Damage localization for beams based on the wavelet correlation operator

The continuous wavelet transform (CWT) is one of the crucial damage identification tools in the vibration-based damage assessment. Because of the vanishing moment property, the CWT method is capable of featuring damage singularity in the higher scales, and separating the global trends and noise progressively. In the classical investigations about this issue, the localization property of the CWT is usually deemed as the most critical point. The abundant information provided by the scale-domain information and the corresponding effectiveness are, however, neglected to some extent. Ultimately, this neglect restricts the sufficient application of the CWT method in damage localization, especially in noisy conditions. In order to address this problem, the wavelet correlation operator is introduced into the CWT damage detection method as a post-processing. By means of the correlations among different scales, the proposed operator suppresses noise, cancels global trends, and intensifies the damage features for various mode shapes. The proposed method is demonstrated numerically with emphasis on characterizing damage in noisy environments, where the wavelet scale Teager-Kaiser energy operator is taken as the benchmark method for comparison. Experimental validations are conducted based on the benchmark data from composite beam specimens measured by a scanning laser vibrometer. Numerical and experimental validations/comparisons present that the introduction of wavelet correlation operator is effective for damage localization in noisy conditions.     

Dynamic responses of K-type and inverted-K-type jacket support structures for offshore wind-turbines

Journal of Central South University - The jacket structure has become more popular as the offshore wind-turbine support structure. K-type and inverted-K-type jacket support structures have superior...     

Theoretical Investigation of the Viscous Damping Coefficient of Hydraulic Actuators

The viscous damping coefficient(VDC) of hydraulic actuators is crucial for system modeling,control and dynamic characteristic analysis.Currently,the researches on hydraulic actuators focus on behavior assessment,promotion of control performance and efficiency.However,the estimation of the VDC is difficult due to a lack of study.Firstly,using two types of hydraulic cylinders,behaviors of the VDC are experimentally examined with velocities and pressure variations.For the tested plunger type hydraulic cylinder,the exponential model B=αυ~(-β),(α0,β0)or B=α_1e~(-β_1υ)+α_2e~(-β_2υ)(α_1,α_20,β_1,β_20),fits the relation between the VDC and velocities for a given pressure of chamber with high precision.The magnitude of the VDC decreases almost linearly under certain velocities when increasing the chamber pressure from 0.6 MPa to 6.0 MPa.Furthermore,the effects of the chamber pressures on the VDC of piston and plunge type hydraulic cylinders are different due to different sealing types.In order to investigate the VDC of a plunger type hydraulic actuator drastically,a steady-state numerical model has been developed to describe the mechanism incorporating tandem seal lubrication,back-up ring related friction behaviors and shear stress of fluid.It is shown that the simulated results of VDC agree with the measured results with a good accuracy.The proposed method provides an instruction to predict the VDC in system modeling and analysis.     

Extended bisection method for parameter identification of the transient heat conduction equation for thermo-elastic deformations during drilling

A new interdisciplinary approach is discribed to identifying unknown parameters using an extended version of the known interval bisection method. This developed method is based on the use of finite elements for calibrating the simulation calculation. The resulting thermo-elastic deformations which occur in drilling processes with impaired cooling lubrication are to be used as correction values for tool positioning in the NC control. Based on the strong impact on workpiece temperature of machining, a simulation approach is presented for calculating the temperature fields and their thermo-elastic consequences. In addition, methods are presented to correct these effects. This paper particularly deals with the temperature fields of drilling operations. Special attention is paid to the technique employed for iterative numerical determination of the unknown heat flux η _w and heat transfer coefficient \(\bar {\gamma }\) values. Finally, the data obtained from experiments are compared with those achieved by numerical simulation in order to verify the efficiency of simulation and determination of parameters.     

„Leben machen,sterben lassen“: Palliative Care und Biomacht

Definition of the problem This article takes a critical look at the current theory and practice of palliative care (PC), how it deals with death and dying, and the underlying guiding principle of a good death. Thereby, Foucault’s concept of biopower is utilized. Argument Because PC aims to facilitate a good death, manifold criteria and measures have been developed that help plan interventions and determine their success. In light of the concept of biopower, certain problematic aspects of this development become manifest that usually remain hidden in the bioethical discourse. Conclusion A goal of PC is to improve the quality of life of the dying and therefore not only treats physical symptoms but also psychological, social, and spiritual suffering; thus, it commits itself to maximizing life in a way that can become overdemanding for the individual and possibly does not satisfy the patient’s real needs.     

Patientenverfügungen und Advance Care Planning bei Demenz und anderen kognitiven Beeinträchtigungen

Definition of the problem

Advance directives for later states of grave cognitive impairment that are typical for late stages of dementia meet with more far-reaching reservations than advance directives for other states of reduced competence. One of the reasons seems to lie in the ethical and psychological conflicts arising from advance directives demanding nontreatment of additional diseases or the abstention from artificial nutrition in situations in which patients show no signs of suffering from their condition.

Arguments

In this article, it is argued that a “mixed” ethical strategy be used for these cases.

Conclusion

Advance directives in the legally defined sense, especially if drawn up in a process of advance care planning, should be followed in order to avoid that advance directives as an instrument of patient autonomy are rendered futile to a degree incompatible with confidence that wishes for terminating medical treatment will be followed. In contrast, the authority of “care directives” without recognized legal status should be restricted to cases in which there is concordance between the patient’s will as expressed in the directive and the patient’s “natural” will in the relevant situation.

     

Mit zweierlei Maß: Die mangelnde Verbindlichkeit von Patientenverfügungen bei untergebrachten Personen mit psychischen Störungen in der Schweiz

Definition of the problem

Full age patients with mental disorders and preserved decision-making capacity are increasingly interested in drafting advance directives. Whereas in Switzerland (as well as in Germany) advance directives are binding in principle, an advance directive is not binding and has only to be considered in case of involuntary admission due to a mental disorder. Thereby, the virtual aim of an advance directive – the anticipated self-determination – is questioned.

Arguments

From an ethical perspective, patients with mental disorders have the same rights as patients with somatic diseases. Therefore, the question arises if there are good reasons for this unequal treatment. In the present contribution, four possible reasons are analyzed: (1) persons with mental disorders are “different”; (2) protection from self-harm; (3) often not present end-of-life context; (4) reduced bindingness as the more appropriate standard in general.

Conclusion

The authors come to the conclusion that patients with mental disorders are often capable of composing a valid advance directive, and just as any other human being, they have a principal and binding right for self-determination, even though they are particularly vulnerable in crisis situations.

     

Patientenverfügung und Behandlungsvereinbarung als Instrumente der Vorausplanung in der forensischen Psychiatrie

Definition of the problem

In Germany as well as in many other countries, mentally ill criminals who are not guilty by reasons of insanity can be sentenced to psychiatric treatment in forensic clinics. In 2011, the German Constitutional Court substantially strengthened these patients’ right to self-determination in case of treatment refusal.

Arguments

In this context, we discuss the significance of instruments of advance healthcare planning. First, we describe the context of psychiatric treatment in forensic clinics and the changes the new German legal regulations brought about. A case study helps to illustrate the consequences of treatment refusal for both patient and healthcare personnel.

Conclusion

Eventually, we discuss if and how advance directives and joint crisis plans can be useful in forensic clinics and how additional measures can help to facilitate patient self-determination.

     

First-Principles Study of the High-Temperature Behaviors of the Willemite-Ⅱ and Post-Phenacite Phases of Silicon Nitride

The structural and elastic properties of the recently-discovered wⅡ- and δ-Si_3N_4 are investigated through the plane-wave pseudo-potential method within ultrasoft pseudopotentials.The elastic constants show that wⅡ- and δ-Si_3N_4 are mechanically stable in the pressure ranges of 0-50 GPa and 40-50 GPa,respectively.The α→wⅡ phase transition can be observed at 18.6 GPa and 300 K.The β→δ phase transformation occurs at pressures of 29.6,32.1,35.9,39.6,41.8,and 44.1 GPa when the temperatures are100,200,300,400,500,and 600 K,respectively.The results show that the interactions among the N-2s,Si-3s,3p bands(lower valence band) and the Si-3p,N-2p bands(upper valence band) play an important role in the stabilities of the wⅡ and S phases.Moreover,several thermodynamic parameters(thermal expansion,free energy,bulk modulus and heat capacity) of δ-Si_3N_4 are also obtained.Some interesting features are found in these properties.δ-Si_3N_4 is predicted to be a negative thermal expansion material.The adiabatic bulk modulus decreases with applied pressure,but a majority of materials show the opposite trend.Further experimental investigations with higher precisions may be required to determine the fundamental properties of wⅡ- andδ-Si_3N_4.     

Effect of wafer size on the film internal stress measurement by wafer curvature method

Wafer curvature method has been applied to determine the internal stress in the films using Stoney’s equation. During the film deposition, the wafer fixation on the sample holder will restrict the deformation of the rectangle-shaped wafer, which may result in the stress datum difference along length and width direction. In this paper, the effect of wafer size and the wafer fixation on the TiN film internal stress measured by wafer curvature method was discussed. The rectangle-shaped wafers with different length/width ratios (L/W=1:1, 2:1, 3:1 and 4:1) were fixed as a cantilever beam. After the TiN films deposition, the profiles of the film/wafer were measured using a stylus profilometer and then the internal stress was calculated using the Stoney equation in the film. The results showed that the fixed end of the wafers limited to some degree the curvature of the wafers along the width direction. For film internal stress measured by wafer curvature method, the wafer profile should be scanned along the length direction and the scan distance should be greater than or equal to half of wafer length. When the length/width ratio of the wafer reached 3:1, the wafer curvature and the calculated stress were basically the same at different positions along the length direction. For film internal stress measured by wafer curvature method, it was recommended that the length/width ratio of wafer should be considered to be greater than or equal to 3:1, and the deformed profile was scanned along the length direction.