Plutonium waste incineration using pyrohydrolysis

Waste generated by Savannah River Site (SRS) plutonium operations includes a contaminated organic waste stream. A conventional method for disposing of the organic waste stream and recovering the nuclear material is by incineration. When the organic material is burned, the plutonium remains in the incinerator ash. Plutonium recovery from incinerator ash is highly dependent on the maximum temperature to which the oxide is exposed. Recovery via acid leaching is reduced for a high fired ash (>800{degree}C), while plutonium oxides fired at lower decomposition temperatures (400--800{degrees}C) are more soluble at any given acid concentration. To determine the feasibility of using a lower temperature process, tests were conducted using an electrically heated, controlled-air incinerator. Nine nonradioactive, solid, waste materials were batch-fed and processed in a top-heated cylindrical furnace. Waste material processing was completed using a 19-liter batch over a nominal 8-hour cycle. A processing cycle consisted of 1 hour for heating, 4 hours for reacting, and 3 hours for chamber cooling. The water gas shift reaction was used to hydrolyze waste materials in an atmosphere of 336% steam and 4.4% oxygen. Throughput ranged from 0.14 to 0.27 kg/hr depending on the variability in the waste material composition and density

Early History of the Moon: Zircon Perspective

The Moon is believed to have formed from debris produced by a giant impact of a Mars sized body with the Earth (at around 4.51 Ga), forming a primitive body with a thick global layer of melt referred to as the Lunar Magma Ocean (LMO). The crystallization of LMO created internal stratification of the Moon forming main geochemical reservoirs. The surface features on the Moon were shaped by the subsequent collision with several large impactors during a short period of time (3.9-4.0 Ga). This process known as the Late Heavy Bombardment is supported by models of planetary motion, suggesting that rapid migration of giant planets could have triggered a massive delivery of planetesimals from the asteroid belt into the inner Solar System at about 3.9 Ga. Although, general chronology of LMO and LHB is well established using both long lived (U-Pb, Rb-Sr, Sm-147-Nd-143 and Ar-Ar) and extinct (Hf-182-W-182 and 146Sm-142Nd) isotope systems, some of these systems such as Ar-Ar are known to reset easily during secondary thermal overprints. As a result important details in the timing of LMO and LHB remain unresolved. In addition, the relative weakness of these systems under high T conditions can potentially bias the chronological information towards later events in the history of the Moon

Electoral surveys influence on the voting processes: a cellular automata model

Nowadays, in societies threatened by atomization, selfishness, short-term thinking, and alienation from political life, there is a renewed debate about classical questions concerning the quality of democratic decision-making. In this work a cellular automata (CA) model for the dynamics of free elections based on the social impact theory is proposed. By using computer simulations, power law distributions for the size of electoral clusters and decision time have been obtained. The major role of broadcasted electoral surveys in guiding opinion formation and stabilizing the ``{\it status quo}'' was demonstrated. Furthermore, it was shown that in societies where these surveys are manipulated within the universally accepted statistical error bars, even a majoritary opposition could be hindered from reaching the power through the electoral path.Comment: 15 pages, 9 figure

Microdynamics in diverse teams:A review and integration of the diversity and stereotyping literatures

Research on the consequences of diversity in teams continues to produce inconsistent results. We review the recent developments in diversity research and identify two shortcomings. First, an understanding of the microdynamics affecting processes and outcomes in diverse teams is lacking. Second, diversity research has tended to treat different social categories as equivalent and thus not considered how members’ experiences may be affected by their social category membership. We address these shortcomings by reviewing research on stereotypes, which indicates that stereotypes initiate reinforcing microdynamics among (a) attributions of a target team member’s warmth and competence, (b) perceiving members’ behavior toward the target team member, and (c) the target team member’s behavior. Our review suggests that perceivers’ impression formation motivation is the key determinant of the extent to which perceivers continue to treat a target based on categorization. On the basis of our review, we provide an integrative perspective and corresponding model that outlines these MIcrodynamics of Diversity and Stereotyping in Teams (MIDST) and indicates how stereotyping can benefit as well as harm team functioning. We discuss how this integrative perspective on the MIDST relates to the social categorization and the information/decision-making perspective, set a research agenda, and discuss the managerial implications

Determinants of vascular age: An epidemiological perspective

BACKGROUND: Vascular age is an emerging health indicator and predictor of end-organ damage to the heart, brain, and kidney. Although there have been many review publications concerning risk factors for vascular aging, most include cross-sectional epidemiological studies, limiting inferences about temporality. There is a need for a review of longitudinal epidemiological studies with repeated measures of vascular structure and function to allow for a systematic examination of determinants of vascular age and the association of vascular aging with outcomes. CONTENT: Arterial stiffness is the most frequently used measure of vascular aging. We report here results of an extensive literature review of longitudinal cohort studies with repeated measures of arterial stiffness to characterize determinants of vascular age. Additionally, we summarize population-based studies that have focused on the association of arterial stiffness with end-organ damage and adverse cardiovascular outcomes. SUMMARY: Changes in arterial stiffness are evident in early childhood. In adults, arterial stiffness has been observed to progress at the average rate of 0.2 to 0.7 m/s for every 5 years of life. The state of the science is limited by the small number of studies with repeated measures of arterial stiffness and determinants of arterial stiffness progression, as well as limited studies in children and diverse race/ethnic groups. Several extant studies suggest that beyond age, cardiometabolic risk factors and adverse lifestyle behaviors contribute to arterial stiffening. Therefore, arterial stiffness is important in the assessment of healthy vascular aging and a possible target for the prevention of subclinical and clinical disease

Cardiometabolic Health and Carotid-Femoral Pulse Wave Velocity in Children: A Systematic Review and Meta-Regression

Objective: To identify, in children the normal rate of carotid-femoral pulse wave velocity (cfPWV) progression, and whether presence of cardiometabolic risk factors is associated with cfPWV. Study design: Electronic databases (PubMed, Google Scholar) were searched from inception to May 2018, for all studies which reported cfPWV in children (<19 years of age). Random effects meta-regression quantified the association between time (years) and cfPWV, and a systematic review was performed to determine whether cardiometabolic risk factors are associated with cfPWV. Results: Data from 28 articles were eligible for inclusion, including 9 reference value (n = 13 100), 5 cardiovascular risk (n = 5257), 10 metabolic risk (n = 2999), and 8 obesity-focused (n = 8760) studies. Meta-regression findings (9 studies) showed that the increase in cfPWV per year (age) was 0.12 m/second (95% CI, 0.07-0.16 m/second) per year, and when stratified by sex the CIs overlapped. Systematic review findings showed that cardiometabolic risk factors were positively associated with cfPWV, including positive associations with blood pressure, impaired glucose metabolism, and metabolic syndrome. However, obesity was not consistently associated with cfPWV. Conclusions: Arterial stiffness in children progresses with age and is associated with cardiometabolic risk factors. Although further longitudinal studies are warranted, the presented reference data will be valuable to epidemiologists tracking children, and to scientists and clinicians prescribing therapies to mitigate risk in a population that is increasingly more vulnerable to cardiovascular disease

Eutrofiering in Nederland.

Een derde onderzoek is uitgevoerd naar de eutrofieringstoestand in de (semi-) stagnante zoete oppervlaktewateren in ons land. Van 121 plassen en meren werden min of meer volledige gegevens ontvangen betreffende de fysische, chemische en biologische kenmerke

Polycystic Ovary Syndrome Signs and Metabolic Syndrome in Premenopausal Hispanic/Latina Women: the HCHS/SOL Study

Context: Polycystic ovary syndrome (PCOS), a condition of androgen excess in women, is associated with cardiometabolic risk factors; however, this association is not fully characterized in a population-based sample of premenopausal women and high-risk groups such as Hispanics/Latinas. Objective: We examined the association of PCOS signs and metabolic syndrome (MetS) in premenopausal Hispanic/Latina women. Methods: This cross-sectional analysis includes 1427 women age 24 to 44 years from the Hispanic Community Health Study/Study of Latinos. PCOS signs included menstrual cycle greater than 35 days or irregular, self-reported PCOS, and oral contraceptive use to regulate periods or acne, and a composite of 1 or more PCOS signs. We calculated odds ratios (OR) and 95% CI for MetS, accounting for sociodemographic factors and the complex survey design; an additional model included body mass index (BMI). Results: The mean age was 34 years and 30% reported any PCOS sign. The odds of MetS were higher in women reporting cycles greater than 35 days or irregular (OR 1.63; CI: 1.07-2.49) vs cycles 24 to 35 days, self-reported PCOS (OR 2.49; CI: 1.38-4.50) vs no PCOS, and any PCOS sign (OR 1.58; CI: 1.10-2.26) vs none. We found no association between OC use to regulate periods or acne and MetS (OR 1.1; CI: 0.6-1.8). When adjusting for BMI, only the association of self-reported PCOS and MetS was attenuated (OR 1.78; CI: 0.92-3.44). Conclusions: In Hispanic/Latina women, irregular menstrual cycles, self-reported PCOS, and any PCOS sign were associated with MetS and could indicate women at metabolic disease risk

The confined-deconfined Interface Tension and the Spectrum of the Transfer Matrix

The reduced tension $\sigma_{cd}$ of the interface between the confined and the deconfined phase of $SU(3)$ pure gauge theory is related to the finite size effects of the first transfer matrix eigenvalues. A lattice simulation of the transfer matrix spectrum at the critical temperature $T_c = 1/L_t$ yields $\sigma_{cd} = 0.139(4) T_c^2$ for $L_t = 2$. We found numerical evidence that the deconfined-deconfined domain walls are completely wet by the confined phase, and that the confined-deconfined interfaces are rough.Comment: 22 pages, LaTeX file with 4 ps figures included, HLRZ 92-47, BUTP-92/3

Reperfusion in acute myocardial infarction

Studies of the pathophysiology of acute myocardial infarction (AMI) have shown that in most pa- tients a thrombus forms over a ruptured ather- oma in the infarct-related coronary artery and obstructs the artery