Open Access Short Research Article

Evolution of Hearing Thresholds and the Effect of Age

Isaac Akpor Adjei, Md. Rezaul Karim, Rachid Muleia, Peter Jouck

Current Journal of Applied Science and Technology, Page 1-9
DOI: 10.9734/BJAST/2016/25948

Hearing loss is known to be a worldwide common problem caused by noise, aging, disease, and heredity. The aim of this study was to investigate how hearing thresholds evolve over time and how this evolution depends on age. Hearing thresholds were measured on 226 subjects the at different time-points and were categorized into normal (< 25 dB), mild (25 - 40 dB), moderate (41 - 65 dB) and severe ( 66 dB). A marginal model using Generalized Estimating Equations (GEE) and a generalized linear mixed model (GLMM) were fitted to the data. From both models it was observed that older subjects tend to have more hearing loss. In addition, from GLMM, it was noticed that the rate of decrease in hearing ability is larger for an older subject. This shows that the evolution of hearing loss depend on age at entry into the study. Empirical Bayes estimates were considered in GLMM to make inference about the random effects. It can be concluded that age has an effect on hearing thresholds and on their evolution over time.

Open Access Short Research Article

Analysis of Electrical Substation Installation In a Flood Prone Environment

J. C. Onuegbu, A. E. Anazia, V. N. Agu

Current Journal of Applied Science and Technology, Page 1-9
DOI: 10.9734/BJAST/2016/19379

A generalized analysis of electrical installations in a flood prone city was carried out. Much attention was paid to both security of the equipment and the safety of the personnel. The range of voltage envisaged here was 33/11KV for a non-specific city. The objective was thinned down to a substation located in a city suddenly exposed to flooding due to urbanization and bad environmental sanitation. The study provided a guide on the management of substation in a flood risk zone considering the financial constraint of relocation.  A few managerial measures necessary for the sustenance of such installation were discussed. The result of the study will facilitate availability of power during flooding caused by rain or tidal waves.

Open Access Original Research Article

Use of No-till System on Straw by Cotton Producers in Cameroon

D. Tsozué, P. B. Waga Mana, J. Louléo

Current Journal of Applied Science and Technology, Page 1-11
DOI: 10.9734/BJAST/2016/25509

Field surveys using questionnaires administered among cotton producers semi-openly were done in three cotton zone of Cameroon, Laïndé Massa in the North, Kilwo in the Far North and Tapi in the Adamaoua regions. The objective of this study was to evaluate the degree of appropriation of direct-seeding mulch-based cropping (DMC) systems, identify the problems that influence this appropriation and the consequences of no-appropriation in the cotton zone of Cameroon. The result showed that producers of the study sites were facing several difficulties which impeded the appropriation of DMC systems. These difficulties were landownership issues, financial difficulties resulting in significant financial means necessary for the implementation of DMC systems, the decrease in a radical way of subsidies from the ESA (Eau-Sol-Arbre) project, the difficulty in repayment of loans contracted during agricultural campaigns at the SODECOTON and high land rental costs. The consequences of no-appropriation of DMC systems were the continuous degradation of agricultural soils and decline in soil fertility, due to the acceleration of water and wind erosion, the clean of fields by fire and the practice of inappropriate farming techniques. The model of diffusion of DMC systems in family agriculture proposed by the ESA project cannot be generalized and applied to different contexts and must take in different causes of its no-appropriation identified here for its adoption.

Open Access Original Research Article

An Evaluation of Ecotourism Potentials of Rumkale Archaeological Region

Candan Kus Sahin, Yasemin Kasar

Current Journal of Applied Science and Technology, Page 1-12
DOI: 10.9734/BJAST/2016/25679

In this study, the Rumkale Archaeological Region and its vicinity located in Gaziantep City, Turkey, were examined in terms of potential value for ecotourism activities. The region has high historical reputation and natural beauty which avails magnificent structures for visitors. In examining the ecotourism potential of Rumkale Archaeological Region, a standard questionnaire form was designed and administered to respondents who came on visit to this region. The study revealed that majority of respondents (70%) has heard of Rumkale’s reputation from friends. It also realized that visitors mostly tripped to Rumkale Archaeological Region in order to access the natural beauty and archaeological features. With regard to activity of interest undertaken by visitors to the area, their preferences centered on doing nature walks, trekking/hiking and seeing archaeological residues including historic structures. It also came to the fore that lack of accommodation and difficulties with transportation to the region has negatively affected development of ecotourism activities in this area. Rumkale and its vicinity was scored by visitors according to its suitability for ecotourism activities and in this regard it was revealed that  85% of the respondents ranked this region as suitable for nature walks (trekking/hiking), followed by field photography (73%) and trips to historical and archaeological sites (70%) in that order of importance. After the detailed examination of Rumkale Region and analyzing information from visitors, it is therefore reasonably to conclude and suggest that the Rumkale Archaeological Region and its environs have high potentials for ecotourism and if careful planning is done, these potentials can be tapped for socio-economic development of the area.

Open Access Original Research Article

Development of a Risk Assessment Mathematical Model to Evaluate Invasion Risk of Invasive Alien Species Using Interval Multivariate Linear Regression

H. O. W. Peiris, S. Chakraverty, S. S. N. Perera, S. M. W. Ranwala

Current Journal of Applied Science and Technology, Page 1-11
DOI: 10.9734/BJAST/2016/25901

Evaluation of risk of Invasive Alien Species (IAS) with uncertain and imprcise data is a challenging  task. In the present work, mathematical model for risk assessment is developed by using interval  multiple linear regression analysis in which mimic unceratin and imprecise data. Here both  dependent  and  independent  variables  are  interval-valued.

12 invasive attributes selected as model parameters. Proposed a new method find the solution of design matrix using interval least square method. Here obtained a dataset of 28 invasive plant species which contains single-valued observations of 12 parameters and invasion risk scores which are obtained from National Risk Assessment. Using the dataset formed four interval input datasets. New method is proposed to find the estimates for interval regression coefficient using  interval least suqare method. The interval regression coefficents are estimated using four different  interval  input  data  set. The quality of the approximated model is evaluted by average accuracy  ratio  and  the models are validated using well known six invasive  and  four non  invasive  species.

The approximated model gives average accuracy ratio of 0.730852 along with data set 3 which is the highest among all data sets. Validation results show that the expected risk score of each plant  species  from  National  Risk  Assessment  is within  the  approximated  risk  interval.

Comparing the quality and the validation results, it is found that the approximated model along with data set 3 gives better predictions of risks of invasive alien species if its invasion is dominated by biological traits.

Open Access Original Research Article

Vulnerability of Agricultural Production due to Natural Disaster at Mongla Upazila (Sub District) in Bangladesh

Md. Nuralam Hossain, Md. Mijanur Rahman, Kamrul Islam

Current Journal of Applied Science and Technology, Page 1-13
DOI: 10.9734/BJAST/2016/26007

Mongla upazila (sub district) of Bangladesh has the traditional practice of agriculture but now is extremely vulnerable due to frequent and intensive recurring phenomenon of natural hazards such as salinity intrusion, water logging, flood, cyclone and tidal surges. Therefore, this study was conducted for the assessment of vulnerability and its potential impacts on agricultural productions. This study was also focused to develop a strategy for minimizing the vulnerability. A total of 12 Focus Group Discussion’s (FGD) and 5 Key Informant Interviews (KII) were conducted. A well-organized survey questionnaire was developed and used considering objectives and variables throughout this survey. Primary data was collected by face to face interviews, oral talk with local experts, FGD, KII methods and 3 time field visits. Secondary data was collected from different books, reports, daily newspapers, journal articles, research thesis. The major findings of this study were the causes of severely vulnerability of the production of two main crops that is Aman and Boro and also the agricultural labor. Furthermore, the drinking water was also found as severely vulnerable. This study was also revealed that, 88% respondent opined that the salinity has decreasing agriculture productions due to water logging followed by 4%. In contrast, 81% respondent opined that, the agriculture based occupation is shifting besides; 14% viewed that migration was also increased (climate refugee) due to salinity problem and 79% respondent viewed that, saline tolerant rice (HYV) cultivation is taken as a part of adaptation option. Furthermore, this study also emphasized that, the importance of adaptation of introducing saline tolerant rice varieties; re-excavation of canals, streams, and rivers. Moreover, it is suggested that the negotiation between local leaders and farmers to stop conversion of agriculture based lands into shrimp cultivation lands (gher) may be played as vital role to minimize the vulnerability of sustainable agricultural productions.

Open Access Original Research Article

Diurnal Variation of Midlatitiude Thermospheric Zonal Winds during a Period of Low Solar Activity

William Tafon Sivla, Olakunle Ogunjobi, Virginia Sule

Current Journal of Applied Science and Technology, Page 1-8
DOI: 10.9734/BJAST/2016/26096

The seasonal behaviour of thermospheric zonal winds speeds between geomagnetic latitudes 30-40 degrees north and south from 2006 to 2007 has been studied using zonal wind data recently generated from CHAMP measurements using an iterative algorithm. The period, which falls under the declining phase of the recent solar cycle minimum, is characterized by low magnetic activity and low solar flux levels. Seasons are classified into, June solstice, December solstice, March and September equinoxes. No significant differences are observed between north and south mid-latitude wind variation during the equinox seasons. The switch from westward to eastward direction is observed at about 1500 MLT for all the seasons. Large zonal wind speeds are observed at and after dawn in both hemispheres. The significant difference observed in morning winds at the two mid-latitude bands during the solstices may be attributed to the differences in the solar irradiation.

Open Access Original Research Article

Quantitative Design and Evaluation of EMI Filters in a Digitally Controlled Boost PFC Converter

C. T. Ma, B. H. Yao, F. Y. Chang, K. F. Chen, Y. L. Chen

Current Journal of Applied Science and Technology, Page 1-12
DOI: 10.9734/BJAST/2016/26301

This paper presents a quantitative design procedure for electromagnetic interference (EMI) filters and investigates the effectiveness of the designed EMI filters in a digitally controlled boost power factor correction (PFC) converter. In most modern electrical equipment, the problem of low power factor due to their intrinsic impedance characteristics has greatly reduced the efficiency of using electric energy. In order to improve the quality of electric power supply while achieving the goal of energy conservation, high-power converters tend to use an active PFC circuit as their front stage connecting to the mains. However, active PFC circuits which utilize high-frequency switching techniques in tracking input line currents often bring EMI and harmonic distortion problems to distribution systems. To ensure that the equipment can meet the relevant EMI standards, some properly designed EMI filters must be used to reduce the common mode and differential mode noises. Due to inevitable nonlinear interactions of the EMI filter and the PFC bridge rectifier, the EMI filter is normally designed by repeated trial-and-errors in practice. To improve the design efficiency, this paper firstly introduces a single-switch boost PFC circuit widely used in various ac-dc converters along with the proposed systematic design procedure for EMI filters and followed by simulation analysis in PSIM software environment. Finally, a 1 kW digitally controlled boost PFC converter prototype with the designed EMI filter is practically constructed and tested to verify the effectiveness of the proposed design method.

Open Access Original Research Article

The Effects of Weight Changes on Ship’s Stability

Robert Poku, Tokoni W. Oyinki, Charles A. N. Johnson, Ezenwa A. Ogbonnaya

Current Journal of Applied Science and Technology, Page 1-9
DOI: 10.9734/BJAST/2016/25704

Over the years, there had been increase in the use of offshore structures. This might not be unconnected with the awareness of the importance of the maritime sector as well as the rise in energy demand. Consequently, the construction, transportation of offshore structures has drastically increased. The loading of offshore structures such as barges requires thorough and careful planning so as to ensure that the barge is stable. This is achieved where following the loading and offloading of the vessel, the position of the centre of gravity, trim and heel are always in acceptable level. This research therefore, employed a rectangular barge on which ballasting procedures were carried out aimed at eliminating trim and heel. This is done by pumping into the barge 1802.84 tonnes of water which was distributed to tanks 2S and 4S. At the end trim and heel are taken to be corrected when LCG = 33.53 m and TCG = 0 where the reference point was the body system orientation (taken from the bow). However, owing to the little quantity of water to be distributed compared to the size of the given tanks, the result showed that trim and heel are taken to be corrected when XCG (LCG) = 28.49 m and YCG (TCG) = 0.12 m.

Open Access Original Research Article

Usage of Multidimensional Scaling Technique for Evaluating Performances of Multivariate Normality Tests

Soner Yiğit, Mehmet Mendeş

Current Journal of Applied Science and Technology, Page 1-8
DOI: 10.9734/BJAST/2016/26256

This simulation study has been conducted to evaluate the performances of six different multivariate normality tests under different experimental conditions. Obtained results of 50,000 Monte Carlo Simulation showed the most reliable when the Royston (Roy), Srivastava-Hui (S-H), and Doornik-Hansen test (D-H) have been applied. The above mentioned tests retained Type I error rates at nominal alpha level (0.05). Whereas, the estimations of Type I error of Mardia’s Skewness (M-S), Mardia’s Kent (M-K) and Henze and Zirkler (H-Z) test caused variations depending on sample size and number of variables. The estimations of test power of all tests have been affected by distribution shape, and the all related tests produced highly test power values especially when samples were taken from Multivariate Cauchy and Lognormal distributions. On the other hand, the estimations of test power of all tests have been found extremely low when samples were taken from multivariate t-distribution with 10 d.f. Multidimensional Scaling (MDS) technique has been applied to classify the tests those have had similar performance and the factors those affected the performances of the above mentioned tests. At the end of Multidimensional Scaling analyses, it has been observed that the Roy, S-H and D-H tests showed similar performance, and the performances of these tests were obviously different than that of the others in general.