449 research outputs found
A fresh look at the dark side of contemporary careers: toward a realistic discourse
No full textIn this paper we propose that careers be considered as both offering promise and the source of potential disillusionment. While the changing nature of careers and of career management requires a comprehensive perspective to highlight the characteristics and nature of careers in their entirety, most published work predominantly addresses the positive aspects of careers, leaving their darker dynamics almost untouched. We argue that while career scholars tend to clothe such concerns in euphemistic terms, contemporary career experiences may often be quite dark and include a number of undesired consequences. By linking selected career constructs and notions of organizational dark sides, we aim to advance a more balanced framework, offering a career perspective that consists of opportunities versus threats, truth versus untruth and positive versus negative aspects, all of which are inevitably embedded in careers. Thus, we call for career conceptualization and research to be less normatively biased and prescriptive and to be more grounded in reality
Experimental Dispersion identification using a fitted state-space model
No full textAn identification method that can estimate the dispersion relation of waveguides experimentally using an efficient and accurate procedure is presented. The method fits a linear state-space model before resorting to a kinematic wave model in the frequency region near the pre-identified natural frequencies. The eigenvectors, or mode-shapes, are computed at the sensor locations, and based on the reduced-Bloch mode expansion method, the propagation modes are fitted to match the identified vibration mode-shape at these frequencies. Classical methods to identify the dispersion relation from measured data can be computationally expensive and time-consuming, with limited accuracy in cases of multimode propagation. Results show that the fitted dynamic model expands the frequency range of obtained dispersion curves and enhances the speed of computation and accuracy. The method is derived and verified for both lumped and distributed systems, using numerical finite element simulation. Experimental verification is carried out on two acoustical waveguides. The first is a circular ring-shaped array of coupled Helmholtz resonators, modeled using a lumped parameter model. The second is an air-filled acoustic wave-tube that is modeled as a distributed acoustic-elastic coupled waveguide. The method's strengths and weaknesses are discussed from the experimentally obtained dispersion curves, and its main feature, the ability to fit the dispersion model of weak modes, is highlighted.</p
Automatic traveling wave excitation of structures with imperfect cyclic symmetry
No full textA method to generate traveling waves with maximal amplitudes in elastic structures with imperfect cyclic symmetric topology is presented. Traveling waves are useful in testing turbine-bladed disks and for the propulsion of ultrasonic motors. However, open-loop excitation of traveling waves may yield a partially standing wave due to imperfections and mode-mistuning. The present work puts forward a method that automatically locks onto the optimal excitation of the system, producing the largest possible pure propagating wave. The excitation uses autoresonance with modal filtering, and force projection control, utilizing optimum-seeking methodology. To validate the presented method, an experimental system consisting of a ring of coupled acoustic Helmholtz resonators was built. The ring was excited by the proposed method, and the ability to overcome the imperfections and automatically lock onto the optimal excitation was observed. In addition, the method was realized on a simulated, ultrasonic, acoustic levitation motor that utilizes traveling waves to control levitated objects
Active detection of small imperfections in structures with cyclic symmetry
No full textStructures possessing cyclic symmetry such as turbine bladed disks, ultrasonic motors, and toothed gear wheels can experience elevated vibration levels when small deviations from circumferential periodicity exist. Detection of these perturbations via classical system identification approaches is time-consuming, indirect, and exhibits low sensitivity to defects and are affected by measurement noise. The present work utilizes low-level forces that automatically lock onto a weighted rotating projection of the system modes at resonance frequency to enhance the detectability of small structural imperfections. The spatial localization of defects is exploited to identify multiple, localized, isolated defects' locations. The defects' severities are estimated based on the deviation from the circular structure's analytical mode shapes. Fast and enhanced precision of defect identification is obtained by employing the modal filtered Autoresonance technique. To validate the presented method, an experimental system consisting of a ring of coupled Helmholtz acoustic resonators was developed. Experimental results show good agreement with numerical simulations, verifying the method's capabilities to identify the location and severity of multiple defects. Thus, implementation of the suggested method provides fast and precise structural health monitoring of cyclic symmetric systems
Vascular Behcet and Mutations in Thrombogenic Genes: Methylene Tetrahydrofolate Reductase, Factor V, and Prothrombin
No full textVasculitis, thrombophlebitis, arterial aneurysms, and occlusions occur in about 25% of patients with Behcet's disease (BD). The common inherited gene defects, factor V (FV) 1691A (Leiden), methylene tetrahydrofolate reductase (MTHFR) 677T, and prothrombin 20210A, are known risk factors for thrombosis. The aim of the study was to evaluate the contribution of these mutations to thrombosis in Israeli patients with BD. Fifty-four patients with BD (n = 54; 27 men and 27 women) underwent clinical and genetic evaluation. Most patients (n = 43; 79.6%) were of Arab descent (31 sporadic and 12 familial cases from 4 families), and 11 patients (20.4%) were of Jewish descent (all sporadic cases). The FV Leiden mutation was identified in five patients (9.2%), and eight patients were MTHFR 677TT homozygotes (14.8%). None had the 20210A mutant prothrombin allele. No statistical differences between carriers and noncarriers with regards to demographic and disease manifestations were calculated. Arabs were diagnosed earlier than Jewish patients (25.8 +/- 11.6 compared with 37.2 +/- 10.7, p = 0.01, respectively), but Jewish patients had, respectively, more events of deep vein thrombosis (DVT) compared with Arabs (3 of 11, 27.3% and 3 of 43, 7%, p = 0.09). Thrombotic events in our patients with BD were not associated with variations in thrombophilic genes
Mordechai Gichon (Baruch Arensburg, Arie Kindler, Nili Liphschitz et Yoav Waisel) En Boqeq : Ausgrabungen in einer Oase am Toten Meer, Band 1 : Géographie und Geschichte der Oase. Das Spätrömische-Byzantinische Kastell
No full textDentzer Jean-Marie. Mordechai Gichon (Baruch Arensburg, Arie Kindler, Nili Liphschitz et Yoav Waisel) En Boqeq : Ausgrabungen in einer Oase am Toten Meer, Band 1 : Géographie und Geschichte der Oase. Das Spätrömische-Byzantinische Kastell. In: Syria. Tome 74, 1997. pp. 246-248
Mordechai Gichon (Baruch Arensburg, Arie Kindler, Nili Liphschitz et Yoav Waisel) En Boqeq : Ausgrabungen in einer Oase am Toten Meer, Band 1 : Géographie und Geschichte der Oase. Das Spätrömische-Byzantinische Kastell
No full textDentzer Jean-Marie. Mordechai Gichon (Baruch Arensburg, Arie Kindler, Nili Liphschitz et Yoav Waisel) En Boqeq : Ausgrabungen in einer Oase am Toten Meer, Band 1 : Géographie und Geschichte der Oase. Das Spätrömische-Byzantinische Kastell. In: Syria. Tome 74, 1997. pp. 246-248
Bernard Baruch papers undated, 1862-1957
No full textThe collection consists primarily of letters from Baruch on various subjects. Included are ten letters to Rudolph Kommer, author and playwright (1923-1941); a letter to Mrs. Samuel Gompers regarding her husband (1932); a letter to the editor of the Washington star regarding U.S. loans to foreign governments (1945), and two letters to Herbert Bayard Swope regarding his work on the United Nations Atomic Energy Commission (1947). Also included are seven routine letters, printer's proof for Baruch's entry in Who's Who in America, 1926-1927, three signed photographs, and addresses delivered by Baruch when awarded the Churchman's Medal, and on being awarded a gold medal by the National Institute of Social Sciences (1944). Also contains a medical certificate, signed by Simon Baruch (1840-1921), verifying that R.S. Desportes, an officer of his regiment, was unfit for duty (1862), and Baruch's declaration of intention to become a citizen of the United States
(1870)Gift, in part, of the Elsie O. and Philip D. Sang Foundatio
Reading Jeremiah with Baruch
No full textThere has been substantial discussion regarding the dependency of Baruch on Jeremiah (so Tov 1976). As part of the Jeremianic additions, Baruch has been seen merely to appropriate Jeremianic material and not provide a unique reading (so Moore 1977). This paper seeks to re-evaluate Baruch’s use and reading of Jeremiah in order to show the literary creativity of the author(s). Investigating the final form of Baruch, I argue that Baruch provides a distinctive reading of Jeremiah, one based in Second Temple Judaism, and that this reading is shaped by melding passages from Jeremiah with other books of Jewish Scripture. This is particularly seen in Baruch’s introduction and penitential prayer sections. Overall, Baruch offers a unique reading of Jeremiah that both adopts and adapts the Jeremianic text and provides a new avenue of approach for future interpretation
- …
