Departments of Physics

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DEGENERATE SQUEEZED LIGHT WITH COHERENT AND THERMAL LIGHTS
(HAWASSA UNIVERSITY, 2017-11) KASU ABEBE BELAY
The squeezing and statistical properties of the light produced by the degenerate threelevel laser whose cavity contains nonlinear crystal generating squeezed light and the cavity mode is driven by coherent light and coupled to thermal reservoir have been studied and applying c-number expectation value of the cavity mode variables associated with the normal ordering at steady state, the quadrature variances, squeezing and the mean and variance of the photon number have been determined. It is found that the effect of the thermal reservoir is to increase the mean photon number and decreases the quadrature squeezing. The presence of nonlinear crystal in the cavity increases both the mean photon number and the quadrature squeezing.
THE EFFECT OF DEPOSITION TEMPERATURE ON STRUCTURAL AND OPTICAL PROPERTIES OF CdS THIN FILM BY USING CHEMICALBATH DEPOSITION METHOD
(HAWASSA UNIVERSITY, 2024-04) Dawit Ewnetie Temesgen
Cadmium sulphide is an intrinsic n-type semiconductor material with the chemical formula CdS. CdS thin films where deposited on glass substrates using cadmium sulphate as the cadmium ion source, thiourea as the sulphur source, and ammonia as the complexing agent through the chemical bath deposition method . The effect of deposition temperature ranging from 400C to 800C in 100C intervals on the structural and optical properties of thin films was investigated. The films were annealed at 3000C for 1:30 hours. The CdS thin films were characterized using XRD for structure and UV-VIS spectrophotometer for optical property determination. Optical investigations revealed that CdS exhibited high absorption in the visible region, with the optical band gap from 1.80 eV to 1.37 eV as the temperature increased. This indicates an inverse relationship between deposition temperature and band gap energy, making these thin films suitable as absorber materials for solar cell fabrication. XRD analysis showed that the deposited CdS thin films had a simple hexagonal crystal structure with preferred orientation along the (002) plane. The intensity of the sharp peak indicates that the sample is highly crystalline. Additionally, the crystalline size of the CdS thin films increased with the higher bath temperatures. Generally, varying the deposition temperature had effect on the structural and optical properties of cadmium sulphide thin films.
OPTICAL AND STRUCTURAL STUDY OF ZINC SULFIDE THIN FILMS AT VARIOUS DEPOSITION TEMPERATURES BY CHEMICAL BATH DEPOSITION METHOD
(HAWASSA UNIVERSITY, 2024-05) MENGISTU MENDEDO
Researcher was able to successfully deposit zinc sulfide (ZnS) thin films on glass substrates using chemical deposition method. The author employed ammonium hydroxide and hydrazine hydrate as complexing agents, which helped control the chemical reactions. Thiourea acted as the source of sulfide (S2-) ions, while zinc chloride provided the zinc (Zn2+) ions needed to form the ZnS compound. Author then characterized the structural and optical properties of the deposited ZnS thin films .The author used X-ray diffraction (XRD) to probe the crystal structure and found that the films had an amorphous (non-crystalline) nature, likely due to the very small size of the crystallites that formed. To understand the optical behavior, we performed UV-visible spectroscopy. This revealed some interesting trends - the band gap energy, which is a key property determining the material's optical abilities, decreased from 3.51eV to 3.45eV as the deposition temperature was increased from 45°C to 60°C. Interestingly, the light absorption of the films increased with higher deposition temperatures. Further analysis showed that the optimal deposition temperature for these ZnS thin films was 55°C, where the optical properties were most favorable. . Overall, this study provides valuable insights into tuning the optoelectronic characteristics of ZnS thin films by carefully controlling the deposition temperature - an important parameter in thin film fabrication. The findings could have implications for applications like solar cells, light-emitting diodes, and optical coatings.
OPTICAL AND STRUCTURAL STUDY OF ZINC SULFIDE THIN FILMS AT VARIOUS DEPOSITION TEMPERATURES BY CHEMICAL BATH DEPOSITION METHOD
(HAWASSA UNIVERSITY, 2024-05) MENGISTU MENDEDO
Researcher was able to successfully deposit zinc sulfide (ZnS) thin films on glass substrates using chemical deposition method. The author employed ammonium hydroxide and hydrazine hydrate as complexing agents, which helped control the chemical reactions. Thiourea acted as the source of sulfide (S2-) ions, while zinc chloride provided the zinc (Zn2+) ions needed to form the ZnS compound. Author then characterized the structural and optical properties of the deposited ZnS thin films .The author used X-ray diffraction (XRD) to probe the crystal structure and found that the films had an amorphous (non-crystalline) nature, likely due to the very small size of the crystallites that formed. To understand the optical behavior, we performed UV-visible spectroscopy. This revealed some interesting trends - the band gap energy, which is a key property determining the material's optical abilities, decreased from 3.51eV to 3.45eV as the deposition temperature was increased from 45°C to 60°C. Interestingly, the light absorption of the films increased with higher deposition temperatures. Further analysis showed that the optimal deposition temperature for these ZnS thin films was 55°C, where the optical properties were most favorable. . Overall, this study provides valuable insights into tuning the optoelectronic characteristics of ZnS thin films by carefully controlling the deposition temperature - an important parameter in thin film fabrication. The findings could have implications for applications like solar cells, light-emitting diodes, and optical coatings
Studying The Effect Of Metallic Precursor Concentration On The Structural And Optical Properties Of Zinc sulfide Thin Films Synthesized By Chemical Bath Deposition Method
(2024-05) Olchitu Bekele
Zinc sulfide (ZnS) thin films with different concentrations of zinc chloride (0.3M, 0.5M, 0.7, 0.9M and 1.1M) have been deposited on a glass substrate made by chemical bath deposition technique in basic medium. Zinc chloride, thiourea, ammonia, and hydrazine hydrate were used to synthesize ZnS thin films. The films were annealed at 200°c. This study investigates how the concentration of metallic precursor affect the crystal structure and optical properties of Zinc sulfide thin films. The XRD result shows that no sharp peak which indicates the samples is amorphous nature. UV-Vis spectroscopy was used to analyze the optical characteristics of the deposited thin films. The absorbance increase with increasing of the zinc sulfide concentration and the band gap energy for the films prepared in different concentration of zinc chloride decrease from 3.53 to 3.42 eV with increasing of zinc sulfide concentrations. The results demonstrated that concentration of metallic precursor have distinct effects on optical absorbance and band gap energy.
A Thesis Submitted to School of Graduate Studies College of Natural and Computational Science in Partial Fulfillment of the Requirements for the Degree of Master of Science in Physics.
(2024-05) Negash Gimbo
In this work, theoretical predicted production cross section were made using COMPLETE, EMPIRE-3.2 and TALYS-1.95(G) reaction model codes for the production of medically important 88Y, 89Zr, 90Y and 99Mo radionuclides in the interaction of α-projectile with 89Y and 96Zr-targets at ≈10-60 MeV. The theoretical predicted production cross sections were compared with the experimental data available in the EXFORE database. The TALYS-1.95(G) code predicted production cross sections of medically important 88Y, 90Y, and 89Zr radionuclide, in general, are found to be in good agreement with experimental measured production cross sections over the entire energy range except for 99Mo radionuclide. Pearson‟s statistical coefficients confirmed a strong positive correlation between TALYS-1.95(G) codes predicted and experimentally measured production cross section except for 99Mo. Furthermore, it was found that the TALYS-1.95(G) predicted and experimentally measured production cross-sections in general attained maximum values below ≈45MeV α-energy for medically important 88Y, 90Y, and 89Zr radionuclides via complex (α,x) channel. Thus the obtained result can be used as reference cross-section data for optimized production of medically important 88Y, 90Y, 89Zr and 99Mo radionuclides using single α + 89Y, 96Zr system.
A Study of Incomplete Fusion Reaction and its Correlation with Projectile Energy and Entrance channel Mass-Asymmetry in some 12C/16O-Induced Reactions at ≈3–9 MeV/nucleon
(HAWASSA UNIVERSITY, 2024-05) Mustefa Kedir Dubiso
In this work, the effects of projectile energy and entrance channel mass-asymmetry on incomplete fusion reaction in 12C + 128Te, 12C + 141Pr, 12C + 159Tb, 16O + 130Te, 16O + 159Tb and 16O + 181Ta, projectiles + targets systems at ≈ 3-9 MeV/nucleon were studied. Cross sections of various reaction products populated via complete and incomplete fusion of 12C projectile with 128Te, 141Pr and 159Tb-targets and 16O projectile with 130Te, 159Tb and 181Ta targets were calculated using the reaction model code PACE4. The predicted cross sections were compared with experimentally measured data from EXFOR database. For a representative non α-emitting ( 12C, 4n) channel from a representative in 12C + 159Tb system, experimentally measured cross sections agreed with PACE4 prediction for level density parameters K=10. For the same level density parameters a representative α-emitting (12C, α3n) from a representative in 12C + 128Te projectile + target system, the experimentally measured cross sections are higher than the PACE4 predicted. The observed difference is attributed to the contribution of incomplete fusion following the prompt break-up of the projectiles into α-clusters. An attempt was made to deduce the contribution of incomplete fusion reactions from presently investigated projectile and target systems. It was found that the incomplete fusion fraction, in general, increases with the increase in projectile energy. Furthermore, the result indicated that at the same normalized relative velocity, the incomplete fusion fraction is higher for mass-asymmetric projectiles and targets systems
A Thesis Submitted to School of Graduate Studies College of Natural and Computational Science in Partial Fulfillment of the Requirements for the Degree of Master of Science in Physics.
(HAWASSA UNIVERSITY, 2024-05) Tekalegn Mitiku
This work studied the production cross section and yield of medically important radionuclides, such as 68Ga and 64Cu, generated during irradiation of 66Zn-target with α-projectile at ≈ 10-40 v MeV. The experimental cross-sections taken from the EXFOR database were compared with the theoretical model calculations using nuclear reaction model codes COMPLETE, TALYS1.95 (G), and EMPIRE3.2. A good agreement was achieved for the measured data and calculated production cross-section using the TALYS1.95 (G) code. The 68Ga and 64Cu yields were computed using TALYS1.95 (G) predicted cross-section data. Also, the possible isotopic impurities were identified, and their contributions were estimated. Based on the yield calculations, the production yield of 68Ga was found to be 39.6 GBq/μAh, at 28 MeV without any significant contribution from its isotopic impurities 67Ga and 66Ga; in addition a yield value of 85.9 MBq/μAh at 40 MeV was obtained for medically important 64Cu radionuclide with negligible isotopic impurities contributions from 66Cu and 62Cu radionuclides
THE EFFECT OF DEPOSITION TIME ON COPPER OXIDE THIN FILMS D
(HAWASSA UNIVERSITY, 2024-06) ASHEBIR WONDAFRASH KIDANE
This paper reports the preparation of Copper Oxide thin films by Chemical Bath Deposition method .The copper oxide thin films were synthesis on glass slide substrates by chemical bath deposition by varying the deposition time using 0.4M of copper acetate, ammonia solution, and hydrazine hydrate. The thin film were deposited by varying deposition time at 15’, 25’, and 35’ at 50oC having the total volume of 70ml. The deposited thin film were red in color, thick, well adhere and uniform. The samples are annealed at 300o c for 1.5hrs. The thin films were characterized by XRD and UV-VIS spectroscopy to investigate the structural and optical phase properties. The structural property was scanned by SHIMADZU XRD-7000 X-ray difractometer 2θ ranging from 10-80o . The XRD result shows all films prepared with deposition time 15’ and 25’ are highly crystalline in cubic Cu2O structure while at the deposition time of 35’additional dominant cubic Cu structure is observed. And the preferred orientation of the film at 15’ and 25’ has 36.38 o along the (111) and at 35’ along the (111) plane of metallic copper. The optical characteristics were identified in the wave length ranging from 400-800nm and the band gap decreased with increasing the deposition time from 2.45-1.75eV. The film deposited at 25' has a band gap of the 1.85 eV. Which similar to the band gap of Cu2O reported by [69]. Although XRD result shows a dominant metallic copper phase at deposition time 35’, UV-Vis result shows the presence of band gap which is in contradiction of XRD result. Therefore further investigation is required. The result shows the decrement of band gap with increasing deposition time. However the band gap and crystalline size doesn’t show correlation. This could be due to varies factor like deposition method, dopant, defects, diffusion and super saturation. That is as the film thickens diffusion of reactant become slower and the solution become supersaturated with copper ion hindering further nucleation; these factors eventually limit crystal growth. And also Ostwald ripening occurs when larger crystal grows at the expense of smaller ones. Then smaller grain dissolves and their material migrate to larger grains. This process reduces the overall crystal size. Generally initially, increasing reaction time leads to larger crystal; beyond a critical point, Ostwald ripening also dominates, causing a decrease in crystal size. The balance between the
EFFECT OF DEPOSITION TIME ON STRUCTURAL AND OPTICAL PROPERTIES OF CdS THIN FILM PREPARED BY CHEMICAL BATH DEPOSITION METHOD IN ALKALINE MEDIUM
(HAWASSA UNIVERSITY, 2024-06) ABERASH BEKENA
Cadmium Sulfide thin films were prepared by chemical bath deposition (CBD) technique at bath temperature of 800C for various deposition time. The bath solution was a mixture of cadmium chloride and thiourea as source of Cd2+ and S2- respectively and ammonia hydroxide was used as complexing agent in basic medium. After deposition the film were annealed at temperature of 3000C for 90min. The effect of deposition time on the structural and optical properties of CdS thin film were investigated by XRD, FT-IR and Uv-Vis spectroscopy characterization technique. The XRD analysis revealed CdS thin film were cubic (Hawleyite) structure. The diffracted peaks are indexed (111),(200), (220) and (311) planes and with preferred orientation along the (111) plane. Estimated crystallite size and optical band gap was found in range of 11.7nm to 16.12nm and 1.8ev to 2.06ev respectively for deposition time 30min to 60min in 10min interval. The functional group of CdS thin films were proposed based on FTIR result obtained. The absorbance generally decreased with increase in wavelength and has relatively low values in the infrared region of the spectrum. A strong absorption was observed at wavelength range of 400 nm to 600 nm.
UV-VISIBLE SPECTROSCOPIC QUANTIFICATION OF SUN SCREENING EFFICIENCY OF SOME HERBAL EXTRACTS AND COMMERCIALLY AVAILABLE BODY CREAMS AND SUNSCREENS IN ETHIOPIA
(HAWASSA UNIVERSITY, 2024-06) KENEAN DAGNE RORISA
In this study, the sun protection factor (SPF) of different plant extracts, as well as commercial sunscreens and body cream, was evaluated using the UV-Visible spectroscopic approach, which is quick, simple, and inexpensive. The in vitro SPF value is estimated using the spectrophotometric method proposed by Mansur et al. After dilution with ethanol solutions, five herbal extracts, Ocimum lamifolium hochst (Damakese), Rhamnus prinoides (Gesho), Vernonia amygdalina (Grawa), Thymus schimperi (Tosign), and Trigonella foenum-graecum (Abish), were prepared, and the absorbance was measured between 290 nm and 320 nm. All of the examined herbal extracts were found to have some level of UV protection; the highest SPF value was 5.86 for Rhamnus prinoides (Gesho) extract, while the lowest was 0.93 for Ocimum lamifolium hochst (Demakese) extract. The same technique was applied to determine the SPF values of commercial body cream and sunscreens. The examined samples, Lady Diana, Valera, Dr. Rachel, and Super White's - labeled SPF values were in the range of 30 and 60. After evaluation, the results of the analysis showed that all of the selected samples had SPF values lower than what was written on the label. This discrepancy raises questions about the product's effectiveness and reliability. Commercial products shield the skin from UV rays; however, prolonged exposure may result in negative effects on the skin. The impact of chemical sunscreens must be countered by an alternative. This study examined the possible photo-protective qualities of natural substitutes, especially herbal extracts, in response to these concerns.
ANALYSIS OF HEAVY METAL CONCENTRATIONS IN COATINGS OF SCRATCH LOTTERY CARDS AND SCRATCH PHONE RECHARGE CARDS IN ETHIOPIA USING FLAME ATOMIC ABSORPTIONS SPECTROSCOPY
(HAWASSA UNIVERSITY, 2024-06) KEDIR EDAO WABE
This research work was focused on the presence and level of heavy metals in coatings of scratch mobile cards and lottery cards in Ethiopia using flame atomic absorptions spectroscopy .The study mainly stressed on heavy metals such as Copper, Lead, Manganese, Chromium, and Nickel, so that the coatings of this scratch mobile cards and lottery cards were acidic digested for the determinations of the presence and levels of heavy metals concentrations. According to the laboratory results the concentrations of heavy metals in certain amounts in all these heavy metals indicated above and when we saw the levels and concentration of this heavy metals one by one with a value Cu(0.954,1.07) ,Pb(0.085,0.071), Mn(0.084,0.055), Cr(0.073,0.060) and Ni(0.051,0.041) in ppm respectively for both mobile recharge and lottery cards. This indicated that heavy metals Cu had the largest value as we compared with heavy metals and heavy metals Ni had the least and the rest heavy metals were next to the copper metal respectively for both mobile recharge cards and lottery cards and the calibrations of concentration to absorbance would obtained the result and the concentration of heavy metals in coatings of scratch mobile recharge cared and lottery cards in standards solution and its within R2 (0.994-0.999). Although the concentrations of all this heavy metal in the scratch cards are low, over time they can accumulate on the environment if not properly disposed, and can cause health problems as they are poisonous and dangers to human health when taken above the limit set by WHO. Therefore public awareness become advised not to use finger nails to scratch mobile recharged card and lottery cared rather it is advisable to use sharp edge materials in order to scratch this mobile recharge cards and lottery cards
UV-VISIBLE SPECTROSCOPIC QUANTIFICATION OF SUN SCREENING EFFICIENCY OF SOME HERBAL EXTRACTS AND COMMERCIALLY AVAILABLE BODY CREAMS AND SUNSCREENS IN ETHIOPIA
(2024-06) KENEAN DAGNE RORISA
In this study, the sun protection factor (SPF) of different plant extracts, as well as commercial sunscreens and body cream, was evaluated using the UV-Visible spectroscopic approach, which is quick, simple, and inexpensive. The in vitro SPF value is estimated using the spectrophotometric method proposed by Mansur et al. After dilution with ethanol solutions, five herbal extracts, Ocimum lamifolium hochst (Damakese), Rhamnus prinoides (Gesho), Vernonia amygdalina (Grawa), Thymus schimperi (Tosign), and Trigonella foenum-graecum (Abish), were prepared, and the absorbance was measured between 290 nm and 320 nm. All of the examined herbal extracts were found to have some level of UV protection; the highest SPF value was 5.86 for Rhamnus prinoides (Gesho) extract, while the lowest was 0.93 for Ocimum lamifolium hochst (Demakese) extract. The same technique was applied to determine the SPF values of commercial body cream and sunscreens. The examined samples, Lady Diana, Valera, Dr. Rachel, and Super White's - labeled SPF values were in the range of 30 and 60. After evaluation, the results of the analysis showed that all of the selected samples had SPF values lower than what was written on the label. This discrepancy raises questions about the product's effectiveness and reliability. Commercial products shield the skin from UV rays; however, prolonged exposure may result in negative effects on the skin. The impact of chemical sunscreens must be countered by an alternative. This study examined the possible photo-protective qualities of natural substitutes, especially herbal extracts, in response to these concerns.
ATOMIC ABSORPTION SPECTROSCOPIC ANALYSIS OF HEAVY METAL CONTENTS OF MALT BEVERAGES CONSUMED IN ETHIOPIA
(HAWASSA UNIVERSITY, 2024-06) MARISHET TESSEMA TAMIRU
This study was designed to detect the levels of some heavy metals such as, nickel, cobalt, chromium, lead, and copper in five different brands of malt beverages commonly consumed in Ethiopia (Sinq, Sofi, Nigus, Malta Guinness and Bertat), using flame atomic absorption spectrometry (FAAS). The heavy metal contents obtained using FAAS shows slight differences among the five malt beverages. Generally in all brands of malt beverages, the concentration of Cu is the highest and Ni has the lowest concentrations. The order of abundance of these heavy metals is: Cu > Co > Cr > Ni. The levels of Ni and Cr show very small variations among the different brands of malt beverages. On the other hand, concentrations determined for Cu, Co shows slightly higher variations among the different brands. The level of Cobalt (Co) concentrations are in the range between 0.048 mg/L and 0.073 mg/L, which is above the maximum limit that has set by WHO (0.01 mg/L) in five malt beverages. The Ni level obtained in the beverages range between 0.015 mg/L and 0.029 mg/L, which is above the maximum limit set by WHO (0.02 mg/L) except the Bertat that has concentration range 0.015mg/L. The concentration of Cu is in the range from 0.4 mg/L to 0.68 mg/L, while the maximum allowed value set by WHO has 2.0. Therefore the levels of Cu in all the samples are within the acceptable limit. The level of Cr in the samples range between 0.032 and 0.047 which is again below the maximum allowed limit set by WHO (0.05 mg/L). In all samples, the level of Pb is below the detection limit of the instrument. In general, few malt drinks, the level of some heavy metals are slightly above the maximum limit set by the national and international organizations. Therefore, I suggested that malt beverage producing companies should pay attention to continuous monitoring of the sources of these heavy metals in malt beverages. The experimental results are validated in terms of accuracy, precession, linearity and method of detection limit. The accuracy was determined by spiking experiment and an accepted percentage recovery was obtained in the range of 97%-98%.
QUANTITATIVE ANALYSIS OF ETHANOL CONTENT AND KEROSENE ADULTERATION OF MOTOR GASOLINE IN ETHIOPIA, USING FOURIER TRANSFORM INFRARED SPECTROSCOP
(HAWASSA UNIVERSITY, 2024-06) YORDANOS FEKEDE
The automotive sector in Ethiopia is a major player of economic growth and most activities rely on it. Gasoline is the most often utilized energy source used to power automotives with internal combustion engine; as a result its demand is growing from time to time. Due to the high demand, its quality is usually compromised. Among others, ethanol and kerosene are the most commonly added substances due to their cheaper price, and surplus availability compared to gasoline. According to ISO only 10% Ethanol should be added to gasoline to reduce greenhouse gas emission. However, in many countries including Ethiopia, there is no strict control on the amount of ethanol and the presence of kerosene in gasoline. Some random investigations showed that there are illegal adulteration practices on most gasoline stations [40]. Detecting adulterants and determining ethanol content can’t be done by visual inspections due to their similarity and miscibility with the actual gasoline acquiring analytical techniques. This study aims to quantify ethanol content and kerosene adulteration in five gasoline brands from gas stations located in Hawassa city, Ethiopia using FT-IR spectroscopy. The ethanol content is determined by using the absorption peaks aroused from O-H and C-H stretching vibrations and the kerosene adulterations detected using absorption peaks in 1378 and 1460 region of IR spectrum. The later peaks are believed to be originated from the CH3 bending vibration. The results obtained by FT-IR technique showed that there is an ethanol blending practice exceeding the limit set by ISO ranging from 2% to 9% and significant kerosene adulteration has also be detected. The results suggest that there are significant kerosene adulteration and ethanol blending noncompliance with gasoline quality standards in gasoline supply chain.
STUDIES OF STRUCTURAL AND OPTICAL PROPERTIES OF LEAD SULFIDE THIN FILM AT DIFFERENT DEPOSITION TIME PREPARED BY CBD TECHINIQUE
(HAWASSA UNIVERSITY, 2024-09) YIRGALEM FIKIRE ALEKER
In this study, PbS thin films were deposited on glass substrates using the chemical bath deposition (CBD) technique. Lead acetate, thiourea, and sodium hydroxide were used as precursors for the Pb²⁺, S²⁻ source, and complexing agent, respectively. The deposition was carried out at a bath temperature of 80°C for varying durations of 20, 25, 30, 35, and 40 minutes. Following deposition, the films were annealed at 200°C for 90 minutes. The structural and optical properties of the films were characterized using X-ray diffraction (XRD) and UV-Visible spectroscopy. XRD analysis revealed that the as-deposited PbS films exhibited a nanocrystalline cubic (galena) structure with a face-centered cubic lattice, showing diffraction peaks corresponding to the (111), (200), (220), (222), (311), (400), (420), (331), and (422) planes, with a preferred orientation along the (200) plane. The crystallite size was estimated to increase from 33.27 nm to 37.50 nm as the deposition time increased. Additionally, both dislocation density and lattice strain decreased with increasing deposition time. Optical absorption measurements revealed strong absorption in the wavelength range of 500 nm to 750 nm. The optical band gap was reduced from 1.62 eV to 1.51 eV as the deposition time increased from 20 to 40 minutes in 5-minute intervals
INVESTIGATION OF LEVELS OF SOME HEAVY METAL PRESENTS IN LIVESTIKE‟S WATER AND RAW MILK IN EAST GUJI ZONE, ETHIOPIA USING ATOMIC ABSORPTION SPECTROSCOPY
(HAWASSA UNIVERSITY, 2024-10) DEBELE NEDI AREDO
In this work heavy metal concentration in row cow milk and live stock water in east Guji Zone were studied using FAAS. The Raw Cow’s milk and water were collected from six farms of Liben bulb, Liben, mugayo, Goro Dola Daraara, Goro Dola Haraqalo and, Wadera Lagu, Wadera Calo site Guji zone, Ethiopia and HNO3 was used in the optimal microwave digestion process to break down the milk and water samples. The heavy metal contents obtained using FAAS show slight different among six samples in cow milk and water. The concentration of Pb, Ni, Co, Cr and Cu were determined by using AAS. Pb, Ni, Co, Cr, and Cu were found in every sample of milk and water. The concentration of Pb, Ni, Co, Cr and Cu, 0.046 - 0.084 mg\L , 0.17 - 0.245, 0.0035 -0.097mg\L, 0.045 - 0.104 mg and 0.161 -0.473 mg\Lin milk and WHO of the above elements 0.04, 0.07, 0.05),0.05,2.0)in cow milk and the concentration of Pb ,Ni,Cr,Cu andCu,0.034- 0.084mg\L,0.134-0.344,0.034-0.295,0.045-0.104and0.026-0.094in water and The WHO above element, 0.01, 0.02, 2.0, 0.05, and 0.05 in water. The concentration Cu and Ni are more than Co, Cr, and Pb in both milk and water, concentrations are generally the lowest in milk and water.
INFLUENCE OF CATIONIC PRECURSOR CONCENTRATION ON THE OPTICAL AND STRUCTURAL PROPERTIES OF COPPER OXIDE THIN FILMS DEPOSITED BY CHEMICAL BATH DEPOSITION TECHNIQUE
(HAWASSA UNIVERSITY, 2024-11) HUSSEN KELLI
Copper oxide thin films were fabricated on glass substrates using the chemical bath deposition method with a deposition time of 20 minutes. The structural and optical properties of the films were investigated using X-ray diffraction (XRD) and optical analyses, focusing on the effects of varying copper acetate((CH3 .COO)2 Cu·H2 O ) as the Cu precursor concentrations., hydrazine (N2 H5 OH) as a complexion agent, and ammonium hydroxide (NH4 OH) as a pH regulator at a bath temperature of 80°C. The films were deposited by adding 1ml, 2ml, 3ml, 4ml, and 5 ml of 0.4 M copper acetate to the bath solution. The films were smooth, well-adherent, uniform, and thick. The films were characterized by X-ray diffraction for structural study and UV-VIS spectrophotometer for the study of optical properties. The XRD study revealed that the films deposited with 1 to 3 ml of copper acetate solution crystallized in the monoclinic phase of the CuO structure, with two prominent peaks at 35.5° and 38.7°, which are indexed to the (002) and (111) planes of the monoclinic CuO structure. The films deposited with 4 and 5 ml of copper acetate had an additional peak at 36.5°, which is indexed to the (111) plane of cubic Cu2 O. Optical studies revealed that the CuO thin films have a direct band transition with values of 2 eV, 1.85 eV, 1.8 eV, 1.95 eV, and 2.2eV for CuO thin films deposited with 1 ml, 2 ml, 3 ml, 4 ml, and 5 ml of copper acetate, respectively
INVESTIGATION OF STRUCTURAL AND OPTICAL PROPERTIES OF MANGANESE DOPED COPPER OXIDE THIN FILM SYNTHESIZED BY CHEMICAL BATH DEPOSITION METHOD
(HAWASSA UNIVERSITY, 2024-11) DESALEGN FENTAHUN TADEGE
This study investigates the synthesis and characterization of manganese-doped copper oxide (CuMnO) thin films deposited onto glass substrates using the chemical bath deposition (CBD) method. The objective were to understand how varying manganese concentrations affect the structural and optical properties of the films. The process involved preparing solutions with varying manganese sulfate concentrations (1.5 ml, 3 ml, 4.5 ml, and 6 ml) and maintaining constant conditions for copper acetate, ammonia and hydrazine. The films were deposited at 50°C for 30 minutes, followed by annealing at a temperature of 300°C for 1 hours and 30 minutes. Structural analysis using X-ray diffraction (XRD) revealed that the films possessed a monoclinic copper manganese oxide and cubic Cu2O structure .The crystallite size initially increased with manganese concentration, reaching a maximum at 4.5 ml, before slightly decreasing. The dislocation density and strain showed corresponding trends, indicating improved crystal quality up to a certain concentration. Optical properties were assessed using UV-Vis spectroscopy. The band gap of the films increased from 1.7 eV to 1.9 eV as the manganese concentration rose from 1.5 ml to 6 ml. This shift in the band gap reflects the impact of manganese doping on the electronic structure of the films, potentially enhancing their suitability for optoelectronic applications. Overall, the results demonstrate that manganese doping effectively tunes the structural and optical characteristics of CuMnO thin films, offering insights into their potential use in various technological applications, including sensors and photovoltaic devices
DETERMINATION OF HEAVY METALS CONCENTRATION IN DIFFERENT BRANDS OF BOTTLE WATER AVAILABLE IN ETHIOPIAN MARKETS BY USING FLAME ATOMIC ABSORPTION SPECTROSCOP
(2024-11) : AYENEW BERHANU LIBEN
Flame atomic absorption spectrometry (FAAS) is a crucial analytical technique widely used in environmental studies to detect and quantify heavy metals. In this research we used FAAS to determine the concentrations of Ni, Cu, Cr, Co, and Pb in 18 different brands of bottled water collected from Ethiopian’s markets. Samples were stabilized with 2% nitric acid and analyzed using flame atomic absorption spectroscopy (FAAS) after precise calibration with standard solutions. The concentrations of Ni, Cu, Cr, Co, and Pb ranged from 0.021 - 0.068 mg/L, 0.021 - 0.084 mg/L, 0.044 - 0.049 mg/L, 0.00 mg/L, and 0.005 – 0.0093 mg/L respectively. The method validation demonstrated excellent linearity, with correlation coefficients (R2 ) of 0.9994, 0.9995, 0.9998, 0.9990, and 0.9999 for Ni, Cu, Cr, Co and Pb, respectively. Precession (%RSD) was within acceptable limits ranging from 0.21% to 8.5% for Ni, 0.0% to 8.8% for Cu, 0.2% to 9% for Cr, and 0.0% to 13.04% for Pb. These values are acceptable as compared to the standard acceptable value of R 2 > 0.999 for linearity and %RSD ≤ 16% for precision based on ICH value. Recoveries (accuracy) ranged from (92.6 – 101.7) % which is within the acceptable range of recovery test of 90% - 110% based on ICH values. The concentration of heavy metals found in all bottled water samples are below the recommended World Health Organization’s (WHO’s) and Ethiopian’s quality guidelines for drinking water for heavy metals so that there is no safety compliance with respect to thi