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Showing 12 results for Type of Study: Original Manuscript

Esmaeil Azizpour,
Volume 11, Issue 2 (2-2011)

By using the Berwald connection, we show that there is a linear connection &nabla such that these are projectively equivalent and belong to the same projective structure on TM. We find a condition for the geodesics of the berwald connection under which &nabla is complete.
Mohammad Jahanshahi, Mojtaba Sajjadmanesh,
Volume 12, Issue 1 (11-2012)

Boundary value problems (BVPs) are one of the most important fields in engineering and mathematical physics. In self-adjoint case of these problems, there are some facilities to solve them, such as
eigenvalues of adjoint equations are real numbers and associated eigenfunctions make an orthogonal
basis system.
In this paper a new method for investigation of self-adjoint B.V.Ps including ordinary differential
equations (O.D.Es) is introduced. Based on this method, at first, some necessary conditions
are obtained by making use of fundamental solutions of adjoint equations. Then an algebraic system is made by this necessary conditions and boundary conditions of given boundary value problem.
Finally, by making use of Lagrangian identity and boundary values of unknown function, sufficient conditions for having a self-adjoint problem are presented.
, Akbar Rishakani, Mohammad Reza Shams Abad, Einolla Pasha,
Volume 12, Issue 1 (11-2012)

Modular multiplication modulo a power of two is one of the operators that is used in cryptography

specially symmetric cryptography. In this paper we investigate the statistical and algebraic properties of

this operator from the cryptographic viewpoint. At first we compute the distribution of the output of

modular multiplication modulo a power of two and the distribution of its component Boolean functions.

Then after presenting a criterion for measuring the imbalance of maps, we obtain the imbalance of

this operator and its component Boolean functions. At last we investigate the algebraic degree of the

component Boolean functions of this operator and present a lower bound for the degree of these

M Hasanabadi, M Nadaripari, T Behroz,
Volume 12, Issue 2 (11-2012)

Production optimization is an important and challenging task in oil industry. In the present paper, we look For an acceptable setting of Intelligent Control Valves (ICVs) which leads to optimum production respect To reservoir conditions and operational restrictions. The Design of Experiment (DoE) as a structured, Organized method is used to determine the relationship between different settings affecting petroleum Production. In this context, the Taguchi method and Response Surface Method are employed and tested on a horizontal well with few ICVs, in order to maximize oil production while minimizing produced Water. The summary of approach and computational results is reported. 
Nader Nematollahi, Azadeh Kiapour,
Volume 13, Issue 3 (11-2013)

In the Bayesian framework, robust Bayesian methods concern on estimation of unknown parameters, or prediction of future observation, by specifying a class of priors instead of a single prior. Robust Bayesian methods have been used extensively in actuarial sciences for estimation of premium and prediction of future claim size. In this paper we consider robust Bayes estimation of premium and prediction of future claim size under two classes of prior distribution and under the scale invariant squared error loss function. Finally, by a simulation study and using prequential analysis, we compare the obtained robust Bayes estimators of future claim size.
Zahra Feiznejad, Saeed Mahdavifar,
Volume 14, Issue 1 (4-2014)

The spin-1/2 Ising chain in presence of a magnetic field and the Dzyaloshinskii-Moriya interaction is considered. First, using the rotation operator the model is transformed to the anisotropic spin-1/2 XXZ model in presence of a longitudinal magnetic field and then, using the fermionization technique and mean field approximation, the diagonalized Hamiltonian is obtained. The thermodynamic behavior of the specific heat is studied. It is found that the maximum value of the specific heat shows dual behavior. Specially, in the region of fields less than quantum critical field, it decreases by increasing field but behaves inversely in the region of the magnetic fields more than the quantum critical field. In addition, the magnetization process is studied and it is shown that the Dzyaloshinskii-Moriya interaction influences the magnetization process. 
S. Mohammad Motevalli, Somayeh Sheikhian Azizi,
Volume 14, Issue 1 (4-2014)

In this paper, we investigated Stark mixing transition rate of muonic deuterium, pionic deuterium, kaonic deuterium and anti protonic deuterium exotic atoms in various density of deuterium and in various initial states. To this end, the effects of Stark mixing were studied by Borie-Leon and SCM models. In order to obtain exact results the experimental data on shift and width of  and of exotic atoms were used. The obtained results show considerable transition rate of muonic deuterium in various densities and in various initial state than other exotic atoms. 
Mina Ghiasi, B Noohi, M Zahedi,
Volume 14, Issue 4 (6-2015)

The most prevalent and important mechanism of bacterial resistance to &beta-lactam antibiotics, is the production of &beta-lactamase enzymes which inactivate these drugs by the hydrolytic cleavage of the four-membered &beta-lactam ring during two steps which is including the nucleophilic attack of the bridging hydroxide ion on the substrate and eventual protonation of the leaving amine group. During this reaction, metal ions play an important role in the catalytic process. Despite the availability of &beta-lactamase crystallographic structures, their mechanism of action is still unclear and no clinically useful inhibitors of these enzymes have been reported. Density functional theory (DFT) using B3LYP and 6-31G, 6-31G* and 6-311G** basis sets have been employed to calculate the details of electronic structure and electronic energy of catalytic reaction of CcrA enzyme active center from metallo-&beta-lactamase enzymes (M&betaLs), penicillin from &beta-lactam antibiotics, and the formed complexes including ES, ETS1, EI1, EI2, ETS2 and EP respectively, has been used. Also all the thermodynamic functions including ∆Hº, ∆Sº and ∆Gº to form two transition states, ETS1 and ETS2, and for the total reaction are evaluated at 25 °C, 31 °C, 37 °C and 40 °C and 1 atmosphere pressure. In all calculations solvent effects have been considered by using PCM method for water, ethanol, protein environment, nitro methane and carbon tetrachloride. Finally this reaction proceeds during an exothermic and spontaneous process, and the first step, the nucleophilic attack of the bridging hydroxide ion on the substrate, is the rate-limiting step
A Gharzi,
Volume 15, Issue 1 (4-2015)

Formation of feather and hair follicles during embryonic stage is nearly similar but whether they possess a similar structure and organization in mature stage as well? The aim of the present research is to study similarities and differences of these two follicles in adult rats and pigeons. To fulfill this task, after removing follicles from the skin, the follicles processed for light and transmission electron microscopy. The results provided here demonstrated that these two follicle types are similar in having the dermal papilla, epidermal matrix and epidermal stem cells. Moreover, the production of hair and feather fibers in them is almost the same. One of differences seen between these follicle is that, unlike the hair follicle in the feather follicle a distinct compartment, called the pulp, is observed at the top of the dermal papilla. At the center of this pulp as well as the dermal papilla a blood vessel exists, a character which never seen in the hair follicle. Another difference observed is related to the thickness of the basement membrane exists at the interface between the papilla and epidermal matrix. This membrane in feather follicle is much thicker than its hair counterpart. In addition, at the basal region of the feather follicle there is a distinct population of stem-like cells which could not be distinguished in the hair follicle. Based on results provided here it seems that the feather in birds and the hair in mammals have been adapted for different biological tasks.
Hamidreza Nassery, Zahra Kayhomayon, Mohammad Nakhaei,
Volume 16, Issue 42 (5-2015)

The present study aimed at identifying the nitrate transport in the groundwater of Lenjanat plain, Isfahan. Nitrate concentrations were measured seasonally and groundwater flow was modeled for nitrate transport simulation using MODFLOW and MT3DMS codes. The nitrate concentrations were compared with the human and livestock drinking water and irrigation water standards. The results show that nitrate concentrations are higher than the guidelines limits in groundwaters. The flow modeling reveals that the groundwater flow system of the study aquifer has been influenced by the aquifer hydrogeological characteristics. The falling watertable and reduce aquifer storage are due to the anthropogenic stresses on flow system. The transport model calibration and sensitivity analysis shows that nitrate leaching from agricultural land, first–order irreversible rate reaction, effective porosity and precipitation are the major factors affecting the entry and retention of nitrate in Lenjanat groundwater. Denitrification rate in the aquifer has been decreased due to high concentration of dissolved oxygen in groundwater and low extent of organic carbon. Half-life of nitrate in Lenjanat aquifer is more than 2.5 years. Nitrate transport in the aquifer is mainly by convection. Considering the calculated mass with transport model, the nitrogen leaching to groundwater of study area is 108 kg N ha-1 yr-1.
Behrooz Khadem, Amir Daneshgar, Fahimeh Mohebbipoor,
Volume 17, Issue 40 (9-2015)

In this paper we introduce a word based stream cipher consisting of a chaotic part operating as a chaotic permutation and a linear part, both of which designed on a finite field. We will show that this system can operate in both synchronized and self-synchronized modes. In particular, we show that in the self-synchronized mode the stream cipher has a receiver operating as an unknown input observer.
In addition we evaluate the statistical uniformity of the output and we also show that the system in the self-synchronized mode is much faster and lighter for implementation compared to similar self-synchronized systems with equal key size.
Alireza Keshvari, Sm Hosseni,
Volume 17, Issue 40 (9-2015)

A new technique to find the optimization parameter in TSVD regularization method based on a curve which is drawn against the residual norm [5]. Since the TSVD regularization is a method with discrete regularization parameter then the above-mentioned curve is also discrete. In this paper we present a mathematical analysis of this curve, showing that the curve has L-shaped path very similar to that of the classical L-curve and its corner point can represent the optimization regularization parameter very well. In order to find the corner point of the L-curve (optimization parameter), two methods are applied: pruning and triangle. Numerical results show that in the considered test problems the new curve is better than the classical L-curve.

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