ESR Process Instabilities while Melting Pipe Electrodes

With the demonstration of the viability of using the electroslag remelting process for the decontamination of radionuclides, interest has increased in examining the unique aspects associated with melting steel pipe electrodes. These electrodes consist of several nested pipes, welded concentrically to atop plate. Since these electrodes can be half as dense as a solid electrode, they present unique challenges to the standard algorithms used in controlling the melting process. Naturally the electrode must be driven down at a dramatically increased speed. However, since the heat transfer is greatly influenced and enhanced with the increased area to volume ratio, considerable variation in the melting rate of the pipes has been found. Standard control methods can become unstable as a result of the variation at increased speeds, particularly at shallow immersion depths. The key to good control lies in the understanding of the melting process. Several experiments were conducted to observe the characteristics of the melting using two different control modes. By using a pressure transducer to monitor the pressure inside the pipes, the venting of the air trapped inside the electrode was observed. The measurements reveal that for a considerable amount of time. the pipes are not completely immersed in the slag, allowing the gas inside to escape without the formation of bubbles. This result has implications for the voltage swing as well as for the decontamination reactions

Criteria determining the selection of slags for the melt decontamination of radioactively contaminated stainless steel by electroslag remelting

Electroslag remelting is an excellent process choice for the melt decontamination of radioactively contaminated metals. ESR furnaces are easily enclosed and do not make use of refractories which could complicate thermochemical interactions between molten metal and slag. A variety of cleaning mechanisms are active during melting; radionuclides may be partitioned to the slag by means of thermochemical reaction, electrochemical reaction, or mechanical entrapment. At the completion of melting, the slag is removed from the furnace in solid form. The electroslag process as a whole is greatly affected by the chemical and physical properties of the slag used. When used as a melt decontamination scheme, the ESR process may be optimized by selection of the slag. In this research, stainless steel bars were coated with non-radioactive surrogate elements in order to simulate surface contamination. These bars were electroslag remelted using slags of various chemistries. The slags investigated were ternary mixtures of calcium fluoride, calcium oxide, and alumina. The final chemistries of the stainless steel ingots were compared with those predicted by the use of a Free Energy Minimization Modeling technique. Modeling also provided insight into the chemical mechanisms by which certain elements are captured by a slag. Slag selection was also shown to have an impact on the electrical efficiency of the process as well as the surface quality of the ingots produced

Diet of the endangered big-headed turtle \u3cem\u3ePlatysternon megacephalum\u3c/em\u3e

Populations of the big-headed turtle Platysternon megacephalum are declining at unprecedented rates across most of its distribution in Southeast Asia owing to unsustainable harvest for pet, food, and Chinese medicine markets. Research on Asian freshwater turtles becomes more challenging as populations decline and basic ecological information is needed to inform conservation efforts. We examined fecal samples collected from P. megacephalum in five streams in Hong Kong to quantify the diet, and we compared the germination success of ingested and uningested seeds. Fruits, primarily of Machilus spp., were most frequently consumed, followed by insects, plant matter, crabs and mollusks. The niche breadth of adults was wider than that of juveniles. Diet composition differed between sites, which may be attributable to the history of illegal trapping at some sites, which reduced the proportion of larger and older individuals. Digestion of Machilus spp. fruits by P. megacephalum enhanced germination success of seeds by about 30%. However, most digested seeds are likely defecated in water in this highly aquatic species, which limits the potential benefit to dispersal. The results of our study can be used by conservation-related captive breeding programs to ensure a more optimal diet is provided to captive P. megacephalum

Reproductive characteristics of wild female Phayre's leaf monkeys

Understanding female reproductive characteristics is important for assessing fertility, interpreting female behavior, and designing appropriate conservation and captive management plans. In primate species lacking morphological signs of receptivity, such as most colobines, determination of reproductive parameters depends on the analysis of reproductive hormones. Here, we use fecal hormone analysis to characterize cycle patterns ( N =6 females) and gestation length ( N =7 females) in a group of wild Phayre's leaf monkeys ( Trachypithecus phayrei crepusculus ) in Phu Khieo Wildlife Sanctuary, Thailand. We found that both fecal estrogen (fE) and progestin (fP) levels showed clear biological patterns indicative of ovulation and conception. However, because fP patterns were inadequate in determining the end of the luteal phase, we used fE rather than fP patterns to delineate menstrual cycle parameters. We found a mean cycle length of 28.4 days ( N =10), with follicular and luteal phases of 15.4 ( N =10) and 12.5 days ( N =14), respectively. On average, females underwent 3.57 ( N =7) cycles until conception. Average gestation length was 205.3 days ( N =7), with fE levels increasing over the course of pregnancy. Overall, the reproductive characteristics found for Phayre's leaf monkeys were consistent with results for other colobine species, suggesting that fecal hormone monitoring, particularly for fE metabolites, can provide useful reproductive information for this species. Am. J. Primatol. 72:1073–1081, 2010. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78228/1/20866_ftp.pd

Attributes of female rural superintendents leading to success

Female superintendents, while not as rare as they once were, still remain underrepresented when one considers the number of women in the teaching, building leadership, and district leadership ranks. Bolman and Deal’s (2006) framework for leaders provided the context for the attributes attributed to leadership for the purpose of this study. Attributes are delineated as “care-giver, analyst, wizard, and warrior.” Participants shared their leadership positions, both formal and informal, as well as the mentors and coaches that have influenced them along the way. Additionally, the participants discussed the primary means of their own professional development that informs their work in district. Further, the superintendents interviewed discussed their leadership style and the perception of others in their respective districts. Questions that focused on the participants’ definition of success and the barriers to success added to the definition of themselves as leaders, as well as the experiences and perceptions of the leaders themselves. Huffington (2015) provides four lenses of leadership specific to women. These lenses are well-being, wisdom, wonder, and giving. More than using the language of caregiver, analyst, wizard, or warrior, the participants of this study spoke to the balance of working with people in a time of change and angst in education. They spoke to the well-being of their students and staff and caring about the future. Decisions were made to balance the competing needs of the stakeholders. Finally, the participants of this study spoke to the strength of their districts and their communities and the interdependence needed for everyone to thrive during this time of change in education

Letter dated 29 May 1951 to Dr. Atiya from Lyle Stanton Shelmidine

Postscript Letter dated 29 May 1951 to Dr. Atiya from Lyle Stanton Shelmidine, correcting the title of a set of volumes edited by Boquet which he had referenced in an earlier lette

Zookeeper–Animal Bonds and Their Relationship with Conservation Action

Human–animal relationships have been demonstrated to have impacts on animal and keeper welfare, although their impacts on zookeepers have been less studied outside of evaluating job satisfaction. Many zoological facilities are active in supporting conservation initiatives among staff, but current levels of zookeeper engagement in pro-conservation behavior and the motivations behind it are less studied. Some research indicates motivations for pro-environmental action, in general, may include empathetic connections with animals. To investigate connections between zookeeper–animal relationships and conservation participation, 144 zookeepers from various locations participated in an online survey responding to questions about their perception of their relationships with the animals in their care and current conservation participation levels. This study found zookeepers who report bonds with the animals in their care are more likely to participate in select conservation behaviors, such as reducing personal waste, than those who do not claim a bond with animals. Bonds did not predict involvement in larger conservation actions such as habitat restoration or citizen science participation. These findings have implications for how zoos might encourage engagement in pro-conservation behaviors and participation among their staff

Optimization of Thermochemical, Kinetic, and Electrochemical Factors Governing Partitioning of Radionuclides During Melt Decontamination of Radioactively Contaminated Stainless Steel

Metal waste generated from domestic nuclear operations for defense and commercial applications has led to a growing stockpile of radioactively contaminated scrap metal, much of which is stainless steel. This steel contains large quantities of strategic elements such as nickel and chromium and constitutes a valuable domestic resource [1]. A significant fraction of this material cannot be efficiently surface decontaminated, and burial of this material would be wasteful and expensive, since long term monitoring would be necessary in order to minimize environmental risk. Melt decontamination of this material would maintain the chemical pedigree of the stainless steel, allowing its controlled reuse within the nuclear community. This research addresses the melt decontamination of radioactively contaminated stainless steel by electroslag remelting (ESR). ESR is industrially used for the production of specialty steels and superalloys to remove a variety of contaminates and to improve metal chemistry. Correctly applied, it could maintain the specified chemistry and mechanical properties of the original material while capturing the radioactive transuranic elements in a stable slag phase. The ESR process also produces a high quality metal ingot free of porosity that can be directly forged or rolled into final shapes. The goal of this project was to optimize a melt decontamination process through a basic understanding of the factors which govern the partitioning of various radionuclides between the metal, slag, and gas phases. Radionuclides which are captured by a slag phase may be stabilized by promoting the formation of synthetic minerals within a leach resistant matrix. This research program included three segments. At Boston University, Prof. Uday Pal and his group conducted research to develop a fundamental understanding of thermochemical and electrochemical behaviors of slag/metal/radionuclide surrogate systems. This work combined experimental characterization and thermochemical modeling of these high temperature systems. The second segment utilized Sandia expertise and ongoing work in fundamental separation science and liquid metal processing technology to investigate and optimize ESR decontamination using representative surrogate compounds to represent contaminate radionuclides. This work evaluated partitioning of the surrogates between the slag and metal ingot in ESR experiments. Furnace operating parameters were systematically varied to determine the optimum slag processing conditions. The third effort in Russia conducted ESR melting experiments using contaminated stainless steel pipe electrodes doped with plutonium. This work provided separation data for the radioactive compounds