Iranian Journal of science and Technology (A: Siences)
Volume:36 Issue: 1, Winter 2012

The treatment equimolar quantities of carboxylic acids with acid chlorides in the presence of ZnO brings about highly efficient unsymmetrical anhydrides at room temperature in solvent-free condition. Reactivity trends favored formation of the product using both electron deficient and rich aryl acids and acid chlorides.

In this paper, an effective direct method to determine the numerical solution of linear and nonlinear Fredholm and Volterra integral and integro-differential equations is proposed. The method is based on expanding the required approximate solution as the elements of Chebyshev cardinal functions. The operational matrices for the integration and product of the Chebyshev cardinal functions are described in detail. These matrices play the important role of reducing an integral equation to a system of algebraic equations. Illustrative examples are shown, which confirms the validity and applicability of the presented technique.

Highly active Cu (II) complex with 1,4-dihydroxy anthraquinone as a cheap and accessable ligand could be used as a catalyst for the preparation of structurally different propargylamines from a one-pot, three-component reaction of terminal alkynes, aldehydes, and secondary amines with high yields under solvent-free conditions. The 1,4-dihydroxy anthraquinone is a very efficient Cu(II) scavenger that is able to catalyse the A3-coupling reaction without pre synthesis of the catalyst.

Fennel (Foeniculum vulgare Mill.) is widely cultivated for its edible, strongly-flavored leaves, fruits, seeds and medicinal uses. As the wild and cultivated plants are influenced by environmental stresses, the effects of salt (25, 50 and 75 mM NaCl), nitrogen and iron deficiency (0 N, 0.5 N of Hoagland’s solution, 0 Fe and 0.5 Fe of Hoagland’s solution), 2°C cold (2, 3 and 4 h) and drought (3, 5 and 7 days) stresses on growth, pigment content, and antioxidant activity of fennel at the seedling stage were evaluated. All four stresses resulted in a significant reduction of fresh and dry weights, and chlorophyll a and b and β-carotene content of seedlings. The antioxidant activity of seedling extracts also increased significantly (P ≤ 0.05) in all stresses except for 5 and 7 days of drought.

In this work we deal with the question: how can one improve the approximation level for some nonlinear integral equations? Good candidates for this aim are semi orthogonal B-spline scaling functions and their duals. Although there are different works in this area, only B-spline of degree at most 2 are used for this approximation. Here we compute B-spline scaling functions of degree 4 and their duals, then we will show that, by using them, one can have better approximation results for the solution of integral equations in comparison with less degrees or other kinds of scaling functions. Some numerical examples show their attractiveness and usefulness.

Biofacies and palaeoecology of the limestone of the Jahrum Formation in the Lar area in the southwest of Iran (Zagros Basin) is addressed in this paper. Our detailed analysis of biofacies and palaeoecology shows that the Jahrum Formation in the studied area were deposited in a carbonate open shelf dominated by heterozoan and, subordinately, photozoan skeletal assemblages. Based on analysis of larger benthic foraminiferal assemblages and biofacies features, two major depositional environments are identified. These include inner shelf and middle shelf environments. The inner shelf facies is characterized by wackestone-packstone, dominated by various taxa of imperforate foraminifera. The middle shelf is represented by wackestone-packstone with a diverse assemblage of larger foraminifera with perforate wall. The distribution of the larger benthic foraminifera indicates that shallow marine carbonate sediments of the Jahrum Formation at the studied areas have been deposited in the photic zone of tropical to subtropical oceans.

In the present article, we focus on the numerical approximation of stochastic partial differential equations of Itˆo type with space-time white noise process, in particular, parabolic equations. For each case of additive and multiplicative noise, the numerical solution of stochastic diffusion equations is approximated using two stochastic finite difference schemes and the stability and consistency conditions of the considered methods are analyzed. Numerical results are given to demonstrate the computational efficiency of the stochastic methods.

The changes of Chl a fluorescence induction curve in response to different salinity levels in Canola (Barassica napus, L.) plants were investigated. The canola seedlings were exposed to salt stress (100 mM and 200 mM NaCl) for 7 days and Chl a fluorescence induction kinetics was analysed. By using the OJIP-test, various parameters like VJ, area, N, φPo, φEo, ψo, RC/ABS and PIABS were calculated and compared at different salinity levels and compared with the control plants. The results showed that the parameters related to the donor site of electron in PSII [Fv/Fo, φPo and φPo /(1-φPo)] were constant and unaffected by salt stress. In contrast, the parameters dependent on the acceptor site of the electron such as VJ, area, N, φEo, ψo and ψo /(1- ψo) significantly decreased with an increase in salt concentration. Also, the multi parametric index PIABS (performance index) showed enough sensitivity to salt stress as a useful parameter to screen the activity of photosynthetic apparatus in canola plant. Based on our results, we suggest that in response to salt stress the electron acceptor site of PSII, especially at fractions of the transfer of electron from QA to QB and QA redox turnovers is more affected. In conclusion, this fraction of electron transport chain of PSII is possibly the first and major target of salt stress at photosynthetic apparatus in canola plant.