Exact finite beam element for open thin walled doubly symmetric members under torsional and warping moments

Starting with total potential energy variational principle, the governing equilibrium coupled equations for the torsional-warping static analysis of open thin-walled beams under various torsional and warping moments are derived. The formulation captures shear deformation effects due to warping. The exact closed form solutions for torsional rotation and warping deformation functions are then developed for the coupled system of two equations. The exact solutions are subsequently used to develop a family of shape functions which exactly satisfy the homogeneous form of the governing coupled equations. A super-convergent finite beam element is then formulated based on the exact shape functions. Key features of the beam element developed include its ability to (a) eliminate spatial discretization arising in commonly used finite elements, and (e) eliminate the need for time discretization. The results based on the present finite element solution are found to be in excellent agreement with those based on exact solution and ABAQUS finite beam element solution at a small fraction of the computational and modelling cost involved.

Nonlinearly Preconditioned FETI Solver for Substructured Formulations of Nonlinear Problems

We consider the finite element approximation of the solution to elliptic partial differential equations such as the ones encountered in (quasi)-static mechanics, in transient mechanics with implicit time integration, or in thermal diffusion. We propose a new nonlinear version of preconditioning, dedicated to nonlinear substructured and condensed formulations with dual approach, i.e., nonlinear analogues to the Finite Element Tearing and Interconnecting (FETI) solver. By increasing the importance of local nonlinear operations, this new technique reduces communications between processors throughout the parallel solving process. Moreover, the tangent systems produced at each step still have the exact shape of classically preconditioned linear FETI problems, which makes the tractability of the implementation barely modified. The efficiency of this new preconditioner is illustrated on two academic test cases, namely a water diffusion problem and a nonlinear thermal behavior.

Iranisches Personennamenbuch Band V/Faszikel 3: Iranische Namen in Nebenüberlieferungen Indogermanischer Sprachen

The Iranian element is the largest layer of the Armenian borrowed lexicon. It comprises a period of more than 2.500 years starting from pre-Achaemenid times up to the modern period. Also the number of Armenian personal names of Iranian origin is quite large, roughly estimated one quarter of all Armenian personal names. The Armenian evidence is of vital importance for completing the Iranian onomasticon. In many cases, Middle Persian and Parthian namesakes of Armenian personal names are not directly attested. Besides, Armenian helps to determine the exact shape of Iranian names. The present fascicle of the "Iranisches Personennamenbuch" aims to collect and etymologically interpret all the Iranian personal names, which are attested in Armenian texts up to 1300 CE. Occasionally, it also comprises names that are attested at a later stage but are likely to belong to earlier periods, as well as younger forms that are related with older names and are therefore relevant for the philological or etymological discussion of the latter. The volume comprises 872 entries and includes (1) names of Iranian people of various kinds (kings, queens, princes, generals, etc.) that occur in Armenian texts, and (2) names of Iranian origin that were/are borne by Armenian people. It includes a huge range of new etymologies or corrected versions of pre-existing etymologies, as well as new names and corrected forms of names discovered in critical texts and voluminous corpora of inscriptions and colophons of Armenian manuscripts that have not been available for earlier researchers of the Armenian onomastics.

A Vibration Sensor-Based Method for Generating the Precise Rotor Orbit Shape with General Notch Filter Method for New Rotor Seal Design Testing and Diagnostics

Verification of the behaviour of new designs of rotor seals is a crucial phase necessary for their use in rotary machines. Therefore, experimental equipment for the verification of properties that have an effect on rotor dynamics is being developed in the test laboratories of the manufacturers of these components all over the world. In order to be able to compare the analytically derived and experimentally identified values of the seal parameters, specific requirements for the rotor vibration pattern during experiments are usually set. The rotor vibration signal must contain the specified dominant components, while the others, usually caused by unbalance, must be attenuated. Technological advances have made it possible to use magnetic bearings in test equipment to support the rotor and as a rotor vibration exciter. Active magnetic bearings allow control of the vibrations of the rotor and generate the desired shape of the rotor orbit. This article presents a solution developed for a real test rig equipped with active magnetic bearings and rotor vibration sensors, which is to be used for testing a new design of rotor seals. Generating the exact shape of the orbit is challenging. The exact shape of the rotor orbit is necessary to compare the experimentally and numerically identified properties of the seal. The generalized notch filter method is used to compensate for the undesired harmonic vibrations. In addition, a novel modified generalized notch filter is introduced, which is used for harmonic vibration generation. The excitation of harmonic vibration of the rotor in an AMB system is generally done by injecting the harmonic current into the control loop of each AMB axis. The motion of the rotor in the AMB axis is coupled, therefore adjustment of the amplitudes and phases of the injected signals may be tedious. The novel general notch filter algorithm achieves the desired harmonic vibration of the rotor automatically. At first, the general notch filter algorithm is simulated and the functionality is confirmed. Finally, an experimental test device with an active magnetic bearing is used for verification of the algorithm. The measured data are presented to demonstrate that this approach can be used for precise rotor orbit shape generation by active magnetic bearings.

Interest Rates and Macroeconomic Investment under Uncertainty

The interest rate is generally considered as an important driver of macroeconomic investment characterised by a particular form of path dependency, “hysteresis”. At the same time, the interest rate channel is a central ingredient of monetary policy transmission. In this context, we shed light on the issue (which currently is a matter of concern for many central banks) whether uncertainty over future interest rates at the zero lower bound hampers monetary policy transmission. As an innovation we derive the exact shape of the “hysteretic” impact of rate changes on macroeconomic investment under different sorts of uncertainty. Starting with hysteresis effects on the micro level, we apply an adequate aggregation procedure to derive the interest rate effects on a macro level. Our results may serve as a guideline for future central banks’ policies on how to stimulate investment in times of low or even zero interest rates and uncertainty.

Designer Cranioplasty at Budget Prices: A Novel Use of 3D Printing Technology

Background Cranioplasty using synthetic materials for restoration of the exact shape of the skull has always remained a challenge until the development of 3D printing technology. However, the high-cost of available 3D printed implants limits their extensive use. Objectives To study the effectiveness of a low-cost, 3D-printed template for molding the polymethyl methacrylate (PMMA) (bone cement) in order to achieve exact contours of the skull specific to each patient. Materials and Methods 10 cranioplasties have been performed between July 2018 to December 2019 in a variety of craniotomy defects using bone cement flaps shaped using custom-made molds. The mold was 3D-printed and based on each patient’s CT images in digital imaging and communications in medicine (DICOM). Miniplates and screws were used to fix the flap. Postoperatively, clinical and radiological evaluation were done to assess patient satisfaction and accuracy of contour achieved. Results Patient satisfaction as well as accuracy of contouring, as seen on postoperative CT scans, were excellent. There were no notable complications on follow-up. Conclusion PMMA cranioplasty flap, contoured using a 3D-printed mold, is a very cost-effective alternative for restoration of skull contour for various craniotomy defects.Polymethyl methacrylate (PMMA) molded to form the exact shape of lost calvarium using 3D printed plastic templates is a smart and economical solution

3D Printing Technologies in Metallic Implants: A Thematic Review on the Techniques and Procedures

Additive manufacturing (AM) is among the most attractive methods to produce implants, the processes are very swift and it can be precisely controlled to meet patient’s requirement since they can be produced in exact shape, dimension, and even texture of different living tissues. Until now, lots of methods have emerged and used in this field with diverse characteristics. This review aims to comprehensively discuss 3D printing (3DP) technologies to manufacture metallic implants, especially on techniques and procedures. Various technologies based on their main properties are categorized, the effecting parameters are introduced, andthe history of AM technology is briefly analyzed. Subsequently, the utilization of these AM-manufactured components in medicine along with their effectual variables is discussed, and special attention is paid on to the production of porous scaffolds, taking pore size, density, etc., into consideration. Finally, 3DP of the popular metallic systems in medical applications such as titanium, Ti6Al4V, cobalt-chromium alloys, and shape memory alloys are studied. In general, AM manufactured implants need to comply with important requirements such as biocompatibility, suitable mechanical properties (strength and elastic modulus), surface conditions, custom-built designs, fast production, etc. This review aims to introduce the AM technologies in implant applications and find new ways to design more sophisticated methods and compatible implants that mimic the desired tissue functions.

Parametric design analysis of elliptical shroud profile

<abstract> <p>Parametric design analysis for Eccentric Rotated Ellipsoid (ERE) shroud profile is conducted whereas the design model is validated experimentally. A relation between shroud inlet, length and exit diameter is established, different ratios related to the wind turbine diameter are introduced, and solution for different ERE family curves that passes on the inlet, throat, and exit points is studied. The performance of the ERE shroud is studied under different wind velocities ranging from 5–10 m/s.</p> <p>The method used in creating the shroud profile is by solving the ERE curve equations to generate large family of solutions. The system is modeled as axisymmetric system utilizing commercial software package. The effect of the parameters; shroud length, exit diameter, inlet diameter, turbine position with respect to the shroud throat, and wind velocity are studied. An optimum case for each shroud length, exit diameter and location of the shroud with respect to the wind turbine throat axis are achieved.</p> <p>The simulation results show an increase in the average wind velocity by 1.63 times of the inlet velocity. This leads to a great improvement in the wind turbine output power by 4.3 times of bare turbine. One of the achieved optimum solutions for the shroud curves has been prototyped for experimental validation. The prototype has been manufactured using 3D printing technology which provides high accuracy in building the exact shape of shroud design curve. The results show very good agreement with the experimental results.</p></abstract>

The Regulation of Biobanking in Germany

Biobanking in Germany is currently not subject to sui generis regulation. Instead, a plethora of norms from differing areas of law form the bundle of regulation that applies to biobanking. The exact shape and extent of the bundle depends on the exact configuration of the biobank. In the context of data protection, the rather fragmented nature of the regulation is to a certain extent alleviated by the direct impact of the EU General Data Protection Regulation (GDPR). In particular, the federalized system of data protection in Germany is simplified by an overarching set of norms that apply equally across the board. Whilst this is a welcome systematization of this part of the regulation of biobanking in Germany, the exact nature of the implementation of the Regulation raises novel issues in its own right. In this paper, I will outline the fragmented nature of biobank regulation in Germany, illustrate the issues on the basis of Germany’s population biobank NaKo and then discuss some of the more significant issues raised by the GDPR in the context of biobanking.