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Sirte, Libya

Hander G.M.H.B.,Al Tahadi University
Research Journal of Chemistry and Environment | Year: 2011

A simple and sensitive spectrophotometric method is reported for the determination of manganese(II) based on its catalytic effect on the oxidation of nitrilotriacetatocobalt(II)-benzoate complex by periodate in acetate medium. The increase in absorbance of Co(III)-product was monitored at 580 nm, pH = 4.99, I = 0.5 M and T = 25 °C. The kinetics studied have been investigated under pseudo first order condition by taking large excess of oxidant. The various variables affect on sensitivity were studied and optimized and a study of interfering ions was also carried out. The calibration graph was linear in the range of 0.050-0.50 mol dm -3 acetate and (3.0 - 15.0) × 10 -5 mol dm -3 Mn(II). Mn(I1) in tap water, ground water and an industrial waste water has been successfully determined by the proposed method. Source


Tashani O.A.,Leeds Beckett University | Tashani O.A.,Leeds Pallium Research Group | Tashani O.A.,University of Benghazi | Alabas O.A.M.,Leeds Beckett University | And 4 more authors.
Gender Medicine | Year: 2010

Background: Studies have suggested that sex/gender, ethnicity, and anxiety toward pain affect pain sensitivity response. However, most studies have been conducted in a developed (Western) country, where the "ethnic" comparison group was in the minority. Objectives: This study measured the responses of Libyan men and women to cold pressor pain, and also examined the effect of anxiety about pain and of body characteristics such as height, weight, and body mass index (BMI) on pain responses. Methods: Students attending Garyounis University, Benghazi, Libya, took part in an experiment in 2007 that consisted of 2 cold pressor pain tests. During each test, participants plunged their nondominant hand into a slurry of ice. Time to pain threshold, time to pain tolerance (removal of the hand from the ice), and pain intensity and unpleasantness were measured using a 100-mm visual analog scale. Participants also completed a 20-item Pain Anxiety Symptoms Scale (PASS-20) questionnaire, with each item scored on a 6-point Likert scale anchored by descriptive phrases (0 = never, 5 = always). Results: Fifty-eight self-declared students (29 men, 29 women; age range, 1938 years) participated in the study. Pain threshold was significantly higher for men (mean difference, 8.2 sec; 95% CI, -1.7 to 18.0; P = 0.04), but there were no significant differences in pain tolerance, intensity, or unpleasantness. Women had significantly higher scores on the PASS-20 total score (P = 0.03), and on the PASS-20 dimensions of escape/avoidance (P = 0.04) and physiological anxiety (P = 0.006). Height, but not weight or BMI, was correlated with pain threshold in women (r = 0.52; P = 0.019) but not in men. Significant predictors of linearity of pain tolerance in women, but not men, were height (r = 0.49; P = 0.028) and the cognitive anxiety dimension score of the PASS-20 (r = -0.69; P = 0.004). Pain intensity rating was significantly higher in both women and men in the presence of an investigator of the opposite sex. Conclusions: Libyan women had higher pain sensitivity response to cold pressor pain than did Libyan men, but both sexes had lower pain responses than their Western counterparts. Height and anxiety may have contributed to the differences between the sexes in this study. © 2010 Excerpta Medica Inc. Source


Ewais H.A.,King Abdulaziz University | Hassun S.M.,Al Tahadi University
Oxidation Communications | Year: 2012

The oxidation of [Co II(nta)(M)(H 2O) 2] 3- by periodate has been studied kinetically in aqueous solution over 20.0∼40.0°C and a variety of pH ranges. The rate of oxidation of [Co II(nta)(M)(H 2O) 2] 3-by periodate, obeys the following equation: d[Co III] T/dt = (k 2K 3 + k 1 K 2 K 1/[H +]) [IO 4 -][Co II] 1(l + (K 1/[H +]) + (K 3 + K 1K 2[H +])[IO 4 -]) Initial cobalt(III) products were formed and slowly converted to final products, fitting an inner-sphere mechanism. Thermodynamic activation parameters have been calculated. A common mechanism for the oxidation of a ternary nitrilotriacetatocobalt(II) complexes by periodate is proposed and supported by an excellent isokinetic relationship between ΔH * and ΔS * values for these reactions. Source


Nasr A.M.A.,Tanta University | Nasr A.M.A.,Al Tahadi University
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2010

This paper presents the results of a series of plain-strain model tests carried out on both clean sand and oil-contaminated sand loaded with a rigid strip footing. The objectives of this study are to determine the influence of oil-contaminated sand on the bearing capacity characteristics and the settlement of the footing. Contaminated sand layers were prepared by mixing the sand with an oil content of 0-5% with respect to dry soil to match the field conditions. The investigations are carried out by varying the depth and the length of the contaminated sand layer and the type of oil contamination. A plain-strain elastoplastic theoretical model with an interface gap element between footing and the soil is carried out to verify the test results of the model. It is shown that the load-settlement behavior and ultimate bearing capacity of the footing can be drastically reduced by oil contamination. The bearing capacity is decreased and the settlement of the footing is increased with increasing the depth and the length of the contaminated sand layer. The agreement between observed and computed results is found to be reasonably good in terms of load-settlement behavior and effect of oil contamination on the bearing capacity ratio. A comparison between the model results and the prototype scale (B=1.0 m) results are also studied. © 2009 ASCE. Source


Ewais H.A.,King Abdulaziz University | Taha M.,National Taiwan University of Science and Technology | Salm H.N.,Al Tahadi University
Journal of Chemical and Engineering Data | Year: 2010

Ternary 1:1:1 complexes of Pd(II) with dipicolinic acid (DPA) or iminodiacetic acid (IDA) as primary ligands and some selected mono-and dicarboxylic amino acids (glycine, α-alanine, leucine, valine, phenylalanine, tryptophan, methionine, histadiene aspartic acid, and glutamic acid), aromatic carboxylic acids (salicylic and phthalic), and aliphatic carboxylic acids (succinic, oxalic, malic, maleic, malonic, and tartaric) as secondary ligands have been investigated by using the potentiometric technique at T = 30 °C and I = 0.1 mol·dm-3. The ternary complexes are formed in a stepwise mechanism. Confirmation of the ternary complexes in solution has been carried out using conductometric measurements. © 2010 American Chemical Society. Source

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