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Thermo-Mechanical Analysis of Aluminium Silicon Carbide Composite Materials
No full textIn recent years, composite materials have dominated the electronics
industries and other manufacturing industries. Hence, composite
materials like aluminium silicon carbide (AlSiC), has been employed to
produce heat sinks, which are used mainly to manage heat in electronic
devices. However, thermal fatigue of such composite material is a major
challenge in maintaining reliability of the device. This paper
investigates the thermomechanical effect of AlSiC composite materials.
Finite element method (FEM) was used in the analyses of the composite
materials based on the particulate inclusions between 10 \u2013 50%
compositions. The thermal profile (-40oC to 85oC) employed in this
study is used commercially for consumer products. The fatigue life of
the composite material which is based on the stresses and strains
parameters were obtained and evaluated. The results from this
investigation suggests that the deformations, strains, and stresses
reduced with increase in the percentage of particulate inclusions.
Also, the fatigue life of the composite material showed that the
reliability of the material is increased with higher inclusions. This
investigation demonstrated that 50% particulate inclusions has a better
number of cycles to fatigue failure (5.09E+04) when compare to other
inclusions. While 10% inclusions has the least fatigue life (4.39E+04)
based on this investigation
Chickenpox Vaccination: Knowledge and Attitude of Child-Bearing Women of Abraka, Delta State, Nigeria
Get PDFChickenpox is a common childhood disease which is highly contagious.
The World Health Organization (WHO) recommends that in countries where
chickenpox is an important public health burden, chickenpox vaccination
should be introduced into their routine immunization programs. This
present study is to ascertain the level of knowledge and attitude
towards chickenpox infection and its vaccination among child-bearing
women in Abraka, Delta State, Nigeria. A cross-sectional descriptive
study design was adopted to assess the knowledge and attitude towards
chickenpox vaccination among 140 randomly selected child-bearing
mothers residing in Abraka community. Of the 140 respondents, a greater
number was within 30-40 years of age (61.4%). Most of the respondents
(95.7%) had heard about chickenpox and 77.1% stated correctly its mode
of transmitted. Majority were well aware of the signs and symptoms of
the infection which included itching rashes (85.7%), blisters and red
spots (66.4%), and fever (61.4%). Despite the fact that most of the
respondents (72.9%) knew about chickenpox vaccination, only very few
(19.3%) claimed to know the vaccine used, with less than half of the
respondents (44.3%) correctly indicating two doses as the complete
dosing for chickenpox vaccination. A greater proportion (91.4%) of the
women had vaccinated their children against chickenpox, and believed
that it was effective (82.1%). A high level of knowledge and positive
attitude towards chickenpox vaccination among child-bearing women was
evident in this study, however, it is paramount to encourage pregnant
women and mothers attending antenatal care to immunize their children
against vaccine-preventable diseases (VPDs)
Effects of Phosphorous Application on Growth Performance, Yield and Nutritional Value of Cockscomb ( Celosia argentea L)
Get PDFEffects of phosphorous (P) level on performance, yield and nutritional
value of Celosia argentea L. were evaluated with the aim of determining
the P level that supports the best growth, yield and nutritional
qualities of the crop. The levels of P were: normal (1.348 mg\ub7kg-1
of P/pot, NP), medium (6.743 mg\ub7kg-1 of P/pot, MP), high (13.48
mg\ub7kg-1 of P/pot, HP) and no P application (control, CP). The crop
growth rate (CGR) increased with increase in phosphorus gradients (NP =
0.05 g/m2\ub7d-1, MP = 0.09 g/m2\ub7d-1 and HP = 0.12
g/m2\ub7d-1). High and medium P rates increased the relative growth
rate (RGR), HP had the highest RGR (0.05 g\ub7g-1/day) followed by MP
(0.04 g\ub7g-1/day). Addition of P increased leaf area (LA) of C.
argentea. Crude protein of the control was higher (5.56%) compared to
the other P treatments (NP = 5.14, MP = 5.11 and HP = 5.03%).
Phosphorus applications were beneficial for growth and enhancement of
nutritional quality of C. argentea. NP and MP are recommended for
growing this vegetable crop
Biodegradation Studies of Benzene, Toluene, Ethylbenzene and Xylene (BTEX) Compounds by Gliocladium sp. and Aspergillus terreus
Get PDFBenzene, toluene, ethylbenzene and xylene (BTEX) are monoaromatic
hydrocarbons found frequently in petroleum and its derivatives; and
they are among the most important pollutants of soil and groundwater.
This study focused on harnessing the enzymatic capabilities of
filamentous fungi Gliocladium sp. and Aspergillus terreus, dwelling in
a petroleum-contaminated soil to degrade benzene, toluene, ethylbenzene
and xylene (BTEX) compounds. The biodegradation experiment was carried
out using the fungi individually and in consortium in a batch culture
containing mineral salts medium supplemented with 1% v/v BTEX. The
experiments were carried out in triplicates at room temperature on a
rotary shaker (180rpm) for twenty five days and aliquots were taken on
a five day interval to determine the hydrocarbon utilizing fungal (HUF)
count and residual BTEX in order to monitor the rate of biodegradation.
The hydrocarbon utilizing fungal counts were determined by direct
counting using a Neubauer Haemocytometer while, the residual BTEX was
determined using absorbance values measured using a spectrophotometer
and the corresponding concentrations determined from a standard curve.
The highest percentage degradation of BTEX was observed with
Aspergillus terreus (89.1%) while, the least was observed with
Gliocladium sp. (84.4%). The growth peak was attained on the 15th day
in all treatments after which the HUF counts declined. Statistical
analysis showed no significant difference (P>0.05) in the mean
amounts of BTEX degraded and hydrocarbon-utilizing fungal counts
between the treatments. The strains of Gliocladium sp. and Aspergillus
terreus used in this study showed high ability for BTEX degradation
thus, they are potential candidates for bioremediation of soils
contaminated with monoaromatic hydrocarbons
Contribution of Agroforestry to Farmers Wellbeing in Forest Enclave, Edo State, Nigeria
Get PDFAgroforestry has recently been experiencing a surge in interest as a
cost-effective means to enhance food security and well-being. Thus
there is a need to assess its contribution of to farmer\u2019s
wellbeing. Primary data needed for the study were collected through the
administration of questionnaires to agroforestry farmers. Purposive
random sampling technique was used to select three forest enclaves in
Edo state. A simple random sampling technic was used in the selection
of respondents and a total number of 120 copies of questionnaires were
administered. Data were analyzed using descriptive statistics such as
frequency counts and percentages and inferential statistics such as
Chi-square, Pearson Product Moment correlations (PPMC). The study
revealed that the mean age of the farmers in the area was 45.6years.
Majorities (85.8 %) were male and 78.3% were married. with 54.2% having
household size of between 4 - 6 persons. Majority (84.2%) had formal
education. Also, 65.8% engage in agroforestry farming as their primary
occupation. The results showed that there was positive and significant
relationship between farmers\u2019 involvement in agroforestry and
their economic wellbeing (\u3c72 = 76.27, P 64 0.001), material
wellbeing (\u3c72 = 93.77, P 64 0.001), social wellbeing (\u3c72
= 73.00, P 64 0.001) and psychological wellbeing (\u3c72 =
132.63, P 64 0.001), respectively. It is therefore recommended
that farmers should be encouraged to increase their farm holding and
also organized themselves into association for them to have access to
mechanized equipment
Heavy Metals in Fish Muscle from an Ethiopian Rift-Valley Lake (Hawassa) and a Neighboring Stream (Boicha): Assessment of Human Health Risks
Get PDFConcentrations of heavy metals (Cr, Co, Fe, Ni, Cu, Zn, As, Se, Pb and
Hg) in muscle tissues of two fish species ( Clarias gariepinus and
Oreochromis niloticus ) in an Ethiopian rift-valley lake (Hawassa) and
a neighboring stream (Boicha) were determined. Target hazard quotients
(THQ), hazard index (HI) and target cancer risk (TCR) were used as
indices to evaluate potential human health risks from fish consumption.
Average concentrations of metals decreased in the order
Zn>Fe>Se>Cu>Hg>As>Ni>Cr>Co>Pb and
Zn>Fe>Se>Cu>As>Hg>Cr>Ni>Pb>Co in muscle
tissues of C. gariepinus and O. niloticus, respectively. Mean
concentrations of Hg (0.34\ub10.04 mg kg-1) in muscle tissues of C.
gariepinus from Lake Hawassa, and As (0.18\ub10.05 mg kg-1) as well
as Hg (0.46\ub10.03 mg kg-1) in muscle tissues of C. gariepinus from
Boicha stream were above the safety limits set by WHO/FAO. Likewise,
mean concentrations of As (0.31\ub10.03 mg kg-1) and Hg
(0.19\ub10.05 mg kg-1) in muscle tissues of O. niloticus from Lake
Hawassa and Cr (0.19\ub10.03 mg kg-1), As (0.33 \ub10.04 mg kg-1),
and Hg (0.34\ub10.09 mg kg-1) in O. niloticus from Boicha stream were
also above safety limits. From the results of human health risk
assessments it was concluded that Cr, Cu, Hg and As pose potential
health risks due to consumption of the two fish species from both water
bodies. Moreover, effects of all heavy metals put together may affect
human health as indicated by the high HI. Effluents from industries are
assumed to be the main sources of the heavy metals. Therefore, regular
monitoring of the water bodies and policy interventions with respect to
waste disposal are recommended to protect the health of the ecosystem
and the public
Isolation and Characterization of Larvicidal Phenolic Acids from Kotschya thymodora Leaves
Get PDFMalaria is a vector borne disease responsible for high morbidity,
mortality and poverty in many tropical and subtropical countries. The
disease is transmitted through a bite from an infected female Anopheles
mosquito, amongst which Anopheles gambiae s.s serves as the most
prevalent vector. The control of An. gambiae s.s population can
therefore lead to a reduction in malaria spreading. Previous studies
have reported the crude extracts of Kotschya thymodora to be active
against the larvae of An. gambiae s.s and Culex quinquefasciatus . In
this report the phytochemical study on the crude aqueous ethanolic
extract of K. thymodora leaves led to isolation of vanillic acid (1)
and protocatechuic acid (2). The structures of these compounds and
mosquitoes larvicidal activity against An. gambiae s.s were established
by using spectroscopic techniques and WHO protocol of 1996
respectively. The two phenolic acids exhibited a moderate mosquito
larvicidal activity with LC50 of 77.35 \u3bcg/mL (vanillic acid, 1)
and 62.4 \u3bcg/mL (protocatechuic acid, 2) after 48 hrs exposure
time. This is the first report on the isolation of the two phenolic
acids from plants belonging to the genus Kotschya and their larvicidal
potential against An. gambiae s.s
A pre-test post-test assessment of non-invasive keratograph break up time and corneal epithelial thickness after vaping
Get PDFBackground: The effects of electronic cigarettes on the ocular surface
has yet to be shown. The purpose of the study was to assess the impact
of e-cigarette use on the anterior corneal surface integrity. Methods:
Forty three males and 21 females with an average of 21years were
required to vape 0.05ml of e-liquid of 8mg nicotine concentration.
Corneal epithelial thickness (CET) and Non Invasive Keratograph Tear
Break up Time (NIKBUT) measurements were obtained prior to and post
vaping. The Optovue iVue optical coherence topographer was used to
measure central; superior; inferior; nasal and temporal CET and NIKBUT
was assessed using the Oculus Keratograph 5M. Results: There was a mean
increase for central corneal epithelial thickness of 0.3448 microns.
The superior CET increased by 0.2414 microns. The inferior CET
increased by 0.2931microns. The nasal CET increased by 0.2069 microns.
The temporal CET increased by 0.2759 microns. The mean change in NIKBUT
post-vaping was an increase of 1.40 seconds. All observations occurred
at p > 0.05. Conclusion: The acute effect of e-cigarette use does
not impact corneal epithelial thickness and non-invasive keratography
tear break up time after 10 puffs mild exposure but more research is
needed to assess if this remains the case with more frequent, higher
exposure
Knowledge about modifiable risk factors for non-communicable diseases adults living with HIV in Rwanda
Get PDFBackground: Non-communicable diseases (NCD) are of international public
health concern. Of more concern are people living with HIV (PLHIV), who
have the increased risk of developing NCDs, such as hypertension,
stroke and diabetes. Research has revealed that there is a relationship
between knowledge of NCD risk factors and risk perceptions in the
general population. Therefore, an assessment of PLHIV\u2019s NCD risk
factors knowledge is quite critical, to design effective NCD prevention
programmes. Objective: To assess the level of knowledge of modifiable
risk factors for NCDs and its associated factors among adults living
with HIV in Rwanda. Methods: A cross-sectional quantitative design was
used to collect the data. The study targeted PLHIV who visited the
out-patients\u2019 public health centres in three purposively selected
provinces of Rwanda. The knowledge assessment questionnaire relating to
risk factors for chronic diseases of lifestyle was used to collect the
data. Data were analysed using SPSS version 23. Results: Of the 794
respondents, 64.6% were women, and the mean age was 37.9 (\ub110.8)
years. The results revealed that the majority of the respondents
(65.0%) had low levels of knowledge about NCD risk factors, while some
(35.6%) were of the opinion that they had a low risk of contracting
NCDs. Good knowledge was significantly associated with high educational
status, a low CD4+ cell count (< 350 cells/mm3) and normotension.
Conclusion: The current study findings highlight the need for
comprehensive health education, to raise awareness of non-communicable
diseases\u2019 risk factors for adults living with HIV in Rwanda
Uptake and utilization of institutional voluntary HIV testing and counseling services among students aged 18-24 in Kenya\u2019s public Universities
Get PDFBackground: Kenya is home to an estimated 1.7 million people living
with HIV/AIDS. According to the Kenya AIDS Indicator survey KAIS 2012,
HIV prevalence in the age group 15-24 stood at 2.2%. Globally, young
people aged 15-24 are a highly vulnerable population with respect to
HIV/AIDS infection and transmission. HIV testing and counseling
services play a critical role as an entry point to care and treatment.
However, uptake of HIV testing and counseling services among the youth
in Kenya has been reportedly low. Youths at Universities are among the
priority populations in HIV/AIDS programs. Objectives: This study aimed
to determine the barriers to uptake and utilization of
institution-based voluntary counseling and testing VCT services among
students aged 18-24 in selected public universities in Kenya. The
specific objectives were to determine the factors associated with
uptake and utilization and the association between various
socio-demographic factors and service uptake in institutional VCT
facilities. Methods: This research utilized a descriptive
cross-sectional study design where primarily, data was collected using
semi-structured questionnaires and through focus group discussions held
with the students in the sampled Universities. Data available at Jomo
Kenyatta University of Agriculture and Technology JKUAT Hospital VCT
were reviewed for the period 2010 and 2016 to give an insight into
service utilization rates among students. Multi-stage sampling
technique was utilized to reach a student sample size of 305 from the
selected public Universities in Kenya. Results: Uptake of institutional
VCT services among University students sampled stood at 45% from a
population where 84.4% were aware of the presence of these services on
their campuses. More males than females utilized the services. Emerging
themes from the study indicated that participants utilized the services
for different reasons. Accessibility to test site, testing hours, fear
to be seen at site and fear of test result were also identified as
factors affecting service uptake. These factors also were also reported
when students were asked about their desired characteristics of a VCT
facility on campus. Conclusion: This study has unraveled the factors
that are associated with testing and counseling in institutional
facilities. University students seem to seek and utilize VCT services
for different reasons. It is also clear that patterns of services
utilization vary from group to another as observed in the case of year
of study, gender and age category. Recommendations: It is necessary for
policy makers in institutions of higher learning together with those
tasked with managing healthcare services in these institutions to adopt
approaches that will overcome the barriers to utilization of VCT
services among students. With knowledge of the factors associated with
uptake and utilization of VCT services in institutional facilities,
efforts to tackle the barriers and maximize on enhancers should be
utilized fully in order to improve uptake and utilization of services.
More research should also focus on the persisting risky sexual
behaviors among University students despite the high knowledge they
have on HIV/AIDS