Papers by Paul Buah-bassuah
Assessment of natural radioactivity, radon gas and soil characteristics along the Volta Lake in the Kpando municipality of Volta region, Ghana
Radiation Protection Dosimetry
Assessment of radionuclides, indoor radon (222RnI), radon exhalation (222Rnex), and soil characte... more Assessment of radionuclides, indoor radon (222RnI), radon exhalation (222Rnex), and soil characteristics in the coastal part of Kpando has been studied using HPGe, CR-39 and sieving techniques. Statistical analysis between radionuclides, radon levels and soil characteristics was done using Pearson’s correlation. The mean radionuclide concentration, radon levels and soil characteristics were obtained as 226Ra (23.1 ± 1.4 Bq per kg), 232Th (34.6 ± 2.9 Bq per kg), 40K (187.1 ± 13.7 Bq per kg), 222RnI (64.70 ± 2.7 Bq per m3), 222Rnex (7.9 ± 0.5 μBq per m2h), sandy (45.9 ± 3.9%), silt (40.7 ± 3.1%), clay (13.5 ± 0.8%), porosity (0.6 ± 0.1) and moisture (7.6 ± 0.8%). Radiological effects estimated were within recommended limits. The maximum positive and negative coefficients exist between 222Ra/222Rnex (1.0) and 222Rnex/MC (−0.9), respectively. Radon exhalation correlates better with soil characteristics. The statistical analysis indicated that soil characteristics have significant effect...
Research Journal of Applied Sciences, Engineering and Technology, Jun 15, 2013
This analysis focused on using Moiré Interferometry method to measure surface defects in woven fa... more This analysis focused on using Moiré Interferometry method to measure surface defects in woven fabrics. A laser imaging system based on moiré Interferometry has been used as a tool for surface defect inspection of static textile fabric. Test textile fabrics samples with five different types of defects (hole, oil stains, warp-lacking, weft-lacking and dirt) were used. With the sample sand witched between two Ronchi rulings and illuminated by an expanded HeNe laser beam to form Moiré configuration. The images from the fabric were acquired with a high resolution CCD camera. The recorded images were transferred to a computer for analysis by the image pro plus 5.0 software. By making use of image processing and FFT techniques, the surface defects such as lack of yarns and oil stains were analysed and detected. During the process of inspection and defect identification, it was observed that the three parameters, textual structure, the shape and size of the defect varied. In this paper, moiré based technique for defect detection is presented. The result of the inspection of the textile fabric on the textile images revealed that FFT analysis serves as a filter in identifying such defects. Also, the fabric texture densities limited the intensity of the laser beam transmission through some fabrics. However, the variation of such intensities helped to deduce that the area covered with stain scatter most of the incident light and the more localised the defect the more the spread out of its transform. It explained the behaviour of the frequency spectrum of each sample and the smaller the width of the yarn spacing, the broader the entire diffraction pattern.
Investigation of Young's modulus of elasticity in wood Using Electronic Speckle Pattern Interferometry (ESPI)
Physical Review E, 1996
We report an experimental investigation of the fragmentation process of a heavy drop falling in a... more We report an experimental investigation of the fragmentation process of a heavy drop falling in a lighter miscible fluid. For fixed liquid composition and for different drop sizes, we observe that the fragmentation cascade stops after a few breakups, once each individual droplet has reduced below a critical volume for further splitting. Since each fragmentation is the outcome of a hydrodynamic instability, we expect fluctuations in the size of the fragmented droplets. The main experimental outcomes are the following: ͑1͒ the first breakup time scales with the size separation from the critical volume in a universal way independent of the fluid composition; ͑2͒ in the region intermediate between the first and the last fragmentation, the droplet sizes display multifractal properties, with the average dimension D 0 decreasing to a minimum and then increasing again once diffusion prevails; and ͑3͒ the droplet height scales with time with an exponent independent of the drop volume and composition. ͓S1063-651X͑96͒00607-1͔
The thermomagnetic effect in a semiconductor superlattice in the presence of laser radiation
Journal of Physics: Condensed Matter, 1993
A theoretical investigation of the photostimulated thermomagnetic effect by electrons in a semico... more A theoretical investigation of the photostimulated thermomagnetic effect by electrons in a semiconductor superlattice (SL) in the lowest miniband is presented. The possibility of controlling the thermopower alpha , the electron thermal conductivity chi and the electroconductivity sigma of the SL with the help of laser radiation is indicated. The parameters alpha , chi and sigma were found to oscillate. The Hall constant, the Righi-Leduc and the Maggie-Righi-Leduc effects were calculated. The prospect of using the SL as a good-quality and highly efficient thermoelement is also proposed.
Measurement of refractive index by double-exposure speckle pattern recording
American Journal of Physics, 1989
An experimental approach is presented to the measurement of the refractive index of materials bas... more An experimental approach is presented to the measurement of the refractive index of materials based on the optical properties of speckle patterns. The sample being characterized is shaped in the form of a plane parallel plate and so inserted in a speckle-forming beam. Speckles are recorded on a photographic plate with a double-exposure technique producing a twin speckle pattern. Decoding of such a recorded pattern leads to the desired information.
Lateral vibrations measurement of powdery clay sample using speckle photography
We report the use of lateral vibration of speckle patterns in studying the particle sizing of bul... more We report the use of lateral vibration of speckle patterns in studying the particle sizing of bulk powdery clay sample. A two-exposure recording was made on a high-resolution holographic plate placed in the observation plane. The first exposure was taken when the laser-speckles without the sample vibrated laterally and the second when the laser-speckles and the sample vibrated laterally together. The plate was photographically processed to obtain a specklegram. The analysis of the fringe pattern from the decoded specklegram gave the particle sizes in the sample.
Laser-induced autofluorescence assisted by multivariate techniques discriminates a cataractous lens from healthy lens tissues of Sprague–Dawley rats
Journal of the Optical Society of America A, 2020
Laser-induced autofluorescence (LIAF), combined with multivariate techniques, has been used to di... more Laser-induced autofluorescence (LIAF), combined with multivariate techniques, has been used to discriminate a cataractous lens from healthy lens tissues. In this study, 405 nm and 445 nm were used as excitation sources to induce the autofluorescence. Results show higher autofluorescence intensity in cataractous lens tissues than in healthy ones. Cataractous lens tissues show a red shift of 0.9 nm and 1.2 nm at 405 nm and 445 nm excitations, respectively. Using principal component analysis (PCA), three principal components (PCs) gave more than 99% variability for both 405 nm and 445 nm excitation sources. Based on the three PCs, Fisher’s linear discriminant model was developed. An accuracy of 100% was obtained in classifying the lens tissues using Fisher’s linear discriminant analysis (FLDA). The LIAF technique assisted by PCA and FLDA may be used for objective discrimination of cataractous lens from healthy lens tissues of Sprague–Dawley rats.
African Review of Physics, 2011
CR-39 SSNTD detects radioactive emissions and by etching provides a means of studying tracks of e... more CR-39 SSNTD detects radioactive emissions and by etching provides a means of studying tracks of emitted particles such as Fission Fragments and alpha particles. A new way of imaging etched fission fragments and alpha tracks in CR-39 detector is presented. A commercial software Image Pro Plus is used in digitizing the images, counting and classifying the tracks. Variations of etched track dimensions with particle energies are presented.
Hybrid quantum erasure scheme for channel disturbance characterization
arXiv: Quantum Physics, 2017
We demonstrate a simple projective measurement based on the quantum eraser concept that can be us... more We demonstrate a simple projective measurement based on the quantum eraser concept that can be used to characterize the disturbances of any communication channel. Quantum erasers are commonly implemented as spatially separated path interferometric schemes. Here we exploit the advantages of redefining the which-path information in terms of spatial modes, replacing physical paths with abstract paths of orbital angular momentum (OAM). Remarkably, vector modes (natural modes of free-space and fibre) have a non-separable feature of spin-orbit coupled states, equivalent to the description of two independently marked paths. We explore the effects of fibre perturbations by probing a step-index optical fibre channel with a vector mode due to the increasing relevance in high-order spatial mode encoding of information for ultra-fast fibre communications.
International Journal of Sciences: Basic and Applied Research, 2018
Radiotherapy forms an essential part in the increase survival and relieve of cancer globally. Tum... more Radiotherapy forms an essential part in the increase survival and relieve of cancer globally. Tumoricidal dose are delivered to cancerous tumours conformal as practically achievable. Radiation delivery mode, dosimetric verification and quality assurance play a key role in prior to patient treatment. The focus of this study is to present a modality for ensuring good quality control prior to treatment delivery using Cobalt ( 60 Co) source. In the study, absorbed dose to water is computed in a virtual phantom with approximate full scatter conditions with gamma as the radiation source. Monte Carlo Neutron Photon (MCNP) code system was used to simulate the properties of the system geometry of the phantom following the International Atomic Energy Agency (IAEA) Technical Report Series 398 protocol. The research was limited to the use of virtual simulation of water phantom for the Cobalt-60 treatment unit. This work provides information recommended for photon energy according to the medical...
A photonic crystal slab was designed in COMSOL Multiphysics using gallium arsen ide (GaAs) pillar... more A photonic crystal slab was designed in COMSOL Multiphysics using gallium arsen ide (GaAs) pillars placed equidistant from each other in air. A defect was created by removing some GaAs pillars across the crystal slab geometry to form a 90 o bend through the struc ture. Structural parameters; the pillar diameter and inter-pillar spacing were separately varied and waves were propagated through the created defect with different allowed wavelengths, within and determined by the photonic crystal's bandgap. It was observed for the air filling fraction at constant pitch that, when the factor given by the ratio of the air hole diameter to the pitch is less than 0.63, an increase in air hole diameter requires corresponding increase in the wavelength which can be propagated within the waveguide with minimum loss. When both air hole diameter and pitch were varied the increase in the air filling fraction was also observed to result in a photonic bandgap of lower frequency range as only larg...
Laser-induced fluorescence combined with multivariate techniques identifies the geographical origin of antimalarial herbal plants
Journal of the Optical Society of America A, 2020
Laser-induced fluorescence (LIF) combined with multivariate techniques has been used in identifyi... more Laser-induced fluorescence (LIF) combined with multivariate techniques has been used in identifying antimalarial herbal plants (AMHPs) based on their geographical origin. The AMHP samples were collected from four geographical origins (Abrafo, Jukwa, Nfuom, and Akotokyere) in the Cape Coast Metropolis, Ghana. LIF spectra data were recorded from the AMHP samples. Utilizing multivariate techniques, a training set for the first two principal components of the AMHP spectra data was modeled through the use of K-nearest neighbor (KNN), support vector nachine (SVM), and linear discriminant analysis (LDA) methods. The SVM and KNN methods performed best with 100% success for the prediction data, while the LDA had a 99% success rate. The KNN and SVM methods are recommended for the identification of AMHPs based on their geographical origins. Deconvoluted peaks from the LIF spectra of all the AMHP samples revealed compounds such as quercetin and berberine as being present in all the AMHP samples.
Journal of Physics Communications, 2018
View the article online for updates and enhancements. Related content Holographic diagnostics of ... more View the article online for updates and enhancements. Related content Holographic diagnostics of fluid experiments onboard the International Space Station U Schnars, K Sommer, B Grubert et al.-Axial sub-nanometer accuracy in digital holographic microscopy J Kühn, F Charrière, T Colomb et al.-An integrated optical setup for fluidphysics experiments under microgravity conditions F Dubois, L Joannes, O Dupont et al.
Optics Communications, 2017
We demonstrate a simple projective measurement based on the quantum eraser concept that can be us... more We demonstrate a simple projective measurement based on the quantum eraser concept that can be used to characterize the disturbances of any communication channel. Quantum erasers are commonly implemented as spatially separated path interferometric schemes. Here we exploit the advantages of redefining the which-path information in terms of spatial modes, replacing physical paths with abstract paths of orbital angular momentum (OAM). Remarkably, vector modes (natural modes of free-space and fiber) have a non-separable feature of spin-orbit coupled states, equivalent to the description of two independently marked paths. We explore the effects of fiber perturbations by probing a step-index optical fiber channel with a vector mode, relevant to high-order spatial mode encoding of information for ultra-fast fiber communications.
Open Journal of Biophysics, 2017
Cataracts are the leading cause of blindness worldwide. Current methods for discriminating catara... more Cataracts are the leading cause of blindness worldwide. Current methods for discriminating cataractous lenses from healthy lenses of Sprague-Dawley rats during preclinical studies are based on either histopathological or clinical assessments which are weakened by subjectivity. In this work, both cataractous and healthy lens tissues of Sprague-Dawley rats were studied using multispectral imaging technique in combination with multivariate analysis. Multispectral images were captured in transmission, reflection and scattering modes. In all, five spectral bands were found to be markers for discriminating cataractous lenses from healthy lenses; 470 nm and 625 nm discriminated in reflection mode whereas 435 nm, 590 nm and 700 nm discriminated in transmission mode. With Fisher's Linear discriminant analysis, the midpoints for classifying cataractous from healthy lenses were found to be 14.718 × 10 −14 and 3.2374 × 10 −14 for the two spectra bands in the reflection mode and the three spectral bands in the transmission mode respectively. Images in scattering mode did not show significant discrimination. These spectral bands in reflection and transmission modes may offer potential diagnostic markers for discriminating cataractous lenses from healthy lenses thereby promising multispectral imaging applications for characterizing cataractous and healthy lenses.
Applied Physics Research, 2016
Malaria parasites, Plasmodium falciparum (P.falciparum) infections are taking a great toll on the... more Malaria parasites, Plasmodium falciparum (P.falciparum) infections are taking a great toll on the lives of people worldwide, especially in developing countries. Recently, haemozoin detection using optical techniques tends to provide comparable parasite densities (PDs) estimation. We conducted feasibility studies on P.falciparum infected blood (i-blood) and uninfected blood (u-blood) samples from volunteers employing laser-induced fluorescence technique for PDs estimation. Fluorescence results show high intensity in u-blood than i-blood. PeakFit analysis with Loess smoothing under Lorentzian curve shows that fluorescence peak of i-blood appears red-shifted with increasing PDs. The Lorentzian curves depict that fluorescence peak intensity ratio increases with increasing PDs in i-blood samples. This technique may be potentially applied in PDs estimation to improve malaria diagnosis.
Applied Physics Research, 2015
Cassava mosaic disease (CMD) is a major constraint to cassava production in cassava growing regio... more Cassava mosaic disease (CMD) is a major constraint to cassava production in cassava growing regions. Severity of CMD symptoms on cassava leaves is usually assessed visually using an arbitrary scale, which is semi-qualitative, and does not represent the actual surface area of diseased leaf. The objective of this study was to develop a quantitative method of assessing the severity of CMD. A combination of polarimeteric digital colour images, L*a*b* colour model and K-means clustering algorithm were used to determine the areas of CMD symptoms and healthy areas on leaves. The severity of CMD on a leaf is determined by computing the percentage of the CMD symptomatic area to the total leaf area. The analysis provides relatively fast and accurate classification of Cassava mosaic diseased leaves. The proposed method will enable plant scientists to obtain accurate and reliable data, forming the basis for better decision making.
Coherent Imaging of Etched Fission Fragment and Alpha Particles Tracks in a CR-39 SSNTD
We report a set of experimental investigations on the break-up of a liquid drop when falling in a... more We report a set of experimental investigations on the break-up of a liquid drop when falling in a miscible solvent, with the density difference being positive, or negative, or zero. Non-dimensional numbers, derived from the characteristic times of the drop evolution, account for the hydrodynamic instabilities and the self-similar character of the fragmentation process. The role of the initial surface tension at the air-drop interface is explored, leading to scaling laws for the drop volume V and the various height h reached by the drop before it fragments into smaller droplets. From the first break-up to the onset of diffusion, the fragmentation process is shown to have a fractal structure, which is associated to universal power laws for h and V during the dynamical processes associated to the break-up phenomena.
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Papers by Paul Buah-bassuah