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Luleå tekniska universitet Övrigt
We conducted a usability study comparing three different browser alternatives (iconic, zoom-and-pan, and fisheye) for an electronic bulletin board containing thumbnails of notes. The iconic browser behaves in the manner of a standard windowing system. The zoom-and-pan browser allows the user to pan over a note and zoom to a readable size. The fisheye browser was an implementation of the bifocal view. We conducted an experiment where 21 subjects performed browsing tasks with each browser. We found that users performed best with the iconic browser and that young people (20-25) were significantly faster than older (31-53).
953-96769-9-1 / Link / Hedman , Anna / 2004

Luleå tekniska universitet Övrigt
A small desk survey was conducted in the spring of 2004 to get an overview on the development of waste research. The survey targeted the last 10 years of waste research at Swedish academic institutions trying to identify the total amount of research and trends over time with regard to issues, volume and distribution over academic disciplines. In the survey, only the theses written at major Swedish universities were considered. All post-graduate theses from major Swedish universities were reviewed. Data were obtained from the homepages and search engines of the various libraries as of May 13 2004. Altogether 90 theses were identified from nine universities, i.e., an average of 1 thesis per University per year. The results of the survey indicate that: (1) the academic waste research is very small in comparison to the R&D performed by the industry; there seems to be a lack of interaction between industry and academia; (2) waste research is slowly getting into established academic environments and gains in quantity and diversion over time; (3) in addition to being driven by environmental protection legislation, there also seems to be emerging more industry interest from a production perspective.
N/A / Link / Lagerkvist , Anders / 2006

Luleå tekniska universitet Övrigt
Glulam members often become large in cross section where heavy loads should be carried. In some applications this may cause problems if limitations on height are posed. A possible solution is to reinforce the member by e.g. bonding fibre reinforced polymer (FRP) on the beams or between the glulam lamellas. The aim of this paper is to investigate the possibility of strengthening glulam beams by the use of pultruded rectangular carbon fibre rods and to establish the anchoring length for this system. Tests were performed in three different series completed by a reference series, 10 specimens altogether. All tests were performed as short-term experiments in four-point bending. The experimental results were compared to analytical models in several aspects. The overall capacity of the beam was established using an analogy with concrete beams. Special attention was made to establishing the anchoring length of the reinforcement bar, since this is governing to avoid premature failures. The anchorage length was tested and an analytical model established. The agreement between the analytical critical anchoring length and the test result was satisfactory. The proposed reinforcement method increased the short-term flexural load-carrying capacity by 49-63% on average.
N/A / Link / Johnsson , Helena / 2007

Luleå tekniska universitet Övrigt
Vast tonnages of solid-liquid mixtures are pumped every year in dredging operations, mining and waste-disposal applications. Most of these systems are centrifugal pumps, and the resolution of problems encountered in slurry pumping requires both detailed scientific knowledge and judgment derived from practical experience. For many years the combination of up-to-date analysis and hands-on experimentation has been provided to interested engineers in a short course based at the GIW Hydraulic Laboratory. The lecturers in this course, who represent a broad background of international expertise, have prepared this widely-recognized text, Slurry Transport Using Centrifugal Pumps, Third Edition. This unique text is logically divided into two sections: the first part of the book concentrates on the behaviors of various sorts of slurry flow, and the second part deals with the behavior of centrifugal pumps handling slurries, and with how pumps and pipelines interact as a system.
0-387-23262-1 / Link / Wilson , Kenneth C. / 2006

This study analysed road runoff in northern Sweden with respect to the concentrations of and the loads of particles in different size fractions (4-6, 6-9, 9-15, 15-25, 25-40, and 40-120 μm) between a snowmelt period and a rainfall period, as well as during events within each period. There are also comparisons of the transport of different particle sizes between the two periods and during events within the periods and discussions on how different metals are associated with the varying particle sizes. The results showed, on average, eight times higher concentrations and five times higher loads of particles during the snowmelt period compared to the rain period for all particle size intervals. Using a t-test with 14 degrees of freedom, at a 90% and 95% confidence level, the mean- and the event mean concentrations of all particle size intervals were higher during the melt period compared to the rain period. Also, the particle concentrations for both periods decrease as the particle size increases. During the snowmelt and rainfall period, important factors influencing the concentrations and loads were the availability of material, the intensity of the lateral flow for the transport of the particles, and, additionally, for the rain period, the length of dry weather in between events. During the melt period, investigated particle sizes and TSS were highly correlated with total concentrations of Cd, Cu, Ni, Pb, and Zn. During the rain period, the correlations between total metal concentrations and the different particle sizes were not as significant.
N/A / Link / Westerlund , Camilla / 2006

Luleå tekniska universitet Övrigt
When measuring the capability of a manufacturing process some form of process capability index is often used. To assess the capability, using a random sample, confidence intervals or hypothesis tests on the index are frequently used. Here, an alternative approach is presented. A process is usually defined to be capable if the capability index exceeds a stated threshold value, e.g. Cpm > 4/3. This inequality can be expressed graphically as a region in the plane defined by the process parameters (µ, σ). This graphical region, or safety region, similar to a confidence region for ((µ, σ).  can be plotted to test for capability. Under the assumption of normality a circular safety region for the capability index Cpm is constructed that can be used to draw conclusions about the capability at a given significance level. This simple graphical approach is helpful when trying to understand if it is the variability, the deviation from target or both that need to be reduced to improve the capability. Using circular regions several characteristics can be monitored in the same plot.
N/A / Link / Vännman , Kerstin / 2005

HS-DSCH is a high-speed shared radio channel extension for WCDMA which is used for cellular mobile telephony. The algorithm for distributing the channel resources together with the characteristics of the radio medium result in delay variations. The TCP minimum retransmission timeout interval has effectively alleviated delay variations in its range from deteriorating TCP performance. But recently, this bound has been shortened in modern widely spread TCP implementations. The aim of our study is to find out how a shorter minimum retransmission timeout affects TCP performance over HS-DSCH. We have implemented a model of HS-DSCH in the network simulator ns-2. Our simulations cover a wide range of different minimum retransmission timeout settings and loads, two types of schedulers (Round-Robin and Signalto-Interference-Ratio (SIR) scheduling) and two versions of TCP (SACK and NewReno). Our results show that the number of spurious timeouts increase with the load. The SIR scheduler causes fewer spurious timeouts than the RR scheduler for shorter minimum retransmission timeout settings, however, for longer settings the RR scheduler causes fewer spurious timeouts compared to the SIR scheduler. The minimum retransmission timeout has consequences for goodput fairness, but it does not affect the total system throughput. Both TCP versions produced similar results.
N/A / Link / Folke , Mats / 2005

Sulphide soil is the dominating fine-grained soil type along the east coast of the northern part of Sweden. A sulphide soil typically consists of clay and silt fractions with various and smaller content of sand. Sulphide soil may contain high amounts of iron mono sulphides (FeS) and organic content up to about 10%. A fine-grained sulphide soil normally shows low strength and high compressibility. Previous research concerning strength and deformation properties of Swedish fine-grained soils has very little included sulphide soil. It has been found that field and laboratory methods used to determine properties of other fine-grained soils, are often not suitable for sulphide soil. In this paper results from field and laboratory testing of fine-grained sulphide soil are presented and discussed. In the field, field vane tests, CPT-tests, dilatometer tests, seismic CPT-tests and undisturbed sampling are conducted. In the laboratory, triaxial tests, direct shear tests, oedometer tests, CRS-oedometer tests, routine tests of basic geotechnical properties and tests to determine chemical properties are done. In the laboratory, testing is carried out in room temperature as well as for in situ soil temperature for samples handled either at normal air conditions or at air free conditions. The main purpose of the research project is to find suitable testing methods in field and laboratory to determine mechanical properties of fine-grained sulphide soils. This includes how the results should be interpreted and evaluated and how samples should be sampled, transported, stored, handled and tested. In the paper the first part of the project is reported, including comparisons between properties and parameters determined in field and in laboratory. Effects on mechanical properties of testin g in room temperature versus in situ soil temperature and effects of handling the sample at air free conditions or not, are presented.
N/A / Link / Westerberg , Bo / 2005

Pervasive access to the Internet is driven by users who want wireless connectivity to ad hoc as well as infrastructure networks. Multi-hop wireless connectivity widens the coverage areas of access networks and enables two-way wireless traffic into previously dead-spot areas. This paper addresses network mobility issues, which are essential for roaming users who connect to the Internet through wireless access networks. We propose to support connectivity to wired infrastructure through multiple gateways with possibly different capabilities and utilization. Increased network performance can be achieved by adapting to variations in performance and coverage and by switching between gateways when beneficial. We present an efficient solution to enable ad hoc access to the Internet as well as interoperation of reactive routing protocols with Mobile IP. Our solution combines the benefits of proactive agent advertisement and reactive route discovery into a flexible multi-hop access network. We also discuss wireless network metrics that can be used for more intelligent decision making on gateway selection. The feasibility of our approach is validated by simulation and implementation.
N/A / Link / Brännström , Robert / 2006

Luleå tekniska universitet Övrigt
1-4020-5288-X / Link / Nordell , Bo / 2006

Luleå tekniska universitet Övrigt
Based upon a literature survey, a review is presented highlighting areas of research carried out into keyhole laser spot welding. The survey looks at parametric effects on weld geometry, types and formation of weld defects, the welding thermal cycle, pulse shaping, the use of image processing to investigate the process and modelling and simulation of processes such as the drilling and collapse of the keyhole and porosity formation.
0-912035-72-2 / Link / Kaplan , Alexander / 2002

Rheological measurements on materials with fibre-like inhomogeneities will be significantly affected by sample size when the in-plane dimensions of the sample are comparable with the length of the fibres. In this paper, a 310 t hydraulic press has been modified for squeeze flow rheology studies so that large tools that will minimize the influence of sample size can be used in combination with high closing velocities. Isothermal squeeze flow rheology experiments of GMT have been performed for closing velocities up to 30 mm/s corresponding to maximum closing forces of 1000 kN. Successful power law fits of closing velocity versus closing force have been performed for the velocity interval. Four different analytical models have been fitted to the experimental data and the accuracy in these has been investigated. The force prediction of the biaxial extension model is acceptable for the major part of mould closure, but better fits during the last part of mould closure were obtained using an additive model incorporating both shear and extensional flow.
N/A / Link / Vahlund , C F / 2002

Luleå tekniska universitet Övrigt
N/A / Link / Helgeson , Bo / 1979

Utilization of bottom ash in road construction may lead to a release of contaminants that can affect the soil of the swales constructed along these roads. Column tests were performed to evaluate the retention behavior of Cu, Cr, Zn, and Pb, originating from municipal solid waste incineration (MSWI) bottom ash leachate, in two substrates: peat and mould (a cultural soil). A chemical sequential extraction method was used to predict the risk associated with the release of the retained elements with modifications of environmental conditions. Apart from the dissolution of organic matter (OM), ash leachate properties hindered the metal transport from peat. Mould was efficient only in removing Zn, making it a less favorable substrate for the leachate control along the roads. Readily soluble forms made up a minor fraction of the retained metals in peat, reducing the risk of metal release due to ion exchange and pH drop. Changes in redox potential might be the main cause of Zn desorption from peat as the Fe-Mn oxides were the main scavengers for this metal. Oxidation of OM would be the primary reason of Cu and Cr release, while for Pb both fractions (Fe-Mn oxides and OM) might equally contribute to the metal discharge.
N/A / Link / Kumpiene , Jurate / 2006

Stabilization of soil contaminated with trace elements is a remediation practice that does not reduce the total content of contaminants, but lowers the amounts of mobile and bioavailable fractions. This study evaluated the efficiency of Fe(0) to reduce the mobility and bioavailability of Cr, Cu, As and Zn in a chromated copper arsenate (CCA)-contaminated soil using chemical, biochemical and biotoxicity tests. Contaminated soil was stabilized with 1% iron grit. This treatment decreased As and Cr concentrations in leachates (by 98% and 45%, respectively), in soil pore water (by 99% and 94%, respectively) and in plant shoots (by 84% and 95%, respectively). The stabilization technique also restored most of analyzed soil enzyme activities and reduced microbial toxicity, as evaluated by the BioTox test. After stabilization, exchangeable and bioaccessible fractions of Cu remained high, causing some residual toxicity in the treated soil.
N/A / Link / Kumpiene , Jurate / 2006

A method using CAD is presented for simplifying the problem of defining the heat input in finite element based welding simulations. The CAD system is used to define the weld path geometrically; this information is then used in the finite element analysis. Examples of the method's use are presented.
1-902653-56-4 / Link / Lundbäck , Andreas / 2002

Luleå tekniska universitet Övrigt
Genom införandet av den nya lagen om tre dimensionell fastighetsbildning i januari 2004 har möjligheterna för påbyggnad av befintliga byggnader ökat. Behovet av centralt belägna bostäder är idag stort i storstadsområdena. För att möta den efterfrågan och bibehålla en hållbar stadsutveckling kan lokaler med attraktiva lägen utnyttjas mer effektivt genom om-, till- eller påbyggnader. I detta forskningsprojekt har byggsystemet lättbyggnad med stål med särskild fokus på påbyggnader i kombination med industriellt byggande och 4D modellering studerats. Vidare har lättbyggnad med avseende på stålets utförbarhet för industriella produktionsmetoder utforskats. I två projekt, där lättbyggnadssystemet använts, har de använda industriella produktionsmetoderna studerats. Forskningsprojektet har också undersökt fem påbyggnadsprojekt. Problem uppkomna under produktionen relaterade till påbyggnadsprocessen har beaktas och de industriella byggmetoder som har använts i påbyggnadsprojekten har studerats. För att öka nyttan förinblandade parter har forskningsprojektet vidare haft syftet att utvärdera moderna projekteringshjälpmedel för informationshantering, såsom 3D CAD och 4D CAD. Inom ramen för projektet har 4D CADs möjligheter för att förenkla och förbättra denna process iakttagits. De industriella byggsystemen och produktionsmetoderna i de undersökta projekten var koncentrerade till fältfabrikproduktion snarare än helhetslösningar för hela leverantörskedjan och värdekedjan för byggprocessen. Många uppkomna problem under produktionstiden hade inte sin grund i själva byggsystemet och dess möjligheter för industriell produktion utan till hur man implementerade de förändrade krav som ett industriellt byggande medför. Lättbyggnad med stål har med sin lätta egenvikt samt smala toleranser stora möjligheter för industriella produktionsmetoder. Många av de upptäckta problemen i fallstudierna är relaterade till avsaknad av kunskap för planering och utförande av industriella produktionsmetoder samt bristande koordination mellan projektering och produktion på byggarbetsplatsen. Här har 4D CAD stora möjligheter att förenkla integreringen av projektering och produktion men också byggarbetsplaneringen. Med tanke på att vid påbyggnader är byggarbetsplatsen en av de viktigaste restriktionerna, måste byggarbetsplatsens aktiviteter beaktas. Logistikplaneringen på, till och från byggarbetsplatsen i alla de undersökta projekten kunde ha utförts mer koordinerat och därmed hade materialhanteringen till och från arbetsplatsen men även på byggarbetsplatsen effektiviserats mer.
N/A / Link / Bergsten , Susan / 2005

Luleå tekniska universitet Övrigt
90-5410-380-8 / Link / Tan , Xiangchun / 1994

There is a wide variety of industrial pastes or non-settling slurries pumped in mining, dredging and reclamation projects as products, refuse and tails. The types and/or names of some of the common ones are alumina red mud, phosphate clays, tar sands mature fine tails, tar sands (CT) consolidated clays and fly ash. The pipeline performance or friction of these varies dramatically with the type, its concentration and the particulars of the actual slurry making it difficult to select pumping equipment and to design associated pipelines. The GIW Hydraulic Laboratory in Grovetown Georgia has tested a number of these slurries over the last 30 years for various mining customers. Where available in the public domain and/or where permission has been obtained, the results of those tests are presented in this paper in a form usable for pipeline and pump system designers and users.
N/A / Link / Addie , Graeme / 2005

Co-landfilling of incineration ash and cellulose might facilitate the alkaline degradation of cellulose. A major degradation product is isosaccharinic acid (ISA), a complexing agent for metals. The impact of ISA on the mobility of Pb, Zn, Cr, Cu and Cd from a municipal solid waste incineration dry scrubber residue was studied at laboratory using a reduced 25-1 factorial design. Factors investigated were the amount of calcium isosaccharinate (Ca(ISA)2), L/S ratio, temperature, contact time and type of atmosphere (N2, air, O2). The effects of pH and Ca(ISA)2 as well as other factors on the leaching of metals were quantified and modelled using multiple linear regression (α = 0.05). Cd was excluded from the study since the concentrations were below the detection limit. The presence of Ca(ISA)2 resulted in a higher leaching of Cu indicating complex formation. Ca(ISA)2 alone had no effect on the leaching of Pb, Zn and Cr. A secondary effect on the mobilization was predicted to occur since Ca(ISA)2 had a positive effect on the pH and the leaching of Pb, Zn and Cr increased with increasing pH. The leaching of Pb varied from 24 up to 66 wt.% of the total Pb amount (1.74 ± 0.02 g(kg TS)-1) in the dry scrubber residue. The corresponding interval for Zn (7.29 ± 0.07 g(kg TS)-1) and Cu (0.50 ± 0.02 g(kg TS)-1) were 0.5-14 wt.% of Zn and 0.8-70 wt.% of Cu. Maximum leaching of Cr (0.23 ± 0.03 g(kg TS)-1) was 4.0 wt.%. At conditions similar to a compacted and covered landfill (4 °C, 7 days, 0 vol.% O2) the presence of ISA can increase the leaching of Cu from 2 to 46 wt.% if the amount of cellulose-based waste increases 20 times, from the ratio 1:100 to 1:5. As well, the leaching of Pb, Zn, and Cr can increase from 32 to 54 wt.% (Pb), 0.8-8.0 wt.% (Zn), and 0.5 to 4.0 wt.% (Cr) depending on the amount of cellulose and L/S ratio and pH value. Therefore, a risk (α = 0.05) exists that higher amounts of metals are leached from landfills where cellulose-containing waste and ash are co-disposed. This corresponds to an additional 29 t of Pb and 17 t of Cu leached annually from a compacted and covered landfill in the north of Sweden.
N/A / Link / Svensson , Malin / 2007

Polycrystalline tetra-nuclear Cu4[S2P(O-i-C3H7)2]4, hexa-nuclear Cu6[S2P(OC2H5)2]6, and octa-nuclear Cu8[S2P(O-i-C4H9)2]6(S) complexes were synthesized and analyzed by means of solid-state 31P CP/MAS and 65Cu static NMR spectroscopy. The symmetries of the electronic environments around each P-site were estimated from the 31P chemical shift anisotropy (CSA) parameters, Δaniso and η. The 65Cu chemical shift and quadrupolar splitting parameters obtained from the experimental 65Cu NMR spectra of the polycrystalline CuI-complexes are presented. A solid-state NMR approach for the elucidation of the stereochemistry of poly-nuclear Cu(I) dithiophosphate complexes, when the structural analysis of the systems by single-crystal X-ray diffraction is not readily available, is proposed.
N/A / Link / Rusanova , Daniela / 2006

The potential of nanofiltration for the separation of pharmaceutical and estrogenic compounds from salts in urine was investigated with the aim of producing a micropollutant-free nutrient solution that can be used as a fertilizer. A fresh urine solution and a synthetic solution of similar inorganic composition were tested at different pH values in order to investigate their separation behavior. These solutions were spiked with the micropollutants propranolol, ethinylestradiol, ibuprofen, diclofenac and carbamazepine. Among the membranes tested, NF270 showed the best performance with respect to the retention of micropollutants. The optimum retention of micropollutants was obtained at values of around pH 5. At this point, the retention of all micropollutants in non-hydrolysed urine was above 92%, while the corresponding value for the synthetic urine solution was above 73%. From the results, it can be concluded that the retention mechanism is determined by steric and electrostatic effects as well as by the partitioning of the micropollutants in the membrane. The nutrients urea and ammonia were well permeated, but phosphate and sulfate were almost completely retained. Nanofiltration can consequently be used to produce a permeate which contains most of the nitrogen and a greatly reduced proportion of micropollutants.
N/A / Link / Pronk , Wouter / 2006

N/A / Link / Emborg , Mats / 2005

Luleå tekniska universitet Övrigt
This article examines the factors that effect the efficiency of the CO sub 2 -laser powder cladding process. By theoretical calculation and experimental work it has been possible to identify how much of the original laser energy contributes to the cladding process and how much is lost to the surrounding environment by reflection, radiation, convection, etc. Every aspect of energy redistribution has been analyzed and quantified and this has led to a deeper understanding of the process. The article concludes with a number of suggestions for improving the efficiency of blown powder laser cladding.
N/A / Link / Gedda , Hans / 2002

81-89809-02-4 / Link / Woksepp , Stefan / 2006

1-905732-11-2 / Link / Toolanen , Bengt / 2006

In order to provide instantaneous three-dimensional radar measurements spanning the entire vertical extent of the ionosphere, the planned EISCAT 3D incoherent scatter radar system includes multiple receive-only antenna arrays, situated at 90-280 km from the main transmit/receive site. These will employ band-pass sampling at ∼80 MHz, with the input signal spectrum contained in the 6th Nyqvist zone. This paper presents simulations and methods used to investigate use of a post-ADC fractional-sample-delay (FSD) system necessary to perform true time-delay beamforming. To test the feasibility and limitations of the system an extensive simulation tool has been developed. The simulation system is implemented in matlab to provide cross-platform compatibility and can be applied to any similar system. Performance degrading aspects such as noise, jitter, bandwidth and resolution can be included in the simulations. The use of FIR-filters in the base-band of a band-pass sampled signal to apply true time-delay beam-forming is shown to be feasible.
0-7803-9744-4 / Link / Stenberg , Gustav / 2007