Advanced Thermal Measures of Vascular Reactivity

2017 ◽  
Author(s):  
M. Wasy Akhtar
Keyword(s):  
Flow Rate ◽  
Vascular Reactivity ◽  
Low Cost ◽  
Reactive Hyperemia ◽  
Reference Signal ◽  
Three Dimensional ◽  
External Environment ◽  
Temperature Response ◽  
Vascular Health ◽  
Finger Tip

New measures of Digital Thermal Monitoring (DTM), a low cost non-invasive tool to assess vascular health, are developed. Original measures of thermal vascular reactivity tend to be dependent upon the initial vascular state (such as temperature before occlusion). The objective of this study is to identify new measures that will provide a single independent predictor of vascular health. Full three dimensional simulations were carried out to simulate transient finger tip temperature response during brachial occlusion and reperfusion. These numerical results were validated with patient data and then used to simulate a variety of test cases and discern relationships between the thermal measure and the surge in flow rate (reactive hyperemia). Defining the zero-reactivity response as the response to a step change in flow rate from near zero back to the original steady state value before occlusion, a reference signal is constructed which accounts for the finger size, thermo-physical properties, external environment and the start temperature (initial vascular state). This reference is used to normalize the temperature reactivity, forming a new measure called adjusted temperature reactivity that is a function of reactive hyperemia only. It is independent of the initial vascular state and external environment, leading to a more robust and reliable measure of vascular health.

Sensitivity of Digital Thermal Monitoring Parameters to Reactive Hyperemia

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Mohammad W. Akhtar ◽  
Stanley J. Kleis ◽  
Ralph W. Metcalfe ◽  
Morteza Naghavi
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Vascular Reactivity ◽  
Early Stage ◽  
Reactive Hyperemia ◽  
Assessment Tools ◽  
Functional Evaluation ◽  
Thermal Monitoring ◽  
Essential Components ◽  
Baseline Flow

Both structural and functional evaluations of the endothelium exist in order to diagnose cardiovascular disease (CVD) in its asymptomatic stages. Vascular reactivity, a functional evaluation of the endothelium in response to factors such as occlusion, cold, and stress, in addition to plasma markers, is the most widely accepted test and has been found to be a better predictor of the health of the endothelium than structural assessment tools such as coronary calcium scores or carotid intima-media thickness. Among the vascular reactivity assessment techniques available, digital thermal monitoring (DTM) is a noninvasive technique that measures the recovery of fingertip temperature after 2–5 min of brachial occlusion. On release of occlusion, the finger temperature responds to the amount of blood flow rate overshoot referred to as reactive hyperemia (RH), which has been shown to correlate with vascular health. Recent clinical trials have confirmed the potential importance of DTM as an early stage predictor of CVD. Numerical simulations of a finger were carried out to establish the relationship between DTM and RH. The model finger consisted of essential components including bone, tissue, major blood vessels (macrovasculature), skin, and microvasculature. The macrovasculature was represented by a pair of arteries and veins, while the microvasculature was represented by a porous medium. The time-dependent Navier–Stokes and energy equations were numerically solved to describe the temperature distribution in and around the finger. The blood flow waveform postocclusion, an input to the numerical model, was modeled as an instantaneous overshoot in flow rate (RH) followed by an exponential decay back to baseline flow rate. Simulation results were similar to clinically measured fingertip temperature profiles in terms of basic shape, temperature variations, and time delays at time scales associated with both heat conduction and blood perfusion. The DTM parameters currently in clinical use were evaluated and their sensitivity to RH was established. Among the parameters presented, temperature rebound (TR) was shown to have the best correlation with the level of RH with good sensitivity for the range of flow rates studied. It was shown that both TR and the equilibrium start temperature (representing the baseline flow rate) are necessary to identify the amount of RH and, thus, to establish criteria for predicting the state of specific patient’s cardiovascular health.

Fabrication of 3D Temperature Sensor Using Magnetostrictive Inkjet Printhead

2020 ◽  
Vol 64 (5) ◽  
pp. 50405-1-50405-5
Author(s):  
Young-Woo Park ◽  
Myounggyu Noh
Keyword(s):  
Flexible Electronics ◽  
Inkjet Printing ◽  
Temperature Sensor ◽  
Computer Aided Design ◽  
Low Cost ◽  
Three Dimensional ◽  
Drop On Demand ◽  
Aided Design ◽  
Nanoparticle Ink ◽  
Inkjet Printhead

Abstract Recently, the three-dimensional (3D) printing technique has attracted much attention for creating objects of arbitrary shape and manufacturing. For the first time, in this work, we present the fabrication of an inkjet printed low-cost 3D temperature sensor on a 3D-shaped thermoplastic substrate suitable for packaging, flexible electronics, and other printed applications. The design, fabrication, and testing of a 3D printed temperature sensor are presented. The sensor pattern is designed using a computer-aided design program and fabricated by drop-on-demand inkjet printing using a magnetostrictive inkjet printhead at room temperature. The sensor pattern is printed using commercially available conductive silver nanoparticle ink. A moving speed of 90 mm/min is chosen to print the sensor pattern. The inkjet printed temperature sensor is demonstrated, and it is characterized by good electrical properties, exhibiting good sensitivity and linearity. The results indicate that 3D inkjet printing technology may have great potential for applications in sensor fabrication.

Constructive Optimisation of the Propeller Type Mixing Devices Using the Virtual and Rapid Prototyping

2017 ◽  
Vol 68 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Daniel Besnea ◽  
Alina Spanu ◽  
Iuliana Marlena Prodea ◽  
Gheorghita Tomescu ◽  
Iolanda Constanta Panait
Keyword(s):  
Rapid Prototyping ◽  
Low Cost ◽  
Scale Up ◽  
Three Dimensional ◽  
Rapid Identification ◽  
Multidisciplinary Optimization ◽  
External Diameter ◽  
Process Industries ◽  
Parametric Cad ◽  
Shaft Torque

The paper points out the advantages of rapid prototyping for improving the performances/constructive optimization of mixing devices used in process industries, here exemplified to propeller types ones. The multidisciplinary optimization of the propeller profile affords its design using parametric CAD methods. Starting from the mathematical curve equations proposed for the blade profile, it was determined its three-dimensional virtual model. The challenge has been focused on the variation of propeller pitch and external diameter. Three dimensional ranges were manufactured using the additive manufacturing process with Marker Boot 3D printer. The mixing performances were tested on the mixing equipment measuring the minimum rotational speed and the correspondent shaft torque for complete suspension achieved for each of the three models. The virtual and rapid prototyping method is newly proposed by the authors to obtain the basic data for scale up of the mixing systems, in the case of flexible production (of low quantities), in which both the nature and concentration of the constituents in the final product varies often. It is an efficient and low cost method for the rapid identification of the optimal mixing device configuration, which contributes to the costs reduction and to the growing of the output.

scholarly journals A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

2021 ◽  
Vol 11 (8) ◽  
pp. 3404
Author(s):  
Majid Hejazian ◽  
Eugeniu Balaur ◽  
Brian Abbey
Keyword(s):  
Molecular Dynamics ◽  
Flow Rate ◽  
Numerical Study ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Liquid Jets ◽  
Mixing Efficiency ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

scholarly journals An “Animated Spatial Time Machine” in Co-Creation: Reconstructing History Using Gamification Integrated into 3D City Modelling, 4D Web and Transmedia Storytelling

2021 ◽  
Vol 10 (7) ◽  
pp. 460
Author(s):  
Mario Matthys ◽  
Laure De Cock ◽  
John Vermaut ◽  
Nico Van de Weghe ◽  
Philippe De Maeyer
Keyword(s):  
Public Space ◽  
Low Cost ◽  
Three Dimensional ◽  
Physical Situation ◽  
Time Machine ◽  
Transmedia Storytelling ◽  
Spatial Reconstruction ◽  
3D Software ◽  
The City ◽  
City Models

More and more digital 3D city models might evolve into spatiotemporal instruments with time as the 4th dimension. For digitizing the current situation, 3D scanning and photography are suitable tools. The spatial future could be integrated using 3D drawings by public space designers and architects. The digital spatial reconstruction of lost historical environments is more complex, expensive and rarely done. Three-dimensional co-creative digital drawing with citizens’ collaboration could be a solution. In 2016, the City of Ghent (Belgium) launched the “3D city game Ghent” project with time as one of the topics, focusing on the reconstruction of disappeared environments. Ghent inhabitants modelled in open-source 3D software and added animated 3D gamification and Transmedia Storytelling, resulting in a 4D web environment and VR/AR/XR applications. This study analyses this low-cost interdisciplinary 3D co-creative process and offers a framework to enable other cities and municipalities to realise a parallel virtual universe (an animated digital twin bringing the past to life). The result of this co-creation is the start of an “Animated Spatial Time Machine” (AniSTMa), a term that was, to the best of our knowledge, never used before. This research ultimately introduces a conceptual 4D space–time diagram with a relation between the current physical situation and a growing number of 3D animated models over time.

Optimum Design for the Frame of Open Type Abrasive Flow Polish Machine

2012 ◽  
Vol 497 ◽  
pp. 89-93
Author(s):  
Liang Liang Yuan ◽  
Ke Hua Zhang ◽  
Li Min
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Finite Element Methods ◽  
Optimization Design ◽  
Low Cost ◽  
Three Dimensional ◽  
Force Model ◽  
Optimization Analysis ◽  
Open Type ◽  
Set Up

In order to process heterotype hole of workpiece precisely, an open abrasive flow polish machine is designed, and the optimization design of machine frame is done for low cost. Firstly, basing on the parameters designed with traditional ways, three-dimensional force model is set up with the soft of SolidWorks. Secondly, the statics and modal analysis for machine body have been done in Finite element methods (FEM), and then the optimization analysis of machine frame has been done. At last, the model of rebuild machine frame has been built. Result shows that the deformation angle value of machine frame increased from 0.72′ to 1.001′, the natural frequency of the machine decreased from 75.549 Hz to 62.262 Hz, the weight of machine decreased by 74.178 Kg after optimization. It meets the strength, stiffness and angel stiffness requirement of machine, reduces the weight and cost of machine.

scholarly journals Organotrialkoxysilane-Functionalized Prussian Blue Nanoparticles-Mediated Fluorescence Sensing of Arsenic(III)

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1145
Author(s):  
Prem. C. Pandey ◽  
Shubhangi Shukla ◽  
Roger J. Narayan
Keyword(s):  
Prussian Blue ◽  
Chemical Reduction ◽  
Low Cost ◽  
Three Dimensional ◽  
Heterogeneous Systems ◽  
Lattice Points ◽  
Radiative Energy ◽  
Fluorescence Sensing ◽  
Emission Signal ◽  
Prussian Blue Nanoparticles

Prussian blue nanoparticles (PBN) exhibit selective fluorescence quenching behavior with heavy metal ions; in addition, they possess characteristic oxidant properties both for liquid–liquid and liquid–solid interface catalysis. Here, we propose to study the detection and efficient removal of toxic arsenic(III) species by materializing these dual functions of PBN. A sophisticated PBN-sensitized fluorometric switching system for dosage-dependent detection of As3+ along with PBN-integrated SiO2 platforms as a column adsorbent for biphasic oxidation and elimination of As3+ have been developed. Colloidal PBN were obtained by a facile two-step process involving chemical reduction in the presence of 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane (EETMSi) and cyclohexanone as reducing agents, while heterogeneous systems were formulated via EETMSi, which triggered in situ growth of PBN inside the three-dimensional framework of silica gel and silica nanoparticles (SiO2). PBN-induced quenching of the emission signal was recorded with an As3+ concentration (0.05–1.6 ppm)-dependent fluorometric titration system, owing to the potential excitation window of PBN (at 480–500 nm), which ultimately restricts the radiative energy transfer. The detection limit for this arrangement is estimated around 0.025 ppm. Furthermore, the mesoporous and macroporous PBN-integrated SiO2 arrangements might act as stationary phase in chromatographic studies to significantly remove As3+. Besides physisorption, significant electron exchange between Fe3+/Fe2+ lattice points and As3+ ions enable complete conversion to less toxic As5+ ions with the repeated influx of mobile phase. PBN-integrated SiO2 matrices were successfully restored after segregating the target ions. This study indicates that PBN and PBN-integrated SiO2 platforms may enable straightforward and low-cost removal of arsenic from contaminated water.

scholarly journals Comparative Analysis of Digital Models of Objects of Cultural Heritage Obtained by the “3D SLS” and “SfM” Methods

2021 ◽  
Vol 11 (12) ◽  
pp. 5321
Author(s):  
Marcin Barszcz ◽  
Jerzy Montusiewicz ◽  
Magdalena Paśnikowska-Łukaszuk ◽  
Anna Sałamacha
Keyword(s):  
Cultural Heritage ◽  
Low Cost ◽  
Three Dimensional ◽  
3D Models ◽  
Silk Road ◽  
Digital Models ◽  
Global Pandemic ◽  
University Of Technology ◽  
Three Dimensional Models ◽  
3D Digitisation

In the era of the global pandemic caused by the COVID-19 virus, 3D digitisation of selected museum artefacts is becoming more and more frequent practice, but the vast majority is performed by specialised teams. The paper presents the results of comparative studies of 3D digital models of the same museum artefacts from the Silk Road area generated by two completely different technologies: Structure from Motion (SfM)—a method belonging to the so-called low-cost technologies—and by Structured-light 3D Scanning (3D SLS). Moreover, procedural differences in data acquisition and their processing to generate three-dimensional models are presented. Models built using a point cloud were created from data collected in the Afrasiyab museum in Samarkand (Uzbekistan) during “The 1st Scientific Expedition of the Lublin University of Technology to Central Asia” in 2017. Photos for creating 3D models in SfM technology were taken during a virtual expedition carried out under the “3D Digital Silk Road” program in 2021. The obtained results show that the quality of the 3D models generated with SfM differs from the models from the technology (3D SLS), but they may be placed in the galleries of the vitrual museum. The obtained models from SfM do not have information about their size, which means that they are not fully suitable for archiving purposes of cultural heritage, unlike the models from SLS.

scholarly journals Completely non-fused electron acceptor with 3D-interpenetrated crystalline structure enables efficient and stable organic solar cell

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lijiao Ma ◽  
Shaoqing Zhang ◽  
Jincheng Zhu ◽  
Jingwen Wang ◽  
Junzhen Ren ◽  
...  
Keyword(s):  
Organic Solar Cell ◽  
Low Cost ◽  
Three Dimensional ◽  
Molecular Geometry ◽  
Interpenetrating Network ◽  
Fused Ring ◽  
Molecule Design ◽  
End Capping ◽  
Conversion Efficiencies ◽  
Insight Into

AbstractNon-fullerene acceptors (NFAs) based on non-fused conjugated structures have more potential to realize low-cost organic photovoltaic (OPV) cells. However, their power conversion efficiencies (PCEs) are much lower than those of the fused-ring NFAs. Herein, a new bithiophene-based non-fused core (TT-Pi) featuring good planarity as well as large steric hindrance was designed, based on which a completely non-fused NFA, A4T-16, was developed. The single-crystal result of A4T-16 reveals that a three-dimensional interpenetrating network can be formed due to the compact π–π stacking between the adjacent end-capping groups. A high PCE of 15.2% is achieved based on PBDB-TF:A4T-16, which is the highest value for the cells based on the non-fused NFAs. Notably, the device retains ~84% of its initial PCE after 1300 h under the simulated AM 1.5 G illumination (100 mW cm−2). Overall, this work provides insight into molecule design of the non-fused NFAs from the aspect of molecular geometry control.

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