The Organic Secondary Building Unit: Strong Intermolecular π Interactions Define Topology in MIT-25, a Mesoporous MOF with Proton-Replete Channels

Park, Sarah S.,Hendon, Christopher H.,Fielding, Alistair J.,Walsh, Aron,O’Keeffe, Michael,Dincă,, Mircea American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.10

<P>The structure-directing role of the inorganic secondary building unit (SBU) is key for determining the topology of metal organic frameworks (MOFs). Here we show that organic building units relying on strong Ir interactions that are energetically competitive with the formation of common inorganic SBUs can also play a role in defining the topology. We demonstrate the importance of the organic SBU in the formation of Mg2H6(H3O)(TTFTB)(3) (MIT-25), a mesoporous MOF with the new ssp topology. A delocalized electronic hole is critical in the stabilization of the TTF triad organic SBUs and exemplifies a design principle for future MOF synthesis.</P>

FAST irradiations and initial post irradiation examinations – Part I

Beausoleil G.,Capriotti L.,Curnutt B.,Fielding R.,Hayes S.,Wachs D. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11

The Advanced Fuels Campaign Fission Accelerated Steady-state Test (FAST) at Idaho National Laboratory (INL) completed its first irradiation cycle within the Advanced Test Reactor (ATR). The test focused on the irradiation of alloy fuel forms for use in sodium fast reactors. The first cycle of FAST testing was completed and four rodlets were removed for the initial post irradiation examination (PIE). The rodlet design and irradiation conditions were evaluated using Monte Carlo N-Particle (MCNP) for as-run power history and COMSOL for temperature analysis. These rodlets include a set of low burnups (~2.5 % fissions per initial metal atoms [%FIMA]), control rodlets, and a helium-bonded annular rodlet (4.7 %FIMA). Nondestructive PIE has been completed and includes visual inspection, neutron radiography and gamma scanning of the FAST capsules and rodlets. Radiography confirmed the integrity of the experiments, revealed that the annulus in the annular fuel was filled at a modest burnup (4.7 %FIMA), and indicated potential slumping of the cooler rodlets at lower burnup. Precision gamma scanning indicated mostly usual fission product behavior, except for cesium in the He-bonded annular fuel. Future destructive PIE will be necessary to fully interpret the effects of accelerated irradiation on U-Zr metallic fuel behavior

Interaction Studies of Ceramic Vacuum Plasma Spraying For the Melting Crucible Materials

김종환,김형태,우윤명,김기환,이찬복,R. S. Fielding 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.5

Candidate coating materials for re-usable metallic nuclear fuel crucibles, TaC, TiC, ZrC, ZrO2, and Y2O3, were plasmasprayed onto a niobium substrate. The microstructure of the plasma-sprayed coatings and thermal cycling behavior were characterized, and U-Zr melt interaction studies were carried out. The TaC and Y2O3 coating layers had a uniform thickness,and high density with only a few small closed pores showing good consolidation, while the ZrC, TiC, and ZrO2 coatings were not well consolidated with a considerable amount of porosity. Thermal cycling tests showed that the adhesion of the TiC, ZrC,and ZrO2 coating layers with niobium was relatively weak compared to the TaC and Y2O3 coatings. The TaC and Y2O3coatings had better cycling characteristics with no interconnected cracks. In the interaction studies, ZrC and ZrO2 coated rods showed significant degradations after exposure to U-10 wt.% Zr melt at 1600ºC for 15 min., but TaC, TiC, and Y2O3 coatings showed good compatibility with U-Zr melt.

High density of ice krill (Euphausia crystallorophias) in the Amundsen sea coastal polynya, Antarctica

La, H.S.,Lee, H.,Fielding, S.,Kang, D.,Ha, H.K.,Atkinson, A.,Park, J.,Siegel, V.,Lee, S.,Shin, H.C. Pergamon Press ; Elsevier Science Ltd 2015 Deep-sea research. Part I, Oceanographic research Vol.95 No.-

High densities of ice krill Euphausia crystallorophias were observed along six acoustic transects within the Amundsen Sea Coastal Polynya, Antarctica. Two-frequency acoustic backscatter data was examined in the austral summers of January 2011 and February 2012. A dB identification window (S<SUB>v120-38</SUB>) identified ice krill dominating the acoustic backscatter. The density of ice krill, calculated with the stochastic distorted-wave born approximation model, ranged between 4.5 and 30g wet mass m<SUP>-2</SUP> for each transect (a mean of 16g wet mass m<SUP>-2</SUP> for all transects), these high values are an order of magnitude higher than recorded previously in the Ross Sea Polynya. High densities were detected along the ice shelf and near the boundary between pack ice and coastal polynya, and we postulate that these could be important habitats for ice krill. The high densities observed along the transects make ice krill a potentially important, but poorly known contributor to these high-latitude shelf food webs.

Hong Kong Chinese Women's Lay Beliefs about Cervical Cancer Causation and Prevention

Wang, Linda Dong-Ling,Lam, Wendy Wing Tak,Wu, Joseph,Fielding, Richard Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Background: This study aimed to seek insights into Chinese women's lay beliefs about cervical cancer causal attributions and prevention. Materials and Methods: Twenty-three new immigrant adult women from Mainland China and thirty-five Hong Kong adult women underwent semi-structured in-depth interviews. Interviews were audio taped, transcribed and analyzed using a Grounded Theory approach. Results: This study generated three foci: causal beliefs about cervical cancer, perceived risk of cervical cancer, and beliefs about cervical cancer prevention. Personal risky practices, contaminated food and environment pollution were perceived as the primary causes of cervical cancer. New immigrant women more likely attributed cervical cancer to external factors. Most participants perceived cervical cancer as an important common fatal female cancer with increased risk/prevalence. Many participants, particularly new immigrant women participants, expressed helplessness about cervical cancer prevention due to lack of knowledge of prevention, it being perceived as beyond individual control. Many new immigrant participants had never undergone regular cervical screening while almost all Hong Kong participants had done so. Conclusions: Some Chinese women hold pessimistic beliefs about cervical cancer prevention with inadequate knowledge about risk factors. Future cervical cancer prevention programs should provide more information and include capacity building to increase Chinese women's knowledge and self-efficacy towards cervical cancer prevention.

Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

Kim, K.H.,Lee, C.T.,Lee, C.B.,Fielding, R.S.,Kennedy, J.R. North Holland Pub. Co 2013 Journal of nuclear materials Vol.441 No.1

Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450<SUP>o</SUP>C showed that HfN, TiC, ZrC, and Y<SUB>2</SUB>O<SUB>3</SUB> coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550<SUP>o</SUP>C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y<SUB>2</SUB>O<SUB>3</SUB> do not form significant reaction layer between U-20wt.% Zr melt and the coating layer. Plasma-sprayed Y<SUB>2</SUB>O<SUB>3</SUB> coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y<SUB>2</SUB>O<SUB>3</SUB> coating.

Patterns of Cancer-Related Risk Behaviors Among Construction Workers in Hong Kong: A Latent Class Analysis Approach

Xia, Nan,Lam, Wendy,Tin, Pamela,Yoon, Sungwon,Zhang, Na,Zhang, Weiwei,Ma, Ke,Fielding, Richard Occupational Safety and Health Research Institute 2020 Safety and health at work Vol.11 No.1

Background: Hong Kong's construction industry currently faces a manpower crisis. Blue-collar workers are a disadvantaged group and suffer higher levels of chronic diseases, for example, cancer, than the wider population. Cancer risk factors are likely to cluster together. We documented prevalence of cancer-associated lifestyle risk behaviors and their correlates among Hong Kong construction workers. Methods: Data were collected from workers at 37 railway-related construction worksites throughout Hong Kong during May 2014. Tobacco use, alcohol consumption, unbalanced nutrition intake, and physical inactivity were included in the analysis. Latent class analysis and multivariable logistic regression were performed to identify the patterns of risk behaviors related to cancer, as well as their impact factors among construction workers in Hong Kong. Results: Overall, 1,443 workers participated. Latent class analysis identified four different behavioral classes in the sample. Fully adjusted multiple logistic regression identified age, gender, years of Hong Kong residency, ethnicity, educational level, and living status differentiated behavioral classes. Conclusion: High levels of lifestyle-related cancer-risk behaviors were found in most of the Hong Kong construction workers studied. The present study contributes to understanding how cancer-related lifestyle risk behaviors cluster among construction workers and relative impact factors of risk behaviors. It is essential to tailor health behavior interventions focused on multiple risk behaviors among different groups for further enlarging the effects on cancer prevention.

INTERACTION STUDIES OF CERAMIC VACUUM PLASMA SPRAYING FOR THE MELTING CRUCIBLE MATERIALS

Kim, Jong Hwan,Kim, Hyung Tae,Woo, Yoon Myung,Kim, Ki Hwan,Lee, Chan Bock,Fielding, R.S. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.5

Candidate coating materials for re-usable metallic nuclear fuel crucibles, TaC, TiC, ZrC, $ZrO_2$, and $Y_2O_3$, were plasmasprayed onto a niobium substrate. The microstructure of the plasma-sprayed coatings and thermal cycling behavior were characterized, and U-Zr melt interaction studies were carried out. The TaC and $Y_2O_3$ coating layers had a uniform thickness, and high density with only a few small closed pores showing good consolidation, while the ZrC, TiC, and $ZrO_2$ coatings were not well consolidated with a considerable amount of porosity. Thermal cycling tests showed that the adhesion of the TiC, ZrC, and $ZrO_2$ coating layers with niobium was relatively weak compared to the TaC and $Y_2O_3$ coatings. The TaC and $Y_2O_3$ coatings had better cycling characteristics with no interconnected cracks. In the interaction studies, ZrC and $ZrO_2$ coated rods showed significant degradations after exposure to U-10 wt.% Zr melt at $1600^{\circ}C$ for 15 min., but TaC, TiC, and $Y_2O_3$ coatings showed good compatibility with U-Zr melt.

Risk Factors for Failure of Nonoperative Treatment for Unilateral Cervical Facet Fractures

Carola Francisca van Eck,Mitchell Stephen Fourman,Amir Mohamad Abtahi,Louis Alarcon,William Fielding Donaldson,Joon Yung Lee 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.3

Study Design: Retrospective clinical study. Purpose: The purpose of this study was to determine what percentage of patients who underwent nonoperative management of unilateral non-displaced or minimally displaced facet fractures progressed radiographically and to determine what percentage of patients required surgical intervention and to identify risk factors for failure of conservative management. Overview of Literature: According to most commonly used classification systems, unilateral, non-and minimally displaced facet fractures are be amendable to nonoperative management. Methods: A retrospective review of the Trauma Registry of a Level I trauma center was performed to identify all patients diagnosed with a non- or minimally displaced unilateral facet fracture which was managed nonoperatively. Several demographic variables and clinical outcomes were recorded. Using computed tomography scanning and plain radiographs, fracture pattern, listhesis, displacement, angle and percentage of the facet that included the fracture were determined. Radiographic progression was defined as the occurrence of listhesis of more than 10% of the anterior-posterior dimensions of the inferior vertebral body during radiographic follow-up. Failure of conservative management was defined as a patient requiring surgical intervention after initially being managed nonoperatively. Results: Seventy-four patients were included. Fifteen patients (20%) progressed radiographically. However, only 2 developed radicular symptoms and none developed myelopathy or other catastrophic cord related symptoms. Seven patients (9%) underwent surgery. Indications for surgery included significant radiographic progression and/or radicular symptoms. Risk factors for failure of conservative management included presence of radiculopathy at the time of presentation, a higher body mass index, increased Injury Severity Score, greater initial fracture displacement and more than 2 mm of listhesis. Conclusions: Patients with non-displaced or minimally displaced facet fractures who do not have neurological symptoms at the time of presentation can safely be managed conservatively with careful observation and follow-up.

Symmetry breaking in MAST plasma turbulence due to toroidal flow shear

Fox, M F J,Wyk, F van,Field, A R,Ghim, Y-c,Parra, F I,Schekochihin, A A IOP 2017 Plasma physics and controlled fusion Vol.59 No.3

<P>The flow shear associated with the differential toroidal rotation of tokamak plasmas breaks an underlying symmetry of the turbulent fluctuations imposed by the up–down symmetry of the magnetic equilibrium. Using experimental beam-emission-spectroscopy measurements and gyrokinetic simulations, this symmetry breaking in ion-scale turbulence in MAST is shown to manifest itself as a tilt of the spatial correlation function and a finite skew in the distribution of the fluctuating density field. The tilt is a statistical expression of the ‘shearing’ of the turbulent structures by the mean flow. The skewness of the distribution is related to the emergence of long-lived density structures in sheared, near-marginal plasma turbulence. The extent to which these effects are pronounced is argued (with the aid of the simulations) to depend on the distance from the nonlinear stability threshold. Away from the threshold, the symmetry is effectively restored.</P>