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Electrocatalytic Reduction of Oxygen at Poly (4-Amino-3-Hydroxynaphtalene Sulfonic Acid)/Reduced Graphene Oxide Composite
No full textThe rapid growth of the global population and industrial activities pose a great challenge to
meeting ever-increasing energy demands. This thesis adapts a modified synthesis of graphene
oxide (GO), an important starting material in graphene chemistry, convert graphene oxide back
to graphene-like structure, and finally shows the electrochemical behavior poly (4-amino-3-
hydroxynaphtalene sulfonic acid)/rGO composite and also demonstrates its possible application
in electrocatalytic reduction of oxygen. In this work, the electrochemical, XRD, and FTIR
analysis gave evidence for the formation of graphene oxide (GO) from graphite and the reduced
graphene oxide (rGO) from GO. The electrocatalytic activity of the poly (4-amino-3-
hydroxynaphtalene sulfonic acid)/rGO composite modified electrodes towards oxygen reduction
reaction were studied. The p-(AHNSA) modified glassy carbon electrode shows a two-electron
reduction of oxygen to hydrogen peroxide and the p-(AHNSA)/rGO modified glassy carbon
electrode shows a direct four-electron reduction of oxygen to water. Koutecky-Levich plot
analysis was used to predict the mechanism and evaluate the kinetic parameters
Aquifer Characterization of Assosa Area, Benishangul-Gumuz Regional State, Western Ethiopia
No full textThis study assessed in Assosa catchment of Benishangul Gumuz Regional State, Western
Ethiopia which is aimed to characterize Assosa Town ground water systems with the help of
different methods and approaches that includes desk review of hydrogeological and geological
map of the region, pumping test data and the collected data has been analyzed with the help of
different software applications like Aquifer test 2011.1, ArcGIS 10.1, Global Mapper16,
Surfer10, Strater Demo 4 and Microsoft Excel. The study area comprises different rock units like
basalt, basement outcrops, and quaternary sediments; and geological structures which was the
reason for the formation of different landforms, primary and secondary permeability with
porosity that contributes significant role on the aquifer properties. Aquifers developed in the area
is due to secondary processes and in similar fashion, degree of variations in the groundwater
productivity is mainly linked with extent of differences in the effect of these processes in the
rocks. Hydrodynamic analyses of the catchment aquifers reveal that, hydraulic conductivity is
ranged from 0.0677 to 1.544 m/d with a mean value of 0.59 m/d and for that of transmisivity it
ranged from 2.76 to 44.3 m2/d with a mean value of 18.993 m2/d; from these hydraulic
parameters and geomorphologic set up and geologic units of the area, the determined potentiality
degree of the catchment aquifer is classified as moderately productive fissured aquifer, low
productive fissured aquifer and aquitards/ aquicludes. Generally, the study area is mostly covered
by crystalline basement rocks (hard rocks) which is regionally known to be called aquicludes;
therefore, site selection for ground water investigation needs a very care full attentions due to
less existence of secondary structures that enables ground water formatio
Trends, Levels and Determinants of Under Nutrition among Women of Reproductive Age in Ethiopia
No full textGood nutrition lays the foundation for healthy, flourishing and productive nations. The low nutritional status among women is attributed to different factors. The rate of under nutrition persist in low income countries in which Sub-Saharan Africa took the leading part. In Ethiopia the prevalence of under nutrition among women of reproductive age was higher than reported for Sub Saharan Africa. The aim of this study is therefore to examine the trends, levels, differentials and demographic and socio-economic determinants of under nutrition among non pregnant and non- lactating women of reproductive age (15-49) in Ethiopia. This study was carried out using quantitative data from 2000, 2005 and 2011 nationally representative Ethiopian Demographic and Health Surveys. The dependent variable was women’s nutritional status measured in terms of body mass index and coded in binary out comes. Those women with BMI value less than 18.5 were considered to be at risk of under nutrition. Logistic regression models were employed to identify the determinant factors of women under nutrition. Qualitative data were also collected to supplement and interpret the results of quantitative analysis. Underweight in Ethiopia has shown a declining trend from 30.1% in 2000 to 26.9% in 2011. Specifically the prevalence of under nutrition has declined by 10.6% in about one and half decades. Age (young and old), marital status (never married), religion(Muslim), place of residence (rural), region and proxies for low socio economic status (i.e. poor wealth, unimproved source of drinking water and toilet facility) were found to be significantly correlated with being under weighted. The possible areas for the risk of women under nutrition in Ethiopia were vividly distinguished. Thus the policies that target these distinct areas have to be employed with specified programs and strategie
On the Generators of Codes of Ideals of the Polynomial Ring for Error Control
No full textShannon introduced error detection and correction codes to address the growing need of
efficiency and reliability of code vectors. Ideals in algebraic number system have mainly
been used to preserve the notion of unique factorization in rings of algebraic integers and
to prove Fermat’s Last Theorem. Generators of codes of ideals of polynomial rings have
not been fully characterized. Ideals in Noetherian rings are closed in polynomial addition
and multiplication. This property has been used to characterize cyclic codes. This class of
cyclic codes has a rich algebraic structure which is a valuable tool in coding design. The
Golay Field which has been used to generate codes over the years provides codes of fixed
length which do not reach Shannon’s limit. This research has used Shannon’s proposed
model to determine generators of codes of ideals of the polynomial ring to be used for
error control. It presents generators of codes of ideals of the polynomial ring associated
with the codewords of a cyclic code C. If the set of generator polynomials corresponding
to codewords is given by I(C) (a set of principal ideals of the polynomial ring), it has
been shown that I(C) is a cyclic code. Additionally the suitability of codes of ideals of
the polynomial ring for error control has been established. Application of Shannon’s Theorem on optimal codes has been done to characterize generators of codes of ideals of the
polynomial ring for error control. The generators of codes of the candidate polynomial
ring F2n [x]/hxn −1i have been investigated and characterized using lattices, simplex Hamming codes and isometries. The results of this research contribute significantly towards
characterization of generators of codes from ideals of polynomial rings
Excluded Volume Effects on the Conformation of Semi-Flexible 2D Ring Polymers
No full textIn this paper we investigate the excluded volume effect on the structural and conformational
properties of 2D ring polymer chains using lattice Monte Carlo simulation. In order to take into
account chain volume exclusion and crossing of bonds, the bond fluctuation algorithm(BFA) was
implemented. Monomer chain flexibility was taken into account by producing chain bending
rigidity ks. Chain properties were studied by varying chain size N and the bending rigidity
ks. We have computed key chains physical quantities such as the radius of gyration Rg and
persistence length lp
Laser Trapping Ionization of Human Red Blood Cells with Four Hemoglobin Types: A Preliminary Study of Hemoglobin Quantitation
No full textIn this work, a high intensity gradient laser was used to study the threshold ionization energy,
the threshold radiation dose, and the charge (to determine hemoglobin quantitation) of four
different samples of hemoglobin type. The study was conducted using AS, AC, FA or AF, and
FSC hemoglobin types were obtained from MSCC at the MMC. The experiment was performed
for each cell, for a total of 62 cells for Hb AS, Hb FA, and Hb FSC, and 47 cells for Hb AC,
were trapped and ionized by a high intensity infrared laser at 1064 nm. With the laser trap
serving as a radiation source, the cell underwent dielectric breakdown of the membrane. When
this process occurs, the cell becomes highly charged and its dielectric susceptibility changes.
The charge creates an increasing electrostatic force while the changing dielectric susceptibility
diminishes the strength of the trapping force. Consequently, at some instant of time the cell
gets ejected from the trap. The time inside the trap (ionization time) while the cell is being
ionized is used to determine the threshold ionization energy and threshold radiation dose, and
the intensity of radiation and the post ionization trajectory of the cells are used to determine the
the charge for each cell of four different samples of hemoglobin type using NonlinearModelFit in
Mathematica. Laser tapping technique is indeeded promissing for a very precise measurement
of the hemoglobin types present in a blood sample. Knowing the hemodlobin type present in a
blood sample is essential in screening sickle cell diseases and will vastly improve the accuracy of
monitoring a sickle cell anemia patients receiving various types of treatments
The Effect of Nonfinancial Rewards on Employee Retention the Case of United Bank S.C.
No full textIn this research the effect of nonfinancial reward on employee retention were empirically examined at United Bank. Both primary and secondary data were used for analysis. Primary data were collected through questionnaire from 318 respondents selected using random sampling technique from the target population size of 1, 551 where as secondary data were obtained using document review. Data obtained was analyzed using Statistical Package for Social Sciences. Descriptive and inferential statistics methods were used while analyzing data. Thus, the result of correlation analysis evidenced recognition, career advancement opportunity and training & development had positive and moderate relationship with employee retention. The beta coefficient value in multiple regressions also revealed nonfinancial rewards studied had a positive influence in bringing variation in employee retention. The finding of descriptive analysis also revealed that the respondents average agreement on recognition, career advancement and training & development rewards were moderate level. This implies the practice of these rewards at United Bank were unsatisfactory to retain its employees. Therefore, the management shall work on recognition, career advancement opportunity and training & development reward practices to enhance the retention of employees
Risky Sexual Behaviours among Night School Students in Arada Sub-City
No full textBackground: Risky sexual behaviors are any behavior that increases the probability of adverse
sexual and reproductive health. Adolescent and young aged 15–24 years are at particularly high
risky sexual behaviors. Risky sexual behaviors predispose adolescent and young people to a
variety of sexually associated problems.
Objectives: The objective of the study is to assess the magnitude of risky sexual behaviors and
its associated factors among night school students in Arada sub-city 2017.
Methods: A cross-sectional quantitative study design method complemented with qualitative
method carried out among night school students in Arada Sub-City, Addis Ababa, Ethiopia. Five
hundred forty individuals were selected from a total of 3,641 by multi- stage sampling method.
The data were collected by using pre-tested structured self-administered questionnaire. Data
were entered into Epi-Info version 7 and analyzed using SPSS version 24 software.
Result: A total of 540 night school students were enrolled in the study with response rate of 514
(95.2%) among those 317(61.7%) of the study participants were females; 342(66.5%) the study
participants had sexual experience and only 78 were married. Among the sexually active students
139(40.4%) reported that they had two or more sexual partners in their lifetime, 127 (37.1%)
reported sexual contact with casual person, 26(7.6%) with commercial sex workers and 222
(64.9%) had risky sexual behavior. Multivariable logistic regression analyses showed that males
are 1.676 times more likely to have risky sexual behaviors than females [AOR= 1.676 (95% CI:
1.026-2.741)] and being in 15-19 age group 0.593 times less likely to have risky sexual
behaviors than 20-24 years [AOR= 0.593 (95% CI: 0.363- 0.739)]. Similarly being single and
divorced participants were 3.326(1.737-6.368) and 3.939(2.043-7.595) with 95% CI times higher
risky behaviors respectively. Practicing sex after drinking alcohol were [AOR = 4.858 (95% CI:
2.314-10.196)] and sex after watching pornography were [AOR = 3.964 (95% CI: 1.559-
10.078)] associated with risk sexual behaviors.
Conclusion: Significant number of night school students had two or more sexual partners and
sex with sex workers had risky sexual behavior that might predispose them to different sexual
and reproductive health problems. Reducing risky sexual behavior among night school students
can be achieved through multi-sectored responses in the school
Mother- to-Child Transmission of HIV Infection and Its Associated Factor among Exposed Infants on Care and Follow-Up in Selected Health Centers, Addis Ababa Ethiopia, 2017
No full textBack ground: Mother to child transmission of HIV is responsible for about 20% of all HIV
transmissions of which 95% are found in the Sub-Saharan Africa. Without any intervention,
MTCT of HIV among non-breastfeeding infants’ ranges from 14-32% in developed nations to
25- 48% in resource limited populations. Prevention of mother-to-child HIV transmission
(PMTCT) is still the most effective intervention in fighting new HIV infections.
Objective: To assess the transmission rate and the associated factors of Mother-to-Child
Transmission of HIV Infection among Exposed Infants on Care and Follow-Up in selected health
centers of Addis Ababa, Ethiopia, 2017
Methods and Materials: A facility based retrospective study was conducted on HIV exposed
infants who were on care and follow up from September 2012 to August 2016 enrolled in 10
selected health centers from Lideta, Arada and NifasSilkeLafto Sub Cities. The study was
conducted from January to June 2017 by revising records of HIV positive mothers’ and their
HIV exposed infants’ at PMTCT clinics of the 10 selected health centers. For this study the
sample size was 228; the study subjects were selected using simple random sampling method.
Results: Of the 228 infants 5 (2.2%) were found HIV positive during follow up. Two hundred
twenty (96.5%) had exclusive breastfeeding, whereas 8 (3.5 %) of the study subjects had
exclusive replaced formula feeding. ART prophylaxis was given to 225 (98.7 %) of the exposed
infants, only 2 (0.9%) haven’t received ART prophylaxis. Initiation time of ART for the mother
was significantly associated with the HIV status of exposed infants {AOR=0.32, 95%CI (0.015-
0.74)}.
Conclusion and Recommendation: The study revealed that very low prevalence of mother to
child transmission of HIV. There is a need to maintain current implementation of prevention of
mother to child transmission program to help ensure that continually maintain low MTCT of
HIV prevalence
Supply Chain Integration to Enhance the Performance of Ethiopian Footwear Industry
No full textThe footwear industry in Ethiopia is considered as an important sub-sector that leads the whole leather
sector modernization and that can contribute highly for the development of the country. Although the
export of leather footwear started in 2005, its value has been growing steadily since then and is expected
to make a big impact on the Ethiopian economy. In addition to the economic impact that result from the
trade, the job opportunities that the industry can make a significant impact on poverty reduction.
The major problems contributing for the poor performance of this industry are mismanagement of the
flows of product/material, information and financial flows of a supply chain and lack of integration on the
supply, internal and customer side. The main objective of this study is to improve the performance of the
Ethiopian Footwear through supply chain integration.
In order to show where the focus area of the supply chain integration for the Ethiopian footwear sector
should be, this study used a correlation analysis. In order to undertake this research, 4 footwear factories
(Anbessa, Peacock, Ramsay and Huajian) were considered and 16 questionnaires were distributed to
these 4 footwear industries’ Production /purchasing/marketing and finance managers. Primary data was
collected with the help of questionnaires and personal interviews. Additionally, secondary data were also
gathered using previous research works in the sector and different documents.
The collected data have been summarized using descriptive analysis method and analyzed by a statistical
tool called histogram. Furthermore, Spearman’s correlation coefficient was used to determine the
strength of relationships between the variables (supply integration, customer integration, internal
integration and performance or Product quality & Competitiveness). Based on the identified key factors
and the collected data, the level of supply chain integration in Ethiopian Footwear Industry was assessed
and problems were identified. Finally the research came up with the following findings: internal, supplier,
customer and integration are positively and strongly correlated with footwear factories performance
(product quality and competitiveness). This shows that the focus should be in all areas of supply chain
integration areas. At the end a model is developed which gives a solution to the current supply chain
integration problems of the Ethiopian footwear Industry