7,813 research outputs found

    Optimization of hot press forging parameters in direct recycling of aluminium chip (AA 6061)

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    This study introduces a new approach of direct recycling using the hot press forging process that eliminates the two intermediate processes of cold-compact and pre-heating. This method leads to low energy consumption without intervening the metallurgical processes. In this study, the optimum of machined chips from high speed milling is recycled by hot press forging. The mechanical properties and surface integrity of the different chips were investigated. The performance of recycled aluminium AA 6061 chips in the mechanical and physical properties were compared with the original aluminium billet. Response surface methodology (RSM) was used to develop mathematical model of the effects on pre-compaction cycle, holding time and suitable pressure significant to the process. It is hoped that, utilization of primary metal could be fully utilized by direct recycling technique (hot press forging) introduced in this study and at the same time developing a sustainable manufacturing process technology for future needs

    Soret and Dufour effects on unsteady mixed convection slip flow of Casson fluid over a nonlinearly stretching sheet with convective boundary condition

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    Unsteady mixed convection flow of Casson fluid towards a nonlinearly stretching sheet with the slip and convective boundary conditions is analyzed in this work. The effects of Soret Dufour, viscous dissipation and heat generation/absorption are also investigated. After using some suitable transformations, the unsteady nonlinear problem is solved by using Keller-box method. Numerical solutions for wall shear stress and high temperature transfer rate are calculated and compared with previously published work, an excellent arrangement is followed. It is noticed that fluid velocity reduces for both local unsteadiness and Casson parameters. It is likewise noticed that the influence of a Dufour number of dimensionless temperature is more prominent as compared to species concentration. Furthermore, the temperature was found to be increased in the case of nonlinear thermal radiation

    Business process modelling and visualisation to support e-government decision making: Business/IS alignment

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    © 2017 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/978-3-319-57487-5_4.Alignment between business and information systems plays a vital role in the formation of dependent relationships between different departments in a government organization and the process of alignment can be improved by developing an information system (IS) according to the stakeholders’ expectations. However, establishing strong alignment in the context of the eGovernment environment can be difficult. It is widely accepted that business processes in the government environment plays a pivotal role in capturing the details of IS requirements. This paper presents a method of business process modelling through UML which can help to visualise and capture the IS requirements for the system development. A series of UML models have been developed and discussed. A case study on patient visits to a healthcare clinic in the context of eGovernment has been used to validate the models

    Frequency of Predisposing Factor of Nausea and Vomiting After Chest Surgery Under General Anaesthesia

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    Background: Postoperative nausea and vomiting are common and distressing postsurgical symptoms. These symptoms are of particular concern in outpatient surgery because they may require additional direct resources, such as supplies and antiemetic drugs, and may delay discharge. The objective of this study was to measure the frequency of factors which can cause nausea and vomiting under general anaesthesia after chest surgery. Methodology: This descriptive case series evaluated frequency of predisposing factor of nausea and vomiting in patients of anaesthesia department of Gulab Devi Hospital Lahore. Questionnaire is made and patients were asked about their age, fever, previous surgery, NPO status, smoking history and hospital stay. This study included 140 patients with post-operative nausea and vomiting. Results: In this study, 140 patients were taken in which  65 (46.43%) were female and 75 (53.57%) were male. In 140 patient 134 (95.7%) were NPO and 6 (4.3%) were not  NPO, 25 (17.9%) were obese and 115 (82.1%) were not obese, 88 (62.9%) patients were suffering fever and 52 (37.1%) were not suffering fever, 80 (57.1%) were infected and 59 (42.1%) were not infected, 53 (37.9%) patients had previous surgery and 87 (62.1%) had no previous surgery, 94 (67.1%) patients had received nitrous oxide and 46 (32.9%) didn\u27t, 97 (69.3%) received volatile gases and 43 (30.7%) not received, 29 (20.7%) received ketamine and 111 (79.3%) not received, 87 (62.1%) received suxamethonium and 53 (37.9%) not received, 119 (85.0%) received propofol and 21 (15.0%) not received, 110 (78.6%) received naluphine and 28 (20.0%) not received. Out of 140 patients, there were 122 (87.1%) who were suffering from pain and 18 (12.9%) were not. 91 (65.0%) patients had gastric distention and 49 (35.0%) patients didn\u27t. Opioids were given to 34 (24.3%) patients and not given to 106 (75.7%) patient. Conclusion: It is concluded that the nausea and vomiting after surgey under genral anesthesia is due to patient related factors in which most frequent is NPO. Drug related factors include propofol and nalbupin administration. Post operative factors include pain. In whole study of 140 patients, the  most frequent is patient related factor (NPO) other than drug related factors and post-operative factors

    Coexisted Three-component Bosons and Two-component Weyl Bosons in TiS, ZrSe and HfTe

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    In analogy to various fermions of electrons in topological semimetals, topological mechanical states with two type of bosons, Dirac and Weyl bosons, were reported in some macroscopic systems of kHz frequency and those with a type of doubly-Weyl phonons in atomic vibrational framework of THz frequency of solid crystals were recently predicted. However, to date no three-component bosons of phonon has been reported. Here, through first-principles calculations, we have reported that the phonon spectra of the WC-type TiS, ZrSe, and HfTe commonly host the unique triply degenerate nodal points (TDNPs) and single two-component Weyl points (WPs) in THz frequency. Quasiparticle excitations near TDNPs of phonons are three-component bosons, beyond the conventional and known classifications of Dirac, Weyl and doubly-Weyl phonons. {Moreover, we have found that both TiS and ZrSe have five pairs of type-I Weyl phonons and a pair of type-II Weyl phonons, whereas HfTe only has four pairs of type-I Weyl phonons. They carry non-zero topological charges. On the (101ˉ\bar{1}0) crystal surfaces, we observe topological protected surface arc states connecting two WPs with opposite charges, which host modes that propagate nearly in one direction on the surface.Comment: 10 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1706.0687
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