Length Of Poly Research Articles

A comparative work on vibration control of a quarter car suspension system with two different magneto-rheological dampers

This work compares the ride comfort of a passenger vehicle whose suspension system is equipped with two different magneto-rheological (MR) dampers: with and without bypass holes in the piston. In order to achieve this goal, two cylindrical type MR dampers, which otherwise have the same such geometrical dimensions as radius of piston, length of pole and distance between two poles, are designed based on a mathematical model and subsequently manufactured. One of MR dampers is then modified by making bypass holes in the piston bobbin structure to obtain a relatively low slope of damping force in the pre-yield region. The field-dependent damping force characteristics are investigated through both simulation and experiment. After characterizing the field-dependent damping force of the two MR dampers, a quarter car model is established to evaluate the ride comfort. In this work, a simple but very effective sky-hook controller is adopted, and vibration control performance is evaluated under two road profiles: bump and random road excitations. It is demonstrated through simulation and experiment that the MR damper with bypass holes provides better ride comfort to the car so equipped than that without.

Strategies for Improving Voltage Waveform of an Outer Rotor PMSG: No-Load Prototype Testing

This paper deals with the design and no load test of an outer rotor Permanent Magnet Synchronous Generator (PMSG). For this purpose, many analyses were made to identify which modification of the geometrical parameters help us to improve the voltage waveform in winding terminals of the generator. Tests results complements previous works where were presented analysis of this 5 kW PMSG. The Total Harmonic Distortion (THD) is analyzed, under design parameters handling, i.e., the geometry of the stator, the polar arc percentage, the air gap, the skew angle in rotor poles, the pole length and the core steel class. Seventy-six cases are simulated and the results provide useful information for designing these machines. Tests on machine help us to verify the electromagnetic analysis. Finally, some important stages of the generator building process are shown.

Effect of the variation of the gating system on the magnetic properties of injection molded pole-oriented rings

Abstract The demand for contactless and wear-free sensor systems for the measurement of different physical values, such as angle, position, or speed has increased over the past years and opened up new application areas for magnetically sensitive sensors. Polymer bonded magnets can be used as signal transmitters in these sensor applications. In general, a high precision and good repeatability of the magnetic field is required, whereas in particular, a high peak flux density and accurate pole length of each pole is demanded for precise measurement. These polymer bonded magnets can be produced economically using the injection molding process with an integrated magnetization of the particles, such that a second magnetization step is unnecessary. This article addresses the influences of the gating system on the magnetic properties of multipolar bonded rings. Further, the particle orientation as well as filler content at different locations, and along the pathway are investigated. It was evaluated that the gating system significantly influences the pole length accuracy, as well as the peak flux density. However, differences in the filler orientation and content cannot be analyzed quantitatively.

A test of fixed and moving reference point control in posture

This study investigated two contrasting assumptions of the regulation of posture: namely, fixed and moving reference point control. These assumptions were tested in terms of time-dependent structure and data distribution properties when stability is manipulated. Fifteen male participants performed a tightrope simulated balance task that is, maintaining a tandem stance while holding a pole. Pole length (and mass) and the standing support surface (fixed surface/balance board) were manipulated so as to mechanically change the balance stability. The mean and standard deviation (SD) of COP length were reduced with pole length increment but only in the balance board surface condition. Also, the SampEn was lower with greater pole length for the balance board but not the fixed surface. More than one peak was present in the distribution of COP in the majority of trials. Collectively, the findings provide evidence for a moving reference point in the maintenance of postural stability for quiet standing.

Correlation between chromosomal distribution and embryonic findings on ultrasound in early pregnancy loss after IVF-embryo transfer.

Do early pregnancy losses (EPLs) with and without embryos differ in chromosomal distributions? The chromosomal abnormality rate is significantly higher in miscarriages with embryos than without after in vitro fertilization (IVF)-embryo transfer. Chromosomal abnormalities are the main causes of EPLs, the rate of which is up to 24-30% in the IVF population. Little research has been conducted on the correlations between the chromosomal distributions of EPL and the existence of an embryo or with the postmortem embryonic pole length, and the existing results have been inconsistent. The data of 2172 women who underwent dilation and curettage (D&C) from January 2008 to December 2013 for missed abortion were analyzed retrospectively. The existence of an embryonic pole and the length of the postmortem embryonic pole of the EPL were evaluated by transvaginal sonography (TVS). Ultrasound findings were compared with karyotype results. This analysis included 2172 infertility patients who had singleton pregnancies and experienced EPLs after IVF-embryo transfer. The EPLs were divided into embryonic and anembryonic groups based on TVS diagnosis. The crown-rump length of the fetal pole (observed once) was measured twice for each fetus after confirmation of fetal death, subject to the final measurement before D&C. The karyotype analysis was performed using comparative genomic hybridization (CGH) plus fluorescence in situ hybridization technology. The chromosomal abnormality rate was significantly higher in male miscarriages with an embryo than in those without an embryo (54.14% versus 37.50%, P ≤0.001). In the anembryonic group, the abnormal karyotype rate was significantly higher in the yolk sac only than that in the empty sac group (46.11% versus 29.77%, P=0.001); in the embryonic group, the abnormal karyotype rate in miscarriages with postmortem embryonic pole length >20 mm was significantly lower than that in miscarriages with pole length <10 mm (P=0.006) and 10-20 mm (P=0.036). There were significant differences in abnormal karyotype rates among miscarriages of different developmental stages (P≤0.001). The cases with embryonic stages had the highest risk (54.89%) of an abnormal karyotype and those with fetal stages had the lowest risk (18.18%). There were significant differences in the length of postmortem embryonic poles among groups with different karyotypes (P≤0.001). In addition, trisomy 21, monosomy X and triploidy had the longest lengths of postmortem embryonic poles (16, 15.3 and 11.6 mm, respectively). Although the efficacy of a non-parametric test is less than that of a parametric test, non-parametric testing was used to compare the embryonic pole lengths in this study, owing to the non-normal distribution and non-homogeneous variances caused by limited cases of some rare chromosomal abnormalities. Another limitation was that CGH was unable to detect mosaicism. Furthermore, the results were not compared with a non-IVF population. Finally, maternal cell contamination is a major problem in studying miscarriage tissue, even using molecular techniques. Although TVS findings clearly cannot replace karyotype information, our results are important because they call attention to the fact that EPLs that occur after implantation but prior to embryo formation frequently have normal karyotypes. This finding might direct future research towards studies of DNA sequences, or of epigenetic correlations with pregnancy failure. This study was funded by the Scientific Research Foundation of Reproductive and Genetic Hospital of Citic-Xiangya. The authors have declared that no conflicts of interest exist. N/A.

The Influence of Pole Length on Performance, O2 Cost, and Kinematics in Double Poling.

In the double-poling (DP) cross-country-skiing technique, propulsive forces are transferred solely through the poles. The aim of the current study was to investigate how pole length influences DP performance, O2 cost, and kinematics during treadmill roller skiing. Nine male competitive cross-country skiers (24 ± 3 y, 180 ± 5 cm, 72 ± 5 kg, VO2max running 76 ± 6 mL · kg-1 · min-1) completed 2 identical test protocols using self-selected (84% ± 1% of body height) and long poles (self-selected + 7.5 cm; 88% ± 1% of body height) in a counterbalanced fashion. Each test protocol included a 5-min warm-up (2.5 m/s; 2.5°) and three 5-min submaximal sessions (3.0, 3.5, and 4.0 m/s; 2.5°) for assessment of O2 cost, followed by a selfpaced 1000-m time trial (~3 min, >5.0 m/s; 2.5°). Temporal patterns and kinematics were assessed using accelerometers and 2D video. Long poles reduced 1000-m time (mean ± 90% confidence interval; -1.0% ± 0.7%, P = .054) and submaximal O2 cost (-2.7% ± 1.0%, P = .002) compared with self-selected poles. The center-of-mass (CoM) vertical range of displacement tended to be smaller for long than for self-selected poles (23.3 ± 3.0 vs 24.3 ± 3.0 cm, P = .07). Cycle and reposition time did not differ between pole lengths at any speeds tested, whereas poling time tended to be shorter for self-selected than for long poles at the lower speeds (≤3.5 m/s, P ≤ .10) but not at the higher speeds (≥4.0 m/s, P ≥ .23). DP 1000-m time, submaximal O2 cost, and CoM vertical range of displacement were reduced in competitive cross-country skiers using poles 7.5 cm longer than self-selected ones.

Analysis of Lower Breast Pole Length and Nipple-Areola Complex Position Following Superior Pedicle, Short Horizontal Scar Breast Reduction.

Postoperative changes following superior pedicle breast reduction are closely related to the pattern of skin resection. We have observed that the superior pedicle, short horizontal scar breast reduction technique provides a stable breast shape in the long term. We test the validity of our clinical observations through objective analysis of postoperative dimensional changes following superior pedicle, short horizontal scar breast reduction. Of 42 patients who underwent superior pedicle, short horizontal scar breast reductions between January 2011 and June 2012, 38 (75 breasts) were available for long-term follow-up. The midclavicular point-to-superior areolar border distance (A), the inferior areolar border-to-inframammary fold (IMF) distance (B), and the areolar diameter (C) were measured and recorded at the time of (1) preoperative markings, (2) first postoperative visit, and (3) 2-year postoperative follow-up visit. The specifications of the preoperative markings were recorded to analyze their correlation with actual breast dimensions. The superior border of the nipple-areola complex (NAC) was located, on average, 1.2cm higher at the first postoperative visit when compared with the markings (P<0.001). The nipple-areola position did not change significantly in the long term (P=0.224). The average postoperative increase in the IMF-to-inferior areolar border distance between the first postoperative visit and the long-term follow-up visit was 0.3cm (P<0.001). Although statistically significant, this extent of change (4.5%) in the lower pole vertical length was clinically unidentifiable, and pseudoptosis did not occur after superior pedicle, short horizontal scar mammaplasty. Long-term stability of the NAC position and lower breast pole length makes superior pedicle, short horizontal scar breast reduction a predictable and dependable option for primary breast reduction/mastopexy and for a matching procedure. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Influences on the Magnetic Properties of Injection Molded Multipolar Rings

Abstract Polymer bonded magnets with a multipolar structure can be economically produced using the injection molding process for applications such as electric drives or sensor modules. Depending on the specific application, certain requirements of the multipolar bonded magnets, such as a high peak flux density or accurate pole length of each pole, must be assured. The multipolar magnetic structure of the parts can be applied during the injection molding process by incorporating a magnetic field inside the mold. Thus, the hard magnetic particles are oriented and magnetized directly in the injection molding process. The final properties of the multipolar molded magnets are affected by different parameters, such as the magnetic compound, the mold design and the processing parameters. This paper addresses the effects processing parameters have during the injection molding process. Additionally, the role the filler volume content plays with the properties of pole-oriented molded multipolar rings is also investigated. In particular, the magnetic characteristics, such as the maximum radial flux density, the pole length and the rate of the course of the flux density, were investigated. Further, the orientation of the particles and the influence of the varied parameters on the geometry of the rings were analyzed. It was found that the varied parameters do not significantly influence the accuracy of the pole length. The slope of the flux density curve is influenced by the peak maxima and varies slightly due to the high peak flux densities.

Development of a Desktop-Type Superconducting Bulk Magnet

We developed a desktop-type superconducting bulk magnet using a Stirling cryocooler with the aim of miniaturizing the system. This refrigerator was compact and highly energy efficient because a compressor was not needed outside; power consumption was approximately 160 W. Moreover, the length of the magnetic pole was decreased by restricting the activation method to pulsed field magnetization. A GdBCO bulk material 45 mm in diameter and 20 mm thick was attached to the cold stage of a refrigerator and was covered with a vacuum chamber. The sample was cooled from room temperature to 52.3 K in approximately 4.5 h. When a single pulsed field was applied in amplitudes varying from 0.8 to 7.0 T, the maximum trapped field was approximately 2.8 T at the center of the bulk surface in the applied field of 7.0 T. Moreover, the maximum magnetic field on the chamber's surface was approximately 1.3 T, and the total magnetic flux was 0.94 mWb. The operational status after magnetization was good, and the operating sound was small.

Shuffled Frog Leaping Algorithm for Multi-objective Design Optimization of Transverse Flux Linear Motor

This article presents a multi-objective design optimization of the transverse flux linear motor with an inner mover using the shuffled frog leaping algorithm. The optimization target is to reduce the transverse flux linear motor weight while maximizing its thrust force as well as minimizing its detent force. The design variables of the optimization problem are the stator pole length, air-gap length, winding window width, and stator pole width, where these variables affect the motor characteristics. The response surface methodology was used to obtain a mathematical model of the motor weight, detent force, and thrust force in terms of the design variables. Finite-element computations were used for numerical experiments on the geometrical design variables to determine the coefficients of a second-order analytical model for the response surface methodology. The finite-element analysis model is verified with the experimental results of a scaled-down model of the transverse flux linear motor. The effectiveness of the shuffled frog leaping algorithm model is compared with that of the genetic algorithm model and particle swarm optimization model. With the proposed shuffled frog leaping algorithm technique, the weight of the initially designed transverse flux linear motor and its detent force is reduced and its thrust force is increased.

A novel decoupled parallel mechanism with two translational and one rotational degree of freedom and its performance indices analysis

Less degrees of freedom parallel mechanism is widely used in many fields with its unique advantages. A decoupled parallel mechanism with 2 degree-of-freedom translation and 1 degree-of-freedom rotation is presented, and its performance evaluation indices analysis is performed. By the constraint screw method, the motion feature of the mechanism and its number of degree of freedom are analyzed. The constrained equations of the mechanism are established according to the constrained conditions of the pole length. The analytical expression of the forward and inverse position for the mechanism is deduced, and the expression of the Jacobian matrix is derived, which validated the decoupling feature of the mechanism. The singularity of the mechanism is also carried out. The performance evaluation indices for the decoupled parallel mechanism are discussed and the corresponding performance indices analysis of the proposed decoupled parallel mechanism is executed. The novel decoupled parallel mechanism presented herein enriches the parallel mechanism structure, and the definition and analysis of the performance evaluation indices should be meaningful for the further design and optimization of the decoupled parallel mechanism.

Numerical study of magnetic circuit response in magneto-rheological damper

Purpose – The purpose of this paper is to evaluate the performance of the semi-active fluid damper. It is recognized that the performance of such a damper depends upon the magnetic and hydraulic circuit design. These dampers are generally used to control the vibrations in various applications in machine tools and robots. The present paper deals with the design of magneto-rheological (MR) damper. A finite element model is built to analyze and understand the performance of a 2D axi-symmetric MR damper. Various configurations of damper with modified piston ends are investigated. The input current to the coil and the piston velocity are varied to evaluate the resulting change in magnetic flux density (B), magnetic field (H), field dependent yield stress and magnetic force vectors. The simulation results of the various configurations of damper show that higher magnetic force is associated with plain piston ends. The performance of filleted piston ends is superior to that of other configurations for the same magnitude of coil current and piston velocity. Design/methodology/approach – The damper design is done based on the fact that mechanical energy required for yielding of MR fluid increases with increase in applied magnetic field intensity. In the presence of magnetic field, the MR fluid follows Bingham’s plastic flow model, given by the equation τ = η γ•+τ y (H) τ &gt; τ y . The above equation is used to design a device which works on the basis of MR fluid. The total pressure drop in the damper is evaluated by summing the viscous component and yield stress component which is approximated as ΔP = 12ηQL/g3W + CτyL/g, where the value of the parameter, C ranges from a minimum of 2 (for ΔPτ ΔPη less than approximately 1) to a maximum of 3 (for ΔPτ/ΔPη greater than approximately 100). To calculate the change in pressure on either side of the piston within the cylinder, yield stress is required which is obtained from the graph of yield stress vs magnetic field intensity provided by Lord Corporation for MR fluid −132 DG. Findings – In this work, three different finite element models of MR damper piston are analyzed. The regression equations, contour plots and surface plots are obtained for different parameters. This study can be used as a reference for selecting the parameters for meeting different requirements. It is observed from the simulation of these models that the plain ends model gave optimum magnetic force and 2D flux lines with respect to damper input current. This is due to the fact that the plain ends model has more area when compared with that of other models. It is also observed that filleted ends model gave optimum magnetic flux density and yield stress. As there is reduced pole length in the filleted ends model, the MR fluid occupies vacant area, and hence results in increased flux density and yield shear stress. The filleted ends assist the formation of dense magnetic flux lines thereby increasing the flux density and yield stress. This implies that higher load can be carried by the filleted ends damper even with a smaller size. Originality/value – This work is carried out to manufacture different capacities of the dampers. This can be applied as vibration controls.

Double-Poling Biomechanics of Elite Cross-country Skiers: Flat versus Uphill Terrain.

In light of the recent revolutionary change in the use of the double-poling (DP) technique in cross-country skiing, our purpose was to compare the associated kinetics and kinematics on flat (DPflat) and uphill terrain (DPup), as well as to identify factors that determine performance. Thirteen elite male cross-country skiers completed two incremental speed tests (Vpeak) involving roller skiing with the DP technique at moderate (13 and 24 km·h) and high speed (15 and 28.5 km·h) on a treadmill that was flat (1°) or tilted uphill (7°). Pole forces and three-dimensional whole-body kinematics were monitored simultaneously. In comparison to DPflat, during DPup, swing times were much shorter (-48%) and peak pole forces greater (+13%) and generated later during the poling phase (+68%), with higher impulses for all force components (+87%-123%). Furthermore, pole forces were 18% more effectively oriented for propulsion. During DPup, the skiers demonstrated more flexed elbows, as well as shoulder angles that were less flexed in the forward direction and less abducted throughout the poling phase, together with more highly flexed knee and ankle joints, a more upright thorax, less flexed hips, and a shortened backward swing after pole off. With DPup, the skiers raised their center of mass 25% more, attaining maximal heel raise and maximal vertical position at a timepoint closer to pole plant compared with flat. On the uphill incline, the magnitude of Vpeak was positively related to body mass, relative pole length (% body height), and magnitude of heel raise. The present findings provide novel insights into the coordination, kinetics and kinematics of elite skiers while DP on flat and uphill terrain.

Evaluation of optimization algorithms for the design of a magnetic cell separator for malaria-infected blood

Recently, a dialysis-like filtration device has been devised to remove the red blood cells infected with the malaria parasite from whole blood using magnetic separation techniques. The capturing efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, channel height, length and flow rate. In this study, these parameters are varied in several common optimization algorithms, so as to minimize the channel length while maximizing the capturing efficiency. The equations of motion are solved numerically to predict the trajectories of the infected cells within an idealized rectangular micro-channel incorporating periodic high gradient magnetic poles. The channel length of the optimized design is obtained, together with the associated capturing efficiency. The optimization of the channel geometry and flow rate improves the efficiency of the device.

The pendulum-slosh problem: Simulation using a time-dependent conformal mapping

Suspending a rectangular vessel which is partially filled with fluid from a single rigid pivoting pole produces an interesting theoretical model with which to investigate the dynamic coupling between fluid motion and vessel rotation. The exact equations for this coupled system are derived with the fluid motion governed by the Euler equations relative to the moving frame of the vessel, and the vessel motion governed by a modified forced pendulum equation. The nonlinear equations of motion for the fluid are solved numerically via a time-dependent conformal mapping, which maps the physical domain to a rectangle in the computational domain with a time dependent conformal modulus. The numerical scheme expresses the implicit free-surface boundary conditions as two explicit partial differential equations which are then solved via a pseudo-spectral method in space. The coupled system is integrated in time with a fourth-order Runge–Kutta method. The starting point for the simulations is the linear neutral stability contour discovered by Turner et al. (2015, Journal of Fluid & Structures 52, 166–180). Near the contour the nonlinear results confirm the instability boundary, and far from the neutral curve (parameterized by longer pole lengths) nonlinearity is found to significantly alter the vessel response. Results are also presented for an initial condition given by a superposition of two sloshing modes with approximately the same frequency from the linear characteristic equation. In this case the fluid initial conditions generate large nonlinear vessel motions, which may have implications for systems designed to oscillate in a confined space or on the slosh-induced-rolling of a ship.

Experimental study on ablation zone and characteristics of microwave ablation in porcine kidney in vitro

To observe the ablation zone and characteristics of microwave ablation with different power and time in the model of porcine kidneys in vitro. 2 450 MHz water circulative-cooling microwave needles were used, and the length of the anterior pole was 1.10 cm. The independent variables were power (50-70 W), time (240-600 s) and ablated with different combinations. The ablation shape, zone and pathological characteristics were observed. The effective ablation shape was similar to a chestnut and the ablation zone enlarged with the increasing of power and time. When combined with 50 W/480 s, 60 W/300 s, 70 W/240 s, the largest transverse-diameter of the ablated tissue was close to 3.00 cm and the length-diameter was about 3.30 cm. The pathological characteristics indicated that renal tissues of carbonization zone were thoroughly necrotic.Coagulative necrosis was observed in coagulation area, though there were residual profile of glomerulus, renal tubular and vessels, they had lost activity. Most of the tissues in transition zone were normal, however, some cells were swelling because of thermal damage. Microwave ablation is an emerging thermal therapy which can be safely, effectively used in the treatment of renal tumors that are smaller than 3 cm.

Distance, Asymmetric Information, and Mortgage Securitization

Do lemon problems distort trade on secondary mortgage markets? In this paper, I present new evidence that they do. Using the geographic distance between lenders and borrowers as a proxy for the absence of private bank information, I document a systematic positive link between distance and the mortgage sale rate. Mortgage securitization encourages lending at a ten-foot pole's length, signaling that the originating lender has no private information about the borrower. I show that this effect is stronger for borrowers about whom the lender has greater incentives to acquire information, including low-income (versus high-income) borrowers and loans originated just above the conforming loan-limit (in the illiquid jumbo market where the GSEs are barred from purchasing mortgages). Moreover, I show that mortgage sale rates dropped following the removal of barriers to physical bank entry in the 1990s. The welfare implications are ambiguous: mortgage securitization facilitates credit supply in “unbanked” areas without a local, physical bank presence, but disincentivizes bank information production about loan applicants.

Magnetic field design of 30 cm diameter ion thruster

In order to make reasonable proposals on the magnetic design of 30 cm diameter ion thruster, the effects of magnet diameter and the spacing on the magnet strength and the confinement length of the discharge electron have been studied. By utilizing Maxwell-3D software, the magnetic field distribution was obtained with the permanent magnet on the cylindrical section oriented at 30, 60 and 90 to that on the conical section. According to different field calculated, several discharge parameters, such as electron temperature, ion density and ionization efficiency were calculated. The results indicate that when discharge voltage of 30 V，magnet pole length of 0.008 m and magnet spacing of 0.12 m are set, the confinement length of the primary is in the order of 50 m. When the angles between the permanent magnet on the cylindrical section and that on the conical section are 30, 60 and 90, the magnetic field contour inside the discharge chamber is in the range of 0.002-0.005 T. With the angle being 60, the magnetic field and filed free region are more reasonable compared to the cases of 30 and 90, when the electron temperature is about 2-6 eV, the plasma density is about (4-8)1017/m3and the collisional frequency rate of electron is in the range of 0.2-1.8.

Long-term changes in nipple-areolar complex position and inferior pole length in superomedial pedicle inverted 't' scar reduction mammaplasty.

Proper nipple-areolar complex position in reduction mammoplasty patients is a challenging problem regardless of the preferred technique. Postoperatively, the nipple-areolar complex is often not located at the most projected area of the breast. This retrospective observational study aimed to find the long-term measurements of the nipple-areolar complex position and inferior pole length after inverted T scar-superomedial pedicle reduction mammoplasty. Forty-eight female patients (96 breasts) were included in this study. The inclusion criteria were that no previous operation should have been done on any of the breasts and both NAC complexes should be at least 30 cm from the midclavicular point. Preoperatively, the distance from the midclavicular point to the new nipple was recorded. All patients were operated on with the inverted T pattern and superomedial pedicle technique. The resection weights, the distance from the midclavicular point to the nipple distance, and the distance from the NAC lower border to the inframammary fold were evaluated postoperatively with an average of 15-month follow-up. The mean preoperative distance from the midclavicular point to the nipple was 34.21 cm for the right breast and 34.26 cm for the left breast. The mean resection weight per breast was 1035 g for the right breast and 1081 g for the left breast. The descent of the NAC was 1.61 cm for the right breast and 1.79 cm for left breast (mean: 1.7 cm) at the end of the follow-up. Additionally, the inframammary length increased 3.31 cm for the right breast and 3.59 cm for the left breast (mean: 3.45 cm). In this study, we found that the new nipple-areolar complex does not go upward but goes downward. However, it was not located at the most projected area of the breast as it was set intra-operatively. This was because the lower pole of the breast sagged more than the nipple: clinically, we observed a nipple superior displacement of 1.75 cm (3.45 - 1.7 = 1.75). According to this calculation, we believe that the new nipple position should be marked at 1.5-1.75 cm below the most projected area of the breast after final shaping so that in the long term, the nipple-areolar complex would be at the proper position. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Optimal Design of Magnetorheological Fluid Damper Based on Response Surface Method

A B S T R A C T In this research, the effect of shape parameters such as number of magnet wire turns, spools, thickness of the gap, and pole length in a Magnetorheological (MR) fluid damper is analytically investigated and the optimization of these parameters is done with response surface method (RSM) which is combined Neuro-Fuzzy method and Particle Swarm Optimization (PSO) algorithm. Since the electromagnetic and mechanical components of a Magnetorheological (MR) fluid damper have a direct effect on the electrical power consumption, time delay, and damped force that are considered as objective functions. Because of the nonlinear behavior of the components, a robust approach is needed to predict their reactions; therefore, Neuro-Fuzzy is utilized to generate a high accurate surface and PSO finds the optimum solution base on the surface. The sensitive analysis is also performed to examine the variation of the objective functions with various input parameters. In this process, the best parameters are obtained by overtaking the appropriate value of the objective functions. The results demonstrate that the optimum MR damper has provided the best configurations, so that damps a maximum force in minimum time and lowest power consumption. On the other hand, the amplitude of vibrations is significantly decreased in the presence of the optimized MR damper. doi: 10.5829/idosi.ije.2015.28.09c.14