498 Works

Dynamic simulation of different transport options of renewable hydrogen to a refinery in a coupled energy system approach

Lisa Andresen, Carsten Bode & Gerhard Schmitz
Three alternative transport options for hydrogen generated from excess renewable power to a refinery of different scales are compared to the reference case by means of hydrogen production cost, overall efficiency, and CO2 emissions. The hydrogen is transported by a) the natural gas grid and reclaimed by the existing steam reformer, b) an own pipeline and c) hydrogen trailers. The analysis is applied to the city of Hamburg, Germany, for two scenarios of installed renewable...

Draft genome sequence of type strain Clostridium pasteurianum DSM 525 (ATCC 6013) : a promising producer of chemicals and fuels

Sugima Rappert, Lifu Song, Wael Sabra, Wei Wang & An-Ping Zeng
Clostridium pasteurianum, an anaerobic bacterium able to utilize atmospheric free nitrogen for biosynthesis, has recently been proven to be a promising producer of chemicals and fuels, such as 1,3-propanediol and n-butanol. Here, we report the high-quality draft genome sequence of DSM 525, a type strain of C. pasteurianum.

Integration of oxygen-containing exhaust gas into the air separation unit of an oxyfuel power plant

Jens Dickmeis & Alfons Kather
The Oxyfuel process is one possible solution to lower the high specific CO2 emissions of coal-fired power plants. The flue gas generated by this process has a high CO2 content, due to the missing nitrogen. However the dried flue gas still contains approximately 15 vol% (dry) impurities (NOx, SOx, O2, N2 and Ar). To further increase the CO2 purity the flue gas needs to be treated in a gas processing unit (GPU). Additional downstream gas...

Development of plasma-laser-hybrid welding process

Claus Emmelmann, Marc Kirchhoff & Nikolai Petri
In order to fulfill demands for quality and efficiency in the field of welding engineering, numerous works in research on the optimization of the welding processes are in progress. [1] Aims of this research are increasing the welding speed, stabilizing the welding processes, decreasing the reject rate and reducing the pre and post welding machining. This work relates to the development of a new plasma-laser hybrid welding method in order to increase the productivity of...

Process and mechanical properties: Applicability of a scandium modified Al-alloy for laser additive manufacturing

Katja Schmidtke, Frank Palm, A. Hawkins & Claus Emmelmann
The applicability of an aluminium alloy containing scandium for laser additive manufacturing (LAM) is considered. Modified aluminium alloys with a scandium content beyond the eutectic point offer great potential to become a high prioritized aerospace material. Depending on other alloying elements like magnesium or zirconium, strongly required weight reduction, corrosion resistance and improved strength properties of metallic light weight alloys can be achieved. The development, production and testing of parts built up by a laser...

Evaluation of fixed-bed cultures with immobilized Lactococcus Lactis ssp. Lactis on different scales

Rebecca Faschian, Ilyas Eren, Steven Minden & Ralf Pörtner
Fixed-bed processes, where cells are immobilized within macroporous carriers, are a promising alternative to processes with suspended cells. A scale-up concept is presented in order to evaluate the performance as part of process design of fixed-bed processes. Therefore, Lactococcus lactis cultivation in chemostat and batch mode was compared to fixed bed cultures on three different scales, the smallest being the downscaled Multiferm with 10 mL fixed bed units, the second a 100 mL fixed-bed reactor...

Analysis of wind turbine using QBlade software

Mustafa Alaskari, Oday Ibraheem Abdullah & Mahir H. Majeed
Owing to the fast development in the energy field, the demands are increasing to improve energy efficiency and lifetime of wind turbine. The wind blades are considered as the most important and expensive part in the wind system. Therefore, it's important to understand deeply the behaviour of turbine blades. In this research paper, full details were presented to analyze and optimize the behaviour and performance of the blade of the small horizontal axis wind turbine...

Vibro-acoustic and nonlinear analysis of cadavric femoral bone impaction in cavity preparations

Sebastian Oberst, Johanna Bätz, Graeme Michael Campbell, Frank Lampe, Joseph C. S. Lai, Norbert Hoffmann & Michael Morlock
Owing to an ageing population, the impact of unhealthy lifestyle, or simply congenital or gender specific issues (dysplasia), degenerative bone and joint disease (osteoarthritis) at the hip pose an increasing problem in many countries. Osteoarthritis is painful and causes mobility restrictions; amelioration is often only achieved by replacing the complete hip joint in a total hip arthroplasty (THA). Despite significant orthopaedic progress related to THA, the success of the surgical process relies heavily on the...

Comparison of three methods of length compensation in a parallel kinematic and their equivalence conditions

Shucen Du, Josef Schlattmann, Stefan Schulz & Arthur Seibel
This paper is a further development of a previous work (PAMM 16, 51-52). In this paper, we derive an analytical formulation of the linear actuators' length variations for a 2-1-2 DOF joint designed parallel hexapod based on Riebe and Ulbrich's method (Arch. Appl. Mech. 72, 817-829) and the Euler angles based matrix method. The equivalence conditions as well as the computation errors are given and compared with a quaternion based method.

Autonomous vehicles and autonomous driving in freight transport

Heike Flämig
The degree of vehicle automation is continuously rising in all modes of transport both on public traffic infrastructure and in-house transport within company grounds, in order to improve the productivity, reliability, and flexibility of transport.

Typical pitfalls of simulation modeling : lessons learned from armed forces and business

Rolf Barth, Matthias Meyer & Jan Spitzner
This paper identifies possible pitfalls of simulation modeling and suggests ways to prevent them. First, we specify five typical pitfalls that are associated with the process of applying simulation models and characterize the "logic of failure" (Dörner 1996) behind the pitfalls. Then, we illustrate important aspects of these pitfalls using examples from applying simulation modeling to military and managerial decision making and present possible solutions to them. Finally, we discuss how our suggestions for avoiding...

Time-temperature-plasticization superposition principle : predicting creep of a plasticized epoxy

Andrey E. Krauklis, Anton G. Akulichev, Abedin I. Gagani & Andreas T. Echtermeyer
Long-term creep properties and the effect of water are important for fiber reinforced polymer (FRP) composite materials used in offshore applications. Epoxies are often used as a matrix material in such composites. A typical design lifetime of offshore FRP structures is 25 or more years in direct contact with water leading to some deterioration of the material properties. Knowing and predicting the extent of the material property deterioration in water is of great interest for...

On the process-related rivet microstructural evolution, material flow and mechanical properties of Ti-6Al-4V/GFRP friction-riveted joints

Natascha Zocoller Borba, Conrado R. M. Afonso, Lucian A. Blaga, Jorge F. dos Santos, Leonardo Bresciani Canto & Sergio Amancio
In the current work, process-related thermo-mechanical changes in the rivet microstructure, joint local and global mechanical properties, and their correlation with the rivet plastic deformation regime were investigated for Ti-6Al-4V (rivet) and glass-fiber-reinforced polyester (GF-P) friction-riveted joints of a single polymeric base plate. Joints displaying similar quasi-static mechanical performance to conventional bolted joints were selected for detailed characterization. The mechanical performance was assessed on lap shear specimens, whereby the friction-riveted joints were connected with AA2198...

Label-free photonic biosensors fabricated with low-loss hydrogenated amorphous silicon resonators

Timo Lipka, Lennart Wahn, Hoc Khiem Trieu, Lutz Hilterhaus & Jörg Müller
The precise detection of chemicals and biomolecules is of great interest in the areas of biotechnology and medical diagnostics. Thus, there is a need for highly sensitive, small area, andlow-cost sensors. We fabricated and optically characterized hydrogenated amorphous silicon photonic resonators for label-free lab-on-chip biosensors. The sensing was performed with small-footprint microdisk and microring resonators that detect a refractive-index change via the evanescent electric field. Homogeneous sensing with NaCl and surface-sensing experiments with immobilized bovine...

3D Reciprocal Space Mapping of a Columnar Discotic Liquid Crystal Confined in Nanopores

Patrick Huber
Videos, die das 3-D Kartieren des Reziproken Raums mit Hilfe von synchrotronbasierter Röntgendiffraktion illustrieren. Electronic Support Information des Artikels K. Sentker at al. "Self-Assembly of Liquid Crystals in Nanoporous Solids for Adaptive Photonic Metamaterials" Nanoscale DOI:10.1039/C9NR07143A (2019)

Energetic evaluation of different flow sheet modifications of post-combustion CO₂ capture plant at coal and natural gas fired power plant for a generic improved solvent

Sören Ehlers, Volker Roeder, Alfons Kather, Prachi Singh & John Davison
The post-combustion capture (PCC) technology is a promising possibility to reduce CO₂ emissions of fossil fuel fired power plants. One of the main concerns for the PCC is the loss in electric power output. A reduction in efficiency penalty for solvent based PCC can be achieved by improving the solvent properties as well as by improving the process design. There are many different process flow sheet modifications with an improvement in process design reported in...

Directional soliton and breather beams

Amin Chabchoub, Kento Mozumi, Norbert Hoffmann, Alexander V. Babanin, Alessandro Toffoli, James N. Steer, Ton S. van den Bremer, Nail N. Akhmediev, Miguel Onorato & Takuji Waseda
Solitons and breathers are nonlinear modes that exist in a wide range of physical systems. They are fundamental solutions of a number of nonlinear wave evolution equations, including the unidirectional nonlinear Schrödinger equation (NLSE). We report the observation of slanted solitons and breathers propagating at an angle with respect to the direction of propagation of the wave field. As the coherence is diagonal, the scale in the crest direction becomes finite; consequently, beam dynamics form....

PV-betriebene Umkehrosmoseanlage zur Meerwasserentsalzung – Modellierung und Analyse verschiedener Energieversorgungsvarianten

Anas Sanna, Martin Kaltschmitt & Mathias Ernst
Die Umkehrosmose ist eine sehr energieeffiziente Option zur Meerwasserentsalzung. Da sie nur elektrische Energie nachfragt, bietet sich aus Klimaschutzgru¨nden eine Kombination von Umkehrosmose- und Photovoltaik(PV)-Anlagen an. Deshalb wird hier eine PV-basierte Umkehrosmose-Anlage zur Meerwasserentsalzung fu¨r einen Standort in Saudi-Arabien ausgelegt und modelliert. Ausgehend davon werden verschiedene Varianten einer PV-versorgten Meerwasserentsalzungsanlage untersucht und daraus Schlussfolgerungen fu¨r den Bau derartiger Anlagen abgeleitet.

Looking for a needle in a haystack : how to search for bottom‐up social innovations that solve complex humanitarian problems

Daniel Johannes Kruse, Moritz Göldner, Katrin Eling & Cornelius Herstatt
The worldwide increase in societal challenges is putting pressure on humanitarian organizations to develop sophisticated approaches to leverage social innovations in the humanitarian sector. Since humanitarian problems are complex problems, with the relevant knowledge being hidden, organizational search theory advocates the application of bottom‐up and theory‐guided search processes to identify the social innovations that solve these. Unfortunately, there has been no theoretical attention to understanding which approaches apply in this context. Further, established theory‐guided bottom‐up...

Predicting industrial-scale cell culture seed trains – a bayesian framework for model fitting and parameter estimation, dealing with uncertainty in measurements and model parameters, applied to a nonlinear kinetic cell culture model, using an MCMC method

Tanja Hernández Rodríguez, Christoph Posch, Julia Schmutzhard, Josef Stettner, Claus Weihs, Ralf Pörtner & Björn Frahm
Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. For production of biopharmaceuticals in suspension cell culture, seed trains are required to increase cell number from cell thawing up to production scale. Because cultivation conditions during the seed train have a significant impact on cell performance in production scale, seed train design, monitoring, and development of optimization strategies is important. This can be facilitated by model-assisted prediction methods, whereby the performance depends on the prediction accuracy,...

Hybrid instrumentation in lumbar spinal fusion : a biomechanical evaluation of three different Instrumentation techniques

Peter Obid, Reza Danyali, Rebecca Kueny, Gerd Huber, Michael Reichl, Alexander Richter, Thomas Niemeyer, Michael Morlock, Klaus Püschel & Hüseyin Übeyli
Study Design Ex vivo human cadaveric study. Objective The development or progression of adjacent segment disease (ASD) after spine stabilization and fusion is a major problem in spine surgery. Apart from optimal balancing of the sagittal profile, dynamic instrumentation is often suggested to prevent or impede ASD. Hybrid instrumentation is used to gain stabilization while allowing motion to avoid hypermobility in the adjacent segment. In this biomechanical study, the effects of two different hybrid instrumentations...

3D printed nozzles on a silicon fluidic chip

Sven Bohne, Michael Heymann, Henry N. Chapman, Hoc Khiem Trieu & Saša Bajt
Serial femtosecond crystallography is a new method for protein structure determination utilizing intense and destructive X-ray pulses generated by free-electron lasers. The approach requires the means to deliver hydrated protein crystals to a focused X-ray beam and replenish them at the repetition rate of the pulses. A liquid-jet sample delivery system where a gas dynamic virtual nozzle is printed directly on a silicon-glass microfluidic chip using a 2-photon-polymerization 3D printing process is implemented. This allows...

Extraction of oil and minor compounds from oil palm fruit with supercritical carbon dioxide

Phan-Tai Huan & Gerd Brunner
A significant quantity of tocochromanols and carotenoids remains in the residual from palm oil production by traditional screw pressing. Supercritical carbon dioxide extraction was used as alternative method with the purpose to recover better these valuable minor compounds. Total oil yield and co-extracted water were investigated in the course of extraction. Tocochromanols and carotenoids were evaluated, not only in the extraction oil, but also in the oil of residual fibre. Modelling of extraction process was...

Adsorption–strain coupling at solid surfaces

Jörg Weissmüller
This brief review inspects how chemistry or electrochemistry at a solid–vapor or solid–electrolyte interface couple to the mechanics of the solid. Emphasis is on the complementarity of two at first sight unrelated phenomena: on the one hand, adsorption or electric charging change the local tangential stresses in the solid surface; on the other hand, a tangential strain of the surface changes the adsorption enthalpy and the chemical or electric potential. One and the same materials...

Porous starch materials via supercritical- and freeze-drying

Victor Baudron, Pavel Gurikov, Irina Smirnova & Steve Whitehouse
The production of porous materials based on starch has been explored with supercritical drying - yielding aerogel - and freeze-drying. The two drying procedures were applied on the same gelling solution of amylomaize starch pasted at 140 °C and for two concentrations (5 and 10 wt.%). After gelation and retrogradation, water from the samples to be supercritically dried was exchanged to ethanol. The resulting starch aerogel presented high specific surface area (197 m2/g). Freeze-drying was...

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  • 2019
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