Discrimination of Thermal versus Mechanical Effects of Shock on Rock Magnetic Properties of Spherically Shocked up to 10-160 GPa Basalt and Diabase

NASA Astrophysics Data System (ADS)

Bezaeva, N. S.; Swanson-Hysell, N.; Tikoo, S.; Badyukov, D. D.; Kars, M. A. C.; Egli, R.; Chareev, D. A.; Fairchild, L. M.

2016-12-01

Understanding how shock waves generated during hypervelocity impacts affect rock magnetic properties is key for interpreting the paleomagnetic records of lunar rocks, meteorites, and cratered planetary surfaces. Laboratory simulations of impacts show that ultra-high shocks may induce substantial post-shock heating of the target material. At high pressures (>10 GPa), shock heating occurs in tandem with mechanical effects, such as grain fracturing and creation of crystallographic defects and dislocations within magnetic grains. This makes it difficult to conclude whether shock-induced changes in the rock magnetic properties of target materials are primarily associated with mechanical or thermal effects. Here we present novel experimental methods to discriminate between mechanical and thermal effects of shock on magnetic properties and illustrate it with two examples of spherically shocked terrestrial basalt and diabase [1], which were shocked to pressures of 10 to >160 GPa, and investigate possible explanations for the observed shock-induced magnetic hardening (i.e., increase in remanent coercivity Bcr). The methods consist of i) conducting extra heating experiments at temperatures resembling those experienced during high-pressure shock events on untreated equivalents of shocked rocks (with further comparison of Bcr of shocked and heated samples) and ii) quantitative comparison of high-resolution first-order reversal curve (FORC) diagrams (field step: 0.5-0.7 mT) for shocked, heated and untreated specimens. Using this approach, we demonstrated that the shock-induced coercivity hardening in our samples is predominantly due to solid-state, mechanical effects of shock rather than alteration associated with shock heating. Indeed, heating-induced changes in Bcr in the post-shock temperature range were minor. Visual inspection of FORC contours (in addition to detailed analyses) reveals a stretching of the FORC distribution of shocked sample towards higher coercivities, consistent with shock-induced hardening. However, shock does not alter the intrinsic shape of coercivity and the shape of FORC contours (apart from field scaling) while heating does, which is seen as a significant alteration of FORC contours. Reference: [1] Swanson-Hysell N. L. et al. 2014. G3 15:2039-2047.

Simultaneous magnetic investigations of Cu precipitation and recovery in thermally aged Fe-Cu alloy by first-order-reversal-curves

NASA Astrophysics Data System (ADS)

Kobayashi, Satoru; Kawagoe, Riko; Murakami, Hiroaki

2018-05-01

We have measured first-order reversal curves (FORCs) for Fe-1wt%Cu alloy thermally aged at 753 K up to 20000 min. While hardness exhibits a maximum at around 1000 min, reflecting the formation and growth of Cu precipitates, major-loop coercivity monotonically decreases and becomes almost constant above 100 min.; an increase of coercivity associated with Cu precipitation is masked by a large decrease due to recovery. On the other hand, FORC diagrams exhibit two distribution peaks at low and high switching fields after aging. While the former shifts towards a lower switching field after aging, reflecting recovery, the latter shows up after aging up to ˜1000 min, possibly due to the formation of Cu precipitates. These observations demonstrate that FORCs are useful to separately evaluate competing microstructural changes in thermally aged Fe-Cu alloy where recovery and Cu precipitation take place simultaneously.

Roughness-Induced Magnetic Domain in Fe Thin Films on Land-and-Groove Structures Studied by Spin-Polarized Secondary Electron Microscopy

NASA Astrophysics Data System (ADS)

Ueda, Shigenori; Iwasaki, Yoh; Ushioda, Sukekatsu

2003-10-01

The magnetic domain structures of Fe thin films on two-dimensionally arranged land-and-groove structures have been studied by spin-polarized secondary electron microscopy (SP-SEM) under an applied dc field. The coercive force on the land area was found to be higher than that on the groove area under magnetization reversal. The surface roughness measured by atomic force microscopy (AFM) was greater on the land area than on the groove area. The roughness-induced high-coercivity on the land prevented the reversed magnetic domain on the groove from spreading over the land in the initial magnetization reversal. This result indicates that surface roughness is an important factor in domain size control of thin magnetic films.

Nonlinear geometric scaling of coercivity in a three-dimensional nanoscale analog of spin ice

NASA Astrophysics Data System (ADS)

Shishkin, I. S.; Mistonov, A. A.; Dubitskiy, I. S.; Grigoryeva, N. A.; Menzel, D.; Grigoriev, S. V.

2016-08-01

Magnetization hysteresis loops of a three-dimensional nanoscale analog of spin ice based on the nickel inverse opal-like structure (IOLS) have been studied at room temperature. The samples are produced by filling nickel into the voids of artificial opal-like films. The spin ice behavior is induced by tetrahedral elements within the IOLS, which have the same arrangement of magnetic moments as a spin ice. The thickness of the films vary from a two-dimensional, i.e., single-layered, antidot array to a three-dimensional, i.e., multilayered, structure. The coercive force, the saturation, and the irreversibility field have been measured in dependence of the thickness of the IOLS for in-plane and out-of-plane applied fields. The irreversibility and saturation fields change abruptly from the antidot array to the three-dimensional IOLS and remain constant upon further increase of the number of layers n . The coercive force Hc seems to increase logarithmically with increasing n as Hc=Hc 0+α ln(n +1 ) . The logarithmic law implies the avalanchelike remagnetization of anisotropic structural elements connecting tetrahedral and cubic nodes in the IOLS. We conclude that the "ice rule" is the base of mechanism regulating this process.

Magnetic Force Microscopy Investigation of Magnetic Domains in Nd2Fe14B

NASA Astrophysics Data System (ADS)

Talari, Mahesh Kumar; Markandeyulu, G.; Rao, K. Prasad

2010-07-01

Remenance and coercivity in Nd2Fe14B materials are strongly dependent on the microstructural aspects like phases morphology and grain size. The coercivity (Hc) of a magnetic material varies inversely with the grain size (D) and there is a critical size below which Hc∝D6. Domain wall pinning by grain boundaries and foreign phases is the important mechanism in explaining the improvement in coercivity and remenance. Nd2Fe14B intermetallic compound with stochiometric composition was prepared from pure elements (Nd -99.5%, Fe—99.95%, B -99.99%) by arc melting in argon atmosphere. Magnetic Force Microscope (MFM) gives high-resolution magnetic domain structural information of ferromagnetic samples. DI-3100 Scanning Probe Microscope with MESP probes was used For MFM characterization of the samples. Magnetic domains observed in cast ingots were very long (up to 40 μm were observed) and approximately 1-5 μm wide due to high anisotropy of the compounds. Magnetic domains have displayed different image contrast and morphologies at different locations of the samples. The domain morphologies and image contrast obtained in this analysis were explained in this paper.

Gender differences in patterns of experienced sexual coercion and associated vulnerability factors among young people in the Netherlands.

PubMed

Kuyper, Lisette; de Wit, John; Smolenski, Derek; Adam, Philippe; Woertman, Liesbeth; van Berlo, Willy

2013-11-01

The development of effective policies and programs to prevent sexual coercion among young people requires thorough understanding of the diversity of coercive sexual experiences, patterns in such types of experiences, and similarities and differences between subgroups, especially by gender, in patterns of coercive sexual experiences and associations with potential vulnerability factors. The present online self-report study assessed a wide range of coercive sexual experiences and potential vulnerability factors among a sociodemographically diverse sample of 1,319 young people (16-25 years old) in The Netherlands. Findings confirm that sexual coercion comprises a diversity of experiences, with rates differing substantially across types of coercion. Latent class analysis revealed distinct patterns of coercive sexual experiences for young women and young men. Among young men, three patterns of experiences were found: no coercive sexual experiences, experience with verbal pressure, and experience with verbal pressure as well as coercion related to alcohol intoxication. Among young women, four patterns of coercive experiences were identified. In addition to the three patterns observed among young men, a fourth pattern encompassed experiences with verbal pressure as well as the use of force or violence. Higher numbers of sexual partners, lower levels of sexual refusal skills, and higher levels of token resistance were consistently associated with increased vulnerability. Findings illustrate the importance of communication skills and suggest that sexual communication training should be an integral part of sexuality education.

Subjective experience of coercion in psychiatric care: a study comparing the attitudes of patients and healthy volunteers towards coercive methods and their justification.

PubMed

Mielau, J; Altunbay, J; Gallinat, J; Heinz, A; Bermpohl, F; Lehmann, A; Montag, C

2016-06-01

Under certain conditions, coercive interventions in psychotic patients can help to regain insight and alleviate symptoms, but can also traumatize subjects. This study explored attitudes towards psychiatric coercive interventions in healthy individuals and persons suffering from schizophrenia, schizoaffective or bipolar disorder. The impact of personal history of coercive treatment on preferences concerning clinical management of patients unable to consent was investigated. Six case vignettes depicting scenarios of ethical dilemmas and demanding decisions in favour of or against coercive interventions were presented to 60 healthy volunteers and 90 patients. Structured interviews focusing on experienced coercion were performed in conjunction with the Coercion Experience Scale and the Admission Experience Survey. Symptom severity, psychosocial functioning and insight into illness were assessed as influencing variables. Student's t tests compared patients' and controls' judgments, followed by regression analyses to define the predictive value of symptoms and measures of coercion on judgments regarding the total patient sample and patients with experience of fixation. Patients and non-psychiatric controls showed no significant difference in their attitudes towards involuntary admission and forced medication. Conversely, patients more than controls significantly disapproved of mechanical restraint. Subjective experience of coercive interventions played an important role for the justification of treatment against an individual's "natural will". Factors influencing judgments on coercion were overall functioning and personal experience of treatment effectiveness and fairness. Qualitative and quantitative aspects of perceived coercion, in addition to insight into illness, predicted judgments of previously fixated patients. Results underline the importance of the quality of practical implementation and care, if coercive interventions cannot be avoided.

Systematic impact of institutional pressures on safety climate in the construction industry.

PubMed

He, Qinghua; Dong, Shuang; Rose, Timothy; Li, Heng; Yin, Qin; Cao, Dongping

2016-08-01

This paper explores how three types of institutional pressure (i.e., coercive, mimetic and normative pressures) systematically impact on the safety climate of construction projects. These impacts are empirically tested by survey data collected from 186 questionnaires of construction companies operating in Shanghai, China. The results, obtained by partial least squares analysis, show that organizational management commitment to safety and employee involvement is positively related to all three institutional pressures, while the perception of responsibility for safety and health is significantly influenced by coercive and mimetic pressure. However, coercive and normative pressures have no significant effect on the applicability of safety rules and work practices, revealing the importance of external organizational pressures in improving project safety climate from a systematic view. The findings also provide insights into the use of institutional forces to facilitate the improvement of safety climate in the construction industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spin reorientation transition and hard magnetic properties of MnBi intermetallic compound

NASA Astrophysics Data System (ADS)

Suzuki, K.; Wu, X.; Ly, V.; Shoji, T.; Kato, A.; Manabe, A.

2012-04-01

The effects of mechanical grinding (MG) on the crystallite size, the spin reorientation transition temperature (TSR) and the hard magnetic properties in melt-spun low temperature phase (LTP) MnBi have been investigated in order to understand the origin of magnetic hardening induced by MG. The room-temperature coercive field (μ0Hcj) is enhanced dramatically from 0.08 T before MG to 1.5 T after MG for 43.2 ks while TSR is concurrently suppressed from 110 to 38 K. The coercive force exhibits positive temperature dependence approximately 50-60 K above TSR and the lowered TSR after MG could result in magnetic hardening at room temperature. The room-temperature coercive force of LTP-MnBi is highly dependent on the crystallite size (D) and is found to be described phenomenologically by the following relationship: μ0Hcj = μ0Ha(δ/D)n, where μ0Ha is ˜ 4 T, the Bloch wall width δ is 7 nm, and the exponent n is approximately 0.7. Our results suggest that the grain refinement is the primary origin of the hardening effect induced by MG with a possible minor hardening effect due to the suppression of the spin reorientation transition temperature.

Irreversible evolution of angular-dependent coercivity in Fe80Ni20 nanowire arrays: Detection of a single vortex state

NASA Astrophysics Data System (ADS)

Alikhani, M.; Ramazani, A.; Almasi Kashi, M.; Samanifar, S.; Montazer, A. H.

2016-09-01

The irreversible evolution of magnetic coercivity in arrays of 75 nm diameter Fe80Ni20 nanowires (NWs) has been explored by means of first-order reversal curve (FORC) analysis as a function of the angle between the magnetic field and the NW axis (0°≤θ≤90°). The Fe80Ni20 NWs with lengths up to 60 μm were fabricated using a pulsed electrodeposition method into hard-anodic aluminum oxide templates with an interpore distance of 275 nm. Investigating the interwire and intrawire magnetostatic interactions, the angular FORC (AFORC) diagrams indicated enhanced intrawire interactions with increasing length and θ (<90°), induced by a magnetization reversal through vortex domain wall (VDW) propagation. Intriguingly, in addition to the VDW mode, a single vortex state with broad irreversible switching of nucleation and annihilation fields was detected at θ=83° for 60 μm long NWs. At θ=90°, the NWs reversed magnetization through transverse domain wall, involving a reversible component by a fraction of 95%. Furthermore, the transition angle between the reversal modes was found to decrease with increasing aspect ratio from 200 to 800. The irreversible angular-dependent coercivity (HcIrrev(θ)) of Fe80Ni20 NWs was extracted from the AFORC measurements and compared with the major angular dependence of coercivity (HcMajor(θ)) obtained from the conventional hysteresis loop measurements. While HcMajor(θ) showed a non-monotonic behavior, HcIrrev(θ) constantly increased with increasing θ (<90°). On the other hand, using analytical models, a 93% agreement was obtained between the theoretical angular-dependent nucleation field and experimental HcIrrev(θ) for irreversible switching of VDW when 0°≤θ≤86°.

Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets

NASA Astrophysics Data System (ADS)

Matsuura, Yutaka; Nakamura, Tetsuya; Sumitani, Kazushi; Kajiwara, Kentaro; Tamura, Ryuji; Osamura, Kozo

2018-01-01

Experimental results of the alignment dependence of the coercivity in Nd-Fe-B sintered magnets showed that the angle of magnetization reversal for anisotropically aligned magnets was bigger than that obtained from the theoretical results calculated using the postulation that every grain independently reverses its magnetization direction following the 1/cos θ law. The angles of reversed magnetization (θ1) for Nd13.48Co0.55B5.76Febal. with alignment α=0.95 and for Nd12.75Dy0.84B5.81Co0.55Febal. with α=0.96 were 30° and 36°, respectively, which were very similar to that of an ideal magnet with a Gaussian distribution (σ=31° and 44°, respectively) of the grain alignment. In this model, we postulated that every grain independently reversed according to the 1/cos θ law. The calculation results for the angular dependence of the coercivity using the values θ1=ω1(0°)=30°, σ=31° and θ1=ω1(0°)=36°, σ=44° could qualitatively and convincingly explain the observed angular dependence of the coercivity of Nd14.2B6.2Co1.0Febal. and Nd14.2Dy0.3B6.2Co1.0Febal.. It is speculated that the magnetic domain wall is pinned at grains tilted away from the easy magnetization direction, and when the magnetic domain wall de-pins from the tilted grains, the magnetic domain wall jumps through several grains. We suggest that the coercive force of the aligned magnet behaves like a low-aligned magnet owing to the magnetization reversal of the crust of the grains induced by the pinning and subsequent jumping of the magnetic domain wall.

Searching for solutions to alcohol and other drug abuse during pregnancy: ethics, values, and constitutional principles.

PubMed

Andrews, A B; Patterson, E G

1995-01-01

Recent efforts to develop legal mechanisms to detect prenatal substance abuse and force pregnant women into drug-free conditions have precipitated ethical struggles for social workers. This article reviews relevant social work values and ethical issues, particularly the need to balance obligations to promote client self-determination, privacy, and access to chosen services with professional values that support coercive intervention to aid vulnerable people and to protect life. The constitutional principles that most affect coercive interventions--due process and equal protection--are reviewed. Recommendations are offered to guide ethical and legal social work for case interventions and policy development.

The Legality of Nuclear Weapons Employment under the International Humanitarian Law of Coercion Control.

DTIC Science & Technology

1987-01-01

fm$0 TELMT OF NUICLEMR IdERPONiS EMPLOYMENT UNDERTH 1/ I INTERNRTIOSEL NUIfI.. (U) AIR FORCE INST OF TECH I NRIONT-PATTERSON AFI ON R R PRICE 1967...Coercion Control c. Rank: Major d. Service: United States Air Force e. Date: 1987 I . Number of pages: 106 g. Degree awarded: Master ot Laws (LL.M.) in...33 A. Sources of International Humanitarian Law ............ 33 B. Use of Coercive Force Under International Law ..... 34 C. Basis Principles

"Treat me with respect". A systematic review and thematic analysis of psychiatric patients' reported perceptions of the situations associated with the process of coercion.

PubMed

Tingleff, E B; Bradley, S K; Gildberg, F A; Munksgaard, G; Hounsgaard, L

2017-11-01

WHAT IS KNOWN ON THE SUBJECT?: Psychiatric patients have generally negative experiences of being exposed to coercive measures. Existing research has generally not investigated coercion as a process; that is, it does not address issues that arise before, during and after exposure to coercion. A part of existing research within the area does not clarify and define the type of coercive measure(s) investigated. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Patients place great significance on the link between the positive and negative perceived impact of a coercive situation and the professionals' ability and willingness to interact and communicate respectfully. Psychiatric patients associate the use of seclusion, physical restraint/holding, mechanical restraint and forced medication with strong negative perceptions and wish to be treated with respect by professionals, rather than being subjected to the professionals' control. What patients perceive as moderating factors in regard to the use of coercive measures is currently under-researched. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Increased sensitivity to the patient's views of the situation at each point in the coercive process would help professionals to respond to the patients' individual needs. Professionals need to articulate concern and empathy towards patients and to improve communication skills before, during and after a coercive incident. Greater emphasis should be placed on de-escalation and the use of non-coercive strategies or coping skills before the initiation of coercive measures. Introduction There is a lack of research into psychiatric patients' perceptions of coercion that discriminates between different types of coercive measures, while also investigating patients' perceptions of undergoing coercion as a process. This knowledge is required to improve our understanding and provide a foundation for improving clinical practice. Aims To review existing research literature in order to investigate adult psychiatric patients' reported perceptions of situations before, during and after specific and defined types of coercive measures, and to investigate what patients perceive as moderating factors, in regard to the use of these coercive measures. Method A systematic review and thematic analysis of 26 peer-reviewed studies was undertaken. Results The analysis identified six themes and additional subthemes, where "interactions with professionals" and "communication" were predominant themes across the timeline of coercion. Altogether, themes were associated with either "positive or negative patient-perceived impact." Implications for practice Increased sensitivity to patients' views of the situation at each point in the process is desirable in order to respond to the patients' individual needs. Professionals also need to articulate concern and empathy towards the patient and to improve communication skills before, during and after a coercive incident. Use of de-escalation and noncoercive strategies is required. Relevance statement Coercion within psychiatric/mental health care remains controversial, and repeated international calls have recommended a reduction of their use. This review indicates that greater attention to how patients perceive the use of coercive measures (before, during, and after incidents) needs to be considered in order to improve the evidence-based and clinical practice. © 2017 John Wiley & Sons Ltd.

Coercive Diplomacy American-Style.

DTIC Science & Technology

1997-02-21

invasion force was deployed and presumably beyond the control of the distinguished negotiators ("Team Carter") on the ground. The Haitian strongman , Raoul...should have little difficulty drumming up a large amount of luke -warm support for its efforts against the communist behemoth, with the unfortunate

Insights into magmatic processes and hydrothermal alteration of in situ superfast spreading ocean crust at ODP/IODP site 1256 from a cluster analysis of rock magnetic properties

NASA Astrophysics Data System (ADS)

Dekkers, Mark J.; Heslop, David; Herrero-Bervera, Emilio; Acton, Gary; Krasa, David

2014-08-01

We analyze magnetic properties from Ocean Drilling Program (ODP)/Integrated ODP (IODP) Hole 1256D (6°44.1' N, 91°56.1' W) on the Cocos Plate in ˜15.2 Ma oceanic crust generated by superfast seafloor spreading, the only drill hole that has sampled all three oceanic crust layers in a tectonically undisturbed setting. Fuzzy c-means cluster analysis and nonlinear mapping are utilized to study down-hole trends in the ratio of the saturation remanent magnetization and the saturation magnetization, the coercive force, the ratio of the remanent coercive force and coercive force, the low-field magnetic susceptibility, and the Curie temperature, to evaluate the effects of magmatic and hydrothermal processes on magnetic properties. A statistically robust five cluster solution separates the data predominantly into three clusters that express increasing hydrothermal alteration of the lavas, which differ from two distinct clusters mainly representing the dikes and gabbros. Extensive alteration can obliterate magnetic property differences between lavas, dikes, and gabbros. The imprint of thermochemical alteration on the iron-titanium oxides is only partially related to the porosity of the rocks. Thus, the analysis complements interpretation based on electrofacies analysis. All clusters display rock magnetic characteristics compatible with an ability to retain a stable natural remanent magnetization suggesting that the entire sampled sequence of ocean crust can contribute to marine magnetic anomalies. Paleointensity determination is difficult because of the propensity of oxyexsolution during laboratory heating and/or the presence of intergrowths. The upper part of the extrusive sequence, the granoblastic dikes, and moderately altered gabbros may contain a comparatively uncontaminated thermoremanent magnetization.

Magnetic Behavior of Ni-Fe Core-Shell and Alloy Nanowires

NASA Astrophysics Data System (ADS)

Tripathy, Jagnyaseni; Vargas, Jose; Spinu, Leonard; Wiley, John

2013-03-01

Template assisted synthesis was used to fabricate a series of Ni-Fe core-shell and alloy nanowires. By controlling reaction conditions as well as pore structure, both systems could be targeted and magnetic properties followed as a function of architectures. In the core-shell structure coercivity increases with decrease in shell thickness while for the alloys, coercivity squareness improve with increase pore diameter. Details on the systematic studies of these materials will be presented in terms of hysteretic measurements, including first order reversal curves (FORC), and FMR data. Magnetic variation as a function of structure and nanowire aspect ratios will be presented and the origins of these behaviors discussed. Advanced Material Research Institute

Sexually coercive behavior in male youth: population survey of general and specific risk factors.

PubMed

Kjellgren, Cecilia; Priebe, Gisela; Svedin, Carl Göran; Långström, Niklas

2010-10-01

Little is known about risk/protective factors for sexually coercive behavior in general population youth. We used a Swedish school-based population survey of sexual attitudes and experiences (response rate 77%) and investigated literature-based variables across sexually coercive (SEX), non-sexual conduct problem (CP), and normal control (NC) participants to identify general and specific risk/protective factors for sexual coercion. Among 1,933 male youth, 101 (5.2%) reported sexual coercion (ever talked or forced somebody into genital, oral, or anal sex) (SEX), 132 (6.8%) were classified as CP, and the remaining 1,700 (87.9%) as NC. Of 29 tested variables, 25 were more common in both SEX and CP compared to NC youth, including minority ethnicity, separated parents, vocational study program, risk-taking, aggressiveness, depressive symptoms, substance abuse, sexual victimization, extensive sexual experiences, and sexual preoccupation. When compared to CP youth only, SEX youth more often followed academic study programs, used less drugs and were less risk-taking. Further, SEX more frequently than CP youth reported gender stereotypic and pro-rape attitudes, sexual preoccupation, prostitution, and friends using violent porn. Finally, in a multivariate logistic regression, academic study program, pro-rape attitudes, sexual preoccupation, and less risk-taking independently remained more strongly associated with SEX compared to CP offending. In conclusion, several sociodemographic, family, and individual risk/protective factors were common to non-sexual and sexually coercive antisocial behavior in late adolescence. However, pro-rape cognitions, and sexual preoccupation, were sexuality-related, specific risk factors. The findings could inform preventive efforts and the assessment and treatment of sexually coercive male youth.

Coercive Effects-based Operations Targeting Enemy Resolve: No Bang for the Buck

DTIC Science & Technology

2007-05-10

http://www.bartelby.com/65/tr/Trenchar.html (accessed 8 April 2007) 15 Pamela Feltus , The Prophets: Advocates of Strategic Bombing, Available...the Air. Washington D.C.: Office of Air Force History, 1983. Feltus , Pamela. “The Prophets: Advocates of Strategic Bombing”. http

Female youth who sexually coerce: prevalence, risk, and protective factors in two national high school surveys.

PubMed

Kjellgren, Cecilia; Priebe, Gisela; Svedin, Carl Göran; Mossige, Svein; Långström, Niklas

2011-12-01

Sexual coercion is recognized as a serious societal problem. Correlates and risk factors of sexually abusive behavior in females are not well known. Etiological theory and empirical study of female perpetrators of sexual coercion are usually based on small or highly selected samples. Specifically, population-based data are needed to elucidate risk/protective factors. Main outcome measures include a self-report questionnaire containing 65 items tapping socio-demographic and health conditions, social relations, sexual victimization, conduct problems and a set of normative and deviant sexual cognitions, attitudes, and behaviors. We used a 2003-2004 survey of sexual attitudes and experiences among high school students in Norway and Sweden to identify risk factors and correlates to sexually coercive behavior (response rate 80%); 4,363 females participated (Mean = 18.1 years). Thirty-seven women (0.8%) reported sexual coercion (ever talked someone into, used pressure, or forced somebody to have sex). Sexually coercive compared with non-coercive women were similar on socio-demographic variables, but reported less parental care and more parental overprotection, aggression, depressive symptoms, and substance misuse. Also, sexually coercive females reported more sexual lust, sex partners, penetrative sexual victimization, rape myths, use of violent porn, and friends more likely to use porn. When using the Swedish subsample to differentiate risk factors specific for sexual coercion from those for antisocial behavior in general, we found less cannabis use, but more sexual preoccupation, pro-rape attitudes, and friends using violent porn in sexually coercive compared with non-sex conduct problem females. Sexually coercive behavior in high school women was associated with general risk/needs factors for antisocial behavior, but also with specific sexuality-related risk factors. This differential effect has previously been overlooked, agrees with similar findings in men, and should have substantial etiological importance. © 2009 International Society for Sexual Medicine.

Markets versus Monopolies in Education: The Historical Evidence.

ERIC Educational Resources Information Center

Coulson, Andrew

1996-01-01

Historical data are presented to show that teachers and schools are affected by the financial incentives of the systems in which they operate. Economic pressures have forced schools in competitive markets to meet the needs of families, while centralized bureaucratic systems have been coercive and pedagogically stagnant. (Author/SLD)

A Theory of the Origin of the State

ERIC Educational Resources Information Center

Carneiro, Robert L.

1970-01-01

Suggests that states evolve in response to ecological or social circumscription, or resource concentration. When dense populations develop, fighting over land forces loser into political subordination or incorporation. This modification of coercive theories explain lack of state in Amazon basin and origin of Inca, Maya, Hwang Valley states.…

Female Genitalia Concealment Promotes Intimate Male Courtship in a Water Strider

PubMed Central

Han, Chang S.; Jablonski, Piotr G.

2009-01-01

Violent coercive mating initiation is typical for animals with sexual conflict over mating. In these species, the coevolutionary arms-race between female defenses against coercive mating and male counter-adaptations for increased mating success leads to coevolutionary chases of male and female traits that influence the mating. It has been controversial whether one of the sexes can evolve traits that allow them to “win” this arms race. Here, we use morphological analysis (traditional and scanning electron micrographs), laboratory experiments and comparative methods to show how females of a species characterized by typical coercive mating initiation appear to “win” a particular stage of the sexual conflict by evolving morphology to hide their genitalia from direct, forceful access by males. In an apparent response to the female morphological adaptation, males of this species added to their typically violent coercive mounting of the female new post-mounting, pre-copulatory courtship signals produced by tapping the water's surface with the mid-legs. These courtship signals are intimate in the sense that they are aimed at the female, on whom the male is already mounted. Females respond to the signals by exposing their hidden genitalia for copulatory intromission. Our results indicate that the apparent victory of coevolutionary arms race by one sex in terms of morphology may trigger evolution of a behavioral phenotype in the opposite sex. PMID:19516886

The Coercive Efficacy of Air Exclusion Zones: Myth or Reality

DTIC Science & Technology

2012-06-01

use force and such threats lacked credibility. The lack of intervention by the international community in other Arab nations may have reinforced such...those of the author. They do not reflect the official position of the US Government, Department of Defense, the United States Air Force, or Air...security. We do not seek the destruction of Iraq, its culture, or its people. Rather, we seek an Iraq that uses its great resources not to destroy, not to

Serial forced displacement in American cities, 1916-2010.

PubMed

Fullilove, Mindy Thompson; Wallace, Rodrick

2011-06-01

Serial forced displacement has been defined as the repetitive, coercive upheaval of groups. In this essay, we examine the history of serial forced displacement in American cities due to federal, state, and local government policies. We propose that serial forced displacement sets up a dynamic process that includes an increase in interpersonal and structural violence, an inability to react in a timely fashion to patterns of threat or opportunity, and a cycle of fragmentation as a result of the first two. We present the history of the policies as they affected one urban neighborhood, Pittsburgh's Hill District. We conclude by examining ways in which this problematic process might be addressed.

Mapping the phase inhomogeneity across first order spin flop transition

NASA Astrophysics Data System (ADS)

Tripathi, Malvika; Majumder, Supriyo; Choudhary, R. J.; Phase, D. M.

2018-04-01

As a consequence of spin reorientation phase transition (SRPT, TSRPT = 34K) in SmCrO3, the two phases, high temperature uncompensated anti-ferromagnetic Γ4 configuration and low temperature collinear anti-ferromagnetic phase Γ1 coexist in the vicinity of transition. The observed unexpectedly huge coercivity (Hc ˜2T) below SRPT at 25K questions on the behavior of two co-existing phases. In the present study, we have used the FORC diagrams to monitor the distribution of clusters related to different phases and to understand the nature of interaction among the clusters of distinct phases. We observed that the nature of interaction has indeed magnetic effect and the pining across phase boundaries may cause the enhancement of coercivity at 25K.

Quantification of the Barkhausen noise method for the evaluation of time-dependent degradation

NASA Astrophysics Data System (ADS)

Kim, Dong-Won; Kwon, Dongil

2003-02-01

The Barkhausen noise (BN) method has long been applied to measure the bulk magnetic properties of magnetic materials. Recently, this important nondestructive testing (NDT) method has been applied to evaluate microstructure, stress distribution analysis, fatigue, creep and fracture characteristics. Until now the BN method has been used only qualitatively in evaluating the variation of BN with variations in material properties. For this reason, few NDT methods have been applied in industrial plants and laboratories. The present investigation studied the coercive force and BN while varying the microstructure of ultrafine-grained steels and SA508 cl.3 steels. This variation was carried out according to the second heat-treatment condition with rolling of ultrafine-grained steels and the simulated time-dependent degradation of SA 508 cl.3 steels. An attempt was also made to quantify BN from the relationship between the velocity of magnetic domain walls and the retarding force, using the coercive force of the domain wall movement. The microstructure variation was analyzed according to time-dependent degradation. Fracture toughness was evaluated quantitatively by measuring the BN from two intermediary parameters; grain size and distribution of nonmagnetic particles. From these measurements, the variation of microstructure and fracture toughness can be directly evaluated by the BN method as an accurate in situ NDT method.

Crimes Of War And The Force Of Law

ERIC Educational Resources Information Center

Hagan, John; Levi, Ron

2005-01-01

The origin and enforcement of criminal law are central to the sociological study of crime, yet we know relatively little about how the coercive apparatus of criminalization is actualized through prosecutorial and court practices. We use Bourdieu's extension of Weber's analysis of law to develop a perspective on fields of practice, the juridical…

Conduct Disorders: Are Boot Camps Effective?

ERIC Educational Resources Information Center

Jeter, LaVaughn V.

2010-01-01

Youth diagnosed with "conduct disorder" are often placed in programs using forced compliance and coercive control. One type of intervention used to treat conduct disorder is the boot camp. The basic idea is that disruptive behaviors can be corrected by strict behavioral regulation and an emphasis on skills training (Weis & Toolis 2009; Weis,…

Design and material selection for inverter transformer cores

NASA Technical Reports Server (NTRS)

Mclyman, W. T.

1973-01-01

Report is announced which studied magnetic properties of candidate materials for use in spacecraft transformers, static inverters, converters, and transformer-rectifier power supplies. Included are material characteristics for available alloy compositions in tabular form, including: trade names, saturated flux density, dc coercive force, loop squareness, material density, and watts per pound at 3 KHz.

Enhancing the magnetic anisotropy energy by tuning the contact areas of Ag and Ni at the Ag/Ni interface.

PubMed

Chow, Yu-Ting; Jiang, Bin-Han; Chang, Cheng-Hsun-Tony; Tsay, Jyh-Shen

2018-01-17

Modifying the interfacial conditions of magnetic layers by capping with overlayers can efficiently enhance the magnetic functionality of a material. However, the mechanisms responsible for this are closely related to the crystalline structure, compositional combinations, and interfacial quality, and are generally complex. In this contribution, we explored the use of Ag ultrathin overlayers on annealed . A method for preparing magnetic layers with different levels of enhanced magnetic anisotropy energy was developed. The method essentially involves simply modifying the contact area of the metallic/magnetic interface. A rougher interface results in a larger contact area between the Ag and Ni layers, resulting in an increase in magnetic anisotropy energy. Moreover, post-annealing treatments led to the segregation of Ni atoms, thus making the enhancement in the coercive force even more efficient. A model permits an understanding of the contact area and a strategy for enhancing the magnetic anisotropy energy and the coercive force was developed. Our approaches and the developed model promise to be helpful in terms of developing potential applications of ultrathin magnetic layers in the area of spintronics.

In-Situ Preparation and Magnetic Properties of Fe3O4/WOOD Composite

NASA Astrophysics Data System (ADS)

Gao, Honglin; Zhang, Genlin; Wu, Guoyuan; Guan, Hongtao

2011-06-01

Fe3O4/wood composite, a magnetic material, was prepared by In-situ chemosynthesis method at room temperature. The X-ray diffraction (XRD) shows that the average partical size of Fe3O4 was about 14 nm. The magnetic properties of the resulting composites were investigated by vibrating sample magnetometer (VSM). The composites have saturation magnetization (Ms) values from 4.7 to 25.3 emu/g with the increase of weight percent gains (WPG) of the wood for the composites, but coercive forces (Hc) are invariable, which is different from the magnetic materials reported before. It may be due to the fact that the interaction between wood and Fe3O4 becomes stronger when less of Fe3O4 particles are introduced in the composition, and this also changes the surface anisotropy (Ks) of the magnetism. A structural characterization by Fourier transform infrared (FTIR) proved the interaction between Fe3O4 particles and wood matrix, and it also illustrates that this interaction influences the coercive force of the composite.

Exchange spring in A1/L1{sub 0} FePt composite and its application in magnetic force microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Guoqing, E-mail: gqli@swu.edu.cn; Zhu, Yanyan, E-mail: zhubai@swu.edu.cn; Zhang, Yong

2015-02-23

This paper reported fabrication of Fe{sub x}Pt{sub 100-x} films with (001) epitaxy on MgO(100) substrates. The atomic percentage of Fe was changed within the range of x = 10–85 in order to search the optimal atomic ratio for achieving both high and isotropic-like coercivity. It was found that the Fe{sub 60}Pt{sub 40} film exhibited large coercivities exceeding 5 kOe along both in-plane and out-of-plane directions due to the formation of A1/L1{sub 0} FePt composite. A penta-domain model for hard/soft/hard exchange spring system was proposed to interpret the anomalous magnetization behaviors observed in Fe{sub 60}Pt{sub 40} sample. By using Fe{sub 60}Pt{sub 40} asmore » the magnetic coating layer on a probe of magnetic force microscope, the flux changes at a linear density of 1000 kfci could be readily observed at a resolution of ∼13 nm.« less

Effect of stress on amorphous bent cores

NASA Astrophysics Data System (ADS)

Saito, Akihiko; Yamamoto, Ken-ichi; Kunimori, Osamu

1992-07-01

The effect of stress on bent amorphous cores with positive magnetostriction has been investigated. Tension has been applied to the ribbon while winding into the toroid to improve the magnetic properties of the core. The properties of the coercive force of the tension winding core due to applied tension have been made clear from the observation of the domain structure.

Magnetic Force Microscopy Study of Zr 2 Co 11 -Based Nanocrystalline Materials: Effect of Mo Addition

DOE PAGES

Yue, Lanping; Jin, Yunlong; Zhang, Wenyong; ...

2015-01-01

Tmore » he addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr 2Co 11-based nanocrystalline permanent magnets. he effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr 16Co 84-xMo x( x = 0 , 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. he coercivity of the samples increases with the increase in Mo content ( x ≤ 1.5 ). he maximum energy product ( B H ) max increases with increasing x from 0.5 MGOe for x = 0 to a maximum value of 4.2 MGOe for x = 1.5 . he smallest domain size with a relatively short magnetic correlation length of 128 nm and largest root-mean-square phase shift Φ rms value of 0.66° are observed for the x = 1.5 . he optimal Mo addition promotes magnetic domain structure refinement and thus leads to a significant increase in coercivity and energy product in this sample.« less

Magnetic Force Microscopy Study of Zr 2 Co 11 -Based Nanocrystalline Materials: Effect of Mo Addition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yue, Lanping; Jin, Yunlong; Zhang, Wenyong

Tmore » he addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr 2Co 11-based nanocrystalline permanent magnets. he effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr 16Co 84-xMo x( x = 0 , 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. he coercivity of the samples increases with the increase in Mo content ( x ≤ 1.5 ). he maximum energy product ( B H ) max increases with increasing x from 0.5 MGOe for x = 0 to a maximum value of 4.2 MGOe for x = 1.5 . he smallest domain size with a relatively short magnetic correlation length of 128 nm and largest root-mean-square phase shift Φ rms value of 0.66° are observed for the x = 1.5 . he optimal Mo addition promotes magnetic domain structure refinement and thus leads to a significant increase in coercivity and energy product in this sample.« less

Exploring the link between institutional pressures and environmental management systems effectiveness: An empirical study.

PubMed

Daddi, Tiberio; Testa, Francesco; Frey, Marco; Iraldo, Fabio

2016-12-01

Institutional theory has been widely debated by scholars. A part of literature examines how institutional pressures act on company choices regarding proactive environmental strategies. However, the institutional perspective has still not completely clarified the influence of these pressures on the effectiveness of environmental management systems (EMSs) in achieving goals in terms of eco-innovation, competitiveness and corporate reputation. This paper analyses the role played by coercive, mimetic and normative forces in stimulating innovative and competitive responses by firms with an environmental certification. Using the results of a survey on 242 European EMAS-registered organisations, the paper highlights the more positive influence of mimetic and normative pressures than coercive ones. The paper contributes to the literature debate on EMSs analysed through the lens of institutional theory. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Use of Coercive Interventions in Mental Health Care in Germany and the Netherlands. A Comparison of the Developments in Two Neighboring Countries

PubMed Central

Steinert, Tilman; Noorthoorn, Eric O.; Mulder, Cornelis L.

2014-01-01

In this review, we compare the use of coercion in mental health care in Germany and in the Netherlands. Legal frameworks and published data on involuntary commitment, involuntary medication, seclusion, and restraint are highlighted as well as the role of guidelines, training, and attitudes held by psychiatrists and the public. Legal procedures regulating involuntary admission and commitment are rather similar, and so is the percentage of involuntary admissions and the rate per 100,000 inhabitants. However, opposing trends can be observed in the use of coercive interventions during treatment, which in both countries are considered as a last resort after all other alternative approaches have failed. In the Netherlands, for a long time seclusion has been considered as preferred intervention while the use of medication by force was widely disapproved as being unnecessarily invasive. However, after increasing evidence showed that number and duration of seclusions as well as the number of aggressive incidents per admission were considerably higher than in other European countries, attitudes changed within recent years. A national program with spending of 15 million € was launched to reduce the use of seclusion, while the use of medication was facilitated. A legislation is scheduled, which will allow also outpatient coercive treatment. In Germany, the latter was never legalized. While coercive treatment in Germany was rather common for involuntarily committed patients and mechanical restraint was preferred to seclusion in most hospital as a containment measure, the decisions of the Constitutional Court in 2011 had a high impact on legislation, attitudes, and clinical practice. Though since 2013 coercive medication is approvable again under strict conditions, it is now widely perceived as very invasive and last resort. There is evidence that this change of attitudes lead to a considerable increase of the use of seclusion and restraint for some patients. PMID:25309893

Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saleh, Muad; Cao, Yue; Edwards, Danny J.

Magnetic Barkhausen noise (MBN), hysteresis measurements, first order reversal curves (FORC), Vickers microhardness, and Transmission Electron Microscopy (TEM) analyses were performed on Fe-1wt.%Cu (Fe-Cu) samples isothermally aged at 700°C for 0.5 – 25 hours to obtain samples with different sized Cu precipitates and dislocation structures. Fe-Cu is used to simulate the thermal and irradiation-induced defects in copper-containing nuclear reactor materials such as cooling system pipes and pressure vessel materials. The sample series showed an initial increase followed by a decrease in hardness and coercivity with aging time, which is explained by Cu precipitates formation and growth as observed by TEMmore » measurements. Further, the MBN envelope showed a continuous decrease in its magnitude and the appearance of a second peak with aging. Also, FORC diagrams showed multiple peaks whose intensity and location changed for different aging time. The changes in FORC diagrams are attributed to combined changes of the magnetic behavior due to Cu precipitate characteristics and dislocation structure. A second series of samples aged at 850°C, which is above the solid solution temperature of Fe-Cu, was studied to isolate the effects of dislocations. These samples showed a continuous decrease in MBN amplitude with aging time although the coercivity and hardness did not change significantly. The decrease of MBN amplitude and the appearance of the second MBN envelope peak are attributed to the changes in dislocation density and structure. This study shows that the effect of dislocations on MBN and FORC of Fe-Cu materials can vary significantly and should be considered in interpreting magnetic signatures.« less

Planning for Action: Campaign Concepts and Tools

DTIC Science & Technology

2012-08-01

142 10-15. Stability Mechanisms – Army .................................... 143 10-16. Stability Mechanisms – Joint...defeat mechanisms, which focus 143 the destructive and coercive capabilities of the force to provide security and public order and safety for...Matthew B. Ridgway. GEN Ridgway successfully led the 82d Airborne Division and XVIII Airborne Corps in the ETO during World War II and Eighth (US

Magnetic interactions and reversal mechanisms in Co nanowire and nanotube arrays

NASA Astrophysics Data System (ADS)

Proenca, M. P.; Sousa, C. T.; Escrig, J.; Ventura, J.; Vazquez, M.; Araujo, J. P.

2013-03-01

Ordered hexagonal arrays of Co nanowires (NWs) and nanotubes (NTs), with diameters between 40 and 65 nm, were prepared by potentiostatic electrodeposition into suitably modified nanoporous alumina templates. The geometrical parameters of the NW/NT arrays were tuned by the pore etching process and deposition conditions. The magnetic interactions between NWs/NTs with different diameters were studied using first-order reversal curves (FORCs). From a quantitative analysis of the FORC measurements, we are able to obtain the profiles of the magnetic interactions and the coercive field distributions. In both NW and NT arrays, the magnetic interactions were found to increase with the diameter of the NWs/NTs, exhibiting higher values for NW arrays. A comparative study of the magnetization reversal processes was also performed by analyzing the angular dependence of the coercivity and correlating the experimental data with theoretical calculations based on a simple analytical model. The magnetization in the NW arrays is found to reverse by the nucleation and propagation of a transverse-like domain wall; on the other hand, for the NT arrays a non-monotonic behavior occurs above a diameter of ˜50 nm, revealing a transition between the vortex and transverse reversal modes.

"He Could Scare Me Without Laying a Hand on Me": Mothers' Experiences of Nonviolent Coercive Control During Marriage and After Separation.

PubMed

Crossman, Kimberly A; Hardesty, Jennifer L; Raffaelli, Marcela

2016-03-01

Studies demonstrate the negative effects of violent coercive control but few examine coercive control without violence. This study describes the characteristics of nonviolent coercive control among 8 divorcing mothers and compares them with 47 mothers who experienced violent coercive control or no violence/no control. Mothers with nonviolent coercive control reported more coping strategies, risk, harassment, and perceived threat than mothers with no violence/no control; similar levels of fear and control during marriage as mothers with violent coercive control; and more postseparation fear than both groups. Findings highlight the need to include nonviolent coercive control in screening methods and research measures. © The Author(s) 2015.

Personality and organizational influences on aerospace human performance

NASA Technical Reports Server (NTRS)

Helmreich, Robert L.

1989-01-01

Individual and organizational influences on performance in aerospace environments are discussed. A model of personality with demonstrated validity is described along with reasons why personality's effects on performance have been underestimated. Organizational forces including intergroup conflict and coercive pressures are also described. It is suggested that basic and applied research in analog situations is needed to provide necessary guidance for planning future space missions.

Effect of sintering in a hydrogen atmosphere on the density and coercivity of (Sm,Zr)(Co,Cu,Fe)Z permanent magnets

NASA Astrophysics Data System (ADS)

Burkhanov, G. S.; Dormidontov, N. A.; Kolchugina, N. B.; Dormidontov, A. G.

2018-04-01

The effect of heat treatments in manufacturing (Sm,Zr)(Co,Cu,Fe)Z-based permanent magnets sintered in a hydrogen atmosphere on their properties has been studied. It was shown that the dynamics of the magnetic hardening of the studied magnets during heat treatments, in whole, corresponds to available concepts of phase transformations in five-component precipitation-hardened SmCo-based alloys. Peculiarities of the studied compositions consist in the fact that the coercive force magnitude of magnets quenched from the isothermal aging temperature is higher by an order of magnitude than those available in the literature. It was noted that, in using the selected manufacturing procedure, the increase in the density of samples does not finish at the sintering stage but continues in the course of solid-solution heat treatment.

Psychological Coercion in Human Trafficking: An Application of Biderman's Framework.

PubMed

Baldwin, Susie B; Fehrenbacher, Anne E; Eisenman, David P

2015-09-01

This study examined coercive conditions experienced by trafficked persons in the context of Biderman's theory of coercion. We conducted semi-structured interviews with 12 adult women trafficked into Los Angeles County, from 10 countries, for domestic work and/or sex work. Participants described health problems they experienced in relation to their trafficking experience and their perceptions of conditions that caused health problems. Utilizing a framework analysis approach, we analyzed themes using Biderman's framework. Participants reported experiencing the range of nonphysical coercive tactics outlined by Biderman, including isolation, monopolization of perception, induced debility or exhaustion, threats, occasional indulgences, demonstration of omnipotence, degradation, and enforcement of trivial demands. Our analysis demonstrates how these coercion tactics reinforced the submission of trafficked persons to their traffickers even in the absence of physical force or restraints. Such psychological abuse creates extreme stress that can lead to acute and chronic, physical and mental health problems. © The Author(s) 2014.

Magnetic Force Switches for Magnetic Fluid Micromixing

NASA Astrophysics Data System (ADS)

Wei, Zung-Hang; Lee, Chiun-Peng; Lai, Mei-Feng

2010-01-01

A magnetic fluid micromixer with energy-saving magnetic force switches that can manipulate the magnetic fluid flow is proposed. The micromixer of high mixing efficiency uses single-domain micro magnets that have strong magnetic anisotropy to produce the magnetic force for the mixing. By altering the magnetization directions of the magnets that have different aspect ratios and coercivities, open and closed magnetic fluxes can be produced around each magnet cluster. For open magnetic flux, the mixing efficiency is numerically found to increase with the saturation magnetization of the magnets. On the contrary, the magnet clusters barely affects the mixing efficiency in the case of closed magnetic flux. Due to the different magnetic forces produced in open and closed magnetic fluxes, the magnetic fluid mixing can be switched on and off.

Rethinking Coercive Control.

PubMed

Stark, Evan

2009-12-01

The critical appraisals of Coercive Control focus largely on what my analysis implies for intervention, a matter to which the book devotes only limited space. In this reply, I reiterate core concepts in the book and acknowledge that much more work is needed to translate the realities of coercive control into practical legal and advocacy strategies. I review how coercive control differs from partner assaults and so why it merits a distinct response; the extent to which coercive control targets gender identity; the wisdom of complementing the focus on violence with an emphasis on male domination, sexual inequality and personal liberty; what this implies for shelters and the law; why sexual inequality differentiates coercive control from female partner abuse of men; how sexual equality can be both cause and antidote for coercive control; why I think an affirmative concept of freedom is essential to grasp the human rights violations inflicted by coercive control; and what it means to "story" coercive control by integrating women into the larger liberty narrative on which our national identity rests.

Study protocol for a cluster randomised controlled trial to assess the effectiveness of user-driven intervention to prevent aggressive events in psychiatric services.

PubMed

Välimäki, Maritta; Yang, Min; Normand, Sharon-Lise; Lorig, Kate R; Anttila, Minna; Lantta, Tella; Pekurinen, Virve; Adams, Clive E

2017-04-04

People admitted to psychiatric hospitals with a diagnosis of schizophrenia may display behavioural problems. These may require management approaches such as use of coercive practices, which impact the well-being of staff members, visiting families and friends, peers, as well as patients themselves. Studies have proposed that not only patients' conditions, but also treatment environment and ward culture may affect patients' behaviour. Seclusion and restraint could possibly be prevented with staff education about user-centred, more humane approaches. Staff education could also increase collaboration between patients, family members and staff, which may further positively affect treatment culture and lower the need for using coercive treatment methods. This is a single-blind, two-arm cluster randomised controlled trial involving 28 psychiatric hospital wards across Finland. Units will be randomised to receive either a staff educational programme delivered by the team of researchers, or standard care. The primary outcome is the incidence of use of patient seclusion rooms, assessed from the local/national health registers. Secondary outcomes include use of other coercive methods (limb restraint, forced injection, and physical restraint), service use, treatment satisfaction, general functioning among patients, and team climate and employee turn-over (nursing staff). The study, designed in close collaboration with staff members, patients and their relatives, will provide evidence for a co-operative and user-centred educational intervention aiming to decrease the prevalence of coercive methods and service use in the units, increase the functional status of patients and improve team climate in the units. We have identified no similar trials. ClinicalTrials.gov NCT02724748 . Registered on 25 th of April 2016.

The Paleolimnological Record of the North Atlantic Oscillation: Magnetic Properties and Diatom Counts from Hemlock and Conesus Lakes, Western New York State

NASA Astrophysics Data System (ADS)

Chaisson, W. P.; Arnold, M. R.; Cottrell, R. D.

2002-05-01

Between 1900 and 1930 CE when the NAO index showed large amplitude positive excursions, but the AO index varied at very small amplitudes, drought conditions frequently prevailed in western New York state according the Palmer Drought Index (PDI). Since 1970, when both the NAO and the AO indices show large and progressively increasing positive excursions, the PDI has been generally positive, indicating moisture surpluses in the region. Magnetic properties, including coercivity of remanence, have been measured and the diatoms have been enumerated in sediments from two gravity cores collected from Hemlock and Conesus Lakes. The sediments date from ~1875 CE in the Hemlock core and ~1923 CE in the Conesus core. Variations in magnetic grain-size are interpreted from the coercivity of remanence, with lower coercivity of remanence associated with large grain size. The primary productivity of lakes is interpreted from the Lake Trophic Status Index (LTSI), which is calculated based on known ecologies of several diatom species. In both lakes we find that larger magnetic grain size is associated with greater productivity in the lakes. In the Hemlock core, through the interval corresponding to 1913-1943 coercivity of remanence values declined to 281-259 Oersteds, from late 19th century values that were >350 Oersteds. The bottom of the Conesus core (1923-1938 CE) has the lowest coercivity of remanance values in the record (309-317 Oersteds). LTSI values in the Hemlock samples increase as remanence of coercivity values decline between 1888 and 1920 CE. This reflects an increase in the abundance of the mesoeutrophic Tabellaria fenestrata during this interval. In the Conesus samples the agreement between coercivity of remanence and LTSI is quite close. The range of variation in both LTSI and magnetic grain size is smaller in Conesus than in Hemlock Lake. The diatom assemblage is also quite different in Conesus, dominated by eutrophic Aulacosiera granulata, which are rare or absent at Hemlock Lake. The Hemlock basin is much steeper than than that of Conesus and its water level fluctuates more extremely because it is the reservoir for the city of Rochester. Hemlock Lake is oligotrophic and its drainage basin is heavily forested and lightly populated. Conesus Lake is eutrophic, its shores lined with cottages and the basin is heavily agricultural. In spite of these differences in both natural conditions and anthropogenic factors, the LTSI and magnetic measurements of the two lakes share variance, ostensibly forced by regional climate change. Initial results suggest that the shared component of variance in these proxy indicators can predict variations in regional drought intensity. Regional drought intensity, in turn, seems associated with an uncoupling of AO and NAO variation.

The Ethnic Factor in the Soviet Armed Forces. The Muslim Dimension

DTIC Science & Technology

1991-01-01

Muslim conscripts into effective soldiers. The types of problems that a Muslim conscript presents for the Soviet military can be narrowed to two categories ... categories : ability and reliability. ETHNICITY AND DEMOGRAPHICS The major Soviet Muslim ethnic groups are creations of the Soviet regime, dating back to...avoid such embarrassments in the future. viii SOVIET MILITARY REFORM The predominantly coercive type of compliance previously used by the Soviet military

Getting to No (Nuclear Weapons) with Iran: Will Coercive Diplomacy Work?

DTIC Science & Technology

2013-12-10

elucidates additional options to better address strategic ends, but with greater risk. Unless a grand bargain is attainable, the U.S. must likely accept...strategic ends, but likely with a substantial increase in risk. Unless an unspoken grand bargain is attainable, the U.S. must likely accept...adroit and vigilant application of counter- force at a series of constantly shifting geographical and political points, corresponding to the shifts

Conflict Containment in the Balkans: Testing Extended Deterrence.

DTIC Science & Technology

1995-03-01

STATEMENT 12b. DISTRIBUTION CODE Approved for public release; distribution is unlimited. 13. ABSTRACT This thesis critically analyzes a prominent theoretical...Containment 15. NUMBER OF in the Balkans; Deterrence; Coercive Diplomacy; Balance of Forces. PAGES: 161 16. PRICE CODE 17. SECURITY CLASSIFI- 18. SECURITY...Department of National Security Affai sAccesion For NTIS CRA&I DTtC TAB Unannounced Justifca ........... By- Distribution Availability Codes Avail and/or Dist

Hollow Threats: Why Coercive Diplomacy Fails

DTIC Science & Technology

2015-06-01

IDE from the Curso del Estado Mayor de las Fuerzas Armadas in Madrid, Spain. Maj Schore has a bachelor’s degree in Economics from the University...this element presupposes that the nature of a liberal democracy not only reduces its credibility to administer a severe level of hurt, but damages...of resistance increased Aidid’s ability to portray his forces as national liberators and augmented his support among the Somali people.40 This

The Requirement for U.S. Army Special Forces to Conduct Interrogation

DTIC Science & Technology

2012-06-01

SCHARFF .............93  APPENDIX D.  “SUGGESTIONS FOR JAPANESE INTERPRETERS BASED ON WORK IN THE FIELD” BY SHERWOOD MORAN ...............107  INITIAL...reluctant to risk their men simply to capture Japanese soldiers—soldiers they were convinced would never disclose valuable intelligence.44 Through a...only the most severe coercive measures of interrogation would convince a captured Japanese soldier to divulge information. Moran believed “strong

Thermal treatment to enhance saturation magnetization of superparamagnetic Ni nanoparticles while maintaining low coercive force

NASA Astrophysics Data System (ADS)

Ishizaki, Toshitaka; Yatsugi, Kenichi; Akedo, Kunio

2018-05-01

Superparamagnetic nanoparticles capped by insulators have the potential to decrease eddy current and hysteresis losses. However, the saturation magnetization ( M s) decreases significantly with decreasing the particle size. In this study, superparamagnetic Ni nanoparticles having the mean size of 11.6 ± 1.8 nm were synthesized from the reduction of Ni(II) acetylacetonate in oleylamine with the addition of trioctylphosphine, indicating the coercive force ( H c) less than 1 Oe. Thermal treatments of the Ni nanoparticles were investigated as a method to enhance the M s. The results indicated that the M s was enhanced by an increase of the Ni mass ratio with increasing thermal treatment temperature. However, the decomposition behavior of the capping layers indicated that their alkyl chains actively decomposed at temperatures above 523 K to form Ni3P via reaction between Ni and P, resulting in particle growth with a significant increase in the H c. Therefore, the optimal temperature was determined to be 473 K, which increased the Ni ratio without formation of Ni3P while maintaining particle sizes with superparamagnetic properties. Further, the M s could be improved by 22% (relative to the as-synthesized Ni nanoparticles) after thermal treatment at 473 K while maintaining the H c to be less than 1 Oe.

Intersectional Discrimination of Romani Women Forcibly Sterilized in the Former Czechoslovakia and Czech Republic

PubMed Central

Albert, Gwendolyn

2017-01-01

Abstract This paper reviews domestic and international activism seeking justice for Romani and other women harmed by coercive, forced, and involuntary sterilization in the former Czechoslovakia and Czech Republic. Framed by Michel Foucault’s theory of biopower, it summarizes the history of these abuses and describes human rights campaigns involving domestic and international litigation, advocacy, and grassroots activism, as well as the responses of the Czech governments. The paper describes how legal and policy work during the past decade has led to recognition of coercive, forced, and involuntary sterilization as a present-day human rights issue worldwide, to the adoption of new guidelines on female sterilization, and to a joint statement on the issue by seven UN agencies. Relying on academic literature, reports by domestic and international human rights groups, state investigations, judgments from Czech courts and the European Court of Human Rights (ECHR), media reports, and the experience of the authors, who have been allies of the Romani women harmed in the Czech Republic since 2005 and 2012, respectively, the paper describes the current state of play with respect to achieving redress for them, including current conceptual, legal, political, and social obstacles and their antecedents in 20th century notions of population control. PMID:29302160

To enhance the efficiency of a power supply circuit by the use of Fe-P-B-Nb-type ultralow loss glassy metal core

NASA Astrophysics Data System (ADS)

Matsumoto, H.; Urata, A.; Yamada, Y.; Makino, A.

2009-04-01

The inductor in a power supply is required to be capable of dealing satisfactorily with the high-current supply and to improve the power loss characteristic. A novel glassy metal powder with a chemical composition Fe77P7B13Nb3 features both a high saturated magnetic flux density of 1.3 T and a low coercive force of 2.0 A/m, which has a stable amorphous structure suitable for glassy metal composite cores. Hence there is no magnetic saturation even under a high-current supply, and it is confirmed to have significantly low magnetic loss resulting from the low coercive force. As a result of using the glassy metal alloy Fe77P7B13Nb3 powder in an inductor core, we have achieved improvement in power supply efficiency by up to roughly 2.0%. Moreover, the reduction in the standby power requirement by the improvement in the power supply efficiency in the low load current case, where the core loss occupies a high ratio in the entire loss, can be expected. Additionally, heat generation in a core is suppressed by using the low loss powder, and it becomes easy to design a temperature rise in the entire power supply circuit.

Intersectional Discrimination of Romani Women Forcibly Sterilized in the Former Czechoslovakia and Czech Republic.

PubMed

Albert, Gwendolyn; Szilvasi, Marek

2017-12-01

This paper reviews domestic and international activism seeking justice for Romani and other women harmed by coercive, forced, and involuntary sterilization in the former Czechoslovakia and Czech Republic. Framed by Michel Foucault's theory of biopower, it summarizes the history of these abuses and describes human rights campaigns involving domestic and international litigation, advocacy, and grassroots activism, as well as the responses of the Czech governments. The paper describes how legal and policy work during the past decade has led to recognition of coercive, forced, and involuntary sterilization as a present-day human rights issue worldwide, to the adoption of new guidelines on female sterilization, and to a joint statement on the issue by seven UN agencies. Relying on academic literature, reports by domestic and international human rights groups, state investigations, judgments from Czech courts and the European Court of Human Rights (ECHR), media reports, and the experience of the authors, who have been allies of the Romani women harmed in the Czech Republic since 2005 and 2012, respectively, the paper describes the current state of play with respect to achieving redress for them, including current conceptual, legal, political, and social obstacles and their antecedents in 20th century notions of population control.

Magnetic properties of the surface layer and its magnetic interaction with the interior of Nd-Fe-B sintered magnets

NASA Astrophysics Data System (ADS)

Kobayashi, Kurima; Nakamura, Michi-hide; Urushibata, Kimiko

2015-05-01

The magnetization and demagnetization mechanisms in the mechanically polished surface layers (SL) of the c-plane and a-b plane of Nd-Fe-B sintered magnets were investigated. The magnetic interaction between the SL and the interior of the magnet was clarified by using vibrating sample magnetometer measurements of a whole sample and magneto-force microscopy observations of the domain structure of the SL layer. The polishing eliminated the Nd-rich grain boundary phases, which was only about 2 nm thick, from the SL crystal grains in the sintered magnets. The a-b plane polishing caused the independent magnetic reversal of the a-b plane SL, which was about 5.5 μm thick, as in the platy samples. The coercivities (μ0Hc) of the SL were less than 0.3 T. In contrast, the c-plane polishing did not produce independent magnetic reversal of the SL, although the coercivity of bulk samples was clearly decreased by the formation of the c-plane SL. The grains in the SL should form clusters that alter the demagnetizing factors, depending on the shape of cluster as a magnetic unit. The magnetic interaction among the SL crystal grains is expected to play an important role in the coercivity mechanism of Nd-Fe-B sintered magnets.

Iron-platinum-coated carbon nanocone probes on tipless cantilevers for high resolution magnetic force imaging.

PubMed

Chen, I-Chen; Chen, Li-Han; Gapin, Andrew; Jin, Sungho; Yuan, Lu; Liou, Sy-Hwang

2008-02-20

High coercivity iron-platinum-coated carbon nanocones (CNCs) have been fabricated for magnetic force microscopy (MFM) by direct-current plasma-enhanced chemical vapor deposition growth of nanocones on tipless cantilevers followed by sputtering and annealing of the FePt film. The FePt-coated CNC probe has many localized magnetic stray fields due to the high-aspect-ratio geometry and small radius of the tip. The MFM imaging on magnetic recording media was performed using CNC probes and compared with the imaging by FePt-coated silicon probes. An image with 20 nm lateral resolution has been demonstrated.

Consequences of thermal acclimation for the mating behaviour and swimming performance of female mosquito fish.

PubMed

Wilson, Robbie S; Condon, Catriona H L; Johnston, Ian A

2007-11-29

The mating system of eastern mosquito fish (Gambusia holbrooki) is dominated by male sexual coercion, where all matings are forced and females never appear to cooperate and actively avoid all attempts. Previous research has shown that male G. holbrooki offer a model system for examining the benefits of reversible thermal acclimation for reproductive success, but examining the benefits to female avoidance behaviour has been difficult. In this study, we examined the ability of non-male-deprived female G. holbrooki to avoid forced-coercive matings following acclimation to either 18 or 30 degrees C for six weeks (12h light:12h dark photoperiod). Thermal acclimation of burst and sustained swimming performance was also assessed, as these traits are likely to underlie their ability to avoid forced matings. There was no influence of thermal acclimation on the burst swimming performance of female G. holbrooki over the range 18-30 degrees C; however, sustained swimming performance was significantly lower in the warm- than the cool-acclimation group. For mating behaviour, we tested the hypothesis that acclimation would enhance the ability of female G. holbrooki to avoid forced matings at their host acclimation temperature relative to females acclimated to another environment. However, our hypothesis was not supported. The rate of copulations was almost three times greater for females acclimated to 30 degrees C than 18 degrees C when tested at 30 degrees C, indicating that they possess the ability to alter their avoidance behaviour to 'allow' more copulations in some environments. Coupled with previous studies, female G. holbrooki appear to have greater control on the outcome of coercive mating attempts than previously considered and can alter their propensity to receive forced matings following thermal acclimation. The significance of this change in female mating-avoidance behaviours with thermal acclimation remains to be explored.

Women and men's use of coercive control in intimate partner violence.

PubMed

Robertson, Kirsten; Murachver, Tamar

2011-01-01

This study examined the relationship between coercive control and intimate partner violence (IPV) for men and women and for targets and perpetrators. One hundred and seventy-two participants (85 men, 87 women) recruited from three samples reported on their own and their partner's behavior. IPV was measured using the Revised Conflict Tactics Scale (CTS2). Coercive control was measured using modified items from the Psychological Maltreatment of Women Inventory (PMWI). Coercive control was associated with IPV, and this relationship was similar for men and women across the three samples. In fact, coercive control was predominantly reciprocal in nature, with women and men reporting both receiving and perpetrating controlling behaviors. Overall, coercive controlling behaviors were characteristic of individuals within violent relationships, regardless of their physical abuse status. The experience of violence, rather than gender, was the best predictor of coercive control.

The Iranian Revolution: A Case Study in Coercive Power Consolidation

DTIC Science & Technology

1994-03-01

all potential competition . This was accomplished by waging a multi-pillared policy aimed at ethnic minorities, political opposition groups and...reported back to United States Secretary of Defense Harold Brown that working with the Iranian military was difficult due to the compartmentation of the...military leader such as General Djam to hold the armed forces together, fearing that such a situation would work against him if he returned to Iran.° He

Magnetic properties of iron oxide photolytically produced from Fe(CO)5 impregnated porous glass

NASA Astrophysics Data System (ADS)

Borelli, N. F.; Morse, D. L.; Schreurs, J. W. H.

1983-06-01

This article discusses the magnetic properties observed in porous glasses impregnated with metal carbonyls after exposure to light. In the photolyzed and consolidated glasses both superparamagnetic and single domain ferrimagnetic particles were found to be present, with the single domain particles having an exceedingly high coercive force. The concentration ratio between superparamagnetic and single domain particles depends strongly on temperature. An analysis of the observed phenomena is given.

The Coercive Sterilization of Aboriginal Women in Canada

ERIC Educational Resources Information Center

Stote, Karen

2012-01-01

This paper considers the coercive sterilization of Aboriginal women in legislated and non-legislated form in Canada. I provide an historical and materialist critique of coercive sterilization. I argue for coercive sterilization to be understood as one of many policies employed to undermine Aboriginal women, to separate Aboriginal peoples from…

The origin of coercivity decrease in fine grained Nd-Fe-B sintered magnets

NASA Astrophysics Data System (ADS)

Li, W. F.; Ohkubo, T.; Hono, K.; Sagawa, M.

2009-04-01

Microstructures of fine grained Nd-Fe-B sintered magnets that were produced by the pressless process were investigated to understand the origin of the sudden coercivity decrease below a certain grain size. The intrinsic coercivity is inversely proportional to ln D2 with the highest coercivity of 17 kOe at D˜4.5 μm, below which the coercivity drops as the grain size decreases. We found that the degradation of the coercivity of the magnet with a grain size of 3 μm was mainly caused by the inhomogeneous distribution of fcc-Nd oxide whose volume fraction increased with respect to the dhcp Nd-rich phase.

Faculty Perceptions of and Experiences with Students' Use of Coercive Power

ERIC Educational Resources Information Center

Kuhn, Kristine L.

2016-01-01

The purpose of this basic qualitative study was to understand how faculty perceive and experience students' use of coercive power in faculty-student relationships. Interviews were used to gather data from faculty members who had experienced students' use of coercive power. Data reveal that students' use of coercive power can negatively impact…

[Coercion in Psychiatry - a taboo?].

PubMed

Meise, Ullrich; Frajo-Apor, Beatrice; Stippler, Stippler; Wancata, Johannes

2011-01-01

History shows that the discussion concerning coercive measures against mentally ill is as old as psychiatry itself. The dilemma of psychiatry lies in its double role - having both a therapeutic and a regulatory function. Violence against sick and disabled people conflicts with the ethical principles of helping professions. This, however, is where the danger lies: that the violent parts of psychiatric work - which in the opinion of experts cannot be entirely avoided - are repressed or seen as taboo and are therefore more difficult to control. Comparisons between EU countries of the nature, frequency and duration of coercive measures are difficult because of the heterogeneity of regulation and differences in established practice. Scientific examination of this issue seems to be insufficient. There are only a few studies on important issues such as how patients rate these measures. An open and thorough debate about the meaning and meaninglessness of coercion and violence in psychiatric treatment would be necessary to prevent "routine violence" or the excessive use of force against the mentally ill.

Magnetic vortex state and multi-domain pattern in electrodeposited hemispherical nanogranular nickel films

NASA Astrophysics Data System (ADS)

Samardak, Alexander; Sukovatitsina, Ekaterina; Ognev, Alexey; Stebliy, Maksim; Davydenko, Alexander; Chebotkevich, Ludmila; Keun Kim, Young; Nasirpouri, Forough; Janjan, Seyed-Mehdi; Nasirpouri, Farzad

2014-12-01

Magnetic states of nickel nanogranular films were studied in two distinct structures of individual and agglomerated granules electrodeposited on n-type Si(1 1 1) surface from a modified Watts bath at a low pH of 2. Magnetic force microscopy and micromagnetic simulations revealed three-dimensional out-of-plane magnetic vortex states in stand-alone hemispherical granules and their arrays, and multi-domain patterns in large agglomerates and integrated films. Once the granules coalesce into small chains or clusters, the coercivity values increased due to the reduction of inter-granular spacing and strengthening of the magnetostatic interaction. Further growth leads to the formation of a continuous granulated film which strongly affected the coercivity and remanence. This was characterized by the domain wall nucleation and propagation leading to a stripe domain pattern. Magnetoresistance measurements as a function of external magnetic field are indicative of anisotropic magnetoresistance (AMR) for the continuous films electrodeposited on Si substrate.

Decomposing the permeability spectra of nanocrystalline finemet core

NASA Astrophysics Data System (ADS)

Varga, Lajos K.; Kovac, Jozef

2018-04-01

In this paper we present a theoretical and experimental investigation on the magnetization contributions to permeability spectra of normal annealed Finemet core with round type hysteresis curve. Real and imaginary parts of the permeability were determined as a function of exciting magnetic field (HAC) between 40 Hz -110 MHz using an Agilent 4294A type Precision Impedance Analyzer. The amplitude of the exciting field was below and around the coercive field of the sample. The spectra were decomposed using the Levenberg-Marquardt algorithm running under Origin 9 software in four contributions: i) eddy current; ii) Debye relaxation of magnetization rotation, iii) Debye relaxation of damped domain wall motion and iv) resonant type DW motion. For small exciting amplitudes the first two components dominate. The last two contributions connected to the DW appear for relative large HAC only, around the coercive force. All the contributions will be discussed in detail accentuating the role of eddy current that is not negligible even for the smallest applied exciting field.

Gendering Coercive Control.

PubMed

Anderson, Kristin L

2009-12-01

This article examines the theory of gender presented in Stark's Coercive Control: How Men Entrap Women in Personal Life. Stark suggests that gender is a form of structural inequality that makes women more vulnerable than men to the strategies of coercive control. However, Stark assumes rather than demonstrates that gendered structural inequality increases women's vulnerability. In this article, the author applies the multilevel theory of gender as identity, interaction, and social structure to document the multiple ways coercive control is gendered. The author argues that, to understand the gender dynamics of coercive control, researchers must examine the interactions across levels of gender. The author concludes with an assessment of the prospects and pitfalls of applying the concept of coercive control to renew the feminist social movement to end domestic violence.

An Alternative Approach: Examining Arguments Against Coercive Interrogation Techniques from a Biblical-Ethics Perspective

DTIC Science & Technology

2016-06-10

that CIT contradict the ethics of their faith. Considering that Christianity remains the religious tradition for the majority of U.S. military service...that Christianity remains the religious tradition for the majority of U.S. military service members, it is a worthy task to examine if a potentially...force in influencing the method by which a majority of its citizens make ethical judgments. In a 2010 national survey of religious preferences, 47.7

Electrodeposition and magnetic characterization of iron and iron-silicon alloys from the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate.

PubMed

Giridhar, Pulletikurthi; Weidenfeller, Bernd; El Abedin, Sherif Zein; Endres, Frank

2014-11-10

The electrodeposition of soft magnetic iron and iron-silicon alloys for magnetic measurements is presented. The preparation of these materials in 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py1,4]TfO, at 100 °C with FeCl2 and FeCl2 +SiCl4 was studied by using cyclic voltammetry. Constant-potential electrolysis was carried out to deposit either Fe or FeSi, and deposits of approximately 10 μm thicknesses were obtained. By using scanning electron microscopy and X-ray diffraction, the microstructure and crystallinity of the deposits were investigated. Grain sizes in the nanometer regime (50-80 nm) were found and the presence of iron-silicon alloys was verified. Frequency-dependent magnetic polarizations, coercive forces, and power losses of some deposits were determined by using a digital hysteresis recorder. Corresponding to the small grain sizes, the coercive forces are around 950-1150 A m(-1) and the power losses were at 6000 J m(-3), which is much higher than in commercial Fe(3.2 wt %)Si electrical steel. Below a polarization of 1.8 T, the power losses are mainly caused by domain wall movements and, above 1.8 T, by rotation of magnetic moments as well as domain wall annihilation and recreation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Defining and Predicting Pimps' Coerciveness Toward Sex Workers: Socialization Processes.

PubMed

Stalans, Loretta J; Finn, Mary A

2016-10-01

Prior research has found that pimps use both non-coercive and coercive management styles across and within market segments of the illicit sex trade. The current study is the first to examine the socialization processes underlying variation in the self-reported coerciveness of pimps. This study begins to fill a void in the almost non-existent research on pimps who are actively managing Internet-solicited sex workers, and adds to the sparse research on pimps' coerciveness. We extend Anderson's concepts of "street code" families, where respect is acquired through displaying physical violence and toughness, and "decent" families, where middle class values of avoiding unnecessary aggression and complying with the law prevail, to understand variation in the degree of coerciveness that pimps utilize toward sex workers. A purposive sample of 44 active pimps was obtained through referrals from selected pimps and through placing advertisements on Backpage, a website utilized by the illicit prostitution trade. Qualitative coding revealed a wide range of coercive control tactics such as supplying drugs, surveillance, and physical violence. Pimps who served as sex workers and those raised by parents who supported "the code of the street" reported use of a greater number of more severe coercive tactics. College-educated pimps, pimps operating business that charged fees of at least US$300, and those from "decent" families were more likely to use non-coercive management. These findings suggest that early prevention programs might address the "street code" mentality that contributes to coerciveness, and that "End Demand" policies need to recognize that many male pimps also have served as sex workers.

Nano spin-diodes using FePt-NDs with huge on/off current ratio at room temperature

PubMed Central

Makihara, Katsunori; Kato, Takeshi; Kabeya, Yuuki; Mitsuyuki, Yusuke; Ohta, Akio; Oshima, Daiki; Iwata, Satoshi; Darma, Yudi; Ikeda, Mitsuhisa; Miyazaki, Seiichi

2016-01-01

Spin transistors have attracted tremendous interest as new functional devices. However, few studies have investigated enhancements of the ON/OFF current ratio as a function of the electron spin behavior. Here, we found a significantly high spin-dependent current ratio—more than 102 at 1.5 V—when changing the relative direction of the magnetizations between FePt nanodots (NDs) and the CoPtCr-coated atomic force microscope (AFM) probe at room temperature. This means that ON and OFF states were achieved by switching the magnetization of the FePt NDs, which can be regarded as spin-diodes. The FePt magnetic NDs were fabricated by exposing a bi-layer metal stack to a remote H2 plasma (H2-RP) on ~1.7 nm SiO2/Si(100) substrates. The ultrathin bi-layers with a uniform surface coverage are changed drastically to NDs with an areal density as high as ~5 × 1011 cm−2. The FePt NDs exhibit a large perpendicular anisotropy with an out-of-plane coercivity of ~4.8 kOe, reflecting the magneto-crystalline anisotropy of (001) oriented L10 phase FePt. We also designed and fabricated double-stacked FePt-NDs with low and high coercivities sandwiched between an ultra-thin Si-oxide interlayer, and confirmed a high ON/OFF current ratio when switching the relative magnetization directions of the low and high coercivity FePt NDs. PMID:27615374

Influence of the particle size and intrinsic magnetic characteristics on the coercivity of sintered magnets

NASA Astrophysics Data System (ADS)

Turilli, G.; Paoluzi, A.; Lucenti, M.; Pareti, L.

1992-02-01

Using sintered specimens of Ba-hexaferrite powders as a model system, a study was made of the dependence of coercivity on the particle dimensions and on the temperature from RT up to the Curie temperature. The temperature behaviour of the coercive and anisotropy field are the same in single-domain particle specimens while they are rather different in polydomain particle specimens. However, the coercivity behaviour of both systems can be fitted well up to 350°C using a simple relation between Hc, HA, and Ms. Further contributions to the coercivity have to be taken into account at higher temperatures.

Fabrication of Material and Devices for Very High Density Information Storage.

DTIC Science & Technology

1986-11-24

IKawanishi, "Miagnetic anid opticeal propert I e of Co. I It substituted garnet films p~rep~ared by the lPE niethod and its ipplication to hlermtmt"Ile( i...medium. Highly Bi-substituted garnet films on glass and G( substrates were successfully RF sputtered and characterized by the group of M. Goni.1 The filns...writing due to the temperature dependence of the coercive force 11. Preparation of bismuth iron garnet films by ion bean sputtering onto GGG

Coercive Nuclear Campaigns in the 21st Century: Understanding Adversary Incentives and Options for Nuclear Escalation

DTIC Science & Technology

2013-01-01

powers  armed  with  nuclear  weapons   may   employ   those   weapons...balance   of   power   is   reversed.     Now  U.S.  military   forces   are   the   most  formidable,  and  potential...the   balance   of   power   helps   explain   why   the   United   States   now   seeks   to  

The psychohistorical roots of the American "Tea Party" Movement.

PubMed

Tilden, William W

2011-01-01

Extreme resistance to governmental taxation and authority is derived, according to Freud's theory of anal characterology, from premature and harshly coercive toilet training, in which a child is forced unfairly and against its will to surrender the products of his eliminations (which represent money, among other things, in the unconscious) to parental authority. Among these individuals anal eroticism plays a significant role in the psychogenesis of paranoia and conspiracy theorizing, which may represent a defense mechanism erected against repressed fears of passive submission.

Air Defense Options for Taiwan: An Assessment of Relative Costs and Operational Benefits

DTIC Science & Technology

2016-01-01

and analyzes them in comparison to current People’s Liberation Army ( PLA ) capabilities. It begins with a description of the PLA air- power threat and... PLA ) to easily counter. Still, air defense in a major war is only one possible category of demands for Taiwan’s air defenses. A variety of more-limited...high, the PLA could check Taiwan’s fighter aircraft if it chose. However, in coercive scenarios that feature very constrained use of force, Taiwan’s

Local structure of high-coercivity Fe-Ni-Al alloys

NASA Astrophysics Data System (ADS)

Menushenkov, A. P.; Menushenkov, V. P.; Chernikov, R. V.; Sviridova, T. A.; Grishina, O. V.; Sidorov, V. V.

2011-04-01

Results of hard magnetic Fe-Ni-Al alloys after various thermal processing local structure researches by method of EXAFS-spectroscopy with use of synchrotron radiation at temperature 77 K are presented. It is established, that during cooling a firm solution with critical speed reorganization of a local environment of nickel relative to quickly tempered sample owing to stratification of a firm solution is observed. The subsequent aging at 780°C practically restores local structure, characteristic for quickly tempered sample, keeping thus rather high coercitive force.

From antisocial behavior to violence: a model for the amplifying role of coercive joining in adolescent friendships.

PubMed

Van Ryzin, Mark J; Dishion, Thomas J

2013-06-01

Aggression is one of the more stable characteristics of child and adolescent development, and violent behavior in early adulthood is often foreshadowed by aggressive behavior in childhood and early adolescence. Considerable evidence has linked coercive family interactions to aggressive behavior in childhood, but less research has been conducted on the joint role of family and peer interaction in the escalation of aggression to violence in adulthood. We coded family interactions at age 12-13 and friendship interaction at age 16-17 in a multiethnic sample of youth and families. Violence in young adulthood (age 22-23) was measured using self-report, criminal records, and parent report. We tested the hypothesis that a process of 'coercive joining' in friendship interactions mediated the relationship between coercive family interactions and serious violence. We found that observed coercive joining in friendships at age 16-17 predicted early-adulthood violent behavior over and above an established tendency toward antisocial behavior. We also found that observed coercive family interactions at age 12 predicted early-adulthood violence, and that coercive joining with friends fully mediated this link. These results significantly extend coercion theory by suggesting that coercive joining in the context of peer groups is an additional mechanism by which coercive processes in the family are extended and amplified to violent behavior in early adulthood. Our findings suggest the importance of addressing both individual interpersonal skills and self-organizing peer groups when intervening to prevent violent behavior. © 2012 The Authors. Journal of Child Psychology and Psychiatry © 2012 Association for Child and Adolescent Mental Health.

[Coercive Measures in Child and Adolescent Psychiatry].

PubMed

Rabe, Silke C; Fegert, Jörg M; Krüger, Ulrich; Kölch, Michael

2017-01-01

Coercive Measures in Child and Adolescent Psychiatry To keep the use of coercive measures in child and adolescent psychiatry low or reduce them completely, there needs to be a specific knowledge of the starting point. The study provides an overview of the current situation using a systematic literature review of published studies from the European and the outer European regions between 2005 and 2015. In summary only twelve publications addressed the topic, differentiated in four studies from inner and eight studies from outer European countries. In the studies from Europe, girls in their late adolescence experienced coercive measures more often, whereas the outer European studies identified more boys in early school age. Regarding the diagnoses of the respective patients, no distinct trend could be identified, as coercive measures were applied with a range of different diagnoses. In the European studies, coercive measures were more often used with children and adolescents fitting in the ICD-10-category F9. Results point to a lack of empirical studies concerning coercive measures in the context of child and adolescent psychiatry. Besides, clinical practice between the countries varies tremendously, resulting in difficulties comparing the findings. One possibility to address these issues might be a central register for every kind of coercive measure, as it was introduced in Baden-Württemberg lately and is currently in development for North Rhine-Westphalia.

Coercivity Enhancement in Exchange Biased Bilayers

NASA Astrophysics Data System (ADS)

Leighton, C.

2001-03-01

The well-known enhancement in coercivity in ferromagnet / antiferromagnet bilayers has been studied in the model epitaxial system MnF2 / Fe. We have investigated how the coercivity depends on temperature, cooling field, layer thickness and interfacial disorder. In all cases a typical enhancement is observed on cooling below the Neel temperature of the antiferromagnet. However, for the case of positively exchange biased layers we observe an extra coercivity enhancement which occurs when the interface is deliberately driven to a situation of maximum magnetic frustration(C. Leighton, J. Nogues, B.J. Jonsson-Akerman and I.K. Schuller, Phys. Rev. Lett. 84 3466 (2000)). This situation is controlled by the magnitude of the cooling field, giving us an external parameter through which we can vary the coercivity. We propose a model where a frustrated interface provides local energy minima which effectively pin domain walls leading to an increase in coercivity. We further examine the ferromagnet thickness dependence of the effect as a probe of the coercive mechanisms(Z. Li and S. Zhang, Phys. Rev. B61 R14897 (2000) ; S. Zhang et al J. Mag. Mag. Mat. 198-199 468 (1999)). Work supported by the US DoE and the NSF.

Mesoscopic bar magnet based on ε-Fe2O3 hard ferrite.

PubMed

Ohkoshi, Shin-Ichi; Namai, Asuka; Yamaoka, Takehiro; Yoshikiyo, Marie; Imoto, Kenta; Nasu, Tomomichi; Anan, Shizuka; Umeta, Yoshikazu; Nakagawa, Kosuke; Tokoro, Hiroko

2016-06-07

Ferrite magnets have a long history. They are used in motors, magnetic fluids, drug delivery systems, etc. Herein we report a mesoscopic ferrite bar magnet based on rod-shaped ε-Fe2O3 with a large coercive field (>25 kOe). The ε-Fe2O3-based bar magnet is a single crystal with a single magnetic domain along the longitudinal direction. A wide frequency range spectroscopic study shows that the crystallographic a-axis of ε-Fe2O3, which corresponds to the longitudinal direction of the bar magnet, plays an important role in linear and non-linear magneto-optical transitions, phonon modes, and the magnon (Kittel mode). Due to its multiferroic property, a magnetic-responsive non-linear optical sheet is manufactured as an application using an ε-Fe2O3-based bar magnet, resin, and polyethylene terephthalate. Furthermore, from the viewpoint of the large coercive field property, we demonstrate that a mesoscopic ε-Fe2O3 bar magnet can be used as a magnetic force microscopy probe.

Mesoscopic bar magnet based on ɛ-Fe2O3 hard ferrite

NASA Astrophysics Data System (ADS)

Ohkoshi, Shin-Ichi; Namai, Asuka; Yamaoka, Takehiro; Yoshikiyo, Marie; Imoto, Kenta; Nasu, Tomomichi; Anan, Shizuka; Umeta, Yoshikazu; Nakagawa, Kosuke; Tokoro, Hiroko

2016-06-01

Ferrite magnets have a long history. They are used in motors, magnetic fluids, drug delivery systems, etc. Herein we report a mesoscopic ferrite bar magnet based on rod-shaped ɛ-Fe2O3 with a large coercive field (>25 kOe). The ɛ-Fe2O3-based bar magnet is a single crystal with a single magnetic domain along the longitudinal direction. A wide frequency range spectroscopic study shows that the crystallographic a-axis of ɛ-Fe2O3, which corresponds to the longitudinal direction of the bar magnet, plays an important role in linear and non-linear magneto-optical transitions, phonon modes, and the magnon (Kittel mode). Due to its multiferroic property, a magnetic-responsive non-linear optical sheet is manufactured as an application using an ɛ-Fe2O3-based bar magnet, resin, and polyethylene terephthalate. Furthermore, from the viewpoint of the large coercive field property, we demonstrate that a mesoscopic ɛ-Fe2O3 bar magnet can be used as a magnetic force microscopy probe.

Variables Associated With the Subjective Experience of Coercive Measures in Psychiatric Inpatients: A Systematic Review.

PubMed

Aguilera-Serrano, Carlos; Guzman-Parra, Jose; Garcia-Sanchez, Juan A; Moreno-Küstner, Berta; Mayoral-Cleries, Fermin

2018-02-01

This systematic review presents evidence regarding factors that may influence the patient's subjective experience of an episode of mechanical restraint, seclusion, or forced administration of medication. Two authors searched CINAHL, PubMed, SCOPUS, Web of Science, and Psych-Info, considering published studies between 1 January 1992 and 1 February 2016. Based on the inclusion criteria and methodological quality, 34 studies were selected, reporting a total sample of 1,869 participants. The results showed that the provision of information, contact and interaction with staff, and adequate communication with professionals are factors that influence the subjective experience of these measures. Humane treatment, respect, and staff support are also associated with a better experience, and debriefing is an important procedure/technique to reduce the emotional impact of these measures. Likewise, the quality of the working and physical environment and some individual and treatment variables were related to the experience of these measures. There are different results in relation to the most frequently associated experiences and, despite some data that indicate positive experiences, the evidence shows such experiences to be predominantly negative and frequently with adverse consequences. It seems that patients find forced medication and seclusion to be more tolerable than mechanical restraint and combined measures. It appears that the role of the staff and the environmental conditions, which are potentially modifiable, affect the subjective experience of these measures. There was considerable heterogeneity among studies in terms of coercive measures experienced by participants and study designs.

Microstructure evolution and coercivity enhancement in Nd-Fe-B thin films diffusion-processed by R-Al alloys (R=Nd, Pr)

NASA Astrophysics Data System (ADS)

Xie, Yigao; Yang, Yang; Zhang, Tongbo; Fu, Yanqing; Jiang, Qingzheng; Ma, Shengcan; Zhong, Zhenchen; Cui, Weibin; Wang, Qiang

2018-05-01

Diffusion process by Nd-Al and Pr-Al alloys was compared and investigated in Nd-Fe-B thin films. Enhanced coercivity 2.06T and good squareness was obtained by using Pr85Al15 and Nd85Al15 alloys as diffusion sources. But the coercivity of diffusion-processed thin films by Pr70Al30 and Pr55Al45 alloys decreased to 2.04T and 1.82T. High ambient coercivity of 2.26T was achieved in diffusion-processed thin film by Nd70Al30 leading to an improved coercivity thermal stability because Nd2Fe14B grains were enveloped by Nd-rich phase as seen by transmission electron microscopy Nd-loss image. Meanwhile, microstructure-dependent parameters α and Neff were improved. However, high content of Al in diffusion-processed thin film by Nd55Al45 lead to degraded texture and coercivity.

Sexual experiences in childhood: young adults' recollections.

PubMed

Larsson, IngBeth; Svedin, Carl-Göran

2002-06-01

Childhood sexuality and children's sexual experiences have become increasingly important to study because our knowledge on the impact of sexually abusive experiences on children's developing sexuality has increased. The main aim of this paper was to study aspects of young adults' recollections of their sexual experiences before the age of 13, solitary and shared, mutual as well as coercive. Anonymous questionnaires were answered by 269 final year, senior high-school students, mean age 18.6 years; 82.9% of the students reported solitary sexual experiences and 82.5% had mutual experiences together with another child. Most of the children had their experiences together with a same-age friend. Girls had more same-sex experiences than boys did. Thirteen percent reported coercive experiences where they had been tricked, bribed, threatened, or physically forced into participation. Some children, 8.2%, had coerced another child into participation in sexual activities. The majority thought of their childhood experiences as normal. There were also 6.3% of the respondents who had had inappropriate sexual experiences with someone at least 5 years older, the majority being girls. Gender differences were evident in several respects: girls were more often coerced, they felt more guilt, and they had far less experience of masturbation, whereas boys were somewhat more active in explorative activities on their own as well as with peers. Some kind of coercive sexual experiences appears to be part of growing up for quite a few children, although in general the years before puberty seem to be years of frequent mutual sexual exploration and experimentation.

Annealing induced low coercivity, nanocrystalline Co-Fe-Si thin films exhibiting inverse cosine angular variation

NASA Astrophysics Data System (ADS)

Hysen, T.; Al-Harthi, Salim; Al-Omari, I. A.; Geetha, P.; Lisha, R.; Ramanujan, R. V.; Sakthikumar, D.; Anantharaman, M. R.

2013-09-01

Co-Fe-Si based films exhibit high magnetic moments and are highly sought after for applications like soft under layers in perpendicular recording media to magneto-electro-mechanical sensor applications. In this work the effect of annealing on structural, morphological and magnetic properties of Co-Fe-Si thin films was investigated. Compositional analysis using X-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a native oxide surface layer consisting of oxides of Co, Fe and Si on the surface. The morphology of the as deposited films shows mound like structures conforming to the Volmer-Weber growth model. Nanocrystallisation of amorphous films upon annealing was observed by glancing angle X-ray diffraction and transmission electron microscopy. The evolution of magnetic properties with annealing is explained using the Herzer model. Vibrating sample magnetometry measurements carried out at various angles from 0° to 90° to the applied magnetic field were employed to study the angular variation of coercivity. The angular variation fits the modified Kondorsky model. Interestingly, the coercivity evolution with annealing deduced from magneto-optical Kerr effect studies indicates a reverse trend compared to magetisation observed in the bulk. This can be attributed to a domain wall pinning at native oxide layer on the surface of thin films. The evolution of surface magnetic properties is correlated with morphology evolution probed using atomic force microscopy. The morphology as well as the presence of the native oxide layer dictates the surface magnetic properties and this is corroborated by the apparent difference in the bulk and surface magnetic properties.

Magnetic properties and magnetic hardening mechansim of Pt-Co-B alloys

NASA Technical Reports Server (NTRS)

Qiu, Ning; Flanagan, F.; Wittig, James E.

1994-01-01

The intrinsic coercivity is found to be maximized in the Pt42Co45B13 ternary alloy which is undercooled and rapidly solidified (quenched using a 70 m/s wheel speed after undercooling), and then annealed (800 C for 2400 min). The same alloy, processed at slower cooling rates and annealed in the same way, has a much larger scale microstructure and a much lower resulting magnetic coercivity. The microstructure which would optimize the coercitvity of this coercivity of this ternary alloy is a completely ordered L1(sub zero) Pt-Co matrix with a submicron magnetic single-domion Co-boride precipitate. The L1(sub zero) phase is highly anistropic magnetically while the Co-boride precipate is somewhat less so. Annealing treatments designed to produced single-domain Co-boride precipitates enhance the coercivity. This suggests that the refined microstructures is responsible for the high coercivities found in the rapidly solidified and annealed alloy. The magnetic domain wall thickness for a Co-boride precipitate is determined from both experimental observation and theoretical calculation in order to evaluate its influence on the coercivity of the alloy. The effects of the pinning of domain walls and the barrier to the nucleation of reverse domains on the coercivity are discussed. Both microstrucutral analysis and theoretical calculation indicate that the high coercivities in the Pt42Co45B13 alloy are due to the difficult nucleation of reverse magnetic domains.

Magnetic and structural properties of CoFe 2O 4 thin films synthesized via a sol-gel process

NASA Astrophysics Data System (ADS)

dos S. Duque, J. G.; Macêdo, M. A.; Moreno, N. O.; Lopez, J. L.; Pfanes, H.-D.

2001-05-01

Using a sol-gel process having the coconut water as a precursor of organic chain, we synthesized thin films of cobalt ferrite. The films were characterized by using a SQUID magnetometer, an X-ray diffractometer, an X-ray spectrophotometer, Mössbauer spectroscopy and atomic force microscope. Co ferrite films annealed at 500°C for 2 h show grain sizes between 10 and 20 nm, grown as single-phase spinel structure and exhibit high coercivity and a moderate saturation magnetization (above 30 kOe).

[Associations of short-term evaluation assessments and patient characteristics with the use of coercive measures].

PubMed

Vermeulen, R C; Nijman, H L I; van de Sande, R; Lohuis-Heesink, H A G M

Dutch mental health care institutes are currently making a tremendous effort to reduce the number of coercive measures they impose, such as seclusion. Despite this effort, a group of patients are still being subjected to enforced medication or seclusion. To obtain more knowledge about which patient characteristics are associated with coercive measures and thereby to identify signs that could be acted upon at an earlier stage to prevent deterioration of the patient's condition and reduce the need for coercive measures. We performed a prospective, naturalistic three-month study involving patients in two acute psychiatric admission wards. To collect the data we required, we used two short-term risk-assessment instruments: the Brøset Violence Checklist (BVC) and the Kennedy Axis V (KA-V). By means of statistical analyses we investigated which patient characteristics were associated with the use of coercive measures. Of the 179 patients, 52 patients (29%) were subjected to a coercive measure during the admission procedure. The following patient characteristics were found to be associated with coercive measures: a bipolar disorder, involuntarily admission, display of physical violence just before admission, scores on the BVC and the KA-V items assessing 'social skills' and 'violence'. The two BVC items 'attacks on objects' and 'display of physical violence just before admission' were the ones most strongly associated with seclusion. Although the sensitivity of the regression model was modest, the associated patient characteristics, combined with the two short-term risk assessment scores, may be helpful for identifying at an early stage those patients who run a high risk of being subjected to coercive measures.

Structure and magnetic properties of low-temperature phase Mn-Bi nanosheets with ultra-high coercivity and significant anisotropy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Rongming, E-mail: rmliu@iphy.ac.cn, E-mail: shenbg@iphy.ac.cn; Zhang, Ming; Niu, E

2014-05-07

The microstructure, crystal structure, and magnetic properties of low-temperature phase (LTP) Mn-Bi nanosheets, prepared by surfactant assistant high-energy ball milling (SA-HEBM) with oleylamine and oleic acid as the surfactant, were examined with scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer, respectively. Effect of ball-milling time on the coercivity of LTP Mn-Bi nanosheets was systematically investigated. Results show that the high energy ball milling time from tens of minutes to several hours results in the coercivity increase of Mn-Bi powders and peak values of 14.3 kOe around 10 h. LTP Mn-Bi nanosheets are characterized by an average thickness of tensmore » of nanometers, an average diameter of ∼1.5 μm, and possess a relatively large aspect ratio, an ultra-high room temperature coercivity of 22.3 kOe, a significant geometrical and magnetic anisotropy, and a strong (00l) crystal texture. Magnetization and demagnetization behaviors reveal that wall pinning is the dominant coercivity mechanism in these LTP Mn-Bi nanosheets. The ultrafine grain refinement introduced by the SA-HEBM process contribute to the ultra-high coercivity of LTP Mn-Bi nanosheets and a large number of defects put a powerful pinning effect on the magnetic domain movement, simultaneously. Further magnetic measurement at 437 K shows that a high coercivity of 17.8 kOe and a strong positive temperature coefficient of coercivity existed in the bonded permanent magnet made by LTP Mn-Bi nanosheets.« less

Coercivity enhancement of Dy-coated Nd-Fe-B flakes by crystallization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukunaga, H.; Sugimoto, Y.; Nakano, M.

2011-04-01

The coercivity of isotropic Dy-coated Nd-Fe-B flakes was enhanced by crystallization and simultaneous diffusion of Dy from their surfaces. Amorphous Dy-coated Nd-Fe-B flakes were crystallized by heating them to 923 K 2over a 2 min period followed by rapid cooling. During crystallization, the Dy on the surface diffused into the flakes. This low-temperature rapid annealing produced flakes with fine grains and the Dy diffusion enhanced their coercivity. The coercivity after crystallization increased with increasing Dy layer thickness, although the remanence decreased when the layer thickness exceeded 3 {mu}m. Thick coatings of over 6 {mu}m resulted in the formation of DyFe{submore » 2}, which degraded the magnetic properties of the crystallized flakes. Flakes with a 3-{mu}m-thick coating exhibited excellent magnetic properties after annealing: They had a coercivity of 1880 kA/m and a remanence of 78 emu/g. This coercivity is approximately 500 kA/m higher than that of uncoated flakes, whereas the remanence is comparable to that of uncoated flakes.« less

Relationships Between Shame, Restrictiveness, Authoritativeness, and Coercive Control in Men Mandated to a Domestic Violence Offenders Program.

PubMed

Kaplenko, Hannah; Loveland, Jennifer E; Raghavan, Chitra

2018-04-01

Coercive control, a key element of intimate partner violence (IPV), is defined as an abuse dynamic that intends to strip the target of autonomy and liberty. While coercive control is gaining popularity in the research world, little is known about its correlates and causes. This study sought to examine how shame and men's need for dominance, measured by two trait indexes of dominance, restrictiveness and the need for authority, influence coercive control. The present study used a diverse sample of men (n = 134) who were mandated to attend a domestic violence offenders program. Findings suggest that shame plays a role in the commission of coercively controlling behavior both directly and partially through its influence on authority but not through restrictiveness. Implications for understanding IPV in a domestic violence offenders program are discussed.

[Coercive procedures in forensic psychiatry : Current treatment practice in forensic psychiatric hospitals from a medical ethics perspective].

PubMed

Jakovljević, A-K; Wiesemann, C

2016-07-01

In 2011 the legal foundations of coercive treatment in German forensic psychiatric clinics were declared to be unconstitutional. In the present study we analyzed the frequency of coercive procedures in forensic psychiatric hospitals before and after 2011, the consequences for medical care as well as the ethical assessments by attending chief physicians. By a questionnaire-based survey of views of attending chief physicians in forensic psychiatric clinics in 2013, data on the current state of patient care were collected and analyzed from an ethical perspective. These were compared with treatment data from a large forensic psychiatric clinic collected over the period 2007-2013. Even after 2011 coercive forms of treatment were applied in forensic psychiatric hospitals. In practice, there is a high degree of legal uncertainty regarding the limits of coercive treatment. Of all patients treated in forensic psychiatric clinics in 2012, on average 13 % had been in isolation at least once, approximately 3 % had been treated under fixation at least once and 2.2 % had been subjected to coercive medical treatment at least once. From an ethical perspective an open debate about the practice of coercive treatment is urgently required. Legal regulations, ethical guidelines and treatment standards have to be developed for the special situation of patient care in forensic psychiatric hospitals.

Parental Perceptions of the Use of Coercive Measures on Children with Developmental Disabilities

ERIC Educational Resources Information Center

Saloviita, Timo; Pirttimaa, Raija; Kontu, Elina

2016-01-01

Background: Children with developmental disabilities who exhibit challenging behaviour are potentially subject to the use of coercive interventions. The aim of the study was to investigate the prevalence of the use of coercive measures by authorities, according to parents' reports. Materials and Methods: A postal survey was distributed, as a total…

Computational alloy design of (Co1-xNix)88Zr7B4Cu1 nanocomposite soft magnets

NASA Astrophysics Data System (ADS)

Dong, B.; Healy, J.; Lan, S.; Daniil, M.; Willard, M. A.

2018-05-01

The dependence of coercivity on composition is an important factor for establishing optimized soft magnetic properties. In this study, we have used the random anisotropy and coherent rotation models to estimate the variation of coercivity with composition in (Co1-xNix)88Zr7B4Cu1 nanocomposite alloys. Our calculations that the magnetoelastic anisotropy contribution to coercivity dominates for Ni rich compositions (x > 0.5). A small range of compositions (0.65 < x < 0.75) is predicted to result in low values of coercivity (<10 A/m). To validate this prediction, (Co1-xNix)88Zr7B4Cu1 nanocomposites in this range were prepared by melt spinning followed by 3600 s isothermal annealing at the primary crystallization peak temperature (˜673 K). Hysteresis loops were measured using vibrating sample magnetometry at room temperature and saturation magnetostriction was measured using a strain gage based magnetostrictometer. Moderately small coercivities (30-40 A/m) and magnetostrictions (3-4 ppm) were measured at for samples with 0.685 < x < 0.725. Our measured coercivity had a minimum value of 32 A/m at x = 0.725, a shift in composition of about 5 at% in the direction of higher Ni content and without the anticipated low value of coercivity. Several reasons for the inaccuracy of this approach are described, including: ignored contributions from amorphous phase (especially in magnetoealstic anisotropy), composition segregation during crystallization leading to unpredictable compositional shifts in prediction, and the general observation that the predictability of minimum coercivity from minimal combined anisotropies has unexplained deviation even in far less complicated materials.

Random-anisotropy model: Monotonic dependence of the coercive field on D/J

NASA Astrophysics Data System (ADS)

Saslow, W. M.; Koon, N. C.

1994-02-01

We present the results of a numerical study of the zero-temperature remanence and coercivity for the random anisotropy model (RAM), showing that, contrary to early calculations for this model, the coercive field increases monotonically with increases in the strength D of the random anisotropy relative to the strength J at the exchange field. Local-field adjustments with and without spin flips are considered. Convergence is difficult to obtain for small values of the anisotropy, suggesting that this is the likely source of the nonmonotonic behavior found in earlier studies. For both large and small anisotropy, each spin undergoes about one flip per hysteresis cycle, and about half of the spin flips occur in the vicinity of the coercive field. When only non-spin-flip adjustments are considered, at large anisotropy the coercivity is proportional to the anisotropy. At small anisotropy, the rate of convergence is comparable to that when spin flips are included.

Perceptions of sexual coercion: learning from young people in Ibadan, Nigeria.

PubMed

Ajuwon, A J; Akin-Jimoh, I; Olley, B O; Akintola, O

2001-05-01

This study explored the problem of sexual coercion from the perspectives of 77 young people aged 14-21 in Ibadan, Nigeria, the behaviours they perceive to be sexually coercive and the contexts in which these occur through four narrative workshops. Participants were drawn from two secondary schools and 15 apprentice workshops. All four groups identified similar coercive behaviours and developed narratives of the events that typically lead up to them. Behaviours included rape, unwanted touching, incest, assault, verbal abuse, threats, unwanted kissing; forced exposure to pornographic films, use of drugs for sedation and traditional charms for seduction, and insistence on abortion if unwanted pregnancy occurs. Men were typically the perpetrators and young women the victims. Perpetrators included acquaintances, boyfriends, neighbours, parents and relatives. All the narratives revealed the inability of young people to communicate effectively with each other and resolve differences. The results suggest the need for life-skills training that facilitates communication, seeks to redress gender power imbalances, teaches alternatives to coercion as a means of resolving conflict over sexual relations and respect for sexual and reproductive rights, and provides victims with information on appropriate services, support and referral.

Thermal treatment induced modification of structural, surface and bulk magnetic properties of Fe61.5Co5Ni8Si13.5B9Nb3 metallic glass

NASA Astrophysics Data System (ADS)

Shah, M.; Satalkar, M.; Kane, S. N.; Ghodke, N. L.; Sinha, A. K.; Varga, L. K.; Teixeira, J. M.; Araujo, J. P.

2018-05-01

Effect of thermal annealing induced modification of structural, surface and bulk magnetic properties of Fe61.5Co5Ni8Si13.5B9Nb3 alloy is presented. The changes in properties were observed using synchrotron x-ray diffraction technique (SXRD), atomic force microscopy (AFM), magneto-optical kerr effect (MOKE) and bulk magnetic measurements. Significant variations on the both side of surface occur for the annealing temperature upto 500 °C promotes the surface crystallization. Surface roughness appears due to presence of nanocrystallization plays an important role in determining magnetic properties. Observed lower value of bulk coercivity Hc of 6.2 A/m annealed temperature at 450 °C/1 h ascribed to reduction of disorder as compared to the surface (both shiny and wheel side observed by MOKE measurement) whereas improvement of bulk saturation magnetization with annealing temperature indicates first near neighbor shell of Fe atoms are surrounded by Fe atoms. Evolution of coercivity of surface and bulk with annealing temperature has been presented in conjunction with the structural observations.

Effect of sexual coercion proclivity, insult and fantasy on emotional reactivity and appeal of sexual aggression.

PubMed

Thomas, Lindsey A; Gorzalka, Boris B

2012-08-01

Fifty-nine heterosexual university males were assessed for Sexual Coercion Proclivity (SCP) and randomly assigned to one of three conditions: Insult/nonsexually coercive fantasy material; no insult/sexually coercive fantasy material; or, insult/sexually coercive fantasy material. Although not differing in terms of anger or anxiety, the high SCP became more frustrated than the low group, particularly when exposed to both insult and sexually coercive (SC) fantasy material. Changes in negative affect predicted anticipated likelihood of engaging in SC among the low SCP group and anticipated enjoyment of SC in the high SCP group. Acculturation accounted for differences observed between Caucasian and Chinese men.

Anomalous behaviour of magnetic coercivity in graphene oxide and reduced graphene oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagani, K.; Bhattacharya, A.; Kaur, J.

In this report, we present the temperature dependence of the magnetic coercivity of graphene oxide (GO) and reduced graphene oxide (RGO). We observe an anomalous decrease in coercivity of GO and RGO with decreasing temperature. The observation could be understood by invoking the inherent presence of wrinkles on graphene oxide due to presence of oxygen containing groups. Scanning electron microscopic image reveals high wrinkles in GO than RGO. We observe higher coercivity in RGO than in GO. At room temperature, we observe antiferromagnetic and ferromagnetic behaviours in GO and RGO, respectively. Whereas, at low temperatures (below T = 60–70 K), both materials showmore » paramagnetic behaviour.« less

High temperature coercive field behavior of Fe-Zr powder

NASA Astrophysics Data System (ADS)

Mishra, Debabrata; Perumal, A.; Srinivasan, A.

2009-04-01

We report the investigation of high temperature coercive field behavior of Fe80Zr20 nanocrystalline alloy powder having two-phase microstructure prepared by mechanical alloying process. Thermomagnetization measurement shows the presence of two different magnetic phase transitions corresponding to the amorphous matrix and nonequilibrium Fe(Zr) solid solution. Temperature dependent coercivity exhibits a sharp increase in its value close to the Curie temperature of the amorphous matrix. This feature is attributed to the loss of intergranular ferromagnetic exchange coupling between the nanocrystallites due to the paramagnetic nature of the amorphous matrix. The temperature dependent coercive field behavior is ascribed to the variations in both the effective anisotropy and the exchange stiffness constant with temperature.

Structure, coercive control, and autonomy promotion: A comparison of fathers' and mothers' food parenting strategies.

PubMed

Pratt, Mercedes; Hoffmann, Debra; Taylor, Maija; Musher-Eizenman, Dara

2017-05-01

This study explored differences in mothers' and fathers' food parenting strategies, specifically coercive control, structure, and autonomy promotion, and whether parenting style and parental responsibility for food parenting related to the use of these strategies. Parents of children aged 2.5-7.5 years ( N = 497) reported about their parenting practices and food parenting strategies. Parenting style accounted for the majority of the variance in food parenting. Fathers were more authoritarian than mothers. Authoritarian and permissive parenting practices were related to more coercive strategies. Mothers reported more food parenting responsibility. Responsibility was related to less coercive practices and more autonomy promotion and structure.

A preliminary report on the magnetic measurements of samples 72275 and 72255. [direction and magnitude of remanent magnetization

NASA Technical Reports Server (NTRS)

Banerjee, S. K.

1974-01-01

The direction and magnitude of natural remanent magnetization of five approximately 3-g subsamples of 72275 and 72255 and the high field saturation magnetization, coercive force, and isothermal remanent magnetization of 100-mg chip from each of these samples, were studied. Given an understanding of the magnetization processes, group 1 experiments provide information about the absolute direction of the ancient magnetizing field and a qualitative estimate of its size (paleointensity). The group 2 experiments yield a quantitative estimate of the iron content and a qualitative ideal of the grain sizes.

Coercivity enhancement of sintered Nd-Fe-B magnets by chemical bath deposition

NASA Astrophysics Data System (ADS)

Zhang, Qiushuang; Guo, Shuai; Yang, Xiao; Zeng, Jiling; Cao, Xuejing; Chen, Renjie; Yan, Aru

2018-05-01

The chemical bath deposition (CBD) method is used to diffuse the heavy rare earth element in order to obtain the high coercivity magnets with low heavy rare earth element. The jet mill powders are soaked in the alcohol suspension of Dy(CH3CHOHCH3)3 (Dy-ipa) so that Nd2Fe14B powder particles are surrounded by Dy-ipa homogeneously. By adding 1.0 wt. % Dy, the coercivity of magnet is increased from 14.47 kOe to 17.55 kOe with slight reduction of remanence after grain boundary diffusion (GBD) in the sintering and annealing processes. The temperature coefficient of coercivity optimizes from -0.629 %/°C to -0.605 %/°C as well as that of remanence improves from -0.108 %/°C to -0.100 %/°C. The CBD method is helpful for thermal stability and alignment either. The relation between the microstructure and the coercivity has been studied systematically.

Investigation of coercivity for electroplated Fe-Ni thick films

NASA Astrophysics Data System (ADS)

Yanai, T.; Eguchi, K.; Koda, K.; Kaji, J.; Aramaki, H.; Takashima, K.; Nakano, M.; Fukunaga, H.

2018-05-01

We have already reported Fe-Ni firms with good soft magnetic properties prepared by using an electroplating method. In our previous studies, we prepared the Fe-Ni films from citric-acid-based baths (CA-baths) and ammonium-chloride-based ones (AC-baths), and confirmed that the coercivity for the AC-baths was lower than that for the CA-baths. In the present study, we investigated reasons for the lower coercivity for the AC-baths to further improve the soft magnetic properties. From an observation of magnetic domains of the Fe22Ni78 films, we found that Fe22Ni78 film for AC-bath had a magnetic anisotropy in the width direction, and also found that the coercivity in the width direction was lower than the longitudinal one for the AC-bath. As an annealing for a stress relaxation in the films reduced the difference in the coercivity, we considered that the anisotropy is attributed to the magneto-elastic effect.

Operations Odyssey Dawn and Unified Protector: A Coercive Failure?

DTIC Science & Technology

2012-12-06

Coercive Air Power: A Primer for Military Strategists,” Air Power Journal 2, no. 1 (Spring 2007 ): 160. Mueller also argues that compellence and...faced defeat. Coalition Narrative/Strategic Goals As the resistance against the Libyan government stammered , the United States sought to increase...Mueller, Karl. “The Essence of Coercive Air Power: A Primer for Military Strategists,” Air Power Journal 2, no. 1 (Spring 2007 ): 159-174. NATO. Fact

Coercivity enhancement of anisotropic Dy-free Nd-Fe-B powders by conventional HDDR process

NASA Astrophysics Data System (ADS)

Morimoto, K.; Katayama, N.; Akamine, H.; Itakura, M.

2012-11-01

Coercivity enhancement of Dy-free Nd-Fe-Co-B-Ga-Zr powders was studied using the conventional hydrogenation-decomposition-desorption-recombination (HDDR) process. It was found that the addition of Al together with the proper Nd content and the slow hydrogen desorption of the HDDR treatment can induce high coercivity in the powder. For example, the 14.0 at% Nd-2.0 at% Al powder exhibits HcJ of 1560 kA/m, Br of 1.22 T, and (BH)max of 257 kJ/m3. The high coercivity inducement of the powder is thought to be attributed to the formation of Nd-rich phase, which continuously surrounds fine Nd2Fe14B grains.

Switching of magnetic easy-axis using crystal orientation for large perpendicular coercivity in CoFe2O4 thin film

PubMed Central

Shirsath, Sagar E.; Liu, Xiaoxi; Yasukawa, Yukiko; Li, Sean; Morisako, Akimitsu

2016-01-01

Perpendicular magnetization and precise control over the magnetic easy axis in magnetic thin film is necessary for a variety of applications, particularly in magnetic recording media. A strong (111) orientation is successfully achieved in the CoFe2O4 (CFO) thin film at relatively low substrate temperature of 100 °C, whereas the (311)-preferred randomly oriented CFO is prepared at room temperature by the DC magnetron sputtering technique. The oxygen-deficient porous CFO film after post-annealing gives rise to compressive strain perpendicular to the film surface, which induces large perpendicular coercivity. We observe the coercivity of 11.3 kOe in the 40-nm CFO thin film, which is the highest perpendicular coercivity ever achieved on an amorphous SiO2/Si substrate. The present approach can guide the systematic tuning of the magnetic easy axis and coercivity in the desired direction with respect to crystal orientation in the nanoscale regime. Importantly, this can be achieved on virtually any type of substrate. PMID:27435010

Angular dependence of coercivity in isotropically aligned Nd-Fe-B sintered magnets

NASA Astrophysics Data System (ADS)

Matsuura, Yutaka; Nakamura, Tetsuya; Sumitani, Kazushi; Kajiwara, Kentaro; Tamura, Ryuji; Osamura, Kozo

2018-05-01

In order to understand the coercivity mechanism in Nd-Fe-B sintered magnets, the angular dependence of the coercivity of an isotropically aligned Nd15Co1.0B6Febal. sintered magnet was investigated through magnetization measurements using a vibrating sample magnetometer. These results are compared with the angular dependence calculated under the assumption that the magnetization reversal of each grain follows the Kondorskii law or, in other words, the 1/cos θ law for isotropic alignment distributions. The calculated angular dependence of the coercivity agrees very well with the experiment for magnetic fields applied between angles of 0 and 60°, and it is expected that the magnetization reversal occurs in each grain individually followed the 1/cos θ law. In contrast, this agreement between calculation and experiment is not found for anisotropic Nd-Fe-B samples. This implies that the coercivity of the aligned magnets depends upon the de-pinning of the domain walls from pinning sites. When the de-pinning occurs, it is expected that the domain walls are displaced through several grains at once.

Substrate bias effects on composition and coercivity of CoCrTa/Cr thin films on canasite and glass

NASA Astrophysics Data System (ADS)

Deng, Y.; Lambeth, D. N.; Sui, X.; Lee, L.-L.; Laughlin, D. E.

1993-05-01

CoCrTa/Cr thin films were prepared by rf diode sputtering onto canasite and glass substrates at various bias voltages from two targets of different compositions (Co82.8Cr14.6Ta2.6 and Co86Cr12Ta2). While Auger depth profile analysis indicates that there is some broadening at the CoCrTa-Cr interface, x-ray fluorescence spectroscopy reveals that changes in alloy composition due to the resputtering processes are even more prominent. For both targets, as the substrate bias increases the Co content in the films declines, and the magnetization decreases. The maximum film coercivity appears to correlate to the final film composition. By investigating the results from both targets, it is concluded that the coercivity reaches a maximum when the film composition is in the neighborhood of Co84Cr13Ta3. Thus, to optimize the coercivity different bias voltages are required for each target. Excessive substrate bias, however, leads to films with low magnetization and coercivity.

Authorities' Coercive and Legitimate Power: The Impact on Cognitions Underlying Cooperation

PubMed Central

Hofmann, Eva; Hartl, Barbara; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

2017-01-01

The execution of coercive and legitimate power by an authority assures cooperation and prohibits free-riding. While coercive power can be comprised of severe punishment and strict monitoring, legitimate power covers expert, and informative procedures. The perception of these powers wielded by authorities stimulates specific cognitions: trust, relational climates, and motives. With four experiments, the single and combined impact of coercive and legitimate power on these processes and on intended cooperation of n1 = 120, n2 = 130, n3 = 368, and n4 = 102 student participants is investigated within two exemplary contexts (tax contributions, insurance claims). Findings reveal that coercive power increases an antagonistic climate and enforced compliance, whereas legitimate power increases reason-based trust, a service climate, and voluntary cooperation. Unexpectedly, legitimate power is additionally having a negative effect on an antagonistic climate and a positive effect on enforced compliance; these findings lead to a modification of theoretical assumptions. However, solely reason-based trust, but not climate perceptions and motives, mediates the relationship between power and intended cooperation. Implications for theory and practice are discussed. PMID:28149286

Predicting sexual coercion in early adulthood: The transaction among maltreatment, gang affiliation, and adolescent socialization of coercive relationship norms.

PubMed

Ha, Thao; Kim, Hanjoe; Christopher, Caroline; Caruthers, Allison; Dishion, Thomas J

2016-08-01

This study tested a transactional hypothesis predicting early adult sexual coercion from family maltreatment, early adolescent gang affiliation, and socialization of adolescent friendships that support coercive relationship norms. The longitudinal study of a community sample of 998 11-year-olds was intensively assessed in early and middle adolescence and followed to 23-24 years of age. At age 16-17 youth were videotaped with a friend, and their interactions were coded for coercive relationship talk. Structural equation modeling revealed that maltreatment predicted gang affiliation during early adolescence. Both maltreatment and gang affiliation strongly predicted adolescent sexual promiscuity and coercive relationship norms with friends at age 16-17 years. Adolescent sexual promiscuity, however, did not predict sexual coercion in early adulthood. In contrast, higher levels of observed coercive relationship talk with a friend predicted sexual coercion in early adulthood for both males and females. These findings suggest that peers have a socialization function in the development of norms prognostic of sexual coercion, and the need to consider peers in the promotion of healthy relationships.

Material deprivation and unemployment affect coercive sex among young people in the urban slums of Blantyre, Malawi: A multi-level approach.

PubMed

Kamndaya, Mphatso; Kazembe, Lawrence N; Vearey, Jo; Kabiru, Caroline W; Thomas, Liz

2015-05-01

We explore relations among material deprivation (measured by insufficient housing, food insecurity and poor healthcare access), socio-economic status (employment, income and education) and coercive sex. A binary logistic multi-level model is used in the estimation of data from a survey of 1071 young people aged 18-23 years, undertaken between June and July 2013, in the urban slums of Blantyre, Malawi. For young men, unemployment was associated with coercive sex (odds ratio [OR]=1.77, 95% confidence interval [CI]: 1.09-3.21) while material deprivation (OR=1.34, 95% CI: 0.75-2.39) was not. Young women in materially deprived households were more likely to report coercive sex (OR=1.37, 95% CI: 1.07-2.22) than in non-materially deprived households. Analysis of local indicators of deprivation is critical to inform the development of effective strategies to reduce coercive sex in urban slums in Malawi. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of an annealing on magnetic properties of Fe-Ni films electroplated in citric-acid-based plating baths

NASA Astrophysics Data System (ADS)

Yanai, T.; Koda, K.; Eguchi, K.; Morimura, T.; Takashima, K.; Nakano, M.; Fukunaga, H.

2018-04-01

We have already reported Fe-Ni films with good soft magnetic properties prepared by using an electroplating method. In the present study, we employed an annealing for further improvement in soft magnetic properties of the electroplated Fe-Ni films. The annealing reduces the coercivity of the films, and the reduction rate of the coercivity depended on the Cl- ion concentration in the bath. The Fe22Ni78 films prepared in the plating bath with high Cl- ion concentration showed large reduction rate of the coercivity, and we found that the annealing is more effective for high Cl- ion concentration bath since much lower coercivity value can be obtained compared with that for low Cl- ion concentration one.

5 CFR 950.108 - Preventing coercive activity.

Code of Federal Regulations, 2011 CFR

2011-01-01

... PRIVATE VOLUNTARY ORGANIZATIONS General Provisions § 950.108 Preventing coercive activity. True voluntary... Section 950.108 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... the supervisor's unit or organization. ...

5 CFR 950.108 - Preventing coercive activity.

Code of Federal Regulations, 2012 CFR

2012-01-01

... PRIVATE VOLUNTARY ORGANIZATIONS General Provisions § 950.108 Preventing coercive activity. True voluntary... Section 950.108 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... the supervisor's unit or organization. ...

5 CFR 950.108 - Preventing coercive activity.

Code of Federal Regulations, 2013 CFR

2013-01-01

... PRIVATE VOLUNTARY ORGANIZATIONS General Provisions § 950.108 Preventing coercive activity. True voluntary... Section 950.108 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... the supervisor's unit or organization. ...

5 CFR 950.108 - Preventing coercive activity.

Code of Federal Regulations, 2014 CFR

2014-01-01

... PRIVATE VOLUNTARY ORGANIZATIONS General Provisions § 950.108 Preventing coercive activity. True voluntary... Section 950.108 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... the supervisor's unit or organization. ...

Surface analysis of Fe-Co-Mo electrolytic coatings

NASA Astrophysics Data System (ADS)

Yar-Mukhamedova, G. Sh; Sakhnenko, N. D.; Ved', M. V.; Yermolenko, I. Yu; Zyubanova, S. I.

2017-06-01

Coatings Fe-Co-Mo with a composition of 47 at.% iron, 28 at.% Cobalt and 25 at.% Molybdenum were deposited from citrate electrolyte using pulse electrolysis mode. Scanning electron and atomic force microscopy have established the surface morphology and topography. It was identified the parts with a globular structure which have an average size of 0.2-0.5μm and singly located sharp grains. Within the same scan area sites with developed surface were detected the topography of which is identical to the crystal structure of cobalt with the crystallites size of 0.2-1.75μm. The parameters Ra and Rq for parts with different morphology as well as average characteristics of coatings demonstrated the low roughness of the surface. It is found that the coercive force of Fe-Co-Mo films is 7-10 Oe, which allow us to classify the Fe-Co-Mo coatings as soft magnetic materials.

Antidot patterned single and bilayer thin films based on ferrimagnetic Tb-Co alloy with perpendicular magnetic anisotropy

NASA Astrophysics Data System (ADS)

Kulesh, N. A.; Vázquez, M.; Lepalovskij, V. N.; Vas'kovskiy, V. O.

2018-02-01

Hysteresis properties and magnetization reversal in TbCo(30 nm) and FeNi(10 nm)/TbCo(30 nm) films with nanoscale antidot lattices are investigated to test the effect of nanoholes on the perpendicular anisotropy in the TbCo layer and the induced exchange bias in the FeNi layer. The antidots are introduced by depositing the films on top of hexagonally ordered porous anodic alumina substrates with pore diameter and interpore distance fixed to 75 nm and 105 nm, respectively. The analysis of combined vibrating sample magnetometry, Kerr microscopy and magnetic force microscopy imaging measurements has allowed us to link macroscopic and local magnetization reversal processes. For magnetically hard TbCo films, we demonstrate the tunability of magnetic anisotropy and coercive field (i.e., it increases from 0.2 T for the continuous film to 0.5 T for the antidot film). For the antidot FeNi/TbCo film, magnetization of FeNi is confirmed to be in plane. Although an exchange bias has been locally detected in the FeNi layer, the integrated hysteresis loop has increased coercivity and zero shift along the field axis due to the significantly decreased magnetic anisotropy of TbCo layer.

Characterization facility for magneto-optic media and systems

NASA Technical Reports Server (NTRS)

Mansuripur, M.; Fu, H.; Gadetsky, S.; Sugaya, S.; Wu, T. H.; Zambuto, J.; Gerber, R.; Goodman, T.; Erwin, J. K.

1993-01-01

Objectives of this research are: (1) to measure the hysteresis loop, Kerr rotation angle, anisotropy energy profile, Hall voltage, and magnetoresistance of thin-film magneto-optic media using our loop-tracer; (2) measure the wavelength-dependence of the Kerr rotation angle, Theta(sub k), and ellipticity, epsilon(sub k), for thin-film media using our magneto-optic Kerr spectrometer (MOKS); (3) measure the dielectric tensor of thin-film and multilayer samples using our variable-angle magneto-optic ellipsometer (VAMOE); (4) measure the hysteresis loop, coercivity, remanent magnetization, saturation magnetization, and anisotropy energy constant for thin film magnetic media using vibrating sample magnetometry; (5) observe small magnetic domains and investigate their interaction with defects using magnetic force microscopy; (6) perform static read/write/erase experiments on thin-film magneto-optic media using our static test station; (7) integrate the existing models of magnetization, magneto-optic effects, coercivity, and anisotropy in an interactive and user-friendly environment, and analyze the characterization data obtained in the various experiments, using this modeling package; (8) measure focusing- and tracking-error signals on a static testbed, determine the 'feedthrough' for various focusing schemes, investigate the effects of polarization and birefringence, and compare the results with diffraction-based calculations; and (9) measure the birefringence of optical disk substrates using two variable angle ellipsometers.

Female reproductive strategies in orangutans, evidence for female choice and counterstrategies to infanticide in a species with frequent sexual coercion

PubMed Central

Knott, Cheryl Denise; Emery Thompson, Melissa; Stumpf, Rebecca M.; McIntyre, Matthew H.

2010-01-01

Intersexual conflicts over mating can engender antagonistic coevolution of strategies, such as coercion by males and selective resistance by females. Orangutans are exceptional among mammals for their high levels of forced copulation. This has typically been viewed as an alternative mating tactic used by the competitively disadvantaged unflanged male morph, with little understanding of how female strategies may have shaped and responded to this behaviour. Here, we show that male morph is not by itself a good predictor of mating dynamics in wild Bornean orangutans but that female conception risk mediated the occurrence and quality of male–female interactions. Near ovulation, females mated cooperatively only with prime flanged males who they encountered at higher rates. When conception risk was low, willingness to associate and mate with non-prime males increased. Our results support the hypothesis that, together with concealed ovulation, facultative association is a mechanism of female choice in a species in which females can rarely avoid coercive mating attempts. Female resistance, which reduced copulation time, may provide an additional mechanism for mate selection. However, coercive factors were also important as prime males were frequently aggressive to females and females used mating strategies consistent with infanticide avoidance. PMID:19812079

Influence of magnet eddy current on magnetization characteristics of variable flux memory machine

NASA Astrophysics Data System (ADS)

Yang, Hui; Lin, Heyun; Zhu, Z. Q.; Lyu, Shukang

2018-05-01

In this paper, the magnet eddy current characteristics of a newly developed variable flux memory machine (VFMM) is investigated. Firstly, the machine structure, non-linear hysteresis characteristics and eddy current modeling of low coercive force magnet are described, respectively. Besides, the PM eddy current behaviors when applying the demagnetizing current pulses are unveiled and investigated. The mismatch of the required demagnetization currents between the cases with or without considering the magnet eddy current is identified. In addition, the influences of the magnet eddy current on the demagnetization effect of VFMM are analyzed. Finally, a prototype is manufactured and tested to verify the theoretical analyses.

Nano-embossing technology on ferroelectric thin film Pb(Zr0.3,Ti0.7)O3 for multi-bit storage application

PubMed Central

2011-01-01

In this work, we apply nano-embossing technique to form a stagger structure in ferroelectric lead zirconate titanate [Pb(Zr0.3, Ti0.7)O3 (PZT)] films and investigate the ferroelectric and electrical characterizations of the embossed and un-embossed regions, respectively, of the same films by using piezoresponse force microscopy (PFM) and Radiant Technologies Precision Material Analyzer. Attributed to the different layer thickness of the patterned ferroelectric thin film, two distinctive coercive voltages have been obtained, thereby, allowing for a single ferroelectric memory cell to contain more than one bit of data. PMID:21794156

A re-appraisal of the proposed rapid Matuyama-Brunhes geomagnetic reversal in the Sulmona Basin, Italy

NASA Astrophysics Data System (ADS)

Evans, M. E.; Muxworthy, A. R.

2018-06-01

An extremely sharp magnetic reversal observed in lacustrine sediments in central Italy has been interpreted as a record of the Matuyama-Brunhes geomagnetic polarity reversal that may represent less than a decade. Here, we report new results from the same Sulmona Basin outcrops that question this interpretation. In particular, we find evidence of reversed (Matuyama) directions well above the proposed Matuyama-Brunhes Boundary (MBB). Coercivity spectra of anhysteretic remanent magnetization imply a three-component magnetic mineralogy: low-, intermediate- and high-coercivity. The low-coercivity component is found in all but one of the samples and carries a strong modern overprint seen throughout the section. The high-coercivity component is dominated by volcanic material which is prone to remagnetization. Since it is much more magnetic than the surrounding lacustrine sediments, it may influence the remanence signal even when present at very low concentrations. The intermediate-coercivity component is the main carrier of any true primary remanence, but whether or not this can be isolated depends on the blocking temperature and coercivity spectra of individual samples and on the demagnetization method used. The complexity of the magnetization, the reversed zones above the proposed MBB and the normal zones that Sagnotti and colleagues found below it lead to the conclusion that this section does not carry a reliable high-resolution record of the geomagnetic field. Thus, we feel that inferences about the stratigraphic position and duration of the MBB are premature.

First order reversal curve study of the dipolar interaction in Ni three-dimensional antidot arrays

NASA Astrophysics Data System (ADS)

Li, Bingqing; Chai, Xuzhao; Moeendarbari, Sina; Hao, Yaowu; Gilbert, Dustin A.; Liu, Kai; Zhang, Di; Feng, Gang; Han, Ping; Cheng, X. M.

2014-03-01

Three-dimensional antidot arrays (3DAAs) have attracted considerable attention due to potential applications in sensors, energy storage and transducers. Magnetic 3DAAs also provide an ideal system for studying the effect of dimensionality and morphology on magnetic properties. We report study of dipolar interactions in Ni 3DAAs using the first-order reversal curve (FORC) method. Ordered Ni 3DAAs were fabricated by electrochemical deposition into colloidal crystal templates of self-assembled polystyrene spheres. The samples have the same pore size of about 500 nm but different thicknesses, ranging from 0.3 μm to 1.2 μm, confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). FORCs of the samples with thicknesses of 0.3 μm, 0.8 μm, and 1.2 μm were measured by a vibrating sample magnetometer. The FORC diagram analysis reveals a demagnetizing magnetic dipolar interaction, and a decrease in the interaction strength with the increasing sample thickness, evidenced by a decrease in the spread of the irreversible peak in the bias distribution, as well as a decrease in the tilting of the FORC distribution from the local coercivity axis. Work at BMC and UCD is supported by NSF DMR-1207085 and DMR-1008791, respectively.

Coercivity Recovery Effect of Sm-Fe-Cu-Al Alloy on Sm2Fe17N3 Magnet

NASA Astrophysics Data System (ADS)

Otogawa, Kohei; Asahi, Toru; Jinno, Miho; Yamaguchi, Wataru; Takagi, Kenta; Kwon, Hansang

2018-03-01

The potential of a Sm-Fe-Cu-Al binder for improvement of the magnetic properties of Sm2Fe17N3 was examined. Transmission electron microscope (TEM) observation of a Sm-Fe-Cu-Al alloy-bonded Sm2Fe17N3 magnet which showed high coercivity revealed that the Sm-Fe-Cu-Al alloy had an effect of removing the surface oxide layer of the Sm2 Fe17N3 grains. However, the Sm-Fe-Cu-Al binder was contaminated by carbon and nitrogen, which originated from the organic solvent used as the milling medium during pulverization. To prevent carbon and nitrogen contamination, the Sm-Fe- Cu-Al alloy was added directly on the surface of the Sm2Fe17N3 grains by sputtering. Comparing the recovered coercivity per unit amount of the added binder the uncontaminated binder-coated sample had a higher coercivity recovery effect than the milled binder-added sample. These results suggested that sufficient addition of the contamination-free Sm-Fe-Cu-Al binder has the possibility to reduce the amount of binder necessary to produce a high coercive Sm2Fe17N3 magnet.

Coercive and legitimate authority impact tax honesty: evidence from behavioral and ERP experiments

PubMed Central

Pfabigan, Daniela M.; Lamm, Claus; Kirchler, Erich; Hofmann, Eva

2017-01-01

Abstract Cooperation in social systems such as tax honesty is of central importance in our modern societies. However, we know little about cognitive and neural processes driving decisions to evade or pay taxes. This study focuses on the impact of perceived tax authority and examines the mental chronometry mirrored in ERP data allowing a deeper understanding about why humans cooperate in tax systems. We experimentally manipulated coercive and legitimate authority and studied its impact on cooperation and underlying cognitive (experiment 1, 2) and neuronal (experiment 2) processes. Experiment 1 showed that in a condition of coercive authority, tax payments are lower, decisions are faster and participants report more rational reasoning and enforced compliance, however, less voluntary cooperation than in a condition of legitimate authority. Experiment 2 confirmed most results, but did not find a difference in payments or self-reported rational reasoning. Moreover, legitimate authority led to heightened cognitive control (expressed by increased MFN amplitudes) and disrupted attention processing (expressed by decreased P300 amplitudes) compared to coercive authority. To conclude, the neuronal data surprisingly revealed that legitimate authority may led to higher decision conflict and thus to higher cognitive demands in tax decisions than coercive authority. PMID:28402477

Coercive treatment and autonomy in psychiatry.

PubMed

Sjöstrand, Manne; Helgesson, Gert

2008-02-01

There are three lines of argument in defence of coercive treatment of patients with mental disorders: arguments regarding (1) societal interests to protect others, (2) the patients' own health interests, and (3) patient autonomy. In this paper, we analyse these arguments in relation to an idealized case, where a person with a mental disorder claims not to want medical treatment for religious reasons. We also discuss who should decide what in situations where patients with mental disorders deny treatment on seemingly rational grounds. We conclude that, in principle, coercive treatment cannot be defended for the sake of protecting others. While coercive actions can be acceptable in order to protect close family and others, medical treatment is not justified for such reasons but should be given only in the interest of patients. Coercive treatment may be required in order to promote the patient's health interests, but health interests have to waive if they go against the autonomous interests of the patient. We argue that non-autonomous patients can have reasons, rooted in their deeply-set values, to renounce compulsory institutional treatment, and that such reasons should be respected unless it can be assumed that their new predicaments have caused them to change their views.

Temperature stability of coercivity in mischmetal-Fe-Co-B melt-spun ribbons

NASA Astrophysics Data System (ADS)

Li, Rui; Zhang, Hong-Rui; Liu, Yao; Zuo, Shu-Lan; Xiong, Jie-Fu; Zuo, Wen-Liang; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

2018-05-01

Coercivity temperature coefficient (β) of the permanent magnet depends on its intrinsic magnetic properties and microstructure. In this paper, the relationship between β and the temperature stabilities of magnetocrystalline anisotropy field (H a ) and saturation magnetization (M s ) as well as the microstructure is discussed. Regarding two concerned microstructural factors: grain size and grain boundary, coercivity thermal-stabilities of MM13.5Fe79.5B7 (MM-mischmetal: unseparated La-Ce-Pr-Nd alloy) and MMxFe94‑xB6 (x = 12, 13, 14, 15, 16, 19) melt-spun ribbons, respectively, are investigated. High β values near the theoretical limit are obtained either by decreasing grain size or by reducing MM percentage. In addition, coercivities above room temperature of MM13.5Fe79.5‑yCoyB7 (y = 0, 3, 6, 9, 12, 15) melt-spun ribbons are measured. The detailed influences of Co substitutions on β are analyzed, and the weak temperature dependence of M s is proved to the reason for the observed decrease of β. These findings suggest that proper strategy to minimize local stray fields is the key to enhance coercivity thermal-stability of 2:14:1 structure magnet.

Chemical Synthesis of Next Generation High Energy Product Hybrid SmCo Permanent Magnets for High Temperature Applications

DTIC Science & Technology

2010-08-01

among CoxC, AINiCo and Ba / Sr ferrite magnets. AINiCo is shown to exhibit high (BH)max, 35 kJmŗ, but a low intrinsic coercivity, mostly ə kOe...whereas Ba / Sr ferrite features high intrinsic coercivity, 3-4.5 kOe, but typical values of (BH)max below 25 kJm-3. However, the multiple...coercivity of cobalt carbide nanoparticles is compared with free powders of AINiCo and ceramic magnets of the Ba / Sr hexaferrite type. Curie temperatures near

Psychometric properties and reliability of the Assessment Screen to Identify Survivors Toolkit for Gender Based Violence (ASIST-GBV): results from humanitarian settings in Ethiopia and Colombia.

PubMed

Vu, Alexander; Wirtz, Andrea; Pham, Kiemanh; Singh, Sonal; Rubenstein, Leonard; Glass, Nancy; Perrin, Nancy

2016-01-01

Refugees and internally displaced persons who are affected by armed-conflict are at increased vulnerability to some forms of sexual violence or other types of gender-based violence. A validated, brief and easy-to-administer screening tool will help service providers identify GBV survivors and refer them to appropriate GBV services. To date, no such GBV screening tool exists. We developed the 7-item ASIST-GBV screening tool from qualitative research that included individual interviews and focus groups with GBV refugee and IDP survivors. This study presents the psychometric properties of the ASIST-GBV with female refugees living in Ethiopia and IDPs in Colombia. Several strategies were used to validate ASIST-GBV, including a 3 month implementation to validate the brief screening tool with women/girls seeking health services, aged ≥15 years in Ethiopia (N = 487) and female IDPs aged ≥ 18 years in Colombia (N = 511). High proportions of women screened positive for past-year GBV according to the ASIST-GBV: 50.6 % in Ethiopia and 63.4 % in Colombia. The factor analysis identified a single dimension, meaning that all items loaded on the single factor. Cronbach's α = 0.77. A 2-parameter logistic IRT model was used for estimating the precision and discriminating power of each item. Item difficulty varied across the continuum of GBV experiences in the following order (lowest to highest): threats of violence (0.690), physical violence (1.28), forced sex (2.49), coercive sex for survival (2.25), forced marriage (3.51), and forced pregnancy (6.33). Discrimination results showed that forced pregnancy was the item with the strongest ability to discriminate between different levels of GBV. Physical violence and forced sex also have higher levels of discrimination with threats of violence discriminating among women at the low end of the GBV continuum and coercive sex for survival among women at the mid-range of the continuum. The findings demonstrate that the ASIST-GBV has strong psychometric properties and good reliability. The tool can be used to screen and identify female GBV survivors confidentially and efficiently among IDPs in Colombia and refugees in Ethiopia. Early identification of GBV survivors can enable safety planning, early referral for treatment, and psychosocial support to prevent long-term harmful consequence of GBV.

The paradox of progress: translating Evan Stark's Coercive Control into legal doctrine for abused women.

PubMed

Hanna, Cheryl

2009-12-01

This article examines Evan Stark's model of coercive control and what this paradigm shift might mean for the law. Coercive control can help redefine both criminal offenses involving domestic violence and defenses available to women who kill their abusers. This redefinition would shift the law away from incident-based violence and toward a more comprehensive and accurate paradigm that accounts for the deprivation of a woman's autonomy within the context of an abusive relationship. Such a change would likely provide more effective state intervention into what were once considered private relationships. Yet, this approach may also have some unintended consequences, including refocusing the law on a victim's mental state and complicity in her own abuse rather than on the harm caused by abusive men. Thus, although the law should more fully account for coercive control, lawyers must be cautiously optimistic in implementing Stark's proposed reforms.

Ultimate intrinsic-coercivity samarium-cobalt magnet: An Earth-based feasibility study for space-shuttle missions. [containerless melts

NASA Technical Reports Server (NTRS)

Das, D. K.; Kumar, K.; Frost, R. T.; Chang, C. W.

1980-01-01

Techniques for containerless melting and solidification of the samarium-cobalt alloy without excessive oxidation were developed. The rationale for extending these experiments in a weightless environment is also discussed. The effect of oxygen content from 0.15 to 0.63 weight percent and grain size in the range of 2 to 10 micrometers has been examined on arc-plasma-sprayed SmCo5 magnets. Contrary to expectations, the larger grain sizes tended to improve the coercivities. This was attributed to an increase in homogeneity resulting from higher temperature treatments used to produce larger grain size. No significant differences in coercivity were observed on the basis of oxygen content in the range examined. It is expected that more meaningful data on the relationship between oxygen content and coercivity will be seen when the oxygen content can be lowered to less than 0.1 weight percent.

Sm5(Fe,Ti)17 melt-spun ribbons with high coercivity

NASA Astrophysics Data System (ADS)

Saito, Tetsuji; Horita, Toru

2018-05-01

It has previously been reported that annealing of amorphous Sm5Fe17 melt-spun ribbon resulted in the formation of the Sm5Fe17 phase and the resultant Sm5Fe17 melt-spun ribbon exhibited a high coercivity. However, the annealing condition of the amorphous Sm5Fe17 melt-spun ribbon was somewhat critical and it was not easy to obtain Sm5Fe17 grains with high coercivity. In the present study, it was found that the small substitution of Ti for Fe in the Sm5Fe17 melt-spun ribbon stabilized the Sm5Fe17 phase. Annealed Sm5Fe16.7Ti0.3 melt-spun ribbon consisted of small and homogeneous Sm5(Fe,Ti)17 grains and exhibited a higher coercivity than the annealed Sm5Fe17 melt-spun ribbon.

Grain boundary diffusion of Dy films prepared by magnetron sputtering for sintered Nd–Fe–B magnets

NASA Astrophysics Data System (ADS)

Chen, W.; Luo, J. M.; Guan, Y. W.; Huang, Y. L.; Chen, M.; Hou, Y. H.

2018-05-01

Dy films, deposited on the surface of sintered Nd–Fe–B magnets by magnetron sputtering, were employed for grain boundary diffusion source. High coercivity sintered Nd–Fe–B magnets were successfully prepared. Effects of sputtering power and grain boundary diffusion processes (GBDP) on the microstructure and magnetic properties were investigated in detail. The dense and uniform Dy films were beneficial to prepare high coercivity magnets by GBDP. The maximum coercivity value of 1189 kA m‑1 could be shown, which was an amplification of 22.3%, compared with that of as-prepared Nd–Fe–B magnet. Furthermore, the improved remanence and maximum energy product were also achieved through tuning grain boundary diffusion processes. Our results demonstrated that the formation of (Nd, Dy)2Fe14B shell surrounding Nd2Fe14B grains and fine, uniform and continuous intergranular RE-rich phases jointly contribute to the improved coercivity.

Coercivity enhancement in hot deformed Nd2Fe14B-type magnets by doping low-melting RCu alloys (R = Nd, Dy, Nd + Dy)

NASA Astrophysics Data System (ADS)

Lee, Y. I.; Huang, G. Y.; Shih, C. W.; Chang, W. C.; Chang, H. W.; You, J. S.

2017-10-01

Magnetic properties of the anisotropic NdFeB magnets prepared by hot pressing followed by die-upsetting NdFeB MQU-F powders doped with low-melting RCu alloy powders were explored, where RCu stands for Nd70Cu30, Dy70Cu30 and (Nd0.5Dy0.5)70Cu30, respectively. In addition, the post-annealing at 600 °C was employed to modify the microstructures and the magnetic properties of the hot deformed magnets. It is found that doping RCu alloy powders is effective in enhancing the coercivity of the hot deformed NdFeB magnets from 15.1 kOe to 16.3-19.5 kOe. For Nd70Cu30-doped magnets, the increment of coercivity is only 1.2 kOe. Meanwhile, Dy70Cu30-doped and (Nd0.5Dy0.5)70Cu30-doped magnets show an almost identical enhancement of coercivity of about 4.4 kOe. Importantly, the latter magnet shows a beneficial effect of reducing the usage of Dy from 1.6 wt% to 0.8 wt%. TEM analysis shows that nonmagnetic Nd, Dy and Cu appear at grain boundary and isolate the magnetic grains, leading to an enhancement of coercivity. Doping lower melting point Dy-lean (Nd0.5Dy0.5)70Cu30 powders into commercial MQU-F powders for making high coercivity hot deformed NdFeB magnets might be a potential and economic way for mass production.

Coercivity scaling in antidot lattices in Fe, Ni, and NiFe thin films

NASA Astrophysics Data System (ADS)

Gräfe, Joachim; Schütz, Gisela; Goering, Eberhard J.

2016-12-01

Antidot lattices can be used to artificially engineer magnetic properties in thin films, however, a conclusive model that describes the coercivity enhancement in this class of magnetic nano-structures has so far not been found. We prepared Fe, Ni, and NiFe thin films and patterned each with 21 square antidot lattices with different geometric parameters and measured their hysteretic behavior. On the basis of this extensive dataset we are able to provide a model that can describe both the coercivity scaling over a wide range of geometric lattice parameters and the influence of different materials.

Coercive and legitimate authority impact tax honesty: evidence from behavioral and ERP experiments.

PubMed

Gangl, Katharina; Pfabigan, Daniela M; Lamm, Claus; Kirchler, Erich; Hofmann, Eva

2017-07-01

Cooperation in social systems such as tax honesty is of central importance in our modern societies. However, we know little about cognitive and neural processes driving decisions to evade or pay taxes. This study focuses on the impact of perceived tax authority and examines the mental chronometry mirrored in ERP data allowing a deeper understanding about why humans cooperate in tax systems. We experimentally manipulated coercive and legitimate authority and studied its impact on cooperation and underlying cognitive (experiment 1, 2) and neuronal (experiment 2) processes. Experiment 1 showed that in a condition of coercive authority, tax payments are lower, decisions are faster and participants report more rational reasoning and enforced compliance, however, less voluntary cooperation than in a condition of legitimate authority. Experiment 2 confirmed most results, but did not find a difference in payments or self-reported rational reasoning. Moreover, legitimate authority led to heightened cognitive control (expressed by increased MFN amplitudes) and disrupted attention processing (expressed by decreased P300 amplitudes) compared to coercive authority. To conclude, the neuronal data surprisingly revealed that legitimate authority may led to higher decision conflict and thus to higher cognitive demands in tax decisions than coercive authority. © The Author (2017). Published by Oxford University Press.

Magnetization reversal mechanism and coercivity enhancement in three-dimensional granular Nd-Fe-B magnets studied by micromagnetic simulations

NASA Astrophysics Data System (ADS)

Lee, Jae-Hyeok; Choe, Jinhyeok; Hwang, Shinwon; Kim, Sang-Koog

2017-08-01

We studied the mechanism of magnetization reversals and coercivity enhancements in three-dimensional (3D) granular Nd-Fe-B permanent magnets using finite-element micromagnetic simulations. The magnetization reversals in the hard magnets consisting of hard-phase grains separated by relatively soft-phase grain boundaries were analyzed with reference to the simulation results for the magnetic field-dependent distributions of the local magnetizations. The saturation magnetization of the grain-boundary phase plays a crucial role in the transition between nucleation- and domain-wall-propagation-controlled reversal processes. The smaller the saturation magnetization of the grain-boundary phase is, the more preferable is the nucleation-controlled process, which results in a larger coercivity. The exchange stiffness of the grain-boundary phase determines the preferred paths of domain-wall propagations, whether inward into grains or along the grain boundaries for relatively small and large exchange stiffness, respectively. However, the exchange stiffness of the grain-boundary phase alone does not significantly contribute to coercivity enhancement in cases where the size of hard-phase grains is much greater than the exchange length. This work paves the way for the design of high-performance hard magnets of large coercivity and maximum-energy-product values.

[Coercive Measures in Child and Adolescent Psychiatry in Post-war Germany, Using the Example of the "Pflege- und Beobachtungsstation" in the State Psychiatric Hospital Weissenau (1951-1966)].

PubMed

Afschar-Hamdi, Sima; Schepker, Klaus

2017-09-01

Coercive Measures in Child and Adolescent Psychiatry in Post-war Germany, Using the Example of the "Pflege- und Beobachtungsstation" in the State Psychiatric Hospital Weissenau (1951-1966) The patient admissions at the children's ward of the State Psychiatric Hospital Weissenau in the years 1951, 1956, 1961 and 1966 were analyzed regarding documented coercive measures. Shortage of staff, mainly inadequately skilled personnel, a mixing of age groups in the patient cohort, neurological and psychiatric disorders and of patients who were in need of nursing and of those who needed treatment constituted the general work environment. Coercive measures against patients, mostly disproportionate isolations, were a constant part of daily life on the ward. This affected in particular patients who had to stay longer at the hospital and whose stay was financed by public authority. The uselessness of such measures was known, which can be seen e. g. in the Caretaker's Handbook of that time and the comments in the patient files. The situation still escalated in some cases (for example by transfer to an adult ward). For a long time, coercive measures against patients were part of everyday life at the children's ward of the Weissenau; the actual figures are suspected to be much higher.

Plagioclase-Hosted Magnetite Inclusions From the Bushveld Complex

NASA Astrophysics Data System (ADS)

Feinberg, J. M.; Scott, G. R.; Renne, P. R.; Wenk, H.

2004-12-01

Gabbros from the Main Zone of the 2.064 Ga Bushveld Complex have long been known to possess unusually stable magnetizations due to the presence of high coercivity, exsolved magnetite inclusions in plagioclase and clinopyroxene. The paleomagnetic pole for these rocks has been used to anchor apparent polar wander paths for the Kaapval craton during the Early-Mid Proterozoic. To better understand the rock magnetic properties of silicate-hosted magnetite inclusions, oriented paleomagnetic samples of gabbro were collected from quarries near Belfast and Rustenberg, South Africa, sampling the eastern and western limbs of the Complex, respectively. Plagioclase composition at both sites ranges from An55 (rims) to An65 (cores) based on optical and electron microprobe data. Four kinds of inclusions are present within the plagioclase: elongate magnetite needles, nanometer-scale magnetite particles (responsible for the "cloudy" appearance of some crystals), translucent brown hematite/ilmenite platelets, and colorless euhedral inclusions of pyroxene and/or feldspar. Magnetite inclusions are most abundant at the cores of the plagioclase crystals. Orientations of the needles and the platelets are crystallographically controlled by the silicate host. Although the elongation direction of the magnetite inclusions can occur in any of five possible orientations, only two or three of these directions dominates each plagioclase crystal. Alternating field demagnetization of bulk samples (NRM = 1.5 x 101 A m-1) shows univectorial remanence with average median destructive fields (MDF) of 115 mT (Belfast) and 90 mT (Rustenberg). AF demagnetization of single plagioclase crystals (NRM = 100 A m-1) also shows single component remanence with average MDFs >150 mT. The NRM coercivity spectra of single plagioclase crystals are indistinguishable from that of the bulk samples. When normalized to their abundance in bulk samples the magnetite-bearing plagioclase fully accounts for the NRM of Bushveld gabbros at both sites. Close examination of the inclusions' interiors using magnetic force microscopy shows no ulvöspinel exsolution as observed in other silicate exsolved titanomagnetites with comparably high coercivities. Consequently, we interpret the high coercivities of the inclusions to be a product of their small size and extreme shape anisotropy. Single crystals of plagioclase demonstrate a strong anisotropy of IRM acquisition (see Scott, et al. this conference). Additionally, electron backscatter diffraction (EBSD) orientation indexing shows a strongly preferred orientation for plagioclase and pyroxene (with (010)plag and (100)pyr parallel to subhorizontal layering) consistent with gravitational settling within a magma chamber. Thus, there are two anisotropies (silicate preferred orientation and magnetite inclusion remanence) to consider when describing the ancient magnetic field present during the emplacement of the Bushveld.

Longitudinal recording on FePt and FePtX (X = B, Ni) intermetallic compounds

NASA Astrophysics Data System (ADS)

Li, Ning

1999-11-01

Near field recording on high coercivity FePt intermetallic compound media using a high Bsat write element was investigated. Untextured FePt media were prepared by magnetron sputtering on ZrO2 disks at a substrate temperature of 450°C, with post annealing at 450°C for 8 hrs. Both multilayer and cosputtered precursors produced the ordered tetragonal L10 phase with high coercivity between 5kOe and 12kOe. To improve readback noise decrease magnetic domain size, FePtB media were subsequently prepared by cosputtering. Over-write, roll-off, signal to noise ratio and non-linear transition shift (NLTS) ere measured by both metal in gap (MIG) and merged MR heads. FePtB media showed similar NLTS to commercial CoCrPtTa longitudinal media, but 5dB lower signal to noise ratio. By operating recording transducers in near contact, reasonable values of (>30dB) could be obtained. VSM Rotational Transverse Magnetization has been used for measuring the anisotropy field of magnetic thin films. Magnetization reversal during rotation of a 2D isotropic an applied field is discussed. The relationship between the transverse magnetization My and the applied field H was numerically solved. An excellent approximation for the transverse magnetization is found to be: My/Ms=A(1- H/Hk) 2.5, where A = 1.1434, and Hk is the anisotropy field. For curve fitting to experimental data, both A and Hk were used as fitting parameters. Comparison between a constructed torque hysteresis method and this VSM RTM method have been made theoretically and experimentally. Both results showed that VSM RTM will give better extrapolation of the anisotropy field. The torque measurement will slightly overestimate the anisotropy field. The anisotropy fields of FePt and FePtX (X = B, Ni) films were characterized using this VSM RTM technique with comparison to a CoCrTaPt disk. Anisotropy energy was derived. Hc/Hk was used as an indicator for coherent rotation of a single domain. Interactions between magnetic domains were characterized by Kelly-Henkel plot and interactive field factor (IFF). Correlation between coercive force and magnetic anisotropy of grains and the degree of magnetic isolation among grains were discussed. B and Ni were used as diluting agents to the FePt system to decrease saturation magnetization, coercivity, anisotropy field and anisotropy energy. They also decrease the magnetic coupling between neighboring domains, and promote coherent rotation inside each domain.

5 CFR 950.108 - Preventing coercive activity.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Preventing coercive activity. 950.108 Section 950.108 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... giving is fundamental to Federal fundraising activities. Actions that do not allow free choices or create...

Comparative magnetic measurements on social insects

NASA Astrophysics Data System (ADS)

Ferreira, Jandira; Cernicchiaro, Geraldo; Winklhofer, Michael; Dutra, Humberto; de Oliveira, Paulo S.; S. Esquivel, Darci M.; Wajnberg, Eliane

2005-03-01

Biogenic magnetite has been detected in several species of social insects and may well form the basis of a magnetic sensory system in these animals, although other physiological functions are possible, too. We report here on hysteresis measurements on honeybees ( Apis mellifera) and the termite Neocapritermes opacus. The ratio of saturation remanence to saturation magnetization, Jrs/ Js, was determined as 0.11 (0.15) in bees (termite), the coercive force Hc as 90 (50 Oe). The magnetic remanence is generally low (of the order of 10 -6 emu per individual). The values obtained are similar to the ones reported previously on a migratory ant species, which suggests that biomineralization of magnetic material in social insects may underlie a generic process.

Magnetic Properties and Phase Composition of Metamaterials Based on an Opal Matrix with 3 d-Transition Metal Particles

NASA Astrophysics Data System (ADS)

Rinkevich, A. B.; Korolev, A. V.; Samoilovich, M. I.; Perov, D. V.; Nemytova, O. V.

2018-02-01

The magnetic properties of metamaterials based on an opal matrix with transition-metal (iron, nickel, cobalt) particles have been studied. Magnetization curves and magnetic hysteresis loops have been measured and the dependences of real and imaginary parts of magnetization have been determined using the dynamic ac susceptibility measuring procedure. Structural studies of metamaterials have been performed. The saturation magnetization and coercive force of the studied metamaterials have been found to depend weakly on the temperature. The temperature dependence of magnetic susceptibility at a temperature above 30 K can be described adequately by Curie-Weiss law and, at lower temperature, deviates from the law.

MAGNETIC MEASUREMENT OF THE PLASTIC STRESS-STRAIN CURVE OF MULTICRYSTALLINE NICKEL (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwink, Ch.; Zankl, G.

1962-01-01

Ballistic measurements of the coercive force H/sub c/ and the initial permeability mu /sub alpha / were made on nlckel wires, and their dependence on plastic tensile deformation was followed. The results are shown graphically. H/ sub c/ and 1/ mu /sub alpha / start to increase at a given tensile stress with the introduction of plastic expansion and increases almost linearly with the tensile stress applied. At a tensile stress of 7.2 plus or minus 0.5 kp/mm/sup 2/ both curves have noticable bends. The bend point is related by a special process to the plastic deformation of the multicrystallinemore » material. (J.S.R.)« less

Effect of neutron irradiation on magnetic properties in the low alloy Ni-Mo steel SA508-3

NASA Astrophysics Data System (ADS)

Park, D. G.; Kim, C. G.; Kim, H. C.; Hong, J. H.; Kim, I. S.

1997-04-01

The B-H hysteresis loop and Barkhausen noise have been measured in the neutron irradiated SA508 steel of 45 μm thickness. The coercive force of B-H loop showed a slow change up to a neutron dose of 1014 n/cm2 and increased by 15.4% for a 1016 n/cm2 dose sample compared with that of the unirradiated one, related to the domain wall motion hindered by the increased defects. However, the amplitude of Barkhausen noise reflecting the wall motion decreased slowly up to 1014 n/cm2 irradiation, followed by a rapid decrease of 37.5% at 1016 n/cm2.

Structure and magnetic properties of Co-Ni-Mn alloy coatings (part 2)

NASA Astrophysics Data System (ADS)

Schmidt, V. V.; Zhikhareva, I. G.; Smirnova, N. V.; Shchipanov, V. P.

2018-03-01

Using the method of high-frequency alternating current (HFAC), based on the preliminary model forecasting of the ratio of metal ions in the electrolyte and the phase composition of the coating, Co-Ni-Mn alloy precipitates with the specified magnetic properties are obtained. It is shown that precipitation with a hexagonal close-packed α-Co phase has the highest coercive force. The presence of a free phase in a small amount (2.1 - 2.6% of weight) of Mn increases the ferromagnetic properties of films due to the domain structures with a poorly defecting α-Mn crystal lattice. The adjustable amount of the amorphous Co(OH)2 phase provides the nanostructure dimensions of the crystals.

A harsh parenting team? Maternal reports of coparenting and coercive parenting interact in association with children's disruptive behaviour.

PubMed

Latham, Rachel M; Mark, Katharine M; Oliver, Bonamy R

2017-05-01

Parenting and coparenting are both important for children's adjustment, but their interaction has been little explored. Using a longitudinal design and considering two children per family, we investigated mothers' and fathers' perceptions of coparenting as moderators of associations between their coercive parenting and children's disruptive behaviour. Mothers and fathers from 106 'intact' families were included from the Twins, Family and Behaviour study. At Time 1 (M child age  = 3 years 11 months, SD child age  = 4.44 months) parents reported on their coercive parenting and children's disruptive behaviour via questionnaire; at Time 2 (M child age  = 4 years 8 months, SD child age  = 4.44 months) perceptions of coparenting and the marital relationship were collected by telephone interview. Questionnaire-based reports of children's disruptive behaviour were collected at follow-up (M child age  = 5 years 11 months, SD child age  = 5.52 months). Multilevel modelling was used to examine child-specific and family-wide effects. Conservative multilevel models including both maternal and paternal perceptions demonstrated that maternal perceptions of coparenting and overall coercive parenting interacted in their prediction of parent-reported child disruptive behaviour. Specifically, accounting for perceived marital quality, behavioural stability, and fathers' perceptions, only in the context of perceived higher quality coparenting was there a positive association between mother-reported overall coercive parenting and children's disruptive behaviour at follow-up. When combined with highly coercive parenting, maternal perceptions of high quality coparenting may be detrimental for children's adjustment. © 2016 Association for Child and Adolescent Mental Health.

Cross-sectional study on nurses' attitudes regarding coercive measures: the importance of socio-demographic characteristics, job satisfaction, and strategies for coping with stress.

PubMed

Bregar, Branko; Skela-Savič, Brigita; Kores Plesničar, Blanka

2018-06-04

Coercive measures are containment methods used in psychiatry to curb patients' disruptive and aggressive behaviours towards themselves, others or objects. The prevalence of the practice of coercive measures in psychiatry is directly related to the attitudes of the staff. When discussing these attitudes, nurses are often particularly singled out. The purpose of the study is to research the impact of individual factors on nurses' attitudes in the decision-making process for the use of coercive measures. A cross-sectional study among all psychiatric nursing staff in Slovenia (n = 367, 79%) was conducted over the years 2013/2014. Standardized questionnaires were used, including a survey of nurses' attitudes to the use of seclusion, the Job Descriptive Index, and the Folkman-Lazarus test. Nurses' attitudes towards special coercive measures are predominantly negative ([Formula: see text] = 11.312, SD = 2.641). The factors that explain a positive attitude are as follows: female gender (β = - 0.236, p <  0.001), fewer years of service (β = - 0.149, p = 0.023), emotion-focused strategies of coping with stress (β = 0.139, p = 0.020), and less-threatening patient behaviour (β = 0.157, p = 0.012). The effects of some known factors did not prove important in the model. Newly recognized factors are "less-threatening patient behaviour" and "emotion-focused strategies of coping with stress". Therefore, attitudes towards special coercive measures in psychiatry must be regarded as contextualized, interactive, and multidimensional phenomena that cannot be explained merely through a defined set of factors.

Magnetic nanostructuring and overcoming Brown's paradox to realize extraordinary high-temperature energy products

NASA Astrophysics Data System (ADS)

Balasubramanian, Balamurugan; Mukherjee, Pinaki; Skomski, Ralph; Manchanda, Priyanka; Das, Bhaskar; Sellmyer, David J.

2014-09-01

Nanoscience has been one of the outstanding driving forces in technology recently, arguably more so in magnetism than in any other branch of science and technology. Due to nanoscale bit size, a single computer hard disk is now able to store the text of 3,000,000 average-size books, and today's high-performance permanent magnets--found in hybrid cars, wind turbines, and disk drives--are nanostructured to a large degree. The nanostructures ideally are designed from Co- and Fe-rich building blocks without critical rare-earth elements, and often are required to exhibit high coercivity and magnetization at elevated temperatures of typically up to 180 °C for many important permanent-magnet applications. Here we achieve this goal in exchange-coupled hard-soft composite films by effective nanostructuring of high-anisotropy HfCo7 nanoparticles with a high-magnetization Fe65Co35 phase. An analysis based on a model structure shows that the soft-phase addition improves the performance of the hard-magnetic material by mitigating Brown's paradox in magnetism, a substantial reduction of coercivity from the anisotropy field. The nanostructures exhibit a high room-temperature energy product of about 20.3 MGOe (161.5 kJ/m3), which is a record for a rare earth- or Pt-free magnetic material and retain values as high as 17.1 MGOe (136.1 kJ/m3) at 180°C.

"He forced me to love him": putting violence on adolescent sexual health agendas.

PubMed

Wood, K; Maforah, F; Jewkes, R

1998-07-01

Violence against women within sexual relationships is a neglected area in public health despite the fact that, in partially defining women's capacity to protect themselves against STDs, pregnancy and unwanted sexual intercourse, it directly affects female reproductive health. This paper presents the findings of a qualitative study conducted among Xhosa-speaking adolescent women in South Africa which revealed male violent and coercive practices to dominate their sexual relationships. Conditions and timing of sex were defined by their male partners through the use of violence and through the circulation of certain constructions of love, intercourse and entitlement to which the teenage girls were expected to submit. The legitimacy of these coercive sexual experiences was reinforced by female peers who indicated that silence and submission was the appropriate response. Being beaten was such a common experience that some peers were said to perceive it to be an expression of love. Informants indicated that they did not terminate the relationships for several reasons: beyond peer pressure and the probability of being subjected to added abuse for trying to end a relationship, teenagers said that they perceived that their partners loved them because they gave them gifts of clothing and money. The authors argue that violence has been particularly neglected in adolescent sexuality arenas, and propose new avenues for sexuality research which could inform the development of much-needed adolescent sexual health interventions.

A strong pinning model for the coercivity of die-upset Pr-Fe-B magnets

NASA Astrophysics Data System (ADS)

Pinkerton, F. E.; fürst, C. D.

1991-04-01

We have measured the temperature dependence of the intrinsic coercivity Hci(T) between 5 and 565 K in a die-upset Pr-Fe-B magnet. Over a very wide temperature range up to 477 K, Hci(T) is in excellent agreement with a model for strong domain-wall pinning by a random array of pinning sites proposed by Gaunt [P. Gaunt, Philos. Mag. B 48, 261 (1983)]. The model includes both the temperature dependence of the intrinsic magnetic properties of the Pr2Fe14B phase and the effects of thermal activation of domain walls over the pinning barrier. The pinning sites are modeled as nonmagnetic planar inhomogeneities at the boundaries between platelet-shaped Pr2Fe14B grains. We develop an expression for the maximum pinning force per site, f, and derive the model prediction that (Hci/γHA)1/2 varies linearly with (T/γ)2/3, where HA and γ are the magnetocrystalline anisotropy field and the domain-wall energy per unit area of the Pr2Fe14B phase, respectively. Significant deviations from the model are observed only at high temperature, suggesting that the strong pinning model is no longer valid very close to the Curie temperature (565 K). The present result agrees with the model fit obtained for a die-upset Nd-Fe-B magnet.

Study of microstress state of P91 steel using complementary mechanical Barkhausen, magnetoacoustic emission, and X-ray diffraction techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustyniak, Bolesław, E-mail: bolek@mif.pg.gda.pl; Piotrowski, Leszek; Maciakowski, Paweł

2014-05-07

The paper deals with assessment of microstress state of martensite P91 steel using three complementary techniques: mechanical Barkhausen emission, magnetoacoustic emission (MAE), and X-ray diffraction (XRD) profile analysis. Magnetic coercivity Hc and microstructure were investigated with inductive magnetometry and magnetic force microscopy (MFM), respectively. Internal stress level of P91 steel was modified by heat treatment. Steel samples were austenitized, quenched, and then tempered at three temperatures (720 °C, 750 °C, and 780 °C) during increasing time (from 15 min up to 240 min). The microstrain level ε{sub i} was evaluated using Williamson–Hall method. It was revealed that during tempering microstrain systematically decreases from ε{sub i} = 2.5more » × 10{sup −3} for as quenched state down to ε{sub i} = 0.3 × 10{sup −3} for well tempered samples. Both mechanical hardness (Vicker's HV) and magnetic hardness (coercivity) decrease almost linearly with decreasing microstrain while the MAE and MBE intensities strongly increase. Tempering leads to evident shift of the MeBN intensity maximum recorded for the first load towards lower applied strain values and to increase of MAE intensity. This indicates that the microstress state deduced by magnetic techniques is correlated with microstrains evaluated with XRD technique.« less

Tailoring magnetic properties in arrays of pulse-electrodeposited Co nanowires: The role of Cu additive

NASA Astrophysics Data System (ADS)

Esmaeili, A.; Almasi Kashi, M.; Ramazani, A.; Montazer, A. H.

2016-01-01

In this study, we aim to report the role of Cu additive in arrays of pulse-electrodeposited Co nanowires (NWs) with diameters from 30 to 75 nm, embedded in porous aluminum oxide templates. This features the role of Cu additive in composition and crystalline characteristics as well as in the magnetic properties of Co NWs. Increasing the duration of off-time between pulses during the electrodeposition of Co NWs made it possible to increase the amount of Cu content, so that Co-rich CoCu NWs were obtained. The parallel coercivity and squareness values increased up to 1500 Oe and 0.8 for 30 nm diameter Co94Cu6 NWs, starting from 500 Oe and 0.3 for pure Co NWs. On the other hand, although there was a substantial difference between the crystalline characteristics of 75 nm diameter pure Co and CoCu NWs, no considerable change in their magnetic properties was observed using hysteresis loop measurements. In this respect, the first-order reversal curve (FORC) analysis revealed strong inter-wire magnetostatic interactions for the CoCu NWs. Moreover, we studied the effect of thermal annealing, which resulted in an increase in the coercivity of CoCu NWs with different diameters up to 15%. As a result, the addition of small amount of Cu provides an alternative approach to tailoring the magnetic properties of Co NWs.

Empowerment, Coercive Persuasion and Organizational Learning: Do They Connect?

ERIC Educational Resources Information Center

Schein, Edgar H.

1999-01-01

Individual learning in organizations can be de facto coercive persuasion when organizational learning and culture change require that learners develop appropriate attitudes and thinking. If the goal of organizational learning--innovative organizations--is accepted, moral choices that restrict individual freedom must be made. (SK)

Mechanical stress modified ferroelectric aging behavior

NASA Astrophysics Data System (ADS)

Xu, Tingting; Kan, Yi; Jin, Yaming; Sun, Hui; Du, Yingchao; Wu, Xiumei; Bo, Huifeng; Cai, Wei; Huang, Fengzhen; Lu, Xiaomei; Zhu, Jinsong

2013-05-01

Mechanical stress effect on aging behavior of Bi3.25La0.75Ti3O12 (BLT) and PbZr0.53Ti0.47O3 (PZT) films was investigated. It is found that the remnant polarization decreases with time while the coercive field increases in stress-free BLT films. For unconfined PZT films, both the remnant polarization and the coercive field decrease as time elapses. The applied tensile stress weakens the aging of remnant polarization of BLT films but strengthens the aging of coercive field, while the applied tensile stress possesses opposite effect. In contrary, the applied compressive stress simultaneously improves the aging behavior of both remnant polarization and coercive field of PZT films. Mechanical-stress-induced variation of domain wall mobility in different materials was suggested as the possible origin of these observations. This work indicates that the aging behavior modification using stress could be realized, and it is helpful for promoting the reliability of ferroelectric films for industrial applications.

Anisotropic nanocrystalline MnBi with high coercivity at high temperature

NASA Astrophysics Data System (ADS)

Yang, J. B.; Yang, Y. B.; Chen, X. G.; Ma, X. B.; Han, J. Z.; Yang, Y. C.; Guo, S.; Yan, A. R.; Huang, Q. Z.; Wu, M. M.; Chen, D. F.

2011-08-01

Magnetic hard nanocrystalline MnBi has been prepared by melt spinning and subsequent low temperature annealing. A coercivity of 2.5 T can be achieved at 540 K for MnBi with an average grain size of about 20-30 nm. The coercivity iHc, mainly controlled by the coherent magnetization rotation, shows a strong dependence on the time of grinding and exhibits a positive temperature coefficient from 100 up to 540 K. The unique temperature dependent behavior of the coercivity (magnetocrystalline anisotropy) has a relationship with the variations in the crystal lattice ratio of c/a with temperatures. In addition, discontinuity can not be found in the lattice parameters of a, c, and c/a ratio at the magnetostructural transition temperature. The nanocrystalline MnBi powder fixed in an epoxy resin and under an applied magnetic field of 24 kOe shows a maximum energy product of 7.1 MGOe at room temperature and shows anisotropic characteristics with high Mr/Ms ratio up to 560 K.

Domain wall pinning on strain relaxation defects (stacking faults) in nanoscale FePd (001)/MgO thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsiao, C. H.; Ouyang, Chuenhou, E-mail: wei0208@gmail.com, E-mail: houyang@mx.nthu.edu.tw; Yao, Y. D.

FePd (001) films, prepared by an electron beam deposition system on MgO(100), exhibit a perpendicular magnetic anisotropy (1.7 × 10{sup 7 }erg/cc) with a high order parameter (0.92). The relation between stacking faults induced by the strain relaxation, which act as strong domain wall pinning sites, and the perpendicular coercivity of (001) oriented L1{sub 0} FePd films prepared at different temperatures have been investigated. Perpendicular coercivity can be apparently enhanced by raising the stacking fault densities, which can be elevated by climbing dissociation of total dislocation. The increased stacking fault densities (1.22 nm{sup −2}) with large perpendicular coercivity (6000 Oe) are obtained for samples preparedmore » at 650 °C. This present work shows through controlling stacking fault density in FePd film, the coercivity can be manipulated, which can be applied in future magnetic devices.« less

Coercivity enhancement of sintered Nd-Fe-B magnets by chemical bath deposition of TbCl{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Shuai, E-mail: gshuai@nimte.ac.cn; Zhang, Xiaofeng; Ding, Guangfei

2014-05-07

The chemical bath deposition (CBD) and the grain boundary diffusion method were combined to diffuse the heavy rare earth for obtain the thick magnets with high coercivity and low heavy rare earth. The jet mill powders were soaked into the alcohol solution of 0.2 wt. % TbCl{sub 3}. A thin layer of TbCl{sub 3} was wrapped to the surface of (PrNd){sub 2}Fe{sub 14}B powder particles. The coercivity of magnet is increased from 11.89 kOe to 14.72 kOe without significant reduction of remanence after grain boundary diffusion in the sintering and the annealing processes. The temperature coefficients of the remanence and themore » coercivity are improved by the substitution of PrNd by Tb in the surface of grains. The highly accelerated temperature/humidity stress test (HAST) results indicate that the CBD magnet has poor corrosion resistance, attributing to the present of Cl atoms in the grain boundaries.« less

Proven practices for reducing aggressive and noncompliant behaviors exhibited by young children at home and at school.

PubMed

Vanderheyden, A; Witt, J C

2000-10-01

One of the single most powerful predictors of aggressive and noncompliant behaviors exhibited in early childhood is coercive parent-child interaction. Coercive parent-child interaction has been linked to multiple negative outcomes in the lives of children. When children learn to relate to their parents and the world in the context of coercive interaction, they are likely to experience significant deficits in the prosocial skills critical to school success. These children are much more likely to experience school failure and teacher and peer rejection. Further, when noncompliant and aggressive children enter school, they are most frequently exposed to a series of ineffective and increasingly restrictive treatments. Proven strategies exist to teach parents and children prosocial ways of interacting and to address these problems in the classroom, but in many cases these types of services are not easily accessible or routinely available. This paper makes recommendations for identifying effective, proven treatment strategies when practitioners observe coercive parent-child interaction or child noncompliance and aggression.

Should Quality School Education Be a Kaizen (Improvement) or an Innovation?

ERIC Educational Resources Information Center

Sun-Keung Pang, Nicholas

1998-01-01

Reviews Hong Kong's School Management Initiative implementation strategies (rational-empirical, power-coercive, and normative-reeducative), compares them with New South Wales, Australia's strategies, and suggests an appropriate strategy for future reforms. In Australia, changes were radical and thorough (using power-coercive strategies), whereas…

Paraphilic Sexual Interests and Sexually Coercive Behavior: A Population-Based Twin Study.

PubMed

Baur, Elena; Forsman, Mats; Santtila, Pekka; Johansson, Ada; Sandnabba, Kenneth; Långström, Niklas

2016-07-01

Prior research with selected clinical and forensic samples suggests associations between paraphilic sexual interests (e.g., exhibitionism and sexual sadism) and sexually coercive behavior. However, no study to date used a large, representative and genetically informative population sample to address the potential causal nature of this association. We used self-report data on paraphilic and sexually coercive behavior from 5990 18- to 32-year-old male and female twins from a contemporary Finnish population cohort. Logistic regression and co-twin control models were employed to examine if paraphilic behaviors were causally related to coercive behavior or if suggested links were confounded by familial (genetic or common family environment) risk factors. Results indicated that associations between four out of five tested paraphilic behaviors (exhibitionism, masochism, sadism, and voyeurism, respectively) and sexually coercive behavior were moderate to strong. Transvestic fetishism was not independently associated with sexual coercion. Comparisons of twins reporting paraphilic behavior with their paraphilic behavior-discordant twin further suggested that associations were largely independent of shared genetic and environmental confounds, consistent with a causal association. In conclusion, similar to previously reported predictive effects of paraphilias on sexual crime recidivism, paraphilic behavior among young adults in the general population increases sexual offending risk. Further, early identification of paraphilic interest and preventive interventions with at-risk individuals might also reduce perpetration of first-time sexual violence.

Improved magnetic properties and thermal stabilities of Pr-Nd-Fe-B sintered magnets by Hf addition

NASA Astrophysics Data System (ADS)

Jiang, Qingzheng; Lei, Weikai; Zeng, Qingwen; Quan, Qichen; Zhang, Lili; Liu, Renhui; Hu, Xianjun; He, Lunke; Qi, Zhiqi; Ju, Zhihua; Zhong, Minglong; Ma, Shengcan; Zhong, Zhenchen

2018-05-01

Nd2Fe14B-type permanent magnets have been widely applied in various fields such as wind power, voice coil motors, and medical instruments. The large temperature dependence of coercivity, however, limits their further applications. We have systematically investigated the magnetic properties, thermal stabilities and coercivity mechanisms of the (Pr0.2Nd0.8)13Fe81-xB6Hfx (x=0, 0.5) nanocrystalline magnets fabricated by a spark plasma sintering (SPS) technique. The results indicate that the influence of Hf addition is significant on magnetic properties and thermal stabilities of the (PrNd)2Fe14B-type sintered magnets. It is shown that the sample with x = 0.5 at 300 K has much higher coercivity and remanent magnetization than those counterparts without Hf. The temperature coefficients of remanence (α) and coercivity (β) of the (Pr0.2Nd0.8)13Fe81-xB6Hfx magnets are improved significantly from -0.23 %/K, -0.57 %/K for the sample at x = 0 to -0.17 %/K, -0.49 %/K for the sample at x = 0.5 in the temperature range of 300-400 K. Furthermore, it is found out that the domain wall pinning mechanism is more likely responsible for enhancing the coercivity of the (Pr0.2Nd0.8)13Fe81-xB6Hfx magnets.

Determination of the effective anisotropy constant of CoFe2O4 nanoparticles through the T-dependence of the coercive field

NASA Astrophysics Data System (ADS)

Carvalho, M. H.; Lima, R. J. S.; Meneses, C. T.; Folly, W. S. D.; Sarmento, V. H. V.; Coelho, A. A.; Duque, J. G. S.

2016-03-01

We present a systematic study of the coercive field of CoFe2O4-SiO2 nanocomposites. The samples were prepared via the sol-gel method by using the Tetraethyl Orthosilicate as starting reagent. Results of X-ray diffraction, transmission electron microscopy, and X-ray fluorescence confirm the dispersion of the magnetic nanoparticles inside the silica matrix. In addition, the shift in the maximum of Zero-Field-Cooled curves observed by varying the weight ratio of CoFe2O4 nanoparticles to the precursor of silica is consistent with the increasing of average interparticle distances. Because our samples present a particle size distribution, we have used a generalized model which takes account such parameter to fit the experimental data of coercive field extracted from the magnetization curves as a function of applied field. Unlike most of the coercive field results reported in the literature for this material, the use of this model provided a successful description of the temperature dependence of the coercive field of CoFe2O4 nanoparticles in a wide temperature range. Surprisingly, we have observed the decreasing of the nanoparticles anisotropy constant in comparison to the bulk value expected for the material. We believe that this can be interpreted as due to both the migration of the Co2+ from octahedral to tetrahedral sites.

Structural, magnetic, and transport properties of Permalloy for spintronic experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nahrwold, Gesche; Scholtyssek, Jan M.; Motl-Ziegler, Sandra

2010-07-15

Permalloy (Ni{sub 80}Fe{sub 20}) is broadly used to prepare magnetic nanostructures for high-frequency experiments where the magnetization is either excited by electrical currents or magnetic fields. Detailed knowledge of the material properties is mandatory for thorough understanding its magnetization dynamics. In this work, thin Permalloy films are grown by dc-magnetron sputtering on heated substrates and by thermal evaporation with subsequent annealing. The specific resistance is determined by van der Pauw methods. Point-contact Andreev reflection is employed to determine the spin polarization of the films. The topography is imaged by atomic-force microscopy, and the magnetic microstructure by magnetic-force microscopy. Transmission-electron microscopymore » and transmission-electron diffraction are performed to determine atomic composition, crystal structure, and morphology. From ferromagnetic resonance absorption spectra the saturation magnetization, the anisotropy, and the Gilbert damping parameter are determined. Coercive fields and anisotropy are measured by magneto-optical Kerr magnetometry. The sum of the findings enables optimization of Permalloy for spintronic experiments.« less

Awaiting a Spark: How Three Chinese Territorial Disputes Could Jeopardize Peace in Asia

DTIC Science & Technology

2013-12-01

annexation.120 Therefore, 117 Koji Sonoda and Takashi Oshima, “U.S. Warns Against ‘Coercive Action...of Law, 1999. Sonoda, Koji , and Takashi Oshima. “U.S. Warns against ‘Coercive Action’ over Senkaku Issue.” The Asahi Shinbum, April 30, 2013. http

Initiation, Desistance, and Persistence of Men's Sexual Coercion

ERIC Educational Resources Information Center

Hall, Gordon C. Nagayama; Degarmo, David S.; Eap, Sopagna; Teten, Andra L.; Sue, Stanley

2006-01-01

Patterns of sexually coercive behavior were examined among 266 Asian American and 299 European American men over 1 year. Noncoercer (n = 358), desister (n = 120), initiator (n = 39), and persistent (n = 48) sexually coercive groups were identified. The strongest predictor of sexual coercion was past sexual coercion. Persistent sexual coercers were…

Electroplated Fe-Co-Ni films prepared in ammonium-chloride-based plating baths

NASA Astrophysics Data System (ADS)

Yanai, T.; Koda, K.; Kaji, J.; Aramaki, H.; Eguchi, K.; Takashima, K.; Nakano, M.; Fukunaga, H.

2018-05-01

We electroplated Fe-Co-Ni films in ammonium-chloride-based plating baths, and investigated the effect of the Co content on the magnetic properties and the structural ones of the as-plated films. The coercivity increased abruptly when the Co content become more than 60 at.%. As the rough surfaces were observed in the high Co content region, we considered that degradation of the surface is a factor of the abrupt increase in the coercivity. From the XRD analysis, we found that another factor of the abrupt increase is fcc-bcc phase transformation, and concluded that we need to keep the fcc structure to obtain Fe-Co-Ni films with low coercivity.

Coercivity degradation caused by inhomogeneous grain boundaries in sintered Nd-Fe-B permanent magnets

NASA Astrophysics Data System (ADS)

Chen, Hansheng; Yun, Fan; Qu, Jiangtao; Li, Yingfei; Cheng, Zhenxiang; Fang, Ruhao; Ye, Zhixiao; Ringer, Simon P.; Zheng, Rongkun

2018-05-01

Quantitative correlation between intrinsic coercivity and grain boundaries in three dimensions is critical to further improve the performance of sintered Nd-Fe-B permanent magnets. Here, we quantitatively reveal the local composition variation across and especially along grain boundaries using the powerful atomic-scale analysis technique known as atom probe tomography. We also estimate the saturation magnetization, magnetocrystalline anisotropy constant, and exchange stiffness of the grain boundaries on the basis of the experimentally determined structure and composition. Finally, using micromagnetic simulations, we quantify the intrinsic coercivity degradation caused by inhomogeneous grain boundaries. This approach can be applied to other magnetic materials for the analysis and optimization of magnetic properties.

Exploring Variations Within Situational Couple Violence and Comparisons With Coercive Controlling Violence and No Violence/No Control.

PubMed

Nielsen, Samantha K; Hardesty, Jennifer L; Raffaelli, Marcela

2016-02-01

We examined variations within situational couple violence among 23 divorcing mothers and compared them with mothers with coercive controlling violence and no violence/no control. Situational couple violence had great variability in frequency and severity of violence, fear, harassment, and protective strategies. In some cases, situational couple violence was frequent and severe and resembled coercive controlling violence in its consequences. The dynamics of fear and harassment in situational couple violence and in the divorce process in general warrant attention. Finally, mothers reported mental health symptoms that did not differ by group, which is likely due to the stresses of divorce. © The Author(s) 2015.

High-sensitivity GMR with low coercivity in top-IrMn spin-valves

NASA Astrophysics Data System (ADS)

Liu, H. R.; Qu, B. J.; Ren, T. L.; Liu, L. T.; Xie, H. L.; Li, C. X.; Ku, W. J.

2003-12-01

Top-IrMn spin-valves with a structure of Ta/NiFe/CoFe/Cu/CoFe/IrMn/Ta have been investigated. The spin-valves were deposited by high vacuum DC magnetron sputtering at room temperature. The magnetoresistance ratio reaches 9.12% at room temperature. The coercivity of the free layer and the exchange bias field is 1.04 and 180 Oe, respectively. The maximum sensitivity of the spin-valves is 8.36%/Oe. A reduction of 33.2% of the coercivity was obtained after a 2-min RIE process. Utilizing standard integrated circuit (IC) process, mass production of robust giant magnetoresistance sensors can be achieved with these spin-valve thin films.

High-coercivity FePt nanoparticle assemblies embedded in silica thin films.

PubMed

Yan, Q; Purkayastha, A; Singh, A P; Li, H; Li, A; Ramanujan, R V; Ramanath, G

2009-01-14

The ability to process assemblies using thin film techniques in a scalable fashion would be a key to transmuting the assemblies into manufacturable devices. Here, we embed FePt nanoparticle assemblies into a silica thin film by sol-gel processing. Annealing the thin film composite at 650 degrees C transforms the chemically disordered fcc FePt phase into the fct phase, yielding magnetic coercivity values H(c)>630 mT. The positional order of the particles is retained due to the protection offered by the silica host. Such films with assemblies of high-coercivity magnetic particles are attractive for realizing new types of ultra-high-density data storage devices and magneto-composites.

Initiation, desistance, and persistence of men's sexual coercion.

PubMed

Hall, Gordon C Nagayama; DeGarmo, David S; Eap, Sopagna; Teten, Andra L; Sue, Stanley

2006-08-01

Patterns of sexually coercive behavior were examined among 266 Asian American and 299 European American men over 1 year. Noncoercer (n = 358), desister (n = 120), initiator (n = 39), and persistent (n = 48) sexually coercive groups were identified. The strongest predictor of sexual coercion was past sexual coercion. Persistent sexual coercers were higher than the other groups in delinquency and hostile masculinity and were nearly twice as likely to engage in laboratory sexual harassment. Loss of face attenuated self-reported sexual coercion and laboratory sexual harassment risk among Asian Americans and attenuated only laboratory sexual harassment risk among European Americans. These findings suggest that the heterogeneity of sexually coercive behavior and ethnicity are important research and clinical considerations.

Validation of Acceptance of Coercive Sexual Behavior (ACSB). A Multimedia Measure of Adolescent Dating Attitudes

ERIC Educational Resources Information Center

Teten, Andra L.; Hall, Gordon C. Nagayama; Pacifici, Caesar

2005-01-01

The psychometric properties of the Acceptance of Coercive Sexual Behavior (ACSB), a multimedia measure of adolescent dating attitudes, were examined. The ACSB is an interactive instrument that uses video vignettes to depict adolescent dating situations. Analyses of the measure's factor structure, internal consistency, test-retest reliability, and…

Adolescent Resource Control: Associations with Physical and Relational Aggression, Prosocial and Withdrawn Behaviors, and Peer Regard

ERIC Educational Resources Information Center

Findley, Danielle; Ojanen, Tiina

2013-01-01

This study examined adolescent coercive and prosocial resource control strategies in relation to various indices of peer-reported behaviors and peer regard ("N" = 384; 12-14 years). Coercive control was uniquely positively related to physical and relational aggression and peer disliking, and negatively to prosocial behaviors when…

Coercion in the Evolution of Plant-Microbe Communication: A Perspective.

PubMed

Rowe, S L; Norman, J S; Friesen, M L

2018-06-06

Plants and microbes are dependent on chemical signals as a means of interkingdom communication. There are two predicted paths for the evolution of these signals. Ritualization is the oft-assumed pathway for the evolution of plant-microbe communication systems. In this process, chemical signals, which benefit both receiver and sender, evolve from chemical cues, which benefit only the receiver. However, plant-microbe signaling may evolve from coercive interactions as well, a process known as sensory manipulation. Here, we aim to highlight the prevalence of coercive interactions and discuss sensory manipulation in the context of plant-microbe interactions. We present two examples of stabilized coercion: microbial coercion of plants via the release of phytohormones and plant coercion of microbes via manipulation of quorum-sensing compounds. Furthermore, we provide an evolutionary framework for the emergence of signaling from coercive plant-microbe interactions through the process of sensory manipulation. We hope that researchers will recognize the relevance of coercive interactions in plant-microbe systems and consider sensory manipulation as a plausible evolutionary trajectory for the emergence of plant-microbe signaling.

What do potential jurors know about police interrogation techniques and false confessions?

PubMed

Leo, Richard A; Liu, Brittany

2009-01-01

Psychological police interrogation methods in America inevitably involve some level of pressure and persuasion to achieve their goal of eliciting confessions of guilt from custodial suspects. In this article, we surveyed potential jurors about their perceptions of a range of psychological interrogation techniques, the likelihood that such techniques would elicit a true confession from guilty suspects, and the likelihood that such techniques could elicit a false confession from innocent suspects. Participants recognized that these interrogation techniques may be psychologically coercive and may elicit true confessions, but believed that psychologically coercive interrogation techniques are not likely to elicit false confessions. The findings from this survey study indicate that potential jurors believe that false confessions are both counter- intuitive and unlikely, even in response to psychologically coercive interrogation techniques that have been shown to lead to false confessions from the innocent. This study provides empirical support for the idea that expert witnesses may helpfully inform jurors about the social science research on psychologically coercive interrogation methods and how and why such interrogation techniques can lead to false confessions. (c) 2009 John Wiley & Sons, Ltd.

Impact of parental emotional support and coercive control on adolescents' self-esteem and psychological distress: results of a four-year longitudinal study.

PubMed

Boudreault-Bouchard, Anne-Marie; Dion, Jacinthe; Hains, Jennifer; Vandermeerschen, Jill; Laberge, Luc; Perron, Michel

2013-08-01

This study aims at investigating the impact of parental practices on youths' adjustment. In all, 605 adolescents completed questionnaires at ages 14, 16 and 18. Self-esteem, psychological distress as well as parental emotional support and coercive control were measured. Analyses based on individual growth models revealed that self-esteem increased with age, but psychological distress remained stable over time. Boys reported higher levels of self-esteem and lower levels of psychological distress than girls. Maternal and paternal emotional support reinforced self-esteem over time. Maternal coercive control undermined self-esteem, but only at ages 16 and 18. Psychological distress decreased with parental emotional support but increased with parental coercive control at ages 14, 16 and 18. Overall, these results indicate that positive parental practices are related to youths' well-being. These findings support the importance of establishing intervention strategies designed to promote best practices among parents of teenagers to help them develop into well-adjusted adults. Copyright © 2013 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Stress remagnetization in pyrrhotite-calcite synthetic aggregates

NASA Astrophysics Data System (ADS)

Robion, Philippe; Borradaile, Graham J.

2001-01-01

Stress-induced remagnetization has been applied to multidomain pyrrhotite-calcite synthetic aggregates in a triaxial rig. Experimental deformation used 150MPa confining pressure, a constant strain rate of 10-5 s-1 and applied differential stresses of up to 70MPa. New components of magnetization, parallel to the direction of the pressure vessel field, were added to the pre-deformational magnetization. The intensity of remagnetization (M'-M0) increases with the intensity of the applied differential stress and affects the coercivity fraction below 15mT. Bulk shortening is less than 8 per cent, thus grain rotation cannot explain selective remagnetization of the low-coercivity fraction. Remagnetization is thus attributed to deformational viscous remanent magnetization (DVRM). It is observed that high-coercivity (>15mT) grains do not remagnetize. There is, however, slight progressive rotation of pre-deformational magnetization with increasing strain up to 8 per cent of bulk shortening. The lack of piezoremanent magnetization in the high-coercivity range may be due to defects introduced in pyrrhotite during sample preparation. Experiments using synthetic pyrrhotite, expected to show low dislocation densities, would be necessary to test this effect.

Adolescent mental health and subsequent parenting: a longitudinal birth cohort study

PubMed Central

Byford, M; Abbott, R A; Maughan, B; Richards, M; Kuh, D

2014-01-01

Background Adolescent mental health problems are associated with a range of adverse outcomes in adulthood but little is known about the effects on adult parenting practices. This study aimed to examine prospective associations between adolescent conduct and emotional problems and subsequent parenting behaviours in adulthood. Methods The study sample comprised 1110 members from the MRC National Survey of Health and Development. Prospective data were collected from teacher reports of conduct and emotional problems at age 13 and 15 years and adult outcome measures of parenting included intellectual environment, cognitive stimulation, coercive discipline, parental interest and parental aspiration. Results In regression models adjusted for the confounding effects of social background, cognition and education, adolescent conduct problems predicted coercive parenting behaviours in adulthood. The effects of adolescent emotional problems on the development of coercive discipline practices were explained by covariates. Likewise, the inability of parents who displayed conduct problems in adolescence to provide an intellectually stimulating home environment was fully explained by the adjustment for education. Conclusions Adolescents who exhibit conduct problems are more likely to develop coercive styles of parenting. PMID:24357583

Adolescent mental health and subsequent parenting: a longitudinal birth cohort study.

PubMed

Byford, M; Abbott, R A; Maughan, B; Kuh, D; Richards, M

2014-05-01

Adolescent mental health problems are associated with a range of adverse outcomes in adulthood but little is known about the effects on adult parenting practices. This study aimed to examine prospective associations between adolescent conduct and emotional problems and subsequent parenting behaviours in adulthood. The study sample comprised 1110 members from the MRC National Survey of Health and Development. Prospective data were collected from teacher reports of conduct and emotional problems at age 13 and 15 years and adult outcome measures of parenting included intellectual environment, cognitive stimulation, coercive discipline, parental interest and parental aspiration. In regression models adjusted for the confounding effects of social background, cognition and education, adolescent conduct problems predicted coercive parenting behaviours in adulthood. The effects of adolescent emotional problems on the development of coercive discipline practices were explained by covariates. Likewise, the inability of parents who displayed conduct problems in adolescence to provide an intellectually stimulating home environment was fully explained by the adjustment for education. Adolescents who exhibit conduct problems are more likely to develop coercive styles of parenting.

High coercivity in large exchange-bias Co/CoO-MgO nano-granular films

NASA Astrophysics Data System (ADS)

Ge, Chuan-Nan; Wan, Xian-Gang; Eric, Pellegrin; Hu, Zhi-Wei; Wen-I, Liang; Michael, Bruns; Zou, Wen-Qin; Du, You-Wei

2015-03-01

We present a detailed study on the magnetic coercivity of Co/CoO-MgO core-shell systems, which exhibits a large exchange bias due to an increase of the uncompensated spin density at the interface between the CoO shell and the metallic Co core by replacing Co by Mg within the CoO shell. We find a large magnetic coercivity of 7120 Oe around the electrical percolation threshold of the Co/CoO core/shell particles, while samples with a smaller or larger Co metal volume fraction show a considerably smaller coercivity. Thus, this study may lead to a route to improving the magnetic properties of artificial magnetic material in view of potential applications. Project supported by the National Basic Research Program of China (Grant No. 2012CB932304), the National Natural Science Foundation of China (Grant Nos. U1232210, 91122035, 11174124, and 11374137), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 14KJB140003), and the Priority Academic Program Development of Jiangsu Higher Education Institutions, China.

Using the ferroelectric/ferroelastic effect at cryogenic temperatures for set-and-hold actuation

NASA Astrophysics Data System (ADS)

Steeves, J. B.; Golinveaux, F. S.; Lynch, C. S.

2018-06-01

The ferroelectric and ferroelastic properties of lead-zirconate-titanate (PZT) based stack actuators have been characterized at temperatures down to 25 K and under various levels of constant compressive stress. Experiments indicate that the coercive field and magnitude of strain at the coercive field display an inverse relationship with temperature. A factor of 5.5 increase in coercive field, and a factor of 4.3 increase in strain is observed at 25 K in comparison to the room-temperature conditions. This information was used to induce non-180° domain wall motion in the material through the application of electric fields at or near the coercive field. The change in remanent strain accompanying these effects was shown to increase in magnitude as temperature decreased, reaching values of 2000 ppm at 25 K. This behavior was also shown to be temporally stable even under compressive loads. Additionally, it was demonstrated that the material can be returned to its original strain state through a repolarizing electric field. This switchable behavior could be exploited for future set-and-hold type actuators operating at cryogenic temperatures.

[Comparison of Aggressive Behavior, Compulsory Medication and Absconding Behavior Between Open and Closed door Policy in an Acute Psychiatric Ward].

PubMed

Cibis, Mara-Lena; Wackerhagen, Carolin; Müller, Sabine; Lang, Undine E; Schmidt, Yvonne; Heinz, Andreas

2017-04-01

Objective According to legal requirements coercive treatment must be limited to acts necessary for the protection of patients and cannot be used for institutional interests. Here, we aimed to test the hypothesis that opening psychiatric wards can reduce the number of aggressive assaults and of coercive treatment without increasing absconding rates. Methods Numbers of absconding, coercive medication, fixation and special security actions were collected retrospectively and compared between phases of closed (N total = 409; N legally committed = 64) and 90 % of daytime opened (N total = 571; N legally committed = 99) doors in an acute psychiatric ward. Results During the phase of opened doors we observed significantly reduced aggressive assaults (p < 0,001) and coercive medication (p = 0,006) compared to the closed setting, while the absconding rate did not change (p = 0,20). Limitation Given the retrospective non-experimental design, no causal interpretations can be drawn. Conclusion The results suggest that open door is associated with reduction of aggressive assaults and coercive medication without increasing absconding rates. This speaks for a stronger implementation of open door policies in acute wards in order to preserve human rights in psychiatry. To collect more robust evidence for this thesis, longer phases should be monitored and moderating variables such as atmosphere and social cohesion should be assessed. © Georg Thieme Verlag KG Stuttgart · New York.

Synergetic Effect of Dy2O3 and Ca Co-Dopants towards Enhanced Coercivity of Rare Earth Abundant RE-Fe-B Magnets.

PubMed

Li, Yingfei; Tian, Na; Fan, Xiaodong; You, Caiyin; Pei, Wenli; Cheng, Zhenxiang

2017-12-13

Low coercivity is the main disadvantage of RE-Fe-B permanent magnets containing highly abundant rare earths (RE: La, Ce) from the application point of view, even though they exhibit many cost and resource advantages. In this work, an industrial mixed rare earth alloy (RE 100  = La 30.6 Ce 50.2 Pr 6.4 Nd 12.8 ) with a high amount of the more abundant elements was adopted to fabricate RE-Fe-B permanent magnets by means of mechanical alloying accompanied by post-annealing. A synergetic effect towards enhancing the coercivity was observed after co-doping with Dy 2 O 3 and Ca, with the coercivity increasing from 2.44 kOe to 11.43 kOe for co-dopant percentages of 7 wt.% Dy 2 O 3  + 2.3 wt.% Ca. Through analysis of the phase constituents and microstructure, it was determined that part of the Dy atoms entered the matrix of RE 2 Fe 14 B phase to enhance the magnetocrystalline anisotropy; due to the reductive effect of Ca on Dy 2 O 3 , nanocrystals of Dy-rich RE 2 Fe 14 B were present throughout the matrix, which could increase the resistance to domain wall movement. These are the dominant factors behind the improvement of the coercivity of the RE-Fe-B magnets with highly abundant RE elements.

Magnetization mechanisms in ordered arrays of polycrystalline Fe100-xCox nanowires

NASA Astrophysics Data System (ADS)

Viqueira, M. S.; Bajales, N.; Urreta, S. E.; Bercoff, P. G.

2015-05-01

Magnetization reversal processes and coercivity mechanisms in polycrystalline Fe100-xCox nanowire arrays, resulting from an AC electrodeposition process, are investigated. The array coercivity is described on the basis of polarization reversal mechanisms operating in individual wires, under the effect of inter-wire dipolar interactions described by a mean field approximation. For individual wires, a reversal mechanism involving the nucleation and further expansion of domain-wall like spin configuration is considered. The wires have a mean grain size larger than both the nanowire diameter and the exchange length, so localized and non-cooperative nucleation modes are considered. As the Co content increases, the alloy saturation polarization gradually decreases, but the coercive field and the relative remanence of the arrays increase, indicating that they are not controlled by the shape anisotropy in all the composition range. The coercive field dependence on the angle between the applied field and the wire long axis is not well described by reversal mechanisms involving nucleation and further displacement of neither vortex nor transverse ideal domain walls. On the contrary, the angular dependence of the coercive field observed at room temperature is well predicted by a model considering nucleation of inverse domains by localized curling, in regions smaller than the grain size, exhibiting quite small aspect ratios as compared to those of the entire nanowire. In arrays with higher Co contents, a transition from an initial (small angle) localized curling nucleation mechanism to another one, involving localized coherent rotation is observed at about π/4.

Risk factors of coercion among psychiatric inpatients: a nationwide register-based cohort study.

PubMed

Thomsen, Christoffer; Starkopf, Liis; Hastrup, Lene Halling; Andersen, Per Kragh; Nordentoft, Merete; Benros, Michael Eriksen

2017-08-01

Reducing the use of coercion among patients with mental disorders has long been a political priority. However, risk factors for coercive measures have primarily been investigated in smaller studies. To reduce the use of coercion, it is crucial to identify people at risk which we aim to do in this first large-scale study. A cohort study was conducted among all psychiatric inpatients in Denmark, following 112,233 individuals during 1999-2014. Data from Danish registers were analysed using logistic regression for repeated measures. 24,594 inpatients were exposed to a coercive measure (21.9%). Clinical characteristics were the foremost predictors of coercion and patients with organic mental disorder had the highest increased risk of being subjected to a coercive measure (OR = 5.56; 95% CI = 5.04, 6.14). The risk of coercion was the highest in the first admission and decreased with the number of admissions (all p < 0.001). The following socioeconomic variables were associated with an increased risk of coercion: male sex, unemployment, lower social class and immigrants from low and middle income countries (all p < 0.001). Early retirement and social relations, such as being married and having children, reduced the risk of being subjected to coercive measure (all p < 0.05). From our nationwide data, we identified a broad range of risk factors associated with coercive measures. Our findings can assist researchers in identifying patients at risk of coercion and thereby help targeting new coercion reduction programs.

High magnetic coercivity of FePt-Ag/MgO granular nanolayers

NASA Astrophysics Data System (ADS)

Roghani, R.; Sebt, S. A.; Khajehnezhad, A.

2018-06-01

L10-FePt ferromagnetic nanoparticles have a hight coercivity of Tesla order. Thus, these nanoparticles, with size of 10 to 15 nm and uniform surface distribution, are suitable in magnetic data storage technology with density of more than 1GB. In order to improve structural and magnetic properties of FePt nanoparticles, some elements and combinations have been added to compound. In this research, we show that due to the presence of the Ag, the phase transition temperature of FePt from fcc to L10-fct phase decreases. The presence of Ag as an additive in FePt-Ag nanocomposite, increases the magnetic coercivity. This nanocomposite, with 10% Ag, was deposited by magnetron sputtering on the MgO heat layer. VSM results of 10 nm nanoparticles show that coercivity has increased up to 1.4 T. XRD and FESEM results confirm that the size of the L10-FePt nanoparticles are 10 nm and their surface distribution are uniform. Ag gradually form nano scale clusters with separate lattice and FePt-Ag nanocomposite appears. The result of this process is emptiness of Ag position in FePt-fcc lattice. So, the mobility of Fe and Pt atoms in this lattice increases and it can be possible for them to move in lower temperature. This mechanism explain the effect of Ag on decreasing the transition temperature to fct-L10 phase, and hight coercivity of FePt nanoparticles.

Magnetic properties of a stainless steel irradiated with 6 MeV Xe ions

NASA Astrophysics Data System (ADS)

Xu, Chaoliang; Liu, Xiangbing; Qian, Wangjie; Li, Yuanfei

2017-11-01

Specimens of austenitic stainless steel were irradiated with 6 MeV Xe ions at room temperature to 2, 7, 15 and 25 dpa. The vibrating sample magnetometer (VSM), grazing incidence X-ray diffraction (GIXRD) and positron annihilation lifetime spectroscopy (PLS) were carried out to analysis the magnetic properties and microstructural variations. The magnetic hysteresis loops indicated that higher irradiation damage causes more significant magnetization phenomenon. The equivalent saturated magnetization Mes and coercive force Hc were obtained from magnetic hysteresis loops. It is indicated that the Mes increases with irradiation damage. While Hc increases first to 2 dpa and then decreases continuously with irradiation damage. The different contributions of irradiation defects and ferrite precipitates on Mes and Hc can explain these phenomena.

Magnetic properties of Fe-doped NiO nanoparticles

NASA Astrophysics Data System (ADS)

Kurokawa, A.; Sakai, N.; Zhu, L.; Takeuchi, H.; Yano, S.; Yanoh, T.; Onuma, K.; Kondo, T.; Miike, K.; Miyasaka, T.; Ichiyanagi, Y.

2013-08-01

Ni1- x Fe x O ( x = 0, 0.05, 0.1) nanoparticles with several nanometers encapsulated with amorphous SiO2 were prepared by our novel preparation method. A NiO single phase structure was confirmed using the X-ray diffraction measurements. It is considered that Ni ions are replaced by Fe ions because it is observed that the lattice constant decreases. The temperature dependence behavior of the magnetization revealed that the blocking temperature, T B , shifted from 17 to 57 K as the amount of Fe ions increased, and that below T B , ferromagnetic behaviors were exhibited. The coercive force, H C , increased from 0.8 to 1.5 kOe as the amount of Fe ions increased.

Magnetic Properties of Hard Magnetic Alloy Fe - 28% Cr - 13.4% Co - 2% Mo - 0.5% Si

NASA Astrophysics Data System (ADS)

Vompe, T. A.; Milyaev, I. M.; Yusupov, V. S.

2017-01-01

The method of regression analysis is used to obtain equations describing the dependences of magnetic hysteresis properties of magnetically hard powder alloy Fe - 28% Cr - 13.4% Co - 2% Mo - 0.5% Si on regimes of thermomagnetic treatment (the temperatures of the start of the treatment and the rates of cooling in magnetic field). The determined treatment modes make it possible to obtain in an alloy with a coercive force H c up to 40 kA/m, a residual induction B r up to 1.2 T, and a maximum energy product ( BH)max up to 25 kJ/m3. The alloy may find application in the production of rotors of synchronous hysteresis-reluctance motors.

Micromagnetism in a planar system with a random magnetic anisotropy and two-dimensional magnetic correlations

NASA Astrophysics Data System (ADS)

Komogortsev, S. V.; Fel'k, V. A.; Iskhakov, R. S.; Shadrina, G. V.

2017-08-01

The hysteresis loops and the micromagnetic structure of a ferromagnetic nanolayer with a randomly oriented local easy magnetization axis and two-dimensional magnetization correlations are studied using a micromagnetic simulation. The properties and the micromagnetic structure of the nanolayer are determined by the competition between the anisotropy and exchange energies and by the dipole-dipole interaction energy. The magnetic microstructure can be described as an ensemble of stochastic magnetic domains and topological magnetization defects. Dipole-dipole interaction suppresses the formation of topological magnetization defects. The topological defects in the magnetic microstructure can cause a sharper change in the coercive force with the crystallite size than that predicted by the random magnetic anisotropy model.

Untangling Magmatic Processes and Hydrothermal Alteration of in situ Superfast Spreading Ocean Crust at ODP/IODP Site 1256 with Fuzzy c-means Cluster Analysis of Rock Magnetic Properties

NASA Astrophysics Data System (ADS)

Dekkers, M. J.; Heslop, D.; Herrero-Bervera, E.; Acton, G.; Krasa, D.

2014-12-01

Ocean Drilling Program (ODP)/Integrated ODP (IODP) Hole 1256D (6.44.1' N, 91.56.1' W) on the Cocos Plate occurs in 15.2 Ma oceanic crust generated by superfast seafloor spreading. Presently, it is the only drill hole that has sampled all three oceanic crust layers in a tectonically undisturbed setting. Here we interpret down-hole trends in several rock-magnetic parameters with fuzzy c-means cluster analysis, a multivariate statistical technique. The parameters include the magnetization ratio, the coercivity ratio, the coercive force, the low-field susceptibility, and the Curie temperature. By their combined, multivariate, analysis the effects of magmatic and hydrothermal processes can be evaluated. The optimal number of clusters - a key point in the analysis because there is no a priori information on this - was determined through a combination of approaches: by calculation of several cluster validity indices, by testing for coherent cluster distributions on non-linear-map plots, and importantly by testing for stability of the cluster solution from all possible starting points. Here, we consider a solution robust if the cluster allocation is independent of the starting configuration. The five-cluster solution appeared to be robust. Three clusters are distinguished in the extrusive segment of the Hole that express increasing hydrothermal alteration of the lavas. The sheeted dike and gabbro portions are characterized by two clusters, both with higher coercivities than in lava samples. Extensive alteration, however, can obliterate magnetic property differences between lavas, dikes, and gabbros. The imprint of thermochemical alteration on the iron-titanium oxides is only partially related to the porosity of the rocks. All clusters display rock magnetic characteristics in line with a stable NRM. This implies that the entire sampled sequence of ocean crust can contribute to marine magnetic anomalies. Determination of the absolute paleointensity with thermal techniques is not straightforward because of the propensity of oxyexsolution during laboratory heating and/or the presence of intergrowths. The upper part of the extrusive sequence, the granoblastic portion of the dikes, and moderately altered gabbros may contain a comparatively uncontaminated thermoremanent magnetization.

From Antisocial Behavior to Violence: A Model for the Amplifying Role of Coercive Joining in Adolescent Friendships

ERIC Educational Resources Information Center

Van Ryzin, Mark J.; Dishion, Thomas J.

2013-01-01

Background: Aggression is one of the more stable characteristics of child and adolescent development, and violent behavior in early adulthood is often foreshadowed by aggressive behavior in childhood and early adolescence. Considerable evidence has linked coercive family interactions to aggressive behavior in childhood, but less research has been…

Gender Differences in Patterns of Experienced Sexual Coercion and Associated Vulnerability Factors among Young People in the Netherlands

ERIC Educational Resources Information Center

Kuyper, Lisette; de Wit, John; Smolenski, Derek; Adam, Philippe; Woertman, Liesbeth; van Berlo, Willy

2013-01-01

The development of effective policies and programs to prevent sexual coercion among young people requires thorough understanding of the diversity of coercive sexual experiences, patterns in such types of experiences, and similarities and differences between subgroups, especially by gender, in patterns of coercive sexual experiences and…

Mental health, coercion and family caregiving: issues from the international literature.

PubMed

Rugkåsa, Jorun; Canvin, Krysia

2017-08-01

This article summarises current knowledge about two aspects of family care for people with mental illness: potentially pressurising or coercive aspects of family life; and family carers' experiences of being involved in coercive service interventions. There is a paucity of studies on these topics, especially outside Europe, North America and Australasia, and further research is recommended.

Sex-Symmetric Effects of Coercive Behaviors on Mental Health? Not Exactly

ERIC Educational Resources Information Center

Prospero, Moises

2009-01-01

The present study tested a section of the model of coercion in intimate partner violence (IPV) by investigating the relationships among coercion, IPV and mental health symptoms. The study's sample consisted of 573 culturally diverse university students (age M = 21.4) who completed a survey that measured past IPV victimization, coercive behaviors,…

Economic Crisis, Accountability, and the State's Coercive Assault on Public Education in the USA

ERIC Educational Resources Information Center

Lipman, Pauline

2013-01-01

This article examines education accountability as a mechanism of coercive neoliberal urban governance in the USA. Drawing on Gramscian theory of the "integral state" as the dialectical synthesis of coercion, consent, and resistance, the author argues that as the crisis gives the state less room to win consent, it intensifies coercion as…

Simulation of alnico coercivity

DOE PAGES

Ke, Liqin; Skomski, Ralph; Hoffmann, Todd D.; ...

2017-07-10

Micromagnetic simulations of alnico show substantial deviations from Stoner-Wohlfarth behavior due to the unique size and spatial distribution of the rod-like Fe-Co phase formed during spinodal decomposition in an external magnetic field. Furthemore, the maximum coercivity is limited by single-rod effects, especially deviations from ellipsoidal shape, and by interactions between the rods. In both the exchange interaction between connected rods and magnetostatic we consider the interaction between rods, and the results of our calculations show good agreement with recent experiments. Unlike systems dominated by magnetocrystalline anisotropy, coercivity in alnico is highly dependent on size, shape, and geometric distribution of themore » Fe-Co phase, all factors that can be tuned with appropriate chemistry and thermal-magnetic annealing.« less

Lies and coercion: why psychiatrists should not participate in police and intelligence interrogations.

PubMed

Janofsky, Jeffrey S

2006-01-01

Police interrogators routinely use deceptive techniques to obtain confessions from criminal suspects. The United States Executive Branch has attempted to justify coercive interrogation techniques in which physical or mental pain and suffering may be used during intelligence interrogations of persons labeled unlawful combatants. It may be appropriate for law enforcement, military, or intelligence personnel who are not physicians to use such techniques. However, forensic psychiatry ethical practice requires honesty, striving for objectivity, and respect for persons. Deceptive and coercive interrogation techniques violate these moral values. When a psychiatrist directly uses, works with others who use, or trains others to use deceptive or coercive techniques to obtain information in police, military, or intelligence interrogations, the psychiatrist breaches basic principles of ethics.

Electric field control of magnetic properties in FeRh/PMN-PT heterostructures

NASA Astrophysics Data System (ADS)

Xie, Yali; Zhan, Qingfeng; Shang, Tian; Yang, Huali; Liu, Yiwei; Wang, Baomin; Li, Run-Wei

2018-05-01

We investigated electric control of magnetic properties in FeRh/PMN-PT heterostructures. An electric field of 1 kV/cm applied on the PMN-PT substrate could increase the coercivity of FeRh film from 60 to 161 Oe at 360 K where the FeRh antiferromagnetic to ferromagnetic phase transition occurs. The electric field dependent coercive field reveals a butterfly shape, indicating a strain-mediated magnetoelectric coupling across the FeRh/PMN-PT interface. However, the uniaxial magnetic anisotropy of FeRh is almost unchanged with the applied electric field on the PMN-PT substrate, which suggests the change of coercivity in FeRh films is mainly due to the shift of the magnetic transition temperature under the electric field.

Magnetic properties of sputtered Permalloy/molybdenum multilayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romera, M.; Ciudad, D.; Maicas, M.

2011-10-15

In this work, we report the magnetic properties of sputtered Permalloy (Py: Ni{sub 80}Fe{sub 20})/molybdenum (Mo) multilayer thin films. We show that it is possible to maintain a low coercivity and a high permeability in thick sputtered Py films when reducing the out-of-plane component of the anisotropy by inserting thin film spacers of a non-magnetic material like Mo. For these kind of multilayers, we have found coercivities which are close to those for single layer films with no out-of-plane anisotropy. The coercivity is also dependent on the number of layers exhibiting a minimum value when each single Py layer hasmore » a thickness close to the transition thickness between Neel and Bloch domain walls.« less

Phase formation and magnetic hardening mechanism of TbCu7 type Sm-Fe-N powders

NASA Astrophysics Data System (ADS)

Lu, Cifu; Hong, Xiufeng; Ding, Zhiyi; Shi, Jiaxing; Bao, Xiaoqian; Gao, Xuexu; Zhu, Jie

2018-06-01

(Sm0.7Zr0.3)x(Fe0.9Co0.1)100-x (x = 9.1,10.7,10.9,12.6,13.4) alloys almost consist of TbCu7 type phase were prepared by rapid quenching technique and annealing. A series of TbCu7 type Sm-Zr-Fe-Co-N magnetically hard powders were prepared through nitrogenization of the alloys. With (Sm0.7Zr0.3) content increases, the coercivity increased but magnetization decreases. TbCu7-type nitride powder with coercivity of 10.8 kOe can be obtained when x = 13.6. The initial magnetization curves of the powders indicate that the coercivity should be controlled by pinning mechanism.

Magnetic Hysteresis of Deep-Sea Sediments in Korea Deep Ocean Study(KODOS) Area, NE Pacific

NASA Astrophysics Data System (ADS)

Kim, K.; Park, C.; Yoo, C.

2001-12-01

The KODOS area within the Clarion-Clipperton fracture zone (C-C zone) is surrounded by the Hawaiian and Line Island Ridges to the west and the central American continent to the east. Topography of the seafloor consists of flat-topped abyssal hills and adjacent abyssal troughs, both of which run parallel in N-S direction. Sediments from the study area consist mainly of biogenic sediments. Latitudinal zonation of sedimentary facies was caused by the accumulation of biogenic materials associated with the equatorial current system and movement of the Pacific plate toward the north or northwest. The KODOS area belongs to the latitudinal transition zone having depositional characteristics between non-fossiliferous pelagic clay-dominated zone and calcareous sediment-dominated zone. The box core sediments of the KODOS area are analyzed in an attempt to obtain magnetic hysteresis information and to elucidate the relationship between hysteresis property and lithological facies. Variations in magnetic hysteresis parameters with unit layers reflect the magnetic grain-size and concentrations within the sediments. The ratios of remanant coercivity/coercive force (Hcr/Hc) and saturation remnance/saturation magnetization (Mrs/Ms) indicate that coarse magnetic grains are mainly distributed in dark brown sediments (lower part of the sediment core samples) reflecting high Hcr/Hc and low Mrs/Ms ratios. These results are mainly caused by dissolution differences with core depth. From the plotting of the ratios of hyteresis parameters, it is indicated that magnetic minerals in cubic samples are in pseudo-single domain (PSD) state.

Coercivity of die upset NdFeB magnets: A strong pinning model

NASA Astrophysics Data System (ADS)

Pinkerton, F. E.; Fuerst, C. D.

1990-09-01

We show that the temperature dependence of the intrinsic coercivity Hci( T) between 5 and 600 K in a die-upset NdFeB magnet is in good agreement with a model for strong domain wall pinning by a random array of pinning sites proposed by Gaunt [P. Gaunt, Phil. Mag. B48 (1983) 261]. The model includes both the temperature dependence of the intrinsic magnetic properties of the Nd 2Fe 14B phase and the effects of thermal activation of domain walls over the pinning barrier. The pinning sites are modeled as nonmagnetic planar inhomogeneities at the boundaries aetween platelet-shaped Nd 2Fe 14B grains. We develop an expression for the maximum pinning force per site, f, and derive the model prediction that (H ci/γH A) {1}/{2} varies linearly with (T/γ) {2}/{3}, where HA and γ are the magnetocrystalline anisotropy and the domain wall energy per unit area of the Nd 2Fe 14B phase, respectively. The model is in good agreement with the observed Hci values over a broad temperature range from 200 to 477 K. Deviations from the model below 200 K are an artifact of the axial-to-conical spin reorientation in Nd 2Fe 14B at low temperature. Deviations at high temperature most likely occur because the strong pinning model is no longer valid close to the Curie temperature (585 K).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ray, Sekhar C., E-mail: raysc@unisa.ac.za; Mishra, D. K.; Department of Physics, Institute of Technical Research and Education, Siksha ‘O’ Anusandhan University, Khandagiri Square, Bhubaneswar 751030, Odisha

The electronic structures and magnetic properties of graphene nanoflakes (GNFs) exposed to an organo-silane precursor [tetra-methyl-silane, Si(CH{sub 3}){sub 4}] were studied using atomic force microscopy, electron field emission (EFE), x-ray photoelectron spectroscopy (XPS), and magnetization. The result of XPS indicates that silyl radical based strong covalent bonds were formed in GNFs, which induced local structural relaxations and enhanced sp{sup 3} hybridization. The EFE measurements show an increase in the turn-on electric field from 9.8 V/μm for pure GNFs to 26.3 V/μm for GNFs:Si having highest Si/(Si + C) ratio ( ≅ 0.35) that also suggests an enhancement of the non-metallic sp{sup 3} bonding in the GNFsmore » matrix. Magnetic studies show that the saturation magnetization (Ms) is decreased from 172.53 × 10{sup −6} emu/g for pure GNFs to 13.00 × 10{sup −6} emu/g for GNFs:Si with the highest Si/(Si + C) ratio 0.35, but on the other side, the coercivity (Hc) increases from 66 to 149 Oe due to conversion of sp{sup 2} → sp{sup 3}-hybridization along with the formation of SiC and Si-O bonding in GNFs. The decrease in saturation magnetization and increase in coercivity (Hc) in GNFs on Si-functionalization are another routes to tailor the magnetic properties of graphene materials for magnetic device applications.« less

Faster modified protocol for first order reversal curve measurements

NASA Astrophysics Data System (ADS)

De Biasi, Emilio

2017-10-01

In this work we present a faster modified protocol for first order reversal curve (FORC) measurements. The main idea of this procedure is to use the information of the ascending and descending branches constructed through successive sweeps of magnetic field. The new method reduces the number of field sweeps to almost one half as compared to the traditional method. The length of each branch is reduced faster than in the usual FORC protocol. The new method implies not only a new measurement protocol but also a new recipe for the previous treatment of the data. After of these pre-processing, the FORC diagram can be obtained by the conventional methods. In the present work we show that the new FORC procedure leads to results identical to the conventional method if the system under study follows the Stoner-Wohlfarth model with interactions that do not depend of the magnetic state (up or down) of the entities, as in the Preisach model. More specifically, if the coercive and interactions fields are not correlated, and the hysteresis loops have a square shape. Some numerical examples show the comparison between the usual FORC procedure and the propose one. We also discuss that it is possible to find some differences in the case of real systems, due to the magnetic interactions. There is no reason to prefer one FORC method over the other from the point of view of the information to be obtained. On the contrary, the use of both methods could open doors for a more accurate and deep analysis.

Childhood Sexual Abuse, Attachments in Childhood and Adulthood, and Coercive Sexual Behaviors in Community Males.

PubMed

Langton, Calvin M; Murad, Zuwaina; Humbert, Bianca

2017-04-01

Associations between self-reported coercive sexual behavior against adult females, childhood sexual abuse (CSA), and child-parent attachment styles, as well as attachment with adult romantic partners, were examined among 176 adult community males. Attachment style with each parent and with romantic partners was also investigated as a potential moderator. Using hierarchical multiple regression analysis, avoidant attachment with mothers in childhood (and also with fathers, in a second model) accounted for a significant amount of the variance in coercive sexual behavior controlling for scores on anxious ambivalent and disorganized/disoriented attachment scales, as predicted. Similarly, in a third model, avoidance attachment in adulthood was a significant predictor of coercive sexual behavior controlling for scores on the anxiety attachment in adulthood scale. These main effects for avoidant and avoidance attachment were not statistically significant when CSA and control variables (other types of childhood adversity, aggression, antisociality, and response bias) were added in each of the models. But the interaction between scales for CSA and avoidance attachment in adulthood was significant, demonstrating incremental validity in a final step, consistent with a hypothesized moderating function for attachment in adulthood. The correlation between CSA and coercive sexual behavior was .60 for those with the highest third of avoidance attachment scores (i.e., the most insecurely attached on this scale), .24 for those with scores in the middle range on the scale, and .01 for those with the lowest third of avoidance attachment scores (i.e., the most securely attached). Implications for study design and theory were discussed.

Effects of Video Feedback on Early Coercive Parent–Child Interactions: The Intervening Role of Caregivers’ Relational Schemas

PubMed Central

Smith, Justin D.; Dishion, Thomas J.; Moore, Kevin J.; Shaw, Daniel S.; Wilson, Melvin N.

2013-01-01

Objective We examined the effect of adding a video feedback intervention component to the assessment feedback session of the Family Check-Up intervention (FCU; Dishion & Stormshak, 2007). We hypothesized that the addition of video feedback procedures during the FCU feedback at child age 2 would have a positive effect on caregivers’ negative relational schemas of their child, which in turn would mediate reductions in observed coercive caregiver-child interactions assessed at age 5. Method We observed the caregiver-child interaction videotapes of 79 high-risk families with toddlers exhibiting clinically significant problem behaviors. A quasi-random sample of families were provided with direct feedback on their interactions during the feedback session of the FCU protocol. Results Path analysis indicated that reviewing and engaging in feedback about videotaped age-2 assessment predicted reduced caregivers’ negative relational schemas of the child at age 3, which acted as an intervening variable on the reduction of observed parent–child coercive interactions recorded at age 5. Video feedback predicted improved family functioning over and above level of engagement in the FCU in subsequent years, indicating the important incremental contribution of using video feedback procedures in early family-based preventive interventions for problem behaviors. Conclusions Supportive video feedback on coercive family dynamics is an important strategy for promoting caregiver motivation to reduce negative attributions toward the child, which fuel coercive interactions. Our study also contributes to the clinical and research literature concerning coercion theory and effective intervention strategies by identifying a potential mechanism of change. PMID:23534831

Negative Relational Schemas Predict the Trajectory of Coercive Dynamics During Early Childhood

PubMed Central

Smith, Justin D.; Dishion, Thomas J.; Shaw, Daniel S.; Wilson, Melvin N.

2014-01-01

Coercive family processes are germane to the development of problem behaviors in early childhood, yet the cognitive and affective underpinnings are not well understood. We hypothesized that one antecedent of early coercive interactions is the caregiver’s implicit affective attitudes toward the child, which in this article are termed relational schemas. Relational schemas have previously been linked to coercion and problem behaviors, but there has yet to be an examination of the association between relational schemas and trajectories of coercion during early childhood. We examined 731 indigent caregiver-child dyads (49% female children) from a randomized intervention trial of the Family Check-Up. Predominantly biological mothers participated. A speech sample was used to assess relational schemas at age 2. Coercive interactions were assessed observationally each year between ages 2 and 4. Caregiver and teacher reports of children’s oppositional and aggressive behaviors were collected at age 7.5 and 8.5. Path analysis revealed that negative relational schemas were associated with less steep declines in coercion during this period, which in turn were predictive of ratings of oppositional and aggressive behaviors at age 7.5/8.5 after controlling for baseline levels, positive relational schemas, child gender, ethnicity, and cumulative risk. Intervention condition assignment did not moderate this relationship, suggesting the results represent a naturally occurring process. Given the link between persistent early coercion and later deleterious outcomes, relational schemas that maintain and amplify coercive dynamics represent a potential target for early intervention programs designed to improve parent–child relationships. PMID:25208813

Transforming Parent-Child Interaction in Family Routines: Longitudinal Analysis with Families of Children with Developmental Disabilities.

PubMed

Lucyshyn, Joseph M; Fossett, Brenda; Bakeman, Roger; Cheremshynski, Christy; Miller, Lynn; Lohrmann, Sharon; Binnendyk, Lauren; Khan, Sophia; Chinn, Stephen; Kwon, Samantha; Irvin, Larry K

2015-12-01

The efficacy and consequential validity of an ecological approach to behavioral intervention with families of children with developmental disabilities was examined. The approach aimed to transform coercive into constructive parent-child interaction in family routines. Ten families participated, including 10 mothers and fathers and 10 children 3-8 years old with developmental disabilities. Thirty-six family routines were selected (2 to 4 per family). Dependent measures included child problem behavior, routine steps completed, and coercive and constructive parent-child interaction. For each family, a single case, multiple baseline design was employed with three phases: baseline, intervention, and follow-up. Visual analysis evaluated the functional relation between intervention and improvements in child behavior and routine participation. Nonparametric tests across families evaluated the statistical significance of these improvements. Sequential analyses within families and univariate analyses across families examined changes from baseline to intervention in the percentage and odds ratio of coercive and constructive parent-child interaction. Multiple baseline results documented functional or basic effects for 8 of 10 families. Nonparametric tests showed these changes to be significant. Follow-up showed durability at 11 to 24 months postintervention. Sequential analyses documented the transformation of coercive into constructive processes for 9 of 10 families. Univariate analyses across families showed significant improvements in 2- and 4-step coercive and constructive processes but not in odds ratio. Results offer evidence of the efficacy of the approach and consequential validity of the ecological unit of analysis, parent-child interaction in family routines. Future studies should improve efficiency, and outcomes for families experiencing family systems challenges.

Magnetic studies of SiO2 coated CoFe2O4 nanoparticles

NASA Astrophysics Data System (ADS)

Limaye, Mukta V.; Singh, Shashi B.; Das, Raja; Poddar, Pankaj; Abyaneh, Majid K.; Kulkarni, Sulabha K.

2017-11-01

Oleic acid capped CoFe2O4 nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO2. We have used chemical synthesis method to obtain SiO2 coated CoFe2O4 nanoparticles with different weight percentages of CoFe2O4 in SiO2 (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe2O4 nanoparticles is retained after silica coating process. The complete coating of SiO2 on CoFe2O4 nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO2 coated CoFe2O4 particles remains more or less unaffected as in CoFe2O4 nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe2O4 and SiO2 coated 1.5 wt.% CoFe2O4 samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe2O4 nanoparticles.

Industrial responses to constrained OSHA regulation. Occupational Safety and Health Administration.

PubMed

Pedersen, D H

2000-01-01

As part of the effort to reduce the size and economic impact of the federal establishment, congressional conservatives are proposing legislation to restrict the regulatory activity of the Occupational Safety and Health Administration (OSHA). These proposals push OSHA toward a purely consultative role, at a corresponding cost in direct regulatory capability. The Clinton administration's reinvention of government initiative is also moving OSHA toward a consultative role based on a strategy of cooperative compliance or industry self-regulation with a strong coercive foundation. Since both camps appear to agree that self-regulation can assure a safe and healthy workplace, the remaining debate concerns the extent to which coercive regulation is still needed. National survey data on the industrial provision of occupational safety and health services in the manufacturing sector were used to measure changes in industrial safety and health activity between 1972-74 and 1981-83. In conjunction with data on OSHA command-and-control regulatory activity from 1972 to 1979, these data permitted an examination of the relationship between command-and-control regulatory activities and changes in industrial behavior that could be regarded as a form of self-regulation. This analysis showed that coercive regulation by OSHA in the 1970s was significantly related to industry self-regulation efforts, although the relationship varied by industrial facility employment size and type of regulatory coercion. These results indicate that coercive regulation should be retained as an industrial incentive in any self-regulation policy paradigm. The results also provide evidence that OSHA regulatory policy should be based on anticipated differences in industrial response to various coercive measures.

Magnetization mechanisms in ordered arrays of polycrystalline Fe{sub 100−x}Co{sub x} nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viqueira, M. S.; Bajales, N.; Urreta, S. E.

2015-05-28

Magnetization reversal processes and coercivity mechanisms in polycrystalline Fe{sub 100−x}Co{sub x} nanowire arrays, resulting from an AC electrodeposition process, are investigated. The array coercivity is described on the basis of polarization reversal mechanisms operating in individual wires, under the effect of inter-wire dipolar interactions described by a mean field approximation. For individual wires, a reversal mechanism involving the nucleation and further expansion of domain-wall like spin configuration is considered. The wires have a mean grain size larger than both the nanowire diameter and the exchange length, so localized and non-cooperative nucleation modes are considered. As the Co content increases, themore » alloy saturation polarization gradually decreases, but the coercive field and the relative remanence of the arrays increase, indicating that they are not controlled by the shape anisotropy in all the composition range. The coercive field dependence on the angle between the applied field and the wire long axis is not well described by reversal mechanisms involving nucleation and further displacement of neither vortex nor transverse ideal domain walls. On the contrary, the angular dependence of the coercive field observed at room temperature is well predicted by a model considering nucleation of inverse domains by localized curling, in regions smaller than the grain size, exhibiting quite small aspect ratios as compared to those of the entire nanowire. In arrays with higher Co contents, a transition from an initial (small angle) localized curling nucleation mechanism to another one, involving localized coherent rotation is observed at about π/4.« less

Effect of reductant and PVP on morphology and magnetic property of ultrafine Ni powders prepared via hydrothermal route

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jun, E-mail: j-zhang@126.com; Wang, Xiucai; Li, Lili

2013-10-15

Graphical abstract: The ultrafine Ni powders with the shapes including sphere, pearl-string, leaf, fish-bone, hexagonal sheet and silknet were prepared through one-step hydrothermal reduction using different reductants. Their saturation magnetization, remanent magnetization and coercivity sequentially increase, and the coercivity of hexagonal sheet-like Ni powders increases by 25% compared with the Ni bulk counterpart. - Highlights: • The ultrafine Ni powders with various shapes of sphere, fish-bone, hexagonal sheet, etc. • Facile and one-step hydrothermal reduction using three reductants and PVP additive was developed. • Magnetic properties of the ultrafine Ni powders with different shapes were measured. • Compared with bulkmore » Ni material, coercivity of hexagonal sheet Ni increases by 25%. • The formation mechanism of the shapes was suggested. - Abstract: The ultrafine nickel particles with different shapes including sphere, pearl-string, leaf, fish-bone, hexagonal sheet and silknet were prepared through one-step hydrothermal reduction using hydrazine hydrate, sodium hypophosphite and ethylene glycol as reductants, polyvinylpyrrolidone as structure-directing agent. It has been verified with the characterization of X-ray powder diffraction and transmission/scanning electronic microscopy that as-prepared products belong to face-centered cubic structure of nickel microcrystals with high purity and fine dispersity. The magnetic hysteresis loops measured at room temperature reveal that the values of saturation magnetization, remanent magnetization and coercivity rise sequentially from silknet, sphere to hexagonal sheet. In comparison with nickel bulk counterpart, the coercivity of the hexagonal sheet nickel powders increases by 25%.« less

A Reduced Basis Method with Exact-Solution Certificates for Symmetric Coercive Equations

DTIC Science & Technology

2013-11-06

the energy associated with the infinite - dimensional weak solution of parametrized symmetric coercive partial differential equations with piecewise...builds bounds with respect to the infinite - dimensional weak solution, aims to entirely remove the issue of the “truth” within the certified reduced basis...framework. We in particular introduce a reduced basis method that provides rigorous upper and lower bounds

Disciplinary Practices, Metaparenting, and the Quality of Parent--Child Relationships in African-American, Mexican-American, and European-American Mothers

ERIC Educational Resources Information Center

Holden, George W.; Hawk, Carol Kozak; Smith, Margaret M.; Singh, Jimmy P.; Ashraf, Rose

2017-01-01

Coercive responses to children's behavior are well recognized to be problematic for children's adjustment. Less well understood is how parental social cognition is linked to discipline. In this study we sought to link metaparenting--parents' thoughts about their parenting--to the use of coercive discipline. We predicted that mothers who engaged in…

High coercivity microcrystalline Nd-rich Nd-Fe-Co-Al-B bulk magnets prepared by direct copper mold casting

NASA Astrophysics Data System (ADS)

Zhao, L. Z.; Hong, Y.; Fang, X. G.; Qiu, Z. G.; Zhong, X. C.; Gao, X. S.; Liu, Z. W.

2016-06-01

High coercivity Nd25Fe40Co20Al15-xBx (x=7-15) hard magnets were prepared by a simple process of injection casting. Different from many previous investigations on nanocomposite compositions, the magnets in this work contain hard magnetic Nd2(FeCoAl)14B, Nd-rich, and Nd1+ε(FeCo)4B4 phases. The magnetic properties, phase evolution, and microstructure of the as-cast and annealed magnets were investigated. As the boron content increased from 7 to 11 at%, the intrinsic coercivity Hcj of the as-cast magnet increased from 816 to 1140 kA/m. The magnets annealed at 750 °C have shown more regular and smaller grains than the as-cast alloys, especially for the x=11 alloy. The high intrinsic coercivities for the annealed alloys with x=8~11 result from the presence of small-sized grains in the microstructure. The highest Hcj of 1427 kA/m was obtained for the heat treated alloy with x=10. This work provides an alternative approach for preparing fully dense Nd-rich bulk hard magnets with relatively good properties.

Effects of orientation on the time decay of magnetization for cobalt-alloy thin film media

NASA Astrophysics Data System (ADS)

Wang, J. P.; Alex, Michael; Tan, L. P.; Yan, M. L.

1999-04-01

The dependence of the time decay of magnetization on orientation ratio was investigated for longitudinal Co-alloy thin film media. The coercivity orientation ratio was controlled by the degree of mechanical texture. For oriented samples, it was found that the remanent magnetization along the circumferential direction decayed faster with time than that along the radial direction when the applied reverse magnetic field was near the remanent coercivity. However, the remanent magnetization along the circumferential direction decayed more slowly with time than that along the radial direction when the applied reverse magnetic field was less than roughly half the remanent coercivity. Anisotropic interactions and magnetic anisotropy distributions appear to be the cause for the different time decay of magnetization along the circumferential and radial directions for oriented media.

Magnetic properties of Ni nanoparticles dispersed in silica prepared by high-energy ball milling

NASA Astrophysics Data System (ADS)

González, E. M.; Montero, M. I.; Cebollada, F.; de Julián, C.; Vicent, J. L.; González, J. M.

1998-04-01

We analyze the magnetic properties of mechanically ground nanosized Ni particles dispersed in a SiO2 matrix. Our magnetic characterization of the as-milled samples show the occurrence of two blocking processes and that of non-monotonic milling time evolutions of the magnetic-order temperature, the high-field magnetization and the saturation coercivity. The measured coercivities exhibit giant values and a uniaxial-type temperature dependence. Thermal treatment carried out in the as-prepared samples result in a remarkable coercivity reduction and in an increase of the high-field magnetization. We conclude, on the basis of the consideration of a core (pure Ni) and shell (Ni-Si inhomogeneous alloy) particle structure, that the magnetoelastic anisotropy plays the dominant role in determining the magnetic properties of our particles.

Effect of low-melting point phases on the microstructure and properties of spark plasma sintered and hot deformed Nd-Fe-B alloys

NASA Astrophysics Data System (ADS)

Zhang, Li; Wang, Meiyu; Yan, Xueliang; Lin, Ye; Shield, Jeffrey

2018-04-01

The effect of adding a low melting point Pr-Cu-Al alloy during spark plasma sintering of melt-spun Nd-Fe-B ribbons is investigated. Regions of coarse grains were reduced and overall grain refinement was observed after the addition of Pr68Cu25Al7, leading to an enhancement of coercivity from 12.7 kOe to 20.4 kOe. Hot deformation of the samples in the spark plasma sintering system resulted in the formation of platelet-like grains, producing crystallographic alignment and magnetic anisotropy. The hot deformation process improved the remanence and energy product but reduced the coercivity. The decrease of coercivity resulted from grain growth and aggregation of Pr and Nd elements at triple-junction phases.

Magnetic and structural studies of trivalent Co-substituted Cd-Mn ferrites

NASA Astrophysics Data System (ADS)

Amer, M. A.; Meaz, T. M.; El-Kestawy, M.; Ghoneim, A. I.

2016-05-01

Series of polycrystalline Cd0.4Mn0.6CoxFe2-xO4 ferrites, 0≤x≤1, were prepared by solid state reaction method. The samples were characterized by inductive coupling plasma, X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectra and vibrating sample magnetometry. This study proved that all samples have single-phase cubic spinel structure. The true lattice constant, saturation magnetization, magnetic moment and trend of grain size and IR band νA showed decrease against x, whereas the trend of crystallite size, threshold frequency, Debye temperature, IR bands ν1 and ν2 and force constants F1 and F2, coercivity, anisotropy constant and residual magnetization showed increase. The IR analysis proved existence of Fe2+, Co2+, Fe4+, Co4+ and/or Mn4+ ions amongst the crystal sublattices. The characteristic bands ν1 and ν2 and force constants F1 and F2 showed decrease versus the tetrahedral- and octahedral-site bond length, respectively. The strain, specific surface area, refractive index, velocity, jump rate and remnant magnetization proved dependence on Co3+ ion content x.

Microstructure and properties of single crystal BaTiO3 thin films synthesized by ion implantation-induced layer transfer

NASA Astrophysics Data System (ADS)

Park, Young-Bae; Ruglovsky, Jennifer L.; Atwater, Harry A.

2004-07-01

Single crystal BaTiO3 thin films have been transferred onto Pt-coated and Si3N4-coated substrates by the ion implantation-induced layer transfer method using H + and He+ ion coimplantation and subsequent annealing. The transferred BaTiO3 films are single crystalline with root mean square roughness of 17nm. Polarized optical and piezoresponse force microscopy (PFM) indicate that the BaTiO3 film domain structure closely resembles that of bulk tetragonal BaTiO3 and atomic force microscopy shows a 90° a -c domain structure with a tetragonal angle of 0.5°-0.6°. Micro-Raman spectroscopy indicates that the local mode intensity is degraded in implanted BaTiO3 but recovers during anneals above the Curie temperature. The piezoelectric coefficient, d33, is estimated from PFM to be 80-100pm/V and the coercive electric field (Ec) is 12-20kV/cm, comparable to those in single crystal BaTiO3.

Magnetic and topographical modifications of amorphous Co-Fe thin films induced by high energy Ag7+ ion irradiation

NASA Astrophysics Data System (ADS)

Pookat, G.; Hysen, T.; Al-Harthi, S. H.; Al-Omari, I. A.; Lisha, R.; Avasthi, D. K.; Anantharaman, M. R.

2013-09-01

We have investigated the effects of swift heavy ion irradiation on thermally evaporated 44 nm thick, amorphous Co77Fe23 thin films on silicon substrates using 100 MeV Ag7+ ions fluences of 1 × 1011 ions/cm2, 1 × 1012 ions/cm2, 1 × 1013 ions/cm2, and 3 × 1013 ions/cm2. The structural modifications upon swift heavy irradiation were investigated using glancing angle X-ray diffraction. The surface morphological evolution of thin film with irradiation was studied using Atomic Force Microscopy. Power spectral density analysis was used to correlate the roughness variation with structural modifications investigated using X-ray diffraction. Magnetic measurements were carried out using vibrating sample magnetometry and the observed variation in coercivity of the irradiated films is explained on the basis of stress relaxation. Magnetic force microscopy images are subjected to analysis using the scanning probe image processor software. These results are in agreement with the results obtained using vibrating sample magnetometry. The magnetic and structural properties are correlated.

End-member modelling of isothermal remanent magnetization (IRM) acquisition curves: a novel approach to diagnose remagnetization

NASA Astrophysics Data System (ADS)

Gong, Z.; Dekkers, M. J.; Heslop, D.; Mullender, T. A. T.

2009-08-01

To identify remagnetization is essential for palaeomagnetic studies and their geodynamic implications. The traditional approach is often based on directional analysis of palaeomagnetic data and field tests, which may be inconclusive if the apparent polar wander path (APWP) is poorly constrained or if the remagnetization predates folding. In several cases, rock magnetic work, particularly, the measurement of hysteresis loops allows identification of the so-called `remagnetized' and `non-remagnetized' trends. However, for weakly magnetic samples, this approach can be equivocal. Here, to improve the diagnosis of remagnetization, we investigated 192 isothermal remanent magnetization (IRM) acquisition curves (up to 700 mT) of remagnetized and non-remagnetized limestones from the Organyà Basin, northern Spain. Also, 96 IRM acquisition curves from non-remagnetized marls were studied as a cross-check for the non-remagnetized limestones. A non-parametric end-member modelling approach is used to analyse the IRM acquisition curve data sets. First, remagnetized and non-remagnetized groups were treated separately. Two or three end-members were found to adequately describe the data variability: one end-member represents the high-coercivity contribution, whereas the low-coercivity part can be described by either one end-member or two reasonably similar end-members. In the remagnetized limestones, the low-coercivity end-members tend to saturate at higher field values than in the non-remagnetized limestones. When the entire data set was processed together, a three-end-member model was judged optimal. This model consists of a high-coercivity end-member, a low-coercivity end-member that saturates at ~300-400 mT and a low-coercivity end-member that approximately saturates at 700 mT. Higher contributions of the latter end-member appear to occur dominantly in the remagnetized limestones, whereas the reverse is true for the non-remagnetized limestones, so they plot in clearly distinguishable areas. Meanwhile, the IRM curves from non-remagnetized marls show a behaviour similar to that of the non-remagnetized end-member in the limestones. Therefore, this new approach can be a very useful tool to diagnose remagnetization in weakly magnetic limestones and marls. We recommend applying it to other areas of potentially remagnetized low-intensity sediments.

Effect of amino acid doping on the growth and ferroelectric properties of triglycine sulphate single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raghavan, C.M.; Sankar, R.; Mohan Kumar, R.

2008-02-05

Effect of amino acids (L-leucine and isoleucine) doping on the growth aspects and ferroelectric properties of triglycine sulphate crystals has been studied. Pure and doped crystals were grown from aqueous solution by low temperature solution growth technique. The cell parameter values were found to significantly vary for doped crystals. Fourier transform infrared analysis confirmed the presence of functional groups in the grown crystal. Morphology study reveals that amino acid doping induces faster growth rate along b-direction leading to a wide b-plane and hence suitable for pyroelectric detector applications. Ferroelectric domain structure has been studied by atomic force microscopy and hysteresismore » measurements reveal an increase of coercive field due to the formation of single domain pattern.« less

The state of science: violence and HIV infection in women.

PubMed

Manfrin-Ledet, Linda; Porche, Demetrius J

2003-01-01

Violence and human immunodeficiency virus (HIV) are two critical public health problems affecting the lives of millions of women today. The purpose of this article is to review the state of science that exists in linking the phenomena of violence and HIV infection in women. The history and scope of violence and HIV infection is presented. Theoretical models for the phenomena of violence and abuse against women and HIV risk behavior reduction are explored. The literature review consists of 44 research articles that examine risk factors for violence and HIV, violence associated with HIV/AIDS disclosure, history of violence and HIV/AIDS, forced or coercive sex and HIV/AIDS, and violence associated with HIV self-protection conduct. Implications for nursing practice and nursing research are presented.

Exchange-coupled hard magnetic Fe-Co/CoPt nanocomposite films fabricated by electro-infiltration

NASA Astrophysics Data System (ADS)

Wen, Xiao; Andrew, Jennifer S.; Arnold, David P.

2017-05-01

This paper introduces a potentially scalable electro-infiltration process to produce exchange-coupled hard magnetic nanocomposite thin films. Fe-Co/CoPt nanocomposite films are fabricated by deposition of CoFe2O4 nanoparticles onto Si substrate, followed by electroplating of CoPt. Samples are subsequently annealed under H2 to reduce the CoFe2O4 to magnetically soft Fe-Co and also induce L10 ordering in the CoPt. Resultant films exhibit 0.97 T saturation magnetization, 0.70 T remanent magnetization, 127 kA/m coercivity and 21.8 kJ/m3 maximum energy density. First order reversal curve (FORC) analysis and δM plot are used to prove the exchange coupling between soft and hard magnetic phases.

Magnetic characteristics of ultrafine Fe particles reduced from uniform iron oxide particles

NASA Astrophysics Data System (ADS)

Bridger, K.; Watts, J.; Tadros, M.; Xiao, Gang; Liou, S. H.; Chien, C. L.

1987-04-01

Uniform, cubic 0.05-μm iron oxide particles were formed by forced hydrolysis of ferric perchlorate. These particles were reduced to α-Fe by heating in hydrogen at temperatures between 300 and 500 °C. The effect of reduction temperature and various prereduction treatments on the microstructure of the iron particles will be discussed. Complete reduction to α-Fe was established by 57Fe Mössbauer spectroscopy and x-ray diffraction. Magnetic measurements on epoxy and polyurethane films containing these particles with various mass fractions gave coercivities as high as 1000 Oe. The relationship between the magnetic measurements and the microstructure will be discussed. Na2SiO3 is found to be the best coating material for the process of reducing iron oxide particles to iron.

Interlaboratory Comparison of Magnetic Thin Film Measurements.

PubMed

da Silva, F C S; Wang, C M; Pappas, D P

2003-01-01

A potential low magnetic moment standard reference material (SRM) was studied in an interlaboratory comparison. The mean and the standard deviation of the saturation moment m s, the remanent moment m r, and the intrinsic coercivity H c of nine samples were extracted from hysteresis-loop measurements. Samples were measured by thirteen laboratories using inductive-field loopers, vibrating-sample magnetometers, alternating-gradient force magnetometers, and superconducting quantum-interference-device magnetometers. NiFe films on Si substrates had saturation moment measurements reproduced within 5 % variation among the laboratories. The results show that a good candidate for an SRM must have a highly square hysteresis loop (m r/m s > 90 %), H c ≈ 400 A·m(-1) (5 Oe), and m s ≈ 2 × 10(-7) A·m(2) (2 × 10(-4) emu).

Microstructure evaluation for Dy-free Nd-Fe-B sintered magnets with high coercivity

NASA Astrophysics Data System (ADS)

Goto, R.; Matsuura, M.; Sugimoto, S.; Tezuka, N.; Une, Y.; Sagawa, M.

2012-04-01

Nd-Fe-B sintered magnets are used for motors of hybrid or electric vehicles due to their high energy products. Dy is added to Nd-Fe-B sintered magnets to work in a high temperature environment. Although the addition of Dy decreases the magnetization of Nd-Fe-B magnets, it increases coercivity; a decrease in the amount of Dy is strongly required. Recently, Nd-Fe-B sintered magnets with a grain size of 1 μm achieved high coercivity of ˜20 kOe without the addition of Dy or other heavy rare earth elements. In this paper, the microstructure of their magnets was observed and compared to magnets with a grain size of ˜3 μm. The coercivity of magnets consisting of larger particles was 17 kOe. Microstructures were observed by the scanning electron microscope and the shapes of grains and the distribution of the Nd-rich phase were evaluated. The observation was promoted in two directions. One direction is the plane perpendicular to the magnetically aligned direction (c plane side) and the other is the side parallel to the magnetically aligned direction (c axis side). For magnets consisting of smaller particles, the shapes of grains are isotropic for the c plane side and elongated for the c axis side. The angle of minor axis prefers to be parallel to magnetically aligned direction. The distribution of the Nd-rich phase for magnets was also evaluated for both magnets. The distribution of the Nd-rich phase at triple junctions for the magnets with smaller particles becomes homogeneous compared to that for magnets with larger particles. It is considered that Dy-free magnets with high coercivity were realized by the achievement of homogeneous distribution of Nd-rich phase besides decreasing grain size.

Magnetic performance change of multi-main-phase Nd-Ce-Fe-B magnets by diffusing (Nd, Pr)H x

NASA Astrophysics Data System (ADS)

Ma, Tianyu; Zhang, Wenying; Peng, Baixing; Liu, Yongsheng; Chen, Yongjie; Wang, Xinhua; Yan, Mi

2018-02-01

The grain boundary diffusion process (GBDP) is effective to enhance coercivity of the single-main-phase (SMP) RE2Fe14B (rare earth (RE)) magnets through forming magnetic hardening shells surrounding the hard grain cores. Here, the GBDP was applied to the multi-main-phase (MMP) (Nd, Pr)22.3Ce8.24FebalM1.0B1.0 (wt.%) magnets prepared by sintering the mixture of Ce-free and Ce-containing 2:14:1 powders, which have shown superior magnetic properties, especially coercivity, to the SMP ones at the same average composition. The remanence of the (Nd, Pr)H x diffused magnets increases gradually with the increase of diffusion temperature from 480 to 880 °C, the coercivity, however, slightly decreases. The highest (BH)max of 350.1 kJ m-3 is achieved when diffusing at 680 °C, which is 9.2% higher than 320.7 kJ m-3 for the as-prepared magnet. The remanence increment is due to the diffusion of Nd/Pr into the 2:14:1 phase grains, enlarging the intrinsic saturation magnetic polarization. The slight coercivity reduction is due to the gradual homogenization of RE distribution within the 2:14:1 grains of the undiffused parts, i.e. approaching the ‘close to equilibrium (or SMP)’ state, which offsets the positive contributions from the enrichment of Nd/Pr in the Ce-rich 2:14:1 phase and the formation of continuous RE-rich intergranular phase. These findings suggest that the GBDP effect on coercivity of the MMP Nd-Ce-Fe-B magnets is distinctly different from the SMP ones, and that the chemical heterogeneity should be carefully controlled to improve the magnetic properties of such high cost-performance permanent magnets.

Crossing the Threshold From Porn Use to Porn Problem: Frequency and Modality of Porn Use as Predictors of Sexually Coercive Behaviors.

PubMed

Marshall, Ethan A; Miller, Holly A; Bouffard, Jeff A

2017-11-01

According to recent statistics, as many as one in five female college students are victims of sexual assault during their college career. To combat what has been called the "Campus Rape Crisis," researchers have attempted to understand what variables are associated with sexually coercive behaviors in college males. Although investigators have found support for the relationship between pornography consumption and sexually coercive behavior, researchers typically operationalize pornography use in terms of frequency of use. Furthermore, frequency of use has been assessed vaguely and inconsistently. The current study offered a more concrete assessment of frequency of use and an additional variable not yet included for pornography use: number of modalities. Beyond examining the relationship between pornography use and sexual coercion likelihood, the current study was the first to use pornography variables in a threshold analysis to test whether there is a cut point that is predictive of sexual coercion likelihood. Analyses were conducted with a sample of 463 college males. Results indicated that both pornography use variables were significantly related to a higher likelihood of sexually coercive behaviors. When both frequency of use and number of modalities were included in the model, modalities were significant and frequency was not. In addition, significant thresholds for both pornography variables that predicted sexual coercion likelihood were identified. These results imply that factors other than frequency of use, such as number of modalities, may be more important for the prediction of sexual coercive behaviors. Furthermore, threshold analyses revealed the most significant increase in risk occurred between one modality and two, indicating that it is not pornography use in general that is related to sexual coercion likelihood, but rather, specific aspects of pornography use.

Out-of-plane coercive field of Ni 80Fe 20 antidot arrays

NASA Astrophysics Data System (ADS)

Gao, Chunhong; Chen, Ke; Lü, Ling; Zhao, Jianwei; Chen, Peng

2010-11-01

The out-of-plane magnetic anisotropy and out-of-plane magnetization reversal process of nanoscale Ni 80Fe 20 antidot arrays deposited by magnetron sputtering technique on an anodic aluminum oxide (AAO) membrane are investigated. The angular dependence of out-of-plane remanent magnetization of Ni 80Fe 20 antidot arrays shows that the maximum remanence is in-plane and the squareness of the out-of-plane hysteresis loop follow a |cos θ| dependence. The angular dependence of out-of-plane coercivity of Ni 80Fe 20 antidot arrays shows that the maximum coercivity lies on the surface of a cone with its symmetric axis normal to the sample plane, which indicates a transition of magnetic reversal from curling to coherent rotation when changing the angle between the applied magnetic field and the sample plane.

Low temperature diffusion process using rare earth-Cu eutectic alloys for hot-deformed Nd-Fe-B bulk magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akiya, T., E-mail: akiya.takahiro@nims.go.jp; Sepehri-Amin, H.; Ohkubo, T.

2014-05-07

The low temperature grain boundary diffusion process using RE{sub 70}Cu{sub 30} (RE = Pr, Nd) eutectic alloy powders was applied to sintered and hot-deformed Nd-Fe-B bulk magnets. Although only marginal coercivity increase was observed in sintered magnets, a substantial enhancement in coercivity was observed when the process was applied to hot-deformed anisotropic bulk magnets. Using Pr{sub 70}Cu{sub 30} eutectic alloy as a diffusion source, the coercivity was enhanced from 1.65 T to 2.56 T. The hot-deformed sample expanded along c-axis direction only after the diffusion process as RE rich intergranular layers parallel to the broad surface of the Nd{sub 2}Fe{sub 14}B are thickened inmore » the c-axis direction.« less

The Role of Control in Intimate Partner Violence: A Study in Dutch Forensic Outpatients.

PubMed

Verschuere, Bruno; van Horn, Joan; Buitelaar, Nannet

2018-05-01

Johnson argued that coercive control is crucial in explaining heterogeneity in intimate partner violence, with such violence being more frequent, less reciprocal, and more often male-to-female aggression when it serves to exercise control over the partner. We assessed 280 Dutch forensic outpatients who had recently engaged in intimate partner violence on nonaggressive coercive control. Control showed significant, small to moderate, associations with more frequent past year acts of psychological aggression, physical assault, and sexual coercion and more frequently resulted in partner injury. Control was unrelated to reciprocity of partner violence. High controlling violence was enacted mostly, but not exclusively by men. Overall, while perhaps not having a uniquely strong association, our findings provide partial support for the role of coercive control in intimate partner violence and suggest it may benefit intimate partner violence risk assessment.

Effective reduction of the coercivity for Co72Pt28 thin film by exchange coupled Co81Ir19 soft layer with negative magnetocrystalline anisotropy

NASA Astrophysics Data System (ADS)

Jiao, J. Y.; Ma, T. Y.; Li, Z. W.; Qiao, L.; Wang, Y.; Wang, T.; Li, F. S.

2018-02-01

We report on the investigation of coercivity changes of the Co72Pt28/Co81Ir19 exchange-coupled composite (ECC) media with negative soft-layer (SL) magnetocrystalline anisotropy (MA). Our results show that the hard-layer (HL) of our sample exhibits a columnar type microstructure with well isolated grains and the SL with hcp-structure grows on top of the HL with the same texture. Therefore, strong coupling of the two layers have been realized as evidenced by the magnetic characterization. Importantly, we observe a more effective reduction of the coercivity of the ECC media by using SLs with negative MA when compared to the use of SLs with positive or negligible MA. The experimental results are corroborated by theoretical calculations.

Sex Differences in Intimate Partner Violence and the Use of Coercive Control as a Motivational Factor for Intimate Partner Violence

ERIC Educational Resources Information Center

Tanha, Marieh; Beck, Connie J. A.; Figueredo, Aurelio Jose; Raghavan, Chitra

2010-01-01

Research argues that coercive control (CC) is a special case of intimate partner violence (IPV). The present study hypothesized that instead CC is the "motivator" for other types of IPV, with control of the victim as the goal. When CC fails, physical types of IPV are used. This hypothesized relationship was tested using a large matched sample of…

Independent Contributions of Early Positive Parenting and Mother-Son Coercion on Emerging Social Development.

PubMed

Akcinar, Berna; Shaw, Daniel S

2018-06-01

In the current study, we explored associations between parent-child coercion and positive parenting in the toddler period in relation to children's social-behavioral development during the school-age period. The data were drawn from the Pitt Mother & Child Project, a sample of 310 low-income, ethnically diverse boys. Drawing on tenets of both attachment and social learning theory, it was hypothesized that coercive mother-son interaction would lead to reductions in positive maternal parenting in the toddler period, and that both positive parenting and mother-son coercion in the toddler period would contribute to children's conduct problems at school entry and lower social skills and peer rejection in middle childhood. The results were largely confirmed, such that mother-son coercive interaction at 18 months was related to decreases in positive parenting at 24 months. Additionally, mother-son coercive interaction and positive parenting at 24 months were linked to child conduct problems at age 5, which in turn predicted child social skills and peer rejection during middle childhood. In addition to indirect effects through child conduct problems, mother-son coercion continued to be independently related to school-age peer rejection. The findings are discussed with respect to the importance of early coercive interactions in the growth of child social-behavioral development from early to middle childhood.

Perspectives for high-performance permanent magnets: applications, coercivity, and new materials

NASA Astrophysics Data System (ADS)

Hirosawa, Satoshi; Nishino, Masamichi; Miyashita, Seiji

2017-03-01

High-performance permanent magnets are indispensable in the production of high-efficiency motors and generators and ultimately for sustaining the green earth. The central issue of modern permanent magnetism is to realize high coercivity near and above room temperature on marginally hard magnetic materials without relying upon the critical elements such as heavy rare earths by means of nanostructure engineering. Recent investigations based on advanced nanostructure analysis and large-scale first principles calculations have led to significant paradigm shifts in the understandings of coercivity mechanism in Nd-Fe-B permanent magnets, which includes the discovery of the ferromagnetism of the thin (2 nm) intergranular phase surrounding the Nd2Fe14B grains, the occurrence of negative (in-plane) magnetocrystalline anisotropy of Nd ions and some Fe atoms at the interface which degrades coercivity, and visualization of the stochastic behaviors of magnetization in the magnetization reversal process at high temperatures. A major change may occur also in the motor topologies, which is currently overwhelmed by the magnetic flux weakening interior permanent magnet motor type, to other types with variable flux permanent magnet type in some applications to open up a niche for new permanent magnet materials. Keynote talk at 8th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN2016), 8-12 November 2016, Ha Long City, Vietnam.

Observational study of aggressive behaviour and coercion on an Indian acute ward.

PubMed

Danivas, Vijay; Lepping, Peter; Punitharani, Shivanna; Gowrishree, Handithavalli; Ashwini, Kundapur; Raveesh, Bevinahalli Nanjegowda; Palmstierna, Tom

2016-08-01

We evaluated prevalence of aggressive behaviour and coercive measures on an acute Indian psychiatric ward where relatives are always present at the ward. Non-interacting, independent observers (specifically trained mental health clinicians) on an Indian acute, 20-bedded psychiatric ward gave structured reports on all violent episodes and coercive measures during a 30-day period. They used the Staff Observation Aggression Scale -Revised, Indian (SOAS-RI). The severity of the SOAS-RI reports were independently analysed by one of the authors. 229 violent incidents were recorded, involving 63% of admitted patients. 27% of all admitted patients were subjected to intravenous injections. Relatives provoked 35% of the incidents and were the target in 56% of the incidents. Patientś own relatives were involved in managing the aggression in 35% of the incidents. Relatives of other patients were involved in 14% of the incidents. The likelihood of a patient to be physically restrained and that a relative would be participating in the coercive measures was increased when medical staff was targeted. Relatives are commonly triggers and victims of aggressions on the inverstigated acute Indian psychiatric wards. Doctors and nurses are less likely to be victims but aggression towards them leads more commonly to coercive measures. Copyright © 2016 Elsevier B.V. All rights reserved.

Growth and giant coercive field of spinel-structured Co3- x Mn x O4 thin films

NASA Astrophysics Data System (ADS)

Kwak, Yongsu; Song, Jonghyun; Koo, Taeyeong

2016-08-01

We grew epitaxial thin films of CoMn2O4 and Co2MnO4 on Nb-doped SrTiO3(011) and SrTiO3(001) single crystal substrates using pulsed laser deposition. The magnetic Curie temperature ( T c ) of the Co2MnO4 thin films was ~176 K, which is higher than that of the bulk whereas CoMn2O4 thin films exhibited a value of T c (~151 K) lower than that of the bulk. For the Co2MnO4 thin films, the M - H loop showed a coercive field of ~0.7 T at 10 K, similar to the value for the bulk. However, the M -H loop of the CoMn2O4(0 ll) thin film grown on a Nb-doped SrTiO3(011) substrate exhibited a coercive field of ~4.5 T at 30 K, which is significantly higher than those of the Co2MnO4 thin film and bulk. This giant coercive field, only observed for the CoMn2O4(0 ll) thin film, can be attributed to the shape anisotropy and strong spin-orbit coupling.

Structure and magnetic properties of L10-MnGa nanoparticles prepared using direct reactions between Mn nanoparticles and Ga

NASA Astrophysics Data System (ADS)

Si, P. Z.; Qian, H. D.; Park, J.; Ge, H. L.; Shinde, K. P.; Chung, K. C.; Choi, C. J.

2018-05-01

The tetragonal L10-Mn1+xGa (x<0.8) nanoparticles and bcc-Mn23Ga77 nanoparticles with large coercivity were prepared using direct reactions between Mn nanoparticles and Ga at elevated temperatures. The Mn23Ga77 phase was formed at ˜573 K while the L10-structured Mn1+xGa was formed at ˜850 K. After ball-milling, the L10-Mn1+xGa nanoparticles transformed into nano-flakes with enhanced coercivity. The size of the as-prepared Mn23Ga77 nanoparticles is comparable to that of the precursor Mn nanoparticles. An aggregation of the nanoparticles and thus a larger particle size were observed in the L10-Mn1+xGa nanoparticles obtained at 850 K. The size of the L10-Mn1+xGa nano-flakes is reduced to about 200-400 nm with a thickness of ˜20 nm. The coercivity of the Mn23Ga77 nanoparticles and the L10-Mn1+xGa nanoparticles at 300 K reached up to 0.2 T and 0.43 T, respectively. The coercivity of L10-Mn1+xGa ball-milled nano-flakes is 0.59 T at 300 K.

Microstructures, magnetic properties and coercivity mechanisms of Nd-Ce-Fe-B based alloys by Zr substitution

NASA Astrophysics Data System (ADS)

Wang, Lei; Quan, Qichen; Zhang, Lili; Hu, Xianjun; Ur Rehman, Sajjad; Jiang, Qingzheng; Du, Junfeng; Zhong, Zhenchen

2018-03-01

In this paper, the effects of Zr addition on microstructures, magnetic properties, exchange coupling, and coercivity mechanisms of Nd-Ce-Fe-B alloys fabricated by melt-spinning technique are investigated. It is found that the coercivity Hcj is enhanced significantly by Zr substitution in the (Nd0.8Ce0.2)13Fe82-xZrxB5 alloys, while the remanence Jr is reduced slightly. The Hcj increases from 12.2 to 13.7 kOe by adding Zr up to 1.5 at. %, whereas Hcj is decreased with a further increase in Zr content. The larger lattice constants and unit cell volumes of the matrix phase indicate that Zr atoms enter into the hard magnetic phase by substituting Fe sites. The reduction of Tc implies the attenuation of the exchange interaction in the 2:14:1 phase with Zr occupying the Fe sites. The weakened intergranular exchange coupling of the Zr added alloy may be attributed to the formation of a non-magnetic intergranular phase. It is worth noting that the coercivity is dominated by the pinning of domain walls at defect positions even though the nucleation of reversal domains still exists. The synergistic function between the pinning effect and the exchange coupling leads to improved magnetic properties.

Quantitative study of FORC diagrams in thermally corrected Stoner- Wohlfarth nanoparticles systems

NASA Astrophysics Data System (ADS)

De Biasi, E.; Curiale, J.; Zysler, R. D.

2016-12-01

The use of FORC diagrams is becoming increasingly popular among researchers devoted to magnetism and magnetic materials. However, a thorough interpretation of this kind of diagrams, in order to achieve quantitative information, requires an appropriate model of the studied system. For that reason most of the FORC studies are used for a qualitative analysis. In magnetic systems thermal fluctuations "blur" the signatures of the anisotropy, volume and particle interactions distributions, therefore thermal effects in nanoparticles systems conspire against a proper interpretation and analysis of these diagrams. Motivated by this fact, we have quantitatively studied the degree of accuracy of the information extracted from FORC diagrams for the special case of single-domain thermal corrected Stoner- Wohlfarth (easy axes along the external field orientation) nanoparticles systems. In this work, the starting point is an analytical model that describes the behavior of a magnetic nanoparticles system as a function of field, anisotropy, temperature and measurement time. In order to study the quantitative degree of accuracy of our model, we built FORC diagrams for different archetypical cases of magnetic nanoparticles. Our results show that from the quantitative information obtained from the diagrams, under the hypotheses of the proposed model, is possible to recover the features of the original system with accuracy above 95%. This accuracy is improved at low temperatures and also it is possible to access to the anisotropy distribution directly from the FORC coercive field profile. Indeed, our simulations predict that the volume distribution plays a secondary role being the mean value and its deviation the only important parameters. Therefore it is possible to obtain an accurate result for the inversion and interaction fields despite the features of the volume distribution.

Iron in the Fire: Searching for Fire's Magnetic Fingerprint using Controlled Heating Experiments, High-Resolution FORCs, IRM Coercivity Spectra, and Low-Temperature Remanence Experiments

NASA Astrophysics Data System (ADS)

Lippert, P. C.; Reiners, P. W.

2014-12-01

Evidence for recent climate-wildfire linkages underscores the need for better understanding of relationships between wildfire and major climate shifts in Earth history, which in turn offers the potential for prognoses for wildfire and human adaptations to it. In particular, what are the links between seasonality and wildfire frequency and severity, and what are the feedbacks between wildfire, landscape evolution, and biogeochemical cycles, particularly the carbon and iron cycles? A key first step in addressing these questions is recovering well-described wildfire records from a variety of paleolandscapes and paleoclimate regimes. Although charcoal and organic biomarkers are commonly used indicators of fire, taphonomic processes and time-consuming analytical preparations often preclude their routine use in some environments and in high-stratigraphic resolution paleowildfire surveying. The phenomenological relationship between fire and magnetic susceptibility can make it a useful surveying tool, but increased magnetic susceptibility in sediments is not unique to fire, and thus limits its diagnostic power. Here we utilize component-specific rock magnetic methods and analytical techniques to identify the rock magnetic fingerprint of wildfire. We use a custom-designed air furnace, a series of iron-free laboratory soils, natural saprolites and soils, and fuels from Arizona Ponderosa pine forests and grasslands to simulate wildfire in a controlled and monitored environment. Soil-ash residues and soil and fuel controls were then characterized using First Order Reversal Curve (FORC) patterns, DC backfield IRM coercivity spectra, low-temperature SIRM demagnetization behavior, and low-temperature cycling of room-temperature SIRM behavior. We will complement these magnetic analyses with high-resolution TEM of magnetic extracts. Here we summarize the systematic changes to sediment magnetism as pyrolitized organic matter is incorporated into artificial and natural soils. These observations help us elucidate the processes and sources responsible for increases in magnetic susceptibility observed in natural burned soils, as well as identify a unique rock magnetic fingerprint for natural wildfire that has the potential to be preserved in sedimentary sequences in the geological record.

Temperature dependence of ferromagnet-antiferromagnet spin alignment and coercivity in epitaxial micromagnet bilayers

DOE PAGES

Lee, Michael S.; Wynn, Thomas A.; Folven, Erik; ...

2017-06-26

In this paper, soft x-ray photoemission electron microscopy with an in situ magnetic field has been used to study the relationship between ferromagnetic and antiferromagnetic spin alignment and the switching/reversal field of epitaxial micromagnetic structures. We investigated a model system consisting of a bilayer of ferromagnetic La 0.7Sr 0.3MnO 3 and antiferromagnetic LaFeO 3 where the spin axes in each layer can be driven from mutually perpendicular (spin-flop) to parallel alignment by varying the temperature between 30 and 300 K. Results show that not only does this spin alignment noticeably influence the bilayer micromagnet coercivity compared to La 0.7Sr 0.3MnOmore » 3 single-layer micromagnets, but the coercivity within this materials system can be tuned over a wide range by careful balance of material properties.« less

Structural and magnetic properties of new uniaxial nanocrystalline Pr5Co19 compound

NASA Astrophysics Data System (ADS)

Bouzidi, W.; Mliki, N.; Bessais, L.

2017-11-01

Highly-coercive nanocrystalline Pr5Co19 powders have been synthesized by mechanical milling for the first time. The structural properties are studied by X-ray diffraction and refined with Rietveld method. This analysis revealed that whatever annealing temperature, samples crystallize in the rhombohedral (3R) of Ce5Co19-type structure (space group R 3 bar m). The magnetization curve as a function of temperature shows a magnetic transition state at the Curie temperature TC = 690 K. The optimum hard magnetic properties have been obtained for Pr5Co19 milled for 5 h and annealed at 1048 K for 30 min. These alloys exhibit a coercivity of 15 kOe at room temperature. This high coercivity is attributed to the high uniaxial magnetocrystalline anisotropy, nanoscale grain size, and to the homogeneous nanostructure developed by mechanical milling process and subsequent annealing.

Public attitudes toward legally coerced biological treatments of criminals

PubMed Central

Berryessa, Colleen M.; Chandler, Jennifer A.; Reiner, Peter

2016-01-01

Abstract How does the public view the offer of a biological treatment in lieu of prison for criminal offenders? Using the contrastive vignette technique, we explored this issue, using mixed-methods analysis to measure concerns regarding changing the criminal's personality, the coercive nature of the offer, and the safety of the proposed treatment. Overall, we found that of the three variables, the safety of the pill had the strongest effect on public acceptance of a biological intervention. Indeed, it was notable that the public was relatively sanguine about coercive offers of biological agents, as well as changing the personality of criminals. While respondents did not fully endorse such coercive offers, neither were they outraged by the use of biological treatments of criminals in lieu of incarceration. These results are discussed in the context of the retributive and rehabilitative sentiments of the public, and legal jurisprudence in the arena of human rights law. PMID:28852535

Public attitudes toward legally coerced biological treatments of criminals.

PubMed

Berryessa, Colleen M; Chandler, Jennifer A; Reiner, Peter

2016-12-01

How does the public view the offer of a biological treatment in lieu of prison for criminal offenders? Using the contrastive vignette technique, we explored this issue, using mixed-methods analysis to measure concerns regarding changing the criminal's personality, the coercive nature of the offer, and the safety of the proposed treatment. Overall, we found that of the three variables, the safety of the pill had the strongest effect on public acceptance of a biological intervention. Indeed, it was notable that the public was relatively sanguine about coercive offers of biological agents, as well as changing the personality of criminals. While respondents did not fully endorse such coercive offers, neither were they outraged by the use of biological treatments of criminals in lieu of incarceration. These results are discussed in the context of the retributive and rehabilitative sentiments of the public, and legal jurisprudence in the arena of human rights law.

Magnetic properties of (misch metal, Nd)-Fe-B melt-spun magnets

NASA Astrophysics Data System (ADS)

Li, R.; Shang, R. X.; Xiong, J. F.; Liu, D.; Kuang, H.; Zuo, W. L.; Zhao, T. Y.; Sun, J. R.; Shen, B. G.

2017-05-01

The effect of replacing Nd with misch metal (MM) on magnetic properties and thermal stability has been investigated on melt-spun (Nd1-xMMx)13.5Fe79.5B7 ribbons by varying x from 0 to 1. All of the alloys studied crystallize in the tetragonal 2:14:1 structure with single hard magnetic phase. Curie temperature (Tc), coercivity (Hcj), remanence magnetization (Br) and maximum energy product ((BH)max) all decrease with MM content. The melt-spun MM13.5Fe79.5B ribbons with high ratio of La and Ce exhibit high magnetic properties of Hcj = 8.2 kOe and (BH)max= 10.3 MGOe at room temperature. MM substitution also significantly strengthens the temperature stability of coercivity. The coercivities of the samples with x = 0.2 and even 0.4 exhibit large values close to that of Nd13.5Fe79.5B7 ribbons above 400 K.

Scientific and conceptual flaws of coercive treatment models in addiction.

PubMed

Uusitalo, Susanne; van der Eijk, Yvette

2016-01-01

In conceptual debates on addiction, neurobiological research has been used to support the idea that addicted drug users lack control over their addiction-related actions. In some interpretations, this has led to coercive treatment models, in which, the purpose is to 'restore' control. However, neurobiological studies that go beyond what is typically presented in conceptual debates paint a different story. In particular, they indicate that though addiction has neurobiological manifestations that make the addictive behaviour difficult to control, it is possible for individuals to reverse these manifestations through their own efforts. Thus, addicted individuals should not be considered incapable of making choices voluntarily, simply on the basis that addiction has neurobiological manifestations, and coercive treatment models of addiction should be reconsidered in this respect. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Substantial enhancement in intrinsic coercivity on M-type strontium hexaferrite through the increase in magneto-crystalline anisotropy by co-doping of group-V and alkali elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Kyunghan, E-mail: kyunghan.ahn@samsung.com; Ryu, Byungki; Korolev, Dmitry

2013-12-09

The effect of d{sup 1} impurity doping in Sr-hexaferrite (SrM) on the magnetic anisotropy is investigated. First-principles calculations revealed that group-V elements (V, Nb) are stabilized with co-doping of alkali elements. Na{sup 1+}/K{sup 1+} doping at Sr{sup 2+}-site is found to be critical to form the d{sup 1} impurities at Fe-site. Experimentally, Na–V doped SrM shows the intrinsic coercivity of ∼5.4 kOe, which is ∼300% enhancement compared to undoped SrM and comparable value to La–Co co-doped SrM. Finally, the spin-orbit coupling from non-vanishing angular momentum of d{sup 1} impurity in SrM should be a main factor for such a substantialmore » improvement of intrinsic coercivity.« less

Plasma-assisted synthesis and study of structural and magnetic properties of Fe/C core shell

NASA Astrophysics Data System (ADS)

Shinde, K. P.; Ranot, M.; Choi, C. J.; Kim, H. S.; Chung, K. C.

2017-07-01

Pure and carbon-encapsulated iron nanoparticles with an average diameter of 25 nm were synthesized by using the DC plasma arc discharge method. Fe core nanoparticles were encapsulated with carbon layer, which is acting as protection layer against both oxidation and chemical reaction. The morphology and the Fe/C core/shell structure of the nanoparticles were studied by using field emission scanning electron microscopy and transmission electron microscopy. The x-ray diffraction study showed that the α-Fe phase exists with γ-Fe as an impurity. The studied samples have been interrelated with the variation of saturation magnetization, remanent magnetization and coercive field with the amount of carbon coating. The pure α-Fe sample shows saturation magnetization = 172 emu/g, and coercive field = 150 Oe, on the other hand few layer carbon coated α-Fe sample shows saturation magnetization =169 emu/g with higher coercive field 398 Oe.

Coercivity mechanisms and thermal stability of thin film magnetic recording media

NASA Astrophysics Data System (ADS)

Yang, Cheng

1999-09-01

Coercivity mechanisms and thermal stability of magnetic recording media were studied. It was found that magnetization reversal mainly occurs by nucleation mechanism. The correlation was established between the c/ a ratio of Co HCP structure and other process parameters that are thought to be the dominant factors in determining the anisotropy and therefore the coercivity of Co based thin film magnetic recording media. Time decay and switching of the magnetization in thin film magnetic recording media depend on the grain size distribution and easy-axis orientation distribution according to the proposed two- energy-level model. Relaxation time is the most fundamental parameter that determines the time decay performance of the magnetic recording media. An algorithm was proposed to calculate its distribution directly from the experimental data without any presumption. It was found for the first time that the distribution of relaxation time takes the form of Weibull distribution.

Temperature dependence of ferromagnet-antiferromagnet spin alignment and coercivity in epitaxial micromagnet bilayers

NASA Astrophysics Data System (ADS)

Lee, Michael S.; Wynn, Thomas A.; Folven, Erik; Chopdekar, Rajesh V.; Scholl, Andreas; Retterer, Scott T.; Grepstad, Jostein K.; Takamura, Yayoi

2017-06-01

Soft x-ray photoemission electron microscopy with an in situ magnetic field has been used to study the relationship between ferromagnetic and antiferromagnetic spin alignment and the switching/reversal field of epitaxial micromagnetic structures. We investigated a model system consisting of a bilayer of ferromagnetic L a0.7S r0.3Mn O3 and antiferromagnetic LaFe O3 where the spin axes in each layer can be driven from mutually perpendicular (spin-flop) to parallel alignment by varying the temperature between 30 and 300 K. Results show that not only does this spin alignment noticeably influence the bilayer micromagnet coercivity compared to L a0.7S r0.3Mn O3 single-layer micromagnets, but the coercivity within this materials system can be tuned over a wide range by careful balance of material properties.

Magnetic properties of Sr 3 NiIrO 6 and Sr 3 CoIrO 6 : Magnetic hysteresis with coercive fields of up to 55 T

DOE PAGES

Singleton, John; Kim, Jae Wook; Topping, Craig V.; ...

2016-12-08

Here, we report extraordinarily large magnetic hysteresis loops in the iridates Sr 3NiIrO 5 and Sr 3CoIrO 6. We find coercive magnetic fields of up to 55 T with switched magnetic moments ≈1μ B per formula unit in Sr 3NiIrO 6 and coercive fields of up to 52 T with switched moments ≈3μ B per formula unit in Sr 3CoIrO 6. We propose that the magnetic hysteresis involves the field-induced evolution of quasi-one-dimensional chains in a frustrated triangular configuration. In conclusion, the striking magnetic behavior is likely to be linked to the unusual spin-orbit-entangled local state of the Ir 4+more » ion and its potential for anisotropic exchange interactions.« less

Feasibility study of electrophoresis deposition of DyF3 on Nd-Fe-B particles for coercivity enhancement

NASA Astrophysics Data System (ADS)

Kim, K. M.; Kang, M. S.; Kwon, H. W.; Lee, J. G.; Yu, J. H.

2018-05-01

Feasibility of the electrophoresis deposition (EPD) technique for homogeneous and adhesive deposition of DyF3 particles on the Nd-Fe-B-type particles was studied, and coercivity enhancement in the diffusion-treated Nd-Fe-B-type particles deposited with DyF3 by EPD was investigated. HDDR-treated Nd12.5Fe80.6B6.4Ga0.3Nb0.2 particles were deposited with DyF3 particles by EPD. More homogeneous and adhesive deposition of DyF3 particles on the surface of Nd-Fe-B particles was made by the EPD with respect to conventional dip-coating, and this led to more active and homogeneous diffusion of Dy. More profound coercivity enhancement was achieved in the diffusion-treated Nd-Fe-B-type particles deposited with DyF3 by EPD compared to dip-coated particles.

Public Law No. 101-167 of 21 November 1989, Foreign Operations, Export Financing, and Related Programs Appropriations Act, 1990.

PubMed

1989-01-01

Among other things, this US Act makes appropriations for foreign operations, export financing, and related programs. With respect to these appropriations, it does the following: 1) prohibits funding for coercive abortion or forced sterilization as part of bilateral development and population planning assistance; 2) prohibits the use of funds appropriated under the Act to lobby for abortion; and 3) prohibits the use of development assistance funds to pay for abortions or involuntary sterilizations as a method of family planning or to motivate or coerce any persons to practice abortions or undergo sterilization, or any biomedical research concerning abortions or involuntary sterilization as a method of family planning. The Act also reaffirms the congressional commitment to population planning, development assistance, and the need for informed voluntary family planning.

Studies of isolated and interacting ferromagnetic gapped nanorings

NASA Astrophysics Data System (ADS)

Li, Jie; Zhang, Sheng; Bartell, Jason; Grigas, Chris; Nisoli, Cristiano; Lammert, Paul; Crespi, Vincent; Schiffer, Peter

2011-03-01

We have used micromagnetic simulation and magnetic force microscopy (MFM) to study isolated and interacting permalloy nanorings that are lithographically fabricated with gaps that prevent a rotationally symmetric magnetic state. The gapped nanorings have inner and outer radii of 200 and 300 nm respectively, and the gap has a subtended width of ~ 20 degrees. The nanorings generate a strong magnetic field only in the gap, and thus the magnetization states of gapped nanorings are much more accessible to MFM imaging than complete rings. We have investigated the properties of these gapped nanorings, including the anisotropy in their coercive field and the relative alignment of the magnetic polarization in coupled pairs. We acknowledge the financial support from DOE and Army Research Office.We are grateful to Professor Chris Leighton and Mike Erickson for assistance with sample preparation.

Low frequency creep in CoNiFe films

NASA Technical Reports Server (NTRS)

Bartran, D. S.; Bourne, H. C., Jr.; Chow, L. G.

1972-01-01

The results of an investigation of domain wall motion excited by slow rise-time, bipolar, hard-axis pulses in vacuum deposited CoNiFe films 1500A to 2000A thick are presented. The results are consistent with those of comparable NiFe films in spite of large differences in film properties. The present low frequency creep data together with previously published results in this and other laboratories can be accounted for by a model which requires that the wall structure change usually associated with low frequency creep be predominately a gyromagnetic process. The correctness of this model is reinforced by the observation that the wall coercive force, the planar wall mobility, and the occurrence of an abrupt wall structure change are the only properties closely correlated to the creep displacement characteristics of a planar wall in low dispersion films.

Effect of neutron irradiation on magnetic properties in the low alloy Ni-Mo steel SA508-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, D.G.; Kim, C.G.; Kim, H.C.

1997-04-01

The B-H hysteresis loop and Barkhausen noise have been measured in the neutron irradiated SA508 steel of 45 {mu}m thickness. The coercive force of B-H loop showed a slow change up to a neutron dose of 10{sup 14} n/cm{sup 2} and increased by 15.4{percent} for a 10{sup 16} n/cm{sup 2} dose sample compared with that of the unirradiated one, related to the domain wall motion hindered by the increased defects. However, the amplitude of Barkhausen noise reflecting the wall motion decreased slowly up to 10{sup 14} n/cm{sup 2} irradiation, followed by a rapid decrease of 37.5{percent} at 10{sup 16} n/cm{supmore » 2}. {copyright} {ital 1997 American Institute of Physics.}« less

Properties of epitaxial BaTiO{sub 3} deposited on GaAs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Contreras-Guerrero, R.; Droopad, R.; Veazey, J. P.

2013-01-07

Single crystal BaTiO{sub 3} (BTO) has been grown epitaxially on GaAs using molecular beam epitaxy with a 2 unit cell SrTiO{sub 3} nucleation layer. The oxide film is lattice-matched to GaAs through an in-plane rotation of 45 Degree-Sign relative to the (100) surface leading to c-axis orientation of the BaTiO{sub 3}. X-ray diffraction confirmed the crystallinity and orientation of the oxide film with a full width half maximum of 0.58 Degree-Sign for a 7.5 nm thick layer. Piezoresponse force microscopy was used to characterize the ferroelectric domains in the BaTiO{sub 3} layer, and a coercive voltage of 1-2 V andmore » piezoresponse amplitude {approx}5 pm/V was measured.« less

Israel Policy is Key to Defeating Islamic Extremists: A Coercive Solution to the Israeli-Palestinian Conflict

DTIC Science & Technology

2010-01-01

Israel Policy is Key to Defeating Islamic Extremists: A Coercive Solution to the Israeli-Palestinian Conflict Distribution A : Approved for...Unfortunately, continuation of the historical US position on the issue makes continuation of the conflict a dangerous national security risk to the US. This...paper will examine the conflict in light of US national security and propose that the current administration take a new approach to resolution in

Nuclear Weapons and Coercive Escalation in Regional Conflicts: Lessons from North Korea and Pakistan

DTIC Science & Technology

2014-11-01

brinkmanship relies on apparently suicidal and self-destructive tactics. Pakistan is often described as a country that “negotiates with a gun to its own...On 13 December 2001, five militants armed with plastic explosives, suicide vests, assault rifles, and grenades infiltrated the secure perimeter...is true, it is possible that the temptation to engage in coercive escalation will become tempered over time as relatively new nuclear powers come to

Paleomagnetism of late Quaternary drift sediments off the west Antarctica Peninsula

NASA Astrophysics Data System (ADS)

Channell, J. E. T.; Xuan, C.; Hillenbrand, C. D.; Larter, R. D.

2016-12-01

Natural remanant magnetization of a series of piston cores (typically 10 m in lengtth) collected during the JR298 Expedition (January-March 2015) to the west Antarctica Peninsula shows well-defined magnetic components (maximum angular deviations 1°-3°) that potentially record paleomagnetic changes at high southern latitudes. Rock magnetic experiments on the sediments conducted at room and high (up to 700°C) temperatures demonstrate the presence of a low- and a high-coercivity component (mean coercivity of 50-60 mT and 130-140 mT respectively). Paleomagnetic directions from the piston cores are primarily carried by the low-coercivity detrital (titano)magnetite, and are affected by authigenic growth of the high-coercivity maghemite. Maghematization in these sediments is attributed to the low concentrations of labile organic matter and lack of sulfate reduction in an extended oxic zone not penetrated by the piston cores. Despite the varying degree of maghematization, some of the recovered cores yield relative paleointensity (RPI) records that can be matched to a reference RPI record constructed mainly from North Atlantic cores. The resulting age models yield mean sedimentation rates of 4-12 cm/kyr for the JR298 piston cores. RPI may serve as a stratigraphic tool to date sediment cores from the region where traditional isotope stratigraphy is challenging due to the rarity of foraminiferal carbonate.

Regaining ownership and restoring belongingness: impact of family group conferences in coercive psychiatry.

PubMed

Meijer, Ellen; Schout, Gert; de Jong, Gideon; Abma, Tineke

2017-08-01

This study examined the impact of family group conferences on coercive treatment in adult psychiatry. Coercive treatment in psychiatry infringes the fundamental rights of clients, including the right to control their lives. A promising intervention is the family group conferences, which has the potential to prevent crises through the integration of the expertise of informal and professional networks. A responsive evaluation, including qualitative and quantitative methods, was deployed to study the process leading up to the FGC, the proceedings and the impact of the conference. From 2013-2015, 41 family group conferences were studied in three regions in the Netherlands. The impact of every conference was examined with scales (ranging from 0-10) during interviews with attendees (clients, family members, friends, mental health professionals and family group conferences coordinators) who reflected on three outcome measures: belongingness, ownership and coercion. After the family group conferences, respondents indicated a slight reduction in their experience of coercive treatment. They also mentioned an increase in ownership and belongingness. Family group conferences seems a promising intervention to reduce coercion in psychiatry. It helps to regain ownership and restores belongingness. If mental health professionals take a more active role in the pursuit of a family group conferences and reinforce the plans with their expertise, they can strengthen the impact even further. © 2017 John Wiley & Sons Ltd.

Validating the Construct of Coercion in Family Routines: Expanding the Unit of Analysis in Behavioral Assessment with Families of Children with Developmental Disabilities

PubMed Central

Lucyshyn, Joseph M.; Irvin, Larry K.; Blumberg, E. Richard; Laverty, Robelyn; Horner, Robert H.; Sprague, Jeffrey R.

2015-01-01

We conducted an observational study of parent-child interaction in home activity settings (routines) of families raising young children with developmental disabilities and problem behavior. Our aim was to empirically investigate the construct validity of coercion in typical but unsuccessful family routines. The long-term goal was to develop an expanded ecological unit of analysis that may contribute to sustainable behavioral family intervention. Ten children with autism and/or mental retardation and their families participated. Videotaped observations were conducted in typical but unsuccessful home routines. Parent-child interaction in routines was coded in real time and sequential analyses were conducted to test hypotheses about coercive processes. Following observation, families were interviewed about the social validity of the construct. Results confirmed the presence of statistically significant, attention-driven coercive processes in routines in which parents were occupied with non-child centered tasks. Results partially confirmed the presence of escape-driven coercive processes in routines in which parent demands are common. Additional analysis revealed an alternative pattern with greater magnitude. Family perspectives suggested the social validity of the construct. Results are discussed in terms of preliminary, partial evidence for coercive processes in routines of families of children with developmental disabilities. Implications for behavioral assessment and intervention design are discussed. PMID:26321883

Abnormal variation of magnetic properties with Ce content in (PrNdCe)2Fe14B sintered magnets prepared by dual alloy method

NASA Astrophysics Data System (ADS)

Xue-Feng, Zhang; Jian-Ting, Lan; Zhu-Bai, Li; Yan-Li, Liu; Le-Le, Zhang; Yong-Feng, Li; Qian, Zhao

2016-05-01

Resource-saving (PrNdCe)2Fe14B sintered magnets with nominal composition (PrNd)15-x Ce x Fe77B8 (x = 0-10) were prepared using a dual alloy method by mixing (PrNd)5Ce10Fe77B8 with (PrNd)15Fe77B8 powders. For Ce atomic percent of 1% and 2%, coercivity decreases dramatically. With further increase of Ce atomic percent, the coercivity increases, peaks at 6.38 kOe in (PrNd)11Ce4Fe77B8, and then declines gradually. The abnormal dependence of coercivity is likely related to the inhomogeneity of rare earth chemical composition in the intergranular phase, where PrNd concentration is strongly dependent on the additive amount of (PrNd)5Ce10Fe77B8 powders. In addition, for Ce atomic percent of 8%, 7%, and 6% the coercivity is higher than that of magnets prepared by the conventional method, which shows the advantage of the dual alloy method in preparing high abundant rare earth magnets. Project supported by the National Natural Science Foundation of China (Grant Nos. 51461033, 51571126, 51541105, and 11547032), the Natural Science Foundation of Inner Mongolia, China (Grant No. 2013MS0110), and the Inner Mongolia University of Science and Technology Innovation Fund, China.

Evolution of magnetic properties in the vicinity of the Verwey transition in Fe3O4 thin films

NASA Astrophysics Data System (ADS)

Liu, X. H.; Liu, W.; Zhang, Z. D.

2017-09-01

We have systematically studied the evolution of magnetic properties, especially the coercivity and the remanence ratio in the vicinity of the Verwey transition temperature (TV), of high-quality epitaxial Fe3O4 thin films grown on MgO (001), MgAl2O4 (MAO) (001), and SrTiO3 (STO) (001) substrates. We observed rapid change of magnetization, coercivity, and remanence ratio at TV, which are consistent with the behaviors of resistivity versus temperature [ρ (T )] curves for the different thin films. In particular, we found quite different magnetic behaviors for the thin films on MgO from those on MAO and STO, in which the domain size and the strain state play very important roles. The coercivity is mainly determined by the domain size but the demagnetization process is mainly dependent on the strain state. Furthermore, we observed a reversal of remanence ratio at TV with thickness for the thin films grown on MgO: from a rapid enhancement for 40-nm- to a sharp drop for 200-nm-thick film, and the critical thickness is about 80 nm. Finally, we found an obvious hysteretic loop of coercivity (or remanence ratio) with temperature around TV, corresponding to the hysteretic loop of the ρ (T ) curve, in Fe3O4 thin film grown on MgO.

Can “Model Projects of Need-Adapted Care” Reduce Involuntary Hospital Treatment and the Use of Coercive Measures?

PubMed Central

Wullschleger, Alexandre; Berg, Jürgen; Bermpohl, Felix; Montag, Christiane

2018-01-01

Intensive outpatient models of need-adapted psychiatric care have been shown to reduce the length of hospital stays and to improve retention in care for people with severe mental illnesses. In contrast, evidence regarding the impact of such models on involuntary hospital treatment and other coercive measures in inpatient settings is still sparse, although these represent important indicators of the patients' wellbeing. In Germany, intensive models of care still have not been routinely implemented, and their effectiveness within the German psychiatric system is only studied in a few pioneering regions. An innovative model of flexible, assertive, need-adapted care established in Berlin, Germany, in 2014, treating unselected 14% of the catchment area's patients, was evaluated on the basis of routine clinical data. Records of n = 302 patients diagnosed with severe mental disorders, who had been hospitalized at least once during a 4-year-observational period, were analyzed in a retrospective individual mirror-image design, comparing the 2 years before and after inclusion in the model project regarding the time spent in hospital, the number and duration of involuntary hospital treatments and the use of direct coercive interventions like restraint or isolation. After inclusion to the project, patients spent significantly less time in hospital. Among patients treated on acute wards and patients with a diagnosis of psychosis, the number of patients subjected to provisional detention due to acute endangerment of self or others decreased significantly, as did the time spent under involuntary hospital treatment. The number of patients subjected to mechanical restraint, but not to isolation, on the ward decreased significantly, while the total number of coercive interventions remained unchanged. Findings suggest some potential of intensive models of need-adapted care to reduce coercive interventions in psychiatry. However, results must be substantiated by evidence from randomized-controlled trials and longer observation periods. PMID:29765339

A 37,000-year environmental magnetic record of aeolian dust deposition from Burial Lake, Arctic Alaska

NASA Astrophysics Data System (ADS)

Dorfman, J. M.; Stoner, J. S.; Finkenbinder, M. S.; Abbott, M. B.; Xuan, C.; St-Onge, G.

2015-11-01

Environmental magnetism and radiocarbon dating of Burial Lake sediments constrain the timing and magnitude of regional aeolian deposition for the Noatak region of western Arctic Alaska for the last ∼37,000 years. Burial Lake (68.43°N, 159.17°W, 21.5 m water depth) is optimally located to monitor regional dust deposition because it is perched above local drainage and isolated from glacial processes. Cores collected in the summer of 2010 were studied through the application of magnetizations and progressive alternating field (AF) demagnetization of u-channel samples, with additional data provided by computed tomography (CT) derived density, hysteresis measurements, isothermal remanent magnetization (IRM) acquisition experiments, organic carbon content, biogenic silica, physical grain size, radiocarbon dating of wood, seeds, and plant macrofossils, point source magnetic susceptibility, and X-ray fluorescence (XRF). With similar magnetic properties to regional Alaskan loess deposits, low coercivity, highly magnetic material deposited during the late-Pleistocene contrasts with a high coercivity, weakly magnetic component found throughout the record, consistent with locally-derived detritus. The relative proportion of low coercivity to high coercivity magnetic material, defined by the S-Ratios, is used to reconstruct the regional input of dust to the basin over time. A four-fold decrease in the low coercivity component through the deglacial transition is interpreted to reflect diminished dust input to the region. Comparisons with potential sources of dust show that the timing of deposition in Burial Lake is largely consistent with general aridity, lack of vegetative cover, and increased windiness, rather than glacial advances or retreats. The influence from subaerial exposure of continental shelves cannot be ruled out as a significant far-field source of dust to interior Alaska during the Last Glacial Maximum (LGM), but is unlikely to have been the sole source, or to have contributed to increased dust in both the early and late Holocene.

Structural and magnetic properties of the products of the transformation of ferrihydrite: Effect of cobalt dications

NASA Astrophysics Data System (ADS)

Camacho, K. I.; Pariona, N.; Martinez, A. I.; Baggio-Saitovitch, E.; Herrera-Trejo, M.; Perry, Dale L.

2017-05-01

The effect of cobalt dications on the transformation of 2-line ferrihydrite (2LF) has been studied. The products of the transformation reaction were characterized by X-ray diffraction, Mössbauer spectroscopy (MS), transmission electron microscopy (TEM), magnetometry, and first-order reversal curve (FORC) diagrams. It was found that the concentration of cobalt dications plays an important role on the structural and magnetic properties of the products; i.e., for low cobalt concentrations, cobalt-substituted hematite is formed, while higher concentrations promote the formation of cobalt-substituted magnetite. Structural results revealed that formation of other iron oxide polymorphs is avoided and residual 2LF is always present in the final products. In this way, hematite/2LF and magnetite/2LF nanocomposites were formed. For all the samples, magnetic measurements yielded non-saturated hysteresis loops at a maximum field of 12 kOe. For cobalt-substituted hematite/2LF samples, FORC diagrams revealed the presence of multiple single-domain (SD) components which generate interaction coupling between SD with low and high coercivity. Moreover, for cobalt-substituted magnetite/2LF samples, the FORC diagrams revealed the components of wasp-waist hysteresis loops which consist of mixtures of SD and superparamagnetic particles. One of the goals of the present study is the rigorous, experimental documentation of ferrihydrite/hematite mixtures as a function of reaction conditions for use as analytical standards research.

The augmented Lagrangian method for parameter estimation in elliptic systems

NASA Technical Reports Server (NTRS)

Ito, Kazufumi; Kunisch, Karl

1990-01-01

In this paper a new technique for the estimation of parameters in elliptic partial differential equations is developed. It is a hybrid method combining the output-least-squares and the equation error method. The new method is realized by an augmented Lagrangian formulation, and convergence as well as rate of convergence proofs are provided. Technically the critical step is the verification of a coercivity estimate of an appropriately defined Lagrangian functional. To obtain this coercivity estimate a seminorm regularization technique is used.

Influence of cobalt doping on structural and magnetic properties of BiFeO3 nanoparticles

NASA Astrophysics Data System (ADS)

Khan, U.; Adeela, N.; Javed, K.; Riaz, S.; Ali, H.; Iqbal, M.; Han, X. F.; Naseem, S.

2015-11-01

Nanocrystalline cobalt-doped bismuth ferrites with general formula of BiFe1- δ Co δ O3 (0 ≤ δ ≤ 0.1) have been synthesized using solution evaporation method. Structure and phase identification was performed with X-ray diffraction (XRD) technique. The results confirm the formation of rhombohedral-distorted Perovskite structure with R3c symmetry. A decrease in lattice parameters and an increase in X-ray density have been observed with increasing cobalt concentration in BiFeO3. Particle size determined by transmission electron microscope was in good agreement with XRD, i.e., 39 nm. Room-temperature coercivity and saturation magnetization of nanoparticles were increased up to 7.5 % of cobalt doping. Low-temperature magnetic measurements of selected sample showed increasing behavior in saturation magnetization, coercivity, effective magnetic moments, and anisotropy constant. An increase in coercivity with decrease in temperature followed theoretical model of Kneller's law, while modified Bloch's model was employed for saturation magnetization in temperature range of 5-300 K.

Anisotropy of the ferromagnetic L10 phase in the Mn-Al-C alloys induced by high-pressure spark plasma sintering

NASA Astrophysics Data System (ADS)

Tyrman, Muriel; Ahmim, Smail; Pasko, Alexandre; Etgens, Victor; Mazaleyrat, Frédéric; Quetel-Weben, Simon; Perrière, Loïc; Guillot, Ivan

2018-05-01

The metastable τ-phase of MnAl equi-atomic compound belongs to a family of ferromagnetic alloys with L10 crystal structure. Stabilization of the phase by adding 2 at. % using manganese carbide (Mn23C6) enhances the magnetization in relation with the increase in lattice volume. It is thus a promising candidate for rare-earth-free permanent magnets. Coercivity of Mn-Al-C alloys being still weak, there is an interest to see to which extend sintering/transformation of the ɛ-phase by Spark Plasma Sintering (SPS) can increase the coercivity and the anisotropy. The structural and the magnetic properties were studied for samples sintered at 550 °C under uniaxial pressure of 100, 200, 300 and 400 MPa. Coercivity, remanence and anistotropy appears with the sintering pressure. The high pressure applied while sintering produces preferential orientation of the flake-shaped grains which influences the remanence.

Micromagnetics of rare-earth efficient permanent magnets

NASA Astrophysics Data System (ADS)

Fischbacher, Johann; Kovacs, Alexander; Gusenbauer, Markus; Oezelt, Harald; Exl, Lukas; Bance, Simon; Schrefl, Thomas

2018-05-01

The development of permanent magnets containing less or no rare-earth elements is linked to profound knowledge of the coercivity mechanism. Prerequisites for a promising permanent magnet material are a high spontaneous magnetization and a sufficiently high magnetic anisotropy. In addition to the intrinsic magnetic properties the microstructure of the magnet plays a significant role in establishing coercivity. The influence of the microstructure on coercivity, remanence, and energy density product can be understood by using micromagnetic simulations. With advances in computer hardware and numerical methods, hysteresis curves of magnets can be computed quickly so that the simulations can readily provide guidance for the development of permanent magnets. The potential of rare-earth reduced and rare-earth free permanent magnets is investigated using micromagnetic simulations. The results show excellent hard magnetic properties can be achieved in grain boundary engineered NdFeB, rare-earth magnets with a ThMn12 structure, Co-based nano-wires, and L10-FeNi provided that the magnet’s microstructure is optimized.

Investigation of fatigue behavior of Pb(Zr0.45Ti0.55)O3 thin films under asymmetric polarization switching

NASA Astrophysics Data System (ADS)

Zhu, Hui; Chen, Yueyuan; Chu, Daping; Feng, Shiwei; Zhang, Yingqiao; Wang, Pengfei

2016-09-01

The fatigue of lead zirconate titanate (PZT) thin films was measured under repetitive switching using asymmetric square waves. The remnant polarization and coercive voltage were found to present regular changes in the initial 10 s, independent of the asymmetry or frequency of switching waves. We attributed the change to the relaxation of stress in the film and identified a coercive voltage V 0 of 0.6 V for the stress-free film. By comparing the coercive voltage and V 0, we found that a built-in electric field was induced by asymmetric switching, where the direction and magnitude were dependent on the degree of waveform asymmetry. Furthermore, the fatigue speed was suggested to be closely related to the generation rate of oxygen vacancies. It was confirmed by our result that a faster decay of remnant polarization can be obtained by applying square waves with a higher degree of asymmetry or symmetry of square waves with a lower frequency.

Enhancement of the coercivity in Co-Ni layered double hydroxides by increasing basal spacing.

PubMed

Zhang, Cuijuan; Tsuboi, Tomoya; Namba, Hiroaki; Einaga, Yasuaki; Yamamoto, Takashi

2016-09-14

The magnetic properties of layered double hydroxides (LDH) containing transition metal ions can still develop, compared with layered metal hydroxide salts which exhibit structure-dependent magnetism. In this article, we report the preparation of a hybrid magnet composed of Co-Ni LDH and n-alkylsulfonate anions (Co-Ni-CnSO3 LDH). As Co-Ni LDH is anion-exchangeable, we can systematically control the interlayer spacing by intercalating n-alkylsulfonates with different carbon numbers. The magnetic properties were examined with temperature- and field-dependent magnetization measurements. As a result, we have revealed that the coercive field depends on the basal spacing. It is suggested that increasing the basal spacing varies the competition between the in-plane superexchange interactions and long-range out-of-plane dipolar interactions. Moreover, a jump in the coercive field at around 20 Å of the basal spacing is assumed to be the modification of the magnetic ordering in Co-Ni-CnSO3 LDH.

Improved thermal stability of TbF3-coated sintered Nd-Fe-B magnets by electrophoretic deposition

NASA Astrophysics Data System (ADS)

Cao, X. J.; Chen, L.; Guo, S.; Di, J. H.; Ding, G. F.; Chen, R. J.; Yan, A. R.; Chen, K. Z.

2018-05-01

Using electrophoretic deposition (EPD) method, the impact of TbF3 diffusion on the coercivity, microstructure and thermal stability of sintered Nd-Fe-B magnets with different rare earth (RE) content was investigated. In the diffused magnets with the RE content of 34 wt.%, the maximum coercivity about 28.12 kOe with less than 1.44 wt.% Tb was achieved, the coercivity temperature coefficient (β) was improved to -0.50 %/°C from -0.58 %/°C within the temperature interval 25-160 °C, and the maximum operating temperature further increased to about 160 °C. It suggested that TbF3 diffused magnets had much superior thermal stability than the annealed samples. This was attributed to the formation of the Tb-rich (Nd, Tb)2Fe14B phase in the outer region of the matrix grains and the improved Nd-rich grain boundary phase after TbF3 diffusion.

Influence of the divalent and trivalent ions substitution on the structural and magnetic properties of Mg0.5-xCdxCo0.5Cr0.04TbyFe1.96-yO4 ferrites prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Mustafa, Ghulam; Islam, M. U.; Zhang, Wenli; Anwar, Abdul Waheed; Jamil, Yasir; Murtaza, Ghulam; Ali, Ihsan; Hussain, Mudassar; Ali, Akbar; Ahmad, Mukhtar

2015-08-01

A series of the divalent and trivalent co-substituted Mg0.5-xCdxCo0.5Cr0.04TbyFe1.96-yO4 spinel ferrite systems (where x=0-0.5 in steps of 0.1 and y=0.00-0.10 in steps 0.02) are synthesized by sol-gel auto combustion method. The product materials were characterized by the thermo gravimetric analysis and differential scanning calorimetry (TGA/DSC), Fourier transform infrared spectra (FTIR), nitrogen adsorption (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The X-ray diffraction patterns and Fourier transform infrared spectroscopy confirm spinel nanocrystalline phase. The crystallite size is determined by Scherer's formula from 36.6 to 69.4 nm. The X-ray density is found in the range of 5.09-6.43 (g/cm3). The morphological features are studied using scanning electron microscope and AFM. Saturation magnetization (Ms) and remanence (Mr) magnetization extracted from M-H loops exhibit the decreasing trends 21.4-16 emu/g and 9.1-6.3 emu/g, respectively. A significant decrease in the intrinsic parameters is observed in the prepared samples due to the weakening of the A-B interaction as iron enters into the tetrahedral A-site. The coercivity lies in the range of 300-869 Oe as a function of co-substitution contents. The coercivity of the sample with x=0.1, y=0.02 was found maximum i.e. 869 Oe. The obtained results suggest that the investigated materials may be potential candidates for high density recording media applications.

Study of ion beam sputtered Fe/Si interfaces as a function of Si layer thickness

NASA Astrophysics Data System (ADS)

Kumar, Anil; Brajpuriya, Ranjeet; Singh, Priti

2018-01-01

The exchange interaction in metal/semiconductor interfaces is far from being completely understood. Therefore, in this paper, we have investigated the nature of silicon on the Fe interface in the ion beam deposited Fe/Si/Fe trilayers keeping the thickness of the Fe layers fixed at 3 nm and varying the thickness of the silicon sandwich layer from 1.5 nm to 4 nm. Grazing incidence x-ray diffraction and atomic force microscopy techniques were used, respectively, to study the structural and morphological changes in the deposited films as a function of layer thickness. The structural studies show silicide formation at the interfaces during deposition and better crystalline structure of Fe layers at a lower spacer layer thickness. The magnetization behavior was investigated using magneto-optical Kerr effect, which clearly shows that coupling between the ferromagnetic layers is highly influenced by the semiconductor spacer layer thickness. A strong antiferromagnetic coupling was observed for a value of tSi = 2.5 nm but above this value an unexpected behavior of hysteresis loop (step like) with two coercivity values is recorded. For spacer layer thickness greater than 2.5 nm, an elemental amorphous Si layer starts to appear in the spacer layer in addition to the silicide layer at the interfaces. It is observed that in the trilayer structure, Fe layers consist of various stacks, viz., Si doped Fe layers, ferromagnetic silicide layer, and nonmagnetic silicide layer at the interfaces. The two phase hysteresis loop is explained on the basis of magnetization reversal of two ferromagnetic layers, independent of each other, with different coercivities. X-ray photo electron spectroscopy technique was also used to study interfaces characteristics as a function of tSi.

Nanosphere lithography applied to magnetic thin films

NASA Astrophysics Data System (ADS)

Gleason, Russell

Magnetic nanostructures have widespread applications in many areas of physics and engineering, and nanosphere lithography has recently emerged as promising tool for the fabrication of such nanostructures. The goal of this research is to explore the magnetic properties of a thin film of ferromagnetic material deposited onto a hexagonally close-packed monolayer array of polystyrene nanospheres, and how they differ from the magnetic properties of a typical flat thin film. The first portion of this research focuses on determining the optimum conditions for depositing a monolayer of nanospheres onto chemically pretreated silicon substrates (via drop-coating) and the subsequent characterization of the deposited nanosphere layer with scanning electron microscopy. Single layers of permalloy (Ni80Fe20) are then deposited on top of the nanosphere array via DC magnetron sputtering, resulting in a thin film array of magnetic nanocaps. The coercivities of the thin films are measured using a home-built magneto-optical Kerr effect (MOKE) system in longitudinal arrangement. MOKE measurements show that for a single layer of permalloy (Py), the coercivity of a thin film deposited onto an array of nanospheres increases compared to that of a flat thin film. In addition, the coercivity increases as the nanosphere size decreases for the same deposited layer. It is postulated that magnetic exchange decoupling between neighboring nanocaps suppresses the propagation of magnetic domain walls, and this pinning of the domain walls is thought to be the primary source of the increase in coercivity.

Staff's attitudes and reactions towards aggressive behaviour of clients with intellectual disabilities: a multi-level study.

PubMed

Knotter, Maartje H; Wissink, Inge B; Moonen, Xavier M H; Stams, Geert-Jan J M; Jansen, Gerard J

2013-05-01

Data were collected from 121 staff members (20 direct support staff teams) on background characteristics of the individual staff members and their teams (gender, age, years of work experience, position and education), the frequency and form of aggression of clients with an intellectual disability (verbal or physical), staff members' attitudes towards aggression, and the types of behavioural interventions they executed (providing personal space and behavioural boundary-setting, restricting freedom and the use of coercive measures). Additionally, client group characteristics (age of clients, type of care and client's level of intellectual disability) were assessed. Multilevel analyses (individual and contextual level) were performed to examine the relations between all studied variables and the behavioural interventions. The results showed that for providing personal space and behavioural boundary-setting as well as for restricting freedom, the proportion of variance explained by the context (staff team and client group characteristics) was three times larger than the proportion of variance explained by individual staff member characteristics. For using coercive measures, the context even accounted for 66% of the variance, whereas only 8% was explained by individual staff member characteristics. A negative attitude towards aggression of the direct support team as a whole proved to be an especially strong predictor of using coercive measures. To diminish the use of coercive measures, interventions should therefore be directed towards influencing the attitude of direct support teams instead of individual staff members. Copyright © 2013 Elsevier Ltd. All rights reserved.

Magnetic properties of the ammonolysis product of α-Fe powder containing a small amount of aluminum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsugawa, Yuta; Maubuchi, Yuji; Motohashi, Teruki

2015-02-15

Magnetite was prepared containing a small amount of aluminum and its nitride was generated through low temperature ammonolysis following reduction under hydrogen. The nitrided product was determined by XRD to be a mixture of “α″-Fe{sub 16}N{sub 2}” having a slightly deformed crystal structure from α″-Fe{sub 16}N{sub 2} and the residual α-Fe. Magnetic coercivity of the mixture was decreased from the value of 150 mT obtained for the nitride product made without aluminum, due to the precipitation of nonmagnetic amorphous alumina in the low temperature nitrided bcc (Fe{sub 1−x}Al{sub x}) with x≤0.03. The aluminum-doped nitride product in which the “α″-Fe{sub 16}N{submore » 2}” fraction was 30 at% exhibited magnetization at 1.5 T of approximately 200 Am{sup 2}kg{sup −1} at room temperature and its magnetic coercivity was 20 mT. - Graphical abstract: Magnetic iron nitride particles were separated by nonmagnetic amorphous γ-alumina. Magnetic coercivity was decreased by reducing the magnetic interaction between the particles. - Highlights: • Magnetic coercivity decreased in α”-Fe{sub 16}N{sub 2} like compound as a soft magnet. • Small amount of Al addition was effective in its preparation. • Magnetic interaction decreased between the “α”-Fe{sub 16}N{sub 2}” particles.« less

Magnetic and microstructural investigation of high-coercivity net-shape Nd-Fe-B-type magnets produced from spark-plasma-sintered melt-spun ribbons blended with DyF3

NASA Astrophysics Data System (ADS)

Žagar, Kristina; Kocjan, Andraž; Kobe, Spomenka

2016-04-01

Nanostructured Nd-Fe-B-type materials produced by melt-spinning (MS) are used in a variety of applications in the electronics, automotive, and sensor industries. The very rapid MS process leads to flake-like powders with metastable, nanoscale, Nd2Fe14B grains. These powders are then formed into net-shaped, isotropic, polymer-bonded magnets, or they are hot formed into fully dense, metallic magnets that are isotropic and anisotropic. These fully dense magnets are usually produced with a conventional hot press without the inclusion of additives prior to the hot pressing. As a result, their properties, particularly the coercivity (Hci), are insufficient at automotive-relevant temperatures of 100-150 °C since the material Hci has a large temperature coefficient. In this study, we instead add a thin layer of DyF3 to the melt-spun ribbons prior to their hot consolidation in order to enhance the coercivity through a diffusion-based, partial substitution of the Nd by Dy. This is accomplished by applying extremely rapid, spark-plasma sintering to minimize any growth of the nanoscale Nd2Fe14B grains during consolidation. The result is a very high-coercivity magnet with drastically reduced amounts of heavy rare earths that is suitable for high-temperature applications. This work clearly demonstrates how rapidly formed, metastable states can provide us with properties that are unobtainable with conventional techniques.

Magnetic properties and coercivity mechanism of Sm{sub 1-x}Pr{sub x}Co{sub 5} (x=0-0.6) nanoflakes prepared by surfactant-assisted ball milling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, M. L.; Yue, M., E-mail: yueming@bjut.edu.cn; Wu, Q.

2016-05-15

Sm{sub 1-x}Pr{sub x}Co{sub 5} (x=0-0.6) nanoflakes with CaCu{sub 5} structure were successfully prepared by surfactant-assisted high-energy ball milling (SAHEBM). The crystal structure and magnetic properties of Sm{sub 1-x}Pr{sub x}Co{sub 5} (x=0-0.6) nanoflakes were studied by X-ray diffraction and vibrating sample magnetometer. Effects of Pr addition on the structure, magnetic properties and coercivity mechanism of Sm{sub 1-x}Pr{sub x}Co{sub 5} nanoflakes were systematically investigated. XRD results show that all the nanoflakes have a hexagonal CaCu{sub 5}-type (Sm, Pr){sub 1}Co{sub 5} main phase and the (Sm, Pr){sub 2}Co{sub 7} impurity phase, and all of the samples exhibit a strong (00l) texture after magneticmore » alignment. As the Pr content increases, remanence firstly increases, then slightly reduced, while anisotropy field (H{sub A}) and H{sub ci} of decrease monotonically. Maximum energy product [(BH){sub max}] of the flakes increases first, peaks at 24.4 MGOe with Pr content of x = 0.4, then drops again. Magnetization behavior analysis indicate that the coercivity mechanism is mainly controlled by inhomogeneous domain wall pinning, and the pinning strength weakens with the increased Pr content, suggesting the great influence of H{sub A} on the coercivity of flakes.« less

Influence of dipolar interactions on the angular-dependent coercivity of nickel nanocylinders

NASA Astrophysics Data System (ADS)

Bender, P.; Krämer, F.; Tschöpe, A.; Birringer, R.

2015-04-01

In this study the influence of dipolar interactions on the orientation-dependent magnetization behavior of an ensemble of single-domain nickel nanorods was investigated. The rods were synthesized by electrodeposition of nickel into porous alumina templates. Some of the rods were released from the oxide and embedded in gelatine hydrogels (ferrogel) at a sufficiently large average interparticle distance to suppress dipolar interactions. By comparing the orientation-dependent hystereses of the two ensembles in the template and the gel-matrix it could be shown that the dipolar interactions in the template considerably alter the functional form of the angular-dependent coercivity. Analysis of the magnetization curves for an angle of 60° between the rod-axes and the field revealed a significantly reduced coercivity of the template compared to the ferrogel, which could be directly attributed to a stray field induced magnetization reversal of a steadily increasing number of rods with increasing field strength. The magnetization curve of the template could be approximated by a weighted linear superposition of the hysteresis branches of the ferrogel. The magnetization reversal process of the rods was investigated by analyzing the angular-dependent coercivity of the non-interacting nanorods. Comparison of the functional form with analytical models and micromagnetic simulations emphasized the assumption of a localized magnetization reversal. Additionally, it could be shown that the nucleation field of rods with diameters in the range 18-29 nm tends to increase with increasing diameter.

Ion irradiation induced effects and magnetization reversal mechanism in (Ni80Fe20)1-xCox nanowires and nanotubes

NASA Astrophysics Data System (ADS)

Ahmad, Naeem; Iqbal, Javed; Chen, J. Y.; Hussain, Asim; Shi, D. W.; Han, X. F.

2015-03-01

The effect of Co on the ferromagnetic characteristics of the Ni80Fe20 nanocylinders having zero magnetostriction and soft magnetic nature is an interesting field of research. The (Ni80Fe20)1-xCox nanocylinders have been prepared by electrodeposition into commercially available anodized aluminum oxide (AAO) nanoporous templates. The analysis of magnetization reversal from the angular dependence of coercivity has been studied in detail. This angular dependence of coercivity has shown a transition from curling to nucleation mode as a function of field angle for all (Ni80Fe20)1-xCox nanocylinders depending upon the critical angle. The shape anisotropy, dipole-dipole interactions, surface effects and magnetocrystalline anisotropy have been found to play an effective role for the spontaneous magnetization in nanowires and nanotubes. It has been interestingly observed that the magnetostatic interactions or dipole-dipole interactions are dominant in nanocylinders regardless of its geometry. Furthermore, the prepared samples have been irradiated with He2+ ions (energy E=2 MeV, fluence=1014 ions/cm2 and ion current=16 nA) at room temperature using a 5-UDH-2pelletron tandem accelerator. The irradiations have created defects and these defects have induced changes in magnetization as a result an increase in coercivity as function of the ion fluences is observed. Such kind of behavior in coercivity enhancement and magnetization reduction can also be attributed to the stress relaxation and percolation in nonuniform states of ferromagnetic alloys, respectively.

Experimental mixtures of superparamagnetic and single-domain magnetite with respect to Day-Dunlop plots

NASA Astrophysics Data System (ADS)

Kumari, Monika; Hirt, Ann M.; Uebe, Rene; Schüler, Dirk; Tompa, Éva; Pósfai, Mihály; Lorenz, Wolfram; Ahrentorp, Fredrik; Jonasson, Christian; Johansson, Christer

2015-06-01

Day-Dunlop plots are widely used in paleomagnetic and environmental studies as a tool to determine the magnetic domain state of magnetite, i.e., superparamagnetic (SP), stable single-domain (SD), pseudosingle-domain (PSD), multidomain (MD), and their mixtures. The few experimental studies that have examined hysteresis properties of SD-SP mixtures of magnetite found that the ratios of saturation remanent magnetization to saturation magnetization and the coercivity of remanence to coercivity are low, when compared to expected theoretical mixing trends based on Langevin theory. This study reexamines Day-Dunlop plots using experimentally controlled mixtures of SD and SP magnetite grains. End-members include magnetotactic bacteria (MSR-1) as the SD source, and a commercial ferrofluid or magnetotactic bacteria (ΔA12) as the SP source. Each SP-component was added incrementally to a SD sample. Experimental results from these mixing series show that the magnetization and coercivity ratios are lower than the theoretical prediction for bulk SP magnetic size. Although steric repulsion was present between the particles, we cannot rule out interaction in the ferrofluid for higher concentrations. The SP bacteria are noninteracting as the magnetite was enclosed by an organic bilipid membrane. Our results demonstrate that the magnetization and coercivity ratios of SD-SP mixtures can lie in the PSD range, and that an unambiguous interpretation of particle size can only be made with information about the magnetic properties of the end-members.

High coercivity Gd-substituted Ba hexaferrites, prepared by chemical coprecipitation

NASA Astrophysics Data System (ADS)

Litsardakis, G.; Manolakis, I.; Serletis, C.; Efthimiadis, K. G.

2008-04-01

A series of Gd-substituted Ba hexaferrites with nominal formula (Ba1-xGdx)Oṡ5.25 Fe2O3 (x=0-0.30) were prepared by the chemical coprecipitation method from nitrate precursors and heating at T =800-1200°C for 2h. The samples have been examined by x-ray diffraction, vibrating-sample magnetometer, and scanning electron microscopy methods. Gd substituted samples form single phase materials with the M-type hexaferrite structure at all heating temperatures, in the range of x ⩽0.10-0.20. The saturation magnetization (at 1.8T) varies slightly with x in most cases and, for x =0.05-0.10, it increases up to 66.7Am2/kg, exceeding the value of the unsubstituted hexaferrite. A strong enhancement of the coercivity is observed for all substituted samples, with maximum values Hc=457kA/m for the single-phase x =0.10 sample annealed at 1000°C and Hc=477kA/m for the x =0.25 sample annealed at 1100°C which contains Fe2O3 and GdFeO3 impurities. As the variation of coercivity with either substitution rate (x ) or annealing temperature is not monotonic, three different factors may account for the high coercivities that are obtained: (a) an inhibition of grain growth due to the presence of Gd, (b) a possible inherent effect on magnetocrystalline anisotropy, especially for single phase samples, and (c) a microstructural effect of secondary phases.

Coercivity enhancement mechanism in Dy-substituted Nd-Fe-B nanoparticles synthesized by sol-gel base method followed by a reduction-diffusion process

NASA Astrophysics Data System (ADS)

Rahimi, Hamed; Ghasemi, Ali; Mozaffarinia, Reza; Tavoosi, Majid

2017-05-01

In current work, Nd15-xDyxFe77.5B7.5 (at%) nanoparticles with different Dy-content (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized by sol-gel method followed by a reduction-diffusion process. The effects of Dy on the magnetic properties and the relations between the microstructure and the coercivity of Dy-substituted Nd-Fe-B nanoparticles have been studied. The coercivity of Nd-Fe-B nanoparticles with the addition of Dy first increase, reaches a maximum, and then starts to decrease. The coercivity of Dy-substituted Nd-Fe-B nanoparticle synthesized by sol-gel method increased from 938.9 to 1663.9 kA/m while the remanence decreased slightly from 1.16 to 1.06 T. The results show that with an increase in Dy content the variation of maximum energy product ((BH)max), lowest-order uniaxial magnetocrystalline anisotropy constant (Ku1), and Curie temperature (Tc) had a trend as same as the coercivity. The Henkel plot showed that the existence of exchange coupling interaction between grains, and the exchange coupling interactions increased with increasing x from 0.0 to 2.0 and then decrease with further increasing x≥2.5. The optimum magnetic properties of Nd-Fe-B nanoparticles with (BH)max =40.38 MGOe, Hc=1663.9 kA/m, Br=1.08 T were obtained by substituted 2.0 at% Dy. The effects of increasing temperature on magnetic properties of Dy-substituted Nd-Fe-B nanoparticle magnets with 2.0 at% Dy was investigated. The reduced spin-reorientation temperature was obtained for Dy-substituted Nd-Fe-B nanoparticles with 2.0 at% Dy. Below 100 K a spin-reorientation transition was takes place. The temperature coefficient of coercivity (β) was -0.36, -0.46, -0.41, -0.34, -0.29, -0.24, -0.25%/°C at different temperature 50, 100, 150, 200, 250, 300, 350 °C, respectively. Mössbauer spectroscopy was applied to study the composition and properties of Dy-substituted Nd-Fe-B magnet. Microstructure analysis showed a homogeneous distribution of Dy in produced samples. The possible reason for observed magnetic behavior is improving the intrinsic material parameter and optimizing the microstructure by a uniform enhancement of magnetocrystalline anisotropy by formation the nanocrystalline compound (Nd,Dy)2Fe14B.

Hysteresis in single and polycrystalline iron thin films: Major and minor loops, first order reversal curves, and Preisach modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Yue; Xu, Ke; Jiang, Weilin

Hysteretic behavior was studied in a series of Fe thin films, grown by molecular beam epitaxy, having different grain sizes and grown on different substrates. Major and minor loops and first order reversal curves (FORCs) were collected to investigate magnetization mechanisms and domain behavior under different magnetic histories. The minor loop coefficient and major loop coercivity increase with decreasing grain size due to higher defect concentration resisting domain wall movement. First order reversal curves allowed estimation of the contribution of irreversible and reversible susceptibilities and switching field distribution. The differences in shape of the major loops and first order reversalmore » curves are described using a classical Preisach model with distributions of hysterons of different switching fields, providing a powerful visualization tool to help understand the magnetization switching behavior of Fe films as manifested in various experimental magnetization measurements.« less

Preparation of high magneto-optical performance and crystalline quality Ce1Gd2Fe5-xGaxO12 films on CLNGG substrate crystal

NASA Astrophysics Data System (ADS)

Fu, Qiu-ping; Zheng, Ze-yuan; Lin, Nan-xi; Liu, Xiao-feng; Hong, Can-huang; Hu, Xiao-lin; Zhuang, Nai-feng; Chen, Jian-zhong

2016-11-01

Thin films of Ce1Gd2Fe5-xGaxO12 (Ce,Ga:GIG) were prepared on Gd3Ga5O12 (GGG) and Ca2.90Li0.30Nb1.93Ga2.76O12 (CLNGG) substrates by using radio frequency magnetron sputtering technique. The phase, grain orientation, surface morphology, transmittance, magnetism and magnetic circular dichroism (MCD) properties of films were analyzed. And the effects of lattice mismatch and non-magnetic Ga3+-doping were discussed. The results show that the films with higher crystallized quality and lower stress can be obtained by growing on CLNGG than on GGG. Moreover, the coercive force, magnetization, magneto-optical effect intensity and orientation of film can be effectively regulated by adjusting Ga3+-doped concentration.

Re-exchange of Fe and Cu at the interface in sintered Nd-Fe-B magnets: A method to eliminate Fe precipitation at grain boundaries

NASA Astrophysics Data System (ADS)

Yang, YuQi; Si, HengGang; Yang, Hao; Zhang, Lan; Huang, DongFang; Chen, BaiYi; Xu, Fang; Hu, YongMei; Han, BaoJun

2018-01-01

According to the decoupling hypothesis for magnetic grains, the coercivity in sintered Nd-Fe-B magnets is increased after Cu doping, which is due to the formation of non-magnetic grain boundaries. However, this method partially fails, and ferromagnetic Fe-segregation occurs at the grain boundary. We discovered both experimentally and through calculation that the Fe content at the grain boundaries can be tuned across a wide range by introducing another element of Ag. Segregated Fe at high temperature at the grain boundary re-dissolves into Nd2Fe14B grains during annealing at low temperature. Both configurable and magnetic entropies contribute a large driving force for the formation of nonmagnetic grain boundaries. Almost zero Fe content could be achieved at the grain boundaries of sintered Nd-Fe-B magnet.

Permanent-magnet multipole with adjustable strength

DOEpatents

Halbach, K.

1982-09-20

Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling there between. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

Permanent magnet multipole with adjustable strength

DOEpatents

Halbach, Klaus

1985-01-01

Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling therebetween. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

Hysteresis in single and polycrystalline iron thin films: Major and minor loops, first order reversal curves, and Preisach modeling

DOE PAGES

Cao, Yue; Xu, Ke; Jiang, Weilin; ...

2015-07-03

Hysteretic behavior was studied in a series of Fe thin films, grown by molecular beam epitaxy, having different grain sizes and grown on different substrates. Major and minor loops and first order reversal curves (FORCs) were collected to investigate magnetization mechanisms and domain behavior under different magnetic histories. The minor loop coefficient and major loop coercivity increase with decreasing grain size due to higher defect concentration resisting domain wall movement. First order reversal curves allowed estimation of the contribution of irreversible and reversible susceptibilities and switching field distribution. The differences in shape of the major loops and first order reversalmore » curves are described using a classical Preisach model with distributions of hysterons of different switching fields, providing a powerful visualization tool to help understand the magnetization switching behavior of Fe films as manifested in various experimental magnetization measurements.« less

The exchange interaction effects on magnetic properties of the nanostructured CoPt particles

NASA Astrophysics Data System (ADS)

Komogortsev, S. V.; Iskhakov, R. S.; Zimin, A. A.; Filatov, E. Yu.; Korenev, S. V.; Shubin, Yu. V.; Chizhik, N. A.; Yurkin, G. Yu.; Eremin, E. V.

2016-03-01

Various manifestations of the exchange interaction effects in magnetization curves of the CoPt nanostructured particles are demonstrated and discussed. The inter-grain exchange constant A in the sponge-like agglomerates of crystallites is estimated as A=(7±1) pJ/m from the approach magnetization to saturation curves that is in good agreement with A=(6.6±0.5) pJ/m obtained from Bloch T 3/2 law. The fractal dimensionality of the exchange coupled crystallite system in the porous media of the disordered CoPt alloy d=(2.60±0.18) was estimated from the approach magnetization to saturation curve. Coercive force decreases with temperature as Hc T 3/2 which is assumed to be a consequence of the magnetic anisotropy energy reduction due to the thermal spin wave excitations in the investigated CoPt particles.

"Restricted Community Members": Research Protections and Opportunities for Individuals Committed to Assisted Outpatient Treatment.

PubMed

Segal, Andrea G; Sisti, Dominic A

2017-02-01

Several forms of mandated community treatment exist in the United States. One mechanism, assisted outpatient treatment (AOT), has become both more common and more controversial in recent years. The status of individuals committed to AOT remains unclear within regulatory guidelines aimed at protecting research participants. Should individuals on AOT be considered psychiatric inpatients, prisoners, community members, or something else? The authors argue that persons on AOT inhabit a gray area wherein they should be given some of the ethical protections afforded to involuntary inpatients and prisoners, but they should also enjoy freedoms as members of the community. The authors' term for this population is "restricted community members." The need to protect individuals in this population from potentially coercive forces of AOT while also offering them the opportunity to participate in research is especially acute in areas of research where the need is great: serious mental illness and substance use disorders.

Strong correlation between early stage atherosclerosis and electromechanical coupling of aorta

NASA Astrophysics Data System (ADS)

Liu, X. Y.; Yan, F.; Niu, L. L.; Chen, Q. N.; Zheng, H. R.; Li, J. Y.

2016-03-01

Atherosclerosis is the underlying cause of cardiovascular diseases that are responsible for many deaths in the world, and the early diagnosis of atherosclerosis is highly desirable. The existing imaging methods, however, are not capable of detecting the early stage of atherosclerosis development due to their limited spatial resolution. Using piezoresponse force microscopy (PFM), we show that the piezoelectric response of an aortic wall increases as atherosclerosis advances, while the stiffness of the aorta shows a less evident correlation with atherosclerosis. Furthermore, we show that there is strong correlation between the coercive electric field necessary to switch the polarity of the artery and the development of atherosclerosis. Thus by measuring the electromechanical coupling of the aortic wall, it is possible to probe atherosclerosis at the early stage of its development, not only improving the spatial resolution by orders of magnitude, but also providing comprehensive quantitative information on the biomechanical properties of the artery.

Feasibility of low-cost magnetic rail designs by integrating ferrite magnets and NdFeB magnets for HTS Maglev systems

NASA Astrophysics Data System (ADS)

Sun, R. X.; Deng, Z. G.; Gou, Y. F.; Li, Y. J.; Zheng, J.; Wang, S. Y.; Wang, J. S.

2015-09-01

Permanent magnet guideway (PMG) is an indispensable part of high temperature superconducting (HTS) Maglev systems. Present PMGs are made of NdFeB magnets with excellent performance and cost much. As another permanent magnet material, the ferrite magnet is weak at magnetic energy product and coercive force, but inexpensive. So, it is a possible way to integrate the ferrite and NdFeB magnets for cutting down the cost of present PMGs. In the paper, the equivalent on magnetic field intensity between ferrite magnets and NdFeB magnets was evaluated by finite element simulation. According to the calculation results, the magnetic field of the PMG integrating ferrite magnets and NdFeB magnets can be increased remarkably comparing with the pure ferrite PMG. It indicates that low-cost PMG designs by integrating the two permanent magnet materials are feasible for the practical HTS Maglev system.

A magnetostatic-coupling based remote query sensor for environmental monitoring

NASA Technical Reports Server (NTRS)

Grimes, C. A.; Stoyanov, P. G.; Liu, Y.; Tong, C.; Ong, K. G.; Loiselle, K.; Shaw, M.; Doherty, S. A.; Seitz, W. R.

1999-01-01

A new type of in situ, remotely monitored magnetism-based sensor is presented that is comprised of an array of magnetically soft, magnetostatically-coupled ferromagnetic thin-film elements or particles combined with a chemically responsive material that swells or shrinks in response to the analyte of interest. As the chemically responsive material changes size the distance between the ferromagnetic elements changes, altering the inter-element magnetostatic coupling. This in turn changes the coercive force of the sensor, the amplitude of the voltage spikes detected in nearby pick-up coils upon magnetization reversal and the number of higher-order harmonics generated by the flux reversal. Since the sensor is monitored through changes in magnetic flux, no physical connections such as wires or cables are needed to obtain sensor information, nor is line of sight alignment required as with laser telemetry; the sensors can be detected from within sealed, opaque or thin metallic enclosures.

Prevalence and meanings of exchange of money or gifts for sex in unmarried adolescent sexual relationships in sub-Saharan Africa.

PubMed

Moore, Ann M; Biddlecom, Ann E; Zulu, Eliya M

2007-12-01

Using national survey data collected in 2004 in Burkina Faso, Ghana, Malawi, and Uganda with 12-19 year olds, we examine the prevalence of sex in exchange for money or gifts in the 12 months prior to the survey and its association with adolescents' social and economic vulnerability and condom use. Receiving something in exchange for sex is very common among sexually active, unmarried female adolescents and there are no significant differences by household economic status, orphan status, level of schooling completed or age difference between partners. Condom use at last sex in the 12 months prior to the survey is not associated with receiving gifts or money. Qualitative data based on focus group discussions and in-depth interviews collected in 2003 with adolescents suggest that receiving money or gifts for sex is not necessarily a coercive force, but rather can be a routine aspect of dating.

Crystal structures and magnetic properties of magnetite (Fe{sub 3}O{sub 4})/Polyvinyl alcohol (PVA) ribbon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ardiyanti, Harlina; Suharyadi, Edi, E-mail: esuharyadi@ugm.ac.id; Kato, Takeshi

2016-04-19

Ribbon of magnetite (Fe{sub 3}O{sub 4})/Polyvinyl Alcohol (PVA) nanoparticles have been successfully fabricated with various concentration of PVA synthesized by co-precipitation method. Particle size of nanoparticles Fe{sub 3}O{sub 4} sample and ribbon Fe{sub 3}O{sub 4}/PVA 25% sample is about 9.34 nm and 11.29 nm, respectively. The result of Vibrating Sample Magnetometer (VSM) showed that saturation magnetization value decreased from 76.99 emu/g to 15.01 emu/g and coercivity increased from 49.30 Oe to 158.35 Oe as increasing concentration of PVA. Atomic Force Microscopy (AFM) analysis showed that encapsulated PVA given decreasing agglomeration, controlled shape of nanoparticles Fe{sub 3}O{sub 4} more spherical and dispersed. Surfacemore » roughness decreased with increasing concentration of PVA.« less

High speed magneto-resistive random access memory

NASA Technical Reports Server (NTRS)

Wu, Jiin-Chuan (Inventor); Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor)

1992-01-01

A high speed read MRAM memory element is configured from a sandwich of magnetizable, ferromagnetic film surrounding a magneto-resistive film which may be ferromagnetic or not. One outer ferromagnetic film has a higher coercive force than the other and therefore remains magnetized in one sense while the other may be switched in sense by a switching magnetic field. The magneto-resistive film is therefore sensitive to the amplitude of the resultant field between the outer ferromagnetic films and may be constructed of a high resistivity, high magneto-resistive material capable of higher sensing currents. This permits higher read voltages and therefore faster read operations. Alternate embodiments with perpendicular anisotropy, and in-plane anisotropy are shown, including an embodiment which uses high permeability guides to direct the closing flux path through the magneto-resistive material. High density, high speed, radiation hard, memory matrices may be constructed from these memory elements.

Coerced First Sex among Adolescent Girls in Sub-Saharan Africa: Prevalence and Context

PubMed Central

Moore, Ann M.; Awusabo-Asare, Kofi; Madise, Nyovani; John-Langba, Johannes; Kumi-Kyereme, Akwasi

2008-01-01

Coercive experiences at sexual debut have been shown to be associated with other sexual risks throughout the life course. Using nationally representative surveys from 12–19 year old girls in Burkina Faso, Ghana, Malawi, and Uganda collected in 2004, we examine the prevalence of sexual coercion at sexual debut among unmarried girls and its correlates. In Malawi, 38 percent of girls said that they were “not willing at all” at their first sexual experience followed by Ghana at 30 percent, Uganda at 23 percent and Burkina Faso at 15 percent. In-depth interviews collected in 2003 with the same demographic shows that there are four primary types of sexual coercion: forced sex; pressure through money or gifts; flattery, pestering, and threatening to have sex with other girls; and passive acceptance. The article concludes with the research and policy implications of these findings. PMID:18458747

Structure and magnetic properties of the Nd9.5Fe84.5B6 alloy subjected to severe plastic deformation and annealing

NASA Astrophysics Data System (ADS)

Menushenkov, V. P.; Shchetinin, I. V.; Chernykh, S. V.; Savchenko, A. G.; Gorshenkov, M. V.; Zhukov, D. G.

2017-10-01

The effect of severe plastic deformation (SPD) by torsion and subsequent annealing on the structure and magnetic properties of the cast Nd9.5Fe84.5B6 alloy is studied. SPD by torsion is shown to lead to partial amorphization of the Nd2Fe14B phase and the precipitation of α-Fe; subsequent annealing results in the crystallization of the amorphous phase and the formation of a nanocomposite Nd2Fe14B/α-Fe structure. After SPD by torsion at 20 revolutions and annealing at 873 K, the (101) texture is formed; in this case, the coercive force is H c = 360 kA/m and the maximum energy product is ( BH) max = 166 kJ/m3. The residual magnetization and the squareness ratio of the hysteretic loop of the textured alloy decrease as the ambient temperature decreases.

Lodestone: Nature's own permanent magnet

NASA Technical Reports Server (NTRS)

Wasilewski, P.

1976-01-01

Magnetic hysteresis and microstructural details are presented which explain why the class of magnetic iron ores defined as proto-lodestones, can behave as permanent magnets, i.e. lodestones. Certain of these proto-lodestones which are not permanent magnets can be made into permanent magnets by charging in a field greater than 1000 oersted. This fact, other experimental observations, and field evidence from antiquity and the middle ages, which seems to indicate that lodestones are found as localized patches within massive ore bodies, suggests that lightning might be responsible for the charging of lodestones. The large remanent magnetization, high values of coercive force, and good time stability for the remanent magnetization are all characteristics of proto-lodestone iron ores which behave magnetically as fine scale ( 10 micrometer) intergrowths when subjected to magnetic hysteresis analysis. The magnetic results are easily understood by analysis of the complex proto lodestone microstructural patterns observable at the micrometer scale and less.

Synthesis of nanostructured iron oxides and new magnetic ceramics using sol-gel and SPS techniques

NASA Astrophysics Data System (ADS)

Papynov, E. K.; Shichalin, O. O.; Belov, A. A.; Portnyagin, A. S.; Mayorov, V. Yu.; Gridasova, E. A.; Golub, A. V.; Nepomnyashii, A. S.; Tananaev, I. G.; Avramenko, V. A.

2017-02-01

The original way of synthesis of nanostructured iron oxides and based on them magnetic ceramics via sequential combination of sol-gel and SPS technologies has been suggested. High quality of nanostructured iron oxides is defined by porous structure (Sspec up to 47,3 n2/g) and by phase composition of mixed and individual crystal phases (γ-Fe2O3/Fe3O4 i α-Fe2O3), depending on synthesis conditions. High-temperature SPS consolidation of nanostructured hematite powder, resulting in magnetic ceramics of high mechanical strength (fracture strength 249 MPa) has been investigated. Peculiarities of change of phase composition and composite's microstructure in the range of SPS temperatures from 700 to 900 °C have been revealed. Magnetic properties have been studied and regularities of change of magnetization (Ms) and coercive force (Hc) values of the ceramics with respect to SPS sintering temperature have been described.

Effects of heat treatment on crystallographic and magnetic properties of magnetic steels

NASA Astrophysics Data System (ADS)

Battistini, L.; Benasciutti, R.; Tassi, A.

1994-05-01

The keeper and the head of a modern electrovalve for electronic injection can be succesfully realized using AISI 430 ferromagnetic steel. Important improvements in the performance of the device, mainly in terms of its regularity and energy savings, are possible by means of a better comprehension of the origins of the steel's magnetic properties. The magnetic behaviour of the AISI 430 steel upon different heat treatments was investigated, looking for the best compromise between time saving in the heat treatments and the ensuing magnetic properties of the material. In particular, the relationships between the structural effects of the heat treatments and the magnetic behaviour of the samples were studied. Values of the coercive force Hc, residual induction Br, maximum permeability μ max and the approach to saturation values for H and B were determined by mean of a computerized permeameter, based on a Sanford-Bennet closed yoke for differently shaped samples.

Spectral ellipsometry as a method for characterization of nanosized films with ferromagnetic layers

NASA Astrophysics Data System (ADS)

Hashim, H.; Singkh, S. P.; Panina, L. V.; Pudonin, F. A.; Sherstnev, I. A.; Podgornaya, S. V.; Shpetnyi, I. A.; Beklemisheva, A. V.

2017-11-01

Nanosized films with ferromagnetic layers are widely used in nanoelectronics, sensor systems and telecommunications. Their properties may strongly differ from those of bulk materials that is on account of interfaces, intermediate layers and diffusion. In the present work, spectral ellipsometry and magnetooptical methods are adapted for characterization of the optical parameters and magnetization processes in two- and three-layer Cr/NiFe, Al/NiFe and Cr(Al)/Ge/NiFe films onto a sitall substrate for various thicknesses of Cr and Al layers. At a layer thickness below 20 nm, the complex refractive coefficients depend pronouncedly on the thickness. In two-layer films, remagnetization changes weakly over a thickness of the top layer, but the coercive force in three-layer films increases by more than twice upon remagnetization, while increasing the top layer thickness from 4 to 20 nm.

Supervisory power and its influence on staff members and their customers.

PubMed

Carson, Paula Phillips; Carson, Kerry David; Pence, Patricia Lanier

2002-01-01

The authors examined supervisors' selective use of legitimate, reward, coercive, referent, and expert powers and these power bases' influence on two outcomes: (a) employee perception of organizational support and (b) employee willingness to engage in service recovery activities with the customer. The authors found that the supervisor's use of expert, referent, and reward powers were positively related to perceived organizational support and that the use of coercive power was important in contributing to service recovery initiatives, particularly with regard to the employee's empathetic presentation to the customer.

A generalized view of self-citation: direct, co-author, collaborative, and coercive induced self-citation.

PubMed

Ioannidis, John P A

2015-01-01

The phenomenon of self-citation can present in many different forms, including direct, co-author, collaborative, and coercive induced self-citation. It can also pertain to the citation of single scientists, groups of scientists, journals, and institutions. This article presents some case studies of extreme self-citation practices. It also discusses the implications of different types of self-citation. Self-citation is not necessarily inappropriate by default. In fact, usually it is fully appropriate but often it is even necessary. Conversely, inappropriate self-citation practices may be highly misleading and may distort the scientific literature. Coercive induced self-citation is the most difficult to discover. Coercive Induced self-citation may happen directly from reviewers of articles, but also indirectly from reviewers of grants, scientific advisors who steer a research agenda, and leaders of funding agencies who may espouse spending disproportionately large funds in research domains that perpetuate their own self-legacy. Inappropriate self-citation can be only a surrogate marker of what might be much greater distortions of the scientific corpus towards conformity to specific opinions and biases. Inappropriate self-citations eventually affect also impact metrics. Different impact metrics vary in the extent to which they can be gamed through self-citation practices. Citation indices that are more gaming-proof are available and should be more widely used. We need more empirical studies to dissect the impact of different types of inappropriate self-citation and to examine the effectiveness of interventions to limit them. Copyright © 2014. Published by Elsevier Inc.

Breaking Down the Coercive Cycle: How Parent and Child Risk Factors Influence Real-Time Variability in Parental Responses to Child Misbehavior

PubMed Central

Lunkenheimer, Erika; Lichtwarck-Aschoff, Anna; Hollenstein, Tom; Kemp, Christine J.; Granic, Isabela

2016-01-01

Objective Parent-child coercive cycles have been associated with both rigidity and inconsistency in parenting behavior. To explain these mixed findings, we examined real-time variability in maternal responses to children's off-task behavior to determine whether this common trigger of the coercive cycle (responding to child misbehavior) is associated with rigidity or inconsistency in parenting. We also examined the effects of risk factors for coercion (maternal hostility, maternal depressive symptoms, child externalizing problems, and dyadic negativity) on patterns of parenting. Design Mother-child dyads (N = 96; M child age = 41 months) completed a difficult puzzle task, and observations were coded continuously for parent (e.g., directive, teaching) and child behavior (e.g., on-task, off-task). Results Multilevel continuous-time survival analyses revealed that parenting behavior is less variable when children are off-task. However, when risk factors are higher, a different profile emerges. Combined maternal and child risk is associated with markedly lower variability in parenting behavior overall (i.e., rigidity) paired with shifts towards higher variability specifically when children are off-task (i.e., inconsistency). Dyadic negativity (i.e., episodes when children are off-task and parents engage in negative behavior) are also associated with higher parenting variability. Conclusions Risk factors confer rigidity in parenting overall, but in moments when higher-risk parents must respond to child misbehavior, their parenting becomes more variable, suggesting inconsistency and ineffectiveness. This context-dependent shift in parenting behavior may help explain prior mixed findings and offer new directions for family interventions designed to reduce coercive processes. PMID:28190978

MRI induced torque and demagnetization in retention magnets for a bone conduction implant.

PubMed

Jansson, Karl-Johan Fredén; Håkansson, Bo; Reinfeldt, Sabine; Taghavi, Hamidreza; Eeg-Olofsson, Måns

2014-06-01

Performing magnetic resonance imaging (MRI) examinations in patients who use implantable medical devices involve safety risks both for the patient and the implant. Hearing implants often use two permanent magnets, one implanted and one external, for the retention of the external transmitter coil to the implanted receiver coil to achieve an optimal signal transmission. The implanted magnet is subjected to both demagnetization and torque, magnetically induced by the MRI scanner. In this paper, demagnetization and a comparison between measured and simulated induced torque is studied for the retention magnet used in a bone conduction implant (BCI) system. The torque was measured and simulated in a uniform static magnetic field of 1.5 T. The magnetic field was generated by a dipole electromagnet and permanent magnets with two different types of coercive fields were tested. Demagnetization and maximum torque for the high coercive field magnets was 7.7% ± 2.5% and 0.20 ± 0.01 Nm, respectively and 71.4% ± 19.1% and 0.18 ± 0.01 Nm for the low coercive field magnets, respectively. The simulated maximum torque was 0.34 Nm, deviating from the measured torque in terms of amplitude, mainly related to an insufficient magnet model. The BCI implant with high coercive field magnets is believed to be magnetic resonance (MR) conditional up to 1.5 T if a compression band is used around the skull to fix the implant. This is not approved and requires further investigations, and if removal of the implant is needed, the surgical operation is expected to be simple.

From the ocean to a salt marsh: towards understanding iron reduction processes with FORC-PCA.

NASA Astrophysics Data System (ADS)

Muraszko, J. R.; Lascu, I.; Collins, S. M.; Harrison, R. J.

2017-12-01

Biogenic magnetic minerals are a high fidelity recorder of climate change. Their sensitivity to sedimentary redox conditions and bottom water ventilation have the potential to provide useful insights into past diagenetic conditions. However, the mechanisms controlling preservation and dissolution of magnetosomes are not fully understood, thus undermining the reliability of the paleomagnetic records in marine environments. Recovering information about the diagenetic past of the sediment is a crucial challenge; specifically, the biogenic components need to be identified and unmixed from the bulk magnetic signal. We address the issue in this study by applying Principal Component Analysis on First Order Reversal Curve diagrams (FORC-PCA) in case studies of cores obtained from the Iberian Margin and the sedimentologically active coastal salt marshes of Norfolk. We demonstrate the applicability of FORC-PCA as a new environmental proxy, yielding a high resolution temporal marine record of environmental changes reflected in magnetic composition over the last 194 kyr. The strongest variations are observed in the microbially derived components, the bulk properties of the sediment being controlled by a low coercivity SP-SD component which is generally anticorrelated with the magnetosome signal. Supported by TEM studies, we suggest the prevalence of clusters of nano-particles of magnetite associated with iron reduction. To further investigate the mechanisms controlling these processes, the active sedimentary environment of Norfolk was chosen as a case study of early diagenesis controlled by strong vertical geochemical gradients.

Neutron diffraction and ferromagnetic resonance studies on plasma-sprayed MnZn ferrite films

NASA Astrophysics Data System (ADS)

Yan, Q. Y.; Gambino, R. J.; Sampath, S.; Huang, Q.

2005-02-01

The magnetic properties of MnZn ferrites are affected by the plasma spray process. It is found that improvements can be made by annealing the ferrite films at 500°C-800°C. The annealing induced magnetic property changes are studied by neutron diffraction and ferromagnetic resonance techniques. The increase of the saturation magnetization is attributed to the cation ordering within the spinel lattice, which increases the magnetic moment per ferrite formula. The refinements on the neutron diffraction data suggest that the redistribution of the cation during annealing neither starts from a fully disordered state nor ends to a fully ordered state. The decrease of the coercivity is analyzed with the domain wall pinning model. The measurements on the magnetostriction and residual stress indicate that coercive mechanisms arising from the magnetoelastic energy term are not dominant in these ferrite films. The decrease of the coercivity for annealed ferrite films is mainly attributed to the decrease of the effective anisotropic field, which may result from the homogenization of the film composition and the reduction of the microstructural discontinuity (e.g., cracks, voids, and splat boundaries).

Is Inspiring Group Members an Effective Predictor of Social Dominance in Early Adolescence? Direct and Moderated Effects of Behavioral Strategies, Social Skills, and Gender on Resource Control and Popularity.

PubMed

Vermande, Marjolijn M; Gilholm, Patricia A; Reijntjes, Albert H A; Hessen, Dave J; Sterck, Elisabeth H M; Overduin-de Vries, Anne M

2018-03-13

Dominance in the peer group is important for adolescents. Resource Control Theory posits that both coercive and prosocial (positively assertive) strategies are associated with dominance. Combining Resource Control Theory with Socioanalytic Theory on personality, we hypothesized that inspiring group members would be an additional effective strategy. This study examined whether the three behavioral strategies and two types of social skills (social competence and manipulation) predicted dominance (resource control and popularity). Participants were 619 Dutch adolescents (M age  = 13.1; 47% female) in the first grade of secondary school. They completed peer reports (behavioral strategies and dominance) and self-reports (social skills). Only inspirational and coercive strategies substantially predicted dominance. Main effects of social skills emerged. Moderation between strategies and social skills was only observed for girls (e.g., coercive strategy use was associated with more popularity for girls with higher levels of social manipulation skills). This study furthered our understanding of the predictors of dominance in adolescence by including inspirational behavior and examining prosocial and antisocial skills.

Epitaxial Fe{sub 3}Pt/FePt nanocomposites on MgO and SrTiO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casoli, F., E-mail: casoli@imem.cnr.it; Nasi, L.; Cabassi, R.

We have exploited the pseudomorphic growth of the magnetically soft Fe{sub 3}Pt phase on top of L1{sub 0}-FePt to obtain fully epitaxial soft/hard nanocomposites on both MgO(100) and SrTiO{sub 3}(100). The magnetic properties of this new nanocomposite system, driven by the soft/hard exchange-coupling, can be tailored by varying soft phase thickness, soft phase magnetic anisotropy and substrate. Coercivity is strongly reduced by the addition of the soft phase, a reduction which is definitely affected by the nominal composition of the soft phase and by the substrate choice; similarly is the magnetic phase diagram of the composite system. Coercive field decreasesmore » down to 21% of the hard layer value for Fe{sub 3}Pt(5 nm)/FePt(3.55 nm) nanocomposites on SrTiO{sub 3}; this maximum coercivity reduction was obtained with a nominal atomic content of Fe in the soft phase of 80%.« less

Texture development and coercivity enhancement in cast alnico 9 magnets

NASA Astrophysics Data System (ADS)

Zhang, Wenyong; Valloppilly, Shah; Li, Xingzhong; Yue, Lanping; Skomski, Ralph; Anderson, Iver; Kramer, Matthew; Tang, Wei; Shield, Jeff; Sellmyer, David J.

2018-05-01

The effect of Y addition and magnetic field on texture and magnetic properties of arc-melted alnico 9 magnets has been investigated. Small additions of Y (1.5 wt.%) develop a (200) texture for the arc-melted alnico 9 magnet. Such a texture is hard to form in cast samples. To achieve this goal, we set up a high-field annealing system with a maximum operation temperature of 1250 °C. This system enabled annealing in a field of 45 kOe with subsequent draw annealing for the solutionized buttons; we have been able to substantially increase remanence ratio and coercivity, from 0.70 and 1200 Oe for the Y-free alnico 9 to 0.90 and 1400 Oe for the Y-doped alnico 9, respectively. A high energy product of 7.3 MGOe has been achieved for the fully heat-treated Y-doped alnico 9. The enhancement of coercivity is believed to arise from the introduction of magnetocrystalline anisotropy from 80 nm Y2Co17-type grains, which are exchange-coupled to the main-phase alnico rods.

Development of flexible Ni80Fe20 magnetic nano-thin films

NASA Astrophysics Data System (ADS)

Vopson, M. M.; Naylor, J.; Saengow, T.; Rogers, E. G.; Lepadatu, S.; Fetisov, Y. K.

2017-11-01

Flexible magnetic Ni80Fe20 thin films with excellent adhesion, mechanical and magnetic properties have been fabricated using magnetron plasma deposition. We demonstrate that flexible Ni80Fe20 thin films maintain their non-flexible magnetic properties when the films are over 60 nm thick. However, when their thickness is reduced, the flexible thin films display significant increase in their magnetic coercive field compared to identical films coated on a solid Silicon substrate. For a 15 nm flexible Ni80Fe20 film coated onto 110 μm Polyvinylidene fluoride polymer substrate, we achieved a remarkable 355% increase in the magnetic coercive field relative to the same film deposited onto a Si substrate. Experimental evidence, backed by micro-magnetic modelling, indicates that the increase in the coercive fields is related to the larger roughness texture of the flexible substrates. This effect essentially transforms soft Ni80Fe20 permalloy thin films into medium/hard magnetic films allowing not only mechanical flexibility of the structure, but also fine tuning of their magnetic properties.

Composition gradient, structure, stress, roughness and magnetic properties of 5-500 nm thin NiFe films obtained by electrodeposition

NASA Astrophysics Data System (ADS)

Gong, Jie; Riemer, Steve; Kautzky, Michael; Tabakovic, Ibro

2016-01-01

The composition gradients of 5-500 nm thin NiFe films on Cu and NiP substrates obtained by electrodeposition in stirred plating solutions at pH 3.0 on 8 in wafers were studied. It was found that the average elemental composition of the NiFe changes during electrodeposition with steep downturns of Fe-content, from 58 to 50 wt% Fe, in composition gradient zone near the substrate interface in the thickness range 5-250 nm depending on the electrode substrate (Cu and NiP). The increase of Fe-content in the composition gradient zone is accompanied by the increase of coercivity, Hc, magnetic flux saturation, Bs, saturation magnetostriction, λs, increase of dimensionless roughness, ρrms, and change of stress, σ. The coercivity (easy and hard axis) follows the Neel's relation Hc=ct-n (t is thickness and c is a constant). The mechanisms related to the change of coercivity of the NiFe films deposited on different substrates (Cu and NiP) are discussed in terms of material properties of these films.

A battered women's movement perspective of Coercive Control.

PubMed

Arnold, Gretchen

2009-12-01

In Coercive Control, Evan Stark calls on battered women's activists to reorient their understanding of abusive relationships. Rather than being primarily about physical violence, he maintains, domestic violence is better conceptualized as men's attempts to destroy women's autonomy and reinstate patriarchy in intimate relationships. His analysis suggests important changes to defending battered women in court, modifications to the kinds of support services the movement provides for battered women, and changes in the laws and law enforcement regarding battering. Stark also maintains that, to end coercive control, the battered women's movement must renew its commitment not only to ensuring the safety of individual women but also to attaining the feminist goal of substantive freedom and equality for women in both public and private life. I contend that Stark's reframing of woman abuse is useful for battered women's advocates and may, in some cases but not in others, lead to more effective practices in battered women's programs. At the same time, it is likely to complicate activists' efforts to mobilize public opinion, resources, and public policy to address the problem of woman abuse.

Processing of MnBi bulk magnets with enhanced energy product

DOE PAGES

Poudyal, Narayan; Liu, Xubo; Wang, Wei; ...

2016-02-23

Here, we report magnetic properties and microstructure of high energy-product MnBi bulk magnets fabricated by low-temperature ball-milling and warm compaction technique. A maximum energy product (BH) max of 8.4 MGOe and a coercivity of 6.2 kOe were obtained in the bulk MnBi magnet at room temperature. Magnetic characterization at elevated temperatures showed an increase in coercivity to 16.2 kOe while (BH) max value decreased to 6.8 MGOe at 400 K. Microstructure characterization revealed that the bulk magnets consist of oriented uniform nanoscale grains with average size about 50 nm.

Rape Myths, Rape Scripts, and Common Rape Experiences of College Women: Differences in Perceptions of Women Who Have Been Raped.

PubMed

Hockett, Jericho M; Saucier, Donald A; Badke, Caitlyn

2016-03-01

Rape is prevalent at colleges. Although research suggests commonalities across many college women's rape experiences (e.g., perpetrators using multiple coercive strategies), vignettes used to assess rape perceptions often reflect false beliefs. Two studies varying a perpetrator's coercive tactics examine rape perceptions using vignettes reflecting rape myths, rape scripts, or many college women's common rape experiences. Participants perceive a woman who was raped more positively in vignettes reflecting common rape experiences versus those reflecting rape myths or scripts. Theoretical, educational, and research implications are discussed. © The Author(s) 2015.

Magnetic Properties of NdFe10Mo2-N Bonded Magnet

NASA Astrophysics Data System (ADS)

Zhang, Hong-Wei; Hu, Bo-Ping; Han, Zhong-Fan; Jin, Han-Min; Fu, Quan

1997-06-01

The dependence of remanence and coercivity on the magnetizing field is studied for isotropic and anisotropic epoxy resin bonded magnets. It was found that the coercivity of the NdFe10Mo2-N bonded magnet is mainly controlled by nucleation of reversed magnetic domains. Variation of iHc with Zn content and heat treatment conditions is studied. The value of 0 iHc obtained in the best Zn-bonded condition is about 0.15 T higher than before bonding. The variation of the amount of α-Fe with processing conditions is demonstrated for anisotropic Zn-bonded magnets.

Mental health nurses' emotions, exposure to patient aggression, attitudes to and use of coercive measures: Cross sectional questionnaire survey.

PubMed

Jalil, Rahul; Huber, Jorg W; Sixsmith, Judith; Dickens, Geoffrey L

2017-10-01

Mental health nurses are exposed to patient aggression, and required to manage and de-escalate aggressive incidents; coercive measures such as restraint and seclusion should only be used as a last resort. An improved understanding of links between nurses' exposure to aggression, attitudes to, and actual involvement in, coercive measures, and their emotions (anger, guilt, fear, fatigue, sadness), could inform preparation and education for prevention and management of violence. To identify relationships between mental health nurses' exposure to patient aggression, their emotions, their attitudes towards coercive containment measures, and their involvement in incidents involving seclusion and restraint. Cross-sectional, correlational, observational study. Low and medium secure wards for men and women with mental disorder in three secure mental health hospitals in England. N=Sixty eight mental health nurses who were designated keyworkers for patients enrolled into a related study. Participants completed a questionnaire battery comprising measures of their exposure to various types of aggression, their attitudes towards seclusion and restraint, and their emotions. Information about their involvement in restraint and/or restraint plus seclusion incidents was gathered for the three-month period pre- and post- their participation. Linear and logistic regression analyses were performed to test study hypotheses. Nurses who reported greater exposure to a related set of aggressive behaviours, mostly verbal in nature, which seemed personally derogatory, targeted, or humiliating, also reported higher levels of anger-related provocation. Exposure to mild and severe physical aggression was unrelated to nurses' emotions. Nurses' reported anger was significantly positively correlated with their endorsement of restraint as a management technique, but not with their actual involvement in restraint episodes. Significant differences in scores related to anger and fatigue, and to fatigue and guilt, between those involved/not involved in physical restraint and in physical restraint plus seclusion respectively were detected. In regression analyses, models comprising significant variables, but not the variables themselves, predicted involvement/non-involvement in coercive measures. Verbal aggression which appears targeted, demeaning or humiliating is associated with higher experienced anger provocation. Nurses may benefit from interventions which aim to improve their skills and coping strategies for dealing with this specific aggressive behaviour. Nurse-reported anger predicted approval of coercive violence management interventions; this may have implications for staff deployment and support. However, anger did not predict actual involvement in such incidents. Possible explanations are that nurses experiencing anger are sufficiently self-aware to avoid involvement or that teams are successful in supporting colleagues who they perceive to be 'at risk'. Future research priorities are considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetic anisotropy at material interfaces

NASA Astrophysics Data System (ADS)

Greene, Peter Kevin

In this dissertation, a comprehensive set of depth dependent magnetic measurements, as well as structural characterizations, were carried out on the Co/Pd multilayer system. The first-order reversal curve (FORC) technique is applied extensively to identify reversal mechanisms and different reversal phases within the material. In particular, the extension of the FORC technique to x-ray magnetic circular dichroism (XMCD) as a surface sensitive technique that identifies reversible magnetization change was performed for the first time. Polarized neutron reflectivity (PNR) was also used to directly measure the magnetization as a function of depth. The effects of deposition pressure grading within the Co/Pd multilayers were investigated. Structures were graded with three distinct pressure regions. FORC analysis shows that not only does increasing the deposition pressure increase the coercivity and effective anisotropy within that region, but also the order in which the pressure is changed also affects the entire structure. Layers grown at high sputtering pressures tend to reverse via domain wall pinning and rotation while those grown at lower pressures reverse via rapid domain wall propagation laterally across the film. Having high pressure layers underneath low pressure layers causes disorder to vertically propagate and lessen the induced anisotropy gradient. This analysis is confirmed by depth dependent magnetization profiles obtain from PNR. Continuously pressure-graded Co/Pd multilayers were then sputtered at two incident angles onto porous aluminum oxide templates with different pore aspect ratios. The effects of pressure grading versus uniform low pressure deposition is studied, as well as the effect of the angle of the incident deposition flux. The coercivity of the pressure graded perpendicular flux sample is compared to the low pressure sample. Additionally the effect of deposition angle and pore sidewall deposition is investigated. It is shown that sidewall deposition strongly affects the reversal behavior. As another way to induce a vertical anisotropy gradient, Co/Pd multilayers were bombarded with Ar+ ions at different energies and fluences. The effects of the depth dependent structural damage as a function of irradiation conditions were investigated. It is shown that the structural damage weakens the perpendicular anisotropy of the surface layers, causing a tilting of the surface magnetic moment into the plane of the film. The surface behavior is explicitly measured and shown to have a significant tilting angle in the top 5 nm depending on irradiation energy and fluence. Continuing the study of vertical anisotropy gradients in Co/Pd multilayers, multilayers with varied Co thickness were studied. Four films with varying Co thickness profiles were created and then patterned into nanodot arrays with diameters between 700 nm and 70 nm. The different films were graded continuously, or in stacks with varying Co thicknesses. An anisotropy gradient is shown to be established in the graded samples, and the switching field is lowered as a result. Furthermore, in the continuously graded samples the magnetization reversal behavior is fundamentally different from all other samples. The thermal energy barriers are measured in the uniform and continuously graded samples, yielding similar results. Finally, the establishment of exchange anisotropy at the ferromagnet / antiferromagnet (FM/AFM) interface in the epitaxial Fe/CoO system is investigated as a function of AFM thickness. The establishment of frozen AFM moments is analyzed using the FORC technique. The FORC technique combined with vector coil measurements also shows the transition from rotatable AFM to pinned AFM moments and suggests a mechanism of winding domain walls within the bulk AFM. (Abstract shortened by UMI.).

Prospective Predictors of Technology-Based Sexual Coercion by College Males

PubMed Central

Thompson, Martie P.; Morrison, Deidra J.

2013-01-01

Objective Technology-based coercive behavior (TBC) represents an emerging public health problem. This study contributes to the literature by identifying prospective individual-, social-, and community-level predictors of TBC. Method Data were collected from 800 males who participated in a prospective study on attitudes and behaviors regarding relationships with women. Variables across multiple ecological layers were used to predict TBC. Results Bivariate analyses indicated that 16 of the 17 risk variables significantly predicted TBC including anger, impulsivity, sexual compulsivity, hostility towards women, rape supportive beliefs, high-risk drinking, childhood sexual abuse, interparental conflict, peer pressure to engage in sex, peer approval of forced sex, number of sexual partners, perceived negative sanctions for sexual aggression, exposure to pornography, and participation in varsity sports, student government, and religious groups. Multivariate regression analyses indicated five variables uniquely accounted for TBC behaviors, including rape supportive beliefs, peer approval of forced sex, number of sexual partners, exposure to pornography, and participation in student government. Conclusions Our findings that TBC can be prospectively predicted by these risk factors suggest that computer-based technology interventions focusing on these factors through social network ads that promote reflection on healthy social and romantic relationship behaviors and attitudes could help prevent and reduce TBC. PMID:24073356

New magnetic rails with double-layer Halbach structure by employing NdFeB and ferrite magnets for HTS maglev

NASA Astrophysics Data System (ADS)

Sun, Ruixue; Zheng, Jun; Zheng, Botian; Qian, Nan; Li, Jipeng; Deng, Zigang

2018-01-01

In the high temperature superconducting (HTS) maglev system, the magnetic rail as an essential infrastructure is needed all along the route to carry passengers and goods to the destinations. Thus, large amount of rare earth magnetic materials are required in the magnetic rail construction. In order to decrease the dependence of magnetic rails on rare earth elements, the ferrite magnet is employed to replace part of the NdFeB magnets containing rare earth elements. Consequently, a new type rail with double-layer Halbach structure is presented, which is consisted of NdFeB and ferrite magnets. In this paper, we designed and fabricated the proposed rail, and further measured its magnetic flux density distribution and electromagnetic force interacting with HTS bulks. Experimental results indicate that, this new type rail, in double-layer Halbach structure, can achieve an equivalent distribution of magnetic flux density and levitation performance as the pure NdFeB Halbach rail, while a 10% reduction in NdFeB magnet consumption can be realized at the same time. In addition this work explores another magnetic material selection for HTS maglev applications. The dependence on rare earth element and the cost of magnetic rails can be further reduced, as the coercive force of ferrite magnets improved.

Iron Oxide Nanoparticles: Tunable Size Synthesis and Analysis in Terms of the Core-Shell Structure and Mixed Coercive Model

NASA Astrophysics Data System (ADS)

Phong, P. T.; Oanh, V. T. K.; Lam, T. D.; Phuc, N. X.; Tung, L. D.; Thanh, Nguyen T. K.; Manh, D. H.

2017-04-01

Iron oxide nanoparticles (NPs) are currently a very active research field. To date, a comprehensive study of iron oxide NPs is still lacking not only on the size dependence of structural phases but also in the use of an appropriate model. Herein, we report on a systematic study of the structural and magnetic properties of iron oxide NPs prepared by a co-precipitation method followed by hydrothermal treatment. X-ray diffraction and transmission electron microscopy reveal that the NPs have an inverse spinel structure of iron oxide phase (Fe3O4) with average crystallite sizes ( D XRD) of 6-19 nm, while grain sizes ( D TEM) are of 7-23 nm. In addition, the larger the particle size, the closer the experimental lattice constant value is to that of the magnetite structure. Magnetic field-dependent magnetization data and analysis show that the effective anisotropy constants of the Fe3O4 NPs are about five times larger than that of their bulk counterpart. Particle size ( D) dependence of the magnetization and the non-saturating behavior observed in applied fields up to 50 kOe are discussed using the core-shell structure model. We find that with decreasing D, while the calculated thickness of the shell of disordered spins ( t ˜ 0.3 nm) remains almost unchanged, the specific surface areas S a increases significantly, thus reducing the magnetization of the NPs. We also probe the coercivity of the NPs by using the mixed coercive Kneller and Luborsky model. The calculated results indicate that the coercivity rises monotonously with the particle size, and are well matched with the experimental ones.

Predicting family health and well-being after separation from an abusive partner: role of coercive control, mother's depression and social support.

PubMed

Broughton, Sharon; Ford-Gilboe, Marilyn

2017-08-01

Drawing on the Strengthening Capacity to Limit Intrusion theory, we tested whether intrusion (i.e. unwanted interference from coercive control, custody and access difficulties and mother's depressive symptoms) predicted family health and well-being after separation from an abusive partner/father, and whether social support moderated intrusion effects on family health and well-being. Experiences of coercive control and the negative consequences related to those experiences have been documented among women who have separated from an abusive partner. We conducted a secondary analysis of data from 154 adult, Canadian mothers of dependent children who had separated from an abusive partner and who participated in Wave 2 of the Women's Health Effects Study. We used hierarchical multiple regression to test whether intrusion predicts family health and well-being as well as whether social support moderated this relationship. Families were found to experience considerable intrusion, yet their health and well-being was similar to population norms. Intrusion predicted 11·4% of the variance in family health and well-being, with mother's depressive symptoms as the only unique predictor. Social support accounted for an additional 9% of explained variance, but did not buffer intrusion effects on family health and well-being. Although women had been separated from their abusive partners for an average of 2·5 years, the majority continued to experience coercive control. On average, levels of social support and family functioning were relatively high, contrary to public and academic discourse. In working with these families postseparation, nurses should approach care from a strength-based perspective, and integrate tailored assessment and intervention options for women and families that address both depression and social support. © 2016 John Wiley & Sons Ltd.

"If I Can't Have You Nobody Will": Explicit Threats in the Context of Coercive Control.

PubMed

Logan, T K

2017-02-01

Physical assault is only one tool in partner abuse characterized by coercive control. Coercive control creates an ongoing state of fear and chronic stress. Explicit threats are an important component of coercive control yet have received limited research attention. This study examined 210 women with protective orders (POs) against abusive (ex)partners and their experiences of explicit threats including threats of harm and death, threats about harming friends and family, and actual threats to friends and family. There are 4 main findings from this study: (a) explicit threats of harm and death, threats about harming others, and actual threats to others are common both in the history of the abusive relationship as well as within 6 months prior to obtaining a PO but are only moderately correlated with each other; (b) the high-frequency threats of harm group had the highest rates of concurrent abuse, violence, distress, and fear; (c) the prevalence and frequency of threats changed over time for all 3 types of threats examined in this study; and (d) understanding the variety of threats partner abuse victims experience, especially threats of third-party harm, may be important in understanding the larger context and consequences of partner abuse. This study is an interim step toward a better understanding of the role of explicit threats in abusive relationships. Future research is needed to examine the prevalence, frequency, trajectory, features, context, and types of explicit threats that victims of partner abuse experience. This information may be especially key to understanding more about future risk of harm, risk of harm to others, victim distress and fear, and safety planning.

Does the Sole Description of a Tax Authority Affect Tax Evasion? - The Impact of Described Coercive and Legitimate Power

PubMed Central

Hartl, Barbara; Hofmann, Eva; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

2015-01-01

Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority’s power. Descriptions of the tax authority’s power may affect taxpayers’ beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority’s power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority’s power on participants’ beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants’ beliefs regarding tax authority’s power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority’s power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information. PMID:25923770

Does the sole description of a tax authority affect tax evasion?--the impact of described coercive and legitimate power.

PubMed

Hartl, Barbara; Hofmann, Eva; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

2015-01-01

Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority's power. Descriptions of the tax authority's power may affect taxpayers' beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority's power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority's power on participants' beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants' beliefs regarding tax authority's power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority's power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information.

A Comparison of Intimate Partner Violence Strangulation Between Same-Sex and Different-Sex Couples.

PubMed

Messing, Jill T; Thomas, Kristie A; Ward-Lasher, Allison L; Brewer, Nathan Q

2018-03-01

Strangulation is a common and dangerous form of intimate partner violence (IPV). Nonfatal strangulation is a risk factor for homicide; can lead to severe, long-term physical and mental health sequelae; and can be an effective strategy of coercion and control. To date, research has not examined strangulation within same-sex couples. The objective of this cross-sectional, observational research is to identify whether and to what extent the detection of strangulation and coercive control differs between same-sex and different-sex couples in police reports of IPV. Data ( n = 2,207) were obtained from a single police department in the southwest United States (2011-2013). Bivariate analyses examined differences in victim and offender demographics, victim injury, violence, and coercive controlling behaviors between same-sex (male-male and female-female) and different-sex couples (female victim-male offender). Logistic regression was used to examine associations between strangulation, victim and offender demographics, coercive controlling behaviors, and couple configuration. Strangulation was reported significantly more often in different-sex (9.8%) than in female and male same-sex couple cases (5.2% and 5.3%, respectively; p < .05). Injury, however, was reported more frequently in same-sex than in different-sex couples ( p < .05). Couple configuration ( p < .05), coercive control ( p < .05), and injury ( p < .05) significantly predict strangulation. Findings suggest that nonfatal strangulation occurs within at least a minority of same-sex couples; it is possible that underdetection by law enforcement makes it appear less common than it actually is. Regardless of couple configuration, timely identification of strangulation and subsequent referral to medical and social service providers is essential for preventing repeated strangulation, life-threatening injury, and the long-term health effects of strangulation.

Human uniqueness-self-interest and social cooperation.

PubMed

Okada, Daijiro; Bingham, Paul M

2008-07-21

Humans are unique among all species of terrestrial history in both ecological dominance and individual properties. Many, or perhaps all, of the unique elements of this nonpareil status can be plausibly interpreted as evolutionary and strategic elements and consequences of the unprecedented intensity and scale of our social cooperation. Convincing explanation of this unique human social adaptation remains a central, unmet challenge to the scientific enterprise. We develop a hypothesis for the ancestral origin of expanded cooperative social behavior. Specifically, we present a game theoretic analysis demonstrating that a specific pattern of expanded social cooperation between conspecific individuals with conflicts of interest (including non-kin) can be strategically viable, but only in animals that possess a highly unusual capacity for conspecific violence (credible threat) having very specific properties that dramatically reduce the costs of coercive violence. The resulting reduced costs allow preemptive or compensated coercion to be an instantaneously self-interested behavior under diverse circumstances rather than in rare, idiosyncratic circumstances as in actors (animals) who do not have access to inexpensive coercive threat. Humans are apparently unique among terrestrial organisms in having evolved conspecific coercive capabilities that fulfill these stringent requirements. Thus, our results support the proposal that access to a novel capacity for projection of coercive threat might represent the essential initiating event for the evolution of a human-like pattern of social cooperation and the subsequent evolution of the diverse features of human uniqueness. Empirical evidence indicates that these constraints were, in fact, met only in our evolutionary lineage. The logic for the emergence of uniquely human cooperation suggested by our analysis apparently accounts simply for the human fossil record.

Effect of ball milling and heat treatment process on MnBi powders magnetic properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Wei; Polikarpov, Evgueni; Choi, Jung-Pyung

The metallic compound MnBi has high intrinsic coercivity with large positive temperature coefficient. The coercivity of MnBi exceeds 12 kOe and 26 kOe at 300 K and 523 K, respectively. Hence MnBi is a good candidate for the hard phase in exchange coupled nanocomposite magnets. In order to maximize the loading of the soft phase, the size of the MnBi particle has to be close to 500 nm, the size of single magnetic domain. Low energy milling is the common method to reduce MnBi particle size. However, only 3-7 mu m size particle can be achieved without significant decomposition. Here,more » we report our effort on preparing submicron MnBi powders using traditional powder metallurgy methods. Mn55Bi45 magnetic powders were prepared using arc melting method, followed by a series of thermal-mechanical treatment to improve purity, and finished with low energy ball milling at cryogenic temperature to achieve submicron particle size. The Mn55Bi45 powders were decomposed during ball milling process and recovered during 24 h 290 degrees C annealing process. With increasing ball-milling time, the saturation magnetization of MnBi decreases, while the coercivity increases. Annealing after ball milling recovers some of the magnetization, indicating the decomposition occurred during the ball-milling process can be reversed. The coercivity of Mn55Bi45 powders are also improved as a result of the heat treatment at 290 degrees C for 24 h. The world record magnetization 71.2 emu/g measured applying a field of 23 kOe has been achieved via low energy ball mill at room temperature« less

[German practice of involuntary commitment at both federal and state level after introduction of the Guardianship law (1992-2009)].

PubMed

Valdes-Stauber, J; Deinert, H; Kilian, R

2012-05-01

Given the steady rise of psychiatric coercive measures in Germany, the question arises whether this development is significantly influenced by the corresponding legal basis or through epidemiological, socio-economic or socio-structural factors. Based on full surveys of the Federal Ministry of Justice we examined the development and associations of 10 indicators of coercive psychiatric measures over a period of 18 years. Time trends of all indicators have been descriptively analysed. Statistical associations between time trends and between involuntary and admissions economic indicators were analysed by regression models. All annual involuntary commitment rates have increased, judicial ordered physical restraint measures particularly strongly (848%). The rate of judicial rejections of applied involuntary measures showed the lowest increase. On the other hand, quotas of involuntary admissions remained stable. In former East Germany, the involuntary admission rates are only a third of those in the former West Germany. Results of regression analyses indicate an excess increase of physical coercive measures in psychiatric hospitals in relation to the increase of psychiatric admissions. In former East Germany the rate of involuntary admissions at the federal state level is negatively correlated with the average gross income. The continuous increase of coercive psychiatric measures in consequence to the change in the Guardianship law suggests that this change has influenced the practice. The differences at federal and state levels, and the sharper rise in the former East Germany by lower rates in comparison to the former West Germany need an explanation, as well as the fact that the rate of involuntary admissions is associated at least in the former East Germany with economic conditions. © Georg Thieme Verlag KG Stuttgart · New York.

Giant coercivity in perpendicularly magnetized cobalt monolayer

NASA Astrophysics Data System (ADS)

Lin, D. C.; Song, C.; Cui, B.; Wang, Y. Y.; Wang, G. Y.; Pan, F.

2012-09-01

We report giant coercivity (HC) up to 35 kOe at 4 K, measured by the anomalous Hall effect, in perpendicularly magnetized Co (˜0.3 nm) films, where Co is approximately one monolayer. The HC is dramatically reduced with huge applied current, due to Joule heating rather than Rashba effect. It is also sensitive to temperatures, producing almost zero HC at 200 K. The Curie temperature of the Co monolayer is ˜275 K, far lower than that of bulk Co. The giant HC could be explained by the strong interaction at Co/Pd interface, providing a promising paradise: one monolayer, one permanent magnet.

Control of magnetization reversal in oriented strontium ferrite thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Debangsu, E-mail: debangsu@physics.iisc.ernet.in; Anil Kumar, P. S.

2014-02-21

Oriented Strontium Ferrite films with the c axis orientation were deposited with varying oxygen partial pressure on Al{sub 2}O{sub 3}(0001) substrate using Pulsed Laser Deposition technique. The angle dependent magnetic hysteresis, remanent coercivity, and temperature dependent coercivity had been employed to understand the magnetization reversal of these films. It was found that the Strontium Ferrite thin film grown at lower (higher) oxygen partial pressure shows Stoner-Wohlfarth type (Kondorsky like) reversal. The relative importance of pinning and nucleation processes during magnetization reversal is used to explain the type of the magnetization reversal with different oxygen partial pressure during growth.

Coercive control and abused women's decisions about their pets when seeking shelter.

PubMed

Hardesty, Jennifer L; Khaw, Lyndal; Ridgway, Marcella D; Weber, Cheryl; Miles, Teresa

2013-09-01

The importance of pets in families, especially during major life stressors, is well documented. Research suggests links between pet ownership and intimate partner violence (IPV). This study explored abused women's decisions about pets when seeking help from a shelter. Interviews were conducted with 19 women who were pet owners. Using grounded theory methods, two patterns emerged surrounding abusers' treatment of pets, bonds to pets, women's decisions about pets upon seeking shelter, and future plans for pets. The presence of coercive control was central to these patterns. Women also discussed their experiences with and needs from shelter professionals and veterinarians with implications for practice.

Hydrogen Decrepitation Press-Less Process recycling of NdFeB sintered magnets

NASA Astrophysics Data System (ADS)

Xia, Manlong; Abrahamsen, Asger B.; Bahl, Christian R. H.; Veluri, Badrinath; Søegaard, Allan I.; Bøjsøe, Poul

2017-11-01

A Hydrogen Decrepitation Press-Less Process (HD-PLP) recycling method for recycling of anisotropic NdFeB magnets is demonstrated. The method combines hydrogen decrepitation (HD) disintegration of the initial magnet, powder sieving and the Press-Less Process (PLP), where hydride powder is sintered in a graphite mold. Coercivities up to 534 kA/m were obtained in porous samples based on powder size d < 100 μm. Adding a ball milling step resulted in full density isotropic magnets for d > 100 μm. The coercivity reached Hci = 957 kA/m being 86% of the original N48M material without addition of rare earth elements.

Plasma sprayed Fe(76)Nd(16)B(8) permanent magnets

NASA Technical Reports Server (NTRS)

Overfelt, R. A.; Anderson, C. D.; Flanagan, W. F.

1986-01-01

Thin coatings (0.16 mm) and thick coatings (0.50 mm) of Fe(76)Nd(16)B(8) were deposited on stainless-steel substrates by low pressure plasma spraying. Microscopic examination of the coatings in a light microscope revealed excessive porosity, but good bonding to the substrate. Fracture cross sections examined in a scanning electron microscope showed the grains to be equiaxed and approximately 1 micron or less in diameter in the as-sprayed condition. The intrinsic coercivities of the as-sprayed coatings varied from 5.8 to 10.9 kOe. The effects of postspray heat treatments on the intrinsic coercivity are also given.

Measuring coercive control: what can we learn from national population surveys?

PubMed

Myhill, Andy

2015-03-01

Numerous academic studies point to gender symmetry in the prevalence of intimate partner violence (IPV). Many of these studies report findings from surveys with small and/or unrepresentative samples that have insufficient questions to differentiate adequately between different types of abuse. Data from a large, nationally representative survey suggest that, while the prevalence of situational violence is fairly symmetrical, coercive controlling abuse is highly gendered, with women overwhelmingly the victims. The authors conclude that more comprehensive measures are required in national surveys that consider a wider range of controlling behaviors as well as the meaning and impact of abuse. © The Author(s) 2015.

Rapid sintering of anisotropic, nanograined Nd-Fe-B by flash-spark plasma sintering

NASA Astrophysics Data System (ADS)

Castle, Elinor; Sheridan, Richard; Grasso, Salvatore; Walton, Allan; Reece, Mike

2016-11-01

A Spark Plasma Sintering (SPS) furnace was used to Flash-Sinter (FS) Nd-Fe-Dy-Co-B-Ga melt spun permanent magnetic material. During the 10 s "Flash" process (heating rate 2660 K min-1), sample sintering (to theoretical density) and deformation (54% height reduction) occurred. This produced texturing and significant magnetic anisotropy, comparable to conventional die-upset magnets; yet with much greater coercivities (>1600 kA m-1) due to the nanoscale characteristics of the plate-like sintered grains. These preliminary results suggest that Flash-SPS could provide a new processing route for the mass production of highly anisotropic, nanocrystalline magnetic materials with high coercivity.

Manipulating mentors' assessment decisions: Do underperforming student nurses use coercive strategies to influence mentors' practical assessment decisions?

PubMed

Hunt, Louise A; McGee, Paula; Gutteridge, Robin; Hughes, Malcolm

2016-09-01

There is growing evidence of a culture of expectation among nursing students in Universities which leads to narcissistic behaviour. Evidence is growing that some student nurses are disrespectful and rude towards their university lecturers. There has been little investigation into whether they exhibit similar behaviour towards their mentors during practical placements, particularly when they, the students, are not meeting the required standards for practice. This paper focuses on adding to the evidence around a unique finding - that student nurses can use coercive and manipulative behaviour to elicit a successful outcome to their practice learning assessment (as noted in Hunt et al. (2016, p 82)). Four types of coercive student behaviour were identified and classified as: ingratiators, diverters, disparagers and aggressors, each of which engendered varying degrees of fear and guilt in mentors. The effects of each type of behaviour are discussed and considered in the light of psychological contracts. Mechanisms to maintain effective working relationships between student nurses and mentors and bolster the robustness of the practical assessment process under such circumstances are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Magnetic properties of NdFeB-coated rubberwood composites

NASA Astrophysics Data System (ADS)

Noodam, Jureeporn; Sirisathitkul, Chitnarong; Matan, Nirundorn; Rattanasakulthong, Watcharee; Jantaratana, Pongsakorn

2013-01-01

Magnetic properties of composites prepared by coating lacquer containing neodymium iron boron (Nd-Fe-B) powders on rubberwood were characterized by vibrating sample magnetometry (VSM), magnetic moment measurements, and attraction tests with an iron-core solenoid. The Nd-Fe-B powders were recycled from electronic wastes by the ball-milling technique. Varying the milling time from 20 to 300 min, the magnetic squareness and the coercive field of the Nd-Fe-B powders were at the minimum when the powders were milled for 130 min. It followed that the coercive field of the magnetic wood composites was increased with the milling time increasing from 130 to 300 min. For the magnetic wood composites using Nd-Fe-B obtained from the same milling time, the magnetic squareness and the coercive field were rather insensitive to the variation of Nd-Fe-B concentration in coating lacquer from 0.43 to 1.00 g/cm3. By contrast, the magnetization and magnetic moment were increased with the Nd-Fe-B concentration increasing. Furthermore, the electrical current in the solenoid required for the attraction of the magnetic wood composites was exponentially reduced with the increase in the amount of Nd-Fe-B used in the coating.

Synthesis and optimization of the magnetic properties of aligned strontium ferrite nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebrahimi, Fatemeh, E-mail: F.Ebrahimi@ma.iut.ac.ir; Bakhshi, Saeed Reza; Ashrafizadeh, Fakhreddin

Highlights: • Dip coating method was used to synthesize strontium ferrite nanowires in template. • Size of nanowires was controlled via anodization parameters. • Fe/Sr ratio was optimized in precursor. • Magnetic properties of nanowires and nanopowders were compared. - Abstract: High aspect ratio strontium hexaferrite nanowires were fabricated by dip coating in alumina template. Fe/Sr ratio was changed from 10 to 12 in precursor, and the samples were annealed at a range of temperatures 500–900 °C in order to optimize the magnetic properties of strontium ferrite in the form of nanowires. Field emission scanning electron microscope (FESEM) proved themore » formation of nanowires in the templates, while TEM images revealed a high degree of crystallinity. The ferrites were further characterized by X-ray diffraction (XRD) and energy dispersive X-ray spectrometer (EDS). Magnetic properties of the specimens were studied by a SQUID at 10–300 K. The results showed that the coercivity of packed density nanowires in the template was much less than that of the nanopowders. On the other hand, the coercivity of nanowires at ambient temperature was less than low temperature coercivity.« less

Magnetic Properties and Microstructure of Some 2:17 High Temperature Magnets

NASA Astrophysics Data System (ADS)

Meng-Burany, X.; Hadjipanayis, George C.; Chui, S. T.

1997-03-01

Recent DOD demands for electric vehicle/plane applications require the use of magnets with operating temperatures > 450^circ C . Of existing high performance magnets, only the Sm(Co,Fe,Cu,Zr)z precipitation--hardened magnets have an operating temperature (300^circ C) which is close to the desired temperature and this makes these magnets potential candidates for further optimization studies. We have started a systematic study and modeling of the high temperature magnetic properties of several commercial magnets and other specially designed magnets supplied to us by Crucible Research. All the samples studied had a room temperature coercivity above 15 kOe. The coercivity was found to decrease with increasing temperature, with values of less than 4 kOe at 450^circ C , except for one sample which had a better temperature dependence with a coercivity above 6 kOe. TEM studies showed a cellular microstructure in all samples. The sample with better temperature properties had a smaller cell size but thicker cell walls. Lorentz electron microscopy studies are underway to image the domain walls and study their interaction with the cellular structure. The results of these studies will hopefully help us to understand the composition--microstructure--property relation in these magnets.

The influence of parenting style on health related behavior of children: findings from the ChiBS study.

PubMed

Philips, Nele; Sioen, Isabelle; Michels, Nathalie; Sleddens, Ester; De Henauw, Stefaan

2014-07-23

Exploring associations between parenting behavior and children's health related behavior including physical activity, sedentary behavior, diet and sleep. We recruited 288 parents and their children (6-12y old). Children's weight and height were measured. Fat percentage was determined by air displacement plethysmography. Parents reported socio-demographic data, sleep information, physical activity and sedentary behavior of their child and completed the Comprehensive General Parenting Questionnaire (CGPQ) and a Food Frequency Questionnaire. Children completed the Dutch Eating Behavior Questionnaire. Associations between parenting behavior (CGPQ) and children's health related behavior were assessed with univariate and multiple regression analyses. A small positive correlation was found between sweet food consumption frequency and "coercive control" (r = 0.139) and a small negative correlation between fruit and vegetables consumption frequency and "overprotection" (r = -0.151). Children consumed more frequently soft drinks when their parents scored lower on "structure" (r = -0.124) and higher on "overprotection" (r = 0.123); for the light soft drinks separately, a small positive correlation with "behavioral control" was found (r = 0.172). A small negative correlation was found between "emotional eating" and "structure" (r = -0.172) as well as "behavioral control" (r = -0.166). "Coercive control" was negatively correlated with the child's sleep duration (r = -0.171). After correction for confounding factors, the following significant associations were found: (1) a small negative association between "structure" and soft drinks consumption (β = -0.17 for all soft drinks and -0.22 for light soft drinks), (2) a small positive association between "behavioral control" and light soft drinks (β = 0.34), (3) a small positive association of "nurturance" and "coercive control" with sedentary behavior (β = 0.16 for both parent constructs) and (4) a small negative association between the parenting construct "coercive control" and sleep duration (β = -0.23). The significant but small associations between parenting constructs and the investigated variables suggest that different aspects of parenting style play an important role in the genesis of the health related behavior of children. Overall, our findings suggest that health professionals should encourage parents to apply the more positive parenting constructs i.e., more "structure" and "behavioral control", and less "coercive control". They could, for instance, supervise and manage their child's activities and help their child to achieve certain goals.

Isotropic rare earth based hard magnets through non-equilibrium processing

NASA Astrophysics Data System (ADS)

Sultana, Dilara

The aim of this thesis was to understand better the relationship of hard magnetic properties to the microstructure and use this knowledge to design a better magnet. The first project was focused on the development of isotropic Pr 9Fe85B6 ribbons with enhanced remanence, high coercivity and high (BH)max. The optimization was achieved by adjusting the composition, controlling the microstructure and processing parameters. The crystal structure in all the samples studied was found to consist of a fine mixture of hard phase 2:14:1 and soft alpha-Fe phase. In all the samples the optimum (BH)max obtained was in the optimally quenched ribbons. Annealing did improve the magnetic properties but did not exceed the highest (BH)max value obtained in the optimally quenched ribbons. Small additions of Tb and Co were found to improve the magnetic properties. The properties were optimized by first adjusting the wheel speed and then the ejection temperature of melt. A maximum (BH)max 21 MGOe and a remanence of 117 emu/g were obtained in the ribbons spun at 18 m/s and ejected at a temperature of 1360°C with a average grain size of 20 nm. This investigation suggests that a proper combination of composition and processing parameters is essential for the optimum (BH)max value for the Pr-Fe-B magnets. The second project was focused on the development of a single phase nanocrystalline Sm2(Co, Fe)17 magnets. The magnetic properties such as coercivity and energy product were optimized via the design of composition, control of melt-spinning parameters and heat treatment. The effect of non magnetic elements like Si, B, addition on the Sm(Co, Fe, M)z alloys were investigated. The effect of C addition on the Smx(Co 1-yMy)100-x-zCz series alloys where, M= Fe or Fe+Mn , X=10-15, Y= 0-0.375, Z= 0-6 were studied thoroughly. It is observed that the crystal structure of Sm(Co0.75Fe0.25) 7, Sm(Co0.65Fe0.25Si0.1)7 and Sm(Co0.65Fe0.25Si0.05B0.05 )8 alloy ribbons spun at low wheel speed shows the presence of 1:5 and 2:17 phase and the metastable 1:7 phase for high wheel speed. It is observed that C suppressed the formation of the stable 2:17 structure in favor of the disordered 1:7 phase. Addition of Si and B, C leads to the development of equiaxed finer grains. C may have act as grain growth inhibitor in the Sm-(Co-Fe)- C ribbons Microstructure refinement with the precipitation of RCoC2 carbides was observed in the C added ribbons. The carbon addition enhances the overall magnetic properties. The 3rd project was focused on the investigation of giant intrinsic magnetic hardness in Sm(Co0.45,Fe0.15,Cu0.4) 5 alloys and determine its dependence on grain / particle size. Melt-spinning and high energy ball milling was used to prepare sample with different grain size (6-500 nm). A single phase 1:5 structure was observed in both the ribbons and milled powders of the Sm(Co0.45,Fe0.15,Cu0.4 )5 alloy. The maximum coercivity obtained was 21 kOe for ribbons spun at 50 m/s (70 nm) and 15 kOe for the powders milled for 15 min (15 nm). Low temperature annealing of ribbons with large grain size > 500 nm for 133 h increases the coercivity to 44 kOe similar like bulk. The effect of low temperature annealing of ribbons with the coarse grain structure (> 70 nm) was the increasing of coercivity, it also increased the Curie temperature of 1: 5 phase and resistivity. The effect of low temperature annealing on the coercivity of high energy milled powders with a smaller grain size (< 70 nm) was different from the ribbons. The maximum coercivity of 21 kOe was obtained for 3h milled powders annealed at 400°C for 1 h. However, after longer annealing the coercivity decreases and this is different behavior from bulk. The effect of annealing on the homogenized crushed powders (>140nm) was more like bulk, even after annealing for 50 h at 400°C coercivity obtained was 38.48 kOe and increasing. (Abstract shortened by UMI.)

Quadratic electromechanical strain in silicon investigated by scanning probe microscopy

NASA Astrophysics Data System (ADS)

Yu, Junxi; Esfahani, Ehsan Nasr; Zhu, Qingfeng; Shan, Dongliang; Jia, Tingting; Xie, Shuhong; Li, Jiangyu

2018-04-01

Piezoresponse force microscopy (PFM) is a powerful tool widely used to characterize piezoelectricity and ferroelectricity at the nanoscale. However, it is necessary to distinguish microscopic mechanisms between piezoelectricity and non-piezoelectric contributions measured by PFM. In this work, we systematically investigate the first and second harmonic apparent piezoresponses of a silicon wafer in both vertical and lateral modes, and we show that it exhibits an apparent electromechanical response that is quadratic to the applied electric field, possibly arising from ionic electrochemical dipoles induced by the charged probe. As a result, the electromechanical response measured is dominated by the second harmonic response in the vertical mode, and its polarity can be switched by the DC voltage with the evolving coercive field and maximum amplitude, in sharp contrast to typical ferroelectric materials we used as control. The ionic activity in silicon is also confirmed by the scanning thermo-ionic microscopy measurement, and the work points toward a set of methods to distinguish true piezoelectricity from the apparent ones.

Study of reversible magnetization in FeCoNi alloy nanowires with different diameters by first order reversal curve (FORC) diagrams

NASA Astrophysics Data System (ADS)

Samanifar, S.; Kashi, M. Almasi; Ramazani, A.

2018-05-01

Magnetic nanowires electrodeposited into solid templates are of high interest due to their tunable properties which are required for magnetic recording media and spintronic devices. Here, highly ordered arrays of FeCoNi NWs with varied diameters (between 60 and 150 nm) were fabricated into nanopores of hard-anodized aluminum oxide templates using pulsed ac electrodeposition technique. X-ray diffraction patterns indicated the formation of FeCoNi NWs with fcc FeNi and bcc FeCo alloy phases, being highly textured along the bcc [110] direction. Magnetic properties were studied by hysteresis loop measurements at room temperature and they showed reductions in coercivity and squareness values by increasing diameter. First-order reversal curve measurements revealed that, with increasing diameter from 60 to 150 nm, besides a transition from a single domain (SD) state to a pseudo SD state, an increase in the reversible magnetization component of the NWs from 11% to 24% occurred.

A comparison of peer and non-peer exposure to unwanted early sexual experiences among students in South Africa and Belgium.

PubMed

Revell, Arlynn T; Nicholas, Lionel J

2013-01-01

This study examined peer and non-peer unwanted early sexual experiences (UESE) among 3,689 university students to establish whether peer UESE is as coercive and bothersome as non-peer UESE. A self-report checklist was administered to all consenting students attending an orientation programme at one South African (SA) and one Belgian university. Of the respondents 21% indicated that they had UESE before their 16th birthday (39.2% SA and 13.5% Belgians). Of respondents indicating UESE, 22.4% (173) reported that they had UESE with a person where the age difference was greater than 5 years and 54.2% (418) reported UESE with an age difference less than 5 years. Overall, a statistically significant difference was found between peer exposed and non-peer exposed groups at the time the UESE occurred related to bothersomeness of the UESE. SA men and women experienced more psychological pressure or physical force among the non-peer exposed group than the peer exposed group.

Synthesis and Magnetic Properties of Fe-Co-Ni/C Nanocomposites

NASA Astrophysics Data System (ADS)

Muratov, D. G.; Kozhitov, L. V.; Karpenkov, D. Yu.; Yakushko, E. V.; Korovin, E. Yu.; Vasil'ev, A. V.; Popkova, A. V.; Kazaryan, T. M.; Shadrinov, A. V.

2018-03-01

Nanoparticles of the Fe-Co-Ni ternary alloy, encapsulated in the carbon matrix of nanocomposites, have been synthesized, The structure, phase composition, and magnetic properties of the obtained materials have been determined with the help of diffractometry and magnetometry. It has been established that nanoparticles of the ternary alloy are formed due to solution of cobalt in the Fe-Ni alloy. The composition of the nanoparticles of the alloy depends on the mass percent ratio of the metas in the precursor. With growth of the iron content, nanoparticles of the ternary alloy with various composition are formed with FCC and BCC crystal lattice structure. As the synthesis temperature and relative iron content are increased, the magnetization of the Fe-Co-Ni/C nanocomposites increases from 26 to 157 A·m2/kg. The coercive force is determined by the synthesis temperature, the size of the nanoparticles, and the composition of the alloy, and its value varies from 330 to 43 Oe.

Ferroelectric, piezoelectric, and leakage current properties of (K0.48Na0.48Li0.04)(Nb0.775Ta0.225)O3 thin films grown by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Wang, D. Y.; Lin, D. M.; Kwok, K. W.; Chan, N. Y.; Dai, J. Y.; Li, S.; Chan, H. L. W.

2011-01-01

Lead-free (K0.48Na0.48Li0.04)(Nb0.775Ta0.225)O3 (KNLNT) thin films were deposited on Pt(111)/Ti/SiO2/Si(001) substrates using pulsed laser deposition. The film exhibited a well-defined ferroelectric hysteresis loop with a remnant polarization 2Pr of 22.6 μC/cm2 and a coercive field Ec of 10.3 kV/mm. The effective piezoelectric coefficient d33,f of the KNLNT thin films was found to be about 49 pm/V by piezoelectric force microscope. The dominant conduction mechanisms of Au/KNLNT/Pt thin film capacitor were determined to be bulk-limited space-charge-limited-current and Poole-Frenkle emission at low and high electric field strengths, respectively, within a measured temperature range of 130-370 K.

Archaeointensity and rock magnetism on Maya locations pottery, Southeast Mexico, from Preclassic to Posclassic

NASA Astrophysics Data System (ADS)

Rodriguez Trejo, A.; Alva-Valdivia, L. M.; Nieto Calleja, R.; Jimenez, S.

2016-12-01

Archeointensity results are presented from 7 archeological sites of the Maya Zone, southeast Mexico: Chiapas, Yucatan and Quintana Roo, distributed geographically over a 500,000 Km2 area over the Yucatan Peninsula. The sites corresponds to over 250 samples from Palenque, Chichén-Itzá, Flor de Mayo, El Mirador, Oxtancah, Busiljá and Mensabak. All the artifact sites correspond from the Preclasic to Posclasic period (1000 b.C. to 1600 a.C.), which represent the most important period in Mesoamerica. The laboratory experiments for rock magnetism includes the suscpetibility vs. temperature curves (KT), hysteresis loop, first order reversal curves analysis (FORC), IRM coercivity unmixing and thermal and AF demagnetization. Archaeointensity were carried out using previously selected samples that accomplish the quality criteria, using the Thellier - Thellier methology and the Coe check modification. These results will be used to construct a secular variation curve for intensity in this region, which eventually could be used for dating many archeological materials of unknown age.

Prevalence and meanings of exchange of money or gifts for sex in unmarried adolescent sexual relationships in sub-Saharan Africa

PubMed Central

Moore, Ann M.; Biddlecom, Ann E.; Zulu, Eliya M.

2008-01-01

Using national survey data collected in 2004 in Burkina Faso, Ghana, Malawi, and Uganda with 12–19 year olds, we examine the prevalence of sex in exchange for money or gifts in the 12 months prior to the survey and its association with adolescents’ social and economic vulnerability and condom use. Receiving something in exchange for sex is very common among sexually active, unmarried female adolescents and there are no significant differences by household economic status, orphan status, level of schooling completed or age difference between partners. Condom use at last sex in the 12 months prior to the survey is not associated with receiving gifts or money. Qualitative data based on focus group discussions and in-depth interviews collected in 2003 with adolescents suggest that receiving money or gifts for sex is not necessarily a coercive force, but rather can be a routine aspect of dating. PMID:18458736

Delayed demagnetization jumps in (NdDy)(FeCo)B magnets in a steady-state magnetic field

NASA Astrophysics Data System (ADS)

L'vova, G. L.; Kirman, M. V.; Koplak, O. V.; Kucheryaev, V. V.; Valeev, R. A.; Piskorskii, V. P.; Morgunov, R. B.

2017-11-01

Spontaneous demagnetization jumps are observed in sintered magnets (Nd0.6Dy0.4)16(Fe0.77Co0.23)78B6 in a constant magnetic field after a sharp decrease in an external magnetic field from the value corresponding to the saturation to a value close to the coercive force. It is shown that the number of the magnetization jumps is proportional to their amplitudes. A low value of the autocorrelation coefficient between the jump amplitude and the time of its appearance ( R < 0.1) demonstrate the stochasticity of the jumps. It is found that the spectral jump density is independent of the frequency, i.e., a white magnetic noise is observed. The distribution of the magnetic field gradient has been obtained near the sample surface that makes it possible to distinguish domains and the grain magnetization in the dependence on the direction of the texturing of the sintered magnet.

Structural and DC electrical resistivity, magnetic properties of Co0.5M0.5Fe2O4 (M= Ni, Zn, and Mg) ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Ramakrishna, A.; Murali, N.; Mammo, Tulu Wegayehu; Samatha, K.; Veeraiah, V.

2018-04-01

Inverse spinel structured nanoparticles of cobalt ferrite partially substituted by divalent cations of Ni, Zn, and Mg have been synthesized through sol-gel auto combustion route. Structural parameters are studied by powder X-ray diffraction at the diffraction angle range of 10-80°; and FT-IR spectroscopy in the wavenumber range of 1600-400 cm-1. Lattice parameters were calculated from the (hkl) values of the diffraction planes and interplanar spacing and found to be in the range of 8.3659-8.4197 Å. The surface morphology and crystalline nature are studied using scanning electron microscopy and also using HRTEM. The magnetic properties are analyzed through vibrating sample magnetometer. High saturation magnetization of 90.12 emu/g has been achieved from Co-Zn sample whereas high coercive force of 883.45 Oe is achieved in Co-Ni sample. A two-probe DC resistivity was measured in temperature ranges of 300-450 K.

Family therapy for conduct disorders.

PubMed

Sholevar, G P

2001-07-01

Low levels of parental skill and cooperation are the prominent roots of arrested socialization, and a lack of appreciation for intimate and gratifying human relationships is evident in children with CD. The relational problems are exaggerated further by the child's observation of chronic parental discord and internalization of a family image constructed around intrafamilial conflict and isolation. Skills deficits in parental and marital communication and problem solving and conflicts in these relationships play significant roles in producing family dysfunction. The low level of parental differentiation and identity formation plays a fundamental role in family dysfunction by interfering with the development of an adequate self-image, self-esteem, and internal codes of behavior in the child. The transmission of parental antisocial tendencies to their children is facilitated by the low level of differentiation between parent and child. Family treatment should focus on enhancing cooperation between parents and children and between parents as co-parents and as a couple. Enhancing parent management skills can undermine the use of coercive, punitive, and impulsive interactions in the families. The higher divorce rate in parents of children with CD should be addressed with parents directly and early in treatment with the hope of mobilizing the rehabilitative and cooperative marital forces. In terms of future directions, family studies should address and incorporate the expanding knowledge of biologic and psychologic characteristics of children with CD and the possible impact of such characteristics in undermining family development and integrity. Such investigations should include the following information: The role of sustained and intense aggression in some children on family functioning and development. The possible role of diminished response to punishment and excessive search for gratification in children with CD. The role of the child with CD in promoting marital and family discord and divorce. The role of neurotransmitters (such as serotonin) in the production of irritability, provocativeness, coercive family processes, and subsequent depression in the caregiver or the child. Effective models of intervention with children with CD in hospitals and residential treatment centers.

XMCD and TEM studies of as-cast and rapidly quenched Fe50Nd50 alloys

NASA Astrophysics Data System (ADS)

Menushenkov, V. P.; Menushenkov, A. P.; Shchetinin, I. V.; Wilhelm, F.; Ivanov, A. A.; Rudnev, I. A.; Ivanov, V. G.; Rogalev, A.; Savchenko, A. G.; Zhukov, D. G.; Rafalskiy, A. V.; Ketov, S. V.

2017-12-01

We present the XMCD analysis of as-cast and melt spun Fe50Nd50 samples performed at L2,3 -Nd and K-Fe absorption edges at 5 and 50 K in comparison with macroscopic data of XRD, TEM and magnetic properties measurements. In addition, we have measured the magnetic field dependence of XMCD signal for both types of the samples in magnetic fields up/down to 17 T. The obtained results pointed to the strong difference between structure and magnetic properties of the as-cast and melt spun Fe50Nd50 alloys for both macroscopic and local measurements. The element selective XMCD loops for melt spun alloy show almost identical value of the coercive force Hci for L 2-Nd and K-Fe edges and practically do not depend on temperature. XMCD loop at K-Fe edge is a sum of contributions of the Fe-based phases. The main Fe-rich phase has high Hci ≈ 2,4 T as a highly anisotropic phase. The absence of the K-Fe XMCD loop saturation in the field up to 17 T points to presence of the second Nd-rich Nd-Fe phase which is ferromagnetic at temperature lower than 50 K. In accordance to the TEM results these both phases may coexist as the mixture of nanocrystals which was formed as a result of decomposition of the amorphous-like matrix phase. The XMCD loop at L2 -Nd edge with Hci ≈ 1,9 T is the sum of contributions from two Nd-based phases: hard Fe-rich phase (Hci ≈ 2,4 T) and Nd-Fe matrix phase of medium hardness with Hci ≈ 1,3 T. The macroscopic loop showed the higher Hci compared to XMCD loops. Such discrepancy may be caused by the fact that XMCD signal is collected from a 5-10 mcm thick surface layer, which contains many defects that reduce anisotropy and coercivity.

The role of economic factors on women's risk for intimate partner violence: a cross-national comparison of Canada and the United States.

PubMed

Kaukinen, Catherine Elizabeth; Powers, Ráchael A

2015-02-01

National data from Canada and the United States are used to examine the connection between women's economic contributions to the family and their risk for physical and emotional abuse. Analyses show that American women are at a twofold greater risk; however, the relationship between economic variables and the risk of both physical violence and coercive control are more complex. Income serves to reduce the risk of both violence and coercive control for both Canadian and American women, whereas education serves as a clear protective factor for American women, but does not provide the same benefit for Canadian women. © The Author(s) 2014.

Coercivity of domain wall motion in thin films of amorphous rare earth-transition metal alloys

NASA Technical Reports Server (NTRS)

Mansuripur, M.; Giles, R. C.; Patterson, G.

1991-01-01

Computer simulations of a two dimensional lattice of magnetic dipoles are performed on the Connection Machine. The lattice is a discrete model for thin films of amorphous rare-earth transition metal alloys, which have application as the storage media in erasable optical data storage systems. In these simulations, the dipoles follow the dynamic Landau-Lifshitz-Gilbert equation under the influence of an effective field arising from local anisotropy, near-neighbor exchange, classical dipole-dipole interactions, and an externally applied field. Various sources of coercivity, such as defects and/or inhomogeneities in the lattice, are introduced and the subsequent motion of domain walls in response to external fields is investigated.

[Seclusion and mechanical restraints in psychiatric care: Prescriptions procedures, pharmacological management, and monitoring].

PubMed

Tezenas du Montcel, Chloé; Kowal, Célia; Leherle, Audrey; Kabbaj, Soraya; Frajerman, Ariel; Le Guen, Emmanuel; Hamdani, Nora; Schürhoff, Franck; Leboyer, Marion; Pelissolo, Antoine; Pignon, Baptiste

2018-04-18

We will briefly summarize the French recommendations concerning the use of seclusion and mechanical restraint. Acute agitation and aggression or self-injurious activity during psychotic and manic episodes are the main indication of prescription of the coercive measures. Their prescriptions respect specific modalities that will be explained. Although they proved to be efficient, seclusion and restrain need to stay a last resort option, considering the risk of physical complications and psychological consequences. Specific pharmacological prescription will necessarily be associated with coercive measures and we present prescription guidelines. Finally, physical complications need to be prevented and we submit specific protocol concerning constipation and thromboembolic risk management. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Magnetic and Dielectric Investigations of Mn-Doped Ba Hexaferrite Nanoparticles by Hydrothermal Approach

NASA Astrophysics Data System (ADS)

Adeela, N.; Khan, U.; Iqbal, M.; Riaz, S.; Ali, H.; Maaz, K.; Naseem, S.

2016-11-01

A hydrothermal method followed by heat treatment was used to synthesize Mn-substituted Ba2Co2- x Mn x Fe12O22 nanoparticles with a nominal chemical composition of 0 ≤ x < 1 and step gap of 0.3. In this study, the effect of Mn substitution on Co2Y-type barium hexaferrite is investigated after employing x-ray diffraction for crystal structure, field emission scanning electron microscopy for morphology, energy dispersive analysis of x-ray spectroscopy for elemental composition, Fourier transform infrared spectroscopy to confirm bond modes, and vibrating sample magnetometry for magnetic measurements. It was found that the sample at x = 0.9 is of particular interest due to its large coercivity and anisotropy. Later on, for x = 0.9, temperature-dependent magnetic analyses including hysteresis loops, zero-field-cooled, and field-cooled at a particular field of 100 Oe were performed. The decreasing trend in saturation magnetization with increase in temperature was estimated. On the other hand, first an increase and then decrease in coercivity values were observed. These loops also revealed dependence of coercivity on magneto-crystalline anisotropy and average crystallite size of nanoparticles. Dielectric measurements at x = 0.9 make it suitable for high frequency applications.

Phase transformation in rapidly quenched Fe-Cr-Co-Mo-Ti-Si-B alloys

NASA Astrophysics Data System (ADS)

Zhukov, D. G.; Shubakov, V. S.; Zhukova, E. Kh; Gorshenkov, M. V.

2018-03-01

The research results of phase transformations in Fe-24Cr-16Co-3Mo-0.2Ti-1Si-B alloys (with a boron content of 1 to 3% by mass) obtained by rapid quenching are presented. The structure formation regularities during the melt spinning and during the subsequent crystallization annealing in rapidly quenched bands of the Fe-Cr-Co-Mo-Ti-Si-B system alloys were studied. The changes in the phase composition of the rapidly quenched Fe-Cr-Co-Mo-Ti- Si-B system alloys after quenching at various quench rates and at different boron concentrations in the alloys are studied. It is shown that during crystallization from an amorphous state, at temperatures above 570 °C, in addition to the α-phase, the σ-phase appears first, followed by the γ-phase. Heat treatment of rapidly quenched bands to high-coercive state was carried out. A qualitative assessment of magnetic properties in a high-coercivity state was carried out. An evaluation of the level of magnetic properties in a high-coercivity state allows us to conclude that the application of a magnetic field during crystallization from an amorphous state leads to anisotropy of the magnetic properties, that is, an anisotropic effect of thermo-magnetic treatment is detected.

Mental Health Nursing, Mechanical Restraint Measures and Patients’ Legal Rights

PubMed Central

Birkeland, Soren; Gildberg, Frederik A.

2016-01-01

Coercive mechanical restraint (MR) in psychiatry constitutes the perhaps most extensive exception from the common health law requirement for involving patients in health care decisions and achieving their informed consent prior to treatment. Coercive measures and particularly MR seriously collide with patient autonomy principles, pose a particular challenge to psychiatric patients’ legal rights, and put intensified demands on health professional performance. Legal rights principles require rationale for coercive measure use be thoroughly considered and rigorously documented. This article presents an in-principle Danish Psychiatric Complaint Board decision concerning MR use initiated by untrained staff. The case illustrates that, judicially, weight must be put on the patient perspective on course of happenings and especially when health professional documentation is scant, patients’ rights call for taking notice of patient evaluations. Consequently, if it comes out that psychiatric staff failed to pay appropriate consideration for the patient’s mental state, perspective, and expressions, patient response deviations are to be judicially interpreted in this light potentially rendering MR use illegitimated. While specification of law criteria might possibly improve law use and promote patients’ rights, education of psychiatry professionals must address the need for, as far as possible, paying due regard to meeting patient perspectives and participation principles as well as formal law and documentation requirements. PMID:27123152

The comprehensiveness of environmental management systems: The influence of institutional pressures and the impact on environmental performance.

PubMed

Phan, Thanh Nguyet; Baird, Kevin

2015-09-01

This study contributes to the EMS literature by providing a more detailed insight into the comprehensiveness of environmental management systems (EMSs) by focusing on the intensity of use of environmental management practices. In addition, the study examines the influence of institutional pressures (coercive, mimetic and normative) on the comprehensiveness of environmental management systems (EMSs), and the impact of EMS comprehensiveness on environmental performance. A mail survey questionnaire was used to collect data from a random sample of Australian senior managers across various industries. Both coercive and normative pressures were found to influence the comprehensiveness of EMSs. Specifically, the pressure exerted by the government, through the creation of appropriate regulatory pressures and public incentives, and by employees, customers, professional groups, the media, and community, influenced the comprehensiveness of the EMS. In addition, organisations with more comprehensive EMSs were found to experience higher levels of environmental performance. With more than 300,000 organisations worldwide adopting EMSs (ISO, 2013), the findings provide an important insight into the relevance of EMSs. In particular, it is suggested that organisations should endeavour to implement a more comprehensive EMS and be conscious of the role that coercive and normative pressures play in influencing the comprehensiveness of their EMSs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of patch borders on coercivity in amorphous rare earth-transition metal thin films

NASA Technical Reports Server (NTRS)

Patterson, G.; Fu, H.; Giles, R. C.; Mansuripur, M.

1991-01-01

The coercivity at the micron scale is a very important property of magneto-optical media. It is a key factor that determines the magnetic domain wall movement and domain reversal. How the coercivity is influenced by a special type of patch borders is discussed. Patch formation is a general phenomenon in growth processes of amorphous rare earth transition metal thin films. Different patches may stem from different seeds and the patch borders are formed when they merge. Though little is known about the exact properties of the borders, we may expect that the exchange interaction at the patch border is weaker than that within a patch, since there is usually a spatial gap between two patches. Computer simulations were performed on a 2-D hexagonal lattice consisting of 37 complete patches with random shape and size. From the series of simulations we may conclude that the domain in the patch with borders of 30 percent exchange strength can expand most easily to the whole lattice, because the exchange strength can expand most easily to the whole lattice, because the exchange strength of the border is not too high to prevent the domain from growing within the patch and it is not too low to prevent the domain from expanding beyond the patch.

South African women's conceptualisations of and responses to sexual coercion in relation to hegemonic masculinities.

PubMed

Stern, Erin; Buikema, Rosemarie; Cooper, Diane

2016-01-01

Despite the documented relationship between hegemonic norms of masculinities and South African men's use of sexual violence, less is known about how women's engagement with norms of masculinity influences their agency in sexually coercive experiences. This study applied a narrative approach to assess how women's understandings of hegemonic male norms affected their perceptions of and responses to sexually coercive experiences. Twenty-five sexual history narrative interviews were conducted with women across five South African provinces representing a range of ages, language and sociocultural backgrounds. Interviews elicited stories of first experiences of sex and the range of sexual relationships through adulthood. Data were analysed using principles of thematic and narrative analysis. Coercive sexual experiences informed many women's normative ideas about men's sexuality including being impulsive, controlling and aggressive. This could underpin women's limited ability to exercise agency and their increased vulnerability to sexual abuse. Some women reported levels of trust and respect in subsequent relationships, which typically involved deconstructing norms of men's use of coercion and moving beyond self-blame and guilt. The findings highlight the need to appreciate the fluid and situated nature of women's agency from a relational perspective in terms of how women condone and challenge gender norms that support men's use of sexual violence in their relationships.

CoPtB(O) alloy films as new perpendicular recording media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayashi, K.; Hayakawa, M.; Ohmori, H.

In search of new hard magnetic materials with high saturation magnetization and large coercivity, a comprehensive study was made on numerous Co- and CoPt-base crystalline alloys by means of sputtering techniques. It revealed that a newly found CoPtB(O) alloy system possessed excellent hard magnetic properties with remarkably large perpendicular coercivity and high saturation magnetization. This new alloy film, deposited onto room temperature substrates, shows the magnetic properties of 4{pi}{ital M}{sub {ital s}}=12 kG, {ital H}{sup {perpendicular}}{sub {ital c}}=4000 Oe, and perpendicular anisotropy field {ital H}{sub {ital k}}=22 kOe. These values are superior to those of prevailing materials such as CoCrmore » perpendicular and CoPt or CoNi longitudinal recording media. The typical composition is Co{sub 69}Pt{sub 20}B{sub 6}O{sub 5} (at. %), and oxygen plays a momentous role on the coercivity in this alloy film. As a magnetic recording medium, a write/read experiment of this film shows that the readout signal has a +9 dB peak-to-peak amplitude compared with that of metal particle tape at 1 {mu}m wavelength and has +10 dB compared with that of a CoCr perpendicular medium at 0.5 {mu}m wavelength.« less

Micromagnetic simulation and the angular dependence of coercivity and remanence for array of polycrystalline nickel nanowires

NASA Astrophysics Data System (ADS)

Fuentes, G. P.; Holanda, J.; Guerra, Y.; Silva, D. B. O.; Farias, B. V. M.; Padrón-Hernández, E.

2017-02-01

We present here our experimental results for the preparation and characterization of nanowires of nickel and the analysis of the angular dependence of coercivity and remanence using experimental data and micromagnetic simulation. The fabrication was made by using aluminum oxide membranes as templates and deposited nickel by an electrochemical route. The magnetic measurements showed that coercivity and remanence are dependent of the angle of application of the external magnetic field. Our results are different than that expected for the coherent, vortex and transversal modes of the reversion for the magnetic moments. According to the transmission electron microscopy analysis we can see that our nanowires have not a perfect cylindrical format. That is why we have used the ellipsoids chain model for better understanding the real structure of wires and its relation with the magnetic behavior. In order to generate theoretical results for this configuration we have made micromagnetic simulation using Nmag code. Our numerical results for the realistic distances are in correspondence with the magnetic measurements and we can see that there are contradictions if we assume the transverse reversal mode. Then, we can conclude that structure of nanowires should be taken into account to understand the discrepancies reported in the literature for the reversion mechanism in arrays of nickel nanowires.

Magnetic properties of Sm2(Fe0.95M0.05)17Nx (M=Cr and Mn) anisotropic coarse powders with high coercivity

NASA Astrophysics Data System (ADS)

Ito, Mikio; Majima, Kazuhiko; Shimuta, Toru; Katsuyama, Shigeru; Nagai, Hiroshi

2002-09-01

Sm2(Fe0.95Cr0.05)17Nx and Sm2(Fe0.95Mn0.05)17Nx coarse powders 10-70 mum in size were synthesized by crushing mother alloy ingots into 32-74 mum in particle size and subsequent nitrogenation at 748 K in a flowing mixed gas of 60 vol % H2+40 vol % NH3. The effects of Cr or Mn substitution for Fe on the nitrogenation rate, magnetic properties, and microstructure of the Sm2Fe17Nx hard magnetic material were investigated. Cr and Mn substitution was quite effective for accelerating nitrogenation. When the powders were nitrogenated beyond x=3, amorphous phase formation was observed as the x value increased. The magnetic properties of the nitrogenated powders were significantly improved by Cr and Mn substitution, and these powders also possessed a satisfactory magnetic anisotropy. The maximum coercivity in this study, 0.59 MA/m, was obtained for the Sm2(Fe0.95Mn0.05)17N5.0 powder in spite of its large particle size. The high coercivity of the coarse powders was caused by a cell-like microstructure composed of fine 2-17 crystalline grains 20-30 nm in size surrounded by an amorphous phase.

Hydrothermally-induced changes in mineralogy and magnetic properties of oxidized A-type granites

NASA Astrophysics Data System (ADS)

Nédélec, Anne; Trindade, Ricardo; Peschler, Anne; Archanjo, Carlos; Macouin, Mélina; Poitrasson, Franck; Bouchez, Jean-Luc

2015-01-01

The changes in magnetic mineralogy due to the hydrothermal alteration of A-type granitic rocks have been thoroughly investigated in samples from the granite of Tana (Corsica, France), and compared with other A-type granites: Meruoca (NE Brazil), Bushveld (South Africa), Mount Scott (Wichita Mountains, Oklahoma, USA) and the stratoid hypersolvus granites of Madagascar. The altered red-colored samples and their non-altered equivalents were magnetically characterized by means of magnetic susceptibility measurements, hysteresis loops, remanent coercivity spectra, and Lowrie test. It is shown that hydrothermalization in magnetite-bearing granites is related to the formation of fine-grained magnetite and hematite, and to coeval depletion in the content of primary low-coercive coarse-grained magnetite. These mineralogical changes give typical rock magnetic signatures, namely lower susceptibility magnitudes and anisotropy degrees, prolate AMS (anisotropy of magnetic susceptibility) fabrics and increased coercivities. Optical microscopy and SEM (scanning electronic microscopy) images suggest that the orientation of the secondary magnetic minerals is related to fluid-pathways and micro-fractures formed during the hydrothermal event and therefore may be unrelated to magma emplacement and crystallization fabrics. Changes in magnetic mineralogy and grain-size distribution have also to be considered for any paleomagnetic and iron isotope studies in granites.

Coexistence of ferromagnetism and spin glass freezing in the site-disordered kagome ferrite SrSn2Fe4O11

NASA Astrophysics Data System (ADS)

Shlyk, Larysa; Strobel, S.; Farmer, B.; De Long, L. E.; Niewa, R.

2018-05-01

Single-crystal x-ray diffraction refinements indicate SrSn2Fe4O11 crystallizes in the hexagonal R-type ferrite structure with non-centrosymmetric space group P63mc and lattice parameters a = 5.9541(2) Å, c = 13.5761(5) Å, Z = 2 (R(F) = 0.034). Octahedrally coordinated sites are randomly occupied by Sn and Fe; whereas tetrahedrally coordinated sites are exclusively occupied by Fe, whose displacement from ideal trigonal-bipyramidal coordination causes the loss of inversion symmetry. DC magnetization data indicate SrSn2Fe4O11 single crystals undergo ferro- or ferri-magnetic order below a transition temperature TC = 630 K with very low coercive fields Hc ⊥ = 0.27 Oe and Hc// = 1.5 Oe at 300 K, for applied fields perpendicular and parallel to the c-axis, respectively. The value for TC is exceptionally high, and the coercive fields exceptionally low, among the known R-type ferrites. Enhanced coercivity and thermomagnetic hysteresis suggest the onset of short-range, spin glass order occurs below Tf = 35 K. Optical measurements indicate a band gap of 0.8 eV, consistent with wide-gap semiconducting behavior and a previously established empirical correlation between the semiconducting gap and TC for R-type ferrites based upon Ru.

Rare earth elements and permanent magnets (invited)

NASA Astrophysics Data System (ADS)

Dent, Peter C.

2012-04-01

Rare earth (RE) magnets have become virtually indispensible in a wide variety of industries such as aerospace, automotive, electronics, medical, and military. RE elements are essential ingredients in these high performance magnets based on intermetallic compounds RECo5, RE2TM17 (TM: transition metal), and RE2TM14B. Rare earth magnets are known for their superior magnetic properties—high induction, and coercive force. These properties arise due to the extremely high magnetocrystalline anisotropy made possible by unique 3d-4f interactions between transition metals and rare earths. For more than 40 years, these magnets remain the number one choice in applications that require high magnetic fields in extreme operating conditions—high demagnetization forces and high temperature. EEC produces and specializes in RECo5 and RE2TM17 type sintered magnets. Samarium and gadolinium are key RE ingredients in the powder metallurgical magnet production processes which include melting, crushing, jet milling, pressing, sintering, and heat treating. The magnetic properties and applications of these magnets will be discussed. We will also briefly discuss the past, current, and future of the permanent magnet business. Currently, over 95% of all pure rare earth oxides are sourced from China, which currently controls the market. We will provide insights regarding current and potential new magnet technologies and designer choices, which may mitigate rare earth supply chain issues now and into the future.

Theory of electric creep and electromechanical coupling with domain evolution for non-poled and fully poled ferroelectric ceramics

PubMed Central

Xia, Xiaodong; Wang, Yang; Zhong, Zheng

2016-01-01

Unlike mechanical creep with inelastic deformation, electric creep with domain evolution is a rarely studied subject. In this paper, we present a theory of electric creep and related electromechanical coupling for both non-poled and fully poled ferroelectric ceramics. We consider electric creep to be a time-dependent process, with an initial condition lying on the D (electric displacement) versus E (electric field) hysteresis loop. Both processes are shown to share the same Gibbs free energy and thermodynamic driving force, but relative to creep, the hysteresis loop is just a field-dependent process. With this view, we develop a theory with a single thermodynamic driving force but with two separate kinetic equations, one for the field-dependent loops in terms of a Lorentzian-like function and the other for the time-dependent D in terms of a dissipation potential. We use the 0°–90° and then 90°–180° switches to attain these goals. It is demonstrated that the calculated results are in broad agreement with two sets of experiments, one for a non-poled PIC-151 and the other for a fully poled PZT-5A. The theory also shows that creep polarization tends to reach a saturation state with time and that the saturated polarization has its maximum at the coercive field. PMID:27843406

Structural phase transition of as-synthesized Sr-Mn nanoferrites by annealing temperature

NASA Astrophysics Data System (ADS)

Amer, M. A.; Meaz, T. M.; Attalah, S. S.; Ghoneim, A. I.

2015-11-01

The Sr0.2Mn0.8Fe2O4 nanoparticle ferrites were synthesized by the co-precipitation method and annealed at different temperatures T. XRD, TEM, FT-IR, VSM and Mössbauer techniques were used to characterize the samples. This study proved that the structural phase of nanoferrites was transformed from cubic spinel for T≤500 °C to Z-type hexagonal for T≥700 °C. The structural transformation was attributed to Jahn-Teller effect of the Mn3+ ions and/or atomic disorder existed in the crystal lattice. The obtained spectra and parameters for the samples were affected by the transformation process. The lattice constant a showed a splitting to a and c for T>500 °C. The lattice constant c, grain and crystallite size R, strain, octahedral B-site band position and force constant, Debye temperature, coercivity Hc, remnant magnetization, squareness and magnetic moment, spontaneous magnetization and hyperfine magnetic fields showed increase against T. The lattice constant a, distortion and dislocation parameters, specific surface area, tetrahedral A-site band position and force constant, threshold frequency, Young's and bulk moduli, saturation magnetization Ms, area ratio of B-/A-sites, A-site line width were decreased with T. Experimental and theoretical densities, porosity, Poison ratio, stiffness constants, rigidity modulus, B-site line width and spontaneous magnetization showed dependence on T, whereas Ms and Hc proved dependence on R.

Relationship between microstructural and magnetic properties of PrCo-based films prepared by the vacuum evaporation method

NASA Astrophysics Data System (ADS)

Fersi, R.; Bouzidi, W.; Bezergheanu, A.; Cizmas, C. B.; Bessais, L.; Mliki, N.

2018-04-01

In this work, Ce2Ni7 type structural PrCo-based films were deposited on Si(1 0 0) substrate by ultra-high (UHV) vacuum evaporation process. The structural and magnetic properties of these films have been performed using X-ray diffraction (XRD), atomic force microscopy (AFM), vibrating sample magnetometer (VSM) and magnetic force microscopy (MFM) techniques. Two effects on structural and magnetic properties of PrCo films have been investigated: the effect of the annealing temperature (Ta) and the effect of the variation of the magnetic X-layer thickness. The as deposited PrCo films have a magnetic coercivity (Hc) of about 40-100 Oe. But after annealing at 600 °C, Hc has increased hight about 9.5 kOe for PrCo(X = 20 nm) and 10.2 kOe for PrCo(X = 50 nm) were observed. The magnetic properties were affected by the thickness due to the morphology, also the relationship between the intergrain exchange coupling (IEC), the size and quantity of the PrCo grains. The hight extrinsic properties of Hc = 10.2 kOe, maximum energy product (BH)max of 5.12 MGOe and remanence ratio Mr /Ms = 0.53 are reported for the PrCo(X = 50 nm) films. These properties are highly desirable for extremely high-density magnetic recording media applications.

Domain switching kinetics in ferroelectric-resistive BiFeO3 thin film memories

NASA Astrophysics Data System (ADS)

Meng, Jianwei; Jiang, Jun; Geng, Wenping; Chen, Zhihui; Zhang, Wei; Jiang, Anquan

2015-02-01

We fabricated (00l) BiFeO3 (BFO) thin films in different growth modes on SrRuO3/SrTiO3 substrates using a pulsed laser deposition technique. X-ray diffraction patterns show an out-of-plane lattice constant of 4.03 Å and ferroelectric polarization of 82 µC/cm2 for the BFO thin film in a layer-by-layer growth mode (2D-BFO), larger than 3.96 Å and 51 µC/cm2 for the thin film in the 3D-island formation growth mode (3D-BFO). The 2D-BFO thin film at 300 K shows switchable on/off diode currents upon polarization flipping near a negative coercive voltage, which is nevertheless absent from the above 3D-BFO thin film. From a positive-up-negative-down pulse characterization technique, we measured domain switching current transients as well as polarization-voltage (Pf-Vf) hysteresis loops in both semiconducting thin films. Pf-Vf hysteresis loops after 1 µs-retention time show the preferred domain orientation pointing to bottom electrodes in a 3D-BFO thin film. The poor retention of the domains pointing to top electrodes can be improved considerably in a 2D-BFO thin film. From these measurements, we extracted domain switching time dependence of coercive voltage at temperatures of 78-300 K. From these dependences, we found coercive voltages in semiconducting ferroelectric thin films much higher than those in insulating thin films, disobeying the traditional Merz equation. Finally, an equivalent resistance model in description of free-carrier compensation of the front domain boundary charge is developed to interpret this difference. This equivalent resistance can be coincidently extracted either from domain switching time dependence of coercive voltage or from applied voltage dependence of domain switching current, which drops almost linearly with the temperature until down to 0 in a ferroelectric insulator at 78 K.

Rising to the human rights challenge in compulsory treatment--new approaches to mental health law in Australia.

PubMed

Callaghan, Sascha; Ryan, Christopher J

2012-07-01

To analyse, and explain to Australasian psychiatrists, recent proposed changes to the terms of coercive treatment for mental illness in Tasmania and Victoria and to place the proposals in the context of a broader human rights framework that is likely to impact the future shape of mental health legislation more generally. The Australian law reform proposals are reviewed against the requirements of numerous human rights instruments, including the recently ratified United Nations Convention on the Rights of Persons with Disabilities. Ethical and legal arguments are made to support the proposed changes and to introduce others, taking into account academic commentary on mental health law and recent empirical work on the ability to usefully categorise patients by their likelihood of harm to self and others. The Victorian and Tasmanian draft mental health bills propose a new basis for compulsory psychiatric treatment in Australasia. If they become law, coercive psychiatric treatment could only be applied to patients who lack decision-making capacity. The Tasmanian draft bill also sets a new benchmark for timely independent review of compulsory treatment. However both jurisdictions propose to retain an 'additional harm' test which must be satisfied before patients may be treated without consent. This differs from non-psychiatric cases, where if patients are unable to consent to medical treatment for themselves, they will be entitled to receive coercive treatment if it is in their best interests. The proposed changes under the Tasmanian and Victorian draft mental health bills will ensure that, in line with local and international human rights obligations, only patients who lack decision-making capacity may be coercively treated for mental illness. However the continuing 'additional harm' criteria may breach human rights obligations by imposing a discriminatory threshold for care on patients who are unable to consent to treatment for themselves. This could be avoided by replacing the 'additional harm' test with a 'best interests' test.

Stabilization of the high coercivity {epsilon}-Fe{sub 2}O{sub 3} phase in the CeO{sub 2}-Fe{sub 2}O{sub 3}/SiO{sub 2} nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mantlikova, A., E-mail: mantlikova@fzu.cz; Poltierova Vejpravova, J.; Bittova, B.

2012-07-15

We have investigated the processes leading to the formation of the Fe{sub 2}O{sub 3} and CeO{sub 2} nanoparticles in the SiO{sub 2} matrix in order to stabilize the {epsilon}-Fe{sub 2}O{sub 3} as the major phase. The samples with two different concentrations of the Fe were prepared by sol-gel method, subsequently annealed at different temperatures up to 1100 Degree-Sign C, and characterized by the Moessbauer spectroscopy, Transmission Electron Microscopy (TEM), Powder X-ray Diffraction (PXRD), Energy Dispersive X-ray analysis (EDX) and magnetic measurements. The evolution of the different Fe{sub 2}O{sub 3} phases under various conditions of preparation was investigated, starting with themore » preferential appearance of the {gamma}-Fe{sub 2}O{sub 3} phase for the sample with low Fe concentration and low annealing temperature and stabilization of the major {epsilon}-Fe{sub 2}O{sub 3} phase for high Fe concentration and high annealing temperature, coexisting with the most stable {alpha}-Fe{sub 2}O{sub 3} phase. A continuous increase of the particle size of the CeO{sub 2} nanocrystals with increasing annealing temperature was also observed. - Graphical abstract: The graphical abstract displays the most important results of our work. The significant change of the phase composition due to the variation of preparation conditions is demonstrated. As a result, significant change of the magnetic properties from superparamagnetic {gamma}-Fe{sub 2}O{sub 3} phase with negligible coercivity to the high coercivity {epsilon}-Fe{sub 2}O{sub 3} phase has been observed. Highlights: Black-Right-Pointing-Pointer Research of the stabilization of the high coercivity {epsilon}-Fe{sub 2}O{sub 3} in CeO{sub 2}-Fe{sub 2}O{sub 3}/SiO{sub 2}. Black-Right-Pointing-Pointer Samples with two different concentrations of Fe and three annealing temperatures. Black-Right-Pointing-Pointer Phase transition {gamma}{yields}{epsilon}{yields}({beta}){yields}{alpha} with increasing annealing temperature and particle size. Black-Right-Pointing-Pointer Elimination of the superparamagnetic phases in samples with higher content of Fe. Black-Right-Pointing-Pointer Best conditions for high coercivity {epsilon}-Fe{sub 2}O{sub 3}-higher Fe content and T{sub A}=1100 Degree-Sign C.« less

Structure and magnetic properties of Sm{sub 3}(Fe{sub 0.85}Cr{sub 0.15}){sub 29}N{sub y} alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Shunji; Suzuki, Shinya; Kawasaki, Masahito

1995-11-01

The structure and magnetic properties of Sm{sub 3}(Fe{sub 0.85}Cr{sub 0.15}){sub 29}N{sub y} alloy were investigated. It was found that the alloy had the R{sub 3}(Fe,M){sub 29}-type structure and absorbed 4--5 wt.% of nitrogen which exceeds 4 nitrogen atoms per unit formula. The coercivity of the powder was greatly influenced by the nitrogen content and annealing. The Sm{sub 3}(Fe{sub 0.85}Cr{sub 0.15}){sub 29}N{sub y} alloy powder with 4.1 wt.% of nitrogen showed a high coercivity of 552 kA/m without fine grinding.

Templated assembly of Co-Pt nanoparticles via thermal and laser-induced dewetting of bilayer metal films.

PubMed

Oh, Yong-Jun; Kim, Jung-Hwan; Thompson, Carl V; Ross, Caroline A

2013-01-07

Templated dewetting of a Co/Pt metal bilayer film on a topographic substrate was used to assemble arrays of Co-Pt alloy nanoparticles, with highly uniform particle size, shape and notably composition compared to nanoparticles formed on an untemplated substrate. Solid-state and liquid-state dewetting processes, using furnace annealing and laser irradiation respectively, were compared. Liquid state dewetting produced more uniform, conformal nanoparticles but they had a polycrystalline disordered fcc structure and relatively low magnetic coercivity. In contrast, solid state dewetting enabled formation of magnetically hard, ordered L1(0) Co-Pt single-crystal particles with coercivity >12 kOe. Furnace annealing converted the nanoparticles formed by liquid state dewetting into the L1(0) phase.

Effect of finite size in magnetic properties of BaFe12O19

NASA Astrophysics Data System (ADS)

Kumar, A. Sendil; Bhatnagar, Anil K.

2018-05-01

BaFe12O19 Nanoparticles are prepared through auto ignition method and structure, microstructure and magnetic properties are characterized. Samples having spherical shapes and elongated nanorods are chosen to investigate the role of finite size effect in magnetic properties. Magnetization studies show superparamagnetic, antiferromagnetic and ferrimagnetic behaviors depending on the size and shape. Very small coercive field of around 200 Oe is observed for spherical nanoparticles and a large coercive field of around 7000 Oe for nanorods is found. The shape and size plays an important role in magnetic properties of BaFe12O19 nanoparticles. Shape anisotropy has significant value compared to other anisotropies. Therefore shape of nanoparticles influences the magnetic order.

Atomic-Resolution X-ray Energy-Dispersive Spectroscopy Chemical Mapping of Substitutional Dy Atoms in a High-Coercivity Neodymium Magnet

NASA Astrophysics Data System (ADS)

Itakura, Masaru; Watanabe, Natsuki; Nishida, Minoru; Daio, Takeshi; Matsumura, Syo

2013-05-01

We have investigated local element distributions in a Dy-doped Nd2Fe14B hot-deformed magnet by atomic-column resolution chemical mapping using an X-ray energy-dispersive spectrometer (XEDS) attached to an aberration-corrected scanning transmission electron microscope (Cs-corrected STEM). The positions of the Nd and Dy atomic columns were visualized in the XEDS maps. The substitution of Dy was limited to a surface layer 2-3 unit cells thick in the Nd2Fe14B grains, and the Dy atoms preferentially occupied the 4f-Nd sites of Nd2Fe14B. These results provide further insights into the principal mechanism governing the coercivity enhancement due to Dy doping.

Coercive versus cooperative pollution control: Comparative study of state programs to reduce erosion and sedimentation pollution in urban areas

NASA Astrophysics Data System (ADS)

Burby, Raymond J.

1995-05-01

This article examines coercive and cooperative approaches to implementing state urban erosion and sedimentation pollution control programs. State administrators report serious shortfalls in their ability to control sources of pollution, but comparison of more and less successful programs provides evidence of what states can do to make programs more effective. Key ingredients for a successful state effort include the use of coercion with both the private sector and local government, adequate staffing, application of severe sanctions when violations of state standards are detected, and provision of technical assistance. Many state programs lack one or more of those elements, which explains their inability to adequately control urban erosion and sedimentation pollution.

One-step solution combustion synthesis of pure Ni nanopowders with enhanced coercivity: The fuel effect

NASA Astrophysics Data System (ADS)

Khort, Alexander; Podbolotov, Kirill; Serrano-García, Raquel; Gun'ko, Yurii K.

2017-09-01

In this paper, we report a new modified one-step combustion synthesis technique for production of Ni metal nanoparticles. The main unique feature of our approach is the use of microwave assisted foam preparation. Also, the effect of different types of fuels (urea, citric acid, glycine and hexamethylenetetramine) on the combustion process and characteristics of resultant solid products were investigated. It is observed that the combination of microwave assisted foam preparation and using of hexamethylenetetramine as a fuel allows producing pure ferromagnetic Ni metal nanoparticles with enhanced coercivity (78 Oe) and high value of saturation magnetization (52 emu/g) by one-step solution combustion synthesis under normal air atmosphere without any post-reduction processing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singleton, John; Kim, Jae Wook; Topping, Craig V.

Here, we report extraordinarily large magnetic hysteresis loops in the iridates Sr 3NiIrO 5 and Sr 3CoIrO 6. We find coercive magnetic fields of up to 55 T with switched magnetic moments ≈1μ B per formula unit in Sr 3NiIrO 6 and coercive fields of up to 52 T with switched moments ≈3μ B per formula unit in Sr 3CoIrO 6. We propose that the magnetic hysteresis involves the field-induced evolution of quasi-one-dimensional chains in a frustrated triangular configuration. In conclusion, the striking magnetic behavior is likely to be linked to the unusual spin-orbit-entangled local state of the Ir 4+more » ion and its potential for anisotropic exchange interactions.« less

Evaluating a prevention program for teenagers on sexual coercion: a differential effectiveness approach.

PubMed

Pacifici, C; Stoolmiller, M; Nelson, C

2001-06-01

The authors evaluated a coeducational program for teenagers on preventing sexual coercion in dating situations. Students examined individual and social attitudes underlying coercive sexual behavior and learned communication skills aimed at preventing or dealing with unwanted sexual advances. Instruction was enhanced by video and an interactive video "virtual date." Outcomes were assessed using sexual attitude scales with a sample of 458 high school students. Student health education classes were randomly assigned to either a treatment or a control condition. Findings, based on a latent variable model of differential effectiveness, showed that students in the treatment group with initial coercive attitude scores at or above the mean benefited significantly more than students with the same range of scores in the control group.

Correlates of Sexual Coercion among People Who Inject Drugs (PWID) in Los Angeles and San Francisco, CA.

PubMed

Williams, Jeffery E; Dangerfield, Derek T; Kral, Alex H; Wenger, Lynn D; Bluthenthal, Ricky N

2018-04-03

Experiences of coerced or forced sex have been associated with risk for HIV infection for all adults and may be more common for gays, lesbians, bisexuals (GLB) and people who inject drugs (PWID). In this study, we explored factors associated with prior 12-month experiences of forced or coerced sex among a sample of PWID, with a focus on sexual orientation and gender. PWID (N = 772) from Los Angeles and San Francisco were recruited using targeted sampling methods in 2011-2013 and surveyed on a range of items related to demographics, drug use, HIV risk, and violence, including experiences of forced or coerced sex in the prior 12 months. In this racially/ethnically diverse, mostly homeless, and low-income sample of PWID, 25% of participants were female and 15% identified as GLB. Sexual coercion was reported by 9% of gay and bisexual men, 8% of heterosexual females, 5% of lesbians and bisexual women, and less than 1% of heterosexual men. In multivariate analyses, compared to heterosexual males, gay or bisexual males (adjusted odds ratio [AOR] = 10.68; 95% confidence interval [CI] = 2.03, 56.23), and heterosexual females (AOR = 9.69; 95% CI = 2.04, 45.94) had increased odds of coerced sex in the prior 12 months. Having a paying sex partner (AOR = 3.49; 95% CI = 1.42, 8.54) or having had forced sex prior to the age of 16 by someone at least five years older (AOR = 4.74; 95% CI = 1.88, 11.93) also elevated the odds of coercive sex. Sexual coercion is common among PWID, but especially for gay and bisexual men and heterosexual females. Efforts to reduce sexual violence among PWID are urgently needed.

Synthesis, structural and magnetic behavior studies of Zn-Al substituted cobalt ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Zare, Samad; Ati, Ali A.; Dabagh, Shadab; Rosnan, R. M.; Othaman, Zulkafli

2015-06-01

A series of nano-sized Zn-Al substituted cobalt ferrite Co(1-x)Zn(x)Fe2-xAlxO4 with 0.0 ⩽ x ⩽ 1.0 have been synthesized by chemical co-precipitation technique. The XRD spectra revealed the single phase spinel structure of Co(1-x)Zn(x)Fe2-xAlxO4 with average size of nanoparticles are estimated to be 17-30 nm. These are small enough to achieve the suitable signal to noise ratio, which is important in the high-density recording media. The FTIR spectra show the characteristic of two strong absorption bands at 560-600 cm-1 corresponds to the intrinsic stretching vibrations of the metal at the tetrahedral site and lowest band is observed at 370-410 cm-1 corresponds to octahedral site. The crystalline structures of nanoparticles composite were characterized by Field Emission Scanning Electron Microscopy (FE-SEM). The magnetic properties such as saturation magnetization, remanence magnetization, and coercivity were calculated from the hysteresis loops. Saturation magnetization were found to increase up to x = 0.4 while remanence magnetization and coercivity continuously decrease with increasing Zn-Al concentration. The stability in coercivity while increase in saturation magnetization confirms that the Co0.6Zn0.4Fe1.6Al0.4O4 ferrite sample is suitable for applications in high-density recording media.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, X., E-mail: Xiujuan.jiang@pnnl.gov

Soft magnetic materials are often limited in scalability due to conventional processes that do not retain beneficial microstructures, and their associated physical properties, during densification. In this work, friction consolidation (FC) has been studied to fabricate Fe−Si soft magnetic materials from gas-atomized powder precursors. Fe−Si powder is consolidated using variable pressure and tool rotation speed in an effort to evaluate this unique densification approach for potential improvements in magnetic properties. FC, due to the high shear deformation involved, is shown to result in uniform gradual grain structure refinement across the consolidated workpiece from the center nearest the tool to themore » edge. Magnetic properties along different orientations indicate little, if any, textural orientation in the refined grain structure. The effect of annealing on the magnetic properties is evaluated and shown to decrease coercivity. FC processing was able to retain the magnetization of the original gas-atomized powders but further process optimization is needed to reach the optimal coercivity for the soft magnetic materials applications. - Highlights: •Friction stir processing was utilized to consolidate Fe−Si soft magnetic powders. •The resultant microstructure and magnetic properties were correlated to the processing conditions. •Friction consolidation refined the grain size of the materials by ~ 40%. •Annealing successfully reduced the coercivity induced by the stress during processing. •The results shine light on the possible scaling up of nanostructured materials.« less

Heterogeneity Within Domestic Violence Exposure: Young Adults' Retrospective Experiences.

PubMed

Haselschwerdt, Megan L; Hlavaty, Kathleen; Carlson, Camille; Schneider, Mallory; Maddox, Lauren; Skipper, Megan

2016-06-01

Using Holden's taxonomy of domestic violence (DV) exposure as a guiding framework, the current study examined young adults' diverse DV exposure experiences. Twenty-five young adults (ages 19-25) exposed to father-perpetrated DV during their childhood and adolescence were interviewed using a qualitative descriptive design. Data analyses focused on coercive control exposure through reports of non-physical abuse tactics, types of exposure (e.g., direct, indirect), physical violence exposure (e.g., severity, frequency), and child abuse and harsh parenting practices. DV-exposed young adults were directly and indirectly exposed to physical violence and an array of non-physical abuse tactics toward their mothers. Young adults categorized as having been exposed to coercive controlling violence reported exposure to ongoing, non-physical abuse tactics and more frequent and severe physical violence. These young adults were also more likely to intervene and become victimized during physical violence and reported repeated episodes of child abuse and harsh parenting. Although coercive control appeared to be associated with physical violence and child abuse, generalizations should be made with caution as a few participants exposed to situational conflict were exposed to frequent and severe DV. The findings suggest that DV exposure should be measured in methodologically sophisticated ways to capture the heterogeneity in experiences, with the goal of promoting empirically driven intervention and prevention initiatives that are tailored to individual and family needs. © The Author(s) 2016.

Nanocomposite Nd-Y-Fe-B-Mo bulk magnets prepared by injection casting technique

NASA Astrophysics Data System (ADS)

Tao, Shan; Ahmad, Zubair; Zhang, Pengyue; Yan, Mi; Zheng, Xiaomei

2017-09-01

The phase composition, magnetic and microstructural properties of Nd2Fe14B/(α-Fe, Fe3B) nanocomposite magnets produced by injection casting technique have been studied. Magnetic hysteresis loop of the Nd7Y6Fe61B22Mo4 permanent magnet demonstrates the coercivity as high as 1289 kA/m. Electron microscopy elucidates a microstructure composed of magnetically soft α-Fe, Fe3B and hard Nd2Fe14B/Y2Fe14B nanograins (20-50 nm) separated by ultra-thin grain boundary layer. The Henkel plot curve of the Nd7Y6Fe61B22Mo4 magnet yields the existence of exchange coupling interactions between soft and hard phases. Macroscopically large size sheet magnet is obtained due to high glass forming ability of the Nd7Y6Fe61B22Mo4 alloy derived from large atomic radius mismatch and negative enthalpy of alloy constituent elements. The high coercivity of the magnet is attributed to the magnetically hard phase increment, nucleation of reverse domains and the presence of thin grain boundary phase. Good magnetic properties such as remanence of 0.51 T, coercivity of 1289 kA/m and maximum energy product of 46.2 kJ/m3 are obtained in directly casted Nd7Y6Fe61B22Mo4 sheet magnets.

Parenting and the Family Check-Up: Changes in Observed Parent-Child Interaction Following Early Childhood Intervention

PubMed Central

Sitnick, Stephanie L.; Shaw, Daniel S.; Gill, Anne; Dishion, Thomas; Winter, Charlotte; Waller, Rebecca; Gardner, Frances; Wilson, Melvin

2016-01-01

Coercion theory posits a cyclical relationship between harsh and coercive parent–child interactions and problem behavior beginning in early childhood. As coercive interactions have been theorized and found to facilitate the development and growth of early conduct problems, early interventions often target parenting to prevent or reduce early disruptive problem behavior. This study utilizes direct observations of parent–child interactions from the Early Steps Multisite study (N = 731; 369 boys) to examine the effect of the Family Check-Up, a family-centered intervention program, on measures of parent–child positive engagement and coercion from age 2 through 5, as well as on childhood problem behavior at age 5. Results indicate that high levels of parent–child positive engagement were associated with less parent–child coercion the following year, but dyadic coercion was unrelated to future levels of positive engagement. In addition, families assigned to the Family Check-Up showed increased levels of positive engagement at ages 3 and 5, and the association between positive engagement at age 3 and child problem behavior at age 5 was mediated by reductions in parent–child coercion at age 4. These findings provide longitudinal confirmation that increasing positive engagement in parent–child interaction can reduce the likelihood of coercive family dynamics in early childhood and growth in problem behavior. PMID:25133754

Parenting and the Family Check-Up: Changes in Observed Parent-Child Interaction Following Early Childhood Intervention.

PubMed

Sitnick, Stephanie L; Shaw, Daniel S; Gill, Anne; Dishion, Thomas; Winter, Charlotte; Waller, Rebecca; Gardner, Frances; Wilson, Melvin

2015-01-01

Coercion theory posits a cyclical relationship between harsh and coercive parent-child interactions and problem behavior beginning in early childhood. As coercive interactions have been theorized and found to facilitate the development and growth of early conduct problems, early interventions often target parenting to prevent or reduce early disruptive problem behavior. This study utilizes direct observations of parent-child interactions from the Early Steps Multisite study (N = 731; 369 boys) to examine the effect of the Family Check-Up, a family-centered intervention program, on measures of parent-child positive engagement and coercion from age 2 through 5, as well as on childhood problem behavior at age 5. Results indicate that high levels of parent-child positive engagement were associated with less parent-child coercion the following year, but dyadic coercion was unrelated to future levels of positive engagement. In addition, families assigned to the Family Check-Up showed increased levels of positive engagement at ages 3 and 5, and the association between positive engagement at age 3 and child problem behavior at age 5 was mediated by reductions in parent-child coercion at age 4. These findings provide longitudinal confirmation that increasing positive engagement in parent-child interaction can reduce the likelihood of coercive family dynamics in early childhood and growth in problem behavior.

Relative Employment, Gender Beliefs, and Intimate Partner Coercion and Violence Against New Mothers Across Marital and Residential Contexts.

PubMed

Zito, Rena C

2017-06-01

This research builds on prior studies of intimate partner victimization by examining the impact of women's and men's relative employment, gender traditionalism, and gender distrust on coercive control and physical victimization among married, cohabiting, and noncohabiting couples with infants. It merges feminist approaches that emphasize the gendered meaning of work, power, and violence with prior insights regarding differences in levels of intimate violence across family forms. Specifically, this research recognizes that there is variation across married, cohabiting, and dating contexts in the symbolic meaning of work, the salience of traditionalism, and the tenuous status of relationships that may activate gender distrust in the production of compensatory violence and control. Logistic regression models using baseline and Year 1 Fragile Families and Child Well-Being data ( n = 2,337) indicate that the predictors of coercive control differ across couple types, with the relative odds of coercion higher among couples in which only the woman is employed, but only when cohabiting. Consistent with expectations, men's gender traditionalism increases coercive control, but only in the context of marriage. Relative employment and gender beliefs did not predict physical victimization among any couple types, but a moderating effect of men's gender distrust on women's sole employment was identified, such that status inconsistency in employment increases the relative odds of physical victimization only when the male partner is distrustful of women.

Prevalence and risk factors for the use of restraint in psychiatry: a systematic review.

PubMed

Beghi, Massimiliano; Peroni, Federica; Gabola, Piera; Rossetti, Aurora; Cornaggia, Cesare Maria

2013-01-01

Despite the poor evidence supporting the use of coercive procedures in psychiatry wards and their "psychological damage" on patients, the practice of restraint is still frequent (6-17%) and varies 10-20 times among centers. We searched the PubMed, Embase, and PsychInfo databases for papers published between January 1 1990 and March 31 2010 using the key words "restraint", "constraint", "in-patient" and "psychiatry wards" and the inclusion criteria of adult samples (studies of selected samples such as a specific psychiatric diagnosis other than psychosis, adolescence or the elderly, men/women only, personality disorders and mental retardation were excluded), the English, French, Italian or German languages, and an acute setting. The prevalence of the use of restraint was 3.8-20% (not different from previous data), despite the attempts to reduce the use of restraint. The variables most frequently associated with the use of coercive measures in the 49 studies included in this review were male gender, young adult age classes, foreign ethnicity, schizophrenia, involuntary admission, aggression or trying to abscond, and the presence of male staff. Coercive measures are still widely used in many countries (albeit to a greater or lesser extent) despite attempts to introduce alternatives (introduction of special protocols and nurses' training courses) in some centers that should really be tested in large-scale multicenter studies in order to verify their efficacy.

The effect of temperature on the structure and magnetic properties of Co0.5Ni0.5Fe2O4 spinel nanoferrite

NASA Astrophysics Data System (ADS)

Abdallah, Hafiz M. I.; Moyo, Thomas; Ngema, Nokwanda

2015-11-01

Nanocrystalline Co0.5Ni05Fe2O4 ferrite with average crystallite size of 7.6 nm and lattice constant of 0.8372 nm was synthesized via a glycol-thermal process. The structure parameters and morphology of the as-synthesized sample and annealed samples were characterized by XRD, EDX, FTIR, HRSEM and HRTEM. The hyperfine interactions, iron distribution on the tetrahedral and octahedral sites for the as-synthesized sample and samples annealed at 500 °C were deduced by Mössbauer spectroscopy measurements at 300 K. The magnetization measurements for the as-synthesized and annealed samples (300-900 °C) were obtained by a vibrating sample magnetometer on a cryogen free measurement system at different isothermal temperatures (4-300 K) in external applied magnetic fields of ±5 T. The temperature dependence of the magnetic properties such as coercive field, saturation magnetization, remanent magnetization and squareness of hysteresis loops were investigated. The sample transformed from single-domain to multi-domain configuration at particle size of about 31 nm. At 300 K, the sample annealed at 700 °C exhibits a maximum coercivity. The as-prepared sample shows a substantial increase in coercivity from 0.182 kOe at 300 K to 6.018 kOe at 4 K.

EFFECT OF PRE-ALLOYING CONDITION ON THE BULK AMORPHOUS ALLOY ND(60)FE(30)AL(10).

DOE Office of Scientific and Technical Information (OSTI.GOV)

OCONNOR,A.S.; LEWIS,L.H.; MCCALLUM,R.W.

Bulk metallic glasses are materials that require only modest cooling rates to obtain amorphous solids directly from the melt. Nd{sub 60}Fe{sub 30}Al{sub 10} has been reported to be a ferromagnetic bulk metallic glass that exhibits high coercivity, a combination unlike conventional Nd-based amorphous magnetic alloys. To clarify the relationship between short-range order and high coercivity in glassy Nd{sub 60}Fe{sub 30}Al{sub 10}, experiments were performed to verify the existence of a homogeneous liquid state prior to rapid solidification. Alloys were prepared by various pre-alloying routes and then melt-spun. Arc-melted alloys were prepared for melt spinning using three different protocols involving: (1)more » alloying all three elements at once, (2) forming a Nd-Fe alloy which was subsequently alloyed with Al, and (3) forming a Fe-Al alloy for subsequent alloying with Nd. XRD, DTA, and magnetic measurement data from the resultant ribbons indicate significant differences in both the glassy fraction and the crystalline phase present in the as-spun material. These observed differences are attributed to the presence of highly stable nanoscopic aluminide-and/or silicide-phases, or motes, present in the melt prior to solidification. These motes would affect the short-range order and coercivity of the resultant glassy state and are anticipated to provide heterogeneous nucleation sites for crystallization.« less

Structure and magnetic properties of mechanically alloyed Co and Co-Ni

NASA Astrophysics Data System (ADS)

Guessasma, S.; Fenineche, N.

The influence of milling process on magnetic properties of Co and Co-Ni materials is studied. Coercivity, squareness ratio and crystallite size of mechanically alloyed Co-Ni material were related to milling time. For Co material, coercivity, cubic phase ratio and crystallite size were related to milling energy considering the vial and plateau rotation velocities. An artificial neural network (ANN) combining the parameters for both materials is used to predict magnetic and structure results versus milling conditions. Predicted results showed that milling energy is mostly dependent on the ratio vial to plateau rotation velocities and that milling times larger than 40 h do not add significant change to both structure and magnetic responses. Magnetic parameters were correlated to crystallite size and the D 6 law was only valid for small sizes.

Grain boundary diffusion behaviors in hot-deformed Nd2Fe14B magnets by PrNd-Cu low eutectic alloys

NASA Astrophysics Data System (ADS)

Tang, Xu; Chen, Renjie; Li, Ming; Jin, Chaoxiang; Yin, Wenzong; Lee, Don; Yan, Aru

2018-01-01

High coercivity of hot-deformed Nd2Fe14B magnets was obtained by grain boundary diffusion. Comparable squareness and similar magnetic properties for samples diffusing from side and pole surfaces show little discrepancies if quantities of the infiltrated PrNd-Cu low eutectic alloys is enough to obtain sufficient diffusion. However, the microstructures and higher characteristic peak ratios show preferable orientation of grains near surfaces of the sample diffused from side surfaces than that from pole surfaces. Amorphous Nd-rich phases and crystal Fe-rich phases were both observed in the diffused magnets. The enhancement of coercivity is considered to be resulted from grain boundary optimization and magnetic isolation which is caused by the thickened nonmagnetic intergranular phases.

Evolutionary instability of zero-determinant strategies demonstrates that winning is not everything.

PubMed

Adami, Christoph; Hintze, Arend

2013-01-01

Zero-determinant strategies are a new class of probabilistic and conditional strategies that are able to unilaterally set the expected payoff of an opponent in iterated plays of the Prisoner's Dilemma irrespective of the opponent's strategy (coercive strategies), or else to set the ratio between the player's and their opponent's expected payoff (extortionate strategies). Here we show that zero-determinant strategies are at most weakly dominant, are not evolutionarily stable, and will instead evolve into less coercive strategies. We show that zero-determinant strategies with an informational advantage over other players that allows them to recognize each other can be evolutionarily stable (and able to exploit other players). However, such an advantage is bound to be short-lived as opposing strategies evolve to counteract the recognition.

Energy barrier analysis of Nd-Fe-B thin films

NASA Astrophysics Data System (ADS)

Goto, R.; Okamoto, S.; Kikuchi, N.; Kitakami, O.

2015-05-01

The magnetization reversal mechanism of a permanent magnet has long been a controversial issue, which is closely related to the so-called coercivity problem. It is well known that the energy barrier for magnetization reversal contains essential information on reversal process. In this study, we propose a method to analyze the energy barrier function for the magnetization reversal. Preferentially (001) oriented Nd-Fe-B films with and without a Nd overlayer are used as model magnets. By combining the magnetic viscosity and time dependent coercivity measurements, the barrier function has been successfully evaluated. As a result, although the Nd-Fe-B films with and without Nd overlayer exhibit different magnetic behaviors, the power indices for their energy barrier are almost the same, suggesting that the magnetization reversal proceeds in a similar mode.

Magnetization reversal and coercivity of Fe3Se4 nanowire arrays

NASA Astrophysics Data System (ADS)

Li, D.; Li, S. J.; Zhou, Y. T.; Bai, Y.; Zhu, Y. L.; Ren, W. J.; Long, G.; Zeng, H.; Zhang, Z. D.

2015-05-01

The microstructure and magnetic properties of Fe3Se4 nanowire (NW) arrays in anodic aluminum oxide (AAO) porous membrane are studied. Cross-sectional SEM and plane-view TEM images show that the mean wire diameter (dw) and the center-to-center spacing (D) of Fe3Se4 nanowires are about 220 nm and 330 nm, respectively. The field-cooled magnetization dependent on the temperature indicates a Curie temperature around 334 K for the Fe3Se4 nanowires. The coercivities of Fe3Se4 nanowires at 10 K, obtained from the in-plane and out-of-plane hysteresis loops, are as high as 22.4 kOe and 23.3 kOe, which can be understood from the magnetocrystalline anisotropy and the magnetization reversal process.

Structure and magnetic properties of Co2FeSi film deposited on Si/SiO2 substrate with Cr buffer layer

NASA Astrophysics Data System (ADS)

Chatterjee, Payel; Basumatary, Himalay; Raja, M. Manivel

2018-05-01

Co2FeSi thin films of 25 nm thickness with 50 nm thick Cr buffer layer was deposited on thermally oxidized Si substrates. Structural and magnetic properties of the films were studied as a function of annealing temperature and substrate temperatures. While the coercivity increases with increase in annealing temperature, it is found to decrease with increase in substrate temperature. A minimum coercivity of 18 Oe has been obtained for the film deposited at 550°C substrate temperature. This was attributed to the formation of L12 phase as observed from the GIXRD studies. The films with a good combination of soft magnetic properties and L21 crystal structure are suitable for spintronic applications.

A Simple Analytical Model for Magnetization and Coercivity of Hard/Soft Nanocomposite Magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Jihoon; Hong, Yang-Ki; Lee, Woncheol

Here, we present a simple analytical model to estimate the magnetization (σ s) and intrinsic coercivity (Hci) of a hard/soft nanocomposite magnet using the mass fraction. Previously proposed models are based on the volume fraction of the hard phase of the composite. But, it is difficult to measure the volume of the hard or soft phase material of a composite. We synthesized Sm 2Co 7/Fe-Co, MnAl/Fe-Co, MnBi/Fe-Co, and BaFe 12O 19/Fe-Co composites for characterization of their σs and Hci. The experimental results are in good agreement with the present model. Therefore, this analytical model can be extended to predict themore » maximum energy product (BH) max of hard/soft composite.« less

Microstructure Evolution and Related Magnetic Properties of Cu-Zr-Al-Gd Phase-Separating Metallic Glasses

NASA Astrophysics Data System (ADS)

Kim, Sang Jun; Kim, Jinwoo; Park, Eun Soo

2018-04-01

We carefully investigated the correlation between microstructures and magnetic properties of Cu-Zr-Al-Gd phase-separating metallic glasses (PSMGs). The saturation magnetizations of the PSMGs were determined by total Gd contents of the alloys, while their coercivity exhibits a large deviation by the occurrence of phase separation due to the boundary pinning effect of hierarchically separated amorphous phases. Especially, the PSMGs containing Gd-rich amorphous nanoparticles show the highest coercivity which can be attributed to the size effect of the ferromagnetic amorphous phase. Furthermore, the selective crystallization of ferromagnetic amorphous phases can affect the magnetization behavior of the PSMGs. Our results could provide a novel strategy for tailoring unique soft magnetic properties of metallic glasses by introducing hierarchically separated amorphous phases and controlling their crystallinity.

"Priority of liberty" and the design of a two-tier health care system.

PubMed

Breyer, Friedrich; Kliemt, Hartmut

2015-04-01

Libertarian views on rights tend to rule out coercive redistribution for purposes of public health care guarantees, whereas liberal conceptions support coercive funding of potentially unlimited access to medical services in the name of medical needs. Taking the "priority of liberty" seriously as supreme political value, a plausible prudential argument can avoid these extremes by providing systematic reasons for both delivering and limiting publicly financed guarantees. Given impending demographic change and rapid technical progress in medicine, only a two-tier system with explicitly limited public guarantees and optional privately financed health services seems acceptable. © The Author 2015. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Coercivity enhancement in Mn-Al-Cu flakes produced by surfactant-assisted milling

NASA Astrophysics Data System (ADS)

Saravanan, P.; Hsu, Jen-Hwa; Vinod, V. T. P.; Černík, Miroslav; Kamat, S. V.

2015-11-01

We herein report the achievement of exceptionally high coercivity (Hc) values: 9.92 and 5.86 kOe at 5 and 300 K, respectively, for Mn55Al43Cu2 flakes produced by surfactant-assisted milling process without employing any heat-treatment. The use of surfactants such as oleic acid and oleylamine during milling yielded high-aspect ratio flakes for the Mn-Al-Cu alloy. Structural studies confirmed the presence of τ- and β-phases as the major constituents in the Mn-Al-Cu flakes. The observed Hc enhancement is due to the increase in anisotropy field and structural defects, which is hypothesized to originate from the domain-wall pinning as a consequence of precipitation of fine Cu-particles present at the grain boundaries.

A Simple Analytical Model for Magnetization and Coercivity of Hard/Soft Nanocomposite Magnets

DOE PAGES

Park, Jihoon; Hong, Yang-Ki; Lee, Woncheol; ...

2017-07-10

Here, we present a simple analytical model to estimate the magnetization (σ s) and intrinsic coercivity (Hci) of a hard/soft nanocomposite magnet using the mass fraction. Previously proposed models are based on the volume fraction of the hard phase of the composite. But, it is difficult to measure the volume of the hard or soft phase material of a composite. We synthesized Sm 2Co 7/Fe-Co, MnAl/Fe-Co, MnBi/Fe-Co, and BaFe 12O 19/Fe-Co composites for characterization of their σs and Hci. The experimental results are in good agreement with the present model. Therefore, this analytical model can be extended to predict themore » maximum energy product (BH) max of hard/soft composite.« less

High discharge efficiency of (Sr, Pb, Bi) TiO3 relaxor ceramics for energy-storage application

NASA Astrophysics Data System (ADS)

Chao, Mingming; Liu, Jingsong; Zeng, Mengshi; Wang, Debin; Yu, Hongtao; Yuan, Ying; Zhang, Shuren

2018-05-01

We report herein on the energy storage and discharge properties of the relaxor ferroelectric ceramic Sr0.8Pb0.1Bi0.1TiO3 (SPBT). This material has a slanted hysteresis loop, and all samples show low remnant polarization and low coercive field, which leads to a high discharge efficiency. The maximum polarization is 10.1 μC/cm2, the minimum coercive field is 0.229 kV/cm, and the maximum efficiency is 94.2%. The discharge current waveforms are sinusoidal, the first discharge period is 140 ns, and the power density is approximately 4.2 × 107 W/kg. The high discharge speed and high discharge power density indicate that SPBT ceramics are very promising materials for energy storage applications.

Magnetic properties of carbon-coated, ferromagnetic nanoparticles produced by a carbon-arc method

NASA Astrophysics Data System (ADS)

Brunsman, E. M.; Sutton, R.; Bortz, E.; Kirkpatrick, S.; Midelfort, K.; Williams, J.; Smith, P.; McHenry, M. E.; Majetich, S. A.; Artman, J. O.; De Graef, M.; Staley, S. W.

1994-05-01

The Krätschmer-Huffman carbon-arc method of preparing fullerenes has been used to generate carbon-coated transition metal (TM) and TM-carbide nanocrystallites. The magnetic nanocrystallites were extracted from the soot with a magnetic gradient field technique. For TM=Co the majority of nanocrystals exist as nominally spherical particles, 0.5-5 nm in radius. Hysteretic and temperature-dependent magnetic response, in randomly and magnetically aligned powder samples frozen in epoxy, correspond to fine particle magnetism associated with monodomain TM particles. The magnetization exhibits a unique functional dependence on H/T, and hysteresis below a blocking temperature TB. Below TB, the temperature dependence of the coercivity can be expressed as Hc=Hc0[1-(T/TB)1/2], where Hc0 is the 0 K coercivity.

Microstructure Evolution and Related Magnetic Properties of Cu-Zr-Al-Gd Phase-Separating Metallic Glasses

NASA Astrophysics Data System (ADS)

Kim, Sang Jun; Kim, Jinwoo; Park, Eun Soo

2018-06-01

We carefully investigated the correlation between microstructures and magnetic properties of Cu-Zr-Al-Gd phase-separating metallic glasses (PSMGs). The saturation magnetizations of the PSMGs were determined by total Gd contents of the alloys, while their coercivity exhibits a large deviation by the occurrence of phase separation due to the boundary pinning effect of hierarchically separated amorphous phases. Especially, the PSMGs containing Gd-rich amorphous nanoparticles show the highest coercivity which can be attributed to the size effect of the ferromagnetic amorphous phase. Furthermore, the selective crystallization of ferromagnetic amorphous phases can affect the magnetization behavior of the PSMGs. Our results could provide a novel strategy for tailoring unique soft magnetic properties of metallic glasses by introducing hierarchically separated amorphous phases and controlling their crystallinity.

Multiferroic properties and frequency dependent coercive field in BiFeO3-LaMn0.5Co0.5O3 thin films

NASA Astrophysics Data System (ADS)

Lahmar, Abdelilah

2017-10-01

The effect of LaMn0.5Co0.5O3 (LMCO) adding on structural, magnetic, dielectric, and ferroelectric properties of BiFeO3 is presented. X ray diffraction and Raman investigation allowed the identification of a structural transition and permitted to shed more light on the influence of LCMO addition. By varying LMCO concentration, highest remnant polarization (Pr) and coercive field (Ec) with a likely square hysteresis loop are obtained for 10 mol% addition. With increasing concentration to 20 mol%, a change of P-E shape, a decrease of both Pr and Ec, and a frequency dependence of Ec are observed. The results are approached with both Ishibashi-Orihara and Du-Chen models.

Strong coercivity reduction and high initial permeability in NiCoP coated BaFe12O19-polystyrene bilayer composite

NASA Astrophysics Data System (ADS)

Hamad, Mahmoud A.; El-Sayed, Adly H.; Hemeda, O. M.; Tawfik, A.

2016-03-01

Soft-magnetic NiCoP coated hard-magnetic M-type ferrite BaFe12O19 (BaM)-polystyrene (PS) bilayer composite film was successfully synthesized. X-ray diffraction peaks exhibited no change in the structure of BaM after coating with PS. The NiCoP coated BaM-PS composite exhibited a wasp-waisted magnetic hysteretic loop with remarkable reduction in the coercivity, remanence and squareness with respect to BaM-PS, which is useful for the core of a magnetic switching device to control currents so large that they are unmanageable. Moreover, the initial permeability measurement exhibits initial permeability of around 100 000 and thermal stability up to 558 K, which is good for flux-amplifying components of smaller inductors.

Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magnetic shape memory effect

NASA Astrophysics Data System (ADS)

Heczko, O.; Drahokoupil, J.; Straka, L.

2015-05-01

Enhanced magnetic hysteresis due to boron doping in combination with magnetic shape memory effect in Ni-Mn-Ga single crystal results in new interesting functionality of magnetic shape memory (MSM) alloys such as mechanical demagnetization. In Ni50.0Mn28.5Ga21.5 single crystal, the boron doping increased magnetic coercivity from few Oe to 270 Oe while not affecting the transformation behavior and 10 M martensite structure. However, the magnetic field needed for MSM effect also increased in doped sample. The magnetic behavior is compared to undoped single crystal of similar composition. The evidence from the X-ray diffraction, magnetic domain structure, magnetization loops, and temperature evolution of the magnetic coercivity points out that the enhanced hysteresis is caused by stress-induced anisotropy.

Resistive and Ferroelectric-Domain Switching in Multiferroic BiFeO3 Films

NASA Astrophysics Data System (ADS)

Ramirez, J. G.; Arango, I. C.; Gomez, M. F.; Dominguez, C.; Sulekar, S.; Cardona, A.; Trastoy, J.; Nino, J. C.; Schuller, I. K.; Gomez, M. E.

Resistive switching (RS) in oxides has attracted much attention due to its potential application for nonvolatile memory and neuromorphic computing devices. Here we study the voltage-induced RS mechanisms in metal/multiferroic/semiconductor (Au/BiFeO3/Nb:SrTiO3) thin film vertical devices. We found switching with RON and ROFF ratios as big as 0.16 at voltages starting at +/- 2V. Further voltage increase produced an intensification of the RS effects, until dielectric breakdown was reached. Interestingly, the voltage at which the RS effect appears coincides with the coercive voltage of the ferroelectric polarization in similar BiFeO3 films, as measured by piezoelectric force microscopy. This suggests that the primary RS mechanism is the ferroelectric switching. Impedance spectroscopy measurements show filamentary contributions after ferroelectric saturation, possible due to voltage-induced movement of charge defects across the device and therefore suggesting an additional RS mechanism. Work supported by: Univalle CI 7999; FAPA at Uniandes; Colciencias 120471250659 and 120424054303. J.T. acknowledges the support from the Fundación Areces (Spain); AFOSR and DoD for a Vannevar Bush Fellowship.

Revisiting the False Confession Problem.

PubMed

Alvarez-Toro, Viviana; Lopez-Morales, Cesar A

2018-03-01

Despite the existence of important safeguards in our criminal legal system, innocent suspects often succumb to forceful and deceptive interrogation techniques. Among those over-represented members of the false confessor population are minors, people with cognitive and intellectual disabilities, and those with psychiatric disorders. Some of the confessions made by these at-risk populations can hardly be considered voluntary or reliable, but they are generally admitted at trial, regardless of their prejudicial effect. Forensic psychiatrists should become more involved in the overall process of evaluating confessions, not only testifying in courts, but also assisting policymakers in reforming the interrogation process and influencing the legal process. Thus, forensic psychiatrists may give their expert opinion by providing proper training to police interrogators and examining videotaped interrogations. In addition, forensic experts can be instrumental in contributing to three legal solutions that we propose to the false confession problem: a constitutional approach, an evidence law approach, and a jury instruction approach. Each of these approaches requires forensic psychiatrists to help judges and jurors understand the coercive nature of the interrogation process and its effect on suspects' behavior. © 2018 American Academy of Psychiatry and the Law.

Magnetic, local ferroelectricity and magnetodielectric properties of NiFe2O4-poly (vinylidene-fluoride)-BaTiO3 composite film

NASA Astrophysics Data System (ADS)

Kumar, Amit; Yadav, K. L.

2016-04-01

We report the magnetic, dielectric, and magnetoelctric properties of NiFe2O4-poly (vinylidene-fluoride)-BaTiO3 composite film. The coercive field (±2H c ˜ 344 Oe) and remnant magnetization (M r ˜ 6.1 emu g-1) were observed at room temperature. The dielectric permittivity at room temperature (ɛ‧RT ˜ 281) was found to decrease with increase in frequency. The magnetocapacitance was found to be ˜5.9% at an applied dc magnetic field of 8 kOe (frequency = 1 kHz). Magnetoelectric coupling coefficient (α E ˜ 4.1 mV cm-1 Oe-1) measured by dynamic method (at ac magnetic field = 30 Oe) is observed higher (two times) than those reported for some materials. In addition, we have observed the image of ferroelectric domain using piezoelectric force microscopy at room temperature. Large magnetodielectric/magnetoelectric response in this composite is possibly a result of the effective mechanical interaction between NiFe2O4 and BaTiO3 through the polymer matrix.

Thermoplastic deformation of ferromagnetic CoFe-based bulk metallic glasses

NASA Astrophysics Data System (ADS)

Wu, Chenguang; Hu, Renchao; Man, Qikui; Chang, Chuntao; Wang, Xinmin

2017-12-01

The superplastic deformation behavior of the ferromagnetic Co31Fe31Nb8B30 bulk metallic glass (BMG) in the supercooled liquid region was investigated. At a given temperature, the BMG exhibits a Newtonian behavior at low strain rates but a non-Newtonian behavior at high strain rates. The high thermal stability of this glassy alloy system offers an enough processing window to thermoplastic forming (TPF), and the strong processing ability was examined by simple micro-replication experiments. It is demonstrated that the TPF formability on length scales ranging down to nanometers can be achieved in the selected experimental condition. Based on the analysis of deformation behavior, the nearly full density sample (i.e. nearly 100%), was produced from water-atomized glassy powders and consolidated by the hot-pressing technique. The sample exhibits good soft-magnetic and mechanical properties, i.e., low coercive force of 0.43 Oe, high initial permeability of 4100 and high Vickers hardness 1398. These results suggest that the hot-pressing process opens up possibilities for the commercial exploitation of BMGs in engineering applications.

High-quality single-crystal thulium iron garnet films with perpendicular magnetic anisotropy by off-axis sputtering

NASA Astrophysics Data System (ADS)

Wu, C. N.; Tseng, C. C.; Lin, K. Y.; Cheng, C. K.; Yeh, S. L.; Fanchiang, Y. T.; Hong, M.; Kwo, J.

2018-05-01

High-quality single-crystal thulium iron garnet (TmIG) films of 10-30 nm thick were grown by off-axis sputtering at room temperature (RT) followed by post-annealing. X-ray photoelectron spectroscopy (XPS) was employed to determine the TmIG film composition to optimize the growth conditions, along with the aid of x-ray diffraction (XRD) structural analysis and atomic force microscope (AFM) for surface morphology. The optimized films exhibited perpendicular magnetic anisotropy (PMA) and the saturation magnetization at RT was ˜99 emu/cm3, close to the RT bulk value ˜110 emu/cm3 with a very low coercive field of ˜2.4 Oe. We extracted the H⊥ of 1734 Oe and the peak-to-peak linewidth ΔH of ferromagnetic resonance are only about 99 Oe, significantly lower than that of PLD grown TmIG film and bulk single crystals. The high-quality sputtered single-crystal TmIG films show great potential to be integrated with topological insulators or heavy metals with strong spin-orbit coupling for spintronic applications.

A 3D-Printable Polymer-Metal Soft-Magnetic Functional Composite-Development and Characterization.

PubMed

Khatri, Bilal; Lappe, Karl; Noetzel, Dorit; Pursche, Kilian; Hanemann, Thomas

2018-01-25

In this work, a 3D printed polymer-metal soft-magnetic composite was developed and characterized for its material, structural, and functional properties. The material comprises acrylonitrile butadiene styrene (ABS) as the polymer matrix, with up to 40 vol. % stainless steel micropowder as the filler. The composites were rheologically analyzed and 3D printed into tensile and flexural test specimens using a commercial desktop 3D printer. Mechanical characterization revealed a linearly decreasing trend of the ultimate tensile strength (UTS) and a sharp decrease in Young's modulus with increasing filler content. Four-point bending analysis showed a decrease of up to 70% in the flexural strength of the composite and up to a two-factor increase in the secant modulus of elasticity. Magnetic hysteresis characterization revealed retentivities of up to 15.6 mT and coercive forces of up to 4.31 kA/m at an applied magnetic field of 485 kA/m. The composite shows promise as a material for the additive manufacturing of passive magnetic sensors and/or actuators.

A 3D-Printable Polymer-Metal Soft-Magnetic Functional Composite—Development and Characterization

PubMed Central

Lappe, Karl; Noetzel, Dorit; Pursche, Kilian; Hanemann, Thomas

2018-01-01

In this work, a 3D printed polymer–metal soft-magnetic composite was developed and characterized for its material, structural, and functional properties. The material comprises acrylonitrile butadiene styrene (ABS) as the polymer matrix, with up to 40 vol. % stainless steel micropowder as the filler. The composites were rheologically analyzed and 3D printed into tensile and flexural test specimens using a commercial desktop 3D printer. Mechanical characterization revealed a linearly decreasing trend of the ultimate tensile strength (UTS) and a sharp decrease in Young’s modulus with increasing filler content. Four-point bending analysis showed a decrease of up to 70% in the flexural strength of the composite and up to a two-factor increase in the secant modulus of elasticity. Magnetic hysteresis characterization revealed retentivities of up to 15.6 mT and coercive forces of up to 4.31 kA/m at an applied magnetic field of 485 kA/m. The composite shows promise as a material for the additive manufacturing of passive magnetic sensors and/or actuators. PMID:29370112

Magnetic properties and transmission electron microscopy studies of Ni nanoparticles encapsulated in carbon nanocages and carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

He Chunnian; Zhao Naiqin; Shi Chunsheng

2008-08-04

Three types of carbon nanomaterials, including bamboo-shaped carbon nanotubes with Ni encapsulated and hollow and Ni catalytic particles filled carbon nanocages, have been prepared by methane catalytic decomposition at a relatively low temperature. Transmission electron microscopy observations showed that fascinating fullerene-like Ni-C (graphitic) core-shell nanostructures predominated. Detailed examination of high-resolution transmission electron microscopy showed that the walls of bamboo-shaped carbon nanotubes with quasi-cone catalytic particles encapsulated consisted of oblique graphene planes with respect to the tube axis. The Ni particles encapsulated in the carbon nanocages were larger than that encapsulated in carbon nanotubes, but the diameters of the cores ofmore » hollow carbon nanocages were less than that of Ni particles encapsulated in carbon nanotubes, suggesting that the sizes of catalyst particles played an important role during carbon nanomaterial growth. The magnetic properties of the carbon nanomaterials were measured, which showed relatively large coercive force (H{sub c} = 138.4 O{sub e}) and good ferromagnetism (M{sub r}/M{sub s} = 0.325)« less

Change in the magnetic properties of nanoferrihydrite with an increase in the volume of nanoparticles during low-temperature annealing

NASA Astrophysics Data System (ADS)

Balaev, D. A.; Krasikov, A. A.; Stolyar, S. V.; Iskhakov, R. S.; Ladygina, V. P.; Yaroslavtsev, R. N.; Bayukov, O. A.; Vorotynov, A. M.; Volochaev, M. N.; Dubrovskiy, A. A.

2016-09-01

The results of the investigation into the effect of low-temperature annealing of a powder of nanoparticles of bacterial ferrihydrite on its magnetic properties have been presented. It has been found that an increase in the time (up to 240 h) and temperature (in the range from 150 to 200°C) of annealing leads to a monotonic increase in the superparamagnetic blocking temperature, the coercive force, and the threshold field of the opening of the magnetic hysteresis loop (at liquid-helium temperatures), as well as to an increase in the magnetic resonance line width at low temperatures and in the magnetic susceptibility at room temperature. At the same time, according to the results of the analysis of the Mössbauer spectra, the annealing of ferrihydrite does not lead to the formation of new iron oxide phases. Most of these features are well consistent with the fact that the low-temperature annealing of ferrihydrite causes an increase in the size of nanoparticles, which is confirmed by the results of transmission electron microscopy studies.

The influence of parenting style on health related behavior of children: findings from the ChiBS study

PubMed Central

2014-01-01

Objective Exploring associations between parenting behavior and children’s health related behavior including physical activity, sedentary behavior, diet and sleep. Methods We recruited 288 parents and their children (6-12y old). Children’s weight and height were measured. Fat percentage was determined by air displacement plethysmography. Parents reported socio-demographic data, sleep information, physical activity and sedentary behavior of their child and completed the Comprehensive General Parenting Questionnaire (CGPQ) and a Food Frequency Questionnaire. Children completed the Dutch Eating Behavior Questionnaire. Associations between parenting behavior (CGPQ) and children’s health related behavior were assessed with univariate and multiple regression analyses. Results A small positive correlation was found between sweet food consumption frequency and “coercive control” (r = 0.139) and a small negative correlation between fruit and vegetables consumption frequency and “overprotection” (r = −0.151). Children consumed more frequently soft drinks when their parents scored lower on “structure” (r = −0.124) and higher on “overprotection” (r = 0.123); for the light soft drinks separately, a small positive correlation with “behavioral control” was found (r = 0.172). A small negative correlation was found between “emotional eating” and “structure” (r = −0.172) as well as “behavioral control” (r = −0.166). “Coercive control” was negatively correlated with the child’s sleep duration (r = −0.171). After correction for confounding factors, the following significant associations were found: (1) a small negative association between “structure” and soft drinks consumption (β = −0.17 for all soft drinks and −0.22 for light soft drinks), (2) a small positive association between “behavioral control” and light soft drinks (β = 0.34), (3) a small positive association of “nurturance” and “coercive control” with sedentary behavior (β = 0.16 for both parent constructs) and (4) a small negative association between the parenting construct “coercive control” and sleep duration (β = −0.23). Conclusion The significant but small associations between parenting constructs and the investigated variables suggest that different aspects of parenting style play an important role in the genesis of the health related behavior of children. Overall, our findings suggest that health professionals should encourage parents to apply the more positive parenting constructs i.e., more “structure” and “behavioral control”, and less “coercive control”. They could, for instance, supervise and manage their child’s activities and help their child to achieve certain goals. PMID:25052905

Rock Magnetic Fabrics, Paleomagnetic Vectors, and Rock Magnetic Cyclostratigraphy of the Marcellus FM, Sunbury PA

NASA Astrophysics Data System (ADS)

Minguez, D. A.; Kodama, K. P.

2013-12-01

We present the preliminary results of a multi-faceted rock magnetic study conducted on 195 samples from the Oatka Creek member of the Marcellus formation, where it has been extracted from the subsurface as a drill core near Sunbury, PA. Samples were oriented based on bedding attitude observed within the core and were removed from the core at a spacing of ≈0.25 meters starting from the base (depth ≈ 500 meters) and spanning 51 meters of stratigraphic section. The results of measurements of the anisotropy of magnetic susceptibility (AMS) consistently demonstrate a nearly triaxial fabric with maximum principal axes clustering east-west and horizontal in geographic coordinates, nearly parallel to the direction of bedding strike. AMS minimum principal axes cluster near the pole to the bedding plane. Anisotropy of anhysteretic remanence (AAR) applied with a 100 mT peak field and a 97 μT bias field in 9 orientations demonstrates a markedly different fabric, with maximum principal axis clustering north-south and horizontal in geographic coordinates. Minimum principal axes of AAR cluster steeply (~60-70 degrees) to the west. The discrepancy between AAR and AMS fabrics likely indicates the AMS is dominated by paramagnetic clays, and thus may be interpreted as an east-west intersection lineation of clay particles dipping gently north or south. Paleomagnetic directions obtained using Alternating Field (AF) demagnetization in 5 mT steps up to 110 mT demonstrates a high coercivity remanence (>35 mT) with a south and shallow direction (D= 183.4 I=-14.7). This result is consistent with previous studies of the Marcellus formation and the Devonian Catskill red beds. Thermal demagnetization experiments demonstrate a similar magnetization removed by temperatures between 250 and 350 degrees Celsius, however, continued heating results in the acquisition of strong, inconsistent magnetizations likely the result of oxidizing iron sulfides. Thermal demagnetization of orthogonal partial ARMs applied in 100 mT and 50 mT peak fields was conducted on a subset of samples sealed in aluminum foil with alumina-silica cement to prevent oxidization. The results demonstrate that the low coercivity pARM is removed by 400 degrees Celsius and the high coercivity pARM, which is only 10% of the total remanence, is removed by 600 degrees Celsius. The results suggest the presence of low coercivity Fe sulfides and high coercivity magnetite. Lastly, time series analysis of bulk magnetic susceptibility using the Multi-Taper Method (MTM) demonstrates oscillations with a wavelength of 18 meters above the 99% confidence level with respect to the robust red noise. This wavelength may have a duration of 405 kyr given ancillary chronostratigraphic evidence.

Cyberpower as a Coercive Instrument

DTIC Science & Technology

2009-06-01

weaknesses. Members 10 Lech Janczewski and Andrew M. Colarik, Cyber Warfare and Cyber Terrorism, (Idea...Polity Press, 2004. 66 Freedman, Lawrence. Strategic Coercion: Concepts and Cases, Oxford: Oxford University Press, 1998. Janczewski, Lech

Paleomagnetic and Rock Magnetic Study of Oligocene-Holocene Sedimentary Rocks from Northern Dominican Republic: Evidence of Vertical Axis Rotations

NASA Astrophysics Data System (ADS)

Anson Sanchez, M.; Kodama, K. P.; Pueyo, E. L.; Soto, R.; Garcia-Senz, J.; Escuder-Viruete, J.; Pastor-Galan, D.

2017-12-01

A paleomagnetic and rock magnetic study was conducted in the northern Dominican Republic to detect vertical axis rotations in an active left-lateral, strike slip fault zone. 191 samples from 21 sites were collected from a variety of lithologies including limestones, conglomerates, calcarenites and marls that ranged in age from the Oligocene to the Holocene. The rock magnetic portion of the study focused on the identification of magnetic minerals using coercivity, and Curie temperature (c vs temperature) measurement, modeling of IRM acquisition curves, and thermal demagnetization of IRMs (Lowrie, 19901). In the paleomagnetic portion of the study characteristic remanences (ChRMs) were isolated using thermal demagnetization (19 steps up to 680ºC) and alternating field (AF) demagnetization (17 steps up to 100 mT). In most cases the characteristic remanence is carried by magnetite, with peak unblocking temperatures of 575ºC. This interpretation was supported by c vs. T results that yielded Curie temperatures of 580˚C. In only a few cases (7 samples) higher unblocking temperatures suggested hematite as the magnetic carrier. The modeling of IRM acquisition curves, that shows two coercivity components, further supports the presence of magnetite. 75% of the IRM is carried by the low-coercivity component (100-300 mT, magnetite). 25% of the IRM is carried by the high-coercivity component (1.2-1.6T) characteristic of hematite. The IRM acquisition data was collected from 24 samples (3-4 from each of the lithologies sampled). IRMs were acquired in fields from 4mT to 1T in 23 steps. The paleomagnetic results show a grouping by tectonic blocks with one group having westerly ChRM declinations (268˚-295˚) and a second group having northerly ChRM declinations (357˚-035˚). In most cases, inclinations are intermediate ( 35˚), in agreement with the 24˚-31˚ expected inclinations for Dominican Republic in the period Oligocene to Holocene. The rotation of the tectonic blocks, as detected by the declinations, is consistent with a left-lateral strike-slip motion across the main fault in the area. 1Lowrie, 1990, GRL, 17, 159-162

Multi-scale characterization by FIB-SEM/TEM/3DAP.

PubMed

Ohkubo, T; Sepehri-Amin, H; Sasaki, T T; Hono, K

2014-11-01

In order to improve properties of functional materials, it is important to understand the relation between the structure and the properties since the structure has large effect to the properties. This can be done by using multi-scale microstructure analysis from macro-scale to nano and atomic scale. Scanning electron microscope (SEM) equipped with focused ion beam (FIB), transmission electron microscope (TEM) and 3D atom probe (3DAP) are complementary analysis tools making it possible to know the structure and the chemistry from micron to atomic resolution. SEM gives us overall microstructural and chemical information by various kinds of detectors such as secondary electron, backscattered electron, EDS and EBSD detectors. Also, it is possible to analyze 3D structure and chemistry via FIB serial sectioning. In addition, using TEM we can focus on desired region to get more complementary information from HRTEM/STEM/Lorentz images, SAED/NBD patterns and EDS/EELS to see the detail micro or nano-structure and chemistry. Especially, combination of probe Cs corrector and split EDS detectors with large detector size enable us to analyze the atomic scale elemental distribution. Furthermore, if the specimen has a complicated 3D nanostructure, or we need to analyze light elements such as hydrogen, lithium or boron, 3DAP can be used as the only technique which can visualize and analyze distribution of all constituent atoms of our materials within a few hundreds nm area. Hence, site-specific sample preparation using FIB/SEM is necessary to get desired information from region of interest. Therefore, this complementary analysis combination works very well to understand the detail of materials.In this presentation, we will show the analysis results obtained from some of functional materials by Carl Zeiss CrossBeam 1540EsB FIB/SEM, FEI Tecnai G(2) F30, Titan G2 80-200 TEMs and locally build laser assisted 3DAP. As the one of the example, result of multi-scale characterization for ultra-fine grain Nd-Fe-B permanent magnet will be shown [1]. In order to improve the magnetic properties, especially to increase the coercivity (resistance against magnetization reversal) of the magnet, decreasing the grain size and isolating each grain by non-ferromagnetic grain boundary phase are quite important since the nucleation of magnetic reversal from grain boundary phase can be suppressed and pinning force of magnetic domain wall at the grain boundary phase can be strengthened. Therefore, micro and nano structure and chemistry analysis can shed a light do grain boundary engineering.Figure 1(a,b) shows SEM BSE images of ultrafine grain Nd-Fe-B sintered magnet and the reconstructed 3D tomography of Nd-rich phases obtained by FIB/SEM serial sectioning. This data can provide us information about the distribution of Nd-rich phase and its volume fraction. Moreover, the HRTEM image from the grain boundary phase, the 3DAP maps and the concentration depth profiles are shown in Fig. 1(c,d,e). This magnet shows high coercivity (1517kA/m), and by comparing these results with the microstructures of low coercivity specimen, importance of grain boundary formation was confirmed and it gives us hint to improve the coercivity further. We will show the detail and results from other materials.jmicro;63/suppl_1/i6/DFU046F1F1DFU046F1Fig. 1.(a) SEM BSE images of ultrafine grain Nd-Fe-B sintered magnet. (b) 3D FIB/SEM tomography of Nd-rich phases. (c) HRTEM image from the grain boundary phase. (d) 3DAP maps of Nd, Cu and Al. (e) Concentration depth profiles for Fe, Nd+Pr, B, Co, Cu and Al, determined from the selected box in (d)[1]. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Rock magnetic properties of dusty olivine: a potential carrier of pre-accretionary remanence in unequilibrated ordinary chondrites

NASA Astrophysics Data System (ADS)

Lappe, S. C. L. L.; Harrison, R. J.; Feinberg, J. M.

2012-04-01

The mechanism of chondrule formation is an important outstanding question in cosmochemistry. Magnetic signals recorded by Fe-Ni nanoparticles in chondrules could carry clues to their origin. Recently, research in this area has focused on 'dusty olivine' grains within ordinary chondrites as potential carriers of pre-accretionary remanence. Dusty olivine is characterised by the presence of sub-micron Fe-Ni inclusions within the olivine host. These metal particles form via subsolidus reduction of the olivine during chondrule formation and are thought to be protected from subsequent chemical and thermal alteration by the host olivine. Three sets of synthetic dusty olivines have been produced, using natural olivine (average Ni-content of 0.3 wt%), synthetic Ni-containing olivine (0.1wt% Ni) and synthetic Ni-free olivine as starting materials. The starting materials were ground to powders, packed into a 2-3 mm3 graphite crucible, heated up to 1350 °C under a pure CO gas flow and kept at this temperature for 10 minutes. After this the samples were held in a fixed orientation and quenched into water in a range of known magnetic fields, ranging from 0.2 mT to 1.5 mT. We present here for the first time an analysis of a new FORC-based method of paleointensity determination applied to metallic Fe-bearing samples [1, 2]. The method uses a first-order reversal curve (FORC) diagram to generate a Preisach distribution of coercivities and interaction fields within the sample and then physically models the acquisition of TRM as a function of magnetic field, temperature and time using thermal relaxation theory. The comparison of observed and calculated NRM demagnetisation spectra is adversely effected by a large population of particles in the single-vortex state. Comparison of observed and calculated REM' curves, however, yields much closer agreement in the high-coercivity SD-dominated range. Calculated values of the average REM' ratio show excellent agreement with the experimental values - including the observed non-linearity of the remanence acquisition curve - suggesting that this method has the potential to reduce the uncertainties in non-heating paleointensity methods for extraterrestrial samples. [1] AR Muxworthy and D Heslop(2011) A Preisach method for estimating absolute paleofield intensity under the constraint of using only isothermal measurements: 1. Theoretical framework. Journal of Geophysical Research, 116, B04102, doi:10.1029/2010JB007843. [2] AR Muxworthy, D Heslop, GA Paterson, and D Michalk. A Preisach method for estimating absolute paleofield intensity under the constraint of using only isothermal measurements: 2. Experimental testing. Journal of Geophysical Research, 116, B04103, doi:10.1029/2010JB007844.

Coercive Power of the Federal Purse

ERIC Educational Resources Information Center

Brewster, Kingman

1975-01-01

Cites examples of use of the leverage of the government dollar to manipulate for vindictive or political purposes. Examples include the proposed health manpower legislation and the Family Educational Rights and Privacy Act. (GS)

Exchange bias induced by the fully strained La{sub 2/3}Ca{sub 1/3}MnO{sub 3} dead layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Q. Y.; College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210046; Wu, X. S., E-mail: xswu@nju.edu.cn

A pure compressively strained La{sub 2/3}Ca{sub 1/3}MnO{sub 3} (LCMO) dead layer grown on (001)-oriented LaAlO{sub 3} substrate can show all the rich phenomenon of large bias field shift, coercive field enhancement, and high blocking temperature. The obtained exchange bias field (∼350 Oe) and the enhanced coercivity of about 1160 Oe at 5 K under 500 Oe cooling field are superior to that have been reported in LCMO-based ferromagnetic/antiferromagnetic superlattices or nanoscale systems. Our results clearly demonstrate that the inhomogeneous magnetic dead layer of LCMO can induce a strong exchange bias effect, which may be exploited as a very simple structure for spin-valve device application.

Obstetricians and violence against women.

PubMed

Charles, Sonya

2011-12-01

I argue that the American Congress of Obstetricians and Gynecologists (ACOG), as an organization and through its individual members, can and should be a far greater ally in the prevention of violence against women. Specifically, I argue that we need to pay attention to obstetrical practices that inadvertently contribute to the problem of violence against women. While intimate partner violence is a complex phenomenon, I focus on the coercive control of women and adherence to oppressive gender norms. Using physician response to alcohol use during pregnancy and court-ordered medical treatment as examples, I show how some obstetrical practices mirror the attitudes of abusive men insofar as they try to coercively control women's behavior through manipulation and violence. To be greater allies in the prevention of violence against women, obstetricians should stop participating in practices that inadvertently perpetuate violence against women.

How Power Mechanism Influence Channel Bilateral Opportunism

NASA Astrophysics Data System (ADS)

Tian, Yu; Chen, Shaodan

In the background of marketing channel power asymmetry structure, this article discuss the relation between power dominant member’s use of power mechanism and the opportunism behavior of both Power disadvantage member and the power dominant member itself, and test whether distributive fairness perception and procedural fairness perception have moderate effects on this relation. The result shows that, the power dominant member’s use of coercive power will increase the opportunistic tendency of both sides; in contrast, the power dominant member’s use of noncorecive power will inhibit such tendency. Distributive fairness perception and procedural fairness perception negatively moderate the relation between power dominant member’s use of noncorecive power and power disadvantage member’s opportunism. Procedural fairness perception also negatively moderates the relation between power dominant member’s use of coercive power and the other side’s opportunism.

A rock-magnetic record from Lake Baikal, Siberia: Evidence for Late Quaternary climate change

USGS Publications Warehouse

Peck, J.A.; King, J.W.; Colman, Steven M.; Kravchinsky, V.A.

1994-01-01

Rock-magnetic measurements of sediment cores from the Academician Ridge region of Lake Baikal, Siberia show variations related to Late Quaternary climate change. Based upon the well-dated last glacial-interglacial transition, variations in magnetic concentration and mineralogy are related to glacial-interglacial cycles using a conceptual model. Interglacial intervals are characterized by low magnetic concentrations and a composition that is dominated by low coercivity minerals. Glacial intervals are characterized by high magnetic concentrations and increased amounts of high coercivity minerals. The variation in magnetic concentration is consistent with dilution by diatom opal during the more productive interglacial periods. We also infer an increased contribution of eolian sediment during the colder, windier, and more arid glacial conditions when extensive loess deposits were formed throughout Europe and Asia. Eolian transport is inferred to deliver increased amounts of high coercivity minerals as staining on eolian grains during the glacial intervals. Variations in magnetic concentration and mineralogy of Lake Baikal sediment correlate to the SPECMAP marine oxygen-isotope record. The high degree of correlation between Baikal magnetic concentration/mineralogy and the SPECMAP oxygen-isotope record indicates that Lake Baikal sediment preserves a history of climate change in central Asia for the last 250 ka. This correlation provides a method of estimating the age of sediment beyond the range of the radiocarbon method. Future work must include providing better age control and additional climate proxy data, thereby strengthening the correlation of continental and marine climate records. ?? 1994.

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co90Fe10 bilayers

NASA Astrophysics Data System (ADS)

Zheng, Chao; Su, Shan; Chiu, Chun-Cheng; Skoropata, Elizabeth; Desautels, Ryan D.; van Lierop, Johan; Lin, Ko-Wei; Pong, Philip W. T.

2018-01-01

The ferromagnetic (FM)/antiferromagnetic (AF) bilayer structures have drawn intensive attention because of their wide applications in modern spintronic devices. While abundant published works have been reported on the interface effects of the FM/AF bilayers caused by the magnetic field annealing (MFA) process, the volume effects caused by the MFA treatment have been rarely considered. In this work, the microstructural and magnetic properties of the NiO/CoFe bilayers with various CoFe thicknesses were investigated under different annealing temperatures. At high annealing temperature, the interlayer mixing and exchange coupling between NiO and CoFe layers were promoted and consequently the interface effects were facilitated. The interfacial oxides acted as pinning centers and randomly pinned the FM domains, leading to an increase of coercivity and a considerable degradation of uniaxial anisotropy. The increase of coercivity was also contributed by the enhancement of the interfacial exchange coupling between the NiO and CoFe layers after MFA. As the CoFe thickness increased, the volume effects tended to dominate over the interface effects, resulting in the preservation the uniaxially anisotropic features of CoFe. These results indicate that both the coercivity and anisotropic features of the NiO/CoFe bilayers can be directly affected by the MFA process, opening up the possibility of modifying the magnetism in the NiO/CoFe bilayers and offering an effective way to improve the performance of modern spintronic devices.

Enhancing Tax Compliance through Coercive and Legitimate Power of Tax Authorities by Concurrently Diminishing or Facilitating Trust in Tax Authorities.

PubMed

Hofmann, Eva; Gangl, Katharina; Kirchler, Erich; Stark, Jennifer

2014-07-01

Both coercion, such as strict auditing and the use of fines, and legitimate procedures, such as assistance by tax authorities, are often discussed as means of enhancing tax compliance. However, the psychological mechanisms that determine the effectiveness of each strategy are not clear. Although highly relevant, there is rare empirical literature examining the effects of both strategies applied in combination. It is assumed that coercion decreases implicit trust in tax authorities, leading to the perception of a hostile antagonistic tax climate and enforced tax compliance. Conversely, it is suggested that legitimate power increases reason-based trust in the tax authorities, leading to the perception of a service climate and eventually to voluntary cooperation. The combination of both strategies is assumed to cause greater levels of intended compliance than each strategy alone. We conducted two experimental studies with convenience samples of 261 taxpayers overall. The studies describe tax authorities as having low or high coercive power (e.g., imposing lenient or severe sanctions) and/or low or high legitimate power (e.g., having nontransparent or transparent procedures). Data analyses provide supportive evidence for the assumptions regarding the impact on intended tax compliance. Coercive power did not reduce implicit trust in tax authorities; however, it had an effect on reason-based trust, interaction climate, and intended tax compliance if applied solely. When wielded in combination with legitimate power, it had no effect.

Effect of Nb doping on the microstructure and magnetic properties of Nd-Ce-Fe-B alloy

NASA Astrophysics Data System (ADS)

Quan, Qichen; Zhang, Lili; Jiang, Qingzheng; Lei, Weikai; Zeng, Qingwen; Hu, Xianjun; Wang, Lei; Yu, Xi; Du, Junfeng; Fu, Gang; Liu, Renhui; Zhong, Minglong; Zhong, Zhenchen

2017-11-01

With the intention to reduce the Nd content in Nd2Fe14B-type alloys, 20 at.% Ce and 0.5 at.% Nb substituting Nd and Fe in the Nd13Fe82B5 alloys were previously employed to improve successfully the coercivity and the thermal stability without the energy product reduction. In this study, a light increase of the remnant polarization Jr was observed in (Nd0.8Ce0.2)13Fe82-xNbxB5 alloy at x = 0.5 and x = 1.0, resulting from the increasing amount of α-Fe phase. The optimum magnetic properties obtained with 0.5 at.% Nb doping are Hcj = 13.1 kOe, Jr = 0.79 T, (BH)max = 13.3 MGOe, respectively. Besides, the coercivity Hcj and maximum energy product (BH)max for the melt-spun ribbons with 0.5 at.% Nb addition are higher than those of the Nb-free ribbons in the temperature range of 300-450 K. Both the variations of Curie temperature Tc and a increase of lattice constants a and c of the hard magnetic phase with Nb addition imply that some of Nb atoms may directly enter into the hard magnetic phase, occupying the Fe sites. With the analysis on the demagnetization curve, Henkel curve and the observation of transmission electron microscope (TEM), the results indicate that a small amount of Nb can enhance the coercivity and exchange coupling though improving the microstructure of alloys.

Artificial multiferroic structures using soft magnetostrictive bilayers on Pb(Mg1/3Nb2/3)-PbTiO3

NASA Astrophysics Data System (ADS)

Miskevich, E.; Alshammari, F. K.; Yang, W.-G.; Sharp, J.; Baco, S.; Leong, Z.; Abbas, Q. A.; Morley, N. A.

2018-02-01

Artificial multiferroic structures are of great interest as they combine two or more functionalities together. One example of these structures is magnetostrictive films grown on top of piezoelectric substrates; allowing the magnetisation hysteresis loop of the magnetostrictive film to be manipulated using an electric field across the structure rather than a magnetic field. In this paper, we have studied the multiferroic structure NiFe/FeCo/Ti/Pb(Mg1/3Nb2/3)-PbTiO3 (PMN-PT) as a function of the electric and magnetic field. Soft magnetostrictive bilayer films (NiFe/FeCo) are studied, as often applications require soft magnetic properties (small coercive and anisotropy fields) combined with larger magnetostrictive constants. Unfortunately, FeCo films can have coercive fields that are too large, while NiFe films’ magnetostriction constants are almost zero; thus, combining the two together should produce the ‘ideal’ soft magnetostrictive film. It was found that the addition of a thin NiFe film onto the FeCo film reduced the coercive field and remnant magnetisation on the application of an applied voltage in comparison to just the FeCo film. It was also determined that for the NiFe/FeCo bilayer the magnetisation switchability was ~100% on the application of 8 kV cm-m, which was higher than the monolayer FeCo films at the same applied field, demonstrating improvement of the multiferroic behaviour by the soft magnetic/magnetostrictive bilayer.

Magnetization reversal of in-plane uniaxial Co films and its dependence on epitaxial alignment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Idigoras, O., E-mail: o.idigoras@nanogune.eu; Suszka, A. K.; Berger, A.

2014-02-28

This work studies the influence of crystallographic alignment onto magnetization reversal in partially epitaxial Co films. A reproducible growth sequence was devised that allows for the continuous tuning of grain orientation disorder in Co films with uniaxial in-plane anisotropy by the controlled partial suppression of epitaxy. While all stable or meta-stable magnetization states occurring during a magnetic field cycle exhibit a uniform magnetization for fully epitaxial samples, non-uniform states appear for samples with sufficiently high grain orientation disorder. Simultaneously with the occurrence of stable domain states during the magnetization reversal, we observe a qualitative change of the applied field anglemore » dependence of the coercive field. Upon increasing the grain orientation disorder, we observe a disappearance of transient domain wall propagation as the dominating reversal process, which is characterized by an increase of the coercive field for applied field angles away from the easy axis for well-ordered epitaxial samples. Upon reaching a certain disorder threshold level, we also find an anomalous magnetization reversal, which is characterized by a non-monotonic behavior of the remanent magnetization and coercive field as a function of the applied field angle in the vicinity of the nominal hard axis. This anomaly is a collective reversal mode that is caused by disorder-induced frustration and it can be qualitatively and even quantitatively explained by means of a two Stoner-Wohlfarth particle model. Its predictions are furthermore corroborated by Kerr microscopy and by Brillouin light scattering measurements.« less

Textured Nd2Fe14B flakes with enhanced coercivity

NASA Astrophysics Data System (ADS)

Cui, B. Z.; Zheng, L. Y.; Marinescu, M.; Liu, J. F.; Hadjipanayis, G. C.

2012-04-01

Morphology, structure, and magnetic properties of the [001] textured Nd2Fe14B nanocrystalline flakes prepared by surfactant-assisted high energy ball milling (HEBM) and subsequent annealing were studied. These flakes have a thickness of 80-200 nm, a length of 0.5-10 μm, and an average grain size of 10-14 nm. The addition of some amount of Dy, Nd70Cu30 alloy, and an appropriate post annealing increased the coercivity iHc of the Nd2Fe14B flakes. iHc was 3.7, 4.3, and 5.7 kOe for the Nd15.5Fe78.5B6, Nd14Dy1.5Fe78.5B6 and 83.3 wt.% Nd14Dy1.5Fe78.5B6 + 16.7 wt.% Nd70Cu30 flakes prepared by HEBM for 5 h in heptane with 20 wt.% oleylamine, respectively. After annealing at 450 °C for 0.5 h, their iHc increased to 5.1, 6.2, and 7.0 kOe, respectively. Anisotropic magnetic behavior was found in all of the as-milled and annealed flakes. Both, the thickening of Nd-rich phase at grain boundaries via diffusion of Nd70Cu30 and the surface modification of the Nd2Fe14B flake could be the main reasons for the coercivity enhancement in the as-milled and annealed Nd70Cu30-added Nd2Fe14B flakes.

Coercive Family Process and Early-Onset Conduct Problems From Age 2 to School Entry

PubMed Central

Smith, Justin D.; Dishion, Thomas J.; Shaw, Daniel S.; Wilson, Melvin N.; Winter, Charlotte C.; Patterson, Gerald R.

2013-01-01

The emergence and persistence of conduct problems during early childhood is a robust predictor of behavior problems in school and future maladaptation. In this study we examined the reciprocal influences between observed coercive interactions between children and caregivers, oppositional and aggressive behavior, and growth in parent report of early childhood (ages 2–5) and school-age conduct problems (age 7.5 and 8.5). Participants were drawn from the Early Steps multisite randomized prevention trial that includes an ethnically diverse sample of male and female children and their families (N = 731). A parallel process growth model combining latent trajectory and cross-lagged approaches revealed the amplifying effect of observed coercive caregiver–child interactions on children's noncompliance, whereas child oppositional and aggressive behaviors did not consistently predict increased coercion. The slope and initial levels of child oppositional and aggressive behaviors and the stability of caregiver–child coercion were predictive of teacher-reported oppositional behavior at school age. Families assigned to the Family Check-Up condition had significantly steeper declines in child oppositional and aggressive behavior and moderate reductions in oppositional behavior in school and in coercion at age 3. Results were not moderated by child gender, race/ethnicity, or assignment to the intervention condition. The implications of these findings are discussed with respect to understanding the early development of conduct problems and to designing optimal strategies for reducing problem behavior in early childhood with families most in need. PMID:24690305

Reproduced multi-domain regions during demagnetization in Nd2Fe14B sintered magnets with different average grain sizes

NASA Astrophysics Data System (ADS)

Kobayashi, Kurima; Nimura, You-ta; Urushibata, Kimiko; Hayakawa, Kazuo

2018-04-01

We prepared five Nd2Fe14B sintered magnets with similar saturation polarizations (Js) of 1.38-1.43 T and anisotropy fields (Ha) of 6.76-8.52 T, but different grain sizes (DAV) of 3.1-8.4 μm in diameter and obviously different coercivities (μ0Hc) of 0.8-1.6 T. The observed difference in coercivity could not be explained by the Kronmüller equation, because of the similar Ha values and similar chemical compositions and microstructures resulting from similar preparation method except DAV. The Hc values themselves, however, are inversely proportional to DAV. During demagnetization after magnetization in a 5 T pulse field, domain wall motion (DWM) was observed except in the sample with μ0Hc = 1.6 T by using our step method. The DWM was also confirmed by susceptibility measurements using a custom-built vibrating sample magnetometer, and DWM was generated in the reproduced multi-domain regions (RMDR) during demagnetization. The magnitude of DWM as a polarization change in the RMDR was inversely proportional to the coercivities of the samples. Therefore, it should be considered that the propagation of the nucleated region through the grain boundary, which corresponds to the expansion process in previous studies, was different caused by, first, the difference in DAV, and, second, in grain boundary state which was varied by difference in final annealing temperature.

Enhancing Tax Compliance through Coercive and Legitimate Power of Tax Authorities by Concurrently Diminishing or Facilitating Trust in Tax Authorities

PubMed Central

Hofmann, Eva; Gangl, Katharina; Kirchler, Erich; Stark, Jennifer

2014-01-01

Both coercion, such as strict auditing and the use of fines, and legitimate procedures, such as assistance by tax authorities, are often discussed as means of enhancing tax compliance. However, the psychological mechanisms that determine the effectiveness of each strategy are not clear. Although highly relevant, there is rare empirical literature examining the effects of both strategies applied in combination. It is assumed that coercion decreases implicit trust in tax authorities, leading to the perception of a hostile antagonistic tax climate and enforced tax compliance. Conversely, it is suggested that legitimate power increases reason-based trust in the tax authorities, leading to the perception of a service climate and eventually to voluntary cooperation. The combination of both strategies is assumed to cause greater levels of intended compliance than each strategy alone. We conducted two experimental studies with convenience samples of 261 taxpayers overall. The studies describe tax authorities as having low or high coercive power (e.g., imposing lenient or severe sanctions) and/or low or high legitimate power (e.g., having nontransparent or transparent procedures). Data analyses provide supportive evidence for the assumptions regarding the impact on intended tax compliance. Coercive power did not reduce implicit trust in tax authorities; however, it had an effect on reason-based trust, interaction climate, and intended tax compliance if applied solely. When wielded in combination with legitimate power, it had no effect. PMID:26074656

[Extralegal coercive measures in psychiatric wards-- patients' perspectives].

PubMed

Jensen, Hans Mørch; Poulsen, Henrik Day

2006-02-06

A revision of the Danish Mental Health Act is planned to take place in 2005-2006. The Ministry of Health requires investigation into whether extralegal coercive measures take place in psychiatric wards. Extralegal coercion refers to restrictions and rules not included in the current Mental Health Act and considered by patients to be coercion. Twenty-two psychiatric patients participated in four group interviews directed by two physicians at four University Hospitals in Copenhagen, Denmark. The patients were asked to define what they perceived as extralegal coercion, house rules and psychiatric treatment. The majority of patients perceived lack of single rooms, restrictions on leaving the ward and shielding, i.e., being confined to one's room, to be extralegal coercion. A few also found the pressure to take medication and collection of clothes items to be extralegal coercion. Rules on smoking, clothing, day and night routines, the use of radio and TV, drugs, alcohol, visits, eating and the use of telephones were considered not extralegal coercion but necessary house rules. House rules should be clear and stated in writing. Restrictions on the use of money and locking of the front door at night were accepted in certain situations, hence not considered to be extralegal coercion. Extralegal coercion does occur in psychiatric wards but in certain situations is accepted if documented. House rules are considered to be necessary and not extralegal coercion. Increased use of compulsory protocols for documenting coercive measures was not considered to be necessary, but documentation in patients' files was useful alternative.

High energy product permanent magnet having improved intrinsic coercivity and method of making same

DOEpatents

Ramesh, Ramamoorthy; Thomas, Gareth

1990-01-01

A high energy rare earth-ferromagnetic metal permanent magnet is disclosed which is characterized by improved intrinsic coercivity and is made by forming a particulate mixture of a permanent magnet alloy comprising one or more rare earth elements and one or more ferromagnetic metals and forming a second particulate mixture of a sintering alloy consisting essentially of 92-98 wt. % of one or more rare earth elements selected from the class consisting of Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures of two or more of such rare earth elements, and 2-8 wt. % of one or more alloying metals selected from the class consisting of Al, Nb, Zr, V, Ta, Mo, and mixtures of two or more of such metals. The permanent magnet alloy particles and sintering aid alloy are mixed together and magnetically oriented by immersing the mixture in an axially aligned magnetic field while cold pressing the mixture. The compressed mixture is then sintered at a temperature above the melting point of the sintering aid and below the melting point of the permanent magnet alloy to thereby coat the particle surfaces of the permanent magnetic alloy particles with the sintering aid while inhibiting migration of the rare earth element in the sintering aid into the permanent magnet alloy particles to thereby raise the intrinsic coercivity of the permanent magnet alloy without substantially lowering the high energy of the permanent magnet alloy.

Coercive family process and early-onset conduct problems from age 2 to school entry.

PubMed

Smith, Justin D; Dishion, Thomas J; Shaw, Daniel S; Wilson, Melvin N; Winter, Charlotte C; Patterson, Gerald R

2014-11-01

The emergence and persistence of conduct problems (CPs) during early childhood is a robust predictor of behavior problems in school and of future maladaptation. In this study we examined the reciprocal influences between observed coercive interactions between children and caregivers, oppositional and aggressive behavior, and growth in parent report of early childhood (ages 2-5) and school-age CPs (ages 7.5 and 8.5). Participants were drawn from the Early Steps multisite randomized prevention trial that includes an ethnically diverse sample of male and female children and their families (N = 731). A parallel-process growth model combining latent trajectory and cross-lagged approaches revealed the amplifying effect of observed coercive caregiver-child interactions on children's noncompliance, whereas child oppositional and aggressive behaviors did not consistently predict increased coercion. The slope and initial levels of child oppositional and aggressive behaviors and the stability of caregiver-child coercion were predictive of teacher-reported oppositional behavior at school age. Families assigned to the Family Check-Up condition had significantly steeper declines in child oppositional and aggressive behavior and moderate reductions in oppositional behavior in school and in coercion at age 3. Results were not moderated by child gender, race/ethnicity, or assignment to the intervention condition. The implications of these findings are discussed with respect to understanding the early development of CPs and to designing optimal strategies for reducing problem behavior in early childhood with families most in need.

Deep Magnetic Diagenesis in Sediments: Progressive and Punctuated Processes.

NASA Astrophysics Data System (ADS)

Musgrave, R. J.; Kars, M. A. C.; Vega, M. E.

2017-12-01

Magnetic diagenesis in the tuffaceous muds, mudstones and volcaniclastic rocks cored at IODP Site U1437 is a product of progressive processes that continue throughout the 1800-m-thick sequence, punctuated by superimposed features corresponding to a series of influxes of fluids and concentrations of hydrocarbons. XRD, visual examination and SEM images indicate the presence of both magnetite and the magnetic sulfide greigite. Inferences from high values of saturation isothermal remanence normalised by magnetic susceptibility (SIRM/χ), distribution of hysteresis data near a diagenetic greigite curve on a Day plot, and 'humping' of low-temperature cycles of SIRM suggest that detrital magnetite and diagenetic greigite are both significant contributors to the magnetic assemblage, with greigite constituting a higher proportion in shallower samples. Progressive magnetic diagenesis is expressed as a continuing background decrease in SIRM/χ. FORC curves indicate an initial diagenetic growth of one or more higher-coercivity phases, followed downhole by increasing loss of all but low-coercivity material. The downhole pattern is consistent with progressive loss of fine-grained magnetite, initial authigenesis of greigite, and progressive pyritisation of the greigite. Some coarse-grained samples from the base of the sequence buck the trend, exhibiting SD behavior probably related to surviving magnetite inclusions in silicates. Shipboard fluid analysis revealed a complex profile of interstitial-water geochemistry, marked by several fluid influxes, including inputs of sulfate-rich water at about 275 and 460 meters below seafloor (mbsf). Methane concentrations, mostly low, markedly increase in the interval between 750 and 1460 mbsf, and ethane appears below an inferred fault at 1104 mbsf. Each of these fluid events is marked by offsets in the rock magnetic parameters SIRM/χ, S-0.3T, and DJH, representing repeated phases of late diagenetic growth of greigite in response to supplies of sulfate, intervals of enhanced pyritisation of greigite where concentrations of deeply sourced methane may be accompanied by H2S, and a more enigmatic response to the thermogenic ethane interval which seems to both dissolve any remaining fine-grained magnetite and grow a new generation of greigite.

Couple experiences of provider-initiated couple HIV testing in an antenatal clinic in Lusaka, Zambia: lessons for policy and practice.

PubMed

Musheke, Maurice; Bond, Virginia; Merten, Sonja

2013-03-14

Couple HIV testing has been recognized as critical to increase uptake of HIV testing, facilitate disclosure of HIV status to marital partner, improve access to treatment, care and support, and promote safe sex. The Zambia national protocol on integrated prevention of mother-to-child transmission of HIV (PMTCT) allows for the provision of couple testing in antenatal clinics. This paper examines couple experiences of provider-initiated couple HIV testing at a public antenatal clinic and discusses policy and practical lessons. Using a narrative approach, open-ended in-depth interviews were held with couples (n = 10) who underwent couple HIV testing; women (n = 5) and men (n = 2) who had undergone couple HIV testing but were later abandoned by their spouses; and key informant interviews with lay counsellors (n = 5) and nurses (n = 2). On-site observations were also conducted at the antenatal clinic and HIV support group meetings. Data collection was conducted between March 2010 and September 2011. Data was organised and managed using Atlas ti, and analysed and interpreted thematically using content analysis approach. Health workers sometimes used coercive and subtle strategies to enlist women's spouses for couple HIV testing resulting in some men feeling 'trapped' or 'forced' to test as part of their paternal responsibility. Couple testing had some positive outcomes, notably disclosure of HIV status to marital partner, renewed commitment to marital relationship, uptake of and adherence to treatment and formation of new social networks. However, there were also negative repercussions including abandonment, verbal abuse and cessation of sexual relations. Its promotion also did not always lead to safe sex as this was undermined by gendered power relationships and the desires for procreation and sexual intimacy. Couple HIV testing provides enormous bio-medical and social benefits and should be encouraged. However, testing strategies need to be non-coercive. Providers of couple HIV testing also need to be mindful of the intimate context of partner relationships including couples' childbearing aspirations and lived experiences. There is also need to make antenatal clinics more male-friendly and responsive to men's health needs, as well as being attentive and responsive to gender inequality during couselling sessions.

First-order reversal curves of single domain particles: diluted random assemblages and chains

NASA Astrophysics Data System (ADS)

Egli, R.

2009-04-01

Exact magnetic models can be used to calculate first-order reversal curves (FORC) of single domain (SD) particle assemblages, as shown by Newell [2005] for the case of isolated Stoner-Wohlfarth particles. After overcoming experimental difficulties, a FORC diagram sharing many similarities to Newell's model has been measured on a lake sediment sample (see A.P. Chen et al., "Quantification of magnetofossils using first-order reversal curves", EGU General Assembly 2009, Abstracts Vol. 11, EGU2009-10719). This sample contains abundant magnetofossils, as shown by coercivity analysis and electron microscopy, therefore suggesting that well dispersed, intact magnetosome chains are the main SD carriers. Subtle differences between the reversible and the irreversible contributions of the measured FORC distribution suggest that magnetosome chains might not be correctly described by the Stoner-Wohlfarth model. To better understand the hysteresis properties of such chains, a simple magnetic model has been implemented, taking dipole-dipole interactions between particles within the same chain into account. The model results depend on the magnetosome elongation, the number of magnetosomes in a chain, and the gap between them. If the chain axis is subparallel to the applied field, the magnetic moment reverses by a pseudo-fanning mode, which is replaced by a pseudo-coherent rotation mode at greater angles. These reversal modes are intrinsically different from coherent rotation assumed Stoner-Wohlfarth model, resulting in FORC diagrams with a smaller reversible component. On the other hand, isolated authigenic SD particles can precipitate in the sediment matrix, as it might occur for pedogenic magnetite. In this case, an assembly of randomly located particles provides a possible model for the resulting FORC diagram. If the concentration of the particles is small, each particle is affected by a random interaction field whose statistical distribution can be calculated from first principles. In this case, the irreversible component of the FORC diagram, which is described by a Dirac delta function in the non-interacting case, converts into a continuous function that directly reflects the distribution of interaction fields. Such models provide a way to identify and characterize authigenic SD particles in sediments, and in some case allow one to isolate their magnetic contribution from that of other magnetic components. Newell, A.J. (2005), A high-precision model of first-order reversal curve (FORC) functions for single-domain ferromagnets with uniaxial anisotropy, Gechem. Geophys. Geosyst., 6, Q05010, doi:10.1029/2004GC00877.

Mexicano Resistance to Schooling in a South Texas Colony

ERIC Educational Resources Information Center

Smith, W. Elwood; Foley, Douglas E.

1978-01-01

This study of Mexicano resistance against coercive identity formation (schooled ethnicity) in a small south Texas town focuses on a particular facet of ethnic selfhood: awareness of the self as a social power wielder. (Author)

The Anxiety of Learning. The HBR Interview.

ERIC Educational Resources Information Center

Coutu, Diane L.

2002-01-01

Psychologist Edgar Schein draws parallels between prisoner-of-war camps and corporate learning organizations. For individuals in both environments, he contends, learning is a coercive process that can be used for both deplorable and acceptable ends. (Author/JOW)

Electromechanical coupling and temperature-dependent polarization reversal in piezoelectric ceramics.

PubMed

Weaver, Paul M; Cain, Markys G; Correia, Tatiana M; Stewart, Mark

2011-09-01

Electrostriction plays a central role in describing the electromechanical properties of ferroelectric materials, including widely used piezoelectric ceramics. The piezoelectric properties are closely related to the underlying electrostriction. Small-field piezoelectric properties can be described as electrostriction offset by the remanent polarization which characterizes the ferroelectric state. Indeed, even large-field piezoelectric effects are accurately accounted for by quadratic electrostriction. However, the electromechanical properties deviate from this simple electrostrictive description at electric fields near the coercive field. This is particularly important for actuator applications, for which very high electromechanical coupling can be obtained in this region. This paper presents the results of an experimental study of electromechanical coupling in piezoelectric ceramics at electric field strengths close to the coercive field, and the effects of temperature on electromechanical processes during polarization reversal. The roles of intrinsic ferroelectric strain coupling and extrinsic domain processes and their temperature dependence in determining the electromechanical response are discussed.

Insight, social knowledge and working memory in schizophrenia.

PubMed

Upthegrove, Rachel; Oyebode, Femi; George, Mohan; Haque, M Sayeed

2002-01-01

There is evidence that insight and social judgements are impaired in schizophrenia. The influence of these factors on the decision to treat compulsorily in schizophrenia is poorly understood. To investigate the contribution of insight, social knowledge, and working memory to the determination to treat coercively in schizophrenia. Insight rating scale, social knowledge questionnaire and working memory tests were administered to detained patients with schizophrenia. Results were compared with those of a control group of voluntary in-patients with schizophrenia. Detained patients scored worse on insight and social knowledge, yet there was no significant correlation between these scores. There was no significant difference in severity of psychopathology between the experimental and control groups. Results for working memory were inconclusive. Insight and social knowledge are significantly, but independently, associated with the determination to treat coercively in schizophrenia. This suggests that insight and social knowledge are distinct skills. The contribution of working memory remains unclear. Copyright 2002 S. Karger AG, Basel

When Push Comes to Shove: A Comparative Concept Analysis of Motivation and Coercion in Nursing Education.

PubMed

Miller, Valerie N

2016-07-01

Understanding the fine line between motivation and coercion in nursing education may offer insight into satisfaction and autonomy in young nursing students, leading to increased retention, effectiveness, and professionalism in the workplace. To compare and analyze the concepts of motivation and coercion with application to nursing academia. Using the Walker and Avant method for concept analyses, definitions and defining attributes of motivation and coercion were identified, along with antecedents, consequences, and model cases for each concept. Comparison of the concepts noting comparative terms and notable differences are presented. The comparison of the concepts of motivation and coercion reveals the stark contrast in the consequences of motivational and coercive power interactions in creating professional, satisfied, and empowered nurses. Nurse educators should seek to identify the best ways to create autonomy, competence, and relatedness in their graduates while minimizing coercive power plays which foster distance and dependence. Miller. © 2015 Wiley Periodicals, Inc.

Violence, addiction, recovery: An anthropological study of Mexico's anexos.

PubMed

Garcia, Angela; Anderson, Brian

2016-08-01

Informal, coercive residential centers for the treatment of addiction are widespread and growing throughout Latin America. In Mexico these centers are called "anexos" and they are run and utilized by low-income individuals and families with problems related to drugs and alcohol. This article draws on findings from a 3-year anthropological study of anexos in Mexico City. Participant observation and in-depth interviews were used to describe and analyze anexos, their therapeutic practices, and residents' own accounts of addiction and recovery. Our findings indicate that poverty, addiction, and drug-related violence have fueled the proliferation of anexos They also suggest that anexos offer valuable health, social, and practical support, but risk exacerbating the suffering of residents through coercive rehabilitation techniques. Emphasizing this tension, this article considers the complex relationship between coercion and care, and poses fundamental questions about what drug recovery consists of in settings of poverty and violence. © The Author(s) 2016.

Topology optimization of reduced rare-earth permanent magnet arrays with finite coercivity

NASA Astrophysics Data System (ADS)

Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Rowe, A.

2018-05-01

The supply chain risk of rare-earth permanent magnets has yielded research efforts to improve both materials and magnetic circuits. While a number of magnet optimization techniques exist, literature has not incorporated the permanent magnet failure process stemming from finite coercivity. To address this, a mixed-integer topology optimization is formulated to maximize the flux density of a segmented Halbach cylinder while avoiding permanent demagnetization. The numerical framework is used to assess the efficacy of low-cost (rare-earth-free ferrite C9), medium-cost (rare-earth-free MnBi), and higher-cost (Dy-free NdFeB) permanent magnet materials. Novel magnet designs are generated that produce flux densities 70% greater than the segmented Halbach array, albeit with increased magnet mass. Three optimization formulations are then explored using ferrite C9 that demonstrates the trade-off between manufacturability and design sophistication, generating flux densities in the range of 0.366-0.483 T.

Evaluation of a sexual assault education/prevention program for male U.S. Navy personnel.

PubMed

Rau, Terri J; Merrill, Lex L; McWhorter, Stephanie K; Stander, Valerie A; Thomsen, Cynthia J; Dyslin, Christopher W; Crouch, Julie L; Rabenhorst, Mandy M; Milner, Joel S

2010-06-01

A randomized clinical trial was conducted to evaluate the effectiveness of the Navy Sexual Assault Intervention Training (SAIT) program for men. A four-group Solomon design was used to control for possible pretest sensitization effects. Male Navy personnel (N = 1,505) were assessed for rape knowledge, rape myth acceptance (two scales), and rape empathy after participating in the SAIT program or viewing an educational video about HIV/AIDS (comparison condition). The SAIT program was found to be effective in increasing rape knowledge, reducing rape myth acceptance, and increasing empathy for rape victims. As expected, men who had exhibited previous coercive sexual behavior, compared with those who had not, reported lower levels of knowledge, higher levels of rape myth acceptance, and less rape empathy. However, the SAIT program was generally effective in changing men's knowledge, beliefs, and feelings on the key measures, regardless of participants' histories of coercive sexual behavior.

Universal Ferroelectric Switching Dynamics of Vinylidene Fluoride-trifluoroethylene Copolymer Films

PubMed Central

Hu, Wei Jin; Juo, Deng-Ming; You, Lu; Wang, Junling; Chen, Yi-Chun; Chu, Ying-Hao; Wu, Tom

2014-01-01

In this work, switching dynamics of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer films are investigated over unprecedentedly wide ranges of temperature and electric field. Remarkably, domain switching of copolymer films obeys well the classical domain nucleation and growth model although the origin of ferroelectricity in organic ferroelectric materials inherently differs from the inorganic counterparts. A lower coercivity limit of 50 MV/m and 180° domain wall energy of 60 mJ/m2 are determined for P(VDF-TrFE) films. Furthermore, we discover in copolymer films an anomalous temperature-dependent crossover behavior between two power-law scaling regimes of frequency-dependent coercivity, which is attributed to the transition between flow and creep motions of domain walls. Our observations shed new light on the switching dynamics of semi-crystalline ferroelectric polymers, and such understandings are critical for realizing their reliable applications. PMID:24759786

Effects of grain size on the properties of bulk nanocrystalline Co-Ni alloys

NASA Astrophysics Data System (ADS)

Qiao, Gui-Ying; Xiao, Fu-Ren

2017-08-01

Bulk nanocrystalline Co78Ni22 alloys with grain size ranging from 5 nm to 35 nm were prepared by high-speed jet electrodeposition (HSJED) and annealing. Microhardness and magnetic properties of these alloys were investigated by microhardness tester and vibrating sample magnetometer. Effects of grain size on these characteristics were also discussed. Results show that the microhardness of nanocrystalline Co78Ni22 alloys increases following a d -1/2-power law with decreasing grain size d. This phenomenon fits the Hall-Petch law when the grain size ranges from 5 nm to 35 nm. However, coercivity H c increases following a 1/d-power law with increasing grain size when the grain size ranges from 5 nm to 15.9 nm. Coercivity H c decreases again for grain sizes above 16.6 nm according to the d 6-power law.

Remanent magnetization and coercivity of rocks under hydrostatic pressure up to 1.4 GPa

NASA Astrophysics Data System (ADS)

Demory, F.; Rochette, P.; Gattacceca, J.; Gabriel, T.; Bezaeva, N. S.

2013-08-01

We designed an Isothermal Remanent Magnetization (IRM) acquisition system based on permanent magnets and sized to accommodate an amagnetic hydrostatic pressure cell. This pressure cell fits in a superconducting rock magnetometer, allowing for the measurement of remanent magnetization of pressurized samples. With this system, we determined the coercivity of remanence (Bcr) at different hydrostatic pressures up to 1.4 GPa for rock and dispersed mineral samples with various magnetic mineralogy and domain state. IRM and Bcr are nearly identical before compression and after decompression, indicating no permanent changes in the magnetic properties during pressure cycling. Hydrostatic pressure up to 1.4 GPa does not significantly increases IRM under pressure except for multidomain pyrrhotite and magnetite which show an increase of about 40%. Relative increase of Bcr under pressure is mild, except for a near single domain titanomagnetite where Bcr doubles.

Effect of primary amines on magnetic properties of Fe-Ni films electroplated in a DES-based plating bath

NASA Astrophysics Data System (ADS)

Yanai, T.; Akiyoshi, T.; Yamaguchi, T.; Takashima, K.; Morimura, T.; Nakano, M.; Fukunaga, H.

2018-05-01

Fe-Ni alloy films were electroplated in DES-based plating baths with various primary amines, and we investigated the effect of the primary amines on the magnetic and the structural properties of the films. The primary amines of ammonium sulfamate, DL-α-alanine and L-glutamic acid reduced the coercivity and the surface roughness of the Fe-rich films (Fe > 70 at.%), and the reduction tendencies of the coercivity and the roughness show good agreement with the result of our previous study on another primary amine of glycine. From the results for the TEM observation, we found that the texture of the Fe-rich film is clearly different from that for the Fe-poor one (Fe < 30 at.%), and we concluded that the primary amines are effective additives for the Fe-rich films electroplated in the DES-based plating baths.

Violence, addiction, recovery: An anthropological study of Mexico’s anexos

PubMed Central

Garcia, Angela; Anderson, Brian

2017-01-01

Informal, coercive residential centers for the treatment of addiction are widespread and growing throughout Latin America. In Mexico these centers are called “anexos” and they are run and utilized by low-income individuals and families with problems related to drugs and alcohol. This article draws on findings from a 3-year anthropological study of anexos in Mexico City. Participant observation and in-depth interviews were used to describe and analyze anexos, their therapeutic practices, and residents’ own accounts of addiction and recovery. Our findings indicate that poverty, addiction, and drug-related violence have fueled the proliferation of anexos. They also suggest that anexos offer valuable health, social, and practical support, but risk exacerbating the suffering of residents through coercive rehabilitation techniques. Emphasizing this tension, this article considers the complex relationship between coercion and care, and poses fundamental questions about what drug recovery consists of in settings of poverty and violence. PMID:27535824

Tailoring of magnetoimpedance effect and magnetic softness of Fe-rich glass-coated microwires by stress- annealing.

PubMed

Zhukova, V; Blanco, J M; Ipatov, M; Churyukanova, M; Taskaev, S; Zhukov, A

2018-02-16

There is a pressing need for improving of the high-frequency magneto-impedance effect of cost-effective soft magnetic materials for use in high-performance sensing devices. The impact of the stress-annealing on magnetic properties and high frequency impedance of Fe-rich glass-coated microwires was studied. Hysteresis loops of Fe-rich microwires have been considerably affected by stress- annealing. In stress-annealed Fe- rich microwire we obtained drastic decreasing of coercivity and change of character of hysteresis loop from rectangular to linear. By controlling stress-annealing conditions (temperature and time) we achieved drastic increasing (by order of magnitude) of giant magnetoimpedance ratio. Coercivity, remanent magnetization, diagonal and of-diagonal magnetoimpedance effect of Fe-rich microwires can be tuned by stress-annealing conditions: annealing temperature and time. Observed experimental results are discussed considering relaxation of internal stresses, compressive "back-stresses" arising after stress annealing and topological short range ordering.

Magnetic properties of cobalt ferrite synthesized by mechanical alloying

NASA Astrophysics Data System (ADS)

Dedi, Idayanti, Novrita; Kristiantoro, Tony; Alam, Ginanjar Fajar Nur; Sudrajat, Nanang

2018-05-01

Cobalt ferrite (CoFe2O4) is a well-known hard magnetic material with high coercivity and moderate magnetization. These properties, along with their great physical and chemical stability, make CoFe2O4 suitable for many applications such as generator, audio, video-tape etc. In this study, the magnetic properties of cobalt ferrite synthesized via the mechanical alloying using α-Fe2O3 of Hot Strip Mill (HSM) waste and cobalt carbonate as the precursors have been investigated. Structural and magnetic properties were systematically investigated. The X-ray diffraction (XRD) pattern exhibited the single phase of cobalt ferrite when the sintering temperature was 1000 °C. Permagraph measurements of the sintered sample revealed a saturation magnetization (Ms) of 77-83 emu/g and coercivity (Hc) of 575 Oe which closely to the magnetic properties of references; Ms = 47.2-56.7 emu/g and Hc =233-2002 Oe.

Influence of Bridgman solidification on microstructures and magnetic behaviors of a non-equiatomic FeCoNiAlSi high-entropy alloy

DOE PAGES

Zuo, Tingting; Yang, Xiao; Liaw, Peter K.; ...

2015-09-07

The non-equiatomic FeCoNiAlSi alloy is prepared by the Bridgman solidification (BS) technique at different withdrawal velocities (V = 30, 100, and 200 μm/s). Various characterization techniques have been used to study the microstructure and crystal orientation. The morphological evolutions accompanying the crystal growth of the alloy prepared at different withdrawal velocities are nearly the same, from equiaxed grains to columnar crystals. The transition of coercivity is closely related to the local microstructure, while the saturation magnetization changes little at different sites. The coercivity can be significantly reduced from the equiaxed grain area to the columnar crystal area when the appliedmore » magnetic field direction is parallel to the crystal growth direction, no matter what is the withdrawal velocity. As a result, the alloy possesses magnetic anisotropy when the applied magnetic field is in different directions.« less

Lipschitz regularity for integro-differential equations with coercive Hamiltonians and application to large time behavior

NASA Astrophysics Data System (ADS)

Barles, Guy; Ley, Olivier; Topp, Erwin

2017-02-01

In this paper, we provide suitable adaptations of the ‘weak version of Bernstein method’ introduced by the first author in 1991, in order to obtain Lipschitz regularity results and Lipschitz estimates for nonlinear integro-differential elliptic and parabolic equations set in the whole space. Our interest is to obtain such Lipschitz results to possibly degenerate equations, or to equations which are indeed ‘uniformly elliptic’ (maybe in the nonlocal sense) but which do not satisfy the usual ‘growth condition’ on the gradient term allowing to use (for example) the Ishii-Lions’ method. We treat the case of a model equation with a superlinear coercivity on the gradient term which has a leading role in the equation. This regularity result together with comparison principle provided for the problem allow to obtain the ergodic large time behavior of the evolution problem in the periodic setting.

Ferroelectriclike and pyroelectric behavior of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shri Prakash, B.; Varma, K. B. R.

2007-02-19

A ferroelectriclike hysteresis loop was obtained at room temperature for CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) ceramic. The remnant polarization and coercive field for 1100 deg. C/5 h sintered CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics were 0.063 {mu}C/cm{sup 2} and 195 V/cm, respectively. Remnant polarization increased while the coercive field decreased with increase in sintering temperature/duration, implying that these were microstructural dependent. The observation of the hysteresis loop for CCTO ceramic was corroborated by its pyroelectric behavior, and the pyroelectric current at room temperature was -0.0028 nA. These findings were attributed to the presence of mixed-valent Ti ions, apart from off centermore » displacement of Ti ions in TiO{sub 6} octahedra.« less