bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing Marine Geohazard Risks over the Full Business Cycle
Authors: Hill Andrew W. , Wood Gareth A.
Published: March 2015

Until the offshore industry stepped off the continental shelf, the main marine geohazard risk addressed from geophysical data was the presence of shallow gas. Presence had been described using a number of non-standard approaches for its potential presence – distinct from the actual risk it presented to operations. In the 1990 “UKOOA Guidelines for the Conduct of Marine Rig Site Surveys,” a standardised nomenclature was suggested that was largely taken up as a standard by the industry.

At around this point in time, the industry had begun a move off the shelf and into deep water and, with this, a number of new geohazard issues started to present themselves (e.g. shallow water flow, chemosynthetic communities, hydrates and slope instability) for which the industry had no standard approach to assess the risk such hazards presented or to reliably define their presence.

Today the industry is faced with entry into frontier areas, with little prior published understanding, potentially complex slope and deep-water settings, and where the sources of geohazard risk to drilling and developments may be multiple, over printed, and inter-related.

In such settings, early effort in the exploration and production cycle is required to allow appropriate data to be gathered and assessed in appropriate time for drilling and facilities engineers either to avoid identified hazards, or mitigate their presence through appropriate engineering design.

In order to address these issues, BP has adopted a methodology to manage geohazard risks over the “Life of Licence,” starting with assessments of fundamental geohazard complexity and manageability on entry to a frontier area, at the basin or fairway scale, and thence defining an ongoing work programme to support continued refinement in understanding through to and including the abandonment phase.

This includes:

Suggested specific risking criteria for the presence of individual geohazard elements at a well location such that engineers can clearly, and consistently, understand potential hazard presence, Early definition of required data acquisition needs and integrated studies for field development to adopt appropriate risk mitigation methods in engineering design, Through the Operate phase of a field and on to eventual abandonment a system to address lessons and changes are noted with documents regularly updated ahead of additional drilling, field development, or abandonment activities.

The paper will present, and illustrate, the rationale adopted by BP showing examples of outputs produced along the process path, to demonstrate how the approach is delivered in practice.
A Dynamic Dual Gradient Model and its Use for Training Prior to DGD Operations in Norway and GoM
Authors: Svendsen Morten , Bjørkevoll Knut S. , Rommetveit Rolv , Aghito Manuel , Frøyen Johnny , Ødegård Sven Inge , Molde Dag Ove
Published: March 2015

A very realistic training simulator for dual gradient drilling has been developed, and then utilized for training. Realism in the responses that trainees see is ensured by embedding advanced real time downhole mathematical models, which are set up with the planned configuration for each upcoming well.

Dual Gradient Drilling (DGD) capabilities have been developed into an already proven dynamic hydraulic and temperature model. The flexibility of the model allows incorporating additional pumps in the flow, as in Dual Gradient Systems. The model includes dynamic 2-D temperature calculations, covering the radial area affecting the well. To create the Dual Gradient functionality a subsea pump module was developed, including the mud return line. To assure that the simulator behaves realistically extensive work was done, including implementation and verification of the U-tubing effects in the system. The model has been implemented into a virtual reality training simulator which also includes a full 3D topside drilling environment and 3D downhole visualization model.

This unique DGD training simulator has been utilized for training the drilling teams (both drilling team and DGD operational team). First training for operations utilizing the Controlled Mud Level (CML) system in Norway was developed around the training simulator. Then a further development was done prior to DGD operations in GoM, integrating a quick closing annular as well as booster line functionality. The training course was created around the Dual Gradient procedures, including the contingencies procedures with a focus on the communication between the different parties in the DGD operation.

The paper presents the model basis and how this is implemented into an advanced virtual reality training simulator which enable accurate modelling of the upcoming well. Furthermore, the training process of the drilling crews will be presented including lessons learned.
New Quantitative, Analytical Approach Provides Rapid Identification and Diagnosis of Dysfunctional Bit Performance
Authors: Rahmani Reza , Smith John Rogers
Published: March 2015

A complete analytical model for the penetration rate performance of polycrystalline diamond compact (PDC) bits has been developed to support a more rapid identification of drilling dysfunctions and allow more accurate efficiency calculations. The model predicts both rate of penetration (ROP) and torque based on the rock properties, pressure environment, PDC cutter and bit geometry, applied weight on bit (WOB), and rotary speed. The model has been used to identify and diagnose bit balling in full scale pressurized laboratory tests, as well as excessive drillstring torque and drag in the field.

Evidence of global bit balling and cutter balling was found in full-scale drilling tests in Catoosa and Mancos shales using both water base and oil base drilling fluids. Reduction in ROP with increasing WOB was confirmed as a symptom of severe balling, but typically time is required to identify the trend, at which point it is often too late, as severe bit balling is generally irreversible. The model was applied to identify global balling before the onset of irreversible global balling, using specific force ratio signatures. The symptoms were similar in both mud types and were observed to be completely reversible by a applying a timely adjustment of drilling parameters.

A sample application of the model to a southern U.S. shale play has been presented where both surface and downhole drilling measurements were used to evaluate the model. Overall, the model's predictions are in agreement with field data, as the model clearly identifies the occurrence of a dysfunction from change in formation properties and depth. The data also confirms that surface torque can be significantly different from downhole torque, though surface WOB is much closer to downhole WOB.

The proposed model can be used as a diagnostic tool for real-time monitoring of drilling efficiency to identify and diagnose dysfunctions. Because the prediction is based on applied WOB, which can be accurately measured in real time even from surface data, identification is faster than with torque-based equations such as mechanical specific energy (MSE). This provides the opportunity for the rapid mitigation of drilling dysfunctions and reduced ROP.
Well Cost Estimation and Control - Advanced Methodologies for Effective Well Cost Management
Authors: de Wardt John P , Peterson Susan K
Published: March 2015

Managers crave greater confidence in well construction costs, from the inception of a cost estimate for investment decisions, through cost estimation for budgeting, to cost tracking and control during well construction, and finally, for validity of performance tracking and benchmarking. Shortfalls in well cost estimation and control are due to three main sources: lack of defined processes, lack of discipline, and reliance on outdated or poor methodologies. This technical paper describes advanced methodologies for effective well cost management and documents their benefits to decision-makers and the industry. These include processes from the construction industry for cost tracking / control, best practices for estimating using probabilistic methods and leading to a process that can be applied for any well complexity utilizing modern methodologies. The technical content contributes directly to improved decision making by managers for investment in wells, improved planning for better decision making on choices for well design and drilling / completion operations including applications of various technologies, improved control of costs, and improved confidence that performance tracking and benchmarking are based on valid measures.
Assuring the Effectiveness of Well Engineering Operations Through a Company-Wide Internal Audit Process
Authors: Colt Alexandru , Thorogood John , Wirth Stefan
Published: March 2015

The effectiveness and impact of internal audit procedures implemented within an Operator’'s Well Engineering organization is described and how it ensures quality and integrity of the performance in the company’'s operating units. The work is based on four years of internal operations audit data where the results of operations audits have been analysed to identify trends in the levels of compliance and the quality of the technical work carried out in the different operations group.

It is explained how compliance with policies, procedures and standards is set and monitored within the Company and also show the effect of internal audit activities on performance. One of the outcomes of the audit process is the continuous refinement of the audit tools themselves. The audit results also highlight the need to review and refine the well delivery process itself and show correlation between audit results and operational performance. The results provide useful metrics and give an indication of the state of the health of the well engineering organisation.
Multiple Relief Well Planning for an HPHT Blowout in Southern Mexico
Authors: Varela Rodrigo , Iturrizaga Freddy , Patino Diego , Atencio Nixklafe , Romero Daniel , Buitrago Oscar , Pineda Javier
Published: March 2015

Following a catastrophic blowout incident onshore Southern Mexico on the Terra-123 well during due to an uncontrolled leak on the side valve of the wellhead, along with the loss of a barrier in the well, surface capping control operations and planning activities for three relief wells (RW) were initiated to intercept the target well (TW). This paper describes the planning and design process for the three RWs. The main objectives were set to intercept the target well and then killing it safely and efficiently.

The tasks performed for the relief operations included complete project management, well engineering, well bore positioning, communication protocols, hazard analysis and risk control (HARC), casing design, and hydraulic killing simulations.

Wellbore positioning was one of the main challenges due to the gross errors in survey data and local procedures, for this advanced geomagnetic referencing techniques were employed to identify the TW's position and design the RW's survey program. Active ranging techniques for well interception and detection were discarded due to salt interference; therefore, passive ranging and acoustic ranging (BARS: Borehole Acoustic Reflection Survey) techniques were selected as the best alternatives. Additional measurements while drilling (MWD) surface tests were performed to ensure the detection of the target casing. As part of the hydraulic communication design, tubing-conveyed perforating (TCP) was planned as the communication method.

All the RW trajectories were designed to accomplish the kill operation as standalone wells, meaning that the other two RWs are not needed if one is successful. A new casing design criterion to ensure low-risk scenarios during the interception and hydraulic communications was considered. Directional requirements based in the survey accuracy to determine the 3D relative positioning of the target well and RW were defined.
Innovative Fishbone SAGD Well Pair: An Integrated Approach to Efficiently Unlock the Resource Potential in Canadian Oil Sands Play
Authors: Ozdemirtas M. , McGinn T. , Mejia J. , McLennan R. , Lopez J.
Published: March 2015

The Surmont Project operated by ConocoPhillips with 50% partnership of Total E&P Canada is located in the Athabasca region of Northern Alberta. An in-situ thermal development method - Steam Assisted Gravity Drainage (SAGD) technology is used to extract the bitumen from the oil sand. Steam is injected into a horizontal injector well to heat up the bitumen so that it will flow with the support of gravity drainage and get produced from a horizontal well immediately below the injector (Butler 1991; Donnely 1997; Farouq 1997; Pirson et al. 1958). Surmont Phase 2 development consists of 11 pads each designed to accommodate 12 producer and injector wells. The full field design of 11 pads require a distance between lateral trajectories of one well pair and the build sections of wells on the other pad in order avoid the wellbore collision. Representing significant OOIP potential to the project, these buffer zones are larger than the average well spacing, but anticollision concerns with the drilling trajectories of the offsetting pads, do not allow for a regular SAGD well pair to be drilled into the zone. Through the multidisciplinary approach between joint venture partners, an innovative “Fishbone Infill Well Pair” concept was developed for the buffer zone between Pad #1 and Pad #5.

In the normal SAGD well pair design, the injector well lateral section is planned 5 meters vertically directly above the producer lateral section. In this case, due to the close proximity of the Pad #1 build sections, the fishbone injector lateral section was planned to be offset laterally a distance of 90 meters and a vertical distance of 21 meters to the fishbone producer well. The producer well, drilled under the build sections of Pad #5, has 6 fishbones which will establish the thermal connection with the injectors. The injector fishbone well, drilled over the built sections of Pad #5, was designed to have 2 fishbones towards producer well, and the toe of the main bore was directionally drilled towards the producer well. Significant anti-collision risks were minimized by utilizing active ranging technologies. All fishbones were sidetracked and drilled with a great success in the poorly consolidated McMurray oil sand formation. Special techniques were in place to avoid collapse risk in sidetrack junction points. Pre-selected fishbones both in producer and injector wells by subsurface team were lined with slotted liners. This paper focuses on the planning, design, drilling execution and lessons learned along the process of realization of this fishbone well pair, which is the first design of its kind in the Canadian oil sands.
Successful Use of Aluminum Drill Pipe with Steerable Mud Motors: Case Study in Shale Plays
Authors: Menand S. , Lehner Jeffry K. , Evans Nigel , Palmer Aaron , Metcalfe Arthur
Published: March 2015

High strength-to-weight aluminum alloy drill pipe is a powerful torque and drag reduction tool for deviated wells. The aluminum alloy drill pipe enables achieving strength to weigh ratios equivalent to 160 ksi yield strength steels and is typically 30-50% lighter than similar steel drill pipe. An operator has recently tested aluminum alloy drill pipe in a complex and highly deviated well profile.

This paper presents the key findings regarding the benefits of drilling using aluminum drill pipes in a mixed aluminum-steel string compared to a string using only steel pipes. Firstly, the innovative drill pipe design is presented, followed by lessons learned during rig operations regarding pipe handling practices, rig compatibility and pipe inspection. Then, the paper presents results of multiple advanced torque, drag and buckling simulations taking into account the rigorous mechanical characteristics of aluminum drill pipe. In the well planning phase, sensitivity analysis enabled optimisation of aluminum drill pipe placementalong the mixed aluminum-steel drill string according to the well profile and to predict anticipated torque, drag and loads on pipes while drilling. Through extensive modeling and field data interpretation, the paper presents a comparison of the overall drilling performances between steel only and aluminum-steel drill pipe strings and provides metrics in terms of torque and drag reduction. These results were then used to challenge horizontal and extended reach drilling well profiles where the utilization of only steel drill pipes has shown its limitation.
Deadman/Autoshear: Managing Precharge Pressure and Temperature Uncertainty
Authors: Cole Edward H.
Published: March 2015

As offshore drilling plans increase drill pipe sizes and push into deeper water, emergency accumulator systems for BOP control are also being pushed to maximum performance conditions. Recently some systems have failed subsea deadman/autoshear testing despite shore calculations that predicted they should work. Changing the accumulator precharge led to success in each case, but at the expense of costly stack pulls. This paper explores the causes of these failures and provides a new strategy to help prevent similar avoidable downtime events.

Optimization of subsea BOP lower stack deadman/autoshear accumulators should include consideration of temperature and pressure uncertainties that are inherent in the process of setting precharge pressure. For each well application, calculations typically compute an optimum precharge which provides the maximum usable fluid for the emergency function sequence. For single function sequences, this theoretically produces a subsea condition in which all of the fluid in the accumulators is usable. Precharge pressures below this optimum will provide more fluid, but the usable portion of this fluid gradually diminishes as precharge pressure is reduced. Precharge pressures above the optimum rapidly diminish the total amount of fluid (and thus usable fluid) in the accumulators. The usable volume penalty is therefore much higher for precharging above optimum than for precharging below optimum. As systems are pushed to maximum performance conditions, the margin between an optimum condition and a failing condition can be within normally accepted tolerances.

If temperature and pressure uncertainties involved in setting the precharge according to plan are considered, the most practical precharge plan will target slightly below the mathematical optimum. This will balance the asymmetric effects of uncertainties in the precharge settings. Correct calibration of the precharge pressure gauge and correct adjustments of precharge pressure for ambient temperature are both critical for reduction of precharge condition uncertainties. Adjustment of precharge to a specified plan is inherently difficult in practice for several reasons; therefore training of rig personnel and awareness of the effects of precharge condition uncertainty by planners on shore can prevent costly downtime.

In multi-function emergency sequences, accumulator precharge pressures are typically optimized to balance the needs of all functions. The same thought process described for single function sequences can be applied to multi-function sequences to keep the band of precharge uncertainty within the operating limits for all functions in the sequence.
Freeing Differential Stuck-Pipe with Nitrogen Reduces Significantly Lost-In-Hole Drill Strings
Authors: Heitmann Norbert , Burgos Elias Chamat
Published: March 2015

Terminally Differential Stuck Pipe accounts for more than 500 MIO USD/year of losses to the industry on Lost-In-Hole of Bottom Hole Drilling Assemblies (BHA) and consequential wellbore construction recovery work.

This document presents an innovative and rapid recovery solution to free terminally differential Stuck Pipe – to be applied when conventional freeing procedures are not available or insufficient, likely unsuccessful or have failed. This new method was recently applied in the Heavy Oil Faja Orinoco Belt, Venezuela, and saved several drill strings with MWD/LWD BHAs and averted wellbore loss of the openhole section drilled. The deployed Nitrogen assisted U-tubing process accomplishes the needed hydrostatic mud pressure reduction beyond currently available and generally applied procedures and sets new standards to recover from the all-times present Differential Stuck Pipe risks, when entering under-pressured permeable zones and depleted oil & gas reservoirs. This pioneering solution is rapid, requires only minimum standard pumping equipment, is in-expensive, is minimum invasive & disrupting, and is in conformance with industry set forth Well Control Standards.

An inter-active and integrated engineering tool kit (software) was developed to aid in the forces and pressure calculations and to model the required hydrostatic pressure reductions and fluid movements to lift-off the drill string, safe well control margins, drill string forces and for calculating the needed amount of Nitrogen - to lower sufficiently the hydrostatic pressure while retaining hole stability and well integrity within the safe working envelope.
Geo-Stopping Using Deep Directional Resistivity LWD: A New Method for Well Bore Placement Using Below-the-Bit Resistivity Mapping
Authors: Upchurch Eric R. , Saleem Saad , Russell Ken , Viandante Mauro G.
Published: March 2015

The Wheatstone LNG Project in Western Australia utilizes subsea big-bore gas wells for producing the Wheatstone and Iago gas accumulations. These wells employ a 9-5/8” production conduit from the top of the gas pay zone to gas the ocean floor to maximize their productive capacity. A critical design requirement is that the 9-5/8” production conduit must be set as close as possible to the gas pay zone (i.e., within 3m or less) without actually penetrating into the productive core of the gas zone. The wells must also intersect the horizontal top of the gas zone at inclinations (inc) of 45-60°. These design requirements impose a significant challenge to the efficient execution of a Wheatstone well. Traditional “ahead-of-the-bit” logging-while-drilling (LWD) solutions are capable of detecting resistivity fluctuations up to 1m in front of the drill bit. This, however, was considered an insufficient look-ahead distance to prevent premature penetration of the gas reservoir. Alternative solutions, such as pilot holes and biostratigraphic analysis of drilled cuttings, were also considered but found to be either too expensive and/or operationally impractical.

During an exhaustive search for a potential solution to this dilemma, the Wheatstone Project team reviewed a new Reservoir Mapping-While-Drilling technology being field tested1,2,3,5,7,8,9,10,11,12 for in-zone steering of horizontal wells and/or landing such wells at shallow angles of incidence relative to formation bedding (i.e., < 13°). That technology, based on Deep Directional Resistivity (DDR) technology, was recognized as a potential solution by the Wheatstone Project team – assuming it would work in an application for which it was neither designed nor intended (i.e., angles of incidence as high as 30-45°). Ultimately, the technology was successfully tested at Wheatstone, and is now the Project's default method for landing all big-bore gas wells to the exacting level of accuracy described above.

This paper details (1) the safety and well design drivers that precipitated the need for using DDR technology, (2) the physics and logic of this LWD system, (3) the new concept for applying the system in non-horizontal applications and (4) the observed results from the six wells that have, so far, been drilled at Wheatstone.
From Influx Management to Well Control; Revisiting the MPD Operations Matrix
Authors: Bacon William , Sugden Catherine , Gabaldon Oscar
Published: March 2015

Managed Pressures Drilling (MPD) offers the capability to detect very small influxes when compared to using conventional rig equipment. Furthermore, the potential exists to control and circulate out the influx with the MPD equipment, without shutting in and performing conventional well control. When executed appropriately, this approach to managing an influx represents a higher degree of safety and enormous cost savings. However, managing an influx with MPD, particularly when a subsea BOP is in place, is quite different to conventional well control. A critical part of implementing MPD is to ensure that there is a clearly defined procedure for determining when MPD influx management must cease, and well control be initiated.

A typical approach, regulated in some regions and voluntarily followed in others, is to create an MPD Operations Matrix before the operation begins, which outlines procedures that should be followed based on identifiable parameters following an influx. This matrix clearly identifies when it is appropriate to carry on with normal MPD operations, perform specific MPD influx control strategies, or shift to conventional well control. Forming the MPD Operations Matrix, however, can be challenging and has frequently been created inappropriately for the situations in which its use is intended. Development of a good understanding of how the well pressures and flow rates behave during MPD influx management is critical to ensuring a seamless handover between MPD influx management and Well Control.

In this work, extensive transient multiphase simulation is used to demonstrate the sensitivity of surface pressures to well, drilling and influx characteristics and their resulting importance in the development of an operations protocol. Particular attention is given to influx volume, intensity and dispersion within a water based drilling fluid. Also considered are multiple wellbore geometries with primary focus on deepwater applications, oil based drilling fluid, pump rate and drilling fluid density and rheology. Where possible, findings are validated using recorded field data.

This paper discusses and defines the transition between MPD influx management and conventional well control. The key parameters for calculating the boundaries of MPD influx management are determined and a protocol developed for smooth handover to well control operations. The protocol enables guidance to varying levels of influx management ranging from full influx detection and removal using the MPD equipment, to assisted shut in.
Trinexapac‐Ethyl Effects on Red Clover Seed Crops in Diverse Production Environments
Authors: Anderson N. P. , Monks D. P. , Chastain T. G. , Rolston M. P. , Garbacik C. J. , Ma Chun‐hui , Bell C. W.
Published: March 2015

Trinexapac‐ethyl (TE) plant growth regulator (PGR) effects on diploid red clover (Trifolium pratense L.) seed production were investigated in two diverse environments, Canterbury (CA), New Zealand (NZ), and Willamette Valley, Oregon (OR). Five TE rate (250 and 500 g a.i. ha−1) and timing [Biologische Bundesanstalt, Bundessortenamt, and CHemische Industrie (BBCH) growth stages 32, 51, 32 + 51] treatments and an untreated control were examined at six on‐farm sites in OR and one experimental site in CA in 2011 and 2012. Seed yield was increased across CA and OR production environments with 500 g ha−1 TE applied at BBCH 32 (15%, CA‐2011; 9%, OR‐2011; 13%, OR‐2012). Split applications of 500 g ha−1 TE (BBCH 32 + 51) improved seed yield by up to 13% in OR but had no effect in CA. Seed weight was generally inversely related to yield; TE treatments that produced the highest yield also had the lowest seed weight and thus did not contribute to TE‐induced yield improvement. Increases in inflorescences m−2 with TE ranged from 26 to 62% in all environments. Coupled with other measured effects of TE on flowering and stem production, these may have been contributing factors to seed yield enhancement by TE. Crop height was consistently reduced by TE across CA and OR environments but aboveground crop biomass was not affected by TE. The timely use of TE PGR is a practice that has broad applicability in red clover seed production across CA and OR environments.
Biomass Accumulation, Marketable Yield, and Quality of Atlantic Potato in Response to Nitrogen
Authors: Rens Libby R. , Zotarelli Lincoln , Cantliffe Daniel J. , Stoffella Peter J. , Gergela Douglas , Fourman Dana
Published: March 2015

Potato (Solanum tuberosumL.) in Florida is largely produced in sandy soils with low water and nutrient holding capacity, which makes N fertilizer timing and rate key factors for successful crop management. The objective of this study was to determine the effect of N fertilizer rate and application timing strategy on biomass accumulation, marketable yield, and tuber quality of chipping potato cultivar Atlantic produced in northeastern Florida. Field trials were conducted for three consecutive years on three commercial farms. All plots received 56 kg ha−1of N before potato planting. Nitrogen fertilizer treatments were 0, 56, 112, or 168 kg ha−1at plant emergence (Nemerg) combined with 56 or 112 kg ha−1of N applied as sidedress at tuber initiation (Ntuber init). Aboveground plant biomass showed no response to increasing N at Nemergor Ntuber init. Low yield and poor tuber quality were a result of intense rainfall patterns in the first year. For the other two seasons, marketable yield ranged from 28.7 to 36.1 Mg ha−1. Nitrogen treatments at emergence were not correlated to an increase in potato yield during the final 2 yr indicating that under the conditions of these experiments there was no N limitation. Total N applications over 280 kg ha−1did not increase yield or quality and Ntuber initabove 56 kg ha−1had no impact on plant biomass or tuber yield on any farm in any year of this study.
Planting Rate and Depth Effects on Tifton 85 Bermudagrass Establishment using Rhizomes
Authors: Baseggio Matheus , Newman Yoana , Sollenberger Lynn E. , Fraisse Clyde , Obreza Thomas
Published: March 2015

As with stolons, planting rate of rhizomes is important for successful establishment of cultivar Tifton 85 bermudagrass (Cynodon spp.). Planting depth is another aspect to be considered when establishing rhizomes in soils with low moisture retention. Shallow planting can increase sprouting and emergence; but if rhizomes are placed too shallow they may dry out without irrigation. The overall objective was to evaluate the effect of rhizome planting rate and depth on establishment success. Treatments were the factorial combinations of three planting rates (Low–2.6 m3 ha–1, Medium–5.2 m3 ha–1, and High–10.4 m3 ha–1) and two planting depths (6 and 12 cm). High planting rate increased Tifton 85 frequency, ground cover, and herbage dry matter (DM), independent of planting depth. In both years, the High rate resulted in 100% grass frequency and ground cover before 120 d after planting. Also, this treatment produced more than 2300 kg DM ha–1 in the establishment year, and this was greater than the Medium and Low rates (1230 and 900 kg ha–1, respectively) when planted at 6 cm, or than the Low rate planted at 12 cm (1430 kg ha–1). When using Low or Medium rates, planting at a 12‐cm depth, improved overall performance compared with 6 cm. Medium rhizome planting rate of ∼5 m3 ha–1 at a 12‐cm depth provided satisfactory ground cover and herbage DM at lower cost than High and thus is recommended for the sandy soils in the Suwanee River basin.
The relationship between chlorine consumption and trihalomethane formation from hydrophobic and transphilic fractions: a comparative study between two dams of east Algeria
Authors: Mellahi Dhaouadi , Zerdoumi Ridha , Rebbani Nacer , Gheid Abdelhak
Published: March 2015

In Algeria, the use of chlorine in drinking water treatment is a widespread practice. When chlorine combines with natural organic matter (NOM), it forms various chlorine by-products such as trihalomethanes (THMs). In this work, we studied the relationship between chlorine consumption and THM formation, by chlorination of hydrophobic and transphilic (TRS) fractions. We compared the kinetic behavior and the THM formation potential of two major dams in east Algeria. A nonlinear regression modeling study showed a good correlation of the specific chlorine consumption and the specific THM formation. In the case of Ain Zeda dam and at pH = 7, the specific THM yield coefficients αS were: 6.57 and 10.22 μg-THM/mg-Cl2.mg-C.L−1 for hydrophobic and TRS fractions, respectively, while at the same pH, they were 12.07 and 23.66 μg-THM/mg-Cl2.mg-C.L−1 for Ain Dalia dam. Although the NOM concentration of Ain Zeda dam was higher than that of Ain Dalia dam, the THM formation potential of Ain Dalia dam was greater than that of Ain Zeda dam. It seems clear that the water source origin and characteristics play a key role in this case. They affect the THM formation due to the complex composition of humic substances which differs from one source to another.
Treatment of domestic greywater by geotextile filter and intermittent sand filtration bioreactor
Authors: Charchalac Ochoa Sebastian Ignacio , Ushijima Ken , Hijikata Nowaki , Funamizu Naoyuki
Published: March 2015

Intermittent sand filtration (ISF) is an efficient system for treatment of greywater; however, the high quality of effluent and the simple set-up contrast with the high failure rate due to clogging of surface layers. The efficacy of several polypropylene non-woven geotextiles (apparent opening size from 0.10 to 0.18 mm) used as primary treatment filters to remove suspended particles from domestic greywater and the effects of this pretreatment in the performance of fine and small media size (0.3 and 0.6 mm) ISFs was examined. Results showed geotextile achieved suspended solids (SS) removal rates from 25 to 85% and chemical oxygen demand (COD) from 3 to 30%; although the portion larger than 75 μm was removed at higher rates (55–90%), particles smaller than the nominal pore size of the filter were also captured. Geotextile used as pretreatment resulted in improvement of lifetime of the ISFs over an experimental run of 60 days. The vertical profile of volatile organic matter in the ISFs was evaluated at the end of the experiment and it showed a clear reduction in the accumulation of organic material on the top layer of the ISFs, effectively avoiding its early failure by accumulation of solids.
Edge-texture 2D image quality metrics suitable for evaluation of image interpolation algorithms
Authors: Maksimovic-Moicevic Sanja , Lukac Zeljko , Temerinac Miodrag
Published: March 2015

A new objective, full-reference metrics of image quality is proposed in this
paper. It should match perceptual (subjective) image quality assessment in a
better way. The proposed method consists of two quality measures which
separately indicate image quality on edges and in texture areas which are
calculated in a three-step algorithm. The ?soft mask? is initially found for
separation in edge and texture areas. Then, two MSEs (mean square error) with
corresponding two PSNRs (peak signal-to-noise ratio) for edge and texture are
calculated using soft mask as the weighting factor. Finally, the obtained two
PSNRs are re-calculated into the two quality indices for edges and texture.
Additionally, the separation factor, defined as percentage of edge areas in
image, is considered, describing the influence of the image content on
perceptual assessment. The proposed 2D metrics is especially suited for
evaluations of different interpolation and compression algorithms.
Comments by the Auditing Standards Committee of the Auditing Section of the American Accounting Association on the IESBA ED Release (August 14, 2014), Proposed Changes to Certain Provisions of the Code Addressing the Long Association of Personnel with an Audit or Assurance Client
Authors: Gist Willie E. , Anderson Urton L. , Janvrin Diane J. , Pitman Marshall K.
Published: March 2015

On August 14, 2014 the International Ethics Standard Board for Accountants (IESBA) requested public comments to its Exposure Draft (ED) (IFAC 2014a) on proposed changes to the 2014 Code of Ethics for Professional Accountants (IFAC 2014b). The proposal aims to enhance the independence provisions of the Code to respond to threats that may be created by using the same audit firm personnel for audit or assurance engagements over an extended period of time. Among other things, the amendments would require (1) strengthened general provisions for all audits threatened by a long association of firm personnel, and (2) an increase in the mandatory “cooling-off” period, from two to five years, for the engagement partner on the audit of a public interest entity. The comment period ended November 12, 2014. This commentary summarizes the contributors' views on selected proposals in the ED.

Data Availability: The Exposure Draft and related request for specific comments are available at: http://www.ethicsboard.org. Paragraph referencing in the ED is extracted from the Code, set out in the 2014 Handbook of the Code of Ethics for Professional Accountants, available at: https://www.ifac.org/ethics/iesba-code/.
Diabetic Peripheral Neuropathy Compromises Balance During Daily Activities
Authors: Brown Steven J. , Handsaker Joseph C. , Bowling Frank L. , Boulton Andrew J.M. , Reeves Neil D.
Published: March 2015

OBJECTIVE

Patients with diabetes with peripheral neuropathy have a well-recognized increased risk of falls that may result in hospitalization. Therefore this study aimed to assess balance during the dynamic daily activities of walking on level ground and stair negotiation, where falls are most likely to occur.

RESEARCH DESIGN AND METHODS

Gait analysis during level walking and stair negotiation was performed in 22 patients with diabetic neuropathy (DPN), 39 patients with diabetes without neuropathy (D), and 28 nondiabetic control subjects (C) using a motion analysis system and embedded force plates in a staircase and level walkway. Balance was assessed by measuring the separation between the body center of mass and center of pressure during level walking, stair ascent, and stair descent.

RESULTS

DPN patients demonstrated greater (P < 0.05) maximum and range of separations of their center of mass from their center of pressure in the medial-lateral plane during stair descent, stair ascent, and level walking compared with the C group, as well as increased (P < 0.05) mean separation during level walking and stair ascent. The same group also demonstrated greater (P < 0.05) maximum anterior separations (toward the staircase) during stair ascent. No differences were observed in D patients.

CONCLUSIONS

Greater separations of the center of mass from the center of pressure present a greater challenge to balance. Therefore, the higher medial-lateral separations found in patients with DPN will require greater muscular demands to control upright posture. This may contribute to explaining why patients with DPN are more likely to fall, with the higher separations placing them at a higher risk of experiencing a sideways fall than nondiabetic control subjects.
Other-initiated repair across languages: towards a typology of conversational structures
Authors: Dingemanse Mark , Enfield N. J.
Published: March 2015

This special issue reports on a cross-linguistic study of other-initiated repair, a domain at the crossroads of language, mind, and social life. Other-initiated repair is part of a system of practices that people use to deal with problems of speaking, hearing and understanding. The contributions in this special issue describe the linguistic resources and interactional practices associated with other-initiated repair in ten different languages. Here we provide an overview of the research methods and the conceptual framework. The empirical base for the project consists of corpora of naturally occurring conversations, collected in fieldsites around the world. Methodologically, we combine qualitative analysis with a comparative-typological perspective, and we formulate principles for the cross-linguistic comparison of conversational structures. A key move, of broad relevance to pragmatic typology, is the recognition that formats for repair initiation form paradigm-like systems that are ultimately language-specific, and that comparison is best done at the level of the constitutive properties of these formats. These properties can be functional (concerning aspects of linguistic formatting) as well as sequential (concerning aspects of the interactional environment). We show how functional and sequential aspects of conversational structure can capture patterns of commonality and diversity in conversational structures within and across languages.
Surgical Outcomes of Primary and Revision Augmentation Rhinoplasty using a Processed Fascia Lata
Authors: Kim Yoo Suk , Park Do Yang , Shin Dong Hyun , Yang Seok Min , Seong Sang Yeob , Yoon Joo-Heon , Kim Chang-Hoon
Published: March 2015

Background

Dorsal augmentation is the most commonly performed procedure in rhinoplasty for Asian patients. Due to the anatomic features of the Asian nose, the use of nonautologous materials to obtain a proper degree of augmentation is inevitable in most cases. Because the use of nonautologous materials possesses a higher risk of complications, surgeons are concerned about selecting suitable materials for the procedure, especially in revision rhinoplasty. Therefore, this study was designed to evaluate the suitability and usefulness of a homologous material, Tutoplast-processed fascia lata (TPFL), in revision augmentation rhinoplasty.

Methods

Retrospective analysis of 104 rhinoplasty patients (primary, 86; revision, 18) who had undergone dorsal augmentation using TPFL was conducted. The comparison of surgical outcomes between primary and revision surgery was made using objective [dorsal height (DH) and radix height (RH), complication rate] and subjective (patient satisfaction) parameters.

Results

The degree of augmentation represented by DHand RH was comparable between primary and revision rhinoplasty using TPFL. In comparing the rate of postoperative complications, only minor incidents were noted, in six cases after primary surgery and in one case after revision surgery. Patient satisfaction was measured in both primary and revision augmentation, with a significant difference observed between the two groups (40.57 ∓ 9.25 versus 31.48 ∓ 7.59; p < 0.05).

Conclusion

TPFL is a feasible implant material that delivers suitable augmentation and patient satisfaction with minimal morbidity in both primary and revision rhinoplasty.
Systematic Review and Metaanalysis of Middle Meatal Packing after Endoscopic Sinus Surgery
Authors: Hobson Candace E. , Choby Garret W. , Wang Eric W. , Morton Sally C. , Lee Stella
Published: March 2015

Objective

The objective of this systematic review was to evaluate synechiae formation in patients who underwent packing in the middle meatus at the completion of endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) or recurrent acute rhinosinusitis.

Data Sources

PubMed and Ovid.

Review Methods

Prospective randomized controlled studies of ESS with the placement of middle meatal packing were reviewed and included for analysis. Metaanalysis of the pooled data was performed.

Results

Eighteen prospective, randomized, controlled trials met inclusion criteria, resulting in a total of 925 subjects. Although there was a trend toward decreased risk of synechiae formation in the patients who underwent placement of middle meatal packing postoperatively (RR = 0.544), this did not achieve statistical significance on metaanalysis (p = 0.052).

Conclusions

This systematic review and metaanalysis suggests that use of middle meatal packing does not significantly reduce the risk of synechiae formation after ESS. There was, however, significant heterogeneity of the data analyzed, and the difference between groups was just short of statistical significance in our metaanalysis. Additional prospective randomized studies on this topic will further elucidate the utility of middle meatal packing.
Superoxide Dismutase Reduces the Inflammatory Response to Aspergillus and Alternaria in Human Sinonasal Epithelial Cells Derived from Patients with Chronic Rhinosinusitis
Authors: Lawrence Lauren A. , Mulligan Jennifer K. , Roach Catherine , Pasquini Whitney N. , Soler Zachary M. , Banglawala Sarfaraz M. , Karnezis Tom T. , Gudis David A. , Schlosser Rodney J.
Published: March 2015

Background

Aspergillus fumigatus and Alternaría alternata are ubiquitous environmental fungal allergens that can exacerbate airway inflammation and contribute to the disease process in patients with chronic rhinosinusitis (CRS). These antigens have been shown to induce human sinonasal epithelial cells (HSNECs) to promote a proinflammatory response, but what is unclear is a means by which to reduce these effects. Inhaled pathogens can induce HSNECs to produce reactive oxygen species (ROS) that trigger cytokine production.

Objective

This study aimed to determine whether the free radical scavenger superoxide dismutase (SOD) could reduce HSNEC-derived inflammation, as measured by interleukin (IL)-6 and IL-8 production, in response to Aspergillus or Alternaria exposure.

Methods

Sinus tissue explants were collected at the time of surgery from control patients (n = 7) and patients with CRS with nasal polyps (CRSwNP) (n = 9). HSNECs were cultured from the explants and treated with Aspergillus, Aternaria, and SOD for 24 hours. Cell supernatants and lysates were collected, and IL-6 and IL-8 concentrations were measured using enzyme-linked immunosorbent assay.

Results

In control and CRSwNP HSNECs, Aspergillus and Aternaria both increased cytokine production (p < 0.05), as measured by IL-6 and IL-8 concentration. SOD treatment reduced the inflammatory response to fungal antigen exposure from CRSwNP HSNECs but not control HSNECs. In CRSwNP patients, SOD significantly decreased IL-6 and IL-8 production after Alternaria exposure and IL-8 after Aspergillus exposure (p < 0.05).

Conclusions

When HSNECs from CRSwNP patients are treated with SOD concurrently with Aspergillus or Alternaria, SOD treatment decreases the fungal antigen-induced inflammatory response. The ability to attenuate inflammation induced by common fungal allergens with SOD treatment could provide a novel therapeutic or preventative approach for patients with CRS or other allergic inflammatory airway diseases.
Moving the Goods: Performance Measures and the Value Proposition for Transportation Projects
Authors: Schofer Joseph L.
Published: March 2015

This paper addresses the challenges of implementing transportation projects and policies. Despite advances in data, analysis tools, and technologies, the difficulty of making the case remains for transportation actions where the values of those actions are perceived by key stakeholders as less than commensurate with the costs that they are asked to pay. This perceived inequity occurs when citizens who bear the impacts of transportation actions are not the beneficiaries, when the benefits are characterized in aggregate, and when projects do not appear to be salient to the majority of stakeholders. In such cases, there is a need to construct a more explicit value proposition, a statement of promised results that fosters belief on the part of stakeholders. Promised results should be presented in credible forecasts of outcomes from actions that improve transportation performance. They should be described in terms that are specific enough to address the what's-in-it-for-me question. And they should be built on agency credibility earned by a record of delivering results. Freight projects are particularly difficult to advance because the economic and social benefits of freight performance are largely invisible to citizens, underscoring the need to make the value proposition for freight project outcomes relevant to individuals and communities. The relationships between transportation investments and their outcomes, the quality of forecasting tools, and the credibility of transportation agencies can be advanced through systematic, balanced, post-project audits (including before–after evaluations) to learn and to demonstrate the actualized value of transportation projects and policies. These ideas are entirely consistent with, and supportive of, the concepts of performance-based management advanced under MAP-21.