QScience Connect - Volume 2013, Issue 1

In this paper an inhomogeneous beam with a damping distributed along the length is considered. The beam is clamped at both ends and is assumed to vibrate in a transverse direction only. The total energy of the system at any time t is estimated. Finally, an explicit form of exponential energy decay is obtained. Hence, the uniform stabilization of the system is achieved.

Background: The demography of Copts in Egypt is subject to an intense debate in the context of a dearth of analytical studies on this community. Our objective was to estimate the size of the Coptic community in Egypt, map its geographical clustering, and describe demographic, socioeconomic, and health-associated indicators. Methods: We conducted descriptive and Kulldorff spatial scan statistics analyses using the 2008 Egypt Demographic and Health Survey (EDHS) data. We also used chi-square trend analysis and earlier EDHS data to examine the temporal trend in the proportion of Copts. Results: The proportion of Copts in the 15–59 years population was 5.1% (95% confidence interval (CI): 4.6%–5.5%). This translates to 4,274,145 (95% CI: 3,855,111–4,609,372) Copts. We identified three main clusters of Copts: Minya-Assuit cluster (17.6%), Assuit-Souhag cluster (15.1%) and the metropolitan Cairo cluster (9.4%). The proportion of Copts was stable since 1988 (P = 0.11). Copts had higher educational attainment (P = 0.002), and a wealth index quintiles distribution skewed towards the rich (P < 0.001). Copts also had stronger representation in white collar job types, but limited representation in security agencies. The majority of demographic, socioeconomic and health indicators were similar among Copts and Muslims. Conclusions: One in every 20 Egyptians is a Copt, a proportion smaller than commonly circulated in the scholarly literature and public sphere. Despite some identified disparities, our study indicates a well-integrated Egyptian society regardless of religious affiliation. Our study provides evidence to inform the ongoing debate on the status of Copts in Egypt.

In this paper, the differential equation of a vertically falling non-spherical particle in incompressible Newtonian media is solved by homotopy analysis method (HAM). The results are analyzed using graphs and comparison tables.

The (G′/G, 1/G)-expansion method is one of the most direct and effective methods for obtaining exact traveling wave solutions of nonlinear partial differential equations (PDEs). In this paper, we construct exact travelling wave solutions of nonlinear evolution equations in mathematical physics via generalized Zakharov-Kuznetsov (ZK), modified Zakharov-Kuznetsov and Sharma–Tasso–Olver (STO) equations by (G′/G, 1/G)-expansion method, where satisfies the auxiliary ordinary differential equation (ODE) ; λ and μ are arbitrary constants.

As part of the biodiversity surveys conducted by the Department of Biodiversity at the Qatar Environment and Energy Research Institute (QEERI), we can report the presence of Scaurus puncticollis Solier, 1838 in Qatar, and confirm the first record for the tribe Scaurini Billberg, 1820 in the country. We found two living specimens and remains of a third one distributed over the year (February, April and October) in three different locations of the Al Rayyan Municipality in Qatar. These findings reveal that the fauna of darkling beetles of Qatar is, despite previous efforts, still underestimated. To document and report the actual Biodiversity Heritage of Qatar, new exhaustive field biodiversity surveys should be conducted to complete the catalogue of Tenebrionoidae for the State of Qatar.

We present a geometric argument that explains why some systems having vanishing largest Lyapunov exponent have underlying dynamic aspects which can be effectively described by the Tsallis entropy. We rely on a comparison of the generalised additivity of the Tsallis entropy versus the ordinary additivity of the BGS entropy. We translate this comparison, in metric terms, by using an effective hyperbolic metric on the configuration/phase space for the Tsallis entropy versus the Euclidean one in the case of the BGS entropy. Solving the Jacobi equation for such hyperbolic metrics effectively sets the largest Lyapunov exponent computed, with respect to the corresponding Euclidean metric, to zero. This conclusion is in agreement with all currently known results on systems that have a simple asymptotic behaviour, and are described by the Tsallis entropy.

The equations of generalized thermoelastic diffusion with four relaxation times are given. The variational principle is derived. Using Laplace transforms, a uniqueness theorem for these equations is proved. Also, a reciprocity theorem is obtained.

We report the discovery of a gecko species, the Persian leaf-toed gecko Hemidactylus persicus Anderson, 1872 (Gekkonidae) in Qatar, found on Halul Island. According to the Qatar National Biodiversity Surveys and the available international literature H. persicus was not previously recorded in Qatar. Its known range covers the north east of the Arabian Peninsula, Bahrain, the United Arab Emirates, and south western Asia. Our findings bridge the current geographic gap in the known distribution of the species from Saudi Arabia to Asia. We believe that the species could also be present in the Qatar peninsula. A thorough field survey is needed in order to map the range of this species in the State of Qatar.

Ground Granulated Blast Furnace Slag (GGBFS) is a byproduct in the manufacture of pig iron, which contains almost the same chemical compositions as cement. As a new method for activation of GGBFS, a simple sonochemical route was developed to synthesize nanoparticles of GGBFS. Chemical composition of the GGBFS sample was characterized using X-ray fluorescence (XRF). Crystallinity, morphology and reactivity of the GGBFS samples were compared before and after the sonochemical process, by using Powder X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Thermal Gravimetry and Differential Thermal Analysis (TG/DTA). Based on the DTG results, Nano GGBFS showed a superior reactivity compared with the bulk form. Therefore, sonochemistry is an appropriate method for the activation of cement additives.

Background: This study aimed to synthesize some 2′, 3′, 4′-trichlorophenyl chalcones [(E)-1-(2, 3, 4-trichlorophenyl)-3-(substituted phenyl)-2-propen-1-ones] using solvent-free sulfated Titania catalyzed aldol condensation between 2, 3, 4-trichloroacetophenone and substituted benzaldehydes under microwave irradiation. To characterize these chalcones using analytical, physical and spectroscopic data and also to study their the spectral correlation and antimicrobial activities. Methods: Solvent free microwave assisted aldol condensation method was used for synthesizing substituted styryl 2′, 3′, 4′-trichlorophenyl ketones. They were characterized by UV, IR, NMR and mass spectroscopic data. The UV, IR, NMR spectral data were correlated with substituent constants, F and R parameters, using Hammett equation, to study the effect of substituents. The Bauer-Kirby method was used for the evaluation of antimicrobial activities of the synthesized chalcones. Results: The yields of the synthesized chalcones were more than 90%. The spectral data of these ketones had been correlated, using single and multi-linear regression analysis. These gave a satisfactory degree of correlations with some parameters and a fair degree of correlations with some parameters. Few chalcones had excellent antimicrobial activities, whereas, others showed poor antimicrobial activities. Conclusion: Easy work-up and handling, non-hazardous and environmentally benign aldol condensation method had been adopted for synthesizing chalcones with better yields. Some of the Hammett spectral correlations were found satisfactory with the observed spectroscopic data. Halo, methoxy, methyl and nitro substituted compounds had shown excellent antimicrobial activities based on their zone of inhibitions.

This study examines the environmental factors affecting the density of the exploited giant land snail species, Archachatina marginata, Achatina fulica and Limicolaria flammea in the Dassa-Zoumè district of Benin. Thirty plots of 30 m × 30 m were laid out, within four vegetation types (fallows, forest, woodlands and wood savannah). Inside each plot the numbers of each giant land snail species were counted, and soil characteristics were measured. ANOVA and generalized linear models (GLMs) with Poisson distribution were used to examine the influence of soil factors on the giant land snails. A. fulica has the highest mean density (507 snails/ha) while A. marginata has the lowest density (110 snails/ha). ANOVA showed no significant difference in density between habitat types for any species. The most parsimonious GLM model showed that the abundance of A. fulica was positively associated to the fine sands, fine silts and pH, while the interactions were negatively associated with the abundance of the species. The abundance of L. flammea was negatively associated with the fine sands, fine silts and pH, while the interactions were positively associated with the abundance of the species. As for A. marginata, the abundance was negatively associated with the fine silts, pH and litter, while the interactions were positively associated with the abundance of the species. The abundance pattern of forest molluscs is likely to be affected by different processes. Exploitation of these giant snails will affect their density, and further research is needed to establish appropriate levels of harvesting and habitat management.

Effect of thermal conductivity on gravitational instability of quantum plasma in the presence of fine dust particles has been investigated. Following the linearized stability theory and normal mode analysis, the paper established a general dispersion relation of the problem. Modified condition of Jeans gravitational instability is obtained due to quantum effect. Numerical calculations were performed to find the effect of each parameter on the growth rate of instability. The effect of fine dust particles does not affect the instability condition of the system but stabilizes the system by decreasing the growth rate of unstable mode. Curves show the destabilizing effect of thermal conductivity and stabilizing effect of quantum correction on the growth rate of unstable mode. The stability of the system is discussed by Routh-Hurwitz criterion of stability.

This paper describes the optical limiting performance of 2D ZnO nanoflakes and plates synthesized through a simple wet chemical method. Scanning electron microscopic imaging of these nanostructures revealed the shape evolution from the nanoflakes to nanoplates as the growth duration increased from 11 h to 18 h. The nonlinear absorption is studied using open aperture Z scan technique. The process behind the nonlinear absorption is predicted as two photon absorption and one photon assisted energy transfer to the nearby trapping sites. We observe the appreciable optical limiting threshold of 46.86 MW/cm² for high pump power of 436 MW/cm² for nanoplates compared with nanoflakes (169.49 MW/cm²).

The Gulf sand gecko (Pseudoceramodactylus khobarensis Haas, 1957) is a nocturnal gecko endemic to the Arabian Gulf countries. In this study we report the presence of this species in Qatar for the first time. Our findings bridge one of the current geographic gaps in the known distribution range of this species. In Qatar, the species has been found on the mainland and on two islands occupying coastal salty habitats with shrubs. The islands are the smallest where this species is known to occur. We believe that this gecko species is more widely distributed in Qatar than we report here and that an extensive inventory is required to map the full range of the species in Qatar and also in other countries of the Arabian Gulf.

By integrating Radio Frequency Identification (RFID) technology with Wireless Sensor Networks (WSN), it is feasible to route RFID data from readers and RFID enhanced wireless sensor nodes (WSN) into base-stations through existing WSN clustering protocols. WSNs for reducing energy consumption and improving stability period can use clustering algorithms. Clustering sensor nodes are a useful topology control technique, but these algorithms are not always suitable for heterogeneous WSNs. Previous constructive algorithms, such as LEACH and SEP are not always stable in heterogeneous WSNs. They are designed without regard to appropriate parameters, such as remaining power and confidence value of the nodes for WSNs. In this paper we suggest and introduce a novel stable heterogeneous cluster-based protocol with cluster member bounds for heterogeneous RFID enhanced WSNs, which called SHCP. In SHCP, the probability of cluster-heads (CHs) election are weighted by the primary energy of a node relative to that of other nodes in the network and cluster formation, based on nodes current energy, numbers of current members which belong to a CH, distance between CHs and nodes and distance between CHs and base-station. Our conclusion shows the simulation results show SHCP achieves longer stability time until the first node dies (FND), half nodes die (HND) and improves energy utilization in WSNs.

A characteristic property of esters is that, they undergo both oxidation and hydrolysis under similar conditions. Furthermore, the product of each process is an aldehyde (the product of hydrolysis is alcohol, which in turn undergoes oxidation to give an aldehyde). It is, therefore, difficult to find out which process is operative. The kinetics of the reaction offers an opportunity to resolve this uncertainty. This method is illustrated in this article with two examples: oxidation of esters by Tl³⁺ and oxidation of esters by Co³⁺. The method described in this paper familiarizes students with the basic techniques involved in following the reaction, such as quenching the reaction, ensuring that the aliquots of reaction mixture are equal, taking the reaction mixture at all time intervals in an identical manner, taking infinite readings and the use of a thermostat. It also provides familiarity with the use of integrated rate equation, plotting graphs, the evaluation of slopes on graphs and the calculation of rate constants.

Minerals have a profound impact on reproduction. The relations between estradiol-17β (E2) and blood mineral levels have been studied mainly in human and rats, but not in quail. Therefore, the aim of this study was to test the effect of E2 on serum mineral concentrations in Japanese quail (Coturnix japonica). The study was conducted at the Seljuk University animal farm thirteen week old female Japanese quails (n = 33) were housed in cages (25 × 35 × 48 cm) under a 16 hours light: 8 hours dark cycle. During the course of the study, birds were fed ad libitum with a diet supplying 20% crude protein, 2901 kcal/kg metabolic energy, 2.5% calcium (Ca), 0.35% phosphorus (P), 1.02% lysine, 1.02% methionine and cysteine mixture. After a 7-day adaptation period, the birds were randomly assigned to 3 groups, one control (n = 10) and two others as test groups (n = 11 and n = 12). Birds in test groups were subcutaneously injected with 0.1 or 0.2 mg E2. Blood samples were collected from the jugular vein and serum mineral concentrations were measured by HNO3 digestion method. Injection of 0.2 mg E2 resulted with a significant reduction in serum potassium concentration as compared to control group. Injection of 0.2 mg E2 caused a significant reduction in serum iron concentration as compared to 0.1 mg E2 injected group. Injection of 0.1 mg E2 caused a significant increase in serum chromium concentration over the control. Serum boron concentration was significantly high after the injection of 0.1 or 0.2 mg E2 over the control group. Effect of E2 on serum mineral concentration depends on injection dose. An injection of 0.1 or 0.2 mg E2 significantly increased serum boron concentration, which is an indication for the effect of E2 on bone mineralization and feed conversion ratio. Thus, administration of boron or E2 may protect postmenopausal women against osteoporosis and estradiol can be employed for the treatment of osteoporosis. Injection of 0.1 mg E2 caused a significant increase in serum chromium concentration, which indicates the function of E2 on body growth and reproductive performance. Injection of 0.2 mg E2 caused significant reduction in serum potassium (K) concentration, while there was a slight increase in serum sodium (Na) concentration. This indicates the involvement of E2 in rennin-angiotensin-aldosterone system.

Copper(II) complexes with novel chelator-type nucleosides: histidine modified 2′-deoxyriboadenosine (N-[(9-β-D-2′-deoxyribofuranosylpurin-6-yl)-carbamoyl]histidine) and histamine modified 2′-deoxyriboadenosine (N-[(9-beta-D-2′-deoxyribofuranosylpurin-6-yl)-carbamoyl]histamine) were studied by potentiometric and spectroscopic (UV–VIS, CD, EPR) techniques. A histidine or histamine residue was inserted in the purine part of a nucleoside. The ligands can act as bidentate or tridentate, depending on the pH range. The Cu(II) ions bind specifically to the modified deoxynucleosides forming very stable chelates. In acidic pH, a very stable dimeric complex Cu2L2 predominates, with coordination spheres of both metal ions composed of oxygen atoms from carboxylic groups, one oxygen atom from ureido group and two nitrogen atoms derived from a purine base and histidine ring. Above pH 5, deprotonation of carbamoyl nitrogens leads to the formation of CuL2, Cu2L2H-1 and Cu2L2H-2 species. The CuL2H-1 and CuL2H-2 complexes, with three or four nitrogens in Cu(II) coordination sphere, have been detected in alkaline medium. The cleavage of double stranded pEGFP-C1 in 5 mM Tris–HCl/5 mM NaCl buffer (pH, 7.5) by ligands and Cu(II) complexes, in the absence of any reducing agent has been studied by gel electrophoresis. The ligands and their copper complexes have introduced single-strand nicks into pEGFP-C1 plasmid DNA at micromolar concentrations, converting the supercoiled into open circular forms. The chelates have been found to be more active as DNA cleavers than the free ligands.

The present work investigates forced convective heat transfer characteristics of alumina-water nanofluids in a turbulent flow regime. Nanofluids are dilute colloidal suspensions with nano-sized particles ( < 100 nm) dispersed in a basefluid. The thermal conductivity values are measured by a steady state method, using a guarded hot plate (GHP) apparatus customized for liquids. The forced convective heat transfer characteristics are evaluated with the help of a test loop maintained in a constant heat flux condition. Controlled experiments under a turbulent flow regime are carried out using four particle concentrations (0.5vol%, 1vol%, 2vol% and 4vol %). The experimental results show that, the thermal conductivity of nanofluids increases with an increase in particle concentration and closely follow effective medium theories. However, the enhancement of heat transfer coefficients in the turbulent regime is observed to be within the measurement uncertainty.

Rod-shaped antimony sulphoiodide (SbSI) crystals were grown by utilizing elemental components of the compound. The material was characterized by X-ray diffraction (XRD), Raman and surface morphology by SEM. Electrical conductivity was measured on the pallets of powdered SbSI by the four-probe technique in the temperature range of 4–300K, and by the two-probe technique in the temperature range of 300–550K. SbSI shows semiconducting behavior in the temperature range of 300–550K and metallic below 300K. Activation energy of an electrical conduction between 300–550K, is 1.87 eV.