Isotopic profiling of natural uranium mined from northern Nigeria for nuclear forensic application.

Four mined samples of natural uranium from northern Nigeria were studied through inductively coupled plasma mass spectrometry, at the Environmental Analytical Chemistry Laboratory, University of the Witwatersrand, Johannesburg. The samples were characterised for lead, thorium and uranium isotopicconcentrations, isotopic ratios and age. The objective was to obtain nuclear forensic fingerprints as baseline data to add to the Nigerian National Nuclear Forensic Library. Results showed significant variation in the isotopic concentrations of lead, thorium and uranium across the mines. Isotopic ratios of 238U/235U, 235U/238U and 234U/238U across the sample of 137.881±0.007, 7.253×10-03±2.05×10-04 and 5.540×10-05±4.08×10-07 were found to be consistent with the natural values. The age of natural uranium is comparable to the age of earth. Uranium, lead, and thorium isotopic concentrations and ratios, as well as the age of the samples characterised, provide an isotopic profile that can be used for nuclear forensic application.Significance:• Given the abundant deposits of natural uranium in Africa and the consequent potential for nuclear insecurity, determining the isotopic profiles and signatures of natural uranium is important for application in nuclear forensics.• Isotopic concentrations of 232Th, 238U, 235U and 234U from the respective sampling sites differed significantly, thereby providing characteristic isotopic profiles

Methods of preparing polyimides and polyimide precursors

Methods of preparing polyimides and polyimide precursors from liquid resins containing tetracarboxylic acid esters and primary diamines which involve spray drying the resin

Polyimide foams

Copolyimide foams derived from a diester of 3,3',4,4'-benzophenonetetracarboxylic acid, an aromatic diamine, and a heterocyclic diamine. A molar concentration of the heterocyclic diamine approaching but not exceeding 0.42 is employed. This results in a flexible foam with a homogeneous cellular structure and a reduced compression set loss

AN EMPIRICAL STUDY OF LEAN AND AGILE INFLUENCES IN SOFTWARE CONFIGURATION MANAGEMENT

Based on a web based survey of 158 IT software development practitioners, mostly from different organizations, this paper examines the application of Software Configuration Management (SCM) process in adaptable software development environments. From the literature review six independent variables and five dependent variables were derived to answer the research question “how does organization size impact on the usage of SCM process in adaptable software development environments?” The six hypotheses confirmed that organization size does not impact on the usage of SCM process in adaptable software development environments. Also, all sizes of organizations consider SCM process valuable and have similar software traceability approaches with different process formalities and tools sophistications. This study helps SCM practitioners to build a better understanding of the relationships between adaptable software development environment, lean principles and practices, and the tools and technologies established to facilitate the coexistence of Agile and SCM practices

Diversification benefits of NFTs for conventional asset investors: Evidence from CoVaR with higher moments and optimal hedge ratios

This study investigates the risk and returns on one of the newest digital asset classes instruments, non-fungible tokens (NFTs), by accounting for tail dependence of higher-order moments and portfolio characteristics. We used a wide range of asset classes, encompassing equites, fixed income securities, and commodities, and document the desirable hedging and portfolio attributes of NFTs by employing Conditional Value-at-Risk (CoVaR) and ∆CoVaRs with various copula functions. We found that NFTs exhibit beneficial investment and hedging attributes under all market conditions, including the Covid-19 pandemic. Our findings have important implications for investors, risk managers, and regulators

Assessment of bonds utilisation in the Nigerian construction industry

Default by contractors in meeting the time and cost performance of a project is usually counterproductive. Considering safety from the high financial burden of construction projects, clients are compelled to seek a level of guarantee in bonds to safeguard them from financial problems and provide incentive for proper and timely completion of the project by the contractor, thereby minimising failures and risks. Therefore, the study assessed the level of bond utilization in Nigerian construction industry, with a view to examining the benefits of its utilisation in construction projects. Survey method was adopted in which questionnaires were used to collect data from respondents. With a response rate of 45.30% (164 of 362), the collected data were analysed using descriptive and analytical scientific method. It was found that the level of bond utilisation in construction contract is high, with performance bond and Advance payment bond being most commonly used construction bond types. Assurance of performance and financial security are the major benefits of bond utilisation. The study recommends that there is need for more enlightenment of construction participants on the various types bond used in construction contract