Sharif Digital Repository

In this paper, we derive a theoretical model for the higher order FWM power in WDM networks with NZDSF fibers for the first time. We have investigated the higher order FWM power theoretically and by numerical simulations. Dividing the fiber into finite number of elements and applying the boundary conditions, allow us derive an expression for second order power penalty. At the end of each element we derive the first order FWM power for all wavelengths and use these values to calculate the second order FWM power in the next element. Consequently, for each channel we can compute the total second order FWM power penalty at the end of the fiber  

An ultra-efficient switching method for successive approximation register ADCs is proposed. In this method, the input signals are sampled in a special fashion to reduce the switching energy. Owing to the sampling method, only one reference voltage (Vq=Vref/4) is required to implement the switching steps. Therefore, in addition to reduction in the switching energy (due to the lower supply voltage), the precision of the DAC is improved. The proposed method reduces the switching energy and area by 99.41 and 50%, respectively, compared with the conventional method. © 2016 The Institution of Engineering and Technology  

A highly energy-efficient switching method for capacitor-splitting digital-to-analogue converter (DAC) in successive approximation register (SAR) analogue-to-digital converters (ADCs) is presented. In the proposed DAC, a bottom-plate sampling method is introduced which requires only one reference voltage (Vcm = 1/2Vref) during the entire DAC switching steps. Therefore, in addition to the switching energy reduction, the precision of the DAC is increased since only one reference voltage is used. The DAC average switching energy and the area are reduced by 98.44% and 50% compared with the conventional binary weighted DAC  

A sampling and switching method for a binary weighted digital-to-analogue converter (DAC) in successive approximation register (SAR) analogue-to-digital converters (ADCs) is presented. This sampling method is proposed to reduce the switching energy. Thanks to the proposed switching method, only one reference voltage (Vcm = 1/2 Vref) is required which helps to improve the precision of the DAC along with energy reduction compared with those methods that use more than one reference voltage. The switching energy and area of the DAC reduce by 97.66% and 50% compared with the conventional binary weighted DAC  

A highly energy-efficiency switching procedure for the capacitor-splitting digital-To-Analog converter (DAC) is presented for successive approximation register (SAR) analogue-To-digital converters (ADCs). In this procedure, the MSB capacitor is divided into its binary constituents. All output digital bits, except the least significant bit (LSB), is determined using reference voltage (Vref), while the common-mode voltage (Vcm) is used to determine the LSB. Therefore, the precision of the proposed SAR ADC is independent of the precision of Vcm except in the LSB. This method reduces the area by 75% compared to the conventional binary weighted DAC and reduces the switching energy by 96.89%. ©... 

Hot compression tests were carried out on a Fe-29Ni-17Co alloy in the temperature range of 900 °C to 1200 °C and at strain rates of 0.001-1 s-1. Dynamic recrystallization was found responsible for flow softening during hot compression. The flow behavior was successfully analyzed by the hyperbolic sine equation and the corresponding material constants A, n and α were determined. The value of apparent activation energy was determined as 423 kJ/mol. The peak and steady state strains showed simple power-law dependence on the Zener-Hollomon parameter. The dynamic recrystallization kinetics was analyzed using Avrami equation and the corresponding exponent was determined to be about 2.7. This... 

The hot ductility of Fe-29Ni-17Co alloy was studied in both cast and wrought conditions by hot tensile tests over temperature range of 900-1250°C and at strain rates of 0.001-1s-1. Over the studied temperature range, the wrought alloy represented higher elongation and reduction in area as compared to the cast alloy. Dynamic recrystallization was found responsible for the higher hot ductility of the wrought alloy and the improvement of hot ductility of the cast alloy at high temperatures. At temperature range of 1000-1150°C the wrought alloy exhibited a hot ductility drop while a similar trough was not observed in case of the cast alloy. It was also found that at temperatures of 1150-1250°C... 

In this publication, we reported an efficient MOF-based catalytic system for the synthesis of thiopyran and oxospiro-indolinethiopyran derivatives. For the first time, magnetic NH2.MIL-101(Fe)/ED was synthesized through anchoring FeCl3 on CoFe2O4 magnetic nanoparticles surface and then 2-aminoterphthalic acid was used to form MOF structure. In the final step, metal centers were modified with ethylenediamine (ED). Different techniques such as Fourier transmission infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, Transmission electron microscopy, Brunauer–Emmett–Teller analysis, and Thermogravimetric analysis were used to characterize the catalyst... 

Sensor network deployment is very challenging due to hostile and unpredictable nature of usage environments. In this letter, we propose two methods for the self-deployment of mobile sensors. The first one is a randomized solution that provides both simplicity and applicability to different environments. Inspired by simulated annealing, it improves both speed and energy conservation of the deployment process. The other method is suggested for environments where sensors form a connected graph, initially. At the cost of this extra limitation, we gain considerable improvements. © 2006 IEEE  

This paper presents the results of an experimental study on the flexural behavior of ten 10 × 15 × 120 (cm) steel reinforced high strength concrete beams under deflection control loading conditions. Test variable includes volumetric percentage of steel fibers (0%, 1.5%, 3%, 4%, 5%). The plain concrete strength was 30MPa. The monotonic concentrated load was applied at the center of the beam, the relative deflection was measured, and demec points were used to determine curvature of the beam. Load-deflection and moment-curvature diagrams have been obtained and plotted for each beam individually. Test results indicate that higher fiber content considerably improves flexural behavior and provides... 

This paper presents a new procedure for determining the fracture toughness of rock-like specimens using the diametric compression test with the center-cracked horseshoe disk (CCHD) method. Using finite element analysis, a dimensionless stress intensity factor was obtained and a formula was rendered for determining mode I fracture toughness. To evaluate the accuracy of the measurement results produced by the CCHD method, fracture toughness experiments were conducted on the same rock-like material using the notched Brazilian disk (NBD) method. The CCHD tests were simulated using a two-dimensional particle flow code for validation of the experimental results, and a great agreement between the... 

In the post-recession period, the business environment in developing countries is still relatively undesirable. Based on the reports published, the number of closed entrepreneurs are significantly more than the number of those newly established. These statistics also reflect that the development of entrepreneurship faces several challenges. However, a strategic management program must be accurately conducted to effectively control entrepreneurial challenges based on the limitation of time and financial resources. On the other hand, the program should provide an appropriate opportunity for competitiveness by producing better quality goods and services successfully marketed to consumers. The... 

Hepcidin is a peptide hormone that plays an important role in iron metabolism. We have produced a recombinant mouse hepcidin-1 by using baculovirus expression system. Its expression yield was 25 μg/ml when cell culture media were supplemented with a protease inhibitor cocktail. The recombinant mouse hepcidin-1 and synthetic human hepcidin-25 had similar effects on reducing ferroportin expression in J774A cell line and in peritoneal macrophages. However, synthetic human hepcidin-25 was more efficient than recombinant mouse hepcidin-1 in reducing iron concentration in blood circulation (p < 0.01)  

A three-phase dual active bridge (DAB) converter is designed and constructed as the DC/DC stage of a 50 kW fast charger station. Recently introduced 300A SiC power modules and drivers are utilized in the converter to obtain a high efficiency. Each module has two interconnected switches with anti-parallel diodes resembling a converter leg. It is observed that the driver halts the module operation as a result of protective actions such as over-current, gate under-voltage, or gate overvoltage. In such case the module operates as a leg with two diodes until an external hardware signal resets the driver. The aim of this paper is to provide analysis, simulation and experiments for a three-phase... 

This paper studies a two-echelon reverse supply chain (RSC) involving a remanufacturer and a collector, in which the collector receives the used products by paying a reward to consumers. The reward amount given to customers is crucial for encouraging them to exchange used products. An exchanged item is accepted if it meets the minimum acceptable quality level (AQL). Both the remanufacturing capacity and the quality of exchanged products present uncertainties. Under the buyback contract, the remanufacturer purchases used products at a higher price than in the decentralized and centralized cases from the collector. In return, the collector undertakes to repurchase a certain number of used... 

Within elasticity theory, the reduced form of a displacement field is obtained for general cross-ply composite laminates subjected to a bending moment. The firstorder shear deformation theory of plates and Reddy's layerwise theory are then utilized to determine the global deformation parameters and the local deformation parameters appearing in the displacement fields, respectively. For a special set of boundary conditions an elasticity solution is developed to verify the validity and accuracy of the layerwise theory. Finally, various numerical results are presented within the layerwise theory for edge-effect problems of several cross-ply laminates under the bending moment. The results... 

Blood and blood banks play an essential role in patient care. This study proposes a novel mathematical model for Blood Supply Chains (BSCs), which minimizes the total costs and maximizes donor satisfaction by reducing the system's waiting time. The model addresses several aspects of the BSC, such as locating collection centers, allocating blood donors to collection centers, inventory control in the main blood center, blood shortage and deterioration considerations, and queueing systems in collection centers over a planning horizon. Queueing systems lead to a better understanding of the BSC and provide an opportunity to investigate donors’ attendance and waiting times. A real-world case study...