The INTELSAT Experience with Reconditioning of NiH2 Batteries

INTELSAT has been reconditioning NiH2 batteries since 1983 when the INTELSAT V F-6 geosynchronous communications satellite was launched. This was the first commercial use of NiH2 batteries. INTELSAT has continued this practice on all 46 NiH2 batteries it has operated in-orbit. The batteries are of several types including the classic INTELSAT cell, the HAC re-circulating design, and the Gates Mantech design. Reconditioning is performed twice each year, prior to the Eclipse Season. At this time Water Migration problems, if present, are dealt with. Temperature limits are imposed for the discharge and charge cycles as a safety precaution. In support of in-orbit operations, it is INTELSAT's practice to perform ground based life tests. In-orbit data and ground tests results are presented and the benefits of reconditioning noted

Ni-H2 cell characterization for INTELSAT programs

Various Ni/H2 cell designs manufactured for INTELSAT Programs during the past decade have been characterized electrically as a function of temperature. The resulting data for these INTELSAT V, VI, VII and VIIA cells are assembled in a manner which allows ready comparison of performance. Also included is a detailed description of each design

Balancing Safety and Developmental Potency: Assessing the Effect of Antioxidants and TET on Genomic Imprinting Stability.

Developmental potency represents the ability of undifferentiated cells to undergo transformation into differentiated cells, with specialised functions. The inner cell mass (ICM) of a blastocyst represents the most developmentally potent cells of the body. The ICM, along with the naïve embryonic stem cells derived from it, possess remarkably low levels of global DNA methylation; a trait that is intrinsic to their pluripotent phenotype and when artificially induced can help re-program differentiated cells back into a naïve state. Ten-eleven translocation (TET) enzymes actively remove DNA methylation in a Fe2+-dependent fashion. By assisting Fe2+ recycling, the antioxidant ascorbate has been shown to increase TET enzymatic activity and enhance reprogramming of differentiated cells to the naïve state. However, it is currently unclear if TET activation via ascorbate, or other antioxidants, can cause unwanted demethylation at imprint control regions; regulatory elements that control parent-of-origin specific gene expression. Loss of methylation at these regulatory groups results in the biallelic expression of the genes under their control. This phenomenon has been implicated in the formation of a range of cancers, as well as Beckwith-Wiedemann syndrome, a congenital overgrowth disorder. In this project, I aimed to test what effect the antioxidants ascorbate and hydroquinone have on the stability of imprint control regions through the activation of TET proteins, and in doing so, assess the safety and practicality of using naïve embryonic stem cells for future medical applications. I grew several naïve embryonic stem cell lines, including a TET triple knockout line with inducible TET expression, in varying concentrations of ascorbate or hydroquinone. Bisulfite amplicon sequencing and florescence activated cell sorting techniques were used to assess methylation patterns at the KCNQ1ot1 imprinted loci in the presence or absence of increased TET activity. While the study has been hampered by technical difficulties (i.e. clonal amplification was detected, particularly in TET knockout cell lines), I have shown that ascorbate causes significant demethylation of the KCNQ1ot1 imprinted region at 25 ng/μL of ascorbate. While other concentrations, (12.5 ng/μL and 50 ng/μL of ascorbate) were not statistically significant there appeared to be a trend of decreasing methylation which may have become more obvious had the cells been cultured with ascorbate for longer. Interestingly this effect was not seen at 100 ng/μL of ascorbate, indicating there is an optimal concentration range for TET-induced demethylation at the KCNQ1ot1 locus. In contrast, hydroquinone had no significant effect. Ultimately, these results add to the current literature describing the effects of different culture media constituents on naïve embryonic stem cells. This may allow for the rational design of culture media that can improve both the efficiency and safety of naïve embryonic stem cells and embryos used in regenerative medicine, mammalian transgenics and IVF

Tracking a northern fulmar from a Scottish nesting site to the Charlie-Gibbs Fracture Zone : Evidence of linkage between coastal breeding seabirds and Mid-Atlantic Ridge feeding sites

Peer reviewedPublisher PD

Reliability of perceptions of voice quality: evidence from a problem asthma clinic population

<p>Introduction: Methods of perceptual voice evaluation have yet to achieve satisfactory consistency; complete acceptance of a recognised clinical protocol is still some way off.</p> <p>Materials and methods: Three speech and language therapists rated the voices of 43 patients attending the problem asthma clinic of a teaching hospital, according to the grade-roughness-breathiness-asthenicity-strain (GRBAS) scale and other perceptual categories.</p> <p>Results and analysis: Use of the GRBAS scale achieved only a 64.7 per cent inter-rater reliability and a 69.6 per cent intra-rater reliability for the grade component. One rater achieved a higher degree of consistency. Improved concordance on the GRBAS scale was observed for subjects with laryngeal abnormalities. Raters failed to reach any useful level of agreement in the other categories employed, except for perceived gender.</p> <p>Discussion: These results should sound a note of caution regarding routine adoption of the GRBAS scale for characterising voice quality for clinical purposes. The importance of training and the use of perceptual anchors for reliable perceptual rating need to be further investigated.</p&gt

Dynamic Reliability Assessment of PEM Fuel Cell Systems

In this paper, a novel model for the dynamic reliability analysis of a polymer electrolyte membrane fuel cell system is developed to account for multi-state dynamics and ageing. The modelling approach involves the combination of physical and stochastic sub-models with shared variables. The physical model consists of deterministic calculations of the system state described by variables such as temperature, pressure, mass flow rates and voltage output. Additionally, estimated component degradation rates are also taken into account. The non-deterministic model is implemented with stochastic Petri nets which model the failures of the balance of plant components within the fuel cell system. Using this approach, the effects of the operating conditions on the reliability of the system were investigated. Monte Carlo simulations of the process highlighted a clear influence of both purging and load cycles on the longevity of the fuel cell system

Intractable policy failure: the case of bovine TB and badgers

The failure to eliminate bovine TB from the English and Welsh cattle herd represents a long-term intractable policy failure. Cattle-to-cattle transmission of the disease has been underemphasised in the debate compared with transmission from badgers despite a contested evidence base. Archival evidence shows that mythical constructions of the badger have shaped the policy debate. Relevant evidence was incomplete and contested; alternative framings of the policy problem were polarised and difficult to reconcile; and this rendered normal techniques of stakeholder management through co-option and mediation of little assistance

Starling foraging success in relation to agricultural land-use

Changes in agricultural land-use have been suggested to contribute to the decline of several bird species through negative effects on their food supply during breeding. One important change in land-Use has been loss of pastures, especially permanent pastures. In this study we investigated how different forms of agricultural land-use affected foraging success or a declining bird species, the European starling Sturnus vulgaris. We let caged starlings forage in different forms of agricultural fields and determined time spent foraging and foraging success, The starlings' activity level (time spent actively foraging) as well as the number of prey caught per time unit was strongly related to the abundance of prey in soil samples. Also the body mass change during the experiment was positively related to activity level and prey capture rate, We found consistent differences in foraging variables between habitats. In spring sown grain starlings were least active and found fewer prey items at a lower rate than in any other habitat. The other three habitats differed less, but in general mowed hay fields appeared slightly more valuable than the cultivated and natural pastures. We did not find any differences between natural and cultivated pastures in foraging variables. Thus, starling foraging success is higher in grass-covered fields than in cultivated fields, but the management of the grass-covered fields mattered less. The results are consistent with starlings having higher population densities and breeding success in areas with higher availability of pasture. We suggest that the physical structure of the habitat (sward height) and Moisture may be additional variables that need to be taken into account to explain starling breeding density and success in the agricultural landscape

Societal and cultural research opportunities at a deep UK geological carbon dioxide storage research facility : results from a social science ‘sandpit’ discussion

This report describes the outcomes of a sandpit activity in December 2021, and initial follow up discussions, designed to bring together academics from across and beyond the UK, as well as members of public sector organisations. The intended outcomes were to discuss and develop societal and cultural research opportunities as part of a scoping study for a UK CO2 storage research facility. These outcomes are a research community view that inform the questions and knowledge gaps that a research facility would address. The sandpit is the first of many activities that will enable us to build an evidence base to demonstrate how a research facility would benefit from societal and cultural research and unlock new research themes. In particular, how the identified research themes support the UK’s transition to a sustainable future. The following themes were identified: • the role of culture and heritage in shaping community views and energy literacy; • placed-based and participatory research and the links between people’s sense of place and new energy infrastructure activities; • the value of tacit knowledge and collective memory to support co-design and community agency; • energy justice in support of a just and inclusive energy transition; • good governance to support ethical and responsible innovation; • benefits and risks, inclusive knowledge production and community involvement in decision making; • social conflict, controversies and trust in ‘energy actors’; • existing CO2 storage narratives and how these might be changed; • use of creative arts-based approaches to deepen community engagement; • the CO2 storage research facility as a ‘public lab’ to support a range of engagement approaches. Recommendations are made in this report concerning the development a new programme of integrated, interdisciplinary and inclusive research, based on priority research themes, in a timely fashion to ensure maximum benefit and impact. We also recommend that a cross-research council funding strategy is developed in support of this research. We suggest that developing such an integrated programme would: enable community agency in the development and co-design of a CO2 storage research facility; encourage dialogue and investment in wider carbon mitigation strategies and support localised behaviour change; embed an understanding of the role CO2 storage could play in the energy transition; and enable positive, transparent and inclusive energy and climate policy development both locally and nationally

Ecology good, aut-ecology better; Improving the sustainability of designed plantings

© 2015 European Council of Landscape Architecture Schools (ECLAS). This paper explores how contemporary ecological science, and aut-ecology in particular, can improve the sustainability of designed vegetation. It is proposed that ecological understanding can be applied to design at three levels: 1) as representation, 2) as process, and 3) as aut-ecology, representing a gradient from the least to the most profound. Key ecological interactions that determine the success of designed plantings are explored via a review of relevant ecological research, challenging some widely held but unhelpful constructs about how both semi-natural and designed vegetation actually function. The paper concludes that there are real benefits to integrating aut-ecological understanding in the design of vegetation at all scales but that this will require ecological theory to be taught as a design toolkit rather than largely as descriptive knowledge