Components Of Suspension Research Articles

Simulation and experiment of the magnetorheological seat suspension with a seated occupant in both shock and vibration occasions

The aim of the present work is to develop an magnetorheological (MR) seat suspension for military vehicles to mitigate dynamic responses of seated occupant in both shock and vibration occasions. The main components of the MR seat suspension are tested and modelled. Subsequently, a mathematical model incorporating the MR seat and a seated occupant is established. The vibration and shock simulations based on the established model are carried out, and the results indicate that the proposed MR seat suspension can significantly alleviate the acceleration responses of the seated occupant under vibration input, and simultaneously possess the ability of reducing the spinal injury risk in the presence of severe impact. The systematic experiments of the MR seat prototype with a 50th percentile male hybrid III dummy are conducted, it is found out that the experimental results are in good agreement with the theoretical simulation results, which demonstrates that the developed MR seat suspension is provided with favourable vibration reduction performance and impact resistance.

Dynamic modeling and adjustable damping layered control of air suspension hybrid system

ABSTRACT Due to the coupling of continuous variables and discrete events, the vehicle height adjustment and damping force control system of air suspension can be described as a typical hybrid system, which poses theoretical challenges for researchers in recent years. Therefore, this paper focuses on the modelling and control of the air suspension hybrid system, realising the coordination control between the solenoid valve on-off status and the magneto-rheological damper current. A highly nonlinear hybrid dynamical mechanism model of vehicle height and damping force adjustment is established to describe the continuous dynamic behaviour and the discrete events of air suspension. Based on some assumptions and piecewise linear approximation for nonlinear components of air suspension, the mixed logical dynamical model compiled by the hybrid systems description language is constructed by introducing the auxiliary logical variables and the continuous logical variables. Using this model, a novel layered control strategy is designed and the efficient is verified by test results.The simulation results show that the proposed control method can not only adjust the vehicle height without switching the solenoid valve frequently,but also improve the ride comfort without deteriorating the handling stability, which leads to the closed-loop system with a favourable dynamical property.

Experimental and numerical investigation on the components of a pantograph slider suspension

Mechanical properties of the components of a pantograph’s slider suspension system have large influence on the quality of pantograph-catenary interaction. In the paper the authors present the results of their experimental research on the springs that are used in the pantograph being currently in operation in Europe. Static and dynamic tests were performed, which were aimed at determining the stiffness and damping coefficients respectively. Subsequently, the procedure for automated numerical model building for the pantograph’s springs was prepared employing the Python programming language and the MSC Marc solver. When a spring model is build (accordingly to the geometric properties of the springs used in tests), the elaborated algorithm iteratively tunes the material properties and computes static and dynamic load-cases, making direct reference to the experimental procedure. After completing several iterations the numerical model is finally validated, and proper material properties, as the Young modulus and the coefficients of Rayleigh damping model, are found. Then, the obtained model can be used to determine the damping and stiffness coefficients for springs characterizing various diameters, wire diameters, numbers of turns, etc. The presented modelling tool is useful for determining the pantograph sliders suspension characteristics.

ЩОДО АНТРОПОГЕННОЇ СКЛАДОВОЇ РЕЧОВИНИ АТМОСФЕРНОГО АЕРОЗОЛЮ м. ЗАПОРІЖЖЯ

The article is devoted to the study of the influence of technogenic processes on the environment, in particular the determination of the contribution of a substance formed in the course of economic activity to the total composition of the solid component of atmospheric aerosol. The actual material was obtained on the basis of the system monitoring of surface air flows within such a powerful industrial center as Zaporizhzhia city. Samples of suspended atmospheric matter accumulated on the filter textile were taken monthly for two years. Parallel continuous observations of hydrometeorological factors (speed, direction, duration of winds, rainfall) provided an integrated approach to the development and synthesis of research results. Field observations and laboratory studies determined a number of patterns in the distribution of the sedimentation substance in the air and the interrelations of the anthropogenic and natural constituents of the substance. The publication describes the features of the chemical composition and morphology of detrital particles, the entry of which into the air caused by technogenic processes, as well as the condensation component of the aeolian suspension, the origin of which is associated with high-temperature processes. The changes in the ratio of the natural / anthropogenic components in the material composition of the aerosol under the influence of external factors (natural and anthropogenic) were investigated. These changes also affect the redistribution of quantitative ratios between the condensed and dispersed components of the aeolian suspension. At the same time, the detrital component can reach the aleuritic dimension, the iron content exceeds 90 %, and the proportion of impurities of a number of ferrous and heavy metals, in particular titanium, manganese, nickel, copper, lead, zinc can reach 40% or more. Heavy metals are also found in the form of separate detrital and condensation formations, where their content varies in the range of 50 – 70 %. Analysis of the condensation component in the aerosol samples for the period of the research allowed us to give a general characteristic of it and to carry out a preliminary classification by chemical composition. The possibility of determining the focus of atmospheric pollution in terms of the shape, chemical composition and size of aerosols, seasonal factors and characteristics of atmospheric flows were also outlined.

Study of the vibrational behaviour of the components of a car suspension

The paper presents a study of the vibrational behaviour of a car suspension in the frequency range from 50 to 200 Hz. The vehicle has a torsion spring suspension. The aim of the study is to provide a numerical approach, which evaluates the impact of the tyre vibration characteristics and the elastic properties of suspension elements on the vibrational behaviour of the “tyre-suspension-body” system. The object of the study are the elements of the suspension – stub-axle, upper and lower suspension arms, strut rod, torsion bar and others. The suspension is equipped with pneumatic tyres with different vibration characteristics. Laboratory experiments are done. The tyre contact patch is disturbed by harmonic force. The accelerations of the wheel axle and specific points of the suspension are obtained. A numerical model of the system is created by using the Finite Element Method available in SolidWorks Simulation software. The model allows to determinate the accelerations at different points of the suspension. The results of the experimental and theoretical studies are compared. The values obtained in the two studies are similar.

Quantitative Methods for Testing Antiviral Activities of Textile Fabrics

Objective: In recent years, antiviral products modified with various antiviral agents are now widely studied and developed. The establishment of appropriate antiviral testing methods for such products is necessary to discuss the efficiency of antiviral agents in the products. In this study, quantitative antiviral testing methods for textile fabrics were studied under several test conditions. Method: Influenza virus and feline calicivirus were used as model viruses. A cotton fabric and a 100% polyester fabric were used as control samples and Ag nanoparticles were used as model antiviral agents. In testing the antiviral performance of a product with an antiviral treatment, a virus suspension is inoculated onto the product and subsequently washed out of the products. The virus infectivity titer in the washed-out suspension is then measured. The viral infectivity titer of the test suspension was determined by counting the plaque-forming units (PFU). In estimating the antiviral activity of textile products, the components of the virus suspension, the contact time, and the contact temperature were chosen as study points. Results: The virus infectivity titer was significantly affected by experimental conditions such as the concentration of the medium of the virus suspension, the contact temperature, and the type of textile fabric support. To estimate the antiviral efficiency under stable conditions for viruses, a lower temperature and a lower Eagle’s minimal essential medium (EMEM) concentration appear to be appropriate. It was confirmed that Ag nanoparticles on textile fabrics have antiviral activity; however, this antiviral activity was suppressed in media of high concentrations. Conclusions: It was shown that inactivation of antiviral agent might be caused by components of the virus suspension, as well as by other experimental conditions. Furthermore, the viruses can be deactivated by contact with textile fabrics, even in the absence of antiviral agents. These findings indicate that the antiviral performance testing conditions must be carefully chosen with due consideration of the field of application.

Generalized Modelling of the Stabilizer Link and Static Simulation Using FEM

Abstract This paper proposes an organological approach of one of the components of front suspension, namely anti-roll power link. There will be realized a CAD 3D modelling of this power link. 3D modelling is generalized and there were used the powers of Catia V5R20 software. Parameterized approach provides a high flexibility in the design, meaning that dimensional and shape changes of the semi-power link are very easy to perform just by changing some parameters. Several new versions are proposed for the anti-roll power link body. At the end of the work, it is made a static analysis of the semi-power link model used in the suspension of vehicles OPEL ASTRA G, ZAFIRA, MERIVA, and constructive optimization of its body.

Leaching effect in gadolinia-doped ceria aqueous suspensions for ceramic processes

Abstract Gadolinium doped ceria (CGO) is a commonly used electrolytic material for Solid Oxide Fuel Cells (SOFCs) and for this reason different shaping methods for its deposition are reported in literature. Most of these processes are based on the use of organic-based CGO suspensions, but water-based processes are acquiring increasingly interest for their economical and environmental friendly properties. In this paper we reported how the components of water-based suspension and some unexpected process parameters can deeply affect the functional properties of the final powder. In particular, we observed that CGO powders are strongly affected by ionic leaching induced by furoic acid used as dispersant: the extent of this leaching was related to the dispersant concentration and suspension’s ball-milling-time; the phenomenon was confirmed by ICP-AES analyses on suspensions surnatant. Most importantly, ionic leaching affected the electrical properties of CGO: leached powder showed a higher ionic conductivity as a consequence of a partial removal of Gd ions at the grain boundaries. This work is therefore pointing out that when considering water-based suspensions, it is extremely important to carefully consider all the process parameters, including the organic components of the ceramic suspension, as these could lead to unexpected effects on the properties of the powder, affecting the performance of the final shaped material.

Effective electrostatic interactions among charged thermo-responsive microgels immersed in a simple electrolyte.

This work explores the nature and thermodynamic behavior of the effective electrostatic interactions among charged microgels immersed in a simple electrolyte, taking special interest in the effects due to the thermally induced variation of the microgel size while the remaining parameters (microgel charge and concentration, plus the amount of added salt) are kept constant. To this end, the rigorous approach obtained from applying the precise methodology of the dressed ion theory to the proper definition of the effective direct correlation functions, which emerge from tracing-out the degrees of freedom of the microscopic ions, is employed to provide an exact description of the parameters characterizing such interactions: screening length, effective permittivity, and renormalized charges. A model solution with three components is assumed: large permeable anionic spheres for the microgels, plus small charged hard spheres of equal size for the monovalent cations and anions. The two-body correlations among the components of this model suspension, used as the input for the determination of the effective interaction parameters, are here calculated by using the hyper-netted chain approximation. It is then found that at finite microgel concentrations the values of these parameters change as the microgel size increases, even though the ionic strength of the supporting electrolyte and the bare charge of the microgels remain fixed during this process. The variation of the screening length, as well as that of the effective permittivity, is rather small, but still interesting in view of the fact that the corresponding Debye length stays constant. The renormalized charges, in contrast, increase markedly as the microgels swell. The ratio of the renormalized charge to the corresponding analytic result obtained in the context of an extended linear response theory allows us to introduce an effective charge that accounts for the non-linear effects induced by the short-ranged association of microions to the microgels. The behavior of these effective charges as a function of the amount of added salt and the macroion charge, size, and concentration reveals the interplay among all these system parameters.

Finite Element Analysis on the Key Parts of Rubber Suspension

Rubber suspension system is a new suspension system in which rubber is used to be the elastic element, thus rubber spring is one of the key components of suspension. Based on its concrete structure, a finite element model of rubber spring is made and so as to analyze the rubber suspension forces under different working conditions, to analyze the strength and stiffness for providing a reference for the design.

Mechanical production of pellets for the application of entomopathogenic nematodes: factors that determine survival time of Steinernema glaseri

Applications of infective juveniles (IJ) of entomopathogenic nematodes (EPN) formulated in pellets are still limited. This is principally due to limited advances in the technology of formulation. We aimed to develop a new method of mechanical formulation through material flow and to analyse its effect on the survival time of encapsulated EPN by varying the granular materials, the components of the aqueous suspension, the age of the nematodes and by applying a surface coating (C) to the pellet. Three-day-old and two-month-old Steinernema glaseri IJ were encapsulated with different proportions of diatomaceous earth (DE) and attapulgite clay (AC). The aqueous suspension containing the nematodes was prepared with double distilled water (DDW), varying proportions of Opuntia ficus-indica mucilage (OM) or gelatin (GL), and a sunflower oil surface treatment. The pellets were stored at an average room temperature of 23 ± 6°C. The best results were obtained with the following proportions: 100DE:0AC and 50DE:50AC, using the OM suspension, three-day-old nematodes and a surface C, which resulted in an average of 14 days survival time. These results confirmed that the nematodes do not die during mechanical encapsulation and that the age of the IJ as well as the loss of moisture during storage at room temperature were the factors that decreased the survival of encapsulated EPN. It was concluded that it is necessary to use neonate IJ and to reduce the moisture transfer rate in the granular structure in order to delay the desiccation of the encapsulated nematodes.

Controllable Synthesis of ZnO with Various Morphologies by Hydrothermal Method

ZnO microstructures with various morphologies have been controllably synthesized by hydrothermal route using different precipitant and zinc source in liquid solution. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the ZnO2, Zn(OH)2 and ZnO structures to understand the role of precipitant and precursors in the growth of various morphologies. The nucleation and growth process can regulate by changing the precipitant. When H2O2 was used as precipitant, ZnO particles with a rather uniform particle size of -500 nm and a rather rough surface was obtained. While, ZnO synthesized in this polyvinyl pyrrolidone (PVP) solution has the same granular morphology with particle size of 300-1000 nm. In contrast, ZnO sunflower and polyhedron aggregates composed of several smaller polyhedron were formed, when ammonium hydroxide and NH4HCO3 was applied, respectively. Meanwhile, precursors play an important role in the determination of the morphology of ZnO. Sunflower and dumbbell like ZnO composed of nanosheets were obtained, when different centrifugal component of Zn(OH)2 suspension was applied as zinc source. In contrast, sunflower and dumbbell like ZnO composed of nanorods and ZnO rods were obtained, when different centrifugal components of ZnO2 suspension were used as zinc sources. The growth mechanism of ZnO nanostructures fabricated by the hydrothermal process using different zinc sources was tentatively investigated.

Fatigue behaviour and lifetime calculation of the cast irons EN-GJL-250, EN-GJS-600 and EN-GJV-400

The current paper focuses on the cast irons EN-GJL-250 (ASTM A48 35B), EN-GJS-600 (ASTM 80-55-06) and EN-GJV-400, which are often used as structural materials for internal combustion engines and components of the wheel suspension and in the wind energy industry, e.g. for rotor hubs. Light and scanning electron microscopic investigations were done to characterise the individual microstructure, e.g. different graphite precipitates, in particular lamellar graphite (EN-GJL-250), nodular graphite (EN-GJS-600) and compacted graphite (EN-GJV-400). In stress-controlled load increase and constant amplitude tests at ambient temperature, mechanical stress-strain hysteresis, temperature and electrical resistance measurements were performed to characterise the fatigue behaviour of the investigated materials. All measured data depend on microstructural changes due to plastic deformation processes in the bulk of the specimens and the interfaces between matrix and graphite. This data represent the actual fatigue state. The cyclic deformation behaviour is dominated by cyclic hardening processes and graphite-matrix debonding.The physically based fatigue life calculation method “PHYBAL” was modified to the specific requirements of more inhomogeneous materials like cast irons. On the basis of fatigue data determined in only nine fatigue tests, the enhanced method “PHYBALSB” allows the calculation of Woehler (S-N) curves for different probabilities of failure (Scatter-Bands). This shorttime procedure results in a reduction in experimental time up to 90% and leads to enormous scientific and economic advantages.

The effects of PAM on the gravity-induced flocculation of colloidal particles in binary suspensions

The effects of polyacrylamides (PAM) at different ionic strengths on the gravity-induced heteroflocculation behavior of binary suspensions are investigated based on the turbidity measurement method in the present paper. For the binary suspensions composed of two different-sized latexes, it is found that the stability ratios of the suspensions decrease with the increase of either the PAM or the electrolyte concentration, and with the increase of the size differences between two latex components of the binary suspension. From the pictures of scanning electron microscopy, it is also interesting to find that, even when both latexes are negatively charged, the small latexes can still be adsorbed at the interparticle regions between two large latexes through the bridge formed by PAM between the small and the large latexes.

The effects of multivalent electrolytes on the gravity-induced flocculation of colloidal particles in binary suspensions

The effects of multivalent electrolytes on gravity-induced heteroflocculation behavior of binary suspensions under different gravity forces are investigated based on the turbidity measurement method. The heteroflocculation behavior of the binary suspensions described by the stability ratio is well analyzed by using the stability diagram and the DLVO theory. It is found that the stability ratios of the binary suspensions decrease with the increase of either the electrolyte concentration and valence or the gravity forces and with the decrease of the size ratio of the latexes components of the binary suspension. Because the theoretical stability ratios obtained by the trajectory analysis method are always higher than the corresponding heteroflocculation experimental values obtained by turbidity measurements, we successfully apply the “regressed” surface potentials determined from the flocculation experiments of monodispersed suspension to predict the stability ratios of the corresponded binary suspension.

Sand and mud flux estimates using acoustic and optical backscatter sensors: measurements seaward of the Wash, southern North Sea

Abstract Optical and acoustic backscatter sensors, more sensitive to fine and sandy sediment respectively, were used to measure the mud and sand components of a mixed suspension at a site seaward of the Wash embayment, in the southern North Sea. Data were acquired from a free-standing instrument frame during a five-week deployment in 12 m water depth about 6 km offshore. Suspended mud at this site was characterized by tidal advection of fine sediment along the coast resulting in semi-diurnal peaks in concentration near slack water. Suspended sand concentrations correlated well with tidal current speeds indicating local resuspension behaviour. Predicted sand flux direction followed the residual current while mud fluxes at the site were different in direction to both the residual current and sand flux. Residual fluxes may be biased by cumulative errors resulting from instrument calibration and inferred vertical concentration profiles. These factors are assessed in relation to both predicted flux magnitudes and directions.

Different electrospray tandem mass spectrometric approaches for rapid characterization of phospholipid classes of Curosurf, a natural pulmonary surfactant.

Curosurf is a pulmonary surfactant used in the treatment or prophylaxis of neonatal respiratory distress syndrome. It contains low molecular weight hydrophobic apoproteins and a series of lipids including phosphatidylcholines, lisophosphatidylcholines, phosphatidylethanolamines, sphingomyelins, phosphatidylinositols, phosphatidylglycerols and phosphatidylserines. In the present work, a rapid method to qualitatively map the Curosurf phospholipid classes without prior derivatization or chromatographic separations is described. In particular, a series of specific electrospray tandem mass spectrometric (ES-MS/MS) experiments, i.e. product ion, precursor ion and neutral loss scans, were chosen on the basis of the chemical nature of each phospholipid class and then used to identify single components of the commercial suspension, directly infused into the ion source of the mass spectrometer.

Evaluation of the in Situ Polymerization Kinetics for the Gelcasting of Ceramic Foams

Recent processing technologies have employed the in situ polymerization of organic monomers to consolidate particulate suspensions of ceramics into dense and strong bodies. The same principle has been applied to solidify foamed ceramic suspensions with great success. In this work, the parameters that influence the polymerization kinetics of acrylic monomers were investigated in systems containing the separate components of a ceramic suspension, with and without the generation of foam. The main objective was to obtain control of the onset time for polymerization (I d ), which is a critical factor in the processing of foamed ceramics. Analysis of the exothermic profiles registered during polymerization revealed that the polymerization onset is markedly influenced by a number of variables, including the solids concentration, initial temperature, pH, and oxygen concentration.

医薬品アレルギーとヒスタミン 医薬品添加物カルボキシメチルセルロースナトリウムによるアレルギー反応に関する研究

Histamine plays an important role in both inflammation and gastric acid secretion, while it also acts as a neurotransmitter in the mammalian brain. In particular, histamine plays a central role in the immediate hypersensitivity and allergic response as a mediator released from mast cells and basophils.The use of in vitro histamine release experiments to identify antigens in drug allergies is thus considered to be useful. A highly sensitive assay for histamine is required for in vitro release experiments.We experienced a patient who developed an anaphylactic reaction to a barium sulfate suspension after under-going an upper gastrointestinal examination, and identified carboxymethylcellulose sodium (CMC-Na) to be an antigen in the barium sulfate suspension, using the skin-scratch test and in vitro histamine release.A 63-year-old woman was admitted to the hospital because of an anaphylactic reaction after undergoing a double-contrast upper gastrointestinal examination. After obtaining the patient informed consent, we conducted skin-scratch tests for each of the components in the barium sulfate suspension to identify any antigens. A positive reaction was observed for CMC-Na. No such reaction was observed for any other components of the barium sulfate suspension and gas producing granules. The three normal subjects had no response to all agents tested. In addition, the degree of histamine release from the isolated leukocytes induced by CMC-Na was studied in vitro. The leukocytes were isolated by the centrifugation of the peripheral blood on the Ficoll-iothalamate meglumine solution. The histamine content was determined by lon-Pair HPLC.The leukocytes from the patient responded to CMC-Na at a concentration range from 10-4.5% to 10-2.6%, while those from normal subjects did not. The dose-response curve for the effect of CMC-Na on the histamine release from leukocytes from the patient was bell-shaped. The results of the present study as a whole indicated CMC-Na to be the antigen responsible for the anaphylactic response to the barium suspension in our patient. Although not a common complication, such a reaction may occur in patients sensitized to CMC-Na.CMC-Na is widely used as a suspending agent in pharmaceuticals, certain food products and cosmetics. Although CMC-Na has been thought to be inert and not absorbed, our findings suggest that the patient was sensitized to CMC-Na through such routes.

Using mechanical-acoustical reciprocity for diagnosis of structure borne sound in vehicles

The low frequency interior noise in cars is for a large part the result of structure borne excitation. The transfer of the structure borne sound involves a large number of components of the engine suspension, wheel suspension and chassis which are all potentially contributing to the overall noise level. This process can be analyzed through acombination of transfer function measurements with operational measurements under normal vehicle conditions. This technique, called transfer path analysis, requires large numbers of transfer function measurements with excitation of the body or cabin at the rubber mountings. Unfortunately, bad access to these crucial measurement locations causes either high instrumentation and measurement effort or less accurate measurement data. The practicality and quality of the measurements can be improved by using reciprocal measurements for the mechano-acoustic transfer of the body or cabin structure; a loudspeaker in the cavity is used for the reciprocal excitation. The reciprocity technique also allows better insight in the acoustic response of the cavity