Thermodynamics Characterization of Density models for an Effective Solar Water Heater Sizing

The problem faced in Sizing of an effective Solar Water Heater (SWH) by engineers to meet certain design requirement is highly enormous. Using the thermodynamic characterization relation and the knowledge of Solar Water Heater (SWH) density’s model; various design were evaluated. The result shows that density model actually predicts adequately and providing alternative means of estimating these design parameters. Also, the properties of the system, such as entropy and enthalpy (specific heat capacities), which cannot be determined directly from experimental axiom, were evaluated. These evaluations therefore, give room to express the thermodynamics properties of the system and consequently improve the design performance. Further comparisons with experimental results reveal a better outfit. Therefore through the knowledge of thermodynamic relation an efficient Solar Water Heater is operated and empirical data is expanded

Effects of Pouring Temperature on Solidification Using Energy Profile Analysis on Aluminum Alloy

This work covered the study of energy profiles as influenced by solidification on sand cast 6063 aluminum alloy. Temperature is an important parameter, most especially in foundry technology that influences properties and morphology of cast products. Different pouring temperatures of 680oC, 740oC and 780oC were considered. Mechanical energy expended and the quantity of heat evolved was evaluated from results obtained from tensile test experiments carried on the three samples. Relationship between change in coefficient of thermal expansion and change in applied tensile load were derived; it was observed that the maximum energy expended before fracture for samples decreased with increasing pouring temperature. Increasing pouring temperature decreased the amount of energy to be expended during deformation. This also influenced the change in heat evolved per time

Physio-Chemical and Mechanical Behaviour of(Pinussylvestris) as Binders on Foundry Core Strength

The mechanical potential of sand core binders made withPinussylvestris has been examined. Ota silica base sand bonded with 6% of cassava starch in admixed proportion of Pinussylvestris was tested for tensile, compressive strength and permeability to establish the binding efficiency. Tensile strength of the green baked core were oven baked at 50°C, 100°C, 150°C and 200°C.The cylindrically shaped permeability specimens were tested with permeability meter. Study revealed thatPinussylvestris showed an improve properties at 6% cassava starch at 200°C

Dynamic Crystallization: An Influence on Degree of Prior Deformation and Mechanical Strength of 6063 Aluminum Alloy

This research is aimed at investigating the influence dynamic solidification of melts on degree of mechanical deformation and mechanical strength of 6063 aluminum alloy. Cylindrical samples of 14mm diameter and 140mm long were die cast following two techniques – vibration and static. Prior deformation via forging was imposed on each solidified sample to achieve 7%, 14%, 21% and 28% thickness reductions respectively for each casting technique. Average deformation load, average hammer velocities and the average energy absorbed were recorded. Tensile properties of each sample were studied via the use of Monsanto tensometer. Mechanical agitation of mould and its content increased the machinability of the alloy even at higer pre deformation. This was justified by the failure of the 28% reduction sample cast on static floor during machining to a tensile piece. The energy absorbed during deformation influences the tensile strength of the material. This increases with increase in percentage deformation except for 28% reduction whose magnitude was lower than that subjected to 21% reduction; vibrated samples possessed superior properties. From results obtained, vibrating a sample and subjecting to 21% pre-deformation possessed the best tensile strength

The influence of steel die parameter and micro-structural investigation on AA6063 aluminum alloy

The study investigated the influence of steel die parameter and the microstructural evaluation of AA 6063 aluminum alloy extruded at room temperature using different die entry angles. Mild and tool steel dies of entry angles of 15o, 30o, 45o, 60o, 75o and 90o were used to extrude the work sample. Microstructural analysis, coupled with ram velocity, elongation, hardness, and maximum extrusion pressure of the extruded samples, were de-termined. It was observed that theaximum extrusion pressure required for extrusion and hardness of extruded samples increased with increasing die entry angle .Experimental results show that aluminum alloy deforms better when the die material is made of mild steel with die entry angles of 45o, 75o and 90o as compared to tool stee

INFLUENCE OF INOCULANT ADDITION AND COOLING MEDIUM ON THE MECHANICAL PROPERTIES OF AA 6063-TYPE Al-Mg-Si ALLOY

Studies have been made on the influence of water and air cooling coupled with inoculation on the mechanical properties of 6063 aluminum alloy. The work was aimed at investigating the combined effects of two crystallization enhancers in order to provide a synergy-form of effect in the mechanical properties using 4.2% wt and 16.5% wt Ni powder particles. The alloying compositions, phase change and micro-hardness were determined by using energy dispersive spectroscopy (EDX), XRD and Brinell microhardness tester. The surface morphology of the alloyed sample using scanning electron microscopy (SEM) showed that Ni particles were distributed by virtue of surfactant addition and mechanical stirring. Addition of Ni powder coupled with increase in solidification rate yield size reduction in aluminum alloy structure. The results also revealed that conglomeration of inoculant addition and water cooling increased the fracture strength of the aluminum alloy while both axial and lateral deformations were altered

MATERIAL PERFORMANCE INVESTIGATION ON THE FAILURE OF AN AIRCRAFT (ABT-18) NOSE WHEEL STRUT

The study investigated the cause and mechanism of failure of the nose wheel strut of a trainer aircraft with respect to material selection.Various methods and tests ranging from visual examination via unaided eye and fractography, hardness tests, chemical analysis and microstructural examination were employed for the study. The results show chevrons on the fracture surface which indicates fatigue failure characteristic of brittle fracture. Also, thefractographshowsincidence of a ductile pull and high energy fracture.This is evident by the cone shape of the fractograph and the observed tear.Hardness tests results showed high discrepancy between the values of the failed and undamaged samples indicating loss of strength and ductility in the failed sample as a result of fatigue. The outcomeof chemical analysis revealed that the component is made from medium carbon steel of the tough grade instead of the required spring steel.Therefore, a major cause of the failurecan be linked to improper material specification for the nose wheel strut.The failure mechanism was further confirmed by microstructural examination which revealed fatigue cracks propagated from inclusions in the microstructure of the failed sampl

Structural Modification, Strengthening Mechanism and Electrochemical Assessment of the Enhanced Conditioned AA6063-type Al-Mg-Si Alloy

Enhancement of engineering materials is essential for averting service failure and corrosion attack in the industries. The impact of Ni as inoculant and solidification process on the corrosion resistance of an Al-Mg-Si alloy has been investigated in 3.65% NaCl solution using potentiodynamic polarization measurement. The alloying compositions and phase change were determined with energy dispersive spectroscopy (EDX) and x-ray diffraction (XRD). The surface morphology of the alloyed sample using scanning electron microscope (SEM) showed that Ni particles were well dispatched along the interface. The addition of Ni to Al-Mg-Si alloy led to the precipitation and crystallization of Al2Ni and AlNi2 formed at the grain boundaries. Equally, as the percentage of Ni content increases in the alloy, the corrosion rate decreased due to the presence of Al2Ni3 which proceeded at active regions. Inoculation of Ni particles coupled with increase in solidification reduces the possibility of corrosion penetration within the structural interfac

Extrusion die geometry effects on the energy absorbing properties and deformation response of 6063-type Al-Mg-Si alu1ninum alloy*

The response of 6063-type AI-Mg-Si alloy to deformation via extrusion was studied using tool steel dies with 15°,30°,45°,60° and 75o entry angles. Compressive loads were subjected to each sample using the AVERY DENISON machine, adapted to supply a compressive load on the punch. The ability of the extrudate to absorb energy before fracture was calculated by integrating numerically the polynomial relationship between the compressive stress and sarnple strains. Strain rate was calculated for each specimen and the deformation zone length w~s mathematically derived from the die geometry to decipher its influence on both lateral and axial deformations. Results shcv-1Ed that cxtntr:ling with a 15° die was the fastest as a result of the low flow ;.iress encountered. Outstanding compressive strer:gth. plastic deformation, strain rate and e:1e1gy absorl'inz ca1~acity were observed for the alloy extruded with a 75" di~> angle. Increase in die ;mgles led to a decreJ~;e in cleformJtion zone length and samples deformed more in the axial direction than in the lateral e>.cep~ for the 45° die which showed the opposite; the sample also showed the least ductility

Biomaterials for Drug Delivery: Sources, Classification, Synthesis, Processing, and Applications

A way to avoid or minimize the side effect that could result in drug delivery to cells with increased efficiency and performance in the health rehabilitation process is to use biocompatible and biodegradable drug carriers. These are essentially biomaterials that are metallic, ceramic, or polymeric in nature. The sources of these materials must be biological in its entire ramification. The classification, synthesis, processing, and the applications to which these materials are put are the essential components of having suitable target cell drug carriers. This chapter will be devoted to discussing biomaterials suitable as drug carrier for use in the health-related matters of rehabilitation