bluuebunny/crossref_metadata_2025 huggingface dataset:
Mensa Field, Deepwater Gulf of Mexico (GOM) - Case Study
Authors: Razi Muhammad , Bilinski Peter
Published: October 2012

Mensa, Mississippi Canyon Block 731, is a deepwater GOM subsea Geo-pressured gas field, producing from an upper Miocene; proximal lobate turbidite sheet sand associated with a faulted four-way closure. Reservoir structure is a nearly flat, covering some 5000 acres at depths of 15200 to 15,800 feet subsea. Net pay is as high as 170ft, average porosity 30% and permeability up to 1 Darcy.

Mensa Field is connected to platform via a +60miles subsea flow line. The field came on production in 1997 and rates peaked at 300 MMSCF/D during early life, with current rates ~27 MMSCF/D. As of Dec 2011 the field had produced 850 BCF gas. The field is producing by a combination of gas expansion, moderate water drive and compaction. Original reservoir pressure was 10,100 psi declining to 7,100 psi. Mensa field indicate presence of three distinct and unique pressure trends have occurred during field life.

The early life trend is related to the original development wells. During this time period pressures fell sharply, performing as a (dominantly) depletion drive reservoir. The trend indicates presence of isolated compartment(s). After a few years of production pressures leveled off significantly. The shift from early life trend to mid life trend is sharp and distinct. It seems reservoir became in contact with (originally) isolated gas compartment(s) and aquifer. History match (Material Balance and Reservoir Simulation Models) is achieved by establishing communication between main tank and (originally) isolated gas and aquifer (by breaking barriers). The late life pressure trend (occurred in the last few years) indicate that aquifer influx has effectively blocked the main producing wells from a significant gas area and pressure support. Recent pressure recorded in watered out zone is stabilized at ~7,100 psi.

The depositional setting for the "I" gas sand appears to be a lobate fan system associated with a turbidite basin entry -point. Based upon well and seismic data it can be subdivided into two shingled lobate deposits, oriented northwest to southeast and referred to as the "Ia" and "Ib". Seismic loop architecture suggests that the aquifer may also be composed of shingled lobate deposits. The "Ia" is the younger deposit and covers the northern portion of the field. It is probably completely filled with gas and is either shaled or eroded out before reaching the assumed GWC structural level at 15,775ft SS. The older "Ib" covers the southern half of the field and has GWC. The lobes are high net to gross (> 90%) but contain very thin shale and other low permeability layers sometimes correlative between wells. The low permeability rock was not a barrier to gas flow as proved by a 2006 well test that penetrated swept (wet) "Ib" sand in a low structural reservoir position. In contrast, the combination of shingled lobate geometries and the aforementioned poor quality rock layers have proven to be a significant baffle to both higher pressure aquifer support and to water influx.
Understanding "SRV": A Numerical Investigation of "Wet" vs. "Dry" Microseismicity during Hydraulic Fracturing
Authors: Nagel Neal B. , Garcia Xavier , Sanchez Nagel Marisela , Lee Byungtark
Published: October 2012

Effective monitoring of hydraulic fracturing stimulations is critical to their optimization, and the evaluation of field microseismic data is now commonly used in many of the active shale plays for this purpose. The concept of Stimulated Reservoir Volume (SRV), for example, is a common technique wherein the extent of the microseismic data is used to represent the size of the fluid drainage area for a fracture or well. A principal challenge with the interpretation of microseismic data - and its use to determine drainage area or some other metric for the success of the stimulation - is the understanding of the actual cause of the microseismicity itself. Basic geomechanics principles show that rock failure - the cause of microseismicity - is a result of changes in the in-situ effective stresses relative to a given rock strength. Effective stress - which is the stress acting on the rock matrix - may change either through a change in pore pressure (leading to ‘wet’ microseismicity) or through a change in the total stress (leading to ‘dry’ microseismicity). Dry microseismicity may occur well beyond the pressure field and be hydraulically disconnected from the wellbore. In this paper, we present the results of a numerical study of hydraulic fracturing-induced microseismicity using a discrete element code, where the mechanical behavior of the natural fractures is modeled explicitly, which allows for the quantitative evaluation of ‘wet’ versus ‘dry’ microseismicity.
Structural Controls on Vertical Growth of Hydraulic Fractures as Revealed Through Seismic Moment Tensor Inversion Analysis
Authors: Baig Adam M. , Urbancic Ted I.
Published: October 2012

Completion designs for hydraulic stimulation of shale-gas reservoirs frequently accounts for vertical growth of the treatment volume in the formation. Where vertical growth is expected, wells are drilled near the base of the reservoir optimizing the distribution of proppant upwards. Other treatments may seek to transport treatment fluid across a lithologic barrier, effectively trying to "treat two formations for the price of one." Vertical growth needs to occur under controlled conditions, undesirable growth leads to a potential creation of pathways for treatment fluids to leak out of formation, or worse pathways allowing undesirable fluids to flow into formation. In either case, this could lead to a loss in optimization for production. To better understand vertical growth characteristics of hydraulic treatment volumes, microseismic monitoring arrays deployed downhole just above the formation provide a good discriminant for vertical growth of events. Further characterization of this growth can be accomplished through Seismic Moment Tensor Inversion (SMTI), when a sufficient angular distribution of multiple downhole arrays detects the microseismicity. SMTI can distinguish the source type of the mechanisms (e.g. openings, closures, shear, etc.) and the orientations of the activated structures, allowing for a more complete picture of the failure process. In the example provided, different stages of stimulation in the Marcellus shale formation are examined in the context of varying degrees of vertical growth. When vertical growth occurs, as identified through SMTI analysis, it appears to be related to the activation of sub-vertical natural joints whereas for vertically confined stages the primary fracture set is subhorizontal suggesting delamination of fissile bedding planes is the dominant process. These differences, from stages in the same completion program, suggest that subtle background stress changes can result in very different behaviors. Full understanding of these mechanisms will lead to further optimization of these treatment programs to promote vertical growth to traverse structural barriers and retain containment of the treatment within zone.
Application and Evaluation of Eulerian-Granular Approach for Characterization of Sand Erosion in Multiphase Flows
Authors: Lu Yaojun , Agrawal Madhusuden
Published: October 2012

This paper presents a novel approach for characterizing erosion wear in multiphase flow systems; it is based on Eulerian- Granular theorem rather than the conventional Eulerian-Lagrangian methodology. The first step in the novel approach is to characterize multiphase distribution based on the multi-fluid concept, which treats both the carrying fluid and entrained particles as continuous phases. The second step is to quantify the impinging velocity of particles using the granular model, which introduces particle-particle interaction and turbulence modification to carrying fluids beyond the fluid-particle and particle-fluid coupling considered in the Eulerian-Lagrangian approach. The final step is to determine the erosion rate by applying more representative particle velocity into a selected erosion correlation. In comparison to the Eulerian-Lagrangian approach, the Eulerian-Granular approach is able provide more realistic prediction on erosion profile in full particle loading range due to the least assumptions.
Poroviscoelastic Modeling of Time-Dependent Wellbore Closure when Drilling Anisotropic Gas Shale and Oil Shale Reservoirs - Applications in the Haynesville Shale and the Colony Pilot Mine Shale
Authors: Hoang Son K. , Abousleiman Younane N. , Hemphill Terry
Published: October 2012

The creep and relaxation characteristics of gas and oil shale create unique challenges to the characterization, modeling, and production from these unconventional reservoirs. Notable problems include modeling of stress relaxation and stress inhomogeneity during reservoir deformation, wellbore closure during and after drilling, reduction of brittle hydraulic fracture initiation and growth, and closure of hydraulic fracture and proppant embedment after stimulation. Moreover, the mineral structure and composition in addition to the extremely fine lamination and depositional modes forming the thin beddings in gas and oil shale creates geomechanical transversely isotropic behavior observable from the nano scale to the macro scale and adds further complexity to these problems. In this study, the effects of shale rock viscoelasticity, induced pore pressure, and shale rock anisotropy on time-dependent wellbore deformation and contraction during and after drilling were investigated using a fully-coupled geomechanics (poromechanics) approach. The complex interplay between time-dependent rock deformation and pore fluid pressure buildup and diffusion processes was explicitly modeled within the realm of poroviscoelasticity. Studies on the Haynesville Shale and the Colony Pilot Mine Shale have also been carried out using material parameters determined from laboratory creep tests. It was found that the viscoelasticity of the rock matrix controls not only the final magnitude but also the rate of wellbore closure during and after drilling. Moreover, the transversely isotropic nature of the reservoir shale must be accounted for in the estimation of wellbore wall displacement. The common assumption of material isotropy for traditional reservoirs led to severe errors in the estimation of the magnitude as well as the rate of wellbore contraction.
Surfactant Enhanced Oil Recovery from Naturally Fractured Reservoirs
Authors: Lu Jun , Goudarzi Ali , Chen Peila , Kim Do Hoon , Britton Christopher , Delshad Mojdeh , Mohanty Kishore K. , Weerasooriya Upali P. , Pope Gary A.
Published: October 2012

Large volumes of oil remain in naturally fractured carbonate oil reservoirs and water floods are often very inefficient because many of these reservoirs are mixed-wet or oil-wet as well as extremely heterogeneous. Naturally fractured reservoirs are challenging targets for chemical flooding because they typically have a high permeability contrast between the fractures and the matrix with low to extremely low matrix permeability. In addition, some of the world's largest oil reservoirs are fractured carbonates with high reservoir temperature and high salinity formation brine and some of them also have low API gravity oils, which also increases the difficulty of recovering the oil. We have developed a stable surfactant that shows promising results even when all of these conditions are present at the same time. Both static and dynamic imbibition experiments were done using a fractured carbonate core. These results were interpreted using a mechanistic chemical reservoir simulator.
Effect of Nanoparticles on Flow Alteration during CO2 Injection
Authors: Aminzadeh B. , DiCarlo D. A. , Chung D. H. , Kianinejad A. , Bryant S. L. , Huh C.
Published: October 2012

Surface-treated nanoparticles have been shown to stabilize CO2-in-water foam by adhering to the surface of CO2 bubbles and preventing their coalescence. However, to bring the nanoparticles from the bulk phase to CO2/water interface requires an input of mechanical energy. Co-injection of CO2 and an aqueous dispersion of nanoparticles at high rates is known to provide sufficient energy. However, this co-injection is less favorable because of the operational constraint, i.e., injectivity reduction. Here, we show that beneficial effect of nanoparticles, manifested as improved sweep efficiency, occurs even at low shear rates in a drainage displacement.

We inject high-pressure liquid CO2 into sandstone cores initially saturated with brine containing suspended nanoparticles and compare the results with the case with no nanoparticle addition. The water saturation distribution was measured using CT scanning techniques. The results show that the nanoparticles increase sweep efficiency and reduce the gravity override compared to displacements without nanoparticles. The new mechanism described here provides a promising alternative for mobility control in CO2 floods.
Analysis of Hydraulic-Jet Lift System application on Wells in the North Region Assets, AIPRA and AIATG (Case study)
Authors: Granados J. , Mancilla S. F.
Published: October 2012

Hydraulic-Jet (HJ) lift system field tests were performed in wells of "Activo Integral Poza Rica-Altamira" (AIPRA) and "Activo Integral Aceite Terciario del Golfo" (AIATG) assets in North Region of "Petroleos Mexicanos-E&P" (PEP). Results are analyzed in this case study, which includes background, objectives and scope, overview on HJ theoretical frame, tests results, a brief technical and cost analysis, conclusions and recommendations.

Part of technological challenges in oil fields exploitation, are those associated to wells without own enough energy to flow from the bottom hole to the surface facilities. This condition occurs in most of the wells of AIPRA and AIATG assets, becoming Artificial Lift Systems (ALSs) a strategic issue essential to achieve production goals and mandatory topic subject to permanent analysis and evaluation.

Operative continuity during observed periods of the HJ tests, support technical feasibility for wells in AIPRA and AIATG, with low incidence of failure, rapid restarting of the system, as well as few associated workover; and consequently low delayed production because of these reasons. Furthermore, HJ potential to fulfill key advantages was observed, among them: feasibility and speed of running and retrieving without workover rig, in situ production measurement feasibility, low flow rates achievement feasibility, and, in AIATG case, capacity as a centralized system in multi-well locations. For these cases, these circumstances are considered as "breaking paradigms" for hydraulic lifting as a system only applicable to wells of relative high productivity. Achieved results support economic feasibility of the Hydraulic-Jet lift system in the two assets, even evident marginal profit for AIATG case, where reduce costs because encompasses integral systems for several wells in the same location is an option.

Based on previous experiences, it has been observed that, the more suppliers petroleum market incorporate, the more opportunities to lower costs come to pass until "real costs" are achieved. Hence, it is recommended to involve new suppliers as a strategy to promote competitiveness.
Compositional Controls on Mudrock Pore-Size Distribution: An Example from Niobrara Formation
Authors: Kuila U. , Prasad M. , Derkowski A. , McCarty D. K.
Published: October 2012

Speculation exists about the presence of micropore and mesopore networks either exclusively within the organic matter or as pore systems in the inorganic components. This study presents a comparison of pore-size distributions (PSD) in a set of fine grained rocks from the Niobrara Formation using a combination of meticulous, precise, and repeatable laboratory preparation and measurement techniques. The analyses were performed on aliquot samples of ground powders (<0.4 mm) following rigorous procedures of homogenization and division (splitting) to obtain mineralogically and chemically equivalent portions for each analysis. The mesopore and micropore distribution was measured by conventional subcritical N2 gas-adsorption analysis at 77.3 K. These results, combined with quantitative mineral analysis by XRD and organic content and maturity measurements, indicate that the abundance of illite-smectite group clay controls the small scale pore features in the Niobrara Formation. The samples show a characteristic 3 nm pore-size distribution peak that correlates strongly with clay abundance, but not with organic content. The low thermal maturity of the organic matter (OM) further implies the lack of associated small pores. Instead, this non-porous OM hinders access to the fine mesopore structure of the clay aggregates.
The Development of Organic Porosity in the Woodford Shale Related To Thermal Maturity
Authors: Curtis M. E. , Cardott B. J. , Sondergeld C. H. , Rai C. S.
Published: October 2012

Since the discovery of pores in the organic matter of gas shales, the conventional thought has been that the pores formed as a result of hydrocarbon generation during the thermal maturation of the organic matter. However, thermal maturity alone may not be the only factor in determining the formation and preservation of pores in the organic matter. In this paper we report on a study of organic porosity in Woodford Shale samples with vitrinite reflectances ranging from 0.51% Ro to 6.36% Ro. Using focused ion beam (FIB) milling and scanning electron microscopy (SEM), it is observed that while the first appearance of porosity for the samples occurs by 1.23% Ro, there are anomalies. One anomaly is the complete lack of organic porosity in the 2.00% Ro sample. In addition, some samples with a vitrinite reflectance ≥ 1.23% Ro exhibit regions of porous organic matter adjacent to non-porous organic matter regions that are separated by a few microns Observations show that while some regions of porous organic matter appear protected by grains others appear stress-supporting. These observations have important consequences for using indicators such as thermal maturity in predicting the occurrence of pores in the organic matter of shales.
Ceramic Sand Screens for Sand Control in Unconsolidated Reservoirs: Application and Sand Retention Capabilities in the Maturing Oil Field, Gaiselberg, Austria
Authors: Wildhack S. , Lesniak C. , Müssig S. , Strahammer F. , Leitner M.
Published: October 2012

The oil production in Zistersdorf, Austria operated by the Rohölaufsuchungs AG (RAG) has a long history beginning with the first completion in 1937, and a variety of production technologies were applied. The reservoirs here are primarily of Sarmatian sand stones showing good compaction and permeability in lower zones but highly unconsolidated sands and serious sand production in upper formations.

The sands in these upper layers are poorly sorted, so it is difficult to realize sand control. In the past, sand production has been handled by metal wire wrap screens combined with gravel packing. Large amounts of finer particles, however, made it necessary to downsize the slot openings in order to protect pumps and jewelry. In consequence, the wells experienced an increase in pressure drop over the screens and the gravel packing, in some cases resulting into production losses of up to 50%.

With the newly developed stand-alone ceramic sand screens, this disadvantage could be eliminated, and sand control in the unconsolidated formations was successfully proven in the Gaiselberg 16 well.

This paper will present the design of the applied ceramic screen, its deployment underneath the downhole pump and the production data of Gaiselberg 16. The evaluation of productions rates, pressure drops and sand measurements will be discussed and compared with performed sand retention testing. The paper will give an interpretation of the sand retention mechanisms of the ceramic sand screen and its capability to assist the building up of a natural formed gravel pack.
A Robust Optimization Tool Based on Stochastic Optimization Methods for Waterflooding Project
Authors: Ambia Fajril
Published: October 2012

The increasing demand of crude oil has led to the increasing needs to improve recovery. Waterflooding is one of the most common secondary recovery techniques applied to many reservoirs. The method of waterflooding is to inject water into the reservoir to maintain reservoir pressure. In general, the determination of well locations is structured to form certain pattern (e.g. five spot). However, it is not the only factor affecting the optimum configuration. Besides reservoir rocks, fluid characteristics and well configurations, injection and production strategies (e.g. rates or bottom hole pressures) can also significantly affecting the overall recovery.

As reported by other researchers, due to the complex nature of reservoir characterizations and fluid properties, the optimization solution of those parameters tends to have many best possible solutions. Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) were chosen because their robustness to avoid local optima and finding the global optima of an objective function. The objective function used to drive the solutions were Recovery Factor (RF) and Net Present Value (NPV) of a waterflooding project.

An Optimization tool, (OpTool) was developed to prove that stochastic optimization methods could fit best in optimizing the waterflooding project. This tool is capable to communicate with reservoir simulators with known input/output formats to populate cases that would be evaluated using the well-defined objective functions. A synthetic case was built to show the OpTool capabilities to tackle waterflooding optimization problems. This tool is capable to determine an optimum pattern design (e.g. well spacing) and production and injection strategy to maximizing the RF and NPV of the project.
Effects of Dissolution on the Permeability and Porosity of Limestone and Dolomite in High Pressure CO2/water Systems
Authors: de Freitas Filho Ricardo D.
Published: October 2012

During water-alternating gas (WAG) and others processes involving CO2 injection, interactions between the acid brine and reservoir rock take place, promoting changes in reservoir characteristics. In carbonate reservoirs, these interactions may cause rock dissolution due to acid solution-carbonate reaction. The understanding of these interactions impacts strongly on enhanced oil recovery (EOR) projects using CO2, as well as on the capture and sequestration of CO2 in the reservoir rock as an alternative way to storage of greenhouse gases. This study is dedicated to investigate experimentally interactions between CO2, water and carbonate rock. Experiments involved saturating dolomite and limestone samples by carbonated water under pressures up to 10,000psi in a high-pressure vessel. The vessel was then kept closed for 240h at steps of 48h. At each step, porosity, permeability and mass of the rock were determined. X-ray tomography was carried out for every sample. Analysis of the water composition with regard to the salinity was also made. There were measurable changes in mass, porosity and permeability. Porosity and permeability changes produced improvements or damages on the flow properties, which is related to the fine grains produced during the dissolution process leading to the partial blockage of porous media. Mass reduction was up to 0.95 % and 0.35%, respectively for limestone and dolomite. Permeability varied +/−60% (dolomite) and up to 86% (limestone). Porosity varied +/−3% for dolomite and +/−20% for limestone. The results show that dissolution should be considered in the projects and operations of CO2 injection processes, mainly WAG and carbonated water, which produces acid aqueous solutions able to react to the carbonate rock and causes continuous changes on the rock properties and consequently the oil production system.
Prediction of Barite Sag in Horizontal Annular Flow
Authors: Hashemian Yahya
Published: October 2012

Under certain drilling conditions, the weighting material particles such as barite can settle out of the drilling fluid. This phenomenon, known as barite sag, can lead to a number of drilling problems including lost circulation, well control difficulties, poor cement job, and stuck pipe. This study investigates barite sag, both experimentally and numerically, in the annulus under flow conditions.

Experimental work has been conducted on a large flow loop to investigate the effects of major drilling parameters on barite sag by measuring the circulating fluid density. Results of the tests indicate that the highest sag occurs at low annular velocities and rotational speed and also at high inclination angles. It was observed that at inclination angles less than 60°, for any annular velocity, barite sag is not significant. Eccentricity of a non-rotating inner pipe did not have a significant effect on barite sag. However, effects of inner pipe rotation on barite sag for an eccentric annulus are more significant than concentric case.

The simulation part of this study is based on a proposed particle tracking method called "Particle Elimination Technique". The traveling path of each solid particle is assumed to be a function of size and shape of the particle, fluid velocity and rheology. Based on the estimated traveling path of particles, density of the fluid is updated considering the number of particles whose paths lead to the bottom of the annulus and become motionless. In order to capture the complexities associated with the solid-liquid flow, a lift force is assigned to the solid particles that enable adjustment of the model with experimental results.

Comparing the results of numerical simulation to the experimental study on the effects of annular velocity on barite sag in a horizontal annulus shows a good agreement. The numerical simulation was modified from laboratory scale to real wellbore dimensions for practical drilling applications. Results of the simulation show prediction of the density of the drilling fluid in the horizontal section of a wellbore with various lengths and dimensions under different annular velocities.
Predictive functional control of temperature in a pharmaceutical hybrid nonlinear batch reactor
Authors: Stampar Simon , Sokolic Sasa , Karer Gorazd
Published: October 2012

These days, in times of recession, we are forced by competitiveness and the
optimization of production to lower the costs of the temperature control in
pharmaceutical batch reactors and increase the quantity and quality of the
produced pharmaceutical product (active pharmaceutical substances).
Therefore, a control algorithm is needed which provides us rapid and precise
temperature control. This paper deals with the development of a control
algorithm, where two predictive functional controllers are connected in a
cascade for heating and cooling the content of the hybrid batch reactor. The
algorithm has to be designed to cope with the constraints and the mixed
discrete and continuous nature of the process of heating and cooling. The
main goal of the control law is to achieve rapid and exact tracking of the
reference temperature, good disturbance rejection and, in particular, a small
number of heating and cooling medium switchings. The simulation results of
the proposed algorithm give us much better performance compared to a
conventional cascade PI algorithm.
The effects of supplementing diet with bacillus cereus on performance and carcass yield of broilers
Authors: Radakovic Radomir , Baltic Milan , Sinovec Zlatan
Published: October 2012

The aim of this study was to examine alternative substances which could have the capability to replace antimicrobial growth promoters in feed for broilers. The 42-day long trial was performed on 100 days-old Arbor Acres broilers divided into two groups. Both groups of broilers were offerred a commercial feed mixture, while Paciflor C.10 ? (Hoechst - Intervet) was added in the amount of 0,10 and 0,05 kg/t of starter and finisher feed for the second group. Paciflor ? contains Bacillus cereus IP 5832 in the amount of 1010 CFU/g. Broilers of the control group had an average daily gain (ADG) of 48,86?6,80 g and a feed:gain ratio (FGR) of 2,17 kg with carcass yield of 72,2 %. The inclusion of direct-fed microbials (DFM) significantly increased ADG by 1,59 % and imporoved FGR and carcass yield by 1,84 and 0,42 % respectively. It is interesting to underline that supplementing the diet with DFM had only mild positive effects on ADG in the first two phases while a stronger influence was expressed on FGR. Better efficiency is probably due not only to the healthier composition of gut microflora, but to longer microvilli of the gut epithelium with consequently improved resorption of nutrients. The obtained results suggest that direct-fed microbials have the potential to replace, at least to a certaint antibiotics as feed additives.
Diagnosis of hoof disease in horses using computed tomography
Authors: Kovac Milomir , Nowak Michael , Kaufels Nikola , Tambur Zoran
Published: October 2012

This study describes findings of computed tomography investigations at the Bergische Equine Clinic (Germany) of 39 horses with hoof diseaseas. The most frequently findings were the navicular syndrome (eight horses), laminitis (seven horses), keratnoma (six horses) and ossification of collateral cartilages in the distal phalanx (four horses). The special value of the computed tomography is in evaluating the size and courses fracture/fissure of the navicular and koffin bones, which were diagnose in five horses. In four of horses no pathologic changes of the hoof were determined by computed tomography.
Complementary Evaluation: The Development of a Conceptual Framework to Integrate External and Internal Evaluation in the New Zealand School Context
Authors: Mutch Carol
Published: October 2012

One of the themes of current school evaluation research and debate is the extent to which it is possible to integrate internal and external evaluation and accountability and improvement. In this article, the author outlines how New Zealand has attempted to reconcile these differing perspectives and aims. New Zealand has a national system of school evaluation which has been in place since the education reforms of the 1980s. The Education Review Office (ERO) evaluates the quality of education in all pre-tertiary educational institutions and services. The ERO has adapted its approach over the years as it has been subject to external review, as government priorities have changed and as the process has become embedded in regular school planning and evaluation cycles. The ERO's current strategic focus is on building schools' confidence and competence in conducting self-evaluation as part of an ongoing focus on continuous improvement. This article reports on the iterative development of the Building Capacity in Evaluation (BCiE) project, with particular reference to developing the underpinning conceptual framework – complementary evaluation. The framework aims to bring together the strengths of internal and external evaluation and the ERO's focus on school accountability and improvement in a complementary manner.
Two Decades of Behavioral Research on Analytical Procedures: What Have We Learned?
Authors: Messier William F. , Simon Chad A. , Smith Jason L.
Published: October 2012

This paper presents a comprehensive review of behavioral research on external auditors' use of analytical procedures published over the past two decades. We frame our review around four phases of the analytical procedures process: develop an expectation, establish a tolerable difference, compare the expectation to the recorded amount and investigate significant differences, and evaluate explanations and corroborative evidence. We find that while considerable research has focused on auditors' performance of the latter phases of the analytical procedures process (i.e., investigate significant differences and evaluate explanations and evidence), relatively less research has focused on the initial phases of the process (i.e., setting expectations and establishing thresholds). We also find that prior research has primarily focused on the preliminary and substantive analytical procedure settings with little research examining auditors' judgments and decisions when using analytical procedures at the overall review stage of the audit engagement. Finally, we summarize the significant findings from research in each phase and provide a number of research questions whose answers could improve our understanding and the performance of analytical procedures.

Data Availability: All articles are publicly available.
Effect of canopy openness on the pressure of predatory arthropods and birds on epigeic insects
Authors: Šipoš Jan , Drozdová Michaela , Drozd Pavel
Published: October 2012

As canopy structure produces spatial heterogeneity of litter microclimatic conditions and thus is a crucial factor affecting ground insects, we hypothesized that low canopy openness has a positive effect on the activity of ground insect predators in forest and non-forest habitats. Blowfly larvae were used as bait along the canopy openness gradient (forest interior, forest edge, base of a solitary tree and meadow) and the attack rate was assessed after 30 min of exposure. Although the predation rate has a varying pattern throughout the year in different habitats, in contrast to previous studies, we observed a significant positive trend in predation rates toward the forest interior. A significant trend in predation rate was not observed in non-forest areas. We found that the trend was strongly influenced by ants as the most active taxon of predators (65%) attacking our baits, whereas ground beetles, the second-most active predators (21%), showed the opposite trend along the canopy openness gradient.
In vitro growth of some species of Ascochyta Lib.
Authors: Kosiada Tomasz
Published: October 2012

Fungi from the genus Ascochyta are generally facultative saprotrophs, which cause diseases in both monocots and dicots. Over 1 000 species belonging to this genus have been identified, 18 of which infect monocot plants from the family Poaceae. This study analyses the effects of temperature and light on the growth of selected fungi which infect monocots (A. agrostidis, A. avenae, A. brachypodii, A. desmazieri, A. digraphidis, A. ducis-aprutii, A. festucae, A. graminea, A. hordei, A. hordei var. americana, A. hordei var. europea, A. hordei var. hordei, A. melicae, A. phleina, A. skagwayensis, A. sorghi, A. stipae, A. zeicola), grown on three types of media; Potato Dextrose Agar (PDA), Coon’s agar (CN) and oatmeal agar (OMA). The fastest growth among the analyzed fungi at low temperatures was found in Ascochyta melicae, while at high temperatures it was A. zeicola. The fastest in vitro growth (average of all fungi) was observed on CN medium at 20°C (3.4 mm/day), while the lowest on OM medium at 5°C (1.0 mm/day). Radial mycelial growth in dark and the light conditions varied. On average, all isolates grew faster in the dark (3.1 mm/day) than in the light (1.9 mm/day). The greatest effect on the production of pycnidia was found for the isolates. Variation in growth and production of pycnidia depended on temperature, medium and lighting for fungi from the genus Ascochyta infecting monocots. Such variation indicates a potential occurrence of these fungi in different environments.
Protective effects of glucosamine-kynurenic acid after compression-induced spinal cord injury in the rat
Authors: Korimová Andrea , Cížková Dáša , Toldi Jozsef , Vécsei László , Vanický Ivo
Published: October 2012

Kynurenic acid (KYNA), a metabolite of the essential amino acid L-tryptophan, is a broad spectrum antagonist of excitatory amino acid receptors, which have also anticonvulsant and neuroprotective properties. After spinal cord injury (SCI), excitotoxicity is considered to play a significant role in the processes of secondary tissue destruction in both grey and white matter of the spinal cord. In this study, we have tested the potential therapeutic effect of glucosamine-kynurenic acid, administered after experimental compression-induced SCI in the rat. Spinal application of glucosamine-kynurenic acid continually for 24 hr after experimental SCI resulted in improved motor function recovery, beginning from the first week of evaluation and continuing until the end of the study (4 weeks). After 4 weeks’ survival, quantitative morphometric analysis of the spinal cord showed that glucosamine-kynurenic acid treatment was associated with improved tissue preservation at the lesion site. These findings indicate that spinal application of glucosaminekynurenic acid is neuroprotective and improves the outcome even when administered after spinal trauma. Our results suggest that the treatments initiated in early posttraumatic period can alleviate secondary injury and improve the final outcome after SCI.
Cantor extension of an abelian lattice ordered group equipped with a weak relatively uniform convergence
Authors: Jakubík Ján , Černák Štefan
Published: October 2012

The notion of weak relatively uniform convergence (wru-convergence, for short) on an abelian lattice ordered group G has been investigated in a previous authors’ article. In the present paper we deal with Cantor extension of G and completion of G with respect to a wru-convergence on G.
Residual finiteness, subgroup separability and conjugacy separability of certain HNN extensions
Authors: Wong K. , Wong P.
Published: October 2012

In this note we shall give characterisations for HNN extensions of non-cyclic polycyclic-by-finite groups with normal infinite cyclic associated subgroups to be residually finite, subgroup separable and conjugacy separable.
Basic matrix theorems for $\mathcal{I}$-convergence in (ℓ)-groups
Authors: Boccuto A. , Dimitriou X. , Papanastassiou N.
Published: October 2012

Some aspects of the theory of order and (D)-convergence in (ℓ)-groups with respect to ideals are investigated. Moreover some new Basic Matrix Theorems are proved.
Existence of homoclinic solutions for a class of second-order non-autonomous Hamiltonian systems
Authors: Zhang Qiongfen , Tang X.
Published: October 2012

By using the variant version of Mountain Pass Theorem, the existence of homoclinic solutions for a class of second-order Hamiltonian systems is obtained. The result obtained generalizes and improves some known works.
Existence and uniqueness of mild solution for fractional integrodifferential equations of neutral type with nonlocal conditions
Authors: Li Fang
Published: October 2012

In this paper, we prove the existence and uniqueness of mild solution of a class of nonlinear fractional integrodifferential equations of neutral type with nonlocal conditions in a Banach space. New results are obtained by fixed point theorem.
The Spirit of Potentials: An Interview with Bretta Gerecke
Authors: Pearce Wes D.
Published: October 2012

Wes D. Pearce talks to award-winning and Siminovitch nominee Bretta Gerecke about her design process when working on productions for Edmonton's Catalyst Theatre. The discussion focuses on how the highly original costumes were imagined and then “conjured into being” for the theatre's celebrated “cautionary Gothic monster trilogy”: Frankenstein (2006), Nevermore (2009), and Hunchback (2011). Given the extraordinarily collaborative process that is the basis for all productions at Catalyst Theatre the interview then moves on to discussing how Gerecke has made the successful transition designing for opera, which is not historically know for its collaborative nature.
François Barbeau: An Inspiration to Costume Designers
Authors: Lemieux Andrée
Published: October 2012

During the 11th edition of the Prague Quadrennial of Performance Art and Space, APASQ paid tribute to François Barbeau, Canadian costume designer. During his long and prolific career, Barbeau has designed for all eras and addressed all genres, from the simplest to the most eccentric. This article presents his vision of theatre costumes and his research on materials. His collaboration with Cirque du Soleil enabled him to further his research on sublimation printing, both in the shows Dralion and Wintuk and as consulting designer with the research laboratory integrated into the Direction des unités de création costumes et accessoires (DUCCA). The article also explains the choices that guided scenographer Louise Campeau and guest curator Andrée Lemieux in organizing the exhibition presented in Canada's kiosk at the 2011 Quadrennial.
François Barbeau: Research on Materials
Authors: Barbeau François
Published: October 2012

François Barbeau with Louise Campeau and Andrée Lemieux present his exploration and creation of designerly languages for the costumes for Cirque du Soleil.
Environmentally Conscious Highway Design for Crest Vertical Curves
Authors: Ko Myunghoon , Lord Dominique , Zietsman Josias
Published: October 2012

The primary objective of this study was to provide guidelines and tools for quantifying the environmental impacts in terms of fuel consumption and emissions of various highway geometric design conditions related to crest vertical curves. Second-by-second speed profiles were generated with speed prediction and polynomial models, and fuel consumption and emission rates based on vehicle-specific power and speed were extracted with the recently developed motor vehicle emission simulator (MOVES) modeling software. The generated speed profiles were matched with the extracted rates and aggregated during a trip on the curves. A benefit–cost analysis was also carried out with existing data from Washington State. The results demonstrated that the design vehicle respectively consumed and produced 10% less fuel and carbon dioxide on the crest vertical curve designed with a rate 1.5 times greater than the minimum rate of the vertical curvature documented in the AASHTO Green Book. For other emissions—carbon monoxide, oxides of nitrogen, hydrocarbons, and particulate matter of 2.5 μm or less—there were also reductions by up to 31% on the curve. The results also showed that the environmental economic benefits from flattening the curve design exceeded additional construction costs for a 30-year design period. Vertical curve design providing a flattened curvature can be environmentally and economically beneficial throughout the life of the highway. This study shows the efficacy of environmentally friendly design for sustainable transportation.
Analysis of Emissions at Congested and Uncongested Intersections with Motor Vehicle Emission Simulation 2010
Authors: Papson Andrew , Hartley Seth , Kuo Kai-Ling
Published: October 2012

The motor vehicle emission simulator (MOVES) modeling software of the U.S. Environmental Protection Agency enables researchers and practitioners to model vehicle emissions at the project level. With this tool, agencies can identify and evaluate the effectiveness of local traffic control strategies to reduce emissions at project hot spots, such as congested intersections. This study analyzes vehicle emissions at congested and uncongested signalized intersections under three traffic intersection scenarios, ranging from Level of Service (LOS) B to LOS E. Emissions are much less sensitive to congestion than control delay. A shift in operation from LOS E to LOS B reduced per vehicle nitrogen oxide emissions by 15% and particulate matter emissions by 17%, while control delay decreased by 40%. The largest sources of emissions were cruising and acceleration; they accounted for more than 80% of total emissions under all scenarios. Idling accounted for less than 18% of all intersection emissions. This analysis calculates emissions with a time-in-mode methodology that combines emission factors for each activity mode (i.e., acceleration, deceleration, cruise, idle) with a calculation of the total vehicle time spent in that mode. This approach demonstrates the contribution of each activity mode to intersection emissions and suggests opportunities for control strategies with the potential to affect intersection emissions. The streamlined methodology may be a helpful tool for agencies that are interested in analyzing project-level emissions and control strategies, but lack staff resources or expertise for microsimulation-based scenario analysis.
Basal melting at the Ekström Ice Shelf, Antarctica, estimated from mass flux divergence
Authors: Neckel Niklas , Drews Reinhard , Rack Wolfgang , Steinhage Daniel
Published: October 2012

We characterize the basal mass balance of the Ekström Ice Shelf, Dronning Maud Land, Antarctica, using interferometrically derived surface velocities and ice thickness measurements from radio-echo sounding (RES). The surface velocities are based on data from European Remote-sensing Satellites-1 and -2 (ERS-1/2) during 1994–97. The ice thickness grid consists of 136 RES profiles acquired between 1996 and 2006. Mass fluxes are calculated along selected RES profiles where possible, to reduce uncertainties from ice thickness interpolation. Elsewhere large-scale mass fluxes are calculated using interpolated ice thickness data. Themass flux into the Ekström Ice Shelf from the main grounded drainage basins is estimated to be 3.19±0.4Gt a–1. The mass flux near the ice shelf front is 2.67±0.3Gt a–1. Assuming steady state, and based on the equation of continuity, we interpret the residual mass flux as a combined effect of snow accumulation and subglacial melting/refreezing. Using net snow accumulation rates from previous studies, we link the mass flux divergence in irregular-shaped polygons to processes beneath the ice shelf. The highest subglacial melt rates of ~1.1ma–1 are found near the grounding zone of two main inflow glaciers, and around the German station Neumayer III. The detection of unlikely refreezing in a small area ~15 km west of Neumayer III is attributed to both dataset inaccuracies and a (possibly past) violation of the steady-state assumption. In general, the method and input data allow mapping of the spatial distribution of basal melting and the results are in good agreement with several previous studies.
Value addition in vegetables production, processing and export from Bangladesh
Authors: Hoq MS , Raha SK , Sultana N
Published: October 2012

Bangladesh has immense prospect for exporting vegetables to the world market and it has also produced high quality exportable fresh vegetable. Although the share of export earning in vegetables increasing day by day but export is constrained by several issues. Thus the present study was undertaken to determine the value addition, cost and return of vegetables production and export at different levels and also suggest some policy implication for improving the present system. The study was based on both primary and secondary data. The sample included vegetables producer, suppliers, and exporters. Vegetable producers and suppliers were selected from Ulokhola of Kaligonj Upazila and exporters were selected from Dhaka city (Motijheel, Kakrail, Shantinagar, Khilgaon, and Sham Bazar).Appling conventional profitability analysis the study revealed that per hectare production cost for cowpea, snake gourd, and bitter gourd were estimated at Tk. 73838, Tk.72,029 and Tk.1,04,644 respectively and value addition for cowpea, snakegroud, and bitter gourd were calculated at Tk.86,162, Tk.1,52,611 and Tk.2,37,356 respectively by farmers. The average estimated marketing costs incurred by suppliers were Tk.2906 per ton. The value addition by suppliers were Tk.3094 per ton. The average estimated marketing cost incurred by different exporters for UK, Saudi Arabia, Kuwait, and Qatar were Tk.1,69,442, Tk.98,429, Tk.1,03,499, and Tk.85,324 per ton, respectively. The value addition by different exporters for UK, Saudi Arabia, Kuwait, and Qatar were Tk.55,778, Tk.16,661, Tk.16,902, and Tk. 23,754 per ton respectively. Among all the cost items, airfreight charge was the highest. It was revealed from the study that bitter gourd cultivation is more profitable and BCR is also highest (3.27) and UK market was more profitable for vegetables export. Bangladesh J. Agril. Res. 37(3): 377-388, September 2012 DOI: http://dx.doi.org/10.3329/bjar.v37i3.12081