bluuebunny/crossref_metadata_2025_split huggingface dataset:
Active damping of vibrations in elevator cars
Authors: Hamdy A. 
Published: April 2007

AbstractThe goal of this dissertation was to develop an active vibration damping system for high‐speed elevator cars to achieve a ride comfort not reached before by passive means. The system developed comprises eight actuators, six accelerometers, eight position sensors, a signal conditioning unit, and power electronics. It is controlled by a real‐time computer utilizing a digital signal processor. A laboratory test rig was designed and constructed to allow testing the active damping system fitted to a full‐scale high‐speed elevato car. The unevennes of the two guide rails, which is the main source of vibrations, is emulated using eight hydraulic cylinders. A multivariable system identification procedure in the frequency domain was developed to obtain a linear time‐invariant system model. A first controller loop utilizes the acceleration outputs to suppress the vibrations. Due to asymmetric load distributions in the cabin, the orientation of the car with respect to the guide rails may change to the extent that for one or more actuators there may not be enough actuation distance. To correct the car orientation, a second controller loop utilizing position outputs is used. However, since the position measurements are taken between the car and the guide rails, nulling the position error signals means forcing the car to follow an average line of the two rail profiles which is the main source of vibrations. To avoid a conflict between the two loops, a frequency domain separation of the bandwidths of the two controllers is achieved. The two multivariable controllers are designed using the H∞ robust design method and employing the plant non‐inverting GS/T weighting scheme. The effectiveness of the active system was tested using rail profiles previously measured in a real building and emulated by the hydraulic excitation system. The vibration reduction factor achieved is around 5 as to a passive damping system. Meanwhile, the controller is capable of correcting the car orientation caused by asymmetric loads.
An adaptive mass damper for self‐excited oscillations
Authors: Gattulli V. , Romeo F. 
Published: April 2007

AbstractAn adaptive tuned mass damper aiming to optimally increase the critical flow velocity of transverse galloping oscillations is presented. The structure, simply modeled as an elastically supported bluff body exposed to a steady flow, has been connected to an added mass by a spring and a dashpot varying according to an adaptive control algorithm. Based on the knowledge of a reference model, describing the optimal conditions for the system, the paper presents two procedures to design a controller that allows to identify the uncertain mechanical parameters relying on a direct and an indirect approach. In the direct case, by assuring the convergency to zero of the error between the system and the reference model variables, in the indirect case, by using a wavelet based approach for on‐line system identification. The analytical developments are validated by numerical investigations on the nonlinear system in order to assess the feasibility of the proposed control system.
An intelligent fiber sensor for smart structures
Authors: Angelichio J. , Nannini M. , Farahi F. 
Published: April 2007

AbstractIn this paper we present a fiber optic sensor that is designed for embedded applications and long term health monitoring of structures. The sensor design uses an induced phase discontinuity in the fiber Bragg grating to create a narrow pass‐band within the reflection spectrum of the grating. The position of this narrow window within the Bragg spectrum is used to monitor the sensor's health. Theoretical analysis and experimental results are presented for this class of self‐monitoring sensors. Related signal demodulation scheme is also discussed.
Shaping distributed piezoelectric self‐sensing layers for static shape control of smart structures
Authors: Irschik H. , Krommer M. , Pichler U. 
Published: April 2007

AbstractIn the present paper, spatially distributed self‐sensing layers with an axially varying intensity of piezoelectric activity are studied within the context of an electromechanically coupled theory for plane flexural deformations of slender smart beams. The main purpose of our derivations is to find shape functions for a piezoelectric self‐sensing layer such that quasi‐static deflections due to known external forces can be exactly annihilated by the piezoelectric actuation. It is shown that shape functions corresponding to the bending moment distributions due to these external forces do represent solutions of this static shape control problem. In the context of self‐sensing layers, the shaped actuator can be also used as a collocated sensor, which is discussed in detail in the present paper. If the span‐wise distribution of the external forces is not known, it may be useful to design self‐sensing layers with the purpose of controlling the deflection at specific locations of the beam axis by means of shape functions with a particularly simple form. Such a concept is also presented. Furthermore, we make reference to so‐called nilpotent shape functions which are neither able to produce actuating effects nor to measure deflections of the beam. The presented theoretical findings are demonstrated for one‐span beams with various boundary conditions.
Response analysis of structures with motion‐limiters subjected to random loading
Authors: Kovaleva A. 
Published: April 2007

AbstractThe paper studies the dynamic responses of a mdf structure with a one‐side motion limiter. The system in question consists of a base ( a primary structure) impacting on a rigid limiting stop. Such a system exhibits complicated nonlinear dynamics even if the system without limiters is linear. We suppose that the effect of impacts on the motion of the base is much higher than the effect of the interaction between the base and the secondary structure. The mathematical model is thus reduced to a weakly coupled linear structure subjected to both random forces and impact loading. In this work we develop a special decomposition approach to analysis and control problems. As a result, we obtain the approximate representation of the motion of the base as a periodic motion with a slowly varying random envelope. The necessary characteristics of the motion (mean value, variance etc.) are calculated.
Seismic response of torsionally coupled structures with active control device
Authors: Date V. A. , Jangid R. S. 
Published: April 2007

AbstractA study is carried out for investigating the effectiveness of active control systems for one‐storey torsionally coupled structures. The governing equations of motion of the system are derived. The control forces are obtained using the classical linear optimal control algorithm. The stochastic seismic response of a torsionally coupled controlled system is investigated under important parametric variations such as: uncoupled lateral time period, system eccentricity and ratio of uncoupled torsional to lateral frequency of the system. In order to investigate the effectiveness of the control device, the response of the system with control device is compared with the corresponding system without control device. Further, the controlled response of the torsionally coupled system is compared with the corresponding response of the uncoupled system. It is shown that the control mechanism is also equally effective in reducing the seismic response of a torsionally coupled system. In addition, it is to be noted that the effectiveness of the active control device is overestimated when it is designed without considering the effects of torsional coupling.
Investigations on stiffness‐damping interaction for rubber bearings
Authors: Nersessyan T. , Hovhannisyan G. , Tonoyan A. , Avanesova K. 
Published: April 2007

AbstractIn this paper different types of rubber bearings are considered and their properties are described. Stiffness‐damping interconnection for each type of bearing is obtained. The investigated relationships are based both on graphs of stiffness and damping versus shear strain and on experimental hysteresis loops. Relationships between stiffness and damping allow understanding of some regular lows mentioned in the conclusions.
Linear and nonlinear models of seismoisolating foundations
Authors: Aghalovyan L. A. , Gevorgyan R. S. , Khachatryan A. M. 
Published: April 2007

AbstractRecurrent formulas are derived to determine stress tensors and displacement vectors for compressible and incompressible plate‐like foundations. A three‐layered plate with an incompressible middle layer is considered as an example of practical significance for seismostable constructions. Nonlinear problems for strip‐seismoisolators from incompressible materials are discussed.
Physico‐Chemical Characterization of Moringa concanensis Seeds and Seed Oil
Authors: Manzoor Maleeha , Anwar Farooq , Iqbal Tahira , Bhanger M. I. 
Published: April 2007

AbstractThe present work reports the characterization and comparison of Moringa concanensis seed oil from Tharparkar (a drought hit area), Pakistan. The hexane‐extracted oil content of M. concanensis seeds ranged from 37.56 to 40.06% (average 38.82%). Protein, fiber, moisture and ash contents were found to be 30.07, 6.00, 5.88 and 9.00%, respectively. The extracted oil exhibited an iodine value of 67.00; a refractive index (40 °C) of 1.4648; its density (24 °C) was 0.8660 mg mL−1; the saponification value (mg of KOH g−1 of oil) was 179.00; unsaponifiable matter 0.78%; color (1 in. cell) 1.90R + 19.00Y; and acidity (% as oleic acid) 0.34%. Tocopherols (α, γ, and δ) in the oil accounted for 72.11, 9.26 and 33.87 mg kg−1, respectively. Specific extinctions at 232 and 270 nm were 3.17 and 0.65, respectively. The peroxide and p‐anisidine values of the oil were found to be 1.75 and 1.84 meq kg−1, respectively. The induction periods (Rancimat, 20 L h−1, 120 °C) of the crude oil was 10.81 h and reduced to 8.90 h after degumming. The M.concanensis oil was found to contain high levels of oleic acid (up to 68.00%) followed by palmitic, stearic, behenic, and arachidic acids up to levels of 11.04, 3.58, 3.44 and 7.09%, respectively. The results of the present analytical study, compared with those for other Moringa species and different vegetable oils, showed M. concanensis to be a potentially valuable non‐conventional seed crop for high quality oil.
Genioglossus advancement and hyoid suspension plus uvulopalatopharyngoplasty for severe OSAHS
Authors: Yin Shan Kai , Liang Yi Hong , Ying Lu Wen , Guan Jian , Min Wu Hong , Cao Zhen Yu 
Published: April 2007

ObjectiveTo evaluate the outcome of a comprehensive surgical approach on the treatment of severe obstructive sleep apnea hypopnea syndrome (OSAHS) and find out possible predictors to the effectivenss of this approach.Study Design And SettingEighteen patients received genioglossus advancement with hyoid suspension (GAHM) and uvulopalatopharyngoplasty (UPPP). The multiple logistic regression was used to analyze predictors for the outcome of treatment.ResultsApnea hypopnea index (AHI) showed a reduction in the preoperative vs postoperative polysomnography (63.83 ± 16.34 vs 21.43 ± 20.34). With success defined as a final postoperative AHI of less than 20 events per hour, the success rate was 67%. The main differences between responders and nonresponders include age, posterior airway space (PAS), time of oxyhemoglobin saturation below 90% (CT90), and body mass index (BMI). Age and BMI were key predictors for therapeutic effect.ConclusionGAHM plus UPPP may benefit severe OSAHS patients with oropharyngeal and hypopharyngeal obstruction. The success was best predicted by low BMI and younger age.SignificanceThis paper provides reference for patient selection of UPPP plus GAHM, and considers that older or morbidly obese patients with OSAHS should be excluded from this operation.
The difference in anatomical and invasive characteristics between primary and secondary paranasal sinus mucoceles
Authors: Fu Chia‐Hsiang , Chang Kai‐Ping , Lee Ta‐Jen 
Published: April 2007

ObjectiveTo evaluate the difference in anatomical and invasive characteristics of primary and secondary paranasal sinus mucoceles.Study DesignA retrospective chart review at a tertiary academic center.ResultsDuring a 10‐year period, 57 and 109 patients with primary and secondary mucoceles were enrolled, respectively. Thirty‐five (61.4%) of primary and 26 (23.9%) of secondary mucoceles had intraorbital extension (IOE), while seven (12.3%) of primary and two (1.8%) of secondary mucoceles had intracranial extension (ICE). In comparison of tendency for IOE or ICE between primary and secondary mucoceles in each sinus, only primary maxillary mucoceles were shown to have a significantly higher probability of IOE than secondary maxillary mucoceles. Among primary mucoceles, ethmoid mucoceles had a significantly greater capability to cause IOE while maxillary mucoceles had the least. Among secondary mucoceles, frontal and ethmoid mucoceles had a greater ability to cause IOE while maxillary mucoceles had the least. As for ICE, sphenoid mucoceles had a greater potential in both groups.ConclusionsPrimary mucoceles seem to have a greater potential to cause IOE and ICE than secondary mucoceles. In both groups, ethmoid mucoceles have a higher potential of IOE, while sphenoid mucoceles have a greater tendency to cause ICE.
Accelerated radiotherapy with simultaneous integrated boost fractionation and intensity‐modulated radiotherapy for advanced head and neck cancer
Authors: Schwartz Matthew , Té Vuong , Ballivy Olivier , Parker William , Patrocinio Horacio 
Published: April 2007

ObjectiveTo determine the feasibility and toxicity profile of accelerated radiotherapy with a simultaneous integrated boost fractionation scheme with intensity‐modulated radiotherapy (SIB‐IMRT) with or without chemotherapy.Study Design And SettingForty‐nine patients with advanced head and neck cancer underwent SIB‐IMRT. Concomitant chemotherapy was administered in 29 patients.ResultsGrade 3 acute toxicities included 55% mucositis, 20% odynophagia, 12% nausea, 18% hematologic, and 8% skin. There were no grade 4 toxicities or treatment‐related deaths. With a median follow‐up of 25 months, locoregional control was 83%, and overall survival was 80%. Of patients with grade 3 late toxicities, two patients (4% of the total) required a permanent percutaneous endoscopic gastrostomy tube, and osteonecrosis occurred in one patient (2% of the total).ConclusionsSIB‐IMRT is a feasible technique that shortens the overall treatment time in the radical treatment of patients with advanced head and neck cancer while maintaining acceptable rates of acute toxicity in this study. Although the results are promising, this approach should be considered only in the setting of a clinical trial.
The implications of regulatory guidelines on allergen vial mixing for the practicing otolaryngologist
Authors: Lin Sandra Y. , Houser Steven M. , Rodriguez Hector P. 
Published: April 2007

ObjectivesTo introduce otolaryngologists to proposed standards regarding allergen vial mixing, to identify clinical implications, and to recommend efforts to address the issue of vial mixing standards.Study Design And MethodsA policy review.ResultsThe Institute of Medicine report on medical errors increased awareness of medication errors, spurring efforts to improve patient safety. One example is the United States Pharmacopoeia's (USP) Chapter 797, a standard for sterile medication compounding. This standard requires the use of a dedicated clean room, ventilation hood, air sampling, surface sampling, and formal testing of mixing personnel. Regulatory agencies may include allergy vial mixing under USP 797. Formal allergy vial mixing guidelines are presented as a standard created by the American Academy of Otolaryngic Allergy taskforce on allergen vial mixing.Conclusion/SignificanceOtolaryngologists must be involved the discussion regarding vial mixing standards to ensure that the standards developed are reasonable, safe, preserve patient access, and are based on evidence based medicine.
Videostroboscopic findings in unilateral superior laryngeal nerve paralysis and paresis
Authors: Tsai Veling , Celmer Andrew , Berke Gerald S. , Chhetri Dinesh K. 
Published: April 2007

ObjectivesOur aim was to present laryngovideostroboscopic findings in unilateral superior laryngeal nerve paresis and paralysis.Study Design And SettingRetrospective case review, academic voice clinic.MethodsBlinded retrospective review of videostroboscopic recordings from cases confirmed by laryngeal electromyography.ResultsThree cases of unilateral superior laryngeal nerve paresis and paralysis were identified. At rest, there were no common abnormal laryngeal findings. Upon phonation, common findings were ipsilateral vocal fold bowing and shortening, vocal process height asymmetry with the ipsilateral vocal process overriding the normal, and ipsilateral hyperadduction of the false vocal fold.ConclusionsThe common features noted in these cases of laryngeal electromyography‐proved uSLNp could be used to make a presumptive diagnosis of this disorder.
Black Lucques olives prevented bone loss caused by ovariectomy and talc granulomatosis in rats
Authors: Puel Caroline , Mardon Julie , Kati-coulibaly Séraphin , Davicco Marie-Jeanne , Lebecque Patrice , Obled Christiane , Rock Edmond , Horcajada Marie-Noelle , Agalias Apostolos , Skaltsounis Leandros A. , Coxam Véronique 
Published: April 2007

This study was conducted to determine whether olive fruits, rich in micronutrients, might improve bone loss in ovariectomized (OVX) rats (an experimental model of postmenopausal osteoporosis) and in OVX rats with granulomatosis inflammation (a model of senile osteoporosis). Six-month-old Wistar female rats underwent ovariectomy and were then immediately treated orally by substituting oil in the diet by 10 g/d green Lucques olives or 6 g/d black Lucques olives for each rat for 84 days. OVX rats and sham-operated controls received the same diet with oil. Three weeks before the end of the experiment, subcutaneous inflammation was provoked by injections of sterile magnesium silicate in half the animals in each group. In OVX rats, granulomatosis inflammation, characterized by a rise in inflammatory parameters such as fibrinogen, α1-acid glycoprotein, spleen weight and granulocyte level, and an impairment of oxidative status (as shown by a decrease in plasma antioxidant capacity, a higher rate of isoprostane excretion) elicited a bone loss in the whole femur and in the metaphyseal areas considered on their own. Whereas green olives had no effect on osteopenia, consumption of the black variety prevented bone loss in the whole femur and at cortical sites in those oestrogen-deficient animals with talc inflammation (diaphyseal bone mineral density: black olives and inflammation 0·2323 (se 0·0026) v. ovariectomy and inflammation 0·2117 (se 0·0030); P = 0·027). This bone-sparing effect seemed to result from an improvement in the inflammatory and oxidative status. The present data show that black olives are able to prevent bone loss in an experimental model of senile osteoporosis (oestrogen-deficient rats in which a low-grade inflammation was induced by talc injection).
Hypocholesterolaemic effects of soya proteins: results of recent studies are predictable from the Anderson meta-analysis data
Authors: Sirtori Cesare R. , Eberini Ivano , Arnoldi Anna 
Published: April 2007

In 1995, Andersonet al.published a meta-analysis, derived from most of the clinical studies on soya proteins given to individuals with varying levels of cholesterolaemia that had been reported up to that time. The meta-analysis clearly indicated that cholesterolaemias were generally reduced by diets with soya given as a partial or total substitution of animal proteins, with final mean total and LDL-cholesterol reductions of 23·2 mg/dl and 21·7 mg/dl, respectively. These findings were recently strongly criticised, based on the evaluation of later studies, frequently involving individuals with normal or moderately elevated cholesterolaemias. In the present paper, these more recent studies were re-evaluated using a ‘nomogram’ prepared on the basis of the quartiles of initial cholesterol concentrations in the Anderson meta-analysis and their corresponding CI for net cholesterol change. The five studies belonging to the first quartile and thirteen out of the fourteen belonging to the second quartile gave results perfectly in line with the nomogram. Out of the fourteen studies belonging to the third quartile, ten agreed with the nomogram and two gave lower cholesterol reductions, whereas two gave higher reductions. Unfortunately, none of the recent studies belonged to the fourth quartile as treatment with statins or other lipid-lowering drugs is now mandatory in the presence of very high cholesterol levels. The re-evaluation thus shows that the thirty-three studies published in the past 10 years are in agreement with the Anderson meta-analysis and confirm its validity.
Habitat use and phenology of the large insular endemic grasshopperAcrostira euphorbiae(Orthoptera: Pamphagidae)
Authors: López H. , Nogales M. , Morales E. , Oromí P. 
Published: April 2007

AbstractThe habitat use and the phenology of the large grasshopperAcrostira euphorbiaeGarcía & Oromí endemic to La Palma (Canary Islands) are studied. This grasshopper is entirely dependent on the Canarian endemic shrubEuphorbia lamarckiiboth for food and to avoid predation. Adults stay on subapical branches during the day, probably to reduce the risk of predation, and climb up to the apex at night to feed. While females seem to ensure the genetic diversity of offspring by waiting for visits by different males, the latter have to move to guarantee their reproductive success. Monophagy in this species may be related to the year-round presence of tender shoots, and to the predator-repellent toxic latex found in the host plant. Unlike related species from continental areas, adults and nymphs ofA. euphorbiaeare present almost all year round, probably in adaptation to the particular climate of the islands. Nymphs are more abundant in winter, whenEuphorbialeaves are most available. However, adults are more abundant than nymphs in spring, summer and autumn. Males develop more quickly than females, an apparent reproductive strategy based on achieving sexual maturity to coincide with females undergoing imaginal moulting. Matings start immediately after adult females emerge. Densities oscillated between 73 and 193 individuals ha−1, which can be considered a low value compared with other continental pamphagid species.