219 research outputs found

    The Influence of Oxidizing Parameters on the Formation of Oxide Layer as a Precursor for the Fabrication of Carbon Fiber-Steel Laminate

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    The application of fiber metal lamination has been increasing in the engineering industries such as the aerospace, automotive, construction and processing industries. Fiber metal lamination are able to provide a solution to improve metallic materials’ characteristics while improving the fibers’ properties at the same time. With high reliability and cheaper alternative to provide superior properties in material, in fabricating the fiber metal laminates, the surface of contact between the metal and the fiber is a fundamental criterion. The stability of the surface of the metallic substrate is key in avoiding delamination of the fiber metal laminate due to corrosion under insulation where the metallic surface that is bonded with the fiber are decomposed. In this paper, the influence of oxide formation on carbon steel which is a precursor to carbon fiber steel laminate surface discussed with different oxidizing parameters, which are temperature, time, heating rate and surface roughness on the formation of stable oxide layer. An optimum set of oxidizing parameter and levels are determined using the Analysis of Mean (ANOM) technique in Taguchi’s method, and the contribution of each oxidizing parameter in the formation of magnetite layer is done using the Analysis of Variance (ANOVA) method

    A spatial decision support system for the analysis of environmental impacts of integrated crop-livestock production system

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    Recent shifts toward intensive and large confined livestock production units to enhance economic growth coupled with increased concerns for air, soil, and water quality have necessitated the development of computer-based management decision support systems for selecting environmentally sound production sites and for planning sustainable production systems. This dissertation describes the development and application of an interactive spatial decision support system that integrates a geographic information system, spatial and biophysical modeling, and a knowledge-based system into an interactive tool to facilitate planning and management of environmentally-sound livestock production. The spatial decision support can be used to select suitable watershed land areas for siting livestock production, to select fields for manure application, and to determine the potential impacts of livestock production practices on ground and surface water quality. The site selection component of the spatial decision support system is based on the ARC/INFO geographic information system and incorporates the effects of land use, soil type, topography, proximity to roads and surface water bodies, and other aesthetic and political considerations as well as multicriteria analysis techniques. The groundwater quality modeling component of the decision support system integrates a geographic information system and water quality modeling, using training sets from NLEAP water quality modeling, to estimate nitrate leaching. In order to evaluate nutrient loading on surface water from integrated crop-livestock production a surface water quality model capable of incorporating the spatial dynamics of watershed was needed. The AGNPS distributed-parameter model was used for this purpose. The AGNPS model integrated with ARC/INFO GIS forms a user-friendly modeling interface for surface water quality analysis. The interface automates extraction of the input parameters from GIS data layers and allows the user to interactively generate scenarios of nutrient management practices in crop-livestock production. In order to demonstrate utility of the integrated system, example applications were performed on 7075-ha Lake Icaria watershed in southern Iowa

    Design of Low Power and Power Scalable Pipelined ADC Using Current Modulated Power Scale

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    This work represents a power scalable pipelined ADC, which achieves low power variation depends upon the sampling rate and enables variation in throughput. The keys to power scalability at high sampling rates were current modulation-based architecture and the development of novel rapid power-on Op-amp, which can completely and quickly power on/off by the feedback approach. The result achieved in this design is as high as 50 Msps and as low as 1 ksps, keeping some important parameters of ADC as ENOB and SNDR are almost constant. Power variation in ADC has a flexible range from 7.5 µW to 17 mW, which is lower power consumption than previous works

    A study of the clinical profile of 50 patients of COPD with correlation between clinical, radiological and spirometric evaluation

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    Background: Chronic obstructive pulmonary disease (COPD) is a common, preventable and treatable disease that is characterised by persistent respiratory symptoms and airflow limitation that is due to airway and/ or alveolar abnormalities usually caused by significant exposure to noxious particles or gases. Tobacco smoking, occupational exposure to organic and inorganic dusts, chemical agents and fumes and biomass cooking are the risk factors for COPD. Chronic dyspnoea, cough, sputum production, wheezing and chest tightness are the common symptoms of COPD. The present study was undertaken to evaluate the clinical, radiological and spirometric parameters in patients with COPD and to demonstrate a correlation between them.Methods: This was a prospective study of 50 patients of COPD who presented to out- patient department. We included all patients above 40 years of age with a smoking index of 200 or more, or history of exposure to occupational dust, biomass fuel gas or exposure to other obnoxious gases; and who had history of dyspnoea and cough. Spirometry was performed to confirm the diagnosis and to grade the severity of airflow obstruction. History of dyspnoea, cough, sputum production, wheezing, chest tightness, fever, weight loss and the number of exacerbations in the previous year was noted. We then performed a detailed clinical examination. Blood was sent for haemogram and arterial blood gas analysis and all patients underwent an ECG, 2- D Echo and HRCT of the thorax. We then studied the correlation between the clinical, radiological and spirometric profiles in these patients.Results: Out of the 50 patients, majority was between 50-59 years of age, with male to female ratio of 1.94:1.00. History of smoking was present in 74% patients, exposure to biomass fuel in 12% and exposure to occupational dust in 6% patients. Commonest symptom was dyspnoea (in 100% patients) followed by cough (88%), sputum production (68%), wheezing (58%), chest tightness and fever (30%) and weight loss (28%). HRCT was positive in 75% patients, while ECG changes were seen in 42% patients and pulmonary hypertension was present in 54% patients. A significant association was observed between grade 5 dyspnoea on mMRC, hypoxia, hypercarbia, pulmonary hypertension and Gold-5 airflow obstruction.Conclusions: In the present study of 50 cases, COPD was seen predominantly in male patients, with a mean age of presentation between 50- 59 years. Tobacco smoking was the commonest etiological factor. Clinical symptoms most commonly documented were dyspnoea, cough with or without expectoration, wheezing, chest tightness, fever and weight loss. A significant association was observed between grade 5 dyspnoea on mMRC, hypoxia, hypercarbia, pulmonary hypertension and Gold-5 airflow obstruction

    Portal biliopathy

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    In patients with portal hypertension, particularly with extrahepatic portal vein obstruction, portal biliopathy producing biliary ductal and gallbladder wall abnormalities are common. Portal cavernoma formation, choledochal varices and ischemic injury of the bile duct have been implicated as causes of these morphological alterations. While a majority of the patients are asymptomatic, some present with a raised alkaline phosphatase level, abdominal pain, fever and cholangitis. Choledocholithiasis may develop as a complication and manifest as obstructive jaundice with or without cholangitis. Endoscopic sphincterotomy and stone extraction can effectively treat cholangitis when jaundice is associated with common bile duct stone(s). Definitive decompressive shunt surgery is sometimes required when biliary obstruction is recurrent and progressive

    Chemical Composition and In Vitro Cytotoxic Activity of Essential Oil of Leaves of Malus domestica Growing in Western Himalaya (India)

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    Light pale-colored volatile oil was obtained from fresh leaves of Malus domestica tree, growing in Dhauladhar range of Himalaya (Himachal Pradesh, India), with characteristic eucalyptol dominant fragrance. The oil was found to be a complex mixture of mono-, sesqui-, di-terpenes, phenolics, and aliphatic hydrocarbons. Seventeen compounds accounting for nearly 95.3% of the oil were characterized with the help of capillary GC, GC-MS, and NMR. Major compounds of the oil were characterized as eucalyptol (43.7%), phytol (11.5%), α-farnesene (9.6%), and pentacosane (7.6%). Cytotoxicity of essential oil of leaves of M. domestica was evaluated by sulforhodamine B (SRB) assays. The essential oil of leaves of M. domestica, tested against three cancer cell lines, namely, C-6 (glioma cells), A549 (human lung carcinoma), CHOK1 (Chinese hamster ovary cells), and THP-1 (human acute monocytic leukemia cell). The highest activity showed by essential oil on C-6 cell lines (98.2%) at concentration of 2000 μg/ml compared to control. It is the first paper in literature to exploit the chemical composition and cytotoxic activity of leaves essential oil of M. domestica

    Power systems automation, communication, and information technologies for smart grid: A technical aspects review

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    Smart grid (SG) introduced proven power system, based on modernized power delivery system with introduction of advanced data-information and communication technologies (ICT). SGs include improved quality of power transmission/distribution from power generation to end-users with optimized power flow and efficiency. In addition to above modern automation, two-way communications, advanced monitoring, and control to optimize power quality issues are the classic features of SGs. This ensures the efficiency and reliability of all its interconnected power system elements against potential threats and life time cycle. By integrating ICT into the power system SGs improved the working capabilities of the utility companies. Resultant of ICT with SG leads to better management of assets and ensure energy management for end users. This review article presents the different areas of communication and information technology areas involved in SG automation

    Catalytic methane decomposition to carbon nanostructures and cox-free hydrogen: A mini-review

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    Catalytic methane decomposition (CMD) is a highly promising approach for the rational production of relatively COx-free hydrogen and carbon nanostructures, which are both important in multidisciplinary catalytic applications, electronics, fuel cells, etc. Research on CMD has been expanding in recent years with more than 2000 studies in the last five years alone. It is therefore a daunting task to provide a timely update on recent advances in the CMD process, related catalysis, kinetics, and reaction products. This mini-review emphasizes recent studies on the CMD process investigating self-standing/supported metal-based catalysts (e.g., Fe, Ni, Co, and Cu), metal oxide supports (e.g., SiO2, Al2O3, and TiO2), and carbon-based catalysts (e.g., carbon blacks, carbon nano-tubes, and activated carbons) alongside their parameters supported with various examples, sche-matics, and comparison tables. In addition, the review examines the effect of a catalyst's shape and composition on CMD activity, stability, and products. It also attempts to bridge the gap between research and practical utilization of the CMD process and its future prospects.This research was funded by Qatar Shell, grant number QUEX-CENG-SHELL-19/20-1.Scopu
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