A pragmatic approach to study the groundwater quality suitability for domestic and agricultural usage,Saq aquifer,northwest of Saudi Arabia

The present study deals with detailed hydrochemical assessment of groundwater within the Saq aquifer. The Saq aquifer which extends through the NW part of Saudi Arabia is one of the major sources of groundwater supply. Groundwater samples were collected from about 295 groundwater wells and analyzed for various physico-chemical parameters such as electrical conductivity (EC), pH, temperature, total dissolved solids (TDS), Na⁺, K⁺, Ca²⁺, Mg²⁺, CO₃ ^?, HCO₃ ^?, Cl^?, SO₄ ^2?, and NO₃ ^?. Groundwater in the area is slightly alkaline and hard in nature. Electrical conductivity (EC) varies between 284 and 9,902?μS/cm with an average value of 1,599.4 μS/cm. The groundwater is highly mineralized with approximately 30 % of the samples having major ion concentrations above the WHO permissible limits. The NO₃ ^? concentration varies between 0.4 and 318.2 mg/l. The depth distribution of NO₃ ^? concentration shows higher concentration at shallow depths with a gradual decrease at deeper depths. As far as drinking water quality criteria are concerned, study shows that about 33 % of samples are unfit for use. A detailed assessment of groundwater quality in relation to agriculture use reveals that 21 % samples are unsuitable for irrigation. Using Piper’s classification, groundwater was classified into five different groups. Majority of the samples show Mix-Cl-SO₄- and Na-Cl-types water. The abundances of Ca²⁺ and Mg²⁺ over alkalis infer mixed type of groundwater facies and reverse exchange reactions. The groundwater has acquired unique chemical characteristics through prolonged rock-water interactions, percolation of irrigation return water, and reactions at vadose zone.     

Conclusion to the Featured Series on Satellites and Transboundary Water: Emerging Ideas1

Hossain, Faisal, 2010. Conclusion to the Featured Series on Satellites and Transboundary Water: Emerging Ideas. Journal of the American Water Resources Association (JAWRA) 46(4): 663-664. DOI: 10.1111/j.1752-1688.2010.00449.x     

Moderation of dust explosions

Inherent safety is a proactive approach to process safety in which hazards are removed or minimized so as to reduce risk without engineered (add-on) or procedural intervention. Four basic principles are available to attain an inherently safer design—minimization, substitution, moderation, and simplification. The subject of the current paper is the principle of moderation as it applies to the prevention and mitigation of dust explosions.

Moderation can be achieved by processing a material under less severe operating conditions or by processing the material in a less hazardous form. With respect to the latter approach, it may be possible to alter the composition of a dust by admixture of solid inertants, or to increase the dust particle size so as to decrease its reactivity. Additionally, avoidance of the formation of hybrid mixtures of explosible dusts and flammable gases is an application of moderation of the material hazard.

Several examples are given for each of the above three forms of moderation. The discussion on admixture of solid inertants includes examples from the following industrial applications: (i) refractory materials manufacturing, (ii) food processing, (iii) power generation, (iv) industrial recycling, and (v) foundry shell mold fabrication. The importance of particle size consideration is explained first from the perspective of engineering tools such as the Dow Fire & Explosion Index, and professional guidance on the definition of a dust and suitable particle sizes for explosibility testing. Industrial examples are then drawn from the following areas: (i) rubber recycling and textile manufacturing, (ii) industrial recycling, (iii) wood processing, (iv) dry additive handling (polyethylene facility), (v) polyethylene production, (vi) carbon block recycling, and (vii) coal mining. The concluding discussion on hybrid mixtures includes brief cases from the process safety literature.     

Uncertainty-based quantitative assessment of sustainability for higher education institutions

Evaluation of sustainability in various facets of life is gaining increasing importance. Traditionally, different multi-criteria decision-making methods have been used for sustainability assessment. “Sustainability” can be a qualitative concept, and as such several researchers have attempted fuzzy logic for the quantitative assessment of sustainability. This paper outlines a new evaluation model based on fuzzy multi-criteria decision-making. The model is tested for sustainability assessment of higher education institutions (HEIs). It is based on a driving force–pressure–state–exposure–effect–action (DPSEEA) framework and is called uncertainty-based DPSEEA-Sustainability index Model (uD-SiM). The uD-SiM is a causality-based model in which the sustainability index is an outcome of nonlinear impacts of sustainability indicators in different stages of DPSEEA. The percent contribution of driving forces on the sustainability index of HEI is investigated using sensitivity analysis. The study reveals that education in sustainability and global and local research trends are the major driving forces for achieving sustainability in HEI, followed by financial and economic growth rate, social equity, energy requirements rate, and institutional enhancement, in descending order. The results of uD-SiM were found to be more realistic and rational than our earlier proposed approach, D-SiM.     

Toxicity of the nerve agent tabun to Daphnia magna, a new experimental species in military toxicology

Daphnia magna, a freshwater microcrustacean, is currently tested as an alternative experimental species in research dealing with nerve agents poisonings treatment. Because of this, the toxicity of the nerve agent tabun (a cyanide-group containing organophosphate) to Daphnia had to be examined by estimating the EC₅₀ values. The immobilization of daphnids was chosen as the end-point. It was found that D. magna is sensitive to small amounts of tabun, even after 15 min exposure, and tabun toxicity increases with time. The estimated EC₅₀ values for 15, 30, 45, and 60 min exposure were as follows: 67.39, 38.10, 26.95, and 21.9 μg l^-1. In addition, the toxicity of media to which tabun was added 24 h before the start of experiments was examined. The results obtained indicate that daphnids can be used in experiments with nerve-agent intoxication treatment.     

Third party roles played by Turkish managers in subordinates' conflicts

This study investigated the third party roles of Turkish managers and how these roles were related to the conflict management styles used by their subordinates. Questionnaire data were collected from 295 Turkish managers in seven firms. Mediation and facilitation were found to be the third party roles reported more frequently than autocratic intervention and laissez-faire. Subordinates reported increased use of collaboration and compromise toward the other party when their managers, in a third party role, were seen as using more mediation and facilitation. Competitive behavior increased when the third party was seen as autocratic. The paper discussed the relationship of these findings to cultural characteristics such as uncertainty avoidance and collectivism.     

Risk-based asset integrity indicators

Asset integrity is a major concern of process facilities. Monitoring and assessing asset integrity is a challenging task due to the involvement of various dependent and independent parameters. Monitoring and assessing asset performance through indicators is one easily doable option. Lack of an appropriate set of indicators quantification technique and measurement cohesion limits the use of an indicator system. To overcome this, in the present paper a hierarchical framework is prepared to for asset integrity monitoring and assessment. The hierarchical structure is used to characterize the asset and relate it to an organization’s strategic goal. The hierarchical structure is based on three major areas of asset integrity, namely: mechanical, personnel and process. Further, it provides an opportunity to follow a bottom-up perspective for identifying multilevel level indicators. The proposed approach uses a risk metric to classify asset integrity through the integration of leading and lagging indicators’ outcome. The analytical hierarchy process is used to determine the weights, or for prioritization of each level indicator and for the aggregation of the indicators to classify risk. To test the proposed model, a benchmark study is conducted. The estimated asset integrity index value provides a tangible asset’s performance index. The system of indicators and their integration provide a comprehensive view of the process facility’s status and also reveal which sections of the facility need more attention.     

Fugitive emissions in chemical processes: The assessment and prevention based on inherent and add-on approaches

Fugitive emissions are among the major concerns of industrial process releases. The emissions cause problem to various aspects including the environment, health, and economic. Early evaluation of process hazards is beneficial because process can be made inherently benign at lower cost. This paper discusses two important aspects of fugitive emissions assessment during process design – the quantification and the prevention strategies.For the quantification part, three methods are presented for fugitive emissions estimation during the process design. They are tailored to data available in simple process flow diagram (PFD), detailed PFD, and piping & instrumentation diagram (PID). Such methods are needed as early emissions estimation allows production routes and process designs with lower emissions to be selected. The fugitive emissions estimation and methods to abatement are demonstrated on a benzene process case study. Valves are found to be the major emission source with 50% of fugitive emissions of process area in a base case of petrochemical process, in which no fugitive emission reductions are yet made. Pumps without mechanical seals come second with 30% and flanges with 8% of emissions. Inherently safer design keywords can be applied to prevent fugitive emissions in the process plants. Substitution is the most applicable keyword in fugitive emission reduction of existing plants.The emission rate calculations together with estimation of health risk give a sound background for the decision making on elimination of emissions at source through equipment and piping changes. The case study presented reveals that by substituting emission prone components by inherently low-leaking ones, the plant emissions can be reduced over 90% in practice. This is created mainly by replacing rising stem valves with ball valves, installing double mechanical pump seals or hermetic pumps and making changes in sampling and relief systems. Ideally by also changing flanges to welded connections, which is not viable for various reasons, the emissions could be reduced nearly to zero.     

Proposed formulation of surface water quality and modelling using gene expression,machine learning,and regression techniques

Environmental Science and Pollution Research - The rising water pollution from anthropogenic factors motivates further research in developing water quality predicting models. The available models...     

Assessment of patients' medical fitness to drive by primary care physicians: A cross-sectional study

Objectives: Motor vehicle collisions (MVCs) are a significant health burden in Saudi Arabia. The literature has consistently indicated that chronic medical conditions, such as diabetes, heart disease, stroke, obstructive sleep apnea, and neurodevelopmental disorders, increase the risk of MVCs. Therefore, assessment of driver fitness by primary care physicians (PCPs) remains a major health intervention that might reduce MVCs. We studied the practices of PCPs in assessing medical fitness to drive in at-risk patients.

Methods: We conducted a cross-sectional study of all 88 government-funded primary care centers in the city of Riyadh, Saudi Arabia. We administered a self-reported questionnaire to PCPs that inquired about their driving risk assessment for specific medical conditions.

Results: Among all PCPs and centers, 189 PCPs (63%) from 74 centers (84%) participated in our survey. The mean age of the PCPs was 40 ± 10 years, and 108 (57%) were men. The average clinical experience of the group was 13 ± 9 years. Fewer than half of PCPs considered diabetes mellitus (45%) and obstructive sleep apnea (46%) as potential risks for MVCs. Approximately 45% of PCPs did not notify any authority or relatives of potential driving issues that they noticed in their patients. Only 15% of the participants believed that PCPs were responsible for alerting authorities about their fitness to drive.

Conclusions: PCPs did not adequately assess their patients' driving history and eligibility. Efforts are needed to improve awareness among PCPs regarding the effects of chronic medical conditions on driving.