Baigiamajame darbe tiriama grynų ir mišrių maumedynų našumas ir paplitimas Lietuvoje (pagal Lietuvos miškų kadastro elektroninę duomenų bazę, 2010). Darbo objektas – Lietuvos miškuose augantys maumedžiai bei gryni ir mišrūs maumedynai (pagal Lietuvos miškų kadastro elektroninę duomenų bazę, 2010). Darbo tikslas – ištirti svetimkraštės medžių rūšies maumedžio bendrijų našumą, paplitimą, taksacinius ypatumus ir juos palyginti su kitų Lietuvos spygliuočių medžių rūšių (paprastosios pušies ir paprastosios eglės) medynų parametrais. Darbo metodai – monografinis, dokumentų ir taksacinių normatyvų analizės bei taikomosios statistikos metodai. Darbo rezultatai. Atlikus maumedynų tyrimus nustatyta, kad gryni ir mišrūs maumedynai Lietuvoje užima 748,8 ha plotą. Turime 727 miško sklypų su grynais ir mišriais maumedynais. Bendras miškų, kuriuose auga maumedžiai, plotas lygus 2337,7 ha. Miškininkai neįvardina maumedynų rūšies tikslumu (kaip ir Lietuvos beržynų, kuriuos sudaryti gali karpotojo beržo arba plaukuotojo beržo medžiai). Lietuvoje dominuoja Europinio maumedžio medynai. Visi Lietuvos maumedynai kultūrinės kilmės. Jau 50 metų amžiuje (Ld augavietėje) maumedynai pasiekia 380 m3/ha, o brandžiuose ir perbrendusiuose maumedynuose tūris siekia net 800 – 1300 m3/ha. Maumedžiai Lietuvos miškuose pasiekia rekordinį 40 – 45 m aukštį, o savo gimtajame areale - net 55 m aukštį. Lietuvos teritorijoje dominuoja jauni maumedžio miškai (Lietuvos maumedynų vidutinis amžius 36 metai). Bendras... [toliau žr. visą tekstą] / In master's thesis were investigated Lithuanian Larch stands and their productivity. Object of the research work – Larch forests in Lithuania. The aim of the work – is to determine Larch prevalence in Lithuanian state and private forests. Analyze the estimation of forest parameters and compare with local coniferous tree species (Scots Pine and Norway Spruce) stands that grow in similar conditions. Methods of the research work - documents analysis, electronics database analysis The results of the work. Analysis showed that in Lithuania Larch stands occupies 748,8 ha. Best performance was in Ld forest site at age of 50 Larch stand reaches average 380 m3/ha stand volume. Old Larch Stands reach 1300 m3/ha.

No description available.

In an effort to increase machining efficiency and minimize costs, research into tool condition monitoring (TCM) systems has focused on developing methods to allow for unmanned machining. For drilling processes, such systems typically use indirect approaches to monitoring the tool condition by measuring spindle torque and feed force as well as vibrations including acoustic emission (AE – mechanical vibrations faster than 100 kHz). This project aimed to advance the state-of-the-art in the area of TCM by developing a method to detect sudden tool failures in large diameter (> 25 mm) indexable insert drills. This project was a continuation of the research conducted by Mr. R. Griffin (a former MSc student), who developed a model capable of predicting long term wear trends in indexable insert drills [1]. Notably, his model was unable to react to sudden tool breakage due to tool chipping, which was addressed by this project as presented in this thesis. In order to develop and train models able to detect sudden tool failure, an experiment was developed and installed in the field of the industry partner of this project. The experiment’s main feature was a pair of AE sensors added to the existing torque and force sensors. On this setup, experiments were conducted by drilling 2251 holes in workpieces using indexable insert drills with or without the insert breaking. When drilling holes without the insert breaking, the holes were named as good ones; and when drilling holes with the insert breaking they were named as bad holes. During the drilling process, data was collected from current sensors attached to the spindle motor and feed motor as well as from an AE sensor on the spindle and on the workpiece. From the signals from the spindle motor current and feed motor current sensors, algorithms were developed to identify and divide the signals of drilling a hole into different sections of the drilling cycle (i.e. entrance, steady-state, exit, etc.). Steady-state time-domain features were extracted from the sensor signals measured for all holes drilled in the experiments and the extracted features were used to train and test the classifier models. These models were cross validated to determine which type of model was the best fit for the drilling data collected. The results from the classifier models show that most of the classifiers tested have the ability to identify sudden tool breakage based on the data recorded in the present study, with varying degrees of success. The naïve Bayes classifier was able to detect the most failures but suffered from a large number of falsely detected failures. Both the classification tree and linear discriminant analysis classifiers had lower failure detection rates than the naïve Bayes classifier, but did not suffer from the same amount of false positives; as such, these two classifiers had higher overall classification rates than the naïve Bayes. These results suggest that classification tree and linear discriminant analysis methods are better suited for the drilling application and that the time-domain features should be complemented by others, such as the features extracted from the frequency domain, to accurately diagnose the tool condition. Future research should focus on extracting frequency and time-frequency domain features as these features might contain more information on tool condition. In addition, methods of examining features at the entrance and exit of the holes should be investigated as these two points in the drilling cycle are the most prone to sudden tool failure.

Whiplash injury is a common and troublesome disorder and approximately 10-40 per cent of its victims develop chronic symptoms. The annual incidence is estimated at 1/1000 inhabitants and the prevalence at 1%. The cause of chronic symptoms after whiplash injury is still unknown and no effective treatment has been presented so far. The present study is divided into two parts; the first part includes clinical, radiographic and psychological investigations, and the second part the effect of surgical intervention as well as intervention with medication. MRI studies (n=39) showed a larger proportion of pathologic findings compared to normal subjects, but no correlation with initial neurologic deficits was found. At the 2-year follow-up all patients with disc herniations with medullary impingement had persistent symptoms. Three patients had disc herniations that deteriorated from slight and moderate initial changes on the MRI to severe changes with medullary cord impingement. This deterioration might be a first sign of disc degeneration. Thus our results indicate that disc pathology is a contributing factor in the development of chronic symptoms. Measurements from standard lateral radiographs taken in neutral position were evaluated (n=48). A graphic digitizer connected to a microcomputer was used and the sagittal diameters were determined. Multivariate analysis of variance showed that the spinal canal was significantly smaller in patients with persistent symptoms indicating that a narrow spinal canal is unfavourable in patients subjected to whiplash injury. A psychological investigation (n=70) revealed no relationship between pre-existing personality traits and persistent symptoms. In our study, whiplash patients showed no differences in personality traits compared to normal controls. Our results after discectomy and anterior cervical fusion (n=20) because of chronic symptoms after whiplash injury were not satisfactory. We noticed that about half of the cases had less headache and neck pain but no beneficial effects on radicular pain, vertigo, visual and auditory symptoms were observed. Based on the criteria of a surgical evaluation, two patients were classified as good, nine as fair and nine as poor. A prospective randomised double-blind study of high-dose methyl-prednisolone compared to placebo was conducted (n=40). A clinical follow-up with repeated neurological examinations and a standardised questionnaire including VAS-scales and a pain sketch form were used for the evaluation of initial symptoms, before drug administration and at the follow-ups at 2 weeks, 6 weeks, and 6 months after the injury. At the 6-month follow-up there was a significant difference between the actively treated patients and placebo concerning disabling symptoms defined as inability to return to previous work, number of sick-days and sick-leave profile. All the actively treated patients had returned to work and none had multiple symptoms though three of them complained of intermittent neck pain. Our conclusion is therefore that acute treatment with high-dose corticosteroids might be beneficial to the prevention of disabling symptoms after whiplash injury. / <p>Härtill 6 uppsatser</p> / digitalisering@umu

The primary prerequisites for powder mixtures/granules intended for tableting is to posses the quality of (i) homogenous composition; (ii) acceptable flowability, (iii) sufficient compressibility; and (iv) anti-adhesiveness. The most important prerequisite for these powder mixture/granulates is undoubtedly the ability to flow, due to its effect on product quality, especially dose and dosage form uniformity. A comprehensive literature study on the flowability of powders revealed that flow is affected by physical properties such as molecular- and interparticle forces, particle size and size distribution, particle shape, particle density, surface structure of the particle, and particle packing geometry. Various flow tests are available to determine powder flow, each measuring a variety of the properties mentioned above, resulting in different flow results and a subsequent variation in the classification of powders. Particle characterization of a wide range of pharmaceutical fillers through SEM and particle size analysis, indicated considerable differences between physical properties of the various fillers, which suggested significant differences in their flow behaviour. Flow tests were conducted determining the critical orifice diameter (COD); percentage compressibility (%C); angle of repose (AoR) and flow rate (FR) of the fillers in the absence and presence of a glidant (0.25% Aerosil® 200). The results confirmed the expected differences in flow obtained from the various tests, with no one of the fillers achieving the same flow behaviour in all the tests. The difference in flow amongst the fillers for a specific test could, to a large extent, been correlated with specific physical properties of the particles within the powder bed. COD results illustrated the influence of particle size and shape and surface structure on the flowability of these materials, with fillers with a smaller average particle size, less spherical shaped particles and uneven / rough surface structures performing poorer than their counterparts. The percentage compressibility (%C) of the materials was affected by the shape and size of the particles and the density of the materials, whilst the packing geometry also affected flow behaviour. Particles with high density and a low internal porosity tended to posses free flowing properties. Powders with a larger difference in the ratio between their respective bulk and tapped densities/volumes presented better flow results. The AoR of the fillers was affected by the cohesiveness and friction between the particles as well as the shape, surface structure and size of the particles. This method was less discriminative in terms of indicating differences in the flow of powders with comparable physical properties. A further drawback of this method was the variation in results between repetitions, which is affected by the way the samples were handled prior to measurement. The flow rate (FR) of the fillers was predominantly affected by the density of the materials and the size, shape, and surface structure of the particles. Powders with a higher density seemed to exhibit a better flow rate, although some of the other factors affected the flow rate more when the densities were very close or identical. The following general rank order for the various fillers (as an average of their performance in all the tests) were established (with no glidant present): Cellactose® 80 > FlowLac® 100 > Prosolv® HD90 * Ludipress® > Emcompress® >Avicel® PH200 > Starlac® » Emcocel® 50M * chitosan » lactose monohydrate. Addition of a glidant failed to change the rank order significantly. During the final stage of the study an attempt was made to modify and/or refine the composite flow index (CFI) proposed by Taylor ef a/. (2000:6) through (i) inclusion of flow rate results in its computation and/or (ii) varying the contribution (percentage) of each test to the CFI (Taylor & co-workers used equal contributions, namely 33 V* %, in their calculation of the CFI). The results indicated that including the results from the flow rate test was not beneficial in terms of providing a more representative CFI (in fact it reduced the accuracy of the index). Next various weight ratios for COD, %C and AoR was used to determine the CFI of each filler, and an optimum ratio was found at 50%:40%:10% (COD:%C:AoR) resulting in the highest CFI for each powder and the widest range for the CFI (largest difference between minimum and maximum values). This ratio was found in the presence and absence of a glidant. At this ratio the CFI discriminated well between the different powders in terms of their flowability. Lastly, the flowability scale for powders as used by the USP (20007:644) for %C and AoR results was adapted and fitted on the CFI results obtained for the various powders. This scale provided an exceptional fit for the powders both in the absence and presence of a glidant) and offered an excellent means for the grouping and classifcation of powders based on their CFI. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

The primary prerequisites for powder mixtures/granules intended for tableting is to posses the quality of (i) homogenous composition; (ii) acceptable flowability, (iii) sufficient compressibility; and (iv) anti-adhesiveness. The most important prerequisite for these powder mixture/granulates is undoubtedly the ability to flow, due to its effect on product quality, especially dose and dosage form uniformity. A comprehensive literature study on the flowability of powders revealed that flow is affected by physical properties such as molecular- and interparticle forces, particle size and size distribution, particle shape, particle density, surface structure of the particle, and particle packing geometry. Various flow tests are available to determine powder flow, each measuring a variety of the properties mentioned above, resulting in different flow results and a subsequent variation in the classification of powders. Particle characterization of a wide range of pharmaceutical fillers through SEM and particle size analysis, indicated considerable differences between physical properties of the various fillers, which suggested significant differences in their flow behaviour. Flow tests were conducted determining the critical orifice diameter (COD); percentage compressibility (%C); angle of repose (AoR) and flow rate (FR) of the fillers in the absence and presence of a glidant (0.25% Aerosil® 200). The results confirmed the expected differences in flow obtained from the various tests, with no one of the fillers achieving the same flow behaviour in all the tests. The difference in flow amongst the fillers for a specific test could, to a large extent, been correlated with specific physical properties of the particles within the powder bed. COD results illustrated the influence of particle size and shape and surface structure on the flowability of these materials, with fillers with a smaller average particle size, less spherical shaped particles and uneven / rough surface structures performing poorer than their counterparts. The percentage compressibility (%C) of the materials was affected by the shape and size of the particles and the density of the materials, whilst the packing geometry also affected flow behaviour. Particles with high density and a low internal porosity tended to posses free flowing properties. Powders with a larger difference in the ratio between their respective bulk and tapped densities/volumes presented better flow results. The AoR of the fillers was affected by the cohesiveness and friction between the particles as well as the shape, surface structure and size of the particles. This method was less discriminative in terms of indicating differences in the flow of powders with comparable physical properties. A further drawback of this method was the variation in results between repetitions, which is affected by the way the samples were handled prior to measurement. The flow rate (FR) of the fillers was predominantly affected by the density of the materials and the size, shape, and surface structure of the particles. Powders with a higher density seemed to exhibit a better flow rate, although some of the other factors affected the flow rate more when the densities were very close or identical. The following general rank order for the various fillers (as an average of their performance in all the tests) were established (with no glidant present): Cellactose® 80 > FlowLac® 100 > Prosolv® HD90 * Ludipress® > Emcompress® >Avicel® PH200 > Starlac® » Emcocel® 50M * chitosan » lactose monohydrate. Addition of a glidant failed to change the rank order significantly. During the final stage of the study an attempt was made to modify and/or refine the composite flow index (CFI) proposed by Taylor ef a/. (2000:6) through (i) inclusion of flow rate results in its computation and/or (ii) varying the contribution (percentage) of each test to the CFI (Taylor & co-workers used equal contributions, namely 33 V* %, in their calculation of the CFI). The results indicated that including the results from the flow rate test was not beneficial in terms of providing a more representative CFI (in fact it reduced the accuracy of the index). Next various weight ratios for COD, %C and AoR was used to determine the CFI of each filler, and an optimum ratio was found at 50%:40%:10% (COD:%C:AoR) resulting in the highest CFI for each powder and the widest range for the CFI (largest difference between minimum and maximum values). This ratio was found in the presence and absence of a glidant. At this ratio the CFI discriminated well between the different powders in terms of their flowability. Lastly, the flowability scale for powders as used by the USP (20007:644) for %C and AoR results was adapted and fitted on the CFI results obtained for the various powders. This scale provided an exceptional fit for the powders both in the absence and presence of a glidant) and offered an excellent means for the grouping and classifcation of powders based on their CFI. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

In the first phase of this project three enhanced large diameter (> 60 cm) residential wells were constructed at a study site in Lindsay, Ontario. Two wells were constructed using concrete tile casing while the other well was constructed using galvanized steel casing. Javor (2010) evaluated various aspects of drinking water well construction and design to determine the susceptibility of residential large diameter drinking water wells to surface water and airborne contamination. One of the purposes of these new installations was to remove the uncertainty with respect to construction methods, age and maintenance that is characteristic of residential drinking water well performance studies. Javor (2010) conducted a field and laboratory study to assess the performance of several design changes that were thought to improve the integrity of large diameter drinking water wells. These experiments were also used to determine whether one design was more prone to atmospheric and/or surface water contamination than another. During the second phase of this project routine monitoring was continued and data pertinent to assess the performance of the test wells were collected using the same instrumentation. This routine monitoring involved the visual inspection of the wells, collection of well water elevation, collection of soil temperature profile data, collection and analysis of water samples, and collection of cumulative water volumes extracted from the test wells. In addition to the routine monitoring, a ground penetrating radar (GPR) survey was performed in October 2010 to complement the previous data collected during February 2010. Smoke tracer tests were performed under non-frozen and frozen conditions to re-assess the potential pathways of contaminants between the atmosphere and the interior of the test wells. Bacteriological indicators and high concentrations of two dissolved ions were detected in all test and monitoring wells. The smoke tracer tests demonstrated that pathways for airborne contaminants to enter the test wells exist with similar pathways observed in the winter and the summer. GPR surveys indicated that the bentonite slurry annular sealant was the most homogeneous media. A baseline characterization of the microbial nature of the biofilm performed in three of the test wells (CTH1, ETH1 and ETH3) indicated that the sessile bacteria are more metabolically diverse than suspended bacteria, and that this diversity is even higher in the concrete cased wells. Biofilm characterization performed on concrete, fibreglass and galvanized steel coupons incubated in two of the test wells (concrete and galvanized steel) showed that bacteria in the concrete cased wells barely colonized on fiberglass and galvanized steel, while bacteria in the galvanized steel cased well did not have difficulty colonizing on any of the casing materials. The results of the biofilm cleaning study indicated that the use of pressure washing combined with chlorination effectively removed biofilm grown on galvanized steel and fibreglass casing materials. This study investigated various factors that could affect the performance of large diameter drinking water wells. Since the test wells used in this study were under the direct influence of surface water a comparison between the various annular sealants was problematic. However, the three enhanced test wells outperformed the conventional test well. The observations from the smoke tracer tests performed under non-frozen and frozen conditions indicate that the Poly-Lok lid seam is the most prevalent pathway for airborne contaminants to enter a well. Fibreglass may be the preferred choice for large diameter well casing material since fibreglass is corrosion resistant, lightweight, easy to install, has a high strength to weight ratio, and a greater degree of biofilm was able to be removed from fibreglass casing material than from galvanized steel casing material.

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Due to the fact that cross flow fuel injection is widely used in gas turbine engines combustors, it is important to understand the mechanisms that control the spray breakup within the cross flow. In spite of a lot of work done in this field, very few studies have been carried out under conditions typical of aerospace applications. This thesis describes a series of experiments carried out to simulate these conditions in order to characterize the formation of spray within a high speed, high pressure and high temperature cross flow close to conditions typical of aerospace applications. Fuel spray characteristics were studied for Jet-A fuel injected into a crossflow (M=0.2 and M=0.35) of preheated (T=555K) air at a chamber pressure of 4 atm. It was seen that larger droplets could be found in the periphery of the spray while smaller droplets could be found closer to the injection plate. In most cases, the droplet velocities were seen to lag the incoming air flow velocity by 20-40% and a spray hat structure was created by the jet in crossflow near the injection wall most likely caused by vortex flow created around the liquid column (jet). The influence of Weber number was then studied. It was seen that shear breakup mechanism dominates at We greater than about 100. Droplets diameters were found to be in the range of 15-30 microns for higher values of We, while larger droplets (100-200 microns) were observed at Weber number of 33. The initial sharp-edged injector was then replaced by a smooth-edged injector having. Spray characteristics from the two injectors were compared. The spray produced by the smooth countersunk injector penetrated further into the test section away from the injector orifice by approximately 2mm. This injector also produced droplets with a significantly smaller mean diameter (D10). The average droplet velocities in the vertical direction deviated from the incoming air flow velocity to a lesser degree using the countersunk injector. Meanwhile, droplets from this injector had a higher average velocity in the direction of fuel injection between the core of the spray and the orifice wall.