC), and dioctyl sodium sulfosuccinate (DSS). Various experimental parameters such as pH, time, adsorbent dose, and mycotoxins concentration are thoroughly studied. The modified clays (B‐BTB, B‐BTC and B‐DSS) are characterized by X‐ray fluorescence, X‐ray diffraction, and Fourier transform infrared spectroscopy. The results depicted the high detoxification efficiency (≈99%) of modified clays for the removal of mycotoxins under optimized conditions (pH 5, time: 30 min, adsorbent amount: 50 mg). The adsorption capacities of modified clays are found in the order of: B‐BTC (AFB1: 18.02, CIT: 18.35, PAT: 18.21, ZEA: 18.09 mg g^?1) > B‐BTB (AFB1: 17.7, CIT: 18.11, PAT: 17.95, ZEA: 17.90 mg g^?1) > B‐DSS (AFB1: 17.5, CIT: 18.02, PAT: 17.86, ZEA: 17.80 mg g^?1). The obtained results fitted well with thermodynamic, isothermal (Langmuir) and pseudo‐second order kinetics. Low cost organo‐modified bentonite shows the promise in mitigating mycotoxin contamination, which could improve food safety and reduce environmental contamination.  相似文献   

高密度电法电性结构揭示天山天池堆积坝体厚度及其阻渗稳水功能分析     

尚彦军  金维浚  伊学涛  姜东廷  HASAN Muhammad 《现代地质》2023,37(1):31-39

天山天池北堆积坝体结构受其成因和演化控制,影响其含水和渗流特性。对该坝体稳定至关重要的下伏基岩埋深、坝体结构阻渗水结构特征等需现场探测并给出科学判断。在地质调查基础上采用高密度电法对天池堆积坝体结构进行探测,首次获得深达下伏基岩的堆积坝体纵向和横向电性剖面。结合光释光测年、水化学成分对比、水量平衡计算等手段,分析坝体堆积物形成时代以及坝体水文地质结构特征。结果显示：天池坝堆积体厚度大于100 m并可分为3层,上部浅表层滑坡形成的巨大块石层厚30～40 m且基本不含水,其下松散含水层厚度为30～50 m;下部为较低电阻率弱透水的冰碛物,主要分布在坝体下游和东端;底部为高电阻率不透水的石炭系火山岩。坝体中间部位地下水集中下渗补给了西小天池。同时靠坝体东侧发育排泄通道,呈现多处溢水点,控制了飞龙涧左岸下降泉季节性发育,同河谷冲刷作用一起影响并导致下游左岸冰碛物中发育4处滑坡体。电法剖面揭示出与坝体轴向近平行的2条隐伏断层,其中堆积坝高堤处气象台所在山丘上游一侧发育一条近东西走向并倾向上游的断层F1,构成地下水阻隔带而使天池堆积坝上游潜水水位呈现一定雍高,同坝体下伏基岩和弱透水冰碛物联合组成的...  相似文献   

Trace Metals Accumulation and Antioxidants Profiling in Two Maize Genotypes Against Sewage and Textile Wastewater Treatment     

Zoya Zafar  Javaid Akhtar  Muhammad Amjad  Muhammad Anwar‐ul‐Haq  Zulfiqar Ahmed Saqib 《洁净——土壤、空气、水》2019,47(7)

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Response of infilled frames using pseudo-dynamic experimentation     

Khalid M. Mosalam  Richard N. White  Gustavo Ayala 《地震工程与结构动力学》1998,27(6):589-608

An accurate and practical testing technique to study seismic performance of multi-storey infilled frames is formulated. This technique is based on the pseudo-dynamic method which can provide an acceptable approximation of the dynamic performance of structures under the influence of earthquake excitation. The pseudo-dynamic experimental technique is outlined and applied for testing a two-bay, two-storey gravity load designed steel frame infilled with unreinforced concrete block masonry walls. From the discussion of the results, the dynamic performance of the tested structure is assessed. © 1998 John Wiley & Sons, Ltd.  相似文献   

Modeling radon time series on the North Anatolian Fault Zone,Turkiye: Fourier transforms and Monte Carlo simulations     

Muhammad  Ahmad  Külahcı  Fatih  Akram  Pishtiwan 《Natural Hazards》2020,104(1):979-996

Natural Hazards - Time series studies depend mostly on stochastic models for radon seasonal, annual or temporal variability explanations. Others solve radon transport steady state equation...  相似文献   

厦门西港表层沉积物中多环芳烃(PAHs)的含量分布特征及其污染来源   总被引：10，自引：0，他引：10  

张祖麟  王新红  哈里德  周俊良  陈伟琪  徐立  洪华生 《海洋通报》2001,20(1):35-39

利用GC－FID对厦门西港1998年7月采得8个站位表层沉积物中的16种多环芳烃（PAHs)进行了分析。结果显示，16种多环芳烃总量分布范围为247－480ng/g，平均为367ng/g。与1993年的厦门港的分析结果相比较，多环芳烃的污染程度降低；同世界其他港口相比较，其污染程度相对较低。同时，分析了厦门港PAHs污染的分布特征及其可能的污染来源，表明其主要是由于人类的油污染及燃料燃烧引起的。  相似文献   

Organic compound tracers of fine soil and sand particles during summer in the metropolitan area of Riyadh,Saudi Arabia     

Khalid Al-Mutlaq  Ahmed I. Rushdi  Bernd R. T. Simoneit 《Environmental Geology》2007,52(3):559-571

Soil and sand fine particles, which may be resuspended as fine dust in the atmosphere, contain a variety of anthropogenic and natural organic components. Samples of fine soil and sand particles (sieved to <125 μM) were collected from the Riyadh area in the summer of 2003 and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The derivatized total extracts were analyzed by gas chromatography–mass spectrometry in order to characterize the composition and sources of the organic components. Both anthropogenic and natural biogenic inputs were the major sources of the organic compounds in these extracts. Discarded plastics and vehicular emission products were the major anthropogenic sources in the fine particles from populated areas of the city. Their tracers were plasticizers, UCM, n-alkanes, hopanes and traces of steranes. Vegetation was the major natural source of organic compounds in samples from outside Riyadh and included n-alkanols, n-alkanoic acids, n-alkanes, methyl alkanoates, sterols and triterpenoids. Carbohydrates had high concentrations (42–54%) in all samples and indicate sources from decomposition of cellulose and/or the presence of viable microbiota such as bacteria and fungi. The results were also compared with the data obtained in winter 2002 and showed that anthropogenic inputs were higher in summer than in winter, whereas the opposite trend was observed for natural inputs.  相似文献   

A Conceptual Framework for Enhancing the Utility of Rainfall Hazard Forecasts for Agriculture in Marginal Environments   总被引：1，自引：0，他引：1  

Muhammad?T.?UsmanEmail author  Emma?Archer  Peter?Johnston  Mark?Tadross 《Natural Hazards》2005,34(1):111-129

Semi-arid and dry sub-humid areas (especially in the tropics) are characterized by high inter-annual and intra-seasonal rainfall variability. Agriculture, which employs the bulk of the rapidly increasing populations, is largely rain-fed, low-input based and highly resource dependent. Recent spates of drought have, therefore, exacerbated the now-too-familiar specter of famine and starvation in these areas with glaring examples being the recurring episodes in sub-Saharan Africa since the great Sahel drought of 1969–1973. A great need for accurate and timely hazard forecast products in aid of agriculture thus exists.Several schemes are currently employed by various agencies around the globe in this direction. There does remain, however, a gap between product provision and user expectations. This paper examines this gap suggesting a five-point framework within which it can be addressed as an action agenda for the climate science community. The paper posits that changes are possible to existing methodologies (related to three of these points), which, within the context of current science, can greatly enhance the utility of forecast products for agriculture in marginal areas. The remaining two points have, however, been identified as requiring additional applied research and necessary pointers for addressing these issues are provided. First is the need for appropriate impact-related indicators for intra-seasonal and interannual rainfall variability that are easy to compute, amenable to forecasting and follow closely the experiences of farmers in marginal areas. The second is a consideration of appropriate forecast information formatting and communication medium that guarantee effective feedback between forecast producers and users. Specific examples of the status quo and of work currently underway are cited from southern Africa – a region currently attracting international attention as a result of recent droughts and the threat of famine.  相似文献   

Detrital zircon U–Pb geochronology of a Cenozoic foreland basin in Northeast India: Implications for zircon provenance during the collision of the Indian and Asian plates     

Upendra Baral  Ding Lin  Tapos Kumar Goswami  Mondip Sarma  Muhammad Qasim  Devojit Bezbaruah 《地学学报》2019,31(1):18-27

Geochronology is useful for understanding provenance, and while it has been applied to the central and western Himalaya, very little data are available in the eastern Himalaya. This study presents detrital zircon U–Pb ages from the late Palaeocene–Eocene Yinkiong Group in NE India. The samples are from the late Palaeocene to early Eocene Lower Yinkiong Formation, and the Upper Yinkiong Formation deposited during the early to mid‐Eocene within the Himalayan foreland basin. The U–Pb ages of the detrital zircon within the Lower Yinkiong Formation are older than late Palaeozoic, with a cratonic and early Himalayan Thrust Belt affinity, whereas the Cenozoic grains in the Upper Yinkiong Formation indicate a Himalayan Thrust Belt source and possibly a granitic body within the Asian plate. The shift of the sources and the changes in the foreland basin system strongly suggest that the India–Asia collision in the Eastern Himalaya began before or immediately after the deposition of the Upper Yinkiong Formation, i.e., within the early Eocene (c. 56 to 50 Ma).  相似文献