In this paper, we present two regression functions to estimate gold coin futures price based on gold coin price, foreign exchange rate, price of gold traded globally and trend of time. The proposed model of this paper is used for price estimation of gold coin futures in Iran mercantile exchange (IME).
The proposed model of this paper is applied for historical data of future gold prices and the results are discussed. The preliminary results indicate that an increase on gold coin price could increase gold coin futures price. An increase on foreign exchange price has negative impact on gold coin futures and time horizon has positive impact on gold coin futures on IME.

The amount of damage induced by brittle fracture of cracked bodies depends considerably on the path of fractures. Therefore, prediction of the trajectory of fracture using suitable theoretical fracture criteria is very important for cracked structures. In this paper, using higher-order terms of Williams’s series expansion and the maximum tangential stress criterion, the mixed mode I/II crack growth path of an angled crack plate subjected to biaxial far field loading is investigated theoretically. To evaluate the accuracy of the theoretical results, they are compared with the experimentally reported trajectories for the angled crack plate specimen. It is shown that by taking into account the higher order terms of the Williams series expansion a very good agreement is observed between the experimental and theoretical mixed mode fracture paths in the angled crack problem. It was also observed that the theoretically determined initial angle of crack growth is consistent with the experimental results.

Generation of residual stress and structure deformation are the most important problems in the process of structure welding. Residual stresses inside and around the welded joints are harmful for integrity and proper functioning of the welded part. Tensile residual stresses near the weld zone may cause in developing brittle fracture, reduction of fatigue life or crack propagation caused by corrosion stresses. Welding residual stresses may even reach the yield stress of the part and can affect the thermal or mechanical working properties of it. Different thermal and mechanical approaches have been developed in the past in order to reduce these residual effects. Thus, both radiative and convective heat transfer methods have important roles in distribution of residual stresses during the welding process. In this study, convection and radiation effects on distribution of residual stress inside a welded part have been investigated for three different cases. In the first case, convection heat transfer was ignored and only effect of radiation on residual stress distribution was considered. In the second case, just the convection heat transfer applied on the model during the welding process. In another case, effects of radiation and convection heat transfer methods were investigated, simultaneously. Results of the current study showed that both radiative and convective heat transfer mechanisms have a significant share on distribution of residual stresses inside the welded part. It was also shown that the share of convection is greater than that of radiation heat transfer method.

Numerous failure curves are presented in this manuscript to predict the onset of sudden fracture in V-notched brittle materials under combined tension-shear loading conditions. The curves were developed in a computational manner in terms of the notch stress intensity factors and based on the suitable failure concept of the maximum tangential stress (MTS) utilized frequently in the past by the author and his co-researchers for predicting mixed mode brittle fracture in extensive notched specimens. Three extensively used notch angles and various notch tip radii were considered in the computations. A wide range of brittle materials were also taken into account by defining and using the material critical distance. Through predicting load-bearing capacity and notch bifurcation angle utilizing only the two basic material properties namely the ultimate tensile strength and the plane-strain fracture toughness, engineers can design more rapidly and conveniently the V-notched brittle components with the aim to withstand reliably against sudden fracture.

Tetraphenylporphyrin (TPP) and copper tetraphenylporphyrin (CuTPP) were synthesized and characterized by IR, UV-Vis, 1HNMR and 13CNMR. The CuTPP nanoparticles were synthesized by sonication and mixed solvent methods. These nanoparticles were characterized by AFM and SEM images and UV-Vis spectra. The catalytic activity of nanoparticles was investigated by oxidation of o-choloro and o-hydroxy benzyl alcohols in presence of molecular oxygen and isobutyraldehyde. The yields of oxidation of o-hydroxy benzyl alcohol by the two catalysts, CuTPP NPs and CuTPP, are 96.5% and ~ 2%, respectively. It is very obvious that the oxidation at the presence of CuTPP NPs catalyst is very high but selectivity for both reactants is 100%.?

A rapid one-pot method has been developed for the synthesis of azo dyes via ?sequential diazotization–diazo coupling of aromatic amines with coupling agents at room ?temperature in the presence of BF3.SiO2 as acidic catalyst. The obtained aryl diazonium salts bearing silica supported boron tri-flouride counter ion? was sufficiently stable to be kept at room ?temperature in the dry state.?

A regioselective synthesis of ethyl 6-aryl-3-propylpyridazine-4-carboxylates by one-pot three-component reaction of ethyl butyrylacetate with various arylglyoxals in the presence of hydrazine hydrate at room temperature in water was described.

A series of new 2-arylquinoxaline derivatives have been synthesized in high yield by condensation of aryl-1,2-diamines with arylglyoxals in DMF at 50-120 oC.

Hub covering problem is one of the most popular areas of research due to wide ranges of applications in different service or manufacturing industries. This paper considers a multi-objective hub covering location problem under congestion. The proposed study of this paper considers two objectives where the first one minimizes total transportation cost and the second one minimizes total waiting time for all hobs. The resulted multi-objective decision making problem is formulated as mixed integer programming. Simulated annealing is used to solve the resulted model and the performance of the proposed model is compared against two other alternative methods, particle sward optimization and NSGA-II. The results are compared in terms of four criteria including quality metric, mean ideal distance, diversification metric and spacing metric. The results indicate that the proposed model could perform better than the other two alternative methods in terms of quality metric but the results are somehow mix in terms of other three criteria.

Fuzzy logic has created suitable mathematics for making decisions in uncertain environments including professional judgments. One of the situations is to assess auditee risks. During recent years, risk based audit (RBA) has been regarded as one of the main tools to fight against fraud. The main issue in RBA is to determine the overall audit risk an auditor accepts, which impact the efficiency of an audit. The primary objective of this research is to redesign the audit risk model (ARM) proposed by auditing standards. The proposed model of this paper uses fuzzy inference systems (FIS) based on the judgments of audit experts. The implementation of proposed fuzzy technique uses triangular fuzzy numbers to express the inputs and Mamdani method along with center of gravity are incorporated for defuzzification. The proposed model uses three FISs for audit, inherent and control risks, and there are five levels of linguistic variables for outputs. FISs include 25, 25 and 81 rules of if-then respectively and officials of Iranian audit experts confirm all the rules.