Distribution, pollution index and associated health risk of trace metals in waste-impacted soils within Akwa Ibom State, Nigeria

G. A. Ebong,H. S. Etuk,E. U. Dan 한국자원공학회 2018 Geosystem engineering Vol.21 No.3

This research assessed the level, source and associated health risks of trace metals in waste-impacted soils within Nigeria. Results reported revealed that mean concentrations for all the metals studied were higher than their levels in control. The mean concentrations of all the metals except Ni were also higher than their recommended limits for Nigerian soil by Federal Environmental Protection Agency. Pollution assessment of these trace metals and different locations studied indicated that Pb and Cd were metals with very high contamination status. Results obtained indicated that concentrations of Fe and Ni were mainly from natural geological processes while Pb, Cd and Cu were from anthropogenic source. Principal component analysis revealed human activities as the major factor for the presence of these metals at the different locations studied. This study identified Ibeno and Uyo as locations with very high soil contamination. Hierarchical clusters and Pearson correlation analyses showed variable relationship among the different locations and metals studied. Results obtained indicated that children in Ibeno and Uyo are in a very high risk developing health problems associated with Pb and Cd. The analytical procedures and results obtained were validated using SRM 2710a (Montan 1 soil.) from NIST, U.S.A.

On Electroless Plating and Double Sided Buried Contact Silicon Solar Cells

Ebong, A.U.,Kim, D.S.,Lee, S.H.,Honsberg, C.B. Materials Research Society of Korea 1996 한국재료학회지 Vol.6 No.6

The double sided buried contact(DSBC)silicon solar cell processing requires doping of the rear and front grooves with boron and phosphorus respectively. The successful electroless plating of these grooves with the appropriate metals haave been found to depend on the boron conditions for the rear fingers. However, an increased understanding of electroless plating has removed this restriction. Thus the DSBC cells using different boron conditions can be electrolessly plated with ease. This paper presents the recent work done on metallizing the double sided buried contact silicon solar cells with heavily doped boron grooves. The cells results indicate that, the heavier the boron grooves, the poorer the cell performance because of the probable higher metal contact recombination associated with boron grooves.

Waste management: impact on metal accumulation and speciation in Aba River channel, Nigeria

Ebong Godwin A.,Etuk Helen S.,Dan Emmanuel U.,Onukwubiri Margaret A. 한국자원공학회 2021 Geosystem engineering Vol.24 No.1

The impact of indiscriminate disposal of waste materials on the quality of Aba River was examined in this research. Levels of Cd, Pb, Cu, Ni, Fe, Zn, Cr, and Mn were determined in water and sediments from Aba River. Modified BCR sequential extraction procedure was employed for the fractionation of metals in sediments. Levels of toxic metals in water (Cd, Pb, Ni, and Cr) were higher than their recommended limits for potable water. However, mean levels of all the metals except Fe were within their safe limits in sediment. Levels of all the metals in sediments were also higher than in water significantly at p < 0.05. Results showed that Cd, Pb, Ni, and Cr existed mostly in the non-residual fractions while essential elements (Cu, Fe, Zn, and Mn) existed mainly in the residual fraction. Consequently, toxic metals were more mobile and bio-available than the essential ones in Aba River. Cd, Pb, and Ni were metals with serious potential health risk to those exposed to the River. Principal component analysis revealed natural and anthropogenic factors as being responsible for the accumulation of metals in the studied Aba River.

압력실의 크기가 수격펌프의 성능에 미치는 영향 평가

( Enongene Ebong George Ngolle ),( Seonggu Hong ) 한국농공학회 2018 한국농공학회 학술대회초록집 Vol.2018 No.-

The Hydraulic Ramp pump has been used to supply water in rural areas without any conventional energy for centuries. The fact that it is self-operating, simple to construct and maintain makes it peculiar in the context of sustainable development. This research is to investigate on the effects of air chamber volume (Va) on the efficiency of a Hydraulic Ram Pump (HRP or Hydram). Specifically, it seeks: To establish a correlation between the air chamber volumes and the efficiency of HRP; to test the appropriate ratio of air Chamber volume (Va) to fall height (Hd); To test the appropriate ratio of air Chamber volume to the lift height (Va/hs); and To see the impact of the angle of supply on the functioning of a HRP. The material used were a reservoir of 50L capacity, an electronic Pressure gauge, a flow meter, and it was constructed using both PVC and Iron pipes of 25mm for the HRP with a supply diameter of 13mm. Data were collected and analysed using Microsoft office Excel (MS Excel). The fall height of 105cm, 170cm and 235cm from the HRP were used against lift heights of 400cm, 500cm and 600cm. Six Air Chambers of 1L to 6L capacities were constructed with same diameter. For each of the volumes sizes, and for each fall height, the 50L water was operated for different lift heights. The maximum pressures were registered and different operating pressures water obtained at complete closure of the delivery valve (0o), when opened at 22.5o, 45o, 67.5o and full open or at 90o turn. The flow rate of pumped water was estimated and waste water was also determined. The main expected results are that; there is effect of the air chamber volume on the efficiency of a HRP. For fall height of 105cm and lift height of 400cm, the 1L Va showed best pumping rate of 5.72 l/s, while the 6L at 6m lift height showed highest water losses. At lift heights of 5m and 6m, the 6L and 3L volumes were best respectively with respective flow rates of 2.39l/s and 2.26l/s. The pressure fluctuation though too high, the maximum was noted for the 1L chamber at 707mbar at the lift height of 7m. The least maximum developed pressure of 666 mbar, was recorded for the 5L at 5m lift height. One can conclude that, the air chamber volume has a significant effect on the efficiency of a HRP and best air chamber volumes for each particular case can be estimated given the fall and lift heights to optimise the cost of production and higher efficiency of a HRP.

HISTORICAL DEVELOPMENT OF HIGH EFFICIENCY BIFACIAL SILICON SOLAR CELLS USING BURIED CONTACT TECHNOLOGY

A. U. Ebong,D. S. Kim,E. C. Cho,Y. H. Cho,I. H. Ji,S. H. Lee 한국태양에너지학회 1996 한국태양에너지학회 학술대회논문집 Vol.- No.-

LOW COST APPROACHES TO SOLAR CELL PROCESSING

A. U. Ebong,D. S. Kim,S. H. Lee,Y. H. Cho,E. C. Cho,Y. S. Min 한국태양에너지학회 1996 한국태양에너지학회 학술대회논문집 Vol.- No.-

Batteries for Photovoltaic Applications

Kim, D.S.,Ebong, A.U.,Lee, S.H. 한국태양에너지학회 1997 한국태양에너지학회 논문집 Vol.17 No.2

Characteristics and properties of batteries applicable to the photovoltaic system are described in this paper. The use of a number of different types of batteries and designs depends on the many and varied requirements for battery power and the different environmental and electrical conditions under which they must operate. Most of the batteries used in PV systems are lead/acid batteries, though nickel/cadmium batteries are used for small applications in locations with extreme climates or where high reliability is essential such as spacecraft. The vanadium redox battery has been acknowledged as a promising energy storage system for a wide range of applications.

Trace Elements in Ground and Packaged Water in Akwa Ibom State, Nigeria

김경웅,Edu Inam,Godwin Ebong,Ubong Eduok 한국자원공학회 2010 Geosystem engineering Vol.13 No.2

About 20 trace elements were measured in 165ground water samples, 8 commercial brands of bottled and sachet water in Akwa Ibom State, Nigeria to ascertain their quality and suitability for drinking purposes. A comparison of the elemental concentrations with World Health Organization (WHO) guidelines and Nigerian Standard for Drinking Water Quality (NSDWQ) showed that with the exception of Al, Cd,Pb, and Fe in some of the ground and packaged water samples,the levels of all the other elements investigated were below the maximum allowable limits. Hierarchical cluster analysis grouped 16 sampling local government councils into four clusters of similar water quality characteristics. Based on the obtained information, it is possible to design a future, optimal sampling strategy for monitoring programs which could reduce the number of sampling stations and associated costs.

실리콘 태양전지의 barrier 접촉 금속의 특성

조은철,김동섭,조영현,지일환,A. U. Ebong,이수홍 한국태양에너지학회 1996 한국태양에너지학회 학술대회논문집 Vol.- No.-

태양광 발전의 최근 업계 동향

이수홍,조은철,김동섭,조영현,민요셉,A. U. Ebong 한국결정성장학회 1997 한국결정성장학회지 Vol.7 No.1

태양전지를 이용한 태양광 발전은 조용하고 안전하게 무한한 에너지원인 태양에너지를 이용하여 전기에너지를 얻는 청정에너지 발생법이다. 1995년 태양전지의 출하량은 약 84.8 MW로, 매년 20% 이상의 시장성장이 예상된다. 본 논문에서는 태양광 발전의 원리, 특징, 종류, 주변기자재 등을 조사하였고, 최신의 태양전지 업계의 동향을 살펴보았다. A solar cell is a device which converts solar energy into electricity without any polluting by-product. Solar cells are useful when they are connected together to form modules. Total production of PV modules worldwide jumped 20 % in 1995 to reach a new record 84.8 MW. In this paper, the recent market trends in photovoltaic industries, principles and characteristics of solar cells and photovoltaic systems are reviewed.