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Developing a chloramine decay index to understand nitrification:A case study of two chloraminated drinking water distribution systems

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Journal of Environmental Sciences 2017年第7期29卷 170-179页

The management of chloramine decay and the prevention of nitrification are some of the critical issues faced by water utilities that use chloramine as a *** this study,potential association between high performance size exclusion chromatography（HPSEC）data obtained with multiple wavelength Ultraviolet（UV） detection from two drinking water distribution systems in Australia and nitrification occurrence was *** increase in the absorbance signal of HPSEC profiles with UV detection at λ = 230 nm between apparent molecular weights of 200 to 1000 Da was observed at sampling sites that experienced rapid chloramine decay and nitrification while its absorbance signal at λ =254 nm decreased.A chloramine decay index（C.D.I） defined as the ratio of area beneath the HPSEC spectra at two different wavelengths of 230 and 254 nm,was used in assessing chloramine decay *** *** of waters at locations that experienced nitrification were consistently higher than locations not experiencing nitrification.A simulated laboratory study showed that the formation of nitrite/nitrate and/or soluble microbial products and/or the release of extracellular polymeric substances（EPS） during nitrification may contribute to the *** findings suggest that C.D.I derived from HPSEC with multiple wavelength UV detection could be an informative index to track the occurrence of rapid chloramine decay and nitrification.

关键词： HPSEC Water distribution systems Nitrification Chloramine decay

Oil-bearing fluid inclusions from the Palaeoproterozoic:A review of biogeochemical results from time-capsules >2.0 Ga old

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Science China Earth Sciences 2009年第1期52卷 1-11页

作者： Simon C. GEORGE Adriana DUTKIEWICZ Herbert VOLK john RIDLEY david J. MOSSMAN Roger BUICK Department of Earth and Planetary Sciences Macquarie University School of Geosciences University of Sydney CSIRO Petroleum Department of Geosciences Colorado State University Department of Geography Mount Allison University Department of Earth and Space Sciences & Astrobiology Program University of Washington

The observation of oil inclusions trapped prior to 2.0 Ga in Palaeoproterozoic rocks and the ability to obtain detailed molecular geochemical information from them provide a robust way for understanding the early biog... 详细信息

关键词： Palaeoproterozoic fluid inclusion oil biomarker blank

A comparative study of the role of solute,potent particles and ultrasonic treatment during solidification of pure Mg,Mg-Zn and Mg-Zr alloys

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Journal of Magnesium and Alloys 2021年第3期9卷 829-839页

作者： Nagasivamuni Balasubramani Gui Wang Mark A.Easton david H.St john Matthew S.Dargusch Centre for Advanced Materials Processing and Manufacturing(AMPAM) School of Mechanical and Mining EngineeringThe University of QueenslandBrisbane 4072Australia School of Engineering RMIT UniversityCarlton3053 VICAustralia

Ultrasonic treatment(UST)applied during the solidification of pure Mg,eutectic(Mg-Zn)and peritectic(Mg-Zr)alloys was investigated in order to explore the grain refinement *** dependent grain refinement is observed in pure Mg where decreasing the superheat temperature(at which UST is applied from above the melting temperature,TM)from 100℃to 40℃produces significant refinement with a uniform grain *** presence of solute reduces the temperature dependence of the UST refinement and excellent grain refinement is obtained regardless of the superheat temperature(100℃or 40℃)and even with the use of preheated sonotrode in the Mg-6 wt.%Zn alloy.A further improvement in grain refinement is achieved when the alloy contains potent particles that introduce additional nucleation of grains in Mg-0.5 and 1.0 wt.%Zr alloys(producing an average grain size of≤100μm).At 40℃superheat,UST of Mg-Zn alloys produces excellent refinement(average grain size<200μm)with non-dendritic grains,which is normally achieved only with the addition of grain refining master alloy in the as-cast *** enhanced refinement observed in the eutectic alloy is explained through the undercooling imposed by a relatively cold sonotrode combined with high frequency vibrations and acoustic *** advantages of using a cold sonotrode,a low superheat and solute are demonstrated for achieving significant refinement during solidification of Mg alloys under UST without or with a lower addition of grain refining master alloys.

关键词： Grain refinement Mg-Zn alloy Mg-Zr alloy Ultrasonic treatment Interdependence Model Solidification

Sheep numbers required for dry matter digestibility evaluations when fed fresh perennial ryegrass or forage rape

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Animal Nutrition 2017年第1期3卷 61-66页

作者： Xuezhao Sun Linda Krijgsman Garry C.Waghorn Holly Kjestrup john Koolaard david Pacheco Grasslands Research Centre Agresearch Limited DairyNZ Limited

Research trials with fresh forages often require accurate and precise measurement of digestibility and variation in digestion between individuals, and the duration of measurement periods needs to be established to ensure reliable data are obtained. The variation is likely to be greater when freshly harvested feeds are given, such as perennial ryegrass(Lolium perenne L.) and forage rape(Brassica napus L.),because the nutrient composition changes over time and in response to weather conditions. Daily feed intake and faeces output data from a digestibility trial with these forages were used to calculate the effects of differing lengths of the measurement period and differing numbers of sheep, on the precision of digestibility, with a view towards development of a protocol. Sixteen lambs aged 8 months and weighing 33 kg at the commencement of the trial were fed either perennial ryegrass or forage rape(8/treatment group) over 2 periods with 35 d between measurements. They had been acclimatised to the diets, having grazed them for 42 d prior to 11 days of indoor measurements. The sheep numbers required for a digestibility trial with different combinations of acclimatisation and measurement period lengths were subsequently calculated for 3 levels of imposed precision upon the estimate of mean dry matter(DM) digestibility. It is recommended that if the standard error of the mean for digestibility is equal to or higher than 5 g/kg DM, and if sheep are already used to a fresh perennial ryegrass or forage rape diet,then a minimum of 6 animals are needed and 4 acclimatisation days being fed individually in metabolic crates followed by 7 days of measurement.

关键词： Sheep Digestibility Fresh forage Sample size

Microalloyed Steels for Heat Treating Applications at Higher Process Temperatures

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Journal of Iron and Steel Research International 2011年第S1期18卷 80-89页

作者： david K.Matlock john G.Speer Steven G.Jansto Marcus Stuart Advanced Steel Processing and Products Research Center Colorado School of MinesGoldenColorado USA CBMM-Reference Metals BridgevillePA CBMM Sao PauloBrasil

The potential is considered for use of microalloyed bar steels,in conjunction with thermomechanical processing,to enhance the properties of steels heat treated at higher process temperatures than have been used *** examples are highlighted:microalloyed spring steels with enhanced resistance to tempering and Nb-modified gear steels for high temperature vacuum carburizing,*** the order of 1050℃ versus 930℃ for a typical gas carburizing *** the spring steel example,the Nb+V steel results in significantly finer prior austenite grain sizes than the other steels considered,enhanced fatigue performance,and improved *** the Nb-modified carburizing steel,Nb additions up to 0.1 wt pct to a Ti-modified 8620 steel,in conjunction with thermomechanical processing to control initial precipitate distributions prior to carburizing,are shown to lead to materials with improved resistance to abnormal austenitic grain growth at the higher process *** content and heating rate to the carburizing temperature were shown to be important variables and suppression of abnormal grain growth was correlated with the development of a critical distribution of fine NbC precipitates,stable at the austenitizing temperature leading to improved fatigue performance in steels with fine and uniform grain *** for extending the results of this study to alloy design and controlled rolling in bar mills are assessed.

关键词： microalloying niobium thermomechanical processing carburizing abnormal grain growth

Repeated and random components in Oklahoma's monthly precipitation record

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International Soil and Water Conservation Research 2018年第3期6卷 261-263页

作者： Jurgen D.Garbrecht david P.Brown X.C.john Zhang USDA Agricultural Research Service Grazingland Research Laboratory7302 West Cheyenne Str.El RenoOK 73036United States

Precipitation across Oklahoma exhibits a high degree of spatial and temporal variability and creates numerous water resources management challenges. Risk-based decision making in agricultural and water resources management may find value in knowing the extent to which historical precipitation can provide guidance for inferring expectations of future monthly precipitation. A 123-year long monthly precipitation record from the central Oklahoma climate division was evaluated, in a proof-of-concept analysis, to establish whether a simple monthly precipitation decomposition into repeatable (expected) and random (unexpected) components could identify the odds of encountering repeatable or random monthly precipitation in the future. The metric for identifying precipitation kind was based on it falling within or outside of a predetermined range, defined by the relative difference between random and a percentage of repeatable precipitation. For climate conditions in central Oklahoma, the odds of future precipitation being repeatable were between 18% and 33%, depending on the month of the year. The corresponding odds of precipitation being random were 67–82%. Thus, management decisions that rely solely on historical precipitation records to anticipate future monthly precipitation have a low probability of success in central Oklahoma.

关键词： Precipitation Climate Classic decomposition Precipitation expectation Risk Water resources

How reproductive allocation and flowering probability of individuals in plant populations are affected by position in stand size hierarchy,plant size and CO_(2) regime

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Journal of Plant Ecology 2008年第4期1卷 207-215页

作者： Caroline Brophy david J.Gibson Peter M.Wayne john Connolly School of Mathematical Sciences Environmental and Ecological Modelling GroupUniversity College DublinBelfieldDublin 4Ireland Department of Plant Biology Center for EcologySouthern Illinois UniversityCarbondaleIL 62901-6509USA Harvard Medical School Osher Research Center Landmark Center Suite 22A401 Park DrBostonMA 02215USA

Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis *** also assess the effects of plant size and changing level of CO_(2) on both *** Sinapis arvensis L.,(field mustard),an annual agricultural weed,was grown in monoculture at six densities under ambient and elevated CO_(2) in a study with 84 *** aboveground biomass and reproductive biomass were *** density produced a wide range of mean plant sizes across stands and size hierarchies within ***(;40%)individuals had zero reproductive *** a novel modelling approach,we analysed the joint effects of position in stand size hierarchy,plant size and CO_(2) on RA and flowering probability of *** Findings We found a strong effect of position within the size hierarchy of individuals in a population:for an individual of a given size,greater size relative to neighbours substantially increased RA and flowering probability at a single harvest *** was no other effect of plant size on *** found a positive effect of elevated CO_(2) on RA regardless of position within the size *** observed patterns could impact doubly on the reproductive biomass(R)of small ***,because RA is not affected by size,smaller plants will have smaller R than larger plants;and second,for smaller plants lower down in a population size hierarchy,their RA and hence R will be further *** results suggest that size relative to neighbours may be independent of and more important than direct abiotic effects in determining *** studies are required to evaluate how these observed patterns generalize to other populations in non-experimental conditions.

关键词： asymmetric competition neighbour effects nonreproducing plants stand effects Sinapis arvensis

Atlantoaxial rotatory displacement in children

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World Journal of Orthopedics 2017年第11期8卷 836-845页

作者： david Spiegel Shikshya Shrestha Prakash Sitoula Norma Rendon john Dormans Division of Orthopaedic Surgery Children’s Hospital of Philadelphia Perelman School of Medicine at the University of Pennsylvania Kathmandu Model Hospital Department of Orthopedics Nobel Medical College Teaching Hospital Center for Fetal Diagnosis and Treatment Children’s Hospital of Philadelphia Department of Orthopaedic Surgery Texas Children’s Hospital

AIM To correlate the Pang and Lee class with the clinical course in a consecutive series of patients presenting with painful *** Forty-seven dynamic rotational computed tomography(CT) scans in 35 patients were classified into one of the five types defined by Pang and Li, including types Ⅰ(atlantoaxial rotatopry fixation), Ⅱ("pathologic stickiness" without crossover of C1 on C2), Ⅲ("pathologic stickiness" with crossover of C1 on C2), Ⅳ(normal or muscular torticollis), and Ⅴ(diagnostic grey zone). The Pang and Li class was then compared with the radiologist's report, which was graded abnormal, diagnosis of rotatory subluxation or fixation, or non-diagnostic. Medical records were reviewed and the clinical course was compared among the five *** We reviewed 47 CT scans in 35 patients, and the majority were performed without sedation. The average age was 7.7 years(4-14 years old) and associated conditions included minor trauma(20%), surgical procedures around the head and neck(29%), and Grisels syndrome(20%). Twenty-six percent of our studies fell within the pathologic spectrum(5% type 1 or rotatory fixation, 21% types 2 and 3 or rotatory subluxation), while 45% were classified as muscular torticollis(45%) and 28% fell within the diagnostic grey zone. Seven radiologists interpreted these studies, and their interpretation was discordant in 45% of cases. Clinical resolution occurred in 27 of 29 cases for which follow-up was available. One of two patients with fixed rotatory subluxation required a C1-C2 *** The Pang and Li classification characterizes a spectrum of abnormalities in rotation to facilitate communication, although the indications for dynamic CT scan should be further defined.

关键词： Atlanto-axial rotatory subluxation Atlantoaxial rotatory fixation Dynamic rotational computed tomography Atlanto-axial rotatory displacement

Data Strategies-Lessons and Examples from the Frontier Lines of an International Oil and Gas Company

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Acta Geologica Sinica(English Edition) 2019年第S01期93卷 28-31页

作者： david A.LEARY SUN Shaoqing john FERGUSON Leary Geological Consulting SedonaArizonaUSA 86336 ExxonMobil Exploration Company(retired) HoustonTexasUSA 77389 C&C Reservoirs 13831 Northwest FreewanSuite 450HoustonTexasUSA 77040 Geologic Data Systems 5994 South Prince StreetSuite 203LittletonColoradoUSA 80120

Data strategies and tactics used to create and promulgate robust databases across a wide organization are subject to a number of constraints and *** presentation reviews lessons learned from one company in the oil and gas industry,and illustrates how that company met and overcame challenges during the database design and implementation phases.

关键词： database strategies database challenges oil and gas