bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Model Updating Using FRF Measurements
Authors: Asma Farid , Bouazzouni Amar
Published: January 2014

This study presents a new updating method based on measured frequency response functions. The objective function of the minimization procedure is formed by the difference between the measured and the analytical frequency responses. The updating parameters are the correction coefficients related to each the elementary mass and stiffness matrices. While making use of a number of incomplete measurements for some frequencies, one builds a non‐linear system of equations. The linearisation of the numerical system leads to an iterative procedure. An intrinsic frequency parametrization is proposed in order to accelerate the convergence of the iterative system. The obtained results are comparable with those of the known least squares methods.
Whole‐Word Phonological Representations of Disyllabic Words in the Chinese Lexicon: Data From Acquired Dyslexia
Authors: Law Sam-Po , Wong Winsy , Chiu Karen M. Y.
Published: January 2014

This study addresses the issue of the existence of whole‐word phonological representations of disyllabic and multisyllabic words in the Chinese mental lexicon. A Cantonese brain‐injured dyslexic individual with semantic deficits, YKM, was assessed on his abilities to read aloud and to comprehend disyllabic words containing homographic heterophonous characters, the pronunciation of which can only be disambiguated in word context. Superior performance on reading to comprehension was found. YKM could produce the target phonological forms without understanding the words. The dissociation is taken as evidence for whole‐word representations for these words at the phonological level. The claim is consistent with previous account for discrepancy of the frequencies of tonal errors between reading aloud and object naming in Cantonese reported of another case study of similar deficits. Theoretical arguments for whole‐word form representations for all multisyllabic Chinese words are also discussed.
Diagnosis and Model Based Identification of a Coupling Misalignment
Authors: Pennacchi P. , Vania A.
Published: January 2014

This paper is focused on the application of two different diagnostic techniques aimed to identify the most important faults in rotating machinery as well as on the simulation and prediction of the frequency response of rotating machines. The application of the two diagnostics techniques, the orbit shape analysis and the model based identification in the frequency domain, is described by means of an experimental case study that concerns a gas turbine‐generator unit of a small power plant whose rotor‐train was affected by an angular misalignment in a flexible coupling, caused by a wrong machine assembling. The fault type is identified by means of the orbit shape analysis, then the equivalent bending moments, which enable the shaft experimental vibrations to be simulated, have been identified using a model based identification method. These excitations have been used to predict the machine vibrations in a large rotating speed range inside which no monitoring data were available. To the best of the authors′ knowledge, this is the first case of identification of coupling misalignment and prediction of the consequent machine behaviour in an actual size rotating machinery. The successful results obtained emphasise the usefulness of integrating common condition monitoring techniques with diagnostic strategies.
Letter Form as a Constraint for Errors in Neglect Dyslexia and Letter Position Dyslexia
Authors: Friedmann Naama , Gvion Aviah
Published: January 2014

Does letter‐form constrain errors in peripheral dyslexia? In Hebrew, 5 of the 22 letters have two different letter forms, one is used only when the letter occurs in word‐final position, the other form is used in initial and middle positions. Is the information on final‐forms encoded in the letter identity information and used for word identification, or is it discarded? The current research explored this question through the effect of final vs. non final letter form on the error pattern in neglect dyslexia (neglexia) and letter position dyslexia (LPD). Left word‐based neglexia results in errors of omission, substitution and addition of letters in the left side of words, which in Hebrew is the end of the word. We examined whether final letter form blocks the addition of letters to the end of the word and whether omissions of letters after letters in non‐final form are avoided. The predominant error type in LPD is migration of letters within words. We tested whether migrations also occur when they cause form change of either final‐form letters that move to middle position or middle‐form letters that move to final position. These questions were assessed in both acquired and developmental neglexia and LPD. The results indicated a strong effect of final letter‐form on acquired neglexia and on acquired and developmental LPD, which almost completely prevented form‐changing errors. This effect was not found in developmental neglexia, where words that end in final‐form letters were actually more impaired than other words, probably because final‐form letters appear only on the neglected side of the word for Hebrew‐reading children with left developmental neglexia. These data show that early visuo‐orthographic analysis is sensitive to final letter form and that final letter form constrains errors in peripheral dyslexia.
Auditory Hallucinations in Acute Stroke
Authors: Lampl Yair , Lorberboym Mordechai , Gilad Ronit , Boaz Mona , Sadeh Menachem
Published: January 2014

Auditory hallucinations are uncommon phenomena which can be directly caused by acute stroke, mostly described after lesions of the brain stem, very rarely reported after cortical strokes. The purpose of this study is to determine the frequency of this phenomenon. In a cross sectional study, 641 stroke patients were followed in the period between 1996–2000. Each patient underwent comprehensive investigation and follow‐up. Four patients were found to have post cortical stroke auditory hallucinations. All of them occurred after an ischemic lesion of the right temporal lobe. After no more than four months, all patients were symptom‐free and without therapy. The fact the auditory hallucinations may be of cortical origin must be taken into consideration in the treatment of stroke patients. The phenomenon may be completely reversible after a couple of months.
The Selective Impairment of the Phonological Output Buffer: Evidence From a Chinese Patient
Authors: Shu Hua , Xiong Hanzhong , Han Zaizhu , Bi Yanchao , Bai Xiaoli
Published: January 2014

We present a Chinese‐speaking patient, SJ, who makes phonological errors across all tasks involving oral production. Detailed analyses of the errors across different tasks reveal that the patterns are very similar for reading, oral picture naming, and repetition tasks, which are also comparable to the error patterns of the phonological buffer deficit cases reported in the literature. The nature of the errors invites us to conclude that the patient′s phonological output buffer is selectively impaired. Different from previously reported cases, SJ′s deficits in oral production tasks are not accompanied by a similar impairment of writing performance. We argue that this dissociation is evidence that the phonological output buffer is not involved in writing Chinese words. Furthermore, the majority of SJ′s errors occur at the onset of a syllable, indicating that the buffer has a structure that makes the onset more prone to impairment.
Optimization of Classical Hydraulic Engine Mounts Based on RMS Method
Authors: Christopherson J. , Jazar G. Nakhaie
Published: January 2014

Based on RMS averaging of the frequency response functions of the absolute acceleration and relative displacement transmissibility, optimal parameters describing the hydraulic engine mount are determined to explain the internal mount geometry. More specifically, it is shown that a line of minima exists to define a relationship between the absolute acceleration and relative displacement transmissibility of a sprung mass using a hydraulic mount as a means of suspension. This line of minima is used to determine several optimal systems developed on the basis of different clearance requirements, hence different relative displacement requirements, and compare them by means of their respective acceleration and displacement transmissibility functions. In addition, the transient response of the mount to a step input is also investigated to show the effects of the optimization upon the time domain response of the hydraulic mount.
Simulation of Asymmetric Lamb Waves for Sensing and Actuation in Plates
Authors: Ghoshal A. , Martin W.N. , Schulz M.J. , Prosser W.H. , Chattopadhyay A.
Published: January 2014

Two approaches used for monitoring the health of thin aerospace structures are active interrogation and passive monitoring. The active interrogation approach generates and receives diagnostic Lamb waves to detect damage, while the passive monitoring technique listens for acoustic waves caused by damage growth. For the application of both methods, it is necessary to understand how Lamb waves propagate through a structure. In this paper, a Physics‐Based Model (PBM) using classical plate theory is developed to provide a basic understanding of the actual physical process of asymmetric Lamb mode wave generation and propagation in a plate. The closed‐form model uses modal superposition to simulate waves generated by piezoceramic patches and by simulated acoustic emissions. The generation, propagation, reflection, interference, and the sensing of the waves are represented in the model, but damage is not explicitly modeled. The developed model is expected to be a useful tool for the Structural Health Monitoring (SHM) community, particularly for studying high frequency acoustic wave generation and propagation in lieu of Finite Element models and other numerical models that require significant computational resources. The PBM is capable of simulating many possible scenarios including a variety of test cases, whereas experimental measurements of all of the cases can be costly and time consuming. The model also incorporates the sensor measurement effect, which is an important aspect in damage detection. Continuous and array sensors are modeled, which are efficient for measuring waves because of their distributed nature.
The Extended Finite Element Method for Dynamic Fractures
Authors: Zi Goangseup , Chen Hao , Xu Jingxiao , Belytschko Ted
Published: January 2014

A method for modelling arbitrary growth of dynamic cracks without remeshing is presented. The method is based on a local partition of unity. It is combined with level sets, so that the discontinuities can be represented entirely in terms of nodal data. This leads to a simple method with clean data structures that can easily be incorporated in general purpose software. Results for a mixed‐mode dynamic fracture problem are given to demonstrate the method.
Experimental Snap Loading of Synthetic Ropes
Authors: Hennessey C.M. , Pearson N.J. , Plaut R.H.
Published: January 2014

Large tensile forces, known as snap loads, can occur when a slack rope becomes taut. Such forces may damage the rope or masses connected to it. Experiments are described in which one end of a rope is attached to the top of a drop tower and the bottom end is attached to a weight. The weight is raised to a certain height and then released. The force at the top of the rope and the acceleration of the weight are recorded during the first snap load that occurs. Repeated drop tests are performed on each rope. The effects of the type of rope, drop height, drop weight, whether the rope has been subjected to static precycling, and the number of previous dynamic tests are examined. A mathematical model is proposed for the rope force as a function of the displacement and velocity of the weight.
Multiple Levels of Letter Representation in Written Spelling: Evidence From a Single Case of Dysgraphia with Multiple Deficits
Authors: de Partz Marie-Pierre , Lochy Aliette , Pillon Agnesa
Published: January 2014

In this paper, we report a detailed analysis of the impaired performance of a dysgraphic individual, AD, who produced similar rates of letter‐level errors in written spelling, oral spelling, and typing. We found that the distribution of various letter error types displayed a distinct pattern in written spelling on the one hand and in oral spelling and typing on the other. In particular, noncontextual letter substitution errors (i.e., errors in which the erroneous letter that replaces the target letter does not occur elsewhere within the word) were virtually absent in oral spelling and typing and mainly found in written spelling. In contrast, letter deletion errors and multiple‐letter errors were typically found in oral spelling and very exceptional in written spelling. Only contextual letter substitution errors (i.e., errors in which the erroneous letter that replaces the target letter is identical to a letter occurring earlier or later in the word) were found in similar proportions in the three tasks. We argue that these contrasting patterns of letter error distribution result from damage to two distinct levels of letter representation and processing within the spelling system, namely, the amodal graphemic representation held in the graphemic buffer and the letter form representation computed by subsequent writing‐specific processes. Then, we examined the relationship between error and target in the letter substitution errors produced in written and oral spelling and found evidence that distinct types of letter representation are processed at each of the hypothetized levels of damage: symbolic letter representation at the graphemic level and representation of the component graphic strokes at the letter form processing level.
Longitudinally Vibrating Elastic Rods with Locally and Non‐Locally Reacting Viscous Dampers
Authors: Yüksel Şefaatdin , Dalli Uğur
Published: January 2014

Eigencharacteristics of a longitudinally vibrating elastic rod with locally and non‐locally reacting damping are analyzed. The rod is considered as a continuous system and complex eigenfrequencies are determined as solution of a characteristic equation. The variation of the damping ratios with respect to damper locations and damping coefficients for the first four eigenfrequencies are obtained. It is shown that at any mode of locally or non‐locally damped elastic rod, the variation of damping ratio with damper location is linearly proportional to absolute value of the mode shape of undamped system. It is seen that the increasing damping coefficient does not always increase the damping ratio and there are optimal values for the damping ratio. Optimal values for external damping coefficients of viscous dampers and locations of the dampers are presented.
Predicting the Dynamic Behaviour of Hydrobushings
Authors: Gil-Negrete N. , Rivas A. , Viñolas J.
Published: January 2014

A novel and promising approach for the prediction of the dynamic stiffness of hydrobushings is presented, combining Finite Element and CFD methods. The rubber structure of the mount is modelled in ABAQUS and the flow of fluid through the inertia track is calculated in FLUENT. The obtained results from the latter simulation are incorporated in the finite element code for the final stiffness prediction. The calculation is very sensitive to both rubber and fluid properties. The dynamic behaviour of rubber material has accurately been characterised with a new simple shear specimen in a forced non‐resonant test.

Satisfactory results are obtained when comparing numerical simulations to experimental tests in a practical application. Discrepancies between simulations and tests are mainly due to the simplifications assumed when creating the model. Nevertheless, stiffness of the mount is well predicted and so is the damping, although the frequency at which its maximum value is achieved is underestimated by 4–6 Hz, result that could be improved if non‐stationary boundary conditions were considered when solving the fluid flow and incorporating it to the finite element code.
Posterior Cortical Atrophy: Clinical Presentation and Cognitive Deficits Compared to Alzheimer’s Disease
Authors: Charles Raquel F. , Hillis Argye E.
Published: January 2014

Background: Posterior cortical atrophy (PCA) is an uncommon dementia syndrome with initial manifestations of visual dysfunction and preservation of memory and language until late in the disease. Since prognosis and management differ from typical Alzheimer’s disease (tAD), clinical tests to distinguish PCA from tAD are needed.

Methods: Fifteen PCA cases and 15 tAD cases, defined by clinical and MRI criteria, were compared by present symptoms and scores on four cognitive tests.

Results: Symptoms of visual disturbance and dyslexia were more commonly reported in PCA cases (p = 0.0001 and p = 0.006, respectively), and memory loss was more commonly reported in tAD (p = 0.006). Patients with PCA were less accurate on the Cortical Vision Screening Test (t = 6.0; p < 0.001) and in copying the Rey‐Osterreith Complex Figure (t = 6.0; p < 0.001), in comparison to the tAD group. Memory, evaluated by the Rey Auditory Verbal Learning Test, was impaired in both groups; however, delayed recall was more impaired in the tAD group (t = 2.5; p = 0.03).

Conclusion: Compared to patients with tAD, patients with PCA are more likely to present to their providers with symptoms of visual dysfunction. Performance on simple tests of visual perception and copying can be used to distinguish the two disorders even a few years after initial symptoms.
D8/17 Monoclonal Antibody: An Unclear Neuropsychiatric Marker
Authors: Morer Astrid , Viñas Odette , Lázaro Luisa , Bosch Jordi , Toro Josep , Castro Josefina
Published: January 2014

Objective: It has been hypothesized that monoclonal antibody D8/17 identifies a B lymphocyte antigen with expanded expression in patients with rheumatic fever, childhood onset obsessive‐compulsive disorder (OCD), Tourette syndrome (TS) or prepubertal anorexia nervosa (AN). Our purpose was to replicate these studies in a Spanish population and to determine whether D8/17 identifies a subgroup of these patients, focusing especially on OCD subjects.

Method: D8/17 expression was assessed with double immunofluorescence and flow cytometry using monoclonal immunoglobulin M (IgM) in three groups of patients with diagnoses of OCD (n = 17), TS (n = 5) and prepubertal AN (n = 5), recruited during 2001.

Results: In the sample studied the average percentage of B cells expressing D8/17 was 4.8%. The D8/17 positive proportion of B lymphocytes was above 11% in only two out of 17 OCD patients (7.4% of total sample) and in none of the TS or prepubertal AN patients. No statistically significant differences were found in mean percentages of D8/17 between the three groups.

Conclusions: In the sample studied the expression of D8/17 in B cells was very low and the great majority of patients were negative for the D8/17 marker. The molecular characterization of D8/17 would be a major step forward in clarifying its implication for these diseases.
Reaction Time of Motor Responses in Two‐Stimulus Paradigms Involving Deception and Congruity with Varying Levels of Difficulty
Authors: Vendemia Jennifer M. C. , Buzan Robert F. , Simon-Dack Stephanie L.
Published: January 2014

Deception research has focused on identifying peripheral nervous system markers while ignoring cognitive mechanisms underlying those markers. Cognitive theorists argue that the process of deception may involve such constructs as attentional capture, working memory load, or perceived incongruity with memory, while psychophysiologists argue for stimulus salience, arousal, and emotion. Three studies were conducted to assess reaction time (RT) in relation to deception, response congruity, and preparedness to deceive. Similar to a semantic verification task, participants evaluated sentences that were either true or false, and then made truthful or deceptive evaluations of the sentence’s base truth‐value. Findings indicate that deceptive responses have a longer RT than truthful responses, and that this relationship remains constant across response type and preparedness to deceive. The authors use these findings in preliminary support of a comprehensive cognitive model of deception.
Modal Perturbation Method for the Dynamic Characteristics of Timoshenko Beams
Authors: Lou Menglin , Duan Qiuhua , Chen Genda
Published: January 2014

Timoshenko beams have been widely used in structural and mechanical systems. Under dynamic loading, the analytical solution of a Timoshenko beam is often difficult to obtain due to the complexity involved in the equation of motion. In this paper, a modal perturbation method is introduced to approximately determine the dynamic characteristics of a Timoshenko beam. In this approach, the differential equation of motion describing the dynamic behavior of the Timoshenko beam can be transformed into a set of nonlinear algebraic equations. Therefore, the solution process can be simplified significantly for the Timoshenko beam with arbitrary boundaries. Several examples are given to illustrate the application of the proposed method. Numerical results have shown that the modal perturbation method is effective in determining the modal characteristics of Timoshenko beams with high accuracy. The effects of shear distortion and moment of inertia on the natural frequencies of Timoshenko beams are discussed in detail.
Vibration Excitation and Control of a Pedestrian Walkway by Individuals and Crowds
Authors: Brownjohn James Mark William , Fu Tao Neng
Published: January 2014

As part of a continuing study on effects of humans on loading and dynamic response of footbridges, a steel frame walkway has been the subject of studies on the effects of multiple pedestrians with respect to loading and response mitigation. Following finite element modeling and experimental modal analysis to identify the low frequency vibration modes likely to be excited by normal walking, the variation of response with pedestrian density and of system damping and natural frequency with occupancy by stationary pedestrians were both studied. The potentially mitigating effect of stationary occupants is still not well understood and the study included direct measurement of damping forces and absorbed energy using a force plate. The various tests showed that energy dissipation measured directly was consistent with the observed change in damping, that vertical and lateral response both varied approximately with square root of number of pedestrians, and that the simple model of a human as a single mass‐spring‐damper system may need to be refined to fit observed changes in modal parameters with a crowd of humans present. Modal parameter changes with moving pedestrians were small compared to those with stationary pedestrians indicating that within limits, modal parameters for the empty structure could be used in analysis.
Acquired Dyslexia in Spanish: A Review and Some Observations on a New Case of Deep Dyslexia
Authors: Davies Robert , Cuetos Fernando
Published: January 2014

Readers and writers of Spanish use an orthography that is highly transparent. It has been proposed that readers of Spanish can rely on grapheme‐phoneme correspondences, alone, to access meaning or phonology from print. In recent years, a number of case studies have yielded evidence inconsistent with this idea. We review these studies with particular focus on those that report evidence for reading based on direct lexical mappings between print, orthographic representations, and meaning or phonology. We report a new case of acquired literacy impairment in Spanish, MJ, who presents a pattern of preserved abilities and deficits symptomatic of deep dyslexia. The patient is unable to read nonwords, but can read a substantial number of words. Her reading is characterized by the production of semantic, visual, and derivational errors. We argue that MJ has a deficit in her lexical selection ability, common to both her reading and her naming problems. We propose that MJ, and the other cases we review, demonstrate that lexical reading is adopted by skilled readers even in a transparent language.
Anti‐Swing Control of Gantry and Tower Cranes Using Fuzzy and Time‐Delayed Feedback with Friction Compensation
Authors: Omar H.M. , Nayfeh A.H.
Published: January 2014

We designed a feedback controller to automate crane operations by controlling the load position and its swing. First, a PD tracking controller is designed to follow a prescribed trajectory. Then, another controller is added to the control loop to damp the load swing. The anti‐swing controller is designed based on two techniques: a time‐delayed feedback of the load swing angle and an anti‐swing fuzzy logic controller (FLC). The rules of the FLC are generated by mapping the performance of the time‐delayed feedback controller. The same mapping method used for generating the rules can be applied to mimic the performance of an expert operator. The control algorithms were designed for gantry cranes and then extended to tower cranes by considering the coupling between the translational and rotational motions. Experimental results show that the controller is effective in reducing load oscillations and transferring the load in a reasonable time. To experimentally validate the theory, we had to compensate for friction. To this end, we estimated the friction and then applied a control action to cancel it. The friction force was estimated by assuming a mathematical model and then estimating the model coefficients using an off‐line identification technique, the method of least squares (LS).
Vibration Control Systems for Sensitive Equipment: Limiting Performance and Optimal Design
Authors: Ryaboy V.M.
Published: January 2014

As vibration control requirements become increasingly stringent, designers and users of vibration control equipment turn to devices and systems combining various physical mechanisms. Subsystems based on different physical effects can be combined to achieve the optimal performance for the application. Building an optimal product line that would cover a wide field of applications by combining several products, as opposed to creating one optimal device for a particular application, presents an optimum vibration control problem. This paper reviews optimum vibration control problems based on the idea of limiting performance, and discusses recent development of vibration control devices.
An Experimental Assessment of Transverse Adaptive Fir Filters as Applied to Vibrating Structures Identification
Authors: Castello Daniel A. , Rochinha Fernando A.
Published: January 2014

The present work is aimed at assessing the performance of adaptive Finite Impulse Response (FIR) filters on the identification of vibrating structures. Four adaptive algorithms were used: Least Mean Squares (LMS), Normalized Least Mean Squares (NLMS), Transform‐Domain Least Mean Squares (TD – LMS) and Set‐Membership Binormalized Data‐Reusing LMS Algorithm (SM – BNDRLMS). The capability of these filters to perform the identification of vibrating structures is shown on real experiments. The first experiment consists of an aluminum cantilever beam containing piezoelectric sensors and actuators and the second one is a steel pinned‐pinned beam instrumented with accelerometers and an electromechanical shaker.
Stuttering Due To Ischemic Stroke
Authors: Sahin Huseyin Alparslan , Krespi Yakup , Yilmaz Ahmet , Coban Oguzhan
Published: January 2014

Acquired stuttering is a disorder of the fluency of speech. The mechanism underlying stuttering is unknown. It may occur after bilateral and unilateral cortical or subcortical brain damage. We report two cases who had stuttering resulting from left parietal infarction.
A Foreign Speech Accent in a Case of Conversion Disorder
Authors: Verhoeven Jo , Mariën Peter , Engelborghs Sebastiaan , D’Haenen Hugo , De Deyn Peter
Published: January 2014

Objective: The aim of this paper is to report the psychiatric, neuroradiological and linguistic characteristics in a native speaker of Dutch who developed speech symptoms which strongly resemble Foreign Accent Syndrome. Background: Foreign Accent Syndrome is a rare speech production disorder in which the speech of a patient is perceived as foreign by speakers of the same speech community. This syndrome is generally related to focal brain damage. Only in few reported cases the Foreign Accent Syndrome is assumed to be of psychogenic and/or psychotic origin. Method: In addition to clinical and neuroradiological examinations, an extensive test battery of standardized neuropsychological and neurolinguistic investigations was carried out. Two samples of the patient′s spontaneous speech were analysed and compared to a 500,000‐words reference corpus of 160 normal native speakers of Dutch. Results: The patient had a prominent French accent in her pronunciation of Dutch. This accent had persisted over the past eight years and has become progressively stronger. The foreign qualities of her speech did not only relate to pronunciation, but also to the lexicon, syntax and pragmatics. Structural as well as functional neuroimaging did not reveal evidence that could account for the behavioural symptoms. By contrast psychological investigations indicated conversion disorder. Conclusions: To the best of our knowledge this is the first reported case of a foreign accent like syndrome in conversion disorder.
The Validity of the Hospital Anxiety and Depression Scale and the Geriatric Depression Scale in Parkinson’s Disease
Authors: Mondolo Federica , Jahanshahi Marjan , Granà Alessia , Biasutti Emanuele , Cacciatori Emanuela , Di Benedetto Paolo
Published: January 2014

We assessed the concurrent validity of the Hospital Anxiety and Depression Scale (HADS) and the Geriatric Depression Scale (GDS) against the Hamilton Rating Scale for Depression (Ham‐D) in patients with Parkinson’ disease (PD). Forty‐six non‐demented PD patients were assessed by a neurologist on the Ham‐D. Patients also completed four mood rating scales: the HADS, the GDS, the VAS and the Face Scale. For the HADS and the GDS, Receiver Operating Characteristics (ROC) curves were obtained and the positive and negative predictive values (PPV, NPV) were calculated for different cut‐off scores. Maximum discrimination between depressed and non‐depressed PD patients was reached at a cut‐off score of 10/11 for both the HADS and the GDS. At the same cut‐off score of 10/11 for both the HADS and the GDS, the high sensitivity and NPV make these scales appropriate screening instruments for depression in PD. A high specificity and PPV, which is necessary for a diagnostic test, was reached at a cut‐off score of 12/13 for the GDS and at a cut‐off score of 11/12 for the HADS. The results indicate the validity of using the HADS and the GDS to screen for depressive symptoms and to diagnose depressive illness in PD.
Neuroprotection and Stroke Rehabilitation: Modulation and Enhancement of Recovery
Authors: Romero José Rafael , Babikian Viken L. , Katz Douglas I. , Finklestein Seth P.
Published: January 2014

Recent advances in research are modifying our view of recovery after nervous system damage. New findings are changing previously held concepts and providing promising avenues for treatment of patients after stroke. This review discusses mechanisms of neuronal injury after brain ischemia and the attempts to study neuroprotection options based on such mechanisms. It also considers measures available at present to improve outcome after stroke and presents new areas of research, particularly stimulation techniques, neurogenesis and trophic factors to enhance recovery. In order to improve outcomes, medications that may be detrimental to recovery should be avoided, while symptomatic therapy of problems such as depression, pain syndromes and spasticity may contribute to better results. Continued surveillance and early treatment of complications associated with acute stroke, along with supportive care remain the mainstay of treatment for stroke patients in the recovery phase. Present research on limiting brain damage and improving recovery and plasticity enhance the prospects for better clinical treatments to improve recovery after stroke.
Neuropharmacological Treatment of Mental Dysfunction in Parkinson’s Disease
Authors: McNamara Patrick , Durso Raymon
Published: January 2014

Many patients with Parkinson′s Disease (PD) experience significant cognitive and mood impairment ‐even early in the course of the disease. These mental impairments are only partially responsive to levodopa treatment and are often as disabling as the motor impairment, particularly in mid and late stages of the disease. Investigators have recently begun a search for new agents that can effectively treat mental dysfunction of PD. Although there have been only a handful of properly controlled clinical trials of interventions targeted at amelioration of mental dysfunction in PD, progress has been made. Based on the available evidence, targeting catecholaminergic and cholinergic function may be an effective strategy for amelioration of cognitve, mood and psychiatric disturbances in PD.
Dynamic Stability of a Circular Pre‐Stressed Elastic Orthotropic Plate Subjected to Shock Excitation
Authors: Rossikhin Yuriy A. , Shitikova Marina V.
Published: January 2014

The problem on low‐velocity impact of an elastic body upon a pre‐stressed circular orthotropic plate possessing cylindrical anisotropy is considered. The dynamic behavior of the plate is described by equations taking the rotary inertia and transverse shear deformations into account. Longitudinal compressing forces are uniformly distributed along the plate’s median plane. Contact interaction is modeled by a linear spring, and a force arising in it is the linear approximation of Herts’z contact force. During the shock interaction of the impactor with the plate, the waves which are the surfaces of strong discontinuity are generated in the plate and begin to propagate. Behind the fronts of these waves, the solution is constructed in terms of ray series, which coefficients are the different order discontinuities in partial time‐derivatives of the desired functions, and a variable is the time elapsed after the wave arrival at the plate’s point under consideration. The ray series coefficients are determined from recurrent equations within accuracy of arbitrary constants, which are then determined from the conditions of dynamic contact interaction of the impactor with the target. The found arbitrary constants allow one to construct the solution both within and out of the contact region. The analysis of the solution obtained enables one to find out the new effect and to make the inference that under a certain critical magnitude of the compression force the orthotropic plate goes over into the critical state, what is characterized by ‘locking’ the shear wave within the contact region, resulting in plate damage within this zone as soon as the compression force exceeds its critical value.
Coupling Sensing Hardware with Data Interrogation Software for Structural Health Monitoring
Authors: Farrar Charles R. , Allen David W. , Park Gyuhae , Ball Steven , Masquelier Michael P.
Published: January 2014

The process of implementing a damage detection strategy for aerospace, civil and mechanical engineering infrastructure is referred to as structural health monitoring (SHM). The authors′ approach is to address the SHM problem in the context of a statistical pattern recognition paradigm. In this paradigm, the process can be broken down into four parts: (1) Operational Evaluation, (2) Data Acquisition and Cleansing, (3) Feature Extraction and Data Compression, and (4) Statistical Model Development for Feature Discrimination. These processes must be implemented through hardware or software and, in general, some combination of these two approaches will be used. This paper will discuss each portion of the SHM process with particular emphasis on the coupling of a general purpose data interrogation software package for structural health monitoring with a modular wireless sensing and processing platform. More specifically, this paper will address the need to take an integrated hardware/software approach to developing SHM solutions.
Hydraulic Power Plant Machine Dynamic Diagnosis
Authors: Poll Hans Günther , Zanutto José Carlos , Ponge-Ferreira Walter
Published: January 2014

A method how to perform an entire structural and hydraulic diagnosis of prototype Francis power machines is presented and discussed in this report. Machine diagnosis of Francis units consists on a proper evaluation of acquired mechanical, thermal and hydraulic data obtained in different operating conditions of several rotary and non rotary machine components. Many different physical quantities of a Francis machine such as pressure, strains, vibration related data, water flow, air flow, position of regulating devices and displacements are measured in a synchronized way so that a relation of cause an effect can be developed for each operating condition and help one to understand all phenomena that are involved with such kind of machine. This amount of data needs to be adequately post processed in order to allow correct interpretation of the machine dynamics and finally these data must be compared with the expected calculated data not only to fine tuning the calculation methods but also to accomplish fully understanding of the influence of the water passages on such machines. The way how the power plant owner has to operate its Francis machines, many times also determined by a central dispatcher, has a high influence on the fatigue life time of the machine components. The diagnostic method presented in this report helps one to understand the importance of adequate operation to allow a low maintenance cost for the entire power plant. The method how to acquire these quantities is discussed in details together with the importance of correct sensor balancing, calibration and adequate correlation with the physical quantities. Typical results of the dynamic machine behavior, with adequate interpretation, obtained in recent measurement campaigns of some important hydraulic turbines were presented. The paper highlights the investigation focus of the hydraulic machine behavior and how to tailor the measurement strategy to accomplish all goals. Finally some typical recommendations based on the experience obtained on previous diagnostic reports of Francis turbines are performed in order to allow a better and safe operation of these power plant units.
Faults Identification and Corrective Actions in Rotating Machinery at Rated Speed
Authors: Bachschmid Nicolò , Pennacchi Paolo
Published: January 2014

Malfunction identification in rotor systems by means of a model based approach in the frequency domain during long lasting speed transients (coast‐down procedures in large turbo‐generators), where a huge amount of vibration data at different rotating speeds is usually collected, has proved to be very effective. This paper explores the possibility to adapt this method to the situation when the vibration data are available at one rotating speed only, which in real machines is generally the normal operating speed. It results that single speed fault identification can be successful, but does not allow to discriminate between different malfunctions that generate similar symptoms. Neverthless the identification results can be used to define corrective balancing masses.
A New Technique to Identify Arbitrarily Shaped Noise Sources
Authors: Tenenbaum Roberto A. , Magalhães Marcelo Bruno S.
Published: January 2014

Acoustic intensity is one of the available tools for evaluating sound radiation from vibrating bodies. Active intensity may, in some situations, not give a faithful insight about how much energy is in fact carried into the far field. It was then proposed a new parameter, the supersonic acoustic intensity, which takes into account only the intensity generated by components having a smaller wavenumber than the acoustic one. However, the method is only efective for simple sources, such as plane plates, cylinders and spheres. This work presents a new technique, based on the Boundary Elements Method and the Singular Value Decomposition, to compute the supersonic acoustic intensity for arbitrarily shaped sources. The technique is based in the Kirchoff‐Helmholtz equation in a discretized approach, leading to a radiation operator that relates the normal velocity on the source′s surface mesh with the pressure at grid points located in the field. Then, the singular value decomposition technique is set to the radiation operator and a cutoff criterion is applied to remove non propagating components. Some numerical examples are presented.
Reduction of Contact Forces in a Rotor‐Stator‐System in case of Rubbing through Active Auxiliary Bearing
Authors: Chavez Alvaro , Ulbrich Heinz , Ginzinger Lucas
Published: January 2014

The present manuscript deals with the problem of rotor‐stator rubbing. Due to performance increase in rotating machinery, rubbing processes happen more frequently. These are very complicated mechanisms that lead to high impact loads, vibrations and instability. The authors propose a control technique by using an active auxiliary bearing to overcome the problem of rubbing. The control concept enables a transition of the rotor towards a contact situation (with an auxiliary bearing) without rebounding and loss of contact. To investigate the practical feasibility of this approach, numerical simulation has been used to show that using this control concept the impulse (and contact force respectively) can be significantly decreased. Experiments to validate the theoretical findings are already in progress and will be published soon.
Shock Analysis Method for Systematic Performance Evaluation of Component Embedded in Handheld Electronic Devices
Authors: Chin C.S.
Published: January 2014

It is important to identify the robustness of product (or embedded component inside the product) against shock due to free drop. With the increasing mobile and fast‐paced lifestyle of the average consumer, much is required of the products; such as consumers expect mobile products to continue to operate after drop impact. Since free drop test is commonly used to evaluate the robustness of small component embedded in MP3 player, it is difficult to produce a repeatable shock reading due to highly uncontrolled orientation during the impact on ground. Hence attention has been focus on shock table testing, which produces a higher repeatable result. But it failed to demonstrate the actual shock with the presence of rotational movement due to free drop and also it suffers from a similar limitation of repeatability. From drop to drop, shock tables can vary about ± 5% in velocity change but suitable for making a consistent tracking the product improvement.

Although many test procedure (such as ASTM D3332 [5]) have been written around shock test machines, as a whole, the test perform on the shock tables have no direct correlation over the free‐drop testing. Since both will have some velocity change variability. Some products react more to torsion forces than they do to orthogonal forces, fortunately, due to the size of the product, the exposure to this torsion force is less prominent. Since the intent of lab testing is to re‐create real world events, a unique ways to establish a shock test that encompasses the features of the two tests are needed. Thus, establishing the robustness of the small component against shock due to topple drop at various tilt angle under different drop orientations and platform (such as on the office table), on a MP3 player is needed. This eventually enables a high repeatable and realistic shock testing for product performance evaluation in MP3 player.

There are few advantages of using tilt tester for shock testing. Firstly, close approximations to the actual free drops test with better repeatability. Secondly, it ensures that the shock level is reduced prior to performing a final free drop test (using actual product) and hence reduces the cost. Thirdly, it reduces the number of trials and cycle time needed for shock testing. Lastly, it provides a platform for shock absorber design for component (embedded in the MP3 player) as shown in the Section 3.
An Overview on Primary Progressive Aphasia and Its Variants
Authors: Amici Serena , Gorno-Tempini Maria Luisa , Ogar Jennifer M. , Dronkers Nina F. , Miller Bruce L.
Published: January 2014

We present a review of the literature on Primary Progressive Aphasia (PPA) together with the analysis of neuropschychological and neuroradiologic profiles of 42 PPA patients. Mesulam originally defined PPA as a progressive degenerative disorder characterized by isolated language impairment for at least two years. The most common variants of PPA are: (1) Progressive nonfluent aphasia (PNFA), (2) semantic dementia (SD), (3) logopenic progressive aphasia (LPA). PNFA is characterized by labored speech, agrammatism in production, and/or comprehension. In some cases the syndrome begins with isolated deficits in speech. SD patients typically present with loss of word and object meaning and surface dyslexia. LPA patients have word‐finding difficulties, syntactically simple but accurate language output and impaired sentence comprehension. The neuropsychological data demonstrated that SD patients show the most characteristic pattern of impairment, while PNFA and LPA overlap within many cognitive domains. The neuroimaging analysis showed left perisylvian region involvement. A comprehensive cognitive, neuroimaging and pathological approach is necessary to identify the clinical and pathogenetic features of different PPA variants.
A Novel Engine Mount with Semi‐Active Dry Friction Damping
Authors: Lorenz M. , Heimann B. , Härtel V.
Published: January 2014

In this paper the authors present a semi‐active engine mount with a controllable friction damper. The normal force of the friction contact is applied by an electromagnetic actuator and can be varied dynamically. The nonlinear current‐force‐relation of the actuator is linearized. To account for wear and assembly tolerances, an initialization method is developed, that is based on indirect measurement of the actuators inductance. The friction contact is made up of industrial friction pads and a friction rod of steel. The friction model used is suitable especially for small oscillations of the friction damper. The control policy imitates viscous damping forces that exert a minimum of harmonics. Damping is activated only when necessary. Finally the friction mount is compared to the original mount in a row of test rack experiments and also in the car.
Vibration Analysis of Rotating Tapered Timoshenko Beams by a New Finite Element Model
Authors: Yardimoglu Bulent
Published: January 2014

A new finite element model is developed and subsequently used for transverse vibrations of tapered Timoshenko beams with rectangular cross‐section. The displacement functions of the finite element are derived from the coupled displacement field (the polynomial coefficients of transverse displacement and cross‐sectional rotation are coupled through consideration of the differential equations of equilibrium) approach by considering the tapering functions of breadth and depth of the beam. This procedure reduces the number of nodal variables. The new model can also be used for uniform beams. The stiffness and mass matrices of the finite element model are expressed by using the energy equations. To confirm the accuracy, efficiency, and versatility of the new model, a semi‐symbolic computer program in MATLAB® is developed. As illustrative examples, the bending natural frequencies of non‐rotating/rotating uniform and tapered Timoshenko beams are obtained and compared with previously published results and the results obtained from the finite element models of solids created in ABAQUS. Excellent agreement is found between the results of new finite element model and the other results.