307 research outputs found

    Thermodynamic optimization tools for power tracking in a multistage concentrated solar power Rankine plant

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    Abstract: The object of the study is to present a method of thermodynamic optimization of power generating plants, in a mode that consolidates and simplifies the analysis of data on heat-work interaction of the plant components. The optimization scheme identifies the technical and process parameters that can improve the thermodynamic performance of the plant with respect to an objective variable, and further, the required thermodynamic measures necessary to improve the operating condition of the plant. Simple but effective tools are used to evaluate the optimal and suboptimal power generating capacities vis-à-vis the fundamental variables—namely, the thermodynamic quantity ratio (TQR) and the power-energy quantity ratio (PQR)—without routing optimization procedures. Beyond the optimal value of the objective variable, the power generation capacity of the plant is affected. The determination of the optimal value of the objective variable can also be approached by computerization; for fixed prescriptions of the boiler, superheater, and turbine parameters, variables such as boiler pressure and temperature can be optimally selected. DOI: 10.1061/(ASCE)EY.1943-7897.0000367. © 2016 American Society of Civil Engineers

    Optimal Analysis of Packaging Products of MAHEU Plant in Intafact Beverages Limited Using GPALS and MATLAB Optimization Software

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    This work focused on the optimization of the two packaging products; Supershake and Chibuku made up of three and two parts respectively. Copolymer polypropylene and white or colored batch materials are the two raw materials needed to produce the two packaging products. The manufacturing plan was developed for the organization. The production inputs of 1.11, 6.67, 15.78, 2.47 and 7.70 units were generated as the objective function coefficients; 308 hours per month for day shift and 364 hours per month for night shift were established. Production time of 10 seconds, 20 seconds, 12 second, 10 seconds and 12 seconds per unit of the five parts were established. The manufacturing constraints in terms of machine capacities, material availability, time and labour were extensively used to develop an integer linear programming model to obtain the optimum quantities of each part that will yield the maximum profit. The developed model was analyzed with GPALS and MATLAB optimization solver to obtain results for the linear programming model which gave a monthly production net profit of N3,751,932. A decision support system was developed for the manufacturing planning to assist the management of Maheu plant in Intafact Beverages Limited in decision making. The model is now being used in the manufacturing plan of the company and also recommended for application in organizations with similar production inputs. Keywords: Manufacturing plan, Production inputs, Manufacturing constraints,  Optimization, Profit and Decision makin

    Kinetics and Equilibrium of Crude Oil Sorption from Aqueous Solution Using Borassus Aeothopum Coir

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    In this study, Borassus aethopum coir (BAC) which is an abundant, cheap, readily available and biodegradable agricultural waste was modified by acetylation using acetic anhydride and NBS catalyst at room temperature. This was to increase their hydrophobic properties and improve their sorption capacity in aqueous environment. The crude oil sorption kinetic data were fitted by intra-particle diffusion and pseudo-first order for raw BAC but the pseudo-second order kinetic model best fits crude oil sorption data for acetylated BAC.  The Langmuir and Freundlich models were used to elucidate the sorption behaviour of crude oil with raw and acetylated BAC. Freundlich isotherm gave the best fit for the equilibrium crude oil sorption data for acetylated BAC and raw BAC. Fourier transform infrared and scanning electron microscope analyses showed clear evidence of successful acetylation. The results presented and discussed in the study suggests that acetylated BAC (ABAC) is more suitable for crude oil sorption than raw BAC, therefore, possesses more potential for application and further development in treatment of oil spillage. Keywords: acetylated borassus aethopum coir, kinetics, crude oil sorption, sorbents, sorption capacity. DOI: 10.7176/CMR/11-2-02

    Genetic Variation for Striga hermonthica Resistance and Yield Among Sorghum Accessions in Nigeria

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    Striga hermonthica (Delile) Benth., commonly referred to as witch weed, is a major constraint to sorghum (Sorghum bicolor (L.) Moench) production in the Northern region of Nigeria because of high yield losses due to infestation. To identify parental lines useful in breeding for S. hermonthica resistant sorghum genotypes adapted to Nigeria, twenty-five sorghum accessions were evaluated in Nigeria across three test environments. Both phenotypic and genetic components influenced the variation observed in the sorghum accessions. The estimates for the genetic coefficient of variation, heritability and genetic advance for the area under Striga number progress curve (ASUNPC), Striga emergence counts, yield and other agronomic traits, obtained in this study revealed that genetic gain for resistance to S. hermonthica could be realized through selection. Based on the performance of the 25 sorghum accessions SRN39, Danyana, Sepon82, and SAMSORG40 were the top four accessions found to be most resistant to S. hermonthica. Assessment of resistance was based on the low Striga emergence counts and the ASUNPC values. These accessions can be used as donor sources of S. hermonthica resistant genes for introgression into cultivars adapted to Nigeria, followed by recombination breeding for pyramiding the different resistance mechanisms

    Assessment of remediation Potentials of maize (Zea mays) on sites co-contaminated with Pb and antracene

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    Phytoremediation is a promising technology for the remediation of sites co-contaminated with inorganic and organic pollutants. A pot experiment was conducted to evaluate the remediation potential of Z.mays in soil co- contaminated with Pb and antracene. Pristine sandy loam soils were polluted with Pb chloride salt and antracene at three different levels (50mg/kg of Pb, 100mg/kg of Pb, and 100mg/kg of Pb+100mg/kg of antracene) and laid out in completely randomized design with 3 replicates. Shoot dry matter weight was significantly reduced (p≤0.05) when compared with control treatments by 40% when exposed to100mg kg-1 of Pb. There was a 48% inhibition of shoot dry matter of Z.mays relative to control treatments when 100 mg Pb kg-1 was mixed with 100 mgkg-1 antracene. Root and shoot metal concentration in Zea mays increased with increasing concentration of Pb. The average Translocation Factor (TF < 1 (0.69) obtained suggests that Zea mays predominantly retains Pb in the root portion of the plant. There was a 5% increase in shoot Pb concentration when soil was contaminated with Pb and antracene. The extractable antracene decreased significantly (p≤0.05) in soil planted with Z.mays as well as in pots without maize plant. This accounted for 65 and 72% of antracene dissipation in planted soil and 40-46% dissipation in unplanted soil. This result suggested that Zeamays is a promising candidate for uptake Pb and dissipation of antracene in co-contaminated soils

    Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) accessions using single nucleotide polymorphism markers

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    Sorghum (Sorghum bicolor (L.) Moench) is an important resource to the national economy and it is essential to assess the genetic diversity in existing sorghum germplasm for better conservation, utilization and crop improvement. The aim of this study was to evaluate the level of genetic diversity within and among sorghum germplasms collected from diverse institutes in Nigeria and Mali using Single Nucleotide Polymorphic markers. Genetic diversity among the germplasm was low with an average polymorphism information content value of 0.24. Analysis of Molecular Variation revealed 6%variation amonggermplasmand 94%withingermplasms.Dendrogramrevealed threegroupsof clusteringwhich indicatevariationswithinthegermplasms. Privatealleles identified inthesorghum accessions from National Center for Genetic Resources and Biotechnology, Ibadan, Nigeria and International Crop Research Institute for the Semi-Arid Tropics, Kano, Nigeria shows their prospect for sorghum improvement and discovery of new agronomic traits. The presence of private alleles and genetic variation within the germplasms indicates that the accessions are valuable resources for future breeding programs

    Does PhD Qualification Improve Pedagogical Competence? A Study on Teaching and Training in Higher Education

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    Purpose: There has been much debate in recent times about the factors that improve the quality of teaching in higher education (HE) institutions. This has been especially fuelled by the increasing importance attached to Doctor of Philosophy (PhD) qualification. To fill the existing gap in the current literature in this regard, this study aims to investigate whether HE teachers (lecturers) who undergo pedagogical training (PT) in addition to obtaining PhD qualification possess higher knowledge and pedagogical competencies (PCs) than those that relied only on having PhD qualification without further teaching qualifications. Design/Methodology/Approach: Drawing upon data collected through a structured questionnaire administered to 1174 Nigerian HE teachers in various disciplines from 39 HE institutions, in addition to two focus groups; the study adopts a mixed methods research. The quantitative data were analyzed descriptively while qualitatively data were coded, transcribed verbatim and analyzed thematically. Findings – This article proposes that teachers who undergo PT in addition to obtaining PhD tend to have more PCs and perform better than those that have not undergone any form of PT. Also, it found a statistically significant difference between PCs of HE teachers who have undergone PT in addition to PhD qualification from those without PT. The implication is that teachers who have undergone PT are more effective in facilitating teaching and learning than those who have not completed PT. Research Limitations/Implications: Despite the merits of the mixed research method, a major limitation of this study is the failure to compare students’ achievements or successes based on the two distinct samples. However, the limitations create opportunities for further studies into the subject matter. Originality/Value – This study is timely, given that Nigeria (like many African countries) has a low quality HE system and low graduate outcomes (related to knowledge, employability, and skills). More so, research into pedagogical content knowledge (PCK) and practices are rare or non-existent in the literature related to Nigeria and other African countries’ HE system

    The association of hydration status with physical signs, symptoms and survival in advanced cancer-The use of Bioelectrical Impedance Vector Analysis (BIVA) technology to evaluate fluid volume in palliative care: An observational study

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    Background Hydration in advanced cancer is a controversial area; however, current hydration assessments methods are poorly developed. Bioelectrical impedance vector analysis (BIVA) is an accurate hydration tool; however its application in advanced cancer has not been explored. This study used BIVA to evaluate hydration status in advanced cancer to examine the association of fluid status with symptoms, physical signs, renal biochemical measures and survival. Materials and methods An observational study of 90 adults with advanced cancer receiving care in a UK specialist palliative care inpatient unit was conducted. Hydration status was assessed using BIVA in addition to assessments of symptoms, physical signs, performance status, renal biochemical measures, oral fluid intake and medications. The association of clinical variables with hydration was evaluated using regression analysis. A survival analysis was conducted to examine the influence of hydration status and renal failure. Results The hydration status of participants was normal in 43 (47.8%), 'more hydrated' in 37 (41.1%) and 'less hydrated' in 10 (11.1%). Lower hydration was associated with increased symptom intensity (Beta = -0.29, p = 0.04) and higher scores for physical signs associated with dehydration (Beta = 10.94, p = 0.02). Higher hydration was associated with oedema (Beta = 2.55, p<0.001). Median survival was statistically significantly shorter in 'less hydrated' patients (44 vs. 68 days; p = 0.049) and in pre-renal failure (44 vs. 100 days; p = 0.003). Conclusions In advanced cancer, hydration status was associated with clinical signs and symptoms. Hydration status and pre-renal failure were independent predictors of survival. Further studies can establish the utility of BIVA as a standardised hydration assessment tool and explore its potential research application, in order to inform the clinical management of fluid balance in patients with advanced cancer

    Single-cell sequencing reveals clonal expansions of pro-inflammatory synovial CD8 T cells expressing tissue-homing receptors in psoriatic arthritis

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    Psoriatic arthritis (PsA) is a debilitating immune-mediated inflammatory arthritis of unknown pathogenesis commonly affecting patients with skin psoriasis. Here we use complementary single-cell approaches to study leukocytes from PsA joints. Mass cytometry demonstrates a 3-fold expansion of memory CD8 T cells in the joints of PsA patients compared to peripheral blood. Meanwhile, droplet-based and plate-based single-cell RNA sequencing of paired T cell receptor alpha and beta chain sequences show pronounced CD8 T cell clonal expansions within the joints. Transcriptome analyses find these expanded synovial CD8 T cells to express cycling, activation, tissue-homing and tissue residency markers. T cell receptor sequence comparison between patients identifies clonal convergence. Finally, chemokine receptor CXCR3 is upregulated in the expanded synovial CD8 T cells, while two CXCR3 ligands, CXCL9 and CXCL10, are elevated in PsA synovial fluid. Our data thus provide a quantitative molecular insight into the cellular immune landscape of psoriatic arthritis

    Single-cell sequencing reveals clonal expansions of pro-inflammatory synovial CD8 T cells expressing tissue-homing receptors in psoriatic arthritis.

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    Psoriatic arthritis (PsA) is a debilitating immune-mediated inflammatory arthritis of unknown pathogenesis commonly affecting patients with skin psoriasis. Here we use complementary single-cell approaches to study leukocytes from PsA joints. Mass cytometry demonstrates a 3-fold expansion of memory CD8 T cells in the joints of PsA patients compared to peripheral blood. Meanwhile, droplet-based and plate-based single-cell RNA sequencing of paired T cell receptor alpha and beta chain sequences show pronounced CD8 T cell clonal expansions within the joints. Transcriptome analyses find these expanded synovial CD8 T cells to express cycling, activation, tissue-homing and tissue residency markers. T cell receptor sequence comparison between patients identifies clonal convergence. Finally, chemokine receptor CXCR3 is upregulated in the expanded synovial CD8 T cells, while two CXCR3 ligands, CXCL9 and CXCL10, are elevated in PsA synovial fluid. Our data thus provide a quantitative molecular insight into the cellular immune landscape of psoriatic arthritis
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