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A short overview of different piezoelectric structures and devices for generating renewable electricity under mechanical actions is presented. A vibrating piezoelectric device differs from a typical electrical power source in that it has capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. Several techniques have been developed to extract energy from the environment. Generally, “vibration energy” could be converted into electrical energy by three techniques: electrostatic charge, magnetic fields and piezoelectric. Mechanical resonance frequency of piezoelectric bimorph transducers depends on geometric size (length, width, and thickness of each layer), and the piezoelectric coefficients of the piezoelectric material. Manufacturing processes and intended applications of several energy harvesting devices are presented.

A short overview of different piezoelectric structures and devices for generating renewable electricity under mechanical actions is presented. A vibrating piezoelectric device differs from a typical electrical power source in that it has capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. Several techniques have been developed to extract energy from the environment. Generally, “vibration energy” could be converted into electrical energy by three techniques: electrostatic charge, magnetic fields and piezoelectric. Mechanical resonance frequency of piezoelectric bimorph transducers depends on geometric size (length, width, and thickness of each layer), and the piezoelectric coefficients of the piezoelectric material. Manufacturing processes and intended applications of several energy harvesting devices are presented.

This study was carried out to reveal the plastic wastes separation practice and disposal mechanism as well as awareness of the negative impact of plastic wastes on the environment, in Makurdi area of Benue State, Nigeria. Questionnaires were administered to 468 individual respondents in 6 sub-locations of the city. Inquisition was also made from 10 hospitals, 6 market centers and the waste management body. The results revealed that 81.2% of the respondents do not separate plastic wastes from other waste stream. All the hospitals and markets do not sort at all. The government agency responsible for the final management of the waste stream does not have a practice of sorting plastic wastes from the whole waste collected with a view to achieving material and energy recovery. The most adopted methods of disposal for plastic wastes by all the stakeholders considered are dumping/burning and dumping. 50.4% of the respondents adopted dumping/burning as a disposal method for plastic wastes while 19.2% burn theirs. Although almost 50% of the population examined for the study claimed to be aware of the dangers of plastic wastes, there is still indifference in the way these wastes are handled as can be observed by the indiscriminate dumping of these wastes, creating litters around the environment. These result revealed a need for the development of a proactive and sustainable management system involving individuals, businesses, hospital managements and waste management body that will protect the environment and enhance resource and energy recovery from plastic wastes.

This study was carried out to reveal the plastic wastes separation practice and disposal mechanism as well as awareness of the negative impact of plastic wastes on the environment, in Makurdi area of Benue State, Nigeria. Questionnaires were administered to 468 individual respondents in 6 sub-locations of the city. Inquisition was also made from 10 hospitals, 6 market centers and the waste management body. The results revealed that 81.2% of the respondents do not separate plastic wastes from other waste stream. All the hospitals and markets do not sort at all. The government agency responsible for the final management of the waste stream does not have a practice of sorting plastic wastes from the whole waste collected with a view to achieving material and energy recovery. The most adopted methods of disposal for plastic wastes by all the stakeholders considered are dumping/burning and dumping. 50.4% of the respondents adopted dumping/burning as a disposal method for plastic wastes while 19.2% burn theirs. Although almost 50% of the population examined for the study claimed to be aware of the dangers of plastic wastes, there is still indifference in the way these wastes are handled as can be observed by the indiscriminate dumping of these wastes, creating litters around the environment. These result revealed a need for the development of a proactive and sustainable management system involving individuals, businesses, hospital managements and waste management body that will protect the environment and enhance resource and energy recovery from plastic wastes.

The aim of the study was the evaluation and comparison of energy potential of briquettes and pellets produced from the maize straw and woody biomass based on various diameters of pellets. By experimental measurements a calorific value and ash content was obser ved. Calorific value was measured by laboratory calorimeter IKA C 6000 (IKA® Works, Inc., USA) and laboratory combustion chamber Lindberg/Blue M (Thermo Fisher Scientific, Inc., USA). Individual calorific values and ash content was observed and subsequentl y confronted to obtain differences with replication. The analysis showed that calorific value of pellets with diameter 6 mm ranged from 16.99 MJ kg - 1 to 17.80 MJ kg - 1 . Calorific value of pellets with 8 mm diameter ranged from 16.63 MJ kg - 1 to 17.20 MJ kg - 1 . However, compared calorific value of briquettes ranged from 14.99 MJ kg - 1 to 15.66 MJ kg - 1 . Further analysis showed that ash content of samples varied as well and it’s even affected by diameter of pellets. While ash content of pellets with diameter 6 mm was observed as 4.9% of total volume in case of pellets with 8 mm it was observed at value 5.5%. Briquettes produced from maize straw have ash content at value 5.4%. In contrary, ash content of woody biomass was significantly higher, 11% of volume, specifi cally. At the basis of observed parameters it can be concluded that maize straw densified in form of briquettes and pellets have a great energy potential which is comparable and competitive with currently used materials for production of briquettes and pellets.

The aim of the study was the evaluation and comparison of energy potential of briquettes and pellets produced from the maize straw and woody biomass based on various diameters of pellets. By experimental measurements a calorific value and ash content was obser ved. Calorific value was measured by laboratory calorimeter IKA C 6000 (IKA® Works, Inc., USA) and laboratory combustion chamber Lindberg/Blue M (Thermo Fisher Scientific, Inc., USA). Individual calorific values and ash content was observed and subsequentl y confronted to obtain differences with replication. The analysis showed that calorific value of pellets with diameter 6 mm ranged from 16.99 MJ kg - 1 to 17.80 MJ kg - 1 . Calorific value of pellets with 8 mm diameter ranged from 16.63 MJ kg - 1 to 17.20 MJ kg - 1 . However, compared calorific value of briquettes ranged from 14.99 MJ kg - 1 to 15.66 MJ kg - 1 . Further analysis showed that ash content of samples varied as well and it’s even affected by diameter of pellets. While ash content of pellets with diameter 6 mm was observed as 4.9% of total volume in case of pellets with 8 mm it was observed at value 5.5%. Briquettes produced from maize straw have ash content at value 5.4%. In contrary, ash content of woody biomass was significantly higher, 11% of volume, specifi cally. At the basis of observed parameters it can be concluded that maize straw densified in form of briquettes and pellets have a great energy potential which is comparable and competitive with currently used materials for production of briquettes and pellets.

This work aims at studying the importance and the efficiency of energy use in a few palm kernel oil mills selected for their representativity. Pattern of energy use, the cost of energy per unit product, energy intensity and normalized performance indicator (NPI) were determined. Results show that the medium and the large mills depend largely on fossil fuel; while the small mill depends on electricity. It was found out that the large mill has the most effective use of energy with high energy intensity. The annual cost of energy per unit product of N8,360,000 ($64,307.69); N12,262,250 ($94,325) and N13,353,870 ($102, 722.08) were obtained for small, medium and large mills respectively. The NPI results show that there was no wastage of energy through space heating in energy supplied for production within the factory site.

This work aims at studying the importance and the efficiency of energy use in a few palm kernel oil mills selected for their representativity. Pattern of energy use, the cost of energy per unit product, energy intensity and normalized performance indicator (NPI) were determined. Results show that the medium and the large mills depend largely on fossil fuel; while the small mill depends on electricity. It was found out that the large mill has the most effective use of energy with high energy intensity. The annual cost of energy per unit product of N8,360,000 ($64,307.69); N12,262,250 ($94,325) and N13,353,870 ($102, 722.08) were obtained for small, medium and large mills respectively. The NPI results show that there was no wastage of energy through space heating in energy supplied for production within the factory site.

This paper presents a feasibility study of a mini-hydroelectric power plant for seasonal base load at the main campus of University of Abuja, along Airport Expressway, Abuja, Nigeria. The study was premised on the need to mitigate the insufficient electricity supply being experienced by the University. The use of backup diesel and petrol generating sets was noted to increased the overall operating costs of the University due to the need to purchase fuel, in addition to the associated maintenance cost. The presence of River Wuye within the University brought to fore the need to explore the establishment of a hydropower plant as an alternative means of mininmizing the energy shortage. The methodology adopted included determination of the University electricity demand using clamp-on meter, determination of the river run-off via data obtained from Nigerian Meteorological Agency (NIMET), flow rate with the use of float and river geometry, while the head was obtained by Global Positioning System (GPS). Furthermore, the hydroelectric power potential, site layout for equipment installation and project cost were determined. The results indicated that the monthly lowest energy consumption (base load) at the University during the period of study was at 667 kW, while the highest (peak) load was 883 kW. River Wuye assessment favoured conventional hydro power plant instead of hydro power plant technologies with out dam such as paddle wheel system as Giri river flow was low and seasonal. River Giri has run-off of 1,330 mm with the proposed dam estimated to have height and length of 10 m and 120 m, respectively. River Wuye has a flow rate of 14.5 m3/s, maximum head of 10 m and hydropower potential of about 855 kW. The cost of the proposed hydro power plant ranged from 80.3-615.6 million Naira (N) (equivalent to N93,960/kW- N720,000/kW or $261/kW-$2000/kW).The range arose due to variation on cost of refurbished or new turbine-generator system and civil works. The electricity generation unit cost from the hydropower plant is expected to be N24.74-50.14/kWh. This feasibility work is significant as it will aid commencement of detailed project report (DPR) that will highlight detailed study of hydrology and geology, environmental impact assessment, flood control and weir structures for a hydropower plant on River Wuye at 885 kW. In addition, when River Wuye has low flow, wind and solar power plants could be deployed to provide the shortfall in electricity supply to the University