MIT's Computer Resource Lab:     

LYNA L. WIGGINS  JOSEPH FERREIRA JR. 《International journal of geographical information science》2013,27(4):299-307

Abstract

The paper describes the curriculum on geographic information systems developed in the Department of Planning at the Massachusetts Institute of Technology for those studying for the Master in City Planning degree. Particular emphasis is given to the part played by the Computer Resources Lab in serving the needs of the architecture and planning departments, the interactions between teaching and research, and those between the course and professional practice. The required courses are outlined and the wide range of recommended courses, drawn from a number of departments in the Institute, are listed- The authors emphasize the necessity of their being at the forefront of research if they are lo maintain the flow of hardware and software from contacts and donations on which their research and teaching depend.  相似文献   

Comparison of the structure and accuracy of two land change models     

Robert Gilmore Pontius JR  Jeffrey Malanson 《International journal of geographical information science》2013,27(6):745-748

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菲律宾Zambales蛇绿岩套的再研究：对其特提斯来源的启示     

Karlo L. QUEA?O  Carla B. DIMALANTA  Graciano P. YUMUL JR.  Decibel V. FAUSTINO-ESLAVA  Edanjarlo J. MARQUEZ  Noelynna T. RAMOS  Keisuke ISHIDA  Shigeyuki SUZUKI  Ricky C. SALAPARE  Michael Peter M. SANCHEZ  Juan Miguel R. GUOTANA  Rose Ann B. CONCEPCION 《地球学报》2012,33(S1):58-58

A number of geological studies have already been conducted on the Zambales Ophiolite Complex (ZOC), a north-south trending complete ophiolite sequence exposed in the western portion of Central Luzon, Philippines. Previous works recognized the ZOC as being made up of two blocks, the Acoje and the Coto, acting as an arc-back arc pair sometime during the Eocene.  相似文献   

Numerical simulation of flow around a circular cylinder close to a flat seabed at high Reynolds numbers using a k–ε model     

Muk Chen Ong  Torbjørn Utnes  Lars Erik Holmedal  Dag Myrhaug  Bjørnar Pettersen 《Coastal Engineering》2010

High Reynolds number flows around a circular cylinder close to a flat seabed have been computed using a two-dimensional standard high Reynolds number k–ε turbulence model. The effects of gap to diameter ratio, Reynolds number and flat seabed roughness for a given boundary layer thickness of the inlet flow upstream of the cylinder have been investigated. Hydrodynamic quantities and the resulting bedload transport have been predicted, and the vortex shedding mechanisms have been investigated. Predictions of hydrodynamic quantities around a cylinder located far away from the bed (so that the effect of the bed is negligible) are in satisfactory agreement with published experimental data and numerical results obtained for the flow around an isolated cylinder. Results for lower Reynolds number flows have also been computed for comparison with the high Reynolds number flow results. Overall it appears that the present approach is suitable for design purposes at high Reynolds numbers which are present near the seabed in the real ocean.  相似文献   

Anorthositic Rocks of the Duluth Complex: Examples of Rocks Formed from Plagioclase Crystal Mush     

MILLER  JAMES D.  JR; WEIBLEN  PAUL W. 《Journal of Petrology》1990,31(2):295-339

Anorthositic rocks compose 35–40% of the Middle Proterozoic(Keweenawan; 1?1 Ga) Duluth Complex—a large, compositemafic body in northeastern Minnesota that was intruded beneatha comagmatic volcanic edifice during the formation of the Midcontinentrift system. Anorthositic rocks, of which six general lithologictypes occur in one area of the complex, are common in an earlyseries of intrusions. They are characterized on a local scale(meters to kilometers) by nonstratiform distribution of rocktypes, variably oriented plagioclase lamination, and compositeintrusive relationships. Variably zoned, subhedral plagioclaseof nearly constant average An (60) makes up 82–98% ofthe anorthositic rocks. Other phases include granular to poikiliticolivine (Fo_66–38), poikilitic clinopyrox-ene (En'_73–37),subpoikilitic Fe-Ti oxides, and various late-stage and secondaryminerals. Whole-rock compositions of anorthositic rocks are modelled bymass balance to consist of three components: cumulus plagioclase(70–95 wt.%), minor cumulus olivine (0–5%), anda gabbroic postcumulus assemblage (5–27%) representinga trapped liquid. The postcumulus assemblage has textural andcompositional characteristics which are consistent with crystallizationfrom basaltic magma ranging from moderately evolved olivinetholeiite to highly evolved tholeiite (mg=60–25). Sympatheticvariations of mg in plagioclase and in mafic minerals suggestthat cumulus plagioclase, though constant in An, was in approximateequilibrium with the variety of basaltic magma compositionswhich produced the postcumulus assemblages. Standard models of mafic cumulate formation by fractional crystallizationof basaltic magmas in Duluth Complex chambers, although ableto explain the petrogenesis of younger stratiform troctoliticto gabbroic intrusions, are inadequate to account for the field,petrographic, and geochemical characteristics of the anorthositicrocks. Rather, we suggest an origin by multiple intrusions ofplagioclase crystal mushes—basaltic magmas charged withas much as 60% intratelluric plagioclase. The high concentrationsof cumulus plagioclase (70–95%) estimated to compose theanorthositic rocks may reflect expulsion of some of the transportingmagma during emplacement or early postcumulus crystallizationof only plagioclase from evolved hyperfeldspathic magma. Althoughthe evolved compositions of anorthositic rocks require significantfractionation of mafic minerals, geophysical evidence indicatesthat ultramafic rocks are, as exposure implies, rare in theDuluth Complex and implies that plagioclase crystal mushes werederived from deeper staging chambers. This is consistent withinterpretations of olivine habit and plagioclase zoning. Moreover,plagioclase could have been segregated from coprecipitatingmafic phases in such lower crustal chambers because of the buoyancyof plagioclase in basaltic magmas at high pressure. The geochemicaleffects of plagioclase suspension in basaltic magmas are consistentwith observed compositions of cumulus plagioclase in the anorthositicrocks and with the geochemical characteristics of many comagmaticbasalts. The petrogenesis of the anorthositic rocks and theoverall evolution of Keweenawan magmas can be related to thedynamics of intracontinental rift formation.  相似文献   

GRADED RHYTHMIC BEDDING IN THE CAPE EEAR FORMATION, CAROLINA COASTAL PLAIN     

S. DUNCAN HERON JR.    DONALD J. P. SWIFT  CHARLES E. DILL JR. 《Sedimentology》1968,11(1-2):39-52

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Coexisting Amphiboles     

KLEIN  CORNELIS  JR. 《Journal of Petrology》1968,9(2):281-330

Chemical analyses for the following amphibole pairs are presented:anthophyllite—tremolite (or actinolite, or hornblende),cummingtonite (or grunerite)–actinolite (or hornblende),cummingtonite (or grunerite)–anthophyllite (or gedrite),and manganoan cummingtonitemagnesioriebeckite. Nineteen analyses of such pairs are quoted from the literature,and thirty-seven additional pairs have been newly analyzed byelectron probe techniques. Quantitative microprobe determinationsof Si, Al, Fe, Mn, Mg, Ca, and Na were made on polished thin-sections,using naturally occurring, analyzed, homogeneous amphibolesas standards. The literature analyses and the electron probeanalyses for metamorphic, two-amphibole assemblages are givenfor amphiboles in physical contact, which show no textural evidenceof one amphibole being a reaction or alteration product of theother. The chemical data for some of the volcanic, two—amphiboleassemblages were obtained from occurrences that probably donot represent equilibrium pairs. The chemical data are used to determine the extent of the miscibilitygaps between the various amphibole series and the fractionationof the major elements between the two amphiboles of a pair.Anthophyllite and members of the cummingtonite-grunerite seriesgenerally have a larger Fe(total)/Mg ratio than the coexistingcalcic amphibole. The maximum CaO, Al₂O₃and Na₂O contents ofcummingtonite in metamorphic cummingtonite—hornblendepairs are 19 and 32, 02 weight per cent, respectively. Themaximum CaO, A1₂O₃, and Na₂O contents of cummingtonite in metamorphiccummingtonite-hornblende pairs are 19, 32, and 02 weightper cent, respectively. Larger CaO and Al₂O₃ values reportedin the literature were found to be too high because of admixtureof actinolite or hornblende in the analyzed separates. Smallamounts of MnO tend to concentrate preferentially in anthophylliteor cummingtonite of anthophyllite-hornblende and cummingtonite-hornblendepairs. Anthophyllite-cummingtonite pairs may show very similarFe(total)/Mg ratios and differ slightly in Al₂O₃ content only.  相似文献   

The cross sectional salt balance in a tropical estuary during a lunar tide and a discharge event   总被引：1，自引：0，他引：1  

K.R. Dyer  W.K. Gong  J.E. Ong 《Estuarine, Coastal and Shelf Science》1992,34(6)

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Chemical Petrology of Grenville Schists near Fernleigh, Ontario     

HOUNSLOW  A. W.; MOORE  J. M.  JR 《Journal of Petrology》1967,8(1):1-28

A suite of mica schists from the staurolite zone was studiedin detail. Phase rule considerations and distribution relationsindicate that chemical equilibrium was attained within the samplevolume. Iron-magnesium ratios of the silicates vary greatly,and correlate with rock ferrous-ferric ratio, as does the oxidemineral mode. Rock oxidation state varies locally, and is probablydependent on the composition of the original sediment. Distribution coefficients for Fe, Mg, and Mn among garnet, biotote,and staurolite show no vaiation attributable to temperature.Partition of Fe and Mg between staurolite and biotite is regular,but non-ideal. The staurolite structure permits only limited(15–35 percent) substitution of Mg for Fe.  相似文献   

Solvent–water extraction method for the evaluation of polycyclic aromatic hydrocarbons bioavailability in coal–tar-contaminated soils     

P. H. Lee  K. P. Chao  S. K. Ong 《International Journal of Environmental Science and Technology》2014,11(7):1999-2008

A solvent–water extraction method was proposed as an assessment tool to estimate the bioavailability of polycyclic aromatic hydrocarbons in coal–tar-contaminated soils. The approach taken was to measure the percent of polycyclic aromatic hydrocarbons extracted by a solvent–water mixture and comparing the results with the percent of polycyclic aromatic hydrocarbons degraded in a soil slurry reactor. Five soil samples from three former manufactured gas plant sites and a coal–tar disposal site which were operated between 1880 and 1947, and 1945 and 1950, respectively, in Iowa, USA were used in this study. Extraction experiments were conducted using acetone–water or ethanol–water mixtures with solvent volume fractions ranging from 1.0 to 0.4 (v/v). The percent of polycyclic aromatic hydrocarbons extracted from the various soils decreased as the volume fraction of the solvent in the solvent–water mixture was reduced. An acetone–water mixture of 0.6 was found to be appropriate in correlating the percent of polycyclic aromatic hydrocarbons degraded to the percent of polycyclic aromatic hydrocarbons extracted. For the first correlation, the percent extracted and the percent biodegraded were modified by using the molecular weights and log K _ow of polycyclic aromatic hydrocarbons, respectively. For the second correlation, the equation relating the percent extracted and the percent biodegraded was modified using soil properties such as organic carbon content and percent of clay and silt. Although the experiments were conducted for a limited number of soils, the extraction method appeared to be a good starting point in estimating the bioavailability of polycyclic aromatic hydrocarbons in coal–tar-contaminated soils.  相似文献