Nitrate ion effects on uranium chemistry in the tributylphosphate-dodecane system

Understanding the role of nitrate in the speciation of actinides is important in order to determine the necessary data for extraction modeling of the UREX process. The focus of this project is on the fundamental chemistry of uranium (U) in the tributyl phosphate (TBP) extraction system, with emphasis on the effect of nitrate on actinyl speciation. Speciation calculations can be performed if stability and solubility constants for the chemical species formed under the examined conditions are known. The stability constant of the uranyl-TBP complex was evaluated under a variety of conditions. The variables were nitric acid, uranyl, total nitrate concentration, and ionic strength. The thermodynamic data collected can be incorporated into extraction modeling codes used to predict distribution in reprocessing. The methods used in this research will be modified for corresponding experiments with plutonium and provide necessary data for optimizing the modeling codes

Fundamental Chemistry of U and Pu in the TBP-Dodecane-Nitric Acid System: Quarterly Report January - March, 2006

The speciation of hexavalent U and tetravalent Pu will be examined in the Tributylphosphate (TBP)-dodecane-nitric acid systems. This topic is chosen based on data needs for separation modeling identified by the AFCI. Emphasis will be placed on studying the influence of nitrate and acetohydroxamic acid on U and Pu speciation as well as conditions where a third phase forms in the organic phase. The organic phase will be 30% TBP in dodecane. Equal volumes of aqueous and organic phase will be used. The speciation of the actinides in the aqueous and organic phase will be determined by a number of different spectroscopic and radiochemical techniques. Additionally the actinide distribution between the phases as a function of conditions will be determined. The project data will be incorporated into models to evaluate separations under a variety of conditions. This quarter involved work on extraction samples containing two different uranium concentrations. The samples were analyzed for nitrate and uranium concentrations by IC (ion chromatography) and LSC (liquid scintillation counting), respectively. This data will be helpful in understanding how nitrate and uranium are distributing between the two phases and the dependence of this effect on total nitrate concentration

Fundamental Chemistry of U and Pu in the TBP-Dodecane-Nitric Acid System: Quaterly Report January - March, 2005

The speciation of hexavalent U and tetravalent Pu will be examined in the TBP-dodecane-nitric acid systems. This topic is chosen based on data needs for separation modeling identified by the AFCI. Emphasis will be placed on studying the influence of nitrate and acetohydroxamic acid on U and Pu speciation as well as conditions where a third phase forms in the organic phase. The organic phase will be 30% TBP in dodecane. Equal volumes of aqueous and organic phase will be used. The speciation of the actinides in the aqueous and organic phase will be determined by a number of different spectroscopic and radiochemical techniques. Additionally the actinide distribution between the phases as a function of conditions will be determined. The project data will be incorporated into models to evaluate separations under a variety of conditions

Fundamental Chemistry of U and Pu in the TBP-Dodecane-Nitric Acid System: Quarterly Report

The speciation of hexavalent U and tetravalent Pu will be examined in the TBPdodecane- nitric acid systems. This topic is chosen based on data needs for separation modeling identified by the AFCI. Emphasis will be placed on studying the influence of nitrate and acetohydroxamic acid on U and Pu speciation as well as conditions where a third phase forms in the organic phase. The organic phase will be 30 % TBP in dodecane. Equal volumes of aqueous and organic phase will be used. The speciation of the actinides in the aqueous and organic phase will be determined by a number of different spectroscopic and radiochemical techniques. Additionally the actinide distribution between the phases as a function of conditions will be determined. The project data will be incorporated into models to evaluate separations under a variety of conditions. Work in this quarter focused on 3rd phase formation studies with the uranyl system. which happens with the organic phase spontaneously splits into a light and a heavy phase. This phenomenon occurs when the uranium and nitric acid concentrations exceed a certain threshold. Current theories include that the third phase forms gradually in small reverse micelles when uranyl and nitric acid reach a certain limiting organic concentration (LOC) that makes it thermodynamically favorable to separate and form a different structure. This is analogous to the critical micelle concentration (cmc) in surfactant micelle formation. The third phase formation is quite dependent on temperature. There has been some work indicating that the UV-visible spectrum changes at certain wavelengths as the system approaches third phase, indicating a variation in the uranyl electronic structure as this third phase begins to form

Mom\u27s Day Out: Investigating the Proximate Causes of Allomothering in Squirrel Monkeys

Allomothering, which is defined as non-material infant care, is a behavior that is found among many animal species. Although it is widely acknowledged in primate species in particular, it is not well understood. Allomaternal behavior is well documented but the proximal causes are not known. Most primate species live in groups and have intense social relations which govern every aspect of their behavior. Allomothering could then be better understood by looking at the social relationships that exist between members of a group. This research tries to better understand what causes certain females to allomother over others by looking at the relationships between mothers, allomothers, and the rest of the colony in Peruvian and Guyanese squirrel monkeys. Observational data was collected on captive groups over a five month period by observing huddling groups, those in proximate contact, and kinship relationships. These factors were thought to affect which individuals participated in allomothering. This research found that huddling groups were not significant indicators of which monkeys would participate in allomothering. Proximal contact had the strongest significant effect on allomaternal behavior while kinship had a weaker, yet significant, effect. However, kinship only had an effect when older siblings carried younger siblings. Although huddling partners were found to be an insignificant factor, this research still suggests that social cliques and kinship do in fact have an effect on vllomaternal behavior. One possible reason huddling partners did not have an effect on allomaternal behavior is that because juvenile females do most of the allomothering and females may only huddle with other monkeys that are similar in age. Further research needs to be accomplished on what factors affect this behavior in female squirrel monkeys

Pyloric Stenosis Leading to Sinus Venous Thrombosis; A Case Report

Pyloric stenosis is typically diagnosed early and repaired after resuscitation and electrolyte correction in a timely manner. Delay in diagnosis or presentation of patient can lead to significant morbidity and even mortality. Here we present a case of pyloric stenosis leading to dehydration severe enough to lead to venous sinus thrombosis. This case highlights the importance of early detection of pyloric stenosis with timely correction of fluid status and electrolytes. Venous sinus thrombosis is a serious complication associated with our patient’s pyloric stenosis that has not yet been reported in literature

Embryonal Rhabdomyosarcoma in the Pelvis of a 22-Year-Old Female: A Case Report

Embryonal rhabdomyosarcoma is a rare soft-tissue sarcoma that is responsible for less than 1% of malignancies in the adult population. We present a case of a 22-year-old female with a six-month history of abnormal uterine bleeding that was found to have an exophytic mass within the cervix. Magnetic resonance imaging was performed and revealed a large pelvic mass. Further workup included biopsies and surgical removal of the tumor, leading to the diagnosis of embryonal rhabdomyosarcoma. PET scan showed no FDG-avid malignancy, aiding in the decision-making process for adjuvant treatment to include vincristine, actinomycin D, cyclophosphamide, and mesna. This case is important to document due to the rarity of this disease and to serve as a reminder to gynecologists to consider the addition of rhabdomyosarcoma in the differential diagnosis when evaluating young adult females presenting with abnormal uterine bleeding and a cervical mass lesion

Value Development in Emerging Adulthood: the Influence of Family

The purpose of this study was to better understand value development in an emerging adult, college student population, and to further define, identify and clarify family characteristics that influence values. Theories have sought to examine the developmental influences in emerging adulthood, but little research exists examining the role of the family, particularly in regards to value development. The current study reviewed the literature on emerging adulthood, values, and self-determination theory with attention to family influence. Questions addressed in this study included: 1) are perceived parent values predictors of emerging adult values, 2) will the quality of communication between parents and emerging adults and the presence of an emotionally supportive relationship with both mother and father moderate the relationship between the perception of parent values and emerging adult values, and 3) does the family environment influence the types of values emerging adults perceive to be important to their parents? For this purpose, 200 college students completed 5 different self-report questionnaires measuring the constructs of values, perceived parent values, family environment variables, family communication variables, and quality of relationship with both father and mother. Parents of college students completed a self-report questionnaire measuring their socialization values for their children and a questionnaire measuring family communication; however, the small number of parent responses prevented the data from being used in statistical tests. Multiple regression analyses indicated that perceived parent values predicted emerging adult values. Moderation analyses showed that family communication and the quality of the relationship with father and mother did not strengthen the relationship between perceived parent values and emerging adult values. Lastly, a warm family environment and family activities were significantly related to how important emerging adults’ perceived intrinsic values to be to both their father and mother. Family structure was significantly positively correlated the importance emerging adults’ perceived their fathers to place on extrinsic values, but not their mothers. Implications for the findings of the current study will be discussed, as well as, limitations and future research recommendations

The EGNoG Survey: Gas Excitation in Normal Galaxies at z~0.3

As observations of molecular gas in galaxies are pushed to lower star formation rate galaxies at higher redshifts, it is becoming increasingly important to understand the conditions of the gas in these systems to properly infer their molecular gas content. The rotational transitions of the carbon monoxide (CO) molecule provide an excellent probe of the gas excitation conditions in these galaxies. In this paper we present the results from the gas excitation sample of the Evolution of molecular Gas in Normal Galaxies (EGNoG) survey at the Combined Array for Research in Millimeter-wave Astronomy (CARMA). This subset of the full EGNoG sample consists of four galaxies at z~0.3 with star formation rates of 40-65 M_Sun yr^-1 and stellar masses of ~2x10^11 M_Sun. Using the 3 mm and 1 mm bands at CARMA, we observe both the CO(1-0) and CO(3-2) transitions in these four galaxies in order to probe the excitation of the molecular gas. We report robust detections of both lines in three galaxies (and an upper limit on the fourth), with an average line ratio, r_31 = L'_CO(3-2) / L'_CO(1-0), of 0.46 \pm 0.07 (with systematic errors \lesssim 40%), which implies sub-thermal excitation of the CO(3-2) line. We conclude that the excitation of the gas in these massive, highly star-forming galaxies is consistent with normal star-forming galaxies such as local spirals, not starbursting systems like local ultra-luminous infrared galaxies. Since the EGNoG gas excitation sample galaxies are selected from the main sequence of star-forming galaxies, we suggest that this result is applicable to studies of main sequence galaxies at intermediate and high redshifts, supporting the assumptions made in studies that find molecular gas fractions in star forming galaxies at z~1-2 to be an order of magnitude larger than what is observed locally.Comment: Accepted for publication in the Astrophysical Journal, to appear January 2013; 18 pages, 10 figures, 6 table