Motional Resistance Research Articles

Performance Evaluation of Adaptive Neural Fuzzy Inference System for Sediment Transport in Sewers

The application of models capable of estimating sediment transport in sewers has been a frequent practice in the past years. Considering the fact that predicting sediment transport within the sewer is a complex phenomenon, the existing equations used for predicting densimetric Froude number do not present similar results. Using Adaptive Neural Fuzzy Inference System (ANFIS) this article studies sediment transport in sewers. For this purpose, five different dimensionless groups including motion, transport, sediment, transport mode and flow resistance are introduced first and then the effects of various parameters in different groups on the estimation of the densimetric Froude number in the motion group are presented as six different models. To present the models, two states of grid partitioning and sub-clustering were used in Fuzzy Inference System (FIS) generation. Moreover, the training algorithms applied in this article include back propagation and hybrid. The results of the proposed models are compared with the experimental data and the existing equations. The results show that ANFIS models have greater accuracy than the existing sediment transport

Ship synthesis model for the preliminary design of a fleet of compressed natural gas carriers

The transportation by sea of compressed natural gas is a very recent subject, prompted by recent changes in the perspectives of a possible economic exploitation of relatively small quantities of this hydrocarbon, available as by-product of oil extraction in off-shore fields. An automatic and integrated preliminary design procedure has been established to generate and evaluate feasible technical solutions for a trade of this kind. A first trial application has been carried out for a specific case, for which various feasible solutions corresponding to fleets composed of a different number of equal ships are generated.In the procedure, a parent hull shape is adopted in order to evaluate, through systematic variations of the main dimensions, all the elements necessary to perform the classical steps of the design spiral (like weight evaluation, buoyancy, trim and stability checks and motion resistance prediction) accounting for the mutual interaction between the various items. When possible and necessary, parts of the procedure have been calibrated with data from existing ships, in order to ensure realism in the predictions. This has been done with reference e.g. to the evaluation of weight items and in particular to hull weight. On the other hand, when setting boundaries to the range of variation in the ship dimensions, care has been given not to constrain the investigation domain only to existing dimensional ratios, but to let the procedure explore a wider range of solutions. A particular feature of the procedure is to include in the evaluation process the seakeeping performances in terms of added resistance in waves. This aspect interacts with the other part of the design process and influences the final outcome in terms of performance of the solution. The main implications of accounting for the increase in motion resistance are the capability of evaluating the reduction in the average speed, the corresponding reduction in the annual cargo delivery and the increase in fuel consumption (all aspects evaluated in respect to nominal conditions). The procedure, accordingly, is able to provide, in addition to several technical output identifying the various solutions (such as main dimensions, weight, power installed, seakeeping performances), indicators of the performances of the fleet in terms of annual cargo delivery, CapEx and OpEx, that can be used to rank the various solutions.

The slope effect of a capacitive resonator profile fabricated by a DRIE process on the performance of an MEMS disk resonator

The thickness of a capacitive disk resonator can be increased by selecting a deep reactive ion etching (DRIE) process for reducing motional resistance. However, the DRIE process sometimes causes MEMS capacitive resonators to have a non-ideal profile. In this paper, the slope effect of a resonator profile fabricated by a DRIE process on the capacitance, electrostatic force, electrical stiffness, motional resistance and output current of the capacitive resonator is analyzed. The relation curves between these parameters and the sloped angle are obtained theoretically. The results show that the capacitance, electrostatic force, electrical stiffness and output current decrease as the sloped angle increases, but the motional resistance obviously increases. By capturing the electric field distribution of a capacitive resonator with different ratios of the gap to thickness by using FEM software ANSYS, the effects of slope angle and thickness on the natural frequency of the resonator are investigated. The analyzed results can provide the theoretical basis for designing high-performance MEMS disk resonators fabricated by the DRIE process.

Motional Resistance Issue of TSV-Based Resonator Device and Its Improvement With a Concave Cu TSV Structural Design

Motional resistance of TSV-based resonator devices with 3D integration techniques is investigated at the operating oscillating mode. Even with well-developed TSV and device fabrication, the motional resistance issue of the TSV-based resonator device is found due to the poor connected Ag paste. The corresponding solution is demonstrated by a modified concave Cu TSVs structure. This modified concave Cu TSV design shows the excellent device characteristics and no visible gaps between the Cu TSVs and resonator devices to insure a good electrical connection.

Design of a novel RF MEMS square resonator

A novel kind of RF MEMS square resonator with a movable electrode structure that is driven by electrostatic force is proposed. Within the scope of the fabrication process allowed, the gap between the movable electrode and resonance square is decreased from 2.5 to 0.5 μm, which greatly reduces motional resistance so that resonator is easier to resonate. Then the DC driving voltage that makes electrode move setting displacement is deduced theoretically. The finite element simulation and analysis software ANSYS are used to validate mechanical vibration modal and determine center frequency of resonator. In addition, simulation of harmonic analysis is applied to obtain the change of output current and motional resistance before and after the electrode moving. Moreover, the design can also, to a certain extent, ease the difficulty of manufacturing the small gap in the micro-processing technology.

PHASE FIELD CRYSTAL SIMULATION OF STRAIN EFFECTS ON DISLOCATION MOVEMENT OF PREMELTING GRAIN BOUNDRIES AT HIGH TEMPERATURE

The properties of modern materials, especially superplastic, nanocrystalline or composite materials, depend critically on the properties of internal interfaces such as grain boundaries(GBs) and interphase boundaries(IBs). All processes which can change the properties of GBs and IBs affect drastically the behaviour of polycrystalline metals and ceramics. In this work, the annihilation processes of low-angle symmetric tilt GBs and dislocations during plastic deformation in the representative system of these materials near but below the melting point and the temperature at liquid-solid coexistence line were simulated using the phase-field crystal model, respectively. The results show that local premelting occurs around lattice dislocations near the melting point but the dislocation structure in the premelting region does not change, while the region become significantly larger when the system reaches the melting temperature. After premelting, deformation to the system causes dislocations in the premelting GB to begin to glide then annihilate with opposite Burgers vectors via the movement, finally the GB and the premelting region disappear. The annihilation mechanisms of dislocations are similar to those for premelting conditions. The more the temperature is closer to the melting point, the more obvious the atomic lattice around the premelting region is softened leading to the atomic binding strength around the dislocations being lowered. Only at this moment, the lattice atoms enable to reduce the resistance of the dislocation motion and accelerate its velocity during deformation. At the temperature reaching to the liquid-solid coexisting region in the simulation, the original premelting regions are induced to develop into bigger ones by the external strain acting. During this process, it can be seen some interactions including the multiplication dislocation pairs, the rotation of dislocation pairs and their annihilation. Furthermore, the shape of the premelting region changes with the variation of the interaction of dislocations inside the region, it is observed that the premelting regions approach each other and consolidate together,then decompose and segregate from each other. Although the shape of the premelting region changes with the applied strain, these regions do not disappear at the end of the simulation, totally different those in lower premelting temperature.

Mechanical quality factor enhancement in a silicon micromechanical resonator by low-damage process using neutral beam etching technology

The fabrication and evaluation of silicon micromechanical resonators using neutral beam etching (NBE) technology is presented. An etching technique based on a low energy neutral beam of Cl2/F2/O2 is introduced for making nano-trench patterns on 5 µm-thick silicon. The NBE technology has been investigated to form a highly-anisotropic etching shape. A 5 μm-deep trench pattern having smooth side walls with a gap width of 230 nm is achieved by using NBE. Additionally, a fabrication method for silicon resonators using NBE technology is proposed. The resonant frequency of the fabricated devices with a length of 500 μm, width of 440 μm and thickness of 5 μm is 9.66 MHz, and the average quality factor (Q) value is around 78 000. The devices fabricated by both deep reactive ion etching (DRIE) and NBE are evaluated and compared. The devices fabricated by NBE show that the motional resistances are reduced by almost 11 times from 645 kΩ to 59 kΩ and their output signals (insertion loss) are increased by approximately 15 dB in comparison with those fabricated by DRIE. Especially, devices fabricated by NBE provide the higher Q factors (average Q factor value of around 78 000) than those (average Q factor value of around 61 000) fabricated by DRIE in the same resonator parameters and measurement conditions.

Design and Analysis of Hydraulic Piston Structure Exciter

The movement characteristics of hydraulic exciting piston is a small displacement and high reversing frequency. The movement of the piston is to adapt to the requirement of quick reversing resistance. The mating surface seal uses to reduce the motion resistance to meet the requirements of the piston movement. Piston position should be in the oil chamber oil area to meet the requirements of the piston movement and oil circulation. Elastic beam with hydraulic cylinder is connected together . This structure is conducive to the piston and the connection of elastic beam and the installation of the oil cylinder. The causes of the different moving displacement of piston is leaking.

Analysis of reliability factors of MEMS disk resonator under the strong inertial impact

Increasing the bias voltage is a method of reducing the motional resistance of the capacitive disk resonator to match the impedance of the RF circuit. But there are few reports on the study of reliable working range of bias voltage under the shock and vibration environment. Therefore, the reliability of disk resonator under the step and pulse acceleration impact respectively is systematically analyzed in this paper. By the expression of the biggest inertial acceleration the disk can bear under the reliable condition, the maximal reliable range curves of the disk resonator under the dynamic impact environment are obtained. According to the actual sizes of disk in the literature, it can be seen that when a step shock of 13000g is supplied, the reliability range is reduced to 75% compared with the original state. For the pulse shock, the reliability range is related to the pulse amplitude and time width. Research of this paper can provide the basis for the selection of bias voltage of disk resonator under the inertial shock.

Design of a novel MEMS resonator based neuromorphic oscillator

A novel MEMS based neuromorphic oscillator is presented. Due to compatibility with CMOS process, on-chip integration of electro-statically actuated microresonators is possible with very small size. Also, taking advantage of sacrificial sidewall spacer technique for fabrication of 100nm vertical gap, as low actuation voltages as 0.5V is enough for such resonators. Oscillatory neuron dynamics are also studied and design of the resonator and its characteristics are described as a neuromorphic oscillator. There are several practical barriers associated with MEMS implementation of neuromorphic oscillators such as existence of near-to-main mode spurious modes, requiring of UHF high gain trans-impedance amplifier because of very high motional resistance of such resonators, and automatic amplitude control circuit which all investigated in the paper and surmounted as well. A coupling technique for weak connection of such resonators is also described in the paper which allows mechanical low velocity connection of UHF contour mode disk resonators for the first time.

Relations Between Anthropometric Dimensions and Overcome Resistance in Recurring Motion

The research was carried out on a sample of 124 subjects, 15-16 year old males. An analysis was performed of the relations of anthropometric body characteristics and overcome resistance in recurring motion. The evaluation of resistance in motion was based on conducting motion with 75% of the maximum achieved, overcome weight, repetitive motion is carried out until the maximum number of correctly executed repetitions. Obtained information was submitted for mathematical analysis, the MULTREG program, from the statistical program “STAT – PACK” (Gauss – Jordan, 1954, Cooley – Lohnes, 1962). On the basis of maximum cohesion and regressive coefficients, variables that measured body volume, transversal skeletal dimension and longitudinal skeletal dimension have the highest cohesion with the overcome maximum resistance in recurring motion from anthropometric body characteristics. High cohesion of variables of the overcome resistance in recurring motion with anthropometric body characteristics indicates that a part of the resistance variable in motion is expectedly significant. As the overcome maximum resistance in motion is mainly conditioned by the structure for generating intensity and duration of energy release, thus the anthropometric dimensions, especially in the volume segment, body volume and transversal skeletal dimensionality, present a factor that significantly participates in the realization of motion with increased requirements for overcoming maximum resistance in motion.

De la rhéologie à la pratique

In this paper, composition of water, amorphous gel and rheology properties of fly ash-slag based geopolymer fresh pastes have been investigated by 1H low-field NMR(LF-NMR), in-situ ATR FTIR and Brookfield DV3T rheometer under the different NaOH content. T2 relaxation time of LF-NMR and gel characteristic peak of pastes was obtained to accurately study the influence of free water and gel on the fresh pastes. Results indicate the high transformation speed of free water and quicker formation speed of gel result to the more fluidity loss of geopolymer pastes. N-A-S-H and C-(A)-S-H gel were major reasons on the development of rheology properties. Higher water-binding ability of C-(A)-S-H gel may accelerate the transformation of free water to the gel water, which could increase the motion resistance of particles. It would result to the increasing of rheology peoperties and decreasing of fluidity of geopolymer fresh pastes.

Comparative Analysis of Cellular Prion Detection by Mass‐Sensitive Immunosensors

AbstractWe performed a comparative study of the detection of human cellular prions (PrPC) with a quartz crystal microbalance (QCM) immunosensor using various antibodies against PrPC. The sensing layer was formed by immobilized antibodies on a surface of polyamidoamine dendrimers (PAMAM) of fourth generation (G4) with attached protein A. The sensitivity of detection depended on the kind of antibody used and the best detection limit was 0.8 nM. PrPC detection in 10 times diluted blood plasma revealed more complicated behavior of motional resistance, which is evidence on viscosity contribution. The sensor recovery was 82.2 %, suggesting certain matrix effects on prion detection.

Effects of gravity on rigid rover wheel sinkage and motion resistance assessed using two-dimensional discrete element method

Elucidating the effects of gravity on rover/rover wheel performance is important because it can provide a basis for predicting their performance on extraterrestrial surfaces based on test results obtained on Earth. Results of previous studies by Wong (2012) and by Wong and Kobayashi (2012) indicate that if in conducting performance testing of rovers/rover wheels on Earth with identical mass to that on the extraterrestrial surface, instead of with identical normal load (force) used in the current practice, their performance on the extraterrestrial surface can be predicted based on test results obtained on Earth. As described herein, the effects of gravity on rigid rover wheel sinkage and motion resistance were investigated using the two-dimensional discrete element method. The rover wheel mass is unchanged under various gravity conditions. The results of this study substantiate the findings presented in Wong (2012) and Wong and Kobayashi (2012). Given identical mass, the sinkage of a rigid rover wheel under Earth gravity g is the same as that under a different gravity gex: 1/6g–2g. It is also shown that the ratio of the motion resistance of a rigid rover wheel under gravity gex to that under Earth gravity g is equal to the ratio gex/g.

Extensive domain wall motion and deaging resistance in morphotropic 0.55Bi(Ni1/2Ti1/2)O3–0.45PbTiO3 polycrystalline ferroelectrics

Domain wall motion is known as a major source of extrinsic contributions to the dielectric and piezoelectric properties of ferroelectric materials. In the present work, we report the extent of non-180° domain wall motion during strong and weak electric field amplitudes in situ using time-resolved, high-energy X-ray diffraction in the ferroelectric morphotropic phase boundary composition 0.55Bi(Ni1/2Ti1/2)O3–0.45PbTiO3 (BNT-45PT). After application of strong electric fields, two phases are shown to coexist. In the tetragonal phase of this material, the extent of 90° domain wall motion is significant and the domain alignment is nearly saturated. Weak (subswitching) cyclic electric fields are then also shown to induce domain wall motion. Deaging, or the progressive loss of preferred domain orientation during sequentially increasing field amplitudes, is notably low in these materials, showing that the initial domain alignment is strongly stabilized. Overall, the in situ measurements reveal that domain wall motion significantly impacts the structure and properties of BNT-45PT and reinforces the importance of understanding domain wall motion contributions to the physical properties of ferroelectrics.

Concanavalin A–Polysaccharides binding affinity analysis using a quartz crystal microbalance

There is no comparative data available on the binding constants of Concanavalin A (Con A) and glycogen and Con A–mannan using quartz crystal microbalance (QCM), cost and time efficient system for biosensor analysis. It is hypothesized that a QCM can be used in its flow injection mode to monitor the binding affinity of polysaccharides to an immobilized lectin, Con A. The biosensor is prepared by immobilizing Con A on a 5MHz gold crystal by carbodiimide crosslinking chemistry. The attachment efficiency is monitored by Fourier Transform Infrared Spectroscopy. Equilibrium association and dissociation constants describing Con A–polysaccharides interaction are determined in a saturation binding experiment, where increasing concentrations of polysaccharides are run on a Con A-immobilized gold crystal surface, and the frequency shifts recorded on the frequency counter. The molecular weights (MW) of glycogen from Oyster and mannan from Saccharomyces cerevisiae are determined by size exclusion chromatography. The MW for glycogen and mannan are 604±0.002kDa and 54±0.002kDa, respectively. The equilibrium association and dissociation constants for Con A–glycogen and Con A–mannan interactions are KA=3.93±0.7×106M−1/KD=0.25±0.06μM and KA=3.46±0.22×105M−1/KD=2.89±0.20μM (n=3), respectively. Their respective frequency and motional resistance shifts relationship (ΔF/ΔR) are 37.29±1.55 and 34.86±0.85Hz/Ω (n=3), which support the validity of Sauerbrey׳s rigidity approximation. This work suggests that Con A–mannan complex could be potentially utilized for insulin delivery and the targeting of glucose-rich substances and glycoproteins when fast drug release is desired.

A 10-MHz SOI-Based Face Shear Square Micromechanical Resonator

A 10-MHz face shear (FS) square micromechanical resonator based on silicon-on-insulator (SOI) technology is presented in this paper. In order to examine the improvement of quality factor as well as motional resistance Rx in this structure, the center-stem anchor is employed in this study. The benefit of anchoring the square in the center, which is the nodal point, is that the energy losses through the anchor can be minimized. Hence, a quality factor value of 2.0 million and the motional resistance of 8.2 kΩ can be obtained with an FS mode resonator via finite element (FE) simulation. The results show the significance of the FS mode in this design, not only in its structure but also in its square-extensional mode and Lame-mode. Additionally, an SOI-based fabrication process is proposed to support the design.

An Electrochemical Quartz Crystal Microbalance Study of a Prospective Alkaline Anion Exchange Membrane Material for Fuel Cells: Anion Exchange Dynamics and Membrane Swelling

A strategy has been devised to study the incorporation and exchange of anions in a candidate alkaline anion exchange membrane (AAEM) material for alkaline fuel cells using the electrochemical quartz crystal microbalance (EQCM) technique. It involves the electro-oxidation of methanol (CH3OH) under alkaline conditions to generate carbonate (CO3(2-)) and formate (HCOO(-)) ions at the electrode of a quartz crystal resonator coated with an AAEM film, while simultaneously monitoring changes in the frequency (Δf) and the motional resistance (ΔR(m)) of the resonator. A decrease in Δf, indicating an apparent mass increase in the film, and a decrease in ΔR(m), signifying a deswelling of the film, were observed during methanol oxidation. A series of additional QCM experiments, in which the effects of CH3OH, CO3(2-), and HCOO(-) were individually examined by changing the solution concentration of these species, confirmed the changes to be due to the incorporation of electrogenerated CO3(2-)/HCOO(-) into the film. Furthermore, the AAEM films were found to have finite anion uptake, validating the expected tolerance of the material to salt precipitation in the AAEM. The EQCM results obtained indicated that HCOO(-) and CO3(2-), in particular, interact strongly with the AAEM film and readily displace OH(-) from the film. Notwithstanding, the anion exchange between CO3(2-)/HCOO(-) and OH(-) was found to be reversible. It is also inferred that the film exhibits increased swelling in the OH(-) form versus the CO3(2-)/HCOO(-) form. Acoustic impedance analysis of the AAEM-film coated quartz resonators immersed in water showed that the hydrated AAEM material exhibits significant viscoelastic effects due to solvent plasticization.

Numerical and Experimental Investigation of Plastic Interaction Between Rough Surfaces

The paper presents a dry friction model considering plastic interactions described by the Oxley equations. The model differs clearly from those published by Oxley due to the fact that it includes a statistical analysis of rough surface interactions. The contact of a single asperity is analyzed in a 3D—not 2D—space. The results of this analysis are further extended to the contact of two rough-surfaces by accomplishment of an appropriate summing (integration) of individual elementary forces of friction and pressure occurring in discreet contacts. In the case of papers based on the Oxley model, their authors analyze the contact of a single asperity with a plane and thus compute the macroscopic friction coefficient. On the basis of the achieved mathematical model of dry friction, the friction force was determined and consequently, the friction coefficient. In order to verify theoretical speculations, an experimental test was carried out in the system consisting of a steel disk with a galvanized coating and a steel pin. The results of experimental tests comply with the solutions achieved via a computer simulation. The resistance to motion results mainly from plastic deformations, which in turn result in adhesion tacking. Among investigated galvanic coatings, the highest motion resistance was revealed by a nickel coating, whereas the lowest one was revealed by a silver coating.

Magnetoresistance Characteristics of Magnetorheological Gel under a Magnetic Field

A kind of magnetoresistance material was prepared, named as magnetorheological gel (MRG). The MRG samples were fabricated by dispersing carbonyl iron particles (CIP) into the polyurethane gel, and several experimental devices were prepared to investigate the magnetoresistance characteristics of MRG. The magnetoresistance characteristic was systematically tested and the influence of the magnetic field was analyzed. It is found that the resistance value of MRG with the CIP content of 70 wt % can be decreased from 7.56 to 2.44 MΩ with increasing of magnetic field from 0.1 T to 1 T. The experimental results have also proved that CIP content and the composition of matrix have a greater impact on the magnetoresistance characteristics. Because of the interaction between the magnetic force of CIP and motion resistance under a magnetic field, the obvious hysteresis phenomenon was observed and recorded. Lastly, it was observed that the magnetoresistance can be changed reversibly by controlling the magnetic field.