TY - JOUR A1 - Dachwald, Bernd A1 - McDonald, Malcolm A1 - McInnes, Colin R. A1 - Mengali, Giovanni T1 - Impact of Optical Degradation on Solar Sail Mission Performance JF - Journal of Spacecraft and Rockets. 44 (2007), H. 4 Y1 - 2007 SN - 0022-4650 N1 - 2. ISSN: 1533-6794 SP - 740 EP - 749 ER - TY - JOUR A1 - Nguyen, Nhu Huynh A1 - Duong, Minh Tuan A1 - Tran, Thanh Ngoc A1 - Pham, Phu Tinh A1 - Grottke, O. A1 - Tolba, R. A1 - Staat, Manfred T1 - Influence of a freeze–thaw cycle on the stress–stretch curves of tissues of porcine abdominal organs JF - Journal of Biomechanics N2 - The paper investigates both fresh porcine spleen and liver and the possible decomposition of these organs under a freeze–thaw cycle. The effect of tissue preservation condition is an important factor which should be taken into account for protracted biomechanical tests. In this work, tension tests were conducted for a large number of tissue specimens from twenty pigs divided into two groups of 10. Concretely, the first group was tested in fresh state; the other one was tested after a freeze-thaw cycle which simulates the conservation conditions before biomechanical experiments. A modified Fung model for isotropic behavior was adopted for the curve fitting of each kind of tissues. Experimental results show strong effects of the realistic freeze–thaw cycle on the capsule of elastin-rich spleen but negligible effects on the liver which virtually contains no elastin. This different behavior could be explained by the autolysis of elastin by elastolytic enzymes during the warmer period after thawing. Realistic biomechanical properties of elastin-rich organs can only be expected if really fresh tissue is tested. The observations are supported by tests of intestines. KW - Autolysis KW - Decomposition KW - Freeze–thaw process KW - Spleen KW - Liver Y1 - 2012 U6 - https://doi.org/10.1016/j.jbiomech.2012.07.008 SN - 1873-2380 VL - 45 IS - 14 SP - 2382 EP - 2386 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Staat, Manfred A1 - Trenz, Eva A1 - Lohmann, Philipp A1 - Frotscher, Ralf A1 - Klinge, Uwe A1 - Tabaza, Ruth A1 - Kirschner-Hermanns, Ruth T1 - New measurements to compare soft tissue anchoring systems in pelvic floor surgery JF - Journal of Biomedical Materials Research Part B: Applied Biomaterials N2 - Suburethral slings as well as different meshes are widely used treating stress urinary incontinence and prolaps in women. With the development of MiniSlings and special meshes using less alloplastic material anchorage systems become more important to keep devices in place and to put some tension especially on the MiniSlings. To date, there are many different systems of MiniSlings of different companies on the market which differ in the structure of the used meshes and anchors. A new objective measurement method to compare different properties of MiniSling systems (mesh and anchor) is presented in this article. Ballistic gelatine acts as soft tissue surrogate. Significant differences in parameters like pull-out strength of anchors or shrinkage of meshes under loading conditions have been determined. The form and size of the anchors as well as the structural stability of the meshes are decisive for a proper integration. The tested anchorings sytems showed markedly different mechanical function at their respective load bearing capacity. As the stable fixation of the device in tissue is a prerequisite for a permanet reinforcement, the proposed test system permits further optimisation of anchor and mesh devices to improve the success of the surgical treatment Y1 - 2012 U6 - https://doi.org/10.1002/jbm.b.32654 SN - 1552-4981 VL - 100B IS - 4 SP - 924 EP - 933 PB - Wiley CY - Hoboken, NJ ER - TY - JOUR A1 - Konstantinidis, Konstantinos A1 - Flores Martinez, Claudio A1 - Dachwald, Bernd A1 - Ohndorf, Andreas A1 - Dykta, Paul A1 - Bowitz, Pascal A1 - Rudolph, Martin A1 - Digel, Ilya A1 - Kowalski, Julia A1 - Voigt, Konstantin A1 - Förstner, Roger T1 - A lander mission to probe subglacial water on Saturn's moon enceladus for life JF - Acta astronautica Y1 - 2015 SN - 1879-2030 (E-Journal); 0094-5765 (Print) VL - Vol. 106 SP - 63 EP - 89 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Novacek, V. A1 - Tran, Thanh Ngoc A1 - Klinge, U. A1 - Tolba, R. H. A1 - Staat, Manfred A1 - Bronson, D. G. A1 - Miesse, A. M. A1 - Whiffen, J. A1 - Turquier, F. T1 - Finite element modelling of stapled colorectal end-to-end anastomosis : Advantages of variable height stapler design JF - Journal of Biomechanics N2 - The impact of surgical staplers on tissues has been studied mostly in an empirical manner. In this paper, finite element method was used to clarify the mechanics of tissue stapling and associated phenomena. Various stapling modalities and several designs of circular staplers were investigated to evaluate the impact of the device on tissues and mechanical performance of the end-to-end colorectal anastomosis. Numerical simulations demonstrated that a single row of staples is not adequate to resist leakage due to non-linear buckling and opening of the tissue layers between two adjacent staples. Compared to the single staple row configuration, significant increase in stress experienced by the tissue at the inner staple rows was observed in two and three rows designs. On the other hand, adding second and/or third staple row had no effect on strain in the tissue inside the staples. Variable height design with higher staples in outer rows significantly reduced the stresses and strains in outer rows when compared to the same configuration with flat cartridge. KW - Variable height stapler design KW - Anastomotic leakage KW - Finite element modelling KW - End-to-end colorectal anastomosis KW - Surgical staplers Y1 - 2012 U6 - https://doi.org/10.1016/j.jbiomech.2012.07.021 SN - 1873-2380 VL - 45 IS - 115 SP - 2693 EP - 2697 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Staat, Manfred T1 - Direct finite element route for design-by-analysis of pressure components N2 - In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion. KW - Einspielen KW - Plastizität KW - Deformation KW - Analytischer Zulaessigkeitsnachweis KW - Einspiel-Analyse KW - fortschreitende plastische Deformation KW - alternierend Verformbarkeit KW - Einspiel-Kriterium KW - Design-by-analysis KW - Shakedown analysis KW - Progressive plastic deformation KW - Alternating plasticity KW - Shakedown criterion Y1 - 2005 ER - TY - JOUR A1 - Hackl, Michael A1 - Wegmann, Kilian A1 - Kahmann, Stephanie Lucina A1 - Heinze, Nicolai A1 - Staat, Manfred A1 - Neiss, Wolfram F. A1 - Scaal, Martin A1 - Müller, Lars P. T1 - Radial shortening osteotomy reduces radiocapitellar contact pressures while preserving valgus stability of the elbow JF - Knee Surgery, Sports Traumatology, Arthroscopy Y1 - 2017 U6 - https://doi.org/10.1007/s00167-017-4468-z SN - 1433-7347 VL - 25 IS - 7 SP - 2280 EP - 2288 PB - Springer CY - Berlin ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Probabilistic limit and shakedown problems JF - Numerical Methods for Limit and Shakedown Analysis. Deterministic and Probabilistic Approach. NIC Series Vol. 15 / Ed. by Staat, M; Heitzer, M. Y1 - 2003 SN - 3-00-010001-6 SP - 217 EP - 268 PB - John von Neumann Institute for Computing (NIC) CY - Jülich ER - TY - JOUR A1 - Dachwald, Bernd A1 - Ulamec, Stephan A1 - Postberg, Frank A1 - Sohl, Frank A1 - Vera, Jean-Pierre de A1 - Christoph, Waldmann A1 - Lorenz, Ralph D. A1 - Hellard, Hugo A1 - Biele, Jens A1 - Rettberg, Petra T1 - Key technologies and instrumentation for subsurface exploration of ocean worlds JF - Space Science Reviews N2 - In this chapter, the key technologies and the instrumentation required for the subsurface exploration of ocean worlds are discussed. The focus is laid on Jupiter’s moon Europa and Saturn’s moon Enceladus because they have the highest potential for such missions in the near future. The exploration of their oceans requires landing on the surface, penetrating the thick ice shell with an ice-penetrating probe, and probably diving with an underwater vehicle through dozens of kilometers of water to the ocean floor, to have the chance to find life, if it exists. Technologically, such missions are extremely challenging. The required key technologies include power generation, communications, pressure resistance, radiation hardness, corrosion protection, navigation, miniaturization, autonomy, and sterilization and cleaning. Simpler mission concepts involve impactors and penetrators or – in the case of Enceladus – plume-fly-through missions. Y1 - 2020 U6 - https://doi.org/10.1007/s11214-020-00707-5 SN - 1572-9672 N1 - Corresponding author: Bernd Dachwald VL - 216 IS - Art. 83 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Hackl, Michael A1 - Kahmann, Stephanie Lucina A1 - Wegmann, Kilian A1 - Ries, Christian A1 - Staat, Manfred A1 - Müller, Lars-Peter T1 - Shortening osteotomy of the proximal radius — a treatment option for isolated osteoarthritis of the lateral column of the elbow joint? JF - Knee surgery, sports traumatology, arthroscopy N2 - Treatment of posttraumatic osteoarthritis of the radial column of the elbow joint remains a challenging yet common issue. While partial joint replacement leads to high revision rates, radial head excision has shown to severely increase joint instability. Shortening osteotomy of the radius could be an option to decrease the contact pressure of the radiohumeral joint and thereby pain levels without causing valgus instability. Hence, the aim of this biomechanical study was to evaluate the effects of radial shortening on axial load distribution and valgus stability of the elbow joint. Y1 - 2016 U6 - https://doi.org/10.1007/s00167-016-4080-7 SN - 0942-2056 VL - Volume 24 IS - Supplement 1 SP - 128 EP - 129 PB - Springer CY - Berlin ER - TY - JOUR A1 - Staat, Manfred T1 - Some Achievements of the European Project LISA for FEM Based Limit and Shakedown Analysis JF - Computational mechanics : developments and applications, 2002 : presented at the 2002 ASME Pressure Vessels and Piping Conference, Vancouver, British Columbia, Canada, August 5 - 9. / Badie, N. [ed] Y1 - 2002 SN - 0791846520 N1 - Serie PVP ; vol. 441. SP - 177 EP - 185 PB - American Society of Mechanical Engineers CY - New York ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. A1 - Reiners, H. A1 - Schubert, F. T1 - Shakedown and ratchetting under tension–torsion loadings: analysis and experiments JF - Nuclear Engineering and Design. 225 (2003), H. 1 Y1 - 2003 SN - 0029-5493 SP - 11 EP - 26 ER - TY - JOUR A1 - Dachwald, Bernd A1 - Wi, Bong T1 - Solar Sail Kinetic Energy Impactor Trajectory Optimization for an Asteroid-Deflection Mission JF - Journal of Spacecraft and Rockets. 44 (2007), H. 4 Y1 - 2007 SN - 0022-4650 N1 - 2. ISSN: 1533-6794 SP - 755 EP - 764 ER - TY - JOUR A1 - Dachwald, Bernd T1 - Minimum Transfer Times for Nonperfectly Reflecting Solar Sailcraft JF - Journal of Spacecraft and Rockets. 41 (2004), H. 4 Y1 - 2004 SN - 0022-4650 N1 - 2. ISSN: 1533-6794 SP - 693 EP - 695 ER - TY - JOUR A1 - Eschweiler, J. A1 - Laack, Walter van A1 - Staat, Manfred T1 - Elektromyographische Untersuchungen zur Kräftigung der Oberschenkelmuskulatur mit einem myoelektrischen Stimulator nach arthroskopischen Eingriffen am Kniegelenk JF - Orthopädische Praxis. 43 (2007), H. 10 Y1 - 2007 SN - 0030-588x SP - 539 EP - 542 ER - TY - JOUR A1 - Meyer, Carolin A1 - Gaalen, Kerstin van A1 - Leschinger, Tim A1 - Scheyerer, Max J. A1 - Neiss, Wolfram F. A1 - Staat, Manfred A1 - Müller, Lars P. A1 - Wegmann, Kilian T1 - Kyphoplasty of Osteoporotic Fractured Vertebrae: A Finite Element Analysis about Two Types of Cement JF - BioMed Research International Y1 - 2019 U6 - https://doi.org/10.1155/2019/9232813 SP - Article ID 9232813 ER - TY - JOUR A1 - Stadler, A. M. A1 - Digel, Ilya A1 - Artmann, Gerhard A1 - Embs, Jan P. A1 - Zaccai, Joe A1 - Büldt, Georg T1 - Hemoglobin Dynamics in Red Blood Cells: Correlation to Body Temperature JF - Biophysical Journal. 95 (2008), H. 11 Y1 - 2008 SN - 1542-0086 SP - 5449 EP - 5461 ER - TY - JOUR A1 - Dachwald, Bernd T1 - Optimization of Interplanetary Solar Sailcraft Trajectories Using Evolutionary Neurocontrol JF - Journal of guidance, control, and dynamics. 27 (2004), H. 1 Y1 - 2004 SN - 0162-3192 N1 - 2. ISSN: 0162-3192. - 3. ISSN: 0731-5090 SP - 66 EP - 72 ER - TY - JOUR A1 - Digel, Ilya A1 - Wehlitz, V. A1 - Kayser, Peter A1 - Figiel-Lange, A. A1 - Bassam, R. A1 - Rundstedt, F. von T1 - Suspension depletion approach for exemption of infected Solanum jasminoides cells from pospiviroids JF - Plant Pathology N2 - Despite numerous studies, viroid elimination from infected plants remains a very challenging task. This study introduces for the first time a novel ‘suspension depletion’ approach for exemption of Solanum jasminoides plants from viroids. The proposed method implies initial establishment of suspension cultures of the infected plant cells. The suspended cells were then physically treated (mild thermotherapy, 33 °C), which presumably delayed the replication of the viroid. The viroid concentration in the treated biomass was monitored weekly using pospiviroid-specific PCR. After 10–12 weeks of continuous treatment, a sufficient decrease in viroid concentration was observed such that the infection became undetectable by PCR. The treated single cells then gave rise to microcolonies on a solid culture medium and the obtained viroid-negative clones were further promoted to regenerate into viroid-free plants. Three years of accumulated experimental data suggests feasibility, broad applicability, and good efficacy of the proposed approach. Y1 - 2018 U6 - https://doi.org/10.1111/ppa.12750 SN - 1365-3059 VL - 67 IS - 2 SP - 358 EP - 365 PB - Wiley CY - Oxford ER - TY - JOUR A1 - Dachwald, Bernd A1 - Ohndorf, A. A1 - Gill, E. T1 - Optimization of low-thrust Earth-Moon transfers using evolutionary neurocontrol / Ohndorf, A. ; Dachwald, B. ; Gill, E. JF - IEEE Congress on Evolutionary Computation, 2009. CEC '09. Y1 - 2009 SN - 978-1-4244-2958-5 SP - 358 EP - 364 ER -