683 research outputs found

    Resource Accounting in Factories and the Energy-Water Nexus

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. open access articleA manufacturing system comprises production processes and building services, both of which are supplied by different energy carriers as well as raw materials and water. These resources interact according to complex relationships and are converted into products for sale and waste flows. Holistic resource accounting allows the analyst to consider the dynamic relationships between these components, including the strong interdependence between energy and water, which has been called the energy-water nexus. Exergy analysis is a method that accounts for mass and both the quantity and quality of energy, while allowing analysis on a common basis and for this reason it is used increasingly to analyse resource consumption in manufacturing systems; however it has rarely been used to consider water flows alongside energy and material flows. The main contribution of this paper is the presentation of modeling water flows in terms of exergy in the context of sustainable manufacturing. Using this technique in combination with previously developed exergy based methods; the result is a truly holistic resource accounting method for factories based on exergy analysis that incorporates water flows. The method is illustrated using a case study of a food factory in which a 4.1% reduction in resource use is shown to be possible by employing anaerobic digester in an effluent water treatment process. The benefits of this technology option would have been underestimated compared to the benefits of waste heat capture if an analysis based on mass and energy balances alone had been used. The scientific value of this paper is the demonstration of the relatively high exergy content of effluent flows, which should therefore be regarded as potentially valuable resources. The analytical method presented is therefore of value to a wide range of industries beyond the food industry

    Satl model lesson in chemical kinetics

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    Studies in order to pursue kinetics and mechanism of chemical reactions are a vital component of chemical literature. SATL literature is still not available for promoting this vital aspect of chemistry teaching. A lesson pertaining to this important issue has been developed and various parameters of kinetic studies are explained therein.[AJCE, 3(1), January 2013

    Study of the histidine complex of uranium(IV): synthesis, spectrophotometric, magnetic and electrochemical properties

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    We synthesized the novel histidine complex of uranium(IV). A 1:3 mole ratio was found between metal and ligand by the mole ratio method, while –NH2 and –COO– groups of histidine behave as coordinating sites. The IR spectra confirmed the lone pair donating or coordinating sites. The elemental analysis confirmed the stoichiometry. The bathochromic shift with an increase in the optical density in the UV-Visible range indicated that the compound and its central metal ion hold uniform electronic charge distribution. The electrochemical results indicated a quasi-reversible (neither completely reversible nor completely irreversible) oxidation of the complex to its uranium(V) product at the platinum working electrode. The quasi-reversible process shows a comparatively slow electron transfer (ET) rate with the heterogeneous electron transfer rate constant ‘ks’ (3.4 ×  10–4 cm s-1) at 50 mV s-1 and 305 ± 0.5 K. The kinetics such as diffusion and charge transfer lead the reaction with an ECE (electrochemical–chemical–electrochemical) mechanism. The thermodynamic parameters of activation such as ΔH*; 4.257 kJ mol–1, ΔS*; -2.519 × 10–3 J mol–1 K–1 and ΔG* 4.26 kJ mol–1 helped to propose an associative mechanism of the electron transfer at the platinum working electrode.                     KEY WORDS: Uranium, Histidine, Spectroscopy, Electrochemistry, Kinetics   Bull. Chem. Soc. Ethiop. 2020, 34(3), 557-569.  DOI: https://dx.doi.org/10.4314/bcse.v34i3.1

    Germline Transgenic Methods for Tracking Cells and Testing Gene Function During Regeneration in the Axolotl

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    The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum(axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible

    Muscle healing and nerve regeneration in a muscle contusion model in the rat

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    The nervous system is known to be involved in inflammation and repair. We aimed to determine the effect of physical activity on the healing of a muscle injury and to examine the pattern of innervation. Using a drop-ball technique, a contusion was produced in the gastrocnemius in 20 rats. In ten the limb was immobilised in a plaster cast and the remaining ten had mobilisation on a running wheel. The muscle and the corresponding dorsal-root ganglia were studied by histological and immunohistochemical methods.In the mobilisation group, there was a significant reduction in lymphocytes (p = 0.016), macrophages (p = 0.008) and myotubules (p = 0.008) between three and 21 days. The formation of myotubules and the density of nerve fibres was significantly higher (both p = 0.016) compared with those in the immobilisation group at three days, while the density of CGRP-positive fibres was significantly lower (p = 0.016) after 21 days.Mobilisation after contusional injury to the muscle resulted in early and increased formation of myotubules, early nerve regeneration and progressive reduction in inflammation, suggesting that it promoted a better healing response

    Towards improved energy and resource management in manufacturing

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    The file attached to this record is the author's final peer reviewed version.Exergy analysis has widely been used to assess resource consumption, and to identify opportunities for improvement within manufacturing. The main advantages being its ability to account for energy quality and consumption. However, its application in industrial practice is limited, which may be due to the lack of its consistent application in practice. Current energy management standards, that facilitate consistent application of procedures, do not consider the quality aspects of energy flows. An exergy based energy management standards is proposed in this paper that would take into account energy quality aspects, while facilitating the consistent application of exergy analysis in industrial practice. Building on ISO50001, this paper presents guidelines for implementing energy and resource management in factories, incorporating the concepts of exergy and holistic factory simulation, illustrated through a manufacturing case study. From the factory level analysis, a chilling process was identified to have significant improvement potential. A dry fan cooler, using ambient air was proposed for improved efficiency of the chillers. Energy based metrics portrayed a system that operated at high efficiency, however exergy analysis indicated much room for further improvement, therefore impacting decision making for technology selection. The contribution of this paper is in presenting a set of prescriptive guidelines that could possibly be further developed into a new energy management standard that would utilize the advantages of exergy analysis towards improved energy and resource management in manufacturing

    Enhanced He-alpha emission from "smoked" Ti targets irradiated with 400nm, 45 fs laser pulses

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    We present a study of He-like 1s(2)-1s2p line emission from solid and low-density Ti targets under similar or equal to 45 fs laser pulse irradiation with a frequency doubled Ti: Sapphire laser. By varying the beam spot, the intensity on target was varied from 10(15) W/cm(2) to 10(19) W/cm(2). At best focus, low density "smoked" Ti targets yield similar to 20 times more He-alpha than the foil targets when irradiated at an angle of 45 degrees with s-polarized pulses. The duration of He-alpha emission from smoked targets, measured with a fast streak camera, was similar to that from Ti foils

    Diabetes and atypical presentations of patients hospitalized for an acute myocardial infarction in Puerto Rico

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    Introduction: Diabetes mellitus is one of the fastest growing health issues concerning the world today with an estimated 382 million individuals affected as of 2013 and a projected increase in number to 592 million by 2035. Diabetes mellitus is a condition affecting 12-15% of the population or around 400,000 people in Puerto Rico. The most common presenting complaint of diabetics who are hospitalized for an acute myocardial infarction (AMI) is chest pain. However, the pervasiveness of atypical symptoms in diabetic patients is yet unclear. The aim of this study is to determine if there is an association between diabetes and the presentation of atypical symptoms in the emergency room in those suffering from an AMI in Puerto Rico. Methods: We conducted a secondary data analysis of data from participants from the 2007, 2009 and 2011 Puerto Rico Cardiovascular Disease Surveillance system (PRCDS), an observational, non-concurrent, cross-sectional study. The main independent variable was presence of diabetes mellitus (Type I and Type II). The outcome was the presence of atypical symptoms at the time of presentation, defined as the absence of chest pain on admission. The prevalence of atypical symptoms in diabetic patients and non-diabetic patients was compared. Binary logistic regression was used to test for independent association. Statistical significance was considered for p-values ≤0.05 for a two-tailed test. Analysis was conducted using SPSS software. Results: We found no association between atypical presentation of an AMI and diabetes, before or after adjustment for age, gender, congestive heart failure, stroke history and BMI. (unadjusted OR= 1.0, 95%CI=0.7-1.4 and adjusted OR=1.0, 95% CI=0.6-1.5). Other independent associations identified were that patients older than 75 were 3.5 times more likely to present atypically than people younger than 55 (OR= 3.5, 95% CI=1.6-7.6), and those with CHF and stroke were more likely to present with atypical symptoms (OR=3.2, 95% CI=1.7-6.1 and OR=4.2 95% CI=2.1-8.4, respectively). Lastly, overweight patients were 3.3 times more likely to present atypically than healthy weight patients (OR=2.0, 95% CI=0.6-7.0). Conclusion: We found no evidence of an association between diabetes and the presentation of atypical symptoms in patients hospitalized for AMI in Puerto Rico

    Phytochemical analysis of selected medicinal plants

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    Four medicinal plants including Ranunculus arvensis, Equisetum ravens, Carathamus lanatus and Fagonia critica were used for the study. All the plants were biologically active and were used for different types of ailments. Keeping in view their importance, this work was carried out to investigate the quantitative determination of their crude phytochemicals, vitamins and protein contents. The quantitative determination of crude phytochemicals (alkaloids, total phenols, flavonoids and saponins) vitamins (riboflavin, vitamin C, niacin and pectin) and protein were determined in the aforementioned herbs. The phytochemicals including alkaloids, total phenols, flavonoids and saponins were determined quantitatively using literature methods. Vitamins were measured using a UV/ visible spectrophotometer (UV- 1601 Shamidzu) and the protein was determined by the Micro KJeldahl’s method (Horwitz et al., 2000). The studied plants showed variable amounts of phytochemicals, vitamins and protein contents. The study is very important, in that it intended to show the contents of the studied medicinal herbs and also provide a scientific data base line which is of particular importance for the local practioners as well as for the local people using these herbs for a variety of body disorders.Key word: Phytochemical analysis, medicinal plants, Pakistan

    Analysis of chemical constituents in medicinal plants of selected districts of Pakhtoonkhwa, Pakistan

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    Alkaloids, flavonoids and saponins were determined in the Teraxacam officinale, Cichorium intybus and Figonia tritica. Quantative determinations of crude alkaloids, flavonoids and saponins (g kg-1) and their percentages (%) were determined in C. intybus, T. officinale and F. critica collected from Kohat, Mardan, Nowshera and Peshawar regions. Thin layer chromatography (TLC) study of the alkaloids, flavonoids and saponins were carried out with different solvent systems and color of the spot and Rf value of each constituent was determined. Among the samples of C. intybus, relatively higher contents of alkaloids (14 g kg-1) were found in the sample collected from Mardan region, followed by the sample gathered from Nowshera which is equal to 13.8g kg-1. Higher contents of flavonoids were found in C. intybus collected from Kohat region which was 23.48 g kg-1. The other remaining samples of C. intybus ranged in the decreasing order of 19.7, 17.2 and 10.0 g kg-1 for the ones collected from Nowshera, Mardan and Peshawar, respectively. The overall saponin contents remained almost low as compared to the alkaloid and flavonoid contents.Key words: Alkaloids, flavonoids, saponins, TLC study, medicinal plants
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