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Background:The scale of the 2022 global mpox (formerly known as monkeypox) outbreak has been unprecedented. In less than 6 months, non-endemic countries have reported more than 67 000 cases of a disease that had previously been rare outside of Africa. Mortality has been reported as rare but hospital admission has been relatively common. We aimed to describe the clinical and laboratory characteristics and outcomes of individuals admitted to hospital with mpox and associated complications, including tecovirimat recipients. Methods:In this cohort study, we undertook retrospective review of electronic clinical records and pathology data for all individuals admitted between May 6, and Aug 3, 2022, to 16 hospitals from the Specialist and High Consequence Infectious Diseases Network for Monkeypox. The hospitals were located in ten cities in England and Northern Ireland. Inclusion criteria were clinical signs consistent with mpox and MPXV DNA detected from at least one clinical sample by PCR testing. Patients admitted solely for isolation purposes were excluded from the study. Key outcomes included admission indication, complications (including pain, secondary infection, and mortality) and use of antibiotic and anti-viral treatments. Routine biochemistry, haematology, microbiology, and virology data were also collected. Outcomes were assessed in all patients with available data. Findings:156 individuals were admitted to hospital with complicated mpox during the study period. 153 (98%) were male and three (2%) were female, with a median age of 35 years (IQR 30–44). Gender data were collected from electronic patient records, which encompassed full formal review of clincian notes. The prespecified options for data collection for gender were male, female, trans, non-binary, or unknown. 105 (71%) of 148 participants with available ethnicity data were of White ethnicity and 47 (30%) of 155 were living with HIV with a median CD4 count of 510 cells per mm3(IQR 349–828). Rectal or perianal pain (including proctitis) was the most common indication for hospital admission (44 [28%] of 156). Severe pain was reported in 89 (57%) of 156, and secondary bacterial infection in 82 (58%) of 142 individuals with available data. Median admission duration was 5 days (IQR 2–9). Ten individuals required surgery and two cases of encephalitis were reported. 38 (24%) of the 156 individuals received tecovirimat with early cessation in four cases (two owing to hepatic transaminitis, one to rapid treatment response, and one to patient choice). No deaths occurred during the study period. Interpretation:Although life-threatening mpox appears rare in hospitalised populations during the current outbreak, severe mpox and associated complications can occur in immunocompetent individuals. Analgesia and management of superimposed bacterial infection are priorities for patients admitted to hospital.

Standardizing the Fried criteria (S-FC) using cutoffs specific to the patient population improves adverse outcome prediction. However, there is limited evidence to determine if a S-FC assessment can improve discrimination of cardiovascular disease (CVD) risk in middle-aged and older women.The objective of this cross-sectional analysis was to compare the ability of the Fried frailty phenotype criteria (FC) to discriminate between individuals at higher risk for CVD according to the Framingham Risk Score and Rasmussen Disease Score in comparison to the S-FC.Asper Clinical Research Institute, St. Boniface Hospital Research Centre.985 women 55 years of age or older with no previous history of CVD.Discrimination of individuals with high CVD risk according to the Framingham and Rasmussen Disease scores was assessed using receiver operating characteristic (ROC) curves, integrated discrimination index (IDI) and net reclassification index (NRI).The S-FC showed superior ability to discriminate CVD risk as assessed by area under the ROC curve (AUROC) based on the Framingham (0.728 vs 0.634, p 0.001), but not for the Rasmussen (0.594 vs 0.552, p = 0.079) risk score. Net reclassification index identified improved discrimination for both the Framingham (67.9%, p 0.001) and Rasmussen Disease scores (26.0%, p = 0.003). Integrated discrimination index also identified improved CVD risk discrimination with the Framingham (3.0%, p 0.001) and Rasmussen Disease scores (1.5%, p 0.001).In this study, the Fried frailty phenotype better discriminated cardiovascular disease risk when standardized to the study population.

Self-compassion is associated with many positive outcomes and is generally viewed as an adaptive way of responding during difficult times. But self-compassion has also been positively associated with savoring, a way of responding to positive experiences that involves attempting to sustain or intensify positive emotions, and little is known about the direction of this relationship or whether it generalizes to responses immediately after a positive event. We conducted two studies to learn more about the directionality (Study 1) and generalizability (Study 2) of this relationship. In Study 1, athletes (N = 298) completed assessments of self-compassion and savoring capacity at two time-points throughout a season. We tested a cross-lagged panel model and found that self-compassion predicted increases in savoring, but savoring did not predict change in self-compassion. In Study 2, sports fans (N = 244) reported the extent to which they engaged in savoring immediately after their favorite team had won a championship game. The results showed that self-compassion was positively associated with savoring following the game. Overall, this research reveals more about the directionality and generalizability of the relationship between self-compassion and savoring, and shows that the effects of self-compassion extend to the positive side of the human experience.

Objectives We examined exercisers’ affective and self-presentational reactions to identity confirming or disconfirming feedback in the presence of another person. Design Randomized Experiment. Methods Adult exercisers completed baseline measures prior to a laboratory session. Participants were randomly assigned to receive exercise identity confirming (n = 54) or disconfirming (n = 47) feedback in the presence of a confederate participant. After, participants indicated their level of agreement and completed measures of affect. Lastly, participants were provided with an opportunity for impression construction and completed an additional affect measure. Results A MANOVA comparing groups revealed group differences, F (94, 6) = 31.88, p Discussion Findings provide support for an understudied tenet of identity theory and suggest that exercise identity feedback from others may be a legitimate source of exercise identity feedback.

Seeing oneself as a physically active person is one of the strongest predictors of physical activity behaviour and self-regulatory strategies. Determining whether and how physical activity self-perceptions can be stimulated may help low-active individuals who do not see themselves as a physically active person become more active. Cross-sectional research has tested the Physical Activity Self-Definition (PASD) model among active samples; longitudinal studies among low-active adults have yet to be done. The purpose of this study was to test the predictive power of the PASD model among low-active adults over a 16-week physical activity intervention. Participants completed surveys of validated questionnaires in-person at baseline (pre-intervention) and at 16-weeks (end of intervention) at one of two primary care facilities. The final sample included 119 low-active adults. Partial least squares-structural equation modeling indicated that the original model had small-medium predictive power (Q2 = 0.22; SRMR = 0.13 [0.05, 0.07]; RMSE = 1.13; MAE = 0.9; BIC = 1348.40). Two paths were added in the revised model (perceived wanting—PASD; perceived ability—perceived commitment), which explained an additional 4% and 5% of the variance in perceived commitment (R2 = 0.62 [0.48, 0.72]) and PASD (R2 = 0.74 [0.64, 0.80]; all p’s

Various rate equations for the dissolution of silicate glasses have been discussed in the literature. In this article, the published results from studies are discussed in which the dissolution rate data are collected under high flow conditions such that saturation with respect to alteration products is avoided. Additionally, the studies also covered broad ranges of temperature and pH. Starting with nuclear waste glass studies, a two-term rate expression is used to fit data with the result that the data point toward a three-term expression offered by Kohler et al. (2003). These rate expressions contain two or three pre-exponential or rate constants. However, it appears that a single rate constant, an intrinsic rate constant, is consistent with the data. Thus, a rate expression of the form R = k i exp - E a H + RT a H η H + exp - E a H 2 O RT + exp - E a OH - RT a OH η OH appears to be applicable to a broad range of glasses. Here, R is the rate of dissolution, mol/(m2·s) or similar; E is the activation energy associated with the acid, water, or hydroxide activated reactions, kJ/mol; a is the activity of H+, H2O, or OH−, unitless; η is the order of the reaction with respect to H+, H2O, or OH−; R is the gas constant, kJ/(mol·K); T is the temperature, Kelvin; and ki is the intrinsic rate constant, mol/(m2·s) or similar. The contribution to the overall rate from the ‘water’ term is evident as a minor contribution in the middle pH range for some glass compositions and a major contributor for others. One nuclear waste glass (the Japanese P0798), a basalt glass (Kohler et al., 2003), and a glass with a mineral composition (Bourcier, 1998) exhibit this contribution as a relatively flat response to changes in pH in the range of 5–8. However, to distinguish between the possible rate laws, more experiments and more carefully constrained experimentation are needed. These may include experiments at pH values that differ by as little as 0.25. Lastly, experiments with glasses of different compositions are needed to determine the dependence of the intrinsic rate constant on the glass composition and structure, i.e. non-bridging oxygens, Si–O–Si and Si–O–X (X = a matrix-forming element, e.g. Al or Fe), and other glass structural properties, e.g. binding energies.

Objectives The act of reflecting on physically active possible selves can increase physical activity (PA). According to theory, possible selves that include strategies for achieving them (self-regulatory possible selves) should have the greatest impact on behavior. Our aim was to examine whether forming a self-regulatory physically active possible self is more effective at increasing PA than forming a possible self that focuses only on the image of the possible self (self-enhancing possible self) or engaging in a control activity. Task self-efficacy was examined as a moderator. Design An online, randomized experimental study. Method Insufficiently active adults (n = 244) completed task self-efficacy and PA measures before the intervention, and 4 and 8 weeks after. Results Repeated measures ANOVA revealed a 'time by condition' interaction whereby reported PA levels were higher for participants in the self-enhancing condition than for those in the control condition 4 weeks post-intervention. Reported PA levels were also higher for participants in the self-regulatory condition than those in the control condition at both follow-up time points. There was also a 'time by condition by self-efficacy' interaction, whereby participants in the self-enhancing condition reported more PA than controls at both follow-up points when they also reported high self-efficacy. Participants in the self-regulatory condition reported more physical activity than all other participants when they were also low on self-efficacy, but only at the four-week follow-up point. Conclusion The findings extend the PA possible selves literature by suggesting that different types of possible selves interventions may work best depending on participants' task self-efficacy levels.

The immobilization of radioiodine produced from reprocessing used nuclear fuel is a growing priority for research and development of nuclear waste forms. This review provides a comprehensive summary of the current issues surrounding processing and containment of 129I, the isotope of greatest concern due to its long half-life of 1.6 × 107 y and potential incorporation into the human body. Strategies for disposal of radioiodine, captured by both wet scrubbing and solid sorbents, are discussed, as well as potential iodine waste streams for insertion into an immobilization process. Next, consideration of direct disposal of salts, incorporation into glasses, ceramics, cements, and other phases is discussed. The bulk of the review is devoted to an assessment of various sorbents for iodine and of waste forms described in the literature, particularly inorganic minerals, ceramics, and glasses. This review also contains recommendations for future research needed to address radioiodine immobilization materials and processes.

Engaging in health-promoting behaviours has health benefits for people with prediabetes or diabetes. People experience negative affect after diagnoses, which can impede self-regulation of health behaviours. Self-compassion, extending care to oneself in difficult times, can mitigate negative affect and promote self-regulation. This scoping review explored the relationship between self-compassion and adaptive affect, self-regulation and engagement in health-promoting/management behaviours among people with prediabetes or diabetes. We conducted a scoping literature search from 6 databases for studies and conference abstracts. Randomized controlled trials and cross-sectional, longitudinal, observational and qualitative designs focused on self-compassion were included. Eligible studies included adults with diabetes (prediabetes, type 1, type 2 and gestational), measured self-compassion using a validated Self-Compassion Scale (quantitative) or included the 3 components (qualitative) and investigated: negative affect, health promoting/management behaviours and/or self-regulation. After deduplication, 5,338 quantitative and 953 qualitative abstracts, and 18 conference proceedings were screened leaving 35 articles. Full-text screening retained 11 eligible studies (6 cross-sectional studies, 2 randomized controlled trials, 2 longitudinal studies and 1 qualitative study). Higher self-compassion was associated with decreased negative affect in 9 studies and was positively associated with well-being in 1 cross-sectional study. Self-compassion led to decreased negative affect and improved blood glucose in 2 interventions. Five studies found positive associations between self-compassion and health-promoting/management behaviours. One qualitative study found self-compassion to benefit affective reactions, health-promoting behaviours and self-regulation. This review shows that self-compassion is linked to adaptive behavioural and affective responding among people with prediabetes and diabetes, and the need for more research on self-compassion and self-regulation in these populations.

Epsilon metal (e-metal) is the metallic phase that forms as inclusions at the grain boundaries in the UO2 fuel during reactor operation. This metal is composed of Pd, Mo, Rh, Ru, and Tc. These metallic inclusions are insoluble in strong acid and remnants of these metallic inclusions have been found in the UO2 matrix that remains from the natural reactors in Gabon that were active 1.8 billion years ago, therefore e-metal should be an excellent waste form for the immobilization of the long-lived isotopes 107Pd (6.5 × 106 a) and 99Tc (2.13 × 105 a), with 99Tc being the isotope of interest for repository performance. Therefore, the chemical durability of this potential waste form is assessed in this study. Typically, corrosion rates for metallic materials are measured electrochemically because they are quick, inexpensive, and can reveal the mechanism by which a metal corrodes, at least initially. However, in a repository the waste form would be subjected to slowly flowing water without an applied electrical potential over long time periods. Therefore, the corrosion rates of e-metal specimens were measured with both electrochemical tests and the single-pass flow-through test (SPFT). Potentiodynamic and potentiostatic polarization results suggest that a thin passive film exists on the alloy surface, which seems to be responsible for its high corrosion resistance. Additionally, X-Ray photoelectron spectroscopic results suggest that Pd oxides are significantly enriched in the passive film Results from the SPFT show that the dissolution rates were weakly dependent on pH. Only Mo and Re were found in solution and were used for the calculation of the dissolution rates. In general, the electrochemically determined corrosion rates agree reasonably well with the initial dissolution rate measured with the SPFT test, but they are about one or two orders of magnitude higher than the steady state rates. The causes for this discrepancy are discussed.

We examined the effects of a self-affirmation intervention in conjunction with message frame on attentional bias toward physical activity messages, and explicit psychological and behavioral responses to these messages. Inactive participants (N = 153) completed either a self-affirmation or a control task, were told they were not active enough for health benefits, then read either a gain or loss-framed message, followed by an attentional bias task and questionnaires measuring message processing, psychological reactions and behavior. One week later, participants completed an on-line measure of physical activity. Message frame did not moderate the self-affirmation effect. Self-affirmed participants reported slightly higher self-efficacy for exercising in the future and slightly lower, but not significant, perceived threat than participants in the control group. Self-affirmation and messages may need to be further supplemented with more intense interventions accompanied with adequate resources to facilitate intentions for and actual behavioral change for a complex behavior like physical activity.

Identity theory posits that when people endorse an identity they maintain or alter their behaviour in order to behave consistently with that identity. This assertion is supported in the exercise context where strength of exercise identity relates to exercise behaviour. Less is known about self-regulatory constructs that may aid individuals in behaving consistently with their exercise identity. Self-regulatory efficacy may mediate the relationship between exercise identity and exercise given the influence of this variable on exercise self-regulation; this relationship has not been examined. Exercise identity research has focused on the relationship between identity and behaviour; yet, identity theory recognizes perceptions of identity-behaviour consistency as theoretically important. Through influencing how identity-relevant information is processed, self-regulatory efficacy may also mediate the relationship between exercise identity and perceptions of identity-behaviour consistency. Objective Identity and social cognitive theories were used to examine self-regulatory efficacy as a mediator between exercise identity and i) exercise behaviour and ii) perceptions of identity-behaviour consistency. Method/design Undergraduate students (n = 311) were followed for 8 weeks. At baseline, participants completed demographic, exercise identity and exercise measures. After 4 weeks they reported their self-regulatory efficacy and after 8 weeks they reported their perceptions of identity-behaviour consistency and their exercise behaviour. Results Consistent with theory, self-efficacy mediated the relationship between exercise identity and both outcomes. Conclusions Findings extend the exercise identity literature by providing empirical support for self-regulatory efficacy as a mechanism through which exercise identity strength leads to exercise behaviour and the perception of behavioural consistency with exercise identity meanings.

Problem Positive affect is a determinant of physical and mental health, as well as happiness. Working mothers may miss out on these benefits as they report relatively low positive affect. Physical activity and sleep are associated with the enhancement of positive affect and may offer working mothers an avenue for improving positive affect. This study's main purpose was to examine daily positive affect as a function of physical activity intensity and daily sleep satisfaction among working mothers. A secondary purpose was to examine the possible bi-directional relationship between physical activity intensity and daily sleep satisfaction, given previous evidence of associations between sleep and physical activity. Method In this experience sampling study, 63 physically active working mothers reported the intensity of each physical activity session as well as their daily sleep satisfaction and end-of-day positive affect over 14-days using personal electronic devices. Results Hierarchical Linear Modeling revealed that both previous night sleep satisfaction (t(752) = 3.05, p Discussion These findings suggest that the robust association between daily physical activity and positive affect extends to working mothers and that choosing physical activity as a self-care activity is a good investment for this population.

Understanding the mechanisms that control the durability of nuclear waste glass is paramount if reliable models are to be constructed so that the glass dissolution rate in a given geological repository can be calculated. Presently, it is agreed that (boro)silicate glasses dissolve in water at a rate dependent on the solution concentration of orthosilicic acid (H 4 SiO 4 ) with higher [H 4 SiO 4 ] leading to lower dissolution rates. Once the reaction has slowed as a result of the buildup of H 4 SiO 4 , another increase in the rate has been observed that corresponds to the precipitation of certain silica-bearing alteration products. However, it has also been observed that the concentration of silica-bearing solution species does not significantly decrease, indicating saturation, while other glass tracer elements concentrations continue to increase, indicating that the glass is still dissolving. In this study, we have used the Geochemist’s Workbench code to investigate the relationship between glass dissolution rates and the precipitation rate of a representative zeolitic silica-bearing alteration product, analcime [Na(AlSi 2 O 6 )⋅H 2 O]. To simplify the calculations, we suppressed all alteration products except analcime, gibbsite (Al(OH) 3 ), and amorphous silica. The pseudo-equilibrium-constant matrix for amorphous silica was substituted for the glass pseudo-equilibrium-constant matrix because it has been shown that silicate glasses act as a silica-only solid with respect to kinetic considerations. In this article, we present the results of our calculations of the glass dissolution rate at different values for the analcime precipitation rate constant and the effects of varying the glass dissolution rate constant at a constant analcime precipitation rate constant. From the simulations we conclude, firstly, that the rate of glass dissolution is dependent on the kinetics of formation of the zeolitic phase. Therefore, the kinetics of secondary phase formation is an important parameter that should be taken into account in future glass dissolution modeling efforts. Secondly, the results indicate that, in the absence of a gel layer, the glass dissolution rate controls the rate of analcime precipitation in the long term. The meaning of these results pertinent to long-term glass durability is discussed.

About 1800 years ago a Roman Corbita sunk off the coast of Italy carrying a barrel of glass cullet to the floor of the Adriatic Sea. Samples of glass cullet and the cemented surrounding sediment have been characterized and the reaction between the glass and the sea water saturated with respect to calcite and dolomite has been modeled. Results from characterization and modeling show that the phase surrounding and cementing together the sediment grains is a high-Mg calcite. We find that the origin of this cementing phase is likely the reaction between the glass and the sea water to form a Mg–silicate, here modeled as sepiolite [Mg 4 Si 6 O 15 (OH) 2 ⋅6(H 2 O)].

Epsilon metal (ɛ-metal), an alloy of Mo, Pd, Rh, Ru, and Tc, is being developed as a waste form to treat and immobilize the undissolved solids and dissolved noble metals from aqueous reprocessing of commercial used nuclear fuel. Epsilon metal is an attractive waste form for several reasons: increased durability relative to borosilicate glass, it can be fabricated without additives (100% waste loading), and in addition it also benefits borosilicate glass waste loading by eliminating noble metals from the glass, thus the processing problems related to their insolubility in glass. This work focused on the processing aspects of the epsilon metal waste form development. Epsilon metal is comprised of refractory metals resulting in high alloying temperatures, expected to be 1500–2000 °C, making it a non-trivial phase to fabricate by traditional methods. Three commercially available advanced technologies were identified: spark-plasma sintering, microwave sintering, and hot isostatic pressing, and investigated as potential methods to fabricate this waste form. Results of these investigations are reported and compared in terms of bulk density, phase assemblage (X-ray diffraction and elemental analysis), and microstructure (scanning electron microscopy).

Objective The study had two objectives 1) to test the fit of the Health Action Process Approach (HAPA) model for sport participation among individuals with acquired physical disabilities and 2) to estimate the extent to which athletic identity predicts intentions to engage in sport within the context of HAPA. Design Prospective cohort of 82 women and 19 men with acquired permanent disabilities ( M age = 44.0; M years post-injury = 16.2; % in sport = 61.7%). Method All HAPA indicators and athletic identity were assessed at baseline and sport participation was assessed using the Leisure Time Physical Activity Questionnaire for People with Spinal Cord Injury two weeks later. Structural equation modelling was used to test the HAPA model. Results The HAPA constructs explained 15% of the variance in sport participation and 18% of the variance when athletic identity was added to the model. Instrumental ( β = .21), affective ( β = .15), and negative outcome expectancies ( β = −.20) were significant predictors of intentions to participate in sport, as was athletic identity ( β = .25). Intentions to participate in sport significantly predicted planning ( β = .54) yet there was no direct relationship between planning and sport participation ( β = −.008; p > .05). When the relationship between planning and maintenance self-efficacy was reversed, planning had a significant indirect effect on sport participation through maintenance self-efficacy ( β = .33). Conclusion The HAPA model is a good predictive model for sport participation among those with acquired physical disabilities; furthermore, athletic identity accounts for additional variance in sport participation. These constructs can be valuable components of sport promotion programs for this population.

Role and group identities are distinct yet related constructs. Both identities may be relevant to exercise yet exercise identity research has focused mostly on exercise role identity. Objective We examined the relationship between role and group identity among runners. Further, the relationship of runner role and running group identity were examined relative to social cognitive and behavioural outcomes relative to running and the possibility of running group disbandment. Design An observational design was used. Method Running group members completed measures of runner role and running group identity, self-efficacy for running, and aspects of recent exercise and anticipated reactions to running group disbandment. Results Runner role and running group identity showed a small, positive correlation. Runner role identity was associated with self-efficacy for running, vigorous exercise, less group running and adaptive reactions to the possibility of group disbandment. Running group identity was associated with negative self-efficacy, greater percentage of runs being conducted with the group and maladaptive reactions to group disbandment. Runner role and running group identity did not interact in their relationship to exercise-related outcomes. Conclusions In the context of running, role and group identities are related but unique variables. Identification as a runner may not only be associated with exercise in the context of the group but may also have protective effects against disruptions to group running. Identification with the running group may compromise exercise in the face of group disbandment.

Objectives Identity and Social Cognitive Theories were used to study associations between physical activity (PA) identity, social cognitions (self-regulatory efficacy, proximal intentions), PA, and satisfaction with life among older adults ( M age = 79.5). Methods Eighty-four moderately active older adults completed measures of PA identity, self-regulatory efficacy, proximal intentions, past PA and satisfaction with life. Past PA was hypothesized to relate to PA identity. PA identity and self-regulatory efficacy were hypothesized predictors of proximal PA intentions and satisfaction with life. Differences between identity groups of different strength on PA, social cognitions and satisfaction with life were also explored. Results Regressions revealed the following: Past PA was a significant predictor of PA identity ( Model adj. R 2 = .21; p Model adj. R 2 = .28; p Model adj. R 2 = .21; p p Conclusion Findings support the compatible use of Identity and Social Cognitive Theories in exploring relationships between PA identity for older adults and social cognitions, PA and satisfaction with life. Understanding PA identity for older adults and its relationship to self-regulatory beliefs may generate productive research directions for studying the PA of this underserved population.

A process for the immobilization of intermediate level waste containing a significant quantity of chloride using Ca3(PO4)2 as the host material has been developed. Waste ions are incorporated into two phosphate-based phases, chlorapatite [Ca5(PO4)3Cl] and spodiosite [Ca2(PO4)Cl]. Non-active trials performed using Sm as the actinide surrogate demonstrated the durability of these phases in aqueous solution. Trials of the process, in which actinide-doped materials were used, were performed at PNNL which confirmed the wasteform resistant to aqueous leaching. Initial leach trials conducted on 239Pu/241Am loaded ceramic at 313 K/28 days gave normalized mass losses of 1.2 × 10−5 g m−2 and 2.7 × 10−3 g m−2 for Pu and Cl, respectively. In order to assess the response of the phases to radiation-induced damage, accelerated ageing trials were performed on samples in which the 239Pu was replaced with 238Pu. No changes to the crystalline structure of the waste were detected in the XRD spectra after the samples had experienced an α radiation fluence of 4 × 1018 g−1. Leach trials showed that there was an increase in the P and Ca release rates but no change in the Pu release rate.

This paper describes a simple and practicable method for assigning energy values to gamma-ray pulse-height distributions measured with polyvinyl toluene (PVT) based detectors. It is based upon the characteristic shape of simulated spectra in the region of maximum energy deposition resulting from a single Compton scattering. The validity of this method is demonstrated by applying it to a set of measured NaI(Tl) spectra, and comparing those results to the standard photopeak method of calibrating the same spectra. The method is then applied to a set of measured PVT spectra. It can now be applied to calibration of fielded PVT detectors using two selected gamma-ray sources, which was the initial motivation for this study.

Results from studies of radiation-induced damage from the alpha decay of 238Pu on the density and crystal structure of a nominally phase-pure zirconolite and two other zirconolite-bearing ceramics are discussed. Macro and micro swelling were found to be temperature independent, whereas the density determined with He gas pycnometry was temperature dependent. Approximately 2.6 × 1018 α/g were needed to render the specimens X-ray amorphous– more to saturate the swelling. Unlike pyrochlore-based ceramics, we did not observe any phase changes associated with storage temperature and damage ingrowth. The forward dissolution rate at a pH value of 2 for material containing essentially all zirconolite is 1.7(4) × 10−3 g/(m2 d) with very little pH dependence and no dependence on the amount of radiation-induced damage. Even after the radiation-induced swelling saturated, the specimens remained physically intact with no evidence for microcracking. Thus, the material remains physically a viable material for the disposition of surplus weapons-grade Pu.

Chloride-containing radioactive wastes are generated during the pyrochemical reprocessing of Pu metal. Immobilization of these wastes in borosilicate glass or Synroc-type ceramics is not feasible due to the very low solubility of chlorides in these hosts. Alternative candidates have therefore been sought including phosphate-based glasses, crystalline ceramics and hybrid glass/ceramic systems. These studies have shown that high losses of chloride or evolution of chlorine gas from the melt make vitrification an unacceptable solution unless suitable off-gas treatment facilities capable of dealing with these corrosive by-products are available. On the other hand, both sodium aluminosilicate and calcium phosphate ceramics are capable of retaining chloride in stable mineral phases, which include sodalite, Na8(AlSiO4)6Cl2, chlorapatite, Ca5(PO4)3Cl, and spodiosite, Ca2(PO4)Cl. The immobilization process developed in this study involves a solid state process in which waste and precursor powders are mixed and reacted in air at temperatures in the range 700–800 °C. The ceramic products are non-hygroscopic free-flowing powders that only require encapsulation in a relatively low melting temperature phosphate-based glass to produce a monolithic wasteform suitable for storage and ultimate disposal.

Energy windowing is an algorithmic alarm method that can be applied to plastic scintillator-based radiation portal monitor (RPM) systems to improve operational sensitivity to certain threat sources while reducing the alarm rates from naturally occurring radioactive material. Various implementations of energy windowing have been tested and documented by industry and at Pacific Northwest National Laboratory, and are available in commercial RPMs built by several manufacturers. Moreover, energy windowing is being used in many deployed RPMs to reduce nuisance alarms and improve operational sensitivity during the screening of cargo. This paper describes energy windowing algorithms and demonstrates how these algorithms succeed when applied to “controlled” experimental measurements and “real world” vehicle traffic data.

Laboratory experiments on titanate ceramics were performed to verify whether certain assumptions are valid regarding the swelling, chemical durability, and microcracking that might occur as 239Pu decays. Titanate ceramics are the material of choice for the immobilization of surplus weapons-grade Pu. The short-lived isotope 238Pu, was incorporated into the ceramic formulation to accelerate the effects of radiation-induced damage. We report on the effects of this damage on the density (volumetric swelling

Over the composition range from peraluminous to peralkaline (RPA = Na2O/(Na2O + Al2O3) from 0 to 1), ultraviolet–visible spectroscopy was used to study the local environment of Nd–O in glasses (molar composition): 60SiO2 · 15B2O3 · xNa2O · (25 − x)Al2O3 · yNd2O3 (0 ⩽ x ⩽ 25 and y = solubility limit). Our study focused on Judd–Ofelt oscillator strength parameters: Ω2 – ligand field asymmetry and Ω6 – bond covalence. We explain the similarity between Ω2/Ω6 and the Nd2O3 solubility curve in terms of Nd partitioning into borate- and silicate-rich environments. However, Ω2/Ω6 is nearly independent of RPA for the glasses containing Nd2O3 at the solubility limit irrespective of glass composition, suggesting that average local Nd–O environment is nearly the same for all glasses.

Phase separation in sodium-aluminoborosilicate glasses was systematically studied as a function of Gd 2 O 3 concentration with transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and electron energy loss spectroscopy (EELS) methods. Gadolinium-induced phase separation in the glasses can be consistently explained by proposing that Gd cations partition to the borate-rich environments and subsequent agglomeration of the Gd–borate moieties, or short-range ordered structural groups, in the glass. Agglomeration of the Gd–borate rich environments is further discussed within the context of excess metal oxides, [Na 2 O] ex or [Al 2 O 3 ] ex =|Na 2 O–Al 2 O 3 |, and excess B 2 O 3 , [B 2 O 3 ] ex , available for incorporating Gd cations. Results showed that agglomeration of the Gd–borate rich environments occurred at a much lower Gd 2 O 3 concentration in the glass without [Na 2 O] ex or [Al 2 O 3 ] ex and at a significantly higher Gd 2 O 3 concentration in the glass with either [Na 2 O] ex or [Al 2 O 3 ] ex . Assuming 1BO 4 :1Gd:2BO 3 (based on literature-reported Gd–metaborate structure) as a local Gd–borate environment in glass, we introduced the saturation index of boron, SI [B] =Gd 2 O 3 /(1/3[B 2 O 3 ] ex ), to examine the glass susceptibility to Gd-induced phase separation for all three alkali-aluminoborosilicate systems. While our results have provided some insight to the glass structure, they also provide insight to the mechanism by which the metal oxide is dissolved into the melt. This appears to occur predominately through boron complexation of the metal oxide.

A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studiesmore » of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others.« less

Electron energy loss boron K-edge spectra of gadolinium-bearing sodium aluminoborosilicate glasses were acquired. Extended electron energy loss fine structure studies were performed in both extended and near edge region. Using Gd-metaborate, GdB3O6, as a model, we fitted the experimental B K-edge spectra of the glasses containing 30 and 47 mass% Gd2O3 in r-space with a non-linear least-square fitting method. Based on the results obtained from the current study, the majority of borate units appear to react with Gd cations and the local environment of Gd cations resembles that of the Gd-metaborate structure. Therefore, a distorted Gd-metaborate-like local atomic structure is proposed, in which each Gd cation is stabilized by one tetragonal BO4 unit and two trigonal BO3 units. The similarity of the chemical environment between the two high Gd-bearing glasses implies that the local Gd-metal borate environment, 1BO4:Gd:2BO3, is stable. When the Gd to B ratio in the glasses exceeded 1 to 3 ratio, according to the model, excess Gd cations should form bonds with silicate units. The modeling results are further supported by the energy loss near edge spectra data and previously results obtained from Raman and laser fluorescence deduced phonon side band studies.

In addition to their industrial and consumer-oriented applications, sodium alumino-borosilicate glasses are leading candidates for encapsulation of reprocessed commercial and defense-related nuclear waste. Quantification of the thermochemical and physical properties of these glasses is necessary for a complete understanding of processes occurring in these systems. In this study, 16 glass samples were studied including the base glass (20Na 2 O–15B 2 O 3 –5Al 2 O 3 –60SiO 2 ), six Gd-doped glasses (0.45, 0.92, 1.72, 3.25, 4.74, 7.67, 10.53 mol% Gd 2 O 3 ) and eight Hf-doped glasses (0.15, 0.38, 0.77, 1.57, 3.27, 5.09, 7.06, 11.53 mol % HfO 2 ). Drop solution calorimetry using lead borate solvent at 976 K indicates that these glasses are energetically stable with respect to their binary crystalline oxides. There is a sharp change in the enthalpy of formation between glasses with more than 1.6 mol % Gd 2 O 3 or HfO 2 addition and glasses of lower Gd 2 O 3 or HfO 2 content. At higher doping levels, the apparent partial molar enthalpy of solution of HfO 2 in the glass is close to zero, consistent with the formation of nanometer-sized heterogeneities. A possible explanation is that glasses with more than 1.6 mol% added oxides consist of regions of Gd 2 O 3 or HfO 2 -rich glass perhaps containing regions of medium-range order dominated by Gd 2 O 3 or HfO 2 and/or their nanocrystals and regions of Gd 2 O 3 or HfO 2 poor glass. Glass transition temperatures from DSC experiments indicate similar trends with a change in slope near 1.6 mol % Gd 2 O 3 or HfO 2 . These data are consistent with structural and spectroscopic studies that suggest the onset of clustering and related changes in structure in this composition range.

The vapor hydration test (VHT) is used to study the reaction between waste forms and water with the aim to gain insight into their alteration behavior. In nuclear-waste immobilization, the test is primarily used as a screening tool to identify durable/non-durable glasses and as a convenient method to generate and identify alteration products for use in performance modeling. The lack of a standard procedure for conducting this test has resulted in a number of reported test methods, thus decreasing the ability to directly compare test results from different sources. To optimize the VHT procedure, a series of tests was conducted on simulated low activity waste (LAW) glasses at temperatures ranging from 150 to 300 °C with different volumes of water, specimen holders, specimen-preparation techniques, and data-evaluation methods. Reaction progress was monitored by measuring the thickness of the remaining glass and the alteration layer. The alteration rate at which glass is converted into the alteration products was determined by linear regression from the remaining glass thickness plotted as a function of time. The resulting procedure for conducting VHT eliminates problems associated with the measurement of alteration layers and enables direct comparison of alteration rates for different materials.

A Raman spectroscopy study was performed on a series of sodium-aluminoborosilicate glasses with Gd2O3 from 0 mass% up to its solubility (47 mass% or 13.58 mol%). Experimentally measured spectra were fitted with a Gaussian function for each individual band without any restriction on the band position, width, and intensity. The evolution of the spectroscopic bands appears to result from partitioning of the rare earth cation, as its dissolution mechanism, in these borosilicate glasses. Specifically, the evolution of the Raman bands was correlated well with Gd cations partitioning in the borate-rich environment at low Gd2O3 concentration, Gd2O3/[1/3B2O3] 1. Raman bands near 1420 and 710 cm −1 suggest the presence of a local Gd-metaborate environment, which appeared to occur at all Gd2O3 concentrations. The bands near 300 and 910 cm −1 further suggest the formation of Gd–O–Gd clusters in the silicate-rich environment at high Gd2O3 concentrations.

The basic concepts of thermodynamics and kinetics are discussed in relationship to glass dissolution testing. While it seems like these subjects are too basic to be discussed in a journal article, it is often the case that we forget these concepts when planning and designing dissolution tests and interpreting the results that come from these tests. The possible connection between the composition of the dissolving glass and its long-term behavior is discussed. Results from a preliminary study suggest that the aluminum content of a glass is important to its long-term behavior. The formation of a zeolite can cause the glass dissolution rate to increase under certain conditions that can be modeled. Results indicate that complex glasses can be modeled with a glass containing as little as six components.

Lanthanide-containing glasses, commonly used for optical and laser applications, are also important in the vitrification of actinide-bearing radioactive wastes. In order to study the effect of glass composition on the solubility of gadolinium, 25 peralkaline (Na/Al >1) borosilicate glasses were studied. Above Gd solubility, liquid-liquid phase separation was found in the glasses with Na/B less than 0.5; and in the glasses with Na/B more than 0.5, crystallization was found. For the samples from which liquid-liquid phase separation was observed, Gd solubility was mostly decided by the concentration of excess Na (e.g. Na-Al). Increasing excess Na will increase Gd solubility. For the samples from which crystallization was observed, Gd solubility was decided by the concentration of B, Si, and Al. Increasing B and Si will increase Gd solubility, but increasing Al will decrease Gd solubility. The solution mechanism of Gd in peralkaline borosilicate glasses is also discussed.

This paper discusses the results of a study with 18 peraluminous (Na/Al

Lanthanide-containing glasses, commonly used for optical and laser applications, are also important in the vitrification of actinide-bearing radioactive wastes. In previous studies, we measured the glass forming regions of La2O3 and Gd2O3 in some sodium alumino-borosilicate glasses. Above their highest concentrations in these glasses, lanthanide silicate crystals with an apatite structure were found. In this paper, we characterize these crystals using powder X-ray diffraction (XRD), electron microscopy, energy dispersive spectroscopy (EDS), and selective area diffraction (SAD) to evaluate baseline glass composition effect and mixed La/Gd effect on the structure and chemistry of these crystals. When different lanthanide elements (lanthanum and gadolinium) co-exist in the glasses, complete lanthanide silicate solid solution is observed. Small amounts of boron can enter the gadolinium silicate structure if aluminum is present in the melt. The boron is probably substituting for the silicon in the crystal lattice. This substitution will cause a decrease in the unit cell parameters a0 and c0. A small amount of Na can also enter the crystal lattice, causing a decrease in the cell parameter a0, but an increase in c0. These results may help us to develop better understanding on the solution mechanism of lanthanide oxides in these glasses.

Calculations have been performed to determine why, in static dissolution tests, the experimentally observed formation of a zeolite, such as analcime, causes a rapid increase in the dissolution rate for some glasses but not for others. The results of these calculations with a series of simple glasses show that there is a strong dependence on the Al content of the glass. For ratios of Si/(Si + Al)

The nature of ^*-band, near 188-194 eV, from B K EELS spectra of borate minerals and boron containing glasses has been well documented. The ban results rom teh transition of B 1s to P ^* in B with sp hybridization. Similarly, the higher energy broad band is attributed to the transition from B 1s to P in B Radiation effects on B04 conversion to Bo3 was also studied in details for crystalline solids by Sauer et al.

In recent work at our laboratory, we were re-examining our data and found an inconsistency between the values listed for 137Cs in Table 2 (Siciliano et al. 2008) and results plotted for that source in Figures 11 and 12. In the course of fitting the parabolic function (Equation 4) to the Compton maxima, two ranges of channels were used when determining the parameters for 137Cs. The parabolic fit curve shown in Figure 11 resulted from fitting channels 50 to 70. The parameters for that fit are: are: A = 0.972(12), B = 1.42(24) x 10-3, and CNO = 60.2(5). The parameters for 137Cs listed in Table 2 (and also used to determine the calibration relations in Figure 12—the main result of this paper) came from fitting the 137Cs data in channels 40 to 80. Although the curves plotted from these two different sets of parameters would be visually distinguishable in Figure 11, when incorporated with the other isotope values shown in Figure 12 to obtain the linear energy-channel fit, the 50-70 channel parameter set plus the correction from the Compton maximum to the Compton edge gives a negligible change in the slope [6.470(41) as opposed to the reported 6.454(15) keV/channel]more » and a small change in the intercept [41(8) as opposed to 47(3) keV] for the dashed line. The conclusions of the article therefore do not change as a result of this inconsistency.« less

A one-year leach test at 90/sup 0/C was conducted on specimens of PNL 76-68 borosilicate glass, a simulated nuclear waste glass. The experimental method was MCC-1, one of the standard leach tests developed by the Materials Characterization Center (MCC). The leachant solutions included deionized water, a silicic acid/sodium bicarbonate solution, and a concentrated K-Mg-Na-Cl brine. Phase characterization techniques and geochemical codes were used to identify possible solubility and sorption controls for the constituents dissolved in the final leach solutions. In the non-brine solutions, an alteration layer of 30-50 ..mu..m is formed that consists mainly of an amorphous Fe(OH)/sub 3/. In addition, a zinc silicate phase precipitated on the glass surface and appears to control the concentrations of dissolved Cs and Si. Calculations with the MINTEQ geochemical code identified possible equilbrium solubility controls for dissolved Fe, Ca, Si, Zn, Pb, P, and F. These calculations also permitted an estimation of the pH at the temperature of the leach experiments. The PHREEQE geochemical code was used to predict the steady state concentrations of Ca/sup 2 +/ and Sr/sup 2 +/ in the final leachates by assuming their sorption on solid amorphous Fe(OH)/sub 3/. For the leach tests completed in the brine solution,more » a magnesium silicate phase precipitated on the glass surface and may have been responsible for the observed decrease in the concentration of the dissolved Si. This solid phase was tentatively identified as sepiolite and/or possibly talc. These results were compared to mineral solubilities calculated from the MINTEQ geochemical code.« less

Quantitative recovery and preconcentration of trace amounts of Ce(III), Co(III), Eu(III), Fe(III), Gd(III), Mn(II), Y(III) and Zn(II) ions from nearly saturated brines on the chelating resin Chelex-100 are described. Carrier-free radioactive isotopes were used. Only manganese was significantly affected by the high ionic strength of the brines. Chromium (III) was retained quantitatively by the resin but not eluted quantitatively. The results indicate that transition metal and rare earth ions can be quantitatively preconcentrated from solutions of low and high ionic strength.