538 research outputs found

    The indivisibility of the homogeneous Kn-free graphs

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    AbstractWe will prove that for each n ≥ 3 the homogeneous Kn-free graph Hn is indivisible. That means that for every partition of Hn into two classes R and B there is an isomorphic copy of Hn in R or in B. This extends a result of Komjáth and Rödl [Graphs Combin., 2 (1986), 55–60] who have shown that H3 is indivisible

    Implementation of biological routing protocol in Tunnel Wireless Sensor Network (TWSN)

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    A routing protocol is a core issue in Wireless Sensor Network (WSN) especially on undetermined situation and crucial condition to guarantee the transmission of data. Therefore, any implementation of routing protocol in a tunnel environment will suit with their application to minimize dropped data in its communication. This paper presents a biological routing protocol named as Biological Tunnel Routing Protocol (BioTROP) in Tunnel Wireless Sensor Network (TWSN). BioTROP has been tested with four challenging situations for marking its standard soon. By setting it in low power transmission, all nodes appear as source node and intermediate nodes concurrently, faster transmission rate and free-location setup for each node; these conditions make BioTROP as an ad-hoc protocol with lightweight coding size in tunnel environment. This protocol is tested only in real test bed experiment using 7 TelosB nodes at a predetermined distance. The results have shown more than 70 percent of the transmitted data packets were successfully delivered at the base station

    Approaches of Finite Element Analysis to Study Fatigue Analysis of Rail-Wheel Contact for Light Rail Transit

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    Rolling contact fatigue (RCF) is one of the main rail failure due of repeated stresses at rail-wheel contact. The types of defects of RCF such as spalling, squat and head checking occur at surface of rail as possible lead to catastrophic for train derailment. As to reduce the cost of maintenance in using preventative maintenance than corrective maintenance where it crucial to predict the rail fatigue failure through simulation. The objective of this research paper was to predict the cracks at rail surface in 3-dimensional through finite element analysis and in compared results with Hertz theory, also to count circles of fatigue failure with 80000 N against rail. The rail profile selection was R260 as standard rail for light rapid transit. Results demonstrated that the highest von mises stress located at contact patch of rail-wheel, different percent of von mises stress & contact pressure and predicted the rail fatigue regards 339300 circles. Furthermore, this research study has not yet reported and discussed in previous studies for light rapid transit. &nbsp

    Approaches of Finite Element Analysis to Study Fatigue Analysis of Rail-Wheel Contact for Light Rail Transit

    Get PDF
    Rolling contact fatigue (RCF) is one of the main rail failure due of repeated stresses at rail-wheel contact. The types of defects of RCF such as spalling, squat and head checking occur at surface of rail as possible lead to catastrophic for train derailment. As to reduce the cost of maintenance in using preventative maintenance than corrective maintenance where it crucial to predict the rail fatigue failure through simulation. The objective of this research paper was to predict the cracks at rail surface in 3-dimensional through finite element analysis and in compared results with Hertz theory, also to count circles of fatigue failure with 80000 N against rail. The rail profile selection was R260 as standard rail for light rapid transit. Results demonstrated that the highest von mises stress located at contact patch of rail-wheel, different percent of von mises stress & contact pressure and predicted the rail fatigue regards 339300 circles. Furthermore, this research study has not yet reported and discussed in previous studies for light rapid transit. &nbsp

    Rapid antigen testing as a reactive response to surges in nosocomial SARS-CoV-2 outbreak risk

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    Healthcare facilities are vulnerable to SARS-CoV-2 introductions and subsequent nosocomial outbreaks. Antigen rapid diagnostic testing (Ag-RDT) is widely used for population screening, but its health and economic benefits as a reactive response to local surges in outbreak risk are unclear. We simulate SARS-CoV-2 transmission in a long-term care hospital with varying COVID-19 containment measures in place (social distancing, face masks, vaccination). Across scenarios, nosocomial incidence is reduced by up to 40-47% (range of means) with routine symptomatic RT-PCR testing, 59-63% with the addition of a timely round of Ag-RDT screening, and 69-75% with well-timed two-round screening. For the latter, a delay of 4-5 days between the two screening rounds is optimal for transmission prevention. Screening efficacy varies depending on test sensitivity, test type, subpopulations targeted, and community incidence. Efficiency, however, varies primarily depending on underlying outbreak risk, with health-economic benefits scaling by orders of magnitude depending on the COVID-19 containment measures in place

    Bringing COVID-19 home for Christmas: a need for enhanced testing in healthcare institutions after the holidays

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    Festive gatherings this 2020 holiday season threaten to cause a surge in new cases of novel coronavirus disease 2019 (COVID-19). Hospitals and long-term care facilities are key hotspots for COVID-19 outbreaks, and may be at elevated risk as patients and staff return from holiday celebrations in the community. Some settings and institutions have proposed fortified post-holiday testing regimes to mitigate this risk. We use an existing model to assess whether implementing a single round of post-holiday screening is sufficient to detect and manage holiday-associated spikes in COVID-19 introductions to the long-term care setting. We show that while testing early helps to detect cases prior to potential onward transmission, it likely to miss a substantial share of introductions owing to false negative test results, which are more probable early in infection. We propose a two-stage post-holiday testing regime as a means to maximize case detection and mitigate the risk of nosocomial COVID-19 outbreaks into the start of the new year. Whether all patients and staff should be screened, or only community-exposed patients, depends on available testing capacity: the former will be more effective, but also more resource-intensive

    Détection de l'adultération du beurre par la margarine

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    Une méthode analytique permettant de détecter l’adultération du beurre par la margarine a été développée. Elle est basée sur la détermination de la composition en acides gras et en stérols par chromatographie en phase gazeuse. Plusieurs niveaux d’adultération du beurre par la margarine (3, 5 et 10% p/p) ont été préparés puis analysés. Les résultats montrent que l’acide linoléique et les stérols permettent de détecter la margarine dans le beurre à un seuil de 3%

    Pembekalan Materi Pembelajaran Pemberaian Batuan (Rock Excavation) Di Smk Muhammadiyah Jurusan Geologi Pertambangan Kota Jambi

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    SMK Muhammadiyah Kota Jambi adalah sebuah sekolah menengah kejuruan swasta yang berdiri pada tanggal 27 Maret 2014. SMK ini berlokasi di Jl, Guntur No.2 Rt.8, Kelurahan Kasang, Kec. Jambi Timur, Kota Jambi. Status SMK Muhammadiyah Kota Jambi saat ini belum terakreditasi dan sedang dalam tahap pengajuan. Sedangkan kurikulum pembelajaran yang dipakai yaitu KTSP (Kurikulum Tingkat Satuan Pendidikan). SMK memiliki dua jurusan utama yakni perbankan syariah dan geologi pertambangan.Permasalahan yang di hadapi SMK Muhammadiyah yakni belum terakreditasinya sekolah, Sarana dan prasarana yang belum memadai, terutama yang berkaitan langsung dengan proses belajar mengajar, diantaranya: laboratorium, sampel batuan dan mineral, alat ukur dan gps, dll, Kurangnya jumlah guru yang memiliki kompetensi di bidang pertambangan . Belum adanya kerjasama dengan stakeholder terkait, misalnya SMK Geologi/ Pertambangan lain, universitas, maupun instansi dan perusahaan yang berkaitan dengan Pertambangan, Kurangnya kegiatan kunjungan lapangan. Program Studi Teknik Pertambangan Universitas Jambi dalam kapasitasnya sebagai institusi pendidikan tinggi yang rgerak di bidang pertambangan berniat untuk berkontribusi dan bekerjasama dengan pihak SMK Muhammadiyah Jambi untuk menjawab permasalahan rendahnya kualitas proses belajar mengajar, khususnya pada jurusan Geologi Pertambangan, dengan program pengabdian kepada masyarakat yang berjudul “Pembekalan Materi Pembelajaran Pemberaian Batuan (Rock Excavation) di SMK Muhammadiyah Jurusan Geologi Pertambangan”. dengan hasil akhir kegiatan pengabdian yakni buku ajar dan jurnal ilmiah

    Effect of storage temperature on the keeping quality of commercially pasteurized milk

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    Pour étudier l'effet de la température sur la durée de conservation du lait pasteurisé, du lait fraîchemf:'nt pasteurisé et non homogénéisé provenant de deux laiteries industrielles, a été conservé à 7 et à 25°C. L'évolution du pH, des caractéristiques sensorielles, et de la flore totale du lait a été étudiée durant la période de conservation. L'altération du lait dont le taux microbien initial était de 10 3 UFC/ml a été observée entre le 5 ème et 6ème jour de conservation à 7°C. A 25°C, cette durée n'a été que de 20 à 24 heures. Au début de l'altération, le taux microbien a dépassé 10 7 UFC/ml. Les deux laits ont montré les mêmes signes d'altération à savoir la putréfaction, l'amertume, le caractère fruité, et la rancidité à 7°C; tandis qu'à 25°C, les défauts détectés étaient l'acidité, le surissement, et la rancidité. Les échantillons de lait ont montré également le signe de coagulation après ébullition, 2 heures avant l'altération à 25°C alors qu'à 7°C la coagulation du lait a eu lieu le même jour du début de l'altération. To study the effect of temperature on the shelf-life, freshly pasteurized and unhomogenized whole milk from two dairy plants was stored at 7 and 25°C. Microbial, sensory, and pH changes were monitored during storage. Milk of 1000 CFU/ml, as initial microbial count, showed evidence of spoilage between 5th and 6th day of storage at 7°C. When stored at 25°C, the shelf-life was only 20 to 24 hours. The microbial count at the time of spoilage exceeded 10000000 CFU/ml. Both brands ofmilk showed similar spoilage characteristics of putrid, bitter, fruity and rancid at 7°C and acid, sour, and rancid defects at 25°C. Milk samples showed clotting on boiling 2 hours before evidence of spoilage at 25°C and simultaneously with spoilage at 7°C

    Préparation du fromage frais à partir du lait recombiné

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    Le but de cette étude a été d'évaluer les possibilités de préparation du fromage frais à partir du lait recombiné qui a été pasteurisé puis conservé pendant une nuit à 6°C pour faciliter la réhydratation. Le lait a été ensuite inoculé avec le levain constitué à parts égales de L. lactis subsp. lactis, L. lactis subsp. lactis var. diacetylactis et L. casei subsp casei à raison de 3% puis maintenu entre 30 et 37°C pour activer la fermentation. À pH 5,0 à 5,5, la présure a été ajoutée puis le moulage a été réalisé à température ambiante lorsque le pH a atteint une valeur comprise entre 4,3 .. 5,0. L'adoption de cette procédure normalisée de préparation du fromage frais a donné lieu à des produits de composition physico-chimique régulière et de qualité microbiologique satisfaisante. L'analyse sensorielle du fromage frais a montré que les produits élaborés à partir du lait recombiné uniquement (100%), ont été moins appréciés que ceux préparés à partir du lait recombiné additionné de 25 ou 50% de lait frais.Manufacture of fresh cheese from recombined milkThis study was carried out to evaluate the possibility of making fresh cheese from recombined milk. For this preparation, recombined milk was pasteurized and cooled overnight at 6°C to improve the powder rehydration. Then, milk was inoculated with 3% of a lactic starter composed of L.lactis subsp. lactis, L. lactis subsp.lactis var. diacetylactis and L. ca sei subsp. casei, and kept at 30 - 3TC to activate fermentation. At pH 5,0 - 5,5, the rennet was added and moulding was realized at ambient temperature when the pH reached a value of 4,3 to 5,0. Standardization of the processing gave fresh cheese with a regular chemical composition and a satisfactory microbiological quality. The sensory evaluation of fresh cheese showed that the products made with 100% recombined milk were less appreciated than those prepared from recombined milk added up with 20 to 25% fresh milk
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