Subjects -> ENGINEERING (Total: 2791 journals)
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    - ENGINEERING (1402 journals)
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    - MECHANICAL ENGINEERING (115 journals)

ENGINEERING (1402 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 2)
3D Research     Hybrid Journal   (Followers: 17)
AAPG Bulletin     Hybrid Journal   (Followers: 9)
Abstract and Applied Analysis     Open Access   (Followers: 1)
Aceh International Journal of Science and Technology     Open Access   (Followers: 3)
ACS Nano     Hybrid Journal   (Followers: 189)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8)
Acta Nova     Open Access  
Acta Polytechnica : Journal of Advanced Engineering     Open Access  
Acta Universitatis Cibiniensis. Technical Series     Open Access   (Followers: 1)
Active and Passive Electronic Components     Open Access   (Followers: 5)
Additive Manufacturing Letters     Open Access   (Followers: 7)
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Energy and Sustainability Research     Open Access   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 10)
Advanced Engineering Research     Open Access  
Advanced Journal of Graduate Research     Open Access   (Followers: 1)
Advanced Quantum Technologies     Hybrid Journal   (Followers: 1)
Advanced Science     Open Access   (Followers: 12)
Advanced Science Focus     Free   (Followers: 5)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 3)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 19)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advances in Applied Energy     Open Access   (Followers: 6)
Advances in Catalysis     Full-text available via subscription   (Followers: 7)
Advances in Complex Systems     Hybrid Journal   (Followers: 10)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 27)
Advances in Natural Sciences : Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 13)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 50)
Advances in Remote Sensing     Open Access   (Followers: 58)
Advances in Science and Research (ASR)     Open Access   (Followers: 8)
Aerobiologia     Hybrid Journal   (Followers: 2)
Aerospace Systems     Hybrid Journal   (Followers: 7)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 7)
AIChE Journal     Hybrid Journal   (Followers: 31)
Ain Shams Engineering Journal     Open Access   (Followers: 1)
Al-Nahrain Journal for Engineering Sciences     Open Access  
Al-Qadisiya Journal for Engineering Sciences     Open Access  
AL-Rafdain Engineering Journal     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 21)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 7)
American Journal of Engineering Education     Open Access   (Followers: 13)
American Journal of Environmental Engineering     Open Access   (Followers: 6)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Annals of Civil and Environmental Engineering     Open Access   (Followers: 2)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 9)
Annual Journal of Technical University of Varna     Open Access  
Antarctic Science     Hybrid Journal   (Followers: 1)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applications in Energy and Combustion Science     Open Access   (Followers: 2)
Applications in Engineering Science     Open Access  
Applied Catalysis A: General     Hybrid Journal   (Followers: 7)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 16)
Applied Energy     Partially Free   (Followers: 25)
Applied Engineering Letters     Open Access  
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Network Science     Open Access   (Followers: 2)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Applied Physics Research     Open Access   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 1)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 10)
Arctic     Open Access  
Arid Zone Journal of Engineering, Technology and Environment     Open Access  
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access  
Asian Journal of Applied Science and Engineering     Open Access  
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 5)
Assembly Automation     Hybrid Journal   (Followers: 2)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
AURUM : Mühendislik Sistemleri ve Mimarlık Dergisi = Aurum Journal of Engineering Systems and Architecture     Open Access   (Followers: 1)
Australasian Journal of Engineering Education     Hybrid Journal   (Followers: 3)
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Hybrid Journal  
Autocracy : Jurnal Otomasi, Kendali, dan Aplikasi Industri     Open Access  
Automotive and Engine Technology     Hybrid Journal  
Automotive Experiences     Open Access  
Automotive Innovation     Hybrid Journal  
Avances en Ciencias e Ingenierías     Open Access  
Avances: Investigación en Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 2)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 6)
Batteries     Open Access   (Followers: 8)
Batteries & Supercaps     Hybrid Journal   (Followers: 5)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 27)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access  
Beyond : Undergraduate Research Journal     Open Access  
Bhakti Persada : Jurnal Aplikasi IPTEKS     Open Access  
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access  
Bilge International Journal of Science and Technology Research     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Hybrid Journal   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 11)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 3)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 4)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomicrofluidics     Open Access   (Followers: 7)
Biotechnology Progress     Hybrid Journal   (Followers: 42)
Black Sea Journal of Engineering and Science     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access  
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 12)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 15)
Cahiers Droit, Sciences & Technologies     Open Access   (Followers: 1)
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 28)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 51)
Carbon Resources Conversion     Open Access   (Followers: 2)
Carpathian Journal of Electronic and Computer Engineering     Open Access  
Case Studies in Thermal Engineering     Open Access   (Followers: 9)
Catalysis Communications     Hybrid Journal   (Followers: 7)
Catalysis Letters     Hybrid Journal   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 4)
CEAS Space Journal     Hybrid Journal   (Followers: 6)
Cell Reports Physical Science     Open Access  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
CFD Letters     Open Access   (Followers: 7)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals : X     Open Access   (Followers: 1)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 1)
Chinese Journal of Population, Resources and Environment     Open Access  
Chinese Science Bulletin     Open Access  
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Hybrid Journal   (Followers: 10)
CIRP Journal of Manufacturing Science and Technology     Hybrid Journal   (Followers: 12)
City, Culture and Society     Hybrid Journal   (Followers: 23)
Clay Minerals     Hybrid Journal   (Followers: 7)
Cleaner Engineering and Technology     Open Access   (Followers: 5)
Cleaner Environmental Systems     Open Access   (Followers: 5)
Coastal Engineering     Hybrid Journal   (Followers: 16)
Coastal Engineering Journal     Hybrid Journal   (Followers: 7)
Coastal Engineering Proceedings : Proceedings of the International Conference on Coastal Engineering     Open Access   (Followers: 1)
Coastal Management     Hybrid Journal   (Followers: 29)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 2)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 18)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 21)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 246)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 179)
Composites Part B : Engineering     Hybrid Journal   (Followers: 224)
Composites Part C : Open Access     Open Access   (Followers: 1)
Composites Science and Technology     Hybrid Journal   (Followers: 151)
Comptes Rendus : Mécanique     Open Access   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Computational Optimization and Applications     Hybrid Journal   (Followers: 9)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 15)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 8)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 7)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 31)
Conciencia Tecnologica     Open Access  
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 46)

        1 2 3 4 5 6 7 8 | Last

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Journal Cover
Arid Zone Journal of Engineering, Technology and Environment
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1596-2490 - ISSN (Online) 2545-5818
Published by University of Maiduguri Homepage  [1 journal]
  • Infiltration capacity of compacted lime treated black cotton soil as
           hydraulic barrier material

    • Authors: A. N. Alkali, I. M. Shettima, B. B. Kurna , N. Y. Okunade
      Pages: 261 - 268
      Abstract: Studies have shown the effect of hydraulic barriers in the reduction in movement of leachates, that have the potential of contaminating groundwater. Laboratory tests were conducted on black cotton soil treated with up to 5% lime by dry weight to assess its suitability in waste containment facilities. The test samples were subjected to particle size distribution analysis, consistency limit tests, compaction and hydraulic conductivity. The compaction energy of British Standard Light (BSL) was employed. The study showed decrease in liquid limit from 65.20% to 56.30% and plasticity index from 41.50% to 28.58% while plastic limit increased from 23.70% to 27.72% with the increase lime content.  Maximum Dry Density (MDD) increases with increased in lime from 1.78  to 1.88 g/cm3 whereas the Optimum Moisture Content (OMC) decreased from 19.79% to 15.39%. Hydraulic conductivity of black cotton soil treated with percentage of lime content 0%, 1%, 3% and 5% of the soil weight examined for a period of 28days. The hydraulic conductivity value of natural soil was 1.65E-08 and decreased to 3.71 E-09 m/s at 5% lime content. Therefore, it is clear that hydraulic conductivity decreases with percentage increase in lime content. It is recommended that volumetric shrinkage, free swell and unconfined compressive strength should be carried out.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Development of a windmill for pumping water using positive displacement

    • Authors: B. Alkali, B. S. Elkanah, S. G. Amarem, A. B. Hassan, N. S. Gukop, E. A. P. Egbe
      Pages: 269 - 278
      Abstract: The abundant renewable energy sources have not been harnessed  for electricity and other uses to date. Wind speed is high in the Northern part of Nigeria and therefore require utilization so as to reduce the use of harmful non-renewable energy sources. In this work wind energy was used to drive a windmills that provide mechanical energy directly for a borehole with a positive displacement pump with a 2.5ft stroke. The design analysis of the wind mill was carried out numerically based on the wind data collected. The proposed design were fabricated using designed dimensions. The rotary motion of the shaft were converted to a linear motion using slider-crank mechanism. The designed horizontal axis windmill has 3 blades has three blades driving the shaft. Also the kinematic modelling of the mechanism was carried out. The assembled windmill was tested and was found to have an operated efficiency of 58.2%.  
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Solid Waste Generation and Characterization in Ilorin, Nigeria

    • Authors: O. A. Mokuolu, J. O. Iji, S. A. Aremu
      Pages: 279 - 288
      Abstract: Global per capita waste generation rates and characterization vary by regions, countries, and within cities. The generation, l and characterization of waste from selected areas in Ilorin, Nigeria, prone to indiscriminate disposal of solid waste without consequence were analyzed for proper management. Municipal solid wastes were sorted, analyzed by weight and percentage composition using the quantitative approach. The average generated waste per capita was estimated to be  0.66 kg/day, w/w distribution was 57.53% food waste, 9.07% nylon (flexible films), 5.98% plastic (rigid containers),4.95% textile, 10.51% paper and 11.96% others. The average moisture content was 46.16% food waste, 20.63% nylon, 18.65% plastic, 36.67% textile, 18.45% paper and 42.89% others. The results show an average bulk density of 10.36 Kg/m3 of food waste,  2.14 of nylon, 0.5 of plastic; 0.93 of textile; 2.74 of paper and others 5.36. The chemical analysis showed that volatile matter ranged from 20.55 to 24.10%, ash content 3.10to 3.90%, fixed carbon 7.5to 9.8%, calorific value 14820to 18360 (kJ/kg), nitrogen 0.40to 0.50%, hydrogen 4.38to 5.80%, carbon 40.90 to 44.30%, oxygen 30.80 to 34.60%, Sulphur 0.19 to 0.24%, fusing point of ash 3.12to 4.38 °C, and heating value from 13.520to 13.64 KJ/Kg. The results generated could play a positive role in the  management of solid waste in that area.  
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Development of an improved acm scheme for mitigating earth-to-space
           propagation effects

    • Authors: A. M. S. Tekanyi, R. M. Idris, A. D. Usman, Z. M. Abdullahi , E. E. Agbon
      Pages: 289 - 300
      Abstract: In satellite communications, the communication link experiences propagation losses such as: Path loss, atmospheric losses, rain fading, ionosphere effects (such as scintillation), and other effects which can greatly affect the received signal strength and close the link budget in the worst case. The design of future broadband satellite systems has to be done with the challenge of more complex traffic mix and these harsher propagation conditions which mitigate the performance of the communications link. Link adaptation (LA) has been used in satellite communications applications for evaluating the performance of an adaptive modulation system in the unique space-based propagation environment. Despite the current research on improving satellite system performance, there is still a need to further develop a scheme that mitigates the effect of atmospheric impairments. This work develops an improved adaptive coding and modulation scheme that mitigates earth-to-space propagation effects. The scheme targets maximizing data throughput while staying below a Bit Error Rate (BER) threshold so as to successfully mitigate link impairment in fixed communication systems. Simulation of the work is carried out using MATLAB 2016b and System Toolkit (STK) 11.3. Simulation result showed that the iACM scheme was able to reduce the effect of path loss in time by 5% over the ACM scheme and also reduced the effect of path loss with respect to the angle of elevation by 2% over the ACM scheme and improvement in the network energy to noise ratio by 22.74% over ACM. In terms of system throughput, the iACM scheme showed an improvement in throughput by 24% over the ACM scheme. Finally, the iACM scheme has shown better performance in terms of throughput and thus, improve the performance of satellite communication.

      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Influence of energy recovery system on the energy efficiency of a flat-bed
           dryer in the drying of turmeric

    • Authors: E. A. Adu, T. Pandiarajan, W. Farzana, K. A. K. Abba
      Pages: 301 - 316
      Abstract: Drying is one of the most energy intensive unit operations in agricultural and food processing industry. Energy costs represent a major fraction of cost of operation of a mechanical dryer, therefore, the more efficient a dryer uses its energy supply, the lesser its cost of operation and the better it impacts on profitability of drying process. A flat-bed dryer of 25kg capacity was developed and fitted with air-to-air indirect mixing heat exchanger (Heat Recovery Unit, HRU) at the vent of the drying chamber. The dryer was tested to determine the impact of exhaust vent waste heat recovery on its energy efficiency and cost of operation. Turmeric, an important spice crop was dried at three temperatures of 60°C, 65°C, and 70°C under two operating conditions; (i) without HRU (C-I) and (ii) with HRU (C-II). The result show thermal efficiency, at C-I it was found to be 28%, 27% and 27% at 60°C, 65°C and 70°C respectively and for C-II it was 42%, 42%, and 40% at 60°C, 65°C, and 70°C respectively. This indicates that  the overall thermal efficiency was improved by 15% for C-II at 65°C as compared to C-I at 65°C. ANOVA show there is significant different (P< 0.05) between C-II and C-I as regards thermal efficiency. The result also showed that specific energy consumption was reduced for all drying temperatures levels of C-II as compared to C-I and the result shows that testing condition C-II, at 65°C has the lowest specific energy consumption of 1.79(kWh/kg) while C-I at 60°C has the highest value; 2.37 (kWh/kg), this showed significant different (P< 0.05).Drying curves of turmeric were plotted and it was found that C-II performed better in drying turmeric since the moisture lose was faster than in C-I and the drying time was lowered by 4hrs for C-II at 65°C compared to C-I 65°C. The average Return on Investment (ROI) of HRU was calculated considering average of 260 working days or 130 batch drying operation per annum with one drying cycle per two working days and was found to be 0.61 and the payback period was 19 months. It was concluded that the developed flatbed dryer can be used to dry 25 kg of turmeric per batch in 25 hours drying time using operating condition C-II, 65°C which showed better quality in terms of energy efficiency and drying rate.  
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Mathematical prediction of nitrogen and phosphorus removal from piggery
           wastewater by horizontal sub-surface flow constructed wetland.

    • Authors: I. J. Udom
      Pages: 317 - 334
      Abstract: Mathematical equations were derived for estimation of nitrogen and phosphorus removal from piggery wastewater in horizontal subsurface flow constructed wetlands. The model inputs included wastewater inflow, retention, plant uptake and nutrient loss to the atmosphere by volatilization of nitrogen. Plant die off, precipitation and exchange with subsurface were considered negligible. The calibration and validation of the model was carried using different sets of experimental data generated from a pilot constructed wetland monitored over a period of seven months. The results show that the amount of nitrogen and phosphorus concentrations decreased exponentially within three days of retention in the wetland and, thereafter, the reduction appeared constant over higher retention time subject to the decay coefficient. There was high correlation between the simulated and observed parameters with R2 = 0.9537 for nitrogen and 0.9912 for phosphorus respectively. The low values of the mean bias error (ME) of 0.211 and 0.139, root mean square error (RMSE) of 0.32 and 0.18, and relative error of RE of 24 and 12%, demonstrated the ability of the model to predict nutrient removal accurately. The models efficiencies of 84 and 77% and index of agreements of 0.6527 and 0.8676 for nitrogen and phosphorus respectively, indicate an acceptable level of the models predictive capacities. The linear regression coefficients appear reasonable given that the system was a natural system located in the field, where uncontrolled influencing factors could weaken optimal performance. Because of challenges associated with Scaling-up this result.  longer field studies are recommended. The models developed in this study considered the features of horizontal-subsurface-flow constructed-wetlands for removal of nitrogen and phosphorus from piggery wastewater. The high correlation between the developed models and the calibrated parameters showed that they are rational. The models can be used to simulate nitrogen and phosphorus removal in horizontal-subsurface-flow constructed-wetlands. The performance of these models meets the water quality discharge or reuse standards of Nigeria for wastewater discharge to land and surface water.  
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Factors Affecting Time Performance of Tertiary Education Trust Fund
           Construction Projects in North-East, Nigeria

    • Authors: M. M. Mukhtar, D. Abdussalam, M. M. Mustapha
      Pages: 335 - 346
      Abstract: Higher education institutions in Nigeria faced with the challenges of inadequate funding for the provision of facilities and rehabilitation of decaying ones. To address this issue, the Tertiary Education Trust Fund (TETfund) was established. However, it has been reported that, there are poor time performance of TETFund projects in tertiary institutions in Nigeria. This study was conducted to determine factors affecting time performance of Tertiary Education Trust Fund construction projects in north-east, Nigeria. Thirty-two (32) factors causing delay in construction projects were identified from the literature review. Data collection was carried out by means of survey questionnaire. One hundred and thirty-six questionnaires (136) were shared among construction professionals comprising of clients, contractors and consultants, 112 were returned completed representing 82% response rate. The data collected were analysed by means of frequency, severity index and Spearman’s rank correlation. The results obtained revealed that, the most common delay factor in TETFund construction projects according to the three categories of the respondents is late procurement of materials. Similarly, there is consensus among the three categories of the respondents that type of project bidding and award is one of the most severe delay factors in TETFund projects. Clients and consultants pointed out that, factors with high impacts on time performance include ineffective planning and scheduling of project by contractor, poor site management and supervision by contractor, and shortage of qualified workers. Whereas, based on contractors’ views, delay in progress payments by client has the highest impact. The study recommended that adequate planning and scheduling for all activities of project should be done by contractors at an appropriate time. The findings of this study can assist TETFund construction project team members to understanding factors that can significantly affect timely delivery of their projects.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Modelling Self Purification of River Benue within Makurdi.

    • Authors: I. M. Aho, G. D. Akpen , C. C. Aniakor
      Pages: 347 - 356
      Abstract: This study considered biochemical oxygen demand (BOD), dissolved oxygen (DO), the re- oxygenation rate, the de-oxygenation rate, the self-purification rate model for River Benue within Makurdi reach. The hydrodynamic data were collected while re-oxygenation rate, de-oxygenation rate and self purification rate were calculated using DO and BOD at 14 different stations along the river stretch. An empirical model for self purification was generated analytically using multiple linear regression equation analysis. The pH varied from 6.8 to 8.08 while DO concentration between 4.0 mg/L and 6.3 mg/L; BOD concentration ranges from 1.0 mg/L to 2.0 mg/L; Mean re-oxygenation rate of 0.179 in the raining season and 0.1 in the dry season; Mean de-oxygenation rate of 0.1186 day-1 in the raining season and 0.1345 day-1in the dry season was calculated; Self purification coefficient had a mean value of 1.3398 in dry season and 0.8354 in rainy season;  The model has coefficient of determination (R2) and adjusted R2 of 0.5691 and 0.5469 respectively; a multiple correlation coefficient of 0.7544 and root mean squared error of 0.2433 between the observed field data and the model data. In conclusion, the river has good self purification ability and the model generated is reliable considering the root mean squared error.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Cranfield University and University of Maiduguri CubeSat (CUUMcube) for
           Technology Demonstration: Baseline and Mission Design

    • Authors: M. I. Ishaq, R. A. Kyari, I. Halliru, C. N. Amulah
      Pages: 357 - 370
      Abstract: CubeSats are small satellites that can be deployed to orbit to achieve various space mission goals. Lately, there are several CubeSat launch opportunities from the International Space Station (ISS). For University of Maiduguri to be able to bid for such launch opportunities there is a need for a baseline for a spacecraft and a mission design. Thus, this paper using the Systems Engineering approach is a baseline and mission design for a CubeSat using CubeSat COTS (commercial off-the-shelf) components targeting the KiboCUBE opportunity. CUUMcube mission is a technology demonstration mission to fly two payloads, Cranfield’s Acoustic Sensor and De-Orbit Mechanism (DOM). The Acoustic Sensor is a microphone that measures vibrations, it is intended to measure vibrations due to: spacecraft thermal cycling mechanical noise, antenna deployment, Micrometeoroids and Orbital Debris (MMOD) impacts, DOM deployment and changes in acoustic response of spacecraft after deployment of both mechanisms. The DOM is a deployable drag sail, a passive method of removing spacecraft from orbit afterlife in the effort of mitigating space debris. Thus, mission baseline reached after the design is to deploy a 1U CubeSat, to carry two payloads (Cranfield’s Acoustic Sensor and DOM), using COTS components. The deployment of the spacecraft will be from the ISS into an elliptical orbit (perigee: 380km, apogee: 420 km). The ground control stations are COTS component too, where there will be one each in UK and Nigeria. Lastly, 30 mins after deployment into orbit the mission sequence starts from the activation of spacecraft to 24 hours recording mode to monitoring mode by the acoustic sensor to capturing of vibrations. Hence, the antenna and the DOM will be deployed. The DOM will speed the orbit decay of the spacecraft, as a result it will speed the re-entry phase and burn in the process.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Propagation Loss Determination of GSM Signal Strength in Selected
           Buildings in Ilorin, Nigeria

    • Authors: J. Akanni, O. T. Oraiye, A. A. Isa, O. Ogunbiyi
      Pages: 371 - 380
      Abstract: GSM signal building penetration loss is a problem often encountered by subscribers inside a building. As a result of building penetration loss, poor reception and signal outages often occur in many indoor locations and this accounts for increased attenuation of received signal strength of a cellular network signal when a subscriber with a mobile phone moves from outdoor to indoor. The study assessed the GSM signal penetration loss in thatched, wooden, block, mud and zinc buildings. Three network providers named A, B and C was used for the experiment. A low budget but very effective equipment (Two Tecno Pouvoir 3 plus Android phone) was used as the measurement tool. It was loaded with Network Signal Info application developed by KAIBITS Software GmbH installed software and positioned inside and outside the building to record indoor and outdoor GSM signal strength respectively for the three service providers in Ilorin, Nigeria. The results were then analyzed in order to determine and compare the path loss introduced by each of the selected buildings. This process was repeated for all the selected buildings, and the measurement was carried out for 6 months. The findings revealed that the outdoor signal strength was higher than the indoor signal strength for all the selected buildings; it also revealed that penetration loss is likely to be a function of the material used in the construction of the buildings. Zinc building has the highest penetration loss of 12.0dBm and thatched building has the least penetration loss of 2.6dBm. Information from this research will assist in selection of building materials for good indoor cellular network signal reception. It will also assist cellular network service providers in the link budget preparation for environments where similar building materials are used.  
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Assessment of energy potential of municipal solid waste from university of
           derby student residence

    • Authors: N. S. Gukop, J. A. Japhet, B. D. Lengs, A. Adesanmi
      Pages: 381 - 388
      Abstract: Solid waste generated from the University of Derby Student Residence was used to examine the amount of thermal energy that can be reclaimed from the waste. The waste material used for the analysis was categorized into different constituents which were used for analyzing the sample, from which the recoverable energy was estimated. The calorific value of the waste mixture was found to be 34.28 MJ/kg with a corresponding thermal energy recoverable estimated to be 1532.96 MJ/day, which gave an equivalent power of 425.82 kWh/day. The findings from this study suggests the necessity for the adoption of waste management systems that will integrate energy recovery from wastes in order to supplement the increasing demand for energy.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Strength properties and microstructural characterization of metakaolin
           geopolymer concrete synthsized at ambient temperature.

    • Authors: C. H. Salihu, A. E. Abalaka, R. A. Lafiya-Araga, B. J. Olawuyi, I. Kariim
      Pages: 389 - 402
      Abstract: Geopolymer concrete has been gaining extensive attention in recent years due to its numerous advantages over Ordinary Portland cement concrete in terms of reduced carbon footprint, improved mechanical strength, durability as well as chemical resistance. However, production of geopolymer concrete is usually affected by several factors such as the synthesis temperature, nature of the source material and the type of alkaline activator used. For these materials to have wider application within the Nigerian construction industry, there is a need to synthesize the concrete at ambient temperature and to examine the suitability of native Alkaleri kaolin to produce geopolymer concrete. The study presents the strength and microstructural properties of Metakaolin Geopolymer Concrete synthesized at ambient temperature. Alkaleri calcined kaolin from Bauchi state Nigeria was used as the main geopolymer precursor with sodium hydroxide and sodium silicate as the alkaline activating agent.  The Geopolymer concrete was prepared with Silicon/Aluminium ratio of 2.0 and 2.5 (Geopolymer concrete M1 and M2 respectively) and cured for 3, 7, 14, 28, and 90 days at ambient condition (average temperature of 26°C and average relative humidity of 61± 15%). Fourier Transform Infra-Red, X-ray Diffraction, Thermo-Gravimetric Analysis, Scanning Electron Microscopy as well as compressive strength and split tensile strength test were conducted on the Geopolymer concrete at appropriate curing age to examine their microstructure and strength properties. The Fourier Transform Infra-Red revealed that there was an immediate geopolymeric reaction between the metakaolin and the alkali activator. The X-ray Diffraction showed that the raw metakaolin sample and both Geopolymer concrete M1 and M2 were amorphous in nature; while the Geopolymer concrete M2 (Silicon/Aluminium ratio of 2.5) exhibited good dissolution of the kaolinite which resulted in a more compact and stable structure in comparison with Geopolymer concrete M1 (Silicon/Aluminium ratio of 2.0). This was also confirmed by the Scanning Electron Microscopic images of the Geopolymer concretes.  The Thermo-Gravimetric Analysis revealed that both Geopolymer concrete M1 and M2 were thermally stable at 300°C and at 800°C, only the organic phase of the geopolymer decomposed. The strength properties (compressive and tensile strength) of Geopolymer concrete M1 and M2 increased with increase in the curing age, and Geopolymer concrete M2 displayed slightly higher strength in all the curing ages as compared with the Geopolymer concrete M1. This implies that the higher the Silicon/Aluminium ratio, the higher the mechanical strength of the geopolymer. Both the Geopolymer concrete samples attained a compressive strength that can be acceptable for structural use as normal strength concrete grade C20/25 as specified in the requirement of BS EN 206-1 2000 at 28 days curing.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Analysis of the Seasonal Variation in Turbidity Index in Sudan and Fresh
           Water Swamp Vegetation Zones, Nigeria

    • Authors: S. U. Muhammad, W. C. Solomon, D. B. Yahaya, J. S. Enaburekhan
      Pages: 403 - 414
      Abstract: This study evaluates the seasonal turbidity index of two vegetation zones in Nigerian which are Sudan and Fresh water swamp. Thirty years (1981 – 2010) meteorological data of temperature, relative humidity and solar radiation were obtained from the archives of the Nigerian Meteorological agency (NIMET). Annual and monthly analysis of the turbidity coefficients were mainly based on the Linke and Angstrom methods, due to absence of radiosonde data. The results show that the monthly mean values of the clear-sky global radiation lies between 19.34 MJ/m2day to 24.44 MJ/m2day (for Sudan vegetation) and 15.54 MJ/m2day to 20.28 MJ/m2day (Fresh water swamp). Meanwhile, the monthly percentages of clearness index above 0.6 were estimated as 75% and 33.3, and for the water vapour content exceeding 3 cm to be 58.3% and 100%, for the Sudan and Fresh swamp vegetation, respectively.  These values contribute significantly to the reduction of direct radiant energy. The results obtained for the seasonal index for Linke and Angstrom coefficients show that for the wet season, the index exceeded the dry value by 25.99% and 23.66% for Sudan and Fresh swamp vegetation, respectively. By implication, the Fresh water Swamp is laden with more aerosols than Sudan zone. Additionally, the R2 obtained for the relationship between Angstrom and Linke is 0.999 for both locations. Hence, the study provides an insight into the contribution of aerosol in the attenuation of solar radiation over the atmosphere for these locations.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
  • Prediction of mass and volume of Tacca involucrata tubers using physical

    • Authors: A. O. Raji , B. O. Oyefeso
      Pages: 415 - 428
      Abstract: Knowledge of physical properties of crops is necessary for the development of processing machines. Relationships between the various physical properties of crops could also be useful in ensuring proper handling and more efficient design of processing machineries. This study was therefore, aimed at developing mathematical models for predicting the mass and volume of Tacca involucrata tubers using some physical characteristics of the crop. Physical characteristics of Tacca tubers at average moisture content of 73.3% (wet basis) namely axial dimensions, Arithmetic Mean Diameter (AMD), Geometric Mean Diameter (GMD), projected areas along the three mutually-perpendicular axes, criterion area (Ac), mass and volume were determined. Out of 240 samples used in the study, data from 120 samples were used for development of the prediction models while the remaining were used for validation of the developed models. Data analysis tool in Microsoft Excel (2013 version) was used to carry out regression analysis and develop the predictive models. Statistical parameters namely correlation coefficient, coefficient of determination, root mean square error and mean bias error were used to determine the goodness of fit of the predictive models. The mass and volume models were divided into three classifications namely: single and multiple variable regression models based on axial dimensions; single and multiple variable regression models based on the projected areas; single variable regression model based on volume (for mass prediction only). Average length, width, thickness, AMD and GMD of the tubers were 71.88, 57.22, 46.71, 58.60 and 57.57 mm respectively while average criterion area, longitudinal, cross-sectional and transversal projected areas were 2614.24, 2580.61, 2097.04 and 3165.07 mm2 respectively. Average mass and volume of the tubers were 129.30 g and 111.55 cm3 respectively.  All the developed models performed well in predicting the mass and volume of Tacca tubers (R2 ≥ 0. 905) except for those based on the axial dimensions as single independent variables (R2 ≤ 0.890). The predicted mass and volume of Tacca tubers were not significantly different (p ≤ 0.05) from the experimentally observed values for all the classifications considered. Mass and volume modelling based on a single variable of any of the projected areas was the most convenient modelling for Tacca tubers since it involves the use of a single image capturing device and the whole measurement could therefore, be automated. The developed models would be useful for automated sorting and packaging of Tacca tubers.
      PubDate: 2021-09-01
      Issue No: Vol. 17, No. 3 (2021)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Tel: +00 44 (0)131 4513762

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