159 research outputs found
Convergence aspects for sets of measures with divergences and boundary conditions
In this paper we study set convergence aspects for Banach spaces of
vector-valued measures with divergences (represented by measures or by
functions) and applications. We consider a form of normal trace
characterization to establish subspaces of measures that directionally vanish
in parts of the boundary, and present examples constructed with binary trees.
Subsequently we study convex sets with total variation bounds and their
convergence properties together with applications to the stability of
optimization problems
Tetrakis(N,N-diethylcarbamato)titanium(IV)
The mononuclear title compound, [Ti(C5H10NO2)4], is a rare example of an eight-coordinate TiIV compound in which all donor atoms are O atoms. The coordination geometry around TiIV is pseudo-dodecahedral and the O—C—O angles of the carbamate ligands are slightly compressed [range 115.3 (2)–116.7 (2)°], apparently on account of the high coordination number. One ethyl group is disordered over two positions; the site occupancy factors are 0.64 and 0.36
Recommended from our members
The Effect of Impurities on Permeance Through Chabazite Zeolite Membranes
Zeolite membranes selectively permeate gases based on differences in size, diffusivity, and loading. The chabazite zeolites SAPO-34 and SSZ-13 have 0.38-nm pores, which make them suitable for separating CO2 (0.33-nm kinetic diameter) from CH4 (0.38 nm) for natural gas purification. Natural gas also contains ethane, propane, butane, and higher hydrocarbon impurities that can adsorb in the membranes and affect their performance.
We studied the effect of small alkanes on H2/N2 separations in SAPO-34 by adding ethane, propane, or n-butane to the feed. Propane reduced the permeance of both gases, but it reduced the H2 permeance less than the N2 permeance, so that the selectivity increased from about 4 to about 9. n-Butane had a similar effect, but ethane caused no change in selectivity. Reduced H2 loading due to competitive adsorption would decrease H2/N2 selectivity if competitive adsorption were the dominant mechanism. Therefore, diffusion plays a significant role and the alkanes must have decreased N2 diffusivity more than H2 diffusivity.
We studied the effects of toluene, which is too large (0.59 nm) to diffuse into zeolite pores, on CO2 and N2 permeance through SAPO-34 membranes. When 0.65 mol% toluene was added to the feed, the CO2 permeance decreased by 45% and the N2 permeance decreased by 50% at 172-kPa pressure. At 10-kPa feed pressure, 8.5% toluene decreased CO2 permeance by 20%. Binary isotherm models predict that competitive adsorption between toluene and CO2 on the external surface significantly reduced the CO2 coverage, and thus the driving force for CO2 transport.
Finally, we measured the effect of C1 through C4 alkanes on CO2 permeance through SSZ-13 membranes. Propane and n-butane have kinetic diameters (0.43 nm) larger than the SSZ-13 pores, but they adsorb to high loadings in SSZ-13 crystals because these molecules are flexible. Methane decreased CO2 permeance by 5%, and ethane decreased CO2 permeance by 45% at the same concentration. Propane, however, only decreased CO2 permeance by 10%, and n-butane decreased the permeance by 15%. Apparently, the larger alkanes did not adsorb into the SSZ-13 pores, likely due to an altered external pore structure, and propane and n-butane only reduced CO2 permeance by adsorbing on the external surface.</p
Farming the Iveragh uplands: A tale of humans and nature
The rugged beauty of the Iveragh peninsula has fascinated many a passing visitor and never fails to make some of us linger or stay for good. For those who need proof of the area’s uniqueness, a variety of national and European designations provide ample attestation of the splendour of Iveragh’s scenery, the diversity of its landscape and its heritage. Being surrounded on three sides by the Atlantic, Iveragh is the largest and most geographically isolated peninsula in Ireland whose western extremity, the Great Skellig, forms the westernmost point of Europe. Despite its maritime location, Iveragh’s character is fundamentally determined by the mountains, valleys and streams that form the peninsula’s interior—the bequest of a landscape sculpted by ice thousands of years ago (Crowley and Sheehan, 2009). Distinctive mountain scene in the Bridia Valley, Glencar Perhaps most distinctive, however, are the extensive blanket bogs and upland heather moorlands that cover most of the peninsula and captivate the imagination with the wild and austere appeal of an area where life did not change much for man and beast until relatively recently. Having come into existence in the wake of woodland clearances, the cutting of vegetation for fuel and the harvesting of crops for food and fiber by Neolithic farmers in the first and second millennium BC, this unique cultural landscape continues to be managed by traditional farmers and their animals to the present day. The value of areas such as Iveragh as repositories of a unique flora and fauna has long been recognized, but they have entered a period of major transformation as the agricultural economy that lay behind them no longer exists (Webb, 1998). The single largest danger is that farming communities may not survive the present discussion of how competitive European agriculture should be, as under present market conditions they are unable to compete without fundamentally changing their way of farming (Luick, 1998). The last 10 years have seen a growing debate over the future of areas like the Iveragh peninsula that may be ‘marginal’ in agricultural terms, but that are quite essential to life in Europe as we know and cherish it. Upland farmed landscapes provide clean water, maintain a rich plant and animal life and help to keep families in regions that offer few alternative employment opportunities – at the same time as attracting millions of tourists each year. The Caragh in Glencar—one of Europe’s cleanest rivers. Such areas, also termed high nature value farmland, cover about 25% of all agricultural land in Ireland and include, besides Iveragh, other parts of Kerry, Connemara, Mayo, Donegal, the Comeraghs, Wicklow, the Burren and the offshore Islands. The farming systems of these areas are characterised by extensive mixed livestock grazing and little agro-chemical inputs combined with labour-intensive management practices. Without dedicated farmers and their families, the character of these areas would change completely leading to the disappearance of unique cultural landscapes with effects such as rural depopulation and the loss of local communities. Already farming systems have changed substantially with livestock being concentrated on better quality land while marginal areas are being abandoned. Along with this, there are changes in the animals being farmed. The traditional Scotch Blackface sheep are increasingly crossed with or replaced by lowland breeds to satisfy market demands for heavy lamb. This has led to a softening in sheep and the fear among farmers that the traditional grazers of the uplands may be extinct in years to come. Going, too, is the use of the native rustic Kerry cow that grazed the rough Farming the Iveragh Uplands grasses, bracken, gorse and soft rushes in the winter - growth that sheep cannot control. Unsurprisingly, this disruption over a relatively short time, in what was formerly a sustainable relationship between farming and nature, will have implications for the area’s flora and fauna. Some of the repercussions are obvious; others need to be researched in more depth if appropriate solutions are to be formulated. It is now a stated objective of EU environment and rural development policy to maintain and conserve traditional farming systems like the one practised on Iveragh. Beyond acknowledging the importance of traditional farming for nature conservation and local livelihoods, it is necessary to understand how such farming systems function and to determine how the inevitable process of change can be redirected to provide a way of life that is socially and economically rewarding for farm families while preserving the farming practices necessary for Iveragh’s unique landscape to persist into the future. In this light, University College Cork (UCC) in conjunction with the Environmental Research Institute (ERI) and funded by Science Foundation Ireland (SFI) initiated BioUp, a 3 year research programme to investigate the upland farming system and rich biodiversity associated with it. Managing rural change in the uplands calls for the active involvement of many stakeholders, including farmers and agricultural advisory groups, land owners, conservation groups, forestry, tourism, and local authorities. In the BioUp project, researchers and stakeholders worked closely together. It is hoped that this will help to obtain a better understanding of the social, economic and environmental challenges facing Iveragh and promote greater public appreciation of the indispensable contributions made by farm families to maintaining our unique heritage - a service that has gone unappreciated too long
Screening and Health Behaviors among Persons Diagnosed with Familial Adenomatous Polyposis and Their Relatives
Familial Adenomatous Polyposis (FAP) is a rare autosomal dominantly inherited colorectal cancer syndrome. Individuals with FAP often undergo colectomy and are recommended to follow several surveillance protocols. Biological relatives of persons with FAP may also be at risk and thus should undergo genetic counseling. Screening adherence, genetic testing, and other health behaviors among individuals with FAP and their relatives are not well characterized. We conducted a cross-sectional self-report survey with individuals who have FAP (n=35) and their biological relatives (n=15). Respondents were recruited through a cancer center registry for inherited colon cancers. Most relatives had undergone colon cancer screening; 40% had undergone genetic testing. One fifth of respondents with FAP had not undergone an upper endoscopy, contrary to usual recommendations. Cigarette smoking rates were above average and were higher among FAP respondents. Use of vitamin supplements was fairly common, more so among those with FAP. Although most people had been screened, there are areas for improvement, notably for upper endoscopy among individuals with FAP and genetic testing among family members. Several other health-risk behaviors and health concerns other than FAP were identified. Further research into factors contributing to screening rates and other health behaviors in this high-risk population is warranted
Challenges in the delivery of e-government through kiosks
Kiosks are increasingly being heralded as a technology through which governments, government departments and local authorities or municipalities can engage with citizens. In particular, they have attractions in their potential to bridge the digital divide. There is some evidence to suggest that the citizen uptake of kiosks and indeed other channels for e-government, such as web sites, is slow, although studies on the use of kiosks for health information provision offer some interesting perspectives on user behaviour with kiosk technology. This article argues that the delivery of e-government through kiosks presents a number of strategic challenges, which will need to be negotiated over the next few years in order that kiosk applications are successful in enhancing accessibility to and engagement with e-government. The article suggests that this involves consideration of: the applications to be delivered through a kiosk; one stop shop service and knowledge architectures; mechanisms for citizen identification; and, the integration of kiosks within the total interface between public bodies and their communities. The article concludes by outlining development and research agendas in each of these areas.</p
- …