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RELEASE OF MICRO- AND NANOSCALE PLASTICS FROM SYNTHETIC TEXTILES DURING LAUNDRY AND QUANTIFICATION OF NANOSCALE PLASTICS BY SINGLE PARTICLE INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRYMahbub, Md Shahriar 01 May 2022 (has links)
Plastic wastes released in the environment can produce microplastics (MPs, Size < 5 mm) and nanoscale plastics (NPs, Size < 100 nm) due to the environmental weathering processes. The presence of the MPs and NPs have been found worldwide in different aquatic and terrestrial environments. These tiny plastics have detrimental health impacts when they are ingested or inhaled by aquatic organisms as well as human beings. However, their occurrences including identification and quantification in the environment are still a great challenge. Particularly, quantification for NPs is a challenge, as there is no standard technique available yet that can count the NPs effectively. Therefore, this thesis was focused on two important aspects related to microplastics (MPs) and nanoscale plastics (NPs). Firstly, assess the source of MPs or NPs release and secondly, NPs quantification. Microfibers (MFs) are one of the most abundant portions of MPs in the aquatic environment, which are shed during the washing and drying of fabrics. Hence, in the first area of the study, the release pattern of MPs, in the form of acrylic MFs from portable washer and dryer during fabric washing and drying under different conditions were investigated. Additionally, the subsequent degradations behavior of these released MFs under ultraviolet light (UV-A) irradiation were explored. The results indicated that the MFs were released almost 2 times higher when the fabrics were washed for 60 min compared to 30 min due to higher mechanical stresses. In addition, MFs released were increased by 1.4 times higher when the fabrics were dried for 60 min compared to 30 min due to longer rotational forces on the fabrics. The use of detergent during washing promoted 2.7 times more MF release compared to without detergent. Moreover, MFs were released approximately 1.8 times higher from washing when washed with 40°C of water than with 20°C of water. However, subsequent washing cycles showed decreasing patterns of MF releases during washing and drying, approximately 45% less and 67% less, respectively in the 7th wash compared to the 1st wash as the fabrics approach a plateau. The released acrylic MFs were analyzed after their exposure to UV-A irradiation in the aquatic environment from 0 day to 182 days. After 182 days of UV-A irradiation, released acrylic MFs showed significant changes in the surface morphology in the form of cracks, holes, and flakes determined by scanning electron microscope (SEM). The formations of cracks, cavities, and flakes in the MF’s surface were proportional to the period of UV-A exposure. Dimensions of the formed holes and cracks on the UV-A degraded MFs suggested that MFs can turn into NPs in presence of water and UV-A exposure in the environment. Hence, a robust analytical tool must be optimized to detect these tiny degraded NPs in the aquatic environment. This brings to the second area of the study which aimed to optimize and validate a method to detect NPs through coating with synthesized gold nanoparticles (AuNPs) by Single Particle Inductively Coupled Plasma Mass Spectrometry (SP-ICP-MS). This study successfully detected the polystyrene nanoscale plastics (PS NPs, size 61 nm) by particle-by-particle analysis in single quadrupole-based SP-ICP-MS and the detection limit of particle number concentration was reached up to 8.64 × 10^7 particles/L. PS NPs were selected as a model nanoscale plastic as it is one of the most abundant plastics in the environment. The method was applied to PS NPs in deionized (DI) water which achieved a good amount of PS NP recoveries by up to 98%. This analytical technique can be further optimized and might be helpful for analyzing NPs in any environmental samples to determine their occurrences and concentrations.
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Bärförmågetillväxt i pålad friktionsjordDahlberg, Stina January 2012 (has links)
Piled friction soil show a set-up which is increasing with the time after installation. The cost could be reduced if the set-up had been taken into account when designing but in Sweden it is very unusual to do that. Previous studies showed that set-up can vary between 25 % and 75 % during the first 90 days after pile installation. This showed that the effect of the phenomenon is difficult to predict. A study involving five projects have been carried out by specifying certain parameters like pile type, method for pile installation and test method for measure the bearing capacity in friction soils located in Sweden. The expectations from this study were whishes that the large dispersion should be reduced. This was not the case. One example of the wide dispersion is two piles which are 29 meters long and installed in Södertälje. One of the piles had a set-up of 249 % for 21 days while the other one had a loss of 7 % in bearing capacity during the same time interval. Since these large dispersions encountered it was found that soil characteristics and composition has a major impact on the coming set-up. Friction soil exhibit variations in properties such as how dense it is, the variety and size of layers in the soil profile and grain size. These are all not possible to determine if it not is a research project or some kind of project where detailed surveys are can be done considering time and money. Another parameter that indicated to have impact on the outcome of the phenomenon was the order of installations of the piles. Stress rearrangement in the soil is one of the mechanisms behind the set-up. An empirical relationship to predict the bearing capacity has been used as the piles have been compared with each other. An interesting finding of the study showed that the pile length influences how large the pile set-up gets. One design method for piles that takes into account the pile set-up is the ICP-method but is barely used in Sweden. To see how well and if this method match the results from dynamic pile tests calculations has been done. Average showed that the ICP-method gave a 13 % lower bearing capacity than the real value. There are several reasons that this method differs from the values from test data. For example the CPT tests were not as deep as the piles so the stress from the pile toe is just extrapolated. The friction angle in the soil is based on empirical data which means that the friction angle between concrete and soil is empirical as well which affect the result significantly.
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Development of an ICP-based Global Localization System / Utveckling av ett ICP-baserat Globalt LokaliseringssystemNylén, Rebecka, Rajala, Katherine January 2021 (has links)
The most common way to track the position of a vehicle is by using the Global Navigation Satellite System (GNSS). Unfortunately, there are many scenarios where GNSS is inaccessible or provides low precision, and it can therefore be vulnerable to only rely on GNSS. This master's thesis is done in collaboration with the Swedish Defence Research Agency (FOI), who is looking for a solution to this problem. Therefore, this master's thesis develops a system that globally localizes a vehicle in a map, without GNSS. The approach is to combine odometry and the scan registration algorithm iterative closest point (ICP), in an extended Kalman filter (EKF), to provide global position estimates. The ICP algorithm aligns two different sets of data points, referred to as point clouds. In this thesis, one set consists of light detection and ranging (LIDAR) data points collected from a sensor mounted on a vehicle, and the other consists of LIDAR data points collected from an aircraft which forms an elevation map of the area. In the ideal case, the algorithm finds the position on the elevation map where the vehicle collected the data points. For the EKF to function, the uncertainty of ICP must be estimated. Different methods are investigated, which are; unscented transform based covariance, covariance with Hessian, and covariance with correspondences. The result shows that all the methods are too optimistic when estimating the uncertainty. The reason is that none of the methods take all sources of error into account, and it is therefore difficult to correctly capture the uncertainty of ICP. The unscented transform based covariance is the least optimistic, and covariance with correspondences is the most. A second problem investigated in this thesis is how odometry and ICP with an elevation map as reference can be combined to provide a global position estimate. As mentioned, the chosen approach is to implement an EKF which weights the different data sources based on their covariance, to one single estimate. The developed global localization system is evaluated in a real time experiment, where the data is recorded using equipment from FOI. The goal of the experiment is to localize a vehicle while it is driving in different environments, including urban, field and forest environments. The result shows that the performance of the system is viable, and it manages to provide localization within a few meters from ground truth. However, since the ICP covariance estimates are not fully accurate, the performance of the EKF is decreased as it cannot weight the different estimates properly. The ICP algorithm used in the system has a lot of flaws. The worst is that it easily converges to incorrect solutions, in other words that it estimates the wrong position of the vehicle. How this risk can be decreased is also investigated in this thesis. A method that decreases this risk drastically, and makes the viable performance of the system possible, is developed. The approach of the method is to exclude incorrect positions by removing a large amount of points from the point clouds, and keeping the most informative. By only utilizing the most informative data points in the point cloud, global positions with high accuracy are achieved.
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Development and Application of a Method for Determination of Metals in Environmental SedimentsNguyen, Tuong Van 04 May 2023 (has links)
No description available.
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Design and Fabrication of Out-of-Plane Silicon Microneedles with Integrated Hydrophobic MicrochannelsDiehl, Michael S. 15 August 2007 (has links) (PDF)
Microfabricated needles have the potential for inexpensive drug delivery without pain. The ability to deliver medication painlessly to patients will someday be not just hoped for but expected by the general public. The commercialization of this technology will also lead to other valuable technologies, such as systems that continually monitor and control insulin or other drugs in diabetic patients. This research presents fabrication procedures developed to produce pyramidal-shaped microneedles with microchannels that will allow for fluid delivery. The microchannels are etched into the substrate surface of a [100] silicon wafer using inductively coupled plasma etching. After the channel etch a layer of silicon nitride is deposited onto the inner walls of the microchannels and on the surface of the substrate. The nitride on the substrate surface provides the hard mask necessary to etch the microneedles, which are wet etched in a bath of potassium hydroxide (KOH). The selectivity of the KOH on [100] silicon is such that octagonal shaped pyramids are etched into the surface of the wafer. The pyramids are aligned with the previously etched microchannels to allow for needles with channels running through them. This research presents the first needles demonstrated with drug delivery channels running through the robust pyramidal needle shape. In addition to the microchannel/microneedle fabrication procedure, microchannels were developed with inner structures as a method of creating hydrophobic surfaces on the inner walls of the channels. It was found that the channels developed had far too much variability in the diameter to accurately create a measurable reduction in flow; however, a loss coefficient was calculated showing increased flow rates in hydrophobically coated microchannels when hydrophobic structures are incorporated into the channel design. It was also discovered that a hydrophobic coating, typically used to increase flow rates through a channel, can impede flow rate. There was no evidence found to suggest that hydrophobically coated microchannels of this size, with or without structures, will yield higher flow rates than non-coated microchannels.
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A Microanalytical Approach to Understanding the Origin of Cumulate Xenoliths from Mauna Kea, HawaiiPickard, Megan 08 August 2008 (has links) (PDF)
Cumulate xenoliths erupted with alkalic hawaiite lavas from a postshield cinder cone on Mauna Kea, Hawaii include a variety of mafic and ultramafic rock types. Previous studies of major and trace element compositions of minerals in the xenoliths are interpreted to show transitional to alkalic magma parentages from the postshield stage, although any orthopyroxene-bearing xenoliths are considered to have tholeiitic parents. Major element compositions minerals were analyzed using the electron microprobe and trace element compositions of clinopyroxene grains were analyzed by laser ablation inductively coupled plasma mass spectrometry. In this study, major element compositions of clinopyroxene, olivine and plagioclase grains and trace element compositions in clinopyroxene grains in xenoliths lacking orthopyroxene indicate a transitional magma parentage consistant with postshield magmas. Trace element compositions of possible parent magmas of the xenoliths were calculated from clinopyroxene compositions using partition coefficients for basaltic liquids from Hauri et al. (1994). Liquids calculated from the clinopyroxene in the xenoliths were compared to Mauna Kea shield lavas and to the postshield Hamakua and Laupahoehoe units. Chondrite-normalized rare earth element (REE) patterns of liquids calculated from both orthopyroxene-bearing xenoliths and those without orthopyroxene were similar REE patterns of both Mauna Kea postshield tholeitic and alkalic lavas. Liquids from a wehrlite and an olivine gabbronorite have REE patterns similar to tholeiitic shield basalts. To better distinguish the transitional xenolith sources as one of Mauna Kea's two postshield substages, the older, basaltic Hamakua unit or the younger hawaiitic Laupahoehoe unit, variation diagrams compared calculated liquid compositions to Mauna Kea lavas from the shield and postshield stages. Calculated liquid trace element concentrations are similar to those of Hamakua lavas.
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Dinosaurian Faunas of the Cedar Mountain Formation and LA-ICP-MS Detrital Zircon Ages for Three Stratigraphic SectionsMori, Hirotsugu 23 November 2009 (has links) (PDF)
The Cedar Mountain Formation contains the most diverse record of Early Cretaceous dinosaurs in the western hemisphere. However, analyses of its faunas have been hindered because 1) most taxa are based on incomplete/fragmentary materials or incomplete descriptions, 2) most sites and some horizons preserve few taxa, and 3) the stratigraphy and geochronology are poorly understood. To help resolve these stratigraphic and correlation problems U-Pb LA-ICP-MS detrital zircon ages were obtained at significant sites and horizons. These dates indicate all sites at or near the base of the formation are no older than 122 to 124 Ma, thus all basal stratigraphic packages are time equivalent. Detrital zircons coarsely bracket the temporal span of the Ruby Ranch Member between about 115 Ma to 111 Ma while the base of the Mussentuchit Member is dated between 108 to 104 Ma and the top of the member is Cenomanian in age. Multivariate analyses utilizing Simpson and Raup-Crick similarity index and pair-group moving algorithms reveal that formationfs faunas fall into two groups. These groups are compared statistically with European, Asian, and Morrison faunas. Results indicate (1) that there is no close relationship between the Yellow Cat fauna and the Morrison Formation fauna and (2) corroborate long-standing hypotheses that the Yellow Cat fauna has European ties and the Mussentuchit fauna has Asian ties. Detrital zircon LA-ICP-MS U-Pb ages were used in this study to approximate the time of deposition of strata because volcanic ashes are rarely preserved in the formation. The ability to select the youngest crystals in a sample prior to applying analytical methods could substantially reduce the number of crystals and cost required to obtain these dates. To this end, the hypothesis that the most pristine, unabraded crystals should be younger than abraded crystals was tested by imaging detrital zircons via SEM, ranking the crystals by the degree of abrasion, and determining their ages. Results of this study partly corroborate the hypothesis in that there is a correlation between the degree of abrasion and ages – obviously abraded crystals are most likely the oldest while pristine to slightly abraded crystals are usually the youngest in a given sample.
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Ion Transport Behaviors Upstream and Downstream from the Sampling Cone of an Inductively Coupled Plasma Mass SpectrometerMa, Haibin 09 July 2009 (has links) (PDF)
Inductively coupled plasma - mass spectrometry (ICP-MS) is the technique of choice worldwide for trace elemental determinations because of its excellent ionization ability, low detection limits and fast analysis speeds. However, the ICP-MS still suffers from some disadvantages, such as spectral overlap and severe matrix effects. Matrix effects or interferences, partly arise from changes in the analyte transmission through the interfacial region between the ICP and mass spectrometer with changes in sample matrix. Better understanding of the transmission behaviors of analyte through the sampling and skimmer cones will provide the insights needed to alleviate matrix interferences and to improve the interface design between the ICP and mass spectrometer. Laser induced fluorescence is a highly sensitive, non-invasive and element specific detection method. The research herein endeavors to explain the transport behaviors of analytes upstream and downstream from the sampling cone in an ICP-MS. The final goal of this research is to improve the consistency and efficiency with which ions are transported from an ICP source to a mass analyzer. Several issues related to analyte transmission through the sampling and skimmer cones have been explored and discussed in this dissertation. First, it is found that the existence of the sampling cone not only disturbs the local thermodynamic equilibrium of the plasma, but also changes the spatial distributions and number densities of analyte species. Second, it has been verified that the spread of analyte species in the first vacuum stage is mass-dependent and can be explained by ambiploar diffusion theory. Finally, the current research suggests that the transmission efficiencies of the skimmer cone are impacted by the nebulizer flow and first vacuum stage pressure of the ICP-MS. To better elucidate the analyte transport behaviors from the plasma to the ion detector in an ICP-MS, more investigation needs to be carried out. Further research, such as the entire measurements of analyte transmission efficiency through the skimmer cone, the variation of doubly charged ions under different plasma operational conditions, and the functions of argon metastable atoms on analyte ionization inside the plasma will require much additional work.
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Laser-Induced Fluorescence Imaging of Calcium and Barium Ion Beams in the Second Vacuum Stage of a Commercial Inductively Coupled Plasma Mass SpectrometerEdmund, Alisa Jane 24 June 2014 (has links) (PDF)
Inductively coupled plasma-mass spectrometers (ICP-MS) have become the workhorses of many analytical labs over the past few decades. Despite the instruments' high sensitivities and low detection limits there is still a demand for improvements in several aspects of their performance. One area of improvement is in the understanding of "space charge effects" Space charge effects are classified as problems associated with the ion beam. Problems are created when the mutual repulsions of the ions make consistent focusing of the ion beam difficult. This is particularly problematic with samples containing a low concentration analyte contained within a high salt solution matrix, resulting in lower instrument sensitivity and inaccurate results. The research presented here used laser-induced fluorescence (LIF) imaging to characterize the ion beam as it enters the mass analyzer of a commercial ICP-MS. To perform the LIF imaging a laser system with two ring cavities was constructed to frequency double a CW titanium-sapphire laser to the calcium ion transition at 393.4 nm or to the barium ion transition at 455.4 nm. Ion beam images for both elements were taken under different instrument modes and matrix compositions. The same trends in shift and distortion of the barium ion beam with the addition of a lead matrix was observed as in previous experiments with calcium. A shift in the focal point of the ion beams of both elements was also observed in normal sensitivity mode and with the instrument's collisional reaction interface (CRI). This work indicates that a shift in beam focusing is responsible for the change in ion transmission due to changes in matrix composition and instrument modes.
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Localization with Time-of-Flight cameras / Positionering med Time-of-Flight kamerorPettersson, Lucas January 2020 (has links)
Time-of-Flight (ToF) cameras are becoming an increasingly common sensor in smartphones. These sensors are able to produce depth measurements in a grid at a relatively high rate. Using these depth measurements, point-clouds representing the captured scene can be produced. Previous research has been conducted in using ToF or LIDAR images to localize the camera. In this paper, we investigate several methods to localize the camera using point-clouds and surface meshes. Small alterations were made to some of the algorithms but the concepts remain the same. The main algorithms consisted of ICP variants as well as a relatively recent method called Corrective Gradient Refinement (CGR). The results obtained from generated data indicate that some of the methods are applicable for real-time applications, and the position estimates are comparable to those found in previous results. / Time-of-flight (ToF)-kameror blir en allt vanligare sensor i mobiltelefoner. Dessa sensorer kan producera djupmätningar i ett rutnät med relativt hög frekvens. Med hjälp av dessa djupmätningar kan ett punktmoln som representerar den fångade scenen produceras. Tidigare forskning har gjorts med hjälp av ToF- eller LIDAR-bilder för att lokalisera kameran. Här undersöks flera metoder för att lokalisera kameran med hjälp av ett punktmoln och en triangulering av en modell. Algoritmerna bestod till största delen av ICP-varianter samt en relativt ny metod som heter Corrective Gradient Refinement (CGR). Resultaten som erhållits från genererade data indikerar att vissa av metoderna är lämplig för realtidsapplikationer och felet på positioneringen är jämförbart med dem som hittades i tidigare resultat.
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