bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Surrogate Reservoir Model (SRM) to an Onshore Green Field in Saudi Arabia; Case Study
Authors: Mohaghegh Shahab D. , Liu Jim , Gaskari Razi , Maysami Mohammad , Olukoko Olugbenga A.
Published: February 2012

Application of the Surrogate Reservoir Model (SRM) to an onshore green field in Saudi Arabia is the subject of this paper. SRM is a recently introduced technology that is used to tap into the unrealized potential of the reservoir simulation models. High computational cost and long processing time of reservoir simulation models limit our ability to perform comprehensive sensitivity analysis, quantify uncertainties and risks associated with the geologic and operational parameters or to evaluate a large set of scenarios for development of green fields. SRM accurately replicates the results of a numerical simulation model with very low computational cost and low turnaround period and allows for extended study of reservoir behavior and potentials. SRM represents the application of artificial intelligence and data mining to reservoir simulation and modeling.

In this paper, development and the results of the SRM for an onshore green field in Saudi Arabia is presented. A reservoir simulation model has been developed for this green field using Saudi Aramco's in-house POWERS™ simulator. The geological model that serves as the foundation of the simulation model is developed using an analogy that incorporates limited measured data augmented with information from similar fields producing from the same formations. The reservoir simulation model consists of 1.4 million active grid blocks, including 40 vertical production wells and 22 vertical water injection wells.

Steps involved in developing the SRM are identifying the number of runs that are required for the development of the SRM, making the runs, extracting static and dynamic data from the simulation runs to develop the necessary spatio-temporal dataset, identifying the key performance indicators (KPIs) that rank the influence of different reservoir characteristics on the oil and gas production in the field, training and matching the results of the simulation model, and finally validating the performance of the SRM using a blind simulation run.

SRM for this reservoir is then used to perform sensitivity analysis as well as quantification of uncertainties associated with the geological model. These analyses that require thousands of simulation runs were performed using the SRM in minutes.
Performance Enhancements in Metal-Crosslinked Fracturing Fluid
Authors: Kalgaonkar Rajendra , Patil Prajakta
Published: February 2012

Hydraulic fracturing employs crosslinked polymeric gels that are pumped into a subterranean formation with sufficient viscosity properties to generate fracture geometry in the subterranean rock and transport solid proppants to hold the fracture open. The extent of crosslinking a polymeric gel can significantly contribute to success or failure of a fracturing treatment. Crosslinking agents used in commercial fracturing applications include borate, titanium, and zirconium (Zr) complex ions.

As fracturing fluid is pumped downhole, it experiences different shears, such as high shear caused by tubulars and low shear in the fracture. Typically, polymeric gels are shear-thinning and will reduce in viscosity on application of high shear. The fracturing fluid's inability to shear-recover as it transitions from a high-shear regime in tubulars to a low-shear regime as it enters the fracture will lead to compromising of near-wellbore (NWB) proppant transport, and treatment can screenout. Borate crosslinkers that are known to provide the shear-recovery property to the fracturing gel typically have a temperature limitation of 300°F. Conversely, metal crosslinkers that have good temperature stability beyond 300°F are prone to irreversible shear degradation as the fluid passes from the high-shear to a low-shear regime, thus compromising efficient proppant transportation inside the fracture.

This paper presents the development of a novel shear-stable fracturing fluid for high-temperature applications. Rheological characterization was performed with a Fann Model 50-type viscometer at temperatures greater than 300°F using typical wellbore shear rates including shear-history profiles. The fluid chemistry of a Zr crosslinker and buffer combination that controls the crosslinker kinetics to yield shear-resilient and shear-recoverable viscoelastic gel after passing through the shear-history profile is presented. Additionally presented are regained permeability results obtained using conventional breakers that demonstrated the frac fluid's cleanup property.
Including the Effect of Capillary Pressure to Estimate Critical Rate in Water Coning Well
Authors: Ling Kegang , Shen Zheng
Published: February 2012

For oil reservoir with bottom water and/or gas cap, gas and water conings impose serious problems during the oil production. Coning leads to the premature gas and water breakthrough thus results in high water cut and gas oil ratio, which require a higher surface facility capacity to process excessively produced water and larger three-phase separators to separate gas, oil, and water. Consequences of early breakthrough are large footprint due to large facility, more energy to operate field, and low oil recovery. Even though numerous studies had been focused on solving the critical oil rate for gas and water coning problems, to our knowledge none of them considers the effect of capillary pressure on critical oil rate. The ignorance of capillary pressure caused the error of calculated critical rate to rise to 300%, according to the real field case study.

The errors caused by neglecting capillary pressure are severe in low permeability reservoirs. For the purpose of good production design, we investigated the effect of capillary pressure on critical rate estimation. Our study showed that the calculated critical rates are close to real field critical rates. The existing methods underestimate the critical rate by not taking capillary pressure into account. Therefore, more accurate critical rates can be obtained using our method. With more accurate result more reliable production plan can be designed to maximize the ultimate recovery.
The Key of Success to Manage Shallow Heavy Oil and Unconsolidated Sand Reservoir
Authors: Rizkallah M.. , Kamal S.. , Hassan W.. , Mamdouh M.. , Taha A.. , Khaled M.. , Hassan I.. , Waly H.. , Tag A..
Published: February 2012

Heavy oil is an unconventional oil resource that is characterized by high viscosities and high densities compared to conventional oil. Most heavy oil reservoirs are deposit in shallow depths.

Issaran oil field is located 290 KM southeast of Cairo and 3KM inland from the western shore of the Gulf of Suez covering 20,000 acres. The field was discovered on 1981. The Zeit Sand formation in Issaran is highly unconsolidated sandstone. The oil is 10-12 API. The top of reservoir depth is around 700-800 ft, the thickness is around 15 ft. The initial reservoir pressure and temperature are 250 psi and 90°F respectively. The oil viscosity is more than 4000 cp at standard conditions and the reservoir rock is oil wet with 5-10% H2S content. The highly unconsolidated nature of the sand and the thin pay (heat losses) makes the economical production of Zeit Sand very challenging.

The OOIP in the developed area is estimates at around 2.5 MMSTB with estimated 35 % recovery factor using steam injection. The productivity of the wells initially before steaming is very low and the average cold production per well was below 5-10 BOPD.

In 2009 Scimitar initiated a reservoir simulation to study the optimum development scenario in term of wells spacing and injection/production scheme. The model assumed there is no aquifer existing (as per G&G interpretation). As of Dec. 2009, it was decided to develop the area based on 150 mt spacing (18 new wells were drilled and 9 old wells have been re-completed in Zeit sand.

This project faced a lot of challenge to produce Zeit sand formation either by cyclic steam stimulation or by steam flooding injection in the gas cap or oil leg wells, this paper will illustrate the different phases of this project and the challenges that were faced to complete the wells and handle the unconsolidated sand problem. Every effort was made to keep the cumulative voidage replacement ratio around one and the ultimate steam oil ratio below five which will have adequate reflect on the economics of the projects.
Diminishing the Gap between Mathematics and at Present Reservoir Simulators towards A Next Generation Simulator: A Strategic Approach
Authors: Jha Ashutosh Kumar , Bansal Gopal , Sangwai Jitendra
Published: February 2012

In a present scenario the applications of numerical reservoir simulators are very wide and extensive. Simulation is the only tool to describe quantitatively multi-phase flow in a heterogeneous reservoir. But, nowadays most of the users of reservoir simulators are becoming the hostages of computer-generated results, even though, many incorrect analysis techniques, mathematical models and computational approaches are used extensively in reservoir simulation study. This paper reveals such incorrect but commonly accepted approaches and presents alternate and correct mathematical approaches for the advancement of new generation reservoir simulators.

Firstly, wide literature survey is done and presented to show the mathematical approaches that are applied presently to the simulators. Then various examples (e.g. fracture and shale flow solutions where fine mesh discretization technique may lead to erroneous results due to singular velocities at the fracture and shale tips, fracture flow modeling using discrete point source which is replaced by continuous line source, etc.) of incorrect models are shown and proved to be the source of erroneous results and numerical instability.

After revealing such incorrect models, the solutions for eliminating this incorrect techniques and models are presented and proved numerically and analytically. Mathematical techniques and formulations used in this paper are advanced conformal mapping, streamfunction and streamline tracing, modern singular integral equation approaches, moving boundary value problems technique, artificial viscosity analysis, generalization of coordinate system, curvilinear grid generation, integral transformations, etc. which stabilize the mentioned simulation models.

In recent years the technological innovations in drilling and production and complicated reservoir studies have challenged the existing simulators so is the key target of this paper is to move in direction of the next generation simulators that can solve the various mentioned inaccuracies. Various accurate mesh generation algorithms are developed in this paper to revolutionize the modern petroleum engineering.
Optimization of SAGD in Conductive Fractured Reservoir
Authors: Fattahi A.. , Zare A. R. , Akhondzadeh H.. , Derahman M. N. , Yunan M. H.
Published: February 2012

Steam Assisted Gravity Drainage is a successful process that has been applied to extract heavy oil and bitumen mostly in Canada. Conductive fractures as reservoir heterogeneity are spaced a few meters from each other and differ from network fractures. There are a few studies investigating the impact of such fractures on SAGD performance. This work is a numerical study examining the relative location and configuration of wells to conductive fractures as an attempt to optimize SAGD process in three types of conductive fractures including horizontal, vertical and oriented fractures.

While vertical fractures located above the well pair enhance the oil recovery rate at early time, those located far from the well pair do not affect the process performance. Consequently, to optimize the process, the wells should be applied beneath the vertical fracture. For the vertical conductive fractures locating at bottom of the reservoir, higher well spacing results in more desirable performance if the wells are drilled at the place of the fracture. Sensitivity analysis of injector-producer well spacing illustrated that for horizontal fractures locating around 5 m from the reservoir base, the injector should be drilled above the fracture to enhance the process performance much more than the case of having the injection well below the fracture. Also it is showed that the well pair should be located in a manner that oriented fractures with positive slope place at right hand side and near the wells. Moreover, Off-setting the wells in the fracture direction resulted in enhanced behavior of the process. In low permeability tar sands, hydraulic fracturing can mimic vertical conductive fractures which improve steam chamber expansion, hence resulting in better performance. This study suggests some screening criteria for the well placement design to enhance the oil recovery in conductive fractured reservoirs.
Fast and Efficient Assisted History Matching for Large-Scale Applications
Authors: Friedel Torsten , Taware Satyajit
Published: February 2012

History matching is a key task for field reviews. Over the past decades, assisted history matching techniques have effectively automated parts of the process. Methods commonly applied include genetic algorithms, adjoint methods, ensemble Kalman filters, streamline-based inversion, and conventional Newton-type methods. All these methods, however, are numerically expensive, often to a prohibitive degree for large and complex reservoirs.

A novel method aims to overcome this limitation. It combines the advantages of two well-established technologies: a numerically efficient Newton-type optimization scheme and full-physics proxy-type modeling using grid coarsening. It focuses on unknowns that can be readily re-parameterized, such as relative permeability and capillary pressure functions, fluid and rock properties, or fluid contacts. In addition, the statistical analysis of the parameter identification allows the establishment of confidence intervals, parameter correlations, and sensitivities.

Newton-type optimization methods can numerically be less expensive and potentially show superior convergence behavior under certain conditions. Although they are prone to converge to local minima and are less suitable for adjusting permeability or porosity distributions, they can be advantageous for smaller parameter spaces when using a re-parameterization approach. At the same time, grid coarsening allows drastically reduced runtimes while maintaining realistic geological and physical assumptions. Using the Newton-type calibration technique, the workflow suggested comprises initial screening, ranking of parameter sensitivities, and subsequent detailed parameter calibration to obtain the optimal parameter set.

A large reservoir dataset in which simulation runtimes would not allow for traditional assisted history matching approaches shows the advantages of the novel method. Convergence is rapid and minimal time is required to optimize sets of relative permeabilities, including endpoints and curvature of each individual function. As illustrated, the re-parameterization also allows imposition of a physically sensible solution. Most importantly, the statistical analysis of the results identifies key sensitivities in the reservoir, ultimately contributing to a better understanding of data gaps and uncertainties.
Occurrence, Character and Origin Of Natural Gases In The Deepwater Nile Delta, Egypt
Authors: Nassar Marawan , Nijenhuis Ivar , Fattah Tharwat Abdel , Ramadan Alaa Eldin
Published: February 2012

The offshore Nile Delta is an established and significant gas and condensate province in North Africa. It is considered to have significant remaining hydrocarbon potential for future exploration. The main petroleum system comprises of an Oligocene Type II/III mixed oil and gas prone source rock which charges the overlying thick sequence of Neogene-Quaternary clastics. While the hydrocarbon potential of the Nile Delta and its geological and stratigraphic pattern has been the focus of numerous studies, the origin of the gas and associated fluids has been poorly documented.

In order to characterize the natural gas at the study area, an integrated geological, geophysical and geochemical study was performed on 439 gas samples and 493 cutting samples collected from 7 wells in addition to a review of published work covering the origin of natural gas and associated fluids.

The analysis shows that the gases are dominated by methane (97%-100%) and the light carbon isotopic composition (δ13C1) values (−57.4‰ to −80‰) suggest that these gases are derived from the decomposition of immature (0.3-0.6 Ro%) sedimentary organic matter by Methanogens activity under relatively low temperatures (<80°C).

The paper will give an overview of the integrated work, focusing on the geochemical analysis used to describe the occurrence and character of the natural gases in the study area.
Figured World of Eating Disorders: Occupations of Illness
Authors: Elliot Michelle L.
Published: February 2012

Background. The biomedical diagnosis of eating disorders signifies a mental illness with complex physical symptomology. The socio-cultural determinants and impact of eating disorders on daily occupations are not adequately addressed in this classification.

Purpose. This paper introduces the concept of a figured world as a framework for how eating disorders exist in daily activity and social discourse. How occupations become ascribed with meaning generated by an eating disorder will be proposed through the voice of a composite character in the figured world.

Key Issues. Central elements to contextualizing figured worlds include positional identity, self-authoring, and semiotic mediation. The generation of meaning in illness arises from the integration of these elements into this specific figured world.

Implications. The competing agendas of the biomedical model and figured world permit a new understanding of the challenges associated with recovery. For occupational therapists, these challenges require the reattribution of meaning of daily occupations.
La participation des aînés à des activités de bénévolat: Une revue systématique
Authors: Godbout Elisabeth , Filiatrault Johanne , Plante Michelle
Published: February 2012

Contexte. Le bénévolat peut représenter une forme de participation sociale à la fois très significative pour les aînés et bénéfique pour leur santé, tant sur les plans physique que psychologique. C'est pourquoi les ergothérapeutes et les autres professionnels de la santé, de même que les intervenants du milieu communautaire soucieux de favoriser le vieillissement en santé, font de plus en plus appel à des aînés bénévoles pour collaborer aux initiatives de promotion de la santé et de soutien à la communauté. Toutefois, ils font souvent face aux défis que posent le recrutement de bénévoles et le maintien de l'engagement bénévole.

Objectif. Une revue systématique des écrits a été réalisée afin d'éclairer les pratiques dans ce domaine. L'objectif était d'identifier les facteurs influençant la participation des aînés à des activités de bénévolat.

Méthodologie. Six bases de données bibliographiques ont été interrogées à l'aide de mots clés.

Résultats. Au total, 27 articles ont été retenus pour l'analyse et ont permis de dégager une série de facteurs susceptibles d'influencer la participation bénévole, soit des facteurs liés à la personne, à l'environnement et à l'occupation.

Conséquences. Des pistes concrètes pour faciliter le recrutement des aînés et le maintien de leur participation à des activités de bénévolat découlent de la présente analyse.
Partnering for Change: An Innovative School-Based Occupational Therapy Service Delivery Model for Children with Developmental Coordination Disorder
Authors: Missiuna Cheryl A. , Pollock Nancy A. , Levac Danielle E. , Campbell Wenonah N. , Whalen Sandra D. Sahagian , Bennett Sheila M. , Hecimovich Catherine A. , Gaines B. Robin , Cairney John , Russell Dianne J.
Published: February 2012

Background. Developmental coordination disorder (DCD) is a common, chronic health condition that is poorly recognized and understood in school settings. Without appropriate support, children with DCD are at increased risk of depression, decreased fitness, and obesity. Evidence shows that occupational therapy intervention needs to shift from remediation of impairment to chronic disease management.

Purpose. This paper describes Partnering for Change (P4C), an innovative, empirically derived school health service delivery model for children with DCD.

Key Issues. The model emphasizes the partnership of the occupational therapist with educators and parents to change the life and daily environment of a child. The P4C partnership focuses on capacity building through collaboration and coaching in context. The model uses a tiered approach which includes whole class instruction, dynamic performance analysis, and monitoring response to intervention.

Implications. P4C is a model that responds to the needs of this population, addresses issues identified in research, and provides a continuum of services designed to build capacity.
Sensory Processing and ADHD in children with Fetal Alcohol Spectrum Disorder
Authors: Abele-Webster Lynne A. , Magill-Evans Joyce E. , Pei Jacqueline R.
Published: February 2012

Background. Sensory processing problems are prevalent in children who have fetal alcohol spectrum disorder. It is unclear to what degree these problems are distinct from attention deficits as measured during the diagnostic process in these children.

Purpose. To understand sensory processing in these children, which may assist with early identification and intervention.

Method. The relationship between attention and sensory processing was studied in a retrospective sample of 26 Canadian children diagnosed with fetal alcohol spectrum disorder.

Findings. A very low correlation (r = .02) between Short Sensory Profile scores and the attention deficit hyperactivity index of the Conners' Parent Rating Scales was found for the five- to ten-year-old children. Sensory processing problems were found in 81% of the children, similar to other studies of children with fetal alcohol spectrum disorder.

Implications. These findings can guide modifications of the environments, tasks, and approaches to children with fetal alcohol spectrum disorder.
Asymptotic analysis of the Nörlund and Stirling polynomials
Authors: Ward Daniel
Published: February 2012

We provide a full asymptotic analysis of the N?rlund polynomials and Stirling
polynomials. We give a general asymptotic expansion-to any desired degree of
accuracy-when the parameter is not an integer. We use singularity analysis,
Hankel contours, and transfer theory. This investigation was motivated by a
need for such a complete asymptotic description, with parameter 1/2, during
this author's recent solution of Wilf's 3rd (previously) Unsolved Problem.
Grafted natural polymer as new drag reducing agent: An experimental approach
Authors: Abdulbari Hayder , Kamarulizam Nuraffini , Nour A.H.
Published: February 2012

The present investigation introduces a new natural drag reducing agent which
has the ability to improve the flow in pipelines carrying aqueous or
hydrocarbon liquids in turbulent flow. Okra (Abelmoschus esculentus) mucilage
drag reduction performance was tested in water and hydrocarbon (gas-oil)
media after grafting. The drag reduction test was conducted in a buildup
closed loop liquid circulation system consists of two pipes 0.0127 and 0.0381
m Inside Diameter (ID), four testing sections in each pipe (0.5 to 2.0 m),
tank, pump and pressure transmitters. Reynolds number (Re), additive
concentration and the transported media type (water and gas-oil), were the
major drag reduction variables investigated. The experimental results show
that, new additive drag reduction ability is high with maximum percentage of
drag reduction (%Dr) up to 60% was achieved. The experimental results showed
that the drag reduction ability increased by increasing the additive
concentration. The %Dr was found to increase by increasing the Re by using
the water-soluble additive while it was found to decrease by increasing the
Re when using the oil-soluble additive. The %Dr was higher in the 0.0381 m ID
pipe. Finally, the grafted and natural mucilage showed high resistance to
shear forces when circulated continuously for 200 seconds in the closed-loop
system.
Improved synthesis and in vitro study of antimicrobial activity of α,β-unsaturated and α-bromo carboxylic acids
Authors: Vitnik Vesna , Milenkovic Marina , Dilber Sanda , Vitnik Zeljko , Juranic Ivan
Published: February 2012

A series of ?,?-unsaturated and ?-bromo carboxylic acids were identified as
potent antimicrobial agents. Antimicrobial activity was evaluated using broth
microdilution method. All acids 1-12 exhibit a significant activity against
nine laboratory control strains of bacteria and two strains of yeast Candida
albicans. The tested acids were efficiently prepared by optimized
phase-transfer-catalyzed (PTC) reactions of ketones with bromoform and
aqueous lithium hydroxide in alcoholic solvent with TEBA as catalyst.
Drmno lignite field (Kostolac basin, Serbia): Origin and palaeoenvironmental implications from petrological and organic geochemical studies
Authors: Stojanovic Ksenija , Zivotic Dragana , Sajnovic Aleksandra , Cvetkovic Olga , Nytoft Peter , Scheeder Georg
Published: February 2012

The objective of the study was to determine the origin and to reconstruct the
geological evolution of lignites from the Drmno field (Kostolac Basin,
Serbia). For this purpose petrological and organic geochemical analyses were
used. Coal from the Drmno field is typical humic coal. Peat-forming
vegetation dominated by decay of resistant gymnosperm (coniferous) plants,
followed by prokaryotic organisms and angiosperms. Coal forming plants
belonged to the gymnosperm families Taxodiaceae, Podocarpaceae, Cupressaceae,
Araucariaceae, Phyllocladaceae and Pinaceae. Peatification was performed in
neutral to slightly acidic, fresh water environment. Considering that organic
matter of Drmno lignites was deposited at the same time, in the relatively
constant climate, it could be supposed that climate probably had only small
impact on peatification. Therefore, variations in compositions of macerals
and biomarkers indicate changes in the water level, due to seasonal drying of
the mire, which caused vegetation differences in the palaeoplant communities
and changes of redox conditions (from anoxic to slightly oxic) during
peatification. Diagenetic transformations of the organic matter were mainly
governed by microbial activity, rather than thermal alteration.
Three-dimensional registration of tomography data for quantification in biomaterials science
Authors: Müller Bert , Deyhle Hans , Lang Sabrina , Schulz Georg , Bormann Therese , Fierz Fabienne C. , Hieber Simone E.
Published: February 2012

The paper shows the benefit of registration tools in the quantitative analysis of tomography data. For this purpose three-dimensional datasets, i.e. target design in rapid prototyping, hard X-ray tomography, and magnetic resonance tomography, were registered with rigid, affine and non-rigid algorithms. Using rigid registration, we aligned individual tomograms to obtain one three-dimensional dataset per specimen, compared human teeth to determine abrasion, and optimized the acquisition parameters in clinical computed tomography. Affine registration was used to determine the sintering-induced shrinkage of hydroxyapatite scaffolds. Using non-rigid registration, we gained insight into tumor morphology imaged by different modes of micro computed tomography. In addition, the fixation-induced shrinkage of tumor tissue and the local deformation of brain tissues as well as the shape changes in nickel titanium alloys were quantitatively determined. Three-dimensional registration is, therefore, a powerful means to count back any influence on morphology of tissues and to quantitatively compare data of different tomography modalities.
Fatigue induced deformation of taper connections in dental titanium implants
Authors: Zabler Simon , Rack Tatjana , Rack Alexander , Nelson Katja
Published: February 2012

The present study deals with in-situ microgap measurements in the internal taper connections of dental implants. Using X-ray phase contrast microtomography, the connecting interface between implant and abutment is probed non-destructively in three dimensions. Interference fringes across the conical interface occur due to the presence of microgaps, their intensity being a measure of the gap's width. Thus, for each point on the interface, interferences are extracted from the volumetric image in terms of normal projection maps which are, at selected points, compared to forward simulations to quantify the local gap width. Four designs of dental implants are tested in the “as-received” state as well as after application of cyclic extra-axial load. Results show different degrees of microgap opening by cyclic deformation according to the implants' design as well as a great amount of detail on the actual interface, i. e. fretting scars, grooves and wear debris.
3D image analysis and stochastic modelling of open foams
Authors: Liebscher André , Redenbach Claudia
Published: February 2012

We present methods for the geometric characterisation and stochastic modelling of open foams based on tomographic 3D image data. In the first step, geometric characteristics of the foam microstructure are estimated from the image. Using these characteristics, a random tessellation model is fitted to the cell system of the foam. The edges of this tessellation then serve as a skeleton for the foam's strut system. The focus of the paper is on the correct simulation of the foam's locally varying strut thickness in the model. For this purpose, the local strut thickness and the strut profiles are estimated from the image and reproduced in the model using locally adaptable morphology.
Estimation of the probability of finite percolation in porous microstructures from tomographic images
Authors: Ohser Joachim , Ferrero Claudio , Wirjadi Oliver , Kuznetsova Alina , Düll Jochen , Rack Alexander
Published: February 2012

Percolation is an important property of porous media, as it describes the connectivity of pores. We propose a novel, direction-dependent percolation probability which can be efficiently estimated from three-dimensional images obtained by microtomography. Furthermore, in order to describe the penetrability of the pore space by particles of a given diameter or a fluid of a given surface tension, we introduce a percolation probability depending on the width of the pores, from which we may also derive a measure of the mean pore channel width. As application examples, we consider the penetrability of porous beryllium pebbles, the connectivity of pores in arctic firn, the percolation of the pore space of aluminum foams and the mean width of the percolating space between the fibers in a laminate's percolating pore space.
Morpho-topological volume analysis of porous materials for nuclear applications
Authors: Pieritz Romeu , Spino José , Vladimirov Pavel , Ferrero Claudio
Published: February 2012

The filtered medial line operator is a methodological tool for the morphological and topological analysis of reconstructed samples exhibiting either a porosity network or a granular structure such as bead packs. An application example of this methodology is the evaluation of the pore structure and the derived topological parameters of nanocrystalline 4Y-ZrO2 specimens simulating the high burn-up structure of UO2 fuel. The data indicate the absence of percolation paths at the experimental resolution, which is a beneficial property in terms of retaining fission gasses during the in-pile operation of the fuel. Furthermore, the analysis revealed a tendency for pore coalescence, which could explain the departure from the ideal behaviour of some physical properties typical of material matrices with a population of merely spherical pores. The same analytical tool is also used to characterise the porosity network created by gas bubbles in neutron irradiated beryllium samples, a material meant to be used for the blanket of the forthcoming generation of Tokamak fusion reactors. In particular, the preliminary results of the quantitative analysis performed on the porosity of the beryllium matrix as well as the initial investigation of its percolation properties are reported.
In-situ X-ray microtomography study of the movement of a granular material within a die
Authors: McDonald Samuel A. , Harris David , Withers Philip J.
Published: February 2012

Optimising the manufacture of powder-processed components requires an understanding of the 3-D movement and behaviour of granular materials during processing. X-ray microtomography has been employed to study the 3-D flow behaviour of a metallic powder in-situ within a die as a function of the displacement of a punch into the die. In particular, the powder transfer behaviour for various open and closed die/punch geometries has been compared, including situations where features exist within the die and on the punch, cases where the die is both open and closed at the top, and finally where the punch itself contains a groove in the centre providing a gap into which powder can flow. Digital image correlation (DIC) has enabled the determination of local vector displacements of powder around the features within the die cavity as a function of punch movement and powder constraint to reveal bulk granular movement and densification. Zones of relatively stagnant flow are observed above a fixed insert within the die cavity, at the opening of a gap within a punch, and as a result of a closed die configuration, the latter showing transitions between the stagnant zones and much more mobile regions and the resulting powder compaction/dilation. As well as providing a means of developing practical die fill and compaction strategies that homogenise densification and thus improve product quality, the technique can also provide unique 3-D flow trajectories for model development.
Evaluation Of Semen And Non-Return Rate Of Bulls In Artificial Insemination (AI) Center
Authors: Nasrin S , Amin MR , Alam MK
Published: February 2012

The experiment was conducted to evaluate the bull performance based on semen quality and 60 days non-return rate. Data were collected from 60 ejaculates and 525 services. Semen for insemination was used from bulls of different genetic groups (2 Holstein cross, 1 Sindhi cross, 1 Sahiwal cross and 1 Red Chittagong). Individual bull effect was found to be significant (P<0.01) on volume per ejaculate, mass motility, sperm concentration, live sperm and normal sperm percentage. The significantly (P<0.01) highest volume per ejaculate, sperm concentration, live sperm and normal percentage were found in Holstein cross and lowest in Red Chittagong Bull. Non-return rate was highest in Holstein cross bull and lowest in Red Chittagong Bull. Significant (P<0.01) positive correlation was observed in mass motility, live sperm and normal sperm percentage with non-return rate. It was concluded that Holstein cross Bull was the best among the bulls. DOI: http://dx.doi.org/10.3329/bjas.v37i2.9875 BJAS 2008; 37(2): 1-7
Genetic Evaluation Of Bangladesh Livestock Research Institute Cattle Breed-1 : Heritability And Genetic Correlation
Authors: Deb GK , Mufti MM , Mostari MP , Huque KS
Published: February 2012

Heritability and genetic correlation of economic traits of Bangladesh Livestock Research Institute (BLRI) Cattle Breed-1 (BCB-1) were estimated with Residual Maximum Likelihood (REML) principle. The BCB-1 is a native cattle breed developed by BLRI through selective breeding among indigenous cattle of Bangladesh. Data asserted from performance record sheets of 500 animals maintained during 1992 to 2005 were analyzed for estimation of genetic parameters. The heritabilities were estimated with single trait animal model for age at service and age at first calving and those of single trait repeatability model for other traits. However, two traits animal models were used for estimation of genetic correlations among different traits. The model includes sex, season and year of birth, parity, generation and additive genetic merit of each individual. The estimated heritabilities were higher for lactation milk yield (LMY, 0.404) and age at first calving (AFC, 0.404) followed by moderate estimates of daily milk yield (DMY, 0.257), lactation length (LL, 0.333), peak milk yield (PMY, 0.335), milk yield per day of calving interval (MYCI, 0.227), age at first service (AFS, 0.316), calving interval (CI, 0.273), and post partum heat period (PPHP, 0.276). The genetic correlations of lactation milk yield were high with DMY (+0.797), LL (+0.797) and MYCI (+0.876), moderate with CI (+0.399), PPHP (+0.205) and DP (-0.404) and low with AFS (-0.048) and AFC (-0.025). The moderate to high heritabilities for along with high genetic correlations among most of the milk yield traits emphasized continuation of selective breeding program for maximization of genetic improvement of this breed. The information generated in the present study may also be used in planning breeding program for other indigenous cattle germplasm of the country. DOI: http://dx.doi.org/10.3329/bjas.v37i2.9878 BJAS 2008; 37(2): 25-33
The Bioavailability Of Phosphorous From Bone Meal And Triple Super Phosphate And Its Effects On Indigenous Growing Cattle
Authors: Rahman MM , Khandaker ZH , Khaleduzzaman ABM
Published: February 2012

The bioavailability of phosphorous, and blood serum and rumen liquor P level was studied in indigenous growing cattle by feeding bone meal and Triple Super Phosphate (TSP) with control diet. Nine indigenous growing cattle (live weight of 164 ± 21 kg) were randomly assigned in a Completely Randomized Design (CRD) to three dietary treatments, consisted of a basal diet (T0) of 0.16% P and experimental diets supplemented with bone meal (T1) and triple super phosphate (T2) to provide P level of 0.44%. All diets were formulated to be iso-nitrogenous and iso-caloric. Three cannulated animals were used for rumen liquor P level study by feeding three diets. Apparent absorption and balance of P were significantly (P<0.01) higher in T1 and T2 diets than that of diet T0, but true absorption did not differ significantly (P>0.05). Bioavailability of P of control diet (37.41%), bone meal (81.45%) and triple super phosphate (80.49%) were significantly differed (P<0.01). Rumen liquor and blood serum P level differed significantly (P<0.01). Supplementation of bone meal and triple super phosphate results in high blood serum P (P>0.05) with no difference between bone meal and triple super phosphate. The results suggested that the bioavailability of P from bone meal and TSP was high and dietary supplementation of P with bone meal and TSP improved P retention and blood serum P level. DOI: http://dx.doi.org/10.3329/bjas.v37i2.9882 BJAS 2008; 37(2): 58-65
Meat Production Potential Of Different Cross-Bred Ducklings
Authors: Ansary E , Mahiuddin M , Howlider MAR , Hai MA
Published: February 2012

A study was conducted to determine the meat production potential of Pekin (P) x Pekin (P), P x Desi (D) and P x Jinding (J) ducklings up to 8 weeks of age. 54 day old ducklings were randomly allocated to 3 genotypic treatments having 3 replications in each genotype. One duckling from each replication was dissected to determine the meat yield. The initial and final live weight was found highest (P<0.01) in P X P, followed by those of P X D and P X J ducklings respectively. Feed conversion was poor in P X J, better in P X P and best in P X D (P<0.01). However, feed conversion for all genotypes decreased with the advance of age. At all ages except 1st week, better feed utilization was observed in P X D crossbred than that in P X P and P X J. Higher breast meat was observed in P X P (P<0.05) than in P X D and P X J. Thigh meat was found higher (P<0.05) in P X P and P X D than that in P X J. Considering the growth performance (growth rate and feed utilization) and meat yield characteristics, it may be concluded that crossing of Pekin with local ducks might produce a suitable genotype to improve meat production potential of duck to reared under Bangladesh condition. DOI: http://dx.doi.org/10.3329/bjas.v37i2.9885 BJAS 2008; 37(2): 82-88
Comparative Study On The Productivity And Profitability Of Commercial Broiler, Cockerel Of A Layer Strain And Cross-Bred (Rir × Fayoumi) Chicks
Authors: Sarkar PK , Chowdhury SD , Kabir MH , Sarker PK
Published: February 2012

An experiment was conducted to compare the productivity and profitability of commercial broiler, cockerel and cross-bred (F1 RIR ? × Fayoumi ?) chicks up to target body weights of 850, 1000 and 1250g. Two hundred sixteen birds of 3 genotypes each of 72 birds having 18 chicks in each replication were considered. Commercial broiler starter diet was fed to experimental birds ad libitum. Similar care and management were provided to birds of all treatment groups. Commercial broilers attained the target weights of 850, 1000 and 1250g at the age of 21, 24 and 28 days respectively whereas cockerels attained weights close to those targets at 56, 63 and 74 days respectively and in the case of cross-breds, the days were 63, 77 and 90 for those target weights respectively. Feed conversion ratio (FCR) was best in broilers, followed by cockerels and cross-bred chicks respectively. The highest mortality (8.3%) was found in cross-bred group when reared up to target weight of 1250g. The mortality of broiler was 1.4% and no bird was died in cockerel group. Broiler was most profitable (21.11 Tk/kg live bird) at the target weight of 1250g whereas profit from cockerel varied little (21.78, 21.07 and 21.63 Tk/kg live bird against the target weights of 850, 1000 and 1250g respectively) amoung target weights. Therefore, appropriate weight to market these birds was at 850g to minimize the risk of diseases and other management works. Marketing of cross-bred chicks was most profitable (8.43 Tk/kg live bird) at 850g target weight and loss was incurred when rearing was continued up to 1250g. On the basis of results of productivity, it was concluded that commercial broiler, cockerel and cross-bred chicks could be reared upto 28, 56 and 63 days respectively to reach target weights close to 1250, 850 and 850g respectively to obtain maximum profit.? DOI: http://dx.doi.org/10.3329/bjas.v37i2.9886 BJAS 2008; 37(2): 89-98
Potassium Diformate : A New Alternative To Antibiotic Growth Promoters
Authors: Chowdhury R , Haque MN , Islam KMS , Khan MJ
Published: February 2012

Potassium diformate (Formi) is odorless, low-corrosive and easy to handle. The European Union (EU) has approved it as non-antibiotic growth promoter, for use in non ruminant feeds. Maximum inclusion level of potassium diformate is 1.8% as registered by the European authorities which can improve weight gain up to 14%. Potassium diformate contains the active ingredients free formic acid as well as formate has the strong anti microbial effect in stomach and also in duodenum. Potassium diformate with its growth promoting and health enhancing effect has proven to be an alternative to antibiotic growth promoters. Its special effect on the micro flora is regarded as the main mode of action. 1.8% potassium diformate in growing pig diets also significantly increase Feed intake and feed conversion ratio was significantly improved where growing pig diets was supplemented with 1.8% potassium diformate. It was also reduced pH in the stomach and duodenum. potassium diformate 0.9% significantly reduced the pH of duodenal digesta. DOI: http://dx.doi.org/10.3329/bjas.v37i2.9887 BJAS 2008; 37(2): 99-105
Comprehensive and Facile Synthesis of Some Functionalized Bis-Heterocyclic Compounds Containing a Thieno[2,3-b]thiophene Motif
Authors: Mabkhot Yahia N. , Barakat Assem , Al-Majid Abdullah M. , Alshahrani Saeed A.
Published: February 2012

A comprehensive and facile method for the synthesis of new functionalized bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif is described. The hitherto unknown bis-pyrazolothieno[2,3-b]thiophene derivatives 2a–c, bis-pyridazin othieno[2,3-b]thiophene derivatives 4, bis-pyridinothieno[2,3-b]thiophene derivatives 6a,b, and to an analogous bis-pyridinothieno[2,3-b]thiophene nitrile derivatives 7 are obtained. Additionally, the novel bis-pyradazinonothieno[2,3-b]thiophene derivatives 9, and nicotinic acid derivatives 10, 11 are obtained via bis-dienamide 8. The structures of all newly synthesized compounds have been elucidated by 1H, 13C NMR, GCMS, and IR spectrometry. These compounds represent a new class of sulfur and Nitrogen containing heterocycles that should also be of interest as new materials.
Emodin Prevents Intrahepatic Fat Accumulation, Inflammation and Redox Status Imbalance During Diet-Induced Hepatosteatosis in Rats
Authors: Alisi Anna , Pastore Anna , Ceccarelli Sara , Panera Nadia , Gnani Daniela , Bruscalupi Giovannella , Massimi Mara , Tozzi Giulia , Piemonte Fiorella , Nobili Valerio
Published: February 2012

High-fat and/or high-carbohydrate diets may predispose to several metabolic disturbances including liver fatty infiltration (hepatosteatosis) or be associated with necro-inflammation and fibrosis (steatohepatitis). Several studies have emphasized the hepatoprotective effect of some natural agents. In this study, we investigated the potential therapeutic effects of the treatment with emodin, an anthraquinone derivative with anti-oxidant and anti-cancer abilities, in rats developing diet-induced hepatosteatosis and steatohepatitis. Sprague-Dawley rats were fed a standard diet (SD) for 15 weeks, or a high-fat/high-fructose diet (HFD/HF). After 5 weeks, emodin was added to the drinking water of some of the SD and HFD/HF rats. The experiment ended after an additional 10 weeks. Emodin-treated HFD/HF rats were protected from hepatosteatosis and metabolic derangements usually observed in HFD/HF animals. Furthermore, emodin exerted anti-inflammatory activity by inhibiting the HFD/HF-induced increase of tumor necrosis factor (TNF)-α. Emodin also affected the hepatocytes glutathione homeostasis and levels of the HFD/HF-induced increase of glutathionylated/phosphorylated phosphatase and tensin homolog (PTEN). In conclusion, we demonstrated that a natural agent such as emodin can prevent hepatosteatosis, preserving liver from pro-inflammatory and pro-oxidant damage caused by HFD/HF diet. These findings are promising, proposing emodin as a possible hindrance to progression of hepatosteatosis into steatohepatitis.