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Topic: Residence time

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	The role of topography on catchment-scale water residence time
		The age, or residence time, of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways, and source of water in a single integrated measure.
		While there has been tremendous recent interest in residence time estimation to characterize watersheds, there are relatively few studies that have quantified residence time at the watershed scale, and fewer still that have extended those results beyond single catchments to larger landscape scales.
		Residence times were estimated by simple convolution models that described the transfer of precipitation isotopic composition to the stream network.
	www.agu.org /pubs/crossref/2005/2004WR003657.shtml (435 words)

	Controlled short residence time coal liquefaction process - Patent 4328088
		The total slurry residence time is the time during which the reaction slurry is within the temperature range of this invention, and is based upon the total volume of the slurry, measured under ambient conditions, passing through the reaction assuming that the small volume occupied by gas is negligible.
		The total slurry residence time is continuously controlled by continuously and directly quenching the reaction effluent, i.e., direct intermixing of the reaction effluent with a quenching fluid to substantially immediately reduce the temperature sufficiently to substantially terminate or inhibit polymerization and hydrocracking reactions, e.g., to a temperature below about 425.degree.
		At a 6 minute residence time, the recycle solvent loss was 7.1 weight percent (on a MF coal basis) in the single pass mode, whereas the loss decreased to 0.7 weight percent in the solvent recycle run.
	www.freepatentsonline.com /4328088.html (8204 words)

	Air Trajectory Residence Time Analysis Investigation of Ozone Transport Pathways: 1989-95
		The least probable 25% of scenario residence time hours are in the unshaded, white area of the map.
		The shaded areas in both plots represent grid squares where the residence time-weighted average of all trajectories passing through that square and arriving at the receptor is greater than 50 ppb (approximately the average ozone concentration at both receptor sites).
		As noted with the residence time plots, a broader range of areas are associated with higher ozone levels at Look Rock, and many of these areas were associated with both high and low ozone levels at this site (presumably due to influences of other meteorological factors - such as precipitation, stagnation, cloud cover, etc.).
	capita.wustl.edu /otag/reports/restime/restime.html (2789 words)

	Residence Time Distribution - Wikipedia, the free encyclopedia
		The residence time distribution (RTD) of a chemical reactor or vessel is a description of the time that different fluid elements spend inside the reactor.
		An ideal plug flow reactor has a fixed residence time: Any fluid that enters the reactor at time t will exit the reactor at time t + τ, where τ is the residence time of the reactor.
		The residence time distribution function is therefore a dirac delta function at τ.
	en.wikipedia.org /wiki/Residence_Time_Distribution (224 words)

	Residence Time: Application to Small Boat Basins (Site not responding. Last check: 2007-10-13)
		Using a continuous exchange model, analytical expressions for the transit time distribution function and the age distribution function are derived for a basin having a constant volume.
		The residence time for instantaneous as well as continuous dye injections equals the volume of the basin divided by the rate at which new water is added to the basin.
		Using the tidal prism model it is shown that the normalized residence time for an instantaneous dye injection is a function of three dimensionless parameters.
	www.pubs.asce.org /WWWdisplay.cgi?8301930 (229 words)

	Longitudinal Study: Residence Time (Site not responding. Last check: 2007-10-13)
		A longitudinal analysis of residence time was conducted to see if people who have lived in Charlestown for different amounts of time share similar values and positions on openspace.
		While new residents (0-3 Years) may be the largest supporters of increased openspace acquisition, there appears to be a lack of internal consistency, based on their willingness to back up their positions with increased local taxes.
		While long term residents have lived in Charlestown long enough to witness the course of development in their community, new residents appear to embrace the notion of shutting the door behind them as they enter the community.
	envstudies.brown.edu /thesis/2001/huxol/final/longitudinalres.htm (770 words)

	Fluent NEWS - Spring 2004 - Predicting Residence Time Distribution with FLUENT
		The residence time is the total time spent by the fluid molecules within the reactor.
		Since residence time distributions are routinely, and rather easily measured for process equipment, the RTD predictions allow a rather painless way to validate a complex flow simulation.
		Various potential largescale reactor designs can also be modeled in the same manner, and the residence times predicted to verify that upon scale-up, the large-scale reactor controls the major variables for the process in the same way that the small-scale reactor does.
	www.fluent.com /about/news/newsletters/04v13i1/a23.htm (642 words)

	CDIAC: Atmospheric Heating and Cooling from Fossil-Fuel Combustion
		In contrast, because of the short atmospheric residence time of sulfate aerosols, the GWI of those aerosols is the same as the total or "infinite-time" GWI.
		That value is roughly four times the mass ratio of sulfur to carbon in emissions from fossil-fuel combustion (0.019 for the period 1860 to 1987).
		Consequently, when CO2 forcing is considered for its entire residence time, the positive (warming) influence caused by CO2 substantially exceeds the negative (cooling) influence of the sulfate aerosol, and the net influence of emissions from fossil-fuel combustion is one of warming.
	www.ecd.bnl.gov /steve/CDIAC_94/CDIAC.html (708 words)

	Discharge, Nitrate Load, and Residence Time of Ground Water in the Chesapeake Bay Watershed by Scott W. Phillips, ...
		Quantifying the discharge, nitrate load, and residence time of ground water in the Chesapeake Bay watershed assists in developing an understanding of the movement of nutrients from their sources to streams, and in determining the "lag time" between the implementation of management actions and distinguishable improvement in surface-water quality.
		If nitrate is assumed to move with the ground water, the residence time of water, which is the average time required for ground water to flow from areas of recharge to areas of discharge, can be used to estimate the rates of chemical transport.
		Long-term tritium records were used to calculate residence times for water in seven river basins in the United States and to determine the percentage of annual runoff attributed to "within-year runoff" and the percentage from "long-term reservoirs" (older ground water).
	md.water.usgs.gov /publications/fs-150-99/html/index.htm (3047 words)

	SMIG -- Comment on Various Transport Time Scales (article: September 2002)
		Applications of transport time scales are pervasive in biological, hydrologic, and geochemical studies yet these times scales are not consistently defined and applied with rigor in the literature.
		We compare three transport time scales (flushing time, age, and residence time) commonly used to measure the retention of water or scalar quantities transported with water.
		We then apply the time scale definitions to a shallow 378 ha tidal lake to illustrate how deviations between real water bodies and the idealized examples can result from: (1) non-steady flow; (2) spatial variability in bathymetry, circulation, and transport time scales; and (3) tides that introduce complexities not accounted for in the idealized cases.
	smig.usgs.gov /SMIG/features_0902/timescales.html (328 words)

	Ch 2.4 Residence Time (Site not responding. Last check: 2007-10-13)
		The residence time is effectively the average length of time that an entity, in this case a water molecule, will remain in a reservoir.
		By definition, the residence time is the amount of material in the reservoir, divided by either the inflow or the outflow (they are equal when the reservoir is at equilibrium).
		For our bathtub system here, the residence time is thus 10 liters divided by 1 liter per second, which is equal to 10 seconds.
	www.acad.carleton.edu /curricular/GEOL/DaveSTELLA/modeling/ch2.4.html (274 words)

	Residence Requirements, Registration and Academic Records
		For example, a student registered in Scholastic Residence for three years and taking a Leave of Absence in the fourth will return to Scholastic Residence for his or her fifth year of study and move to Advanced Residence for his or her sixth through twelfth years.
		Note, however, that the choice to reside at a substantial distance from the University does not, in and of itself, qualify a student for Pro Forma status; neither does engagement in the research activity which continues throughout the dissertation stage qualify a student for Pro Forma status.
		During Scholastic Residence, a student who has completed three or fewer years in this status may apply to the dean of students of his or her division or school for a leave of absence of up to four academic quarters.
	catalogs.uchicago.edu /general-residence.html (2110 words)

	Residence Time in Stormwater Detention Basins (Site not responding. Last check: 2007-10-13)
		Residence time has been the traditional indicator of the ability of primary and secondary clarifiers in wastewater treatment plants to remove pollutants from the waste stream.
		The steady-state definition of residence time used in these applications has also been applied to stormwater detention basins in which the flows are unsteady.
		A computer simulator is used to show that theoretical residence in basins receiving unsteady flows can deviate significantly from the steady state values.
	www.pubs.asce.org /WWWdisplay.cgi?8500247 (83 words)

	Tax Planning for Establishing Principal Residence Status
		The court noted that, although use (i.e., time spent in the residence) was probably the most important factor in determining the Guinans’ principal residence, the other factors in the regulations were also considered.
		Both the regulations and the judgment indicate that the most important single factor in determining principal residence status is usage or time in residence during the year.
		For taxpayers such as the Guinans, care should be taken to ensure that the residence with the largest potential gain, or the one most likely to be sold, is used for the majority of the year for at least two years.
	www.nysscpa.org /cpajournal/2005/505/essentials/p52.htm (1475 words)

	Power-law residence time distribution in the hyporheic zone of a 2nd-order mountain stream
		Power-law residence time distribution in the hyporheic zone of a 2nd-order mountain stream
		We measured the hyporheic residence time distribution in a 2nd-order mountain stream at the H. Andrews Experimental Forest, Oregon, and found it to be a power-law over at least 1.5 orders of magnitude in time (1.5 hr to 3.5 d).
		Citation: Haggerty, R. Wondzell, and M. Johnson (2002), Power-law residence time distribution in the hyporheic zone of a 2nd-order mountain stream, Geophys.
	www.agu.org /pubs/crossref/2002.../2002GL014743.shtml (268 words)

	PC-04-02-02 ... Residence Time at Offshore Petroleum Platforms by Characteristic Fish Species
		Knowledge of the residence time of these species would allow a more accurate determination of whether platforms form optimal habitat for depleted species and if they are indeed acting as long-term population reserves.
		As in the pilot study, rockfish will be captured, tagged and monitored using acoustic tags and monitoring equipment to determine their residence time and site fidelity.
		The residence time, site-fidelity, and movement patters for each transmitting fish will be mapped over time in relation to the platforms and any nearby reef sites.
	www.mms.gov /eppd/sciences/esp/profiles/pc/PC-04-02-02.htm (817 words)

	Glossary of System Terminology
		DOUBLING TIME: The time required for a function or variable to increase its value by a factor of two.
		The time required for the exponent to change, or the distance over which it changes, by ~ is called, respectively, the e-folding time or the e-folding distance.
		RESIDENCE TIME: The average time an element of material spends in a reservoir; a characteristic time for a reservoir.
	www.esse.ou.edu /glossary_st.html (2095 words)

	Chemical plant design & operations - Baffled Tank - Residence Time
		I think the best configuration is to have the baffles in a vertical position so that if the tank were empty and being filled it would ensure the residence time because it would force the water to fill up the first chamber then overflow to the next.
		You need a minimum residence time of 10 minutes, so designing a tank with a mean residence time of 15 minutes is a decent first guess- but I doubt that your baffle sections will even approximately give you the residence time distribution of plug flow.
		In my experience, baffle tanks can have very complex residence time distributions, and their effective mean residence times are far shorter than what you might expect.
	www.eng-tips.com /viewthread.cfm?qid=48191 (1482 words)

	How Do I Remove The Conditions On Permanent Residence Based On Marriage?
		You are given conditional resident status on the day you are lawfully admitted to the United States on an immigrant visa or receive adjustment of status.
		You are still married to the same U.S. citizen or lawful permanent resident after two years (your children may be included in your application if they got their conditional resident status at the same time that you did or within 90 days).
		If you and your spouse are unable to apply to remove the conditions on your residence because of divorce or annulment proceedings, you may not apply for a waiver of the requirement to file a joint petition, based on the “good faith” exception.
	www.uscis.gov /graphics/howdoi/remcond.htm (1383 words)

	Merriam-Webster Online
		1 a : the act or fact of dwelling in a place for some time b : the act or fact of living or regularly staying at or in some place for the discharge of a duty or the enjoyment of a benefit
		2a b : the place where a corporation is actually or officially established c : the status of a legal resident
		- in residence : engaged to live and work at a particular place often for a specified time residence at a university>
	www.m-w.com /cgi-bin/thesaurus?residence (204 words)

	The MBARI Chemical Sensor Program - Residence Time
		The value used for the input should be the sum of all inputs to the ocean.
		However, the residence time is often calculated using only one, or more, of the major input processes.
		The residence time can then be calculated using the estimated output, if that is known.
	www.mbari.org /chemsensor/residencetime.html (148 words)

	:: Playa Royale Residence Club ::
		For some people,owning a full time vacation residence in Playa Royale is a very attractive opportunity.
		It’s an excellent stepping stone on your way to retirement that enables you to experience the pleasures of ocean front, resort living without all the burdens of a full time residence.
		Be one of the privileged few to discover the Playa Royale Residence Club and fractional ownership, now one of the newest and fastest growing segments in resort ownership.
	www.playaroyaleresidenceclub.com (238 words)

	Residence Time Effects on Arsenate Adsorption/Desorption Mechanisms on Goethite -- O'Reilly et al. 65 (1): 67 -- Soil ...
		Residence Time Effects on Arsenate Adsorption/Desorption Mechanisms on Goethite -- O'Reilly et al.
		and decrease with increasing equilibration time (Ferguson and Anderson, 1974;
		The samples were reacted with arsenate for 1032 h, and the sorbed geothite samples reacted with phosphate for various amounts of time.
	soil.scijournals.org /cgi/content/full/65/1/67 (5642 words)

	Fluent - Flow Modeling Examples - Residence Time Distribution in CSTR’s
		In CSTRs, the flow patterns are not idealized plug or mixed flow but tend to involve backmixing and channeling of liquid and/or the existence of stagnation zones in the reactor.
		This is done by evaluating the exit age distribution function, E, also referred to as the residence time distribution, or RTD.
		The residence time distribution was determined by modeling the time dependent transport of a neutrally buoyant tracer species.
	www.fluent.com /solutions/examples/x93.htm (183 words)

	Residence Time Distribution and Conversion Calculations for Tanks in Series Model -- from Mathematica Information Center (Site not responding. Last check: 2007-10-13)
		Expression of the Residence Time Distribution for the tanks_in_series model, derived by MacMullin and Weber (1935) (see Chemical Reaction Engineering, O. Levenspiel, 3rd Edition, Wiley,1999, pages 323), are plotted for a number of tanks equal to 1, 2, 3, 5, 10, 20, 50 and 100.
		RTD is also computed form tracer pulse input for a number of tanks equal to 50.
		In such case, the RTD is the outlet tracer concentration versus time curve.
	library.wolfram.com /infocenter/MathSource/5443 (238 words)

	Residence Time analysis Report
		The position of a parcel is logged every 3 hours by a "time stamp", which represents one 3-hour exposure of one parcel to a grid cell’s emissions.
		Similarly, the average tracer concentration measured during the sampling interval is assumed representative of the concentration during every instant of that time interval.
		These normalization factors assure that the number of special case time stamps are equal to approximately 25% of all time stamps.
	capita.wustl.edu /capita/CapitaReports/ResTime/restime.htm (3687 words)

	Residence Time ∓mp; (Site not responding. Last check: 2007-10-13)
		However if cycle time is 20 sec then residence time would be 160 sec.
		This cycle time would be workable with out degradation.
		It would degrade only if there is interruption during production run resulting in increased residence time.
	members.tripod.com /pcbolur/residencetime.html (208 words)

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