710 research outputs found

    Comparative study between cold leg and hot leg safety injection during SBLOCA in a 4-loop PWR NPP

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    This article presents a comparison between two operation modes for the emergency core cooling system during a Small Break Loss of Coolant Accident (SBLOCA) in the cold leg of 4-loop PWR Westinghouse design nuclear power plant. In the first mode, the cold leg safety injection is used to mitigate the consequences of the accident and in the second mode the hot leg safety injection is used. The best estimate light water reactor transient analysis system code RELAP5 Mod3.3 was used in calculations. The plant nodalization consists of two loops; the first one represents the broken loop and the second one represents the other three intact loops. The results show that, in the cold leg safety injection the primary pressure decreases with time and remains higher than the secondary pressure for a period of time (~ 500 sec) during whichthe steam generators remains as a heat sink for the primary side, the accumulators start late and functioning on remaining transient time, and a repeatable loop seal clearing and refill occurs. During the hot leg safety injection the primary pressure decreases rapidly but remains higher than the secondary pressure for a longer period of time (~ 600 sec), the accumulators start early and functioning on a part of the transient time before they are totally discharged, and there is no repeatable loop seal clearing and refill. In the two modes the maximum clad surface temperature does not violate the safety limit

    Hubungan Kompetensi Penyuluh Dengan Karakteristik Pribadi, Persepsi Penyuluh Terhadap Dukungan Kelembagaan Dan Persepsi Penyuluh Terhadap Sifat Inovasi Cyber Extensión

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    EnglishCyber extension may empower agricultural extension workers through preparation of timely and relevant agricultural information in supporting decision making process to deliver information to the farmers. Many factors affect use of information technology. This study aims to analyze correlation among the extension workers' characteristics and perceptions towards institutional support with the extension workers' perceptions of innovation nature and the extension workers' competence in cyber extension use. The research uses the Spearman rank correlation (rs) for the analysis. Locations of study were carried out in the Regencies of Kuningan and Bekasi, West Java Province. Data were collected from October to December 2012.The results show that the extension workers' competence in using cyber extension have significant correlation with the extension workers' characteristic, i.e. age variable (rs = 0.114*). Perception on cyber extension innovation nature has a significant correlation with the extension workers' perception on the institutional support (rs = 0.371**). Competence in using cyber extension has a significant correlation with the extension workers' perceptions on institutional support (rs=0.19**). It is necessary to conduct some activities, i.e., mapping of agricultural extension workers' ability, designing cyber extension training for agricultural extension workers, implementing the field days for cyber extension utilization in Agricultural Extension Centers in regency level, building networks, and improving infrastructure of cyber extension facilities.IndonesianCyber extension dapat meningkatkan keberdayaan penyuluh melalui penyiapan informasi pertanian yang tepat waktu, dan relevan dalam mendukung proses pengambilan keputusan penyuluh, guna penyampaian data dan informasi pertanian kepada petani dan kelompok taninya. Permasalahannya adalah banyak faktor yang memengaruhi dalam pemanfaatan teknologi informasi tersebut, Penelitian ini bertujuan untuk menganalisis hubungan antara karakteristik penyuluh, persepsi penyuluh terhadap dukungan kelembagaan dengan persepsi penyuluh terhadap sifat inovasi cyber extension dan kompetensi penyuluh dalam pemanfaatan cyber extensión. Penelitian menggunakan pendekatan kuantitatif untuk mencari hubungan antar peubah, dengan metode sensus menggunakan korelasi Rank Spearman (rs). Lokasi penelitian Kabupaten Kuningan dan Bekasi, Provinsi Jawa Barat, dan waktu penelitian dilaksanakan bulan Oktober sampai Desember 2012. Hasil penelitian menunjukkan hubungan nyata kompetensi penyuluh dalam pemanfaatan cyber extension dengan karakteristik penyuluh melalui indikator umur (rs= 0,114*). Persepsi penyuluh terhadap sifat inovasi cyber extension mempunyai hubungan nyata dengan persepsi penyuluh terhadap dukungan kelembagaan sebesar (rs= 0,371**). Kompetensi penyuluh dalam pemanfaatan cyber extension mempunyai hubungan nyata dengan persepsi penyuluh terhadap dukungan kelembagaan sebesar (rs= 0,19**). Kesimpulan adalah terdapat hubungan nyata antara karakteristik penyuluh dan persepsi penyuluh terhadap dukungan kelembagaan dengan persepsi penyuluh terhadap sifat inovasi cyber extension, dan terdapat hubungan nyata antara persepsi penyuluh terhadap sifat inovasi dengan kompetensi penyuluh dalam pemanfaatan cyberextension. Terdapat hubungan nyata antara karakteristik penyuluh dan pesepsi penyuluh terhadap dukungan kelembagan dengan kompetensi penyuluh dalam pemanfaatan cyber extension. Saran adalah membuat klasifikasi atau pemetaan terhadap kemampuan penyuluh, merancang pelatihan, membuka hari lapangan pemanfaatan cyber extension di Balai Penyuluhan Pertanian Kecamatan, membangun jejaring kerjasama, dan meningkatkan fasilitasi sarana prasarana cyber extension

    Characteristics of the channels and blood parameters of chickens complemented with chromium and their productive acting

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    P?ginas 15-19Recurso Electr?nicoEl presente trabajo evalu? el efecto del cromo en dietas para pollo de engorde con diferentes niveles de inclusi?n. Se evalu? : peso inicial, peso final, ganancia de peso, conversi?n, consumo, rendimiento en canal, peso de alas, pechuga, pernil, colesterol, glicemia y HDL. Se emplearon 96 aves distribuidas en 4 tratamientos con 4 repeticiones y 6 aves en cada una, alimentadas con cromo a partir del d?a noveno de vida hasta el d?a 35. Los tratamientos 1, 2, 3, y 4 conten?an cromo en 0ppm, 0,5 ppm, 1 ppm, y 1,5 ppm en la dieta respectivamente. No se encontraron diferencias significativas (p0,05) en el consumo de alimento. Pese a lo anterior los mejores resultados obtenidos se presentaron en los tratamientos 2. Peso final (1983.3 g vs 2032,3 g), ganancia de peso (1811,9 g vs 1859,9 g ), conversi?n (1,666 vs 1,670). Con respecto al consumo el tratamiento control presento consumo m?s bajo (3305 g vs 3395 g), y rendimiento en canal el tratamiento control presento mejor rendimiento con respecto a los dem?s tratamientos (71,8 % vs 71,3 %). Con respecto a los cortes los resultados favorecen a los tratamientos con cromo, alas (172,9 g vs 181,5 g), pechugas (536,3 g vs 545,1 g), perniles (699,1 g vs 708,6 g). Se determin? que el tratamiento 2 presenta los mejores resultados econ?micos.ABSTRACT. This project aims to evaluate the effect of chromium in breeding chicken diets with different inclusion levels. The items evaluated were: initial weight, final weight, increase in weight, conversion, consumptions, carcass development, wings, breasts, and legs weight, cholesterol, blood sugar, and HDL. A sample of 96 birds was used distributed in 4 treatments with 4 repetitions and 6 birds each, fed with chromium since the 9th day of life until day 35. Treatments 1, 2, 3 and 4 had chromium concentrations of 0 ppm, 0,5 ppm, 1 ppm, and 1,5 ppm in their diet respectively. No significant differences were found (p0,05) was food consumption. Nevertheless, the best results were found in birds subjected to treatment 2: Final weight (1983,3 g vs. 2032,3 g), increase in weight (1811,9 g vs. 1859,9 g), and conversion (1.666 vs. 1.670). Regarding consumption, the control treatment presented the lowest rate (3305 g vs. 3395 g); and regarding yield in channel, the control treatment presented better outputs than the others (71,8 % vs 71,3 %). Examining other criteria, outputs favor chromium treatments: wings (172,9 g vs. 181,5 g), breasts (536,3 g vs. 545,1 g), and legs (669,1 g vs. 708,6 g). Therefore, it was determined that treatment 2 brings better economic results

    Strontium and Oxygen Isotope Analyses Reveal Late Cretaceous Shark Teeth in Iron Age Strata in the Southern Levant

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    Skeletal remains in archaeological strata are often assumed to be of similar ages. Here we show that combined Sr and O isotope analyses can serve as a powerful tool for assessing fish provenance and even for identifying fossil fish teeth in archaeological contexts. For this purpose, we established a reference Sr and O isotope dataset of extant fish teeth from major water bodies in the Southern Levant. Fossil shark teeth were identified within Iron Age cultural layers dating to 8–9th century BCE in the City of David, Jerusalem, although the reason for their presence remains unclear. Their enameloid 87Sr/86Sr and δ18OPO4 values [0.7075 ± 0.0001 (1 SD, n = 7) and 19.6 ± 0.9‰ (1 SD, n = 6), respectively], are both much lower than values typical for modern marine sharks from the Mediterranean Sea [0.7092 and 22.5–24.6‰ (n = 2), respectively]. The sharks’ 87Sr/86Sr are also lower than those of rain- and groundwater as well as the main soil types in central Israel (≥0.7079). This indicates that these fossil sharks incorporated Sr (87Sr/86Sr ≈ 0.7075) from a marine habitat with values typical for Late Cretaceous seawater. This scenario is in line with the low shark enameloid δ18OPO4 values reflecting tooth formation in the warm tropical seawater of the Tethys Ocean. Age estimates using 87Sr/86Sr stratigraphy place these fossil shark teeth at around 80-million-years-old. This was further supported by their taxonomy and the high dentine apatite crystallinity, low organic carbon, high U and Nd contents, characteristics that are typical for fossil specimens, and different from those of archaeological Gilthead seabream (Sparus aurata) teeth from the same cultural layers and another Chalcolithic site (Gilat). Chalcolithic and Iron Age seabream enameloid has seawater-like 87Sr/86Sr of 0.7091 ± 0.0001 (1 SD, n = 6), as expected for modern marine fish. Fossil shark and archaeological Gilthead seabream teeth both preserve original, distinct enameloid 87Sr/86Sr and δ18OPO4 signatures reflecting their different aquatic habitats. Fifty percent of the analysed Gilthead seabream teeth derive from hypersaline seawater, indicating that these seabreams were exported from the hypersaline Bardawil Lagoon in Sinai (Egypt) to the Southern Levant since the Iron Age period and possibly even earlier

    Achieving Longevity in Wireless Body Area Network by Efficient Transmission Power Control for IoMT Applications

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    The application of tiny body sensors to collect, process, store, analyze, and retrieve medical information from a human body is a part of the Internet of Medical Things (IoMT).  IoMT helps to monitor and track human vital health parameters, predict disease, notify the patients and the health care professionals with relevant data for analyzing the problems before they become severe and for earlier invention. By 2022, more than 60 % of IoT applications will be health-related. The convergence of biomedical sensors, wireless body area networks (WBAN), Information technology, and bioinformatics will help improve the efficiency of saving human lives. In a WBAN, network longevity is challenging because of the limited supply of low power battery energy in tiny body sensor nodes. Here, we proposed an energy-efficient transmission power control (TPC) algorithm to extend the network lifetime in IoMT networks for healthcare applications by eliminating the transceiver overhearing problem. In TPC, human tissue resistivity properties are considered to adjust the transmission power, which reduces the communication power and extends the network lifetime. The simulation results show that network power consumption is reduced by 35%

    Modulational instability in periodic quadratic nonlinear materials

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    We investigate the modulational instability of plane waves in quadratic nonlinear materials with linear and nonlinear quasi-phase-matching gratings. Exact Floquet calculations, confirmed by numerical simulations, show that the periodicity can drastically alter the gain spectrum but never completely removes the instability. The low-frequency part of the gain spectrum is accurately predicted by an averaged theory and disappears for certain gratings. The high-frequency part is related to the inherent gain of the homogeneous non-phase-matched material and is a consistent spectral feature.Comment: 4 pages, 7 figures corrected minor misprint

    The potential use of service-oriented infrastructure framework to enable transparent vertical scalability of cloud computing infrastructure

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    Cloud computing technology has become familiar to most Internet users. Subsequently, there has been an increased growth in the use of cloud computing, including Infrastructure as a Service (IaaS). To ensure that IaaS can easily meet the growing demand, IaaS providers usually increase the capacity of their facilities in a vertical IaaS increase capability and the capacity for local IaaS amenities such as increasing the number of servers, storage and network bandwidth. However, at the same time, horizontal scalability is sometimes not enough and requires additional strategies to ensure that the large number of IaaS service requests can be met. Therefore, strategies requiring horizontal scalability are more complex than the vertical scalability strategies because they involve the interaction of more than one facility at different service centers. To reduce the complexity of the implementation of the horizontal scalability of the IaaS infrastructures, the use of a technology service oriented infrastructure is recommended to ensure that the interaction between two or more different service centers can be done more simply and easily even though it is likely to involve a wide range of communication technologies and different cloud computing management. This is because the service oriented infrastructure acts as a middle man that translates and processes interactions and protocols of different cloud computing infrastructures without the modification of the complex to ensure horizontal scalability can be run easily and smoothly. This paper presents the potential of using a service-oriented infrastructure framework to enable transparent vertical scalability of cloud computing infrastructures by adapting three projects in this research: SLA@SOI consortium, Open Cloud Computing Interface (OCCI), and OpenStack

    Nonlinear localized waves in a periodic medium

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    We analyze the existence and stability of nonlinear localized waves in a periodic medium described by the Kronig-Penney model with a nonlinear defect. We demonstrate the existence of a novel type of stable nonlinear band-gap localized states, and also reveal an important physical mechanism of the oscillatory wave instabilities associated with the band-gap resonances.Comment: 4 pages, 5 figure
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