bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance Characteristics of the Magnetic Constrained Layer Damping
Authors: Baz A. , Poh S. 
Published: January 2014

A new class of surface damping treatment is proposed to provide effective means for attenuating undesirable structural vibrations. The proposed treatment relies in its operation on the use of smart damping treatments which consist of integrated arrays of constrained visco‐elastic damping layers that are controlled passively by a specially arranged network of permanent magnets. The interaction between the magnets and the visco‐elastic layers aims at enhancing the energy dissipation characteristics of the damping treatments. In this manner, it would be possible to manufacture structures that are light in weight which are also capable of meeting strict constraints on structural vibration when subjected to unavoidable disturbances.Emphasis is placed here on introducing the concept and the basic performance characteristics of this new class of smart Magnetic Constrained Layer Damping (MCLD) treatments. Comparisons are also presented with conventional Passive Constrained Layer Damping (PCLD) in order to determine the merits and limitation of the MCLD treatments.
Topographic Mapping of P300 and Frontal Cognitive Function in Parkinson’s Disease
Authors: Iijima Mutsumi , Osawa Mikio , Iwata Makoto , Miyazaki Akiko , Tei Hideaki 
Published: January 2014

The purpose of this study was to evaluate the relationship between P300 that is one of the event‐related potentials and frontal cognitive functions in Parkinson’s disease (PD) without clinically apparent dementia.Subjects were 20 PD cases 48 to 79 years of age, all of whom were within normal limits on the Mini‐Mental State examination, and 55 age‐matched healthy adults.P300 was elicited with an auditory oddball paradigm and recorded at 15 sites on the scalp. Cognitive functioning of the frontal lobe was evaluated using the New Modified Wisconsin Card Sorting Test (WCST) and the Letter Pick‐Out Test (LPOT) which reflects selective attention and semantic categorization.P300 latency was delayed in 30.0% of P300 demonstrated abnormal distribution in 20.0%. the WCST and the LPOT were abnormal in 15.0%, P300 latency significantly correlated with number of subcategories achieved on the WCST. P300 amplitude correlated with scores on the LPOT. These results suggest that cognitive dysfunction which linked partly to the frontal lobe might begin in PD even without clinically apparent dementia.
An Experimental Technique for Structural Diagnostic Based on Laser Vibrometry and Neural Networks
Authors: Castellini Paolo , Revel Gian Marco 
Published: January 2014

In recent years damage detection techniques based on vibration data have been largely investigated with promising results for many applications. In particular, several attempts have been made to determine which kind of data should be extracted for damage monitoring.In this work Scanning Laser Doppler Vibrometry (SLDV) has been used to detect, localise and characterise defects in mechanical structures. After dedicated post‐processing, a neural network has been employed to classify LDV data with the aim of automating the detection procedure.In order to demonstrate the feasibility and applicability of the proposed technique, a simple case study (an aluminium plate) has been approached using both Finite Element simulations and experimental investigations. The proposed methodology was then applied for the detection of damages on real cases, as composite material panels. In addition, the versatility of the approach was demonstrated by analysing a Byzantine icon, which can be considered as a singular kind of composite structure.The presented methodology has proved to be efficient to automatically recognise defects and also to determine their depth in composite materials. Furthermore, it is worth noting that the diagnostic procedure supplied correct results for the three investigated cases using the same neural network, which was trained with the samples generated by the Finite Element model of the aluminium plate. This represents an important result in order to simplify and shorten the procedure for the training set preparation, which often constitutes the main problem for the application of neural networks on real cases or in industrial environments.
SPECT in Focal Epilepsies
Authors: Duncan Roderick 
Published: January 2014

Brain perfusion changes during seizures were first observed in the 1930s. Single Photon Emission Computed Tomography (SPECT) was developed in the 1970s, and tracers suitable for the imaging of regional cerebral perfusion (rCP) became available in the 1980s. The method was first used to study rCP in the interictal phase, and this showed areas of low perfusion in a proportion of cases, mainly in patients with temporal lobe epilepsies. However, the trapping paradigm of tracers such as hexamethyl propyleneamine oxime (HMPAO) provided a practicable method of studying changes in rCP during seizures, and a literature was established in the late 1980s and early 1990s showing a typical sequence of changes during and after seizures of mesial temporal lobe origin; the ictal phase was associated with large increases in perfusion throughout the temporal lobe, with first the lateral, then the mesial temporal lobe becoming hypoperfused in the postictal phase. Activation and inhibition of other structures, such as the basal ganglia and frontal cortex, were also seen. Studies of seizures originating elsewhere in the brain have shown a variety of patterns of change, according to the structures involved. These changes have been used practically to aid the process of localisation of the epileptogenic zone so that epilepsy surgery can be planned.Some neuroreceptors (e.g. benzodiazepine receptors) can be studied using SPECT, and have shown localised abnormalities. SPECT has also been used to study brain function during the intracarotid amytal test. SPECT images of all kinds can be analysed using numerical techniques such as statistical parametric mapping, and such techniques promise to improve the yield of information from ictal studies.
Review: Modeling Damping in Mechanical Engineering Structures
Authors: Lalanne Michel 
Published: January 2014

This paper is concerned with the introduction of damping effects in the analysis of mechanical engineering structures. Damping can be considered as being generated by concentrated elements, by distributed elements, or by several effects existing simultaneously. Modeling damping for different engineering situations is described and some applications are presented briefly.Erratum to “Review: Modeling Damping in Mechanical Engineering Structures”dx.doi.org/10.1155/2000/481496
Vibration Control of Linear Split Stirling Cryogenic Cooler for Airborne Infrared Application
Authors: Veprik A.M. , Babitsky V.I. , Pundak N. , Riabzev S.V. 
Published: January 2014

Modern infrared imagers often rely on the split Stirling cryogenic coolers the linear compressors of which are the well‐known sources of harmonic disturbance. The traditional method of their passive isolation fails to meet the restraints on the static and dynamic deflections which are originated by the combined action of the airborne g‐loading and harsh random vibration.The vibration protection system, which combines a stiff and heavily damped vibration isolator with tuned dynamic absorber, is studied and optimised for use in the design of an airborne infrared device.Such a design is aimed, primarily, at essential dynamic suppression of the harmonic force which is produced by the linear compressor and, secondarily, at minimisation of environmental vibration loads transmitted through the infrared device to the linear compressor. Experimental testing backed up the theoretical results.
The Requirement for Hydrostatic Initialisation in LS‐DYNA/USA Finite Element Models
Authors: Hammond Lloyd , Grzebieta Raphael 
Published: January 2014

The LS‐DYNA/USA (Underwater Shock Analysis) coupled finite element codes are being investigated as a tool for predicting the local response of compliant plate structures subjected to far‐field underwater explosion.It had previously been observed in LS‐DYNA/USA models that extraneous pressure build‐ups emanating from the DAA (doubly asymptotic approximation) boundaries may occur in the surrounding fluid region of the model, which inevitably lead to erroneous modelling of fluid‐structure interaction and inaccurate structural responses. These instabilities typically result in divergence of the solution and eventually premature termination of the simulation. After a comprehensive investigation, it was found that the instabilities did not arise if the finite element model was hydrostatically initialised before conducting the LS‐DYNA/USA simulation.The purpose of this study is to investigate the need for achieving hydrostatic equilibrium prior to the modelling of the shock wave propagation through the fluid‐structure media. The method for achieving static equilibrium with the current version of the LS‐DYNA/USA software is presented. The example simulations presented show that the hydrostatic initialisation procedure is effective in removing instabilities occurring at the DAA‐fluid boundary, associated with the USA ambient hydrostatic pressure condition.
Energy Dissipation from Vibrating Floor Slabs due to Human‐Structure Interaction
Authors: Brownjohn James M.W. 
Published: January 2014

Lightweight pre‐cast flooring systems using post‐tensioning to increase strength but not stiffness are increasingly popular, and vibration serviceability problems tend to govern design of such floors where human occupants are increasingly concerned with vibrations. At the same time as inducing response, stationary human observers can also participate in the response as mitigating influence and it is clear that a human behaves as a highly effective damper, even when seated.Experiments were done to study energy flow and storage in a 1.2 tonne vibrating concrete plank with a human occupant. Results showed that damping could increase to as much as 10% frequency shifts (usually decreases) in the slab apparent resonant frequency, depending on occupant posture. Simple lumped mass mathematical models were also used to study the vibrating human‐structure system through dynamic simulations, corroborating the findings.Further corroboration was provided from measurements on a prototype full‐scale floor slab occupied by several hundred people who were either jumping or sitting. Modal analysis of vibration response signals showed that normal floor resonance associated with jumping at a sub‐harmonic of the floor natural frequency was almost completely damped out by the passive (seated) people.
Combining Response Surface Optimization and Stochastic Analysis for Crashworthiness Design – an Introductory Study
Authors: Fredriksson Lars A. , Schramm Uwe 
Published: January 2014

Objective of the design process are cost effective designs that meet certain expectations with respect to functionality and appearance. Designs are created in an iterative process where analyses of the structural behavior lead to changes in the design. The use of optimization technology makes design changes to be driven directly by analysis results. The application of optimization allows an efficient search for the right combination of design variables for a certain design. Additional use of stochastic methods in order to analyze the design from a statistical standpoint adds robustness to the design and prevents unpleasant surprises in later physical testing.This paper discusses methodology to optimize structures that undergo impact loading. Objective and constraints are transient dynamic responses. The optimization problem is solved using a sequential response surface method. An explicit finite element code is used to solve the transient dynamic problem. The optimization is not performed on results from single simulations but on statistical results from a stochastic analysis. The stochastic analysis is driven using a Monte Carlo method. Commercial software is used for the implementation of the methodology.The results from the study indicate that a combination of optimization and stochastic analysis can add safety margins to a design with respect to robustness against physical errors in the design itself and against changes in load levels and load cases. However, this initial study must be followed up by more in‐depth investigations to fully understand the benefits of combined optimization‐stochastic analysis.
Vibration Protection of Sensitive Components of Infrared Equipment in Harsh Environments
Authors: Veprik A.M. , Babitsky V.I. , Pundak N. , Riabzev S.V. 
Published: January 2014

This article addresses the principles of optimal vibration protection of the internal sensitive components of infrared equipment from harsh environmental vibration. The authors have developed an approach to the design of external vibration isolators with properties to minimise the vibration‐induced line‐of‐sight jitter which is caused by the relative deflection of the infrared sensor and the optic system, subject to strict constraints on the allowable sway space of the entire electro‐optic package. In this approach, the package itself is used as the first‐level vibration isolation stage relative to the internal highly responsive components.It was predicted analytically, and confirmed experimentally, that the proposed vibration isolation system would be capable of a sixfold reduction of the dynamic response of the infrared sensor as compared to the case of rigid mounting of the entire package.
The Introduction of Spin to an Existing Flexible Shot Model within a Gun Dynamics Simulation
Authors: Bulman David N. 
Published: January 2014

The paper describes the enhancement of an existing gun dynamics simulation package, to introduce spin to the flexible shot model. The original one or two piece flexible shot model was based on finite element beam theory, and therefore spin needed to take into account the moments of inertia at each node. Each node is therefore treated as an independently spinning body, each with its own spinning axes which can be related to the next node so that stiffness forces between them can be calculated. The stiffness coefficients are recalculated as deformation takes place, which is particularly important with long rod penetrators because of the high accelerations involved which induce buckling moments in the rod as it bends. The relationship between the nodes and the stiffness coefficients is maintained by updating the direction cosines for each node, plus a set for the overall beam.The final model has been validated against known rigid model cases, by increasing stiffness until flexing is reduced. Comparisons have then been made with standard whirling cases.
Vibration Measurements by Tracking Laser Doppler Vibrometer on Automotive Components
Authors: Castellini P. 
Published: January 2014

This paper describes the application of a Tracking Laser Doppler Vibrometer (TLDV) to the measurement of vibration of some typical automotive component.After a presentation and discussion of the measurement technique, the attention is focused on the development of specific version optimised for each application.The first component analysed is the sidewall of a tire during its rotation in a typical drum test‐bench. An optimised version of the TLDV was developed for the specific application adding a trajectory assessment tool based on image analysis, in order to fulfil the accuracy specifications imposed by tire manufacturer.The second automotive component is a timing belt.This application presents problems related to the high‐speed linear motion and to data processing for noise rejection. The third application is on windscreen wipers. In this case the tracking approach fully demonstrate his capabilities, representing the only technique able to give information in the time domain on the dynamic behaviour of the rubber blade in operative conditions.All the application shows as the TLDV allows to obtain realistic results on the dynamic characteristics under simulated operative conditions.A Lagrangian approach was adopted: data were acquired with the target in continuously changing conditions and that impose a not traditional approach on LDV data such as a joint time‐frequency analysis.
A New Vibration Measurement Procedure for On‐Line Quality Control of Electronic Devices
Authors: Revel Gian Marco 
Published: January 2014

In this paper the problem of experimentally testing the mechanical reliability of electronic components for quality control is approached. In general, many tests are performed on electronic devices (personal computers, power supply units, lamps, etc.), according to the relevant international standards (IEC), in order to verify their resistance to shock and vibrations, but these are mainly “go no‐go” experiments, performed on few samples taken from the production batches.The idea here proposed is to improve the efficiency of these tests by using electro‐optic techniques for the measurement of the vibration behaviour of the components under known excitation. This would allow the on‐line testing of a high percentage of the production and would be useful to give important feedback to the design process.Scanning laser Doppler vibrometry seems to be a valuable solution for this problem, thanks to its capabilities of measuring several spatially‐defined points on a vibrating object with reduced testing time for on‐line application, with high sensitivity and accuracy, non‐intrusivity and with any kind of excitation signal. Experimental tests are performed on a power supply: the results show the effectiveness of the proposed approach. The metrological problems connected with the on‐line implementation are also discussed.
Pergolide Mesilate May Improve Fatigue in Patients with Parkinson’s Disease
Authors: Abe Kazuo , Takanashi Mayako , Yanagihara Takehiko , Sakoda Sabro 
Published: January 2014

Objectives: Fatigue is a complaint frequently encountered among patients with Parkinson’s disease (PD). Considering the possible relationship between fatigue and dopaminergic dysfuncion, we investigated the effect of pergolide mesilate (a D2 and D1 dopamine receptor agonist) and bromocriptine (a D2 selective dopamine receptor) in patients with PD.Methods: We evaluated 41 patients with PD and controls. We assessed the degree of fatigue by using a fatigue scale. The severity of PD was evaluated by the Hoehn and Yahr Scale and the unified Parkinson’s disease rating scale (UPDRS).Results: After five weeks from prescription, patients taking pergolide mesilate showed significant improvement in the fatigue scale (from 5.1 ± 0.7 to 4.4 ± 0.55, p < 0.05, ) but patients taking bromocriptine did not (from 4.8 ± 0.9 to 4.7 ± 0.8).Conclusions: Our study suggested the possibility of functional correlation between fatigue and D1 receptor in patients with PD.
Lexical Processes and Eye Movements in Neglect Dyslexia
Authors: di Pellegrino Giuseppe , Làdavas Elisabetta , Galletti Claudio 
Published: January 2014

Neglect dyslexia is a disturbance in the allocation of spatial attention over a letter string following unilateral brain damage. Patients with this condition may fail to read letters on the contralesional side of an orthographic string. In some of these cases, reading is better with words than with non‐words. This word superiority effect has received a variety of explanations that differ, among other things, with regard to the spatial distribution of attention across the letter string during reading. The primary goal of the present study was to explore the interaction between attention and lexical processes by recording eye movements in a patient (F.C.) with severe left neglect dyslexia who was required to read isolated word and non‐word stimuli of various length.F.C.’s ocular exploration of orthographic stimuli was highly sensitive to the lexical status of the letter string. We found that: (1) the location to which F.C. directed his initial saccade (obtained approximately 230 ms post‐stimulus onset) differed between word and non‐word stimuli; (2) the patient spent a greater amount of time fixating the contralesional side of word than non‐word strings. Moreover, we also found that F.C. failed to identify the left letters of a string despite having fixated them, thus showing a clear dissociation between eye movement responses and conscious access to orthographic stimuli.Our data suggest the existence of multiple interactions between lexical, attentional and eye movement systems that occur from very initial stages of visual word recognition.
Integration of Pulsed‐Laser ESPI with Spatial Domain Modal Analysis
Authors: Auweraer H. Van der , Steinbichler H. , Haberstok C. , Freymann R. , Storer D. 
Published: January 2014

The present paper discusses the various critical elements of a modal testing system based on pulsed‐laser holographic ESPI measurements. Such system allows making very high spatial resolution measurements on panel‐like structures at frequencies that are of relevance for the vibro‐acoustic behavior.Next to the optical parts, the integration with the modal analysis procedure, including the integration of geometry and response information, is reviewed. The ESPI based Image‐domain frequency response functions are accumulated frequency by frequency. Special attention is paid to the modal parameter extraction of the large DOF number data, for which a special data reduction scheme was developed. The approach has been applied to several case studies related to car panels. The research was conducted in the context of the Brite/Euram project SALOME and the EUREKA project HOLOMODAL.
Ruggedizing Printed Circuit Boards Using a Wideband Dynamic Absorber
Authors: Ho V.C. , Veprik A.M. , Babitsky V.I. 
Published: January 2014

The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB) for use in hostile industrial and military environment are either insufficient or expensive. This paper addresses a novel approach towards ruggedizing commercial‐off‐the‐shelf PCBs using a miniature wideband dynamic absorber. The optimisation technique used relies on the experimentally measured vibration spectra and complex receptance of the original PCB.The analytical study and full‐scale experiment show that an optimised wideband dynamic absorber with the mass of only 15% relative to the total mass of the PCB is quite capable of the essential suppression of all relevant resonant responses of the PCB under shock, wideband random and sinusoidal vibration with variable frequency.