bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Evaluation of LWD Resistivity Logs in Highly Deviated and Horizontal Wells in Saudi Arabia
Authors: Anguiano-Rojas Pedro , Seifert Douglas J. , Bittar Michael , Eyuboglu Sami , Tang Yumei , Donderici Burkay
Published: September 2013

With the recent advancement of directional drilling technology and the use of rotary steerable systems, more deviated and horizontal wells are being drilled and evaluated around the world and especially in Saudi Arabia. In these complex reservoirs, logging while drilling (LWD) wave propagation technology allows accurate geosteering and well placement. Such a technology often exhibits boundary related artifacts (horns) at formation boundaries between beds having different resistivities, particularly where the borehole penetrates formations at an angle. This makes resistivity interpretation difficult and creates a challenge for determining true formation resistivity that is essential for determining hydrocarbon saturation.

This paper presents a processing methodology for the elimination and reduction of horns and shoulder bed effects. Logs processed using this method are more accurate and easier to interpret. This new technique solves the forward and inverse problems using a simplified approach. The forward problem is solved using a fast analytical technique that generates synthetic logs. The inverse problem is solved using the forward problem solution iteratively and minimizing a cost function that measures the discrepancy between the generated synthetic logs and the field data in a Gauss-Newton fashion.

Data processing and inversion of examples from fields in Saudi Arabia are presented to illustrate the usefulness of this methodology. For the examples, the values of formation resistivity and distances to bed boundaries are obtained. These results indicate that the processing method provides a reliable technique for evaluating the true formation resistivity of LWD logs in deviated and in horizontal wells for both well placement and formation evaluation.
Automatic Integration of Streamline Information in Finite Difference Simulation during Optimization to Enhance History Matching
Authors: Siu Alan L. , Al-Turki Ali A. , Al-Zawawi Ahmed S. , Al-Nahdi Omar A.
Published: September 2013

Matching water cuts of production wells is one of the most challenging tasks in the history matching process. When conducting history matching with a finite difference simulator, one of the challenges is how to define a suitable region for the permeability modifier to obtain a good match, and yet, retain major geological description. In the case of large models, the presence of several wells in a region where permability is adjusted makes simultaneous matching for these wells almost impossible.

Commercial streamline simulators are best in reducing the mismatch in water cuts; however, it is cumbersome to include other uncertainty parameters such as water-oil contact, relative permeability, pressure-volume-temperature data, etc., during the optimization process. To combine the power of finite difference simulators and streamline technology, an in-house developed reservoir simulator was linked to a customized streamline tracing software package. This solution is capable of generating streamlines that represent a snapshot of the flow pattern within the reservoir, and providing well drainage region information and injector-producer relationships.

This paper presents an automatic process in which the reservoir simulator is run via the control of a commercial optimizer, the simulation results are transferred to the streamline tracing package, which also tags the simulator cells to be modified by the optimizer without running a full streamline simulation. The optimizer then uses a global minimization method to fine-tune the permeability modifiers for reducing the water cut errors. This approach was verified by using two synthetic models in which the solution is known. Excellent results were obtained. Therefore, this approach makes it possible to employ the power and flexibility of finite difference simulators and optimization algorithms, with the crucial fluid flow information provided by streamline technology.
Holistic Approach in Deriving the Optimum Value of Smart Completions in MRC Wells
Authors: Rowaihy Feras , Pham Tony
Published: September 2013

The technology of smart completions has gained a big momentum in oil and gas industry and marked a significant paradigm shift in terms of optimizing production, enhancing sweep per lateral, managing water production and prolonging wells’ life. HRDH Increment-III is Saudi Aramco’s first Increment that was initially developed with intelligent field technology and maximum reservoir contact multi laterals wells equipped with smart completions. Field performance was put under detailed evaluation where positive results acted as a basis for further implementation of such technologies in other fields in Saudi Aramco. While objectives of smart completion were fully achieved with excellent sustainability in maintaining oil production plateau under very low water cut that was beyond initial expectations, Haradh team experience with smart completions indicated that benefits could be further enhanced by tackling identified challenges with the initial design to further enhance the ultimate value of such technologies.

This paper describes a case study that illustrates in details, Haradh experience with optimizing production from a Maximum Reservoir Contact well. This entails completion design enhancement to add more pressure data points into the system and then the holistic approach taken to achieve the ultimate value of the smart completions by integrating each lateral’s reservoir characterization analysis, production data and pressure data to select the right down hole valves adjustments. Leveraged knowledge from this case provides an insight into smart completion capabilities and utilization strategies to maximize the values from these technolgies.
Zero Oil Flaring Concept and Implementation in Saudi Aramco Offshore Fields
Authors: Al-Jamal Abdulrahman A. , Kilany Khaled A. , Riza Iskandar X. , Yateem Karam S. , BoKamseen Yaseen A.
Published: September 2013

The main objective of the zero flaring concept in Saudi Arabian offshore fields is to further fully comply with the environmental regulations and to continue ensuring zero hydrocarbon discharge to the environment during well cleanup, through zero flaring practice without compromising safety. The first implementation was carried out back during the last decade with workover operation in offshore field’s sweet crude and then extended to sour fields with an excellent success1, 2. The workover wells that were cleaned up utilizing this practice resulted with zero hydrocarbon discharge to the atmosphere. The same concept of well cleanup was considered for new drilling wells, therefore the new platforms that are currently under drilling or those that will be drilled and completed in the future have to accommodate this technique. The current plan is to modify in-water platforms for zero oil flaring technique, however, the needed zero oil flaring facilities for all future platforms will be installed on the onshore fabrication yard to optimize operational logistics.

The required facilities to accommodate the zero oil flaring practice on new drilling offshore installed platform include constructing of a 4" jumper line and running inline inspection (ILI) of the subsea flow line to the tie-in platform (TP). The zero flaring operations can be done once the jumper line has been installed and ILI of the subsea flow line to the TP has been performed as part of the subsea flow line mechanical certification. Upon completing drilling on the platform, the portable skid on the drilling rig is connected to the jumper line, and then, the wells are flowed for cleanup through the flow line to the TP and then through the trunkline to the GOSP.
Assessment of Uncertainty in Porosity Measurements Using NMR and Conventional Logging Tools in Carbonate Reservoir
Authors: Kharraa Hamad S. , Al-Amri Meshal A. , Mahmoud M. A. , Okasha T. M.
Published: September 2013

Porosity is an important volumetric parameter used to estimate the reserves for oil and gas reservoirs and as an input for reservoir simulation. Porosity can be classified into effective porosity (interconnected pores) and ineffective porosity (isolated pores), while total porosity (ϕT) is defined as the sum of effective porosity and the porosity associated with Clay Bound Water. In clean formations, total porosity is equal to effective porosity, whereas in shaly formations it must be corrected for clay effect. Formation porosity can be determined using several methods. These methods include: measuring actual porosity in the core laboratory, Computerized Tomography (CT) scan, neutron-density logging, sonic tools and Nuclear Magnetic Resonance NMR logging tools.

The NMR logging is unique compared to all other methods since it is independent of the reservoir lithology. It can be used to estimate the reservoir porosity directly without the knowledge of matrix lithology. On the other hand, conventional logging such as neutron-density and acoustic depend strongly on lithology which might yield incorrect porosity measurement. Several studies have been conducted to estimate porosity for both sandstone and carbonate reservoirs using different logging tools, however, determining porosity is a challenge in complex and unconventional lithologies. In sandstone, the presence of shale and clay minerals will affect the response of all porosity tools. Carbonate is even more complicated than sandstone due to its heterogeneity and triple porosity system (pores, vugs, and fractures). In addition, the assessment of porosity measurements accuracy using NMR logging will be considered in this study. An attempt will be made to develop an empirical correlation from NMR data to obtain reliable porosity estimation.

In this work, case studies will be presented using NMR logging tool to show how NMR reduces the uncertainty of porosity measurements in carbonate reservoirs compared to other conventional logging tools, which will improve reserves estimation. The study will also show the effect of impurities in the carbonate formation porosity measurements by conventional and NMR logging methods compared to stress core porosity by graphical means. Results of this study showed that a clear criterion to divide the formations into dolomitic and clean formation (pure limestone) should be established to get more accurate result. In the dolomitic formation, Neutron-Density showed the least AARE of 40.2% compared to 84% for the NMR tool and 174% for the sonic tool. However, for clean formation NMR tool was the most accurate tool with AARE of 10% compared to 14.3% for N-D tool and 42.3% for sonic tool.
Silver nanoparticle removal from drinking water: flocculation/sedimentation or filtration?
Authors: Lawler Desmond F. , Mikelonis Anne M. , Kim Ijung , Lau Boris L. T. , Youn Sungmin
Published: September 2013

Silver nanoparticles are used in a wide variety of consumer products and are therefore rapidly becoming ubiquitous in the natural environment; they can be expected to be found in the natural waters used as drinking water supplies. This research investigated whether such particles could be expected to be removed in conventional water treatment plants such as flocculation and filtration. Both flocculation and granular media filtration experiments with citrate-capped silver nanoparticles were performed at different ionic strengths and in the presence and absence of natural organic matter. The results were generally consistent with theories of particle destabilization that have been developed for larger particles (greater than 1 μm), suggesting that silver nanoparticles are likely to be removed in conventional treatment processes.
Characterization of hydraulically reversible and irreversible fouling species in ultrafiltration drinking water treatment systems using fluorescence EEM and LC–OCD measurements
Authors: Peiris R. H. , Jaklewicz M. , Budman H. , Legge R. L. , Moresoli C.
Published: September 2013

The application of the fluorescence excitation-emission matrix (EEM) approach and liquid chromatography–organic carbon detection (LC–OCD) analysis for the characterization of hydraulically reversible and irreversible fouling species, extracted from hollow fiber ultrafiltration (UF) membranes used in drinking water treatment, was demonstrated. Hydraulically reversible and irreversible fouling species were extracted from two pilot UF membrane systems operated in parallel with lake water as the feed. Two membrane cleaning protocols, hydraulic- and chemical-based (NaOCl and citric acid) cleaning, were considered. Colloidal/particulate matter together with protein-like and metal species in water appeared to contribute to the formation of a hydraulically removable fouling layer on the membranes. Hydraulically irreversible fouling, in contrast, was impacted considerably by humic substances (HS) and protein-like matter. The formation of an irreversible fouling layer was also likely influenced by interactions between the colloidal/particulate matter and metal species together with HS and protein-like matter. LC–OCD analysis revealed the presence of predominant levels of lower molecular weight HS-like matter – compared to the HS-like matter commonly present in lake water – in the citric acid extracted foulant fraction. The permeability loss due to hydraulically irreversible UF fouling was considerably greater than the permeability loss due to hydraulically reversible UF fouling. A permanent permeability loss (∼25–35% of the initial permeability) was present even after the application of considerably strong chemical cleaning protocols on both pilot systems. This study indicated that the fluorescence EEM approach can be applied for monitoring and characterization of membrane cleaning procedures and as a potential diagnostic tool for assessing the effectiveness of hydraulic- and chemical-based cleaning protocols employed in UF drinking water treatment operations using rapid off-line measurements. On the other hand, since the LC–OCD analysis technique is a comparatively time consuming method, it may be used for verification of the fluorescence EEM-based results of the foulant fractions.
Recent trends in microorganism-related off-flavor problems in drinking water treatment systems in Japan
Authors: Kishida Naohiro , Konno Yoshiaki , Nemoto Kentaro , Amitani Taisuke , Maki Akihito , Fujimoto Naoshi , Akiba Michihiro
Published: September 2013

In this study, recent trends in off-flavor problems were investigated by a nationwide questionnaire targeting 142 drinking water treatment plants (DWTPs) in Japan. The results indicated that 46 of 142 DWTPs in Japan had experienced off-flavor problems in a recent 5-year period. Cyanobacteria such as Anabaena spp., which produce musty/earthy odors, are the most common microorganisms that were presumed by DWTPs to be responsible for producing off-flavor compounds. Other microorganisms, such as diatoms, chrysophytes, and actinomycetes, are also involved in producing off-flavors. To eliminate off-flavor compounds, most facilities use powdered activated carbon treatment, which greatly increases operational costs. In addition, an interview survey targeting one typical DWTP affected by off-flavor problems was performed to investigate operational costs increased by off-flavor problems and the effects of water temperature on the occurrence of off-flavors. The operational costs when an off-flavor problem occurred were 2.9 times those when the problem did not occur, mainly due to the cost of powdered activated carbon. Therefore, off-flavors are a very serious problem in water treatment systems in Japan. The interview survey suggested that water temperature would be one of the important factors influencing the occurrence of off-flavor compounds in water sources.
An improved method for determining HNMs in drinking water
Authors: Huang F. Q. , Ruan M. Y. , Yan J. D. , Hong H. C. , Lin H. J. , Xiong Y. J.
Published: September 2013

Halonitromethanes (HNMs) in drinking water are increasingly becoming a public concern due to their high health risks, so development of a sensitive method for their analysis has become a priority. Liquid–liquid extraction (LLE) method is dominantly used in current studies regarding HNMs. However the sensitivity is far from ideal. The present study aims to investigate the factors that may influence the extraction efficiency during HNM analysis by LLE method, and as a result develop a more sensitive extraction method for HNM determination. Results showed that the dose of sodium sulfate exerted the most significant influence, followed by copper sulfate, while the pH and manual shaking times have little effect. Under the suitable conditions (for extracting HNMs in 45 mL water: pH = 3.5–5, CuSO4 = 1.0 g, Na2SO4 = 6 g, shaking times = 120–180), the correlation coefficients (r) of the calibration curves for nine HNMs were all more than 0.9925. The method detection limit (MDL) ranged from 0.017 to 0.217 μg L−1 with an average of 0.076 μg L−1, which was dominantly lower than the method reported. The recovery (spiked blank samples: 98–108%; spiked tap water: 81–120%) and precision (relative standard deviation: 0.46–6.72) also showed good reliability and reproducibility of the method. Finally, the developed method was applied to the determination of HNMs in real water samples.
Integrated watershed management efforts: case study from Melen Watershed experiencing interbasin water transfer
Authors: Ozturk I. , Erturk A. , Ekdal A. , Gurel M. , Cokgor E. , Insel G. , Pehlivanoglu-Mantas E. , Ozabali A. , Tanik A.
Published: September 2013

Istanbul is a megacity with a population of over 13 million. Due to experienced droughts and population growth in the city, interbasin water transfer from Melen Watershed was considered as the most feasible alternative to supply water that can compensate for water demand in the future. This decision changed the beneficial use of the Melen Watershed from irrigation water supply to drinking water supply and necessitated extensive pollution prevention measures to comply with the new water quality requirements. A Watershed Protection Action Plan was developed for the sustainable management of Melen Watershed. The action plan included measures concerning wastewater management, diffuse pollution management, solid waste management and water quality monitoring. In this paper, proposed protection actions in the plan are provided together with the activities realized so far. In addition, the changes made by the authorities during implementation of the plan are presented. The proposed Watershed Protection Action Plan as approved by the government is one of the first examples in Turkey, where watershed-based planning of water resources is implemented instead of administrative boundary-based management.
Removal characterization of 133Cs and 127I in a water treatment process using a laboratory scale experiment
Authors: Lee Hee Suk , Lee Jeongyup , Yoon Byengsuk , Yim Youjin , Choi Ilhwan , Cho Hyukjin , Lee Songhee , Baik Kyounghee , Park Ju Hyeon , Huh Yu Jeong
Published: September 2013

Due to the tragic disaster that happened in Japan and crippled the Fukushima nuclear power plant, serious concerns have been raised regarding the contamination of drinking water as a result of the radioactive materials that were released. Even though the quantities of radioactive material in rain were relatively low, people were concerned about the drinking water. Therefore, there is a need to know the removal efficiency of the unit process of water treatment and to prepare a safety plan to protect the public's health from radioactive materials. In this study, the laboratory scale removal rates were estimated for the coagulation/flocculation, adsorption, and ion exchange processes. The reference standard materials which are stable elements, Cesium-133 (Cs-133) and Iodine-127 (I-127), were used for the typical and advanced water treatment processes at the laboratory scale. For the coagulation/flocculation process, three major coagulants were assessed for this process. However, the removal rates of this process were low. For the adsorption process, powdered activated carbon and zeolites were investigated. The powdered activated carbon showed insignificant removal rates for both reference materials. However, synthetic zeolite was an effective process for Cs-133, and the ion exchange method showed high removal rates for both Cs-133 and I-127.
Comparison between Rapid ID 32 Strep System, Matrix Assisted Laser Desorption Ionisation–Time of Flight Mass Spectrometry and 16S rRNA gene sequence analysis for the species identification of Enterococcus spp. isolated from water
Authors: Taučer-Kapteijn Maja , Medema Gertjan , Hoogenboezem Wim
Published: September 2013

Matrix-Assisted Laser Desorption Ionisation–Time of Flight Mass Spectrometry (MALDI–TOF MS) has increasingly been used for rapid and reliable identification of clinically relevant micro-organisms. To establish the applicability of this technique in (drinking) water quality analysis, the MALDI–TOF MS identification results for Enterococcus spp. isolated from various water environments were compared with those obtained using the commercial Rapid 32 ID Strep system. One hundred and one bacterial isolates were isolated from various types of water and determined as enterococci on the basis of their growth on Slanetz-Bartley agar in typical colonies. The isolates were identified by MALDI–TOF MS and the commercial biochemical test Rapid 32 ID Strep. Isolates yielding in discrepant identifications were genotyped using 16S rRNA gene sequence analysis. For 86 isolates (85%), the results of Rapid ID 32 Strep were identical to those obtained with MALDI–TOF MS. Six isolates were impossible to be classified by means of the Rapid 32 ID Strep test. And for eight out of a total of nine discrepant results (89%), the 16S analyses confirmed the MALDI–TOF MS identification. MALDI–TOF MS produced highly reproducible results. These results indicated that the use of two different culture media had no effect on the identification. In addition, no significant differences (p = 0.32; n = 20) were evident between the scores obtained from a 20-fold measurement of the same isolate. The results of this study showed that MALDI–TOF MS identification (Bruker) is a reliable method for identifying E. faecium, E. faecalis, E. durans, E. hirae and E. casseliflavus isolated from water samples. E. mundtii and E. moraviensis were not included in the Rapid 32 ID Strep database and could therefore not be identified using that test set. However, MALDI–TOF MS and 16S identified all six isolates as members of these species.
Kinvolved: Utilizing Technology to Communicate, Evaluate, and Advocate for Improved Attendance and Family and Community Engagement
Authors: Altman Miriam , Meis Alexandra
Published: September 2013

The American K-12 grade education system is experiencing a truancy crisis. Nationally, 15%, or 7.5 million students, miss an entire month of school annually [1], with that rate frequently doubling or even tripling among students from underserved communities [2]. Research has identified attendance as one of three primary indicators of high school graduation; in the United States today, nearly 35% of students will not earn a high school diploma within 4 years [3]. Ten states (CA, KY, MS, OR, IL, MO, TX, WA, ID, NC) specifically fund schools based on the Average daily Attendance model, through which schools are paid for the number of students in attendance everyday. In San Diego, where schools earn $29 per day for each student recorded “present,” the cost of absenteeism has amounted to $624 million over the last 5 years [4]. A Gates Foundation study found that 71% of recent dropouts believe the most effective way to have kept them and to keep their peers in school is to increase communication with families [5]. These research findings, coupled with the authors' teaching and parent advocacy experiences, have inspired Kinvolved, an organization dedicated to increasing K-12 attendance, particularly among underserved students, by implementing holistic solutions that integrate modern technology and human capital.
Consideration of ICD-9 Code-Derived Disease-Specific Safety Indicators in CKD
Authors: Hartley Iris R. , Ginsberg Jennifer S. , Diamantidis Clarissa J. , Zhan Min , Walker Loreen , Rattinger Gail B. , Fink Jeffrey C.
Published: September 2013

Background and objectives

The Agency for Healthcare and Research Quality patient safety indicators track adverse safety events in hospitalized patients but overlook safety incidents specific to CKD. This study considers candidate CKD-pertinent patient safety indicators and compares them with the Agency for Healthcare and Research Quality patient safety indicators.

Design, setting, participants, & measurements

Using a national Veterans Health Administration database of hospitalized veterans from fiscal year 2005, 247,160 hospitalized veterans with prehospitalization measures of renal function were retrospectively examined for proposed CKD patient safety indicators versus Agency for Healthcare and Research Quality patient safety indicators using International Classification of Diseases, Ninth Revision diagnosis codes. Candidate CKD-pertinent patient safety indicators included in-hospital acute kidney failure; in-hospital congestive heart failure (and related diagnostic codes); electrolyte disturbances; and medication errors, poisoning, and intoxication. Patients with a prehospital estimated GFR<60 ml/min per 1.73 m2 (CKD group) were compared with a non-CKD group. For CKD patient safety indicators, hospitalizations were excluded if the admitting condition was a potential cause of the secondary condition. Regression methods were used to present adjusted rates in study groups of interest.

Results

The CKD patient safety indicators were generally more common than the Agency for Healthcare and Research Quality patient safety indicators in all groups, tended to occur in different patients than those patients who experienced Agency for Healthcare and Research Quality patient safety indicators, and were more common in the CKD group than the non-CKD group, except for hypoglycemia, hypokalemia, and hyponatremia. The adjusted composite CKD patient safety indicators rate (per 1000 patient-hospitalizations) was 398.0 (95% confidence interval, 391.2 to 405.0) for patients in the CKD group and 250.0 (95% confidence interval, 247.4 to 252.7) for patients in the non-CKD group. The prevalence ratio of CKD patient safety indicators to Agency for Healthcare and Research Quality patient safety indicators was 23.4 (95% confidence interval, 21.9 to 25.0).

Conclusion

The candidate CKD patient safety indicators that occur in hospitalized patients are distinct from the Agency for Healthcare and Research Quality patient safety indicators and tend to be more common in CKD than non-CKD patients. These measures have the potential to serve as sentinel tools for identifying patients with CKD who warrant examination for disease-pertinent safety events.
Performance improvement of double-tube gas cooler in CO2 refrigeration system using nanofluids
Authors: Sarkar Jahar
Published: September 2013

The theoretical analyses of the double-tube gas cooler in transcritical
carbon dioxide refrigeration cycle have been performed to study the
performance improvement of gas cooler as well as CO2 cycle using Al2O3, TiO2,
CuO and Cu nanofluids as coolants. Effects of various operating parameters
(nanofluid inlet temperature and mass flow rate, CO2 pressure and particle
volume fraction) are studied as well. Use of nanofluid as coolant in
double-tube gas cooler of CO2 cycle improves the gas cooler effectiveness,
cooling capacity and COP without penalty of pumping power. The CO2 cycle
yields best performance using Al2O3-H2O as a coolant in double-tube gas
cooler followed by TiO2-H2O, CuO-H2O and Cu-H2O. The maximum cooling COP
improvement of transcritical CO2 cycle for Al2O3-H2O is 25.4%, whereas that
for TiO2-H2O is 23.8%, for CuO-H2O is 20.2% and for Cu-H2O is 16.2% for the
given ranges of study. Study shows that the nanofluid may effectively use as
coolant in double-tube gas cooler to improve the performance of transcritical
CO2 refrigeration cycle.
Solar energy contribution to the energy demand for air conditioning system in an office building under Tripoli climate conditions
Authors: Musbah Mohamed , Zivkovic Branislav , Kosi Franc , Abdulgalil Mohamed , Sretenovic Aleksandra
Published: September 2013

The feasibility of solar assisted air conditioning in an office building
under Tripoli weather conditions is investigated in this paper. A
single-effect lithium bromide absorption cycle powered by means of flat-plate
solar collectors was modeled in order to predict the potential of the solar
energy share. The cooling load profile was generated by using an detailed
hourly based program and Typical meteorological year for Tripoli. System
performance and solar energy fraction were calculated by varying two major
parameters (collector?s slope angle and collector area). The maximum solar
fraction of 48% was obtained by means of 1400 m2 of collector surface area.
Analysis of results showed that, besides the collector surface area, the main
factors affecting the solar fraction were the local weather conditions
(intensity of incident solar radiation) and the time of day when the plant
was operated.
Investigation on effect of equivalence ratio and engine speed on homogeneous charge compression ignition combustion using chemistry based CFD code
Authors: Ghafouri Jafar , Shafee Sina , Maghbouli Amin
Published: September 2013

Combustion in a large-bore natural gas fuelled diesel engine operating under
Homogeneous Charge Compression Ignition mode at various operating conditions
is investigated in the present paper. Computational Fluid Dynamics model with
integrated chemistry solver is utilized and methane is used as surrogate of
natural gas fuel. Detailed chemical kinetics mechanism is used for simulation
of methane combustion. The model results are validated using experimental
data by Aceves, et al. (2000), conducted on the single cylinder Volvo TD100
engine operating at Homogeneous Charge Compression Ignition conditions. After
verification of model predictions using in-cylinder pressure histories, the
effect of varying equivalence ratio and engine speed on combustion parameters
of the engine is studied. Results indicate that increasing engine speed
provides shorter time for combustion at the same equivalence ratio such that
at higher engine speeds, with constant equivalence ratio, combustion
misfires. At lower engine speed, ignition delay is shortened and combustion
advances. It was observed that increasing the equivalence ratio retards the
combustion due to compressive heating effect in one of the test cases at
lower initial pressure. Peak pressure magnitude is increased at higher
equivalence ratios due to higher energy input.
Agglomeration problems during cardoon fluidized bed gasification
Authors: Christodouloua Christos , Koytsoumpaa Efthymia-Ioanna , Panopoulos Kyriakos , Karellas Sotiris , Kakarasa Emmanouil
Published: September 2013

Cynara cardunculus, commonly known as cardoon is a potential energy crop
native to the Mediterranean region with high production yields reported. The
aim of this work is to present an overview on the contradicting agronomic
data available for cardoon and its potential exploitation in industrial
thermochemical (i.e. combustion and gasification) applications. Moreover,
experimental work on cardoon gasification is presented, focusing on the
agglomeration problems it causes when using it in fluidized bed gasifiers.
Cardoon cultivated in Greece was gasified in a 100 kW thermal atmospheric
circulating fluidized bed gasifier (ACFBG). Due to high ash content (rich in
potassium) defluidization was observed at low temperatures (780?C) during the
first 30 minutes after the fuel feeding begun. The agglomerates are
investigated with SEM/EDS in an effort to determine the gluing mechanism. The
particular cardoon was rich in calcium, and this was apparent in the rich in
silicates resolidified melt.
Marketing in the Tax Administration in Albania
Authors: Manoku Elfrida , Kalia Mimoza
Published: September 2013

After the late 1970s the marketing discipline has known a considerable expansion and application not only in private sector but also in public or non-profit sector. Currently the debate is focused on how to better integrate the marketing concept and marketing function into the activities of government organizations as means of increasing the effectiveness of the delivery of public policy and citizens satisfaction. Public marketing is a new concept for the Albanian reality and very slowly is entering into the management approach. The aim of this paper is to evaluate how much is known and accepted the concept of marketing in the Albanian public sector and if this level of acceptance or rejection is reflected in the use of marketing strategies and tactics as instruments of public management.

After a critical review of the literature about the last trends and research in this issue, qualitative methods are used through a case study in General Directorate of Taxation in Albania. In depth semi-structured interviews with several senior directors and officers were conducted to see the level of perceptions and practices thorough the major departments of this Institution. From the analysis of data gathered resulted that marketing is mostly equated with public relations function and was considered unnecessary and as a significant consumer of public funds. A number of recommendations are given on how to build an efficient marketing model for the General Directorate of Taxation in order to help increasing efficiency and quality of service to citizens.
Hedge Funds Development and their Role in Economic Crises
Authors: Palaskas Theodosios , Stoforos Chrysostomos , Drakatos Costantinos
Published: September 2013

The rapid development of hedge funds and their emanating critical role in the financial markets and the financial system globally, combined with the increased frequency of economic crises during the last 25 years, brought them to the centre of discussions concerning the following issue: «To what extent the operation of hedge funds can affect the birth, peak and even geographic expansion of economic crises?». In this context, the present paper aims to contribute to the limited and sporadic discussion of whether the hedge funds could be held responsible for economic crises. To this extend the growth and the impact of hedge funds on financial crises is analysed and evaluated using the HFR database -in their birth, aggravation or even geographic expansion- both from a historical perspective and in relation to the 2007-today crisis. Based on the evidence presented in this paper, hedge funds cannot be blamed for the birth of the crises of the last 25 years. Comparing the data across the different crises, it becomes obvious that, with the exception of the 2007 subprime crisis, where almost all hedge fund strategies suffered considerable losses, in all other crises studied in the present paper, the hedge fund strategies with a negative return were the ones that had an exposure to the specific sector and/or region that was in the centre of the crisis i.e. Emerging market strategy presented substantial negative monthly performance over the Asian crisis, Convertible arbitrage strategy was affected by the dot-com crisis, etc.
Socially Responsible Mutual Funds – A Profitable Way of Investing
Authors: Slapikaite Indre , Tamosiuniene Rima
Published: September 2013

In the presented paper there is analyzed the idea, essence and strategies of socially reponsible investing, there is also made a review of socially responsible mutual fund market worldwide and in the Baltics, and made a research on the relation between financial and social performance of mutual funds. Finally, there are presented results of a comparative analysis of S&P 500 TR and Index Morningstar Moderate Target Risk to their benchmarks. The presented results show the trends of socially responsible market and the effectiveness of socially responsible mutual funds comparing to their benchmarks. The specifics of socially responsible mutual market in the Baltics and research of the link between financial and social performances of mutual funds may lead to the further scientific researches.
Geothermal heat flux anomaly due to a 3D prismoid situated in the second layer of a three-layered Earth
Authors: Hvoždara Milan , Majcin Dušan
Published: September 2013

We present mathematical modelling of the stationary geothermal field for the three-layered earth which includes a three-dimensional perturbing body below the first layer (over the halfspace substratum). The unperturbed temperature field corresponds to the uniform vertical heat flux. The perturbing body is in the form of 3D prismoid with sloping side faces, while its upper and lower face are rectangles at the planes z = z1, z2. The theoretical formulae are based on the generalized theory of the double-layer potential and boundary integral equation (BIE). Special attention is paid to the quadrilateral prismoids bounded by planar skew faces. The numerical calculations were performed for the 3D prismoids (blocks), the thermal conductivity of which was greater than that in the ambient second layer, while the upper face of the prismoid may be in contact with the upper layer and the lower face may touch the bottom halfspace. Numerous graphs are shown for the disturbance of the temperature and heat flow distribution on the surface of the Earth or inside all three layers.
The first tidal analysis based on the CG-5 Autograv gravity measurements at Modra station
Authors: Mikolaj Michal , Hábel Branislav
Published: September 2013

We present the tidal parameters estimated for the absolute gravity site in Modra (Slovakia). This is the first tidal analysis based on gravity measurements for this location. Relative gravity variations observed by Scintrex CG-5 Autograv gravimeter were used for the tidal analysis. We observed large and non-linear instrumental drift which cannot be effectively eliminated by polynomial approximation. Drift was eliminated by a filtering. New set of tidal parameters was estimated and analyzed with the focus on diurnal and semi-diurnal tidal waves. Time and frequency domain comparison between new parameters and those obtained from the superconducting gravimeter located in Vienna was performed. A maximum amplitude factor difference of 0.2% was found between main tidal waves corrected for ocean tides and non-hydrostatic body tide model. New estimated tidal parameters can serve for the correction of local relative gravity measurements
Habitat selection by two species of dung beetle, Anoplotrupes stercorosus (Scriba) and Trypocopris vernalis (L.) (Coleoptera: Geotrupidae), changes with stand age in a fresh pine forest
Authors: Marczak Dawid
Published: September 2013

In Poland, Anoplotrupes stercorosus (Scriba) and Trypocopris vernalis (L.), are very common throughout the whole country and belong to the most numerous representatives of the Geotrupidae family. Research on the habitat selectivity of Anoplotrupes stercorosus (Scriba) and Trypocopris vernalis (L.) was conducted in the years 2004-2006 in the Wipsowo Forest Inspectorate (Regional Forest Department in Olsztyn). The dung beetles were collected using Barber traps installed in a clearcut comprising, 2, 3, 5, 8, and 16 year old thickets and tree-stands aged 30, 45, 60, 80, 100 and 135 years. According to phytosociology these tree-stands are a plant community of fresh continental pine forest (Peucedano-Pinetum), while typologically all sites are within the fresh coniferous forest. During the course of this research 29197 individual dung beetles were captured, including 23137 individuals of A. stercorosus and 6060 individuals of T. vernalis. Both species were caught at each research site. At nearly all sites A. stercorosus dominated. Only within the clearcut area were the number of T. vernalis was higher than at other sites. Very many individuals of T. vernalis were present in the clearcut area but their numbers decreased gradually with increasing tree-stand age. An opposite situation was noted for A. stercorosus. There was an interesting statistically-significant decrease in the abundance of both species in the middle-aged tree-stands - 30, 45 and 60-year-old. Analysing the seasonal dynamics revealed one peak in the population of T. vernalis in July, whereas there were two peaks in the population of A. stercorosus: a small peak in July and a much larger peak in September. There was a significant negative correlation between the numbers of T. vernalis and tree-stand age (p<0.05, r =-0.57), and a significant positive correlation between the A. stercorosus population size and tree-stand age (p<0.05, r = 0.48)
Globe flower Trollius europaeus L. in forest and forest edge communities of the northern part of Południowopodlaska Lowland
Authors: Ciosek Marek Tadeusz , Piórek Katarzyna
Published: September 2013

The distribution of Trollius europaeus in the northern part of the Południowopodlaska Lowland was described and a phytosociological study made of the localities where it was present between 2010 and 2012. The condition of all sites where T. europaeus was historically present was also verified. These field studies reveal that the number of sites of occurrence and the abundance of T. europaeus populations have rapidly diminished over recent years. Only 15 populations of the species in the vicinity of 7 sites were confirmed. Trollius europaeus is usually considered a species characteristic of moist meadows of ordo Molinietalia and in the plant community type, Polygono bistortae-Trollietum. In the northern part of the Południowopodlaska Lowland, no meadow sites containing Trollius europaeus still remain according to our survey. All the confirmed stands are situated in deciduous forests of class Querco-Fagetea (Tilio-Carpinetum and Potentillo albae-Quercetum) and moist forest edge communities of ordo Glechometalia. The disappearance of all meadow populations is mainly considered a result of intensification of the agricultural use of these habitats. We suggest that the category of threat to Trollius europaeus is increased on the regional list from VU to EN, and consolidated with further monitoring and active protection of stands where it is present
Effect of resin-tapping on the radial increment of Scots pine (Pinus sylvestris L.) – case study of a stand from Lidzbark Forest District
Authors: Magnuszewski Michał , Tomusiak Robert
Published: September 2013

The study makes an attempt to evaluate the effect of resin-tapping on the radial increment of Scots pine (Pinus sylvestris L.). Increment cores were taken from two groups of trees: resin-tapped trees and normal trees growing in a 148-year-old pine stand in the Lidzbark Forest District. The cores were taken with the Pressler increment borer from two heights on the tree trunk: 1,30 m and 3,30 m. Using dendrochronological methods, real chronologies were built for each of the four analysed groups of cores. The value and variability of increments for each group were investigated in 20 and 40 year time periods, before and after the start of resin-tapping. In next step, the chronologies were compared and their coefficients of conformity were calculated. As a result, we can state that the radial increments were larger are at 1,3 m height after resin-tapping than before resin-tapping. There was also significant effect of resin-tapping on radial growth at the height 3,3 m, above the resin-tapping face.
Deposition of a polymeric porous superhydrophobic thin layer on the surface of poly(vinylidenefluoride) hollow fiber membrane
Authors: Ahmad A.L. , Mohammed H.N. , Ooi B.S. , Leo C.P.
Published: September 2013

Porous superhydrophobic layer of low-density polyethylene (LDPE) was created by a simple approach on the Poly(vinylidenefluoride) (PVDF) hollow fiber membranes. Acetone and ethanol mixtures with different volume ratios were used as the non-solvent on the coating surface. A 5:1 (v/v) acetone/ethanol ratio provided a porous surface with a 152° ± 3.2 water contact angle. The high contact angle could reduce membrane wettability for better carbon dioxide capture when the membrane was used as gas-liquid contactor in absorption processes. To assess the effect of the created superhydrophobic layer, the pristine and modified membranes were tested in a CO2 absorption system for ten days. The results revealed that the absorption flux in the modified membrane was higher than that of pristine membrane.
The unconventional single stage hydrolysis of potato starch
Authors: Słomińska Lucyna , Zielonka Roman , Jarosławski Leszek
Published: September 2013

Enzymatic depolymerisation of starch to glucose or maltose is carried out by starch- degrading amylases during a two-stage hydrolysis: liquefaction using bacterial α-amylase followed by saccharification with glucogenic (fungal amylase) or maltogenic (fungal or bacterial) amylases. As a rule, these enzymes are applied separately, following the recommendations concerning their action provided by the enzyme manufacturers. The study presents our attempts to determine the reaction conditions for a simultaneous action of liquefying and saccharifying enzymes on pre-treated potato starch. Hydrolysis was run by Liquozyme Supra, Maltogenase 4000L and San Super 360L enzymes (Novozymes) at different temperatures. During the single-stage method of starch hydrolysate production the most desirable results was obtained for the maltose hydrolysate at 80°C (51.6 DE) and for the glucose hydrolysate at 60°C (96 DE). The analyses indicate that the application of a single-stage hydrolysis of starch to maltose or glucose makes it possible to obtain a degree of starch saccharification comparable with that obtained in the traditional two-stage hydrolysis.
Structural disordering in Sn-Pb(Bi) eutectic melts induced by heating
Authors: Mudry S. , Shtablavyi I. , Shevernoga I.
Published: September 2013

The structure of liquid Sn0.739Pb0.261 and Sn0.57Bi0.43 eutectic alloys was studied by means of X-ray diffraction at several temperatures. Structure factors, pair correlation functions and the main structural parameters obtained on their basis were analyzed. We show that the structure of the Sn0.739Pb0.261 and Sn0.57Bi0.43 eutectic alloys is inhomogeneous and consists of different types of clusters. Upon heating the cluster structure undergoes topological and chemical disordering showing a significant dependence of structural parameters on temperature near the melting point
Magnetic recykling of complex catalysts immobilized on thiol-functionalized polymer supports
Authors: Bączek Natalia , Strzelec Krzysztof , Wąsikowska Karolina
Published: September 2013

In this work, the application of the thiol-functionalized epoxy resin encapsulated on magnetic core as supports for palladium catalysts is reported. The study focuses on obtaining of heterogeneous catalysts which can be separated by magnetic field. Palladium complex catalyst [PdCl2(PhCN)2] has been heterogenized by anchoring to these supports via ligand exchange reaction. The characterization of polymeric supports and heterogenized palladium catalysts has involved research methods like time-of-flight secondary ion mass spectrometry (TOF-SIMS), scanning electron microscopy (SEM) and nitrogen BET surface area measurements. The activity and stability during long-term use of the investigated catalytic systems were tested in a Heck and hydrogenation reaction. The influence of the type of thiols used as epoxy hardeners and the morphology of the supports on the catalytic properties of epoxy-supported palladium catalysts was discussed.