Dvali-Gabadadze-Porrati Cosmology in Bianchi I brane

The dynamics of Dvali-Gabadadze-Porrati Cosmology (DGP) braneworld with an anisotropic brane is studied. The Friedmann equations and their solutions are obtained for two branches of anisotropic DGP model. The late time behavior in DGP cosmology is examined in the presence of anisotropy which shows that universe enters a self-accelerating phase much later compared to the isotropic case. The acceleration conditions and slow-roll conditions for inflation are obtained

DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR THE SIMULTANEOUS ESTIMATION OF ALISKIREN HEMIFUMARATE AND VALSARTAN IN BULK AND PHARMACEUTICAL DOSAGE FORM

Objective: A new, simple, selective, and reproducible stability indicating reversed - phase high performance liquid chromatography method for thesimultaneous estimation of Aliskiren (ALN) Hemifumarate and Valsartan (VLN) in bulk drug, and tablet dosage form was developed and validated asper ICH guidelines.Methods: The chromatographic separation was performed using a nucleosil C - 18 column and the analytes were detected by a malondialdehyde - 2010photodiode array detector. The mobile phase composed of methanol: potassium dihydrogen ortho phosphate buffer (adjusted to pH 3 withorthophosphoric acid). The flow rate was set at 1 ml/minutes, and the detection was carried out at 225 nm.Results: ALN Hemifumarate and VLN showed a retention time of 3.84 and 5.96 minutes, respectively. The linear dynamic range was found to be5-50 mcg/ml and 5-30 mcg/ml with a co-relation co-efficient of 0.992 and 0.985 for ALN and VLN, respectively, with mean percentage recoveries of99.95% and 99.25%. The results were validated and were found to successfully obey the parameters as per ICH guidelines.Conclusion: Hence, the method can be successfully applied for routine quality control analysis and stability studies for both ALN Hemifumarate andVLN in bulk and tablet dosage form as per regulatory requirements.Keywords: Aliskiren Hemifumarate, Valsartan, Reversed-phase high performance liquid chromatography, Stress degradation study, ICH guidelines

STABILITY INDICATING ANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF MEMANTINE HCl AND DONEPEZIL HCl USING RP-HPLC

Objective: To develop and validate stability indicating method for the analysis of Memantine HCl and Donepezil HCl.Methods: The chromatographic separation was performed on Hypersil BDS (4.6 x 150 mm, 5m) using Sodium dihydrogen ortho phosphate: Acetonitrile (30:70v/v) at a flow rate of 1 ml/min and detection of both the eluents was carried out by UV Detector.Results: The Retention time of Memantine HCl and Donepezil HCl were found to be 2.833 min. and 4.777 min respectively. Method was found to be linear over the range of 40-120μg/ml for Memantine HCl and 20-60μg/ml for Donepezil HCl. Percentage recovery of Memantine HCl and Donepezil HCl was found to be 99.62% and 99.45% respectively. The percentage purity thus found is 98.5% and 98.6% for Memantine HCl and Donepezil HCl. The Limit of Detection of Memantine HCl and Donepezil HCl is 3.69 mg/ml and 2.72 mg/ml. and Limit of Quantification of Memantine HCl and Donepezil HCl is 11.13 mg/ml and 8.25 mg/ml respectively. In the stress degradation studies, it was found that Memantine HCl and Donepezil HCl showed no degradation in acid (0.1M HCl), base (0.1M NaOH), peroxide, heat and sunlight.Conclusion: A new sensitive, simple, and stability indicating high performance layer chromatographic (HPLC) method has been developed and validated for determination of Memantine HCl and Donepezil HCl. The proposed method can be used for routine determination of Memantine HCl and Donepezil HCl stability.Â

Bulk scalar field in DGP braneworld cosmology

We investigated the effects of bulk scalar field in the braneworld cosmological scenario. The Friedmann equations and acceleration condition in presence of the bulk scalar field for a zero tension brane and cosmological constant are studied. In DGP model the effective Einstein equation on the brane is obtained with bulk scalar field. The rescaled bulk scalar field on the brane in the DGP model behaves as an effective four dimensional field, thus standard type cosmology is recovered. In present study of the DGP model, the late-time accelerating phase of the universe can be explained .Comment: 10 pages, to appear in JCA

Challenges in compression testing of 3D angle-interlocked woven-glass fabric-reinforced polymeric composites.

This paper describes the challenges in using testing standards such as D6641/D6641M-14, for determination of compressive strength of 3D angle interlocked glass fabric reinforced polymeric composites (3D-FRPC). It makes use of both experimental investigation and finite element analysis. The experimental investigation involved testing both 2D and 3D-FRPC using ASTM D6641/D6641M-14 and subsequent scanning electron microscopic imaging of failed specimens to reveal the stress state at failure. This was further evaluated using laminate level finite element (FE) analysis. The FE analysis required input of effective orthotropic elastic material properties of 3D-FRPC, which were determined by customizing a recently developed micro-mechanical model. The paper sheds new light on compressive failure of 3D angle interlocked glass fabric composites, as only scarce data is available in literature about this class of materials. It showed that although the tests produce acceptable strength values the internal failure mechanisms change significantly and the standard deviation (SD) and coefficient of variance (COV) of 3D-FRPC comes out to be much higher than that of 2D-FRPC. Moreover, while reporting and using the test data some additional information about the 3D-fabric architecture, such as the direction of angle interlocking fabric needs to be specified. This was because, for 3D angle interlocking of fabric along warp direction, the strength values obtained in the warp and weft direction were significantly different from each other. The study also highlights that due to complex weave architecture it is not possible to achieve comparable volume fractions with 2D and 3D fabric reinforced composites using similar manufacturing parameters for the vacuum assisted resin infusion process. Thus, the normalized compressive strength values (normalized with respect to volume fraction) are the highest for 3D-FRPC when measured along the warp direction, they are at an intermediate level for 2D-FRPC and the lowest for 3D-FRPC, when measured in the weft direction.DelPHE 780 Project grant (DFID UK

Defect engineering for improved photocatalytic performance of reduced lead titanate (PbTiO3) under solar light irradiation

Lead titanate (PbTiO3) nanoparticles were prepared successfully by template free hydrothermal  method. Size, crystallinity, morphology and phase determination of the nanoparticles were made by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM). FESEM results had shown that all nanoparticles were in the range between 20 to 40 nm size and found in the form of agglomerates. The average crystallite size of PbTiO3 nanoparticles was calculated to be nearly 35 nm. PbTiO3 nanoparticles were reduced by hydrogenation at high temperature to make the material active for visible light. Furthermore, optical absorbance of PbTiO3 nanoparticles was determined by applying ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. By using Davis-Mott model, the direct optical band gap of 2.65 eV was acquired. Methyl orange (MO) was used as pollutant to check the photocatalytic activity of reduced PbTiO3 nanoparticles under solar light irradiation. Photocatalytic activity of reduced PbTiO3 nanoparticles increased 2.6 times more than that of pure PbTiO3 nanoparticles for methyl orange (MO) under solar light irradiation.               KEY WORDS: Lead titanate (PbTiO3), Photocatalytic performance, Hydrothermal growth, Solar light, Irradiation Bull. Chem. Soc. Ethiop. 2019, 33(2), 373-380.DOI: https://dx.doi.org/10.4314/bcse.v33i2.1

Band gap engineering for improved photocatalytic performance of CuS/TiO2 composites under solar light irradiation

ABSTRACT. Nanoparticles of CuS, TiO2 and CuS/TiO2 composites were prepared by template free hydrothermal method. Prepared nanoparticles were characterized by X-ray diffraction (XRD) and electron dispersive X-ray spectroscopy to confirm the formation of nanoparticles. Field emission scanning electron microscopy (FESEM) was applied to investigate the morphology and particle size of the nanoparticles which were measured in the range of 30–40 nm. Photocatalytic performance of CuS, TiO2 and Cus/TiO2 were measured by degradation of methyl orange (MO) under solar light irradiation. Coupling of n-type TiO2 (3.2 eV) with p-type CuS (1.9 eV) showed efficient degradation of the contaminants under the solar light irradiation. Photocatalytic performance of CuS/TiO2 composite improves 1.4 times than CuS for the degradation of methyl orange (MO) under solar light irradiation.               KEY WORDS: CuS/TiO2 composites, Photocatalytic performance, Hydrothermal growth, Solar light, Irradiation Bull. Chem. Soc. Ethiop. 2019, 33(3), 561-571.        DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

Intrusion Detection Framework for Industrial Internet of Things Using Software Defined Network

The Industrial Internet of Things (IIoT) refers to the employment of the Internet of Things in industrial management, where a substantial number of machines and devices are linked and synchronized with the help of software programs and third platforms to improve the overall productivity. The acquisition of the industrial IoT provides benefits that range from automation and optimization to eliminating manual processes and improving overall efficiencies, but security remains to be forethought. The absence of reliable security mechanisms and the magnitude of security features are significant obstacles to enhancing IIoT security. Over the last few years, alarming attacks have been witnessed utilizing the vulnerabilities of the IIoT network devices. Moreover, the attackers can also sink deep into the network by using the relationships amidst the vulnerabilities. Such network security threats cause industries and businesses to suffer financial losses, reputational damage, and theft of important information. This paper proposes an SDN-based framework using machine learning techniques for intrusion detection in an industrial IoT environment. SDN is an approach that enables the network to be centrally and intelligently controlled through software applications. In our framework, the SDN controller employs a machine-learning algorithm to monitor the behavior of industrial IoT devices and networks by analyzing traffic flow data and ultimately determining the flow rules for SDN switches. We use SVM and Decision Tree classification models to analyze our framework’s network intrusion and attack detection performance. The results indicate that the proposed framework can detect attacks in industrial IoT networks and devices with an accuracy of 99.7%

Enhanced clustering based routing protocol in vehicular ad‐hocnetworks

A vehicular ad‐hoc network (VANET) is derived from a mobile ad‐hoc network that is a part of less infrastructure network design. Vehicular communication in VANET can be achieved using vehicle‐to‐infrastructure (V2I) and vehicle‐to‐vehicle (V2V) communication. A vehicle communicates with other vehicles through onboard units while communicating with roadside units in an infrastructure mode. Secure clustering is required for the communication between nodes in the whole network. The fundamental problem with the VANET is the instability of the network that occurs due to vehicles' mobile nature, which decreases the network's efficiency. This research proposes an enhanced cluster‐based lifetime protocol ECBLTR that focuses on maximising the network's stability of routing and average throughput. The Sugeno model fuzzy inference system is used for assessing the cluster head (CH) that takes residual energy, local distance, node degree, concentration, and distance from the base station as input parameters. Our enhanced routing protocol shows that the proper channel model with an efficient routing protocol enhances the link throughput of the VANET for fixed network size. Our results show an efficient selection method of CH through the fuzzy system and a 10% increase in network lifetime. Furthermore, performance evaluation also demonstrates the impact of network sizes and routing protocols on packet delivery ratio and packet loss, average end‐to‐end delay, and overhead transmission