NUMERICAL SIMULATION OF OUTER DIE ANGLE OF EQUAL CHANNEL ANGULAR EXTRUSION PROCESS

The study of the simulation of effect of outer die angle in Equal Channel Angular Extrusion (ECAE) process was investigated. The simulation was carried out on 6063 aluminium alloy with a view to achieve ultra-fine grain structures. ADINA user interphase Version 8.6 (900 modes) was used for the simulation. The unextruded parameters of the 6063 aluminium alloy were used as input codes and some basic assumptions were made in designing the model on 2-Dimensional scale. The billet was meshed by dividing the vertical and horizontal geometry into 30 and 4 elements respectively. The die angle was varied from 0o to 90o and the simulation results were displayed. The results showed that the force of 27.5X106 N, 27.5X106 N, 27.6X106 N and 31.2 X106 N was required to deform when the outer die angle was 0o , 22.5o , 45o and 90o respectively. Also, the strains achieved were 0.61, 0.62, 0.66 and 0.69 respectively. Thus, highest force is required at 90o and the strain achieved at 0o is the lowest. Based on the results, it was recommended that it is more economical to extrude at an outer angle between 22.5o and 45o as a relatively higher effective strain will be induced

Equal Channel Angular Extrusion Characteristics on Mechanical Behavior of Aluminum Alloy

Materials strengthened by conventional methods such as strain hardening, solute additions, precipitation and grain size refinement are often adopted in industrial processes. But there is limitation to the amount of deformation that these conventional methods can impact to a material. This study focused on the review of major mechanical properties of aluminum alloys in the presence of an ultrafine grain size into polycrystalline materials by subjecting the metal to an intense plastic straining through simple shear without any corresponding change in the cross-sectional dimensions of the sample. The effect of the heavy strain rate on the microstructure of aluminum alloys was in refinement of the coarse grains into ultrafine grain size by introducing a high density of dislocations and subsequently re-arranging the dislocations to form an array of grain boundaries. Hence, this investigation is aimed at gathering contributions on the influence of equal channel angular extrusion toward improving the mechanical properties of the aluminum alloys through intense plastic strain

Security Risks Management in Selected Academic Libraries in Osun State, Nigeria

The survival of a library depends to a large extent on how secured its collections are. Security of collections constitutes a critical challenge facing academic libraries in Nigeria. It is against this background that this studyinvestigated the security risks management in selected academic libraries in Osun State, Nigeria. The study adopted a descriptive survey design of the ex-post facto type. The population of the study comprised 145 librarypersonnel and 14,317 registered library users in four selected academic libraries in Osun State while the sample size consisted of all the145 library personnel and 2% of the registered users to make a total of 432  respondents. Questionnaire and interview with the Chief Librarians of the selected academic libraries were the instruments used for data collection. Data were analysed using frequency distribution and percentages run using statistical package for social sciences (SPSS). The study established that the most prevalent security risks in the libraries included stealing/theft of library materials, mutilation of library materials, defacing,   misuse/mishandling of library materials, insect attack, fire outbreak and flood. It also established inadequate funding, shortage of staff/personnel, erratic power supply and lack of institutional security policy/disaster plan as some of the challenges confronting security management in the libraries. Based on the findings, recommendations were made towards improving security management in the libraries

NUMERICAL SIMULATION OF OUTER DIE ANGLE OF EQUAL CHANNEL ANGULAR EXTRUSION PROCESS

The study of the simulation of effect of outer die angle in Equal Channel Angular Extrusion (ECAE) process was investigated. The simulation was carried out on 6063 aluminium alloy with a view to achieve ultra-fine grain structures. ADINA user interphase Version 8.6 (900 modes) was used for the simulation. The unextruded parameters of the 6063 aluminium alloy were used as input codes and some basic assumptions were made in designing the model on 2-Dimensional scale. The billet was meshed by dividing the vertical and horizontal geometry into 30 and 4 elements respectively. The die angle was varied from 0o to 90o and the simulation results were displayed. The results showed that the force of 27.5X106 N, 27.5X106 N, 27.6X106 N and 31.2 X106 N was required to deform when the outer die angle was 0o, 22.5o, 45o and 90o respectively. Also, the strains achieved were 0.61, 0.62, 0.66 and 0.69 respectively. Thus, highest force is required at 90o and the strain achieved at 0o is the lowest. Based on the results, it was recommended that it is more economical to extrude at an outer angle between 22.5o and 45o as a relatively higher effective strain will be induced

Microstructural Characterization and Some Mechanical Behaviour of Low Manganese Austempered Ferritic Ductile Iron

This work studied the microstructural characterization and mechanical behavior of low manganese Austempered Ductile Iron (ADI), with a view to improve the properties of iron and to increase the areas of applications. Three sets of ductile iron of specified composition were machined from Y-blocks to tensile and hardness pieces. The samples were preheated at 350 0C for 1hr and austenitised at 900 0C for 1hr in salt bath furnace. The three sets of samples were immediately austempered in the austempering salt bath furnace at uniform austempering temperatures of 300 0C, 350 0C and 400 0C for 90, 120 and 150 minutes; each sample for each temperature window. All sets were prepared for metallographic examination; tensile and hardness tests were carried out. The results showed that maximum hardness, tensile and yield strength were obtained at austempering temperature of 350 0C and at 150 minutes. At 300 0C and 350 0C, it was noticed that the hardness and strength increase with austempering time. The optimum tensile strength was 1300 MPa at 350 0C after austempering for 150 minutes. In conclusion the austempering operation has a significant effect on the mechanical and microstructural properties of ADI

MECHANICAL AND MICROSTRUCTURAL CHARACTERIZATION OF DUCTILE IRON PRODUCED FROM FUEL - FIRED ROTARY FURNACE

The work compared the mechanical and microstructural properties of ductile iron produced in a locally manufactured fuel- fired rotary furnace with ASTM A 536 65-45-12, with a view to standardizing the produced ductile iron. Sets of low alloyed ductile iron were produced in form of keel Y-block inside green sand mould, using a rotary furnace of 100 kg capacity. The base alloy was treated with 5.5 wt. % Mg-Fe-Si alloy for spheroidisation followed by post inoculation with 75 wt. % Fe-Si. The samples of the as-cast were machined to mechanical test samples of tensile, yield and hardness. The microstructural and mechanical characterizations of the samples were carried out using computerized Instron Electromechanical Testing Machine (Model 3369), Mansato Tensometer (Model W) and Nikon Eclipse metallurgical microscope, Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) method. The results showed that the yield and tensile strength of the produced ductile iron were 367 and 540 MPa respectively with the hardness value of 185 BHN. The results obtained were compared with standard ASTM A 536 65-45-12 to confirm the suitability of the manufactured fuel-fired rotary furnace for the production of ductile iron

Study of the Performances of Nano-Case Treatment Cutting Tools on Carbon Steel Work Material during Turning Operation

The degree of holding temperature and time play a major role in nano-case treatment of cutting tools which immensely contributed to its performance during machining operation. The objective of this research work is to carryout comparative study of performance of nano-case treatment tools developed using low and medium carbon steel as work piece. Turning operation was carried out under two different categories with specific work piece on universal lathe machine using HSS cutting tools 100 mm x 12mm x 12mm that has been nano-case treated under varying conditions of temperatures and timeof 800,850, 900, 950oC and 60, 90, 120 mins respectively. The turning parameters used in evaluating this experiment were cutting speed of 270, 380 and 560mm/min, feed rate of 0.15, 0.20 and 0.25 mm/min, depth of cut of 2mm, work piece diameter of 25mm and rake angle of 7o each at three levels. The results of comparative study of their performances revealed that the timespent in the machining of low carbon steel material at a minimum temperature and time of800°C, 60 mins were1.50, 2.17 mins while at maximum temperature and time of 950°C , 120 mins were 1.19, 2.02 mins. It was also observed that at a corresponding constant speed of 270,380 and 560mm/min at higher temperature and time, a relative increased in the length of cut were observed. Critical observation of the result showed that at higher case hardening temperature and time (950°C/120mins), the HSS cutting tool gave a better performance as lesser time was consumed during the turning operation

The Prevalence, Effects, and Reactions to Use of Short Message Services in University Settings in South West Nigeria

This chapter focuses on the extent of the usage of Short Message Services (SMS) in three universities in Southwest Nigeria, with 243 participants drawn from Covenant University, Bells University, and Lagos State University, who responded to a questionnaire on SMS. Data generated from the study confirmed the high usage of SMS among subjects in general and males in particular, within the age range of 31 to 40 years; a large number of subjects, especially those in administrative positions, were affected by the usage of SMS; most of the subjects are more tolerant when the messages are related to religion, are work-related, or are from family members. Subjects expressed concern when the contents of the SMS are related to adverts, when SMS are used when there are network problems, and the possible exploitation of recipients. Steps to minimize the disadvantages of the use of SMS are discusse

CONTRIBUTORY ROLE OF INSTITUTIONAL, LEGAL AND ETHICAL FACTORS AS PRECURSORS OF CONSORTIUM BUILDING READINESS AMONG UNIVERSITY LIBRARIES IN SOUTHWESTERN NIGERIA

Consortium Building Readiness (CBR) is inevitable for university libraries that intend to provide adequate information resources and services to users. Preliminary investigations showed that efforts at CBR have not been successful in Nigeria. This may be as a result of the unpreparedness among university libraries to provide Institutional Factors–IF (Organisational Culture–OC, Organisational Policy–OP, finance, Power Supply–PS, Internet Connection–IC, ICT Literacy skills–ILS and digitisation), Legal Factors–LF (Governing Law–GL, Log-in-Option–LO, Non-disclosure of Log-in-Option–NDO, Dispute Resolution–DR, Cash Contribution–CC and dissolution) and Ethical Factors–EF (professional and business) to drive Consortium Building (CB). Little attention, however, has been paid to factors that could predict readiness for a successful CB among university libraries. This study therefore was carried out to investigate institutional, legal and ethical factors as precursors of CBR among university libraries in Southwestern Nigeria. Exchange and Resources Dependence, Social Exchange, Socio-Technical theories and Teamwork Model were used as the framework, while the survey design of the correlational type was adopted. All the 643 university library personnel in 45 university libraries in southwestern Nigeria were enumerated. The instruments used were Institutional Factors (α=0.75), Legal Factors (α=0.79), Ethical Factors (α=0.89), CBR (α=0.81) scales. Key informant interviews were conducted with nine selected university librarians. Quantitative data was analysed using descriptive statistics, Pearson product moment correlation and Multiple regression at 0.05 level of significance, while the qualitative data was thematically analysed. The IF, LF and EF jointly influenced CBR (R = 0.47; F(3; 545) =51.17; Adj. R2=0.22), contributing 22.0% of its variance. The business ethics (β=0.34), OC (β=0.33), GL (β=0.24), LO (β=0.24), finance (β=0.17), PS (β=0.10) and digitisation (β=0.07) relatively contributed to CBR. The university librarians complained that CBR was impossible due to lack of acceptable platform for all university libraries to disseminate and share resources. There were yearnings to come together as a team of consortium but finance and organisational commitment of their various institutions limited the move. Business ethics, organisational culture, governing law, log-in-option, finance, power supply and digitization and accessible platform level enhanced consortium building readiness among university libraries in southwestern Nigeria. These factors should be addressed to drive consortium building among them

Mechanical Behaviour and Microstructural Characterization of Carbon Steel Samples from Three Selected Steel Rolling Plants

The research investigated the mechanical behavior of samples of steel rods obtained from three selected Steel Rolling Companies in South Western part of Nigeria. This was done by carrying out some mechanical tests such as tensile, impact and hardness as well as microstructural examination.Four sets of 16 mm steel rod samples were collected from Tiger steel industries, Phoenix steel and Oxil steel Industies, all located in South West Nigeria, The chemical composition was carried out using a Spectrometer (EDX3600B). Afterwards, different samples were prepared, cut and machined according to ASTM standards dimensions of tensile and impact tests as well as hardness test from which their Ultimate tensile Strength, Yield strength, Percentage elongation, Impact strength and Brinell hardness number were obtained and compared to three standards (ASTM A706, BS 4449 and Nst 65-Mn). Their microstructures were also examined and analyzed.The results showed that the Ultimate tensile strength for the samples from Oxil steel, Phoenix Steel and Tiger steel were 661 N/(mm)2, 653 N/(mm)2 and 631 N/(mm)2 respectively while their hardness values were 150 BHN, 178 BHN, 214 BHN respectively. The sample from Tiger steel and Oxil Steel had the finest and most coarse microstructure respectively. In conclusion, it was observed that the results of the sample analysis from the three selected Steel Rolling Companies conformed to most of the standards except the sample from Tiger steel which had a high hardness value compared to the standard