230 research outputs found

    Correlation of p-doping in CVD Graphene with Substrate Surface Charges

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    Correlations between the level of p-doping exhibited in large area chemical vapour deposition (CVD) graphene field effect transistor structures (gFETs) and residual charges created by a variety of surface treatments to the silicon dioxide (SiO(2)) substrates prior to CVD graphene transfer are measured. Beginning with graphene on untreated thermal oxidised silicon, a minimum conductivity (σ(min)) occurring at gate voltage V(g) = 15 V (Dirac Point) is measured. It was found that more aggressive treatments (O(2) plasma and UV Ozone treatments) further increase the gate voltage of the Dirac point up to 65 V, corresponding to a significant increase of the level of p-doping displayed in the graphene. An electrowetting model describing the measured relationship between the contact angle (θ) of a water droplet applied to the treated substrate/graphene surface and an effective gate voltage from a surface charge density is proposed to describe biasing of V(g) at σ(min) and was found to fit the measurements with multiplication of a correction factor, allowing effective non-destructive approximation of substrate added charge carrier density using contact angle measurements

    Pengaruh Keberadaan Obyek Wisata Makam Dan Perpustakaan Bung Karno Terhadap Kondisi Ekonomi Masyarakat Pelaku USAha Perdagangan Di Sekitarnya

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    Makam Bung Karno sebagai daerah tujuan wisata unggulan terus berbenah dengan membangun Perpustakaan Bung Karno dan Museum Bung Karno. Tingginya jumlah kunjungan wisata menjadi peluang bagi masyarakat sekitar untuk menjadi pedagang. Tujuan penelitian ini adalah untuk mengetahui faktor pendorong masyarakat untuk bekerja sebagai pedagang, menyusun pengaruh keberadaan Makam Bung Karno terhadap masyarakat sekitar, serta menyusun arahan kebijakan pengembangan dan penataan kawasan wisata Makam Bung Karno. Penelitian ini menerapkan metode survey. Teknik analisis yang digunakan yakni analisis deskriptif, tabel frekuensi, perbandingan (paired sample T-Test), dan uji Wilcoxon. Hasil penelitian menunjukkan bahwa faktor utama yang mendorong masyarakat menjadi pedagang adalah faktor jarak, hal ini memang tidak terkait dengan wisata. Pembangunan Perpustakaan Bung Karno mampu membawa para pedagang pada kondisi kesejahteraan yang lebih baik, yaitu ditandai dengan peningkatan pendapatan rumah tangga; peningkatan keadaan tempat tinggal; peningkatan fasilitas tempat tinggal; peningkatan kehesatan keluarga; peningkatan kulitas pendidikan keluarga; dan peningkatan perasaan sejahtera

    Optimal Operation of Micro-grids Considering the Uncertainties of Demand and Renewable Energy Resources Generation

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    Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely connected to the low and medium voltage network and created a new structure called micro-grid. Renewable energies (especially wind and solar) based DGs are one of the most important generations units among DG units. Because of stochastic behavior of these resources, the optimum and safe management and operation of micro-grids has become one of the research priorities for researchers. So, in this study, the optimal operation of a typical micro-grid is investigated in order to maximize the penetration of renewable energy sources with the lowest operation cost with respect to the limitations for the load supply and the distributed generation resources. The understudy micro-grid consists of diesel generator, battery, wind turbines and photovoltaic panels. The objective function comprises of fuel cost, start-up cost, spinning reserve cost, power purchasing cost from the upstream grid and the sales revenue of the power to the upstream grid. In this paper, the uncertainties of demand, wind speed and solar radiation are considered and the optimization will be made by using the GAMS software and mixed integer planning method (MIP).Article History: Received May 21, 2016; Received in revised form July 11, 2016; Accepted October 15, 2016; Available onlineHow to Cite This Article: Jasemi, M., Adabi, F., Mozafari, B., and Salahi, S. (2016) Optimal Operation of Micro-grids Considering the Uncertainties of Demand and Renewable Energy Resources Generation, Int. Journal of Renewable Energy Development, 5(3),233-248.http://dx.doi.org/10.14710/ijred.5.3.233-24

    Goiter frequency is more strongly associated with gastric adenocarcinoma than urine iodine level

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    Purpose: We designed our study to evaluate the hypothesis that gastric cancer is correlated with iodine deficiency or thyroid dysfunction. Materials and Methods: We investigated the total body iodine reserve, thyroid function status and autoimmune disorder in 40 recently diagnosed gastric adenocarcinoma cases versus 80 healthy controls. The participants came from a region with high gastric cancer rate but sufficient iodine supply due to salt iodination. The investigation included urine iodine level, thyroid gland clinical and ultrasonograph-ic examination, and thyroid function tests. Results: Goiter was detected more frequently in the case group (P=0.001); such a finding, however, was not true for lower than normal urine iodine levels. The free T3 mean level was significantly lower in the case group compared to the control group (P=0.005). Conclusions: The higher prevalence of goiter rather than low levels of urinary iodine in gastric adenocarcinoma cases suggests that goi-ter, perhaps due to protracted but currently adjusted iodine deficiency, is more likely to be associated with gastric adenocarcinoma com-pared to the existing iodine deficiency itself. © 2013 by The Korean Gastric Cancer Association

    A Fuzzy Logic Based Approach in Choosing the Appropriate Physical Machines for Live Virtual Machines Migration in Cloud Computing

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    Migration of Virtual Machine (VM) has become a critical issue in modern data centers that are working based on virtualization. Among VM Migration challenges, choosing an appropriate Physical Machine (PM) is an important issue. To choose a place for VM several parameters, such as physical topology, migration duration, power consumption, service continuity, and price must be considered. Finding a near optimal place for VM migration that trades-off between some or all of these features is a challenging problem. In this paper, we propose three aspects for ranking potential destination PMs to find the most appropriate PM as VM host. In the first aspect, PMs are ranked in terms of servicing condition using Fuzzy logic technique according to three parameters: workload, performance efficiency and availability. In the second aspect, PMs are ranked in terms of power consuming condition using Fuzzy logic technique according to power, temperature efficiency and power efficiency metrics. In the third aspect, the output of two fuzzy logic engines with communication cost metric is used as the third fuzzy logic engine inputs that rank PMs. The proposed technique has been compared with AppAware algorithm in terms of communication cost and performance efficiency. Experimental results demonstrate that the proposed technique has appropriate improvement in these metrics and outperforms AppAware algorith

    Degradation of phenol using US/periodate/nZVI system from aqueous solutions

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    In the present work, the degradation of phenol from aqueous solutions was investigated using periodate/zero valent iron nanoparticle (nZVI) in the presence of ultrasound at a batch reactor. The Experimental tests were carried out using pre-designated concentrations of nZVI, periodate, and pH ranging from 1-7 mM, 0.5-5 mM, 3-11 respectively. During the all experimental tests the ultrasonic reactor was operated at a fix frequency (40 kHz), temperature (33±1) and power (350 W). The results of nZVI/periodate/ultrasound system on degradation of phenol showed that the removal efficiency was indeed affected by the amount of free radicals produced to initiate the oxidative decomposition of phenol. also, by increasing the nZVI loading to 3 mM and periodate concentration to 3 mM, the efficiency of phenol removal was increased. Besides, the acidic pH (pH = 3) was found to be more effective than neutral and alkaline pH in degradation of phenol. © 2019 Global NEST Printed in Greece. All rights reserved

    Spread of efflux pump overexpressing-mediated fluoroquinolone resistance and multidrug resistance in Pseudomonas aeruginosa by using an efflux pump inhibitor

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    Background: Fluoroquinolone resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression and/or target mutations. We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections. Materials and Methods: A total of 154 consecutive strains of P. aeruginosa were recovered from separate patients hospitalized in a burn hospital, Tehran, Iran. The isolates first were studied by disk diffusion antibiogram for 11 antibiotics and then minimum inhibitory concentration (MIC) experiments were performed to detect synergy between ciprofloxacin and the efflux pump inhibitor, carbonyl cyanide-m-chlorophenyl hydrazone (CCCP). Then to elucidate the inducing of multi drug resistance due to different efflux pumps activation in Fluoroquinolone resistant isolates, synergy experiments were also performed in random ciprofloxacin resistant isolates which have overexpressed efflux pumps phenotypically, using CCCP and selected antibiotics as markers for Beta-lactams and Aminoglycosides. The isolates were also tested by polymerase chain reaction (PCR) for the presence of the MexA, MexC and MexE, which encode the efflux pumps MexAB-OprM, MexCD-OprJ and MexEF-OprN. Results: Most of the isolates were resistant to 3 or more antibiotics tested. More than half of the ciprofloxacin resistant isolates exhibited synergy between ciprofloxacin and CCCP, indicating the efflux pump activity contributed to the ciprofloxacin resistance. Also increased susceptibility of random ciprofloxacin resistant isolates of P. aeruginosa to other selected antibiotics, in presence of CCCP, implied multidrug extrusion by different active efflux pump in fluoroquinolones resistant strains. All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously. Conclusion: In this burn hospital, where multidrug resistant P. aeruginosa isolates were prevalent, ciprofloxacin resistance and multidrug resistance due to the overexpression of fluoroquinolones mediated efflux pumps has also now emerged. Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy. © 2015 by The Korean Society of Infectious Diseases

    Cloud service brokerage: Exploring characteristics and benefits of B2B cloud marketplaces

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    With the increasing popularity of cloud computing, a new technology and business model called cloud service brokerage (CSB) is emerging. CSB is, in essence, a middleman in the cloud-computing supply chain to connect prospective cloud buyers with suitable service providers. This chapter focuses on a type of CSB, B2B cloud marketplaces. Recently, this type of marketplace has evolved into two broad categories—business application marketplaces and API marketplaces. This chapter reviews the characteristics of B2B cloud marketplaces, and their benefits, which include ease-of-use and ease-of-integration, enhanced security, increased manageability, faster implementation, and cost reduction. The chapter concludes with two mini-case studies, on Salesforce AppExchange and RapidAPI, to illustrate how firms could use B2B cloud marketplaces to generate, capture and measure business value

    Influence of field-dependent critical current on harmonic AC loss analysis in HTS coils for superconducting transformers supplying non-linear loads : harmonic analysis of HTS transformers

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    There are two main obstacles in front of the development of high temperature superconducting (HTS) technology for electric power network applications; tape price and cooling cost. In order to reduce cooling cost, it is vital to evaluate AC transport current loss of the tapes precisely and then reduce it by some design innovative approaches. In addition, AC transport current loss in HTS material is a critical design variable for large-scale power network applications such as HTS transformers, superconducting fault current limiters, and power cables, since they are continuously carrying the network/load current during their operating life. In existing power networks, harmonic production sources are commonly used and thus, currents are distorted. Therefore, the effect of nonsinusoidal current on the critical apparatus in the network such as transformer must be studied. In this paper, AC transport current loss of a single-turn 2G YBCO HTS coil was modeled and numerically calculated under nonsinusoidal transport current using finite element method. Furthermore, influence of dependency of critical current density to magnetic field on the AC transport current loss of HTS coil when carries distorted currents was considered. It was observed that nonsinusoidal current causes excessive losses in HTS coil. On the other hand, a case study on an HTS transformer supplying non-linear load was considered to study the loss increment as well as heat load change. It was observed that current harmonics increases the AC loss, and heat load of transformer and decreases the efficiency, consequently
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