scholarly journals Infection Units: A Novel Approach for Modeling COVID-19 Spread

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2272
Author(s):  
Jose C. Merchuk ◽  
Francisco García-Camacho ◽  
Lorenzo López-Rosales

A novel mechanistic model of COVID-19 spread is presented. The pool of infected individuals is not homogeneously mixed but is viewed as a passage into which individuals enter upon the contagion, through which they pass (in the manner of “plug flow”) and exit at their recovery points within a fixed time. Our novel concept of infection unit is defined. The model separately considers various population pools: two of symptomatic and asymptomatic infected patients; three different pools of recovered individuals; of assisted hospitalized patients; of the quarantined; and of those who die from COVID-19. Transmission of this disease is described by an infection rate function, modulated by an encounter frequency function. This definition makes redundant the addition of a separate pool for the exposed, as done in several other models. Simulations are presented. The effects of social restrictions and of quarantine policies on pandemic spread are demonstrated. The model differs conceptually from others of the kind in the description of the transmission dynamics of the disease. A set of experimental data is used to calibrate our model, which predicts the dynamic behavior of each of the defined pools during pandemic spread.

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Pyrrhon Amathes ◽  
Paul Christodoulides

Photography can be used for pleasure and art but can also be used in many disciplines of science, because it captures the details of the moment and can serve as a proving tool due to the information it preserves. During the period of the Apollo program (1969 to 1972), the National Aeronautics and Space Administration (NASA) successfully landed humans on the Moon and showed hundreds of photos to the world presenting the travel and landings. This paper uses computer simulations and geometry to examine the authenticity of one such photo, namely Apollo 17 photo GPN-2000-00113. In addition, a novel approach is employed by creating an experimental scene to illustrate details and provide measurements. The crucial factors on which the geometrical analysis relies are locked in the photograph and are: (a) the apparent position of the Earth relative to the illustrated flag and (b) the point to which the shadow of the astronaut taking the photo reaches, in relation to the flagpole. The analysis and experimental data show geometrical and time mismatches, proving that the photo is a composite.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Omar Nassar ◽  
Mazin Jouda ◽  
Michael Rapp ◽  
Dario Mager ◽  
Jan G. Korvink ◽  
...  

AbstractA novel approach for automated high throughput NMR spectroscopy with improved mass-sensitivity is accomplished by integrating microfluidic technologies and micro-NMR resonators. A flow system is utilized to transport a sample of interest from outside the NMR magnet through the NMR detector, circumventing the relatively vast dead volume in the supplying tube by loading a series of individual sample plugs separated by an immiscible fluid. This dual-phase flow demands a real-time robust sensing system to track the sample position and velocities and synchronize the NMR acquisition. In this contribution, we describe an NMR probe head that possesses a microfluidic system featuring: (i) a micro saddle coil for NMR spectroscopy and (ii) a pair of interdigitated capacitive sensors flanking the NMR detector for continuous position and velocity monitoring of the plugs with respect to the NMR detector. The system was successfully tested for automating flow-based measurement in a 500 MHz NMR system, enabling high resolution spectroscopy and NMR sensitivity of 2.18 nmol s1/2 with the flow sensors in operation. The flow sensors featured sensitivity to an absolute difference of 0.2 in relative permittivity, enabling distinction between most common solvents. It was demonstrated that a fully automated NMR measurement of nine individual 120 μL samples could be done within 3.6 min or effectively 15.3 s per sample.


2002 ◽  
Vol 2002 ◽  
pp. 104-104
Author(s):  
J. A. N. Mills ◽  
E. Kebreab ◽  
L. A. Crompton ◽  
J. Dijkstra ◽  
J. France

The high contribution of postruminal starch digestion (>50%) to total tract starch digestion on certain energy dense diets (Mills et al. 1999) demands that limitations to small intestinal starch digestion are identified. Therefore, a dynamic mechanistic model of the small intestine was constructed and evaluated against published experimental data for abomasal carbohydrate infusions in the dairy cow. The mechanistic structure of the model allowed the current biological knowledge to be integrated into a system capable of identifying restrictions to dietary energy recovery from postruminal starch delivery.


SPE Journal ◽  
2013 ◽  
Vol 18 (05) ◽  
pp. 818-828 ◽  
Author(s):  
M. Hosein Kalaei ◽  
Don W. Green ◽  
G. Paul Willhite

Summary Wettability modification of solid rocks with surfactants is an important process and has the potential to recover oil from reservoirs. When wettability is altered by use of surfactant solutions, capillary pressure, relative permeabilities, and residual oil saturations change wherever the porous rock is contacted by the surfactant. In this study, a mechanistic model is described in which wettability alteration is simulated by a new empirical correlation of the contact angle with surfactant concentration developed from experimental data. This model was tested against results from experimental tests in which oil was displaced from oil-wet cores by imbibition of surfactant solutions. Quantitative agreement between the simulation results of oil displacement and experimental data from the literature was obtained. Simulation of the imbibition of surfactant solution in laboratory-scale cores with the new model demonstrated that wettability alteration is a dynamic process, which plays a significant role in history matching and prediction of oil recovery from oil-wet porous media. In these simulations, the gravity force was the primary cause of the surfactant-solution invasion of the core that changed the rock wettability toward a less oil-wet state.


2011 ◽  
Vol 15 (1) ◽  
pp. 145-158 ◽  
Author(s):  
Enzo Benanti ◽  
Cesare Freda ◽  
Vincenzo Lorefice ◽  
Giacobbe Braccio ◽  
Vinod Sharma

This work deals with the simulation of an olive pits fed rotary kiln pyrolysis plant installed in Southern Italy. The pyrolysis process was simulated by commercial software CHEMCAD. The main component of the plant, the pyrolyzer, was modelled by a Plug Flow Reactor in accordance to the kinetic laws. Products distribution and the temperature profile was calculated along reactor's axis. Simulation results have been found to fit well the experimental data of pyrolysis. Moreover, sensitivity analyses were executed to investigate the effect of biomass moisture on the pyrolysis process.


2015 ◽  
Vol 38 (6) ◽  
Author(s):  
Mandy Sowa ◽  
Kai Großmann ◽  
Juliane Scholz ◽  
Nadja Röber ◽  
Stefan Rödiger ◽  
...  

AbstractIf there is a suspicion of a systemic autoimmune disease, a two-step assessment of autoantibodies (AAb) is recommended for the serological diagnosis thereof. First, AAb will be determined using sensitive, cell-based indirect immunofluorescence. Then, a positive result must be confirmed with a more specific test due to the possibility of false-positive results. This gradual approach is necessary because there is currently no assay technique that fulfills the requirements for a one-stage procedure for sensitivity and specificity. For effective AAb analysis, simultaneous determination of several AAb with multiparametric confirmatory assays significantly shortens serological diagnosis, compared with conventional monoparametric testing. Yet, currently available multiparametric AAb detection techniques do not offer the combination of screening and confirmatory testing. Thus, a new approach based on digital fluorescence was developed by applying a novel CytoBead technology that is presented here. The aim was to combine the recommended stepwise approach consisting of sensitive screening and confirmation of specific diagnosis in a reaction environment and thereafter the possibility of adaptation to the serological diagnosis of several autoimmune diseases. Using standard microscopic glass slides and the combination of native cellular or tissue substrates with autoantigen-loaded fluorescent microparticles (beads) in a reaction environment, along with the possibility of manual and automatic evaluation by IIF and the quantitative measurement of fluorescent signals, the disadvantages of currently existing test systems could be overcome. This novel concept is applicable for the determination of various multiparametric AAb, e.g., the determination of antinuclear antibodies and the corresponding AAb in molecular cytoplasmic and nuclear autoantigenic structures. Further, this becomes the basis for the simultaneous multiparametric AAb determination for the serology of celiac disease or ANCA-associated vasculitides.


2021 ◽  
Author(s):  
Mehdi Asadollahzadeh ◽  
Rezvan Torkaman ◽  
Meisam Torab-Mostaedi ◽  
Mojtaba Saremi

Abstract The current study focuses on the recovery of zinc ions by solvent extraction in the pulsed contactor. The Zn(II) ions from chloride solution were extracted into the organic phase containing D2EHPA extractant. The resulting data were characterized for the relative amount of (a) pulsed and no-pulsed condition; and (b) flow rate of both phases. Based on the mass balance equations for the column performance description, numerical computations of mass transfer in a disc-donut column were conducted and validated the experimental data for zinc extraction. Four different models, such as plug flow, backflow, axial dispersion, and forward mixing were evaluated in this study. The results showed that the intensification of the process with the pulsed condition increased and achieved higher mass transfer rates. The forward mixing model findings based on the curve fitting approach validated well with the experimental data. The results showed that an increase in pulsation intensity, as well as the phase flow rates, have a positive impact on the performance of the extractor, whereas the enhancement of flow rate led to the reduction of the described model parameters for adverse phase.


2020 ◽  
Vol 110 (03) ◽  
pp. 130-134
Author(s):  
Michael Neubauer ◽  
Patrick Mesmer ◽  
Armin Lechler ◽  
Alexander Verl

Industrieroboter werden zunehmend für Anwendungen eingesetzt, in denen es wichtig ist, die programmierte Bahn exakt einzuhalten. Hierfür ist vorwiegend das dynamische Verhalten der Roboterachsen entscheidend. Stetig steigende Anforderungen an die dynamische Bahngenauigkeit motivieren die Analyse und Quantifizierung der Achsdynamik. In diesem Beitrag wird ein neuer Ansatz vorgestellt, bei dem das dynamische Verhalten von Roboterachsen mithilfe von Secondary Encodern ermittelt wird.   Industrial robots are increasingly used for applications with high requirements on path accuracy. The main factor here is the dynamic behavior of the robot joints. To satisfy rising demands on dynamic path accuracy, it is essential to analyze and quantify the axis dynamics. This paper presents a novel approach to determine the dynamic behavior of robot axes using secondary encoders.


2000 ◽  
Author(s):  
Vahid Jalili ◽  
Mayur K. Patel ◽  
Christopher Bailey

Abstract The aim of this paper is to report on a novel approach used in designing spacer (a biomedical device used to aid inhalation of the drug). The Computational Fluid Dynamics (CFD) technique has been around for some years, but to date has not been used in designing spacers. In the present study the commercial CFD engines used were FLUENT-5.1.1 and PHOENICS. The study covered a large area taking into account various parameter changes such as the inlet boundary condition i.e. changing the velocity at inlet, varying the jet angle at entry to the spacer and the actual length of the spacer. The results were possible were compared to the experimental data available and generally the comparison was good. The findings from this research have highlighted, that there is an optimum size of 6cm and inlet velocity of 30m/s which result in an increased efficiency. It was also found that there is an optimum time of 0.4 sec. For which the highest drug concentration appears to be present.


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