Table of Contents

Frequency and Duration Method Reliability Analysis: Case Study of Bama and University 33kv Distribution Feeder Maiduguri

Kalli, B. M , Modu M Tijjani, Sadiq A. Goni,  Babagana M. Digol, Hajja I. Usman &

Tijjani, B. N                                                                                                                              1-17

Graphical Passwords and Methods for Enhanced Password Memorability 

Obasan  Adebola, Abdulazeez Sikiru,Patrick Owohunwa                                                       18-38

Incessant and Unreliable Power Supply in Nigeria: Causes, Effects and Solutions (Ikorodu, Lagos State, Nigeria as a Case Study)

Oshin, Ola Austin                                                                                                                    39-62

Effect of Curing Delay on the Compressive Strength of Concrete

Nura Hassan, Jibrin Umar, Mohammed Ya’u, & Hussaini Ausaja Amshi                                63-78

EFFECT OF CURING DELAY ON THE COMPRESSIVE STRENGTH OF CONCRETE Nura Hassan, Jibrin Umar, Mohammed Ya’u, & Hussaini Ausaja Amshi Department of Civil Engineering Technology, Federal Polytechnic Damaturu Email: Nura2108@yahoo.co.uk

Abstract

Curing is very vital in the production of strong and durable concrete. This research work investigates the effect of curing delay on the compressive strength of concrete. Mix ratios of 1:1.5:3 and 1:2:4 were prepared with two different water/cement ratios, that is, water/cement ratios of 0.5 and 0.6. A total of 240 cubes were cast, that is, 60 cubes each of 1:1.5:3 with water cement ratio of 0.5 and 0.6, and 1:2:4 with water cement ratio of 0.5 and 0.6. Curing ages of 7, 14, 21, and 28 days were used. However, curing delays of 0, 1, 2, 3, and 4 days were used in this piece of work, where zero curing delay is serving as the control. The work was carried out under very dry environmental condition with relative humidity ranging from 10 – 15%. The results showed that, compressive strength of concrete decrease with the increase in the duration of curing delay, but the effect reduce with the increase in curing period. However, the curing delays result to  irreversible loss of compressive strength of the concrete. The richer mixes have more resistance to loss of strength compared to lean mixes. The lower the water/cement ratio, the higher the resistance to loss in compressive strength caused by curing delay. It is therefore, recommended that concrete should be properly cured without delay to avoid loss of strength.

INCESSANT AND UNRELIABLE POWER SUPPLY IN NIGERIA: CAUSES, EFFECTS AND SOLUTIONS (IKORODU, LAGOS STATE, NIGERIA AS A CASE STUDY)

Oshin, Ola Austin

Elizade University, Ekiti State

Email: austin.oshin@elizadeuniversity.edu.ng, zolaolaaustin@yahoo.com

Abstract

The present unreliable and erratic power supply is a pointer to the fact that there is a great need for fault evaluation and reliability studies of electric power system in the Nigeria. The recent blackout in the country has grounded many activities and has destroyed many industrial processes. Also, the power industries face a lot of problems. Some of the highest priority issues being generation of sufficient power, urgent clearance of faults, adequate protection and increase reliability of the system,  that is, bringing a steady uninterrupted power supply to the consumers. The Nigerian power problem resulted to incessant planned, forced and unplanned outages. In addition, it has resulted to erratic and unreliable supply of electricity in the country. It has reduced productivity and has increased unemployment rate in the country to over 40million (this figure is over 70% of Nigerian youths. It has led many of the youths in the country to crime. It has led many of the deaths of many innocent people in the country.  Hence, an analytical method is developed to assess the dynamic- reliability of the distribution system, as well as optimizes the occurrence of faults along each of the individual consumer point in a feeder in order to improve the performance of the system. This research publication therefore evaluates the occurrence of faults which is about 856 occurrences during a period of 8 years and outages which range between 1118 to 3785 hours per annum along the distribution lines, also the failure rates of each of the feeders were analyzed in order to improve on the supply of electricity in the distribution network. The reliability of the system which ranges between 8.57*10^-12to 9.548*10^-5 were analyzed; and fault clearing techniques were carried out. Efforts were made to adequately assess the failure rates of the feeders which range between 0.003 and 0.001 and reliability of the distribution system. Efforts were also made to improve the performance of the system. As a result, it was possible to establish improvement techniques which ensure adequate and constant supply of electricity to all the consumers for industrial growth and employment: a basic solution to increasing crime rate in the country.

GRAPHICAL PASSWORDS AND METHODS FOR ENHANCED PASSWORD MEMORABILITY

Obasan  Adebola¹, Abdulazeez Sikiru²,Patrick Owohunwa³

¹ Department of Computer Science, Kaduna Polytechnic,

^2&3 Department Mathematics, and Statistics, Kaduna, Kaduna State, Nigeria.

Email:  aolukay@yahoo.com, ysabdul94@yahoo.com, owohunwapatrick@yahoo.com

Abstract

Corporate organizations are depending on Internet-enabled Information Technology to reach their target users is a common practice today. This development has made huge users to employ the same technology to satisfy their diverse needs. Consequently, computer and information security has  become  a critical from  service provider viewpoint  to  achieve  protection, confidentiality, integrity, and ensure  reliable  access  to  information resource when  using  computer systems.  To achieve this, text-based password authentication has  been widely used without  flawlessness because remembering  secure  password chosen   from  mixture of  random  alphanumeric  and  non-alphanumeric   characters  is  an  everyday  problem  for  all  users because  of  individual memory  limitation. Graphical     password which  works  just  by  clicking  with  a  mouse  or  stylus  could  be  used for  user authentication. In this paper, we highlight needs for study of password, how memory influences passwords, different methods for improving memorability of passwords and memorability to achieve the main objective of the study.  Which is to design a graphical authentication system that uses three autobiographical events background images in draw-grid environment to reduce memory loads of password and to ultimately achieve better memorability and security of passwords. We also highlight memorability and  security features of  the proposed scheme.

FREQUENCY AND DURATION METHOD RELIABILITY ANALYSIS: CASE STUDY OF BAMA AND UNIVERSITY 33KV DISTRIBUTION FEEDER MAIDUGURI

Kalli, B. M ¹, Modu M Tijjani², Sadiq A. Goni^3, Babagana M. Digol⁴, Hajja I. Usman⁵ and Tijjani, B. N⁶

Department of Electrical/Electronic Engineering,

Ramat polytechnic Maiduguri, Nigeria.

Email: kallibmai@gmail.com

Abstract

Failures in distribution systems not only reduce reliability of power system but also have significant effects on power quality since one of the important components of any system quality is reliability of that system. To enhance utility reliability, failure analysis and its frequency must be studied. This paper describes a case study of the reliability of 33Kv distribution feeders (Bama and University) .The information obtained from Transmission Company of Nigeria along Baga Road. Reliability indices such as the MTBF and MTTR are determined, analytically, by using outage information gathered from the Transmission Company. The study generally shows that the distribution feeders have not been adequately maintained leading to frequent and delayed forced outage indicating unreliable performance of the individual units and the entire station.