Environmental isotopic and hydrochemical study of water in the karst aquifer and submarine springs of the Syrian coast

The groundwater of major karst systems and submarine springs in the coastal limestone aquifer of Syria has been investigated using chemical and isotopic techniques. The δ¹⁸O values of groundwater range from ?6.8 to ?5.05‰, while those for submarine springs vary from ?6.34 to +1.08‰ (eastern Mediterranean seawater samples have a mean of +1.7‰). Groundwater originates from the direct infiltration of atmospheric water. Stable isotopes show that the elevation of the recharge zones feeding the Banyas area (400–600 m a.s.l.) is higher than that feeding the Amrit area (100–300 m a.s.l.). The ¹⁸O_extracted (¹⁸O content of the seawater contribution) for the major submarine springs suggests a mean recharge area elevation of 600–700 m a.s.l., and lower than 400 m a.s.l. for the spring close to Amrit. Based on the measured velocity and the percentage of fresh water at the submarine springs outlet, the estimated discharge rate is 350 million m³/year. The tritium concentrations in groundwater (1.6–5.9 TU) are low and very close to the current rainfall values (2.9–5.6 TU). Adopting a model with exponential time distribution, the mean turnover time of groundwater in the Al-sen spring was evaluated to be 60 years. A value of about 3.7 billion m³ was obtained for the maximum groundwater reservoir size.     

Malaria and related environmental issues in India: a case study of Aligarh city

Malaria is one of the most widespread diseases in the world. Endemic malaria no longer occurs in many temperate zones as a result of social and economic improvement. At present malaria is the Third World's most dreaded killer. It kills over 1 million people and causes 300–500 million episodes of illness. In India, malaria-reported deaths have shown an upward trend. In 1955, a drive to eradicate malaria was launched in India. But after initial success it failed and malaria made a comeback. Malarial mosquitoes generally prefer unpolluted natural breeding sites but now they have adapted to the changed urban environment. In this paper, an attempt has been made to examine the occurrence of malaria and related environmental issues in a small town of India. Aligarh city, lying in the shadow of the country's capital New Delhi, was selected as a case study. Data were collected mainly from household surveys with the help of questionnaire interviews. About 2,185 households belonging to different income groups were sampled. The differences in the occurrence of malaria in the different income households (in 87% low, 69% lower-middle, 65% middle, 14% upper-middle, and 5% upper) suggest that most of these differences are related to the environmental conditions existing inside and outside their homes, such as poor drainage system, poor sullage disposal, open blocked drains, waterlogging and indoor water storage in open containers. Commitment both by the Government and local residents is needed to improve the environmental conditions and eradicate malaria.     

A minimalistic approach for evapotranspiration estimation using the Prophet model

ABSTRACT

This study aimed to evaluate the potential of the recently introduced Prophet model for estimating reference evapotranspiration (ETo). A comparative study was conducted for benchmarking the model results with support vector regression (SVR) and temperature-based empirical models (Thornthwaite and Hargreaves) in southern Japan. The performance of the Prophet, SVR and temperature-based empirical models was evaluated by Nash–Sutcliffe efficiency (NSE) and coefficient of determination (R²). The results indicate that temperature-based Prophet and SVR models have greater accuracy than the empirical models. The Prophet model with sole input of relative humidity, sunshine hours or windspeed showed acceptable accuracy (NSE > 0.80; R² > 0.80), while SVR models with similar inputs showed greater errors. Accuracy improved with increasing number of input parameters, giving excellent performance (NSE > 0.95; R² > 0.95) with all input parameters. Hence, the Prophet model is a new promising approach for modelling ETo with limited input variables.     

Electricity consumption patterns within cities: application of a data-driven settlement characterization method

ABSTRACT

Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns.     

Titanomagnetites prepared at different oxidation conditions: Influence of magnetite-rich inclusions

Synthetic titanomagnetites prepared at 1300°C at different oxidation potentials, although giving only spinel-type X-ray reflections, were found to contain a small amount of included material with a Curie point above that for the bulk material. Specimens, comprising either dispersed sized grains, or polycrystalline spherical aggregates of grains, develop thermoremanent moments which are dependent upon the presence of the inclusions. The magnetization of the inclusions is revealed by thermal demagnetization experiments, and the experimental results are compared with the effects expected to arise from magnetic shielding by the matrix titanomagnetite.     

Analysis of the vajont slide — new approach

SummaryAnalysis of the Vajont Slide — New Approach This paper is concerned with the analysis of the 1963 Vajont slide in Italy. Attention is drawn to the fact that numerous investigations have been consistently unsuccessful in explaining the slide. A new approach consistent with a progressive failure mechanism established by all comprehensive investigations is suggested in this paper. The analysis simulates the transformation of the slope from a condition of stability to one of limit-equilibrium and failure in a step-by-step process. It is shown that the enormous velocities calculated on the basis of external observations of the slide can be explained by the new analytical approach.

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ZusammenfassungAnalyse der Felsgleitung bei Vajont — Neuer Erklärungsversuch Dieser Artikel beschäftigt sich mit der Felsgleitung bei Vajont in Italien im Jahre 1963. Es wird darauf hingewiesen, daß es in einer Vielzahl anderer Untersuchungen bislang nicht möglich war, eine Erklärung für die Felsgleitung zu finden. Ein neues Modell, basierend auf dem Mechanismus des progressiven Zusammenbruchs wird vorgeschlagen. Die Untersuchung simuliert den Übergang des Hanges vom stabilen Zustand in ein Grenzgleichgewicht und schließlich den Zusammenbruch in einem Prozeß, der Schritt für Schritt abläuft. Es wird gezeigt, daß die enormen Geschwindigkeiten, die aufgrund von Beobachtungen berechnet wurden, im Rahmen dieses Modells erklärt werden können.

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RésuméAnalyse de l'éboulement de Vajont — Nouvelle approche Cette communication constitue une analyse de l'éboulement de Vajont (Italie) en 1963. On souligne le fait que les nombreuses enquêtes entreprises pour expliquer cet éboulement se sont montrées infructueuses. Cette communication propose une nouvelle approche conforme à un mécanisme progressif de défaillances établi par toutes les enquêtes compréhensives. L'analyse simule la transformation graduelle de la pente: de la stabilité à l'équilibre limité et enfin à la défaillance. On démontre que les vélocités énormes calculées à base des observations externes de l'éboulement peuvent s'expliquer par cette nouvelle approche analytique.

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Notation c unit effective cohesion - ø effective angle of shearing resistance (residual) - n proportion of the slip surface along which failure has progressed - K conjugate stress ratio for a slope - K ₀ ratio of effective horizontal normal stress to effective vertical normal stress in the slope With 3 Figures     

Response of saturated and nearly saturated porous media: Different formulations and their applicability

The response of saturated porous medium is of significant interest in many fields ranging from geomechanics to biomechanics. Biot was the first to formulate the basic equations governing the process of coupled flow and deformation in porous media. Depending on the nature of loading vis‐à‐vis the characteristics of the media, different formulations (fully dynamic, partly dynamic, quasi‐static) are possible. In this study, analytical solutions are developed for the response of saturated and nearly saturated porous media under plane strain condition. The solutions for different formulations are developed in terms of non‐dimensional parameters. The response is studied for various conditions and the regions of validity for various formulations are identified in a parametric space. An assessment of the needed formulation for few important problems is also presented. Copyright © 2008 John Wiley & Sons, Ltd.     

Probabilistic stability assessment of slopes using high dimensional model representation

This paper presents a new computational tool for probabilistic stability assessment of earth slopes/embankments. The method involves high dimensional model representation (HDMR) that facilitates lower dimensional approximation of the original limit state, response surface generation of HDMR component functions, and Monte Carlo simulation. HDMR is a general set of quantitative model assessment and analysis tools for capturing the high-dimensional relationships between sets of input and output model variables. It is a very efficient formulation of the system response, if higher-order variable correlations are weak, allowing the physical model to be captured by the first few lower-order terms. Once the approximate form of the original limit state is defined, the failure probability can be obtained by statistical simulation. Results of four numerical examples indicate that the proposed method provides accurate and computationally efficient estimates of the failure probability of earth slopes/embankments.