Showing papers by "Jordan University of Science and Technology published in 1992"
TL;DR: In this article, the authors present a method for calculating the damping and synchronizing torques in multimachine power systems, and apply it to evaluate the stability of interconnected power systems and weakly coupled and closely coupled machines.
Abstract: The authors present a method for calculating the damping and synchronizing torques in multimachine power systems. This method is applied to evaluate the damping and synchronizing torques in interconnected power systems, and weakly coupled and closely coupled machines for different operating conditions and machine parameters. The investigation is enhanced by modal analysis. It was found that both approaches, namely the damping and synchronizing torques and modal analysis, complement each other to provide insight into the stability of multimachine power systems. >
42 citations
TL;DR: Analysis of scale-up of the separation of hen egg-white proteins using Whatman DE92 anion-exchange cellulose shows column processes to be more efficient than batch in the adsorptive stage.
36 citations
TL;DR: ‘Micro‐Tom’ plants survived and continued fruit production at higher salinity levels despite reduced canopy growth, and fruit yield was highly correlated with total canopy and shoot area, but not with tissue osmotic or total water potential.
Abstract: The growth and production of miniature dwarf tomato selection Lycopersicon esculentum ’Micro‐Tom’ plants grown from seedling to harvest in solution batph culture’ at four different NaCl salinity levels (2.4 [control, no NaCl], 7.6, 12.8, or 18 dS‐m‐1 solution conductivities) was monitored. Incremental reductions in canopy extent and shoot area of ‘Micro‐Tom’ were observed with increasing solution NaCl level. Root growth and shoot height were somewhat less responsive to imposed salinity. Fruit number, fruit size, and leaf tissue osmotic potential decreased as NaCl concentration increased. Fruit yield was highly correlated with total canopy and shoot area, but not with tissue osmotic or total water potential. ‘Micro‐Tom’ plants survived and continued fruit production at higher salinity levels despite reduced canopy growth. Treatment effects on vegetative growth and fruit production became more pronounced later in the growth cycle.
33 citations
TL;DR: In this article, the minimum spout-fluidized flow rate in cylindrical columns was investigated for six different materials, spouted and spoutfluidised with air in a column of square cross-section, using nozzles of five different sizes.
33 citations
TL;DR: Sera of 699 individuals, aged between 5-24 years, from the Irbid area, Jordan, were tested for Toxocara canis antibodies using an ELISA-IgG test and the trend of prevalence in relation to age was different according to sex.
Abstract: Sera of 699 individuals, aged between 5-24 years, from the Irbid area, Jordan, were tested for Toxocara canis antibodies using an ELISA-IgG test. Crude prevalence was 10.9% (76 of 699) but age-adjusted prevalence was 14.3%. The highest prevalence was observed in females aged 5-9 years, 23.3% (7 of 30), and males of 15-19 years of age, 19.5% (16 of 82). The lowest prevalence was observed in females aged 20-25 years, 5.2% (8 of 155). Significant differences (P < 0.05) between the prevalences of the toxocaral antibodies in males and females were observed in the age groups 5-9, 15-19 and 20-24 years. The trend of prevalence in relation to age was different according to sex.
31 citations
TL;DR: Microbiological studies indicated decreased activity of norfloxacin in the presence of metal ions and the formation of a complex with Al 3+ enhanced the water solubility of the drug.
31 citations
TL;DR: In this paper, a non-linear electromechanical model is presented to describe the dynamical behavior of overhead cranes, taking into account the nonlinear dependence of the load sway on transients of driving motors during voltage disturbances and start-ups.
Abstract: A non-linear electromechanical model describing the dynamical behaviour of overhead cranes is presented. The model takes into consideration the non-linear dependence of the load sway on transients of driving motors during voltage disturbances and start-ups. This is extremely useful in practice since load sway control schemes normally utilize input voltages as control variables. The mechanical subsystem within the model is that of the load sway and has the swing angles and their derivatives as state variables. Each of the two driving motors, namely, the girder motor and the trolley motor, is represented by the classical fifth-order model of induction machines where electrical transients as well as mechanical transients are considered. The model is linearized using Taylor series expansion around a normal operating point. A numerical example is presented to illustrate the usefulness of the results.
29 citations
01 Jan 1992
TL;DR: The brine shrimp lethality bioassay revealed that 25 of these extracts were toxic with LC50 values in the range of 1.7—579 µg/ml (ppm), and aflatoxin B, was detected only in Brassica nigra and Nigella sativa.
Abstract: A total of 46 plants were tested for direct mutagenic activity using Salmonella typhimurium strains TA98 and TA102. The most active extracts were derived from Coriandrum sativum, Myristica fragrans, Eugenia caryophyllus and Zingiber officinale. Intermediate activity was shown with Carum carvi, Foeniculum vulgare, Brassica nigra. Nigella sativa. Lawsonia inermis. Mentha piperita. Thymus capitatus, Rheum officinale. Curcuma domestica and Cinnamomum zeylanicum. Weak mutagenicity was exhibited by six additional plants, and the remaining plants tested were nonmutagenic. Mycotoxins (aflatoxin B1 and B2) were monitored using the same 46 herbs; aflatoxin B, was detected only in Brassica nigra and Nigella sativa. The brine shrimp lethality bioassay revealed that 25 of these extracts were toxic with LC50 values in the range of 1.7—579 µg/ml (ppm).
27 citations
TL;DR: The crystal structure of the title compound has been determined as mentioned in this paper, and the structure was solved by direct methods and refined with 1970 reflections to a finalR value of 0.057.
Abstract: The crystal structure of the title compound has been determined. The crystals are monoclinic:P21n(NO. 14),a=12.279(7),b=8.223(1),c=15.504(7)A,β=96.16(2)°,Vc=1556(2)A3,Z=4,Dx=1.511 g cm−3,λ=(MoKα)=0.71069 A. The structure was solved by direct methods and refined with 1970 reflections to a finalR value of 0.057. Analytical, mass, spectral, and physicochemical data are also reported.
24 citations
Journal Article•
TL;DR: The results suggest that Op18 phosphorylation is mediated by protein kinase C activation as an early event in T cell activation through the T cell receptor.
Abstract: Op18 is a highly conserved major cytosolic phosphoprotein that has been implicated in signal transduction in a wide variety of cell types Freshly isolated peripheral blood lymphocytes (PBL) constitutively express low levels of mostly unphosphorylated Op18 After mitogenic stimulation of PBL, Op18 synthesis is induced at a time when cells are entering S-phase In this study, we have examined the phosphorylation of Op18 in freshly isolated PBL after activation of the T cell receptor by OKT3 Quantitative analysis of Op18 phosphorylation was undertaken by metabolic labeling with 32Pi and PhosphorImager analysis of two-dimensional gels After 10 or 15 min of activation by OKT3, one of the three major phosphorylated forms of Op18, designated Op18c, increased approximately 10-fold, which represented a most pronounced change among a large number of phosphoproteins analyzed In time course experiments, increased Op18 phosphorylation to yield Op18c was observed as early as 2 min Continued OKT3-induced activation for 20 to 72 h resulted in a further increase in phosphorylated Op18 forms, which paralleled new Op18 synthesis and occurred at a time when cells were entering S-phase, as determined by [3H]-thymidine incorporation Inhibitors of lymphoid proliferation, cyclosporin A and RPM, had no effect on early (less than 15 min) phosphorylation Addition of calphostin C, a specific inhibitor of protein kinase C, 1 min prior to stimulation of resting T cells with OKT3 completely inhibited further phosphorylation of Op18 Incubation of PBL with calphostin C for 75 min decreased constitutive levels of phosphorylated Op18 In contrast, inhibition of cyclic nucleotide-dependent protein kinases with HA1004 had no effect on Op18 phosphorylation Activation of cAMP-dependent protein kinase with Forskolin or 8Br-cAMP did not increase Op18 phosphorylation Our results suggest that Op18 phosphorylation is mediated by protein kinase C activation as an early event in T cell activation through the T cell receptor
24 citations
TL;DR: A study of 260 Jordanians who became blind or visually impaired before the age of 15 years showed the dominant effects of genetically determined causes in two generations, and there was a statistically significant change in the overall pattern and pattern of blindness between the two generations.
Abstract: A study of 260 Jordanians who became blind or visually impaired (according to World Health Organization standards) before the age of 15 years showed the dominant effects of genetically determined causes in two generations. Genetic causes were responsible for the visual impairment in 122 (77.7%) of 157 subjects in the group born after 1970 and for 69 (67%) of 103 in the group born before 1970. There was a statistically significant change in the overall pattern (genetic and acquired causes) of blindness between the two generations, and there was also a significant change in the pattern of acquired blindness alone. A decrease in corneal infections leading to blindness or visual disability in the younger generation was accompanied by an increase of trauma in the same age group. Parental consanguinity in those with genetically determined causes of visual impairment was high compared with those with nongenetic causes (79% vs 33.3%, P < .05). The autosomal recessive mode of inheritance was the most common pattern encountered (53.9%).
TL;DR: In this paper, a finite-difference scheme was proposed to solve the transient laminar forced convection problem in the entry region of a concentric annulus with sumultaneously developing hydrodynamic and thermal boundary layers.
TL;DR: In this paper, the effect of early overloading of concrete on its strength development was investigated, and the results indicated that loading concrete beyond 8 hours after casting, up to 90% of its compressive strenght has no effect on later strength development.
TL;DR: In this article, the effect of nonlinearities in clastomeric material dampers used to quiet torsional oscillations of internal-combustion engines shafts is investigated.
Abstract: The effect of non-linearities in clastomeric-material dampers used to quiet torsional oscillations of internal-combustion engines shafts is investigated. The method of multiple scales is used to solve the equations for the case of primary resonance. Steady-state solutions are obtained and their stability examined. A relationship that relates the elastomer properdes (for stable solutions) and other system parameters is found. The steady-state response shows a softening behavior of the system although the actual material non-linearity is of the hardening type.
TL;DR: Female college students needed guidance in selecting nutrient dense foods and attention in nutrition education programmes should be directed toward the individual student rather than the group.
Abstract: This study assessed the nutrient intakes of 203 female college students, aged 20-31 years, mean 21 years. Results from computer analysis of 3-day food records showed that, on the basis of group means, two thirds of Recommmended Daily Allowance (RDAs) was met for all nutrients except iron, zinc, folacin and vitamin D. Nutrient intake and RDAs showed no significant differences related to marital status with the exception of vitamin D and manganese (p < 0.05). The indexes of Nutritional Quality indicated that, on average, diets of the students met or exceeded nutrient density allowance for protein, vitamin A, vitamin C, thiamin, riboflavin, niacin, vitamin B6 and phosphorus.Nutrients for which the average female student consumption was below recommended standards on a calorie basis, were carbohydrates, fat, vitamin D, folacin, calcium, iron, zinc and sodium. The diets were limited in fibre, high in sugar, high in caffeine and slightly above recommendations in cholesterol.Female college students needed guidan...
TL;DR: In this article, the authors proposed a star topology for multihop lightwave networks in which the conventional N*N passive star coupler is replaced by fixed wavelength division multiplexed (WDM) cross connects.
Abstract: The authors propose a star topology for multihop lightwave networks in which the conventional N*N passive star coupler is replaced by fixed wavelength division multiplexed (WDM) cross connects. The proposed topology overcomes three major limitations of the conventional star topology. First, it reduces the number of wavelengths needed in a (p,k) ShuffleNet from kp/sup k+1/ wavelengths in the conventional topology to p wavelengths in the proposed one. Second, the signal power loss due to the 1/N power splitting at the star coupler no longer exists in the WDM cross connects and, therefore, the restriction on the supported number of users by the star network is alleviated. Third, it completely eliminates the need for wavelength filtering at the input to the receivers as is the case in the conventional star topology. >
TL;DR: Two methods are described for the simultaneous determination of theophylline and guaiphenesin in combined pharmaceutical dosage forms based on third-derivative ultraviolet spectrophotometry and high-performance liquid chromatography.
Abstract: Two methods are described for the simultaneous determination of theophylline and guaiphenesin in combined pharmaceutical dosage forms. The first method depends on third-derivative ultraviolet spectrophotometry, with the zero crossing technique of measurement. Third-derivative amplitudes at 222 and 278 nm were selected for the assay of guaiphenesin and theophylline, respectively. The second method is based on high-performance liquid chromatography on a reversed-phase column using a mobile phase of 0.01 mol dm–3 sodium dihydrogen phosphate–methanol–acetonitrile (8 + 2 + 1)(pH 5.5) with detection at 245 nm. Both methods showed good linearity, precision and reproducibility. The proposed methods were successfully applied to the determination of these drugs in laboratory-prepared mixtures and in capsules or elixir.
TL;DR: In this article, the authors examined the release of diclofenac sodium from ethylcellulose (EC) microcapsules made up of different drug to polymer ratios.
Abstract: This work examines the release of diclofenac sodium from ethylcellulose (EC) microcapsules made up of different drug to polymer ratios. The release process was found to follow the Higuchi square root equation and not the zero-order or first order equations. However, for drug to polymer ratio of 1:1, a critical time (θ) was reached beyond which the release rate was lower than that predicted on the basis of the Higuchi square root equation. Dissolution experiments in 0.1N HCL revealed that less than 1.5% of the encapsulated drug was released in 6 h. This finding indicates the suitability of the EC microcapsules for enteric-coated preparations. The in vitro release of diclofenac sodium from microcapsules of different drug to polymer ratios was compared with that from a commercial sustained-release product. A distinct similarity between the release profile of the commercial product with that obtained for the 1:2 drug to polymer microcapsules was noted. The in vivo work included determination of the se...
Patent•
20 May 1992TL;DR: In this article, the interstitial point is generated by adding the N-bit-shifted difference of a first and second point data and the one-bit shifted difference of the fourth and third point data.
Abstract: A method and apparatus generates non-linearly interpolated point data of a graphic display. At least four graphic point data are retained in a memory and are arithmetically processed to generate an interstitial point data between an interval of the graphic point data. The interstitial point is generated by adding the N-bit-shifted difference of a first and second point data and the N-bit shifted difference of a fourth and third point data and the one-bit-shifted summation of the second and third point data.
TL;DR: In this article, an accurate, sensitive and precise derivative ultraviolet Spectrophotometric and high-performance liquid chromatographic (HPLC) methods are described for the simultaneous determination of three natural methyl xanthines (theobromine, theophylline and caffeine) in various food products.
Abstract: Accurate, sensitive and precise derivative ultraviolet Spectrophotometric and high-performance liquid chromatographic (HPLC) methods are described for the simultaneous determination of three natural methyl xanthines (theobromine, theophylline and caffeine) in various food products. The derivative UV-spectro-photometry, with zero crrosing technique of measurement was selected for determination of theobromine and theophylline. First-derivative procedure (D1) was adopted for theobromine determination in the presence of theophylline and caffeine; and second-derivative procedure (D2) was adopted for theophylline determination in the presence of theobromine and caffeine. Caffeine was determined by compensation method using the zero order spectrophotometry. The second method was based on HPLC on a reversed phase column, using a mobile phase of 0.01 M sodium acetate solution: acetonitrile (85:15%) at PH 4.0 with detection at 272 nm. Both methods show good linearity, precision and reproducibility. The dev...
Journal Article•
TL;DR: Twenty-two infants suffering from infantile hypertrophic pyloric stenosis underwent Ramstedt's pyloromyotomy using circumumbilical incision, which gives access that is almost comparable to other incisions without a significant increase in the morbidity rate.
Abstract: Twenty-two infants suffering from infantile hypertrophic pyloric stenosis underwent Ramstedt's pyloromyotomy using circumumbilical incision. There was no difficulty in delivering the pylorus out of the incision. Three patients developed wound infection, one patient developed wound dehiscence at the fascial plane and one patient developed stitch sinus. No incisional hernias were noted after a follow-up period ranging from 2 months to 4 years (mean 27 months). All scars were neat except that of the patient who developed wound dehiscence at the fascial plane and another who developed stitch sinus. This incision is cosmetic and gives access that is almost comparable to other incisions without a significant increase in the morbidity rate.
TL;DR: It is demonstrated that propofol enjoys a considerable degree of anticonvulsant activity in the rabbit that is greater than that of thiopental at doses ranging from 2.5 to 10mg/kg and equipotent with diazepam at the 10 mg/kg dose.
14 Jun 1992
TL;DR: A star topology for multihop lightwave networks in which the conventional N*N passive star coupler is replaced by fixed wavelength division multiplexing (WDM) cross-connects is proposed, which reduces the number of wavelengths needed in a (p,k) ShuffleNet from kp/sup k+1/ wavelengths to p wavelengths.
Abstract: The authors propose a star topology for multihop lightwave networks in which the conventional N*N passive star coupler is replaced by fixed wavelength division multiplexing (WDM) cross-connects. The proposed topology overcomes three major limitations of the conventional star topology. First, it reduces the number of wavelengths needed in a (p,k) ShuffleNet from kp/sup k+1/ wavelengths in the conventional topology to p wavelengths in the proposed one. Second, the signal power loss due to the 1/N power splitting at the star coupler no longer exists in the WDM cross-connects and, therefore, the restriction on the supported number of users by the star network is alleviated. Third, it completely eliminates the need for wavelength filtering at the input to the receivers, as is the case in the conventional star topology. The use of 2*2 WDM lapped couplers as a cheap WDM cross-connect for a (2,k) ShuffleNet is investigated. A p*p star coupler followed by p fiber Fabry-Perot filters can be used as a p*p WDM cross-connect for a (p,k) ShuffleNet at the expense of using p/sup 2/ rather than p wavelengths. >
TL;DR: In this article, the authors proposed a novel technique for constructing large passive star couplers with gain using high-power erbium-doped fiber (EDF) amplifiers.
Abstract: The authors propose a novel technique for constructing large passive star couplers with gain using high-power erbium-doped fiber (EDF) amplifiers. In contrast to other proposed techniques where each output port of the coupler requires its own EDF amplifier, the proposed alternative requires few EDF amplifiers with sufficient output saturation power levels. When used in an FDM/WDM star network, the size of the coupler can be increased by a factor of m using m narrowband EDF amplifiers. Moreover, this alternative avoids coupling the pump-laser light through the star coupler itself, alleviating the requirement on designing large bandwidth couplers to accommodate the signal and the pump wavelengths. >
TL;DR: A selection index was developed and is based on SI, GI, days to heading, and filling period, and a number of LR and CR genotypes have been identified with high yield potential in El and above average yield in E2.
Abstract: The influence of drought stress on grain yield and developmental phases was studied in 132 landrace genotypes (LR) of durum wheat from Jordan. A number of old (OV) and improved (IV) durum wheat varieties, and F6 selections from crosses (CR) between LR and IV were included. A total of 320 genotypes were planted in an observation nursery, with two replicates, in a semiarid (El) and an arid (E2) environment. Stress susceptibility (SI) and growth inhibition (GI) indices were calculated for each entry, based on grain yield and plant height, respectively. Potential yield (Yd), in El and yield under stress (Yd) in E2 were significantly correlated (r = 0.227; P = 0.02); however, the genotype x environment interaction was significant. IV genotypes had the highest Yd in El (3562.9 kg ha-1), but not in E2 (Yd=893.6 kg ha-1). LR genotypes had a lower Yd than IV genotypes in El (2736.5 kg ha -1) and a higher Yd in E2 (923.3 kgha-1). The highest variability for grain yield in both El and E2 was displayed by CR genotypes. SI was positively correlated with Yd in El (r = 0.745; P = 0.000) and negatively with Yd in E2 (r =–0.328; P = 0.001). Also, SI was significantly correlated with days to heading and filling period in both El and E2, and with days to maturity in El. CR genotypes differed in their SI estimate (0.915) from IV (1.068) and OV (1.026). Percent growth inhibition (GI) due to stress was highest for OV (48.8) and IV (46.3); it was intermediate (37.9) for CR and lowest (33.6) for LR genotypes. A number of LR and CR genotypes have been identified with high yield potential in El and above average yield in E2. A selection index was developed and is based on SI, GI, days to heading, and filling period.
Journal Article•
TL;DR: The main findings of this retrospective study are in direct accord with other series reported in the literature and are typical of those to be found in large and comparable general community hospitals in Jordan.
Abstract: This retrospective study covers the authors' experience over five years of 1,722 primary hernia repairs in 1,722 patients of all ages. An analysis of some epidemiological features is presented and discussed. Inguinal hernia was by far the commonest variety accounting for more than 84% of the total series. Regardless of sex and type of hernia, 60% of all hernias were right-sided while not more than 5% were bilateral. The male to female ratio for the entire series was 4.3:1 and 8.2:1 for the inguinal hernia group. The main findings of this retrospective study are in direct accord with other series reported in the literature. Furthermore, we suspect our results are typical of those to be found in large and comparable general community hospitals in Jordan.
TL;DR: The association between acetylator status and IDDM in Jordanians, which agrees with that reported for the Saudi Arabian population, is the reverse of what is found in European populations.
Abstract: The acetylator phenotype was determined in 31 insulin-dependent (IDDM) and 110 noninsulin-dependent (NIDDM) Jordanian diabetics, and was compared to that of 160 healthy volunteers of the same ethnic group. Dapsone was used as the test drug. The rapid acetylator phenotype was slightly less frequent in IDDM and slightly more frequent in NIDDM. Neither of the differences was significant. When acetylator status in the two types of diabetes mellitus was compared, there was a significant difference among the two groups. Patients with IDDM had a higher percentage of the slow acetylator phenotype when compared to NIDDM patients. The association between acetylator status and IDDM in Jordanians, which agrees with that reported for the Saudi Arabian population, is the reverse of what is found in European populations. The results demonstrate ethnic differences in acetylator status among IDDM patients.
TL;DR: It was concluded that the beta-angle is a more accurate reflection of hip pathology in the newborn than the alpha-angle, which represents the cartilaginous roof of the acetabulum, which is soft and malleable, and reflects immediately any change in the position of the femoral head.
Abstract: In a screening program, 4438 newborns were examined sonographically and clinically in the first 12 hours after birth for congenital hip dysplasia. Seventy-three hips in 54 newborns were dislocated, as evidenced by positive Ortolani's signs. According to Graf's classification, all 73 hips should be Type IIC or worse, with Angle alpha less than 50 degrees and Angle beta for Type IIC of 72 degrees-77 degrees, and for Types D, III, and IV, greater than 77 degrees. Sonographic examination of the 73 hips according to Graf's criteria showed that only 16 hips were decentring and eccentric, confirming the clinical diagnosis, and the results were consistent with Graf's conclusion because their alpha-angles were less than 50 degrees and beta was greater than 77 degrees. In the remaining 57 hips, there was a disparity between alpha-angles and beta-angles. Judging by Angle alpha, these hips were of Types IB and IIA because their Angle alpha averaged 60.8 degrees (range, 51 degrees-74 degrees). Judging by Angle beta, these hips were decentring Type D or eccentric Type IIIA because their beta-angle averaged 91.3 degrees (range, 78 degrees-110 degrees). Because these 57 hips were dislocated clinically (positive Ortolani's sign) it was concluded that the beta-angle is a more accurate reflection of hip pathology in the newborn than the alpha-angle. It represents the cartilaginous roof of the acetabulum, which is soft and malleable, and reflects immediately any change in the position of the femoral head. Angle alpha, however, represents the hard bony roof, and any change in the position of the femoral head is not reflected immediately on it, because bony changes take longer to be seen or evidenced.