304 research outputs found

    Garaselet – Biostratigraphical studies of human impact during different periods of settlement from the Mesolithic to Medieval times

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    lnvestigations in collaboration with Skellefteå Museum are in progress on material representing different periods of settlement at Garaselet on the Byskeälven river in Västerbotten, northern Sweden. Archaeological excavations south and north of the bays Garaselviken and Lappviken revealed the existence of a Mesolithic dwelling site dated c. 8000 B.P. The area was occupied also during the Neolithic, Bronze, Iron and Middle Ages. Studies of minerogenic and organogenic material from the excavation area, together with peat from the nearby mires and sediments from the bays, are being carried out using pollen and diatom analysis, organic carbon measurements, total composition analysis and radiocarbon dating. Preliminary results indicate that the human impact on vegetation and water is registered in the sediments, but was only of minor significance as compared with the natural changes of the palaeoecological and palaeohydrological environment. Pollen analysis and radiocarbon datings of peat samples from the mires show that the organic sedimentation started contemporary with the immigration of alder (Alnus) after 8700 B.P., just after the deglaciation of the area. The spread of spruce (Picea) took place after 3600 B.P

    The sustainability of communicative packaging concepts in the food supply chain. A case study: part 1. Life cycle assessment

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    Purpose In recent years, a new perspective for food packaging has emerged as a result of several issues like quality, safety, competitive prices or providing of useful information to consumers. This new perspective is called communicative packaging. Communicative packaging may influence consumers/companies on purchasing decisions. Since the environmental evaluation of such systems has not yet been performed, this paper is focused on the environmental evaluation of a flexible best-before-date (FBBD) communicative device on a packaging consumer unit and its implications on reducing environmental impacts related to fresh products. This consumer unit consists of a nanoclay-based polylactic acid tray filled with pork chops. Methods The environmental assessment of the consumer unit was made through life cycle assessment (LCA) using a cradle-to-gate approach. Environmental impacts were assessed according to the Eco-Indicator 99 v 2.1 methodology in Individualist (I) perspective. Results and discussion Several results were obtained from the LCA. With regard to environmental impacts of the FBBD, most of them were due to the paper substrate used for the manufacture of this communicative packaging concept as well as to the transports for delivering the components of the FBBD communicative device. On the other hand, when environmental impacts of packaging system with and without FBBD were compared, a large environmental load was detected for the system that has the communicative device affixed as a result of the higher weight of the package. However, the environmental load caused by the use of the FBBD was minimal in comparison with the total environmental load of the whole packaging system. On the contrary, the consumer unit that has the communicative device affixed showed less environmental burden than the consumer unit that has not affixed the device. This was due to the environmental benefits that the communicative device provides by reducing the amount of out-of-date packaged products at retailer outlets. Conclusions The use of a FBBD contributes to minimize environmental burdens related to the production, packaging and delivery of pork chops since it facilitates a dynamic control of out-of-date products even though the consumer unit with FBBD weighs 1 g more than the consumer unit that does not use the communicative device. Recommendations The results presented in this paper are estimated results of a specific case study for a prototype of communicative packaging device. Consequently, these results must be considered as a first approach according to future developments on communicative packaging

    Admission control for Web server systems - design and experimental evaluation

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    Correction due to finite speed of light in absolute gravimeters

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    Correction due to finite speed of light is among the most inconsistent ones in absolute gravimetry. Formulas reported by different authors yield corrections scattered up to 8 ÎĽ\muGal with no obvious reasons. The problem, though noted before, has never been studied, and nowadays the correction is rather postulated than rigorously proven. In this paper we make an attempt to revise the subject. Like other authors, we use physical models based on signal delays and the Doppler effect, however, in implementing the models we additionally introduce two scales of time associated with moving and resting reflectors, derive a set of rules to switch between the scales, and establish the equivalence of trajectory distortions as obtained from either time delay or distance progression. The obtained results enabled us to produce accurate correction formulas for different types of instruments, and to explain the differences in the results obtained by other authors. We found that the correction derived from the Doppler effect is accountable only for 23\frac23 of the total correction due to finite speed of light, if no signal delays are considered. Another major source of inconsistency was found in the tacit use of simplified trajectory models

    Extending an industrial root controller : implementation and applications of a fast open sensor interface

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    An overview is given of the design and implementation of a platform for fast external sensor integration in an industrial robot system called ABB S4CPlus. As an application and motivating example, the implementation of force-controlled grinding and deburring within the AUTOFETT-project is discussed. Experiences from industrial usage of the fully developed prototype confirms the appropriateness of the design choices, thus also confirming the fact that control and software need to be tightly integrated. The new sensor can be used for the prototyping and development of a wide variety of new application

    High tibial osteotomy in Sweden, 1998–2007: A population-based study of the use and rate of revision to knee arthroplasty

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    To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.Most studies on high tibial osteotomies (HTOs) have been hospital-based and have included a limited number of patients. We evaluated the use and outcome-expressed as rate of revision to knee arthroplasty-of HTO performed in Sweden with 9 million inhabitants, 1998-2007. 3, 161 HTO procedures on patients 30 years or older (69% men) who were operated on for knee osteoarthritis in Sweden, 1998-2007, were identified through the inpatient and outpatient care registers of the Swedish National Board of Health and Welfare. Pertinent data were verified through surgical records. Conversions of HTO to knee arthroplasty before 2010 were identified through the Swedish Knee Arthroplasty Register (SKAR). The 10-year survival was determined using revision to an arthroplasty as the endpoint. The number of HTOs decreased by one third between 1998 and 2007, from 388 operations a year to 257 a year. Most of the HTOs were performed with open wedge osteotomy using external fixation. The cumulative revision rate at 10 years was 30% (95% CI: 28-32). The risk of revision increased with increasing age and was higher in women than in men (RR = 1.3, CI: 1.1-1.5). If being without an artificial joint implant is considered to be beneficial, then HTO is an excellent alternative to knee arthroplasty in younger and/or physically active patients suffering from knee osteoarthritis.Swedish Research Council Swedish Rheumatism Association King Gustaf V 80-year Birthday Fund Faculty of Medicine, Lund University Region Skan

    A shelf-life study of silica- and carbon-based mesoporous materials

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    Mesoporous silica- and carbon-based materials, including bioactive glasses, have proven potential as components of medical devices and as drug carriers. From an application perspective, knowledge about the shelf-life stability of these materials under various conditions is vital. Here, mesoporous bioactive glasses (MBGs) synthesized by aerosol-assisted spray-drying and by a batch sol–gel method, mesoporous silicas of SBA-15 type, and mesoporous carbons CMK-1 and CMK-3 have been stored under varying conditions, e.g. at different temperature and relative humidity (RH), and in different storage vessels. The results show that the silica-based materials stored in Eppendorfs are sensitive to humidity. Spray dried MBGs decompose within 1 month at a RH >5%, whilst sol–gel MBGs are more stable up to a RH >60%. Changing the storage vessel to sealed glass flasks increases the MBGs lifetime significantly, with no degradation during 2 months of storage at a RH = 75%. SBA-15 stored in Eppendorfs are more stable compared to MBGs, and addition of F- ions added during the synthesis affects the material degradation rate. Mesoporous carbons are stable under all conditions for all time points. This systematic study clearly demonstrates the importance of storage conditions for mesoporous materials which is crucial knowledge for commercialization of these materials
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