2,288 research outputs found
Development and Numerical Optimization of a System of Integrated Agents for Serial Production Lines
In modern high-volume industries, the serial production line (SPL) is of growing importance due to the inexorable increase in the complexity of manufacturing systems and the associated production costs. Optimal decisions regarding buffer size and the selection of components when designing and implementing an SPL can be difficult, often requiring complex analytical models, which can be difficult to conceive and construct. Here, we propose a model to evaluate and optimize the design of an SPL, integrating numerical simulation with artificial intelligence (AI). Numerous studies relating to the design of SPL systems have been published, but few have considered the simultaneous consideration of a number of decision variables. Indeed, the authors have been unable to locate in the published literature even one work that integrated the selection of components with the optimization of buffer sizes into a single framework. In this research, a System of Integrated Agents Numerical Optimization (SIGN) is developed by which the SPL design can be optimized. A SIGN consists of a components selection system and a decision support system. A SIGN aids the selection of machine tools, buffer sizes, and robots via the integration of AI and simulations. Using a purpose-developed interface, a user inputs the appropriate SPL parameters and settings, selects the decision-making and optimization techniques to use, and then displays output results. It will be implemented in open-source software to broaden the impact of the SIGN and extend its influence in industry and academia. It is expected that the results of this research project will significantly influence open-source manufacturing system design and, consequently, industrial and economic development
Fatal elizabethkingia meningoseptica cholangitis following biliary stent placement
Elizabethkingia (E.) meningosepticais a ubiquitous gram-negative bacillus belonging to the genus Chryseobacteriumand has been reported to cause nosocomial infections in both the immunocompromised and immunocompetent patients. E. meningoseptica can colonize the biliary tree after endoscopic procedures; and cholangitis, caused by this organism, is associated with a favorable prognosis. Here, we report a fatal case of cholangitis secondary to E. meningoseptica that developed following biliary stent placement. This case suggests that E. meningoseptica can be a cause of potentially fatal biliary tract infections in patients who undergo biliary tract endoscopic procedures. Clinicians must not disregard this organism as a contaminant (or colonizer) as a delay in diagnosis and treatment can lead to a fatal outcome, as seen in this case
Determinants and cost of production of dates in Pakistan: An analytical study
Abctract. Present study is an attempt to analyse the production determinants and the cost of production of dates using causal approach of Ordinary Least Squares Methods using secondary data. The costs associated with the agriculture production are computed from labour costs, expenses incurring on the pesticides and fertilizers and the cost of seeds and amount of rent when the piece of land is acquired on contract basis. Provision of credit facility to the farmers and growers can play a major role in softening the constraints of the farmers and motivate them to enhance production of dates. Moreover, technical and technological advancement and adoption of the cost saving technology by farmers can also help farmers improve quality and per acre yield of their production. The findings of the study suggest that the employment in agriculture sector is the most important factor affecting production of dates followed by mechanization and technological advancement and third is the credit to the farmers. All coefficients have significance of less than 0.05 with substantially large generalizability power.Keywords. Production, Technology, Credit, Dates, Finance, Growers, Labour, Costs, Fertilizers, Pesticides, Seeds.JEL. D24, J08, Q16, H81
A Real-Time Flow Muskingum Forecasting Model for Three Main Stations of the Medjerda River (Tunisia)
Water Resources Planning and Managemen
Interleukin-18 polymorphism as an inflammatory index in metabolic syndrome: A preliminary study
Aim: To assess circulatory levels of interleukin-18 (IL-18) and determine whether the presence of IL-18 promoter polymorphism influences metabolic syndrome phenotypes.Methods: This study recruited one hundred and eighty individuals divided into three groups with sixty subjects each as: Normal weight (18.0-22.9 kg/m2), overweight (23.0-25.9 kg/m2) and obese (\u3e 26.0 kg/m2) according to South Asian criteria of BMI. Fasting blood glucose (FBG), Lipid profile, insulin, IL-18 and tumor necrosis factor (TNF)alpha were measured using ELISA kits, whereas low density lipoprotein (LDL)-cholesterol, insulin resistance (HOMA-IR) and insulin sensitivity (QUICKI) were calculated. The body fat percentage (BF) was measured through bioelectrical impedance analysis; waist and hip circumference were measured. Genotyping of IL-18 -607 C/A polymorphism was performed by using tetra-primer amplification refractory mutation system. Student t test, One-way analysis of variance, Hardy-Weinberg equilibrium, Pearson\u27s chi2 test and Pearson\u27s correlation were used, where a P value \u3c 0.05 was considered significant.Results: In an aged matched study, obese subjects showed higher levels of FBG, cholesterol, triglycerides and LDL levels as compared to normal weight (P\u3c 0.001). Highest levels of IL-18 and TNF levels were also seen in obese subjects (IL-18: 58.87 ± 8.59 ng/L) (TNF: 4581.93 ± 2132.05 pg/mL). The percentage of IL-18 -607 A/A polymorphism was higher in overweight and obese subjects vs normal weight subjects (P\u3c 0.001). Moreover, subjects with AA genotype had a higher BF, insulin resistance, TNFalpha and IL-18 levels when compared with subjects with AC (heterozygous) or CC (wild type) genotypes. However, we did not find any difference in the lipid profile between three subgroups.Conclusion: This preliminary data suggests that IL-18 polymorphism affects IL-18 levels that might cause low grade inflammation, further exacerbated by increased TNFalpha. All these increase the susceptibility to develop MetS. Further studies are required to validate our findings
Prevalence, Comparison, and Determinants of Smoking among Young Schoolchildren in Kingdom of Saudi Arabia
BACKGROUND: Smoking is one of the most serious health issues among all age groups, particularly in children globally including the Gulf region. However, there are little data about the prevalence in public and private schools and determinants of smoking among adolescents in Saudi Arabia.
AIM: The purpose of this study was to estimate the prevalence, compare, and determine smoking habits among male children in public and private schools.
METHOD: This cross-sectional study was conducted in Dammam city, KSA. The data were collected from 866 male children studying in public and private schools. Sample was calculated through stratified random sampling. The modified “Global Youth Tobacco Survey (GYTS)” was used to collect information.
RESULTS: The total number of children recruited was 866 (223 from private and 643 from public schools). The mean age of children studied was 14.20 ± 1.03 years in both groups. The result shows that overall 27.8% of children tried to smoke cigarette both in public and private schools. The prevalence of smoking is higher in public schools’ children than in private schools (30% vs. 21%; p = 0.005). In addition, wrong perception of comfortable feeling after smoking, easy access to cigarettes, parent’s addiction, and smoking in front of children are the determining factors.
CONCLUSION: This study suggests that the prevalence of cigarettes smoking among children exists in considerable proportion. It is higher in public schools children. The health and education authorities should take urgent steps to encounter this major health issue
Proteinase 3-antineutrophil cytoplasmic antibody positive necrotizing vasculitis induced by ciprofloxacin
Granulomatosis with polyangiitis (Wegener’s), microscopic polyangitis, and eosinophilic granulomatosis with polyangiitis are commonly grouped together as antineutrophil cytoplasmic antibody (ANCA)-positive vasculitides. Many drugs and infections can induce serologic positivity for ANCA, while a few can precipitate overt ANCA-positive vasculitis. Although fluoroquinolones have been reported to cause ANCA-negative leukocytoclastic vasculitis (LCV), fluoroquinolones are not known to induce proteinase 3-ANCA (PR3-ANCA)-positive vasculitis. Here, we present the case of a middle-aged man who developed severe headache, purpura on legs and numbness in hands and feet after taking ofloxacin for 5 days. Subsequently, he was diagnosed with ANCA-negative LCV and treated with steroids and immunosuppressants. Thirteen years later, he inadvertently received intravenous ciprofloxacin and developed severe headache and epistaxis. Serologic testing at that time revealed elevated titers of PR3-ANCA. Biopsy of nasal septum revealed a mixed mononuclear and polymorphonuclear infiltrate without evidence of granuloma formation. He was treated with steroids and immunosuppressive therapy. Over the next several years, he remained stable with residual hearing loss and nasal septal deformity. This case provides the first evidence for a PR3-ANCA-positive necrotizing vasculitis induced by ciprofloxacin
Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels
Electric discharge machining (EDM) is one of the most efficient manufacturing technologies used in highly accurate processing of all electrically conductive materials irrespective of their mechanical properties. It is a non-contact thermal energy process applied to a wide range of applications, such as in the aerospace, automotive, tools, molds and dies, and surgical implements, especially for the hard-to-cut materials with simple or complex shapes and geometries. Applications to molds, tools, and dies are among the large-scale initial applications of this process. Machining these items is especially difficult as they are made of hard-to-machine materials, they have very complex shapes of high accuracy, and their surface characteristics are sensitive to machining conditions. The review of this kind with an emphasis on tool and die materials is extremely useful to relevant professions, practitioners, and researchers. This review provides an overview of the studies related to EDM with regard to selection of the process, material, and operating parameters, the effect on responses, various process variants, and new techniques adopted to enhance process performance. This paper reviews research studies on the EDM of different grades of tool steel materials. This article (i) pans out the reported literature in a modular manner with a focus on experimental and theoretical studies aimed at improving process performance, including material removal rate, surface quality, and tool wear rate, among others, (ii) examines evaluation models and techniques used to determine process conditions, and (iii) discusses the developments in EDM and outlines the trends for future research. The conclusion section of the article carves out precise highlights and gaps from each section, thus making the article easy to navigate and extremely useful to the related research communit
Modelling of shrinkage formation in casting by the phase field method
Most commercial softwares simulating casting process use a scalar field to quantify the shrinkage on final parts. The
repartition of this scalar is used to localize shrinkage in the part. In this work, the objective is to use a new approach to predict
morphological information about size and shape of shrinkage: the phase field method. This method is based on a parameter
order defining the alternating zones metal/gas. Starting with a uniform unit value of this scalar, the phase field equation is
modified with a nucleation process predicting the growth of the air phase into the metal one still liquid. The coupling with
the Navier-Stokes equation brings up some interesting non-dimensional parameters that affect shrinkage morphology. This
is what we have tried to analyse after proposing the modified phase fields formalism. Even if we are not yet in the predictive
stage, we present in the end of this paper a numerical/experimental comparison showing the potentiality of the developed
approach
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