An-Najah University Journal for Research - A (Natural Sciences)

Permanent URI for this collection

https://hdl.handle.net/20.500.11888/812

Browse

Now showing 1 - 20 of 266

Occurrence of Pythium Species in Cultivated Soils in the West Bank and Gaza Strip: A Preliminary Report
(1986) Mohammed S. Ali-Shtayeh
The Pythium flora of 38 soils from different sections of the West Bank and Gaza Strip was determined using a selective agar medium and a surface - soil - dilution plating technique. A total of 23 species were recovered. Sixteen of these species possessed subglobose sporangia and/or hyphal swellings and constituted 92 % of the total number of Pythium propagules. The remaining species had filamentous or lobulate sporangia. Considerable differences in population levels in the different localities were found. The Nablus locality harboured the highest mean level of Pythium propagules followed by the localities in Jenin, Bethlehem, Jericho, Tulkarm, Ramallah, Gaza Strip, and Hebron. Solis in the different localities differed also in population levels and composition of species. Associations between Pythium population levels and soil factors and agricultural practices are discussed.
Photon Shadowing in Nuclei
(1986) Ghassan Saffarini
Photonuclear Shadowing is studied using the Glauber - generalized vector meson dominance approach. The calculation is performed using both diagonal and off - diagonal generalized vector dominance (GVMD) models. The results are compatible with experiments within the large systematic uncertainties of the available data.
Tinea Capitis in the Nablus Area
(1986) Hisham M. Arda
During 1972 - 1979 tinea capitis patients constituted 4.2% of all new dermatology patients clinically diagnosed at the outpatient skin clinic in Ittihad Hospital and at a private clinic in Nablus. About 78.6% of tinea capitis patients were from rural areas. 76.5% of them were under the age of 10 years. In a survey at primary schools in two villages, in a refugee camp and in the city of Nablus, the incidence of tinea capitis was found to be about 15% in the village schools, 3% in the camp and 1.8% in Nablus.
Homogeneous Catalysis of O-Silylation Reactions Using Tris (Acetylacetonato) Cobalt (III)
(1986) Hikmat S.Hilal
Tris (acetylacetonato) cobalt (III), (Co(acac)3), has been used to catalyze o-silylation reactions of R 3 Siff (R.z.Et,Et0) with R OH (Rt-Et, i-Pr, t-.Bu and C6Hj-). No reaction has been observed at room temperature, but the reaction is apparently enhanced when carried out at a higher temperature. The rate of the reaction varies with varying the concentration of the saline or the alcohol. Using different types of alcohols and silanes greatly affects the rate of the reaction. The rate of the reaction is affected by varying the concentration of the complex (Co(acaci6)).
Study of Changes in the Ground Water in Gaza Strip during the Last Twenty Years
(1986) M. Ashour
The inhabitants of the Gaza Strip depend heavily on underground resources for their water supplies. This is due, partly, to the scarcity of rain falls in that region and, also, to the limited number (three) of streams and the inadequate quantities of water which can be drawn from them. Chemical analysis of the water (for irrigation and domestic purposes) obtained from several wells and the comparison of the results, with those previously performed, on the same wells, showed, conclusively, that there exist a gradual change in the quality of water attainable from these wells. This has been attributed, to the intrusion of the Mediterranean salty water into the main aquifer (Plio-Pleistocene aquifer) of the area.
الكشف عن الذرات المفردة باستعمال أشعة الليزر
(1986) Munir Hasan Nayfeh
M.R.H. A New Era in Magnetic Head Design
(1986) Mazen R. Husni
The conventional method for reading/writing information from/on a magnetic media (e.g. magnetic tapes in audio and video recorders, computers etc.) uses what is called an inductive head. This consists of several turns of enemelled wire, wound on a specially prepared former as shown in Fig.1. To write (record) information on the magnetic tape, a modulated current signal is injected into the coil. The current treats (induces) a magnetic field at the free ends of the former (poles) which in turn aligns the magnetic particles deposited on the tape, subsequently producing a record of the injected signal. To retrieve the information (i.e. playback the recorded signals) the prerecorded tape is swiped across the poles of the inductive head. In this case the reverse of the write cycle occurs i.e. the magnetic field from the tape influence the former in such a manner as to cause a current flow through the coil having the same form as the recorded signal. A major disadvantage of this type of head is its speed dependence. Since the head senses the rate of change of field, d?/dt (and not the field itself ? its output becomes greatly dependent' on the speed of the tape. Therefore, in tape system, and using an inductive head, it becomes necessary to use some form of electronic equalization in order to correct errors in the signal, resulting from any variations in the speed of the tape. In addition, because of their bulkiness, they become difficult to implement in applications where high packing densities (video tapes) or multi-track system (computer tapes) are used. A new generation of heads have been developed. The heads use the magneto-resistive effect for the read operation and a simplified inductive approach for the write operation.
Two Methods for the Evaluation of Six Disinfectants Using Pseudomonas Aeruginosa and Serratia Marcescens as the Test Organisms
(1986) Yahya R. Faydi
A total of 50 isolates of Pseudomonas aeruginosa and 6 isolates of Serratia Marcescens from various clinical specimens were used in this study. The action of various commercial disinfectants on these isolates was studied using the agar and broth dilution methods. All S. Marcescens strains were inhibited by. 0.15% 0-syl or 0.44% Savlon. While P. aeruginosa strains were inhibited by 0.3% 0-syl or 0.88% Savlon. Both organisms were inhibited by 0.65% Westaspet, 0.125% Phenol, 0.5% Acriflavin or 0.25% Micro - Bac.
Pollution Levels of Drinking Water in Nablus
(1987) H.S. Hilal; R. Salim; Z. Qattawi
Metal concentrations in drinking water used in Nablus have been studied. Samples from houses located in various districts of Nablus have been collected between Dec. 22, 1985, and Jan. 19, 1986, acidified and then analyzed for their metal content of the elements lead, copper, zinc, nickel, iron, manganese, calcium and magnesium using flame atomic absorption spectroscopy with an acetylene-air flame The results showed that the concentrations of lead, copper, nickel, iron and manganese were well below the safe limits. The concentrations of both zinc and magnesium were high but still below the maximum limit allowed in drinking water. The concentration of calcium was found always above the allowed limit. The effect of storing water in tanks (this is very common in Nablus) on the concentration of the above elements has been studied. The only effect found for storing water in tanks was a decrease in the concentration of zinc from water. No effect was found for using sun-heaters on the concentrations of the above elements in water.
Pyridylazo Compounds As Analytical Reagents: A Review
(1987)
A large number of 2-pyridylazo compounds have been proposed as reagents for the spectrophotometric determination of several metal ions. The application of 2-pyridylazo compounds for the determination of many metal ions is listed and several procedures are described to illustrate the fundamental conditions for the spectrophotometric determination of these metal ions.
Kinetic Study of the Complexation of Palladium (II) With 2-(5-Bromo-2-Pyridylazo)-5-Diethylaminophenol
(1987) Bassem F. Shraydeh
The kinetics of the complexation reaction of palladium with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) has been studied in the stability time at the optimum pH of 3.53 in presence of 50% ethanol. The effect of ionic strength and temperature on the reaction rate were reported. A mechanism has been postulated and the stability constants of the individual steps were determined. The Arrhenius and thermodynamic parameters were evaluated and discussed.
The Development of Rotylenchulus Reniformis and Tylenchulus Semipenetrans, on Grape Roots
(1987) S.A. Sultan
The results showed that the average numbers of eggs per an egg mass of R. Reniformis and T. Semipenetrans were 84 and 36 eggs, and the eggs hatched after 6 and 7 days respectively. The durations of the life cycle were 30 and 41 days, respectively. Life cycles were divided into migratory and sedentary phases. The migratory phase (soil phase) of R. reniformis was not parasitic and lasted for about 21 days; while that of T. semipenetrans was parasitic and lasted for about 31 days. The sedentary phase of both nematodes was parasitic and lasted for about 9 and 10 days for R. reniformis and T. semipenetrans respectively. Only the young females of R. reniformis were the infective stages; while all larval stages and young females of T. semipenetrans were able to penetrate root tissues.
Base Cleavage of Some Benzyl-Silicon and Tin Compounds in H2O-MeOH-Cyclodextrin Medium
(1987) Foad M. S. Mahmoud
The effects of oc - and f3- cyclodextrin (x - ,13- CD's) on the rates of base cleavage of 4 - CNC6 H4 SnMe3 ,3—CIC6 H4 CH2 MMe3 , 4 C1C6 H4 CH2— MMe3 and 3,5 - CL2 C6 H3 CH2 MMe3 with M = Si and Sn have been examined in H 2O - Me0H medium . oc - and 13-CD's accelerate the cleavage of the RSnMe3 compounds (R=3-0106 H4 CH2 , 4-0106 H4 CH2, and 3,5 - 01 2 C6H3 CH2 ) . There is no significant catalysis in the case of the corresponding silicon compounds.
The Susceptibility of Twelve Grape Cultivars to Meloidogyne Incognita Acrita, Rotylenchulus Reniformis and Tylenchulus Semipenetrans
(1987) S. A. Sultan
In this study the susceptibility of 5 American cultivars (Delight, Fiesta, Freedom, Harmony and Ruby), 3 Egyptian cultivars (Baladi, Bez-Alanza, and Fayumi) and 4 Palestinian cultivars (Al-Zeiny, Black-Zeiny, Beitony and Chamey) were tested for the three nematode species. The results indicated that, the twelve grape cultivars were different in their susceptibility to each nematode species. Black-Zeiny and Ruby sustained the highest population densities of all these nematode species, whereas freedom and Harmony cultivars supported the lowest number of all nematode species. Chamey and Zeiny were good hosts of M. incognita; Delight and Fiesta were good for both R. reniformis and T. semipenetrans. Beitony was a good host for both M. incognita and T. semipenetrans but a poor host for R. reniformis Baladi, Bez-Alanza and Fayumi were moderate hosts for all the three nematode species. The results also indicated that some of these cultivars could be considered resistant to all three nematode species (c.v Harmony), or immune to M. incognita but resistant to others (c.v. Freedom) or resistant to M. incognita only c.v. Fiesta).
Spectrophotometric Studies and Analytical Application of Cerium (III) and Thorium (IV) Chelates with Pyridine-2-Aldehyde-2-Pyridylhydrazone (PAPH)
(1987) Mohammad A. Hannoun
Ce (III) and Th (IV) reacts with pyridine-2—aldehyde-2—pyridylhydrazone in aqueous solutions containing 50 % ethanol at pH's 7.75 and 8.45 respectively. Beer's law is obeyed over the range 0.0-15.p.g and 0.0-18 ktg of cerium and thorium respectively. The proposed procedure is sensitive, since molar absorptivity is 2.56 x 10 4 and 3.60 X 10 4 1.mol -1 cm-1 for Ce (III) and Th (IV) respectively. The composition and stability of these complexes have been determined. The limitation of this procedure and the effect of other ions have been studied.
The Use of Transition-Metal Complexes as Catalysts in Tertiary Silanes Reactions with Unsaturated Organic Compounds and Alcohol: A Review
(1988) H. Hilal
This review deals with reactions of tertiary silanes R3SiH with unsaturated organic compounds (e.g. alkanes, dienes, alkynes, ketones, and aldehydes) and with alcohols R'OH, using transition- metal complexes as catalysts. Due to the bulk of relevant literature, special attention has been given to mechanistic aspects of the roles of the catalyst in the reaction. Main references which appeared in the period l960-1986, have been reviewed.
Pollution Levels of Drinking Water in Several Villages in Nablus Area and in the City of Hebron
(1988) H. Hilal; I. Khatib; R. Abu-El-Halawa; R. Salim; Z. Qattawi
Samples of drinking water were collected from several villages in Nablus area, and from the city of Hebron. The concentrations of lead, copper, nickel, manganese, iron, zinc, magnesium and calcium were determined in these samples using flame atomic absorption Spectroscopy. The obtained results were compared with the maximum allowed limit of concentration for each of these elements in drinking water.
The Role of Solvent on the Kinetics and Mechanism of the Hydrolysis of Salicylidene Benzoyl Hydrazone
(1988) Maher Abu-Eid
The effect of various solvents on the kinetics and mechanism of the hydrolysis of Salicylidene Benzoyl hydrazone (SBH) has been studied at five different temperatures (17-45 C) using U.V. and visible spectrophotometry. In both protic and aprotic solvents, the hydrolysis rates follow first order kinetics. The role of solvent on the reaction rate, thermodynamic parameters and mechanism have been reported and discussed.
Distribution of ABO Blood Groups and the Rh factor in Palestinians Living in the Northern Part of the West Bank
(1988) A. H. Hamdan; M.S. Ali-Shtayeh; Yahya R. Faydi
The ABO blood groups and the Rh factor were determined for 1308 Palestinian subjects living in the northern part of the West Bank, using Anti-A, Anti-B, and Anti-D sera. Group 0 was the most frequent blood group in these subjects (46%) followed by group A (36.7%), group B (137.) and group AB (3.7%). Of the examined subjects 90.4% were Rh and 66.5% of these were females.
A Detailed and Simplified Solution to Hydrodynamic Forces on a Submerged Tank Subject to Lateral Ground Excitation
(1988) A. H. Helou
The domain where a submerged vertical cylindrical tank exists is divided into two regions. Assuming irrational motion and an ideal fluid the Laplace s equations in both regions are solved by the method of separation of variables. The integral equation resulting from matching the potentials at the interface is solved numerically by the Galerkin method. It is shown that the mathematical labor is greatly reduced by dropping the surface effects and the results are in good agreement with those obtained by including surface effects albeit at higher values of excitation frequencies. The case of protruding cylinder is presented to further illustrate the simplicity of the solution.

Browse

Browsing An-Najah University Journal for Research - A (Natural Sciences) by Issue Date

Results Per Page

Sort Options