Orthogonal Flow Research Articles

Study on concentration distribution and detonation characteristics of typical multiphase fuel in orthogonal flow field

The fuel concentration distribution and detonation characteristics are important for performance evaluation. In order to meet the needs of airdrop, launcher and missile, the transient flow and detonation process of multiphase fuel in orthogonal flow field are analyzed by experiments and numerical simulations. The dynamic detonation model of ethyl ether (EE), propylene oxide (PO) and tetrahydro dicyclopentadiene (JP-10) is built. The flow process, concentration distribution, overpressure, temperature and detonation wave structure of the three fuels are obtained. The results show that the falling velocity has obvious influence on the detonation process of fuel droplets. The falling velocity of 0.5 Ma makes the fuel concentration distribution more uniform and the energy output is better. The peak overpressure of EE, PO and JP-10 is 2.88 MPa, 3.21 MPa and 2.96 MPa respectively. The peak temperature is 2885 K, 3230 K and 2955 K respectively. The burn out rate increases by 8.5%, 8.1% and 13.7% respectively. JP-10 has higher sensitivity to falling velocity, and there are obvious secondary peaks of overpressure in low-speed state. PO has higher stability for falling velocity, and the scaled length of high temperature/pressure after detonation wave is 0.145 m·kg-1/3.

Bioreactor-produced iPSCs-derived dopaminergic neuron-containing neural microtissues innervate and normalize rotational bias in a dose-dependent manner in a Parkinson rat model

A breadth of preclinical studies now support the rationale of pluripotent stem cell-derived cell replacement therapies to alleviate motor symptoms in Parkinsonian patients. Replacement of the primary dysfunctional cell population in the disease, i.e. the A9 dopaminergic neurons, is the major focus of these therapies. To achieve this, most therapeutical approaches involve grafting single-cell suspensions of DA progenitors. However, most cells die during the transplantation process, as cells face anoïkis. One potential solution to address this challenge is to graft solid preparations, i.e. adopting a 3D format. Cryopreserving such a format remains a major hurdle and is not exempt from causing delays in the time to effect, as observed with cryopreserved single-cell DA progenitors. Here, we used a high-throughput cell-encapsulation technology coupled with bioreactors to provide a 3D culture environment enabling the directed differentiation of hiPSCs into neural microtissues. The proper patterning of these neural microtissues into a midbrain identity was confirmed using orthogonal methods, including qPCR, RNAseq, flow cytometry and immunofluorescent microscopy. The efficacy of the neural microtissues was demonstrated in a dose-dependent manner using a Parkinsonian rat model. The survival of the cells was confirmed by post-mortem histological analysis, characterised by the presence of human dopaminergic neurons projecting into the host striatum. The work reported here is the first bioproduction of a cell therapy for Parkinson's disease in a scalable bioreactor, leading to a full behavioural recovery 16 weeks after transplantation using cryopreserved 3D format.

New characterization of Robertson–Walker geometries involving a single timelike curve

Abstract Our aim in this paper is two-fold. We establish a novel geometric characterization of the Robertson–Walker (RW) spacetime and, along the process, we find a canonical form of the RW metric associated to an arbitrary timelike curve and an arbitrary space frame. A known characterization establishes that a spacetime foliated by constant curvature leaves whose orthogonal flow (the cosmological flow) is geodesic, shear-free, and with constant expansion on each leaf, is RW. We generalize this characterization by relaxing the condition on the expansion. We show it suffices to demand that the spatial gradient and Laplacian of the cosmological expansion on a single arbitrary timelike curve vanish. In General Relativity these local conditions are equivalent to demanding that the energy flux measured by the cosmological flow, as well as its divergence, are zero on a single arbitrary timelike curve. The proof allows us to construct canonically adapted coordinates to the arbitrary curve, thus well-fitted to an observer with an arbitrary motion with respect to the cosmological flow.

A tensorial energy-release-rate based anisotropic damage-plasticity model for concrete

This paper proposes an anisotropic damage model for concrete to capture its plasticity and damage behavior effectively. Utilizing the framework of continuum damage mechanics, the model considers the influence of plastic Helmholtz free energy on damage evolution. This approach explicitly deduces damage-related thermodynamic forces without resorting to assumptions such as strain equivalence or energy equivalence. The proposed model employs tensile and compressive damage tensors to describe the development of anisotropic damage in concrete. The solution for plastic strain utilizes the empirical plasticity model. Furthermore, a unified evolutionary criterion for isotropic and anisotropic damage is also established, incorporating damage yield functions and orthogonal flow laws. Numerical simulations are conducted to validate the model’s ability to reproduce typical nonlinear behaviors of concrete structures under various load conditions.

A fluvial‐aeolian system in response to aridification during the Late Mesozoic, Junggar Basin, Central Asia

AbstractAridification of Central Asia in the Late Mesozoic led to drastic environmental changes characterized by widespread aeolian deposits. We systematically investigated fluvial‐aeolian deposits in the Middle Jurassic Toutunhe Formation, Upper Jurassic Kalazha Formation, and Lower Cretaceous Tugulu Group in the Junggar Basin to the north of the Tianshan Orogenic Belt via unmanned aerial vehicle‐based photogrammetry, scanning electron microscope, grain‐size analysis, and detrital zircon geochronology. Paludal and deltaic environments transitioned to a fluvial‐aeolian environment from the late Middle Jurassic to the Late Jurassic. Fan delta and incisive braided river deposits accumulated in the earliest Cretaceous and evolved into a lacustrine environment with aeolian deposits in the lakeshore. Aeolian deposits are characterized by moderate‐ to well‐sorted and subangular to subround sandstones with large‐scale, high‐dip cross‐bedding, inversely graded lamination, dominant saltation grains, crescent‐shaped, and dish‐shaped impact structures. Aeolian deposits contain heavy minerals including more ilmenite, zircon, garnet, and, tourmaline and less magnetite and epidote than the fluvial deposits. The preserved aeolian sediments of the Kalazha Formation extend west–east for more than 100 km, suggesting a wide desert area during the latest Jurassic. The detrital zircon age patterns indicate that the provenance of the aeolian deposits was similar to that of coeval fluvial deposits. The cooccurrence of fluvial and aeolian deposits and the similar provenances but orthogonal flow directions indicate that the aeolian deposits were mainly sourced from the nearby fluvial material within the basin. The evolution of the fluvial‐aeolian system responded to a complete base‐level cycle controlled by the aridification and tectonics. Due to decreased sediment supply caused by aridification, the base level rose, leading to the change from braided rivers to meandering rivers, along with the deposition of aeolian sediments. Due to the tectonic reactivation in the Late Jurassic, the base level fell, causing the occurrence of alluvial fans and the expansion of the aeolian sediments. Previous studies revealed that the Tianshan in the Jurassic exhibited low relief. The fluvial‐aeolian system played an important role in maintaining the limited relief in southern Central Asia.

A biomimetic orthogonal flow sensor based on an asymmetric optical fiber sensory structure for marine sensing

With increasing attention on the world’s oceans, a significant amount of research has been focused on the sensing of marine-related parameters in recent years. In this paper, a bioinspired flow sensor with corrosion resistance, anti-interference capability, a portable design structure, easy integration, and directional sensing ability is presented to realize flow speed sensing in open water. The sensor is realized by a flexible artificial cupula that seals one side of an optical fiber acting as an artificial kinocilium. Below the artificial kinocilium, an encapsulated s-tapered optical fiber mimics the fish neuromast sensory mechanism and is supported by a 3D-printed structure that acts as the artificial supporting cell. To characterize the sensor, the optical transmission spectra of the sensory fiber under a set of water flow velocities and four orthogonal directions were monitored. The sensor’s peak intensity responses were found to demonstrate flow sensing ability for velocity and direction, proving that this biomimetic portable sensing structure is a promising candidate for flow sensing in marine environments.

Mathematical modelling of a slow flameless combustion of a two-dimensional paper

We present a mathematical model for the slow combustion (smoldering) of a two-dimensional sheet of paper. We describe the evolution of the char region, and we investigate the effects of an orthogonal air flow on the shape of the combustion front. The mathematical formulation consists in a set of two nonlinear PDEs for the temperature and the oxygen concentrations coupled with one ODE for the cellulose concentration. The (dimensionless) problem is solved numerically by means of a spectral collocation scheme based on Chebyshev polynomials. Our results show that the Péclet and the Lewis number strongly influence the shape of the ignition front and that the advancement of the combustion front does not occur if advection and diffusion are neglected (zero Péclet and Lewis numbers). In particular we observe that the burning region and the ignition front are strongly influenced by the velocity of the airflow and by the mass and heat transport phenomena due to diffusion and advection. We shall see that the increasing of the ratio between the convective and diffusive characteristic times (Péclet number) and the decreasing of the ratio between the mass and heat diffusive characteristic times (Lewis number) have a “flattening effect” on the combustion front.

The orthogonal flows for orthogonal iteration

In the field of scientific computation, orthogonal iteration is an essential method for computing the invariant subspace corresponding to the largest r eigenvalues. In this paper, we construct a flow that connects the sequence of matrices generated by the orthogonal iteration. Such a flow is called an orthogonal flow. In addition, we show that the orthogonal iteration forms a time-one mapping of the orthogonal flow. A generalized orthogonal flow is constructed that has the same column space as the orthogonal flow. By using a suitable change of variables, the generalized orthogonal flow can be transformed into the solution of a Riccati differential equation (RDE). Conversely, an RDE can also be transformed into a flow that can be represented by a generalized orthogonal flow.

A thin layer lubricant surface applications due to nonlinear radiated hybrid nanoparticles with orthogonal stagnation point flow

ABSTRACT The improved thermal association of heat transfer is considerably observed due to hybrid nanoparticles. Being to suspension of base fluids with two distinct nanoparticles, the stable properties of hybrid nanofluids are measured. Current contribution reports the enhancement in thermal impact of water (base liquid) uniformly decomposed with hybrid nanoparticles theoretically. The hybrid nanofluid properties are justified with copper and aluminum oxide nanoparticles. With improved heat transfer mechanism, the motivations for observing the aspect of lubrication phenomenon in the vicinity of stagnation points are associated to the manufacturing systems and chemical processes ample applications in fluid bearing, assembling of thin films, coating and printing. Moreover, the treatment of heat transfer is further influenced by nonlinear radiation and mixed convection applications. The dimensionless variables successfully transformed the system into a dimensionless form, which is further solved using the Keller box method. The comparative heating transfer onsets are predicted for the traditional nanofluid with suspension and hybrid nanofluid with decomposition. The results show that the lubrication phenomenon controls the wall shear force while enhancement in Nusselt number is noticed. Increasing observations for skin friction and Nusselt number are resulted for hybrid nanofluid as compared to simple nanofluid.

A study of the time fractional Navier-Stokes equations for vertical flow

<abstract><p>Navier-Stokes (NS) equations dealing with gravitational force with time-fractional derivatives are discussed in this paper. These equations can be used to predict fluid velocity and pressure for a given geometry. This paper investigates the local and global existence and uniqueness of mild solutions to NS equations for the time fractional differential operator. We also work on the regularity effects of such types of equations were caused by orthogonal flow.</p></abstract>

Digital image analysis for biothreat detection via rapid centrifugal microfluidic orthogonal flow immunocapture.

We report clear proof-of-principle for centrifugally-driven, multiplexed, paper-based orthogonal flow sandwich-style immunocapture (cOFI) and colorimetric detection of Zaire Ebola virus-like particles. Capture antibodies are immobilized onto nanoporous nitrocellulose membranes that are then laminated into polymeric microfluidic discs to yield ready-to-use analytical devices. Fluid flow is controlled solely by rotational speed, obviating the need for complex pneumatic pumping systems, and providing more precise flow control than with the capillary-driven flow used in traditional lateral flow immunoassays (LFIs). Samples containing the antigen of interest and gold nanoparticle-labeled detection antibodies are pumped centrifugally through the embedded, prefunctionalized membrane where they are subsequently captured to generate a positive, colorimetric signal. When compared to the equivalent LFI counterparts, this cOFI approach generated immunochromatographic colorimetric responses that are objectively darker (saturation), more intense (grayscale), and less variable regarding total area of the color response. We also describe an image analysis approach that enables access to rich color data and area statistics without the need for a commercial 'strip reader' or custom-written image analysis algorithms. Instead, our analytical method exploits inexpensive equipment (e.g., smart phone, flatbed scanner, etc.) and freely available software (Fiji distribution of ImageJ) to permit characterization of immunochromatographic responses that includes multiple color metrics, offering insights beyond typical grayscale analysis. The findings reported here stand as clear proof-of-principle for the feasibility of disc-based, centrifugally driven orthogonal flow through a membrane with immunocapture (cOFI) and colorimetric readout of a sandwich-type immunoassay in less than 15 minutes. Once fully developed, this cOFI platform could render a faster, more accurate diagnosis, while processing multiple samples simul-taneously.

Method for simultaneous measurement of velocity and direction of fluid flow using fiber Bragg gratings

This work is devoted to the development and research of a new optical method for measuring the velocity of a fluid flow and determining the orthogonal directions of such a flow. Comparing with gas flow, measuring the fluid flow rate requires higher heating power and insulation, which is taken into account in this work. The standard hot-wire anemometry method is taken as a basis, but instead of a metal thread, optical fiber is used for measurements. The article presents the design of a sensitive element consisting of two optical fibers. The first fiber contains an array of fiber Bragg gratings and is used as a measurement element. The second fiber has a region with a tapered structure and is used to create a heated area. Velocity measurements are given for the range of 0.02–0.05 m/s, but are limited only by the capabilities of the measuring stand. A unique method for identifying the orthogonal flow direction, which has not been described in the literature before, is presented. Differences in the shapes of the curves for the dependences of flow rates moving in the direction and orthogonally to the axis of the sensitive element are presented. The stability of the device is also confirmed by continuous experiments for 70 min.

Local and Global Canonical Forms for Differential-Algebraic Equations with Symmetries

Linear time-varying differential-algebraic equations with symmetries are studied. The structures that we address are self-adjoint and skew-adjoint systems. Local and global canonical forms under congruence are presented and used to classify the geometric properties of the flow associated with the differential equation as symplectic or generalized orthogonal flow. As applications, the results are applied to the analysis of dissipative Hamiltonian systems arising from circuit simulation and incompressible flow.

An analysis of three XCT-based methods to determine the intrinsic permeability of soil aggregates

• Consistent permeability found in orthogonal flow directions by fluid flow simulation. • Skeletonization was a reliable and quick approach to parametrize Kozeny-Carman. • Pore network modelling was more sensitive to thin ramifications of the pore system. • Faster calibrated XCT-based methods can be used in large datasets for permeability. Nowadays there are many papers dealing with the analysis of the soil porous system through X-ray computed tomography (XCT). However, a reduced number of studies focus on modeling the intrinsic permeability (k) of complex porous media, such as soil, based on three-dimensional (3D) high-resolution images. The determination of k is fundamental to understanding several processes taking place in soil such as water and air transmission. Thus, this paper compares three XCT-based methods for estimating the k of the pore system of soil aggregates: i) Finite volume-based simulation (APES - Absolute Permeability Experiment Simulation), ii) Image-based parametrization of the Kozeny-Carman (IBP-KC) equation, and iii) Pore network model (PNM). The 3D image considered in the comparison of methods was acquired at the X-ray microtomography beamline at the Brazilian Synchrotron Light Facility, with a voxel size of 1.64 μm. APES was considered as a reference method for being less dependent on the configuration of sensitivity parameters. APES and PNM demonstrated to be more time consuming than the IBP-KC, the first taking longer among all for the k computation. PNM presented the drawback of higher sensitivity to thin pore ramifications, resulting in unrealistic values of k and requiring disconnecting one thinner pore to yield permeabilities comparable to the ones obtained by APES. This study demonstrated that a fine alternative to compute k for large image datasets is to calibrate faster methods (e.g., IBP-KC and PNM) against a slower but more reliable reference method (e.g., APES), using at least one 3D image, before applying the faster methods on the remaining images of the dataset.

Orthogonal optimization for effective classification of different tea leaves by a novel pressure stabilized inclined chamber classifier

AbstractIn the field of tea separation and processing, modern high‐tech can realize the nondestructive separation of tea and improve the quality of tea. In this study, a novel pressure‐stabilizing inclined chamber classifier was proposed, which was used to adjust the particle size distribution of tea at the entrance of the classifier. A suitable cavity can control the change of wind speed so that tea leaves are not easy to bend and deform, and the success rate of grading is improved. Second, three parameters that affect the success rate of tea classification are put forward: suction wind speed V, suction distance H, and suction distance L. When the parameters are V = 6 m/s, H = 40 mm, and L = 20 mm, the best response value is obtained, thus the most suitable entrance shape is obtained. Finally, the internal flow field of the classifier is analyzed, and different sizes of tea leaves are classified according to the change of air pressure flowing through the closed structure cavity. With the distribution of air velocity, tea leaves fall into collectors with different widths. Therefore, the flow field simulation test shows that the classifier can classify high‐quality tea according to the airflow. The model lays a foundation for further study of the fluid–solid coupling process and interaction between particles.Practical ApplicationsIn this study, a novel pressure‐stabilized inclined chamber classifier was designed, and three parameters that affect the success rate of tea classification were put forward. The process conditions were optimized by orthogonal tests, and the number of experiments was reduced. This method can be used to evaluate the influence of various technological parameters on tea classification. In order to improve the classification success rate, it is necessary to statistically discuss the results of the orthogonal test and flow field analysis.

Characterization of a Centrifugal Microfluidic Orthogonal Flow Platform.

To bring to bear the power of centrifugal microfluidics on vertical flow immunoassays, control of flow orthogonally through nanoporous membranes is essential. The on-disc approach described here leverages the rapid print-cut-laminate (PCL) disc fabrication and prototyping method to create a permanent seal between disc materials and embedded nanoporous membranes. Rotational forces drive fluid flow, replacing capillary action, and complex pneumatic pumping systems. Adjacent microfluidic features form a flow path that directs fluid orthogonally (vertically) through these embedded membranes during assay execution. This method for membrane incorporation circumvents the need for solvents (e.g., acetone) to create the membrane-disc bond and sidesteps issues related to undesirable bypass flow. In other recently published work, we described an orthogonal flow (OF) platform that exploited embedded membranes for automation of enzyme-linked immunosorbent assays (ELISAs). Here, we more fully characterize flow patterns and cellulosic membrane behavior within the centrifugal orthogonal flow (cOF) format. Specifically, high-speed videography studies demonstrate that sample volume, membrane pore size, and ionic composition of the sample matrix significantly impact membrane behavior, and consequently fluid drainage profiles, especially when cellulosic membranes are used. Finally, prototype discs are used to demonstrate proof-of-principle for sandwich-type antigen capture and immunodetection within the cOF system.

Laminar Mixing in Corotating Disk Processors

Abstract Qualitative and quantitative studies of laminar mixing in a corotating disk processor chamber were carried out experimentally and theoretically. Theoretical study of the flow field in a parallel chamber indicates the presence of an orthogonal circulation flow pattern with a double circulation pattern at constant radii. A color tracer was used for studying experimentally the laminar mixing. The experiments verified the theoretically predicted flow fields and showed that the two orthogonal flow patterns bring about a composition randomization throughout the volume. Quantitative measurement of interfacial area evolution helped in characterizing the laminar mixing behaviour of such a configuration.

Orthogonal redox and optical stimuli can induce independent responses for catechol-chitosan films

Top-down measurements of catechol films show orthogonal energy flow via redox and optical modalities. These molecular electronic properties enable communication through both short-range redox modalities and long-range electromagnetic modalities.

Cooperative Active Power Management in Multifrequency Microgrid With an Energy Storage System Based on Distance of Source to Load

A multifrequency microgrid (MFMG), which has different frequency voltages and currents on the multifrequency (MF) bus can be constructed based on superposition theorem, orthogonal power flow theory, and frequency selective power transmission criteria. It is a unique system where different frequency powers are present on the bus and all active powers maintain orthogonality by flowing simultaneously through a conductor without mixing. Due to the uncertainty and intermittency of renewable sources, an energy storage system (ESS) needs to be installed with MFMG to maintain stability and reliability. The ESS will be charged/discharged based on different frequency active power imbalances in the MF bus. Due to the presence of different frequency voltages and currents on the MF bus, the integration of ESS with MFMG is challenging but not yet discussed in any literature. In this paper, an architecture of MFMG is proposed with ESS. It is found that different new power imbalance cases arise in MFMG due to different frequency sources and loads, which are not present in traditional microgrids. Here, active power balancing conditions for all power imbalance cases are defined for grid connected and islanded mode. An algorithm is proposed to coordinate the ESS and different renewable sources to balance different frequency active power demands in MFMG for optimum power generation through communication under a cooperative framework. The framework is created based on the assumption that any load prefers to take power from the nearest source to minimize the power loss and cost. Different source load pairs are categorized based on the physical distance by different frequencies and accordingly the algorithm is structured. Finally, Matlab simulation of a sample 9 bus MFMG is performed to validate the algorithm and all results are presented.

Live cell molecular analysis of primary prostate cancer organoids identifies persistent androgen receptor signaling

Prostate Cancer (PC) is a disease with remarkable tumor heterogeneity that often manifests in significant intra-patient variability with regards to clinical outcomes and treatment response. Commonly available PC cell lines do not accurately reflect the complexity of this disease and there is critical need for development of new models to recapitulate the intricate hierarchy of tumor pathogenesis. In current study, we established ex vivo primary patient-derived cancer organoid (PDCO) cultures from prostatectomy specimens of patients with locally advanced PC. We then performed a comprehensive multi-parameter characterization of the cellular composition utilizing a novel approach for live-cell staining and direct imaging in the integrated microfluidic Stacks device. Using orthogonal flow cytometry analysis, we demonstrate that primary PDCOs maintain distinct subsets of epithelial cells throughout culture and that these cells conserve expression of androgen receptor (AR)-related elements. Furthermore, to confirm the tumor-origin of the PDCOs we have analyzed the expression of PC-associated epigenetic biomarkers including promoter methylation of the GSTP1, RASSF1 and APC and RARb genes by employing a novel microfluidic rare-event screening protocol. These results demonstrate that this ex vivo PDCO model recapitulates the complexity of the epithelial tumor microenvironment of multifocal PC using orthogonal analyses. Furthermore, we propose to leverage the Stacks microfluidic device as a high-throughput, translational platform to interrogate phenotypic and molecular endpoints with the capacity to incorporate a complex tumor microenvironment.