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This note provides some extensions on optimal policies on price, warranty length and production rate proposed by Wu et al. (2009) . [1] (Wu, C.C.; Chou, C.Y.; Huang C. Optimal price, warranty length and production rate for free replacement policy in the static demand market. Omega 2009; 37: 29-39.) More specifically, the assumptions of the original paper is extended in this note from the production rate being positive and the second derivative of the demand function with respect to price and warranty-length being negative to no restrictions on both  

Ornamental stone sawability is important in predicting the prime cost of production and planning of the stone quarries and factories. Ornamental stone sawability with two standard methods, wire and circular sawing, is dependent on many parameters including; the stone that be sawn and machine characteristics and saw operating characteristic. The investigation of these parameters and the determination of the optimum working conditions for sawing machines in the stone industry is significant for establishing the most suitable and economic usage of the sawing method in the future. Up to now, various attempts have been made to determine these parameters. In this review paper, the important... 

The nature of molecular transmitter imposes some limitations on the molecule production process and its storage. As the molecules act the role of the information carriers, the limitations affect the transmission process and the system performance considerably. In this paper, we focus on the transmitter's limitations, in particular, the limited molecule production rate and the finite storage capacity. We consider a time-slotted communication where the transmitter opens its outlets and releases the stored molecules for a specific time duration to send bit '1' and remains silent to send bit '0'. By changing the Release Duration (RD), we propose an adaptive RD modulation. The objective is to... 

The prediction of rock sawability is very important in the cost estimation and the best planning of the plants. Rock sawability depends on the machine characteristics and rock mechanical properties. In this study, a new classification was developed with the respect to rock mechanical properties such as Uniaxial Compressive Strength, Brazilian tensile strength, Schmidt hammer value and Los Angeles abrasion loss. Using this system the carbonate rock sawability index (CRSi) of several types of carbonate rock was evaluated and classifi ed into fi ve categories and then a new model was developed with the respect to CRSi and machining characteristics by using the statistical analyses for... 

The differential multiplicity of dileptons in a hot and magnetized quark–gluon plasma, ΔB≡dNB/d4xd4q, is derived from first principles. The constant magnetic field B is assumed to be aligned in a fixed spatial direction. It is shown that the anisotropy induced by the B field is mainly reflected in the general structure of photon spectral density function. This is related to the imaginary part of the vacuum polarization tensor, Im[Πμν], which is derived in a first order perturbative approximation. As expected, the final analytical expression for ΔB includes a trace over the product of a photonic part, Im[Πμν], and a leptonic part, Lμν. It is shown that ΔB consists of two parts, ΔB ∥ and ΔB ⊥,... 

The prediction of production rate in ornamental stones sawing is very important in cost estimation and process planning of the rock sawing plants. The main aim of this paper is finding a mathematical correlation between production rate and rock brittleness indexes. The utilized data have been collected from several stone factories in Iran. Seventeen different granite and carbonate rocks have been experienced sawing conditions with large-diameter circular saws. The laboratory tests such as uniaxial compressive strength and tensile strength, were carried out on the rock samples which were collected from these factories. The ratio of compressive strength to tensile strength (B1), the ratio of... 

Whole level of the erosion and the resistance of rocks which were composed closured have been studied, besides, the impact of temperature and laser irradiation for more investigation about this issue has been involved before all. This subject more reveals the matter which laser absorption on the laboratory scale using laser to what extent can cause the augment of the relative permeability and secondary porosity of reservoir rock, that of the vertical and horizontal useful connectivity and eventually that of the positive transferability. This research has been carried out in the form of case study on one of Iranian south west formations in north east of Behbahan city in Iran, either the rate... 

The nature of molecular transmitter imposes some limitations on the molecule production process and its storage. As these molecules act the role of the information carriers, their limitation affect the transmission process and the system performance considerably. In this paper, we focus on these limitations at the transmitter, the limited production rate and finite storage capacity. We consider a time-slotted communication where the transmitter opens its outlet and releases the stored molecules for a time duration to send bit '1' and remains silent to send bit '0'. By changing the duration molecules are released, we propose an adaptive pulse-width modulation. The objective is to find the... 

This paper deals with the issue of economic batch quantity (EBQ) in a single machine system in which defective items are produced in each cycle of production. The accumulated defective items produced in a period, consisting of several equal cycles, are all reworked in the last cycle of this period called the rework cycle. At the end of each period the whole process will start all over again. We assume that there is a limitation on the total defective items. We also do not adopt the restriction that the rework process rate be equal to the normal production rate. In addition we assume that there is a set up time for rework process. Further we assume that the number of rework cycles be as small... 

In this paper we intend to obtain the economic batch quantity (EBQ) for an imperfect production system in which defective items are produced in each cycle of production. In the litrature of inventory control when the rework is done on defective items it is assumed that the production rate of the rework process is constant and the setup time for rework is ignored. Here we assume that due to the nature of the rework process its production rate is different from the normal production rate and is stochastic. We also assume that after each production run the rework process starts immediately after a non-zero setup time for the rework. Further we assume that the inspection costs during the normal... 

In this paper, we explore the Wigner entropy production rate in the stationary state of a two-mode Gaussian system. The interacting modes dissipate into different local thermal baths. Also, one of the bosonic modes evolves into the squeezed-thermal state because of the parametric amplification process. Using the Heisenberg-Langevin approach combined with the quantum phase-space formulation, we get an analytical expression for the steady-state Wigner entropy production rate. It contains two key terms. The first one is an Onsager-like expression that describes heat flow within the system. The second term results from vacuum fluctuations of the baths. Analyses show that self-correlation between... 

Naturally fractured reservoirs (NFRs) contribute in large extent to oil and gas production to the ever increasing market demand of fossil energy. It is believed that the vertical displacement of oil during gas injection assisted by gravity drainage (GAGD) is one of the most efficient methods for oil recovery in these reservoirs. Hence, in this work, unconsolidated packed models of cylindrical geometry surrounded by fracture were utilized in order to perform a series of flow visualization experiments during which the contribution of different parameters such as the extent of matrix permeability, physical properties of oil (viscosity, density, and surface tension) and the withdrawal rate was... 

The main purpose of this study is to compare the many different rock properties in the rock sawability. The comparison was realized with the combination of the analytic hierarchy process (AHP) and Fuzzy Delphi method and also TOPSIS method. The analysis is one of the multi-criteria techniques providing useful support in selecting among several alternatives with different objectives and criteria. FDAHP method was used in determining the weights of the criteria by decision makers and then ranking the sawability of the rocks was determined by TOPSIS method. The study was supported by the results obtained from a questionnaire carried out to know the opinions of the experts in this subject.... 

This experimental study is aimed at evaluation of the performance of secondary WAG injection in carbonate cores at different pressures. To do so, a comprehensive series of high-pressure high-temperature (HPHT) core flooding tests are conducted. The fluid system includes reservoir dead and live crude oil, CO 2, and synthetic brine while the chosen porous media consists of a number of fractured carbonate core samples. Parameters such as oil recovery factor, water and oil production rates, and pressure drop along the core are recorded for both dead and live oil. According to results, at first increasing pressure improves the oil recovery, but this improvement after MMP is not as significant as... 

In this study, the feasibility of producing power and hydrogen from the waste heat of different City Gate Stations (CGSs) is investigated to select the optimal working conditions. A thermodynamic model is developed for a proposed system combined of the CGS station, the Rankin cycle and the extended hydrogen production cycle. Initially, six CGS stations are simulated based on energy, exergy-economic and environmental analysis and then a comparative study is conducted between different stations. The results of numerical modeling show that the Mashhad-old station with 5315 kW and 31.062 ton/year has the highest amount of power and hydrogen production among other stations, respectively. It is...