945 research outputs found
Karsten tube analysis for joint mortar identification in masonry
No full textThe present work examines the Karsten tube penetration test to identify mortar types in existing masonry, for mortars containing air-lime or hydraulic binders. Mortar type identification is e.g. of relevance for the reusability of the fired clay bricks in the masonry, where a hydraulic binder content makes the mortar removal process significantly more difficult. The Karsten tube test makes it possible to make a simple and non-destructive mortar analysis on-site assessing the water absorption of the mortar, via the surface of the mortar joint alone. The present approach considers both the effect of the surrounding bricks and the surface finish of the pointing. Furthermore, the setup masks the brick surface exposed under the Karsten tube to focus the exposure on the mortar. Three different mortar types in existing masonry were tested: air-lime mortar, air-lime/hydraulic lime mortar and air-lime/cement mortar. The results showed linear water absorptions, which were clearly distinguishable for the hydraulic and non-hydraulic binders during the 15-minute tests. The measurement results in the present work document how the Karsten tube penetration test can be used for simple and non-destructive identification of joint mortar types determining whether the masonry was constructed with air-lime mortar or mortar containing hydraulic binders
Parental gender indifference or persistent sex preferences for children at the turn to the 21st century? A reflection on Pollard and Morgan (2002) with reference to the Swedish case
No full textIn their recent ASR article on the sex composition of previous offspring and third births in the US, Pollard and Morgan (2002) argue that changes in the societal gender system - namely increasing opportunities for women - have lead to a decreasing effect of children´s gender on parents´ fertility decisions. If the authors were right in their conclusions, one should expect to find no sex preferences for children in countries with a high level of gender equality. In this reflection, we exploit population register data for the years 1961 to 1999 to examine the Swedish example. Our results show that even in the fairly gender equal Swedish society, a clear preference for one child of each sex has continued to exist until today.
Perov5
No full textPlease consider citing the following two papers:
```
@article{castelli2012new,
title={New cubic perovskites for one-and two-photon water splitting using the computational materials repository},
author={Castelli, Ivano E and Landis, David D and Thygesen, Kristian S and Dahl, S{\o}ren and Chorkendorff, Ib and Jaramillo, Thomas F and Jacobsen, Karsten W},
journal={Energy \& Environmental Science},
volume={5},
number={10},
pages={9034--9043},
year={2012},
publisher={Royal Society of Chemistry}
}
```
```
@article{castelli2012computational,
title={Computational screening of perovskite metal oxides for optimal solar light capture},
author={Castelli, Ivano E and Olsen, Thomas and Datta, Soumendu and Landis, David D and Dahl, S{\o}ren and Thygesen, Kristian S and Jacobsen, Karsten W},
journal={Energy \& Environmental Science},
volume={5},
number={2},
pages={5814--5819},
year={2012},
publisher={Royal Society of Chemistry}
}
```</p
Characteristics and accuracy of large area covering height models
No full textLarge area covering height models are dominantly based on optical and synthetic aperture radar (SAR) space imagery. The vertical accuracy of individual object points determined by automatic matching of optical imagery is in the range of 1.0 ground sampling distance (GSD), but this is not identical to the accuracy of the height model. With the exception of long wavelength SAR data, the P- and L-band, all height models are originally digital surface models (DSM) and not the most often requested digital terrain models (DTM) with the height of the bare ground which have to be generated by filtering. In addition height models are influenced by interpolation, reducing the geometric quality. Large area covering height models are analyzed for their accuracy and characteristics, including the effect of details influenced by the method of determination. The absolute accuracy in addition is affected by the quality of geo-reference, which partly is based on the direct sensor orientation, partly based on ground control points (GCP) or indirectly on other existing height models. The most important influence for the resolution of a height model is the point spacing of the DHM, but details also can be lost by not proper data handling. All height models have lower accuracy in steep terrain, the matching of optical images is influenced by the object contrast, while SAR is affected by layover. By this reason gaps in the height models often are filled with other data causing more heterogeneous character
Characteristics of very high resolution optical satellites for topographic mapping
No full textThe ground resolution of optical satellites now overlaps with the ground resolution of aerial images. The radiometric and geometric quality of the satellite images can be compared with original digital aerial images and is better as corresponding analog photos. Important parameters for the operational handling of the very high resolution satellite images as imaging capacity, revisit time and rotation speed, important for getting stereo pairs and the flexibility of imaging of different areas, and effective image resolution are shown in detail. The reason for changed spectral range of GeoEye-1 and WorldView-2 against preceding systems is explained with its consequences to pan-sharpening. Scene orientation today is not a problem, so approximations are not justified anymore. With the improved possibility of stereoscopic coverage within the orbit, digital elevation models operationally can be generated. For some types of automatic image matching epipolar images are required. Based on images projected to a plane with constant height or even a rough height model a rotation of the satellite images to the base direction is satisfying as quasi epipolar images. The remaining discrepancies against theoretical strict epipolar images are estimated
Foreword to the European journal of remote sensing special issue. Urban remote sensing - challenges and solutions
No full textThis special issue features a collection of ten contributions focusing on urban remote sensing applications
Problems and limitations of satellite image orientation for determination of height models
No full textThe usual satellite image orientation is based on bias corrected rational polynomial coefficients (RPC). The RPC are describing the direct sensor orientation of the satellite images. The locations of the projection centres today are without problems, but an accuracy limit is caused by the attitudes. Very high resolution satellites today are very agile, able to change the pointed area over 200km within 10 to 11 seconds. The corresponding fast attitude acceleration of the satellite may cause a jitter which cannot be expressed by the third order RPC, even if it is recorded by the gyros. Only a correction of the image geometry may help, but usually this will not be done. The first indication of jitter problems is shown by systematic errors of the y-parallaxes (py) for the intersection of corresponding points during the computation of ground coordinates. These y-parallaxes have a limited influence to the ground coordinates, but similar problems can be expected for the x-parallaxes, determining directly the object height. Systematic y-parallaxes are shown for Ziyuan-3 (ZY3), WorldView-2 (WV2), Pleiades, Cartosat-1, IKONOS and GeoEye. Some of them have clear jitter effects. In addition linear trends of py can be seen. Linear trends in py and tilts in of computed height models may be caused by limited accuracy of the attitude registration, but also by bias correction with affinity transformation. The bias correction is based on ground control points (GCPs). The accuracy of the GCPs usually does not cause some limitations but the identification of the GCPs in the images may be difficult. With 2-dimensional bias corrected RPC-orientation by affinity transformation tilts of the generated height models may be caused, but due to large affine image deformations some satellites, as Cartosat-1, have to be handled with bias correction by affinity transformation. Instead of a 2-dimensional RPC-orientation also a 3-dimensional orientation is possible, respecting the object height more as by 2-dimensional orientation. The 3-dimensional orientation showed advantages for orientation based on a limited number of GCPs, but in case of poor GCP distribution it may cause also negative effects. For some of the used satellites the bias correction by affinity transformation showed advantages, but for some other the bias correction by shift was leading to a better levelling of the generated height models, even if the root mean square (RMS) differences at the GCPs were larger as for bias correction by affinity transformation. The generated height models can be analyzed and corrected with reference height models. For the used data sets accurate reference height models are available, but an analysis and correction with the free of charge available SRTM digital surface model (DSM) or ALOS World 3D (AW3D30) is also possible and leads to similar results. The comparison of the generated height models with the reference DSM shows some height undulations, but the major accuracy influence is caused by tilts of the height models. Some height model undulations reach up to 50% of the ground sampling distance (GSD), this is not negligible but it cannot be seen not so much at the standard deviations of the height. In any case an improvement of the generated height models is possible with reference height models. If such corrections are applied it compensates possible negative effects of the type of bias correction or 2-dimensional orientations against 3-dimensional handling
Sigmund Freud contra Helga Grebing - Kommentierende Anmerkungen zu den Beiträgen von Max Bloch, Karsten Rudolph, Meik Woyke und Walter Mühlhausen
No full textConcentrating on the contributions of Max Bloch, Karsten Rudolph, Meik Woyke and Walter Mühlhausen the author sums up the contributions of this volume in order to reflect on the current state of research in the field of the historiography of biographies of leading social democrats. He discusses remaining lacunae in research and develops perspectives for future research
Castelli Perovskites Data
No full text18,928 perovskites generated with ABX combinatorics, calculating gbllsc
band gap and pbe structure, and also reporting absolute band edge
positions and heat of formation. Available as Monty Encoder encoded JSON and CSV files. The recommended
access method is through the matminer Python package using the datasets
module.Note on citations: If you found this dataset useful and would like to
cite it in your work, please be sure to cite its original sources below
rather than or in addition to this page.Dataset is described in the following:Ivano E. Castelli, David D. Landis, Kristian S. Thygesen, Søren Dahl, Ib Chorkendorff, Thomas F. Jaramillo and Karsten W. Jacobsen (2012) New cubic perovskites for one- and two-photon water splitting using the computational materials repository. Energy Environ. Sci., 2012,5, 9034-9043 https://doi.org/10.1039/C2EE22341D</div
Two Men and Nine Years: Contribution of Karsten Jacobsen and Gürcan Büyüksalih to Photogrammetry and Remote Sensing Activities of Department of Geomatics Engineering at Zonguldak Bülent Ecevit University
No full textThe millennium witnessed the development of high resolution remote sensing technology and its role in the geospatial information extraction. These developments required the photogrammetric evaluation of these images. Thanks to Dr. Gürcan Büyüksalih’s attending to the Department of Geomatics Engineering at Zonguldak Bülent Ecevit University at the beginning of 1998, the education and research studies were started initiated under the guidance of a full-faculty member of the Department. After three years of preparation, a bilateral international project leading in its field was started in cooperation with Dr. Karsten Jacobsen. This paper reviews the contribution of two men to a wide range of photogrammetry and remote sensing activities in the Department of Geomatics Engineering at Zonguldak Bülent Ecevit University between 1998 and 2007. These studies involved not only the high resolution remote sensing images such as SPOT-5, IRS-1C, IKONOS, QuickBird, OrbView-3, Kompsat-1, Landsat but also the optical analogue images such as TK-350, KVR-1000 and MOMS-2P, and microwave data such as SRTM and JERS in terms of geometric analysis, georeferencing accuracy assessment, DSM/DEM generation and validation, and information content for topographic mapping. Thanks to this bilateral co-operation, the concept of mapping from space was developed and supported by many international scientists, making a very important contribution to the development of advanced remote sensing. These research activities were extended by bilateral Erasmus agreements, bilateral academic visits, two training courses which were the first in Türkiye, participation in various national and international scientific events, organisation of an ISPRS workshop and official duties in ISPRS working group
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