Effect of Size on Electrical Performance

This paper was presented at IEEE International Symposium on Electrical Insulation, June 2006. ©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Digital Object Identifier: 10.1109/ELINSL.2006.1665249The electrical breakdown performance, either unaged or after ageing (laboratory or service), is often used as the basis for qualification of a device, design or material. Many of the features that affect these performance levels have been discussed in other documents; contaminants, propensity for water treeing, insulating and semiconducting materials. However the size of cable tested is rarely discussed. This is somewhat surprising as it has been long recognized that electrical failure is an extreme value (the Weibull distribution is a member of this family) or weakest link process. In extreme value processes the performance of the whole device is determined by the single "weakest link". Thus when more "weak links" are present the chance of failure is consequently higher: the measured performance depends on weak link concentration or size of the device. Additionally at some dimensions the thickness of the dielectric can influence the breakdown mechanism itself; especially if the thermal influences are present. This paper will attempt to discuss a number of these size related issues for both AC & impulse conditions; these will include: 1) the effect of the dielectric volume actual mechanism of failure, 2) prediction of performance on service length cables from short length laboratory tests. This has practical relevance on the selection of appropriate qualification levels which will have direct relevance to service performance, 3) the requirements for cable quality when increasing the size (thickness or length) installed

The Role of Degassing in XLPE Power Cable Manufacture

This paper appears in: Electrical Insulation Magazine, IEEE. ©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.This article focuses on a range of elements critical to this process; form the fundamental chemistry, through computational and measurement techniques to the solutions that are in use today. Degassing contributes greatly to the quality of power cables by improving the certainty in electrical testing and improving the dielectric properties. To ensure that the degassing process delivers the expected benefits, it is important to measure and model the process by which the crosslinking byproducts are desorbed from the cable polymers. Weight loss and HPLC have shown themselves to be the most effective and practical measurement techniques

Electromagnetic dissociation of relativistic 8^8B nuclei in nuclear track emulsion

Experimental data on fragmentation channels in peripheral interactions of $^8$B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process $^8$B $\to^7$Be + \emph{p} and to estimate its cross section. Events of $^{10}$C peripheral dissociation that were observed in the same exposure are described.Comment: 12 pages, 10 figures, 4 tables, Published in Phys.Atom.Nucl.72:690-701,200

Perception of differentiation cues by GATA factors in primitive endoderm lineage determination of mouse embryonic stem cells

AbstractThe formation of the primitive endoderm covering the inner cell mass of early mouse embryos can be simulated in vitro by the differentiation of mouse embryonic stem (ES) cells in culture following either aggregation of suspended cells or stimulation of cell monolayers with retinoic acid. The developmentally regulated transcription factors GATA-4 and GATA-6 have determining role in mouse extraembryonic endoderm development. We analyzed the in vitro differentiation of mouse embryonic stem cells deficient of GATA factors and conclude that GATA-4 is required for ES cells to perceive a cell positioning (cell aggregation) signal and GATA-6 is required to sense morphogenic (retinoic acid) signal. The collaboration between GATA-6 and GATA-4, or GATA-6 and GATA-5 which can substitute for GATA-4, is involved in the perception of differentiation cues by embryonic stem cells in their determination of endoderm lineage. This study indicates that the lineage differentiation of ES cells can be manipulated by the expression of GATA factors

Alteration of Differentiation Potentials by Modulating GATA Transcription Factors in Murine Embryonic Stem Cells

Background. Mouse embryonic stem (ES) cells can be differentiated in vitro by aggregation and/or retinoic acid (RA) treatment. The principal differentiation lineage in vitro is extraembryonic primitive endoderm. Dab2, Laminin, GATA4, GATA5, and GATA6 are expressed in embryonic primitive endoderm and play critical roles in its lineage commitment. Results. We found that in the absence of GATA4 or GATA5, RA-induced primitive endoderm differentiation of ES cells was reduced. GATA4 (−/−) ES cells express higher level of GATA5, GATA6, and hepatocyte nuclear factor 4 alpha marker of visceral endoderm lineage. GATA5 (−/−) ES cells express higher level of alpha fetoprotein marker of early liver development. GATA6 (−/−) ES cells express higher level of GATA5 as well as mesoderm and cardiomyocyte markers which are collagen III alpha-1 and tropomyosin1 alpha. Thus, deletion of GATA6 precluded endoderm differentiation but promoted mesoderm lineages. Conclusions. GATA4, GATA5, and GATA6 each convey a unique gene expression pattern and influences ES cell differentiation. We showed that ES cells can be directed to avoid differentiating into primitive endoderm and to adopt unique lineages in vitro by modulating GATA factors. The finding offers a potential approach to produce desirable cell types from ES cells, useful for regenerative cell therapy

Antimicrobial-resistant Enterobacterales colonization in people with HIV

Background: People with HIV (PWH) may be at increased risk for MDR Enterobacterales (MDR-E) infection or colonization, relative to individuals without HIV, due to a greater burden of comorbidities as well as HIV-related intestinal inflammation and microbiota alterations. Objectives: To characterize antibiotic susceptibility of enteric Enterobacterales and risk factors for antimicrobial-resistant bacterial infections in a sample of PWH attending routine clinic visits. Methods: Participants provided self-administered rectal swabs and completed questionnaires regarding healthcare, travel and occupational exposures for the prior 12 months. Rectal samples were processed to identify Enterobacterales species, and susceptibility testing was performed. Results: Among 82 participants, 110 Enterobacterales isolates were obtained. Non-susceptibility was common for penicillins, sulphonamides and first-generation cephalosporins. MDR-E was present in 20% of participants. HIV-related characteristics, including current or nadir CD4 cell count, viral suppression, or AIDS-defining clinical conditions, were not associated with MDR-E. Conclusions: MDR-E colonization is common in this population of PWH. Further research evaluating risk factors for MDR-E in PWH may inform infection prevention approaches to better protect at-risk populations from these difficult-to-treat infections

Initial State Dependence of the Breakup of Weakly Bound Carbon Isotopes

The one-neutron nuclear breakup from the Carbon isotopes $^{19}$C and $^{17}$C, is calculated as an example of application of the theory of transfer to the continuum reactions in the formulation which includes spin coupling. The effect of the energy sharing between the parallel and transverse neutron momentum distributions is taken into account thus resulting in a theory which is more general than sudden eikonal approaches. Both effects are necessary to understand properly the breakup from not too weakly bound $l_i>1$ orbitals. Breakup which leaves the core into an excited state below particle threshold is also considered. The core-target interaction is treated in the smooth cut-off approximation. By comparing to presently available experimental data we show how to make some hypothesis on the quantum numbers and occupancy of the neutron initial state. Possible ambiguities in the interpretation of inclusive cross sections are discussed.Comment: 22 RevTeX pages,3 ps figures. Phys. Rev. C, accepte

Curbside Recycling in the U.S.a.: Convenience and Mandatory Participation

This research examines the relationship between the success of a residential curbside recycling program (RCRP), measured as material recovery rate (MRR), and two program factors: (1) whether or not participation is mandated; and (2) convenience, measured by container provision, collection frequency and collection day relative to municipal solid waste collection day. Residential curbside recycling programs, with correct strategies and program design, can be an important part of solid waste management plans world-wide. While residential curbside recycling programs are growing in popularity, many basic design questions lie unanswered and successful program strategies are not always obvious. Data from 357 residential curbside recycling programs in the United States are used to test the hypotheses. Mandatory participation residential curbside recycling programs are seen to collect more material than voluntary participation residential curbside recycling programs. Container provision appears effective for voluntary, but not mandatory, residential curbside recycling programs. Increasing collection frequency appears to have a small positive effect on residential curbside recycling program success, while collection day has little effect on material recovery rate.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline