bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Gas Adsorption in Marcellus Shale With Langmuir and BET Isotherms
Authors: Yu Wei , Sepehrnoori Kamy , Patzek Tadeusz W.
Published: January 2016

Production from shale-gas reservoirs plays an important role in natural-gas supply in the United States. Horizontal drilling and multistage hydraulic fracturing are the two key enabling technologies for the economic development of these shale-gas reservoirs. It is believed that gas in shale reservoirs is mainly composed of free gas within fractures and pores and adsorbed gas in organic matter (kerogen). It is generally assumed in the literature that the monolayer Langmuir isotherm describes gas-adsorption behavior in shale-gas reservoirs. However, in this work, we analyzed four experimental measurements of methane adsorption from the Marcellus Shale core samples that deviate from the Langmuir isotherm, but obey the Brunauer-Emmett-Teller (BET) isotherm. To the best of our knowledge, it is the first time to find that methane adsorption in a shale-gas reservoir behaves similar to multilayer adsorption. Consequently, investigation of this specific gas-desorption effect is important for accurate evaluation of well performance and completion effectiveness in shale-gas reservoirs on the basis of the BET isotherm. The difference in calculating original gas in place (OGIP) on the basis of both isotherms is discussed. We also performed history matching with one production well from the Marcellus Shale and evaluated the contribution of gas desorption to the well's performance. History matching shows that gas adsorption obeying the BET isotherm contributes more to overall gas recovery than gas adsorption obeying the Langmuir isotherm, especially at early time in production. This work provides better understanding of gas desorption in shale-gas reservoirs and updates our current analytical and numerical models for simulation of shale-gas production.
Fully Coupled Hydromechanical Simulation of Hydraulic Fracturing in 3D Discrete-Fracture Networks
Authors: McClure Mark W. , Babazadeh Mohsen , Shiozawa Sogo , Huang Jian
Published: January 2016

We developed a hydraulic-fracturing simulator that implicitly couples fluid flow with the stresses induced by fracture deformation in large, complex, 3D discrete-fracture networks (DFNs). The code is efficient enough to perform field-scale simulations of hydraulic fracturing in DFNs containing thousands of fractures, without relying on distributed-memory parallelization. The simulator can describe propagation of hydraulic fractures and opening and shear stimulation of natural fractures. Fracture elements can open or slide, depending on their stress state, fluid pressure, and mechanical properties. Fracture sliding occurs in the direction of maximum resolved shear stress. Nonlinear empirical equations are used to relate normal stress, fracture opening, and fracture sliding to fracture aperture and transmissivity. Fluid leakoff is treated with a semianalytical 1D leakoff model that accounts for changing pressure in the fracture over time. Fracture propagation is modeled with linear-elastic fracture mechanics. The Forchheimer equation (Forchheimer 1901) is used to simulate non-Darcy pressure drop in the fractures because of high flow rate. A crossing criterion is implemented that predicts whether propagating hydraulic fractures will cross natural fractures or terminate against them, depending on orientation and stress anisotropy. Height containment of propagating hydraulic fractures between bedding layers can be modeled with a vertically heterogeneous stress field or by explicitly imposing hydraulic-fracture-height containment as a model assumption. Limitations of the model are that all fractures must be vertical; the mechanical calculations assume a linearly elastic and homogeneous medium; proppant transport is not included; and the locations of potentially forming hydraulic fractures must be specified in advance. Simulations were performed of a single propagating hydraulic fracture with and without leakoff to validate the code against classical analytical solutions. Field-scale simulations were performed of hydraulic fracturing in a densely naturally fractured formation. The simulations demonstrate how interaction with natural fractures in the formation can help explain the high net pressures, relatively short fracture lengths, and broad regions of microseismicity that are often observed in the field during stimulation in low-permeability formations, and that are not predicted by classical hydraulic-fracturing models. Depending on input parameters, our simulations predicted a variety of stimulation behaviors, from long hydraulic fractures with minimal leakoff into surrounding fractures to broad regions of dense fracturing with a branching network of many natural and newly formed fractures.
Pioneering Utilization of Fluid Cryogenics in Mimicking Shutoff Barrier Characteristics
Authors: Al-Otaibi N. , Pinero Zambrano N. , Al-Obaidi I. , Mazzella C.
Published: January 2016

The objective of this paper is to discuss the successful application of a cryogenic freeze plug to fulfill the requirements of dual shutoffs prior to removing the production tree. This operation is presented as a substitute when conventional means are not feasible.

The Saudi Aramco policy regarding the decompletion of wells with downhole packers requires two independent shutoff barriers for the tubing and tubing casing annulus prior to the removal of the production tree. These shutoffs must be independently and simultaneously operated. Moreover, each shutoff must be pressure tested separately. A dual shutoff is easily achievable with conventional means. That is, tubing plugs and tubing hanger back pressure valves, or a combination of the two.

Prior to removing the production tree from an oil-producing well, the production tubing status was found to have collapsed and parted. With the presented conditions, the only annular barrier was the kill fluid column. The well also had leaking tubing hanger seals, which were not holding pressure. As a result, introducing an additional shutoff barrier proved challenging.

An innovative practice was presented as a second shutoff application. The proposal was to utilize the cryogenic freeze plug as a solution to this event. The kill fluid column, filling the tubing and tubing casing annulus, was frozen by a cryogenic freeze plug method. This allowed the fluid to mimic the form of a second barrier.

This application serves as a temporary secondary barrier that would withstand the required pressure test with a full column of kill fluid in the tubing and tubing casing annulus.

This paper reviews the methodology, purpose, technique, and qualification of cryogenic freezing as a second barrier. It also supports the positive trend of technical reviews of new methods or alternative techniques for nonconventional isolation barriers or shutoffs.
Overcoming Open Hole Multistage Acid Fracturing Challenges in Saudi Arabian Carbonate Reservoirs with Swellable Packers, Best Practices and Dynamic Evaluation
Authors: Malik Ataur R. , Leal Jairo A. , Asiri Mohammed A. , Ogundare Tolulope M. , Soriano Eduardo , Vega Roberto , Lopez Alfredo
Published: January 2016

This paper describes the evolution of Open Hole (OH) Multi-Stage Fracture (MSF) completions that have been deployed in the Saudi Arabian tight gas carbonate reservoirs for the past several years. The carbonate reservoir in Saudi Arabia is often highly stressed and heterogeneous and fracturing treatment response can vary significantly between stages across the same reservoir.

This paper also defines the best drilling and deployment practices of OH MSF completion with swellable packers, diagnostic technique of OH packer's integrity, acid fracturing strategies, and well performance of Saudi Arabian carbonate gas reservoirs. It is important to drill in the minimum stress direction so that transverse fractures can be induced. The swellable packers are to be set across good gauged section with optimum spacing between packers and fracture ports. The stimulation treatment designs need to be tailored with optimum fluid volume after evaluating the status of packer integrity between each acid fracturing treatment.

Maintaining OH packer integrity between acid fracturing stages has become the most prevailing concern in emerging independent hydraulic fractures. Evident hydraulic communication between the stages through OH packers can develop a single dominant fracture affecting the well's sustainable gas rate as well as the recovery of final cumulative gas. The loss of annular isolation during fracturing with reactive fluids is often unavoidable in the presence of severe washout and unfavorable location of packers and fracture ports. Drilling in the minimum stress direction, inclusion of swellable packers, scrutinized depth selection of packers and fracture ports, dynamic evaluation of packer integrity between injections, detailed after-closure analysis, and vibrant optimization of acid stimulation treatments have increased effectiveness of acid stimulation and enhanced production.

Even though fracturing treatments in low permeability oil and gas bearing sandstone formations are routinely executed in North America through OH Multi-Stage Fracturing completion to maximize stimulated reservoir volume, but it is not as common completion technique during acid fracturing treatments in the Carbonate gas reservoirs. This paper highlights unique challenges and recommendations for acid fracturing treatments in carbonate reservoirs through OH MSF completion.
Insights Into Mobilization of Shale Oil by Use of Microemulsion
Authors: Bui Khoa , Akkutlu I. Yucel , Zelenev Andrei , Saboowala Hasnain , Gillis John R. , Silas James A.
Published: January 2016

Molecular-dynamics simulation is used to investigate the nature of two-phase (oil/water) flow in organic capillaries. The capillary wall is modeled with graphite to represent kerogen pores in liquid-rich resource shale. We consider that the water carries a nonionic surfactant and a solubilized terpene solvent in the form of a microemulsion, and that it was previously introduced to the capillary during hydraulic-fracturing operation. The water has already displaced a portion of the oil in place mechanically and now occupies the central part of the capillary. The residual oil, on the other hand, stays by the capillary walls as a stagnant film.

Equilibrium simulations show that, under the influence of organic walls, the solvent inside the microemulsion droplets enables not only the surfactant but also the complete droplet to adsorb to the interfaces. Hence, delivering the surfactant molecules to the oil/water interface is achieved faster and more effectively in the organic capillaries. After the droplet arrives at the interface, the droplet breaks down and the solvent dissolves into the oil film and diffuses. This process is similar to drug delivery at nanoscale.

Using nonequilibrium simulations based on the external force-field approach, we numerically performed steady-state flow measurements to establish that the solvent and the surfactant molecules play separate roles that are both essential in mobilizing the oil film. The surfactant deposited at the oil/water interface reduces the surface tension and acts as a linker that diminishes the slip at the interface. Hence, it effectively enables momentum transfer from the mobile water phase to the stagnant oil film. The solvent penetrating the oil film, on the other hand, modifies flow properties of the oil. In addition, as a result of selective adsorption, the solvent displaces the adsorbed oil molecules and transforms that portion of the oil into the free oil phase. Consequently, the fractional flow of oil is additionally increased in the presence of solvent. The results of this work are important for understanding the effect of microemulsion on flow in organic capillaries and its effect on shale-oil recovery.
Proactive Optimization of Intelligent-Well Production Using Stochastic Gradient-Based Algorithms
Authors: Sefat Morteza Haghighat , Muradov Khafiz M. , Elsheikh Ahmed H. , Davies David R.
Published: January 2016

The popularity of intelligent wells (I-wells), which provide layer-by-layer monitoring and control capability of production and injection, is growing. However, the number of available techniques for optimal control of I-wells is limited (Sarma et al. 2006; Alghareeb et al. 2009; Almeida et al. 2010; Grebenkin and Davies 2012). Currently, most of the I-wells that are equipped with interval control valves (ICVs) are operated to enhance the current production and to resolve problems associated with breakthrough of the unfavorable phase. This reactive strategy is unlikely to deliver the long-term optimum production. On the other side, the proactive-control strategy of I-wells, with its ambition to provide the optimum control for the entire well's production life, has the potential to maximize the cumulative oil production. This strategy, however, results in a high-dimensional, nonlinear, and constrained optimization problem.

This study provides guidelines on selecting a suitable proactive optimization approach, by use of state-of-the-art stochastic gradient-approximation algorithms. A suitable optimization approach increases the practicality of proactive optimization for real field models under uncertain operational and subsurface conditions. We evaluate the simultaneous-perturbation stochastic approximation (SPSA) method (Spall 1992) and the ensemble-based optimization (EnOpt) method (Chen et al. 2009). In addition, we present a new derivation of the EnOpt by use of the concept of directional derivatives.

The numerical results show that both SPSA and EnOpt methods can provide a fast solution to a large-scale and multiple I-well proactive optimization problem. A criterion for tuning the algorithms is proposed and the performance of both methods is compared for several test cases. The used methodology for estimating the gradient is shown to affect the application area of each algorithm. SPSA provides a rough estimate of the gradient and performs better in search environments, characterized by several local optima, especially with a large ensemble size. EnOpt was found to provide a smoother estimation of the gradient, resulting in a more-robust algorithm to the choice of the tuning parameters, and a better performance with a small ensemble size. Moreover, the final optimum operation obtained by EnOpt is smoother. Finally, the obtained criteria are used to perform proactive optimization of ICVs in a real field.
A 3D Transient Model for the Multiphase Flow in a Progressing-Cavity Pump
Authors: de Azevedo Victor W. , de Lima João A. , Paladino Emilio E.
Published: January 2016

This paper presents the development of a computational-fluid-dynamics (CFD) model for the 3D transient two-phase flow within a progressing-cavity pump (PCP). The model implementation was only possible because of the meticulous mesh-generation and mesh-motion algorithm, previously published by the authors, which is briefly described herein. In this algorithm, a structured mesh was generated by defining all nodes’ positions and connectivities, for each rotor position by means of FORTRAN subroutines, which were embodied into ANSYS CFX software. The model is capable of predicting accurately the volumetric efficiency and the viscous losses, and it provides detailed information of pressure and velocity fields and void distribution along the pump. Such information could be of fundamental importance for product development and/or optimization for field operation. In field applications, the common situation is that in which the oil comes into the pump accompanied with free gas, which characterizes a multiphase flow. Simplified models on the basis of the calculation of the backflow or “slippage,” which is subtracted from the displaced flow rate, fail to characterize the PCP performance under multiphase conditions because the slip is variable along the pump. In this model, the governing equations were solved with an element-based finite-volume method in a moving mesh. The Eulerian-Eulerian approach, considering the homogeneous model, is used to model the flow of the gas/liquid mixture. The compressibility of the gas is taken into account, which is one of the main shortcomings in positive/constant displacement pumps. The effects of the different gas-volume fractions (GVFs) in pump volumetric efficiency, pressure distribution, power, slippage flow rate, and volumetric flow rate were analyzed, and some new insights are presented about the slippage in PCPs operating in multiphase conditions. The results show that the developed model is capable of reproducing pump dynamic behavior under multiphase-flow conditions performed early in experimental works.
Fabrication and evaluation of an attapulgite membrane as the filter for recycling blowdown water from industrial boilers
Authors: Fan Baomin , Hao Hua , Guo Anru , Yang Ruping
Published: January 2016

Continuous blowdown water (CBW) from industrial boilers is of great quantity and energy, and therefore worth recycling. According to the data from a long period of monitoring, carbonate and sulfate were documented as the main contaminants in CBW. Herein, an attapulgite (ATP) membrane was prepared on a macroporous Al2O3 support through solid state sintering. The prepared membrane (attapulgite membrane (ATM)) was characterized by mercury porosimetry, scanning electron microscope, X-ray diffraction, and permselectivity analysis in dead-end mode. The optimal sintering temperature was 800 °C based on the morphology of the sintered active layer and its adhesive strength with support. The active layer exhibited a pore size distribution concentrated on 12.7nm with a thickness of about 80μm. In addition, crystal structures of ATP were retained in powder form after sintering. ATM obtained a pure water permeability of 1,411.87Lm–2h–1MPa–1 with the effective retention of carbonate and sulfate through electrical-related interactions. Several ATM filters were also developed and mounted on the boiler blowdown pipe, which had a high rejection rate of alkalinity and dissolved solids in CBW. The volume of wastewater emitted from the low-pressure boiler was reduced, since the filtrate could be recycled as part of the make-up water.
A systematic approach for the assessment of bacterial growth-controlling factors linked to biological stability of drinking water in distribution systems
Authors: Prest E. I. , Hammes F. , Kötzsch S. , van Loosdrecht M. C. M. , Vrouwenvelder J. S.
Published: January 2016

A systematic approach is presented for the assessment of (i) bacterial growth-controlling factors in drinking water and (ii) the impact of distribution conditions on the extent of bacterial growth in full-scale distribution systems. The approach combines (i) quantification of changes in autochthonous bacterial cell concentrations in full-scale distribution systems with (ii) laboratory-scale batch bacterial growth potential tests of drinking water samples under defined conditions. The growth potential tests were done by direct incubation of water samples, without modification of the original bacterial flora, and with flow cytometric quantification of bacterial growth. This method was shown to be reproducible (ca. 4% relative standard deviation) and sensitive (detection of bacterial growth down to 5 µg L−1 of added assimilable organic carbon). The principle of step-wise assessment of bacterial growth-controlling factors was demonstrated on bottled water, shown to be primarily carbon limited at 133 (±18) × 103 cells mL−1 and secondarily limited by inorganic nutrients at 5,500 (±1,700) × 103 cells mL−1. Analysis of the effluent of a Dutch full-scale drinking water treatment plant showed (1) bacterial growth inhibition as a result of end-point chlorination, (2) organic carbon limitation at 192 (±72) × 103 cells mL−1 and (3) inorganic nutrient limitation at 375 (±31) × 103 cells mL−1. Significantly lower net bacterial growth was measured in the corresponding full-scale distribution system (176 (±25) × 103 cells mL−1) than in the laboratory-scale growth potential test of the same water (294 (±35) × 103 cells mL−1), highlighting the influence of distribution on bacterial growth. The systematic approach described herein provides quantitative information on the effect of drinking water properties and distribution system conditions on biological stability, which can assist water utilities in decision-making on treatment or distribution system improvements to better control bacterial growth during water distribution.
Novel Trolox derivatives as antioxidant: A DFT investigation
Authors: Farmanzadeh Dvood , Najafi Meysam
Published: January 2016

In this paper the antioxidant activity of Trolox derivatives were
investigated by density function theory and polarization continuum model as
solvent model in order to propose the novel derivatives with higher
antioxidant activity from a theoretical viewpoint. The effects of various
ortho and meta substituents on the reaction enthalpies of antioxidant
mechanisms of Trolox were investigated. Also the effect of reducing the
number of atoms in the heterocyclic ring and effect of replacing the oxygen
heteroatom of Trolox with other heteroatoms on the antioxidant activity of
Trolox were evaluated. Results show that the NH2, OH and NHMe substituents in
meta and ortho positions decrease the BDE and IP values and also increase the
antioxidant activity of Trolox from the theoretical viewpoint. The
derivatives e, c and d with NH, S and Se instead of O have higher antioxidant
activity from the theoretical viewpoint. Obtained results show that reducing
the number of atom in the heterocyclic ring (derivatives a and b) decrease
the BDE and IP values and also increase the antioxidant activity of Trolox
from the theoretical viewpoint. The linear dependencies between BDE of OH
bond and IP values of studied Trolox derivatives and corresponding EHOMO and
R(O-H) values can be useful to propose novel derivatives with higher
antioxidant activity from the theoretical viewpoint.
Thermal analysis of formation of nano-crystalline BaTiO3 using Ba(NO3)2 and TiO2
Authors: Ansaree Jawed , Upadhyay Shail
Published: January 2016

The reaction of Ba(NO3)2 with TiO2 was studied by thermogravimetric (TG) and
differential scanning calorimetric (DSC) techniques up to 1000?C and in
nitrogen atmosphere. It was found that the formation of BaTiO3 takes place
above 600?C and that precursor mixing time and heating rate have no effect
on the reaction temperature. BaTiO3 powder was prepared by calcination of
Ba(NO3)2 and TiO2 precursor mixture at 800?C for 8 h. X-ray diffraction
analysis of the synthesized BaTiO3 confirmed the formation of tetragonal
phase with lattice parameters a = 3.9950?0.0003? and c = 4.0318?0.0004?.
Thermal analysis of the synthesized BaTiO3 powder showed weight loss within
temperature range 40-1000?C of only 0.40%. This small amount of weight loss
was connected with some impurity phase, and identified as BaCO3 using
Fourier transform infrared (FTIR) technique.
Alumina matrix ceramic-nickel composites formed by centrifugal slip casting
Authors: Zygmuntowicz Justyna , Miazga Aleksandra , Konopka Katarzyna , Edrysiak Katarzyna , Kaszuwara Waldemar
Published: January 2016

The paper is focused on the possibility of fabricating the alumina matrix
ceramic-nickel composites with gradient concentration of metal particles.
Centrifugal slip casting method was chosen for the composite fabrication.
This method allows fabrication of the graded distribution of nickel particles
in the hollow cylinder composites. The horizontal rotation axis was applied.
The samples were characterized by XRD, SEM and quantitative description of
the microstructure. The macroscopic as well as SEM observations of the
prepared composites confirmed the gradient concentration of Ni particles in
the composite materials. The application of the centrifugal slip casting
method allows for the graded distribution of metal particles in the samples.
Dielectric studies on cerium doped BaLa2Ti3O10
Authors: Abhange Parshuram , Malvade Vijaykumar , Chandralingam Sonnati , Kokare Shrikant
Published: January 2016

The BaLa2-xCexTi3O10 samples (with x = 0.2, 0.4, 0.6 and 0.8) were prepared
by hydroxide co-precipitation method and finally sintered at 1150?C. The
structure of the prepared samples was characterized by XRD and SEM. The
single phase material was confirmed only for the BaLa1.8Ce0.2Ti3O10
ceramics. However, at higher cerium concentration secondary phase was
observed. The characteristic plate-like structure, having grains with
submicrometer thickness and high aspect ratio, was clearly observed by SEM.
The results of dielectric measurement suggest that the appropriate
adjustment of doping (with x between 0.2 and 0.8) will give sufficient high
dielectric constant at very low loss. The resistivity of samples decreases
with increase in temperature indicating the normal semiconducting electrical
behaviour.
GLP-1 Cleavage Product Reverses Persistent ROS Generation After Transient Hyperglycemia by Disrupting an ROS-Generating Feedback Loop
Authors: Giacco Ferdinando , Du Xueliang , Carratú Anna , Gerfen Gary J. , D’Apolito Maria , Giardino Ida , Rasola Andrea , Marin Oriano , Divakaruni Ajit S. , Murphy Anne N. , Shah Manasi S. , Brownlee Michael
Published: January 2016

The assumption underlying current diabetes treatment is that lowering the level of time-averaged glucose concentrations, measured as HbA1c, prevents microvascular complications. However, 89% of variation in risk of retinopathy, microalbuminuria, or albuminuria is due to elements of glycemia not captured by mean HbA1c values. We show that transient exposure to high glucose activates a multicomponent feedback loop that causes a stable left shift of the glucose concentration-reactive oxygen species (ROS) dose-response curve. Feedback loop disruption by the GLP-1 cleavage product GLP-1(9–36)amide reverses the persistent left shift, thereby normalizing persistent overproduction of ROS and its pathophysiologic consequences. These data suggest that hyperglycemic spikes high enough to activate persistent ROS production during subsequent periods of normal glycemia but too brief to affect the HbA1c value are a major determinant of the 89% of diabetes complications risk not captured by HbA1c. The phenomenon and mechanism described in this study provide a basis for the development of both new biomarkers to complement HbA1c and novel therapeutic agents, including GLP-1(9–36)amide, for the prevention and treatment of diabetes complications.
An Exploration of Canadian Physiotherapists' Decisions about Whether to Supervise Physiotherapy Students: Results from a National Survey
Authors: Hall Mark , Poth Cheryl , Manns Patricia , Beaupre Lauren
Published: January 2016

Purpose: To explore Canadian physiotherapists' perceptions of the factors that influence their decisions whether to supervise students in clinical placements. Methods: Using accepted survey development methodology, a survey was developed and administered to 18,110 physiotherapists to identify which factors contribute to the decision to supervise students. The survey also gave respondents opportunities to provide comments; these were analyzed via directed content analysis, using the factors identified in an exploratory factor analysis as an organizing structure. Results: A representative sample of 3,148 physiotherapists responded to the survey. Qualitative analysis of respondent comments provided a rich understanding of the factors contributing to the decision on whether to supervise students, which centred on themes related to stress, workplace productivity, the evaluation instrument, student preparation, and physiotherapists' professional roles and responsibilities. Challenges specific to loss of income and the ethics of charging for student services in private practice were also identified. Conclusions: Supervising students can be stressful, and stress is perceived by respondents to be most influential in deciding whether to supervise students. Effective supervisor training may mitigate some of the stresses related to supervising students. A collaborative approach involving all stakeholders is needed to resolve the issues of student placement capacity.
Examining the Need for a New Instrument to Evaluate Canadian Physiotherapy Students during Clinical Education Experiences
Authors: Hall Mark , Manns Patricia , Poth Cheryl , Beaupre Lauren
Published: January 2016

Purpose: To gauge the need for a new assessment instrument for Canadian physiotherapy students on clinical placements. Methods: A national survey was developed and distributed to 18,110 Canadian physiotherapists. Results: A total of 3,148 physiotherapists from diverse practice settings responded to the survey. Of those who indicated that student evaluation was applicable to them (n=2,393), 70% stated that a new instrument was needed; of these, 78% felt that the new instrument should be based on Canadian practice standards and rated with an anchored visual analogue scale, and 73% said they would be comfortable completing the instrument online. Conclusion: The majority of physiotherapists surveyed perceive a need for a new clinical evaluation instrument based on Canadian practice standards. A shorter, Canadian-based instrument may help recruit more clinical instructors and build capacity for clinical placements.
Preparing for System Performance Measures and Target-Setting Requirements of the Moving Ahead for Progress in the 21st Century Act
Authors: Eisele William L. , Schrank David L. , Fontaine Michael D.
Published: January 2016

The Moving Ahead for Progress in the 21st Century Act (MAP-21) established performance-based planning and programming requirements to improve transportation decision making and increase the accountability and transparency of federal highway programs. At the time of the writing of this paper, the MAP-21 performance requirements for system performance, congestion mitigation and air quality, and freight had not yet been released, but many transportation agencies had begun efforts to understand and implement performance management activities in anticipation of the MAP-21 system performance requirements. The Virginia Department of Transportation (DOT) has long been a leader in transportation performance activities. Continuing this trend, the Virginia DOT had great interest in evaluating system performance (beginning with the Interstate system) to demonstrate how system-wide measures could be computed and how targets could be set. The Virginia DOT contracted with the Texas A&M Transportation Institute to develop these measures for the Virginia Interstate system as a pilot test. This paper describes the successfully developed and demonstrated methodology for computing a number of mobility, reliability, and congestion magnitude performance measures along with targets for selected measures. Researchers divided the Virginia Interstate roadways into 199 reporting segments. Performance statistics were computed for each segment and aggregated up to the urban area, Virginia DOT district, and statewide level. Major lessons learned from this effort are documented in this paper and should serve to provide additional guidance to other agencies beginning this type of performance measurement effort.
Computing Performance Measures with National Performance Management Research Data Set
Authors: Kaushik Kartik , Sharifi Elham , Young Stanley Ernest
Published: January 2016

The National Performance Management Research Data Set (NPMRDS) was procured by the FHWA Office of Operations in 2013. NPMRDS initially served as a research data set for sponsored programs, but rights to use the data set were secured for state departments of transportation and metropolitan planning organizations in anticipation of the performance measure requirements of the Moving Ahead for Progress in the 21st Century Act. NPMRDS is a form of commercial GPS probe data; that is, the traffic conditions are derived from vehicles that periodically self-report speed, position, and heading with GPS electronics. NPMRDS differs from commercially available data feeds in that FHWA specified that no smoothing, outlier detection, or imputation of traffic data be performed. As a result, NPMRDS contains unique characteristics for statistical distribution of reported travel times. These are characteristics such that traditional processing techniques are ineffective in obtaining accurate performance measures. This paper proposes a method for handling the challenges posed by NPMRDS and computing meaningful performance measures from it. The paper first exposes the challenges in processing NPMRDS data and defines a method for overcoming the challenges. The paper compares the results from the proposed method with traffic data from commercial probe data sources and a reference reidentification data source at two case study locations. The case studies indicate that this paper successfully shows the ability to capture performance measures from NPMRDS more accurately with techniques originally developed to accurately reflect travel time and travel time reliability on interrupted-flow facilities.
Wall and Geotechnical Asset Management Implementation at the Colorado Department of Transportation
Authors: Vessely Mark , Widmann Beth , Walters Bryant , Collins Mike , Funk Natasha , Ortiz Ty , Laipply Joshua
Published: January 2016

The Colorado Department of Transportation (DOT) has successfully initiated risk-based asset management programs for retaining walls, sound walls, and geotechnical assets. This paper reviews the development and status of programs for walls and other assets described as geotechnical hazards by the Colorado DOT. The formulation of these programs was completed in less than a year and led to long-term funding plans that were approved by department consensus. The programs were designed to protect the safety of the traveling public, improve mobility, and reduce maintenance expenditures by identifying deficiencies and evaluating performance improvement through corrective actions. The asset management plans were developed from inventory data compiled from existing department records and geographic information systems. For the retaining and sound wall assets, the data were integrated with the Colorado DOT bridge management and national bridge inventory system databases. The asset management programs corresponded with performance targets of the Moving Ahead for Progress in the 21st Century Act, and the analysis sought to obtain the greatest reduction in risk over the remaining life cycle. Multiple inspection and analysis levels varied the amount of data collected to direct resources toward assets with higher risk. The inventory, inspection, and management of these assets were performed with handheld, web-based data collection applications on mobile devices. The applications collected, geospatially located, analyzed, and organized inspection data and thus increased the efficiency of the tasks. The applications also had risk-based escalation routines and notification processes for critical situations identified by field inspectors.
Approach to Classifying Freight Data Elements across Multiple Data Sources
Authors: Seedah Dan P. K. , Sankaran Bharathwaj , O'Brien William J.
Published: January 2016

Multiple freight data sources, both public and private, are available to practitioners for understanding freight demand and evaluating current and future freight transportation capacity. The challenge of working with multiple data sources is dealing with the syntactic and semantic heterogeneity in these sources. To assist practitioners in addressing this challenge, a unified perspective from which data elements from multiple sources can be examined is proposed. The role-based classification schema (RBCS) organizes and classifies data elements within their respective parent databases such that similar data elements across multiple sources can be grouped. RBCS is based on two levels of classification: a primary group that characterizes data elements according to the type of object that they describe and a secondary group that differentiates between elements that identify objects and those that describe features related to the objects. When similar data elements are ascertained, the subsequent process of resolving syntactic and semantic heterogeneity becomes much clearer, especially with hundreds of data elements. The proposed schema was validated by classifying 1,624 data elements from 28 freight data sources, and it was compared with the existing mnemonic CODMRT, which defined key attributes of freight-related shipments: commodity, origin, destination, mode, route, and time. Examples of applications in the areas of data bridging and multidatabase querying are also presented.
Development of Algorithms to Convert Large Streams of Truck GPS Data into Truck Trips
Authors: Thakur Aayush , Pinjari Abdul Rawoof , Zanjani Akbar Bakhshi , Short Jeffrey , Mysore Vidya , Tabatabaee S. Frank
Published: January 2016

This paper documents the development and validation of the algorithms and procedures used to convert large streams of raw GPS data available from the American Transportation Research Institute into a database of truck trips for use in analysis and modeling of statewide freight truck travel. Also presented are the results from the conversion of 4 months of raw GPS data from Florida, totaling more than 145 million GPS records, into a database of more than 1.2 million truck trips within, into, and out of Florida. The procedures and implementation details described in this paper will be useful to transportation planning agencies in converting raw GPS data streams into more usable truck trip databases for truck flow modeling and analysis at statewide and megaregional levels.
Direkte, indirekte und kombinierte Effekte von Wölfen auf die Waldverjüngung
Authors: Kupferschmid Andrea D. , Bollmann Kurt
Published: January 2016

Direct, indirect and combined effects of wolves on tree regeneration

The wolf currently returns to its traditional distribution area in central Europe. As a large carnivore, he will change the interactions between the organisms there. The impact of wolves on wild ungulates and on the vegetation cover and its composition is manifold: besides direct, numeric effects of wolves on the abundance and demography of their prey populations (like chamois, roe deer and red deer), indirect functional effects through mediated behavior of ungulates are also reported. In a first phase of wolf recolonization with low population density in a region, the functional effects as changes in the spatio-temporal use of habitats and resources are considered to be dominant because the wild ungulates attempt avoiding to become a prey. Later, in phases with higher wolf densities, direct numeric effects on the abundance of prey species should become more obvious. Such interactions among predator and prey species also have an impact on the browsing of tree regeneration. Since the spatio-temporal habitat use of prey species is mediated by the occurrence and abundance of large predators, we cannot assume that the browsing level will gradually decrease in general. Wild ungulates could more often hide or retreat into steep and rocky terrain or towards human settlement. Hence, trophic interactions between predators, herbivores and forests are complex and multilayered, in particular because forest ecosystems in central Europe are strongly influenced by forestry and hunting practices. This limits the trophic cascading impact of carnivores on forest. Our review demonstrates that the equation “wolf = less ungulates = fewer browsing” is not a general rule.
Huftierbestände und Verbissintensitäten nach der Luchswiederansiedlung im Kanton St. Gallen
Authors: Schnyder Jasmin , Ehrbar Rolf , Reimoser Friedrich , Robin Klaus
Published: January 2016

Ungulate populations and browsing intensities following the reintroduction of lynx in the canton of St. Gallen

In the context of the project “Lynx resettlement north-east Switzerland” (LUNO), the Eurasian lynx (Lynx lynx L.) was reintroduced in the canton of St. Gallen from 2001. As a consequence of reduced roe deer (Capreolus capreolus L.) and Alpine chamois (Rupicapra rupicapra L.) population sizes, one goal was the reduction of browsing intensities in young forest stands. This study investigates interactions between the levels of this trophic cascade by means of data on lynx distribution, roe deer and chamois populations (hunting statistics and population estimations) as well as browsing intensities. The results have shown significantly reduced roe deer and chamois population sizes in the years after lynx reintroduction. The effect of lynx could have worked cumulatively with factors like hunting, weather conditions and diseases (chamois). Within the chamois population, the lynx probably affected primarily the forest chamois, although before and after the lynx presence other causal reasons have been responsible for population decreases. Furthermore, there was noted a significantly positive relationship between hunting statistics (as an indicator of local ungulate population sizes) and browsing intensities, although the size of local ungulate populations was one influencing factor among many more. The browsing intensity of silver fir (Abies alba Mill.) was significantly reduced after lynx reintroduction in the core area of lynx distribution. All results have shown significant correlations and suggest an indirect influence of lynx on browsing intensities of silver fir. However, causal connections should be analysed in further studies.
Wirtschaftliche Konsequenzen waldbaulicher Strategien zur Bewältigung des Klimawandels
Authors: Pauli Bernhard , Stöckli Barbara , Rosset Christian
Published: January 2016

Economic consequences of silvicultural strategies for tackling climate change

Climate change poses significant economic challenges for Swiss forest management. The main issue is which silvicultural strategies are best suited to ensuring economic success and minimising loss even under new climatic conditions. As part of the “Forest and Climate Change” programme, a model has been developed to calculate the monetary effects of four silvicultural strategies – a profit-oriented, a risk-reducing, a cost-avoiding and a reference strategy. The results obtained, valid for the Swiss Central Plateau, show that the various silvicultural strategies have a strong influence on economic success. A profit-oriented or a risk-reducing strategy appears to be the most promising economically. “Continue as before” represents the worst strategy. Government and the forestry sector must now initiate appropriate measures.
Desire's Politics: Félix Guattari and the Renewal of the Psychoanalytic Left
Authors: Herzog Dagmar
Published: January 2016

The work of Gilles Deleuze and Félix Guattari is experiencing a considerable revival in the early twenty-first century, among queer, disability, economic justice, and environmental activists, but also among psychoanalysts across a global geographical range. This essay revisits the key coauthored text of Anti-Oedipus (1972) – with its innovative mix of ideas taken from the work of Wilhelm Reich, Melanie Klein, Jacques Lacan, and Frantz Fanon – as well as an array of Guattari's subsequent writings in order to make an argument for Guattari as not just a critic of stultifying existing forms of psychoanalysis but also as a highly creative revitalizer of the psychoanalytic project. This project was, under the impact not least of the sexual revolution, feminism, and gay rights as well as New Left, anticolonial, and antiwar activism, undergoing substantial transformation as the locus of intensive productivity was shifting from the US to Western Europe and Latin America.
A Soldier in the Psychoanalytic Army: Claud Daly's ‘Defence of the Garrison’
Authors: Singh Akshi
Published: January 2016

This article discusses the published psychoanalytical writing and unpublished diaries of Claud Dangar Daly. An officer in the colonial army, Daly was posted in India and served in the First World War, which is when he was introduced to psychoanalysis through shell-shock treatment with Ernest Jones. He went on to have two further analyses with Freud, and one with Ferenczi. Daly's diaries are records of his dreams and his interpretations of them, written while Daly was posted in the North Western Frontier of British India. The article explores Daly's relationship to psychoanalysis, politics and his accounts of sexuality through his published and unpublished writings, and uses this to reflect on Freud's insights on groups, civilization and ethics.
Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions
Authors: Takahashi Yusuke , Nakasato Reo , Oshima Nobuyuki
Published: January 2016

A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD) of the European Space Agency (ESA) in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.
Novel QTL for Stripe Rust Resistance on Chromosomes 4A and 6B in Soft White Winter Wheat Cultivars
Authors: Klarquist Emily , Chen Xianming , Carter Arron
Published: January 2016

Stripe rust (caused by Puccinia striiformis f. sp. tritici) of wheat (Triticum aestivum) is a devastating disease in temperate regions when susceptible varieties are grown and environmental conditions sustain high disease pressures. With frequent and severe outbreaks, disease resistance is a key tool for controlling stripe rust on wheat. The goal of this research was to identify quantitative trait loci (QTL) involved in stripe rust resistance from the important US Pacific Northwest soft white winter wheat varieties “Eltan” and “Finch”. An F2:5 recombinant inbred line (RIL) mapping population of 151 individuals derived from the Finch × Eltan cross was developed through single seed descent. A linkage map comprising 683 unique single nucleotide polymorphism (SNP) loci and 70 SSR markers were used to develop 22 linkage groups consisting of 16 of the 21 chromosomes. Stripe rust data were collected on the RILs during the summers of 2012 to 2014. QTL analysis identified two genomic regions on chromosomes 4A (QYrel.wak-4A) and 6B (QYrfi.wak-6B) associated with resistance from Eltan and Finch, respectively. The results of the QTL analysis showed that QYrel.wak-4A and QYrfi.wak-6B reduced infection type and disease severity. Based upon both molecular and phenotypic differences, QYrel.wak-4A is a novel QTL for adult plant resistance (APR) to stripe rust.