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The energy absorption characteristics of composites are developed for applications likely to be subjected to sudden or prolonged impacts. In lightweight applications, the possibilities of Al 6061 composites are being explored with various known materials with similar properties. Three materials of low densities but high strength was combined: hexagonal honeycomb Al 6061 core was sandwiched with polyurethane foam and embedded within two glass fiber-reinforced polymer plates. L-9 orthogonal array Taguchi DOE was adopted for the design of the experiment varying the polyurethane mixture, core height, and face sheet thickness using the three-factor method. From the output of the Taguchi DOE, twenty-seven samples were fabricated. In order to determine the force-displacement relationship for each of the test samples, a three-point bending test was performed on a universal testing machine. Energy absorption (EA) and crushing force (CF) were determined from the force and displacement values. These values were then optimized to minimize the PCF while maximizing EA. Numerical analysis performed correlated with the results from experimental samples after testing. Since energy absorption is a measure of applied force and the resulting displacement on a material, the energy absorption characteristics were discussed. [ABSTRACT FROM AUTHOR]

A coupled Mori-Tanaka/finite element strategy was implemented to capture deformation profiles of aluminum AA 6063 cylindrical and hexagonal tubes reinforced with 60% variable coir-fiber thickness (5 mm, 10 mm) coir-fiber under variable oblique crushing. By a representative volume element (RVE) defined elastic moduli of the reinforcement phase hybrid tubes were simulated for the effect of reinforcement layer thickness under the Johnson-Cook's and Hashin's intralaminar damage with cohesive zone modeling. As, transformations in deformation underscored variabilities in shape, multicellularity and reinforcement thickness, a correlation is found between loading angles and peak crushing forces in evolving a lightweight absorber consistent with extreme oblique impacts. [ABSTRACT FROM AUTHOR]

SS 316L, a low-carbon 316 Stainless Steel, has been used to manufacture swivel mechanisms for paraplegic patients, but its weight is relatively high compared to a few materials in its range of properties. Aluminum alloy 6061 and Titanium alloy (Ti6Al4V) offer lightweight and incredible strength-to-weight ratio, hence their use for medical, aerospace, and automotive applications. This study, therefore, seeks a replacement for SS 316L. A 3D model of a swivel mechanism was developed to compare the performance of the swivel mechanism made with SS 316L, AA 6061, and Ti6Al4V. The kinematic analysis of the mechanism based on a range of weights: 1kN, 1.1 kN, 1.2 kN, 1.3 kN, 1.4 kN, and 1.5 kN was carried out to generate the inputs for the simulation. The 3D model was made with SolidWorks, and the results of the kinematic analysis were used to define the simulation parameters for the mechanism. Two scenarios generated depicted the full collapse of the mechanism and the full extension. The results showed that AA 6061 and Ti6Al4V outperformed SS 316L with higher yield strength and factor of safety. Therefore, swivel plates made with AA 6061 and Ti6Al4V have higher yield strength than those made with SS 316L, adding to the advantage that they have a higher strength-to-weight ratio. From this analysis and known knowledge of the cost of these materials, the optimal replacement considering cost with yield strength is AA 6061. However, Ti6Al4V is a better alternative for the strength-to-weight ratio for SS 316L. [ABSTRACT FROM AUTHOR]

This article is a book review of "Contemporary issues in Christian marriage: In commemoration of the retirement of Rev. Dr. Samuel Oluwafemi Oladimeji from active ministry of the Nigerian Baptist Convention." The book is a collection of essays on various topics related to marriage, written by different contributors. Each chapter addresses a different aspect of marriage, such as discerning God's will in selecting a partner, making the best of the dating period, and communication in the Christian home. The book also includes a short biography of Rev. Dr. Samuel Oluwafemi Oladimeji. While the book covers many important topics, the reviewer notes that some contemporary issues, such as divorce and artificial intelligence's role in marriage, are not addressed in the book. [Extracted from the article]

Sweet potatoes are extremely adaptable to adverse environmental conditions and can increase food security in times of drought and famine. However, in recent times sweet potato production has been on the decline due to pest and disease infestation. The objectives of the study were to describe the socio-economic characteristics of the sweet potato farmers; identify the common field/storage pest and disease of sweet potato; investigate the indigenous measures of controlling field/storage pests and diseases among others. One hundred and twenty-two sweet potato farmers were randomly selected from two local government areas. The study shows that majority of the sweet potato farmers were male (89.3%) and married (80.4%). The major field and storage pests were armyworm (100%), grasshopper (100%), and rat (100%). Black rot (x=2.39), and bacterial wilt (x=2.35) were the major field and storage diseases of sweet potato. The major challenges faced by sweet potato farmers with use of indigenous methods were proximity to natural herbs (100%). The study concluded that the use of indigenous measures to control sweet potato pest and diseases are very effective and beneficial. Therefore, the study recommended that Extension agent should work with the farmers on how the natural herbs can be preserved within their environment. [ABSTRACT FROM AUTHOR]

The spectrum of post-operative infections in neurosurgical practice includes scalp infection, bone flap osteomyelitis, meningitis and intracranial abscesses and is associated with significant morbidity and mortality. There is a wide variation across neurosurgical centres in the use of perioperative antibiotic prophylaxis. The aim of this study was to determine whether intraoperative wound irrigation with ceftriaxone provides additional prevention of surgical site infection (SSI) in patients already receiving the drug parenterally. This was a prospective randomized clinical study of patients 18 years and above scheduled for clean neurosurgical procedures and assigned to either study or control group using table of random numbers. Both groups had parenteral ceftriaxone at the induction of anaesthesia and for 24-h post-operation. In the study group, there was intra-operative wound irrigation with a ceftriaxone-in-normal saline solution while the wound in the control group was irrigated with only normal saline. Clinical and or laboratory evidence of SSI was used as the outcome measure. One hundred and thirty-two patients aged 18 years and above were recruited for this study. There were 66 patients in each group. The overall frequency of SSI was 2.27% (3 out of 132). The frequency in the ceftriaxone group was 3% (2 out of 66) while that in the control group was 1.5% (1 out of 66). These values were not significantly different (p = 1.00). There were four cases of wound edge necrosis, three of which developed SSIs. In this study, intraoperative antibiotic irrigation did not confer additional benefit in the prevention of SSI in clean neurosurgical procedures in which prophylactic intravenous antibiotics were administered to the patient. Wound edge necrosis was the most significant but preventable risk factor for the development of SSI in the setting of this work. [ABSTRACT FROM AUTHOR]

Vortex induced vibration (VIV) is the major cause of several catastrophic disasters due to fatigue failures induced by drag and lift forces in aerodynamic systems. This study investigates the control of VIV phenomenon through passive bubble tab(s) having a small diameter (d) relative to the main circular cylinder (D) in a two-dimensional (2-D) flow domain. Using ANSYS Fluent computational software, flow analysis was conducted at a Reynolds number (Re) of 80 for various bubble tab configurations at different spacing ratios (x/D) and diameter ratios (d/D). The drag coefficient, the velocity and pressure contours, along with the flow streamlines in each case were studied. The results indicated the optimized tab(s) positions for different spacing ratios, diameter ratios, and configurations. The study effectively established that passive bubble tabs can potentially control VIV associated with flows around a circular cylinder. [ABSTRACT FROM AUTHOR]