| 1. |
- Bhanbhro, Riaz, et al.
(author)
-
Basic description of tailings from Aitik focusing on mechanical behavior
- 2013
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In: International Journal of Emerging Technology and Advanced Engineering. - 2250-2459. ; 3:12, s. 65-69
-
Journal article (peer-reviewed)abstract
- Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct shear behavior are presented in this article. The results showed that particles size decreases along depth from surface for collected sample locations. The angularity of the particles increases as the grain size decreases. Vertical height reduction was observed during shearing of samples by direct shear tests.
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| 2. |
- Bhanbhro, Riaz, et al.
(author)
-
Mechanical Properties of Soft Tailings from a Swedish Tailings Impoundment : Results from Direct Shear Tests
- 2014
-
In: Electronic Journal of Geotechnical Engineering. - 1089-3032. ; 19:Z, s. 9023-9039
-
Journal article (peer-reviewed)abstract
- The shear strength of tailings can vary depending upon the type of ore and method of construction. Tailings dams may possess loose layers in subsequent layers, which may have low shear strength. Since the tailings dams are made-up to last for longer times, the strength parameters and material behaviors are essential to understand, especially potential for static liquefaction in loose layers. This article presents the results from direct shear tests performed on samples from loose layer of a tailings dam. Both drained and undrained tests are carried out. The results indicated the strain hardening behavior in tailings material which indicates loose condition. The shear strength was found to be relatively low as compared to typical values of tailings in literature. A contractant volume behavior was observed for all the tests. During shear tests the vertical height reductions in samples were observed. These changes were significantly increased after peak shear followed by slight increment in pore pressure along shearing angle. The reasons for these height changes are not fully known, but may be a rearrangement in skeleton or breakage of particles during shear which needs further investigative studies.
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| 3. |
- Bhanbhro, Riaz, et al.
(author)
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Mechanical Properties of Soft Tailings from different Depths of a Swedish Tailings Dam : Results from Triaxial tests
- 2020
-
In: Scientia Iranica. International Journal of Science and Technology. - Tehran : Sharif University of Technology, Scientia Iranica. - 1026-3098 .- 2345-3605. ; 27:3, s. 1066-1074
-
Journal article (peer-reviewed)abstract
- Construction of tailings dams is done in stages by raising it layer by layer depending on production rate of a mine. These layered dams may possess different strengths and materials properties in each layer i.e. strength parameters, behavior with loading. Tailings dams may have loose layers in subsequent layers, which upon further loading may be susceptible to stability issues. Identification of material properties and behavior is important to know for safety of dam with further raising and long term perspective modeling. This paper presents the results from drained Triaxial compression tests conducted on samples collected from loose layers, from different vertical depths of a tailings dam. The results indicated that depth did not show much influence on strength parameters determined by drained triaxial tests. The different confining pressures influenced the strain-stress behavior, high confining pressures stress-strain curve showed tendency to formulate straighten line of stress-strain curve, with contractant volume behavior along axial strains. The influence of void ratio on effective stress ratio was observed.
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| 4. |
- Arnesson, Marcus, et al.
(author)
-
Naturvärden i lövträdsmiljöer runt Värnanäs
- 2007
-
Reports (other academic/artistic)abstract
- Området vid Värnanäs har tidigare pekats ut för att ha internationella naturvärden. De inventeringar som presenteras här i rapporten bekräftar detta med många och mycket ovanliga arter. Den gemensamma nämnaren för de flesta av arterna är de gamla och grova träden framför allt av ek och bok. I samband med trädinventeringen noterades 2681 värdefulla träd, både levande träd, döda liggande, döda stående och högstubbar. Det största trädet är en ek med en omkrets på 969 cm. Eken tillhör med stor sannolikhet ett av landets tio största träd. Sammanlagt finns tio träd i området med en omkrets på över 6 meter, av dessa är nio ekar och en bokhögstubbe. Hela 66 inmätta träd har en omkrets på över 5 meter. Anmärkningsvärt är även den grova sälgen vid Halltorpsån med en omkrets på 450 cm samt tallen med en omkrets 482 cm, båda tillhör de absolut största av sitt trädslag i Sverige. I trädinventeringen noterades 1227 håliga lövträd av dessa var 446 ekar och 397 bokar. Där fanns också en hel del grova högstubbar och döda stående träd. Totalt noterades 56 bokar och 97 ekar som hade en brösthöjdsdiameter >40 cm. Sätts gränsen till >99 cm blir antalet 19 bokar och 30 ekar. Grova lågor är extremt sällsynt i dagens landskap men inom det inventerade området påträffades 59 bokar och 140 ekar med en basdiameter >40 cm. Sätts gränsen till >99 cm blir antalet 5 bokar och 30 ekar. Under 2006 inventerades vedlevande skalbaggar, fjärilar, lavar och svampar och 2004 inventerades fladdermöss. Antalet funna rödlistade arter bara under 2006 var: 65 skalbaggar, 6 fjärilar, 16 svampar och 14 lavar. Undersökningarna är inte heltäckande och flera tidigare funna arter som sannolikt finns kvar i området hittades inte under 2006. Området hyser också en rad rödlistade arter ur andra organismgrupper, noterat är bland annat 3 fladdermöss, 2 grod- och kräldjur samt 19 fåglar. En förutsättning för att behålla naturvärdena är att trygga förekomsten av gamla träd i området och spara alla former av död ved. Det finns ett stort behov att röja runt äldre träd. Det är också viktigt att skötseln görs på ett sådant sätt att antalet skyddsvärda träd ökar på sikt. En annan förutsättning är att de förekommer i en mosaik av öppna och halvöppna områden. Allt detta kräver skötsel i form av röjningar och bete. På de igenväxta markerna bör restaurering med efterföljande betesdrift ske snarast för att inte naturvärden ska gå förlorade. Ett annat problem, främst i bokbestånden, är att åldersblandningen homogeniserats via gallringar. För att naturvärdena på sikt ska bestå och utvecklas måste de gamla träden få tillräckligt med utrymme och nya gammelträd kontinuerligt bildas. Detta är mycket svårt att förena med produktionsinriktad skogsskötsel. Inventeringen av skyddsvärda träd ingår i det nationella åtgärdsprogrammet för skyddsvärda träd i kulturlandskapet. Området berörs av nio olika åtgärdsprogram och utöver det ovan nämnda är följande åtgärdsprogram aktuella för området: skalbaggar i eklågor (där svart guldbagge och brunoxe ingår), hotade bokskogsarter (där bokblombock och rombjätteknäppare ingår), läderbagge, havsörn, långbensgroda, sandödla, större vattensalamander och knubbsäl (Östersjöbestånd).
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| 5. |
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| 6. |
- Arup, Ulf, et al.
(author)
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Professor Ingvar Kärnfelt - a birthday tribute
- 2009
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In: The Lichenologist. - Cambridge : Cambridge University Press. - 0024-2829 .- 1096-1135. ; 41:5, s. 453-456
-
Journal article (other academic/artistic)abstract
- On 19 July 2009 Ingvar Kärnefelt celebrated his 65th birthday. This could have meant that we, his former students, would be celebrating him in his retirement from his position as head of the Biological Museums at Lund University. We are grateful that this is not the case, as Ingvar will carry on, probably for at least one or two more years. Instead, we celebrate Ingvar because he is the main reason for all of us having studied lichenology in Lund. This special issue of The Lichenologist is dedicated to him as a birthday tribute in honour of his long and fruitful lichenological career. The main authors of all the papers in this issue are former students of Ingvar. For several of us he has not only acted as supervisor but later also as the director of the Botanical Museum where we meet him in our daily work.
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| 7. |
- Berglund, Andreas, et al.
(author)
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Comparison between temperature based thaw weakening prediction model and field observation methods
- 2011
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In: Proceedings of the 21st International Conference on Port and Ocean Engineering under Arctic Conditions. - Montreal.
-
Conference paper (peer-reviewed)abstract
- Structures like roads and port yards located in cold climate are affected by freezing and thawing every year. The global trend of a warmer climate and temperatures around 0°C for longer periods of time will change the freezing/thawing behaviour in many locations. The tendency will changeto have several freezing /thawing cycles in a given location every year. The bearing capacity of low volume roads and simple port yards will be affected by a prolonged thawing period with lower bearing capacity as a consequence. Bearing capacity problems can lead to increased costs for traffic as well as increased maintenance costs. Due to very high costs for destroyed structuresduring thaw, a lot can be gained if bearing capacity problems at a given site can be forecasted well in advance in order not to destroy the structure. Such a method should preferably be based upon simple measurements like air temperatures to make it easy to use also in remote areas. In the described temperature based model air and ground temperatures are used to develop anaccumulated thaw index and corresponding limits. When the thaw index limit is reached, the construction at the evaluated depth thaws, leading to increased pore water pressure and reduction of strength and bearing capacity. This paper presents a study of the application of the model at low volume roads in Sweden. Bearing capacity at the road was evaluated from field tests by falling weight deflectometer (FWD) test carried out 24 times during the thawing season i.e.March 4 through June 9. Predictions made by the model were compared with the subgrade module evaluated from the FWD series. The results show that the model might be possible to use in Sweden and elsewhere if minor adjustments are carried out.
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| 8. |
- Bhanbhro, Riaz, 1985-, et al.
(author)
-
Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings
- 2017
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In: Canadian geotechnical journal (Print). - 0008-3674 .- 1208-6010.
-
Journal article (peer-reviewed)abstract
- Tailings material can have different material properties depending upon the type of ore and ore refining process and particle size distribution. Tailings dams are constructed as walk away solutions. Staged construction of tailings dams may lead to breakage of particles in subsequent layers resulting in change in particle sizes of material. This may lead to change in strength parameters upon change in particle sizes. This paper presents the direct shear tests performed on tailings material from a tailings dam. Remolded samples were manufactured in laboratory. The tailings material is separated in to four different particle sizes i.e.1-0.5mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The tests are performed on different normal stress levels as 50, 100, 150, 300 and 500kPa.The strength parameters are evaluated for each particle size and compared with said particle sizes. In order to study the effect of deposition, the tests are also performed on same material deposited in vertical and horizontal direction. This paper also describes the study of breakage of particles during direct shear tests by sieving the material at the end of each test.
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| 9. |
- Bhanbhro, Riaz, et al.
(author)
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Evaluation Of Primary And Secondary Deformations and Particle Breakage of Tailings
- 2015
-
In: From Fundamentals to Applications in Geotechnics. - : IOS Press. - 9781614996026 - 9781614996033 ; , s. 2481-2488
-
Conference paper (peer-reviewed)abstract
- Tailings are the waste product of mining which is left over after extraction of materials of interest. Tailings material may possess different material properties depending upon type of ore and method of concentration. Sometimes the tailings material itself is used in construction of tailings dams and tailings dams are constructed to withstand for long times. A tailing dam can be exposed to settlements due to incremental load as these dams are raised in stages. Increasing load with time may also lead to particle breakage. This article presents the results from oedometer tests conducted on tailings materials. The study includes the stress-deformation behavior and particle breakage of tailings material of different gradations upon application of incremental loads in oedometer tests. The samples were collected from different sections of tailings dam from Sweden. Remolded samples were manufactured in laboratory as four batches of particle sizes i.e. 1-0.5 mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The results are analyzed from tested samples at different stress levels and compared with different particle sizes. The breakage of particles of each batch is analyzed by sieving the specimens after oedometer tests. The results are evaluated in terms of primary and secondary deformations. The primary and secondary deformations are also compared with different particle sized specimens.
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| 10. |
- Bhanbhro, Riaz, et al.
(author)
-
Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests
- 2017
-
In: Electronic Journal of Geotechnical Engineering. - : Mete Öner. - 1089-3032. ; 22:06, s. 1717-1730
-
Journal article (peer-reviewed)abstract
- Tailings dams are raised with time depending upon rate of generation of waste. A tailings dam can contain different particle sized materials within its dam body. The newly raised embankment in a tailings dam can be considered as vertical load being applied on subsequent layer. The applied loads can cause deformations and breakage of particles. The particle breakage can then lead to a skeleton with new particle size particles and hence can lead to new material properties. This paper provides the results from triaxial tests conducted on uniformed particle sizes as, 0.5mm-0.25mm, 0.25mm-0.125mm and 0.125mm-0.063mm. The tests are performed at various effective radial stresses. The results are evaluated and compared with each particle size. The results include stress-strain and volumetric behavior during shearing, the effective stress ratio and stress-dilatancy plot. The friction angles are also evaluated and compared with different particle sized specimens. It was found that effective stress ratios were slightly higher when tests were performed at lower confining stresses and vice versa. It was also observed that particle size did not show any effect of friction angles.
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| 11. |
- Bhanbhro, Riaz, et al.
(author)
-
Mechanical Properties and Particle Breakage of Uniform-Sized Tailings Material
- 2021
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In: Journal of materials in civil engineering. - Luleå : American Society of Civil Engineers (ASCE). - 0899-1561 .- 1943-5533. ; 33:3
-
Journal article (peer-reviewed)abstract
- Tailings dam disasters are reported almost every year and are triggered by mechanisms, such as overtopping, piping, and others.The failures due to inadequate management cannot be neglected as well. These dams are constructed mostly in a step-by-step constructionmethod that leads to a continuously changing state of vertical loads during construction and may lead to particle breakage and changes instrength. Therefore, a layer of tailings dam today may not be the same tomorrow during the construction phase. To study the effects ofdifferent loads on particle breakage and strength, direct shear tests were performed on remolded tailings samples that were separated intodifferent particle sizes. The tests were performed using different normal stresses that ranged from 50 to 500 kPa. The results indicate that finertailings exhibited slightly more shear resistance than that of coarser tailings irrespective of the deposition method. For normally depositedspecimen, the dilatant and contractant behavior in vertical height was observed when the normal effective stress was less than 300 kPa andgreater than 300 kPa, respectively. Under the vertical deposition method, the finer tailings showed contractant height behavior when subjectedto a normal effective stress of 300 kPa. The friction angle and the cohesion of vertically deposited specimens were slightly higher and slightlylower, respectively, than that of normally deposited ones. The breakage of tailings particles was observed to be proportional to the particle sizeof the tailings.
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| 12. |
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| 13. |
- Dahlberg, Anders, et al.
(author)
-
786 svampar på 2015 års rödlista
- 2015
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In: Svensk Mykologisk Tidskrift. - 1653-0357. ; 36, s. 91-97-
-
Journal article (pop. science, debate, etc.)abstract
- A new Swedish Red List was published April 28th 2015 by the Swedish Species Information Centre in which 786 species of fungi are listed. Compared to the previous Red List published in 2010, 11 species have been down-listed, 51 species have been added and 35 species have changed names or taxonomic rank, thus the list has increased by 41. The changes are mainly due to increased knowledge of taxonomy, ecology and distribution, not to changes in the sta-tus of the species. Here, the members of the Species Specialist Group for Fungi 2011 – 2015 summarize the results of the red listing.
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| 14. |
- Dahlberg, Anders, et al.
(author)
-
Den nya rödlistan har 746 svampar
- 2010
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In: Svensk mykologisk tidskrift. - 1653-0357. ; 31:2, s. 37-47
-
Journal article (peer-reviewed)abstract
- The new Red List that was recently presented by the Swedish Species Information Centre (Gärdenfors 2010) includes 746 species of fungi considered to be threatened. Compared to the previous Red List published in 2005, 36 species have been down-listed whereas 150 species have been added, thus the list has increased by 114. The changes are above all due to increased knowledge of taxonomy, ecology and distribution. In the present paper members of the Species Specialist Group for Fungi 2006-2010 summarize the background and results of the red-listing process and present the habitats in which the red-listed species occur.
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| 15. |
- Dahlberg, Anders, et al.
(author)
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Svampar – Fungi
- 2010
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In: Rödlistade arter i Sverige 2010 – The 2010 Red List of Swedish Species. - 9789188506351 ; , s. 231-246
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Book chapter (other academic/artistic)
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| 16. |
- Dahlberg, Anders, et al.
(author)
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Svampar Fungi
- 2020
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In: Rödlistade arter i Sverige 2020. - 9789187853548 ; , s. 67-88
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Book chapter (other academic/artistic)
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| 17. |
- Dahlberg, Anders, et al.
(author)
-
Svampar Fungi
- 2015
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In: Rödlistade arter i Sverige 2015. - 9789187853104 ; , s. 53-71
-
Book chapter (other academic/artistic)
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| 18. |
- Edeskär, Tommy, et al.
(author)
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Grundläggning av vindkraftverk med hänsyn till tjäle
- 2010
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In: Bygg och Teknik. - 0281-658X .- 2002-8350. ; 102:1, s. 68-73
-
Journal article (pop. science, debate, etc.)abstract
- På grund av den snabba utbyggnaden av vindkraftverk är erfarenheten från byggande i kallt klimat för dessa konstruktioner begränsad. Den forskning som bedrivs idag är mestadels inriktad mot vindkraftens miljöpåverkan samt frågor för att underlätta utbyggnaden och förbättra kostnadseffektiviteten, Statens energimyndighet (2008). Utbyggnad av vindkraftverk i extrema miljöer skapar nya frågor som bör utredas för att säkerställa verkens kvalitet i ett långtidsperspektiv. I denna artikel vill vi belysa frågan om tjäle och hur den är kopplad till grundläggning av vindkraftverk.
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| 19. |
- Edeskär, Tommy, et al.
(author)
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Numerical analysis of frost penetration around footings of power mills in subarctic conditions
- 2009
-
In: Proceedings of the 20th International Conference on Port and Ocean Engineering under Arctic Conditions.
-
Conference paper (peer-reviewed)abstract
- The potential for establishing wind power farms in the subarctic areas is high due to the combination of large available areas and few conflicting interests. In subarctic climate frost and thaw are major principal design aspects. In foundation work the major impact of frost action is at the outer peripheries of the foundation. Therefore most analysis work and prevention actions such as insulation around the foundation are concentrated to this part of the structure. The gravity foundations of wind power plants are often constructed as a reinforced concrete monolite. In the centre of the footing a steel cage is attached for anchoring the wind mill tower. This steel cage ends close to the sub-grade and can due to considerably higher thermal conductivity, compared to the concrete structure, transport a lot more heat. By FEM analysis, the frost penetration around, and under two typical wind-power foundations have been analyzed for different climate conditions in Sweden. In addition, different soil types have also been used. The result shows that the frost penetration in the centre of the foundation needs to be considered. Further it is shown that it is larger in the centre than compared to the periphery.
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| 20. |
- Edeskär, Tommy, et al.
(author)
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Use of scrap tyres as insulation layer in road construction
- 2007
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In: Proceedings of the 8th International Symposium on Cold region Development ISCORD 2007. - : RIL - Finnish Association of Civil Engineers.
-
Conference paper (peer-reviewed)abstract
- Used tyres are not allowed to be placed on landfills any more, but can be used as insulation materials with very good results. The present paper describes a study in which tyre shreds (50mm * 50 mm) were used as insulation material in a road construction. The tyre shreds had a thickness of 600 mm and were covered with 875 mm of road superstructure. The effect of the layer on frost depth and frost heave was measured during three winters. As scrap tyres are a highly elastic the bearing capacity and Young's module were measure directly on the road by the use of a falling weight deflectometer. The potential environmental impact was also studied. The scrap tyres showed a very good insulation performance, mostly due to its high porosity. Effects of frost action were not visible or recorded. The studied construction had deformation pattern of the road surface was within acceptable limits. The environmental impact was studied before the pavement was placed at the top and therefore leakage could be detected.
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| 21. |
- Jeppson, Mikael, et al.
(author)
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Hotspots för sällsynta svampar i Ölands sandstäpper och annan sandvegetation.
- 2008
-
Reports (other academic/artistic)abstract
- Buksvampar (Gatseromyceter) såsom jordstjärnor, stjälkröksvampar, diskröksvampar är svampar väl anpassade till torra och på andra sätt ekologiskt krävande naturtyper. Genom sin speciella morfologi och ekologi utgör de ett mycket viktigt inslag i mer eller mindre stäppliknande miljöer. Påfallande många har sina växtplatser i kalkrika områden med sandmarker utsatta för speciella klimatförhållanden såsom långvarig torka, oregelbunden nederbörd och höga sommartemperaturer. De olika vegetationstyperna på sandmarker beskrivs i rapporten liksom dess karakteristik och mångfald av svampar och kärlväxter. Viss utblick görs även internationellt. Skillnaderna mellan vegetationen i olika sandrika områden är stor bl.a. tack vare olika hög grad av påverkan av kalkrik sand resp. urlakning. Dessa pH-förhållanden har även stor inverkan på den funga som kan påträffas i olika områden. Erfarenheter från svamparna bidrar i hög grad till ett utvidgat synsätt på ”stäpp-” resp. ”hedserien” i sandmarksvegetationen. Bland annat så förekommer ett antal ”stäppsvampar” ofta i vegetationstyper även utan samband med en av dess ledarter tofsäxing (Koeleria glauca). Dessa insikter bör bidra till ett vidare synsätt på termen ”sandstäpp” till att omfatta vegetationstyper på kalkrik sandmark, även om tofsäxing saknas. De i rapporten behandlade svamparterna presenteras vad gäller öländsk, nationell och internationell status samt något om deras hot och ekologi. Många av dem presenteras i bild. Sammanlagt har 33 olika arter röksvampar (i vid bemärkelse) påträffats i de öländska sandmarkerna varav 19 bedömdes som naturvårdsintressanta i den bemärkelse att de visar på skyddsvärda och/eller hotade biotoper. Av de funna arterna är 16 rödlistade (3 CR, 7 EN, 2 VU och 4 NT). För många av arterna utgör de öländska förekomsterna betydande andelar av de svenska och i vissa fall även europeiska populationerna. Fältbesök gjordes på ett 50-tal lokaler för de utvalda svamparna 2006-2008 och i rapporten presenteras de 39 mest värdefulla lokalerna på Öland för rödlistade och naturvårdsintressanta buksvampar (Gasteromyceter) växande i sandrika habitat på Öland. Lokalerna avgränsas, deras naturvärden och dagens markanvändning beskrivs översiktligt. Vidare ges ett tidsfönster med bedömningar av graden av hot mot lokalen och i de flesta fall specificeras åtgärdsbehov och rekommendationer ges för framtida skötsel. Av de 39 värdefullaste lokalerna ansågs 24 (62 %) tillhöra den högsta naturvärdesklassen medan nio (23 %) resp. sex (15 %) bedömdes ha något lägre prioritet för naturvården. Åtgärdsbehovet ansågs akut på sju av lokalerna (18 %) men nästa lika angelägna (”snarast”) på 13 lokaler (33 %). Nitton av lokalerna (49%) har ett utseende och markanvändning som idag upprätthåller bra förutsättningar för sandsvamparna. Rapporten är framtagen för att underlätta urval och prioriteringar av naturvårdsåtgärder de närmast kommande åren. De öländska sandmarkslokaler som ur mykologisk synpunkt hyser högsta naturvärde och samtidigt är i akut behov av skötselåtgärder om inte naturvärdena ska försvinna är: • Gåtebo sandstäpp, Bredsättra • Gårdby sandhed, Gårdby • Triberga-Alby mosse, Hulterstad • Sandby kyrkvägskäl, Sandby
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| 22. |
- Knutsson, E, et al.
(author)
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What determines complementarity of product bundles and how is attraction influenced?
- 2006
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In: 13th conference on recent advances in retailing and consumer services, Budapest, Hungary.
-
Conference paper (peer-reviewed)abstract
- Product bundling is a commonly used marketing strategy. The simplest form of bundling is selling multiples of the same product in a package, but there are also multi-product bundles that include different products. Multi-product bundles aim at fulfilling more than one need. In multi-product bundles the relation between individual items can vary. Complementary bundles consist of products that are functionally compatible, while non-complementary bundles are functionally unrelated. The purpose of the present study is to investigate whether it is the complementarity in terms of functionality or a general categorization of the products that result in different attraction and whether the degree of complementarity is dependent on type of anchor product and the price discrepancy between the products in the bundle. The results indicate that if the price is not lower, bundles are never more attractive than the separate products. In addition to functionality, price differences as well as differences in quality play a role for how attractive bundles are.
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| 23. |
- Knutsson, Tommy, et al.
(author)
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Djävulssopp, falsk djävulssopp och deras djävulskt lika dubbelgångare : röda relikter i släktena Rubroboletus och Imperator funna i Skandinavien
- 2016
-
In: Svensk mykologisk tidskrift. - 0280-5057. ; 37, s. 12-25
-
Journal article (pop. science, debate, etc.)abstract
- By molecular methods and DNA-analyses five new genera, previously included in Boletus sect. Luridi Fr. sensu Singer, have recently been introduced, viz. Suillellus, Exsudoporus, Neoboletus, Rubroboletus and Imperator. In this paper the genera Rubroboletus and Imperator are presented in more detail. In Scandinavia three Rubroboletus species and one Imperator species have so far been reported: R. satanas, R. legaliae, R. rhodoxanthus and I. rhodopurpureus. All of them are red-listed and extremely rare in Scandinavia, which is the northern limit of their European distributions. They are considered relict species from earlier, warmer periods. All species prefer open, sun-exposed localities in broad-leaved woodlands or tree-covered pastures and meadows. Historically these species have caused much taxonomic confusion. This paper presents the current knowledge of the species characteristics, ecology and distributions in Scandinavia.
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| 24. |
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| 25. |
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| 26. |
- Rodriguez, Juan, et al.
(author)
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Effect of vertical load on tailings particles
- 2016
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In: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 6:2, s. 115-129
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Journal article (peer-reviewed)abstract
- Tailing dams could store hundreds, thousands or millions of cubic meters of tailings result of the mining extractive industry. Mechanical behavior of this man-made soil should be known in order to maintain a safe storage. Dykes rise up to form the dams and they are buildup with the same tailing material especially in the upstream method using the coarse part. The study uses oedometer classical test to determine the load effect over tailing coarse particles. Tailings are site specific and so its characteristics. It is necessary to understand the tailings degradations to achieve safe impounds. The study comprises four samples of one range-size tailing particles (e.g. 1-0.5, 0.5-0.25, 0.25-0.125, 0.125-0.063mm) subject to vertical load in traditional oedometers. Vertical load effects are measured using two dimensional image analysis and sieving. Results show that 0.063mm sample is the only one that has change in shape with low breakage (<1%) while the rest of the sizes have no shape change but high breakage is present especially in fraction 0.5mm. Settlements also are more pronounced in coarse fractions 0.5 and 0.25mm.
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| 27. |
- Rodriguez, Juan M., et al.
(author)
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Particle Shape Quantities and Measurement Techniques–A Review
- 2013
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In: Electronic Journal of Geotechnical Engineering. - : Mete Öner. - 1089-3032. ; 18/A, s. 169-198
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Journal article (peer-reviewed)abstract
- It has been shown in the early 20th century that particle shape has an influence on geotechnical properties. Even if this is known, there has been only minor progress in explaining the processes behind its performance and has only partly implemented in practical geotechnical analysis. This literature review covers different methods and techniques used to determine the geometrical shape of the particles. Particle shape could be classifying in three categories; sphericity - the overall particle shape and similitude with a sphere, roundness - the description of the particle’s corners and roughness - the surface texture of the particle. Thecategories are scale dependent and the major scale is to sphericity while the minor belongs to roughness. The overview has shown that there is no agreement on the usage of the descriptors and is not clear which descriptor is the best. One problem has been in a large scale classify shape properties. Image analysis seems according to the review to be a promising tool, it has advantages as low time consumption or repeatability. But the resolution in the processed image needs to be considered since it influences descriptors such as e.g. the perimeter. Shape definitions and its potential role in soil mechanics are discussed.
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| 28. |
- Rodriguez, Juan, et al.
(author)
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Mechanical weathering effect on tailing particles
- 2016
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In: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM.
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Conference paper (peer-reviewed)abstract
- Over the last century the tailing volume generation has grown dramatically due to the mineral demand. Nowadays the mining industry is producing every year millions of tons of tailings. The storage of the tailings has become a challenge due to the increased storage capacity demanded. Physical risk associated to the tailings dams is the stability itself since tailing dams are considered a walk-away solution. Physical changes as breakage and shape occur to the tailing particles affecting the stability of the fills by reduced strength properties. In order to understand the reduction and shape changes of tailing particles degradation test by milling attrition (erosion) and image analysis was conducted. Uniform fractions 1-0.5, 0.5-025, 0.25-0.125 and 0.125-0.063mm were used.Results have shown that attrition agents e.g. ball attrition can increase the physical erosion but also change the shape of the particles compared with autogenous attrition. However particles shape has become more regular (less elongated) and rounded in coarse fractions 1-0.5 and 0.5-0.25mm while smaller fractions 0.25-0.125 and 0.125-0.063mm seems to have opposite behavior. Comparison with previous milling studies show consistent differences probably due to the breakage of the particles was the objective. In perspective if tailings become more rounded the strength could be compromised. More studies are needed to verify this.
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| 29. |
- Rodriguez, Juan, et al.
(author)
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Shear Strength in Uniformed Sized Tailing Particles
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In: International Journal of Geotechnical Engineering. - 1938-6362 .- 1939-7879.
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Journal article (peer-reviewed)abstract
- Mining industry provides mineral to the modern society. Minerals are indispensable raw materials for commodities. A by-product of the mineral extraction is the mine waste also called tailings. Tailings are safety storage in tailing dams. Tailings dams troughs the history had had incidents and failures. Economic, environmental and social consequences of a tailing dam failure could be devastating. Soil strength is given by the consolidation, particle shape, stresses path, water content, hydraulic conductivity among other factors. Change on these factors produces changes in the soil strength. The development of economical and fast tests could improve the safety of the tailings deposits. Drained direct shear tests using uniformed graded tailing particles were performed. Three different size ranges 0.25, 0.125 and 0.063mm were used. Effect of particle size on shear strength and the effect of shearing on the tailing particles were studied. Normal consolidation pressure, void ratio, particle size and particle shape were monitored properties. Strength of the tailings was related with the monitored properties to suggest four empirical relations, two of them base in the morphology of the particle and two bases in the angularity. Results have shown that particle elongation diminishes the tailings strength but the angularity increases the strength. Particle size results are ambiguous and seem to be more related with the shape descriptor.
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| 30. |
- Sundberg, Sebastian, et al.
(author)
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Nytt i nya rödlistan
- 2015
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In: Svensk Botanisk Tidskrift. - 0039-646X. ; 109, s. 188-207
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Journal article (other academic/artistic)abstract
- The new Swedish Red List of vascular plants, bryophytes, algae, lichens and macrofungi is briefly presented. These groups now comprise more than 1800 red-listed species, corresponding to 21% of the assessed species. A net increase of 170 red-listed species since 2010 is mainly the result of more data to base the assessments on. For the first time, four sections in the plant genus Hieracium have been assessed, resulting in an addition of 327 apomictic plant species to the Red List. Logging of old-growth forest and overgrowth of former open and semi-open habitats (mainly because of ceased management of semi-natural habitats) are the stressors that harm most species, while eutrophication, drainage, water level regulation and exploitation are also important. The dieback of the elm species Ulmus glabra, U. minor, and ash Fraxinus excelsior, because of invasive pathogens, negatively affects many species of lichens, fungi and bryophytes being dependent on these host trees. In the forest landscape, the main challenge is to allow forestry without clear-cutting large areas and to maintain mixed stands regarding tree species and age distribution. In the agricultural landscape the challenge is to maintain and improve management by grazing and mowing in semi-natural grasslands, but also wooded areas, despite a continuous decline in the number of domestic cattle. In valuable wetlands and lakes, the negative impact of old ditches and water level regulation should be reduced. Species conservation in urban areas, like cities (lawns, parks and gardens), road verges and former sandpits, poses a promising challenge where much more could be done to improve the situation for red-listed species.
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| 31. |
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| 32. |
- Svedberg, Bo, et al.
(author)
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FUD - SALA : provsträcka med stabilisering av obundna lager
- 2008
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Reports (other academic/artistic)abstract
- The objective of the project is to develop two applications, in which a subbase is stabilized using binders, for full scale demonstration. The binders that were used are cement, Merit 5000 and fly ash. The work indicates that stabilization of unbound layers are expected to improve the bearing capacity of the road construction though the total depth of the structure is reduced. The developed applications are durable against freezing and thawing cycles, will not be lifting due to frost and are not considerably insulating. In a life cycle cost perspective the applications are likely to be favourable. Next step is to perform a full scale demonstration where amongst other knowledge regarding determination of modulus, frost durability and cost aspects related to maintenance should be developed further.
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| 33. |
- Svensson, Måns, et al.
(author)
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Taxonomic novelties and new records of Fennoscandian crustose lichens
- 2017
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In: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; :25, s. 51-86
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Journal article (peer-reviewed)abstract
- We present taxonomic, distributional and ecological notes on Fennoscandian crustose lichens and lichenicolous fungi, based on new collections as well as revision of herbarium material. Two new combinations are proposed: Frutidella furfuracea comb. nov. for F. pullata and Puttea duplex comb. nov. for Fellhanera duplex. Lecidea byssoboliza, L. carneoglauca and Variolaria torta are all reduced to synonymy with Bacidia antricola, Bacidia invertens is synonymized with B. igniarii, B. atrolivida with Mycobilimbia tetramera, and Gyalidea fruticola with Thelenella pertusariella. A new description is provided for Micarea hylocomii. 25 species of lichens and lichenicolous fungi are reported as new to Finland, Norway and/or Sweden: Absconditella lignicola (Norway), Bacidia antricola (Norway), B. polychroa (Norway), B. pycnidata (Sweden), Bacidina adastra (Sweden), Biatora veteranorum (Norway), Briancoppinsia cytospora (Finland), Catillaria scotinodes (Norway), Cliostomum subtenerum (Norway), Dirina fallax (Sweden), Fellhaneropsis almquistiorum (Norway), Gyalidea subscutellaris (Sweden), Lecania inundata (Norway), L. suavis (Norway), Micarea capitata (Norway), M. deminuta (Norway), M. hylocomii (Sweden), M. lynceola (Sweden), M. soralifera (Sweden), M. subconfusa (Sweden), Mycoblastus sanguinarioides (Finland, Sweden), Paralecia pratorum (Sweden), Puttea duplex (Sweden), Sarcogyne algoviae (Finland) and Toninia subnitida (Norway). Lectotypes are designated for Bacidia antricola, Lecidea byssoboliza, Lecidea carneoglauca, Lecidea subconfusa and Lecidea submoestula.
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| 34. |
- Söderström, Patrik, et al.
(author)
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Snow grooming using machine guidance for piste management processes : Case study: Ormberget ski piste
- 2013
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Reports (other academic/artistic)abstract
- The snow is an increasingly precious commodity to the ski industry's production of pistes. To preserve this commodity is the basis for economic production. The wear on the groomed snow consists primarily of two reasons: skiers and melting. A slope that is optimally processed will last longer and require less maintenance. In addition to this obvious that maintenance must be planned based on where wear has taken place there is an additional planning variable, namely time. Timing is of utmost importance when it comes to snow as a material. A process model will be presented covering a systematic approaches how road construction technologies can be adapted to the snow grooming process. The expected results are a process model which can be used in order to optimize the snow grooming management in order to extend the skiing season. There is possibly two ways of doing this. Firstly to optimize the snow mass haul management process during the skiing season. Secondly re-build the different piste off season to create better environmental conditions during season. This study consists of four kinds of data. Laser scanned data for 3D terrain modeling of ski piste (ground) and collected data by snow groomer for 3D terrain modeling of ski piste during the objective period of investigation. The differences between 3D terrain models by laser scanning and snow groomer is representative of snow depth for corresponding day. Furthermore, in order to verify the method, snow depth and snow surface are measured by group of students from Luleå University of Technology.
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| 35. |
- Tibell, Leif, et al.
(author)
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Calicium episcalaris (Caliciaceae), a new lichen species from Sweden
- 2016
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In: Symbolae Botanicae Upsalienses. - 0082-0644. ; 38, s. 49-52
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Journal article (peer-reviewed)abstract
- A new species of lichens, Calicium episcalaris Tibell & Knutsson, is described from Sweden. It is one of few Calicium species being parasitic or ‘Jugendparasit’, occurring on Hypocenomyce scalaris (Ach.) M.Choisy growing on an old wooden building in South Sweden.
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| 36. |
- Zamora, Juan Carlos, et al.
(author)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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In: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Journal article (peer-reviewed)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 37. |
- Zeinali, Amin
(author)
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Thaw Mechanism in Subgrades
- 2018
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Licentiate thesis (other academic/artistic)abstract
- Freezing-thawing, changes the properties of soil due to the phase change of the water in the soil body. Freezing-thawing cycles in the soil have been studied for several decades including extensive laboratory research. In this study, the main focus is thawing based on laboratory investigation. The soil used in the laboratory study is taken from a minor road where an additional field study has been carried out.A freezing-thawing laboratory apparatus is manufactured and used in order to get better understanding of the freezing-thawing process. The apparatus is designed for cylindrical sample, one dimensional heat flow, freezing/thawing from top to bottom, water supply from bottom (access to external water) and possible to apply overburden load.he laboratory tests were conducted at similar soil samples at different boundary conditions. Water is liberated in the thawing zone of the sample. During thawing the only drainage path is to the surface, however, water migrates upwards even when entire soil is thawed. Upwards water migration after thawing period can be due to the changes in thawed soil properties such as permeability and fine particles redistribution. The rate of thawing is a very important factor for thawing conditions. At low thawing rate the drainage capacity of sample is sufficient to drain the liberated water from ice. Moreover, freezing condition i.e. access to water, has high impact on thawing process. If the volume of ice lenses is high,the thawed soil fluidizes as the water migrates upwards. Pore pressure transducers will be added to the apparatus for further investigation regarding both freezing and thawing.The field study has been conducted in order to study thaw behavior in low volume road embankment. The scope of the study is to investigate the thaw weakening progress by Falling Weight Deflectometer (FWD) and Dynamic Cone Penetration (DCP) tests on low volume embankment road near Luleå,northern Sweden. The results from methods is compared and the differences in how they are capturing the thawing is discussed. DCP which is known as an easy and cheap method to estimate stiffness of soil layers is applied to estimate thawing period and the layer which thaw weakening takes place at. Stiffness gained by back calculation of FWD results which is performed on the same road embankment and same period of time DCP test is done.
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