A survey of symbiotic organisms search algorithms and applications

Nature-inspired algorithms take inspiration from living things and imitate their behaviours to accomplish robust systems in engineering and computer science discipline. Symbiotic organisms search (SOS) algorithm is a recent metaheuristic algorithm inspired by symbiotic interaction between organisms in an ecosystem. Organisms develop symbiotic relationships such as mutualism, commensalism, and parasitism for their survival in ecosystem. SOS was introduced to solve continuous benchmark and engineering problems. The SOS has been shown to be robust and has faster convergence speed when compared with genetic algorithm, particle swarm optimization, differential evolution, and artificial bee colony which are the traditional metaheuristic algorithms. The interests of researchers in using SOS for handling optimization problems are increasing day by day, due to its successful application in solving optimization problems in science and engineering fields. Therefore, this paper presents a comprehensive survey of SOS advances and its applications, and this will be of benefit to the researchers engaged in the study of SOS algorithm.

     

Antiradical Activity Evaluation of Some Plants Used in the Romanian Cuisine

The antiradical properties of alcoholic extracts from 11 plants used in Romania cuisine were screened by means of an improved chemiluminescence method and the results were verified with the DPPH method. The decrease of the luminescence signal due to the reaction between luminol and hydrogen peroxide has been measured in alkaline medium, at 420 nm, after adding the tinctures of the analyzed plants. It was found that the most active antioxidant is milfoil followed closely by rosemary, sweet marjoram, and thyme. Since most of the studied extracts have good smell and taste, it might be possible to use them as natural food additives that act both as antioxidants and as spices.     

Effect of phenol functionalized carbon nanotube on mechanical,dynamic mechanical,and thermal properties of isotactic polypropylene nanocomposites

In this work, multiwall carbon nanotubes (MWCNT) were functionalized with phenol and characterized by using Fourier transform infrared spectroscopy (FTIR). Isotactic polypropylene (iPP)/MWCNT composites of both the unfunctionalized and functionalized MWCNT were prepared by melt blending in a miniextruder at different loadings of nanotubes (i.e., 0.1, 0.25, 1.0, and 5.0 wt%). The tensile properties of the composites were found to increase with increase in nanotube loading with a maximum in Young's modulus being achieved at 1.0 wt% loading of phenol functionalized MWCNT. The differential scanning calorimetry (DSC) studies reveal the nucleating effect of MWCNT on the crystallization of iPP. Percentage crystallinity was found to increase on phenol functionalization of MWCNT. Results of X‐ray diffraction studies of the composites are in conformity with that of DSC studies. Dynamic mechanical studies reveal that the functionalized MWCNT causes many fold increase in the storage modulus, and the effect is pronounced in the case of functionalized MWCNT. POLYM. ENG. SCI. 2012. © 2011 Society of Plastics Engineers     

Prenatal tobacco use and risk of stillbirth: a case-control and bidirectional case-crossover study.

We sought to estimate the association between prenatal smoking and stillbirth in a longitudinal cohort using two study designs: a case-control study and a bidirectional case-crossover study. The analysis was conducted using the Missouri maternally linked cohort dataset from 1978 through 1997. In the case-control study, each mother contributed only one birth to the analysis. For the bidirectional crossover design, analysis was restricted to women who gave birth to at least one stillbirth, and the controls comprised all live births before and after the stillbirth. The independent association between prenatal smoking and stillbirth was computed using nonconditional (case-control design) and conditional (bidirectional case-crossover design) logistic regression. Prenatal smoking decreased from 29.7% in 1978 to 21.2% by 1997 (p<.001). The absolute risk of stillbirth was greater among smokers (7.7/1000) than nonsmokers (5.3/1000), p<.001. In the case-control design, the risk of stillbirth was 34% greater among smokers than nonsmokers (OR = 1.34, 95% CI 1.26-1.43). For each 10-unit increase in the number of cigarettes consumed per day prenatally, the likelihood of stillbirth rose by about 14% (p<.001). In the bidirectional case-crossover design, the association between stillbirth and smoking during pregnancy was confirmed, although the magnitude of the relationship was smaller (OR = 1.20, 95% CI 1.03-1.39). In conclusion, we found prenatal smoking to be a risk factor for stillbirth even after minimizing the influence of known and unknown sources of confounding as well as changes in temporal trend in prenatal smoking.     

Rheological behavior of polypropylene nanocomposites at low concentration of surface modified carbon nanotubes

This article reports the rheological behavior of nanocomposites of isotactic polypropylene with both unmodified multiwall carbon nanotubes (CNTs) and phenol and 1‐octadecanol (C18) functionalized CNT (f‐CNT) at 0.1, 0.25, 1.0, and 5.0 wt% of the nanofillers. The incorporation of CNT at low loadings of 0.1 and 0.25 wt% decreases the storage and loss modulus and complex viscosity of the system, especially for the case of using f‐CNT. Out of the two types of functionalizations, C18 functionalization registers the lowest modulus and viscosity and displays processing aid behavior at 0.1 wt% loading, which is believed to be due to the disruption of the polymer entanglements. As the nanofiller loading increases to 1 wt%, the disruption of polymer entanglements effect is balanced by the hydrodynamic effect and subsequently neat polypropylene (PP), and the filled PP systems show similar modulus and complex viscosity. As the nanofiller loading increases further to 5 wt%, the hydrodynamic effect becomes the dominating factor, and the modulus and the complex viscosity of the nanofilled system become greater than that of neat PP. Results suggest that the 0.1 wt% loading of C18 f‐CNT could be a useful processing aid additive for improving polypropylene processability. POLYM. ENG. SCI., 52:1868–1873, 2012. © 2012 Society of Plastics Engineers     

Energy-efficient Nature-Inspired techniques in Cloud computing datacenters

Telecommunication Systems - Cloud computing is a systematic delivery of computing resources as services to the consumers via the Internet. Infrastructure as a Service (IaaS) is the capability...