Vol. 14 Issue 2
Abdullah Shanableh
Adenosine triphosphate (ATP), a biochemical compound detected only in living cells, and oxygen uptake rate (OUR) were used to characterize the viability and metabolic activity of activated sludge microorganisms in batch and continuous flow systems operated at three sludge ages: θc= 2.5 days; θc= 5 days; and θc= 10 days. OUR responded rapidly to substrate addition to acclimated and starved microorganisms and indicated the cell's metabolic activity, while ATP remained relatively unchanged and reflected the concentration of viable biomass. A maximum viability of 100 percent defined at the minimum sludge age (θcM) estimated to be approximately 1.9 days. The viability of activated sludge solids decreased as the sludge age increased and was estimated to be, relative to the assumed viability at the minimum sludge age: 75 percent at θc=2.5 days; 45 percent at θc= 5 days; and 25 percent at θc= 10 days. ATP and OUR, combined with total suspended solids (TSS) and volatile suspended solids (VSS), should enhance the operation and control of activated sludge systems.
Ali Ayman A. Kamel
Anhydrite deposits either as weathering products or original sediments are found, over huge gypsum bodies in the Ras Malaab area near the Gulf of Suez, Egypt. Anhydrite can be converted to a useful building material by partially transforming the anhydrite into gypsum using chemical activators. The used activators are: ZnSO4, K2SO4 and MnSO4.
The Physico-mechanical properties of hardened natural anhydrite such as dry and wet compressive strength, bulk density, water absorption and apparent porosity are discussed. The results show that the addition of 3% MnSO4 gives the highest values of dry (~175 kg/cm2) and wet compressive strength values (~100 kg/cm2). These increase of activators percentage leads to the decrease of both water absorption and apparent porosity values.
X-ray diffraction analysis (XRD) is used to detect the percentage of transformed gypsum. A polarizing microscope was used to describe the micro-structure, cleavage planes, crystal structure and the new phases which were confirmed by scanning electron microscope (SEM).
Many factors were found to control the gypsification process such as type and percentage of activators, time of curing, difference in potentiality and electronegativity, in addition to the position of the elements of activators in the periodic table.
A.F. Ahmed, M.M. El-Mahallawi and M.S. Abdel Ghani
Umm Anab granitic pluton has an inhomogeneous composition which varies from quartz-monzodiorite, granodiorite to monzogranite. The former two varieties have strong trondhjemitic affinities. Similar to most trondhjemites, they display high soda, low potash and lime, comparable FeO, MgO, FeO/MgO and K2O/Na2O and are commonly corundum normative. The complete monzodiorite, granodiorite, monzogranite suite exhibits calc-alkaline fractionation trend with some transitional trondhjemite tendencies. These geochemical aspects characterize the Proterozoic active continental margins, that apparently related to subduction.
The REE geochemical characteristics of Umm Anab granitoids are interpreted to have been produced by partial melting of amphibolite, leaving residues consisting mainly of hornblende.
Many lines of evidence suggest that Umm Anab granitoids are interrelated by crystal fractionation. Albite and antiperthite fractionation can explain some of the scatter in the trondhjemitic varieties which has been noticed within many trondhjemitic suites and was interpreted as a primary magmatic feature
M. Hamed and D. Esmail
The main parameters of transient phenomena in a line are analyzed. Both attenuation factor and propagation coefficient are investigated in the time domain for transient as well as for steady-state operation. A theoretical base for the proposed model is presented. The insulation-level dependence for overhead transmission lines is discussed for both transmission and distribution systems. The margin of this dependence is deduced according to the geometrical dimensions of conductors. Both capacitive and inductive compensation are inserted. The proposed algorithm reduces the computational time due to its simplicity even in lines with compensation. The dependence of the rate of rise of front voltage on series and parallel compensation is considered. The rate of rise of front voltage (RRFV) along a typical 750 kV 400 km line is evaluated. The dependence of the maximum value of RRFV on either the series-compensation rating or the shunt compensation at the receiving end of a typical 750 kV transmission line with different lengths is discussed
Ahmad Ayesh, Jehad Abu-Shama and Riyad N. Ahmad-Bitar
This is to report on the structural and Photoluminescence (PL) studies of thin films of CdTe on glass or CdS (0.25 µm) /glass substrates which were prepared by the physical evaporation method. The CdS/ glass substrate temperature was the variable parameter in this experiment. The effect of chemical and heat processing and substrate temperature on the structural and the electro-optical properties were analyzed. X-ray diffraction results showed a preferential growth in the (III) direction of treated and untreated films.
The Scanning Electron Microscopy results showed considerable grain growth with chemical treatment, and little effect on grain size with heat treatment only. The cycling of the chemical and heat treatment resulted in more growth in grain size. Photoluminescence (PL) spectra, in the region 1.6-1.2 eV, were taken for untreated and treated samples at 12K. All untreated samples showed undetectable PL spectra. The heat treated samples showed a very weak PL relative to the chemically treated samples. Cycling the chemical and heat processing resulted in more intense PL spectra and resolved longitudinal-optical phonon replicas indicative of an improvement in film crystallinity. The PL spectra of samples with increasing substrate temperature showed a substantial decrease in intensity with a shift of the maximum emission towards lower energy. This was attributed to diffusion of sulphur in CdTe. The PL spectra, taken for chemically treated samples from the front excited surface and the junction excited surface are of similar intensity and of approximately similar structure. This was evidence of the penetration of the chemical/heat treatment deep in the whole film.
A.S. Abu Ruwaida, W.N. Sawaya, Z.H. Baroon, M. Murad and W.R. Terry
Temperatures in display refrigerators of 42 food outlets were monitored to determine the shelf life of chilled poultry meat in Kuwait. Temperature fluctuations were also measured in 15 food outlets. Data showed that market storage temperatures were high averaging 8-10°C in more than 50% of the outlets surveyed and the temperature fluctuation in display refrigerators ranged between 1 and 6°C. Data on the shelf life of chilled poultry meat stored under simulated market storage temperatures showed that the spoilage rate was directly proportional to the storage temperature and the storage period. The shelf life after processing was about 7, 5 and 4 d at 4, 7 and 9°C, respectively. Incipient spoilage was first observed when the log count of spoilage reached >7.2 CFU/ml rinse. This was accompanied by changes in organoleptic characteristics (e.g., poor appearance, off-odors, slime formation and discoloration), increased values of total volatile nitrogen compounds, free fatty acids and decreased values of extract release volume. Data also showed high initial counts of E.coli and coliforms, indicating poor sanitation during slaughtering. As for food poisoning microorganisms, 60-80% of the samples tested positive for Salmonella, whereas Campylobacter was detected in all samples. The initial log count of Staphylococcus aureus was 3.4 CFU/ml. This count did not increase substantially during storage at 4-7°C, but increased rapidly to >4.4 CFU/ml after 3 d of storage at 9°C
Suad Al-Hooti, Jiwan S. Sidhu, Hanan Al-Amiri, Jamla Al-Otaibi and Hussain Qabazard
A variety of value-added processed products of acceptable quality were prepared in the laboratory from five different date fruit cultivars being grown in the United Arab Emirates. All of the processed products were free from aerobes except for the pickle-in-oil and chutney samples which had very low total plate counts. No molds, coliforms or members of the enterobacteriaceae were detented in any of these products. Among all the products prepared, dates-in-syrup, jam and butter were found to be the most acceptable to the panelists and thus may have commercial potential. All these processed date products had good shelf lives when stored at room temperature.
Ali M. Alsuhaibani
The seasonal abundance of two cereal aphids, Rhopalosiphum padi (L.) and Schizaphis graminum (Rondani) on twelve elite wheat lines were investigated. All wheat lines were infested by both aphid species. The population densities of R. Padi were much higher on all tested wheat lines than those of S. graminum. The number of the latter were lower on Durum than on Bread wheat lines and the opposite was true with the former. Wheat cultivar, West Bread was significantly less susceptible to R. Padi than L 891 and L 893 bread lines. Also, durum line L 18 is significantly less susceptible to infestation by the former insect than L 894. It is preferable to choose early maturing wheat varieties to avoid the build up of high numbers of aphids.
Fahad Al-Hemaid and Jacob Thomas
Tribulus, a highly polymorphic genus, includes many intermediate forms. Taxonomy of these taxa, mostly found in the same population has been studied over a wide range and a number of problematical species is discussed to resolve which of these merit taxonomic recognition. Five new combinations are proposed and the reasons for dropping the status of a few specific epithets, including amanense Hosni, to the level of synonyms are discussed in detail. Of the taxa described, T. rajasthanensis Bhandari and Sharma (1977) is reported for the first time from the Arabian Peninsula.
A.S. Hajar, M.A. Zidan and H.S. Al-Zahrani
The effect of different salinity levels (up to 300 mM NaCl) on germination, growth and some metabolic parameters of black cumin (Nigella sativa L.) was studied. The plant exhibited a good tolerance to salinity up to 150 mM during germination. But however, fresh and dry weight of shoot and root, Photosynthetic Pigments and leaf area were decreased when treatments were greater than 150 mM. Soluble and insoluble carbohydrates and proline contents increased with the increasing NaCl concentrations, whereas amino acids- free proline were reduced. Soluble protein was unaffected under all salinity levels, except in case of roots where it was decreased. Insoluble protein was decreased by increasing salinity. These results may lead to the suggestion that, black cumin is a salt tolerant plant and may be considered a glycophyte.