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A Comparative Analysis of Grillage Method and Beam line Analysis of a Reinforced Concrete Waffle Brifge Deck
(Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2022-01-23) Adamu, H. N.; Abbas, B. A.; Abubakar, M.; Yusuf, A.; Kolo, D. N.; Shehu, M.
The analysis of reinforced concrete waffle bridge deck using Chanchaga bridge as a case study was carried out with the aid of computer program written in MATLAB. The bridge deck which is a beam bridge was idealized to be a waffle slab. A mathematical model of the bridge was developed using the method of grillages because very complex shapes of problem domain with prescribed conditions can be handled easily using the method. The bridge deck was modelled as interconnection of grid elements. The analysis was carried out using direct stiffness matrix method. The nodal displacements and the resulting static internal forces; shear forces, bending moments and twisting moments of each grid element were determined using the matrix. The results obtained using the method of grillages were then compared with beam line analysis and the former method gave a 10% decrease in forces which will result in the reduction of overall design and materials by 10%.
A Comparative Evaluation of the Networks of Three Nigerian Federal Universities for Effective Library Services
(Ghana Library Journal, Ghana, 2013) Abduldayan, F.J.; Oluwade, B.; Oyedum, G.U.
This paper is a comparative evaluation of the networks of three Nigerian federal universities and how such networks can be used to enhance library services. The university networks included in this study are the Federal University of Technology Minna Network (FUTMINNet), University of Jos Network (UNIJOSNet) and University of Lagos Network (UNILAGNet). University of Minna (FUTMIN), established in the 1980s, belongs to the third generation of Nigerian universities; University of Jos (UNIJOS) (established in the 1970s) belongs to the second generation, while University of Lagos (UNILAG) (which was established in the 1960s) belongs to the first generation. Both FUTMIN and UNIJOS are located in North Central geo-political zone of Nigeria while UNILAG is located in the South West zone. The research design employed was the survey method (involving the use of questionnaire, interview, and direct observation) to study the wired and wireless connectivity of the networks of the three universities and compare them against criteria such as network speed, bandwidth, latency, and user response. Structured and semi-structured questionnaires were administered to the network users of each of the three universities, giving a total of 300 questionnaires for the study. The result of the study shows that UNIJOSNet is the fastest while in terms of the wired service, UNILAGNet is the fastest. FUTMINNet is not performing well compared with the UNIJOSNet and UNILAGNet, or not satisfying its users at a satisfactory level. Wireless services of UNIJOSNet and UNILAGNet, which in turn affects the quality of library services offered to users. Wireless services of FUTMINNet do not adequately meet the expectations of users of library services. The paper recommends that the library network services of UNILAGNet has the best performance, while FUTMINNet needs the most improvement. Finally, universities need to enhance their wireless networks by upgrading and expanding the network components and infrastructures of all the networks, especially FUTMINNet.
ACCESS TO COMMUNICATION BASED TECHNOLOGY AS A PANACEA FOR KNOWLEDGE MANAGEMENT AMONG FACULTY OFFICERS IN AHMADU BELLO UNIVERSITY, ZARIA, KADUNA STATE, NIGERIA
(Pakistan Librarians Welfare Organization (PLWO), 2022-09-15) Suleiman, Hussaini; Goshie, Rhoda Wusa; Jaafar, Sani; Jimada, Aisha
This article was undertaken to investigate Access to Communication based Technology as a Panacea for Knowledge Management among Faculty Officers in Ahmadu Bello University, Zaria, Kaduna State, Nigeria. The study was guided by two research questions and objectives. The research methodology was purely quantitative and a descriptive research design was used. The study population includes 108 Faculty Officers in the five Ahmadu Bello University Teaching Hospital Schools, Shika Zaria. Yamani's formula was used to determine the target population sample of 91 respondents. A questionnaire was used to collect data. A simple random sampling method was used as the sampling method to collect data from the study area. The tool was subjected to face and content validity. The pilot study was conducted at Ahmadu Bello University, Zaria’s main campus, which was outside the key study areas but with similar characteristics, and was also tested for reliability using a split- half test, and obtained a reliability coefficient of 0.81. Data were analyzed using descriptive statistics and Statistical Package for Social Science version 21.0. Among other things, the results of the study showed that the greater part of respondents indicated that email, online relay chats, Internet telephony, instant messaging, web services, and video conferencing were the types of Internet facilities or services required and accessible for Ahmadu Bello University Faculty Officers Shika Zaria Most respondents indicated that some of the factors that discourage the use of Internet facilities by Faculty Officers are lack of Internet access and inappropriate research on Internet skills. It recommended, among other things, that the management of Ahmadu Bello University Hospital, Shika, Zaria, should make more computer systems available to the Faculty Officers in the various schools of the institution to allow them unproblematic access to the Internet facilities.
ACQUISITION OF ONLINE COMPETENCIES OF LIBRARIANS THROUGH THECONTINUOUS STAFF DEVELOPMENT PROGRAMS FOR IMPROVED JOB PERFORMANCE IN ACADEMIC LIBRARIES IN NIGERIA: A REVIEW OF CONCEPTS AND CHALLENGES
(Library Department University of Nigeria, Nsukka, 2022-04) Goshie, Rhoda Wusa; Muthee, Daniel; Mutwiri, Caroline
Purpose: The purpose of this paper is to review the acquisition of online competencies of Librarians through the Continuous Staff Development Programs for Job Performance in AcademicLibraries in Nigeria. Academic libraries have provided, served and executed their obligations of collection development, user education, reference services, and current awareness services traditionally to their users by employing tangible resources to deliver information services. Due to the huge increase of knowledge, the emergence of modern technology and the changes in trends in libraries services, libraries are needed to accomplish more, and the competencies library professionals require continue to change. Libraries throughout the world are grappling with the present issues of technological development, globalization, and digitalization of information. librarians must be familiar with the following competencies in an online environment: e-reserves bibliographic instruction software, management systems, apple and Microsoft systems, instructional design products, a wide range of classroom software applications, serials management software and library integrated systems Design/Methodology/Approach: The paper adopted conceptual approach. It defines the concept of Continuous Staff Development Programs, types of Continuous Staff Development Programs, acquisition of online competencies skills, The use of ICT in the acquisition of online competencies, competencies needed by librarians, challenges of Continuous Staff Development Programs on job performance, conclusion and recommendations. Implication: The paper contends that although the library profession has proliferation of program there still there exists low improvement in the acquisition of online competencies for job performance.Almost all experts now believe that continual learning is necessary for library/information personnel to provide effective service. It is also essential since it will allow librarians to reap the full advantages of these programs and apply their newly gained skills on the job. Librarians must grasp the online competencies in order to execute their duties successfully and efficiently. Originality/ Value: It is therefore imperative that the university librarians function effectively in their services in order to fulfill the demands of the clientele. CPD is a lifetime learning process that allows one to broaden one's profession and competency helps to satisfy the current and future of patrons needs which offers better service outcomes and priorities. It ensures that a person has necessary levels of knowledge and competencies that helps in increasing professional area of practice
AGRICULTURAL INFORMATION SERVICES PROVISION BY LIBRARY STAFF OF COLLEGE OF AGRICULTURE LIBRARIES IN NIGER STATE, NIGERIA
(Publication of the Depaprtment of Library and Information Science, University of Nigeria Nsukka, 2020-04-04) Adamu, Mohammed Saba (CLN, MNLA, CTN), Kasim, Muhammad Bala (CLN), Adamu, Mahmud (CLN)and Abubakar, Fati (CLN)
This study investigated the agricultural information services provision by library staff of college of agriculture libraries in Niger State, Nigeria. The research design adopted for this study was descriptive survey research design. The population covers the staff of the libraries. The instruments used for data collection were checklist containing items on availability of agricultural information services and questionnaire containing items on methods of providing of agricultural information services and strategies to enhance provision of agricultural information services and strategies for enhancing the provision of agricultural information services. Data collected were analysed using frequency counts and percentages. Findings showed that outreach services, bibliographic services, user education, reprographic services, current awareness services (CAS), etc were not provided; ICTs based information provision models such as Web portal, Voice-Based service, Text (SMS) Based service, Self-support online community service, Interactive video conferencing service etc were not in use in the College of Agriculture Libraries in Niger State. The study recommended provision of outreach services, bibliographic services, user education, reprographic services, current awareness services (CAS), etc and make use of latest technologies such as ICTs based information provision models, Smart Phones, CD-ROM, Radio, Television, Computer show case etc to provide agricultural information services to their clienteles
An Investigation of Partial Shading Effects on Solar Photovoltaic Module Performance Using Infrared Thermography
(4th International Engineering Conference (IEC 2022) Federal University of Technology, Minna, Nigeria, 2023-03-21) Jaji, .U. F.; Bori Ige
Partial shading is detrimental to the performance of a solar PV module. This is because it not only reduces the current and voltage of the module which leads to power loss in the module but may also lead to the formation of hotspots. This work presents an investigation carried out on the cross-comparison of two different PV modules subjected to the same ambient conditions in a tropical hot climatic region, to observe the effects of partial shading on them and if hotspots are formed, determine if they are heightened by the climatic condition of the environment. Different shading patterns and shading due to partial obstruction of direct radiation were considered. Shading was achieved using opaque shading sheets. The results of the experiment showed that the efficiency or performance of these modules is dependent on the type and direction of shading. This implies that as the percentage of shading increases, there is a decrease in power output and ultimately its efficiency. Also, thermal images obtained showed that asides temperature difference between the modules, hotspots formed on the test modules were not magnified by climatic conditions. The Infrared image indicated the likelihood of an internal defect in the control module. Considering the emergence of new solar technologies to improve its efficiency, it’s recommended that a similar investigation under real outdoor conditions be carried out on Perovskite solar cells. Results of the outcome of the findings should be compared to those of the silicon crystalline modules, to determine which solar technologies perform better.
An Investigation On Ventilation and Air Conditioning (VAC) Installation, Design and Performances of Selected Buildings in Ilorin, Kwara State, Nigeria
(2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria, 2017-10-17) Yusuf, .A. W.; Bori Ige; Nasir, .A.
time. Heating, ventilation and air-conditioning (HVAC) play an important role in providing a comfortable condition for occupants in a building. This work concerns air conditioning designs, installations, and performances of some event centres namely: Banquet Hall, Atlantic Event Centre and Nimatoni Event Centre and some offices within the Kwara State Ministry of Water Resources. The impact of the effect of improper design and ventilation on energy efficiency and consumption were also considered. The event centres and offices were studied, by taking both the temperature and relative humidity values for over a period ranging from 75 minutes to 130 minutes, with the use of a device referred to as HOBOware temperature/relative humidity data logger coupled with a HOBOware Software interface installed on a personal computer, for post processing of acquired data. The obtained results of the event centres showed variations in the capacities of the installed air-condition understudied. Also from the results obtained, the cubic meter per minute (cmm) values were found to be 0.0896, 0.2908 and 0.0404 for Banquet hall, Atlantic Event Centre and Nimatoni Event Centre respectively, and these were below the standard recommended value of 0.4245 in the literature.
AN OPTIMIZED SINGLE-STEP BLOCK HYBRID NYSTRÖM-TYPE METHOD FOR SOLVING SECOND ORDER INITIAL VALUE PROBLEMS OF BRATU-TYPE
(African Journal of Mathematics and Statistics Studies, 2023-12-12) Joel Olusegun Ajinuhi; Umaru Mohammed; Abdullahi Idris Enagi; Onanmayi Razaq Jimoh
In this paper, a global single-step implicit block hybrid Nyström-type method (BHNTM) for solving nonlinear second-order initial-boundary value problems of Bratu-type is developed. The mathematical derivation of the proposed BHNTM is based on the interpolation and multistep collocation techniques with power series polynomials as the trial function. Unlike previous approaches, BHNTM is applied without linearization or restrictive assumptions. The basic properties of the proposed method, such as zero stability, consistency and convergence are analysed. The numerical results from three test problems demonstrate its superiority over existing methods which emphasize the effectiveness and reliability in numerical simulations. Furthermore, as the step size decreases as seen in the test problems, the error drastically reduces, indicating BHNTM's precision. These findings underscore BHNTM's significance in numerical methods for solving differential equations, offering a more precise and dependable approach for addressing complex problems.
Analysis of Solar Energy Potentials in Katsina and Sokoto States, Nigeria
(Nigerian Institution of Mechanical Engineers (NiMeCHE), 2020-10-20) Irekeola, .B. J.; Bori Ige; Adedipe, .O.; Babawuya, .A.
For many years, Nigeria has been facing energy crisis that is hampering her economic development. Energy is one of the key fundamentals for economic development and it is also fundamental to all human activities in this era. In this study, renewable energy potentials in Sokoto and Katsina states were analyzed respectively. Data covering a period of ten years (2007 - 2017) were obtained from the Nigerian Meteorological Agency (NIMET), Abuja, for monthly average daily solar radiation, maximum and minimum temperatures for the two states under investigations. The data were subjected to statistical analysis such as normality test, to examine whether the data is normally distributed using standardized coefficient of skewness, and kurtosis using a 250 Watts by 1.68m square solar panel; the results show that the solar radiations are negatively skewed by a value of -0.6 and -0.43, which makes the two states more reliable during the dry season of the year. The two states have a kurtosis of -1.17 and -1.38 indicating that the bell shape is slightly flatten than normal distribution shape. A linear regression model was also developed to predict the trends in solar radiation for the study area. The results show that Katsina state has a higher reliability (0.86) for solar energy potentials than Sokoto state (0.72).
Application of Inverse method to Reconstruct the form of Pulse During Impulsive damage to Pipelines
(International Engineering Conference (IEC), 2015) O. A. Olugboji; J. Hale; J. Y. Jiya; C. K. Jack
Petroleum pipelines damages if untimely detected, poses a tremendous challenge to the oil sector of an economy as it causes oil spillage, theft or explosion of the petroleum products while on transit. It is against this backlash an inverse pulse propagation method for reconstructing the form of pulse generated during pipeline defects was devised and presented in this paper. Inverse problem occurs in several branches of science and engineering. It involves the determination of the parameters of a model that describes or explains a set of observed data .This work deals with an inversion technique that was developed to reconstruct the form of a pulse after it has been propagated along a pipe. To test the suitability of the developed technique, a mathematical model was developed. The theoretical model was validated by experiment using a developed pipeline system. The experimental test rig comprises of a flexible hose pipe 23m long and 19mm diameter with four pressure sensors distributed along the pipeline and connected to the data acquisition system. Static and flowing air in the pipeline were use in the experimental test to validate the developed inverse technique model. The inverse method showed a close relationship to the original pulse.
Approaches to Security of Information Resources in Academic Libraries in Niger State, Nigeria
(Samaru Journal of Information Studies, 2018-04-16) Fati Abubakar & Dr. B. S. Aduku
This study examines approaches to security of information resources in academic libraries in Niger State. Three research objectives were framed for the study. The case study design was adopted for the study, and purposive sampling technique was used to select 35 respondents from a population of 297 staff in all the 12 academic libraries in Niger State. Semi structured interview guides were used to collect data from respondents, while field notes guide were used to record data in respect of participants’ observation. The data collected were subjected to qualitative analysis. The findings revealed that: the common approaches adopted for the security of information resources included periodic random checks on users and staff, scheduled patrols, and checking of users IDs, while computers of some libraries had antivirus software installed, and passwords configured. However, surveillance cameras were functional in only one library. The prevalent threats in all the libraries included book theft, mutilation of information resources, and non-return of borrowed library materials, impersonation, and computer virus attack. The 12 libraries had policies guiding the security of information resources, but they did not have insurance cover. It was concluded that although academic libraries in Niger State have adopted good approaches for securing their information resources. The fact that they paid more emphasis on printed materials, with less use of electronic security systems, it is obvious that the libraries were yet to embrace the opportunities offered by technological advancement for such activities. In view of the findings, it was recommended that libraries should endeavour to have written policies on all aspects of security of information resources, while efforts should be made to improve the qualities of such materials that have already been degraded or replace them if necessary. Finally, it would be necessary to enhance the manual methods of safeguarding library materials, while emphasis should gradually shift to the electronic methods.
Assessment of Customer Satisfaction with Products and Services of Academic Libraries in Zaria Metropolis
(Academic Library and Information Science, 2015-09) Denen, Nehemiah Kwaghgba; Matthew, Terfa Chorun; Goshie, Rhoda Wusa
This paper discusses customer satisfaction with products and services of academic libraries in Zaria metropolis. The products include books, internet access, journals, databases, newspapers and magazines and so on. The libraries comprise of Kashim Ibrahim Library of Ahmadu Bello University, Samaru, Federal college of Education, Nuhu Bamalli Polytechnic and Ameer Shehu College of Advance studies Libraries all in Zaria Metropolis. Survey method was adopted for the research. The population was 377 respondents. Questionnaires were used for data collection. Tables, frequencies and percentages were used to analyze the data. It was found out that customers of these libraries are satisfied with the products and services of the academic libraries in Zaria metropolis.
Assessment of Safety Provisions on Building Construction Sites in Abuja, Nigeria: Professionals and Workers Perspectives
(Proceedings of the 2nd International Engineering Conference, Federal University of Technology Minna, Nigeria., 2017-01-02) Kolo, D. N.; Yitmen, I.; Tsado, T. Y.; Abdullahi, M.; Yakubu, D. M.
Despite the growth of the building construction sector in Nigeria, the provision of the basic safety materials and facilities to workers remains a challenge. The construction industry is believed to be a pillar of domestic economy in most nations; it is believed to contribute about 2.08% to the GDP of Nigeria. Yet, the rate of non-fatal, fatal injuries and illnesses exceeds that of many other industries, the construction industry has the most fatality rate when compared to other industry sectors. This paper examines the level of provision of the basic safety materials and facilities to workers by contractors in the Nigerian construction industry, the study employed the work study and field survey research method. Structured questionnaire were administered to the Architects, Engineers, Project managers and Contractors as well as the workers engaged in construction. The research exposed the neglect in the provision of safety materials and facilities on the part of the contractors. Scaffolds and shovels where the materials readily provided by the contractors from the list of safety materials provided as recommended by the regulatory authorities. The Institute of safety professionals of Nigeria, Council of registered builders of Nigeria and other statutory government agencies should be more diligent to effectively monitor the activities of building construction contractors in Abuja, Nigeria.
Barriers Influencing Construction Firms' Adoption of Emerging Technologies in Supply Chain Management
(School of Environmental Technology, Federal University of Technology Minna, P.M.B 65, Niger State, Nigeria, 2024-10-14) Shehu, Aminu Muhammad; Jimoh, Richard Ajayi; Adefemi, Aka; Olubajo, Oluseun Olukemi
The construction industry plays a critical role in the economic development of nations and efficient supply chain management is crucial to its success. However, the construction sector remains one of the least digitized sectors despite the benefits of emerging technologies This study investigates the barriers influencing the adoption of emerging technologies in construction supply chain management. The study adopted a quantitative approach using a closed ended questionnaire. Data was collected via simple random sampling from 73 construction firms, though 52 were properly filled and returned for the analysis. The data was analysed using mean score item to ascertain the degree to which barriers influence the adoption of emerging technologies by construction firms. The barriers were grouped into three categories, technological, organisational and environmental barriers. The study revealed that the major technological barrier is lack of technical expertise within the organization, organisational barriers is resistance to change from employees and for to environmental regulatory compliance issues. Therefore, it becomes imperative to invest in training and developing partnerships with educational institutions for continuous learning and government to review and update local content requirements to balance domestic growth with technological advancement.
Barriers to the Adoption of Building Information Modelling in Nigerian Construction Industry
(Proceedings of the 1st International Civil Engineering Conference, Department of Civil Engineering, Federal University of Technology Minna, Nigeria, 2018-01-02) Kolo, D. N.; Tsado, T. Y.; Bala, A.; Adinoyi, S. A.; Kolo, D. N.
Building Information Modeling (BIM) involves the development and use of computer generated n-D models to simulate, plan, design, construct, adapt, operate, maintain, renovate, and ultimately beneficially deconstruct a building at the end of its life cycle. BIM represents a new paradigm in construction, it encourages the integration of roles of construction stakeholders enabling them to visualize the project to be built and further identifying potential issues that may occur during the operational phase of buildings. This study assessed the barriers to the adoption of BIM in the Nigerian construction industry and further highlighted ways to improve its adoption. A total of 50 questionnaires were administered to construction professionals in Abuja, Nigeria. Forty (40) retrieved questionnaires were analysed using Statistical Package for social Sciences (SPSS 21) and used for this study, it was revealed that there was generally a low awareness on the use of BIM among construction professionals. The major barrier to using BIM was lack of skilled personnel while the major means of ensuring its adoption was Provision of basic BIM infrastructure. These problems can be effectively tackled by increased support from government and construction industry stakeholders for its use; stressing the benefits derivable, training and retraining of key construction professionals taking into consideration peculiarities to the Nigerian construction industry.
Comparative Analysis of Users’ Rating of the Management Information System Units of Three Universities in North Central Nigeria
(African Journal of Computing & ICT, 2019-09) Daniel Ojonugwa Abutu; Fatimah Jibril Abduldayan; Maryam Lami Abdullahi; Aishat Haruna Abduldayan
This is a comparative analysis of users’ rating of the effectiveness of services provided by the management information system units of three selected Nigerian universities using certain parameters like structural layout, network equipment and security measures, bandwidth and latency, and users’ satisfaction. The selected universities were the Federal University of Technology, Minna (FUTMIN), Baze University, Abuja (BAZEUNI) and University of Abuja (UNIABUJA). Each of these universities has Management Information System (MIS) units that are responsible for managing students’ academic records and personal details. The FUTMIN MIS is characterized by students complaints ranging from delay in connecting to the university network, incorrect students’ records, delay in staff response to queries amongst other. Students’ often wish that they were in other universities that were assumed to offer better services. This study therefore conducted a survey research using a structured questionnaire to gather data on the actual year of establishment of MIS, present composition of MIS users, network infrastructures, security measures, bandwidth and latency of the network, staff strength and area of expertise and future plans from Heads of Information Technology Services (ITS) units in charge of MIS as well as students who are users of the MIS services. Simple percentages and frequency counts were used to report the findings. It was revealed that FUTMIN MIS is not meeting the expectations of its users while BAZEUNI and UNIABUJA performed better at meeting the expectations of their users. The study recommended that FUTMIN ITS unit should organize training and workshop for technical staff, increase the number of ITS staff and network equipment and finally, source for funding from international agencies and donors.
Complementarity of Information Technology to Knowledge Management
(Ahmadu Bello University Library Coplex, A.B.U. Zaria, Nigeria, 2019) Goshie, Rhoda Wusa
Knowledge Management (KM) is presently the key factor for the growth and success of any organization that cannot operate solely by the traditional manual methods. The use of information and communication technologies (ICTs) and the different supporting platforms are dependable for knowledge management to uphold its specific principles, particularly knowledge sharing. The paper identified the significance of information and communication technologies (ICTs) in knowledge Management (KM) to organizational effectiveness.
Delaying transition further with the aid of a short compliant panel in a Blasius boundary layer flow
(The Chinese Society of Theoretical and Applied Mechanics (CSTAM), Fluid Mechanics Division Conference, Guilin, China., 2012-11-12) Bori Ige; Yeo, .K. S.; Dou, .H-S.; Zhao, .X.
The cost of fuelling especially for those in the transport industries could be reduced drastically if there is a means of reducing drag force over their vehicles while in motion. One way to overcome this is to use compliant (membrane) surface; a passive control means which has been proved in various theoretical studies as a promising tool in delaying transition further. In this paper, following the earlier work done on flow over rigid wall within a Blasius boundary layer, we account for the current study carried out on the evolution of pulse-initiated disturbance wavepackets over a finite-length compliant panel by direct numerical simulation (DNS) method. For the single-panel case, a finite section of the wall from X = x/δ0 = 450 -762, was replaced by a tensioned membrane on a viscoelastic foundation, whose properties were designed to inhibit the development of compliant-wall modes. Where δ0 is the displacement thickness at the perturbation location. A small amplitude vertical initiating delta pulse was introduced from the wall streamwise location X0 = 349.4 (x0 = 81cm), and study in detail both spatially and spectrally how the wavepackets generated evolve from the initiating point to the breakdown location over a Blasius boundary layer. The simulation results showed that, the upstream intervention by the finite compliant panel effectively delayed the onset of the incipient turbulent spot by a further distance of Δx = 550, when compared with the rigid wall case results that earlier broke down at X = 1420. This represents an approximately 51% increase in the transition distance measured from the point of wavepacket initiation. Spectral study indicated that the relatively short compliant panel was able to effectively weaken the primary 2-D Tollmien-Schlichting (TS) wave mode, thereby extending the linear regime, so that resultant wavepacket after the panel is dominated by two oblique wave modes and this is the effective strategy of transition delay.
Delaying transition in a Blasius boundary layer with finite compliant panels
(Fourth International Symposium on Bifurcations and Instabilities in Fluid Dynamics (BIFD),, 2011-07-18) Bori Ige; Zhao, .X.; Yeo, .K. S.
Compliant surfaces have been shown to be a promising passive control measure for controlling and delaying boundary layer transition in various theoretical studies [1-2]. In this paper, we report on a recent study we have done on the evolution of pulse-initiated disturbance wavepackets over one or more finite-length compliant panels. The broadband nature of a wavepacket offers a central advantage in permitting natural selection of most dominant waves to operate through the sum of its growth processes. This may be helpful in identifying the critical waves and key processes that are involved at the various stages in natural transition. The initiation, evolution and final breakdown of wavepackets into the incipient turbulent spots in a Blasius boundary layer was modelled by Direct Numerical Simulation (DNS) briefly described in [3]. The comparative evolution and transition performance of three cases are discussed here, namely the rigid-wall case, a single-panel wall and a two-panel wall. In all cases, a fixed vertical-directed delta pulse of small amplitude was initiated at the point x /  349.4, where   2.3182103m is the displacement thickness of the boundary layer at the initiation point. The evolution and breakdown of the wavepacket in a Blasius boundary layer on a rigid wall has already been reported in [3]. For the single-panel case, a finite section of the wall from x /  450 to 762 was replaced by a tensioned membrane on a viscoelastic foundation, whose properties were designed to inhibit the development of compliant-wall modes. The simulation results showed that, the upstream intervention by the finite compliant panel effectively delayed the onset of the incipient turbulent spot by a distance of about 100 cm ( x /  430). This represents an approximately 30% increase in the transition distance measured from the point of wavepacket initiation. Spectral study indicated that the relatively short membrane panel was able to effectively attenuate the primary 2-D Tollmien-Schlichting (TS) wave mode so that resultant wavepacket after the panel was dominated by a pair of oblique waves. Subharmonic secondary instabilities [4-5], which are responsible for nonlinear disturbance wave amplification on a rigid wall, were thus inhibited by the absence or near absence of the 2-D TS wave mode. Staggered Λ-structures and streamwise streaky structures similar to those found in the rigid wall case were observed for the single-panel case, but much further downstream. A second tensioned membrane panel of the same length was added at x /  1359-1658 to form the two-panel case. The last stage of the present simulation shows the wavepacket arriving the location x /  2000 in a perfectly laminar form ( max | u | /U 0.05   ) – this already represents an increase in transition distance of about 50% over the corresponding rigid-wall case. The eventual breakdown location will be further downstream as the wavepacket has not displayed the usual structural features that signify imminent breakdown. This study has shown the efficacy of short compliant panel(s) in controlling and delaying transition.
Design and Fabrication of Rice De-Stoning Machine
(Food Science and Technology, 2014) O. A. Olugboji; J. Y. Jiya
This work aims at meeting the ever increasing demands of quality rice, avoiding losses and improving the income of local farmers. Mild steel was used in the construction of the machine. Standard equations were used to determine the dimension of the parts. The machine is driven by a 1Hp electric motor with 688.17 W required power. The machine has a capacity of 47.39 Kg/hr and an efficiency of 82.47 %