Levels and distributions of organic source tracers in air and roadside dust particles of Kuala Lumpur,Malaysia

The concentrations of n-alkanes, unresolved complex mixture (UCM), petroleum molecular markers, other tracers of cooking and burning emissions, and natural background in atmospheric particles and roadside dust particles were measured at eight locations in the city center and the suburbs of Kuala Lumpur, Malaysia. Atmospheric particles were collected using high-volume filtration (PM-10, GFF) over 24 h average periods. Road dusts were swept up, dried and sieved. Both types of samples were extracted with dichloromethane/methanol mixture (3:1 v/v) by ultrasonic agitation. The extracts were then fractionated by column chromatography and the alkanes subjected to gas chromatography–mass spectrometry (GC–MS). Total extracts were also analyzed directly by GC–MS after silylation. The molecular distributions of compounds as well as diagnostic geochemical ratios were determined in order to identify the sources of the organic compounds. Samples collected from a rural area and lubricating oils were also analyzed for comparisons. Anthropogenic and biogenic sources such as vehicular emissions, waxes of higher plants, food cooking operations, and biomass and domestic refuse burning processes contributed to the organic matter content of atmospheric and to lesser extent, roadside dust particles.     

Compressibility of porous rocks: Part II. New relationships

Pore volume compressibility is one of the physical properties of a reservoir that must be specified in many reservoir-engineering calculations. The main objective of this work is to provide new general formulas for pore volume compressibility versus porosity on the basis of measured compressibilities of some limestone and sandstone rocks in a wide range of porosity values and of varied type; the measurements were performed on Hungarian reservoir rock samples. The obtained laboratory results were compared with the published correlations of consolidated limestone samples as well with values for friable and strongly consolidated sandstones. The validity of using compressibility data from the literature was investigated. The measured data showed poor agreement with the published correlations. The first approach to find better and more accurate rock compressibility correlations consisted of combing all the data available from the literature, using the same formula of Horne’s type. However, this attempt did not give satisfying fitting results. In the next step, by using twelve different fitting formulas, and other comprehensive nonlinear fitting regression programs, new rock compressibility correlations for limestone and sandstone rocks, with better goodness of fit, were developed. These new correlations can be generalized and used for most of oil and gas reservoirs.     

Spatial and temporal variation of rainwater stable isotopes in Egypt and the east Mediterranean

Summary ?By analyzing normalized variables, it was found that the latitudinal secular variations of the rainwater deuterium fractionation ratio δ²H, oxygen fractionation ratio δ¹⁸O, vapor pressure, and surface temperature were almost non-linear, occurred in parallel, and decreased with latitude. The rate of depletion around the equator is asymmetric and smaller to the south of 45° S than to the north of 45° N. In the east Mediterranean, the rate of change of δ¹⁸O with height was found to be −.2‰ per 100 m and that of δ²H is comparable with the dry lapse rate in the atmosphere. Analysis of the annual time series of δ²H at Alexandria has indicated that variations show sinusoidal waveform with a major cycle of two years that accounts for 68% of the total variance. Although the quasi-biannual cycle in the atmosphere has small amplitude in the lower layers of the atmosphere at East Mediterranean latitudes, the major cycle in annual series of δ²H or δ¹⁸O may be linked to the quasi-biannual oscillation in the atmosphere. It was also found that the first three Empirical Orthogonal Functions (EOF) account for 72% of the seasonal variation of δ²H and share 68% of the seasonal variation of δ¹⁸O. Share of variances of monthly EOF in the months of the year indicate that the main underlying factors that cause fractionation processes for δ²H and δ¹⁸O are similar across the east Mediterranean especially in late winter and early spring. Received May 13, 2002; revised July 8, 2002; accepted August 6, 2002     

Biostratinomy and facies analysis of the upper Cretaceous oyster storm shell beds of the Duwi formation, Qusseir District, Red Sea Region, Egypt

The Maastrichtian oyster Lopha villei (Coquand) occurs abundantly in the upper part of the Duwi Formation in the Red Sea region, Egypt. It forms thin undulating sharp-based shell beds that comprise both reclining and encrusting morphotypes of Lopha villei. Bed-by-bed biostratinomic and facies analyses of these shell beds confirm their shallow marine origin and formation by storm events. A tempestite model, explaining the mode of formation and the idealized sequence of events of such storm shell beds, has been inferred.     

Elasto-plastic earthquake shear-response of one-dimensional earth dam models

A simplified analysis procedure for the non-linear hysteretic earthquake-response of earth dams is presented. The dam is modelled as a one-dimensional hysteretic shear-wedge subjected to base excitation. The hysteretic stress-strain behaviour of the dam materials is modelled by using elasto-plastic constitutive equations based on multi-surface kinematic plasticity theory. The method is based on a Galerkin formulation of the equations of motion in which the solution is expanded using eigenmodes of the linearized problem defined over the spatial domain occupied by the dam. The technique is applied to analyse the non-linear dynamic response of an earth dam subject to two very different input ground motions. The following investigations are presented: (i) comparison between the results obtained using two soil models depicting different nonlinear properties, (ii) comparison between the results of the one-mode and the multi-mode solution expansions, (iii) comparison with the results obtained through an elaborate finite element representation of the dam, and finally, (iv) comparison with the results obtained through the Makdisi-Seed¹¹ iterative procedure for earth dam analysis. The comparisons show that the proposed technique can be used to determine adequately the transient earthquake response of long earth dams. Furthermore, the efficiency and low computational cost make the technique very attractive; it can easily and systematically be extended to two- and three-dimensional calculations of earth dam response.     

Momentum flux variations at lower thermospheric levels as seen from mid-latitude meteor wind observations

Summary Computations of momentum flux were made for the meteor wind data collected at Atlanta (34°N), during the period August 1974–March 1978. Substantial transport of momentum due to diurnal tide during summer and semidiurnal tide during winter was observed over the station. Monthly mean momentum flux variations of diurnal and semidiurnal tides exhibited oscillations with periods of about six and four months respectively. The height variations of annual mean momentum flux due to diurnal and semidiurnal tides revealed poleward flux throughout the height region 82–98 km and severe damping of momentum flux due to diurnal tide between the heights 90 and 92 km. The results of the present study relating to the northern hemisphere mid-latitude station are compared with those of Adelaide (35°S), the southern hemisphere mid-latitude station.

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Zusammenfassung Es wurden Impulsflußberechnungen für die in Atlanta (34°N) von August 1974 bis März 1978 gesammelten Meteor-Winddaten gemacht. Über der Station wurde ein beträchtlicher Impulstransport, der durch Tagesgezeiten während des Sommers und Halbtagesgezeiten während des Winter verursacht wurde, beobachtet. Die monatlichen, mittleren Impulsflußvariationen der Tages- und Halbtagesgezeiten zeigten Schwankungen mit sechsbzw, viermonatlichen Perioden. Die Höhenschwankungen des jährlichen, mittleren Impulsflusses infolge der Tages- und Halbtagesgezeiten zeigten einen polwärts gerichteten Flß innerhalb der Höhenregion von 82–98 km und eine heftige Dämpfung des Impulsflusses infolge der Tagesgezeiten zwischen 90 und 92 m Höhe. Die Ergebnisse dieser Untersuchung, die sich auf eine Station der mittleren Breiten in der nördlichen Hemisphäre bezieht, werden mit jenen von Adelaide (35°S), einer Station der mittleren Breiten in der südlichen Hemisphäre verglichen.

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With 3 Figures     

Rapid estimation of corrected cut point in hydrocyclone classification units

In dressing plants, the rapid determination of the corrected cut point in hydrocyclone classification is desirable, useful, and important. In this work, classification tests have been carried out on white sand using a 10-cm diameter hydrocyclone to examine closely the relation between the recovery to underflow and the corrected separation size, $\text{d}{}_{50}$. The study was carried out at wide ranges of: apex diameter, vortex-finder diameter, solid content of feed, and length of vortex finder.A simple, yet reliable, equation relating the solid recovery of underflow to $\text{d}{}_{50}$, is developed using all the obtained results. The predicted data show good agreement with the experimental.     

Exploring socio-hydrological determinants of crop yield in under-performing irrigation schemes: pathways for sustainable intensification

ABSTRACT

Understanding the human–water–food–climate nexus is central to achieving sustainable intensification (SI) in agriculture. This research uses a socio-hydrological approach to understand the underpinning for implementing SI in the Gezira Irrigation Scheme, Sudan, by integrating vegetation indices derived from remote sensing, ancillary, gridded soil and precipitation data, supplemented by interviews with 393 farmers. The productivity gap was estimated as the difference between the potential and actual productivities. Based upon data on farmers’ socio-economic status and field practices, a regression tree model was built to determine the factors that control the sorghum yield. The model revealed that the financial status of farmers and access to water are the most influential factors on sorghum yield. A conceptual framework that elucidates SI and its bi-directional feedback to the environment, society and the economy is proposed. Implementing SI in the scheme has implications on water and food security in Sudan and beyond its borders.     

Thermoregulation, water balance and plasma constituents in Sudanese desert sheep: responses to diet and solar radiation

The responses of desert rams to diet composition (concentrate vs. lucerne hay) in unshaded and shaded environments were investigated. The rectal temperature was higher (p < 0·01) with the concentrate diet but only in the afternoon, whereas the respiration rate was higher (p < 0·01) with the concentrate diet in unshaded and shaded environments during both morning and afternoon. Dry matter intake (DMI) was higher (p < 0·05) with the concentrate diet, while the ratio of water intake to DMI was higher (p < 0·01) with lucerne hay. Water gain through preformed and metabolic avenues and water loss through faeces and evaporative avenues were higher (p < 0·01) with the concentrate diet. With both diets, water turnover rate was higher (p < 0·05) in the unshaded environment. Feeding lucerne hay increased plasma total protein (p < 0·01) and albumin (p < 0·05) in unshaded and shaded environments. Plasma urea was higher (p < 0·01) with the concentrate diet. Plasma glucose level and plasma osmalality were higher (p < 0.01) and level of free fatty acids was lower (p < 0·01) with the concentrate diet in both thermal environments. Plasma cholesterol level was higher (p < 0·05) with the concentrate diet in the shaded environment, but lower (p < 0·05) in the unshaded environment. With lucerne hay, plasma cholesterol level remained the same in both environments.