Motional Resistance Research Articles

Development of an occupant multi-body model based on Japanese male characteristics data for rear impact analysis

A human multi-body model was developed to quickly analyse vehicle occupant responses during rear collision. The outer body geometry of the human model was obtained from scan data of a Japanese male. Data were divided into 17 rigid body segments. The centre of gravity, mass and moment of inertia of each segment was determined by regression. Sixteen articulations were modelled with revolute joints. Characteristics of each joint were defined according to data of passive joint resistance and range of motion for Japanese men. The model was then validated against results of reported Japanese volunteer rear impact tests. Simulation and experimental results agreed well in terms of the rotational angle of the head and neck and the horizontal displacement of the first thoracic vertebra (T1). Hence, a reasonable occupant model can be developed by appropriately combining published data of human characteristics.

Dual-Mode AlN-on-Silicon Micromechanical Resonators for Temperature Sensing

In this paper, we present dual-mode (DM) AlN-on-silicon micromechanical resonators for self-temperature sensing. In-plane width-shear (WS) and width-extensional (WE) modes of [110]-oriented silicon resonators have been used as alternatives to first- and third-order modes to enhance DM temperature sensitivity by engineering device geometry, which reduces inherent beat frequency f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> between the two modes. This configuration provides a 50× improvement in temperature coefficient of beat frequency (TCf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> ) compared with single-mode temperature measurement and eliminates the need for additional frequency multipliers to generate f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> from its constituents. [100]-oriented WS/WE resonators provide 4× larger TCF difference between modes (ΔTCF) than first and third width-extensional resonators, which further contributes to TCf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> enhancement. WS/WE mode resonators also demonstrate the capability of operating as a temperature-stable reference f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> . The proposed modes for DM operation have high Q and low motional resistance, and are 180 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> out-of-phase when operated in two-port configuration, thus enabling mode-selective low-power oscillator interfacing for resonant temperature sensing.

A comparative trend in forecasting ability of artificial neural networks and regressive support vector machine methodologies for energy dissipation modeling of off-road vehicles

Machine dynamics and soil elastic–plastic characteristic sort out the soil-wheel interaction productions as very complex problem to be estimated. Energy dissipation due to motion resistance, as the most prominent performance index of towed wheels, is associated with soil properties and tire parameters. The objective of this study was to develop, for the first time, a model for prediction of energy loss in soil working machines using the datasets obtained from soil bin facility and a single-wheel tester. A total of 90 data points were derived from experimentations at five levels of wheel load (1, 2, 3, 4, and 5 kN), six tire inflation pressure (50, 100, 150, 200, 250, and 300 kPa) and three forward velocities (0.7, 1.4 and 2 m/s). ANN (Artificial neural network) was used for modeling of obtained results compared to the forecasting ability of SVR (support vector regression) technique. Several statistical criterions, (i.e. MAPE (mean absolute percentage error), MSE (mean square error), MRE (mean relative error) and coefficient of determination (R2) were incorporated in the investigations. It was observed, on the basis of statistical criterions, that SVR-based generalized model outperformed ANN in modeling energy loss and exhibited its applicability as a promising tool in this domain.

Real-time monitoring of cell mechanical changes induced by endothelial cell activation and their subsequent binding with leukemic cell lines

Endothelial cell (EC) activation and their subsequent binding with different cells have various mechanical consequences that, if monitored real time, can serve as a functional biomarker of many pathophysiological response mechanisms. This work presents an innovative and facile strategy to conduct such monitoring using quartz crystal microbalance (QCM), thereby relating the shifts in its frequency and motional resistance to morphological changes upon cell–cell and cell–substrate interactions. By activating ECs with TNF-α and then characterizing their binding with HL-60 and KG-1 leukemia cells, we are able to induce the mechanical changes in ECs especially in the region of cell–substrate contact which resulted in dynamically coupled mass and viscoelastic changes representing the extent of both activation and binding. The activated ECs suffered a decrease of cellular contact area, leading to positive frequency shift and decreased motional resistance. The binding of leukemia cells onto pre-activated ECs exerted a mechanical force to regain the cell surface contact which resulted in the obvious QCM responses opposite to that of activation, and proportional to the number of cells added, in spite of the fact that these added cells are extremely outside the extinction boundary of the shear wave generated by QCM. Different cell lines demonstrate different attachment behavior, which was detected by the QCM. Despite these variations are quite subtle, yet the sensitivity of the technique for dynamic changes at the interface makes them detectable. Moreover, the reproducibility of the generated data determined at each step by deviation measurements (<10%) in response plot was very high despite the high possible heterogeneity in cell populations. The results are explained on the basis of simple theoretical and physical models, although, the development of a more quantitative and precise model is underway in our laboratory.

A capacitive silicon resonator with a movable electrode structure for gap width reduction

This paper presents a capacitive silicon resonator with movable electrode structures to reduce the motional resistance for lower insertion loss and lower phase noise, and also increase the tuning frequency range for the compensation of temperature drift of the silicon oscillator. The resonant frequency of the fabricated device with a length of 500 µm, width of 440 µm and thickness of 5 µm is observed at 9.65 MHz, and the quality factor is 49 000. Using an electrostatically drived movable electrode structure, it is shown that the motional resistance is reduced by 200 times, the output signal (insertion loss) is increased by 21 dB and the tuning characteristic of the frequency is also increased by seven times over that of the structures without movable electrodes.

Effect of grip type, wrist motion, and resistance level on pressures within the carpal tunnel of normal wrists

Elevated carpal tunnel pressure (CTP) has been associated with carpal tunnel syndrome. This study systematically evaluated the effect of wrist motion resistance and grip type on CTP during wrist motion typical of occupational tasks. CTP during four wrist motion patterns, with and without resistance, and with and without gripping, was measured in vivo in 14 healthy individuals. CTP measured during compound motions fell between that measured in the cardinal planes of wrist flexion/extension and radial/ulnar deviation. Generally, with no active gripping there was little pressure change due to wrist angular displacement or resistance level. However, concurrent active pinch or power grip increased CTP particularly in motions including extension. CTP typically did not increase during wrist flexion, and in fact often decreased. Extension motions against resistance when employing a pinch or power grip increase CTP more than motions with flexion. Results could help inform design or modification of wrist motion intensive occupational tasks. © 2014 The Authors. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

High Temperature Tensile Properties and Its Mechanism in Low-Carbon Nb-Bearing Steels

The aim of this study is to clarify the high-temperature strengthening mechanism of Nb-bearing ultra-low carbon steel, which is wellknown as superior steel for high-temperature applications. Observations by Three-dimensional Atom Probe (3DAP) suggested that the Nb atoms are either distributed in a solid solution within the grain or segregated at the grain boundary after hot-rolling. The strength at 600°C increases significantly upon addition of Nb, and the corresponding dominant strengthening mechanism is considered to consist of the following: the resistance for the dislocation gliding motion due to solute Nb, the retardation of the dislocation climbing-up motion due to solute Nb and Nb­C dipoles, and the resistance of the dislocation motion caused by the Nb­C(N) clusters formed when the materials are heated up to 600°C within 10s and then held for 600s. Further, compared with Nb-free steel or 0.1% Nb-bearing steel, 0.3% Nb-bearing steel has considerably reduced ductility at 600°C. This is attributed to the retardation of recovery due to the Nb addition. TEM observations imply that the dynamic recovery takes place easily during the tensile deformation at 600°C in Nb-free steel or 0.1% Nb-bearing steel, whereas the tensile stress increases significantly because of the work hardening presumably caused by the retardation of the restoration process by further addition of Nb. Hence, a rupture followed by necking is thought to occur easily. Moreover, there is a possibility that the segregated Nb at the ferrite grain boundary might affect the dislocation behavior resulting in an increase in the steel strength at a high temperature and a retardation of the recovery process. This possibility will be investigated in a future work. [doi:10.2320/matertrans.M2013393]

The Analysis of Motion Dynamics and Resistance of the Multipurpose Boat Operating in Shallow Water

Polish market of small boats has been developed very dynamically in recent years. Market competition forces the shipyards to build new more efficient hull forms and to cut the cost of production as well. This is why modern computer simulation programs are used more often by naval architects. Another trend is to design more universal ships that may be used by larger number of diversified customers. This paper presents project proposal of multipurpose boat hull form. The boat was design to fulfill the requirements imposed by public services like water police, fire brigades, and border guards. It is supposed to be operated on unexplored floodplains and other type shallow waters. The analysis of boat’s motion was based on computer simulations. The resistance curve was evaluated with two methods: comparison study of model test results of similar ships and CFD methods. The results obtained from Ansys Fluent and FINE/Marine systems were compared in this paper. It was shown that taking into consideration dynamic trim and sinkage has a significant impact on free surface capture and resistance values.

Surface electromyographic recordings after passive and active motion along the posterior myofascial kinematic chain in healthy male subjects

To map the association of muscle activations along the superficial back line (SBL) using separate conditions of active range of motion with and without resistance and passive range of motion. Using surface electromyography, electrodes were placed at specific points along the SBL. Twenty healthy adult males (aged 25.35 ± 1.24 years and body mass index 23.78 ± 2.12) underwent five test conditions. Conditions 1-3 involved passive movement, active movement and active movement against maximum isometric resistance (IR) of the right gastrocnemius and conditions 4 and 5 involved neck extension without and with isometric resistance from prone position. Passive and active motion without resistance found no significant (p > 0.05) correlations at any electrodes. Maximum IR yielded significant (p < 0.05) correlations with medium to very strong correlations at almost all electrodes. Neck extension without and with resistance showed significant medium to very strong correlations though the posterior superior iliac spine and right hamstring, respectively. Results demonstrated significant associations between the test condition muscle activations and muscle activations along the contiguous SBL. Thus, showing a need for a complete evaluation of the SBL in patients suffering from myofascial pain at all locations along it.

Multi-Walled Carbon Nanotubes/Graphene Oxide Composites for Humidity Sensing

Based on good dispersion of multi-walled carbon nanotubes (MWCNTs) in graphene oxide (GO) solution, MWCNTs/GO composite film was fabricated on a quartz crystal microbalance (QCM) by a simple drop-casting method. The composite responds quickly to relative humidity changes. The QCM with MWCNTs/GO coating showed the highest sensitivity among the QCMs coated with different films (MWCNTs, GO, and MWCNTs/GO). By monitoring changes in both the resonant frequency and impedance of the QCM sensors, it is found that the motional resistance and the quality factor (Q) of the QCM with MWCNTs/GO film have remarkable changes as compared with the QCM with GO film, which is suspected to be related with the viscosity of the sensing film. Meanwhile, the addition of MWCNTs may enlarge the distance between the GO sheets in composites and might be beneficial to the diffusion of water molecules. This study demonstrates that the MWCNTs/GO composite could be used for high sensitive humidity detection.

Analysis of existing and perspective methods of defining air resistance in projectiles motion

The article provides an insight into theoretical and practical methods of defining air resistance in projectile motion - fire method, aerodynamic method and mathematical (numerical) methods. Issues concerning their implementation are analyzed, existing and perspective approaches to approximation of aerodynamic resistance functions are investigated, and perspective trends of their development are specified.

Design of a New Bionic Swimming Robot for Vascular Unclogging

In this paper, a new 6-DOF bionic swimming robot with two screw propellers and one balance paddle is designed. This robot can swim up-and-down and roll without any effect on forward motion. The spiral swimming method is modeled and analyzed firstly. In order to optimize the bionic robots structures, the motion resistance and propulsive force are simulated and calculated. Also, experiments are performed to verify the action principle and the optimal analysis results of the robot. Key words:Bionic, Micro swimming robot, vascular unclogging, paddle

Adaptation Planning Guideline and Constrained Outline for Shower Chairs and other Four-Caster Vehicles

Introduction: No research-based guidelines for adaptation planning for shower chairs and other vehicles with four casters exist, despite the manual handling nature of the manoeuvring task and the occupational therapy responsibility to plan for such vehicles. Method: It was determined from theory that changes in direction for these vehicles, such as from a passageway through a door, could be represented by 13 manoeuvres. Participants (n = 17) carried out 11 (maximum) manoeuvres based on this theory, each with the maximum comfortable occupant weight of their choice (weights represented the occupant). Findings: The maximum occupant weight selected as comfortable varied substantially between some of the 11 manoeuvres: there was a 100% difference between the lowest and highest weight selections. This indicated that four-caster vehicles (such as shower chairs) should not be treated as omni-directional for high occupant weights, or for floor materials with high motion resistance, because the manoeuvre direction substantially affects maximum comfortable weight selection. Conclusion: The manoeuvre with the highest weight selection is proposed as a guideline when manual handling concerns exist for these vehicles. The guideline can be modified for individual vehicles sizes, occupant and carer anatomy.

Cyclic Fatigue Resistance of K3, K3XF, and Twisted File Nickel-Titanium Files under Continuous Rotation or Reciprocating Motion

IntroductionNew designs and alloys and different motions have been introduced to increase the cyclic fatigue (CF) resistance of nickel-titanium (NiTi) files. The aim of this study was to compare the CF resistance of K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and TF (SybronEndo) files under continuous rotation and reciprocating motion. MethodsA total of 210 files (30-tip diameter, 0.06 fixed taper), 60 K3, 60 K3XF, and 90 TF files, were divided into 7 groups (30 files each): K3-C, K3XF-C, and TF1-C were rotated at 300 rpm; TF2-C was rotated at 500 rpm; and K3-R, K3XF-R, and TF1-R were used in a reciprocating motion. CF resistance was tested in stainless steel, curved canals (60°, r = 3 mm) until fracture, and the time to fracture was recorded. The mean half-life, beta, and eta were calculated for each group and were compared with Weibull analysis. ResultsThe probability of a longer mean life was greater under reciprocating motion for all of the files (100% for K3, 87% for K3XF, and 99% for TF). Under continuous rotation, K3XF was more resistant than K3 and TF. TF lasted significantly longer than K3. TF was more resistant to CF when rotated at 300 rpm instead of 500 rpm. Under reciprocating motion, there were no significant differences between K3XF and TF mean lives, but both were significantly longer than the K3 mean life (78% for TF and 86% for K3XF). ConclusionsReciprocating motion and R-phase increase CF resistance.

Physical Theory of Useful Strength of Metallic Crystals*

Within the proposed concept of useful, i.e., excluding fracture, strength of metallic crystals, theoretical and experimental studies on the physical nature of microyield and dislocation stress relaxation were carried out. Activation analysis of the intermittent (repeated) dislocation pinning mechanism was performed and the contributions of mechanical interaction and thermal activation of anchored dislocations are shared that ensure escaping the short-range barriers in the nanovolumes of primary α-solid solutions. It is shown that in case of the examined mechanism, thermoactivated stress tends to the athermic component with relaxation time, and energy, applied to the barriers by the thermofluctuation mechanism, increases linearly up to the potential dislocation motion resistance barrier. The physical (dislocation) criterion of useful strength was formulated, accounting for the crystalline and faulted structure effects on the shear band localization in the process of microscopic strain accumulation below the macroscopic yield stress. Theoretical investigations of stress relaxation are consistent with the data, produced for new experimental alloys of a Mg–Al–Ca (Ti) system with improved creep resistance (with allowance for the strain e ~ 0.2–0.4% at $ \dot{\varepsilon} $ ~ 10-9 – 10-10 s-1) and strength (70 MPa for 200 h without fracture) characteristics, enhancing the thermal stability of the dislocation structure by 423–473 K.

Theory and validation of the motion resistance mechanism of four-caster manual vehicles

The four-caster manually manoeuvred vehicle is a crucial device for goods movement and disability transport. While there are manual handling related health and safety concerns, no dynamical theoretical-empirical investigation exists. Theoretical examination demonstrates that, in loose terms, the motion resistance effects are affected by vehicle-frame translational velocity direction: the proportion of the moment effect to translational effect produced by motion resistance varies in a highly non-linear way depending on the vehicle-frame velocity direction. An empirical study is devised from the theory. As the intention was to investigate the presence of this phenomenon in real use, human operators were used: they made planar manoeuvres from static equilibrium with a self-selected load while attempting to maintain 11 (maximum) different centres of zero velocity which related to the velocity directions. Results demonstrate that (1) the proportion of moment motion resistance effect to translational motion resistance effect does vary and (2) it is motion resistance rather than inertial forces which are the first-order effect. These results are an essential first step in understanding the manoeuvring difficulties and health and safety issues which arise with these vehicles.

Cement embolism into the venous system after pedicle screw fixation: case report, literature review, and prevention tips

The strength of pedicle screws attachment to the vertebrae is an important factor affecting their motion resistance and long term performance. Low bone quality, e.g. in osteopenic patients, keeps the screw bone interface at risk for subsidence and dislocation. In such cases, bone cement could be used to augment pedicle screw fixation. But its use is not free of risk. Therefore, clinicians, especially spine surgeons, radiologists, and internists should become increasingly aware of cement migration and embolism as possible complications. Here, we present an instructive case of cement embolism into the venous system after augmented screw fixation with fortunately asymptomatic clinical course. In addition we discuss pathophysiology and prevention methods as well as therapeutic management of this potentially life-threatening complication in a comprehensive review of the literature. However, only a few case reports of cement embolism into the venous system were published after augmented screw fixation.

Design and characterization of AlN-based in-plane microplate resonators

In this paper, a design procedure to perform an efficient actuation of in-plane modes in piezoelectric resonators is presented. This procedure is applied to different microplate structures, paying attention to two in-plane mode families: contour modes and flexure-actuated modes. A representative set of devices from both families were used as illustrative examples. These devices were characterized electrically by measuring the impedance and their in-plane modal shapes were measured with a novel technique based on speckle-pattern interferometry. Figures of merit such as the quality factor or the motional resistance were obtained and used to evaluate the different design approaches.

High-Frequency Thin-Film AlN-on-Diamond Lateral–Extensional Resonators

In this paper, low-impedance lateral–extensional microresonators are fabricated on a stack of aluminum nitride (AlN) directly deposited on a polished ultrananocrystalline diamond (UNCD) film. The large acoustic velocity of UNCD is utilized to extend the frequency of such resonators beyond 1 GHz while the frequency-defining features are not reduced excessively. In order to promote the growth of a &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX"&gt;$c$&lt;/jats:tex&gt; &lt;/jats:formula&gt;-plane piezoelectric AlN film, the surface of the UNCD film is polished after deposition. Three different UNCD films with different Young's modulus values were prepared, and frequencies up to two times that of similar devices fabricated on silicon have been achieved. The finite-element analysis is employed to evaluate the effect of various physical parameters on the performance of the thin-film piezoelectric-on-substrate resonators in order to achieve very low motional resistance &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX" &gt;$(R_{m})$&lt;/jats:tex&gt;&lt;/jats:formula&gt;. Several resonators were designed with various lateral dimensions and different numbers of support tethers to evaluate the propositions. The lowest &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX" &gt;$R_{m}$&lt;/jats:tex&gt;&lt;/jats:formula&gt; was measured from a multitethered 29th-order thin-film piezoelectric-on-diamond (TPoD) resonator (22 &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX"&gt; $Omega$&lt;/jats:tex&gt;&lt;/jats:formula&gt;) and &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX"&gt;$fcdot Q$&lt;/jats:tex&gt;&lt;/jats:formula&gt; product of &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX"&gt;$2.72 ast 10^{12}$&lt;/jats:tex&gt;&lt;/jats:formula&gt; at 888 MHz. The temperature coefficient of frequency of this TPoD resonator is measured to be &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX"&gt;$-9.6 hbox{ppm}/^{circ} hbox{C}$&lt;/jats:tex&gt;&lt;/jats:formula&gt;, which is much lower than that of the devices fabricated on silicon. Also, this device can withstand input powers up to &lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX"&gt;$+$&lt;/jats:tex&gt;&lt;/jats:formula&gt;27 dBm, leading to a delivered power density per unit area of &lt;jats:formula formulatype="inline" &gt;&lt;jats:tex Notation="TeX"&gt;$sim!!2.9 muhbox{W}/muhbox{m}^{2}$&lt;/jats:tex&gt; &lt;/jats:formula&gt;.&lt;jats:formula formulatype="inline"&gt;&lt;jats:tex Notation="TeX" &gt;$hfill$&lt;/jats:tex&gt;&lt;/jats:formula&gt;[2012-0099]

Acoustic detection of cell adhesion to a coated quartz crystal microbalance – implications for studying the biocompatibility of polymers

Biocompatibility of polymers is an important parameter for the successful application of polymers in tissue engineering. In this work, quartz crystal microbalance (QCM) devices were used to follow the adhesion of NIH 3T3 fibroblasts to QCM surfaces modified with fibronectin (FN) and poly-D-lysine (PDL). The variations in sensor resonant frequency (Δf) and motional resistance (ΔR), monitored as the sensor signal, revealed that cell adhesion was favored in the PDL-coated QCMs. Fluorescence microscopy images of seeded cells showed more highly spread cells on the PDL substrate, which is consistent with the results of the QCM signals. The sensor signal was shown to be sensitive to extracellular matrix (ECM)-binding motifs. Ethylenediaminetetraacetic acid (EDTA) and soluble Gly-Arg-Gly-Asp-Ser (GRGDS) peptides were used to interfere with cell-ECM binding motifs onto FN-coated QCMs. The acquired acoustic signals successfully showed that in the presence of 30 mM EDTA or 1 mM GRGDS, cell adhesion is almost completely abolished due to the inhibition/blocking of integrin function by these compounds. The results presented here demonstrate the potential of the QCM sensor to study cell adhesion, to monitor the biocompatibility of polymers and materials, and to assess the effect of adhesion modulators. QCM sensors have great potential in tissue engineering applications, as QCM sensors are able to analyze the biocompatibility of surfaces and it has the added advantage of being able to evaluate, in situ and in real time, the effect of specific drugs/treatments on cells.