Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality.Consequently, robust methods with potential to remove various types of hazardous elements are required.Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge.Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process.The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra.The results show that Cr (VI) is not stable in strong nitric acid solutions.Reduction of Cr (VI) species decreased with decreasing temperature, NO 2 concentration, ionic strength and absence of light.These findings support the proposed reduction reaction: ( ) ( ) 2 2 7 2 Cr O aq 6NO 2H aq -+ + + → ( ) ( ) 3 2 3 2Cr aq H O 6NO aq .+ -2 1 3 2 3 2 Rate Cr III k HNO Cr VI k k H O ⋅ ⋅ + ⋅ ∝ .
Introduction: The Six Sigma methodology is an opportunity for a better understanding of the performance of analytical methods and for a better adaptation of the quality control management policy of the medical biology laboratory. Using the sigma metric, this study assessed the performance of the Biochemistry analytical system of a medical biology laboratory in Côte d'Ivoire. Methods: Six Sigma methodology was applied to 3 analytes (alanine aminotransferase, glucose and creatinine). Performance indicators such as measurement imprecision and bias were determined based on the results of internal and external quality controls. The sigma number was calculated using the total allowable error values proposed by Ricos et al. Results: For both control levels, ALT had a sigma number greater than 6 (7.6 for normal control and 7.9 for pathological control). However, low sigma numbers, less than or equal to 2 for creatinine (1.4 for normal control and 2 for pathological control) and less than 1 for glucose were found. Conclusion: This study revealed good analytical performance of ALT from the point of view of 6 sigma analysis. However, modifications to the overall quality control procedure for glucose and creatinine are needed to improve their analytical performance. The study should be extended to the entire laboratory’s analytes in order to modify the strategies of quality control procedures based on metric analysis for an overall improvement in analytical performance.
A problem in chemical analysis in connection with measurements of a substance normally occurring in a sample, or identification of a substance which should not exist in a sample, is insufficient selectivity.In this article, we analyze this problem and propose remedies.We use a real doping case to illustrate how chemical noise causes a serious selectivity problem, probably causing a false positive outcome.
The application of vibrational spectroscopy in the pharmaceutical industry is widely investigated, from the quality assurance of the product during the production process control to the final products' quality control and the authentication of products on the markets.This study focuses on non-contact and noninvasive detection and identification of pain-relievers at 1 -5 meters standoff distances.The specimens analyzed include standard laboratorygrade active ingredients and commercially available pain relievers in powder, solid and liquid forms.All the remote measurements captured revealed the Raman signatures of the specimens, with varying peak intensities.To correlate the band intensities captured with the standoff distances between the laser source and the specimens, the intensity ratios of the two prominent peaks of the laboratory grade reference active ingredient (1607 and 1319 cm -1 ) normalized with 1319 cm -1 are used.The results of the study suggest the viability of standoff Raman spectroscopy for routine monitoring and identification of pharma-ceuticals, including counterfeit pain relievers.
The main aim of this project was to come up with an efficient method for the purification of graphite to at least 99%. There has been an increasing demand for high-grade graphite products with up to 99.99% carbon that has resulted in the development of various approaches to remove impurities even to parts per million range. Removal of impurities from 94% graphite is important to achieve a high-purity graphite product. Microwave irradiation was used to prepare high-purity graphite from 94% graphite concentrate. The results showed that microwave irradiation could enhance the fixed carbon of flake graphite to a higher level. Under the optimum conditions selected of 4 minutes’ reaction time and 100% microwave output (800 W), a graphite product with a fixed carbon content of 98.845% was obtained from flake graphite concentrate. According to XRD, FTIR and Handheld XRF analysis, impurities mainly composed of Fe, Co, Sr and Zr were present before treatment. After treatment under optimum conditions Fe, which was the major impurity in the sample was reduced from 3.566% to 1.031%. The ash content of graphite under optimum conditions was 1.55%. The crystal structure of flake graphite showed no change. It can be concluded from this study that graphite purification using microwave irradiation increases the carbon content of graphite.
Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown the presence of an unknown low molecular weight species, deemed to be a “Conthiol”, which could be important in this respect. This was prepared and isolated from a human prostate cancer cell line (LNCaP) in the form of an adduct of 2-mercuri-4-nitrophenol; it accounts for 56.5% of the total cellular thiols present in this cell line. Initial LC-MS analysis of this adduct had indicated that the possible molecular weight of the thiol was in the region of 467 daltons. In further analytical studies to identify the thiol, attempts were made to release it from the adduct by passage through a Thiopropyl Sepharose6B column. LC-MS analysis of the column eluate revealed two components yielding negative ion fragments of 427 m/z and 449 m/z. Only the former component contained thiol, indicating that a breakdown and/or possible rearrangement of the Conthiol had occurred. Further investigations of the column thiol eluate using ICP-MS analysis showed that the sulfur content agreed with the spectrophotometric analysis result (Ellman assay) and that the molecule did not contain phosphate. Amino acid analyses of the eluate were negative. In an attempt to prevent the breakdown of the thiol released by the Thiopropyl Sepharose 6B column, the adduct was treated with 5% v/v bromine water prior to applying to the column. In this instance the thiol containing eluate obtained from the column was treated with an equimolar quantity of mercuric chloride forming a fresh adduct, RS-Hg-SR. LC-MS analysis of this mercurial adduct detected a negative ion fragment of 782 m/z which on further ionization gave a ladder like pattern showing loss of mass units of 58 in each rung. This would seem to suggest the presence of a repeat polymer like structure containing 5 monomers, which, plus the thiol atom, gives a possible formula weight of 322; probably revealing only a part of the unknown Conthiol molecule whose properties and formula weight do not correlate with any known cellular thiol. Further analysis of the thiol released from the adduct on the Thiopropyl Sepharose 6B column by Infra-red (FTIR) provided little information except to confirm the presence of the thiol group and C=O stretch bands together with the possibility of a lactam ring at 1651 and 1634 cm·sǃ.
The Schr?dinger differential equation is what we usually solve for the microscopic particles in non-relativistic quantum mechanics. Niels Bohr suggested the power two of the (usually) complex answer shows the probability of the particle’s existence at a point of space. Also, the time dependence of Schrodinger wave equation is one whereas for light in electromagnetism is two. In this paper, we show a solution for both problems. We derive a Wave Equation for the energy of every system. This electromagnetic wave equation is shown to convert to those classical (i.e. the Schrodinger) and special relativistic (i.e. Klein-Gordon) quantum mechanical equations. Also, accordingly there definitely is a physical meaning to answer to this wave equation. And therefore, switching the probabilistic interpretation of quantum mechanics to a deterministic one as (Albert) Einstein demanded.
This project investigated the potential optimal development strategy for a saturated reservoir, with a gas cap.It assessed the viability of three production methods-solution gas drive (primary depletion), water flooding and gas injection, using varying injector well numbers.This project also undertook sensitivity analysis in the field, concluding that the development of another appraisal well would vastly improve the accuracy of NPV calculation.Furthermore, this project ascertained an optimized recovery method, based on numerical production simulations and economic modelling, of initial solution gas drive recovery, until reservoir pressure equals the bubble point pressure, at which point three water flooding injectors should be employed, developed at six-month intervals to maximise production while limiting CAPEX and OPEX as much as possible.
Honey bees derive their nutrients from nectars and other plant materials. These naturally available materials are affected by the residual presence of pesticides. The concentration of pesticides in honey comb then reflects the leftover after degradation. In this study, samples of honey were collected from five different farms in Plateau State and analyzed for pesticide residues (atrazine, cypermethrin) and heavy metals (Pb, Cd, Cr, Fe and Mn) using GC-MS and AAS techniques. Results of the analysis indicated that atrazine and cypermethrin were found in the range (0.01 - 0.36 and 0.11 - 0.26) mg/kg, respectively in all the samples. Mn and Fe were found across the samples while Cd was detected only in the sample obtained from Maraban Jos (0.0013 mg/kg). Except Bokkos and Maraban Jos, Pb was detected in other samples. This study revealed that all samples contained the selected pesticide residues above the maximum residue limits recommended by European Union, while concentration of heavy metals in all the samples except Mn was below the maximum concentration limits recommended by Food and Agriculture Organization. The high concentration of pesticide residues in the samples indicates contaminated environment in which the bees fed; therefore intermittent monitoring of the quality of honeys produced would be necessary as this calls for urgent attention.
The objective of this study is to design an elastic neutron scattering system ac-cording to the angle with a sample using thermal neutron beam at the Dalat Nuclear Reactor (DNR). The system is used for research and training in the field of material structure analysis by neutron scattering and diffraction techniques. It is designed on the basis of inheriting the neutron measurement spectrometer systems at the DNR and the scattered neutron measurement systems in the world. The measuring system, which was installed at the horizontal channel 4 of the DNR, consists of 5-helium-3 detectors and a fully electronic system to record the scatter counts and a mechanical system with the possibility of rotating at 15˚ - 75˚ angles. The constructed system is tested for evaluation of the accuracy, stability and reliability of the mechanical and electronic systems of moving detectors by angles.
The study intended to determine the relationship between locus of control and academic achievement of secondary school students. Some students have been observed to achieve higher while some achieve lower even after being exposed to the same subject matter by the same instructor. The objective of the study was to determine if locus of control correlated with academic achievement of students as moderated by gender and school-type. The study was anchored on attribution theory. The study adopted a correlational research design. A total of 388 SS3 students in Aba Education zone were selected using purposive and simple random sampling techniques. Instruments for data collection were an adopted LOC scale and students’ exam scores in Mathematics, English and CRS. To determine the reliability of the instrument, Kuder-Richardson reliability test (KR-20) was employed and an overall coefficient of 0.76 was obtained for LOC scale. Data were analyzed using Pearson Product Moment Correlation Coefficient. Results showed significant relationship between locus of control and academic achievement of male students. Results also showed significant relationship between locus of control and academic achievement of public school students. Based on the findings, it was recommended that school authority should encourage good performance by rewarding students with excellent performance, because when good behaviour is rewarded, the individual is motivated to do better. Also, government should also provide the schools with necessary infrastructures that would make teaching and learning very interesting.
Eco-friendly Ultra-high-performance liquid chromatography (UHPLC) with green aqueous-organic mobile phase was applied for the simultaneous determination of febuxostat (FEB) and diclofenac (DIC) with the composition of water:ethanol (85:15 v/v) utilizing phenomenex Kinetex C18 column (4.6 × 100 mm 2.6 μm), flow rate 1 ml/min and UV detection at 280 nm with linear ranges of 0.4 - 4.0 μg/mL and 0.5 - 5.0 μg/mL for FEB and DIC, respectively. The proposed method was also successfully applied to analyze the two drugs in pharmaceutical dosage form and human plasma. The results obtained were validated and statistically analyzed and found to be in accordance with those given by reported methods. Moreover, the greenness of the developed method is assessed using suitable analytical Eco-Scale and GAPI tools and comparison with the previously published methods have been carried out to indicate the priority of the proposed method. UHPLC is considered eco-friendly method regarding uses of safe solvents, simple, accurate and short time of analysis.
Technetium-99 is a radioactive isotope with a half-life of 2.13 × 105 year. 99Tc is a significant contaminant of concern to the world. For this reason, a detailed understanding of technetium chemistry is essential for the protecting the public and the environment especially after increasing the various applications and uses of isotopes in the medical practices. Therefore, treatment of waste increases prior to the safe discharge to the environment or the storage. The sorption of technetium in the form of pertechnetate on a nano manganese oxide loaded into activated carbon has been investigated. Nano manganese oxide (NMO) was synthesized from manganese chloride and potassium permanganate by co-precipitation and forming a new composite by loading a nanoparticle into a modified activated carbon by different ratios. Modifications of activated carbons using different concentrations of HNO3 (4 M, 6 M and 8 M) are used in prepared composites. Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to characterize the prepared composites. The adsorption of anions from low level radioactive aqueous waste was examined using batch technique. Different parameters affecting on the adsorption process were studied for the removal of . The results revealed that NMO/AC (4 M, 6 M and 8 M) has a high adsorption efficiency (93.57%, 90.3% and 90.3%) respectively compared to NMO and AC which have a lower adsorption efficiency (41% and 38.9%) respectively. Moreover, the adsorption isotherm belonged to Freundlich model, the adsorption data followed pseudo-second order model and the thermodynamic study indicated that the adsorption of on Nano-composites was an exothermic and spontaneous process.
The degradation of the alkanolamine solvent used in the removal of acid gases from natural gas streams due to exposure to contaminants, thermal degradation and presence of oxygen or oxygen containing compounds will change the solvent properties, such as heat transfer coefficient, diffusion coefficient, and mass transfer coefficient of the solvent. Therefore, characterization and quantification of amine degradation product becomes one of the important analyses to determine alkanolamine solvent’s health. In order to identify degradation products of alkanolamine solvent, analytical strategies by using mass spectrometry (MS) as detector have been studied extensively. In this work, due to the low concentration of the amine degradation product, a method was developed for identification of alkanolamine degradation products using LCMS-QTOF technique. A strategy for identification of trace degradation products has been identified. Six (6) alkanolamine degradation products had been identified by using LCMS-QTOF targeted analysis in the blended alkanolamine solvent used in natural gas processing plant. Another fifteen (15) molecular formulas having similarity in chemical structure to alkanolamine degradation products were identified using untargeted analysis strategy, as possible compounds related to degradation products. Using LCMS-QTOF via targeted and untargeted analysis strategy, without tedious column separation and reference standard, enables laboratory to provide a quick and indicative information for alkanolamine solvent’s organic degradation compounds identification in CO2 adsorption, within reasonable analysis time.
This work is interested in solving the complex problem of understanding mass transfers in biological media. The contribution of the initial sample size is taken into account. Transfers are established more efficiently in small samples. Thus, from the first 50 minutes, the cubic sample at 1 cm stop is already at 50% while the sample at 4 cm edge is at about 90% of its initial water content. Likewise the shape is combined with the size. But it is revealed that if we fix similar characteristic dimensions, we can bypass the notion of initial shape. Thus the cubic samples 4 cm of edges. 4 cm diameter of spherical shape, 4 cm × 4 cm height-diameter cylindrical one, all dry identically.
