Modified water-cement ratio law for compressive strength of rice husk ash concrete

This work examines the modification of age long water – cement ratio law of Ordinary Portland Cement (OPC) concrete to cater for concrete with Rice Husk Ash (RHA). Chemical analysis of RHA produced under controlled temperature of 600°C was carried out. A total of one hundred and fifty (150) RHA concrete cubes at five different water/binder ratios and at six replacement levels of RHA (5%, 10%, 15%, 20%, 25%, 30%) were produced with specific attention given to cement/water (c/w) content and RHA/water (r/w) content. The cubes were subjected to compressive strength test at 56 days of curing producing a compressive strength in the range of 3.77 N/mm² to 34.04N/mm². A linear polynomial model was fitted into the experimental data using Minitab Package and was found adequate with an adjusted coefficient of determination of 73.0%.Test results show that the compressive strength of hardened RHA concrete depends on cement/water content by weight on one part and RHA/water content by weight on the other part. This indicates that the model equation is suitable to evaluate the compressive strength of RHA concrete at 95% confidence interval and the linear model has the capability of explaining the variability in the data by 73%.Keywords: water-cement ratio, compressive strength, rice husk ash, model

The role of biosensors and biological weapons in national defence and security operations

The knowledge of biotechnology plays an important role in the development of biological weapons. Biological weapons are considered an attractive factor in war for several reasons: ease of manufacture, low cost, confirmed injury, increased number of victims, large losses incurred by other countries. Biological weapons detection methods are among the most important means of military defense. Biological sensors are used in early detection of weapons. Biotechnology is of paramount importance in all fields of medicine, engineering, agriculture, industry, as well as military life. The key applications of biotechnology in the military are in the areas of sensor systems and systems for protection from espionage. Among the most important countries that have applied knowledge of bioweapons technology into their security system are the USA and China. Despite the enormous advantages of biotechnology, it has negative effects in biological weapon production. Therefore, the near future will witness a tremendous boom in biotechnology. DNA profiling also plays an important role in detection of crime. The overall aim of the review is to emphasize the importance of biotechnology towards solving bioterrorism and other forms of security challenges in an environment

Lessons learnt during the national introduction of human papillomavirus (HPV) vaccination programmes in 6 African countries: Stakeholders’ perspectives

Background. Infection with human papillomavirus (HPV) significantly increases the risk of developing cervical cancer later in life. Therefore, globally, HPV vaccines targeted to pre-adolescent and adolescent girls have been on the rise since the licensure in 2006. However, the introduction of HPV vaccines has been relatively slow in Africa. At the end of 2016, only 8 of the 54 countries in Africa were reported to have introduced HPV vaccination at a national level. By 2019, the number of countries had grown marginally to 11.Objectives. To investigate stakeholders’ perspectives on the experiences, challenges and lessons learnt during national HPV vaccine introduction in Africa.Methods. A questionnaire was administered to selected participants from 8 African countries. These countries had successfully introduced HPV vaccination at a national level by the end of 2016. We used in-depth interviews and self-administered online questionnaires for data collection and analysis. Data are presented without naming the country or participants; therefore, readers will not be able to identify the results that are specific to individual countries. Narrative and thematic reporting were used to describe the results.Results. We obtained results from 6 of the 8 targeted countries. The challenges reported during HPV vaccination programmes were: identifying the target population, using a school-based vaccine-delivery strategy, obtaining political support, the need to integrate HPV vaccination with existing school health programmes and engaging multiple stakeholders. These challenges were similar in all 6 countries. The lessons learnt were that a school-based delivery strategy is a successful approach for national HPV vaccination, and that identifying girls for vaccination at schools was less challenging if implemented through a class-based instead of an age-based approach.Conclusions. Most African countries do not have established platforms to deliver vaccines to pre-adolescent and adolescent populations. The successful introduction of the HPV vaccine through school-based vaccination strategies in African countries may have created a platform to deliver other adolescent vaccines. The similarity of the study findings across the 6 participating countries further strengthens the need to document and disseminate the challenges and lessons learnt during HPV vaccine introduction in Africa. Documentation and dissemination of the challenges and lessons learnt are useful to other countries in Africa that plan to introduce an HPV vaccination programme, and possibly other adolescent vaccines.

The Correlation Functions and Estimation of Global Solar Radiation Studies Using Sunshine Based Model for Kano, Nigeria

The use of empirical models for the comparative study of the correlation functions for the estimation of global solar radiation in Kano, Nigeria has been carried out. The models used are based on relative sunshine duration alongside the measured global solar radiation data, such as: the linear model..... More details can be found in the full paper

ARCHITECTURAL DESIGN AS A PREDICTOR OF PATRONAGE OF RECREATIONAL CENTRES IN KADUNA STATE, NIGERIA

The study assesses architectural design as a predictor of patronage of recreational centres in Kaduna State, Nigeria. One research questions were answered, and one hypothesis were formulated to guide this study. A descriptive survey research design was used for this study. The population for the study comprised all staff of recreational centres in Kaduna State, with a population of 3,249. Multistage sampling technique was used to select the sample for the study. Researcher developed questionnaire was used as the instrument for data collection and it was validated by 3 experts from the Department of Physical and Health Education, Faculty of Education, Bayero University, Kano. A pilot study was conducted and a reliability index of 0.87 was obtained. Out of 441 copies of questionnaire administered by the researcher and his assistants, 432 copies were duly completed, returned and analyzed. Frequency count and percentage were used to describe the demographic information of the respondents while Chi-square (χ2) statistics was used to test all the formulated hypotheses at the 0.05 alpha level of significant. The findings of this study revealed that power supply significantly influence the patronage of recreational centres in Kaduna state c2 = 140.08, df = 1, P < 0.05. It was recommended among others, that authorities such as ministry of tourism and culture should set up a board each to plan, execute and supervise the existing buildings in the recreational centres.  Article visualizations

Effect of Thickness on Structural and Electrical Properties of CuAlS2 Thin Films Grown by Two Stage Vacuum Thermal Evaporation Technique

This work studies the effect of thickness on structural and electrical properties of CuAlS2 thin films grown by two stage vacuum thermal evaporation technique. CuAlS2 thin films of thicknesses 50nm, 100nm and 200nm were deposited on suitably cleaned corning 7059 glass substrate at room temperature (RT). In the first stage Cu-Al precursors were grown at room temperature by thermal evaporation and in the second stage Cu-Al precursors were converted to CuAlS2 thin films by sulfurisation under sulfur atmosphere at the temperature of 673K. The structural properties of the films were examined by X-ray diffraction (XRD) technique while electrical properties of the specimens were studied using four point probe method. The XRD studies revealed that the films are of crystalline in nature having tetragonal structure. The variations of the micro-structural parameters, such as crystallite size (D), dislocation density ( ), and micro-strain ( ), with film thickness were investigated. The results showed that the crystallite sizes increase as the thickness of the film increases. The dislocation density and micro-strain decreases as the thickness increases. The resistivity (  ) of CuAlS2 film is found to decrease with increase in film thickness, which is related to the increase of carrier concentration with film thickness. Thus thicker films exhibit the lowest resistivity and high carrier concentration, implying these are the most conductive films. Low electrical resistivity and high carrier concentration are widely used as the essential components in various optoelectronic devices such as light-emitting diode and photovoltaic cells

Tuberculin screening of some selected Fulani lactating cows in north-central Nigeria

The prevalence of mycobacterial infection among lactating Fulani cows was investigated in the Federal Capital Territory, Abuja and Kaduna State of Nigeria. Tuberculin testing using single comparative intradermal tuberculin test showed a 14.6 % positive, 4 % doubtful, and 81.4 % negative reactors. Mycobacterial infection was found to be present in the nomadic (constantly moving) and seminomadic (limited movement) management systems studied but management showed no significant effect on the prevalence of the disease. However, the prevalence was significantly higher in older age groups than the younger ones (P < 0.05).Peer reviewedSubmitted Versio

DEMATEL-ANP risk assessment in oil and gas construction projects

Oil and gas construction projects are complex and risky because of their dynamic environment. Furthermore, rising global energy demand has increased the need for trustworthy risk assessment models for such projects that can provide adequate and precise policy planning. Traditional risk assessments in oil and gas construction projects do not consider the interrelationships of factors in the best-fit models. The Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Processes (ANP), called the DEMATEL-ANP approach, have been applied to other research disciplines to address this shortcoming. This method is able to construct a structural relationship among the different influence factors to visualize complex correlations. Thus, the purpose of this study is to showcase the DEMTAL-ANP risk assessment model to assess the overall risk factors of OGC projects. This study thus identifies the crucial risk criteria of such projects. Data were collected in 2016 through interviews with experts active in OGC projects in Iran. DEMATEL in this situation is used to determine the interdependencies' relative strengths among the risks. The ANP method is applied to assess the relative importance of the risk factors and to determine the best strategy for implementation of a risk management program. The results presented in this study are a novel adaptation of the risk assessment methodology to OGC projects that determines the important risk factors that directly affect the project success, which in turn helps in formulation of policies for ensuring reliable energy supply planning