scholarly journals A Proposed Waterpipe Emissions Topography Protocol Reflecting Natural Environment User Behaviour

2019 ◽  
Vol 17 (1) ◽  
pp. 92 ◽  
Author(s):  
Edward C. Hensel ◽  
Samantha Emma Sarles ◽  
Abdulaziz al-Olayan ◽  
A. Gary DiFrancesco ◽  
Shehan Jayasekera ◽  
...  
Keyword(s):  
Flow Rate ◽  
Natural Environment ◽  
Demographic Information ◽  
Flow Conditions ◽  
Session Time ◽  
On Line ◽  
Study Participants ◽  
Monitor Data ◽  
Topography Data ◽  
Screening Survey

Usage of waterpipes is growing in popularity around the world. Limited waterpipe natural environment topography data reduces the ability of the research community to accurately assess emissions and user exposure to toxicants. A portable ergonomic waterpipe monitor was provided to study participants to use every time they smoked their own waterpipe during a one-week monitoring period in conjunction with their own choice shisha tobacco. Users provided demographic information and logged their product use to supplement electronic monitor data. A total of 44 prospective study participants were invited to an intake appointment following an on-line pre-screening survey. Of these, 34 individuals were invited to participate in the study and data for 24 individuals who completed all aspects of the 1-week monitoring protocol is presented. 7493 puffs were observed during 74 waterpipe sessions accumulating over 48 h of waterpipe usage. The 95% CI on mean puff flow rate, duration, volume and interval are presented, yielding grand means of 243 [mL/s], 3.5 [s], 850 [mL], and 28 [s] respectively. The middle 95% of puff flow rates ranged between 62 to 408 [mL/s], durations from 0.8 to 6.8 [s], and puff volumes from 87 to 1762 [mL]. A waterpipe emissions topography protocol consisting of 13 flow conditions is proposed to reflect 93% of the observed range of puff flow rate, puff duration and puff volume with representative inter-puff interval, cumulative session time and aerosol volumes.

Microphotometric Characterization of Fluid Segment Populations Generated in Different Simple Microfluidic Networks

2006 ◽  
Author(s):  
J. M. Ko¨hler ◽  
P. A. Groß
Keyword(s):  
Flow Rate ◽  
Free Fluid ◽  
Flow Conditions ◽  
Carrier Liquid ◽  
Fluid Network ◽  
On Line ◽  
Deformation Stress ◽  
The Stability ◽  
Rate Ratios

The stability of fluid segments is limited by deformation stress and by coalescence events. Both factors are typical for the passage of fluid segments through micro fluidic networks. Therefore, the coalescence behaviour of micro fluid segments in simple net work structures in dependence of flow rate ratios was investigated and characterized by the composition of obtained segment populations. Series of segments of different size and distance were generated either in a double T- or in a triple T-arrangement. PTFE elements were used for the micro fluid network. Nearly pulsation-free fluid actuation was realized by syringe pumps. The flow conditions in the input streams of carrier liquid and injected solutions remained constant during the experiments. Segment sequences become divers by different injection, stacking and coalescence events. The resulting segment sequences were characterized by on-line micro photometry. The populations of obtained micro fluid segments during each experiment were characterized by the distribution of segment size and segment distance or segment periode, respectively. Simulations support the assumption, that the character of segment populations is mainly determined by the flow rate ratios and by the coalescence sensitivity beside the topology of the fluidic network.

Characterization and Validation of the Second-generation wPUM Topography Monitors

2020 ◽  
Author(s):  
Risa J Robinson ◽  
Shehan Jayasekera ◽  
Gary DiFrancesco ◽  
Edward C Hensel
Keyword(s):  
Flow Rate ◽  
Natural Environment ◽  
Health Impact ◽  
Tobacco Product ◽  
Environment Monitoring ◽  
Tobacco Products ◽  
Rate Range ◽  
Flow Rate Range ◽  
Use Behavior ◽  
Topography Data

Abstract Introduction Little is known about the natural use behavior of new and emerging tobacco products due to the limited availability of reliable puff topography monitors suitable for ambulatory deployment. An understanding of use behavior is needed to assess the health impact of emerging tobacco products and inform realistic standardized topography profiles for emissions studies. The purpose of this study is to validate four monitors: the wPUM cigalike, vapepen, hookah, and cigarette monitors. Aims and Methods Each wPUM monitor was characterized and validated for range, accuracy, and resolution for puff flow rate, duration, volume, and interpuff gap in a controlled laboratory environment. Monitor repeatability was assessed for each wPUM monitor using four separate week-long natural environment monitoring studies including cigalike, vapepen, hookah, and cigarette users. Results The valid flow rate range was 10 to 100 mL/s for cigalike and cigarette monitors, 10 to 95 mL/s for vapepen monitors, and 50 to 400 mL/s hookah monitors. Flow rate accuracy was within ±2 mL/s for cigalike, vapepen, and cigarette monitors and ±6 mL/s for the hookah monitor. Durations and interpuff gaps as small as 0.2 s were measured to within ±0.07 s. Monitor calibrations changed by 4.7% (vapepen), 1.5% (cigarette), 0.5% (cigalike), and 0.1% (hookah) after 1 week of natural environment use. Conclusions The wPUM topography monitors were demonstrated to be reliable when deployed in the natural environment for a range of emerging tobacco products. Implications The current study addresses the lack of available techniques to reliably monitor topography in the natural environment, across multiple emerging tobacco products. Natural environment topography data will inform standardized puffing protocols for premarket tobacco product applications. The ability to quantify topography over extended periods of time will lead to a better understanding of use behavior and better-informed regulations to protect public health.

On-Line Monitoring System for Monitoring SO2 in Fumes (1) — Monitoring Subsystem for SO2 Mass Concentration

2011 ◽  
Vol 422 ◽  
pp. 296-299
Author(s):  
Shi Long Wang ◽  
Li Na Wang ◽  
Hong Bo Wang ◽  
Yong Hui Cai
Keyword(s):  
Flow Velocity ◽  
Monitoring System ◽  
Flow Rate ◽  
Mass Concentration ◽  
National Monitoring ◽  
Monitoring Result ◽  
Short Period ◽  
On Line ◽  
Working Principle

In order to achieve the target of controlling SO2 emissions in fumes in a short period of time in China, a SO2 on-line monitoring system (CEMS) has been developed by the authorased on the principle of electrochemistry. This system consists of two subsystems: (1) SO2 mass concentration monitoring and (2) SO2 flow velocity and flow rate monitoring. In the paper, the procedure of system and working principle and method of SO2 mass concentration monitoring subsystem are described in detail (SO2 flow velocity and flow rate monitoring subsystem is described by another paper).Two subsystems work synchronously to monitor and calculate the SO2 emissions, then the on-line monitoring of SO2 emissions is achieved. Through experiment and testing, monitoring result of the system is stable and reliable, which has reached the national monitoring standards and passed the appraisal.

scholarly journals Effect of Fluid Flow on the Corrosion Performance of as-Cast and Heat-Treated Nickel Aluminum Bronze Alloy (UNS C95800) in Saline Solution

2021 ◽  
Vol 2 (1) ◽  
pp. 61-77
Author(s):  
Hamid Reza Jafari ◽  
Ali Davoodi ◽  
Saman Hosseinpour
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Flow Rate ◽  
Solution Temperature ◽  
Aluminum Bronze ◽  
Nickel Aluminum ◽  
Nacl Solution ◽  
Flow Conditions ◽  
Heat Treated ◽  
Nickel Aluminum Bronze

In this work, the corrosion behavior and surface reactivity of as-cast and heat-treated nickel aluminum bronze casting alloy (UNS C95800) in 3.5 wt% NaCl solution is investigated under stagnant and flow conditions. Increasing flow rate conditions are simulated using a rotating disk electrode from 0 to 9000 revolutions per minute (rpm). Optical micrographs confirm the decrease in the phase fraction of corrosion-sensitive β phase in the microstructure of C95800 after annealing, which, in turn, enhances the corrosion resistance of the alloy. Electrochemical studies including open circuit potentiometry, potentiodynamic polarization, and electrochemical impedance spectroscopy are performed to assess the effect of flow rate and heat treatment on the corrosion of samples at 25 and 40 °C in 3.5 wt% NaCl solution. For both as-cast and heat-treated samples, increasing the flow rate (i.e., electrode rotating rate) linearly reduces the corrosion resistance, indicating that the metal dissolution rate is significantly affected by hydrodynamic flow. Increasing the solution temperature negatively impacts the corrosion behavior of the as-cast and heat-treated samples at all flow conditions.

scholarly journals Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Tobias Blanke ◽  
Markus Hagenkamp ◽  
Bernd Döring ◽  
Joachim Göttsche ◽  
Vitali Reger ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Circular Ring ◽  
Flow Conditions ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Pipe Radius

AbstractPrevious studies optimized the dimensions of coaxial heat exchangers using constant mass flow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar flow types. In contrast, in this study, flow conditions in the circular ring are kept constant (a set of fixed Reynolds numbers) during optimization. This approach ensures fixed flow conditions and prevents inappropriately high or low mass flow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic effort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass flow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellström’s borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefficients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy difference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy flux and hydraulic effort. The Reynolds number in the circular ring is instead of the mass flow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54% of the outer pipe radius for laminar flow and 60% for turbulent flow scenarios. Net-exergetic optimization shows a predominant influence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth’s thermal properties and the flow type. Conclusively, coaxial geothermal probes’ design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.

Dune-scale cross-strata across the fluvial-deltaic backwater regime: Preservation potential of an autogenic stratigraphic signature

Geology ◽  
2020 ◽  
Vol 48 (12) ◽  
pp. 1144-1148
Author(s):  
Chenliang Wu ◽  
Jeffrey A. Nittrouer ◽  
Travis Swanson ◽  
Hongbo Ma ◽  
Eric Barefoot ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Mississippi River ◽  
Nonuniform Flow ◽  
Hydrodynamic Conditions ◽  
Flow Conditions ◽  
Bed Topography ◽  
Fundamental Building Block ◽  
Bed Form ◽  
Spatially Varying ◽  
Topography Data

Abstract Dune-scale cross-beds are a fundamental building block of fluvial-deltaic stratigraphy and have been recognized on Earth and other terrestrial planets. The architecture of these stratal elements reflects bed-form dynamics that are dependent on river hydrodynamic conditions, and previous work has documented a multitude of scaling relationships to describe the morphodynamic interactions between dunes and fluid flow. However, these relationships are predicated on normal flow conditions for river systems and thus may be unsuitable for application in fluvial-deltaic settings that are impacted by nonuniform flow. The ways in which dune dimensions vary systematically due to the influence of reach-averaged, nonuniform flow, and how such changes may be encoded in dune cross-strata, have not been investigated. Herein, we explored the influence of backwater flow on dune geometry in a large modern fluvial channel and its implications for interpretation of systematic variability in dune cross-strata in outcrop-scale stratigraphy. This was accomplished by analyzing high-resolution channel-bed topography data for the lowermost 410 km of the Mississippi River, which revealed that dune size increases to a maximum before decreasing toward the river outlet. This spatial variability coincides with enhanced channel-bed aggradation and decreasing dune celerity, which arise due to backwater hydrodynamics. An analytical model of bed-form stratification, identifying spatial variability of cross-set thickness, indicates a prominent downstream decrease over the backwater region. These findings can be used to inform studies of ancient fluvial-deltaic settings, by bolstering assessments of proximity to the marine terminus and associated spatially varying paleohydraulics.

Shattering the Glass Podium: Successes and Setbacks of Women in Collegiate Choral Conducting

2021 ◽  
pp. 875512332110183
Author(s):  
Melissa Baughman
Keyword(s):  
Gender Discrimination ◽  
Online Survey ◽  
Response Rate ◽  
The United States ◽  
Choral Conducting ◽  
Demographic Information ◽  
Choral Conductors ◽  
The Status ◽  
Study Participants ◽  
Experiences Of Women

The purpose of this study was to explore the status and experiences of women in collegiate choral conducting positions. Out of all collegiate choral conductors ( N = 992) at institutions accredited by the National Association of Schools of Music in the United States, 68.65% ( n = 681) were men and 31.35% ( n = 311) were women at the time of this study; I invited the women collegiate choral conductors to serve as study participants. Ninety-six respondents completed an online survey, resulting in a response rate of 30.86%. I collected data through a researcher-designed survey. First, I asked respondents to provide demographic information and respond to Likert-type and open-ended prompts related to three domains: gaining entry into the profession, navigating the profession, and issues surrounding gender. I analyzed data through descriptive statistics and qualitative methods of assigning codes, combining codes into themes, and displaying the data. I addressed general discrepancies in the self-reported attitudes of respondents. Although women reported an overall attitude of satisfaction as choral conductors in their Likert-type responses, many respondents detailed several instances of gender discrimination and other challenges in their open-ended responses. Implications for the music profession, including specific strategies to help empower women in collegiate choral conducting settings, are discussed.

scholarly journals Temperature log simulations in high-enthalpy boreholes

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jia Wang ◽  
Fabian Nitschke ◽  
Maziar Gholami Korzani ◽  
Thomas Kohl
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Fluid Loss ◽  
Flow Conditions ◽  
Flow Rates ◽  
High Enthalpy ◽  
Fluid Losses ◽  
Lateral Heat

Abstract Temperature logs have important applications in the geothermal industry such as the estimation of the static formation temperature (SFT) and the characterization of fluid loss from a borehole. However, the temperature distribution of the wellbore relies on various factors such as wellbore flow conditions, fluid losses, well layout, heat transfer mechanics within the fluid as well as between the wellbore and the surrounding rock formation, etc. In this context, the numerical approach presented in this paper is applied to investigate the influencing parameters/uncertainties in the interpretation of borehole logging data. To this end, synthetic temperature logs representing different well operation conditions were numerically generated using our newly developed wellbore simulator. Our models account for several complex operation scenarios resulting from the requirements of high-enthalpy wells where different flow conditions, such as mud injection with- and without fluid loss and shut-in, occur in the drill string and the annulus. The simulation results reveal that free convective heat transfer plays an important role in the earlier evolution of the shut-in-time temperature; high accuracy SFT estimation is only possible when long-term shut-in measurements are used. Two other simulation scenarios for a well under injection conditions show that applying simple temperature correction methods on the non-shut-in temperature data could lead to large errors for SFT estimation even at very low injection flow rates. Furthermore, the magnitude of the temperature gradient increase depends on the flow rate, the percentage of fluid loss and the lateral heat transfer between the fluid and the rock formation. As indicated by this study, under low fluid losses (< 30%) or relatively higher flow rates (> 20 L/s), the impact of flow rate and the lateral heat transfer on the temperature gradient increase can be ignored. These results provide insights on the key factors influencing the well temperature distribution, which are important for the choice of the drilling data to estimate SFT and the design of the inverse modeling scheme in future studies to determine an accurate SFT profile for the high-enthalpy geothermal environment.

Sensitivity of Effluent Variables in Activated Sludge Process

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
B Vivekanandan ◽  
K Jeyannathann ◽  
A. Seshagiri Rao
Keyword(s):  
Activated Sludge ◽  
Flow Rate ◽  
Oxygen Transfer Rate ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Maximum Flow ◽  
Activated Sludge Process ◽  
Flow Conditions ◽  
Treated Effluent ◽  
Influent Flow

Abstract The quality of a treated effluent changes when there is a sudden variation in the influent flow to the wastewater treatment plant during dry, rain, and storm weather conditions. In this study, various influent flow conditions in an activated sludge process are considered that affect the sensitivity of effluent variables such as chemical oxygen demand (COD), biological oxygen demand (BOD), nitrate nitrogen (SNO), ammonical nitrogen (SNH), and total nitrogen (TN) with respect to varying internal recycle flow rate (Qa), sludge recycle flow rate (Qr), sludge wastage flow rate (Qw) and oxygen transfer rate co-efficient of aerobic tanks (KLa(3,4,5)). The analysis has been carried out based on benchmark simulation model no.1 (BSM 1) plant layout which comprises of two models namely activated sludge model no.1 (ASM 1) and simple one dimensional (Simple 1-D) Takacs model. Based on the present analysis, it is observed that the changes in influent flow rate have larger impact on the effluent variables. This variation can be subdued by introducing additional tanks to smoothen the perturbations or using internal recycle rate from the fifth tank in order to maintain the flow around the optimal influent flow rate. The sludge wastage rate has a greater impact on all effluent variables except nitrogenous variables during maximum flow conditions.

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