444 research outputs found

    Capacity recovery after storage negatively precharged nickel hydrogen cells

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    Tests were conducted to investigate the recovery of capacity lost during open circuit storage of negatively precharged nickel hydrogen batteries. Four Eagle Picher RNH-90-3 cells were used in the tests. Recovery procedures and test results are presented in outline and graphic form

    Capacity loss on storage and possible capacity recovery for HST nickel-hydrogen cells

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    Negatively precharged nickel hydrogen cells will experience a useable capacity loss during extended open circuit storage periods. Some of the lost capacity can be recovered through cycling. Capacity recovery through cycling can be enhanced by cycling at high depths of discharge (DOD). The most timely procedure for recovering the faded capacity is to charge the cell fully and allow the cell to sit open-circuit at room temperature. This procedure seems to be effective in part because of the enlarged structure of the active materials. The compounds that formed during storage at the low electrode potentials can more easily dissolve and redistribute. All of the original capacity cannot be recovered because the lattice structure of the active material is irreversibly altered during storage. The recommendation is to use positively precharged cells activated with 26 percent KOH if possible. In aerospace applications, the benefits of negative precharge are offset by the possibility of delays and storage periods

    Prediction Markets: Alternative Mechanisms for Complex Environments with Few Traders

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    Double auction prediction markets have proven successful in large-scale applications such as elections and sporting events. Consequently, several large corporations have adopted these markets for smaller-scale internal applications where information may be complex and the number of traders is small. Using laboratory experiments, we test the performance of the double auction in complex environments with few traders and compare it to three alternative mechanisms. When information is complex we find that an iterated poll (or Delphi method) outperforms the double auction mechanism. We present five behavioral observations that may explain why the poll performs better in these settings

    Reactions to Value Pricing by Different Suburban Population Groups

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    Value pricing strategies are beginning to be considered for future improvements in suburban areas that currently do not experience significant congestion but are expected to become congested in the future. This is a significant departure from implementing these strategies in congested urban areas as is commonly done now. Therefore, traveler reaction in these suburban areas is unknown. To plan and design value pricing projects most effectively, it will be necessary to gain an understanding of suburban travelers' potential reaction to value pricing. Responses to a survey of travelers using the eastern and western segments of Interstate 10 (I-10) outside of San Antonio were used to study differences in response to value pricing by suburban population groups. These surveys collected information on travelers' socioeconomic and trip characteristics as well as their attitudes towards value pricing in the form of potential Express Toll Lanes (ETLS). Stated preference scenarios presented to survey respondents were used to develop mode choice models. These models were used to determine characteristics that may impact the decision to choose to travel on the general purpose lanes (GPLs) or the ETLs. This research suggests that the implementation of value pricing strategies on suburban corridors may pose a challenge from a policy standpoint. The populations using these corridors appear to be more varied in their responses toward value pricing than populations using congested urban corridors. Overall, it was found that the majority of travelers on I-10E and I-10W are not favorable to the implementation of value pricing for the future expansion of these corridors. However, I-10W travelers seem to be more willing to pay for travel time savings. This is likely due to the fact that travelers on I-10W earn higher average incomes, are more likely to use I-10W on a regular basis for commute purposes, and are more often exposed to some traffic congestion. Conversely, travelers on I-10E are more likely to use I-10E less frequently for non-commute trips, travel longer distances, and probably do not have an intuitive sense of the value they would place on travel time savings since they do not regularly experience congestion

    An Index to Assess the Sensitivity of Gulf of Mexico Species to Changes in Estuarine Salinity Regimes

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    An index of biological sensitivity to changes in freshwater inflow was developed for 44 species in 22 Gulf of Mexico estuaries for adult and juvenile life stages of fishes and macroinvertebrates. The BioSalinity Index (BSI) provides an innovative approach to quantify estuary-specific sensitivity of organisms to changes in estuarine salinity regimes based upon our knowledge of species salinity habitat preferences, the availability of this preferred habitat, and the relative abundance and distribution of species in time and space. We found that a significant difference exists between adult and juvenile life stage sensitivity, with juveniles exhibiting a lower sensitivity to salinity changes than adults, and that a considerable disparity exists in species-specific sensitivities among Gulf estuaries. Likewise, when the full complement of 44 species-level BSIs are averaged, marked differences in assemblage-wide sensitivity are evident across estuaries. The availability of preferred salinity habitat had a greater influence on the BSI for estuarine species than did their relative abundance and temporal distribution. The BSI was applied by members of a 1995 Gulf of Mexico freshwater inflow workshop to identify a subset of estuaries which appear more sensitive to freshwater inflow changes and are candidates for further study

    MG-132, an inhibitor of proteasomes and calpains, induced inhibition of oocyte maturation and aneuploidy in mouse oocytes

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    BACKGROUND: Although chromosome missegregation during oocyte maturation (OM) is a significant contributor to human morbidity and mortality, very little is known about the causes and mechanisms of aneuploidy. Several investigators have proposed that temporal perturbations during OM predispose oocytes to aberrant chromosome segregation. One approach for testing this proposal is to temporarily inhibit the activity of protein proteolysis during OM. We used the reversible proteasome inhibitor MG-132 to transiently perturb the temporal sequence of events during OM and subsequently analyzed mouse metaphase II (MII) for cytogenetic abnormalities. The transient inhibition of proteasome activity by MG-132 resulted in elevated levels of oocytes containing extra chromatids and chromosomes. RESULTS: The transient inhibition of proteasome-mediated proteolysis during OM by MG-132 resulted in dose-response delays during OM and elevated levels of aneuploid MII oocytes. Oocytes exposed in vitro to MG-132 exhibited greater delays during metaphase I (MI) as demonstrated by significantly (p < 0.01) higher levels of MI arrested oocytes and lower frequencies of premature sister chromatid separation in MII oocytes. Furthermore, the proportions of MII oocytes containing single chromatids and extra chromosomes significantly (p < 0.01) increased with MG-132 dosage. CONCLUSIONS: These data suggest that the MG-132-induced transient delay of proteasomal activity during mouse OM in vitro predisposed oocytes to abnormal chromosome segregation. Although these findings support a relationship between disturbed proteasomal activity and chromosome segregation, considerable additional data are needed to further investigate the roles of proteasome-mediated proteolysis and other potential molecular mechanisms on chromosome segregation during OM

    When Reds are Redder and Blues are Bluer: Party Competition, Party Polarization, and the Changing Demand for Lobbying in the American States

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    Interest system density influences internal dynamics within interest organizations, how they lobby, and policy conditions. But how do political conditions influence interest system density? How does politics create demand for interest representation? We examine these questions by assessing how legislative party competition and ideological distance between parties in state legislatures affect the number of lobby groups. After stating our theoretical expectations, we examine 1997 and 2007 data on legislative competition and party polarization to assess their influence on system density. We find mixed results: Whereas politics slightly influenced the structuring of nonprofit interest communities, they seem to have not affected the structuring of for-profit interest communities or interest communities as a whole

    The relationship between ventilatory threshold and repeated-sprint ability in competitive male ice hockey players

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    Background/objective The relationship between ventilatory threshold (VT1, VT2) and repeated-sprint ability (RSA) in competitive male ice hockey players was investigated. Methods Forty-three male ice hockey players aged 18–23 years competing in NCAA Division I, NCAA Division III, and Junior A level participated. Participants performed an incremental graded exercise test on a skate treadmill to determine V˙ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3eV˙O2peak, VT1, and VT2 using MedGraphics Breezesuit™ software (v-slope). Participants performed an on-ice repeated shift (RSA) test consisting of 8-maximal skating bouts, lasting approximately 25 s and interspersed with 90 s of passive recovery, to determine first gate, second gate, and total sprint decrement (%dec). Pearson product-moment correlations and multiple regressions were used to assess relationships between ventilatory threshold variables (VT1, VT2, Stage at VT1, and Stage at VT2) and RSA (first gate, second gate, and total course decrement). Results Stage at VT2 was the only variable substantially correlated with first gate (r = −0.35; P \u3c 0.05), second gate (r = −0.58; P \u3c 0.001) and total course decrement (r = −0.42; P \u3c 0.05). Conclusion The results of this study demonstrated that VT is substantially associated with RSA, and VT2 is more strongly correlated with RSA than V˙ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3eV˙O2peak. This study suggests that longer duration high-intensity interval training at intensities that increase workrate at VT2 may lead to possible improvements in RSA

    Parental notification policies, practices, and impacts in 2000 and 2002

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    Since the enactment of the Drug Free Schools and Communities Act Amendments of 1989, there have been several additional attempts by Congress to address the problem of alcohol abuse on college campuses. In 1 990, Congress passed the Student Right-to-Know and Campus Security Act containing a provision requiring institutions to notify students of the number of arrests for liquor law violations. In the 1998 Higher Education Amendments (HEA), Congress proposed a set of initiatives institutions should take to change the culture of alcohol consumption on college campuses. Entitled The Collegiate Initiative to Reduce Binge Drinking and Illegal Consumption, this particular section of HEA was not law, but only a resolution expressing the sense of Congress. HEA also renamed the Campus Security Act as the Jeanne Clery Disclosure of Campus Security Policy and Campus Crime Statistics Act and expanded the data regarding alcohol violations that institutions were required to report. Prior to the 1998 Amendments, institutions were mandated only to keep and distribute data on the number of arrests for alcohol violations. HEA broadened that requirement to include persons referred for campus disciplinary action for liquor law violations. Finally, HEA included changes to the Family Educational Rights and Privacy Act of 1974 (FERPA) to allow institutions to notify the parents of students under the age of 21, if those students violated Federal, State, or local laws or any rule or policy of the institution governing the use or possession of alcohol. This is now commonly referred to as parental notification
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