Iranian Journal of science and Technology (A: Siences)
Volume:37 Issue: 2, Spring 2013

Korovkin type approximation theorems are useful tools to check whether a given sequence of positive linear operators on of all continuous functions on the real interval is an approximation process. That is, these theorems exhibit a variety of test functions which assure that the approximation property holds on the whole space if it holds for them. Such a property was discovered by Korovkin in 1953 for the functions and in the space as well as for the functions 1, cos and sin in the space of all continuous 2π-periodic functions on the real line. In this paper, we use the notion of statistical lacunary summability to improve the result of [Ann. Univ. Ferrara, 57(2) (2011) 373-381] by using the test functions in place of and We apply the classical Baskakov operator to construct an example in support of our main result.

The purpose of this paper is the study of sub-hyperspaces of a hypervector space investigating some of their properties. In this regard, the notion of a normal fuzzy sub-hyperspace of hypervector space is introduced. Using it, we construct new fuzzy sub-hyperspaces. We also show that, under certain conditions, a fuzzy sub-hyperspace of a hypervector space is two-valued and takes the values 0 and 1.

In this paper, tanh method is applied to obtain exact solutions for two systems of nonlinear wave equations, namely, two component evolutionary system of homogeneous KdV equations of order 3 (type I as well as type II). Moreover, traveling wave hypothesis is used to obtain sech solution of type II coupled KdV system, in a more general setting. The results show that this method presents exact solutions compared with other methods and it is a powerful tool for solving systems of nonlinear PDEs.

Generalizing the notions of -fuzzy left (right) ideal, -fuzzy quasi-ideal, and -fuzzy bi-ideal, the notions of -fuzzy left (right) ideal, -fuzzy quasi-ideal and -fuzzy bi-ideal of semigroups are defined. Regular, intra regular and semisimple semigroups are characterized by the properties of these fuzzy ideals.

Coupled N-structures are introduced, and its application is discussed in BCK/BCI- algebras. The notions of a coupled N-subalgerba, a coupled N-ideal and a coupled NC- ideal are introduced, and their relations are investigated. Characterizations of a coupled N-ideal and a coupled NC-ideal are discussed. Conditions for a coupled N-subalgerba to be a coupled N-ideal are considered.

This research involves land cover changes of Osmancik Basin. The basin, is located in the northern part of Turkey, between 40o 48’ - 41o 40’ north latitudes and 34o 41’ - 35o 04’ east longitudes. The aim of this study is to research the permanent effects of human activities on natural land cover change. For this purpose, satellite images which enclose 1987 - 2010 periods are used as data. Erdas Imagine 10.0 software was used to analyse these images by using data images (Landsat TM) processing techniques. Land cover change nomenclature is made due to Corine (Coordination of Information on the Environment) Class 2 (Urban fabric, Forest, Shrub and/or herbaceous vegetation association, Heterogeneous areas, Inlands wetlands) and Class 3 (Rice fields). All images were independently classified using the supervised classification method of maximum likelihood algorithm. As a result, a period of over 20 years deforestation was calculated 62 % from 66663, 1 to 25266, 2 hectares between 1987 and 2010. In the same period, urban fabric changing was observed 190 % from 1949, 8 to 5671, 8 hectares. On the contrary, Inland wetlands have increased from 429, 4 to 1641, 6 hectares because of the built up new big dam named Obruk.

The Kamila Amphibolite Unit (KAU) of southeast Kohistan, Pakistan, represents a thick sequence of meta-volcanics which is underlined by the mafic-ultramafic rocks of the Spat Complex along the MMT (Main Mantle Thrust). The meta-volcanics of KAU are intruded by diorites, granitoids and tronjhemites of the Thak intusive complex. KAU is subdivided into four distinct units; Babusar, Niat and Jal amphibolites from south to north with a thin slice of Sumal amphibolites within Niat-Jal amphibolites. Niat and Jal amphibolites generally show strong foliation and alternating bands of mafic and felsic compositions. Niat amphibolites are generally fine to medium grained and composed of amphibole (hornblende and actinolite) and substantial quartz with subordinate plagioclase, epidote and chlorite. Magnetite, sphene, muscovite, and apatite occur as accessory minerals. The Jal amphibolites are fine grained and melanocratic and generally comprised of hornblende and plagioclase with subordinate quartz and sericite. Epidote and sphene occur as accessory minerals. Twenty six samples from both groups have been analyzed for whole rock geochemistry. The studied amphibolites fall in tholeiite group and show enrichment in HFS elements and depletion in LIL elements. Spider diagrams and MgO versus Zr plot show heterogeneous compositional patterns, with three distinct patterns: primitive, less evolved and more evolved. Average concentration of TiO2 (1.99 wt% for Niat amphibolites and 1.56 wt% for Jal amphibolites) and K2O (0.14 wt% for Niat amphibolites and 0.20 wt% for Jal amphibolites) exhibit MORB like composition whereas average Y/Nb ratio (8.9 for Niat amphibolites and 8.4 for Jal amphibolites) are close to N-MORB. Zr/Y vs Zr plot characterized the studied rocks as MORB and they fall in the ocean floor basalt (OFB) field on the triangular Ti/100, Zr, Y*3 diagram.

Information on the relationship between culture temperature and changes in the cell''s area, volume and area to volume (S/V) ratio is lacking. Cancerous epithelial-like cell lines SW480, SW742 and T-47D were cultured at 32, 37 and 42°C for 48hr. Digital images of cells were analyzed using software Imaged. Observed surface area, volume changes, and surface area to volume (S/V) ratio were significantly different at 32, 37 and 42°C in the three cell-lines tested (P<0.05). S/V ratios for all three cell lines at 37°C were significantly greater than that of at 42°C (P=0.0001).

In this paper, the thermodynamic properties of spin polarized strange quark matter at finite temperature in the presence of a strong magnetic field using MIT bag model have been calculated. We have also computed the equation of state of spin polarized strange quark matter in the presence of strong magnetic field and finally, using this equation of state, the structure of spin polarized strange quark star at different temperatures and magnetic fields has been investigated.

In this study, eight bacterial isolates showing a suitable resistance to heavy metals were obtained from electroplating effluents. The isolates were grown on nutrient agar including 1 mM of each heavy metal of cobalt (Co), chromium (Cr), mercury (Hg), zinc (Zn) and copper (Cu). The minimum inhibitory concentrations (MICs) of the isolates were determined using different concentrations of heavy metals (1-5 mM) by broth dilution method. One of the isolates showed higher MICs of 5, 5, 4, 3 and 3 mM when grown on Co, Cr, Hg, Zn and Cu, respectively and selected for further study. The bacterial identity was determined by various biochemical and physiological experiments. The optimum temperature and pH for the growth of the strain were 30˚C and 7, respectively. The isolate was resistant to ampicillin, cephalotin, amikacin and gentamicin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Comamonas with 99% similarity to Comamonas testosteroni; it was then designated as Comamonas sp. HM_AF12. Atomic absorption spectrometer analysis showed that 80% of chromium was removed from 5 mg/L of chromium solution after 1 h. The results suggest that Comamonas sp. HM_AF12 obtained from effluent owing to its high resistance to toxic heavy metals has great potential to be employed for bioremediation of chromium contaminated effluents.

In the present investigation electrodeposited Ni-Fe-W-S nano crystalline thin films were prepared in tri sodium citrate bath at bath temperature of 40˚C. Annealing of the electro deposited thin film was performed at 200˚ C temperature for one hour. X-ray diffraction technique (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDAX), Vickers Hardness Test (VHN), and Vibrating Sample Magnetometer (VSM) were utilized to study the as-deposited and annealing effects on the structural and magnetic properties of the film. X-ray diffraction (XRD) result indicated that the as-deposited film had crystalline size of 31 nm. Annealing treatment of the coatings produced the enhanced crystalline size of 26.6 nm. Due to the improvement of soft magnetic properties in the 200˚C annealed film, the saturation magnetization is enhanced by 88 × 10-3 emu/ cm2 (coercivity decreased to 14.6 Oe) compared with the case of as-deposited film at bath temperature of 40˚C. The magnetic flux density (Bs) of the annealed film was enhanced by 0.6328 Tesla. Hardness of the annealed film increased from 143 VHN to 151 VHN. This shows that the soft magnetic properties of Ni-Fe-W-S thin films are greatly enhanced by annealing at 200˚C which can be used in MEMS applications.

The karst-bauxite deposits of the Dehdasht region in the southwest of Iran, are situated unconformably between Cenomanian and Santonian shallow marine limestones. The white, gray, black, pisolitic, red and yellow bauxites are the main horizons in these deposits from bottom to top. In this study, the combinations of oxygen, hydrogen, carbon and sulfur isotopes of the main bauxite units were utilized to trace bauxitization processes, climatic and environmental conditions. The δ18O and δD values of boehmite and kaolinite minerals, not only suggest a likely inheritance relation between them, but also suggests no remarkable climate changes during occurrence of bauxite horizons in Cretaceous. The δ18O values of about -7 ‰ and -8 ‰ inferred for the waters at the time of kaolinite crystallization and achieved kaolinization paleo-temperature more than 30˚C, represent low paleo-latitude location of the study area during the Cretaceous. The negative δ13C values from the carbonate matrix of bauxite-bearing minerals, as low as -25 ‰, indicate carbon derivation from the biodegradation of organic matter under aerobic and anaerobic conditions. The positive δ34S values of pyrites reveale sulfate-limiting conditionduring diagenesis that is consistent with biological fractionation of sulfur in a closed system by sulfate-reducing bacteria.