scholarly journals Facial pressure zones of an oronasal interface for noninvasive ventilation: a computer model analysis

2014 ◽  
Vol 40 (6) ◽  
pp. 652-657 ◽  
Author(s):  
Luana Souto Barros ◽  
Pedro Talaia ◽  
Marta Drummond ◽  
Renato Natal-Jorge
Keyword(s):  
Computer Simulation ◽  
Skin Lesion ◽  
Computer Model ◽  
Noninvasive Ventilation ◽  
Laser Scanning ◽  
Soft Tissues ◽  
Geometric Model ◽  
Human Face ◽  
Nasal Bridge ◽  
Nasal Cartilage

OBJECTIVE: To study the effects of an oronasal interface (OI) for noninvasive ventilation, using a three-dimensional (3D) computational model with the ability to simulate and evaluate the main pressure zones (PZs) of the OI on the human face. METHODS: We used a 3D digital model of the human face, based on a pre-established geometric model. The model simulated soft tissues, skull, and nasal cartilage. The geometric model was obtained by 3D laser scanning and post-processed for use in the model created, with the objective of separating the cushion from the frame. A computer simulation was performed to determine the pressure required in order to create the facial PZs. We obtained descriptive graphical images of the PZs and their intensity. RESULTS: For the graphical analyses of each face-OI model pair and their respective evaluations, we ran 21 simulations. The computer model identified several high-impact PZs in the nasal bridge and paranasal regions. The variation in soft tissue depth had a direct impact on the amount of pressure applied (438-724 cmH2O). CONCLUSIONS: The computer simulation results indicate that, in patients submitted to noninvasive ventilation with an OI, the probability of skin lesion is higher in the nasal bridge and paranasal regions. This methodology could increase the applicability of biomechanical research on noninvasive ventilation interfaces, providing the information needed in order to choose the interface that best minimizes the risk of skin lesion.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

The Effect of Closed Septorhinoplasty on Nasal Functions and on External and Internal Nasal Valves: A Prospective Study

2017 ◽  
Vol 31 (5) ◽  
pp. 323-327 ◽  
Author(s):  
Giancarlo Pecorari ◽  
Giuseppe Riva ◽  
Francesca Antonella Bianchi ◽  
Giovanni Cavallo ◽  
Francesca Revello ◽  
...  
Keyword(s):  
Prospective Study ◽  
Nasal Obstruction ◽  
Laser Scanning ◽  
Soft Tissues ◽  
Statistical Significance ◽  
Three Dimensional ◽  
Subjective Assessment ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Objective Reduction

Background Because nasal function and shape are so closely intertwined, quantitative assessments can better define their relationship and how they are affected by septorhinoplasty. Objective The aim of this prospective study was to perform an analysis of the nasal airflow resistances and a three-dimensional (3D) evaluation of the soft-tissue changes after closed septorhinoplasty. Methods Before surgery (TO) and 6 months after closed septorhinoplasty (Tl), 30 patients underwent symptoms evaluation by means of the Italian version of the Nasal Obstruction Symptom Evaluation scale, endoscopic fiberoptic nasal examination, and visual analog scale for subjective assessment of nasal obstruction. Nasal airflow resistances were investigated with active anterior active rhinomanometry. A 3D laser scanner was used to evaluate facial soft-tissues, with specific nasal points and angles. Results Subjective nasal obstruction decreased. Anterior active rhinomanometry demonstrated a reduction in total inspiratory and expiratory resistances between T0 and T1 but without statistical significance. The significance was still absent after decongestion, excluding turbinate hypertrophy as a cause of failed objective amelioration of nasal resistance. Facial laser scanning showed statistically significant reduction of the superior nasal width and superior alar angle, and a weak negative correlation between the superior alar angle and nasal resistances. Conclusion The absence of objective reduction of nasal airflow resistances could be the result of concurrent surgery on nasal septum and nasal valve. In particular, the ameliorating effect on nasal airflow resistances is counterbalanced by the worsening effect of the narrowing of nasal valve.

COMPUTER SIMULATION OF PROCESSES IN A DAMPED CURRENT GENERATOR

2020 ◽  
Author(s):  
A.P Sinegubov ◽  
◽  
V.A. Shelest ◽  
D.A. Kopeikin
Keyword(s):  
Computer Simulation ◽  
Computer Model ◽  
Current Generator ◽  
Mos Transistor

The article considers a damped current generator based on a MOS transistor. In the LTspice IV package, a computer model of the generator is being developed, which allows to study its operation and refine the circuit parameters.

A framework for near real-time ROM stockpile modelling to improve blending efficiency

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shi Zhao ◽  
Tien-Fu Lu ◽  
Larissa Statsenko ◽  
Benjamin Koch ◽  
Chris Garcia
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Laser Scanning ◽  
High Efficiency ◽  
Reference Model ◽  
Geometric Model ◽  
Mining Industry ◽  
Management Systems ◽  
Content Type ◽  
Ore Grade

Purpose In the mining industry, a run-of-mine (ROM) stockpile is a temporary storage unit, but it is also widely accepted as an effective method to reduce the short-term variations of ore grade. However, tracing ore grade at ROM stockpiles accurately using most current fleet management systems is challenging, due to insufficient information available in real time. This study aims to build a three-dimensional (3D) model for ROM stockpiles continuously based on fine-grained grade information through integrating data from a number of ore grade tracking sources. Design/methodology/approach Following a literature review, a framework for a new stockpile management system is proposed. In this system, near real-time high-resolution 3D ROM stockpile models are created based on dump/load locations measured from global positioning system sensors. Each stockpile model contains a group of layers which are separated by different qualities. Findings Acquiring the geometric shapes of all the layers in a stockpile and cuts made by front wheel loaders provides a better understanding about the quality and quality distribution within a stockpile when it is stacked/reclaimed. Such a ROM stockpile model can provide information on predicating ore blend quality with high accuracy and high efficiency. Furthermore, a 3D stockyard model created based on such ROM stockpile models can help organisations optimise material flow and reduce the cost. Research limitations/implications The modelling algorithm is evaluated using a laboratory scaled stockpile at this stage. The authors expect to scan a real stockpile and create a reference model from it. Meanwhile, the geometric model cannot represent slump or collapse during reclaiming faithfully. Therefore, the model is expected to be reconcile monthly using laser scanning data. Practical implications The proposed model is currently translated to the operations at OZ Minerals. The use of such model will reduce the handling costs and improve the efficiency of existing grade management systems in the mining industry. Originality/value This study provides a solution to build a near real-time high-resolution multi-layered 3D stockpile model through using currently available information and resources. Such novel and low-cost stockpile model will improve the production rates with good output product quality control.

A Microscale Collagen-Fibrin Interacting Network Model With Comparison to Experimental Results

2012 ◽  
Author(s):  
Jeffrey D. Hyypio ◽  
Mohammad F. Hadi ◽  
Victor K. Lai ◽  
Victor H. Barocas
Keyword(s):  
Mechanical Loading ◽  
Network Model ◽  
Computer Model ◽  
Soft Tissues ◽  
Uniaxial Extension ◽  
Tissue Mechanics ◽  
Experimental Results ◽  
Large Strains ◽  
Heterogeneous Nature ◽  
Engineered Tissue

Many native and bioengineered soft tissues are composed of two or more types of biopolymer networks that mechanically define and support the material [1]. Modeling the response of multi-network soft tissues to mechanical loading can be difficult due to the heterogeneous nature of these materials and the large strains (>1) involved. As tissues deform, the different biopolymer networks interact with one another and determine the overall stress-strain outcome for the tissue. Capturing this interaction could help improve the accuracy of a computer model to simulate the microscale behavior of soft tissues under load. We have developed a two-network model to reflect interactions between collagen and fibrin biopolymer networks loaded in uniaxial extension. The model can help improve our understanding of native and engineered tissue mechanics.

Computer simulation of neutrophil transit through the pulmonary capillary bed

1993 ◽  
Vol 74 (4) ◽  
pp. 1647-1652 ◽  
Author(s):  
C. C. Hanger ◽  
W. W. Wagner ◽  
S. J. Janke ◽  
T. C. Lloyd ◽  
R. L. Capen
Keyword(s):  
Computer Simulation ◽  
Computer Model ◽  
Pulmonary Circulation ◽  
Cell Deformation ◽  
In Vivo Microscopy ◽  
Pulmonary Capillaries ◽  
Pulmonary Capillary ◽  
Capillary Bed ◽  
Diameter Distributions

One-half of the neutrophils that enter the pulmonary circulation become temporarily trapped in capillaries. The neutrophils that are impeded make complete stops between free-flowing movements. These observations, based on in vivo microscopy, suggest that pulmonary margination is caused by neutrophils being impeded at focal sites in the capillary bed. To investigate the frequency with which impeding sites had to occur in the pulmonary capillaries to trap one-half of the circulating neutrophils, we developed a computer model to simulate neutrophils encountering discrete obstructions in a capillary-like network. Surprisingly, if only 1% of the capillaries in the network acted as traps, one-half of the neutrophils stopped at least once. The trapping ability of a given percentage of obstructions was independent both of the geometry of the network was whether the obstructions occurred in the segments or junctions. To simulate neutrophil transit more realistically, both neutrophil and capillary diameters were randomly selected from published diameter distributions. Every neutrophil was trapped multiple times by this model, suggesting that cell deformation contributes importantly to neutrophil passage through the pulmonary capillary bed.

An Empirical Test for Steward's Model of Great Basin Settlement Patterns

1973 ◽  
Vol 38 (2) ◽  
pp. 155-176 ◽  
Author(s):  
David Hurst Thomas
Keyword(s):  
Computer Simulation ◽  
Great Basin ◽  
Computer Model ◽  
Random Sampling ◽  
Settlement Patterns ◽  
Empirical Test ◽  
Cultural Ecology ◽  
Computer Simulation Model ◽  
Empirical Validation ◽  
Settlement System

AbstractJulian Steward's theory of Great Basin cultural ecology and settlement patterns has been subjected to empirical validation. Since the only data available to test this hypothesis are archaeological, it was first necessary to determine the artifactual correlates for the posited ethnographic system. These deductive propositions were determined by the BASIN I computer simulation model. On the basis of data obtained in a regional random sampling project in the Reese Valley of central Nevada, over 75% of the nearly 130 deductive predictions were statistically verified. The rejected propositions probably reflect failure of the computer model rather than shortcomings in Steward's theory. The archaeological manifestation of the Shoshonean pattern is defined as the Reese River Subsistence-Settlement System which operated in the central Great Basin from about 2500 B.C. to historic times.

scholarly journals SURVEY AND MODELLING FOR THE BIM OF BASILICA OF SAN MARCO IN VENICE

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 303-310 ◽  
Author(s):  
L. Fregonese ◽  
L. Taffurelli ◽  
A. Adami ◽  
S. Chiarini ◽  
S. Cremonesi ◽  
...  
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Geometric Model ◽  
Data Organization ◽  
The Public ◽  
Mesh Model ◽  
Alternative Systems ◽  
Work Units ◽  
The Church ◽  
Mesh Models

The Basilica of San Marco is a singular case in the field of Cultural heritage, as it constitutes a construction site always active for the maintenance and preservation of the basilica itself. The continuous intervention of conservation, due to the particular environmental conditions of Venice and the opening to the public, together with the complexity of the building itself, imposes the need to identify an optimized management system. For this reason, in 2013 the Procurator of St. Marco Basilica commissioned the construction of a 3D model of the Basilica to be used for the creation of a BIM. The model must meet the required precision of the scale of 1:50, and should also include, in addition to the geometric description, a description of the mosaic and marble surfaces of the basilica through high resolution orthophoto which are essential for the restoration of the mosaics. <br><br> The complexity of the church and the large and continuous flow of public led to work in non-optimal conditions especially for the acquisition stage. The basilica has certain peculiarities that led to some important choices, for example the use of photogrammetry instead of laser scanning technique. The same technique was preferred also by the need to realize, in addition to the geometric model, high-resolution orthophotos of marbles and mosaic surfaces. <br><br> The modelling of the basilica has highlighted a number of problems related to the building features. The basilica, indeed, is the result of the juxtaposition of elements (capitals, columns) with different origin, which therefore cannot be standardized in special libraries. Moreover, especially in the extensive mosaic areas, there are not edges that characterize the architecture, but only beveled surfaces. This has resulted in a change also in the modeling paradigm with the need to identify alternative systems even for the construction of simple elements. Therefore, we decided to model using NURBS since it is the method that allows greater adherence to reality and, at the same time, a model with acceptable dimensions in terms of navigation and usability. Only the most sculptural pieces such as capitals and statues have been replaced by mesh models. <br><br> As we were interested in different elaborations, the results of this work are a geometric NURBS model for the subsequent insertion into BIM environment, with the possibility of extracting two-dimensional drawings such as plans and sections, a mesh model with low resolution textures for online navigation and high resolution orthophotos. <br><br> The survey work and modeling has been almost completed for the interior of the basilica whereas only the external remains to be acquired and modeled. For the management of the entire work it was decided to use the data organization system already used by the Politecnico di Milano for the Duomo di Milano. The BIM3DSURVEY system will be essential not only to manage the finished model, but it has been very useful also during the construction phase because it allows us to divide the entire work into more work units. However, this system required some changes to meet the peculiarity of this BIM, in particular the need to append and link the orthophotos to real surfaces, in order to use the model also as a spatial index for the images.

scholarly journals Experimentation of an Information Model

2020 ◽  
Vol 5 (1) ◽  
pp. 37
Author(s):  
Adriana Rossi ◽  
Umberto Palmieri
Keyword(s):  
Phase Shift ◽  
Laser Scanning ◽  
Public Procurement ◽  
Geometric Model ◽  
Information Model ◽  
Parametric Modelling ◽  
3D Laser Scanning ◽  
Geometry Processing ◽  
Total Station

<p>Wanting to answer the questions unsolved by a previous study supported by a survey with total station, this article illustrates the results obtained with 3D laser scanning acquisitions and photo shot datasets. The precision provided by the phase shift ranging scanner technology has allowed to measure to the millimeter the deviation between the surveyed model (objective of reality, although discontinuous) and the geometric model on these data interpreted. In addition, the mathematical hypotheses useful for parametric modelling (geometry processing) are discussed. Virtualizations have been created by adopting knowledge filters and scientific tools that address to the digital (re)construction (HBIM) that allows to share and manage information and to integrate interoperable models in accordance with current public procurement regulations.</p>

scholarly journals Modeling the flow of the COVID-19 in Germany: The efficacy of lockdowns and social behavior

2020 ◽  
Author(s):  
Muhamad Khairul Bahri
Keyword(s):  
Computer Simulation ◽  
Social Behavior ◽  
Young People ◽  
System Dynamics ◽  
Computer Model ◽  
Health Workers ◽  
Uncertain Parameters ◽  
Seir Model ◽  
The Given ◽  
Death Cases

AbstractThis study develops a computer simulation in understanding the flow of the COVID-19 in Germany between January 2020 and July 2020. This aims to analyze not only the flow of the COVID-19 but also the efficacy of taken measures during the given period. The computer model is based on the SEIR concept and it is based on the system dynamics approach in which some uncertain parameters are estimated through the calibration process. Moreover, the SEIR computer model is developed by considering different flows of COVID-19 cases in older and young people in Germany. This study successfully reproduces similar patterns of infected, recovered, and death cases. Moreover, as the SEIR model can successfully reproduce similar patterns, the SEIR model can be a basis to estimate other resources such as health workers, and bed capacities.

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