bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Field Data Analyses of Ball-Sealer Diversion
Authors: Nozaki M.. , Zhu D.. , Hill A.D.. D. 
Published: July 2013

Summary
Diversion methods are routinely used in both matrix-acidizing and fracturing-stimulation treatments. The diversion methods are categorized into chemical diversion and mechanical diversion. In this study, we focus on one of the classical mechanical-diversion methods, ball sealers. Ball-sealer diversion is used in cased and perforated wells to divert stimulation fluids by temporarily blocking perforation holes in the casing with rubber-coated balls. This diversion method can be very effective, particularly with highrate injection, but no general methodology is available to design ball-sealer diversion, or to evaluate its effectiveness from the treating rate and pressure record.
Although some design methodologies, such as the use of buoyant ball sealers to improve the ball-sealer efficiency, have been suggested, no model has been presented for determining how many balls seat on the perforations. In this paper, experimental data from an extensive series of full-scale flow experiments conducted by Bern (1993) and Bern and Lewis (1992a, b) were analyzed. We summarized several features of the ball sealers which are not presented in the literature. Also we used the procedure presented by Brown et al. (1963) to evaluate the statistical nature of the ball behavior in the experimental results. The experiments were designed to minimize the scatter of data. However, the seating process was found to still be statistical. We developed an empirical correlation for ball-sealer performance on the basis of the experiments.
We also analyzed one field acid-fracturing treatment where ball sealers were used as a diversion method. The analyzed data were then compared to the experimental results. A similar trend in seating behavior was observed.
Interpreting Uncemented Multistage Hydraulic-Fracturing Completion Effectiveness By Use of Fiber-Optic DTS Injection Data
Authors: Holley E.H.. H. , Molenaar M.M.. M. , Fidan E.. , Banack B.. 
Published: July 2013

Summary
Tight gas, low-permeability reservoirs offer a tremendous challenge with respect to effectively completing and draining a target reservoir. Openhole-packer completions in horizontal wells offer a cost-efficient means of accessing the entire lateral section, assuming the target pay can be effectively stimulated. The challenge with openhole completions compared with more-conventional cased, cemented, and limited-entry perforated completions is understanding and controlling hydraulic-fracture geometry—specifically, the number and location of fracture-initiation points and the fracturing-fluid flow into the near-wellbore (NWB) region of the reservoir.
Fiber-optic-based distributed temperature sensing (DTS) offers a method for identifying, quantifying, and evaluating the NWB fracture geometry, the fracturing-fluid distribution in these broad openhole sections, and overall stimulation effectiveness. DTS can also reveal success or issues with respect to effective zonal isolation when using mechanical isolation during the hydraulic-fracturing process. In this particular case study, a lateral well in a basin-centered gas area was completed with swell-packer interval isolation by use of fracture sleeves for reservoir access. By coupling fracture-treatment responses and openhole log characteristics with the NWB DTS data during pumping and warm back, an integrated assessment of the completion stimulation effectiveness and efficiency was performed.
The end result of this assessment provided an improved understanding of the current completion performance and allowed optimization of openhole completion projects for future wells in this same area.
Synthesis and antimicrobial studies of some Mannich bases carrying imidazole moiety
Authors: Frank Priya V. , Manjunatha Poojary Mahesha , Damodara Naral , Chikkanna Chandrashekhar 
Published: July 2013

3
Starting from 2-methyl-4-nitro-imidazole, new 5-(2-methyl- 4-nitro-1-imidazomethyl)-1,3,4-oxadiazole-2-thione () was synthesized and was subjected to Mannich reaction with appropriate amines to yield a new series of 3-substituted aminomethyl-5-(2-methyl-4-nitro-1-imidazomethyl)- 1,3,4-oxadiazole-2-thiones (4a-j). The structure of the title compounds was elucidated by elemental analysis and spectral data. The newly synthesized Mannich bases were screened for their antibacterial and antifungal activity. Many of these compounds exhibited potent antifungal activity.
Infrared Sensor to Predict Atmospheric Visibility and Rainfall Rate
Authors: Holejko Krzysztof , Czarnecki Tomasz , Perlicki Krzysztof 
Published: July 2013

Abstract
The presented paper describes an instrument called Aurometer which was designed for both atmospheric visibility and rainfall rate measurement. The principle of operation of Aurometer is based on determining the amount of light scattered by particles in the air that passes through the sample volume. The achieved results show that simultaneous estimation of the atmospheric visibility and rainfall rate is possible.
A Circuit Model to a Directive Triangular EBG Antenna
Authors: Ferchichi Abdelhak , Gharsallah Ali 
Published: July 2013

Abstract
In This paper, we propose a directive triangular EBG antenna. This approach is derived from using an EBG surface near to a triangular patch with two grilles. The antenna frequency chosen is the 2.45GHz. The directive antenna is simulated by using HFSS and Electrical model. This proposed antenna presents a very high directivity.
A Contribution to the System-Theoretic Approach to Bandwidth Estimation
Authors: Borys Andrzej , Wasielewska Katarzyna , Rybarczyk Dariusz 
Published: July 2013

Abstract
The network calculus provides a theoretical background for description of traffic in computer networks. Using this tool in explanation of the so-called pathchirp method of measuring the available bandwidth, the validity and range of application of some relationships exploited are verified in this paper. The derivations are carried out in a wider context than that considered in a recent paper by Liebeherr et al. published in IEEE/ACM Transactions on Networking on network bandwidth estimation, providing thereby new insights and outcomes. These results, summarized in a table, show a means of bounding the service curve, depending upon its convexity or non-convexity property assumed and upon the linearity or non-linearity of a network considered. Moreover, it is shown here that the nonlinear network example analyzed by Liebeherr et al. can be viewed equivalently as a linear parametric network. For this network, the behaviour of the cross traffic is considered in a more detail, too.
Wireless Communication Solution for Distributed Structural Health Monitoring
Authors: Andrzejczak Artur , Łeczycki Paweł , Makowski Maciej , Pekosławski Bartosz , Pietrzak Piotr , Napieralski Andrzej 
Published: July 2013

Abstract
This paper describes a design of wireless distributed SHM (Structure Health Monitoring) system with a particular emphasis on comparison of wireless communication standards. The presented solution is being deployed in the TULCOEMPA project. Several wireless communication standards are compared, with their benefits, disadvantages and typical areas of application. A choice of proper ISM (Industrial Scientific Medical) band and reasons for use of Wireless Sensor Networks are also discussed. The last part of this paper presents the proposed structure and designed prototype. The chosen architecture of the system and the program algorithm used for communication and measurements are described.
Investigation and Study of Mode Splitting in Near Field Inductive Communication Systems
Authors: Thanh Hoa Doan , Agbinya Johnson I. 
Published: July 2013

Abstract
Frequency splitting is a near field inductive communication phenomenon where the resonant frequency divides into many separate frequencies or to different modes. In this paper, we show that this phenomenon depends on the coupling coefficients or the natural response of the circuit by using the circuit theory to derive these splitting frequencies. Also, the rules for the general matrix that is used to solve for splitting frequencies are also demonstrated clearly. Mode splitting is observed for peer-to-peer, three coils and four coil systems due to the existence of the nearest and second neighbour interactions. In particular, two, three and four modes have been analysed for two, three, and four coil systems respectively. However, the number of modes for these systems can be changed according to the degree of coupling. The differences in the resultant splitting frequencies with and without the second neighbour interaction are shown in the simulation results. Furthermore, we assess the system performances regarding to power efficiency through the inductive transfer functions. Besides, either coupling coefficients at resonance or the simplified transfer functions in some specific scenarios can be obtained by having an insight into these transfer functions. Finally, we recognise and propose that splitting frequency phenomenon can be deployed to transmit signals at many frequencies concurrently.
Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow
Authors: Machalinska-Murawska Justyna , Szydłowski Michał 
Published: July 2013

Abstract
Two explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free surface water flow. Two numerical simulations of flow with different hydraulic characteristics were performed - the first one for the extreme flow of the dam-break type and the second one for the simplified flood wave propagation problem. The computational results are compared to each other and to arbitrary solutions.
The effectiveness of different types of verbal feedback on learning complex movement tasks
Authors: Niznikowski Tomasz , Sadowski Jerzy , Mastalerz Andrzej 
Published: July 2013

PurposeThe purpose of the study was to assess the effectiveness of different types of verbal feedback in the learning of a complex movement task.MethodsTwenty university students took part in a six-week training course learning how to correctly execute the vertical jump. The participants were randomly assigned to one of three groups: Group E&P received verbal feedback on errors made during movement execution and on how to improve, Group P obtained verbal feedback only when they correctly performed the task, and Group E was provided with verbal feedback only when an error was made. Performance was measured on three separate occasions, before the training course (pre-training), one day after (post-training) and seven days after completing the course (retention) by executing the vertical jump in front of three gymnastic judges who scored their performance on a scale of 1 to 10. Jump kinematics were also measured pre-training and post-training by recording landing force and flight time on a force platform.ResultsPost-hoc comparison indicated that a significant improvement in performance was observed only in the group receiving verbal feedback on errors (E). Judges’ scores received in post-training were significantly higher than those measured pre-training (10.3 %; <i>p</i> < 0.0003) and further increased to 14.4 % in the retention test (<i>p</i> < 0.0001). Judges’ scores for the groups receiving verbal feedback on errors and correctness (E&P) and only correctness (P) improved insignificantly.ConclusionsProviding too much verbal feedback when learning the vertical jump turned out to be less effective than providing limited verbal feedback only when errors were made.
On the possibility of applying achievement goal theory in competitive sports
Authors: Kuczek Piotr 
Published: July 2013

PurposeThere exist numerous empirical proofs as well as theoretical bases showing that task motivational orientation and task climate allow students and athletes to function better and be more efficient. What is not certain is whether the same applies to athletes competing at the professional level. The aim of this study was to analyze whether task orientation and task-oriented climate help professional athletes avoid experiencing high levels of anxiety, thereby providing a favorable foundation for performance in high-level competition.MethodsBasketball players from the Polish II League (amateur) and Extraleague (professional) were surveyed. Motivational orientation, motivational climate, and anxiety levels were measured by the Perception of Success Questionnaire (POSQ), Perception of Significant Others’ Sport Success Criteria Questionnaire (PSOSSCQ), and Sport Anxiety Scale (SAS), respectively.ResultsThe reliability of the research tools on a Polish population was confirmed. Motivational climate was associated with motivational orientation; task orientation and a task-oriented climate were found to not reduce anxiety levels.ConclusionsThe results do not confirm the application of achievement goal theory in high-level competitive sports.
Gait asymmetry during dual-task obstacle crossing in the young and elderly
Authors: Rocha Emmanuel S. da , Machado Álvaro S. , Franco Pedro S. , Guadagnin Eliane C. , Carpes Felipe P. 
Published: July 2013

PurposeTo evaluate gait asymmetry during obstacle crossing by young and elderly adults performing normal and dual-task gait.MethodsTen healthy young adults and ten elderly adults with mild cognitive impairment performed a gait protocol by stepping over a foam obstacle during normal gait and while performing a secondary task (Stroop task). Sagittal kinematics of the lead and trail limbs were analyzed. Statistical procedures involved analysis of variance and t tests at a significance of 0.05.ResultsMany of the kinematic variables presented a main effect for group (young adults vs. elderly adults), where the elderly featured poorer gait performance. It was observed that gait velocity during obstacle crossing in normal and dual-task gait was similar between the preferred and non-preferred limbs in both the young and elderly. However, the elderly were slower during normal and dual-task gait. A main effect for the dual-task condition was observed. Kinematic asymmetries for obstacle crossing were more frequent in the elderly and especially during the dual-task condition.ConclusionsThe results suggest that the elderly may require more compensatory adjustments after crossing an obstacle. The asymmetries observed among the elderly may contribute to higher risk of falling during perturbed gait.
Differences in the direction of effort adaptation between mountain bikers and road cyclists
Authors: Zatoń Marek , Dąbrowski Dariusz 
Published: July 2013

PurposeDifferent forms of cycling require the use of different abilities and skills. The aim of this paper was to attempt to identify differences in the directions and dynamics of the body’s adaption to training in road (ROAD) and mountain (MTB) cyclists.MethodsResearch was performed on a group of competitive road (<i>n</i> = 25) and mountain (<i>n</i> = 25) cyclists, mean age 16.96 ± 0.78 years presenting maximal oxygen uptake values of 4.45 ± 0.47 L/min-1. Body composition and physiological and biochemical parameters at rest, during exercise, and during restitution (cool down) were determined. Exercise was performed on a cycle ergometer in the form of a progressive load test. Analysis of the results included cluster analysis and basic statistical methods.ResultsCluster analysis indicated that the amount of work performed during the progressive load test was a universal indicator of physical fitness. The level of base excess (BE) in the 3rd min of restitution had a large influence on the remaining parameters in both groups. Training adaptation in MTB were manifested through increased values of maximum heart rate, blood oxygen saturation, oxygen partial pressure, and lactate and BE levels in the blood, as well as a reduction in blood pH and body mass. Conversely, in ROAD, adaptation to effort was evidenced by increased maximum values of oxygen uptake, minute ventilation, cardiac output and the rate of carbon dioxide elimination as well as an increase in hematocrit count and lean body mass.ConclusionsAdaptation to training by road cyclists is primarily evident in the development of aerobic capacity. Mountain biking induces adaptive changes in the development of anaerobic capacity by increasing the buffer capacity of the blood and muscles, as well as the development of the oxygen transportation system.
Comparison of accuracy of various non-calorimetric methods measuring energy expenditure at different intensities
Authors: Durkalec-Michalski Krzysztof , Woźniewicz Małgorzata , Bajerska Joanna , Jeszka Jan 
Published: July 2013

PurposeThe purpose of the study was to evaluate the accuracy of three non-calorimetric methods’ measurements of energy expenditure (EE) in laboratory conditions and to compare the results obtained by each method in free-living condition in a group of adult subjects.MethodsMeasurement was performed on 20 individuals aged 19-39 years. An assessment of EE at different intensities of physical activity was conducted by: monitoring heart rate with a S-610 Polar Sport Tester (HRM), measuring body movement by an ActiGraph GT1M accelerometer (AM), and recording METs (MR) by a physical activity questionnaire, for different activities (leisure and exercise) at various intensities in laboratory and free-living conditions. Indirect calorimetry (Cosmed K4b2 respirometer) was used as a reference standard.ResultsThe most reliable tool for EE assessment was HRM (100% accurate). AM overestimated EE (about 60%) for activity at moderate-intensity and underestimated EE (about 40%) at vigorous-intensity. MR overestimated the results, with measurement errors increasing with an increase in physical activity intensity (about 40-120%).ConclusionsAlthough AM and MR provided less accurate results than HRM in laboratory conditions, there were no significant differences between the three methods (HRM, AM and MR) when total daily energy expenditure was calculated for the participants in free-living condition.
Analogy vs. technical learning in a golf putting task: an analysis of performance outcomes and attentional processes under pressure
Authors: Schücker Linda , Hagemann Norbert , Strauss Bernd 
Published: July 2013

PurposeIt is assumed that analogy learning helps prevent individuals from choking under pressure by limiting the conscious control of movements when performing in high-pressure situations. The aim of the study was to extend the application of analogy learning to golf putting and include an assessment on the proposed mechanisms of analogy learning and performance under pressure.MethodsGolf novices learned a putting task either by technical instructions or with analogy. After the learning phase, the participants were tested under low- and high-pressure conditions. Attentional focus was measured using a dual-task paradigm based on a skill and an externally focused task.ResultsBoth groups showed an increase in putting accuracy under pressure while performance in both dual-tasks decreased under pressure. Despite a difference in verbal knowledge, no group differences were found in putting or dual-task performance.ConclusionsThe results suggest that it does not matter if the skill is learned technically or by analogy with regard to performance under pressure
Globalization in the Context of Islamic Theology
Authors: Bicer Ramazan 
Published: July 2013

AbstractGlobalization is not a new phenomenon, but it is being expressed in a new way. It is a phenomenon all over the world; not only does it have a deep impact on the economy, it also affects all countries, all aspects of our daily life, such as our society, culture, economy, and religion. The value of globalization is the subject of debate: it has positive and negative effects. Some religious problems have emerged from globalization: secularism, individualism, New Age religious movements, the rise of religious radicalism, and the growth of religious commerce.Theologians view their religion as a universal that can live inand adapt all ages all of the time and in any social surrounding. Their religion is weatherproof. According to this approach, theologians have to find a persuasive solution to global theological problems.
The notion of Dhikr in Islamic Mysticism
Authors: Salih Jusuf 
Published: July 2013

AbstractThe word dhikr is probably the most frequently used form of prayer in Islamic mysticism. This term includes all kinds of mentioning, worshiping, and remembering God and can be performed out loud or silently, according to the place or the character of the mystic. The Qur’an sometimes refers to itself by this term, and it is sometimes attributed to the Prophet Muhammad since he was as a “reminder.” Muslim mystics believe that people are directed away from the nucleus of their being and that their consciousness is imprisoned in some kind of delusion and forgetfulness (ghafla). Therefore they should “remind” (dhikr) and be reminded constantly so that they will “remember” what they have “forgotten.” When dhikr is performed, that is an indication in the person’s heart that he or she has not forgotten God but is aware of his or her weaknesses and need for constant guidance. Consequently, this “remembrance” is a spiritual ornament that ought to be deeply entrenched in the hearts of all human beings: it is a way to happiness; a lock opener on the humans’ journey toward the Divine love; it is the foundation and cornerstone of good deeds and excellent conduct.
Critical study of the erroneous attribution of the book Shajarat al-Kawn to Ibn ‘Arabī instead of to Ibn Ghānim al‐Maqdisī
Authors: Mdaghri Younes Alaoui 
Published: July 2013

AbstractShajarat al-kawn, (The Tree of the Universe) is a beautiful short treatise on Islamic mysticism that describes the universe and its true origin, the role and place of Prophet Muhammad (peace be on him), and his central place in the sacred presence. According to some manuscripts from the 19th century (13th century A.H.), it is attributed to Muhyī d- Dīn Ibn ‘Arabī (d. 638 A.H./1240) . All scholars endorsed this attribution and it was conveyed via fifteen commercial book-prints.The study by Arabic scholars and orientalists and some translations led to doubt about the origin of the treatise. This was the start of an adventure because what was supposed to be known up to now would become questioned.During my research, I scrutinised two different unknown manuscripts of Shajarat alkawn. There was also a third, very old, manuscript written in the year 835 A.H. All these manuscripts refer to the author and poet ‘Izzu d-Dīn ‘Abd as-Salām Ibn Aḥmad Ibn Ghānim al-Maqdisī (d.678 A.H./1280) and not to Ibn ‘Arabī.Furthermore, I found some proof in the biographical history and the style of writing that pointed to Ibn Ghānim as the author. I came to the conclusion that the work was actually written by ‘Izzu d-Dīn ‘Abd as‐Salām Ibn Aḥmad Ibn Ghānim. From the results of my research, we can conclude that the book Shajarat al-kawn is by Ibn Ghānim and not Ibn ‘Arabī.This study consists of two parts. The first is: How did this treatise, Shajarat al-kawn, come to be universally attributed to Ibn ‘Arabī? The second is a discussion of the doubts that the treatise Shajarat al-kawn was written by Ibn ‘Arabī. This discussion consists of four topics: 1) the problem of copying manuscripts attributed to Ibn ‘Arabī, 2) the catalogues that attributed Shajarat al-kawn to Ibn ‘Arabī, 3) comparison of the text of the Shajarat al-kawn in both content and format with Ibn ‘Arabī and Ibn Ghānim, and 4) the studies and translations of the Shajarat al-kawn attributed to Ibn ‘Arabī.”