bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Study on the Photocyclization Mechanism of Diarylethenes with Transition-Metal Substituents
Authors: Hatakeyama Makoto , Yokojima Satoshi , Shinoda Keiko , Koike Takashi , Akita Munetaka , Nakamura Shinichiro 
Published: June 2012

Abstract
Photocyclization mechanism through 3ππ* excited states of metal-containing diarylethene (DAE) ([Fe(Cp)(CO)2]2–DAE (1) and [Fe(Cp)(CO)(PPh3)]2–DAE (2)) is analyzed by using time-dependent density functional theory, to elucidate why the ratio of the open- and closed-ring isomer at the photostationary state depends on the metal-coordinated ligands. Since the 1CT excited states exist at low energy level, the direct 1ππ* cyclization is difficult for the two DAEs. Therefore, the cyclization through triplet states is examined. At the Franck–Condon state for the open-ring isomer of DAEs, the 3CT excited states are the lowest lying triplet excited states instead of the 3ππ* excited states. Therefore, the potential energy curves of the ground and excited states of 1 and 2 are obtained along their cyclization path. The singlet excited states of 1 and 2 are quite similar. In contrast, the potential crossings between 3ππ* and 3CT excited states along the cyclization path make a difference for the two DAEs. In addition, we found that the spin–orbit coupling in the open-ring isomer of 1 is much larger than those in that of 2. The experimental result is thus explained by the triplet cyclization mechanism based on the potential energy curves as well as the spin–orbit couplings.
The Gate "Illyes": Visual essay of a community art project in Hungary
Authors: Ráthonyi Dr. Kinga 
Published: June 2012

Over the past fifteen years the authors have been working together, creating and promoting community art projects. The main objective of these works has always been to shape the users visual environment, with maximum involvement of the local community. Participation in the projects
has allowed people to share creative thoughts, production, ideas, and communicate. These have taken place on site in a communal environment which respects and appreciates the individual. People are free to work/talk/look or just be there. The following visual essay documents a recently completed
project.
Further documentation can be found at the facebook page: "az illyes kapuja"
Measurement of the polarization state of light using an integrated plasmonic polarimeter
Authors: Afshinmanesh Farzaneh , White Justin S. , Cai Wenshan , Brongersma Mark L. 
Published: June 2012

AbstractPlasmonics has started to facilitate the replacement of bulky optical components in optical systems by compact nanometallic elements that perform the same function. This allows for a natural and very dense integration with electronic devices. In this vein, we present a silicon (Si) photodetector integrated with a set of plasmonic structures that can be used as either a broadband linear-Stokes polarimeter or a narrowband full-Stokes polarimeter capable of determining the complete state of polarization of a light beam. At a probe-wavelength of 830 nm, our experimental results show contrast ratios of 25 and 1.13 for orthogonal linear and circular states of polarization, in good agreement with simulations. The resulting device is lightweight, orders of magnitude smaller than conventional polarimeters, and mechanically robust. For these reasons, there promises to be a wide range of applications including polarimetric imaging and sensing.
Mehrpunktmessungen der Schallschnelle mittels neuartigem Lasermessverfahren
Authors: Haufe Daniel , Schlüßler Raimund , Fischer Andreas , Büttner Lars , Czarske Jürgen 
Published: June 2012

Zusammenfassung
Zur Fluglärmreduzierung muss die Interaktion komplexer Strömungs- und Schallphänomene in Triebwerksschalldämpfern analysiert werden. Hierfür wird erstmals ein Doppler-Global-Velozimeter mit Laserfrequenzmodulation eingesetzt und eine Mehrpunktmessung der Schallschnelle in einem Kundtschen Staubrohr demonstriert. Im Ergebnis wurden Schnelleamplituden im Hörbereich aufgelöst, die Messunsicherheit betrug minimal 3 mm/s bei einer Messdauer von 1 s. Die Messtechnik bietet somit hohes Potential bei der Analyse und Optimierung von Triebwerkschalldämpfern.
Interfacility Transfers of Noncritically Ill Children to Academic Pediatric Emergency Departments
Authors: Li Joyce , Monuteaux Michael C. , Bachur Richard G. 
Published: June 2012

OBJECTIVES:We aimed to characterize the demographics, diagnoses, and management of transferred patients who were directly discharged from the emergency department (ED) or admitted less than 24 hours.METHODS:We conducted a retrospective, cross-sectional study of patients classified as interfacility ED transfers over a 12-month period in the Pediatric Health Information System database, an administrative database of 42 tertiary care pediatric US hospitals. The primary study outcomes were ED resource utilization at the receiving facility with a focus on children who were discharged directly from the ED or admitted less than 24 hours.RESULTS:Overall, 24 905 interfacility transfers were identified, accounting for 1.3% of the ED volume of these academic pediatric centers. Of these, 24.7% were discharged directly from the ED and 17.0% were admitted for less than 24 hours. Among those directly discharged from the ED, the 3 most common complaints were orthopedic problems, nonsurgical abdominal pain, and viral gastroenteritis; 20.7% received no medical or procedural intervention. Among those admitted for less than 24 hours, the 3 most common complaints were orthopedic problems, traumatic head injury, and gastrointestinal conditions.CONCLUSIONS:A significant proportion of interfacility transfers to academic pediatric EDs is discharged directly from the ED or is admitted for less than a day. These patients and their clinical outcomes provide insight into the educational needs and medical capabilities of referring hospitals and clinicians.
Teachers Bullied by Students: Forms of Bullying and Perpetrator Characteristics
Authors: Kauppi Teemu , Pörhölä Maili 
Published: June 2012

The focus of this study is on the forms in which the bullying of school teachers by students manifests itself, the characteristics of the students who engage in the bullying, and the manner in which the students who engage in bullying behave in their own peer relationships. The data was gathered from primary and lower secondary school teachers by means of an Internet survey. The answers of 70 teachers who had experienced bullying by their students are examined.The teachers had been exposed to different forms of bullying by students. They had typically been bullied by male students. In most cases, the bullying had been perpetrated by an individual student or a small group of students. According to the teachers’ assessment, the majority of the students who bullied them also bullied their fellow students.
Parametric Study of Fracture Treatment Parameters for UltraTight Gas Reservoirs
Authors: Abaa Kelvin , Wang John Yilin , Ityokumbul Mku Thaddeus 
Published: June 2012

Abstract
Tight gas reservoirs are expected to contribute significantly to the gas and energy supply all over the world. However, the productivity of tight gas wells, especially in the ultra-tight formations, is often lower than expected. One of the needed improvements in reservoir stimulation technology is in the advancement of fracturing fluids and techniques that can help create long and highly conductive fractures and reduce phase trapping at the face of the fracture. Introduction of aqueous based fluids in ultralow permeability sands during hydraulic fracturing decreases the effective gas permeability and ultimate gas recovery. Unfortunately most fracture fluids currently deployed are aqueous based owing to their ease of preparation and low cost. This paper aims to investigate the effect of different fracture fluid systems and fracture treatment parameters and then determine one that achieves a balance of minimal fluid retention, optimal fracture geometry and low cost for ultra-tight gas reservoirs.
In this paper, a dataset of reservoir properties, petrophysical properties, and fracture treatment parameters has been developed based on a complete review of published geological and engineering data of ultra-tight gas reservoir. Then based on numerical parametric studies, the effect of pertinent design factors on hydraulic fracture propagation and geometry is quantified with a fracture simulator. The factors investigated include volumetric injection rate, gel loading and proppant size. Parametric variation of seven different injection rates, seven different fracture fluids, and three different proppants was studied.
A final fracture treatment that achieves maximum fracture length, fracture width and proppant conductivity is determined to be optimal. Results from simulations show that optimal fracture geometry and fracture conductivity based on pumping limitations is obtained at an injection rate of 100 bpm, a gel loading of 50 pptg of linear gel and a proppant size of 20/40 mesh sand.
This paper brings new understanding of fracture behavior in ultra-tight gas reservoirs and serves as a guide for improved hydraulic fracturing practices in ultra-tight gas basins throughout the United States.
Lowering Tubing in Jonah Field Offset Production Decline
Authors: Ogugbue Chinenye E. , Hopkins Cody R. , Greenly Leah R. , Wilson Robert K. , Gates Gordon E. 
Published: June 2012

Abstract
Declining reservoir pressure and rate in the Jonah field has led to the common problem of liquid loading. As fluids accumulate the downhole pressure increases which decreases the available drawdown that allows fluids to flow into a wellbore. Jonah wells are completed in the 2000 - 3500-ft thick Lance Formation, using 8-16 hydraulic fracturing stages. With initial end of tubing (EOT) depths set above the top perforation for most wells, this left approximately 1500-3000 feet (gross pay) of perforations below the EOT. With lifting velocities significantly greater in larger diameter casing than tubing, a liquid column was developing below the EOT and engineering and operational attention was needed to improve field performance.
Improving on the operational efficiency involved the implementation of recommended actions from a cross-functional well by well review group that received input and support from all Jonah asset members. The approach focused on how to improve liquid removal and optimize gas production from wells identified as liquid-loaded. In addition to installing plunger lift systems and injecting soaps, in 2008 a program was started to lower production tubing in wells by approximately 50-70% into perforations; the purpose was to reduce the column of fluid in the wellbore by helping more efficiently unload fluids using the reduced critical flow rate in the tubing and allowing plungers deeper access to the column of liquid covering the perforated interval.
This paper discusses the results of lowering the EOT of over 100 gas producing wells in the Jonah field. The wells showed an average sustained uplift of approximately 105 mcfd, with undiscounted payout of less than 12 months. In addition, on wells that have had the tubing lowered, their decline curves appear to flatten out, offsetting anticipated double digit decline. Practical methods of selecting candidate wells and the new EOT are presented and discussed.
Wellbore Real-time Monitoring and Analysis for Shale Reservoirs
Authors: Gonzalez Luis E. , Chokshi Rajan N. 
Published: June 2012

Abstract
Advances in directional drilling and reservoir stimulation techniques have dramatically increased gas production from wells drilled in shale reservoirs that were considered uneconomical not too long ago. In spite of many advances made on understanding the production behavior of this type of reservoirs, there are many unknowns that still do not have a proper answer. Particularly, it is difficult to predict productivity from cores, logs or DSTs or from early well production performance. Drainage volumes are uncertain and well spacing is based on trial and error methods.
The use of micro-seismic and production logs has helped in the fracture evaluation to determine the drainage volume and fracture inflow. Micro-seismic can provide useful information on the development of fracture symmetry, half-length, azimuth, width and height, and their dependence on the stimulation treatment parameters and reservoir characteristics. Additionally, these fracture geometries in conjunction with other measured or calculated parameters (rates, inflow models) can be used to better understand fracture modeling and production characteristics.
Reviews of production logs have indicated that only a percentage of the fractures are contributing to the production, however considering that this is a transient system, a snapshot measurement is not enough to understand the behavior of the fractures and their contribution over time. It is necessary to have continuous or permanent information from within the wellbore to establish which fractures are contributing and how much.
The near-wellbore temperature distribution yielded by distributed temperature sensing (DTS) or multi-point or array temperature sensing (ATS) can be used to determine the relative amount of fluids that each perforation interval contributes. If this information is combined with one or more pressure measurements and a real-time surface multiphase flow measurement in conjunction with an inflow model for each fractured interval, a production allocation could be calculated for each fracture. This approach is analogous to a traditional well allocation where a daily aggregated measurement at the production plant is back allocated to each well based on wellhead measurements like pressure, temperature and well performance. This paper will provide details on the above mentioned analogy and the use of these technologies to analyze the fracture behavior in horizontal wells in shale reservoirs.
Relating Fracture Network Characteristics to Shale Gas Reserve Estimation
Authors: Akbarnejad-Nesheli Babak , Valkó Peter P. , Lee W. John 
Published: June 2012

Abstract
The Stretched Exponential production Decline Model (SEDM) provides a flexible framework for forcasting production and estimating reserves in unconventional reservoirs. In the following we use the Discrete Fracture Network (DFN) concept to interpret the SEDM results obtained previously. Our study proposes that the SEDM exponent parameter, n can be related to the scale independent characteristics of the created fracture network that in turn can be considered non-varying in a given field (or larger group of wells in the same geological settings and of similar completion type.) Our hypothesis is supported by dry gas flow simulation involving stochastic generation of DFN with various characteristics. The effect of variations in natural fracture lengths, apertures, density, and connectivity are considered along with induced hydraulic fracture dimensions. In view of our findings we present another conditioning approach to robust decline curve analysis and provide application examples for selected Barnett Shale wells.
Optimizing Fracture Spacing to Induce Complex Fractures in a Hydraulically Fractured Horizontal Wellbore
Authors: Jo Hyunil 
Published: June 2012

Abstract
As conventional hydrocarbon reservoirs are depleted and new sources sought for economic and security reasons, unconventional reservoirs attract the oil and gas industry's attention. Among the unconventional options, shale gas reservoirs have become prominent. After many years of working to effectively recover hydrocarbons from the shale gas reservoirs, it has been accepted that creating complex fracture networks by hydraulic fracturing is one of the most efficient ways to produce gas from these reservoirs. Although several factors affect development of the complex fracture networks, the in-situ stress anisotropy (i.e. the maximum in-situ horizontal stress – the minimum in-situ horizontal stress) is the most significant factor. Low in-situ stress anisotropy increases the chance of creating complex fracture networks with hydraulic fracturing. In order to compensate for the in-situ stress anisotropy, M.Y. Soliman suggested arranging a sequence of fracturing stages to make use of the induced stress caused by the net fracturing pressure (Soliman et al. 2008; East et al. 2011). This method is so called Texas Two Step method (TTSM). This research analyzes the effectiveness of TTSM by utilizing the boundary element method (BEM). In addition, the research analyzes and models fracture geometries caused by interaction among multiple hydraulic fractures to determine the optimal fracture spacing for multistage fracturing operations. From the results, this research concludes that curved fractures can enhance or vitiate the stress contrasts induced by the net fracturing pressure, depending on the shape of the curved fractures. It further calculates optimal fracture spacing for operations using the Texas Two Step method.
Comparison of Production Results from Open Hole and Cemented Multistage Completions in the Marcellus Shale
Authors: Snyder Daniel , Seale Rocky 
Published: June 2012

Abstract
With estimates of recoverable reserves at approximately 500 Tcf, the Marcellus Shale has become one of the main unconventional shale targets in the U.S. The Marcellus is part of the Appalachian Basin and underlies 95,000 sq. miles of Pennsylvania, New York, Ohio, Maryland, and West Virginia. The Marcellus is a challenging target due to formation characteristics, making it cost-intensive to develop. In addition, operators working in the Marcellus have had to contend with public opposition to hydraulic fracturing, prompting them to look for technologies to make this process more efficient and less resource intensive.
This paper compares open hole multistage fracturing systems (OHMS) and cemented casing, "plug and perf" (CCPP) completions and presents the evolution of completion methods utilized in the Marcellus Shale. Production results from horizontal wells in two counties completed with OHMS are compared to offset wells completed with the CCPP method. System details, the fracture methods used, as well as the operational efficiencies of OHMS compared to other horizontal completions methods are discussed. In addition, an update on the recent advances in technologies that have been made since the introduction of OHMS to the Marcellus Shale is presented.
Higher cumulative production results at six, 12, and 24 months in both geographic areas of analysis demonstrate the successful application of OHMS systems in the Marcellus Shale. Comparing the two completion methods also highlights the increased efficiency of OHMS systems compared to CCPP. With decreased time and cost requirements, OHMS completions are the clear choice in the Marcellus Shale. Therefore, this paper demonstrates that OHMS technology provides a long-term solution for the life of wells in shale plays. Although the focus is on the Marcellus Shale, principles from this paper can be applied to any unconventional shale reservoir.
The Importance of Slow Slip on Faults During Hydraulic Fracturing Stimulation of Shale Gas Reservoirs
Authors: Zoback Mark D. , Kohli Arjun , Das Indrajit , McClure Mark 
Published: June 2012

Abstract
We utilize several lines of evidence to argue that slow slip on pre-existing fractures and faults is an important deformation mechanism contributing to the effectiveness of slick-water hydraulic fracturing for stimulating production in extremely low permeability shale gas reservoirs. First, we carried out rate and state friction experiments in the laboratory using shale samples from three different formations with a large range of clay content. These experiements indicated that slip on faults in shales comprised of less than about 30% clay is expected to propagate unstably, thus generating conventional microseismic events. In contrast, in formations containing more than about 30% clay are expected to slip slowly. Second, we illustrate through modeling that slip induced by high fluid pressure on faults that are poorly oriented for slip in the current stress field is expected to be slow, principally because slip cannot occur faster than fluid pressure propagates along the fault plane. Because slow fault slip does not generate high frequency seismic waves, conventional microseismic monitoring does not routinely detect what appears to be a critical process during stimulation. Thus, microseismic events are expected to give only a generalized picture of where pressurization is occurring in a shale gas reservoir during stimulation which helps explain why microseismicity does not appear to correlate with relative productivity. We review observations of long-period-long-duration seismic events that appear to be generated by slow slip on mis-oriented fault planes during stimulation of the Barnett shale. Prediction of how pre-existing faults and fractures shear in response to hydraulic stimulation can help optimize field operations and improve recovery.
Shale Gas Drilling Experience and Lessons Learned from Eagle Ford
Authors: Guo Quanxin , Ji Lujun , Rajabov Vusal , Friedheim James , Portella Christin , Wu Rhonna 
Published: June 2012

Abstract
As an industry, we are still in the early stages of the learning curve for shale gas drilling although many shale gas wells have been drilled in recent years. Data from over one thousand wells drilled in the Maverick basin since 2003 were retrieved from an internal drilling database. Among them are over two hundred horizontal wells from the Eagle Ford shale play drilled by 31 different operators between 2008 and early 2011. The analyses of drilling performance data of these horizontal wells offer the establishment of general practice guidelines and recognition of opportunities for improvement in Eagle Ford shale drilling.
Oil-based drilling fluid, or "mud" (OBM) is a typical drilling fluid type currently used to drill from the surface casing shoe to the total depth (TD) in the Eagle Ford shale play. However, water-based mud (WBM) has also been used since the development of the Eagle Ford shale play. A comparative analysis was performed between oil-based and water-based drilling fluids to assess their performances and to identify the key challenges and potential areas for improvement when drilling in the Eagle Ford shale. The analyses included mud chemistry, drilling performance, mud weight and well architectures such as bit sizes, casing sizes and depths of the casing shoe, as well as lateral length. A statistical analysis (P10, P50, and P90) was also performed to evaluate industry-wide drilling performance such as drilling days for wells of various depths. Comparisons were made among different drilling fluid types and different operating companies.
The statistical analysis shows that although overall performance of water-based drilling fluids lags behind that of oil-base fluids in Eagle Ford shale drilling, a certain WBM system shows promising performance close to that of oil-based drilling fluids. The analysis shows that there is a general trend of decreased drilling days per footage over time and a large variation in total drilling days for similar well depths and trajectories. This indicates that although the drilling industry as a whole has improved drilling in the Eagle Ford shale over the years, there is still a large opportunity for improvement. One interesting finding is that some operators can drill wells in fewer days than the industry average even though their drilling fluid cost is slightly more expensive than the industry average. As a result of reduced drilling time, their overall drilling costs are reduced.
Lab test results with different fluid types show that the failure mechanism and shale-fluid interaction of the Eagle Ford shale is different from dispersion or swelling which are typical of traditional shales. The analyses and results of this study on drilling performance data provide lessons learned and general guidelines for current drilling practices and opportunities for improvement such as drilling fluid selections, mud weight, and well architectures in the Eagle Ford shale play.