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Search Results: 1 - 10 of 155 matches for " Omari Zivzivadze "
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The Role and Importance of the Energy Saving in Georgia  [PDF]
Demuri Chomakhidze, Omari Zivzivadze, Petre Kachkachishvili, Akaki Kiladze
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.810113
Abstract: The role and importance of the energy saving in the conditions of Georgia are analyzed in this article. Based on the specific materials, the impact of the public labor fruitfulness and energy saving is compared to the volume of the whole inside product (WIP). It is said, that the reduction of the energy volume of WIP on 1% is giving approximately the same and in separate years even more effect in the augment of the volume of the WIP, compared to the rising the public labor productivity in the same way. In reference to this, the level of the main macroeconomic indicators of the development of the Georgian economy and the dynamics for 2013-2016 is studied in this article.
Numerical Investigation of a Mixed Convection Flow in a Lid-Driven Cavity  [PDF]
Reyad Omari
American Journal of Computational Mathematics (AJCM) , 2016, DOI: 10.4236/ajcm.2016.63026
Abstract: This study is devoted to the computational fluid dynamics (CFD) modeling of steady laminar mixed convection flow and heat transfer in lid driven cavity (10 ≤ Re ≤ 1000). The ratio of the height to the width of the cavity is ranged over H/L = 0.5 to 1.5. The governing equations are solved using commercial finite volume package FLUENT to visualize the nature of the flow and estimate the heat transfer inside the cavity for different aspect ratio. The simulation results are presented in terms of average Nusselt number of the hot wall, velocity profile, and temperature contours. It was found that the average Nusselt number inside the cavity is strongly governed by the aspect ratio as well as the Reynolds number. A parametric study is conducted to demonstrate the effect of aspect ratio on the flow and heat transfer characteristics. It is found that heat transfer enhancement was obtained by decreasing the aspect ratio and/or increasing the Reynolds number.
Thermal Properties of Ferrimagnetic Systems  [PDF]
Aiman Al-Omari
World Journal of Condensed Matter Physics (WJCMP) , 2011, DOI: 10.4236/wjcmp.2011.14018
Abstract: The heat capacity of some ferrimagnets has additional structures like a shoulder in the Schottky-like peak, or emergence of a second peak when an external magnetic field is applied. It is shown here that the ferromagnetic and anti-ferromagnetic elementary excitation spectra give rise to two independent heat capacity peaks, one enveloped by the other, which add up to give the peak for the total system. Taking this into account helps understand the additional structures in the peaks. Moreover, the classification of ferrimagnets into predominantly antiferromagnetic, ferromagnetic, or a mixture of the two is shown to be validated by studying them under additional influences like dimerization and frustration. Because these two are shown to influence the ferromagnetic and antiferromagnetic dispersion rela tions—and hence the quantities like heat capacity and magnetic susceptibility—by different amounts, the characterization of ferrimagnetic systems (1,1/2), (3/2,1) and (3/2,1/2) is brought out more clearly. Both these influences enhance antiferromagnetic character. PACS numbers: 75.10.Jm, 75.50.Ge.
Ferro- and Antiferromagnetic Aspects of Alternating Spin Systems  [PDF]
Aiman Al-Omari
World Journal of Condensed Matter Physics (WJCMP) , 2011, DOI: 10.4236/wjcmp.2011.14020
Abstract: Using linear spin-wave theory we have investigated the thermal properties of frustrated dimerized Heisenberg ferri- magnetic system with alternating spins and on one- and two-dimensional lattices. At intermediate temperature the susceptibility and the specific heat shows a minimum and a Schottky-like peak respectively. Frustration enhances the antiferromagnetic aspect in the system by causing a left-shift in the peak and the minimum which indicates that the antiferromagnetic behavior overbalance the ferromagnetic one at earlier temperatures. The effect of dimerization is different for the two form of the coupling constants. While the expanded form; , boosts the antiferro- magnetic behavior of the system by making a left-shift of the peak and the minimum, the distance-variable coupling constant; shifts them to the right opposing, for a while, the appearance of the antiferromagnetic aspect. The slope of after the minimum shows that the aspect of ferrimagnetic system with spins (3/2, 1) is more antiferromagnetic and the system with (3/2, 1/2) is ferromagnetic. Free energy and magnetization decreased by increasing dimerization as well as frustration. Both of them scales with PACS numbers: 75.10.Jm, 75.50.Ge.
Comparison of the Bayesian Methods on Interval-Censored Data for Weibull Distribution  [PDF]
Al Omari Mohammed Ahmed
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.48053
Abstract: This study considers the estimation of Maximum Likelihood Estimator and the Bayesian Estimator of the Weibull distribution with interval-censored data. The Bayesian estimation can’t be used to solve the parameters analytically and therefore Markov Chain Monte Carlo is used, where the full conditional distribution for the scale and shape parameters are obtained via Metropolis-Hastings algorithm. Also Lindley’s approximation is used. The two methods are compared to maximum likelihood counterparts and the comparisons are made with respect to the mean square error (MSE) to determine the best for estimating of the scale and shape parameters.
Influence of Control Modes of Grid-Connected Solar Photovoltaic Generation on Grid Power Flow  [PDF]
Zakaria Al-Omari
Engineering (ENG) , 2014, DOI: 10.4236/eng.2014.613083
Abstract: Integration of Solar Photovoltaic (PV) generation into an existing distribution system has many impacts on the system, with the power flow being one of the major issues. This impact is not generic for any network, but it may manifest itself either positively or negatively, depending on the grid configuration, interface control modes, operation mode, and load profile. Grid-connected PV systems have three control options of the local voltage controller of the interface DC-AC converter. These control modes are Power Factor control, voltage control, and Droop Voltage control. This paper aims at evaluating and comparing the impacts of those control modes on the grid power flow. A set of evaluation criteria and indices is defined and mathematically formulated. Based on the requirements of the used program (Power Factory Dig Silent V14.1.3), a computation plan (algorithm) has been proposed. The algorithm has been applied to a typical weak network and a wide range of simulations has been carried out. Simulation results have been thoroughly discussed and important findings have been concluded.
Loss of parental responsibility – a new legal instrument between need of protection of the best interest of the child and respect of parent fundamental rights
Sonila Omari
Academicus : International Scientific Journal , 2011, DOI: 10.7336/academicus.2011.04.08
Abstract: Foreign direct investments are very important for the implementation of strategic reforms, transfer of advanced technologies and managerial methods, thereby stimulating economic growth in developing countries and in particular, transition economies such as Albania is. During the last years, Albania experienced an increase in foreign investors’ interest in a wide range of sectors, with energy generation, telecommunication, cement production, mining, oil and industrial parks heading the list. However, the major obstacle factors for FDI inflows seem to remain the same: pervasive corruption, weak law enforcement, poor rule of law, lack of developed infrastructure, lack of a reliable energy supply and insufficiently defined property rights. Determining the factors that attract FDI, and furthermore identify the main characteristics of the host country’s economy, are essential to understand the reason of FDI inflows to a country or region. In the empirical perspective, various studies give different results. More specifically, this paper has focused on determining the factors for and against FDI in Albania.
Idempotent Elements of the Semigroups Bx(D) Defined by Semilattices of the Class ∑3(x,8) When Z7‡ Ø  [PDF]
Giuli Tavdgiridze, Yasha Diasamidze, Omari Givradze
Applied Mathematics (AM) , 2016, DOI: 10.4236/am.2016.73019
Abstract: In the paper, complete semigroup binary relation is defined by semilattices of the class \"\". We give a full description of idempotent elements of given semigroup. For the case where X is a finite set and \"\" , we derive formulas by calculating the numbers of idempotent elements of the respective semigroup.
An elliptic problem with arbitrarily small positive solutions
Pierpaolo Omari,Fabio Zanolin
Electronic Journal of Differential Equations , 2000,
Abstract: We show that for each $lambda > 0$, the problem $-Delta_p u = lambda f(u)$ in $Omega$, $u = 0$ on $partial Omega$ has a sequence of positive solutions $(u_n)_n$ with $max_{Omega} u_n$ decreasing to zero. We assume that $displaystyle{liminf_{so0^+}frac{F(s)}{s^p} = 0}$ and that $displaystyle{limsup_{so 0^+}frac{F(s)}{s^p} = +infty}$, where $F'=f$. We stress that no condition on the sign of $f$ is imposed.
Synthesis and properties of La1-x Cax Al O3
Diafi, M.,Omari, M.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2012, DOI: 10.3989/cyv.462012
Abstract: La1 –x Cax Al O3 (0 ≤ x ≤ 0.6) perovskite-type oxides were prepared by co-precipitation method using metal nitrate salts as cation precursors and NaOH solution as the precipitating agent. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) results indicate that decomposition of the precursor to the oxide begins at ~ 800°C. Powder X-ray diffraction (XRD) patterns confirm the formation of the perovskite phase. Both undoped and doped lanthanum aluminates show two IR active vibrational modes at 450 and 670 cm 1 which are assigned to AlO6 octahedra of the oxide matrix. The microstructure and morphology of the compounds show that the particles are nearly spherical in shape and are agglomerated. Electrochemical measurements indicate that the catalytic activity is strongly influenced by lanthanum doping. The highest electrode performance is achieved with large calcium content. Se prepararon diferentes óxidos tipo perovskita con formulación La1 –x Cax Al O3 (0 ≤ x ≤ 0.6) mediante método de coprecipitación empleando sales nitrato como precursores catiónicos y NaOH como agente precipitante. Los resultados de análisis térmico diferencial (DTA) y análisis termogravimétrico (TGA) indican que la descomposición del precursor del óxido comienza a ~ 800°C. Los patrones de difracción de rayos-X de polvo (XRD) confirman la formación de la fase perovskita. Los aluminatos de lantano, tanto dopado como no dopado, muestran dos modos vibracionales activos a 450 y 670 cm-1 que se asignan a octahedros AlO6 de la matriz del óxido. La microestructura y morfología de los compuestos muestran que las partículas son de forma próxima a la esférica y aparecen en forma de aglomerados. Las medidas electroquímicas indican que actividad catalítica se ven fuertemente influenciadas por el dopaje con lantano. La mayor actividad del electrodo se alcanza con altos contenidos de calcio.
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