Abstract: 

Experimental investigation has been performed in this work to evaluate the performance of effect of fluid velocity on the performance and heat transfer rate of double pipe heat exchanger. Experimental work included designing and manufacturing of shaped double pipe heat exchanger. The inner tube is inserted inside the Perspex tube. the internal tube made from copper with length (2200mm) where (200mm) was left at the entrance and exit heat exchanger regions and adding thermal paste around the copper tube which has thickness (3 mm) and adding eight thermocouples  that are fixed on the inlet and outlet of the tube and shell and the other four fixed on the outer surface of the inner tube. The shell has a (2000mm) length, (100mm) internal diameter, and (5mm) thickness. The cold and hot water was used as a working fluid in the shell and tube side, respectively. The flow rate at the shell kept constant while changed at the tube. Cold water varied at volume flow rates (2, 4, 6, 8 L/min) through annuli and Reynold’s number of the hot water ranged from (6295.93 to 25159.02) through the inner tube and Reynolds number of the cold water ranged from (569.11 to 2275.93). Experimental results showed that when Reynolds number increase with increasing the water flow rate due to the water flowing increment in the shell and tube sides for straight tube also increase with heat transfer when increase the water flow rates.

Keywords:  Heat exchanger; Counter flow, Double pipe heat exchanger (DPHE), fluid velocity.

Abstract: 

This work investigated experimentally the temperature distribution in double pipe heat exchanger. A Copper tube with a Perspex shell was used to manufacture a double pipe heat exchanger. The rig of the experimental test section confirms a horizontal heat exchanger which consist of Copper tube (2200mm) where (200mm) was left at entrance and exit heat exchanger regions to confirm a steady water flow inside the test section. The test section was insulated by glass wool (3 mm) which prevent losing heat to the surrounding and adding thermal paste around the copper tube which has thickness (3 mm). The shell dimensions were (2000mm) length, (100mm) internal diameter and (5mm) thickness. Both ends closed by four Perspex flanges to close the ends of the annular side. Where water is used as working fluid. Cold water and hot water were used as working fluids in the shell side and tube side, respectively. In this experiment eight K- type thermocouples were used in the test section to measure the temperature distribution through the test section. Where four thermocouples were distributed by equal distance along the outer surface of the inner copper tube 20 cm from the inlet of the inner tube and (40 cm) for each other thermocouples. Four thermocouples were fixed in the inlet and outlet of shell and tube, respectively to measure the inlet and exit temperature of the hot and cold water. Temperature distribution and the rate of fluid temperature change through a double pipe heat exchanger was investigated experimentally. This study will help to design a suitable heat exchanger length depending on the value of temperature change along the studied heat exchanger.

Keywords:   Heat exchanger; Counter flow, Double pipe heat exchanger (DPHE); temperature distribution.

Abstract: 

The study aimed at revealing the role of the school administration in enhancing the teachers’ communication skills in the schools of the Directorate of Education in the Ramtha District. The researcher used the descriptive correlation survey approach. The study sample comprised of (465) male and female teachers. The questionnaire was used as a study tool. The results showed that: The role of the school administration in enhancing teachers’ communication skills in the Ramtha district schools from the respondents' viewpoint was a (high) degree, and that there were no differences attributable to the effect of the variables: (gender and academic qualification). Where there were significant differences attributed to the impact of the years of experience variable and came in favor of the category “10 years or more.” The study recommended reinforcing the administration's role in holding training courses for the school staff on using information technology especially the distance learning, that has become the most effective method nowadays since it can be considered an education stock in case of any matter that may hinder the continuity of education.

Keywords:  school administration ;  communication skills.

Abstract: 

This paper proposed a model between the watermark and encryption makes it has the ability to know the ownership of the digital signal and maintaining the data must biometric safe. Arnold transformation turned to encrypt digital data and uses a separate waves shift to insert a watermark in the image is used. Results of experimental sensory perception of transparency refers to good efficiency for transparency and the value of the ratio of signal to noise up to more than 70 decibels for photos.

Keywords:  Watermarking; Fingerprint; MSE; PSNR; Encryption; DCT; DWT

Abstract: 

This study focuses on the link between credit risk and bank performance in Nigeria. It investigated the effect of non-performing loans on the performance of deposit money banks in Nigeria. The study also evaluated the effect of loans and advances on the performance of deposit money banks in Nigeria and determined the relationship between loan loss provisions and the performance of deposit money banks in Nigeria. It equally examined the effect of equity/shareholders’ fund on the performance of deposit money banks in Nigeria. The study used panel research design and panel data from 2009 to 2018 obtained from bank annual reports of the sampled banks was used for the empirical analysis. Thereafter, panel econometric techniques were used to estimate the effect of credit risk on bank performance in Nigeria. The study discovered that a percentage change in Equity or Shareholders’ fund increase profitability (ROA) by about 19%. It was also revealed that a percentage change in loan to deposit ratio reduces profitability by 3% while a percentage change in Non-Performing loan increases profitability by 7%. The study therefore recommends that Banks in Nigeria should monitor their loans and advances and avoid mismatch between its assets and liabilities to safeguard their banks from poor CAMEL rating and bank failure. In addition, banks should continue to monitor its capital base and maintain the minimum capital to risk weighted assets to avoid crisis. Finally, future studies should examine managerial differences, geographical factors, bank classification and whether size have significant impacts on credit risk and bank performance.

Keywords:   credit risk; bank performance, panel analysis, Nigeria.

Abstract: 

Nigeria is one of the underdeveloped countries in Africa with a very low economic growth and low standard of living. One of the major contributors to this poor situation is the terrible state of the electric power supply. More than 76% of homes, industries and businesses experience irregular electricity supply. Nigeria’s electricity production and supply are characterised by obsolete structures and systems that cannot meet the present domestic and industrial demands. Fossil fuel such as crude oil and coal are the greater sources of electricity for the nation and they are the leading causes of climate change and the release of GHGs.

This research paper focuses on the potential of micro-hydropower plant in Nigeria as potential source of electricity, due to the numerous high-speed rivers, lakes and canals in the country whose mechanical power can be harness to provide off-grid power to remote areas and also to the areas that are still outside the main grid network. This paper further reflects on the current energy situation in Nigeria, the need to explore green energy such as solar, micro-hydropower etc which can help overcome the current power crisis, and can play an important role in the economic development and progress of the country. The existing potential sites are mentioned and the means to identify new sites are outlined by performing hydrology studies, topographic studies, water head calculations, turbine selection, and so forth.

Keywords: Megawatt, Potentials, Energy, Hydroelectric, Sustainable.

Abstract: 

Nigeria is one of the underdeveloped countries in Africa with a very low economic growth and low standard of living. One of the major contributors to this poor situation is the terrible state of the electric power supply. More than 76% of homes, industries and businesses experience irregular electricity supply. Nigeria’s electricity production and supply are characterised by obsolete structures and systems that cannot meet the present domestic and industrial demands. Fossil fuel such as crude oil and coal are the greater sources of electricity for the nation and they are the leading causes of climate change and the release of GHGs.

This research paper focuses on the potential of micro-hydropower plant in Nigeria as potential source of electricity, due to the numerous high-speed rivers, lakes and canals in the country whose mechanical power can be harness to provide off-grid power to remote areas and also to the areas that are still outside the main grid network. This paper further reflects on the current energy situation in Nigeria, the need to explore green energy such as solar, micro-hydropower etc which can help overcome the current power crisis, and can play an important role in the economic development and progress of the country. The existing potential sites are mentioned and the means to identify new sites are outlined by performing hydrology studies, topographic studies, water head calculations, turbine selection, and so forth.

Keywords: Megawatt, Potentials, Energy, Hydroelectric, Sustainable.