Jet Formation in Micro Post Arrays

2014 ◽  
Vol 553 ◽  
pp. 367-372
Author(s):  
Ryan S. Pawell ◽  
Robert A. Taylor ◽  
David W. Inglis ◽  
Tracie J. Barber
Keyword(s):  
Velocity Profile ◽  
Metastatic Cancer ◽  
Streamwise Velocity ◽  
Transitional Region ◽  
Jet Formation ◽  
Jet Length ◽  
Viscous Forces ◽  
Cancer Management ◽  
And Performance ◽  
Reynolds Number Flows

Micropost arrays serve as a plaform for the next generation of diagnostic devices. These arrays are found in microfluidic devices for peripheral blood-based diagnostics and metastatic cancer management. The function and performance of these devices is determined by the underlying micro-scale fluid mechanics. Typically, these devices operate in the creeping regime (Re << 1) where the viscous forces of the fluids dominate. Recent advances in manufacturing allow for higher Reynolds number flows (Re >> 1) where the inertial forces dominate. In this work, we use computational simulations to show there is a transitional region (1 < Re < 20) in between the laminar and creeping regimes for two different micropost array geometries. Numerical analysis is employed to investigate jet formation both within the array and at the array exit. The peak-to-peak amplitude of the streamwise normalized velocity profile is used to quantify jet formation within the array; the streamwise velocity profile at the end of the array exit is used to determine jet length at the exit of the array. Above the transitional region (Re > 20) significant jets form downstream of the posts, amplitude scales exponentially and jet length scales with Re according to power law.

scholarly journals Towards Routine Implementation of Liquid Biopsies in Cancer Management: It Is Always Too Early, until Suddenly It Is Too Late

Diagnostics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 103
Author(s):  
Maarten J. IJzerman ◽  
Jasper de Boer ◽  
Arun Azad ◽  
Koen Degeling ◽  
Joel Geoghegan ◽  
...  
Keyword(s):  
Clinical Utility ◽  
Clinical Laboratory ◽  
Genomic Analysis ◽  
Current Evidence ◽  
Liquid Biopsies ◽  
Blood Draw ◽  
Minimum Quality Standards ◽  
Cancer Management ◽  
Alternative Funding ◽  
And Performance

Blood-based liquid biopsies are considered a new and promising diagnostic and monitoring tool for cancer. As liquid biopsies only require a blood draw, they are non-invasive, potentially more rapid and assumed to be a less costly alternative to genomic analysis of tissue biopsies. A multi-disciplinary workshop (n = 98 registrations) was organized to discuss routine implementation of liquid biopsies in cancer management. Real-time polls were used to engage with experts’ about the current evidence of clinical utility and the barriers to implementation of liquid biopsies. Clinical, laboratory and health economics presentations were given to illustrate the opportunities and current levels of evidence, followed by three moderated break-out sessions to discuss applications. The workshop concluded that tumor-informed assays using next-generation sequencing (NGS) or PCR-based genotyping assays will most likely provide better clinical utility than tumor-agnostic assays, yet at a higher cost. For routine application, it will be essential to determine clinical utility, to define the minimum quality standards and performance of testing platforms and to ensure their use is integrated into current clinical workflows including how they complement tissue biopsies and imaging. Early health economic models may help identifying the most viable application of liquid biopsies. Alternative funding models for the translation of complex molecular diagnostics, such as liquid biopsies, may also be explored if clinical utility has been demonstrated and when their use is recommended in multi-disciplinary consensus guidelines.

scholarly journals Mathematical modelling of streamwise velocity profile in open channels using Tsallis entropy

2021 ◽  
Vol 94 ◽  
pp. 105581
Author(s):  
Manotosh Kumbhakar ◽  
Rajendra K. Ray ◽  
Suvra Kanti Chakraborty ◽  
Koeli Ghoshal ◽  
Vijay P. Singh
Keyword(s):  
Velocity Profile ◽  
Mathematical Modelling ◽  
Streamwise Velocity ◽  
Tsallis Entropy ◽  
Open Channels

Effect of Small-Amplitude Heaving Oscillations on the Flow Structure Above a Low-Aspect Ratio Wing

2011 ◽  
Author(s):  
Miguel R. Visbal
Keyword(s):  
Micro Air Vehicles ◽  
Dynamic Stall ◽  
Flapping Wings ◽  
Flight Performance ◽  
Low Reynolds Number Flows ◽  
Effective Angle ◽  
And Performance ◽  
Aerodynamic Surfaces ◽  
Reynolds Number Flows ◽  
Air Vehicles

Unsteady low-Reynolds-number flows are of importance in understanding the flight performance of natural flyers, as well as in the design of small unmanned air vehicles and micro air vehicles [1,2]. The imposed motion of flapping wings or the large excursions in effective angle of attack during gust encounters may induce the formation of dynamic-stall-like vortices [3–10] whose evolution and interaction with the aerodynamic surfaces impact both flight stability and performance.

scholarly journals Comparison of Computational Velocity and Heat Transfer Predictions to Experimental Measurements in a Rotating Cooling Passage With Smooth Walls

1999 ◽  
Author(s):  
Jeffrey P. Bons
Keyword(s):  
Heat Transfer ◽  
Velocity Profile ◽  
Density Ratio ◽  
Maximum Velocity ◽  
Streamwise Velocity ◽  
Buoyancy Effect ◽  
Wall Functions ◽  
Zonal Model ◽  
Numerical Predictions ◽  
Cooling Passage

Numerical predictions of the turbulent velocity field and wall heat transfer for a simulated turbine blade cooling passage are presented. The square cross-sectioned, smooth-walled passage is identical to one for which velocity and heat transfer data are available for comparison. Reynolds number (8000), rotation number (0.2), and buoyancy numbers (0 and 0.49) are typical of gas turbine applications. Predictions are presented for three turbulence models: standard k-ε, Renormalization Group k-ε, and Reynolds Stress. In addition, two wall treatments are evaluated: wall functions and a two-layer zonal model. Results from the three models are comparable, however the two-layer zonal wall treatment provides the best match to both the experimental flowfield data and the Nusselt distribution. Wall functions are shown to be unsuitable for this flowfield. General flow features in the passage are adequately captured by the zonal model including the Coriolis-induced double vortex and the distorted streamwise velocity profile due to the buoyancy effect. Agreement between the calculated and measured streamwise velocity profile (from leading to trailing wall) is particularly remarkable and contributes to an impressive leading and trailing Nu match with the data. This agreement suggests that the model adequately accounts for the buoyancy effect on the bulk flow without any buoyancy terms in the k or ε conservation equations. The model is less effective, however, at capturing the specific vortex position and strength. Specifically, the model vortex has only half the measured vortex maximum velocity and is located forward or aft of the passage centerline (depending on the density ratio of the flow).

Study of Shaped Charge Jet Penetration into Concrete Target

2011 ◽  
Vol 282-283 ◽  
pp. 650-653
Author(s):  
Zai Cheng Wang ◽  
Chun Lan Jiang ◽  
Ming Li
Keyword(s):  
Shaped Charge ◽  
Jet Formation ◽  
Jet Length ◽  
Simulation And Experiment ◽  
Jet Penetration ◽  
Shaped Charge Jet ◽  
Tip Velocity ◽  
Concrete Target

Based on the application of tandem weapon used to destroy concrete target this paper presents the results of simulation and experiment that investigate the penetration performance of shaped charge to runway. Jet formation and penetrating into multi-layer target was calculated by hydro code LS-DYNA3D. Jet tip velocity and jet length, also the penetration performance are studied. The damage performance of shaped charge is validated by experiment. The analysis demonstrates the shaped charge can create a big borehole for subsequent projectile to follow in.

scholarly journals Consensus document of the Italian Association of Medical Oncology and the Italian Society of Palliative Care on early palliative care

2018 ◽  
Vol 105 (2) ◽  
pp. 103-112 ◽  
Author(s):  
Domenico C. Corsi ◽  
Adriana Turriziani ◽  
Luigi Cavanna ◽  
Piero Morino ◽  
Angela S. Ribecco ◽  
...  
Keyword(s):  
Palliative Care ◽  
Medical Oncology ◽  
Metastatic Cancer ◽  
Italian Society ◽  
Cancer Prognosis ◽  
Early Palliative Care ◽  
Cancer Management ◽  
Consensus Document ◽  
Palliative Care Consultation ◽  
Practice Models

A consensus document on early palliative care was produced by a committed Working Group of the Italian Society of Medical Oncology and the Italian Society of Palliative Care to improve the early integration of palliative care in medical oncology and to stimulate and guide the choices of those who daily face the problems of advanced stage cancer patients. The simultaneous administration of antineoplastic treatments and early palliative care was shown to be beneficial in metastatic cancer pathway outcomes. Patients who could benefit from early palliative care are those with an advanced cancer at presentation, a compromised PS for cancer, and/or morbidities, and who are too frail to receive treatment. According to the Bruera practice models, in which the combination of cancer management with early palliative care can be offered, three groups of patients needing simultaneous care were identified and three different models of the delivery of palliative care were proposed. In patients with good prognosis and low need of simultaneous care, the solo practice model and the request for consultations were suggested, while in patients with poor prognosis disease with high need of simultaneous care and in conditions with high need of simultaneous care, regardless of cancer prognosis, the integrated care approach should be offered. Palliative care consultation services are seldom accessible in the majority of Italian hospitals; thus the application of various practice models depends on available resources, and a shared care model with the structures of palliative care operating in the area is often required.

scholarly journals Parabolic velocity profile causes shape-selective drift of inertial ellipsoids

2021 ◽  
Vol 926 ◽  
Author(s):  
J. Bagge ◽  
T. Rosén ◽  
F. Lundell ◽  
A.-K. Tornberg
Keyword(s):  
Velocity Profile ◽  
Rotational Inertia ◽  
Fluid Inertia ◽  
Magnus Force ◽  
Heavy Particles ◽  
Viscous Forces ◽  
Oblate Spheroids ◽  
Parabolic Velocity Profile ◽  
Order Of Magnitude ◽  
Shape Selective

Understanding particle drift in suspension flows is of the highest importance in numerous engineering applications where particles need to be separated and filtered out from the suspending fluid. Commonly known drift mechanisms such as the Magnus force, Saffman force and Segré–Silberberg effect all arise only due to inertia of the fluid, with similar effects on all non-spherical particle shapes. In this work, we present a new shape-selective lateral drift mechanism, arising from particle inertia rather than fluid inertia, for ellipsoidal particles in a parabolic velocity profile. We show that the new drift is caused by an intermittent tumbling rotational motion in the local shear flow together with translational inertia of the particle, while rotational inertia is negligible. We find that the drift is maximal when particle inertial forces are of approximately the same order of magnitude as viscous forces, and that both extremely light and extremely heavy particles have negligible drift. Furthermore, since tumbling motion is not a stable rotational state for inertial oblate spheroids (nor for spheres), this new drift only applies to prolate spheroids or tri-axial ellipsoids. Finally, the drift is compared with the effect of gravity acting in the directions parallel and normal to the flow. The new drift mechanism is stronger than gravitational effects as long as gravity is less than a critical value. The critical gravity is highest (i.e. the new drift mechanism dominates over gravitationally induced drift mechanisms) when gravity acts parallel to the flow and the particles are small.

Vorticity and Fluid Strain

1997 ◽  
Author(s):  
David Jon Furbish
Keyword(s):  
Flow Behavior ◽  
Pure Shear ◽  
Streamwise Velocity ◽  
Rotational Component ◽  
Dynamical Equations ◽  
One Dimensional ◽  
Viscous Forces ◽  
Local Rotation ◽  
Axis Of Rotation ◽  
Real Fluids

Many flows involve a sense of rotation. Clear examples include cyclones, whirlpools, and eddies. Less apparent, perhaps, is the interesting result that a one-dimensional shearing flow—for example, Couette flow—possesses a rotational component. As we will see below, the idea of fluid vorticity provides a way to characterize the rotational qualities of such flows. In addition, our treatment of vorticity will provide a way to distinguish between simple shear and pure shear of a fluid. Because shearing motions involve viscous dissipation of energy in real fluids, our descriptions of vorticity and shear will form an important part of the development of dynamical equations for flows that involve viscous forces (Chapter 12). The idea of vorticity also is useful in visualizing the onset of flow separation (Example Problem 11.4.2), very viscous flow behavior (Example Problem 12.6.5), and certain aspects of turbulence (Chapters 14 and 15). Beyond this, our treatment of vorticity is not emphasized. Let us envision a vorticity meter made of two small orthogonal vanes, with the end of one vane marked for easy identification. (Such meters can readily be constructed and used as described next.) Consider placing this meter at some position within a fluid that is rotating like a rigid body. The vorticity meter in this case rotates with the fluid in such a way that its orientation relative to the axis of rotation of the fluid remains fixed. As we will see below, the fluid possesses a definite vorticity that is reflected in the observation that the vorticity meter rotates with respect to its own axis. In this regard, we also may observe that the angular velocity of this local rotation of the meter is the same regardless of its distance from the fluid axis. Now consider a one-dimensional (Couette) shear flow. A vorticity meter placed at any position within this flow also rotates about its center due to the streamwise velocity differential over the span of the meter. Judging from the behavior of the meter, this flow also possesses a definite vorticity. We also may envision that the rate of rotation varies directly with the velocity gradient du/dy.

Esophageal Cancer—An Update Review

2013 ◽  
Vol 09 (01) ◽  
pp. 6
Author(s):  
Yang Liu ◽  
Michael K Gibson ◽  
◽  
Keyword(s):  
Quality Of Life ◽  
Esophageal Cancer ◽  
Early Stage ◽  
Metastatic Cancer ◽  
Locally Advanced ◽  
Phase Iii ◽  
Early Esophageal Cancer ◽  
Advantages And Disadvantages ◽  
Cancer Management

With the decrease of cancer incidences in a few major cancers, such as breast cancer and lung cancer, the incidence of esophageal cancer has still been climbing up steadily for the past decades, especially adenocarcinoma. Our views on esophageal cancer have been evolving as well. Modifications of the American Joint Committee on Cancer (AJCC) staging has been implemented in its recent edition in 2010. Diagnostic and follow-up standards are changing with more and more physicians and hospitals considering endoscopic ultrasound-guided biopsy as a minimal requirement for definitive diagnosis and accurate staging. In some large centers and by some physicians, laproscopic/ thorascopic biopsy are attempted to diagnose esophageal cancer with more accurate definitive staging. The widespread use of imaging studies, such as computed tomography and/or positon emission tomography, has improved the diagnosis in guiding the therapeutic options. In early stage esophageal cancer management, the acceptable modalities are still radiofrequency ablation, endoscopic mucosal resection, and photodynamic therapy. The advantages and disadvantages are discussed in this article. Surgical resection of early esophageal cancer of T2 or greater staging or N1 is still considered standard with potential to ‘cure’ while minimal invasive laproscopic surgery showed acceptable improved effects and quality of life but are still limited to some tertiary centers. Multi-modality therapies of esophageal cancer in locally advanced stage, both resectable and unresectable, are discussed in this review. For operable diseases, neoadjuvant therapy, peri-surgery therapy, adjuvant therapy, chemotherapy, and/or radiation therapy are discussed. Unresectable esophageal cancer of both adenocarcinoma and squamous cell carcinoma as well as cancer with Her2/neu expression are also considered. The attached table listed the major landmark phase III clinical trials involving esophageal carcinoma. Metastatic cancer management, including the importance of quality of life management among the survivors is also examined.

scholarly journals Feasibility of Capturing Circulating Tumor Cells With a Magnetized Device

2013 ◽  
Author(s):  
Jay D. Wheaton ◽  
Steven W. Day
Keyword(s):  
Magnetic Particles ◽  
Magnetic Force ◽  
Permanent Magnets ◽  
Metastatic Cancer ◽  
Vena Cava ◽  
Surface Protein ◽  
Ivc Filter ◽  
And Performance

Advancements in technology have led to the ability to tag virtually any cell with magnetic particles so long as the surface protein is known. In theory, these tagged cells may then be identified, imaged, or manipulated by magnetic force. In vitro separation using a magnetized stent and magnetically tagged cells was demonstrated by [1]. The motivation for this work was to investigate the feasibility of a magnetized inferior vena cava (IVC) filter for in vivo separation of metastatic cancer cells from the bloodstream. In use, the device would consist of a standard IVC filter plated with nickel, making it paramagnetic yet still biocompatible. The IVC filter is placed inside the vena cava, as is routinely done for other applications. Permanent magnets, which the patient would wear as an external vest, generate a field and the presence of the magnetized filter within this field can attract magnetic particles to the filter. In particular, our goal was to develop a numerical model that could be used to assess the feasibility and performance of such a device over a range of design space.

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