Postglacial lake shoreline surveys and lacustrine paleobiotic records in northern Bruce and Grey counties,Ontario, Canada

Northern Grey and Bruce counties are situated centrally in the Lake Huron basin of the Great Lakes area of North America and are similarly central to the area of glacial Lake Algonquin, the largest glacial lake of the Great Lakes area. Ten survey traverses at sites in northern Grey and Bruce counties have documented the continuation of Lake Algonquin and Nipissing phase shorelines onto the Bruce Peninsula from previous work to the east. The Algonquin shoreline near 240 m ASL (above sea level) rises northward above land high enough to record it near Lion's Head. The Nipissing shoreline at 191 m ASL defines a shallow strait across the Bruce Peninsula near Ferndale, which was flooded temporarily at the maximum of the Nipissing transgression, separating northern Bruce Peninsula from the mainland. Uplift and Port Huron outlet downcutting later rejoined the island to the mainland as it is today. Raised beaches define Algonquin and Nipissing regressions by uplift using the Port Huron outlet. Paleobiotic records in a sand dune at Oliphant (molluscs), a Nipissing shorebluff along Sucker Creek (molluscs) and several sites in the former Nipissing shallow water strait near Ferndale (molluscs, ostracodes, plant macrofossils), provide paleoenvironmental data and supplement prior pollen studies at Lake Charles, Slough of Despond, and Hope Bay. Lake Algonquin deep water rhythmite clays are barren of fossils, whereas Nipissing shallow water silts are fossiliferous.     

Determination,content analysis and removal efficiency of fining agents on ochratoxin A in Chinese wines

A simple and convenient HPLC-FD detection method for ochratoxin A (OTA) with a high detection limit and a short run time has been developed. OTA has been found in most samples of Chinese market wine, including domestic and imported wines, but the content was not very high. Only a few wines showed an OTA content that exceeded the EC and OIV limits, indicating that most Chinese market wines were safe. The OTA intake for Chinese from wine was 0.017 ng/kg (bw) per day, which was lower than the SCF and JECFA limits and also lower than in many other countries. This was mainly due to the low per capita wine consumption in China, but it is still necessary for the Chinese government and wine makers to monitor OTA levels in wine and to establish relevant regulations. An egg white treatment (0.20 mg/mL, 48 h) was the best removal method for OTA.     

冰碛土的应力-应变-强度特性的研究

本文针对四川某一电站土石坝工程的心墙料——冰碛土进行了一系列的试验研究。研究表明:随着围压力的升高,冰碛土的强度降低,强度包线为折线型式;平面应变的试验强度高于常规三轴的试验强度,文中提出了二者的转化关系式。     

醋酸工业生产方法及其深加工

本文介绍了各种醋酸生产方法和发展趋势以及有关醋酸深加工途径和应用等问题。     

微型法制备和提纯乙酰苯胺

有机实验教材中,常采用苯胺和冰乙酸加热回流、分馏分水法制备乙酰苯胺,并用热过滤和重结晶法将其提纯。该法在具体实践中,暴露出操作复杂、时间长,产率低等缺点。因此从实验微型化入手,选取合适的酰化试剂,在不加热的情况下,制备和提纯乙酰苯胺。并解决了常温过滤过程中的堵塞、污染问题,减少了副产物的产生。     

Erosion of glacial till from the St. Clair River (Great Lakes basin)

Variations in water level observed in Lakes Michigan and Huron during the last few decades have motivated a comprehensive study involving climatic, hydrologic and hydraulic factors organized by International Joint Commission of the Great Lakes. It has been submitted, among other possible causes, that changes in conveyance in the St. Clair River could be contributing to the lowering of the upper Great Lakes water level. Sediment transport processes, in particular bed scour and erosion, can affect significantly a river's conveyance, thus creating the need to assess the erodibility properties of the river bed. To this end, laboratory tests were performed in order to obtain the value of the critical shear stress needed to erode the cohesive fraction of the bed sediment material, known as glacial till, from the St. Clair River. Different flows with increasing velocities were run up to the point where initial sediment erosion could be observed. Through detailed near-bed velocity measurements using a laser Doppler velocimetry (LDV) system, a value of 4.2 N/m² was obtained as the critical shear stress for the erosion of glacial till. A threshold for the critical shear stress for erosion of similar cohesive sediments was also found and expressed in dimensionless form. These results could be used in combination with mathematical models to estimate the risk of scour and erosion at locations where the glacial till is exposed to both strong currents and flow forces induced by the large navigation vessels commonly observed along the course of the St. Clair River.     

Northernmost (?) Glacial Lake Algonquin Series Shorelines,Sudbury Basin,Ontario

Shorelines of Lake Algonquin, the largest of the glacial lakes of the Great Lakes area, are well known in southern Ontario, but are sporadic and difficult to trace northward onto the Precambrian shield. Improved knowledge of the extent and uplift pattern for Algonquin shorelines is needed to support geophysical models of isostatic response, interpretation of glacial and glacial lake history, and the search by archeologists for evidence of Paleoindian activity, shown to be localized along its shoreline. The Sudbury basin is one of the few areas of mapping of Quaternary geology on the Canadian shield that provides a record of Algonquin lake phases. Meltwaters from the northward-receding ice front formed a series of deltas southward into the Sudbury basin in central Ontario around the time the Cartier I moraine was deposited. Instrumental surveys of deltas, bars, and shorebluffs carried out in the northern Sudbury basin delineate several discrete water planes. Correlation with previously surveyed and correlated shorelines on Manitoulin Island, southwest of Sudbury, indicates the presence of an upper Algonquin shoreline and features correlated to the Cedar Point, Payette, Sheguiandah, and Korah levels. Features southwest of the Sudbury basin at Nairn correlate with Korah and post-Korah water levels. Land between Nairn and Sudbury is too elevated to have been reached by the later Nipissing transgression. Similar shoreline sequences have been surveyed near North Bay, with results supporting the findings of this study.     

A story about distributions of dimensions and locations of boulders

The topic concerns the density of occurrence of boulders and the joint distribution of the primary boulder dimensions in the till deposits of the Great Belt region in Denmark. The investigation was made in 1987–1988 on the initiative of A/S Storebæltsforbindelsen in order to prepare the tendering for making a bored tunnel through the till deposit. Geographical universality was discovered through the statistical analysis of observations of boulder coordinates and dimension measures from widespread cliff beach locations. One conclusion is that the joint size distribution up to some degree of modeling approximation has a surprisingly simple structure. In particular, the maximal dimension has an exponential distribution while the ratios between maximal and intermediate dimension and between the intermediate dimension and the smallest dimension are independent and identically distributed according to a beta-distribution. Moreover, these ratios are independent of the maximal dimension.The random point field structure of the boulder coordinates as isolated points or as clusters of points makes Poisson fields reasonable modeling candidates for the fields of both single points and cluster points. The cluster size distributions are well modeled by a Markov chain type of model. Different details of the data and their statistical analysis support several modeling conjectures concerning the glacial history of boulder deposition.In a companion paper, it is described how the results of this beach boulder investigation are used for interpretation of the results from seismic scanning of the till deposits along the planned tunnel line, and for prediction of the density of boulders of maximal dimension above any specified length.     

化学驱油中浊度法测定HPAM浓度的准确性

大庆油田聚合物驱和三元复合驱中普遍采用冰醋酸－次氯酸钠浊度法测定ＨＰＡＭ浓度,由于应用条件复杂多变,测定结果的准确性不好。实验考察了ＨＰＡＭ的水解度,分子量,水质碱、表面活性剂ＯＲＳ－４１及ＨＰＡＭ生产厂家对测定结果的影响 发现除ＯＲＳ－４１外,其余因素的影响都很大,这使实际生产中很难制作出合乎该法要求的标准工作曲线。