bluuebunny/crossref_metadata_2025 huggingface dataset:
A Discussion on Radiographic Sensitivity
Authors: Hastings Carlton H.
Published: July 2009

At the risk of being caught in the crossfire of controversy that has accompanied the subject of radiographic sensitivity since the days of the first radiographic procedure specification, the author will attempt to express his thoughts on this subject in an effort to present a more complete and modern picture of the problem than has been done in the past. Much of the discussion to be presented will not be new but will be presented in the light of recent experiences in the preparation of a general radiographic procedure specification. “The term radiographic sensitivity refers to a combination of contrast and definition which determines the clarity with which variations in dimensions and radiographic opacity of the object being examined are depicted on the exposed film. This quality is, of course, directly related to the ability of the radiograph to reveal defects or other sought for conditions in the object but the latter ability is very difficult to express quantitatively.” It is interesting to note that of several textbooks and manuals on radiography examined, not one presented a word definition and only one of them made specific mention of this term. The one book noted which did present a picture of the significance of the term did so by means of a chart showing the breakdown of factors influencing radiographic sensitivity, a very clear means of explanation. The above definition does not state the meaning of the term nearly as well as it states the factors upon which it depends. This fact is somewhat unfortunate but nonetheless significant. The fact that it is difficult to define directly and the fact that it is incapable of quantitative evaluation leads one to question the advisability of using the term as the keynote to good industrial radiography at the present time. In an attempt to discover the reason for our failure to be able to evaluate radiographic sensitivity quantitatively one must investigate the individual factors involved.
An Investigation of Radiography in the Range from 0.5 to 2.5 Million Volts
Authors: Buechner W. W. , Van de Graaff R. J. , Feshbach H. , Burrill E. A. , Sperduto A. , McIntosh L. R.
Published: July 2009

This article describes an investigation in radiography in the range from 0.5 to 2.5 million volts. The work described began in the summer of 1941 as a contribution to national defense by the Massachusetts Institute of Technology and was later continued and extended under contract with the National Defense Research Committee to meet an urgent radiographic need in the war program, particularly for the Navy. Beginning in 1937, the High Voltage Laboratory at Massachusetts Institute of Technology produced and investigated X-rays of over two-million volts (2 Mev) in connection with nuclear research. Thus, the project could be quickly converted into the exploration of the radiographic possibilities of these penetrating X-rays and into the development of techniques by which they could be applied to the war effort. The expected advantages of the higher voltages were soon confirmed; and, in addition, surprising new advantages were discovered. These results led the National Defense Research Committee to contract with M.I.T. for the development and production of five, compact, 2-Mev X-ray generators. The contract also provided for other work necessarily associated, including the development of new practical radiographic techniques, the servicing of the equipment, and the training of personnel, so that the new generators and their radiation could be used in the field by the Navy with maximum effectiveness. The special war contribution of this radiographic project lay in the fact that, for the first time, it was possible for the Navy to examine the interior of large numbers of the various types of its heavy explosive weapons, including mines, torpedoes, shells, bombs, and rockets. This nondestructive method of examination of these vital weapons made it possible to improve steadily their construction and performance as they were produced and sent out for use against the enemy. This newly introduced range of radiography was also extensively applied to the examination of the interior of many explosive heavy weapons of a particularly hazardous nature captured from the enemy. Moreover, it was possible to examine quickly and with great precision the interior design of optical and other scientific equipment.
Instruments For Rapid Metal Identification
Authors: Webster R. R.
Published: July 2009

The application of instruments in the field of chemical analysis has grown rapidly in the last few years and has been due mainly to recent large-scale advances in electronics and related fields of instrumentation. These have led to improved models of familiar instruments of standard type and to many new instruments heretofore unavailable. Since this equipment serves the dual purpose of increasing the number of chemical determinations that can be made per man-day and decreasing the cost per determination, it is making analytical techniques more widely available as a means of manufacturing and quality control. The extent of this progress is strikingly shown in the techniques for metal analysis. The spectrophotometer has made possible more rapid colorimetric methods for determining composition. The spectrograph for quantitative work, using photographic recording, and more recently the direct reading spectrograph are causing a virtual revolution in analytical methods. X-ray diffraction instruments of both the film and direct-reading type have been found to be very useful in work on metals and the X-ray fluorescence scheme of determining composition has shown considerable possibility as a supplement to spectrographic methods. With a reduction in cost of analysis the use of the analytical laboratory as a production tool has increased. Laboratories specifically designed for the control of manufacturing processes are often built adjacent to the particular process and used for that purpose alone. With the advent of the new high-speed spectrographs this practice is becoming popular.
Rapid Tests for Identifying Alloy Steels
Authors: Kirkham Elbert C.
Published: July 2009

The tests are made by using a chemical kit (9) prepared with reagents and equipment necessary for semi-quantitative spot test analyses of alloy steels. Approximate percentage indications for chromium, cobalt, manganese, nickel, and molybdenum from spot test reactions, along with spark tests for carbon and tungsten, allow the experienced operator to classify alloy steels according to their approximate nominal chemical composition. A classification chart (1) listing representative types of alloy steels helps to properly identify the unknowns. Standard steels (7) of known chemical composition must be spot tested simultaneously with the unknown steels to make the unique combination method reliable. The known standard steels are also used to check the usability of the chemicals in the kit. Rapid sampling must be accomplished in order to obtain best results from the semi-quantitative procedures. Spot test samples from four different steels can be taken by holding glass sampling rods in both hands. Both ends of the rods are used, alternating, so that the same end of the same rod always contacts the same steel to pick up the dissolving acid solutions.
Analysis and Interpretation of Dynamic Records
Authors: Roberts Howard C.
Published: July 2009

This paper attempts to provide a generalized summary of the problems of analysis and interpretation of the data taken in dynamic tests, particularly with regard to the difficulties ordinarily encountered. It does not include detailed descriptions of methods. There is a discussion of the economics of the problem, so far as interpretation and analysis are affected by economic considerations. General methods of processing data by tabulation and by graphical methods are given. The problem of reading and transcribing recorded data is discussed and means of simplifying the analyses are mentioned. There is also a brief description of the applications of computing devices and of mathematical instruments in these analyses. The effect of some limitations in equipment are mentioned.
Introduction
Authors: Speller F. N.
Published: July 2009

A year or two ago the subject of standardizing corrosion testing was brought up for discussion independently in our ferrous and non-ferrous groups. It was decided to appoint a joint committee to obtain papers on various kinds of corrosion testing. We trust that the facts brought out will form a sound basis for further study of the subject by this Society. There is now substantial agreement on the mechanism of corrosion and the influence of various factors, and much is known of the therapeutics of this “disease” of metals, so that we may approach with some confidence the subject of standardization of corrosion testing procedure. Many tests for the physical properties of metals in environments that do not seriously attack the metal have been standardized, but comparatively little has been done towards the establishment of standard tests of the influence of surrounding conditions on various metals. The latter problem is complicated by factors associated both with the metal and its environment, which factors as a rule bear no relation whatever to the physical properties of the metals, but often involve complex surface chemistry phenomena. Unless controlled, corrosion may seriously reduce the useful life of metals either by changes in their structure or section. To start with then, it is important to recognize the fact that the metals most used in construction and others that are less commonly used are essentially unstable forms of matter having more or less tendency to revert to their more stable compounds with release of free energy. It is now generally recognized that when corrosion has started on any specific metal, factors associated with the environment have, as a rule, much more to do with the deterioration of the metal than its composition.
Atmospheric Corrosion Testing
Authors: Rawdon Henry S.
Published: July 2009

The purpose of atmospheric corrosion testing is two-fold: to determine (1) the rate and nature of corrosive attack of a metal by atmospheric agencies and (2) the efficacy of measures used for preventing the attack. Results of such tests should always be correlated with the prevailing atmospheric conditions at the test site. Conclusions supported by tests at one location do not always hold for other locations. The degree and nature of the pollution of the air is a factor which must be very carefully considered. The importance of this factor is often not sufficiently recognized. Specimens having a large area-mass ratio are recommended. This requirement limits the tests in large measure to sheet material. The specimens mounted on rigid permanent racks usually face the south at an angle of approximately 30 deg. to the horizontal. Except in special tests, no specimen should be influenced by another by contact, rain drip or otherwise. Contact of specimens with supports should be minimized by the use of grooved holders of porcelain or other inert material. Quantitative results are based on measurements of change of weight (usually loss of weight, per unit area per unit of time, after cleaning the specimen) or change of strength or other physical property. Loss of ductility is generally considered as being of most significance. Observations on the amount and distribution of surface corrosion can be expressed semiquantitatively. Size of specimens and frequency of inspection vary with the purpose of the test. As large a specimen as practicable is recommended in tests for obtaining engineering corrosion data in which visual inspection is depended upon in the inspection. For change of weight determination, sheet specimens as large as 9 by 12 in. can be used. For change of strength determination conventional test specimens can be used although for some materials it is advisable to machine the tension specimens from the sheet after corrosion. Although no attempt has been made to formulate a recommended practice to be followed in corrosion testing of this kind, a number of factors have been indicated that should be given consideration in any movement along this line.
Salt-Spray Testing
Authors: Dix E. H. , Bowman J. J.
Published: July 2009

Although theoretical studies afford valuable information, simple practical tests are of marked assistance in predicting the resistance of materials to specific corrosive conditions. One of the oldest of these is the salt-spray. The authors believe much of its unpopularity results from uncontrolled variables and the lack of standardized procedures and they present data to show that the test is both useful and reliable when properly administered. The factors which they believe should be controlled are briefly discussed and “standard” conditions for each factor are suggested. However, the paper has been written to stimulate discussion of the test and promote more universal agreement on the testing methods used and is not intended as a “standard practice.”
An Electrical Resistance Method of Determining Corrosion Rates
Authors: Seeber R. R.
Published: July 2009

The use of the increase of the resistance of a specimen to determine its corrosion penetration is not new. Early use of this method was made by Wilson. Later, Hudson made tests with the method to determine its accuracy, and used it extensively in his study of atmospheric corrosion. The following discussion deals with the application of the resistance method of corrosion measurement in a tight iron pipe steam system. The method is basedupon the proved principle that the resistance of a uniform conductor varies inversely as the area of its cross-section. The fact that the products of corrosion have such a high resistance as compared with the resistance of the conductor itself makes it possible to measure the true resistance of the metal itself without first cleaning it. This has a distinct advantage over the gravitational method, which requires that the specimen be thoroughly cleaned without removing the metal itself. In order to measure successfully the amount of corrosion by the change of the resistance of a specimen it is necessary to take account of the following factors: 1. Contact resistance. 2. Type of specimen and holder. 3. Temperature effects.
Lubricating Oils
Authors: Geniesse J. C.
Published: July 2009

The scope of this discussion has been limited to those types of service wherein considerable quantities of lubricants are used, such as in the lubrication of industrial machine bearings, automotive internal combustion engines, and turbines. The primary object of lubrication is to provide between bearing surfaces a film of a type that will permit the conversion and the use of power without large friction losses and without serious harm to the lubricated surfaces. In the case of factory machines, shafting, motors and other housed-in equipment, where the temperature of the bearing does not fluctuate excessively, this is relatively easy since it is merely necessary to provide sufficient inactive fluid of proper viscosity to support the load. In other types of service, the conditions are far more severe. For instance, in some passenger car engines in extreme cases the lubricant must function properly over a temperature range of 350 deg. Fahr. In addition to that, it must not deteriorate too rapidly at higher temperatures nor leave an excess of residue when burned. In the following paragraphs viscosity will be discussed first, since it is the primary factor in practically all cases. It will be followed by a discussion of the limitations that must be imposed on the lubricant in special cases where the conditions of service are severe.
Diesel Fuels
Authors: Rendel T. B.
Published: July 2009

Though the successful development of the Diesel engine depends upon its ability to digest the widest possible range of fuels between kerosine and the heavier residual type of fuel such as bunker C fuel (1, 2, 3), the need for some general specification, particularly for the higher speed engine, is generally admitted. As a result of a multiplicity of conflicting specifications drawn up by various engine manufacturers (4, 5, 6), Committee D-2 of the American Society for Testing Materials first presented in June, 1934, a classification of Diesel fuel oils, dividing them into five grades. This classification has been revised from time to time as a result of suggestions and experimental work carried out by several oil and engine manufacturers' research laboratories, and a further modification has recently been made in respect to the determination of ignition quality. Broadly speaking, in any fuel specifications there are two basic problems to consider: one is the problem of handling the fuel and dispatching that fuel from the refiner's supply tanks to the final fuel injection valve which admits the fuel at the proper time and in the proper form of spray to the combustion chamber; the second problem is to supply a fuel at this valve which will burn completely in the combustion chamber without objectionable exhaust smell or without leaving objectionable deposits which will eventually result in destroying the “tune” or mechanical adjustment of the engine, thus impairing its efficiency. Under the first of these problems we have to consider such properties of the fuel as its flash point, viscosity, pour point, cloud point, and last, but by no means least, its cleanliness (water, sediment, and ash contents). Under the second problem we have to consider its ignition quality, volatility, as expressed by carbon residue or distillation, and sulfur content. The following discussion concerns the various standard and tentative tests used to control these items and the significance of such tests in relation to engine performance.
International Perspectives
Authors: Miwa Masayuki , Kusuda Satoshi , Ikeda Kazushige
Published: July 2009

The number of reports of sudden deterioration in blood pressure with concomitant decrease of urine output among extremely low-birthweight (ELBW) infants whose general condition is stable have increased recently in Japan. This disorder is clearly different from an unstable circulatory status during the acute phase soon after delivery. The disorder usually occurs more than 1 week after birth, when the infant's circulatory status already is stable. Blood pressure in such hypotensive infants cannot be restored with volume expanders or inotropic agents; it only improves with glucocorticoid administration. The efficacy of steroids in preterm infants who develop hypotension soon after birth is widely known, but the time of onset of this paroxysmal hypotension is apparently different. Relative adrenal insufficiency is considered to be the primary cause of this late-onset hypotension, but the pathogenesis has not been elucidated definitively. The disease is diagnosed clinically and by exclusion. When hypotension persists, it may aggravate chronic lung disease (CLD) and cause periventricular leukomalacia (PVL), which emphasizes the importance of early diagnosis and treatment.
Genetic polymorphism in patients with colorectal and with head and neck cancer
Authors: Csejtei András , Tibold Antal , Ember István , Kiss István
Published: July 2009

A colorectalis rákok a második leggyakoribb halálokként szerepelnek a rosszindulatú betegségek között. A fej-nyak táji daganatok halálozása Magyarországon 265%-kal emelkedett az utóbbi 30 évben. Nem lehet eléggé hangsúlyozni e két daganatcsoport közegészségügyi jelentőségét. A colorectalis daganatok esetén a GSTM1, GSTT1 enzimek, valamint a p53 72-es kodonjának, fej-nyak táji tumorok esetén az XRCC1 Arg194Trp és Arg399Gln polimorfizmusainak hatását elemeztük. Intraoperatíve eltávolított daganatos és megfelelően illesztett daganatmentes mintákat válogattunk. A formalinban fixált mintákat deparaffinizáltuk és proteináz-K-emésztésnek vetettük alá. A genotipizálást PCR, illetve a fej-nyak táji tumorok esetén PCR-RFLP módszerrel végeztük. A vizsgált allélek gyakoriságában nem volt különbség a daganatos és a kontrollcsoport között. Túlélés tekintetében szignifikáns különbséget találtunk a GSTM1 és a p53 allélek között Dukes B stádiumú colorectalis daganatok esetén és az XRCC1 194 allélek között III-as stádiumú fej-nyak táji tumorokban. A fenti típusú genetikai különbségek szisztematikus vizsgálata a jövőben hozzájárulhat az egyéni rizikóbecslés és az individualizált kezelések megalapozásához.
Neurobiological and pharmacological aspects of atypical antipsychotic drugs
Authors: Sümegi András
Published: July 2009

Az atípusos (második generációs) antipszichotikumok forradalmi változást hoztak a szkizofrénia és az egyéb pszichotikus zavarok farmakoterápiájában. A jelenleg alkalmazott atípusos szerek fő jellemzője a viszonylag gyenge D2-receptor-gátlás, jóval erősebb szerotonin-5-HT2A-blokkolás mellett. Ezen jellemzők tehetők részben felelőssé a második generációs szerek hatékonyságáért a negatív, a kognitív és az affektív tünetek területén, amely a konvencionális antipszichotikumokra nem vagy csak alig jellemző. A második generációs szerek közül több molekulánál jellemző a D2-receptorról történő gyors disszociáció, amely szintén az atípusos hatásmechanizmus egyik fontos részjelensége lehet. A többféle jeltovábbító rendszer befolyásolása révén az atípusos antipszichotikumok konvencionális társaiknál jóval nagyobb szereppel bírnak a neuronalis plaszticitás megőrzésében. A multiplex neurobiológiai hatásmechanizmus révén a második generációs szerek neuroprotektív mechanizmusaik révén a szkizofrénia kezelésében új minőséget jelentenek.
Our experiences in nephron-sparing surgery in the last nine years
Authors: Könyves Károly , Engert Zoltán , Molnár István , Pánykó Éva , Varga László , Farkas József , Márkus Endre , Hajós György , Scheid Sándor , Rajnai Ildikó
Published: July 2009

A sebészi kezelés az egyetlen bizonyított kuratív eljárás a vesesejtes rák gyógyításában. A szervmegtartó veseműtétek megfelelő indikáció mellett végezve hasonlóan jó recidívamentes és hosszú távú túlélési arányokat biztosítanak, mint a radikális műtétek.
Célkitűzés:
Közleményünkben az elmúlt 9 év során végzett szervmegtartó veseműtétekkel szerzett tapasztalatainkat mutatjuk be, meghatározzuk az egyes műtéti indikációk típusát és arányát, a malignus vesedaganatok szövettani megoszlását, a szövődmények és a daganatmentes túlélési arányokat.
Módszer:
Retrospektív vizsgálattal 1999 és 2008 között, 33, szervmegtartó veseműtéten átesett T1 stádiumú vesedaganatos beteg adatait elemeztük. Az utolsó betegállapot-felmérést 2009 márciusában végeztük. Az átlagos utánkövetési idő 4,64 év volt.
Eredmények:
A betegek 82%-ánál elektív, 3%-ánál relatív és 15%-ánál abszolút indikációval végeztük a műtétet. Az átlagos vesetumorméret 2,86 cm volt. A malignus szövettani elváltozások közül világos sejtes veserák 94%-ban, papilláris veserák 6%-ban igazolódott. Az 1 és 5 éves daganatspecifikus túlélés esélyét 93,8%-nak találtuk. Posztoperatív szövődmény miatt 3 esetben kellett nephrectomiát végeznünk (vérzés, urinoma).
Következtetés:
Megállapításunk szerint a szervmegtartó veseműtét aT1a stádiumú vesedaganatok esetében biztonsággal alkalmazható, kiváló hosszú távú daganatspecifikus túlélést biztosít.
Exposure assessment of 17α-ethinylestradiol in surface waters of the United States and Europe
Authors: Hannah Robert , D'Aco Vincent J. , Anderson Paul D. , Buzby Mary E. , Caldwell Daniel J. , Cunningham Virginia L. , Ericson Jon F. , Johnson Andrew C. , Parke Neil J. , Samuelian John H. , Sumpter John P.
Published: July 2009

An evaluation of measured and predicted concentrations of 17α-ethinylestradiol in surface waters of the United States and Europe was conducted to develop expected long-term exposure concentrations for this compound. Measured environmental concentrations (MECs) in surface waters were identified from the literature. Predicted environmental concentrations (PECs) were generated for European and U.S. watersheds using the GREAT-ER and PhATE™ models, respectively. The majority of MECs are nondetect and generally consistent with model PECs and conservative mass balance calculations. However, the highest MECs are not consistent with concentrations derived from conservative (worst-case) mass balance estimates or model PECs. A review of analytical methods suggests that tandem or high-resolution mass spectrometry methods with extract cleanup result in lower detection limits and lower reported concentrations consistent with model predictions and bounding estimates. Based on model results using PhATE and GREAT-ER, the 90th-percentile low-flow PECs in surface water are approximately 0.2 and 0.3 ng/L for the United States and Europe, respectively. These levels represent conservative estimates of long-term exposure that can be used for risk assessment purposes. Our analysis also indicates that average concentrations are one to two orders of magnitude lower than these 90th-percentile estimates. Higher reported concentrations (e.g., greater than the 99th-percentile PEC of ∼1 ng/L) could result from methodological problems or unusual environmental circumstances; however, such concentrations are not representative of levels generally found in the environment, warrant special scrutiny, and are not appropriate for use in risk assessments of long-term exposures.
PRODUCING AND RECOGNIZING ANALOGICAL RELATIONS
Authors: Lipkens Regina , Hayes Steven C.
Published: July 2009

Analogical reasoning is an important component of intelligent behavior, and a key test of any approach to human language and cognition. Only a limited amount of empirical work has been conducted from a behavior analytic point of view, most of that within Relational Frame Theory (RFT), which views analogy as a matter of deriving relations among relations. The present series of four studies expands previous work by exploring the applicability of this model of analogy to topography‐based rather than merely selection‐based responses and by extending the work into additional relations, including nonsymmetrical ones. In each of the four studies participants pretrained in contextual control over nonarbitrary stimulus relations of sameness and opposition, or of sameness, smaller than, and larger than, learned arbitrary stimulus relations in the presence of these relational cues and derived analogies involving directly trained relations and derived relations of mutual and combinatorial entailment, measured using a variety of productive and selection‐based measures. In Experiment 1 participants successfully recognized analogies among stimulus networks containing same and opposite relations; in Experiment 2 analogy was successfully used to extend derived relations to pairs of novel stimuli; in Experiment 3 the procedure used in Experiment 1 was extended to nonsymmetrical comparative relations; in Experiment 4 the procedure used in Experiment 2 was extended to nonsymmetrical comparative relations. Although not every participant showed the effects predicted, overall the procedures occasioned relational responses consistent with an RFT account that have not yet been demonstrated in a behavior‐analytic laboratory setting, including productive responding on the basis of analogies.
ACQUIRED EQUIVALENCE CHANGES STIMULUS REPRESENTATIONS
Authors: Meeter M. , Shohamy D. , Myers C.E.
Published: July 2009

Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or a change of feature salience. A different way of conceptualizing acquired equivalence is in terms of strategic inference: Confronted with a choice on which it has no evidence, the organism may infer from its history of reinforcement what the best option is, and that inference is observed as acquired equivalence. To test this account, we combined an incremental learning task with an episodic memory test. Drawings of faces were made equivalent through acquired equivalence training, and then paired with words in a list learning paradigm. When participants were asked to recognize specific face‐word pairings, they confused faces more often when they had been made equivalent. This suggests that prior acquired equivalence training does influence how memories are coded. We also tested whether this change in coding reflected acquisition of new associations, as suggested by the associative mediation account, or whether stimuli become more similar through a reweighting of stimulus features, as assumed by some categorization theories. Results supported the associative mediation view. We discuss similarities between this view and exemplar theories of categorization performance.
EXTENSIVE TRAINING IS INSUFFICIENT TO PRODUCE THE WORK‐ETHIC EFFECT IN PIGEONS
Authors: Vasconcelos Marco , Urcuioli Peter J.
Published: July 2009

Zentall and Singer (2007a) hypothesized that our failure to replicate the work‐ethic effect in pigeons (Vasconcelos, Urcuioli, & Lionello‐DeNolf, 2007) was due to insufficient overtraining following acquisition of the high‐ and low‐effort discriminations. We tested this hypothesis using the original work‐ethic procedure (Experiment 1) and one similar to that used with starlings (Experiment 2) by providing at least 60 overtraining sessions. Despite this extensive overtraining, neither experiment revealed a significant preference for stimuli obtained after high effort. Together with other findings, these data support our contention that pigeons do not reliably show a work‐ethic effect.
DELAY, PROBABILITY, AND SOCIAL DISCOUNTING IN A PUBLIC GOODS GAME
Authors: Jones Bryan A. , Rachlin Howard
Published: July 2009

A human social discount function measures the value to a person of a reward to another person at a given social distance. Just as delay discounting is a hyperbolic function of delay, and probability discounting is a hyperbolic function of odds‐against, social discounting is a hyperbolic function of social distance. Experiment 1 obtained individual social, delay, and probability discount functions for a hypothetical $75 reward; participants also indicated how much of an initial $100 endowment they would contribute to a common investment in a public good. Steepness of discounting correlated, across participants, among all three discount dimensions. However, only social and probability discounting were correlated with the public‐good contribution; high public‐good contributors were more altruistic and also less risk averse than low contributors. Experiment 2 obtained social discount functions with hypothetical $75 rewards and delay discount functions with hypothetical $1,000 rewards, as well as public‐good contributions. The results replicated those of Experiment 1; steepness of the two forms of discounting correlated with each other across participants but only social discounting correlated with the public‐good contribution. Most participants in Experiment 2 predicted that the average contribution would be lower than their own contribution.
New Results Improve Fracture-Cleanup Characterization and Damage Mitigation
Authors: Ayoub J. A. , Hutchins R. D. , Van der Bas F. , Cobianco S. , Emiliani C. N. , Glover M. , Marino S. , Nitters G. , Norman D. , Turk G.
Published: July 2009

It is well documented that hydraulic-fracture treatments, although successful, often underperform. Frac-and-pack completions exhibit positive skin values, and traditional hydraulic-fracture completions show discrepancies between the placed propped length and the effective production fracture length. Ineffective fracture cleanup is often cited as a likely cause.

This paper presents some of the results of an investigation of fracture-cleanup mechanisms. This investigation was undertaken under a joint-industry project (JIP) active since the year 2002. The data discussed build on the initial results published in early 2006, which indicated that the polymer concentrates only in the filter cake, and that flow along the fracture encounters significant yield stress when the filter-cake cumulative thickness dominates the width of the fracture.

The new results presented here demonstrate successful strategies that mitigate the effects of excessive filter-cake thickness. Experimental data demonstrate that flow along the fracture would encounter lower yield stress when the breaker is delivered directly to the filter cake as opposed to random distribution. The data also indicate that a smaller breaker amount delivered directly into the filter cake is more effective at reducing the yield-stress effects than a larger breaker amount delivered randomly in the slurry. Alternative breaker materials are explored, and additional data are also presented to estimate the yield-stress effect for fluid flow across the filter cake from the reservoir into the fracture.
Effect of Non-Darcy Flow on Well Productivity of a Hydraulically Fractured Gas-Condensate Well
Authors: Mohan Jitendra , Pope Gary A. , Sharma Mukul M.
Published: July 2009

Hydraulic fracturing is a common way to improve productivity of gas-condensate wells. Previous simulation studies have predicted much larger increases in well productivity than have been actually observed in the field. This paper shows the large impact of non-Darcy flow and condensate accumulation on the productivity of a hydraulically fractured gas-condensate well. Two-level local-grid refinement was used so that very small gridblocks corresponding to actual fracture width could be simulated. The actual fracture width must be used to accurately model non-Darcy flow. An unre-alistically large fracture width in the simulations underestimates the effect of non-Darcy flow in hydraulic fractures. Various other factors governing the productivity improvement such as fracture length, fracture conductivity, well flow rates, and reservoir parameters have been analyzed. Productivity improvements were found to be overestimated by a factor as high as three, if non-Darcy flow was neglected. Results are presented that show the impact of condensate buildup on long-term productivity of wells in both rich and lean gas-condensate reservoirs.
Mechanistic Modeling of Alkaline/Surfactant/Polymer Floods
Authors: Mohammadi Hourshad , Delshad Mojdeh , Pope Gary A.
Published: July 2009

Alkaline/surfactant/polymer (ASP) flooding is of increasing interest and importance because of high oil prices and the need to increase oil production. The benefits of combining alkali with surfactant are well established. The alkali has very important benefits such as lowering interfacial tension (IFT) and reducing adsorption of anionic surfactants that decrease costs and make ASP a very attractive enhanced-oil-recovery method, provided that the consumption is not too large and the alkali can be propagated at the same rate as the synthetic surfactant and polymer. However, the process is complex, so it is important that new candidates for ASP be selected taking into account the numerous chemical reactions that occur in the reservoir. The reaction of acid and alkali to generate soap and its subsequent effect on phase behavior is the most crucial for crude oils containing naphthenic acids. Mechanistic simulation of the ASP flood considering the chemical reactions, alkali consumption, and soap generation and the effect on the phase behavior is the key to success of future field operations. Using numerical models, the process can be designed and optimized to ensure the proper propagation of alkali and effective soap and surfactant concentrations to promote low IFT and a favorable salinity gradient. In this paper, we describe the ASP module of the UTCHEM simulator, which is the University of Texas chemical compositional simulator, with particular attention to phase behavior and the effect of soap on optimum salinity and solubilization ratio. Phase behavior data are presented for sodium carbonate and a blend of surfactants with an acidic crude oil that followed the conventional Winsor phase transition with significant three-phase regions even at low surfactant concentrations. The solubilization data at different oil concentrations were successfully modeled using Hand’s rule. Optimum salinity and solubilization ratio were correlated with soap mole fractions using mixing rules. ASP coreflood results were successfully modeled taking into account the aqueous reactions, alkali/rock interactions, and phase behavior of soap and surfactant. Mechanistic simulations give insights into the propagation of alkali, soap, and surfactant in the core and aid in future coreflood and field-scale ASP designs.
Growth and Phosphorus Uptake of Three Riparian Grass Species
Authors: Kovar John L. , Claassen Norbert
Published: July 2009

Riparian buffers can significantly reduce sediment‐bound P entering surface water, but control of dissolved P inputs is more challenging. Because plant roots remove P from soil solution, it follows that plant uptake can reduce dissolved P losses. We evaluated P uptake of smooth bromegrass (Bromus inermis Leyss.), reed canarygrass (Phalaris arundinacea L.), and switchgrass (Panicum virgatum L.) grown in a flowing nutrient solution culture system with P concentrations of 1 or 100 μmol L−1 Plants were destructively sampled at approximately 0, 26, 40, and 53 days after transplanting (DAT). In a separate, concurrent experiment, we simulated the effect of an inflow of runoff with low or high dissolved P by switching a subset of pots approximately 40 DAT. When grown in 1 μmol L−1 P solution, shoot dry matter (DM) yield increased in the order bromegrass < switchgrass < canarygrass. When grown in 100 μmol L−1 P solution, shoot DM yield increased in the order bromegrass = canarygrass < switchgrass. Shoot P content was correlated with shoot DM yield; however, switchgrass was the only species that had higher P content in plants grown in 100 μmol L−1 P solution than in 1 μmol L−1 P solution. When solution P concentration was abruptly increased or decreased, P uptake was affected more than plant growth. Shoot P concentration of canarygrass increased more than 3.5‐fold when the plants were switched from 1 μmol L−1 P solution to 100 μmol L−1 P solution. Shoot P concentration of switchgrass followed the same trend. The results of this solution‐culture experiment suggest that canarygrass and switchgrass would more effectively deplete dissolved P than would bromegrass.
Soybean Aphid Population Dynamics, Soybean Yield Loss, and Development of Stage‐Specific Economic Injury Levels
Authors: Catangui Michael A. , Beckendorf Eric A. , Riedell Walter E.
Published: July 2009

Stage‐specific economic injury levels (EILs) form the basis of integrated pest management for soybean aphid (Aphis glycines Matsumura) in soybean [Glycine max (L.) Merr.]. Experimental objectives were to develop a procedure for calculating EILs of the soybean aphid specific to the R2 (full bloom), R4 (full pod), and R5 (beginning seed) soybean development stages using the law of the diminishing increment regression model. Soybean aphid population growth over time appeared to follow the symmetrical bell‐shaped and logistic growth curve models. Peak soybean aphid population levels and rates of increase occurred at the R5 development stage and then declined sharply thereafter. Highest peak soybean aphid populations were 21,626 aphids plant−1 for infestations starting at V5, and 6446 aphids plant−1 for infestations starting at R2. Highest maximum aphid‐days plant−1 recorded were 537,217 for V5‐introduced soybean aphids and 148,609 aphid‐days plant−1 for R2‐introduced soybean aphids. On average, the calculated maximum possible yield loss was 75% for soybean aphid infestations starting at the V5 (five node) stage and 48% for soybean aphid infestations starting at the R2 stage. Interrelationships among the current or predicted market value of soybean, cost of soybean aphid control, and the yield potential of the soybean field were considered in the calculations of the stage‐specific EILs. Practical examples for calculating stage‐specific EILs are presented. Economic injury levels were calculated both as soybean aphids plant−1 and soybean aphid‐days plant−1. Use of these stage‐specific EILs may enable growers to manage soybean aphids more accurately.
Zone Tillage Depth Affects Yield and Economics of Corn Silage Production
Authors: Cox William J. , Cherney Jerome H. , Hanchar John H.
Published: July 2009

Increasing numbers of dairies in northeastern United States are classified as confined animal feeding operations (CAFOs). Many dairy farmers in New York (NY) abandoned conventional and adopted zone tillage (ZT) in 4‐yr corn (Zea mays L.) silage‐alfalfa (Medicago sativa L.) rotations on highly erodible land to comply with NY CAFO plans. Farmers now question optimum ZT depth because of increased diesel costs. The objective of this 2‐yr NY study was to determine optimum ZT depth for corn silage in continuous corn and first‐year corn following alfalfa. The ZT depth (with attached Aerway implement), evaluated at 0, 18, and 36 cm, did not affect surface residue (∼34%), plant densities (71,605–73,998 plants ha−1), and dry matter (DM) accumulation at the 12th leaf stage (334–365 g m−2). Significant contrasts were observed between 18 vs. 0 cm for DM yield (19.9 and 18.7 Mg ha−1) and N uptake (236 and 219 kg ha−1, respectively), but not between 18 vs. 36 cm (19.7 Mg ha−1 and 237 kg ha−1).The ZT depth did not affect silage quality. Partial budget analyses indicate that reducing ZT depth from 36 to 18 cm increases profit by ∼$30 ha−1 because of decreased labor ($1.48 ha−1), fuel ($5.88 ha−1), and equipment repair and maintenance costs ($3.01 ha−1) and increased return from higher yield ($21.98 ha−1, offset by $2.57 ha−1 increased harvest cost). We recommend an 18‐cm ZT depth for corn silage in a 4‐yr corn silage‐alfalfa rotation on silt loam soils in northeastern United States.
Field‐Scale Cleanup of Atrazine and Cyanazine Contaminated Soil with a Combined Chemical‐Biological Approach
Authors: Waria M. , Comfort S. D. , Onanong S. , Satapanajaru T. , Boparai H. , Harris C. , Snow D. D. , Cassada D. A.
Published: July 2009

A former agrichemical dealership in western Nebraska was suspected of having contaminated soil. Our objective was to characterize and remediate the contaminated site by a combined chemical‐biological approach. This was accomplished by creating contour maps of the on‐site contamination, placing the top 60 cm of contaminated soil in windrows and mixing with a mechanical high‐speed mixer. Homogenized soil containing both atrazine [6‐chloro‐N‐ethyl‐N′‐isopropyl‐1,3,5‐triazine‐2,4‐diamine] and cyanazine {2‐[[4‐chloro‐6‐(ethylamino)‐1,3,5‐triazin‐2‐yl] amino]‐2‐methylpropanenitrile} was then used in laboratory investigations to determine optimum treatments for pesticide destruction. Iron suspension experiments verified that zerovalent iron (Fe0) plus ferrous sulfate (FeSO4·7H2O) removed more than 90% of both atrazine and cyanazine within 14 d. Liquid chromatography/mass spectrometry (LC/MS) analysis of the atrazine solution after treating with Fe0 and ferrous sulfate identified several degradation products commonly associated with biodegradation (i.e., deethlyatrazine (DEA), deisopropylatrazine (DIA), hydroxyatrazine (HA), and ammelines). Biological treatment evaluated emulsified soybean [Glycine max (L.) Merr.] oil (EOS) as a carbon source to stimulate biodegradation in static soil microcosms. Combining emulsified soybean oil with the chemical amendments resulted in higher destruction efficiencies (80–85%) and reduced the percentage of FeSO4 needed. This chemical‐biological treatment (Fe0 + FeSO4 + EOS, EOS Remediation, Raleigh, NC) was then applied with water to 275 m3 of contaminated soil in the field. Windrows were tightly covered with clear plastic to increase soil temperature and maintain soil water content. Temporal sampling (0–342 d) revealed atrazine and cyanazine concentrations decreased by 79 to 91%. These results provide evidence that a combined chemical‐biological approach can be used for on‐site, field‐scale treatment of pesticide‐contaminated soil.
Estimation of Postfire Nutrient Loss in the Florida Everglades
Authors: Qian Y. , Miao S. L. , Gu B. , Li Y. C.
Published: July 2009

Postfire nutrient release into ecosystem via plant ash is critical to the understanding of fire impacts on the environment. Factors determining a postfire nutrient budget are prefire nutrient content in the combustible biomass, burn temperature, and the amount of combustible biomass. Our objective was to quantitatively describe the relationships between nutrient losses (or concentrations in ash) and burning temperature in laboratory controlled combustion and to further predict nutrient losses in field fire by applying predictive models established based on laboratory data. The percentage losses of total nitrogen (TN), total carbon (TC), and material mass showed a significant linear correlation with a slope close to 1, indicating that TN or TC loss occurred predominantly through volatilization during combustion. Data obtained in laboratory experiments suggest that the losses of TN, TC, as well as the ratio of ash total phosphorus (TP) concentration to leaf TP concentration have strong relationships with burning temperature and these relationships can be quantitatively described by nonlinear equations. The potential use of these nonlinear models relating nutrient loss (or concentration) to temperature in predicting nutrient concentrations in field ash appear to be promising. During a prescribed fire in the northern Everglades, 73.1% of TP was estimated to be retained in ash while 26.9% was lost to the atmosphere, agreeing well with the distribution of TP during previously reported wild fires. The use of predictive models would greatly reduce the cost associated with measuring field ash nutrient concentrations.
Phosphorus Forms in Conventional and Organic Dairy Manure Identified by Solution and Solid State P‐31 NMR Spectroscopy
Authors: He Zhongqi , Honeycutt C. Wayne , Griffin Timothy S. , Cade‐Menun Barbara J. , Pellechia Perry J. , Dou Zhengxia
Published: July 2009

Organic dairy production has increased rapidly in recent years. Organic dairy cows (Bos taurus) generally eat different diets than their conventional counterparts. Although these differences could impact availability, utilization, and cycling of manure nutrients, little such information is available to aid organic dairy farmers in making nutrient and manure management decisions. In this study, we comparatively characterized P in organic and conventional dairy manure using solution and solid state 31P NMR spectroscopic techniques. Phosphorus in both types of dairy manure was extracted with water, Na acetate buffer (100 mmol L−1, pH 5.0) plus 20 mg Na dithionite mL−1, or 0.025 mol L−1 NaOH with 50 mmolL−1 EDTA. Solution NMR analysis revealed that organic dairy manure contained about 10% more inorganic phosphate than conventional dairy manure. Whereas organic dairy manure did contain slightly more phytate P, it contained 30 to 50% less monoester P than conventional dairy manure. Solid state NMR spectroscopy revealed that mono‐, di‐, and trivalent metal P species with different stabilities were present in the two dairy manures. Conventional dairy manure contained relatively higher contents of soluble inorganic P species and stable metal phytate species. In contrast, organic dairy manure contained more Ca and Mg species of P. These results indicate that P transformation rates and quantities should be expected to differ between organic and conventional dairy manures.