Ptak-Fix, Thomas

[["dc.bibliographiccitation.firstpage","1533"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Water"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Yang, Huichen"],["dc.contributor.author","Hu, Rui"],["dc.contributor.author","Qiu, Pengxiang"],["dc.contributor.author","Liu, Quan"],["dc.contributor.author","Xing, Yixuan"],["dc.contributor.author","Tao, Ran"],["dc.contributor.author","Ptak, Thomas"],["dc.date.accessioned","2021-04-14T08:25:00Z"],["dc.date.available","2021-04-14T08:25:00Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.3390/w12061533"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/17433"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/81493"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.notes.intern","Merged from goescholar"],["dc.publisher","MDPI"],["dc.relation.eissn","2073-4441"],["dc.rights","CC BY 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by/4.0/"],["dc.title","Application of Wavelet De-Noising for Travel-Time Based Hydraulic Tomography"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","S0022169422002530"],["dc.bibliographiccitation.firstpage","127678"],["dc.bibliographiccitation.journal","Journal of Hydrology"],["dc.bibliographiccitation.volume","609"],["dc.contributor.author","Xing, Yixuan"],["dc.contributor.author","Liu, Quan"],["dc.contributor.author","Hu, Rui"],["dc.contributor.author","Gu, Hongbiao"],["dc.contributor.author","Taherdangkoo, Reza"],["dc.contributor.author","Yang, Huichen"],["dc.contributor.author","Ptak, Thomas"],["dc.date.accessioned","2022-06-01T09:40:19Z"],["dc.date.available","2022-06-01T09:40:19Z"],["dc.date.issued","2022"],["dc.identifier.doi","10.1016/j.jhydrol.2022.127678"],["dc.identifier.pii","S0022169422002530"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/108698"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-572"],["dc.relation.issn","0022-1694"],["dc.rights.uri","https://www.elsevier.com/tdm/userlicense/1.0/"],["dc.title","A general numerical model for water level response to harmonic disturbances in aquifers considering wellbore effects"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","57"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Grundwasser"],["dc.bibliographiccitation.lastpage","67"],["dc.bibliographiccitation.volume","17"],["dc.contributor.author","Brauchler, Ralf"],["dc.contributor.author","Hu, Rui"],["dc.contributor.author","Hu, Linwei"],["dc.contributor.author","Ptak, Thomas"],["dc.date.accessioned","2018-11-07T09:09:55Z"],["dc.date.available","2018-11-07T09:09:55Z"],["dc.date.issued","2012"],["dc.description.abstract","In this study the potential of a hydraulic travel-time based inversion approach with analytical solutions for the evaluation of short term pumping tests is assessed. The data base comprises measurements from short-term pumping tests performed in a sand and gravel aquifer using a tomographic measurement array. The evaluation, which is based on an analytical solution, has shown that it is not possible to delimit aquifer zones with different hydraulic properties. The comparison with multi-level slug tests has revealed that the pumping test results are dominated by a zone with a relatively high hydraulic conductivity located close to the bottom of the aquifer. This finding is surprising due to the short pumping time of 200 seconds and due to the hydraulically isolated pumping and observation intervals. The travel-time based inversion, however, allows the reconstruction of vertical and lateral changes in hydraulic diffusivity, between pumping and observation wells, with a high resolution."],["dc.identifier.doi","10.1007/s00767-011-0185-6"],["dc.identifier.isi","000304398800002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26383"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Heidelberg"],["dc.relation.issn","1430-483X"],["dc.title","Investigation of hydraulic parameters in unconsolidated sediments: a comparison of methods"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","909"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Water"],["dc.bibliographiccitation.volume","11"],["dc.contributor.author","Qiu, Pengxiang"],["dc.contributor.author","Hu, Rui"],["dc.contributor.author","Hu, Linwei"],["dc.contributor.author","Liu, Quan"],["dc.contributor.author","Xing, Yixuan"],["dc.contributor.author","Yang, Huichen"],["dc.contributor.author","Qi, Junjie"],["dc.contributor.author","Ptak, Thomas"],["dc.date.accessioned","2019-07-09T11:51:19Z"],["dc.date.available","2019-07-09T11:51:19Z"],["dc.date.issued","2019"],["dc.description.abstract","Travel time based hydraulic tomography is a technique for reconstructing the spatial distribution of aquifer hydraulic properties (e.g., hydraulic di usivity). Simultaneous Iterative Reconstruction Technique (SIRT) is a widely used algorithm for travel time related inversions. Due to the drawbacks of SIRT implementation in practice, a modified SIRT with Cimmino iteration (SIRT-Cimmino) is proposed in this study. The incremental correction is adjusted, and an iteration-dependent relaxation parameter is introduced. These two modifications enable an appropriate speed of convergence, and the stability of the inversion process. Furthermore, a new result selection rule is suggested to determine the optimal iteration step and its corresponding result. SIRT-Cimmino and SIRT are implemented and verified by using two numerical aquifer models with di erent predefined (“true”) di usivity distributions, where high di usivity zones are embedded in a homogenous low di usivity field. Visual comparison of the reconstructions shows that the reconstruction based on SIRT-Cimmino demonstrates the aquifer’s hydraulic features better than the conventional SIRT algorithm. Root mean square errors and correlation coe cients are also used to quantitatively evaluate the performance of the inversion. The reconstructions based on SIRT-Cimmino are found to preserve the connectivity of the high di usivity zones and to provide a higher structural similarity to the “true” distribution."],["dc.identifier.doi","10.3390/w11050909"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16101"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59923"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.publisher","MDPI"],["dc.relation.eissn","2073-4441"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","550"],["dc.title","A Numerical Study on Travel Time Based Hydraulic Tomography Using the SIRT Algorithm with Cimmino Iteration"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Water Resources Research"],["dc.bibliographiccitation.volume","56"],["dc.contributor.author","Liu, Quan"],["dc.contributor.author","Hu, Linwei"],["dc.contributor.author","Bayer, Peter"],["dc.contributor.author","Xing, Yixuan"],["dc.contributor.author","Qiu, Pengxiang"],["dc.contributor.author","Ptak, Thomas"],["dc.contributor.author","Hu, Rui"],["dc.date.accessioned","2021-04-14T08:31:52Z"],["dc.date.available","2021-04-14T08:31:52Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.1029/2020WR027155"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/83735"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.eissn","1944-7973"],["dc.relation.issn","0043-1397"],["dc.title","A Numerical Study of Slug Tests in a Three‐Dimensional Heterogeneous Porous Aquifer Considering Well Inertial Effects"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","S0022169422003262"],["dc.bibliographiccitation.firstpage","127751"],["dc.bibliographiccitation.journal","Journal of Hydrology"],["dc.bibliographiccitation.volume","609"],["dc.contributor.author","Liu, Quan"],["dc.contributor.author","Hu, Rui"],["dc.contributor.author","Hu, Linwei"],["dc.contributor.author","Xing, Yixuan"],["dc.contributor.author","Qiu, Pengxiang"],["dc.contributor.author","Yang, Huichen"],["dc.contributor.author","Fischer, Steffen"],["dc.contributor.author","Ptak, Thomas"],["dc.date.accessioned","2022-06-01T09:40:20Z"],["dc.date.available","2022-06-01T09:40:20Z"],["dc.date.issued","2022"],["dc.identifier.doi","10.1016/j.jhydrol.2022.127751"],["dc.identifier.pii","S0022169422003262"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/108699"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-572"],["dc.relation.issn","0022-1694"],["dc.rights.uri","https://www.elsevier.com/tdm/userlicense/1.0/"],["dc.title","Investigation of hydraulic properties in fractured aquifers using cross-well travel-time based thermal tracer tomography: Numerical and field experiments"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","128148"],["dc.bibliographiccitation.journal","Journal of Hydrology"],["dc.bibliographiccitation.volume","612"],["dc.contributor.author","Yang, Huichen"],["dc.contributor.author","Liu, Quan"],["dc.contributor.author","Hu, Rui"],["dc.contributor.author","Ptak, Thomas"],["dc.contributor.author","Taherdangkoo, Reza"],["dc.contributor.author","Liu, Yuxi"],["dc.contributor.author","Noubactep, Chicgoua"],["dc.date.accessioned","2022-12-01T08:30:39Z"],["dc.date.available","2022-12-01T08:30:39Z"],["dc.date.issued","2022"],["dc.description.sponsorship"," http://dx.doi.org/10.13039/501100002855 Ministry of Science and Technology of the People's Republic of China"],["dc.identifier.doi","10.1016/j.jhydrol.2022.128148"],["dc.identifier.pii","S0022169422007223"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/117945"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-621"],["dc.relation.issn","0022-1694"],["dc.rights.uri","https://www.elsevier.com/tdm/userlicense/1.0/"],["dc.title","Numerical case studies on long-term effectiveness of metallic iron based permeable reactive barriers: Importance of porosity heterogeneity of the barrier"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]