• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 35
  • 8
  • 8
  • 4
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 74
  • 33
  • 16
  • 10
  • 9
  • 9
  • 8
  • 7
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Extraction of logging residues for bioenergy : effects of operational methods on fuel quality and biomass losses in the forest / Uttag av skogsbränsle : hanteringens och lagringens inverkan på grotens bränslekvalitet samt biomassaförluster i skogen

Nilsson, Bengt January 2016 (has links)
Wood products play a key role in the transformation to a more sustainable society based on renewable bio-based resources, together with the positive effects on climate mitigation by replacing fossil fuels. However, to increase the use of forest fuel in practice it is important to understand the effects of handling and storage on its quality and removal of nutrients from the forest. This thesis addresses these effects with special focus on a comparative evaluation of the traditional dried-stacked with “new” and to some extent more controversial fresh-stacked methods for extraction of logging residues from Norway spruce (Picea abies (L.) Karst). The results indicate that a normal extraction of logging residues will leave at least 20% of logging residues at the clear-felled area, in accordance with Swedish Forest Agency recommendations. However, the results also indicate that the ambition of the dried-stacked method to leave the majority of the needles well spread over the clear-felled area does not meet these recommendations. In fact, the harvesting operation is more important than the extraction method, with respect to how much logging residues (nutrients) being left in the forest. The results also show that the quality of fuel yielded by the two handling methods differs only to minor extent, indicating that other factors have stronger effects, where “dried-stacked” and “fresh-stacked” logging residues from different clear-felling areas is often similar. Generally, logging residues stored over summer (regardless method), seem to provide sufficiently dry forest fuel, with a needle content of about 5–10%. There is a clear correlation between drying and effective loss of needles from twigs, but the loss does not necessarily mean that the needles will remain in the forest.  However, needle color (green or brown) is not a strong indicator for a reduction in needle content. Acceptance of the fresh-stacked method would provide opportunities for the development of new technologies, more efficient use of machinery throughout the whole year, reduced costs, shorter lead times and increased amounts of logging residues extracted from each clear-felled area. This is mainly because it would enable extraction at optimal times from a logistical, financial and/or forestry perspectives. Written in English with summary and conclusion in Swedish. / Skogen och dess produkter har en nyckelroll i omställningen till ett framtida hållbart samhälle eftersom användande av träråvara har en positiv effekt på klimatet, t.ex. genom träbyggande eller att fossila bränslen ersätts med bioenergi. Men för att kunna ta tillvara mer skogsbränsle i form av grenar och toppar (grot) från bestånd dominerade av gran (Picea abies (L.) Karst) är det viktigt att förstå hur hanteringen påverkar såväl bränslekvalitet som bortförsel av näringsämnen från skogen. Denna avhandling belyser hanteringens effekter på bränslekvalitet och näringsförluster genom att jämföra den traditionella metoden (skotning av torkad grot, ”brunrisskotning”), med den ”nya” och till viss del ifrågasatta skotningen av färsk grot (”grönrisskotning”). Resultatet visar att ett normalt grot-uttag kommer att lämna minst 20 % av groten kvar på hygget, helt i linje med Skogsstyrelsens rekommendationer. Däremot uppfylls inte rekommendationerna med avseende på att lämna merparten av barren väl spridda på hygget, detta trots att det är ambitionen med den traditionella hyggestorkningen av grot. Hur mycket grot (och således näringsämne) som lämnas kvar på hygget påverkas i själva verket mer av hur avverkningen utförs, än när groten skotas ihop. Resultatet visar också en skillnad i bränslekvalitet mellan de båda beskrivna hanteringsmetoderna. Denna skillnad är dock så liten att andra faktorer sannolikt påverkar mer än hanteringsmetoden. Hyggestorkad grot från ett enskilt hygge i södra Sverige, kan i verkligheten ofta vara ganska likt färskskotad grot från ett annat hygge. Grot som har lagrats över sommaren kan alltså förväntas ha torkat tillräckligt, samt ha en barrandel på ca 5–10 % oavsett hanteringsmetod. Det verkar också finnas ett klart samband mellan torkning och att barren släpper från kvisten, men det betyder inte nödvändigtvis att barren blir kvar i skogen. Hur som helst, barrens färg (gröna eller bruna) är inte en rättvisande indikator på avbarrning. Om skotning av färsk grot accepteras ger det möjligheter för utveckling av ny teknik, effektivare användning av maskinresurser över hela året, minskade kostnader, kortare ledtider, samt möjligt ökat grot-uttag från enskilda hyggen. Detta beror främst på att det skulle vara möjligt att utföra grot-uttaget när det passar bäst ur ett logistiskt, ekonomiskt och/eller skogligt perspektiv. Skriven på engelska, men med sammanfattning och slutsatser på svenska / <p><strong>Tidigare handledare har också varit:</strong></p><p>Thomas Thörnqvist, Professor, Linnéuniversitetet</p><p>Dick Dandberg, Professor, Linnéuniversitetet</p><p>Åsa Blom, Docent, Linnéuniversitetet</p><p><strong>Sammanläggningsavhandlingen består av totalt fyra Paper:</strong></p><p>Paper I</p><p>Nilsson, B., Blom, Å., Thörnqvist, T. 2013. The influence of two different handling methods on the moisture content and composition of logging residues. <em>Biomass and Bioenergy</em>, 52, 34–42.</p><p>Paper II</p><p>Nilsson, B., Nilsson, D., Thörnqvist, T. 2015. Distributions and losses of logging residues at clear-felled areas during extraction for bioenergy: Comparing dried- and fresh-stacked method. <em>Forests</em>, 6, 4212–4227.</p><p>Paper III</p><p>Nilsson, D., Nilsson, B., Thörnqvist, T., Bergh, J. 2016. Amount of nutrients extracted and left behind at the clear-felled area using the fresh- and dried-stacked method of logging residue extraction. Submitted to <em>Scandinavian Journal of Forest Research </em>(2016-11-01).</p><p>Paper IV</p><p>Nilsson, B., Lerman, P. 2016. Experimental study of relations between defoliation, moisture content and color change in logging residues. Department of Forestry and Wood Technology, Linnaeus University, Växjö, Sweden. <em>Manuscript</em>.</p>
62

Estudo da eficácia do agulhamento transconjuntival com 5-fluoracil em olhos com pressão intraocular elevada e bolha encapsulada pós trabeculectomia / The efficacy of transconjunctival needling revision with 5- fluorouracil in encapsulated blebs with elevated intraocular pressure after trabeculectomy

Suzuki, Ricardo 03 February 2014 (has links)
Objetivo: Estudo comparativo da pressão intraocular (PIO) após agulhamento transconjuntival (ATC) com 5-fluoracil (5-FU) e tratamento clínico (TC) em olhos glaucomatosos com bolha encapsulada e PIO não controlada após trabeculectomia com mitomicina C (MMC), no final de 12 meses de seguimento. Desenho: Estudo prospectivo, randomizado, intervencionista. Participantes: 40 olhos de 39 pacientes com bolha encapsulada, desenvolvida em 5 meses ou menos, após trabeculectomia primária com mitomicina e PIO >= 20mmHg. Métodos: Os olhos foram randomizados para ATC com 5-FU e TC. Um máximo de dois ATC foi permitido no estudo. Todos os olhos foram acompanhados por 12 meses. O sucesso foi definido como PIO <= 18 mmHg e redução de 20% da PIO basal (sem medicações no grupo ATC). Resultados: A média da PIO em 12 meses de acompanhamento foi de 12,14 ± 2,80 mmHg no grupo do ATC e 15,13 ± 2,07 mmHg no grupo do TC (p = 0,004). 14 olhos (70%) foram considerados sucesso no grupo do ATC e 15 olhos (75%) no grupo do TC (p = 0,89). O número médio de agulhamentos foi de 1,35 ± 0,49 e a quantidade média de medicamentos foi de 2,15 ± 0,74. Conclusões: Houve uma taxa de sucesso semelhante nos olhos randomizados para ATC com 5-FU em comparação com TC em 12 meses de seguimento. No entanto, foi observada uma significativa menor média da PIO, após o ATC / Objective: To compare de efficacy of transconjuctival needling revision (TNR) with 5-fluorouracil (5-FU) and medical treatment (MT) in glaucomatous eyes with encapsulated bleb and uncontrolled intraocular pressure (IOP) after trabeculectomy with mitomycin C (MMC) at 12 months follow-up. Design: Prospective, randomized, interventional study. Participants: Forty eyes of 39 patients with encapsulated bleb developed in 5 months or less following primary trabeculectomy with mitomycin and IOP >= 20mmHg. Methods: Eyes were randomized to either TNR with 5-FU or MT. A maximum of two TNR was allowed in the study. All eyes were followed-up for 12 months. Success of treatment was defined as IOP <= 18mmHg and a 20% reduction from baseline (no medications in TNR group). Results: Mean IOP at 12 months follow-up was 12.14 ± 2.80 mmHg in the TNR group and 15.13 ± 2.07 mmHg in the MT group (p=0.004). Fourteen eyes (70%) were considered a success in the TNR group and 15 eyes (75%) in the MT group (p=0.89). The number of needling procedure was 1.35 ± 0.49 procedures and the number of medication was 2.15 ± 0.74 medications. Conclusions: We have demonstrated a similar success rates in eyes randomized to MT in comparison to TNR with 5-FU at the last follow-up. However, a significant lower mean IOP after TNR was observed
63

Anestesisjuksköterskans erfarenheter av mötet med vuxna stickrädda patienter : en kvalitativ intervjustudie

Allhage, Susanne, Löfberg, Maria January 2010 (has links)
Studier visar att ungefär var tionde patient upplever stickrädsla, en rädsla för nålstick som gör att de undviker att söka vård vilket i sin tur kan leda till hälsoproblem på lång sikt. Att utföra venpunktion är en vanlig arbetsuppgift för anestesisjuksköterskan och hur hon hanterar patientens stickrädsla är av stor betydelse för hur patienten upplever vården som helhet. Anestesisjuksköterskan ska genom dialog med patienten bekräfta patientens rädsla och hjälpa patienten att känna trygghet på bästa sätt. När patienten upplever lidande på grund av vård, i detta sammanhang venpunktion uppstår vårdlidande och detta vårdlidande kan anestesisjuksköterskan förebygga. Syftet med studien är att beskriva anestesisjuksköterskors erfarenhet av mötet med vuxna patienter med stickrädsla. Åtta anestesisjuksköterskor intervjuades på fyra olika operationsavdelningar i Västsverige. Studien har en kvalitativ ansats och de utskrivna intervjuerna är analyserade med innehållsanalys. I resultatet framkom tre kategorier; stödjande faktorer och hindrande faktorer för anestesisjuksköterskan i mötet med den stickrädda patienten samt patientnära faktorer som påverkar mötet. Anestesisjuksköterskorna utför omvårdnadsåtgärder för att minska patientens vårdlidande och har som mål att göra det bästa för patienten. De ser och tolkar patienternas tecken på rädsla och bemöter dem utifrån dessa. Anestesisjuksköterskornas erfarenhet och kunskap gör att de blir trygga i sin yrkesroll och kan på så sätt skapa en trygghet hos patienten. / Program: Specialistsjuksköterskeutbildning med inriktning mot anestesisjukvård
64

Determining community attitudes and concerns with respect to the establishment of safer injection facilities in Vancouver's Downtown Eastside

Malowaniec, Leah January 2003 (has links)
Safer injection facilities (SIFs) provide a clean and supervised environment, thereby reducing health risks to drug users. Potential benefits include fewer overdoses, decreased rates of HIV, Hepatitis, and other blood-borne viruses, a reduction in open drug use, increased opportunities for health services and treatments, and cost savings to society. A pilot safer injection site is expected to open in Vancouver's Downtown Eastside in September 2003. This study assesses community attitudes and concerns with respect to SIFs. Focus groups with police officers, street nurses, and injection drug users in February and March 2003 revealed that they are supportive of the sites. Concerns related to the community impacts, external supports, administration, process, safety, and special populations (e.g. women, youth) were indicated. Special attention should be paid to the involvement of injection drug users in planning and programming, the inclusion of peer workers, the relationships between injection drug users, the wider population, and the police, and safety for marginalized populations. Recommendations to address concerns and ensure inclusive processes are provided.
65

Estudo da eficácia do agulhamento transconjuntival com 5-fluoracil em olhos com pressão intraocular elevada e bolha encapsulada pós trabeculectomia / The efficacy of transconjunctival needling revision with 5- fluorouracil in encapsulated blebs with elevated intraocular pressure after trabeculectomy

Ricardo Suzuki 03 February 2014 (has links)
Objetivo: Estudo comparativo da pressão intraocular (PIO) após agulhamento transconjuntival (ATC) com 5-fluoracil (5-FU) e tratamento clínico (TC) em olhos glaucomatosos com bolha encapsulada e PIO não controlada após trabeculectomia com mitomicina C (MMC), no final de 12 meses de seguimento. Desenho: Estudo prospectivo, randomizado, intervencionista. Participantes: 40 olhos de 39 pacientes com bolha encapsulada, desenvolvida em 5 meses ou menos, após trabeculectomia primária com mitomicina e PIO >= 20mmHg. Métodos: Os olhos foram randomizados para ATC com 5-FU e TC. Um máximo de dois ATC foi permitido no estudo. Todos os olhos foram acompanhados por 12 meses. O sucesso foi definido como PIO <= 18 mmHg e redução de 20% da PIO basal (sem medicações no grupo ATC). Resultados: A média da PIO em 12 meses de acompanhamento foi de 12,14 ± 2,80 mmHg no grupo do ATC e 15,13 ± 2,07 mmHg no grupo do TC (p = 0,004). 14 olhos (70%) foram considerados sucesso no grupo do ATC e 15 olhos (75%) no grupo do TC (p = 0,89). O número médio de agulhamentos foi de 1,35 ± 0,49 e a quantidade média de medicamentos foi de 2,15 ± 0,74. Conclusões: Houve uma taxa de sucesso semelhante nos olhos randomizados para ATC com 5-FU em comparação com TC em 12 meses de seguimento. No entanto, foi observada uma significativa menor média da PIO, após o ATC / Objective: To compare de efficacy of transconjuctival needling revision (TNR) with 5-fluorouracil (5-FU) and medical treatment (MT) in glaucomatous eyes with encapsulated bleb and uncontrolled intraocular pressure (IOP) after trabeculectomy with mitomycin C (MMC) at 12 months follow-up. Design: Prospective, randomized, interventional study. Participants: Forty eyes of 39 patients with encapsulated bleb developed in 5 months or less following primary trabeculectomy with mitomycin and IOP >= 20mmHg. Methods: Eyes were randomized to either TNR with 5-FU or MT. A maximum of two TNR was allowed in the study. All eyes were followed-up for 12 months. Success of treatment was defined as IOP <= 18mmHg and a 20% reduction from baseline (no medications in TNR group). Results: Mean IOP at 12 months follow-up was 12.14 ± 2.80 mmHg in the TNR group and 15.13 ± 2.07 mmHg in the MT group (p=0.004). Fourteen eyes (70%) were considered a success in the TNR group and 15 eyes (75%) in the MT group (p=0.89). The number of needling procedure was 1.35 ± 0.49 procedures and the number of medication was 2.15 ± 0.74 medications. Conclusions: We have demonstrated a similar success rates in eyes randomized to MT in comparison to TNR with 5-FU at the last follow-up. However, a significant lower mean IOP after TNR was observed
66

Persistentní organické polutanty v životním prostředí Jihomoravského kraje / Persistent Organic Pollutants in the Environment of the Southern Moravia Region

Lána, Radim January 2008 (has links)
Byla provedena studie bioakumulace POP v potravním řetězci a historických trendů hladin POP v sedimentech Brněnské přehrady. Současné úrovně kontaminantů byly stanoveny v jelci tloušti z řeky Svratky a rovněž byla posouzena hygienická kvalita ryb z rekreačního rybolovu. Současné úrovně POP v terestrickém ekosystému byly posouzeny pomocí analýz jehličí jako přirozeného indikátoru znečištění. Studium jedinců tří druhů dravých ptáků z ČR bylo zaměřeno na zhodnocení kontaminace těchto vrcholných predátorů POP. S pomocí analýz vybraných druhů ryb ze Záhlinických rybníků byl rovněž studován proces bioakumulace. Posouzení parametrů dvou moderních extrakčních technik a jejich využitelnosti pro izolaci POP z různých matric bylo námětem poslední části dizertace.
67

Aluminum levels in the O-horizon of soils near Sundsvall, Sweden : Are levels of Al elevated due to smelter emission? / Aluminium koncentrationer i jordars O horisont nära Sundsvall, Sverige : Är Al koncentrationerna förhöjda till följd av utsläpp från smältverket?

Sundin, Mattias January 2023 (has links)
Aluminum (Al) is a potentially toxic element for humans, animals, and plants. Al emitted from smelter plants is one source of Al that may be responsible for increased exposure to humans and the environment. In this study I investigated whether the Kubikenborg aluminum smelter (Kubal AB) emitted Al to such extent that it can be detected above regional background concentrations in soils and plants. The study was conducted by analyzing O- horizon cores and Scots’ pine (Pinus sylvestris) needles along two transects using X-ray fluorescence spectrometry (XRF). In the O-horizon cores, Al concentrations along the two transects (mean conc. 5250 mg kg-1 in T1 and 3472 mg kg-1 in T2) did not decrease with distance from the smelter. In Scots’ pine needles, Al concentrations (mean conc. 491 mg kg-1 in T1 and 590 mg kg-1 in T2) decreased significantly with distance along transect T2. Aluminum showed high negative co-variance with soil organic matter content (R2 = 0.47) and positive with silicon (Si) and titanium (Ti) in the soil (R = 0.84 and R = 0.86 respectively), suggesting that mineral dust is the main source of Al. However, the Al/Si ratio of the soil decreased with increasing distance from the smelter along T1, indicating a possible additional source of Al besides that of soil dust that may originate from smelter emission. Nevertheless, I found no strong support for detectable Al emissions in humus and Scots’ pine needles near the Kubal AB smelter.
68

Determining community attitudes and concerns with respect to the establishment of safer injection facilities in Vancouver's Downtown Eastside

Malowaniec, Leah January 2003 (has links)
No description available.
69

Bioenergy from Swedish forests : A Study of extraction methods, quality and effects for forest owners

Nilsson, Daniel January 2020 (has links)
The forest constitutes a very important element of renewable natural resources and makes a significant contribution to the Swedish bioeconomy. Biofuels are Sweden’s largest source of energy; of all the energy we use, 32% comes from biofuels, and of this approximately 85% comes from the forest and the forestry sector. In spite of this, logging residues constitute only a small component, compared to for example byproducts from sawmills and pulpindustry, and there is considered to be great potential for increasing their use. In 2019 the Swedish Forestry Agency issued new recommendations for logging residue harvest and ash recycling. This was a further development of the 2008 recommendations, which formed the foundation for how forest fuel producers work today, and were based on several decades of research into, for example, the impact on forest productivity and technological development of machinery. This practice of logging residue harvest aims to yield a dry and defoliated fuel where the needles are left at the clear felled area. However, if we are to increase the use of green renewable energy from forestry, it is very important to understand how different procurement systems affect the handling and storability of fuels from a quality perspective. It is also of great importance to understand, from the forest owners’ perspective, how removal of additional products from forestry influences nutritional balance and long-term productivity. If harvesting of logging residues does not affect long-term productivity, it is up to small-scale private forest owners to decide if removal of logging residues will be performed on their land. This thesis addresses some of these issues regarding removal of logging residues from the point of tree harvest up to the point of delivery to the energy conversion industry when the fuel chips are measured. Regarding different methods of handling of logging residues, the traditional method – dry-stacking – was compared with the, fresh-stacking method. The logging residues investigated came from stands that mainly consisted of Norway spruce (Picea abies (L.) Karst). The loads investigated in Paper 3 also came from logging of spruce-dominated forests. Both methods aim to dry the logging residues to an acceptable moisture content for delivery to the energyconversion industry. For the later part in the supply chain, moisture content measurements of logging residues were compared during a winter and summer season. The results of the studies indicate that the two methods do not create results that differ from what is allowed by the Swedish Forestry Agency and that they are quite similar with respect to dry mass- and nutrient removal from the clearfelled area. The results also show that similar yields and distributions of material are obtained from the logging residues with different stacking methods; in addition, the final felling itself, combined with the work performed by the forwarder operator, has a greater impact on the result than the method chosen for residue stacking of the logging residues. For the individual clear-felled area and the individual forest owner the increased removal associated with freshstacked logging residue has no major impact, however from a national perspective this small increase in removed logging residues may yield a supplement of between 0.5 – 1 TWh of green energy annually. Regardless of treatment, the studies indicated that the delivered fuel chips will have similar characteristics. The moisture content measurement techniques currently in use are sufficiently accurate and reliable. However, if the forest owner is unlucky and an error in measurement occurs or comminution and delivery happens during an especially wet period they may suffer a significant financial loss; indeed, it is generally not under the individual forest owners’ control when the logging residues are comminuted and delivered.
70

Anisotropic Mechanical Properties of the Guinea Pig Round Window Membrane

Wang, Wenbin January 2023 (has links)
Accessing the inner ear presents a significant challenge for the diagnosis and treatment of inner ear diseases. Many existing techniques to access the inner ear are invasive and can cause permanent damage to the cochlea. Recently, a novel microneedle has been fabricated to perforate the round window membrane (RWM) – a membrane sealing one of the two openings in the cochlea. These perforations enhance drug delivery into the inner ear, potentially improving the efficacy of therapeutics. Furthermore, they allow for the aspiration of perilymph samples, which is essential for diagnosing inner ear diseases. However, owing to limited knowledge about the mechanical properties of the RWM, certain technical aspects remain unexplored. Specifically, the interaction between the RWM and the microneedle during perforation is yet to be examined. This investigation is pivotal for the optimal design of microneedles — those robust enough to perforate RWMs yet delicate enough to minimize damage. In this thesis, we conduct a thorough examination of the guinea pig RWM, encompassing its geometry and its mechanical responses to pressures from the middle ear and inner ear. Additionally, we also formulate a comprehensive constitutive law for the guinea pig RWM. Our exploration begins with the creation of a U-Net model tailored to automatically segment the RWM. Despite the presence of other structures in the same image—such as bone, the basilar membrane, and ambient noise—the model proved invaluable for efficiently and automatically segmenting the RWM. To enhance accuracy, post-processing techniques like connected component analysis and majority voting were incorporated. Using this 3D model, we proceeded to study the RWM’s geometry. Recognizing the shrinkage observed in fixed RWMs, we integrated fresh RWM data to estimate the shrinkage ratio. Subsequently, we analyzed both the overall RWM thickness and that of the middle connective tissue layer—crucial metrics for future RWM modeling. Next, we proposed a method to evaluate the in-plane deformation of the RWM due to applied pressure. This involved using a bulge test system to pressurize and deform the RWM, combined with confocal microscopy to track stained nuclei or pre-introduced fluorescent beads on the RWM. We then utilized the coherent point drift (CPD) algorithm to measure the displacement of beads and nuclei. Results indicated that both markers could be successfully used to measure the RWM’s displacement. Further analysis revealed the in-plane Lagrangian strain of the RWM, with a significant observation being that the direction of maximum in-plane Lagrangian strain is perpendicular to the fiber direction. This underscores the crucial role of collagen fibers in determining the RWM’s mechanical properties. To conclude our study, we devised a constitutive law for the RWM, conceptualizing it as a combination of the ground substance and a family of dispersed fibers. This model was integrated into a FEBioStudio plugin, facilitating simulations of the RWM’s mechanical reactions to different pressures. Although our simulations closely aligned with experimental findings, some discrepancies were noted, likely stemming from an incomplete understanding of fiber dispersions. Nevertheless, our constitutive law reinforces the notion that fibers primarily govern the RWM’s mechanical characteristics.

Page generated in 0.0431 seconds