The Experts below are selected from a list of 44466 Experts worldwide ranked by ideXlab platform
Rainer Horn - One of the best experts on this subject based on the ideXlab platform.
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shrinkage characteristics of boulder marl as sustainable mineral liner material for landfill capping systems
Sustainability, 2018Co-Authors: Steffen Beckbroichsitter, Horst H Gerke, Rainer HornAbstract:The soil shrinkage behavior of mineral substrates needs to be considered for engineering long-term durable mineral liners of landfill capping systems. For this purpose, a novel three-dimensional laser Scanning Device was coupled with (a) a mathematical-empirical model and (b) in-situ tensiometer measurements as a combined approach to simultaneously determine the shrinkage behavior of a boulder marl, installed as top and bottom liner material at the Rastorf landfill (Northern Germany). The shrinkage behavior, intensity, and geometry were determined during a drying experiment with undisturbed soil cores (100 cm3) from two soil pits; the actual in-situ shrinkage was also determined in 0.2, 0.5, 0.8, and 1.0 m depth by pressure transducer tensiometer measurements during a four-year period. The volume shrinkage index was used to describe the pore size dependent shrinkage tendency and it was classified as low (4.9%) for the bottom liner. The in-situ matric potentials in the bottom liner ranged between −100 and −150 hPa, even during drier periods, thus, the previously highest observed drying range (pre-shrinkage stress) with values below −500 hPa and −1000 hPa was not exceeded. Therefore, the hydraulic stability of the bottom liner was given.
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suitability of boulder marl and marsh clay as sealing substrates for landfill capping systems a practical comparison
Geosciences, 2018Co-Authors: Steffen Beckbroichsitter, Horst H Gerke, Rainer HornAbstract:The effects of compaction on soil shrinkage behavior need to be considered for engineering long-term durable mineral liners of landfill capping systems. For this purpose, a new three-dimensional laser Scanning Device was coupled with a mathematical-empirical model to simultaneously determine the shrinkage behavior of a boulder marl (bm) and a marsh clay (mc). Therefore, both materials were precompacted in 200 soil cores (100 cm3) on the basis of the Proctor test results with five different degrees of compaction (bm1-bm5; mc1-mc5). Thus, the shrinkage behavior, intensity, and tendency were determined during a standardized drying experiment. The volume shrinkage index was used to describe the pore size dependent shrinkage tendency and was classified as high to very high (11.3–17.7%) for the marsh clay and medium (5.3–9.2%) for the boulder marl. Additionally, only the boulder marl (bm2), compacted up to 88% of Proctor density, could be installed as landfill bottom liner in drier locations if the local matric potentials did not exceed the previously highest observed drying range (i.e. values below −300 hPa), to avoid crack formation and generation.
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Suitability of Boulder Marl and Marsh Clay as Sealing Substrates for Landfill Capping Systems—A Practical Comparison
MDPI AG, 2018Co-Authors: Steffen Beck-broichsitter, Horst H Gerke, Rainer HornAbstract:The effects of compaction on soil shrinkage behavior need to be considered for engineering long-term durable mineral liners of landfill capping systems. For this purpose, a new three-dimensional laser Scanning Device was coupled with a mathematical-empirical model to simultaneously determine the shrinkage behavior of a boulder marl (bm) and a marsh clay (mc). Therefore, both materials were precompacted in 200 soil cores (100 cm3) on the basis of the Proctor test results with five different degrees of compaction (bm1-bm5; mc1-mc5). Thus, the shrinkage behavior, intensity, and tendency were determined during a standardized drying experiment. The volume shrinkage index was used to describe the pore size dependent shrinkage tendency and was classified as high to very high (11.3–17.7%) for the marsh clay and medium (5.3–9.2%) for the boulder marl. Additionally, only the boulder marl (bm2), compacted up to 88% of Proctor density, could be installed as landfill bottom liner in drier locations if the local matric potentials did not exceed the previously highest observed drying range (i.e. values below −300 hPa), to avoid crack formation and generation
Roy G. Geronemus - One of the best experts on this subject based on the ideXlab platform.
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skin resurfacing of fine to deep rhytides using a char free carbon dioxide laser in 47 patients
Dermatologic Surgery, 1995Co-Authors: Heidi A Waldorf, Arielle N B Kauvar, Roy G. GeronemusAbstract:BACKGROUND. Recent advances in carbon dioxide (CO 2 ) laser technology have resulted in the development of lasers that can precisely remove thin layers of skin with minimal thermal damage to the surrounding tissue. These lasers rely on rapid pulsing or Scanning of the laser beam. The effects of these lasers are predictable and reproducible, making them ideal for skin resurfacing. Clinical results have been promising, however, to date, no published series exist. OBJECTIVE. To evaluate the effectiveness and side effect profile of laser resurfacing utilizing a CO 2 laser with a Scanning Device, and make recommendations for patient selection and treatment protocol. METHODS. Patients with perioral, periorbital, and glabellar rhytides were treated with a CO 2 laser with a Scanning Device. Utilizing chart review and photographic evaluation, patients treated between November 1994 and April 1995 were retrospectively evaluated for effectiveness of therapy, healing time, and complication rates. RESULTS. A total of 47 patients were evaluated. Photographic evaluation or chart review revealed good to excellent cosmetic results in all anatomic areas studied. All patients experienced posttreatment erythema lasting 1-6 months. Other minor complications were limited to contact dermatitis to topical preparations, transient postinflammatory hyperpigmentation, and milia formation. One patient experienced a primary herpes simplex virus infection during reepithelialization and required intravenous therapy. Minor focal atrophy was seen in one patient. No hypertrophic scarring or permanent pigmentation changes were seen. CONCLUSION. A CO 2 laser system with a Scanning beam can effectively and safely improve or remove glabellar, perioral, and periorbital rhytides.
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Dye laser treatment of port-wine stains: Comparison of the continuous-wave dye laser with a robotized Scanning Device and the pulsed dye laser☆
Journal of the American Academy of Dermatology, 1995Co-Authors: Jeffrey S. Dover, Roy G. Geronemus, Robert S. Stern, Deirdre O'hare, Kenneth A. ArndtAbstract:Abstract Background: Despite good results in the treatment of most port-wine stains (PWS) with continuous-wave visible-light lasers, light PWS and those in certain locations respond less favorably and have a higher risk of scarring. Robotized Scanning Devices such as the Hexascan Device have been developed for continuous-wave laser sources to produce greater target specificity, to increase reproducibility of results, and to decrease the incidence of adverse effects. Objective: The purpose of this study was to compare the effects of the same wavelength of light (585 nm) on test sites within PWS with the flashlamp-pumped pulsed dye laser and a continuous-wave tunable dye laser scanned through a Hexascan robotized Scanning Device. Methods: Two adjacent, noncontiguous sites within PWS were treated in 29 patients, one site with the flashlamp-pumped pulsed dye laser and the other with an argon-pumped continuous-wave tunable dye laser affixed to a Hexascan Device. Results: Twenty-eight patients completed the study. The pulsed dye laser was found to be superior to the continuous-wave dye laser with the Hexascan Device in 45% of patients, whereas the continuous-wave tunable dye laser with the Hexascan Device was considered superior in 15%. There was no difference in the remaining 40%. Undesirable side effects were infrequent with both treatments. There was no significant difference in hypopigmentation or atrophic and hypertrophic scarring, but hyperpigmentation was more frequent with the continuous-wave dye laser with the Hexascan Device. Conclusion: Both the pulsed dye laser and continuous tunable-wave dye laser with the Hexascan Device produce slight lightening after one treatment. The pulsed dye laser produces slightly greater lightening than the continuous-wave tunable dye laser with the Hexascan Device 6 weeks after treatment of test areas within PWS in 40% of those treated. It also produced slightly less hypopigmentation and hyperpigmentation.
Kenneth A. Arndt - One of the best experts on this subject based on the ideXlab platform.
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Dye laser treatment of port-wine stains: Comparison of the continuous-wave dye laser with a robotized Scanning Device and the pulsed dye laser☆
Journal of the American Academy of Dermatology, 1995Co-Authors: Jeffrey S. Dover, Roy G. Geronemus, Robert S. Stern, Deirdre O'hare, Kenneth A. ArndtAbstract:Abstract Background: Despite good results in the treatment of most port-wine stains (PWS) with continuous-wave visible-light lasers, light PWS and those in certain locations respond less favorably and have a higher risk of scarring. Robotized Scanning Devices such as the Hexascan Device have been developed for continuous-wave laser sources to produce greater target specificity, to increase reproducibility of results, and to decrease the incidence of adverse effects. Objective: The purpose of this study was to compare the effects of the same wavelength of light (585 nm) on test sites within PWS with the flashlamp-pumped pulsed dye laser and a continuous-wave tunable dye laser scanned through a Hexascan robotized Scanning Device. Methods: Two adjacent, noncontiguous sites within PWS were treated in 29 patients, one site with the flashlamp-pumped pulsed dye laser and the other with an argon-pumped continuous-wave tunable dye laser affixed to a Hexascan Device. Results: Twenty-eight patients completed the study. The pulsed dye laser was found to be superior to the continuous-wave dye laser with the Hexascan Device in 45% of patients, whereas the continuous-wave tunable dye laser with the Hexascan Device was considered superior in 15%. There was no difference in the remaining 40%. Undesirable side effects were infrequent with both treatments. There was no significant difference in hypopigmentation or atrophic and hypertrophic scarring, but hyperpigmentation was more frequent with the continuous-wave dye laser with the Hexascan Device. Conclusion: Both the pulsed dye laser and continuous tunable-wave dye laser with the Hexascan Device produce slight lightening after one treatment. The pulsed dye laser produces slightly greater lightening than the continuous-wave tunable dye laser with the Hexascan Device 6 weeks after treatment of test areas within PWS in 40% of those treated. It also produced slightly less hypopigmentation and hyperpigmentation.
Zetek Miroslav - One of the best experts on this subject based on the ideXlab platform.
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Degradace brusného kotouče při broušení cermetových materiálů a její vliv na proces broušení Degradace brusného kotouče při broušení cermetových materiálů a její vliv na proces broušení
Univerzita J. E. Purkyně, 2019Co-Authors: Bakša Tomáš, Hronek Ondřej, Adámek Pavel, Zetek MiroslavAbstract:Tato publikace se zabývá experimentálním broušením cermetových materiálů. Dva různé cermetové materiály od různých dodavatelů byly broušeny za konstantních podmínek pomocí diamantového brusného kotouče. Hlavním cílem bylo určit vliv broušení na degradaci brusného kotouče a změny v procesu broušení. Oba cermety byly broušeny stejnou strategií a při stejném počtu přejezdů. Brusný kotouč byl během broušení analyzován pomocí opticko-skenovacího zařízení kvůli zjištění změn na povrchu kotouče. Rostoucí množství odebraného materiálu při broušení vedlo k zanášení a opotřebení brusného kotouče. Broušení bylo provedeno bez průběžného orovnávání a oživování brusného kotouče. Degradace brusného kotouče měla velký vliv na proces broušení ve smyslu zatížení vřetene stroje. Pomocí opticko-skenovacího zařízení byla rovněž měřena i drsnost povrchu po broušení. Výsledky této práce budou použity při dalším výzkumu v oblasti broušení cermetu.This article deals with the experimental grinding of cermet materials. Two types of cermet materials from different suppliers were ground under constant grinding conditions using a diamond grinding wheel. The main aim was to determine the influence of the grinding on the degradation of the grinding wheel and changes in the grinding process. Both types of cermet were ground with the same strategy and the same number of passes. The grinding wheel was analysed during grinding using an optical Scanning Device to observe the changes on the grinding wheel surface. Clogging and wear of the grinding wheel occurred on the surface as the amount of material removed increased. All grinding tests were carried out without dressing or truing of the grinding wheel. Degradation of the grinding wheel had a big influence on the grinding process in terms of the spindle load during grinding. The roughness of the ground surface was also measured using the optical Scanning Device. The results from this work will be used for further research of cermet grinding
Kwan H Lee - One of the best experts on this subject based on the ideXlab platform.
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automated laser Scanning system for reverse engineering and inspection
International Journal of Machine Tools & Manufacture, 2002Co-Authors: Seokbae Son, Hyunpung Park, Kwan H LeeAbstract:Recently, laser scanners have been used more often for inspection and reverse engineering in industry, such as for motors, electronic products, dies and molds. However, due to the lack of efficient Scanning software, laser scanners are usually manually operated. Therefore, the tasks that involve inspection and reverse engineering processes are very expensive. In this research, we propose an automated measuring system for parts having a freeform surface. In order to automate a measuring process, appropriate hardware system as well as software modules are required. The hardware system consists of a laser Scanning Device and setup fixtures that can provide proper location and orientation for the part to be measured. The software modules generate optimal scan plans so that the Scanning operation can be performed accordingly. In the scan planning step, various Scanning parameters are considered in the generation of optimal scan paths, such as the view angle, depth of field, the length of the stripe, and occlusion. In the Scanning step, the generated scan plans are downloaded to the industrial laser scanner and the point data are captured automatically. The measured point data sets are registered automatically and the quality of point data is evaluated by checking the difference between the CAD model and the measured data. To demonstrate an automated measuring system, a motorized rotary table with two degrees of freedom and a CNC-type laser scanner with four degrees of freedom are used.
