WorldWideScience

Sample records for coralyne-induced homo-adenine duplex

  1. Vesicoureteral Reflux and Duplex Systems

    OpenAIRE

    Thomas, John C.

    2008-01-01

    Vesicoureteral reflux (VUR) is the most common anomaly associated with duplex systems. In addition to an uncomplicated duplex system, reflux can also be secondary in the presence of an ectopic ureterocele with duplex systems. Controversy exists in regard to the initial and most definitive management of these anomalies when they coexist. This paper will highlight what is currently known about duplex systems and VUR, and will attempt to provide evidence supporting the various surgical approa...

  2. The Duplex Society.

    Science.gov (United States)

    Schorr, Alvin L.

    1984-01-01

    The duplex society, in which the poor live in close proximity to others but in a separate compartment, is already with us. Unless something deeply changes about family income, more than one-third of future generations will come to adulthood having spent a portion of their childhood in official poverty. (RM)

  3. Duplex tab exhaust nozzle

    Science.gov (United States)

    Gutmark, Ephraim Jeff (Inventor); Martens, Steven (nmn) (Inventor)

    2012-01-01

    An exhaust nozzle includes a conical duct terminating in an annular outlet. A row of vortex generating duplex tabs are mounted in the outlet. The tabs have compound radial and circumferential aft inclination inside the outlet for generating streamwise vortices for attenuating exhaust noise while reducing performance loss.

  4. Considerations in Duplex Investment.

    Science.gov (United States)

    Wright, Arthur; Goen, Tom

    Problems of duplex investment are noted in the introduction to this booklet designed to provide a technique by which the investment decision can be approached, develop estimates of typical costs and returns under differing conditions, and encourage investors to analyze objectives and conditions before the decision to buy or build is made. A…

  5. Maximizing synchronizability of duplex networks

    Science.gov (United States)

    Wei, Xiang; Emenheiser, Jeffrey; Wu, Xiaoqun; Lu, Jun-an; D'Souza, Raissa M.

    2018-01-01

    We study the synchronizability of duplex networks formed by two randomly generated network layers with different patterns of interlayer node connections. According to the master stability function, we use the smallest nonzero eigenvalue and the eigenratio between the largest and the second smallest eigenvalues of supra-Laplacian matrices to characterize synchronizability on various duplexes. We find that the interlayer linking weight and linking fraction have a profound impact on synchronizability of duplex networks. The increasingly large inter-layer coupling weight is found to cause either decreasing or constant synchronizability for different classes of network dynamics. In addition, negative node degree correlation across interlayer links outperforms positive degree correlation when most interlayer links are present. The reverse is true when a few interlayer links are present. The numerical results and understanding based on these representative duplex networks are illustrative and instructive for building insights into maximizing synchronizability of more realistic multiplex networks.

  6. Welding of duplex and super-duplex stainless steels

    International Nuclear Information System (INIS)

    Van Nassau, L.; Meelker, H.; Hilkes, J.

    1994-01-01

    After a recall of the commercial designation of duplex or super-duplex steels (22-27% Cr, 4-8% Ni, 0.1-0.3% N with or without Mo (1.5-4%)) and of some metallurgical properties (phase diagrams, microstructure, ferrite determination, heat treatment and aging), welding technologies are synthetically presented (advantages-disadvantages of each process, metals filler, parameters of the welding processes, heat treatments after welding, cleaning, passivation, properties (mechanical, corrosion resistance) of the welded pieces). (A.B.). 28 refs. 5 figs., 15 tabs., 1 annexe

  7. Achieving single channel, full duplex wireless communication

    KAUST Repository

    Choi, Jung Il; Jain, Mayank; Srinivasan, Kannan; Levis, Phil; Katti, Sachin

    2010-01-01

    This paper discusses the design of a single channel full-duplex wireless transceiver. The design uses a combination of RF and baseband techniques to achieve full-duplexing with minimal effect on link reliability. Experiments on real nodes show the full-duplex prototype achieves median performance that is within 8% of an ideal full-duplexing system. This paper presents Antenna Cancellation, a novel technique for self-interference cancellation. In conjunction with existing RF interference cancellation and digital baseband interference cancellation, antenna cancellation achieves the amount of self-interference cancellation required for full-duplex operation. The paper also discusses potential MAC and network gains with full-duplexing. It suggests ways in which a full-duplex system can solve some important problems with existing wireless systems including hidden terminals, loss of throughput due to congestion, and large end-to-end delays. Copyright 2010 ACM.

  8. Probabilistic Medium Access Control for Full-Duplex Networks with Half-Duplex Clients

    OpenAIRE

    Chen, Shih-Ying; Huang, Ting-Feng; Lin, Kate Ching-Ju; Hong, H. -W. Peter; Sabharwal, Ashutosh

    2016-01-01

    The feasibility of practical in-band full-duplex radios has recently been demonstrated experimentally. One way to leverage full-duplex in a network setting is to enable three-node full-duplex, where a full- duplex access point (AP) transmits data to one node yet simultaneously receives data from another node. Such three-node full-duplex communication however introduces inter-client interference, directly impacting the full-duplex gain. It hence may not always be beneficial to enable three-nod...

  9. Overall performance of the duplex Stirling refrigerator

    International Nuclear Information System (INIS)

    Erbay, L. Berrin; Ozturk, M. Mete; Doğan, Bahadır

    2017-01-01

    Highlights: • Overall performance coefficient of duplex Stirling refrigerator was investigated. • A definite region for the coefficient of performance of the refrigerator in duplex Stirling is identified. • A definite region for the thermal efficiency of the heat engine in duplex Stirling is identified. • Benchmark values and design bounds of the duplex Stirling refrigerator were obtained. - Abstract: The duplex Stirling refrigerator is an integrated refrigerator consists of Stirling cycle engine and Stirling cycle refrigerator used for cooling. The equality of the work generation of the heat engine to the work consumption of the refrigerator is the primary constraint of the duplex Stirling. The duplex Stirling refrigerator is investigated thermodynamically by considering the effects of constructional and operational parameters which are namely the temperature ratios for heat engine and refrigerator, and the compression ratios for both sides. The primary concern is given to the parametric effects on the overall coefficient of performance of the duplex Stirling refrigerator. The given diagrams provide a design bounds and benchmark results that allows seeing the big picture about the cooling load and heat input relation. Moreover they ease to determine the corresponding work rate to the target cooling load. As regard to the obtained results, a definite region for coefficient of performance of the refrigerator and a definite region for the thermal efficiency of the heat engine of the duplex Stirling are identified.

  10. Duplex gall bladder: bystander or culprit.

    Science.gov (United States)

    Kumar, Jogender; Yadav, Arushi

    2017-08-30

    Gall bladder (GB) duplication is a rare anatomical malformation, which can be detected by preoperative imaging study. We present a case of duplex gall bladder in a 14-year-old boy who presented with abdominal pain. On ultrasound, he had right nephrolithiasis and duplex gall bladder. Duplex gall bladder was confirmed on MR cholangiopancreatography. There was a dilemma for surgical management of duplex gall bladder; however, he became asymptomatic after conservative treatment. Prophylactic surgery is not recommended for asymptomatic incidentally detected duplex gall bladder. Radiologists and paediatric surgeons should be sensitised about the exact anatomy of this entity. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Prolonged CT urography in duplex kidney.

    Science.gov (United States)

    Gong, Honghan; Gao, Lei; Dai, Xi-Jian; Zhou, Fuqing; Zhang, Ning; Zeng, Xianjun; Jiang, Jian; He, Laichang

    2016-05-13

    Duplex kidney is a common anomaly that is frequently associated with multiple complications. Typical computed tomography urography (CTU) includes four phases (unenhanced, arterial, parenchymal and excretory) and has been suggested to considerably aid in the duplex kidney diagnosi. Unfortunately, regarding duplex kidney with prolonged dilatation, the affected parenchyma and tortuous ureters demonstrate a lack of or delayed excretory opacification. We used prolonged-delay CTU, which consists of another prolonged-delay phase (1- to 72-h delay; mean delay: 24 h) to opacify the duplicated ureters and affected parenchyma. Seventeen patients (9 males and 8 females; age range: 2.5-56 y; mean age: 40.4 y) with duplex kidney were included in this study. Unenhanced scans did not find typical characteristics of duplex kidney, except for irregular perirenal morphology. Duplex kidney could not be confirmed on typical four-phase CTU, whereas it could be easily diagnosed in axial and CT-3D reconstruction using prolonged CTU (prolonged-delay phase). Between January 2005 and October 2010, in this review board-approved study (with waived informed consent), 17 patients (9 males and 8 females; age range: 2.5 ~ 56 y; mean age: 40.4 y) with suspicious duplex kidney underwent prolonged CTU to opacify the duplicated ureters and confirm the diagnosis. Our results suggest the validity of prolonged CTU to aid in the evaluation of the function of the affected parenchyma and in the demonstration of urinary tract malformations.

  12. Screening of Modified RNA duplexes

    DEFF Research Database (Denmark)

    Schyth, Brian Dall; Bramsen, Jesper Bertram; Kjems, Jørgen

    protection against a fish pathogenic virus. This protection corresponded with an interferon response in the fish. Here we use this fish model to screen siRNAs containing various chemical modifications of the RNA backbone for their antiviral activity, the overall aim being identification of an siRNA form......Because of sequence specific gene targeting activity siRNAs are regarded as promising active compounds in gene medicine. But one serious problem with delivering siRNAs as treatment is the now well-established non-specific activities of some RNA duplexes. Cellular reactions towards double stranded...... RNAs include the 2´-5´ oligoadenylate synthetase system, the protein kinase R, RIG-I and Toll-like receptor activated pathways all resulting in antiviral defence mechanism. We have previously shown that antiviral innate immune reactions against double stranded RNAs could be detected in vivo as partial...

  13. Full Duplex Emulation via Spatial Separation of Half Duplex Nodes in a Planar Cellular Network

    DEFF Research Database (Denmark)

    Thomsen, Henning; Kim, Dong Min; Popovski, Petar

    2016-01-01

    A Full Duplex Base Station (FD-BS) can be used to serve simultaneously two Half-Duplex (HD) Mobile Stations (MSs), one working in the uplink and one in the downlink, respectively. The same functionality can be realized by having two interconnected and spatially separated Half Duplex Base Stations...... (HD-BSs), which is a scheme termed CoMPflex (CoMP for In-Band Wireless Full Duplex). A FD-BS can be seen as a special case of CoMPflex with separation distance zero. In this paper we study the performance of CoMPflex in a two-dimensional cellular scenario using stochastic geometry and compare...

  14. Practical, real-time, full duplex wireless

    KAUST Repository

    Jain, Mayank; Choi, Jung Il; Kim, Taemin; Bharadia, Dinesh; Seth, Siddharth; Srinivasan, Kannan; Levis, Philip; Katti, Sachin; Sinha, Prasun

    2011-01-01

    This paper presents a full duplex radio design using signal inversion and adaptive cancellation. Signal inversion uses a simple design based on a balanced/unbalanced (Balun) transformer. This new design, unlike prior work, supports wideband and high power systems. In theory, this new design has no limitation on bandwidth or power. In practice, we find that the signal inversion technique alone can cancel at least 45dB across a 40MHz bandwidth. Further, combining signal inversion cancellation with cancellation in the digital domain can reduce self-interference by up to 73dB for a 10MHz OFDM signal. This paper also presents a full duplex medium access control (MAC) design and evaluates it using a testbed of 5 prototype full duplex nodes. Full duplex reduces packet losses due to hidden terminals by up to 88%. Full duplex also mitigates unfair channel allocation in AP-based networks, increasing fairness from 0.85 to 0.98 while improving downlink throughput by 110% and uplink throughput by 15%. These experimental results show that a re- design of the wireless network stack to exploit full duplex capability can result in significant improvements in network performance. © 2011 ACM.

  15. Energy balance and deformation mechanisms of duplexes

    Science.gov (United States)

    Mitra, Gautam; Boyer, Steven E.

    A duplex consists of a series of imbricate faults that are asymptotic to a roof thrust and a floor thrust. Depending on the final orientations of the imbricate faults and the final position of the branch lines, a duplex may be hinterland-dipping, foreland-dipping, or an antiformal stack. The exact geometry depends on various factors such as the initial dimensions of the individual slices (horses), their lithology, the amount of displacement (normalized to size of horse) on each fault, and the mechanics of movement along each fault. The energy required in duplex formation can be determined by calculating the total work involved in emplacing each horse: this is given by where W t=W p+W b+W g+W iWp is the work involved in initiating and propagating a fracture. Wb is the work involved in basal sliding, which may be frictional or some form of ductile flow, Wg is the work done against gravity during the emplacement of the horse, and Wi is the work involved in the internal deformation of the horse. By calculating and comparing these work terms it is possible to predict the conditions under which the different types of duplexes will form. Normally, the development of a hinterland-dipping duplex is most likely. However, if deformation conditions are favorable, displacements on individual imbricate faults may be very large compared to the size of the horses, leading to the formation of either antiformal stacks or foreland-dipping duplexes.

  16. Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

    KAUST Repository

    Alammouri, Ahmad; Elsawy, Hesham; Alouini, Mohamed-Slim

    2016-01-01

    Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half

  17. Duplex kidney: not just a drooping lily.

    Science.gov (United States)

    Doery, Ashlea J; Ang, Eileen; Ditchfield, Michael R

    2015-04-01

    Duplex kidneys are common, mostly asymptomatic and of no clinical significance. However, they can be associated with significant pathology, often with long-term morbidity. There is minimal literature on the review of the duplex kidney, its associated anomalies and complications. The purpose of this paper is to review our experience of imaging the spectrum of abnormalities associated with duplex kidneys in the paediatric population and correlate this with contemporary literature. A retrospective review of the radiology database in a tertiary paediatric centre was performed. A word search of the Radiology Information System for 'duplex' of patients under the age of 16 was undertaken and limited to studies performed between 2006 and 2013. Two hundred seventy-four patients were identified (age range 0-16, median 3 years, gender 59.9% female) who had 836 studies: ultrasound 598/836 (71.6%), nuclear medicine 180/836 (21.5%), micturating cystourethrogram 52/836 (6.2%), MRI 5/836 (duplex and no complication (151/274 = 55.1%), upper moiety obstruction, lower moiety reflux/scarring, multicystic dysplastic kidney, abnormal ureteric insertion and other pathology. Duplex kidneys are common and often not clinically significant. However, this study demonstrates almost 50% of paediatric patients investigated for duplex kidneys had complications requiring treatment. The most common complications were upper moiety obstruction associated with a ureterocele and lower moiety vesicoureteric reflux. Ultrasound was the most common modality for early detection of these complications. © 2015 The Royal Australian and New Zealand College of Radiologists.

  18. Duplex ultrasound surveillance after carotid artery endarterectomy.

    Science.gov (United States)

    Al Shakarchi, Julien; Lowry, Danielle; Nath, Jay; Khawaja, Aurangzaib Z; Inston, Nicholas; Tiwari, Alok

    2016-06-01

    After carotid endarterectomy (CEA), patients have been regularly followed up by duplex ultrasound imaging. However, the evidence for long-term follow-up is not clear, especially if the results from an early duplex scan are normal. This study assessed and systematically reviewed the evidence base for long-term surveillance after CEA and a normal early scan. Electronic databases were searched for studies assessing duplex surveillance after CEA in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome for this study was the incidence of restenosis after a normal early scan. The secondary outcome was the number of reinterventions after a normal early scan. The review included seven studies that reported 2317 procedures. Of those patients with a normal early scan, 2.8% (95% confidence interval, 0.7%-6%) developed a restenosis, and 0.4% (95% confidence interval, 0%-0.9%) underwent a reintervention for their restenosis during the follow-up period. This review confirms that routine postoperative duplex ultrasound surveillance after CEA is not necessary if the early duplex scan is normal. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  19. Buffer management in wireless full-duplex systems

    KAUST Repository

    Bouacida, Nader; Showail, Ahmad; Shihada, Basem

    2015-01-01

    , we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD

  20. On full duplex Gaussian relay channels with self-interference

    KAUST Repository

    Behboodi, Arash; Chaaban, Anas; Mathar, Rudolf; Alouini, Mohamed-Slim

    2016-01-01

    Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much

  1. Full-Duplex Relay Selection in Cognitive Underlay Networks

    KAUST Repository

    Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aissa, Sonia

    2017-01-01

    In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby

  2. Measuring secondary phases in duplex stainless steels

    Science.gov (United States)

    Calliari, I.; Brunelli, K.; Dabalà, M.; Ramous, E.

    2009-01-01

    The use of duplex stainless steels is limited by their susceptibility to the formation of dangerous intermetallic phases resulting in detrimental effects on impact toughness and corrosion resistance. This precipitation and the quantitative determinations of the phases have received considerable attention and different precipitation sequences (σ phase, χ phase, and carbides) have been suggested. This study investigates the phase transformation during continuous cooling and isothermal treatments in commercial duplex stainless steel grades and the effects on alloy properties, and compares the most common techniques of analysis.

  3. Full-duplex optical communication system

    Science.gov (United States)

    Shay, Thomas M. (Inventor); Hazzard, David A. (Inventor); Horan, Stephen (Inventor); Payne, Jason A. (Inventor)

    2004-01-01

    A method of full-duplex electromagnetic communication wherein a pair of data modulation formats are selected for the forward and return data links respectively such that the forward data electro-magnetic beam serves as a carrier for the return data. A method of encoding optical information is used wherein right-hand and left-hand circular polarizations are assigned to optical information to represent binary states. An application for an earth to low earth orbit optical communications system is presented which implements the full-duplex communication and circular polarization keying modulation format.

  4. Backbone conformation affects duplex initiation and duplex propagation in hybridisation of synthetic H-bonding oligomers.

    Science.gov (United States)

    Iadevaia, Giulia; Núñez-Villanueva, Diego; Stross, Alexander E; Hunter, Christopher A

    2018-06-06

    Synthetic oligomers equipped with complementary H-bond donor and acceptor side chains form multiply H-bonded duplexes in organic solvents. Comparison of the duplex forming properties of four families of oligomers with different backbones shows that formation of an extended duplex with three or four inter-strand H-bonds is more challenging than formation of complexes that make only two H-bonds. The stabilities of 1 : 1 complexes formed between length complementary homo-oligomers equipped with either phosphine oxide or phenol recognition modules were measured in toluene. When the backbone is very flexible (pentane-1,5-diyl thioether), the stability increases uniformly by an order of magnitude for each additional base-pair added to the duplex: the effective molarities for formation of the first intramolecular H-bond (duplex initiation) and subsequent intramolecular H-bonds (duplex propagation) are similar. This flexible system is compared with three more rigid backbones that are isomeric combinations of an aromatic ring and methylene groups. One of the rigid systems behaves in exactly the same way as the flexible backbone, but the other two do not. For these systems, the effective molarity for formation of the first intramolecular H-bond is the same as that found for the other two backbones, but additional H-bonds are not formed between the longer oligomers. The effective molarities are too low for duplex propagation in these systems, because the oligomer backbones cannot adopt conformations compatible with formation of an extended duplex.

  5. Ultra-short silicon MMI duplexer

    Science.gov (United States)

    Yi, Huaxiang; Huang, Yawen; Wang, Xingjun; Zhou, Zhiping

    2012-11-01

    The fiber-to-the-home (FTTH) systems are growing fast these days, where two different wavelengths are used for upstream and downstream traffic, typically 1310nm and 1490nm. The duplexers are the key elements to separate these wavelengths into different path in central offices (CO) and optical network unit (ONU) in passive optical network (PON). Multimode interference (MMI) has some benefits to be a duplexer including large fabrication tolerance, low-temperature dependence, and low-polarization dependence, but its size is too large to integrate in conventional case. Based on the silicon photonics platform, ultra-short silicon MMI duplexer was demonstrated to separate the 1310nm and 1490nm lights. By studying the theory of self-image phenomena in MMI, the first order images are adopted in order to keep the device short. A cascaded MMI structure was investigated to implement the wavelength splitting, where both the light of 1310nm and 1490nm was input from the same port, and the 1490nm light was coupling cross the first MMI and output at the cross-port in the device while the 1310nm light was coupling through the first and second MMI and output at the bar-port in the device. The experiment was carried on with the SOI wafer of 340nm top silicon. The cascaded MMI was investigated to fold the length of the duplexer as short as 117μm with the extinct ratio over 10dB.

  6. Duplex Design Project: Science Pilot Test.

    Science.gov (United States)

    Center for Research on Evaluation, Standards, and Student Testing, Los Angeles, CA.

    Work is reported towards the completion of a prototype duplex-design assessment instrument for grade-12 science. The student course-background questionnaire and the pretest section of the two-stage instrument that was developed were administered to all 134 12th-grade students at St. Clairsville High School (Ohio). Based on the information obtained…

  7. Duplex ultrasound for identifying renal artery stenosis

    DEFF Research Database (Denmark)

    Zachrisson, Karin; Herlitz, Hans; Lönn, Lars

    2017-01-01

    Background Renal artery duplex ultrasound (RADUS) is an established method for diagnosis of renal artery stenosis (RAS), but there is no consensus regarding optimal RADUS criteria. Purpose To define optimal cutoff values for RADUS parameters when screening for RAS using intra-arterial trans...

  8. Renal duplex Doppler ultrasound findings in diabetics

    International Nuclear Information System (INIS)

    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon

    1993-01-01

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  9. Renal duplex Doppler ultrasound findings in diabetics

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)

    1993-12-15

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  10. Thermal ageing of duplex stainless steels

    International Nuclear Information System (INIS)

    Massoud, J.P.; Van Duysen, J.C.; Zacharie, G.; Auger, P.; Danoix, F.

    1992-03-01

    The evolution of the mechanical properties of Mobearing anf Mo-free cast duplex stainless steels, induced by long term ageing in the range 300-400 deg C, has been studied in relation with the evolution of their microstructure. The unmixing of the ferritic Fe-Cr-Ni, solid solution by three-dimensional (sponge-like) spinodal decomposition and the precipitation of intermetallic G-phase particles are the main characteristics of this microstructural evolution

  11. Development of a lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Liljas, M.; Johansson, P.; Liu Hui-Ping; Olsson, C.O.A. [Avesta Research Centre, Avesta (Sweden). Outokumpu Stainless

    2008-06-15

    The classic series of duplex stainless steels shows very high corrosion resistance and can be used for very demanding applications. A new lean duplex steel, LDX 2101 {sup registered} (EN 1.4162, UNS S32101), has been developed with corrosion resistance on a par with standard austenitic grades. Application areas include: structural components, chemical industry, tanks and containers. The steel was designed to have equal amounts of ferrite and austenite in annealed condition and with an austenite that is stable against strain-induced martensite. Thanks to its high nitrogen content, the steel has a fast austenite reformation when subjected to thermal cycling, e.g. welding. Unlike conventional duplex grades, the formation of intermetallic phase is very sluggish, although precipitation of nitrides and carbides has a certain impact on material properties after exposure in the temperature range 600 to 800 C. The precipitation behaviour after different isothermal treatments is described and its influence on different product properties is shown. A good agreement was found between impact toughness and corrosion resistance for a wide range of thermal treatments. (orig.)

  12. Joint duplex mode selection, channel allocation, and power control for full-duplex cognitive femtocell networks

    Directory of Open Access Journals (Sweden)

    Mingjie Feng

    2015-02-01

    Full Text Available In this paper, we aim to maximize the sum rate of a full-duplex cognitive femtocell network (FDCFN as well as guaranteeing the quality of service (QoS of users in the form of a required signal to interference plus noise ratios (SINR. We first consider the case of a pair of channels, and develop optimum-achieving power control solutions. Then, for the case of multiple channels, we formulate joint duplex model selection, power control, and channel allocation as a mixed integer nonlinear problem (MINLP, and propose an iterative framework to solve it. The proposed iterative framework consists of a duplex mode selection scheme, a near-optimal distributed power control algorithm, and a greedy channel allocation algorithm. We prove the convergence of the proposed iterative framework as well as a lower bound for the greedy channel allocation algorithm. Numerical results show that the proposed schemes effectively improve the sum rate of FDCFNs.

  13. Characterization of thermal aging of duplex stainless steel by SQUID

    International Nuclear Information System (INIS)

    Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F.

    1995-01-01

    Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging

  14. Full-Duplex MIMO Small-Cell Networks: Performance Analysis

    OpenAIRE

    Atzeni, Italo; Kountouris, Marios

    2015-01-01

    Full-duplex small-cell relays with multiple antennas constitute a core element of the envisioned 5G network architecture. In this paper, we use stochastic geometry to analyze the performance of wireless networks with full-duplex multiple-antenna small cells, with particular emphasis on the probability of successful transmission. To achieve this goal, we additionally characterize the distribution of the self-interference power of the full-duplex nodes. The proposed framework reveals useful ins...

  15. Electron Beam Welding of Duplex Steels with using Heat Treatment

    Science.gov (United States)

    Schwarz, Ladislav; Vrtochová, Tatiana; Ulrich, Koloman

    2010-01-01

    This contribution presents characteristics, metallurgy and weldability of duplex steels with using concentrated energy source. The first part of the article describes metallurgy of duplex steels and the influence of nitrogen on their solidification. The second part focuses on weldability of duplex steels with using electron beam aimed on acceptable structure and corrosion resistance performed by multiple runs of defocused beam over the penetration weld.

  16. On the Performance of In-Band Full-Duplex Cooperative Communications

    KAUST Repository

    Khafagy, Mohammad Galal

    2016-01-01

    -duplex potentials. Full-duplex relaying (FDR), where intermediate nodes may now support source-destination communication via simultaneous listening/forwarding, represents one of two full-duplex settings currently recommended for deployment in future fifth

  17. Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

    KAUST Repository

    AlAmmouri, Ahmad

    2016-07-26

    Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half-duplex (HD) users\\' equipment (UEs) are required. In this context, 3-node topology (3NT) has been recently proposed for FD BSs to reuse the uplink (UL) and downlink (DL) channels with HD terminals within the same cell. In this paper, we present a tractable mathematical framework, based on stochastic geometry, for 3NT in cellular networks. To this end, we propose a design paradigm via pulse-shaping and partial overlap between UL and DL channels to maximize the harvested rate gains in 3NT. The results show that 3NT achieves a close performance to networks with FD BSs and FD UEs, denoted by 2-node topology (2NT) networks. A maximum of 5% rate loss is reported when 3NT is compared to 2NT with efficient self-interference cancellation (SIC). If the SIC in 2NT is not efficient, 3NT highly outperforms 2NT. Consequently, we conclude that, irrespective to the UE duplexing scheme, it is sufficient to have FD BSs to harvest FD rate gains.

  18. Structural Properties of G,T-Parallel Duplexes

    Directory of Open Access Journals (Sweden)

    Anna Aviñó

    2010-01-01

    Full Text Available The structure of G,T-parallel-stranded duplexes of DNA carrying similar amounts of adenine and guanine residues is studied by means of molecular dynamics (MD simulations and UV- and CD spectroscopies. In addition the impact of the substitution of adenine by 8-aminoadenine and guanine by 8-aminoguanine is analyzed. The presence of 8-aminoadenine and 8-aminoguanine stabilizes the parallel duplex structure. Binding of these oligonucleotides to their target polypyrimidine sequences to form the corresponding G,T-parallel triplex was not observed. Instead, when unmodified parallel-stranded duplexes were mixed with their polypyrimidine target, an interstrand Watson-Crick duplex was formed. As predicted by theoretical calculations parallel-stranded duplexes carrying 8-aminopurines did not bind to their target. The preference for the parallel-duplex over the Watson-Crick antiparallel duplex is attributed to the strong stabilization of the parallel duplex produced by the 8-aminopurines. Theoretical studies show that the isomorphism of the triads is crucial for the stability of the parallel triplex.

  19. Duplex ultrasound: Indications and findings in a newly created ...

    African Journals Online (AJOL)

    Duplex ultrasound: Indications and findings in a newly created facility at the University of Calabar Teaching Hospital, Calabar. ... It is recommended that timely referrals be made, and mobile Doppler units be acquired to save more lives and limbs in the developing world. Keywords: Calabar, deep venous thrombosis, duplex ...

  20. Criteria for the Segmentation of Vowels on Duplex Oscillograms.

    Science.gov (United States)

    Naeser, Margaret A.

    This paper develops criteria for the segmentation of vowels on duplex oscillograms. Previous vowel duration studies have primarily used sound spectrograms. The use of duplex oscillograms, rather than sound spectrograms, permits faster production (real time) at less expense (adding machine paper may be used). The speech signal can be more spread…

  1. Zoster duplex: a clinical report and etiologic analysis.

    Science.gov (United States)

    Zhang, Feng; Zhou, Jin

    2015-01-01

    Herpes zoster (HZ) duplex is a rare disease presentation. The mechanisms of varicella zoster virus (VZV) reactivation in multiple dermal regions are unknown. To present a HZ duplex case occurring in an immunocompetent woman and to analyze the possible underlying causes of HZ duplex. We present a HZ duplex case in an immunocompetent woman and analyzed the possible contributing factors in 36 HZ duplex cases. Continuously distributed variables were categorized by numbers and percentages. In our study, 24 cases (66.7%) were from Asia, 16 cases (44.4%) were in individuals ≥ 50 years of age, and 17 cases (47.2%) occurred in immunocompromised patients. Of the 36 cases, 23 involved women (63.9%) and 13 involved men. Eighteen patients suffering from HZ duplex, 13 of which were women (72.2%), did not suffer from any chronic systemic disease or have a long history of taking drugs. HZ duplex is a rare event that can occur in both immunocompetent and immunosuppressed individuals. HZ duplex might be associated with the Asia region, advanced age, immunosuppression, and being female.

  2. Thermal stability of DNA quadruplex-duplex hybrids.

    Science.gov (United States)

    Lim, Kah Wai; Khong, Zi Jian; Phan, Anh Tuân

    2014-01-14

    DNA has the capacity to adopt several distinct structural forms, such as duplex and quadruplex helices, which have been implicated in cellular processes and shown to exhibit important functional properties. Quadruplex-duplex hybrids, generated from the juxtaposition of these two structural elements, could find applications in therapeutics and nanotechnology. Here we used NMR and CD spectroscopy to investigate the thermal stability of two classes of quadruplex-duplex hybrids comprising fundamentally distinct modes of duplex and quadruplex connectivity: Construct I involves the coaxial orientation of the duplex and quadruplex helices with continual base stacking across the two components; Construct II involves the orthogonal orientation of the duplex and quadruplex helices with no base stacking between the two components. We have found that for both constructs, the stability of the quadruplex generally increases with the length of the stem-loop incorporated, with respect to quadruplexes comprising nonstructured loops of the same length, which showed a continuous drop in stability with increasing loop length. The stability of these complexes, particularly Construct I, can be substantially influenced by the base-pair steps proximal to the quadruplex-duplex junction. Bulges at the junction are largely detrimental to the adoption of the desired G-quadruplex topology for Construct I but not for Construct II. These findings should facilitate future design and prediction of quadruplex-duplex hybrids.

  3. Duplex tube steam reformer development program

    International Nuclear Information System (INIS)

    Lewe, C.K.; Nieto, J.M.; Papadopoulos, A.

    1978-09-01

    Work done in partial fulfillment of Task 7 of the Duplex Steam Reformer Development Program is described. The DSR concept acts as a double barrier between a process heat high temperature reactor plant (PNP) and a closed loop chemical heat pipe (CHP) for the long distance transport of chemical energy to a remote industrial user. The current state of the DSR design is described as well as related systems and equipment. The PNP concept presented is based upon work currently underway in the Federal Republic of Germany

  4. Duplex ultrasound evidence of fat embolism syndrome

    Directory of Open Access Journals (Sweden)

    Abdallah Naddaf, MD

    2016-12-01

    Full Text Available Fat embolism syndrome is a potentially fatal disease process most commonly associated with long-bone and pelvic fractures. Reports describing ultrasound evidence of fat emboli are restricted to echocardiography. We propose a new objective finding on venous duplex ultrasound imaging of the lower extremities as a useful diagnostic criterion by presenting the case reports of two patients with acute long-bone fractures, possibly leading to earlier orthopedic fixation and allocation of resources to those patients at higher risk of fat embolism syndrome.

  5. Full Duplex Communications in 5G Small Cells

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Gatnau, Marta; Berardinelli, Gilberto

    2017-01-01

    Full duplex communication promises system performance improvement over conventional half duplex communication by allowing simultaneous transmission and reception. However, such concurrent communication results in strong self interference and an increase in the overall network interference, and can...... only be exploited when traffic is available in both directions. The potential throughput gains of full duplex communication over conventional half duplex transmission in a small cell network with asymmetric traffic conditions is investigated in this contribution. The throughput performance gains...... are analysed using tools from stochastic geometry, and further confirmed through extensive system level simulations. Our findings explicitly quantify how the gains from full duplex communication depend on the traffic profile and the inter-cell interference coupling. The demonstrated throughput gains and delay...

  6. Corrosion behavior of 2205 duplex stainless steel.

    Science.gov (United States)

    Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

    1997-07-01

    The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

  7. Electrolytic pickling of duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ipek, N.; Holm, B.; Pettersson, R. [Swedish Institute for Metals Research, Drottning Kristinas vaeg 48, 11428 Stockholm (Sweden); Runnsjoe, G.; Karlsson, M. [Outokumpu Stainless AB, 77422 Avesta (Sweden)

    2005-08-01

    Pickling of duplex stainless steels has proved to be much more difficult than that of standard austenitic grades. Electrolytic pre-pickling is shown to be a key process towards facilitating the pickling process for material annealed both in the production-line and in laboratory experiments. The mechanism for the neutral electrolytic process on duplex 2205 and austenitic 316 steels has been examined and the oxide scale found to become thinner as a function of electrolytic pickling time. Spallation or peeling of the oxide induced by gas evolution did not play a decisive role. A maximum of about 20% of the current supplied to the oxidised steel surface goes to dissolution reactions whereas about 80% of the current was consumed in oxygen gas production. This makes the current utilisation very poor, particularly against the background of reports that in indirect electrolytic pickling only about 30% of the total current, supplied to the process, actually goes into the strip. A parametric study was therefore carried out to determine whether adjustment of process variables could improve the current utilisation. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  8. On phase equilibria in duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Wessman, S. [Swerea KIMAB AB, Stockholm (Sweden); Pettersson, R. [Outokumpu Stainless AB, Avesta Research Centre, Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Stockholm (Sweden)

    2010-05-15

    The equilibrium conditions of four duplex stainless steels; Fe-23Cr-4.5Ni-0.1N, Fe-22Cr-5.5Ni-3Mo-0.17N, Fe-25Cr-7Ni-4Mo-0.27N and Fe-25Cr-7Ni-4Mo-1W-1.5Cu-0.27N were studied in the temperature region from 700 to 1000 C. Phase compositions were determined with SEM EDS and the phase fractions using image analysis on backscattered SEM images. The results showed that below 1000 C the steels develop an inverse duplex structure with austenite and sigma phase, of which the former is the matrix phase. With decreasing temperature, the microstructure will be more and more complex and finely dispersed. The ferrite is, for the higher alloyed steels, only stable above 1000 C and at lower temperatures disappears in favour of intermetallic phases. The major intermetallic phase is sigma phase with small amounts of chi phase, the latter primarily in high Mo and W grades. Nitrides, not a focus in this investigation, were present as rounded particles and acicular precipitates at lower temperatures. The results were compared to theoretical predictions using the TCFE5 and TCFE6 databases. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha, E-mail: luizaeq@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Quimica; Paiva, Paulo Renato Perdigao [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET), Belo Horizonte, MG (Brazil); Viana, Adolfo Kalergis do Nascimento [APERAM South America, Timoteo, MG (Brazil)

    2017-01-15

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  10. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    International Nuclear Information System (INIS)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha; Viana, Adolfo Kalergis do Nascimento

    2017-01-01

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  11. Buffer management in wireless full-duplex systems

    KAUST Repository

    Bouacida, Nader

    2015-10-19

    Wireless full-duplex radios can simultaneously transmit and receive using the same frequency. In theory, this can double the throughput. In fact, there is only little work addressing aspects other than throughput gains in full-duplex systems. Over-buffering in today\\'s networks or the so-called “bufferbloat” phenomenon creates excessive end-to-end delays resulting in network performance degradation. Our analysis shows that full-duplex systems may suffer from high latency caused by bloated buffers. In this paper, we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD-MAC), an asynchronous media access control protocol designed for relay full-duplexing. We compare the performance of WQM in full-duplex environment to Drop Tail mechanism over various scenarios. Our solution reduces the end-to-end delay by two orders of magnitude while achieving similar throughput in most of the cases.

  12. Capturing a DNA duplex under near-physiological conditions

    Science.gov (United States)

    Zhang, Huijuan; Xu, Wei; Liu, Xiaogang; Stellacci, Francesco; Thong, John T. L.

    2010-10-01

    We report in situ trapping of a thiolated DNA duplex with eight base pairs into a polymer-protected gold nanogap device under near-physiological conditions. The double-stranded DNA was captured by electrophoresis and covalently attached to the nanogap electrodes through sulfur-gold bonding interaction. The immobilization of the DNA duplex was confirmed by direct electrical measurements under near-physiological conditions. The conductance of the DNA duplex was estimated to be 0.09 μS. We also demonstrate the control of DNA dehybridization by heating the device to temperatures above the melting point of the DNA.

  13. Corrosion behavior of sensitized duplex stainless steel.

    Science.gov (United States)

    Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

    1998-01-01

    The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

  14. Duplex stainless steel surface bay laser cladding

    International Nuclear Information System (INIS)

    Amigo, V.; Pineda, Y.; Segovia, F.; Vicente, A.

    2004-01-01

    Laser cladding is one of the most promising techniques to restore damaged surfaces and achieve properties similar to those of the base metal. In this work, duplex stainless steels have been cladded by a nickel alloy under different processing conditions. The influence of the beam speed and defocusing variables ha been evaluated in the microstructure both of the cladding and heat affected zone, HAZ. These results have been correlated to mechanical properties by means of microhardness measurements from cladding area to base metal through the interface. This technique has shown to be very appropriate to obtain controlled mechanical properties as they are determined by the solidification microstructure, originated by the transfer of mass and heat in the system. (Author) 21 refs

  15. Duplex quantum communication through a spin chain

    Science.gov (United States)

    Wang, Zhao-Ming; Bishop, C. Allen; Gu, Yong-Jian; Shao, Bin

    2011-08-01

    Data multiplexing within a quantum computer can allow for the simultaneous transfer of multiple streams of information over a shared medium thereby minimizing the number of channels needed for requisite data transmission. Here, we investigate a two-way quantum communication protocol using a spin chain placed in an external magnetic field. In our scheme, Alice and Bob each play the role of a sender and a receiver as two states, cos((θ1)/(2))0+sin((θ1)/(2))eiφ11 and cos((θ2)/(2))0+sin((θ2)/(2))eiφ21, are transferred through one channel simultaneously. We find that the transmission fidelity at each end of a spin chain can usually be enhanced by the presence of a second party. This is an important result for establishing the viability of duplex quantum communication through spin chain networks.

  16. Numerical Simulation of Duplex Steel Multipass Welding

    Directory of Open Access Journals (Sweden)

    Giętka T.

    2016-12-01

    Full Text Available Analyses based on FEM calculations have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. Such an approach to design enables obtaining significant savings in production preparation and post-weld deformation corrections and is also important for utility properties of welded joints obtained. As a result, it is possible to make changes to a simulated process before introducing them into real production as well as to test various variants of a given solution. Numerical simulations require the combination of problems of thermal, mechanical and metallurgical analysis. The study presented involved the SYSWELD software-based analysis of GMA welded multipass butt joints made of duplex steel sheets. The analysis of the distribution of stresses and displacements were carried out for typical welding procedure as during real welding tests.

  17. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    Directory of Open Access Journals (Sweden)

    Oladayo OLANIRAN

    2015-05-01

    Full Text Available Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr and Nickel (Ni were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM and X-ray diffraction (XRD. The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steel composites were investigated. The influence of composition variation of the reinforcements on the microstructural and corrosion behaviour in simulated mine water of the composites were investigated. In this manuscript, it was established that composition has great influence on the structure/properties relationship of the composites developed.

  18. Improper Signaling for Virtual Full-Duplex Relay Systems

    KAUST Repository

    Gaafar, Mohamed

    2017-02-14

    Virtual full-duplex (VFD) is a powerful solution to compensate the rate loss of half-duplex relaying without the need to full-duplex capable nodes. Inter-relay interference (IRI) challenges the operation of VFD relaying systems. Recently, improper signaling is employed at both relays of the VFD to mitigate the IRI by imposing the same signal characteristics for both relays. To further boost the achievable rate performance, asymmetric time sharing VFD relaying system is adopted with different improper signals at the half-duplex relays. The joint tuning of the three design parameters improves the achievable rate performance at different ranges of IRI and different relays locations. Extensive simulation results are presented and analyzed to show the achievable rate gain of the proposed system and understand the system behavior.

  19. Improper Signaling for Virtual Full-Duplex Relay Systems

    KAUST Repository

    Gaafar, Mohamed; Amin, Osama; Schaefer, Rafael F.; Alouini, Mohamed-Slim

    2017-01-01

    Virtual full-duplex (VFD) is a powerful solution to compensate the rate loss of half-duplex relaying without the need to full-duplex capable nodes. Inter-relay interference (IRI) challenges the operation of VFD relaying systems. Recently, improper signaling is employed at both relays of the VFD to mitigate the IRI by imposing the same signal characteristics for both relays. To further boost the achievable rate performance, asymmetric time sharing VFD relaying system is adopted with different improper signals at the half-duplex relays. The joint tuning of the three design parameters improves the achievable rate performance at different ranges of IRI and different relays locations. Extensive simulation results are presented and analyzed to show the achievable rate gain of the proposed system and understand the system behavior.

  20. Aortoiliac reconstructive surgery based upon the results of duplex scanning

    NARCIS (Netherlands)

    van der Zaag, E. S.; Legemate, D. A.; Nguyen, T.; Balm, R.; Jacobs, M. J.

    1998-01-01

    OBJECTIVE: To evaluate whether duplex scanning can replace angiography in patients operated for aortoiliac obstructive disease. DESIGN: Retrospective. MATERIALS AND METHODS: Between January 1995 and October 1996, 44 patients underwent vascular surgery of the aortoiliac tract. The study population

  1. The role of duplex stainless steels for downhole tubulars

    International Nuclear Information System (INIS)

    Francis, R.

    1993-01-01

    In sour conditions there is an increasing trend to turn to corrosion resistant alloys for downhole tubulars. The most commonly used CRA tubular is 13Cr, and there are thousands of feet in service. However, there are limits to the use of 13Cr, ie., the risk of sulphide stress corrosion cracking at high H 2 S levels, and the possibility of pitting or high corrosion rates in waters with high chloride contents. Where the service conditions are felt to be too severe for 13Cr alloys it has been traditional to switch to nickel base alloys such as alloys 825 and C-276 (UNS N08825 and N10276). The alloys are much more expensive than 13Cr, and in recent years the duplex stainless steels have been selected as alloys with superior corrosion and SSCC resistance compared with 13Cr, and having lower cost than nickel alloys. Originally the 22Cr duplex alloy (UNS 31803) was used, but more recently the 25Cr super duplex alloys (UNS S32760 and S32750) have become more available. The present paper reviews the data available for 13Cr and the limits of applicability. Data is also presented for laboratory tests for both the 22Cr and 25Cr super duplex alloys. There is extensive service experience with both 22Cr and 25Cr super duplex in the North Sea, covering both downhole tubulars, manifold and post wellhead equipment. Data is presented showing some of the sour condition being experienced in the North Sea by super duplex alloys. These results show that there is a substantial gap between the limits of use for 13Cr and the 25Cr super duplex stainless steel alloys. This means that in many sour environments super duplex stainless steel provides a cost effective alternative to nickel-base alloys

  2. Magnetic resonance urography in duplex kidney with ectopic ureteral insertion

    Directory of Open Access Journals (Sweden)

    Conjeevaram Rajendrarao Thambidorai

    2011-01-01

    Full Text Available This is a report on the use of magnetic resonance urography (MRU in a 6-year-old girl who presented with urinary incontinence. She had a left duplex kidney with poorly functioning upper moiety and ectopic insertion of the dilated upper pole ureter. MRU has been shown to be superior to conventional imaging techniques in delineating poorly functioning moieties of duplex kidneys and ectopic ureters.

  3. Transcranial Duplex Sonography Predicts Outcome following an Intracerebral Hemorrhage.

    Science.gov (United States)

    Camps-Renom, P; Méndez, J; Granell, E; Casoni, F; Prats-Sánchez, L; Martínez-Domeño, A; Guisado-Alonso, D; Martí-Fàbregas, J; Delgado-Mederos, R

    2017-08-01

    Several radiologic features such as hematoma volume are related to poor outcome following an intracerebral hemorrhage and can be measured with transcranial duplex sonography. We sought to determine the prognostic value of transcranial duplex sonography in patients with intracerebral hemorrhage. We conducted a prospective study of patients diagnosed with spontaneous intracerebral hemorrhage. Transcranial duplex sonography examinations were performed within 2 hours of baseline CT, and we recorded the following variables: hematoma volume, midline shift, third ventricle and lateral ventricle diameters, and the pulsatility index in both MCAs. We correlated these data with the CT scans and assessed the prognostic value of the transcranial duplex sonography measurements. We assessed early neurologic deterioration during hospitalization and mortality at 1-month follow-up. We included 35 patients with a mean age of 72.2 ± 12.8 years. Median baseline hematoma volume was 9.85 mL (interquartile range, 2.74-68.29 mL). We found good agreement and excellent correlation between transcranial duplex sonography and CT when measuring hematoma volume ( r = 0.791; P duplex sonography measurements showed that hematoma volume was an independent predictor of early neurologic deterioration (OR, 1.078; 95% CI, 1.023-1.135) and mortality (OR, 1.089; 95% CI, 1.020-1.160). A second regression analysis with CT variables also demonstrated that hematoma volume was associated with early neurologic deterioration and mortality. When we compared the rating operation curves of both models, their predictive power was similar. Transcranial duplex sonography showed an excellent correlation with CT in assessing hematoma volume and midline shift in patients with intracerebral hemorrhage. Hematoma volume measured with transcranial duplex sonography was an independent predictor of poor outcome. © 2017 by American Journal of Neuroradiology.

  4. On the Secrecy Degrees of Freedom with Full-Duplex Communication

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Mogensen, Preben Elgaard

    2017-01-01

    of such an application. The potential of full duplex nodes in improving the physical layer security of a communication link is investigated in this contribution. We specifically derive the information theoretic secrecy degrees of freedom measure for a pair of nodes communicating in full duplex mode. Moreover, closed...... and the delay reduction of full duplex communication are somewhat limited in realistic network settings, leading researchers to study other possible applications of full duplex communication which can provide significantly higher gains over half duplex communication. Physical layer security is an example...... form expressions for the instantaneous and ergodic throughput gain of full duplex communication over conventional half duplex is derived. The secrecy degrees of freedom with full duplex is shown to be two as opposed to that of zero in half duplex mode....

  5. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    OpenAIRE

    Prabhu Paulraj; Rajnish Garg

    2015-01-01

    Duplex Stainless Steels (DSS) and Super Duplex Stainless Steel (SDSS) have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic pha...

  6. Phase Transformations in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon-Jun [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as σ and χ can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (σ + χ) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, σ was stabilized with increasing Cr addition and χ by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by

  7. Clinical utility of carotid duplex ultrasound prior to cardiac surgery.

    Science.gov (United States)

    Lin, Judith C; Kabbani, Loay S; Peterson, Edward L; Masabni, Khalil; Morgan, Jeffrey A; Brooks, Sara; Wertella, Kathleen P; Paone, Gaetano

    2016-03-01

    Clinical utility and cost-effectiveness of carotid duplex examination prior to cardiac surgery have been questioned by the multidisciplinary committee creating the 2012 Appropriate Use Criteria for Peripheral Vascular Laboratory Testing. We report the clinical outcomes and postoperative neurologic symptoms in patients who underwent carotid duplex ultrasound prior to open heart surgery at a tertiary institution. Using the combined databases from our clinical vascular laboratory and the Society of Thoracic Surgery, a retrospective analysis of all patients who underwent carotid duplex ultrasound within 13 months prior to open heart surgery from March 2005 to March 2013 was performed. The outcomes between those who underwent carotid duplex scanning (group A) and those who did not (group B) were compared. Among 3233 patients in the cohort who underwent cardiac surgery, 515 (15.9%) patients underwent a carotid duplex ultrasound preoperatively, and 2718 patients did not (84.1%). Among the patients who underwent carotid screening vs no screening, there was no statistically significant difference in the risk factors of cerebrovascular disease (10.9% vs 12.7%; P = .26), prior stroke (8.2% vs 7.2%; P = .41), and prior transient ischemic attack (2.9% vs 3.3%; P = .24). For those undergoing isolated coronary artery bypass grafting (CABG), 306 (17.8%) of 1723 patients underwent preoperative carotid duplex ultrasound. Among patients who had carotid screening prior to CABG, the incidence of carotid disease was low: 249 (81.4%) had minimal or mild stenosis (duplex scanning and those who did not. Primary outcomes of patients who underwent open heart surgery also showed no difference in the perioperative mortality (5.1% vs 6.9%; P = .14) and stroke (2.6% vs 2.4%; P = .85) between patients undergoing preoperative duplex scanning and those who did not. Operative intervention of severe carotid stenosis prior to isolated CABG occurred in 2 of the 17 patients (11.8%) identified who

  8. Corrosion behaviour of sintered duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Utrilla, M. Victoria; Urena, Alejandro; Otero, Enrique; Munez, Claudio Jose [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, C/ Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2004-07-01

    Duplex austenite-ferrite stainless steels were prepared by mixing austenitic (316L) and ferritic (434L) atomized powders. Although different 316L/434L ratios were prepared, present work centred its study on 50% ferrite - 50% austenite sintered steel. The powders were mixed and pressed at 700 MPa and sintered at 1250 deg. C for 30 min in vacuum. The cooling rate was 5 deg. C/min. Solution treatment was carried out to homogenize the microstructure at 1100 deg. C during 20 min. A microstructural study of the material in solution was performed, evaluating the microstructure, proportion and shape of porosity, and ferrite percentage. This last was measured by two methods, quantitative metallography and Fischer ferrito-metry. The materials were heat treated in the range of 700 to 1000 deg. C, for 10, 30 and 60 min and water quenched, to study the microstructural changes and the influence on the intergranular corrosion resistance. The method used to evaluate the sensitization to the intergranular corrosion was the electrochemical potentio-kinetic reactivation procedure (EPR). The test solution was 0.5 M H{sub 2}SO{sub 4} + 0,01 M KSCN at 30 deg. C. The criterion used to evaluate the sensitization was the ratio between the maximum reactivation density (Ir) and the maximum activation density (Ia). The results of the electrochemical tests were discussed in relation with the microstructures observed at the different heat treatments. (authors)

  9. THE INFLUENCE OF POSTHEAT TREATMENT ON FERRITE REDISTRIBUTION IN DUPLEX STEELS ELECTRON BEAM WELDS

    OpenAIRE

    Zita Iždinská; František Kolenič

    2009-01-01

    The duplex stainless steel is two-phase steel with the structure composed of austenite and ferrite with optimum austenite/ferrite proportion 50%. At present, classical arc processes for welding duplex steels are generally regarded as acceptable. On the other hand electron and laser beam welding is up to now considered less suitable for welding duplex steels. The submitted work presents the results of testing various thermal conditions at welding duplex stainless steel with electron beam. It w...

  10. Analysing Self Interference Cancellation in Full Duplex Radios

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Shafique Ansari, Imran; Berardinelli, Gilberto

    2016-01-01

    Full duplex communication promises a theoretical $100\\%$ throughput gain by doubling the number of simultaneous transmissions. Such compelling gains are conditioned on perfect cancellation of the self interference power resulting from simultaneous transmission and reception. Generally, self...... interference power is modelled as a noise-like constant level interference floor. However, experimental validations have shown that the self interference power is in practice a random variable depending on a number of factors such as the surrounding wireless environment and the degree of interference...... cancellation. In this study, we derive an analytical model for the residual self interference power, and demonstrate various applications of the derived model in analysing the performance of a Full Duplex radio. In general, full duplex communication is found to provide only modest throughput gains over half...

  11. CMOS serial link for fully duplexed data communication

    Science.gov (United States)

    Lee, Kyeongho; Kim, Sungjoon; Ahn, Gijung; Jeong, Deog-Kyoon

    1995-04-01

    This paper describes a CMOS serial link allowing fully duplexed 500 Mbaud serial data communication. The CMOS serial link is a robust and low-cost solution to high data rate requirements. A central charge pump PLL for generating multiphase clocks for oversampling is shared by several serial link channels. Fully duplexed serial data communication is realized in the bidirectional bridge by separating incoming data from the mixed signal on the cable end. The digital PLL accomplishes process-independent data recovery by using a low-ratio oversampling, a majority voting, and a parallel data recovery scheme. Mostly, digital approach could extend its bandwidth further with scaled CMOS technology. A single channel serial link and a charge pump PLL are integrated in a test chip using 1.2 micron CMOS process technology. The test chip confirms upto 500 Mbaud unidirectional mode operation and 320 Mbaud fully duplexed mode operation with pseudo random data patterns.

  12. Features of residual stresses in duplex stainless steel butt welds

    Science.gov (United States)

    Um, Tae-Hwan; Lee, Chin-Hyung; Chang, Kyong-Ho; Nguyen Van Do, Vuong

    2018-04-01

    Duplex stainless steel finds increasing use as an alternative to austenitic stainless steel, particularly where chloride or sulphide stress corrosion cracking is of primary concern, due to the excellent combination of strength and corrosion resistance. During welding, duplex stainless steel does not create the same magnitude or distribution of weld-induced residual stresses as those in welded austenitic stainless steel due to the different physical and mechanical properties between them. In this work, an experimental study on the residual stresses in butt-welded duplex stainless steel is performed utilizing the layering technique to investigate the characteristics of residual stresses in the weldment. Three-dimensional thermos-mechanical-metallurgical finite element analysis is also performed to confirm the residual stress measurements.

  13. Comparison of simulated and measured quantities of a duplex reactor

    Energy Technology Data Exchange (ETDEWEB)

    Koskela, M.; Kajava, M. [ABB Marine, Helsinki (Finland)

    1997-12-31

    The purpose of this article is to illustrate the use of an analog simulator as a design tool when designing new power electric equipment. The purpose of simulation is to predict the functionality of electrical equipment to be constructed. Duplex reactor is an electromagnetic device designed to reduce voltage harmonics and short circuit currents in the ship electrical network. In this report a comparison between simulated and measured electrical quantities of a duplex reactor has been made. The purpose of the measurements was to show the correct functioning of the reactor. The simulation results and the measured waveforms corresponds well to each other. (orig.) 4 refs.

  14. Mechanical properties of welded joints of duplex steels

    International Nuclear Information System (INIS)

    Kawiak, M.; Nowacki, J.

    2003-01-01

    The paper presents the study results of mechanical properties of duplex steels UNS S31803 welded joints as well as duplex and NV A36 steels welded joints. They have ben welded by FCAW method in CO 2 using FCW 2205-H flux-cored wire. The joints have been subjected: tensile tests, impact tests, bending tests, hardness tests and metallographic investigations. The influence of welding parameters and mechanical properties of the joints was appreciated. The welding method assured high tensile strength of the joints (approximately 770 MPa) and high impact strength of the welds (approximately 770 J). All samples were broken outside of welds. (author)

  15. Duplex sonography of the near-surface leg veins

    International Nuclear Information System (INIS)

    Mendoza, E.

    2007-01-01

    The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins

  16. Reducing duplex examinations in patients with iatrogenic pseudoaneurysms.

    Science.gov (United States)

    Stone, Patrick A; Aburahma, Ali F; Flaherty, Sarah K

    2006-06-01

    Ultrasound-guided thrombin injection has become the initial treatment of choice for femoral access-related pseudoaneurysms. Patients typically undergo serial duplex examinations to assess for spontaneous resolution of small iatrogenic pseudoaneurysms (IPSAs) (IPSAs (>2.5 cm). We evaluated the impact of a revised treatment algorithm that includes primary treatment of both small (2.5 cm), rather than observation of smaller ones, and attempts to establish a single duplex examination via a point-of-care treatment strategy. We reviewed 105 consecutive patients treated with ultrasound-guided thrombin injection from July 2001 through September 2004. Patient, IPSAs, characteristics, and treatment methods were examined. The number of duplex examinations per patient was evaluated over the treatment interval. Also, published cost data were used to compare primary treatment of small ISPAs vs observation with serial duplex examinations. Successful thrombosis occurred in 103 (98.1%) of 105 treated pseudoaneurysms. No minor or major complications occurred after thrombin injection in either small or large ISPAs, and both failures requiring operation were in the large aneurysm group. The recurrence rate for the series was 1.9% (2/105), and both recurrences were successfully treated with an additional thrombin injection. A single injection was successful in treating 43 (97.7%) of 44 small (IPSAs, and one required a second injection. Patients had an average of 3.3 duplex examinations in our first year of treatment experience, which declined to 1.5 by our third year with the institution of a point-of-care service model for all pseudoaneurysms. Based on this decreased use of duplex examination and an average treatment cohort of 35 IPSA patients per year our institution, we determined this results in a reduction of 35 hours of laboratory time and nearly 70 ultrasounds per year. Similarly for small pseudoaneurysms, a point-of-service primary treatment program rather than observation

  17. Optimisation of welding procedures for duplex and superduplex stainless steels

    International Nuclear Information System (INIS)

    Westin, Elin M.

    2014-01-01

    Austenitic stainless steels are increasingly being replaced by duplex grades that can offer similar corrosion resistance with far higher strength. This increased strength makes it possible to reduce material consumption whilst also decreasing transport and construction costs. Although established welding methods used for austenitic steels can be used for duplex steels, modification of the procedures can lead to improved results. This paper reviews the welding of duplex stainless steel and examines precautions that may be required. The advantages and disadvantages of different welding methods are highlighted and some high productivity solutions are presented. The application of a more efficient process with a high deposition rate (e.g. flux- cored arc welding) can decrease labour costs. Further close control of heat input and interpass temperature can result in more favourable microstructures and final properties. Although welding adversely affects the corrosion resistance of austenitic and duplex stainless steels, particularly the pitting resistance, relative to the parent material, this problem can be minimised by proper backing gas protection and subsequent pickling.

  18. A most spectrum-efficient duplexing system: CDD

    Science.gov (United States)

    Lee, William C. Y.

    2001-10-01

    The game to play in wireless communications when it comes to increasing spectrum efficiency is to eliminate interference. Currently, all cellular systems use FDD (Frequency Division Duplexing) in an attempt to eliminate the interference from the adjacent cells. Through the use of many technologies only one type of interference remains and that is the adjacent base-tohome mobile interference. TDD (Time Division Duplexing) has not been used for mobile cellular systems, not only because of the adjacent base-to-home mobile interference, but also because of the additional adjacent base-to-home base interference, and adjacent mobile-to-home mobile interference. Therefore, TDD can only be used for small, confined area systems. CDD (Code Division Duplexing) can eliminate all three kinds of interference; the adjacent base-to-home mobile, the adjacent baseto-home base, and the adjacent mobile- to- home in cellular systems. Eliminating each of these interferences makes CDD the most spectrum efficient duplexing system. This talk will elaborate on a set of smart codes, which will make an efficient CDD system a reality.

  19. Increased Y-chromosome detection by SRY duplexing

    DEFF Research Database (Denmark)

    Hansen, Morten Høgh; Clausen, Frederik Banch; Dziegiel, Morten Hanefeld

    2012-01-01

    Determining fetal sex noninvasively is dependent of a robust assay. We designed a novel SRY assay and combined it with a SRY assay from literature forming a duplex assay with the same fluorescent dye to increase detection of Y-chromosome at low cell-free fetal DNA or chimeric DNA concentrations....

  20. Full-Duplex Relay Selection in Cognitive Underlay Networks

    KAUST Repository

    Khafagy, Mohammad Galal

    2017-09-30

    In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint, which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic FDRS with residual self-interference (RSI) by deriving the exact cumulative distribution function of its end-to-end signal-to-interference-plus-noise ratio under Nakagami-m fading. We also evaluate the offered diversity gain of relay selection for different full-duplex cooperation schemes in the presence/absence of a direct source-destination link. When the adopted RSI link gain model is sublinear in the relay power, which agrees with recent research findings, we show that remarkable diversity gain can be recovered even in the presence of an interfering direct link. Second, we evaluate the end-to-end performance of FDRS with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

  1. ON SECURE FULL DUPLEX COMMUNICATION IN MOBILE AD HOC NETWORK

    OpenAIRE

    S. C. Dutta; Sudha Singh; D. K. Singh

    2013-01-01

    This paper is to establish Ad Hoc network in mobile phones and start fully secured full duplex communication in any situation. This type of communication will be cost effective and it will be fastest way of communication in case of any server failure or server error.

  2. Micromechanics of base pair unzipping in the DNA duplex

    International Nuclear Information System (INIS)

    Volkov, Sergey N; Paramonova, Ekaterina V; Yakubovich, Alexander V; Solov’yov, Andrey V

    2012-01-01

    All-atom molecular dynamics (MD) simulations of DNA duplex unzipping in a water environment were performed. The investigated DNA double helix consists of a Drew-Dickerson dodecamer sequence and a hairpin (AAG) attached to the end of the double-helix chain. The considered system is used to examine the process of DNA strand separation under the action of an external force. This process occurs in vivo and now is being intensively investigated in experiments with single molecules. The DNA dodecamer duplex is consequently unzipped pair by pair by means of the steered MD. The unzipping trajectories turn out to be similar for the duplex parts with G⋅C content and rather distinct for the parts with A⋅T content. It is shown that during the unzipping each pair experiences two types of motion: relatively quick rotation together with all the duplex and slower motion in the frame of the unzipping fork. In the course of opening, the complementary pair passes through several distinct states: (i) the closed state in the double helix, (ii) the metastable preopened state in the unzipping fork and (iii) the unbound state. The performed simulations show that water molecules participate in the stabilization of the metastable states of the preopened base pairs in the DNA unzipping fork. (paper)

  3. Reliability Capacity of Half-Duplex Channels with Strict Deadlines

    DEFF Research Database (Denmark)

    Costa, Rui; Roetter, Daniel Enrique Lucani; Vinhoza, Tiago

    2015-01-01

    A fundamental characterization of a half-duplex wireless system with packet losses under traffic with hard deadlines is instrumental to understanding and developing efficient, coding aware policies for real-time applications. We set forth the concept of reliability capacity with a limited number ...

  4. Corrosion behavior of duplex and reference cladding in NPP Grohnde

    International Nuclear Information System (INIS)

    Besch, O.A.; Yagnik, S.K.; Eucken, C.M.; Bradley, E.R.

    1996-01-01

    The Nuclear Fuel Industry Research (NFIR) Group undertook a lead test assembly (LTA) program in NPP Grohnde PWR in Germany to assess the corrosion performance of duplex and reference cladding. Two identical 16 by 16 LTAs, each containing 32 peripheral test rods, completed four reactor cycles, reaching a peak rod burnup of 46 MWd/kgU. The results from poolside examinations performed at the end of each cycle, together with power histories and coolant chemistry, are reported. Five different cladding materials were characterized during fabrication. The corrosion performance of the cladding materials was tracked in long-term tests in high-pressure, high-temperature autoclaves. The relative ranking of corrosion behavior in such tests corresponded well with the in-reactor corrosion performance. The extent and distribution of hydriding in duplex and reference specimens during the autoclave testing has been characterized. The in-reactor corrosion data indicate that the low-tin Zircaloy-4 reference cladding, R2, had an improved corrosion resistance compared to high-tin Zircaloy-4 reference cladding, R1. Two types of duplex cladding, D1 (Zr-2.5% Nb) and D2 (Zr-0.4% Fe-0.5% Sn), showed an even further improvement in corrosion resistance compared to R2 cladding. The third duplex cladding, D3 (Zr-4 + 1.0% Nb), had significantly less corrosion resistance, which was inferior to R1. The in-reactor and out-reactor corrosion performances have been ranked

  5. Comprehensive Educational Assessment for the States: The Duplex Design.

    Science.gov (United States)

    Bock, R. Darrell; Mislevy, Robert

    State testing programs often attempt to provide annual information for use in student guidance and qualification, school and program evaluation, and broad policy decisions. With the development of a new type of assessment instrument, the "duplex design," the several functions of state testing programs can be served in a single test…

  6. Podiatry Ankle Duplex Scan: Readily Learned and Accurate in Diabetes.

    Science.gov (United States)

    Normahani, Pasha; Powezka, Katarzyna; Aslam, Mohammed; Standfield, Nigel J; Jaffer, Usman

    2018-03-01

    We aimed to train podiatrists to perform a focused duplex ultrasound scan (DUS) of the tibial vessels at the ankle in diabetic patients; podiatry ankle (PodAnk) duplex scan. Thirteen podiatrists underwent an intensive 3-hour long simulation training session. Participants were then assessed performing bilateral PodAnk duplex scans of 3 diabetic patients with peripheral arterial disease. Participants were assessed using the duplex ultrasound objective structured assessment of technical skills (DUOSATS) tool and an "Imaging Score". A total of 156 vessel assessments were performed. All patients had abnormal waveforms with a loss of triphasic flow. Loss of triphasic flow was accurately detected in 145 (92.9%) vessels; the correct waveform was identified in 139 (89.1%) cases. Participants achieved excellent DUOSATS scores (median 24 [interquartile range: 23-25], max attainable score of 26) as well as "Imaging Scores" (8 [8-8], max attainable score of 8) indicating proficiency in technical skills. The mean time taken for each bilateral ankle assessment was 20.4 minutes (standard deviation ±6.7). We have demonstrated that a focused DUS for the purpose of vascular assessment of the diabetic foot is readily learned using intensive simulation training.

  7. Full-duplex wireless communications systems self-interference cancellation

    CERN Document Server

    Le-Ngoc, Tho

    2017-01-01

    This book introduces the development of self-interference (SI)-cancellation techniques for full-duplex wireless communication systems. The authors rely on estimation theory and signal processing to develop SI-cancellation algorithms by generating an estimate of the received SI and subtracting it from the received signal. The authors also cover two new SI-cancellation methods using the new concept of active signal injection (ASI) for full-duplex MIMO-OFDM systems. The ASI approach adds an appropriate cancelling signal to each transmitted signal such that the combined signals from transmit antennas attenuate the SI at the receive antennas. The authors illustrate that the SI-pre-cancelling signal does not affect the data-bearing signal. This book is for researchers and professionals working in wireless communications and engineers willing to understand the challenges of deploying full-duplex and practical solutions to implement a full-duplex system. Advanced-level students in electrical engineering and computer ...

  8. Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

    Directory of Open Access Journals (Sweden)

    ENCENG SULAEMAN

    2013-07-01

    The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 dB. Isolation between Tx port and Rx port about 15 dB. Keywords: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, and Long Term Evolution.

  9. An evaluation of nuclear design characteristics of duplex burnable poison rods for extended cycle core

    International Nuclear Information System (INIS)

    Lee, D. J.; Kim, M. H.; Song, K. W.

    2003-01-01

    Nuclear design characteristics of duplex burnable poison rod were evaluated for three integral type burnable absorbers; Gadolinia, Erbia and IFBA. Inter-comparison was done for both 12 and 24 month cycle for Korean Standard Nuclear Plant. Fuel assemblies with duplex BP was designed to the equivalent assembly with 8 and 16 gadolinia BP 2 . Duplex BP is composed of inner region of natural U-Gd 2 O 3 , and outer shell of, UO 2 -Er2O 3 . In order to evaluate the duplex BP, assemblies with erbia and IFBA were compared with alternative options. A sensitivity studies were performed to the size of region, compositions and location of duplex BPs. It was shown that duplex BP gave favorable k-infinite curve to burnup, but IFBA provided the least residual reactivity penalty as EOC. Erbia was good for more negative MTCs. IFBA and erbia had better neutronic performance than gadolinia od duplex BP in the aspect of pin power peaking

  10. Renal pelvis urothelial carcinoma of the upper moiety in complete right renal duplex: a case report.

    Science.gov (United States)

    Zhang, Yiran; Yu, Quanfeng; Zhang, Zhihong; Liu, Ranlu; Xu, Yong

    2015-01-01

    Urothelial carcinoma (UC) originated from renal pelvis is the common tumor of the urinary system, however, neoplasia of the renal pelvis in duplex kidneys is extremely rare, especially in the complete renal and ureteral duplex cases. We present the first case of renal pelvis UC of the upper moiety in a complete right renal duplex. This male patient has bilateral complete renal and ureteral duplex. To the best of our knowledge, this is the first reported case of renal pelvis UC in a complete renal duplex system. After this experience we feel that the diagnosis of renal pelvis UC in duplex kidneys is not so easy, and once the diagnosis is determined, the whole renal duplex units and bladder cuff or ectopic orifice should be excised radically.

  11. Full-Duplex Communications in Large-Scale Cellular Networks

    KAUST Repository

    AlAmmouri, Ahmad

    2016-04-01

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink interference. This thesis presents a tractable framework, based on stochastic geometry, to study FD communications in multi-tier cellular networks. Particularly, we assess the FD communications effect on the network performance and quantify the associated gains. The study proves the vulnerability of the uplink to the downlink interference and shows that the improved FD rate gains harvested in the downlink (up to 97%) comes at the expense of a significant degradation in the uplink rate (up to 94%). Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between the uplink and the downlink frequency bands. We derive the required conditions to harvest rate gains from the α-duplex scheme and show its superiority to both the FD and half-duplex (HD) schemes. In particular, we show that the α-duplex scheme provides a simultaneous improvement of 28% for the downlink rate and 56% for the uplink rate. We also show that the amount of the overlap can be optimized based on the network design objective. Moreover, backward compatibility is an essential ingredient for the success of new technologies. In the context of in-band FD communication, FD base stations (BSs) should support HD users\\' equipment (UEs) without sacrificing the foreseen FD gains. The results show that FD-UEs are not necessarily required to harvest rate gains from FD-BSs. In particular, the results show that adding FD-UEs to FD-BSs offers a maximum of 5% rate gain over FD-BSs and HD-UEs case, which is a marginal gain compared to the burden required to implement FD transceivers at the UEs\\' side. To this end, we shed light on practical scenarios where HD-UEs operation with FD-BSs outperforms the

  12. Duplex Ultrasonography Has Limited Utility in Detection of Postoperative DVT After Primary Total Joint Arthroplasty.

    Science.gov (United States)

    Vira, Shaleen; Ramme, Austin J; Alaia, Michael J; Steiger, David; Vigdorchik, Jonathan M; Jaffe, Frederick

    2016-07-01

    Duplex ultrasound is routinely used to evaluate suspected deep venous thrombosis after total joint arthroplasty. When there is a clinical suspicion for a pulmonary embolism, a chest angiogram (chest CTA) is concomitantly obtained. Two questions were addressed: First, for the population of patients who receive duplex ultrasound after total joint arthroplasty, what is the rate of positive results? Second, for these patients, how many of these also undergo chest CTA for clinical suspicion of pulmonary embolus and how many of these tests are positive? Furthermore, what is the correlation between duplex ultrasound results and chest CTA results? A retrospective chart review was conducted of total joint replacement patients in 2011 at a single institution. Inclusion criteria were adult patients who underwent a postoperative duplex ultrasonography for clinical suspicion of deep venous thrombosis (DVT). Demographic data, result of duplex scan, clinical indications for obtaining the duplex scan, and DVT prophylaxis used were recorded. Additionally, if a chest CTA was obtained for clinical suspicion for pulmonary embolus, results and clinical indication for obtaining the test were recorded. The rate of positive results for duplex ultrasonography and chest CTA was computed and correlated based on clinical indications. Two hundred ninety-five patients underwent duplex ultrasonography of which only 0.7% were positive for a DVT. One hundred three patients underwent a chest CTA for clinical suspicion of a pulmonary embolism (PE) of which 26 revealed a pulmonary embolus, none of which had a positive duplex ultrasound. Postoperative duplex scans have a low rate of positive results. A substantial number of patients with negative duplex results subsequently underwent chest CTA for clinical suspicion for which a pulmonary embolus was found, presumably resulting from a DVT despite negative duplex ultrasound result. A negative duplex ultrasonography should not rule out the presence of a

  13. Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

    KAUST Repository

    Soury, Hamza; Elsawy, Hesham; Alouini, Mohamed-Slim

    2017-01-01

    This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have

  14. Tensile properties of duplex UNS S32205 and lean duplex UNS S32304 steels and the influence of short duration 475 ºC aging

    Directory of Open Access Journals (Sweden)

    Sérgio Souto Maior Tavares

    2012-12-01

    Full Text Available Duplex stainless steels are high strength and corrosion resistant steels extensively used in the petrochemical and chemical industries. The aging at 475 ºC for long periods of time provokes embrittlement and deterioration of corrosion resistance. However, short duration aging at 475 ºC may be used as heat treatment to improve mechanical resistance with small decrease in the other properties. In this work the flow stress curves of lean duplex UNS S32304 and duplex UNS S32205 steels were modeled with Hollomon's equation and work hardening exponents (n were determined. The analyses were conducted in specimens annealed and heat treated at 475 ºC for short periods of time. The aging at 475 ºC for 4 hours, 8 hours and 12 hours promoted significant hardening with small decrease of ductility. The work hardening exponents of both steels were compared, being higher in the duplex steel than in the lean duplex grade.

  15. Mechanical Deformation Behavior of Lean Duplex 329LA Steel

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Byung-Jun [Research Institute of Industrial Science and Technology, Pohang (Korea, Republic of); Choi, Jeom-Yong [POSCO Technical Research Lab., Pohang (Korea, Republic of); Park, Kyung-Tae [Hanvat National University, Daejeon (Korea, Republic of); Lee, Ho Seong [Kyungpook National University, Daegu (Korea, Republic of)

    2015-09-15

    The tensile response of Lean Duplex 329LA stainless steel was investigated over various strain rates. It was observed that the mechanical response, including in particular the total elongation of the tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s-1 to 10-4 s-1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by dislocation glide, resulting in deterioration of the elongation. The substructure of the ferritic phase showed a dislocation cell structure, independent of the applied strain rate. The optimum mechanical properties of lean duplex stainless steel thus can be obtained by controlling the deformation mode in the austenitic phase.

  16. Mechanical Deformation Behavior of Lean Duplex 329LA Steel

    International Nuclear Information System (INIS)

    Yoon, Byung-Jun; Choi, Jeom-Yong; Park, Kyung-Tae; Lee, Ho Seong

    2015-01-01

    The tensile response of Lean Duplex 329LA stainless steel was investigated over various strain rates. It was observed that the mechanical response, including in particular the total elongation of the tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s-1 to 10-4 s-1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by dislocation glide, resulting in deterioration of the elongation. The substructure of the ferritic phase showed a dislocation cell structure, independent of the applied strain rate. The optimum mechanical properties of lean duplex stainless steel thus can be obtained by controlling the deformation mode in the austenitic phase.

  17. Duplex-tube sodium-indication steam generator

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1984-01-01

    The steam generator with duplex tubes and sodium indication is connected to the main sodium input and output via the inlet and outlet chambers and has indication spaces connected to the interspaces of the duplex tubes. The first indication space is linked with the auxiliary inlet pipe to the inlet chamber and the second indication space is connected with the auxiliary pipe to the outlet chamber. Mounted to the auxiliary inlet pipe is at least one closure, i.e., a valve or electromagnetic stop. Mounted on the auxiliary outlet pipe is an indication sensor, e.g., a sodium flow sensor. At least one indication space is provided with an alarm sensor, e.g., a thermocouple, a pressure gauge and one sensor to monitor the hydrogen content of sodium. (J.P.)

  18. Comments on process of duplex coatings on aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Samir H.A.; QIAN Han-cheng(钱翰城); XIA Bo-cai(夏伯才); WU Shi-ming(吴仕明)

    2004-01-01

    Despite the great achievements made in improvement of wear resistance properties of aluminum alloys,their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on aluminum alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

  19. Weld oxide formation on lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Westin, E.M. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden)], E-mail: elin.westin@outokumpu.com; Olsson, C.-O.A. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Brinellvaegen 23, SE-100 44 Stockholm (Sweden)

    2008-09-15

    Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition.

  20. Listen and talk full-duplex cognitive radio networks

    CERN Document Server

    Liao, Yun; Han, Zhu

    2016-01-01

    This brief focuses on the use of full-duplex radio in cognitive radio networks, presenting a novel spectrum sharing protocol that allows the secondary users to simultaneously sense and access the vacant spectrum. This protocol, called “Listen-and-talk” (LAT), is evaluated by both mathematical analysis and computer simulations in comparison with other existing protocols, including the listen-before-talk protocol. In addition to LAT-based signal processing and resource allocation, the brief discusses techniques such as spectrum sensing and dynamic spectrum access. The brief proposes LAT as a suitable access scheme for cognitive radio networks, which can support the quality-of-service requirements of these high priority applications. Fundamental theories and key techniques of cognitive radio networks are also covered. Listen and Talk: Full-duplex Cognitive Radio Networks is designed for researchers, developers, and professionals involved in cognitive radio networks. Advanced-level students studying signal pr...

  1. Standard test methods for characterizing duplex grain sizes

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 These test methods provide simple guidelines for deciding whether a duplex grain size exists. The test methods separate duplex grain sizes into one of two distinct classes, then into specific types within those classes, and provide systems for grain size characterization of each type. 1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult appropriate safety and health practices and determine the applicability of regulatory limitations prior to its use.

  2. Weld oxide formation on lean duplex stainless steel

    International Nuclear Information System (INIS)

    Westin, E.M.; Olsson, C.-O.A.; Hertzman, S.

    2008-01-01

    Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition

  3. Implementation of real-time duplex synthetic aperture ultrasonography

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Larsen, Lee; Kjeldsen, Thomas

    2015-01-01

    This paper presents a real-time duplex synthetic aperture imaging system, implemented on a commercially available tablet. This includes real-time wireless reception of ultrasound signals and GPU processing for B-mode and Color Flow Imaging (CFM). The objective of the work is to investigate the im...... and that the required bandwidth between the probe and processing unit is within the current Wi-Fi standards....

  4. Internal stresses in an austeno-ferritic duplex stainless steel

    International Nuclear Information System (INIS)

    Verhaeghe, B.; Brechet, Y.; Louchet, F.; Massoud, J.P.; Touzeau, D.

    1996-04-01

    Austeno-ferritic duplex steels possess microstructures containing comparable volume fractions of hard and soft phases which are bi-percolated. They are therefore liable to develop large internal stresses during straining. The evolution and the relaxation of these stresses and the occurrence of damage are characterized using Bauschinger tests. Thermally aged and non-aged material behaviour are compared. Plastic flow in the hard phase is shown to be significantly efficient in releasing these internal stresses. (authors). 15 refs., 8 figs

  5. Investigation of hot cracking resistance of 2205 duplex steel

    Energy Technology Data Exchange (ETDEWEB)

    Adamiec, J; Scibisz, B, E-mail: janusz.adamiec@polsl.pl [Silesian University of Technology, Faculty of Materials Science and Metallurgy, ul. Krasinskiego 8, PL-40019 Katowice (Poland)

    2010-02-15

    Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the R{sub f}parameter (R{sub f} = (T{sub liquidus} - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 deg. C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of T{sub L} = 1465 deg. C and a solidus temperature of T{sub S} = 1454 deg. C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 deg. C. As the value of the NDT temperature 1367 deg. C was applied while for DRT the assumed temperature was 1375 deg. C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

  6. Investigation of hot cracking resistance of 2205 duplex steel

    Science.gov (United States)

    Adamiec, J.; Ścibisz, B.

    2010-02-01

    Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the Rfparameter (Rf = (Tliquidus - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 °C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of TL = 1465 °C and a solidus temperature of TS = 1454 °C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 °C. As the value of the NDT temperature 1367 °C was applied while for DRT the assumed temperature was 1375 °C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

  7. Investigation of hot cracking resistance of 2205 duplex steel

    International Nuclear Information System (INIS)

    Adamiec, J; Scibisz, B

    2010-01-01

    Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the R f parameter (R f = (T liquidus - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 deg. C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of T L = 1465 deg. C and a solidus temperature of T S = 1454 deg. C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 deg. C. As the value of the NDT temperature 1367 deg. C was applied while for DRT the assumed temperature was 1375 deg. C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

  8. On full duplex Gaussian relay channels with self-interference

    KAUST Repository

    Behboodi, Arash

    2016-08-15

    Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much is known about its effect on the fundamental limits of relaying systems. In this work, we consider the full duplex three-node relay channel with SI where SI is modeled as an additive Gaussian noise whose variance is dependent on instantaneous input power. The classical achievable rates and upper bounds for the single three-node relay channel no longer apply due to the structure of SI. Achievable rates for Decode-and-Forward (DF) and Compress-and-Forward (CF) and upper bounds on the capacity are derived assuming Gaussian inputs and SI. The deterministic model is also introduced and its capacity is characterized. The optimal joint source-relay distributions is discussed. Numerical results are provided comparing the achievable rates and upper bound. © 2016 IEEE.

  9. Duplex Schemes in Multiple Antenna Two-Hop Relaying

    Directory of Open Access Journals (Sweden)

    Anja Klein

    2008-04-01

    Full Text Available A novel scheme for two-hop relaying defined as space division duplex (SDD relaying is proposed. In SDD relaying, multiple antenna beamforming techniques are applied at the intermediate relay station (RS in order to separate downlink and uplink signals of a bi-directional two-hop communication between two nodes, namely, S1 and S2. For conventional amplify-and-forward two-hop relaying, there appears a loss in spectral efficiency due to the fact that the RS cannot receive and transmit simultaneously on the same channel resource. In SDD relaying, this loss in spectral efficiency is circumvented by giving up the strict separation of downlink and uplink signals by either time division duplex or frequency division duplex. Two novel concepts for the derivation of the linear beamforming filters at the RS are proposed; they can be designed either by a three-step or a one-step concept. In SDD relaying, receive signals at S1 are interfered by transmit signals of S1, and receive signals at S2 are interfered by transmit signals of S2. An efficient method in order to combat this kind of interference is proposed in this paper. Furthermore, it is shown how the overall spectral efficiency of SDD relaying can be improved if the channels from S1 and S2 to the RS have different qualities.

  10. Duplex geometry: an example from the Moine Thrust Belt

    Science.gov (United States)

    Bowler, S.

    1987-04-01

    The geometry and microstructure of a small duplex formed in one bed from the Moine Thrust Belt of northwest Scotland is reported. The structure is seen in oblique section, within the Cambrian Pipe-rock, in an area of low strain. A range of movement direction indicators are present in the structure. An early grain shape fabric developed close to the roof thrust is taken as the best estimate of the overall movement direction towards 287°. Slickensides in the gouge developed on movement planes within the duplex show varied orientations on a given plane, and are not considered useful indicators of thrust transport direction. Branch lines exposed converge and diverge, suggesting little lateral continuity of the exposed structure. The microstructures present within the structure indicate an increase in localised deformation, and in cataclastic behavior as the duplex evolved. Early layer parallel shear is ubiquitous, giving rise to an elongate grain shape fabric close to bedding surfaces. In early formed horses, a layer-parallel, oblate grain shape fabric, which shows localised slip zones, is overprinted by gouge formation. Later formed horses show only fracturing and gouge development. This sequence is attributed to stick-slip behavior in the propagation or displacement of the original fault, now the floor thrust.

  11. Microstructures and mechanical properties of duplex low carbon steel

    Science.gov (United States)

    Alfirano; Eben, U. S.; Hidayat, M.

    2018-04-01

    The microstructures behavior of duplex cold-rolled low carbon steel for automotive applications has been investigated. Intercritical annealing treatment is commonly used to develop a duplex low carbon steel containing ferrite and martensite. To get a duplex phase ferrite and martensite, the specimens were heated at inter-critical annealing temperature of 775°C - 825°C, for heating time up to 20 minutes, followed by water-quenched. The hardness of specimens was studied. The optical microscopy was used to analyze the microstructures. The optimal annealing conditions (martensite volume fraction approaching 20%) at 775°C with a heating time of 10 minutes was achieved. The highest hardness value was obtained in cold-rolled specimens of 41% in size reduction for intercritical annealing temperature of 825°C. In this condition, the hardness value was 373 HVN. The correlation between intercritical annealing temperature and time can be expressed in the transformation kinetics as fγ/fe = 1-exp(-Ktn) wherein K and n are grain growth rate constant and Avrami’s exponent, respectively. From experiment, the value of K = 0.15 and n = 0.461. Using the relationship between temperatures and heating time, activation energy (Q) can be calculated that is 267 kJ/mol.

  12. Development and test evaluation of duplex steam reformer tube

    International Nuclear Information System (INIS)

    Allen, D.C.; Meyer, D.J.; Pflasterer, G.R.

    1980-01-01

    For HTR applications involving a steam reformer (SR), it is uncertain whether an intermediate heat exchanger (IHX) is required. There are several system configurations that could be developed for the application of nuclear heat using the steam reformer reaction. The considerations (advantages vs. disadvantages) for each of the system configurations are summarized. The approach that technically and economically appears to be the most attractive, in studies conducted by General Electric, combines the SR process heat exchanger and the IHX in a single component using a duplex tube. A central question concerning the duplex tube concept is whether the design would provide adequate leak monitoring capability and significant reduction in tritium and hydrogen diffusion, while introducing only a small increase in overall temperature difference from the helium to the process gas. A cooperative GE-KFA effort was undertaken to develop, fabricate, test, and evaluate a duplex steam reformer tube. GE was responsible for the development and fabrication of the tube, and KFA was responsible for testing the tube in the EVA I facility at Juelich. Both GE and KFA are evaluating the thermochemical and metallurgical test data. Actual fabrication of the tube was performed by Foster-Wheeler in accordance with the GE design. This paper reviews the highlights of the fabrication development and preliminary evaluation of the test data

  13. Qualitative comparison of duplex Stirling and absorption refrigerators in domestic applications

    Energy Technology Data Exchange (ETDEWEB)

    Shao, H. [Global Cooling BV, Zutphen (Netherlands)

    2000-07-01

    A qualitative comparison has been carried out between the duplex Stirling and the absorption refrigerator for domestic applications. The duplex Stirling has many advantages over the absorption refrigerator on efficiency, modulation, suitability, operating costs, pollution reduction. Based on the state of the art of free-piston gas-bearing and linear-motor Stirling engines and coolers, it appears technically and economically feasible to develop the duplex Stirling to compete with the absorption refrigerator for heat-driven domestic refrigeration. (orig.)

  14. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    OpenAIRE

    Yurtisik,Koray; Tirkes,Suha; Dykhno,Igor; Gur,C. Hakan; Gurbuz,Riza

    2013-01-01

    Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

  15. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  16. Characterization of microstructure and texture across dissimilar super duplex/austenitic stainless steel weldment joint by super duplex filler metal

    Energy Technology Data Exchange (ETDEWEB)

    Eghlimi, Abbas, E-mail: a.eghlimi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, Morteza [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandarian, Masoomeh [Department of Materials Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Zabolian, Azam [Department of Natural Resources, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Szpunar, Jerzy A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon SK S7N 5A9 (Canada)

    2015-08-15

    In the present paper, microstructural changes across an as-welded dissimilar austenitic/duplex stainless steel couple welded by a super duplex stainless steel filler metal using gas tungsten arc welding process is characterized with optical microscopy and electron back-scattered diffraction techniques. Accordingly, variations of microstructure, texture, and grain boundary character distribution of base metals, heat affected zones, and weld metal were investigated. The results showed that the weld metal, which was composed of Widmanstätten austenite side-plates and allotriomorphic grain boundary austenite morphologies, had the weakest texture and was dominated by low angle boundaries. The welding process increased the ferrite content but decreased the texture intensity at the heat affected zone of the super duplex stainless steel base metal. In addition, through partial ferritization, it changed the morphology of elongated grains of the rolled microstructure to twinned partially transformed austenite plateaus scattered between ferrite textured colonies. However, the texture of the austenitic stainless steel heat affected zone was strengthened via encouraging recrystallization and formation of annealing twins. At both interfaces, an increase in the special character coincident site lattice boundaries of the primary phase as well as a strong texture with <100> orientation, mainly of Goss component, was observed. - Graphical abstract: Display Omitted - Highlights: • Weld metal showed local orientation at microscale but random texture at macroscale. • Intensification of <100> orientated grains was observed adjacent to the fusion lines. • The austenite texture was weaker than that of the ferrite in all duplex regions. • Welding caused twinned partially transformed austenites to form at SDSS HAZ. • At both interfaces, the ratio of special CSL boundaries of the primary phase increased.

  17. THE INFLUENCE OF POSTHEAT TREATMENT ON FERRITE REDISTRIBUTION IN DUPLEX STEELS ELECTRON BEAM WELDS

    Directory of Open Access Journals (Sweden)

    Zita Iždinská

    2009-04-01

    Full Text Available The duplex stainless steel is two-phase steel with the structure composed of austenite and ferrite with optimum austenite/ferrite proportion 50%. At present, classical arc processes for welding duplex steels are generally regarded as acceptable. On the other hand electron and laser beam welding is up to now considered less suitable for welding duplex steels. The submitted work presents the results of testing various thermal conditions at welding duplex stainless steel with electron beam. It was shown, that application of suitable postheat made possible to reduce the ferrite content in weld metal.

  18. Residual stresses and fatigue in a duplex stainless steel

    International Nuclear Information System (INIS)

    Johansson, Johan

    1999-01-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  19. Residual stresses and fatigue in a duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Johan

    1999-05-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  20. The value and economic analysis of routine postoperative carotid duplex ultrasound surveillance after carotid endarterectomy.

    Science.gov (United States)

    AbuRahma, Ali F; Srivastava, Mohit; AbuRahma, Zachary; Jackson, Will; Mousa, Albeir; Stone, Patrick A; Dean, L Scott; Green, Jason

    2015-08-01

    Several studies have reported on the role of postoperative duplex ultrasound surveillance after carotid endarterectomy (CEA) with varying results. Most of these studies had a small sample size or did not analyze cost-effectiveness. We analyzed 489 of 501 CEA patients with patch closure. All patients had immediate postoperative duplex ultrasound examination and were routinely followed up both clinically and with duplex ultrasound at regular intervals of 1 month, 6 months, 12 months, and every 12 months thereafter. A Kaplan-Meier analysis was used to estimate the rate of ≥50% and ≥80% post-CEA restenosis over time and the time frame of progression from normal to ≥50% or ≥80% restenosis. The cost of post-CEA duplex surveillance was also estimated. Overall, 489 patients with a mean age of 68.5 years were analyzed. Ten of these had residual postoperative ≥50% stenosis, and 37 did not undergo a second duplex ultrasound examination and therefore were not included in the final analysis. The mean follow-up was 20.4 months (range, 1-63 months), with a mean number of duplex ultrasound examinations of 3.6 (range, 1-7). Eleven of 397 patients (2.8%) with a normal finding on immediate postoperative duplex ultrasound vs 4 of 45 (8.9%) with mild stenosis on immediate postoperative duplex ultrasound progressed to ≥50% restenosis (P = .055). Overall, 15 patients (3.1%) had ≥50% restenosis, 9 with 50% to duplex ultrasound), which equals $1,408,320, to detect only four patients with ≥80% to 99% restenosis who may have been potential candidates for reintervention. This study shows that the value of routine postoperative duplex ultrasound surveillance after CEA with patch closure may be limited, particularly if the finding on immediate postoperative duplex ultrasound is normal or shows minimal disease. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  1. Force-Induced Rupture of a DNA Duplex: From Fundamentals to Force Sensors.

    Science.gov (United States)

    Mosayebi, Majid; Louis, Ard A; Doye, Jonathan P K; Ouldridge, Thomas E

    2015-12-22

    The rupture of double-stranded DNA under stress is a key process in biophysics and nanotechnology. In this article, we consider the shear-induced rupture of short DNA duplexes, a system that has been given new importance by recently designed force sensors and nanotechnological devices. We argue that rupture must be understood as an activated process, where the duplex state is metastable and the strands will separate in a finite time that depends on the duplex length and the force applied. Thus, the critical shearing force required to rupture a duplex depends strongly on the time scale of observation. We use simple models of DNA to show that this approach naturally captures the observed dependence of the force required to rupture a duplex within a given time on duplex length. In particular, this critical force is zero for the shortest duplexes, before rising sharply and then plateauing in the long length limit. The prevailing approach, based on identifying when the presence of each additional base pair within the duplex is thermodynamically unfavorable rather than allowing for metastability, does not predict a time-scale-dependent critical force and does not naturally incorporate a critical force of zero for the shortest duplexes. We demonstrate that our findings have important consequences for the behavior of a new force-sensing nanodevice, which operates in a mixed mode that interpolates between shearing and unzipping. At a fixed time scale and duplex length, the critical force exhibits a sigmoidal dependence on the fraction of the duplex that is subject to shearing.

  2. An unusual mode of DNA duplex association: Watson-Crick interaction of all-purine deoxyribonucleic acids.

    Science.gov (United States)

    Battersby, Thomas R; Albalos, Maria; Friesenhahn, Michel J

    2007-05-01

    Nucleic acid duplexes associating through purine-purine base pairing have been constructed and characterized in a remarkable demonstration of nucleic acids with mixed sequence and a natural backbone in an alternative duplex structure. The antiparallel deoxyribose all-purine duplexes associate specifically through Watson-Crick pairing, violating the nucleobase size-complementarity pairing convention found in Nature. Sequence-specific recognition displayed by these structures makes the duplexes suitable, in principle, for information storage and replication fundamental to molecular evolution in all living organisms. All-purine duplexes can be formed through association of purines found in natural ribonucleosides. Key to the formation of these duplexes is the N(3)-H tautomer of isoguanine, preferred in the duplex, but not in aqueous solution. The duplexes have relevance to evolution of the modern genetic code and can be used for molecular recognition of natural nucleic acids.

  3. Numerical modeling and optimization of machining duplex stainless steels

    Directory of Open Access Journals (Sweden)

    Rastee D. Koyee

    2015-01-01

    Full Text Available The shortcomings of the machining analytical and empirical models in combination with the industry demands have to be fulfilled. A three-dimensional finite element modeling (FEM introduces an attractive alternative to bridge the gap between pure empirical and fundamental scientific quantities, and fulfill the industry needs. However, the challenging aspects which hinder the successful adoption of FEM in the machining sector of manufacturing industry have to be solved first. One of the greatest challenges is the identification of the correct set of machining simulation input parameters. This study presents a new methodology to inversely calculate the input parameters when simulating the machining of standard duplex EN 1.4462 and super duplex EN 1.4410 stainless steels. JMatPro software is first used to model elastic–viscoplastic and physical work material behavior. In order to effectively obtain an optimum set of inversely identified friction coefficients, thermal contact conductance, Cockcroft–Latham critical damage value, percentage reduction in flow stress, and Taylor–Quinney coefficient, Taguchi-VIKOR coupled with Firefly Algorithm Neural Network System is applied. The optimization procedure effectively minimizes the overall differences between the experimentally measured performances such as cutting forces, tool nose temperature and chip thickness, and the numerically obtained ones at any specified cutting condition. The optimum set of input parameter is verified and used for the next step of 3D-FEM application. In the next stage of the study, design of experiments, numerical simulations, and fuzzy rule modeling approaches are employed to optimize types of chip breaker, insert shapes, process conditions, cutting parameters, and tool orientation angles based on many important performances. Through this study, not only a new methodology in defining the optimal set of controllable parameters for turning simulations is introduced, but also

  4. Identification of sigma and chi phases in duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Llorca-Isern, Núria, E-mail: nullorca@ub.edu [Departament de Ciència dels Materials i Enginyeria Metallurgica, Facultat de Química, Universitat de Barcelona, Marti-Franqués 1, 08028 Barcelona (Spain); López-Luque, Héctor, E-mail: hlopezlu7@alumnes.ub.edu [Departament de Ciència dels Materials i Enginyeria Metallurgica, Facultat de Química, Universitat de Barcelona, Marti-Franqués 1, 08028 Barcelona (Spain); López-Jiménez, Isabel, E-mail: ilopezji9@alumnes.ub.edu [Departament de Ciència dels Materials i Enginyeria Metallurgica, Facultat de Química, Universitat de Barcelona, Marti-Franqués 1, 08028 Barcelona (Spain); Biezma, Maria Victoria, E-mail: maria.biezma@unican.es [Department of Earth, Materials Science and Engineering, University of Cantabria - UC, Gamazo, 1, 39004 Santander (Spain)

    2016-02-15

    The aim of this work is to find out the most suitable method for detecting and analyzing accurately the formation conditions of secondary phases, particularly Sigma-phase (σ-phase) and Chi-phase (χ-phase) in duplex stainless steels (UNS S32205 and UNS S32750). The microstructure was characterized after a solution annealing at 1080 °C followed by an isothermal heating at 830 °C for different time ranges, ranging from 1 min to 9 h, in order to enlighten the controversial point concerning the mechanism of χ-phase nucleation in relation with the σ-phase. Etched samples were observed using optical microscopy (MO), and scanning electron microscopy (FESEM) with a backscattered electron detector (BSE) was used on unetched samples. Compositional microanalysis (EDS) was carried out for identifying the different phases present in the steels. Sigma phase was easily observed using different etching procedures, whereas χ-phase was only clearly detected with FESEM–BSE on unetched samples. The compositional analyses showed that the molybdenum content in χ-phase almost doubles the content of this element in σ-phase, and as a result the kinetics of nucleation and growth were also found to be remarkably faster when the alloy content in the steel is higher. In addition, chromium nitrides and carbides were also observed to precipitate as a result of the heat treatments and, in the case of the chromium nitrides, they act as a favorable site for the nucleation of σ-phase and χ-phase. - Highlights: • Microscopy was used on heat treated duplex steels for microstructure identification. • FESEM–BSE observation on unetched samples provided the best contrast between phases. • Analyses of carbides, nitrides, chi and sigma phases were possible by EDS and WDS. • Chromium nitrides act as favorable site for the nucleation of chi and sigma phases. • Secondary phases nucleation kinetics are faster in superduplex than in duplex steels.

  5. Surveillance Duplex Ultrasonography of Stent Grafts for Popliteal Aneurysms.

    Science.gov (United States)

    Pineda, Danielle M; Troutman, Douglas A; Dougherty, Matthew J; Calligaro, Keith D

    2016-05-01

    Stent grafts, also known as covered stents, have become an increasingly acceptable treatment for popliteal artery aneurysms. However, endovascular exclusion confers lower primary patency compared to traditional open bypass and exclusion. The purpose of this study was to evaluate whether duplex ultrasonography (DU) can reliably diagnose failing stent grafts placed for popliteal artery aneurysms prior to occlusion. Between June 5, 2007, and March 11, 2014, 21 stent grafts (Viabahn; Gore, Flagstaff, Arizona) were placed in 19 patients for popliteal artery aneurysms. All patients had at least 1 follow-up duplex scan postoperatively. Mean follow-up was 28.9 months (9-93 months). Postoperative DU surveillance was performed in our Intersocietal Accreditation Commission noninvasive vascular laboratory at 1 week postprocedure and every 6 months thereafter. Duplex ultrasonography measured peak systolic velocities (PSVs) and ratio of adjacent PSVs (Vr) every 5 cm within the stent graft and adjacent arteries. We retrospectively classified the following factors as "abnormal DU findings": focal PSV > 300 cm/s, uniform PSVs 3.0. These DU criteria were derived from laboratory-specific data that we previously published on failing stent grafts placed for lower extremity occlusive disease. Four of the 21 stent grafts presented with symptomatic graft thrombosis within 6 months of a normal DU. Three of these 4 patients presented with rest pain and underwent thrombectomy (2) or vein bypass (1), and 1 elected for nonintervention for claudication. Our results suggest that surveillance DU using criteria established for grafts placed for occlusive disease may not be useful for predicting stent graft failure in popliteal artery aneurysms. © The Author(s) 2016.

  6. Toughness and other mechanical properties of the duplex stainless steel 2205

    International Nuclear Information System (INIS)

    Sieurin, H.; Sandstroem, R.

    2003-01-01

    The use and range of potential applications of duplex stainless steel continuously increase. An overview of the mechanical properties of duplex stainless steel 2205 is presented with focus on toughness properties. Impact and fracture toughness as well as strength results from the European research project, EcoPress, are presented. (orig.)

  7. Interference alignment for degrees of freedom improvement in 3-relay half-duplex systems

    KAUST Repository

    Park, Seongho; Ko, Youngchai; Park, Kihong; Alouini, Mohamed-Slim

    2011-01-01

    In a half-duplex relaying, the capacity pre-log factor is a major drawback in spectral efficiency. This paper proposes a linear precoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help

  8. Importance of diastolic velocities in the detection of celiac and mesenteric artery disease by duplex ultrasound

    DEFF Research Database (Denmark)

    Perko, M J; Just, S; Schroeder, T V

    1997-01-01

    To assess the predictive value of ultrasound duplex scanning in the detection of superior mesenteric artery (SMA) and celiac artery (CA) occlusive disease.......To assess the predictive value of ultrasound duplex scanning in the detection of superior mesenteric artery (SMA) and celiac artery (CA) occlusive disease....

  9. Four-Tap RF Canceller Evaluation for Indoor In-Band Full-Duplex Wireless Operation

    Science.gov (United States)

    2016-07-24

    I. INTRODUCTION In-band full-duplex (IBFD) wireless operation can help alleviate the frequency spectrum congestion issues faced by current system...Valkama, “Wideband self-adaptive rf cancellation circuit for full- duplex radio: Operating principle and measurements,” in 2015 IEEE 81st Vehicular

  10. A Dual-Specific Targeting Approach Based on the Simultaneous Recognition of Duplex and Quadruplex Motifs.

    Science.gov (United States)

    Nguyen, Thi Quynh Ngoc; Lim, Kah Wai; Phan, Anh Tuân

    2017-09-20

    Small-molecule ligands targeting nucleic acids have been explored as potential therapeutic agents. Duplex groove-binding ligands have been shown to recognize DNA in a sequence-specific manner. On the other hand, quadruplex-binding ligands exhibit high selectivity between quadruplex and duplex, but show limited discrimination between different quadruplex structures. Here we propose a dual-specific approach through the simultaneous application of duplex- and quadruplex-binders. We demonstrated that a quadruplex-specific ligand and a duplex-specific ligand can simultaneously interact at two separate binding sites of a quadruplex-duplex hybrid harbouring both quadruplex and duplex structural elements. Such a dual-specific targeting strategy would combine the sequence specificity of duplex-binders and the strong binding affinity of quadruplex-binders, potentially allowing the specific targeting of unique quadruplex structures. Future research can be directed towards the development of conjugated compounds targeting specific genomic quadruplex-duplex sites, for which the linker would be highly context-dependent in terms of length and flexibility, as well as the attachment points onto both ligands.

  11. Value of Duplex scanning in the selection of patients for percutaneous transluminal angioplasty

    NARCIS (Netherlands)

    van der Heijden, F. H.; Legemate, D. A.; van Leeuwen, M. S.; Mali, W. P.; Eikelboom, B. C.

    1993-01-01

    Duplex scanning is becoming increasingly important in the diagnosis and follow-up of arterial lesions, though most surgeons and radiologists currently still prefer diagnostic angiography prior to percutaneous transluminal angioplasty (PTA). We performed PTA based on Duplex scanning alone in 31

  12. Can duplex Doppler ultrasound replace computerized tomography in staging patients with renal cell carcinoma?

    NARCIS (Netherlands)

    Bos, SD; Mensink, HJA

    The purpose of this study was to evaluate the accuracy and reliability of duplex Doppler ultrasound (US) and computerized tomography (CT) in staging patients with renal cell carcinoma (RCC). Sixty-six patients were evaluated pre-operatively with duplex Doppler ultrasound and CT. The results were

  13. Distance-dependent duplex DNA destabilization proximal to G-quadruplex/i-motif sequences

    Science.gov (United States)

    König, Sebastian L. B.; Huppert, Julian L.; Sigel, Roland K. O.; Evans, Amanda C.

    2013-01-01

    G-quadruplexes and i-motifs are complementary examples of non-canonical nucleic acid substructure conformations. G-quadruplex thermodynamic stability has been extensively studied for a variety of base sequences, but the degree of duplex destabilization that adjacent quadruplex structure formation can cause has yet to be fully addressed. Stable in vivo formation of these alternative nucleic acid structures is likely to be highly dependent on whether sufficient spacing exists between neighbouring duplex- and quadruplex-/i-motif-forming regions to accommodate quadruplexes or i-motifs without disrupting duplex stability. Prediction of putative G-quadruplex-forming regions is likely to be assisted by further understanding of what distance (number of base pairs) is required for duplexes to remain stable as quadruplexes or i-motifs form. Using oligonucleotide constructs derived from precedented G-quadruplexes and i-motif-forming bcl-2 P1 promoter region, initial biophysical stability studies indicate that the formation of G-quadruplex and i-motif conformations do destabilize proximal duplex regions. The undermining effect that quadruplex formation can have on duplex stability is mitigated with increased distance from the duplex region: a spacing of five base pairs or more is sufficient to maintain duplex stability proximal to predicted quadruplex/i-motif-forming regions. PMID:23771141

  14. Optimization of welding variables for duplex stainless steel by GTAW and SMAW

    International Nuclear Information System (INIS)

    Ajmal, M.; Anwar, M.Y.; Nawaz, A.

    2006-01-01

    The main problems faced during the welding of duplex stainless steels are cleanliness and slag inclusions. In the present work the methods to eliminate these problems were studied during the welding of duplex stainless steel by Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW). Since the duplex stainless steel is an expensive material, the initial experiments for optimization of welding variables were. carried out on low carbon steel (CS) plates with duplex consumables. Welding of butt groove joints on CS plates was carried with various sets of welding variables i.e. current, voltage and arc energy using duplex consumables. The. radiographic inspection, micro-structural observations and hardness testing of the welds suggested the welding variables that will produce a sound weld on CS plate. These optimized variables were then used for the welding of edge groove joint and T -joint on duplex stainless steel by GTAW and SMAW processes. The hardness and micro-structural study of the joints produced on duplex stainless steel by GTAW and SMAW with duplex consumables were also studied. No slag inclusions and porosity were observed in the microstructure of these weldments and their properties were found similar to the parent metal. (author)

  15. Full-duplex MIMO system based on antenna cancellation technique

    DEFF Research Database (Denmark)

    Foroozanfard, Ehsan; Franek, Ondrej; Tatomirescu, Alexandru

    2014-01-01

    The performance of an antenna cancellation technique for a multiple-input– multiple-output (MIMO) full-duplex system that is based on null-steering beamforming and antenna polarization diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual......-polarized patch antennas operating at 2.4 GHz is described. The measurement results show an average of 60 dB self-interference cancellation over 200 MHz bandwidth. Moreover, a decoupling level of up to 22 dB is achieved for MIMO multiplexing using antenna polarization diversity. The performance evaluation...

  16. Design of a Microwave Duplexer without Ferrite and without Magnet

    Directory of Open Access Journals (Sweden)

    F. Mejri

    2018-06-01

    Full Text Available In this paper we present the design, realization and characterization of a microwave duplexer, compact, easy to realize and integrate into systems such as ground penetrating radars. It is made without the use of ferrite or magnet. This device is designed in the S band and made in micro-ribbon technology. It consists of a power divider and two RF amplifiers, low gain, using a BFR91 bipolar transistor. The latter is frequently available and inexpensive. Measurements made on a vector network analyzer have shown a low insertion loss with insulation considered satisfactory – for low power applications - between the transmitter (Tx and the receiver (Rx circuits.

  17. Physical-Layer Security of a Buffer-Aided Full-Duplex Relaying System

    KAUST Repository

    El Shafie, Ahmed

    2016-07-07

    This letter proposes a novel hybrid half-/full-duplex relaying scheme to enhance the relay channel security. A source node (Alice) communicates with her destination node (Bob) in the presence of a buffer-aided full-duplex relay node (Rooney) and a potential eavesdropper (Eve). Rooney adopts two different relaying, namely randomize-and-forward and decode-andforward relaying strategies, to improve the security of the legitimate system. In the first relaying strategy, Rooney uses a codebook different from that used at Alice. In the second relaying strategy, Rooney and Alice use the same codebooks. In addition, Rooney switches between half-duplex and full-duplex modes to further enhance the security of the legitimate system. The numerical results demonstrate that our proposed scheme achieves a significant average secrecy end-to-end throughput improvement relative to the conventional bufferless full-duplex relaying scheme.

  18. Analyzing the Potential of Full Duplex in 5G Ultra-Dense Small Cell Networks

    DEFF Research Database (Denmark)

    Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

    2016-01-01

    Full duplex technology has become an attractive solution for future 5th Generation (5G) systems for accommodating the exponentially growing mobile traffic demand. Full duplex allows a node to transmit and receive simultaneously in the same frequency band, thus, theoretically, doubling the system...... throughput over conventional half duplex systems. A key limitation in building a feasible full duplex node is the self-interference, i.e., the interference generated by the transmitted signal to the desired signal received on the same node. This constraint has been overcome given the recent advances...... in the self-interference cancellation technology. However, there are other limitations in achieving the theoretical full duplex gain: residual self-interference, traffic constraints and inter-cell and intra-cell interference. The contribution of this article is twofold. Firstly, achievable levels of self...

  19. On the Potential of Full Duplex Performance in 5G Ultra-Dense Small Cell Networks

    DEFF Research Database (Denmark)

    Gatnau, Marta; Fleischer, Marko; Berardinelli, Gilberto

    2016-01-01

    inter-cell interference and traffic constraints. In this paper, we first study the self-interference cancellation capabilities by using a real demonstrator. Results show that achieving ~110 dB of cancellation is already possible with the current available technology, thus providing the required level...... of isolation to build an operational full duplex node. Secondly, we investigate the inter-cell interference and traffic constraints impact on the full duplex performance in 5th generation systems. System level results show that both the traffic and the inter-cell interference can significantly reduce...... the potential gain of full duplex with respect to half duplex. However, for large traffic asymmetry, full duplex can boost the performance of the lightly loaded link....

  20. Evaluation of Microstructure and Mechanical Properties in Dissimilar Austenitic/Super Duplex Stainless Steel Joint

    Science.gov (United States)

    Rahmani, Mehdi; Eghlimi, Abbas; Shamanian, Morteza

    2014-10-01

    To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmanstätten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.

  1. Physical-Layer Security of a Buffer-Aided Full-Duplex Relaying System

    KAUST Repository

    El Shafie, Ahmed; Salem, Ahmed Sultan; Al-Dhahir, Naofal

    2016-01-01

    This letter proposes a novel hybrid half-/full-duplex relaying scheme to enhance the relay channel security. A source node (Alice) communicates with her destination node (Bob) in the presence of a buffer-aided full-duplex relay node (Rooney) and a potential eavesdropper (Eve). Rooney adopts two different relaying, namely randomize-and-forward and decode-andforward relaying strategies, to improve the security of the legitimate system. In the first relaying strategy, Rooney uses a codebook different from that used at Alice. In the second relaying strategy, Rooney and Alice use the same codebooks. In addition, Rooney switches between half-duplex and full-duplex modes to further enhance the security of the legitimate system. The numerical results demonstrate that our proposed scheme achieves a significant average secrecy end-to-end throughput improvement relative to the conventional bufferless full-duplex relaying scheme.

  2. Water-evaporation reduction by duplex films: application to the human tear film.

    Science.gov (United States)

    Cerretani, Colin F; Ho, Nghia H; Radke, C J

    2013-09-01

    Water-evaporation reduction by duplex-oil films is especially important to understand the physiology of the human tear film. Secreted lipids, called meibum, form a duplex film that coats the aqueous tear film and purportedly reduces tear evaporation. Lipid-layer deficiency is correlated with the occurrence of dry-eye disease; however, in-vitro experiments fail to show water-evaporation reduction by tear-lipid duplex films. We review the available literature on water-evaporation reduction by duplex-oil films and outline the theoretical underpinnings of spreading and evaporation kinetics that govern behavior of these systems. A dissolution-diffusion model unifies the data reported in the literature and identifies dewetting of duplex films into lenses as a key challenge to obtaining significant evaporation reduction. We develop an improved apparatus for measuring evaporation reduction by duplex-oil films including simultaneous assessment of film coverage, stability, and temperature, all under controlled external mass transfer. New data reported in this study fit into the larger body of work conducted on water-evaporation reduction by duplex-oil films. Duplex-oil films of oxidized mineral oil/mucin (MOx/BSM), human meibum (HM), and bovine meibum (BM) reduce water evaporation by a dissolution-diffusion mechanism, as confirmed by agreement between measurement and theory. The water permeability of oxidized-mineral-oil duplex films agrees with those reported in the literature, after correction for the presence of mucin. We find that duplex-oil films of bovine and human meibum at physiologic temperature reduce water evaporation only 6-8% for a 100-nm film thickness pertinent to the human tear film. Comparison to in-vivo human tear-evaporation measurements is inconclusive because evaporation from a clean-water surface is not measured and because the mass-transfer resistance is not characterized. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. High-temperature fracture toughness of duplex microstructures

    International Nuclear Information System (INIS)

    French, J.D.; Chan, H.M.; Harmer, M.P.; Miller, G.A.

    1996-01-01

    The temperature dependence of the fracture toughness of ceramics exhibiting duplex microstructures was studied relative to their single-phase constituents using two test methods: bend testing of chevron-notched beams, and the indentation-crack-length technique. The two materials systems studied were Al 2 O 3 :c-ZrO 2 (Y) and Al 2 O 3 :Y 3 Al 5 O 12 (YAG), and the testing temperature ranged from room temperature to 1,200 C. The study showed that in both systems the duplex materials showed higher toughness values than their single-phase constituents above 800 C. This result was attributed to the contribution of low-energy interphase boundaries to the overall composite toughness. Indentation crack length measurements gave toughness values and trends comparable to those determined by the chevron-notched beam method. By comparing the results of the two test methods it was possible to demonstrate that the indentation calibration constant (ξ) shows no significant temperature or material dependence. For the zirconia-containing materials, however, indentation at elevated temperatures is accompanied by significant localized plasticity, which suppressed the radial cracking. Under such conditions, some caution is warranted, since localized plasticity can lead to an overestimation of the fracture toughness

  4. Tribological behavior of duplex coating improved by ion implantation

    International Nuclear Information System (INIS)

    Kakas, D.; Skoric, B.; Rakita, M.

    2004-01-01

    In the present paper the tribological behavior of the coatings are discussed. Duplex coatings were applied on cold working steel 100Cr6. Samples were plasma nitrided at different thickness of plasma surface layers. TiN was deposited with a classic BALZERS PVD equipment and subsequent ion implantation. Ion implantation was provided with N 5+ ions. The other samples were produced with IBAD technology in DANFYSIK chamber. Wear resistance and exchanges of friction coefficient were measured with on-line test using special designed tribology equipment. Following the tests, the wear zone morphology and characteristics of surface layer structure as well as important properties were investigated by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Scratch adhesion testing was performed using commercially available equipment. Energy dispersive X-ray analysis (EDAX) of the wear-scars on pins provided essential information on the wear characteristics. In this paper some results related to influence of duplex coating production methodology on tribological behavior for cold working steel was presented

  5. Unusual Presentation of Duplex Kidneys: Ureteropelvic Junction Obstruction

    Directory of Open Access Journals (Sweden)

    Cemile Başdaş

    2016-01-01

    Full Text Available Aim. Ureteropelvic junction obstruction (UPJO is rarely associated with a duplex collecting system. We review this unusual anomaly in terms of presentation, diagnostic evaluation, and surgical management. Method. We retrospectively reviewed the medical records of patients diagnosed with a duplex system with UPJO. Result. Sixteen patients (6 girls, 10 boys with 18 moieties were treated surgically and four patients were treated conservatively. The median age at surgery was two years (range, 2 months to 7 years. The lower pole and upper moiety were affected in 12 and two kidneys, respectively, and both were affected in two patients. The anomaly was right-sided in 12 moieties and left-sided in six. The duplication was incomplete in seven patients and complete in nine. The mean renal pelvis diameter at the time of surgery was 25.6 (range 11–48 mm mm by USG. The mean renal function of the involved moiety was 28.3% before surgery. Management included pyelopyelostomy or ureteropyelostomy in six moieties, dismembered pyeloplasty in eight moieties, heminephrectomy in four cases, and simultaneous upper heminephrectomy and lower pole ureteropyelostomy in one patient. Conclusion. There is no standard approach for these patients and treatment should be individualized according to physical presentation, detailed anatomy, and severity of obstruction.

  6. Microstructural characterization of thermally-aged duplex stainless steels

    International Nuclear Information System (INIS)

    Nomoto, A.; Hamaoka, T.; Nishida, K.; Dohi, K.; Soneda, N.

    2011-01-01

    The embrittlement of duplex stainless steels is of concern for the long term operation of light water reactors. The objectives of this work was to characterize solute atom distribution in ferrite phase of thermally aged duplex stainless steels by using atom tomography probe and to measure the hardness of ferrite phase by using nano-indentation technique. This series of slides highlights 4 main conclusions. First, phase separation quickly evolves and then slows down during the thermal ageing. Secondly, precipitates are formed after ageing for 1000 hr at 400 C and 2000 hr at 350 C. The clusters become larger with time at 400 C. Chemical composition of the clusters do not change very much with cluster size and ageing time at 400 C. Thirdly, no cluster formation is observed in the materials aged at 450 C. It is likely that precipitation occurs faster than phase separation at lower temperatures. Fourthly, hardness changes are well described by combining the contributions of phase separation and G phase formation. 'Variation' is a good parameter to describe hardness change due to phase separation. Contribution of G-phase needs to be considered separately

  7. Duplex Alu Screening for Degraded DNA of Skeletal Human Remains

    Directory of Open Access Journals (Sweden)

    Fabian Haß

    2017-10-01

    Full Text Available The human-specific Alu elements, belonging to the class of Short INterspersed Elements (SINEs, have been shown to be a powerful tool for population genetic studies. An earlier study in this department showed that it was possible to analyze Alu presence/absence in 3000-year-old skeletal human remains from the Bronze Age Lichtenstein cave in Lower Saxony, Germany. We developed duplex Alu screening PCRs with flanking primers for two Alu elements, each combined with a single internal Alu primer. By adding an internal primer, the approximately 400–500 bp presence signals of Alu elements can be detected within a range of less than 200 bp. Thus, our PCR approach is suited for highly fragmented ancient DNA samples, whereas NGS analyses frequently are unable to handle repetitive elements. With this analysis system, we examined remains of 12 individuals from the Lichtenstein cave with different degrees of DNA degradation. The duplex PCRs showed fully informative amplification results for all of the chosen Alu loci in eight of the 12 samples. Our analysis system showed that Alu presence/absence analysis is possible in samples with different degrees of DNA degradation and it reduces the amount of valuable skeletal material needed by a factor of four, as compared with a singleplex approach.

  8. Duplex-imprinted nano well arrays for promising nanoparticle assembly

    Science.gov (United States)

    Li, Xiangping; Manz, Andreas

    2018-02-01

    A large area nano-duplex-imprint technique is presented in this contribution using natural cicada wings as stamps. The glassy wings of the cicada, which are abundant in nature, exhibit strikingly interesting nanopillar structures over their membrane. This technique, with excellent performance despite the nonplanar surface of the wings, combines both top-down and bottom-up nanofabrication techniques. It transitions micro-nanofabrication from a cleanroom environment to the bench. Two different materials, dicing tape with an acrylic layer and a UV optical adhesive, are used to make replications at the same time, thus achieving duplex imprinting. The promise of a large volume of commercial manufacturing of these nanostructure elements can be envisaged through this contribution to speeding up the fabrication process and achieving a higher throughput. The contact angle of the replicated nanowell arrays before and after oxygen plasma was measured. Gold nanoparticles (50 nm) were used to test how the nanoparticles behaved on the untreated and plasma-treated replica surface. The experiments show that promising nanoparticle self-assembly can be obtained.

  9. Study of Sigma Phase in Duplex SAF 2507

    Science.gov (United States)

    Fellicia, D. M.; Sutarsis; Kurniawan, B. A.; Wulanari, D.; Purniawan, A.; Wibisono, A. T.

    2017-05-01

    Super duplex stainless steel is one of the stainless steel which has a combination between high strength properties and excellent corrosion resistance. However, the resistance can decrease by precipitation of sigma phase which is formed at high temperature, for example after welding processes. A series of experiments has been performed to study the effect of solution annealing to existence of sigma phase on super duplex SAF 2507. Variations of solution-annealing temperatures were 1000 °C, 1065 °C and 1125 °C with holding time of 15 and 30 minutes for each temperature. Effect of solution annealing process was characterized by using XRD, SEM, and Optical Microscopy. The result showed precipitation of sigma phase completely dissolved at 1065 °C and 1125 °C because it reformed to austenite. After it was heated at 1065 °C, chromium carbide appeared in ferrite site and grain boundary. The amount of chromium carbide increased with the increasing of solution annealing temperature.

  10. Duplex Identification of Staphylococcus aureus by Aptamer and Gold Nanoparticles.

    Science.gov (United States)

    Chang, Tianjun; Wang, Libo; Zhao, Kexu; Ge, Yu; He, Meng; Li, Gang

    2016-06-01

    Staphylococcus aureus is the top common pathogen causing infections and food poisoning. Identification of S. aureus is crucial for the disease diagnosis and regulation of food hygiene. Herein, we report an aptamer-AuNPs based method for duplex identification of S. aureus. Using AuNPs as an indicator, SA23, an aptamer against S. aureus, can well identify its target from Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa. Furthermore, we find citrate-coated AuNPs can strongly bind to S. aureus, but not bind to Salmonella enterica and Proteus mirabilis, which leads to different color changes in salt solution. This colorimetric response is capable of distinguishing S. aureus from S. enteritidis and P. mirabilis. Thus, using the aptasensor and AuNPs together, S. aureus can be accurately identified from the common pathogens. This duplex identification system is a promising platform for simple visual identification of S. aureus. Additionally, in the aptasensing process, bacteria are incubated with aptamers and then be removed before the aptamers adding to AuNPs, which may avoid the interactions between bacteria and AuNPs. This strategy can be potentially applied in principle to detect other cells by AuNPs-based aptasensors.

  11. Stress corrosion cracking of duplex stainless steels in caustic solutions

    Science.gov (United States)

    Bhattacharya, Ananya

    Duplex stainless steels (DSS) with roughly equal amount of austenite and ferrite phases are being used in industries such as petrochemical, nuclear, pulp and paper mills, de-salination plants, marine environments, and others. However, many DSS grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides and sulfide-containing caustic solutions. Although stress corrosion cracking of duplex stainless steels in chloride solution has been investigated and well documented in the literature but the SCC mechanisms for DSS in caustic solutions were not known. Microstructural changes during fabrication processes affect the overall SCC susceptibility of these steels in caustic solutions. Other environmental factors, like pH of the solution, temperature, and resulting electrochemical potential also influence the SCC susceptibility of duplex stainless steels. In this study, the role of material and environmental parameters on corrosion and stress corrosion cracking of duplex stainless steels in caustic solutions were investigated. Changes in the DSS microstructure by different annealing and aging treatments were characterized in terms of changes in the ratio of austenite and ferrite phases, phase morphology and intermetallic precipitation using optical micrography, SEM, EDS, XRD, nano-indentation and microhardness methods. These samples were then tested for general and localized corrosion susceptibility and SCC to understand the underlying mechanisms of crack initiation and propagation in DSS in the above-mentioned environments. Results showed that the austenite phase in the DSS is more susceptible to crack initiation and propagation in caustic solutions, which is different from that in the low pH chloride environment where the ferrite phase is the more susceptible phase. This study also showed that microstructural changes in duplex stainless steels due to different heat treatments could affect their SCC

  12. Half-Duplex and Full-Duplex AF and DF Relaying with Energy-Harvesting in Log-Normal Fading

    KAUST Repository

    Rabie, Khaled M.

    2017-08-15

    Energy-harvesting (EH) and wireless power transfer in cooperative relaying networks have recently attracted a considerable amount of research attention. Most of the existing work on this topic however focuses on Rayleigh fading channels, which represent outdoor environments. In contrast, this paper is dedicated to analyze the performance of dual-hop relaying systems with EH over indoor channels characterized by log-normal fading. Both half-duplex (HD) and full-duplex (FD) relaying mechanisms are studied in this work with decode-and-forward (DF) and amplify-and-forward (AF) relaying protocols. In addition, three EH schemes are investigated, namely, time switching relaying, power splitting relaying and ideal relaying receiver which serves as a lower bound. The system performance is evaluated in terms of the ergodic outage probability for which we derive accurate analytical expressions. Monte Carlo simulations are provided throughout to validate the accuracy of our analysis. Results reveal that, in both HD and FD scenarios, AF relaying performs only slightly worse than DF relaying which can make the former a more efficient solution when the processing energy cost at the DF relay is taken into account. It is also shown that FD relaying systems can generally outperform HD relaying schemes as long as the loop-back interference in FD is relatively small. Furthermore, increasing the variance of the log-normal channel has shown to deteriorate the performance in all the relaying and EH protocols considered.

  13. Cy3 and Cy5 dyes attached to oligonucleotide terminus stabilize DNA duplexes: predictive thermodynamic model.

    Science.gov (United States)

    Moreira, Bernardo G; You, Yong; Owczarzy, Richard

    2015-03-01

    Cyanine dyes are important chemical modifications of oligonucleotides exhibiting intensive and stable fluorescence at visible light wavelengths. When Cy3 or Cy5 dye is attached to 5' end of a DNA duplex, the dye stacks on the terminal base pair and stabilizes the duplex. Using optical melting experiments, we have determined thermodynamic parameters that can predict the effects of the dyes on duplex stability quantitatively (ΔG°, Tm). Both Cy dyes enhance duplex formation by 1.2 kcal/mol on average, however, this Gibbs energy contribution is sequence-dependent. If the Cy5 is attached to a pyrimidine nucleotide of pyrimidine-purine base pair, the stabilization is larger compared to the attachment to a purine nucleotide. This is likely due to increased stacking interactions of the dye to the purine of the complementary strand. Dangling (unpaired) nucleotides at duplex terminus are also known to enhance duplex stability. Stabilization originated from the Cy dyes is significantly larger than the stabilization due to the presence of dangling nucleotides. If both the dangling base and Cy3 are present, their thermodynamic contributions are approximately additive. New thermodynamic parameters improve predictions of duplex folding, which will help design oligonucleotide sequences for biophysical, biological, engineering, and nanotechnology applications. Copyright © 2015. Published by Elsevier B.V.

  14. Analysis of Structural Flexibility of Damaged DNA Using Thiol-Tethered Oligonucleotide Duplexes.

    Directory of Open Access Journals (Sweden)

    Masashi Fujita

    Full Text Available Bent structures are formed in DNA by the binding of small molecules or proteins. We developed a chemical method to detect bent DNA structures. Oligonucleotide duplexes in which two mercaptoalkyl groups were attached to the positions facing each other across the major groove were prepared. When the duplex contained the cisplatin adduct, which was proved to induce static helix bending, interstrand disulfide bond formation under an oxygen atmosphere was detected by HPLC analyses, but not in the non-adducted duplex, when the two thiol-tethered nucleosides were separated by six base pairs. When the insert was five and seven base pairs, the disulfide bond was formed and was not formed, respectively, regardless of the cisplatin adduct formation. The same reaction was observed in the duplexes containing an abasic site analog and the (6–4 photoproduct. Compared with the cisplatin case, the disulfide bond formation was slower in these duplexes, but the reaction rate was nearly independent of the linker length. These results indicate that dynamic structural changes of the abasic site- and (6–4 photoproduct-containing duplexes could be detected by our method. It is strongly suggested that the UV-damaged DNA-binding protein, which specifically binds these duplexes and functions at the first step of global-genome nucleotide excision repair, recognizes the easily bendable nature of damaged DNA.

  15. Selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty with duplex scanning

    International Nuclear Information System (INIS)

    Bostroem Ardin, A.; Hellberg, A.; Ljungman, C.; Logason, K.; Karacagil, S.; Loefberg, A.M.; Andren, B.

    2002-01-01

    Aim: To evaluate the role of duplex scanning in the selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty (PTA). Material and Methods: From January 1995 through May 2000, 702 patients (952 limbs), with chronic lower extremity ischemia due to infrainguinal atherosclerotic disease diagnosed by duplex scanning, were retrospectively studied. Diagnostic angiography (130 limbs) or infrainguinal PTA (108 limbs) was performed in 238 limbs. Two investigators retrospectively analyzed the duplex examinations and angiographies in a blinded manner and used similar criteria for the interpretation of lesions suitable or not suitable for PTA. Results: The superficial femoral, popliteal and crural artery lesions were correctly selected for PTA in 85%, 66% and 32%, respectively. The accuracy, sensitivity, specificity, negative predictive value and positive predictive value of duplex scanning to appropriately categorize femoropopliteal lesions as suitable or unsuitable for PTA were 89%, 83%, 92%, 94% and 78%, respectively. The accuracy of duplex scanning for predicting the performance of infrainguinal PTA was 83%. Conclusion: Duplex scanning has an important impact on the selection of treatment modalities in limbs with infrainguinal arterial occlusive disease. Femoropopliteal lesions can be reliably selected to PTA according to duplex scan findings

  16. [A Duplex PCR Method for Detection of Babesia caballi and Theileria equi].

    Science.gov (United States)

    Zhang, Yang; Zhang, Yu-ting; Wang, Zhen-bao; Bolati; Li, Hai; Bayinchahan

    2015-04-01

    To develop a duplex PCR assay for detection of Babesia caballi and Theileria equi. Two pairs of primers were designed according to the BC48 gene of B. caballi and 18 s rRNA gene of T. equi, and a duplex PCR assay was developed by the optimization of reaction conditions. The specificity, sensitivity and reliability of the method were tested. The horse blood samples of suspected cases were collected from Yili region, and detected by the duplex PCR, microspopy, conventional PCR, and fluorescence quantitative PCR, and the results were compared. Using the duplex PCR assay, the specific fragments of 155 bp and 280 bp were amplified from DNA samples of B. caballi and T. equi, respectively. No specific fragment was amplified from DNA samples of B. bigemina, Theilerdia annulata, Theilerdia sergenti, Toxoplasma gondii, Neospora caninum, and Trypanosoma evansi. The limit of detection was 4.85 x 10(5) copies/L for B. caballi DNA and 4.85 x 10(4) copies/µl for T. equi DNA, respectively. Among the 24 blood samples, 11 were found B. caballi-positive by the duplex PCR assay, and 18 were T. equi-positive. The coincidence rate of microscopy, conventional PCR, and fluorescence quantitative PCR with duplex PCR was 91.7% (22/24), 95.8% (23/24), and 95.8% (23/24), respectively. A duplex PCR assay for simultaneous detection of B. caballi and T. equi is established.

  17. Assessing the effect of different operation techniques on postoperative duplex ultrasound quality after carotid endarterectomy.

    Science.gov (United States)

    Grambow, E; Heller, T; Wieneke, P; Weiß, C; Klar, E; Weinrich, M

    2018-01-01

    Duplex ultrasound is the first choice in diagnostics and surveillance of stenoses of the internal carotid arteries before and even after surgery. Therefore, the quality of duplex ultrasound is crucial to investigate these vascular pathologies. Aim of this study was the evaluation whether different surgical techniques affect the postoperative quality of duplex ultrasound. In a time period from January to May 2015 duplex ultrasound of the cervical vessels was performed in 75 patients after unilateral endarterectomy of the internal carotid artery at our department between 2006 and 2012. Thereby, the non-operated contralateral side served as a control. Study groups were defined by the surgical techniques of eversion- or thrombendarterectomy with patch plasty using different patch materials and/or a haemostatic sealant. Duplex ultrasound analysis included acoustic impedance, extinction of ultrasound, thickness of skin and individual anatomic aspects of the patients. Carotid endarterectomy itself reduced intravascular grey levels, skin thickness and increased extinction of duplex ultrasound when compared to the non-operated side of the neck. In contrast, neither the kind of chosen operative technique nor the use of different patch materials or the application of a haemostatic sealant showed an effect in this regards. Whereas carotid endarterectomy per se worsens the quality of postoperative duplex ultrasound, the different analysed surgical techniques as well as used patches and the application of a haemostatic sealant can be assumed to be equal regarding the quality of postoperative ultrasound.

  18. l-Proline and RNA Duplex m-Value Temperature Dependence.

    Science.gov (United States)

    Schwinefus, Jeffrey J; Baka, Nadia L; Modi, Kalpit; Billmeyer, Kaylyn N; Lu, Shutian; Haase, Lucas R; Menssen, Ryan J

    2017-08-03

    The temperature dependence of l-proline interactions with the RNA dodecamer duplex surface exposed after unfolding was quantified using thermal and isothermal titration denaturation monitored by uv-absorbance. The m-value quantifying proline interactions with the RNA duplex surface area exposed after unfolding was measured using RNA duplexes with GC content ranging between 17 and 83%. The m-values from thermal denaturation decreased with increasing GC content signifying increasingly favorable proline interactions with the exposed RNA surface area. However, m-values from isothermal titration denaturation at 25.0 °C were independent of GC content and less negative than those from thermal denaturation. The m-value from isothermal titration denaturation for a 50% GC RNA duplex decreased (became more negative) as the temperature increased and was in nearly exact agreement with the m-value from thermal denaturation. Since RNA duplex transition temperatures increased with GC content, the more favorable proline interactions with the high GC content duplex surface area observed from thermal denaturation resulted from the temperature dependence of proline interactions rather than the RNA surface chemical composition. The enthalpy contribution to the m-value was positive and small (indicating a slight increase in duplex unfolding enthalpy with proline) while the entropic contribution to the m-value was positive and increased with temperature. Our results will facilitate proline's use as a probe of solvent accessible surface area changes during biochemical reactions at different reaction temperatures.

  19. NMR studies of abasic sites in DNA duplexes: Deoxyadenosine stacks into the helix opposite acyclic lesions

    International Nuclear Information System (INIS)

    Kalnik, M.W.; Chang, Chienneng; Johnson, F.; Grollman, A.P.; Patel, D.J.

    1989-01-01

    Proton and phosphorus NMR studies are reported for two complementary nonanucleotide duplexes containing acyclic abasic sites. The first duplex, d(C-A-T-G-A-G-T-A-C)·d(G-T-A-C-P-C-A-T-G), contains an acyclic propanyl moiety, P, located opposite a deoxyadenosine at the center of the helix (designated AP P 9-mer duplex). The second duplex, d(C-A-T-G-A-G-T-A-C-)·d(G-T-A-C-E-C-A-T-G), contains a similarly located acyclic ethanyl moiety, E (designated AP E 9-mer duplex). The ethanyl moiety is one carbon shorter than the natural carbon-phosphodiester backbone of a single nucleotide unit of DNA. The majority of the exchangeable and nonexchangeable base and sugar protons in both the AP P 9-mer and AP E 9-mer duplexes, including those at the abasic site, have been assigned by recording and analyzing two-dimensional phase-sensitive NOESY data sets in H 2 O and D 2 O solution between -5 and 5 degree C. These spectroscopic observations establish that A5 inserts into the helix opposite the abasic site (P14 and El14) and stacks between the flanking G4·C15 and G6·C13 Watson-Crick base pairs in both the AP P 9-mer and AP E 9-mer duplexes. Proton NMR parameters for the Ap P 9-mer and AP E 9-mer duplexes are similar to those reported previously. These proton NMR experiments demonstrate that the structures at abasic sites are very similar whether the five-membered ring is open or closed or whether the phosphodiester backbone is shortened by one carbon atom. Phosphorus spectra of the AP P 9-mer and AP E 9-mer duplexes (5 degree C) indicate that the backbone conformation is similarly perturbed at three phosphodiester backbone torsion angles

  20. Base Pair Opening in a Deoxynucleotide Duplex Containing a cis-syn Thymine Cyclobutane Dimer Lesion

    Science.gov (United States)

    Wenke, Belinda B.; Huiting, Leah N.; Frankel, Elisa B.; Lane, Benjamin F.; Núñez, Megan E.

    2014-01-01

    The cis-syn thymine cyclobutane dimer is a DNA photoproduct implicated in skin cancer. We compared the stability of individual base pairs in thymine dimer-containing duplexes to undamaged parent 10-mer duplexes. UV melting thermodynamic measurements, CD spectroscopy, and 2D NOESY NMR spectroscopy confirm that the thymine dimer lesion is locally and moderately destabilizing within an overall B-form duplex conformation. We measured the rates of exchange of individual imino protons by NMR using magnetization transfer from water and determined the equilibrium constant for the opening of each base pair Kop. In the normal duplex Kop decreases from the frayed ends of the duplex toward the center, such that the central TA pair is the most stable with a Kop of 8×10−7. In contrast, base pair opening at the 5’T of the thymine dimer is facile. The 5’T of the dimer has the largest equilibrium constant (Kop =3×10−4) in its duplex, considerably larger than even the frayed penultimate base pairs. Notably, base pairing by the 3’T of the dimer is much more stable than by the 5’T, indicating that the predominant opening mechanism for the thymine dimer lesion is not likely to be flipping out into solution as a single unit. The dimer asymmetrically affects the stability of the duplex in its vicinity, destabilizing base pairing on its 5’ side more than on the 3’ side. The striking differences in base pair opening between parent and dimer duplexes occur independently of the duplex-single strand melting transitions. PMID:24328089

  1. Renal damage in vesicoureteral reflux associated to duplex systems

    International Nuclear Information System (INIS)

    Orellana, P.; Velasquez, C.; Baquedano, P.

    2002-01-01

    Duplex system (DS) is a common occurrence and it can be associated to a range of ureteral and renal anomalies draining the two poles of the duplex kidneys, as vesicoureteral reflux (VUR) in the lower moiety and ureterocele in the upper moiety. The VUR in a duplex system can be primary or secondary (associated to an ureterocele). The assessment of parenchymal uptake and function of the whole and separate parts of the kidneys is important for therapeutical decisions. Objective: To determine the presence of renal damage, by dimercaptosuccinic acid (DMSA) scintigraphy in children with a refluxing DS and if there any difference between primary and secondary reflux. Patients and Methods: 36 children; 23 girls and 13 boys, with VUR into completely duplicated collecting systems was studied retrospectively (37 RU with DS, 35 unilateral and 1 bilateral), with a mean age of 2.43 y.o. (range: 1 month-11y.o.). All of the children underwent ultrasonography, voiding cystourethrogram and renal static scintigraphy. Among the 37 RU with VUR, 25 had primary VUR and 12 had VUR secondary to the presence of an ureterocele. Ten out of the 36 children (27.8%) were evaluated due to antenatal diagnosis and the remaining 26 (72.2%) after urinary tract infection (UTI). Results: Seventy percent of the 37 RU with VUR into completely duplicated collecting systems had renal damage demonstrated by renal static scintigraphy. Among the 25 RU with primary VUR, 19 (76%) had renal damage, 6 with a complete absence of function in the lower moiety. In this group, 80% of children was studied due to an UTI at a mean age of 3.3 y.o. In the group of children with secondary VUR, we observed a lower moiety with renal damage in 6/12 (50%), in 4 of them associated with an abnormal upper moiety. 7 out of 12 children (58.3%) had an abnormal upper moiety, 4 of them with a damage in lower moiety too. One children presented with renal exclusion. Half of these children were studied due to UTI, at a mean age of 1 y

  2. Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

    Directory of Open Access Journals (Sweden)

    ENCENG SULAEMAN

    2017-06-01

    Full Text Available ABSTRAK Kebutuhan akan komunikasi bergerak semakin mengalami peningkatan dalam dunia teknologi yang ada saat ini, maka hadirlah teknologi terbaru yaitu Long Term Evolution (LTE. Dengan teknik duplex jenis Frequency Division Duplex (FDD, dirancanglah duplexer yang mampu melakukan proses pengiriman dan penerimaan dalam satu waktu dengan frekuensi yang berbeda antara uplink dan downlink. Pada penelitian ini dirancang dan diimplementasikan sebuah duplekser dengan menggunakan metoda Hybrid Coupler dan Bandstop Filter berbasis Split Ring Resonator untuk band frekuensi ke-7 pada teknologi LTE di sisi Base Transceiver Station (BTS. Duplekser dibuat dengan menggabungkan dua buah hybrid Coupler dan dua buah Bandstop Filter. Hasil pengukuran duplexer saat port Tx mengirimkan sinyal ke antena dengan nilai redaman pada frekuensi tengah downlink sebesar 3.168 dB. Lalu pada saat antena menerima sinyal untuk diteruskan ke Rx terdapat redaman di frekuensi tengah uplink sebesar 6 dB. Sedangkan untuk isolasi dari port Tx-port Rx dihasilkan sebesar 15 dB. Kata kunci: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, dan Long Term Evolution. ABSTRACT The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 d

  3. The effects of laser welding parameters on the microstructure of ferritic and duplex stainless steels welds

    Science.gov (United States)

    Pekkarinen, J.; Kujanpää, V.

    This study is focused to determine empirically, which microstructural changes occur in ferritic and duplex stainless steels when heat input is controlled by welding parameters. Test welds were done autogenously bead-on-plate without shielding gas using 5 kW fiber laser. For comparison, some gas tungsten arc welds were made. Used test material were 1.4016 (AISI 430) and 1.4003 (low-carbon ferritic) type steels in ferritic steels group and 1.4162 (low-alloyed duplex, LDX2101) and 1.4462 (AISI 2205) type steels in duplex steels group. Microstructural changes in welds were identified and examined using optical metallographic methods.

  4. Metallurgical Changes During Welding of Duplex Stainless Steel

    International Nuclear Information System (INIS)

    SLLam, Y.A.A.

    2004-01-01

    The aim of this study is to investigate the influence of the cooling rates on the transformation behavior of a duplex stainless steel deposited weld metal, subjected to isothermal heat treatments in the temperature range between 400 C to 700 C, for different aging times. cooling rates (air cooling, furnace cooling, and water quenching) followed all heat treatments. the effect of aging time on the ferrite content, and hardness value of the weld metal samples, for these cooling rates, and aging temperatures were evaluated. the ferrite content decreased and hardness value increased by increasing aging time. the microstructure of the weld metal in both as welded and isothermally heat-treated conditions has been investigated using optical microscopy, and X-ray diffraction techniques

  5. Investigation of Cr-Ni duplex stainless steel

    International Nuclear Information System (INIS)

    Lu Shiying

    1985-01-01

    At temperatures of 450 - 750 0 C, a laminate-shaped intermetallic phase Fe3Cr3Mo2Si2 has been observed. Intergranular brittle fracture is due to the precipitation of the Fe3Cr3Mo2SI2 phase, but quasi-cleavage fracture is connected with the precipitation of chi and σ phases. The formation of chi and σ during aging at 750 - 900 0 C results in a drastic decrease of the SCC resistance of Cr18Ni5 steel. In order to avoid a fully ferritic microstructure in Cr18Ni5 duplex steel after heating at high temperature or welding, the K value must be kept to 0.42 for thin wall tube. The decrease in SCC resistance after cold deformation is not due to the formation of strain-induced martensite but is connected with significant reduction in the resistance to pitting corrosion. (author)

  6. A performance analysis in AF full duplex relay selection network

    Science.gov (United States)

    Ngoc, Long Nguyen; Hong, Nhu Nguyen; Loan, Nguyen Thi Phuong; Kieu, Tam Nguyen; Voznak, Miroslav; Zdralek, Jaroslav

    2018-04-01

    This paper studies on the relaying selective matter in amplify-and-forward (AF) cooperation communication with full-duplex (FD) activity. Various relay choice models supposing the present of different instant information are investigated. We examine a maximal relaying choice that optimizes the instant FD channel capacity and asks for global channel state information (CSI) as well as partial CSI learning. To make comparison easy, accurate outage probability clauses and asymptote form of these strategies that give a diversity rank are extracted. From that, we can see clearly that the number of relays, noise factor, the transmittance coefficient as well as the information transfer power had impacted on their performance. Besides, the optimal relay selection (ORS) model can promote than that of the partial relay selection (PRS) model.

  7. Tool wear analysis during duplex stainless steel trochoidal milling

    Science.gov (United States)

    Amaro, Paulo; Ferreira, Pedro; Simões, Fernando

    2018-05-01

    In this study a tool with interchangeable inserts of sintered carbides coated with AlTiN were used to mill a duplex stainless steel with trochoidal strategies. Cutting speed range from 120 to 300 m/min were used and t he evaluation of tool deterioration and tool life was made according international standard ISO 8688-1. It was observed a progressive development of a flank wear and a cumulative cyclic process of localized adhesion of the chip to the cutting edge, followed by chipping, loss of the coating and substrate exposure. The tool life reached a maximum of 35 min. for cutting speed of 120 m/min. However, it was possible to maintain a tool life of 20-25 minutes when the cutting speed was increased up to 240 m/min.

  8. Technology of Welding Joints Mixed with Duplex Steel

    Directory of Open Access Journals (Sweden)

    Słania J.

    2016-03-01

    Full Text Available Results of the examinations of sample plates of mixed joints with the duplex steel were discussed. Examinations were taken on the sample plates of mixed joints of sheet plates type P355NL1 and X2CrNiMoN22-5-3 welded by the flux-cored wire DW-329A by the Kobelco company of the following category T 22 9 3 NL RC/M3 in the gas shroud M21 (Ar+18%CO2 (plate no.1, and nickel covered electrodes E Ni 6082 by the Böhler company (plate no. 2. Results of the side bend test of welded joint, transverse tensile test, stretching of the weld metal, impact strength, micro and macroscopic metallographic examinations, and measurements of the delta ferrite content were presented.

  9. Hydrogen effects in duplex stainless steel welded joints - electrochemical studies

    Science.gov (United States)

    Michalska, J.; Łabanowski, J.; Ćwiek, J.

    2012-05-01

    In this work results on the influence of hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel (DSS) welded joints are described. The results were discussed by taking into account three different areas on the welded joint: weld metal (WM), heat-affected zone (HAZ) and parent metal. The corrosion resistance was qualified with the polarization curves registered in a synthetic sea water. The conclusion is that, hydrogen may seriously deteriorate the passive film stability and corrosion resistance to pitting of 2205 DSS welded joints. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen degradation was dependent on the hydrogen charging conditions. WM region has been revealed as the most sensitive to hydrogen action.

  10. Electromagnetic non-destructive technique for duplex stainless steel characterization

    Science.gov (United States)

    Rocha, João Vicente; Camerini, Cesar; Pereira, Gabriela

    2016-02-01

    Duplex stainless steel (DSS) is a two-phase (ferrite and austenite) material, which exhibits an attractive combination of mechanical properties and high corrosion resistance, being commonly employed for equipment of petrochemical plants, refining units and oil & gas platforms. The best properties of DSS are achieved when the phases are in equal proportions. However, exposition to high temperatures (e.g. welding process) may entail undesired consequences, such as deleterious phases precipitation (e.g. sigma, chi) and different proportion of the original phases, impairing dramatically the mechanical and corrosion properties of the material. A detailed study of the magnetic behavior of DSS microstructure with different ferrite austenite ratios and deleterious phases content was accomplished. The non destructive method evaluates the electromagnetic properties changes in the material and is capable to identify the presence of deleterious phases into DSS microstructure.

  11. Modern high strength QT, TM and duplex-stainless steels

    International Nuclear Information System (INIS)

    Bocquet, P.; Luxenburger, G.; Porter, D.; Ericsson, C.

    2003-01-01

    Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

  12. Multicenter assessment of venous reflux by duplex ultrasound.

    Science.gov (United States)

    Lurie, Fedor; Comerota, Anthony; Eklof, Bo; Kistner, Robert L; Labropoulos, Nicos; Lohr, Joann; Marston, William; Meissner, Mark; Moneta, Gregory; Neglén, Peter; Neuhardt, Diana; Padberg, Frank; Welsh, Harold J

    2012-02-01

    This prospective multicenter investigation was conducted to define the repeatability of duplex-based identification of venous reflux and the relative effect of key parameters on the reproducibility of the test. Repeatability was studied by having the same technologist perform duplicate tests, at the same time of the day, using the same reflux-provoking maneuver and with the patient in the same position. Reproducibility was examined by having two different technologists perform the test at the same time of the day, using the same reflux-provoking maneuver and with the patient in the same position. Facilitated reproducibility was studied by having two different technologists examine the same patients immediately after an educational intervention. Limits of agreement between two duplex scans were studied by changing three elements of the test: time of the day (morning vs afternoon), patient's position (standing vs supine), and reflux initiation (manual vs automatic compression-decompression). The study enrolled 17 healthy volunteers and 57 patients with primary chronic venous disease. Repeatability of reflux time measurements in deep veins did not significantly differ with the time of day, the patient's position, or the reflux-provoking maneuver. Reflux measurements in the superficial veins were more repeatable (P ultrasound detection of venous reflux. Reports should include information on the time of the test, the patient's position, and the provoking maneuver used. Adopting a uniform cut point of 0.5 second for pathologic reflux can significantly improve the reliability of reflux detection. Implementation of a standard protocol should elevate the minimal standard for agreement between repeated tests from the current 70% to at least 80% and with more rigid standardization, to 90%. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  13. Formation of Nitrogen Bubbles During Solidification of Duplex Stainless Steels

    Science.gov (United States)

    Dai, Kaiju; Wang, Bo; Xue, Fei; Liu, Shanshan; Huang, Junkai; Zhang, Jieyu

    2018-04-01

    The nucleation and growth of nitrogen bubbles for duplex stainless steels are of great significance for the formation mechanism of bubbles during solidification. In the current study, numerical method and theoretical analysis of formula derivation were used to study the formation of nitrogen bubbles during solidification. The critical sizes of the bubble for homogeneous nucleation and heterogeneous nucleation at the solid-liquid interface during solidification were derived theoretically by the classical nucleation theory. The results show that the calculated values for the solubility of nitrogen in duplex stainless steel are in good agreement with the experimental values which are quoted by references: for example, when the temperature T = 1823 K and the nitrogen partial pressure P_{{N2 }} = 40P^{Θ} , the calculated value (0.8042 wt pct) for the solubility of Fe-12Cr alloy nitrogen in molten steel is close to the experimental value (0.780 wt pct). Moreover, the critical radii for homogeneous nucleation and heterogeneous nucleation are identical during solidification. On the one hand, with the increasing temperature or the melt depth, the critical nucleation radius of bubbles at the solid-liquid interface increases, but the bubble growth rate decreases. On the other hand, with the decreasing initial content of nitrogen or the cooling rate, the critical nucleation radius of bubbles at the solid-liquid interface increases, but the bubble growth rate decreases. Furthermore, when the melt depth is greater than the critical depth, which is determined by the technological conditions, the change in the Gibbs free energy for the nucleation is not conducive enough to form new bubbles.

  14. Duplex/quadruplex oligonucleotides: Role of the duplex domain in the stabilization of a new generation of highly effective anti-thrombin aptamers.

    Science.gov (United States)

    Russo Krauss, Irene; Napolitano, Valeria; Petraccone, Luigi; Troisi, Romualdo; Spiridonova, Vera; Mattia, Carlo Andrea; Sica, Filomena

    2018-02-01

    Recently, mixed duplex/quadruplex oligonucleotides have attracted great interest for use as biomedical aptamers. In the case of anti-thrombin aptamers, the addition of duplex-forming sequences to a G-quadruplex module identical or very similar to the best-known G-quadruplex of the Thrombin Binding Aptamer (HD1) results in new or improved biological properties, such as higher activity or different recognition properties with respect to HD1. Remarkably, this bimodular fold was hypothesized, based on its sequence, for the only anti-thrombin aptamer in advanced clinical trial, NU172. Whereas cation modulation of G-quadruplex conformation and stability is well characterized, only few data from similar analysis on duplex/quadruplex oligonucleotides exist. Here we have performed a characterization of structure and stability of four different duplex/quadruplex anti-thrombin aptamers, including NU172, in the presence of different cations and in physiological-mimicking conditions in comparison to HD1, by means of spectroscopic techniques (UV and circular dichroism) and differential scanning calorimetry. Our data show a strong reciprocal influence of each domain on the stability of the other and in particular suggest a stabilizing effect of the duplex region in the presence of solutions mimicking the physiological conditions, strengthening the idea that bimodular aptamers present better therapeutic potentialities than those containing a single G-quadruplex domain. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Breaking the Transmitter-Receiver Isolation Barrier in Mobile Handsets with Spatial Duplexing

    DEFF Research Database (Denmark)

    Alrabadi, Osama; Tatomirescu, Alexandru; Knudsen, Mikael

    2013-01-01

    In full-duplex radio communication systems like eUTRAN, CDMA-2000, the radio transmitter (Tx) is active at the same time as the radio receiver (Rx). The Tx and the Rx will be using separate dedicated frequency bands and the Tx-Rx isolation is ensured by duplex filters. However, agile duplexers...... required for multiband operation are almost non-existent while dedicating a bank of narrowband filters is bulky and incurs considerable switching losses. In this article we propose an approach that dramatically reduces the complexity of the RF frontend, first by replacing the duplex filter with a spatial...... frequency bands as long as the antennas are made tunable. Moreover, the spatial filter may directly benefit from the balanced architecture of the power amplifiers (PAs) thus reducing the total system complexity and insertion loss. Finally, simulation and initial measurement results are provided...

  16. In-Band α-Duplex Scheme for Cellular Networks: A Stochastic Geometry Approach

    KAUST Repository

    Alammouri, Ahmad; Elsawy, Hesham; Amin, Osama; Alouini, Mohamed-Slim

    2016-01-01

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink

  17. Duplex sonography in the planning and evaluation of arteriovenous fistulae for haemodialysis

    International Nuclear Information System (INIS)

    Kerr, S.F.; Krishan, S.; Lapham, R.C.; Weston, M.J.

    2010-01-01

    This paper describes how to perform duplex sonography in the planning and evaluation of arteriovenous fistulae in haemodialysis patients, discusses its roles in these settings, and presents a review of commonly encountered complications.

  18. Duplex evaluation following femoropopliteal angioplasty and stenting: criteria and utility of surveillance.

    Science.gov (United States)

    Baril, Donald T; Marone, Luke K

    2012-07-01

    Surveillance following lower extremity bypass, carotid endarterectomy, and endovascular aortic aneurysm repair has become the standard of care at most institutions. Conversely, surveillance following lower extremity endovascular interventions is performed somewhat sporadically in part because the duplex criteria for recurrent stenoses have been ill defined. It appears that duplex surveillance after peripheral endovascular interventions, as with conventional bypass, is beneficial in identifying recurrent lesions which may preclude failure and occlusion. In-stent stenosis following superficial femoral artery angioplasty and stenting can be predicted by both peak systolic velocity and velocity ratio data as measured by duplex ultrasound. Duplex criteria have been defined to determine both ≥50% in-stent stenosis and ≥80% in-stent stenosis. Although not yet well studied, it appears that applying these criteria during routine surveillance may assist in preventing failure of endovascular interventions.

  19. Can Full Duplex reduce the discovery time in D2D Communication?

    DEFF Research Database (Denmark)

    Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

    2016-01-01

    Device-to-device (D2D) communication is considered as one of the key technologies to support new types of services, such as public safety and proximity-based applications. D2D communication requires a discovery phase, i.e., the node awareness procedure prior to the communication phase. Conventional...... half duplex transmission may not be sufficient to provide fast discovery and cope with the strict latency targets of future 5G services. On the other hand, in-band full duplex, by allowing simultaneous transmission and reception, may complete the discovery phase faster. In this paper, the potential...... of full duplex in providing fast discovery for the next 5th generation (5G) system supporting D2D communication is investigated. A design for such system is presented and evaluated via simulations, showing that full duplex can accelerate the discovery phase by supporting a higher transmission probability...

  20. Role of Duplex Doppler US for Thyroid Nodules: Looking for the 'Sword' Sign

    International Nuclear Information System (INIS)

    Lacout, Alexis; Marcy, Pierre Yves; Thariat, Juliette

    2011-01-01

    Duplex Doppler US may be useful for the detection of thyroid malignancies that show either anarchic winding or penetrating 'sword like' neoangiogenic vessels. It may be helpful in selecting nodules that should undergo fine needle aspiration biopsy.

  1. Phase transformations evaluation on a UNS S31803 duplex stainless steel based on nondestructive testing

    International Nuclear Information System (INIS)

    Macedo Silva, Edgard de; Costa de Albuquerque, Victor Hugo; Pereira Leite, Josinaldo; Gomes Varela, Antonio Carlos; Pinho de Moura, Elineudo; Tavares, Joao Manuel R.S.

    2009-01-01

    Duplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 deg. C, with the precipitation of the α' phase occurring over the ferritic microstructure. Aiming to characterise embrittlement of duplex stainless steel, hardening kinetics, from 425 to 475 deg. C, was analysed through the speed of sound, Charpy impact energy, X-ray diffraction, hardness and microscopy parameters. The presence of two hardening stages, detected through the speed of sound, was observed, one being of brittle characteristic and the other ductile. Moreover, the speed of sound showed a direct correlation with the material's hardness. Thus, it is concluded that the speed of sound is a promising nondestructive parameter to follow-up embrittlement in duplex stainless steel.

  2. Phase transformations evaluation on a UNS S31803 duplex stainless steel based on nondestructive testing

    Energy Technology Data Exchange (ETDEWEB)

    Macedo Silva, Edgard de, E-mail: edgard@cefetpb.edu.br [Centro federal de Educacao Tecnologica da Paraiba (CEFET PB), Area da Industria, Avenida 1o de Maio, 720 - 58015-430 - Joao Pessoa/PB (Brazil); Costa de Albuquerque, Victor Hugo, E-mail: victor.albuquerque@fe.up.pt [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Pereira Leite, Josinaldo, E-mail: josinaldo@ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Gomes Varela, Antonio Carlos, E-mail: varela@cefetpb.edu.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Pinho de Moura, Elineudo, E-mail: elineudo@pq.cnpq.br [Universidade Federal do Ceara (UFC), Departamento de Engenharia Metalurgica e de Materiais, Campus do Pici, Bloco 715, 60455-760 - Fortaleza/CE (Brazil); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.pt [Faculdade de Engenharia da Universidade do Porto (FEUP), Departamento de Engenharia Mecanica e Gestao Industrial (DEMEGI)/Instituto de Engenharia Mecanica e Gestao Industrial - INEGI, Rua Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal)

    2009-08-15

    Duplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 deg. C, with the precipitation of the {alpha}' phase occurring over the ferritic microstructure. Aiming to characterise embrittlement of duplex stainless steel, hardening kinetics, from 425 to 475 deg. C, was analysed through the speed of sound, Charpy impact energy, X-ray diffraction, hardness and microscopy parameters. The presence of two hardening stages, detected through the speed of sound, was observed, one being of brittle characteristic and the other ductile. Moreover, the speed of sound showed a direct correlation with the material's hardness. Thus, it is concluded that the speed of sound is a promising nondestructive parameter to follow-up embrittlement in duplex stainless steel.

  3. Full-Duplex Relaying with Improper Gaussian Signaling over Nakagami-m Fading Channels

    KAUST Repository

    Gaafar, Mohamed; Khafagy, Mohammad Galal; Amin, Osama; Schaefer, Rafael F.; Alouini, Mohamed-Slim

    2017-01-01

    We study the potential employment of improper Gaussian signaling (IGS) in full-duplex relaying (FDR) with non-negligible residual self-interference (RSI) under Nakagami- m fading. IGS is recently shown to outperform traditional proper Gaussian

  4. Underlay Spectrum Sharing Techniques with In-Band Full-Duplex Systems using Improper Gaussian Signaling

    KAUST Repository

    Gaafar, Mohamed; Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2016-01-01

    Sharing the spectrum with in-band full-duplex (FD) primary users (PUs) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-interference introduced at the primary network may dramatically impede

  5. Preoperative Duplex Scanning is a Helpful Diagnostic Tool in Neurogenic Thoracic Outlet Syndrome.

    Science.gov (United States)

    Orlando, Megan S; Likes, Kendall C; Mirza, Serene; Cao, Yue; Cohen, Anne; Lum, Ying Wei; Freischlag, Julie A

    2016-01-01

    To evaluate the diagnostic role of venous and arterial duplex scanning in neurogenic thoracic outlet syndrome (NTOS). Retrospective review of patients who underwent duplex ultrasonography prior to first rib resection and scalenectomy (FRRS) for NTOS from 2005 to 2013. Abnormal scans included ipsilateral compression (IC) with abduction of the symptomatic extremity (>50% change in subclavian vessel flow), contralateral (asymptomatic side) compression (CC) or bilateral compression (BC). A total of 143 patients (76% female, average age 34, range 13-59) underwent bilateral preoperative duplex scanning. Ipsilateral compression was seen in 44 (31%), CC in 12 (8%), and BC in 14 (10%). Seventy-three (51%) patients demonstrated no compression. Patients with IC more often experienced intraoperative pneumothoraces (49% vs. 25%, P duplex ultrasonography can assist in NTOS diagnosis. Ipsilateral compression on abduction often correlates with Adson testing. © The Author(s) 2016.

  6. Effects of trimethylamine N-oxide and urea on DNA duplex and G-quadruplex.

    Science.gov (United States)

    Ueda, Yu-Mi; Zouzumi, Yu-Ki; Maruyama, Atsushi; Nakano, Shu-Ichi; Sugimoto, Naoki; Miyoshi, Daisuke

    2016-01-01

    We systematically investigated effects of molecular crowding with trimethylamine N -oxide (TMAO) as a zwitterionic and protective osmolyte and urea as a nonionic denaturing osmolyte on conformation and thermodynamics of the canonical DNA duplex and the non-canonical DNA G-quadruplex. It was found that TMAO and urea stabilized and destabilized, respectively, the G-quadruplex. On the other hand, these osmolytes generally destabilize the duplex; however, it was observed that osmolytes having the trimethylamine group stabilized the duplex at the lower concentrations because of a direct binding to a groove of the duplex. These results are useful not only to predict DNA structures and their thermodynamics under physiological environments in living cells, but also design of polymers and materials to regulate structure and stability of DNA sequences.

  7. Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

    2016-05-01

    The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Influence of the filler material on the pitting corrosion in welded duplex stainless

    International Nuclear Information System (INIS)

    Munez, C. J.; Utrilla, M. V.; Urena, A.; Otero, E.

    2007-01-01

    In this work, it has been studied the pitting corrosion resistance of welding duplex stainless steel 2205. Unions were made by GMAW process with different fillers: duplex ER 2209 and two austenitic (ER 316LSi and ER 308LSi). the microstructure obtained with the duplex ER 2209 filler is similar to the duplex 2205 base material, but the unions produced with the austenitic fillers cause a decrease of the phases relationα/γ. To evaluate the influence of the filler on the weld, the pitting corrosion resistance was determined by electrochemical critical pitting temperature test (TCP) and the mechanical properties by the hardness. The phases imbalance produced for the dissimilar fillers bring out a variation of the pitting corrosion resistance and the mechanical properties. (Author)

  9. Contribution to the metallurgy of welding processes in stainless ferritic-austenitic (duplex) steels

    International Nuclear Information System (INIS)

    Perteneder, E.; Toesch, J.; Rabensteiner, G.

    1989-01-01

    Duplex steels have a ferritic austenitic structure. Therefore, to obtain a successful welding, special metallurgical regulations must be observed. The effect of energy per unit length and plate thickness onto the heat influence zone in case of manual arc welding is examined. Practice-oriented instructions for the welding technique to be applied are deduced from the results. Finally, the effect of the alloy composition onto the welding capacity of duplex steels is examined. (orig.) [de

  10. Aging behaviour of 25Cr-17Mn high nitrogen duplex stainless steel

    OpenAIRE

    Machado, I. F.; Padilha, A. F.

    2000-01-01

    The precipitation behaviour of a nickel free stainless steel containing 25% chromium, 17% manganese and 0.54% nitrogen, with duplex ferritic-austenitic microstructure, was studied using several complementary techniques of microstructural analysis after aging heat treatments between 600 and 1 000 degrees C for periods of lime between 15 and 6 000 min. During aging heat treatments, ferrite was decomposed into sigma phase and austenite by a eutectoid reaction, like in the Fe-Cr-Ni duplex stainle...

  11. Probing of miniPEGγ-PNA-DNA Hybrid Duplex Stability with AFM Force Spectroscopy.

    Science.gov (United States)

    Dutta, Samrat; Armitage, Bruce A; Lyubchenko, Yuri L

    2016-03-15

    Peptide nucleic acids (PNA) are synthetic polymers, the neutral peptide backbone of which provides elevated stability to PNA-PNA and PNA-DNA hybrid duplexes. It was demonstrated that incorporation of diethylene glycol (miniPEG) at the γ position of the peptide backbone increased the thermal stability of the hybrid duplexes (Sahu, B. et al. J. Org. Chem. 2011, 76, 5614-5627). Here, we applied atomic force microscopy (AFM) based single molecule force spectroscopy and dynamic force spectroscopy (DFS) to test the strength and stability of the hybrid 10 bp duplex. This hybrid duplex consisted of miniPEGγ-PNA and DNA of the same length (γ(MP)PNA-DNA), which we compared to a DNA duplex with a homologous sequence. AFM force spectroscopy data obtained at the same conditions showed that the γ(MP)PNA-DNA hybrid is more stable than the DNA counterpart, 65 ± 15 pN vs 47 ± 15 pN, respectively. The DFS measurements performed in a range of pulling speeds analyzed in the framework of the Bell-Evans approach yielded a dissociation constant, koff ≈ 0.030 ± 0.01 s⁻¹ for γ(MP)PNA-DNA hybrid duplex vs 0.375 ± 0.18 s⁻¹ for the DNA-DNA duplex suggesting that the hybrid duplex is much more stable. Correlating the high affinity of γ(MP)PNA-DNA to slow dissociation kinetics is consistent with prior bulk characterization by surface plasmon resonance. Given the growing interest in γ(MP)PNA as well as other synthetic DNA analogues, the use of single molecule experiments along with computational analysis of force spectroscopy data will provide direct characterization of various modifications as well as higher order structures such as triplexes and quadruplexes.

  12. Impact of Duplex arterial mapping on decision making in non-acute ischemic limb patients.

    Science.gov (United States)

    Elbadawy, A; Aly, H; Ibrahim, M; Bakr, H

    2015-12-01

    The aim of this study was to demonstrate the impact of Duplex arterial mapping on decision making in non-acute ischemic limb patient group reporting pain onset between 15 days and 3 months. We prospectively evaluated patients presented with critical limb ischemia who reported pain onset of duration between 15 days and 3 months in one-year period. Our series included thirty cases (mean age=61.3 years old), as Duplex arterial mapping was the sole preoperative imaging tool performed in all of them. All patients, in whom duplex indicated thrombosis in long occluded segments, were candidates for fluoroscopically guided thrombectomy. When Duplex defined chronic arterial occlusions, patients underwent endovascular or bypass revascularisation procedures. Impact of Duplex wall interrogation on decision-making between the two groups (subacute and chronic) was measured. Duplex arterial mapping categorized correctly all 30 patients into either subacute ischemia with removable clot (N.=14) or chronic ischemia (N.=16). Fluoroscopic guided thrombectomy was performed in 14 cases when Duplex advised long occluded arterial segments as indicted by intact intima with echogenic thrombus inside. Bypass surgery was performed in 8 patients. Percutaneous transluminal angioplasty (PTA) was done in 7 cases and thrombendartrectomy of common femoral artery in a single case. One-year patency rate in our series was 86.6%. It was 71.4% in thrombosis group. Limb salvage rate was 93.3%. Duplex arterial mapping could be used to differentiate the subacute ischemia with removable thrombus and chronic arterial occlusions guiding for the best revascularization procedure accordingly.

  13. Duplex recombinase polymerase amplification assays incorporating competitive internal controls for bacterial meningitis detection.

    Science.gov (United States)

    Higgins, Owen; Clancy, Eoin; Forrest, Matthew S; Piepenburg, Olaf; Cormican, Martin; Boo, Teck Wee; O'Sullivan, Nicola; McGuinness, Claire; Cafferty, Deirdre; Cunney, Robert; Smith, Terry J

    2018-04-01

    Recombinase polymerase amplification (RPA) is an isothermal nucleic acid amplification technology that provides rapid and robust infectious disease pathogen detection, ideal for point-of-care (POC) diagnostics in disease-prevalent low-resource countries. We have developed and evaluated three duplex RPA assays incorporating competitive internal controls for the detection of leading bacterial meningitis pathogens. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae singleplex RPA assays were initially developed and evaluated, demonstrating 100% specificity with limits of detection of 4.1, 8.5 and 3.9 genome copies per reaction, respectively. Each assay was further developed into internally controlled duplex RPA assays via the incorporation of internal amplification control templates. Clinical performance of each internally controlled duplex RPA assay was evaluated by testing 64 archived PCR-positive clinical samples. Compared to real-time PCR, all duplex RPA assays demonstrated 100% diagnostic specificity, with diagnostic sensitivities of 100%, 86.3% and 100% for the S. pneumoniae, N. meningitidis and H. influenzae assays, respectively. This study details the first report of internally controlled duplex RPA assays for the detection of bacterial meningitis pathogens: S. pneumoniae, N. meningitidis and H. influenzae. We have successfully demonstrated the clinical diagnostic utility of each duplex RPA assay, introducing effective diagnostic technology for POC bacterial meningitis identification in disease-prevalent developing countries. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Nanopore Analysis of the 5-Guanidinohydantoin to Iminoallantoin Isomerization in Duplex DNA.

    Science.gov (United States)

    Zeng, Tao; Fleming, Aaron M; Ding, Yun; Ren, Hang; White, Henry S; Burrows, Cynthia J

    2018-04-06

    In DNA, guanine oxidation yields diastereomers of 5-guanidinohydantoin (Gh) as one of the major products. In nucleosides and single-stranded DNA, Gh is in a pH-dependent equilibrium with its constitutional isomer iminoallantoin (Ia). Herein, the isomerization reaction between Gh and Ia was monitored in duplex DNA using a protein nanopore by measuring the ionic current when duplex DNA interacts with the pore under an electrophoretic force. Monitoring current levels in this single-molecule method proved to be superior for analysis of population distributions in an equilibrating mixture of four isomers in duplex DNA as a function of pH. The results identified Gh as a major isomer observed when base paired with A, C, or G at pH 6.4-8.4, and Ia was a minor isomer of the reaction mixture that was only observed when the pH was >7.4 in the duplex DNA context. The present results suggest that Gh will be the dominant isomer in duplex DNA under physiological conditions regardless of the base-pairing partner in the duplex.

  15. Quality assurance of lower limb venous duplex scans performed by vascular surgeons.

    Science.gov (United States)

    Kordowicz, A; Ferguson, G; Salaman, R; Onwudike, M

    2015-02-01

    Duplex scanning is the gold standard for investigating venous reflux; increasingly surgeons perform these scans themselves. There has been no data published analysing the accuracy of Duplex scans performed by vascular surgeons. We aimed to evaluate an objective method of comparing the results of lower limb Duplex scans performed by one consultant vascular surgeon with those performed by a vascular technologist. We assessed 100 legs with symptomatic varicose veins. Each patient underwent two lower limb venous Duplex scans; one performed by a consultant vascular surgeon and one by a vascular technologist. Scan results were randomised and sent to two consultant vascular surgeons blinded to the identity and experience of the sonographer. They were asked to recommend treatment. A k score was calculated in each case to assess the level of agreement between the scans performed by the consultant and the technologist. Eighty-one patients were studied (53 females). The kappa score for assessor 1 was 0.60 (95%CI:0.44-0.75) and for assessor 2 was 0.62 (95%CI:0.48-0.75). k scores >0.60 represent a substantial strength of agreement. Duplex scans performed by this surgeon were comparable to those performed by a vascular technologist. It is possible to quality-assure duplex performed by vascular surgeons without directly observing the scanning process or reviewing digitally recorded images. We propose standardisation of training, assessment and quality assurance for vascular surgeons wishing to perform ultrasound scans.

  16. Duplex-guided percutaneous transluminal angioplasty in iliac arterial occlusive disease.

    Science.gov (United States)

    Krasznai, A G; Sigterman, T A; Welten, R J; Heijboer, R; Sikkink, C J J M; van de Akker, L H J M; Bouwman, L H

    2013-11-01

    Chronic renal insufficiency (CRI) is a growing global problem. PTA can be performed without nephrotoxic contrast, utilizing Doppler-ultrasound (Duplex) guidance. Duplex-guided infra-inguinal interventions and access-related interventions have been reported. Duplex-guided iliac interventions have not been performed to any extent because of the anatomic location. In our study we evaluated the safety and efficacy of Duplex-guided percutaneous transluminal angioplasty (DuPTA) in iliac arteries. From June 2012 until February 2013, 31 patients (35 iliac lesions), underwent DuPTA. Indications ranged from Rutherford 3 to 5. Preoperative evaluation included Ankle Brachial Index (ABI), Duplex and MRA. Procedural success was defined as crossing the lesion with a guidewire and dilating or stenting the lesion. Clinical success was defined as 50% reduction in peak systolic velocity (PSV) or clinical improvement. PSV was evaluated after PTA, then at 2 weeks. Clinical results were assessed 2 weeks after the procedure. Procedural success was achieved in 94% of patients (33/35), all of whom also had clinical success. Post-procedural PSV reduction showed an average improvement of 63% (431 cm/s to 153 cm/s). Mean preoperative ABI was 0.72 and improved to 0.88 postoperatively. PTA using Duplex-guidance in significant iliac stenosis is a safe method with major advantages in patients at high risk for developing contrast-induced nephropathy. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  17. In-Band α-Duplex Scheme for Cellular Networks: A Stochastic Geometry Approach

    KAUST Repository

    Alammouri, Ahmad

    2016-07-13

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink interference. This paper presents a tractable framework, based on stochastic geometry, to study FD communications in cellular networks. Particularly, we assess the FD communications effect on the network performance and quantify the associated gains. The study proves the vulnerability of the uplink to the downlink interference and shows that FD rate gains harvested in the downlink (up to 97%) come at the expense of a significant degradation in the uplink rate (up to 94%). Therefore, we propose a novel fine-grained duplexing scheme, denoted as -duplex scheme, which allows a partial overlap between the uplink and the downlink frequency bands. We derive the required conditions to harvest rate gains from the -duplex scheme and show its superiority to both the FD and half-duplex (HD) schemes. In particular, we show that the -duplex scheme provides a simultaneous improvement of 28% for the downlink rate and 56% for the uplink rate. Finally, we show that the amount of the overlap can be optimized based on the network design objective.

  18. Ultrasensitive Detection of RNA and DNA Viruses Simultaneously Using Duplex UNDP-PCR Assay

    Science.gov (United States)

    Wang, Zengguo; Zhang, Xiujuan; Zhao, Xiaomin; Du, Qian; Chang, Lingling; Tong, Dewen

    2015-01-01

    Mixed infection of multiple viruses is common in modern intensive pig rearing. However, there are no methods available to detect DNA and RNA viruses in the same reaction system in preclinical level. In this study, we aimed to develop a duplex ultrasensitive nanoparticle DNA probe-based PCR assay (duplex UNDP-PCR) that was able to simultaneously detect DNA and RNA viruses in the same reaction system. PCV2 and TGEV are selected as representatives of the two different types of viruses. PCV2 DNA and TGEV RNA were simultaneously released from the serum sample by boiling with lysis buffer, then magnetic beads and gold nanoparticles coated with single and/or duplex specific probes for TGEV and PCV2 were added to form a sandwich-like complex with nucleic acids released from viruses. After magnetic separation, DNA barcodes specific for PCV2 and TGEV were eluted using DTT and characterized by specific PCR assay for specific DNA barcodes subsequently. The duplex UNDP-PCR showed similar sensitivity as that of single UNDP-PCR and was able to detect 20 copies each of PCV2 and TGEV in the serum, showing approximately 250-fold more sensitivity than conventional duplex PCR/RT-PCR assays. No cross-reaction was observed with other viruses. The positive detection rate of single MMPs- and duplex MMPs-based duplex UNDP-PCR was identical, with 29.6% for PCV2, 9.3% for TGEV and 3.7% for PCV2 and TGEV mixed infection. This duplex UNDP-PCR assay could detect TGEV (RNA virus) and PCV2 (DNA virus) from large-scale serum samples simultaneously without the need for DNA/RNA extraction, purification and reverse transcription of RNA, and showed a significantly increased positive detection rate for PCV2 (29%) and TGEV (11.7%) preclinical infection than conventional duplex PCR/RT-PCR. Therefore, the established duplex UNDP-PCR is a rapid and economical detection method, exhibiting high sensitivity, specificity and reproducibility. PMID:26544710

  19. Ultrasensitive Detection of RNA and DNA Viruses Simultaneously Using Duplex UNDP-PCR Assay.

    Directory of Open Access Journals (Sweden)

    Yong Huang

    Full Text Available Mixed infection of multiple viruses is common in modern intensive pig rearing. However, there are no methods available to detect DNA and RNA viruses in the same reaction system in preclinical level. In this study, we aimed to develop a duplex ultrasensitive nanoparticle DNA probe-based PCR assay (duplex UNDP-PCR that was able to simultaneously detect DNA and RNA viruses in the same reaction system. PCV2 and TGEV are selected as representatives of the two different types of viruses. PCV2 DNA and TGEV RNA were simultaneously released from the serum sample by boiling with lysis buffer, then magnetic beads and gold nanoparticles coated with single and/or duplex specific probes for TGEV and PCV2 were added to form a sandwich-like complex with nucleic acids released from viruses. After magnetic separation, DNA barcodes specific for PCV2 and TGEV were eluted using DTT and characterized by specific PCR assay for specific DNA barcodes subsequently. The duplex UNDP-PCR showed similar sensitivity as that of single UNDP-PCR and was able to detect 20 copies each of PCV2 and TGEV in the serum, showing approximately 250-fold more sensitivity than conventional duplex PCR/RT-PCR assays. No cross-reaction was observed with other viruses. The positive detection rate of single MMPs- and duplex MMPs-based duplex UNDP-PCR was identical, with 29.6% for PCV2, 9.3% for TGEV and 3.7% for PCV2 and TGEV mixed infection. This duplex UNDP-PCR assay could detect TGEV (RNA virus and PCV2 (DNA virus from large-scale serum samples simultaneously without the need for DNA/RNA extraction, purification and reverse transcription of RNA, and showed a significantly increased positive detection rate for PCV2 (29% and TGEV (11.7% preclinical infection than conventional duplex PCR/RT-PCR. Therefore, the established duplex UNDP-PCR is a rapid and economical detection method, exhibiting high sensitivity, specificity and reproducibility.

  20. Ultrasensitive Detection of RNA and DNA Viruses Simultaneously Using Duplex UNDP-PCR Assay.

    Science.gov (United States)

    Huang, Yong; Xing, Na; Wang, Zengguo; Zhang, Xiujuan; Zhao, Xiaomin; Du, Qian; Chang, Lingling; Tong, Dewen

    2015-01-01

    Mixed infection of multiple viruses is common in modern intensive pig rearing. However, there are no methods available to detect DNA and RNA viruses in the same reaction system in preclinical level. In this study, we aimed to develop a duplex ultrasensitive nanoparticle DNA probe-based PCR assay (duplex UNDP-PCR) that was able to simultaneously detect DNA and RNA viruses in the same reaction system. PCV2 and TGEV are selected as representatives of the two different types of viruses. PCV2 DNA and TGEV RNA were simultaneously released from the serum sample by boiling with lysis buffer, then magnetic beads and gold nanoparticles coated with single and/or duplex specific probes for TGEV and PCV2 were added to form a sandwich-like complex with nucleic acids released from viruses. After magnetic separation, DNA barcodes specific for PCV2 and TGEV were eluted using DTT and characterized by specific PCR assay for specific DNA barcodes subsequently. The duplex UNDP-PCR showed similar sensitivity as that of single UNDP-PCR and was able to detect 20 copies each of PCV2 and TGEV in the serum, showing approximately 250-fold more sensitivity than conventional duplex PCR/RT-PCR assays. No cross-reaction was observed with other viruses. The positive detection rate of single MMPs- and duplex MMPs-based duplex UNDP-PCR was identical, with 29.6% for PCV2, 9.3% for TGEV and 3.7% for PCV2 and TGEV mixed infection. This duplex UNDP-PCR assay could detect TGEV (RNA virus) and PCV2 (DNA virus) from large-scale serum samples simultaneously without the need for DNA/RNA extraction, purification and reverse transcription of RNA, and showed a significantly increased positive detection rate for PCV2 (29%) and TGEV (11.7%) preclinical infection than conventional duplex PCR/RT-PCR. Therefore, the established duplex UNDP-PCR is a rapid and economical detection method, exhibiting high sensitivity, specificity and reproducibility.

  1. Potential of duplex fuel in prebreeder, breeder, and power reactor designs: tests and analyses (AWBA Development Program)

    International Nuclear Information System (INIS)

    Chao, T.L.; Brennan, J.J.; Duncombe, E.; Schneider, M.J.; Johnson, R.G.R.

    1982-09-01

    Dual region fuel pellets, called duplex pellets, are comprised of an outer annular region of relatively high uranium fuel enrichment and a center pellet of fertile material with no enrichment. UO 2 and ThO 2 are the fissile and fertile materials of interest. Both prebreeders and breeders are discussed as are the performance advantages of duplex pellets over solid pellets in these two pressurized water reactor types. Advantages of duplex pellets for commercial reactor fuel rods are also discussed. Both irradiation test data and analytical results are used in comparisons. Manufacturing of duplex fuel is discussed

  2. Inclusion of methoxy groups inverts the thermodynamic stabilities of DNA-RNA hybrid duplexes: A molecular dynamics simulation study.

    Science.gov (United States)

    Suresh, Gorle; Priyakumar, U Deva

    2015-09-01

    Modified nucleic acids have found profound applications in nucleic acid based technologies such as antisense and antiviral therapies. Previous studies on chemically modified nucleic acids have suggested that modifications incorporated in furanose sugar especially at 2'-position attribute special properties to nucleic acids when compared to other modifications. 2'-O-methyl modification to deoxyribose sugars of DNA-RNA hybrids is one such modification that increases nucleic acid stability and has become an attractive class of compounds for potential antisense applications. It has been reported that modification of DNA strands with 2'-O-methyl group reverses the thermodynamic stability of DNA-RNA hybrid duplexes. Molecular dynamics simulations have been performed on two hybrid duplexes (DR and RD) which differ from each other and 2'-O-methyl modified counterparts to investigate the effect of 2'-O-methyl modification on their duplex stability. The results obtained suggest that the modification drives the conformations of both the hybrid duplexes towards A-RNA like conformation. The modified hybrid duplexes exhibit significantly contrasting dynamics and hydration patterns compared to respective parent duplexes. In line with the experimental results, the relative binding free energies suggest that the introduced modifications stabilize the less stable DR hybrid, but destabilize the more stable RD duplex. Binding free energy calculations suggest that the increased hydrophobicity is primarily responsible for the reversal of thermodynamic stability of hybrid duplexes. Free energy component analysis further provides insights into the stability of modified duplexes. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Hepatic venous pressure gradients measured by duplex ultrasound

    International Nuclear Information System (INIS)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M.

    2002-01-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P -2 provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  4. Eddy current techniques for super duplex stainless steel characterization

    International Nuclear Information System (INIS)

    Camerini, C.; Sacramento, R.; Areiza, M.C.; Rocha, A.; Santos, R.; Rebello, J.M.; Pereira, G.

    2015-01-01

    Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content. - Highlights: • Sigma phase precipitation, even for low amounts, dramatically affects SDSS properties. • SDSS samples were thermally treated and carefully characterized by X-Ray Diffraction. • NDT techniques detected low amounts of sigma phase in SDSS microstructure

  5. The mechanical features of isothermally annealed duplex stainless steel

    International Nuclear Information System (INIS)

    Sustarsic, B.; Godec, M.; Jenko, M.; Tuma, J.V.; Marini, B.; Toffolon Masclet, C.; Forget, P.

    2011-01-01

    Cast duplex stainless steels are frequently used for structural parts of nuclear power plants and other thermo-energetic objects. The ageing behaviour of the cast 258 type stainless steel has been studied in the frame of IMT Slovenia and CEA bilateral cooperation. The results of testing of French and Sloven partners are compared and analysed. The steel samples have been isothermally annealed for 10.000 and 30.000 hours at 300 and 350 C. ICP-AES bulk chemical analysis of samples, microstructure investigations with light (LM) and scanning electron microscope (SEM), micro-chemical analysis with SEM/EDS, as well as SEM/EBSD phase analyses have been performed. Tensile test specimens have been made from the aged samples and standard tensile test at room temperature was performed. The SEM fractography of fractured surfaces was also performed. Microhardness measurements of ferrite and austenite phase were determined on polished metallographic samples. The results of mechanical testing and fractographic examinations are reported and discussed in this paper. Microhardness of ferrite is drastically increased with time and temperature of ageing due to spinodal decomposition. But, hardness of austenite remains practically unchanged. Tensile properties changed, similarly. Yield point and tensile strength increased but ductility significantly decreased. In accordance with ductility decrease the nature of fractured surface changed from typical ductile to brittle and dimpled to cleavage, respectively. (authors)

  6. Diagnosing erectile dysfunction: the penile dynamic colour duplex ultrasound revisited.

    Science.gov (United States)

    Aversa, A; Bruzziches, R; Spera, G

    2005-12-01

    A number of disease processes of the penis including Peyronie's disease, priapism, penile fractures and tumors are clearly visualized with ultrasound. Diagnostic evaluation of erectile dysfunction (ED) by penile dynamic colour-duplex Doppler ultrasonography (D-CDDU) is actually considered a second level approach to ED patients because of the fact that intracavernous injections test IV with prostaglandin-E(1) may provide important information about the patients' erectile capacity. However, no direct vascular imaging and a high percentage of false negative diagnoses of vasculogenic ED are its major pitfalls and subsequent treatment decisions remain quite limited. The occurrence of ED and its sentinel relationship to cardiovascular disease has prompted more accurate vascular screening in all patients even in the absence of cardiovascular risk factors. The sonographic evaluation of the intima-media thickness of the carotid arteries may sometimes represent an early manifestation of diffuse atherosclerotic disease and endothelial damage. This latter finding is often the cause of failure to oral agents, i.e. phosphodiesterase inhibitors, because of inability of the dysfunctional endothelium to release nitric oxide. D-CDDU represents an accurate tool to investigate cavernous artery inflow and venous leakage when compared with more invasive diagnostic techniques i.e. selective arteriography and dynamic infusion cavernosometry along with cavernosography.

  7. Aging of cast duplex stainless steels in LWR systems

    International Nuclear Information System (INIS)

    Chopra, O.K.; Chung, H.M.

    1984-10-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are evaluated to determine the expected embrittlement of cast components during the operating lifetime of reactors and to define the objectives and scope of the investigation. This presentation describes the status of the program. Data for the metallurgical characterization of the various cast stainless steels used in the investigation are presented. Charpy impact tests on short-term aged material indicate that CF-3 stainless steels are less susceptible to embrittlement than CF-8 or CF-8M stainless steels. Microstructural characterization of cast stainless steels that were obtained from Georg Fischer Co. and aged for up to 70,000 h at 300, 350, and 400 0 C reveals the formation of four different types of precipitates that are not α'. Embrittlement of the ferrite phase is primarily due to pinning of the dislocations by two of these precipitates, designated as Type M and Type X. The ferrite phase is embrittled after approx. 8 y at 300 0 C and shows cleavage fracture. Examination of the fracture surfaces of the impact-test specimens indicates that the toughness of the long-term aged material is determined by the austenite phase. 8 figures, 3 tables

  8. Kinetics of sigma phase formation in a Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Rodrigo Magnabosco

    2009-09-01

    Full Text Available This work determines the kinetics of sigma phase formation in UNS S31803 Duplex Stainless Steel (DSS, describing the phase transformations that occur in isothermal aging between 700 and 900 ºC for time periods up to 1032 hours, allowing the determination of the Time-Temperature-Precipitation (TTP diagram for sigma phase and proposing a model to predict the kinetics of sigma phase formation using a Johnson-Mehl-Avrami (JMA type expression. The higher kinetics of sigma phase formation occurs at 850 ºC. However, isothermal aging between 700 and 900 ºC for time periods up to 1032 hours are not sufficient to the establishment of thermodynamic equilibrium. Activation energy for both nucleation and growth of sigma phase is determined (185 kJ.mol-1 and its value is equivalent to the activation energy for Cr diffusion in ferrite, indicating that diffusion of Cr is probably the major thermally activated process involved in sigma phase formation. The determined JMA type expression presents good fit with experimental data between 700 and 850 ºC.

  9. Eddy current techniques for super duplex stainless steel characterization

    Energy Technology Data Exchange (ETDEWEB)

    Camerini, C., E-mail: cgcamerini@metalmat.ufrj.br [Laboratory of Non-Destructive Testing, Corrosion and Welding, Department of Metallurgical and Materials Engineering, Federal University of Rio de Janeiro (Brazil); Sacramento, R.; Areiza, M.C.; Rocha, A. [Laboratory of Non-Destructive Testing, Corrosion and Welding, Department of Metallurgical and Materials Engineering, Federal University of Rio de Janeiro (Brazil); Santos, R. [PETROBRAS R& D Center, Rio de Janeiro (Brazil); Rebello, J.M.; Pereira, G. [Laboratory of Non-Destructive Testing, Corrosion and Welding, Department of Metallurgical and Materials Engineering, Federal University of Rio de Janeiro (Brazil)

    2015-08-15

    Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content. - Highlights: • Sigma phase precipitation, even for low amounts, dramatically affects SDSS properties. • SDSS samples were thermally treated and carefully characterized by X-Ray Diffraction. • NDT techniques detected low amounts of sigma phase in SDSS microstructure.

  10. Superplastic boronizing of duplex stainless steel under dual compression method

    International Nuclear Information System (INIS)

    Jauhari, I.; Yusof, H.A.M.; Saidan, R.

    2011-01-01

    Highlights: → Superplastic boronizing. → Dual compression method has been developed. → Hard boride layer. → Bulk deformation was significantly thicker the boronized layer. → New data on boronizing could be expanded the application of DSS in industries. - Abstract: In this work, SPB of duplex stainless steel (DSS) under compression method is studied with the objective to produce ultra hard and thick boronized layer using minimal amount of boron powder and at a much faster boronizing time as compared to the conventional process. SPB is conducted under dual compression methods. In the first method DSS is boronized using a minimal amount of boron powder under a fix pre-strained compression condition throughout the process. The compression strain is controlled in such a way that plastic deformation is restricted at the surface asperities of the substrate in contact with the boron powder. In the second method, the boronized specimen taken from the first mode is compressed superplastically up to a certain compressive strain under a certain strain rate condition. The process in the second method is conducted without the present of boron powder. As compared with the conventional boronizing process, through this SPB under dual compression methods, a much harder and thicker boronized layer thickness is able to be produced using a minimal amount of boron powder.

  11. Fatigue damage in coarse-grained lean duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Strubbia, R., E-mail: strubbia@ifir-conicet.gov.ar; Hereñú, S.; Marinelli, M.C.; Alvarez-Armas, I.

    2016-04-06

    The present investigation is focused on assessing the effect of a thermal treatment for grain coarsening on the low cycle fatigue damage evolution in two types of Lean Duplex Stainless Steels (LDSSs). The dislocation structure developed during cycling is observed by transmission electron microscopy (TEM). Additionally, a detailed analysis of short crack initiated and grown during low cycle fatigue (LCF) is performed by means of optical and scanning electron (SEM) microscopy in combination with automated electron back-scattered diffraction (EBSD) technique. Though in both coarse-grained LDSSs the short cracks nucleate in the ferrite phase, in each steels its origin is different. The embrittlement caused by the Cr{sub 2}N precipitation and the plastic activity sustained by each phase can explain this difference. The propagation behavior of the short cracks present two alternative growing mechanisms: the crack grows along a favorable slip plane with high Schmid Factor (SF) or the crack alternates between two slip systems. In both cases, the crack follows the path with the smallest tilt angle (β) at a grain boundary.

  12. Superplastic boronizing of duplex stainless steel under dual compression method

    Energy Technology Data Exchange (ETDEWEB)

    Jauhari, I., E-mail: iswadi@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Yusof, H.A.M.; Saidan, R. [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-10-25

    Highlights: {yields} Superplastic boronizing. {yields} Dual compression method has been developed. {yields} Hard boride layer. {yields} Bulk deformation was significantly thicker the boronized layer. {yields} New data on boronizing could be expanded the application of DSS in industries. - Abstract: In this work, SPB of duplex stainless steel (DSS) under compression method is studied with the objective to produce ultra hard and thick boronized layer using minimal amount of boron powder and at a much faster boronizing time as compared to the conventional process. SPB is conducted under dual compression methods. In the first method DSS is boronized using a minimal amount of boron powder under a fix pre-strained compression condition throughout the process. The compression strain is controlled in such a way that plastic deformation is restricted at the surface asperities of the substrate in contact with the boron powder. In the second method, the boronized specimen taken from the first mode is compressed superplastically up to a certain compressive strain under a certain strain rate condition. The process in the second method is conducted without the present of boron powder. As compared with the conventional boronizing process, through this SPB under dual compression methods, a much harder and thicker boronized layer thickness is able to be produced using a minimal amount of boron powder.

  13. Quantification of cerebral blood flow via Duplex sonography

    International Nuclear Information System (INIS)

    Vogl, G.; Pohl, P.; Willeit, J.; Aichner, F.

    1987-01-01

    An attempt was made to measure quantitatively the total cerebral blood flow by means of Duplex sonography. In a group of healthy young subjects a median value for total cerebral blood flow was obtained amounting to 469 ml/min ± 30%, repeat measurements yielded a maximum deviation of ± 11%. In three patients the values obtained after severe apoplectic insult due to occlusion of the internal carotid artery were definitely below the value of the group of healthy subjects, whereas the value for the total blood flow was in the upper range of normal values in a patient with occlusion of the a. cerebri media. Comparative measurements of the regional cerebral blood flow with xenon 13 yielded in those patients with occlusion of the internal carotid artery a markedly reduced mean flow and in the patient with occlusion of the a. cerebri media a less markedly reduced mean flow. Regionally reduced perfusion was seen in all the four patients in the range of the clinically and computer tomographically well-known ischaemia zone. Thanks to the simplicity of this sonographic examination method it could be a useful decision parameter in determining the indication for a reconstruction of the carotid artery, especially in asymptotic patients. (orig.) [de

  14. Screen for intracranial dural arteriovenous fistulae with carotid duplex sonography.

    Science.gov (United States)

    Tsai, L-K; Yeh, S-J; Chen, Y-C; Liu, H-M; Jeng, J-S

    2009-11-01

    Early diagnosis and management of intracranial dural arteriovenous fistulae (DAVF) may prevent the occurrence of stroke. This study aimed to identify the best carotid duplex sonography (CDS) parameters for screening DAVF. 63 DAVF patients and 170 non-DAVF patients received both CDS and conventional angiography. The use of seven CDS haemodynamic parameter sets related to the resistance index (RI) of the external carotid artery (ECA) for the diagnosis of DAVF was validated and the applicability of the best CDS parameter set in 20 400 patients was tested. The CDS parameter set (ECA RI (cut-off point = 0.7) and internal carotid artery (ICA) to ECA RI ratio (cut-off point = 0.9)) had the highest specificity (99%) for diagnosis of DAVF with moderate sensitivity (51%). Location of the DAVF was a significant determinant of sensitivity of detection, which was 70% for non-cavernous DAVF and 0% for cavernous sinus DAVF (pdetected abnormality in 92 of 20 400 patients. These abnormalities included DAVF (n = 25), carotid stenosis (n = 32), vertebral artery stenosis (n = 7), intracranial arterial stenosis (n = 6), head and neck tumour (n = 3) and unknown aetiology (n = 19). Combined CDS parameters of ECA RI and ICA to ECA RI ratio can be used as a screening tool for the diagnosis of DAVF.

  15. Ageing and life prediction of cast duplex stainless steel components

    International Nuclear Information System (INIS)

    Chung, H.M.

    1992-01-01

    Cast duplex stainless steels, used extensively in nuclear, chemical and petroleum industries because of higher strength, better weldability, higher resistance to stress corrosion cracking, and soundness of casting, are susceptible to thermal aging embrittlement during service at temperatures as low as ∼250 o C. Recent advances in understanding the aging mechanisms, kinetics, and mechanical properties are presented, with emphasis on application of the material in safety-significant components in a nuclear reactor. Aging embrittlement is primarily due to spinodal decomposition of ferrite involving segregation of Fe, Cr, and Ni, and precipitation of M 23 C 6 on ferrite-austenite boundaries or in ferrite. Aging kinetics are strongly influenced by synergistic effects of other metallurgical reactions that occur in parallel with the spinodal decomposition, i.e. clustering of Ni, Mo, and Si and G-phase precipitation in ferrite. A number of methods are outlined for estimating end-of-life aging, depending on several factors such as degree of permissible conservatism, availability of component archive material, and methods of estimating and verifying the activation energy of aging. (Author)

  16. Modern high strength QT, TM and duplex-stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Bocquet, P. [Industeel (France); Luxenburger, G. [Aktiengesellschaft der Dillinger Huettenwerke, Dillingen/Saar (Germany); Porter, D. [Rautaruukki (Finland); Ericsson, C. [Avesta Polarit (Sweden)

    2003-07-01

    Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

  17. Hardfacing of duplex stainless steel using melting and diffusion processes

    Science.gov (United States)

    Lailatul, H.; Maleque, M. A.

    2017-03-01

    Duplex stainless steel (DSS) is a material with high potential successes in many new applications such as rail car manufacturing, automotive and chemical industries. Although DSS is widely used in various industries, this material has faced wear and hardness problems which obstruct a wider capability of this material and causes problems in current application. Therefore, development of surface modification has been introduced to produce hard protective layer or coating on DSS. The main aim of this work is to brief review on hard surface layer formation on DSS using melting and diffusion processes. Melting technique using tungsten inert gas (TIG) torch and diffusion technique using gas nitriding are the effective process to meet this requirement. The processing route plays a significant role in developing the hard surface layer for any application with effective cost and environmental factors. The good understanding and careful selection of processing route to form products are very important factors to decide the suitable techniques for surface engineering treatment. In this paper, an attempt is also made to consolidate the important research works done on melting and diffusion techniques of DSS in the past. The advantages and disadvantages between melting and diffusion technique are presented for better understanding on the feasibility of hard surface formation on DSS. Finally, it can be concluded that this work will open an avenue for further research on the application of suitable process for hard surface formation on DSS.

  18. Plasma immersion ion implantation: duplex layers from a single process

    International Nuclear Information System (INIS)

    Hutchings, R.; Collins, G.A.; Tendys, J.

    1992-01-01

    Plasma immersion ion implantation (PI 3 ) is an alternative non-line-of-sight technique for implanting ions directly from a plasma which surrounds the component to be treated. In contrast to plasma source ion implantation, the PI 3 system uses an inductively coupled r.f. plasma. It is shown that nitrogen can be retained during implantation at elevated temperatures, even for unalloyed steels. This allows controlled diffusion of nitrogen to greater depths, thereby improving the load bearing capacity of the implanted layer. Components can be heated directly, using the energy deposited by the incident ions during the pulsed implantation. The necessary temperature control can be accomplished simply by regulating the frequency and length of the high voltage pulses applied to the component. Chemical depth profiles and microstructural data obtained from H13 tool steel are used to show that PI 3 can, in a single process, effectively produce a duplex subsurface structure. This structure consists of an outer non-equilibrium layer typical of nitrogen implantation (containing in excess of 20 at.% nitrogen) backed by a substantial diffusion zone of much lower nitrogen content. The relationship between implantation temperature and the resultant subsurface microstructure is explored. (orig.)

  19. Hepatic venous pressure gradients measured by duplex ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M

    2002-08-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P < 0.0001) and with the Child-Pugh score (r = 0.63, P < 0.0001). An acceleration index cut-off value of 1 m.s{sup -2} provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  20. Behavior of duplex stainless steel casting defects under mechanical loadings

    Energy Technology Data Exchange (ETDEWEB)

    Jayet-Gendrot, S [Electricite de France, 77 - Moret-sur-Loing (France). Dept. of Materials Study; Gilles, P; Migne, C [Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Paris-La-Defense (France)

    1997-04-01

    Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster`s envelope. The tests are analyzed in order to develop a method that takes into account the behavior of castings defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modelling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (author) 18 refs.

  1. Eddy current techniques for super duplex stainless steel characterization

    Science.gov (United States)

    Camerini, C.; Sacramento, R.; Areiza, M. C.; Rocha, A.; Santos, R.; Rebello, J. M.; Pereira, G.

    2015-08-01

    Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content.

  2. Superplastic Forming of Duplex Stainless Steel for Aerospace Part

    Science.gov (United States)

    Lee, Ho-Sung; Yoon, Jong-Hoon; Yoo, Joon-Tae; Yi, Young-Moo

    2011-08-01

    In this study, the high temperature forming behavior of duplex stainless steel has been characterized and the outer shell of a combustion chamber was fabricated with pressure difference of hot gas. It consists of two parts which are the outer skin made of stainless steel to sustain the internal pressure and the inner shell made of copper alloy for regenerative cooling channels. Two outer skins partitioned to half with respect to the symmetric axis was prepared by hot gas forming process with a maximum pressure of 7 MPa following to FEM analysis. For inner layer, copper alloy was machined for cooling channels and then placed in the gas pressure welding fixture. It is shown that the optimum condition of gas pressure welding is 7 MPa at 890 °C, for one hour. EDX analysis and scanning electron microscope micrograph confirm the atomic diffusion process is observed at the interface and copper atoms diffuse into steel, while iron and chrome atoms diffuse into copper. The result shows that the manufacturing method with superplastic forming and gas pressure welding of steel and copper alloy has been successful for near net shape manufacturing of scaled combustion chamber of launch vehicle.

  3. Fracture toughness of a welded super duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pilhagen, Johan, E-mail: pilhagen@kth.se [Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden); Sieurin, Henrik [Scania CV AB, Södertälje (Sweden); Sandström, Rolf [Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden)

    2014-06-01

    Fracture toughness testing was conducted on standard single-edge notched bend bar specimens of base and weld metal. The material was the SAF 2906 super duplex stainless steel. The aim was to evaluate the susceptibility for brittle failure at sub-zero temperatures for the base and weld metal. The base metal was tested between −103 and −60 °C and was evaluated according to the crack-tip opening displacement method. The fracture event at and below −80 °C can be described as ductile until critical cleavage initiation occurs, which caused unstable failure of the specimen. The welding method used was submerged arc welding with a 7 wt% nickel filler metal. The welded specimens were post-weld heat treated (PWHT) at 1100 °C for 20 min and then quenched. Energy-dispersive X-ray spectroscopy analysis showed that during PWHT substitutional element partitioning occurred which resulted in decreased nickel content in the ferrite. The PWHT weld metal specimens were tested at −72 °C. The fracture sequence was critical cleavage fracture initiation after minor crack-tip blunting and ductile fracture.

  4. Precipitation Mechanism of Sigma Phase in Super Duplex Stainless Steels

    Science.gov (United States)

    Nakade, Katsuyuki; Kuroda, Toshio

    The influence of alloying elements on the precipitation behavior of sigma (σ) phase was investigated for conventional SAF2205 and SAF2507 super duplex stainless steel. Time-Temperature-Precipitation (T-T-P) diagram of sigma phase of SAF2507 were shifted toward to shorter times compared to SAF2205. The precipitation of sigma phase was accelerated with increasing Cr and Mo concentration. According to the microstructure observation, the sigma phase began to precipitate at ferrite (α) ⁄ austenite (γ) phase boundaries and grew into ferrite for SAF2507 and SAF2205 steel. In the as-received condition, Cr and Mo concentration in ferrite was clearly higher than that in austenite. Especially, it was found that Mo concentration in ferrite of SAF2507 was higher than that in ferrite of SAF2205. The result of EPMA-measurement showed that sigma phase was mainly Fe-Cr-Mo intermetallic compound and Mo was significantly enriched into sigma phase. The difference of Mo concentration in ferrite significantly affected to the sigma phase precipitation. The secondary austenite formation was also induced by sigma phase precipitation. Cr and Mo were ejected to the remained ferrite ⁄ austenite phase boundaries by secondary austenite formation. Consequently, sigma phase precipitation was more accelerated by the reheating.

  5. Circularly polarized luminescence of helically assembled pyrene π-stacks on RNA and DNA duplexes.

    Science.gov (United States)

    Nakamura, Mitsunobu; Ota, Fuyuki; Takada, Tadao; Akagi, Kazuo; Yamana, Kazushige

    2018-05-01

    In this report, we describe the circularly polarized luminescence (CPL) of the RNA duplexes having one to four 2'-O-pyrene modified uridines (Upy) and the DNA duplexes having two, four, and six pyrene modified non-nucleosidic linkers (Py). Both the pyrene π-stack arrays formed on the RNA and DNA double helical structures exhibited pyrene excimer fluorescence. In the pyrene-modified RNA systems, the RNA duplex having four Upys gives CPL emission with g lum value of <0.01 at 480 nm. The structure of pyrene stacks on the RNA duplex may be rigidly regulated with increase in the Upy domains, which resulted in the CPL emission. In the DNA systems, the pyrene-modified duplexes containing two and four Pys exhibited CPL emission with g lum values of <0.001 at 505 nm. The pyrene π-stack arrays presented here show CPL emission. However, the g lum values are relatively small when compared with our previous system consisting of the pyrene-zipper arrays on RNA. © 2018 Wiley Periodicals, Inc.

  6. A Full-Duplex MAC Tailored for 5G Wireless Networks

    Directory of Open Access Journals (Sweden)

    Lucas de Melo Guimarães

    2018-01-01

    Full Text Available The increasing demands for high-data rate traffic stimulated the development of the fifth-generation (5G mobile networks. The envisioned 5G network is expected to meet its challenge by devising means to further improve spectrum usage. Many alternatives to enhance spectrum usage are being researched, such as massive MIMO, operation in mmWave frequency, cognitive radio, and the employment of full-duplex antennas. Efficient utilization of the potential of any of these technologies faces a set of challenges related to medium access control (MAC schemes. This work focuses on MAC schemes tailored for full-duplex antennas, since they are expected to play a major role in the foreseeable 5G networks. In this context, this paper presents a MAC layer technique to improve total transmission time when full-duplex antennas are employed. Several evaluations in different scenarios are conducted to assess the proposed MAC scheme. Numerical results show that the proposed scheme provides gains up to 156% when compared to a state-of-the-art full-duplex antenna MAC protocol. Compared to traditional half-duplex antenna MAC protocols, the proposed scheme yields gain up to 412%.

  7. Microstructure and Antiwear Property of Laser Cladding Ni-Co Duplex Coating on Copper.

    Science.gov (United States)

    Wang, Yiyong; Liang, Zhipeng; Zhang, Junwei; Ning, Zhe; Jin, Hui

    2016-07-28

    Ni-Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al₂O₃/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni-Co duplex coatings comprised a Co-based solid solution, Cr₇C₃, (Fe,Ni) 23 C₆, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV). The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni-Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni-Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties.

  8. Microstructure and Antiwear Property of Laser Cladding Ni–Co Duplex Coating on Copper

    Science.gov (United States)

    Wang, Yiyong; Liang, Zhipeng; Zhang, Junwei; Ning, Zhe; Jin, Hui

    2016-01-01

    Ni–Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al2O3/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni–Co duplex coatings comprised a Co-based solid solution, Cr7C3, (Fe,Ni)23C6, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV). The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni–Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni–Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties. PMID:28773755

  9. Microstructure and Antiwear Property of Laser Cladding Ni–Co Duplex Coating on Copper

    Directory of Open Access Journals (Sweden)

    Yiyong Wang

    2016-07-01

    Full Text Available Ni–Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al2O3/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni–Co duplex coatings comprised a Co-based solid solution, Cr7C3, (Fe,Ni23C6, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV. The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni–Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni–Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties.

  10. Effects of chitosan inhibitor on the electrochemical corrosion behavior of 2205 duplex stainless steel

    Science.gov (United States)

    Yang, Se-fei; Wen, Ying; Yi, Pan; Xiao, Kui; Dong, Chao-fang

    2017-11-01

    The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency (IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl3 solution.

  11. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik

    2013-09-01

    Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

  12. Interactions Between Fibroblast Cells and Laser Beam Welded AISI 2205 Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ceyhun KÖSE

    2018-05-01

    Full Text Available Because of their high mechanical strength, excellent corrosion resistance and good weldability, duplex stainless steels are mostly used in industries such as oil, chemistry, petrochemistry, food and occasionally used in medical industry. These properties have enabled us to use duplex stainless steels in biomedical applications recently. Accordingly, duplex stainless steel material can be highly important to examine the toxic effect on the cells. In this study, the effect of the AISI 2205 duplex stainless steels which are joined by CO2 laser beam welding on viability of L929 fibroblast cells has been studied in vitro for the first time. For this aim, the cells were kept in DMEM/F-12 (Thermofisher Scientific 31331-028 medium for 7 days. The viability study was experimentally studied using the MTT (Thiazolyl Blue Tetrazolium Bromide method for 7 days. The cell viability of the laser beam welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. According to the obtained results, it was revealed that laser beam welded and base metal AISI 2205 duplex stainless steel has been found suitable to study for biomedical applications. DOI: http://dx.doi.org/10.5755/j01.ms.24.2.18006

  13. A morphological evaluation of a duplex stainless steel processed by high energy Ball Mill

    International Nuclear Information System (INIS)

    Yonekubo, Ariane Emi; Cintho, Osvaldo Mitsuyuki; Aguiar, Denilson Jose Marcolino de; Capocchi, Jose Deodoro Trani

    2009-01-01

    The duplex stainless steels are formed by a ferrite and austenite mixture, giving them a combination of properties. Commercially, these steels are hot rolled, developing an anisotropic, alternated ferrite and austenite elongated lamellae microstructure. In this work, a duplex stainless steel was produced by the mixture of elementary powders with the composition Fe-19.5Cr-5Ni processed in an ATTRITOR ball mill during periods up to 15 hours. The powders obtained were compressed in specimens and were heat treated in the temperatures of 900, 1050 and 1200 °C during 1 hour and analysed by x ray diffraction, optic microscopy, scanning electron microscopy and energy dispersion spectroscopy. An optimized microstructure with ultrafine, equiaxial and regular duplex microstructure was obtained in the 15 hour milling and 1200 °C heat treatment. Afterwards, a commercially super duplex stainless steel UNS S32520 was aged at 800 °C aiming the precipitation of σ phase in order to reduce its toughness and then, milled in SPEX mill. The resulting microstructure was a very fine duplex type with irregular grain boundary morphology duo to the grain growth barrier promoted by the renascent σ phase particles during sintering process. (author)

  14. Effect of Cavity Size of Mesoporous Silica on Short DNA Duplex Stability.

    Science.gov (United States)

    Masuda, Tsubasa; Shibuya, Yuuta; Arai, Shota; Kobayashi, Sayaka; Suzuki, Sotaro; Kijima, Jun; Itoh, Tetsuji; Sato, Yusuke; Nishizawa, Seiichi; Yamaguchi, Akira

    2018-05-15

    We studied the stabilities of short (4- and 3-bp) DNA duplexes within silica mesopores modified with a positively charged trimethyl aminopropyl (TMAP) monolayer (BJH pore diameter 1.6-7.4 nm). The DNA fragments with fluorescent dye were introduced into the pores, and their fluorescence resonance energy transfer (FRET) response was measured to estimate the structuring energies of the short DNA duplexes under cryogenic conditions (temperature 233-323 K). The results confirmed the enthalpic stability gain of the duplex within size-matched pores (1.6 and 2.3 nm). The hybridization equilibrium constants found for the size-matched pores were 2 orders of magnitude larger than those for large pores (≥3.5 nm), and this size-matching effect for the enhanced duplex stability was explained by a tight electrostatic interaction between the duplex and the surface TMAP groups. These results indicate the requirement of the precise regulation of mesopore size to ensure the stabilization of hydrogen-bonded supramolecular assemblies.

  15. Duplex Healing of Selectively Thiolated Guanosine Mismatches through a Cd2+ Chemical Stimulus.

    Science.gov (United States)

    Lunn, Samantha M L; Hribesh, Samira; Whitfield, Colette J; Hall, Michael J; Houlton, Andrew; Bronowska, Agnieszka K; Tuite, Eimer M; Pike, Andrew R

    2018-03-25

    The on-column selective conversion of guanosine to thioguanosine (tG) yields modified oligomers that exhibit destabilisation over the fully complementary duplex. Restoration to a stabilised duplex is induced through thio-directed Cd 2+ coordination; a route for healing DNA damage. Short oligomers are G-specifically thiolated through a modified on-column protocol without the need for costly thioguanosine phosphoramidites. Addition of Cd 2+ ions to a duplex containing a highly disrupted tG central mismatch sequence, 3'-A 6 tG 4 T 6 -5', suggests a (tG) 8 Cd 2 central coordination regime, resulting in increased base stacking and duplex stability. Equilibrium molecular dynamic calculations support the hypothesis of metal-induced healing of the thiolated duplex. The 2 nm displacement of the central tG mismatched region is dramatically reduced after the addition of a chemical stimuli, Cd 2+ ions, returning to a minimized fluctuational state comparable to the unmodified fully complementary oligomer. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Concurrent infections of pseudorabies virus and porcine bocavirus in China detected by duplex nanoPCR.

    Science.gov (United States)

    Luo, Yakun; Liang, Lin; Zhou, Ling; Zhao, Kai; Cui, Shangjin

    2015-07-01

    Nanoparticle-assisted polymerase chain reaction (nanoPCR) is a novel method for the simple, rapid, and specific amplification of DNA and has been used to detect viruses. A duplex nanoPCR molecular detection system was developed to detect pseudorabies virus (PRV) and porcine bocavirus (PBoV). Primers were selected to target conserved regions within the PRV gE gene and the PBoV NS1 gene. Under optimized nanoPCR reaction conditions, two specific fragments of 316 bp (PRV) and 996 bp (PBoV) were amplified by the duplex nanoPCR with a detection limit of 6 copies for PRV and 95 copies for PBoV; no fragments were amplified when other porcine viruses were used as template. When used to test 550 clinical samples, the duplex nanoPRC assay and a conventional duplex PCR assay provided very similar results (98.1% consistency); single PRV infections, single PBoV infections, and concurrent PRV and PBoV infections were detected in 37%, 15%, and 9% of the samples, respectively. The results indicate that the novel duplex nanoPCR assay is useful for the rapid detection of PRV and PBoV in pigs. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Surgical retroperitoneoscopic and transperitoneoscopic access in varicocelectomy: duplex scan results in pediatric population.

    Science.gov (United States)

    Mancini, Stefano; Bulotta, Anna Lavinia; Molinaro, Francesco; Ferrara, Francesco; Tommasino, Giulio; Messina, Mario

    2014-12-01

    This is a retrospective study to compare duplex scan results of laparoscopic Palomo's technique through retroperitoneal and transperitoneal approach for varicocelectomy in children. We statistically analyzed recurrence, testicular volume growth and complications. Surgical intervention was performed utilizing transperitoneoscopic (group A) or retroperitoneoscopic access (group B). Duplex scan control was performed after 12 months (T1), after 2 years (T2) and the last one at 18 years old in most patients. Statistical analysis was performed using the t-test for parametric data. Differences in proportions were evaluated using χ2 or Fisher's exact test. We treated 120 children (age range 10-17 years) who presented an asymptomatic IV grade of reflux, Coolsaet 1, associated with a left testicular hypotrophy in 36.6% of the cases (44 patients). No post-operative complications were verified. Duplex scan exam showed an increase of left testicular growth in both groups, with complete hypotrophy disappear in patients in both groups after 24 months. Hydrocele, diagnosed clinically and confirmed with duplex scan, was the most frequent post-operative complication (22/120 cases; 18.3%). This study showed the importance of duplex scan at all steps of this vascular pathology in children, and that there is no significantly difference in results between the two surgical techniques except for hydrocele in transperitoneoscopic access. Copyright © 2014 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  18. Heat treatment temperature influence on ASTM A890 GR 6A super duplex stainless steel microstructure

    International Nuclear Information System (INIS)

    Martins, Marcelo; Casteletti, Luiz Carlos

    2005-01-01

    Duplex and super duplex stainless steels are ferrous alloys with up to 26% chromium, 8% nickel, 5% molybdenum and 0.3% nitrogen, which are largely used in applications in media containing ions from the halogen family, mainly the chloride ion (Cl - ). The emergence of this material aimed at substituting Copper-Nickel alloys (Cupro-Nickel) that despite presenting good corrosion resistance, has mechanical properties quite inferior to steel properties. The metallurgy of duplex and super duplex stainless steel is complex due to high sensitiveness to sigma phase precipitation that becomes apparent, due to the temperatures they are exposed on cooling from solidification as well as from heat treatment processes. The objective of this study was to verify the influence of heat treating temperatures on the microstructure and hardness of ASTM A890/A890M Gr 6A super duplex stainless steel type. Microstructure control is of extreme importance for castings, as the chemical composition and cooling during solidification inevitably provide conditions for precipitation of sigma phase. Higher hardness in these materials is directly associated to high sigma phase concentration in the microstructure, precipitated in the ferrite/austenite interface. While heat treatment temperature during solution treatment increases, the sigma phase content in the microstructure decreases and consequently, the material hardness diminishes. When the sigma phase was completely dissolved by the heat treatment, the material hardness was influenced only due to ferrite and austenite contents in the microstructure

  19. Behavior of duplex stainless steel casting defects under mechanical loadings

    International Nuclear Information System (INIS)

    Jayet-Gendrot, S.; Gilles, P.

    2000-01-01

    Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied under the most severe assumptions: presence of a large defect, accidental loadings and end-of-life material properties accounting for its thermal aging embrittlement at the service temperature. The casting defects are idealized as semi-circular surface cracks or notches that have envelope dimensions. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster's envelope. The results show that shrinkage cavities are far less harmful than envelope notches thanks to the metal bridges between cavities. Under fatigue loadings, the generalized initiation of a cluster of cavities (defined when the cluster becomes a crack of the same global size) is reached for a number of cycles that is much higher than the one leading to the initiation of a notch. In the case of monotonic loadings, specimens with casting defects offer a very high resistance to ductile tearing. The tests are analyzed in order to develop a method that takes into account the behavior of casting defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modeling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (orig.)

  20. Full-Duplex Digital Communication on a Single Laser Beam

    Science.gov (United States)

    Hazzard, D. A.; MacCannell, J. A.; Lee, G.; Selves, E. R.; Moore, D.; Payne, J. A.; Garrett, C. D.; Dahlstrom, N.; Shay, T. M.

    2006-01-01

    A proposed free-space optical communication system would operate in a full-duplex mode, using a single constant-power laser beam for transmission and reception of binary signals at both ends of the free-space optical path. The system was conceived for two-way data communication between a ground station and a spacecraft in a low orbit around the Earth. It has been estimated that in this application, a data rate of 10 kb/s could be achieved at a ground-station-to-spacecraft distance of 320 km, using a laser power of only 100 mW. The basic system concept is also applicable to terrestrial free-space optical communications. The system (see figure) would include a diode laser at one end of the link (originally, the ground station) and a liquid-crystal- based retroreflecting modulator at the other end of the link (originally, the spacecraft). At the laser end, the beam to be transmitted would be made to pass through a quarter-wave plate, which would convert its linear polarization to right circular polarization. For transmission of data from the laser end to the retroreflector end, the laser beam would be modulated with subcarrier phase-shift keying (SC-PSK). The transmitted beam would then pass through an aperture- sharing element (ASE) - basically, a mirror with a hole in it, used to separate the paths of the transmitted and received light beams. The transmitted beam would continue outward through a telescope (which, in the original application, would be equipped with a spacecraft-tracking system) that would launch the transmitted beam along the free-space optical path to the retroreflector end.

  1. Validation of a novel duplex ultrasound objective structured assessment of technical skills (DUOSATS) for arterial stenosis detection.

    Science.gov (United States)

    Jaffer, U; Singh, P; Pandey, V A; Aslam, M; Standfield, N J

    2014-01-01

    Duplex ultrasound facilitates bedside diagnosis and hence timely patient care. Its uptake has been hampered by training and accreditation issues. We have developed an assessment tool for Duplex arterial stenosis measurement for both simulator and patient based training. A novel assessment tool: duplex ultrasound assessment of technical skills was developed. A modified duplex ultrasound assessment of technical skills was used for simulator training. Novice, intermediate experience and expert users of duplex ultrasound were invited to participate. Participants viewed an instructional video and were allowed ample time to familiarize with the equipment. Participants' attempts were recorded and independently assessed by four experts using the modified duplex ultrasound assessment of technical skills. 'Global' assessment was also done on a four point Likert scale. Content, construct and concurrent validity as well as reliability were evaluated. Content and construct validity as well as reliability were demonstrated. The simulator had good satisfaction rating from participants: median 4; range 3-5. Receiver operator characteristic analysis has established a cut point of 22/ 34 and 25/ 40 were most appropriate for simulator and patient based assessment respectively. We have validated a novel assessment tool for duplex arterial stenosis detection. Further work is underway to establish transference validity of simulator training to improved skill in scanning patients. We have developed and validated duplex ultrasound assessment of technical skills for simulator training.

  2. Development of a panel of seven duplex real-time PCR assays for detecting 13 streptococcal superantigens.

    Science.gov (United States)

    Yang, Peng; Peng, Xiaomin; Cui, Shujuan; Shao, Junbin; Zhu, Xuping; Zhang, Daitao; Liang, Huijie; Wang, Quanyi

    2013-07-30

    Streptococcal superantigens (SAgs) are the major virulence factors of infection in humans for group A Streptococcus (GAS) bacteria. A panel consisting of seven duplex real-time PCR assays was developed to simultaneously detect 13 streptococcal SAgs and one internal control which may be important in the control of GAS-mediated diseases. Primer and probe sequences were selected based on the highly conserved region from an alignment of nucleotide sequences of the 13 streptococcal SAgs. The reaction conditions of the duplex real-time PCR were optimized and the specificity of the duplex assays was evaluated using SAg positive strains. The limit of detection of the duplex assays was determined by using 10-fold serial dilutions of the DNA of 13 streptococcal SAgs and compared to a conventional polymerase chain reaction (PCR) method for evaluating the duplex assays sensitivity. Using the duplex assays, we were able to differentiate between 13 SAgs from Streptococcus strains and other non-Streptococcus bacteria without cross-reaction. On the other hand, the limit of detection of the duplex assays was at least one or two log dilutions lower than that of the conventional PCR. The panel was highly specific (100%) and the limit of detection of these duplex groups was at least ten times lower than that obtained by using a conventional PCR method.

  3. Dwell-Time Distribution, Long Pausing and Arrest of Single-Ribosome Translation through the mRNA Duplex.

    Science.gov (United States)

    Xie, Ping

    2015-10-09

    Proteins in the cell are synthesized by a ribosome translating the genetic information encoded on the single-stranded messenger RNA (mRNA). It has been shown that the ribosome can also translate through the duplex region of the mRNA by unwinding the duplex. Here, based on our proposed model of the ribosome translation through the mRNA duplex we study theoretically the distribution of dwell times of the ribosome translation through the mRNA duplex under the effect of a pulling force externally applied to the ends of the mRNA to unzip the duplex. We provide quantitative explanations of the available single molecule experimental data on the distribution of dwell times with both short and long durations, on rescuing of the long paused ribosomes by raising the pulling force to unzip the duplex, on translational arrests induced by the mRNA duplex and Shine-Dalgarno(SD)-like sequence in the mRNA. The functional consequences of the pauses or arrests caused by the mRNA duplex and the SD sequence are discussed and compared with those obtained from other types of pausing, such as those induced by "hungry" codons or interactions of specific sequences in the nascent chain with the ribosomal exit tunnel.

  4. A Commentary on "Updating the Duplex Design for Test-Based Accountability in the Twenty-First Century"

    Science.gov (United States)

    Brandt, Steffen

    2010-01-01

    This article presents the author's commentary on "Updating the Duplex Design for Test-Based Accountability in the Twenty-First Century," in which Isaac I. Bejar and E. Aurora Graf propose the application of a test design--the duplex design (which was proposed in 1988 by Bock and Mislevy) for application in current accountability assessments.…

  5. In-Band Full-Duplex Communications for Cellular Networks with Partial Uplink/Downlink Overlap

    KAUST Repository

    AlAmmouri, Ahmad

    2015-12-06

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization in cellular networks. However, the explicit impact of spatial interference, imposed by FD communications, on uplink and downlink transmissions has been overlooked in the literature. This paper presents an extensive study of the explicit effect of FD communications on the uplink and downlink performances. For the sake of rigorous analysis, we develop a tractable framework based on stochastic geometry toolset. The developed model accounts for uplink truncated channel inversion power control in FD cellular networks. The study shows that FD communications improve the downlink throughput at the expense of significant degradation in the uplink throughput. Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between uplink and downlink frequency bands. To this end, we show that the amount of the overlap can be optimized via adjusting α to achieve a certain design objective.

  6. In-Band Full-Duplex Communications for Cellular Networks with Partial Uplink/Downlink Overlap

    KAUST Repository

    Alammouri, Ahmad; Elsawy, Hesham; Amin, Osama; Alouini, Mohamed-Slim

    2015-01-01

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization in cellular networks. However, the explicit impact of spatial interference, imposed by FD communications, on uplink and downlink transmissions has been overlooked in the literature. This paper presents an extensive study of the explicit effect of FD communications on the uplink and downlink performances. For the sake of rigorous analysis, we develop a tractable framework based on stochastic geometry toolset. The developed model accounts for uplink truncated channel inversion power control in FD cellular networks. The study shows that FD communications improve the downlink throughput at the expense of significant degradation in the uplink throughput. Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between uplink and downlink frequency bands. To this end, we show that the amount of the overlap can be optimized via adjusting α to achieve a certain design objective.

  7. Duplex sonography and magnetic resonance imaging in the clarification of nephrological complications after renal transplant

    International Nuclear Information System (INIS)

    Gueckel, C.; Krestin, G.P.; Wienand, P.

    1989-01-01

    A prospective study compared Duplex sonography and magnetic resonance imaging in evaluating renal transplant. Hundred and two Duplex sonographic and 24 MR examinations were performed and correlated with clinical course or biopsy. All normal renal allografts, 6 transplants with acute tubular necrosis and 2 cases of cyclosporin toxicity had normal Doppler waveforms, whereas 9 renal transplants with evidence of interstitial rejection by biopsy showed an obliteration or reversal of diastolic flow. MR imaging was less specific in identifying allograft rejection. There were false positive results in normal renal transplants, allografts with acute tubular necrosis and after rejection therapy. With regard to cost, accessibility and specificity, Duplex sonography is the method of choice for the evaluation of renal allografts. (orig.) [de

  8. Development of dansyl-modified oligonucleotide probes responding to structural changes in a duplex.

    Science.gov (United States)

    Suzuki, Yoshio; Kowata, Keiko; Komatsu, Yasuo

    2013-11-15

    We have synthesized a nonnucleoside amidite block of dansyl fluorophore to prepare dansyl-modified oligonucleotides (ONTs). The fluorescence intensities of dansyl-ONT specifically increased by the presence of adjacent guanosine residues but, significantly reduced in a dansyl-flipping duplex. These changes were caused by solvatochromism effect due to the number of guanine which is hydrophobic functional group and the external environment of dansyl group. The fluorescence intensities could be plotted as a function of the ONTs concentrations and the increase in the fluorescence was observed to equimolar concentrations of target DNA. This duplex exhibited higher melting temperature relative to the corresponding duplexes containing other base pairs. Similar changes in fluorescence could be detected upon hybridization with complementary RNAs. Thus, the dansyl-modified ONTs provide sequence specific fluorescent probe of DNA and RNA. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Oxide thickness measurement technique for duplex-layer Zircaloy-4 cladding

    International Nuclear Information System (INIS)

    McClelland, R.G.; O'Leary, P.M.

    1992-01-01

    Siemens Nuclear Power Corporation (SNP) is investigating the use of duplex-layer Zircaloy-4 tubing to improve the waterside corrosion resistance of cladding for high-burnup pressurized water reactor (PWR) fuel designs. Standard SNP PWR cladding is typically 0.762-mm (0.030-in.)-thick Zircaloy-4. The SNP duplex cladding is nominally 0.660-mm (0.026-in.)-thick Zircalloy-4 with an ∼0.102-mm (0.004-in.) outer layer of another, more corrosion-resistant, zirconium-based alloy. It is common industry practice to monitor the in-reactor corrosion behavior of Zircaloy cladding by using an eddy-current 'lift-off' technique to measure the oxide thickness on the outer surface of the fuel cladding. The test program evaluated three different cladding samples, all with the same outer diameter and wall thickness: Zircaloy-4 and duplex clad types D2 and D4

  10. Throughput maximization for buffer-aided hybrid half-/full-duplex relaying with self-interference

    KAUST Repository

    Khafagy, Mohammad Galal

    2015-06-01

    In this work, we consider a two-hop cooperative setting where a source communicates with a destination through an intermediate relay node with a buffer. Unlike the existing body of work on buffer-aided half-duplex relaying, we consider a hybrid half-/full-duplex relaying scenario with loopback interference in the full-duplex mode. Depending on the channel outage and buffer states that are assumed available at the transmitters, the source and relay may either transmit simultaneously or revert to orthogonal transmission. Specifically, a joint source/relay scheduling and relaying mode selection mechanism is proposed to maximize the end-to-end throughput. The throughput maximization problem is converted to a linear program where the exact global optimal solution is efficiently obtained via standard convex/linear numerical optimization tools. Finally, the theoretical findings are corroborated with event-based simulations to provide the necessary performance validation.

  11. Alternate transmission relaying based on interference alignment in 3-relay half-duplex MIMO systems

    KAUST Repository

    Park, Seongho; Park, Kihong; Ko, Youngchai; Alouini, Mohamed-Slim

    2012-01-01

    In a half-duplex relaying, the capacity pre-log factor 1/2 is a major drawback in spectral efficiency. This paper proposes a linear precoding/decoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can suppress the inter-relay interference resulting from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2012 IEEE.

  12. Duplex System with Ectopic Ureter Opens into the Posterior Urethra: Case Report.

    Science.gov (United States)

    Milicevic, Snjezana; Bijelic, Radojka; Krivokuca, Vladimir; Jakovljevic, Branislava

    2018-04-01

    Duplicated ureter or Duplex Collecting System is a congenital condition in which the ureteric bud, the embryological origin of the ureter, arises twice, resulting in two ureters draining a single kidney. This congenital anomaly is rare, and even rarer when the duplex system with ectopic ureter is present. This type of congenital anomaly is even more rarely diagnosed and surgically treated in adulthood. This case report presents a case of a 32-year-old male, who had a duplex collecting system with two ureters on the left side. Ectopic ureter, draining the upper pole of the left kidney, opened into the posterior urethra. In our patient, taking into account the clinical perspective, the renal tissue damaging of the upper pole which was not functional, partial nephrectomy and ureterectomy was successfully performed.

  13. Approximation methods for the stability analysis of complete synchronization on duplex networks

    Science.gov (United States)

    Han, Wenchen; Yang, Junzhong

    2018-01-01

    Recently, the synchronization on multi-layer networks has drawn a lot of attention. In this work, we study the stability of the complete synchronization on duplex networks. We investigate effects of coupling function on the complete synchronization on duplex networks. We propose two approximation methods to deal with the stability of the complete synchronization on duplex networks. In the first method, we introduce a modified master stability function and, in the second method, we only take into consideration the contributions of a few most unstable transverse modes to the stability of the complete synchronization. We find that both methods work well for predicting the stability of the complete synchronization for small networks. For large networks, the second method still works pretty well.

  14. Alternate transmission relaying based on interference alignment in 3-relay half-duplex MIMO systems

    KAUST Repository

    Park, Seongho

    2012-09-01

    In a half-duplex relaying, the capacity pre-log factor 1/2 is a major drawback in spectral efficiency. This paper proposes a linear precoding/decoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can suppress the inter-relay interference resulting from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2012 IEEE.

  15. Interference alignment for degrees of freedom improvement in 3-relay half-duplex systems

    KAUST Repository

    Park, Seongho

    2011-12-01

    In a half-duplex relaying, the capacity pre-log factor is a major drawback in spectral efficiency. This paper proposes a linear precoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can eliminate the inter-relay interference resulted from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2011 IEEE.

  16. Hsc70/Hsp90 chaperone machinery mediates ATP-dependent RISC loading of small RNA duplexes.

    Science.gov (United States)

    Iwasaki, Shintaro; Kobayashi, Maki; Yoda, Mayuko; Sakaguchi, Yuriko; Katsuma, Susumu; Suzuki, Tsutomu; Tomari, Yukihide

    2010-07-30

    Small silencing RNAs--small interfering RNAs (siRNAs) or microRNAs (miRNAs)--direct posttranscriptional gene silencing of their mRNA targets as guides for the RNA-induced silencing complex (RISC). Both siRNAs and miRNAs are born double stranded. Surprisingly, loading these small RNA duplexes into Argonaute proteins, the core components of RISC, requires ATP, whereas separating the two small RNA strands within Argonaute does not. Here we show that the Hsc70/Hsp90 chaperone machinery is required to load small RNA duplexes into Argonaute proteins, but not for subsequent strand separation or target cleavage. We envision that the chaperone machinery uses ATP and mediates a conformational opening of Ago proteins so that they can receive bulky small RNA duplexes. Our data suggest that the chaperone machinery may serve as the driving force for the RISC assembly pathway. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Plastomes of the green algae Hydrodictyon reticulatum and Pediastrum duplex (Sphaeropleales, Chlorophyceae

    Directory of Open Access Journals (Sweden)

    Hilary A. McManus

    2017-05-01

    Full Text Available Background Comparative studies of chloroplast genomes (plastomes across the Chlorophyceae are revealing dynamic patterns of size variation, gene content, and genome rearrangements. Phylogenomic analyses are improving resolution of relationships, and uncovering novel lineages as new plastomes continue to be characterized. To gain further insight into the evolution of the chlorophyte plastome and increase the number of representative plastomes for the Sphaeropleales, this study presents two fully sequenced plastomes from the green algal family Hydrodictyaceae (Sphaeropleales, Chlorophyceae, one from Hydrodictyon reticulatum and the other from Pediastrum duplex. Methods Genomic DNA from Hydrodictyon reticulatum and Pediastrum duplex was subjected to Illumina paired-end sequencing and the complete plastomes were assembled for each. Plastome size and gene content were characterized and compared with other plastomes from the Sphaeropleales. Homology searches using BLASTX were used to characterize introns and open reading frames (orfs ≥ 300 bp. A phylogenetic analysis of gene order across the Sphaeropleales was performed. Results The plastome of Hydrodictyon reticulatum is 225,641 bp and Pediastrum duplex is 232,554 bp. The plastome structure and gene order of H. reticulatum and P. duplex are more similar to each other than to other members of the Sphaeropleales. Numerous unique open reading frames are found in both plastomes and the plastome of P. duplex contains putative viral protein genes, not found in other Sphaeropleales plastomes. Gene order analyses support the monophyly of the Hydrodictyaceae and their sister relationship to the Neochloridaceae. Discussion The complete plastomes of Hydrodictyon reticulatum and Pediastrum duplex, representing the largest of the Sphaeropleales sequenced thus far, once again highlight the variability in size, architecture, gene order and content across the Chlorophyceae. Novel intron insertion sites and unique

  18. Tricriticality in the q-neighbor Ising model on a partially duplex clique.

    Science.gov (United States)

    Chmiel, Anna; Sienkiewicz, Julian; Sznajd-Weron, Katarzyna

    2017-12-01

    We analyze a modified kinetic Ising model, a so-called q-neighbor Ising model, with Metropolis dynamics [Phys. Rev. E 92, 052105 (2015)PLEEE81539-375510.1103/PhysRevE.92.052105] on a duplex clique and a partially duplex clique. In the q-neighbor Ising model each spin interacts only with q spins randomly chosen from its whole neighborhood. In the case of a duplex clique the change of a spin is allowed only if both levels simultaneously induce this change. Due to the mean-field-like nature of the model we are able to derive the analytic form of transition probabilities and solve the corresponding master equation. The existence of the second level changes dramatically the character of the phase transition. In the case of the monoplex clique, the q-neighbor Ising model exhibits a continuous phase transition for q=3, discontinuous phase transition for q≥4, and for q=1 and q=2 the phase transition is not observed. On the other hand, in the case of the duplex clique continuous phase transitions are observed for all values of q, even for q=1 and q=2. Subsequently we introduce a partially duplex clique, parametrized by r∈[0,1], which allows us to tune the network from monoplex (r=0) to duplex (r=1). Such a generalized topology, in which a fraction r of all nodes appear on both levels, allows us to obtain the critical value of r=r^{*}(q) at which a tricriticality (switch from continuous to discontinuous phase transition) appears.

  19. Development of duplex RT-PCR-ELISA for the simultaneous detection of hepatitis A virus and hepatitis E virus.

    Science.gov (United States)

    Tahk, Hongmin; Lee, Min Hwa; Lee, Kang Bum; Cheon, Doo-Sung; Choi, Changsun

    2011-07-01

    This study aimed to develop a specific and sensitive duplex reverse transcription polymerase chain reaction enzyme-linked immunosorbent assay (duplex RT-PCR-ELISA) for hepatitis A virus (HAV) and hepatitis E virus (HEV). Duplex RT-PCR-ELISA could detect and differentiate HAV and HEV with specific probes. When ELISA technique was used to detect probe-bound RT-PCR products, duplex RT-PCR-ELISA could detect as little as 0.1 ng/μL HAV and HEV from clinical samples. Human norovirus, enterovirus, poliovirus, murine norovirus and feline calicivirus were used for the specificity test; all were negative. Therefore duplex RT-PCR-ELISA can be used for the simultaneous detection of HAV and HEV in contaminated fecal samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Fatigue crack propagation behavior and acoustic emission characteristics of the heat affected zone of super duplex stainless steel

    International Nuclear Information System (INIS)

    Do, Jae Yoon; Kim, Jin Hwan; Ahn, Seok Hwan; Park, In Duck; Kang, Chang Yong; Nam, Ki Woo

    2002-01-01

    Because duplex stainless steel shows the good strength and corrosion resistance properties, the necessity of duplex stainless steel, which has long life in severe environments, has been increased with industrial development. The fatigue crack propagation behavior of Heat Affected Zone(HAZ) has been investigated in super duplex stainless steel. The fatigue crack propagation rate of HAZ of super duplex stainless steel was faster than that of base metal of super duplex stainless steel. We also analysed acoustic emission signals during the fatigue test with time-frequency analysis method. According to the results of time-frequency analysis, the frequency ranges of 200-400 kHz were obtained by striation and the frequency range of 500 kHz was obtained due to dimple and separate of inclusion

  1. Characterization of Duplex steel Uranus 76N during deformation and heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lecomte-Beckers, J.; Carton, M. [ASMA Department - Sector, Special Metallic Materials, University of Liege, Chemin des Chevreuils 1, 4000 Liege 1 (Belgium); Moureaux, P.; Habraken, A.M. [M and S Department - Sector, Mechanic of Solids and Material, University of Liege, Chemin des Chevreuils 1, 4000 Liege 1 (Belgium)

    2006-12-15

    Duplex Uranus 76N is characterized by metallography, thermal and mechanical analysis. The investigation shows that the microstructure of such a Duplex strongly depends on the cooling conditions determining the quantity of austenite formed in the ferrite matrix. Numerical simulations of 76N behavior during the rolling process and service life require the knowledge of the recrystallization state during rolling steps at high temperature, thermal parameters such as dilatation, density, specific heat, thermal diffusivity, thermal conductivity and mechanical constitutive laws. These material parameters are determined and presented in this study. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. A duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains.

    Science.gov (United States)

    Benacer, Douadi; Zain, Siti Nursheena Mohd; Lewis, John W; Khalid, Mohd Khairul Nizam Mohd; Thong, Kwai Lin

    2017-01-01

    This study aimed to develop a duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains. Primers were designed to target the rrs (LG1/LG2) and ligB (LP1/LP2) genes to confirm the presence of the Leptospira genus and the pathogenic species, respectively. The assay showed 100% specificity against 17 Leptospira strains with a limit of detection of 23.1pg/µl of leptospiral DNA and sensitivity of 103 leptospires/ml in both spiked urine and water. Our duplex endpoint PCR assay is suitable for rapid early detection of Leptospira with high sensitivity and specificity.

  3. Duplex sonography of the near-surface leg veins; Duplexsonographie der oberflaechlichen Beinvenen

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, E.

    2007-07-01

    The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins.

  4. Problems in repair-welding of duplex-treated tool steels

    Directory of Open Access Journals (Sweden)

    T. Muhič

    2009-01-01

    Full Text Available The present paper addresses problems in laser welding of die-cast tools used for aluminum pressure die-castings and plastic moulds. To extend life cycle of tools various surface improvements are used. These surface improvements significantly reduce weldability of the material. This paper presents development of defects in repair welding of duplex-treated tool steel. The procedure is aimed at reduction of defects by the newly developed repair laser welding techniques. Effects of different repair welding process parameters and techniques are considered. A microstructural analysis is conducted to detect defect formation and reveal the best laser welding method for duplex-treated tools.

  5. Deformation Induced Martensitic Transformation and Its Initial Microstructure Dependence in a High Alloyed Duplex Stainless Steel

    DEFF Research Database (Denmark)

    Xie, Lin; Huang, Tian Lin; Wang, Yu Hui

    2017-01-01

    Deformation induced martensitic transformation (DIMT) usually occurs in metastable austenitic stainless steels. Recent studies have shown that DIMT may occur in the austenite phase of low alloyed duplex stainless steels. The present study demonstrates that DIMT can also take place in a high alloyed...... Fe–23Cr–8.5Ni duplex stainless steel, which exhibits an unexpectedly rapid transformation from γ-austenite into α′-martensite. However, an inhibited martensitic transformation has been observed by varying the initial microstructure from a coarse alternating austenite and ferrite band structure...

  6. Adhesive wear of iron chromium nickel silicon manganese molybdenum niobium alloys with duplex structure

    International Nuclear Information System (INIS)

    Lugscheider, E.; Deppe, E.; Ambroziak, A.; Melzer, A.

    1991-01-01

    Iron nickel chromium manganese silicon and iron chromium nickel manganese silicon molybdenum niobium alloys have a so-called duplex structure in a wide concentration range. This causes an excellent resistance to wear superior in the case of adhesive stress with optimized concentrations of manganese, silicon, molybdenum and niobium. The materials can be used for welded armouring structures wherever cobalt and boron-containing alloy systems are not permissible, e.g. in nuclear science. Within the framework of pre-investigations for manufacturing of filling wire electrodes, cast test pieces were set up with duplex structure, and their wear behavior was examined. (orig.) [de

  7. Design of duplex low carbon steels for improved strength: weight applications

    Energy Technology Data Exchange (ETDEWEB)

    Koo, J.

    1977-08-01

    Duplex ferrite-martensite (DFM) steels with excellent combinations of strength and formability have been selected from first principles, and their microstructure-property relationships established through a systematic investigation of a series of ternary Fe/X/0.1 C steels (X being varying amount of Cr and Si). Duplex processing consists of initial austenitization and quenching to form 100% martensite, followed by annealing in the (..cap alpha.. + ..gamma..) range and subsequent quenching. The resultant DFM morphology is controlled by the type and amount of alloying element X.

  8. Determination of the chromium concentration of phase decomposition products in an aged duplex stainless steel

    International Nuclear Information System (INIS)

    Kuwano, Hisashi; Imamasu, Hisanao

    2006-01-01

    A commercial duplex stainless steel has been aged at 673 K for up to 55,000 h. The aging results in the phase decomposition of the ferrite in duplex stainless steel. The end products of the phase decomposition are a Fe-rich and a Cr-rich phase. The chromium concentration of these phases is determined by measuring the hyperfine magnetic field and the isomer shift using Moessbauer effect. The experimental results are compared with a phase diagram calculated for Fe-Cr-Ni ternary system at 673 K.

  9. Doppler color flow mapping of peripheral vessels: Comparison of angiodynography with conventional duplex US

    International Nuclear Information System (INIS)

    Merritt, C.R.B.; Bluth, E.I.; Sullivan, M.A.

    1986-01-01

    A new Doppler color flow imager was compared to duplex US in the evaluation of carotid and peripheral vessels in 50 patients. A 7.5-MHz transducer permitted simultaneous high-resolution real-time imaging of Doppler flow and tissue. The system was found to have excellent image quality and Doppler sensitivity. Flow characteristics and velocity measurements obtained with this system correlated well with those obtained using the duplex scanner and were obtained more quickly than with the conventional system, allowing more complete assessment of flow characteristics. Color Doppler flow imaging appears to be an extremely promising method for the rapid and effective evaluation of peripheral vascular flow

  10. Alpha prime effect on mechanical properties and corrosion resistance of UR 52N+ duplex stainless steel

    International Nuclear Information System (INIS)

    Fontes, Talita Filier

    2009-01-01

    Alpha prime phase leads to decreased corrosion resistance and mechanical properties losses of duplex stainless steels. In this work mechanical and electrochemical tests were performed in duplex stainless steel UR 52N+ aged at 475 degree C for various periods in order to determine the sensibility of these tests to alpha prime presence. Hardness tests showed a gradual increase in its values; on the other hand, impact tests revealed that the material aged for 12h losses about 80% of energy absorption capacity of the solution annealed sample. Notwithstanding cyclic polarization tests showed that significant changes are only noted for aging times greater than 96h. (author)

  11. Venous filling time using air-plethysmography correlates highly with great saphenous vein reflux time using duplex.

    Science.gov (United States)

    Lattimer, C R; Azzam, M; Kalodiki, E; Geroulakos, G

    2014-03-01

    Venous filling time (VFT90) is the time taken to reach 90% of the venous volume in the calf. It is recorded by air-plethysmography (APG(®)) and is assumed to measure global venous reflux duration. However, this has never been confirmed by duplex. The aim of the study was to compare VFT on APG to venous reflux time/duration (RT) measured simultaneously with duplex on the same patients. Twenty-six consecutive patients, M:F = 16:10, age (25-78), C1 = 1, C2 = 4, C3 = 8, C4a = 6, C4b = 4, C5 = 2, C6 = 1, underwent simultaneous APG with duplex. The venous filling index (VFI, mL/second), VFT90 (seconds), great saphenous vein (GSV) RT on duplex, averaged thigh GSV diameter and thigh length (length) between the APG sensor air-cuff and duplex transducer were recorded. The VFT100 was calculated by VFT90/0.9. The additional time taken to fill the thigh was achieved using the VFI, length and deep vein diameter (d), to determine the corrected reflux duration: CRD = VFT100 + (length × πd(2)/4 (1/VFI)). Twenty-five patients are presented. One patient with very mild reflux (VFT90 = 55.9 seconds) had an indeterminate endpoint on duplex and was excluded. The median (range) VFI and GSV diameter was 4.9(1.3-15.5) mL/second and 7(4-17) mm, respectively. The VFT90 and VFT100 both correlated with RT on duplex (Spearman, P duplex RT at 24 (16.9) versus 28 (20) seconds respectively, P duplex by performing simultaneous measurements. There was an excellent correlation between the VFT90 versus duplex RT, thereby comparing reverse flow in a single superficial vein against the legs overall venous haemodynamic status. These tests can both be used in the quantification of reflux.

  12. On the Performance of In-Band Full-Duplex Cooperative Communications

    KAUST Repository

    Khafagy, Mohammad Galal

    2016-06-01

    In-band full-duplex, by which radios may simultaneously transmit and receive over the same channel, has been always considered practically-unfeasible due to the prohibitively strong self-interference. Indeed, a freshly-generated transmit signal power is typically ten orders of magnitude higher than that of a naturally-attenuated received signal. While unable to manage such an overwhelming interference, wireless communications resorted to half-duplex operation, transmitting and receiving over orthogonal channel resources. Recent research has demonstrated the practical feasibility of full-duplexing via successive sophisticated stages of signal suppression/cancellation, bringing this long-held assumption down and reviving the promising full-duplex potentials. Full-duplex relaying (FDR), where intermediate nodes may now support source-destination communication via simultaneous listening/forwarding, represents one of two full-duplex settings currently recommended for deployment in future fifth-generation (5G) systems. Theoretically, it has been widely accepted that FDR potentially doubles the channel capacity when compared to its half-duplex counterpart. Although FDR doubles the multiplexing gain, the effective signal-to-noise ratio (SNR) can be significantly degraded due to the residual self-interference (RSI) if not properly handled. In this work, efficient protocols are devised for different FDR settings. Selective cooperation is proposed for the canonical three-terminal FDR channel with RSI, which exploits the cooperative diversity offered by the independently fading source/relay message replicas arriving at the destination. Closed-form expressions are derived for the end-to-end SNR cumulative distribution function (CDF) under Rayleigh and Nakagami-m fading. Further, the offered diversity gain is presented as a function of the RSI scaling trend with the relay power. We show that the existing diversity problem in simple FDR protocols can be considerably fixed via

  13. Predictors of diagnostic success with renal artery duplex ultrasonography.

    Science.gov (United States)

    Hedayati, Nasim; Del Pizzo, David J; Harris, Sean E; Kuskowski, Michael; Pevec, William C; Lee, Eugene S; Pifer, Christy; Dawson, David L

    2011-05-01

    Renal artery duplex ultrasonography (RA-DUS) is commonly used for the evaluation and follow-up of renal artery atherosclerotic disease. In a complete study, renal artery flow is evaluated from the vessel origin to the intraparenchymal branches. The quality of RA-DUS is in part technologist-dependent, but many factors may affect the ability to complete a diagnostic examination. This study evaluated the clinical and technical factors that predict the ability to obtain a complete RA-DUS examination. A prospective evaluation of all patients undergoing RA-DUS between July 2008 and February 2009 was performed. Factors such as patient age, gender, body mass index, technologists' years of experience, patient care setting (inpatient vs. outpatient), bedside examination, smoking before the examination, fasting status, and recent abdominal surgery were all recorded. Multivariate logistic regression analysis was performed. A p value of ≤ 0.05 was considered significant. During the study period, 250 patients underwent RA-DUS (mean age: 59.9 ± 17.8 years, 57% [143] female). A total of 87 (35%) examinations were incomplete. This included nondiagnostic examinations which did not exhibit any segment of the renal artery. Factors that were associated with an incomplete examination included technologists' years of experience (OR = 0.92, p = 0.042), bedside examination (OR = 4.17, p = 0.016), and recent abdominal surgery (OR = 3.45, p = 0.047). Body mass index, fasting status, and smoking before the examination did not affect the ability to obtain a complete study. One-third of the RA-DUS studies were classified as incomplete by the strict criteria used in this prospective study. An experienced ultrasound technologist is more likely to obtain a complete RA-DUS examination. Recent abdominal surgery and bedside examinations were predictive of a limited examination as well. Vascular laboratories should consider these factors when scheduling examinations so as to obtain complete RA

  14. Two-dimensional 1H and 31P NMR spectra of a decamer oligodeoxyribonucleotide duplex and a quinoxaline ([MeCys3, MeCys7]TANDEM) drug duplex complex

    International Nuclear Information System (INIS)

    Powers, R.; Olsen, R.K.; Gorenstein, D.G.

    1989-01-01

    Assignment of the 1H and 31P NMR spectra of a decamer oligodeoxyribonucleotide duplex, d(CCCGATCGGG), and its quinoxaline ([MeCys3, MeCys7]TANDEM) drug duplex complex has been made by two-dimensional 1H-1H and heteronuclear 31P-1H correlated spectroscopy. The 31P chemical shifts of this 10 base pair oligonucleotide follow the general observation that the more internal the phosphate is located within the oligonucleotide sequence, the more upfield the 31P resonance occurs. While the 31P chemical shifts show sequence-specific variations, they also do not generally follow the Calladine rules previously demonstrated. 31P NMR also provides a convenient monitor of the phosphate ester backbone conformational changes upon binding of the drug to the duplex. Although the quinoxaline drug, [MeCys3, MeCys7]TANDEM, is generally expected to bind to duplex DNA by bis-intercalation, only small 31P chemical shift changes are observed upon binding the drug to duplex d(CCCGATCGGG). Additionally, only small perturbations in the 1H NMR and UV spectra are observed upon binding the drug to the decamer, although association of the drug stabilizes the duplex form relative to the other states. These results are consistent with a non-intercalative mode of association of the drug. Modeling and molecular mechanics energy minimization demonstrate that a novel structure in which the two quinoxaline rings of the drug binds in the minor groove of the duplex is possible

  15. Protein complexation with DNA phosphates as a cause for DNA duplex destabilization : a thermodynamic model

    NARCIS (Netherlands)

    Genderen, van M.H.P.; Buck, H.M.

    1989-01-01

    Complexation of positively charged sites in a protein with the negative DNA phosphate groups shields the phosphate charges. This diminishes interstrand electrostatic repulsions, which stabilizes the duplex. When phosphate shidlding is present in one DNA strand only, the conformation of this strand

  16. Triple helical DNA in a duplex context and base pair opening

    Science.gov (United States)

    Esguerra, Mauricio; Nilsson, Lennart; Villa, Alessandra

    2014-01-01

    It is fundamental to explore in atomic detail the behavior of DNA triple helices as a means to understand the role they might play in vivo and to better engineer their use in genetic technologies, such as antigene therapy. To this aim we have performed atomistic simulations of a purine-rich antiparallel triple helix stretch of 10 base triplets flanked by canonical Watson–Crick double helices. At the same time we have explored the thermodynamic behavior of a flipping Watson–Crick base pair in the context of the triple and double helix. The third strand can be accommodated in a B-like duplex conformation. Upon binding, the double helix changes shape, and becomes more rigid. The triple-helical region increases its major groove width mainly by oversliding in the negative direction. The resulting conformations are somewhere between the A and B conformations with base pairs remaining almost perpendicular to the helical axis. The neighboring duplex regions maintain a B DNA conformation. Base pair opening in the duplex regions is more probable than in the triplex and binding of the Hoogsteen strand does not influence base pair breathing in the neighboring duplex region. PMID:25228466

  17. Full-Duplex opportunistic relay selection in future spectrum-sharing networks

    KAUST Repository

    Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aï ssa, Sonia

    2015-01-01

    We propose and analyze the performance of full-duplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its end-to-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

  18. Sequence-specific protection of duplex DNA against restriction and methylation enzymes by pseudocomplementary PNAs

    DEFF Research Database (Denmark)

    Izvolsky, K I; Demidov, V V; Nielsen, P E

    2000-01-01

    I restriction endonuclease and dam methylase. The pcPNA-assisted protection against enzymatic methylation is more efficient when the PNA-binding site embodies the methylase-recognition site rather than overlaps it. We conclude that pcPNAs may provide the robust tools allowing to sequence-specifically manipulate...... DNA duplexes in a virtually sequence-unrestricted manner....

  19. Follow-up of renal and mesenteric artery revascularization with duplex ultrasonography

    Science.gov (United States)

    Taylor, David C.; Houston, Gordon T.M.; Anderson, Caroline; Jameson, Margot; Popatia, Shelley

    1996-01-01

    Objective To evaluate the long-term anatomic results of renal revascularization procedures using duplex ultrasonography. Design A case series. Setting A university-affiliated hospital. Patients Twenty-five patients who had undergone renal percutaneous transluminal angioplasty (PTA) (18 arteries), renal bypass (10 arteries) and mesenteric bypass (6 arteries). The mean follow-up was 22 months (range from 3 to 48 months) for those who underwent renal PTA, 23 months (range from 1.5 to 70 months) for those who underwent renal bypass and 34 months (range from 8 to 144 months) for those who underwent mesenteric bypass. Main Outcome Measures Patency rates for the three procedures as assessed by duplex ultrasonography. Results Duplex ultrasonography demonstrated patency without stenosis after renal and mesenteric artery revascularization in 14 arteries subjected to renal PTA, 9 arteries subjected to renal bypass and 6 arteries subjected to mesenteric bypass. Three arteries that had renal PTA had recurrent vessel stenosis and one had occlusion. One artery that had renal bypass showed occlusion. Conclusions Renal PTA, renal bypass and mesenteric bypass are durable procedures at 2 years of follow-up, and duplex ultrasonography is a valuable method for assessing the patency of arteries after renal and mesenteric revascularization. PMID:8599785

  20. Investigation of Selected Surface Integrity Features of Duplex Stainless Steel (DSS) after Turning

    Czech Academy of Sciences Publication Activity Database

    Krolczyk, G.; Nieslony, P.; Legutko, S.; Hloch, Sergej; Samardžić, I.

    2015-01-01

    Roč. 54, č. 1 (2015), s. 91-94 ISSN 0543-5846 Institutional support: RVO:68145535 Keywords : duplex stainless steel * machining * turning * surface integrity * surface roughness Subject RIV: JQ - Machines ; Tools Impact factor: 0.959, year: 2014 http://hrcak.srce.hr/126702

  1. The σ phase formation in annealed UNS S31803 duplex stainless steel: Texture aspects

    International Nuclear Information System (INIS)

    Souza, C.M.; Abreu, H.F.G.; Tavares, S.S.M.; Rebello, J.M.A.

    2008-01-01

    The influence of sigma phase precipitation on the texture of austenite in a duplex stainless steel UNS S31803 was investigated. Sigma phase quantification was precisely performed by electron backscattered scanning diffraction (EBSD) for some conditions. It was found that the increase of the sigma phase precipitation enhances the amount of Brass texture in the austenite phase

  2. Low-Temperature Mechanical Behavior of Super Duplex Stainless Steel with Sigma Precipitation

    OpenAIRE

    Kim, Seul-Kee; Kang, Ki-Yeob; Kim, Myung-Soo; Lee, Jae-Myung

    2015-01-01

    Experimental studies in various aspects have to be conducted to maintain stable applications of super duplex stainless steels (SDSS) because the occurrence rate of sigma phase, variable temperature and growth direction of sigma phase can influence mechanical performances of SDSS. Tensile tests of precipitated SDSS were performed under various temperatures to analyze mechanical and morphological behavior.

  3. Low-Temperature Mechanical Behavior of Super Duplex Stainless Steel with Sigma Precipitation

    Directory of Open Access Journals (Sweden)

    Seul-Kee Kim

    2015-09-01

    Full Text Available Experimental studies in various aspects have to be conducted to maintain stable applications of super duplex stainless steels (SDSS because the occurrence rate of sigma phase, variable temperature and growth direction of sigma phase can influence mechanical performances of SDSS. Tensile tests of precipitated SDSS were performed under various temperatures to analyze mechanical and morphological behavior.

  4. The design and analysis of AVTMR (all voting triple modular redundancy) and dual-duplex system

    International Nuclear Information System (INIS)

    Kim, Hyunki; Lee, Hyeuntae; Lee, Keyseo

    2005-01-01

    In this paper, we design AVTMR (All Voting Triple Modular Redundancy) and dual-duplex system which have a fault-tolerant characteristic, and two systems are compared in the evaluation of RAMS (Reliability, Availability, Maintainability and Safety) and MTTF (Mean Time To Failure). AVTMR system is designed in a triplicated voter technique and dual-duplex system in a comparator, and two systems are based on MC68000. To evaluate system characteristic, Markov modeling method is designed for reliability, availability, safety and MTTF (Mean Time To Failure), and RELEX6.0 tool is used for the calculation of failure rate of electrical components that is based on MILSPEC-217F. In this paper, we can see two systems are more high dependability than a single system, and AVTMR or dual-duplex system can be selected for a specific application system. Especially, because AVTMR and dual-duplex system have high RAMS better than a single system, they can be applied to life critical system such as an airplane and a high-speed railway system

  5. Ureterocystoplasty using the lower pole ureter of a duplex kidney with preservation of ipsilateral renal function

    OpenAIRE

    John Lazarus

    2012-01-01

    We describe the case of a 9 year old boy with neurogenic bladder dysfunction who co-incidentally had a unilateral duplex kidney with Grade 5 vesico-ureteric reflux into a poorly functioning lower moiety allowing heminephrectomy and ureterocystoplasty with preservation of ipsilateral renal function.

  6. Block compressed sensing for feedback reduction in relay-aided multiuser full duplex networks

    KAUST Repository

    Elkhalil, Khalil

    2016-08-11

    Opportunistic user selection is a simple technique that exploits the spatial diversity in multiuser relay-aided networks. Nonetheless, channel state information (CSI) from all users (and cooperating relays) is generally required at a central node in order to make selection decisions. Practically, CSI acquisition generates a great deal of feedback overhead that could result in significant transmission delays. In addition to this, the presence of a full-duplex cooperating relay corrupts the fed back CSI by additive noise and the relay\\'s loop (or self) interference. This could lead to transmission outages if user selection is based on inaccurate feedback information. In this paper, we propose an opportunistic full-duplex feedback algorithm that tackles the above challenges. We cast the problem of joint user signal-to-noise ratio (SNR) and the relay loop interference estimation at the base-station as a block sparse signal recovery problem in compressive sensing (CS). Using existing CS block recovery algorithms, the identity of the strong users is obtained and their corresponding SNRs are estimated. Numerical results show that the proposed technique drastically reduces the feedback overhead and achieves a rate close to that obtained by techniques that require dedicated error-free feedback from all users. Numerical results also show that there is a trade-off between the feedback interference and load, and for short coherence intervals, full-duplex feedback achieves higher throughput when compared to interference-free (half-duplex) feedback. © 2016 IEEE.

  7. Cyclic plastic response and fatigue life of duplex and superduplex stainless steel

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav

    43 2005, č. 4 (2005), s. 280-289 ISSN 0023-432X R&D Projects: GA ČR(CZ) GA106/02/0584 Institutional research plan: CEZ:AV0Z20410507 Keywords : duplex steel * fatigue life * cyclic plasticity Subject RIV: JG - Metallurgy Impact factor: 0.973, year: 2005

  8. On the Potential of Full Duplex Communication in 5G Small Cell Networks

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Berardinelli, Gilberto; Tavares, Fernando Menezes Leitão

    2015-01-01

    , the potential throughput gain may not be 100% as promised. In this study, we evaluate the performance of full duplex communication in a dense small cell scenario as targeted by future 5th Generation (5G) radio access technology under the ideal assumptions of a full buffer, always active traffic model...

  9. In-Band full-duplex transceiver technology for 5G mobile networks

    NARCIS (Netherlands)

    Deballie, B.; van Liempd, B.; Hershberg, B.; Craninckx, J.; Rikkinen, K.; van den Broek, Dirk-Jan; Klumperink, Eric A.M.; Nauta, Bram

    2015-01-01

    In-band full-duplex is a promising air interface technique to tackle several of the key challenges of next generation (5G)mobile networks. Simultaneous transmission and reception in the same frequency band increases the throughput and spectral efficiency, and reduces the air interface delay. Its

  10. Low-crosstalk full-duplex all-optical indoor wireless transmission with carrier recovery

    NARCIS (Netherlands)

    Oh, C.W.; Cao, Z.; Mekonnen, K.A.; Tangdiongga, E.; Koonen, A.M.J.

    2017-01-01

    We propose and demonstrate a novel bi-directional free-space (FS) optical wireless communication system for indoor wireless networks. A 2-D infrared beam-steered system supporting full-duplex communication of at least 10 Gb/s capacity per wireless terminal with simple NRZ-OOK modulation format is

  11. Influence of surface texture on the galling characteristics of lean duplex and austenitic stainless steels

    DEFF Research Database (Denmark)

    Wadman, Boel; Eriksen, J.; Olsson, M.

    2010-01-01

    Two simulative test methods were used to study galling in sheet forming of two types of stainless steel sheet: austenitic (EN 1.4301) and lean duplex LDX 2101 (EN 1.4162) in different surface conditions. The pin-on-disc test was used to analyse the galling resistance of different combinations of ...

  12. Templated Chemistry for Sequence-Specific Fluorogenic Detection of Duplex DNA

    Science.gov (United States)

    Li, Hao; Franzini, Raphael M.; Bruner, Christopher; Kool, Eric T.

    2015-01-01

    We describe the development of templated fluorogenic chemistry for detection of specific sequences of duplex DNA in solution. In this approach, two modified homopyrimidine oligodeoxynucleotide probes are designed to bind by triple helix formation at adjacent positions on a specific purine-rich target sequence of duplex DNA. One fluorescein-labeled probe contains an α-azidoether linker to a fluorescence quencher; the second (trigger) probe carries a triarylphosphine, designed to reduce the azide and cleave the linker. The data showed that at pH 5.6 these probes yielded a strong fluorescence signal within minutes on addition to a complementary homopurine duplex DNA target. The signal increased by a factor of ca. 60, and was completely dependent on the presence of the target DNA. Replacement of cytosine in the probes with pseudoisocytosine allowed the templated chemistry to proceed readily at pH 7. Single nucleotide mismatches in the target oligonucleotide slowed the templated reaction considerably, demonstrating high sequence selectivity. The use of templated fluorogenic chemistry for detection of duplex DNAs has not been previously reported and may allow detection of double stranded DNA, at least for homopurine-homopyrimidine target sites, under native, non-disturbing conditions. PMID:20859985

  13. Physical-Layer Security with Full-Duplex Transceivers and Multiuser Receiver at Eve

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Shafique Ansari, Imran; Popovski, Petar

    2017-01-01

    , leading researchers to study other possible applications that can accord higher gains. The potential of full-duplex communication in improving the physical-layer security of a communication link is investigated in this contribution. We specifically present a thorough analysis of the achievable ergodic...

  14. Full-Duplex opportunistic relay selection in future spectrum-sharing networks

    KAUST Repository

    Khafagy, Mohammad Galal

    2015-06-01

    We propose and analyze the performance of full-duplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its end-to-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

  15. Duplex surface treatment of AISI 1045 steel via plasma nitriding of chromized layer

    International Nuclear Information System (INIS)

    Hakami, F.; Sohi, M. Heydarzadeh; Ghani, J. Rasizadeh

    2011-01-01

    In this work AISI 1045 steel were duplex treated via plasma nitriding of chromized layer. Samples were pack chromized by using a powder mixture consisting of ferrochromium, ammonium chloride and alumina at 1273 K for 5 h. The samples were then plasma-nitrided for 5 h at 803 K and 823 K, in a gas mixture of 75%N 2 + 25%H 2 . The treated specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and Vickers micro-hardness test. The thickness of chromized layer before nitriding was about 8 μm and it was increased after plasma nitriding. According to XRD analysis, the chromized layer was composed of chromium and iron carbides. Plasma nitriding of chromized layer resulted in the formation of chromium and iron nitrides and carbides. The hardness of the duplex layers was significantly higher than the hardness of the base material or chromized layer. The main cause of the large improvement in surface hardness was due to the formation of Cr x N and Fe x N phases in the duplex treated layers. Increasing of nitriding temperature from 803 to 823 K enhanced the formation of CrN in the duplex treated layer and increased the thickness of the nitrided layer.

  16. Spectrum sharing opportunities of full-duplex systems using improper Gaussian signaling

    KAUST Repository

    Gaafar, Mohamed; Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2015-01-01

    half-duplex SU pair that uses IGS. The objective is to maximize the SU instantaneous achievable rate while meeting the PU quality-of-service. To this end, we propose a simplified algorithm that optimizes the SU signal parameters, i.e, the transmit power

  17. Yield stress of duplex stainless steel specimens estimated using a compound Hall–Petch equation

    Directory of Open Access Journals (Sweden)

    Noriaki Hirota, Fuxing Yin, Tsukasa Azuma and Tadanobu Inoue

    2010-01-01

    Full Text Available In this study, the 0.2% yield stress of duplex stainless steel was evaluated using a compound Hall–Petch equation. The compound Hall–Petch equation was derived from four types of duplex stainless steel, which contained 0.2–64.4 wt% δ-ferrite phase, had different chemical compositions and were annealed at different temperatures. Intragranular yield stress was measured with an ultra-microhardness tester and evaluated with the yield stress model proposed by Dao et al. Grain size, volume fraction and texture were monitored by electron backscattering diffraction measurement. The kγ constant in the compound equation for duplex stainless steel agrees well with that for γ-phase SUS316L steel in the temperature range of 1323–1473 K. The derived compound Hall–Petch equation predicts that the yield stress will be in good agreement with the experimental results for the Cr, Mn, Si, Ni and N solid-solution states. We find that the intragranular yield stress of the δ-phase of duplex stainless steel is rather sensitive to the chemical composition and annealing conditions, which is attributed to the size misfit parameter.

  18. Duplex scanning in the diagnosis of acute deep vein thrombosis of the lower extremity

    NARCIS (Netherlands)

    van Ramshorst, B.; Legemate, D. A.; Verzijlbergen, J. F.; Hoeneveld, H.; Eikelboom, B. C.; de Valois, J. C.; Meuwissen, O. J.

    1991-01-01

    In a prospective study the value of duplex scanning in the diagnosis of acute femoro-popliteal thrombosis was compared to conventional contrast venography (CV) as a gold standard. A total of 126 legs in 117 patients suspected of having deep vein thrombosis (DVT) or pulmonary embolism (PE) were

  19. Duplex investigations in children: Are clinical signs in children with venous disorders relevant?

    Science.gov (United States)

    Birgitte Maessen-Visch, M; Smeets, L; van Vleuten, C

    2015-12-01

    Ultra sound colored duplex sonography is the preferred method in diagnosing chronic venous disease. Data in children on incidence, indications, and results are lacking. From the total of 9180 duplex investigations performed in our hospital from 2009 to 2012, data on indication and results of the investigation as well as patient characteristics were evaluated retrospectively for the proportion of pediatric patients. Duplex investigations were performed 49 times in 38 children (6-18 years), with an average of 1.3 times (1-6 times) per child. Forty percent showed abnormalities: 17 times deep venous thrombosis was suspected; deep venous thrombosis was objectified in 18%. In the 21 investigations performed for varicosis-related complaints, varicose veins or venous malformations were objectified in 57%. Edema was never a symptom of chronic venous disease. Duplex investigation is not often performed in children. In children with established deep venous thrombosis, a family history with deep venous thrombosis is common. In general, edema was not seen in children with varicose veins and, therefore, does not seem a reliable clinical sign at young age. © The Author(s) 2014.

  20. The effect of a simulation training package on skill acquisition for duplex arterial stenosis detection.

    Science.gov (United States)

    Jaffer, Usman; Normahani, Pasha; Singh, Prashant; Aslam, Mohammed; Standfield, Nigel J

    2015-01-01

    In vascular surgery, duplex ultrasonography is a valuable diagnostic tool in patients with peripheral vascular disease, and there is increasing demand for vascular surgeons to be able to perform duplex scanning. This study evaluates the role of a novel simulation training package on vascular ultrasound (US) skill acquisition. A total of 19 novices measured predefined stenosis in a simulated pulsatile vessel using both peak systolic velocity ratio (PSVR) and diameter reduction (DR) methods before and after a short period of training using a simulated training package. The training package consisted of a simulated pulsatile vessel phantom, a set of instructional videos, duplex ultrasound objective structured assessment of technical skills (DUOSATS) tool, and a portable US scanner. Quantitative metrics (procedure time, percentage error using PSVR and DR methods, DUOSAT scores, and global rating scores) before and after training were compared. Subjects spent a median time of 144 mins (IQR: 60-195) training using the simulation package. Subjects exhibited statistically significant improvements when comparing pretraining and posttraining DUOSAT scores (pretraining = 17 [16-19.3] vs posttraining = 30 [27.8-31.8]; p duplex images in a pulsatile simulated phantom following a short period of goal direct training using a simulation training package. A simulation training package may be a valuable tool for integration into a vascular training program. However, further work is needed to explore whether these newly attained skills are translated into clinical assessment. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  1. Updating the Duplex Design for Test-Based Accountability in the Twenty-First Century

    Science.gov (United States)

    Bejar, Isaac I.; Graf, E. Aurora

    2010-01-01

    The duplex design by Bock and Mislevy for school-based testing is revisited and evaluated as a potential platform in test-based accountability assessments today. We conclude that the model could be useful in meeting the many competing demands of today's test-based accountability assessments, although many research questions will need to be…

  2. Base pairing and structural insights into the 5-formylcytosine in RNA duplex

    Science.gov (United States)

    Wang, Rui; Luo, Zhipu; He, Kaizhang; Delaney, Michael O.; Chen, Doris; Sheng, Jia

    2016-01-01

    Abstract 5-Formylcytidine (f5C), a previously discovered natural nucleotide in the mitochondrial tRNA of many species including human, has been recently detected as the oxidative product of 5-methylcytidine (m5C) through 5-hydroxymethylcytidine (hm5C) in total RNA of mammalian cells. The discovery indicated that these cytosine derivatives in RNA might also play important epigenetic roles similar as in DNA, which has been intensively investigated in the past few years. In this paper, we studied the base pairing specificity of f5C in different RNA duplex contexts. We found that the 5-formyl group could increase duplex thermal stability and enhance base pairing specificity. We present three high-resolution crystal structures of an octamer RNA duplex [5′-GUA(f5C)GUAC-3′]2 that have been solved under three crystallization conditions with different buffers and pH values. Our results showed that the 5-formyl group is located in the same plane as the cytosine base and forms an intra-residue hydrogen bond with the amino group in the N4 position. In addition, this modification increases the base stacking between the f5C and the neighboring bases while not causing significant global and local structure perturbations. This work provides insights into the effects of 5-formylcytosine on RNA duplex. PMID:27079978

  3. Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    Chiu, Liu Ho; Hsieh, Wen Chin

    2003-01-01

    An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ 2 and Cr 2 N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl 3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

  4. Duplex correlation phlebography in venous mapping of the upper limbs for artery venous fistulas for hemodialysis

    International Nuclear Information System (INIS)

    Esperon Percovich, A.; Lopez Chapuis, D.; Velverdu, M.; Curi, J.; Sciuto, F.; Velverdu, M.; Curi, J.

    1995-01-01

    When clinical evaluation is not enough,the evaluation of the venous condition of the upper limbs for the realization of angio access for hemodialysis is classically based on phlebography,an invasive,risky method.the appear rance of non invasive techniques such as eco Doppler(duplex) makes it necessary to do research in order to determine the utility of the method and define its indications.The authors analyse 35 venous mappings of the upper limbs by phlebography and duplex and compare its results for the different venous regions.They come to the conclusion that duplex presented the best performance for the hum ero axillary subclavian region,detecting thrombosis with a sensitivity of 100% a specificity of 97% positive predictive value of 50% and negative predictive value of 100%.For superficial axis (radial and superficial ulnar,basilic and cephalic)there is low sensitivity for the determination of presence and permeability of the axis but 100% specificity.Duplex was not useful for the description of veins in order to determine utility for Avf.Finally,the authors make recommendations as regards indications of these para clinical tests [es

  5. Sigma phase morphologies in cast and aged super duplex stainless steel

    International Nuclear Information System (INIS)

    Martins, Marcelo; Casteletti, Luiz Carlos

    2009-01-01

    Solution annealed and water quenched duplex and super duplex stainless steels are thermodynamically metastable systems at room temperature. These systems do not migrate spontaneously to a thermodynamically stable condition because an energy barrier separates the metastable and stable states. However, any heat input they receive, for example through isothermal treatment or through prolonged exposure to a voltaic arc in the welding process, cause them to reach a condition of stable equilibrium which, for super duplex stainless steels, means precipitation of intermetallic and carbide phases. These phases include the sigma phase, which is easily identified from its morphology, and its influence on the material's impact strength. The purpose of this work was to ascertain how 2-hour isothermal heat treatments at 920 deg. C and 980 deg. C affect the microstructure of ASTM A890/A890M GR 6A super duplex stainless steel. The sigma phase morphologies were found to be influenced by these two aging temperatures, with the material showing a predominantly lacy microstructure when heat treated at 920 deg. C and block-shaped when heat treated at 980 deg. C.

  6. Block compressed sensing for feedback reduction in relay-aided multiuser full duplex networks

    KAUST Repository

    Elkhalil, Khalil; Eltayeb, Mohammed; Kammoun, Abla; Al-Naffouri, Tareq Y.; Bahrami, Hamid Reza

    2016-01-01

    Opportunistic user selection is a simple technique that exploits the spatial diversity in multiuser relay-aided networks. Nonetheless, channel state information (CSI) from all users (and cooperating relays) is generally required at a central node in order to make selection decisions. Practically, CSI acquisition generates a great deal of feedback overhead that could result in significant transmission delays. In addition to this, the presence of a full-duplex cooperating relay corrupts the fed back CSI by additive noise and the relay's loop (or self) interference. This could lead to transmission outages if user selection is based on inaccurate feedback information. In this paper, we propose an opportunistic full-duplex feedback algorithm that tackles the above challenges. We cast the problem of joint user signal-to-noise ratio (SNR) and the relay loop interference estimation at the base-station as a block sparse signal recovery problem in compressive sensing (CS). Using existing CS block recovery algorithms, the identity of the strong users is obtained and their corresponding SNRs are estimated. Numerical results show that the proposed technique drastically reduces the feedback overhead and achieves a rate close to that obtained by techniques that require dedicated error-free feedback from all users. Numerical results also show that there is a trade-off between the feedback interference and load, and for short coherence intervals, full-duplex feedback achieves higher throughput when compared to interference-free (half-duplex) feedback. © 2016 IEEE.

  7. There is no benefit to universal carotid artery duplex screening before a major cardiac surgical procedure.

    Science.gov (United States)

    Adams, Brian C; Clark, Ross M; Paap, Christina; Goff, James M

    2014-01-01

    Perioperative stroke is a devastating complication after cardiac surgery. In an attempt to minimize this complication, many cardiac surgeons routinely preoperatively order carotid artery duplex scans to assess for significant carotid stenosis. We hypothesize that the routine screening of preoperative cardiac surgery patients with carotid artery duplex scans detects few patients who would benefit from carotid intervention or that a significant carotid stenosis reliably predicts stroke risk after cardiac surgery. A retrospective review identified 1,499 patients who underwent cardiac surgical procedures between July 1999 and September 2010. Data collected included patient demographics, comorbidities, history of previous stroke, preoperative carotid artery duplex scan results, location of postoperative stroke, and details of carotid endarterectomy (CEA) procedures before, in conjunction with, or after cardiac surgery. Statistical methods included univariate analysis and Fisher's exact test. Twenty-six perioperative strokes were identified (1.7%). In the 21 postoperative stroke patients for whom there is complete carotid artery duplex scan data, 3 patients had a hemodynamically significant lesion (>70%) and 1 patient underwent unilateral carotid CEA for bilateral disease. Postoperative strokes occurred in the anterior cerebral circulation (69.2%), posterior cerebral circulation (15.4%), or both (15.4%). Patient comorbidities, preoperative carotid artery duplex scan screening velocities, or types of cardiac surgical procedure were not predictive for stroke. Thirteen patients (0.86%) underwent CEA before, in conjunction with, or after cardiac surgery. Two of these patients had symptomatic disease, 1 of whom underwent CEA before and the other after his cardiac surgery. Of the 11 asymptomatic patients, 2 underwent CEA before, 3 concurrently, and 6 after cardiac surgery. Left main disease (≥50% stenosis), previous stroke, and peripheral vascular disease were found to be

  8. Numerical simulation of hydrogen-assisted crack initiation in austenitic-ferritic duplex steels

    International Nuclear Information System (INIS)

    Mente, Tobias

    2015-01-01

    Duplex stainless steels have been used for a long time in the offshore industry, since they have higher strength than conventional austenitic stainless steels and they exhibit a better ductility as well as an improved corrosion resistance in harsh environments compared to ferritic stainless steels. However, despite these good properties the literature shows some failure cases of duplex stainless steels in which hydrogen plays a crucial role for the cause of the damage. Numerical simulations can give a significant contribution in clarifying the damage mechanisms. Because they help to interpret experimental results as well as help to transfer results from laboratory tests to component tests and vice versa. So far, most numerical simulations of hydrogen-assisted material damage in duplex stainless steels were performed at the macroscopic scale. However, duplex stainless steels consist of approximately equal portions of austenite and δ-ferrite. Both phases have different mechanical properties as well as hydrogen transport properties. Thus, the sensitivity for hydrogen-assisted damage is different in both phases, too. Therefore, the objective of this research was to develop a numerical model of a duplex stainless steel microstructure enabling simulation of hydrogen transport, mechanical stresses and strains as well as crack initiation and propagation in both phases. Additionally, modern X-ray diffraction experiments were used in order to evaluate the influence of hydrogen on the phase specific mechanical properties. For the numerical simulation of the hydrogen transport it was shown, that hydrogen diffusion strongly depends on the alignment of austenite and δ-ferrite in the duplex stainless steel microstructure. Also, it was proven that the hydrogen transport is mainly realized by the ferritic phase and hydrogen is trapped in the austenitic phase. The numerical analysis of phase specific mechanical stresses and strains revealed that if the duplex stainless steel is

  9. Color-coded duplex sonography in the study of thyroid pathologic conditions

    International Nuclear Information System (INIS)

    Anguissola, R.; Bozzini, A.; Campani, R.; Bottinelli, O.; Genovese, E.; Guglielmoni, B.; Fulle, I.; Bandi, G.

    1991-01-01

    The authors examined 110 patients with suspected pathologic conditions of the thyroid by means of color-coded duplex US. In addition to the information yielded by conventional US, this technique allows organ vascularization to be demonstrated. Five normal patients were considered as a control group: no tissue vascularization was demonstrated in these cases. In 8 patients presenting with carcinoma or recurrences, vascularization was markedly increased both peripheral and central to the nodule. A few doubts are still to be solved as to the diagnostic value of color-coded duplex US in the evaluation of non-carcinomas nodular pathologic conditions. As a matter of fact, non-functioning avascular adenomas can be demonstrated only in a very low percentage of cases (66%). Color-coded duplex US proved extremely sensitive and specific in depicting malignant neoplasms. Moreover, the use of fine.needle biopsy could be optimized and subsequently reduced. Color-coded duplex US proved to be markedly superior to othe rmethods and techniques in the study of thyroid diseases, especially thyroiditis and multiple pathologic conditions. The simultaneous presence of hypocapture at scintigraphy and peripheral and central vascularization in a single nodule or within multinodular struma at color-Doppler was highly suggestive of malignant thyroid neoplasm. Color-coded duplex US is a low-cost technique, which can be performed on an outpatient basis. Moreover, it is not invasive, nor does it damage the thyroid. That is why its use is almost mandatory in the study of pathologic conditions of the thyroid

  10. Internal Carotid Artery Hypoplasia: Role of Color-Coded Carotid Duplex Sonography.

    Science.gov (United States)

    Chen, Pei-Ya; Liu, Hung-Yu; Lim, Kun-Eng; Lin, Shinn-Kuang

    2015-10-01

    The purpose of this study was to determine the role of color-coded carotid duplex sonography for diagnosis of internal carotid artery hypoplasia. We retrospectively reviewed 25,000 color-coded carotid duplex sonograms in our neurosonographic database to establish more diagnostic criteria for internal carotid artery hypoplasia. A definitive diagnosis of internal carotid artery hypoplasia was made in 9 patients. Diagnostic findings on color-coded carotid duplex imaging include a long segmental small-caliber lumen (52% diameter) with markedly decreased flow (13% flow volume) in the affected internal carotid artery relative to the contralateral side but without intraluminal lesions. Indirect findings included markedly increased total flow volume (an increase of 133%) in both vertebral arteries, antegrade ipsilateral ophthalmic arterial flow, and a reduced vessel diameter with increased flow resistance in the ipsilateral common carotid artery. Ten patients with distal internal carotid artery dissection showed a similar color-coded duplex pattern, but the reductions in the internal and common carotid artery diameters and increase in collateral flow from the vertebral artery were less prominent than those in hypoplasia. The ipsilateral ophthalmic arterial flow was retrograde in 40% of patients with distal internal carotid artery dissection. In addition, thin-section axial and sagittal computed tomograms of the skull base could show the small diameter of the carotid canal in internal carotid artery hypoplasia and help distinguish hypoplasia from distal internal carotid artery dissection. Color-coded carotid duplex sonography provides important clues for establishing a diagnosis of internal carotid artery hypoplasia. A hypoplastic carotid canal can be shown by thin-section axial and sagittal skull base computed tomography to confirm the final diagnosis. © 2015 by the American Institute of Ultrasound in Medicine.

  11. Development of a duplex droplet digital PCR assay for absolute quantitative detection of "Candidatus Liberibacter asiaticus".

    Science.gov (United States)

    Selvaraj, Vijayanandraj; Maheshwari, Yogita; Hajeri, Subhas; Chen, Jianchi; McCollum, Thomas Greg; Yokomi, Raymond

    2018-01-01

    Huanglongbing (HLB, citrus greening) is a devastating citrus disease affecting citrus production worldwide. It is associated with the bacterium "Candidatus Liberibacter asiaticus" (CLas) and is vectored by the Asian citrus psyllid (ACP). Currently, diagnosis of CLas in regulatory samples is based on real-time quantitative polymerase chain reaction (qPCR) using 16S rRNA gene specific primers/probe. The detection of CLas using qPCR is challenging due to low pathogen titer and uneven distribution in infected plants and exacerbated by sampling issues and presence of inhibitors. This study evaluated a duplex droplet digital polymerase chain reaction (ddPCR) using multi-copy gene targets, 16S and RNR, to simultaneously detect CLas DNA targets in the same sample for unambiguous detection of the HLB pathogen in DNA extracts from citrus leaves and ACP. Standard curve analyses on tenfold dilution series with plasmid, citrus leaf and ACP DNA showed that both ddPCR and qPCR exhibited good linearity and efficiency in the duplex assay. CLas-infected low titer samples were used to validate the duplex ddPCR and qPCR performance and demonstrated that detection rate is higher when both 16S and RNR primers were used in duplex assay. However, the receiver operating characteristic analysis indicated that area under the curve for RNR primer was significantly broader, compared to 16S primers for CLas detection at low target titer. The absolute quantification of CLas at variable titers was reproducible and repeatable for both primer sets and the ddPCR showed higher resilience to PCR inhibitors with citrus leaf and ACP extracts. Hence, the resultant duplex ddPCR assay resulted in a significantly improved detection platform for diagnosis of CLas in samples with low pathogen titer.

  12. Molecular architecture: construction of self-assembled organophosphonate duplexes and their electrochemical characterization.

    Science.gov (United States)

    Cattani-Scholz, Anna; Liao, Kung-Ching; Bora, Achyut; Pathak, Anshuma; Hundschell, Christian; Nickel, Bert; Schwartz, Jeffrey; Abstreiter, Gerhard; Tornow, Marc

    2012-05-22

    Self-assembled monolayers of phosphonates (SAMPs) of 11-hydroxyundecylphosphonic acid, 2,6-diphosphonoanthracene, 9,10-diphenyl-2,6-diphosphonoanthracene, and 10,10'-diphosphono-9,9'-bianthracene and a novel self-assembled organophosphonate duplex ensemble were synthesized on nanometer-thick SiO(2)-coated, highly doped silicon electrodes. The duplex ensemble was synthesized by first treating the SAMP prepared from an aromatic diphosphonic acid to form a titanium complex-terminated one; this was followed by addition of a second equivalent of the aromatic diphosphonic acid. SAMP homogeneity, roughness, and thickness were evaluated by AFM; SAMP film thickness and the structural contributions of each unit in the duplex were measured by X-ray reflection (XRR). The duplex was compared with the aliphatic and aromatic monolayer SAMPs to determine the effect of stacking on electrochemical properties; these were measured by impedance spectroscopy using aqueous electrolytes in the frequency range 20 Hz to 100 kHz, and data were analyzed using resistance-capacitance network based equivalent circuits. For the 11-hydroxyundecylphosphonate SAMP, C(SAMP) = 2.6 ± 0.2 μF/cm(2), consistent with its measured layer thickness (ca. 1.1 nm). For the anthracene-based SAMPs, C(SAMP) = 6-10 μF/cm(2), which is attributed primarily to a higher effective dielectric constant for the aromatic moieties (ε = 5-10) compared to the aliphatic one; impedance spectroscopy measured the additional capacitance of the second aromatic monolayer in the duplex (2ndSAMP) to be C(Ti/2ndSAMP) = 6.8 ± 0.7 μF/cm(2), in series with the first.

  13. Bilayer Protograph Codes for Half-Duplex Relay Channels

    Science.gov (United States)

    Divsalar, Dariush; VanNguyen, Thuy; Nosratinia, Aria

    2013-01-01

    re-optimization. The main problem of half-duplex relay coding can be reduced to the simultaneous design of two codes at two rates and two SNRs (signal-to-noise ratios), such that one is a subset of the other. This problem can be addressed by forceful optimization, but a clever method of addressing this problem is via the bilayer lengthened (BL) LDPC structure. This method uses a bilayer Tanner graph to make the two codes while using a concept of "parity forwarding" with subsequent successive decoding that removes the need to directly address the issue of uneven SNRs among the symbols of a given codeword. This method is attractive in that it addresses some of the main issues in the design of relay codes, but it does not by itself give rise to highly structured codes with simple encoding, nor does it give rate-compatible codes. The main contribution of this work is to construct a class of codes that simultaneously possess a bilayer parity- forwarding mechanism, while also benefiting from the properties of protograph codes having an easy encoding, a modular design, and being a rate-compatible code.

  14. Role of magnetic resonance urography in diagnosis of duplex renal system: Our initial experience at a tertiary care institute

    Directory of Open Access Journals (Sweden)

    Milind P Joshi

    2009-01-01

    Full Text Available Aim: To determine diagnostic value of magnetic resonance urography in cases of duplex renal system. Method: Twenty cases between five month to nine years with suspected or known duplex renal system were evaluated by ultrasound (USG, micturating cystourethrography (MCU, intravenous urography (IVU and magnetic resonance urography (MRU. The findings of these diagnostic imaging studies were then compared with each other and against the results of final diagnosis established at surgery. Results: Duplex renal system could be identified in two of these cases on USG, was diagnosed in four in IVU and could be diagnosed in all cases with MRU. Conclusion: MRU is superior and far accurate than IVU, MCU and USG in diagnosing duplex renal system.

  15. Tribological properties of duplex MAO/DLC coatings on magnesium alloy using combined microarc oxidation and filtered cathodic arc deposition

    International Nuclear Information System (INIS)

    Liang Jun; Wang Peng; Hu Litian; Hao Jingcheng

    2007-01-01

    The combined microarc oxidation (MAO) and filtered cathode arc deposition process was used to deposit duplex MAO/DLC coating on AM60B magnesium alloy. The microstructure and composition of the resulting duplex coating were analyzed by Raman spectroscopy, X-ray photoelectron spectroscope (XPS) and scanning electron microscope (SEM). The tribological behaviors of the duplex coating were studied by ball-on-disk friction testing. It is found that the Ti-doped DLC thin film could be successfully deposited onto the polished MAO coating. The duplex MAO/DLC coating exhibits a better tribological property than the DLC or MAO monolayer on Mg alloy substrate, owing to the MAO coating served as an intermediate layer provides improved load support for the soft Mg alloy substrate and the DLC top coating exhibits low friction coefficient

  16. X-Ray diffraction technique applied to study of residual stresses after welding of duplex stainless steel plates

    International Nuclear Information System (INIS)

    Monin, Vladimir Ivanovitch; Assis, Joaquim Teixeira de; Lopes, Ricardo Tadeu; Turibus, Sergio Noleto; Payao Filho, Joao C.

    2014-01-01

    Duplex stainless steel is an example of composite material with approximately equal amounts of austenite and ferrite phases. Difference of physical and mechanical properties of component is additional factor that contributes appearance of residual stresses after welding of duplex steel plates. Measurements of stress distributions in weld region were made by X-ray diffraction method both in ferrite and austenite phases. Duplex Steel plates were joined by GTAW (Gas Tungsten Arc Welding) technology. There were studied longitudinal and transverse stress components in welded butt joint, in heat affected zone (HAZ) and in points of base metal 10 mm from the weld. Residual stresses measured in duplex steel plates jointed by welding are caused by temperature gradients between weld zone and base metal and by difference of thermal expansion coefficients of ferrite and austenite phases. Proposed analytical model allows evaluating of residual stress distribution over the cross section in the weld region. (author)

  17. Passivation of duplex stainless steel in solutions simulating chloride-contaminated concrete

    Directory of Open Access Journals (Sweden)

    Takenouti, H.

    2007-12-01

    Full Text Available Most studies published to date on the corrosion behaviour of stainless reinforcing steel are based on austenitic steel. The market presence of corrugated duplex steel is growing, however. The present study compared passivity in 2205 type duplex and 304 type austenitic stainless steel. Polarization tests in chloride-containing Ca(OH2 solutions confirmed the exceptional performance of duplex steels. X-ray photoelectronic spectroscopy (XPS showed that the passive layer generated on duplex stainless steel in media simulating concrete pore solutions had a higher Cr content than the layer formed on steel in contact with the air. The XPS results also revealed that in duplex steel the form adopted by the passive layer Fe oxides was Fe3O4 in the solutions simulating concrete, rather than Fe2O3, as in duplex steel exposed to air. Electrochemical impedance spectroscopy (EIS can be used to monitor the transformations taking place in the passive layer and analyze the factors involved.La mayoría de los estudios publicados hasta el momento sobre el comportamiento frente a la corrosión de armaduras de acero inoxidable se basan en aceros austeníticos. Sin embargo, la presencia en el mercado de aceros corrugados dúplex es cada vez más importante. En este trabajo se analiza la pasividad de un acero inoxidable dúplex tipo 2205 en comparación con la de un inoxidable austenítico tipo 304. Los ensayos de polarización en disoluciones de Ca(OH2 con cloruros confirman el excepcional comportamiento de los aceros dúplex. La espectroscopía fotoelectrónica de rayos X (XPS informa de que la capa pasiva generada en aceros inoxidables dúplex en medios que simulan la disolución de los poros del hormigón posee mayor contenido en óxidos de Cr que la formada en aire. También se puede deducir de los resultados de XPS que los óxidos de Fe de la capa pasiva de los aceros dúplex se encuentran en forma de Fe3O4 en las disoluciones que simulan el hormigón en vez de en

  18. Detection of 12 respiratory viruses by duplex real time PCR assays in respiratory samples.

    Science.gov (United States)

    Arvia, Rosaria; Corcioli, Fabiana; Ciccone, Nunziata; Della Malva, Nunzia; Azzi, Alberta

    2015-12-01

    Different viruses can be responsible for similar clinical manifestations of respiratory infections. Thus, the etiological diagnosis of respiratory viral diseases requires the detection of a large number of viruses. In this study, 6 duplex real-time PCR assays, using EvaGreen intercalating dye, were developed to detect 12 major viruses responsible for respiratory diseases: influenza A and B viruses, enteroviruses (including enterovirus spp, and rhinovirus spp), respiratory syncytial virus, human metapneumovirus, coronaviruses group I (of which CoV 229E and CoV NL63 are part) and II (including CoV OC43 and CoV HKU1), parainfluenza viruses type 1, 2, 3 and 4, human adenoviruses and human bocaviruses. The 2 target viruses of each duplex reaction were distinguishable by the melting temperatures of their amplicons. The 6 duplex real time PCR assays were applied for diagnostic purpose on 202 respiratory samples from 157 patients. One hundred fifty-seven samples were throat swabs and 45 were bronchoalveolar lavages. The results of the duplex PCR assays were confirmed by comparison with a commercial, validated, assay; in addition, the positive results were confirmed by sequencing. The analytical sensitivity of the duplex PCR assays varied from 10(3) copies/ml to 10(4) copies/ml. For parainfluenza virus 2 only it was 10(5) copies/ml. Seventy clinical samples (35%) from 55 patients (30 children and 25 adults) were positive for 1 or more viruses. In adult patients, influenza A virus was the most frequently detected respiratory virus followed by rhinoviruses. In contrast, respiratory syncytial virus was the most common virus in children, followed by enteroviruses, influenza A virus and coronavirus NL63. The small number of samples/patients does not allow us to draw any epidemiological conclusion. Altogether, the results of this study indicate that the 6 duplex PCR assays described in this study are sensitive, specific and cost-effective. Thus, this assay could be

  19. Development of a Duplex Ultrasound Simulator and Preliminary Validation of Velocity Measurements in Carotid Artery Models.

    Science.gov (United States)

    Zierler, R Eugene; Leotta, Daniel F; Sansom, Kurt; Aliseda, Alberto; Anderson, Mark D; Sheehan, Florence H

    2016-07-01

    Duplex ultrasound scanning with B-mode imaging and both color Doppler and Doppler spectral waveforms is relied upon for diagnosis of vascular pathology and selection of patients for further evaluation and treatment. In most duplex ultrasound applications, classification of disease severity is based primarily on alterations in blood flow velocities, particularly the peak systolic velocity (PSV) obtained from Doppler spectral waveforms. We developed a duplex ultrasound simulator for training and assessment of scanning skills. Duplex ultrasound cases were prepared from 2-dimensional (2D) images of normal and stenotic carotid arteries by reconstructing the common carotid, internal carotid, and external carotid arteries in 3 dimensions and computationally simulating blood flow velocity fields within the lumen. The simulator displays a 2D B-mode image corresponding to transducer position on a mannequin, overlaid by color coding of velocity data. A spectral waveform is generated according to examiner-defined settings (depth and size of the Doppler sample volume, beam steering, Doppler beam angle, and pulse repetition frequency or scale). The accuracy of the simulator was assessed by comparing the PSV measured from the spectral waveforms with the true PSV which was derived from the computational flow model based on the size and location of the sample volume within the artery. Three expert examiners made a total of 36 carotid artery PSV measurements based on the simulated cases. The PSV measured by the examiners deviated from true PSV by 8% ± 5% (N = 36). The deviation in PSV did not differ significantly between artery segments, normal and stenotic arteries, or examiners. To our knowledge, this is the first simulation of duplex ultrasound that can create and display real-time color Doppler images and Doppler spectral waveforms. The results demonstrate that an examiner can measure PSV from the spectral waveforms using the settings on the simulator with a mean absolute error

  20. Estimation of brachial artery volume flow by duplex ultrasound imaging predicts dialysis access maturation.

    Science.gov (United States)

    Ko, Sae Hee; Bandyk, Dennis F; Hodgkiss-Harlow, Kelley D; Barleben, Andrew; Lane, John

    2015-06-01

    This study validated duplex ultrasound measurement of brachial artery volume flow (VF) as predictor of dialysis access flow maturation and successful hemodialysis. Duplex ultrasound was used to image upper extremity dialysis access anatomy and estimate access VF within 1 to 2 weeks of the procedure. Correlation of brachial artery VF with dialysis access conduit VF was performed using a standardized duplex testing protocol in 75 patients. The hemodynamic data were used to develop brachial artery flow velocity criteria (peak systolic velocity and end-diastolic velocity) predictive of three VF categories: low (800 mL/min). Brachial artery VF was then measured in 148 patients after a primary (n = 86) or revised (n = 62) upper extremity dialysis access procedure, and the VF category correlated with access maturation or need for revision before hemodialysis usage. Access maturation was conferred when brachial artery VF was >600 mL/min and conduit imaging indicated successful cannulation based on anatomic criteria of conduit diameter >5 mm and skin depth 800 mL/min was predicted when the brachial artery lumen diameter was >4.5 mm, peak systolic velocity was >150 cm/s, and the diastolic-to-systolic velocity ratio was >0.4. Brachial artery velocity spectra indicating VF 800 mL/min. Duplex testing to estimate brachial artery VF and assess the conduit for ease of cannulation can be performed in 5 minutes during the initial postoperative vascular clinic evaluation. Estimation of brachial artery VF using the duplex ultrasound, termed the "Fast, 5-min Dialysis Duplex Scan," facilitates patient evaluation after new or revised upper extremity dialysis access procedures. Brachial artery VF correlates with access VF measurements and has the advantage of being easier to perform and applicable for forearm and also arm dialysis access. When brachial artery velocity spectra criteria confirm a VF >800 mL/min, flow maturation and successful hemodialysis are predicted if anatomic criteria

  1. Study on the wear of TiN/Ti duplex and multilayer coatings in microabrasion tests

    International Nuclear Information System (INIS)

    Flores, M; De Las Heras, E; Ruelas, R; Rodriguez, E; Bautista, A; Pazos, L; Corengia, P

    2008-01-01

    Ionic nitriding, on steels, is used to harden the surface of components improving resistance to corrosion and wear and increasing the stress life. Duplex treatments are an alternative for resolving the limitations of very hard coatings on less hard substrates. In this case the duplex treatment consists of an ionic nitriding treatment followed by a single or multilayer coatings deposited by means of the PVD technique. This work presents the influence of the variation in the severity of contact on the kind of wear present in the microabrasion test used to measure the wear coefficient of duplex coatings, consisting of a layer nitrided by DC-pulsed plasma plus TiN coatings and multilayers of TiN/Ti deposited on non-nitrided and nitrided AISI 316L stainless steel and H13 steel. The severity of contact was modified by varying the charge (0.25 to 1 N). The abrasives used were a suspension of 0.1μm diameter diamond particles and a suspension of an average 5 μm diameter aluminum particles. The influence of the presence of relatively soft metallic layers on the determination of the wear coefficient was analyzed in the metal-ceramic multilayers. Two sphere revolving speeds of de 0.05 and 0.154 m/s were used on two microabrasion machines: one commercial and the other built in the UdeG laboratory. The wear marks were photographed and measured with an optic microscope. The value of the critical charge at which the transition occurs between the methods of wear of the substrates and the nitrited samples was determined. Resistance to the AISI 316L steel's microabrasive wear increases with the ionic nitriding treatment. The duplex coatings increase resistance to the wear from the nitrited samples. The wear resistance of the samples with multilayer coatings surpassed that of the duplex samples with multilayer coatings. The greater resistance of the multilayers may be explained by an increase in the resistance to the fracture and not by a increase in surface hardness. The transition

  2. Study of corrosive effect of oil in super duplex stainless steels; Estudo do efeito corrosivo do petroleo em acos super duplex

    Energy Technology Data Exchange (ETDEWEB)

    Gusmao, E.F.; Azambuja, V.M. [IFES, Coordenadoria de Metalurgia, Vitoria, ES (Brazil); Santos, D.S. [Universidade Federal do Rio de Janeiro (PEMM/COPPE/UFRJ), RJ (Brazil). Pos-Graduacao em Engenharia Metalurgica e de Materiais

    2010-07-01

    The super duplex stainless steel was exposed in an environment at 75 degree C with oil for days, weeks and month to observe the change in mass. The corrosion leads to loss of weight of material which could harm the economy of a company, as this will have to stop production to replace the corroded part. Hence the great importance of studies on ways to mitigate the corrosion. There was a chemical attack by the reagent Behara and testing to study the quality of the protective coating after the tests with oil by electrochemical impedance. (author)

  3. Electroless Ni-P/Ni-B duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance

    International Nuclear Information System (INIS)

    Narayanan, T.S.N. Sankara; Krishnaveni, K.; Seshadri, S.K.

    2003-01-01

    The present work deals with the formation of Ni-P/Ni-B duplex coatings by electroless plating process and evaluation of their hardness, wear resistance and corrosion resistance. The Ni-P/Ni-B duplex coatings were prepared using dual baths (acidic hypophosphite- and alkaline borohydride-reduced electroless nickel baths) with both Ni-P and Ni-B as inner layers and with varying single layer thickness. Scanning electron microscopy (SEM) was used to assess the duplex interface. The microhardness, wear resistance and corrosion resistance of electroless nickel duplex coatings were compared with electroless Ni-P and Ni-B coatings of similar thickness. The study reveals that the Ni-P and Ni-B coatings are amorphous in their as-plated condition and upon heat-treatment at 450 deg. C for 1 h, both Ni-P and Ni-B coatings crystallize and produce nickel, nickel phosphide and nickel borides in the respective coatings. All the three phases are formed when Ni-P/Ni-B and Ni-B/Ni-P duplex coatings are heat-treated at 450 deg. C for 1 h. The duplex coatings are uniform and the compatibility between the layers is good. The microhardness, wear resistance and corrosion resistance of the duplex coating is higher than Ni-P and Ni-B coatings of similar thickness. Among the two types of duplex coatings studied, hardness and wear resistance is higher for coatings having Ni-B coating as the outer layer whereas better corrosion resistance is offered by coatings having Ni-P coating as the outer layer

  4. Development and properties of duplex MgF2/PCL coatings on biodegradable magnesium alloy for biomedical applications.

    Science.gov (United States)

    Makkar, Preeti; Kang, Hoe Jin; Padalhin, Andrew R; Park, Ihho; Moon, Byoung-Gi; Lee, Byong Taek

    2018-01-01

    The present work addresses the performance of polycaprolactone (PCL) coating on fluoride treated (MgF2) biodegradable ZK60 magnesium alloy (Mg) for biomedical application. MgF2 conversion layer was first produced by immersing Mg alloy substrate in hydrofluoric acid solution. The outer PCL coating was then prepared using dip coating technique. Morphology, elements profile, phase structure, roughness, mechanical properties, invitro corrosion, and biocompatibility of duplex MgF2/PCL coating were then characterized and compared to those of fluoride coated and uncoated Mg samples. The invivo degradation behavior and biocompatibility of duplex MgF2/PCL coating with respect to ZK60 Mg alloy were also studied using rabbit model for 2 weeks. SEM and TEM analysis showed that the duplex coating was uniform and comprised of porous PCL film (~3.3 μm) as upper layer with compact MgF2 (~2.2 μm) as inner layer. No significant change in microhardness was found on duplex coating compared with uncoated ZK60 Mg alloy. The duplex coating showed improved invitro corrosion resistance than single layered MgF2 or uncoated alloy samples. The duplex coating also resulted in better cell viability, cell adhesion, and cell proliferation compared to fluoride coated or uncoated alloy. Preliminary invivo studies indicated that duplex MgF2/PCL coating reduced the degradation rate of ZK60 Mg alloy and exhibited good biocompatibility. These results suggested that duplex MgF2/PCL coating on magnesium alloy might have great potential for orthopedic applications.

  5. Duplex-assisted carotid artery stenting without administration of contrast medium for patients with chronic kidney disease or allergic reaction.

    Science.gov (United States)

    Mizowaki, Takashi; Fujita, Atsushi; Imahori, Taichiro; Uyama, Atsushi; Inoue, Satoshi; Kohta, Masaaki; Hamaguchi, Hirotoshi; Sasayama, Takashi; Hosoda, Kohkichi; Kohmura, Eiji

    2016-07-01

    We aimed to investigate the safety and feasibility of duplex-assisted carotid artery stenting (CAS) without administration of contrast medium for the prevention of adverse reactions. Fifteen patients (9 % of all CASs) with severe carotid stenosis (≥70 %) associated with chronic kidney disease (CKD) (stage ≥3) or allergy to contrast medium underwent duplex-assisted CAS without administration of contrast medium over 4 years. The procedural success rate and perioperative complication rates were compared between the duplex-assisted CAS (n = 15) and conventional CAS (n = 153) groups. The technical success rate was 100 % in both groups. Combined stroke or death rates during the post-procedural period did not differ significantly between the duplex-assisted CAS group (0/15, 0 %) and conventional CAS group (4/153, 2.6 %). None of the 14 patients with CKD in the duplex-assisted CAS group experienced further deterioration of renal function. The mean surface radiation dose of participants in the duplex-assisted CAS group (n = 13, 312 ± 131 mGy) was significantly lower than that of the conventional CAS group (n = 31, 1036 ± 571 mGy) (p duplex-assisted CAS group (156 ± 39.7 min) and the conventional CAS group (156 ± 37.4 min). Duplex-assisted CAS without administration of contrast medium could be an alternative option in selected patients deemed to be at high risk for renal failure from nephrotoxic contrast medium or who have an allergy to contrast medium.

  6. Law of mixture used to model the flow behavior of a duplex stainless steel at high temperatures

    International Nuclear Information System (INIS)

    Momeni, A.; Dehghani, K.; Poletti, M.C.

    2013-01-01

    In this investigation the flow curves of a duplex stainless steel were drawn by performing hot compression tests over a wide temperature range of 950–1200 °C and strain rates of 0.001–100 s −1 . The flow curves of ferrite and austenite phases in the duplex structure were depicted by conducting similar hot compression tests on two steels that were cast and prepared with the same chemical compositions. The flow curves of the austenitic steel were found typical of dynamic recrystallization. They were successfully modeled by using the experimental exponential equation proposed by Cingara and McQueen. The flow curves of the ferritic steel were typical of dynamic recovery. They were modeled by the dislocation density evolution function proposed by Estrin and Meckning. Comparing the flow curves of three studied steels, it was found that the flow curves of the duplex steel were very similar and close to those of the ferrite steel. It was understood that in a duplex structure of ferrite and austenite the flow behavior is mostly controlled by the softer phase, i.e. ferrite. The law of mixture was modified to consider the strain partitioning between ferrite and austenite. The distribution coefficients of ferrite and austenite were described and determined at different deformation conditions. The results of modeling satisfactorily predicted the experimental curves. It was shown that the influence of austenite on the flow behavior of the duplex structure is almost low. However, it increases as strain rate or temperature rises. - Highlights: ► Flow curves of austenite and ferrite in the duplex steel were modeled separately. ► The flow behavior of the duplex steel is mostly controlled by ferrite. ► The effect of austenite on flow curve increases with temperature and strain rate. ► The flow curve of the duplex steel is modeled by the modified law of mixture

  7. Three-dimensional shuffling of horses in a strike-slip duplex: an example from the Lambertville sill, New Jersey

    Science.gov (United States)

    Laney, Stephen E.; Gates, Alexander E.

    1996-06-01

    Detailed analysis of a dextral strike-slip duplex within the relatively isotropic rocks of the Lambertville sill, New Jersey indicates that horses have experienced vertical, horizontal and oblique movements resulting from extrusional shuffling within a restraining bend. This is the first documentation of the three-dimensional movement of horses within a strike-slip duplex. Deformation within the duplex shows a complex system of early synthetic fractures and reverse faults followed by antithetic fractures which dissect previously continuous slab-shaped horses into diamond-shaped lenses. Most faults are oblique slip. Antithetic fault movements and clockwise rigid rotation of horses dominate the south half of the duplex and synthetic movements and counterclockwise rotations dominate the north half. Slickenline plunges on curved horse-bounding fault surfaces within the duplex range from nearly horizontal to 40° resulting in both lateral movements (middle) to normal movements (tails) on a single horse. Curved slickensides commonly have opposite senses of movement on either side of individual horses indicating relative emergence or submergence. Such a geometry could also result from a group of horses moving in the same oblique direction but at different rates. These complex extrusional-type movements were observed in both cross-sectional and plan views. The net result of the movements is a contraction or flattening of the duplex normal to the bounding faults. The horses shifted to accommodate this flattening as overall displacement was transferred between the bounding faults along curved internal faults.

  8. NMR and molecular modeling evidence for a G·A mismatch base pair in a purine-rich DNA duplex

    International Nuclear Information System (INIS)

    Li, Ying; Wilson, W.D.; Zon, G.

    1991-01-01

    1 H NMR experiments indicate that the oligomer 5'-d(ATGAGCGAATA) forms an unusual 10-base-pair duplex with 4 G·A base pairs and a 3' unpaired adenosine. NMR results indicate that guanoxine imino protons of the F·A mismatches are not hydrogen bonded but are stacked in the helix. A G→ I substitution in either G·A base pair causes a dramatic decrtease in duplex stability and indicates that hydrogen bonding of the guanosine amino group is critical. Nuclear Overhauser effect spectroscopy (NOESY) and two-dimensional correlated spectroscopy (COSY) results indicate that the overall duplex conformation is in the B-family. Cross-strand NOEs in two-dimensional NOESY spectra between a mismatched AH2 and an AH1' of the other mismatched base pair and between a mismatched GH8 and GNH1 of the other mismatch establish a purine-purine stacking pattern, adenosine over adenosine and guanosine over guanosine, which strongly stabilizes the duplex. A computer graphics molecular model of the ususual duplex was constructed with G·A base pairs containing A-NH 2 to GN3 and G-NH 2 to AN7 hydrogen bonds and B-form base pairs on both sides of the G·A pairs [5'-d(ATGAGC)]. The energy-minimized duplex satisfies all experimental constraints from NOESY and COSY results. A hydrogen bond from G-NH 2 of the mismatch to a phosphate oxygen is predicted

  9. A duplex DNA-gold nanoparticle probe composed as a colorimetric biosensor for sequence-specific DNA-binding proteins.

    Science.gov (United States)

    Ahn, Junho; Choi, Yeonweon; Lee, Ae-Ree; Lee, Joon-Hwa; Jung, Jong Hwa

    2016-03-21

    Using duplex DNA-AuNP aggregates, a sequence-specific DNA-binding protein, SQUAMOSA Promoter-binding-Like protein 12 (SPL-12), was directly determined by SPL-12-duplex DNA interaction-based colorimetric actions of DNA-Au assemblies. In order to prepare duplex DNA-Au aggregates, thiol-modified DNA 1 and DNA 2 were attached onto the surface of AuNPs, respectively, by the salt-aging method and then the DNA-attached AuNPs were mixed. Duplex-DNA-Au aggregates having the average size of 160 nm diameter and the maximum absorption at 529 nm were able to recognize SPL-12 and reached the equivalent state by the addition of ∼30 equivalents of SPL-12 accompanying a color change from red to blue with a red shift of the maximum absorption at 570 nm. As a result, the aggregation size grew to about 247 nm. Also, at higher temperatures of the mixture of duplex-DNA-Au aggregate solution and SPL-12, the equivalent state was reached rapidly. On the contrary, in the control experiment using Bovine Serum Albumin (BSA), no absorption band shift of duplex-DNA-Au aggregates was observed.

  10. An Optimal Analysis in Wireless Powered Full-duplex Relaying Network

    Directory of Open Access Journals (Sweden)

    K.-T. Nguyen

    2017-04-01

    Full Text Available Wireless-powered cellular networks (WPCNs are currently being investigated to exploit the reliability and improve battery lifetime of mobile users. This paper investigates the energy harvesting structure of the full-duplex relaying networks. By using the time switching based relaying (TSR protocol and Amplify-and-Forward (AF model in delay-limited transmission scheme, we propose the closed-form expression of the outage probability and then calculate the optimal throughput. An important result can be taken obviously that the time fraction in TSR, the position of relay, the noise as well as the energy conversation impacting on the outage probability as well as the optimal throughput. By Monte Carlo simulation, the numerical results indicate an effective relaying strategy in full-duplex cooperative systems. Finally, we provide fundamental design guidelines for selecting time fraction in TSR that satisfies the requirements of a practical relaying system.

  11. Fracture mechanics evaluation of cast duplex stainless steel after thermal aging

    International Nuclear Information System (INIS)

    Tujikura, Y.; Urata, S.

    1999-01-01

    For the primary coolant piping of PWRs in Japan, cast duplex stainless steel, which is excellent in terms of strength, corrosion resistance and weldability, has conventionally been used. Cast duplex stainless steel contains the ferrite phase in the austenite matrix, and thermal aging after long-term service is known to decrease fracture toughness. Therefore, we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secure, even when such through-wall crack length is assumed to be as large as the fatigue crack length grown for a service period of up to 60 years. (orig.)

  12. Fracture mechanics evaluation of cast duplex stainless steel after thermal aging

    Energy Technology Data Exchange (ETDEWEB)

    Tujikura, Y.; Urata, S. [Kansai Electr. Power Co., Inc., Osaka (Japan). General Office of Nucl. and Fossil Power Production

    1999-07-01

    For the primary coolant piping of PWRs in Japan, cast duplex stainless steel, which is excellent in terms of strength, corrosion resistance and weldability, has conventionally been used. Cast duplex stainless steel contains the ferrite phase in the austenite matrix, and thermal aging after long-term service is known to decrease fracture toughness. Therefore, we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secure, even when such through-wall crack length is assumed to be as large as the fatigue crack length grown for a service period of up to 60 years. (orig.)

  13. Fracture mechanics evaluation for the cast duplex stainless steel after thermal aging

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Shigeru [Kansai Electric Power Co., Inc., Osaka (Japan)

    1998-12-31

    For the primary coolant piping of PWRs in Japan, cast duplex stainless steel which is excellent in terms of strength, corrosion resistance, and weldability has conventionally been used. The cast duplex stainless steel contains the ferrite phase in the austenite matrix and thermal aging after long term service is known to change its material characteristics. It is considered appropriate to apply the methodology of elastic plastic fracture mechanics for an evaluation of the integrity of the primary coolant piping after thermal aging. Therefore, we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secured, even when such through wall crack length is assumed to equal the fatigue crack growth length for a service period of up to 60 years. (author)

  14. Providing Fast Discovery in D2D Communication with Full Duplex Technology

    DEFF Research Database (Denmark)

    Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

    2016-01-01

    technology to provide D2D fast discovery. Such framework provides an algorithm to estimate the number of neighbor devices and to dynamically decide the transmission probability, for adapting to network changes and meeting the 10 milliseconds target. Finally, a signaling scheme is proposed to reduce......In Direct Device-to-Device (D2D), the device awareness procedure known as the discovery phase is required prior to the exchange of data. This work considers autonomous devices where the infrastructure is not involved in the discovery procedure. Commonly, the transmission of the discovery message...... the network interference. Results show that our framework performs better than a static approach, reducing the time it takes to complete the discovery phase. In addition, supporting full duplex allows to further reduce the discovery time compared to half duplex transmission mode....

  15. Effect of solution treatment on microstructure and properties of duplex stainless steel

    Science.gov (United States)

    Wang, X. Y.; Luo, J. M.; Huang, L. Q.; Wang, H. B.; Ma, C. W.

    2017-09-01

    The influence of solution treatment on microstructure and properties of 2205 duplex stainless steel (DSS) was studied. The microstructure, precipitates and corrosion resisting property were observed and analyzed by means of optical microscopy (OM), scanning electron microscopy (SEM) and electrochemical methods. The results showed that a large number of brittle σ-phase precipitates, which deteriorate the plasticity and corrosion resistance of the material, were easy to produce in the duplex stainless steel under the low temperature. The precipitation of σ-phase can be decreased and the plasticity and corrosion resistance can be improved by increasing solution temperature. In addition, the ferrite content increases with the increase of solution temperature, while less affected by cooling rate.

  16. Spinodal decomposition mechanism study on the duplex stainless steel UNS S31803 using ultrasonic speed measurements

    International Nuclear Information System (INIS)

    Albuquerque, Victor Hugo C. de; Macedo Silva, Edgard de; Pereira Leite, Josinaldo; Pindo de Moura, Elineudo; Araujo Freitas, Vera Lucia de; Tavares, Joao Manuel R.S.

    2010-01-01

    This work, focuses on the spinodal decomposition mechanism study on the duplex stainless steel duplex UNS S31803, composed by austenite (γ) and ferrite (α) phases, at 425 o C and 475 o C temperatures by ultrasonic speed measurements. This temperature range is responsible for the transformation mechanism of α initial phase to α phases (poor in chromium) and α' (rich in chromium) by spinodal decomposition. The techniques to accomplish this analysis are based mainly on X-ray diffraction measures and ultrasonic speed. The obtained results show that it is possible to conclude that the use of ultrasonic speed measurements indicates a promising technique for following-up the phase transformation and spinodal decomposition on the steel studied.

  17. Error rates of a full-duplex system over EGK fading channels subject to laplacian interference

    KAUST Repository

    Soury, Hamza

    2017-07-31

    This paper develops a mathematical paradigm to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). Particularly, we study the dominant intra-cell interferer problem that appears between HD users scheduled on the same FD-channel. The distribution of the dominant interference is first characterized via its distribution function, which is derived in closed-form. Assuming Nakagami-m fading, the probability of error for different modulation schemes is studied and a unified closed-form expression for the average symbol error rate is derived. To this end, we show the effective downlink throughput gain, harvested by employing FD communication at a BS that serves HD users, as a function of the signal-to-interference-ratio when compared to an idealized HD interference and noise free BS operation.

  18. Characterization by X ray diffraction of deleterious phases precipitated in a super duplex stainless steel

    International Nuclear Information System (INIS)

    Pardal, Juan M.; Tavares, Sergio S. Maior; Fonseca, Maria P. Cindra; Montenegro, Talles Ribeiro; Dias, Antonio Jose N.; Almeida, Sergio L. de

    2010-01-01

    In this work the identification and quantification of deleterious phases in two super duplex stainless steels grade UNS S32750, with quite different grain sizes, was performed by X-ray diffraction. The materials were isothermally aged in the 800 . 950 deg C range. Direct comparison method was used to quantify the ferrite phase in each sample. The amount of deleterious phases (σ, χ and γ2) formed was calculated by the difference of the amount of ferrite phase measured in each specimen to the amount of ferrite initially measured in the un-aged steel. The results obtained give an useful contribution to the understanding of kinetics of deleterious phases precipitation in super duplex steels. (author)

  19. Giant hydronephrosis in a case of ureterocele with duplex system: an entity yet not reported.

    Science.gov (United States)

    Aeron, Ruchir; Sokhal, Ashok Kumar; Kumar, Manoj; Sankhwar, Satyanarayan

    2017-08-10

    Ureterocele, which is a cystic dilatation of the terminal ureter, is usually associated with the upper moiety in a case of the duplex system. Giant hydronephrosis, a rare entity, is usually due to pelviureteric junction obstruction and is usually diagnosed in infants and children. We report a unique case of a unilateral complete duplex system with ureterocele with giant hydronephrosis of the upper moiety in an adult woman presenting as an abdominal lump. To the best of our knowledge, this is the first case of giant hydronephrosis associated with ureterocele in an adult patient. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. 99Tcm-DTPA renography in evaluating the function of duplex kidneys in pediatric patients

    International Nuclear Information System (INIS)

    Zhang Lixia; Wang Xiaoming; Chen Jinyan; Su Junmei

    2013-01-01

    Objective: To study the value of 99 Tc m -DTPA dynamic renography in evaluating the function of duplex kidneys in pediatric patients. Methods: Twenty-five pediatric patients with duplex kidneys diagnosed by ultrasound or MR urography (MRU) were included (9 males, 16 females; mean age:(23.80 ± 20.97) months, range: 2-72 months). Twenty patients (9 males,11 females; mean age: (32.95 ± 23.58) months, range: 2-72 months) with urinary tract infection but without duplex kidneys confirmed by ultrasound or MRU were chosen as control group during the same period of this study. All patients and controls were divided into two subgroups according to their ages (group Ⅰ, 0-24 months; group Ⅱ, 25-72 months). The research was approved by the ethics committee, and all patients' parents (or guardians) signed informed consents. The time-activity curve was generated on the dynamic imaging data automatically with GFR calculated. The uptake rates of the upper and lower moieties were measured by drawing the corresponding ROIs in the duplex kidney. Dunnett-t test was used for statistical analysis. Results: There were 25 patients with 26 duplex kidneys (1 case bilateral), 16 on the left and 10 on the right. The time-activity curve of 6 cases was normal, 9 with continuously upward type, 4 with high level plateau type, 2 with parabolic type and 5 with low level plateau type. There were 19 abnormal kidneys in group Ⅰ and 7 in group Ⅱ, and 20 kidneys in each control subgroup. The GFR of patients with normal renography was (78.81 ± 15.97) ml/min (group Ⅰ) and (64.68 ± 11.15) ml/min (group Ⅱ), continuously upward type was (72.11 ±22.76) ml/min (group Ⅰ) and (63.41 ± 16.42) ml/min (group Ⅱ), high level plateau and parabolic types were (68.74 ± 16.17) ml/min and (65.26 ± 15.27) ml/min in group Ⅰ, respectively. There was no statistically significant difference between the GFR of different renography type groups and that of the controls (group Ⅰ: (79.35 ±13.31) ml

  1. Corrosion studies of austenitic and duplex stainless steels in aqueous lithium bromide solution at different temperatures

    International Nuclear Information System (INIS)

    Igual Munoz, A.; Garcia Anton, J.; Lopez Nuevalos, S.; Guinon, J.L.; Perez Herranz, V.

    2004-01-01

    The corrosion behavior of three stainless steels EN 14311, EN 14429 (austenitic stainless steels) and EN 14462 (duplex stainless steel) was studied in a commercial LiBr solution (850 g/l LiBr solution containing chromate as inhibitor) at different temperatures (25, 50, 75 and 85 deg C) by electrochemical methods. Open circuit potentials shifted towards more active values as temperature increased, while corrosion potentials presented the opposite tendency. The most resistant alloys to general corrosion were EN 14429 and EN 14462 because they had the lowest corrosion current for all temperatures. In all the cases corrosion current increases with temperature. Pitting corrosion resistance is improved by the EN 14462, which presented the highest pitting potential, and the lowest passivation current for the whole range of temperatures studied. The duplex alloy also presents the worst repassivation behavior (in terms of the narrowest difference between corrosion potential and pitting potential); it does not repassivate from 50 deg C

  2. A full-duplex working integrated optoelectronic device for optical interconnect

    Science.gov (United States)

    Liu, Kai; Fan, Huize; Huang, Yongqing; Duan, Xiaofeng; Wang, Qi; Ren, Xiaomin; Wei, Qi; Cai, Shiwei

    2018-05-01

    In this paper, a full-duplex working integrated optoelectronic device is proposed. It is constructed by integrating a vertical cavity surface emitting laser (VCSEL) unit above a resonant cavity enhanced photodetector (RCE-PD) unit. Analysis shows that, the VCSEL unit has a threshold current of 1 mA and a slop efficiency of 0.66 W/A at 849.7 nm, the RCE-PD unit obtains its maximal absorption quantum efficiency of 90.24% at 811 nm with a FWHM of 4 nm. Moreover, the two units of the proposed integrated device can work independently from each other. So that the proposed integrated optoelectronic device can work full-duplex. It can be applied for single fiber bidirectional optical interconnects system.

  3. Prenatal complicated duplex collecting system and ureterocele-Important risk factors for urinary tract infection.

    Science.gov (United States)

    Visuri, Sofia; Jahnukainen, Timo; Taskinen, Seppo

    2018-04-01

    To evaluate the risk of urinary tract infections (UTIs) in infants with prenatally detected complicated duplex collecting system (CDS) or ureterocele. All patients with prenatally detected CDS (n=34) or single system ureterocele (n=7) who were admitted to our institution between 2003 and 2013 were enrolled in this retrospective analysis. Duplex collecting systems with ureterocele (n=13), vesicoureteral reflux (VUR) (n=20) or nonrefluxing megaureter without ureterocele (n=7) were determined as complicated. Twenty-six (63%) patients were females. The prevalence of UTI was compared to 66 controls. The median follow-up time was 5.5 (1.7-12.2) years. Eighteen (44%) patients and 3 (5%) controls had at least one UTI (pduplex collecting system associated with nonrefluxing megaureter are at high risk of UTI despite prophylactic antibiotics. In case of prenatally detected ureterocele we suggest to consider early endoscopic perforation. III. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Progress Towards the Development of a Long-Lived Venus Lander Duplex System

    Science.gov (United States)

    Dyson, Rodger, W.; Bruder, Geoffrey A.

    2011-01-01

    NASA has begun the development of a combined Stirling cycle power and cooling system (duplex) to enable the long-lived surface exploration of Venus and other harsh environments in the solar system. The duplex system will operate from the heat provided by decaying radioisotope plutonium-238 or its substitute. Since the surface of Venus has a thick, hot, and corrosive atmosphere, it is a challenging proposition to maintain sensitive lander electronics under survivable conditions. This development effort requires the integration of: a radioisotope or fission heat source; heat pipes; high-temperature, corrosion-resistant material; multistage cooling; a novel free-displacer Stirling convertor for the lander; and a minimal vibration thermoacoustic Stirling convertor for the seismometer. The first year effort includes conceptual system design and control studies, materials development, and prototype hardware testing. A summary of these findings and test results is presented in this report.

  5. Results of post-laparoscopic cholecystectomy duplex scan without deep vein thrombosis prophylaxis prior to surgery

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Pakaneh

    2012-11-01

    Full Text Available  Abstract Backgrounds: There are controversies among surgeons about prophylaxis of deep vein thrombosis (DVT in laparoscopic cholecystectomy. The aim of this study was the assessment of patients’ condition after laparoscopic cholecystectomy without any prophylactic measure. Methods: 100 cases of laparoscopic cholecystectomy without DVT prophylaxis were followed by duplex scanning in the first postoperative day and by physical examination and patient history at the first to second postoperative week however no clinical sign was found for DVT. Results: Only one case of partially thrombosis (1% was found by duplex scanning which was managed conservatively. Conclusion: Laparoscopic cholecystectomy may consider as a low-risk procedure and routine prophylaxis may not be justified in the absence of other risk factor. 

  6. Alternate transmission with half-duplex relaying in MIMO interference relay networks

    KAUST Repository

    Park, Seongho

    2013-12-01

    In this paper, we consider an alternate transmission scheme for a multiple-input multiple-output interference relay channel where multiple sources transmit their own signals to their corresponding destinations via one of two relaying groups alternately every time phase. Each of the relaying groups has arbitrary number of relays, and each relay operates in half-duplex amplify-and-forward mode. In our scheme, the received signals at the relay nodes consist of desired signals and two different interference signals such as the inter-source interferences and the inter-group interferences which are caused by the phase incoherence of relaying. As such, we propose an iterative interference alignment algorithm to mitigate the interferences. We show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying system in the interference relay channels. © 2013 IEEE.

  7. The Mechanical Behavior of a 25Cr Super Duplex Stainless Steel at Elevated Temperature

    Science.gov (United States)

    Lasebikan, B. A.; Akisanya, A. R.; Deans, W. F.

    2013-02-01

    Super duplex stainless steel (SDSS) is a candidate material for production tubing in oil and gas wells and subsea pipelines used to transport corrosive hydrocarbon fluids. The suitability of this material for high temperature applications is examined in this article. The uniaxial tensile properties are determined for a 25Cr SDSS over a range of temperature relevant to high pressure-high temperature oil and gas wells. It is shown that there is a significant effect of temperature on the uniaxial tensile properties. Elevated temperature was shown to reduce the Young's modulus and increase the strain hardening index; temperature effects on these two parameters are usually neglected in the design of subsea pipelines and oil well tubulars, and this could lead to wrong predictions of the collapse pressure. The manufacturing process of the super duplex tubular did not lead to significant anisotropy in the hardness and the ultimate tensile and uniaxial yield strengths.

  8. Microstructure and mechanical properties of friction stir welded SAF 2507 super duplex stainless steel

    International Nuclear Information System (INIS)

    Sato, Y.S.; Nelson, T.W.; Sterling, C.J.; Steel, R.J.; Pettersson, C.-O.

    2005-01-01

    The microstructure and mechanical properties of friction stir (FS) welded SAF 2507 super duplex stainless steel were examined. High-quality, full-penetration welds were successfully produced in the super duplex stainless steel by friction stir welding (FSW) using polycrystalline cubic boron nitride (PCBN) tool. The base material had a microstructure consisting of the ferrite matrix with austenite islands, but FSW refined grains of the ferrite and austenite phases in the stir zone through dynamic recrystallisation. Ferrite content was held between 50 and 60% throughout the weld. The smaller grain sizes of the ferrite and austenite phases caused increase in hardness and strength within the stir zone. Welded transverse tensile specimen failed near the border between the stir zone and TMAZ at the retreating side as the weld had roughly the same strengths as the base material

  9. Eddy Current Transducer Dedicated for Sigma Phase Evaluation in Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Grzegorz Psuj

    2012-01-01

    Full Text Available The paper describes a new transducer dedicated for evaluation of a duplex stainless steel (DSS. Different phases which exist in DSS have influence on mechanical as well as on electrical properties. Therefore, an eddy current transducer was utilized. In order to achieve high sensitivity, a differential type of the transducer was selected. The performance of the transducer was verified by utilizing the samples which had a different amount of sigma phase.

  10. Hybrid recursive active filters for duplexing in RF transmitter front-ends

    Science.gov (United States)

    Gottardo, Giuseppe; Donati, Giovanni; Musolff, Christian; Fischer, Georg; Felgentreff, Tilman

    2016-08-01

    Duplex filters in modern base transceiver stations shape the channel in order to perform common frequency division duplex operations. Usually, they are designed as cavity filters, which are expensive and have large dimensions. Thanks to the emerging digital technology and fast digital converters, it is possible to transfer the efforts of designing analog duplex filters into digital numeric algorithms applied to feedback structures, operating on power. This solution provides the shaping of the signal spectrum directly at the output of the radio frequency (RF) power amplifiers (PAs) relaxing the transmitter design especially in the duplexer and in the antenna sections. The design of a digital baseband feedback applied to the analog power RF amplifiers (hybrid filter) is presented and verified by measurements. A model to describe the hybrid system is investigated, and the relation between phase and resonance peaks of the resulting periodic band-pass transfer function is described. The stability condition of the system is analyzed using Nyquist criterion. A solution involving a number of digital feedback and forward branches is investigated defining the parameters of the recursive structure. This solution allows the closed loop system to show a periodic band pass with up to 500 kHz bandwidth at the output of the RF amplifier. The band-pass magnitude reaches up to 17 dB selectivity. The rejection of the PA noise in the out-of-band frequencies is verified by measurements. The filter is tested with a modulated LTE (Long Term Evolution) signal showing an ACPR (Adjacent Channel Power Ratio) enhancement of 10 dB of the transmitted signal.

  11. Interference Management in Full-Duplex Cellular Networks with Partial Spectrum Overlap

    KAUST Repository

    Randrianantenaina, Itsikiantsoa

    2017-03-31

    Full-duplex (FD) communication is promoted to double the spectral efficiency when compared to the halfduplex (HD) counterpart. In the context of cellular networks, however, FD communication exacerbates the aggregate uplink and downlink interference, which diminishes the foreseen FD gains. This paper considers a flexible duplex system, denoted by -duplex (-D) system, wherein a fine-grained bandwidth control for each uplink/downlink channel pair in each base station (BS) is allowed, which also leads to partial spectrum overlap between the uplink and downlink channels. The paper addresses the resulting interference management problem by maximizing a network-wide rate-based utility function subject to uplink/downlink power constraints, so as to determine userto- BS association, user-to-channel scheduling, the UL and DL transmit powers, and the fraction of spectrum overlap between UL and DL for every user, under the assumption that the number of available channels and users are equal. The paper solves such a non-convex mixed-integer optimization problem in an iterative way by decoupling the problem into several subproblems. Particularly, the user-to-BS association problem is solved using a matching algorithm that is a generalization of the stable marriage problem. The scheduling problem is solved by iterative Hungarian algorithm. The power and spectrum overlap problem is solved by successive convex approximation. The proposed iterative strategy guarantees an efficient one-toone user to BS and channel assignment. It further provides optimized flexible duplexing and power allocation schemes for all transceivers. Simulations results show appreciable gains when comparing the proposed solution to different schemes from the literature.

  12. Investigation of the physical parameters of duplex stainless steel (DSS surface integrity after turning

    Directory of Open Access Journals (Sweden)

    G. Krolczyk

    2015-01-01

    Full Text Available The article presents the influence of machining parameters on the microhardness of surface integrity (SI after turning by means of a coated sintered carbide wedge with a coating with ceramic intermediate layer. The investigation comprised the influence of cutting speed on the SI microhardness in dry machining. The material under investigation was duplex stainless steel with two-phase ferritic-austenitic structure. The results obtained allow for conclusions concerning the exploitation features of processed machine parts.

  13. Influence of cold worked layer on susceptibility to stress corrosion of duplex stainless steel

    International Nuclear Information System (INIS)

    Labanowski, J.; Ossowska, A.; Cwiek, J.

    2001-01-01

    Stress corrosion cracking resistance of cold worked layers on duplex stainless steel was investigated. The surface layers were performed through burnishing treatment. Corrosion tests were performed with the use of Slow Strain Rate Test technique in boiling 35% MgCl 2 solution. It has been shown that burnishing treatment increases corrosion resistance of steel. The factor that improves stress corrosion cracking resistance is crack incubation time. (author)

  14. Detection and quantification of beef and pork materials in meat products by duplex droplet digital PCR

    OpenAIRE

    Cai, Yicun; He, Yuping; Lv, Rong; Chen, Hongchao; Wang, Qiang; Pan, Liangwen

    2017-01-01

    Meat products often consist of meat from multiple animal species, and inaccurate food product adulteration and mislabeling can negatively affect consumers. Therefore, a cost-effective and reliable method for identification and quantification of animal species in meat products is required. In this study, we developed a duplex droplet digital PCR (dddPCR) detection and quantification system to simultaneously identify and quantify the source of meat in samples containing a mixture of beef (Bos t...

  15. Influence of the Martensitic Transformation on the Microscale Plastic Strain Heterogeneities in a Duplex Stainless Steel

    Science.gov (United States)

    Lechartier, Audrey; Martin, Guilhem; Comby, Solène; Roussel-Dherbey, Francine; Deschamps, Alexis; Mantel, Marc; Meyer, Nicolas; Verdier, Marc; Veron, Muriel

    2017-01-01

    The influence of the martensitic transformation on microscale plastic strain heterogeneity of a duplex stainless steel has been investigated. Microscale strain heterogeneities were measured by digital image correlation during an in situ tensile test within the SEM. The martensitic transformation was monitored in situ during tensile testing by high-energy synchrotron X-ray diffraction. A clear correlation is shown between the plasticity-induced transformation of austenite to martensite and the development of plastic strain heterogeneities at the phase level.

  16. The value of pre-discharge Duplex scanning in infrainguinal graft surveillance.

    Science.gov (United States)

    Wilson, Y G; Davies, A H; Currie, I C; McGrath, C; Morgan, M; Baird, R N; Lamont, P M

    1995-08-01

    Protocols and criteria for Duplex-based graft surveillance programmes (GS) vary widely as to the optimum regimens for maximising detection of "at risk" grafts. Few centres recommend starting GS before discharge. The aim of this study was to audit our experience with respect to early scanning. Vascular Studies Unit, Bristol Royal Infirmary. The records of 123 patients entering GS from January 1992 were reviewed. Patients were scanned at 1 week, 6 weeks and 3, 6, 9 and 12 months post-bypass. Haemodynamic criteria used were a peak mean velocity (PMV) less than 45 cm/s and a focal velocity disturbance with a V2/V1 ratio of 1.5 or more. Forty-six abnormalities (37% detection rate) were identified on scans within one week. In all cases, on-table completion studies with either arteriography and/or flow measurements had failed to identify the anomalies subsequently detected by Duplex. At 1 week, six grafts had occluded, 27 had a focal PMV increase (mean V2/V1 ratio: 2.6; range 1.5-4.3), four had low flow velocities, four had arteriovenous fistulae, one contained mobile thrombus, two had retained cusps and two had hamstring entrapment. Of 40 patent, but compromised grafts, 18 warranted immediate investigation. Of the 27 patients with velocity disturbances on Duplex, 25 were simply observed but, eight have since required intervention for definitive stenoses at these sites which, in retrospect, were evident within the first postoperative week. Pre-discharge scanning is a useful modality for detecting technical problems. Intrinsic graft abnormalities, possibly the sites of future definitive stenoses, have been visualised even at 1 week and once identified, can be more closely scrutinised thereafter. Pre-discharge colour Duplex is recommended as standard practice for quality control after infrainguinal bypass.

  17. Interference Management in Full-Duplex Cellular Networks with Partial Spectrum Overlap

    KAUST Repository

    Randrianantenaina, Itsikiantsoa; Dahrouj, Hayssam; Elsawy, Hesham; Alouini, Mohamed-Slim

    2017-01-01

    Full-duplex (FD) communication is promoted to double the spectral efficiency when compared to the halfduplex (HD) counterpart. In the context of cellular networks, however, FD communication exacerbates the aggregate uplink and downlink interference, which diminishes the foreseen FD gains. This paper considers a flexible duplex system, denoted by -duplex (-D) system, wherein a fine-grained bandwidth control for each uplink/downlink channel pair in each base station (BS) is allowed, which also leads to partial spectrum overlap between the uplink and downlink channels. The paper addresses the resulting interference management problem by maximizing a network-wide rate-based utility function subject to uplink/downlink power constraints, so as to determine userto- BS association, user-to-channel scheduling, the UL and DL transmit powers, and the fraction of spectrum overlap between UL and DL for every user, under the assumption that the number of available channels and users are equal. The paper solves such a non-convex mixed-integer optimization problem in an iterative way by decoupling the problem into several subproblems. Particularly, the user-to-BS association problem is solved using a matching algorithm that is a generalization of the stable marriage problem. The scheduling problem is solved by iterative Hungarian algorithm. The power and spectrum overlap problem is solved by successive convex approximation. The proposed iterative strategy guarantees an efficient one-toone user to BS and channel assignment. It further provides optimized flexible duplexing and power allocation schemes for all transceivers. Simulations results show appreciable gains when comparing the proposed solution to different schemes from the literature.

  18. The cardiac muscle duplex as a method to study myocardial heterogeneity

    Science.gov (United States)

    Solovyova, O.; Katsnelson, L.B.; Konovalov, P.V.; Kursanov, A.G.; Vikulova, N.A.; Kohl, P.; Markhasin, V.S.

    2014-01-01

    This paper reviews the development and application of paired muscle preparations, called duplex, for the investigation of mechanisms and consequences of intra-myocardial electro-mechanical heterogeneity. We illustrate the utility of the underlying combined experimental and computational approach for conceptual development and integration of basic science insight with clinically relevant settings, using previously published and new data. Directions for further study are identified. PMID:25106702

  19. Mechanical properties of duplex steel welded joints in large-size constructions

    OpenAIRE

    J. Nowacki

    2012-01-01

    Purpose: On the basis of sources and own experiments, the analysis of mechanical properties, applications as well as material and technological problems of ferritic-austenitic steel welding were carried out. It was shown the area of welding applications, particularly welding of large-size structures, on the basis of example of the FCAW method of welding of the UNS S3 1803 duplex steel in construction of chemical cargo ships.Design/methodology/approach: Welding tests were carried out for duple...

  20. Problems in repair-welding of duplex-treated tool steels

    OpenAIRE

    T. Muhič; J. Tušek; M. Pleterski; D. Bombač

    2009-01-01

    The present paper addresses problems in laser welding of die-cast tools used for aluminum pressure die-castings and plastic moulds. To extend life cycle of tools various surface improvements are used. These surface improvements significantly reduce weldability of the material. This paper presents development of defects in repair welding of duplex-treated tool steel. The procedure is aimed at reduction of defects by the newly developed repair laser welding techniques. Effects of different repa...

  1. Problemi kod reparaturnog zavarivanja alatnog čelika sa duplex zaštitom

    OpenAIRE

    Muhič, T.; Tušek, J.; Pleterski, M.; Bombač, D.

    2009-01-01

    The present paper addresses problems in laser welding of die-cast tools used for aluminum pressure die-castings and plastic moulds. To extend life cycle of tools various surface improvements are used. These surface improvements significantly reduce weldability of the material. This paper presents development of defects in repair welding of duplex-treated tool steel. The procedure is aimed at reduction of defects by the newly developed repair laser welding techniques. Effects of different repa...

  2. Electron transfer in DNA duplexes containing 2-methyl-1,4-naphthoquinone

    OpenAIRE

    Bergeron, François; Houde, Daniel; Hunting, Darel J.; Wagner, J. Richard

    2004-01-01

    2-Methyl-1,4-naphthoquinone (menadione, MQ) was linked to synthetic oligonucleotides and exposed to near-UV light to generate base radical cations in DNA. This model system of electron transfer induced alkali-labile breaks at GG doublets, similar to anthraquinone and metallointercalators systems. In sharp contrast to other systems, the photolysis of MQ–DNA duplexes gave interstrand cross-links and alkali-labile breaks at bases on the complementary strand opposite the MQ moiety. For sequences ...

  3. Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

    KAUST Repository

    Soury, Hamza

    2017-03-14

    This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have non-line of sight (NLOS) interfering link. Consequently, we study the interferer limited problem that appears between NLOS HD users-pair that are scheduled on the same FD channel. The distribution of the interference is first characterized via its distribution function, which is derived in closed form. Then, a comprehensive performance assessment for the proposed pairing scheme is provided by assuming Extended Generalized- $cal{K}$ (EGK) fading for the downlink and studying different modulation schemes. To this end, a unified closed form expression for the average symbol error rate is derived. Furthermore, we show the effective downlink throughput gain harvested by the pairing NLOS users as a function of the average signal-to-interferenceratio when compared to an idealized HD scenario with neither interference nor noise. Finally, we show the minimum required channel gain pairing threshold to harvest downlink throughput via the FD operation when compared to the HD case for each modulation scheme.

  4. Early evaluation of renal hemodynamic alterations in type I diabetes mellitus with duplex ultrasound

    Directory of Open Access Journals (Sweden)

    Saif Aasem

    2010-01-01

    Full Text Available To evaluate the role of renal duplex ultrasonography in the detection of early alte-ration of renal blood flow in type I diabetic patients, we studied with duplex ultrasound 32 patients with type I diabetes mellitus (19 males, 13 females, age range 8-19 years and 35 age and sex-matched controls. The resistivity indices (RIs and pulsatility indices (PIs of the main renal as well as intra-renal arteries were calculated. Compared with the healthy control subjects, diabetic patients had significantly higher resistivity indices (RIs in the intrarenal (segmental, arcuate and interlobar ar-teries (P= 0.001. The study, also revealed a significantly positive correlation between the RIs in the intrarenal arteries in diabetics and the albumin/creatinine ratio (r= 0.54, 0.52 and 0.51 respectively, glycated hemoglobin (r= 0.61, 0.59 and 0.63 respectively, as well as the estimated GFR (e-GFR (r= 0.53, 0.51 and 0.57 respectively. We conclude that the current study documented early intra-renal hemodynamic alterations in the form of pathologically elevated intrarenal RIs. This denotes the potential usefulness of duplex evaluation of the intrarenal arteries, as a noninvasive procedure, for monitoring type 1 diabetic patients to predict those at risk of diabetic nephropathy.

  5. Long-Range Vibrational Dynamics Are Directed by Watson-Crick Base Pairing in Duplex DNA.

    Science.gov (United States)

    Hithell, Gordon; Shaw, Daniel J; Donaldson, Paul M; Greetham, Gregory M; Towrie, Michael; Burley, Glenn A; Parker, Anthony W; Hunt, Neil T

    2016-05-05

    Ultrafast two-dimensional infrared (2D-IR) spectroscopy of a 15-mer A-T DNA duplex in solution has revealed structure-dependent vibrational coupling and energy transfer processes linking bases with the sugar-phosphate backbone. Duplex melting induces significant changes in the positions of off-diagonal peaks linking carbonyl and ring-stretching vibrational modes of the adenine and thymine bases with vibrations of the phosphate group and phosphodiester linkage. These indicate that Watson-Crick hydrogen bonding and helix formation lead to a unique vibrational coupling arrangement of base vibrational modes with those of the phosphate unit. On the basis of observations from time-resolved 2D-IR data, we conclude that rapid energy transfer processes occur between base and backbone, mediated by additional modes located on the deoxyribose moiety within the same nucleotide. These relaxation dynamics are insensitive to duplex melting, showing that efficient intramolecular energy relaxation to the solvent via the phosphate groups is the key to excess energy dissipation in both single- and double-stranded DNA.

  6. Gallblader varices in children with portal cavernoma: duplex-Doppler and color Doppler ultrasound studies

    International Nuclear Information System (INIS)

    Muro, D.; Sanguesa, C.; Lopez, A.

    1998-01-01

    To determine the prevalence of varices in the gallbladder wall, observed by duplex-Doppler and color Doppler ultrasound, in children with cavernoma of the portal vein. Nineteen patients with portal hypertension were studied prospectively by duplex-Doppler and color Doppler ultrasound: 12 of the patients had developed a cavernoma of the portal vein. The presence of peri vesicular varices was assessed in the group of patients with portal cavernoma. Duplex-Doppler and color Doppler ultrasound disclosed the presence of varices in gallbladder wall in nine of the 12 patients (75%). The varices appeared as anechoic and serpiginous areas, and Doppler ultrasound revealed slowed venous flow. However, the three patients in whom gallbldder varices were not detected presented collateral gastric ciculation and spontaneous splenorenal shunt. Gallbladder varices are common in children with portal vein cavernoma; they present hepatopetal flow. Their developments is not related to the size of the portal cavernoma, the presence of spontaneous portosystemic shunts, or endoscopic obliteration of gastric and esophageal varices. The detection of gallbladder varices in patients with portal hypertension who are to undergo biliary surgery is highly important for the surgeon, helping to avoid perioperative complications. (Author) 15 refs

  7. Uncomplicated duplex kidney and DMSA scintigraphy in children with urinary tract infection

    Energy Technology Data Exchange (ETDEWEB)

    Stokland, Eira [The Sahlgrenska Academy at Goeteborg University, Department of Paediatric Radiology, Goeteborg (Sweden); The Queen Silvia Children' s Hospital, Department of Paediatric Radiology, Goeteborg (Sweden); Jodal, Ulf; Swerkersson, Svante; Hansson, Sverker [The Sahlgrenska Academy at Goeteborg University, Department of Paediatrics, Goeteborg (Sweden); Sixt, Rune [The Sahlgrenska Academy at Goeteborg University, Department of Paediatric Clinical Physiology, Goeteborg (Sweden)

    2007-08-15

    Renal duplication is the most common malformation of the urinary tract and is frequently seen among children with urinary tract infection (UTI). To evaluate problems in the interpretation of dimercaptosuccinic acid (DMSA) scintigraphy and to establish the range of relative function in uncomplicated unilateral duplication. Retrospective analysis of 303 children less than 2 years of age with first time non-obstructive urinary tract infection investigated by both urography and DMSA scintigraphy. At DMSA scintigraphy, renal lesions and/or relative function below 45% was considered abnormal. Urography was used as reference for the diagnosis of duplication. Duplex kidneys were found in 22 of 303 patients (7%). Of the 16 children with unilateral duplication, 10 had bilaterally undamaged kidneys with a range of relative function varying between 51% and 57% in the duplex kidney. In two of the children with unilateral duplication the imaging results were discordant. There was risk of underdiagnosis as well as overdiagnosis of renal damage at scintigraphy. Although it is important to be aware of this risk, the rate of misinterpretation was low. A range of 51% to 57% can be used as the limit for normality of the relative function of a unilateral duplex kidney. (orig.)

  8. Hammerhead ribozyme activity and oligonucleotide duplex stability in mixed solutions of water and organic compounds

    Directory of Open Access Journals (Sweden)

    Shu-ichi Nakano

    2014-01-01

    Full Text Available Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme and the thermodynamic stability of an oligonucleotide duplex. The compounds with a net neutral charge, such as poly(ethylene glycol, small primary alcohols, amide compounds, and aprotic solvent molecules, added at high concentrations changed the ribozyme-catalyzed RNA cleavage rate, with the magnitude of the effect dependent on the NaCl concentration. These compounds also changed the thermodynamic stability of RNA base pairs of an oligonucleotide duplex and its dependence on the NaCl concentration. Specific interactions with RNA molecules and reduced water activity could account for the inhibiting effects on the ribozyme catalysis and destabilizing effects on the duplex stability. The salt concentration dependence data correlated with the dielectric constant, but not with water activity, viscosity, and the size of organic compounds. This observation suggests the significance of the dielectric constant effects on the RNA reactions under molecular crowding conditions created by organic compounds.

  9. Relationship between microstructure and fracture types in a UNS S32205 duplex stainless steel

    Directory of Open Access Journals (Sweden)

    Maria Victoria Biezma

    2013-01-01

    Full Text Available Duplex stainless steels are susceptible to the formation of sigma phase at high temperature which could potentially be responsible for catastrophic service failure of components. Thermal treatments were applied to duplex stainless steels in order to promote the precipitation of different fractions of sigma phase into a ferrite-austenite microstructure. Quantitative image analysis was employed to characterize the microstructure and Charpy impact tests were used in order to evaluate the mechanical degradation caused by sigma phase presence. The fracture morphology of the Charpy test specimens were thoroughly observed in SEM, looking for a correlation between the microstructure and the fracture types in UNS S32205 duplex stainless steel. The main conclusion is the strong embrittlement effect of sigma phase since it is possible to observe a transition from transgranular fracture to intergranular fracture as increases the percentage of sigma phase. Thus, the mixed modes of fracture are predominant in the present study with high dependence on sigma phase percentages obtained by different thermal treatments.

  10. Influence of sigma-phase formation on the localized corrosion behavior of a duplex stainless steel

    International Nuclear Information System (INIS)

    Adhe, K.N.; Kain, V.; Madangopal, K.; Gadiyar, H.S.

    1996-01-01

    Because of their austenitic-ferritic microstructures, duplex stainless steels offer a good combination of mechanical and corrosion resistance properties. However, heat treatments can lower the mechanical strength of these stainless steels as well as render them susceptible to intergranular corrosion (IGC) and pitting corrosion. In this study, a low-carbon (0.02%) duplex stainless steel is subjected to various heat treatments at 450 to 950 C for 30 min to 10 h. The heat-treated samples than undergo ASTM IGC and pitting corrosion tests, and the results are correlated with the microstructures obtained after each heat treatment. In the absence of Cr 23 C 6 precipitation, σ-phase precipitates render this duplex stainless steel susceptible to IGC and pitting corrosion. Even submicroscopic σ-phase precipitates are deleterious for IGC resistance. Longer-duration heat treatments (at 750 to 850 C) induce chromium diffusion to replenish the chromium-depleted regions around the σ-phase precipitates and improve IGC resistance; pitting resistance, however, is not fully restored. Various mechanisms of σ-phase formation are discussed to show that regions adjacent to σ-phase are depleted of chromium and molybdenum. The effect of chemical composition (pitting resistance equivalent) on the pitting resistance of various stainless steels is also noted

  11. Preliminary study of cost benefits associated with duplex fuel pellets of the LOWI type

    International Nuclear Information System (INIS)

    Ainscough, J.B.; Coucill, D.N.; Howl, D.A.; Jensen, A.; Misfeldt, I.

    1983-01-01

    Duplex UO 2 pellets, which consist of an outer enriched annulus and a depleted or natural core, can provide a solution to the problem of stress corrosion cracking failures, which have led to constraints being placed on ramp rates in power reactors. An analysis of the reactor physics and the performance of duplex pellets is presented in the context of a 17 X 17 pressurized water reactor fuel rod design. The study has been based on the particular type of duplex pellet in which the core and the annulus are physically separate; this is called ''LOWI'' after the Danish design. At low burnup, this fuel shows a significant improvement in power ramp performance compared with standard fuel. At higher burnup, the benefits are less certain but as the severity of the ramp will usually be less in high burnup fuel simply because of the reduced rating, the reduction in benefit may not be significant. If the gap between the core and annulus persists to high burnup, there will be no loss of benefit. Economic calculations and a cost-benefit analysis are presented to show the number of extra full-power hours of reactor operation that must be obtained in order to outweigh the additional fabrication costs associated with this fuel

  12. Efficient Cooperative Protocols for Full-Duplex Relaying over Nakagami-m Fading Channels

    KAUST Repository

    Khafagy, Mohammad Galal

    2015-02-24

    In this work, efficient protocols are studied for full-duplex relaying (FDR) with loopback interference over Nakagami-m block fading channels. Recently, a selective decodeand- forward (DF) protocol was proposed for FDR, and was shown to outperform existing protocols in terms of outage over Rayleigh-fading channels. In this work, we propose an incremental selective DF protocol that offers additional power savings, yet yields the same outage performance. We evaluate their outage performance over independent non-identically distributed Nakagami-m fading links, and study their relative performance in terms of the signal-to-noise ratio cumulative distribution function via closed-form expressions. The offered diversity gain is also derived. In addition, we study their performance relative to their half-duplex counterparts, as well as known non-selective FDR protocols. We corroborate our theoretical results with simulation, and confirm that selective cooperation protocols outperform the known non-selective protocols in terms of outage. Finally, we show that depending on the loopback interference level, the proposed protocols can outperform their half-duplex counterparts when high spectral efficiencies are targeted.

  13. Efficient Cooperative Protocols for Full-Duplex Relaying over Nakagami-m Fading Channels

    KAUST Repository

    Khafagy, Mohammad Galal; Tammam, Amr; Alouini, Mohamed-Slim; Aissa, Sonia

    2015-01-01

    In this work, efficient protocols are studied for full-duplex relaying (FDR) with loopback interference over Nakagami-m block fading channels. Recently, a selective decodeand- forward (DF) protocol was proposed for FDR, and was shown to outperform existing protocols in terms of outage over Rayleigh-fading channels. In this work, we propose an incremental selective DF protocol that offers additional power savings, yet yields the same outage performance. We evaluate their outage performance over independent non-identically distributed Nakagami-m fading links, and study their relative performance in terms of the signal-to-noise ratio cumulative distribution function via closed-form expressions. The offered diversity gain is also derived. In addition, we study their performance relative to their half-duplex counterparts, as well as known non-selective FDR protocols. We corroborate our theoretical results with simulation, and confirm that selective cooperation protocols outperform the known non-selective protocols in terms of outage. Finally, we show that depending on the loopback interference level, the proposed protocols can outperform their half-duplex counterparts when high spectral efficiencies are targeted.

  14. Ultrasonic Characterization And Micro-Structural Studies On 2205 Duplex Stainless Steel In Thermal Variations

    Directory of Open Access Journals (Sweden)

    Bernice Victoria

    2015-08-01

    Full Text Available Abstract Due to increasing concern on potential impact of materials on human health and environment the materials used in hygienic applications should be durable corrosion resistant clean surface etc. Type 2205 duplex stainless steel is a preferred material for use in biomedical pharmaceutical nuclear pressure vessels chemical tankers etc. it exhibits good mechanical strength and high resistance to corrosion. The strength toughness hardness of such materials are usually determined by destructive tests. However continuous destructive measurements are generally difficult to perform during the productive process which creates a need for a fast and easy nondestructive method of material characterization. Microstructural changes in duplex stainless steel due to changes in annealing temperature are characterized by ultrasonic pulse echo technique and optical microscopy. Type 2205 duplex stainless steel are heat treated at 1000 deg C 1050 deg C 1100 deg C 1150 deg C and 1200 deg C for 15 min and water quenched. There is an appreciable change in the morphology of all the heat treated samples and the ultrasonic velocity is dependent on both ferrite and austenite ratio and the grain size.

  15. Duplex ultrasonography in the hemorrhagic fever with renal syndrome; Correlation with laboratory findings

    International Nuclear Information System (INIS)

    Han, Chun Hee; Cho, K. S.; Auh, Y. h.; Park, C. S.; Park, S. K.; Kim, S. B.

    1994-01-01

    Assuming that the duplex Doppler sonography might be useful in predicting the disease evolution of hemorrhagic fever with renal syndrome, we compared the resistive index (RI) with the clinical and laboratory findings in 18 patients. We underwent 30 duplex Doppler examinations in 18 patients: one examination in nine, two examinations in six, and three examinations in three patients. Duplex Dopper waveforms were obtained from the main, segmental,interlobar, and arcuate arteries of both kidneys, and the RI was calculated for each study. In oliguric phase, the mean RI was high (average, 0.94), and the serum BUN(averate, 92.3mg/dl) and creatinine(average, 10.4mg/dl) levels were elevated. In diuretic phase the mean RI was normalized (average, 0.7), and the serum BUN(average, 31.1mg/dl)and serum creatinine (average, 2.9mg/dl) levels were low. There was statistically significant correlation between the mean RI and the serum levels of BUN and creatinine and 24 hour urine output (P<0.001). We conclude that the mean RI is a useful indicator in predicting the disease evolution in patients with hemorrhagic fever with renal syndrome

  16. Phase transitions in the q -voter model with noise on a duplex clique

    Science.gov (United States)

    Chmiel, Anna; Sznajd-Weron, Katarzyna

    2015-11-01

    We study a nonlinear q -voter model with stochastic noise, interpreted in the social context as independence, on a duplex network. To study the role of the multilevelness in this model we propose three methods of transferring the model from a mono- to a multiplex network. They take into account two criteria: one related to the status of independence (LOCAL vs GLOBAL) and one related to peer pressure (AND vs OR). In order to examine the influence of the presence of more than one level in the social network, we perform simulations on a particularly simple multiplex: a duplex clique, which consists of two fully overlapped complete graphs (cliques). Solving numerically the rate equation and simultaneously conducting Monte Carlo simulations, we provide evidence that even a simple rearrangement into a duplex topology may lead to significant changes in the observed behavior. However, qualitative changes in the phase transitions can be observed for only one of the considered rules: LOCAL&AND. For this rule the phase transition becomes discontinuous for q =5 , whereas for a monoplex such behavior is observed for q =6 . Interestingly, only this rule admits construction of realistic variants of the model, in line with recent social experiments.

  17. Deep vein thrombosis of lower extremity: What is the most important finding in duplex Doppler sonography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Soo; Koh, Byung Hee; Cho, On Koo; Rhim, Hyun Chul; Seo, Heung Suk; Hahm, Chang Kok; Kwak, Jin Young [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    1993-12-15

    The positive findings of deep vein thrombosis on duplex Doppler ultrasonography such as intraluminal clot,non-compressibility of the venous lumen and abnormal or absent Doppler shift signal are well known. However, relatively hypoechoic thrombus is not always seen in sonography, and the vein is frequently compressible in partial thrombosis. In order to evaluate the most common and important findings of deep vein thrombosis, we analysed the findings at duplex Doppler ultrasound in 19 patients and compared the results with those of contrast venography in 11 patients. Duplex Doppler ultrasound examination of the common femoral and popliteal veins was performed for one extremity in 14 patients, and for both extremities in 5 (total 24 extremities). Contrast venography was performed for one extremity in 7 patients, and for both sides in 4 (total 15 extremities).Thrombosis was seen in 45.8%, non-compressibility of lumen in 75%, absent or decreased Doppler signal from common femoral vein in 95.8%. Thrombosis was seen in 41.7%, non-compressibility of lumen in 70.8%, absent or decreased Doppler shift signal from popliteal vein in 95.8%. We conclude that abnormal or absent Doppler shift signal is the most sensitive and important finding of the deep vein thrombosis

  18. Resolution of carotid stenosis pre-carotid intervention: A case for selective preoperative duplex ultrasound.

    Science.gov (United States)

    Ali, Abid; Ashrafi, Mohammed; Zeynali, Iraj

    2015-01-01

    Spontaneous resolution of carotid stenosis is a phenomenon that has been described in literature in the past. At present it is not routine practise to scan patients prior to carotid endarterectomy surgery within the UK. A 58 year old female presented to hospital with a history of sudden onset headache and left sided weakness. CT head showed findings in keeping with an acute right MCA territory infarct. A duplex ultrasound scan showed echolucent material in the right internal carotid artery forming a greater than 95% stenosis. The scan was unable to visualise the patency of the vessel distally due to the position of the mandible. The patient was provisionally listed for carotid endarterectomy. An MRA was requested prior to surgery to assess the patency of the distal internal carotid artery. The MRA of the carotids showed normal appearance of the common carotid, internal and vertebral arteries with no definite stenosis. A repeat duplex ultrasound confirmed there was no significant stenosis. The finding of complete resolution of stenosis on MRA was an unexpected event. Had the initial duplex imaging allowed visualisation of the distal vessel patency, our patient would have undergone unnecessary carotid surgery with the associated morbidity and mortality. This case report draws attention to the benefits of selective preoperative scanning, in sparing patients from unnecessary surgery as a result of finding occlusion or resolution of a previously diagnosed carotid stenosis. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Counterpart synchronization of duplex networks with delayed nodes and noise perturbation

    International Nuclear Information System (INIS)

    Wei, Xiang; Wu, Xiaoqun; Lu, Jun-an; Zhao, Junchan

    2015-01-01

    In the real world, many complex systems are represented not by single networks but rather by sets of interdependent ones. In these specific networks, nodes in one network mutually interact with nodes in other networks. This paper focuses on a simple representative case of two-layer networks (the so-called duplex networks) with unidirectional inter-layer couplings. That is, each node in one network depends on a counterpart in the other network. Accordingly, the former network is called the response layer and the latter network is the drive layer. Specifically, synchronization between each node in the drive layer and its counterpart in the response layer (counterpart synchronization (CS)) in these kinds of duplex networks with delayed nodes and noise perturbation is investigated. Based on the LaSalle-type invariance principle, a control technique is proposed and a sufficient condition is developed for realizing CS of duplex networks. Furthermore, two corollaries are derived as special cases. In addition, node dynamics within each layer can be varied and topologies of the two layers are not necessarily identical. Therefore, the proposed synchronization method can be applied to a wide range of multiplex networks. Numerical examples are provided to illustrate the feasibility and effectiveness of the results. (paper)

  20. Uncomplicated duplex kidney and DMSA scintigraphy in children with urinary tract infection

    International Nuclear Information System (INIS)

    Stokland, Eira; Jodal, Ulf; Swerkersson, Svante; Hansson, Sverker; Sixt, Rune

    2007-01-01

    Renal duplication is the most common malformation of the urinary tract and is frequently seen among children with urinary tract infection (UTI). To evaluate problems in the interpretation of dimercaptosuccinic acid (DMSA) scintigraphy and to establish the range of relative function in uncomplicated unilateral duplication. Retrospective analysis of 303 children less than 2 years of age with first time non-obstructive urinary tract infection investigated by both urography and DMSA scintigraphy. At DMSA scintigraphy, renal lesions and/or relative function below 45% was considered abnormal. Urography was used as reference for the diagnosis of duplication. Duplex kidneys were found in 22 of 303 patients (7%). Of the 16 children with unilateral duplication, 10 had bilaterally undamaged kidneys with a range of relative function varying between 51% and 57% in the duplex kidney. In two of the children with unilateral duplication the imaging results were discordant. There was risk of underdiagnosis as well as overdiagnosis of renal damage at scintigraphy. Although it is important to be aware of this risk, the rate of misinterpretation was low. A range of 51% to 57% can be used as the limit for normality of the relative function of a unilateral duplex kidney. (orig.)

  1. A full-duplex CATV/wireless-over-fiber lightwave transmission system.

    Science.gov (United States)

    Li, Chung-Yi; Lu, Hai-Han; Ying, Cheng-Ling; Cheng, Chun-Jen; Lin, Che-Yu; Wan, Zhi-Wei; Chen, Jian-Hua

    2015-04-06

    A full-duplex CATV/wireless-over-fiber lightwave transmission system consisting of one broadband light source (BLS), two optical interleavers (ILs), one intensity modulator, and one phase modulator is proposed and experimentally demonstrated. The downstream light is optically promoted from 10Gbps/25GHz microwave (MW) data signal to 10Gbps/100GHz and 10Gbps/50GHz millimeter-wave (MMW) data signals in fiber-wireless convergence, and intensity-modulated with 50-550 MHz CATV signal. For up-link transmission, the downstream light is phase-remodulated with 10Gbps/25GHz MW data signal in fiber-wireless convergence. Over a 40-km single-mode fiber (SMF) and a 10-m radio frequency (RF) wireless transport, bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed to perform well in such full-duplex CATV/wireless-over-fiber lightwave transmission systems. This full-duplex 100-GHz/50-GHz/25-GHz/550-MHz lightwave transmission system is an attractive alternative. This transmission system not only presents its advancement in the integration of fiber backbone and CATV/wireless feeder networks, but also it provides the advantages of a communication channel for higher data rates and bandwidth.

  2. Pulsed IR Heating Studies of Single-Molecule DNA Duplex Dissociation Kinetics and Thermodynamics

    Science.gov (United States)

    Holmstrom, Erik D.; Dupuis, Nicholas F.; Nesbitt, David J.

    2014-01-01

    Single-molecule fluorescence spectroscopy is a powerful technique that makes it possible to observe the conformational dynamics associated with biomolecular processes. The addition of precise temperature control to these experiments can yield valuable thermodynamic information about equilibrium and kinetic rate constants. To accomplish this, we have developed a microscopy technique based on infrared laser overtone/combination band absorption to heat small (≈10−11 liter) volumes of water. Detailed experimental characterization of this technique reveals three major advantages over conventional stage heating methods: 1), a larger range of steady-state temperatures (20–100°C); 2), substantially superior spatial (≤20 μm) control; and 3), substantially superior temporal (≈1 ms) control. The flexibility and breadth of this spatial and temporally resolved laser-heating approach is demonstrated in single-molecule fluorescence assays designed to probe the dissociation of a 21 bp DNA duplex. These studies are used to support a kinetic model based on nucleic acid end fraying that describes dissociation for both short (10 bp) DNA duplexes. These measurements have been extended to explore temperature-dependent kinetics for the 21 bp construct, which permit determination of single-molecule activation enthalpies and entropies for DNA duplex dissociation. PMID:24411254

  3. Microstructure and properties of duplex (Ti:N)-DLC/MAO coating on magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wei; Ke, Peiling [Ningbo Key Laboratory of Marine Protection Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Fang, Yong [Sir Run Run Shaw Hospital, School of Medicine, Zhe Jiang University, Zhejiang 310016 (China); Zheng, He [Ningbo Key Laboratory of Marine Protection Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Ningbo Key Laboratory of Marine Protection Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2013-04-01

    Ti and N co-doped diamond-like carbon ((Ti:N)-DLC) film was deposited on the MAO coated substrate using a hybrid beam deposition system, which consists of a DC magnetron sputtering of Ti target and a linear ion source (LIS) with C{sub 2}H{sub 2} and N{sub 2} precursor gas. The microstructure and properties of the duplex (Ti:N)-DLC/MAO coating were investigated. Results indicate that the (Ti:N)-DLC top film with TiN crystalline phase was formed. Ti and N co-doping resulted in the increasing I{sub D}/I{sub G} ratio. The significant improvement in the wear and corrosion resistance of duplex (Ti:N)-DLC/MAO coating was mainly attributed to the increased binding strength, lubrication characteristics and chemical inertness of (Ti:N)-DLC top film. The superior low-friction and anti-corrosion properties of duplex (Ti:N)-DLC/MAO coating make it a good candidate as protective coating on magnesium alloy.

  4. Adenine radicals generated in alternating AT duplexes by direct absorption of low-energy UV radiation.

    Science.gov (United States)

    Banyasz, Akos; Ketola, Tiia; Martínez-Fernández, Lara; Improta, Roberto; Markovitsi, Dimitra

    2018-04-17

    There is increasing evidence that the direct absorption of photons with energies that are lower than the ionization potential of nucleobases may result in oxidative damage to DNA. The present work, which combines nanosecond transient absorption spectroscopy and quantum mechanical calculations, studies this process in alternating adenine-thymine duplexes (AT)n. We show that the one-photon ionization quantum yield of (AT)10 at 266 nm (4.66 eV) is (1.5 ± 0.3) × 10-3. According to our PCM/TD-DFT calculations carried out on model duplexes composed of two base pairs, (AT)1 and (TA)1, simultaneous base pairing and stacking does not induce important changes in the absorption spectra of the adenine radical cation and deprotonated radical. The adenine radicals, thus identified in the time-resolved spectra, disappear with a lifetime of 2.5 ms, giving rise to a reaction product that absorbs at 350 nm. In parallel, the fingerprint of reaction intermediates other than radicals, formed directly from singlet excited states and assigned to AT/TA dimers, is detected at shorter wavelengths. PCM/TD-DFT calculations are carried out to map the pathways leading to such species and to characterize their absorption spectra; we find that, in addition to the path leading to the well-known TA* photoproduct, an AT photo-dimerization path may be operative in duplexes.

  5. Assessment of Duplex PCR for the simultaneous diagnose of Mycobacterium spp. and Brucella spp. in cattle

    Directory of Open Access Journals (Sweden)

    Ariel Escobar

    2013-03-01

    Full Text Available Tuberculosis and brucellosis remain important causes of morbidity and mortality in many countries, for the detection of both diseases requires efficient and sensitive tool for effectuate the diagnosis. This study was aimed to evaluate and compare the duplex PCR versus the nested PCR, for detection of Brucella spp. (BR and Mycobacterium spp. (TB. A total of 100 samples of tissues from tracheo-bronchial lymph nodes, bovine lung and bacterial isolate as positive controls were used. Were evaluated ten combinations of primers which were designed to flank the segment of the 16S rRNA sequence (RB and antigen gen MPB70 (TB, the best result for the Duplex PCR was obtained with the primers Bru-2F/Bru-2R for BR and Tub-1F/Tub-N-R for TB. The amplification of the products was 225 and 230-bp respectively. In order to compare the results of the proposed technique, all samples were initially analyzed and compared between PCR and nested PCR (Kappa, k = 0.85 and the concordance between Duplex PCR and nested PCR (k = 0.88 for the two bacteria was very good.

  6. Nitride alloy layer formation of duplex stainless steel using nitriding process

    Science.gov (United States)

    Maleque, M. A.; Lailatul, P. H.; Fathaen, A. A.; Norinsan, K.; Haider, J.

    2018-01-01

    Duplex stainless steel (DSS) shows a good corrosion resistance as well as the mechanical properties. However, DSS performance decrease as it works under aggressive environment and at high temperature. At the mentioned environment, the DSS become susceptible to wear failure. Surface modification is the favourable technique to widen the application of duplex stainless steel and improve the wear resistance and its hardness properties. Therefore, the main aim of this work is to nitride alloy layer on the surface of duplex stainless steel by the nitriding process temperature of 400°C and 450°C at different time and ammonia composition using a horizontal tube furnace. The scanning electron microscopy and x-ray diffraction analyzer are used to analyse the morphology, composition and the nitrided alloy layer for treated DSS. The micro hardnesss Vickers tester was used to measure hardness on cross-sectional area of nitrided DSS. After nitriding, it was observed that the hardness performance increased until 1100 Hv0.5kgf compared to substrate material of 250 Hv0.5kgf. The thickness layer of nitride alloy also increased from 5μm until 100μm due to diffusion of nitrogen on the surface of DSS. The x-ray diffraction results showed that the nitride layer consists of iron nitride, expanded austenite and chromium nitride. It can be concluded that nitride alloy layer can be produced via nitriding process using tube furnace with significant improvement of microstructural and hardness properties.

  7. Performance evaluation of duplex constructed wetlands for the treatment of diesel contaminated wastewater.

    Science.gov (United States)

    Mustapha, Hassana Ibrahim; Gupta, Pankaj Kumar; Yadav, Brijesh Kumar; van Bruggen, J J A; Lens, P N L

    2018-08-01

    A duplex constructed wetland (duplex-CW) is a hybrid system that combines a vertical flow (VF) CW as a first stage with a horizontal flow filter (HFF) as a second stage for a more efficient wastewater treatment as compared to traditional constructed wetlands. This study evaluated the potential of the hybrid CW system to treat influent wastewater containing diesel range organic compounds varying from C 7 - C 40 using a series of 12-week practical and numerical experiments under controlled conditions in a greenhouse (pH was kept at 7.0 ± 0.2, temperature between 20 and 23° C and light intensity between 85 and 100-μmol photons m -2 sec -1 for 16 h d -1 ). The VF CWs were planted with Phragmites australis and were spiked with different concentrations of NH 4 + -N (10, 30 and 60 mg/L) and PO 4 3- -P (3, 6 and 12 mg/L) to analyse their effects on the degradation of the supplied petroleum hydrocarbons. The removal rate of the diesel range organics considering the different NH 4 + -N and PO 4 3- -P concentrations were simulated using Monod degradation kinetics. The simulated results compared well with the observed database. The results showed that the model can effectively be used to predict biochemical transformation and degradation of diesel range organic compounds along with nutrient amendment in duplex constructed wetlands. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. G-quadruplexes Significantly Stimulate Pif1 Helicase-catalyzed Duplex DNA Unwinding*

    Science.gov (United States)

    Duan, Xiao-Lei; Liu, Na-Nv; Yang, Yan-Tao; Li, Hai-Hong; Li, Ming; Dou, Shuo-Xing; Xi, Xu-Guang

    2015-01-01

    The evolutionarily conserved G-quadruplexes (G4s) are faithfully inherited and serve a variety of cellular functions such as telomere maintenance, gene regulation, DNA replication initiation, and epigenetic regulation. Different from the Watson-Crick base-pairing found in duplex DNA, G4s are formed via Hoogsteen base pairing and are very stable and compact DNA structures. Failure of untangling them in the cell impedes DNA-based transactions and leads to genome instability. Cells have evolved highly specific helicases to resolve G4 structures. We used a recombinant nuclear form of Saccharomyces cerevisiae Pif1 to characterize Pif1-mediated DNA unwinding with a substrate mimicking an ongoing lagging strand synthesis stalled by G4s, which resembles a replication origin and a G4-structured flap in Okazaki fragment maturation. We find that the presence of G4 may greatly stimulate the Pif1 helicase to unwind duplex DNA. Further studies reveal that this stimulation results from G4-enhanced Pif1 dimerization, which is required for duplex DNA unwinding. This finding provides new insights into the properties and functions of G4s. We discuss the observed activation phenomenon in relation to the possible regulatory role of G4s in the rapid rescue of the stalled lagging strand synthesis by helping the replicator recognize and activate the replication origin as well as by quickly removing the G4-structured flap during Okazaki fragment maturation. PMID:25627683

  9. Environmental Degradation of Dissimilar Austenitic 316L and Duplex 2205 Stainless Steels Welded Joints

    Directory of Open Access Journals (Sweden)

    Topolska S.

    2017-12-01

    Full Text Available The paper describes structure and properties of dissimilar stainless steels welded joints between duplex 2205 and austenitic 316L steels. Investigations were focused on environmentally assisted cracking of welded joints. The susceptibility to stress corrosion cracking (SCC and hydrogen embrittlement was determined in slow strain rate tests (SSRT with the strain rate of 2.2 × 10−6 s−1. Chloride-inducted SCC was determined in the 35% boiling water solution of MgCl2 environment at 125°C. Hydrogen assisted SCC tests were performed in synthetic sea water under cathodic polarization condition. It was shown that place of the lowest resistance to chloride stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon was connected with undesirable structure of HAZ comprising of large fractions of ferrite grains with acicular austenite phase. Hydrogen assisted SCC tests showed significant reduction in ductility of duplex 2205 steel while austenitic 316L steel remains almost immune to degradation processes. SSR tests of dissimilar welded joints revealed a fracture in the area of austenitic steel.

  10. The effect of fiber laser parameters on microhardness and microstructure of duplex stainless steel

    Directory of Open Access Journals (Sweden)

    Mohammed Ghusoon R.

    2017-01-01

    Full Text Available An investigation was implement to study the influence of laser power, and speed of the welding on hardness, microstructure, and penetration of laser welding bead on plate duplex stainless steel, which is not exhibited so far. A fiber laser was selected for welding duplex stainless steel sheet with 2 mm thickness. Then, optical microscope (OM was used in the morphologic observation of cross section, penetration depth, and bead width. Microhardness of the welded sheet was measured using Vickers hardness. Profiles of hardness and microstructure were utilized to discriminate welding line and to propose superior welding parameters. The experimental results displayed that, a good quality of duplex steel welds can be acquired when a suitable fiber laser welding parameters were selected. It was found that microhardness profiles showed a rise in the hardness of the weld and heat-affected zones as the solidification process proceeds rapidly. Additionally, the crystal solidification process induced by the fiber laser welding was schematically clarified and systematically exposed.

  11. miRNA-like duplexes as RNAi triggers with improved specificity

    Directory of Open Access Journals (Sweden)

    Juan G. Betancur

    2012-07-01

    Full Text Available siRNA duplexes, the most common triggers of RNA interference, are first loaded into an Argonaute (Ago protein and then undergo unwinding via passenger strand cleavage, which requires the slicer activity of the Ago protein. In mammals, only Ago2 out of the four Ago proteins possesses such slicer activity. In contrast, miRNA/miRNA* duplexes often contain central mismatches that prevent slicer-dependent unwinding. Instead, mismatches in specific regions (seed and 3´-mid regions promote efficient slicer-independent unwinding by any of the four mammalian Ago proteins. Both slicer-dependent and slicer-independent unwinding mechanisms produce guide-containing RNA-induced silencing complex (RISC, which silences target mRNAs by cleavage, translational repression, and/or deadenylation that leads to mRNA decay. In this review, we summarize our current knowledge of the RISC assembly pathways, and describe a simple method to rationally design artificial miRNA/miRNA*-like duplexes and highlight its benefits to reduce the unwanted off-target effects without compromising the specific target silencing activity.

  12. Structural studies of the 5'-phenazinium-tethered matched and G-A-mismatched DNA duplexes by NMR spectroscopy.

    Science.gov (United States)

    Maltseva, T; Sandström, A; Ivanova, I M; Sergeyev, D S; Zarytova, V F; Chattopadhyaya, J

    1993-05-01

    The mechanism through which modified oligo-DNA analogues act as antisense repressors at the transcriptional and translational level of gene expression is based on the information content in the nucleotide sequence which is determined by the specific base pairing. The efficiency of such action is largely determined by the stability of the duplex formed between the oligonucleotide reagent and the target sequence and also by the mismatched base pairing, such as G-A, that occurs during replication or recombination. We herein report that the phenazinium (Pzn)-tethered matched duplex p(d(TGTTTGGC)):(Pzn)-p(d(CCAAACA)) (III) (Tm = 50 degrees C) has a much larger stability than the parent matched duplex p(d(TGTTTGGC)):p(d(CCAAACA)) (I) (Tm = 30 degrees C). On the other hand, the Pzn-tethered G-A-mismatched duplex p(d(TGTTTGGC)):(Pzn)-p(d(ACAAACA)) (IV) (Tm = 34 degrees C) is only slightly more stable than its parent mismatched duplex p(d(TGTTTGGC)):p(d(ACAAACA)) (Tm = 25 degrees C). A detailed 500 MHz NMR study and constrained MD refinements of NMR-derived structures have been undertaken for the DNA duplexes (I), (II), (III) and (IV) in order to understand the structural basis of stabilization of Pzn-tethered matched DNA duplex (delta Tm = 20 degrees C) compared to mismatched duplex (delta Tm = 9 degrees C). Assignment of the 1H-NMR (500 MHz) spectra of the duplexes has been carried out by 2D NOESY, HOHAHA and DQF-COSY experiments. The torsion angles have been extracted from the J-coupling constants obtained by simulation of most of the DQF-COSY cross-peaks using program SMART. The solution structure of the duplexes were assessed by an iterative hybride relaxation matrix method (MORASS) combined with NOESY distances and torsion angles restrained molecular dynamics (MD) using program Amber 4.0. The standard Amber 4.0 force-field parameters were used for the oligonucleotide in conjunction with the new parameters for Pzn residue which was obtained by full geometry

  13. Development of duplex real-time PCR for the detection of WSSV and PstDV1 in cultivated shrimp.

    Science.gov (United States)

    Leal, Carlos A G; Carvalho, Alex F; Leite, Rômulo C; Figueiredo, Henrique C P

    2014-07-05

    The White spot syndrome virus (WSSV) and Penaeus stylirostris penstyldensovirus 1 (previously named Infectious hypodermal and hematopoietic necrosis virus-IHHNV) are two of the most important viral pathogens of penaeid shrimp. Different methods have been applied for diagnosis of these viruses, including Real-time PCR (qPCR) assays. A duplex qPCR method allows the simultaneous detection of two viruses in the same sample, which is more cost-effective than assaying for each virus separately. Currently, an assay for the simultaneous detection of the WSSV and the PstDV1 in shrimp is unavailable. The aim of this study was to develop and standardize a duplex qPCR assay for the simultaneous detection of the WSSV and the PstDV1 in clinical samples of diseased L. vannamei. In addition, to evaluate the performance of two qPCR master mixes with regard to the clinical sensitivity of the qPCR assay, as well as, different methods for qPCR results evaluation. The duplex qPCR assay for detecting WSSV and PstDV1 in clinical samples was successfully standardized. No difference in the amplification of the standard curves was observed between the duplex and singleplex assays. Specificities and sensitivities similar to those of the singleplex assays were obtained using the optimized duplex qPCR. The analytical sensitivities of duplex qPCR were two copies of WSSV control plasmid and 20 copies of PstDV1 control plasmid. The standardized duplex qPCR confirmed the presence of viral DNA in 28 from 43 samples tested. There was no difference for WSSV detection using the two kits and the distinct methods for qPCR results evaluation. High clinical sensitivity for PstDV1 was obtained with TaqMan Universal Master Mix associated with relative threshold evaluation. Three cases of simultaneous infection by the WSSV and the PstDV1 were identified with duplex qPCR. The standardized duplex qPCR was shown to be a robust, highly sensitive, and feasible diagnostic tool for the simultaneous detection of the

  14. The Role of Duplex Scanning in the Selection of Patients with Critical Lower-Limb Ischemia for Infrainguinal Percutaneous Transluminal Angioplasty

    International Nuclear Information System (INIS)

    Loefberg, Anne-Marie; Karacagil, Sadettin; Hellberg, Anders; Bostroem, Annika; Ljungman, Christer; Ostholm, Goerel

    2001-01-01

    Purpose: To investigate the role of duplex scanning in the selection of patients with critical lower-limb ischemia (CLI) for infrainguinal percutaneous transluminal angioplasty (PTA).Methods: One hundred and sixty-two limbs with CLI (150 patients) that underwent duplex scanning within 3 months prior to conventional diagnostic angiography (n = 88) or infrainguinal PTA (n = 74) were retrospectively studied. The findings obtained from duplex scanning and angiography were analyzed in a masked fashion by two different investigators.Results: The accuracy, sensitivity, specificity, and negative and positive predictive values of duplex scanning in the selection of patients for infrainguinal PTA were 86%, 84%, 89%, 86%, and 87% respectively. Forty-two procedures (57%) were performed at multiple arterial segments. The accuracy of duplex scanning in the selection of femoropopliteal and crural lesions for PTA was over 85%. However, the sensitivity of duplex scanning in the selection of popliteal and crural lesions for PTA was 49% and 38% respectively, compared with 80% for superior femoral artery lesions. In 39% of patients who were correctly selected for PTA, duplex scanning misdiagnosed one of the multiple lesions treated by PTA.Conclusion: Duplex scanning can safely be used for the selection of patients for infrainguinal PTA. The sensitivity of duplex scanning in the selection of lesions for PTA was less satisfactory in the popliteal and crural arteries compared with the femoropopliteal arteries

  15. The Contribution of the Activation Entropy to the Gas-Phase Stability of Modified Nucleic Acid Duplexes

    Science.gov (United States)

    Hari, Yvonne; Dugovič, Branislav; Istrate, Alena; Fignolé, Annabel; Leumann, Christian J.; Schürch, Stefan

    2016-07-01

    Tricyclo-DNA (tcDNA) is a sugar-modified analogue of DNA currently tested for the treatment of Duchenne muscular dystrophy in an antisense approach. Tandem mass spectrometry plays a key role in modern medical diagnostics and has become a widespread technique for the structure elucidation and quantification of antisense oligonucleotides. Herein, mechanistic aspects of the fragmentation of tcDNA are discussed, which lay the basis for reliable sequencing and quantification of the antisense oligonucleotide. Excellent selectivity of tcDNA for complementary RNA is demonstrated in direct competition experiments. Moreover, the kinetic stability and fragmentation pattern of matched and mismatched tcDNA heteroduplexes were investigated and compared with non-modified DNA and RNA duplexes. Although the separation of the constituting strands is the entropy-favored fragmentation pathway of all nucleic acid duplexes, it was found to be only a minor pathway of tcDNA duplexes. The modified hybrid duplexes preferentially undergo neutral base loss and backbone cleavage. This difference is due to the low activation entropy for the strand dissociation of modified duplexes that arises from the conformational constraint of the tc-sugar-moiety. The low activation entropy results in a relatively high free activation enthalpy for the dissociation comparable to the free activation enthalpy of the alternative reaction pathway, the release of a nucleobase. The gas-phase behavior of tcDNA duplexes illustrates the impact of the activation entropy on the fragmentation kinetics and suggests that tandem mass spectrometric experiments are not suited to determine the relative stability of different types of nucleic acid duplexes.

  16. Structural Insights into the Quadruplex-Duplex 3' Interface Formed from a Telomeric Repeat: A Potential Molecular Target.

    Science.gov (United States)

    Russo Krauss, Irene; Ramaswamy, Sneha; Neidle, Stephen; Haider, Shozeb; Parkinson, Gary N

    2016-02-03

    We report here on an X-ray crystallographic and molecular modeling investigation into the complex 3' interface formed between putative parallel stranded G-quadruplexes and a duplex DNA sequence constructed from the human telomeric repeat sequence TTAGGG. Our crystallographic approach provides a detailed snapshot of a telomeric 3' quadruplex-duplex junction: a junction that appears to have the potential to form a unique molecular target for small molecule binding and interference with telomere-related functions. This unique target is particularly relevant as current high-affinity compounds that bind putative G-quadruplex forming sequences only rarely have a high degree of selectivity for a particular quadruplex. Here DNA junctions were assembled using different putative quadruplex-forming scaffolds linked at the 3' end to a telomeric duplex sequence and annealed to a complementary strand. We successfully generated a series of G-quadruplex-duplex containing crystals, both alone and in the presence of ligands. The structures demonstrate the formation of a parallel folded G-quadruplex and a B-form duplex DNA stacked coaxially. Most strikingly, structural data reveals the consistent formation of a TAT triad platform between the two motifs. This triad allows for a continuous stack of bases to link the quadruplex motif with the duplex region. For these crystal structures formed in the absence of ligands, the TAT triad interface occludes ligand binding at the 3' quadruplex-duplex interface, in agreement with in silico docking predictions. However, with the rearrangement of a single nucleotide, a stable pocket can be produced, thus providing an opportunity for the binding of selective molecules at the interface.

  17. Standard duplex criteria overestimate the degree of stenosis after eversion carotid endarterectomy.

    Science.gov (United States)

    Benzing, Travis; Wilhoit, Cameron; Wright, Sharee; McCann, P Aaron; Lessner, Susan; Brothers, Thomas E

    2015-06-01

    The eversion technique for carotid endarterectomy (eCEA) offers an alternative to longitudinal arteriotomy and patch closure (pCEA) for open carotid revascularization. In some reports, eCEA has been associated with a higher rate of >50% restenosis of the internal carotid when it is defined as peak systolic velocity (PSV) >125 cm/s by duplex imaging. Because the conformation of the carotid bifurcation may differ after eCEA compared with native carotid arteries, it was hypothesized that standard duplex criteria might not accurately reflect the presence of restenosis after eCEA. In a case-control study, the outcomes of all patients undergoing carotid endarterectomy by one surgeon during the last 10 years were analyzed retrospectively, with a primary end point of PSV >125 cm/s. Duplex flow velocities were compared with luminal diameter measurements for any carotid computed tomography arteriography or magnetic resonance angiography study obtained within 2 months of duplex imaging, with the degree of stenosis calculated by the methodology used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST) as well as cross-sectional area (CSA) reduction. Simulations were generated and analyzed by computational model simulations of the eCEA and pCEA arteries. Eversion and longitudinal arteriotomy with patch techniques were used in 118 and 177 carotid arteries, respectively. Duplex follow-up was available in 90 eCEA arteries at a median of 16 (range, 2-136) months and in 150 pCEA arteries at a median of 41 (range, 3-115) months postoperatively. PSV >125 cm/s was present at some time during follow-up in 31% of eCEA and pCEA carotid arteries, each, and in the most recent duplex examination in 7% after eCEA and 21% after pCEA (P = .003), with no eCEA and two pCEA arteries occluding completely during follow-up (P = .29). In 19 carotid arteries with PSV >125 cm/s after angle correction (median, 160 cm/s; interquartile range

  18. Investigation of corrosion and wear mechanisms in hard material-reinforced duplex steel coatings; Untersuchungen zum Korrosions- und Verschleissverhalten von hartstoffverstaerkten `Duplex`-Schutzschichten. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bouaifi, B. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Schweisstechnik und Trennende Fertigungsverfahren; Goellner, J. [Technische Univ. Magdeburg (Germany). Inst. fuer Werkstofftechnik und Werkstoffpruefung

    1998-09-30

    The hard-material reinforced duplex steel coatings were deposited by plasma arc two-powder surfacing. By varying the angle of the hard materials feeding process, the deposition of the carbides was optimized so that they are deposited into the matrix in the trailing zone of the welding torch under conditions of very low thermal effects near the freezing point of the weld pool. Microstructural studies revealed that the deposition of the hard materials prevents devlopment of the typical, ferritic-austenitic microstructure of duplex steels. Due to a dissolution and diffusion process, the microstructure of the matrix takes up carbon and chromium or tungsten, depending on the carbide, thus enhancing the austenitic material in the microstructure. The wear behaviour of the surface deposits was found to be very good, wear being reduced by a factor of 6, irrespective of the type of carbide. The friction-affected surfaces showed no dissolving effects or cracking. The corrosion behaviour in sulfuric acid is also good. The welded deposits exhibited the typical behaviour of a passive material. Wear mechanisms slightly reduce the resistance. The behaviour of various specimens in artificial seawater could be distinctly assessed. Small grain fractions and pre-heating temperatures of 100 C have a beneficial effect on the corrosion resistance. The technique recommends itself for applications such as coatings for baffle plates used in flue gas desulfurisation, pipes, pump components, flanges or nozzles, or for recurrent coating of system components affected by abrasive corrosion. (orig./CB) [Deutsch] Zur Herstellung hartstoffverstaerkter Duplex-Beschichtungen wurde das Plasma-Zwei-Pulver-Auftragschweissverfahren verwendet. Hierbei wurde durch Variation des Zufuhrwinkels der Hartstoffe der Einbringungsort der Karbide optimiert, so dass diese im Nachlauf des Schweissbrenners mit sehr geringer thermischer Beeinflussung im erstarrungsnahen Schmelzbadbereich in die Matrix eingelagert

  19. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study

    International Nuclear Information System (INIS)

    Cantador, Alex Aparecido; Siqueira, Daniel Emilio Dalledone; Jacobsen, Octavio Barcellos; Baracat, Jamal; Pereira, Ines Minniti Rodrigues; Menezes, Fabio Hüsemann; Guillaumon, Ana Terezinha

    2016-01-01

    Objective: To compare duplex ultrasound and computed tomography (CT) angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods: This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results: The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01). Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion: Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation. (author)

  20. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Cantador, Alex Aparecido; Siqueira, Daniel Emilio Dalledone; Jacobsen, Octavio Barcellos; Baracat, Jamal; Pereira, Ines Minniti Rodrigues; Menezes, Fabio Hüsemann; Guillaumon, Ana Terezinha, E-mail: alex_cantador@yahoo.com.br [Universidade Estadual de Campinas (FCM/UNICAMP), Campinas, SP (Brazil). Faculdade de Ciencias Medicas

    2016-07-15

    Objective: To compare duplex ultrasound and computed tomography (CT) angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods: This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results: The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01). Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion: Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation. (author)

  1. Effects of fabrication conditions on mechanical properties and microstructure of duplex β″-Al2O3 solid electrolyte

    International Nuclear Information System (INIS)

    Canfield, Nathan L.; Kim, Jin Y.; Bonnett, Jeff F.; Pearson, R.L.; Sprenkle, Vincent L.; Jung, Keeyoung

    2015-01-01

    Highlights: • The concept of duplex BASEs is presented as a method to lower the ASR for NBBs. • Duplex BASEs consist of thin dense electrolyte and porous support. • Strength of converted BASEs shows a different trend from as-sintered samples. • Cell orientation gives significant impact on strength of duplex BASEs. - Abstract: Na-beta batteries are an attractive technology as a large-scale electrical energy storage for grid applications. However, additional improvements in performance and cost are needed for wide market penetration. To improve cell performance by minimizing polarizations, reduction of electrolyte thickness was attempted using a duplex structure consisting of a thin dense electrolyte layer and a porous support layer. In this paper, the effects of sintering conditions, dense electrolyte thickness, and cell orientation on the flexural strength of duplex BASEs fabricated using a vapor phase approach were investigated. It is shown that sintering at temperatures between 1500 and 1550 °C results in fine grained microstructures and the highest flexural strength after conversion. Increasing thickness of the dense electrolyte has a small impact on flexural strength, while the orientation of load such that the dense electrolyte is in tension instead of compression has major effects on strength for samples with a well-sintered dense electrolyte

  2. Validation of a novel venous duplex ultrasound objective structured assessment of technical skills for the assessment of venous reflux.

    Science.gov (United States)

    Jaffer, Usman; Normahani, Pasha; Lackenby, Kimberly; Aslam, Mohammed; Standfield, Nigel J

    2015-01-01

    Duplex ultrasound measurement of reflux time is central to the diagnosis of venous incompetence. We have developed an assessment tool for Duplex measurement of venous reflux for both simulator and patient-based training. A novel assessment tool, Venous Duplex Ultrasound Assessment of Technical Skills (V-DUOSATS), was developed. A modified DUOSATS was used for simulator training. Participants of varying skill level were invited to viewed an instructional video and were allowed ample time to familiarize with the Duplex equipment. Attempts made by the participants were recorded and independently assessed by 3 expert assessors and 5 novice assessors using the modified V-DUOSATS. "Global" assessment was also done by expert assessors on a 4-point Likert scale. Content, construct, and concurrent validities as well as reliability were evaluated. Content and construct validity as well as reliability were demonstrated. Receiver operator characteristic analysis-established cut points of 19/22 and 21/30 were most appropriate for simulator and patient-based assessment, respectively. We have validated a novel assessment tool for Duplex venous reflux measurement. Further work is required to establish transference validity of simulator training to improve skill in scanning patients. We have developed and validated V-DUOSATS for simulator training. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  3. Molecular detection of infectious bronchitis and Newcastle disease viruses in broiler chickens with respiratory signs using Duplex RT-PCR.

    Science.gov (United States)

    Saba Shirvan, Aylar; Mardani, Karim

    2014-01-01

    Infectious bronchitis (IB) and Newcastle disease (ND) are highly contagious and the most economically important diseases of the poultry affecting respiratory tract and causing economic losses in poultry industry throughout the world. In the present study, the simultaneous detection and differentiation of causative agents of these diseases were investigated using duplex-RT-PCR. RNA was extracted from vaccinal and reference strains of infectious bronchitis virus (IBV) and Newcastle disease virus (NDV) and then cDNA was synthesized. Using two universal primer sets for detection of IBV and NDV, the duplex-RT-PCR was developed. In order to assess the efficiency of the developed duplex RT-PCR, a number of 12 broiler farms with the symptoms of respiratory tract infection was sampled (trachea, lung and kidney were sampled from affected birds suspicious for IBV and NDV infections). After RNA extraction from tissues and cDNA synthesis, the presence of IBV and NDV genome were investigated using duplex-PCR. The results showed that three of twelve examined broiler farms were positive for IBV and two farms were positive for NDV and IBV. The results revealed that the duplex-RT-PCR is a quick and sensitive procedure for simultaneously detecting IBV and NDV in birds with respiratory infections.

  4. Dilution and Ferrite Number Prediction in Pulsed Current Cladding of Super-Duplex Stainless Steel Using RSM

    Science.gov (United States)

    Eghlimi, Abbas; Shamanian, Morteza; Raeissi, Keyvan

    2013-12-01

    Super-duplex stainless steels have an excellent combination of mechanical properties and corrosion resistance at relatively low temperatures and can be used as a coating to improve the corrosion and wear resistance of low carbon and low alloy steels. Such coatings can be produced using weld cladding. In this study, pulsed current gas tungsten arc cladding process was utilized to deposit super-duplex stainless steel on high strength low alloy steel substrates. In such claddings, it is essential to understand how the dilution affects the composition and ferrite number of super-duplex stainless steel layer in order to be able to estimate its corrosion resistance and mechanical properties. In the current study, the effect of pulsed current gas tungsten arc cladding process parameters on the dilution and ferrite number of super-duplex stainless steel clad layer was investigated by applying response surface methodology. The validity of the proposed models was investigated by using quadratic regression models and analysis of variance. The results showed an inverse relationship between dilution and ferrite number. They also showed that increasing the heat input decreases the ferrite number. The proposed mathematical models are useful for predicting and controlling the ferrite number within an acceptable range for super-duplex stainless steel cladding.

  5. Non destructive method to follow the phase sigma in a duplex stainless steel; Metodologia nao destrutiva para acompanhamento da fase sigma, em um aco inoxidavel duplex

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.M.; Andrade, A.L.S. Souza; Fialho, W.M.L.; Araujo, B.R., E-mail: edgard@ifpb.edu.br [Instituto Federal de Educacao Ciencia e Tecnologia da Paraiba (IFPB), Joao Pessoa, PB (Brazil); Silva, J.H.R.; Leite, Josinaldo P.; Silva, Eloy M. [Instituto Federal de Educacao Ciencia e Tecnologia do Ceara (IFCE), CE (Brazil); Leite, Joao P. [Universidade Federal da Paraiba (UFPB), PB (Brazil)

    2014-07-01

    Duplex stainless steels are subject to embrittlement due to the formation of sigma phase, which is one with the greatest effect of weakening because they are rich in chromium and deplete the matrix of this element. In this paper, a non-destructive methodology based on measurements of Hall voltage, is presented for monitoring the formation of sigma phase at temperatures of 800 deg C and 900 deg C. Different field intensities are generated by an electromagnet and the flow of field lines is detected by a Hall effect sensor. Hall voltage measurements are proportional to the formation of sigma phase generated by different times of aging methods. The results are correlated with results of microscopic, hardness and X-ray diffraction. It was showed that exist a correlation between the Hall voltage and the amount of sigma phase. The formation of this phase influences the signal voltage by reducing the voltage. (author)

  6. Some pitfalls in welding of duplex stainless steels Algumas armadilhas na soldagem de aços inoxidáveis duplex

    Directory of Open Access Journals (Sweden)

    Demian J. Kotecki

    2010-12-01

    Full Text Available Duplex stainless steels (DSS, including super duplex stainless steels {SDSS} have proven to be very useful engineering materials, albeit with somewhat different welding requirements than those of the more familiar austenitic stainless steels. Despite a generally good track record in welding of duplex stainless steels, certain pitfalls have been encountered with enough frequency that they deserve review. Inappropriate base metal specification often leads to unsuitable heat affected zone (HAZ properties. Autogenous fusion zones are also of concern. This issue centers around nitrogen limits. The most frequently encountered is applying the UNS S31803 composition for 2205 DSS, instead of the S32205 composition. Inappropriate welding heat input arises most frequently with SDSS. While 0.5 to 1.5 kJ/mm is a normal heat input recommendation for SDSS, either a root pass or many small beads towards the low end of this heat input range tends to result in precipitation and/or secondary austenite formation in weld metal subjected to repeated thermal cycles from multiple weld passes. Inappropriate PWHT occurs when the enhanced nickel filler metals (typically 9% Ni are used. DSS are not normally given PWHT, but extensive forming of heads, for example, or repair welding of castings, may require a postweld anneal. Specifications such as ASTM A790 and A890 call for annealing at 1040ºC minimum, and the fabricator tends to use temperatures close to that minimum. However, the enhanced nickel filler metals require higher temperatures to dissolve sigma phase that forms during heating to the annealing temperature.Aços inoxidáveis duplex (AID, incluindo os aços super duplex, AISD provaram ser materiais de engenharia muito úteis, embora com requerimentos de soldagem em alguma medida diferentes daqueles dos aços inoxidáveis austeníticos mais usuais. Apesar do histórico geralmente bom dos aços inoxidáveis duplex quanto a soldagem, algumas dificuldades têm sido

  7. Reproducibility of duplex ultrasonography and air plethysmography used for the evaluation of chronic venous insufficiency.

    Science.gov (United States)

    Asbeutah, Akram Mahmoud; Riha, Andrea Zdena; Cameron, James Donald; McGrath, Barry Patrick

    2005-04-01

    The purpose of this study was to determine the reproducibility of measurements on duplex ultrasonography (DU) and air plethysmography (APG) in subjects with post-thrombotic syndrome. Duplex ultrasonography and APG were used to measure indices of lower limb venous reflux in 15 limbs with a history of deep vein thrombosis and evidence of venous insufficiency as diagnosed by ultrasonography. Three limbs were in class 0; 4 were in classes 1 to 3; and 8 were in classes 4 to 6, according to clinical, etiologic, anatomic, and pathophysiologic clinical classification. Duplex ultrasonography was performed 3 times on the same day, and venous diameter, area, peak reflux velocity, reflux flow volume, and reflux duration measurements were obtained. Air plethysmography was performed on 2 days, 7 to 10 days apart, with 1 measurement on the first day and 2 measurements on the second day. Values obtained from APG included outflow fraction, venous filling index, ejection fraction, and residual volume fraction. The measurements were performed by a vascular technologist blinded to the previous test results. One-way analysis of variance, the Student paired t test, and Bland-Altman plots were used to examine the statistical differences of the DU and APG parameters for all measurements. The mean coefficient of variation for within-subject measurements of all DU and APG parameters measured was less than 10%. Bland-Altman plots showed that there were no apparent trends with increasing values over a wide range for any of the DU parameters, nor were there any for the APG parameters. Under ideal conditions, when measured by a highly trained technologist, both DU and APG showed satisfactory reproducibility.

  8. Non-thrombotic Abnormalities on Lower Extremity Venous Duplex Ultrasound Examinations

    Directory of Open Access Journals (Sweden)

    Adhikari, Srikar

    2015-03-01

    Full Text Available Introduction: Emergency physician-performed compression ultrasonography focuses primarily on the evaluation of the proximal veins of the lower extremity in patients with suspected deep venous thrombosis (DVT. A detailed sonographic evaluation of lower extremity is not performed. The objective of this study was to determine the prevalence of non-thrombotic findings on comprehensive lower extremity venous duplex ultrasound (US examinations performed on emergency department (ED patients. Methods: We performed a retrospective six-year review of an academic ED’s records of adult patients who underwent a comprehensive lower extremity duplex venous US examination for the evaluation of DVT. The entire US report was thoroughly reviewed for non-thrombotic findings. Results: We detected non-thrombotic findings in 263 (11%, 95% CI [9.5-11.9%] patients. Among the non-thrombotic findings, venous valvular incompetence (81, 30% was the most frequent, followed by cyst/mass (41, 15%, lymphadenopathy (33, 12%, phlebitis (12, 4.5%, hematoma (8, 3%, cellulitis (1, 0.3% and other (6, 2.2%. Conclusion: In our study, we detected a variety of non-thrombotic abnormalities on comprehensive lower extremity venous duplex US examinations performed on ED patients. Some of these abnormalities could be clinically significant and potentially be detected with point-of-care lower extremity US examinations if the symptomatic region is evaluated. In addition to assessment of the proximal veins for DVT, we recommend sonographic evaluation of the symptomatic area in the lower extremity when performing point-of-care ultrasound examinations to identify non-thrombotic abnormalities that may require immediate intervention or close follow up. [West J Emerg Med. 2015;16(2:250–254.

  9. Mechanism of duplex DNA destabilization by RNA-guided Cas9 nuclease during target interrogation.

    Science.gov (United States)

    Mekler, Vladimir; Minakhin, Leonid; Severinov, Konstantin

    2017-05-23

    The prokaryotic clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) endonuclease cleaves double-stranded DNA sequences specified by guide RNA molecules and flanked by a protospacer adjacent motif (PAM) and is widely used for genome editing in various organisms. The RNA-programmed Cas9 locates the target site by scanning genomic DNA. We sought to elucidate the mechanism of initial DNA interrogation steps that precede the pairing of target DNA with guide RNA. Using fluorometric and biochemical assays, we studied Cas9/guide RNA complexes with model DNA substrates that mimicked early intermediates on the pathway to the final Cas9/guide RNA-DNA complex. The results show that Cas9/guide RNA binding to PAM favors separation of a few PAM-proximal protospacer base pairs allowing initial target interrogation by guide RNA. The duplex destabilization is mediated, in part, by Cas9/guide RNA affinity for unpaired segments of nontarget strand DNA close to PAM. Furthermore, our data indicate that the entry of double-stranded DNA beyond a short threshold distance from PAM into the Cas9/single-guide RNA (sgRNA) interior is hindered. We suggest that the interactions unfavorable for duplex DNA binding promote DNA bending in the PAM-proximal region during early steps of Cas9/guide RNA-DNA complex formation, thus additionally destabilizing the protospacer duplex. The mechanism that emerges from our analysis explains how the Cas9/sgRNA complex is able to locate the correct target sequence efficiently while interrogating numerous nontarget sequences associated with correct PAMs.

  10. Materials Integrity Analysis for Application of Hyper Duplex Stainless Steels to Korean Nuclear Power Plants

    International Nuclear Information System (INIS)

    Chang, Hyun Young; Park, Heung Bae; Park, Yong Soo; Kim, Soon Tae; Kim, Young Sik; Kim, Kwang Tae; Jhang, Yoon Young

    2010-01-01

    Hyper duplex stainless steels have been developed in Korea for the purpose of application to the seawater system of Korean nuclear power plants. This system supplies seawater to cooling water heat exchanger tubes, related pipes and chlorine injection system. In normal operation, seawater is supplied to heat exchanger through the exit of circulating water pump headers, and the heat exchanged sea water is extracted to the discharge pipes in circulating water system connected to the circulating water discharge lines. The high flow velocity of some part of seawater system in nuclear power plants accelerates damages of components. Therefore, high strength and high corrosion resistant steels need to be applied for this environment. Hyper duplex stainless steel (27Cr-7.0Ni-2.5Mo-3.2W-0.35N) has been newly developed in Korea and is being improved for applying to nuclear power plants. In this study, the physical and mechanical properties and corrosion resistance of newly developed materials are quantitatively evaluated in comparative to commercial stainless steels in other countries. The properties of weld and HAZ (heat affected zone) are analyzed and the best compositions are suggested. The optimum conditions in welding process are derived for ensuring the volume fraction of ferrite(α) and austenite(γ) in HAZ and controlling weld cracks. For applying these materials to the seawater heat exchanger, CCT and CPT in weldments are measured. As a result of all experiments, it was found that the newly developed hyper duplex stainless steel WREMBA has higher corrosion resistance and mechanical properties than those of super austenitic stainless steels including welded area. It is expected to be a promising material for seawater systems of Korean nuclear power plants

  11. Mg2+ Effect on Argonaute and RNA Duplex by Molecular Dynamics and Bioinformatics Implications

    Science.gov (United States)

    Nam, Seungyoon; Ryu, Hyojung; Son, Won-joon; Kim, Yon Hui; Kim, Kyung Tae; Balch, Curt; Nephew, Kenneth P.; Lee, Jinhyuk

    2014-01-01

    RNA interference (RNAi), mediated by small non-coding RNAs (e.g., miRNAs, siRNAs), influences diverse cellular functions. Highly complementary miRNA-target RNA (or siRNA-target RNA) duplexes are recognized by an Argonaute family protein (Ago2), and recent observations indicate that the concentration of Mg2+ ions influences miRNA targeting of specific mRNAs, thereby modulating miRNA-mRNA networks. In the present report, we studied the thermodynamic effects of differential [Mg2+] on slicing (RNA silencing cycle) through molecular dynamics simulation analysis, and its subsequent statistical analysis. Those analyses revealed different structural conformations of the RNA duplex in Ago2, depending on Mg2+ concentration. We also demonstrate that cation effects on Ago2 structural flexibility are critical to its catalytic/functional activity, with low [Mg2+] favoring greater Ago2 flexibility (e.g., greater entropy) and less miRNA/mRNA duplex stability, thus favoring slicing. The latter finding was supported by a negative correlation between expression of an Mg2+ influx channel, TRPM7, and one miRNA’s (miR-378) ability to downregulate its mRNA target, TMEM245. These results imply that thermodynamics could be applied to siRNA-based therapeutic strategies, using highly complementary binding targets, because Ago2 is also involved in RNAi slicing by exogenous siRNAs. However, the efficacy of a siRNA-based approach will differ, to some extent, based on the Mg2+ concentration even within the same disease type; therefore, different siRNA-based approaches might be considered for patient-to-patient needs. PMID:25330448

  12. Carotid Consensus Panel duplex criteria can replace modified University of Washington criteria without affecting accuracy.

    Science.gov (United States)

    Kim, Ann H; Augustin, Gener; Shevitz, Andrew; Kim, Hannah; Trivonovich, Michael R; Powell, Alexis R; Kumins, Norman; Tarr, Robert; Kashyap, Vikram S

    2018-04-01

    The decision to intervene for internal carotid stenosis often depends on the degree of stenosis seen on duplex ultrasound (US). The aim of this study is to compare the diagnostic accuracy of two criteria: modified University of Washington (UW) and 2003 Carotid Consensus Panel (CCP). All patients undergoing US in an accredited (IAC) vascular laboratory from January 2010 to June 2015 were reviewed ( n=18,772 US exams). Patients receiving a neck computed tomography angiography (CTA) within 6 months of the US were included in the study ( n=254). The degree of stenosis was determined by UW/CCP criteria and confirmed on CTA images using North American Symptomatic Carotid Endarterectomy Trial (NASCET)/European Carotid Surgery Trial (ECST) schema. Kappa analysis with 95% confidence intervals (CIs) were utilized to determine duplex-CTA agreement. A total of 417 carotid arteries from 221 patients were assessed in this study. The modified UW criteria accurately classified 266 (63.9%, kappa = 0.321, 95% CI 0.255 to 0.386) cases according to NASCET-derived measurements. The sensitivity, specificity, and accuracy at ≥ 60% stenosis were 65.7%, 81.3%, and 81.9%. The CCP criteria resulted in 296 (70.9%) accurate diagnoses (kappa = 0.359, 95% CI 0.280 to 0.437). At ≥ 70% stenosis, the sensitivity, specificity and accuracy were 38.8%, 91.6%, and 87.1% for NASCET. Comparison of the duplex results to ECST-derived CTA measurements revealed a similar trend (UW 53.1%, κ = 0.301 vs CCP 62.1%, κ = 0.315). The CCP criteria demonstrate a higher concordance rate with measurements taken from CTAs. The CCP criteria may be more sensitive in classifying clinically significant degrees of stenosis without a loss in diagnostic accuracy.

  13. Effect of laser shock processing on fatigue crack growth of duplex stainless steel

    International Nuclear Information System (INIS)

    Rubio-Gonzalez, C.; Felix-Martinez, C.; Gomez-Rosas, G.; Ocana, J.L.; Morales, M.; Porro, J.A.

    2011-01-01

    Research highlights: → LSP is an effective surface treatment to improve fatigue properties of duplex stainless steel. → Increasing pulse density, fatigue crack growth rate is reduced. → Microstructure is not affected by LSP. → Compressive residual stresses increases increasing pulse density. - Abstract: Duplex stainless steels have wide application in different fields like the ship, petrochemical and chemical industries that is due to their high strength and excellent toughness properties as well as their high corrosion resistance. In this work an investigation is performed to evaluate the effect of laser shock processing on some mechanical properties of 2205 duplex stainless steel. Laser shock processing (LSP) or laser shock peening is a new technique for strengthening metals. This process induces a compressive residual stress field which increases fatigue crack initiation life and reduces fatigue crack growth rate. A convergent lens is used to deliver 2.5 J, 8 ns laser pulses by a Q-switched Nd:YAG laser, operating at 10 Hz with infrared (1064 nm) radiation. The pulses are focused to a diameter of 1.5 mm. Effect of pulse density in the residual stress field is evaluated. Residual stress distribution as a function of depth is determined by the contour method. It is observed that the higher the pulse density the greater the compressive residual stress. Pulse densities of 900, 1600 and 2500 pul/cm 2 are used. Pre-cracked compact tension specimens were subjected to LSP process and then tested under cyclic loading with R = 0.1. Fatigue crack growth rate is determined and the effect of LSP process parameters is evaluated. In addition fracture toughness is determined in specimens with and without LSP treatment. It is observed that LSP reduces fatigue crack growth and increases fracture toughness if this steel.

  14. Role of Austenite in Brittle Fracture of Bond Region of Super Duplex Stainless Steel

    Science.gov (United States)

    Kitagawa, Yoshihiko; Ikeuchi, Kenji; Kuroda, Toshio

    Weld simulation of heat-affected zone (HAZ) was performed to investigate the mechanism by which austenite affects the toughness of super duplex stainless steel. Thermal cycles of various peak temperatures in the range from 1373 K to 1673 K corresponding to the HAZ were applied to SAF2507 super duplex stainless steel specimens. Charpy impact test was carried out using the specimens after the weld simulation, and the fracture surfaces were observed by SEM using three-dimensionally reconstruction technique. Austenite content decreased with increasing the peak temperature when the peak temperature exceeded 1473 K and the impact value decreased with increasing the peak temperature and decreasing the austenite content. The thermal cycle of the peak temperature of 1673 K corresponding to weld bond region caused decreasing of austenite content which was 22% lower than that of the base metal. The ductile-brittle transition temperature was measured. As a result the temperature increased rapidly in the weld bond region, the peak temperature of which exceeded 1623 K by the grain growth of ferrite matrix occurring subsequently to the completely dissolution of austenite. The morphology of the fracture surfaces after impact testing at 77 K showed cleavage fracture of ferrite. The {100} orientations of cleavage fracture facets were measured using three-dimensional images of the fracture surfaces and the results were visualized as the orientation color maps. The results showed that there were cleavage fractures consisting of a few facets parallel to each other. It was considered that a few facets existed in one ferrite grain. It was concluded that Widmanstätten austenite divided the large fracture into smaller cleavage facets in a ferrite grain and then suppressed the degradation of bond toughness of duplex stainless steel.

  15. Corrosion behaviour of hyper duplex stainless steel in various metallurgical conditions for sea water cooled condensers

    International Nuclear Information System (INIS)

    Singh, Umesh Pratap; Kain, Vivekanand; Chandra, Kamlesh

    2011-01-01

    The sea water cooled condensers have to resist severe corrosion as marine environment is the most corrosive natural environment. Copper alloys are being phased out due to difficulties in water chemistry control and Titanium base alloys are extremely expensive. Austenitic stainless steels (SS) remain prone to localized corrosion in marine environments hence not suitable. These heat exchangers operate at temperatures not exceeding 50 deg C and at very low pressures. The tubes of these heat exchangers are joined to the carbon steel tube sheets by roll expansion or by roll expansion followed by seam welding. These conditions are expected to affect the localized corrosion resistance of the tube in roll joined region due to cold working and in the tube-tube sheet welded joint due to thermal effects of welding. In this study, the localized corrosion behaviour of a Hyper Duplex Stainless Steel (HDSS) has been evaluated, and compared with other materials e.g. types 304L SS, 316L SS, Duplex SS 2205, Titanium grade - 2, and Al Brass. The evaluation is done in three metallurgical conditions (a) as received, (b) cold rolled and (c) welded condition in synthetic sea water at room temperature and at 50 deg C to assess the resistance to crevice, pitting and stress corrosion cracking using standard ASTM exposure and electrochemical techniques. The results provide comparative assessment of these alloys and show their susceptibility in the three metallurgical conditions as encountered in condensers. Hyper-duplex SS has been shown to be highly resistant in sea water for the condenser tubing application. (author)

  16. Full-duplex transmission of IEEE 802.11ac-compliant MIMO WLAN signals over a 2-km 7-core fiber

    NARCIS (Netherlands)

    Fan, Yuting; Li, Jianqiang; Lei, Yi; Tang, Ming; Yin, Feifei; Dai, Yitang; Xu, Kun

    2017-01-01

    In this Letter, we experimentally demonstrate a full-duplex transmission system of IEEE 802.11ac-compliant multiple-input multiple-output (MIMO) signals over a 2-km 7-core fiber for in-building wireless local-area network (WLAN) distributed antenna systems. For full-duplex 3 � 3 MIMO

  17. Summary receiver operating characteristic curves as a technique for meta-analysis of the diagnostic performance of duplex ultrasonography in peripheral arterial disease

    NARCIS (Netherlands)

    deVries, SO; Hunink, MGM; Polak, JF

    Rationale and Objectives. We summarized and compared the diagnostic performance of duplex and color-guided duplex ultrasonography in the evaluation of peripheral arterial disease. We present our research as an example of the use of summary receiver operating characteristic (ROC) curves in a

  18. A study on the effect of solution heat treatment on the corrosion resistance of super duplex stainless steels

    International Nuclear Information System (INIS)

    Park, Jee Yong; Park, Yong Soo; Kim, Soon Tae

    2001-01-01

    High temperature solution heat treatment(typically higher than 1100 .deg. C) is known generally to reduces the resistance to localized corrosion on super duplex stainless. This is attributed to the formation of zone depleted of alloying elements. In this study, the corrosion properties were investigated on super duplex stainless steels with various solution heat treatments. The corrosion resistance of these steels was evaluated in terms of critical pitting temperature and cyclic potentiodynamic polarization test. Chemical composition of the austenite and ferrite phases were analyzed by SEM-EDS. The following results were obtained. (1) By conducting furnace cooling, critical pitting temperature and repassivation potential increased. (2) By omitting furnace cooling, solution heat treatment produced Cr and Mo depleted zone in the phase boundary. (3) During furnace cooling, Cr and Mo rediffused through the phase boundary. This increased the corrosion resistance of super duplex stainless steels

  19. Process for stabilizing dimensions of duplex stainless steels for service at elevated temperatures

    Science.gov (United States)

    Hull, Frederick C.; Tobin, John C.

    1981-01-01

    Duplex stainless steel materials containing austenite plus delta ferrite, are dimensionally stabilized by heating the material to a reaction temperature between about 1050.degree.-1450.degree. F. (566.degree.-788.degree. C.), holding it at this temperature during transformation of delta ferrite to austenite plus sigma phase, and subsequently heating to a reversion temperature between about 1625.degree.-1750.degree. F. (885.degree.-954.degree. C.), whereby the sigma phase transforms back to ferrite, but the austenite remains dispersed in the ferrite phase. Final controlled cooling permits transformation of ferrite to austenite plus sigma and, later, precipitation of carbides.

  20. Relationship between hydrogen-induced phase transformations and pitting nucleation sites in duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Liqiu; Yang, Binjie; Qin, Sixiao [University of Science and Technology Beijing (China). Corrosion and Protection Center

    2016-02-15

    This paper demonstrates the hydrogen-induced phase transformation and the associated pitting nucleation sites of 2507 duplex stainless steel using scanning Kelvin probe force microscopy and magnetic force microscopy. The low potential sites in Volta potential images, which are considered as the pitting nucleation sites, are strongly dependent on the hydrogen-induced phase transformation. They firstly initiate on the magnetic martensite laths in the austenite phase or at the ferrite/austenite boundaries, and then appear near the needle-shaped microtwins in the ferrite phase, because of the difference in physicochemical properties of hydrogen-induced phase transformation microstructures.

  1. Impact of Transport Control Protocol on Full Duplex Performance in 5G Networks

    DEFF Research Database (Denmark)

    Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

    2016-01-01

    Full duplex (FD) communication has attracted the attention of the industry and the academia as an important feature in the design of the future 5th generation (5G) wireless communication system. Such technology allows a device to simultaneously transmit and receive in the same frequency band......, which comes at the price of increased delay and reduced system throughput. FD is expected to accelerate the TCP congestion control mechanism and hence mitigate such consequences. System level results show that FD can outperform HD and alleviate the TCP drawbacks when the inter-cell interference...

  2. Systematic Network Coding with the Aid of a Full-Duplex Relay

    DEFF Research Database (Denmark)

    Giacaglia, Giuliano; Shi, Xiaomeng; Kim, MinJi

    2013-01-01

    is to deliver a given number of data packets to a receiver with the aid of a relay. The source broadcasts to both the receiver and the relay using one frequency, while the relay uses another frequency for transmissions to the receiver, allowing for a full-duplex operation of the relay. We analyze the decoding...... complexity and delay performance of two types of relays: one that preserves the systematic structure of the code from the source; another that does not. A systematic relay forwards uncoded packets upon reception, but transmits coded packets to the receiver after receiving the first coded packet from...

  3. Investigation of selected surface integrity features of duplex stainless steel (DSS after turning

    Directory of Open Access Journals (Sweden)

    G. Krolczyk

    2015-01-01

    Full Text Available The article presents surface roughness profiles and Abbott - Firestone curves with vertical and amplitude parameters of surface roughness after turning by means of a coated sintered carbide wedge with a coating with ceramic intermediate layer. The investigation comprised the influence of cutting speed on the selected features of surface integrity in dry machining. The material under investigation was duplex stainless steel with two-phase ferritic-austenitic structure. The tests have been performed under production conditions during machining of parts for electric motors and deep-well pumps. The obtained results allow to draw conclusions about the characteristics of surface properties of the machined parts.

  4. Microhardness changes gradient of the duplex stainless steel (DSS surface layer after dry turning

    Directory of Open Access Journals (Sweden)

    G. Krolczyk

    2014-10-01

    Full Text Available The article presents the gradient of microhardness changes as a function of the distance from the material surface after turning with a wedge provided with a coating with a ceramic intermediate layer. The investigation comprised the influence of cutting speed on surface integrity microhardness in dry machining. The tested material was duplex stainless steel (DSS with two-phase, ferritic-austenitic structure. The tests have been performed under production conditions during machining of parts for electric motors and deep-well pumps.

  5. Antenna Selection for Full-Duplex MIMO Two-Way Communication Systems

    KAUST Repository

    Wilson-Nunn, Daniel; Chaaban, Anas; Sezgin, Aydin; Alouini, Mohamed-Slim

    2017-01-01

    Antenna selection for full-duplex communication between two nodes, each equipped with a predefined number of antennae and transmit/receive chains, is studied. Selection algorithms are proposed based on magnitude, orthogonality, and determinant criteria. The algorithms are compared to optimal selection obtained by exhaustive search as well as random selection, and are shown to yield performance fairly close to optimal at a much lower complexity. Performance comparison for a Rayleigh fading symmetric channel reveals that selecting a single transmit antenna is best at low signal-to-noise ratio (SNR), while selecting an equal number of transmit and receive antennae is best at high SNR.

  6. Fracture resistance of cracked duplex stainless steel elbows under bending with or without internal pressure

    International Nuclear Information System (INIS)

    Semete, P.; Le Delliou, P.; Ignaccolo, S.

    1997-12-01

    EDF, in co-operation with Framatome, has conducted a research program on the fracture behaviour of aged cast duplex stainless steel elbows. One important task of this program consisted of testing three large diameter (580 mm O.D.) aged cast elbows, which are 2/3-scale models of PWR primary loop elbows. Furthermore, detailed finite element analyses of those three tests were conducted in order to be compared with experimental results. The results of this research program are presented. (K.A.)

  7. Microstructures of cast-duplex stainless steel after long-term aging

    International Nuclear Information System (INIS)

    Chung, H.M.; Chopra, O.K.

    1985-10-01

    Microstructures of cast-duplex stainless steels subjected to long-term aging either in the laboratory or during in-reactor service have been characterized and compared by TEM, SEM, and optical microscopy. The microstructural characteristics have been correlated with the impact failure behavior of the material. G-phase, α', and an unidentified Type X precipitate were responsible for the ferrite-phase embrittlement. Precipitation of M 23 C 6 carbides on austenite-ferrite boundaries further degraded the reactor-aged material

  8. Correlation between nuclear perfusion parameters and duplex US indices in the diagnosis of renal allograft rejection

    International Nuclear Information System (INIS)

    Kim, E.E.; Maklad, N.F.; Pjura, G.A.; Lowry, P.A.

    1986-01-01

    Fifty nuclear perfusion and duplex US studies in 30 patients who had received renal allografts were prospectively analyzed to evaluate their respective measures of blood flow as indicators of rejection. The nuclear study (Tc-99m DTPA) generated three parameters, and a real-time, pulsed Doppler sector scanner generated resistance and pulsatility indices. In nine cases with a greater than 70% resistance index and 1.4 pulsatility index on US, the US findings correlated well with changes in nuclear perfusion parameters, indication rejection. The authors conclude that the combination of decreasing nuclear perfusion parameters and positive US indices may obviate the need for biopsy in the diagnosis of allograft rejection

  9. Towards a phase field model of the microstructural evolution of duplex steel with experimental verification

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Voorhees, P.W.; Lauridsen, Erik Mejdal

    2012-01-01

    A phase field model to study the microstructural evolution of a polycrystalline dual-phase material with conserved phase fraction has been implemented, and 2D simulations have been performed. For 2D simulations, the model predicts the cubic growth well-known for diffusion-controlled systems. Some...... interphase boundaries are found to show a persistent non-constant curvature, which seems to be a feature of multi-phase materials. Finally, it is briefly outlined how this model is to be applied to investigate microstructural evolution in duplex steel. © (2012) Trans Tech Publications, Switzerland....

  10. Decoupling of TX and RX antennas in a full-duplex mobile terminal

    DEFF Research Database (Denmark)

    Foroozanfard, Ehsan; Carvalho, Elisabeth De; Pedersen, Gert F.

    2016-01-01

    In this paper, a Full-duplex (FD) antenna system is presented with a high isolation between the TX and RX antennas. The isolation method is based on utilizing balanced antennas to localize the current on the ground plane and single mode excitation of the ground plane with capacitive coupling...... elements. The simulation results show a promising isolation level of 75 dB. User impact investigation on the antenna isolation, antenna matching and efficiency is presented. The isolation level varies from 60 dB to 30 dB in the worst user scenarios. The proposed antenna system can be used in a MISO/SIMO FD...

  11. Study and prediction model on low temperature aging embrittlement in duplex stainless steels

    International Nuclear Information System (INIS)

    Sanchez, L.; Gutierrez-Solana, F.

    1997-01-01

    Within the framework of a general study on low temperature (280-400 degree centigree) aging embrittlement in duplex stainless steels, a relationship has been obtained between aging, measured from ferrite hardness evolution, and bulk materials embrittlement, determined from fracture toughness and fracture impact tests. The existing correlation between the increase in ferrite hardness and its percentage presence in the fracture path supports this relationship and results in the development of a prediction design model which provides the fracture resistance curves, for any aging level, based on the chemical composition and the steel's properties in an unaged state. (Author)

  12. Detection of thermal aging degradation and plastic strain damage for duplex stainless steel using SQUID sensor

    International Nuclear Information System (INIS)

    Otaka, M.; Evanson, S.; Hesegawa, K.; Takaku, K.

    1991-01-01

    An apparatus using a SQUID sensor is developed for nondestructive inspection. The measurements are obtained with the SQUID sensor located approximately 150 mm from the specimen. The degradation of thermal aging and plastic strain for duplex stainless steel is successfully detected independently from the magnetic characterization measurements. The magnetic flux density under high polarizing field is found to be independent of thermal aging. Coercive force increases with thermal aging time. On the other hand, the magnetic flux density under high field increases with the plastic strain. Coercive force is found to be independent of the plastic strain. (author)

  13. Antenna Selection for Full-Duplex MIMO Two-Way Communication Systems

    KAUST Repository

    Wilson-Nunn, Daniel

    2017-03-11

    Antenna selection for full-duplex communication between two nodes, each equipped with a predefined number of antennae and transmit/receive chains, is studied. Selection algorithms are proposed based on magnitude, orthogonality, and determinant criteria. The algorithms are compared to optimal selection obtained by exhaustive search as well as random selection, and are shown to yield performance fairly close to optimal at a much lower complexity. Performance comparison for a Rayleigh fading symmetric channel reveals that selecting a single transmit antenna is best at low signal-to-noise ratio (SNR), while selecting an equal number of transmit and receive antennae is best at high SNR.

  14. Low cycle fatigue characteristics of duplex stainless steel with degradation under pure torsional load

    International Nuclear Information System (INIS)

    Kwon, Jae Do; Park, Joong Cheul

    2002-01-01

    Monotonic torsional and pure torsional low cycle fatigue (LCF) test with artificial degradation were performed on duplex stainless steel (CF8M). CF8M is used in pipes and valves in nuclear reactor coolant system. It was aged at 430 degree C for 3600hrs. Through the monotonic and LCF test, it is found that mechanical properties (i.e., yield strength, strain hardening exponent, strength coefficient etc.) increase and fatigue life (N f ) decreases with degradation of material. The relationship between shear strain amplitude (γ α ) and N f was proposed

  15. The Formation of Martensitic Austenite During Nitridation of Martensitic and Duplex Stainless Steels

    Science.gov (United States)

    Zangiabadi, Amirali; Dalton, John C.; Wang, Danqi; Ernst, Frank; Heuer, Arthur H.

    2017-01-01

    Isothermal martensite/ferrite-to-austenite phase transformations have been observed after low-temperature nitridation in the martensite and δ-ferrite phases in 15-5 PH (precipitation hardening), 17-7 PH, and 2205 (duplex) stainless steels. These transformations, in the region with nitrogen concentrations of 8 to 16 at. pct, are consistent with the notion that nitrogen is a strong austenite stabilizer and substitutional diffusion is effectively frozen at the paraequilibrium temperatures of our experiments. Our microstructural and diffraction analyses provide conclusive evidence for the martensitic nature of these phase transformations.

  16. LMFBR steam generator development: duplex bayonet tube steam generator. Volume II

    International Nuclear Information System (INIS)

    DeFur, D.D.

    1975-04-01

    This report represents the culmination of work performed in fulfillment of ERDA Contract AT(11-1)-2426, Task Agreement 2, in which alternate steam generator designs were developed and studied. The basic bayonet tube generator design previously developed by C-E under AEC Contract AT(11-1)-3031 was expanded by incorporating duplex heat transfer tubes to enhance the unit's overall safety and reliability. The effort consisted of providing and evaluating conceptual designs of the evaporator, superheater and reheater components for a large plant LMFBR steam generator (950 MWt per heat transport loop)

  17. DNA oligonucleotide duplexes containing intramolecular platinated cross-links: energetics, hydration, sequence, and ionic effects.

    Science.gov (United States)

    Kankia, Besik I; Soto, Ana Maria; Burns, Nicole; Shikiya, Ronald; Tung, Chang-Shung; Marky, Luis A

    2002-11-05

    The anticancer activity of cisplatin arises from its ability to bind covalently to DNA, forming primarily intrastrand cross-links to adjacent purine residues; the most common adducts involve d(GpG) (65%) and d(ApG) (25%) intrastrand cross-links. The incorporation of these platinum adducts in a B-DNA helix induces local distortions, causing bending and unwinding of the DNA. In this work, we used temperature-dependent UV spectroscopy to investigate the unfolding thermodynamics, and associated ionic effects, of two sets of DNA decamer duplexes containing either cis-[Pt(NH(3))(2)[d(GpG

  18. Reserch on energy absorption efficiency in full-duplex multi-user broadcast channel

    Directory of Open Access Journals (Sweden)

    JIANG Fengju

    2015-02-01

    Full Text Available This paper studies the user energy scenarios absorption efficiency optimization in multiuser broadcast channel.This paper assumed that the user terminals using full-duplex mode that the user receive uplink energy information and transfer uplink energy at the same time.In this paper,we maximize the minimum user uplink transmit power,when we ensure that each user′s energy absorption efficiency is greater than a threshold value and satisfies the premise of the base station downlink power emission limits.Finally,the simulation results confirm the effectiveness of the proposed algorithm.

  19. Duplex Heterogeneous Nucleation Behavior of Precipitates in C-Mn Steel Containing Sn

    Science.gov (United States)

    Sun, Guilin; Tao, Sufen

    2018-04-01

    The two successive heterogeneous nucleation behaviors of FeSn2-MnS-Al2O3 complex precipitates in ultrahigh Sn-bearing steel were investigated. First, Al2O3 was the nucleation site of the MnS at the end of solidification. Then, FeSn2 nucleated heterogeneously on the MnS particles that nucleated on the Al2O3 particles. The formation sequence of the precipitated phase caused the duplex heterogeneous nucleation to occur consecutively at most twice.

  20. Tooling solutions for sheet metal forming and punching of lean duplex stainless steel

    DEFF Research Database (Denmark)

    Wadman, Boel; Madsen, Erik; Bay, Niels

    2012-01-01

    .4509 and lean duplex EN1.4162 in a production designed for austenitic stainless steels, such as EN1.4301 and 1.4401. The result is a guideline that summarizes how stainless material properties may affect tool degradation, and suggests tool solutions for reduced production disturbances and tool maintenance cost.......For producers of advanced stainless components the choice of stainless material influences not only the product properties, but also the tooling solution for sheet metal stamping. This work describes how forming and punching tools will be affected when introducing the stainless alloys ferritic EN1...

  1. On the High Temperature Deformation Behaviour of 2507 Super Duplex Stainless Steel

    Science.gov (United States)

    Mishra, M. K.; Balasundar, I.; Rao, A. G.; Kashyap, B. P.; Prabhu, N.

    2017-02-01

    High temperature deformation behaviour of 2507 super duplex stainless steel was investigated by conducting isothermal hot compression tests. The dominant restoration processes in ferrite and austenite phases present in the material were found to be distinct. The possible causes for these differences are discussed. Based on the dynamic materials model, processing map was developed to identify the optimum processing parameters. The microstructural mechanisms operating in the material were identified. A unified strain-compensated constitutive equation was established to describe the high temperature deformation behaviour of the material under the identified processing conditions. Standard statistical parameter such as correlation coefficient has been used to validate the established equation.

  2. Secondary Hardening Behavior in Super Duplex Stainless Steels during LCF in Dynamic Strain Ageing Regime

    OpenAIRE

    Chai, Guocai; Andersson, Marcus

    2013-01-01

    Cyclic deformation behaviors in five modified duplex stainless steel S32705 grades have been studied at 20 °C, 200 °C, 250° and 350 °C. The influence of temperature and nitrogen concentration on the occurrence of the second hardening phenomenon, in the stress response curve was focused. An increase in nitrogen concentration can have a positive effect on dynamic strain ageing by increasing the first hardening and also the second hardening behavior during cyclic deformation. Furthermore, an inc...

  3. Effects of Ce, La and Ba addition on the electrochemical behavior of super duplex stainless steels

    International Nuclear Information System (INIS)

    Yoo, Yun-Ha; Choi, Yoon-Seok; Kim, Jung-Gu; Park, Yong-Soo

    2010-01-01

    The effects of rare earth metal (REM: Ce, La) and Ba addition on aqueous corrosion properties of super duplex stainless steels (SDSS) were investigated by electrochemical tests and surface analyses. The results of potentiodynamic test indicated that the passive range increased by the addition of Ce, La, and Ba, indicating increased relative resistance to localized corrosion. The EIS measurements showed that the Ce-La-Ba-bearing alloys exhibited higher R ct and R p values than the Ce-La-Ba-free alloy at the passive and breakdown states. Furthermore, the additions of REMs and Ba together promoted the formation of dense chromium-enriched passive film.

  4. Effect of Preaging Deformation on Aging Characteristics of 2507 Super Duplex Stainless Steel

    Science.gov (United States)

    Mishra, M. K.; Rao, A. G.; Sarkar, R.; Kashyap, B. P.; Prabhu, N.

    2016-02-01

    In the present study, precipitation of sigma (σ) phase was investigated over the temperature range of 700-850 °C in undeformed and deformed (60% cold rolling) samples of 2507 super duplex stainless steel. The fraction of sigma phase formed as a result of the transformation α → σ + γ2 increases with increasing time and temperature. The increase in sigma phase leads to increase in yield strength and decrease in ductility. Preaging deformation leads to accelerated precipitation of sigma phase. The activation energy for sigma phase precipitation in deformed sample is found to be lower than that in undeformed sample.

  5. Development of super duplex stainless steel for water-supply pipe and valve in nuclear plants

    International Nuclear Information System (INIS)

    Park, Chan Jin; Kim, Jun Sick; Kwon, Hyuk Sang; Park, Young Hwan; Lee, Zin Hyung

    2000-01-01

    Austenitic-ferritic duplex stainless steels are very attractive as material for water-supply facilities in atomic power plants where both high mechanical strength and excellent resistance to localized and stress corrosion are required. However, these alloys have a problem to get sensitive to embrittlement when exposed to temperatures of 250 ∼ 1050 deg C. So far, there have been large efforts to improve this alloy. In this paper, a new developed alloy designed to improve not resistance to the embrittlement but also mechanical and corrosion properties compared with existing commercial alloys were introduced with some experimental results. (author)

  6. Surface modification of 17-4PH stainless steel by DC plasma nitriding and titanium nitride film duplex treatment

    International Nuclear Information System (INIS)

    Qi, F.; Leng, Y.X.; Huang, N.; Bai, B.; Zhang, P.Ch.

    2007-01-01

    17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film

  7. The value of 3D-CT angiography and duplex sonography in comparison to arteriography in carotid artery stenoses

    International Nuclear Information System (INIS)

    Link, J.; Mueller-Huelsbeck, S.; Wesner, F.; Hoepfner, M.; Schwarzenberg, H.; Heller, M.

    1997-01-01

    To determine the value of 3D-CT angiography, duplex sonography in comparison to selective digital subtraction angiography for evaluation of carotid artery stenoses. Methods: 30 patients with 51 stenoses of carotid artery underwent 3D-CT angiography, duplex sonography and angiography. Quantification of stenosis was determined according to the NASCET study and categorized into mild (0-29%), moderate (30-69%), severe (70-99%) and occluded (100%). Results: The agreement of 3D-CT angiography with intraarterial digital subtraction angiography (DSA) was 62% (r=0.89; p [de

  8. Experimental and numerical researches of duplex burnishing process in aspect of achieved productive quality of the product

    Science.gov (United States)

    Patyk, Radoslaw; Kukielka, Leon; Kaldunski, Pawel; Bohdal, Lukasz; Chodor, Jaroslaw; Kulakowska, Agnieszka; Kukielka, Krzysztof; Nagnajewicz, Slawomir

    2018-05-01

    The paper presents the results of experimental researches and numerical simulations of the duplex burnishing process. During duplex burnishing process the treatment is carry out in two stages. In the first stage - on the semi-fabrication surface, the regular asperities are embossed with triangular, symmetrical, periodic outline. In the second stage the asperities are burnished (smooth burnishing) till the needed asperities equalized, resulting in a smooth and strengthened surface layer. The implementation of such technology results in receiving of a new surface layer characterized by favorable functional properties, particularly increased resistance to fatigue wear.

  9. Microstructure and corrosion behavior of shielded metal arc-welded dissimilar joints comprising duplex stainless steel and low alloy steel

    Science.gov (United States)

    Srinivasan, P. Bala; Muthupandi, V.; Sivan, V.; Srinivasan, P. Bala; Dietzel, W.

    2006-12-01

    This work describes the results of an investigation on a dissimilar weld joint comprising a boiler-grade low alloy steel and duplex stainless steel (DSS). Welds produced by shielded metal arc-welding with two different electrodes (an austenitic and a duplex grade) were examined for their microstructural features and properties. The welds were found to have overmatching mechanical properties. Although the general corrosion resistance of the weld metals was good, their pitting resistance was found to be inferior when compared with the DSS base material.

  10. Improper Gaussian signaling in full-duplex relay channels with residual self-interference

    KAUST Repository

    Gaafar, Mohamed; Khafagy, Mohammad Galal; Amin, Osama; Alouini, Mohamed-Slim

    2016-01-01

    We study the potential employment of improper Gaussian signaling (IGS) in full-duplex cooperative settings with residual self-interference (RSI). IGS is recently shown to outperform traditional proper Gaussian signaling (PGS) in several interference-limited channel settings. In this work, IGS is employed in an attempt to alleviate the RSI adverse effect in full-duplex relaying (FDR). To this end, we derive a tight upper bound expression for the end-to-end outage probability in terms of the relay signal parameters represented in its power and circularity coefficient. We further show that the derived upper bound is either monotonic or unimodal in the relay's circularity coefficient. This result allows for easily locating the global optimal point using known numerical methods. Based on the analysis, IGS allows FDR systems to operate even with high RSI. It is shown that, while the communication totally fails with PGS as the RSI increases, the IGS outage probability approaches a fixed value that depends on the channel statistics and target rate. The obtained results show that IGS can leverage higher relay power budgets than PGS to improve the performance, meanwhile it relieves its RSI impact via tuning the signal impropriety. © 2016 IEEE.

  11. Effects of solution treatment on mechanical properties and corrosion resistance of 4A duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Panpan; Wang, Aiqin; Wang, Wenyan [Henan Univ. of Science and Technology, Luoyang (China). School of Material Science and Engineering; Xie, Jingpei [Henan Univ. of Science and Technology, Luoyang (China). Collaborative Innovation Center of Nonferrous Metals

    2018-02-15

    In this study, 4A duplex stainless steels were prepared via remelting in an intermediate frequency furnace and subsequently solution treated at different temperatures. The effects of solution treatment on the mechanical properties and corrosion resistance of 4A duplex stainless steel were investigated. Microstructures were characterized via optical microscopy and scanning electron microscopy. The mechanical properties were evaluated via hardness test, tensile test, and impact test experiments. The point corrosion resistance was studied via chemical immersion and potentiodynamic anodic polarization. The results showed that with increasing solution temperature in the range of 1223 - 1423 K, the tensile strength and hardness first decreased and then increased, and minimum values were obtained at 1323 K. The σ phase precipitated at the boundaries of the α/γ phases in samples solution treated at 1223 K, decreasing both impact energy and pitting potential of the experimental steels. When experimental steels were solution treated at 1373 K for 2 h, a suitable volume fraction of α/γ was uniformly distributed throughout the microstructure, and the steels exhibited optimal mechanical properties and pitting corrosion resistance.

  12. Unstable Hoogsteen base pairs adjacent to echinomycin binding sites within a DNA duplex

    International Nuclear Information System (INIS)

    Gilbert, D.E.; van der Marel, G.A.; van Boom, J.H.; Feigon, J.

    1989-01-01

    The bisintercalation complex present between the DNA octamer [d(ACGTACGT)] 2 and the cyclic octadepsipeptide antibiotic echinomycin has been studied by one- and two-dimensional proton NMR, and the results obtained have been compared with the crystal structures of related DNA-echinomycin complexes. Two echinomycins are found to bind cooperatively to each DNA duplex at the CpG steps, with the two quinoxaline rings of each echinomycin bisintercalating between the C·G and A·T base pairs. At low temperatures, the A·T base pairs on either side of the intercalation site adopt the Hoogsteen conformation, as observed in the crystal structures. However, as the temperature is raised, the Hoogsteen base pairs in the interior of the duplex are destabilized and are observed to be exchanging between the Hoogsteen base pair and either an open or a Watson-Crick base-paired state. The terminal A·T base pairs, which are not as constrained by the helix as the internal base pairs, remain stably Hoogsteen base-paired up to at least 45 degree C. The implications of these results for the biological role of Hoogsteen base pairs in echinomycin-DNA complexes in vivo are discussed

  13. Improper Gaussian signaling in full-duplex relay channels with residual self-interference

    KAUST Repository

    Gaafar, Mohamed

    2016-07-26

    We study the potential employment of improper Gaussian signaling (IGS) in full-duplex cooperative settings with residual self-interference (RSI). IGS is recently shown to outperform traditional proper Gaussian signaling (PGS) in several interference-limited channel settings. In this work, IGS is employed in an attempt to alleviate the RSI adverse effect in full-duplex relaying (FDR). To this end, we derive a tight upper bound expression for the end-to-end outage probability in terms of the relay signal parameters represented in its power and circularity coefficient. We further show that the derived upper bound is either monotonic or unimodal in the relay\\'s circularity coefficient. This result allows for easily locating the global optimal point using known numerical methods. Based on the analysis, IGS allows FDR systems to operate even with high RSI. It is shown that, while the communication totally fails with PGS as the RSI increases, the IGS outage probability approaches a fixed value that depends on the channel statistics and target rate. The obtained results show that IGS can leverage higher relay power budgets than PGS to improve the performance, meanwhile it relieves its RSI impact via tuning the signal impropriety. © 2016 IEEE.

  14. Renal duplex doppler ultrasonography in patients with recurrent urinary tract infection

    Directory of Open Access Journals (Sweden)

    Soliman Neveen

    2009-01-01

    Full Text Available Renal hemodynamics were studied using duplex Doppler ultrasonography in forty (33 females and 7 males; mean age: 12.1 ± 5.3 years normotensive patients with recurrent urinary tract infection and with no evidence of obstructive uropathy and age matched control group of 24 healthy children and adolescents. Resistivity index (RI and pulsatility index (PI in both arcuate (AA and interlobar (IA arteries were significantly higher in patients as compared to controls (P= 0.001, 0.01 respectively. Diastolic/systolic ratio (D/S at the same levels of renal vasculature (AA and IA was significantly lower in study patients as compared to their controls (P= 0.01, 0.001 respectively. Moreover, scarred renal units had higher RI and PI values as well as lower D/S ratio as compared to non scarred units (p= 0.01, 0.001, 0.001 respectively.. In conclusion, intra renal vascular resistivity is significantly increased in recurrent UTI patients particularly in those sus-taining renal scarring. Further follow up studies are recommended to determine if duplex assess-ment of intrarenal vasculature could be useful as an ancillary diagnostic and/or prognostic technique in the evaluation and follow up of recurrent UTI.

  15. Spectrum sharing opportunities of full-duplex systems using improper Gaussian signaling

    KAUST Repository

    Gaafar, Mohamed

    2015-08-01

    Sharing the licensed spectrum of full-duplex (FD) primary users (PU) brings strict limitations on the underlay cognitive radio operation. Particularly, the self interference may overwhelm the PU receiver and limit the opportunity of secondary users (SU) to access the spectrum. Improper Gaussian signaling (IGS) has demonstrated its superiority in improving the performance of interference channel systems. Throughout this paper, we assume a FD PU pair that uses proper Gaussian signaling (PGS), and a half-duplex SU pair that uses IGS. The objective is to maximize the SU instantaneous achievable rate while meeting the PU quality-of-service. To this end, we propose a simplified algorithm that optimizes the SU signal parameters, i.e, the transmit power and the circularity coefficient, which is a measure of the degree of impropriety of the SU signal, to achieve the design objective. Numerical results show the merits of adopting IGS compared with PGS for the SU especially with the existence of week PU direct channels and/or strong SU interference channels.

  16. Detection of chicken contamination in beef meatball using duplex-PCR Cyt b gene

    Science.gov (United States)

    Sari, E. P.; Kartikasari, L. R.; Cahyadi, M.

    2017-04-01

    Beef is one of expensive animal protein sources compared to other meats, on the other hand, chicken is cheap animal protein source. Mixing of chicken into beef meatball is possibly performed to decrease production cost. The aim of this study was to detect chicken contamination in beef meatball using Cytochrome b (Cyt b) gene by duplex-PCR. Sample was designed and prepared as follows, 100% of chicken meatball, 100% of beef meatball and serial level of chicken contaminations in beef meatball (1, 5, 10 and 25%, respectively). Isolation of DNA genome from meatball was according to the guideline of gSYNCTM DNA Extraction Kit for animal tissue. The PCR reaction was carried out using KAPA2G Fast Multiplex Mix. This study found that the DNA genome was succesfully extracted. Moreover, chicken contamination in beef meatball was indicated by the presence of 227 bp DNA band on 2% of agarose gels. Current study revealed that duplex-PCR using Cyt b gene as a genetic marker was able to detect chicken contamination in beef meatball until 1% of chicken meat in the sample. It can be effectively used to identify contamination and also authenticate species origin in animal products to protect consumer from undesirable contents in the food.

  17. Color coded duplex sonography. Interdisciplinary vascular ultrasonography; Farbkodierte Duplexsonographie. Interdisziplinaerer vaskulaerer Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Kubale, R. [Institut fuer Radiologie, Sonographie und Nuklearmedizin, Pirmasens (Germany); Stiegler, H. [Staedtisches Krankenhaus Schwabing, Muenchen (Germany). 7. Medizinische Abt.

    2002-07-01

    An interdisciplinary team of experts impart the state of the art in color coded duplex sonography applied for examination of all anatomic areas. Detailed information is given for every vascular area, describing the examination procedure, possible origins of mistakes or faults, and means to avoid them. In addition to the classical applications, eg. for examination of the extra- and intracranial vessels, vessels of the limbs, visceral vessels and the vessels of liver and kidney, there are chapters devoted to: haemodialysis shunts, arteriovenous malformations, duplex sonography of the penis, tumor vascularisation. (orig./CB) [German] Ein interdisziplinaeres Autorenteam vermittelt Ihnen den State of the Art der FKDS fuer alle anatomischen Regionen. Fuer jede der Gefaessregionen werden detaillierte Angaben zum Untersuchungsablauf, zu moeglichen Fehlerquellen und zu deren Vermeidung geboten. Neben den klassischen Anwendungen bei der Untersuchung - der extra- und intrakraniellen Gefaesse, - der Extremitaetengefaesse, - der viszeralen Gefaesse sowie der Gefaesse von Niere und Leber finden Sie Kapitel zu den Themen: Haemodialyseshunt, arteriovenoese Malformationen, Duplexsonographie des Penis und Tumorvaskularisation. (orig./AJ)

  18. Artificial neural network aided non-invasive grading evaluation of hepatic fibrosis by duplex ultrasonography

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2012-06-01

    Full Text Available Abstract Background Artificial neural networks (ANNs are widely studied for evaluating diseases. This paper discusses the intelligence mode of an ANN in grading the diagnosis of liver fibrosis by duplex ultrasonogaphy. Methods 239 patients who were confirmed as having liver fibrosis or cirrhosis by ultrasound guided liver biopsy were investigated in this study. We quantified ultrasonographic parameters as significant parameters using a data optimization procedure applied to an ANN. 179 patients were typed at random as the training group; 60 additional patients were consequently enrolled as the validating group. Performance of the ANN was evaluated according to accuracy, sensitivity, specificity, Youden’s index and receiver operating characteristic (ROC analysis. Results 5 ultrasonographic parameters; i.e., the liver parenchyma, thickness of spleen, hepatic vein (HV waveform, hepatic artery pulsatile index (HAPI and HV damping index (HVDI, were enrolled as the input neurons in the ANN model. The sensitivity, specificity and accuracy of the ANN model for quantitative diagnosis of liver fibrosis were 95.0%, 85.0% and 88.3%, respectively. The Youden’s index (YI was 0.80. Conclusions The established ANN model had good sensitivity and specificity in quantitative diagnosis of hepatic fibrosis or liver cirrhosis. Our study suggests that the ANN model based on duplex ultrasound may help non-invasive grading diagnosis of liver fibrosis in clinical practice.

  19. Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA.

    Science.gov (United States)

    Yang, Zhiyu; Price, Nathan E; Johnson, Kevin M; Wang, Yinsheng; Gates, Kent S

    2017-06-20

    Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3'ddR5p) at the 3'-terminus of the strand break. Interestingly, this strand scission process leaves an electrophilic α,β-unsaturated aldehyde residue embedded within the resulting nicked duplex. Here we present evidence that 3'ddR5p derivatives generated by spermine-catalyzed strand cleavage at Ap sites in duplex DNA can react with adenine residues on the opposing strand to generate a complex lesion consisting of an interstrand cross-link adjacent to a strand break. The cross-link blocks DNA replication by ϕ29 DNA polymerase, a highly processive polymerase enzyme that couples synthesis with strand displacement. This suggests that 3'ddR5p-derived cross-links have the potential to block critical cellular DNA transactions that require strand separation. LC-MS/MS methods developed herein provide powerful tools for studying the occurrence and properties of these cross-links in biochemical and biological systems. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  20. Full-Duplex Relaying with Improper Gaussian Signaling over Nakagami-m Fading Channels

    KAUST Repository

    Gaafar, Mohamed

    2017-10-04

    We study the potential employment of improper Gaussian signaling (IGS) in full-duplex relaying (FDR) with non-negligible residual self-interference (RSI) under Nakagami- m fading. IGS is recently shown to outperform traditional proper Gaussian signaling (PGS) in several interference-limited settings. In this work, IGS is employed as an attempt to alleviate RSI. We use two performance metrics, namely, the outage probability and the ergodic rate. First, we provide upper and lower bounds for the system performance in terms of the relay transmit power and circularity coefficient, a measure of the signal impropriety. Then, we numerically optimize the relay signal parameters based only on the channel statistics to improve the system performance. Based on the analysis, IGS allows FDR to operate even with high RSI. The results show that IGS can leverage higher power budgets to enhance the performance, meanwhile it relieves RSI impact via tuning the signal impropriety. Interestingly, one-dimensional optimization of the circularity coefficient, with maximum relay power, offers a similar performance as the joint optimization, which reduces the optimization complexity. From a throughput standpoint, it is shown that IGS-FDR can outperform not only PGS-FDR, but also half-duplex relaying with/without maximum ratio combining over certain regions of the target source rate.

  1. Expanding the action of duplex RNAs into the nucleus: redirecting alternative splicing

    Science.gov (United States)

    Liu, Jing; Hu, Jiaxin; Corey, David R.

    2012-01-01

    Double-stranded RNAs are powerful agents for silencing gene expression in the cytoplasm of mammalian cells. The potential for duplex RNAs to control expression in the nucleus has received less attention. Here, we investigate the ability of small RNAs to redirect splicing. We identify RNAs targeting an aberrant splice site that restore splicing and production of functional protein. RNAs can target sequences within exons or introns and affect the inclusion of exons within SMN2 and dystrophin, genes responsible for spinal muscular atrophy and Duchenne muscular dystrophy, respectively. Duplex RNAs recruit argonaute 2 (AGO2) to pre-mRNA transcripts and altered splicing requires AGO2 expression. AGO2 promotes transcript cleavage in the cytoplasm, but recruitment of AGO2 to pre-mRNAs does not reduce transcript levels, exposing a difference between cytoplasmic and nuclear pathways. Involvement of AGO2 in splicing, a classical nuclear process, reinforces the conclusion from studies of RNA-mediated transcriptional silencing that RNAi pathways can be adapted to function in the mammalian nucleus. These data provide a new strategy for controlling splicing and expand the reach of small RNAs within the nucleus of mammalian cells. PMID:21948593

  2. Sharing the Licensed Spectrum of Full-Duplex Systems Using Improper Gaussian Signaling

    KAUST Repository

    Gaafar, Mohamed

    2015-12-01

    Sharing the spectrum with in-band full-duplex (FD) primary users (PU) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-interference introduced at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. In this work, we attempt to tackle this problem through the use of the so-called improper Gaussian signaling. Such a signaling technique has demonstrated its superiority in improving the overall performance in interference limited networks. Particularly, we assume a system with a SU pair working in half-duplex mode that uses improper Gaussian signaling while the FD PU pair implements the regular proper Gaussian signaling techniques. First, we derive a closed form expression for the SU outage probability and an upper bound for the PU outage probability. Then, we optimize the SU signal parameters to minimize its outage probability while maintaining the required PU quality-of-service based on the average channel state information. Finally, we provide some numerical results that validate the tightness of the PU outage probability bound and demonstrate the advantage of employing the improper Gaussian signaling to the SU in order to access the spectrum of the FD PU.

  3. Duplex Interrogation by a Direct DNA Repair Protein in Search of Base Damage

    Science.gov (United States)

    Yi, Chengqi; Chen, Baoen; Qi, Bo; Zhang, Wen; Jia, Guifang; Zhang, Liang; Li, Charles J.; Dinner, Aaron R.; Yang, Cai-Guang; He, Chuan

    2012-01-01

    ALKBH2 is a direct DNA repair dioxygenase guarding mammalian genome against N1-methyladenine, N3-methylcytosine, and 1,N6-ethenoadenine damage. A prerequisite for repair is to identify these lesions in the genome. Here we present crystal structures of ALKBH2 bound to different duplex DNAs. Together with computational and biochemical analyses, our results suggest that DNA interrogation by ALKBH2 displays two novel features: i) ALKBH2 probes base-pair stability and detects base pairs with reduced stability; ii) ALKBH2 does not have nor need a “damage-checking site”, which is critical for preventing spurious base-cleavage for several glycosylases. The demethylation mechanism of ALKBH2 insures that only cognate lesions are oxidized and reversed to normal bases, and that a flipped, non-substrate base remains intact in the active site. Overall, the combination of duplex interrogation and oxidation chemistry allows ALKBH2 to detect and process diverse lesions efficiently and correctly. PMID:22659876

  4. Flexible Design for α-Duplex Communications in Multi-Tier Cellular Networks

    KAUST Repository

    AlAmmouri, Ahmad

    2016-06-13

    Backward compatibility is an essential ingredient for the success of new technologies. In the context of inband full-duplex (FD) communication, FD base stations (BSs) should support half-duplex (HD) users’ equipment (UEs) without sacrificing the foreseen FD gains. This paper presents flexible and tractable modeling framework for multi-tier cellular networks with FD BSs and FD/HD UEs. The presented model is based on stochastic geometry and accounts for the intrinsic vulnerability of uplink transmissions. The results show that FD UEs are not necessarily required to harvest rate gains from FD BSs. In particular, the results show that adding FD UEs to FD BSs offers a maximum of 5% rate gain over FD BSs and HD UEs case if multi-user diversity is exploited, which is a marginal gain compared to the burden required to implement FD transceivers at the UEs’ side. To this end, we shed light on practical scenarios where HD UEs operation with FD BSs outperforms the operation when both the BSs and UEs are FD and we find a closed form expression for the critical value of the self-interference attenuation power required for the FD UEs to outperform HD UEs.

  5. Optimization of an integrated optic broadband duplexer for 0.8/1.3-micrometer applications

    Science.gov (United States)

    Ghibaudo, Elise; Broquin, Jean-Emmanuel; Benech, Pierre

    2003-06-01

    These last years, the growth of data traffic has increased the interest for broadband integrated optic devices. Their applications include, for example, the fiber communications on a single fiber by adding the transmission capacity of two optical telecommunication windows for Local Area Networks (LAN) and Wide Area Networks (WAN) or by combining pump and signal wavelenghts in rare earth doped intergrated optical amplifiers. A promising technology to realize those devices is ion-exchange on glass. Indeed, it allows the integration of different functions in a glass substrate with efficient results and a better compatibility in fiber systems with a low cost. We propose in this paper an original broadband duplexer based on a leaky structure. First, the physical principle of the component is explained. The core of the structure is a leaky zone which involves a non-resonant coupling and ensures a broadband spectral behavior to the component. Then, the broadband duplexer is presented and the focus is specially made on the improvement of the outputs crosstalk through the suppression of parasitical back reflections. Theoretical optimization and validation by simulations are presented. Finally, perspectives of this work are proposed.

  6. Microtwin formation in the α phase of duplex titanium alloys affected by strain rate

    International Nuclear Information System (INIS)

    Lin, Yi-Hsiang; Wu, Shu-Ming; Kao, Fang-Hsin; Wang, Shing-Hoa; Yang, Jer-Ren; Yang, Chia-Chih; Chiou, Chuan-Sheng

    2011-01-01

    Research highlights: → The long and dense twins in α phase of SP700 alloy occurring at lower strain rates promote a good ductility. → The deformation in SP700 alloy changed to micro twins-controlled mechanism in α as the strain rate decreases. → The material has time to redistribute the deformed strain between α and β as the strain rate decreases. - Abstract: The effect of tensile strain rate on deformation microstructure was investigated in Ti-6-4 (Ti-6Al-4V) and SP700 (Ti-4.5Al-3V-2Mo-2Fe) of the duplex titanium alloys. Below a strain rate of 10 -2 s -1 , Ti-6-4 alloy had a higher ultimate tensile strength than SP700 alloy. However, the yield strength of SP700 was consistently greater than Ti-6-4 at different strain rates. The ductility of SP700 alloy associated with twin formation (especially at the slow strain rate of 10 -4 s -1 ), always exceeded that of Ti-6-4 alloy at different strain rates. It is caused by a large quantity of deformation twins took place in the α phase of SP700 due to the lower stacking fault energy by the β stabilizer of molybdenum alloying. In addition, the local deformation more was imposed on the α grains from the surrounding β-rich grains by redistributing strain as the strain rate decreased in SP700 duplex alloy.

  7. CHARACTERIZATION AND PERFORMANCE OF DUPLEX-COATINGS ON Cr-V COLD WORK TOOL STEEL

    Directory of Open Access Journals (Sweden)

    Peter Jurči

    2015-09-01

    Full Text Available Specimens made of Vanadis 6 steel were heat treated, plasma nitrided and coated with Cr2N. The microstructure, phase constitution and mechanical properties of plasma nitrided areas and duplex-coatings have been investigated using the light microscopy, scanning electron microscopy, X-ray diffraction and microhardness measurements. The adhesion of the coatings and the wear performance were studied using the scratch test and ring-on-plate tribological testing. Worn surfaces were examined by scanning electron microscopy. Nitrided areas formed at lower temperature were free of compound “white” layer while hose developed at higher temperatures contained as the white layer so the nitrided network. Significant increase in substrate hardness was detected due to the nitriding. Beneficial effect of the nitriding on the adhesion of Cr2N coatings was clearly determined whereas the extent in improvement of the adhesion depends on the presence/no presence of “white” layer on the surface. The extent of beneficial effect of plasma nitriding on the wear performance follows the impact of the constitution of nitrided areas on the adhesion. The amelioration of wear performance of Cr2N coatings can be attributed to the supporting effect of hard nitrided intermediate region, which provides excellent resistance of the substrate against plastic deformation, under heavy loading in particular. Practical testing demonstrated many times prolonged service-time of duplex-treated tools for sheet metal working.

  8. Transmission Power Adaption for Full-Duplex Relay-Aided Device-to-Device Communication

    Directory of Open Access Journals (Sweden)

    Hui Dun

    2017-03-01

    Full Text Available Device-to-device (D2D communications bring significant improvements of spectral efficiency by underlaying cellular networks. However, they also lead to a more deteriorative interference environment for cellular users, especially the users in severely deep fading or shadowing. In this paper, we investigate a relay-based communication scheme in cellular systems, where the D2D communications are exploited to aid the cellular downlink transmissions by acting as relay nodes with underlaying cellular networks. We modeled two-antenna infrastructure relays employed for D2D relay. The D2D transmitter is able to transmit and receive signals simultaneously over the same frequency band. Then we proposed an efficient power allocation algorithm for the base station (BS and D2D relay to reduce the loopback interference which is inherent due to the two-antenna infrastructure in full-duplex (FD mode. We derived the optimal power allocation problem in closed form under the independent power constraint. Simulation results show that the algorithm reduces the power consumption of D2D relay to the greatest extent and also guarantees cellular users’ minimum transmit rate. Moreover, it also outperforms the existing half-duplex (HD relay mode in terms of achievable rate of D2D.

  9. Deformation Characteristic and Constitutive Modeling of 2707 Hyper Duplex Stainless Steel under Hot Compression

    Directory of Open Access Journals (Sweden)

    Huabing Li

    2016-09-01

    Full Text Available Hot deformation behavior and microstructure evolution of 2707 hyper duplex stainless steel (HDSS were investigated through hot compression tests in the temperature range of 900–1250 °C and strain rate range of 0.01–10 s−1. The results showed that the flow behavior strongly depended on strain rate and temperature, and flow stress increased with increasing strain rate and decreasing temperature. At lower temperatures, many precipitates appeared in ferrite and distributed along the deformation direction, which could restrain processing of discontinuous dynamic recrystallization (DRX because of pinning grain boundaries. When the temperature increased to 1150 °C, the leading softening behaviors were dynamic recovery (DRV in ferrite and discontinuous DRX in austenite. When the temperature reached 1250 °C, softening behavior was mainly DRV in ferrite. The increase of strain rate was conducive to the occurrence of discontinuous DRX in austenite. A constitutive equation at peak strain was established and the results indicated that 2707 HDSS had a higher Q value (569.279 kJ·mol−1 than other traditional duplex stainless steels due to higher content of Cr, Mo, Ni, and N. Constitutive modeling considering strain was developed to model the hot deformation behavior of 2707 HDSS more accurately, and the correlation coefficient and average absolute relative error were 0.992 and 5.22%, respectively.

  10. Influence of Thermal Aging on Primary Water Stress Corrosion Cracking of Cast Duplex Stainless Steels

    International Nuclear Information System (INIS)

    Yamada, T.; Totsuka, N.; Nakajima, N.; Arioka, K.; Negishi, K.

    2002-01-01

    In order to evaluate the SCC (stress corrosion cracking) susceptibility of cast duplex stainless steels which are used for the main coolant piping material of pressurized water reactors (PWRs), the slow strain rate test (SSRT) and the constant load test (CLT) were performed in simulated PWR primary water at 360 C. The main coolant piping materials contain ferrite phase with ranging from 8 to 23 % and its mechanical properties are affected by long time thermal aging. The 23% ferrite material was prepared for test as the maximum ferrite content of main coolant pipes in Japanese PWRs. The brittle fracture in the non-aged materials after SSRT is mainly caused by quasi-cleavage fracture in austenitic phase. On the other hand, a mixture of quasi-cleavage fracture in austenite and ferrite phases was observed on long time aged material. Also on CLT, (2 times σ y ), after 3,000 hours exposure, microcracks were observed on the surface of non-aged and aged for 10,000 hours at 400 C materials. The crack initiation site of CLT is similar to that of SSRT. The SCC susceptibility of the materials increases with aging time. It is suggested that the ferrite hardening with aging affect SCC susceptibility of cast duplex stainless steels. (authors)

  11. Spinodal decomposition of austenite in long-term-aged duplex stainless steel

    International Nuclear Information System (INIS)

    Chung, H.M.

    1989-02-01

    Spinodal decomposition of austenite phase in the cast duplex stainless steels CF-8 and -8M grades has been observed after long- term thermal aging at 400 and 350/degree/C for 30,000 h (3.4 yr). At 320/degree/C, the reaction was observed only at the limited region near the austenite grain boundaries. Ni segregation and ''worm-holes'' corresponding to the spatial microchemical fluctuations have been confirmed. The decomposition was observed only for heats containing relatively high overall Ni content (9.6--12.0 wt %) but not in low-Ni (8.0--9.4 wt %) heats. In some specimens showing a relatively advanced stage of decomposition, localized regions of austenite with a Vickers hardness of 340--430 were observed. However, the effect of austenite decomposition on the overall material toughness appears secondary for aging up to 3--5 yr in comparison with the effect of the faster spinodal decomposition in ferrite phase. The observation of the thermally driven spinodal decomposition of the austenite phase in cast duplex stainless steels validates the proposition that a miscibility gap occurs in Fe-Ni and ancillary systems. 16 refs., 7 figs., 1 tab

  12. Weldability aspects of a newly developed duplex stainless steel LDX 2101

    Energy Technology Data Exchange (ETDEWEB)

    Westin, E.M. [Avesta Research Centre, Avesta (Sweden). Outokumpu Stainless; Brolund, B. [SSAB Tunnplat, Borlaenge (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Stockholm (Sweden)

    2008-06-15

    Duplex grades have, due to balanced chemical compositions of both filler and base metals, a weldability that allows for successful welding using a majority of the technically relevant techniques of today. In order to fulfil the performance requirements several aspects must be considered. In the heat affected zone (HAZ) the austenite reformation must be reasonably high and in the weld metal the microstructure must be stable so that e.g. high productivity welding and multi-pass welding are possible, without precipitation of detrimental phases in previous passes. This paper addresses the effect of alloying elements and thermal cycles on phase balance in the high temperature HAZ (HTHAZ) of the newly developed lean duplex grade LDX 2101 (EN 1.4162, UNS S32101). Bead-on-plate welds and simulated weld structures have been produced and investigated using metallography, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results are analysed using the thermodynamic database Thermo-Calc and a model for phase transformation based on a paraequilibrium assumption for ferrite-austenite transformation. In the temperature region outside the paraequilibrium domain, growth controlled by diffusion of substitutional elements was considered. The analysis follows a model by Cahn regarding grain boundary nucleated growth and the Hillert-Engberg model on kinetics of spherical and planar growth. (orig.)

  13. Changes in electromagnetic properties during thermal aging of duplex stainless steel

    International Nuclear Information System (INIS)

    Goto, T.; Kamimura, T.; Yamaoka, T.

    1995-01-01

    Cast duplex stainless steels used in primary pressure-boundary components of pressurized water reactors have been found to be susceptible to thermal aging embrittlement at reactor operating temperature. Extensive studies and investigations on the aging mechanism itself have been conducted in order to evaluate end-of-life aging. Three types of testing employing electromagnetic techniques, i.e., electric resistivity testing, coercivity measurement testing and Barkhausen noise testing have been investigated in order to search for an effective nondestructive method to evaluate the thermal aging of cast duplex stainless steels. Changes in impact strength, micro-Vickers hardness of ferrite phase and electromagnetic properties were studied in two CF8M materials with differing ferrite content that were subjected to long-term heating. The values measured using the electromagnetic techniques were correlated with Charpy-impact energy values and the observed microstructural changes were used to assess the potential that these techniques have for use as NDE methods. Each of these techniques was found to be sensitive to different processes that occur during thermal aging. Therefore, an integrated method using these techniques is now under development

  14. Sharing the Licensed Spectrum of Full-Duplex Systems using Improper Gaussian Signaling

    KAUST Repository

    Gaafar, Mohamed; Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2016-01-01

    Sharing the spectrum with in-band full-duplex (FD) primary users (PU) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-inteference introducsed at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. In this work, we attempt to tackle this problem through the use of so called improper Gaussian signaling (IGS). Such a signaling technique has demonstrated its superiority in improving the overall performance in interference limited networks. Particularly, we assume a system with a SU pair working in half-duplex mode that uses IGS while the FD PU pair implements the regular proper Gaussiam signaling techniques. Frist, we derive a closed form expression for the SU outage probability while maintaining the required PU quality-of-service based on the average channel state information. Finally, we provide some numerical results that validate the tightness of the PU outage probability bound and demonstrate the advantage of employing IGS to the SU in order to access the spectrum of the FD PU.

  15. Sharing the Licensed Spectrum of Full-Duplex Systems using Improper Gaussian Signaling

    KAUST Repository

    Gaafar, Mohamed

    2016-01-06

    Sharing the spectrum with in-band full-duplex (FD) primary users (PU) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-inteference introducsed at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. In this work, we attempt to tackle this problem through the use of so called improper Gaussian signaling (IGS). Such a signaling technique has demonstrated its superiority in improving the overall performance in interference limited networks. Particularly, we assume a system with a SU pair working in half-duplex mode that uses IGS while the FD PU pair implements the regular proper Gaussiam signaling techniques. Frist, we derive a closed form expression for the SU outage probability while maintaining the required PU quality-of-service based on the average channel state information. Finally, we provide some numerical results that validate the tightness of the PU outage probability bound and demonstrate the advantage of employing IGS to the SU in order to access the spectrum of the FD PU.

  16. Initiation of the microgene polymerization reaction with non-repetitive homo-duplexes

    International Nuclear Information System (INIS)

    Itsko, Mark; Zaritsky, Arieh; Rabinovitch, Avinoam; Ben-Dov, Eitan

    2008-01-01

    Microgene Polymerization Reaction (MPR) is used as an experimental system to artificially simulate evolution of short, non-repetitive homo-duplex DNA into multiply-repetitive products that can code for functional proteins. Blunt-end ligation by DNA polymerase is crucial in expansion of homo-duplexes (HDs) into head-to-tail multiple repeats in MPR. The propagation mechanism is known, but formation of the initial doublet (ID) by juxtaposing two HDs and polymerization through the gap has been ambiguous. Initiation events with pairs of HDs using Real-Time PCR were more frequent at higher HD concentrations and slightly below the melting temperature. A process molecularity of about 3.1, calculated from the amplification efficiency and the difference in PCR cycles at which propagation was detected at varying HD concentrations, led to a simple mechanism for ID formation: the gap between two HDs is bridged by a third. Considering thermodynamic aspects of the presumed intermediate 'nucleation complex' can predict relative propensity for the process with other HDs

  17. Corrosion behavior of duplex polyaniline/epoxy coating on mild steel in 3% NaCl

    Directory of Open Access Journals (Sweden)

    Gvozdenović Milica M.

    2005-01-01

    Full Text Available The corrosion behavior and thermal stability of epoxy coatings electrodeposited on mild steel and on mild steel with electrochemically deposited polyaniline (PANI film were investigated by electrochemical impedance spectroscopy (EIS and thermo gravimetric analysis (TGA. The aim of the paper was to present new findings on the corrosion protection of mild steel by a duplex PANI/-epoxy coating in 3% NaCI solution and to determine the effect of thin PANI film on the protective properties of the coating. PANI film was deposited electrochemically on mild steel from an aqueous solution of 0.5 mol dm"3 sodium benzoate and 0.1 mol dm"3 aniline at a constant current density of 1.5 mA cm"2. Non-pigmented epoxy coatings on mild steel and on mild steel with PANI film were obtained by cathodic electrode position at constant voltage and stirring conditions. The resin concentration in the electrode position bath was 10 wt.% solid dispersion in water at pH 5.7. The applied voltage was 250 V, the temperature 26°C and the deposition time 3 min. It was shown that thin PANI film could be used to modify the surface of mild steel prior to epoxy coating deposition, due to the increased corrosion protection of a duplex PANI/epoxy coating comparing to an epoxy coating on mild steel in 3% NaCl solution.

  18. MicroRNA-target binding structures mimic microRNA duplex structures in humans.

    Directory of Open Access Journals (Sweden)

    Xi Chen

    Full Text Available Traditionally, researchers match a microRNA guide strand to mRNA sequences using sequence comparisons to predict its potential target genes. However, many of the predictions can be false positives due to limitations in sequence comparison alone. In this work, we consider the association of two related RNA structures that share a common guide strand: the microRNA duplex and the microRNA-target binding structure. We have analyzed thousands of such structure pairs and found many of them share high structural similarity. Therefore, we conclude that when predicting microRNA target genes, considering just the microRNA guide strand matches to gene sequences may not be sufficient--the microRNA duplex structure formed by the guide strand and its companion passenger strand must also be considered. We have developed software to translate RNA binding structure into encoded representations, and we have also created novel automatic comparison methods utilizing such encoded representations to determine RNA structure similarity. Our software and methods can be utilized in the other RNA secondary structure comparisons as well.

  19. Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA

    Science.gov (United States)

    Yang, Zhiyu; Price, Nathan E.; Johnson, Kevin M.

    2017-01-01

    Abstract Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3’ddR5p) at the 3’-terminus of the strand break. Interestingly, this strand scission process leaves an electrophilic α,β-unsaturated aldehyde residue embedded within the resulting nicked duplex. Here we present evidence that 3’ddR5p derivatives generated by spermine-catalyzed strand cleavage at Ap sites in duplex DNA can react with adenine residues on the opposing strand to generate a complex lesion consisting of an interstrand cross-link adjacent to a strand break. The cross-link blocks DNA replication by ϕ29 DNA polymerase, a highly processive polymerase enzyme that couples synthesis with strand displacement. This suggests that 3’ddR5p-derived cross-links have the potential to block critical cellular DNA transactions that require strand separation. LC-MS/MS methods developed herein provide powerful tools for studying the occurrence and properties of these cross-links in biochemical and biological systems. PMID:28531327

  20. A Semiempirical Model for Sigma-Phase Precipitation in Duplex and Superduplex Stainless Steels

    Science.gov (United States)

    Ferro, P.; Bonollo, F.

    2012-04-01

    Sigma phase is known to reduce the mechanical properties and corrosion resistance of duplex and superduplex stainless steels. Therefore, heat treatments and welding must be carefully performed so as to avoid the appearance of such a detrimental phase, and clearly, models suitable to faithfully predict σ-phase precipitation are very useful tools. Most fully analytical models are based on thermodynamic calculations whose agreement with experimental results is not always good, so that such models should be used for qualitative purposes only. Alternatively, it is possible to exploit semiempirical models, where time-temperature-transformation (TTT) diagrams are empirically determined for a given alloy and the continuous-cooling-transformation (CCT) diagram is calculated from the TTT diagram. In this work, a semiempirical model for σ-phase precipitation in duplex and superduplex stainless steels, under both isothermal and unisothermal conditions, is proposed. Model parameters are calculated from empirical data and CCT diagrams are obtained by means of the additivity rule, whereas experimental measurements for model validation are taken from the literature. This model gives a satisfactory estimation of σ-phase precipitates during both isothermal aging and the continuous cooling process.

  1. Cost-effectiveness of identifying aortoiliac and femoropopliteal arterial disease with angiography or duplex scanning

    International Nuclear Information System (INIS)

    Coffi, S.B.; Ubbink, D.Th.; Dijkgraaf, M.G.W.; Reekers, J.A.; Legemate, D.A.

    2008-01-01

    Objectives: Cost-effectiveness analysis of three diagnostic imaging strategies for the assessment of aortoiliac and femoropopliteal arteries in patients with peripheral arterial occlusive disease. The strategies were: angiography as the reference strategy, duplex scanning (DS) plus supplementary angiography (S1) and DS plus confirmative angiography (S2). Design, materials and methods: A decision model was built with sensitivity and specificity data from literature, supplemented with prospective hospital cost data in Euro ( Euro ). The probability of correctly identifying the status of a lesion was taken as the primary outcome. We compared strategies by assessing the extra costs per additional correctly identified case. Results: Assuming no false positive or false negative results, angiography is the most effective strategy if the prevalence of significant obstructive lesions in the aortoiliac and femoropopliteal tract exceeds 70%, or if the sensitivity of duplex scanning is lower than 83%. In case of lower prevalence, strategy S1 becomes equally or even more effective than angiography. At a prevalence of 75%, performing angiography costs Euro 8443 per extra correctly identified case compared with strategy S1. Conclusions: In most situations angiography is more effective than diagnostic strategy S1. However, if society is unwilling to pay more than Euro 8443 for knowing a patient's disease status, diagnostic strategy S1 is a cost-effective alternative to angiography, especially at lower prevalence values

  2. 6-Thioguanine alters the structure and stability of duplex DNA and inhibits quadruplex DNA formation.

    Science.gov (United States)

    Marathias, V M; Sawicki, M J; Bolton, P H

    1999-07-15

    The ability to chemically synthesize biomolecules has opened up the opportunity to observe changes in structure and activity that occur upon single atom substitution. In favorable cases this can provide information about the roles of individual atoms. The substitution of 6-thioguanine (6SG) for guanine is a potentially very useful single atom substitution as 6SG has optical, photocrosslinking, metal ion binding and other properties of potential utility. In addition, 6-mercaptopurine is a clinically important pro-drug that is activated by conversion into 6SG by cells. The results presented here indicate that the presence of 6SG blocks the formation of quadruplex DNA. The presence of 6SG alters the structure and lowers the thermal stability of duplex DNA, but duplex DNA can be formed in the presence of 6SG. These results indicate that some of the cytotoxic activity of 6SG may be due to disruption of the quadruplex structures formed by telomere and other DNAs. This additional mode of action is consistent with the delayed onset of cytotoxicity.

  3. Low temperature tensile properties and stress corrosion cracking resistance in the super duplex stainless steels weldments

    International Nuclear Information System (INIS)

    Lee, Jeung Woo; Sung, Jang Hyun; Lee, Sung Keun

    1998-01-01

    Low temperature tensile properties and SCC resistances of super duplex stainless steels and their weldments are investigated. Tensile strengths increase remarkably with decreasing test temperature, while elongations decrease steeply at -196 .deg. C after showing peak or constant value down to -100 .deg. C. Owing to the low tensile deformation of weld region, elongations of welded specimen decrease in comparison to those of unwelded specimen. The welded tensile specimen is fractured through weld region at -196 .deg. C due to the fact that the finely dispersed ferrite phase in the austenite matrix increases an opportunity to supply the crack propagation path through the brittle ferrite phase at low temperature. The stress corrosion cracking initiates preferentially at the surface ferrite phase of base metal region and propagates through ferrite phase. When the corrosion crack meets with the fibrously aligned austenite phase to the tensile direction, the ferrite phase around austenite continues to corrode. Eventually, fracture of the austenite phase begins without enduring the tensile load. The addition of Cu+W to the super duplex stainless steel deteriorates the SCC resistance in boiling MgCl 2 solution, possibly due to the increment of pits in the ferrite phase and reduction of N content in the austenite phase

  4. Effect of Plastic Deformation on the Corrosion Behavior of a Super-Duplex Stainless Steel

    Science.gov (United States)

    Renton, Neill C.; Elhoud, Abdu M.; Deans, William F.

    2011-04-01

    The role of plastic deformation on the corrosion behavior of a 25Cr-7Ni super-duplex stainless steel (SDSS) in a 3.5 wt.% sodium chloride solution at 90 °C was investigated. Different levels of plastic strain between 4 and 16% were applied to solution annealed tensile specimens and the effect on the pitting potential measured using potentiodynamic electrochemical techniques. A nonlinear relationship between the pitting potential and the plastic strain was recorded, with 8 and 16% causing a significant reduction in average E p, but 4 and 12% causing no significant change when compared with the solution-annealed specimens. The corrosion morphology revealed galvanic interaction between the anodic ferrite and the cathodic austenite causing preferential dissolution of the ferrite. Mixed potential theory and the changing surface areas of the two phases caused by the plastic deformation structures explain the reductions in pitting potential at certain critical plastic strain levels. End-users and manufacturers should evaluate the corrosion behavior of specific cold-worked duplex and SDSSs using their as-produced surface finishes assessing in-service corrosion performance.

  5. Precipitation of Chromium Nitrides in the Super Duplex Stainless Steel 2507

    Science.gov (United States)

    Pettersson, Niklas; Pettersson, Rachel F. A.; Wessman, Sten

    2015-03-01

    Precipitation of chromium nitrides during cooling from temperatures in the range 1373 K to 1523 K (1100 °C to 1250 °C) has been studied for the super duplex stainless steel 2507 (UNS S32750). Characterization with optical, scanning and transmission electron microscopy was combined to quantify the precipitation process. Primarily Cr2N nitrides were found to precipitate with a high density in the interior of ferrite grains. An increased cooling rate and/or an increased austenite spacing clearly promoted nitride formation, resulting in precipitation within a higher fraction of the ferrite grains, and lager nitride particles. Furthermore, formation of the meta-stable CrN was induced by higher cooling rates. The toughness seemed unaffected by nitrides. A slight decrease in pitting resistance was, however, noticed for quenched samples with large amounts of precipitates. The limited adverse effect on pitting resistance is attributed to the small size (~200 nm) of most nitrides. Slower cooling of duplex stainless steels to allow nitrogen partitioning is suggested in order to avoid large nitrides, and thereby produce a size distribution with a smaller detrimental effect on pitting resistance.

  6. Microstructural characteristics and corrosion behavior of a super duplex stainless steel casting

    International Nuclear Information System (INIS)

    Martins, Marcelo; Casteletti, Luiz Carlos

    2009-01-01

    The machining of super duplex stainless steel castings is usually complicated by the difficulty involved in maintaining the dimensional tolerances required for given applications. Internal stresses originating from the solidification process and from subsequent heat treatments reach levels that exceed the material's yield strength, promoting plastic strain. Stress relief heat treatments at 520 deg. C for 2 h are an interesting option to solve this problem, but because these materials present a thermodynamically metastable condition, a few precautions should be taken. The main objective of this work was to demonstrate that, after solution annealing at 1130 deg. C and water quenching, stress relief at 520 deg. C for 2 h did not alter the duplex microstructure or impair the pitting corrosion resistance of ASTM A890/A890M Grade 6A steel. This finding was confirmed by microstructural characterization techniques, including light optical and scanning electron microscopy, and X-ray diffraction. Corrosion potential measurements in synthetic sea water containing 20,000 ppm of chloride ions were also conducted at three temperatures: 5 deg. C, 25 deg. C and 60 deg. C

  7. Dry Sliding Wear Behavior of Super Duplex Stainless Steel AISI 2507: a Statistical Approach

    Directory of Open Access Journals (Sweden)

    Davanageri M.

    2016-12-01

    Full Text Available The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test. Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further, the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was obtained for the determined optimal condition by desirability function approach.

  8. Tem study of thermal ageing of ferrite in cast duplex stainless steel

    International Nuclear Information System (INIS)

    Nenonen, P.; Massoud, J.P.; Timofeev, B.T.

    2002-01-01

    The changes in the microstructure and composition of ferrite in two types of cast duplex stainless steels and in an austenitic-ferritic weld metal after long term thermal ageing has been studied using analytical transmission electron microscope (FEGTEM). A cast test steel containing Mo was investigated first as a reference material in three different conditions: as solution annealed, aged at 300 C and aged at 400 C. This investigation was carried out to gain experience of how EDS (X-ray analyser) analyser and TEM (transmission electron microscope) can be used to study elemental inhomogeneity, which is usually investigated with an atom probe (APFIM). The two other materials, an austenitic-ferritic weld metal and a cast duplex Ti-stabilised stainless steel used for long time at NPP operation temperature were investigated using the experience obtained with the test steel. The results showed that analytical TEM can be used to investigate elemental inhomogeneity of ferrite, but there are several important things to be taken into account when the spectra for this purpose are collected. These things are, such as the thickness of the specimen, probe size, contamination rate, 'elemental background' of the spectrum and possible enrichment of certain alloying elements in the surface oxide layer of the TEM-specimens. If minor elements are also analysed, it may increase the scattering of the results. (authors)

  9. AUTENTIKASI DAGING AYAM SEGAR DARI KONTAMINASI DAGING BABI MENGGUNAKAN GEN CYT-B DENGAN ANALISIS DUPLEX- POLYMERASE CHAIN REACTION

    Directory of Open Access Journals (Sweden)

    Bayu Setya Hertanto

    2017-05-01

    Full Text Available Halal is one of important aspects in consumer protection. Meat and processed meat products are food that should be controlled strictly because those are prone to be adulterated by pork contamination. Therefore, it is necessary to provide detection technique which is accurate, fast and cheap. The objective of this research was to identify the presence of impurities of pork meat on raw chicken meat using gene Cyt-b with duplex-PCR analysis. This research used six samples of raw chicken meat and raw pork. Raw chicken meat was bought from supermarkets in the city of Surakarta and raw pork was obtained from pig slaughterhouse. The percentage of raw pork contamination on raw chicken meat was designed as much as 1, 5, 10, and 25%, respectively. The DNA genome was isolated according to DNA isolation protocol from Genomic DNA Mini Kit. In addition, duplex-PCR was performed based on protocol of KAPA2G Fast Multiplex PCR kit. The data was descriptively analyzed by directly looking the DNA bands on the gel documentation apparatus. The result showed that specific DNA bands for chicken and pig were completely appeared on 1.5% of agarose gels. Duplex-PCR detect contamination of pork on raw meat of chicken at all contamination levels. This research proved that the duplex-PCR detect the contamination of pork until the level of 1%.

  10. Crystal structure of metallo DNA duplex containing consecutive Watson-Crick-like T-Hg(II)-T base pairs.

    Science.gov (United States)

    Kondo, Jiro; Yamada, Tom; Hirose, Chika; Okamoto, Itaru; Tanaka, Yoshiyuki; Ono, Akira

    2014-02-24

    The metallo DNA duplex containing mercury-mediated T-T base pairs is an attractive biomacromolecular nanomaterial which can be applied to nanodevices such as ion sensors. Reported herein is the first crystal structure of a B-form DNA duplex containing two consecutive T-Hg(II)-T base pairs. The Hg(II) ion occupies the center between two T residues. The N3-Hg(II) bond distance is 2.0 Å. The relatively short Hg(II)-Hg(II) distance (3.3 Å) observed in consecutive T-Hg(II)-T base pairs suggests that the metallophilic attraction could exist between them and may stabilize the B-form double helix. To support this, the DNA duplex is largely distorted and adopts an unusual nonhelical conformation in the absence of Hg(II). The structure of the metallo DNA duplex itself and the Hg(II)-induced structural switching from the nonhelical form to the B-form provide the basis for structure-based design of metal-conjugated nucleic acid nanomaterials. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Role of routine pre-operative screening venous duplex ultrasound in morbidly obese patients undergoing bariatric surgery

    Directory of Open Access Journals (Sweden)

    P Praveen Raj

    2017-01-01

    Full Text Available Background/Aims: It is well established that obesity is a strongly associated risk factor for post-operative deep vein thrombosis (DVT. Physical effects and pro-thrombotic, pro-inflammatory and hypofibrinolytic effects of severe obesity may predispose to idiopathic DVT (pre-operatively because of which bariatric patients are routinely screened before surgery. The aim of this study was to audit the use of routine screening venous duplex ultrasound in morbidly obese patients before undergoing bariatric surgery. Methods: We retrospectively reviewed 180 patients who underwent bariatric surgery from August 2013 to August 2014 who had undergone pre-operative screening bilateral lower-extremity venous duplex ultrasound for DVT. Data were collected on patient's demographics, history of venous thromboembolism, prior surgeries and duplex ultrasound details of the status of the deep veins and superficial veins of the lower limbs. Results: No patients had symptoms or signs of DVT pre-operatively. No patient gave history of DVT. No patient was found to have iliac, femoral or popliteal vein thrombosis. Superficial venous disease was found in 17 (8%. One patient had a right lower limb venous ulcer. Conclusion: Thromboembolic problems in the morbidly obese before bariatric surgery are infrequent, and screening venous duplex ultrasound can be done in high-risk patients only.

  12. Collateral configuration of the circle of Willis: transcranial color-coded duplex ultrasonography and comparison with postmortem anatomy

    NARCIS (Netherlands)

    Hoksbergen, A. W.; Fülesdi, B.; Legemate, D. A.; Csiba, L.

    2000-01-01

    BACKGROUND AND PURPOSE: The anterior communicating artery (AcoA) and posterior communicating arteries (PcoA) of the circle of Willis provide the main route for collateral blood flow in cases of carotid artery obstruction. Transcranial color-coded duplex ultrasonography (TCCD) allows real-time

  13. Collateral variations in circle of willis in atherosclerotic population assessed by means of transcranial color-coded duplex ultrasonography

    NARCIS (Netherlands)

    Hoksbergen, A. W.; Legemate, D. A.; Ubbink, D. T.; Jacobs, M. J.

    2000-01-01

    BACKGROUND AND PURPOSE: Transcranial color-coded duplex ultrasonography combined with common carotid artery (CCA) compression can be used to assess the collateral function of the circle of Willis. The aim of this study was to assess the unknown fraction of hemodynamic functional anterior and

  14. Effect of local information within network layers on the evolution of cooperation in duplex public goods games

    International Nuclear Information System (INIS)

    Zhou, Yifeng; Zheng, Xiaoming; Wu, Weiwei

    2015-01-01

    Traditional works of public goods game (PGG) are often studied in simplex networks where agents play games through the same type of social interactions. In order to promote cooperation against the defection in PGGs in simplex network environment, many mechanisms have been proposed from different perspectives, such as the volunteering mechanisms, and the punishment and reward approaches. However, due to diverse types of interactions between agents in reality, the study of PGG should also consider the characteristic of multiplexity of networks. Hence, we firstly model the public goods game in the duplex network (for simplification of analysis, the duplex network is considered), in which agents have two types of social interactions, and thus the network is modeled as two network layers. This type of PGG is naturally named as duplex public goods game (D-PGG), in which agents can select one of the network layers to allocate their limited resources. Then for the new game environment (D-PGG), we propose a novel perspective to promote cooperation: degrading the information integrity, i.e., agents get information just from one network layer (local information) rather than from the whole duplex network (global information) in the evolution process. Finally, through theoretical analyses and simulations, we find that if agents imitate based on the local information of the payoff in the evolution, cooperation can be generally promoted; and the extent of promotion depends on both the network structure and the similarity of the network layers

  15. Combined Triplex/Duplex Invasion of Double-Stranded DNA by "Tail-Clamp" Peptide Nucleic Acid

    DEFF Research Database (Denmark)

    Bentin, Thomas; Larsen, H. J.; Nielsen, Peter E.

    2003-01-01

    as determined by T-m measurements. Binding to double-stranded (ds) DNA occurred by combined triplex and duplex invasion as analyzed by permanganate probing. Furthermore, C-50 measurements revealed that tail-clamp PNAs consistently bound the dsDNA target more efficiently, and kinetics experiments revealed...

  16. Wear resistance of WCp/Duplex Stainless Steel metal matrix composite layers prepared by laser melt injection

    NARCIS (Netherlands)

    Do Nascimento, A. M.; Ocelik, V.; Ierardi, M. C. F.; De Hosson, J. Th. M.

    2008-01-01

    Laser Melt Injection (LMI) was used to prepare metal matrix composite layers with a thickness of about 0.7 mm and approximately 10% volume fraction of WC particles in three kinds of Cast Duplex Stainless Steels (CDSSs). WC particles were injected into the molten surface layer using Nd:YAG high power

  17. Microstructure of reaction zone in WCp/duplex stainless steels matrix composites processing by laser melt injection

    NARCIS (Netherlands)

    Do Nascimento, A. M.; Ocelik, V.; Ierardi, M. C. F.; De Hosson, J. Th. M.

    2008-01-01

    The laser melt injection (LMI) process has been used to create a metal matrix composite consisting of 80gm sized multi-grain WC particles embedded in three cast duplex stainless steels. The microstruture was investigated by scanning electron microscopy with integrated EDS and electron back-scatter

  18. Dual door entry to exciplex emission in a chimeric DNA duplex containing non-nucleoside-nucleoside pair.

    Science.gov (United States)

    Bag, Subhendu Sekhar; Talukdar, Sangita; Kundu, Rajen; Saito, Isao; Jana, Subhashis

    2014-01-25

    Dual door entry to exciplex formation was established in a chimeric DNA duplex wherein a fluorescent non-nucleosidic base surrogate () is paired against a fluorescent nucleosidic base surrogate (). Packing of the nucleobases via intercalative stacking interactions led to an exciplex emission either via FRET from the donor or direct excitation of the FRET acceptor .

  19. The usefulness of Duplex Doppler ultrasound in the angiological and dermatological diagnosis of patients with blue toe syndrome.

    Science.gov (United States)

    Pawlaczyk, Katarzyna; Gabriel, Marcin; Strzelecka-Węklar, Daria A; Krasiński, Zbigniew; Stanisic, Michal; Gabriel, Zofia; Dzieciuchowicz, Łukasz; Adamski, Zygmunt

    2017-10-01

    Peripheral microembolism is one of the most frequent causes of acute limb ischemia. In order to effectively prevent relapses it is essential to localize and eliminate the source of embolism. To evaluate the role of Duplex Doppler ultrasound examination in identifying the causes of blue toe syndrome (BTS). The group of 165 patients with clinical symptoms of BTS on their upper limbs ( n = 16) and lower limbs ( n = 149) was investigated. They all underwent Duplex Doppler ultrasound of the major arteries of the extremities, where ischemic changes occurred. Morphological and functional changes which might be potential sources of microembolism were identified in 146 patients. These changes included significant short-length stenoses or unstable atherosclerotic plaque ( n = 73), true aneurysms ( n = 42) and pseudoaneurysms ( n = 17). In 11 cases, pathology of vascular prostheses in the form of anastomotic aneurysms, infection and residual thrombi after fibrinolysis was detected. In all cases, Duplex diagnosis was confirmed by other imaging and intraoperative tests. Duplex Doppler ultrasound of the arteries in the affected limb with a full length view should be the first-line examination in diagnosing patients with BTS. In the absence of hemodynamic blood flow disturbances in the major arteries in patients with symptoms of BTS, it is advisable to start haematological tests to identify/exclude congenital or acquired thrombophilia.

  20. Value of duplex scanning compared with angiography and pressure measurement in the assessment of aortoiliac arterial lesions

    NARCIS (Netherlands)

    Legemate, D. A.; Teeuwen, C.; Hoeneveld, H.; Eikelboom, B. C.

    1991-01-01

    To detect haemodynamically significant lesions in the aortoiliac arteries, invasive tests such as angiography and intra-arterial pressure measurement (IAPM) are considered valuable diagnostic tools. The value of duplex scanning as a direct non-invasive examination technique was prospectively