Combination Of Suspension Research Articles

Preparation of microbeads grafted with poly(2-(acryloyloxy)ethyl]trimethylammonium chloride) cationic polyelectrolyte as recyclable and effective adsorbents for organic dyes

Brush polymers have been widely used as a suitable replacement for many adsorbents due to their economical cost, reusability, and mechanical strength. Here, cationic polyelectrolyte microbeads poly(2-hydroxyethyl methacrylate/ethylene dimethacrylate)-g-poly(2-(acryloyloxy)ethyl]trimethylammonium chloride) marked as p(HEMA/EDMA)-g-p(AEtMAC) were prepared by a combination of suspension and controlled radical polymerization methods. Microbeads displayed nonporous, spherical, and uniform morphology with a size of about 250 μm. Thermal stability decreased after grafting of p(AEtMAC) onto the surface of p(HEMA/EDMA)-Br and the final microbeads p(HEMA/EDMA)-g-p(AEtMAC) exhibited the onset degradation temperature of 200 °C. The adsorption of Coomassie Brilliant Blue G250 (CBB) and methyl orange (MO) anionic dyes at different adsorbent dosages (0.5–3 g L−1) and constant concentration of dye (50 mg L−1) was investigated. The adsorbent at the optimum dosage of 2 g L−1 was selected. More than 90% of the mentioned dyes were removed in the optimum pH range of 5–6. The maximum adsorption capacities 145 and 135 mg dye g−1 adsorbent were obtained for MO and CBB dyes, respectively, at ambient temperature and 300 mg L−1 dye concentration. Adsorptions of the MO and CBB on the adsorbent were well fitted to Temkin and Langmuir isotherm models, respectively, which obeyed the quasi-second-order kinetic model. Adsorption enthalpy change values for MO and CBB were found to be 32.17 and 17.59 KJ mol−1, correspondingly, which indicated the exothermic property and the physical nature of the adsorption. Furthermore, the entropy change values of 130 and 70 J mol−1 were determined for MO and CBB, respectively. Positive values of entropy changes are related to the increase in irregularity during dye adsorption on the cationic adsorbent.

Bridges with multiple structural systems: The example of Trilj Bridge reconstruction in Croatia

Development of multiple structural systems for bridges is useful in the design of new bridges and rehabilitation of existing bridges. This paper briefly presents some existing bridges with multiple structural systems and succinctly discusses design ideas for bridges with such systems. As an example of a bridge with multiple structural systems, the paper presents the reconstruction of a pedestrian suspension bridge in the City of Trilj, Croatia. The new bridge’s load-bearing structure is composed of several structural systems. Namely, the reconstructed bridge is a combination of suspension, cable-stayed and stress-ribbon bridge, which is laterally restrained with horizontal tensioned ropes. Numerical analysis was conducted on the renovated bridge. The results have shown an acceptable levels of stresses and deflections verifying the structural safety of the restored bridge. It is believed that this example of the bridge renovation may be useful in the design of new and strengthening of existing similar bridges.

Effect of bolster suspension parameters of three-piece freight bogie on the lateral frame force

ABSTRACTMonitoring of lateral frame forces caused by the Rail vehicles is becoming increasingly important as both speeds and loads are increasing along with putting in more continuous welded rail in use. In this study on a freight wagon fitted with three-piece bogies, the effect of bogie lateral stiffness, snubbing force and wedge coefficient of friction on the lateral frame force is presented. A multibody model in NUCARS consisting of 11 rigid bodies and 49 dof's has been made for performing simulation analysis on 30 different bolster suspension combinations. The simulation results suggest that increasing the snubbing force and/or the wedge coefficient of friction increase the lateral frame forces in general. Increasing the lateral stiffness of the bogie along with the snubbing force cause increase in the lateral frame force. The lateral frame force depends upon the relative interplay of the lateral bogie stiffness and the snubbing force for the subject suspension designs.

Estimation of body input force transmission change due to parts’ modification using the impedance method under rolling excitation

This study aims to estimate the change in suspension to body input force transmission due to the softening of the connecting elastomer under rolling excitation. In this respect, the suspension coupled to a vehicle body via an elastomer bushing is modeled using point impedance. A numerical study is performed for achievable force reduction due to a softened bush under the influence of different impedance combinations for the suspension and the vehicle body. Following a numerical study, the proposed model is validated through empirical testing of McPherson strut type suspension in the lateral arm Y direction and multilink type rear suspension in the front mount X direction, which represent extremely stiff and extremely soft coupling cases for the suspension type, respectively. Due to the difficulties in measuring road-induced operational forces within an actual vehicle, a validation test is performed using a previously developed rig that enables direct measurement of the force without modifying the structure of the suspension. Additionally, the rig-measured force, which is potentially misleading due to the large deviation in stiffness between the rig and an actual vehicle, is investigated under varying combinations of suspension and bush stiffness.

High velocity suspension flame spraying (HVSFS) of metal doped bioceramic coatings

•Bioceramic coatings doped with metals for antibacterial effect.•Combination of suspension and precursor flame spraying.•Successful deposition of submicron metallic particles in bioceramic matrix.

Fabrication of magnetic field induced structural colored films with tunable colors and its application on security materials

A flexible, magnetic field induced structurally colored films with brilliant colors and high physical rigidity were reported in this article. Using an external magnetic field, the photocurable colloidal suspensions that containing superparamagnetic Fe3O4@C colloidal nanocrystal clusters (CNCs) could polymerize under UV light. After polymerization, the films with different colors (red, green, blue) were obtained. Through combination of suspensions which contains Fe3O4@C CNCs with different sizes, a series of multi-colored films were obtained. Moreover, these structural colors can be patterned easily by photolithography and various structural colored patterns were shown in the article. The structural colored patterns could conceal or display its color according to the changing of background which makes them hold significant potential applications for security materials.

Microfluidic-based multiplex immunoassay system integrated with an array of QD-encoded microbeads

Here, we developed a multiplex immunoassay platform within microfluidic devices that combines suspension and the planar microarray format. For the suspension microarray format, QD-embedded polymeric microbeads with an average diameter of 24μm were prepared using the Shirasu Porous Glass (SPG) membrane emulsification technique. To furnish the microbeads with resolvable spectral codes, QDs with two different colors (450nm for blue and 520nm for green) were used and different spectral codes were obtained by changing the ratio of emission intensity of the two different QDs within the microbeads. The surfaces of the QD-encoded microbeads were then functionalized with probe antibodies for immunoassays. The planar microarray format was achieved by an array of microholes fabricated in PDMS. Each microhole was designed to trap a single microbead and eventually generated a microbeads array within the microfluidic system. The feasibility of the microbead array within microfluidic devices for use in a multiplex immunoassay was demonstrated by immunobinding assays between IgG and anti-IgG and/or between IgM and anti-IgM. Furthermore, the resultant microbead-based on-chip assay could be used for a sandwich assay to detect prostate-specific antigen (PSA), a model cancer marker, with a detection limit of 1ng/mL. The combination of suspension and the planar microarray format enabled the spatial location of individual microbeads within physically separated regions and thus facilitated the simultaneous determination of different targets that interacted with the corresponding microbeads.

Study on Microfine Cement Grouting Material for Silty Fine Sand Stratum

Silty fine sand is the second smallest sand with a particle diameter ranging from 0.0625 to 0.120 mm.This kind of sand exists in a large amount in Beijing subway excavation project. Due to the poor self-stabilization of this stratum,seeping , sand flow and collapse take place frequently. Grouting materials such as Portland cement and soluble glass (also called sodium silicate) are employed in most of excavation projects to reinforce this sand stratum. However, the reinforcement is not effective, leading to a large amount of accidents in the process of construction. The reason may be attributed to the fact that Portland cement is unable to penetrate into the stratum and the strength of soluble glass (0.6MPa) is too weak to resist the stratum pressure. To solve this problem, a modified microfine cement grouting material able to penetrate into silty fine sand stratum is developed in this paper. A combination of suspension and diluent is used to increase the penetration extension of the grouts,and the experimental results reveal that the addition of the mixture of suspension and diluent in microfine cement grouting materials improves the penetration property substantially.

Fabrication of Direct Oxidation Solid Oxide Fuel Cell Anodes Using a Novel Atmospheric Plasma Spraying Technique

Composite coatings of CuO and samaria-doped ceria (SDC) have been fabricated by atmospheric plasma spraying using a combination of suspension and dry-powder plasma spray techniques. The coatings prepared using this novel hybrid technique demonstrate a finer microstructure than similar coatings prepared using conventional dry-powder methods. The coatings consist of fully-melted and partially-melted phases of both CuO and SDC. During deposition, a large portion of the CuO was reduced to Cu2O. The influence of processing conditions on deposition efficiency and porosity were investigated, with a plasma power of 77 kW leading to a maximum in coating porosity. Improvement of the dispersion of the CuO suspension by adjusting the pH led to a finer network of CuO particles in the fabricated coating.

Tsunamis as geomorphic crises: Lessons from the December 26, 2004 tsunami in Lhok Nga, West Banda Aceh (Sumatra, Indonesia)

Large tsunamis are major geomorphic crises, since they imply extensive erosion, sediment transport and deposition in a few minutes and over hundreds of kilometres of coast. Nevertheless, little is known about their geomorphologic imprints. The December 26, 2004 tsunami in Sumatra (Indonesia) was one of the largest and deadliest tsunamis in recorded human history. We present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the Lhok Nga Bay, located to the West of Banda Aceh (northwest Sumatra). The geomorphological impact of the tsunami is evidenced by: beach erosion (some beaches have almost disappeared); destruction of sand barriers protecting the lagoons or at river mouths; numerous erosion escarpments typically in the order of 0.5–1.5 m when capped by soil and more than 2 m in dunes; bank erosion in the river beds (the retreat along the main river is in the order of 5–15 m, with local retreats exceeding 30 m); large scars typically 20–50 cm deep on slopes; dislodgement of blocks along fractures and structural ramps on cliffs. The upper limit of erosion appears as a continuous trimline at 20–30 m a.s.l., locally reaching 50 m. The erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds. The overall coastal retreat from Lampuuk to Leupung was 60 m (550,000 m 2) and locally exceeded 150 m. Over 276,000 m 3 of coastal sediments were eroded by the tsunami along the 9.2 km of sandy coast. The mean erosion rate of the beaches was ~ 30 m 3/m of coast and locally exceeded 80 m 3/m. The most eroded coasts were tangent to the tsunami wave train, which was coming from the southwest. The fringing reefs were not efficient in reducing the erosional impact of the tsunami. The 220 boulders measured range from 0.3 to 7.2 m large (typically 0.7–1.5 m), with weights from over 50 kg up to 85 t. We found one boulder, less than 1 m large, at 1 km from the coastline, but all the others were transported less than 450 m (< 7 m a.s.l.). No fining landward boulder size distribution could be detected. The coincidence of different size modes, from boulders to fine sands, with independent spatial distributions, suggests that all the material was not transported in suspension, but rather by a combination of suspension and bed load transport. Finally, the spatial and size distributions of tsunami boulder deposits mostly depend on the location and characteristics of their source (coral reef, beach rock, platform, dams), together with clast and surface interference during transport. One year after, the coastal environment in northwest Sumatra is still in a post-tsunami dynamic. Thus, the difference between the largest tsunamis (height > 30 m) and the moderate tsunamis (height < 10 m) could be their long-term impact on coastal environments.

Retroviral vector production using suspension-adapted 293GPG cells in a 3L acoustic filter-based perfusion bioreactor

Recombinant retroviruses are now an established tool for gene delivery. Presently they are mainly produced using adherent cells. However, due to the restrictive nature of adherent cell culture, this mode of production is hampered by low cell-specific productivity and small production units. The large-scale production of retroviral vectors could benefit from the adaptation of retrovirus packaging cell lines to suspension culture. Here, we describe the ability of a 293 packaging cell line to produce retroviral vectors in suspension culture at high titer. Adherent 293GPG cells, producing a Moloney Murine Leukemia Virus (MoMLV) retrovirus vector pseudotyped with the vesicular stomatitis virus G (VSVG) envelope protein and expressing a TK-GFP fusion protein, were adapted to suspension culture in calcium-free DMEM. At a cell density similar to adherent cell culture, the suspension culture produced retroviral vector consistently in the range of 1 x 10(7) infectious viral particles/mL (IVP/mL), with a specific productivity threefold higher than adherent culture. Furthermore, at the same medium replacement frequency, the suspension producer cells could be cultured at higher density than their adherent counterparts, which resulted in virus titer of 3-4 x 10(7) IVP/mL at 11.0 x 10(6) cells/mL. This corresponds to a 10-fold increase in viral concentration compared to adherent cells. The capacity to up scale the retroviral vector production was also demonstrated by performing a 2 VVD perfusion culture for 9 days in a 3L Chemap bioreactor. The combination of suspension and perfusion led to a 20-fold increase in maximum virus productivity compared to the adherent culture.

The physical mechanism for the production of hydrophilic polymer microparticles from aqueous suspensions

AbstractA previously reported method of producing spherical, hydrophilic microparticles by aqueous suspension polymerization is experimentally investigated. The phase separation is the result of a salting‐out phenomenon. Characteristics of the salting‐out effect between the monomer and suspending phase of aqueous NaCl solution are studied. The size and shape of the produced particles are characterized. It is concluded that the mechanism of polymerization is actually a combination of suspension and solution polymerization, and that the water content in the monomer phase is low enough to produce structurally homogeneous particles.

Reading segmented grain-size curves

SummaryCumulative curves of grain-size against frequency often show segmented shapes which have been interpreted as the result of combination of normally distributed populations. The origin of the segments is explored by the examination of two classes of models, truncation and mixing. Similar curves may be generated by a variety of models. The segments rarely reflect precisely the original populations. Simulation of the tri-segmented curves commonly ascribed to combinations of suspension, saltation and traction populations shows that the characteristics of the contributing populations are not consistent with these three modes of transportation.

Furnace Heat Absorption in a Spreader-Stoker-Fired Steam Generator: 1—Furnace Heat-Absorption Efficiency as Shown by Enthalpy of Gases Leaving the Furnace

Abstract This paper is part of the fifth of a series of reports on investigations of heat absorption and distribution of heat transfer in large steam-boiler furnaces, sponsored by the ASME Special Research Committee on Furnace Performance Factors. The furnace heat absorption was determined from the temperature and composition of the furnace exit gases in fifteen tests on a steam generator rated at 165,000 lb per hr of steam at 915 psig and 740 F at the superheater outlet, and which is fired by a spreader stoker on a front-discharge traveling grate. The effect on furnace heat-absorption efficiency is shown for variation of (a) the heat available in the furnace, (b) the excess air, (c) the percentage of combustion air admitted over the fuel bed, and (d) the condition of the furnace walls with respect to ash deposits. Detailed data on the distribution of gas temperature and of excess air in the furnace are presented. The experimental values for the furnace heat-absorption efficiency did not compare favorably with values calculated by either the Stefan-Boltzmann or the Wohlenberg equations. There is evidence, however, that the performance of a spreader-stoker-fired furnace might be predicted by the Wohlenberg equation if it were modified to allow for heat transfer resulting from a combination of suspension and fixed-bed burning.