201 research outputs found
Experimental design using response surface methods for palm olein-based hydroxy-ether systhesis
Hydroxy-ether-POo was synthesised via alcoholysis reaction of epoxidized palm olein (EPOo). The experimental design was conducted using response surface methodology (RSM) based on 3 factors; reaction time, reaction temperature and catalyst loading. Responses such as percentage of conversion and percentage of yield were determined using statistical software ‘Design Expert 9’. Hydroxy-ether-POo showed the presence of proton peak attached to the carbon of ether (3.2, 3.5 ppm) and proton of the hydroxyl (4.8 ppm). The presence of carbon peak bonded to hydroxyl was detected at chemical shift 75 ppm and carbonyl carbon of ether at 72 ppm
Sintesis sebatian hidroksi-eter minyak sawit olein
Sebatian hidroksi-eter-POo (80% hasil) disintesis melalui pembukaan gelang oksirana minyak sawit olein terepoksida (EPOo) secara alkoholisis. Hasil optimum pembukaan gelang oksirana (99.2%) dicapai dengan menggunakan asid sulfurik 3% v/bt pada suhu tindak balas yang tinggi (80oC) selama 30 minit masa tindak balas. Spektrum resonan magnetik nukleus-proton (1H-NMR) hidroksi-eter-POo telah menunjukkan kehadiran puncak proton pada karbon eter (3.2, 3.5 ppm) dan proton pada kumpulan hidroksil (4.8 ppm). Spektrum resonan magnetik nukleus-karbon (13C-NMR) hidroksi-eter-POo telah menunjukkan kehadiran puncak karbon yang terikat dengan kumpulan hidroksil (75 ppm) dan karbon pada karbonil kumpulan eter (72 ppm). Kelikatan kinematik hidroksi-eter-POo adalah 234.4 cSt (40oC) dan 28.1 cSt (100oC) dengan indeks kelikatan 156
Effects of cadmium chloride on some endocrine glands (thyroid and adrenal) in male rats (Rattus norvegicus)
This study was designed to evaluate the cytotoxic effects of cadmium chloride (CdCl2) on thyroid and adrenal gland of male rats (Rattus norvegicus). Thirty six male rats were used and randomly into three groups each of 12 rats, the first group(G1) kept as at control. The 2nd and 3rd groups (G2 and G3) were administrated orally cdcl2 at doses of 15 and 20 mg/kg.B.W. respectively for 6 weeks. After the treatment period, the rats were sacrificed, then thyroid and adrenal glands were removed and processed for light microscope. Light microscopic examination of thyroid gland with (15mg/kg.B.W.) showed increase in the size of follicles, some of these follicles appeared empty from any colloidal substance and heavily infiltrated by inflammatory cells, with depletion of parafollicular cells. Vaculated follicles may be clear in other sections, and showed congested blood vessels, vascularized stroma, hyperplasia of thyrocyte in rats treated with 20 mg/kg.B.w. Results also noted changes in different regions of adrenal gland related to rats exposure tocdcl2 with 15 mg/kg.B.W., these includes cellular debris, necrosis of cortical cells, amorphous material in the zona fasciculate and focal necrosis in zona granulosa with disruption of normal structure and replaced by necrotic cells and inflammatory cells, also obvious adipocytes infiltration which appeared clear in medulla. Most changes occurred within the adrenal cortex and appeared more severity than that in the medulla region. Hypereosinophilia, pyknotic nuclei, congested blood vessels, hemorrhage, degeneration and inflammation also seen in both regions (cortex and medulla) of adrenal gland from rat exposed to cdcl2 at 20 mg/kg.B.W
Optimization of response surface methodology by D-optimal design for alkaline hydrolysis of crude palm kernel oil
Crude palm kernel oil (CPKO) was converted into its free fatty acids (FFAs) via alkaline hydrolysis. The reaction optimization was performed using Response Surface Methodology (RSM) through D-optimal design to optimize the conducted hydrolysis parameters. The optimization parameters were varied from 1.5 to 2.5 h of reaction time, 50-70°C of reaction temperature, and ethanolic KOH concentration 1-2 M. The highest percentage of free fatty acids was 98 ± 0.7 % with a percentage fatty acid yield of 84.7 ± 0.6 % under optimal conditions, which were 2.16 h of reaction time, 1.77 M ethanolic KOH concentration, and 70°C reaction temperature. High-temperature Capillary Column Gas Chromatography (GC-FID) and Nuclear Magnetic Resonance-Fourier Transform Infrared Spectroscopy (NMR-FTIR) were employed to characterize the product. The physicochemical properties of fatty acids were also tested. The acid value, iodine value, and hydroxyl value of the fatty acids obtained were 275.4 ± 0.7 mg NaOH/g, 21.8 ± 0.2 g I2 / 100 g, and 168.2 ± 0.1 mg KOH/g, respectively
Mutual Solubility of MEG, Water and Reservoir Fluid: Experimental Measurements and Modeling using the CPA Equation of State
A Novel Architectural Framework on IoT Ecosystem, Security Aspects and Mechanisms: A Comprehensive Survey
For the past few years, the Internet of Things (IoT) technology continues to not only gain popularity and importance, but also witnesses the true realization of everything being smart. With the advent of the concept of smart everything, IoT has emerged as an area of great potential and incredible growth. An IoT ecosystem centers around innovation perspective which is considered as its fundamental core. Accordingly, IoT enabling technologies such as hardware and software platforms as well as standards become the core of the IoT ecosystem. However, any large-scale technological integration such as the IoT development poses the challenge to ensure secure data transmission. Perhaps, the ubiquitous and the resource-constrained nature of IoT devices and the sensitive and private data being generated by IoT systems make them highly vulnerable to physical and cyber threats. In this paper, we re-define an IoT ecosystem from the core technologies view point. We propose a modified three layer IoT architecture by dividing the perception layer into elementary blocks based on their attributed functions. Enabling technologies, attacks and security countermeasures are classified under each layer of the proposed architecture. Additionally, to give the readers a broader perspective of the research area, we discuss the role of various state-of-the-art emerging technologies in the IoT security. We present the security aspects of the most prominent standards and other recently developed technologies for IoT which might have the potential to form the yet undefined IoT architecture. Among the technologies presented in this article, we give a special interest to one recent technology in IoT domain. This technology is named IQRF that stands for Intelligent Connectivity using Radio Frequency. It is an emerging technology for wireless packet-oriented communication that operates in sub-GHz ISM band (868 MHz) and which is intended for general use where wireless connectivity is needed, either in a mesh network or point-to-point (P2P) configuration. We also highlighted the security aspects implemented in this technology and we compare it with the other already known technologies. Moreover, a detailed discussion on the possible attacks is presented. These attacks are projected on the IoT technologies presented in this article including IQRF. In addition, lightweight security solutions, implemented in these technologies, to counter these threats in the proposed IoT ecosystem architecture are also presented. Lastly, we summarize the survey by listing out some common challenges and the future research directions in this field.publishedVersio
Robust hovering controller for uncertain multirotor micro aerial vehicles (MAVS) in gps-denied environments: IMAGE-BASED
This paper proposes an image-based robust hovering controller for multirotor micro aerial vehicles (MAVs) in GPS-denied environments. The proposed controller is robust against the effects of multiple uncertainties in angular dynamics of vehicle which contain external disturbances, nonlinear dynamics, coupling, and parametric uncertainties. Based on visual features extracted from the image, the proposed controller is capable of controlling the pose (position and orientation) of the multirotor relative to the fixed-target. The proposed controller scheme consists of two parts: a spherical image-based visual servoing (IBVS) and a robust flight controller for velocity and attitude control loops. A robust compensator based on a second order robust filter is utilized in the robust flight control design to improve the robustness of the multirotor when subject to multiple uncertainties. Compared to other methods, the proposed method is robust against multiple uncertainties and does not need to keep the features in the field of view. The simulation results prove the effectiveness and robustness of the proposed controller
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