Outcomes of Planned Organisational Change in the Nigerian Public Sector: Insights from the Nigerian Higher Education Institutions

Conflicting and multiple theories on organisation theory make it complex and therefore present a challenge to public sector administrators and researchers in the public sector. This research shows that government reform agenda did not achieve the desired result in improving the quality and standard of education in Nigerian higher education. There are therefore still gaps in understanding the process of introducing reforms agenda. The result of the in-depth interviews conducted indicated that cultural differences account for organisational values. Thirty one respondents from the five higher institutions in Kwara State, Nigeria and senior officers from the state ministry of education, science and technology believed that a uniform reform agenda would be difficult to implement in all local governments with varying educational needs and levels of educational development. The analysis of the result suggested that culture determines and influences the values of where the institutions are situated. It was discovered that the five institutions have different needs which the society will appreciate if reform agenda focuses on such requirements of the institutions. The paper suggests that the values of the society where an institution is situated should be understood before a reform is formulated. This practice will make the reform easy to implement and reduce the incidence of resistance

Theory of Interplay of Nuclear Magnetism and Superconductivity in AuIn2

The recently reported coexistence of a magnetic order, with the critical temperature T_M=35 \mu*K, and superconductivity, with the critical temperature T_S=207 m*K, in AuIn_2 is studied theoretically. It is shown that superconducting (S) electrons and localized nuclear magnetic moments (LM's) interact dominantly via the contact hyperfine (EX) interaction, giving rise to a spiral (or domain-like) magnetic order in superconducting phase. The electromagnetic interaction between LM's and S electrons is small compared to the EX one giving minor contribution to the formation of the oscillatory magnetic order. In clean samples (l>\xi_0) of AuIn$_2$ the oscillatory magnetic order should produce a line of nodes in the quasiparticle spectrum of S electrons giving rise to the power law behavior. The critical field H_c(T=0) in the coexistence phase is reduced by factor two with respect to its bare value.Comment: 4 pages with 2 PS figures, RevTeX, submitted to Physical Review B - Rapid Communication

INFLUENCE OF THE REORGANIZATION OF ENERGY INFRASTRUCTURE TO AIR POLLUTION IN THE BALTIC STATES

Prognosis of environmental quality in Baltic states related with the closure of Ignalina Nuclear Power Plant according to two electricity production scenarios was made. (Scenario 1 - closure date of Block 1 is 2005, closure date of Block 2 is 2011; Scenario 2 - closure date of Block 1 is 2005, exploitation of Block 2 will be extended at least until 2020.) We can see that in accordance with both scenarios CO2 an SO2 emission will increase every year. Although the influence of the largest air pollution sources such as Estonian/Baltic PP, Lithuanian PP Riga CHP and others remains very significant to the situation in Baltic States, new power plants will forward the rise of total emission

Low processing temperatures explored in Sb2S3 solar cells by close-spaced sublimation and analysis of bulk and interface related defects

This study was funded by the Estonian Research Council project PRG627 “Antimony chalcogenide thin films for next-generation semi-transparent solar cells applicable in electricity producing windows”, the Estonian Research Council project PSG689 “Bismuth Chalcogenide Thin-Film Disruptive Green Solar Technology for Next Generation Photovoltaics”, the Estonian Centre of Excellence project TK141 (TAR16016EK) “Advanced materials and high-technology devices for energy recuperation systems”, and the European Union's Horizon 2020 ERA Chair project 5GSOLAR (grant agreement No. 952509). The article is based upon work from COST Action Research and International Networking project "Emerging Inorganic Chalcogenides for Photovoltaics (RENEW-PV)," CA21148, supported by COST (European Cooperation in Science and Technology); Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD 01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.Antimony trisulfide (Sb2S3) is a promising photovoltaic absorber, which has so far been fabricated mainly by chemical deposition methods. Despite its aptness for congruent sublimation, less research efforts have been made on low-temperature Sb2S3 processing by physical methods. In this regard, recent studies show large variation in the processing temperature of Sb2S3 films, which overall brings into question the need for higher substrate temperatures (>350 °C). Furthermore, in-depth analysis of defect structure of Sb2S3 employing temperature-dependent admittance spectroscopy (TAS) and photoluminescence (PL) remains largely unexplored. In this work, we systematically study the effect of close-spaced sublimation (CSS) substrate temperature on Sb2S3 absorber growth, employing a wide temperature range of 240–400 °C. Temperatures above 320 °C caused cracking phenomena in the Sb2S3 absorber film, proving the unviability of higher processing temperatures. CSS processing temperature of 300 °C was found optimal, producing crack-free Sb2S3 films with increased presence of (hk1) planes, and achieving the best CdS/Sb2S3 device with photoconversion efficiency of 3.8%. TAS study revealed two deep defects with activation energies of 0.32 eV and 0.37 eV. Low-temperature PL measurement revealed a band-to-band emission at 1.72 eV and a broad band peaked at 1.40 eV, which was assigned to a donor-acceptor pair recombination. Temperature-dependent I-V analysis showed that recombination at CdS–Sb2S3 interface remains a large limitation for the device efficiency. --//-- R. Krautmann, N. Spalatu, R. Josepson, R. Nedzinskas, R. Kondrotas, R. Gržibovskis, A. Vembris, M. Krunks, I. Oja Acik, Low processing temperatures explored in Sb2S3 solar cells by close-spaced sublimation and analysis of bulk and interface related defects, Solar Energy Materials and Solar Cells, Volume 251, 2023, 112139, ISSN 0927-0248, https://doi.org/10.1016/j.solmat.2022.112139. (https://www.sciencedirect.com/science/article/pii/S0927024822005566) Published under the CC BY licence.Estonian Research Council project PRG627; Estonian Research Council project PSG689; Estonian Centre of Excellence project TK141 (TAR16016EK); European Union's Horizon 2020 ERA Chair project 5GSOLAR (grant agreement No. 952509; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD 01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

The Palomar Testbed Interferometer Calibrator Catalog

The Palomar Testbed Interferometer (PTI) archive of observations between 1998 and 2005 is examined for objects appropriate for calibration of optical long-baseline interferometer observations - stars that are predictably point-like and single. Approximately 1,400 nights of data on 1,800 objects were examined for this investigation. We compare those observations to an intensively studied object that is a suitable calibrator, HD217014, and statistically compare each candidate calibrator to that object by computing both a Mahalanobis distance and a Principal Component Analysis. Our hypothesis is that the frequency distribution of visibility data associated with calibrator stars differs from non-calibrator stars such as binary stars. Spectroscopic binaries resolved by PTI, objects known to be unsuitable for calibrator use, are similarly tested to establish detection limits of this approach. From this investigation, we find more than 350 observed stars suitable for use as calibrators (with an additional $\approx 140$ being rejected), corresponding to $\gtrsim 95$ sky coverage for PTI. This approach is noteworthy in that it rigorously establishes calibration sources through a traceable, empirical methodology, leveraging the predictions of spectral energy distribution modeling but also verifying it with the rich body of PTI's on-sky observations.Comment: 100 pages, 7 figures, 7 tables; to appear in the May 2008ApJS, v176n

Synthesis Control of Charge Separation at Anatase TiO2 Thin Films Studied by Transient Surface Photovoltage Spectroscopy

For the efficient photocatalytic oxidation of organic pollutants at surfaces of semiconductors, photogenerated holes shall be separated toward the surface and transferred to reactive surface sites, whereas the transfer of photogenerated electrons toward the surface shall be minimized. In this Research Article, the identification of suitable synthesis control of charge separation combined with an in depth understanding of charge kinetics and trapping passivation mechanisms at the related surfaces can provide tremendous opportunities for boosting the photocatalytic performance. In this work, a comprehensive transient surface photovoltage spectroscopy study of charge separation at anatase TiO2 thin films, synthesized by ultrasonic spray pyrolysis from titanium IV isopropoxide TTIP acetylacetone AcacH based precursor is reported. By varying the amount of AcacH in the precursor solution, an experimental approach of synthesis control of the charge transfer toward TiO2 surface is provided for the first time. An increased amount of AcacH in the precursor promotes transition from preferential fast electron to preferential fast hole transfer toward anatase surface, correlating with a strong increase of the photocatalytic decomposition rate of organic pollutants. Suitable mechanisms of AcacH induced passivation of electron traps at TiO2 surfaces are analyzed, providing a new degree of freedom for tailoring the properties of photocatalytic system

The interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons

We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene and ovalene at sub-monolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV and 2.1 eV, respectively. Benzene and naphthalene follow simple first order desorption kinetics while coronene and ovalene exhibit fractional order kinetics owing to the stability of 2-D adsorbate islands up to the desorption temperature. Pre-exponential frequency factors are found to be in the range $10^{14}$-$10^{21} s^{-1}$ as obtained from both Falconer--Madix (isothermal desorption) analysis and Antoine's fit to vapour pressure data. The resulting binding energy per carbon atom of the PAH is $52\pm$5 meV and can be identified with the interlayer cohesive energy of graphite. The resulting cleavage energy of graphite is $61\pm5$~meV/atom which is considerably larger than previously reported experimental values.Comment: 8 pages, 4 figures, 2 table

A post deposition annealing approach for organic residue control in TiO2 and its impact on Sb2Se3 TiO2 device performance

We report a systematic investigation on the influence of two step post deposition treatments PDTs on TiO2 buffer layers deposited by ultrasonic spray pyrolysis USP for emerging Sb2Se3 photovoltaics. Air annealing is a typical method for recrystallizing chemically deposited TiO2 films. However, organic residues such as carbon species from a precursor solution based on titanium tetraisopropoxide and acetylacetone may still remain on the TiO2 surface, therefore requiring an additional annealing step. We demonstrate that vacuum annealing can be a suitable technological approach to decrease the concentration of carbon species in TiO2 films. Vacuum annealing was performed at temperatures at 160 450 C prior to the 450 C air annealing step. It was found that vacuum annealing at 160 C followed by subsequent air annealing led to better device performance. This was explained by achieving an optimal balance between the removal of carbon content during vacuum annealing and the active recrystallization of TiO2 during air annealing. The decrease of carbon concentration by employing the two step approach was supported by changes in the lattice parameters of TiO2 and proven by X ray photoelectron spectroscopy XPS . The given study provides experimental evidence on how nanoscale carbon species in the TiO2 heterojunction partner layer of a Sb2Se3 solar cell can affect the device s performance. By this approach, we generate complementary insights on how the quality of the main interface has an impact and can take a key role despite the optimized Sb2Se3 grain structure and orientatio

Discovery of a Be/X-ray Binary Consistent with the Position of GRO J2058+42

GRO J2058+42 is a 195 s transient X-ray pulsar discovered in 1995 with BATSE. In 1996, RXTE located GRO J2058+42 to a 90% confidence error circle with a 4' radius. On 20 February 2004, the region including the error circle was observed with Chandra ACIS-I. No X-ray sources were detected within the error circle, however, 2 faint sources were detected in the ACIS-I field-of-view. We obtained optical observations of the brightest object, CXOU J205847.5+414637, that had about 64 X-ray counts and was just 0.3' outside the error circle. The optical spectrum contained a strong H alpha line and corresponds to an infrared object in the 2MASS catalog, indicating a Be/X-ray binary system. Pulsations were not detected in the Chandra observations, but similar flux variations and distance estimates suggest that CXOU J205847.5+414637 and GRO J2058+42 are the same object. We present results from the Chandra observation, optical observations, new and previously unreported RXTE observations, and a reanalysis of a ROSAT observation.Comment: 18 pages, 6 figures, Accepted for publication in the Astrophysical Journa

Analysis of grain orientation and defects in Sb2Se3 solar cells fabricated by close spaced sublimation

The performance of a superstrate TiO2 Sb2Se3 solar cell, fabricated by close spaced sublimation technique CSS , was improved after the deployment of a seed layer. The seed layer caused columnar Sb2Se3 film growth with texture coefficient analysis TC showing increased presence of crystal planes, which are inclined towards the [001] crystal direction. Given the highly anisotropic properties of Sb2Se3, preferential growth of Sb4Se6 n rib bons along the [001] direction is best suited for effective charge collection. Hence, grain orientation of Sb2Se3 films was studied more closely via measurement of pole figures by XRD and orientation distribution maps by electron backscatter diffraction EBSD . Although the measurements did not reveal strong preferred orientation, it was observed that the columnar Sb2Se3 growth enhanced texture along the [001] direction. Temperature dependent admittance spectroscopy TAS and capacitance voltage CV profiling were performed on the seed assisted TiO2 Sb2Se3 solar cell to evaluate carrier density and deep defects in the Sb2Se3 absorber. TAS study revealed a deep defect with activation energy of 0.39 eV. CV profiles indicated that the density of defects could be as high as 1017 c