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Inspired by the viscoelastic displacement theory, we have developed a product called preformed particle gel (PPG) as conformance control agent to enhance oil recovery and control excess water production. The migration law of PPG suspension in porous media is related to its deep profile control and displacement capability. Laboratory experiments indicate that PPG suspension has good viscosity increasing, and the apparent viscosity decreases with the increase of shear rate. PPG suspension is mainly elastic, and its network structure makes it have certain shear stability. PPG particles realize migration in porous media in the way of “accumulation and blockage→pressure increase→deformation and migration”. When the ratio of the PPG particle size to the pore throat diameter δ ranges from 35.52 to 53.38, the particles can match through the porous medium. When the permeability difference of the parallel model is 5, PPG suspension has the highest profile improvement rate, 69.10%. PPG suspension can adjust the planar heterogeneity, and increase the oil recovery rate by 20.75%. The PPG suspension can effectively start “cluster"、 “film” and “blind end residual oil”, and has a high oil washing efficiency. The core NMR T2 spectrum shows that PPG suspension mainly reduces oil saturation in mesopores and macropores. After PPG flooding, the EOR capacity of small pores is the highest, 39.11%.

Due to the increasing demand for high-speed motors with high stability, bearingless motors have attracted much attention. Bearingless permanent magnet synchronous motors (BPMSMs) are a kind of motor, which uses suspension force to eliminate the motor bearings. This article proposes a five-phase BPMSM with 10 slots and 8 poles. Based on the principle of suspension force of BPMSM, an analytical expression of the suspension force is derived for the proposed BPMSM. To improve the suspension stability and torque, an optimization method consisting of a response surface model and a multiobjective optimization algorithm is employed. Not only the geometric parameters but also the winding distribution are considered in the optimization process. Finally, the effectiveness and superiority of the optimal design are verified by experiment.

The suspension system is an important unit that affects vehicle performance, including handling stability and riding comfort. In order to improve vehicle performances, a novel robust optimal control strategy for the active suspension system in vehicles is proposed. To handle the parameter uncertainties and external random disturbances, the proposed optimal control strategy is designed by using the combination of the linear quadratic regulator (LQR) optimal control and sliding-mode control. First, by using the nominal model of the active suspension system without the uncertain parameters and the external random disturbances, an optimal control performance index is given, and the initial optimal controller is designed by using the LQR control strategy. Then, to handle the parameter uncertainties and the external disturbances, a robust optimal integral sliding-mode control strategy based on the initial optimal controller is designed, which not only can achieve the optimal control objective but also has good robustness to the uncertain parameters and external disturbances. By using the Lyapunov stability theory, stability analysis of the proposed robust optimal integral sliding-mode control strategy is performed. Finally, the collaborative simulation platform based on the Carsim and MATLAB/Simulink is developed. The simulation results illustrate the advantage of the proposed robust optimal control strategy for the suspension system.

Air suspension system is been used by vehicle manufacturers since decades. Earlier it was only used by the commercial vehicle but soon the manufacturers and the users found the need of air suspension in commercial vehicles as well. Nowadays this system can mostly be seen in luxury vehicles, the application of air suspension has come a long way, earlier when it was installed in commercial vehicles, it was generally used for raising and lowering ride height to accommodate different sizes of trails, but later air suspension system majorly started to be used as a luxury feature because manufacturers invented that it was providing supreme ride and comfort especially when comparing with traditional spring mechanism used in suspension. Therefore all the luxury cars are using air suspension to provide supreme comfort during riding even through rough terrains. This paper discusses about the different applications of air suspension discussing about the working and its advantages and disadvantages.

This investigation aims to study a novel biologically derived coating applied on Ti alloy substrates. Obtained from a low-cost fish bone resource, a nanocrystalline hydroxyapatite has been synthesized and converted to an organic suspension. Coating was then manufactured by a high-velocity suspension flame spray process. The microstructure, phase composition, coating thickness, and roughness of hydroxyapatite (HA)-coated samples were studied. The results indicated the presence of both hydroxyapatite and β-tricalcium phosphate phases and the final coating layer was uniform and dense. In vitro bioactivity and biodegradability of the HA/Ti composite samples were estimated by immersion in simulated body fluid. Remarkable reductions in Ca2+ and PO43- ion concentrations were observed as well as low weight loss percentage and a slight variation in the pH value, indicating the generation of an apatite layer on the surface of all studied samples. Scanning electron microscopy, energy-dispersive x-ray analysis, and inductively coupled plasma–optical emission spectrometry confirm these results. Thus biological derived HA coatings are a promising candidate to enhance bioactivity and biodegradability of bone implants. To demonstrate feasibility on commercial medical components, a medical screw was coated and evaluated., Science & Technology Development Fund (STDF), Projekt DEAL

A reliable, efficient, and simple control is presented and validated for a quarter-car active suspension system equipped with an electro-hydraulic actuator. Unlike the existing techniques, this control does not use any function approximation, e.g., neural networks (NNs) or fuzzy-logic systems (FLSs), while the unmolded dynamics, including the hydraulic actuator behavior, can be accommodated effectively. Hence, the heavy computational costs and tedious parameter tuning phase can be remedied. Moreover, both the transient and steady-state suspension performance can be retained by incorporating prescribed performance functions (PPFs) into the control implementation. This guaranteed performance is particularly useful for guaranteeing the safe operation of suspension systems. Apart from theoretical studies, some practical considerations of control implementation and several parameter tuning guidelines are suggested. Experimental results based on a practical quarter-car active suspension test-rig demonstrate that this control can obtain a superior performance and has better computational efficiency over several other control methods.

We investigated the solid–liquid suspension characteristics in the tank with a liquid height/tank diameter ratio of 1.5 stirred by a novel long-short blades (LSB) impeller by the Euler granular flow model coupled with the standard k–e turbulence model. After validation of the local solid holdup by experiments, numerical predictions have been successfully used to explain the influences of impeller rotating speed, particle density, particle size, liquid viscosity and initial solid loading on the solid suspension behavior, i.e. smaller particles with lower density are more likely to be suspended evenly in the liquid with higher liquid viscosity. At a low impeller rotating speed (N), increase in N leads to an obvious improvement in the solid distribution homogeneity. Moreover, the proposed LSB impeller has obvious advantages in the uniform distribution of the solid particles compared with single Rushton turbine (RT), dual RT impellers or CBY hydrofoil impeller under the same power consumption.

The rotating characteristic and the stability analysis of unsymmetrical magnetically suspended motor (MSM) are investigated in the article. Firstly, the dynamic functions of unsymmetrical MSM with different moment of inertia ratios and suspension span ratios are developed. Based on the equation of radial rotation, the open-loop pole and the frequency response are analyzed, so relationships among critical whirling frequency, moment of inertia ratio and suspension span ratio are established. Moreover, relationships among rotating characteristic, moment of inertia ratio and suspension span ratio are investigated, and then the rotation stability criterion of unsymmetrical MSM based on dual-frequency bode diagram is developed. Finally, the results prove that the proposed rotation analysis method is a potential way to analyze rotating characteristic of unsymmetrical MSM.

In this paper, afull-car prototype of the recently proposed mechatronic suspension, Series Active Variable Geometry Suspension (SAVGS), is developed for on-road driving experimental proof of concept, aiming to be adopted by suspension OEMs (original equipment manufacturers) as an alternative solution to fully active suspensions. Particularly, mechanical modifications are performed to both corners of the front double-wishbone suspensionof a production car, with active single-links attached to the upper-ends of the spring-damper units, while both corners of the rear suspension remain inthe original (passive) configurations.The mechanical modifications involve innovatively designed parts to enable the desired suspension performance improvements, while maintaining ride harshness at conventional levels.Areal-time embedded system is further developed to primarily implement:1) power supply, data acquisition and measurementsof the vehicle dynamics related variables, and 2) robust control application for the ride comfort and road holding enhancement, which is based on a derived linearized model of the full-car dynamics and a newly synthesizedH-infinity control scheme. Results obtained from on-road driving experiments are inessential agreement with numerical simulation results also produced. Overall, the full-car prototypeof SAVGS demonstrates promising suspension performance,with anaverage 3 dB attenuation (or equivalently 30% reduction) of the chassis vertical acceleration at aroundthe human-sensitive frequencies (2-5Hz),as compared to the original vehicle with the passive suspension system. More importantly, the prototype also indicatesthe practicality of the solution, as the SAVGS retrofit to a real car is achieved by simple mechanical modifications, compact actuator packaging, smallmass increment(21.5kg increase with respect to the original vehicle), limited power usage (an average value of 134W in DC batteries with a Class D random road) and acceptable economic cost.

Due to the existence of the end effect of the vehicle coils in the electrodynamic suspension maglev, the fluctuation of the output parameters of the suspension and guidance system is common, which has an impact on the stability of the motor driving system. In this paper, considering the end effect of vehicle coils, a new magnetomotive force distribution model suitable for the suspension and guidance system of electrodynamic suspension maglev is proposed. Firstly, considering the end effect of vehicle coils, a magnetomotive force model of array of vehicle coils is established. Then, based on space harmonic method and the equivalent circuit of suspension and guidance loop, the expressions of levitation current, guidance current, drag force, levitation force, levitation stiffness, guidance force and guidance stiffness are presented. Finally, the characteristics of the suspension and guidance system are analyzed under different running conditions. The numerical results are compared with the three-dimensional finite element method simulation results and the experimental results of the Yamanashi test line. The relative error is almost within 10%, which verified the feasibility and accuracy of the magnetomotive force model and analytical method.

The paper proposes maglev wind yaw system (MWYS) for wind turbine to yaw for wind. Two degree-of-freedom (2-DOF) suspension model is constructed with the suspension current dynamics. A dual-loop cooperative suspension control including inverse system compensation, pseudo suspension control and hybrid decoupling control is proposed to ensure nacelle stable suspension without pitching. The inverse system compensation gives the nominal current reference; and then the pseudo suspension control is designed from sliding mode controller with the non-linear function to acquire two pseudo control input, and then 2 DOF disturbance observers based on two sliding mode surfaces and their sign function are proposed to get high frequency interference, and cooperate with the linear relationship to decouple and give two sides current reference. The closed-loop stability of nacelle suspension has proved by the Lyapunov function, air gap asymptotic tracking can be reached in finite time. The state feedback controller with adaptive compensation is designed to enhance the current dynamic response. Finally, the simulation and experimental results show that the proposed strategy has faster suspension dynamic response, smaller steady-state error and synchronization error.

The coaxial mixers enhance the suspension of concentrated slurries in an agitated reactor. In this research work, the complex slurry suspension and dissemination behavior in a coaxial slurry mixing system (comprised of a close clearance anchor rotating with a low speed and an inner axial impeller rotating with a high speed) was analyzed employing ERT (electrical resistance tomography, a non-intrusive flow visualization technique), and computational fluid dynamics (CFD). The numerical models were validated by comparing the axial solid concentration profiles generated using the ERT data and the CFD simulation results. The influences of various important parameters such as the diameter of the inner axial impeller, the inner impeller type, and the inner impeller spacing on the hydrodynamic characteristics of the slurry suspensions in a coaxial mixing vessel were thoroughly analyzed. The radial and axial velocity profiles of solid particles were generated using the validated mathematical models. The assessment of energy loss due to the solid–solid collisions, the particle–fluid frictions, and the particle–vessel wall collisions was conducted. The evaluation of optimum inner impeller clearance and inner impeller diameter is essential to attain a high degree of solids suspension and dissemination in a coaxial slurry mixing system.

In the process of establishing a bearingless induction motor (BL-IM) traditional dynamic model, the magnetomotive force of rotor winding, the influence of suspension winding on torque, and the influence of torque winding on radial force are ignored. To solve the problem of insufficient accuracy in the traditional analytical model, based on fixed-pole rotor structure designed by the research group, which comprehensively considers the effect of suspension winding, torque winding and rotor winding, an optimized dynamic model is proposed. Firstly, the spatial variation equation of air gap under rotor eccentricity is established, and the composite magnetomotive force of three sets of windings according to the law of magnetic circuit is deduced, and the analytical model of magnetic co-energy in air gap is bulit. Secondly, using virtual displacement theorem to find partial derivative, the torque and radial force analytical model are obtained. Thirdly, the optimized BL-IM dynamic model is established. Finally, FEA (Finite element analysis) simulations based on controlled variable method prove the accuracy of optimized dynamic model and the change trend of torque is verified with respect to suspension current, phase difference between suspension current and torque current, as well as rotor eccentricity.

This paper proposes a novel semi-active electromagnetic device with the capability of variable inertance and damping (VIVD) and an energy storage priority control (ESPC) strategy for vibration reduction of vehicle seat suspensions. The VIVD device can control its inertance and damping by adjusting resistances in a variable admittance (VA) circuit different from the traditional mechanical damper. The circuit and mechanical dynamics model of the VIVD seat suspension is analyzed and verified with tests, and the energy storage characteristic and controllability of the VIVD device are explored. Also, the frequency response characteristics of the VIVD device are derived from the admittance characteristics of the VA circuit. For the semi-active VIVD seat suspension, an H controller is designed to obtain the desired control force. An ESPC strategy is proposed to make the electromagnetic force of the VIVD device track the desired control force. The test results show that the VIVD seat suspension can successfully suppress the seat's vibration, which is better than the traditional variable damping seat suspension performance. Under the random excitation, the root means square acceleration of the VIVD seat is reduced by 32.99% compared with a passive seat. This new semi-active VIVD device shows great potential in engineering applications.

To provide faster speed response, better current characteristics, more stable suspension, and stronger disturbance immunity for a bearingless induction motor (BIM) system, an enhanced linear active disturbance rejection control (ELADRC) strategy is proposed. Firstly, based on the air-gap flux oriented control, the speed LADRC and the suspension LADRC are respectively designed for the torque winding and suspension winding. The uncertainties and disturbance of the system are treated as a total disturbance in LADRC and linear extended state observer (LESO) is used to observe and compensate for it in real time. Secondly, by analyzing the defects of LADRC, the speed ELADRC and the suspension ELADRC with cascaded LESO are designed based on LADRC to improve the stability and disturbance immunity. Thirdly, the stability and the tracking performance of the second-order ELADRC are analyzed. Finally, simulation and experimental comparisons of the PID control strategy, the LADRC strategy and the ELADRC strategy are carried out. The analysis and results show that the proposed strategy not merely has good speed response and current characteristics, and lowers the influence of load disturbance, but also realizes the fast and stable suspension of the rotor and improves the anti-disturbance performance of the suspension system.

The electromagnetic suspension system (EMSS) plays a critical role in providing attractive force for middle-low-speed maglev trains, which contains two critical components– an electromagnet and a steel track. However, with the acceleration of trains, the eddy current generated by the relative motion between the electromagnet and the track becomes intensified, which may directly weaken the attractive force. To maintain the suspension airgap between the iron yoke and the track stable, more current needs to be inserted into the winding of the electromagnet. The local thermal surge existing in the winding may appear due to the overloaded input current for long term, which may cause the insulation aging or even damage of the winding. If the short circuit accident occurs between the neighboring turns of the winding due to the inter-turn insulating damage of the winding, the loss of suspension force tends to be deteriorated undoubtedly. In this paper, a novel hybrid suspension system mixed electromagnetic and permanent magnetic modes is proposed for enhancing suspension force with economical power consumption. But, when applying permanent magnets for assisting electromagnets, the firm absorption (FA) phenomenon needs to be considered. Two suspension schemes with unequal-width and unequal-height iron yokes are launched for reducing FA risk. The corresponding FEM models have been built and verified by experimental results. The comparison of different suspension schemes under dynamic condition with different relative velocity between the suspension module and the track has been undertaken in the end.

We will practice spread plating and pour plating using 10- or 100-fold dilution technique to enumerate bacteria cells in solutions on agars.

Al2O3 coatings were prepared by atmospheric plasma spraying (APS) and suspension plasma spraying (SPS). The microstructure, phase composition and nano-hardness of the two coatings were tested. Meanwhile, the friction and wear performance of SPS and APS in different environments were systematically studied. The results showed that both coatings exhibited a stable friction state and low wear rate under different environments. The special fine structure and high hardness value of SPS coating made its wear resistance much higher than that of APS coating. Additionally, the wear mechanisms of the two coatings in dry sliding friction were mainly abrasive wear, fatigue wear and adhesive wear. The APS coating had slight abrasion, while the SPS coating exhibited a negative abrasion state, in the seawater environment.

The goal of the research was to investigate the profile control and oil displacement characteristics of the polymer nanoparticles after high temperature swelling. The displacement parameters showed considerable influence on the plugging effect of the high-temperature swelled polymer nanoparticles, such as the core permeability, concentration of nanoparticles in the suspension, swelling time and swelling temperature, which makes it flexible to control the plugging effect by controlling displacement experiments conditions. Experimental results show that polymer nanoparticles dispersion system with a concentration of 500 mg/L is suitable for cores plugging with a permeability of 30 × 10−3 - 150 × 10−3 μm2, even after aging at 150 °C for three months. The shunt flow experiments show that when the displacement factors are optimal values, the polymer nanoparticles after high temperature swelling to plug the high-permeability layer selectivity and almost do not clog the low-permeability layer. Oil recovery of homogeneous artificial core displacement experiment and a heterogeneous double-tube cores model are increased by 20% and 10.4% on the basis of water flooding. The polymer nanoparticles can be a great help for petroleum engineers to better apply this deep profile control and flooding technology.

Digital light processing (DLP) is one of the most important additive manufacture technologies to fabricate ceramic parts with complex geometries. Compared with pure photosensitive resin, the cure performance of ceramic suspensions is obviously different due to the optical property change after the addition of ceramic powders. In this paper, a unique oxidation process was used to modify the optical properties of nitride powders including AlN and Si3N4. The properties of oxidized ceramics were investigated and the cure performance of ceramic suspensions was then characterized. The effect of oxidation time on cure performance was evaluated. The results showed that for AlN, oxidation process leads to the smaller cure depth and smaller excess cure width as compared with non-oxidized AlN and for Si3N4, oxidation process leads to the larger cure depth and larger excess cure width as compared with non-oxidized Si3N4, indicating that both refractive index and light absorbance of ceramic powders have obvious effects on cure behaviors. Additionally, the cure behavior of oxidized ceramic suspension in this study shows that the relationship of cure depth vs. incident energy agrees well with Beer- Lambert model, but the excess cure width vs. incident energy is not consistent with quasi Beer-Lambert model due to the nature of digital micromirror device (DMD).

Overhead conductors for transmission lines are subjected to cyclic loading due to Aeolian vibration which can lead to the failure of their wires. One of the most critical transmission power line points where fatigue failure occurs is the vicinity of the assembly consisting of the conductor and the suspension clamp. This work evaluates the fatigue life of assemblies made by two types of conductors, i.e. All Aluminium Alloy Conductor (AAAC) 1120 and 6201. Furthermore, metallic and elastomeric clamps are examined. Based on the generated S-N and fymax-N graphs, it was proved that the assembly AAAC 1120 with elastomeric clamp presented a better fatigue performance than the other three assemblies. Additionally, the change in fatigue life was investigated, failure and contact marks analyses were also performed on all samples after fatigue test with respect to the conductor layer where the failure occurred as well as the types of break and the position of wires break (whether radial and longitudinal position).

By surface modification with APTMS, spontaneous coagulation casting (SCC) of fused silica based on Isobam was achieved and the possible coagulation and molding mechanism is proposed. Through the interaction between the polar groups on the Isobam molecular chain and the incorporated –NH2 groups on the surface of the silica particles, Isobam molecular chains were adsorbed on the surface of particles, which initiate the formation of flocs and the solidification of the suspension. The addition of dispersant TMAH results in the hydrolyzation of Isobam, forming more –COO–, which effectively improves the fluidity and stability of the suspension. Then the zeta potential, rheological properties and coagulation behavior of the suspension were systematically investigated and the fused silica suspension with high solid content (up to 52 vol%), low viscosity and good coagulation properties were prepared at 1.8 wt% TMAH and 0.5 wt% Isobam dosage. After sintering at 1260 °C for 4 hours, the fused silica ceramics (50 vol% solid content) shows a high bending strength of 61.59 MPa, the lowest dielectric loss tanδ of 8.46 × 10-4 and the dielectric constant of 3.72. Thus, this work provides a simple and effective method for preparing fused silica and other ceramics with negative surface charge by Isobam SCC.

This paper presents a literature review on the use of sports suspension systems in the rehabilitation process. Suspension therapy, or sling-therapy, is a method of physical rehabilitation with the use of various systems of the suspension of the whole body or limbs. These systems are now widely used in rehabilitation treatment as well as in the training process. The possible modification of the sports suspension systems lays in the use of elastic suspensions. The use of elastic suspensions in sports variants of suspension systems can identify the weak link in the musculoskeletal chain and correct it, using a variety of dynamic exercises. Thus, the use of elastic suspensions makes it possible to strengthen the weaker muscle groups, by alternating performance of dynamic and static exercises. In this case the doctor is able to prevent participation of other, stronger muscle groups, in the motion. An involvement of compensatory muscle in movement is a signal to finish or change the conditions of exercise. By this way it is possible to form and train the right motor pattern in a patient without much effort. The use of elastic suspension makes it possible to increase or decrease the load without changing the number of repetitions of exercises and, accordingly, without changing the duration of sessions., В работе представлен обзор литературы, посвященной использованию спортивных подвесных систем в реабилитационном процессе. Подвесная терапия, или cлинг-терапия, — это метод физической реабилитации с использованием разнообразных систем подвеса всего тела или конечностей. Эти системы в настоящее время широко используются как в восстановительном лечении, так и в тренировочном процессе. Обсуждается возможное модифицирование спортивных подвесных систем путем использования эластичных подвесов. Применение эластичных подвесов в спортивных вариантах подвесных систем позволяет не только выявить слабое звено в скелетно-мышечной цепи, но и откорректировать его, используя разнообразные динамические упражнения. Так, использование эластичных подвесов дает возможность активизировать более слабые мышечные группы, чередуя выполнение динамических и статических упражнений. При этом врач имеет возможность проследить за тем, чтобы в выполнении движения не участвовали другие, более сильные мышечные группы. Включение в выполнение движения компенсаторных мышц является сигналом к завершению или изменению условий выполнения упражнений. Таким способом возможно сформировать и натренировать правильный двигательный паттерн у пациента, не прилагая больших усилий. Применение эластичных подвесов дает возможность увеличивать или уменьшать нагрузку, не изменяя количество повторений упражнения и, соответственно, не изменяя длительность занятия., У роботі представлений огляд літератури, присвяченої використанню спортивних підвісних систем у реабілітаційному процесі. Підвісна терапія, або cлінг-терапія, — це метод фізичної реабілітації з використанням різноманітних систем підвісу всього тіла або кінцівок. Ці системи сьогодні широко використовуються як у відновному лікуванні, так і в тренувальному процесі. Обговорюється можливе модифікування спортивних підвісних систем шляхом використання еластичних підвісів. Застосування еластичних підвісів у спортивних варіантах підвісних систем дозволяє не тільки виявити слабку ланку скелетно-м’язового ланцюга, але й відкоригувати його, використовуючи різноманітні динамічні вправи. Так, використання еластичних підвісів дає можливість активізувати слабші м’язові групи, чергуючи виконання динамічних і статичних вправ. До того ж лікар має можливість простежити за тим, щоб у виконанні руху не брали участь інші, більш сильні м’язові групи. Включення у виконання руху компенсаторних м’язів є сигналом до завершення або зміни умов виконання вправ. Таким способом можна сформувати і натренувати правильний руховий патерн у пацієнта, не докладаючи значних зусиль. Застосування еластичних джгутів дає можливість збільшувати або зменшувати навантаження, не змінюючи кількість повторень вправи і, відповідно, не змінюючи тривалість заняття.

BACKGROUND: Recent clinical studies have revealed the advantages of using suspension devices. Although the supine, lateral, and forward leaning bridge exercises are low-intensity exercises with suspension devices, there is a lack of studies directly comparing exercise progression by measuring muscular activity and subjective difficulty. OBJECTIVE: To identify how the variations in the bridge exercise affects trunk muscle activity, the present study investigated changes in neuromuscular activation during low-intensity bridge exercises. We furthermore explored whether the height of the suspension point affects muscle activation and subjective difficulty. METHODS: Nineteen asymptomatic male participants were included. Three bridge exercise positions, supine bridge (SB), lateral bridge (LB), forward leaning (FL), and two exercise angles (15 and 30 degrees) were administered, thereby comparing six bridge exercise conditions with suspension devices. Surface electromyography and subjective difficulty data were collected. RESULTS: The rectus abdominis activity was significantly higher with the LB and FL exercises compared with the SB exercise (p< 0.05). The erector spinae muscle activity was significantly higher with the SB and LB exercises, compared with the FL exercise (p< 0.05). The LB exercise significantly increased the internal oblique muscle activity, compared with other exercise variations (p< 0.05). The inclination angle of the exercise only affected the internal oblique muscle and subjective difficulty, which were significantly higher at 30 degrees compared with 15 degrees (p< 0.05). CONCLUSIONS: Relatively higher inclination angle was not effective in overall activation of the trunk muscles; however, different bridge-type exercises could selectively activate the trunk muscles. The LB and SB exercises could be good options for stimulating the internal oblique abdominis, and the erector spinae muscle, while the FL exercise could minimize the erector spinae activity and activate the abdominal muscles.

Purpose: The objective was to measure the intraoperative load tolerance of the thumb carpometacarpal (CMC) joint after trapeziectomy, tendon suspension, and interposition. Methods: In this single-center prospective study, preoperative pinch grip, thumb mobility, and hypermobility of the thumb CMC joint were determined by 2 hand surgeons. Patients completed the brief Michigan Hand Outcomes Questionnaire. During surgery and upon removal of the trapezium, the surgeon subjectively rated the degree of thumb CMC load tolerance as “stable,” “medium stable,” or “unstable.” A measurement system with an integrated force sensor was used to measure intraoperative thumb CMC load tolerance. The thumb ray was displaced manually by 10 mm toward the scaphoid, and the counteracting force was measured over the entire displacement. The objective load tolerance was determined as the maximal measured force after trapezium resection, tendon suspension, and interposition. Analysis of variance was used to test for the differences in load tolerance between the surgical steps. Spearman's coefficient was used to find correlations between load tolerance and clinical or patient-reported variables. Results: Twenty-nine patients with a mean age of 70 years (SD, 8.1 years) were available for analysis. The measured intraoperative load tolerance after trapeziectomy was 15.5 N (SD, 5.4 N) and significantly increased to 18.7 N (SD, 5.5 N) after suspension. Load tolerance only slightly increased after tendon interposition, increasing the force to 20.3 N (SD, 6.7 N). Neither the surgeon's subjective stability rating nor the clinical or patient-reported variables correlated with the measured load tolerance after trapeziectomy. Conclusions: Our results show that tendon suspension leads to the highest increase in thumb CMC load tolerance during resection-suspension-interposition arthroplasty. Clinical relevance: Tendon suspension appears to be the most important step in stabilizing the metacarpal base after trapeziectomy, whereas tendon interposition does not seem to have a relevant additional effect regarding load tolerance, at least immediately after surgery., Journal of Hand Surgery Global Online, 4 (1), ISSN:2589-5141

Erosion may be defined as the destruction of a material by abrasive action of a liquid or gas. The wearing away is purely mechanical with no electro-chemical reaction. This process occurs on surfaces, pipelines wherever the flow of liquid along with particles in suspension causes erosion. In this investigation, the erosion rate on a coated surface was studied using pot erosion tester. The substrate material used was stainless steel of grade 316. The material was machined to the required dimensions and was coated one set with tungsten carbide- cobalt and another set with alumina. The coating was done using a detonation spray process. The specimens were weighed before and after the testing. The mass loss and erosion wear rate were calculated. It was found that the erosion wear rate was minimum when the speed of rotation was 3 m/ sec and increases as the speed increases. The SEM examination revealed the formation of flake type debris due to the interaction between the erodent and the specimen.

Owing to the unique advantages in flight altitude, dwelling time and wide coverage area, stratospheric airships provide permanent monitoring and surveillance for both civil and military applications. Here we propose a semi-rigid stratosphere airship design with circumferential high-pressure inflatable rings and a longitudinal carbon fiber skeleton supported inside. We perform numerical simulations to analyze the deformation characteristics during the whole ascending and descending process. An equivalent internal gradient pressure model of helium is established based on the capsule shape and buoyancy-weight equilibrium conditions. The implicit dynamic method is used to deal with the large deformation of the airship capsule under a low negative pressure condition. Deformation and load-bearing performance of the airship capsule, inflatable ring, skeleton, and suspension line are obtained under different working conditions. The results show that the airship, supported with the inflatable rings and the suspension lines, effectively maintains the shape and ensures the stiffness during the ascending, dwelling, and descending stages, especially suffering from negative pressure.

The main function of active suspension systems is to suppress vibration resulted from the road roughness and improve passengers' ride comfort, and some time-domain constraints such as mechanical limitation should be taken into consideration when designing active controllers. In this article, a constrained adaptive backstepping control scheme is proposed for the quarter-car suspension with parameter uncertainties, in which the primary control objective is to stabilize the vertical motion of the vehicle body and the suspension mechanical structure constraint can be satisfied in the meanwhile, and energy analysis has been made to demonstrate the potential of energy regeneration and reducing energy consumption for the designed active suspension system. In terms of dealing with the hard constraint, a specific nonlinear filter is employed in order to integrate the main control objective and time-domain constraint into a single controlled variable. In addition, a barrier Lyapunov function is selected to make the defined controlled variable converge to zero and stay in the allowable limit, which means that the vertical motion of the vehicle body can be stabilized and the suspension deflection restriction will not be transgressed. Experiments are carried out on the active suspension test plant to verify the effectiveness of the designed control scheme. Since the high energy consumption of active actuators is one of the drawbacks to be overcome, the energy flow of the dc motors is analyzed in the latter part of this article so as to provide a theoretical basis for energy harvesting design in further study. Finally, the energy consumption of the active suspension plant in experiments is figured out and its potential of energy recovery is demonstrated in detail.

In this study, we have carried out experiments to characterize the wall slip of colloidal suspensions of kaolinites. To demonstrate slip, the rheological measurements were carried out with parallel-plate geometry with smooth and rough plates. The asperities of the rough surface penetrated the slip layer and created a nearly no-slip region, whereas the smooth plate showed significantly higher slip, a conclusion drawn by comparing the macroscopic flow curves in both cases. Two slip regimes were identified, namely, (i) an elastic slip regime below the yield stress of the suspension where the material slips like a solid and (ii) a slip regime above the yield stress where the material yields and flows. The slip velocity was quantified using a simple phenomenological slip model that seems to capture slip in both flow regimes. The transition from the first slip regime to the other has been resolved numerically as the material starts yielding first at the edge of the parallel-plate geometry with the yield point propagating inwards as the rotational speed is increased. The numerical method also establishes uniquely the yield stress value, which was found to agree with data obtained from parallel-plate, cone-and-plate, and concentric cylinder geometries.

The optimum design of a passive vehicle suspension system is an important task to enhance riding performance. The passive suspension system is the most reliable system and cheapest. In this work, the Harris Hawk Optimization (HHO) algorithm was used to optimize the design of a passive vehicle suspension system. HHO was chosen due to its efficient exploration which increases the diversity of the released solutions and the various exploitation schemes which enhance the best-explored solutions. A novel scaled multi-objective function is developed which combines different objectives such as road holding and ride comfort which wasn’t be included in the previous work. Two vehicle models are used in the test are quarter and half vehicle model. The performance of the optimized HHO passive suspension system is compared to that in the literature work such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and Fire-Fly Optimization algorithm (FA) optimized systems in addition to the traditional passive suspension system. The experimental results show the superiority of HHO over other algorithms in the literature in terms of quality of solution and robustness for the optimum design of the suspension system’s parameters. The peak value of the body acceleration of the HHO optimized suspension model is decreased by about 16.5% than the original passive quarter vehicle model. The dynamic tire load of the HHO optimized suspension system was enhanced by more than 7%. Besides, the peak value of body displacement is decreased by more than 25% from 4.6 cm for the traditional passive suspension system to 3.5 cm for the optimized HHO system.

In this paper, the pressure drop influencing parameters in slurry pipeline have been optimized by using Taguchi’s approach. S/N ratios were calculated by orthogonal array L16 (42) and characterized by using smaller-the-better rule. Pressure drop experimental were conducted on pilot plant test loop having 50 mm diameter. Pressure drop of fly ash slurry was measured with addition of coarser bottom ash at different solid concentrations and flow velocities. The bottom ash addition reduced the pressure drop of fly ash slurry in pipeline and pressure drop increases with the increase in the flow velocity. Flow velocity is the most influencing parameter as compare to the other parameters. The rheological charactertrics of fly ash slurry is also studied with and without addition of bottom ash in order to transport the high solid concentration of fly ash slurry in a pipeline. Apparent viscosity of fly ash slurry suspension with 10, 20 and 30% addition of bottom ash indicates that apparent viscosity of fly ash slurry decreases with the addition of bottom ash due to the presence of coarser bottom ash in fly ash finer particle suspension. The apparent viscosity plays a vibrant role on pressure characteristics of fly ash slurry transportation.

With the development of MEMS technologies, research on MEMS gas sensor has emerged recently, and micro hotplate (MHP) is designed to provide suitable temperature for MEMS gas sensor. Heat properties of MHP profoundly influences the sensing properties of MEMS gas sensor. With the tendency of down-sizing in MEMS gas sensors, traditional temperature measurements such as contact measure and infrared temperature detection are no longer available due to relatively low resolution. In this work we used finite element analysis (FEA) to realize cost- and time-saving heat property evaluations for MEMS gas sensor with different MHP structures, and two indexes were introduced to describe heat properties of MHPs, such as area factor Q to describe area of isotherm and roundness of isotherm %R to evaluate isotherm shape. It is found that silicon oxide and silicon nitride suspension structures have different tendency in heat properties. The size of working area has important impacts on the heat properties of the MHP, and MHP with different working area may be applied in different applications. For instance, larger MHP with 1643 μm2/K area factor Q is suitable for noble metal catalytic gas sensing application, which requires uniform temperature distribution, and smaller MHP, which could reach 609 °C peak temperature at 30 mW power-consumption, is applied to IoT applications with battery power supply. Furthermore, some special characteristics of the heat distribution of MHP are found with adjusting the width of suspension beams. This work provides guidance on how to design proper sensing material shapes to utilize the performance of MHP and reduce heat loss.

Porous materials manufactured by freeze-casting are demonstrating potential application as oxygen carriers for the production and purification of hydrogen, or anode material for lithium-ion batteries. However, to obtain the required pore morphology and sufficient mechanical strength, the suspension processing parameters must be controlled. Fe2O3 nanoparticles/camphene suspensions were fabricated using stearic acid as the dispersant agent showing a low-viscosity (130 mPa·s) with a high solid volume fraction (0.3). Suspensions show a shear-thinning behavior according to the Sisko model and a maximum packing fraction of 0.569 estimated from a zero porosity sample. A modified Krieger and Dougherty model was introduced to incorporate the influence of the particle-aspect ratio. The Fe2O3 scaffolds manufactured by freeze-casting shown a gradient pore size along the freezing direction, which was diminished with the solid volume fraction, the compression strength was improved with the pore size reduction and fitted according to the minimum solid area model.

Carbon nanotubes (CNTs) have exhibited immense potential for applications in biology and medicine, and once their intended purpose is fulfilled, the elimination of residual CNTs is essential to avoid negative effects. In this study, we demonstrated the effective collection and simple removal of CNTs dispersed in a suspension via thermal convection. First, a tapered fiber tip with a cone angle and end diameter of 10° and 3 μm, respectively, was fabricated via a heating and pulling method. Further, a laser beam with a power and wavelength of 100 mW and 1.55 μm, respectively, was launched into the tapered fiber tip, which was placed in a CNT suspension, resulting in the formation of a microbubble on the fiber tip. The temperature gradient on the microbubble and suspension surface induced thermal convection in the suspension, which resulted in the accumulation of CNTs on the fiber tip. The experimentally formed CNT cluster possessed a circular top surface with a diameter of 87 μm and an arched cross-section with a height of 19 μm. Furthermore, this CNT cluster was firmly attached to the fiber tip. Therefore, the removal of CNT clusters can be realized by simply removing the fiber tip from the suspension. Moreover, we simulated the thermal convection that caused CNT aggregation. The obtained results indicate that convection near the fiber tip flows toward it, which pushes the CNTs toward the fiber tip and enables their attachment to it. Further, the flow velocity is symmetrically distributed as a Gaussian function, which results in the formation of a circular top surface and arched cross-sectional profile for the CNT cluster. Our method may be applied in biomedicine for the collection and removal of nano-drug residues.

This study involves the development of a Suspension system for FSAE vehicles participating in the Combustion Category. The front setup is also introduced with a bar-type Anti-Roll Bar (ARB) to manipulate the Understeer and Oversteer response of the vehicle. The initial parametric study was performed with an iterative approach in the spreadsheet. Race-cars also have stiffer suspension i.e.; the ride frequency is above 2 Hz; the reason being that the driver does strict maneuvering on the race track. FSAE vehicles have ARB's for better cornering performance and to manipulate the response of the vehicle mainly understeer and oversteer suiting to the driver. Another advantage is the limitation of camber gain caused by the body roll as it improves the traction. Further, the Kinematic study of all the components in the system was analyzed through IPG Kinematic Software. The focus was made on the variation of Camber Angle, Steer Angle, Track Change, and Roll Angle with and without the ARB incorporation. The calculation for the selection of different bearings is also performed. Considering the previous vehicles and the new design goals, parametrizing of the vehicle is also performed. The overhang of the vehicle plays an important factor in the longitudinal load transfer during the braking and acceleration. Forces experienced by all the components were also extracted from the software. This data is then used as the input parameter for Structural Simulation on CAE platform ANSYS. Material properties of Aluminum 6061 T-6 are used for the Bell Cranks and carbon Steel is used for ARB setup. Static structural simulation is performed on the Front Rocker, Upright and Hub. Specific torsional simulation is done on the ARB considering the axial offset position of the support bearing and the loading point on the blade.

In this paper, we investigate the movement of an inverted pendulum, the suspension point of which performs high-frequency oscillations along a line making a small angle with the vertical. We prove that under certain conditions on the function describing the oscillations of the suspension point of the pendulum, a periodic motion of the pendulum arises, and it is asymptotically stable.

In this manuscript, peristaltic transport induced by a sinusoidal traveling wave in the case for a viscous incompressible Newtonian fluid mixed with rigid spherical particles in the presence of a flexible inner tube, where the inner tube is also moving with a sinusoidal traveling wave of moderate amplitude is studied. The governing equations of the mixture (fluid-particle suspension) are written in two-dimensional cylindrical coordinates. The long-wavelength approximation is used to simplify the system of equations (d<

Functionally graded materials (FGMs) play an essential role in tissue engineering because of their satisfactory histocompatibility and excellent mechanical performance. While traditional manufacturing methods allow production of simple FGMs, precise control of composition and customized property at transition between the dissimilar materials is still a challenge. Here, an extrusion-based functionally graded additive manufacturing (FGAM) platform was developed to generate smooth graded parts by thrusting out monolithic cylindrical filaments with high viscosity. Furthermore, the rheological properties, hydrodynamic behavior, and mixed homogeneity of the non-Newtonian fluids were studied. Therefore, the appropriate solid contents, alternative energy-efficient mixers, and optimized printing parameters were proved to be beneficial for an outstanding deposition effect of the suspension. Ultimately, an object with smooth gradient was successfully manufactured. The validity of this strategy was verified via optical microscopy combined with an image processing method to gauge homogeneity and a scanning electron microscope to investigate graded composition and microstructure.

The aim of this work is to design a variable universe fuzzy control of a wheel loader semi-active cab suspension with damping multimode switching shock absorber. Considering the cost and reliability, a new type of shock absorber, whose adjustable damping characteristics are achieved by just changing the on–off statuses of two solenoid valves, is applied to the wheel loader cab suspension. The vibration model of the wheel loader, which considers the vibration characteristics of the working device, the four-wheel correlated random road excitation, and the engine vibration excitation simultaneously, is established first. Based on the working principle of the target shock absorber, the damping multi-state switching model is also established to reflect the relationship between the damping coefficients and the on–off statuses of two solenoid valves. Then, a variable universe fuzzy damping control strategy, which can determine the optimal switching sequences of the damping modes according to the cab suspension performance indexes, is designed. Finally, simulation analyses were conducted to verify the effectiveness of the proposed control approach of the wheel loader semi-active cab suspension with multimode switching shock absorber.

Microfluidic devices with superior microscale fluid manipulation ability and large integration flexibility offer great advantages of high throughput, parallelisation and multifunctional automation. Such features have been extensively utilised to facilitate cell culture processes such as cell capturing and culturing under controllable and monitored conditions for cell‐based assays. Incorporating functional components and microfabricated configurations offered different levels of fluid control and cell manipulation strategies to meet diverse culture demands. This review will discuss the advances of single‐phase flow and droplet‐based integrated microfluidic suspension cell culture systems and their applications for accelerated bioprocess development, high‐throughput cell selection, drug screening and scientific research to insight cell biology. Challenges and future prospects for this dynamically developing field are also highlighted.

The failure of the inverter bridge arm or the open circuit of the phase winding may occur during the operation of a combined winding bearingless flux-switching motor, causing both of the rotor rotation and suspension to malfunction, hence fault-tolerant control is vital for the motor's reliability and stability. In this paper, a fault-tolerant operation control strategy for combined winding bearingless flux-switching permanent magnet motors under open-circuit fault condition is proposed. Firstly, how to control the electromagnetic torque and suspension force acting on the rotor with the combined winding structure is explained, and then the mathematical models of the torque and suspension force which can be controlled individually by different current components are deduced in detail. Afterward, the relation of the phase current without and with winding fault is discussed, and the operation conditions of maintaining constant torque and suspension force after fault are demonstrated. Whereupon, the fault-tolerant control block diagram is constructed. Finally, the experimental results are presented to demonstrate the performance of the proposed strategy.

The Humber Bridge is an iconic Grade 1 listed structure, which remains one of the longest single-span suspension bridges in the world. It has a main span of 1410 m and a total span length of 2220 m. The bridge deck is connected to the main suspension cables by spiral wire rope hangers with socketed end connections. In this paper, the global analysis of the bridge is discussed to identify the predicted stresses in the hangers, which was complicated by the triangulation of the hangers. The paper then covers the selection of three trial hangers to be replaced, the specification of the replacement hangers and the testing specified to determine the residual life of the original hangers. The design, fabrication and installation of the works involved in replacing the hangers is described and the paper concludes with a discussion of the results of the hanger testing and how this has informed the strategy for management of the remaining hangers.

In order to develop a highly efficient, simple-preparation and renewable explosion suppressant of composite powders, the superfine NaHCO3-shell powder (S-S) composite explosion suppressant was prepared by one-step method with airflow crusher to fulfill the mechanical dry coating of shell powder by NaHCO3, which solved the contradiction between dispersion and suspension force of explosion suppressant particles. The composition optimization and performance test of S-S composite explosion suppressant were carried out with the use of 20 L explosion tank and large tubular coal dust characteristics identification instrument. The results show that when the shell powder particles are coated with NaHCO3, the overall water absorption performance of the powder is reduced, the particle agglomeration phenomenon is weakened, and the dispersion is obviously improved. With the increase of NaHCO3 ratio, the ignition sensitivity of coal dust decreases, and the time to reach the first explosion Pmax is gradually delayed, and both Pmax and (dP/dt)max decrease. With the following explanations: NaHCO3 has a significant effect on reducing (dP/dt)max due to its chemical reaction, while shell powder is beneficial to reducing the Pmax due to its physical barrier effect. The suppression effect of S-S composite explosion suppressant on coal dust explosion is far better than that of pure NaHCO3 or shell powder.

A unique adaptive neural network control scheme is proposed for active suspension systems by employing bioinspired nonlinear dynamics, so as to address several critical engineering issues including energy efficiency, input delay, and unknown/uncertain dynamics simultaneously. A novel constructive predictor is firstly designed to solve the effect of input delay. Neural networks are then adopted to approximate the uncertain/unknown dynamics, and importantly, a unique finite-time adaptive control is established which can not only online update the input and output weights of the neural networks but also intentionally introduce beneficial nonlinear dynamics to vibration control. The significant difference from most existing controllers lies in that the designed controller can effectively utilize beneficial nonlinear stiffness and damping characteristics of a novel bioinspired reference model and, thus, purposely achieve superior vibration suppression and obvious energy-saving performance simultaneously. Theoretical analysis and experimental results vindicate that the proposed controller can effectively suppress vibration with much more improved control performance and considerably reduced control energy consumption more than 44%. This should be for the first time to reveal both in theory and experiments that a superior suspension performance is achieved simultaneously with an obvious control energy saving, by employing beneficial bioinspired nonlinear dynamics, compared to most traditional control methods.

Proppant is a key material for enhancing unconventional oil and gas production which requires a long distance of migration and efficient liquid conductivity paths within the hydraulic fracture. However, it is difficult to find a proppant with both high self-suspension ability and liquid conductivity. Here, a simple method is developed to coat epoxy resin onto the ceramic proppant and fabricate a novel coated proppant with high hydrophobicity, self-suspension, and liquid conductivity performance. Compared with uncoated ceramic proppants, the epoxy resin coated (ERC) proppant has a high self-suspension ability nearly 16 times that of the uncoated proppants. Besides, the hydrophobic property and the liquid conductivity of the ERC proppant increased by 83.8% and 16.71%, respectively, compared with the uncoated proppants. In summary, this novel ERC proppant provides new insights into the design of functional proppants, which are expected to be applied to oil and gas production.

Ever since Beijing has sought to fuel domestic growth through Chinese-led development overseas—first under the aegis of Jiang Zemin's Going Out Policy and more recently as part of Xi Jinping's Belt and Road Initiative— thousands of Chinese have moved overseas for work. Africa has been one of the destinations of Chinese companies and their expatriate staff. Although we have learned a great deal about China's mega-projects across the African continent, little is known about the certified engineers and experienced builders who carry them out. What brings them to Africa? And, more importantly, what makes them stay for years on end, even if they wish to return to China? In this article I zoom in on the lives of Chinese men employed in Ethiopia's construction industry to show how three decades of domestic growth in China has pushed workers overseas, while jeopardizing their return. Workers' lives are marked by double displacement. They are not only isolated from local African communities through a dormitory labour regime that controls their time and limits their mobility, but also, more importantly, they are displaced from social life in China. Domestic development has at once increased aspirations and made them harder to obtain, especially for men, who are expected to fulfill the promise of upward social mobility for themselves and their families. In order to realize aspirations and meet social expectations related to social reproduction, geographic mobility has become a necessity for men who cannot rely on family wealth or connections, forcing them into a state of suspension.

Effective methods for rapid sorting of cells according to their viability are critical in T-cells based therapies to prevent any risk to patients. In this context, we present a novel microfluidic device that continuously separates viable and non-viable T-cells according to their dielectric properties. A dielectrophoresis (DEP) force is generated by an array of castellated microelectrodes embedded into a microfluidic channel with a single inlet and two outlets; cells subjected to positive DEP forces are drawn towards the electrodes array and leave from the top outlet, those subjected to negative DEP forces are repelled away from the electrodes and leave from the bottom outlet. Computational fluid dynamics is used to predict the device separation efficacy, according to the applied alternative current (AC) frequency, at which the cells move from/to a negative/positive DEP region and the ionic strength of thesuspension medium. The model is used to support the design of the operational conditions, confirming a separation efficiency, in terms of purity, of 96% under an applied AC frequency of 1.5 × 106 Hz and a flow rate of 20 µl/h. This work represents the first example of effective continuous sorting of viable and non-viable human T-cells in a single-inlet microfluidic chip, paving the way for lab-on-a-chip applications at the point of need.