SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801 -hypergroups and -semihypergroups associated to binary relations6980213010.22099/ijsts.2011.2130END. HeidariDepartment of Mathematics,Yazd University, Yazd, IranB. DavvazDepartment of Mathematics,Yazd University, Yazd, IranJournal Article20101012The concept of -semihypergroups is a generalization of semigroups, a generalization of semihypergroups and a generalization of -semigroups. In this paper, we study the concept of semiprime ideals in a -semihypergroup and prove some results. Also, we introduce the notion of -hypergroups and closed -subhypergroups. Finally, we study the concept of -semihypergroups associated to binary relations and give necessary and sufficient conditions on a set of binary relations on a non-empty set S such that S becomes a -semihypergroup or a -hypergroupSpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801A new edge detection method based on the analytic signal of tilt angle (ASTA) for magnetic and gravity anomalies8188213110.22099/ijsts.2011.2131ENA. H. AnsariDepartment of Mining and Metallurgical Engineering, Yazd University, IranK. AlamdarDepartment of Mining and Metallurgical Engineering, Yazd University, IranJournal Article20100608In order to obtain maximum information from magnetic and gravity anomaly maps, application of an edge<br />detection method is necessary. In this regard two commonly used methods are derivative filters and local phase filters. In this paper, a MATLAB code is expanded to combine an analytic signal filter and a tilt angle filter as a new edge detection filter called ASTA filter. This method was demonstrated on synthetic magnetic data from 3 models and also on real magnetic and gravity data from southwest England. Findings show that the boundaries of a causative body are enhanced more accurately using this new filter, compared with other edge detection filters. The source code in MATLAB format is available from the authors on request.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801Regarding the Kähler-Einstein structure on Cartan spaces with Berwald connection8999213210.22099/ijsts.2011.2132ENE. PeyghanDepartment of Mathematics, Faculty of Science, Arak University, Arak 38156-8-8349, IranA. AhmadiDepartment of Mathematics, Faculty of Science, Arak University, Arak 38156-8-8349, IranA. TayebiDepartment of Mathematics and Computer Science, Qom University, Qom, IranJournal Article20101101A Cartan manifold is a smooth manifold M whose slit cotangent bundle 0<br />T *M is endowed with a regular<br />Hamiltonian K which is positively homogeneous of degree 2 in momenta. The Hamiltonian K defines a (pseudo)-Riemannian metric ij g in the vertical bundle over 0 T *M and using it, a Sasaki type metric on 0 T *M is constructed. A natural almost complex structure is also defined by K on 0 T *M in such a way that pairing it with the Sasaki type metric an almost Kähler structure is obtained. In this paper we deform ij g to a pseudo-Riemannian metric ij G and we define a corresponding almost complex Kähler structure. We determine the Levi-Civita connection of G and compute all the components of its curvature. Then we prove that if the structure ( , , ) 0 T *M G J is Kähler- Einstein, then the Cartan structure given by K reduces to a Riemannian<br />one.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801Environmental impacts of natural contaminants and mining activities on the surface and agricultural soils in the Aq-Darreh river watershed, Takab, West Azerbaijan Province, NW Iran101111213310.22099/ijsts.2011.2133ENY. RahimsouriDepartment of Geology, Faculty of Sciences, Urmia University, Urmia 57153 - 165, I. R. of IranA. YaghubpurDepartment of Geology, Faculty of Sciences, Tarbiat Moalem University, Tehran, I. R. of IranS. ModabberiFaculty of Geology, University College of Science, University of Tehran, Tehran, I. R. of IranS. AlipourDepartment of Geology, Faculty of Sciences, Urmia University, Urmia 57153 - 165, I. R. of IranJournal Article20100425The concentrations of potentially toxic elements (As, Sb, and Hg) and some trace elements in 36 topsoil samples and 18 agricultural soil samples were measured at the Aq-Darreh River watershed, NW Iran. Based on the results of the chemical analysis and comparing them with different standards, it seems that the soils of the Aq-Darreh River watershed are polluted with As and Sb. This pollution results from geochemical background (natural contamination) and mining activities. Geochemical background values in topsoil and agricultural soils were estimated for As (429.7 ppm and 98.8 ppm), Sb (79.02 ppm and 3.98 ppm), and Hg (356 ppb and 2596 ppb). This research also indicates that mining activities have played a significant role in soil pollution and increasing As, Sb and Hg concentration in topsoils and As and Sb in agricultural soils. Results of sequential leaches and XRD analyses of both soil types showed that most of the As concentration is bound to amorphous iron hydroxides in soils, while Sb and Hg are bound to resistant minerals such as stibnite and cinnabar. Clay and carbonate minerals have a lower adsorption of these pollutant elements in both topsoil and agricultural soils.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801The measurement of returns to scale under a simultaneous occurrence of multiple solutions in a reference set and a supporting hyperplane with weight restrictions113116213410.22099/ijsts.2011.2134ENM. Mardani ShahrbabakSchool of Sciences, Math group, Universisy of Sistan and Baluchestan, IranA. A. NouraSchool of Sciences, Math group, Universisy of Sistan and Baluchestan, IranJournal Article20090725Sueyoshi and Sekitani in 2007 presented a paper that explores the measurement of Returns to Scale under a possible occurrence of multiple solution in a reference set and a supporting hyperplane. The occurrence of<br />multiple solutions is classified into Type I and Type II. Type I is an occurrence of multiple solutions in a reference set. Type II is an occurrence of multiple solutions on a supporting hyperplane passing on the reference set. In this paper we want to apply their method for estimating RTS under weight restrictions. For this goal we use tone’s method for estimating RTS under weight restrictions.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801Bivariations and tensor products117124213510.22099/ijsts.2011.2135ENM. M. EbrahimiDepartment of Mathematics, Center of Excellence in Algebraic and Logical Structures
in Discrete Mathematics, Shahid Beheshti University, G. C., Tehran, IranM. MahmoudiDepartment of Mathematics, Center of Excellence in Algebraic and Logical Structures
in Discrete Mathematics, Shahid Beheshti University, G. C., Tehran, IranJournal Article20090202The ordinary tensor product of modules is defined using bilinear maps (bimorphisms), that are linear in each<br />component. keeping this in mind, Linton and Banaschewski with Nelson defined and studied the tensor product in an equational category and in a general (concrete) category K, respectively, using bimorphisms, that is, defined via the Hom-functor on K. Also, the so-called sesquilinear, or one and a half linear maps and the corresponding tensor products generalize these notions for modules and vector spaces. In this paper, taking a concrete category K and an arbitrary subfunctor H of the functor U¢ = Hom (Uop ´U) rather than just the Hom-functor, where U is the underlying set functor on K, we generalize sesquilinearity to bivariation and study the related notions such as functional internal lifts, universal bivariants, tensor products, and their interdependence.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801On Matsumoto metrics of special Ricci tensor125130213610.22099/ijsts.2011.2136ENB. RezaeiFaculty of Science, Department of Mathematics, Urmia University, Urmia, IranM. Rafie-RadFaculty of science, Department of Mathematics Mazandaran University,
P.O. Box 47416-1467, Babolsar, IranJournal Article20090427In this paper, the Matsumoto metric with special Ricci tensor has been investigated. It is proved that, if is of<br />positive (negative) sectional curvature and F is of -parallel Ricci curvature with constant killing 1-form ,<br />then (M,F) is a Riemannian Einstein space. In fact, we generalize the Riemannian result established by Akbar-<br />Zadeh.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801Resource allocation in multi-server dynamic PERT networks using multi-objective programming and Markov process131147213710.22099/ijsts.2011.2137ENS. YaghoubiDepartment of Industrial Engineering, Iran University of Science and Technology, Tehran, IranS. NooriDepartment of Industrial Engineering, Iran University of Science and Technology, Tehran, IranM. BagherpourDepartment of Industrial Engineering, Iran University of Science and Technology, Tehran, IranJournal Article20100425In this research, both resource allocation and reactive resource allocation problems in multi-server dynamic PERT networks are analytically modeled, where new projects are expected to arrive according to a Poisson process, and activity durations are also known as independent random variables with exponential distributions. Such system is represented as a queuing network, where multi servers at each service station are allocated, and also each activity of a project is operated at a devoted service station with only one server located at a node of the network based on First Come First Serve (FCFS) policy. In order to propose a novel approach for modeling of multi-server dynamic PERT network, initially the network of queues is transformed into a stochastic network. Then, a differential equations system is organized to solve and obtain approximate completion time distribution for any particular project by applying an appropriate finite-state continuous-time Markov model. Finally, a multi-objective model including four conflicted objectives is presented to optimally control the resources allocated to the service stations in a multi-server dynamic PERT network, and the goal attainment method is further employed to solve a discretetime approximation of the primary multi-objective problem.SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801The Nehari manifold for a Navier boundary value problem involving the p-biharmonic149155213810.22099/ijsts.2011.2138ENN. NyamoradiDepartment of Mathematics, Faculty of Sciences
Razi University, 67149 Kermanshah, IranJournal Article20110104In this paper, we study the Nehari manifold and its application on the following Navier boundary value<br />problem involving the p-biharmonic<br /><br /><br /><br /> <br /> <br />0, on<br />( ) 1 ( , ) , in , 2<br />*<br />2<br />u u<br />f x u u u<br />p<br />u u p q <br />where is a bounded domain in RN with smooth boundary . We prove that the problem has at<br />least two nontrivial nonnegtive solutions when the parameter belongs to a certain subset of R .<br /><br />SpringerIranian Journal of Science and Technology (Sciences)1028-627635220110801Freshwater green algae Chlorella sp. and Scenedesmus obliquus enriched with B group of vitamins can enhance fecundity of Daphnia magna157163213910.22099/ijsts.2011.2139ENN. MehdipourDepartment of Marine Biology, Faculty of Marine Science and Technology,
Science and Research Branch, Islamic Azad University, Tehran, IranM. FallahiInternal Waters Aquaculture Research Institute, Anzali Port, Guilan, IranG. Azari TakamiDepartment of Aquatic Health and Diseases, Faculty of Veterinary Medicine, Tehran University, Tehran, IranG. VossoughiDepartment of Marine Biology, Faculty of Marine Science and Technology,
Science and Research Branch, Islamic Azad University, Tehran, IranA. MashinchianDepartment of Marine Biology, Faculty of Marine Science and Technology,
Science and Research Branch, Islamic Azad University, Tehran, IranJournal Article20100425One of the most important aims of aquatic hatcheries is availability to mass produce of Daphnia magna as a live food with high nutritional value in the shortest time. In the present study, D. magna fed with two freshwater green algae species, Chlorella sp. and Scenedesmus obliquus, enriched with different dosages of a mixture B group vitamins (0, 0.5, 1 and 2 ml.l-1) were compared at two stages (at the beginning of the culture and at the end of logarithmic growth phase). The results showed that increases in the B group vitamin levels in both enriched algae performed, increasing the fecundity and population growth rate in D. magna at the two compared stages, but significantly only with the control group (P<0.05). The highest fecundity and population growth rate obtained in D. magna was when they were fed algae enriched with 2 ml.l -1, but not significantly with 0.5 and 1 ml.l<br />-1(P>0.05).