Dynamics of variable-viscosity nanofluid flow with heat transfer in a flexible vertical tube under peristaltic waves

The present investigation addresses nanofluid flow and heat transfer in a vertical tube with temperature-dependent viscosity. A Tiwari-Das type formulation is employed for the nanofluid with a viscosity modification. The transport equations are transformed from a cylindrical coordinate system with appropriate variables and simplified via longwave length and low Reynolds number approximations. The resulting boundary value problem is solved analytically. The influence of heat source/sink parameter (), Grashof number (Gr) and the viscosity parameter () and nanoparticle volume fraction () on velocity, temperature, pressure gradient, pressure rise and wall shear stress distributions is presented graphically. Three different nanofluid suspensions are investigated- Titanium oxide-water, Copper oxide-water and Silver-water. Streamline plots are also computed to illustrate bolus dynamics and trapping phenomena which characterize peristaltic propulsion. The computations show that wall shear stress is maximum for the Silver-water nanofluid case. Furthermore the pressure rise is reduced with increasing Grashof number, heat absorption parameter and viscosity parameter in the augmented pumping region whereas the contrary response is observed in the peristaltic pumping region. Significant modification in the quantity of trapped boluses is found with different nanofluids and the size of the trapped bolus is decreased in the Titanium oxide-water nanofluid case with either greater heat source or sink parameter. The study is relevant to drug delivery systems exploiting nano-particles

INTERNAL COMMUNICATION CHALLENGES AND ISSUES: A CASE STUDY OF TRANSNET FREIGHT RAIL BUSINESS UNIT COAL, VRYHEID (KWAZULU NATAL PROVINCE, SOUTH AFRICA)

Abstract Internal communication is a relatively new field of research, particularly within Transnet Freight Rail. Therefore, the purpose of this research was to investigate the internal communication challenges and issues of Transnet Freight Rail Bu Coal Vryheid. Three major themes were considered within the field of internal communication: internal communication management, the channels utilised within organisation for internal communication and whether measurement of the internal communication was evident. The findings indicate that internal communication is a large area of research that differs between organisations with content, structure and management. Additionally, a range of communication channels were used in all of the participant departments with emails the most predominant channel, while face-to-face communication was an often underutilised channel. One finding was the lack of formal measurement undertaken by the company, thereby contradicting the advisement of the academic literature. It was recommended that management specifically corporate affairs measure internal communication by conducting an internal communication audit. Face-to-face communication should be encouraged, there should be organised more meetings between different divisions/departments, people must realise that the division's cooperation brings more effectiveness to everybody's work; things are done faster, easier and better

Rheological effects of micropolar slime on the gliding motility of bacteria with slip boundary condition

The gliding organisms are phylogenetically diverse with their hundreds of types, different shapes and several mechanism of motility. Gliding bacteria are rod-shaped bacteria without any flagella on their surface. They exhibit a creeping type of self-powered motion when nearly in contact with a solid surface. These bacteria leave an adhesive trail of slime and propel themselves by producing undulating waves in their body, which is one possible mode of motility for gliding bacteria. In the present study an undulating surface model is considered to discuss this type of bacterial locomotion. The classical Navier-Stokes equations are incapable of explaining the slime rheology at the microscopic level. Micropolar fluid dynamics however provides a solid framework for mimicking bacterial physical phenomena at both micro and nano-scales, and therefore in the present study, the constitutive equations of micropolar fluid are implemented to characterize the rheology of the slime. The flow equations are formulated under long wavelength and low Reynolds number assumptions. Exact expressions for stream function and pressure gradient are obtained. The speed of the gliding bacteria is numerically calculated by using a modified Newton-Raphson method. In addition, when the glider is fixed, the effects of micropolar slime parameters on the velocity, micro-rotation (angular velocity) of spherical slime particles, pressure rise per wavelength, pumping and trapping phenomena are also shown graphically and discussed in detail. The study is relevant to emerging biofuel cell technologies and also bacterial biophysics

A multicentre matched case control study of risk factors for Preeclampsia in healthy women in Pakistan

<p>Abstract</p> <p>Background</p> <p>Preeclampsia is one of the leading causes of maternal and perinatal morbidity and mortality world-wide. The risk for developing preeclampsia varies depending on the underlying mechanism. Because the disorder is heterogeneous, the pathogenesis can differ in women with various risk factors. Understanding these mechanisms of disease responsible for preeclampsia as well as risk assessment is still a major challenge. The aim of this study was to determine the risk factors associated with preeclampsia, in healthy women in maternity hospitals of Karachi and Rawalpindi.</p> <p>Methods</p> <p>We conducted a hospital based matched case-control study to assess the factors associated with preeclampsia in Karachi and Rawalpindi, from January 2006 to December 2007. 131 hospital-reported cases of PE and 262 controls without history of preeclampsia were enrolled within 3 days of delivery. Cases and controls were matched on the hospital, day of delivery and parity. Potential risk factors for preeclampsia were ascertained during in-person postpartum interviews using a structured questionnaire and by medical record abstraction. Conditional logistic regression was used to estimate matched odds ratios (ORs) and 95% confidence intervals (95% CIs).</p> <p>Results</p> <p>In multivariate analysis, women having a family history of hypertension (adjusted OR 2.06, 95% CI; 1.27-3.35), gestational diabetes (adjusted OR 6.57, 95% CI; 1.94 -22.25), pre-gestational diabetes (adjusted OR 7.36, 95% CI; 1.37-33.66) and mental stress during pregnancy (adjusted OR 1.32; 95% CI; 1.19-1.46, for each 5 unit increase in Perceived stress scale score) were at increased risk of preeclampsia. However, high body mass index, maternal age, urinary tract infection, use of condoms prior to index pregnancy and sociodemographic factors were not associated with higher risk of having preeclampsia.</p> <p>Conclusions</p> <p>Development of preeclampsia was associated with gestational diabetes, pregestational diabetes, family history of hypertension and mental stress during pregnancy. These factors can be used as a screening tool for preeclampsia prediction. Identification of the above mentioned predictors would enhance the ability to diagnose and monitor women likely to develop preeclampsia before the onset of disease for timely interventions and better maternal and fetal outcomes.</p

Beyond misfortune and fault : Islam, same-sex sexuality and liberation

M.A. (Semitic Languages and Cultures)The aim of this dissertation is to analyse some of the prominent elements that constitute the discussion of same-sex sexuality among Muslims such as the distinction between sexual acts and identities and its effect on the construction of sexuality in Muslim societies, the religious and legal permissibility of particular sexual acts, and the intersection between the struggle for justice and equality and sexuality. The theoretical framework for this study is based on postcolonialism and queer theory. I argue that a fundamental rethinking of sex and sexuality in Islam and in Muslim societies needs to transpire in order for a more equitable state of affairs to come into existence. The current prejudice associated with same-sex sexuality requires a considered and erudite overhaul of how sexual relationships and gender are constructed in Islamic ethics and Muslim societies. I first consider the effect of sexual identities, namely a homosexual identity, and the consideration of same-sex sexual acts on the Muslim imagination. The notion of unnatural sexual impulses, sinful desires and the interrelationship between various sexual crimes are important considerations in the discourse on sexual diversity among Muslims. Second, I critically assess the argument in favour of same-sex marriages in Islam based on the assumption of stable identities and the inherent righteousness of a human rights framework. I assess the legal tools used set out some of the challenges of the human rights discourse which influences the struggle for homosexual rights and raise some question as to the efficacy of this strategy or mode of resistance and acceptance. Third, I focus on the nexus between sexual diversity, secularism and empire as sites of contestation and collaboration that continue to influence articulations and constructions of how to be Muslim and be also part of a sexual minority. Fourth, I attempt to chart a way forward for queer Muslims and argue in favour of protecting the conceptual and social space of the ‘closet’ as a liberatory and protective domain for queer Muslims where it is possible to balance both the demands of one’s faith and the expression of one’s sexuality

Book Review: Islamic Law and Muslim Same-Sex Unions

Book Title: Islamic Law and Muslim Same-Sex UnionsBook Authors: Junaid Jahangir &amp; Hussein AbdallatifLanham: Lexington Books 2016. ISBN: 978-0-7391-8937-5