let r be an associative ring with identity, c(r) be the category of com-plexes of r-modules and flat(c(r)) be the class of all at complexes of r-modules. we show that the at cotorsion theory (flat(c(r)); flat(c(r))−)have enough injectives in c(r). as an application, we prove that for each atcomplex f and each complex y of r-modules, exti (f,x)= 0, whenever ris n-perfect and i > n.

Let R be an associative ring with identity, C(R) be the category of com-plexes of R-modules and Flat(C(R)) be the class of all at complexes of R-modules. We show that the at cotorsion theory (Flat(C(R)); Flat(C(R))−)have enough injectives in C(R). As an application, we prove that for each atcomplex F and each complex Y of R-modules, Exti (F,X)= 0, whenever Ris n-perfect and i > n.

In this article we explicitly construct Stäckel separable systems in separation coordinates with the help of separation curve as introduced by Sklyanin. Further, we construct explicit transformation bewteen separable and ‡at coordinates for ‡at Stäckel systems. We also exploit the geometric structre of these systems in the obtained ‡at coordinates. These coordinates generalize the well known ge...

In the present study, flow over flat and pooled stepped spillways was simulated three dimensionally. The VOF method and k- ε (RNG) turbulent model was used to simulate the flow over the stepped spillway. The results indicated that the numerical model was acceptably capable of simulating the flow over the pooled and flat stepped spillways for different discharges. Following that, the effect of d...

Purpose: Flat feet associates with altered knee kinematics, kinetics, as well as knee pain. Fatigue of plantar intrinsic foot muscles may increase the navicular drop. However, it is unclear how fatigue influences the knee pain in individuals with flat feet. The purpose of this study was to assess the effect of fatigue on knee kinematics and kinetics in flat feet people during walking. Methods:...

carbon molecular sieve membranes (cmsms) have been considered as very promising candidates for gas separation, in terms of separation properties as well as thermal and chemical stability. due to the numerous advantages and wide applications of carbon membranes, their application for gas separation is of special importance. because of the importance of carbon membranes and a large number of stud...

comin the present study, co2 removal from natural gas stream has been studied using a flat sheet membrane contactor. a three dimensional mathematical model is developed to describe the process. the model considers the transport of a gas mixture containing carbon dioxide and methane through a flat sheet membrane contactor module. the model is based on the non-wetted mode of operation, in which t...

there are many reports on the application of different hydrocolloids in the production of leavened breads; most of which show positive effects on bread quality. however, there is little information to prove such effect on flat breads. the main aim of this study was to improve the quality of barbari dough and bread (iranian flat bread) in terms of texture, taste and general acceptability of fres...

the main objective of this paper is to find the necessary and sufficient condition of a given finslermetric to be einstein in order to classify the einstein finsler metrics on a compact manifold. the consideredeinstein finsler metric in the study describes all different kinds of einstein metrics which are pointwiseprojective to the given one. this study has resulted in the following theorem tha...