Monitoring peroxide value in oxidized emulsions by Fourier transform infrared spectroscopy

Soybean oil (SBO) was blended with 10–40% palm kernel olein (PKO) to obtain SBO:PKO blends with different degrees of unsaturation. Oil‐in‐water (O/W) emulsions were then prepared with 70 wt‐% of SBO or SBO:PKO blends and monitored for their chemical destabilization after an accelerated oxidation process up to 12 days at 60 °C. The formation rate of hydroperoxides, as demonstrated by peroxide value (PV) evolution, throughout the oxidation period was relatively high for a fully SBO‐based emulsion as compared to those with PKO incorporation. Fourier transform infrared (FTIR) spectroscopic method was also performed in parallel with PV determination, providing further information on structural changes of the functional groups due to lipid oxidation in the emulsions. By using a partial least square chemometric method, a developed calibration model that was based on the spectral region between 1800 and 1480 cm^?1 was shown to be able to predict the PV in oxidized emulsions over the range of 4–45 meq/kg. With a ‘leave‐one‐out’ cross‐validation optimization procedure, the calibration model provides a good coefficient of determination of 0.98 and a root mean standard error of cross‐validation of 2.09. In general, FTIR spectroscopy is a suitable technique to monitor PV in oxidized emulsions.     

Graft copolymerization of methyl methacrylate onto oil palm empty fruit bunch fiber using H2O2/Fe2+ as an initiator

Graft copolymerization of methyl methacrylate (MMA) onto oil palm empty fruit bunch fiber (OPEFB) was successfully carried out in aqueous medium using hydrogen peroxide as an initiator. Results from the investigation of the optimum conditions for grafting are presented. Maximum percentage of grafting was achieved when the amount of initiator, cocatalyst, and nitric acid were 5.877 × 10^?3 mol, 2.63 × 10^?4 mol, and 3.24 × 10^?3 mol, respectively. The optimum reaction temperature was 50°C and the reaction period was 120 min. The highest percentage of grafting and grafting efficiency were 220 and 47%, respectively, under optimum conditions. The grafted copolymer was characterized by FTIR spectroscopy and scanning electron microscopy. The presence of a band at 1730 cm^?1 provides strong evidence of grafting. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2233–2238, 2003     

Botnet detection techniques: review,future trends,and issues

In recent years, the Interact has enabled access to widespread remote services in the distributed computing environment; however, integrity of data transmission in the distributed computing platform is hindered by a number of security issues. For instance, the botnet phenomenon is a prominent threat to Intemet security, including the threat of malicious codes. The botnet phenomenon supports a wide range of criminal activities, including distributed denial of service （DDoS） attacks, click fraud, phishing, malware distribution, spam emails, and building machines for illegitimate exchange of information/materials. Therefore, it is imperative to design and develop a robust mechanism for improving the botnet detection, analysis, and removal process. Currently, botnet detection techniques have been reviewed in different ways; however, such studies are limited in scope and lack discussions on the latest botnet detection techniques. This paper presents a comprehensive review of the latest state-of-the-art techniques for botnet detection and figures out the trends of previous and current research. It provides a thematic taxonomy for the classification of botnet detection techniques and highlights the implications and critical aspects by qualitatively analyzing such techniques. Related to our comprehensive review, we highlight future directions for improving the schemes that broadly span the entire botnet detection research field and identify the persistent and prominent research challenges that remain open.     

Review:Botnet detection techniques: review,future trends,and issue

In recent years, the Internet has enabled access to widespread remote services in the distributed computing environment; however, integrity of data transmission in the distributed computing platform is hindered by a number of security issues. For instance, the botnet phenomenon is a prominent threat to Internet security, including the threat of malicious codes. The botnet phenomenon supports a wide range of criminal activities, including distributed denial of service(DDoS) attacks, click fraud, phishing, malware distribution, spam emails, and building machines for illegitimate exchange of information/materials. Therefore, it is imperative to design and develop a robust mechanism for improving the botnet detection, analysis, and removal process. Currently, botnet detection techniques have been reviewed in different ways; however, such studies are limited in scope and lack discussions on the latest botnet detection techniques. This paper presents a comprehensive review of the latest state-of-the-art techniques for botnet detection and figures out the trends of previous and current research. It provides a thematic taxonomy for the classification of botnet detection techniques and highlights the implications and critical aspects by qualitatively analyzing such techniques. Related to our comprehensive review, we highlight future directions for improving the schemes that broadly span the entire botnet detection research field and identify the persistent and prominent research challenges that remain open.     

Wide range electrostatic MEMS Fabry Perot optical tunable filter: modelling an electrostatic and mechanic beam deflection

A novel wide range electrostatic microelectromechanical system floating Fabry Perot optical tunable filter (MEMS f-FPOTF) is modelled and analyzed in terms of its electro-mechanic behaviour. The composite beam approach has been used to model the floating Fabry Perot cavity. The floating dual membrane FPOTF consists of multi layer Si/SiO₂/Si thin films with an optical cavity in the middle structure. The filter tuning range has been improved by utilizing bonded silicon on insulator wafers that permits the floating cavity to be deflected both ways; up and down. Electro-mechanic analysis shows a 7% (STRUCTURE1) and 5% (STRUCTURE2) difference between analytical and finite element modelling in which the 7% difference in light incident angle contributes to a 0.5 nm shift while the 5% difference in length of cavity indicates a 4 nm shift in MEMS f-FPOTF operating wavelength. This analysis validates the analytical modelling of this device as a wavelength selector in coarse wavelength division multiplexing.     

An appraisal and design of a multi-agent system based cooperative wireless intrusion detection computational intelligence technique

The deployment of wireless sensor networks and mobile ad-hoc networks in applications such as emergency services, warfare and health monitoring poses the threat of various cyber hazards, intrusions and attacks as a consequence of these networks’ openness. Among the most significant research difficulties in such networks safety is intrusion detection, whose target is to distinguish between misuse and abnormal behavior so as to ensure secure, reliable network operations and services. Intrusion detection is best delivered by multi-agent system technologies and advanced computing techniques. To date, diverse soft computing and machine learning techniques in terms of computational intelligence have been utilized to create Intrusion Detection and Prevention Systems (IDPS), yet the literature does not report any state-of-the-art reviews investigating the performance and consequences of such techniques solving wireless environment intrusion recognition issues as they gain entry into cloud computing. The principal contribution of this paper is a review and categorization of existing IDPS schemes in terms of traditional artificial computational intelligence with a multi-agent support. The significance of the techniques and methodologies and their performance and limitations are additionally analyzed in this study, and the limitations are addressed as challenges to obtain a set of requirements for IDPS in establishing a collaborative-based wireless IDPS (Co-WIDPS) architectural design. It amalgamates a fuzzy reinforcement learning knowledge management by creating a far superior technological platform that is far more accurate in detecting attacks. In conclusion, we elaborate on several key future research topics with the potential to accelerate the progress and deployment of computational intelligence based Co-WIDPSs.     

Structural,optical and electrical properties of Ce0.8Sm0.2-xErxO2-δ (x = 0–0.2) Co-doped ceria electrolytes

This study examined the effects of samarium and erbium co-doping on the structural, optical, and electrical properties of ceria (CeO₂). Ceramic (Ce_0.8Sm_0.2-xEr_xO_2-δ; x?=?0, 0.05, 0.10, 0.15, 0.20) electrolytes were synthesized via sol-gel assisted citric acid–nitrate combustion and calcined at 850?°C for 5?h. The calcined electrolytes possessed a cubic fluorite crystal structure without impure phases. The direct band gap of the calcined electrolytes increased as the erbium content increased and the lowest band gap was obtained for Ce_0.8Sm_0.2O_2-δ (SDC) electrolyte. The calcined electrolyte powders were subsequently pressed into cylindrical pellets by uniaxial die pressing, and the pellets were sintered at 1400?°C for 5?h. The sintered densities of the pellets were measured with Archimedes’ method. The relative density of Ce_0.8Sm_0.1Er_0.1O_2-δ co-doped ceria electrolyte was higher than those of singly doped ones, and these findings were further confirmed through field emission scanning electron microscopy. Electrochemical impedance spectroscopy indicated that the conductivity of erbium-doped ceria increased as the samarium content increased. The maximum total ionic conductivity was observed in Ce_0.8Sm_0.1Er_0.1O_2-δ co-doped electrolyte. However, the singly doped SDC electrolyte exhibited the highest ionic conductivity of 13.12 mS/cm and the lowest activation energy of 0.580?eV at 600?°C among all other Ce_0.8Sm_0.2-xEr_xO_2-δ co-doped ceria electrolytes.     

Optimization of the Stack Unit in a Thermoacoustic Refrigerator

ABSTRACT

A thermoacoustic refrigerator is a device that uses acoustic power to pump heat in the absence of harmful refrigerants with no or few moving parts. However, the performance of the thermoacoustic refrigerator, particularly the standing wave types, is currently not competitive compared to its counterpart, the conventional vapor-compression refrigerator. Presently, thermoacoustic refrigeration prototypes only achieved 0.1–0.2 relative coefficient of performance, compared with that of 0.33–0.5 for the conventional vapor-compression refrigerators. Past optimization efforts had been completed based on parametric studies where individual parameters are discretely varied and the final optimized outcome was based on the limited series of numerical/experimental tests. This paper discusses the initial investigation of the optimization of the thermoacoustic refrigerator stack parameters using a multi-objective genetic algorithm. The desired outputs, the maximization of the cooling load and the minimization of the acoustic power at the stack, are obtained with the parameters to be optimized set within some range of values. The stack length and center position are then optimized simultaneously. The optimized results showed that the coefficient of performance of the thermoacoustic refrigerator improves from the published value of 1.3 to 1.37.     

Integrating ecosystem services in Swedish environmental assessments: an empirical analysis

Given the growing number of policies and laws that encourage inclusion of ecosystem services (ES) in processes, we have investigated environmental impact assessments (EIA) and strategic environmental assessments (SEA) conducted in Sweden in order to analyse whether ES may be integrated to enhance and improve environmental assessment of today. Representative Swedish environmental projects were reviewed. Three cases with different geographic and environmental settings were selected to allow us to study consideration of a wide range of different ES. We investigated the processes and discussions taking place using documentation from the cases. We formalized and labelled the expected impacts into an ES framework. Summarizing each case, we described conformities and divergences in explicit and implicit prioritizations between the actors. We discussed the benefits of integrating ES into current practices and possible improvements in the processes and methodologies. When ES could be integrated into EIAs and SEAs more aspects would be visualized and a larger stakeholder engagement stimulated leading to improved support for decision-making.     

Antioxidative Properties of <Emphasis Type="Italic">Curcuma longa</Emphasis> Leaf Extract in Accelerated Oxidation and Deep Frying Studies

The antioxidative properties of Curcuma longa (turmeric) leaf extract were evaluated in refined, bleached and deodorized (RBD) palm olein using accelerated oxidation and deep frying studies at 180 °C for up to 40 h. The extract was capable of retarding oil oxidation and deterioration significantly (P < 0.05) at 0.2% concentration, better than 0.02% BHT for the Oxidative Stability Index (OSI) in an accelerated oxidation study and also the peroxide value in deep frying studies. In sensory evaluation, the French fries were acceptable and were not significantly different (P < 0.05) from one another for color, oiliness and crispiness throughout the 40-h frying study. Curcuma longa leaf extract, which had a polyphenol content of 116.3 ± 0.2 mg/g, possessed heat-stable antioxidant properties and may be a good natural alternative to existing synthetic antioxidants in the food industry.