A note on leapfrogging vortex rings

In this paper we provide examples, by numerical simulation using the Navier-Stokes equations for axisymmetric laminar flow, of the 'leapfrogging' motion of two, initially identical, vortex rings which share a common axis of symmetry. We show that the number of clear passes that each ring makes through the other increases with Reynolds number, and that as long as the configuration remains stable the two rings ultimately merge to form a single vortex ring

Quantitative infrared thermography resolved leakage current problem in cathodic protection system

Leakage current problem can happen in Cathodic Protection (CP) system installation. It could affect the performance of underground facilities such as piping, building structure, and earthing system. Worse can happen is rapid corrosion where disturbance to plant operation plus expensive maintenance cost. Occasionally, if it seems, tracing its root cause could be tedious. The traditional method called line current measurement is still valid effective. It involves isolating one by one of the affected underground structures. The recent methods are Close Interval Potential Survey and Pipeline Current Mapper were better and faster. On top of the mentioned method, there is a need to enhance further by synthesizing with the latest visual methods. Therefore, this paper describes research works on Infrared Thermography Quantitative (IRTQ) method as resolution of leakage current problem in CP system. The scope of study merely focuses on tracing the root cause of leakage current occurring at the CP system lube base oil plant. The results of experiment adherence to the hypothesis drawn. Consequently, res

Maternal child feeding knowledge and practices and growth status of young children aged 6 to 24 months in Kuala Lumpur

This study was conducted to determine the association between maternal child feeding knowledge and practices with the growth status of young children. A total of 102 young children (62 boys and 40 girls) aged between 6 and 24 months old and their mothers participated in this study. A set of structured questionnaire; was used to obtain information on socio-economic, demographic characteristics, maternal feeding knowledge and practices, and anthropometric measurements of the young children. Maternal feeding knowledge was assessed in three different constructs i.e. general nutrition, breastfeeding and complementary feeding. Maternal feeding practice was assessed by examining whether mothers met the WHO guidelines for continued breastfeeding or feeding of milk or milk products, number of feeding times and number of food groups. Anthropometric measurements of the children such as weight and recumbent length were obtained using TANITA weighing scale and wooden measuring board, respectively. The anthropometric measurements were then compared to the National Center for Health Statistics (NCHS) reference. The results indicated that 18.6% (n=19) of the young children were significantly underweight, 16.7% (n=17) mildly underweight, and 3.9% (n=4) were overweight. The percentage of children with significant and mild wasting were 17.6% (n=18) and 32.4% (n=33) respectively, while 14.7% (n=15) and 34.3 (n=35) were significantly and mildly stunted respectively. Maternal feeding data showed that the mean of maternal feeding knowledge score in the three constructs were 6.73±0.18, 5.97±0.19 and 6.57±0.18, for general nutrition, breastfeeding and complementary feeding respectively. The total score for each construct was 10. The mean total knowledge score obtained was 19.26±4.12. Maternal feeding practice data indicated that 97.1% (n=99) of the mothers continued breastfeeding or feeding milk or milk products, 33.3% (n=34) of the children were fed the recommended minimum number of times, and 81.4% (n=83) of the children were fed the recommended minimum number of food groups. Statistical test on the association between maternal child feeding knowledge and practices with the growth status of young children will be further conducted. Maternal nutritional knowledge and child feeding practices should not be overlooked as factors that may influence growth status of young children

An investigation on polymeric blend mixed matrix membranes of polyethersulfone/polyvinyl acetate/carbon molecular sieve for CO2/Ch4 separation

Polymeric membranes have been vastly used for gas separation purposes however they have an upper-bound trade off problem which is the reason why this research work is focusing on inorganic filler added to polymer blend membranes to enhance the selectivity and permeability of the resulted membranes. Different percentages (5, 10 and 15 wt.%) of carbon molecular sieve (CMS) were added to a blend of polyethersulfone/polyvinyl acetate (PES/PVAc) (90/10) to produce polymeric blend mixed matrix membranes (PB3M) by solvent evaporation method. These membranes were characterized by field emission scanning electron microscopy (FESEM) to find out the membrane morphology and then their gas separation performance was assessed using high purity CO2 and CH4 gases. Addition of CMS to the blend of this glassy and rubbery polymer, increased the CO2/CH4 selectivity and CO2 permeability of the resulted PB3Ms. The highest selectivity which was 43.26 was achieved at 10 bar and at room temperature by adding 15% CMS to the polymer blend membrane.Keywords: Mixed Matrix membrane; polyvinyl acetate; polyethersulfone; carbon molecularsiev

Caesarean Risk Factors in Northern Region of Bangladesh: A Statistical Analysis

Purpose: To explore the measurement of a scale of caesarean (C-section) risk factors and degree of risk contribution in different health facilities and to determine a suitable graphical representation (image) of caesarean cases.Methods: Based on seventeen indicators, a composite index was computed for each respondent and classified into three groups using Beta distribution of first kind. For the analysis of contribution of risk factors between private and public patients, principal component analysis (PCA) was also used. An attempt was made to visualise a suitable graphical representation of caesarean cases by independent component analysis (ICA).Results: The selected risk factors were more contributory to public hospital patients than to those in private hospitals on the basis of higher estimated value of range (R = 0.134) but a higher proportion of C-section occurred in private (93.4 %) than in public hospitals (30.3 %). On the other hand, PCAshowed that the contribution of selected risk factors accounts for approximately 60.0 % and 68.5 % in private and public hospitals, respectively. Furthermore, from the various graphical representation, thenumbers of private patients were more interlinked by ICA but not of the other graphical representations of PCA.Conclusion: We had expected the rate of C-section would be higher among public hospital patients than private hospital patients but the results obtained indicate the reverse. It seems that the combination of the propensity of private practice doctors to carry out C-section and the financial benefits on the part of private hospitals may be contributory factors to the caesarean section rates in private health facilities.Keywords: Caesarean risk factors, Composite index, Principal component analysis (PCA), Independent component analysis (ICA)

User perception of information credibility of news on Twitter

In this paper, we examine user perception of credibility for news-related tweets. We conduct a user study on a crowd-sourcing platform to judge the credibility of such tweets. By analysing user judgments and comments, we find that eight features, including some that can not be automatically identified from tweets, are perceived by users as important for judging information credibility. Moreover, distinct features like link in tweet, display name and user belief consistently lead users to judge tweets as credible. We also find that users can not consistently judge or even misjudge the credibility for some tweets on politics news

Microfinance: Viable Approaches for Islamic Banking Implementation

Islamic banks have very much engaged in debt financing businesses the same way and as much as their conventional counterparts do. Debt financing businesses, as widely implemented, were specifically targeted for and tailored to the needs of middle and upper income group of people. The low income people remain left out and forgotten in most banking businesses while microfinance instruments, which are meant to help the poor and needy, remain unpopular among the banking institutions. There is indeed increasing calls for Islamic banks to seriously consider this type of instrument as part of their religious obligation embedded under their Islamic identity. This paper demonstrated that microfinance instruments are viable for Islamic banks to consider despite the claims that the contracts are less secured and hence, too risky to embark in. A number of microfinance instruments based on Islamic concepts namely Musyarakah, Murabahah, Mudharabah, Ijarah and Qard al-Hassan as well as operational frameworks such as SPV and wakalah, were being proposed and discussed to pave ways for its implementation by the Islamic banks

On the correlation of theory and experiment for transversely isotropic nonlinear incompressible solids

A novel strain energy function for finite strain deformations of transversely isotropic elastic solids which is a function five invariants that have immediate physical interpretation has recently been developed. Three of the five invariants are the principal stretch ratios and the other two are squares of the dot product between the preferred direction and two principal directions of the right stretch tensor. A strain energy function, ex- pressed in terms of these invariants, has a symmetrical property almost similar to that of an isotropic elastic solid written in terms of principal stretches. This constitutive equation is attractive if principal axes techniques are used in solving boundary value problems and experimental advantage is demonstrated by showing a simple triaxial test can vary a single invariant while keeping the remaining invariants fixed. Explicit expressions for the weighted Cauchy response functions are easily obtained since the response function basis is almost mutually orthogonal. In this paper a specific form of the strain energy function for incompressible materials which is linear with respect to its physical parameters is developed. When a curve fitting method is (sensibly) applied on an experimental data, the values of the parameters are obtained uniquely via a linear positive definite system of equations. The theory compares well with experimental data and the performance of the proposed specific form is discussed. A constitutive inequality, which may reasonably be imposed upon the material parameters, is discussed

Correlation analysis of reader's demographics and tweet credibility perception

When searching on Twitter, readers have to determine the credibility level of tweets on their own. Previous work has mostly studied how the text content of tweets in uences credibility perception. In this paper, we study reader demographics and information credibility perception on Twitter. We nd reader's educational background and geolocation have signi cant correlation with credibility perception. Further investigation reveals that combinations of demographic attributes correlating with credibility perception are insigni cant. Despite di erences in demographics, readers nd features regarding topic keyword and the writing style of a tweet to be independently helpful in perceiving tweets' credibility. While previous studies reported the use of features independently, our result shows that readers use combination of features to help in making credibility perception of tweets