Development of compact antenna for RFID application

In recent years, microstrip antennas have met commercial requirements. The advent of wireless applications requires a compact antenna, easy to manufacture. The goal of the project is to develop a microstrip monopole antenna for RFID tag applications that reduce size. The purpose of this antenna is to operate at 2.4 GHz. Due to its low-profile, a microstrip monopole antenna was chosen as a design model for the project.CST Microwave studio 2015 has been used to simulate the design of antennas for preliminary design purposes. This can be recognized as being unique to the advantages of the antenna. . The proposed antenna was etched on an FR4 substrate with an overall size of 40 mm × 17 mm × 1.6 mm. The successful implementation of the modified ground plane allows the miniaturization and provides excellent performance. The performance of an antenna shows agreement between both simulation and measurement results

Experimental and computational fluid dynamics (CFD) studies of gas-liquid flow in bends

Within the oil industry there is a need to measure and predict the form of the multiphase liquid and gas flows that are present within oil production and processing pipelines. Knowledge of the flow regimes present allows the engineer to optimise the configuration of the pipeline and downstream processes to achieve the most, economic and reliable design. The applications of these technologies are collectively known as flow assurance. Within oil production systems, one component which has received little attention is the characterisation of the multiphase flow around bends under various process conditions. To predict the flow regimes in greater details requires the development of instrumentation that can measure and characterise the flow within the pipes. To circumvent this challenge, two experimental investigations were carried out in two rigs available in the Chemical and Environmental Engineering Laboratories at the University of Nottingham. These are: (1) a 67 mm internal diameter pipe joined to a 90o bend, in which air/silicone oil flows were investigated using advanced instrumentation: Electrical Capacitance Tomography (ECT), Wire Mesh Sensor Tomography (WMS), and high-speed video. The first two provide time and cross-sectionally resolved data on void fraction. The ECT probes were mounted 10 diameters upstream of the bend whilst the WMS was positioned either immediately upstream or immediately downstream of the bend. The downstream pipe was maintained horizontal whilst the upstream pipe was mounted either vertically or horizontally. The bend (R/D = 2.3) was made of transparent acrylic resin. The superficial velocities of the air ranged from 0.05 to 4.73 ms-1 and for the silicone oil from 0.05 to 0.38 ms-1. (2) a 127 mm internal diameter riser joined to a vertical 180o bend, in which measurements of film fraction and liquid film thickness distribution for an air-water system were obtained using the electrical conductance technique. The former was measured using the ring conductance probes placed 17 and 21 diameters, respectively upstream and downstream of the bend, 45o, 90o and 135o within the bend. The latter were obtained using pin and parallel wire probes. The pin probes were used for thin films measurement whilst the parallel wire probes for thick films. The bend, made of transparent acrylic resin, has a curvature ratio (R/D = 3). The superficial velocities of the air ranged from 3.5 to 16.1 ms-1 and for the water from 0.02 to 0.2 ms-1. The experimental results for the 90o bend study reveal that bubble/spherical cap bubble, slug, unstable slug and churn flows were observed before the bend for the vertical pipe and plug, slug, stratified wavy and annular flows when the pipe was horizontal. Bubble, stratified wavy, slug, semi-annular and annular flows are seen after the bend for the vertical 90o bend, the flow patterns remained the same as before the horizontal 90o bend. These results were confirmed by the high-speed videos taken around the bend. For the vertical 180o return bend, the average film fraction was identified to be higher in straight pipes than in bends. For low liquid and higher gas flow rates, due to the action of gravity drainage, film breakdown occurs at the 45o bend. A previously proposed criterion, to determine stratification after the 90o bend, based on a modified Froude number have been shown to be valid for a liquid different from that tested in the original paper. Similarly, for the 180o return bend, the condition for which the liquid goes either to the inside or outside of the bend are identified based on published material. Variations between average liquid film thickness and bend angles are reported for the vertical 180o bend. Contrary to the conclusions reached by Hills (1973) and Anderson and Hills (1974), the liquid film thickness becomes annular flow in the 180o bend at low liquid flow rates and stratified flow at higher liquid superficial velocities. In addition, a CFD code has been used to successfully model the hydrodynamics of the slug flow pattern in a riser and vertical 90o bend, using the Volume of Fluid model based on the Eulerian approach, implemented in the commercial CFD package Star-CCM+. The modelling results are validated with the experiments and also provide more detailed information on the flow such as the velocity field

Cytological screening and Seroincidence of IgM with possible risk factors associated with naturally selected high risk group for Oncogenic Human Papilloma Virus Infection in Daura, Katsina State

Cervical cancer is the second most common cancer among women in the developing countries and the seventh commonest cancer in the developed countries. Human papillomavirus (HPV) is now known to be the main factor in the aetiology of cervical cancer with over 99.7% of cases being associated with previous high risk HPV infection. The aim of the research is to determine the risk factors and incidence of oncogenic human papilloma virus among women of reproductive age in Daura. This was a cross-sectional prospective study involving a total of 120 women. Questionnaires were administered to collect data such as socio-demographic and possible risk factors. Endocervical swab and serum samples were then collected from the participants. Samples were analyzed by Enzyme Linked immunosorbent Assay and Pap smear respectively. The findings of this research revealed and overall high seroincidence of 36.6% as well as significant difference between seroincidence rate of pregnant and non-pregnant women. The findings also revealed that 10-20 age groups had the higher seroincidence rate of (50.0%) with no statistical significant difference between age groups. None of the sociodermographic factors involved in the research show significant association with HPV infections. The result by type of marriage shows that similar seroincidence rate was obtained in both monogamy and polygamy forms of marriage (36.7%). The study also reveals that risk factors like sexual partners, HIV status and sexual debut are significantly associated with HPV infection (P<0.05). Sixty (60) participants show normal cytole under microscope with prevalence of 50.0% and those with abnormal cytole had prevalence of (16.7%) while lowest prevalence of (3.3%) was obtained from participants with high squamous intraepithelial lesions. These results demonstrate a high seroincidence of HPV infection among women in the study area. We recommend improved education regarding HPV and cervical cancer among the populace and increasing cervical cancer screening particularly to attendees of antenatal care to prevent HPV related morbidity and mortality. Keywords: HPV; Cervical cancer; Endocervical swab; Seroincidenc

Entrepreneurial and Market Orientation Relationship to Performance: The Role of Business Environment

The purpose of the study is to examine the moderating effects of business environment on the relationship between entrepreneurial orientation (EO), market orientation (MO) and business performance of small and medium enterprises (SMEs) in Nigeria. This study seeks to resolve the inconsistencies found in the contemporary literature concerning the relationship between EO, MO and business performance. A planned questionnaire using a 5-point Likert scale was adopted from previous works to determine the respondents’ response. A survey research design was adopted and self - administered questionnaires were used to collect the data from 640 owner/managers of SMEs. The analysis was carried using SPSS version 20, the results of the study indicated that entrepreneurial orientation has a significant and positive relationship with business performance; a negative relationship is reported between market orientation and business performance. The study also found that business environment does not moderate the relationship between entrepreneurial orientation, market orientation and business performance of SMEs. Owner/ managers, regulatory agencies, government, and other stakeholders will benefit from the study findings, and future research direction provided. Keywords: Entrepreneurial orientation, Market orientation, Business Environment, Business Performance, SMEs

The Effect of Liquid Viscosity on the Rise Velocity of Taylor Bubbles in Small Diameter Bubble Column

The rise velocity of Taylor bubbles in small diameter bubble column was measured via cross-correlation between two planes of time-averaged void fraction data obtained from the electrical capacitance tomography (ECT). This was subsequently compared with the rise velocity obtained from the high-speed camera, manual time series analysis and likewise empirical models. The inertia, viscous and gravitational forces were identified as forces, which could influence the rise velocity. Fluid flow analysis was carried out using slug Reynolds number, Froude number and inverse dimensionless viscosity, which are important dimensionless parameters influencing the rise velocity of Taylor bubbles in different liquid viscosities, with the parameters being functions of the fluid properties and column diameter. It was found that the Froude number decreases with an increase in viscosity with a variation in flow as superficial gas velocity increases with reduction in rise velocity. A dominant effect of viscous and gravitational forces over inertia forces was obtained, which showed an agreement with Stokes law, where drag force is directly proportional to viscosity. Hence, the drag force increases as viscosity increases (5 < 100 < 1000 < 5000 mPa s), leading to a decrease in the rise velocity of Taylor bubbles. It was concluded that the rise velocity of Taylor bubbles decreases with an increase in liquid viscosity and, on the other hand, increases with an increase in superficial gas velocity

Slug length for high viscosity oil-gas flow in horizontal pipes: experiments and prediction

An experimental investigation was carried out on the effects of high liquid viscosities on slug length in a 0.0762-m ID horizontal pipe using air-water and air-oil systems with nominal viscosities ranging from 1.0 to 5.5 Pa s. The measurements of slug length were carried out using two fast sampling gamma densitometers with a sampling frequency of 250 Hz. The results obtained show that liquid viscosity has a significant effect on slug length. An assessment of existing prediction models and correlations in the literature was carried out and statistical analysis against the present data revealed some discrepancies, which can be attributed to fluid properties in particular, low viscous oil data used in their derivation Hence, a new high viscous oil data presented here from which we derive a new slug length correlation was derived using dimensional analysis. The proposed correlation will improve prediction of slug length as well as provide a closure relationship for use in flow simulations involving heavy oil. This is important since most current fields produce highly viscous oil with some reaching 10 Pa s

Molecular diagnosis of urinary Mycobacterium tuberculosis among patients attending urology clinic in Aminu Kano Teaching Hospital, Kano, Nigeria

Background: Tuberculosis, a communicable disease with significant morbidity and mortality. It is still among the top killers of infectious diseases; Mycobacterium tuberculosis is a successful pathogen that has evolved several mechanisms to manipulate the host immune response. Objective of the study: The objective of this study was to determine the prevalence of urinary tuberculosis among patients attending urology clinic in Aminu Kano Teaching Hospital, Kano, Nigeria. Materials and Methods: A prospective cross-sectional laboratory based study that involved the use of questionnaire and consent/assent form prior to sample collection. Xpert MTB/Rif assay was used to analyze the urine samples. Results: The results of this study shows that, out of 71 samples analyzed along with positive control (H37RV) and molecular grade water was used as negative control. The results showed that, 2 (2.8 %) were from urine samples. Data generated were analyzed using descriptive statistics and results were presented in tables and charts. Conclusion: The study confirmed the presence of urinary tuberculosis in the study area, with prevalence of 2.8%. The pattern of tuberculosis was susceptible Mycobacterium tuberculosis. Therefore, there is need to introduce a routine screening of urinary tuberculosis among patients presenting sign and symptoms of urinary tract infection using Gene Xpert. This will be achieved through the engagement and enlightenment of the clinicians, strengthening the laboratory capacity for diagnosis and make the services available and accessible to the patients who need them. Keywords: Mycobacterium tuberculosis; Extra-Pulmonary Tuberculosis; Prevalence and Gene Xpert

The Emergence of Anisotropic Superconductivity in the Nodal-line Semi-metal TlTaSe2

TlTaSe2 is a non-centrosymmetric quasi-2D crystal semi-metal hosting nodal-line topological features protected by mirror-reflection symmetry. Here, we investigated the superconducting properties of TlTaSe2 using the first-principles anisotropic Migdal-Eliashberg theory. The Fermi surface hosts well gapped multiband features contributed by the Ta 5d and Tl 6p orbitals. Moreso, anisotropic superconducting gaps were found to exist at 2.15 and 4.5 meV around the in-plane orbitals, coupling effectively with the in-plane phonons of the Ta and Tl atoms. Using the Allen-Dynes-modified McMillan formula, we found a superconducting transition temperature of 6.67 K, accompanied by a robust electron-phonon coupling constant {\lambda} of 0.970. This investigation provides valuable insights into the mechanisms underlying anisotropic superconductivity in TlTaSe2.Comment: 17 pages, 5 figure

Comparative analysis of riser base and flowline gas injection on vertical gas-liquid two-phase flow

Gas injection is a frequently used method for artificial lift and flow regime rectification in offshore production and transportation flowlines. The flow behaviour in such flowlines is complex and a better understanding of flow characteristics, such as flow patterns, void fraction/hold up distributions and pressure gradient is always required for efficient and optimal design of downstream handling facilities. Injection method and location have been shown to strongly affect downstream fluid behaviour that can have important implications for pumping and downstream facility design, especially if the development length between pipeline and downstream facility is less than L/D = 50 as reported by many investigators. In this article, we provide the results of an experimental investigation into the effects of the gas injection position on the characteristics of the downstream upwards vertical gas flow using a vertical riser with an internal diameter of 52 mm and a length of 10.5 m. A horizontal 40-m-long section connected at the bottom provides options for riser base or horizontal flow line injection of gas. The flowline gas injection is performed 40 m upstream of the riser base. A 16 by 16 capacitance wire mesh sensor and a gamma densitometer were used to measure the gas-liquid phase cross-sectional distribution at the riser top. A detailed analysis of the flow characteristics is carried out based on the measurements. These include flow regimes, cross-sectional liquid holdup distributions and peaking patterns as well as analysis of the time series data. Our findings show that flow behaviours differences due to different gas injection locations were persisting after a development length of 180D in the riser. More specifically, core-peaking liquid holdup occurred at the lower gas injection rates through the flowline, while wall-peaking holdup profiles were established at the same flow conditions for riser base injection. Wall peaking was associated with dispersed bubbly flows and hence non-pulsating as against core-peaking was associated with Taylor bubbles and slug flows. Furthermore, it was found that the riser base injection generally produced lower holdups. It was noted that the circumferential injector used at the riser base promoted high void fraction and hence low liquid holdups. Due to the bubbly flow structure, the slip velocity is smaller than for larger cap bubbles and hence the void fraction is higher. The measurements and observations presented in the paper provides valuable knowledge on riser base/flowline gas introduction that can directly feed into the design of downstream facilities such as storage tanks, slug catchers and separators

Persistence of frequency in gas–liquid flows across a change in pipe diameter or orientation

From a study of the characteristics of structures across a 67/38 mm sudden contraction, using air/silicone oil flows, it has been found that frequencies of the structures (mainly slugs) persist across the contraction. This is in contrast to the velocities and lengths which increase as they move into the smaller diameter pipe. These observations were found for both vertical and 5° upward orientations. A similar persistence of frequency has been found from four other sources in the literature: a vertical (gradual) contraction; a horizontal Venturi; and two cases of horizontal pipe, 90° bend and vertical riser combination. The latter were at two contrasting conditions: (i) at atmospheric pressure with air/water in small diameter (34 mm) pipes; (ii) at 20 bar in larger diameter pipes (189 mm) using nitrogen and naphtha