bluuebunny/crossref_metadata_2025 huggingface dataset:
Best Practices and Lessons Learned After 10 Years of Digital Oilfield (DOF) Implementations
Authors: Saputelli Luigi , Cesar Bravo , Michael Nikolaou , Carlos Lopez , Cramer Ron , Toshi Mochizuki , Moricca Giuseppe
Published: October 2013

In the last decade, upstream oil industry faced an exponential increase of the use of real-time data, which lead to numerous digital oilfield (DOF) implementations. These have demonstrated the value to drive operations efficiency, optimize production, and maximize hydrocarbon recovery with better, faster decisions while reducing health, environmental and safety risks.

Since the appearance of computers and the internet, many enabling technologies entered the oil-patch. Over the years, various areas improved as a result of significant commercial, corporate and academic efforts. However, some specific concerns remain be the same as a decade ago: data, value proposition, work processes, people skills and other aspects of change management.

This paper focuses on the best practices that have made DOF implementations successful and the hard lessons learned. Many DOF implementations failed to deliver the expected value because of poor practices and misconceptions. These are presented in four interrelated areas: people, automated workflows, processes and technologies.

Management of change at various levels of the organization continues to be a critical success factor, e.g. the introduction of new systems, designing effective collaborative ways of working, training people, management support and having the right resources (time and financial) to focus on real-time oil and gas production optimization.

Automated workflows have been developed and deployed at various intensity levels. Although there is a lack of common language for defining workflows, there has been tremendous improvement in this area.

On the other hand, work processes had been an area of little improvement. Because of poor process definition and understanding, companies failed to adopt and sustain highly sophisticated workflows. In the paper, we discuss the effort required to properly describe work process that support DOF implementations. We also describe the technology challenges faced and how these can be mitigated in the future.
Stable Fracturing Fluids from Produced Waste Water
Authors: Kakadjian Sarkis , Thompson Joseph , Torres Robert , Trabelsi Siwar , Zamora Frank , Ait Hamlat Yahia
Published: October 2013

Environmental concerns and public opinion have elevated the visibility of hydraulic fracturing. Currently oil companies and operators acquire fresh water for fracturing treatments on the front end and pay to dispose or transport the flowback or produced water on the back end, increasing dramatically the cost of the hydraulic fracturing job. We report a newly developed fracturing fluid system utilizing 100% untreated produced water which eliminates the upfront costs of purchasing fresh water. In addition, the back end costs are significantly reduced by transporting produced and/or flowback water to locations for re-use rather than to disposal well(s) located miles away or even in other states.

This new system uses conventional gelling agents and crosslinkers used in active US shale plays, addressing the fracturing focus initiative.

This new fluid system was developed for temperature ranges between 120-300+ °F. Field tests prove shear stability and good proppant transport at 20 BPM through a 1.25 in sliding sleeve baffle. The fracturing fluid system can be designed for instant or delayed crosslinking in recycle water with total dissolved solids exceeding 300,000 mg/L with hardness exceeding 30,000 mg/L. Another concern in the past was the presence of boron in produced water. This system can be used in water containing boron levels exceeding 500 mg/L.

The code for recycle water has been broken utilizing this unique fracturing fluid system designed to conserve fresh water aquifers and recycle produced and flowback waters, reducing significantly disposal costs.

This paper reports laboratory testing of the fluid characteristics in untreated produced water from the Bakken as well as the outcome of hybrid fluids in field applications, recommendations for field applications and economic impacts on fracturing fluid systems.
Challenges in implementing digital oil field for production optimization in Joint Operations Kuwait
Authors: Bhat M. S. , Spain J.. , Silva N..
Published: October 2013

It is difficult to change the operating culture and its equilibrium in an oil field, especially when the price of oil and profits are high. This paper discusses the challenges faced while implementing a digital oilfield concept for production optimization at Joint Operations (JO) in Kuwait. The operations are in the onshore Partitioned Zone, an area between Kuwait and Saudi Arabia. This operation is unique in that it is operated jointly under separate concessions from two countries, Kuwait and Saudi Arabia, and involves a private player working alongside a national oil company during day-to-day operations. The production is from fields bordering Kuwait and Saudi Arabia and is staffed and funded equally by Saudi Arabian Chevron Inc. (SAC) and the Kuwait Gulf Oil Co. (KGOC). Some of the Chevron employees that rotate every 3 to 5 years from this location are familiar with the concept of the digital oil field (DOF). JO has set up a control center in the field. Approximately 50% of the wells are ‘on SCADA,’ meaning that the data from these wells are monitored in real time. JO wanted to implement real-time optimization, which would provide the engineers a tool at their desktop to monitor and optimize their wells in real time. The foremost challenge was to get all employees to adapt to a DOF concept. Several strategies have been considered to gain greater acceptance and usage of the DOF, some of which have yielded short-term gains. There is an attempt to generate greater user interest by providing daily reports from the software to show wells that are down along with their alarms. These wells are not part of the differed oil production. This paper discusses such strategies in addition to creating a sense of urgency, a top-down management approach and individual one-on-one training sessions, among others.
Use of a Variable Shape Distribution (VSD) Model to Populate Reservoir Properties in Tight Fractured Reservoirs for Numerical 3D Modeling
Authors: Aguilera R.. , Vargas J. Ramirez
Published: October 2013

The importance of unconventional resources is increasing every day. In Canada, unconventional gas accounts for an estimated 34% of the total gas production. In the United States the estimate is 54%. And we anticipate that the contribution of unconventional resources throughout the world will become significant in decades to come.

Most unconventional reservoirs are naturally fractured and also need to be hydraulically fractured to attain commercial production. Different authors have concluded that both, natural and hydraulically induced fractures make these reservoirs stress-sensitive causing various problems for modeling, such as poor history match and inaccurate forecasting. The solution to this problem is coupling the reservoir model with a geomechanical model, to take into account the changes in porosity and permeability due to changes in stresses during the life of the reservoir.

But inputting natural fracture data accurately in the simulator at different scales is challenging. Thus the objective of this study is the use of a variable shape distribution (VSD) model, which has never been utilized in the past in reservoir simulation, to build a more rigorous static model with a view to improve history matching, production forecasting, and modeling of tight fractured reservoirs. While other statistical models are not capable of fitting the whole scale spectrum of fracture properties without truncating the data, the VSD fits the complete set of non-truncated fracture data with a coefficient of determination (R2) of at least 0.97. This improves reservoir characterization and geostatistical modeling. Although application of the method concentrates only on a tight gas formation of the Western Canada Sedimentary Basin (WCSB) the workflow is presented in detail so that it can be reproduced in other tight naturally fractured reservoirs around the world.

It is concluded that the proposed methodology represents an improvement over previous approaches as the complete distribution of matrix and fracture properties, from very small to very large scales, is taken into account without any truncations. Results lead to proposals for drilling horizontal wells in areas of more intense natural fracturing.
Complexity Reduction of Multi-Phase Flows in Heterogeneous Porous Media
Authors: Ghommem Mehdi , Calo Victor M. , Efendiev Yalchin , Gildin Eduardo
Published: October 2013

In this paper, we apply mode decomposition and interpolatory projection methods to speed up simulations of two-phase flows in highly heterogeneous porous media. We propose intrusive and non-intrusive model reduction approaches that enable a significant reduction in the dimension of the flow problem size while capturing the behavior of the fully-resolved solutions. In one approach, we employ the dynamic mode decomposition (DMD) and the discrete empirical interpolation method (DEIM). This approach does not require any modification of the reservoir simulation code but rather postprocesses a set of global snapshots to identify the dynamically-relevant structures associated with the flow behavior. In a second approach, we project the governing equations of the velocity and the pressure fields on the subspace spanned by their proper orthogonal decomposition (POD) modes. Furthermore, we use DEIM to approximate the mobility related term in the global system assembly and then reduce the online computational cost and make it independent of the fine grid. To show the effectiveness and usefulness of the aforementioned approaches, we consider the SPE 10 benchmark permeability field and present a variety of numerical examples of two-phase flow and transport. The proposed model reduction methods can be efficiently used when performing uncertainty quantification or optimization studies and history matching.
Reliable Fracture Characterisation and Value Addition through Special Core Reorientation: Kuwait Case Study
Authors: Alenezi A. M. , Narhari S. R. , Alajmi N. H. , Pattnaik C.. , Rao J. D. , Al-ateeqi K. A. , Saffelbach C.. , Anis Abdel-Hamid , Chakravorty S..
Published: October 2013

Reliable fracture characterization is essential for efficient field development of tight carbonate reservoirs. A comprehensive campaign of core based fracture analysis was carried out on more than 7,000ft of deep tight carbonate (over 14500ft TVD and 3pu avg. porosity and 0.1 mD avg. perm) cores of Kuwait, spread over a number of wells covering a large area of over 1000sq km.

The aim of the study was to provide inputs for a detailed structural analysis of the area, with the help of reorientation of cores focusing on the geometrical and structural characteristics of each well. The reorientation procedure used a special core Goniometry process, which permits a totally hands-free 3D digitization of all planar and linear features. Reorientation of the cores is established using either the deviation data from the wells or through comparison with image log data.

In addition to the detailed integrated description of type, size, aperture and filling of fractures, a porosity/permeability model was generated after calculation of fracture frequency. By calculating the orientation and value of the permeability vectors, an indication of optimum direction of drilling was established for each well/area.

The natural fracture network obtained with open, partially-open and cemented fractures, together with induced stress-release fractures analysis, contributed to a better understanding of tectonic history and present-day stress in the studied area. A field synthesis map highlighted the main direction of all types of fractures and an actual stress map was worked out by compiling all directions of the maximum horizontal stress observed in the wells and oriented by the petal and centreline induced fractures.

The integration of the results with analyses of image log data, well log correlation data and seismic data provided critical information about the reservoir properties.
Realistic Fracture Conductivity Calculation Using Well Performance Data in Saudi Arabian Deep Gas Reservoirs
Authors: Rahim Zillur , Al-Anazi Hamoud , Al-Kanaan Adnan , Makmun Areiyando , Kayumov Rifat
Published: October 2013

The actual fracture conductivity contributing to gas flow after a proppant treatment is usually much lower than what is reported in the laboratory tests. This is because the ideal conductivity values can be impaired by numerous factors in the reservoir conditions – from high unconfined compressive strength to condensate yield – that cannot be fully captured in the laboratory measurements. Although there are many publications in the literature discussing this issue and software in the industry that predict certain percentage decreases in conductivity due to various reasons, these results are usually specific to certain reservoirs, formations, and laboratory tests and cannot be extrapolated or used for all reservoirs. To understand and compute actual conductivity values in Saudi Arabian gas reservoirs stimulated by proppant fracturing, a new workflow is proposed. The workflow involves using all available data to first calculate the actual fracture geometry using a mass balance and pressure matching. Subsequently, fracture conductivity is computed from another standard method, such as the Cinco-Ley correlation; and using industry software to estimate realistic conductivity values at static and dynamic conditions using closure pressure, actual well performance, and bottomhole flow pressure measurements. A range of fracture conductivity is computed during initial and later periods by matching the well performance data. The calculations show the fracture conductivity achieved after a fracture treatment at reservoir conditions and also how the values change during the production period of a well. Later, correlations relating to productivity increases with reservoir rock and pumping properties can be used to optimize fracture treatments such that a high rate can be maintained after a fracture treatment.
A Horizontal Drilling Breakthrough to Develop the New Resources: A Case Study in Developing the Unexploited Complex Reservoirs from Tarim Basin, West China
Authors: Shi Xiang Hong , Bai Xiang Deng , Qiu Bin , Zhu Yi , Xia Feng Guo , Tan Ping Jun , Li Fei , Chen Lin Jiang , Halomoan Parlindungan Monris , Xu Chong Hui , Wang Yong , Wang Da Hai , Bin Nie Xiang , Fei Wang , Xin Lin
Published: October 2013

Hadexun oil field, located onshore west China, has been in production for over 13 years. Most of the primary oil was produced from relatively thick oil reservoirs. The development plan has now shifted toward the new resources in previously unexploited reservoirs: the ultrathin reservoir with only 0.4 to 0.8 m thickness and the 1- to 2-m low resistivity pay reservoir with an incoherent bottomwater level throughout the field.

A successful drilling strategy was developed that used double-step long horizontal drilling to cover dual thin layers from a single lateral for the ultrathin reservoir and a medium single lateral for the thin low resistivity pay reservoir. An integrated while-drilling application included directional electromagnetic and wellbore imaging technologies for rigorous geological well placement and spectroscopy and sigma for lithology and fluid identification for advance formation evaluation. This integrated application has enabled us to eliminate the need for pilot-hole wells, cover dual layers by single lateral, and avoid side tracks, thus improving efficiency and significantly saving the AFE budget; accurately place the well and significantly reduce the probability of erroneous lateral placement along the thin target layers and avoid drilling into water zone, thus optimizing reserve recovery; optimize the outline of future horizontal drain locations; and economically develop the new resources in previously unexploited reservoirs.
Pore Typing and Use of Capillary Bundles for Porefacies Constrained Saturation Model: A Case Study from Minagish Oolite Reservoir, Umm Gudair Field, Kuwait
Authors: Dutta Dipankar , Banerjee Tapan K. , Al Khalifa Nasser
Published: October 2013

Seventy nine HPMI (high pressure mercury injection) derived saturation height function curves are used to create nine different capillary bundles for Minagish Oolite carbonate reservoir. Each capillary bundle is tied up with its sedimentological and petrophysical attributes to create a discrete pore type/porefacies. The best pore type (Type 0) has well connected pore throat with lesser tortuosity as represented by very low entry point, low irreducible water saturation (Swirr) and wide plateau of the function curve. The worst one (Type 8) is very fine pore throats with high restriction of flow due to high entry point and very high irreducible water saturation. Good porefacies (Type 0, 1 and 2) represent mostly intergranular pore dominated samples, not much affected by subsequent cementation and dissolution. Intermediate pore types (Type 3,4 and 5) are found to have both primary intergranular and secondary solution rich pore spaces. The bad porefacies (Type 6,7 and 8) are either mud dominated or highly cemented rocks with restricted pore spaces. HPMI based poro-perm clusters are also used to create porefacies in the uncored wells and subsequently populated in 3D grid using variogram. Saturation height function of each representative capillary bundle is then used to tie the saturation value of individual porefacies along the well path in more than 250 wells. The newly constructed saturation grid is well tied with specific pore type of each facies and thus suitable to explain the fluid flow behavior within the reservoir. Well wise production behaviour and certain issues of anomalous production rate as well as water cut are satisfactorily explained through this workflow.
A Novel Workflow for Fracture Characterization and Well Placement Using BHI Data in WBM and OBM in Deep Unconventional Reservoirs of North Kuwait
Authors: Acharya Mihira N. , Al-Ajmi Saad A. , Al-Azmi Mejbel S. , Joshi Girija K. , Dashti Qasem , Al-Anzi Ealian H. , Chakravorty Sandeep , Darous Christophe
Published: October 2013

The tight deep carbonate reservoirs of Oxfordian age in North Kuwait consist of tight limestone interbedded with organic rich shale layers. The overall matrix porosity is generally very low and the production is mainly from fractures in the crestal part of main structures. Borehole images are routinely acquired in vertical to moderately deviated wells drilled with oil-base mud for fracture characterization.

For detailed fracture property evaluation, a highly deviated pilot hole was drilled with water-base potassium formate mud for the first time across the reservoir section and drill-pipe conveyed high-resolution electrical borehole image data was acquired. The upper half of the interpreted interval showed potential open fractures sets, NE-SW striking fracture set was most abundant. An advanced fracture segment extraction workflow was used to determine porosity and aperture of different fracture sets.

The first horizontal well was then drilled as a lateral in the target reservoir with oil-base mud restricting direct computation of fracture properties. The electrical and acoustic images in OBM indicated fracture concentrations at quite a few places along the horizontal well trajectory, the most conspicuous occurring at the zones where heavy mud losses were encountered while drilling. A 2D litho-structural model was constructed along the well trajectories using the dip data and open-hole logs to correlate finer carbonate and organic shale layers and fracture distribution across the layers. This workflow permitted extending fracture properties along horizontal well as well.

Finally, a high-resolution 3D structural model was constructed using outputs from previous workflows and data from two nearby vertical / less deviated wells. The final model showed a folded structure, which was absent in the existing model of the field. Thus the innovative workflow provides a means to generate an accurate structural and fracture model for the reservoir, integrating the fracture characteristics of the individual sub-layers with the main fracture corridors.
Application of Seismic Attributes in Estimating Gas Resources in Complex Fluvial Channel Reservoirs
Authors: Al-Duaij E.. , Al-Maraghi M.. , Zaid T.. , Klopf T..
Published: October 2013

The purpose of this paper is to show the reserve estimation procedures used by KUFPEC on the NW Shelf of Australia production license WA-49-L, which is currently under development as part of the Chevron's Wheatstone LNG project. The gas in the WA-49-L permit was discovered in a combination of structural and stratigraphic traps of a regional fluvial channel sand complex within the Triassic Mungaroo Formation. These channel sands contain gas trapped on a large structural ridge with up-dip terminations below a regional, angular unconformity and overlain by the Cretaceous Muderong Shale. Some of the deeper channel sands are trapped against the bounding fault of the ridge. These channel sands are stacked as a result of amalgamation of numerous channels, with the individual sand thickness of up to 60 meters but typically in the 15 to 30 meters range. These channel sands are discrete with individual gas-water-contacts, and clearly visible on seismic and inversion data as low impedance, Class 3 AVO (amplitude versus offset) anomalies.

The estimation of gas resources is delineated by 20 wells drilled through April 2011 on WA-49-L. Limitations of the seismic frequency content result in channel thicknesses of less than 5 meters not being visible. Seismic inversion attributes are used to estimate gas sand probability, sand thickness and porosity. Rather than using large scale net-to-gross assumptions commonly used in the industry for reserves calculations, KUFPEC used maps of individual sand bodies based on the inversion impedance amplitudes and gas sand probability (GSP) attributes to compute each sands' likely range of resources values.
Improved Desalting of Challenging Crude Slates
Authors: Sellman Erik , Mandewalkar Pavan , Sams Gary
Published: October 2013

Crude slates containing a blend of traditional and heavy crude oil are challenging to desalt in most refineries.

In addition to the higher crude oil viscosity and reduced oil / brine density difference, heavy crude oil also provides additional challenges in the form of higher crude oil conductivity and solids stabilized emulsions. Blended oils often have a higher solids content which can stabilize rag layers inside the desalters.

Many refineries use AC type electrostatic technology operating at line frequency, 50 or 60 Hz. Conventional AC desalters provide limited voltage gradients and are not efficient for treating conductive crude oils.

Advancements in electrostatic desalters have resulted in desalters providing stronger electrostatic forces and improved conditions for coalescence of brine droplets.

Computational fluid dynamics (CFD) has also provided a better understanding of the oil and brine flow inside refinery desalters, which has lead to the use of improved internals which provide a better fluid distribution, elimination of recirculation areas and allowing higher flow rates at constant BS&W and PTB.

More efficient desalting of crude oil in refineries can provide the following benefits: –OPEX:○opportunity to process higher volumes of cheaper opportunity crude oil○reduced volume of wash water○lower operating temperature○lower demulsifier dosage○higher desalter uptime–CAPEX○use of smaller desalters (only applicable for new desalters)○reduced transportation cost

This paper describes new enhanced electrostatic desalting technologies, including case studies.
Full Field History Matching For Chemical Flooding With The Adjoint Method
Authors: Douma Sippe G. , Abu-Shiekah Issa , Kindi Zakariya
Published: October 2013

Enhanced Oil Recovery is firmly established in the hydrocarbon maturation plans of PDO and Shell with successful ongoing thermal and polymer field developments and many novel methods being piloted. The current developments and trials undergo in-depth study to leverage the learnings for portfolio-wide application. In optimizing a current or derisking a future EOR development, understanding of the reservoir is key and more crucial than during primary and secondary development because of the complexity of the processes and higher costs involved.

In this paper the use of an advanced history matching technique for improving reservoir understanding is discussed in the context of full field chemical flooding. A powerful feature of the Shell proprietary reservoir simulator is the availability of the so-called adjoint method which allows history matching of gridblock parameters such as permeability and porosity in an efficient and effective manner. The method is applied in a workflow coined model maturation (Joosten & Altintas (2011)), where the local permeability updates are used to highlight deficiencies in the geological model (e.g. missing faults, aquifer locations, pinch outs).

In this particular study the adjoint method improved the pattern match significantly but more importantly revealed the need for fine scale local geological features, confirmed by other data. The improved models describe the observed polymer behavior in line with our theoretical and analytical understanding of polymer flooding. The study showed that understanding EOR processes can only be done after a proper understanding of the reservoir.
Stochastic Optimization of Cyclic Steam Stimulation in Heavy Oil Reservoirs
Authors: Azad Madhar Sahib , Alnuaim Sami , Awotunde Abeeb A.
Published: October 2013

Cyclic Steam Injection (CSS) has been used in the industry to increase the recovery factor and production rate from heavy oil reservoirs. CSS is multi-cycled steam recovery process with three stages and five operational parameters (injection rate and its duration, soak time, production rate and its duration) in each cycle. Determining the optimal values of the operational variables in each cycle, for the existing reservoir conditions is challenging. The difficulty stems from the fact that these parameters cause significant changes in reservoir fluid flow, reservoir behavior and recovery performance during the project duration. Ability to effectively determine the best values of these parameters is expected to increase the recovery efficiency and the profitability of the project.

In practice, the parameters of cyclic steam stimulation are often determined by running limited sensitivity studies on some or all the parameters. Such sensitivity studies are however very limited in scope and cannot explore the entire domain of interest. A more efficient method to estimate the optimal parameters of the CSS is to perform automatic optimization using an effective stochastic optimization algorithm. In this work, we propose the use of stochastic optimization to estimate the parameters of CSS. Three different CSS models were developed with three well types (vertical, horizontal and inclined wells). The operational parameters are extremely interdependent in CSS which has mulitiple drive mechanisms. The need for global search is imperative to find the best operating parameters in each cycle. Covariance Matrix adaption Evolution Strategy (CMA-ES) was used to optimize the operational parameters. The project net present value (NPV) was used as the objective function in the optimization process. Results showed that the NPV can be increased significantly when all the operational variables of CSS are optimized. This signifies the importance of simultaneous optimization of soak time, cycle length and rates. The results also showed that the vertical well model gave a higher NPV than the other two well models. The horizontal well model gave the lowest NPV.
New Approach to Validate History Matching Process
Authors: Abdel-Rahman M. R. , Dharmawan M. A. , Abdelrahim R.. , Akhtar M. N. , Mekki N.. , Al-Namlah S. A.
Published: October 2013

Conducting a history matching process is the most challenging and time consuming phase for reservoir simulation domain. It is worthy to invest more efforts to introduce new approaches to validate history matching results. This to guaranty the 3D model calibration has been adapted to adequate level that will minimize associated risk for the proposed forecast that completely rely on the history matching quality.

This paper is describing a new approach for validating history matching results. It describes new workflow that is used to integrate all historical information comes from field surveillance and shows change of fluid distribution over field production history, e.g. observation of oil water contact encroachment, water coning, etc.

Petrel™ as a 3D modeling package is used to integrate all of these information in automated way to build conceptual 3D fluid distribution models at selected time increments that represent the field production history. The workflow has two main steps, 1st to use geo-statistical approach to interpolate available fluid change surveillances at well level to build fluid contact surfaces at selected time increments. 2nd step, Petrel™ will use each contact surface individually to build corresponding 3D conceptual fluid distribution model to describe fluid profile in 3D at a time.

These conceptual models will simulate the overall mechanism of subsurface fluid movements over the production history based on the available historical data. By the end, the generated conceptual 3D fluid distribution models can be used to validate the fluid saturation models come from any finite difference simulator. It will do help to have better understanding of field performance in response to fluid contact change. In additional; It can guide a preliminary plan to propose infill wells for field development plans.

This paper shows a detailed workflow of a mechanistic study to cover this new approach of validating the History Matching process and shed a light on the challenges and limitations of this new approach.
Differences in fatty acid composition of meat between naked neck and two commercial broiler chicken breeds
Authors: Pavlovski Z. , Skrbic Z. , Stanisic N. , Lilic S. , Hengl B. , Lukic M. , Petricevic V.
Published: October 2013

Chicken meat from intensive broiler production have different quality
compared with meat from native chicken breeds and chicken from a free range
production system. The aim of the present study was to evaluate differences
in fatty acids content of meat of Naked Neck chickens rared in free range
system and two commercial broiler breeds (Cobb 308 and Hybro G+) reared in
conventional production system. The trial involved 100 chickens per group.
Fattening period lasted 42 days for conventional system and 84 days for free
range system. Breast meat of Naked Neck chicken had statistically more 16:0
content compared with Cobb 308 (p?0.05), where in thigh meat the highest
content of 16:0 was determined in Hybro G+ breed. Differences for fatty acids
composition of breast meat between breeds were also established for 14:0,
17:0, 18:0, 16:1, 18:1, 18:2, 20:2, 22:1 and 22:5 fatty acid. The Naked Neck
group showed the highest (p?0.05) percentage of SFA and the Cobb 308 showed
the lowest in breast meat. Thigh SFA were also significantly different
(p?0.05) between breeds, where Naked Neck chickens had the lowest and Hybro
G+ the highest values. Breast MUFA were higher in Hybro G+ than in Naked Neck
or Cobb 308 chickens, and thigh MUFA content had opposite trend and it was
the lowest in Hybro G+ chicken. In conclusion, free ranged Naked Neck
chickens have been shown to have significant different fatty acid composition
compared with broiler chickens reared in conventional system.
Quality parameters and pattern recognition methods as a tool in tracing regional origin of multifloral honey
Authors: Lazarevic Kristina , Trifkovic Jelena , Andric Filip , Tesic Zivoslav , Andjelkovic Ivan , Radovic Dejan , Nedic Nebojsa , Milojkovic-Opsenica Dusanka
Published: October 2013

The characterization of multifloral honey regarding the mineral composition,
sugar content and basic physicochemical properties has been done. The total
of 164 honey samples was collected from six regions of Serbia during 2009
harvesting season. Univariate data analysis (descriptive statistics and
analysis of variance), geographic information system and pattern recognition
methods (principal component analysis and cluster analysis) have been
performed in order to identify geographical origin of honey. The content of
Mg, K, and Cu, electrical conductivity, and optical rotation were established
as useful indicators in tracing regional differences between honey samples.
Samples originated from Zlatibor region were clearly distinguished from those
from the rest of Serbia showing higher K and Mg content, as well as higher
values of optical rotation, electrical conductivity, and free acidity. The
influence of the soil composition, and climate conditions, as well as the
presence of particular flora on the honey composition is stressed out. The
modeling of geographic origin of honey has been attempted by the means of
linear discriminant analysis.
Comparison of localisation of α- and β-oestrogen receptors in posterior part of the piriform cortex in rabbit males
Authors: Krakowska Izabela , Lonc Grzegorz , Matysek Małgorzata , Kupczyńska Marta
Published: October 2013

The aim of the study was to compare the immunoreactivity and distribution of two kinds of oestrogen receptors within the nerve tissue of the posterior part of the piriform cortex, as well as their localisation within nerve cells. The studied material consisted of 12 brains of sexually mature rabbit males weighing 3-4 kg. In order to prove the presence of α and β receptors, Er-α and Er-β antibodies were used. The examinations showed the presence of Er-α and E-rβ receptors in all layers of the piriform cortex, however, mainly in the IInd and IIIrd layer. The reaction occurred in the nucleus and cytoplasm of neurons. The obtained results can imply the influence of oestrogen on the functions of the examined brain area in rabbits, which in human is responsible for perception and categorisation of odour.
Influence of Preparation Method of Spirogyra Sp. Algae on their Sorption Capacity
Authors: Rajfur Małgorzata
Published: October 2013

The influence of the preparation method of samples on the zinc ions sorption parameters in Spirogyra sp. algae was analysed. The Zn2+ sorption process from the salt solutions of this analyte was carried out in static conditions. The carried out analyses results show that the method of algae samples preparation for analyses (thermal drying, freeze drying, samples conditioning in demineralised water) and storage period influence their sorption capacity. On the basis of the carried out research of the metal sorption kinetics in live and prepared algae samples, it was found that the equilibrium is achieved after approximately 30 min. In the experiment conditions, 56% of metals are sorbed in live algae during the first 15 min. Approximately 17 and 65% of zinc ions present in the dilution accumulated in thermally dried and freeze dried algae samples respectively after 30 min of the process. It was confirmed that conditioning of the algae samples in demineralised water, prior to the sorption process, increases its efficiency. In order to define sorption capacity of freeze dried Spirogyra sp. algae, the Langmuir isotherm model was applied. It was found out that algae absorb heavy metals in proportion to their content in a solution, in which they were immersed. The sorption capacity of freeze dried Spirogyra sp. algae and zinc, defined with the use of the Langmuir isotherm, shows considerable imprecise result. Evident influence of hydrogen cations on zinc concentrations in algae and in the solution in the state of equilibrium was found out.
Trace-fossil assemblages with a new ichnogenus in “spotted”
Authors: Šimo Vladimír , Tomašových Adam
Published: October 2013

Highly-bioturbated “spotted” limestones and marls (Fleckenmergel-Fleckenkalk facies) of the Early Jurassic, which were deposited in broad and recurrent deep-shelf habitats of the Northern Tethys, are characterized by rare benthic carbonate-producing macroinvertebrates. To address this paradox, we analyse trace-fossil assemblages in a ~85 m-thick succession of Pliensbachian spotted deposits (Zliechov Basin, Western Carpathians). They are dominated by infaunal and semi-infaunal deposit-feeders, with 9 ichnogenera and pyritized tubes of the semi-infaunal foraminifer Bathysiphon, being dominated by Chondrites, Lamellaeichnus (new ichnogenus), and Teichichnus. Lamellaeichnus, represented by a horizontal basal cylindrical burrow and an upper row of stacked convex-up gutters, was produced by a mobile deposit-feeder inhabiting shallow tiers because it is crossed by most other trace fossils. We show that the spotty appearance of the deposits is generated by a mixture of (1) dark, organic-rich shallow- and deep-tier traces (TOC = 0.16-0.36), and (2) light grey, organic-poor mottled or structurless sediment (TOC = 0.09-0.22). The higher TOC in shallow-tier burrows of Lamellaeichnus demonstrates that uppermost sediment layers were affected by poor redox cycling. Such conditions imply a limited mixed-layer depth and inefficient nutrient recycling conditioned by hypoxic bottom-waters, allowed by poor circulation and high sedimentation rates in depocenters of the Zliechov Basin. Hypoxic conditions are further supported by (1) dominance of trace-fossils produced by infaunal deposit feeders, (2) high abundance of hypoxiatolerant agglutinated foraminifer Bathysiphon, and (3) high abundance of Chondrites with ~0.5 mm-sized branches. Oxygen-deficient bottom-conditions can thus simultaneously explain the rarity of benthic carbonate-producing macroinvertebrates and high standing abundance of tolerant soft-shell and agglutinated organisms in spotted deposits.
Real Estate Mass Appraisal in Selected Countries – Functioning Systems and Proposed Solutions
Authors: Barańska Anna
Published: October 2013

In this paper, the systems of real estate mass appraisal in some selected European countries will be discussed, in comparison with those of individual countries on other continents, in terms of similarities and differences in law, institutional scope and subjects responsible for its execution. With selected countries serving as an example, the practical aspects of operating the real estate owners’ taxation system will be discussed as well the data acquiring process, considered price-making factors, proceeding methodology and circumstances taken into account in real estate cadastral valuation, giving consideration to national specificity.
Fragmented deformations of primitive multiple curves
Authors: Drézet Jean-Marc
Published: October 2013

A primitive multiple curve is a Cohen-Macaulay irreducible projective curve Y that can be locally embedded in a smooth surface, and such that Y red is smooth. We study the deformations of Y to curves with smooth irreducible components, when the number of components is maximal (it is then the multiplicity n of Y). We are particularly interested in deformations to n disjoint smooth irreducible components, which are called fragmented deformations. We describe them completely. We give also a characterization of primitive multiple curves having a fragmented deformation.
The combinatorial derivation and its inverse mapping
Authors: Protasov Igor
Published: October 2013

Let G be a group and P G be the Boolean algebra of all subsets of G. A mapping Δ: P G → P G defined by Δ(A) = {g ∈ G: gA ∩ A is infinite} is called the combinatorial derivation. The mapping Δ can be considered as an analogue of the topological derivation d: P X→ P X, A ↦ A d, where X is a topological space and A d is the set of all limit points of A. We study the behaviour of subsets of G under action of Δ and its inverse mapping ∇. For example, we show that if G is infinite and I is an ideal in P G such that Δ(A) ∈ I and ∇(A) ⊆ I for each A ∈ I then I = P G.
Small deviations of iterated processes in the space of trajectories
Authors: Frolov Andrei
Published: October 2013

We derive logarithmic asymptotics of probabilities of small deviations for iterated processes in the space of trajectories. We find conditions under which these asymptotics coincide with those of processes generating iterated processes. When these conditions fail the asymptotics are quite different.
A HOLISTIC APPROACH TO GENERAL AVIATION AIRCRAFT STRUCTURAL FAILURE PREVENTION IN AUSTRALIA
Authors: Kourousis Kyriakos I.
Published: October 2013

Ageing aircraft are becoming a major issue in the general aviation (GA) industry, both in terms of safety and maintenance and support cost. Ensuring a sound structure is considered one of the primary challenges in this area, it is, therefore, attracting the attention of the regulating authorities. The Civil Aviation Safety Agency (CASA) has taken a mixture of actions to tackle the various issues related to the diverse Australian GA ageing aircraft fleet. Further efforts focus on increasing the awareness of the different parties engaged in aircraft operations, maintenance and design, as well as quantification of the associated risk. In this frame a holistic approach is proposed to cover the various aspects, emphasizing the use of cost-effective structural health monitoring (SHM) systems and web-based education and information dissemination on ageing aircraft issues.
CFD ANALYSIS OF TERRAIN INDUCED TURBULENCE AT KRISTIANSAND AIRPORT, KJEVIK
Authors: Rasheed Adil , Sørli Karstein
Published: October 2013

The paper presents the finding of a study conducted in order to analyse the characteristics of flow in a real complex terrain in the vicinity of the Kristiansand Airport (Kjevik), Norway. The paper starts with a brief description of the governing equations, their numerical discretization and the safety criteria used by the aviation industry to classify turbulence as mild or extreme. Directional dependence of the flow characteristics in the region is studied followed by an attempt to validate the experience of the pilots operating in the region.
Faculty Experience of Online Teaching
Authors: Khanova Julia
Published: October 2013

Online education is growing rapidly and outpacing research efforts in this area. Online teaching in particular has received little research attention. Grounded in existing literature and empirical research, this chapter aims to describe the key dimensions of the faculty experience of preparing and teaching online courses. The differences between online and traditional teaching are highlighted, emphasizing time/effort cost, technology and support needs, as well as the relationship between online teaching technology and pedagogy. The shift in faculty role is discussed. Special attention is given to using various Web resources for online teaching and the impact of this trend on library services. Real-life examples and direct quotes from faculty who teach online are used to illustrate each of the themes and suggest directions for future research.
Bringing the Librarian to Online Courses
Authors: Weissman Nancy , Swan Karen
Published: October 2013

This chapter explores the way one librarian is bringing real-time, personalized instruction to students in online classes to engage them dynamically with their library and provide the best possible learning experiences. The discussion is grounded in the Community of Inquiry (CoI) framework, perhaps the most widely accepted model of online learning, and suggests that learning online is supported by three “presences”: cognitive, social, and teaching. The model and each presence are discussed first, followed by virtual library instruction being introduced. Virtual library instruction is seen as the way to ensure equity in providing library services for fully online students and, specifically, information literacy instruction. The authors discuss how virtual librarians can use cognitive, social, and teaching presence to make their instruction more effective. Specific tools, strategies, and best practices are presented, as are general recommendations for similar development.
Assessment of Student Learning Outcomes in Distance Education
Authors: Gregory Vicki L.
Published: October 2013

Student Learning Outcomes (SLOs) are becoming the norm for all types of accreditation decisions by regional and specialized agencies. SLOs and student assessment norms and best practices are described, as well as a path to establish SLOs. Analyzing and using the data collected about student assessment to enrich student learning is also described. Special attention is given to LIS instruction, but several comparisons to other disciplines are also made.
Community Detection and Profiling in Location-Based Social Networks
Authors: Wang Zhu , Zhou Xingshe , Zhang Daqing , Guo Bin , Yu Zhiwen
Published: October 2013

Due to the proliferation of GPS-enabled smartphones, Location-Based Social Networking (LBSNs) services have been experiencing a remarkable growth over the last few years. Compared with traditional online social networks, a significant feature of LBSNs is the coexistence of both online and offline social interactions, providing a large-scale heterogeneous social network that is able to facilitate lots of academic studies. One possible study is to leverage both online and offline social ties for the recognition and profiling of community structures. In this chapter, the authors attempt to summarize some recent progress in the community detection problem based on LBSNs. In particular, starting with an empirical analysis on the characters of the LBSN data set, the authors present three different community detection approaches, namely, link-based community detection, content-based community detection, and hybrid community detection based on both links and contents. Meanwhile, they also address the community profiling problem, which is very useful in real-world applications.
ISW
Authors: Zeng Jinlong , Zheng Guifeng
Published: October 2013

Content location in unstructured peer-to-peer (P2P) networks is a challenging problem. In this paper, the authors present a novel Interest-based Small World (ISW) network to address the problem, by constructing a cluster overlay in the unstructured P2P network based on the small world paradigm and user interest. There are many attractive properties of a small world network, such as low average hop distance and high clustering coefficient. Interest locality can improve the awareness of user’s indeed intentions. The authors’ scheme combines their advantage to create a better solution. The simulation results show that our scheme outperforms other schemes significantly.
A Performance Prediction Method with an Equation-Based Behavioral Model for a Single-Bit Single-Loop Sigma-Delta Modulator
Authors: Lee Shuenn-Yuh , Hong Jia-Hua
Published: October 2013

An equation-based behavioral model has been developed to predict the real performance of a single–loop single-bit Sigma Delta Modulator (SDM). By using this prediction flow, not only can the circuit specifications be acquired, including the gain, bandwidth, slew rate of the OPAMPs, and the capacitor value in the switched-capacitor circuits, but the real performance of the SDM can also be predicted. The switched-capacitor circuits according to the required circuit specifications are employed to design a fourth-order feed-forward (FF) SDM with an over-sampling ratio (OSR) of 64 and a bandwidth of 10kHz using a TSMC 0.35µm CMOS process. The measurement results reveal that the SDM with an input frequency of 2.5kHz and a supply voltage of 3.3V can achieve a dynamic range of 90dB and a spurious-free dynamic range (SFDR) of 85dB under the signal bandwidth of 10kHz and a sampling frequency of 1.28MHz, respectively. The precision of the equation-based behavioral model has been validated by experimental measurements, and its inaccuracy is less than 4%.