Survey of methods used to asses human reliability in the human factors reliability benchmark exercise

International Nuclear Information System (INIS)

Poucet, A.

1988-01-01

The Joint Research Centre of the European Commission has organised a Human Factors Reliability Benchmark Exercise (HF-RBE) with the aim to assess the state-of-the-art in human reliability modelling and assessment. Fifteen teams from eleven countries, representing industry, utilities, licensing organisations and research institutes, participate in the HF-RBE, which is organised around two study cases: (1) analysis of routine functional test and maintenance procedures, with the aim to assess the probability of test-induced failures, the probability of failures to remain unrevealed, and the potential to initiate transients because of errors performed in the test; and (2) analysis of human actions during an operational transient, with the aim to assess the probability that the operators will correctly diagnose the malfunctions and take proper corrective action. The paper briefly reports how the HF-RBE was structured and gives an overview of the methods that have been used for predicting human reliability in both study cases. The experience in applying these methods is discussed and the results obtained are compared. (author)

Considering the human factors contribution to the risk in the design choices

International Nuclear Information System (INIS)

Papin, B.

2004-01-01

Abstract: With the increasing reliability of the modern technological systems, the human contribution to the global risk in the operation of industrial systems is becoming more and more significant: in the nuclear reactor operation for example, a recent PSA estimation of this contribution is about 25% of the risk of core melting, all situations considered. This urges the designers of future plants to consider the minimization of this Human Factor (HF) contribution, at the very early stage of their design: the experience feedback shows that this is indeed at this stage that the fundamental design options, impacting the most the human reliability in operation, are fixed. The problem is that at these early design stages, it is also quite impossible to apply formal human reliability methods to support this HF optimisation, while the precise operating conditions of the plant are not yet known in enough details. In this paper, another approach of the HF evaluation during the design, based on the functional and operational complexity assessment, is proposed. As an illustration, this approach is used to compare various concepts of nuclear reactors from the point of view of the Human Factor relevance. (authors)

Undergraduates Learn about Industrial-Organizational Psychology and Human Factors from an Informational Brochure

Science.gov (United States)

Kottke, Janet L.; Shoenfelt, Elizabeth L.; Stone, Nancy J.

2017-01-01

An informational brochure was created to assist students and faculty unfamiliar with the industrial-organizational (IO) and human factors (HF) disciplines. The brochure highlights the content of these two professions, presents advice for undergraduates to prepare for admission to IO and HF graduate programs, provides sources of IO and HF…

Development and test of a classification scheme for human factors in incident reports

International Nuclear Information System (INIS)

Miller, R.; Freitag, M.; Wilpert, B.

1997-01-01

The Research Center System Safety of the Berlin University of Technology conducted a research project on the analysis of Human Factors (HF) aspects in incident reported by German Nuclear Power Plants. Based on psychological theories and empirical studies a classification scheme was developed which permits the identification of human involvement in incidents. The classification scheme was applied in an epidemiological study to a selection of more than 600 HF - relevant incidents. The results allow insights into HF related problem areas. An additional study proved that the application of the classification scheme produces results which are reliable and independent from raters. (author). 13 refs, 1 fig

The human factors approach at EDF

International Nuclear Information System (INIS)

Colas, A.

2004-01-01

At the dawn of the 21st century, French electricity utility EDF is facing a number of major changes, in particular the liberalisation of European energy markets and the restructuring needed to cope with this development. EDF's approach to human factors (HF) aspects is also undergoing major changes, since people obviously play a predominant role in any organisational structure. (author)

Local panels and maintainability human factors assessment for AP1000 nuclear power plant

International Nuclear Information System (INIS)

Li, Zhonghai; Reed, Julie I.

2011-01-01

A document entitled 'AP1000 Local Panels and Maintainability Human Factors Design Guidelines' was produced to aid the designers to specifically include human factors (HF) considerations in the design, operation, and maintenance of local control stations and plant equipment. To ensure that the applicable HF design guidelines are appropriately applied to the design of local panels and maintenance activities, and identify any HF improvement opportunities that can readily be implemented at the design stage, a HF assessment of maintenance activities and local plant operations is underway. This assessment gives priority to local control stations and equipment which have been identified as having a potential impact on safety. This includes risk-significant systems, structures and components (SSCs) identified through the probabilistic risk assessment (PRA), and local operator actions as required by the Emergency Operating Procedures (EOPs). Local actions, maintenance activities and associated operator interfaces are reviewed against the relevant HF guidelines. The results of the assessment include a description of the component, associated local actions and/or required maintenance activities, good design features and/or potential issues, and recommendations for change or improvement. These results are communicated to responsible design engineers who evaluate the impact to plant design and implement design changes, if deemed necessary. (author)

Deep Coverage Proteomics Identifies More Low-Abundance Missing Proteins in Human Testis Tissue with Q-Exactive HF Mass Spectrometer.

Science.gov (United States)

Wei, Wei; Luo, Weijia; Wu, Feilin; Peng, Xuehui; Zhang, Yao; Zhang, Manli; Zhao, Yan; Su, Na; Qi, YingZi; Chen, Lingsheng; Zhang, Yangjun; Wen, Bo; He, Fuchu; Xu, Ping

2016-11-04

Since 2012, missing proteins (MPs) investigation has been one of the critical missions of Chromosome-Centric Human Proteome Project (C-HPP) through various biochemical strategies. On the basis of our previous testis MPs study, faster scanning and higher resolution mass-spectrometry-based proteomics might be conducive to MPs exploration, especially for low-abundance proteins. In this study, Q-Exactive HF (HF) was used to survey proteins from the same testis tissues separated by two separating methods (tricine- and glycine-SDS-PAGE), as previously described. A total of 8526 proteins were identified, of which more low-abundance proteins were uniquely detected in HF data but not in our previous LTQ Orbitrap Velos (Velos) reanalysis data. Further transcriptomics analysis showed that these uniquely identified proteins by HF also had lower expression at the mRNA level. Of the 81 total identified MPs, 74 and 39 proteins were listed as MPs in HF and Velos data sets, respectively. Among the above MPs, 47 proteins (43 neXtProt PE2 and 4 PE3) were ranked as confirmed MPs after verifying with the stringent spectra match and isobaric and single amino acid variants filtering. Functional investigation of these 47 MPs revealed that 11 MPs were testis-specific proteins and 7 MPs were involved in spermatogenesis process. Therefore, we concluded that higher scanning speed and resolution of HF might be factors for improving the low-abundance MP identification in future C-HPP studies. All mass-spectrometry data from this study have been deposited in the ProteomeXchange with identifier PXD004092.

A Virtual Campus Based on Human Factor Engineering

Science.gov (United States)

Yang, Yuting; Kang, Houliang

2014-01-01

Three Dimensional or 3D virtual reality has become increasingly popular in many areas, especially in building a digital campus. This paper introduces a virtual campus, which is based on a 3D model of The Tourism and Culture College of Yunnan University (TCYU). Production of the virtual campus was aided by Human Factor and Ergonomics (HF&E), an…

An ergonomics action research demonstration: integrating human factors into assembly design processes.

Science.gov (United States)

Village, J; Greig, M; Salustri, F; Zolfaghari, S; Neumann, W P

2014-01-01

In action research (AR), the researcher participates 'in' the actions in an organisation, while simultaneously reflecting 'on' the actions to promote learning for both the organisation and the researchers. This paper demonstrates a longitudinal AR collaboration with an electronics manufacturing firm where the goal was to improve the organisation's ability to integrate human factors (HF) proactively into their design processes. During the three-year collaboration, all meetings, workshops, interviews and reflections were digitally recorded and qualitatively analysed to inform new 'actions'. By the end of the collaboration, HF tools with targets and sign-off by the HF specialist were integrated into several stages of the design process, and engineers were held accountable for meeting the HF targets. We conclude that the AR approach combined with targeting multiple initiatives at different stages of the design process helped the organisation find ways to integrate HF into their processes in a sustainable way. Researchers acted as a catalyst to help integrate HF into the engineering design process in a sustainable way. This paper demonstrates how an AR approach can help achieve HF integration, the benefits of using a reflective stance and one method for reporting an AR study.

Principle of an operational complexity index for the characterization of the human factor relevance of future reactors concepts

International Nuclear Information System (INIS)

Papin, Bernard

2004-01-01

With the increasing reliability of the modern technological systems, the human contribution to the global risk in the operation of industrial systems is becoming more and more significant : in the nuclear reactor operation for example, a recent PSA estimation of this contribution is about 25% of the risk of core melting, all situations considered. This urges the designers of future nuclear reactors to consider the minimisation of this Human Factor (HF) contribution, at the very early stage of their design : the experience feedback shows that this is indeed at this stage that the fundamental design options, impacting the most the human reliability in operation, are fixed. The problem is that at these early design stages, it is also quite impossible to apply formal human reliability methods to support this HF optimisation, while the precise operating conditions of the reactor are not yet known in enough details. In this paper, another approach of the HF evaluation during the design, based on the functional and operational complexity assessment, is proposed. As an illustration, this approach is used to compare various concepts of Pressurized Water Reactors from the point of view of the Human Factor relevance. (Author)

Human factors paradigm and customer care perceptions.

Science.gov (United States)

Clarke, Colin; Eales-Reynolds, Lesley-Jane

2015-01-01

The purpose of this paper is to examine if customer care (CC) can be directly linked to patient safety through a human factors (HF) framework. Data from an online questionnaire, completed by a convenience healthcare worker sample (n=373), was interrogated using thematic analysis within Vincent et al.'s (1998) HF theoretical framework. This proposes seven areas affecting patient safety: institutional context, organisation and management, work environment, team factors, individual, task and patient. Analysis identified responses addressing all framework areas. Responses (597) principally focused on work environment 40.7 per cent (n=243), organisation and management 28.8 per cent (n=172). Nevertheless, reference to other framework areas were clearly visible within the data: teams 10.2 per cent (n=61), individual 6.7 per cent (n=40), patients 6.0 per cent (n=36), tasks 4.2 per cent (n=24) and institution 3.5 per cent (n=21). Findings demonstrate congruence between CC perceptions and patient safety within a HF framework. The questionnaire requested participants to identify barriers to rather than CC enablers. Although this was at a single site complex organisation, it was similar to those throughout the NHS and other international health systems. CC can be viewed as consonant with patient safety rather than the potentially dangerous consumerisation stance, which could ultimately compromise patient safety. This work provides an original perspective on the link between CC and patient safety and has the potential to re-focus healthcare perceptions.

Transforming the culture of surgical education: promoting teacher identity through human factors training.

Science.gov (United States)

Cahan, Mitchell A; Starr, Susan; Larkin, Anne C; Litwin, Demetrius E M; Sullivan, Kate M; Quirk, Mark E

2011-07-01

Promoting a culture of teaching may encourage students to choose a surgical career. Teaching in a human factors (HF) curriculum, the nontechnical skills of surgery, is associated with surgeons' stronger identity as teachers and with clinical students' improved perception of surgery and satisfaction with the clerkship experience. To describe the effects of an HF curriculum on teaching culture in surgery. Surgeons and educators developed an HF curriculum including communication, teamwork, and work-life balance. Teacher identity, student interest in a surgical career, student perception of the HF curriculum, and teaching awards. Ninety-two of 123 faculty and residents in a single program (75% of total) completed a survey on teacher identity. Fifteen of the participants were teachers of HF. Teachers of HF scored higher than control participants on the total score for teacher identity (P < .001) and for subcategories of global teacher identity (P = .001), intrinsic satisfaction (P = .001), skills and knowledge (P = .006), belonging to a group of teachers (P < .001), feeling a responsibility to teach (P = .008), receiving rewards (P =.01), and HF (P = .02). Third-year clerks indicated that they were more likely to select surgery as their career after the clerkship and rated the curriculum higher when it was taught by surgeons than when taught by educators. Of the teaching awards presented to surgeons during HF years, 100% of those awarded to attending physicians and 80% of those awarded to residents went to teachers of HF. Curricular focus on HF can strengthen teacher identity, improve teacher evaluations, and promote surgery as a career choice.

Human hair follicle pluripotent stem (hfPS) cells promote regeneration of peripheral-nerve injury: an advantageous alternative to ES and iPS cells.

Science.gov (United States)

Amoh, Yasuyuki; Kanoh, Maho; Niiyama, Shiro; Hamada, Yuko; Kawahara, Katsumasa; Sato, Yuichi; Hoffman, Robert M; Katsuoka, Kensei

2009-08-01

The optimal source of stem cells for regenerative medicine is a major question. Embryonic stem (ES) cells have shown promise for pluripotency but have ethical issues and potential to form teratomas. Pluripotent stem cells have been produced from skin cells by either viral-, plasmid- or transposon-mediated gene transfer. These stem cells have been termed induced pluripotent stem cells or iPS cells. iPS cells may also have malignant potential and are inefficiently produced. Embryonic stem cells may not be suited for individualized therapy, since they can undergo immunologic rejection. To address these fundamental problems, our group is developing hair follicle pluripotent stem (hfPS) cells. Our previous studies have shown that mouse hfPS cells can differentiate to neurons, glial cells in vitro, and other cell types, and can promote nerve and spinal cord regeneration in vivo. hfPS cells are located above the hair follicle bulge in what we have termed the hfPS cell area (hfPSA) and are nestin positive and keratin 15 (K-15) negative. Human hfPS cells can also differentiate into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. In the present study, human hfPS cells were transplanted in the severed sciatic nerve of the mouse where they differentiated into glial fibrillary-acidic-protein (GFAP)-positive Schwann cells and promoted the recovery of pre-existing axons, leading to nerve generation. The regenerated nerve recovered function and, upon electrical stimulation, contracted the gastrocnemius muscle. The hfPS cells can be readily isolated from the human scalp, thereby providing an accessible, autologous and safe source of stem cells for regenerative medicine that have important advantages over ES or iPS cells. (c) 2009 Wiley-Liss, Inc.

What do human factors and ergonomics professionals value in research publications? Re-examining the research-practice gap.

Science.gov (United States)

Chung, Amy Z Q; Williamson, Ann; Shorrock, Steven T

2014-01-01

The research-practice gap is of concern in human factors/ergonomics (HF/E) as there is a belief that HF/E research may not be making an impact on practice in the 'real world'. A potential issue is what researchers and practitioners perceive as important in HF/E journal articles as a primary means of conveying research findings to practitioners. This study examined the characteristics that make scientific journal articles appeal to HF/E researchers and practitioners using a web-based survey. HF/E researchers and practitioners were more similar than expected in judgements of important attributes and the selection of articles. Both practitioners and researchers considered practical significance to be more important than theoretical significance, in direct contrast to professionals from a related discipline--psychology. Well-written articles were appreciated across disciplines. The results signal a strong interest in practical applications in HF/E, but a relative lack of focus on development of theories that should be the basis for practical applications.

Structural and functional organization of the HF.10 human zinc finger gene (ZNF35) located on chromosome 3p21-p22

DEFF Research Database (Denmark)

Lanfrancone, L; Pengue, G; Pandolfi, P P

1992-01-01

We report the structural and functional characterization of the HF.10 zinc finger gene (ZNF35) in normal human cells, as well as a processed pseudogene. The HF.10 gene spans about 13 kb and it is interrupted by three introns. All 11 zinc finger DNA-binding domains are contiguously encoded within...... and partial nucleotide sequencing of the HF.10 pseudogene indicated that it has arisen by retroposition of spliced HF.10 mRNA. In situ hybridization experiments revealed that both the functional locus and the pseudogene map to chromosome 3p21p22, a region that is frequently deleted in small cell lung...... and renal carcinomas. Hybridization of the HF.10 gene and the HF.10 pseudogene DNA probes to metaphases from a small cell lung carcinoma cell line with the 3p deletion revealed that both loci are part of the deleted chromosome region....

Human factors measurement for future air traffic control systems.

Science.gov (United States)

Langan-Fox, Janice; Sankey, Michael J; Canty, James M

2009-10-01

This article provides a critical review of research pertaining to the measurement of human factors (HF) issues in current and future air traffic control (ATC). Growing worldwide air traffic demands call for a radical departure from current ATC systems. Future systems will have a fundamental impact on the roles and responsibilities of ATC officers (ATCOs). Valid and reliable methods of assessing HF issues associated with these changes, such as a potential increase (or decrease) in workload, are of utmost importance for advancing theory and for designing systems, procedures, and training. We outline major aviation changes and how these relate to five key HF issues in ATC. Measures are outlined, compared, and evaluated and are followed by guidelines for assessing these issues in the ATC domain. Recommendations for future research are presented. A review of the literature suggests that situational awareness and workload have been widely researched and assessed using a variety of measures, but researchers have neglected the areas of trust, stress, and boredom. We make recommendations for use of particular measures and the construction of new measures. It is predicted that, given the changing role of ATCOs and profound future airspace requirements and configurations, issues of stress, trust, and boredom will become more significant. Researchers should develop and/or refine existing measures of all five key HF issues to assess their impact on ATCO performance. Furthermore, these issues should be considered in a holistic manner. The current article provides an evaluation of research and measures used in HF research on ATC that will aid research and ATC measurement.

Application of Human Factors Methods to Design Healthcare Work Systems: Instance of the prevention of Adverse Drug Events.

Science.gov (United States)

Marcilly, Romaric; Beuscart-Zephir, Marie-Catherine

2015-01-01

Human Factors (HF) methods are increasingly needed to support the design of new technologies in order to avoid that introducing those technologies into healthcare work systems induces use errors with potentially catastrophic consequences for the patients. This chapter illustrates the application of HF methods in developing two health technologies aiming at securing the hospital medication management process. Lessons learned from this project highlight the importance of (i) analyzing the work system in which the technology is intended to be implemented, (ii) involving end users in the design process and (iii) the intermediation role of HF between end users and scientific/technical experts.

How to evaluate the effectiveness of safety assessment in the area of human factors?

International Nuclear Information System (INIS)

Rolina, G.; Moisdon, J.C.; Jeffroy, F.

2007-01-01

The Three Mile Island nuclear reactor accident in 1979 led to a new approach regarding safety that includes a better consideration of man and his activities. A few years later, with the set up of a group of specialists at Electricite de France and at the Institute for Radiological Protection and Nuclear Safety, a new player appeared at France's nuclear safety organisation: the assessment expert specialising in human factors (HF). The improvement of man-machine interfaces was one of the first projects undertaken by the HF experts, the majority of whom specialise in ergonomics. A review of the literature and analysis of the archives, revealed that the specialists' scope of investigation has since increased; so that organisation is also the subject of HF assessment. However, this area is not one of consensual or established knowledge; neither researchers nor specialists can agree on a model of safe organisation. What then can we say about effectiveness of HF assessment? How can we define the criteria of effectiveness of a safety assessment production system in this area? The question is the subject of original research based on collaboration between the scientific management centre (CGS) of the Ecole des Mines in Paris and the section for the study of human factors (SEFH) at IRSN. To address this question, the CGS team monitors some assessments to which SEFH contributes. In other words, it attends different meetings on framing, technical instruction, reporting, taking notes and collecting related documents (minutes of meetings,...). It carries out additional interviews with different parties involved in assessment in order to ascertain their point of view. A sample of five assessments was defined to cover a varied number of situations encountered by the team of HF experts. The type of facility, the operator and the subject concerned are some of the variables integrated for this choice

Ergonomics action research II: a framework for integrating HF into work system design.

Science.gov (United States)

Neumann, W P; Village, J

2012-01-01

This paper presents a conceptual framework that can support efforts to integrate human factors (HF) into the work system design process, where improved and cost-effective application of HF is possible. The framework advocates strategies of broad stakeholder participation, linking of performance and health goals, and process focussed change tools that can help practitioners engage in improvements to embed HF into a firm's work system design process. Recommended tools include business process mapping of the design process, implementing design criteria, using cognitive mapping to connect to managers' strategic goals, tactical use of training and adopting virtual HF (VHF) tools to support the integration effort. Consistent with organisational change research, the framework provides guidance but does not suggest a strict set of steps. This allows more adaptability for the practitioner who must navigate within a particular organisational context to secure support for embedding HF into the design process for improved operator wellbeing and system performance. There has been little scientific literature about how a practitioner might integrate HF into a company's work system design process. This paper proposes a framework for this effort by presenting a coherent conceptual framework, process tools, design tools and procedural advice that can be adapted for a target organisation.

Ergonomics/Human factors needs of an ageing workforce in the manufacturing sector.

Science.gov (United States)

W Stedmon, Alex; Howells, Hannah; R Wilson, John; Dianat, Iman

2012-01-01

As the effects of demographic transition are realised around the world, many in-dustrial societies are facing the effects of a baby boom generation, increased life expectancies, decreased birth rates and recent changes to retirement legislation with the result that older work¬ers are set to comprise a greater proportion of the labour force. This paper reviews the evidence for the physical and cognitive factors that characterise an ageing workforce in manufacturing. From an ergonomics and human factors (E/HF) pers¬pective, characteristics of manufacturing tasks and the effects of ageing provide an insight into how the industry will have to adapt to support the user needs of the older worker in the future. The approach taken is drawn from Ilmarinen's framework of age, experience, and work performance, from which specific E/HF issues are explored. There would appear to potential to support physical decline in older workers within manufacturing jobs through increased mechanisation and automation; however, those factors associated with cognitive human factors are less clear. Increased mechanisation and automation can place greater loads and demands on the older worker where cognitive decline is more subtle and varied between workers. Using historical and contemporary findings and the relationship between age, experience, and work performance is redrawn to include both cognitive skills and physical attributes to provide recommendations for future job design and worker needs.

Thermoelectric properties of doped BaHfO_3

International Nuclear Information System (INIS)

Dixit, Chandra Kr.; Bhamu, K. C.; Sharma, Ramesh

2016-01-01

We have studied the structural stability, electronic structure, optical properties and thermoelectric properties of doped BaHfO_3 by full potential linearized augmented plane wave (FP-LAPW) method. The electronic structure of BaHfO_3 doped with Sr shows enhances the indirect band gaps of 3.53 eV, 3.58 eV. The charge density plots show strong ionic bonding in Ba-Hf, and ionic and covalent bonding between Hf and O. Calculations of the optical spectra, viz., the dielectric function, refractive index and extinction coefficient are performed for the energy range are calculated and analyzed. Thermoelectric properties of semi conducting are also reported first time. The doped BaHfO_3 is approximately wide band gap semiconductor with the large p-type Seebeck coefficient. The power factor of BaHfO_3 is increased with Sr doping, decreases because of low electrical resistivity and thermal conductivity.

Human Factors Process Task Analysis Liquid Oxygen Pump Acceptance Test Procedure for the Advanced Technology Development Center

Science.gov (United States)

Diorio, Kimberly A.

2002-01-01

A process task analysis effort was undertaken by Dynacs Inc. commencing in June 2002 under contract from NASA YA-D6. Funding was provided through NASA's Ames Research Center (ARC), Code M/HQ, and Industrial Engineering and Safety (IES). The John F. Kennedy Space Center (KSC) Engineering Development Contract (EDC) Task Order was 5SMA768. The scope of the effort was to conduct a Human Factors Process Failure Modes and Effects Analysis (HF PFMEA) of a hazardous activity and provide recommendations to eliminate or reduce the effects of errors caused by human factors. The Liquid Oxygen (LOX) Pump Acceptance Test Procedure (ATP) was selected for this analysis. The HF PFMEA table (see appendix A) provides an analysis of six major categories evaluated for this study. These categories include Personnel Certification, Test Procedure Format, Test Procedure Safety Controls, Test Article Data, Instrumentation, and Voice Communication. For each specific requirement listed in appendix A, the following topics were addressed: Requirement, Potential Human Error, Performance-Shaping Factors, Potential Effects of the Error, Barriers and Controls, Risk Priority Numbers, and Recommended Actions. This report summarizes findings and gives recommendations as determined by the data contained in appendix A. It also includes a discussion of technology barriers and challenges to performing task analyses, as well as lessons learned. The HF PFMEA table in appendix A recommends the use of accepted and required safety criteria in order to reduce the risk of human error. The items with the highest risk priority numbers should receive the greatest amount of consideration. Implementation of the recommendations will result in a safer operation for all personnel.

Hf layer thickness dependence of resistive switching characteristics of Ti/Hf/HfO2/Au resistive random access memory device

Science.gov (United States)

Nakajima, Ryo; Azuma, Atsushi; Yoshida, Hayato; Shimizu, Tomohiro; Ito, Takeshi; Shingubara, Shoso

2018-06-01

Resistive random access memory (ReRAM) devices with a HfO2 dielectric layer have been studied extensively owing to the good reproducibility of their SET/RESET switching properties. Furthermore, it was reported that a thin Hf layer next to a HfO2 layer stabilized switching properties because of the oxygen scavenging effect. In this work, we studied the Hf thickness dependence of the resistance switching characteristics of a Ti/Hf/HfO2/Au ReRAM device. It is found that the optimum Hf thickness is approximately 10 nm to obtain good reproducibility of SET/RESET voltages with a small RESET current. However, when the Hf thickness was very small (∼2 nm), the device failed after the first RESET process owing to the very large RESET current. In the case of a very thick Hf layer (∼20 nm), RESET did not occur owing to the formation of a leaky dielectric layer. We observed the occurrence of multiple resistance states in the RESET process of the device with a Hf thickness of 10 nm by increasing the RESET voltage stepwise.

Evolution of human factors research and studies of health information technologies: the role of patient safety

NARCIS (Netherlands)

Beuscart-Zéphir, M. C.; Borycki, E.; Carayon, P.; Jaspers, M. W. M.; Pelayo, S.

2013-01-01

The objective of this survey paper is to present and explain the impact of recent regulations and patient safety initiatives (EU, US and Canada) on Human Factors (HF)/Usability studies and research focusing on Health Information Technology (HIT). The authors have selected the most prominent of these

Comparison of HfCl4, HfI4, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO2 films deposited by ALD: A DFT study

International Nuclear Information System (INIS)

Cortez-Valadez, M.; Fierro, C.; Farias-Mancilla, J.R.; Vargas-Ortiz, A.; Flores-Acosta, M.; Ramírez-Bon, R.; Enriquez-Carrejo, J.L.

2016-01-01

Highlights: • Hafnium oxide growth on Si(100) by atomic layer deposition was simulated. • The interface structure was considered as silicate and silicide. • The interface was studied employing DFT. • TDMA-Hf precursor show better interface stability. - Abstract: The final structure of HfO 2 films grown by atomic layer deposition (ALD) after reaction with OH − ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl 4 (hafnium tetrachloride), HfI 4 (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO–H was studied employing the B3LYP (Becke 3-parameter, Lee–Yang–Parr) hybrid functional and the PBE (Perdew–Burke–Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

Ergonomics/Human Factors Needs of an Ageing Workforce in the Manufacturing Sector

Directory of Open Access Journals (Sweden)

Alex W. Stedmon

2012-12-01

Full Text Available Background: As the effects of demographic transition are realised around the world, many in-dustrial societies are facing the effects of a baby boom generation, increased life expectancies, decreased birth rates and recent changes to retirement legislation with the result that older work-ers are set to comprise a greater proportion of the labour force.Methods: This paper reviews the evidence for the physical and cognitive factors that characterise an ageing workforce in manufacturing. From an ergonomics and human factors (E/HF pers-pective, characteristics of manufacturing tasks and the effects of ageing provide an insight into how the industry will have to adapt to support the user needs of the older worker in the future. The approach taken is drawn from Ilmarinen’s framework of age, experience, and work performance, from which specific E/HF issues are explored.Results: There would appear to potential to support physical decline in older workers within manufacturing jobs through increased mechanisation and automation; however, those factors associated with cognitive human factors are less clear. Increased mechanisation and automation can place greater loads and demands on the older worker where cognitive decline is more subtle and varied between workers.Conclusion: Using historical and contemporary findings and the relationship between age, experience, and work performance is redrawn to include both cognitive skills and physical attributes to provide recommendations for future job design and worker needs.

Ergonomics/Human Factors Needs of an Ageing Workforce in the Manufacturing Sector

Science.gov (United States)

W. Stedmon, Alex; Howells, Hannah; R. Wilson, John; Dianat, Iman

2012-01-01

Background: As the effects of demographic transition are realised around the world, many in-dustrial societies are facing the effects of a baby boom generation, increased life expectancies, decreased birth rates and recent changes to retirement legislation with the result that older work¬ers are set to comprise a greater proportion of the labour force. Methods: This paper reviews the evidence for the physical and cognitive factors that characterise an ageing workforce in manufacturing. From an ergonomics and human factors (E/HF) pers¬pective, characteristics of manufacturing tasks and the effects of ageing provide an insight into how the industry will have to adapt to support the user needs of the older worker in the future. The approach taken is drawn from Ilmarinen’s framework of age, experience, and work performance, from which specific E/HF issues are explored. Results: There would appear to potential to support physical decline in older workers within manufacturing jobs through increased mechanisation and automation; however, those factors associated with cognitive human factors are less clear. Increased mechanisation and automation can place greater loads and demands on the older worker where cognitive decline is more subtle and varied between workers. Conclusion: Using historical and contemporary findings and the relationship between age, experience, and work performance is redrawn to include both cognitive skills and physical attributes to provide recommendations for future job design and worker needs. PMID:24688925

Comparison of HfCl4, HfI4, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO2 films deposited by ALD: A DFT study

Science.gov (United States)

Cortez-Valadez, M.; Fierro, C.; Farias-Mancilla, J. R.; Vargas-Ortiz, A.; Flores-Acosta, M.; Ramírez-Bon, R.; Enriquez-Carrejo, J. L.; Soubervielle-Montalvo, C.; Mani-Gonzalez, P. G.

2016-06-01

The final structure of HfO2 films grown by atomic layer deposition (ALD) after reaction with OH- ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl4 (hafnium tetrachloride), HfI4 (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO-H was studied employing the B3LYP (Becke 3-parameter, Lee-Yang-Parr) hybrid functional and the PBE (Perdew-Burke-Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

Are We There Yet? Human Factors Knowledge and Health Information Technology - the Challenges of Implementation and Impact.

Science.gov (United States)

Turner, P; Kushniruk, A; Nohr, C

2017-08-01

Objective: To review the developments in human factors (HF) research on the challenges of health information technology (HIT) implementation and impact given the continuing incidence of usability problems and unintended consequences from HIT development and use. Methods: A search of PubMed/Medline and Web of Science® identified HF research published in 2015 and 2016. Electronic health records (EHRs) and patient-centred HIT emerged as significant foci of recent HF research. The authors selected prominent papers highlighting ongoing HF and usability challenges in these areas. This selective rather than systematic review of recent HF research highlights these key challenges and reflects on their implications on the future impact of HF research on HIT. Results: Research provides evidence of continued poor design, implementation, and usability of HIT, as well as technology-induced errors and unintended consequences. The paper highlights support for: (i) strengthening the evidence base on the benefits of HF approaches; (ii) improving knowledge translation in the implementation of HF approaches during HIT design, implementation, and evaluation; (iii) increasing transparency, governance, and enforcement of HF best practices at all stages of the HIT system development life cycle. Discussion and Conclusion: HF and usability approaches are yet to become embedded as integral components of HIT development, implementation, and impact assessment. As HIT becomes ever-more pervasive including with patients as end-users, there is a need to expand our conceptualisation of the problems to be addressed and the suite of tactics and strategies to be used to calibrate our pro-active involvement in its improvement. Georg Thieme Verlag KG Stuttgart.

Review of human factors R and D in the nuclear power industry

International Nuclear Information System (INIS)

Parris, H.L.

1986-01-01

The history of human factors (HF) R and D in the nuclear power industry can clearly be divided into two phases: pre- and post-Three Mile Island (TMI). Pre-TMI, most people in the industry were unfamiliar with the discipline and its contributions to military and space system designs, and the number of HF professionals involved with nuclear power could essentially be counted on the fingers of two hands. Consequently, there was little research into the improvement of plant man/machine interfaces. The picture changed dramatically in the aftermath of TMI as investigation after investigation pointed to deficiencies in the operator/control room interface, training, procedures, communications, and organizational effectiveness. This paper first outlines pre-TMI events, then examines the post-TMI scenario, and concludes with summary observations and suggestions for future efforts

Theoretical predictions of hydrolysis and complex formation of group-4 elements Zr, Hf and Rf in HF and HCl solutions

International Nuclear Information System (INIS)

Pershina, V.; Trubert, D.; Le Naour, C.; Kratz, J.V.

2002-01-01

Fully relativistic molecular density-functional calculations of the electronic structures of hydrated, hydrolyzed and fluoride/chloride complexes have been performed for group-4 elements Zr, Hf, and element 104, Rf. Using the electronic density distribution data, relative values of the free energy change for hydrolysis and complex formation reactions were defined. The results show the following trend for the first hydrolysis step of the cationic species: Zr>Hf>Rf in agreement with experiments. For the complex formation in HF solutions, the trend to a decrease from Zr to Hf is continued with Rf, provided no hydrolysis takes place. At pH>0, further fluorination of hydrolyzed species or fluoro-complexes has an inversed trend in the group Rf≥Zr>Hf, with the difference between the elements being very small. For the complex formation in HCl solutions, the trend is continued with Rf, so that Zr>Hf>Rf independently of pH. A decisive energetic factor in hydrolysis or complex formation processes proved to be a predominant electrostatic metal-ligand interaction. Trends in the K d (distribution coefficient) values for the group-4 elements are expected to follow those of the complex formation

Thermoelectric properties of doped BaHfO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Dixit, Chandra Kr., E-mail: ckparadise@gmail.com, E-mail: sharmarameshfgiet@gmail.com [Dept. of Physics, Dr. Shakuntala Misra National Rehabilitation University, Lucknow-229001, U.P India (India); Bhamu, K. C. [Department of Physics, Goa University, Goa-403 206 (India); Sharma, Ramesh, E-mail: ckparadise@gmail.com, E-mail: sharmarameshfgiet@gmail.com [Dept. of Physics, Feroze Gandhi Institute of Engineering & Technology, Raebareli-229001, U.P India (India)

2016-05-06

We have studied the structural stability, electronic structure, optical properties and thermoelectric properties of doped BaHfO{sub 3} by full potential linearized augmented plane wave (FP-LAPW) method. The electronic structure of BaHfO{sub 3} doped with Sr shows enhances the indirect band gaps of 3.53 eV, 3.58 eV. The charge density plots show strong ionic bonding in Ba-Hf, and ionic and covalent bonding between Hf and O. Calculations of the optical spectra, viz., the dielectric function, refractive index and extinction coefficient are performed for the energy range are calculated and analyzed. Thermoelectric properties of semi conducting are also reported first time. The doped BaHfO{sub 3} is approximately wide band gap semiconductor with the large p-type Seebeck coefficient. The power factor of BaHfO{sub 3} is increased with Sr doping, decreases because of low electrical resistivity and thermal conductivity.

Relationship between CCR and NT-proBNP in Chinese HF patients, and their correlations with severity of HF.

Science.gov (United States)

Lu, Zhigang; Wang, Bo; Wang, Yunliang; Qian, Xueqing; Zheng, Wei; Wei, Meng

2014-01-01

To evaluate the relationship between creatinine clearance rate (CCR) and the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in heart failure (HF) patients and their correlations with HF severity. Two hundred and one Chinese patients were grouped according to the New York Heart Association (NYHA) classification as NYHA 1-2 and 3-4 groups and 135 cases out of heart failure patients as control group. The following variables were compared among these three groups: age, sex, body mass index (BMI), smoking status, hypertension, diabetes, NT-proBNP, creatinine (Cr), uric acid (UA), left ventricular end-diastolic diameter (LVEDD), and CCR. The biomarkers of NT-proBNP, Cr, UA, LVEDD, and CCR varied significantly in the three groups, and these variables were positively correlated with the NHYA classification. The levels of NT-proBNP and CCR were closely related to the occurrence of HF and were independent risk factors for HF. At the same time, there was a significant negative correlation between the levels of NT-proBNP and CCR. The area under the receiver operating characteristic curve suggested that the NT-proBNP and CCR have high accuracy for diagnosis of HF and have clinical diagnostic value. NT-proBNP and CCR may be important biomarkers in evaluating the severity of HF.

HF i dag

DEFF Research Database (Denmark)

Lindstrøm, Maria Duclos; Simonsen, Birgitte

2008-01-01

Notatet er lavet på baggrund af uddannelsesbiografiske dybdeinterviews med kursister på toårigt HF. Indenfor rammerne af en pilotundersøgelse identificerer notatet fire gennemgående profiler: De pragmatiske, de fagligt usikre, second chance-kursisterne, og de HF-kursister, som har HF som first...

Human Factors Principles in Design of Computer-Mediated Visualization for Robot Missions

Energy Technology Data Exchange (ETDEWEB)

David I Gertman; David J Bruemmer

2008-12-01

With increased use of robots as a resource in missions supporting countermine, improvised explosive devices (IEDs), and chemical, biological, radiological nuclear and conventional explosives (CBRNE), fully understanding the best means by which to complement the human operator’s underlying perceptual and cognitive processes could not be more important. Consistent with control and display integration practices in many other high technology computer-supported applications, current robotic design practices rely highly upon static guidelines and design heuristics that reflect the expertise and experience of the individual designer. In order to use what we know about human factors (HF) to drive human robot interaction (HRI) design, this paper reviews underlying human perception and cognition principles and shows how they were applied to a threat detection domain.

G-factor for the K-6, Jsup(π) = 6+ isomer in 178Hf

International Nuclear Information System (INIS)

Faestermann, T.; Haeusser, O.; Ward, D.; Andrews, H.R.; Alexander, T.K.; Horn, D.

1978-01-01

High-K isomers are prevalent towards the end of the rare-earth region of deformed nuclei where the valence particles fill high Ω orbitals. Very little is known about the g-factors for these isomers mainly because in the half-life range encountered, 50 ns-50 μs, quadrupole and paramagnetic relaxation effects can destroy the nuclear alignment very rapidly. In 178 Hf a Isub(π)K=6 + 6 isomer with a half-life of 78 ns has recently been found. It decays predominantly to the ground band (K=O) 6 + and 4 + levels with gamma rays of 921.8 keV and 1247.3 keV respectively. The authors have measured the g-factor of this isomer with the method of perturbed angular distributions. (Auth.)

Comparison of HfCl{sub 4}, HfI{sub 4}, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO{sub 2} films deposited by ALD: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Cortez-Valadez, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190 Hermosillo, Son. (Mexico); Fierro, C.; Farias-Mancilla, J.R. [Instituto de Ingeniería y Tecnología, Departamento de Física y Matemáticas, Universidad Autónoma de Ciudad Juárez, Av. del Charro 450, Cd. Juárez C.P. 32310, Chihuahua (Mexico); Vargas-Ortiz, A. [Universidad Autónoma de Sinaloa, Facultad de Ingeniería Mochis, Ciudad Universitaria, C.P. 81223 Los Mochis, Sinaloa (Mexico); Flores-Acosta, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190 Hermosillo, Son. (Mexico); Ramírez-Bon, R. [Centro de Investigación y Estudios Avanzados del IPN, Unidad Querétaro, Apdo. Postal 1-798, 76001 Querétaro, Qro. (Mexico); Enriquez-Carrejo, J.L. [Instituto de Ingeniería y Tecnología, Departamento de Física y Matemáticas, Universidad Autónoma de Ciudad Juárez, Av. del Charro 450, Cd. Juárez C.P. 32310, Chihuahua (Mexico); and others

2016-06-15

Highlights: • Hafnium oxide growth on Si(100) by atomic layer deposition was simulated. • The interface structure was considered as silicate and silicide. • The interface was studied employing DFT. • TDMA-Hf precursor show better interface stability. - Abstract: The final structure of HfO{sub 2} films grown by atomic layer deposition (ALD) after reaction with OH{sup −} ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl{sub 4} (hafnium tetrachloride), HfI{sub 4} (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO–H was studied employing the B3LYP (Becke 3-parameter, Lee–Yang–Parr) hybrid functional and the PBE (Perdew–Burke–Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

Wet etching characteristics of a HfSiON high-k dielectric in HF-based solutions

International Nuclear Information System (INIS)

Li Yongliang; Xu Qiuxia

2010-01-01

The wet etching properties of a HfSiON high-k dielectric in HF-based solutions are investigated. HF-based solutions are the most promising wet chemistries for the removal of HfSiON, and etch selectivity of HF-based solutions can be improved by the addition of an acid and/or an alcohol to the HF solution. Due to densification during annealing, the etch rate of HfSiON annealed at 900 0 C for 30 s is significantly reduced compared with as-deposited HfSiON in HF-based solutions. After the HfSiON film has been completely removed by HF-based solutions, it is not possible to etch the interfacial layer and the etched surface does not have a hydrophobic nature, since N diffuses to the interface layer or Si substrate formation of Si-N bonds that dissolves very slowly in HF-based solutions. Existing Si-N bonds at the interface between the new high-k dielectric deposit and the Si substrate may degrade the carrier mobility due to Coulomb scattering. In addition, we show that N 2 plasma treatment before wet etching is not very effective in increasing the wet etch rate for a thin HfSiON film in our case. (semiconductor technology)

Do surgeon interviewers have human factor-related issues during the long day UK National Trauma and Orthopaedic specialty recruitment process?

Science.gov (United States)

Scrimgeour, D S G; Higgins, J; Bucknall, V; Arnett, R; Featherstone, C R; Cleland, J; Lee, A J; Brennan, P A

2018-03-05

The role that human factors (HF) play in contributing to medical error is increasingly being recognised by healthcare professionals. Surprisingly, much less is known about the possible effects of HF including boredom, fatigue and organisational influences, on performance outside of the clinical environment such as examining or assessing candidates in other high stakes situations. The authors used a validated 38 response questionnaire based around the HF analysis and classification system (HFACS) to assess factors including stress and pressure, care and support and working within the rules for surgeon interviewers at the UK national trainee selection process in Trauma and Orthopaedic surgery. 121 completed questionnaires were analysed (86% response rate). No statistically significant differences were found between interviewer experience, grade or role at the interview and the mean scores obtained for all four factor items. Overall interviewers had a positive experience during national selection with mean factor scores ranging from 3.80 to 3.98 (out of a maximum satisfaction score of 5). Careful planning by organisations and recognising the importance of the human element are essential to ensure assessors are looked after properly during high stakes assessment processes. Our data suggests that a positive experience for examiners is likely to benefit candidate performance and contribute to a fair and reliable recruitment process. The relationship between examiner experience and candidate performance merits further investigation. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Microhardness evaluation alloys Hf-Si-B; Avaliacao de microdureza de ligas Hf-Si-B

Energy Technology Data Exchange (ETDEWEB)

Gigolotti, Joao Carlos Janio; Costa, Eliane Fernandes Brasil [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Nunes, Carlos Angelo; Rocha, Elisa Gombio; Coelho, Gilberto Carvalho, E-mail: carlosjanio@uol.com.br, E-mail: eliane-costabrasi@hotmail.com, E-mail: cnunes@demar.eel.usp.br, E-mail: elisarocha@alunos.eel.usp.br, E-mail: coelho@demar.eel.usp.br [Universidade de Sao Paulo (USP), Lorena, SP (Brazil)

2014-08-15

The technological advance has generated increasing demand for materials that can be used under high temperature, what includes intermetallic MR-Si-B (MR = refractory metal) alloys with multiphase structures, that can also be applied in oxide environments. Thus, this work had for objective the micro hardness study of the Hf-Si-B system alloys, heat treated at 1600 deg C, in the Hf rich region. Hf-Si-B alloys had been produced with blades of Hf (min. 99.8%), Si (min. 99.998%) and B (min. 99.5%), in the voltaic arc furnace and heat treated at 1600 deg C under argon atmosphere. The relationship of the phases had been previously identified by X-ray diffraction and contrast in backscattered electron imaging mode. The alloys had their hardness analyzed by method Vickers (micro hardness) with load of 0.05 kgf and 0.2 kgf and application time of 20 s. The results, obtained from the arithmetic mean of measurements for each alloy on the heterogeneous region, showed a mean hardness of 11.08 GPA, with small coefficient of variation of 3.8%. The borides HfB2 (19.34 GPa) e HfB - 11.76 GPa, showed the hardness higher than the silicides Hf2Si (8.57 GPa), Hf5Si3 (9.63 GPa), Hf3Si2 (11.66 GPa), Hf5Si4 (10.00 GPa), HfSi (10.02 GPa) e HfSi2 (8.61 GPa). (author)

[Human factors and crisis resource management: improving patient safety].

Science.gov (United States)

Rall, M; Oberfrank, S

2013-10-01

A continuing high number of patients suffer harm from medical treatment. In 60-70% of the cases the sources of harm can be attributed to the field of human factors (HFs) and teamwork; nevertheless, those topics are still neither part of medical education nor of basic and advanced training even though it has been known for many years and it has meanwhile also been demonstrated for surgical specialties that training in human factors and teamwork considerably reduces surgical mortality.Besides the medical field, the concept of crisis resource management (CRM) has already proven its worth in many other industries by improving teamwork and reducing errors in the domain of human factors. One of the best ways to learn about CRM and HFs is realistic simulation team training with well-trained instructors in CRM and HF. The educational concept of the HOTT (hand over team training) courses for trauma room training offered by the DGU integrates these elements based on the current state of science. It is time to establish such training for all medical teams in emergency medicine and operative care. Accompanying safety measures, such as the development of a positive culture of safety in every department and the use of effective critical incident reporting systems (CIRs) should be pursued.

HF/DF chemical labs

International Nuclear Information System (INIS)

Meinzer, R.A.

1987-01-01

This paper provides the essential details to understand and design HF/DF and related types of chemical lasers. The basic operation of the HF/DF chemical laser is described. The details of the excitation chemistry are presented and the pertinent laser physics is described. A description of the various laser components is given and the analytical models for the HF/DF chemical laser are discussed. A brief description of the chain reaction HF/DF chemical laser is offered

HF laser

International Nuclear Information System (INIS)

Suzuki, Kazuya; Iwasaki, Matae

1977-01-01

A review is made of the research and development of HF chemical laser and its related work. Many gaseous compounds are used as laser media successfully; reaction kinetics and technological problems are described. The hybrid chemical laser of HF-CO 2 system and the topics related to the isotope separation are also included. (auth.)

A human fecal contamination score for ranking recreational sites using the HF183/BacR287 quantitative real-time PCR method.

Science.gov (United States)

Cao, Yiping; Sivaganesan, Mano; Kelty, Catherine A; Wang, Dan; Boehm, Alexandria B; Griffith, John F; Weisberg, Stephen B; Shanks, Orin C

2018-01-01

Human fecal pollution of recreational waters remains a public health concern worldwide. As a result, there is a growing interest in the application of human-associated fecal source identification quantitative real-time PCR (qPCR) technologies for water quality research and management. However, there are currently no standardized approaches for field implementation and interpretation of qPCR data. In this study, a standardized HF183/BacR287 qPCR method was combined with a water sampling strategy and a novel Bayesian weighted average approach to establish a human fecal contamination score (HFS) that can be used to prioritize sampling sites for remediation based on measured human waste levels. The HFS was then used to investigate 975 study design scenarios utilizing different combinations of sites with varying sampling intensities (daily to once per week) and number of qPCR replicates per sample (2-14 replicates). Findings demonstrate that site prioritization with HFS is feasible and that both sampling intensity and number of qPCR replicates influence reliability of HFS estimates. The novel data analysis strategy presented here provides a prescribed approach for the implementation and interpretation of human-associated HF183/BacR287 qPCR data with the goal of site prioritization based on human fecal pollution levels. In addition, information is provided for future users to customize study designs for optimal HFS performance. Published by Elsevier Ltd.

Nuclear Factor kappa B is required for the production of infectious human herpesvirus 8 virions

Directory of Open Access Journals (Sweden)

Negin N Blattman

2014-04-01

Full Text Available Human herpesvirus 8 (HHV8 infection leads to potent activation of nuclear factor kappa B (NFB in primary and transformed cells. We used recombinant HHV8 (rKSHV.219 expressing green fluorescent protein under the constitutive cellular promoter elongation factor 2 and red fluorescent protein under an early HHV8 lytic gene promoter T1.1, to monitor replication during infection of human foreskin fibroblasts (HF, noting changes in NFB activity. In primary HF, NFB levels do not affect HHV8 ability to establish infection or maintain latency. Furthermore, there was no effect on the percent of cells undergoing reactivation from latency, and there were similar numbers of released and cell associated HHV8 viral particles following reactivation in the presence of inhibitors. Reactivation of HHV8 in latently infected HF in the presence of NFB inhibitors resulted in production of viral particles that did not efficiently establish infection, due to deficiencies in binding and/or entry into normally permissive cells. Exogenous expression of glycoprotein M, an envelope protein involved in viral binding and entry was able to partially overcome the deficiency induced by NFB inhibitors. Our data indicate that in primary cells, NFB is not required for infection, establishment of latency, or entry into the lytic cycle, but is required for the expression of virion associated genes involved in the initial steps of virion infectivity. These studies suggest that strategies to inhibit NFB may prevent HHV8 spread and should be considered as a potential therapeutic target for preventing HHV8 associated diseases.

SEMICONDUCTOR TECHNOLOGY: Wet etching characteristics of a HfSiON high-k dielectric in HF-based solutions

Science.gov (United States)

Yongliang, Li; Qiuxia, Xu

2010-03-01

The wet etching properties of a HfSiON high-k dielectric in HF-based solutions are investigated. HF-based solutions are the most promising wet chemistries for the removal of HfSiON, and etch selectivity of HF-based solutions can be improved by the addition of an acid and/or an alcohol to the HF solution. Due to densification during annealing, the etch rate of HfSiON annealed at 900 °C for 30 s is significantly reduced compared with as-deposited HfSiON in HF-based solutions. After the HfSiON film has been completely removed by HF-based solutions, it is not possible to etch the interfacial layer and the etched surface does not have a hydrophobic nature, since N diffuses to the interface layer or Si substrate formation of Si-N bonds that dissolves very slowly in HF-based solutions. Existing Si-N bonds at the interface between the new high-k dielectric deposit and the Si substrate may degrade the carrier mobility due to Coulomb scattering. In addition, we show that N2 plasma treatment before wet etching is not very effective in increasing the wet etch rate for a thin HfSiON film in our case.

HF-laser program

International Nuclear Information System (INIS)

Anon.

1978-01-01

Sandia's HF-laser program for FY 77 and FY 78 was revised in June 1977 in order to meet several new program milestones. Research progress is reported on: objective of HF oscillator-amplifier studies using H 2 -F 2 gas mixtures; characteristics of large-volume oscillator using H 2 -F 2 mixtures; characteristics of large-volume amplifier using H 2 -F 2 mixtures; experimental results of the oscillator-amplifier study; objective of high-quality discharge-initiated SF 6 -HI oscillator-preamplifier system; pin-discharge-initiated oscillator and first beam expander; fast-discharge-initiated preamplifiers; reflecting beam expanders for oscillator-preamplifier system; beam quality of discharge-initiated oscillator-preamplifier system; short pulse option for discharge initiated SF 6 -HI system; H 2 -F 2 electron-beam-initiated oscillator-preamplifier system; chamber for HF-laser focusing experiments; computer study of parasitic oscillations in HF amplifiers and oscillators; kinetics upgrade of HF-laser code; repetitivey ignited flowing H 2 -F 2 -O 2 mixtures; spontaneous detonations in multiatmosphere H 2 -F 2 -O 2 mixtures; high-pressure H 2 -F 2 laser studies; and time sequenced energy extraction on the high xenon laser

High-aspect-ratio HfC nanobelts accompanied by HfC nanowires: Synthesis, characterization and field emission properties

Energy Technology Data Exchange (ETDEWEB)

Tian, Song, E-mail: tiansong22@126.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); School of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Hejun, E-mail: lihejun@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China)

2017-04-30

Highlights: • HfC naobelts accompanied by HfC nanowires were synthesized by a catalytic CVD method. • HfC nanobelts as a novel structure of HfC ceramic are reported for the first time. • HfC nanobelts have 100–200 μm in lengths and reach up to 10 μm in widths. • The synthesized product is promising field nanoemitters. - Abstract: As a key refractory carbide, hafnium carbide (HfC) is commonly used as structural materials while the field emission (FE) application of HfC in the field of vacuum microelectronics is almost the only one for functional material purposes. Based on its outstanding physical and chemical characteristics, HfC is identified as a potential candidate with satisfactory mechanical properties and long-term and/or high-temperature FE stability for future applications in high-performance field emitters. However, the development of HfC in various FE applications is hindered because it is not facile to fabricate large-scale low-dimensional HfC field nanoemitters. Herein, High-aspect-ratio HfC nanobelts accompanied by HfC nanowires were synthesized on a large scale by a traditional and simple catalytic chemical vapor deposition (CVD) method. Classical vapor–liquid–solid (VLS) theory was employed to explain the growth of the HfC nanowires and nanobelts along axial direction. The thin HfO{sub 2} shell and thin C layer surrounding the nanostructures might give rise to the diameter fluctuation of HfC nanowires and the width increase of HfC nanobelts in lateral direction. Field emission results show that the high-aspect-ratio HfC nanobelts accompanied by the nanowires are promising field nanoemitters, which exhibit excellent field emission properties with a fairly low turn-on field of ∼1.5 V μm{sup −1} and a low current fluctuation less than ∼10%. This suggests that HfC ceramics with high-aspect-ratio nanostructures are ideal cathode material for various field emission applications.

Determination of the rate of HF hydration and the effects of HF on moisture condensation

International Nuclear Information System (INIS)

McCulla, W.H.

1982-01-01

There were four basic questions addressed in this report that relate to the HF interaction in the environment. As to whether HF hydrates in the vapor phase and what the rate of that hydration is, there seems ample evidence that HF hydrates readily in the vapor phase and the rate of that hydration is very fast, i.e., dHF/dt greater than or equal to 25 torr sec -1 . Concerning under what conditions condensation of the hydrate will occur and whether a third body is required for condensation, it was found that HF does effect the dew point or condensation of water and data was presented indicating the extent of that effect. It was also determined that condensation will occur without a third body present. Thus, in attempting to model an HF release for the Safety Analysis Report the hydration of HF and the subsequent heat released may be treated as occurring instantaneously; but the ultimate disposition of the HF will be strongly dependent upon the environmental conditions at the time of the release

Determination of the rate of HF hydration and the effects of HF on moisture condensation

Energy Technology Data Exchange (ETDEWEB)

McCulla, W H

1982-04-30

There were four basic questions addressed in this report that relate to the HF interaction in the environment. As to whether HF hydrates in the vapor phase and what the rate of that hydration is, there seems ample evidence that HF hydrates readily in the vapor phase and the rate of that hydration is very fast, i.e., dHF/dt greater than or equal to 25 torr sec/sup -1/. Concerning under what conditions condensation of the hydrate will occur and whether a third body is required for condensation, it was found that HF does effect the dew point or condensation of water and data was presented indicating the extent of that effect. It was also determined that condensation will occur without a third body present. Thus, in attempting to model an HF release for the Safety Analysis Report the hydration of HF and the subsequent heat released may be treated as occurring instantaneously; but the ultimate disposition of the HF will be strongly dependent upon the environmental conditions at the time of the release.

High-K rotational bands in {sup 174}Hf and {sup 175}Hf

Energy Technology Data Exchange (ETDEWEB)

Gjoerup, N L; Sletten, G [The Niels Bohr Institute, Roskilbe (Denmark); Walker, P M [Surrey Univ., Guildford (United Kingdom). Dept. of Physics; Bentley, M A [Daresbury Lab. (United Kingdom); Cullen, D M; Sharpey-Schafer, J F; Fallon, P; Smith, G [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.

1992-08-01

High sensitivity experiments with {sup 48}Ca, {sup 18}O and {sup 9}Be induced reactions using the ESSA-30, TESSA-3 and NORDBALL arrays have provided extensive new information on the high spin level structures of {sup 174}Hf and {sup 175}Hf. During the series of experiments, several new bands have been found and most known bands have been extended considerably. Spin and excitation energy ranges for {sup 174}Hf are now {approx} 35 {Dirac_h} and {approx} 13 MeV, respectively, and for {sup 175}Hf ranges are {approx} 30 {Dirac_h} and {approx} 7 MeV. respectively. Several new high-K structures have been found in {sup 174}Hf and the structure of these and the already known high-K bands in both nuclei together with the new Tilted Axis Cranking approach might explain the small K-hindrances observed for K-isomers in this region. (author). 8 refs., 2 figs.

Beta decomposition processes in Hf-rich Hf--Nb alloys

International Nuclear Information System (INIS)

Jones, W.B.; Taggart, R.; Polonis, D.H.

1978-01-01

The decomposition of the bcc β-phase by both athermal and isothermal processes has been investigated in Hf-rich Hf--Nb alloys. An all β-phase structure is retained in chill-cast alloys containing 30 to 50 at.% Nb (Cb), although electron diffraction streaking effects and the behavior of the temperature coefficient of electrical resistivity indicate the presence of a bcc lattice instability similar to that reported in solute lean Ti and Zr alloys. Aging a Hf 0 . 65 Nb 0 . 35 alloy at 400 and 600 0 C resulted in the direct precipitation of a fine dispersion of α-phase needles; this morphology differs from the discs of transition α (α/sub t/) which Carpenter et al observed in Nb-rich Nb 0 . 68 Hf 0 . 32 . During continued aging, the needles grow selectively to form colonies or groups of needles in which both the individual needles and the groups of needles have major axes aligned along (110)/sub β/ type directions. The initial α-phase particles exhibit the Burgers orientation relationship with the parent matrix; continued aging changes the electron diffraction patterns in a way that is similar to that observed in aged Ti--Mo and Ti--Mo--Al alloys where they were attributed to the α-phase having a different crystallographic relationship to the β-phase (Type 2 α-phase). The observed changes in the electron diffraction patterns of aged Hf 0 . 65 Nb 0 . 35 cannot be described as resulting from strained Burgers α-phase

High resolution TDPAC measurements on 181Ta in Hf2Fe, Hf2Co and Hf2Rh at high temperature

International Nuclear Information System (INIS)

Cekic, B.; Koicki, S.; Ivanovic, N.; Manasijevic, M.; Koteski, V.; Marjanovic, D.

1998-01-01

The time differential perturbed angular correlation measurements (TDPAC-method ) on 181 Ta ion probe in Hf 2 Co, Hf 2 Fe and Hf 2 Rh intermetallic compounds have been performed at 1170 K, using a fast - slow time spectrometer consisting of two BaF 2 detectors. The results of the measurements show the presence of two independent electric quadrupole interactions, compatible with the crystalline structure of these polycrystalline compounds. (authors)

Isothermal cross-sections of Hf-Sc-Ga(800 deg C) and Hf-Ti-Ga (750 deg C) phase diagrams

International Nuclear Information System (INIS)

Markiv, V.Ya.; Belyavina, N.N.

1981-01-01

Isothermal cross sections of Hf-Sc-Ga (800 deg C) and Hf-Ti-Ga (750 deg C) state diagrams are plotted. The existence of two ternary Hfsub(0.1-0.8)Scsub(0.9)-sub(0.2)Ga and Hfsub(0.8)Scsub(0.2)Gasub(3) phases is stated in the Hf-Sc-Ga system. The crystal structure of these compounds investigated by the powder method belongs to the structural α-MoB and ZrAl 3 types respectively. Continuous rows of (Hf, Sc 5 Ga 5 , (Hf, Ti)Ga 3 and (Hf, Ti)Ga 2 solid solutions are formed in the investigated systems. Essential quantity of the third component dissolve binary Sc 5 Ga 4 , Sc 2 Ga 3 (15 and 30 at % Hf respectively), Hf 5 Ga 4 , HfGa 2 (20, 10 at. % Sc), Hf 5 Ga 4 , HfGa, Hf 5 Ga 3 , Hf 2 Ga 3 (48, 30, 46, 20 at. % Ti) gallides [ru

High-temperature x-ray diffraction study of HfTiO4-HfO2 solid solutions

International Nuclear Information System (INIS)

Carpenter, D.A.

1975-01-01

High-temperature x-ray diffraction techniques were used to determine the axial thermal expansion curves of HfTiO 4 -HfO 2 solid solutions as a function of composition. Data show increasing anisotropy with increasing HfO 2 content. An orthorhombic-to-monoclinic phase transformation was detected near room temperature for compositions near the high HfO 2 end of the orthorhombic phase field and for compositions within the two-phase region (HfTiO 4 solid solution plus HfO 2 solid solution). An orthorhombic-to-cubic phase transformation is indicated by data from oxygen-deficient materials at greater than 1873 0 K. (U.S.)

Self-diffusion of Er and Hf inpure and HfO2-doped polycrystalline Er2O3

International Nuclear Information System (INIS)

Scheidecker, R.W.

1979-01-01

Using a tracer technique, self-diffusion of Er and Hf was measured over the approximate temperature interval of 1600 to 1970 0 C in pure and HfO 2 -doped polycryatalline Er 2 O 3 . Up to about 10 m/o HfO 2 dopant level, the Er self-diffusion coefficients followed a relationship based on cation vacancies. Above 10 m/o HfO 2 , deviation from this relationship occurred, apparently due to clustering of cation vacancies and oxygen interstitials around the dopant hafnia ion. The activation energy for the self-diffusion of Er in pure Er 2 O 3 was 82.2 Kcal/mole and increased with the HfO 2 dopant level present. Self-diffusion of Hf was measured in pure Er 2 O 3 having two impurity levels, and a separation of the grain boundary. The volume diffusion of Hf showed both extrinsic and intrinsic behavior with the transition temperature increasing with the impurity level present in Er 2 O 3 . The activation energy for Hf volume diffusion in the intrinsic region was high, i.e. 235 -+ 9.5 Kcal/mole. The grain boundary diffusion was apparently extrinsic over the entire temperature interval Very low Hf self diffusion rates were found in both pure and HfO 2 doped Er 2 O 3 compositions. Despite a clustering effect, the HfO 2 dopant increased the Hf volume diffusion coefficients

Reconciliation of the excess 176Hf conundrum in meteorites: Recent disturbances of the Lu-Hf and Sm-Nd isotope systematics

Science.gov (United States)

Bast, Rebecca; Scherer, Erik E.; Sprung, Peter; Mezger, Klaus; Fischer-Gödde, Mario; Taetz, Stephan; Böhnke, Mischa; Schmid-Beurmann, Hinrich; Münker, Carsten; Kleine, Thorsten; Srinivasan, Gopalan

2017-09-01

The long-lived 176Lu-176Hf and 147Sm-143Nd radioisotope systems are commonly used chronometers, but when applied to meteorites, they can reveal disturbances. Specifically, Lu-Hf isochrons commonly yield dates up to ∼300 Myr older than the solar system and varying initial 176Hf/177Hf values. We investigated this problem by attempting to construct mineral and whole rock isochrons for eucrites and angrites. Meteorites from different parent bodies exhibit similar disturbance features suggesting that a common process is responsible. Minerals scatter away from isochron regressions for both meteorite classes, with low-Hf phases such as plagioclase and olivine typically being most displaced above (or left of) reference isochrons. Relatively Hf-rich pyroxene is less disturbed but still to the point of steepening Lu-Hf errorchrons. Using our Lu-Hf and Sm-Nd data, we tested various Hf and Lu redistribution scenarios and found that decoupling of Lu/Hf from 176Hf/177Hf must postdate the accumulation of significant radiogenic 176Hf. Therefore early irradiation or diffusion cannot explain the excess 176Hf. Instead, disturbed meteorite isochrons are more likely caused by terrestrial weathering, contamination, or common laboratory procedures. The partial dissolution of phosphate minerals may predominantly remove rare earth elements including Lu, leaving relatively immobile and radiogenic Hf behind. Robust Lu-Hf (and improved Sm-Nd) meteorite geochronology will require the development of chemical or physical methods for removing unsupported radiogenic Hf and silicate-hosted terrestrial contaminants without disturbing parent-daughter ratios.

Clinical trials update from the Heart Failure Society of America Meeting 2009: FAST, IMPROVE-HF, COACH galectin-3 substudy, HF-ACTION nuclear substudy, DAD-HF, and MARVEL-1.

Science.gov (United States)

Lainscak, Mitja; Coletta, Alison P; Sherwi, Nasser; Cleland, John G F

2010-02-01

This article presents findings and a commentary on late-breaking trials presented during the meeting of the Heart Failure Society of America in September 2009. Unpublished reports should be considered as preliminary, since analyses may change in the final publication. The FAST trial showed somewhat better performance of intrathoracic impedance for prediction of deterioration in patients with heart failure (HF) when compared with daily weighing. The IMPROVE-HF study reported the benefits of education on the management of patients with systolic HF. Galectin-3 appeared a useful method for improving risk stratification of patients with chronic HF in a substudy of the COACH trial. A nuclear substudy of the HF-ACTION trial failed to demonstrate that resting myocardial perfusion imaging, a measure of myocardial scar and viability, was clinically useful. A small randomized controlled trial (DAD-HF) suggested that the use of low-dose dopamine in patients with acutely decompensated HF was associated with less deterioration in renal function and less hypokalaemia. The MARVEL-1 trial raises further concerns about the safety of myoblast transplantation in ischaemic HF.

A new class of materials with promising thermoelectric properties: MNiSn (M=Ti, Zr, Hf)

Energy Technology Data Exchange (ETDEWEB)

Hohl, H; Ramirez, A P; Kaefer, W; Fess, K; Thurner, Ch; Kloc, Ch; Bucher, E

1997-07-01

TiNiSn, ZrNiSn and HfNiSn are members of a large group of intermetallic compounds which crystallize in the cubic MgAgAs-type structure. Polycrystalline samples of these compounds have been prepared and investigated for their thermoelectric properties. With thermopowers of about {minus}200 {micro}V/K and resistivities of a few m{Omega}cm, power factors S{sup 2}/{rho} as high as 38 {micro}W/K{sup 2}cm were obtained at 700 K. These remarkably high power factors are, however, accompanied by a thermal conductivity, solid solutions Zr{sub 1{minus}x}Hf{sub x}NiSn, Zr{sub 1{minus}x}Ti{sub x}NiSn, and Hf{prime}{sub 1{minus}x}Ti{sub x}NiSn were formed. The figure of merit of Zr{sub 0.5}Hf{sub 0.5}NiSn at 700 K (ZT = 0.41) exceeds the end members ZrNiSn (ZT = 0.26) and HfNiSn (ZT = 0.22).

Ab initio theoretical study of dipole-bound anions of molecular complexes: (HF)3- and (HF)4- anions

Science.gov (United States)

Ramaekers, Riet; Smith, Dayle M. A.; Smets, Johan; Adamowicz, Ludwik

1997-12-01

Ab initio calculations have been performed to determine structures and vertical electron detachment energy (VDE) of the hydrogen fluoride trimer and tetramer anions, (HF)3- and (HF)4-. In these systems the excess electron is bound by the dipole field of the complex. It was determined that, unlike the neutral complexes which prefer the cyclic structures, the equilibrium geometries of the anions have "zig-zag" shapes. For both complexes the predicted VDEs are positive [210 meV and 363 meV for (HF)3- and (HF)4-, respectively], indicating that the anions are stable systems with respect to the vertical electron detachment. These results were obtained at the coupled-cluster level of theory with single, double and triple excitations [CCSD(T) method; the triple-excitation contribution in this method is calculated approximately using the perturbation approach] with the anion geometries obtained using the second-order Møller-Plesset perturbation theory (MP2) method. The same approach was also used to determine the adiabatic electron affinities (AEA) of (HF)3 and (HF)4. In addition to the electronic contribution, we also calculated the contributions (using the harmonic approximation) resulting from different zero-point vibration energies of the neutral and anionic clusters. The calculations predicted that while the AEA of (HF)3 is positive (44 meV), the AEA for (HF)4 is marginally negative (-16 meV). This suggests that the (HF)3- anion should be a stable system, while the (HF)4- is probably metastable.

MO-HF-C alloy composition

International Nuclear Information System (INIS)

Whelan, E.P.; Kalns, E.

1987-01-01

This patent describes, as an article of manufacture, a cast ingot of a molybdenum-hafnium-carbon alloy consisting essentially by weight of about 0.6% to about 1% Hf, about 0.045% to about 0.08% C, and the balance essentially molybdenum. The amount of Hf and C present are substantially stoichiometric with respect to HfC and within about +-15% of stoichiometry. The ingot is characterized in that it has a substantially less tendency to crack compared to alloys containing Hf in excess of about 1% by weight and carbon in excess of 0.08% by weight, without substantial diminution in strength properties of the alloy

The rotational excitation of HF by H

Science.gov (United States)

Desrousseaux, Benjamin; Lique, François

2018-06-01

The HF molecule is a key tracer of molecular hydrogen in diffuse interstellar medium (ISM). Accurate modelling of the HF abundance in such media requires one to model its excitation by both radiation and collisions. In diffuse ISM, the dominant collisional partners are atomic and molecular hydrogen. We report quantum time-independent calculations of collisional cross-sections and rate coefficients for the rotational excitation of HF by H. The reactive hydrogen exchange channels are taken into account in the scattering calculations. For the first time, HF-H rate coefficients are provided for temperature ranging from 10 to 500 K. The strongest collision-induced rotational HF transitions are those with Δj = 1, and the order of magnitude of the new HF-H rate coefficients is similar to that of the HF-H2 ones previously computed. As a first application, we simulate the excitation of HF by both H and H2 in typical diffuse ISM. We show that, depending on the rotational transition, hydrogen atoms increase or decrease the simulated excitation temperatures compared to collisional excitation only due to H2 molecules. Such results suggest that the new HF-H collisional data have to be used for properly modelling the abundance of HF in diffuse ISM.

Simultaneous analysis of rotational and vibrational-rotational spectra of DF and HF to obtain irreducible molecular constants for HF

International Nuclear Information System (INIS)

Horiai, Koui; Uehara, Hiromichi

2011-01-01

Graphical abstract: Available rotational and vibrational-rotational spectral lines of DF and HF are analyzed simultaneously using a non-Born-Oppenheimer effective Hamiltonian. Research highlights: → Simultaneous analysis of DF and HF spectral data. → Application of a non-Born-Oppenheimer effective Hamiltonian. → Twenty irreducible molecular constants for HF have been determined. - Abstract: Analytic expressions of corrections for the breakdown of the Born-Oppenheimer approximation to Dunham's Y ij with optimal parameters, i.e., determinable clusters of expansion coefficients, are applied to a data analysis of the rotational and vibrational-rotational transitions of HF reported in the literature. All the available spectral lines of the two isotopologues, DF and HF, are simultaneously fitted to a single set of molecular parameters of HF within experimental errors. Fitting of a data set of 595 spectral transitions for DF and HF has generated only 20 minimal independent parameter values, i.e., 'irreducible' molecular constants of HF, that are sufficient to precisely generate 82 Y ij coefficients and 144 band constants in total: 41 Y ij and 72 band constants each for DF and HF.

The research-practice relationship in ergonomics and human factors--surveying and bridging the gap.

Science.gov (United States)

Chung, Amy Z Q; Shorrock, Steven T

2011-05-01

Significant discord has been aired regarding the widening research-practice gap in several disciplines (e.g. psychology, healthcare), especially with reference to research published in academic journals. The research-practice gap has profound and wide-ranging implications for the adequacy of ergonomics and human factors (E/HF) research and the implementation of research findings into practice. However, no substantive research on this issue has been identified in E/HF. Using an online questionnaire, practitioners were asked about their application of scientific research findings published in peer-reviewed journals and to suggest ways to improve research application in practice. A total of 587 usable responses were collected, spanning 46 countries. This article describes some of the key differences and correlations concerning reading, usefulness and barriers to application among respondents, who varied in terms of organisational type, percentage of work time devoted to application vs. research, society membership and experience. Various solutions proposed by the survey respondents on ways to bridge the research-practice gap are discussed. STATEMENT OF RELEVANCE: The relationship between research and practice in E/HF has long been a subject of discussion, with commentators pointing to tension and possible implications for the adequacy of the discipline. Findings from a cross-sectional survey provide ergonomics practitioners' views on research, leading to discussion of strategies for achieving better integration.

Human factors evaluation of a novel digital medicine system in psychiatry

Directory of Open Access Journals (Sweden)

Peters-Strickland T

2018-02-01

Full Text Available Timothy Peters-Strickland,1 Ainslie Hatch,2 Anke Adenwala,3 Katie Atkinson,4 Benjamin Bartfeld5 1Global Clinical Development, Otsuka Pharmaceutical Development & Commercialization, Inc., Princeton, NJ, USA; 2Clinical Sciences, Digital Medicine, Otsuka America Pharmaceutical, Inc., Princeton, NJ, USA; 3Biostatistics, GfK Custom Research, LLC, Chicago, IL, USA; 4Human Factors Engineering, Proteus Digital Health, Redwood, CA, USA; 5Industrial Design Specialist, Otsuka Pharmaceutical Development & Commercialization, Inc., Princeton, NJ, USA Background: The digital medicine system (DMS, a drug–device combination developed for patients with serious mental illness, integrates adherence measurement with pharmacologic treatment by embedding an ingestible sensor in a pill, allowing for information sharing among patients, health care providers (HCPs, and caregivers via a mobile interface. Studies conducted during the DMS development process aimed to minimize cognitive burden and use-related risks and demonstrated effective use of the technology. Methods: Human factors (HF studies assessed the system’s safe and effective use by the intended users for the intended uses. The patient interface was tested in six formative HF studies followed by a validation study. The HCP/caregiver interface was tested in one study before validation. All tasks critical to safety or necessary for effective use were included. Formative studies identified use-related risks and the causes of use problems to guide design modification. Validation of the patient and HCP/caregiver interfaces assessed risks of the final product. Results: During the patient formative studies, design improvements were made to address problems and mitigate risks thought to be associated with a suboptimal system design or patient understanding of the system. In the validation study of the patient interface, 35 patients attempted 23 performance tasks, for a total of 805 attempts; 783/805 attempts were

Development of HF-systems for electron storage systems

International Nuclear Information System (INIS)

Androsov, V.P.; Karnaukhov, I.M.; Popkov, Yu.P.; Reva, S.N.; Telegin, Yu.N.

1999-01-01

Development of HF systems for electron storages is described. Its final task is construction of 100 kW HF station at 699,3 MHz frequency consisting from low-power HF system, klystron amplifier, wave line for HF power transmission and accelerating section. Functional parameters of HF station are given

Coulomb-nuclear interference measurements of 168Yb, 176Hf, 178Hf, and 180Hf and lifetime measurements in 186Hg

International Nuclear Information System (INIS)

Nettles, W.G.

1979-01-01

Alpha scattering measurements were performed at center-of-mass energies near the Coulomb barrier. These energies allow for nuclear as well as pure Coulomb forces to play a significant role in the excitation process. The interference of these two forces is very sensitive to the sign of the E4 ground-state moment, whereas pure Coulomb excitation is not. Systematics of the E4 moments of the rare earth mass region indicate a transition in the magnitude and sign of the reduced matrix element of the M(E4) operator between 0 + and 4 + states from small and positive to large and negative between Yb and W. Previous Coulomb-nuclear interference measurements show that this reduced matrix element for 180 Hf is large and negative. The present results agree with that conclusion. It is also shown that the above reduced matrix element for 178 Hf, like that of 180 Hf, is large and negative. The small and positive moment (matrix element) for 168 Yb is seen to be consistent with the experimental data. No conclusions are drawn for the E4 moment in 176 Hf. The measurement of nuclear lifetimes shorter than 500 ps requires the use of plastic scintilltor detectors. These detectors, however have very poor energy resolution. A system is described that uses plastic scintillators with a magnetic lens spectrometer for energy selection. The system was used to measure the lifetime of the 522-keV 0 + sate in 186 Hf. A data analysis method using higher-order distribution moments is also presented

Magnetic dipole moments of High-K isomeric states in Hf isotopes

CERN Multimedia

Walters, W; Nishimura, K; Bingham, C R

2007-01-01

It is proposed to make precision measurements of the magnetic moments of 5 multi-quasi-particle K-isomers in Hf nuclei by the Nuclear Magnetic Resonance of Oriented Nuclei (NMR/ON) technique using the NICOLE on-line nuclear orientation facility and exploiting the unique HfF$_{3}$ beams recently available at ISOLDE. Results will be used to extract single-particle and collective g-factors of the isomeric states and their excitations and to shed new light on their structure.

EDF EPR project: operating principles validation and human factor engineering program

International Nuclear Information System (INIS)

Lefebvre, B.; Berard, E.; Arpino, J.-M.

2005-01-01

This article describes the specificities of the operating principles chosen by EDF for the EPR project as a result of an extensive Human Factor Engineering program successfully implemented in an industrial project context. The design process and its achievements benefit of the EDF experience feedback not only in term of NPP operation - including the fully computerized control room of the N4-serie - but also in term of NPP designer. The elements exposed hereafter correspond to the basic design phase of EPR HMI which has been completed and successfully validated by the end of 2003. The article aims to remind the context of the project which basically consists in designing a modern and efficient HMI taking into account the operating needs while relying on proven and reliable technologies. The Human Factor Engineering program implemented merges these both aspects by : 1) being fully integrated within the project activities and scheduling; 2) efficiently taking into account the users needs as well as the feasibility constraints by relying on a multidisciplinary design team including HF specialists, I and C specialists, Process specialists and experienced operator representatives. The resulting design process makes a wide use of experience feedback and experienced operator knowledge to complete largely the existing standards for providing a fully useable and successful design method in an industrial context. The article underlines the design process highlights that largely contribute to the successful implementation of a Human Factor Engineering program for EPR. (authors)

Development of a BN framework for human reliability analysis through virtual simulation

International Nuclear Information System (INIS)

Garg, Vipul; Santhosh, T.V.; Vinod, Gopika; Antony, P.D.

2017-01-01

Humans are an integral part of complex systems such as nuclear power plants and have to play a significant role in ensuring the safety and reliability of these systems. Failure to perform the intended task within the stipulated time by the operator can challenge the safety of the system. Human reliability analysis (HRA) is a widely practiced methodology to estimate the contribution of operator error towards the overall risk to the facility. HRA methods quantify this contribution in terms of human error probability (HEP) accounting for various psychological and physiological factors that influence the performance of the operator. These factors are referred to as human factors (HF), which enhance or degrade the human performance. The paper discusses the use of virtual simulation as a tool to generate the HF data from the virtual model of an in-house experimental facility. This paper also demonstrates the use of multi-attribute utility theory to determine a suitable HRA method amongst several HRA methods to quantify the HEP based on the desired set of HRA attributes. As classical HRA methods, generally, do not address the interactions among the HFs, the Bayesian network technique has been employed in this study to account for HF interactions. (author)

Hf på VUC

DEFF Research Database (Denmark)

Pless, Mette; Hansen, Niels-Henrik Møller

. Konkret har forskningsprojektet 3 mål: At afdække hf-kursisternes tidligere uddannelsesforløb og -erfaringer, før de starter på hf på VUC.At afdække, hvordan mødet med uddannelsens studiemiljø opleves af kursisterne, og ikke mindst kursisternes oplevelse af undervisningsformer, lærere mm.At afdække, hvad...

Human-Machine Communication

International Nuclear Information System (INIS)

Farbrot, J.E.; Nihlwing, Ch.; Svengren, H.

2005-01-01

New requirements for enhanced safety and design changes in process systems often leads to a step-wise installation of new information and control equipment in the control room of older nuclear power plants, where nowadays modern digital I and C solutions with screen-based human-machine interfaces (HMI) most often are introduced. Human factors (HF) expertise is then required to assist in specifying a unified, integrated HMI, where the entire integration of information is addressed to ensure an optimal and effective interplay between human (operators) and machine (process). Following a controlled design process is the best insurance for ending up with good solutions. This paper addresses the approach taken when introducing modern human-machine communication in the Oskarshamn 1 NPP, the results, and the lessons learned from this work with high operator involvement seen from an HF point of view. Examples of possibilities modern technology might offer for the operators are also addressed. (orig.)

The anisotropy of Hf diffusion in α-Zr

International Nuclear Information System (INIS)

Hood, G.M.; Zou, H.; Roy, J.A.; Schultz, R.J.; Matsuura, N.; Jackson, J.A.

1995-07-01

Hf diffusion coefficients (D) have been measured in the temperature interval 870-1100 K, in directions parallel (D pa ) and perpendicular (D pe ) to the c-axis of double-faced, single crystal specimens of both high-purity (HP) and nominally pure (NP) α-Zr single crystals. The diffusion profiles were measured by secondary ion mass spectrometry. Hf diffusion in HP α-Zr is characterised by an activation energy of about 3.0 eV and a pre-exponential factor of about 10 -5 m 2 /s. The anisotropy ratio, D pa /D pe is ∼ 1.0 for the NP specimens. A dependence of D on diffusion time/depth is indicated for some NP experiments on NP Zr. (author). 7 refs., 2 tabs., 3 figs

HfO2 as gate dielectric on Ge: Interfaces and deposition techniques

International Nuclear Information System (INIS)

Caymax, M.; Van Elshocht, S.; Houssa, M.; Delabie, A.; Conard, T.; Meuris, M.; Heyns, M.M.; Dimoulas, A.; Spiga, S.; Fanciulli, M.; Seo, J.W.; Goncharova, L.V.

2006-01-01

To fabricate MOS gate stacks on Ge, one can choose from a multitude of metal oxides as dielectric material which can be deposited by many chemical or physical vapor deposition techniques. As a few typical examples, we will discuss here the results from atomic layer deposition (ALD), metal organic CVD (MOCVD) and molecular beam deposition (MBD) using HfO 2 /Ge as materials model system. It appears that a completely interface layer free HfO 2 /Ge combination can be made in MBD, but this results in very bad capacitors. The same bad result we find if HfGe y (Hf germanides) are formed like in the case of MOCVD on HF-dipped Ge. A GeO x interfacial layer appears to be indispensable (if no other passivating materials are applied), but the composition of this interfacial layer (as determined by XPS, TOFSIMS and MEIS) is determining for the C/V quality. On the other hand, the presence of Ge in the HfO 2 layer is not the most important factor that can be responsible for poor C/V, although it can still induce bumps in C/V curves, especially in the form of germanates (Hf-O-Ge). We find that most of these interfacial GeO x layers are in fact sub-oxides, and that this could be (part of) the explanation for the high interfacial state densities. In conclusion, we find that the Ge surface preparation is determining for the gate stack quality, but it needs to be adapted to the specific deposition technique

Anion exchange behavior of Ti, Zr, Hf, Nb and Ta as homologues of Rf and Db in mixed HF-acetone solutions

International Nuclear Information System (INIS)

Aksenov, N.V.; Bozhikov, G.A.; Starodub, G.Ya.; Dmitriev, S.N.; Filosofov, D.V.; Jon Sun Jin; Radchenko, V.I.; Lebedev, N.A.; Novgorodov, A.F.

2009-01-01

We studied in detail the sorption behavior of Ti, Zr, Hf, Nb and Ta on AG 1 anion exchange resin in HF-acetone mixed solutions as a function of organic cosolvent and acid concentrations. Anion exchange behavior was found to be strongly acetone concentration dependent. The distribution coefficients of Ti, Zr, Hf and Nb increased and those of Ta decreased with increasing content of acetone in HF solutions. With increasing HF concentration, anion exchange equilibrium analysis indicated the formation of fluoride complexes of group-4 elements with charge -3 and Ta with charge -2. For Nb the slope of -2 increased up to -5. Optimal conditions for separation of the elements using AIX chromatography were found. Group-4 elements formed MF 7 3- (M = Ti, Zr, Hf) complexes whose sorption decreased Ti > Hf > Zr in reverse order of complex stability. This fact is of particular interest for studying ion exchange behavior of Rf compared to Ti. The advantages of studying chemical properties of Rf and Db in aqueous HF solutions mixed with organic solvents are briefly discussed

Positron annihilation studies in Hf doped YBCO

International Nuclear Information System (INIS)

Gopalan, P.; Priya, E.R.; Premila, M.; Sundar, C.S.; Gopinathan, K.P.

1992-01-01

The variation of positron lifetime and oxygen stoichiometry as a function of quench temperature has been measured in undoped and 0.5at%, 0.75at%, and 1.0 at% Hf doped YBCO. In both the undoped and Hf doped samples, the lifetime decreases and the oxygen content increases as the quench temperature is lowered from 900degC to 300degC. The lifetime in the tetragonal phase (900degC) decreases with the increase in Hf content, whereas in the orthorhombic phase (450degC) it increases. The difference in lifetime between the tetragonal and orthorhombic phases decreases with the increase in the Hf content. These trends are discussed in terms of the influence of Hf doping on the oxygen content and the positron density distribution in YBCO

COPD predicts mortality in HF: the Norwegian Heart Failure Registry.

Science.gov (United States)

De Blois, Jonathan; Simard, Serge; Atar, Dan; Agewall, Stefan

2010-03-01

Chronic obstructive pulmonary disease (COPD) and chronic heart failure (HF) are common clinical conditions that share tobacco as a risk factor. Our aim was to evaluate the prognostic impact of COPD on HF patients. The Norwegian Heart Failure Registry was used. The study included 4132 HF patients (COPD, n = 699) from 22 hospitals (mean follow-up, 13.3 months). COPD patients were older, more often smokers and diabetics, less often on beta-blockers and had a higher heart rate. They were more often in New York Heart Association (NYHA) Class III or IV (COPD, 63%; no COPD, 51%), although left ventricular ejection fraction (LVEF) distribution was similar. COPD independently predicted death (adjusted hazard ratio [HR], 1.188; 95% CI: 1.015 to 1.391; P = 0.03) along with age, creatinine, NYHA Class III/IV (HR, 1.464; 95% CI: 1.286 to 1.667) and diabetes. beta-blockers at baseline were associated with improved survival in patients with LVEF < or =40% independently of COPD. COPD is associated with a poorer survival in HF patients. COPD patients are overrated in terms of NYHA class in comparison with patients with similar LVEF. Nonetheless, NYHA class remains the strongest predictor of death in these patients. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Ge interactions on HfO2 surfaces and kinetically driven patterning of Ge nanocrystals on HfO2

International Nuclear Information System (INIS)

Stanley, Scott K.; Joshi, Sachin V.; Banerjee, Sanjay K.; Ekerdt, John G.

2006-01-01

Germanium interactions are studied on HfO 2 surfaces, which are prepared through physical vapor deposition (PVD) and by atomic layer deposition. X-ray photoelectron spectroscopy and temperature-programed desorption are used to follow the reactions of germanium on HfO 2 . Germanium chemical vapor deposition at 870 K on HfO 2 produces a GeO x adhesion layer, followed by growth of semiconducting Ge 0 . PVD of 0.7 ML Ge (accomplished by thermally cracking GeH 4 over a hot filament) also produces an initial GeO x layer, which is stable up to 800 K. PVD above 2.0 ML deposits semiconducting Ge 0 . Temperature programed desorption experiments of ∼1.0 ML Ge from HfO 2 at 400-1100 K show GeH 4 desorption below 600 K and GeO desorption above 850 K. These results are compared to Ge on SiO 2 where GeO desorption is seen at 550 K. Exploiting the different reactivity of Ge on HfO 2 and SiO 2 allows a kinetically driven patterning scheme for high-density Ge nanoparticle growth on HfO 2 surfaces that is demonstrated

Electric Field Gradients at Hf and Fe Sites in Hf2Fe Recalculated

International Nuclear Information System (INIS)

Belosevic-Cavor, J.; Cekic, B.; Novakovic, N.; Koteski, V.; Milosevic, Z.

2004-01-01

The electric field gradients (EFG) of the Hf 2 Fe intermetallic compound were calculated using the full-potential linearized augmented plain-wave (FP-LAPW) method as embodied in the WIEN 97 code. The obtained values are compared with other ab-initio calculations and on a qualitative basis with the previously reported experimental data obtained from TDPAC. The calculated results, -23.1.10 21 V/m 2 and 2.7.10 21 V/m 2 for Hf 48f and Fe 32e position, respectively, are in excellent agreement with experimental data (23.4.10 21 V/m 2 and 2.7.10 21 V/m 2 ), better than those reported in earlier calculations. The calculated EFG for Hf 16c position (4.2.10 21 V/m 2 ) is stronger than the experimental one (1.1.10 21 V/m 2 ).

Microstructural characterization of as-cast hf-b alloys

Directory of Open Access Journals (Sweden)

João Carlos Jânio Gigolotti

2012-04-01

Full Text Available An accurate knowledge of several metal-boron phase diagrams is important to evaluation of higher order systems such as metal-silicon-boron ternaries. The refinement and reassessment of phase diagram data is a continuous work, thus the reevaluation of metal-boron systems provides the possibility to confirm previous data from an investigation using higher purity materials and better analytical techniques. This work presents results of rigorous microstructural characterization of as-cast hafnium-boron alloys which are significant to assess the liquid composition associated to most of the invariant reactions of this system. Alloys were prepared by arc melting high purity hafnium (minimum 99.8% and boron (minimum 99.5% slices under argon atmosphere in water-cooled copper crucible with non consumable tungsten electrode and titanium getter. The phases were identified by scanning electron microscopy, using back-scattered electron image mode and X-ray diffraction. In general, a good agreement was found between our data and those from the currently accepted Hafnium-Boron phase diagram. The phases identified are αHfSS and B-RhomSS, the intermediate compounds HfB and HfB2 and the liquide L. The reactions are the eutectic L ⇔ αHfSS + HfB and L ⇔ HfB2 + B-Rhom, the peritectic L + HfB2 ⇔ HfB and the congruent formation of HfB2.

The Thermodynamic Characterization of ZrCo–H, HfCo−H, HfNi−H and Zr{sub 1–x}HfxNi(Co) Alloy–H Systems

Energy Technology Data Exchange (ETDEWEB)

Flanagan, Ted B., E-mail: ted.flanagan@uvm.edu; Noh, Hak; Luo, Suifang

2016-08-25

ZrCo and HfCo intermetallic compounds have the same cubic (CsCl-type) structure and their ternary (Zr{sub 1−x}Hf{sub x})Co alloys are also cubic. ZrNi and HfNi intermetallic compounds have the orthorhombic structure (CrB-type) and the ternary (Zr{sub 1−x}Hf{sub x})Ni alloys also have this structure. Thermodynamic data for hydride formation and decomposition in ZrCo, HfCo and HfNi intermetallic compounds have been determined from reaction calorimetry and from pressure-composition isotherms. Thermodynamic data have been determined for the three ternary alloys: (Zr{sub 0.75}Hf{sub 0.25})Co, (Zr{sub 0.50}Hf{sub 0.50})Co, and (Zr{sub 0.25}Hf{sub 0.75})Co and the four ternary alloys: (Zr{sub 0.875}Hf{sub 0.125})Ni, (Zr{sub 0.75}Hf{sub 0.25})Ni, (Zr{sub 0.50}Hf{sub 0.50})Ni, and (Zr{sub 0.25}Hf{sub 0.75})Ni. This offers the opportunity to learn how the thermodynamic properties of the ternary alloy-H systems change with the stoichiometry of alloys with the same structure. - Highlights: • Calorimetric enthalpies determined for H absorption by ZrCo, HfCo, HfNi are determined. • Ternary alloys, e.g., Zr{sub 1−x}Hf{sub x}Ni, prepared and characterized by x-ray diffraction. • Isotherms for the ternary alloys give thermodynamic parameters for H solution.

High energy HF pulsed lasers

International Nuclear Information System (INIS)

Patterson, E.L.; Gerber, R.A.

1976-01-01

Recent experiments show that pulsed HF lasers are capable of producing high energy with good efficiency. Preliminary experiments show that the laser radiation from the high-gain medium can be controlled with a low-power probe laser beam or with low-level feedback. These results indicate that the HF laser may have potential for second-generation laser fusion experiments

Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada

Science.gov (United States)

Lowery, Claiborne L.E.; Miller, C.F.; Walker, B.A.; Wooden, J.L.; Mazdab, F.K.; Bea, F.

2006-01-01

Zirconium and Hf are nearly identical geochemically, and therefore most of the crust maintains near-chondritic Zr/Hf ratios of ???35-40. By contrast, many high-silica rhyolites and granites have anomalously low Zr/Hf (15-30). As zircon is the primary reservoir for both Zr and Hf and preferentially incorporates Zr, crystallization of zircon controls Zr/ Hf, imprinting low Zr/Hf on coexisting melt. Thus, low Zr/Hf is a unique fingerprint of effective magmatic fractionation in the crust. Age and compositional zonation in zircons themselves provide a record of the thermal and compositional histories of magmatic systems. High Hf (low Zr/ Hf) in zircon zones demonstrates growth from fractionated melt, and Ti provides an estimate of temperature of crystallization (TTiZ) (Watson and Harrison, 2005). Whole-rock Zr/Hf and zircon zonation in the Spirit Mountain batholith, Nevada, document repeated fractionation and thermal fluctuations. Ratios of Zr/Hf are ???30-40 for cumulates and 18-30 for high-SiO2 granites. In zircons, Hf (and U) are inversely correlated with Ti, and concentrations indicate large fluctuations in melt composition and TTiZ (>100??C) for individual zircons. Such variations are consistent with field relations and ion-probe zircon geochronology that indicate a >1 million year history of repeated replenishment, fractionation, and extraction of melt from crystal mush to form the low Zr/Hf high-SiO2 zone. ?? 2006 The Mineralogical Society.

Qualitative ergonomics/human factors research in health care: Current state and future directions.

Science.gov (United States)

Valdez, Rupa Sheth; McGuire, Kerry Margaret; Rivera, A Joy

2017-07-01

The objective of this systematic review was to understand the current state of Ergonomics/Human Factors (E/HF) qualitative research in health care and to draw implications for future efforts. This systematic review identified 98 qualitative research papers published between January 2005 and August 2015 in the seven journals endorsed by the International Ergonomics Association with an impact factor over 1.0. The majority of the studies were conducted in hospitals and outpatient clinics, were focused on the work of formal health care professionals, and were classified as cognitive or organizational ergonomics. Interviews, focus groups, and observations were the most prevalent forms of data collection. Triangulation and data archiving were the dominant approaches to ensuring rigor. Few studies employed a formal approach to qualitative inquiry. Significant opportunities remain to enhance the use of qualitative research to advance systems thinking within health care. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study of Direct-Contact HfO2/Si Interfaces

Directory of Open Access Journals (Sweden)

Noriyuki Miyata

2012-03-01

Full Text Available Controlling monolayer Si oxide at the HfO2/Si interface is a challenging issue in scaling the equivalent oxide thickness of HfO2/Si gate stack structures. A concept that the author proposes to control the Si oxide interface by using ultra-high vacuum electron-beam HfO2 deposition is described in this review paper, which enables the so-called direct-contact HfO2/Si structures to be prepared. The electrical characteristics of the HfO2/Si metal-oxide-semiconductor capacitors are reviewed, which suggest a sufficiently low interface state density for the operation of metal-oxide-semiconductor field-effect-transistors (MOSFETs but reveal the formation of an unexpected strong interface dipole. Kelvin probe measurements of the HfO2/Si structures provide obvious evidence for the formation of dipoles at the HfO2/Si interfaces. The author proposes that one-monolayer Si-O bonds at the HfO2/Si interface naturally lead to a large potential difference, mainly due to the large dielectric constant of the HfO2. Dipole scattering is demonstrated to not be a major concern in the channel mobility of MOSFETs.

Effects of annealing temperature on the characteristics of ALD-deposited HfO2 in MIM capacitors

International Nuclear Information System (INIS)

Jeong, S.-W.; Lee, H.J.; Kim, K.S.; You, M.T.; Roh, Y.; Noguchi, T.; Xianyu, W.; Jung, J.

2006-01-01

We have investigated the annealing effects of HfO 2 films deposited by an atomic layer deposition (ALD) method on the electrical and physical properties in the Si/SiO 2 /Pt/ALD-HfO 2 /Pd metal-insulator-metal (MIM) capacitors. If the annealing temperature for HfO 2 films was restricted below 500 deg. C, an annealing step using a rapid thermal processor (RTP) improves the electrical properties such as the dissipation factor and the dielectric constant. On the other hand, annealing at 700 deg. C degrades the electrical characteristics in general; the dissipation factor increases over the frequency range of 1∼4 MHz, and the leakage current increases up to 2 orders at the low electric field regions. We found that the degradation of electrical properties is due to the grain growth in the HfO 2 film (i.e., poly-crystallization of the film) by the high temperature annealing processing. We suggested that the annealing temperature must be restricted below 500 deg. C to obtain the high quality high-k film for the MIM capacitors

Thermodynamics of HfCl4-KCl molten mixtures containing HfCl4 up to 33.3 mol. per cent

International Nuclear Information System (INIS)

Smirnov, M.V.; Salyulev, A.B.; Kudyakov, V.Ya.

1980-01-01

Based on measurements of saturated vapour pressure in components of melted mixtures of HfCl 4 -KCl, depending on temperature and concentration, calculated are the results of changes in activity coefficients of hafnium tetrachloride and potassium chloride on transition from diluted solutions, where the Henry law is met, to those concentrated where the law is disobeyed. Growth in the activity coefficient of HfCl 4 is due to dissociation of complex groups of HfCl 6 2- into complexes with a lesser number of ligands and decreasing relative binding energy of Hf 4+ -Cl - there. In this case, marked changes take place in partial enthalpy and entropy of hafnium tetrachloride mixing. Similar dependences are observed for potassium chloride, but they are expressed considerably weaker. Evaporation enthalpy and entropy are calculated for HfCl 4 and KCl monomers from their melted mixtures of various concentrations

Crystal structures of KM(AsF6)3 (M2+ = Mg, Co, Mn, Zn), KCu(SbF6)3 and [Co(HF)2]Sr[Sr(HF)]2-[Sr(HF)2]2[AsF6]12

International Nuclear Information System (INIS)

Mazej, Zoran; Goreshnik, Evgeny

2015-01-01

The KM(AsF 6 ) 3 (M 2+ = Mg, Co, Mn, Zn) and KCu(SbF 6 ) 3 compounds crystallize isotypically to previously known KNi(AsF 6 ) 3 . The main features of the structure of these compounds are rings of MF 6 octahedra sharing apexes with AsF 6 octahedra connected into infinite tri-dimensional frameworks. In this arrangement cavities are formed where K + cations are placed. Single crystals of CoSr 5 (AsF 6 ) 12 .8HF were obtained as one of the products after the crystallization of 3KF/CoF 2 /SrF 2 mixture in the presence of AsF 5 in anhydrous HF. The CoSr 5 (AsF 6 ) 12 .8HF is monoclinic, C/2c (No.15), with a = 26.773(5) Aa, b = 10.087(2) Aa, c = 21.141(5) Aa, β = 93.296(13) circle , V = 5699.9(19) Aa 3 at 200 K, and Z = 4. There are three crystallographically non-equivalent Sr 2+ cations in the crystal structure of CoSr 5 (AsF 6 ) 12 .8HF. The Sr1 is coordinated by ten fluorine atoms from eight different [AsF 6 ]- anions, meanwhile Sr2 and Sr3 are bound to nine fluorine atoms provided by one HF and eight AsF 6 units or by two HF and six AsF 6 units, respectively. The Co 2+ is coordinated distorted-octahedrally by six fluorine atoms from two HF molecules and four different AsF 6 units. All those moieties in the crystal structure of [Co(HF) 2 ]Sr[Sr(HF)] 2 [Sr(HF) 2 ] 2 [AsF 6 ] 12 are connected into tridimensional framework. The CoSr 5 (AsF 6 ) 12 .8HF is a unique example of compound where HF molecules are directly bound via fluorine atoms to two different metal centres.

Zirconium Zr and hafnium Hf

International Nuclear Information System (INIS)

Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

1978-01-01

The basic methods for extracting and determining Zr(4) and Hf(4) are described. Diantipyrinemethane and its alkyl homologs selectively extract Zr and Hf from HNO 3 solutions in the presence of nitrates. Zr is selectively extracted with tetraethyldiamide of heptyl phosphoric acid (in benzene) as well as with 2-thenoyltrifluoroacetone (in an acid). The latter reagents is suitable for rapid determination of 95 Zr in a mixture with 95 Nb and other fragments. The complexometric determination of Zr is based on formation of a stable complex of Zr with EDTA. The titration is carried out in the presence of n-sulfobenzene-azo-pyrocatechol, eriochrome black T. The determination is hindered by Hf, fluoride-, phosphate-, oxalate- and tartrate-ions. The method is used for determining Zr in zircon and eudialyte ore. Zr is determined photometrically with the aid of xylenol orange, arsenazo 3 and pyrocatechol violet (in phosphorites). Hf is determined in the presence of Zr photometrically with the aid of xylenol orange or methyl-thymol blue. The method is based on Zr being masked with hydrogen peroxide in the presence of sulfate-ions

PEMISAHAN Zr – Hf SECARA SINAMBUNG MENGGUNAKAN MIXER SETTLER

Directory of Open Access Journals (Sweden)

Dwi Biyantoro

2017-01-01

Full Text Available ABSTRAK PEMISAHAN Zr – Hf SECARA SINAMBUNG MENGGUNAKANMIXER SETTLER. Telah dilakukan pemisahanZr – Hf secara sinambung menggunakan pengaduk pengenap (mixer settler 16 stage. Larutan umpan adalah zirkon nitrat dengan kadar Zr = 30786 ppm dan Hf = 499 ppm. Ekstraktan dipakai adalah solven 60 % TBP dalam kerosen dan larutan scrubbingyang dipakai adalah asam nitrat 1 M. Umpan masuk pada stageke 5 dikontakkan secara berlawanan arah dengan solven masuk pada stage ke 16 dan larutan scrubbing masuk pada stage ke 1. Tujuan penelitian ini adalah memisahkan unsur Zr dan Hf dari hasil olah pasir zirkon menggunakan solven TBP dengan alat mixer settler16 stage. Analisis umpan dan hasil proses pemisahan untuk zirkonium (Zr dilakukan dengan menggunakan alat pendar sinar-X, sedangkananalisis unsur hafnium (Hf menggunakan Analisis Pengaktifan Neutron (APN. Parameter penelitian dilakukan dengan variasi keasaman asam nitrat dalam umpan dan variasi waktu pada berbagai laju pengadukan. Hasil penelitian pemisahan unsur Zr dengan Hf diperolehkondisi optimum pada keasaman umpan 4 N HNO3, keseimbangan dicapai setelah 3jam dan laju pengadukan 3300 rpm. Hasil ekstrak  unsur zirkon (Zr diperoleh kadar sebesar 28577 ppm dengan efisiensi 92,76 % serta kadar pengotor hafnium (Hf sebesar 95 ppm. Kata Kunci: pemisahan Zr, Hf, ekstraksi, mixer settler, alat pendar sinar-X, APN. ABSTRACT SEPARATION of Zr - Hf CONTINUOUSLY USE THE MIXER SETTLER. Separation of Zr - Hf continuously using mixer settler 16 stage has been done. The feed solution is zircon nitrate concentration of Zr = 30786 ppm  and Hf = 499 ppm. As the solvent used extractant 60 % TBP in 40 % kerosene. Nitric acid solution used srubbing 1 M. The feed entered into stage to 5 is contacted with solvents direction on the stage to 16 and the scrubbing solution enter the stage to 1. The purpose of this study is to separate Zr and Hf of the results from the process of zircon sand using solvent TBP using 16 stage

Action mechanism of hydrogen gas on deposition of HfC coating using HfCl{sub 4}-CH{sub 4}-H{sub 2}-Ar system

Energy Technology Data Exchange (ETDEWEB)

Wang, Yalei, E-mail: yaleipm@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China); School of Metallurgy and Environment, Central South University, Changsha, 410083 (China); Li, Zehao [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China); Xiong, Xiang, E-mail: xiongx@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China); Li, Xiaobin [School of Metallurgy and Environment, Central South University, Changsha, 410083 (China); Chen, Zhaoke; Sun, Wei [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China)

2016-12-30

Highlights: • HfC coatings were deposited on C/C composites by LPCVD using HfCl4-CH4-H2-Ar system. • Action mechanism of H2 on structure and growth behavior of HfC coating was studied. • Increased H2 concentration leads to transformation in growth mechanism of coating. - Abstract: Hafnium carbide coatings were deposited on carbon/carbon composites by low pressure chemical vapor deposition using HfCl{sub 4}-CH{sub 4}-H{sub 2}-Ar system. The microstructure, mechanical and ablation resistance performance of HfC coatings deposited with various H{sub 2} concentrations were investigated. The effect of hydrogen gas on the deposition of HfC coating was also discussed. Results show that all of the deposited coatings are composed of single cubic HfC phase, the hydrogen gas acted as a crucial role in determining the preferred orientation, microstructure and growth behavior of HfC coatings. During the deposition process, the gas phase supersaturation of the reaction species can be controlled by adjusting the hydrogen gas concentration. When deposited with low hydrogen gas concentration, the coating growth was dominated by the nucleation of HfC, which results in the particle-stacked structure of HfC coating. Otherwise, the coating growth was dominated by the crystal growth at high hydrogen gas concentration, which leads to the column-arranged structure of HfC coating. Under the ablation environment, the coating C2 exhibits better configurational stability and ablation resistance. The coating structure has a significant influence on the mechanical and ablation resistance properties of HfC coating.

[Simulator-based modular human factor training in anesthesiology. Concept and results of the module "Communication and Team Cooperation"].

Science.gov (United States)

St Pierre, M; Hofinger, G; Buerschaper, C; Grapengeter, M; Harms, H; Breuer, G; Schüttler, J

2004-02-01

Human factors (HF) play a major role in crisis development and management and simulator training can help to train HF aspects. We developed a modular training concept with psychological intensive briefing. The aim of the study was to see whether learning and transfer in the treatment group (TG) with the module "communication and team-cooperation" differed from that in the control group (CG) without psychological briefing ("anaesthesia crisis resource management type course"). A total of 34 residents (TG: n=20, CG: n=14) managed 1 out of 3 scenarios and communication patterns and management were evaluated using video recordings. A questionnaire was answered at the end of the course and 2 months later participants were asked for lessons learnt and behavioral changes. Good communication and medical management showed a significant correlation (r=0.57, p=0.001). The TG showed greater initiative ( p=0.001) and came more often in conflict with the surgeon ( p=0.06). The TG also reported more behavioral changes than the CG 2 months later. The reported benefit of the simulation was training for rare events in the CG, whereas in the TG it was issues of communication and cooperation ( p=0.001). A training concept with psychological intensive briefing may enhance the transfer of HF aspects more than classical ACRM.

The magnetic properties of $^{\\rm 177}$Hf and $^{\\rm 180}$Hf in the strong coupling deformed model

OpenAIRE

Muto, S.; Stone, N. J.; Bingham, C. R.; Stone, J. R.; Walker, P. M.; Audi, G.; Gaulard, C.; Köster, U.; Nikolov, J.; Nishimura, K.; Ohtsubo, T.; Podolyak, Z.; Risegari, L.; Simpson, G. S.; Veskovic, M.

2014-01-01

This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2$^-$, 51.4 m, 2740 keV state in $^{\\rm 177}$Hf and the 8$^-$, 5.5 h, 1142 keV state in $^{\\rm 180}$Hf by the method of on-line nuclear orientation. Also included are results on the angular distributions of gamma transitions in the decay of the $^{\\rm 177}$Hf isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2$^+$, 1.1 s, isomer at 1315 keV ...

Human factors in training

International Nuclear Information System (INIS)

Dutton, J.W.; Brown, W.R.

1981-01-01

The Human Factors concept is a focused effort directed at those activities which require human involvement. Training is, by its nature, an activity totally dependent on the Human Factor. This paper identifies several concerns significant to training situations and discusses how Human Factor awareness can increase the quality of learning. Psychology in the training arena is applied Human Factors. Training is a method of communication represented by sender, medium, and receiver. Two-thirds of this communications model involves the human element directly

Hf isotope evidence for a hidden mantle reservoir

DEFF Research Database (Denmark)

Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.

2002-01-01

High-precision Hf isotopic analyses and U-Pb ages of carbonatites and kimberlites from Greenland and eastern North America, including Earth's oldest known carbonatite (3 Ga), indicate derivation from an enriched mantle source. This previously unidentified mantle reservoir-marked by an unradiogenic...... Hf isotopic composition and preserved in the deep mantle for at least 3 b.y.-may account for the mass imbalance in Earth's Hf-Nd budget. The Hf isotopic data presented here support a common mantle source region and genetic link between carbonatite and some oceanic-island basalt volcanoes....

Friction and Wear of Unlubricated NiTiHf with Nitriding Surface Treatments

Science.gov (United States)

Stanford, Malcolm K.

2018-01-01

The unlubricated friction and wear properties of the superelastic materials NiTi and NiTiHf, treated by either gas nitriding or plasma nitriding, have been investigated. Pin on disk testing of the studied materials was performed at sliding speeds from 0.01 to 1m/s at normal loads of 1, 5 or 10N. For all of the studied friction pairs (NiTiHf pins vs. NiTi and NiTiHf disks) over the given parameters, the steady-state coefficients of friction varied from 0.22 to 1.6. Pin wear factors ranged from approximately 1E-6 against the NiTiHf and plasma nitrided disks to approximately 1E-4 for the gas nitrided disks. The plasma nitrided disks provided wear protection in several cases and tended to wear by adhesion. The gas nitrided treatment generated the most pin wear but had essentially no disk wear except at the most severe of the studied conditions (1N load and 1m/s sliding speed). The results of this study are expected to provide guidance for design of components such as gears and fasteners.

Magnetic properties of Hf177 and Hf180 in the strong-coupling deformed model

Science.gov (United States)

Muto, S.; Stone, N. J.; Bingham, C. R.; Stone, J. R.; Walker, P. M.; Audi, G.; Gaulard, C.; Köster, U.; Nikolov, J.; Nishimura, K.; Ohtsubo, T.; Podolyak, Z.; Risegari, L.; Simpson, G. S.; Veskovic, M.; Walters, W. B.

2014-04-01

This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2-, 51.4 m, 2740 keV state in Hf177 and the 8-, 5.5 h, 1142 keV state in Hf180 by the method of on-line nuclear orientation. Also included are results on the angular distributions of γ transitions in the decay of the Hf177 isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2+, 1.1 s, isomer at 1315 keV and on the 9/2+, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the gR parameter upon the quasiproton and quasineutron make up of high-K isomeric states in this region.

Criticality accident in uranium fuel processing plant. Cause analysis and teachings from a viewpoint of a human factor

International Nuclear Information System (INIS)

Furuta, Kazuo

2000-01-01

On the JCO criticality accident occurred on September 30, 1999, from relatively earlier time since its occurrence it was elucidated that it was formed not by accident and error operation of apparatus and instruments but by unsafe actions of operators beyond regular manual as its direct cause, and that an organizational factor on business managers and safety administration unable to control such unsafe actions of operators at its background. Then, it was judged to be essential to carry out an accident research from a viewpoint of the human factor (HF) for elucidation on essence of the accident, to establish a 'special workshop on the JCO accident research' to investigate elucidation of the accident cause and countermeasure of reoccurrence at a standpoint of HF. As a result, the essential cause of this accident was summarized that safety information such as ideals, information, teachings and so forth necessary for safety management were failed to share among different organizations. As a teaching of this accident, nuclear energy participants must recognize that safety culture is not finished only in specific organization and range but produced by protecting weathering of danger consciousness and effort of mutually exciting and learning by sharing a safety information beyond different organization, range and time. (G.K.)

Oxidation behavior of Hf-modified platinum aluminide coatings during thermal cycling

Directory of Open Access Journals (Sweden)

Liya Ye

2018-02-01

Full Text Available Platinum aluminide coatings with different Hf contents were fabricated by using HfCl4. The oxidation kinetics and the rumpling behavior of oxide scale were investigated. After thermal cycling, the coating with 0.46 wt% Hf showed least weight gain. With the increase of Hf content, rumpling extent of the scale decreased. Meanwhile, HfO2 preferentially formed in the scale resulting in the increase of scale thickness. The oxidation of excessive Hf even caused the spallation of the scale. The results in the present study indicate that although Hf plays an important role in decreasing rumpling extent of TGO, the oxidation of Hf decreases the adhesion of the scale. Keywords: Pt-Al coating, Hf, Oxidation, Rumpling

Effects of HfB2 and HfN Additions on the Microstructures and Mechanical Properties of TiB2-Based Ceramic Tool Materials

Science.gov (United States)

An, Jing; Song, Jinpeng; Liang, Guoxing; Gao, Jiaojiao; Xie, Juncai; Cao, Lei; Wang, Shiying; Lv, Ming

2017-01-01

The effects of HfB2 and HfN additions on the microstructures and mechanical properties of TiB2-based ceramic tool materials were investigated. The results showed that the HfB2 additive not only can inhibit the TiB2 grain growth but can also change the morphology of some TiB2 grains from bigger polygons to smaller polygons or longer ovals that are advantageous for forming a relatively fine microstructure, and that the HfN additive had a tendency toward agglomeration. The improvement of flexural strength and Vickers hardness of the TiB2-HfB2 ceramics was due to the relatively fine microstructure; the decrease of fracture toughness was ascribed to the formation of a weaker grain boundary strength due to the brittle rim phase and the poor wettability between HfB2 and Ni. The decrease of the flexural strength and Vickers hardness of the TiB2-HfN ceramics was due to the increase of defects such as TiB2 coarse grains and HfN agglomeration; the enhancement of fracture toughness was mainly attributed to the decrease of the pore number and the increase of the rim phase and TiB2 coarse grains. The toughening mechanisms of TiB2-HfB2 ceramics mainly included crack bridging and transgranular fracture, while the toughening mechanisms of TiB2-HfN ceramics mainly included crack deflection, crack bridging, transgranular fracture, and the core-rim structure. PMID:28772821

Effects of HfB2 and HfN Additions on the Microstructures and Mechanical Properties of TiB2-Based Ceramic Tool Materials

Directory of Open Access Journals (Sweden)

Jing An

2017-04-01

Full Text Available The effects of HfB2 and HfN additions on the microstructures and mechanical properties of TiB2-based ceramic tool materials were investigated. The results showed that the HfB2 additive not only can inhibit the TiB2 grain growth but can also change the morphology of some TiB2 grains from bigger polygons to smaller polygons or longer ovals that are advantageous for forming a relatively fine microstructure, and that the HfN additive had a tendency toward agglomeration. The improvement of flexural strength and Vickers hardness of the TiB2-HfB2 ceramics was due to the relatively fine microstructure; the decrease of fracture toughness was ascribed to the formation of a weaker grain boundary strength due to the brittle rim phase and the poor wettability between HfB2 and Ni. The decrease of the flexural strength and Vickers hardness of the TiB2-HfN ceramics was due to the increase of defects such as TiB2 coarse grains and HfN agglomeration; the enhancement of fracture toughness was mainly attributed to the decrease of the pore number and the increase of the rim phase and TiB2 coarse grains. The toughening mechanisms of TiB2-HfB2 ceramics mainly included crack bridging and transgranular fracture, while the toughening mechanisms of TiB2-HfN ceramics mainly included crack deflection, crack bridging, transgranular fracture, and the core-rim structure.

The magnetic hyperfine field in the 181Ta site in the Co2HfAl and Co2HfGa Heusler alloys

International Nuclear Information System (INIS)

Silva, R. da.

1979-01-01

The hyperfine magnetic fields at 181 Ta nuclei in Heusler alloys Co 2 HfZ (Z=Al, Ga) have been measured using the time differential perturbed gamma-gamma angular correlation (TDPAC) method. The hyperfine fields obtained from these measurements at the liquid nitrogen temperature are -189 and +- 150 kOersted for Co 2 HfAl and Co 2 HfGa, respectively. The concept that the hyperfine field at the Y site is similar to the solute fields in Fe, Co, Ni and Gd matrices is corroborated. We have verified that ratios H sub(hf) sub(Ta)/T sub(c) and H sub(hf) sub(Ta)μ sub(Co) in Co 2 HfZ compounds (Z=Al, Ga, Sn) do not depend on the nature of Z element. However a dependence in the value of observed field with the s-p element in Z site was noticed. We feel that the samples are not completely ordered cubic as observed by the quadrupole interaction measurements. The results are interpreted in terms of the Campbell-Blandin formalism, and it is shown that the spin polarization of conduction electrons at Hf and Ta have opposite signs. (Author) [pt

Um estudo teórico de propriedades moleculares em complexos de hidrogênio trimoleculares C2H4···2HF, C2H2···2HF e C3h6···2HF A theoretical study of molecular properties of C2H4···2HF, C2H2···2HF AND C3H6···2HF trimolecular hydrogen-bonded complexes

Directory of Open Access Journals (Sweden)

Boaz G. Oliveira

2008-01-01

Full Text Available We present a theoretical study of molecular properties in C2H4···2HF, C2H2···2HF and C3H6···2HF trimolecular hydrogen-bonded complexes. From B3LYP/6-311++G(d,p calculations, the most important structural deformations are related to the C=C (C2H4, C≡C (C2H2, C-C (C3H6 and HF bond lengths. According to the Bader's atoms in molecules and CHELPG calculations, it was identified a tertiary interaction between the fluorine atom of the second hydrofluoric acid molecule and hydrogen atoms of the ethylene and acetylene within the C2H4···2HF and C2H2···2HF complexes, respectively. Additionally, the evaluation of the infrared spectrum characterized the new vibrational modes and bathochromic effect of the HF molecules.

Thermal evolution of CaO-doped HfO{sub 2} films and powders

Energy Technology Data Exchange (ETDEWEB)

Barolin, S A; Sanctis, O A de [Lab. Materiales Ceramicos, FCEIyA, Universidad Nacional de Rosario, IFIR-CONICET (Argentina); Caracoche, M C; Martinez, J A; Taylor, M A; Pasquevich, A F [Departamento de Fisica, FCE, Universidad Nacional de La Plata, IFLP-CONICET (Argentina); Rivas, P C, E-mail: oski@fceia.unr.edu.a [Facultad de Ciencias Agronomicas y Forestales, Universidad Nacional de La Plata, IFLP (Argentina)

2009-05-01

Solid solutions of ZrO2 and HfO2 are potential electrolyte materials for intermediate-temperature SOFC because both are oxygen-ion conductors. The main challenge for these compounds is to reduce the relatively high value of the activation energies vacancies diffusion, which is influenced by several factors. In this work the thermal evolution of CaO-HfO{sub 2} materials have been investigated. (CaO)y-Hf(1-y)O(2-y) (y = 0.06, 0.14 y 0.2) coatings and powders were synthesized by chemical solution deposition (CSD). Films were deposited onto alumina substrates by Dip Coating technique, the burning of organic waste was carried out at 500 deg. C under normal atmosphere and then the films were thermally treated at intervals of temperature rising to a maximum temperature of 1250 deg. C. By means Glazing Incidence X-ray Diffraction (rho-2theta configuration) the phases were studied in the annealed films. On the other hand, the thermal evolution and crystallization process of powders were analyzed in-situ by HT-XRD. The phenomena crystallization occurred in films and powders were analyzed. The activation energies of diffusion of oxygen vacancies of HfO2-14 mole% CaO and HfO2-20 mole% CaO films were measured from the thermal evolution of the relaxation constant measured by Perturbed Angular Correlation Technique.

Balancing human and technical reliability in the design of advanced nuclear reactors

International Nuclear Information System (INIS)

Papin, Bernard

2011-01-01

Highlights: ► Human factors exigencies are often overseen during the early design phases of NPP. ► Optimization of reactors safety is only based on technical reliability considerations. ► The search for more technical reliability often leads to more system complexity. ► System complexity is a major contributor to the operator's poor performance. ► Our method enables to assess plant complexity and it's impact on human performance. - Abstract: The strong influence of human factors (HF) on the safety of nuclear facilities is nowadays recognised and the designers are now enforced to consider HF requirements in the design of new facilities. Yet, this consideration of human factors requirements is still more or less restricted to the latest phases of the projects, essentially for the design of human-system interfaces (HSI's) and control rooms, although the design options influencing at most the human performance in operation are indeed fixed during the very early phases of the new reactors projects. The main reason of this late consideration of HF is that there exist few methods and models for anticipating the influence of fundamental design options on the future performance of operation teams. This paper describes a set of new tools permitting (i) determination of the impact of the fundamental process design options on the future activity of the operation teams and (ii) assessment of the influence of these operational constraints on teams performance. These tools are intended to guide the design of future 4th generation (GEN4) reactors, within the frame of a global risk-informed design approach, considering technical and human reliability exigencies in a balanced way.

Collision-Induced Dissociation Study of Strong Hydrogen-Bonded Cluster Ions Y-(HF) n (Y=F, O2) Using Atmospheric Pressure Corona Discharge Ionization Mass Spectrometry Combined with a HF Generator.

Science.gov (United States)

Sakamoto, Kenya; Sekimoto, Kanako; Takayama, Mitsuo

2017-01-01

Hydrogen fluoride (HF) was produced by a homemade HF generator in order to investigate the properties of strong hydrogen-bonded clusters such as (HF) n . The HF molecules were ionized in the form of complex ions associated with the negative core ions Y - produced by atmospheric pressure corona discharge ionization (APCDI). The use of APCDI in combination with the homemade HF generator led to the formation of negative-ion HF clusters Y - (HF) n (Y=F, O 2 ), where larger clusters with n ≥4 were not detected. The mechanisms for the formation of the HF, F - (HF) n , and O 2 - (HF) n species were discussed from the standpoints of the HF generator and APCDI MS. By performing energy-resolved collision-induced dissociation (CID) experiments on the cluster ions F - (HF) n ( n =1-3), the energies for the loss of HF from F - (HF) 3 , F - (HF) 2 , and F - (HF) were evaluated to be 1 eV or lower, 1 eV or higher, and 2 eV, respectively, on the basis of their center-of-mass energy ( E CM ). These E CM values were consistent with the values of 0.995, 1.308, and 2.048 eV, respectively, obtained by ab initio calculations. The stability of [O 2 (HF) n ] - ( n =1-4) was discussed on the basis of the bond lengths of O 2 H-F - (HF) n and O 2 - H-F(HF) n obtained by ab initio calculations. The calculations indicated that [O 2 (HF) 4 ] - separated into O 2 H and F - (HF) 3 .

Investigation of new type Cu-Hf-Al bulk glassy alloys

International Nuclear Information System (INIS)

Nagy, E; Ronto, V; Solyom, J; Roosz, A

2009-01-01

In the last years new type Cu-Hf-Al ternary alloys were developed with high glass forming ability and ductility. The addition of Al to Cu-Hf alloys results in improvements in glass formation, thermal stability and mechanical properties of these alloys. We have investigated new Cu-based bulk amorphous alloys in Cu-Hf-Al ternary system. The alloys with Cu 49 Hf 42 Al 9 , Cu 46 Hf 45 Al 9 , Cu 50 Hf 42.5 Al 7.5 and Cu 50 Hf 45 Al 5 compositions were prepared by arc melting. The samples were made by centrifugal casting and were investigated by X-ray diffraction method. Thermodynamic properties were examined by differential scanning calorimetry and the structure of the crystallising phases by scanning electron microscopy. The determination of liquidus temperatures of alloys were measured by differential thermal analysis.

Enhanced resistive switching and multilevel behavior in bilayered HfAlO/HfAlO{sub x} structures for non-volatile memory applications

Energy Technology Data Exchange (ETDEWEB)

Faita, F. L., E-mail: fabriciofaita@gmail.com [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Departamento de Física, Universidade Federal de Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC (Brazil); Silva, J. P. B., E-mail: josesilva@fisica.uminho.pt [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto (Portugal); Pereira, M.; Gomes, M. J. M. [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

2015-12-14

In this work, hafnium aluminum oxide (HfAlO) thin films were deposited by ion beam sputtering deposition technique on Si substrate. The presence of oxygen vacancies in the HfAlO{sub x} layer deposited in oxygen deficient environment is evidenced from the photoluminescence spectra. Furthermore, HfAlO(oxygen rich)/HfAlO{sub x}(oxygen poor) bilayer structures exhibit multilevel resistive switching (RS), and the switching ratio becomes more prominent with increasing the HfAlO layer thickness. The bilayer structure with HfAlO/HfAlO{sub x} thickness of 30/40 nm displays the enhanced multilevel resistive switching characteristics, where the high resistance state/intermediate resistance state (IRS) and IRS/low resistance state resistance ratios are ≈10{sup 2} and ≈5 × 10{sup 5}, respectively. The switching mechanisms in the bilayer structures were investigated by the temperature dependence of the three resistance states. This study revealed that the multilevel RS is attributed to the coupling of ionic conduction and the metallic conduction, being the first associated to the formation and rupture of conductive filaments related to oxygen vacancies and the second with the formation of a metallic filament. Moreover, the bilayer structures exhibit good endurance and stability in time.

Thermodynamics of HfCl/sub 4/-KCl molten mixtures containing HfCl/sub 4/ up to 33. 3 mol. per cent

Energy Technology Data Exchange (ETDEWEB)

Smirnov, M V; Salyulev, A B; Kudyakov, V Ya [AN SSSR, Sverdlovsk. Inst. Ehlektrokhimii

1980-05-01

Based on measurements of saturated vapour pressure in components of melted mixtures of HfCl/sub 4/-KCl, depending on temperature and concentration, calculated are the results of changes in activity coefficients of hafnium tetrachloride and potassium chloride on transition from diluted solutions, where the Henry law is met, to those concentrated where the law is disobeyed. Growth in the activity coefficient of HfCl/sub 4/ is due to dissociation of complex groups of HfCl/sub 6//sup 2 -/ into complexes with a lesser number of ligands and decreasing relative binding energy of Hf/sup 4 +/-Cl/sup -/ there. In this case, marked changes take place in partial enthalpy and entropy of hafnium tetrachloride mixing. Similar dependences are observed for potassium chloride, but they are expressed considerably weaker. Evaporation enthalpy and entropy are calculated for HfCl/sub 4/ and KCl monomers from their melted mixtures of various concentrations.

In-situ atomic layer deposition growth of Hf-oxide

International Nuclear Information System (INIS)

Karavaev, Konstantin

2010-01-01

We have grown HfO 2 on Si(001) by atomic layer deposition (ALD) using HfCl 4 , TEMAHf, TDMAHf and H 2 O as precursors. The early stages of the ALD were investigated with high-resolution photoelectron spectroscopy and X-ray absorption spectroscopy. We observed the changes occurring in the Si 2p, O 1s, Hf 4f, Hf 4d, and Cl 2p (for HfCl 4 experiment) core level lines after each ALD cycle up to the complete formation of two layers of HfO 2 . The investigation was carried out in situ giving the possibility to determine the properties of the grown film after every ALD cycle or even after a half cycle. This work focused on the advantages in-situ approach in comparison with ex-situ experiments. The study provides to follow the evolution of the important properties of HfO 2 : contamination level, density and stoichiometry, and influence of the experimental parameters to the interface layer formation during ALD. Our investigation shows that in-situ XPS approach for ALD gives much more information than ex-situ experiments. (orig.)

In-situ atomic layer deposition growth of Hf-oxide

Energy Technology Data Exchange (ETDEWEB)

Karavaev, Konstantin

2010-06-17

We have grown HfO{sub 2} on Si(001) by atomic layer deposition (ALD) using HfCl{sub 4}, TEMAHf, TDMAHf and H{sub 2}O as precursors. The early stages of the ALD were investigated with high-resolution photoelectron spectroscopy and X-ray absorption spectroscopy. We observed the changes occurring in the Si 2p, O 1s, Hf 4f, Hf 4d, and Cl 2p (for HfCl{sub 4} experiment) core level lines after each ALD cycle up to the complete formation of two layers of HfO{sub 2}. The investigation was carried out in situ giving the possibility to determine the properties of the grown film after every ALD cycle or even after a half cycle. This work focused on the advantages in-situ approach in comparison with ex-situ experiments. The study provides to follow the evolution of the important properties of HfO{sub 2}: contamination level, density and stoichiometry, and influence of the experimental parameters to the interface layer formation during ALD. Our investigation shows that in-situ XPS approach for ALD gives much more information than ex-situ experiments. (orig.)

Creation of an in vitro microenvironment to enhance human fetal synovium-derived stem cell chondrogenesis.

Science.gov (United States)

Li, Jingting; He, Fan; Pei, Ming

2011-09-01

Our aim was to assess the feasibility of the sequential application of extracellular matrix (ECM) and low oxygen to enhance chondrogenesis in human fetal synovium-derived stem cells (hfSDSCs). Human fetal synovial fibroblasts (hfSFs) were characterized and found to include hfSDSCs, as evidenced by their multi-differentiation capacity and the surface phenotype markers typical of mesenchymal stem cells. Passage-7 hfSFs were plated on either conventional plastic flasks (P) or ECM deposited by hfSFs (E) for one passage. Passage-8 hfSFs were then reseeded for an additional passage on either P or E. The pellets from expanded hfSFs were incubated in a serum-free chondrogenic medium supplemented with 10 ng/ml transforming growth factor-β3 under either normoxia (21% O(2); 21) or hypoxia (5% O(2); 5) for 14 days. Pellets were collected for evaluation of the treatments (EE21, EE5, EP21, EP5, PE21, PE5, PP21, and PP5) on expanded hfSF chondrogenesis by using histology, immunostaining, biochemistry, and real-time polymerase chain reaction. Our data suggest that, compared with seeding on conventional plastic flasks, hfSFs expanded on ECM exhibit a lower expression of senescence-associated β-galactosidase and an enhanced level of stage-specific embryonic antigen-4. ECM-expanded hfSFs also show increased cell numbers and an enhanced chondrogenic potential. Low oxygen (5% O(2)) during pellet culture enhances hfSF chondrogenesis. Thus, we demonstrate, for the first time, the presence of stem cells in hfSFs, and that modulation of the in vitro microenvironment can enhance hfSDSC chondrogenesis. hfSDSCs might represent a promising cell source for cartilage tissue engineering and regeneration.

The human factors engineering approach to biomedical informatics projects: state of the art, results, benefits and challenges.

Science.gov (United States)

Beuscart-Zéphir, M-C; Elkin, Peter; Pelayo, Sylvia; Beuscart, Regis

2007-01-01

The objective of this paper is to define a comprehensible overview of the Human Factors approach to biomedical informatics applications for healthcare. The overview starts with a presentation of the necessity of a proper management of Human factors for Healthcare IT projects to avoid unusable products and unsafe work situations. The first section is dedicated to definitions of the Human Factors Engineering (HFE) main concepts. The second section describes a functional model of an HFE lifecycle adapted for healthcare work situations. The third section provides an overview of existing HF and usability methods for healthcare products and presents a selection of interesting results. The last section discusses the benefits and limitations of the HFE approach. Literature review based on Pubmed and conference proceedings in the field of Medical Informatics coupled with a review of other databases and conference proceedings in the field of Ergonomics focused on papers addressing healthcare work and system design. Usability studies performed on healthcare applications have uncovered unacceptable usability flaws that make the systems error prone, thus endangering the patient safety. Moreover, in many cases, the procurement and the implementation process simply forget about human factors: following only technological considerations, they issue potentially dangerous and always unpleasant work situations. But when properly applied to IT projects, the HFE approach proves efficient when seeking to improve patient safety, users' satisfaction and adoption of the products. We recommend that the HFE methodology should be applied to most informatics and systems development projects, and the usability of the products should be systematically checked before permitting their release and implementation. This requires the development of Centers specialized in Human Factors for Healthcare and Patient safety in each Country/Region.

HF-START: A Regional Radio Propagation Simulator

Science.gov (United States)

Hozumi, K.; Maruyama, T.; Saito, S.; Nakata, H.; Rougerie, S.; Yokoyama, T.; Jin, H.; Tsugawa, T.; Ishii, M.

2017-12-01

HF-START (HF Simulator Targeting for All-users' Regional Telecommunications) is a user-friendly simulator developed to meet the needs of space weather users. Prediction of communications failure due to space weather disturbances is of high priority. Space weather users from various backgrounds with high economic impact, i.e. airlines, telecommunication companies, GPS-related companies, insurance companies, international amateur radio union, etc., recently increase. Space weather information provided by Space Weather Information Center of NICT is, however, too professional to be understood and effectively used by the users. To overcome this issue, I try to translate the research level data to the user level data based on users' needs and provide an immediate usable data. HF-START is positioned to be a space weather product out of laboratory based truly on users' needs. It is originally for radio waves in HF band (3-30 MHz) but higher frequencies up to L band are planned to be covered. Regional ionospheric data in Japan and southeast Asia are employed as a reflector of skywave mode propagation. GAIA (Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy) model will be used as ionospheric input for global simulation. To evaluate HF-START, an evaluation campaign for Japan region will be launched in coming months. If the campaign successes, it will be expanded to southeast Asia region as well. The final goal of HF-START is to provide the near-realtime necessary radio parameters as well as the warning message of radio communications failure to the radio and space weather users.

Ferromagnetic characteristics of HfFe2

International Nuclear Information System (INIS)

Novakovic, N.; Belosevic-Cavor, J.; Cekic, B.; Manasijevic, M.; Milosevic, Z. . E-mail address of correspoding author: novnik@rt270.vin.bg.ac.yu; Novakovic, N.)

2003-01-01

The magnetic hyperfine fields at 181 Ta ion-probe sites in the HfFe 2 polycrystalline binary compound were measured using the time-differential perturbed angular correlation (TDPAC) method. Measurements were performed in the absence of polarizing external magnetic field, at room temperature. The existence of two different structures, dominant cubic MgCu 2 -type and hexagonal MgZn 2 -type in our HfFe 2 sample was refined. Both structures are ferromagnetic with Curie temperatures, which differ significantly (588 K for MgCu 2 and 427 K for MgZn 2 ). The corresponding values of hyperfine fields are H hf 13.8±0.1 T for MgCu 2 -type structure and H hf = 8.0±0.2 T for MgZn 2 -type structure. Calculations using LAPW-Wien 97 program package are in progress and preliminary results are in good agreement with experiment. The analysis includes qualitative explanation of the exchange interactions mechanism between magnetic dipole moment of the observed 181 Ta ion-probe and magnetic dipole moments of the nearest neighbours on the corresponding coordination polyhedra. All these results will be published recently. (author)

Human factor reliability program

International Nuclear Information System (INIS)

Knoblochova, L.

2017-01-01

The human factor's reliability program was at Slovenske elektrarne, a.s. (SE) nuclear power plants. introduced as one of the components Initiatives of Excellent Performance in 2011. The initiative's goal was to increase the reliability of both people and facilities, in response to 3 major areas of improvement - Need for improvement of the results, Troubleshooting support, Supporting the achievement of the company's goals. The human agent's reliability program is in practice included: - Tools to prevent human error; - Managerial observation and coaching; - Human factor analysis; -Quick information about the event with a human agent; -Human reliability timeline and performance indicators; - Basic, periodic and extraordinary training in human factor reliability(authors)

Nanosized Hydroxyapatite Precipitation on the Ti—30Ta—xHf Alloys.

Science.gov (United States)

Lee, Kang; Jang, Jae- In; Han-Cheol, Choe

2017-04-01

In this study, we prepared hydroxyapatite (HAp) layer on the alkali treated Ti–30Ta–xHf alloys using electrochemical deposition method. Ti–30Ta–xHf alloys was anodized in 5 M NaOH solution at 0.3 A for 10 min. Alkali treated Ti–30Ta–xHf surface formed by anodization step which acted as templates and anchorage for growth of the HAp during subsequent pulsed electrochemical deposition process at 85 °C. The phase and morphologies of deposited HAp layer were affected by the Hf contents of Ti–30Ta–xHf alloys. The nano-scale rod-like HAp layer was formed on untreated Ti–30Ta–xHf alloys with partially low crystallinity. In the case of alkali treated Ti–30Ta–xHf, nano-sized needle-like layers were transferred to nano-flake surface and denser morphology as Hf content increased.

Critical human-factors issues in nuclear-power regulation and a recommended comprehensive human-factors long-range plan. Critical discussion of human factors areas of concern

International Nuclear Information System (INIS)

Hopkins, C.O.; Snyder, H.L.; Price, H.E.; Hornick, R.J.; Mackie, R.R.; Smillie, R.J.; Sugarman, R.C.

1982-08-01

This comprehensive long-range human factors plan for nuclear reactor regulation was developed by a Study Group of the Human Factors Society, Inc. This Study Group was selected by the Executive Council of the Society to provide a balanced, experienced human factors perspective to the applications of human factors scientific and engineering knowledge to nuclear power generation. The report is presented in three volumes. Volume 1 contains an Executive Summary of the 18-month effort and its conclusions. Volume 2 summarizes all known nuclear-related human factors activities, evaluates these activities wherever adequate information is available, and describes the recommended long-range (10-year) plan for human factors in regulation. Volume 3 elaborates upon each of the human factors issues and areas of recommended human factors involvement contained in the plan, and discusses the logic that led to the recommendations

HF-voltage testing of accelerating system functional model

International Nuclear Information System (INIS)

Gladkov, A.V.; Stepanov, V.B.

1989-01-01

Owing to ambiguity in interpreting the notion of the electron strength of the operating HF device in an acceleator a technique of measurements and result processing, based on statistical analysis of the data is suggested. Experimental testing on electric strength of structures with HF focusing was carried out using a bench in the form of a cylindrical vacuum container inside which a double H-resonator with HF quadrupole electrodes without surface modulation was installed. The dependences obtained permit to evaluate the bahaviour of the HF device from the viewpoint of electric strength and radiation hazard for the whole range of possible values of voltage on the basis of data on the frequency of breakdowns and radiation situation only in one experimental point. 12 refs.; 8 figs

The isobutylene-isobutane alkylation process in liquid HF revisited.

Science.gov (United States)

Esteves, P M; Araújo, C L; Horta, B A C; Alvarez, L J; Zicovich-Wilson, C M; Ramírez-Solís, A

2005-07-07

Details on the mechanism of HF catalyzed isobutylene-isobutane alkylation were investigated. On the basis of available experimental data and high-level quantum chemical calculations, a detailed reaction mechanism is proposed taking into account solvation effects of the medium. On the basis of our computational results, we explain why the density of the liquid media and stirring rates are the most important parameters to achieve maximum yield of alkylate, in agreement with experimental findings. The ab initio Car-Parrinello molecular dynamics calculations show that isobutylene is irreversibly protonated in the liquid HF medium at higher densities, leading to the ion pair formation, which is shown to be a minimum on the potential energy surface after optimization using periodic boundary conditions. The HF medium solvates preferentially the fluoride anion, which is found as solvated [FHF](-) or solvated F(-.)(HF)(3). On the other hand, the tert-butyl cation is weakly solvated, where the closest HF molecules appear at a distance of about 2.9 Angstrom with the fluorine termination of an HF chain.

Sequential sputtered Co-HfO{sub 2} granular films

Energy Technology Data Exchange (ETDEWEB)

Chadha, M.; Ng, V.

2017-03-15

A systematic study of magnetic, magneto-transport and micro-structural properties of Co-HfO{sub 2} granular films fabricated by sequential sputtering is presented. We demonstrate reduction in ferromagnetic-oxide formation by using HfO{sub 2} as the insulting matrix. Microstructure evaluation of the films showed that the film structure consisted of discrete hcp-Co grains embedded in HfO{sub 2} matrix. Films with varying compositions were prepared and their macroscopic properties were studied. We correlate the variation in these properties to the variation in film microstructure. Our study shows that Co-HfO{sub 2} films with reduced cobalt oxide and varying properties can be prepared using sequential sputtering technique. - Highlights: • Co-HfO{sub 2} granular films were prepared using sequential sputtering. • A reduction in ferromagnetic-oxide formation is observed. • Co-HfO{sub 2} films display superparamagnetism and tunnelling magneto-resistance. • Varying macroscopic properties were achieved by changing film composition. • Applications can be found in moderate MR sensors and high –frequency RF devices.

HF Interference, Procedures and Tools (Interferences HF, procedures et outils)

Science.gov (United States)

2007-06-01

the actual ambient noise floor situation. Besides these HF radio links, special units such as crisis reaction forces are using low power radios for...the origin point on the ground. For ease of arithmetic and typography , the latter option is preferable. The dipole-modelled PLT is located at x = H1

Modelling of Phase Equlibria in the Hf-V System\

Czech Academy of Sciences Publication Activity Database

Vřešťál, Jan; Pavlů, Jana; Wdowik, U. D.; Šob, Mojmír

2017-01-01

Roč. 53, č. 3 (2017), s. 239-247 ISSN 1450-5339 R&D Projects: GA ČR GA14-15576S; GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Laves phases * Hf-V system * Ab initio calculations * Phase diagram * Zero Kelvin * CALPHAD method Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.804, year: 2016

Search for chemical separations of the element 106 homologues in HF and HF-HCl media

International Nuclear Information System (INIS)

Trubert, D.; Monroy-Guzman, F.; Hussonnois, M.; Brillard, L.; Le Naour, C.; Constantinescu, O.

1996-01-01

In order to study the chemical properties of element 263 106 in aqueous media, fast, efficient and reproducible chromatographic separations were tested on its assumed homologous: Mo, W and U. Corroborative static and dynamic off-line experiments have shown that after fixation of these three elements on anion-exchange resin in HF medium, selective elution could be achieved by using suitable concentration of HCl - HF and HCl solutions. Separations of short-lived W isotopes, produced through heavy ion irradiation were also performed on-line. (author). 27 refs., 14 figs

HF band filter bank multi-carrier spread spectrum

Energy Technology Data Exchange (ETDEWEB)

Laraway, Stephen Andrew; Moradi, Hussein; Farhang-Boroujeny, Behrouz

2015-10-01

Abstract—This paper describes modifications to the filter bank multicarrier spread spectrum (FB-MC-SS) system, that was presented in [1] and [2], to enable transmission of this waveform in the HF skywave channel. FB-MC-SS is well suited for the HF channel because it performs well in channels with frequency selective fading and interference. This paper describes new algorithms for packet detection, timing recovery and equalization that are suitable for the HF channel. Also, an algorithm for optimizing the peak to average power ratio (PAPR) of the FBMC- SS waveform is presented. Application of this algorithm results in a waveform with low PAPR. Simulation results using a wide band HF channel model demonstrate the robustness of this system over a wide range of delay and Doppler spreads.

SnO2 anode surface passivation by atomic layer deposited HfO2 improves li-ion battery performance

KAUST Repository

Yesibolati, Nulati

2014-03-14

For the first time, it is demonstrated that nanoscale HfO2 surface passivation layers formed by atomic layer deposition (ALD) significantly improve the performance of Li ion batteries with SnO2-based anodes. Specifically, the measured battery capacity at a current density of 150 mAg -1 after 100 cycles is 548 and 853 mAhg-1 for the uncoated and HfO2-coated anodes, respectively. Material analysis reveals that the HfO2 layers are amorphous in nature and conformably coat the SnO2-based anodes. In addition, the analysis reveals that ALD HfO2 not only protects the SnO2-based anodes from irreversible reactions with the electrolyte and buffers its volume change, but also chemically interacts with the SnO2 anodes to increase battery capacity, despite the fact that HfO2 is itself electrochemically inactive. The amorphous nature of HfO2 is an important factor in explaining its behavior, as it still allows sufficient Li diffusion for an efficient anode lithiation/delithiation process to occur, leading to higher battery capacity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nuclear quadrupole interactions in ferroelectric compounds of HF181

International Nuclear Information System (INIS)

Kunzler, J.V.

1971-01-01

Measurements of nuclear quadrupole interaction constants in perovkite-type compounds of PbHfO 3 , SnhfO 3 , CaHfO 3 e SrHfO 3 have been performed using the perturbed angular correlation technique. A range of fundamental frequencies from 150 to 550 Megaradians persecond was determined. The variation of quadrupole constants has been discussed through the molecular orbital theory

Thermoluminescence in films of HfO2:Dy+3

International Nuclear Information System (INIS)

Ceron, P.; Rivera, T.; Guzman, J.; Montes, E.; Pelaez, A.; Rojas, B.; Guzman, D.; Azorin, J.; Paredes, L.

2014-08-01

In this work the thermoluminescence (TL) response of films of hafnium oxide polluted with dysprosium (HfO 2 :Dy +3 ) that were irradiated in the near UV (200 nm - 400 nm). The films were deposited by means of the ultrasonics spray pyrolysis technique on a glass substrate, using different deposit temperatures (300 grades C - 600 grades C). The best TL emission corresponded to the prepared film to 450 grades C that was exposed to a spectral irradiation of 80 μJ/(cm 2 -s) with a wave longitude of 240 nm. The TL response in function of the spectral irradiation was lineal in the studied interval (24 to 288 mJ/cm 2 ), several kinetic parameters were also calculated of the shine curve as depth of the trap (E), frequency factor (s) and order to the kinetics (b). The obtained results show that the films of HfO 2 :Dy +3 could be used as radiation monitor in the region of the near UV. (Author)

Lu-Hf and Sm-Nd garnet geochronology

DEFF Research Database (Denmark)

Smit, Matthijs Arjen; Scherer, Erik E.; Mezger, Klaus

2013-01-01

To investigate the systematics of the 176Lu–176Hf and 147Sm–143Nd garnet chronometers, we performed REE and isotope analyses on garnet crystals of different size (0.55–3.1 mm radius) from a single granulite specimen (Archean Pikwitonei Granulite Domain, Manitoba, Canada). The Lu–Hf dates are simi...

Human factors in network security

OpenAIRE

Jones, Francis B.

1991-01-01

Human factors, such as ethics and education, are important factors in network information security. This thesis determines which human factors have significant influence on network security. Those factors are examined in relation to current security devices and procedures. Methods are introduced to evaluate security effectiveness by incorporating the appropriate human factors into network security controls

[Human factors in medicine].

Science.gov (United States)

Lazarovici, M; Trentzsch, H; Prückner, S

2017-01-01

The concept of human factors is commonly used in the context of patient safety and medical errors, all too often ambiguously. In actual fact, the term comprises a wide range of meanings from human-machine interfaces through human performance and limitations up to the point of working process design; however, human factors prevail as a substantial cause of error in complex systems. This article presents the full range of the term human factors from the (emergency) medical perspective. Based on the so-called Swiss cheese model by Reason, we explain the different types of error, what promotes their emergence and on which level of the model error prevention can be initiated.

Solid phase crystallisation of HfO2 thin films

International Nuclear Information System (INIS)

Modreanu, M.; Sancho-Parramon, J.; O'Connell, D.; Justice, J.; Durand, O.; Servet, B.

2005-01-01

In this paper, we report on the solid phase crystallisation of carbon-free HfO 2 thin films deposited by plasma ion assisted deposition (PIAD). After deposition, the HfO 2 films were annealed in N 2 ambient for 3 h at 350, 550 and 750 deg. C. Several characterisation techniques including X-ray reflectometry (XRR), X-ray diffraction (XRD), spectroscopic ellipsometry (SE) and atomic force microscopy (AFM) were used for the physical characterisation of as-deposited and annealed HfO 2 . XRD has revealed that the as-deposited HfO 2 film is in an amorphous-like state with only traces of crystalline phase and that the annealed films are in a highly crystalline state. These results are in good agreement with the SE results showing an increase of refractive index by increasing the annealing temperature. XRR results show a significant density gradient over the as-deposited film thickness, which is characteristic of the PIAD method. The AFM measurements show that the HfO 2 layers have a smooth surface even after annealing at 750 deg. C. The present study demonstrates that the solid phase crystallisation of HfO 2 PIAD thin films starts at a temperature as low as 550 deg. C

Halofuginone suppresses growth of human uterine leiomyoma cells in a mouse xenograft model.

Science.gov (United States)

Koohestani, Faezeh; Qiang, Wenan; MacNeill, Amy L; Druschitz, Stacy A; Serna, Vanida A; Adur, Malavika; Kurita, Takeshi; Nowak, Romana A

2016-07-01

Does halofuginone (HF) inhibit the growth of human uterine leiomyoma cells in a mouse xenograft model? HF suppresses the growth of human uterine leiomyoma cells in a mouse xenograft model through inhibiting cell proliferation and inducing apoptosis. Uterine leiomyomas are the most common benign tumors of the female reproductive tract. HF can suppress the growth of human uterine leiomyoma cells in vitro. The mouse xenograft model reflects the characteristics of human leiomyomas. Primary leiomyoma smooth muscle cells from eight patients were xenografted under the renal capsule of adult, ovariectomized NOD-scid IL2Rγ(null) mice (NSG). Mice were treated with two different doses of HF or vehicle for 4 weeks with six to eight mice per group. Mouse body weight measurements and immunohistochemical analysis of body organs were carried out to assess the safety of HF treatment. Xenografted tumors were measured and analyzed for cellular and molecular changes induced by HF. Ovarian steroid hormone receptors were evaluated for possible modulation by HF. Treatment of mice carrying human UL xenografts with HF at 0.25 or 0.50 mg/kg body weight for 4 weeks resulted in a 35-40% (P leiomyoma cells in an in vivo model, HF was administered to mice whose tolerance and metabolism of the drug may differ from that in humans. Also, the longer term effects of HF treatment are yet unclear. The results of this study showing the effectiveness of HF in reducing UL tumor growth by interfering with the main cellular processes regulating cell proliferation and apoptosis are in agreement with previous studies on the effects of HF on other fibrotic diseases. HF can be considered as a candidate for reducing the size of leiomyomas, particularly prior to surgery. This project was funded by NIH PO1HD057877 and R01 HD064402. Authors report no competing interests. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights

Mechanical alloying of Hf and Fe powders

International Nuclear Information System (INIS)

Mendoza Zelis, L.; Crespo, E.; Creus, M.; Damonte, L.C.; Sanchez, F.H.; Punte, G.

1994-01-01

Pure crystalline Hf and Fe powders were mixed and milled under an argon atmosphere. The evolution of the system with milling time was followed with Moessbauer effect spectroscopy and X-ray diffraction. The results indicate that in the first stages an amorphous Fe-rich alloy was gradually formed together with a solid solution of Hf in Fe beyond the solubility limit. (orig.)

Human factors guides

International Nuclear Information System (INIS)

Penington, J.

1995-10-01

This document presents human factors guides, which have been developed in order to provide licensees of the AECB with advice as to how to address human factors issues within the design and assessment process. This documents presents the results of a three part study undertaken to develop three guides which are enclosed in this document as Parts B, C and D. As part of the study human factors standards, guidelines, handbooks and other texts were researched, to define those which would be most useful to the users of the guides and for the production of the guides themselves. Detailed specifications were then produced to outline the proposed contents and format of the three guides. (author). 100 refs., 3 tabs., 11 figs

Human factors guides

Energy Technology Data Exchange (ETDEWEB)

Penington, J [PHF Services Inc., (Canada)

1995-10-01

This document presents human factors guides, which have been developed in order to provide licensees of the AECB with advice as to how to address human factors issues within the design and assessment process. This documents presents the results of a three part study undertaken to develop three guides which are enclosed in this document as Parts B, C and D. As part of the study human factors standards, guidelines, handbooks and other texts were researched, to define those which would be most useful to the users of the guides and for the production of the guides themselves. Detailed specifications were then produced to outline the proposed contents and format of the three guides. (author). 100 refs., 3 tabs., 11 figs.

Thermoluminescence in films of HfO{sub 2}:Dy{sup +3}; Termoluminiscencia en peliculas de HfO{sub 2}:Dy{sup +3}

Energy Technology Data Exchange (ETDEWEB)

Ceron, P.; Rivera, T.; Guzman, J.; Montes, E.; Pelaez, A.; Rojas, B.; Guzman, D. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Paredes, L., E-mail: victceronr@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2014-08-15

In this work the thermoluminescence (TL) response of films of hafnium oxide polluted with dysprosium (HfO{sub 2}:Dy{sup +3}) that were irradiated in the near UV (200 nm - 400 nm). The films were deposited by means of the ultrasonics spray pyrolysis technique on a glass substrate, using different deposit temperatures (300 grades C - 600 grades C). The best TL emission corresponded to the prepared film to 450 grades C that was exposed to a spectral irradiation of 80 μJ/(cm{sup 2}-s) with a wave longitude of 240 nm. The TL response in function of the spectral irradiation was lineal in the studied interval (24 to 288 mJ/cm{sup 2}), several kinetic parameters were also calculated of the shine curve as depth of the trap (E), frequency factor (s) and order to the kinetics (b). The obtained results show that the films of HfO{sub 2}:Dy{sup +3} could be used as radiation monitor in the region of the near UV. (Author)

HF Radar observations of the Dardanelles outflow current in North Eastern Aegean using validated WERA HF radar data

Directory of Open Access Journals (Sweden)

Z. KOKKINI

2014-12-01

Full Text Available A two-site WERA HF radar station was installed in November 2009 at the eastern coast of Lemnos Island in North Aegean Sea, aiming to monitor the surface inflow of Black Sea waters exiting from the Dardanelles Strait, as well as to constitute a coastal management tool for incidents of oil-pollution or save-and-rescue operations. Strong interference by foreign transmissions is a source of noise deteriorating the quality of the backscattered signal, thus significantly reducing the HF radar’s effective data return rate. In order to ameliorate this problem, further quality-control and data gap interpolating procedures have been developed and applied, to be used in addition to the procedures incorporated and used by the manufacturer’s signal processing software. The second-level processing involves traditional despiking in the temporal domain, preceding Empirical Orthogonal Function analysis. The latter is used not only to filter high-frequency noise but also to fill data gaps in time and space. The data reconstruction procedure has been assessed via comparison of (a HF radial with CODE-type drifter radial velocities as well as (b HF-derived virtual drifter tracks with actual drifter tracks. The main circulation features and their variability, as revealed by the reconstructed fields, are presented.

HF-laser program

International Nuclear Information System (INIS)

Anon.

1978-01-01

The HF laser is an attractive candidate driver for a large-system ICF scientific demonstration facility, for an ICF experimental power reactor and for a commercial laser--fusion power reactor. Previous accomplishments of the program have included demonstrations of high efficiency and high energy capability, efficient energy extraction from HF amplifiers, good beam quality and focusability, and short-pulse generation and amplification. In the reporting period, beam quality has been determined to be near-diffraction limited for a short pulsewidth (6 ns to 25 ns) oscillator-amplifier chain, suppression of amplified spontaneous emission has been demonstrated on an individual spectral line, high-pressure characteristics have been determined for the Phoenix I amplifier, and detailed comparisions between the kinetic code and experiments have been made. Details of two major upcoming experiments are also included. The first is energy extraction and beam quality measurements on the Phoenix I amplifier operating under saturated output power conditions. The second experiment, using a newly designed amplifier (Phoenix II), is designed to demonstrate the concept of angular-multiplexing: a pulse width-compression scheme

Chemical stability and defect formation in CaHfO3

KAUST Repository

Alay-E-Abbas, Syed Muhammad

2014-04-01

Defects in CaHfO3 are investigated by ab initio calculations based on density functional theory. Pristine and anion-deficient CaHfO 3 are found to be insulating, whereas cation-deficient CaHfO 3 is hole-doped. The formation energies of neutral and charged cation and anion vacancies are evaluated to determine the stability in different chemical environments. Moreover, the energies of the partial and full Schottky defect reactions are computed. We show that clustering of anion vacancies in the HfO layers is energetically favorable for sufficiently high defect concentrations and results in metallicity. © 2014 EPLA.

Chemical stability and defect formation in CaHfO3

KAUST Repository

Alay-E-Abbas, Syed Muhammad; Nazir, Safdar; Mun Wong, Kin; Shaukat, Ali; Schwingenschlö gl, Udo

2014-01-01

Defects in CaHfO3 are investigated by ab initio calculations based on density functional theory. Pristine and anion-deficient CaHfO 3 are found to be insulating, whereas cation-deficient CaHfO 3 is hole-doped. The formation energies of neutral and charged cation and anion vacancies are evaluated to determine the stability in different chemical environments. Moreover, the energies of the partial and full Schottky defect reactions are computed. We show that clustering of anion vacancies in the HfO layers is energetically favorable for sufficiently high defect concentrations and results in metallicity. © 2014 EPLA.

Formation of the high-spin Hf-179m2 isomer in reactor irradiations

Czech Academy of Sciences Publication Activity Database

Karamian, S. A.; Carroll, J. J.; Adam, Jindřich; Kulagin, EN.; Shabalin, EP.

2004-01-01

Roč. 14, č. 4 (2004), s. 438-441 ISSN 1054-660X R&D Projects: GA MŠk(CZ) ME 134 Keywords : reactor irradiation * high-spin Hf-179m2 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.836, year: 2004

Development of Cu-Hf-Al ternary systems and tungsten wire/particle reinforced Cu48Hf43Al9 bulk metallic glass composites for strengthening

International Nuclear Information System (INIS)

Park, Joyoung; An, Jihye; Choi-Yim, Haein

2010-01-01

Stable bulk glass forming alloys can be developed over a wide range of compositions in Cu-Hf-Al ternary systems starting from the Cu 49 Hf 42 Al 9 bulk metallic glass. Ternary Cu-Hf-Al alloys can be cast directly from the melt into copper molds to form fully amorphous strips with thicknesses of 1 to 6 mm. The maximum critical diameter of the new Cu-Hf-Al ternary alloy was 6 mm. X-ray diffraction patterns were used to confirm the amorphous nature of the ternary Cu-Hf-Al alloys. To increase the toughness of these metallic glasses, we reinforced the Cu 48 Hf 43 Al 9 bulk metallic glass-forming liquid with a 50% volume fraction of tungsten particles and an 80% volume fraction of tungsten wires with diameters of 242.4 μm. Composites with a critical diameter of 7 mm and length 70 mm were synthesized. The structure of the composites was confirmed by using X-ray diffraction (XRD), and the scanning electron microscopy (SEM). The mechanical properties of the composites were studied in compression tests. The thermal stability and the crystallization processes of the Cu-Hf-Al alloys and composites were investigated by using differential scanning calorimetry (DSC). Values of the glass transition temperature (T g ), the crystallization temperature (T x ), and the supercooled liquid region (ΔT = T x - T g ) are given in this paper.

Do Hf isotopes in magmatic zircons represent those of their host rocks?

Science.gov (United States)

Wang, Di; Wang, Xiao-Lei; Cai, Yue; Goldstein, Steven L.; Yang, Tao

2018-04-01

Lu-Hf isotopic system in zircon is a powerful and widely used geochemical tracer in studying petrogenesis of magmatic rocks and crustal evolution, assuming that zircon Hf isotopes can represent initial Hf isotopes of their parental whole rock. However, this assumption may not always be valid. Disequilibrium partial melting of continental crust would preferentially melt out non-zircon minerals with high time-integrated Lu/Hf ratios and generate partial melts with Hf isotope compositions that are more radiogenic than those of its magma source. Dissolution experiments (with hotplate, bomb and sintering procedures) of zircon-bearing samples demonstrate this disequilibrium effect where partial dissolution yielded variable and more radiogenic Hf isotope compositions than fully dissolved samples. A case study from the Neoproterozoic Jiuling batholith in southern China shows that about half of the investigated samples show decoupled Hf isotopes between zircons and the bulk rocks. This decoupling could reflect complex and prolonged magmatic processes, such as crustal assimilation, magma mixing, and disequilibrium melting, which are consistent with the wide temperature spectrum from ∼630 °C to ∼900 °C by Ti-in-zircon thermometer. We suggest that magmatic zircons may only record the Hf isotopic composition of their surrounding melt during crystallization and it is uncertain whether their Hf isotopic compositions can represent the primary Hf isotopic compositions of the bulk magmas. In this regard, using zircon Hf isotopic compositions to trace crustal evolution may be biased since most of these could be originally from disequilibrium partial melts.

Surface Characterization, Corrosion Resistance and in Vitro Biocompatibility of a New Ti-Hf-Mo-Sn Alloy

Science.gov (United States)

Ion, Raluca; Drob, Silviu Iulian; Ijaz, Muhammad Farzik; Vasilescu, Cora; Osiceanu, Petre; Gordin, Doina-Margareta; Cimpean, Anisoara; Gloriant, Thierry

2016-01-01

A new superelastic Ti-23Hf-3Mo-4Sn biomedical alloy displaying a particularly large recovery strain was synthesized and characterized in this study. Its native passive film is very thick (18 nm) and contains very protective TiO2, Ti2O3, HfO2, MoO2, and SnO2 oxides (XPS analysis). This alloy revealed nobler electrochemical behavior, more favorable values of the corrosion parameters and open circuit potentials in simulated body fluid in comparison with commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy taken as reference biomaterials in this study. This is due to the favorable influence of the alloying elements Hf, Sn, Mo, which enhance the protective properties of the native passive film on alloy surface. Impedance spectra showed a passive film with two layers, an inner, capacitive, barrier, dense layer and an outer, less insulating, porous layer that confer both high corrosion resistance and bioactivity to the alloy. In vitro tests were carried out in order to evaluate the response of Human Umbilical Vein Endothelial Cells (HUVECs) to Ti-23Hf-3Mo-4Sn alloy in terms of cell viability, cell proliferation, phenotypic marker expression and nitric oxide release. The results indicate a similar level of cytocompatibility with HUVEC cells cultured on Ti-23Hf-3Mo-4Sn substrate and those cultured on the conventional CP-Ti and Ti-6Al-4V metallic materials. PMID:28773939

Lu{sub 2}O{sub 3}:Tb,Hf storage phosphor

Energy Technology Data Exchange (ETDEWEB)

Kulesza, Dagmara; Trojan-Piegza, Joanna [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zych, Eugeniusz, E-mail: zych@wchuwr.p [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie Street, 50-383 Wroclaw (Poland)

2010-03-15

Lu{sub 2}O{sub 3}:Tb,Hf ceramics containing 0.1% of Tb and 0-1.5% of Hf were prepared in reducing atmosphere at 1700 {sup o}C and their thermoluminescence properties were systematically studied. For comparison Tb,Ca co-doped specimen was also fabricated and investigated. The Tb,Hf ceramics shows basically a single TL band located around 180 {sup o}C as found with heating rate of 15 {sup o}C/min. Ceramics singly doped with Tb show complex TL glow curves indicating the presence of traps of very different depths. On the other hand Tb,Ca co-doping is beneficial for the development of shallow traps with the main TL band around 70 {sup o}C. Hence, the aliovalent impurities, Ca{sup 2+} and Hf{sup 4+}, strongly influenced the traps structure in Lu{sub 2}O{sub 3}:Tb ceramics, each of them in its own specific way. Isothermal decay of Lu{sub 2}O{sub 3}:Tb,Hf at 185 {sup o}C was recorded and its shape suggest that multiple hole trapping occurs in the Lu{sub 2}O{sub 3}:Tb,Hf ceramics. Due to the different traps depths the Lu{sub 2}O{sub 3}:Tb,Hf ceramics possess properties typical for storage phosphors, while Lu{sub 2}O{sub 3}:Tb,Ca is a persistent luminescent material rather.

Effects of HfO{sub 2}/Co interface and Co/HfO{sub 2} interface on anomalous Hall behavior in perpendicular Co/Pt multilayers

Energy Technology Data Exchange (ETDEWEB)

Jiang, Shao-Long [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Yang, Guang [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Teng, Jiao, E-mail: tengjiao@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Guo, Qi-Xun; Liu, Yi-Wei; Li, Xu-Jing [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

2017-07-01

Highlights: • Anomalous Hall effect in perpendicular Co/Pt multilayers is studied. • Thermally stable AHE feature is obtained in [Pt/Co]{sub 3}/HfO{sub 2}/Pt multilayers. • Good thermal stability is due to enhanced intrinsic and side-jump contributions. - Abstract: Effects of the HfO{sub 2}/Co interface and the Co/HfO{sub 2} interface on thermal stability of anomalous Hall effect (AHE) in perpendicular Co/Pt multilayers have been studied. It is observed that thermally stable AHE behavior cannot be obtained in perpendicular Co/Pt multilayers with the HfO{sub 2}/Co interface, mainly due to Co-Pt interdiffusion during annealing. In contrast, thermally stable AHE feature is observed in perpendicular Co/Pt multilayers with the Co/HfO{sub 2} interface despite Co-Pt interdiffusion, which is owing to the enhancement of the side jump and intrinsic contributions to the AHE through interfacial modification after annealing.

A routine high-precision method for Lu-Hf isotope geochemistry and chronology

Science.gov (United States)

Patchett, P.J.; Tatsumoto, M.

1981-01-01

A method for chemical separation of Lu and Hf from rock, meteorite and mineral samples is described, together with a much improved mass spectrometric running technique for Hf. This allows (i) geo- and cosmochronology using the176Lu???176Hf+??- decay scheme, and (ii) geochemical studies of planetary processes in the earth and moon. Chemical yields for the three-stage ion-exchange column procedure average 90% for Hf. Chemical blanks are international mass spectrometric standard; suitable aliquots, prepared from a single batch of JMC 475, are available from Denver. Lu-Hf analyses of the standard rocks BCR-1 and JB-1 are given. The potential of the Lu-Hf method in isotope geochemistry is assessed. ?? 1980 Springer-Verlag.

Human factors information system

International Nuclear Information System (INIS)

Goodman, P.C.; DiPalo, C.A.

1991-01-01

Nuclear power plant safety is dependent upon human performance related to plant operations. To provide improvements in human performance, data collection and assessment play key roles. This paper reports on the Human factors Information System (HFIS) which is designed to meet the needs of the human factors specialists of the United States Nuclear Regulatory Commission. These specialists identify personnel errors and provide guidance designed to prevent such errors. HFIS is a simple and modular system designed for use on a personal computer. It is designed to contain four separate modules that provide information indicative of program or function effectiveness as well as safety-related human performance based on programmatic and performance data. These modules include the Human Factors Status module; the Regulatory Programs module; the Licensee Event Report module; and the Operator Requalification Performance module. Information form these modules can either be used separately or can be combined due to the integrated nature of the system. HFIS has the capability, therefore, to provide insights into those areas of human factors that can reduce the probability of events caused by personnel error at nuclear power plants and promote the health and safety of the public. This information system concept can be applied to other industries as well as the nuclear industry

A novel process for preparation of titanium dioxide from Ti-bearing electric furnace slag: NH4HF2-HF leaching and hydrolyzing process.

Science.gov (United States)

Zheng, Fuqiang; Guo, Yufeng; Qiu, Guanzhou; Chen, Feng; Wang, Shuai; Sui, Yulei; Jiang, Tao; Yang, Lingzhi

2018-02-15

A novel process to prepare titanium dioxide from Ti-bearing electric furnace slag by NH 4 HF 2 -HF leaching and hydrolyzing process has been developed. In this present study, the effects of [NH 4 + ]/[F] mXolar ratio, leaching temperature, [F] concentration, liquid/solid mass ratio, leaching time on the Ti extraction, and the phase transformations have been investigated to reveal the leaching mechanism of Ti-bearing electric furnace slag in NH 4 HF 2 -HF solution. In the NH 4 HF 2 -HF leaching process, the MgTi 2 O 5 and Al 2 TiO 5 are converted to TiF 6 2- and Mg-Al-bearing precipitate. Ti extraction rate reached 98.84% under the optimal conditions. In addition, 98.25% iron ions can be removed in the presence of NaCl prior to hydrolysis process. The effects of pH and temperature on the selective hydrolysis of TiF 6 2- during hydrolysis process were also studied. In the hydrolysis process, the TiF 6 2- is converted to (NH 4 ) 2 TiOF 4 . By calcination, high grade TiO 2 powder with its purity of 99.88% was obtained, using which the products, well crystallized anatase and rutile, were obtained through roasting at 800°C and 1000°C, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Lifetime of the first excited 2{sup +} state in {sup 172}Hf and {sup 174}Hf

Energy Technology Data Exchange (ETDEWEB)

Gerst, Rosa-Belle; Stegemann, Simon; Jolie, Jan; Regis, Jean-Marc; Rudigier, Matthias; Saed-Samii, Nima; Zell, Karl Oskar [Institut fuer Kernphysik, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany)

2014-07-01

Using the {sup 170}Yb(α,2n) and {sup 172}Yb(α,2n) reactions the lifetimes of the first excited 2{sup +} state in {sup 172}Hf and {sup 174}Hf have been measured in fast-timing experiments using the Cologne Orange-Spectrometer and 6 LaBr{sub 3}(Ce)-Detectors. The lifetimes were obtained analyzing e{sup -}-γ-coincidence time-spectra with the slope method. The new and more precise lifetimes correct existing, outdated lifetimes in nuclear databases. Additionally, the systematics of the B(E2,2{sub 1}{sup +}→0{sub 1}{sup +}) is studied.

Hollow fiber liquid phase microextraction combined with graphite furnace atomic absorption spectrometry for the determination of methylmercury in human hair and sludge samples

Energy Technology Data Exchange (ETDEWEB)

Jiang Hongmei [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Bin [Department of Chemistry, Wuhan University, Wuhan 430072 (China)], E-mail: binhu@whu.edu.cn; Chen Beibei; Zu Wanqing [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

2008-07-15

Two methods, based on hollow fiber liquid-liquid-liquid (three phase) microextraction (HF-LLLME) and hollow fiber liquid phase (two phase) microextraction (HF-LPME), have been developed and critically compared for the determination of methylmercury content in human hair and sludge by graphite furnace atomic absorption spectrometry (GFAAS). In HF-LPME, methylmercury was extracted into the organic phase (toluene) prior to its determination by GFAAS, while inorganic mercury remained as a free species in the sample solution. In HF-LLLME, methylmercury was first extracted into the organic phase (toluene) and then into the acceptor phase (4% thiourea in 1 mol L{sup -1} HCl) prior to its determination by GFAAS, while inorganic mercury remained in the sample solution. The total mercury was determined by inductively coupled plasma-mass spectrometry (ICP-MS), and the levels of inorganic mercury in both HF-LLLME and HF-LPME were obtained by subtracting methylmercury from total mercury. The factors affecting the microextraction of methylmercury, including organic solvent, extraction time, stirring rate and ionic strength, were investigated and the optimal extraction conditions were established for both HF-LLLPME and HF-LPME. With a consumption of 3.0 mL of the sample solution, the enrichment factors were 204 and 55 for HF-LLLPME and HF-LPME, respectively. The limits of detection (LODs) for methylmercury were 0.1 {mu}g L{sup -1} and 0.4 {mu}g L{sup -1} (as Hg) with precisions (RSDs (%), c = 5 {mu}g L{sup -1} (as Hg), n = 5) of 13% and 11% for HF-LLLPME-GFAAS and HF-LPME-GFAAS, respectively. For ICP-MS determination of total mercury, a limit of detection of 39 ng L{sup -} {sup 1} was obtained. Finally, HF-LLLME-GFAAS was applied to the determination of methylmercury content in human hair and sludge, and the recoveries for the spiked samples were in the range of 99-113%. In order to validate the method, HF-LLLME-GFAAS was also applied to the analysis of a certified reference

Thermodynamic modeling of the Co–Hf system supported by key experiments and first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Lu, Xingxu [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Liu, Shuhong, E-mail: shhliu@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German Cooperation Group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Cheng, Kaiming; Tang, Ying [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Ou, Pengfei [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Nash, Philip [Thermal Processing Technology Center, Illinois Institute of Technology (IIT), 10 West 32nd Street, Chicago, IL 60616 (United States); Sundman, Bo [INSTN, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France); Du, Yong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German Cooperation Group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Zheng, Feng [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China)

2015-05-20

Highlights: • Heat contents of Co{sub 2}Hf and CoHf{sub 2} were measured by drop calorimetry. • Enthalpy of formation for Co{sub 23}Hf{sub 6} was computed via first-principles calculations. • Co–Hf system was assessed by means of CALPHAD approach. • Order–disorder model is used to describe B2 (CoHf) and A2 (βHf). • Glass forming range of the Co–Hf amorphous alloys was predicted. - Abstract: Phase equilibria and thermodynamic properties of the Co–Hf system were investigated via calorimetric measurements, first-principles calculations and thermodynamic modeling. Heat contents of Co{sub 2}Hf and CoHf{sub 2} were measured by drop calorimetry from 300 to 1200 °C. The enthalpy of formation for Co{sub 23}Hf{sub 6} at 0 K was computed via first-principles calculations. Based on the experimental measurements and first-principles calculations from the present work and the literature, the Co–Hf system was assessed by means of CALPHAD (CALculation of PHAse Diagram) approach. The excess Gibbs energy of solution phases was modeled with Redlich–Kister polynomial. Sublattice models were employed to describe the homogeneity ranges of Co{sub 2}Hf, CoHf and CoHf{sub 2}. The order–disorder transition between B2 (CoHf) and A2 (βHf) phases was taken into account in the current optimization. Using the optimized parameters, glass forming range (GFR) of the Co–Hf amorphous alloys was predicted to be 15–75 at.% Hf, which is in satisfactory agreement with the experimental observation.

Nuclear quadrupole interactions in ferroelectric compounds of HF/sup 181/

Energy Technology Data Exchange (ETDEWEB)

Kunzler, J V

1971-01-01

Measurements of nuclear quadrupole interaction constants in perovkite-type compounds of PbHfO/sub 3/, SnhfO/sub 3/, CaHfO/sub 3/ e SrHfO/sub 3/ have been performed using the perturbed angular correlation technique. A range of fundamental frequencies from 150 to 550 Megaradians per second was determined. The variation of quadrupole constants has been discussed through the molecular orbital theory.

Reliability assessment of ultra-thin HfO2 films deposited on silicon wafer

International Nuclear Information System (INIS)

Fu, Wei-En; Chang, Chia-Wei; Chang, Yong-Qing; Yao, Chih-Kai; Liao, Jiunn-Der

2012-01-01

Highlights: ► Nano-mechanical properties on annealed ultra-thin HfO 2 film are studied. ► By AFM analysis, hardness of the crystallized HfO 2 film significantly increases. ► By nano-indention, the film hardness increases with less contact stiffness. ► Quality assessment on the annealed ultra-thin films can thus be achieved. - Abstract: Ultra-thin hafnium dioxide (HfO 2 ) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO 2 films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO 2 films deposited on silicon wafers (HfO 2 /SiO 2 /Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO 2 (nominal thickness ≈10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO 2 phases for the atomic layer deposited HfO 2 . The HfSi x O y complex formed at the interface between HfO 2 and SiO 2 /Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO 2 film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically sensitive nano-indentation. Quality assessments on as-deposited and annealed HfO 2 films can be thereafter used to estimate the mechanical properties and adhesion of ultra-thin HfO 2

Chemical reaction at the interface between pentacene and HfO2

International Nuclear Information System (INIS)

Kang, S.J.; Yi, Y.; Kim, K.H.; Yoo, C.Y.; Moewes, A.; Cho, M.H.; Denlinger, J.D.; Whang, C.N.; Chang, G.S.

2005-01-01

The electronic structure and the interface formation at the interface region between pentacene and HfO2 are investigated using x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and x-ray emission spectroscopy (XES). The measured C 1s XPS spectra of pentacene indicate that chemical bonding occurs at the interface between pentacene and HfO2. The carbon of pentacene reacts with oxygen belonging to HfO2 and band bending occurs at the interface due to a redistribution of charge. The determined interface dipole and band bending between pentacene and HfO2 are 0.04 and 0.1 eV, respectively. The highest occupied molecular orbital (HOMO) level is observed at 0.68 eV below the Fermi level. This chemical reaction allows us to grow a pentacene film with large grains onto HfO2. We conclude that high performance pentacene thin film transistors can be obtained by inserting an ultrathin HfO2 layer between pentacene and a gate insulator

Habitability and Human Factors Contributions to Human Space Flight

Science.gov (United States)

Sumaya, Jennifer Boyer

2011-01-01

This slide presentation reviews the work of the Habitability and Human Factors Branch in support of human space flight in two main areas: Applied support to major space programs, and Space research. The field of Human Factors applies knowledge of human characteristics for the design of safer, more effective, and more efficient systems. This work is in several areas of the human space program: (1) Human-System Integration (HSI), (2) Orion Crew Exploration Vehicle, (3) Extravehicular Activity (EVA), (4) Lunar Surface Systems, (5) International Space Station (ISS), and (6) Human Research Program (HRP). After detailing the work done in these areas, the facilities that are available for human factors work are shown.

Surface characteristics of hydroxyapatite-coated layer prepared on nanotubular Ti–35Ta–xHf alloys by EB-PVD

Energy Technology Data Exchange (ETDEWEB)

Jeong, Yong-Hoon [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Biomechanics and Tissue Engineering Laboratory, Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Moon, Byung-Hak [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Brantley, William A. [Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, The Ohio State University, Columbus, OH (United States)

2013-12-31

In this study, we investigated the surface characteristics of hydroxyapatite (HA)-coated layers prepared by electron-beam physical vapor deposition (EB-PVD) on nanotubular Ti–35Ta–xHf alloys (x = 3, 7, and 15 wt.%). Ti–35Ta–xHf alloys were first prepared by arc melting. Formation of a nanotube structure on these alloys was achieved by an electrochemical method in 1 M H{sub 3}PO{sub 4} + 0.8 wt.% NaF electrolytes. The HA coatings were then deposited on the nanotubular surface by an EB-PVD method. The surface characteristics were analyzed by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction (XRD). The electrochemical behavior was examined using a potentiodynamic polarization test in 0.9% NaCl solution. The Ti–35Ta–xHf alloys had an equiaxed grain structure with α″ + β phases, and the α″ phase disappeared with increases in Hf content. The Ti–35Ta–15Hf alloy showed higher β-phase peak intensity in the XRD patterns than that for the lower Hf-content alloys. A highly ordered nanotubular oxide layer was formed on the Ti–35Ta–15Hf alloy, and the tube length depended on Hf content. The HA coating surface formed at traces of the nanotubular titanium oxide layer and completely covered the tips of the nanotubes with a cluster shape. From the potentiodynamic polarization tests, the incorporation of Hf element and formation of the nanotubular structure were the main factors for achieving lower current density. In particular, the surface of the HA coating on the nanotubular structure exhibited higher corrosion resistance than that of the nanotubular titanium oxide structure without an HA coating. - Highlights: • Hydroxyapatite (HA) was coated on nanotubular Ti–35Ta–xHf alloys, using EB-PVD. • Increasing the Hf content reduced the relative proportion of α″ martensite to β-Ti in the microstructures. • The detailed nanotubular structure formed by anodization depended on alloy composition

Surface characteristics of hydroxyapatite-coated layer prepared on nanotubular Ti–35Ta–xHf alloys by EB-PVD

International Nuclear Information System (INIS)

Jeong, Yong-Hoon; Moon, Byung-Hak; Choe, Han-Cheol; Brantley, William A.

2013-01-01

In this study, we investigated the surface characteristics of hydroxyapatite (HA)-coated layers prepared by electron-beam physical vapor deposition (EB-PVD) on nanotubular Ti–35Ta–xHf alloys (x = 3, 7, and 15 wt.%). Ti–35Ta–xHf alloys were first prepared by arc melting. Formation of a nanotube structure on these alloys was achieved by an electrochemical method in 1 M H 3 PO 4 + 0.8 wt.% NaF electrolytes. The HA coatings were then deposited on the nanotubular surface by an EB-PVD method. The surface characteristics were analyzed by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction (XRD). The electrochemical behavior was examined using a potentiodynamic polarization test in 0.9% NaCl solution. The Ti–35Ta–xHf alloys had an equiaxed grain structure with α″ + β phases, and the α″ phase disappeared with increases in Hf content. The Ti–35Ta–15Hf alloy showed higher β-phase peak intensity in the XRD patterns than that for the lower Hf-content alloys. A highly ordered nanotubular oxide layer was formed on the Ti–35Ta–15Hf alloy, and the tube length depended on Hf content. The HA coating surface formed at traces of the nanotubular titanium oxide layer and completely covered the tips of the nanotubes with a cluster shape. From the potentiodynamic polarization tests, the incorporation of Hf element and formation of the nanotubular structure were the main factors for achieving lower current density. In particular, the surface of the HA coating on the nanotubular structure exhibited higher corrosion resistance than that of the nanotubular titanium oxide structure without an HA coating. - Highlights: • Hydroxyapatite (HA) was coated on nanotubular Ti–35Ta–xHf alloys, using EB-PVD. • Increasing the Hf content reduced the relative proportion of α″ martensite to β-Ti in the microstructures. • The detailed nanotubular structure formed by anodization depended on alloy composition. • The

Large Magnetic Anisotropy in HfMnP

Science.gov (United States)

Parker, David; Lamichhane, Tej; Taufour, Valentin; Masters, Morgan; Thimmaiah, Srinivasa; Bud'Ko, Ser'gey; Canfield, Paul

We present a theoretical and experimental study of two little-studied manganese phosphide ferromagnets, HfMnP and ZrMnP, with Curie temperatures above room temperature. We find an anisotropy field in HfMnP approaching 10 T - larger than that of the permanent magnet workhorse NdFeB magnets. From theory we determine the source of this anisotropy. Our results show the potential of 3d-element-based magnetic materials for magnetic applications.

A comparative study of amorphous InGaZnO thin-film transistors with HfOxNy and HfO2 gate dielectrics

International Nuclear Information System (INIS)

Zou, Xiao; Tong, Xingsheng; Fang, Guojia; Yuan, Longyan; Zhao, Xingzhong

2010-01-01

High-κ HfO x N y and HfO 2 films are applied to amorphous InGaZnO (a-IGZO) devices as gate dielectric using radio-frequency reactive sputtering. The electrical characteristics and reliability of a-IGZO metal–insulator–semiconductor (MIS) capacitors and thin-film transistors (TFTs) are then investigated. Experimental results indicate that the nitrogen incorporation into HfO 2 can effectively improve the interface quality and enhance the reliability of the devices. Electrical properties with an interface-state density of 5.2 × 10 11 eV −1 cm −2 , capacitance equivalent thickness of 1.65 nm, gate leakage current density of 3.4 × 10 −5 A cm −2 at V fb +1 V, equivalent permittivity of 23.6 and hysteresis voltage of 110 mV are obtained for an Al/HfO x N y /a-IGZO MIS capacitor. Superior performance of HfO x N y /a-IGZO TFTs has also been achieved with a low threshold voltage of 0.33 V, a high saturation mobility of 12.1 cm 2 V −1 s −1 and a large on–off current ratio up to 7 × 10 7 (W/L = 500/20 µm) at 3 V

Ti-catalyzed HfSiO4 formation in HfTiO4 films on SiO2 studied by Z-contrast scanning electron microscopy

Directory of Open Access Journals (Sweden)

Elizabeth Ellen Hoppe

2013-08-01

Full Text Available Hafnon (HfSiO4 as it is initially formed in a partially demixed film of hafnium titanate (HfTiO4 on fused SiO2 is studied by atomic number (Z contrast high resolution scanning electron microscopy, x-ray diffraction, and Raman spectroscopy and microscopy. The results show exsoluted Ti is the catalyst for hafnon formation by a two-step reaction. Ti first reacts with SiO2 to produce a glassy Ti-silicate. Ti is then replaced by Hf in the silicate to produce HfSiO4. The results suggest this behavior is prototypical of other Ti-bearing ternary or higher order oxide films on SiO2 when film thermal instability involves Ti exsolution.

Solidification Rate Dependence of Microstructures and Transformation Behavior of Ti-Ni-Hf Alloys.

Science.gov (United States)

Kim, Dong-Jo; Kim, Yeon-Wook; Nam, Tae-Hyun

2018-09-01

The microstructures and transformation behavior of Ti-49Ni-20Hf, Ti-49.5Ni-20Hf and Ti-50.3Ni- 20Hf alloys, when prepared by conventional casting, were investigated and compared with the properties of the alloys prepared by melt spinning. The area fraction of (Ti,Hf)2Ni in Ti-Ni-Hf alloys decreased to 3.9% from 9.4% as Ni content rose to 50.3 at% from 49 at%. Several cracks were observed in the hot-rolled Ti-49Ni-20Hf alloy sheet but none were found in the Ti-50.3Ni-20Hf alloy sheet. The B2-B19' transformation start temperature (Ms) decreased to 476 K from 580 K as Ni content increased to 50.3 at% from 49 at%. All the as-spun ribbons were amorphous, and the activation energy for crystallization ranged from 167.8 kJ/mol to 182.7 kJ/mol based on Ni content. When annealing temperature ranged from 810 K to 873 K, crystalline Ti-Ni-Hf alloys without (Ti,Hf)2Ni particles were obtained. At annealing temperatures higher than 873 K, very fine (Ti,Hf)2Ni particles, less than 20 nm in size, were found embedded in a crystalline matrix.

Hf-Nd Isotopic Correlation in the Deccan Flood Basalt Province

Science.gov (United States)

Saha, A.; Basu, A. R.; Barling, J.; Anbar, A. D.; Hooper, P. R.

2001-12-01

Hafnium isotopes along with other isotopic and geochemical characteristics, including incompatible trace elements, of several of the lower formations of the Deccan Flood Basalt Province were analyzed to characterize petrogenesis of different tholeiitic lava suites, especially with respect to potential mantle and crustal sources. The rare earth elements of the different formations (from top to bottom- Mahabaleshwar, Ambenali, Bushe, Khandala and Neral) all show an LREE-enriched signature, concentrations varying between 30 to 60 times chondrite for La. (La/Lu)n values range from 4.1 to above 8 with the exception of Ambenali, which has a less LREE-enriched signature with (La/Lu)n values ranging between 3.6 to 5.3. Hafnium isotopic data of the lower formations of the Deccan show initial \\epsilonHf(T) values covering a range from -3 to -28. 176Lu/177Hf varies between 0.20 to 0.70. f(Lu/Hf) varies within a narrow range, between -0.90 to -0.97 while f(Sm/Nd) ranges from -0.84 to -0.86. Bushe gives the lowest range of \\epsilonHf(T) from -21 to -28 with the corresponding \\epsilonNd(T) varying between -4.0 and -16.9, while Khandala for almost the same range of neodymium isotopic values has \\epsilonHf(T) between -11 and -15. The \\epsilonHf(T) values of Neral is in between those of Khandala and Bushe, around -19. Ambenali, has the narrowest range with \\epsilonHf(T) of -3 and \\epsilonNd(T) between 3 and 5. The Ambenali suite reflects the least contaminated of the Deccan suite of lavas as analyzed here and previously confirmed by other isotopic studies. In Hf-Nd isotope correlation plot, the lower Deccan formations of Neral, Khandala and Bushe define individual subparallel arrays that are shallower than the oceanic basalt array and the overall terrestrial array, including the crustal array, although the bulk of the lower formation data fall within the crustal array of Vervoort et al (1999). From these subparallel Hf-Nd arrays, it is evident that the other end

QAPP for Hydraulic Fracturing (HF) Surface Spills Data Analysis

Science.gov (United States)

This QAPP provides information concerning the analysis of spills associated with hydraulic fracturing. This project is relevant to both the chemical mixing and flowback and produced water stages of the HF water cycle as found in the HF Study Plan.

Direct currents produced by hf heating of plasma

International Nuclear Information System (INIS)

Klima, R.

1974-01-01

In addition to the well-known diffusion currents, toroidal direct currents arise in h.f. heated plasmas as a result of a momentum transfer from the h.f. field to plasma particles. The estimates of steady-state conditions are given for these currents. Particularly, the possibility of stationary operation of a Tokamak device is analyzed. (author)

Analysis of enriched HF-UF6 systems. Influence by impurity and density upon the value of the multiplication

International Nuclear Information System (INIS)

Acosta, N.B.; Canavese, S.I.; Lopez, M.L.

1990-01-01

The purpose of this paper is analyzing the influence of impurity in hydrogen fluoride and in density variation (UF 6 -HF) upon the value of the effective multiplication factor (Kef) in enriched uranium hexafluoride and hydrogen fluoride systems. The identification of the values of such multiplication factors were performed by means of the Monte-Carlo (MONK V.II) code, which is specific for criticality problems. Diverse systems were considered by keeping the same geometry and varying the density value and the impurity percentages, while the assumptions made for each model were described on a case-by-case basis. Also, systems with and without water infinite reflector were evaluated. Finally, an analysis is made of the influence of each parameter upon the effective multiplication factor, in the postulated enriched UF 6 -HF systems. (Author) [es

Comparison of 14 MeV isomer production of 178m2Hf and 179m2Hf using Feshbach-Kerman-Koonin and exciton preequilibrium models

International Nuclear Information System (INIS)

Chadwick, M.B.; Young, P.G.

1993-01-01

The 178m2 Hf(16+) isomeric state has a 31-yr half life and could pose serious radioactive problems in nuclear fusion reactors if its production in 14 MeV neutron-induced reactions is significant. We present statistical/preequilibrium model calculations for the production of this isomer in the 179 Hf(n, 2n) 178m2 Hf reaction, as well as the 25-days 12.5 - isomer in the 179 Hf(n,n') 179m2 Hf reaction, using two different preequilibrium models: the exciton model and the Feshbach-Kerman-Koonin (FKK) theory. Our calculations which use the exciton model agree well with measurements, but those with the FKK theory underestimate measurements. Our calculations axe the first to probe angular momentum transfer effects in the FKK theory and suggest that, as it is presently applied, high spin-transfer reactions are underestimated. We suggest modifications to the FKK statistical averaging procedure which may result in an improved agreement with experiment

New Hf-Nd evidence supports a heterogeneous plume source for the Caribbean Plateau

International Nuclear Information System (INIS)

Thompson, P.M.E; Kempton, P.D; White, R.V; Kerr, A.C; Tarney, J.; Sauders, A.D

2001-01-01

Hf-Nd systematics provide us with a valuable tool for tracing mantle sources and signatures in ancient or altered rocks. Hf and Nd are amongst the most resistant of all elements to secondary alteration processes (Pearce et al., 1999) and hence can give us insights into the source compositions of altered plateau basalts that other isotopic systems will not. Here we use Hf-Nd systematics to probe the depths of the Cretaceous Caribbean Plateau, in order to characterise its isotope systematics, and hence determine the geochemical nature of the mantle plume responsible for its formation. Much of the plateau is already well characterised in terms of trace elements and isotopes such as Sr, Nd, Pb and Os (Kerr et al., 1997; White et al., 1999; Walker et al., 1999). Unfortunately, isotope system resetting due to sub- solidus alteration, amongst other factors, has ensured that these isotopes have been inconclusive in resolving many important issues, such as whether the Caribbean plateau is a product of an earlier Galapagos plume phase, and how the apparently unique Gorgona komatiites relate to the rest of the Caribbean plateau. We present new Hf-Nd isotopic data which reveal that the Caribbean plume must have been compositionally heterogeneous, comprising at least three different source components. We then compare this 'Caribbean plume' to other present-day plumes, (e.g. Galapagos) and from this speculate whether initial magmatism from the Galapagos plume could indeed have been responsible for the formation of the Caribbean Plateau (au)

Electric field gradients at 181Ta sites in HfOx

International Nuclear Information System (INIS)

Darriba, G.N.; Rodriguez, A.M.; Saitovitch, H.; Silva, P.R.J.; Pasquevich, A.F.

2007-01-01

In the present work we report preliminary results about the possibility to study properties of the order-disorder transition in HfO x solid solutions via the determination of the electric field gradient (EFG) at 181 Ta radioactive probes. Oxygen solution into the metal was achieved by arc melting stoichiometric amounts of metallic Hf and HfO 2 under argon atmosphere. Samples of HfO x with x=0.1 and 0.2 were prepared. Two types of samples were used for the perturbed angular correlation (PAC) experiments by doping alternatively with 181 Ta, by neutron irradiation, the metallic Hf or the hafnium oxide. The PAC results on both samples were identical, with disappearing hyperfine signals of the metal and the oxide, showing a complete diffusion of the probes independent of the way of doping. The PAC signal of the HfO x solid solution consisted in a wide distribution of EFGs due to the oxygen disorder. This scheme held even after long thermal treatments at high temperature (several days at 1273K). Annealing treatments at moderate temperature (600K) were also made. In these cases the samples were cooling at a very low rate. These results, together with those obtained by measuring samples below and above the order temperature are reported

Atomic scale engineering of HfO2-based dielectrics for future DRAM applications

International Nuclear Information System (INIS)

Dudek, Piotr

2011-01-01

Modern dielectrics in combination with appropriate metal electrodes have a great potential to solve many difficulties associated with continuing miniaturization process in the microelectronic industry. One significant branch of microelectronics incorporates dynamic random access memory (DRAM) market. The DRAM devices scaled for over 35 years starting from 4 kb density to several Gb nowadays. The scaling process led to the dielectric material thickness reduction, resulting in higher leakage current density, and as a consequence higher power consumption. As a possible solution for this problem, alternative dielectric materials with improved electrical and material science parameters were intensively studied by many research groups. The higher dielectric constant allows the use of physically thicker layers with high capacitance but strongly reduced leakage current density. This work focused on deposition and characterization of thin insulating layers. The material engineering process was based on Si cleanroom compatible HfO 2 thin films deposited on TiN metal electrodes. A combined materials science and dielectric characterization study showed that Ba-added HfO 2 (BaHfO 3 ) films and Ti-added BaHfO 3 (BaHf 0.5 Ti 0.5 O 3 ) layers are promising candidates for future generation of state-of-the-art DRAMs. In especial a strong increase of the dielectric permittivity k was achieved for thin films of cubic BaHfO 3 (k∝38) and BaHf 0.5 Ti 0.5 O 3 (k∝90) with respect to monoclinic HfO 2 (k∝19). Meanwhile the CET values scaled down to 1 nm for BaHfO 3 and ∝0.8 nm for BaHf 0.5 Ti 0.5 O 3 with respect to HfO 2 (CET=1.5 nm). The Hf 4+ ions substitution in BaHfO 3 by Ti 4+ ions led to a significant decrease of thermal budget from 900 C for BaHfO 3 to 700 C for BaHf 0.5 Ti 0.5 O 3 . Future studies need to focus on the use of appropriate metal electrodes (high work function) and on film deposition process (homogeneity) for better current leakage control. (orig.)

Human Factors Review Plan

International Nuclear Information System (INIS)

Paramore, B.; Peterson, L.R.

1985-12-01

''Human Factors'' is concerned with the incorporation of human user considerations into a system in order to maximize human reliability and reduce errors. This Review Plan is intended to assist in the assessment of human factors conditions in existing DOE facilities. In addition to specifying assessment methodologies, the plan describes techniques for improving conditions which are found to not adequately support reliable human performance. The following topics are addressed: (1) selection of areas for review describes techniques for needs assessment to assist in selecting and prioritizing areas for review; (2) human factors engineering review is concerned with optimizing the interfaces between people and equipment and people and their work environment; (3) procedures review evaluates completeness and accuracy of procedures, as well as their usability and management; (4) organizational interface review is concerned with communication and coordination between all levels of an organization; and (5) training review evaluates training program criteria such as those involving: trainee selection, qualification of training staff, content and conduct of training, requalification training, and program management

Human Factors Review Plan

Energy Technology Data Exchange (ETDEWEB)

Paramore, B.; Peterson, L.R. (eds.)

1985-12-01

''Human Factors'' is concerned with the incorporation of human user considerations into a system in order to maximize human reliability and reduce errors. This Review Plan is intended to assist in the assessment of human factors conditions in existing DOE facilities. In addition to specifying assessment methodologies, the plan describes techniques for improving conditions which are found to not adequately support reliable human performance. The following topics are addressed: (1) selection of areas for review describes techniques for needs assessment to assist in selecting and prioritizing areas for review; (2) human factors engineering review is concerned with optimizing the interfaces between people and equipment and people and their work environment; (3) procedures review evaluates completeness and accuracy of procedures, as well as their usability and management; (4) organizational interface review is concerned with communication and coordination between all levels of an organization; and (5) training review evaluates training program criteria such as those involving: trainee selection, qualification of training staff, content and conduct of training, requalification training, and program management.

Heavy ion studies with CMS HF calorimeter

International Nuclear Information System (INIS)

Damgov, I.; Genchev, V.; Kolosov, V.A.; Lokhtin, I.P.; Petrushanko, S.V.; Sarycheva, L.I.; Teplov, S.Yu.; Shmatov, S.V.; Zarubin, P.I.

2001-01-01

The capability of the very forward (HF) calorimeter of the CMS detector at LHC to be applied to specific studies with heavy ion beams is discussed. The simulated responses of the HF calorimeter to nucleus-nucleus collisions are used for the analysis of different problems: reconstruction of the total energy flow in the forward rapidity region, accuracy of determination of the impact parameter of collision, study of fluctuations of the hadronic-to-electromagnetic energy ratio, fast inelastic event selection

Hf{sub 3}Fe{sub 4}Sn{sub 4} and Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x}: Two stannide intermetallics with low-dimensional iron sublattices

Energy Technology Data Exchange (ETDEWEB)

Calta, Nicholas P. [Department of Chemistry, Northwestern University (United States); Kanatzidis, Mercouri G., E-mail: m-kanatzidis@northwestern.edu [Department of Chemistry, Northwestern University (United States); Materials Science Division, Argonne National Laboratory (United States)

2016-04-15

This article reports two new Hf-rich intermetallics synthesized using Sn flux: Hf{sub 3}Fe{sub 4}Sn{sub 4} and Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x}. Hf{sub 3}Fe{sub 4}Sn{sub 4} adopts an ordered variant the Hf{sub 3}Cu{sub 8} structure type in orthorhombic space group Pnma with unit cell edges of a=8.1143(5) Å, b=8.8466(5) Å, and c=10.6069(6) Å. Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x}, on the other hand, adopts a new structure type in Cmc2{sub 1} with unit cell edges of a=5.6458(3) Å, b=35.796(2) Å, and c=8.88725(9) Å for x=0. It exhibits a small amount of phase width in which Sn substitutes on one of the Fe sites. Both structures are fully three-dimensional and are characterized by pseudo one- and two-dimensional networks of Fe–Fe homoatomic bonding. Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x} exhibits antiferromagnetic order at T{sub N}=46(2) K and its electrical transport behavior indicates that it is a normal metal with phonon-dictated resistivity. Hf{sub 3}Fe{sub 4}Sn{sub 4} is also an antiferromagnet with a rather high ordering temperature of T{sub N}=373(5) K. Single crystal resistivity measurements indicate that Hf{sub 3}Fe{sub 4}Sn{sub 4} behaves as a Fermi liquid at low temperatures, indicating strong electron correlation. - Graphical abstract: Slightly different growth conditions in Sn flux produce two new intermetallic compounds: Hf{sub 3}Fe{sub 4}Sn{sub 4} and Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x}. - Highlights: • Single crystals of both Hf{sub 3}Fe{sub 4}Sn{sub 4} and Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x} were grown using Sn flux. • The crystal structures were determined using single crystal X-ray diffraction. • The Fe moments in Hf{sub 3}Fe{sub 4}Sn{sub 4} display AFM order below T{sub N}=373 K. • The Fe moments in Hf{sub 9}Fe{sub 4−x}Sn{sub 10+x} display AFM order below T{sub N}=46 K.

Comparison of HF radar measurements with Eulerian and Lagrangian surface currents

Science.gov (United States)

Röhrs, Johannes; Sperrevik, Ann Kristin; Christensen, Kai Håkon; Broström, Göran; Breivik, Øyvind

2015-05-01

High-frequency (HF) radar-derived ocean currents are compared with in situ measurements to conclude if the radar observations include effects of surface waves that are of second order in the wave amplitude. Eulerian current measurements from a high-resolution acoustic Doppler current profiler and Lagrangian measurements from surface drifters are used as references. Directional wave spectra are obtained from a combination of pressure sensor data and a wave model. Our analysis shows that the wave-induced Stokes drift is not included in the HF radar-derived currents, that is, HF radars measure the Eulerian current. A disputed nonlinear correction to the phase velocity of surface gravity waves, which may affect HF radar signals, has a magnitude of about half the Stokes drift at the surface. In our case, this contribution by nonlinear dispersion would be smaller than the accuracy of the HF radar currents, hence no conclusion can be made. Finally, the analysis confirms that the HF radar data represent an exponentially weighted vertical average where the decay scale is proportional to the wavelength of the transmitted signal.

Nanotube formation and morphology change of Ti alloys containing Hf for dental materials use

International Nuclear Information System (INIS)

Jeong, Yong-Hoon; Lee, Kang; Choe, Han-Cheol; Ko, Yeong-Mu; Brantley, William A.

2009-01-01

In this paper, Ti-Hf (10, 20, 30 and 40 wt.%) alloys were prepared by arc melting, and subjected to heat treatment for 24 h at 1000 o C in an argon atmosphere. Formation of surface nanotubes was achieved by anodizing a Ti-Hf alloy in 1.0 M H 3 PO 4 electrolytes with small amounts of NaF at room temperature. Microstructures of the alloys and nanotube morphology were examined by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The homogenized Ti-Hf alloys had a needle-like microstructure of α phase, and nanotubes formed on Ti-xHf alloys had the anatase phase after treatment that promoted crystallization. Uniform nanotubes formed for Hf contents up to 20 wt.%. Irregular nanotubes formed on the Ti-30Hf and Ti-40Hf alloys. The structure of the irregular layers on the Ti-30Hf and Ti-40Hf alloys had nanotubes of two sizes. Increasing the Hf content in Ti led to the formation of nanotubes with more narrow size. The pores in the nanotubes typically had a diameter ranging from 80-120 nm and a length of approximately 1.7 μm. It is concluded that nanotube morphology on Ti-Hf alloys can controlled by varying the amount of Hf.

The development of human factors technologies -The development of human factors experimental evaluation techniques-

International Nuclear Information System (INIS)

Shim, Bong Sik; Oh, In Suk; Cha, Kyung Hoh; Lee, Hyun Chul

1995-07-01

In this year, we studied the followings: 1) Development of operator mental workload evaluation techniques, 2) Development of a prototype for preliminary human factors experiment, 3) Suitability test of information display on a large scale display panel, 4) Development of guidelines for VDU-based control room design, 5) Development of integrated test facility (ITF). 6) Establishment of an eye tracking system, and we got the following results: 1) Mental workload evaluation techniques for MMI evaluation, 2) PROTOPEX (PROTOtype for preliminary human factors experiment) for preliminary human factors experiments, 3) Usage methods of APTEA (Analysis-Prototyping-Training-Experiment-Analysis) experiment design, 4) Design guidelines for human factors verification, 5) Detail design requirements and development plan of ITF, 6) Eye movement measurement system. 38 figs, 20 tabs, 54 refs. (Author)

Oxidation behavior of TiC, ZrC, and HfC dispersed in oxide matrices

International Nuclear Information System (INIS)

Arun, R.; Subramanian, M.; Mehrotra, G.M.

1990-01-01

The oxidation behavior of hot pressed TiC-Al 2 O 3 , TiC-ZrO 2 , ZrC-ZrO 2 , and HfC-HfO 2 composites has been investigated at 1273 K. The oxidation of TiC, ZrC, and HfC in hot-pressed composites containing ZrO 2 and HfO 2 has been found to be extremely rapid. The kinetics of oxidation of TiC and a 90 wt% TiC-Al 2 O 3 composite appear to be faster compared to that of pure TiC. X-ray diffraction results for hot-pressed ZrC-HfO 2 and HfC-HfO 2 composites indicate partial stabilization of tetragonal ZrO 2 and HfO 2 phases in these composites

[Effect of a multifunctional instrument (HF scissors) in parotis surgery].

Science.gov (United States)

Strauss, G; Schaller, S; Gollnick, I

2014-03-01

Lateral parotidectomy is a demanding surgical procedure and requires a large number of instruments with a high frequency (HF) of alternating. Many functions, such as preparing, spreading, coagulating and cutting could be combined by using scissors with an integrated function of bipolar coagulation. This study has targeted an investigation of technical application, influence on surgery time, frequency of HF application and change of instruments. In the period between 01 April 2011 and 30 September 2012 (18 months) 35 procedures of lateral parotidectomy in 35 patients were investigated. In all cases lateral parotidectomy was carried out with a similar technique (modified extracapsular preparation). Workflow data were used from a control group in the period between 01 January 2009 and 31 December 2010 (24 months). The following parameters from both groups were documented and evaluated: incision-suture times (subdivided into nine sections of the procedure), change of instruments, period of application for HF function and early facial nerve function (6 h and 6 days after surgery according to House-Brackmann). Additionally, in the HF+ group a questionnaire that facilitated subjective evaluation of instruments was analyzed. It was possible to perform the surgery in both groups with neither technical nor surgical intraoperative complications. Incision-suture times showed an average reduction of 31.6 min (34.8 %) in the HF+ group. There was a reduction in the change of instruments compared to a conventional group (CONV) by up to 62.7 %. With the deployment of HF scissors there was a clear increase in the use of HF surgery by more than 100 % when comparing incision-suture times. Evaluation of both groups according to House-Brackmann showed a similar postoperative facial nerve function. The surgeons involved were of the opinion that in all 35 surgeries with HF scissors the intervention was easier and more comfortable. The use of HF scissors is appropriate for parotid gland

Creep Properties of NiAl-1Hf Single Crystals Re-Investigated

Science.gov (United States)

Whittenberger, J. Daniel; Locci, Ivan E.; Darolia, Ram; Bowman, Randy R.

2000-01-01

ingots were subjected to several heat treatment schedules, examined by transmission electron microscopy, and tested in both compression and tension. An example of the microstructure found in a [001]-oriented NiAl-1Hf specimen after a solution treatment at 1317 C for 50 hr followed by air cooling is illustrated in the image on the left, where the NiAl matrix contains a uniform distribution of nanometer-scale Gphase (Ni16Hf6Si7) precipitates. Other heat treating schedules produced microstructures with nanometer-sized G-phase cubes and plates or, in an extreme case, produced a microstructure with all the G-phase converted to Heusler (Ni2AlHf) particles. The results of 1027 C creep strength and strain rate testing are illustrated which summarizes data from tensile and compressive testing of samples cut from all four NiAl-1Hf ingots and subjected to a variety of heat treatment schedules. With one exception, all the strength values lie in a narrow band that spans six orders of magnitude in strain rate. The only factor that produced results outside of this band was the heat treatment schedule that dissolved all the G-phase and replaced it with Heusler precipitates. The results portrayed in this figure lead to the important practical conclusion that the elevated-temperature creep properties of NiAl-1Hf single crystals are reproducible and are not affected by small variations in alloy chemistry from ingot to ingot or by different initial distributions of G-phase in the heat-treated alloy. The only variable in this study that produced a significant and delerious effect on mechanical strength was a post-solution heat treatment that lead to the complete disappearance of the G-phase in favor of Heusler precipitates.

Human Factors in Marine Casualties

Directory of Open Access Journals (Sweden)

Jelenko Švetak

2002-05-01

Full Text Available Human factors play an important role in the origin of accidents,and it is commonly claimed that between seventy andninety-five percent of industrial and transport accidents involvehuman factors, see Figure 1.Some authorities, however, claim that ultimately, all accidentsinvolve human factors.

Effect of La doping on interface barrier between Si-passivated Ge and insulating HfO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kolomiiets, Nadiia M.; Afanas' ev, Valery V.; Madia, Oreste; Stesmans, Andre [Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium); Cott, Daire J.; Collaert, Nadine [Imec, Kapeldreef 75, 3001 Leuven (Belgium); Thean, Aaron [Imec, Kapeldreef 75, 3001 Leuven (Belgium); National University of Singapore (Singapore)

2016-12-15

By analyzing internal photoemission of electrons from Si/SiO{sub x}-passivated Ge into insulating HfO{sub 2} we found that insertion of additional La interlayer between SiO{sub x} and HfO{sub 2} leads to dramatic increase (more than by factor of 20) of the barrier transparency. However, no measurable variation of the interface barrier height is observed suggesting that La induces intermixing of near-interface oxide stack resulting in development of additional density of states corresponding to conduction band of LaO{sub x} and HfO{sub x} sub-networks. At the same time, photoemission results indicate the presence of discrete positive charges in the near-interface oxide layer which may explain the observed ∝1 V shift of capacitance-voltage curves. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Low-Frequency Waves in HF Heating of the Ionosphere

Science.gov (United States)

Sharma, A. S.; Eliasson, B.; Milikh, G. M.; Najmi, A.; Papadopoulos, K.; Shao, X.; Vartanyan, A.

2016-02-01

Ionospheric heating experiments have enabled an exploration of the ionosphere as a large-scale natural laboratory for the study of many plasma processes. These experiments inject high-frequency (HF) radio waves using high-power transmitters and an array of ground- and space-based diagnostics. This chapter discusses the excitation and propagation of low-frequency waves in HF heating of the ionosphere. The theoretical aspects and the associated models and simulations, and the results from experiments, mostly from the HAARP facility, are presented together to provide a comprehensive interpretation of the relevant plasma processes. The chapter presents the plasma model of the ionosphere for describing the physical processes during HF heating, the numerical code, and the simulations of the excitation of low-frequency waves by HF heating. It then gives the simulations of the high-latitude ionosphere and mid-latitude ionosphere. The chapter also briefly discusses the role of kinetic processes associated with wave generation.

Human factors and safe patient care.

Science.gov (United States)

Norris, Beverley

2009-03-01

This paper aims to introduce the topic of human factors to nursing management and to identify areas where it can be applied to patient safety. Human factors is a discipline established in most safety critical industries and uses knowledge about human behaviour in the analysis and design of complex systems, yet it is relatively new to many in healthcare. Most safety critical industries have developed tools and techniques to apply human factors to system design, and these have been reviewed together with those resources already available for use in healthcare. Models of human behaviour such as the nature and patterns of human error, information processing, decision-making and team work have clear applications to healthcare. Human factors focus on a system view of safety, and propose that safety should, where possible, be 'designed in'. Other interventions such as building defences, mitigating hazards and education and training should only be used where design solutions cannot be found. Simple human factors principles such as: designing for standardization; the involvement of users and staff in designing services and procuring equipment; understanding how errors occur; and the workarounds that staff will inevitably take are vital considerations in improving patient safety. Opportunities for the application of human factors to healthcare and improved patient safety are discussed. Some existing tools and techniques for applying human factors in nursing management are also presented.

Human factors in nuclear safety oversight

International Nuclear Information System (INIS)

Taylor, K.

1989-01-01

The mission of the nuclear safety oversight function at the Savannah River Plant is to enhance the process and nuclear safety of site facilities. One of the major goals surrounding this mission is the reduction of human error. It is for this reason that several human factors engineers are assigned to the Operations assessment Group of the Facility Safety Evaluation Section (FSES). The initial task of the human factors contingent was the design and implementation of a site wide root cause analysis program. The intent of this system is to determine the most prevalent sources of human error in facility operations and to assist in determining where the limited human factors resources should be focused. In this paper the strategy used to educate the organization about the field of human factors is described. Creating an awareness of the importance of human factors engineering in all facets of design, operation, and maintenance is considered to be an important step in reducing the rate of human error

Crystal structures of KM(AsF{sub 6}){sub 3} (M{sup 2+} = Mg, Co, Mn, Zn), KCu(SbF{sub 6}){sub 3} and [Co(HF){sub 2}]Sr[Sr(HF)]{sub 2}-[Sr(HF){sub 2}]{sub 2}[AsF{sub 6}]{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Mazej, Zoran; Goreshnik, Evgeny [Jozef Stefan Institute, Ljubljana (Slovakia). Dept. of Inorganic Chemisrty and Technology

2015-05-01

The KM(AsF{sub 6}){sub 3} (M{sup 2+} = Mg, Co, Mn, Zn) and KCu(SbF{sub 6}){sub 3} compounds crystallize isotypically to previously known KNi(AsF{sub 6}){sub 3}. The main features of the structure of these compounds are rings of MF{sub 6} octahedra sharing apexes with AsF{sub 6} octahedra connected into infinite tri-dimensional frameworks. In this arrangement cavities are formed where K{sup +} cations are placed. Single crystals of CoSr{sub 5}(AsF{sub 6}){sub 12}.8HF were obtained as one of the products after the crystallization of 3KF/CoF{sub 2}/SrF{sub 2} mixture in the presence of AsF{sub 5} in anhydrous HF. The CoSr{sub 5}(AsF{sub 6}){sub 12}.8HF is monoclinic, C/2c (No.15), with a = 26.773(5) Aa, b = 10.087(2) Aa, c = 21.141(5) Aa, β = 93.296(13) {sup circle}, V = 5699.9(19) Aa{sup 3} at 200 K, and Z = 4. There are three crystallographically non-equivalent Sr{sup 2+} cations in the crystal structure of CoSr{sub 5}(AsF{sub 6}){sub 12}.8HF. The Sr1 is coordinated by ten fluorine atoms from eight different [AsF{sub 6}]- anions, meanwhile Sr2 and Sr3 are bound to nine fluorine atoms provided by one HF and eight AsF{sub 6} units or by two HF and six AsF{sub 6} units, respectively. The Co{sup 2+} is coordinated distorted-octahedrally by six fluorine atoms from two HF molecules and four different AsF{sub 6} units. All those moieties in the crystal structure of [Co(HF){sub 2}]Sr[Sr(HF)]{sub 2}[Sr(HF){sub 2}]{sub 2}[AsF{sub 6}]{sub 12} are connected into tridimensional framework. The CoSr{sub 5}(AsF{sub 6}){sub 12}.8HF is a unique example of compound where HF molecules are directly bound via fluorine atoms to two different metal centres.

Study of bulk Hafnium oxide (HfO2) under compression

Science.gov (United States)

Pathak, Santanu; Mandal, Guruprasad; Das, Parnika

2018-04-01

Hafnium oxide (HfO2) is a technologically important material. This material has K-value of 25 and band gap 5.8 eV. A k value of 25-30 is preferred for a gate dielectric [1]. As it shows good insulating and capacitive properties, HfO2 is being considered as a replacement to SiO2 in microelectronic devices as gate dielectrics. On the other hand because of toughening mechanism due to phase transformation induced by stress field observed in these oxides, HFO2 has been a material of investigations in various configurations for a very long time. However the controversies about phase transition of HfO2 under pressure still exists. High quality synchrotron radiation has been used to study the structural phase transition of HfO2 under pressure.

Metal-assisted chemical etching in HF/Na2S2O8 OR HF/KMnO4 produces porous silicon

NARCIS (Netherlands)

Hadjersi, T.; Gabouze, N.; Kooij, Ernst S.; Zinine, A.; Zinine, A.; Ababou, A.; Chergui, W.; Cheraga, H.; Belhousse, S.; Djeghri, A.

2004-01-01

A new metal-assisted chemical etching method using Na2S2O8 or KMnO4 as an oxidizing agent was proposed to form a porous silicon layer on a highly resistive p-type silicon. A thin layer of Ag or Pd is deposited on the Si(100) surface prior to immersion in a solution of HF and Na2S2O8 or HF and KMnO4.

Human factors in resuscitation teaching.

Science.gov (United States)

Norris, Elizabeth M; Lockey, Andrew S

2012-04-01

There is an increasing interest in human factors within the healthcare environment reflecting the understanding of their impact on safety. The aim of this paper is to explore how human factors might be taught on resuscitation courses, and improve course outcomes in terms of improved mortality and morbidity for patients. The delivery of human factors training is important and this review explores the work that has been delivered already and areas for future research and teaching. Medline was searched using MESH terms Resuscitation as a Major concept and Patient or Leadership as core terms. The abstracts were read and 25 full length articles reviewed. Critical incident reporting has shown four recurring problems: lack of organisation at an arrest, lack of equipment, non functioning equipment, and obstructions preventing good care. Of these, the first relates directly to the concept of human factors. Team dynamics for both team membership and leadership, management of stress, conflict and the role of debriefing are highlighted. Possible strategies for teaching them are discussed. Four strategies for improving human factors training are discussed: team dynamics (including team membership and leadership behaviour), the influence of stress, debriefing, and conflict within teams. This review illustrates how human factor training might be integrated further into life support training without jeopardising the core content and lengthening the courses. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Small signal gain measurements in a small scale HF overtone laser

Energy Technology Data Exchange (ETDEWEB)

Wisniewski, C.F.; Hewett, K.B.; Manke, G.C. II; Hager, G.D. [Air Force Research Laboratory, Directed Energy Directorate, 3550 Aberdeen Ave SE, Kirtland AFB, NM 87117-5776 (United States); Crowell, P.G. [Northrup Grumman Information Technology, Science and Technology Operating Unit, Advanced Technology Division, P.O. Box 9377, Albuquerque, NM 87119-9377 (United States); Truman, C.R. [Mechanical Engineering Department, University of New Mexico, Albuquerque, NM 87131 (United States)

2003-07-01

The overtone gain medium of a small-scale HF overtone laser was probed using a sub-Doppler tunable diode laser. Two-dimensional spatially resolved small signal gain and temperature maps were generated for several ro-vibrational transitions in the HF (v=2{yields}v=0) overtone band. Our results compare well with previous measurements of the overtone gain in a similar HF laser device. (orig.)

Critical human-factors issues in nuclear-power regulation and a recommended comprehensive human-factors long-range plan. Executive summary

International Nuclear Information System (INIS)

Hopkins, C.O.; Snyder, H.L.; Price, H.E.; Hornick, R.J.; Mackie, R.R.; Smillie, R.J.; Sugarman, R.C.

1982-08-01

This comprehensive long-range human factors plan for nuclear reactor regulation was developed by a Study Group of the Human Factors Society, Inc. This Study Group was selected by the Executive Council of the Society to provide a balanced, experienced human factors perspective to the applications of human factors scientific and engineering knowledge to nuclear power generation. The report is presented in three volumes. Volume 1 contains an Executive Summary of the 18-month effort and its conclusions. Volume 2 summarizes all known nuclear-related human factors activities, evaluates these activities wherever adequate information is available, and describes the recommended long-range (10-year) plan for human factors in regulation. Volume 3 elaborates upon each of the human factors issues and areas of recommended human factors involvement contained in the plan, and discusses the logic that led to the recommendations

Suspended HfO2 photonic crystal slab on III-nitride/Si platform

International Nuclear Information System (INIS)

Wang, Yongjin; Feng, Jiao; Cao, Ziping; Zhu, Hongbo

2014-01-01

We present here the fabrication of suspended hafnium oxide (HfO 2 ) photonic crystal slab on a III-nitride/Si platform. The calculations are performed to model the suspended HfO 2 photonic crystal slab. Aluminum nitride (AlN) film is employed as the sacrificial layer to form air gap. Photonic crystal patterns are defined by electron beam lithography and transferred into HfO 2 film, and suspended HfO 2 photonic crystal slab is achieved on a III-nitride/Si platform through wet-etching of AlN layer in the alkaline solution. The method is promising for the fabrication of suspended HfO 2 nanostructures incorporating into a III-nitride/Si platform, or acting as the template for epitaxial growth of III-nitride materials. (orig.)

Integrated magnetics design for HF-link power converters

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper deals with the design of integrated magnetics for HF-link converters, where the two integrated magnetic components on the same core do not necessarily belong to the same voltage loop. Depending on the specific HF-link converter topology, the proposed integrated magnetics can either alleviate the derivation of independent auxiliary supply voltages from the main transformer or integrate other magnetic structures, thus saving board space and cutting costs. (au)

Fretting wear of ZrN and Zr(21% Hf)N coatings

Energy Technology Data Exchange (ETDEWEB)

Atar, E. [Gebze Inst. of Tech., Material Science and Engineering Dept., Kocaeli (Turkey); Cimenoglu, H.; Kayali, E.S. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Engineering, Istanbul (Turkey)

2004-07-01

In this study, the wear behaviours of ZrN and Zr(21% Hf)N coatings, deposited on hardened AISI D2 cold work tool steel were examined by a fretting wear tester. The hardness of ZrN and Zr(21% Hf)N coatings were almost the same, where as they exhibited different wear resistance. Addition of 21% Hf to ZrN coating achieved about 25% increase in the wear resistance. (orig.)

Fretting wear of ZrN and Zr(21% Hf)N coatings

International Nuclear Information System (INIS)

Atar, E.; Cimenoglu, H.; Kayali, E.S.

2004-01-01

In this study, the wear behaviours of ZrN and Zr(21% Hf)N coatings, deposited on hardened AISI D2 cold work tool steel were examined by a fretting wear tester. The hardness of ZrN and Zr(21% Hf)N coatings were almost the same, where as they exhibited different wear resistance. Addition of 21% Hf to ZrN coating achieved about 25% increase in the wear resistance. (orig.)

Reliability assessment of ultra-thin HfO{sub 2} films deposited on silicon wafer

Energy Technology Data Exchange (ETDEWEB)

Fu, Wei-En [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321 Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Chang, Chia-Wei [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Chang, Yong-Qing [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321 Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Yao, Chih-Kai [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Jiunn-Der, E-mail: jdliao@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

2012-09-01

Highlights: Black-Right-Pointing-Pointer Nano-mechanical properties on annealed ultra-thin HfO{sub 2} film are studied. Black-Right-Pointing-Pointer By AFM analysis, hardness of the crystallized HfO{sub 2} film significantly increases. Black-Right-Pointing-Pointer By nano-indention, the film hardness increases with less contact stiffness. Black-Right-Pointing-Pointer Quality assessment on the annealed ultra-thin films can thus be achieved. - Abstract: Ultra-thin hafnium dioxide (HfO{sub 2}) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO{sub 2} films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO{sub 2} films deposited on silicon wafers (HfO{sub 2}/SiO{sub 2}/Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO{sub 2} (nominal thickness Almost-Equal-To 10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO{sub 2} phases for the atomic layer deposited HfO{sub 2}. The HfSi{sub x}O{sub y} complex formed at the interface between HfO{sub 2} and SiO{sub 2}/Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO{sub 2} film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically

Simultaneous measurements of HF-enhanced plasma waves and artificial field-aligned irregularities at Arecibo

International Nuclear Information System (INIS)

Noble, S.T.; Djuth, F.T.

1990-01-01

Two radar systems with beams intersecting in the HF-modified F region were used to simultaneously measure HF-enhanced plasma lines (HFPLs) and artificial geomagnetic field-aligned irregularities (AFAIs). The Arecibo 430-MHz radar was used for the HFPL observations, and a portable 49.92-MHz backscatter radar was deployed on the island of Guadeloupe to monitor the AFAIs. The experiment was desgined to examine the degree to which HF-induced plasma turbulence influences the development of AFAIs. When the HF beam is stepped up in power, sustained HFPLs and AFAIs are first observed at the same HF power level, indicating that ponderomotively driven instabilities may be involved in the early time development of AFAIs. As the HF power is increased, the HFPL backscatter power begins to saturate at ∼70 MW effective radiated power (ERP). However, the backscatter from AFAIs is linearly dependent on HF power, even at the highest (120 MW ERP) HF power levels available at Arecibo. This suggests that additional processes may contribute to the development of AFAIs. For example, ponderomotively driven instabilities may give rise to weak geomagnetic field-aligned irregularities that are subsequently driven unstable by processes excited near the upper hybrid resonance. It is also likely that AFAIs greatly impact the development of HF-induced plasma turbulence at late times (>1 s) following HF turn-on. Once the ionosphere is preconditioned by high-power HF modifications, AFAIs and HFPLs can be simultaneously sustained at a much lower HF power level than that needed to originally excite them. The nature of the preconditioning process is currently not well understood. New theoretical initiatives are clearly needed to guide future experimental activity in this area

Pulsed inductive HF laser

Energy Technology Data Exchange (ETDEWEB)

Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)

2016-03-31

We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

An improvement of the applicability of human factors guidelines for coping with human factors issues in nuclear power plants

International Nuclear Information System (INIS)

Lee, Y. H.; Lee, J. Y.

2003-01-01

Human factors have been well known as one of the key factors to the system effectiveness as well as the efficiency and safety of nuclear power plants(NPPs). Human factors engineering(HFE) are included in periodic safety review(PSR) on the existing NPPs and the formal safety assessment for the new ones. However, HFE for NPPs is still neither popular in practice nor concrete in methodology. Especially, the human factors guidelines, which are the most frequent form of human factors engineering in practice, reveal the limitations in their applications. We discuss the limitations and their casual factors found in human factors guidelines in order to lesson the workload of HFE practitioners and to improve the applicability of human factors guidelines. According to the purposes and the phases of HFE for NPPs, more selective items and specified criteria should be prepared carefully in the human factors guidelines for the each HFE applications in practice. These finding on the human factors guidelines can be transferred to the other HFE application field, such as military, aviation, telecommunication, HCI, and product safety

Human factors in nuclear power plants

International Nuclear Information System (INIS)

Swain, A.D.

1981-01-01

This report describes some of the human factors problems in nuclear power plants and the technology that can be employed to reduce those problems. Many of the changes to improve the human factors in existing plants are inexpensive, and the expected gain in human reliability is substantial. The human factors technology is well-established and there are practitioners in most countries that have nuclear power plants. (orig.) [de

Solvent Effects on Nuclear Magnetic Resonance 2J(C,Hf and 1J(C,Hf Spin–Spin Coupling Constants in Acetaldehyde

Directory of Open Access Journals (Sweden)

Angel Esteban

2003-02-01

Full Text Available Abstract: The known solvent dependence of 1J(Cc,Hf and 2J(C1,Hf couplings in acetaldehyde is studied from a theoretical viewpoint based on the density functional theory approach where the dielectric solvent effect is taken into account with the polarizable continuum model. The four terms of scalar couplings, Fermi contact, paramagnetic spin orbital, diamagnetic spin orbital and spin dipolar, are calculated but the solvent effect analysis is restricted to the first term since for both couplings it is by far the dominant contribution. Experimental trends of Δ1J(Cc,Hf and Δ2J(C1,Hf Vs ε (the solvent dielectric constant are correctly reproduced although they are somewhat underestimated. Specific interactions between solute and solvent molecules are studied for dimethylsulfoxide, DMSO, solutions considering two different one-to-one molecular complexes between acetaldehyde and DMSO. They are determined by interactions of type C=O---H---C and S=O---H---C, and the effects of such interactions on 1J(Cc,Hf and 2J(C1,Hf couplings are analyzed. Even though only in a semiquantitative way, it is shown that the effect of such interactions on the solvent effects, of Δ1J(Cc,Hf and Δ2J(C1,Hf, tend to improve the agreement between calculated and experimental values. These results seem to indicate that a continuum dielectric model has not enough flexibility for describing quantitatively solvent effects on spin-spin couplings. Apparently, even for relatively weak hydrogen bonding, the contribution from “direct” interactions is of the same order of magnitude as the “dielectric” effect.

Human factors in nuclear power plants

International Nuclear Information System (INIS)

Pack, R.W.

1978-01-01

The Electric Power Research Institute has started research in human factors in nuclear power plants. One project, completed in March 1977, reviewed human factors problems in operating power plants and produced a report evaluating those problems. A second project developed computer programs for evaluating operator performance on training simulators. A third project is developing and evaluating control-room design approaches. A fourth project is reviewing human factors problems associated with power-plant maintainability and instrumentation and control technician activities. Human factors engineering is an interdisciplinary specialty concerned with influencing the design of equipment systems, facilities, and operational environments to promote safe, efficient, and reliable operator performance. The Electric Power Research Institute (EPRI) has undertaken four projects studying the application of human factors engineering principles to nuclear power plants. (author)

Mixed Messages from Garnet Lu-Hf and Sm-Nd Geochronology

Science.gov (United States)

Vervoort, J. D.; Wang, D.; Johnson, T. A.

2017-12-01

Garnet geochronology provides important information on the timing and conditions of metamorphism. As a major indicator mineral formed during metamorphism, its direct dating can not only help establish the timing of metamorphism, provide the "t" for P-T-t paths, but also, if the dated garnet can be placed in a textural context, can provide information on the timing of deformational features. With advances in chemistry and mass spectrometry, garnet Lu-Hf and Sm-Nd geochronology has become an important geochronological tool and we can now reliably (if not routinely) date a wide variety of garnet compositions formed under diverse conditions. In the course of dating a variety of lithologies using both Lu-Hf and Sm-Nd isotope systems, however, some intriguing results have emerged. Although there are many examples where the Lu-Hf and Sm-Nd systems give the same date within uncertainty, there are also many cases where these systems yield significantly different dates, and the differences between these dates can be considerable—many 10's of Ma of and even 100's of Ma. For example, in garnet-bearing Mesoproterozoic gneisses from across the Blue Ridge Province in Virginia, both Lu-Hf and Sm-Nd analyses (determined on the same solutions) define narrow time spans, but with the Sm-Nd dates systematically younger (for orthogneisses Lu-Hf dates are 1032 to 1019 Ma whereas Sm-Nd dates are 965 to 949 Ma—a difference of 67 to 80 Ma). There are many other examples of systematically younger Sm-Nd garnet dates in both the literature and with our ongoing research. Potential explanations for these differences include: 1) strong partitioning of Lu into garnet during growth yielding ages weighted toward the beginning of growth; 2) faster Lu diffusion from high Lu regions after garnet formation, potentially leading to isochron rotation and anomalously old Lu-Hf dates; and 3) differences in closure temperatures of the two isotope systems. We will review several examples of divergent Lu-Hf

Lu-Hf isotope systematics of fossil biogenic apatite and their effects on geochronology

Science.gov (United States)

Herwartz, Daniel; Münker, Carsten; Tütken, Thomas; Hoffmann, J. Elis; Wittke, Andreas; Barbier, Bruno

2013-01-01

Reliable methods for direct dating of biogenic apatite from pre-Pleistocene fossils are currently not available, and recent attempts using the Lu-Hf decay system yielded highly inaccurate ages for both bones and teeth. The geological processes accounting for this poor accuracy of Lu-Hf chronometry are not yet understood. Here we explore Lu-Hf systematics in fossil bones and teeth in detail, by applying five different sample digestion techniques that are tested on bones and composites of bone and sediment. Our current dataset implies that dissolution methods only slightly affect the resulting Lu-Hf ages, while clear differences between the individual digestion techniques became apparent for element concentrations. By analysing the insoluble leftovers from incomplete sample dissolution, four main reservoirs of Hf in fossil bones were identified: (1) a radiogenic end-member associated with apatite; (2) an unradiogenic end-member represented by the authigenic minerals or the embedding sediment; (3) a highly unradiogenic end-member that can be attributed to detrital zircon; and (4) a moderately soluble phase (probably a Zr(Hf)-phosphate) that yielded very low Lu/Hf but a highly radiogenic Hf isotope composition at the same time. This Zr(Hf)-phase must have been precipitated within the fossil bone sample at a late stage of burial history, thereby incorporating radiogenic 176Hf released from apatite surfaces over geological timescales. A second focus of our study is the effect of different sediment matrices and of crystal size on the preservation of pristine Lu-Hf isotope compositions in bioapatite. Because near-depositional Lu-Hf ages of phosphate fossils have previously been reported for the London Clay (England) and a calcareous marl from Tendaguru (Tanzania), we herein investigate specimens fossilised in carbonate matrices (calcareous marl from Oker, Germany; carbonate concretions from the Santana Formation, Brazil; carbonate from the Eifel, Germany) and argillaceous

Hydrogen fluoride (HF) substance flow analysis for safe and sustainable chemical industry.

Science.gov (United States)

Kim, Junbeum; Hwang, Yongwoo; Yoo, Mijin; Chen, Sha; Lee, Ik-Mo

2017-11-01

In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.

Preparation and enhanced oxidation performance of a Hf-doped single-phase Pt-modified aluminide coating

International Nuclear Information System (INIS)

Yang, Y.F.; Jiang, C.Y.; Yao, H.R.; Bao, Z.B.; Zhu, S.L.; Wang, F.H.

2016-01-01

Graphical abstract: Tiny Hf particles were successfully incorporated into Pt plating via simple electro-plating method. The hafnium particles were either nipped at Pt grain boundaries or wrapped inside Pt grains, and most of them were below 3 μm in size, showing a uniform distribution within the Pt plating. - Highlights: • A Hf-rich belt formed between outer (Ni,Pt)Al and IDZ after aluminisation. • Hf-doped coating showed much decreased mass gain and oxidation rate constant k_p. • Hf-rich belt acted as diffusion barrier by restraining diffusions of Al and W. • Degradation of β was effectively postponed by the unique Hf addition. • Hf-doped coating exhibited lighter oxide scale rumpling tendency. - Abstract: A Hf-doped β-(Ni,Pt)Al coating was prepared by co-deposition of a Pt-Hf composite plating and successive aluminisation. Then, a distinct Hf-rich belt was formed internally between the outer additive (Ni,Pt)Al coating and interdiffusion zone. An isothermal oxidation test at 1100 °C revealed a relatively lower oxidation rate constant and decreased oxide scale rumpling tendency for the Hf-doped coating during which the Hf-rich belt partly acted as an effective diffusion barrier. The unique addition of Hf into a β-(Ni,Pt)Al coating can delay the transitional oxidation period from transient alumina to stable one and postpone the degradation from β to γ'.

Results of Time-of-Flight Neutron Capture Measurements of 176,177,178,179 Hf-enriched and nat Hf samples at 10 m, 30 m and 60 m stations of GELINA

International Nuclear Information System (INIS)

Ware, T.C.; Dean, C.J.; Borella, A.; Kopecky, S.; Moens, A.; Schillebeeckx, P.; Janeva, N.; Moxon, M.C.

2014-04-01

Neutron capture measurements have been performed at the time-offlight facility GELINA to determine neutron resonance parameters for 174,176,177,178,179,180 Hf. In total, 16 distinct experiments were conducted at the 12 m, 28 m and 58 m capture stations using C 6 D 6 detectors with a moderated neutron beam and the accelerator operating at 50 Hz or 800 Hz. Measurements were performed with nat Hf metallic samples and oxide samples enriched in 176 Hf, 177 Hf, 178 Hf and 179 Hf. This report describes the experimental details required to deliver the experimental capture yields to the EXFOR data library which is maintained by the Nuclear Energy Agency of the OECD and the Nuclear Data Section of the IAEA. The experimental conditions and data reduction procedures are described. In addition, the full covariance information based on the AGS concept is given, such that resonance parameters together with their covariances can be derived in a least squares adjustment to the data. (author)

Study of UO{sub 2}F{sub 2} - H{sub 2}O - HF compounds; Etude des composes UO{sub 2}F{sub 2} - H{sub 2}O - HF

Energy Technology Data Exchange (ETDEWEB)

Neveu, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

We study various compounds resulting from the interaction of UO{sub 2}F{sub 2} with H{sub 2}O and HF (gas), and various triple compounds UO{sub 2}F{sub 2} - H{sub 2}O - HF; the conditions of decomposition and the thermodynamic limits of stability are specified. (author) [French] Nous etudions divers composes formes par reaction de UO{sub 2}F{sub 2} avec H{sub 2}O et HF (gaz) et divers composes triples UO{sub 2}F{sub 2} - H{sub 2}O - HF, en essayant de preciser les decompositions et domaines d'exisfence thermodynamiques de ces corps. (auteur)

Specifications for human factors guiding documents

Energy Technology Data Exchange (ETDEWEB)

Rhodes, W; Szlapetis, I; MacGregor, C [Rhodes and Associates Inc., Toronto, ON (Canada)

1995-04-01

This report specifies the content, function and appearance of three proposed human factors guiding documents to be used by the Atomic Energy Control board and its licensees. These three guiding documents, to be developed at a later date, are: (a) Human Factors Process Guide; (b) Human Factors Activities Guide; and (c) Human Factors Design Integration Guide. The specifications were developed by examining the best documents as identified in a previous contract with the AECB (Review of Human Factors Guidelines and Methods by W. Rhodes, I. Szlapetis et al. 1992), and a brief literature review. The best features and content were selected from existing documents and used to develop specifications for the guiding documents. The developer of the actual guides would use these specifications to produce comprehensive and consolidated documents at a later date. (author). 128 ref., 7 figs.

Specifications for human factors guiding documents

International Nuclear Information System (INIS)

Rhodes, W.; Szlapetis, I.; MacGregor, C.

1995-04-01

This report specifies the content, function and appearance of three proposed human factors guiding documents to be used by the Atomic Energy Control board and its licensees. These three guiding documents, to be developed at a later date, are: (a) Human Factors Process Guide; (b) Human Factors Activities Guide; and (c) Human Factors Design Integration Guide. The specifications were developed by examining the best documents as identified in a previous contract with the AECB (Review of Human Factors Guidelines and Methods by W. Rhodes, I. Szlapetis et al. 1992), and a brief literature review. The best features and content were selected from existing documents and used to develop specifications for the guiding documents. The developer of the actual guides would use these specifications to produce comprehensive and consolidated documents at a later date. (author). 128 ref., 7 figs

Luminescence and scintillation properties of Rb2HfCl6 crystals

International Nuclear Information System (INIS)

Saeki, Keiichiro; Wakai, Yuki; Fujimoto, Yutaka; Koshimizu, Masanori; Asai, Keisuke; Yanagida, Takayuki; Nakauchi, Daisuke

2016-01-01

We developed a scintillator based on a Rb 2 HfCl 6 crystal as a ternary halide crystal with intrinsic luminescence. In the photoluminescence spectra, two emission bands are observed at 383 and 434 nm. The 434 nm emission band for Rb 2 HfCl 6 may be attributed to [HfCl 6 ] 2- complex ion or [ZrCl 6 ] 2- impurity, since the Rb 2 HfCl 6 contained Zr as impurity at 0.62 mol %. The radioluminescence band is observed at 420 nm and can be attributed to the same origin as the photoluminescence band at 434 nm. The scintillation decay-time constants were 0.84 and 5.4 μs. The light yield was estimated to be 24,100 photons/MeV. (author)

Atomic scale engineering of HfO{sub 2}-based dielectrics for future DRAM applications

Energy Technology Data Exchange (ETDEWEB)

Dudek, Piotr

2011-02-14

Modern dielectrics in combination with appropriate metal electrodes have a great potential to solve many difficulties associated with continuing miniaturization process in the microelectronic industry. One significant branch of microelectronics incorporates dynamic random access memory (DRAM) market. The DRAM devices scaled for over 35 years starting from 4 kb density to several Gb nowadays. The scaling process led to the dielectric material thickness reduction, resulting in higher leakage current density, and as a consequence higher power consumption. As a possible solution for this problem, alternative dielectric materials with improved electrical and material science parameters were intensively studied by many research groups. The higher dielectric constant allows the use of physically thicker layers with high capacitance but strongly reduced leakage current density. This work focused on deposition and characterization of thin insulating layers. The material engineering process was based on Si cleanroom compatible HfO{sub 2} thin films deposited on TiN metal electrodes. A combined materials science and dielectric characterization study showed that Ba-added HfO{sub 2} (BaHfO{sub 3}) films and Ti-added BaHfO{sub 3} (BaHf{sub 0.5}Ti{sub 0.5}O{sub 3}) layers are promising candidates for future generation of state-of-the-art DRAMs. In especial a strong increase of the dielectric permittivity k was achieved for thin films of cubic BaHfO{sub 3} (k{proportional_to}38) and BaHf{sub 0.5}Ti{sub 0.5}O{sub 3} (k{proportional_to}90) with respect to monoclinic HfO{sub 2} (k{proportional_to}19). Meanwhile the CET values scaled down to 1 nm for BaHfO{sub 3} and {proportional_to}0.8 nm for BaHf{sub 0.5}Ti{sub 0.5}O{sub 3} with respect to HfO{sub 2} (CET=1.5 nm). The Hf{sup 4+} ions substitution in BaHfO{sub 3} by Ti{sup 4+} ions led to a significant decrease of thermal budget from 900 C for BaHfO{sub 3} to 700 C for BaHf{sub 0.5}Ti{sub 0.5}O{sub 3}. Future studies need to focus

The contributions of human factors on human error in Malaysia aviation maintenance industries

Science.gov (United States)

Padil, H.; Said, M. N.; Azizan, A.

2018-05-01

Aviation maintenance is a multitasking activity in which individuals perform varied tasks under constant pressure to meet deadlines as well as challenging work conditions. These situational characteristics combined with human factors can lead to various types of human related errors. The primary objective of this research is to develop a structural relationship model that incorporates human factors, organizational factors, and their impact on human errors in aviation maintenance. Towards that end, a questionnaire was developed which was administered to Malaysian aviation maintenance professionals. Structural Equation Modelling (SEM) approach was used in this study utilizing AMOS software. Results showed that there were a significant relationship of human factors on human errors and were tested in the model. Human factors had a partial effect on organizational factors while organizational factors had a direct and positive impact on human errors. It was also revealed that organizational factors contributed to human errors when coupled with human factors construct. This study has contributed to the advancement of knowledge on human factors effecting safety and has provided guidelines for improving human factors performance relating to aviation maintenance activities and could be used as a reference for improving safety performance in the Malaysian aviation maintenance companies.

Helium implanted AlHf as studied by 181 Ta TDPAC

Indian Academy of Sciences (India)

Measurements on helium implanted sample indicate the binding of helium associated defects by Hf solute clusters. Isochronal annealing measurements indicate the dissociation of the helium implantation induced defects from Hf solute clusters for annealing treatments beyond 650 K. On comparison of the present results ...

Human Factors in Cabin Accident Investigations

Science.gov (United States)

Chute, Rebecca D.; Rosekind, Mark R. (Technical Monitor)

1996-01-01

Human factors has become an integral part of the accident investigation protocol. However, much of the investigative process remains focussed on the flight deck, airframe, and power plant systems. As a consequence, little data has been collected regarding the human factors issues within and involving the cabin during an accident. Therefore, the possibility exists that contributing factors that lie within that domain may be overlooked. The FAA Office of Accident Investigation is sponsoring a two-day workshop on cabin safety accident investigation. This course, within the workshop, will be of two hours duration and will explore relevant areas of human factors research. Specifically, the three areas of discussion are: Information transfer and resource management, fatigue and other physical stressors, and the human/machine interface. Integration of these areas will be accomplished by providing a suggested checklist of specific cabin-related human factors questions for investigators to probe following an accident.

Implementing human factors in clinical practice

Science.gov (United States)

Timmons, Stephen; Baxendale, Bryn; Buttery, Andrew; Miles, Giulia; Roe, Bridget; Browes, Simon

2015-01-01

Objectives To understand whether aviation-derived human factors training is acceptable and useful to healthcare professionals. To understand whether and how healthcare professionals have been able to implement human factors approaches to patient safety in their own area of clinical practice. Methods Qualitative, longitudinal study using semi-structured interviews and focus groups, of a multiprofessional group of UK NHS staff (from the emergency department and operating theatres) who have received aviation-derived human factors training. Results The human factors training was evaluated positively, and thought to be both acceptable and relevant to practice. However, the staff found it harder to implement what they had learned in their own clinical areas, and this was principally attributed to features of the informal organisational cultures. Conclusions In order to successfully apply human factors approaches in hospital, careful consideration needs to be given to the local context and informal culture of clinical practice. PMID:24631959

A Guide to Studying Human Hair Follicle Cycling In Vivo.

Science.gov (United States)

Oh, Ji Won; Kloepper, Jennifer; Langan, Ewan A; Kim, Yongsoo; Yeo, Joongyeub; Kim, Min Ji; Hsi, Tsai-Ching; Rose, Christian; Yoon, Ghil Suk; Lee, Seok-Jong; Seykora, John; Kim, Jung Chul; Sung, Young Kwan; Kim, Moonkyu; Paus, Ralf; Plikus, Maksim V

2016-01-01

Hair follicles (HFs) undergo lifelong cyclical transformations, progressing through stages of rapid growth (anagen), regression (catagen), and relative "quiescence" (telogen). Given that HF cycling abnormalities underlie many human hair growth disorders, the accurate classification of individual cycle stages within skin biopsies is clinically important and essential for hair research. For preclinical human hair research purposes, human scalp skin can be xenografted onto immunocompromised mice to study human HF cycling and manipulate long-lasting anagen in vivo. Although available for mice, a comprehensive guide on how to recognize different human hair cycle stages in vivo is lacking. In this article, we present such a guide, which uses objective, well-defined, and reproducible criteria, and integrates simple morphological indicators with advanced, (immuno)-histochemical markers. This guide also characterizes human HF cycling in xenografts and highlights the utility of this model for in vivo hair research. Detailed schematic drawings and representative micrographs provide examples of how best to identify human HF stages, even in suboptimally sectioned tissue, and practical recommendations are given for designing human-on-mouse hair cycle experiments. Thus, this guide seeks to offer a benchmark for human hair cycle stage classification, for both hair research experts and newcomers to the field. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Oxidation behavior of laser-clad NiAlCrHf alloys

International Nuclear Information System (INIS)

Ribaudo, C.R.

1991-01-01

Laser cladding is the process where a mechanical mixture of powders is rapidly melted and fused to a solid substrate using a CO 2 laser. The effects of laser cladding upon scale retention on NiAlCrHf alloys after cyclic and isothermal exposure to air were investigated. The stress developed in the scale during cooling after exposure was estimated using a thermoelastic model. Additions of up to ∼2 1/2 wt % Hf increasingly promote retention of scales grown at 1,200C. Laser-clad samples containing ∼2 1/2 wt % Hf retained almost-intact scales. The improvement in scale retention is due to improved toughness in scales containing hafnia-rich polycrystallites possibly via microcracking initiated by anisotropic thermal contraction of the hafnia. Laser cladding provides a large concentration of ∼1 μm Hf-rich particles that are precursors of the hafnia in the scale as well as a fine-dendrite spacing that reduced the mean free distance between particles

Effectiveness of human factors simulator

International Nuclear Information System (INIS)

Moragas, F.

2015-01-01

En 2011, ANAV started the exploitation of the Human Factors Simulator installed in TECNATOM Training Center located in L'Hospital de L'Infant Tarragona. AVAN's Strategic Plan includes the Action Plan for the improvement of human behavior. The plan includes improving the efficiency of the efficiency of the human factors simulator. It is proposed to improve the efficiency into two different terms: winning effectiveness in modeling behaviors, and interweaving the activities in the simulator with the actual strategy of promoting Safety culture and human behaviour. (Author)

Chemical states and electronic structure of a HfO(-2)/Ge(001) interface

International Nuclear Information System (INIS)

Seo, Kang-ill; McIntyre, Paul C.; Stanford U., Materials Sci. Dept.; Sun, Shiyu; Lee, Dong-Ick; Pianetta, Piero; SLAC, SSRL; Saraswat, Krishna C.; Stanford U., Elect. Eng. Dept.

2005-01-01

We report the chemical bonding structure and valence band alignment at the HfO 2 /Ge (001) interface by systematically probing various core level spectra as well as valence band spectra using soft x-rays at the Stanford Synchrotron Radiation Laboratory. We investigated the chemical bonding changes as a function of depth through the dielectric stack by taking a series of synchrotron photoemission spectra as we etched through the HfO 2 film using a dilute HF-solution. We found that a very non-stoichiometric GeO x layer exists at the HfO 2 /Ge interface. The valence band spectra near the Fermi level in each different film structure were carefully analyzed, and as a result, the valence band offset between Ge and GeO x was determined to be ΔE v (Ge-GeO x ) = 2.2 ± 0.15 eV, and that between Ge and HfO 2 , ΔE v (Ge-HfO 2 ) = 2.7 ± 0.15 eV

HF-induced airglow at magnetic zenith: theoretical considerations

Directory of Open Access Journals (Sweden)

E. V. Mishin

2005-01-01

Full Text Available Observations of airglow at 630nm (red line and 557.7nm (green line during HF modification experiments at the High Frequency Active Auroral Research Program (HAARP heating facility are analyzed. We propose a theoretical framework for understanding the generation of Langmuir and ion acoustic waves during magnetic zenith injections. We show that observations of HF-induced airglow in an underdense ionosphere as well as a decrease in the height of the emitting volume are consistent with this scenario.

Prediction study of structural, elastic and electronic properties of FeMP (M = Ti, Zr, Hf) compounds

Science.gov (United States)

Tanto, A.; Chihi, T.; Ghebouli, M. A.; Reffas, M.; Fatmi, M.; Ghebouli, B.

2018-06-01

First principles calculations are applied in the study of FeMP (M = Ti, Zr, Hf) compounds. We investigate the structural, elastic, mechanical and electronic properties by combining first-principles calculations with the CASTEP approach. For ideal polycrystalline FeMP (M = Ti, Zr, Hf) the shear modulus, Young's modulus, Poisson's ratio, elastic anisotropy indexes, Pugh's criterion, elastic wave velocities and Debye temperature are also calculated from the single crystal elastic constants. The shear anisotropic factors and anisotropy are obtained from the single crystal elastic constants. The Debye temperature is calculated from the average elastic wave velocity obtained from shear and bulk modulus as well as the integration of elastic wave velocities in different directions of the single crystal.

Interacciones hiperfinas en BaxSr1-xHfO3

Directory of Open Access Journals (Sweden)

López García, A.

1999-10-01

Full Text Available In order to determine the microscopic role of cation A in ABO3 perovskites the hyperfine interaction in the Sr1-xBaxHfO3 system using Perturbed Angular Correlation spectroscopy (PAC is studied. As a previous result the compositions x = 0.50 and 0.25 are shown. The PAC spectra were obtained in the temperature range from 20 to 1000ºC. In both compounds a phase transition to higher symmetry structure was observed at T≈400 and 200ºC, respectively. This structure is proposed to be cubic in both compositions. The results are compared with those obtained in SrHfO3 and BaHfO3.Con el fin de determinar el papel microscópico que juega el catión A en las perovskitas ABO3 se estudia la interacción hiperfina el sistema Sr1-xBaxHfO3 usando la espectroscopia Correlaciones Angulares Perturbadas (PAC en función de la temperatura y la composición. Como resultado previo se muestra en este trabajo, el estudio de las composiciones x = 0.5 y 0.75. Las medidas PAC se realizaron en el intervalo de temperaturas que va desde 20 a 1000ºC. Para x=0.50 y 0.75 se determinó una transición a una fase de mayor simetría a T≈400 y 200ºC, respectivamente. Se propone que esta fase de mayor simetría es cúbica en ambas composiciones. Los resultados obtenidos son comparados con los compuestos puros SrHfO3 y BaHfO3.

HF Parameters of Induction Motor

Directory of Open Access Journals (Sweden)

M. N. Benallal

2017-09-01

Full Text Available This article describes the results of experimental studies of HF input and primary parameters. A simulation model in Matlab SimulinkTM of multiphase windings as ladder circuit of coils is developed. A method for determining the primary parameters of ladder equivalent circuits is presented.

Human Health/Human Factors Considerations in Trans-Lunar Space

Science.gov (United States)

Moore, E. Cherice; Howard, Robert; Mendeck, Gavin

2014-01-01

The human factors insights of how they are incorporated into the vehicle are crucial towards designing and planning the internal designs necessary for future spacecraft and missions. The adjusted mission concept of supporting the Asteroid Redirect Crewed Mission will drive some human factors changes on how the Orion will be used and will be reassessed so as to best contribute to missions success. Recognizing what the human factors and health functional needs are early in the design process and how to integrate them will improve this and future generations of space vehicles to achieve mission success and continue to minimize risks.

Initial search for triggered gamma emission from Hf-178(m2) using the YSU miniball array

Czech Academy of Sciences Publication Activity Database

Carroll, J. J.; Burnett, J.; Drummond, T.; Lepak, J.; Propri, R.; Smith, D.; Karamian, S. A.; Adam, Jindřich; Stedile, F.; Agee, FJ.

2002-01-01

Roč. 143, 1, 2, 3, 4 (2002), s. 37-54 ISSN 0304-3843 Institutional research plan: CEZ:AV0Z1048901 Keywords : triggered gamma emission * Hf-178(m2) * nuclear batteries Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.533, year: 2002

European coordination for coastal HF radar data in EMODnet Physics

Science.gov (United States)

Mader, Julien; Novellino, Antonio; Gorringe, Patrick; Griffa, Annalisa; Schulz-Stellenfleth, Johannes; Montero, Pedro; Montovani, Carlo; Ayensa, Garbi; Vila, Begoña; Rubio, Anna; Sagarminaga, Yolanda

2015-04-01

Historically, joint effort has been put on observing open ocean, organizing, homogenizing, sharing and reinforcing the impact of the acquired information based on one technology: ARGO with profilers Argo floats, EuroSites, ESONET-NoE, FixO3 for deep water platforms, Ferrybox for stations in ships of opportunities, and GROOM for the more recent gliders. This kind of networking creates synergies and makes easier the implementation of this source of data in the European Data exchange services like EMODnet, ROOSs portals, or any applied services in the Blue economy. One main targeted improvement in the second phase of EMODnet projects is the assembling of data along coastline. In that sense, further coordination is recommended between platform operators around a specific technology in order to make easier the implementation of the data in the platforms (4th EuroGOOS DATAMEQ WG). HF radar is today recognized internationally as a cost-effective solution to provide high spatial and temporal resolution current maps (depending on the instrument operation frequency, covering from a few kilometres offshore up to 200 km) that are needed for many applications for issues related to ocean surface drift or sea state characterization. Significant heterogeneity still exists in Europe concerning technological configurations, data processing, quality standards and data availability. This makes more difficult the development of a significant network for achieving the needed accessibility to HF Radar data for a pan European use. EuroGOOS took the initiative to lead and coordinate activities within the various observation platforms by establishing a number of Ocean Observing Task Teams such as HF-Radars. The purpose is to coordinate and join the technological, scientific and operational HF radar communities at European level. The goal of the group is on the harmonization of systems requirements, systems design, data quality, improvement and proof of the readiness and standardization of

Densification and properties of HfB2 based materials

International Nuclear Information System (INIS)

Sonber, J.K.; Ch Murthy, T.S.R.; Bedse, R.D.; Subramanian, C.; Kumar, Sunil; Fotedar, R.K.; Krishnamurthy, N.; Suri, A.K.

2011-01-01

This paper presents the results of investigation carried out on densification and properties of HfB 2 based materials. Densification study of HfB 2 with and without sinter additive was carried out by hot pressing. TiSi 2 and CrSi 2 were used as sinter additive. Monolithic HfB 2 was densified to only 80%ρ th at 1850 deg C with a pressure of 35 MPa. Addition of 10 wt% TiSi 2 resulted in a density of 95% TD at a relatively low temperature of 1650 deg C and a low pressure of 20 MPa. Addition of 10% CrSi 2 resulted in a density of 99% TD at the same operating conditions. All the samples were characterized by SEM/EDS and mechanical property measurement. (author)

Sr-Nd-Hf isotopic fingerprinting of transatlantic dust derived from North Africa

Science.gov (United States)

Zhao, Wancang; Balsam, William; Williams, Earle; Long, Xiaoyong; Ji, Junfeng

2018-03-01

Long-range transport of African dust plays an important role in understanding dust-climate relationships including dust source areas, dust pathways and associated atmospheric and/or oceanic processes. Clay-sized Sr-Nd-Hf isotopic compositions can be used as geochemical fingerprints to constrain dust provenance and the pathways of long-range transported mineral dust. We investigated the clay-sized Sr-Nd-Hf isotopic composition of surface samples along four transects bordering the Sahara Desert. The transects are from Mali, Niger/Benin/Togo, Egypt and Morocco. Our results show that the Mali transect on the West African Craton (WAC) produces lower εNd (εNd-mean = -16.38) and εHf (εHf-mean = -9.59) values than the other three transects. The Egyptian transect exhibits the lowest 87Sr/86Sr ratios (87Sr/86Srmean = 0.709842), the highest εHf (εHf-mean = -0.34) and εNd values of the four transects. Comparison of the clay-sized Sr-Nd-Hf isotopic values from our North African samples to transatlantic African dust collected in Barbados demonstrates that the dust's provenance is primarily the western Sahel and Sahara as well as the central Sahel. Summer emission dust is derived mainly from the western Sahel and Sahara regions. The source of transatlantic dust in spring and autumn is more varied than in the summer and includes dust not only from western areas, but also south central areas. Comparison of the Sr-Nd-Hf isotopic fingerprints between the source and sink of transatlantic dust also suggests that a northwestward shift in dust source occurs from the winter, through the spring and into the summer. The isotopic data we develop here provide another tool for discriminating changes in dust archives resulting from paleoenvironmental evolution of source regions.

A novel method for the evaluation of polarization and hemisphere coverage of HF radio noise measurement antennas

NARCIS (Netherlands)

Witvliet, Ben A.; van Maanen, Erik; Bentum, Mark J.; Slump, Cornelis H.; Schiphorst, Roel

2015-01-01

In HF (3-30 MHz) communications the ambient electromagnetic background noise or 'radio noise' generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the

Temporal evolution of the HF-enhanced plasma line in sporadic E

International Nuclear Information System (INIS)

Djuth, F.T.; Gonzales, C.A.

1988-01-01

The high-power, high-frequency (HF) facility at Arecibo, Puerto Rico, has been used to study the excitation of Langmuir waves in mid-latitude sporadic E. Measurements of the temporal evolution of so-called HF-enhanced plasma line (HFPL) were made using the Arecibo 430-MHz radar. After HF turn-on in the plasma the HFPL exhibits a rapid growth phase followed by a quick overshoot. During periods of strong HFPL excitation the e-folding growth time of the HFPL power is typically approx-lt 20 μs, and the total overshoot period is ∼1 ms. On the basis of the current observations, mode conversion of the HF wave into Langmuir waves near HF reflection appears to be a promising mechanism for the production of Langmuir waves in sporadic E. Caviton formation at the critical layer is expected to accompany this process, and there is some evidence that the 430-MHz radar is probing the plasma in a region where density cavities of this nature form. While no specific explanation is offered for the HFPL overshoot, it appears that this phenomenon is fundamental to the Langmuir wave excitation process

DIRECT DETERMINATION OF THE HF/H{sub 2} ABUNDANCE RATIO IN INTERSTELLAR GAS

Energy Technology Data Exchange (ETDEWEB)

Indriolo, Nick; Neufeld, D. A. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Seifahrt, A. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Richter, M. J. [Department of Physics, University of California Davis, Davis, CA 95616 (United States)

2013-02-20

We report the first detection of the v = 1-0, R(0) ro-vibrational transition of HF at 2.499385 {mu}m arising from interstellar gas. The line is seen in absorption toward three background sources-HD 154368, Elias 29, and AFGL 2136 IRS 1-all of which have reported H{sub 2} column densities determined from observations of H{sub 2}. This allows for the first direct determination of the HF/H{sub 2} abundance ratio. We find values of N(HF)/N(H{sub 2}) = 1.15 Multiplication-Sign 10{sup -8} and 0.69 Multiplication-Sign 10{sup -8} for HD 154368 and Elias 29, respectively. The sight line toward AFGL 2136 IRS 1 also shows absorption from the v = 1-0, R(1) transition of HF, indicating warm, dense (n {sub H} {approx}> 10{sup 9} cm{sup -3}) gas, likely very close to the central protostar. Ascribing portions of the HF absorption to warm and cold gas, we find N(HF)/N(H{sub 2}) = (1.7-2.9) Multiplication-Sign 10{sup -8} and (0.33-0.58) Multiplication-Sign 10{sup -8} for the two components, respectively. Except for the warm component toward AFGL 2136 IRS 1, all observed HF/H{sub 2} ratios are well below N(HF)/N(H{sub 2}) = 3.6 Multiplication-Sign 10{sup -8}, the value predicted if nearly all gas phase fluorine is in the form of HF. Models of fluorine chemistry that account for depletion onto grains are able to reproduce the results toward HD 154368, but not in the cold, dense gas toward AFGL 2136 IRS 1 and Elias 29. Most likely, some combinations of simplifying assumptions made in the chemical models are responsible for these discrepancies.

Ergonomic and macro ergonomic factors of the 'Ukrytie' shelter personnel safe activity

International Nuclear Information System (INIS)

Zhuravlev, G.E.; Kupnyj, V.I.; Danilov, V.M.; Vtornikov, V.E.

1999-01-01

Four actions are planned based upon this preliminary analysis of Human Factors technology applied to the Chernobyl Shelter activities, namely: 1. Provide expertise to and participate in all projects regarding the Shelter's future. 2. Conduct a detailed on-site survey of the current Shelter's situation. 3. Organize a business game (brain-storming) to shape the system of the Shelter's HF problems

Human Factors Laboratory

Data.gov (United States)

Federal Laboratory Consortium — Purpose: The purpose of the Human Factors Laboratory is to further the understanding of highway user needs so that those needs can be incorporated in roadway design,...

New three-phase ac-ac converter incorporating three-phase boost integrated ZVT bridge and single-phase HF link

International Nuclear Information System (INIS)

Abdelhamid, Tamer H.; Sabzali, Ahmad J.

2008-01-01

This paper presents a new zero voltage transition (ZVT), power factor corrected three phase ac-ac converter with single phase high frequency (HF) link. It is a two stage converter; the first stage is a boost integrated bridge converter (combination of a 3 ph boost converter and a bridge converter) operated at fixed frequency and that operates in two modes at ZVT for all switches and establishes a 1 ph square wave HF link. The second stage is a bi-directional pulse width modulation (PWM) 3 ph bridge that converts the 1 ph HF link to a 3 ph voltage using a novel switching strategy. The converter modes of operation and key equations are outlined. Simulation of the overall system is conducted using Simulink. The switching strategy and its corresponding control circuit are clearly described. Experimental verification of the simulation is conducted for a prototype of 100 V, 500 W at 10 kHz link frequency

Implementing human factors in clinical practice.

Science.gov (United States)

Timmons, Stephen; Baxendale, Bryn; Buttery, Andrew; Miles, Giulia; Roe, Bridget; Browes, Simon

2015-05-01

To understand whether aviation-derived human factors training is acceptable and useful to healthcare professionals. To understand whether and how healthcare professionals have been able to implement human factors approaches to patient safety in their own area of clinical practice. Qualitative, longitudinal study using semi-structured interviews and focus groups, of a multiprofessional group of UK NHS staff (from the emergency department and operating theatres) who have received aviation-derived human factors training. The human factors training was evaluated positively, and thought to be both acceptable and relevant to practice. However, the staff found it harder to implement what they had learned in their own clinical areas, and this was principally attributed to features of the informal organisational cultures. In order to successfully apply human factors approaches in hospital, careful consideration needs to be given to the local context and informal culture of clinical practice. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Formation of Al2O3-HfO2 Eutectic EBC Film on Silicon Carbide Substrate

Directory of Open Access Journals (Sweden)

Kyosuke Seya

2015-01-01

Full Text Available The formation mechanism of Al2O3-HfO2 eutectic structure, the preparation method, and the formation mechanism of the eutectic EBC layer on the silicon carbide substrate are summarized. Al2O3-HfO2 eutectic EBC film is prepared by optical zone melting method on the silicon carbide substrate. At high temperature, a small amount of silicon carbide decomposed into silicon and carbon. The components of Al2O3 and HfO2 in molten phase also react with the free carbon. The Al2O3 phase reacts with free carbon and vapor species of AlO phase is formed. The composition of the molten phase becomes HfO2 rich from the eutectic composition. HfO2 phase also reacts with the free carbon and HfC phase is formed on the silicon carbide substrate; then a high density intermediate layer is formed. The adhesion between the intermediate layer and the substrate is excellent by an anchor effect. When the solidification process finished before all of HfO2 phase is reduced to HfC phase, HfC-HfO2 functionally graded layer is formed on the silicon carbide substrate and the Al2O3-HfO2 eutectic structure grows from the top of the intermediate layer.

Temperature dependent electrical characterisation of Pt/HfO{sub 2}/n-GaN metal-insulator-semiconductor (MIS) Schottky diodes

Energy Technology Data Exchange (ETDEWEB)

Shetty, Arjun, E-mail: arjun@ece.iisc.ernet.in; Vinoy, K. J. [Electrical Communication Engineering, Indian Institute of Science, Bangalore, India 560012 (India); Roul, Basanta; Mukundan, Shruti; Mohan, Lokesh; Chandan, Greeshma; Krupanidhi, S. B. [Materials Research Centre, Indian Institute of Science, Bangalore, India 560012 (India)

2015-09-15

This paper reports an improvement in Pt/n-GaN metal-semiconductor (MS) Schottky diode characteristics by the introduction of a layer of HfO{sub 2} (5 nm) between the metal and semiconductor interface. The resulting Pt/HfO{sub 2}/n-GaN metal-insulator-semiconductor (MIS) Schottky diode showed an increase in rectification ratio from 35.9 to 98.9(@ 2V), increase in barrier height (0.52 eV to 0.63eV) and a reduction in ideality factor (2.1 to 1.3) as compared to the MS Schottky. Epitaxial n-type GaN films of thickness 300nm were grown using plasma assisted molecular beam epitaxy (PAMBE). The crystalline and optical qualities of the films were confirmed using high resolution X-ray diffraction and photoluminescence measurements. Metal-semiconductor (Pt/n-GaN) and metal-insulator-semiconductor (Pt/HfO{sub 2}/n-GaN) Schottky diodes were fabricated. To gain further understanding of the Pt/HfO{sub 2}/GaN interface, I-V characterisation was carried out on the MIS Schottky diode over a temperature range of 150 K to 370 K. The barrier height was found to increase (0.3 eV to 0.79 eV) and the ideality factor decreased (3.6 to 1.2) with increase in temperature from 150 K to 370 K. This temperature dependence was attributed to the inhomogeneous nature of the contact and the explanation was validated by fitting the experimental data into a Gaussian distribution of barrier heights.

Human factors in nuclear power plant operations

International Nuclear Information System (INIS)

Swain, A.D.

1980-08-01

This report describes some of the human factors problems in nuclear power plants and the technology that can be employed to reduce those problems. Many of the changes to improve the human factors in existing plants are inexpensive, and the expected gain in human reliability is substantial. The human factors technology is well-established and there are practitioners in most countries that have nuclear power plants

EURObservational Research Programme: the Heart Failure Pilot Survey (ESC-HF Pilot)

DEFF Research Database (Denmark)

Maggioni, Aldo P; Dahlström, Ulf; Filippatos, Gerasimos

2010-01-01

The primary objective of the new ESC-HF Pilot Survey was to describe the clinical epidemiology of outpatients and inpatients with heart failure (HF) and the diagnostic/therapeutic processes applied across 12 participating European countries. This pilot study was specifically aimed at validating...

Human factors methods in DOE nuclear facilities

International Nuclear Information System (INIS)

Bennett, C.T.; Banks, W.W.; Waters, R.J.

1993-01-01

The US Department of Energy (DOE) is in the process of developing a series of guidelines for the use of human factors standards, procedures, and methods to be used in nuclear facilities. This paper discusses the philosophy and process being used to develop a DOE human factors methods handbook to be used during the design cycle. The following sections will discuss: (1) basic justification for the project; (2) human factors design objectives and goals; and (3) role of human factors engineering (HFE) in the design cycle

Preparation and study of the critical-mass-free plutonium ceramics with neutron poisons Hf, Gd and Li

International Nuclear Information System (INIS)

Timoefeeva, L.F.; Orlov, V.K.; Malyukov, E.E.; Molomin, V.I.; Zhmak, V.A.; Semova, E.A.; Shishkov, N.V.; Nadykto, B.A.

2002-01-01

Powder sintering was used to produce homogeneous type oxide ceramics of Pu with Hf, Gd and Li 6 . In all the ceramics, there is the number of neutron poison (Hf, Gd and Li) atoms per plutonium atom needed, according to the physical calculation, for them to be free of critical mass. PuO 2 stabilizers high-temperature modifications of cubic HfO 2 or hexagonal Gd 2 O 3 , however, at the ratio given by the physical calculation, the plutonium is insufficient for their full stabilization. Addition of yttrium oxide as an additive stabilizing the fcc phase of HfO 2 resulted in cubic solid solution (Pu, Hf, Y)O 2-x . Pu/Li/Hf and Pu/Li/Si ceramics produced by sintering of PuO 2 and compound Li 2 HfO 3 or 6 Li 4 SiO 4 powders is characterized with presence of two phases. The method of differential thermal analysis demonstrated the phase stability of (Pu-Hf, Pu-Gd, Pu-Li-Hf) oxide ceramics in the 20-1500degC temperature range. Ceramic (Pu/Li/Si) has several endothermal effects. Tests in boiling water solutions of various composition suggest that the specimens of Pu, Hf oxides and ternary oxides (Pu, Hf, Y)O 2 are less stable in weakly acidic media than in weakly alkaline medium and distilled water. The obtained results were used as a basis to estimate the assumed solid solution region boundaries for binary Hf, Pu and ternary Hf, Pu, Y oxides on the side of HfO 2 . (author)

Mechanical properties of ultra-thin HfO2 films studied by nano scratches tests

International Nuclear Information System (INIS)

Fu, Wei-En; Chang, Yong-Qing; Chang, Chia-Wei; Yao, Chih-Kai; Liao, Jiunn-Der

2013-01-01

10-nm-thick atomic layer deposited HfO 2 films were characterized in terms of wear resistance and indentation hardness to investigate the thermal annealing induced impacts on mechanical properties. The wear resistance of ultra-thin films at low loads was characterized using nano-scratch tests with an atomic force microscope. The depth of the nano-scratches decreases with increasing annealing temperature, indicating that the hardness of the annealed films increases with the annealing temperatures. Surface nanoindentation was also performed to confirm the nanoscratch test results. The hardness variation of the annealed films is due to the generation of HfSi x O y induced by the thermal annealing. X-ray photoelectron spectroscopy measurements proved that the hardness of formed HfSi x O y with increasing annealing temperatures. The existence of HfSi x O y broadens the interface, and causes the increase of the interfacial layer thickness. As a result, the surface hardness increases with the increasing HfSi x O y induced by the thermal annealing. - Highlights: ► Mechanical properties of HfO 2 films were assessed by nano-scratch and indentation. ► Scratch depth of HfO 2 films decreased with the increase of annealing temperatures. ► Nano-hardness of HfO 2 films increased with the increase of annealing temperatures

Integrating human factors into process hazard analysis

International Nuclear Information System (INIS)

Kariuki, S.G.; Loewe, K.

2007-01-01

A comprehensive process hazard analysis (PHA) needs to address human factors. This paper describes an approach that systematically identifies human error in process design and the human factors that influence its production and propagation. It is deductive in nature and therefore considers human error as a top event. The combinations of different factors that may lead to this top event are analysed. It is qualitative in nature and is used in combination with other PHA methods. The method has an advantage because it does not look at the operator error as the sole contributor to the human failure within a system but a combination of all underlying factors

Comparing LCZ696 with enalapril according to baseline risk using the MAGGIC and EMPHASIS-HF risk scores: an analysis of mortality and morbidity in PARADIGM-HF.

Science.gov (United States)

Simpson, Joanne; Jhund, Pardeep S; Silva Cardoso, Jose; Martinez, Felipe; Mosterd, Arend; Ramires, Felix; Rizkala, Adel R; Senni, Michele; Squire, Iain; Gong, Jianjian; Lefkowitz, Martin P; Shi, Victor C; Desai, Akshay S; Rouleau, Jean L; Swedberg, Karl; Zile, Michael R; McMurray, John J V; Packer, Milton; Solomon, Scott D

2015-11-10

Although most patients in the PARADIGM-HF (Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) trial had mild symptoms, there is a poor correlation between reported functional limitation and prognosis in heart failure. The aim of this study was to examine the spectrum of risk in PARADIGM-HF and the effect of LCZ696 across that spectrum. This study analyzed rates of the primary composite outcome of cardiovascular death or heart failure hospitalization, its components, and all-cause mortality using the MAGGIC (Meta-Analysis Global Group in Chronic Heart Failure) and EMPHASIS-HF (Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure) risk scores to categorize patients. The authors determined whether risk, on the basis of these scores, modified the treatment effect of LCZ696. The complete MAGGIC risk score was available for 8,375 of the 8,399 patients in PARADIGM-HF. The median MAGGIC score was 20 (IQR: 16 to 24). An increase of 1 point was associated with a 6% increased risk for the primary endpoint (p PARADIGM-HF patients had mild symptoms, many were at high risk for adverse outcomes and obtained a large absolute benefit from LCZ696, compared with enalapril, over a relatively short treatment period. LCZ696's benefit was consistent across the spectrum of risk. (PARADIGM-HF trial [Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure]; NCT01035255). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Introduction to human factors

International Nuclear Information System (INIS)

Winters, J.M.

1988-03-01

Some background is given on the field of human factors. The nature of problems with current human/computer interfaces is discussed, some costs are identified, ideal attributes of graceful system interfaces are outlined, and some reasons are indicated why it's not easy to fix the problems

Human factors influencing decision making

OpenAIRE

Jacobs, Patricia A.

1998-01-01

This report supplies references and comments on literature that identifies human factors influencing decision making, particularly military decision making. The literature has been classified as follows (the classes are not mutually exclusive): features of human information processing; decision making models which are not mathematical models but rather are descriptive; non- personality factors influencing decision making; national characteristics influencing decision makin...

EURObservational Research Programme : The Heart Failure Pilot Survey (ESC-HF Pilot)

NARCIS (Netherlands)

Maggioni, Aldo P.; Dahlstrom, Ulf; Filippatos, Gerasimos; Chioncel, Ovidiu; Crespo Leiro, Marisa; Drozdz, Jaroslaw; Fruhwald, Friedrich; Gullestad, Lars; Logeart, Damien; Metra, Marco; Parissis, John; Persson, Hans; Ponikowski, Piotr; Rauchhaus, Mathias; Voors, Adriaan A.; Nielsen, Olav Wendelboe; Zannad, Faiez; Tavazzi, Luigi

2010-01-01

The primary objective of the new ESC-HF Pilot Survey was to describe the clinical epidemiology of outpatients and inpatients with heart failure (HF) and the diagnostic/therapeutic processes applied across 12 participating European countries. This pilot study was specifically aimed at validating the

Absolute El Transition Probabilities in the Deformed Nuclei 177Yb and Hf179

International Nuclear Information System (INIS)

Malmskog, Sven G.

1964-08-01

The absolute E1-transition probabilities have been measured for two 7/2 - (514) levels populated from the short-lived isomers 177m Yb (6.4 sec) and 179m Hf (18.6 sec), a delayed coincidence set up being used for the purpose. This gave a half life of T 1/2 = (4.48 ± 0.08)x10 -9 sec for the 104 keV level in 177 Yb and T 1/2 = (1.86 ± 0.05)x10 -9 sec for the 217 keV level in 179 Hf. The result has been compared with the calculations made by Nilsson. The effect of the pairing correlation has also been taken into account. An agreement with the experimental values to within a factor of three is obtained. An extrapolated estimate of the half life for the 408.9 keV 7/2 - (514) level in 181 W gives 3x10 -11 sec

Suppression of interfacial reaction for HfO2 on silicon by pre-CF4 plasma treatment

International Nuclear Information System (INIS)

Lai, C.S.; Wu, W.C.; Chao, T.S.; Chen, J.H.; Wang, J.C.; Tay, L.-L.; Rowell, Nelson

2006-01-01

In this letter, the effects of pre-CF 4 plasma treatment on Si for sputtered HfO 2 gate dielectrics are investigated. The significant fluorine was incorporated at the HfO 2 /Si substrate interface for a sample with the CF 4 plasma pretreatment. The Hf silicide was suppressed and Hf-F bonding was observed for the CF 4 plasma pretreated sample. Compared with the as-deposited sample, the effective oxide thickness was much reduced for the pre-CF 4 plasma treated sample due to the elimination of the interfacial layer between HfO 2 and Si substrate. These improved characteristics of the HfO 2 gate dielectrics can be explained in terms of the fluorine atoms blocking oxygen diffusion through the HfO 2 film into the Si substrate

Human factors in safety and business management.

Science.gov (United States)

Vogt, Joachim; Leonhardt, Jorg; Koper, Birgit; Pennig, Stefan

2010-02-01

Human factors in safety is concerned with all those factors that influence people and their behaviour in safety-critical situations. In aviation these are, for example, environmental factors in the cockpit, organisational factors such as shift work, human characteristics such as ability and motivation of staff. Careful consideration of human factors is necessary to improve health and safety at work by optimising the interaction of humans with their technical and social (team, supervisor) work environment. This provides considerable benefits for business by increasing efficiency and by preventing incidents/accidents. The aim of this paper is to suggest management tools for this purpose. Management tools such as balanced scorecards (BSC) are widespread instruments and also well known in aviation organisations. Only a few aviation organisations utilise management tools for human factors although they are the most important conditions in the safety management systems of aviation organisations. One reason for this is that human factors are difficult to measure and therefore also difficult to manage. Studies in other domains, such as workplace health promotion, indicate that BSC-based tools are useful for human factor management. Their mission is to develop a set of indicators that are sensitive to organisational performance and help identify driving forces as well as bottlenecks. Another tool presented in this paper is the Human Resources Performance Model (HPM). HPM facilitates the integrative assessment of human factors programmes on the basis of a systematic performance analysis of the whole system. Cause-effect relationships between system elements are defined in process models in a first step and validated empirically in a second step. Thus, a specific representation of the performance processes is developed, which ranges from individual behaviour to system performance. HPM is more analytic than BSC-based tools because HPM also asks why a certain factor is

Probing the effect of neutron excess on the dynamics of Hf compound system

Science.gov (United States)

Sharma, Ishita; Kumar, Raj; Sharma, Manoj K.

2018-05-01

The reaction dynamics of 170Hf* and 174Hf* compound systems formed in 46,50Ti +124Sn reactions have been analyzed within the framework of Dynamical Cluster-decay Model (DCM) over an energy range of Ec.m.=115-156 MeV. The experimental data of fusion evaporation cross sections for 170,174Hf* systems is successfully addressed by optimizing the value of neck length ΔR. It is to be noted that calculations are performed by taking quadrupole deformations β2 with the optimum orientation of decaying fragments. Here, the effect of neutron excess has been examined on the structural properties of decaying fragments via fragmentation potential and preformation probability. The observation depicts that the isotopic effect prevails at fission region and as we move from lighter nucleus i.e. 170Hf* to heavier nucleus i.e. 174Hf*, the heavy mass fragments (HMF) start contributing along with fission fragments which are equally evident for 170Hf* as well. The ΔR values so obtained are compared at center of mass-energies which consequently provides information regarding the relative time scale of decaying fragments.

Prognostic factors of hydrops fetalis with pleural effusion.

Science.gov (United States)

Nakayama, Atsushi; Oshiro, Makoto; Yamada, Yasumasa; Hattori, Tetsuo; Wakano, Yasuhiro; Hayashi, Seiji; Kokubo, Minoru; Takemoto, Koji; Honda, Shigeru; Ieda, Kuniko; Yamamoto, Hikaru; Kouwaki, Masanori; Yokoi, Kyoko; Shinohara, Osamu; Kato, Takenori; Miyata, Masafumi; Tanaka, Taihei; Hayakawa, Masahiro

2017-10-01

Hydrops fetalis (HF) has a low survival rate, particularly in the case of preterm birth. In addition, the severity index of HF has not been fully investigated yet. The aim of this study was to clarify the prognostic factors of HF with pleural effusion. All live-born HF patients with pleural effusion, except for chromosomal abnormality or complex congenital heart disease, born from 2009 to 2013 in Aichi Prefecture in Japan were included. Prenatal, perinatal, and postnatal information was obtained from the medical records and was retrospectively analyzed. Forty-one HF patients with pleural effusion were included, and 28 patients (68%) survived. On multivariate logistic stepwise analysis, gestational birth week (OR, 0.71; 95% CI: 0.52-0.96, P = 0.027) and standard deviation (SD) score of the birthweight (OR, 1.74; 95% CI: 1.01-2.99, P = 0.045) were significant factors for postnatal death. All patients with both ≥32 gestational weeks and pleural effusion. © 2017 Japan Pediatric Society.

Centrifugal stretching along the ground state band of 168Hf

International Nuclear Information System (INIS)

Costin, A.; Pietralla, N.; Reese, M.; Moeller, O.; Ai, H.; Casten, R. F.; Heinz, A.; McCutchan, E. A.; Meyer, D. A.; Qian, J.; Werner, V.; Dusling, K.; Fitzpatrick, C. R.; Guerdal, G.; Petkov, P.; Rainovski, G.

2009-01-01

The lifetimes of the J π =4 + , 6 + , 8 + , and 10 + levels along the ground state band in 168 Hf were measured by means of the recoil distance Doppler shift (RDDS) method using the New Yale Plunger Device (NYPD) and the SPEEDY detection array at Wright Nuclear Structure Laboratory of Yale University. Excited states in 168 Hf were populated using the 124 Sn( 48 Ti,4n) fusion evaporation reaction. The new lifetime values are sufficiently precise to clearly prove the increase of quadrupole deformation as a function of angular momentum in the deformed nucleus 168 Hf. The data agree with the predictions from the geometrical confined β-soft (CBS) rotor model that involves centrifugal stretching in a soft potential

Effects of C and Hf concentration on phase relations and microstructure of a wrought powder-metallurgy superalloy

Science.gov (United States)

Miner, R. V., Jr.

1977-01-01

NASA IIB-11, a candidate alloy for advanced temperature turbine engine disks, and four modifications with varying C and Hf concentrations were produced from prealloyed powders. Several notable effects of C and Hf concentration in the alloys were observed. Both the amount of the gamma-prime phase and its solvus temperature increased with decreasing C, but only the gamma-prime solvus was affected by Hf, increasing with increasing Hf. Hf also promoted a cellular gamma-prime precipitation. Hf was, however, about equally distributed between gamma-prime and gamma. Hf and C both affected the carbides formed. Increasing both promoted formation of an MC relative to that of an M6C.

HF propagation results from the Metal Oxide Space Cloud (MOSC) experiment

Science.gov (United States)

Joshi, Dev; Groves, Keith M.; McNeil, William; Carrano, Charles; Caton, Ronald G.; Parris, Richard T.; Pederson, Todd R.; Cannon, Paul S.; Angling, Matthew; Jackson-Booth, Natasha

2017-06-01

With support from the NASA sounding rocket program, the Air Force Research Laboratory launched two sounding rockets in the Kwajalein Atoll, Marshall Islands in May 2013 known as the Metal Oxide Space Cloud experiment. The rockets released samarium metal vapor at preselected altitudes in the lower F region that ionized forming a plasma cloud. Data from Advanced Research Project Agency Long-range Tracking and Identification Radar incoherent scatter radar and high-frequency (HF) radio links have been analyzed to understand the impacts of the artificial ionization on radio wave propagation. The HF radio wave ray-tracing toolbox PHaRLAP along with ionospheric models constrained by electron density profiles measured with the ALTAIR radar have been used to successfully model the effects of the cloud on HF propagation. Up to three new propagation paths were created by the artificial plasma injections. Observations and modeling confirm that the small amounts of ionized material injected in the lower F region resulted in significant changes to the natural HF propagation environment.

Reducing the stoichiometric excess of HF in the hydrofluorination of UO2

International Nuclear Information System (INIS)

Zhao Jun; Qiu Lufu; Zhong Xing; Xu Heqing

1989-11-01

In a fluidized bed, UO 2 obtained from the decomposition-reduction of AUC (Ammonium Uranyl Carbonate) was fed to absorb HF remaining in the exhaust gas of UF 4 production process. In the case of 60% conversion of UO 2 and the reaction temperature in the region of 300 deg C, HF remaining in the exhaust gas in absorbing fluidized bed was less than 7 ∼ 8% (w/w), i.e. apparent stoichiometric excess of HF had reduced to 0% more or less. Hence, with the high hydrofluorination reactivity of UO 2 obtained from the decomposition-reduction of AUC, it is possible to reduce evidently the stoichiometric excess of HF in the hydrofluorination process by two fluidized beds in series in which solids move against the gas flow

Human factor problem in nuclear power generation

International Nuclear Information System (INIS)

Yoshino, Kenji; Fujimoto, Junzo

1999-01-01

Since a nuclear power plant accident at Threemile Island in U.S.A. occurred in March, 1979, twenty years have passed. After the accident, the human factor problem became focussed in nuclear power, to succeed its research at present. For direct reason of human error, most of factors at individual level or work operation level are often listed at their center. Then, it is natural that studies on design of a machine or apparatus suitable for various human functions and abilities and on improvement of relationship between 'human being and machine' and 'human being and working environment' are important in future. Here was, as first, described on outlines of the human factor problem in a nuclear power plant developed at a chance of past important accident, and then was described on educational training for its countermeasure. At last, some concrete researching results obtained by human factor research were introduced. (G.K.)

HF-DLLME

OpenAIRE

Simão, Vanessa

2015-01-01

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2015. Neste trabalho foi proposto, pela primeira vez, a combinação simultânea das técnicas de microextração em fase líquida suportada em fibra oca (HF-LPME) e microextração líquido-líquido dispersiva (DLLME) para aplicação em amostras líquidas. Dois estudos foram desenvolvidos utilizando a metodologia proposta, a qua...

Phase transformation and precipitation in aged Ti-Ni-Hf high-temperature shape memory alloys

International Nuclear Information System (INIS)

Meng, X.L.; Cai, W.; Zheng, Y.F.; Zhao, L.C.

2006-01-01

More attention has been paid to ternary Ti-Ni-Hf high-temperature shape memory alloys (SMAs) due to their high phase transformation temperatures, good thermal stability and low cost. However, the Ti-Ni-Hf alloys have been found to have low ductility and only about 3% shape memory effect and these have hampered their applications. It is well known that there are three methods to improve the shape memory properties of high-temperature SMAs: (a) cold rolling + annealing; (b) adding another element to the alloy; (c) aging. These methods are not suitable to improve the properties of Ti-Ni-Hf alloys. In this paper, a method of conditioning Ni-rich Ti-Ni-Hf alloys as high-temperature SMAs by aging is presented. For Ni-rich Ti 80-x Ni x Hf 20 alloys (numbers indicate at.%) the phase transformation temperatures are on average increased by more than 100 K by aging at 823 K for 2 h. Especially for those alloys with Ni contents less than 50.6 at.%, the martensitic transformation start temperatures (M s ) are higher than 473 K after aging. Transmission electron microscopy shows the presence of (Ti + Hf) 3 Ni 4 precipitates after aging. Compared with the precipitation of Ti 3 Ni 4 particles in Ni-rich Ti-Ni alloys, the precipitation of (Ti + Hf) 3 Ni 4 particles in Ni-rich Ti-Ni-Hf alloys needs higher temperatures and longer times

Research on disaster prevention by human factor

Energy Technology Data Exchange (ETDEWEB)

Kim, Bok Youn; Kang, Chang Hee; Kang, Sun Duck; Jo, Young Do [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1998-12-01

Mining, by its very nature, requires workers and technology to function in an unpredictable environment that can not easily be engineered to accommodate human factors. Miners' physical and cognitive capabilities are sometimes stretched to the point that 'human error' in performance result. Mine safety researchers estimate that 50-85% of all mining injuries are due, in large part, to human error. Further research suggests that the primary causes of these errors in performance lie outside the individual and can be minimized by improvements in equipment design, work environments, work procedures and training. The human factors research is providing the science needed to determine which aspects of the mining environment can be made more worker-friendly and how miners can work more safely in environments that can not be improved. Underground mines have long been recognized as an innately hazardous and physically demanding work environment. Recently, mining is becoming a more complicated process as more sophisticated technologies are introduced. The more complicated or difficult the tasks to be performed, the more critical it is to have a systematic understanding of the humans, the technology, the environments, and how they interact. Human factors is a key component in solving most of today's mine safety and health problems. Human factors research primarily centered around solving problems in the following four areas: 1) How mining methods and equipment affect safety, 2) Evaluating the fit between miner's physical capabilities and the demands of their job, 3) Improving miner's ability to perceive and react to hazards, 4) Understanding how organizational and managerial variables influence safety. Human factor research was begun during the World war II. National Coal Board (British Coal) of Great Britain commenced ergonomics in 1969, and Bureau of Mine of United States started human factor researches in same year. Japan has very short history

The science of human factors: separating fact from fiction.

Science.gov (United States)

Russ, Alissa L; Fairbanks, Rollin J; Karsh, Ben-Tzion; Militello, Laura G; Saleem, Jason J; Wears, Robert L

2013-10-01

Interest in human factors has increased across healthcare communities and institutions as the value of human centred design in healthcare becomes increasingly clear. However, as human factors is becoming more prominent, there is growing evidence of confusion about human factors science, both anecdotally and in scientific literature. Some of the misconceptions about human factors may inadvertently create missed opportunities for healthcare improvement. The objective of this article is to describe the scientific discipline of human factors and provide common ground for partnerships between healthcare and human factors communities. The primary goal of human factors science is to promote efficiency, safety and effectiveness by improving the design of technologies, processes and work systems. As described in this article, human factors also provides insight on when training is likely (or unlikely) to be effective for improving patient safety. Finally, we outline human factors specialty areas that may be particularly relevant for improving healthcare delivery and provide examples to demonstrate their value. The human factors concepts presented in this article may foster interdisciplinary collaborations to yield new, sustainable solutions for healthcare quality and patient safety.

Decolourization and degradation of azo Dye, Synozol Red HF6BN ...

African Journals Online (AJOL)

Decolourization and degradation of azo Dye, Synozol Red HF6BN, by Pleurotus ostreatus. Sidra Ilyas, Skinder Sultan Sultan, Abdul Rehman. Abstract. The present paper focuses on the use of fungus, Pleurotus ostreatus, to decolorize and degrade azo dye, Synazol Red HF6BN. Decolorization study showed that P.

Stellar Neutron Capture Cross Sections of the Lu and Hf Isotopes

International Nuclear Information System (INIS)

Wisshak, K.; Voss, F.; Kaeppeler, F.; Kazakov, L.; Krticka, M.

2005-01-01

The neutron capture cross sections of 175,176Lu and 176,177,178,179,180Hf have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator relative to the gold standard. Neutrons were produced by the 7Li(p,n)7Be reaction and capture events were detected by the Karlsruhe 4πBaF2 detector. The cross section ratios could be determined with uncertainties between 0.9 and 1.8% about a factor of five more accurate than previous data. A strong population of isomeric states was found in neutron capture of the Hf isotopes, which are only partially explained by CASINO/GEANT simulations based on the known level schemes.Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 keV and 100 keV. Severe differences up to40% were found to the data of a recent evaluation based on existing experimental results. The new data allow for a much more reliable analysis of the important branching in the s-process synthesis path at 176Lu which can be interpreted as an s-process thermometer

Very high latitude F-region irregularities observed by HF-radar backscatter

International Nuclear Information System (INIS)

Baker, K.B.; Greenwald, R.A.; Tsunoda, R.T.

1983-01-01

In February and March, 1982, a coherent scatter HF radar was operated from Cleary, Alaska to observe 7- to 15-m wavelength F-region plasma irregularities near the poleward edge of the auroral zone and in the polar cap. The radar operated for five days from February 25 to March 1 and produced approximately 700,000 Doppler spectra during that time. Of those nearly 700,000 spectra, approximately 10% showed backscattered power 3 dB or more above the noise level. A ray tracing technique using electron densities determined by the Chatanika incoherent scatter radar was used to predict locations where the HF waves were approximately normal to the magnetic field. If those locations were also to contain small scale electron density structure, then one would expect them to backscatter the HF waves. Several comparisons were made between predicted and observed locations of radiowave backscatter and excellent agreement was obtained. In addition, comparisons of the Doppler velocities observed by the coherent scatter HF radar and those observed by the Chatanika radar showed good agreement, suggesting that the plasma irregularities observed by the HF radar drift with the ambient plasma. In addition, average vector velocities calculated for the entire 5-day period show a flow pattern consistent with polar cap convection models. This again indicates that the irregularities drift with the plasma, as is predicted by a number of theories of F-region plasma irregularities. In the summer of 1983, the research program begun with those measurements will be continued with a steerable phased-array HF radar located at Goose Bay, Labrador, that will view the same ionospheric region as does the Sondre Stromfjord incoherent scatter radar

Human factors in atomic power plant

International Nuclear Information System (INIS)

Kawano, Ryutaro

1997-01-01

To ensure safety should have priority over all other things in atomic power plants. In Chernobyl accident, however, various human factors including the systems for bulb check after inspection and communication, troubles in the interface between hardwares such as warning speakers and instruments, and their operators, those in education and training for operators and those in the general management of the plant have been pointed out. Therefore, the principles and the practical measures from the aspect of human factors in atomic power plants were discussed here. The word, ''human factor'' was given a definition in terms of the direct cause and the intellectual system. An explanatory model for human factors, model SHEL constructed by The Tokyo Electric Power Co., Ltd., Inc. was presented; the four letter mean software(S), hardware(H), environment(E) and liveware(L). In the plants of the company, systemic measures for human error factors are taken now in all steps not only for design, operation and repairing but also the step for safety culture. Further, the level required for the safety against atomic power is higher in the company than those in other fields. Thus, the central principle in atomic power plants is changing from the previous views that technology is paid greater importance to a view regarding human as most importance. (M.N.)

Preparation, structure and properties of hafnium compounds in the system Hf-C-N-O

International Nuclear Information System (INIS)

Brundiers, G.D.

1975-08-01

Highly dense, homogenous and single phase hafnium carbonitride samples (with low oxygen content) were prepared in the whole concentration range of the ternary cubic carbonitrides. Stoichiometric hafnium oxicarbides were also prepared within the range of solubility. The procedure involved the hot pressing of powders of HfC, HfN, Hf, Hf-Oxide and carbon at temperatures of 3,000 0 C and pressures up to 550 kpf/cm 2 using a novel technique. Small single crystals of slightly substoichiometric HfN were also repared. The densification of the powders was studied as a function of the non-metal concentration. Carbonitrides with N/Hf ratio of 0.37 were prepared in a high temperature autoclave operating at medium pressures by the reaction of HfC with nitrogen. All the samples were characterized by density measurements, chemical, X-ray and metallographic analysis and in some cases with the aid of quantitative metallography and microprobe analysis. Typical properties investigated were lattice parameter, thermal expansion, microhardness and electrical resistivity as function of the non-metal content. For specific concentrations extreme values in the properties are attained. With the aid of the valence electron concentration (VEC) parameter, the properties can be correlated with the density of states of electrons at the Fermi level. (orig./HK) [de

Human factors issues for interstellar spacecraft

Science.gov (United States)

Cohen, Marc M.; Brody, Adam R.

1991-01-01

Developments in research on space human factors are reviewed in the context of a self-sustaining interstellar spacecraft based on the notion of traveling space settlements. Assumptions about interstellar travel are set forth addressing costs, mission durations, and the need for multigenerational space colonies. The model of human motivation by Maslow (1970) is examined and directly related to the design of space habitat architecture. Human-factors technology issues encompass the human-machine interface, crew selection and training, and the development of spaceship infrastructure during transtellar flight. A scenario for feasible instellar travel is based on a speed of 0.5c, a timeframe of about 100 yr, and an expandable multigenerational crew of about 100 members. Crew training is identified as a critical human-factors issue requiring the development of perceptual and cognitive aids such as expert systems and virtual reality.

Human Factors in Accidents Involving Remotely Piloted Aircraft

Science.gov (United States)

Merlin, Peter William

2013-01-01

This presentation examines human factors that contribute to RPA mishaps and provides analysis of lessons learned. RPA accident data from U.S. military and government agencies were reviewed and analyzed to identify human factors issues. Common contributors to RPA mishaps fell into several major categories: cognitive factors (pilot workload), physiological factors (fatigue and stress), environmental factors (situational awareness), staffing factors (training and crew coordination), and design factors (human machine interface).

Charge storage characteristics and tunneling mechanism of amorphous Ge-doped HfO{sub x} films

Energy Technology Data Exchange (ETDEWEB)

Qiu, X.Y.; Zhang, S.Y.; Zhang, T.; Wang, R.X.; Li, L.T.; Zhang, Y. [Southwest University, School of Physical Science and Technology, Chongqing (China); Dai, J.Y. [The Hong Kong Polytechnic University, Department of Applied Physics, Hong Kong (China)

2016-09-15

Amorphous Ge-doped HfO{sub x} films have been deposited on p-Si(100) substrates by means of RF magnetron sputtering. Microstructural investigations reveal the partial oxidation of doped Ge atoms in the amorphous HfO{sub x} matrix and the existence of HfSiO{sub x} interfacial layer. Capacitance-voltage hysteresis of the Ag-/Ge-doped HfO{sub x}/Si/Ag memory capacitor exhibits a memory window of 3.15 V which can maintain for >5 x 10{sup 4} cycles. Current-voltage characteristics reveal that Poole-Frenkel tunneling is responsible for electron transport in the Ge-doped HfO{sub x} film. (orig.)

The effects of sacubitril/valsartan on coronary outcomes in PARADIGM-HF

DEFF Research Database (Denmark)

Mogensen, Ulrik M.; Køber, Lars; Kristensen, Søren L.

2017-01-01

Background Angiotensin converting enzyme inhibitors (ACE-I), are beneficial both in heart failure with reduced ejection fraction (HF-REF) and after myocardial infarction (MI). We examined the effects of the angiotensin-receptor neprilysin inhibitor sacubitril/valsartan, compared with the ACE......-I enalapril, on coronary outcomes in PARADIGM-HF. Methods and results We examined the effect of sacubitril/valsartan compared with enalapril on the following outcomes: i) the primary composite endpoint of cardiovascular (CV) death or HF hospitalization, ii) a pre-defined broader composite including...... patients, compared with enalapril, sacubitril/valsartan reduced the risk of the primary outcome (HR 0.80 [0.73–0.87], P 

Assembly of the CMS HF (hadron forward) calorimeter, April 2003 to June 2005

CERN Multimedia

Tejinder S. Virdee, CERN

2005-01-01

The forward calorimeters (HF) of the CMS hadron calorimeter system are located 11.2 m from the interaction point. Each HF module is composed by 18 wedges, made of steel absorbers and radiation-hard quartz fibers. The photogallery shows the wedges (Figs. 1-3, April 2003), the assembly of one HF module (Figs. 4-9, May and June 2004) and the assembly of the other (Figs. 10-11, June 2005)

Human and Organizational Factors

International Nuclear Information System (INIS)

Eshiett, P.B.S.

2016-01-01

The Human and Organizational Factors Approach to Industrial Safety (HOFS) consists of identifying and putting in place conditions which encourage a positive contribution from operators (individually and in a team) with regards to industrial safety. The knowledge offered by the HOFS approach makes it possible better to understand what conditions human activity and to act on the design of occupational situations and the organization, in the aim of creating the conditions for safe work. Efforts made in this area can also lead to an improvement in results in terms of the quality of production or occupational safety (incidence and seriousness rates) (Daniellou, F., et al., 2011). Research on industrial accidents shows that they rarely happen as a result of a single event, but rather emerge from the accumulation of several, often seemingly trivial, malfunctions, misunderstandings, incorrect assumptions and other issues. The nuclear community has established rigorous international safety standards and concepts to ensure the protection of people and the environment from harmful effects of ionizing radiation (IAEA, 2014). A review of major human induced disasters in a number of countries and in different industries yields insights into several of the human and organizational factors involved in their occurrence. Some of these factors relate to failures in: • Design or technology; • Training; • Decision making; • Communication; • Preparation for the unexpected; • Understanding of organizational interdependencies

Toxicity levels to humans during acute exposure to hydrogen fluoride

International Nuclear Information System (INIS)

Halton, D.M.; Dranitsaris, P.; Baynes, C.J.

1984-11-01

A literature review was conducted of the acute toxicity of hydrogen fluoride (HF) with emphasis on the effects of inhalation of gaseous HF. The data and findings of the relevant references were summarized under four categories: animal studies, controlled human studies, community exposure and industrial exposure. These were critically reviewed and then lethal concentration-time relationships were developed for humans, corresponding to LCsub(LO), LCsub(10) and LCsub(50) levels. The effects of age, health and other physiological variables on the sensitivity to HF were discussed, as well as antagonistic and synergistic effects with other substances

Human Factors Throughout the Life Cycle: Lessons Learned from the Shuttle Program. [Human Factors in Ground Processing

Science.gov (United States)

Kanki, Barbara G.

2011-01-01

With the ending of the Space Shuttle Program, it is critical that we not forget the Human Factors lessons we have learned over the years. At every phase of the life cycle, from manufacturing, processing and integrating vehicle and payload, to launch, flight operations, mission control and landing, hundreds of teams have worked together to achieve mission success in one of the most complex, high-risk socio-technical enterprises ever designed. Just as there was great diversity in the types of operations performed at every stage, there was a myriad of human factors that could further complicate these human systems. A single mishap or close call could point to issues at the individual level (perceptual or workload limitations, training, fatigue, human error susceptibilities), the task level (design of tools, procedures and aspects of the workplace), as well as the organizational level (appropriate resources, safety policies, information access and communication channels). While we have often had to learn through human mistakes and technological failures, we have also begun to understand how to design human systems in which individuals can excel, where tasks and procedures are not only safe but efficient, and how organizations can foster a proactive approach to managing risk and supporting human enterprises. Panelists will talk about their experiences as they relate human factors to a particular phase of the shuttle life cycle. They will conclude with a framework for tying together human factors lessons-learned into system-level risk management strategies.

Structural, morphological, optical and photoluminescence properties of HfO2 thin films

International Nuclear Information System (INIS)

Ma, C.Y.; Wang, W.J.; Wang, J.; Miao, C.Y.; Li, S.L.; Zhang, Q.Y.

2013-01-01

Nanocrystalline monoclinic HfO 2 films with an average crystal size of 4.2–14.8 nm were sputter deposited under controlled temperatures and their structural characteristics and optical and photoluminescence properties have been evaluated. Structural investigations indicate that monoclinic HfO 2 films grown at higher temperatures above 400 °C are highly oriented along the (− 111) direction. The lattice expansion increases with diminishing HfO 2 crystalline size below 6.8 nm while maximum lattice expansion occurs with highly oriented monoclinic HfO 2 of crystalline size about 14.8 nm. The analysis of atomic force microscopy shows that the film growth at 600 °C can be attributed to the surface-diffusion-dominated growth. The intensity of the shoulderlike band that initiates at ∼ 5.7 eV and saturates at 5.94 eV shows continued increase with increasing crystalline size, which is intrinsic to nanocrystalline monoclinic HfO 2 films. Optical band gap varies in the range 5.40 ± 0.03–5.60 ± 0.03 eV and is slightly decreased with the increase in crystalline size. The luminescence band at 4.0 eV of HfO 2 films grown at room temperature can be ascribed to the vibronic transition of excited OH · radical while the emission at 3.2–3.3 eV for the films grown at all temperatures was attributed to the radiative recombination at impurity and/or defect centers. - Highlights: • Nanocrystalline monoclinic HfO 2 films were sputter deposited. • Structural, optical and photoluminescence properties were studied. • To analyze the scaling behavior using the power spectral density • Optical and photoluminescence properties strongly depend on film growth temperature

Temperature dependence of the resistivity and tunneling magnetoresistance of sputtered FeHf(Si)O cermet films

NARCIS (Netherlands)

Strijkers, G.J.; Swagten, H.J.M.; Rulkens, B.; Bitter, R.H.J.N.; Jonge, de W.J.M.; Bloemen, P.J.H.; Schep, K.M.

1998-01-01

We have studied the tunneling resistivity and magnetoresistance of reactive sputter deposited FeHfO and FeHfSiO thin granular films. Maximum magnetoresistance ratios at room temperature of 2% and 3.2% were observed for films with compositions of Fe47Hf10O43 and Fe40Hf6Si6O48, respectively. The

Efficacy of Sacubitril/Valsartan Relative to a Prior Decompensation: The PARADIGM-HF Trial.

Science.gov (United States)

Solomon, Scott D; Claggett, Brian; Packer, Milton; Desai, Akshay; Zile, Michael R; Swedberg, Karl; Rouleau, Jean; Shi, Victor; Lefkowitz, Martin; McMurray, John J V

2016-10-01

This study assessed whether the benefit of sacubtril/valsartan therapy varied with clinical stability. Despite the benefit of sacubitril/valsartan therapy shown in the PARADIGM-HF (Prospective Comparison of ARNI with ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) trial, it has been suggested that switching from an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker should be delayed until occurrence of clinical decompensation. Outcomes were compared among patients who had prior hospitalization within 3 months of screening (n = 1,611 [19%]), between 3 and 6 months (n = 1,009 [12%]), between 6 and 12 months (n = 886 [11%]), >12 months (n = 1,746 [21%]), or who had never been hospitalized (n = 3,125 [37%]). Twenty percent of patients without prior HF hospitalization experienced a primary endpoint of cardiovascular death or heart failure (HF) hospitalization during the course of the trial. Despite the increased risk associated with more recent hospitalization, the efficacy of sacubitril/valsartan therapy did not differ from that of enalapril according to the occurrence of or time from hospitalization for HF before screening, with respect to the primary endpoint or with respect to cardiovascular or all-cause mortality. Patients with recent HF decompensation requiring hospitalization were more likely to experience cardiovascular death or HF hospitalization than those who had never been hospitalized. Patients who were clinically stable, as shown by a remote HF hospitalization (>3 months prior to screening) or by lack of any prior HF hospitalization, were as likely to benefit from sacubitril/valsartan therapy as more recently hospitalized patients. (Prospective Comparison of ARNI with ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure [PARADIGM-HF]; NCT01035255). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

A Review of Various Performance Shaping Factors for Use in Advanced Control Rooms

International Nuclear Information System (INIS)

Lee, Seung Woo; Ha, Jun Su; Seong, Poong Hyun; Park, Jae Hyuk; Kim, Ja Kyung

2009-01-01

Human reliability analysis(HRA) has been performed as part of the probabilistic risk assessment to identify and quantify human actions and the associated impacts on structures, systems and components for a complex facility. Currently, representative HRA methods such as THERP, ASEP HRA and HCR are being used in Korea. In performing HRA, such conditions that influence human performances have been represented via several context factors. These context factors are referred to by different terms according to method: PSF(Performance Shaping Factors), PIF(Performance Influencing Factors), PAF(Performance Affecting Factors, EPC(Error Producing Conditions), CPC(Common Performance Conditions), and so on. These context factors which will be called PSFs in this study are used in adjusting the basic human error probability(BHEP). However, these PSFs need to be re-assessed since the context is expected to change due to the implementation of computer technologies in NPP. In this study, various PSFs used in different HRA methods are reviewed and PSFs which are frequently mentioned as important factors are derived. Also, HF(Human Factor) issues with one of the design characteristics of advanced NPP are identified

Evolution of Zr/Hf/Zr trilayers during annealing studied by RBS

International Nuclear Information System (INIS)

Kling, A.; Soares, J.C.

2010-01-01

The Zr/Hf system is highly interesting due its various applications, e.g. formation of amorphous ternary alloys, superconductive properties and production of gate oxide layers with high dielectric coefficients by oxidation of Zr/Hf multilayers. In this work Zr/Hf/Zr trilayers with an individual layer thickness of approximately 50 nm were deposited by electron gun evaporation on a substrate consisting of silicon covered by a micrometer thick thermal oxide layer. Samples were subjected to annealing procedures at 500 and 1200 o C in flowing air atmosphere to promote oxidation and Zr/Hf interdiffusion effects. RBS studies of the as-deposited and annealed samples were performed at the van-de-Graaff accelerator of ITN using He + and H + beams with energies between 2.0 and 2.525 MeV in order to study compositional changes induced by the heat treatment. In the case of low-temperature annealing the layer system appears, besides the oxidation process starting from the surface, to be stable. On the other hand, high-temperature annealing leads to an asymmetric Hf-diffusion into the surface and interior Zr-layer provoked by anomalous diffusion due to a phase transition in Zr accompanied by an almost complete oxidation of the layer structure Oxygen and metal depth distributions obtained by RBS in the as-deposited and treated samples are provided.

Development of human factors design review guidelines

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung Woon; Oh, In Suk; Suh, Sang Moon; Lee, Hyun Chul [Korea Atomic Energy Research Institute, Taejon (Korea)

1997-10-01

The objective of this study is to develop human factors engineering program review guidelines and alarm system review guidelines in order to resolve the two major technical issues: 25. Human Factors Engineering Program Review Model and 26. Review Criteria for Human Factors Aspects of Advanced Controls and Instrumentation, which are related to the development of human factors safety regulation guides being performed by KINS. For the development of human factors program review guidelines, we made a Korean version of NUREG-0711 and added our comments by considering Korean regulatory situation and reviewing the reference documents of NUREG-0711. We also computerized the Korean version of NUREG-0711, additional comments, and selected portion of the reference documents for the developer of safety regulation guides in KINS to see the contents comparatively at a glance and use them easily. For the development of alarm system review guidelines, we made a Korean version of NUREG/CR-6105, which was published by NRC in 1994 as a guideline document for the human factors review of alarm systems. Then we will update the guidelines by reviewing the literature related to alarm design published after 1994. (author). 12 refs., 5 figs., 2 tabs.

Enhancement of organic light-emitting device performances with Hf-doped indium tin oxide anodes

International Nuclear Information System (INIS)

Chen, T.-H.; Liou, Y.; Wu, T.J.; Chen, J.Y.

2004-01-01

We have enhanced the luminance and the power efficiency of organic light-emitting devices with Hf-doped indium tin oxide (ITO) anodes instead of a CuPc layer. The Hf-doped ITO layer with a thickness of 15 nm was deposited on top of the ITO anode. Less than 10 mol. % of Hf was doped in ITO films by adjusting the sputtering rates of both sources. The highest work function of the Hf-doped ITO layers was 5.4 eV at the Hf concentrations about 10 mol. %. The driving voltages of the device have been reduced by 1 V. A luminance of 1000 cd/m 2 at 7 mA/cm 2 , a current efficiency of 14 cd/A, and a power efficiency of 6 lm/W at 6 mA/cm 2 have been achieved in the device with a 4 mol. % Hf-doped ITO layer (work function=5.2 eV). In general, the performance was about 50% better than the device with a CuPc buffer layer

Aetiology, timing and clinical predictors of early vs. late readmission following index hospitalization for acute heart failure: insights from ASCEND-HF.

Science.gov (United States)

Fudim, Marat; O'Connor, Christopher M; Dunning, Allison; Ambrosy, Andrew P; Armstrong, Paul W; Coles, Adrian; Ezekowitz, Justin A; Greene, Stephen J; Metra, Marco; Starling, Randall C; Voors, Adriaan A; Hernandez, Adrian F; Michael Felker, G; Mentz, Robert J

2018-02-01

Patients hospitalized for heart failure (HF) are at high risk for 30-day readmission. This study sought to examine the timings and causes of readmission within 30 days of an HF hospitalization. Timing and cause of readmission in the ASCEND-HF (Acute Study of Clinical Effectiveness of Nesiritide and Decompensated Heart Failure) trial were assessed. Early and late readmissions were defined as admissions occurring within 0-7 days and 8-30 days post-discharge, respectively. Patients who died in hospital or remained hospitalized at day 30 post-randomization were excluded. Patients were compared by timing and cause of readmission. Logistic and Cox proportional hazards regression analyses were used to identify independent risk factors for early vs. late readmission and associations with 180-day outcomes. Of the 6584 patients (92%) in the ASCEND-HF population included in this analysis, 751 patients (11%) were readmitted within 30 days for any cause. Overall, 54% of readmissions were for non-HF causes. The median time to rehospitalization was 11 days (interquartile range: 6-18 days) and 33% of rehospitalizations occurred by day 7. Rehospitalization within 30 days was independently associated with increased risk for 180-day all-cause death [hazard ratio (HR) 2.38, 95% confidence interval (CI) 1.93-2.94; P readmission (HR 0.99, 95% CI 0.67-1.45; P = 0.94). In this hospitalized HF trial population, a significant majority of 30-day readmissions were for non-HF causes and one-third of readmissions occurred in the first 7 days. Early and late readmissions within the 30-day timeframe were associated with similarly increased risk for death. Continued efforts to optimize multidisciplinary transitional care are warranted to improve rates of early readmission. © 2017 The Authors. European Journal of Heart Failure © 2017 European Society of Cardiology.

Determining characteristics of HF communications links using SuperDARN

Directory of Open Access Journals (Sweden)

J. M. Hughes

2002-07-01

Full Text Available Space weather effects can strongly influence high-frequency (HF communications by changing the ionospheric environment through which the radio waves propagate. Since many systems utilize HF communications, the ability to make real-time assessments of propagation conditions is an important part of space weather monitoring systems. In this paper, we present new techniques for measuring high-latitude HF communications link parameters using data from SuperDARN radars. These techniques use ground-scatter returns to define the variation in skip distance with frequency. From these data, the maximum usable frequency (MUF as a function of range is determined and ionospheric critical frequencies are estimated. These calculations are made in near-real-time and the results are made available on the World Wide Web. F-region critical frequencies calculated using this method show good agreement with ionosonde data.Key words. Ionosphere (active experiments; instruments and techniques – Radio science (ionospheric propagation

Determining characteristics of HF communications links using SuperDARN

Directory of Open Access Journals (Sweden)

J. M. Hughes

Full Text Available Space weather effects can strongly influence high-frequency (HF communications by changing the ionospheric environment through which the radio waves propagate. Since many systems utilize HF communications, the ability to make real-time assessments of propagation conditions is an important part of space weather monitoring systems. In this paper, we present new techniques for measuring high-latitude HF communications link parameters using data from SuperDARN radars. These techniques use ground-scatter returns to define the variation in skip distance with frequency. From these data, the maximum usable frequency (MUF as a function of range is determined and ionospheric critical frequencies are estimated. These calculations are made in near-real-time and the results are made available on the World Wide Web. F-region critical frequencies calculated using this method show good agreement with ionosonde data.

Key words. Ionosphere (active experiments; instruments and techniques – Radio science (ionospheric propagation

SIMS study of oxygen diffusion in monoclinic HfO2

Science.gov (United States)

Mueller, Michael P.; De Souza, Roger A.

2018-01-01

The diffusion of oxygen in dense ceramics of monoclinic HfO2 was studied by means of (18O/16O) isotope exchange annealing and subsequent determination of isotope depth profiles by Secondary Ion Mass Spectrometry. Anneals were performed in the temperature range of 573 ≤T /K ≤ 973 at an oxygen partial pressure of p O2=200 mbar . All measured isotope profiles exhibited two features: the first feature, closer to the surface, was attributed mainly to slow oxygen diffusion in an impurity silicate phase; the second feature, deeper in the sample, was attributed to oxygen diffusion in bulk monoclinic HfO2 . The activation enthalpy of oxygen tracer diffusion in bulk HfO2 was found to be ΔHD∗≈0.5 eV .

Photon strength function in the Hf-181 nucleus by method of two-step cascade

International Nuclear Information System (INIS)

Le Hong Khiem

2003-01-01

The applicability of sum-coincidence measurements of two-step cascade gamma ray spectra determining Photon Strength Function (PSF) of Hf-181 induced from Hf-180 (n,2γ) Hf-181 reaction is presented. Up to 80% intensity of the primary gamma ray transitions in a wide energy range have been deduced and compared to model calculation. (author)

Human Factors in Space Exploration

Science.gov (United States)

Jones, Patricia M.; Fiedler, Edna

2010-01-01

The exploration of space is one of the most fascinating domains to study from a human factors perspective. Like other complex work domains such as aviation (Pritchett and Kim, 2008), air traffic management (Durso and Manning, 2008), health care (Morrow, North, and Wickens, 2006), homeland security (Cooke and Winner, 2008), and vehicle control (Lee, 2006), space exploration is a large-scale sociotechnical work domain characterized by complexity, dynamism, uncertainty, and risk in real-time operational contexts (Perrow, 1999; Woods et ai, 1994). Nearly the entire gamut of human factors issues - for example, human-automation interaction (Sheridan and Parasuraman, 2006), telerobotics, display and control design (Smith, Bennett, and Stone, 2006), usability, anthropometry (Chaffin, 2008), biomechanics (Marras and Radwin, 2006), safety engineering, emergency operations, maintenance human factors, situation awareness (Tenney and Pew, 2006), crew resource management (Salas et aI., 2006), methods for cognitive work analysis (Bisantz and Roth, 2008) and the like -- are applicable to astronauts, mission control, operational medicine, Space Shuttle manufacturing and assembly operations, and space suit designers as they are in other work domains (e.g., Bloomberg, 2003; Bos et al, 2006; Brooks and Ince, 1992; Casler and Cook, 1999; Jones, 1994; McCurdy et ai, 2006; Neerincx et aI., 2006; Olofinboba and Dorneich, 2005; Patterson, Watts-Perotti and Woods, 1999; Patterson and Woods, 2001; Seagull et ai, 2007; Sierhuis, Clancey and Sims, 2002). The human exploration of space also has unique challenges of particular interest to human factors research and practice. This chapter provides an overview of those issues and reports on sorne of the latest research results as well as the latest challenges still facing the field.

Dosimetry of ultraviolet radiation with BaHfO{sub 3} powders; Dosimetria de radiacion ultravioleta con polvos de BaHfO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Barrera A, A. A.; Aguilar D, G. A.; Guzman M, J.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Ciudad de Mexico (Mexico); Ceron R, V., E-mail: abalba1@hotmail.com [Universidad de Guanajuato, 37670 Leon, Guanajuato (Mexico)

2016-10-15

Ceramic materials based on pure barium hafnate (BaHfO{sub 3}) have been obtained as a powder by the co-precipitation method. The powders obtained have a cubic structure that favors the thermoluminescent and optical properties, through which a better detection of the non-ionizing radiation is allowed. With these powders various tests were performed in the ultraviolet range at different exposure times. These thermoluminescent (Tl) studies were carried out using a Tl 3500 hand held reader which yielded a brightness curve that ranged from room temperature to the 350 degrees Celsius. This BaHfO{sub 3} response exhibits a broad brightness curve with a single peak centered around 225 degrees Celsius. Finally, is reported that there are materials of barium hafnate (BaHfO{sub 3}) doped with some rare earths (Eu, Tb) which, instead of improving the performance of the powders, decrease it, so that the use of intrinsic barium hafnate is the most appropriate. (Author)

Accidents and human factors

International Nuclear Information System (INIS)

Nishiwaki, Y.; Kawai, H.; Morishima, H.; Terano, T.; Sugeno, M.

1984-01-01

When the TMI accident occurred it was 4 a.m., an hour when the error potential of the operators would have been very high. The frequency of car and train accidents in Japan is also highest between 4 a.m. and 6 a.m. The error potential may be classified into five phases corresponding to the electroencephalogramic pattern (EEG). At phase 0, when the delta wave appears, a person is unconscious and in deep sleep; at phase I, when the theta wave appears, he is very tired, sleepy and subnormal; at phase II, when the alpha wave appears, he is normal, relaxed and passive; at phase III, when the beta wave appears, he is normal, clear-minded and active; at phase IV, when the strong beta or epileptic wave appears, he is hypernormal, excited and incapable of normal judgement. Should an accident occur at phase II, the brain condition may jump to phase IV. At this phase the error or accident potential is maximum. The response of the human brain to different types of noises and signals may vary somewhat for different individuals and for different groups of people. Therefore, the possibility that such differences in brain functions may influence the mental structure would be worthy of consideration in human factors and in the design of man-machine systems. Human reliability and performance would be affected by many factors: medical, physiological and psychological, etc. The uncertainty involved in human factors may not necessarily be probabilistic, but fuzzy. Therefore, it would be important to develop a theory by which both non-probabilistic uncertainties, or fuzziness, of human factors and the probabilistic properties of machines can be treated consistently. From the mathematical point of view, probabilistic measure is considered a special case of fuzzy measure. Therefore, fuzzy set theory seems to be an effective tool for analysing man-machine systems. To minimize human error and the possibility of accidents, new safety systems should not only back up man and make up for his

Human Modeling for Ground Processing Human Factors Engineering Analysis

Science.gov (United States)

Stambolian, Damon B.; Lawrence, Brad A.; Stelges, Katrine S.; Steady, Marie-Jeanne O.; Ridgwell, Lora C.; Mills, Robert E.; Henderson, Gena; Tran, Donald; Barth, Tim

2011-01-01

There have been many advancements and accomplishments over the last few years using human modeling for human factors engineering analysis for design of spacecraft. The key methods used for this are motion capture and computer generated human models. The focus of this paper is to explain the human modeling currently used at Kennedy Space Center (KSC), and to explain the future plans for human modeling for future spacecraft designs

Alloy 33: A new material for the handling of HNO3/HF media in reprocessing of nuclear fuel

International Nuclear Information System (INIS)

Koehler, M.; Heubner, U.; Eichenhofer, K.W.; Renner, M.

1997-01-01

Alloy 33, an austenitic 33Cr-32Fe-31Ni-1.6Mo-0.6Cu-0.4N material shows excellent resistance to corrosion when exposed to highly oxidizing media as e.g. HNO 3 and HNO 3 /HF mixtures which are encountered in reprocessing of nuclear fuel. According to the test results available so far, resistance to corrosion in boiling azeotropic (67%) HNO 3 is about 6 and 2 times superior to AISI 304 L and 310 L. In higher concentrated nitric acid it can be considered corrosion resistant up to 95% HNO 3 at 25 C, up to 90% HNO 3 at 50 C and up to somewhat less than 85% HNO 3 at 75 C. In 20% HNO 3 /7% HF at 50 C its resistance to corrosion is superior to AISI 316 Ti and Alloy 28 by factors of about 200 and 2.4. Other media tested with different results include 12% HNO 3 with up to 3.5% HF and 0.4% HF with 32 to 67.5% HNO 3 at 90 C. Alloy 33 is easily fabricated into all product forms required for chemical plants (e.g. plate, sheet, strip, wire, tube and flanges). Components such as dished ends and tube to tube sheet weldments have been successfully fabricated facilitating the use of Alloy 33 for reprocessing of nuclear fuel

Mid-Latitude Mobile Wideband HF- NVIS Channel Analysis: Part 1

Science.gov (United States)

2017-09-14

commercial satellite communications (SATCOM) for beyond line-of-sight (LOS) links. However, standard HF systems operating over a 3-kHz bandwidth do not...citation of trade names and names of names of manufacturers is not to be construed as official government endorsement or approval of commercial ...Division EXECUTIVE SUMMARY High frequency (HF) links (2 to 30 MHz) are an alternative to the cost and tactical fragility of commercial satellite

Mechanical properties of ultra-thin HfO{sub 2} films studied by nano scratches tests

Energy Technology Data Exchange (ETDEWEB)

Fu, Wei-En; Chang, Yong-Qing [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321, Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Chang, Chia-Wei; Yao, Chih-Kai [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Jiunn-Der, E-mail: jdliao@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

2013-02-01

10-nm-thick atomic layer deposited HfO{sub 2} films were characterized in terms of wear resistance and indentation hardness to investigate the thermal annealing induced impacts on mechanical properties. The wear resistance of ultra-thin films at low loads was characterized using nano-scratch tests with an atomic force microscope. The depth of the nano-scratches decreases with increasing annealing temperature, indicating that the hardness of the annealed films increases with the annealing temperatures. Surface nanoindentation was also performed to confirm the nanoscratch test results. The hardness variation of the annealed films is due to the generation of HfSi{sub x}O{sub y} induced by the thermal annealing. X-ray photoelectron spectroscopy measurements proved that the hardness of formed HfSi{sub x}O{sub y} with increasing annealing temperatures. The existence of HfSi{sub x}O{sub y} broadens the interface, and causes the increase of the interfacial layer thickness. As a result, the surface hardness increases with the increasing HfSi{sub x}O{sub y} induced by the thermal annealing. - Highlights: ► Mechanical properties of HfO{sub 2} films were assessed by nano-scratch and indentation. ► Scratch depth of HfO{sub 2} films decreased with the increase of annealing temperatures. ► Nano-hardness of HfO{sub 2} films increased with the increase of annealing temperatures.

Human Leptospirosis and risk factors.

Directory of Open Access Journals (Sweden)

Yanelis Emilia Tabío Henry

2010-09-01

Full Text Available The human leptospirosis is a zoonosis of world distribution, were risk factors exist that have favored the wild and domestic animal propagation and so man. A descpitive investigation was made with the objective of determining the behavior of risk factors in outpatients by human leptospirosis in “Camilo Cienfuegos“ University General Hospital from Sncti Spíritus In the comprised time period betwen december 1 st and 3 st , 2008.The sample of this study was conformed by 54 risk persons that keep inclusion criteria. Some variables were used:age, sex, risk factors and number of ill persons, according to the month. Some patients of masculine sex prevailed (61,9%, group of ages between 15-29 and 45-59 years (27,7%, patients treated since october to december (53,7%, the direct and indirect contact with animals (46,2 %. The risk factors cassually associated to human leptospirosis turned to be: the masculine sex, the contac with animals, the occupational exposition and the inmersion on sources of sweet water.

Human factors of safety: a few landmarks

International Nuclear Information System (INIS)

Mosneron Dupin, F.

1992-06-01

This paper discusses factors to be taken into account, and methods to be used. It concludes that more realistic and positive conceptions of Human Factors should be developed, and that Human Factors should be addressed at the very beginning of any technical project

Beta decomposition of (Hf/sub x/Zr/sub 1-x/)80Nb20 ternary alloys

International Nuclear Information System (INIS)

Jones, W.B.; Taggart, R.; Polonis, D.H.

1978-01-01

The processes of beta decomposition have been examined in ternary alloys of the form (Hf/sub x/Zr/sub 1-x/) 80 Nb 20 to determine the influence of Hf additions to a basic Zr 80 Nb 20 composition. In the chill cast condition, Hf additions have been found to decrease the temperature coefficient of electrical resistivity from a value of -0.0015%/K for the binary Zr 80 Nb 20 alloy to a value of -0.011%/K for a (Hf 50 Zr 50 ) 80 Nb 20 ternary alloy. This change is explained in terms of the bcc lattice instability typical of Ti, Zr, and Hf alloys. The Hf additions enhance the kinetics of omega-phase precipitation during aging at 648 K. The aging of a (Hf 05 Zr 95 ) 80 Nb 20 alloy for 12 h results in the precipitation of a high volume fraction of cuboidal shaped omega-phase particles. A phase separation which results in the formation of solute lean discs (β/sub l/) occurs together with the precipitation of the omega-phase. These discs formed both randomly within the matrix and heterogeneously along dislocations and at grain boundaries

Systems Tl2MoO4-E(MoO4)2, where E=Zr or Hf, and the crystal structure of Tl8Hf(MoO4)6

International Nuclear Information System (INIS)

Bazarov, B.G.; Bazarova, Ts.T.; Fedorov, K.N.; Bazarova, Zh.G.; Chimitova, O.D.; Klevtsova, R.F.; Glinskaya, L.A.

2006-01-01

Systems Tl 2 MoO 4 -E(MoO 4 ) 2 (E=Zr, Hf) were studied by X-ray diffraction, differential thermal analysis and IR spectroscopy. Formation of Tl 8 E(MoO 4 ) 6 and Tl 2 E(MoO 4 ) 2 compounds was established. Phase T-x diagrams of the Tl 2 MoO 4 -Zr(MoO 4 ) 2 system were constructed. Monocrystals were grown, and structure of Tl 8 Hf(MoO 4 ) 6 was studied. The compound is crystallized in monoclinic syngony with elementary cell parameters a=9.9688(6), b=18.830(1), c=7.8488(5) A, β=108.538(1) Deg, Z=2, sp. gr. C2/m. The isolated group [HfMo 6 O 24 ] 8- is responsible for fundamental fragment of the structure. Three varieties of crystallographically independent Tl-polyhedra fill space evenly between fragments [HfMo 6 O 24 ] 8- forming three-dimensional form [ru

Tunneling current in HfO2 and Hf0.5Zr0.5O2-based ferroelectric tunnel junction

Science.gov (United States)

Dong, Zhipeng; Cao, Xi; Wu, Tong; Guo, Jing

2018-03-01

Ferroelectric tunnel junctions (FTJs) have been intensively explored for future low power data storage and information processing applications. Among various ferroelectric (FE) materials studied, HfO2 and H0.5Zr0.5O2 (HZO) have the advantage of CMOS process compatibility. The validity of the simple effective mass approximation, for describing the tunneling process in these materials, is examined by computing the complex band structure from ab initio simulations. The results show that the simple effective mass approximation is insufficient to describe the tunneling current in HfO2 and HZO materials, and quantitative accurate descriptions of the complex band structures are indispensable for calculation of the tunneling current. A compact k . p Hamiltonian is parameterized to and validated by ab initio complex band structures, which provides a method for efficiently and accurately computing the tunneling current in HfO2 and HZO. The device characteristics of a metal/FE/metal structure and a metal/FE/semiconductor (M-F-S) structure are investigated by using the non-equilibrium Green's function formalism with the parameterized effective Hamiltonian. The result shows that the M-F-S structure offers a larger resistance window due to an extra barrier in the semiconductor region at off-state. A FTJ utilizing M-F-S structure is beneficial for memory design.

Preparation and characterization of Ce-doped HfO2 nanoparticles

International Nuclear Information System (INIS)

Gálvez-Barboza, S.; González, L.A.; Puente-Urbina, B.A.; Saucedo-Salazar, E.M.; García-Cerda, L.A.

2015-01-01

Highlights: • Ce-doped HfO 2 nanoparticles were prepared by a modified solgel method. • Ce-doped HfO 2 nanoparticles have a semispherical shape with sizes between 6 and 11.5 nm. • The samples doped with 10% in weight of Ce directly crystallized in a cubic structure. • A quick, straightforward and effective route for the preparation of Ce-doped nanoparticles. - Abstract: A modified solgel method to synthesize Ce-doped HfO 2 nanoparticles was carried out using a precursor material prepared with cerium nitrate, hafnium chloride, citric acid and ethylene glycol. The obtained precursor material was calcined at 500 and 700 °C for 2 h in air. The influence of the concentration of Ce and the calcination temperature was studied to observe the structural and morphological changes of the obtained materials. For the characterization, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman scattering (RS) were employed. The XRD patterns shown that the Ce-doped HfO 2 undergoes a structural transformation from monoclinic to cubic phase, which is significantly dependent on the Ce content and calcination temperature. TEM images have also confirmed the existence of semispherical nanoparticles with sizes between 6 and 11.5 nm

ACSNI study group on human factors

International Nuclear Information System (INIS)

1993-01-01

Organisational failures are now recognised as being as important as mechanical failures or individual human errors in causing major accidents such as the capsize of the Herald of Free Enterprise or the Pipa Alpha disaster. The Human Factors Study Group of the Advisory Committee on the Safety of Nuclear Installations was set up to look at the part played by human factors in nuclear risk and its reduction. The third report of the Study Group considers the role played by organisational factors and management in promoting nuclear safety. Actions to review and promote a safety culture are suggested. Three main conclusions are drawn and several recommendations made. (UK)

Determining the Sensitivity of the Hf-Nd Proxy to Glacial Weathering

Science.gov (United States)

Namsinh, A.; Scher, H.; Piotrowski, A. M.

2017-12-01

The history of polar ice sheets through the Cenozoic is incompletely known. Estimates of the onset of northern hemisphere glaciation range from the Pliocene to mid-Eocene and precursor Antarctic glaciations are believed to have commenced in the middle Eocene. Uncertainty surrounding the history of ice sheets has resulted in debates about the sensitivity of ice sheets to changes in atmospheric CO2 through the Cenozoic. Geochemical proxies for continental weathering — particularly those that are sensitive to mechanical breakdown of the upper continental crust by ice sheets — could improve the fidelity of paleoclimate reconstructions of ice sheet history. Coupled hafnium (Hf) and neodymium (Nd) isotopes in seawater and authigenic sediment phases show a strong correlation with mechanical weathering rates, however the proxy has not been systematically tested on Pleistocene time scales. We measured the Hf and Nd isotope ratios of authigenic and detrital phases of sediment cores from 1150 m to 4045 m depth on the Rockall Plateau in the NE Atlantic Ocean. Our study is limited to the LGM, deglaciation and Holocene intervals. The authigenic fraction was extracted from bulk sediments by leaching with dilute hydroxylamine hydrochloride and EDTA to prevent readsorption of Hf. A stronger leach solution was then used to isolate the terrigenous detrital fraction. The fidelity of the seawater signal obtained by leaching is assessed by comparison of leachate eNd values to previously published eNd values from uncleaned forams from the same depth intervals. Initial tests with Holocene and deglacial samples verify that leachate eNd values are statistically indistinguishable from uncleaned forams. Shale-normalized REE patterns for leachates reveal negative Ce anomalies and a MREE enrichment typical of Fe-Mn oxydydroxide phases. Coupled Hf-Nd isotopes from authigenic leachates from our initial tests fall along the Seawater Array when plotted on a Hf-Nd isotope diagram, confirming

Optical properties of a HfO2/Si stack with a trace amount of nitrogen incorporation

Science.gov (United States)

Ye, Li; Tingting, Jiang; Qingqing, Sun; Pengfei, Wang; Shijin, Ding; Wei, Zhang

2012-03-01

HfO2 films were deposited by atomic layer deposition through alternating pulsing of Hf[N(C2H5)(CH3)]4 and H2O2. A trace amount of nitrogen was incorporated into the HfO2 through ammonia annealing. The composition, the interface stability of the HfO2/Si stack and the optical properties of the annealed films were analyzed to investigate the property evolution of HfO2 during thermal treatment. With a nitrogen concentration increase from 1.41 to 7.45%, the bandgap of the films decreased from 5.82 to 4.94 eV.

Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

International Nuclear Information System (INIS)

Zhang, H.Y.; He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C.; Zhuge, L.J.; Wu, X.M.

2015-01-01

HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO x are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf 2+ and Hf 4+ . The HfErO films are composed with the structures of HfO 2 , HfO and ErO x , which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO 2 in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO 2 are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

Searching triaxial superdeformation in 175Hf

International Nuclear Information System (INIS)

Li Xiaowei; Zhejiang Normal Univ., Jinhua; Yu Shaoying; Zhejiang Normal Univ., Jinhua; Chinese Academy of Sciences, Beijing; Shen Caiwan; National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou; Chen Yongshou; Chinese Academy of Sciences, Beijing; National Laboratory of Heavy Ion Accelerator of Lanzhou

2006-01-01

A two-dimensional Total Routhian Surface (TRS) calculation is carried out in order to ascertain if there is triaxial superdeformation in 175 Hf. A five quasi-particle configuration is chosen in the calculation. Unfortunately, the TRS minimum does not show up in the total potential energy surface. (authors)

Human Factor in Therapeutic Relationship

Directory of Open Access Journals (Sweden)

Ramazan Akdogan

2011-03-01

Full Text Available herapeutic relationship is a professional relationship that has been structured based on theoretical props. This relationship is a complicated, wide and unique relationship which develops between two people, where both sides' personality and attitudes inevitably interfere. Therapist-client relationship experienced through transference and counter transference, especially in psychodynamic approaches, is accepted as the main aspect of therapeutic process. However, the approaches without dynamic/deterministic tendency also take therapist-client relationship into account seriously and stress uniqueness of interaction between two people. Being a person and a human naturally sometimes may negatively influence the relationship between the therapist and client and result in a relationship going out of the theoretical frame at times. As effective components of a therapeutic process, the factors that stem from being human include the unique personalities of the therapist and the client, their values and their attitude either made consciously or subconsciously. Literature has shown that the human-related factors are too effective to be denied in therapeutic relationship process. Ethical and theoretical knowledge can be inefficient to prevent the negative effects of these factors in therapeutic process at which point a deep insight and supervision would have a critical role in continuing an acceptable therapeutic relationship. This review is focused on the reflection of some therapeutic factors resulting from being human and development of counter transference onto the therapeutic process.

Development of human factors design review guidelines

International Nuclear Information System (INIS)

Lee, Jung Woon; Oh, In Suk; Suh, Sang Moon; Lee, Hyun Chul

1997-10-01

The Objective of this study is to develop human factors engineering program review guidelines and alarm system review guidelines in order to resolve the two major technical issues: '25, Human factors engineering program review model' and '26, Review criteria for human actors aspects of advanced controls and instrumentation', which are related to the development of human factors safety regulation guides be ing performed by KINS. For the development of human factors program review guidelines, we made a Korean version of NUREG-0711 and added our comments by considering Korean regulatory situation and reviewing the reference documents of NUREG-0711. We also computerized the Korean version of NUREG-0711, additional comments, and selected portion of the reference documents for the developer of safety regulation guides in KINS to see the contents comparatively at a glance and use them easily. For the development of alarm system review guidelines, we made a Korean version of NUREG/CR-6105, which was published by NRC in 1994 as a guideline document for the human factors review of alarm systems. Then we well update the guidelines by reviewing the literature related to alarm design published after 1994

Human Research Program: Space Human Factors and Habitability Element

Science.gov (United States)

Russo, Dane M.

2007-01-01

The three project areas of the Space Human Factors and Habitability Element work together to achieve a working and living environment that will keep crews healthy, safe, and productive throughout all missions -- from Earth orbit to Mars expeditions. The Advanced Environmental Health (AEH) Project develops and evaluates advanced habitability systems and establishes requirements and health standards for exploration missions. The Space Human Factors Engineering (SHFE) Project s goal is to ensure a safe and productive environment for humans in space. With missions using new technologies at an ever-increasing rate, it is imperative that these advances enhance crew performance without increasing stress or risk. The ultimate goal of Advanced Food Technology (AFT) Project is to develop and deliver technologies for human centered spacecraft that will support crews on missions to the moon, Mars, and beyond.

Human hair follicle organ culture: theory, application and perspectives.

Science.gov (United States)

Langan, Ewan A; Philpott, Michael P; Kloepper, Jennifer E; Paus, Ralf

2015-12-01

For almost a quarter of a century, ex vivo studies of human scalp hair follicles (HFs) have permitted major advances in hair research, spanning diverse fields such as chronobiology, endocrinology, immunology, metabolism, mitochondrial biology, neurobiology, pharmacology, pigmentation and stem cell biology. Despite this, a comprehensive methodological guide to serum-free human HF organ culture (HFOC) that facilitates the selection and analysis of standard HF biological parameters and points out both research opportunities and pitfalls to newcomers to the field is still lacking. The current methods review aims to close an important gap in the literature and attempts to promote standardisation of human HFOC. We provide basic information outlining the establishment of HFOC through to detailed descriptions of the analysis of standard read-out parameters alongside practical examples. The guide closes by pointing out how serum-free HFOC can be utilised optimally to obtain previously inaccessible insights into human HF biology and pathology that are of interest to experimental dermatologists, geneticists, developmental biologists and (neuro-) endocrinologists alike and by highlighting novel applications of the model, including gene silencing and gene expression profiling of defined, laser capture-microdissected HF compartments. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Feasibility study of data transmission via HF link from a small UAV platform

OpenAIRE

Enander, Filip

2017-01-01

The High Frequency (HF) band, 3-30 MHz, is used when no infrastructure for long-range communications is available. New technology, such as digital signal processing enables higher data rate in the HF band, which in 2000s has resulted in increased commercial use. Reflection of radio waves in the ionosphere allows for beyond horizon communication, and are a unique property of the HF band. However, properties of the ionosphere are highly dependent of radiation from the sun, which varies with geo...

Human Factors in Nuclear Reactor Accidents

International Nuclear Information System (INIS)

Mustafa, M.E.

2016-01-01

While many people would blame nature for the disaster of the “Fukushima Daiichi” accident, experts considered this accident to be also a human-induced disaster. This confirmed the importance of human errors which have been getting a growing interest in the nuclear field after the Three Mile Island accident. Personnel play an important role in design, operation, maintenance, planning, and management. The interface between machine and man is known as a human factor. In the present work, the human factors that have to be considered were discussed. The effect of the control room configuration and equipment design effect on the human behavior was also discussed. Precise reviewing of person’s qualifications and experience was focused. Insufficient training has been a major cause of human error in the nuclear field. The effective training issues were introduced. Avoiding complicated operational processes and non responsive management systems was stressed. Distinguishing between the procedures for normal and emergency operations was emphasised. It was stated that human error during maintenance and testing activities could cause a serious accident. This is because safety systems do not cover much more risk probabilities in the maintenance and testing activities like they do in the normal operation. In nuclear industry, the need for a classification and identification of human errors has been well recognised. As a result of this, human reliability must be assessed. These errors are analyzed by a probabilistic safety assessment which deals with errors in reading, listening and implementing procedures but not with cognitive errors. Much efforts must be accomplished to consider cognitive errors in the probabilistic safety assessment. The ways of collecting human factor data were surveyed. The methods for identifying safe designs, helping decision makers to predict how proposed or current policies will affect safety, and comprehensive understanding of the relationship

Young Human Cholinergic Neurons Respond to Physiological Regulators and Improve Cognitive Symptoms in an Animal Model of Alzheimer’s Disease

Directory of Open Access Journals (Sweden)

Annamaria Morelli

2017-10-01

Full Text Available The degeneration of cholinergic neurons of the nucleus basalis of Meynert (NBM in the basal forebrain (BF is associated to the cognitive decline of Alzheimer’s disease (AD patients. To date no resolutive therapies exist. Cell-based replacement therapy is a strategy currently under consideration, although the mechanisms underlying the generation of stem cell-derived NBM cholinergic neurons able of functional integration remain to be clarified. Since fetal brain is an optimal source of neuronal cells committed towards a specific phenotype, this study is aimed at isolating cholinergic neurons from the human fetal NBM (hfNBMs in order to study their phenotypic, maturational and functional properties. Extensive characterization confirmed the cholinergic identity of hfNBMs, including positivity for specific markers (such as choline acetyltransferase and acetylcholine (Ach release. Electrophysiological measurements provided the functional validation of hfNBM cells, which exhibited the activation of peculiar sodium (INa and potassium (IK currents, as well as the presence of functional cholinergic receptors. Accordingly, hfNBMs express both nicotinic and muscarinic receptors, which were activated by Ach. The hfNBMs cholinergic phenotype was regulated by the nerve growth factor (NGF, through the activation of the high-affinity NGF receptor TrkA, as well as by 17-β-estradiol through a peculiar recruitment of its own receptors. When intravenously administered in NBM-lesioned rats, hfNBMs determined a significant improvement in memory functions. Histological examination of brain sections showed that hfNBMs (labeled with PKH26 fluorescent dye prior to administration reached the damaged brain areas. The study provides a useful model to study the ontogenetic mechanisms regulating the development and maintenance of the human brain cholinergic system and to assess new lines of research, including disease modeling, drug discovery and cell-based therapy for AD.

Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Zhang, H.Y. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Nanjing University of Posts and Telecommunications, School of Tongda, Nanjing (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Zhuge, L.J. [Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Soochow University, Analysis and Testing Center, Suzhou (China); Wu, X.M. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai (China)

2015-01-23

HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO{sub x} are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf{sup 2+} and Hf{sup 4+}. The HfErO films are composed with the structures of HfO{sub 2}, HfO and ErO{sub x}, which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO{sub 2} in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO{sub 2} are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

Development of a Field Management Standard for Improving Human Factors

International Nuclear Information System (INIS)

Yun, Young Su; Son, Il Moon; Son, Byung Chang; Kwak, Hyo Yean

2009-07-01

This project is to develop a management guideline for improving human performances as a part of the Human Factors Management System of Kori unit 1 which is managing all of human factors items such as man-machine system interfaces, work procedures, work environments, and human reliabilities in nuclear power plants. Human factors engineering includes an human factors suitability analysis and improvement of human works, an analysis of accidents by human error, an improvement of work environment, an establishment of human factors management rules and a development of human resources to manage and perform those things consistently. For assisting these human factors engineering tasks, we developed human factors management guidelines, checklists and work procedures to be used in staffing, qualification, training, and human information requirements and workload. We also provided a software tool for managing the above items. Additionally, contents and an item pool for a human factors qualifying examination and training programs were developed. A procedures improvement and a human factors V and V on the Kori unit 1 have been completed as a part of this project, too

ATMEA1 Nuclear Power Plant. Overview of the HF engineering program

International Nuclear Information System (INIS)

Rivere, Cyril; Mashio, Kenji; Martinez-Pellegrini, Diego

2015-01-01

ATMEA, a joint-venture between AREVA and Mitsubishi Heavy Industries has developed the ATMEA1 Pressurized Water Reactor (PWR) Nuclear Island (NI), leveraging both of its shareholders’ proficient technologies, innovations and experiences. The scope of the ATMEA1 PWR development covers the complete scope of engineering works necessary to develop a standard product. As a recently emergent discipline in the field of nuclear plant engineering, Human Factor Engineering (HFE) is one of the challenges which has to be integrated within new plant development process. At early design stages of ATMEA1 development, ATMEA has defined and implemented an extensive NUREG-based HFE program, encompassing HFE Preliminary Analyses, Human-Systems Interfaces (HSI) Design and Verification and Validation (V and V) activities. The HFE Preliminary Analyses are defined through Operating Experience Review (OER), Functional Requirement Analysis and Function Allocation (FRA/FA) and Task Analysis (TA). Human-System Interface (HSI) Design and related V and V activities are based on Control Center, Control Rooms and Human-Machine Interfaces (HMIs). All these steps are implemented within the ATMEA Project through a structured generic documentation basis by a HFE team composed of HF specialists from both AREVA and MHI and managed by ATMEA. ATMEA1 development project aims to develop flexible and robust design and process which can be easily adapted to be compliant to any regulations over the world. U.S. regulatory guidelines related to HFE (e.g. ref. [1] and ref. [2]) were applied as a basis for this project. This paper presents the overall ATMEA1 HFE program content and the related process used to favor its implementation within the Project; through the collaboration between MHI and AREVA under ATMEA lead. A special focus is made on the HFE team composition, roles and responsibilities, the management of interfaces with the relevant engineering disciplines and the tools used to support the HFE

MoS{sub 2} on an amorphous HfO{sub 2} surface: An ab initio investigation

Energy Technology Data Exchange (ETDEWEB)

Scopel, W. L., E-mail: wlscopel@if.uff.br [Departamento de Física, Universidade Federal do Espírito Santo, Vitória, Brazil and Departamento de Ciências Exatas, Universidade Federal Fluminense, Volta Redonda, Rio de Janerio (Brazil); Miwa, R. H., E-mail: hiroki@infis.ufu.br; Schmidt, T. M., E-mail: tome@infis.ufu.br [Instituto de Física, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais (Brazil); Venezuela, P., E-mail: vene@if.uff.br [Instituto de Física, Universidade Federal Fluminense, Niterói, Rio de Janerio (Brazil)

2015-05-21

The energetic stability, electronic and structural properties of MoS{sub 2} adsorbed on an amorphous a-HfO{sub 2} surface (MoS{sub 2}/HfO{sub 2}) are examined through ab initio theoretical investigations. Our total energy results indicate that the formation of MoS{sub 2}/HfO{sub 2} is an exothermic process with an adsorption energy of 34 meV/Å{sup 2}, which means that it is more stable than similar systems like graphene/HfO{sub 2} and MoS{sub 2}/SiO{sub 2}. There are no chemical bonds at the MoS{sub 2}-HfO{sub 2} interface. Upon formation of MoS{sub 2}/HfO{sub 2}, the electronic charge distribution is mostly localized at the interface region with no net charge transfer between the adsorbed MoS{sub 2} sheet and –HfO{sub 2} surface. However, the MoS{sub 2} sheet becomes n-type doped when there are oxygen vacancies in the HfO{sub 2} surface. Further investigation of the electronic distribution reveals that there are no electron- and hole-rich regions (electron-hole puddles) on the MoS{sub 2} sheet, which makes this system promising for use in high-speed nanoelectronic devices.

Human factoring administrative procedures

International Nuclear Information System (INIS)

Grider, D.A.; Sturdivant, M.H.

1991-01-01

In nonnuclear business, administrative procedures bring to mind such mundane topics as filing correspondence and scheduling vacation time. In the nuclear industry, on the other hand, administrative procedures play a vital role in assuring the safe operation of a facility. For some time now, industry focus has been on improving technical procedures. Significant efforts are under way to produce technical procedure requires that a validated technical, regulatory, and administrative basis be developed and that the technical process be established for each procedure. Producing usable technical procedures requires that procedure presentation be engineered to the same human factors principles used in control room design. The vital safety role of administrative procedures requires that they be just as sound, just a rigorously formulated, and documented as technical procedures. Procedure programs at the Tennessee Valley Authority and at Boston Edison's Pilgrim Station demonstrate that human factors engineering techniques can be applied effectively to technical procedures. With a few modifications, those same techniques can be used to produce more effective administrative procedures. Efforts are under way at the US Department of Energy Nuclear Weapons Complex and at some utilities (Boston Edison, for instance) to apply human factors engineering to administrative procedures: The techniques being adapted include the following

Crystallographic and magnetic property changes upon hydrogen absorption in Hf2Fe

International Nuclear Information System (INIS)

Vulliet, P.; Teisseron, G.; Jeandey, C.; Oddou, J.L.; Yaouanc, A.

1984-04-01

We have found that the cubic intermetallic compound Hf 2 Fe can absorb almost up to five hydrogen atoms per formula at a pressure of one atmosphere. Hf 2 Fe is a Pauli magnet. Upon hydrogen absorption a magnetic moment definitively appears on iron, starting at approximately 1.5 hydrogen concentration. A maximum in the saturation magnetic moment is observed in Hf 2 FeH 3 . The static low field susceptibility presents a maximum value and a non reversible behaviour. These properties are characteristic of a disordered magnetic system (spin-glass like). The γ-γ perturbed angular correlation spectra indicate that at low concentration, the hydrogen is localized only near one type of Hf. From our Moessbauer data we measure a shift in the isomer-shift which is consistent with what is already known. When decreasing the temperature and increasing the hydrogen concentration the spectra get less resolved. This is linked to the fact that the samples are in a disordered magnetic phase

Warranty claim analysis considering human factors

International Nuclear Information System (INIS)

Wu Shaomin

2011-01-01

Warranty claims are not always due to product failures. They can also be caused by two types of human factors. On the one hand, consumers might claim warranty due to misuse and/or failures caused by various human factors. Such claims might account for more than 10% of all reported claims. On the other hand, consumers might not be bothered to claim warranty for failed items that are still under warranty, or they may claim warranty after they have experienced several intermittent failures. These two types of human factors can affect warranty claim costs. However, research in this area has received rather little attention. In this paper, we propose three models to estimate the expected warranty cost when the two types of human factors are included. We consider two types of failures: intermittent and fatal failures, which might result in different claim patterns. Consumers might report claims after a fatal failure has occurred, and upon intermittent failures they might report claims after a number of failures have occurred. Numerical examples are given to validate the results derived.

Human factors in RBNK plants

International Nuclear Information System (INIS)

Demitrack, T.

1995-01-01

The Safety of RBMK nuclear power plants in the Russian Federation, The Ukraine and Lithuanian is a topic of concern to the European Union and other Western European countries. The European Commission, Sweden, Finland and Canada financed the project Safety Design Solutions and Operation of NPP with RBMK Reactors. The project examined nine issues and recommended safety improvements which will form the basis of future European Commission spending on these power plants. During its year of work, the project examined these issues: 1. Systems Engineering and progression of accidents 2. Protection System 3. Core Physics 4. External Events 5. Engineering Quality 6. Operating Experience 7. Human Factors 8. Regulatory Interface 9. Probabilistic Safety analysis Empresarios Agrupados, in collaboration with other western European firms, the Russian Federation and Lithuanian took part in two of these groups, Human Factors and Probabilistic Safety Analysis. This presentation gives a brief description of the most important aspects of human factors in RBMK plants, focusing on operations organization, training and education

40 CFR 180.1273 - Beauveria bassiana HF23; exemption from the requirement of a tolerance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Beauveria bassiana HF23; exemption... FOOD Exemptions From Tolerances § 180.1273 Beauveria bassiana HF23; exemption from the requirement of a tolerance. Residues of Beauveria bassiana HF23 are exempt from the requirement of a tolerance on all food...

Effect of HF leaching on {sup 14}C dates of pottery

Energy Technology Data Exchange (ETDEWEB)

Goslar, Tomasz, E-mail: goslar@radiocarbon.pl [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznan (Poland); Poznan Radiocarbon Laboratory, ul. Rubiez 46, 61-612 Poznan (Poland); Kozlowski, Janusz [Institute of Archaeology, Jagiellonian University, ul. Golebia 11, 30-007 Krakow (Poland); Szmyt, Marzena [Institute for Eastern Studies, Adam Mickiewicz University, ul. 28 Czerwca 1956 nr 198, 61-486 Poznan (Poland); Czernik, Justyna [Poznan Radiocarbon Laboratory, ul. Rubiez 46, 61-612 Poznan (Poland)

2013-01-15

This paper presents the experiments with {sup 14}C dating of two potsherds, which contained carbon dispersed rather homogeneously in their clay fabric. After AAA treatment, the potsherds still appeared to be contaminated with young carbon, presumably connected with humic acids. To make removal of humic acids more effective, we treated the sherds with HF acid of different concentration. The {sup 14}C results obtained demonstrate that HF treatment indeed helps to remove humic contaminants, but it also mobilizes carbon bound to raw clay, which may make {sup 14}C dates too old. We conclude therefore, that using a simple combination of HF and AAA treatment seems insufficient in reliable {sup 14}C dating of carbon homogeneously dispersed in the volume of potsherds.

Human factors with nonhumans - Factors that affect computer-task performance

Science.gov (United States)

Washburn, David A.

1992-01-01

There are two general strategies that may be employed for 'doing human factors research with nonhuman animals'. First, one may use the methods of traditional human factors investigations to examine the nonhuman animal-to-machine interface. Alternatively, one might use performance by nonhuman animals as a surrogate for or model of performance by a human operator. Each of these approaches is illustrated with data in the present review. Chronic ambient noise was found to have a significant but inconsequential effect on computer-task performance by rhesus monkeys (Macaca mulatta). Additional data supported the generality of findings such as these to humans, showing that rhesus monkeys are appropriate models of human psychomotor performance. It is argued that ultimately the interface between comparative psychology and technology will depend on the coordinated use of both strategies of investigation.

Modeling of NiTiHf using finite difference method

Science.gov (United States)

Farjam, Nazanin; Mehrabi, Reza; Karaca, Haluk; Mirzaeifar, Reza; Elahinia, Mohammad

2018-03-01

NiTiHf is a high temperature and high strength shape memory alloy with transformation temperatures above 100oC. A constitutive model based on Gibbs free energy is developed to predict the behavior of this material. Two different irrecoverable strains including transformation induced plastic strain (TRIP) and viscoplastic strain (VP) are considered when using high temperature shape memory alloys (HTSMAs). The first one happens during transformation at high levels of stress and the second one is related to the creep which is rate-dependent. The developed model is implemented for NiTiHf under uniaxial loading. Finite difference method is utilized to solve the proposed equations. The material parameters in the equations are calibrated from experimental data. Simulation results are captured to investigate the superelastic behavior of NiTiHf. The extracted results are compared with experimental tests of isobaric heating and cooling at different levels of stress and also superelastic tests at different levels of temperature. More results are generated to investigate the capability of the proposed model in the prediction of the irrecoverable strain after full transformation in HTSMAs.

Performance Analysis of HF Band FB-MC-SS

Energy Technology Data Exchange (ETDEWEB)

Hussein Moradi; Stephen Andrew Laraway; Behrouz Farhang-Boroujeny

2016-01-01

Abstract—In a recent paper [1] the filter bank multicarrier spread spectrum (FB-MC-SS) waveform was proposed for wideband spread spectrum HF communications. A significant benefit of this waveform is robustness against narrow and partial band interference. Simulation results in [1] demonstrated good performance in a wideband HF channel over a wide range of conditions. In this paper we present a theoretical analysis of the bit error probably for this system. Our analysis tailors the results from [2] where BER performance was analyzed for maximum ration combining systems that accounted for correlation between subcarriers and channel estimation error. Equations are give for BER that closely match the simulated performance in most situations.

Applications of human factors engineering in the digital HMI

International Nuclear Information System (INIS)

Zhou Bingjian

2014-01-01

In order to prevent and minimize human errors in the digital main control room, the principles of human factors engineering must be complied strictly in the design process of digital human-machine interface. This paper briefly describes the basic human factors engineering principles of designing main control room, introduces the main steps to implement the human factors engineering verification and validation of main control room, including HSI task support verification, human factors engineering design verification and integrated system validation. Meanwhile, according to the new digital human-machine interface characteristics, the development models of human error are analyzed. (author)

Effectiveness of human factors simulator; Eficiencia del simulador de factores humanos

Energy Technology Data Exchange (ETDEWEB)

Moragas, F.

2015-07-01

En 2011, ANAV started the exploitation of the Human Factors Simulator installed in TECNATOM Training Center located in L'Hospital de L'Infant Tarragona. AVAN's Strategic Plan includes the Action Plan for the improvement of human behavior. The plan includes improving the efficiency of the efficiency of the human factors simulator. It is proposed to improve the efficiency into two different terms: winning effectiveness in modeling behaviors, and interweaving the activities in the simulator with the actual strategy of promoting Safety culture and human behaviour. (Author)

Hf-Nd isotope decoupling in the oceanic lithosphere: constraints from spinel peridotites from Oahu, Hawaii

Science.gov (United States)

Bizimis, Michael; Sen, Gautam; Salters, Vincent J. M.

2004-01-01

We present a detailed geochemical investigation on the Hf, Nd and Sr isotope compositions and trace and major element contents of clinopyroxene mineral separates from spinel lherzolite xenoliths from the island of Oahu, Hawaii. These peridotites are believed to represent the depleted oceanic lithosphere beneath Oahu, which is a residue of a MORB-related melting event some 80-100 Ma ago at a mid-ocean ridge. Clinopyroxenes from peridotites from the Salt Lake Crater (SLC) show a large range of Hf isotopic compositions, from ɛHf=12.2 (similar to the Honolulu volcanics series) to extremely radiogenic, ɛHf=65, at nearly constant 143Nd/ 144Nd ratios ( ɛNd=7-8). None of these samples show any isotopic evidence for interaction with Koolau-type melts. A single xenolith from the Pali vent is the only sample with Hf and Nd isotopic compositions that falls within the MORB field. The Hf isotopes correlate positively with the degree of depletion in the clinopyroxene (e.g. increasing Mg#, Cr#, decreasing Ti and heavy REE contents), but also with increasing Zr and Hf depletions relative to the adjacent REE in a compatibility diagram. The Lu/Hf isotope systematics of the SLC clinopyroxenes define apparent ages of 500 Ma or older and these compositions cannot be explained by mixing between any type of Hawaiian melts and the depleted Pacific lithosphere. Metasomatism of an ancient (e.g. 1 Ga or older) depleted peridotite protolith can, in principle, explain these apparent ages and the Nd-Hf isotope decoupling, but requires that the most depleted samples were subject to the least amount of metasomatism. Alternatively, the combined isotope, trace and major element compositions of these clinopyroxenes are best described by metasomatism of the 80-100 Ma depleted oceanic lithosphere by melts products of extensive mantle-melt interaction between Honolulu Volcanics-type melts and the depleted lithosphere.

Mechanisms and selectivity for etching of HfO2 and Si in BCl3 plasmas

International Nuclear Information System (INIS)

Wang Chunyu; Donnelly, Vincent M.

2008-01-01

The authors have investigated plasma etching of HfO 2 , a high dielectric constant material, and poly-Si in BCl 3 plasmas. Etching rates were measured as a function of substrate temperature (T s ) at several source powers. Activation energies range from 0.2 to 1.0 kcal/mol for HfO 2 and from 0.8 to 1.8 kcal/mol for Si, with little or no dependence on source power (20-200 W). These low activation energies suggest that product removal is limited by chemical sputtering of the chemisorbed Hf or Si-containing layer, with a higher T s only modestly increasing the chemical sputtering rate. The slightly lower activation energy for HfO 2 results in a small improvement in selectivity over Si at low temperature. The surface layers formed on HfO 2 and Si after etching in BCl 3 plasmas were also investigated by vacuum-transfer x-ray photoelectron spectroscopy. A thin boron-containing layer was observed on partially etched HfO 2 and on poly-Si after etching through HfO 2 films. For HfO 2 , a single B(1s) feature at 194 eV was ascribed to a heavily oxidized species with bonding similar to B 2 O 3 . B(1s) features were observed for poly-Si surfaces at 187.6 eV (B bound to Si), 189.8 eV, and 193 eV (both ascribed to BO x Cl y ). In the presence of a deliberately added 0.5% air, the B-containing layer on HfO 2 is largely unaffected, while that on Si converts to a thick layer with a single B(1s) peak at 194 eV and an approximate stoichiometry of B 3 O 4 Cl

Interfacial microstructure of NiSi x/HfO2/SiO x/Si gate stacks

International Nuclear Information System (INIS)

Gribelyuk, M.A.; Cabral, C.; Gusev, E.P.; Narayanan, V.

2007-01-01

Integration of NiSi x based fully silicided metal gates with HfO 2 high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi x film. Ni content varies near the NiSi/HfO x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi x /HfO 2 interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi x /HfO x was found higher than that of poly-Si/HfO 2 , likely due to compositional non-uniformity of NiSi x . No intermixing between Hf, Ni and Si beyond interfacial roughness was observed

First demonstration of HF-driven ionospheric currents

Science.gov (United States)

Papadopoulos, K.; Chang, C.-L.; Labenski, J.; Wallace, T.

2011-10-01

The first experimental demonstration of HF driven currents in the ionosphere at low ELF/ULF frequencies without relying in the presence of electrojets is presented. The effect was predicted by theoretical/computational means in a recent letter and given the name Ionospheric Current Drive (ICD). The effect relies on modulated F-region HF heating to generate Magneto-Sonic (MS) waves that drive Hall currents when they reach the E-region. The Hall currents inject ELF waves into the Earth-Ionosphere waveguide and helicon and Shear Alfven (SA) waves in the magnetosphere. The proof-of-concept experiments were conducted using the HAARP heater in Alaska under the BRIOCHE program. Waves between 0.1-70 Hz were measured at both near and far sites. The letter discusses the differences between ICD generated waves and those relying on modulation of electrojets.

Investigation of the rotational nuclei 167168Hf and 170171W and the shell-model nucleus 26Mg

International Nuclear Information System (INIS)

Arciszewski, H.F.R.

1984-01-01

Two gamma-gamma coincidence experiments on neighbouring nuclei that exhibit the backbending phenomenon are described. The first experiment performed with the cyclotron of the KVI at Groningen is an investigation of 167 Hf and 168 Hf, whereas in the second experiment, performed at the cyclotron facility of Louvain University, high spin states are studied and compared with predictions of the cranked shell model. A new method for the correction of the large background of Compton-scattered events is described. Apart from this, an investigation of the single particle (d,p) transfer reaction at 26 Mg has been performed with the van de Graaff tandem accelerator at 14 MeV. Specroscopic factors are presented for many levels up to an excitation energy of 8 MeV. Several new spin assignments could be made. (Auth.)

Rare-earth-free luminescent non-stoichiometric phases formed in SrO-HfO.sub.2./sub. ternary compositions

Czech Academy of Sciences Publication Activity Database

Boháček, Pavel; Trunda, Bohumil; Beitlerová, Alena; Drahokoupil, Jan; Jarý, Vítězslav; Studnička, Václav; Nikl, Martin

2013-01-01

Roč. 580, Dec (2013), s. 468-474 ISSN 0925-8388 R&D Projects: GA AV ČR KAN300100802 Institutional support: RVO:68378271 Keywords : solid state sintering * nonstoichiometric phase * SrHfO3 * X-ray phosphor * luminescence Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.726, year: 2013

Human Reliability Analysis for Design: Using Reliability Methods for Human Factors Issues

Energy Technology Data Exchange (ETDEWEB)

Ronald Laurids Boring

2010-11-01

This paper reviews the application of human reliability analysis methods to human factors design issues. An application framework is sketched in which aspects of modeling typically found in human reliability analysis are used in a complementary fashion to the existing human factors phases of design and testing. The paper provides best achievable practices for design, testing, and modeling. Such best achievable practices may be used to evaluate and human system interface in the context of design safety certifications.

Human Reliability Analysis for Design: Using Reliability Methods for Human Factors Issues

International Nuclear Information System (INIS)

Boring, Ronald Laurids

2010-01-01

This paper reviews the application of human reliability analysis methods to human factors design issues. An application framework is sketched in which aspects of modeling typically found in human reliability analysis are used in a complementary fashion to the existing human factors phases of design and testing. The paper provides best achievable practices for design, testing, and modeling. Such best achievable practices may be used to evaluate and human system interface in the context of design safety certifications.

Effective moments of inertia and spin cut off parameters in Hf isotopes

International Nuclear Information System (INIS)

Razavi, R.; Sharifzadeh, N.; Farahmand, M.R.

2011-01-01

In all statistical theories the nuclear level density is the most characteristic quantity and plays a major role in the study of nuclear structure. Most experimental data on nuclear level density have been analyzed with analytical functions of the level density. On the basis of statistical models, the effective moments of inertia and spin cut off parameters have been determined for 176 Hf, 178 Hf and 180 Hf nuclei from extensive and complete level schemes and neutron resonance densities in low excitation energy levels. Then, moments of inertia of these nuclei have been determined by nuclear rotational model. The results have been compared with their corresponding rigid body value

Characterization of Hf/Mg co-doped ZnO thin films after thermal treatments

Energy Technology Data Exchange (ETDEWEB)

Li, Chih-Hung; Chung, Hantsun [Graduate Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan (China); Chen, Jian-Zhang, E-mail: jchen@ntu.edu.tw [Graduate Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan (China); Cheng, I-Chun, E-mail: iccheng@ntu.edu.tw [Graduate Institute of Photonics and Optoelectronics, Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2014-11-03

Rf-sputtered Mg{sub 0.05}Zn{sub 0.95}O thin films become amorphous/nanocrystalline with the addition of hafnium oxide. All films (thickness: ∼ 100 nm) sputter-deposited from Hf{sub x}Mg{sub 0.05}Zn{sub 0.95−x}O targets are highly transparent (> 80%) from 400 to 800 nm. The Tauc bandgap ΔE (eV) increases with the Hf content. However, the bandgap decreases after thermal treatment. The reduction in the bandgap is positively correlated with the Hf content and annealing temperature. The residual stresses of films sputtered from Mg{sub 0.05}Zn{sub 0.95}O and Hf{sub 0.025}Mg{sub 0.05}Zn{sub 0.925}O targets are determined based on X-ray diffraction (XRD) data using a bi-axial stress model. The residual stresses of as-deposited films are compressive. As the annealing temperature increases, the residual stresses are relaxed and even become tensile. The bandgap narrowing after thermal treatment is attributed to the stress relaxation that changes the repulsion between the oxygen 2p and zinc 4s bands. Slight grain growth may also result in bandgap reduction because bandgap modification caused by the quantum confinement effect becomes significant in amorphous/nanocrystalline materials. The amorphous thin films reveal good thermal stability after 600 °C annealing for up to 2 h, as evidenced by the XRD and transmission spectra. - Highlights: • Thin films are sputtered from Hf{sub x}Mg{sub 0.05}Zn{sub 0.95−x}O targets at room temperature. • Bandgap increases with Hf content but decreases with post-annealing temperature. • Bandgap narrowing after annealing partly results from the relaxation of stresses. • Bandgap narrowing partly results from quantum confinement effect by nanomaterials. • Hf doping increases resistivity due to the lattice disorder and enlarged bandgap.

US Nuclear Regulatory Commission human-factors program plan

International Nuclear Information System (INIS)

1983-08-01

The purpose of the NRC Human Factors Program Plan is to ensure that proper consideration is given to human factors in the design, operation, and maintenance of nuclear facilities. This initial plan addresses nuclear power plants (NPP) and describes (1) the technical assistance and research activities planned to provide the technical bases for the resolution of the remaining human factors related tasks described in NUREG-0660, The NRC Action Plan Developed as a Result of the TMI-2 Accident, and NUREG-0737, Clarification of TMI Action Plan Requirements, and (2) the additional human factors efforts identified during implementation of the Action Plan that should receive NRC attention. The plan represents a systematic and comprehensive approach for addressing human factors concerns important to NPP safety in the FY-83 through FY-85 time frame

Human factors in aviation

National Research Council Canada - National Science Library

Salas, Eduardo; Maurino, Daniel E

2010-01-01

.... HFA offers a comprehensive overview of the topic, taking readers from the general to the specific, first covering broad issues, then the more specific topics of pilot performance, human factors...

Electronic and magnetic properties of 1T-HfS{sub 2} by doping transition-metal atoms

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xu, E-mail: zhaoxu@htu.cn [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Wang, Tianxing; Wang, Guangtao [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Dai, Xianqi [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Department of Physics, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Xia, Congxin [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Yang, Lin [School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007 (China)

2016-10-15

Highlights: • Pristine 1T-HfS{sub 2} is a semiconductor with indirect gaps of 1.250 eV • Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. • Strong p–d hybridization was found between TM 3d orbitals and S 3p orbitals. • V-doped 1T-HfS{sub 2} is ideal for spin injection. - Abstract: We explored the electronic and magnetic properties of 1T-HfS{sub 2} doped by transition metal (TM) atom using the first-principles calculation. We doped the transition metal atoms from the IIIB to VIB groups in nonmagnetic 1T-HfS{sub 2}. Numerical results show that the pristine 1T-HfS{sub 2} is a semiconductor with indirect gaps of 1.250 eV. Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. The polarized charges mainly arise from the localized 3d electrons of the TM atom. The strong p–d hybridization was found between the 3d orbitals of TM and 3p orbitals of S. The substituted 1T-HfS{sub 2} can be a metal, semiconductor or half-metal. Analysis of the band structure and magnetic properties indicates that TM-doped HfS{sub 2} (TM = V, Fe, Cu) are promising systems to explore two-dimensional diluted magnetic semiconductors. The formation energy calculations also indicate that it is energetically favorable and relatively easier to incorporate transition metal atom into the HfS{sub 2} under S-rich experimental conditions. In contrast, V-doped HfS{sub 2} has relatively wide half-metallic gap and low formation energy. So V-doped 1T-HfS{sub 2} is ideal for spin injection, which is important for application in semiconductor spintronics.

HF treatment effect for carbon deposition on silicon (111) by DC sputtering technique

Energy Technology Data Exchange (ETDEWEB)

Aji, A. S., E-mail: aji.ravazes70@gmail.com; Darma, Y., E-mail: aji.ravazes70@gmail.com [Quantum Semiconductor and Devices Lab., Physics of Material Electronics Research Division, Department of Physics, Institut Teknologi Bandung (Indonesia)

2014-03-24

Surface modifications of Si (111) substrate by HF solution for thin film carbon deposition have been systematically studied. Thin film carbon on Si (111) has been deposited using DC Unbalanced Magnetron Sputtering with carbon pellet doped by 5% Fe as the target. EDAX characterization confirmed that the carbon fraction on Si substrate much higher by dipping a clean Si substrate by HF solution before sputtering process in comparison with carbon fraction on Si substrate just after conventional RCA. Moreover, SEM and AFM images show the uniform thin film carbon on Si with HF treatment, in contrast to the Si without HF solution treatment. These experimental results suggest that HF treatment of Si surface provide Si-H bonds on top Si surface that useful to enhance the carbon deposition during sputtering process. Furthermore, we investigate the thermal stability of thin film carbon on Si by thermal annealing process up to 900 °C. Atomic arrangements during annealing process were characterized by Raman spectroscopy. Raman spectra indicate that thin film carbon on Si is remaining unchanged until 600 °C and carbon atoms start to diffuse toward Si substrate after annealing at 900 °C.

Human factors methods for nuclear control room design. Volume 2. Human factors survey of control room design practices

International Nuclear Information System (INIS)

Seminara, J.L.; Parsons, S.O.

1979-11-01

An earlier review of the control rooms of operating nuclear power plants identified many design problems having potential for degrading operator performance. As a result, the formal application of human factors principles was found to be needed. This report demonstrates the use of human factors in the design of power plant control rooms. The approaches shown in the report can be applied to operating power plants, as well as to those in the design stage. This study documents human factors techniques required to provide a sustained concern for the man-machine interface from control room concept definition to system implementation

The importance of residues 195-206 of human blood clotting factor VII in the interaction of factor VII with tissue factor

International Nuclear Information System (INIS)

Wildgoose, P.; Kisiel, W.; Kazim, A.L.

1990-01-01

Previous studies indicated that human and bovine factor VII exhibit 71% amino acid sequence identity. In the present study, competition binding experiments revealed that the interaction of human factor VII with cell-surface human tissue factor was not inhibited by 100-fold molar excess of bovine factor VII. This finding indicated that bovine and human factor VII are not structurally homologous in the region(s) where human factor VII interacts with human tissue factor. On this premise, the authors synthesized three peptides corresponding to regions of human factor VII that exhibited marked structural dissimilarity to bovine factor VII; these regions of dissimilarity included residues 195-206, 263-274, and 314-326. Peptide 195-206 inhibited the interaction of factor VII with cell-surface tissue factor and the activation of factor X by a complex of factor VIIa and tissue factor half-maximally at concentrations of 1-2 mM. A structurally rearranged form of peptide 195-206 containing an aspartimide residue inhibited these reactions half-maximally at concentrations of 250-300 μM. In contrast, neither peptide 263-274 nor peptide 314-326, at 2 mM concentration, significantly affected either factor VIIa interaction with tissue factor or factor VIIa-mediated activation of factor X. The data provide presumptive evidence that residues 195-206 of human factor VII are involved in the interaction of human factor VII with the extracellular domain of human tissue factor apoprotein

A FORMAÇÃO DE LIGAÇÕES DE HIDROGÊNIO π‧‧‧H, F‧‧‧H E C‧‧‧H NOS COMPLEXOS C2H2‧‧‧(HF, C2H2‧‧‧2(HF E C2H2‧‧‧3(HF

Directory of Open Access Journals (Sweden)

Boaz G. Oliveira

2016-04-01

Full Text Available In this work, a theoretical study on the basis of structural, vibrational, electronic and topological parameters of the C2H2‧‧‧(HF, C2H2‧‧‧2(HF and C2H2‧‧‧3(HF complexes concerning the formation of π‧‧‧H, F‧‧‧H and C‧‧‧H hydrogen bonds is presented. The main difference among these complexes is not properly the interaction strength, but the hydrogen bond type whose benchmark is ruled justly by the structure. Meanwhile, the occurrence of π‧‧‧H hydrogen bonds was unveiled in both C2H2‧‧‧(HF dimer and C2H2‧‧‧3(HF tetramer, although in latter, this interaction is stronger than C‧‧‧H of the C2H2‧‧‧2(HF trimer. However, the F‧‧‧H hydrogen bonds within the subunits of hydrofluoric acid are the strongest ones, reaching a partial covalent limit, and thereby contribute decisively to the stabilization of the tetramer structure. In line with this, the largest red-shifts were observed on the hydrofluoric acid trimer of the C2H2‧‧‧3(HF complex.

Effect of ozone treatment on the optical and electrical properties of HfSiO thin films

International Nuclear Information System (INIS)

Geng, Yang; Yang, Wen; Zhu, Shang-Bin; Zhang, Yuan; Sun, Qing-Qing; Lu, Hong-Liang; Zhang, David Wei

2014-01-01

The effect of room temperature ozone oxidation treatment on thin HfSiO film grown by atomic layer deposition (ALD) has been investigated. The optical and electrical properties with different post-ozone oxidation time were characterized. The evolution of ozone interacting with HfSiO films was clearly illuminated. Ozone can repair the lossy chemical bonds and vacancies, resulting in the improvement of packing density and polarizability of HfSiO films. With more ozone entering the HfSiO films, the refractive index, dielectric constant, and interfacial properties can be greatly upgraded. Furthermore, the frequency dispersion of ALD-HfSiO film can be improved after O 3 treatment time for 8 min. (orig.)

Numeric modeling of HfO2 neutron flux sensor parameters during sensor burnup in the RBMK-1500 reactor

International Nuclear Information System (INIS)

Jurkevicius, A.; Remeikis, V.

2001-01-01

The isotopic composition of hafnium in the radial neutron flux sensor of the RBMK-1500 reactor, the rates of the neutron absorption on Hf isotopes and the neutron spectrum in the sensor were numerically modeled. The sequence SAS2 (Shielding Analysis Sequence) from the package SCALE 4.3 was used for calculations. It has been obtained that the main neutron absorber 167 Er isotope practically burns up completely at the 18 MW d/kgU burnup depth, and at that time the capture rate of thermal neutrons in erbium decreases ten-fold. The average neutron flux density was calculated 7.6*10 13 neutrons. Cm -2 S -1 in the RBMK-1500 reactor grating, when the nuclear fuel enriched with 235 U by 2.4% and with Er by 0.4% is used in a fuel assembly. When the sensor burnup reaches 28 MW d/kgU, the neutron absorption rate of 178 Hf exceeds the rate of 177 Hf. The overall neutron absorption rate in hafnium decreases 2.53 times due to the sensor burnup to 56 MW d/kgU. The corrective factors ξ d (I) at different integral flux I of the sensors were calculated. The obtained dependence ξ d (I) calculated numerically was compared to the experimental one determined by processing repeated calibration results of Hf sensors in RBMK-1500 reactors, as well as compared to the theoretical one currently used in the Ignalina NPP special mathematical algorithms. (author)

Deep electron traps in HfO_2-based metal-oxide-semiconductor capacitors

International Nuclear Information System (INIS)

Salomone, L. Sambuco; Lipovetzky, J.; Carbonetto, S.H.; García Inza, M.A.; Redin, E.G.; Campabadal, F.

2016-01-01

Hafnium oxide (HfO_2) is currently considered to be a good candidate to take part as a component in charge-trapping nonvolatile memories. In this work, the electric field and time dependences of the electron trapping/detrapping processes are studied through a constant capacitance voltage transient technique on metal-oxide-semiconductor capacitors with atomic layer deposited HfO_2 as insulating layer. A tunneling-based model is proposed to reproduce the experimental results, obtaining fair agreement between experiments and simulations. From the fitting procedure, a band of defects is identified, located in the first 1.7 nm from the Si/HfO_2 interface at an energy level E_t = 1.59 eV below the HfO_2 conduction band edge with density N_t = 1.36 × 10"1"9 cm"−"3. A simplified analytical version of the model is proposed in order to ease the fitting procedure for the low applied voltage case considered in this work. - Highlights: • We characterized deep electron trapping/detrapping in HfO_2 structures. • We modeled the experimental results through a tunneling-based model. • We obtained an electron trap energy level of 1.59 eV below conduction band edge. • We obtained a spatial trap distribution extending 1.7 nm within the insulator. • A simplified tunneling front model is able to reproduce the experimental results.

On the stabilization of NbV-solutions by ZrIV and HfIV

International Nuclear Information System (INIS)

Soerensen, E.; Bjerre, A.B.

1987-11-01

Niobium cannot be separated from zirconium or hafnium when these elements occur together in solution with common anions such as Cl- and SO 4 --. This is ascribed to the copolymerisation of Nb v and the hydrolyzed ionic species of Zr IV v and Hf IV by which the colloidal particles are masked as Zr- and Hf-compounds. In HCl the particles are positively charged as opposed to when they are in sulphate solution where the Zr- and Hf- sulphate complexes confer a negative charge. The two cases are considered separately. (author)

Meeting Human Reliability Requirements through Human Factors Design, Testing, and Modeling

Energy Technology Data Exchange (ETDEWEB)

R. L. Boring

2007-06-01

In the design of novel systems, it is important for the human factors engineer to work in parallel with the human reliability analyst to arrive at the safest achievable design that meets design team safety goals and certification or regulatory requirements. This paper introduces the System Development Safety Triptych, a checklist of considerations for the interplay of human factors and human reliability through design, testing, and modeling in product development. This paper also explores three phases of safe system development, corresponding to the conception, design, and implementation of a system.

Importance of human factors on nuclear installations safety

International Nuclear Information System (INIS)

Caruso, G.J.

1990-01-01

Actually, installations safety and, in particular the nuclear installations infer a strong incidence in human factors related to the design and operation of such installations. In general, the experience aims to that the most important accidents have happened as result of the components' failures combination and human failures in the operation of safety systems. Human factors in the nuclear installations may be divided into two areas: economy and human reliability. Human factors treatments for the safety evaluation of the nuclear installations allow to diagnose the weak points of man-machine interaction. (Author) [es

Difference in Thermal Degradation Behavior of ZrO2 and HfO2 Anodized Capacitors

Science.gov (United States)

Kamijyo, Masahiro; Onozuka, Tomotake; Yoshida, Naoto; Shinkai, Satoko; Sasaki, Katsutaka; Yamane, Misao; Abe, Yoshio

2004-09-01

Microcrystalline ZrO2 and HfO2 thin film capacitors were prepared by anodizing sputter-deposited Zr and Hf films. The thermal degradation behavior of both anodized capacitors was clarified by the measurement of their capacitance properties and Auger depth profiles before and after heat treatment in air. As a result, it is confirmed that the heat-resistance property of the HfO2 anodized capacitor is superior to that of the ZrO2 capacitor. In addition, it is revealed that the thermal degradation of the ZrO2 anodized capacitor is caused by the diffusion of Zr atoms from the underlying layer into the ZrO2 anodized layer, while that of the HfO2 anodized capacitor is caused by the diffusion of oxygen atoms from the anodized layer into the underlying Hf layer.

Pulsed laser deposition of HfO{sub 2} thin films on indium zinc oxide: Band offsets measurements

Energy Technology Data Exchange (ETDEWEB)

Craciun, D.; Craciun, V., E-mail: valentin.craciun@inflpr.ro

2017-04-01

Highlights: • High quality amorphous IZO and HfO{sub 2} films were obtained by PLD technique. • XPS measurements were used to obtain the valence band alignment in HfO{sub 2}/IZO heterostructure. • A valence band offset (ΔE{sub V}) of 1.75 eV was obtained for the HfO{sub 2}/IZO heterostructure. • A conduction band offset (ΔE{sub C}) of 0.65 eV was estimated for the HfO{sub 2}/IZO heterostructure. - Abstract: One of the most used dielectric films for amorphous indium zinc oxide (IZO) based thin films transistor is HfO{sub 2}. The estimation of the valence band discontinuity (ΔE{sub V}) of HfO{sub 2}/IZO heterostructure grown using the pulsed laser deposition technique, with In/(In + Zn) = 0.79, was obtained from X-ray photoelectron spectroscopy (XPS) measurements. The binding energies of Hf 4d5, Zn 2p3 and In 3d5 core levels and valence band maxima were measured for thick pure films and for a very thin HfO{sub 2} film deposited on a thick IZO film. A value of ΔE{sub V} = 1.75 ± 0.05 eV was estimated for the heterostructure. Taking into account the measured HfO{sub 2} and IZO optical bandgap values of 5.50 eV and 3.10 eV, respectively, a conduction band offset ΔE{sub C} = 0.65 ± 0.05 eV in HfO{sub 2}/IZO heterostructure was then obtained.

Nanomechanical study of amorphous and polycrystalline ALD HfO2 thin films

Science.gov (United States)

K. Tapily; J.E. Jakes; D. Gu; H. Baumgart; A.A. Elmustafa

2011-01-01

Thin films of hafnium oxide (HfO2) were deposited by atomic layer deposition (ALD). The structural properties of the deposited films were characterised by transmission electron microscopy (TEM) and X-ray diffraction (XRD). We investigated the effect of phase transformations induced by thermal treatments on the mechanical properties of ALD HfO

Human factors methods for nuclear control room design. Volume I. Human factors enhancement of existing nuclear control rooms. Final report

International Nuclear Information System (INIS)

Seminara, J.L.; Seidenstein, S.; Eckert, S.K.; Smith, D.L.

1979-11-01

Human factors engineering is an interdisciplinary specialty concerned with influencing the design of equipment systems, facilities, and operational environments to promote safe, efficient, and reliable operator performance. Human factors approaches were applied in the design of representative nuclear power plant control panels. First, methods for upgrading existing operational control panels were examined. Then, based on detailed human factors analyses of operator information and control requirements, designs of reactor, feedwater, and turbine-generator control panels were developed to improve the operator-control board interface, thereby reducing the potential for operator errors. In addition to examining present-generation concepts, human factors aspects of advanced systems and of hybrid combinations of advanced and conventional designs were investigated. Special attention was given to warning system designs. Also, a survey was conducted among control board designers to (1) develop an overview of design practices in the industry, and (2) establish appropriate measures leading to a more systematic concern for human factors in control board design

Human Factors Interface with Systems Engineering for NASA Human Spaceflights

Science.gov (United States)

Wong, Douglas T.

2009-01-01

This paper summarizes the past and present successes of the Habitability and Human Factors Branch (HHFB) at NASA Johnson Space Center s Space Life Sciences Directorate (SLSD) in including the Human-As-A-System (HAAS) model in many NASA programs and what steps to be taken to integrate the Human-Centered Design Philosophy (HCDP) into NASA s Systems Engineering (SE) process. The HAAS model stresses systems are ultimately designed for the humans; the humans should therefore be considered as a system within the systems. Therefore, the model places strong emphasis on human factors engineering. Since 1987, the HHFB has been engaging with many major NASA programs with much success. The HHFB helped create the NASA Standard 3000 (a human factors engineering practice guide) and the Human Systems Integration Requirements document. These efforts resulted in the HAAS model being included in many NASA programs. As an example, the HAAS model has been successfully introduced into the programmatic and systems engineering structures of the International Space Station Program (ISSP). Success in the ISSP caused other NASA programs to recognize the importance of the HAAS concept. Also due to this success, the HHFB helped update NASA s Systems Engineering Handbook in December 2007 to include HAAS as a recommended practice. Nonetheless, the HAAS model has yet to become an integral part of the NASA SE process. Besides continuing in integrating HAAS into current and future NASA programs, the HHFB will investigate incorporating the Human-Centered Design Philosophy (HCDP) into the NASA SE Handbook. The HCDP goes further than the HAAS model by emphasizing a holistic and iterative human-centered systems design concept.

Dosimetry of ultraviolet radiation with BaHfO_3 powders

International Nuclear Information System (INIS)

Barrera A, A. A.; Aguilar D, G. A.; Guzman M, J.; Rivera M, T.; Ceron R, V.

2016-10-01

Ceramic materials based on pure barium hafnate (BaHfO_3) have been obtained as a powder by the co-precipitation method. The powders obtained have a cubic structure that favors the thermoluminescent and optical properties, through which a better detection of the non-ionizing radiation is allowed. With these powders various tests were performed in the ultraviolet range at different exposure times. These thermoluminescent (Tl) studies were carried out using a Tl 3500 hand held reader which yielded a brightness curve that ranged from room temperature to the 350 degrees Celsius. This BaHfO_3 response exhibits a broad brightness curve with a single peak centered around 225 degrees Celsius. Finally, is reported that there are materials of barium hafnate (BaHfO_3) doped with some rare earths (Eu, Tb) which, instead of improving the performance of the powders, decrease it, so that the use of intrinsic barium hafnate is the most appropriate. (Author)

Solution Structure of Enterocin HF, an Antilisterial Bacteriocin Produced by Enterococcus faecium M3K31.

Science.gov (United States)

Arbulu, Sara; Lohans, Christopher T; van Belkum, Marco J; Cintas, Luis M; Herranz, Carmen; Vederas, John C; Hernández, Pablo E

2015-12-16

The solution structure of enterocin HF (EntHF), a class IIa bacteriocin of 43 amino acids produced by Enterococcus faecium M3K31, was evaluated by CD and NMR spectroscopy. Purified EntHF was unstructured in water, but CD analysis supports that EntHF adopts an α-helical conformation when exposed to increasing concentrations of trifluoroethanol. Furthermore, NMR spectroscopy indicates that this bacteriocin adopts an antiparallel β-sheet structure in the N-terminal region (residues 1-17), followed by a well-defined central α-helix (residues 19-30) and a more disordered C-terminal end (residues 31-43). EntHF could be structurally organized into three flexible regions that might act in a coordinated manner. This is in agreement with the absence of long-range nuclear Overhauser effect signals between the β-sheet domain and the C-terminal end of the bacteriocin. The 3D structure recorded for EntHF fits emerging facts regarding target recognition and mode of action of class IIa bacteriocins.

Highly ordered nanotubular film formation on Ti–25Nb–xZr and Ti–25Ta–xHf

Energy Technology Data Exchange (ETDEWEB)

Kim, Jeong-Jae; Byeon, In-Seop [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials, & Research Center for Oral Disease Regulation of the Aged, College of Dentistry, Chosun University, Gwangju (Korea, Republic of); Brantley, William A. [Division of Restorative Sciences and Prosthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials, & Research Center for Oral Disease Regulation of the Aged, College of Dentistry, Chosun University, Gwangju (Korea, Republic of)

2015-12-01

The purpose of this study was to investigate the highly ordered nanotubular film formation on Ti–25Nb–xZr and Ti–25Ta–xHf, examining the roles of niobium, zirconium, tantalum and hafnium alloying elements. The Ti–25Nb–xZr and Ti–25Ta–xHf ternary alloys contained 0, 7 and 15 wt.% of these alloying elements and were manufactured using a vacuum arc-melting furnace. Cast ingots of the alloys were homogenized in Ar atmosphere at 1050 °C for 2 h, followed by quenching into ice water. Formation of nanotubular films was achieved by an electrochemical method in 1 M H{sub 3}PO{sub 4} + 0.8 wt.% NaF at 30 V and 1 h for the Ti–25Nb–xZr alloys and 2 h for the Ti–25Ta–xHf alloys. Microstructures of the Ti–25Ta–xHf alloys transformed from α″ phase to β phase, changing from a needle-like structure to an equiaxed structure as the Hf content increased. In a similar manner, the needle-like structure of the Ti–25Nb–xZr alloys transformed to an equiaxed structure as the Zr content increased. Highly ordered nanotubes formed on the Ti–25Ta–15Hf and Ti–25Nb–15Zr alloys compared to the other alloys, and the nanotube layer thickness on Ti–25Ta–15Hf and Ti–25Nb–15Zr was greater than for the other alloys. Nanotubes formed on Ti–25Ta–15Hf and Ti–25Nb–15Zr showed two sizes of highly ordered structures. The diameters of the large nanotubes decreased and the diameters of the small nanotubes increased as Zr and Hf contents increased. It was found that the layer thickness, diameter, surface density and growth rate of nanotubes on the Ti–25Ta–xHf and Ti–25Nb–xZr alloys can be controlled by varying the Hf and Zr contents. X-ray diffraction analyses revealed only weak peaks for crystalline anatase or rutile TiO{sub 2} phases from the nanotubes on the Ti–25Nb–xZr and Ti–25Ta–xHf alloys, indicating a largely amorphous condition. - Highlights: • Nanotubular film formation on anodized Ti-25Nb-xZr and Ti-25Ta-xHf (x = 0, 7 and

A new potential energy surface for vibration-vibration coupling in HF-HF collisions. Formulation and quantal scattering calculations

Science.gov (United States)

Schwenke, David W.; Truhlar, Donald G.

1988-04-01

We present new ab initio calculations of the HF-HF interaction potential for the case where both molecules are simultaneously displaced from their equilibrium internuclear distance. These and previous ab initio calculations are then fit to a new analytic representation which is designed to be efficient to evaluate and to provide an especially faithful account of the forces along the vibrational coordinates. We use the new potential for two sets of quantal scattering calculations for collisions in three dimensions with total angular momentum zero. First we test that the angular harmonic representation of the anisotropy is adequate by comparing quantal rigid rotator calculations to those carried out for potentials involving higher angular harmonics and for which the expansion in angular harmonics is systematically increased to convergence. Then we carry out large-scale quantal calculations of vibration-vibration energy transfer including the coupling of both sets of vibrational and rotational coordinates. These calculations indicate that significant rotational energy transfer accompanies the vibration-to-vibration energy transfer process.

Human factors in the Canadian nuclear industry: future needs

International Nuclear Information System (INIS)

Harrison, F.

2008-01-01

Currently the industry is facing refurbishment and new builds. At present most licensees in Canada do not have sufficient numbers of Human Factors staff. As a result, the activities of the CNSC are too often focused on providing guidance regarding the application of Human Factors, in addition to reviewing work submitted by the licensee. Greater efficiencies for both the licensee and the CNSC could be realized if licensee staff had greater Human Factors expertise. Strategies for developing Human Factors expertise should be explored through cooperative partnerships with universities, which could be encouraged to include Human Factors courses specific to nuclear. (author)

Closed cycle high-repetition-rate pulsed HF laser

Science.gov (United States)

Harris, Michael R.; Morris, A. V.; Gorton, Eric K.

1997-04-01

The design and performance of a closed cycle high repetition rate HF laser is described. A short pulse, glow discharge is formed in a 10 SF6:1 H2 gas mixture at a total pressure of approximately 110 torr within a 15 by 0.5 by 0.5 cm3 volume. Transverse, recirculated gas flow adequate to enable repetitive operation up to 3 kHz is imposed by a centrifugal fan. The fan also forces the gas through a scrubber cell to eliminate ground state HF from the gas stream. An automated gas make-up system replenishes spent gas removed by the scrubber. Typical mean laser output powers up to 3 W can be maintained for extended periods of operation.

Antioxidant mechanism of black garlic extract involving nuclear factor erythroid 2-like factor 2 pathway.

Science.gov (United States)

Ha, Ae Wha; Kim, Woo Kyoung

2017-06-01

Although studies have revealed that black garlic is a potent antioxidant, its antioxidant mechanism remains unclear. The objective of this study was to determine black garlic's antioxidant activities and possible antioxidant mechanisms related to nuclear factor erythroid 2-like factor 2 (Nrf2)-Keap1 complex. After four weeks of feeding rats with a normal fat diet (NF), a high-fat diet (HF), a high-fat diet with 0.5% black garlic extract (HF+BGE 0.5), a high-fat diet with 1.0% black garlic extract (HF+BGE 1.0), or a high-fat diet with 1.5% black garlic extract (HF+BGE 1.5), plasma concentrations of glucose, insulin,homeostatic model assessment of insulin resistance (HOMA-IR) were determined. As oxidative stress indices, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and 8-isoprostaglandin F2α (8-iso-PGF) were determined. To measure antioxidant capacities, plasma total antioxidant capacity (TAC) and activities of antioxidant enzymes in plasma and liver were determined. The mRNA expression levels of antioxidant related proteins such as Nrf2, NAD(P)H: quinone-oxidoreductase-1 (NQO1), heme oxygenase-1 (HO-1), glutathione reductase (GR), and glutathione S-transferase alpha 2 (GSTA2) were examined. Plasma glucose level, plasma insulin level, and HOMA-IR in black garlic supplemented groups were significantly ( P concentration and TAC in the HF+BGE 1.5 group were significantly decreased compared to those of the HF group. The activities of catalase and glutathione peroxidase were significantly ( P antioxidant systems in rats fed with black garlic extract were related to mRNA expression levels of Nrf2 related genes.

Electrochemical etching of a niobium foil in methanolic HF for electrolytic capacitor

International Nuclear Information System (INIS)

Kim, Kyungmin; Park, Jiyoung; Cha, Gihoon; Yoo, Jeong Eun; Choi, Jinsub

2013-01-01

Electrochemical etching of niobium foil in order to enlarge the surface area for the application in electrolytic capacitor was carried out in a methanolic electrolyte. We found that the pit density and depth are not linearly proportional to concentration of HF and applied potential: there is the optimal concentration of HF at each applied potential. The optimal etching condition was obtained at 50 V in 0.99 vol.% HF, which exhibited the capacitance of 350 μF cm −2 . Pit density and depth of pits on electrochemical etched Nb foil under different conditions were counted from SEM images and electrochemical impedance spectroscopy (EIS) of the etched Nb foils was carried out for the capacitance measurement. Equivalent circuit model showing less than 5% error was suggested for applying to the etched niobium foil. - Highlights: • Surface enlargement of Nb foil can be achieved by electrochemical etching in methanolic HF. • Electrolytic capacitor of etched niobium foil exhibits a capacitance of 350 μF cm −2 . • The method provides a way of developing commercially viable process

Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

Energy Technology Data Exchange (ETDEWEB)

Agraval, Pavel; Turchanin, Mikhail [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Dreval, Liya [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Materials Science International Services GmbH (MSI), Stuttgart (Germany)

2016-12-15

In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x{sub Cu}/x{sub Fe} = 3/1, 1/1 at x{sub Hf} = 0-0.47 and along the section x{sub Cu}/x{sub Fe} = 1/3 at x{sub Hf} = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ{sub mix} anti H{sub Hf}{sup ∞}, are (-122 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 3/1), (-106 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/1), and (-105 ± 2) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.

Raman scattering from epitaxial HfN layers grown on MgO(001)

International Nuclear Information System (INIS)

Stoehr, M.; Seo, H.-S.; Petrov, I.; Greene, J.E.

2006-01-01

Stoichiometric single-crystal HfN layers grown on MgO(001) are analyzed by Raman spectroscopy. Second-order Raman scattering predominates, but first-order modes in the acoustic and optical ranges are also visible. The latter indicates that the O h symmetry of NaCl-structure HfN is broken. The large mass difference between Hf and N leads to a correspondingly large separation, 250 cm -1 , between the first-order acoustic and optical bands. Within this gap, four Raman lines are clearly observed. The first three are the second-order transverse acoustic mode (240 cm -1 ), the sum of the first-order transverse and longitudinal acoustic modes (280 cm -1 ), and the second-order longitudinal acoustic mode (325 cm -1 ). The fourth line at 380 cm -1 is identified as the difference between the first-order optical and acoustic modes. The observed first-order Raman scattering, as well as the width of the gap between the first-order acoustic and optical modes, is in good agreement with previously calculated HfN phonon density of states

A framework for human factors

International Nuclear Information System (INIS)

Webb, R.D.G.

As the complexity of industrial systems increases, the need for efficient integration of human beings into the systems that they design and operate grows more important. Human factors, or ergonomics, is concerned with the application of life science knowledge about human characteristics to maximise performance and well-being in any context. The most complex problem is to identify job demands in terms of different human dimensions and to apply established life science knowledge to determine optimum solutions. This requires the cooperation of many specialists

A Forming-Free Bipolar Resistive Switching in HfOx-Based Memory with a Thin Ti Cap

Science.gov (United States)

Pang, Hua; Deng, Ning

2014-10-01

The electroforming process of Ti/HfOx stacked RRAM devices is removed via the combination of low temperature atomic layer deposition and post metal annealing. The Pt/Ti/HfOx/Pt RRAM devices show a forming-free bipolar resistive switching behavior. By x-ray photoelectron emission spectroscopy analysis, it is found that there are many oxygen vacancies and nonlattice oxygen pre-existing in the HfOx layer that play a key role in removing the electroforming process. In addition, when the thickness ratio of the Ti and HfOx layer is 1, the uniformity of the switching parameters of Pt/Ti/HfOx/Pt devices is significantly improved. The OFF/ON window maintains about 100 at the read voltage of 0.1 V.

HF Surface Wave Radar Operation in Adverse Conditions

National Research Council Canada - National Science Library

Ponsford, Anthony M; Dizaji, Reza M; McKerracher, Richard

2005-01-01

...) system based on HF Surface Wave Radar (HFSWR). the primary objective behind the programme was to demonstrate the capability of HFSWR to continuously detect and track surface targets (ships and icebergs...

Study of the properties of internal oxidized Cu - Al - Ti - Hf alloys

International Nuclear Information System (INIS)

Solopov, V.I.; Daneliya, E.P.; Daneliya, G.V.; Lebasova, O.P.

1982-01-01

Investigation results of mechanical properties and electric conductivity of rods of internally oxidized alloys Cu-Al-Ti-Hf depending on chemical composition, varying in the limits ensuring the formation of disperse enough and evenly distributed over the volume oxide phase. (0-1%Al, 0-0.5%Ti, 0-0.3%Hf, the restcopper), in the process of internal oxidation are presented. Internally oxidized alloys Cu-Al-Ti-Hf have increased strength properties with insignificant increase of specific electric resistance as compared with the known internally oxidized alloys Cu-Al. At that, the best combination of physicomechanical properties is achieved at small contents of titanium (0.01-0.05%) and hafnium (0.01-0.1%)

Effect of oxide charge trapping on x-ray photoelectron spectroscopy of HfO2/SiO2/Si structures

International Nuclear Information System (INIS)

Abe, Yasuhiro; Miyata, Noriyuki; Suzuki, Haruhiko; Kitamura, Koji; Igarashi, Satoru; Nohira, Hiroshi; Ikenaga, Eiji

2009-01-01

We examined the effects of interfacial SiO 2 layers and a surface metal layer on the photoelectron spectra of HfO 2 /SiO 2 /Si structures by hard X-ray photoemission spectroscopy with synchrotron radiation as well as conventional X-ray photoelectron spectroscopy (XPS). The Hf 4f and Hf 3d photoelectron peaks broadened and shifted toward a higher binding energy with increasing thickness of the interfacial SiO 2 layer, even though photoelectrons may have been emitted from the HfO 2 layer with the same chemical composition. Thinning the interfacial Si oxide layer to approximately one monolayer and depositing a metal layer on the HfO 2 surface suppressed these phenomena. The O 1s photoelectron spectra revealed marked differences between the metal- and nonmetal-deposited HfO 2 /SiO 2 /Si structures; HfO 2 and SiO 2 components in the O 1s photoelectron spectra for the metal-deposited structures were observed at reasonably separated binding energies, but those for the nonmetal-deposited structures were not separated clearly. From this behavior concerning the effects of interfacial SiO 2 and surface metal layers, we concluded that the Hf 4f, Hf 3d, and O 1s spectra measured from the HfO 2 /SiO 2 /Si structures did not reflect actual chemical bonding states. We consider that potential variations in the HfO 2 film owing to charge trapping strongly affect the measured photoelectron spectra. On the basis of angle-resolved XPS measurements, we propose that positive charges are trapped at the HfO 2 surface and negative charges are trapped inside the HfO 2 layer. (author)

Development of human factors design review guidelines(II)

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung Woon; Oh, In Suk; Suh, Sang Moon; Lee, Hyun Chul [Korea Atomic Energy Research Institute, Taejon (Korea)

1998-06-01

The objective of this study is to develop human factors engineering program review guidelines and alarm system review guidelines in order to resolve the two major technical issues: 25. Human Factors Engineering Program Review Model and 26. Review Criteria for Human Factors Aspects of Advanced Controls and Instrumentation, which are related to the development of human factors safety regulation guides being performed by KINS. For the development of human factors program review guidelines, we made a Korean version of NUREG-0711 and added our comments by considering Korean regulatory situation and reviewing the reference documents of NUREG-0711. We also computerized the Korean version of NUREG-0711, additional comments, and selected portion of the reference documents for the developer of safety regulation guides in KINS to see the contents comparatively at a glance and use them easily. For the development of alarm system review guidelines, we made a Korean version of NUREG/CR-6105, which was published by NRC in 1994 as a guideline document for the human factors review of alarm systems. Then we will update the guidelines by reviewing the literature related to alarm design published after 1994. (author). 11 refs., 2 figs., 2 tabs.

Oxidation Study of an Ultra High Temperature Ceramic Coatings Based on HfSiCN

Science.gov (United States)

Sacksteder, Dagny; Waters, Deborah L.; Zhu, Dongming

2018-01-01

High temperature fiber-reinforced ceramic matrix composites (CMCs) are important for aerospace applications because of their low density, high strength, and significantly higher-temperature capabilities compared to conventional metallic systems. The use of the SiCf/SiC and Cf/SiC CMCs allows the design of lighter-weight, more fuel efficient aircraft engines and also more advanced spacecraft airframe thermal protection systems. However, CMCs have to be protected with advanced environmental barrier coatings when they are incorporated into components for the harsh environments such as in aircraft engine or spacecraft applications. In this study, high temperature oxidation kinetics of an advanced HfSiCN coating on Cf/SiC CMC substrates were investigated at 1300 C, 1400 C, and 1500 C by using thermogravimetric analysis (TGA). The coating oxidation reaction parabolic rate constant and activation energy were estimated from the experimental results. The oxidation reaction studies showed that the coatings formed the most stable, predominant HfSiO4-HfO2 scales at 1400 C. A peroxidation test at 1400 C then followed by subsequent oxidation tests at various temperatures also showed more adherent scales and slower scale growth because of reduced the initial transient oxidation stage and increased HfSiO4-HfO2 content in the scales formed on the HfSiCN coatings.

Plasma urocortin in human systolic heart failure.

Science.gov (United States)

Ng, Leong L; Loke, Ian W; O'Brien, Russell J; Squire, Iain B; Davies, Joan E

2004-04-01

Urocortin (UCN), a member of the corticotrophin-releasing factor family, is expressed in heart, brain and gut. UCN has potent cardiostimulatory, cardioprotective, vasodilator and diuretic/natriuretic effects, and cardiac UCN expression is increased in heart failure (HF). In the present study, we investigated plasma levels of UCN in 119 patients with HF and 212 age- and gender-matched controls to clarify its relationship with gender and disease severity. UCN was elevated in HF [normal males, 19.5 (3.9-68.8) pmol/l and HF males, 50.2 (6.9-108.2) pmol/l, P fall in UCN levels with increasing NYHA class was reinforced by a significant correlation between UCN and ejection fraction ( r(s) = 0.45, P < 0.0005) in HF patients. Although receiver operating characteristic (ROC) curves for diagnosis of all HF cases yielded an area under the curve (AUC) of 0.76, ROC AUCs for patients with early HF (NYHA class I and II) were better (0.91). ROC AUCs for logistic models incorporating N-terminal probrain natriuretic peptide (N-BNP) and UCN were better than either peptide alone. In conclusion, plasma UCN is elevated in HF, especially in its early stages. Its decline with increasing HF severity may expedite disease progression due to diminished cardioprotective/anti-inflammatory effects. UCN measurement may also complement N-BNP in the diagnosis of early HF.

Thermal expansion studies on HfO2-Gd2O3 system

International Nuclear Information System (INIS)

Panneerselvam, G.; Antony, M.P.; Nagarajan, K.

2014-01-01

A series of solid solutions containing GdO 1.5 in HfO 2 , (Hf 1-y Gd y ) O 2 (y = 0.15, 0.2, 0.3, 0.41 and 0.505) were prepared by solid state method. Structural characterization and computation of lattice parameter was carried out using room temperature X-ray diffraction measurements

The effects of sacubitril/valsartan on coronary outcomes in PARADIGM-HF.

Science.gov (United States)

Mogensen, Ulrik M; Køber, Lars; Kristensen, Søren L; Jhund, Pardeep S; Gong, Jianjian; Lefkowitz, Martin P; Rizkala, Adel R; Rouleau, Jean L; Shi, Victor C; Swedberg, Karl; Zile, Michael R; Solomon, Scott D; Packer, Milton; McMurray, John J V

2017-06-01

Angiotensin converting enzyme inhibitors (ACE-I), are beneficial both in heart failure with reduced ejection fraction (HF-REF) and after myocardial infarction (MI). We examined the effects of the angiotensin-receptor neprilysin inhibitor sacubitril/valsartan, compared with the ACE-I enalapril, on coronary outcomes in PARADIGM-HF. We examined the effect of sacubitril/valsartan compared with enalapril on the following outcomes: i) the primary composite endpoint of cardiovascular (CV) death or HF hospitalization, ii) a pre-defined broader composite including, in addition, MI, stroke, and resuscitated sudden death, and iii) a post hoc coronary composite of CV-death, non-fatal MI, angina hospitalization or coronary revascularization. At baseline, of 8399 patients, 3634 (43.3%) had a prior MI and 4796 (57.1%) had a history of any coronary artery disease. Among all patients, compared with enalapril, sacubitril/valsartan reduced the risk of the primary outcome (HR 0.80 [0.73-0.87], Psacubitril/valsartan group, compared with the enalapril group, only CV death was reduced significantly. Compared with enalapril, sacubitril/valsartan reduced the risk of both the primary endpoint and a coronary composite outcome in PARADIGM-HF. Additional studies on the effect of sacubitril/valsartan on atherothrombotic outcomes in high-risk patients are merited. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparation and characterization of Ce-doped HfO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Gálvez-Barboza, S. [Centro de Investigación en Química Aplicada, Departamento de Materiales Avanzados, Blvd. Enrique Reyna Hermosillo #140, C.P. 25294 Saltillo, Coahuila (Mexico); Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Industria Metalúrgica # 1062 Parque Industrial, C.P. 25900 Ramos Arizpe, Coahuila (Mexico); González, L.A. [Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Industria Metalúrgica # 1062 Parque Industrial, C.P. 25900 Ramos Arizpe, Coahuila (Mexico); Puente-Urbina, B.A.; Saucedo-Salazar, E.M. [Centro de Investigación en Química Aplicada, Departamento de Materiales Avanzados, Blvd. Enrique Reyna Hermosillo #140, C.P. 25294 Saltillo, Coahuila (Mexico); García-Cerda, L.A., E-mail: luis.garcia@ciqa.edu.mx [Centro de Investigación en Química Aplicada, Departamento de Materiales Avanzados, Blvd. Enrique Reyna Hermosillo #140, C.P. 25294 Saltillo, Coahuila (Mexico)

2015-09-15

Highlights: • Ce-doped HfO{sub 2} nanoparticles were prepared by a modified solgel method. • Ce-doped HfO{sub 2} nanoparticles have a semispherical shape with sizes between 6 and 11.5 nm. • The samples doped with 10% in weight of Ce directly crystallized in a cubic structure. • A quick, straightforward and effective route for the preparation of Ce-doped nanoparticles. - Abstract: A modified solgel method to synthesize Ce-doped HfO{sub 2} nanoparticles was carried out using a precursor material prepared with cerium nitrate, hafnium chloride, citric acid and ethylene glycol. The obtained precursor material was calcined at 500 and 700 °C for 2 h in air. The influence of the concentration of Ce and the calcination temperature was studied to observe the structural and morphological changes of the obtained materials. For the characterization, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman scattering (RS) were employed. The XRD patterns shown that the Ce-doped HfO{sub 2} undergoes a structural transformation from monoclinic to cubic phase, which is significantly dependent on the Ce content and calcination temperature. TEM images have also confirmed the existence of semispherical nanoparticles with sizes between 6 and 11.5 nm.

Nuclear Regulatory Commission Human Factors Program Plan. Revision 2

International Nuclear Information System (INIS)

1986-04-01

This document is the Second Annual Revision to the NRC Human Factors Program Plan. The first edition was published in August 1983. Revision 1 was published in July of 1984. Purpose of the NRC Human Factors Program is to ensure that proper consideration is given to human factors in the design and operation of nuclear power plants. This document describes the plans of the Office of Nuclear Reactor Regulation to address high priority human factors concerns of importance to reactor safety in FY 1986 and FY 1987. Revision 2 of the plan incorporates recent Commission decisions and policies bearing on the human factors aspects of reactor safety regulation. With a few exceptions, the principal changes from prior editions reflect a shift from developing new requirements to staff evaluation of industry progress in resolving human factors issues. The plan addresses seven major program elements: (1) Training, (2) Licensing Examinations, (3) Procedures, (4) Man-Machine Interface, (5) Staffing and Qualifications, (6) Management and Organization, and (7) Human Performance

Statistical gamma transitions in {sup 174}Hf

Energy Technology Data Exchange (ETDEWEB)

Farris, L P; Cizewski, J A; Brinkman, M J; Henry, R G; Lee, C S [Rutgers--the State Univ., New Brunswick, NJ (United States); Khoo, T L; Janssens, R V.F.; Moore, E F; Carpenter, M P; Ahmad, I; Lauritsen, T [Argonne National Lab., IL (United States); Kolata, J J; Beard, K B; Ye, B; Garg, U [Notre Dame Univ., IN (United States); Kaplan, M S; Saladin, J X; Winchell, D [Pittsburgh Univ., PA (United States)

1992-08-01

The statistical spectrum extracted from the {sup 172}Yb({alpha},2n){sup 174}Hf reaction was fit with Monte Carlo simulations using a modified GDR E1 strength function and several formulations of the level density. (author). 15 refs., 1 tab., 3 figs.

Human Factors Simulation in Construction Management Education

Science.gov (United States)

Jaeger, M.; Adair, D.

2010-01-01

Successful construction management depends primarily on the representatives of the involved construction project parties. In addition to effective application of construction management tools and concepts, human factors impact significantly on the processes of any construction management endeavour. How can human factors in construction management…

Human Factor on Gravelines Nuclear Power Plants

International Nuclear Information System (INIS)

Duboc, Gerard

1998-01-01

In a first part, the documents describes the commitments by EDF nuclear power plan operations to demands made by the Safety Authority regarding actions in the field of human factors (concerns expressed by the Authority, in-depth analysis, positions on different points raised by the Authority). In a second part, it presents the various actions undertaken in the Gravelines nuclear power station regarding human factors: creation of an 'operator club' (mission and objectives, methods and means, first meetings, tracking file), development of risk analysis strategy, setting up of a human factor engineering mission and example of action in case of a significant event

Overview of EPRI's human factors research program

International Nuclear Information System (INIS)

O'Brien, J.F.; Parris, H.L.

1981-01-01

The human factors engineering program in the Nuclear Power Division, EPRI is dedicated to the resolution of man-machine interface problems specific to the nuclear power industry. Particularly emphasis is placed on the capabilities and limitations of the people who operate and maintain the system, the tasks they must perform, and what they need to accomplish those tasks. Six human factors R and D projects are being conducted at the present time. In addition, technical consultation is being furnished to a study area, operator aids, being funded by another program area outside the human factors program area. All of these activities are summarized

Structure and properties of a model conductive filament/host oxide interface in HfO2-based ReRAM

Science.gov (United States)

Padilha, A. C. M.; McKenna, K. P.

2018-04-01

Resistive random-access memory (ReRAM) is a promising class of nonvolatile memory capable of storing information via its resistance state. In the case of hafnium oxide-based devices, experimental evidence shows that a conductive oxygen-deficient filament is formed and broken inside of the device by oxygen migration, leading to switching of its resistance state. However, little is known about the nature of this conductive phase, its interface with the host oxide, or the associated interdiffusion of oxygen, presenting a challenge to understanding the switching mechanism and device properties. To address these problems, we present atomic-scale first-principles simulations of a prototypical conductive phase (HfO), the electronic properties of its interface with HfO2, as well as stability with respect to oxygen diffusion across the interface. We show that the conduction-band offset between HfO and HfO2 is 1.3 eV, smaller than typical electrode-HfO2 band offsets, suggesting that positive charging and band bending should occur at the conductive filament-HfO2 interface. We also show that transfer of oxygen across the interface, from HfO2 into HfO, costs around 1.2 eV per atom and leads to a gradual opening of the HfO band gap, and hence disruption of the electrical conductivity. These results provide invaluable insights into understanding the switching mechanism for HfO2-based ReRAM.

Customized binary and multi-level HfO2-x-based memristors tuned by oxidation conditions.

Science.gov (United States)

He, Weifan; Sun, Huajun; Zhou, Yaxiong; Lu, Ke; Xue, Kanhao; Miao, Xiangshui

2017-08-30

The memristor is a promising candidate for the next generation non-volatile memory, especially based on HfO 2-x , given its compatibility with advanced CMOS technologies. Although various resistive transitions were reported independently, customized binary and multi-level memristors in unified HfO 2-x material have not been studied. Here we report Pt/HfO 2-x /Ti memristors with double memristive modes, forming-free and low operation voltage, which were tuned by oxidation conditions of HfO 2-x films. As O/Hf ratios of HfO 2-x films increase, the forming voltages, SET voltages, and R off /R on windows increase regularly while their resistive transitions undergo from gradually to sharply in I/V sweep. Two memristors with typical resistive transitions were studied to customize binary and multi-level memristive modes, respectively. For binary mode, high-speed switching with 10 3 pulses (10 ns) and retention test at 85 °C (>10 4 s) were achieved. For multi-level mode, the 12-levels stable resistance states were confirmed by ongoing multi-window switching (ranging from 10 ns to 1 μs and completing 10 cycles of each pulse). Our customized binary and multi-level HfO 2-x -based memristors show high-speed switching, multi-level storage and excellent stability, which can be separately applied to logic computing and neuromorphic computing, further suitable for in-memory computing chip when deposition atmosphere may be fine-tuned.