We employ density functional theory (DFT) to investigate how Stone-Wales (SW) defects modulate the electronic and electrochemical properties of two-dimensional silicon carbide (SiC) monolayer for sodium (Na)-, potassium (K)-, and magnesium (Mg)-ion batteries. The SW-SiC structure is energetically feasible and dynamically stable, with defect formation reducing the bandgap by ~ 70% and enhancing electronic conductivity. Compared to pristine SiC, SW-SiC exhibits stronger adsorption for Na (- 0.89 eV) and K (- 1.52 eV) with pronounced charge transfer at the adatom-substrate interface. Theoretical capacities of 300 and 600 mAh g⁻1 for Na and K, respectively, are achieved, along with low diffusion barriers (0.88 eV for Na, 0.54 eV for K) and favorable open-circuit voltages (0.44 V, 0.70 V). Minimal structural distortion upon ion insertion confirms structural stability. These results elucidate the defect-property interplay in 2D SiC and establish SW defect engineering as a viable approach for optimizing condensed-phase anode materials beyond lithium systems.

In this study, density functional theory (DFT) is employed to investigate how the introduction of Stone–Wales (SW) topological defects can modify the structural, electronic, and electrochemical properties of monolayer silicon carbide (SiC) for sodium (Na) ion storage. Results show that SW-defective SiC (SiC-SW) is both energetically feasible and dynamically stable, with enhanced electronic conductivity compared to pristine SiC. Na adsorption energy improves from 0.85 eV (pristine) to – 0.89 eV (SiC-SW), while the diffusion barrier remains low (0.88 eV). SiC-SW achieves a maximum Na storage capacity of 300 mAh g⁻¹ with an average open circuit voltage (OCV) of 0.44 V. These findings suggest that SW defect engineering could make SiC a competitive anode material for next-generation Na-ion batteries

We constructed SiC/borophene heterostructure based on the method of commensurate lattice with supercell approach and studied the structural, electronic and electrochemical properties using density functional theory (DFT). The interfacial binding energy of SiC/borophene is as high as -26.07 meV/& Aring;2. Significant amounts of charge were found to drift from SiC to borophene, resulting in interfacial charge redistribution and increased Li binding affinity on the surfaces. The electronic properties of SiC/borophene showed pronounced metallic conductivity, a trait conducive to anodic applications in electrochemical cells. The calculated Li adsorption energy at the interface of SiC/borophene is -2.23 eV. Multiple layer adsorption is also observed, with the heterostructure retaining much of its structural integrity after adatom adsorption, indicating possible good cycling stability. At the maximum concentration, the Li storage capacity for SiC/borophene is 1980.63 mAh/g, surpassing a large variety of other reported 2D complexes. Also, an overall average operating voltage of 1.06 V is maintained in the structure, which is in proximity of the optimal 1.5 V threshold requisite for anodic operations. The diffusion energy barriers associated with lithium ion migration across the three distinct adsorption sites of the heterostructure all reveal a nominal magnitude with the lowest barrier energy of 0.54 eV at the top of borophene adsorption layer and site. These findings show that SiC/borophene could be used as an anode in very highcapacity lithium-ion batteries.

This study delves into the structural and electronic effects of oxygen vacancies in Cu2O using density functional theory (DFT) enhanced with Hubbard U corrections (DFT+U). A 3x2x1 supercell of Cu2O was employed. The study meticulously investigates the removal of 1, 2, and 3 oxygen atoms, analyzing the ensuing changes in both structural stability and electronic properties, with particular emphasis on the band gap.The structural analysis revealed that oxygen vacancy formation induces significant modifications in Cu-O and Cu-Cu bond lengths, with elongations observed around the vacancy sites in which the Cu-Cu bond length decreased to 2.4035 Å, compared to 3.0066 Å in the pristine structure. The structural distortion followed the Jahn-Teller effect, leading to the formation of isolated units and transformation in bond angles. The introduction of oxygen vacancies without replacement (WOR) caused significant distortions in the Cu2O lattice, which were more pronounced with increasing vacancy concentration. The Cu-O bond length increased from 1.8492 Å in the pristine structure to 1.9840 Å in the single vacancy configuration. However, in the oxygen vacancies with replacement (WR) the Cu-Cu bond length increased slightly to 3.0218 Å, with the Cu-O bond length expanding to 1.8505 Å. The band structure analysis indicated a decrease in the band gap with increasing vacancy concentration. The pristine Cu2O exhibited a band gap of 1.67 eV as calculated, which was increased to 1.97 eV with a single vacancy and 1.16 eV with two vacancies, reflecting the significant impact of oxygen vacancies on the material’s optoelectronic properties. The findings underscore the critical role of oxygen vacancies in modulating the structural and electronic properties of Cu2O, providing insights that are pivotal for optimizing its performance in applications like photocatalysis and solar cells.

This study utilizes Density Functional Theory (DFT) within the Quantum ESPRESSO framework to explore the effects of oxygen vacancies and nitrogen doping on the electronic structure and optical properties of cuprous oxide (Cu2O). Pristine Cu2O, an intrinsic p-type semiconductor, typically exhibits a direct band gap. Introducing an oxygen vacancy in the absence of a dopant broadens the band structure, leading to both direct and indirect band gap characteristics. In contrast, nitrogen doping transforms the band gap into a direct one, significantly reducing it from 1.97 eV to 1.09 eV, which deviates from previous findings due to potential variations in the initial state of the Cu2O host crystal. Furthermore, spin-polarization effects indicate spin-dependent behaviour within the material. The study also examines the absorption properties of pristine, defective, and nitrogen-doped Cu2O systems using the complex dielectric function. The results show distinct absorption peaks and transitions, with nitrogen-doped Cu2O exhibiting strong absorption in the visible light range, underscoring its potential for solar cell applications.

Radon exposure through ingestion or inhalation from groundwater can be a significant public health concern due to its carcinogenic effects. This study assessed the health risks of radon exposure from groundwater in Lapai, Nigeria, using a Rad7 detector to measure radon concentration levels. The measured concentrations ranged from 5.36 ± 0.22 BqL-1 to 0.52 ± 0.06 BqL-1 with an average value of 2.82 ± 0.14 BqL-1. The annual effect dose due to ingestion of Radon obtained varies in the range of 2.76 to 28.34 μSva-1, 1.02 to 10.43 μSva-1, and 1.33 to 13.69 μSva-1 for infants, children, and adults, respectively. While the effective dose per year from inhalation of Radon released from water by adults has values in the range of 1.31 to 13.50 μSva-1. Radon levels were within permissible limits of UNSCEAR and USEPA, and the annual effective doses from inhalation and ingestion were within WHO's safe range. Nonetheless, monitoring is advised, especially during the rainy season when contamination levels may increase.

This study investigates the structural and electronic properties of defected Cu2O using density functional theory (DFT) within the Quantum Espresso package, incorporating plane wave and pseudopotential methods. The analysis includes three exchange-correlation functionals: Perdew-Burke-Ernzerhof (PBE), Perdew-Burke-Ernzerhof revised for solids (PBEsol), and local density approximation (LDA), with and without the Hubbard term (U=8.5 eV for Cu and O). The study reveals that PBE and PBEsol underestimate the experimental lattice constant 'b' while PZ-LDA provides values closer to the experimental data. The lattice parameters for PBEsol (b = 7.6940 Å) and PZ-LDA (b = 7.7006 Å) were observed to deviate from the initial lattice parameter (b = 8.5040 Å). Bond distances, such as Cu-O and O-O, are overestimated across all functionals, with PBE yielding the highest values (Cu-O = 1.9082 Å, O-O = 3.8027 Å) compared to PZ-LDA (Cu-O = 1.9077 Å, O-O = 3.8018 Å) and PBEsol (Cu-O = 1.8652 Å, O-O = 3.7406 Å). The Cu-Cu bond distance showed a modulated pattern with LDA underestimating these values (Cu-Cu = 3.1776 Å). Bond angles in the structure also varied, with angles such as Cu5∠O11∠Cu6, Cu5∠O11∠Cu7, and Cu6∠O11∠Cu7 showing significant deviations across functionals. The inter-atomic distances at the vacant site also exhibited noticeable changes post-relaxation, particularly with PBEsol and LDA, where the distances between Cu atoms such as Cu11 to Cu21 (2.4855 Å), Cu06 to Cu16 (2.4855 Å), and Cu06 to Cu11 (2.6653 Å) differed from the initial values (3.006 Å). The inclusion of the Hubbard term notably impacted the band structure, improving the band gap values for all functionals. The Fermi energy (eV) for PBE (1.97 eV), PBEsol (1.05 eV), and LDA (1.27 eV) showed varied deviations. The study highlights the Jahn-Teller distortion effect, particularly at the Cu-Cu bond length at the oxygen vacant site, and underscores the importance of Cu 3dxz, 3dyz, and O 2s orbital hybridization in forming the defected Cu2O band gap. The research therefore, underscores the necessity of accounting for exchange-correlation effects and the Hubbard term in accurately modeling defected Cu2O, contributing to a deeper understanding of its electronic properties and guiding future doping investigations.

This study presents a broad reactor physics analysis including, neutronic, burnup, and decay heat of the 'as-built' NIRR-1 LEU core performed using SCALE 6.2.3 code package. First, verification of neutronic parameters of the NIRR-1 was performed by modeling the reactor 'as-built' LEU core. Thereafter validation of the model was done by comparing calculated result with measured data during the commissioning of the reactor. The results showed that the estimated neutronic parameters using KENO-VI code of SCALE 6.2.3 code package are in close agree-ment with the measured data. Hence, KENO-VI can be used for detailed neutronic assessment of MNSRs. The total decay heat at the end of core life after operation for 216 EFPD was estimated to be 1620.15 W and was majorly due to the contribution from fission products which was estimated to be 1608.10 W. This value explains why MNSRs are cooled through natural convection of the coolant during operation and at shutdown conditions. Additionally, the burnup of the core was determined to be 0.53 wt% which is within the expected burnup for a typical MNSRs (less than1 wt%) with a core lifetime of about 200 EFPD (similar to 10 years). Furthermore, the mass of 239Pu buildup after 216 EFPD was far less than the IAEA category III nuclear material and indicates a huge advantage of research reactor conversion in reducing proliferation risk.

This paper investigated the feasibility of developing alternative insulating nanofluid from a mixture of Jatropha and Neem oils into which compositions of 0.2 to 1.0 wt% of titanium oxide nanoparticles were dispersed. FTIR, SEM–EDX and XRD analyses of titanium oxide nanoparticles were carried out. The DC and AC breakdown voltages were measured and analysed using Weibull statistical tool. In the Weibull statistical analysis, it was observed that the characteristic breakdown field strength of PJO is higher relative to PNO and has slight differences compared to the PJNO sample. With the dispersion of TiO2 nanoparticles, the characteristic breakdown strength improved as compared with the base oil. Furthermore, the developed Jatropha–Neem mixture nanofluid recorded characteristic breakdown field strength that is much higher compared to that of the mineral oil sample. The mixture of Jatropha and Neem oil nanofluid sample possessed the highest characteristic breakdown strength among prepared nanofluids which indicates that the characteristic breakdown strength of the oil samples has been improved considerably with the dispersion of TiO2 nanoparticles. The results have shown the viability of Jatropha–Neem nanofluid as insulating oil for use in oil-filled power equipment.

In spite of the acceptability and production of Uranium Oxides (UO2) with Low Uranium Enrichment (LEU-UO2) fuel in commercial scale, the use of uranium–silicide (U–Si) in place of the UO2 is one of the promising concepts being proposed to increase the accident tolerance of nuclear fuels. In this study, SCALE 6.2.3 computational tools have been used to model the Nigerian Research Reactor-1 (NIRR-1) which is a typical Miniature Neutron Source Reactor (MNSR) and calculated the core neutronic parameters such as Clean Core Cold Excess Reactivity (CCER), Control Rod Worth (CRW), Shutdown Margin (SDM), Safety Reactivity Factor (SRF) and Neutron flux distribution for the Highly Enriched Uranium (HEU) and candidates LEU cores. The results showed a close agreement between the calculated and measured data. The bias between calculated and measured data was attributed to the computational limitation of this study that was caused by a limited number of particles histories used in criticality calculations. The neutronic performance of the U3Si2–Al, U3Si–Al and U9Mo–Al fuels indicated the suitability of these candidates LEU fuels for conversion of MNSRs from HEU to LEU. The observed reduction in the thermal flux of the candidate LEU fuels was attributed to higher inventory of U-238 in LEU fuels when compared with the HEU and further underscore the need to raise their thermal power by approximately 10% for efficient utilization of the MNSR in Neutron Activation Analysis.

The study was conducted to investigate the influence of feeding some of the common browse trees leaves in Bauchi state on haematological and biochemical parameters of Yankasa lambs. Fourty lambs were allotted to eight different browse trees namely: Maje (Daniella oliver), Madaci (Khaya senegalensis), Marke (Anogesisessus leicarpus), Baure (Ficus syncomorus), Kuka (Adansonia gigitata), Magarya (Zizaphus Mauritania), Taura (Detarium macrocarpum) and Baushe (Terminalia glaucescens), as treatments with five replications in each case. The feeding trial lasted for seventy days. Ten milligrams (10mls) of Blood sample was collected from each animal at the end of the feeding trial. The samples were collected via Jugular vein early in the morning. About 3mls of each blood sample was placed in EDTA (anticoagulant) bottle for haematological studies. The haematological values obtained from lab were subjected to statistical analysis. The remaining 7mls was placed in universal bottle and allowed to stand at room temperature and centrifuged for 15 minutes. The serum was separated and store in a freezer for chemical analysis. The hematological values obtained from lab were subjected to statistical analysis. Results indicated Taura had significantly higher (p<0.05) PCV (40.70 %) and MCV (64.60 pl), Magarya Hb (13.66 g/dl) and RBC (8.48 X1012 ) Maje MCH (19.24 pg) values. Baure and Maje were higher (p<0.05) with statistically the same values of 7.22, respectively in RBC. WBC was highest in Marke leaves (10.5 X109) while Maje recorded significantly highest (p<0.05) MCHC value of 37.74 g/dl. Blood serum showed that there was no significant difference (p>0.05) in Urea concentration across all the treatments. Animals fed Madaci recorded the highest Total protein value of 7.4 g/l. Conclusively, Madaci had the highest PCV, Hb and MCH and total protein but, no significant difference in urea across the treatments L'étude a été menée pour étudier l'influence de l'alimentation de certaines des feuilles d'arbres de 'browse' dans l'état de Bauchi sur les paramètres hématologiques et biochimiques des agneaux Yankasa. Quarante agneaux ont été attribués à huit arbres de browse différents, à savoir : Maje (Daniella oliver), Madaci (Khaya senegalensis), Marke (Anogesisessus leicarpus), Baure (Ficus syncomorus), Kuka (Adansoni agigitata), Magarya (Zizaphus Mauritania), Taura (Detarium macrocarpum) et Baushe (Terminalia glaucescens), en tant que traitements avec cinq répétitions dans chaque cas. L'essai d'alimentation a duré soixante-dix jours. Dix milligrammes (10 ml) d'échantillon de sang ont été prélevés sur chaque animal à la fin de l'essai d'alimentation. Les échantillons ont été prélevés par veine jugulaire tôt le matin. Environ 3 ml de chaque échantillon de sang ont été placés dans un flacon 'EDTA' (anticoagulant) pour les études hématologiques. Les valeurs hématologiques obtenues en laboratoire ont été soumises à une analyse statistique. Les 7 ml restants ont été placés dans une bouteille universelle et laissés au repos à température ambiante et centrifugés pendant 15 minutes. Le sérum a été séparé et stocké dans un congélateur pour l'analyse chimique. Les valeurs hématologiques obtenues en laboratoire ont été soumises à une analyse statistique. Les résultats ont indiqué que Taura avait des valeurs significativement plus élevées (p <0,05) le 'PCV' (40,70%) et le'MCV' (64,60 pl), Magarya Hb (13,66 g / dl) et le 'RBC' (8,48 X1012) Maje MCH (19,24 pg). Baure et Maje étaient plus élevées (p <0,05) avec statistiquement les mêmes valeurs de 7,22, respectivement en RBC. Le WBC était le plus élevé dans les feuilles de Marke (10,5 X109) tandis que Maje a enregistré la valeur ''MCHC significativement la plus élevée (p <0,05) de 37,74 g / dl. Le sérum sanguin a montré qu'il n'y avait pas de différence significative (p> 0,05) dans la concentration d'urée dans tous les traitements. Les animaux nourris au Madaci ont enregistré la valeur protéique totale la plus élevée de 7,4 g / l. En conclusion, Madaci avait les plus hauts 'PCV', 'Hb', 'MCH' et protéines totales, mais aucune différence significative d'urée entre les traitements.

Tropospheric radio wave signals experience loss due to multipath effect, scattering and other forms of attenuation through the atmospheric medium, primarily due to variations in weather conditions with time. The knowledge of surface refractivity profile is important for optimal planning of Very High Frequency/Ultra High Frequency (VHF/UHF) terrestrial radio links in a region. The study of surface refractivity (Ns) over the North-Central Nigeria was carried out using meteorological data from seven locations in North-Central zone of Nigeria. The seasonal variations of Ns were also derived using the monthly summaries of surface data obtained from Nigerian Meteorological Agency (NIMET) over seven stations of Abuja, Lafia, Lokoja, Makurdi, Jos, Minna and Ilorin between 2005 and 2010.The results indicated that the monthly averages of radio refractivity during the rainy season months (April to October) are greater than the Ns values during the dry season months (November to March) for all the locations throughout the years of the study. The computed of mean monthly Ns over all the seven stations in the first 1 km above the ground level is 348 N-units, which gives mean refractivity gradient (dN/dh) of -49 N/k, these shows that the region is characterised by low scale super-refraction. The mean k-factor over the entire region in the first 1 km above the ground level is 1.4; the mean Field Strength Variability (FSV) in first 1 km of height in the region was calculated to be 14 dB. The mean Radio Horizon distance within 1 km height for a transmitter height of 100 m over the stations is 42 km. The results provide useful information needed by radio engineers to set up new terrestrial radio propagation links or to improve on the existing ones especially at VHF, UHF in the North-Central region of Nigeria, as recommended by International Telecommunication Union Recommendations (ITU-R P.453, 2013), which observed the need for local reference data on refractivity and refractivity gradients all over the world.

Department of Physics, Faculty of Physical Sciences, Ahmadu Bello University, Zaria Department of Applied Sciences, College of Science and Technology Kaduna Polytechnic, Kaduna *Corresponding Author’s Email: ahmedmohammed7984@gmail.com ABSTRACT Contamination from municipal waste can increase the natural levels of heavy metals in soil, creating a health hazard to public and the environment. Environmental samples from the residential dumpsite were analyzed to determine the content and concentrations of va elements in six soil plumes taken at different depths: 0, 25, 50, 100, 120 and 150 cm respectively from the top layer down the soil profiles. The instrumental neutron activation analysis (INAA) technique was employed in the study. The analysis result nine elements comprising of heavy metals, reference and radioactive elements. Further analysis indicates a fluctuation in concentration of the elements down the profile and predicted elements exhibits a strong positive correlation amongst in concentrations of some elements in the middle of the sample follows the order Mg Na Fe K Al. The results show that despite slow absorption reaction of the metal within the middle of the sample, these metals displayed a uniform distribution within the specific soil matrix.

The physical properties of briquettes made from rice husk and coconut shell in different ratios were evaluated based on their thermo-physical properties. The calculated calorific values of the rice husk and coconuts hell are 16.51 MJ/kg and 18.60 MJ/kg, with densities of 1.50 g/cm3 and 3.00 g/cm3, respectively. Coconut shell has lower moisture and ash content of 10% and 26%, respectively, before briquetting. Comparisons of the experimental and calculated calorific values of the briquettes (17 to 21 MJ/kg) showed that they are in agreement with those of the American Standard of Testing Materials (ASTM) and those reported in the literature. The results further showed that the calorific values of the five briquette ratios were not a function of their moisture and ash contents, rather their total carbon contents. The briquette at the ratio 90:10 of rice husk to coconut shell has the highest calorific value and implies that it has more heating advantages and will therefore be suitable as an alternative solid fuel.

The quest for improved polymeric insulation to achieve a compact and reliable electrical and electronic power equipment design brings about the idea of composite polymeric insulation. Emphasis has been on chemically synthesised metal oxide nanoparticles. This paper presents the dielectric behaviour of epoxy polymer composite with microparticles with an average particle size of about 4.3 mu m from the periwinkle shell. The changes in the relative permittivity and dielectric loss of the polymer with the periwinkle shell composite metal oxides at low filler concentrations were studied over a frequency range from 200 Hz to 100 kHz. The results showed that the polymer composite exhibits dielectric characteristics that are quite different when compared with the earlier observed results for polymer micro-composites. Unlike the usual expectations of increasing dielectric loss with increasing filler concentration in polymer micro-composites, the dielectric response of the epoxy-shell microparticle powder composite displayed a decrease in the dielectric loss with micro-filler concentration. The 1 wt% periwinkle shell microparticle epoxy composite has a dielectric loss lower than that of 0.5 wt% Al2O3 nanoparticle epoxy composite. This suggests that the waste periwinkle shell can serve as a cheap resource to produce low-cost polymer composite with improved electrical insulation properties.

Detector efficiency calibration is mandatory for accurate measurement of induced activity in irradiated samples and for safe operation of the reactor with minimal uncertainty. This paper reported the efficiency calibration of vertically dIpstick High Purity Germanium detector, installed at the Centre for Energy Research and Training, Ahmadu Bello University Zaria for the purpose of large sample Neutron Activation Analysis (NAA) using Nigeria research reactor-1 (NIRR-1). The performance of the detector was evaluated for the radioisotope activity measurements during the reactor operation for large samples neutron activation analysis. The detector performance in terms of radioisotopes detection ability was inspected using the standard conventional and semi-empirical approaches. The full energy peak efficiencies were determined at the corresponding energies for three different geometries (source to detector distance of 1, 5 and 10 cm). The semi-empirical approach produced better and precise results that logically rhymed with theory than the traditional approach. Besides that, a consistency in the nature of the graphs and values were evidenced. The determined efficiencies and their corresponding energies revealed encouraging outcome and ensured the successful NAA for large samples of different material compositions.

A preliminary study which aimed to establish a reference data on naturally occurring radioactive materials (NORMs) for River Yobe has been conducted. Soil and sediment samples were collected along the coastal areas of the river and analyzed to determine the specific activities of NORMs such as 238U, 232Th and 40K. Gamma spectrometry technique using NaI (Tl) detector was employed to determine the specific activities f the natural radionuclides. The mean activity concentration in the soil samples for 238U, 232Th and 40K were found to be 23±1.5, 36±2.5 and 395±9.1Bq kg−1 and for the sediment samples are 60±2.6, 45±3.6 and 324±6.8Bq kg−1 respectively. These values, in some cases exceed the world reference values of 30, 35 and 400 Bq kg−1 for 238U, 232Th and 40K respectively. Parameters of radiological hazard, were also estimated based on specific activity of the radionuclides to assess the radiological impacts due to exposure on the users of the river. The results were found to be within the worldwide recommended safety limits.Keywords: Annual effective dose, NORMs,238U.232Th.40K. River Yobe

Vegetable oil with high percentage unsaturated fatty acid content are unstable to oxidation at elevated temperatures. However, epoxidation is an effective chemical reaction for chemical structural modification of such oil to eliminate unsaturated carbon-carbon double bond which is responsible for the instability of the oil. In this research, laboratory purified neem oil was epoxidized in situ in the presence of an acidic catalyst and the product was further transesterified. The purified (PNO), epoxidized (ENO) and transesterified (ENOE) oil samples produced were characterized by FTIR, Viscosity measurement using Brookfield Digital Viscometer, relative permittivity, loss tangent and ac conductivity measurements were made using a coaxial probe placed in a thermostatically controlled heat chamber and a frequency analyzer at varying frequency and temperature in the range 20 Hz to 20 kHz and 20 degrees C to 70 degrees C respectively. All three samples show Arrhenius type behavior for viscosity and ac conductivity. ENOE sample had least viscosity of 0.0254 Pa s at 40 degrees C. Both PNO and ENO had a.c conductivity of the order 10(-10) S/m at 20 degrees C and power frequency and loss tangent of 0.0082 and 0.0191 respectively. The oil samples possess low loss in the temperature and frequency ranges considered and are suggested to be suitable candidate for potential natural ester insulating fluid in High Voltage equipment.

Polycrystalline BaTiO 3 and Ba(Ti 0.96 SnxZr 0.04-x )O 3 ceramics (x = 0.02-0.04) were prepared by a combination of solid-state and mechanochemical process and characterized at room temperature by X-ray diffraction for phase composition. Their crystal structures were found to be of the cubic and tetragonal symmetries, respectively. The grain size and porosity which were determined using Field Emission Scanning Electron Microscope (FESEM) and densi- tometer, respectively showed decrease and increase of relative density respectively, with increase in doping concentration. The variations of dielectric constant and loss with fre- quency and temperature show a maximum dielectric constant of 1660 at room temperature for Ba(Ti 0.96 Sn 0.03 Zr 0.01 )O 3 . The remnant polarization (P r ) and coercive field (E c ) of BT were found to be 581.73 V/cm and 0.27 μ C/cm 2 . Increase in Sn content led to an increase in Pr of 0.58, 3.07, 3.73 C/cm 2 , and Ec of 1766.8, 2855.7, 2661.1 V/cm, respectively and are expected to lead to a significant reduction in the thickness of the multilayer ceramic capacitors. Imped- ance spectroscopy of polycrystalline Ba (Ti 0.96 Sn 0.02 Zr 0.02 ) O 3 in a wide frequency and temperature range showed Nyquist plots with presence of grain and grain boundary at 400 (cid:1) C and a negative temperature coefficient of resistance (NTCR) for Ba(Ti 0.96 Sn 0.02 Zr 0.02 )O 3 . The dielectric relaxation showed a non-Debye character.

The Nigeria Research Reactor-1 (NIRR-1) is one of the Commercial Miniature Neutron Source Reactors (MNSRs) sited outside China and scheduled for conversion under the auspices of Reduced Enrichment for Research and Test Reactors (RERTR) program. Since 2006, the reduction in the fuel enrichment of MSNR facilities from greater than 90% HEU cores to less than 20% LEU cores has been embarked upon. Consequently in this work, the physics parameters of three dispersion LEU fuels, which include U3Si, U3Si2, and U9Mo enriched to 19.75% were determined by the MCNP code to investigate their suitability for the conversion of NIRR-1 to LEU. The following reactor core physics parameters were computed for the LEU fuel options: clean cold core excess reactivity (ρex), control rod (CR) worth, shut down margin (SDM), neutron flux distributions in the irradiation channels and kinetics data (i.e. effective delayed neutron fraction, βeff and prompt neutron lifetime, lf). Results are compared with experimental and calculated data of the current HEU core and indicate that it would be feasible to use any of the LEU options for the conversion of commercial MNSR in general and NIRR-1 in particular from HEU to LEU.