Circular Chamber Research Articles

Cocurrent and countercurrent extraction based on a novel three-dimensional vortex microextractor

A single-stage cocurrent arrangement was described based on a three-dimensional (3-D) vortex microextractor using the vortex effect, and the 3-D microextractor was further modified to establish a countercurrent arrangement without any interstage pumps or check valves. The 3-D vortex microextractor mainly composed of an inlet channel, two circular chambers, a slender cylindrical connection channel, and an outlet channel. In both cocurrent and countercurrent operations, the flow pattern and extraction performance were investigated and analyzed. In the cocurrent arrangement, the hydraulics experiment results demonstrated that the 3-D vortex microextractor could passively and effectively produce droplets even at high fluxes of the dispersed phase. The extraction experiment results confirmed that the vortex effect of the 3-D microextractor could enhance the shear force and facilitate the production of droplets, consequently enhancing the extraction efficiency. Furthermore, it was experimentally proved that the countercurrent arrangement could be realized relying on the modified 3-D microextractor and alternatively pulsed feeding of both phases.

Suraqalatia brasieri n.gen., n.sp. (larger foraminifera) from the Maastrichtian of Sulaimani area in northern Iraq

Suraqalatia brasieri n.gen., n.sp. from the family Dicyclinidae Loeblich and Tappan 1964 occurs on the Maastrichtian carbonate platform of northern Iraq. The new genus is recognizable by its large very compressed conical test, up to 55–70 mm in diameter, to 0.3–1.6 mm in thickness, planspiral cooling having very small proloculus in the initial part and later circular chambers including numerous chamberlets with an agglutinated wall. Suraqalatia brasieri n.gen., n.sp. is associated with textulariids, miliolids and rotaliids as Loftusia elongata Cox, L. morgani Douville, Orbitoides medius d’Archiac, O. megaloformis Papp & Kupper, O. gruenbachensis Papp, O. apiculatus Schlumberger, Omphalocyclus macroporus (Lamarck), Siderolites calcitrapoides Lamarck, Sirtina orbitoidiformis Bronnimann & Wirz. The associated macrofauna comprises large and rich giant rudists (Preradiolites sp.), other bivalves (Gryphaea sp. and Glycymeris sp.), gastropods (Acteonella sp.), echinoderms and corals. The fauna indicates shallow marine carbonate platform conditions within the Maastrichtian green house. It is also worth mentioning that the new genus has only been recorded from the Maastrichtian age.

A multi-staining chip using hydrophobic valves for exfoliative cytology in cancer

Exfoliative cytology is a highly established technique for the diagnosis of tumors. Various microfluidic devices have been developed to minimize the sample numbers by conjugating multiple antibodies in a single sample. However, the previous multi-staining devices require complex control lines and valves operated by external power sources, to deliver multiple antibodies separately for a single sample. In addition, most of these devices are composed of hydrophobic materials, causing unreliable results due to the non-specific binding of antibodies. Here, we present a multi-staining chip using hydrophobic valves, which is formed by the partial treatment of 2-hydroxyethyl methacrylate (HEMA). Our chip consists of a circular chamber, divided into six equal fan-shaped regions. Switchable injection ports are located at the center of the chamber and at the middle of the arc of each fan-shaped zone. Thus, our device is beneficial for minimizing the control lines, since pre-treatment solutions flow from the center to outer ports, while six different antibodies are introduced oppositely from the outer ports. Furthermore, hydrophobic narrow channels, connecting the central region and each of the six fan-shaped zones, are closed by capillary effect, thus preventing the fluidic mixing without external power sources. Meanwhile, HEMA treatment on the exterior region results in hydrophobic-to-hydrophilic transition and prevents the non-specific binding of antibodies. For the application, we measured the expression of six different antibodies in a single sample using our device. The expression levels of each antibody highly matched the conventional immunocytochemistry results. Our device enables cancer screening with a small number of antibodies for a single sample.

DETONATION ROCKET ENGINES PROCESSES INVESTIGATION

The article focuses on the problems of the detonation engines specific characteristics increasing. The schemes that are known have several disadvantages, so despite the seventy years history they are still at the experimentation stage.To improve the performance of detonation engines the solutions are suggested. The new scheme provides the initiation of the engine in pulse detonation tubes using rotating detonation wave. It is distributed in channel located between the spray head and a circular tubular combustion chamber. The advantage of the new scheme is the fact that batch filling of the combustion chamber is not needed anymore, initiation of detonation of each cycle and a high part of fuel detonates in the axial direction.Experimental studies were conducted in order to test the operability of the scheme. For this purpose, two models and test-banch were developed.Also, one of the tasks of the experiments was to test the possibility of passing deflagration and detonation fronts through the mesh barriers. For this pyrpose, the mesh is installed between the main channel and offshoot. Moments of launches including the velocity of fronts are illustrated in the figures.The results showed that the detonation and deflagration are distributed through offshoot, but their speed drops more than 2 times. This result is expected, and described in publications. The mesh cell size that blocks deflagration and detonation fronts in a mixture of propane air is determined. Thus, the workability of the proposed scheme of detonation rocket engine with initiation impulses rotating detonation wave was confirmed experimentally.

Heart-on-a-Chip: An Investigation of the Influence of Static and Perfusion Conditions on Cardiac (H9C2) Cell Proliferation, Morphology, and Alignment.

Lab-on-a-chip systems are increasingly used as tools for cultures and investigation of cardiac cells. In this article, we present how the geometry of microsystems and microenvironmental conditions (static and perfusion) influence the proliferation, morphology, and alignment of cardiac cells (rat cardiomyoblasts-H9C2). Additionally, studies of cell growth after incubation with verapamil hydrochloride were performed. For this purpose, poly(dimethylsiloxane) (PDMS)/glass microfluidic systems with three different geometries of microchambers (a circular chamber, a longitudinal channel, and three parallel microchannels separated by two rows of micropillars) were prepared. It was found that static conditions did not enhance the growth of H9C2 cells in the microsystems. On the contrary, perfusion conditions had an influence on division, morphology, and the arrangement of the cells. The highest number of cells, their parallel orientation, and their elongated morphology were obtained in the longitudinal microchannel. It showed that this kind of microsystem can be used to understand processes in heart tissue in detail and to test newly developed compounds applied in the treatment of cardiac diseases.

Migratory orientation in a narrow avian hybrid zone.

BackgroundZones of contact between closely related taxa with divergent migratory routes, termed migratory divides, have been suggested as areas where hybrid offspring may have intermediate and inferior migratory routes, resulting in low fitness of hybrids and thereby promoting speciation. In the Rocky Mountains of Canada there is a narrow hybrid zone between Audubon’s and myrtle warblers that is likely maintained by selection against hybrids. Band recoveries and isotopic studies indicate that this hybrid zone broadly corresponds to the location of a possible migratory divide, with Audubon’s warblers migrating south-southwest and myrtle warblers migrating southeast. We tested a key prediction of the migratory divide hypothesis: that genetic background would be predictive of migratory orientation among warblers in the center of the hybrid zone.MethodsWe recorded fall migratory orientation of wild-caught migrating warblers in the center of the hybrid zone as measured by video-based monitoring of migratory restlessness in circular orientation chambers. We then tested whether there was a relationship between migratory orientation and genetic background, as measured using a set of species-specific diagnostic genetic markers.ResultsWe did not detect a significant association between orientation and genetic background. There was large variation among individuals in orientation direction. Mean orientation was towards the NE, surprising for birds on fall migration, but aligned with the mountain valley in which the study took place.ConclusionsOnly one other study has directly analyzed migratory orientation among naturally-produced hybrids in a migratory divide. While the other study showed an association between genetic background and orientation, we did not observe such an association in yellow-rumped warblers. We discuss possible reasons, including the possibility of a lack of a strong migratory divide in this hybrid zone and/or methodological limitations that may have prevented accurate measurements of long-distance migratory orientation.

Rotational magneto-acousto-electric tomography (MAET): theory and experimental validation

We present a novel two-dimensional (2D) MAET scanner, with a rotating object of interest and two fixed pairs of electrodes. Such an acquisition scheme, with our novel reconstruction techniques, recovers the boundaries of the regions of constant conductivity uniformly well, regardless of their orientation. We also present a general image reconstruction algorithm for the 2D MAET in a circular chamber with point-like electrodes immersed into the saline surrounding the object. An alternative linearized reconstruction procedure is developed, suitable for recovering the material interfaces (boundaries) when a non-ideal piezoelectric transducer is used for acoustic excitation. The work of the scanner and the linearized reconstruction algorithm is demonstrated using several phantoms made of high-contrast materials and a biological sample.

Habitat selection of juvenile sole (Solea solea L.): Consequences for shoreface nourishment

The shallow coastal zone is an essential nursery habitat for juvenile flatfish species such as sole (Solea solea L.). The increased frequency of shoreface nourishments along the coast is likely to affect this nursery function by altering important habitat conditions, including sediment grain size. Sediment preference of juvenile sole (41–91mm) was studied in a circular preference chamber in order to understand the relationship between grain size and sole distribution. The preference tests were carried out at 11°C and 20°C to reflect seasonal influences. The juveniles showed a significant preference for finer sediments. This preference was not length dependent (within the length range tested) nor affected by either temperatures. Juvenile sole have a small home range and are not expected to move in response to unfavourable conditions. As a result, habitat alterations may have consequences for juvenile survival and subsequently for recruitment to adult populations. It is therefore important to carefully consider nourishment grain size characteristics to safeguard suitable nursery habitats for juvenile sole.

On-chip Virtual Vortex Gear

We observed an interesting phenomenon of coupled vortices in a microfluidic channel with different driving pressure. We call this phenomenon “Virtual Vortex Gear”, as the vortices transmitting like a set of gear. The channel has an elbow and a circular chamber outside the bend point. In addition to the phenomenon, we can also control the flow into the chamber by adjusting the driving pressure and we name this feature “Virtual Valve”. Microbeads were used as tracers in the experiments. The relation between the vortices and driving pressure is discussed. With simulation on COMSOL, we evaluate Virtual Valve and determine the proper size and shape for the design.

Estimation of biocovers surface fluxes by two tools under Canadian atmospheric real conditions

In order to investigate the reduction of greenhouse gases by novel and ecological bio-process, three passive methane oxidation biocovers (PMOB) were installed in St-Nicephore landfill in Quebec, Canada. The aim of the present paper is to estimate surface fluxes of volatile organic compounds (VOC) using two different direct measurement methods. Rectangular and circular flux chambers were used to collect the emitted biogas at the surface of PMOB. The sampling period took place from June to September 2012. An analytical method was developed to analyse the landfill biogas. Gas chromatography-mass spectrometry (GC/MS) and solid-phase micro-extraction (SPME) fibre were used to identify and quantify VOC. A number of VOC compounds were identified and quantified in landfill biogas. During the present study, more attention was given to benzene, toluene, ethyl-benzene, and xylene (known in the literature as BTEX) surface fluxes. The surface emission fluxes varied from 182.5 μg/m2/year to 3.8 mg/m2/year.

Magnetofluidics for manipulation of convective heat transfer

We report heat transfer manipulation and control in a magnetofluidic device. The device consists of a circular chamber with a heat source on top and is positioned next to a permanent magnet that creates a non-uniform magnetic field. Convective heat transfer was evaluated and compared for three cases: DI-water, ferrofluid, and ferrofluid under the magnetic field. Experimental results indicate enhancement of convective heat transfer with the use of diluted ferrofluid as the working fluid. However, we observed a reduction in outlet temperature and Nusselt number in the presence of a non-uniform magnetic field. In addition, we report a full simulation of transport phenomena in the system explaining the physics of this phenomenon. The simulation results agree with the experimental data, and show the same trends.

Electrical impedance tomography methods for miniaturised 3D systems

Abstract In this study, we explore the potential of electrical impedance tomography (EIT) for miniaturised 3D samples to provide a non-invasive approach for future applications in tissue engineering and 3D cell culturing. We evaluated two different electrode configurations using an array of nine circular chambers (Ø 10 mm), each having eight gold plated needle electrodes vertically integrated along the chamber perimeter. As first method, the adjacent electrode configuration was tested solving the computationally simple back-projection algorithm using Comsol Multiphysics in time-difference EIT (t-EIT). Subsequently, a more elaborate method based on the “polar-offset” configuration (having an additional electrode at the centre of the chamber) was evaluated using linear t-EIT and linear weighted frequency-difference EIT (f-EIT). Image reconstruction was done using a customised algorithm that has been previously validated for EIT imaging of neural activity. All the finite element simulations and impedance measurements on test objects leading to image reconstruction utilised an electrolyte having an ionic strength close to physiological solutions. The chosen number of electrodes and consequently number of electrode configurations aimed at maximising the quality of image reconstruction while minimising the number of required measurements. This is significant when designing a technique suitable for tissue engineering applications where time-based monitoring of cellular behaviour in 3D scaffolds is of interest. The performed tests indicated that the method based on the adjacent configuration in combination with the back-projection algorithm was only able to provide image reconstruction when using a test object having a higher conductivity than the background electrolyte. Due to limitations in the mesh quality, the reconstructed image had significant irregularities and the position was slightly shifted toward the perimeter of the chamber. On the other hand, the method based on the polar-offset configuration combined with the customised algorithm proved to be suitable for image reconstruction when using non-conductive and cell-based test objects (down to 1% of the measurement chamber volume), indicating its suitability for future tissue engineering applications with polymeric scaffolds.

A parabolic solvent chamber model for simulating the solvent vapor extraction (VAPEX) heavy oil recovery process

During the solvent vapor extraction (VAPEX) process, a heavy oil reservoir can be divided into three different zones in terms of its fluid saturations, namely, the solvent chamber, transition zone, and untouched heavy oil zone. In the past, the solvent chamber was assumed to be a linear or circular shape in the previous studies. However, it has been observed to be close to a parabolic shape in many laboratory VAPEX tests. In this paper, a new parabolic solvent chamber model in the concave or convex case is formulated to predict the solvent chamber evolution and the heavy oil production in the VAPEX heavy oil recovery process. In the experiment, each recorded digital solvent chamber image at a different time is digitized to determine the solvent chamber shape by analyzing the sudden change of the gray level of each pixel. In theory, the overall discrepancy between the predicted and digitized solvent chambers is minimized by adjusting the transition-zone thickness. It is found that in comparison with the linear and circular solvent chamber models, the parabolic solvent chamber model gives the best prediction of the solvent chamber evolution, especially in the spreading phase. In addition, the maximum transition-zone thickness variation of 13.1% during the entire VAPEX test indicates that the transition-zone thickness can be assumed to be constant. Similar to the other solvent chamber models, the parabolic solvent chamber model can adequately predict the cumulative heavy oil production. The relatively large error of the predicted cumulative heavy oil production is caused by a commonly used assumption. The initial oil saturation in the transition zone is assumed to reduce to the residual oil saturation once the transition zone becomes an incremental part of the solvent chamber. This major theoretical assumption needs to be further investigated.

Acoustic End-Correction in a Flow-Reversal End Chamber Muffler: A Semi-Analytical Approach

This work presents a semi-analytical technique based on the Green’s function and uniform-piston driven model to determine the end-correction length [Formula: see text] in an axially long flow-reversal end chamber muffler having an end-inlet and an end-outlet. The semi-analytical procedure is based on the 3D analytical uniform piston-driven model for obtaining the impedance [Z] matrix parameters and numerically evaluating the frequency [Formula: see text] at which the imaginary part of the cross-impedance parameter [Formula: see text] crosses the frequency axis at the first instance. The frequency [Formula: see text] corresponds to the low-frequency peak in the transmission loss (TL) spectrum of the axially long flow-reversal end-chamber muffler obtained a priori to its computation by considering the influence of higher order evanescent transverse modes. The effective chamber length (and thence, the end-correction length) in the low-frequency range are determined by using the expression for resonance frequency of a classical quarter-wave resonator. This method is employed to determine the end-correction in axially long elliptical cylindrical end chambers and circular cylindrical end chambers (with or without a rigid concentric circular pass-tube). The TL graph predicted by the 1D axial plane wave model (incorporating the end-correction length) is shown to be in an excellent agreement with that obtained by the 3D analytical approach and an experimental result (from literature) up to the low-frequency limit, thereby validating the semi-analytical technique. Parametric studies are conducted using the proposed semi-analytical method to investigate and qualitatively explain the effect of angular location and offset distance of the end ports and the pass-tube diameter on the end-correction length, thereby yielding important insights into the influence of transverse evanescent modes on dominant axial plane wave modes of the axially long end-chamber. Development of an empirical end-correction expression in a flow-reversal circular end-chamber with offset inlet and outlet ports is a practically useful contribution of this work.

Uniform electric field generation in circular multi-well culture plates using polymeric inserts.

Applying uniform electric field (EF) in vitro in the physiological range has been achieved in rectangular shaped microchannels. However, in a circular-shaped device, it is difficult to create uniform EF from two electric potentials due to different electrical resistances originated from the length difference between the diameter of the circle and the length of any parallel chord of the bottom circular chamber where cells are cultured. To address this challenge, we develop a three-dimensional (3D) computer-aided designed (CAD) polymeric insert to create uniform EF in circular shaped multi-well culture plates. A uniform EF with a coefficient of variation (CV) of 1.2% in the 6-well plate can be generated with an effective stimulation area percentage of 69.5%. In particular, NIH/3T3 mouse embryonic fibroblast cells are used to validate the performance of the 3D designed Poly(methyl methacrylate) (PMMA) inserts in a circular-shaped 6-well plate. The CAD based inserts can be easily scaled up (i.e., 100 mm dishes) to further increase effective stimulation area percentages, and also be implemented in commercially available cultureware for a wide variety of EF-related research such as EF-cell interaction and tissue regeneration studies.

The performance of the vapor chamber based on the plant leaf

The performance of a novel vapor chamber based on the leaf vein system is tested in this study. In this vapor chamber, the conceptual structure, being composed of leaf-vein-like fractal network and micro fin-pins and used to simulate the transportation principle of plant leaf, is made on the inner surface of the top copper plate to form the wick of the condenser. To the inner surface of the bottom, a copper plate sintered with a layer of porous wick is used as the evaporator. Because the conceptual structure is not restricted by the shape, the vapor chamber is made into circular and rectangular shape respectively. In the circular vapor chamber, the supporting columns sintered with copper powder are used to strength the vapor chamber. However, in the rectangular vapor chamber, the wick of the condenser contacts directly with the wick of the evaporator so as to strength the vapor chamber and shorten the back flow length of the liquid condensed on the groove surface. In the circular vapor chamber, the fractal angle of the leaf-vein-like fractal network is 30–70°, and the vapor chamber is packaged with eight bolts for convenience. In the measurement, the vapor chamber has small thermal resistance when the fractal angle is 40° and 50°, and in the rectangular vapor chamber, the thermal resistance of the vapor chamber is about 0.06°C/W.

Multi-camera system for 3D forensic documentation

Three-dimensional (3D) surface documentation is well established in forensic documentation. The most common systems include laser scanners and surface scanners with optical 3D cameras. An additional documentation tool is photogrammetry. This article introduces the botscan© (botspot GmbH, Berlin, Germany) multi-camera system for the forensic markerless photogrammetric whole body 3D surface documentation of living persons in standing posture.We used the botscan© multi-camera system to document a person in 360°. The system has a modular design and works with 64 digital single-lens reflex (DSLR) cameras. The cameras were evenly distributed in a circular chamber. We generated 3D models from the photographs using the PhotoScan© (Agisoft LLC, St. Petersburg, Russia) software.Our results revealed that the botscan© and PhotoScan© produced 360° 3D models with detailed textures. The 3D models had very accurate geometries and could be scaled to full size with the help of scale bars.In conclusion, this multi-camera system provided a rapid and simple method for documenting the whole body of a person to generate 3D data with Photoscan©.

Methods matter: considering locomotory mode and respirometry technique when estimating metabolic rates of fishes.

Respirometry is frequently used to estimate metabolic rates and examine organismal responses to environmental change. Although a range of methodologies exists, it remains unclear whether differences in chamber design and exercise (type and duration) produce comparable results within individuals and whether the most appropriate method differs across taxa. We used a repeated-measures design to compare estimates of maximal and standard metabolic rates (MMR and SMR) in four coral reef fish species using the following three methods: (i) prolonged swimming in a traditional swimming respirometer; (ii) short-duration exhaustive chase with air exposure followed by resting respirometry; and (iii) short-duration exhaustive swimming in a circular chamber. We chose species that are steady/prolonged swimmers, using either a body-caudal fin or a median-paired fin swimming mode during routine swimming. Individual MMR estimates differed significantly depending on the method used. Swimming respirometry consistently provided the best (i.e. highest) estimate of MMR in all four species irrespective of swimming mode. Both short-duration protocols (exhaustive chase and swimming in a circular chamber) produced similar MMR estimates, which were up to 38% lower than those obtained during prolonged swimming. Furthermore, underestimates were not consistent across swimming modes or species, indicating that a general correction factor cannot be used. However, SMR estimates (upon recovery from both of the exhausting swimming methods) were consistent across both short-duration methods. Given the increasing use of metabolic data to assess organismal responses to environmental stressors, we recommend carefully considering respirometry protocols before experimentation. Specifically, results should not readily be compared across methods; discrepancies could result in misinterpretation of MMR and aerobic scope.

An Investigation of Acoustic Attenuation Performance of Silencers with Mean Flow Based on Three-Dimensional Numerical Simulation

Transmission loss (TL) is often used to evaluate the acoustic attenuation performance of a silencer. In this work, a three-dimensional (3D) finite element method (FEM) is employed to calculate the TL of some representative silencers, namely, circular expansion chamber silencer and straight-through perforated pipe silencer. In order to account for the effect of mean flow that exists inside the silencer, the 3D FEM is used in conjunction with the Computational Fluid Dynamics (CFD) simulation of the flow field. More concretely, the 3D mean flow field is computed by firstly using CFD, and then the obtained mean flow data are imported to an acoustic solution undertaken using FEM. The data transfer between the two steps is accomplished by mesh mapping. The results presented demonstrate good agreement between present TL predictions and previously published experimental and numerical works. Also, the details of the flow inside the silencers may be studied. Furthermore, the effect of mean flow velocity on acoustic attenuation performance of the silencers is investigated. It is concluded that for the studied silencers, in general, increasing flow velocity increases the TL and decreases the resonance peaks.

Analytical Prediction of Transmission Loss in Distorted Circular Chamber Mufflers With Extended Inlet/Outlet Ports by Using a Regular Perturbation Method

The sound attenuation performance in elliptic chamber mufflers with extended inlet and outlet ports is investigated in the present work. Unlike cylindrical geometries, the ellipticity of the chamber prevents development of analytical solutions in terms of the elliptic eigenfunctions. In order to overcome this geometric limitation, a perturbation-based approach is adopted through this work. For moderate chamber eccentricities, transmission loss (TL) curves derived through the perturbed eigensolutions are observed to compare well with numerical simulations. The effects of higher-order propagating modes on the TL curves, which otherwise are nonpropagating for the corresponding cylindrical chamber extended muffler are discussed. Parametric studies on different tuned duct extensions are presented to show broadband sound attenuation.