Simulation of Anthrax Spore Transport and Inactivation in a Room: Scaling Analysis

Fluids Engineering ◽

10.1115/imece2005-83008 ◽

2005 ◽

Author(s):

Sankalp Soni ◽

Bakhtier Farouk ◽

Charles N. Haas

Keyword(s):

Ventilation Rate ◽

Injection Rate ◽

Circulation System ◽

Scaling Analysis ◽

Anthrax Spore ◽

Disinfection Process ◽

Spore Release ◽

Anthrax Spores ◽

Quantitative Understanding ◽

The Impact

Decontamination of large indoor spaces and buildings following release of biological agents is challenging, as the response to the fall 2001 anthrax-release events indicate. The ability to efficiently and rapidly decontaminate rooms/buildings is limited by the lack of quantitative understanding of the behavior of agent transport, and decontaminants. In response to any new releases it would be necessary to rapidly determine the optimal way to decontaminate the enclosed spaces. In the present study, we numerically simulate a biological agent (anthrax spores) transport and its inactivation by a decontaminant (chlorine dioxide). Such simulations can help us in deciding on decontamination strategies and also in better designs of the buildings and the associated air circulation system to minimize the risks in case of potential agent release. Furthermore, the study also determines the impact of scaling on predicted behavior of the agent distribution and disinfection process. From numerical simulations, a relationship for the inactivation time is obtained as a function of room geometry, ventilation rate, initial number of anthrax spore release, disinfectant injection rate and reaction kinetics. Such a relationship would help in determining decontamination strategies and in optimization of the decontamination processes.

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Impact of injection rate ramp-up on nucleation and arrest of dynamic fault slip

Geomechanics and Geophysics for Geo-Energy and Geo-Resources ◽

10.1007/s40948-021-00336-4 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

F. Ciardo ◽

A. P. Rinaldi

Keyword(s):

Time Scale ◽

Injection Rate ◽

Scaling Analysis ◽

Dynamic Rupture ◽

Nucleation Time ◽

Constant Rate ◽

Pressurization Rate ◽

Geological Discontinuities ◽

The Impact ◽

Dynamic Slip

AbstractFluid injection into underground formations reactivates preexisting geological discontinuities such as faults or fractures. In this work, we investigate the impact of injection rate ramp-up present in many standard injection protocols on the nucleation and potential arrest of dynamic slip along a planar pressurized fault. We assume a linear increasing function of injection rate with time, up to a given time $$t_c$$ t c after which a maximum value $$Q_m$$ Q m is achieved. Under the assumption of negligible shear-induced dilatancy and impermeable host medium, we solve numerically the coupled hydro-mechanical model and explore the different slip regimes identified via scaling analysis. We show that in the limit when fluid diffusion time scale $$t_w$$ t w is much larger than the ramp-up time scale $$t_c$$ t c , slip on an ultimately stable fault is essentially driven by pressurization at constant rate. Vice versa, in the limit when $$t_c/t_w \gg 1$$ t c / t w ≫ 1 , the pressurization rate, quantified by the dimensionless ratio $$\dfrac{Q_m t_w}{t_c Q^*}$$ Q m t w t c Q ∗ with $$Q^*$$ Q ∗ being a characteristic injection rate scale, does impact both nucleation time and arrest distance of dynamic slip. Indeed, for a given initial fault loading condition and frictional weakening property, lower pressurization rates delay the nucleation of a finite-sized dynamic event and increase the corresponding run-out distance approximately proportional to $$\propto \left( \dfrac{Q_m t_w}{t_c Q^*}\right) ^{-0.472}$$ ∝ Q m t w t c Q ∗ - 0.472 . On critically stressed faults, instead, the ramp-up of injection rate activates quasi-static slip which quickly turn into a run-away dynamic rupture. Its nucleation time decreases non-linearly with increasing value of $$\dfrac{Q_m t_w}{t_c Q^*}$$ Q m t w t c Q ∗ and it may precede (or not) the one associated with fault pressurization at constant rate only.

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Impact of injection rate ramp-up on nucleation and arrest of dynamic fault slip

10.31223/x52g8w ◽

2021 ◽

Author(s):

Federico Ciardo ◽

Antonio Pio Rinaldi

Keyword(s):

Time Scale ◽

Injection Rate ◽

Scaling Analysis ◽

Dynamic Rupture ◽

Nucleation Time ◽

Constant Rate ◽

Pressurization Rate ◽

Geological Discontinuities ◽

The Impact ◽

Dynamic Slip

Fluid injection into underground formations reactivates preexisting geological discontinuities such as faults or fractures. In this work, we investigate the impact of injection rate ramp-up present in many standard injection protocols on the nucleation and potential arrest of dynamic slip along a planar pressurized fault. We assume a linear increasing function of injection rate with time, up to a given time tc after which a maximum value Qm is achieved. Under the assumption of negligible shear-induced dilatancy and impermeable host medium, we solve numerically the coupled hydro-mechanical model and explore the different slip regimes identified via scaling analysis. We show that in the limit when fluid diffusion time scale tw is much larger than the ramp-up time scale tc, slip on an ultimately stable fault is essentially driven by pressurization at constant rate. Vice versa, in the limit when tc/tw ≫ 1, the pressurization rate, quantified by the dimensionless ratio (Qm tw / tc Q∗), does impact both nucleation time and arrest distance of dynamic slip. Indeed, for a given initial fault loading condition and frictional weakening property, lower pressurization rates delay the nucleation of a finite-sized dynamic event and increase the corresponding run-out distance approximately proportional to (Qm tw / tc Q∗)^(-0.472). On critically stressed faults, instead, the ramp-up of injection rate activates quasi-static slip which quickly turn into a run-away dynamic rupture. Its nucleation time decreases non-linearly with increasing value of (Qm tw / tc Q∗) and it may precede (or not) the one associated with fault pressurization at constant rate only.

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The Early Days of Personal Solar Ultraviolet Dosimetry

Atmosphere ◽

10.3390/atmos11020125 ◽

2020 ◽

Vol 11 (2) ◽

pp. 125 ◽

Cited By ~ 3

Author(s):

Brian Diffey

Keyword(s):

Uv Radiation ◽

Human Exposure ◽

Ground Level ◽

Uv Exposure ◽

Population Exposure ◽

Atmospheric Ozone ◽

Quantitative Understanding ◽

Solar Uv ◽

The Impact ◽

Solar Ultraviolet

In the early 1970s, environmental conservationists were becoming concerned that a reduction in the thickness of the atmospheric ozone layer would lead to increased levels of ultraviolet (UV) radiation at ground level, resulting in higher population exposure to UV and subsequent harm, especially a rise in skin cancer. At the time, no measurements had been reported on the normal levels of solar UV radiation which populations received in their usual environment, so this lack of data, coupled with increasing concerns about the impact to human health, led to the development of simple devices that monitored personal UV exposure. The first and most widely used UV dosimeter was the polymer film, polysulphone, and this review describes its properties and some of the pioneering studies using the dosimeter that led to a quantitative understanding of human exposure to sunlight in a variety of behavioral, occupational, and geographical settings.

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The New Flow Control Devices Autonomously Controlling the Performance of Matrix Acid Stimulation Operations in Carbonate Reservoirs

10.2118/205975-ms ◽

2021 ◽

Author(s):

Mojtaba Moradi ◽

Michael R Konopczynski

Keyword(s):

Flow Control ◽

Dynamic Change ◽

Injection Rate ◽

Control Flow ◽

Carbonate Reservoir ◽

Operating Conditions ◽

Carbonate Reservoirs ◽

High Permeability ◽

The Impact ◽

Stimulation Of

Abstract Matrix acidizing is a common but complex stimulation treatment that could significantly improve production/injection rate, particularly in carbonate reservoirs. However, the desired improvement in all zones of the well by such operation may not be achieved due to existing and/or developing reservoir heterogeneity. This paper describes how a new flow control device (FCD) previously used to control water injection in long horizontal wells can also be used to improve the conformance of acid stimulation in carbonate reservoirs. Acid stimulation of a carbonate reservoir is a positive feedback process. Acid preferentially takes the least resistant path, an area with higher permeability or low skin. Once acid reacts with the formation, the injectivity in that zone increases, resulting in further preferential injection in the stimulated zone. Over-treating a high permeability zone results in poor distribution of acid to low permeability zones. Mechanical, chemical or foam diversions have been used to improve stimulation conformance along the wellbore, however, they may fail in carbonate reservoirs with natural fractures where fracture injectivity dominates the stimulation process. A new FCD has been developed to autonomously control flow and provide mechanical diversion during matrix stimulation. Once a predefined upper limit flowrate is reached at a zone, the valve autonomously closes. This eliminates the impact of thief zone on acid injection conformance and maintains a prescribed acid distribution. Like other FCDs, this device is installed in several compartments in the wells. The device has two operating conditions, one, as a passive outflow control valve, and two, as a barrier when the flow rate through the valve exceeds a designed limit, analogous to an electrical circuit breaker. Once a zone has been sufficiently stimulated by the acid and the injection rate in that zone exceeds the device trip point, the device in that zone closes and restricts further stimulation. Acid can then flow to and stimulate other zones This process can be repeated later in well life to re-stimulate zones. This performance enables the operators to minimise the impacts of high permeability zones on the acid conformance and to autonomously react to a dynamic change in reservoirs properties, specifically the growth of wormholes. The device can be installed as part of lower completions in both injection and production wells. It can be retrofitted in existing completions or be used in a retrievable completion. This technology allows repeat stimulation of carbonate reservoirs, providing mechanical diversion without the need for coiled tubing or other complex intervention. This paper will briefly present an overview of the device performance, flow loop testing and some results from numerical modelling. The paper also discusses the completion design workflow in carbonates reservoirs.

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A Data Driven Change-point Epidemic Model for Assessing the Impact of Large Gathering and Subsequent Movement Control Order on COVID-19 Spread in Malaysia

10.1101/2020.11.20.20233890 ◽

2020 ◽

Author(s):

Sarat C. Dass ◽

Wai M. Kwok ◽

Gavin J. Gibson ◽

Balvinder S. Gill ◽

Bala M. Sundram ◽

...

Keyword(s):

Change Point ◽

Movement Control ◽

Disease Spread ◽

Time Period ◽

Before And After ◽

Quantitative Understanding ◽

Control Order ◽

Short Time ◽

The Impact ◽

Second Wave

AbstractThe second wave of COVID-19 in Malaysia is largely attributed to a mass gathering held in Sri Petaling between February 27, 2020 and March 1, 2020, which contributed to an exponential rise of COVID-19 cases in the country. Starting March 18, 2020, the Malaysian government introduced four consecutive phases of a Movement Control Order (MCO) to stem the spread of COVID-19. The MCO was implemented through various non-pharmaceutical interventions (NPIs). The reported number of cases reached its peak by the first week of April and then started to reduce, hence proving the effectiveness of the MCO. To gain a quantitative understanding of the effect of MCO on the dynamics of COVID-19, this paper develops a class of mathematical models to capture the disease spread before and after MCO implementation in Malaysia. A heterogeneous variant of the Susceptible-Exposed-Infected-Recovered (SEIR) model is developed with additional compartments for asymptomatic transmission. Further, a change-point is incorporated to model the before and after disease dynamics, and is inferred based on data. Related statistical analyses for inference are developed in a Bayesian framework and are able to provide quantitative assessments of (1) the impact of the Sri Petaling gathering, and (2) the extent of decreasing transmission during the MCO period. The analysis here also quantitatively demonstrates how quickly transmission rates fall under effective NPI implemention within a short time period.

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Impact of Synthesis Parameters of Multi-Walled Carbon Nanotubes on their Thermoelectric Properties

Materials ◽

10.3390/ma12213567 ◽

2019 ◽

Vol 12 (21) ◽

pp. 3567 ◽

Cited By ~ 3

Author(s):

Bogumiła Kumanek ◽

Grzegorz Stando ◽

Paweł S. Wróbel ◽

Dawid Janas

Keyword(s):

Carbon Nanotubes ◽

Thermoelectric Properties ◽

Synthesis Temperature ◽

Injection Rate ◽

Optimum Synthesis ◽

Synthesis Parameters ◽

Different Temperatures ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

The Impact

Carbon nanotubes have been intensively researched for many years because of a wide array of promising properties that they have. In this paper, we present the impact of synthesis parameters on thermoelectric properties of nanocarbon material. We conducted a number of syntheses of multi-walled carbon nanotubes (MWCNTs) at different temperatures (800 and 900 °C) using various amounts of catalyst (2%, 5.5%, and 9.6%) to facilitate the process. We also tested the influence of injection rate of precursor and the necessity of material purification on thermoelectric properties of MWCNTs. The electrical conductivity, thermal conductivity, and Seebeck coefficient were measurement for all samples. Based on these parameters, the values of Power Factor and Figure of Merit were calculated. The results show that the most important parameter in the context of thermoelectric properties is purity of employed MWCNTs. To obtain appropriate material for this purpose optimum synthesis temperature and appropriate content of the catalyst must be selected. The study also reveals that post-synthetic purification of nanocarbon is essential to produce an attractive material for thermoelectrics.

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Reinforcement Learning From Pixels: Waterflooding Optimization

Volume 11: Petroleum Technology ◽

10.1115/omae2020-18574 ◽

2020 ◽

Author(s):

Ruslan Miftakhov ◽

Igor Efremov ◽

Abdulaziz S. Al-Qasim

Keyword(s):

Reinforcement Learning ◽

Net Present Value ◽

Vertical Section ◽

Water Injection ◽

Petroleum Industry ◽

Injection Pressure ◽

Injection Rate ◽

Simulation Engine ◽

First Case ◽

The Impact

Abstract The application of Artificial Intelligence (AI) methods in the petroleum industry gain traction in recent years. In this paper, Deep Reinforcement Learning (RL) is used to maximize the Net Present Value (NPV) of waterflooding by changing the water injection rate. This research is the first step towards showing that the use of pixel information for reinforcement learning provides many advantages, such as a fundamental understanding of reservoir physics by controlling changes in pressure and saturation without directly accounting for the reservoir petrophysical properties and wells. The optimization routine based on RL by pixel data is tested on the 2D model, which is a vertical section of the SPE 10 model. It has been shown that RL can optimize waterflooding in a 2D compressible reservoir with the 2-phase flow (oil-water). The proposed optimization method is an iterative process. In the first few thousands of updates, NPV remains in the baseline since it takes more time to converge from raw pixel data than to use classical well production/injection rate information. RL optimization resulted in improving the NPV by 15 percent, where the optimum scenario shows less watercut values and more stable production in contrast to baseline optimization. Additionally, we evaluated the impact of selecting the different action set for optimization and examined two cases where water injection well can change injection pressure with a step of 200 psi and 600 psi. The results show that in the second case, RL optimization is exploiting the limitation of the reservoir simulation engine and tries to imitate a cycled injection regime, which results in a 7% higher NPV than the first case.

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Effects of temperature on the composition and diversity of bacterial communities in bamboo soils at different elevations

Biogeosciences ◽

10.5194/bg-14-4879-2017 ◽

2017 ◽

Vol 14 (21) ◽

pp. 4879-4889 ◽

Cited By ~ 3

Author(s):

Yu-Te Lin ◽

Zhongjun Jia ◽

Dongmei Wang ◽

Chih-Yu Chiu

Keyword(s):

Soil Respiration ◽

Bacterial Diversity ◽

Bacterial Communities ◽

Incubation Temperature ◽

Principal Component ◽

Scaling Analysis ◽

Mountain Areas ◽

Bacterial Structure ◽

Incubation Temperatures ◽

The Impact

Abstract. Bamboo is an important resource distributed in mountain areas in Asia. Little is known about the impact of temperature changes on bamboo soil bacterial communities. In this study, responses of bacterial communities collected at 600, 1200, and 1800 m to different incubation temperatures (15, 20, and 35 °C) were examined using barcoded pyrosequencing and soil analyses. Soil respiration was greater at higher elevation and incubation temperature. The bacterial diversity decreased after 112 days of incubation at 35 °C. Before incubation, Acidobacteria and Proteobacteria were the most abundant phyla in all communities. The relative abundance of Acidobacteria generally decreased after 112 days of incubation at the three temperatures. α-Proteobacteria showed a similar trend, while γ-Proteobacteria increased after incubation, except in samples from 1800 m incubated at 35 °C. Non-metric multi-dimensional scaling analysis revealed structural variability under different incubation times and temperatures. Principal component analysis indicated that the bacterial structure in samples incubated at 35 °C correlated with temperature and soil respiration, while structures in samples incubated at 15 and 20 °C correlated with time. These results suggest that a temperature rise could result in increasing soil respiration and soluble carbon and nitrogen consumption as well as differentially influence bacterial diversity and structure at different elevations.

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PSVI-13 Anti-inflammatory effects of polyphenol-rich red osier dogwood extracts in Caco-2 mono- and Caco-2/EA.hy926 co-culture models

Journal of Animal Science ◽

10.1093/jas/skz258.434 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 211-212

Author(s):

Hua Zhang ◽

Yuhuan Chen ◽

Lili Mats ◽

Qianru Hui ◽

Rong Tsao ◽

...

Keyword(s):

Endothelial Cells ◽

Phenolic Compounds ◽

Inflammatory Responses ◽

Cell Model ◽

Circulation System ◽

Systemic Diseases ◽

Potential Health ◽

Tnf Α ◽

Anti Inflammatory ◽

The Impact

Abstract An impaired intestinal barrier function results in aggravating inflammatory response at a systemic scale, eventually leading to rising risk for systemic diseases (e.g., muscle myopathy and vascular disorders). In the present study, the impact of intake polyphenol-rich red osier dogwood extracts (RWE) on the inflammation of endothelial cells was exploited. A strong anti-inflammatory activity of RWE was found to suppress the expression of pro-inflammatory mediators (e.g., IL-8, TNF-α, IL-6, and ICAM) in the inflamed intestinal epithelial cell model. Furthermore, the intestinal transported RWE derived phenolic compounds was shown to protect the endothelial cells against both oxidative and inflammatory damages in a Caco-2/EA.hy926 co-culture cell model. Their protective activities in EA.hy926 was found to be strongly associated with intestinal absorption efficiency. The accumulation of transported rutin and unknown monoglyceride quercetin from RWE were identified across the Caco-2 BBe1 monolayer by HPLC up to 24 h. The highest concentration of transported rutin and monoglyceride quercetin derived from RWE were detected as 2.0 ± 0.22 µg/mL and 0.5 ± 0.08 µg/mL in the basolateral compartment after 12 h and 24 h of incubation, respectively. Profound anti-inflammatory effects of RWE derived polyphenols was observed to suppress pro-inflammatory mediator expression, including IL-8, TNF-α, IL-6, ICAM, VCAM and Cox2, in the TNF-α or oxidized low-density lipoprotein (oxLDL)-induced basolateral EA.hy926 cells (co-culture model). Moreover, we observed a significant inhibitory effect of the transported RWE on oxLDL-induced inflammation after 6 h incubation rather than 24 h, indicating the potential health benefits of RWE is determined by its bioavailability. Results of this study demonstrated that phenolic compounds derived from RWE could be delivered into the circulation system to mitigate inflammatory responses thereby being a promising dietary agent for preventing systemic diseases (e.g., cardiovascular diseases in humans and white stripping/woody meat in broiler chickens).

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