bluuebunny/crossref_metadata_2025_split huggingface dataset:
AMMONO method of BN, AlN and GaN synthesis and crystal growth.
Authors: Dwili˜ski R. , Doradzi˜ski R. , Garczy˜ski J. , Sierzputowski L. , Palczewska M. , Wysmolek Andrzej , Kami˜ska M. 
Published: August 2016

Microcrystals of BN, AlN and GaN were obtained by the AMMONO method, in which nitridization of metal occurs in supercritical ammonia, at relatively low temperature and pressure conditions (below 550°C and 5 kbar). The reaction rate was regulated by the amount of mineralizers, i.e. alkali metal amides.All crystals obtained by AMMONO method revealed intense and homogenous luminescence. Significant improvement of the optical properties was observed for crystals grown in the presence of Rare Earth elements. For such GaN crystals, helium temperature photoluminescence spectra were dominated by near-band-gap recombination. Exciton lines were extremely narrow, with full-width half-maximum (FWHM) as low as 1 meV. The concentration of uncompensated shallow donors in AMMONO GaN determined by electron paramagnetic resonance measurements was below 5×1015 cm−3.
Crystal Morphology and Optical Emissions of GaN layers grown on Si(111) substrates by Molecular Beam Epitaxy
Authors: Sánchez-García M. A. , Sánchez F. J. , Naranjo F. B. , Calle F. , Calleja E. , Muñoz E. , Jahn U. , Ploog K. H. 
Published: August 2016

Crystal morphology of GaN layers grown on Si(111) evolves from whisker-like microcrystals to compact films as a function of the III/V ratio. Small changes in the III/V ratio (from Ga-rich to N-rich) during the growth of a compact layer result in the appearance of microcrystals on the top of the layer, indicating a sharp transition between the two growth regimes.Four different morphologies are obtained by increasing the III/V ratio: a) completely columnar whisker-like samples exhibiting a pair of intense excitonic emissions at 3.471−3.478 eV; b) a mixture of compact regions with columnar microcrystals showing two pairs of excitonic emissionsnbsp c) compact layers with very small microcrystals on the top surface with a weaker dominant transition at 3.415 eV (±5meV) and, d) full compact and smooth layers with a single dominant excitonic emission at 3.466 eV. A combination of PL measurements with SEM photographs and CL imaging reveals that both pairs of emissions in samples b) come from the columnar microcrystals. The high energy pair (3.471−3.478eV) is attributed to the free-exciton A and a donor-bound exciton while the low energy pair (3.452−3.458eV) is assigned to acceptor-bound excitons associated to valence bands Γ9v and Γ7uv. Power and temperature dependence together with time-resolved data show that the dominant peak at 3.415eV (± 5meV) present in samples c) correspond to a donor-acceptor transition. CL measurements as a function of electron beam energy (depth) also indicate that this emission is more intense towards the interface between the layer and the sample. Finally, the excitonic emission in samples d) is shifted to lower energies due to residual biaxial tensile strain of thermal origin.
AlGaN-Based Bragg Reflectors
Authors: Ambacher O. , Arzberger M. , Brunner D. , Angerer H. , Freudenberg F. , Esser N. , Wethkamp T. , Wilmers K. , Richter W. , Stutzmann M. 
Published: August 2016

We have studied the dependence of the absorption edge and the refractive index of wurtzite AlxGa1−xN films on composition using transmission, ellipsometry and photothermal deflection spectroscopy. The Al molar fraction of the AlxGa1−xN films grown by plasma-induced molecular beam epitaxy was varied through the entire range of composition (0 ≤ x ≤ 1). We determined the absorption edges of AlxGa1−xN films and a bowing parameter of 1.3 ± 0.2 eV. The refractive index below the bandgap was deduced from the interference fringes, the dielectric function between 2.5 and 25 eV from ellipsometry measurements. The measured absorption coefficients and refractive indices were used to calculate the design and reflectivity of AlGaN-based Bragg reflectors working in the blue and near-ultraviolet spectral region.
Fabrication of GaN mesa structures
Authors: Vassilevski K.V. , Rastegaeva M.G. , Babanin A.I. , Nikitina I.P. , Dmitriev V.A. 
Published: August 2016

We report on nickel based technology for the fabrication of GaN mesa structures. Ti/Ni ohmic contacts for n-doped GaN with contact resistivity Rc ~2×10−5 Ω×cm2 and Ni ohmic contacts for p-doped GaN with Rc ~ 4×10−2 Ω×cm2 were formed. Both types of contacts were used as masks for GaN reactive ion etching (RIE) in a CCl2F2/Ar gas mixture. Maximum etch rates of ~ 40 nm/min were obtained. Mesa structures up to 3 μm in height were formed.
Locking compression plate in humeral shaft nonunion: a retrospective study of 18 cases
Authors: Govindasamy Rajesh , Gnanasundaram Ramkumar , Kasirajan Saravanan , Thonikadavath Fawas , Rajadurai Jeff Walter 
Published: August 2016

<p class="abstract"><strong>Background:</strong> Humeral shaft nonunions are frequently seen in Orthopaedic practice. Osteosynthesis with bone grafting is the treatment of choice. Locking compression plate (LCP) is the latest implant used in treating them. We retrospectively evaluated the outcome of use of LCP in humeral shaft non-union resulted by both conservative management and following failed internal fixations.</p><p class="abstract"><strong>Methods:</strong> Eighteen patients with nonunion of humeral shaft in which ten were treated by traditional bone setters and eight followed by failed internal fixation were included in these study. The mean duration of nonunion was 18.3 months (range 8-22). The mean follow up period was 18 months (range 12-26). The mean age of patients was 44.4 years (range 22-60). All patients underwent osteosynthesis with LCP and autologoous cortico-cancellous iliac crest graft. The outcome measures include radiographic assessment of fracture union and preoperative and postoperative function using modified constant and murley scoring system.<strong></strong></p><p class="abstract"><strong>Results:</strong> All fractures united following osteosyntesis average time for union was15 weeks (range 10-24). We did not have any delayed union or non-union. The complications were superficial infection (n=1) and wound haematoma (n=1).Three patients with preoperative radial nerve palsy recovered at the end of four months. Functional evaluation using constant-murley score showed excellent result in 14, good in 3 and fair in 1. We did not have any poor results.</p><strong>Conclusions:</strong> LCP with cancellous bone grafting is a safe reliable option for all forms of humeral shaft nonunion. We recommend it.
Maximizing Drilling Performance with Real-Time Drilling Vibration Mitigation in the Deep Wells
Authors: Cui M. , Wang G. H. , Ge H. Y. , Chen X. Z. , Guo H. W. 
Published: August 2016

Abstract
The present Tarim Basin of China presents drilling chanllenges moving toward deeper hydrocarbon reservoirs, which includes more complex formation, poor bit cutting efficiency and wellbore integrity. The paper introduces the development and application of optimizer of drilling operating parameters named as Smart Driller Indicator (SDI) which worked to deliver continuous improvement in axial vibration and stick-slip mitigation for the presented field.
SDI is based on a soft-closed-loop solution called NAVO real-time vibration monitoring and calculating the optimal drilling parameters for that formation by maintaining an optimum relationship between ROP and energy input. From the perspectives of rock mechanics and conservation of energy, the ideal performance in the optimum proportion among drilling parameters, ROP and MSE have been derived from comprehensive analysis of optimized drilling mechanism. An advanced damped forced torsional vibrarion model in frenquency-domain was developed. Field validation for real-time estimates produced by the model was conducted by a drilling mechanics module sub.
In drlling process, if the ROP is not as good as expected, SDI will automatically evaluates the new hole conditions including the mechanical properties of the formation, bit wear condition and vibration etc, and updates the optimum drilling parameters. The drillers just adjust drilling parameters to follow them, a higher ROP (rate of penetration) and a longer bit run can be achieved. SDI has been applied for more than 20 wells with total footage of over 30,000ft and has shown about 20%-54% ROP improvement and longer bit life compared with conventional driller's drilling habits and totally 125 days and about 1 million dollars have been saved.
As an effective tool for further excavating the potential of ROP, SDI might achieve satisfactory outcomes that overcome the drilling challenges of carbonate formation, gravel and igneous in deep wells.
Improving Operational Cost with SAP
Authors: Taylor Joseph A. 
Published: August 2016

Abstract
For decades, the E&P industry has generated vast quantities of data derived from exploration, development, production and operations. However, very few E&P companies have leveraged the many terabytes of data they generate every day to drive their businesses forward, much less empower themselves with insights-driven decision-making.
In August 2014, the price of a barrel of oil on the global market reached a price of $108.88 (see Figure 1). Although cost plays an important part in determining profits, it wasn't as much of a focus at that point in time. Let's be honest: At that price, the number of assets that could be labeled profitable was on the high side. As a result, the larger E&P companies started to make major capital investments, while a larger number of smaller E&P companies started to appear. This price attracted a lot of attention, prompting E&P companies in the US to make big investments in Shale Plays. Canada increased its investments in Oil Sands. And the US, the world's largest consumer of oil, started making mandates on MPG for vehicles. SCADA systems were the kings of data collection and Production Optimization & Maintenance & Reliability became household phrases. The thought was that even a low producing well could be profitable. In Feb 2016, less than 18 months later, the price of oil plummeted to a low of $33.62 per barrel.
Prescriptive-Based Decision Support System for Online Real-Time Electrical Submersible Pump Operations Management
Authors: Adesanwo Moradeyo , Denney Tommy , Lazarus Sony , Bello Oladele 
Published: August 2016

Abstract
Economic development and operations of new discoveries in frontier environments require advancements in production enhancement technologies, which take advantage of existing infrastructures and reduce overall operating expenses. These production enhancement technologies such as downhole pumping and gas lift (artificial lift technologies); injection of diluents, foamers and chemicals; water and/or fluid injection; often represent the only viable option to enhance well productivity, maximize production and improve recovery of hydrocarbon resources.
Electrical submersible pump (ESP) systems are becoming the fastest growing form of artificial lift pumping technology, with more than 25% of the wells worldwide deploying ESP to surface their hydrocarbons and with more ESP systems being deployed to harsh and remote environments. With the rapid growth of ESP technologies, an appropriate prescriptive-based decision support system is needed to prevent or avoid critical system failures by analyzing the large amount of (observations, algorithms and calculated) information for extending run-time, increasing production and keeping well operation safe. The majority of the existing solutions provide real time data trending, alarming, ESP analysis and diagnostics.
In this work, an efficient and reliable automated system is proposed for change point and anomaly detection, event or fault diagnosis and decision support in ESP operations. Our workflow consists of a quantitative method which combines streaming sensor data, data-rich detection and diagnosis model, fuzzy rule-based expert system and an influence diagram technique to perform prescriptive analysis and provide online real-time recommended action and/or corrective measures concerning the optimal alternative actions to be executed during undesirable ESP incidents or events. System features include a real-time data acquisition device, a real-time modeling engine, a real-time model calibration engine, fault detector program and a fuzzy logic rule-based system that uses an influence diagram technique to advice on ESP operating conditions. The proposed procedure is tested in multiple fields to verify the functionalities of the system. The results show that the proposed methodology can be efficiently used in practice. The methodology was used in several case studies and produced superior results in comparison to conventional methods.
Automatic Performance Analysis and Estimation of Risk Level Embedded in Drilling Operation Plans
Authors: Cayeux Eric , Daireaux Benoît , Karimi Balov Mohsen , Haavardstein Stein , Magne Stokland Leif , Saasen Arild 
Published: August 2016

Abstract
It is not unusual that the difficulties encountered during a drilling operation can be tracked down to choices made during the planning stage. However, generating a robust drilling operation plan is not easy as there are often substantial uncertainties associated with the actual geological context. To address this problem, a method is proposed that evaluates quantitatively the risk levels of a drilling operational plan as a function of the underlying uncertainty associated with its description.
To achieve that goal, the first task is to describe precisely the sources of uncertainties. The limits by which a drilling operation shall conform may be uncertain therefore defining fuzzy risk boundaries. The actual well construction may deviate from the plan, either because of unavoidable uncertainties in measurements as with the actual wellbore position, or because adjustments will be made during the operation such as changes in mud weight and rheology. Finally, the actual possible drilling performance may be subject to unforeseen geological variations and unprecise formation rock strength characteristics.
Equipped with this probabilistic environment, we can perform drilling optimization in two successive steps. First, the uncertainty is propagated into drilling simulations, and risks associated to pressure control, cuttings transport, and drillstring stability are evaluated. Second, parameter optimization within the allowed window, can provide a strategy to obtain the best performance possible with respects to acceptable risk levels. As a result, both quantitative risk analysis and drilling optimization under several constraints are available to the drilling engineer as a decision support tool for well planning.
Automated Procedures - A New Way of Improving Efficiency and Safety
Authors: Wilkins Maurice J. 
Published: August 2016

Abstract
Automated procedures sound simple and yet they have not been used in the past by many of the so-called continuous industries, including upstream. As the upstream industry is looking more and more at moving to unmanned remote operations, this paper will show how major operators have obtained both operational and safety benefits by using procedure management techniques.
Procedures can be operated manually, semi-automatically and automatically. Modular Procedural Automation analyses the best practices of major operators and syntheses them into repeatable procedures. They are then presented in a format that operators can easily identify and act upon or they can be run automatically, even from a remote location.
Major owner/operators, including one major GOM operator, have found substantial savings by using procedure automation techniques. This paper will give illustrations of the benefits obtained by several owner operators by using procedure management and it will also look at the aircraft and medical industries to show how procedures have helped to improve their operations and ensure consistency and repeatability.
After the Deepwater Horizon incident major GOM operators are turning to procedure management techniques to ensure safer and more efficient operations. In terms of innovation, several of the major operators both onshore and offshore are looking at ways to operate facilities remotely and unmanned. A key requirement for this to be achieved in my opinion is the use of automated procedures
The Use of Well Integrity Management Systems & Software to Increase Organisational Understanding
Authors: Connon Stuart , Corneliussen Kjell 
Published: August 2016

Abstract
Total E&P UK (TEPUK) operates a diverse portfolio of both surface and subsea fields in the UK continental shelf. Despite a wide variety of technical design, well architecture and operating conditions of these assets it is of the upmost importance to be able to manage the wells integrity consistently at all times.
As the role of the Well Integrity Engineer continues to expand and mature within the industry, a greater focus is being given to the ability of tools utilised by the responsible engineers and the organisation to be able to quickly interrogate the Well Integrity Management database and provide concise support to well operations.
Having recognised the importance of robust well integrity management, TEPUK set an objective to increase its organisational understanding of well integrity through the use of effectively presented data.
A systematic approach to well integrity related data collection and structured archiving through the use of a single point central software system is key to ensuring that the required information is readily available and easily extractable to an organisation. This can however lead to a complex database that may be troublesome for an untrained user to navigate and interpret to find the ‘right information’. Through standard pre-generated reporting formats, personnel training and education, and a simple user interface that displays a collection of the critical information, an organisation's culture can be transformed, leading to a clearly visible increase in understanding.
This paper presents examples of the results observed that clearly demonstrate not only an increased understanding, but also an increasing sense of ownership of the tasks related to wells and subsequent management of their integrity.
Improving Data Quality in WITSML Data
Authors: Svensson Inge , Wooley Matthew , Halland Thomas 
Published: August 2016

Abstract
Data quality issues have for many decades been a problem for drilling data. To some extent, development of data transfer standards has helped out in achieving better data quality and data transport. In the early stages of WITSML, poor data quality was a concern and in this paper we will be looking at various steps that have been taken to improve data quality.
Sensor technology has improved a lot in recent years with fieldbus options which allow for remote calibration and diagnostic. In addition calibration routines are streamlined and range checks can be implemented at point of acquisition. The data acquisition software now has some inbuilt quality control to addresses errors in manual data input. In addition we have developed software at the rig-site that will perform several data quality checks in the database.
After acquisition, the data is converted and transferred to a central hosted WITSML 1.4.1.1 server. Here several applications will perform data quality assurance on the data, e.g. to check for data gaps. In addition the data flow is monitored 24/7 from an operation center before data is consumed by several applications.
We have been working closely with one operator for several years to improve processes in WITSML data deliveries. To ensure there is an agreement of what data is expected to be delivered, this company has established electronic order forms that will be sent to us for quality check before the section starts. In addition this operator has developed a sophisticated data quality monitoring system that will produce KPI scores linked to the SLA.
Some results from research in using statistics to uncover abnormal sensor response in acquired data will also be presented. Statistic will show how data quality is improving while the amount of data is acquired from one rig is increasing year by year.
Improving Weight to Weight Connection Time to Lower Well Construction Cost
Authors: Svensson Inge , Mobley Kassie E. , Aming Anthony J. 
Published: August 2016

Abstract
Even with lower rig rates due to the lower oil prices, the daily cost of running a drilling rig is still high. When an offshore rig is drilling, this can extend well over 100.000 USD an hour with all personnel and services onboard. Monitoring and improving rig and drilling key performance indicators is therefore an important factor that can lower well construction cost.
This paper will focus on how we can monitor, visualize and improve weight to weight connection time and related sub components over time. In addition we will look into real-time monitoring of weight to weight time while drilling and which corrective actions can be taken. We will express factors that are contributing to excess usage of time in some sections drilled, outlined with examples and use cases. Very often we do see large potential for improvements that again will save rig time.
Typically we can discover extended circulating time including forward and backward reaming and excess time used on taking surveys. On some rigs, we also observe slip to slip time to be below average. Wired pipe operations compared to normal mud pulse telemetry will also be presented.
Statistics will be presented with a composite average best performance for a number of wells. In our conclusion and findings, we will present documented results from rigs that have undergone rig performance programs over time and the resulted potential cost savings.
Using Nudge Techniques to Influence Behaviour in an Engineering Office
Authors: Healey M. , Parker K. , Saldin L. 
Published: August 2016

Abstract
Nudge techniques have led to a revolution in the way organisations think about the hierarchy of choice. Small changes in the way choices are presented — nudges — can have a significant impact on behaviour. This article considers the application of nudge techniques to engineering offices, a working environment populated by a high proportion of skilled professional individuals.
The techniques presented are based on the Nudge methodology, first published in 2008. The authors draw on lessons from direct experience in engineering offices, and from results presented in the public domain. This includes techniques developed by government "nudge units", such as those instituted by the Cameron and Obama governments. The techniques presented are broadly based on the EAST (Easy, Attractive, Social, Timely) framework developed in the UK and intended for application by managers within private industry.
Engineering offices present a special challenge compared with government and other industries. Managers must maintain a functional and profitable environment within an intelligent, diverse, and wilful group of employees. Nudge techniques are particularly applicable to this environment as they offer a mechanism to implement change without prescriptive rules, and without organizational upheaval. In nudge parlance this is known as "libertarian paternalism". This article looks at several potential applications, specifically: embedment and reinforcement of an organization-wide commitment to safety culture; better adherence to document control procedures; improved efficiency and general job performance; improved commercial focus; reduction of anti-social or destructive behaviour; improved office-wide communication, and; increased job satisfaction.
The nudge techniques in this paper are presented in a practical way, designed for direct use by managers. They account for the unique features and requirements of an engineering office environment, and are based on the premise that a small change can lead to significant, measurable improvements.