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Search Results: 1 - 10 of 322305 matches for " H. P.; "
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Efficient FPGA implementation of AES 128 bit for IEEE 802.16e mobile WiMax standards  [PDF]
P. Rajasekar, Dr. H. Mangalam
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.74032
Abstract: In an advancement of communication field, wireless technology plays a predominant role in data transmission. In the timeline of wireless domain, Wi-Fi, Bluetooth, zigbee etc are some of the standards, which are being used in today’s wireless medium. In addition, the WiMax is introduced by IEEE in IEEE 802.16 for long distance communication, specifically 802.16e standard for mobile WiMax. It is an acronym of Worldwide Interoperability for Microwave Access. It is to be deliver wireless transmission with high quality of service in a secured environment. Since, security becomes dominant design aspect of every communication, a new technique has been proposed in wireless environment. Privacy across the network and access control management is the goal in the predominant aspects in the WiMax protocol. Especially, MAC sub layer should be evaluated in the security architecture. It has been proposed on cryptography algorithm AES that require high cost. Under this scenario, we present the optimized AES 128 bit counter mode security algorithm for MAC layer of 802.16e standards. To design a efficient MAC layer, we adopt the modification of security layers data handling process. As per the efficient design strategy, the power and speed are the dominant factors in mobile device. Since we concentrate mobile WiMax, efficient design is needed for MAC Security layer. Our proposed model incorporates the modification of AES algorithm. The design has been implemented in Xilinx virtex5 device and power has been analyzed using XPower analyzer. This proposed system consumes 41% less power compare to existing system.
Damping Factor Estimation of a Flexible-Matrix-Composite Body Pump  [PDF]
N. P. Kumar, H. Ghoneim
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.47009

Two very important factors which determine the effectiveness of a pump are its volumetric and power efficiencies. Yin and Ghoneim constructed a prototype of a Flexible-Matrix-Composite (FMC) body pump with a very high volumetric efficiency or pumping potential (the relative volume reduction due to a relative input stroke). The high volumetric efficiency is attributed to the geometry of the pump’s structure (hyperboloid) as well as the high negative effective Poisson’s ratio of the 3-layer [θ/β/θ] flexible-matrix-composite (carbon/polyurethane) laminate adopted for the body of the pump. However, the power efficiency of the pump was not evaluated. It is the objective of the current paper to obtain an estimate of the power efficiency of the pump. The viscoelastic properties of the 3-layer FMC (carbon/polyurethane) laminate are evaluated experimentally using the Dynamic Mechanical Analyzer (DMA) as well as analytically by applying the correspondence principle together with the micro-mechanics approach. In order to obtain an estimate of the power efficiency of the FMC body pump, the axial and shear loss factors of a laminated infinitely long cylindrical tube as functions of β and θ fiber orientation angles are determined employing the Adam and Bacon approach. The analysis engenders high loss factors (greater than 0.4), which suggests that the power efficiency of the proposed pump using the 3-layer carbon/polyurethane laminate may be low.

Synthesis and Characterization of a [Li0+xMg2-2xAl1+x(OH)6][Cl·mH2O] Solid Solution with X = 0 - 1 at Different Temperatures  [PDF]
A. Niksch, H. P?llmann
Natural Resources (NR) , 2017, DOI: 10.4236/nr.2017.86029
Abstract: The synthesis of a novel Li+ /Mg2+ /Al3+ containing layered double hydroxide (LDH) by using a hydrothermal synthesis route is represented in this work. The autoclaves were heated up to 100oC, 120oC, 140oC and 160oC for 10 h and 48 h with a water to solid ratio (W/S) of 15:1. The physicochemical properties of the synthesized LDHs were investigated by X-ray powder diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), thermo gravimetric and differential thermal analysis (TG-DTA), inductively coupled plasma optical emission spectroscopy (ICP-OES) and scanning electron microscopy (SEM). The formation of a solid solution phase depends strongly on the composition of the reactants and the synthesis temperature. Using an exact stoichiometric ratio of Li+/Mg2+/Al3+ resulted in the synthesis of amorphous phases without producing plenty of crystalline amounts of the expected solid solutions while using higher temperatures than 140oC resulted in a formation of AlO(OH). To avoid the formation of an Al containing amorphous phase or an AlO(OH) crystalline phase, the stoichiometric ratio of Li+ was changed. The results show solid solutions with the formula [Li0+xMg2-2xAl1+x(OH)6][Cl.mH2O] with X ≥ 0.9. The lattice parameters and chemical compositions for solid solutions with different compositions were determined and the pure solid solution with the highest amount of Mg (x = 0.9) is [Li0.9Mg0.2Al1.9(OH)6] [Cl.0.50H2O] with the lattice parameters a = 5.1004(4) Å, c = 15.3512(1) Å, V = 345.844(9) Å3. For X < 0.9 two separate phases, a Mg2+ and a Li+ dominated solid solution, are coexistent.
An IEEE 1547-Based Power Conditioner Test System for Distributed Energy Resources  [PDF]
Azen Y. Liu, P. H. Lan, H. H. Lin
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B181

Power conditioner, that is responsible for electric power conversion, is a critical component used in many renewable energy power generation systems. Most of the electric power produced by distributed energy resources cannot directly import to utility network without power conversion. Meanwhile, power conversion may includes several different types, for example AC/DC, and DC/AC, which is realized by a variety types of power conditioners in the electric power system. Currently, many concerns are focused on the operation of these power conditioners used in distributed energy resources due to the worse designing may cause the terrible influence on safety and performance characteristic of distributed energy resources. The power quality and reliability of interconnected electric power network may be affected as well. In the view of this, IEEE standards board provides a uniform standard for interconnection of distributed resources with electric power systems. It provides requirements relevant to the performance, operation, testing, safety considerations, and maintenance of the interconnection. Based on the IEEE 1547 standard, this paper presents a test system for power conditioners that are used in distributed energy resources or other renewable energy applications. Some of the test items that described in IEEE 1547.1 relevant to interconnection issues can be realized by proposed test system.

Nutritional, Physicochemical and Microbial Quality of Ultrasound-Treated Apple-Carrot Juice Blends  [PDF]
Jingfei Gao, H. P. Vasantha Rupasinghe
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.32031
Abstract: Three different apple-carrot juice blends (60:40, 75:25 and 90:10, v/v) were prepared and treated with ultrasound with comparison to the conventional thermal pasteurization. Total aerobic viable count (TAC) were significantly lower in juice blends with lower pH (apple-carrot ratio of 90:10, v/v) than the blends with higher pH after one month storage at 4?C. TAC were similar in ultrasound-treated and thermal pasteurized juice blends. Changes of turbidity of juice during storage followed the same pattern of TAC. Other juice quality parameters such as color, pH, titratable acid, total soluble solids, antioxidant capacity and beta-carotene did not change significantly during the storage period. The results suggest that ultrasound treatment has a potential to use as an alternative non-thermal technique for traditional thermal pasteurization process for maintaining the quality of beverages prepared from fruit and vegetable juices.
The Two-Constant Cost Model and the Estimation of the Cost Performance Evolutions of the Proton Exchange Membrane Fuel Cell Power Generation  [PDF]
H. F. Zhang, P. C. Pei
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.52A001

This paper aims at formulization and overview of the cost performance evolutions of proton exchange membrane (PEM) fuel cell power generation along with load and time. For this purpose, electricity-cost ratio (ECR) is proposed as the measuring parameter for the cost performance and a two-constant cost model is proposed to concisely describe the cost characteristic of the power generation as the opposite of a multi-constant cost model. Combination of the two-constant cost model and the ideal cell model developed recently produces an inclusive ECR equation that has three analytical expressions and thus allows of straight overviews of the cost performance evolutions in the working zones of the cells. The applications to real cells confirm the validity of the equation for operation optimization and technique evaluation of PEM fuel cells. And more insights into the cost performance evolutions are inferred by means of the equation to help promote the commercialization of PEM fuel cells.

Discrimination and Estimation of the Maximum Cost Performance of Proton Exchange Membrane Fuel Cell Power Generation with Seven Constants  [PDF]
H. F. Zhang, P. C. Pei
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.52A008

This paper is dedicated to analytical expression of the maximum electricity-cost ratio (M-ECR) point of the proton exchange membrane (PEM) fuel cell power generation as the function of cell constants and cost constants. That is to formulize the maximum cost performance (MCP) magnitude and the optimal final operating (OFO) location in the working zone based on the five-constant ideal cell model and the two-constant cost model. The issues are well resolved by introducing the concepts of economic voltage and cost factor and describing the movement of the M-ECR point with cost factor. According to mathematical derivations, the movement can be described in the form of MCP and OFO curves. The derivations lead to a complete set of discriminants and criteria of the M-ECR point of PEM fuel cells that theoretically cover all of cell specialties and all of cost specialties. The discriminants and criteria may act as a general tool for the operation optimization of a diversity of PEM fuel cells and the economic viability estimation of the power generation.

Asymptotic Harmonic Behavior in the Prime Number Distribution  [PDF]
Maurice H. P. M. van Putten
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.516244
Abstract: We consider \"\" on x > 0, where the sum is over all primes p. If Φ is bounded on x > 0, then the Riemann hypothesis is true or there are infinitely many zeros \"\". The first 21 zeros give rise to asymptotic harmonic behavior in Φ(x) defined by the prime numbers up to one trillion.
Peripheral Nerve Blockade in a Patient with Mastocytosis  [PDF]
Christopher H. Bailey, Kent P. Weinmeister
Open Journal of Anesthesiology (OJAnes) , 2015, DOI: 10.4236/ojanes.2015.53010
Abstract: Mastocytosis is a rare group of disorders with chronic and episodic mast cell release of mediators which can have systemic and cutaneous manifestations. Triggers of anaphylaxis include commonly used medications for anesthesia, analgesia, and muscle relaxation. There is little in the literature regarding local anesthesia in emergent surgery for patients with mastocytosis. This case details the use of a peripheral nerve blockade for multiple surgeries and pain control in a patient with biopsy-proven mastocytosis.
Mineralogical Transformations in Altasteel Electric Arc Furnace Dust Roasted with Na2CO3 and Secondary Ferrite-Forming Additives  [PDF]
P. C. Holloway, T. H. Etsell
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2008, DOI: 10.4236/jmmce.2008.71001
Abstract: The effect of secondary additives, such as CaCO3 and MnCO3, on the mineralogical transformations in Altasteel EAF dust (9.4% Zn, 31.9% Fe) during roasting with Na2CO3, and metal extractions during hot water and H2SO4 leaching of the roasted residues, was studied using a combination of techniques, including Design of Experiments testing, x-ray diffraction, scanning electron microscope/energy dispersive xray analysis and chemical analysis. The research objective was to promote the formation of acid insoluble metal ferrites during roasting to try to lower iron extractions during acid leaching. Neither additive was effective in reducing iron extractions due to the unexpected mineralogical changes caused during roasting by the addition of these secondary additives to this poorly crystalline EAF dust. Low CaCO3 or MnCO3 additions promoted the formation of manganese rich iron oxides (e.g., Mn2FeO4), instead of MnFe2O4, which caused more iron to be available to react with Na2CO3 during roasting to form acid soluble NaFeO2. Increased CaCO3 additions further increased iron extractions, by further increasing the formation of Mn2FeO4 ferrites, but increased MnCO3 additions at roasting temperatures above 950°C led to the formation of a ZnFe2O4-MnFe2O4 solid solution. While this resulted in lower iron extractions, lower overall zinc recoveries during acid leaching were also observed.
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