College of Engineeringhttp://etd.dbu.edu.et:80/handle/123456789/52024-03-28T16:26:06Z2024-03-28T16:26:06ZFabrication of Ceramic Capacitor from Metal Oxides (ZrO2, TiO2 & BaO) and Geominerals from the North Shewa Zone (Clay & Bentonite)Lidiya , Mitiku keneahttp://etd.dbu.edu.et:80/handle/123456789/13472023-12-20T08:30:02Z2022-12-01T00:00:00ZFabrication of Ceramic Capacitor from Metal Oxides (ZrO2, TiO2 & BaO) and Geominerals from the North Shewa Zone (Clay & Bentonite)
Lidiya , Mitiku kenea
Ceramic capacitors are fixed-value capacitors made of ceramic material as the dielectric. Ce-
ramic capacitors are one of the most promising electrical energy storage technologies due to
their fast storage capacity, long cycle stability, high power density and environmental friendli-
ness. In this work, the researcher investigated the production of ceramic capacitor material
from metal oxides and geominerals found in the North Shewa zone of Ethiopia's Amhara region.
At a proportion of Titanium dioxide 32%, Zirconium (IV) oxide 46.1%, Barium Oxide 6.9%,
Bentonite 4.9% and Clay 9.8%. The chemical compositions of the Bentonite and Clay were
characterized by the Classical silicate analysis method. The effect of pressing pressure, sintering
temperature and soaking time was determined for each test sample and the electrical properties
of the ceramic capacitor were studied in this research. The specimen was compacted at different
pressing pressures from 40 MPa to 60 MPa. The green mass dried overnight in the oven at 100
℃. The specimen was sintered at different temperatures from 1350℃ to 1450℃ for 1 hr. to 3
hrs. at a soaking firing rate of 5 ℃/minute. The produced ceramic capacitors were characterized
in terms of bulk density (2.6346g/ml-3.5307g/ml), apparent porosity (1.8395%-10.1182%), water
absorption (0.5439%-3.0611%), linear shrinkage (5.1098%-12.89%), Vickers hardness
(KgF/mm2) (329-425.9), and dielectric strength (54.49 kv/mm-74.94kv/mm). the validation of the
developed models was determined. To optimize the dielectric strength of the ceramic capacitor
sample, the optimum process parameters are at a sintering temperature of 1449.85℃, pressing
pressure of 57.9 MPa and soaking time of 2.87hrs. The microstructural investigation of the ce-
ramic capacitor for this work was carried out by XRD.
2022-12-01T00:00:00ZPoultry Feed Formulation and Characterization From Cake of Castor Seed And By- Products of Cassava RootAsnake, Helia Tirunehhttp://etd.dbu.edu.et:80/handle/123456789/13462023-12-20T08:25:59Z2015-01-01T00:00:00ZPoultry Feed Formulation and Characterization From Cake of Castor Seed And By- Products of Cassava Root
Asnake, Helia Tiruneh
The world population is rapidly increasing. The rapidilly increasing world population is
demanding more food. Addresing this demand requres growth in agricultural outputs including
eatable animals (livestock, poultry, and fish) and, their products. However, these animals by
themselves need food, which is usually competing with human food. Besides, some animals and
human foods are industrially competitive,which makes feedsless available and costly. As a result,
the cost of animals and animal products is drastically increasing. Thus, to address these tradeoffs
either optimize the consumption of the feeds or looking for alternative feeds is required for poultry
feeding. This study focuses on Poultry feed synthesis and characterization from castor seed and
cassava root by-products.Cake left after solvent extraction was detoxified with a chemical method
(lime treatment 10gm/kg cake) followed by a physical method (autoclaving at 15 psi for 30 min)
and the ricin level was quantified with UV spectroscopy. The cassava by-products was prepared
by extracting the starch from fresh cassava root through sedimentation and filtration process and
the cyanide content of the cassava root was determined by UV spectroscopy.The result showed
that insignificant ricin was found in castor cake and the cyanide content of the cassava root was
10mg/kg. Then afterThe poultry feed was synthesized by mixing each raw material according to
poultry feed preparation FAO standards. Proximate analysis of the feed was moisture content of
10% ,carbohydrate content of 59.1% ,Crude protein content of 21% ,fat content of 2.2 % ,Ash
content of 4.5 % ,Fiber content of 3.4%.The prepared feed was checked for palatability for broiler
chickens and theier average daily gains were calculated. For optimization, the average daily gain
was taken as a response with three level factors: castor cake, cassava cake, and maize dosages.
Response surface methodology (RSM) in combination with Box -Behnken Design was used to
optimize the operating parameters. The optimization result showed that 25% castor cake,40%
cassavaby-productss and, 10% maize were the optimum values which gave 76.83gm an average
daily gain
2015-01-01T00:00:00ZSynthesis, Characterization and Optimization of Bionanocomposites for the Application of Methylene Blue Dye Degradation under Light IrradiationSalem, Yohannes Menahttp://etd.dbu.edu.et:80/handle/123456789/13452023-12-20T08:22:05Z2022-12-01T00:00:00ZSynthesis, Characterization and Optimization of Bionanocomposites for the Application of Methylene Blue Dye Degradation under Light Irradiation
Salem, Yohannes Mena
Water hyacinth (Eichornia crassipes) is a free floating aquatic weed that potentially damages
the aquatic ecosystem by colonizing rapidly and it causes drying of water bodies. In addition,
releasing of colored textile wastewater into nearby water bodies potentially damage the aquatic
creatures and surrounding lives. But behind the negative assumptions of Water hyacinth (WH)
weed, it is rich in natural fiber content, namely cellulose and its leaves used as a reducing and
capping agent during nanoparticles (NPs) synthesis. Therefore; this research mainly focus on
utilization of the weed’s stem and leaves to develop cellulose nano crystals (CNCs) and as
capping and reducing agent during silver doped zinc oxide nanoparticles (Ag@ZnO NPs)
synthesis, respectively. Furthermore; the developed CNCs to behave as a photocatalyst, it was
combined with a green synthesized Ag@ZnO NPs to develop a bionanocomposite (BNC). The
characterization techniques i.e. UV-Vis spectrophotometer, FTIR, XRD, TGA, BET, DLS and
SEM-EDX were confirm the obtained CNCs and Ag@ZnO NPs were effectively synthesized. Also
each characterization results exhibit the formation of pure BNCs (i.e. CNC/Ag@ZnO (1:1),
CNC/Ag@ZnO (1:0.5) and CNC/Ag@ZnO (0.5:1)). The synthetic Methylene Blue (MB) dye
solution and real textile wastewater were used in photodegradation study. Moreover, the effect
of operating parameters i.e. pH, BNCs dosage, initial MB concentration, and irradiation time
was investigated under sunlight irradiation. According to the results, CNC/Ag@ZnO (1:0.5)
BNC has higher photodegradation efficiency (98.8%) than CNC/Ag@ZnO (1:1) and
CNC/Ag@ZnO (0.5:1) BNCs at the optimum condition. In addition, the RSM-BBD analysis
results showed that pH = 10, CNCs/Ag@ZnO (1:0.5) BNC dosage =18.075 mg/L, MB dye
concentration = 17.468 mg/L and Irradiation time = 111.855 min were the optimal level of the
studied process parameters using CNC/Ag@ZnO (1:0.5) BNC. Also, the desirability of the
process was 1.00; it confirms the acceptance and applicability of the model. Moreover, the
recyclability test confirms CNC/Ag@ZnO (1:0.5) BNC has high recyclability efficiency even
after 7th round than the left synthesized BNCs. Therefore; the facile synthesis and high
degradation efficiency of CNC/Ag@ZnO (1:0.5) BNC photocatalyst make it a promising
candidate for real-world dye containing textile wastewater treatment under light irradiation with
low operating cost.
2022-12-01T00:00:00ZRemoval of Hexavalent Chromium from Synthetic and Armament Engineering Industry Waste Water by Using Activated Carbon-Graphene Oxide CompositeYohana , Tadiwoshttp://etd.dbu.edu.et:80/handle/123456789/13432023-12-20T08:12:29Z2022-12-01T00:00:00ZRemoval of Hexavalent Chromium from Synthetic and Armament Engineering Industry Waste Water by Using Activated Carbon-Graphene Oxide Composite
Yohana , Tadiwos
Nowadays, developing cost effective, and non-hazardous materials for the removal of toxic heavy
metals discharged from industrial wastewater is one of the major challenging problem of the world
particularly, developing countries. Among the different toxic heavy metals, Hexavalent chromium
(Cr (VI)) is one of the most known toxic heavy metal and serious environmental concerns due to its
long persistence in the environment and highly deadly nature in living organisms discharged from
electroplating process, painting, tannery, and metal work industries. Hence, this study mainly
focuses on the synthesis of activated carbon from corncob, sawdust and bamboo, and activated
carbon-graphene oxide composite (BAC/GO) for the application of Cr (VI) adsorption. The most
effective AC was synthesized from bamboo. Furthermore, the bamboo activated carbon combined
with electrochemically exfoliated graphene oxide was synthesized to increase the adsorption
efficiency of activated carbon prepared from bamboo. The synthesized materials were characterized
using different techniques i.e. UV-Vis spectrophotometer, FTIR, XRD, TGA, DLS, BET, and SEM-
EDX. The results confirmed that the developed activated carbon and composite successfully
synthesized. From the single effect study the highest adsorption efficiency of bamboo activated
carbon was 99.18% at the optimum process conditions of adsorption factors. Additionally, the
kinetics of the adsorption was well-fitted to pseudo-second order (R2 =0.9998) and the corresponding
rate constants were obtained. The isotherm of adsorption of corncob activated carbon, sawdust
activated carbon, bamboo activated carbon, and BAC/GO composite was well-fitted to freundlich
isotherm (R2 = 0.9835, 0.9733, 0.9634, and 0.9755, respectively) than Langmuir isotherm. The
developed model‟s validation and interaction effects between process parameters were investigated
by Box Behnken Design and the maximum Cr (VI) adsorption efficiency (99.34%) was attained at PH
(2), adsorbent dose (2.5mg/L), initial Cr (VI) ion concentration (12.5mg/L), and contact time (90
min). Also at this optimum operating conditions the adsorption efficiency of corncob activated
carbon, sawdust activated carbon and bamboo activated carbon were examined and the obtained
result was (90.5%, 94.8%, and 98.95%), respectively. Moreover, the Cr (VI) adsorption efficiency of
BAC/GO composite was investigated using real Armament engineering industrial wastewater and the
obtained adsorption efficiency was (99.85 %). Generally, this study demonstrates that the developed
BAC/GO composite was synthesized from waste and it has excellent adsorption capacity, easy to
prepare and use, cost effective and non-hazardous than corncob activated carbon, sawdust activated
carbon and bamboo activated carbon.
2022-12-01T00:00:00Z