Pool Volume Research Articles

Automatic localization of the left ventricular blood pool centroid in short axis cardiac cine MR images.

In this paper, we develop and validate an open source, fully automatic algorithm to localize the left ventricular (LV) blood pool centroid in short axis cardiac cine MR images, enabling follow-on automated LV segmentation algorithms. The algorithm comprises four steps: (i) quantify motion to determine an initial region of interest surrounding the heart, (ii) identify potential 2D objects of interest using an intensity-based segmentation, (iii) assess contraction/expansion, circularity, and proximity to lung tissue to score all objects of interest in terms of their likelihood of constituting part of the LV, and (iv) aggregate the objects into connected groups and construct the final LV blood pool volume and centroid. This algorithm was tested against 1140 datasets from the Kaggle Second Annual Data Science Bowl, as well as 45 datasets from the STACOM 2009 Cardiac MR Left Ventricle Segmentation Challenge. Correct LV localization was confirmed in 97.3% of the datasets. The mean absolute error between the gold standard and localization centroids was 2.8 to 4.7mm, or 12 to 22% of the average endocardial radius. Graphical abstract Fully automated localization of the left ventricular blood pool in short axis cardiac cine MR images.

Hydrologic and water quality performance of regenerative stormwater conveyance installed to stabilize an eroded outfall

Conveying concentrated urban runoff to outfall locations frequently leads to stream bank erosion, channel incision, and the formation of headcuts. Installed in an incised eroded channel, regenerative stormwater conveyance (RSC) is a grade-control and treatment system that uses a series of pools and cascades with an underlying sand bed. As a recently developed practice, RSC performance evaluations are needed to improve the design and guide regulatory accreditation. An eroded channel with a 10% longitudinal slope was stabilized with a five-cell system and monitored for a 14-month period. A small capture volume (6-mm design event) and groundwater intrusion resulted in minimal hydrologic benefit. Hydrologic mitigation was attained only for storms less than 12.7mm. The RSC converted a substantial 50% of inflow to media flow at the second cell; however, the media flow entirely reemerged as surface flow in the saturated downstream pools. Small but statistically significant reductions in event mean concentrations occurred: 17% total suspended sediment (TSS), 17% total phosphorus (TP), and 3% total nitrogen (TN). Water quality improvements occurred primarily between the upstream and second cell, indicating limited processing by the wetter downstream pools. Comparisons between inter-event outflow grab samples and storm event outflow concentrations show nitrogen export during inter-event periods (47% increase in TN concentration). Due to elevated inter-event concentrations, overall mass loading of nitrogen increased. Hydrologic and water quality benefits were garnered only in the first three cells where groundwater intrusion was minimal. Future implementations of RSC are encouraged to account for seasonal high water table elevations that interact with the RSC media and adequately size pool and sand layer capture volumes.

Effects of slurry hold-up on the pool volume of a batch mill

The hold-up of a ball mill in operation is dependent on the dynamic porosity of the bed of grinding balls amongst others. For constant hold-up, the greater the volume of slurry held inside the dynamic bed, the smaller the pool volume. It is to ascertain this experimentally that the dependency between pool and hold-up in a batch mill is investigated here.Using a transparent mill of internal diameter 552mm and length 180mm, the load behaviour of a 10mm ball charge filled at 20% of the volume of the mill and run at 60% critical speed was videoed. Six artificial solutions of viscosity between 0 and 60mPa·s were then prepared for testing. The pool angle was measured for a gradual increase in slurry filling from 0 to 3.After analysis, it was found that Shi’s phenomenological model of slurry hold-up matched well the measurements. Of note is that the predicted pool level was consistently above the actual one by no more than 8° of angle. The measured mean shoulder and toe angles were also observed to deviate by +5.3° and −12.5° respectively from theory. An attempt to explain this was proposed using the experimental evidence at hand.

Examining the effect of geomorphic characteristics on pool temperatures for native fish habitat management in mountainous stream networks

AbstractStream temperature is a critical habitat parameter for cold‐water fish, many species of which now exist in geographically fragmented populations within the western United States. To assist managers in identifying thermally suitable fish habitat, we used data from 31 pools on streams of the White River National Forest in Colorado, USA to create multiple regression models to predict summer pool temperature metrics related to lethal and sublethal thermal tolerances of fish. We modeled the 7‐day mean of daily maximum pool temperature for the warmest 7 days and the mean temperature of the warmest month, using air temperature and several geomorphic parameters. The strongest predictor variables of these temperature metrics were drainage area, discharge, and residual pool volume. Most previous studies found air temperature to be the strongest predictor variable for pool temperature, but for the mountain streams in this study, variables related to stream flow volume and stream morphology had better predictive power. The models, created from and tested against field data, were able to explain 66% and 51% of the variability in monthly mean and 7‐day mean pool temperatures, respectively, and had prediction errors of less than 2°C. The reach‐scale approach developed here, which includes geomorphically relevant predictors of pool temperature, should be applicable to other mountainous river networks. Copyright © 2016 John Wiley & Sons, Ltd.

Experimental investigations of heat transfer from an internally finned two phase closed thermosyphon

This paper reports the results of an experimental investigation of heat transfer from an internally finned thermosyphon charged with either water or acetone. Six constant area fins with a rectangular cross section are placed internally along the length at the condenser section. The ratio of initial liquid pool volume to the evaporator volume, known as the filling ratio in a thermosyphon system, has been varied in this study. Experiments are carried out for filling ratios of 20, 50, and 80% for two working fluids (i) water and (ii) acetone. Results show that a fill ratio of 50% gives better heat transfer performance. Providing internal fins at the condenser produces additional condensation which improves the thermal performance of the thermosyphon by 17% in terms of the temperature reduction at the source and sink and 35.48% in terms of reduction in thermal resistance at lower heat inputs. The thermosyphon is tested between power levels of 50 and 275W.

Interacciones parasito hospedero en peces del intermareal rocoso de la zona centro y centro sur de Chile: comparacion de la diversidad, conectancia y densidad de vinculos

Despite the fact interactions between parasites and hosts are constant and obligatory for parasites; the spatial variations of these relationships are poorly understood. In this study we aim to quantify and compare the host-parasite interactions in intertidal fish from two sampling zones: the central (33°S) and central-south (36°S) of Chile. A total of 2,081 fish were collected from 56 rocky pools. Biomass and abundance of fish between the two sampling zones, central (ZC) and central-south (ZCS), was compared. Common fish species between both zones were considered for parasitological analysis and comparisons between zones. The prevalence, abundance, richness and diversity of parasites were also compared between zones. The abundance and biomass of fish, as well as all the parasitological parameters were standardized by the rocky pool volume (m 3 ). Beside the fact that fish abundance and biomass of fish and the community parameters were different between ZC and ZCS for some fish species, after standardization to pool volumes (m 3 ), no difference was found in them. There was medium-low parasitic species similarity (<55%) between sampling zones, however, the parameters of host-parasite interaction, such as connectedness and link density, were not significantly different. This may be partly due to the similarity of species richness of fish maintaining their “parasite species load”, regardless of parasite species. Parasite communities have been determined as unsaturated with species, meaning that the host has niches which may be used by parasite species available in a certain host locality.

Investigation of molten pool behavior and weld bead formation in VP-GTAW by numerical modelling

A three dimensional model is proposed to characterize the transport phenomena in molten pool and weld bead formation in high speed VP-GTAW. The temperature and velocity distribution, deformation of molten pool free surface and weld bead profile are systematically discussed. The molten pool temperature exhibits a periodically fluctuations (20–40K), and the molten pool shape and velocity remain minor oscillation in the DCEN and DCEP phases. The velocity increases dramatically to 1.012m/s at the initial stage (0–0.01s), then the velocity remains stable as the further development of molten pool volume (0.01–0.4s). Two forms of flow patterns driven by surface tension and electromagnetic force are dominated in the molten pool. The formation mechanisms of weld bead defects (undercut, humping) are analyzed. The simulated weld bead profiles are agree well with the experimental weld appearance. This numerical study may provide a good foundation for optimizing the VP-GTAW process to achieve quality welds.

Technological Aspects Regarding Manual Metal Arc Welding Using Pulsed Current for Fillet Joints Applications

The idea of using electrical pulse current at manual arc welding with coated electrode starts from the observation of frequency influence, unchanging in manual TIG welding with filler materials, on weld pool volume, by partial solidification of the weld pool in base time of the pulse current, thus being able to control its volume.This paper presents for the first time this new challenge of inverter modern sources: manual metal arc welding using pulsed current.Experimental research findings highlight the technological aspects when using pulsed current in manual metal arc welding, using STEL welding equipment that has this option. The application - concerns the establishment the lack of fusion welded joints in fillet positions. It highlights the beneficial effect of pulsed current, in particular by the joint penetration.Experiments have pursued highlighting of welding pulsed current and frequency of the pulses by the appearance of the joint and the influence by weld geometry for lack of fusion fillet joint. Also, the influence of frequency pulsed current by arc stability, sprays, etc. compared with standard welding was observed.

Sources and interpretation of channel complexity in forested subalpine streams of the Southern Rocky Mountains

AbstractWe evaluate correlations between stream geomorphic complexity and characteristics of the adjacent riparian forest, valley geometry, and land use history in forested subalpine streams of the Colorado Front Range. Measures of geomorphic complexity focus on cross‐sectional, planform, and instream wood piece and logjam variables. We categorize adjacent riparian forests as old‐growth unmanaged forest (OU), younger unmanaged forest (YU), and younger managed forest (YM), and valley geometry as laterally confined, partly confined, or unconfined. Significant differences in geomorphic stream complexity between OU, YU, and YM result primarily from differences in wood pieces and logjams, and these differences correlate strongly with pool volume and organic matter storage. Significant differences in planform and cross‐sectional complexity correlate more strongly with valley geometry, but do not explain as much of the observed variability in complexity between streams as do the wood variables. Unconfined OU streams have the largest wood loads and the greatest complexity, whereas legacy effects of logging, tie‐drives, and channel simplification create lower complexity in YM streams, even relative to YU streams flowing through similarly aged forest. We find that management history of riparian forests exerts the strongest control on reduced functional stream channel complexity, regardless of riparian forest stand age.

Wood and sediment storage and dynamics in river corridors

AbstractLarge wood along rivers influences entrainment, transport, and storage of mineral sediment and particulate organic matter. We review how wood alters sediment dynamics and explore patterns among volumes of in‐stream wood, sediment storage, and residual pools for dispersed pieces of wood, logjams, and beaver dams. We hypothesized that: volume of sediment per unit area of channel stored in association with wood is inversely proportional to drainage area; the form of sediment storage changes downstream; sediment storage correlates with wood load; the residual volume of pools created in association with wood correlates inversely with drainage area; and volume of sediment stored behind beaver dams correlates with pond area. Lack of data from larger drainage areas limits tests of these hypotheses, but the analyses suggest that sediment volume correlates positively with drainage area and wood volume. The form of sediment storage in relation to wood appears to change downstream, with wedges of sediment upstream from jammed steps most prevalent in small, steep channels and more dispersed sediment storage in lower gradient channels. Pool volume correlates positively with wood volume and negatively with channel gradient. Sediment volume correlates well with beaver pond area.More abundant in‐stream wood and beaver populations present historically equated to greater sediment storage within river corridors and greater residual pool volume. One implication of these changes is that protecting and re‐introducing wood and beavers can be used to restore rivers. This review of the existing literature on wood and sediment dynamics highlights the lack of studies on larger rivers. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Determinants of protein elution rates from preparative ion-exchange adsorbents

The rate processes involved in elution in preparative chromatography can affect both peak resolution and hence selectivity as well as practical factors such as facility fit. These processes depend on the physical structure of the adsorbent particles, the amount of bound solute, the solution conditions for operation or some combination of these factors. Ion-exchange adsorbents modified with covalently attached or grafted polymer layers have become widely used in preparative chromatography. Their often easily accessible microstructures offer substantial binding capacities for biomolecules, but elution has sometimes been observed to be undesirably slow. In order to determine which physicochemical phenomena control elution behavior, commercially available cellulosic, dextran-grafted and unmodified agarose materials were characterized here by their elution profiles at various conditions, including different degrees of loading. Elution data were analyzed under the assumption of purely diffusion-limited control, including the role of pore structure properties such as porosity and tortuosity. In general, effective elution rates decreased with the reduction of accessible pore volume, but differences among different proteins indicated the roles of additional factors. Additional measurements and analysis, including the use of confocal laser scanning microscopy to observe elution within single chromatographic particles, indicated the importance of protein association within the particle during elution. The use of protein stabilizing agents was explored in systems presenting atypical elution behavior, and l-arginine and disaccharide excipients were shown to alleviate the effects for one protein, lysozyme, in the presence of sodium chloride. Incorporation of these excipients into eluent buffer gave rise to faster elution and significantly lower pool volumes in elution from polymer-modified adsorbents.

Effect of keyhole geometry and dynamics in zero-gap laser welding of zinc-coated steel sheets

Both zinc-coated and uncoated DP 590 steel sheets were used for laser welding experiment with a 2kW multi-mode fiber laser under the same experimental conditions. Using systematically obtained keyhole data, how the keyhole dynamically responds to an incident laser beam was studied by defining several key factors, such as keyhole expansion factor, keyhole motion range factor, average aperture diameters, mass loss fraction and melt pool volume size. The relative configuration of the keyhole and the laser beam was found to be the most influential factor for obtaining good welds, and when the beam was located away from the front keyhole wall a good weld was obtained. When the beam irradiates on the front keyhole wall, the zinc evaporation region between the two sheets can be directly heated by the beam, and the zinc vapor pressure can become extremely large, and therefore the melt pool is severely disturbed. The keyhole bottom aperture diameter and the keyhole expansion factor for the bottom aperture were both largely proportional to the mass loss for both zinc-coated and uncoated steels. Zero-gap laser welding of zinc-coated steels can be indeed successful and a theoretical basis is presented.

The rapid identification of elution conditions for therapeutic antibodies from cation-exchange chromatography resins using high-throughput screening

Cation-exchange chromatography is widely used in the purification of therapeutic antibodies, wherein parameters such as elution pH and counterion concentration require optimization for individual antibodies across different chromatography resins. With a growing number of antibodies in clinical trials and the pressure to expedite process development, we developed and automated a high-throughput batch-binding screen to more efficiently optimize elution conditions for cation-exchange chromatography resins. The screen maps the binding behavior of antibodies and impurities as a function of pH and counterion concentration in terms of a partition coefficient (Kp). Using this approach, the binding behavior of a library of antibodies was assessed on Poros 50HS and SP Sepharose Fast Flow resins. The diversity in binding behavior between antibodies and across resins translated to the requirement of a variable counterion concentration to elute each antibody. This requirement can be met through the use of a gradient elution. However, a gradient of increasing counterion concentration spans the transition from binding to non-binding for impurities as well as the antibody, resulting in the elution of impurities within the antibody elution peak. Step elution conditions that selectively elute the antibody while retaining impurities on the resin can now be rapidly identified using our high-throughput approach. We demonstrate that by correlating antibody Kp to elution pool volume and yield on packed-bed columns and through the calculation of a separation factor, we can efficiently optimize step elution conditions that maximize impurity clearance and yield for each antibody.

Petroleum refinery greenhouse gas emission variations related to higher ethanol blends at different gasoline octane rating and pool volume levels

AbstractRefinery GHG emissions were predicted for 10% and 30% ethanol blends at refinery blendstock octanes between 77 and 89 AKI at any gasoline pool energy content between parity and constant gasoline pool volume. Linear programming analyzed how separate E30 blending scenarios of 2017 PADD 2‐based refineries affect greenhouse gas (GHG) emissions relative to status quo gasoline (i.e., E10, 87 AKI and 93 AKI premium). The compliance synergy of higher ethanol blends illustrated here is pertinent to national policy goals and multiple environmental objectives. Study results have implications for CAFE Standards, US EPA Tier 3 fuel standards, and Clean Air Act regulations of stationary source CO2 emissions from refinery operations. Results varied by amounts and types of crude oil processed, refinery operations, refinery gasoline blendstock produced (and fuel ethanol blended), and produced refinery product composition and properties. Significant differences exist in total refinery GHG emissions (including emissions from purchased electricity and hydrogen) with the largest differences from coke burn in the fluidized catalytic cracker and refinery fuel gas combustion principally related to reformer operations. The concept of refinery GHG emissions intensity was introduced to differentiate between differences in refinery throughput (an extensive factor) and severity of refinery operations (intensive factors). Refinery GHG emissions decline 12% to 27% from a 2017 base case for the various 30% ethanol cases, highlighting a significant gap in current life cycle analysis (LCA) and supporting incorporation of this improved approach into LCA related to higher ethanol blends. This methodology can be adapted to other PADDs and/or for the USA. ©2015 The Authors. Biofuels, Bioproducts, Biorefining published by Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Instream Flows: New Tools to Quantify Water Quality Conditions for Returning Adult Chinook Salmon

AbstractThis paper examines the effect of implementing a water transaction program to address potential water quality limitations for returning adult fall-run Chinook salmon in a stream system where the agriculture is the dominant land and water use. Water transactions are becoming an increasingly used approach to provide instream flows during periods when there are competing water uses. Water transactions are often used to achieve ecological objectives, but their water quality or biological effects are rarely quantified. The effects of a water transaction implemented in the Shasta River were evaluated by using a spreadsheet model to quantify changes in dissolved oxygen conditions as they relate to discharge, pool volumes, holding habitat capacity, and potential dissolved oxygen demand by holding fish. The results indicate that water transactions may mitigate potential water quality impairments by decreasing the residence time in holding habitat, and are particularly effective during periods when flows ar...

BWR MARK I pressure suppression pool mixing and stratification analysis using GOTHIC lumped parameter modeling methodology

As a part of the GOTHIC (GOTHIC incorporates technology developed for the electric power industry under the sponsorship of EPRI.) Fukushima Technical Evaluation project (EPRI, 2014a, b, 2015), GOTHIC (EPRI, 2014c) has been benchmarked against test data for pool stratification (EPRI, 2014a, b, Ozdemir and George, 2013). These tests confirmed GOTHIC’s ability to simulate pool mixing and stratification under a variety of anticipated suppression pool operating conditions. The multidimensional modeling requires long simulation times for events that may occur over a period of hours or days. For these scenarios a lumped model of the pressure suppression chamber is desirable to maintain reasonable simulation times. However, a lumped model for the pool is not able to predict the effects of pool stratification that can influence the overall containment response. The main objective of this work is on the development of a correlation that can be used to estimate pool mixing and stratification effects in a lumped modeling approach. A simplified lumped GOTHIC model that includes a two zone model for the suppression pool with controlled circulation between the upper and lower zones was constructed. A pump and associated flow connections are included to provide mixing between the upper and lower pool volumes. Using numerically generated data from a multidimensional GOTHIC model for the suppression pool, a correlation was developed for the mixing rate between the upper and lower pool volumes in a two-zone, lumped model. The mixing rate depends on the pool subcooling, the steam injection rate and the injection depth.

Fragmentation of an Intermittent Stream During Seasonal Drought: Intra‐annual and Interannual Patterns and Biological Consequences

AbstractIntermittent streams lose surface flow during some portion of the year and can be important breeding and rearing habitats for stream biota. However, habitat contraction and deteriorating water quality across the summer can result in harsh conditions and mortality. We explored patterns of drying in a small intermittent stream across the summer in Mediterranean‐climate California, including across 4 years that differed in antecedent precipitation. Wet–dry mapping revealed earlier stream fragmentation following dry winters and that entire sections of the stream varied in their propensity to dry suggesting an important influence of geomorphology on drying. Within two ‘slow‐drying’ reaches, initial riffle volumes were higher following wetter winters, but the rate of riffle drying was higher following wet years, presumably because higher initial volumes resulted in greater drying capacity. Initial pool volumes were similar across years, but the rate of pool drying was faster following dry versus wet winters (pool half‐life ranged from 9.7 weeks in the driest year to 26.3 weeks in the wettest year). Stream temperature differed among years, but differences were slight, and temperatures rarely exceeded optimal conditions for trout growth. We observed limited movement of trout during drier years and found that movement was negatively associated with pool depth, riffle length and date, and positively associated with riffle volume. Overall, we found that antecedent rainfall influenced variability in pool drying more than riffle drying, that entire sections of the creek varied in their propensity to dry and that biological fragmentation preceded physical fragmentation by 3 to 7 weeks. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Influence of modes of metal transfer on grain structure and direction of grain growth in low nickel austenitic stainless steel weld metals

The present study elaborately discussed the effect of different modes of metal transfer (i.e., short circuit mode, spray mode and pulse mode) on grain structure and direction of grain growth in low nickel austenitic stainless steel weld metals. Electron backscattered diffraction (EBSD) analysis was used to study the grain growth direction and grain structure in weld metals. The changes in grain structure and grain growth direction were found to be essentially varied with the weld pool shape and acting forces induced by modes of metal transfer at a constant welding speed. Short circuit mode of metal transfer owing to higher Marangoni force (Ma) and low electromagnetic force (Rm) promotes the lower weld pool volume (Γ) and higher weld pool maximum radius (rm). Short circuit mode also shows curved and tapered columnar grain structures and the grain growth preferentially occurred in <001> direction. In contrast, spray mode of metal transfer increases the Γ and reduces the rm values due to very high Rm and typically reveals straight and broad columnar grain structures with preferential growth direction in <111>. In the pulse mode of metal transfer relatively high Ma and Rm simultaneously increase the weld pool width and the primary penetration which might encourage relatively complex grain growth directions in the weld pool and cause a shift of major intensity from <001> to <111> direction. It can also be concluded that the fusion zone grain structure and direction of grain growth are solely dependent on modes of metal transfer and remain constant for a particular mode of metal transfer irrespective of filler wire used.

Instream wood loads in montane forest streams of the Colorado Front Range, USA

Although several studies examine instream wood loads and associated geomorphic effects in streams of subalpine forests in the U.S. Southern Rocky Mountains, little is known of instream wood loads in lower elevation, montane forests of the region. We compare instream wood loads and geomorphic effects between streams draining montane forest stands of differing age (old growth versus younger) and disturbance history (healthy versus infested by mountain pine beetles). We examined forest stand characteristics, instream wood load, channel geometry, pool volume, and sediment storage in 33 pool–riffle or plane-bed stream reaches with objectives of determining whether (i) instream wood and geomorphic effects differed significantly among old-growth, younger, healthy, and beetle-infested forest stands and (ii) wood loads correlated with valley and channel characteristics. Wood loads were standardized to drainage area, stream gradient, reach length, bankfull width, and floodplain area. Streams flowing through old-growth forests had significantly larger wood loads and logjam volumes (pairwise t-tests), as well as logjam frequencies (Kruskal–Wallis test), residual pool volume, and fine sediment storage around wood than streams flowing through younger forests. Wood loads in streams draining beetle-infested forest did not differ significantly from those in healthy forest stands, but best subset regression models indicated that elevation, stand age, and beetle infestation were the best predictors of wood loads in channels and on floodplains, suggesting that beetle infestation is affecting instream wood characteristics. Wood loads are larger than values from subalpine streams in the same region and jams are larger and more closely spaced. We interpret these differences to reflect greater wood piece mobility in subalpine zone streams. Stand age appears to exert the dominant influence on instream wood characteristics within pool–riffle streams in the study area rather than beetle infestation, although this may reflect the relatively recent nature (<10years) of the infestation.

Real-time monitoring of hemodynamic changes in tumor vessels during photoimmunotherapy using optical coherence tomography.

Photoimmunotherapy (PIT) is a cell-specific cancer therapy based on an armed antibody conjugate that induces rapid and highly selective cancer cell necrosis after exposure to near-infrared (NIR) light. The PIT treatment also induces the superenhanced permeability and retention effect, which allows high concentrations of nanoparticles to accumulate in the tumor bed. In our pilot studies, optical coherence tomography (OCT) reveals dramatic hemodynamic changes during PIT. We developed and applied speckle variance analysis, Doppler flow measurement, bulk motion removal, and automatic region of interest selection to quantify vessel diameter and blood velocity within tumors in vivo. OCT imaging reveals that blood velocity in peripheral tumor vessels quickly drops below the detection limit while the vessel lumen remains open (4 vessels from 3 animals). On the other hand, control tumor vessels (receive NIR illumination but no PIT drug) do not show the sustained blood velocity drop (5 vessels from 3 animals). Ultraslow blood velocity could result in a long drug circulation time in tumor. Increase of the blood pool volume within the central tumor (shown in histology) may be the leading cause of the periphery blood velocity drop and could also increase the drug pool volume in tumor vessels.