bluuebunny/crossref_metadata_2025 huggingface dataset:
Paradigm Shift in Egypt's Western Desert: Premium Grade Steel-Body Bits Displacing Matrix Designs in Key Applications
Authors: Kamel Osama , Mansour Mahmoud , Ibrahim Abdelshafy , Reyad Mahmoud , Hanafy Omar , Sherif Mohamed , Aguib Karim , El Sheikh Omar , Bits Smith
Published: March 2015

Recent manufacturing and hardfacing advances have produced a steel-body PDC bit (SB-PDC) capable of efficiently drilling interbedded formations at significant depth. These technological advances have increased the bit's resistance to abrasion/erosion and enabled a new style steel-body PDC bit to drill formations in Egypt's western desert previously drilled by matrix PDC bits. Field tests have confirmed the steel-body PDC bit can outperform matrix PDCs in a wide-range of interbedded applications that contain a heterogeneous mixture of shale, sand/siltstone, and limestone. The approach combines optimized cutting structure design and premium PDC cutters that enable the steel-body PDC bit to drill the abrasive sand/siltstone component. The bit can also efficiently drill shale and soft limestone due to its hydraulic efficiency which was a factor limiting performance improvement in previous designs. The bit solution employs: ➣Cutting structure optimized using FEA-based modeling system➣Premium grade PDC cutters➣Next generation of abrasion/erosion resistant hardfacing material➣Hydraulically efficient bullet-shaped body type

The new SB-PDC technology was deployed in a sequence of tests in different applications and fields in Egypt's western desert. The trials were run in different lithologies at different depths. Direct comparisons to relevant matrix PDC technology and other available steel-body bits clearly demonstrates the new-style steel-body PDC bit's value by setting new benchmarks and reducing cost/ft.
Equalizing Well Pressure Drop with Swirl Chambers
Authors: Noui-Mehidi Mohamed N.
Published: March 2015

The present paper is concerned with a numerical study of swirl flows applied as a pressure equalization means in an inflow control devices (ICD) setup. The system discussed includes an isolated mechanical flow path that is designed as a conical channel through which the produced fluids are injected with a tangential inlet. The system forms a swirl chamber that generates a swirling flow that decays along the flow path. The active swirl part arrangement could be mounted in serial sections along the flow path to maintain the swirl properties of the flow over the desired distance. The swirl motion generates a pressure drop that is related to the length, gap width, and tangential inlet size of the swirl element. The present work presents a numerical investigation of this system by studying the primary flow variables using a finite difference method. The numerical results revealed the flow nature and the resulting pressure drops with regard to the flow system variables.
A Paradigm Change In Water Flood Strategy Using Horizontal Injectors In The Sabriyah Field, North Kuwait
Authors: Jamal Mariam Abdul-Raheem , Chetri Hom , Al-Towaitan Tasneem , Badusha Sayed Ibrahim , AL-Zaabi Hamad
Published: March 2015

As one of KOC's main Oil Production field's North Kuwait is developing projects and support activities to increase Oil production to one million bbl. /day by 2017-2018. A critical and vital part art of this Oil Production strategy are the major water injection projects. Based on last 10 years of water flood experiences, the water flooding strategy was modified to add horizontal injectors to help accelerate pressure maintenance to the critical pressure sink areas, in particular, and pressure support to the giant NK Sabiriyah Mauddud reservoir, in overall.

An example of this being Well SA-M HST1, a existing vertical injector, was chosen to be horizontally side tracked, the primary purpose being to improve and enhance the reservoir pressure in the Northern part of the field which historically in the past has exihibited decline in pressure due to a increased offtake. Preliminary results are positive and show a reduction in the reservoir pressure decline rate, Stabilization in ESP intake pressures at offtake wells & Reduction in the frequency of ESP trips.

To understand and analyse completely the response behavior, a comprehensive monitoring of SA – M HST1 injector has been initiated, covering several tarcking items such as Well head pressure readings, Flow line pressure readings, Gathering center water cuts tests, Water cut samples, Static bottom hole pressure for the closed wells in the pattern, Production logging for the injector and producers, Flowing bottom hole pressures and time lapsed portable tests. Monitoring has been planned for a period of six months to understand clearly the vertical pressure connectivity between the productive layers within the reservoir, and also more importantly the impact on the production behavior of the surrounding wells. The paper then closes and shares with the reader the lesson learnt and the next steps.
Offshore Pipeline Precommissioning Operations Using Coil Tubing Units
Authors: Mikhailov M.
Published: March 2015

Coil Tubing has been used in many oilfield applications worldwide both offshore and onshore, upstream and recently downstream.

Apart from upstream coil tubing applications such as workovers, well interventions, paraffin/scale removal, jetting, acidizing and coil fracturing, it is employed more and more actively for pipeline precommissioning operations subsea, especially dewatering. With a slight modification (there is no need for a BlowOut Prevention (BOP) System in this case) the coil tubing unit is positioned on a vessel's deck and connected to a high-pressure compressor spread injecting pressurized air down the coil tubing string to the hot stab connection of the pipeline to be dewatered. Pressure drops across the tubing string and other connections and flow patterns can be simulated using Baker Hughes' proprietary software CIRCA™. For deep water offshore applications high pressure boosters are often employed.
In-Line Water Separation: A New Promising Concept for Water Debottlenecking Close to the Wellhead
Authors: Abbad Mustapha , Dyer Steve , Ligneul Patrice , Badri Mohammed
Published: March 2015

This work presents a new technique which allows in-line water/oil separation directly from the pipeline and close to the wellhead. It enables an increase of the oil/water ratio in the pipeline and decreases the cost of water transportation and handling. The separation process relies on the detection of the water front level in an oil/water stratified flow in an inclined pipe. The main line has a T-junction connected to a control valve from which the water is extracted. The position of the water front is detected by a set of resistivity/capacitance probes and a proprietary feedback control algorithm which allows water extraction rate. The combination of the pipe inclination and the control system ensures that mostly oil is flowing in the main pipe and mostly water is flowing through the extraction T-junction. The concept has been studied theoretically, numerically and experimentally. A laboratory scale flow loop model was built and tested to validate this technique in a controlled environment. Then, it was upscaled into a field size prototype that captured the various specifications required for an efficient water/oil separation. The cleanness of the separated water is measured in the lab experiment as well as in the full-scale prototype using a fluorescence technique. The obtained results show that the extracted water rate might exceed 70% of the water initially measured at the inlet of the separator, and it contains less than 500 ppm of oil. The system is currently under consideration for field trial.
First Successfull Implementation Of High Temperature Video Camera to Identify Downhole Obstructions in Gas Wells: A Saudi Case
Authors: Mukhliss Amroo E. , Driweesh Saad M. , Sagr Abdulaziz M. , Bolarinwa Simeon , Wiltosz Mark
Published: March 2015

Video cameras have been used in the oil industry with high success rate reported by several operating companies around the world. However, High downhole temperatures especially in gas wells have always posed a limitation to the full utilization of the camera as a diagnostic tool. Previous trials with the camera were prematurely aborted as internally it tends to heat up quickly allowing no time to carry out the full diagnosis of the restriction. However since the camera has gone through extensive modifications and has been equipped with the necessary capabilities to withstand high downhole temperatures.

Picture resolution, re-fresh rate, LED intensity and tool rotation can be controlled at surface by the operator. Well deviation, high side and internal tool temperature are among the parameters displayed at E-line Cabinet on surface.

This paper documents a successful operational experience of the first HT run in Saudi Arabia using this type of downhole camera. E-Line High Temp camera was deployed in gas well in attempt to determine the cause of an unpassable obstruction. Several measures to diagnose the nature of this obstruction were attempted using series of gauge cutter runs but with no success. The High Temp camera was mobilized in an attempt to finally discover the severity and extent of this obstruction.

The operation using the downhole camera was carried out successfully achieving the desired objective of the intervention. The interpretation of the images indicated that the well had some kind of mineral build-up which looks to be solid in appearance indicating scale or cement materials.
Overcoming Environmental and Technical Challenges for Well Integrity—A Global Perspective
Authors: Johnson Carl R. , Shindgikar Nikhil Dilip , Beurel Muriel Martin
Published: March 2015

Globally, there is increasing focus on hydrocarbon recovery in regions that are new to environmental legislation and regulation; very often this is an offshore environment where well integrity has broad effects. Providing environmentally compliant fluids is standard, and thus expertise in regulations and “green” chemistry is rapidly being pulled from established regions such as the North Sea. The expectation that both regulations and the chemistry can be slotted into the new region's operations is difficult to achieve, as there is no single set or universal set of regulations; so no ‘one-size-fits-all’ solution.

This paper addresses numerous distinct challenges for cementing-related fluids and how the changing regulatory stage across different regions can be optimally managed. Indeed, as these regions can be “frontier” or remote in nature, emphasis on cost control from operators is high to minimize the well construction cost. This may not align with environmental compliance expectations. Particular examples, from West Africa, will be presented to highlight challenges toward conformity with the aim of discussing the pitfalls and potential solutions available.

Environmental regulations and practices are continually evolving, and come under increasing scrutiny at the well planning stage, with heavy emphasis on well integrity and cementing quality. The most legislated region of offshore E&P is the North Sea, and, naturally, governing bodies and operators are adopting North Sea regulatory models elsewhere. Through case histories covering North Sea, French Guiana, West Africa, the Arctic, Canada, and Australia, a systematic review of the numerous approaches governing the application of cementing fluids for well integrity will be deliberated. An innovative “green” chemistry solution for high-pressure/high-temperature (HP/HT) operations, developed to tackle compliance with Norwegian North Sea regulations, will act as key example of steps taken to safeguard global environmentally sensitive regions and ensure long-term well integrity.
Permian Frac Systems Using Produced Water
Authors: Kakadjian Sarkis , Thompson Joseph , Torres Robert , Pontifes Antonio , Rodriguez Amanda , Hamlat Yahia Ait
Published: March 2015

In areas where fresh water costs and produced water disposal costs become problematic, operators as well as service companies have shown the desire to use produced and flow back water in field operations to enhance the overall completions economics. This paper shows the experience of new Stabilized Crosslinked Fracturing fluid systems pumped in the Permian Basin (West Texas, United States) using borated produced water with levels of Total Dissolved Solids (TDS) exceeding 30,000 mg/L.

The new Frac fluid systems are developed for temperature ranges between 120-220 °F and designed to delay the crosslinking time when needed, utilizing the boron already present in the water. In addition to the technical success, the back end costs are significantly reduced by transporting produced and/or flowback water to locations for re-use rather than disposing them into well(s) located miles away. This unique Frac fluid systems approach, which conserves fresh water aquifers and recycles produced and flowback water, has broken the code for recycled water and reduced disposal costs significantly. The operators and the service company have pumped numerous stages using only sock filtration to decrease the level of suspended solids in the waste water. This paper reports laboratory testing and case history data.
Experimental Investigation of Three-Phase Immiscible Floods during Gas Gravity Drainage in Naturally Fractured Reservoirs
Authors: Netaifi A. S. , Cinar Y.
Published: March 2015

This paper presents results of a systematic laboratory study to investigate how three-phase immiscible flow can affect gravity-drainage gas injection in naturally fractured reservoirs. In the experiments, quasi two-dimensional glass-bead packs represented matrix and grooved glass strips the fractures. A three-phase hydrocarbon-water-alcohol system mimicked immiscible fluids. Conductive and isolated fractures were examined for two different flow rates. Continuous gas injection, water-alternate-gas and simultaneous water-alternate-gas injection schemes were run. A scaling analysis was conducted to quantify effects of viscous, capillary and gravity forces on the displacement performance for each experiment.

Experimental results show that displacements were controlled mainly by capillary forces. The comparison between injection schemes shows that the continuous gas injection scheme yields highest ultimate recovery. An injection efficiency factor is introduced to assess the feasibility of injection process, which demonstrates that the optimum injection occurs through the water-alternate-gas injection. This is because of the minimum gas consumption, the gas phase which improves the microscopic displacement efficiency in gravity-stabilised floods and the water phase that supports the macroscopic sweep efficiency by preventing the gas phase from fingering. It is found that the oil recovery and injection efficiency in the experiment with the isolated fracture are higher than in the experiment with the conductive fracture model.
Development of priority setting process for the small stream restoration projects using multi criteria decision analysis
Authors: Seo Jung Pyo , Cho Woncheol , Cheong Tae Sung
Published: March 2015

This study performed a flood risk assessment using one of the multi criteria decision-making methods to identify the small stream basins with high risk of flooding and to determine the optimal small stream restoration measures by priority ranking for flood risk. The 12 representative factors for the flood risk assessment were carefully selected and constructed for the three main aspects, such as pressure factors, state factors and response factors including the government capacities under the pressure-state-response classification system for identifying the 212 small stream watersheds. The entropy weight coefficient method helps to reduce subjective judgments as well as calculate effective weighting coefficients. To evaluate the practical applications of the proposed method, the results from the preference ranking organization method for enrichment evaluation (PROMETHEE) with six preference functions are compared with the official priority ranking of flood risk assessment for the Small Stream Watershed Restoration Projects which is determined by the weighted method. Also, guidelines for the community-based restoration projects such as prevention or preparedness, sustainable development and resilient recovering have been suggested based on the three predicted priority ranking groups. It is expected that the flood risk assessment ranking ensured by full verification can help to establish optimal regional restoration plans against flooding disasters with respect to causes and characteristics of past flash flood.
Spatial diversity of chlorine residual in a drinking water distribution system: application of an integrated fuzzy logic technique
Authors: Termini Donatella , Viviani Gaspare
Published: March 2015

A reduction in the concentration of chlorine, which is used as a chemical disinfectant for water in drinking water distribution systems, can be considered to be an index of the progressive deterioration of water quality. In this work, attention is given to the spatial distribution of the residual chlorine in drinking water distribution systems. The criterion for grouping the water-quality parameters normally used is highly subjective and often based on data that are not correctly identified. In this paper, a cluster analysis based on fuzzy logic is applied. The advantage of the proposed procedure is that it allows a user to identify (in an automatic way and without any specific assumption) the zonation of the network and easily calibrate the unknown parameters. An analysis of the correlation between the sampling sites for the residual chlorine has been used to assess the applicability of the procedure.
Effective pathogen removal by low temperature thermal pre-treatment and anaerobic digestion for Class A biosolids production from sewage sludge
Authors: De los Cobos-Vasconcelos Daniel , Villalba-Pastrana María Elena , Noyola Adalberto
Published: March 2015

Production of Class A biosolids depends mainly on the effective control of thermotolerant coliforms and Salmonella spp. Thermal pre-treatment followed by anaerobic mesophilic digestion may be a simpler and more sustainable option to accomplish this compared with other process arrangements. In this work, removal and inactivation of thermotolerant coliforms and Salmonella spp. in waste municipal sludge were studied at three thermal pre-treatment conditions in batch tests (60, 70 and 80 °C). Effective removal was obtained with 70 °C and one-hour pre-treatment, but reactivation of both pathogens was noticed in the following step using an anaerobic mesophilic digester. Predictive microbial decay models (Weibull and sigmoidal-empirical) were used for fitting the experimental data. The sigmoidal-empirical model showed better results at the final counts, suggesting thermal adaptation of some microbial subpopulations. In order to overcome this unexpected result, the influence of the cooling phase was also studied applying three different conditions. For effective treatment, a fast cooling step (in this case, an ice-bath with sodium chloride) should follow thermal pre-treatment (70 °C and 60 min). At these conditions, no reactivation or re-growth of both pathogen indicators were seen during the following 48 h under anaerobic mesophilic digestion.
Blue Diversion: a new approach to sanitation in informal settlements
Authors: Larsen Tove A. , Gebauer Heiko , Gründl Harald , Künzle Rahel , Lüthi Christoph , Messmer Ulrike , Morgenroth Eberhard , Niwagaba Charles B. , Ranner Bernhard
Published: March 2015

The sanitation concept ‘Blue Diversion’ (www.bluediversiontoilet.com) was developed as a possible answer to the sanitation crisis in urban slums. It is based on two main elements: (1) diversion of urine, feces, and water at the source as the basis for efficient resource recovery, and (2) linking different scales (family toilets and semi-centralized resource recovery). Our objective was to develop an attractive ‘grid-free’ (i.e. functioning without piped water, sewer, and electrical grid) dry urine-diverting toilet, which provides water (through recycling on-site) for flushing, personal hygiene (anal cleansing and menstrual hygiene), and hand washing. This service, including the entire sanitation value chain, should eventually be made available as a profitable business with total user fees of 5 ¢/p/d. The results presented in this paper are (1) a toilet design model, (2) the development of a new type of membrane bioreactor for treating flush and wash water, (3) main results of a geographic information system-based stochastic service model to link the family-scale toilet to a community-scale Resource Recovery Plant, and (4) a business model that yields maximum profit for the local community. We conclude that the approach is feasible, but challenging from a technical as well as an organizational point of view.
A critical evaluation of Rwanda's potential to achieve the millennium development goals for clean water and sanitation
Authors: Abbott Pamela , Tsinda Aimé , Sapsford Roger , Rwirahira John
Published: March 2015

In the world-wide Millennium Development Goals initiative, Rwanda promised to halve by 2015 the number of people who lacked access to safe water and improved sanitation in 1990. Progress has been made in access to water, but the target figure will probably not be met. Targets for improved sanitation will be met on the original definition of ‘improved’, though probably not if shared provision is excluded. However, beyond the usual rural/urban divide, the article highlights how the numerical target conceals a serious problem in the capital city, where ‘informal settlements’ have grossly inadequate provision. We argue that the problems are not soluble at the individual level; a whole and unbreakable chain of provision is needed. Centralised provision is also not very feasible in Rwanda, so Government and/or development partners will probably have to work at the level of communities to set up sanitation chains and train communities in servicing them. Solving the problem is essential if the urban poor are to be offered a decent life and to solve the public health problem of contaminated water.
Drinking water infrastructure in the Ashanti Region of Ghana: developing a model for sustainable interventions by non-governmental organizations
Authors: Alexander D. , Wilson N. , Gieseker R. , Bartlett E. , Rosseau N. A. , Amuzu E. X. , Ansong D. , Olopade O. I. , Olopade C. O.
Published: March 2015

Access to clean water plays a critical role in advancing health in low- and middle-income countries. Over the past decade, Ghana has met United Nations targets for expanding access to clean water. Non-governmental organizations (NGOs) have taken part in this achievement; however, they have done so with varying success. In 2013, researchers from the University of Chicago, accompanied by local partners, visited seven villages in the Ashanti Region in which a Ghanaian NGO had installed boreholes for drinking water access. Household and leader questionnaires were administered to examine the impact of the project on each community. Four additional villages, which utilize surface water, were visited to establish baseline health and sanitation characteristics. Water samples were collected from primary drinking water sources and tested for coliforms. Two out of seven NGO wells were non-functional and over 35% of respondents cited broken pipes as common problems. Nonetheless, over 60% of respondents reported that a borehole had reduced their water collection time by a median of 30 minutes daily. Coliform counts were lower in samples taken from boreholes relative to samples taken from communities using surface water. Finally, we found redundant water services in many communities and no formalized approach to borehole maintenance.
Faecal sludge drying beds: increasing drying rates for fuel resource recovery in Sub-Saharan Africa
Authors: Seck Alsane , Gold Moritz , Niang Seydou , Mbéguéré Mbaye , Diop Cheikh , Strande Linda
Published: March 2015

In urban Sub-Saharan Africa, the collection and transport of faecal sludge (FS) typically ends up with FS directly dumped into the urban environment, as safe treatment and disposal options are too expensive or non-existent. Resource recovery from FS treatment, such as dried FS as an industrial fuel, could provide a financial incentive to increase access to FS management services. In Dakar, Senegal, enhanced drying to reduce the footprint of drying beds for fuel production was evaluated. Greenhouses did not increase drying rates over uncovered beds, however, daily mixing of FS on the surface of the beds resulted in a 6 day reduction to achieve 90% total solids (TS). FS was dried to 90% TS in 2 weeks for loading rates of 100 kg TS/m2*year, and 3 weeks for 150 kg TS/m2*year. The results indicate that with simple but innovative adaptations, footprints of treatment plants could be reduced and/or treatment capacities increased by 20%. FS can be adequately dried in Dakar to produce fuel, meaning 8.25 tons of dried FS could currently be produced daily, contributing 31,403 GJ/year fuel to industries. In addition, this financial incentive could reduce FS that is currently discharged untreated to the environment, and provide an additional 116,705 GJ/year.
Particle counter as a tool to control pre-hydrolyzed coagulant dosing and rapid filtration efficiency in a conventional treatment system
Authors: Gumińska Jolanta , Kłos Marcin
Published: March 2015

Filtration efficiency in a conventional water treatment system was analyzed in the context of pre-hydrolyzed coagulant overdosing. Two commercial coagulants of different aluminum speciation were tested. A study was carried out at a water treatment plant supplied with raw water of variable quality. The lack of stability of water quality caused many problems with maintaining the optimal coagulant dose. The achieved results show that the type of coagulant had a very strong influence on the effectiveness of filtration resulting from the application of an improper coagulant dose. The overdosing of high basicity coagulant (PAC85) caused a significant increase of fine particles in the outflow from the sedimentation tanks, which could not be retained in the filter bed due to high surface charge and the small size of hydrolysis products. When using a coagulant of lower basicity (PAC70), it was much easier to control the dose of coagulant and to adjust it to the changing water quality.
Evidence for an Association Between Tako-Tsubo Cardiomyopathy and Bronchial Asthma: Retrospective Analysis in a Primary Care Hospital
Authors: Blotzheim Leonardo Glutz von , Christen Stefan , Wieser Stephan , Ulrich Silvia , Huber Lars C
Published: March 2015

Objective:

We investigated the prevalence of bronchial asthma in patients with Tako-Tsubo Syndrome (TTS).

Design:

This retrospective case-series study was conducted in a primary care hospital in Zurich, Switzerland. Data of all patients with newly diagnosed TTS (2002 - 2012) were assessed electronically by the use of ICD-10. Asthma prevalence was compared to published epidemiologic data.

Setting:

Bronchial asthma is characterized by airway inflammation and, during attack, release of endogenous catecholamines. Sympathomimetic drugs are the mainstay of treatment for asthma patients. Likewise, catecholamine mediated diffuse microvascular myocardial dysfunction seems to be of critical importance for the development of TTS.

Results:

20 cases of TTS were identified. 90% were female, showed a median age of 70±13y [25y - 90y], an apical and/or midventricular ballooning pattern with preserved basal function and a median initial LVEF of 34±9% [25% - 55%]. 65% of patients underwent coronary angiography to rule out significant coronary artery disease. Hypertension was present in 45% of patients, 35% were smokers, none was suffering from diabetes. Prevalence of asthma in patients with TTS was significantly higher compared to the normal population (25% vs. 7%, p=0.012). In 30% of the TTS patients an iatrogenic cause for development of TTS was identified.

Conclusion:

Prevalence of asthma was significantly higher in patients with TTS compared to epidemiologic data from an age-matched population. Phenotypes of patients developing obstructive ventilatory disease and TTS might share common pathogenic mechanisms beyond the use of bronchodilatators. In addition, we identified other iatrogenic etiologies in patients with TTS.
Contribution of maternal obesity and weight gain in pregnancy to the occurrence of gestational diabetes
Authors: Teodorescu Cristina , Dobjanschi Carmen , Isopescu Florin , Rusu Emilia , Edu Antoine , Radulian Gabriela
Published: March 2015

An increase in prevalence of gestational diabetes mellitus (GDM) was observed
using new diagnostic criteria. We evaluated the prevalence of GDM in a
population of pregnant women (109 women with gestational age of 24-28 weeks)
and risk factors for GDM, such as maternal obesity and weight gain. The
evaluation of each patient included an oral glucose tolerance test (OGTT)
using the new diagnostic criteria of the International Association of
Diabetes and Pregnancy Study Groups (IADPSG) for GDM, 2D ultrasounds and the
registration of risk factors. The prevalence of GDM in the age group ?30
years was 11.9%, which is comparable to the results of other studies. The
relative risk (RR) for GDM was 1.738 (95% CI 0.630-4.795) in women over 30
years and 3.782 (95% CI 1.127-12.686) in women over 35. Weight gain in the
group with GDM was significantly higher than in the group that included
pregnant women without GDM (p <0.01). Considering the high risk of GDM with
excessive gestational weight gain, educational nutrition programs should be
established for the fertile-age population, not only to prevent obesity but
also to prevent excessive weight gain during pregnancy.
Effect of Thermocycling, Degree of Conversion, and Cavity Configuration on the Bonding Effectiveness of All-in-One Adhesives
Authors: El-Damanhoury HM , Gaintantzopoulou M
Published: March 2015

The aim of this study was to compare five all-in-one bonding agents with respect to microleakage, microtensile bond strength (μTBS), degree of conversion (DC) and the impact of cavity configuration. The materials tested were Adper Easy Bond, Clearfil S3 Bond, iBond, Optibond All-in-One, Xeno IV, and Adper Single Bond Plus as a control. The DC of each adhesive was measured on the surfaces of dentin discs (n=5) by attenuated total reflectance Fourier transform infrared spectroscopy. One hundred and forty-four extracted human molars were randomly divided and assigned to one of the five tested adhesives and the control group. The μTBS to dentin was measured on flat occlusal dentin with and without thermocycling and to the gingival floor dentin of class II cavities (n=8). All specimens were restored with Filtek Z250 resin composite. Class II samples were immersed in a 5% methylene blue dye solution for 24 hours, and microleakage was examined under a stereomicroscope. Micromorphological analysis of demineralized/deproteinized specimens was done using scanning electron microscopy. The DC and microleakage data were statistically analyzed by one-way analysis of variance (ANOVA) and μTBS data by two-way ANOVA followed by a Bonferroni multiple comparison post hoc test (α=0.05) and Weibull-distribution survival analysis. The relation between different variables and μTBS and microleakage was tested by the Pearson correlation coefficient and regression statistics. A moderate direct relation between DC and μTBS durability was found for all the adhesives tested. Significant wide variations exist among the results obtained for single-bottle adhesives tested regarding their μTBS and microleakage. Some of the all-in-one materials tested have shown significantly inferior results under a high C-factor or after aging. The use of these materials should be carefully considered.
Elektriliini trasside puitse biomassi modelleerimine/ Modelling of woody biomass on electricity pylons
Authors: Mitt Risto , Padari Allar , Samsonov Marti
Published: March 2015

The aim of this study was to model regression equations for the volume of oven dry stems, branches and leaves/needles in relation to tree height and to estimate the growth of biomass on electricity pylons. A formula of linear regression between moisture and acidity of soil was also modeled in order to assess the volume of woody biomass. In 2009, 42 sample areas with 126 circular plots were created. The sample areas were located all over Estonia in order to render a wide representation of soil types. The plots were re-measured in 2012. The sample areas consisted of three circle plots divided into a series of 4m wide, distance between centers of circles was 10m. One hundred twenty two trees from the sample areas were felled in 2009 and 182 in 2012. The data of sample trees were analyzed and regression equations to estimate the growth of trees in sample areas were calculated. The average oven dry mass for stems and branches was 1970 kg/ha, with a maximum of 10,520 kg/ha. Leafless biomass growth was also calculated for each sample plot: the largest growth (in carbon soil) was 1562 kg/ha/y. The density of trees in the sample plots were the biggest influence on annual growth. The number of trees varied up to 200,000 with an average of 48,000 trees per hectare. The study also includes the results of research into the relationship between biomass production and soil properties.
Sorption ability of the soil and its impact on environmental contamination
Authors: Hřibová Šárka , Zlámalová Gargošová Helena , Vávrová Milada
Published: March 2015

From the physical point of view, soil is a heterogenic polydisperse system. It often becomes a place of a secondary contamination during extinguishing uncontrolled areal fires in nature. Foam extinguishing agents (FEAs), used at these events, basically contain surface active substances and perfluorinated compounds. These tend to be captured in the soil matrix due to their specific properties. Contaminants could be partly flushed out with rainwater, which causes several times dilution of contamination and lower ecotoxic activity. However in the dry season, foam solution infiltrates into the bed soil without any dilution. This study deals with the direct influence of soil the sorption complex on ecotoxicity of five selected FEAs, i.e. Expyrol F 15, Finiflam F 15, Moussol APS F 15, Pyrocool B and Sthamex F 15. The substances tested were prepared in concentration of work solution and then applied on standard soil matrix LUFA 2.3. For experimental purposes, a column infiltration apparatus was designed and compiled. Filtrates were collected and then tested using the plant organisms Sinapis alba and Allium cepa L. The study compared ecotoxicologic effects of filtrates with an original work solution. Moussol APS F 15 seems to be the least ecotoxic of the FEAs tested. A direct influence of soil sorption complex onto ecotoxicity reduction was also established. This finding demonstrates the sorption ability of soil particles and ion exchange activity of the soil matrix. It is a positive finding for biota of aquatic environment, yet at the expense of those in soil
European Renal Best Practice Guideline on Kidney Donor and Recipient Evaluation and Perioperative Care
Authors: Spasovski Goce , Cochat Pierre , Hj Claas Frans , Heemann Uwe , Pascual Julio , Dudley Chris , Harden Paul , Hourmant Marivonne , Maggiore Umberto , Salvadori Maurizio , Squifflet Jean-Paul , Steiger Jurg , Torres Armando , Viklicky Ondrej , Zeier Martin , Vanholder Raymond , Van Biesen Wim , Nagler Evi , Abramowicz Daniel
Published: March 2015

The Clinical Practice Guideline on evaluation of the kidney donor and transplant recipient was developed following a rigorous methodological approach aiming to provide information and aid decision-making to the transplant professionals. Thus, this document should help caregivers to improve the quality of care they deliver to patients with no intention it is defined as a standard of care.

In this short version of the guidelines we present 112 statements about the evaluation of the kidney transplant candidate as well as the potential deceased and living donor, the immunological work-up of kidney donors and recipients and the perioperative recipient care.

The extended version of the guidelines with methods, rationale and references is published in Nephrol Dial Transplant (2013) 28: i1-i71; doi: 10.1093/ndt/gft218 and can be downloaded freely from http://www.oxfordjournals.org/our_journals/ndt/era_edta.html.
Quality of Life in Children with Asthma as a Marker of Clinical Stability
Authors: Cvejoska-Cholakovska Valentina , Vlaski Emilija , Velic-Stefanovska Vesna
Published: March 2015

Introduction. In order to improve asthma control, in the last decades an emphasis has been put on the assessment of quality of life (QL). The aim of the study was to assess the role of the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) in order to assess the QL as a marker of clinical stability in asthmatic children.

Methods. A total of 64 asthmatic children aged 7-17 years treated in an outpatient/hospital facility within the University Children’s Hospital in Skopje during 2 years were investigated. The children were assessed 3 times during a period of 3 months. To assess the asthma control the Clinical Stability Score (CSS) was used, and for the assessment of the QL the Macedonian version of the PAQLQ from Elizabeth Juniper was used, consisting of 23 questions organized into three domains: symptoms, activities, and emotions. The data were statistically analyzed using Statistica for Windows, version 7.0 and SPSS 14.

Results. An increase in the average values of the PAQLQ scores was established, which means better control of asthma by the end of the 3-month follow-up. There was no statistically significant difference in the QL changes and the age of asthmatic children regarding all three domains and the overall score. Better PAQLQ scores were detected in children with better CSS. A significant improvement of all the PAQLQ scores in the case of beginning the inhaled corticosteroid therapy during the study was found. According to CSS, all of the children were classified as stable (good QL) at the end of the study compared to 78% stability at the beginning of the study.

Conclusions. The Macedonian version of the PAQLQ can be used for assessment of the effects of anti-inflammatory therapy and for attainment of complete asthma control in children between 7 and 17 years of age.
Physical Activity as a Risk Factor for Hypertension and Target Hypertensive Eye Damage in Two Ethnic Groups in Macedonia
Authors: Stojanovski Zoran
Published: March 2015

Introduction. Hypertension is one of the most common chronic, noncommunicable diseases, and it is strongly associated with cardiovascular disease incidence. Lifestyle modifications are most important in HTA management, and physical activity (PA) is crucial among them. It is very difficult to give general recommendation for intensity and duration of the PA, because of the needs to make complete patient evaluation before PA is advised. The general recommendation in most of the national guidelines is to start with moderate PA, 40 min/per day, several times a week. The objectives of our study were: comparison of the physical activity, as a risk factor for hypertension in two ethnic groups in Macedonia, and comparison of the intensity of the target eye damage in the hypertensive subjects in two ethnic communities in Macedonia.

Methods. We performed a cross-sectional study with hypertensive Roma patients as a target group, and an equal number of subjects of Macedonian nationality as controls. For both groups we completed a questionnaire where we evaluated the PA. The target eye damage was analyzed according to the Keith-Wagener-Barker categorisation.

Results. Hypertensive patients exercised significantly less, or had no physical activity compared with the controls.

Conclusions. Physical inactivity is a potential risk for HTA in Roma population. This is a possible cause for the early development, and more severe stage of HTA in Roma ethnic groups, and more intensive target eye damage caused by HTA.
Evaluation of the Effectiveness and Safety of Basal Based Therapy with Insulin Glargine and Prandial Insulin in Patients with Type 2 Diabetes Poorly Controlled with Premixed Insulin
Authors: Pemovska Gordana , Petrovski Goran
Published: March 2015

Introduction. Type 2 diabetes mellitus (T2DM) is a progressive disease, requiring treatment intensification and exogenous insulin therapy in many patients. The aim of the study was to evaluate the effectiveness and safety of insulin glargine in combination with prandial insulin in poorly controlled type 2 patients previously treated with premixed insulin.

Methods. A total of 200 type 2 diabetic patients in Macedonia (male 37.5%; female 62.5%, aged 61.1±0.5 years) poorly controlled (HbA1c>7%) were included in this observational multicenter prospective study. Before enrolment, all patients were treated with premixed insulin (88% with 2 and 12% with 3 injections per day, respectively). During the study, patients received once-daily glargine plus pre-prandial short-acting insulin analogues at investigators’ discretion. Primary end-point included percentage of patients achieving HbA1c <7% at study end. In addition, changes in mean HbA1c and fasting plasma glucose (FPG) during the study duration as well as frequency of hypoglycaemic episodes were evaluated.

Results. After 9 months of follow-up, 100 patients (50%) achieved target HbA1c <7%. Mean HbA1c decreased from 9.5±1.5% at the beginning to 6.9±0.8% (p<0.001) at study end and mean FPG decreased from 11.0±3.3 mmol/l to 6.1± 0.9 mmol/l (p<0.001). 50.5% of the patients were treated with basal insulin in combination with OADs and 49.5% required addition of one or more prandial insulin injections. No episodes of severe hypoglycaemia were documented.

Conclusions. Basal based insulin treatment with insulin glargine alone or in combination with prandial insulin improved glycaemic control in type 2 diabetics previously poorly controlled with premixed insulin with a low risk of hypoglycaemia and weight gain.
Differentiating Vascular Dementia from Alzhemer’s Disease with Brief Cognitive Tests
Authors: Barbov Ivan , Georgievska Ana , Arsova Slavica , Lazarova Snezhana , Petrov Igor
Published: March 2015

Introduction. Alzheimer’s disease (AD) and vascular dementia (VaD) are the most common causes of dementia in the elderly. The aim of this study was to investigate the diagnostic value of brief cognitive tests investigate the diagnostic value of brief cognitive tests in differentiating vascular dementia from Alzheimer’s disease.

Methods. Fifteen patients with mild VaD, 15 patients with probable AD and 30 healthy controls, matched for age, education and dementia severity, were submitted to the following cognitive tests: clock drawing (free drqawing and copy), category of letter fluency, delayed recall test of figures and the EXIT 25 battery.

Results. VaD patients performed worse than AD patients in category fluency (p=0.014), letter fluency (p=0.043) and CLOX 2 (p=0.023), while AD cases performed worse than VaD patients in delayed recall (p=0.013). However, Receiver Operating Characteristic (ROC) curves for these tests displayed low sensitivity and specificity for the differential diagnosis between VaD and AD.

Conclusions. Altough the performance of VaD and AD patients was significantly different in some cognitive tests, the value of such instruments in differentiating VaD from AD proved to be very limited.
Traffic Congestion Evaluation Method for Urban Arterials
Authors: Sun Daniel J. , Liu Xiaofeng , Ni Anning , Peng Chunlu
Published: March 2015

Quantitative analysis of traffic conditions provides a benchmark for evaluating traffic states for effective operation and management. Most existing studies focus on measuring congestion in freeway continuous traffic flow. This paper quantifies states of urban interrupted traffic flow by using field traffic data from arterial roads in Changzhou, Jiangsu Province, China, as a study case. Development of the average congestion index considered traffic volumes on various segments to reflect the congestion state of the entire road. The congestion travel rate reflected the difference between the studied state and the free-flow state. The two indexes were adopted for measuring congestion quantitatively for both weekday (March 24, 2010) and weekend (March 28, 2010) traffic. In addition, the fuzzy clustering method was used to obtain threshold values for various traffic states, and three states were proposed from the empirical study on traffic conditions in Changzhou. Under this classification, congestion quantifications of field-observed trends from both the weekday and the weekend were found to be consistent with the definitions of the Urban Traffic Management Evaluation System of China. This finding further validated the effectiveness of the proposed average congestion index indicator.
Assessment of Level of Service on Freeways by Microscopic Traffic Simulation
Authors: Geistefeldt Justin , Giuliani Stefan , Vortisch Peter , Leyn Ulrike , Trapp Roland , Busch Fritz , Rascher Andrea , Celikkaya Nihan
Published: March 2015

Analytical methods for the assessment of traffic flow quality on freeways are valid for standard types of basic, merge, diverge, and weaving segments. For more complex freeway facilities, microscopic traffic flow simulation is widely used. In this case, the definition and the computation of the level of service must be compatible with the analytical methods. For the forthcoming edition of the German Highway Capacity Manual, standards and user guidance for the application of microscopic traffic flow simulation tools for quality of service assessment on freeways were developed. For typical freeway segments, standard parameter sets for the simulation tools VISSIM, AIMSUN, PARAMICS, BABSIM, and Simulation of Urban Mobility were developed. This study applied these simulation tools for a diverge with a two-lane exit ramp. The results show that the simulation results represent the manual's design capacities well.
Method for Scenario Selection and Probability Adjustment for Reliability and Active Traffic Management Analysis in a Highway Capacity Manual Context
Authors: Aghdashi Seyedbehzad , Schroeder Bastian J. , Rouphail Nagui M.
Published: March 2015

This paper presents an optimization-based probability adjustment approach that enables an analyst to minimize the error and bias in estimating freeway reliability performance measures by using a small sample of reliability scenarios. The freeway facilities travel time reliability methodology proposed for the Highway Capacity Manual 2010 can produce up to 24,000 scenarios to be evaluated for estimating the travel time distribution. The methodology uses a deterministic scenario generation approach to account for any possible operational condition of freeway facilities. In addition to processing time considerations, the large number of scenarios poses analytical challenges because ( a) a detailed assessment and scrutiny of individual scenarios cannot be performed and ( b) the customized selection of active traffic management is infeasible. The proposed method allows the analyst to adjust the selected scenario probabilities to estimate the real-world freeway performance measure better with a manual biased sample. The biased sampling probability adjustment method is applied to two real-world case study examples. These illustrate that the population travel time distribution can be approximated adequately through the probability adjusted sample. Findings from this research have implications for proposed reliability and active traffic management methodologies in the Highway Capacity Manual 2010. The number of scenarios can be greatly reduced from several thousand to less than 100 while maintaining the shape of the reliability distribution and key performance measures of the scenario population.