Assessment of Groundwater Quality in a Structurally Deformed Granitic Terrain in Hyderabad, India

Geochemical study of groundwater from a structurally deformed granitic terrain near Hyderabad (India) was carried out to understand and evaluate the hydrogeochemical processes and quality of groundwater. Several trace elements (Fe, Mn, Be, Al, V, Cr, Co, Ni, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, Pb, U) along with major ions and minor elements were precisely estimated in shallow and drilled wells to know the suitability of water for drinking and irrigation purposes. Analytical data shows that pH and major ion chemistry in dug wells and bore wells do not vary significantly, while some trace elements (Fe, Mn, Al, Be, Co, Pb, U and Zn) vary in dug wells and bore wells, which can be attributed to differential mineral weathering and dissolution/precipitation reactions along fractures/joints. Although the water is not potable, it was found to be suitable for irrigation with little danger in the development of harmful level of exchangeable sodium. It is inferred that the chemical composition of the groundwater in this region is likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported by rainfall and groundwater flow.     

Applying physicochemical approaches to control phosphogypsum heavy metal releases in aquatic environment

One of the most important sources of solid waste in the Mediterranean Basin ecosystem originated from the phosphate fertilizer industries, which discharge phosphogypsum (PG) directly into aquatic environments or are stacked on stockpiles. The present study investigates metal release from PG under the influence of variable pH, increasing PG mass content, and complexing organic matter ligands. Major ions from PG leachates, grain size and charge, main functional groups along with metal leachability (Pb, Cd, Cr, Cu, and Zn) were determined using ion chromatography, laser diffraction, zetameter, Fourier transform infrared spectroscopy, and atomic absorption spectroscopy, respectively. The complete dissolution of PG recorded is at 2 g/L. Saturation and supersaturation with respect to PG may occur at concentrations of 3 and 4 g/L, respectively, revealing a clustering phenomenon leading to heavy metal encapsulation within the aggregates. Organic ligands such as citrate may trigger the cationic exchange within the PG suspension leading to ion release. As these factors are considered as specific process involving the release of contaminants from PG during storage under natural conditions, this study could set the foundations for PG remediation in aquatic environment. Organic ligands under controlled pH conditions could be utilized in treating fertilizer industrial wastes by taking into consideration the particularity of the receiving area, thus decreasing metal hazardous impact on natural media.     

Identification and Quantitative Analysis of Particulate Air Contaminants by X-Ray Diffraction Spectrometry

Because of the synergistic effects which take place from the mixing of gases and particulates in ambient air, it is important that the determination of air contaminants be carried out on the sample in its native state without imposing any further chemical recombination during the analysis. Since x-ray diffraction provides a chemically passive method of analysis and yields molecular rather than elemental information, we have undertaken the siudy of, and have successfully employed crystal diffraction lines as a qualitative and quantitative means for determining such materials as lime, calcium carbonate, road salt, coke dust, and aerosol from sinter emissions as well as several other less common industrial particulates in samples obtained from dustfall as dispersed in a matrix of powdered amorphous glass. Correlative to the above investigation this method was also extended to the study of such gases as sulfur dioxide which may be selectively fixed to an active surface.     

3D-QSAR of fungal quorum-sensing inhibiting analogs of farnesol

Thirty-four analogs with variable antifungal activity were selected to develop models for establishing three-dimensional quantitative structure-activity relationships (3D-QSAR). Comparative molecular field analysis (CoMFA) and comparative similarity indices analyses (CoMSIA) were conducted on the group of analogs to determine the structural requirements for selectivity and potency in inhibiting biofilm formation and fungal growth. The best CoMFA model predicted a q² = 0.5 and an r² = 0.991, and revealed that electrostatic properties play a significant role in potency and selectivity. The best CoMSIA model combined electrostatics, hydrogen bond acceptor and donor, and hydrophobic fields with a q² = 0.664 r² = 0.952, S = 0.099, and F = 139.892. The analyses of the contour maps from both models provide significant insight into the structural necessities for a potent compound. Therefore, manipulating various chemical properties of the substituted groups on the farnesol chain can be used to enhance the fungicidal properties of the target compound.     

Three-dimensional quantitative structure activity relationships of quorum-sensing and biofilm inhibitors in gram-negative bacteria

Thirty N-acyl homoserine lactone (AHL) analogs with variable antibacterial activity and displaying inhibition of biofilm formation were selected to develop models for establishing three-dimensional quantitative structure-activity relationships (3D-QSAR). Comparative molecular field analysis (CoMFA) and comparative similarity indices analysis (CoMSIA) were carried out to determine the optimum structural requirements for selectivity and potency of quorum-sensing and bacterial biofilm inhibition. The best CoMFA model predicted a q² value of 0.519 and an r² value of 0.984 and revealed that electrostatic and steric properties play a significant role in potency and selectivity. The CoMSIA model predicted a q² value of 0.411 and an r² value of 0.938 based on a combination of steric, electrostatic, and hydrophobic effects. The analysis of the contour maps from each model provide insight into the structural requirements for increasing the activity of a compound. Consequently, manipulating the chemical and physical properties of substituted acyl groups on the homoserine lactone moiety can provide important information toward enhancing the antibacterial properties of the target chemical compound.     

Spatial and temporal projected distribution of four crop plants in Egypt

This study focuses on the management of the local agroecosystems in order to adapt planting or sowing practices for the projected climate change scenarios. It is projected that there will be increased air temperature throughout all four seasons in the coming 100 years, from the southern towards the northern parts of Egypt. The objective of this study is to investigate the influence of that increased air temperature on the spatial and temporal distribution of four of the major economic crops in Egypt. The study species are cotton (Gossypium barbadense L., cv. Giza 89), wheat (Triticum aestivum L., cv. Gemiza 9), rice (Oryza stiva L., cv. Sakha 101) and maize (Zea mays L., cv. Hybrid 10). Optimum air temperature allowing maximum growth for each of the study crop cultivars and the current and projected air temperature patterns in the future years were used for projection of the seasonal and crop distribution maps in the years 2005, 2025, 2050, 2075 and 2100. Results showed that sowing dates of a target crop may be managed in order to allow maximum predicted planting area in the same region. The current maximum area suitable for planting the Cotton crop in Egypt (104 thousand Fadden/year; one Fadden = 0.96 hectare or 0.42 acre) showed few variations over the coming hundred years. In this case, the sowing dates should be changed from the hotter months (February to April) to the cooler months (January to February). Alternatively, a great reduction in the area planted by Wheat crop was predicted in the coming 100 years. Despite the early planting, a reduction of about 147 thousand Fadden/year was projected by the year 2075. On the other hand, with earlier sowing dates, the maximum areas that are planted by Rice and Maize may not be greatly affected by the projected increase in air temperature.     

Thermally assisted mechanical dewatering (TAMD) of suspensions of fine particles: analysis of the influence of the operating conditions using the response surface methodology

Thermally assisted mechanical dewatering (TAMD) is a new process for energy-efficient liquid/solids separation which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions (temperature <100 degrees C and pressure <3000 kPa) constitutes an original approach and a significant energy saving since the liquid is kept in liquid state. Response surface methodology was used to evaluate the effects of the processing parameters of TAMD on the final dry solids content, which is a fundamental dewatering parameter and an excellent indicator of the extent of TAMD. In this study, a two-factor central composite rotatable design was used to establish the optimum conditions for the TAMD of suspensions of fine particles. Significant regression models, describing changes on final dry solids content with respect to independent variables, were established with regression coefficients (usually called determination coefficients), R(2), greater than 80%. Experiments were carried out on a laboratory filtration/compression cell, firstly on different compressible materials: synthetic mineral suspensions such as talc and synthetic organic suspensions such as cellulose, and then on industrial materials, such as bentonite sludge provided by Soletanche Bachy Company. Experiment showed that the extent of TAMD for a given material is particularly dependent on their physical and chemical properties but also on processing parameters.     

Three-dimensional quantitative structure activity relationships of quorum-sensing and biofilm inhibitors in gram-negative bacteria

Thirty N-acyl homoserine lactone (AHL) analogs with variable antibacterial activity and displaying inhibition of biofilm formation were selected to develop models for establishing three-dimensional quantitative structure-activity relationships (3D-QSAR). Comparative molecular field analysis (CoMFA) and comparative similarity indices analysis (CoMSIA) were carried out to determine the optimum structural requirements for selectivity and potency of quorum-sensing and bacterial biofilm inhibition. The best CoMFA model predicted a q2 value of 0.519 and an r2 value of 0.984 and revealed that electrostatic and steric properties play a significant role in potency and selectivity. The CoMSIA model predicted a q2 value of 0.411 and an r2 value of 0.938 based on a combination of steric, electrostatic, and hydrophobic effects. The analysis of the contour maps from each model provide insight into the structural requirements for increasing the activity of a compound. Consequently, manipulating the chemical and physical properties of substituted acyl groups on the homoserine lactone moiety can provide important information toward enhancing the antibacterial properties of the target chemical compound.     

Recovery of aluminium, nickel-copper alloys and salts from spent fluorescent lamps

This study explores a combined pyro-hydrometallurgical method to recover pure aluminium, nickel-copper alloy(s), and some valuable salts from spent fluorescent lamps (SFLs). It also examines the safe recycling of clean glass tubes for the fluorescent lamp industry. Spent lamps were decapped under water containing 35% acetone to achieve safe capture of mercury vapour. Cleaned glass tubes, if broken, were cut using a rotating diamond disc to a standard shorter length. Aluminium and copper-nickel alloys in the separated metallic parts were recovered using suitable flux to decrease metal losses going to slag. Operation variables affecting the quality of the products and the extent of recovery with the suggested method were investigated. Results revealed that total loss in the glass tube recycling operation was 2% of the SFLs. Pure aluminium meeting standard specification DIN 1712 was recovered by melting at 800 degrees C under sodium chloride/carbon flux for 20 min. Standard nickel-copper alloys with less than 0.1% tin were prepared by melting at 1250 degrees C using a sodium borate/carbon flux. De-tinning of the molten nickel-copper alloy was carried out using oxygen gas. Tin in the slag as oxide was recovered by reduction using carbon or hydrogen gas at 650-700 degrees C. Different valuable chloride salts were also obtained in good quality. Further research is recommended on the thermodynamics of nickel-copper recovery, yttrium and europium recovery, and process economics.     

Pyruvate-utilizing bacteria as potential contributors to the food web in the Arabian Gulf

Water samples from the Kuwaiti coasts of the Arabian Gulf were used for counting and isolating bacteria capable of growth on low molecular weight organic compounds known to be released by picocyanobacteria. The compounds tested were potassium acetate, sodium pyruvate, fumaric acid, succinic acid, sodium citrate and glycerol. For comparison, the bacterial numbers on glucose (a conventional carbon source) and Tween 80 and crude oil (unconventional carbon sources), as sole sources of carbon and energy were also determined. Sodium pyruvate was, in most cases, the carbon and energy source most commonly utilized by the cultivable surface water bacteria. The most common cultivable bacterial genera on the test carbon sources were Pseudoalteromonas, Vibrio, Cobetia and Roseobacter. Less common genera were Rhodococcus, Pseudomonas and Bacillus. Quantification of heterotrophic bacteria associated with cultures of local picocyanobacterial strains, originally isolated from the Gulf surface water, also revealed that the carbon source most commonly utilized by cultivable bacteria was sodium pyruvate. However, a different bacterial composition was identified, with Alcanivorax, Stappia and Marinobacter as the major heterotrophic genera. All heterotrophic bacteria that grew on sodium pyruvate could also grow on β-alanine, as sole sources of carbon and energy. From this study we suggest that the Arabian Gulf bacteria utilizing picocyanobacterial low molecular weight compounds, particularly pyruvate may potentially contribute to the food web in this aquatic system. The experiments comply with the current laws of Kuwait.