Monoclinic bismuth oxide (α-Bi2O3) nanoparticles were prepared via precipitation method and
irradiated with a pulsed laser forming thin films. Their phase and surface morphological properties
were investigated using x-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron
microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM). The XRD
analysis shows the phase transformation to a partially crystalline tetragonal phase β-Bi2O3 thin film.
The SEM micrograph of the nanoparticles, with an average crystal size of 72 nm, was seen to form
a thin film with a peculiar structure, coined as “cotton-like”, is attributed to the high surface energy
absorbed by the nanoparticles during ablation. The HR-TEM micrograph shows the particulate with
a clearly defined interlayer spacing.
One of the ways to calculate dividend for an investment is by using average lowest balance (ALB) concept. The existing calculation of dividend based on ALB concept can only be done yearly. This paper discusses on the development of a general formula to calculate the accumulated amount for any period of time, based on the ALB concept that considers different yearly dividend rates. The patterns for each variable and coefficient for the calculated yearly accumulated amount were analysed. The general forms of each variable and coefficient were then combined to form the general formula for calculating the accumulated amount. Validity of the general formula is confirmed by calculating the percentage errors and proven by using mathematical induction.
Feature selection has been widely applied in many areas such as classification of spam emails, cancer cells, fraudulent claims, credit risk, text categorisation and DNA microarray analysis. Classification involves building predictive models to predict the target variable based on several input variables (features). This study compares filter and wrapper feature selection methods to maximise the classifier accuracy. The logistic regression was used as a classifier while the performance of the feature selection methods was based on the classification accuracy, Akaike information criteria (AIC), Bayesian information criteria (BIC), Area Under Receiver operator curve (AUC), as well as sensitivity and specificity of the classifier. The simulation study involves generating data for continuous features and one binary dependent variable for different sample sizes. The filter methods used are correlation based feature selection and information gain, while the wrapper methods are sequential forward and sequential backward elimination. The simulation was carried out using R, an open-source programming language. Simulation results showed that the wrapper method (sequential forward selection and sequential backward elimination) methods were better than the filter method in selecting the correct features.
Over the last few years, the Android smartphone had faced attacks from malware and malware variants, as there is no effective commercial Android security framework in the market. Thus, using machine learning algorithms to detect Android malware applications that can fit with the smartphone resources limitations became popular. This paper used state of the art Deep Belief Network in Android malware detection. The Lasso is one of the best interpretable ℓ1-regularisation techniques which proved to be an efficient feature selection embedded in learning algorithm. The selected features subset of Restricted Boltzmann Machines tuned by Harmony Search feature reduction with Deep Belief Network classifier was used, achieving 85.22% Android malware detection accuracy.
The purpose of this study is to investigate the effectiveness of Ficus deltoidea (F. deltoidea) as an antioral ulcer on animal models. Adult male Sprague Dawley rats were sedated with Nembutal through intraperitoneal route; oral ulcer models were made by applying 99.5% of glacial acetic acid moistened paper disc on rat buccal mucosa. Four groups of these rats were treated respectively with: no treatment (group 1: negative control); Triamcinolone acetonide (group 2: positive control); 250 mg kg-1 F. deltoidea extract (group 3: experimental); 500 mg kg-1 F. deltoidea extract (group 4: experimental) for 10 consecutive days, respectively. On days 2, 4, 6, 8 and 10, the ulcers size was assessed. Data was analysed statistically by using SPSS. The negative control rats exhibited buccal mucosa injury whereas treatment with F. deltoidea and Triamcinolone acetonide resulted in significantly reduced size of oral ulcer. The percentage of inhibitory area of oral ulcer was more prominent in 500 mg kg-1 F. deltoidea extract than 250 mg kg-1. Meanwhile, in vivo study showed that F. deltoidea extract not toxic up to 1000 mg kg-1. The present findings suggest that F. deltoidea extract effectively accelerates oral ulcer healing process, and could therefore be developed as a therapeutic agent for healing oral ulcer.
This paper focuses on examining the ‘cutting zone temperature’ while performing turning operation
on AZ91Mg alloy using cemented carbide tools. The regression model is developed by using the RSM
techniques based on experimental results. It is revealed that the cutting speed (v) is the most dominant
factor affecting cutting zone temperature. The developed models of cutting zone temperature sufficiently
map within the range of the turning conditions considered. The adequacy and accuracy of the regression
equation is justified through ANOVA. It is found that the optimal combinations of machining parameters
minimize the cutting temperature.
Multimode multiband connectivity has become a de-facto requirement for smartphones with 3G
WCDMA/4G LTE applications. In transceivers, multiband operation is achieved by selecting an output from two or more signal path targeting for a specific frequency range in parallel or by using switched capacitor/inductor. In this paper, design methodology of 280nm CMOS switch is presented. Design optimization of RF CMOS switch is presented which is deciding proper selection of CMOS transistor parameters and switch size as per external circuit parameters. The CMOS switch of a 5-transistor stack with W/L=1200μm/280nm provides insertion loss < 0.6dB and isolation loss >14dB. The switches designed when implemented in a multiband power amplifier (PA) exhibits 36dB gain at 1900MHz high-band and 34.5dB gain at 900MHz low-band with 27.5dBm peak power at both bands. The switch design methodologies presented in this paper should be of use in designing various blocks in emerging multiband transceiver applications.
Cloud Computing provides a solution to enterprise applications in resolving their services at all level of Software, Platform, and Infrastructure. The current demand of resources for large enterprises and their specific requirement to solve critical issues of services to their clients like avoiding resources contention, vendor lock-in problems and achieving high QoS (Quality of Service) made them move towards the federated cloud. The reliability of the cloud has become a challenge for cloud providers to provide resources at an instance request satisfying all SLA (Service Level Agreement) requirements for different consumer applications. To have better collation among cloud providers, FLA (Federated Level Agreement) are given much importance to get consensus in terms of various KPI’s (Key Performance Indicator’s) of the individual cloud providers. This paper proposes an FLASLA Aware Cloud Collation Formation algorithm (FS-ACCF) considering both FLA and SLA as major features affecting the collation formation to satisfy consumer request instantly. In FS-ACCF algorithm, fuzzy preference relationship multi-decision approach was used to validate the preferences among cloud providers for forming collation and gaining maximum profit. Finally, the results of FS-ACCF were compared with S-ACCF (SLA Aware Collation Formation) algorithm for 6 to 10 consecutive requests of cloud consumers with varied VM configurations for different SLA parameters like response time, process time and availability.
Wind energy has often been touted as one of the most reliable sources of renewable energy that should be used for people. Today, wind energy (mainly by propeller type wind turbines) produces less than one percent of the total energy used worldwide. Practically, a standard three-blade propellers efficiency of use of the wind energy is around twenty percents and this is due to its design and shape that use the wind lift force and a rotating turbine. In addition, these turbines are quite expensive due to the complex aerodynamic shape of the propellers which are made of composite materials. The new world boom for wind turbines obliges inventors to create new wind turbine designs that have high efficiency and are better than any known design. This paper proposes the new patented invention of the vane-type wind turbine which uses wind energy more efficiently and is only dependent on the acting area of the vanes. The vane wind turbine was designed to increase the output of a wind turbine that uses kinetic energy of the wind. Due to its high efficiency, simple construction and technology, the vane wind turbine can be used universally, apart from the fact that it is made from cheap materials. The new design of the vane-type wind turbine has quite small sizes than the propeller type one of same output power.
Doppler ultrasound is used in obstetrics and gynecology fields to serve as the complement
mode in the standard prenatal scan. It aids in investigating fetus blood flow in expectant
mothers’ wombs, usually those who come with pregnancy complications. In the conventional
ultrasound beam, the heat produced by attenuation is distributed over the area. However, the
Doppler ultrasound beam is focused at only one point. This leads the heat to accumulate at
that particular area and hence there is an increase in the temperature. Heat is considered as
a teratogen in pregnancy, whereby an increase in the fetal temperature can be fatal to the
fetus. Studies have found that Doppler mode is associated with higher acoustic output as
compared to the conventional two-dimensional (2D) ultrasound mode. Several studies done
on animals have ruled out the evidence of Doppler ultrasound bioeffects. This narrative
review only discusses the thermally induced effect of ultrasound by using Doppler mode.
This study reviews prior studies with keywords such as Doppler ultrasound, bioeffects,
heating effects, rabbit, and pregnancy. Earlier studies noted that the risk of thermal effects
increased with the increase of exposure time. However, Doppler ultrasound wave inducing
fetal hyperthermia is not the main reason for
causing adverse neonatal outcomes without
taking into account other external factors.
Therefore, it is essential for the practitioners
to adopt and adapt the concept of ‘as low as
reasonably achievable’ (ALARA) to avoid
any subtle adverse effects.
Vapor cloud explosion is one of the major threats to Floating, Production, Storage and Offloading (FPSO) facilities due to its congested and confined nature. Reduction in explosion overpressure can be achieved by improving the ventilation in FPSO. During early design stage of FPSO, designers consider providing grated process decks to improve the ventilation. However, there is limited research on the comparison of the explosion overpressure between the grated deck and the traditional plated deck. In this study, Vapor Cloud Explosion perspective of plated versus grated process deck in typical FPSO was evaluated by utilizing Det Norske Veritas’s (DNV) SAFETI OFFSHORE modelling tool. Representative leak scenarios were selected based on frequency analysis of major accident hazards associated with typical FPSO facility. This study revealed that the overpressure exceedance frequency in plated process deck was higher than the grated process deck for the selected scenario. This serves as quantitative guidance for designers to select an inherently safer type of decks in FPSOs from explosion perspective during the preliminary design stage. However, a detailed Computational Fluid Dynamics (CFD) study is recommended to get an insight of dangers associated with the presence of plated and grated process decks in FPSO, by considering all the parameters and conditions applicable.
In this paper, a mathematical model is developed based on mass and momentum balance for carbon dioxide absorption into aqueous ammonia solution. The model is simplified based on the assumption that the CO2 absorption into aqueous ammonia is a pseudo-first-order reaction. Laplace transform method is applied in order to solve the partial differential model equation. Finally, the CO2 molar flux is expressed as a function of partial pressure of CO2, concentration of aqueous ammonia, temperature and gas-liquid contact area. Variation of CO2 molar flux with partial pressure of CO2 and temperature is discussed and a comparison is performed with experimental data from literature. Variation of CO2 molar flux is also shown with gas-liquid contact area. The calculated flux from the model follows the same trend as that of the experimental data reported in literature and the accuracy is within the accepted limit. The mathematical model is very helpful to predict the CO2 molar flux as a function of partial pressure of CO2, concentration of aqueous ammonia, temperature and gas-liquid contact area.
In recent years image acquisition in close range photogrammetry relies on digital sensors such as digital cameras, video cameras, CCD cameras etc that are not specifically designed for photogrammetry. This study is performed to evaluate the compatibility of the digital metric camera and non-metric camera for the purpose of mapping meandering flume, using close range photogrammetric technique and further, to determine the accuracy that could be achieved using such a technique. The meandering flume provides an opportunity to conduct an experimental study in a controlled environment. In this study, the digital images of the whole meandering flume were acquired using a compact digital camera - Nikon Coolpix S560, a Single Lens Reflex (SLR) Nikon D60 and also a metric digital camera Rollei D30. A series of digital images were acquired to cover the whole meandering flume. Secondary data of ground control points (GCP) and check points (CP), established using the Total Station technique, was used. The digital camera was calibrated and the recovered camera calibration parameters were then used in the processing of digital images. In processing the digital images, digital photogrammetric software was used for processes such as aerial triangulation, stereo compilation, generation of digital elevation model (DEM) and generation of orthophoto. The whole process was successfully performed and the output produced in the form of orthophoto. The research output is then evaluated for planimetry and vertical accuracy using root mean square error (RMSE). Based on the analysis, sub-meter accuracy is obtained. It can be concluded that the differences between the different types of digital camera are small . As a conclusion, this study proves that close range photogrammetry technique can be used for mapping meandering flume using both the metric digital camera and non-metric digital camera.
Pre-stressing is a concept used in many engineering structures. In this study prestressing in the form of axial compression stress is proposed in the blade structure of H-Darrieus wind turbine. The study draws a structural comparison between reference and prestressed configurations of turbine rotor with respect to their dynamic vibrational response. Rotordynamics calculations provided by ANSYS Mechanical is used to investigate the effects of turbine rotation on the dynamic response of the system. Rotation speed ranging between 0 to 150 rad/s was examined to cover the whole operating range of commercial instances. The modal analysis ends up with first six mode shapes of both rotor configurations. As a result, the displacement of the proposed configurations reduced effectively. Apparent variations in Campbell diagrams of both cases indicate that prestressed configuration has its resonant frequencies far away from turbine operation speeds and thus remarkably higher safety factor against whirling and probable following failures.
Renewable energy projects in many developing countries need financial and legal back up from
governments and other supportive bodies. There is a viable alternative to finite energy via usage of
biomass waste a renewable energy source. The electrical energy production analysis on biomass waste
presented in this paper is based on the experimental analysis carried out using the laboratory and pilot
scale bioreactors. Electrical energy generated with oscillatory flow bioreactor (OFBR) was 10.12 kWh or
up to 91% higher than the 10 L lab scale bioreactor (0.9 kWh), demonstrating that the novel OFBR has a
great potential for renewable electricity. Also, the pilot scale plant achieves a value of 12.3 kWh, which
the difference is not quite significant with that of OFBR. These results illustrate that the generation of
the renewable electricity is feasible especially with the OFBR thereby achieving high methane potential
during the treatment of manure and food waste. Nevertheless, energy recoveries should be enhanced to
improve the entire operational performance.
The present investigation deals with the development of ethanol-vapour-sensing materials coated with the semiconducting oxide TiO2. Thick films of anatase TiO2 were deposited using the sol-gel dip-coating technique on alumina substrates by conventional alkoxide sol and modified sol added with Degussa P-25 as the sensing medium. It was shown that crystallised TiO2 anatase was obtained at the annealing temperature of 500oC. The fabricated TiO2 sensors exhibited highest sensitivity at the sensing temperature of 350 ºC. Sensitivity towards the ethanol vapour was further increased with UV light effect. The enhancement of the sensitivity of the modified catalytic pellet can be explained by the crystallite of anatase TiO2 and the effect of the photocatalytic of TiO2. The high sensitivity of the TiO2 film deposited with modified sol revealed that the modified sol could be a new alternative in the development of a TiO2 ethanol sensor.
Activin proteins are members of the transforming growth factor-β family. Activin A is involved in several biological responses including wound repair, cell death, proliferation and differentiation of many cell types. Biologically active activins consist of homodimers or heterodimers of two beta (β) subunits that are linked together by a single covalent disulphide bond. The subunits in humans are βA, βB, βC and βE. As an example, a combination of two βA subunits will produce a unit of activin A. These proteins are found in most cells of body such as macrophage and activated circulating monocytes. Their role in inflammation can be categorised into two types, either pro- or anti-inflammatory agents, depending on the cell type and phase. Activin signals are kept in balance by antagonist follistatin (Fst), which is a glycoprotein expressed in tissues and encoded by the follistatin gene in humans.
Inflammation and endothelial dysfunction are key components in atherogenesis. Should the status of these pro-atherogenesis factors be enhanced during prolonged confined space travel, specific countermeasures need to be instituted to prevent these processes to ensure safe outcome for astronauts during space expeditions. Six crew members were exposed to prolonged, confined isolation for 520 days. Standard exercise and diet regime were instituted throughout isolation phase. Age and gender-matched healthy, free living controls were recruited in parallel. Serial serum and whole blood were analysed for biomarkers of inflammation (hsCRP and IL-6) and endothelial activation (sICAM-1, sVCAM-1 and E-selectin). Flow-mediated dilatation (FMD) of the artery was performed following the standard protocols set by the International Brachial Artery Reactivity Task Force by trained personnel. There was decreased sVCAM-1 concentration in crew members compared to baseline. However, there was significant decrease in percentage dilatation from baseline in FMD of the brachial artery in the crew members. Percent change increment was observed in hsCRP while percent change reduction was seen in sVCAM-1. The enhanced inflammation and reduced endothelial function could possibly be attributed to the rigorous exercise instituted throughout the confinement period. Furthermore, possible haemoconcentration as a result of psychosocial stress and/ or exercise-induced physiological response could further explain elevations in hsCRP, and unlikely pathological. Furthermore, endothelial activation was attenuated during isolation, suggesting that the diet and exercise program instated throughout the period improved endothelial function.
Malaysia is a tropical country and it is subjected to flooding in both the urban and rural areas. Flood
modelling can help to reduce the impacts of flood hazard by taking extra precautions. HEC-RAS model was used to predict the flood levels at selected reach of the Langat River with a total length of 34.4 km. The Langat River is located in the state of Selangor, Malaysia and it is subjected to regular flooding. The selected reach of the Langat River has insufficient data and a methodology was proposed to overcome this particular problem. Since complete floodplain data for the area are not available, the modelling therefore assumed vertical walls at the left and right banks of the Langat River and all the predicted flood levels above the banks were based on this assumption. The HECRAS model was calibrated and the values of Manning’s coefficients of roughness for the Langat River were found to range from 0.04 to 0.10. The discharge values were calculated for 5, 10, 25, 50, and 100 year return periods and the maximum predicted flood depth ranged from 2.1m to 7.8m. Meanwhile, the model output was verified using the historical record and the error between the recorded and predicted water levels was found to range from 3% to 15%.
Strength and durability are important characteristics of concrete and desired engineering properties. Exposure to aggressive environment threatens durability of concrete. Previous studies on bio-concrete using several types of bacteria, including sulphate reduction bacteria (SRB), had to increase durability of concrete have shown promising results. This study used mixtures designed according to concrete requirement for sea water condition with SRB composition of 3%, 5% and 7% respectively. The curing time were 28, 56 and 90 days respectively. The mechanical properties, namely compressive strength and water permeability, were tested using cube samples. The results showed compressive strength had higher increase than the control at 53.9 Mpa. The SRB with 3%composition had maximum water permeability. Thus, adding SRB in concrete specimens improves compressive strength and water permeability. This is particularly suitable for applications using chloride ion penetration (sea water condition) where corrosion tends to affect durability of concrete constructions.