bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and evaluation of the n-type PbTe based material properties for thermoelectric generators
Authors: Li Tse-Hsiao , Hwang Jenn-Dong , Chu Hsu-Shen , Chen Chun-Mu , Hsu Chia-Chan , Liao Chien-Neng , Chung Hsiu-Ying , Huang Tsai-Kun , Huang Jing-Yi , Hsieh Huey-Lin
Published: March 2013

Owing to energy conservation of waste heat, Lead telluride, PbTe, based materials have promising good thermoelectric properties around a range of middle temperature (Fig. 1, from 300 to 600°C), due to their high melting point, fine chemical stability, and the high figure of merit Z. The general physical properties and factors affecting the figure of merit have been reviewed. This research is focused on the n-type of PbTe materials and collocated with analysis of densities, hardness, elastic modulus, and thermoelectric properties thermoelectric figure of merit ZT=GS2T/κ (where G is electrical conductivity, S is Seebeck coefficient , T is absolute temperature, and κ is thermal conductivity). Room temperature hardness and Young’s modulus are measured by nano-indentation. In this study, the hot-press compacts under the pressure of 4 ton/cm2 can reach the maximum density about 8.2 g/cm3, and hardness and elastic modulus are 0.6 GPa and 70 GPa, respectively. The figure of merit value (ZT) of PbTe in low temperature (around 340°C) was found about 1 with carrier concentration above 1019 cm−3. These results also indicate that the powder metallurgy parameters provide potentialities for further increase of the high efficiency of energy conversion in PbTe materials.
Thickness Dependent Optical Properties of WO3 Thin Film using Surface Plasmon Resonance
Authors: Paliwal Ayushi , Tomar Monika , Gupta Vinay
Published: March 2013

The effect of tungsten oxide (WO3) thin film thickness on the surface plasmon resonance (SPR) properties have been investigated. WO3 films of varying the thickness (36 nm, 60 nm, 80 nm, 100 nm, 150 nm and 200nm) have been deposited onto Au coated prism (Au/prism) by radio frequency (RF) magnetron sputtering technique. The SPR responses of bilayer films were fitted with the Fresnel’s equations in order to calculate the dielectric constant of WO3 thin film. The variation of complex dielectric constant and refractive index with the thickness of WO3 thin film was studied.
Quasiperiodic plasmonic concentrators for enhanced light absorption in ultra-thin film solar cells
Authors: Flanigan Patrick W. , Ostfeld Aminy E. , Ye Zhen , Serrino Natalie G. , Pacifici Domenico
Published: March 2013

This report will demonstrate broadband, wide-angle, and polarization-insensitive absorption enhancement in ultra-thin films resting on metal substrates that have been etched with arrays of shallow sub-wavelength cylindrical holes. Absorption enhancement will be studied as a function of array geometry, with particular emphasis given to quasiperiodic arrays (a class of deterministic aperiodic arrays that were originally developed to tessellate 2-D planes with regular polygons). Through simulations and experimental data, it was found that absorption enhancement is heavily dependent on the rotational symmetry of the pattern of holes, as well as the inter-hole distance.
Potential Driven Chemical Expansion of La0.6Sr0.4Co1-xFexO3-δ Thin Films on Yttria Stabilized Zirconia
Authors: Chang Kee-Chul , Ingram Brian J. , Hopper E. Mitchell , Yan Miaolei , Salvador Paul , You Hoydoo
Published: March 2013

To better understand the response of oxygen vacancy concentration to applied potential, the lattice parameter of pulsed laser deposited La0.6Sr0.4Co1-xFexO3-δ thin films was monitored using in situ X-ray diffraction. We demonstrate that the chemical expansion under applied potential depends on the cathode morphology, which determines the contribution of different reaction pathways. We investigated applied potential dependent lattice expansion on La0.6Sr0.4Co1-xFexO3-δ with 3 different Co:Fe ratios in an attempt to connect bulk chemical expansion data to thin films. We find that the chemical expansion trends in thin films are different than expected from bulk data.
The Effect of γ-radiation on Mechanical Properties of Model UK Nuclear Waste Glasses
Authors: McGann Owen J. , Gandy Amy S. , Bingham Paul A. , Hand Russell J. , Hyatt Neil C.
Published: March 2013

The effect of γ-radiation on the mechanical properties of model UK intermediate and high level nuclear waste glasses was studied up to a dose of 8 MGy. It was determined that γ-irradiation up to this dose had no measurable effect upon the Young’s modulus, shear modulus, Poisson’s ratio, indentation hardness, or indentation fracture toughness. The absence of measurable radiation induced changes in mechanical properties was attributed to redox mediated healing of electron-hole pairs generated by γ-irradiation by multivalent transition metal ions, in particular the Fe3+ - Fe2+ couple.
XAFS Study of Fe K Edge in Al2O3-B2O3-Fe2O3-Na2O-SiO2 Glasses
Authors: Stefanovsky S.V. , Shiryaev A.A. , Zubavichus Y.V. , Fox K.M. , Marra J.C.
Published: March 2013

Valence state and local environment of Fe in complex glasses related to the system Al2O3-B2O3-Fe2O3-Na2O-SiO2 were studied. In all the glasses, the major fraction of Fe exists as Fe3+ ions but a minor fraction of Fe2+ ions especially in the glass with the lowest K=[SiO2]/[B2O3] ratio was also present. Average Fe—O distance in the first shell is 1.80-1.85 Å and coordination number is 4-6. The intensity due to the second sphere is rather weak demonstrating homogeneous distribution of Fe ions in the glass.
Exfoliated ∼25μm Si Foil for Solar Cells with Improved Light-Trapping
Authors: Saha S. , Onyegam E. U. , Sarkar D. , Hilali M. M. , Rao R. A. , Mathew L. , Jawarani D. , Xu D. , Smith R. S. , Das U. K. , Fossum J. G. , Banerjee S. K.
Published: March 2013

Investigation of optical absorption in ∼25μm thick, monocrystalline silicon (Si) substrates obtained from a novel exfoliation technique is done by fabricating solar cells with single heterojunction architecture (without using intrinsic amorphous silicon layer) with diffused back junction and local back contact. The ease of process flow and the rugged and flexible nature of the substrates due to thick metal backing enables use of various light-trapping and optical absorption enhancement schemes traditionally practiced in the industry for thicker (>120μm) substrates. Optical measurement of solar cells using antireflective coating, texturing on both surfaces, and back surface dielectric/metal stack as mirror to reflect the long wavelength light from the back surface show a very low front surface reflectance of 4.6% in the broadband spectrum (300nm-1200nm). The illuminated current voltage (IV) and external quantum efficiency (EQE) measurement of such solar cell shows a high integrated current density of 34.4mA/cm2, which implies significant internal photon reflection. Our best cell with intrinsic amorphous silicon (i-a-Si) layer with only rear surface textured shows an efficiency of 14.9%. EQE data shows improved blue response and current density due to better front surface passivation. Simulations suggest that with optimized light trapping and surface passivation, such thin c-Si cells can reach efficiencies >20%.
Point Focus Solar Spectral Splitting System for CPV Applications
Authors: Zayan Ahmed , Chiesa Matteo , Stefancich Marco
Published: March 2013

Solar spectral splitting technologies have been investigated over the years as alternatives to improve the efficiencies obtained from photovoltaic devices by splitting the incident solar light into its respective wavelengths, and aligning a series of photovoltaic cells arranged next to each other as opposed to being physically stacked on top of each other as is the case with multijunction cells. Limitations previously posed by multijunction cells like current matching and lattice matching are circumvented through this approach, allowing for a broader and potentially cheaper pool of candidate cells to be used for energy conversion. In this study, we design and gauge the performance of a single optical element capable of splitting the light and concentrating it simultaneously unto a bed of photovoltaics, each illuminated by the part of the spectrum that corresponds best to its relevant properties such as the bandgap and the external quantum efficiency. The prismatic structure constituting the device relies on the device’s transmission in the visible region and its dispersion. Presented in this study is the mathematical framework used in designing the structure for a specific merit function; in particular, the study focuses on minimizing optical losses at the interfaces of the structure with the ambient air. Variables like the index of refraction of the material used, the angle of incidence on the surface, the exit angle of the light out of the structure factor into the optical center’s design. Compared to alternative splitting technologies like dichroic mirrors, the model splits the incident polychromatic light into a continuous band of wavelengths as opposed to discrete wavelengths that can be adapted on to different sets of single junction cells. The device is an improvement to our published 1-axis linear concentrator reported earlier in the year for its point-focus output yielding in even higher concentration and potentially lowers costs.
Development of High Temperature Optical Interference Filters
Authors: Parker Thomas C. , Demaree John D.
Published: March 2013

Oblique angle deposition (OAD) is a self-organizing physical vapor deposition (PVD) technique that has been used to grow sculpted 3D nanostructures including helices, slanted rods, and zigzag structures, and other shapes. OAD structures can be fabricated from virtually any material that can be deposited using PVD including: polymers, metals, semiconductors, oxides, and nitrides. The control over the nano-scale structural anisotropy of these materials allows one to tailor their electrical, magnetic, mechanical, crystalline, and optical properties. Through the careful design of the OAD structure and material selection this technique can be used to create photonic materials (1D, 2D, and 3D) with unique properties. We will discuss ongoing work using OAD to develop oxide thin film interference filters that can withstand extreme temperatures (800-1000° C) at mTorr vacuum levels, which are being developed for thermal photovoltaic applications.
Functional voids by gas ion implantation for applications in semiconductor processing
Authors: Raineri V. , Rimini E.
Published: March 2013

The recent work in the field is reviewed and some new applications are reported. In particular we review some aspects where new contributions have been added. The mechanism of bubble formation when He is implanted into silicon is described till the supersaturation of vacancies (void formation). The void evolution has been described considering direct coalescence or Ostwald ripening. Applications such as gettering, lifetime control, and more recently nanosensors for interstitials are critically discussed.
GNSS/NTRIP service and technique: accuracy tests
Authors: Cintra Jorge Pimentel , Nero Marcelo Antonio , Rodrigues Danilo
Published: March 2013

Experiments conducted at the School of Engineering of the University of São Paulo, Brazil, using GNSS/NTRIP technology are described and analyzed in terms of accuracy. The method consists in using the data of a reference station, the IBGE RBMC-IP stations, collected in a remote station, by means of the Internet and a mobile phone, to obtain more accurate real time coordinates than those of the navigation method. The experiments consist in surveying the known coordinate points and of the error analysis (accuracy). Firstly with short distances (in the USP Base for Equipment Calibration), and then over increasing distances up to about 30 km, in terms of the limits foreseen for the RTK method, and for other greater distances by using the DGPS method, up to 2,700 km. The following were tested and analyzed: the use of different reference stations, the variation in accuracy over distance, the use of a L1 receiver and a L1/L2 one, as well as the use of the RTK and DGPS techniques, in terms of accuracy reached, that is, the difference between these coordinates and others considered as standard, besides checking if the equipment reaches or not the accuracy stated in the manual.
Industry Analogies for Successful Implementation of Drilling Systems Automation and Real Time Operating Centers
Authors: de Wardt John P
Published: March 2013

Industry analogies provide excellent insight to finding the optimum balance among manual, automatic and remote operations. They can also provide excellent insight into data displays and decision making.

It is very important to define current state and future desired state for data acquisition, processing, decision making and work flow in high performance drilling operations. Understanding the difference between these two states provides the opportunity to guide the successful implementation of Drilling Systems Automation (DSA) and Real Time Operations Centers (RTOC's). Aviation and space flight have been offered as appropriate analogies for the future application of drilling systems automation. Formula One (F1) motor racing offers a highly competitive analogy for managing data flows combined with control systems.

Various industry analogies are reviewed for their applicability to DSA and RTOC's. The benefits and drawbacks of each are highlighted. An assessment utilizes insights from other analogous industries to provide the opportunity to define best practices and relevant application for various well types from these analogies.

Advanced application of DSA and RTOC's will change the role of the driller as well as the competency make up and location of the drilling team. Maximum benefit from DSA and RTOC's can be achieved through carefully planned implementation based upon relevant learning from other industries.
Planning for Successful Jarring Operations - Effective Use of Drilling Impact System Helps Release Stuck Pipe
Authors: Mercado Jose L
Published: March 2013

Jarring is a cost effective alternative to free stuck pipe. Impact tools have been used in drilling industry for many decades and the technology has helped operators save significant amounts of time and money. To keep improving this technology, a new Drilling Impact System (DIS) has been developed. The DIS uses innovative double-acting hydraulic Drilling Jar/Drilling Accelerator and BHA analysis software. The unique modeling program enables engineers to identify/recognize the optimum impact/impulse values and key operational considerations during the BHA design process. The optimized BHA with accelerator amplifies the energy created by the drilling jar. As a consequence, it increases the probability of freeing a stuck BHA.

This paper focus on the drilling bottom hole assembly (BHA) design process and best operational practices to ensure a successful drilling operation. The author will discuss effectiveness of the impact system and proper pre-job analysis procedures for optimum jar placement to avoid lost-in-hole (LIH) situations. The planning process includes: 1) operational considerations; 2) QA/QC system and; 3) software analysis. Case studies are presented to illustrate how the utilization of the drilling impact system culminated in the successful execution of a jarring operation to free stuck bottom hole assemblies.
Innovative Managed-Pressure-Cementing Operations in Deepwater and Deep Well Conditions
Authors: Elmarsafawi Youssef , Beggah Amor
Published: March 2013

Managed-pressure drilling (MPD) was developed to help drill wells that have a very close pore and frac pressure gradient. Commonly required in soft marine sediments and in shallow land drilling, MPD is also used in specific cases, such as deep wells. Cementing operations in such conditions are very challenging and require special attention to cement the string while reducing risk of losses or flow. The innovative managed-pressure-cementing technique (MPCT) was used to cement several string sizes that sat at different depths ranging from 2,000 m up to 6,500 m, in water depth exceeds 1,000 m. In this challenging deepwater environment, specialized surface equipment was used to control the well during cementing. In addition, the mud properties and cement system were tailored for this specific operation.

This paper illustrates the importance of MPCT in wells cementing operations to minimize cement and mud losses, secure well during cementing and reduce risk of formation damage. After cementing, the jobs were evaluated using different techniques including observation of fluids returns at seabed, end of job pressure versus simulated job pressure and with sonic and ultrasonic logging tools. The success of the MPCT enabled us to reduce completion costs and achieve drilling objectives.
HPHT Well Construction with Closed-Loop Cementing Technology
Authors: Hannegan Don , Dunn Tim , Moore Dennis , Gray Ken
Published: March 2013

Achieving successful isolation of potential flow zones during well construction in deep fault-segmented HPHT basins is often a formidable task. These wells, often drilled from floating rigs, tend to present rapid departures from more normal conditions to very high degrees of overpressure, elevated temperatures and where formation pressures often approach fracture gradient. Further, once overpressure is geologically established in isolated pressure compartments, reservoir fluids tend to migrate vertically via hydro-fracturing to shallower depths.18

Challenges associated with cementing operations include actual leak-off test value (LOT) vs. predicted, margins of error in mud weights estimated, and risk of inducing a fracture during pre-flush and slurry displacement. If the open hole was under-reamed, the actual fracture pressure may be reduced by an unknown amount. ‘Wellbore strengthening’ operations and associated procedures add additional formation fracture gradient uncertainty.4

This presentation speaks to applying the principals of Managed Pressure Drilling (MPD) and recent refinements of its practice to cementing processes. Precise flow in/out measurements in real-time, ascertainment of actual downhole pressure environment, ability to conduct frequent dynamic formation integrity tests (FIT's) without drilling interruption and use of PLC choke systems are applicable strengths.19,20,22

API Standard 65 - Part 2, Second Edition, December 2010 - Isolating Potential Flow Zones during Well Construction will be referenced to illustrate C-LC applications.

Preparatory - quantify the stability of the wellbore with frequent dynamic FIT's (without exercising the BOP) and assurance of hole cleaning during pre-flush.

Displacement - optimize fluid dynamics and ascertain in real-time an induced fracture.

Curing - maintain more consistent annulus pressure on rigs experiencing wave heave, backpressure applications for minimizing the risk of channeling and/or help ensure the column of plug in the tubing string is balanced with the annulus

Testing - Use of a rotating control device (RCD) and process logic controlled (PLC) Choke to pressure test plugs after tagging in lieu of using dedicated cementing equipment.
Extended Reach Drilling - new solution with a unique potential
Authors: Vestavik O. , Egorenkov M. , Schmalhorst B. , Falcao J.
Published: March 2013

The Reelwell Drilling Method (RDM) is a new drilling method, developed and qualified for commercial use during recent years. RDM is a multi-purpose drilling method with a unique flow arrangement. RDM is based on using a conventional drill string combined with an inner string to form a dual conduit drill string. This arrangement allows the return fluid, containing drill cuttings from the bottom of the well, to be transported back through the inside of the drill string.

RDM has the potential to increase the envelope for Extended Reach Drilling (ERD) for several reasons:

– Torque and Drag reduction, due to use of a flotation technique of the drill string. – Elimination of the dynamic Equivalent Circulating Density (ECD) gradient, since the ECD is screened from the formation. – Optional Hydraulic Weight On Bit (WOB), due to a piston type arrangement at the drill string.

The following presents a case study for an ultra ERD RDM application. In this case, the RDM arrangement involves the use of a special dual conduit aluminium drill string and the use of two different density fluids in the well during drilling. A calculation example of a fully buoyant drill string is also presented. This situation indicates that the well can be drilled with very high operational margins on the equipment and at the same time, the wear will be very low. The simulations indicate that the extreme ERD well of 15.8 km depth can be drilled with good margins, mainly due to flotation of the drill string. It is shown that the well can be cased and lined, using conventional flotation techniques in combination with RDM.
Autonomous Robotic Drilling Systems
Authors: Søndervik Kenneth
Published: March 2013

Over the last decades we have seen many improvements in drill floor automation. Common for many of these have however been more in line of "make a machine to duplicate manual labor". This is about to change. Over the last 5 to 6 years more and more companies and resources have been focusing on creating fully automatic systems, and in the last couple of years we have seen the introduction of fully robotized systems.

This paper will highlight some of the vast improvements seen in Health and Safety as well as efficiency measured in both time and money when using robotics in the drilling operations. This will be true for most, if not all, drilling structures designed for land or offshore operations either used for drilling for hydrocarbons or not.

We will discuss how fully robotized drill floor, and even small partly intelligent tools can make a big difference, for both safety and cost savings.

This effectiveness and safety aspect will be further improved when using autonomous decision making systems. With autonomous system we mean that the systems itself will have the ability to decide how to perform a given task more safely and with a higher efficiency than a preprogrammed task.
Automated Alarms for Smart Flowback Fingerprinting and Early Kick Detection
Authors: Ali Tarab H. , Haberer Sven M. , Says Ian P. , Ubaru Charles C. , Laing Moray L. , Helgesen Olav , Liang Max , Bjelland Bente
Published: March 2013

Recent events and studies show that wellbore stability and geopressure events continue to plague the oil industry with issues that affect the safety of people and the environment. In addition, events such as kicks and lost circulation also create significant loss of time and productivity, commonly referred to as non-productive time (NPT). Deepwater studies have shown NPT related to kicks, and lost circulation can amount to 4.5% of the total well construction time. Consequently, early kick and lost circulation detection is crucial to eliminating detrimental effects on human and environmental safety, in addition to minimizing NPT.

Kicks frequently happen during connections, and flowback fingerprint monitoring has been used for more than a decade across the industry to aid in kick detection. However, setting alarm thresholds and identifying abnormal flowbacks has been a manual process that relies heavily on the experience and intuition of the engineer who performs this critical safety monitoring. This manual process frequently misses early signs of influx, and thus greatly increases the well remediation time.

This publication focuses on the development and deployment of an automated flowback monitoring technology. The new solution aids drillers and drilling engineers by generating intelligent alarms relevant to current well conditions for early kick and loss detection, which can result in detecting kicks up to one connection earlier than the existing manual method. This paper demonstrates the benefits of Smart Flowback Fingerprinting over existing practices and how it can significantly reduce safety risks and NPT.
Implementation of PMCD to Explore Carbonate Reservoirs from SemiSubmersible Rigs in Malaysia results in Safe and Economical Drilling Operations
Authors: Jayah M Noreffendy , A Aziz Intan Azian , Mathews Travis , Voshall Allan , Rojas Rodriguez Freddy
Published: March 2013

PETRONAS has been drilling carbonate reservoirs offshore Sarawak since the 90's. However, with more prospects being explored, the challenges have escalated as the company has embarked into exploring the remaining carbonate pinnacles where the primary objective is to identify the gas or oil water contacts of the prospects. Some of these carbonate reservoirs are characterized by the presence of large karsts and fractures, leading to a frequent scenario of total mud losses and kicks. Conventional drilling practices are not considered a safe or economical option to drill the carbonate sections. Additional problems associated with the drilling operation in these zones includes poor hole cleaning, low ROP, high vibrations and stuck pipe events.

Implementing the Managed Pressure Drilling (MPD) variant called Pressurized Mud Cap Drilling (PMCD) allowed the drilling team to reach targeted total depths on several wells. Upon encountering unsustainable losses the wells were converted over to PMCD. Light Annular Mud (LAM) was injected into the annulus and a sacrificial fluid (SAC) was pumped down the drillstring allowing drilling to continue to total depth.

By successfully implementing the PMCD technique, the operator was able to reduce risk and reach the exploration targets successfully. Lessons learned surrounding operational techniques, pressure limitations of the drilling system and continuous training and development of the operating team have expanded the application for the operator.

The authors present lessons learned of wells drilled to date and key lessons learned as the Operator evolves to improve execution of PMCD.
A New Standard in Wireline Coring: Recovering Larger Diameter Wireline Core through Standard Drill Pipe and Custom Large Bore Jar
Authors: Farese Travis , Ahmed Hammad , Mohanna Assaad
Published: March 2013

Wireline retrievable coring is a unique technology offering capabilities to full bore core, drill and convey logs in a continuous operation without tripping out of hole. This technology saves considerable time compared to multiple conventional coring runs. The time and cost savings increase significantly where there is a need to drill between coring intervals as applies in hole sections with multiple objectives.

However, one of the constraints with large diameter wireline coring systems is the requirement to pick up specialty drill pipe. This specialty drill pipe provides an internal diameter large enough to accommodate the retrieval of the inner components utilized to cut 3 to 3.5 inch diameter core. A further constraint with large diameter wireline coring systems is the inability to run a jar within the drill string due to internal diameter limitations.

A new wireline retrievable system capable of acquiring 3 inch diameter core utilizing standard drill pipe was designed for an application in Middle East. In addition, custom large bore coring jars were designed and deployed to meet the operator's stuck pipe prevention standards. A total of 215 ft. of core was cut on the first trial well in 8 3/8 inch hole size achieving 98.6% core recovery, excellent core quality and 74-hrs of rig time savings compared to conventional coring operations.

The improvement in this technology has drastically increased the efficiency of large diameter wireline retrievable coring technology, decreased the stuck pipe risk and greatly reduced the minimum amount of core needed for the technology to be economically justified.
Qualification and Field Trial of a Metal Expandable Well Annular Barrier
Authors: Drechsler Jan Roar , Eikeskog Øystein , Hazel Paul , Vasques Ricardo , Filev Boris , Bårdsen Johnny , Hjorteland Øyvind
Published: March 2013

The ability of cement to achieve a pressure seal across the reservoir section for the life of a well becomes ever more difficult to achieve because of increasing depths and more complexity in well design and operations. Mature fields with depleted zones combined with the desire and ability for extended reach wells exacerbates the challenge of delivering a cement-only, fit-for-purpose liner.

To address this challenge, an operator and service company have joined forces to design, develop, and qualify a hydraulically expandable metal well annular barrier (WAB) assembled on the outside diameter (OD) of a liner while maintaining full-bore inner diameter (ID). Intended initially for use in Norway's Valemon field, the operator is also exploring options for other applications in the Snorre and Brage fields, also offshore Norway.

This paper discusses the design, development, and qualification of the metal WAB, including: review of the design, material selection to achieve the required expansion, the unique outer seal design to deliver the pressure differential requirements, and intended applications to date. The final qualification process exceeds the industry-established guidelines in ISO standard 14310 (which defines requirements for packers and bridge plugs for the oil and gas industry).
The Next Step in Conventional Reciprocating Mud Pump Technology
Authors: Berryhill Gregg , Shelton Andy
Published: March 2013

Recent developments in reciprocating mud pump technology provide added value for operators, drilling contractors, and MWD/LWD (measurement while drilling/logging while drilling) service providers. Utilizing current proven conventional triplex (3-cylinder) pump designs and adding two cylinders provides an increased performance envelope, reduces pulsations on the rig structure and piping, and substantially increases data rate-transfer bandwidth during MWD/LWD operations.

Current data rate transfer for MWD/LWD when using reciprocating pumps are limited to frequencies below the first dominant frequency. Using a comparable horsepower quintuplex (5-cylinder) pump increases the data transfer rate 66% over current triplex reciprocating pumps. Due to the shorter stroke of a comparable horsepower quintuplex pump, the pump can also be operated at higher stroke rates that produce an additional 33% gain in frequency bandwidth. This is achieved through increased frequency of the additional pump cylinders and the ability to operate the pump at higher pump speeds.

The inherent design attributes of conventional quintuplex pumps reduce fluid flow variation (pulse) versus comparable horsepower triplex pumps. The five operating cylinders are timed at 72° whereas conventional triplex pumps are timed at 120° intervals per 360° of pump rotation. The additional cylinders reduce flow variation of the quintuplex to 7 percent versus a 23 % flow variation for conventional triplex pumps.

This paper focuses on advantages of using a conventional five cylinder design horizontal mud pump versus an equivalent horsepower conventional three cylinder design. For comparison a EQ-2200 will be tested versus a E-2200.The discussion includes specification comparisons, weights, external envelope dimensions and comparisons of fluid flow variation (pulse) performance that translates into reduced vibration on the rig and increased MWD/LWD data rate transfers.

The EQ-2200 is a 2,200 horsepower quintuplex pump and the E-2200 is a 2200 horsepower triplex pump. Both pumps are crankshaft-slider driven and both are rated at 7500 PSI working pressure.

Though both series have equivalent horsepower, in contrast, the pulse signature of the EQ series is greatly reduced compared to that of the E series, thereby increasing the performance envelope for MWD/LWD operations. In addition weights and dimensional envelopes of the EQ series are less than the E series.
Pore Pressure Evolution, Core Damage and Tripping Out Schedules: A Computational Fluid Dynamics Approach
Authors: Zubizarreta Izaskun , Byrne Michael , Sorrentino Yelitza , Rojas Elinor
Published: March 2013

During coring operations, while tripping out of the hole, core is submitted to a relatively sudden decrease in pressure, leading to fluid expansion and movement out of the pore space. The rapidly expanding fluids can generate fractures and damage the core. Tripping out core represents a delay to well drilling operations, therefore, project economics dictate "efficient" tripping out schedules given high daily rig costs. Ideally, core tripping out rates should be established for each particular core; however common practice is based on generic rules of thumb. The resulting schedules can lead to unjustifiably long tripping out operations or core damage if the process is too fast. There is a lack of clarity and consensus regarding tripping schedules impacting on both the integrity of the core and the economics of coring/drilling operations.

With these high daily rig costs in mind, a more scientific and quantitative approach, tailored to each case is required. The application of Computational Fluid Dynamics (CFD) is used to model transient pressure differentials in a gas reservoir core during retrieval.

The results of theoretical and field case simulations support and confirm empirical evidence that the pressure differentials created in a core during retrieval, are very low for relatively high permeability rock, and that most core tripping schedules based on rules of thumb significantly overestimate time, to the detriment of drilling efficiency. As the core permeability decreases, the time required for the core internal pressure to approach the external pressure increases, requiring longer equilibration times. The model realisations demonstrate that tensile failure criteria are more likely to be reached during the final stages of tripping out.

This study demonstrates that CFD can accurately predict the pressure differentials created in a core during retrieval to surface and enables proper planning of tripping times based on the assessment of potential damage by pressure release.
Performance of Thermal Cements with Different Weighting Materials
Authors: Caritey Jean-Philippe , Brady Jason
Published: March 2013

As the world's demand for energy continues to grow, exploration and production activity increasingly involves operations in high-pressure, high-temperature (HPHT) conditions. HPHT domains include geothermal, steam-injection, and ultradeep wells. These environments introduce difficult technical challenges. A major concern is the set-cement integrity. To maintain zonal isolation throughout the life of an HPHT well, the cement sheath must perform reliably at temperatures that can exceed 315°C [600°F]. When exposed to temperatures higher than 110°C [230°F], set Portland cement undergoes strength retrogression unless additional silica is incorporated in the cement formulation. This phenomenon has been studied extensively. However, less attention has been paid to the effects of other additives on the stability of set Portland cement in an HPHT environment—weighting materials in particular. Weighting materials have largely been assumed to be inert with respect to set Portland cement; however, the present study reveals that this assumption may be false in HPHT environments in which well temperature exceeds 260°C [500°F]. Some weighting agents may react with the set Portland cement, causing strength loss and increased permeability. Fortunately, this effect can be prevented, and the set-cement integrity can be preserved.
System Reliability and Metrics for High-Speed Networked Drillstring Telemetry and Along String Evaluation
Authors: McCubrey Raymond , Johnson Aaron , Adsit Rhys , Veeningen Daan , Pixton David
Published: March 2013

High-bandwidth downhole data transmission via a wired or networked drill string system provides an alternative to conventional wireless telemetry to obtain real-time downhole data during well construction operations. With an unprecedented rate at three orders of magnitude faster (57,600 bps) than wireless systems, networked drillstrings offer twoway broadband communication. In addition, real-time pressure and temperature measurements are uniquely available from multiple discrete measurement stations along the drillstring.

Industry-wide adoption of this technology necessitates the system to lower well construction expenditure through increased efficiency, improved wellbore quality and reduced risk exposure to be considered as a viable alternative to conventional strings. In addition, system reliability must be demonstrated with useful metrics. Mean Time Between Failure (MTBF) is one such metric used in the industry to measure reliability. High values of a system MTBF generally indicate a reliable product when combined with other metrics.

This paper provides historical trends of MTBF, and other reliability metrics in the case of high-speed networked telemetry drillstrings. The data and most conclusions are based on a reliability study from 65 wells that were drilled from 2008 to 2011. Results show increasing trends in reliability. Future improvements to network drillstring are discussed and their effect on reliability through these estimates is forecasted.
Autologous blood transfusion in total knee replacement surgery
Authors: Lukic-Sarkanovic Mirka , Gvozdenovic Ljiljana , Savic Dragan , Ilic Miroslav , Jovanovic Gordana
Published: March 2013

Background/Aim. Total knee replacement (TKR) surgery is one of the most
frequent and the most extensive procedures in orthopedic surgery, accompanied
with some serious complications. Perioperative blood loss is one of the most
serious losses, so it is vital to recognize and treat such losses properly.
Autologous blood transfusion is the only true alternative for the allogeneic
blood. The aim of this study was to to examine if autologous blood
transfusion reduces usage of allogenic blood in total knee replacement
surgery, as well as to examine possible effect of autologous blood
transfusion on postoperative complications, recovery and hospital stay of
patients after total knee replacement surgery. Methods. During the
controlled, prospective, randomised study we compared two groups of patients
(n = 112) with total prosthesis implanted in their knee. The group I
consisted of the patients who received the transfusion of other people?s
(allogeneic) blood (n = 57) and the group II of the patients whose blood was
collected postoperatively and then given them [their own (autologous) blood]
(n = 55). The transfusion trigger for both groups was hemoglobin level of 85
g/L. Results. In the group of patients whose blood was collected
perioperatively only 9 (0.9%) of the patients received transfusion of
allogeneic blood, as opposed to the control group in which 98.24% of the
patients received the transfusion of allogeneic blood (p ? 0.01). The
patients whose blood was collected stayed in hospital for 6.18 days, while
the patients of the control group stayed 7.67 days (p < 0.01). Conclusion.
Autologous blood transfusion is a very effective method for reducing
consumption of allogenic blood and thus, indirectly for reducing all
complications related to allogenic blood transfusion. There is also a
positive influence on postoperative recovery after total knee replacement
surgery due to the reduction of hospital stay, and indirectly on the
reduction of hospital costs.
Lipoma of the sigmoid colon
Authors: Djolai Matilda , Andrejic Bojana , Ivanov Dejan
Published: March 2013

Introduction. Lipoma is a benign tumor of adipose tissue, the most common
tumor of the human body soft tissues. As such, it can be found almost
anywhere in the human body including the gastrointestinal system (incidence
below 0.5%), but rarely in the sigmoid colon. Case report. This is a case
report on symptomatic polyp of the sigmoid colon, which after one year, at
control colonoscopy, caused suspicion to malignancy. Endoscopically diagnosed
polipoid lesion was laparoscopically removed. The pathohistological diagnosis
determined benign, submucosal, incapsulated lipoma of the sigmoid colon.
Conclusion. Although lipomas of the gastrointestinal tract are rare, this
case clearly indicates that we should not prematurely and without
histological confirmation of malignancy do more extensive resection for a
suspected malignancy.
A rare case of retroperitoneal malignant triton tumor invading renal vein and small intestine
Authors: Mijovic Zaklina , Mihailovic Dragan , Zivkovic Nikola , Kostov Milos , Zivkovic Sladjana , Stojanovic Nebojsa
Published: March 2013

Introduction. Malignant Triton tumor is a very rare malignant peripheral
nerve sheath tumor with rhabdomyosarcomatous differentiation. Most of those
tumors occur in patients with von Recklinghausen?s disease or as a late
complication of irradiation and commonly seen in the head, neck, extremities
and trunk. Case report. We reported retroperitoneal malignant Triton tumor in
a 57-year-old female patient. Skin lesions were not present, and there was no
family history of neurofibromatosis or previous irradiation. The presented
case is one of a few recorded in the specialized literature that occurs in
the retroperitoneal space in sporadic form. In this case, tumor consisted of
a multilobular mass was in close relation with the abdominal aorta and
inferior vena cava and involved the renal vein with gross invasion of the
small intestine. The patient underwent total resection of the tumor and left
nefrectomy was performed. The small intestine 10 cm in length was also
resected and end-to-end anastomosis was conducted. The postoperative course
was uneventful and the patient was discharged from the hospital ten days
after the surgery. Conclusion. Diagnostically, it is crucial to recognize
this uncommon histological variant because malignant Triton tumor has a worse
prognosis than classic malignant peripheral nerve sheath tumor does. The use
of the immunohistochemistry is essential in making the correct diagnosis.
Only appropriate pathological evaluation supported by immunostaining with
S-100 protein and desmin confirmed the diagnosis. Aggressive surgical
management treatment improves the prognosis of such cases with adjuvant
radiotherapy.
Logarithmic inventory model with shortage for deteriorating items
Authors: Khedlekar Uttam , Shukla Diwakar , Chandel Raghovendra
Published: March 2013

In this paper, we have modeled a business which starts with shortage of
deteriorating items. After a duration, managers have freedom to order the
stock of assurance of committed customers. There are many products that
follow logarithmic demand pattern, so in this paper we incorporate it with
the shortage of items at the beginning. A new model is developed to obtain
the optimal solution for such type of market situation and have obtained some
valuable results. Numerical examples and simulation study is appended along
with managerial insights.
Validation of a modified McGill Pain Questionnaire for orthodontic patients
Authors: Iwasaki Laura R. , Freytag Larissa E. , Schumacher Charles A. , Walker Mary P. , Williams Karen B.
Published: March 2013

Objective:

To assess better and more efficiently the aspects of pain experienced by adolescent orthodontic patients, the McGill Pain Questionnaire-Short Form (MPQ-SF) was modified (MMPQ-SF) and validated.

Materials and Methods:

Internal and external expert panels developed a MMPQ-SF with 15 descriptors and 4-point Likert severity scales (MMPQ-SF15). Seventy-five subjects undergoing orthodontic treatment gave informed consent. Sixty-one subjects completed the MMPQ-SF15, a visual analogue scale (VAS), and the present pain index (PPI) 24 hours after an orthodontic visit. Respondents were grouped by gender and treatment stage: initial (15 female, 7 male), middle (10 female, 7 male), and end (16 female, 6 male). MMPQ-SF, VAS, and PPI scores were compared by Spearman correlation analysis. Underlying constructs were explored by factor analyses. Construct validity of the MMPQ-SF was tested by analysis of variance.

Results:

MMPQ-SF15 and VAS (r  =  0.78, r2s  =  0.61, P < .0001), MMPQ-SF15 and PPI (r  =  0.84, r2s  =  0.71, P < .0001), and VAS and PPI (r  =  0.70, r2s  =  0.48, P < .0001) were correlated positively and significantly. A two-factor solution (localized and generalized/emotional pain; Kaiser-Meyer-Olkin  =  0.88) showed that 11 descriptors (MMPQ-SF11) accounted for 64% of response variability. Generalized/emotional pain values were significantly higher during the initial stage of treatment compared to the middle (P  =  .011) and end stages (P  =  .014).

Conclusions:

MMPQ-SF, particularly MMPQ-SF11, demonstrated utility in assessment of localized and generalized/emotional aspects of pain in adolescent orthodontic patients and correlated well with VAS and PPI. Future application of the MMPQ-SF11 to measure orthodontic pain more specifically could lead to more appropriate management of this important facet of therapy.
Induction of hairy roots in Arnica montana L. by Agrobacterium rhizogenes
Authors: Petrova Mariya , Zayova Ely , Vlahova Mariana
Published: March 2013

The induction of hairy roots in Arnica montana L. by Agrobacterium rhizogenes mediated system was established. The frequency of genetic transformation varied from 4.8 to 12% depended on method of infection. The cefotaxime at concentration of 200 mg/l proved to suppress effectively the growth of A. rhizogenes after co-cultivation. Among the three tested nutrient media: Murashige and Skoog (MS), Gamborg’s (B5) and Schenk and Hildebrandt (SH), MS medium was superior for growth and high biomass production of transformed roots compared to other culture media. After culturing for 40 days the fresh weight of clone T4 increased 7.6 fold over the non-transformed roots. The transfer of rol A, rol B and rol C genes into Arnica genome was confirmed by PCR analysis. Established genetic transformation techniques in A. montana efficiently provided and generated a large number of transformed roots — an excellent system for studying gene function and could be used for the production of secondary metabolites synthesized in roots.
Evaluation of Stability of Potential Betaadrenolytics in Various Solutions by thin Layer Chromatography and by Kinetics of Hydrolysis
Authors: Stankovičová M. , Bezáková Ž. , Mokrý P. , Csöllei J. , Pažitná M. , Liptáková B. , Ševčíková Z. , Dvořáková – Kotlíková S.
Published: March 2013

The aim of this work is the study of stability and kinetics of hydrolysis of the chosen compounds, derivatives of 2-hydroxy-3-[2-(4-methoxyphenyl)ethylamino]propyl-4- [(alkoxycarbonyl)amino]benzoates and 2-hydroxy-3-[2-(2-methoxyphenyl)ethylamino] propyl-4-[(alkoxycarbonyl)amino]benzoates with potential ultra-short beta-adrenolytic activity. The studied compounds are different in the position of the substituent on the benzene ring in the side chain as well as in the aromatic ring in position 4 with alkyl- (methyl- to butyl-) carbamate. Thin layer chromatography and UV-area spectrophotometry are used in order to establish the stability of these potential pharmaceuticals. The stability studies of the compounds were examined in acidic and alkaline media, in buffers and due oxidation at room and at elevated temperature chromatographically, and Rf values of incipient products and degradation products were detected. Kinetics of acid and base hydrolysis in various solutions at temperatures 80 °C and 100 °C were examined through UV-area spectrophotometry. Kinetic parameters such as rate constant k, half-life period t1/2 and usable life t90 were determined.