Improved AODV route recovery in mobile ad-hoc networks using a genetic algorithm

An important issue in ad-hoc on-demand distance vector (AODV) routing protocols is route failure caused by node mobility in the MANETs. The AODV requires a new route discovery procedure whenever a route breaks and these frequent route discoveries increase transmission delays and routing overhead. The present study proposes a new method for AODVs using a genetic algorithm to improve the route recovery mechanism. When failure occurs in a route, the proposed method (GAAODV) makes decisions regarding the QOS parameter to select source or local repair. The task of the genetic algorithm is to find an appropriate combination of weights to optimize end-to-end delay. This paper evaluates the metrics of routing overhead, average end-to-end delay, and packet delivery ratio. Comparison of the new algorithm and AODV (RFC 3561) using a NS-2 simulator shows that GAAODV obtains better results for the QOS parameters

On the Pull-Out Behavior of Hooked-End Shape Memory Alloys Fibers Embedded in Ultra-High Performance Concrete

This study presents a three-dimensional non-linear finite element investigation on the pull-out behavior of straight and hooked-end Shape Memory Alloys (SMA) and steel fibers embedded in Ultra-High Performance Concrete (UHPC) using a single fiber pull-out model. A bilinear cohesive zone model is used to characterize the interfacial traction separation relationships. The Concrete Damage Plasticity (CDP) model is used to simulate UHPC, and the mechanical behavior is obtained through experimental tests. Parametric studies are conducted to evaluate the effects of fiber materials, fiber diameters, and hook angles on the load-displacement behavior. A good agreement between the numerical and experimental results is obtained. It is found that the hooked-end fibers with a smaller diameter and a hook angle of 40° can be a better choice for structural application. Furthermore, it is observed that the use of SMA fibers significantly improves the pull-out performance between fibers and UHPC

Decolorization of the dye reactive black 5 using Fenton oxidation

Study on the effect of Fenton process on decolorization and mineralization of RB-5 in aqueous solution is presented in this work. Batch experiments were carried out to find the optimal operational conditions including pH, temperature, H2O2 dosage, FeSO4 dosage and RB-5 concentration at low cost. Degradation of RB-5 dye as an organic pollutant was monitored based on decolorization and mineralization extents of the model solution determined by UV-vis spectrophotometric and chemical oxygen demand (COD) analysis respectively. Optimum pH and temperature for 250 mg/L RB-5 were observed at 3.0 and 40°C respectively and using 50 mg/L of FeSO4 and 300 mg/L of H2O2 resulted in generation of 58.9% COD and 97% color removal after 10 min reaction by Fenton. It is concluded that Fenton process can provide better result for decolorization compared to COD removal in the treatment of textile effluent.Keywords: Decolorization, black 5, Fenton oxidation, dyeAfrican Journal of Biotechnology Vol. 12(26), pp. 4115-412

Theoretical foundations of organizational problem solving methodologies in Operational Research

Paradigms are some principles and assumptions, which define frameworks and research priorities in each discipline. Many believe that operational research (OR) is not a science and like many other sciences does not have any paradigm. However, since OR is committed to scientific methods, therefore it contains a methodological paradigm. The purpose of this paper is to consider theoretical methodologies in the field of OR. This paper performs a review on the existing literature based on interpretive hermeneutic approach. Based on literature review, the study determines four principles and assumptions for each OR paradigms and a classification of the methods are presented. The results show that OR has four main paradigms and there are many methods in OR fields to tackle a particular problem where each problem belongs to a particular paradigm. In addition, instead of using a particular method in problem situations, we can implement a combination of methodologies

Communication strategies of English native speaker teacher in the teaching and learning process in a kindergarten

In Dyatmika Kindergarten, the students came from different cultural backgrounds and nations. They were taught by English native speaker teacher in English sessions. The students sometimes might understand the intention of the teacher; however, sometimes they might not understand at all. Therefore, the teacher should know how they communicate with the students to avoid misunderstanding. This study aimed at identifying, describing and explaining communication strategies used by English native speaker teacher at Dyatmika Kindergarten during English sessions of the teaching and learning process. This study used descriptive qualitative design, and the data collected through observation and interview. The data were analyzed using taxonomy of communication strategies by Dornyei and Scott (1995). The result indicated there were thirteen communication strategies used by the English native speaker teacher in teaching and learning process. The use of communication strategies by English native speaker teacher was expected to inspire other teachers inside and outside Dyatmika Kindergarten when they communicate with students and make the students understand the message conveyed by the teachers

Pheochromocytoma-induced reverse tako-tsubo with rapid recovery of left ventricular function

Pheochromocytoma is a rare, catecholamine-secreting tumor of neuroendocrine cells. It has been documented to present atypically as myocardial ischemia, arrhythmias, or congestive heart failure. We present the case of a patient who had transient cardiomyopathy with hypokinesia of the basal portions of the left ventricle and hyperkinesia of the apex triggered by a pheochromocytoma crisis similar to that of tako-tsubo cardiomyopathy, but with an inverse left ventricular contractile pattern (‘inverted tako-tsubo’). (Cardiol J 2012; 19, 5: 527-531

Assessment of the Optimum Depth of Sealing Cutoff Walls in the Clay Core of Peygham-Chay Dam

Seepage is one of the most substantial factors in the embankment dams design. The Cutoff wall method is the ideal construction solution for controlling flow through the foundation of earth dams. In this study, the cutoff wall method is investigated at the site of the Peygham-Chay dam (Study area). According to the dam site, in terms of its materials as well as their different permeability, water influx is a potential hazard at the site. For this purpose, SEEP/W program as the finite element approach was employed to estimate the seepage and design of the optimum depth of the sealing element. The results of numerical analyzes imply that the sealing component is not needed because of the low permeability in the primary 260 m at the left abutment of the dam. Also, the optimum depth of the cutoff wall is evaluated as 15 m at the rest of the dam axis

Simultaneous doxorubicin encapsulation and in-situ microfluidic micellization of bio-targeted polymeric nanohybrids using dichalcogenide monolayers : A molecular in-silico study

The rate of Riboflavin (RF) consumption in cancerous cells is interestingly high and this might imply the use of RF ligand in nanocarriers in order to target anticancer drugs into cancer cells. This study aimed to develop a hybrid drug carrier of Doxorubicin (DOX) loaded on RF targeted micelles composed of hydrophobic polylacticglycolic acid (PLGA) and hydrophilic polyethylene glycol (PEG). In this regard, a simultaneous encapsulation of DOX and in-situ micellization as well as the self-assembly of PLGA-PEG-RF molecules were investigated. Moreover, the effects of microfluidic environment and transition metal dichalcogenide (TMD) nanolayers on the micellization properties (e.g., stability, size, and self-assembly interaction energies) of nanocarriers were simulated for the first time. To this purpose, the simulations were performed using two non-microfluidic methods as well as a novel microfluidic one. The molecular simulations revealed that all of the selected TMDs, especially MoSe2, had a great impact on the stability and size of nanocarriers. MoSe2 significantly enhanced the loading capacity as well as the stability of RF-targeted micelles and reduced the size of nanocarriers. Likewise, the results of various analyses demonstrated that the microfluidic method is the most effective way to synthesize nano carriers with higher stability and smaller particle size. Hence, the use of MoSe2 monolayer, micelle containing RF, and microfluidic method were believed to be the best approach in order to improve the quality of micelles. The present work sheds new light on the use of TMDs in the synthesis of smart carriers for cancer treatment.Peer reviewe