The JPL/NASA/TAMU nickel-cadmium battery model development status

A discussion of the development of a fundamental cell model is presented in vugraph format. The nickel oxide layer is described in terms of the electronic conductivity of the oxide layer and proton diffusion through the oxide layer. The kinetic and conductivity expressions for the cadmium electrode were improved. The development process yielded performance predictions that are significantly improved

Improved Control of Charging Voltage for Li-Ion Battery

The protocol for charging a lithium-ion battery would be modified, according to a proposal, to compensate for the internal voltage drop (charging current internal resistance of the battery). The essence of the modification is to provide for measurement of the internal voltage drop and to increase the terminal-voltage setting by the amount of the internal voltage drop. Ordinarily, a lithium-ion battery is charged at constant current until its terminal voltage attains a set value equal to the nominal full-charge potential. The set value is chosen carefully so as not to exceed the lithium-plating potential, because plated lithium in metallic form constitutes a hazard. When the battery is charged at low temperature, the internal voltage drop is considerable because the electrical conductivity of the battery electrolyte is low at low temperature. Charging the battery at high current at any temperature also gives rise to a high internal voltage drop. In some cases, the internal voltage drop can be as high as 1 volt per cell. Because the voltage available for charging is less than the terminal voltage by the amount of the internal voltage drop, the battery is not fully charged (see figure), even when the terminal voltage reaches the set value. In the modified protocol, the charging current would be periodically interrupted so that the zero-current battery-terminal voltage indicative of the state of charge could be measured. The terminal voltage would also be measured at full charging current. The difference between the full-current and zero-current voltages would equal the internal voltage drop. The set value of terminal voltage would then be increased beyond the nominal full-charge potential by the amount of the internal voltage drop. This adjustment would be performed repeatedly, in real time, so that the voltage setting would track variations in the internal voltage drop to afford full charge without risk of lithium plating. If the charging current and voltage settings were controlled by a computer, then this method of charge control could readily be implemented in software

Prevalence of Defecation Disorders and their Symptoms is Comparable in Children and Young Adults:Cross-Sectional Study

Purpose: We aimed to compare the prevalence rates and associated symptoms of constipation and fecal incontinence in children and young adults and evaluate how these patient groups cope with these disorders. Methods: A cross-sectional study was performed in which 212 children (8-17 years) and 149 young adults (18-29 years) from the general Dutch population completed a questionnaire about defecation disorders. Results: Constipation occurred in 15.6% of children and 22.8% of young adults (p=0.55), while the prevalence of fecal incontinence was comparable between groups (7%, p=0.91). The symptoms associated with constipation occurred as often in children as in young adults, while most fecal incontinence symptoms occurred more often in young adults. Approximately 43% of children had constipation for more than 5 years, while 26% of young adults experienced constipation since childhood. Only 27% of constipated children and 21% of constipated young adults received treatment (mostly laxatives). For fecal incontinence, 13% of children and 36% of young adults received treatment (mostly antidiarrheal medications or incontinence pads). Conclusion: In contrast to the general belief, the prevalence of defecation disorders and associated symptoms seem to be comparable in children and young adults. Only a few people with defecation disorders receive adequate treatment

Electrical characterization of the Magellan batteries after storage

Two 22 cell batteries designed by Martin Marietta were tested. The batteries were rated at 26.5 Amp-Hr. The battery design is characterized by the following: Gates Aerospace 42B030AB15, 11 pos/12 neg, Pellon 2536 separator, passivated pos/teflonated neg. The tests can be summarized as follows: (1) no noticeable capacity loss after storage period; and (2) batteries exhibited larger non-uniformity of cell voltages during constant current charge

Dutch Adolescents’ Everyday Expressions of Sexual Behavior Trajectories Over a 2-Year Period:A Mixed-Methods Study

Using an extended definition of sexuality, this mixed-methods study builds on existing research into adolescents' emergent sexual development by longitudinally examining adolescents' sexual behavior trajectories (i.e., from less to more intimate sexual behavior). Over a 2-year period, 45 adolescents (M age = 15.9 years) reported on their sexual behavior using questionnaires and on their everyday expressions of sexuality in the form of semi-structured diaries. Cluster analysis using the questionnaire data identified three sexual behavior trajectories: a non-sexually active trajectory (meaning no or minor sexual behavior) (n = 29), a gradually sexually active trajectory (meaning step-by-step sexual behavior development) (n = 12), and a fast sexually active trajectory (meaning rapid sexual behavior development) (n = 4). Qualitative analysis using diaries revealed the following themes: romantic versus sex-related topics, desires, uncertainties, and references to the social context. In general, all adolescents reported more about romantic aspects of sexuality (than about sexual acts) in the diaries, regardless of their sexual behavior trajectory. Sexually active adolescents (i.e., gradual and fast) were more concerned with sexuality in their diaries, especially more with the physical aspects of sexuality, than non-active adolescents. Gradual adolescents experienced more desires about physical sexual contact and reported fewer references to their social network than non-active and fast adolescents. The findings suggest that sexual education that discusses the internal experiences of sexuality, such as feelings and thoughts, particularly the romantic aspects, may help adolescents process their preferences for different sexual and romantic acts and may contribute to healthy sexual development

Effect of Proton Diffusion, Electron Conductivity, and Charge-Transfer Resistance on Nickel Hydroxide Discharge Curves

Constant-current discharge curves for the nickel hydroxide electrode are simulated assuming resistances due to diffusion of protons and conduction of electrons through the nickel hydroxide film, and charge-transfer resistance at the film/electrolyte interface contribute to the polarization losses of the electrode. Good qualitative agreement is observed between the model predictions and experimental discharge curves. The results suggest that polarization losses due to diffusional limitations of protons is a critical factor in determining the characteristics of the discharge curve. Ohmic resistance has a significant effect on the discharge curves at the end of discharge, and charge-transfer resistance is a minor contributor to the polarization losses. These findings indicate that accurately measuring the diffusion coefficient of protons, the thickness of the hydroxide film, the initial state-of-charge, and the electronic conductivity as a function of state-of-charge towards the end of discharge are critical in accurately predicting the discharge characteristics of nickel hydroxide. Physical constants which were shown to have minor influence on the discharge curves are the film conductivity at the beginning of discharge, and the exchange current density and cathodic transfer coefficient for the reaction. The time-dependent, one-dimensional diffusion equation has been solved analytically which should provide a computationally efficient means of accounting for proton diffusion and variable electronic conductivity in a macrohomogeneous battery model without sacrificing accuracy

Young people's everyday romance and sexual experiences in relation to sex-related conversations with parents:a diary study in the Netherlands

This study builds on existing research into how young people's emergent sexual development is connected to parent-child sex-related communication through avoidance vs. disclosure. Over the course of one year, a total of 21 young people (age range 12-17.5) reported in longitudinal qualitative diaries their (1) everyday sexual experiences and (2) sex-related conversations with their parents. Using a mixed-methods approach, findings show that less sexually experienced participants reported greater avoidance of parent-child sex-related conversations than more experienced participants. The sex-related conversations of more experienced participants mainly concerned overt experiences in the form of everyday issues with their romantic partner, while the conversations of less experienced participants were characterised by more covert experiences such as opinions about romantic relationships in general. These results suggest that the degree to which young people feel comfortable talking about sexuality with their parents partly depends on when the conversation takes place during a young person's romantic and sexual development

Effect of dexamethasone on fetal hepatic glutamine-glutamate exchange

Intravenous infusion of dexamethasone (Dex) in the fetal lamb causes a two- to threefold increase in plasma glutamine and other glucogenic amino acids and a decrease of plasma glutamate to approximately one-third of normal. To explore the underlying mechanisms, hepatic amino acid uptake and conversion of L-[1-(13)C]glutamine to L-[1-(13)C]glutamate and (13)CO(2) were measured in six sheep fetuses before and in the last 2 h of a 26-h Dex infusion. Dex decreased hepatic glutamine and alanine uptakes (P < 0.01) and hepatic glutamate output (P < 0.001). Hepatic outputs of the glutamate (R(Glu,Gln)) and CO(2) formed from plasma glutamine decreased to 21 (P < 0.001) and 53% (P = 0.009) of control, respectively. R(Glu,Gln), expressed as a fraction of both outputs, decreased (P < 0.001) from 0.36 +/- 0.02 to 0.18 +/- 0.04. Hepatic glucose output remained virtually zero throughout the experiment. We conclude that Dex decreases fetal hepatic glutamate output by increasing the routing of glutamate carbon into the citric acid cycle and by decreasing the hepatic uptake of glucogenic amino acids

Relationship of fetal alanine uptake and placental alanine metabolism to maternal plasma alanine concentration

Uterine and umbilical uptakes of alanine (Ala) were measured in 10 ewes before (control) and during intravenous infusion of Ala, which increased maternal arterial Ala concentration from 115 +/- 14 to 629 +/- 78 microM (P < 0.001). In 8 of these ewes, placental Ala fluxes were traced by constant intravenous infusion of L-[3,3,3-2H3]Ala in the mother and L-[1-13C]Ala in the fetus. Rates are reported as micromoles per minute per kilogram fetus. Ala infusion increased uterine uptake (2.5 +/- 0.6 to 15.6 +/- 3.1, P < 0.001), umbilical uptake (3.1 +/- 0.5 to 6.9 +/- 0.8, P < 0.001), and net uteroplacental utilization (-0.7 +/- 0.8 to 8.6 +/- 2.7, P < 0.01) of Ala. Control Ala flux to fetus from mother (Rf,m) was much less than the Ala flux to fetus from placenta (Rf,p) (0.17 +/- 0.04 vs. 5. 0 +/- 0.6). Two additional studies utilizing L-[U-13C]Ala as the maternal tracer confirmed the small relative contribution of Rf,m to Rf,p. During maternal Ala infusion, Rf,m increased significantly (P < 0.02) but remained a small fraction of Rf,p (0.71 +/- 0.2 vs. 7.3 +/- 1.3). We conclude that maternal Ala entering the placenta is metabolized and exchanged for placental Ala, so that most of the Ala delivered to the fetus is produced within the placenta. An increase in maternal Ala concentration increases placental Ala utilization and the fetal uptake of both maternal and placental Ala