Synthesis and characterization of (poly (N-vinyl formamide)—pregelled starch—graft copolymer

Bromate / cyclohexanone redox system was investigated as a novel initiator for graft copolymerization of N-vinyl formamide onto pregelled starch. A number of variables in the grafting reaction were investigated including N-vinyl formamide, cyclohexanone, bromate ion, sulphuric acid and pregelled starch concentrations, material to liquor ratio along with polymerization time and temperature. The graft copolymers were evaluated in terms of graft yield, graft reaction efficiency and homopolymer formation (%). The optimum conditions for grafting of N-vinyl formamide onto pregelled starch are: N-vinyl formamide 50% based on weight of substrate, cyclohexanone 15 mmol / l, bromate ion, 30 mmol / l, liquor ratio 10, pH 6, time 120 min., and temperature 40°C. On the other hand, characterizations of the resultant copolymers with respect to swelling capacity, solubility %, metal ion up-take and suitability as a sizing agent for cotton textiles were investigated. The results obtained reflect that, the resultant copolymer shows better results for the aforementioned properties in comparison with that obtained from native pregelled starch as a starting substrate.     

Electrochemical behavior of nickel in nitric acid and its corrosion inhibition using some thiosemicarbazone derivatives

The adsorption and corrosion inhibition behavior of three selected thiosemicarbazone derivatives, namely 3-pyridinecarboxaldehyde thiosemicarbazone (META), isonicotinaldehyde thiosemicarbazone (PARA) and 2-pyridinecarboxaldehyde thiosemicarbazone (ORTHO) at the nickel surface were studied electrochemically by Tafel and impedance methods and computationally by carrying out Monte Carlo searches of configurational space on nickel/thiosemicarbazone derivative system. Electrochemical measurements showed that the inhibition efficiency of these compounds increased with increase in their concentration. The recorded inhibition efficiencies of the three tested thiosemicarbazone increase in the order: META > PARA > ORTHO. Polarization studies showed that these compounds act as mixed-type inhibitors for nickel corrosion in 1.0 M HNO₃ solutions. Results obtained from Tafel and impedance methods are in good agreement. Thiosemicarbazone derivatives have been simulated as adsorbate on Ni (1 1 1) substrate and the adsorption energy, binding energy and the low energy adsorption sites have been identified on nickel surface.     

Enhanced anti-biofilm activity of facile synthesized silver oxide nanoparticles against K. pneumoniae

Journal of Inorganic and Organometallic Polymers and Materials - The silver oxide nanoparticle was successfully synthesized using floral waste by simple one pot, cost effective method. The complete...     

GIS and Multi-Criteria Evaluation: Robust Tools for Integrated Water Resources Management

Abstract

Integrated water resources planning and management are considered very complex issues. These issues are usually addressed through the multi-sectoral, interdisciplinary and hierarchal decomposition approaches. In general, integrated resource management indicates the consideration of water, social, socio-economic, economic and environmental issues. The current study aims at merging the GIS and Multi-Criteria Evaluation (MCE) techniques for the integrated water resource management of a cropped area. An area of about 120,000 Hectares located in the Northern Nile River Delta area with a coastal zone on the Mediterranean was selected and GIS was applied to represent the area's different environment, social, economic, and water factors. Different randomization cropping pattern distribution scenarios were proposed. Through the merging of GIS and MCE approaches, three scenarios were run and evaluated at three different levels: farm, canal catchment area and whole area. This merging resulted in a very powerful tool for the evaluation of different plans. The merging of GIS and MCE really facilitated the decision making process for these types of integrated water management problems.     

THERMAL STRESSES FOR AN INFINITE BODY WITH A SPHERICAL CAVITY WITH TWO RELAXATION TIMES

Thermoelastic interactions caused in a homogeneous and isotropic infinite body with a spherical cavity are considered for the two different theories of generalized thermoelasticity, that is, Lord, and Shulman's theory and Green and Lindsay's theory. Analytical expressions for the temperature, displacement, and thermal stress fields are obtained; and the results are compared with the classical dynamical coupled theory.     

Estimated daily intake of pesticide residues exposure by vegetables grown in greenhouses in Al-Qassim region,Saudi Arabia

Residues of 23 pesticides (13 insecticides, 3 fungicides, 3 herbicides, 2 acaricides, 1 rodenticide and 1 nematicide) in 160 different vegetable samples cultivated under greenhouse conditions and collected from 4 major supermarkets located in Al-Qassim region, Saudi Arabia were monitored. A multiresidue method was carried out by gas chromatography with mass spectrometry (GC–MS). Residues were found in 89 samples. Fifty four samples were found above the maximum residue levels (MRLs). The most frequently found pesticides were carbaryl followed by biphenyl and then carbofuran. MRL values exceeded most often in cabbage (11 samples) followed by squash, green pepper and carrot (7 samples each) followed by cucumber and lettuce (6 samples each), egg-plant (5 samples) and then tomato (4 samples). Also, cabbage showed the highest contamination rates (16 samples), followed by carrot, cucumber and green pepper (12 samples each), squash (11 samples), lettuce and tomato (9 samples each) and egg-plant (8 samples). The highest concentrations were determined in lettuce followed by squash, cabbage and carrot. Al-Qassim region population’s average daily intake (EDI) has been estimated between 2 × 10^?5 and 0.597 μg/kg body weight/day and the hazard index (EDI/acceptable daily intake (ADI)) less than the unity for the tested compounds. The data illustrated that the intakes are much lower than the ADIs and the exposure level to whole pesticides was below the level to produce health risk. The data indicated also the need for regular monitoring programs for pesticide residues in vegetables cultivated under greenhouse conditions, at the national level, to protect consumers’ health.     

Changes in quality and phenolic compounds of virgin olive oils during objectively described fruit maturation

The effect of fruit ripening on the quality of the oil extracted and on the changes in the amount of phenolic compounds was determined in two olive varieties (Olea europaea, cvs. Arbequina and Picual) in two crop seasons, characterized by showing the same mean temperature and different rainfalls. Maturation level was evaluated using six methods: Harvest date, ripening index (RI), fruit skin colour, fruit firmness, and amount of chlorophylls and carotenoids in the oil. Oil quality, evaluated using the parameters established to determine the quality level of virgin olive oils (acidity, K₂₃₂, K₂₇₀, peroxide index, and panel test), was not affected by fruit ripening or by the increase in rainfall of the season. However, the changes in oil stability and phenolic compounds in the oils extracted during fruit ripening strongly differed according to the variety, the maturity level of the fruit and the crop season tested. Fruit skin colour and firmness allowed a better discrimination at the initial maturity stages than the other methods tested.     

Experimental study on the compressive resistance of stress-relieved solid round steel members

The Canadian Standard for Antenna Towers and Antenna Supporting Structures, CSA-S37-01, specifies expressions for the compressive resistance of solid rounds based on the Structural Stability Research Council (SSRC) Column Curves for non-solid-round members and the results from experimental investigations on the compressive resistance of solid rounds carried out back to 1965. Similar Standard in USA (TIA/EIA-222-G.0) specifies design criteria for such members as derived from the superseded AISC-LRFD-94 Standard, which is independent of the shape of the member cross-section. The European Standard, Eurocode 3, provides column curves for the compressive resistance of various structural steel members, and assumes the applicability of one of them to solid rounds. As such, it is necessary to conduct an experimental study on solid round stress-relieved steel members to refine the available design equations for such members. This paper provides a summary of the literature review on solid rounds as well as a recent test program conducted on stress-relieved steel solid rounds. Correlation between the results from these tests and the current practice for the design of solid rounds is investigated. The paper concludes with a proposed compressive resistance equation for economical design of such members.     

Analysis of deformations and stresses in balanced and unbalanced adhesively bonded single-strap joints

Adhesively bonded joints are increasingly being used in joining various structural components. Adequate understanding of the behaviour of adhesively bonded joints is necessary to ensure efficiency, safety and reliability of such joints. While several joint configurations, such as the single- and double-lap joints have received considerable consideration, the single-strap joint configuration has received little attention, partly because earlier studies have shown it to be the least efficient.

One of the objectives of this paper is to demonstrate that strap joints can be as efficient as lap joints, as long as they are properly designed. This will be done through a detailed analytical investigation into influence of the parameters that govern peak stresses in the adhesive. The next objective is to produce simple equations by which the design of strap joint could be facilitated in an effective manner. For this, the developed analytical expressions are simplified and shown to provide accurate results. The derived solutions provide better insight into understanding the parameters that most influence the edge forces.