bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence, Cause, and Location of Palatal Fistula in Operated Complete Unilateral Cleft Lip and Palate: Retrospective Study
Authors: De Agostino Biella Passos Vivian , De Carvalho Carrara Cleide Felício , Da Silva Dalben Gisele , Costa Beatriz , Gomide Marcia Ribeiro
Published: April 2013

Objective

To evaluate the prevalence of fistulas after palate repair and analyze their location and association with possible causal factors.

Design

Retrospective analysis of patient records and evaluation of preoperative initial photographs.

Setting

Tertiary craniofacial center.

Participants

Five hundred eighty-nine individuals with complete unilateral cleft lip and palate that underwent palate repair at the age of 12 to 36 months by the von Langenbeck technique, in a single stage, by the plastic surgery team of the hospital, from January 2003 to July 2007.

Interventions

The cleft width was visually classified by a single examiner as narrow, regular, or wide. The following regions of the palate were considered for the location: anterior, medium, transition (between hard and soft palate), and soft palate.

Main outcome measures

Descriptive statistics and analysis of association between the occurrence of fistula and the different parameters were evaluated.

Results

Palatal fistulas were observed in 27% of the sample, with a greater proportion at the anterior region (37.11%). The chi-square statistical test revealed statistically significant association ( P ≤ .05) between the fistulas and initial cleft width ( P = .0003), intraoperative problems ( P = .0037), and postoperative problems ( P = .00002).

Conclusions

The prevalence of palatal fistula was similar to mean values reported in the literature. Analysis of causal factors showed a positive association between palatal fistulas with wide and regular initial cleft width and intraoperative and postoperative problems. The anterior region presented the greatest occurrence of fistulas.
Successful Field Implementation of a Novel Solids-Free System to Control Fluid Loss During Overbalanced Workover Operations in Southern Argentina
Authors: Vasquez Julio , Bonapace Juan , Gonzales Javier , Quintavalla Rodrigo
Published: April 2013

During workover and completion operations, even a small overbalanced hydrostatic pressure can result in a significant loss of fluid to the formation, especially in high-permeability formations. This situation becomes even more drastic in depleted reservoirs, horizontal wells, or in zones that have been previously fractured and packed. Controlling fluid loss into the formation is of critical importance during overbalanced workover operations to minimize near-wellbore (NWB) damage invasion by the completion fluid, which can yield problems associated with poor wellbore cleanout and loss of hydrocarbon reserves. In addition, fluid loss can increase costs associated with rig time and treatments devoted to restore the initial condition of the formation. In many hydrocarbon fields in southern Argentina, controlling fluid loss before NWB cleanout treatments is challenging because it can cause pressure differential sticking of the coiled tubing (CT) and/or inability to pump the treatment into the desired interval. This paper presents the successful field application of a novel solids-free fluid-loss (SFFL) system during wellbore cleanouts in the Cerro Dragon oilfield, which is located on the west side of San Jorge Gulf (SJG) basin in the Chubut Province of Argentina.

The SFFL system relies on water-soluble polymer that decreases matrix permeability to aqueous fluids, limiting leakoff into treated zones. This polymer immediately adsorbs to the surface of the rock, eliminating the need to shut the well in. In addition, this system does not require the use of breakers or a cleanup stage to reestablish hydrocarbon production once the workover operation has been performed. Laboratory test data show the capability of the material to control fluid leakoff and achieve high levels of regained permeability to hydrocarbons. Traditional techniques to minimize fluid loss use solids or viscous pills, although it has been amply documented that these systems can damage the formation if not properly removed after the treatment.

To date, about 200 treatments have been performed with this novel SFFL system. The paper discusses field results from the application of this system during overbalanced workover operations in Argentina, including the job design and post-treatment results. This system has been proposed for returning partial and total loss to full circulation in overbalanced operations, such as (1) lost-circulation events occurring during cementing, fracturing and drilling, (2) well intervention cleanouts by CT and hydraulic workover (HWO), (3) gravel packing, (4) replacement of artificial lift equipment (i.e., electrical submersible pumps), and (5) overbalanced tubing-conveyed perforating (UTCP).
A Practical Economic Optimization Approach with Reservoir Flow Simulation for Infill Drilling in a Mature Oil Field
Authors: Al-Mudhafer Wathiq J.
Published: April 2013

A practical optimization approach has been coupled with a commercial reservoir simulator to evaluate the optimal number and locations of infill wells in a conceptual sector of the Main Pay in South Rumaila Oil Field in Iraq. This field, of 58-years of production, has 40 producing wells. There is also an edge water drive from the infinite active aquifer at the east and west flanks. The water drive from the west flank is more than 20 times the drive from the east flank. Therefore, twenty injection wells have been drilled located at the east flank to maintain and balance the reservoir pressure.

After achieving the reliable history matching and running the simulator for a future period until 31 December 2020, the optimization approach has been implemented via spreadsheet considering the aspects of Net Present Value as objective function. The Net Present Value (NPV) is a function of economic variables representing costs and revenues. The revenue is directly proportional to the cumulative oil production that has been predicted by the reservoir model for the entire field. The costs include capital (CAPEX) and operational (OPEX) expenditures. There are ten assigned location of wells taken as a premise to be production wells. These 10 locations have been ranked according to the highest value of permeability and oil saturation spatial distribution in the reservoir in order to be evaluated considering achieving the highest NPV. The optimal number of infill wells was three, six, and ten when the NPV is calculated by the end of 2015, 2017, and 2022, respectively and all the wells at the three cases located at the crest of the reservoir. These optimal wells don't have the maximum cumulative oil production; however, they have the maximum Net Present Value especially at the first two prediction cases.
A Comparison between Capillary and Electrical Properties of Rock Samples Obtained at Ambient Conditions and Reservoir Conditions
Authors: Aboujafar Sami M. , Amara Mohamed A.
Published: April 2013

Determining the capillary pressure behavior of rocks at reservoir temperature and pressure is vital in understanding the displacement mechanism in the reservoir. An understanding of the displacement mechanism is essential to evaluate its effect on fluid saturations and oil recovery. The evaluation of saturations and thus oil reserves from resistivity logs requires laboratory determination of both the cementation factor (m) and the saturation exponent (n) under conditions as representative as possible of reservoir ones. Special laboratory equipment using air and actual formation brine at reservoir temperature and under effective overburden pressure was developed. The porous plate method was used to determine capillary pressure curves and saturation exponent at ambient conditions and at full reservoir conditions, (reservoir pressure and temperature) on sandstone core plugs from a Libyan reservoir.

The main objective of this study was to determine whether any difference exists between the capillary and electrical properties obtained at ambient conditions and those obtained at reservoir conditions for rock samples. Prior to the test, the effect of overburden pressure on porosity and formation factor can be studied.
SPDC Delivers 1st Onshore Smartwell Through Constructive Engagement with Stakeholders (Partners/Regulators/Internal SPDC)
Authors: Okpokpor O. A. , Nnanna E. , Otutu F. , Alabi I. B. , Azoom l , Uchendu C. C. , Oguntimehin A. B
Published: April 2013

Smartwell has become a routine technology solution in various parts of the world (including Nigeria) but is yet to receive total acceptance in Nigeria as the Industry regulators have remained opposed to commingled production pending demonstrable evidence of production allocation to individual producing reserves. It is still a frontier project in Nigeria and therefore requires a dedicated and concerted approach of winning stakeholders' acceptance. Various challenges, ranging from risk aversion to fears of a repeat first attempt ‘partial success' experience, contributed to the current low (near zero) performance of Shell Nigeria in the Nigerian Smart Completion deployment hierarchy. Notably, Chevron is the industry leader in Nigeria with over 22 wells while Shell Nigeria is about the last with only one attempt. The single ‘failed' attempt of the technology in 2002 gave rise, in 2004, to a deployment strategy change which met with an opposition both internally and externally. Undeterred by the challenge of persuading all stakeholders to embrace a repeat trial, work continued assiduously towards ensuring that the technology benefits are fully harnessed/realized through an aggressive and transparent approach of constructive stakeholders' engagements, development of pragmatic contracts and detailed researches into best practices. This paper presents a transparent and focused approach adopted through all stages of the project, which culminated in the final ‘textbook' Smartwell deployment. It also outlines how stakeholders involvement in the Major Smartwell contract initiation and award coupled with a collective orchestration of deployment planning further enabled a hitch-free deployment. Notably, this paper buttresses how the quest for success assurance and building of stakeholders' confidence, culminated into the constitution of a project deployment team comprising of operator, Partners, regulators and Contractors' representatives. The project team was tasked with the responsibility of working collaboratively to ensure success of the deployment as it would enable the next FDP for the field.
Reservoir Management Tool-Kits in Offshore Khafji Field: Successful Solutions for Field Case Studies on Water Conning Problems in Sandstone Reservoirs
Authors: Moawad Taha M. , Al-Dhafeeri Abdullah M. , Mohamed Tawakol I.
Published: April 2013

A sandstone reservoir (SA) is the main producer reservoir in offshore Khafji oil field. This field has been producing since 1959. However, for time being, some wells suffer from excessive water production especially in old vertical wells. In addition, early water breakthrough in vertical wells is mainly due to high permeability streaks and unfavorable mobility ratio.

Therefore, controlling water production is a challenge for reservoir management team work in Khafji Joint Operations (KJO) because there are several different explanations for the water sources in SA sandstone reservoir. These sources could be one or combination of edge water movement and flow behind casing. This phenomena can occur due to high permeability streaks, and conductive channels or/and faults.

To sustain the KJO Maximum Sustainable Capacity (MSC), reservoir management in KJO should apply optimum development scenarios for reducing the water production utilizing several and effective water shut-off techniques due to production facility bottlenecks. Converting the old and high water production vertical wells to horizontal and lateral wells which have shown a high rate of success in terms of conducting better technique and scenario to retrieve and bring these wells into production with low water cut. The approaches included also reducing the choke size, cement jobs to shut-in watered out intervals and adding new perforations or re-perforating oil productive intervals. Several successful field cases have been applied in SA reservoir which resulted to high oil production with low water cut. This paper discussed more details of lessons learned and applied techniques to control excessive water production from oil wells and comparison in selecting them for applying optimum applicable techniques.

The results of water management techniques and scenarios to retrieve the wells are analyzed and discussed in this study. Reasons for conversion, directions, diagnosis, selected intervals, simulation results analysis, lessons learned, challenges and conclusions were addressed in this paper.
Flow assurance for subsea gas production systems in the deep water of Mediterranean Sea with lower glycol injection rates.
Authors: A.Moati Wael Hamed
Published: April 2013

Flow assurance is an engineering process provides comprehensive analysis to assure hydrocarbon fluids are transported through pipelines (small lines or trunk lines) in an economical and safe manner from the producing wells to the treatment plant. Thus, flow assurance covers the whole range of possible flow problems that can trigger in pipelines such as hydrate formation, erosion, and severe slugging or back pressure to the old producing wells if they are connected to the same network. This paper introduces a case study done on a new gas field named "Denise-B?? located in the Mediterranean Sea, Egypt.This field is planned to be on production after finishing drilling and completion phases of three wells (Denise-4, Denise-5 and Denise-S4). The main scope is to optimize the whole network to select the best development rates of the new field without any back out from the old producing ones. At the same time, overcoming any flow problems like hydrate formation since offshore wells and offshore transmission lines may be operating under conditions where hydrate formation is favorable. The paper highlights that the change of inhibitor from di-ethylene to mono-ethylene glycol has a significant impact on the required injection rates. It is found that using mono-ethylene glycol compared to di-ethylene glycol can save up to 45% of the required volume rate to lower the hydrate temperature with 5 0C margin with flowing gas temperature. This is also is linked to properly design the injection pump capacity. Hence; it enhances the confidence and supports the decision to use mono glycol as hydrate inhibitor at low injection rates in offshore gathering networks while reducing the operating costs.

Introduction

Some of the most severe production-operation hazards are risks associated with the transportation of fluids. When condensate, water, and gas simultaneously flow in a well or pipeline, a number of potential problems can arise. These problems can be related to flow instability, erosion, and solids formation (like hydrates) and can lead to serious risk of leakages or blockages. The pipeline simulation tools can be used to simulate the steady state of the gathering network that collects the production of fluids from different gas or oil fields. Thus; it can provide a quick but efficient view of the system highlighting its criticalities that require more attention from operational point of view.
Using Simple Analytical Approach in Estimating Remaining Resources and Evaluating a Long Shut-In Reservoir Compartment with Too Many Uncertainties
Authors: Darhim Noureldien M. , Nassar Ibrahim S.
Published: April 2013

M8 Complex is one of the hugest and oldest offshore platforms in Gulf of Suez, Egypt. Many Intensive studies are conducted to refurbish it after its accidental fire occurred in March 2004 destroying most of its structure parts in a try to reinstate its production (±5000 BOPD). M8 receives oil feed from 5 satellites which are producing from Kareem reservoir (Middle Miocene) through a total of 11 wells penetrating M8 compartment polygon.

The main challenge is that 3 of the 11 wells are drilled from another outside platforms which are not related to M8 as a complex but their effect still inside M8 Polygon; these 3 wells continued production even after M8 fire. Also some WIW's accidently still injecting inside the polygon during its shut-In period till now. That led to a more complications in calculating remaining volumes of hydrocarbon left in the reservoir because all parameters inside M8 compartment polygon have been dramatically changed since 2004 till now.

This paper presents a study to decide whether to refurbish and reclaim M8 or not which depends mainly on the current remaining hydrocarbon volume. It shows also a simple analytical approach used for accurately calculating the remaining resources leading to take appropriate decision. Paper also covers many recovery scenarios, challenges and uncertainties specially in locating oil pockets and estimating initial rate after reinstating.

Through this paper you will learn how to use a simple analytical approach to solve such a complicated problem. Paper will explain the Study Methodology, Volumetric Calculations, STOOIP Validation, RF Estimation & QC, WIW's effect during the Shut-In period, de-risking all uncertain parameters and Finally finding optimum method to recover the remaining volume & How to choose the optimum location(s) of the proposed producer(s) to be drilled – all of this by only using a conventional approach.
An Approach To Determine Sandstone/clastic Reservoir Rock Distribution Pattern In Fluvio-deltaic- Marginal Marine Environment - An Easy, Simple And Cost Effective Process.
Authors: Deb Sasanka Sekhar , Borgohain J. K. , Basha S. K.
Published: April 2013

Depositional environment of a sedimentary sequence plays a vital role in the nature of sediments and distribution pattern of sediments. Environment of deposition is generally determined by sedimentological study, wire line log interpretation from well data of specific locations. The spatial extrapolation in to nearby areas can not be done alone by sedimentological study/ log interpretation. There are a number of techniques / tools available to identify the distribution pattern of sediments deposited in different environments of a stratigraphic sequence. Sequence stratigraphy is now a well established technique for determining sediment distribution pattern in a sedimentary sequence deposited in varied depositional environments. This special technique requires an in-depth knowledge of the subject and sufficient palaeo-geological information about the study area. Often, it becomes difficult to conceptualize the basic framework of the sequence stratigraphy method due to limited regional information and scanty data. As for example in fluvio-deltic-shallow marine conditions with active sea level fluctuation coupled with rapid fluvial sedimentation, sporadic palaeogeographic information hampers conceptualization of geological model. In such a situation another technique can help in solving some of the uncertainties in depositional setting. Basic concepts of Sequence stratigraphy coupled with sand (reservoir) shale (nonreservoir) ratio mapping provide excellent result in identifying depositional pattern of reservoirs units. This is a simple, easy and cost effective way to understand the broad depositional setting of sediments without involving high technology/gadgets.

A case study from an area within the petroliferous Upper Assam Basin of Assam-Arakan geological province of India is presented here.
Rejuvenation of West Qarun Field
Authors: El-Behairy A.. , Abdel-Nabi M.. , Rizk Mahmoud , Abdel-Moneim E..
Published: April 2013

The West Qarun development concession is located in the Abu Gharadig basin of the Western Desert, approximately 200 km SW of Cairo City. The block comprises a gross area of 46.2 km2 and contains the producing West Qarun oil field. Oil production commenced in October 1994 from four wells with initial production rate 1200 BOPD. The field showed constant production for the last ten years before SOG acquired the concession at a level of ±500 BOPD. The cumulative oil production amounted to 6 MMSTB of 40 deg API non-sulfurous, slightly low gas-oil-ratio paraffinic crude mainly from the Abu Roash ‘G’ and Upper Bahariya reservoirs through fifteen wells.

SOG after acquiring the concession, in 2009, conducted 3D seismic survey in order to reveal the uncertainties concerning field structure and its interpretation opened new chances by indicating higher OOIP and new promising locations for drilling. The results of new drilled wells WQ-7, WQ-9, and WQ-10 proved the new interpretation and gave more confidence in the resulted figures.

The Abu Roash "G" producing sands are characterized by formation tightness. So applying of hydraulic fracturing technique to enhance the existing wells productivity showed excellent results. Also tight formations need large shut-in time to obtain accurate pressure measurements. Therefore a pilot test was conducted to study the effect of shut-in time on the pressure measurements which will be illustrated thereafter.

Based on the studies, a complete development plan was prepared and the application of the first stage resulted in increasing the production five times (from 500 to 2500 BOPD) and tripling the proven remaining reserves as well (from 6.3 MMSTB to 19.5 MMSTB).

This paper will illustrate the approaches applied for the rejuvenation of West Qarun field and emphasizes the role of reservoir characterization and reservoir management in maximizing the field value.
Innovative Gas Lift in Heavy Oil Wells: Case Study in Block 6, Sudan
Authors: Xueqing Tang , Guocheng Li , Alawad Fahmi Abdalla , Keqiang Yu , Bo Cai , Musa Tagwa Ahmed
Published: April 2013

Although heavy oil producers in Block 6, Sudan have been difficult to exploit with gas lift because crude oil has 19 °API, the reservoir pressure was low, and surface dead oil viscosity ranged from 30,000 to 40,000 cp. New advances have recently been made to increase oil production. These innovative practices include: (1)Injected condensate gas into the reservoir prior to gas lift, and soaked for a time (e.g.one day) sufficient for condensate-gas to dilute the heavy oil's API gravity, reduce viscosity, and pressurized the zone near the wellbore.(2)Large tubing string was extended to near the bottom of perforations, gas lift valves were not utilized to ensure that a continuous volume of high-pressure condensate gas was injected into the annulus, could blend with heavy oil at the bottom hole and avoided multi-point injection caused by possible sanding.(3)Sand trap was installed to capture the produced sand.(4)Injection pressure and injection gas rate were optimized to produce more condensate from the gas condensate reservoir for dilution of heavy oil at the wellbore.

Field data show that these new techniques have gained excellent results, with oil gain of 6-fold compared to average oil rate by PCP.
A Sedimentlogical & Integrated Case Study Towards More Understanding Of The Depositional Regimes In Complex Structures
Authors: Essam M.. , El-Sayed A.. , Benyamin M.. , El-Batal A..
Published: April 2013

This study discusses the depositional setting of the Upper Cretaceous clastic dominated Abu Roash G reservoirs of Cenomanian age which deposited during in an overall transgressive setting continued into the Turonian and reached culmination in the deposition of the overlying Abu Roash F limestone as a clear regional marker.

Abu Roash G is divided into two main units, Upper & Lower Abu Roash G separated by the transgressive surface represented by the Intra Abu Roash G limestone which is easily to be tracked allover Abu Gharadig basin. Each of the Upper or the Lower Abu Roash G units has more than one sand reservoir unit.

This study tries to construct a paleogeographic model for each of the sand units of Abu Roash G in Alam El Shawish area. The interpretation was derived from wireline logs, Image, seismic attributes, depositional regimes & the experience absorbed from the nearby areas in Abu Gharadig basin using calibrated correlation / sequence stratigraphic framework through detailed core based facies.

The sea level oscillation had a profound influence on sedimentation of Abu Roash"G" Member in Alam El Shawish area. Abu Roash "G" Sandstone reservoir provide a good case history for coastal setting & believed to be exhibit both regressive and transgressive trends. This is related in lateral changes in distribution of sandstone from tidal channel, tidal flat, and barrier bar to tidal bar cross Alam El Shawish fields & vertical change through the time.

According to the integrated vision of the geological & seismic data that always add value to any prospect, field, or basin, seismic attributes computed from the 3D seismic data set proved useful in relating different reservoir characteristics interpreted from well data. These attributes were merged into the geological models & provided a description of the porosity distribution in Bahga field.
Biomass Production and Quality of Indian‐Origin Forage Guar in Southern Great Plains
Authors: Rao Srinivas C. , Northup Brian K.
Published: April 2013

Guar [Cyamopsis tetragonoloba (L.) Taub.] is a summer annual pulse grown in semiarid regions of the world as a multi‐purpose vegetable, grain, cover, or fodder crop. Existing guar cultivars used in the U.S. southern Great Plains (SGP) were developed for grain production, and there are currently no forage cultivars available for the region. This study compared biomass production and nutritive values of plant products of three cultivars of Indian origin, forage‐ type guar with a commonly used grain cultivar (Kinman) to determine whether the Indian‐origin cultivars would be better production options for the SGP. Aboveground biomass was sampled at early and late vegetative stages, and physiological maturity. Samples collected at maturity were separated into grain, pods, and vegetative biomass. Nitrogen and in vitro digestible dry matter (IVDDM) concentrations were determined on all biomass components. Data were analyzed using mixed models with guar cultivars and growth stage as main effects, and years as a longitudinal (repeated) element. The Indian‐origin cultivars produced significantly (P < 0.05) more forage (13–22%) and less grain (26–36%) than Kinman. Growing season and time of season main effects on biomass production, N, and IVDDM concentrations of forage, pods, and grain were significant. Drier growing seasons produced 50 and 34% less forage and grain, respectively, that contained 26 and 16% more N, with 14 and 6% greater IVDDM. Results indicated additional genetic selection is required to identify productive and reliable forage‐type guar cultivars that are better suited to the variable growing conditions of the SGP.
A new method to minimize the chattering phenomenon in sliding mode control based on intelligent control for induction motor drives
Authors: Bendaas Ismail , Naceri Farid
Published: April 2013

This paper presents new method toward the design of hybrid control with
sliding-mode (SMC) plus fuzzy logic control (FLC) for induction motors. As
the variations of both control system parameters and operating conditions
occur, the conventional control methods may not be satisfied further. Sliding
mode control is robust with respect to both induction motor parameter
variations and external disturbances. By embedding a fuzzy logic control into
the sliding mode control, the chattering (torque-ripple) problem with varying
parameters, which are the main disadvantage in sliding-mode control, can be
suppressed, Simulation results of the proposed control theme present good
dynamic and steady-state performances as compared to the classical SMC from
aspects for torque-ripple minimization, the quick dynamic torque response and
robustness to disturbance and variation of parameters.
A Prevalence Study on Outdoor Air Pollution and Respiratory Diseases in Children in Zasavje, Slovenia, as a Lever to Trigger Evidence-based Environmental Health Activities
Authors: Kukec Andreja , Farkas Jerneja , Erzen Ivan , Zaletel-Kragelj Lijana
Published: April 2013

The aim of this study was to estimate the population burden of respiratory diseases in the Zasavje region of Slovenia that can be attributed to outdoor air pollution in order to gain relevant grounds for evidencebased public health activities. In 2008, 981 schoolchildren (age 6 to 12 years) were observed in a prevalence study. The prevalence of chronic respiratory diseases (CRD) and frequent acute respiratory symptoms (FARS) was related to the level of outdoor air pollution in the local environment (low, moderate and high pollution areas). Logistic regression was used as a method for statistical analysis. The prevalence of CRD was 3.0 % in low pollution areas, 7.5 % in moderate pollution areas, and 9.7 % in high pollution areas (p=0.005). After adjustment for the effects of confounders, 2.91-times higher odds for CRD were registered in high pollution areas in comparison to low pollution areas (p=0.017). The prevalence of FARS was: 7.8 % in low pollution areas, 13.3 % in moderate pollution areas and 15.9 % in high pollution areas (p=0.010). After adjustment for the effects of confounders, 2.02-times higher odds for FARS were registered in high pollution areas in comparison to low pollution areas (p=0.023). The study confirmed a significantly higher prevalence of CRD and FARS in children living in high pollution areas of Zasavje. These results at least partially prompted mutual understanding and cross-sectoral cooperation - prerequisites for solving complex problems involving the impact of air pollution on health.
Predicting the Biological Effects of Mobile Phone Radiation Absorbed Energy Linked to the MRI-obtained Structure
Authors: Krstić Dejan , Zigar Darko , Petković Dejan , Sokolović Dušan , Đinđić Boris , Cvetković Nenad , Jovanović Jovica , Đinđić Nataša
Published: April 2013

The nature of an electromagnetic field is not the same outside and inside a biological subject. Numerical bioelectromagnetic simulation methods for penetrating electromagnetic fields facilitate the calculation of field components in biological entities. Calculating energy absorbed from known sources, such as mobile phones when placed near the head, is a prerequisite for studying the biological influence of an electromagnetic field. Such research requires approximate anatomical models which are used to calculate the field components and absorbed energy. In order to explore the biological effects in organs and tissues, it is necessary to establish a relationship between an analogous anatomical model and the real structure. We propose a new approach in exploring biological effects through combining two different techniques: 1) numerical electromagnetic simulation, which is used to calculate the field components in a similar anatomical model and 2) Magnetic Resonance Imaging (MRI), which is used to accurately locate sites with increased absorption. By overlapping images obtained by both methods, we can precisely locate the spots with maximum absorption effects. This way, we can detect the site where the most pronounced biological effects are to be expected. This novel approach successfully overcomes the standard limitations of working with analogous anatomical models.
Structure and Properties Investigation of MCMgAl12Zn1 Magnesium Alloy
Authors: Dobrzański L.A. , Król M.
Published: April 2013

This work presents an influence of cooling rate on crystallization process, structure and mechanical properties of MCMgAl12Zn1 cast magnesium alloy. The experiments were performed using the novel Universal Metallurgical Simulator and Analyzer Platform. The apparatus enabled recording the temperature during refrigerate magnesium alloy with three different cooling rates, i.e. 0.6, 1.2 and 2.4°C/s and calculate a first derivative. Based on first derivative results, nucleation temperature, beginning of nucleation of eutectic and solidus temperature were described. It was fund that the formation temperatures of various thermal parameters, mechanical properties (hardness and ultimate compressive strength) and grain size are shifting with an increasing cooling rate.
The Effect of Toughening Combined with Microjet Cooling During Quenching (Solution Heat Treatment) of Calcium Carbide-Modified CuAl10Fe4Ni4 Alloy on its Mechanical Properties
Authors: Górny Z. , Nawarecka S. Kluska , Saja K.
Published: April 2013

The work presents the results of the experimental research concerning the impact of a heat treatment (toughening) of aluminum bronze CuAl10Fe4Ni4 on its mechanical properties. The conditions of the experiments and selected results are described. A detailed description of the effects of individual heat treatment conditions namely low and high temperature aging is also presented in the work.
Effect of Chemical Composition on Number of Eutectic Colonies in Ni-Mn-Cu Cast Iron
Authors: Janus A.
Published: April 2013

Determined were direction and intensity of influence of alloying additions on the number of eutectic graphite colonies in austenitic cast iron Ni-Mn-Cu. Chemical composition of the cast iron was 1.7 to 3.3% C, 1.4 to 3.1% Si, 2.8 to 9.9% Ni, 0.4 to 7.7% Mn, 0 to 4.6% Cu, 0.14 to 0.16% P and 0.03 to 0.04% S. Analysed were structures of mottled (20 castings) and grey (20 castings) cast iron. Obtained were regression equations determining influence intensity of individual components on the number of graphite colonies per 1 cm2 (LK). It was found that, in spite of high total content of alloying elements in the examined cast iron, the element that mainly decides the LK value is carbon, like in a plain cast iron.
Virtual Factory as a Method of Foundry Design and Production Management
Authors: Stawowy A. , Wrona R. , Brzeziński M. , Ziółkowski E.
Published: April 2013

The paper outlines the methodology of virtual design of a foundry plant as a system. The most important stage in the procedure involves the development of a model defined as a set of data about the system. Model development involves two stages: defining the model’s architecture and specifying the model data in the form of parameters and input-output relationships. The structure is understood as configuration of machines and transport units, representing the sub-systems and system components. As the main purpose of the simulation procedure is to find the characteristics of the system’s behaviour, the merits of the iterative method involving analysis, synthesis and evaluation of results are fully explored.
The Silumin Coat Structure on Alloy Ductile Iron
Authors: Szymczak T.
Published: April 2013

The work presents the research results of the silumin coat structure applied on the carbidic alloy ductile iron with the metal matrix: pearlitic, bainitic and martensitic. The coats were made in the AlSi5 silumin bath at the temperature tk = 750±5°C. The holding time of cast iron element in the bath was τ = 180s. Irrespective of the kind of tested ductile iron the obtained coat consisted of three layers with a different phase composition. The first layer from the cast iron ground “g1`” is built from Fe4CSi carbide which contains selected alloy additives of the cast iron. On it the second layer “g1``” crystallizes. It consists of the AlFeSi inter-metallic phase which can appear in its pure form or contain a small quantity of the alloy additives of the cast iron. The last external part of the layer “g2” mainly consists of the hypo-eutectic phases of silumin. The AlFeSi inter-metallic phases in the form of free precipitations with a lamellar or faceted morphology can also appear there. These phases also can contain a small quantity of the alloy additives of the cast iron. More than that, in all the layers of the coat there are graphite precipitations. The phenomenon of graphite movement to the coat is caused by intensive dissolving of the cast iron element surface by the aluminum of the silumin bath.
Interaction of Salinity and Phytohormones on Wheat Photosynthetic Traits and Membrane Stability
Authors: Pazuki Arman , Sedghi Mohammad , Aflaki Fatemeh
Published: April 2013

To evaluate phytohormones effects on stomatal conductance, chlorophyll fluorescence, membrane stability, relative water content and chlorophyll content under salinity, a factorial experiment with 4 replicates was conducted. Treatments were salinity (0, 3.5 and 7 dS/m), phytohormones (control, gibberellic acid and abscisic acid) and wheat cultivars (Gascogen, Zagros, and Kuhdasht). Results showed that a high level of salinity increased chlorophyll fluorescence and relative water content, while membrane stability, chlorophyll content, and stomatal conductance were decreased. Abscisic acid treatment had more effective role in membrane stability. Although membrane stability was much more under gibberellic acid treatment, restoration of membrane stability was considerable under abscisic acid treatment for Gascogen and Kuhdasht cultivars. Spraying of gibberellic acid induced the highest chlorophyll content in the three salinity levels and all of the cultivars. The maximum amount of stomatal conductance was achieved under gibberellic acid treatment. Abscisic acid caused less chlorophyll fluorescence in comparison to gibberellic acid. About relative water content, abscisic acid was effective in high salinity levels so that it caused stomatal closure, which reduced water loss and maintained turgor in plants.
Technology Enhanced Learning for Humanities by Active Learning − the Sinus Project Approach
Authors: Agre Gennady , Dochev Danail , Slavkova Liliana
Published: April 2013

The paper presents an approach to active learning facilitated by the use of semantic technologies. Some features of active learning and understanding of learning in humanities are discussed. The specifics of a well defined learning task - learner’s authoring of analytical materials, grounded by materials from a digital library - are analyzed to shape the functionality of experimental Technology Enhanced Learning (TEL) environment with a built-in domain and pedagogical knowledge. The environment structure and realization are discussed and a learning example is presented.
Pattern Synthesis Using Multiple Kernel Learning for Efficient SVM Classification
Authors: Seetha Hari , Saravanan R. , Murty M. Narasimha
Published: April 2013

Support Vector Machines (SVMs) have gained prominence because of their high generalization ability for a wide range of applications. However, the size of the training data that it requires to achieve a commendable performance becomes extremely large with increasing dimensionality using RBF and polynomial kernels. Synthesizing new training patterns curbs this effect. In this paper, we propose a novel multiple kernel learning approach to generate a synthetic training set which is larger than the original training set. This method is evaluated on seven of the benchmark datasets and experimental studies showed that SVM classifier trained with synthetic patterns has demonstrated superior performance over the traditional SVM classifier.
Multi-Criteria Models for Clusters Design
Authors: Radeva Irina
Published: April 2013

The paper describes economic agents’ integration in clusters on a predefined technological network. The process is divided and directed by three multi-criteria models. The first one allows selection of economic agents. The second one aims at definition of alternative cluster designs. The third model evaluates the risk of the clusters. The process and models are tested on nineteen economic agents.
Resolvent Estimates in l_p for Discrete Laplacians on Irregular Meshes and Maximum-norm Stability of Parabolic Finite Difference Schemes
Authors: Crouzeix Michel , Thomée Vidar
Published: April 2013

In an attempt to show maximum-norm stability and smoothing estimates for finite element discretizations of parabolic problems on nonquasi-uniform triangulations
we consider the lumped mass method with piecewise linear finite elements in one and two space dimensions. By an energy argument we derive resolvent estimate for the
associated discrete Laplacian, which is then a finite difference operator on an irregular mesh, which show that this generates an analytic semigroup in l_p for p‹∞
uniformly in the mesh, assuming in the two-dimensional case that the triangulations are of Delaunay type, and with a logarithmic bound for p=∞.
By a different argument based on a weighted norm estimate for a discrete Green's function this is improved to hold without a logarithmic factor for p=∞
in one dimension under a weak mesh-ratio condition. Our estimates are applied to show stability also for time stepping methods.
On the Strong Stability of Operator-Difference Schemes in Time-Integral Norms
Authors: Jovanović Boško S. , Matus Piotr P.
Published: April 2013

In this paper we investigate the stability of two-level operator-difference
schemes in Hilbert spaces under perturbations of operators, the initial condition and
right hand side of the equation. A priori estimates of the error are obtained in time-
integral norms under some natural assumptions on the perturbations of the operators.
Multigrid for the Wilson Mortar Element Method
Authors: Shi Zhong-Ci , Xu Xuejun
Published: April 2013

In this paper, a mortar finite element method is proposed for the
Wilson nonconforming element. Multigrid method is used to solve the resulting discrete
system.
Parameter–uniform Fitted Mesh Method for Quasilinear Differential Equations with Boundary Layers
Authors: Farrell Paul A. , O’Riordan Eugene , Miller John J.H. , Shishkin Grigorii I.
Published: April 2013

Singularly perturbed quasilinear boundary value problems exhibiting
boundary layers are considered. Special piecewise-uniform meshes are constructed
which are fitted to these boundary layers. Numerical methods composed of upwind
difference operators and these fitted meshes are shown to be parameter robust, in
the sense that the solutions satisfy an error estimate in the maximum norm which is
independent of the value of the singular perturbation parameter. Numerical results
supporting the theory are presented.
Difference Methods for Fuzzy Partial Differential Equations
Authors: Allahviranloo Tofigh
Published: April 2013

In this paper numerical methods for solving ’fuzzy partial differential
equations’(FPDE) is considered. Fuzzy reachable set can be approximated by proposed
methods with complete error analysis which is discussed in details. The methods are
illustrated by solving some linear and nonlinear FPDE.
Orthogonal Approximate Solution of Cauchy-type Singular Integral Equations
Authors: Smarzewski R. , Sheshko M. A.
Published: April 2013

Chebyshev polynomials of the first and second kind are used to derive
approximate solutions of the Cauchy-type singular integral equations.
Numerical Solution of a Rimming Flow Problem Using a Moving Mesh Method
Authors: Hegarty Alan F. , O'Brien Stephen B. G. , Sikwila Stephen
Published: April 2013

We consider the evolution of a thin film of viscous fluid on the inside surface of a cylinder with the horizontal axis, rotating with a constant angular velocity
about this axis. We use a lubrication approximation extended to the first order in the dimensionless film thickness (including the small effects of the variation of the film
pressure across its thickness and the surface tension) and numerically we compute the time evolution of the film to a steady state.
On Numerical Methods for a Boundary Layer on a Body of Revolution
Authors: Hossain Bayezid , Ansari Ali R. , Shishkin Gregorii I.
Published: April 2013

The flow of a viscous incompressible uid past a body of revolution with aparabolic profile when the stream is parallel to its axis falls into a class of problems that exhibit boundary layers. This problem does not have solutions in closed form, and is
modeled by boundary-layer equations. Using a self-similar approach based on a Blasius series expansion (up to two terms), the boundary-layer equations can be reduced to
a Blasius-type problem consisting of a system of three 3rd order ordinary differential equations on a semi-infinite interval. Numerical methods need to be employed to
attain the solutions of these equations and their derivatives, which are required for the computation of the velocity components, on a finite domain with accuracy independent
of the viscosity v, which can take arbitrary values from the interval (0; 1]. Numerical methods for which the accuracy of the velocity components depend on the number
of mesh points N, used to solve the Blasius-type problem, and do not depend on the viscosity v, are referred to as robust methods. To construct a robust numerical method
we reduce the original problem on a semi-infinite axis to a problem on the finite interval [0;K], where K = K(N) = lnN. Employing numerical experiments, we justify that
the constructed numerical method is parameter robust.
Solution of Some Differential Equations of Quantum Physics by the Numerical Functional Integration Method
Authors: Lobanov Y. Y. , Zhidkov E. P.
Published: April 2013

The application of the numerical functional integration method to the solution of differential equations in quantum physics is discussed. We have developed a
method of numerical evaluation of functional integrals in abstract complete separable metric spaces, which proves to have important advantages over the conventional Monte
Carlo method of path integration. One of the considered applications is the investigation of open quantum systems (OQS), i.e., systems interacting with their environment.
The density operator of OQS satisfies the known Lindblad differential equation. We have obtained the expression for matrix elements of this operator in the form of the
double conditional Wiener integral and considered its application to some problems of nuclear physics. Another application is the solution of the Scr¨odinger equation with
imaginary time and anticommuting variables for studying many-fermion systems. We have developed a numerical method based on functional integration over ordered subspaces.
The binding energies of some nuclei are computed using this method. Comparison of the results with those obtained by other authors and with experimental values
is presented.
A Priori Error Analysis for the hp-Version of the Discontinuous Galerkin Finite Element Method for the Biharmonic Equation
Authors: Mozolevski Igor , Süli Endre
Published: April 2013

We consider the hp-version of the discontinuous Galerkin finite element approximation of boundary value problems for the biharmonic equation. Our main concern is the a priori error analysis of the method, based on a nonsymmetric bilinear form with interior discontinuity penalization terms. We establish an a priori error bound for the method which is of optimal order with respect to the mesh size h , and nearly optimal with respect to the degree p of the polynomial approximation. For analytic solutions, the method exhibits an exponential rate of convergence under p- refinement. These results are shown in the DG-norm for a general shape regular family of partitions consisting of d-dimensional parallelepipeds. The theoretical results are confirmed by numerical experiments. The method has also been tested on several practical problems of thin-plate-bending theory and has been shown to be competitive in accuracy with existing algorithms.
Numerical Stability Analysis of Solutions of PDEs
Authors: Čiegis Raimondas , Čiegis Remigijus
Published: April 2013

In this paper we investigate two iterative methods for solving one problem of nonlinear optics. The main goal is not only to find a stationary solution but also
to investigate its stability. It is shown that both methods have very different stability
properties and the less stable algorithm is close to the approximation of the physically
important non-stationary problem. We also propose a new iterative algorithm for solving a more complicated problem which describes the optical conjugation in stimulated
Brillouin backscattering with pump depletion. This algorithm is based on a symmetrical splitting scheme and the nonlinear interaction is approximated by using the special
mass conservation property of the discrete problem. Thus, we obtain a conservative
iterative algorithm. The results of the numerical experiments are presented and they
confirm our theoretical conclusions.