Добірка наукової літератури з теми "Cumulative Plots"

Thirteen termite mounds and 13 similar-sized control plots were surveyed in central Zimbabwe in order to study large mammalian browsing and vegetation characteristics. The mounds supported almost twice as many tree species as the control plots and the woody vegetation was denser on mounds compared with the woodland plots. Species of woody plants were recorded along with the percentage of branches browsed (cumulative browsing score) by black rhino, Diceros bicornis, elephant, Loxodonta africana and other browsers combined. In addition we measured how the cumulative browsing score on three woody plant species, Acacia nilotica, Colophospermum mopane and Dichrostachys cinerea, which were common both on and off mounds, was related to the distance from mound centre. Both black rhino and elephant cumulative browsing scores were significantly higher on the mound plants compared with the woodland plots. Cumulative browsing score was negatively related to distance from the mound centre for Dichrostachys cinerea, Colophospermum mopane and Acacia nilotica. We propose that termite mound construction in miombo woodland contributes to sustaining populations of megaherbivores and perhaps some woody species in these areas.

To restore the productivity of a deteriorated sward due to weed invasion, renovation (re-sowing) is necessary. However, the renovation method used can affect the sward’s greenhouse gas (GHG) emissions and herbage yield. This study compared the effects of renovation using full inversion tillage (F), shallow tillage (S), or a tine drill (T) on the GHG emissions and herbage yield of a grassland in Nasu, Japan. Two adjacent grasslands were renovated in September 2015 (year 1) and 2016 (year 2). In each year, F, S, and T plots (5 m × 20 m each) were arranged in a randomized complete block design with four replications and then orchardgrass (Dactylis glomerata L.) was seeded. All plots received 40 kg-N ha−1 for renovation and 190 kg-N ha−1 y−1 the following year. Carbon balance (i.e., the difference between C input through crop residue and C output through heterotrophic respiration), methane (CH4) and nitrous oxide (N2O) emissions, and herbage yield were measured over a period of 411 or 412 days. Cumulative N2O emissions were significantly smaller from F and S plots than from T plots, however, there was no significant difference in the sum of GHG emissions (i.e., C balance plus cumulative CH4 and N2O emissions) among F, S, and T plots. The cumulative total herbage yields of the F, S, and T plots did not differ significantly from each other. Consequently, the GHG intensity—i.e., the sum of GHG emissions per cumulative total herbage yield—was not significantly different among the F, S, and T plots.

During the late summers of 1991, 1992, and 1993, the occurrence and severity of foliar symptoms on ozone-sensitive eastern hardwood species (black cherry (Prunusserotina Ehrh.), yellow-poplar (Liriodendrontulipifera L.), and white ash (Fraxinusamericana L.)) in the Shenandoah National Park, Va., and relationships between the observed symptoms and cumulative ambient ozone exposures were determined. Three plots containing 30 trees of each species were established adjacent to air quality monitoring stations located at three different elevations. The symptom response of black cherry was most clearly correlated with ozone exposure. The best-fit regression model describing the relationship between cumulative ozone exposures and foliar injury was quadratic (y = a + bx2 + e); the most significant relationships were foliar injury versus the cumulative ozone concentrations of ≥60 ppb and the cumulative ozone concentrations weighted by a sigmoidal function. These observations suggest that higher ozone exposures are more important to foliar symptom development, but cumulatively all exposures contribute to the effect. In 1992, the progression of symptom development on 10 black cherry trees at each site was observed and related to cumulative ozone; there was an exponential increase of foliar injury with cumulative ozone throughout the summer. In 1993, eight subplots of five black cherry saplings were established, and ozone-induced symptom incidence and severity was compared with those on overstory trees at associated trend plots. There was no significant difference in symptom expression between overstory and sapling trees; therefore, Park Service personnel can use the more accessible saplings instead of overstory trees to monitor ozone symptoms in the Park.

Runoff, sediment yield and infiltration process of shrub plots were studied under rainfall intensities of 45, 87 and 127 mm/h with 20° slope gradient using simulated rainfall experiment. The results showed that cumulative runoff and cumulative sediment yield of shrub plot had an obvious positive correlation with rainfall time. Under rainfall intensity of 45 mm/h, runoff and sediment yield of shrub plot kept a constant level. Under rainfall intensity of 87 mm/h, runoff kept a fluctuant increase, whereas sediment yield basically kept steady. Under rainfall intensity of 127 mm/h, runoff and sediment yield of shrub plot increased evidently due to the formation of erosion pits. Infiltration rate of shrub plot had a negative relation with runoff as well as sediment yield.

AbstractTraps baited with either ethyl (E,Z)-2,4-decadienoate (pear ester) or (E,E)- 8,10- dodecadien-1-ol (codlemone) (Pherocon® CM-DA™ and Megalure CM™ lures, respectively) were used to develop action thresholds for codling moth (Cydia pomonella (L.)) in apple (Malus domestica Borkh.; Rosaceae) orchards treated with sex pheromones for control of this pest. Studies were conducted in 102 orchards treated with 500–1000 ISOMATE®-C PLUS dispensers per hectare during 2000–2002. Pairs of traps were placed within two 1.0-ha plots within each orchard. Fruit injury was assessed at mid-season and prior to harvest in each plot. The numbers of female and total moths caught in pear ester-baited traps and male moths caught in codlemone-baited traps were used to develop action thresholds. Thresholds were based on the minimum cumulative number of moths per trap in ≥95% of traps in unsprayed plots with no fruit injury. Specific thresholds were established for the first insecticide spray targeting the start of egg hatch and for the first and second moth flights. The proportion of plots with mid-season fruit injury that had cumulative moth catches below the action threshold at first spray and at second moth flight was determined using the established action threshold and thresholds reduced incrementally to ≥1 moth per trap. Moth catches below the threshold at first spray were less common in plots with high levels of fruit injury (>0.3%) than in plots with low levels of fruit injury and more common with codlemone-baited traps than with pear ester-baited traps. An action threshold of ≥1 moth in a pear ester-baited trap at first spray eliminated the error in predicting fruit injury in plots at mid-season. Conversely, a high proportion of traps baited with either lure failed to predict low levels of fruit injury at harvest in unsprayed plots regardless of the cumulative moth threshold used during the second moth flight.

Wireless Sensor Networks (WSN) are groups of sensors, connected by communication links, spread over the area of interest, to perform a specific task. The network may get partitioned into clusters due to unanticipated simultaneous multiple node failures, and in such an event, will need to get reconnected to continue operation. These clusters are unaware of their own size, surviving nodes and links as well as the size and location of other survivor clusters. In our work, we propose a distributed and autonomous approach, namely Round Table Negotiation (RTN) approach, for reconnecting disjoint clusters in a short time. In this approach, each survivor cluster undergoes a self-discovery process, compiles its information and then sends a negotiator to participate in the round table negotiation and decision-making process to the round table around a pre-specified meeting point. All such negotiators exchange information and decide upon reconnection paths between the clusters and the nodes to involve in the reconnection process. The negotiators then return to their respective clusters and the reconnection process is carried out. Simulation results on wireless networks of varying sizes are presented. We show through a detailed comparison with existing methods that the proposed approach achieves reconnection in significantly lower time and is favorably comparable with respect to other performance metrics as well. In the second part of the work, we introduce the notion of importance of coverage area, that is, WSNs deployed in areas of varying coverage importance, classified by Importance Ranks (IR). In addition to connectivity restoration, the lost coverage of higher importance needs to be recovered, using the survivor nodes from the less important coverage area. This is done in two ways: recovery followed by reconnection and vice-versa, using the RTN approach. At the round table, the negotiation includes the assignment of importance based replacements for lost coverage along with reconnection paths and nodes to involve in the process. Once the negotiators return to their clusters, recovery and the reconnection processes are carried out. Simulation of the application of proposed modules on a randomly generated network is presented, along with comparison of these methods with that of original RTN approach over various random networks, to prove the applicability and to further study the efficacy.

The aim of the study was to determine the influence of different disturbances (both natural and anthropogenic) on species composition and stand structure of old-growth mixed mountain forests in the Western Carpathians. These stands are usually dominated by beech, fir and spruce, mixed in different proportions. The tree main species represent different growth strategies, and they compete against each other. The longevity of trees makes the factors influencing the stand structure difficult to identify, even during longitudinal studies conducted on permanent research plots. That is why dendroecological techniques, based upon the annual variability of tree rings, are commonly used to analyze the disturbance histories of old-growth stands. Dendroecological methods make it possible to reconstruct the stand history over several centuries in the past by analyzing the frequency, intensity, duration and spatial scale of disturbances causing the death of trees. Combining the dendroecological techniques with the detailed measurements of stand structure, snag volume, CWD volume, and the analyses of regeneration species composition and structure allows us to identify the factors responsible for the changes in dynamics of mixed mountain forests. Various disturbance agents affect some species selectively, while some disturbances promote the establishment of tree seedlings of specific species by modifying environmental conditions. Describing the disturbance regime requires a broad scope of data on stand structure, on dead wood and tree regeneration, while various factors affecting all the stages of tree growth should be taken into consideration. On the basis of the already published data from permanent sample plots, combined with the available disturbance history analyses from the Western Carpathians, three research hypotheses were formulated. 1. The species composition of mixed mountain forests has been changing for at least several decades. These directional changes are the consequence of simultaneous conifer species decline and expansion of beech. 2. The observed changes in species composition of mixed mountain forests are the effect of indirect anthropogenic influences, significantly changing tree growth conditions also in the forests that are usually considered natural or near-natural. Cumulative impact of these indirect influences leads to the decrease of fir share in the tree layer (spruce decline has also been observed recently),and it limits the representation of this species among seedlings and saplings. The final effect is the decrease of fir and spruce share in the forest stands. 3. Small disturbances, killing single trees or small groups of trees, and infrequent disturbances of medium size and intensity dominate the disturbance regime in mixed mountain forests. The present structure of beech-fir-spruce forests is shaped both by complex disturbance regime and indirect anthropogenic influences. The data were gathered in permanent sample plots in strictly protected areas of Babia Góra, Gorce, and Tatra National Parks, situated in the Western Carpathians. All plots were located in the old-growth forest stands representing Carpathian beech forest community. The results of the measurements of trees, snags, coarse woody debris (CWD) and tree regeneration were used for detailed description of changes in the species composition and structure of tree stands. Tree ring widths derived from increment cores were used to reconstruct the historical changes in tree growth trends of all main tree species, as well as the stand disturbance history within the past two to three hundred years. The analyses revealed complex disturbance history in all of the three forest stands. Intermediate disturbances of variable intensity occurred, frequently separated by the periods of low tree mortality lasting from several decades up to over one hundred years. The intervals between the disturbances were significantly shorter than the expected length of forest developmental cycle, in commonly used theories describing the dynamics of old-growth stands. During intermediate disturbances up to several dozen percent of canopy trees were killed. There were no signs of stand-replacing disturbances, killing all or nearly all of canopy trees. The periods of intense tree mortality were followed by subsequent periods of increased sapling recruitment. Variability in disturbance intensity is one of the mechanisms promoting the coexistence of beech and conifer species in mixed forests. The recruitment of conifer saplings depended on the presence of larger gaps, resulting from intermediate disturbances, while beech was more successful in the periods of low mortality. However, in the last few decades, beech seems to benefit from the period of intense fir mortality. This change results from the influence of long-term anthropogenic disturbances, affecting natural mechanisms that maintain the coexistence of different tree species and change natural disturbance regimes. Indirect anthropogenic influence on tree growth was clearly visible in the gradual decrease of fir increments in the twentieth century, resulting from the high level of air pollution in Europe. Synchronous decreases of fir tree rings’ widths were observed in all three of the sample plots, but the final outcomes depended on the fir age. In most cases, the damage to the foliage limited the competitive abilities of fir, but it did not cause a widespread increase in tree mortality, except for the oldest firs in the BGNP (Babia Góra National Park) plot. BGNP is located in the proximity of industrial agglomeration of Upper Silesia, and it could be exposed to higher level of air pollution than the other two plots. High level of fir regeneration browsing due to the deer overabundance and insufficient number of predators is the second clear indication of the indirect anthropogenic influence on mixed mountain forests. Game impact on fir regeneration is the most pronounced in Babia Góra forests, where fir was almost completely eliminated from the saplings. Deer browsing seems to be the main factor responsible for limiting the number of fir saplings and young fir trees, while the representation of fir among seedlings is high. The experiments conducted in fenced plots located in the mixed forests in BGNP proved that fir and sycamore were the most preferred by deer species among seedlings and saplings. In GNP (Gorce National Park) and TNP (Tatra National Park), the changes in species composition of tree regeneration are similar, but single firs or even small groups of firs are present among saplings. It seems that all of the analysed mixed beech-fir-spruce forests undergo directional changes, causing a systematic decrease in fir representation, and the expansion of beech. This tendency results from the indirect anthropogenic impact, past and present. Fir regeneration decline, alongside with the high level of spruce trees’ mortality in recent years, may lead to a significant decrease in conifers representation in the near future, and to the expansion of beech forests at the cost of mixed ones.

The main aim of this chapter is to monitor the cracking and damage assessment in steel-reinforced concrete (steel-RC) and glass fibre polymer-reinforced concrete (GFRP-RC) beams along with varying percentages of tension reinforcement ratio. Beam specimens measuring (150 × 230 × 2100) mm were tested using a four-point bending flexural test using a universal testing machine together with an AE monitoring system. Acoustic emission (AE) has been applied for the early monitoring of steel-RC and GFRP-RC structures using AE parameters such as cumulative AE hits, average frequency, rise angle, amplitude, duration and AE XY plots to evaluate the micro and macro cracking in the steel-RC and GFRP-RC beams specimens. The most popular applications of AE signal in structural health monitoring are specified on crack monitoring, quantifying the degree of damage, and crack classification. In this research, the results indicated that the average frequency and rise angle parameter of AE signal are applied to classify the types of cracks (flexural or shear cracks) that occur in steel-RC and GFRP-RC beams along with varying percentages of tension reinforcement ratio subjected to flexural loading. As a result of these findings, the AE approach may be used to examine crack monitoring and crack classification in steel and GFRP-RC beams with different percentages of tension reinforcement ratios.

The need to look at alternative platform concepts for the development of deep water prospects has lead to the Spar platform concept. The large Spar platform design used in the experimental study discussed in this article was a deep draft cylindrical hulled platform which had a central moonpool. It was designed to be secured to the seafloor using a spread mooring system. The Spar platform motions and wave runup on the Spar were measured and are characterized herein using cumulative probability plots and statistical moments. The plots show the nature and degree of non-Gaussianity. These plots together with the statistical moments provide in­sight into the degree of nonlinearity of the motions and wave platform interactions observed.

Abstract Present investment constraints in the industry require creative thinking, analysis and improved decision-making pattern in Brown field Development, Exploration and New Frontier investments. Value driven modeling and optimization provides an integrated approach where risking, volumetric uncertainties, schedule, cost, concepts, and fiscals are covered under one umbrella providing insights into risked value. This translates to probability distributions, e.g., hydrocarbon volume, reservoir parameters and their associated value (NPV) metrics (Fig.1). The case study is an opportunity in Shallow Water offshore Nigeria. Problem Statement Optimal use of scarce investment resources and the need to make robust decision with end-to-end view of the risks and subsurface uncertainty impact on the project value and promised volume. The methodology involves integration of subsurface analysis including risks/uncertainties of ten thousand (10K) realizations and stochastic surface network/Financial model analysis. These different analyses are integrated via a workflow to generate key insights in form of plots/data to enable business leaders make informed decisions having considered multiple possible realizations. These also provide insights in key drivers in an opportunity evaluation. The turnaround time is comparable to the processing of the discrete scenarios but adds much more value for the decision makers. The results were generated with the help of spotfire tool (smart analytics tool) to give flexibility in the handling of multiple plots in 3D to enable clear view of development cut offs. Key outcomes include the plot of EUR/Well vs Field UR, Cumulative probability vs NPV (mln $), Net pay (ft) vs Porosity, Fluid contact vs Productive area, etc. Clear cut offs linking subsurface outcomes to value indicators (NPV, IRR) are established. Decisions are made quicker and with clearer perspectives especially for exploration and new frontiers opportunities

Abstract This paper presents a new concept of Pseudo-Aquifer Index and a major departure from classical methods to estimate transient water influx using Kumar-Ramey equation employing reservoir average pressure obtained from transient tests for a central well in a constant pressure reservoir. The new method overcomes the two limitations of the conventional methods of van Everdingen-Hurst (1949), Carter-Tracy (1960), Fetkovich (1971), and similar other studies. These methods require apriori knowledge of (1) pressure history at the reservoir-aquifer boundary (oil-water contact or OWC) with time, and (2) aquifer characterization in terms of rock and fluid properties, depth, and geometric configuration. Such data for aquifer and OWC pressure history carry a high degree of uncertainty at the beginning of a newly discovered complex offshore or onshore reservoir development. Kumar-Ramey (1974) presented dimensionless water-influx (WeD) as a function of dimensionless average pressure and producing time which yields cumulative water-influx volumes as a fraction of cumulative reservoir withdrawal. Kumar (1977) also provided the dimensionless pressure at the reservoir aquifer boundary with time. Plots of dimensionless average pressure, dimensionless boundary pressures at the OWC, and cumulative water influx function (WeD) are presented as a function of producing times for the three cases of pseudo-aquifer-index of 0.25, 0.50, and 1.0. Some of this data is obtained from Kumar (1977) and is transformed into polynomial equations. Two examples show the applications, and compare transient water-influx results with those obtained from van Everdingen-Hurst method. A log-log type curve of dimensionless average pressure and time is included for determination of reservoir properties when average pressure is known A considerable advantage of the new method is its simplicity, generality, ease in use, and implementation in reservoir engineering software and simulation when compared to conventional methods. This study is also the first to provide a systemic characterization of transient boundary (OWC) pressures in closed and partial water drive reservoirs.

Abstract Geological folding/faulting may create naturally fractured reservoirs containing a semi-parallel system of sparsely-spaced fracture corridors. The pressure behavior of wells completed either in highly conductive corridors (fracture wells) or in the exclusion zone (matrix wells) would be quite different. In this study, a unique simulation model has been built for corridor type naturally fractured reservoirs by combining a local model of fracture well or matrix well with adjacent fracture corridor(s) and a “homogenized” global model of the remaining corridor network. The global model generalizes the corridor network using the single-porosity and radial permeability approach, which is verified as being sufficiently accurate. Pattern recognition technique is used to analyze diagnostic plots of pressure drawdown generated by simulated flow tests with commercial software (CMG). This study aims to build a new simulation model for corridor-type NFRs and apply the well testing technique to differentiate corridor-type NFRs from conventional NFRs, detect the well’s location, and estimate reservoir properties. This study also employs cumulative logit statistics to assess the accuracy of the estimated well-to-corridor distance.

A distance is defined as a measure of dissimilarity between two reservoir models. There have been many distances proposed for fast modeling. However, some distances cause distortion or loss in original permeability distribution of models. To avoid such problems, this study proposes a pattern recognition based distance. The distance is defined by the difference of correlation coefficients between ensemble models. From multi-dimensional scaling, initial 400 ensembles are presented on 2D plane using the distance. Then 10 groups are made by K-medoids clustering. After comparing oil production from each centroid and that of the reference field, 100 models are selected around the best centroid. We validate the clustering by comparing the uncertainty range of 100, 50, and 20 ensemble members sampled from the initial 400 models in box plots and cumulative distribution functions. For a history matching and reservoir characterization, ensemble smoother is applied to the 100 models selected. The proposed method takes only 25% time for simulation showing reliable results compared with the initial 400 models.

The concepts of limit loads and plastic loads for piping components are outlined. The difficulty associated with specifying reliable definitions for these quantities is addressed. These difficulties include the selection of a deformation parameter, the selection of a location within the structure where this deformation is to be calculated or measured and the criterion to be used to assess if the deformation is sufficient for the structure to be considered to have reached its limit or plastic load. An alternative method based upon plastic work has recently been advocated [1]. This definition is based upon the plastic work that may be calculated during a routine finite element computation. Having plotted the cumulative plastic work against a load parameter, it was shown possible to identify levels at which collapse mechanisms form and where gross plastic deformation becomes evident. The present work attempts to add some precision to this definition. This has been done by determining the important geometric parameters and forming non-dimensional quantities to allow new plots in which the limit or plastic loads can be extracted directly and without any ambiguity. The technique is shown to be reliable for cracked and uncracked plain cylinders and cracked and uncracked piping branch junctions.

This paper details application of a 2-parameter Weibull maximum likelihood estimation (MLE) method to optical fiber breaking stress data. Optical fiber is used in a broad range of telecommunications applications and its associated performance in fabricated component assemblies is of critical importance to the proper functioning of telecom networks. Fiber optic components incorporating stripped optical fiber include optical couplers, optical splitters, WDM devices, connectors, and mechanical and fusion splices. The strength of optical fiber in component assemblies is dependent upon numerous aspects of the fabrication process. These include the fiber coating stripping process, fiber cleaning after stripping, any manual handling of the fiber after stripping, and the time period after fiber stripping until the fiber is inserted and potted into a component or subjected to mechanical or fusion splice processes. The ambient moisture content of the air is a critical parameter affecting the resultant strength of stripped fiber. The fabrication and assembly processes utilized to produce component assemblies can cause damage to the fiber and the resultant creation of macro defects. From a reliability and analysis perspective being able to separate the effects of fabrication-induced macro defects from those due to intrinsic micro flaws present in the unstripped optical fiber is critical. The Weibull statistical analysis method permits identification of distinct fiber breaking stress regions associated with intrinsic fiber strength vs. macro-defects created by stripping and fabrication processes. The Weibull analysis is most effectively applied to fiber breaking stress data in the lower 25% quartile since this stress region will be of most interest from a reliability perspective. Another significant benefit derived from the Weibull analysis is the ability to predict cumulative failure rates for any selected values of fiber breaking stress. The predictive capability of the Weibull model provides more useful information regarding the lower breaking stress region than conventional statistical analysis methods such as analysis of variance (ANOVA). The Weibull MLE data analysis method provides more conservative and robust results relative to other Weibull analysis methods such as Median Rank Regression (MRR) [1]. The Weibull MLE analysis method was applied to individual and cumulative fiber breaking stress data sets generated from 10 new fiber strippers of a selected specific type. The objective of these analyses was to provide trustworthy predictions of Weibull unreliability for the selected stripper type in the lower modal breaking stress region of interest for component end-use performance. This paper details the following: • methodology for producing the initial Weibull data plots, • identification of modal regions associated with fiber macro and intrinsic defects, • selection of a representative breaking stress region for application of the Weibull analysis, • generation and interpretation of the two Weibull parameters (β and η), and • prediction of cumulative failure rate or unreliability confidence intervals (C.I.’s) for selected fiber breaking stress values. This study showed that combining the data from all 10 fiber strippers into a cumulative data set and then performing the Weibull MLE analysis is the preferred approach. This method provides the best and most comprehensive definition of the lower fiber breaking stress modal region and more trustworthy predictions of Weibull unreliability at critical selected independent variable values of 50 and 100 kpsi.

In response to the technical challenges faced by aging plant systems and components at nuclear power plants (NPP), the Electric Power Research Institute (EPRI) has a product entitled Integrated Life Cycle Management (ILCM). The ILCM software is a quantitative tool that supports capital asset and component replacement decision-making at NPPs. ILCM is comprised of models that predict the probability of failure (PoF) over time for various high-value components such as steam generators, turbines, generators, etc. The PoF models allow the user to schedule replacements at the optimum time, thereby reducing unplanned equipment shutdowns and costs. This paper describes a mathematical model that was developed for critical heat exchangers in a power plant. The heat exchanger model calculates the probability of the tubes, shell, or internals failing individually, and then accumulates the failures across the heat exchanger sub-components. The dominant degradation mechanisms addressed by the model include stress corrosion cracking, wear, microbiologically influenced corrosion, flow accelerated corrosion, and particle-induced erosion. The heat exchanger model combines physics-based algorithms and operating experience distributions to predict the cumulative PoF over time. The model is applicable to shell and tube heat exchangers and air-to-water heat exchangers. Many different types of fluids including open cycle fresh water, closed cycle fresh water, sea water, brackish water, air, closed cooling water, steam, oil, primary water, and condensate are included. Examples of PoF over time plots are also provided for different fluid types and operating conditions.

Abstract Mangala field (India) is one of the largest polymer flooding fields in the world with hundreds of wells and waxy crude oil. Field-scale optimization of polymer injection is challenging due to the geologic heterogeneity and operational constraints. This paper demonstrates an application of streamline-based injection optimization for the Mangala field. The paper will cover the mathematical foundation, optimization studies, and considerations for field implementation. Our field application consists of five key stages: i) Problem framing. This includes defining optimization objectives, tuning parameters and constraints such as optimization start/end times, schedule update intervals, field rate targets, and injection/production limits for each well. ii) Rate optimization by streamline method. The optimizer iteratively reallocates the well rates, diverting the injected fluid to high efficiency injector-producer pairs located in upswept oil regions. iii) Optimal schedule interpretation. The rate change, flow pattern alteration and injection efficiency improvement are systematically examined, providing decision makers physical explanations of the suggested rate changes. iv) Selection of key injectors for field implementation. To avoid the risk of large-scale field implementation, limited number of injectors contributing the most to the oil production increase or water production decrease are selected for initial deployment. v) Potential field implementation and validation of the proposed plan based on field observations. Data from offset producers surrounding the rate-reallocated injectors can help evaluate oil production improvement or alleviated decline. The optimized rate schedule is first compared with the current schedule in the field, honoring the field total liquid injection/production rates. The optimized case redistributes the rate allocation among high efficiency injectors within predefined bottom hole pressure and rate constraints. The cumulative oil production increase for the short-term optimization period, 11 months, is 0.66 MMbbl. The efficiency plots show efficient utilization of injected fluid after optimization and the bubble plots and streamline maps indicate that the optimizer alters the flow pattern for a better sweep of the remaining oil. Based on the full field optimization, 20 key injectors are selected for field implementation. Numerical simulation shows that 75% of total oil gain can be achieved from optimization of the key injectors. For field validation, offset producers are expected to show an arrest in the oil decline rate due to improved pressure support and, also reduced water cut increase after field implementation.

Breeding bird surveys were initiated on Wilson’s Creek National Monument, Missouri, in 2008 to assess temporal changes in the species composition and abundance of birds on the park and to improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 38 variable circular plots located on a systematic grid of 400 x 400-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-min sampling period were recorded. In the 13 years since initiating our breeding bird survey, birds were surveyed on as many of the 38 variable circular plots as possible each year, resulting in 444 cumulative plot visits. Surveys have yielded records for 119 different species of birds. Ninety-eight of the species recorded are classified as permanent or summer residents to the area, 18 are classified as transients in the area, and 3 as winter residents to the area. Eight breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region in which Wilson’s Creek National Battlefield is located. Of the 98 breeding species recorded, 12 species in grassland habitat and 15 in woodland habitat occurred in numbers large enough to calculate annual abundances with some degree of confidence. Trends in abundance were classified as uncertain for most species, which means that no significant increases or decreases occurred but it is not certain that trends were <5% per year. The Indigo Bunting (Passerina cyanea) population in grassland habitat was stable. The Eastern Towhee (Pipilo erythrophthalmus) and Eastern Wood-pewee (Contopus virens) populations in woodland habitat were in moderate decline. Comparing population trends on the park with regional trends for the Central Hardwoods Bird Conservation Region suggests that the bird community at Wilson’s Creek National Battlefield is faring similarly to that of the region as a whole. Stable diversity, richness, and evenness values suggest that the park’s habitat has remained consistent in its ability to meet the requirements of many of the park’s breeding bird species. Any decline in species richness could reflect habitat management practices, but it could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on Wilson’s Creek National Battlefield as management and weather and climatic conditions change is essential for park management.

Breeding bird surveys were initiated on Pea Ridge National Military Park, Arkansas in 2008 to assess temporal changes in the species composition and abundance of birds on the park. These data also improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 99 variable circular plots located on a systematic grid of 400 x 400-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-minute sampling period were recorded. We surveyed for breeding birds in eight of the last 14 years on as many of the 99 variable circular plots as possible each year, resulting in 592 cumulative plot visits. Surveys have yielded records for 111 different species of birds. Ninety-three of the species recorded are classified as permanent or summer residents to the area, 11 as winter residents to the area, six as transients in the area, and one as a migrant through the area. Nine breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region Pea Ridge National Military Park is located within. Of the 93 breeding species recorded, 4 species occurred in grassland and 11 in woodland habitats in numbers large enough to calculate annual abundances with some degree of confidence. However, only the Blue-gray Gnatcatcher (Polioptila caerulea), Eastern Wood-pewee (Contopus virens), Red-eyed Vireo (Vireo olivaceus), and Tufted Titmouse (Baeolophus bicolor) in woodland habitats demonstrated any trends (moderate to strong increases) in abundance. Trends in abundance were classified as uncertain for the rest of the species in both grassland and woodland habitats, which means that no significant increases or decreases occurred, but it is not certain that trends were < 5% per year. Comparisons of population trends on the park with regional trends for the Central Hardwoods Bird Conservation Region suggest that the bird community at Pea Ridge National Military Park is faring similarly to or slightly better than that of the region as a whole. Stable diversity, richness, and evenness values suggest that the park’s habitat has remained consistent in its ability to meet the requirements of many of the park’s breeding bird species. Any increase or decline in species richness could reflect habitat management practices but could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on Pea Ridge National Military Park as management and climatic conditions change is essential for park management. - -

Breeding bird surveys were initiated on George Washington Carver National Monument, Missouri, in 2008 to assess temporal changes in the species composition and abundance of birds on the park and to improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 70 variable circular plots located on a systematic grid of 100 x 100-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-min sampling period were recorded. In the 13 years since initiating our breeding bird surveys on the park, birds were surveyed on as many of the 70 variable circular plots as possible each year, resulting in 520 cumulative plot visits. Surveys have yielded records for 100 different species of birds. Ninety-seven of the species recorded are classified as permanent or summer residents to the area, two are classified as transients in the area, and one as a winter resident to the area. Six breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region in which George Washington Carver National Monument is located. Of the 97 breeding species recorded, ten species in grassland habitat and six in woodland habitat occurred in numbers large enough to calculate annual abundances with some degree of confidence. Trends in abundance were classified as uncertain for most species, which means that there were no significant increases or decreases, but it is not certain that trends were < 5% per year. The Northern Cardinal (Cardinalis cardinalis) in woodland habitat was stable. The Eastern Meadowlark (Sturnella magna) in grassland habitat was in moderate decline, and the Northern Bobwhite (Colinus virginianus) in grassland habitat was in steep decline. Comparing population trends (i.e., changes in population size over time) on the park with regional trends for the Central Hardwoods Bird Conservation Region suggests that the bird community at George Washington Carver National Monument is faring similarly to that of the region as a whole. Trends in the park’s popula-tions of Field Sparrow (Spizella pusilla) and Indigo Bunting (Passerina cyanea) in grassland habitat and Carolina Wren (Thryothorus ludovicianus) in woodland habitat were uncertain, whereas they declined significantly in the larger region, which could be a result of management on George Washington Carver National Monument. Red-bellied Woodpecker (Melanerpes carolinus) population trends, while uncertain in grassland habitat on the park, increased significantly in the region. The Red-bellied Woodpecker utilizes trees for foraging, which are sparse in the grassland habitat on the park. Declining diversity and richness values suggest that park habitat is declining in its ability to meet the requirements of many of the park’s breeding bird species. This decline in species richness could reflect habitat management practices, but it could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on George Washington Carver National Monument as management and weather and climatic conditions change is essential for park management.

The objective of this one-year project was to show whether a significant correlation can be established between the decreasing infiltration rate of the soil, during simulated rainstorm, and a following increase in the reflectance of the crusting soil. The project was supposed to be conducted under laboratory conditions, using at least three types of soils from each country. The general goal of this work was to develop a method for measuring the soil infiltration rate in-situ, solely from the reflectance readings, using a spectrometer. Loss of rain and irrigation water from cultivated fields is a matter of great concern, especially in arid, semi-arid regions, e.g. much of Israel and vast area in US, where water is a limiting factor for crop production. A major reason for runoff of rain and overhead irrigation water is the structural crust that is generated over a bare soils surface during rainfall or overhead irrigation events and reduces its infiltration rate (IR), considerably. IR data is essential for predicting the amount of percolating rainwater and runoff. Available information on in situ infiltration rate and crust strength is necessary for the farmers to consider: when it is necessary to cultivate for breaking the soil crust, crust strength and seedlings emergence, precision farming, etc. To date, soil IR is measured in the laboratory and in small-scale field plots, using rainfall simulators. This method is tedious and consumes considerable resources. Therefore, an available, non-destructive-in situ methods for soil IR and soil crusting levels evaluations, are essential for the verification of infiltration and runoff models and the evaluation of the amount of available water in the soil. In this research, soil samples from the US and Israel were subjected to simulated rainstorms of increasing levels of cumulative energies, during which IR (crusting levels) were measured. The soils from the US were studied simultaneously in the US and in Israel in order to compare the effect of the methodology on the results. The soil surface reflectance was remotely measured, using laboratory and portable spectrometers in the VIS-NIR and SWIR spectral region (0.4-2.5mm). A correlation coefficient spectra in which the wavelength, consisting of the higher correlation, was selected to hold the highest linear correlation between the spectroscopy and the infiltration rate. There does not appear to be a single wavelength that will be best for all soils. The results with the six soils in both countries indeed showed that there is a significant correlation between the infiltration rate of crusted soils and their reflectance values. Regarding the wavelength with the highest correlation for each soil, it is likely that either a combined analysis with more then one wavelength or several "best" wavelengths will be found that will provide useful data on soil surface condition and infiltration rate. The product of this work will serve as a model for predicting infiltration rate and crusting levels solely from the reflectance readings. Developing the aforementioned methodologies will allow increased utilization of rain and irrigation water, reduced runoff, floods and soil erosion hazards, reduced seedlings emergence problems and increased plants stand and yields.

Cette étude porte sur une des innovations contemporaines liées à l’économie de la publication scientifique : les accords dits transformants, un objet relativement circonscrit au sein des relations entre consortiums de bibliothèques et éditeurs scientifiques, et temporellement situé entre 2015 et 2020. Ce type d’accords a pour objectif affiché d’organiser la transition du modèle traditionnel de l’abonnement à des revues (souvent proposées par regroupements thématiques ou collections) vers celui de l’accès ouvert en opérant une réaffectation des budgets qui y sont consacrés. Notre travail d’analyse sociologique constitue une première étude systématique de cet objet, fondée sur la recension de 197 accords. Le corpus ainsi constitué inclut des accords caractérisés par la coprésence d’une composante d’abonnement et d’une composante de publication en accès ouvert, même minimale (« jetons » de publication offerts, réduction sur les APC...). En conséquence, ont été exclus de l’analyse les accords portant uniquement sur du financement centralisé de publication en accès ouvert, que ce soit avec des éditeurs ne proposant que des revues avec paiement par l’auteur (PLOS, Frontiers, MDPI...) ou des éditeurs dont une partie du catalogue est constitué de revues en accès ouvert. L’accord le plus ancien de notre corpus a été signé en 2010, les plus récents en 2020 – les accords ne commençant qu’en 2021, même annoncés au cours de l’étude, n’ont pas été retenus. Plusieurs résultats se dégagent de notre analyse. Tout d’abord, on note une grande diversité des acteurs impliqués avec 22 pays et 39 éditeurs, même si certains consortiums (Pays-Bas, Suède, Autriche, Allemagne) et éditeurs (CUP, Elsevier, RSC, Springer) en ont signé beaucoup plus que d’autres. Ensuite, la durée des accords, comprise entre une et six années, révèle une distribution très inégalitaire, avec plus de la moitié des accords (103) signés pour 3 ans, ainsi qu’une faible proportion pour 4 ans ou plus (22 accords). Enfin, en dépit d’appels répétés à la transparence, moins de la moitié des accords (96) ont un texte accessible au moment de cette étude, sans qu’on puisse observer une tendance récente à une plus grande disponibilité. L’analyse montre également des degrés d’ouverture très variables, allant d’une simple information sur le répertoire ESAC en passant par la mise à disposition d’un format annotable jusqu’à l’attribution d’un DOI et d’une licence de réutilisation (CC-BY), en incluant le détail des sommes monétaires. Parmi les 96 accords disponibles, dont 47 signés en 2020, 62 ont fait l’objet d’une analyse en profondeur. C’est à notre connaissance la première analyse à cette échelle, sur un type de matériel non seulement inédit, mais qui était auparavant soumis à des clauses de confidentialité. Fondée sur une lecture minutieuse, l’étude décrit de manière fine leurs propriétés, depuis la matérialité du document jusqu’aux formules financières, en passant par leur morphologie et l’ensemble des droits et devoirs des parties. Les contenus des accords sont donc analysés comme une collection dont nous cherchons à déterminer les points communs et les variations, à travers des codages explicites sur certaines de leurs caractéristiques. L’étude pointe également des incertitudes, et notamment leur caractère « transitionnel », qui demeure fortement discuté. D’un point de vue morphologique, les accords montrent une grande diversité en matière de taille (de 7 à 488 pages) et de structure. Néanmoins, par définition, ils articulent tous deux objets essentiels : d’une part, les conditions de réalisation d’une lecture d’articles de revues, sous forme d’abonnement, mêlant des préoccupations d’accès et de sécurité ; d’autre part, les modalités de publication en accès ouvert, articulant la gestion d’un nouveau type de workflow à toute une série d’options possibles. Parmi ces options, mentionnons notamment le périmètre des revues considérées (hybrides et/ou accès ouvert), les licences disponibles, le degré d’obligation de cette publication, les auteurs éligibles ou le volume d’articles publiables. L’un des résultats les plus importants de cette analyse approfondie est la mise au jour d’un découplage presque complet, au sein même des accords, entre l’objet abonnement et l’objet publication. Bien entendu, l’abonnement est systématiquement configuré dans un monde fermé, soumis à paiement qui déclenche des séries d’identification des circulations légitimes tant du contenu informationnel que des usagers. Il insiste notamment sur les interdictions de réutilisation ou même de copie des articles scientifiques. À l’opposé, la publication en accès ouvert est attachée à un monde régi par l’accès gratuit au contenu, ce qui induit des préoccupations de gestion du workflow et des modalités d’accessibilité. De plus, les différents éléments constitutifs de ces objets contractuels ne sont pas couplés : d’un côté, les lecteurs sont constitués de l’ensemble des membres des institutions abonnées, de l’autre, seuls les auteurs correspondants (« corresponding authors ») sont concernés ; les listes de revues accessibles à la lecture et celles réservées à la publication en accès ouvert sont le plus souvent distinctes ; les workflows ont des objectifs et des organisations matérielles totalement différentes, etc. L’articulation entre les deux objets contractuels relève uniquement d’une formule de distribution financière qui, outre des combinaisons particulières entre l’un et l’autre, permet d’attribuer des étiquettes distinctes aux accords (offset agreement, publish & read, read & publish, read & free articles, read & discount). Au-delà de cette distribution, l’étude des arrangements financiers montre une gamme de dispositions allant d’une prévisibilité budgétaire totale, donc identique aux accords d’abonnement antérieurs, à une incertitude sur le volume de publication ou sur le montant définitif des sommes échangées. Les modalités concrètes de calcul des montants associés à la publication en accès ouvert sont relativement variées. S’il existe effectivement des formules récurrentes (volume d’articles multiplié par un prix individuel, reprise de la moyenne des sommes totales d’APC des années précédentes...), le calcul des sommes en jeu est toujours le résultat d’une négociation singulière entre un consortium et un éditeur scientifique, et aboutit parfois à des formules originales et complexes. À ce titre, l’espace des possibles en matière de formules financières n’est jamais totalement clos. Par ailleurs, la volonté des consortiums d’opérer une « transformation » de leurs accords vers la publication à coût constant renvoie à des définitions diversifiées du « coût » (inclusion ou non des dépenses d’APC préexistantes) et de la constance (admission ou pas d’une « inflation » à 2 ou 3%). De plus, nous n’avons observé aucune disposition contractuelle permettant d’anticiper les sommes en jeu au-delà de l’horizon temporel de l’accord courant. La grande diversité des accords provient d’une part des conditions initiales des relations entre consortiums et éditeurs scientifiques – les sommes dépensées en abonnement étant le point de départ des nouveaux accords –, d’autre part des objectifs de chaque partie. Même si cette étude excluait volontairement les négociations, les accords portent des traces de ces objectifs. Ainsi, de nombreux accords sont de nature explicitement expérimentale, quand certains visent un contrôle budgétaire strict, ou d’autres ambitionnent, dans la période plus récente, la publication du plus grand nombre possible d’articles en accès ouvert. C’est dans ce dernier cas qu’on touche à l’ambiguïté des attentes générales sur les accords transformants. En effet, pour les consortiums, la dimension « transformante » consiste essentiellement à transférer les sommes traditionnellement allouées à l’abonnement vers la publication en accès ouvert. Mais l’objectif n’est jamais de transformer le modèle économique des revues, c'est-à-dire de faire basculer des revues sous abonnement ou hybrides en revues entièrement en accès ouvert. D’ailleurs, aucune clause ne vise une telle fin – à l’exception du modèle d’accord proposé par l’éditeur ACM. Du côté des éditeurs, et notamment de Springer, le caractère cumulatif des accords nationaux passés vise à projeter un monde de la publication où l’accès ouvert devient de fait quantitativement très dominant, sans pour autant modifier de manière pérenne le modèle économique de leurs revues. Notre étude montre que les accords transformants actuels ne permettent pas d’assurer de manière durable une transition de l’économie de la publication vers l’accès ouvert, dans la mesure où ils n’offrent pas de garantie sur le contrôle des dépenses ni sur la pérennité de l’ouverture des contenus. L’avenir des relations entre consortium et éditeur demeure largement indéterminé.Cette étude porte sur une des innovations contemporaines liées à l’économie de la publication scientifique : les accords dits transformants, un objet relativement circonscrit au sein des relations entre consortiums de bibliothèques et éditeurs scientifiques, et temporellement situé entre 2015 et 2020. Ce type d’accords a pour objectif affiché d’organiser la transition du modèle traditionnel de l’abonnement à des revues (souvent proposées par regroupements thématiques ou collections) vers celui de l’accès ouvert en opérant une réaffectation des budgets qui y sont consacrés. Notre travail d’analyse sociologique constitue une première étude systématique de cet objet, fondée sur la recension de 197 accords. Le corpus ainsi constitué inclut des accords caractérisés par la coprésence d’une composante d’abonnement et d’une composante de publication en accès ouvert, même minimale (« jetons » de publication offerts, réduction sur les APC...). En conséquence, ont été exclus de l’analyse les accords portant uniquement sur du financement centralisé de publication en accès ouvert, que ce soit avec des éditeurs ne proposant que des revues avec paiement par l’auteur (PLOS, Frontiers, MDPI...) ou des éditeurs dont une partie du catalogue est constitué de revues en accès ouvert. L’accord le plus ancien de notre corpus a été signé en 2010, les plus récents en 2020 – les accords ne commençant qu’en 2021, même annoncés au cours de l’étude, n’ont pas été retenus. Plusieurs résultats se dégagent de notre analyse. Tout d’abord, on note une grande diversité des acteurs impliqués avec 22 pays et 39 éditeurs, même si certains consortiums (Pays-Bas, Suède, Autriche, Allemagne) et éditeurs (CUP, Elsevier, RSC, Springer) en ont signé beaucoup plus que d’autres. Ensuite, la durée des accords, comprise entre une et six années, révèle une distribution très inégalitaire, avec plus de la moitié des accords (103) signés pour 3 ans, ainsi qu’une faible proportion pour 4 ans ou plus (22 accords). Enfin, en dépit d’appels répétés à la transparence, moins de la moitié des accords (96) ont un texte accessible au moment de cette étude, sans qu’on puisse observer une tendance récente à une plus grande disponibilité. L’analyse montre également des degrés d’ouverture très variables, allant d’une simple information sur le répertoire ESAC en passant par la mise à disposition d’un format annotable jusqu’à l’attribution d’un DOI et d’une licence de réutilisation (CC-BY), en incluant le détail des sommes monétaires. Parmi les 96 accords disponibles, dont 47 signés en 2020, 62 ont fait l’objet d’une analyse en profondeur. C’est à notre connaissance la première analyse à cette échelle, sur un type de matériel non seulement inédit, mais qui était auparavant soumis à des clauses de confidentialité. Fondée sur une lecture minutieuse, l’étude décrit de manière fine leurs propriétés, depuis la matérialité du document jusqu’aux formules financières, en passant par leur morphologie et l’ensemble des droits et devoirs des parties. Les contenus des accords sont donc analysés comme une collection dont nous cherchons à déterminer les points communs et les variations, à travers des codages explicites sur certaines de leurs caractéristiques. L’étude pointe également des incertitudes, et notamment leur caractère « transitionnel », qui demeure fortement discuté. D’un point de vue morphologique, les accords montrent une grande diversité en matière de taille (de 7 à 488 pages) et de structure. Néanmoins, par définition, ils articulent tous deux objets essentiels : d’une part, les conditions de réalisation d’une lecture d’articles de revues, sous forme d’abonnement, mêlant des préoccupations d’accès et de sécurité ; d’autre part, les modalités de publication en accès ouvert, articulant la gestion d’un nouveau type de workflow à toute une série d’options possibles. Parmi ces options, mentionnons notamment le périmètre des revues considérées (hybrides et/ou accès ouvert), les licences disponibles, le degré d’obligation de cette publication, les auteurs éligibles ou le volume d’articles publiables. L’un des résultats les plus importants de cette analyse approfondie est la mise au jour d’un découplage presque complet, au sein même des accords, entre l’objet abonnement et l’objet publication. Bien entendu, l’abonnement est systématiquement configuré dans un monde fermé, soumis à paiement qui déclenche des séries d’identification des circulations légitimes tant du contenu informationnel que des usagers. Il insiste notamment sur les interdictions de réutilisation ou même de copie des articles scientifiques. À l’opposé, la publication en accès ouvert est attachée à un monde régi par l’accès gratuit au contenu, ce qui induit des préoccupations de gestion du workflow et des modalités d’accessibilité. De plus, les différents éléments constitutifs de ces objets contractuels ne sont pas couplés : d’un côté, les lecteurs sont constitués de l’ensemble des membres des institutions abonnées, de l’autre, seuls les auteurs correspondants (« corresponding authors ») sont concernés ; les listes de revues accessibles à la lecture et celles réservées à la publication en accès ouvert sont le plus souvent distinctes ; les workflows ont des objectifs et des organisations matérielles totalement différentes, etc. L’articulation entre les deux objets contractuels relève uniquement d’une formule de distribution financière qui, outre des combinaisons particulières entre l’un et l’autre, permet d’attribuer des étiquettes distinctes aux accords (offset agreement, publish & read, read & publish, read & free articles, read & discount). Au-delà de cette distribution, l’étude des arrangements financiers montre une gamme de dispositions allant d’une prévisibilité budgétaire totale, donc identique aux accords d’abonnement antérieurs, à une incertitude sur le volume de publication ou sur le montant définitif des sommes échangées. Les modalités concrètes de calcul des montants associés à la publication en accès ouvert sont relativement variées. S’il existe effectivement des formules récurrentes (volume d’articles multiplié par un prix individuel, reprise de la moyenne des sommes totales d’APC des années précédentes...), le calcul des sommes en jeu est toujours le résultat d’une négociation singulière entre un consortium et un éditeur scientifique, et aboutit parfois à des formules originales et complexes. À ce titre, l’espace des possibles en matière de formules financières n’est jamais totalement clos. Par ailleurs, la volonté des consortiums d’opérer une « transformation » de leurs accords vers la publication à coût constant renvoie à des définitions diversifiées du « coût » (inclusion ou non des dépenses d’APC préexistantes) et de la constance (admission ou pas d’une « inflation » à 2 ou 3%). De plus, nous n’avons observé aucune disposition contractuelle permettant d’anticiper les sommes en jeu au-delà de l’horizon temporel de l’accord courant. La grande diversité des accords provient d’une part des conditions initiales des relations entre consortiums et éditeurs scientifiques – les sommes dépensées en abonnement étant le point de départ des nouveaux accords –, d’autre part des objectifs de chaque partie. Même si cette étude excluait volontairement les négociations, les accords portent des traces de ces objectifs. Ainsi, de nombreux accords sont de nature explicitement expérimentale, quand certains visent un contrôle budgétaire strict, ou d’autres ambitionnent, dans la période plus récente, la publication du plus grand nombre possible d’articles en accès ouvert. C’est dans ce dernier cas qu’on touche à l’ambiguïté des attentes générales sur les accords transformants. En effet, pour les consortiums, la dimension « transformante » consiste essentiellement à transférer les sommes traditionnellement allouées à l’abonnement vers la publication en accès ouvert. Mais l’objectif n’est jamais de transformer le modèle économique des revues, c'est-à-dire de faire basculer des revues sous abonnement ou hybrides en revues entièrement en accès ouvert. D’ailleurs, aucune clause ne vise une telle fin – à l’exception du modèle d’accord proposé par l’éditeur ACM. Du côté des éditeurs, et notamment de Springer, le caractère cumulatif des accords nationaux passés vise à projeter un monde de la publication où l’accès ouvert devient de fait quantitativement très dominant, sans pour autant modifier de manière pérenne le modèle économique de leurs revues. Notre étude montre que les accords transformants actuels ne permettent pas d’assurer de manière durable une transition de l’économie de la publication vers l’accès ouvert, dans la mesure où ils n’offrent pas de garantie sur le contrôle des dépenses ni sur la pérennité de l’ouverture des contenus. L’avenir des relations entre consortium et éditeur demeure largement indéterminé.