bluuebunny/crossref_metadata_2025 huggingface dataset:
How sensitive teachers are in elementary and secondary science classes in terms of technology and environmental ethics
Authors: Ceyhan Busra , Sahin Nurettin
Published: January 2018

This study aimed to determine the sensitivity of science teachers towards technology and environmental ethics. The study group comprised science teachers and classroom teachers working in the city of Mugla in 2016â€“2017, and data were collected using a 36 item Likert technology and environmental ethics questionnaire. Cronbachâ€™s alpha reliability coefficient of the questionnaire was calculated as 0.8. For analysis of data, percentages, arithmetic mean, standard deviation, t-test, oneway variance analysis and frequencies were used in the SPSS 20 program package. The responses given to the questionnaire items were analysed in terms of the branches of the participating teachers. The responses given to the items regarding benefits to living things differ significantly in favour of the classroom teachers. The item with which the participating teachers agreed to the highest degree was, â€˜Teaching individuals how to utilise resources most effectively by getting to know environment should be a part of educationâ€™. Keywords: Ethical sensitivity, teachers, technology ethics, environmental ethics.
Evaluation of class passing conditions of the failed students from the viewpoints of Education Ministry Officials, school administrators, teachers and parents
Authors: Kalkan Umit , Koc Ahmet , Karadag Mehmet
Published: January 2018

This survey aims to evaluate the social promotion of class-repeating students, applied with the changes in regulations made by the TRNC Ministry of National Education, for promotion to a higher grade from the viewpoints of Ministry of Education and school administrators, parents, teachers and students. For this survey, the semi-structured qualitative interviews were used. A total of 100 participants were interviewed, including school administrators, teachers and students in a high school. Based on the findings, we concluded that social promotion of the failed students to a higher grade is a defective practice. Also, it is hard in Cyprus to try to fulfill learning deficiencies in the higher grade. Lastly, the ongoing practice of social promotion enforced in recent years was favoured, because the authorities aimed at preventing possible overcrowding in lower grades rather than meeting the requirements of contemporary educational system. Thus, this educational policy in concern has numerous disadvantages. Keywords: class passing, Ministry of Education, school administrators, teachers, parent.
Investigating the impact of main factors on problem-solving confidence using cooperative learning: A case study
Authors: Mafakheri Shiva
Published: January 2018

Low self-confidence in problem solving is one of the main issues in terms of mathematics education between high school students, and this issue led to decreasing the mathematic learning. Mathematic educators always faced a challenge with learners for not being proactive in solving the problems and avoiding them, hence this study aimed to explore the main factors that influence self-confidence problem solving. A total of 20 questions are designed based on different literature and principle components, and confirmatory factor analysis was used for analysing the data. The results of the study indicated that the main influence factors are ability, motivation, perseverance, sense of helplessness and inhibitor. Finally, recommendation and some policies are presented to increase the self-confidence in educational system. Keywords: Mathematics education, problem solving, self-confidence, cooperative learning;
A Cosmological View on Milgrom’s Acceleration Constant
Authors: Roza Engel
Published: January 2018

In this article a two-parameter model is developed for the universe. The two parameters are the age of the universe and Milgrom’s acceleration constant. It is shown that these are sufficient to calculate the amounts of matter and dark energy in the universe, as well as the contributions of dark matter and baryonic matter in the matter part. All this, not only for present time, but also as a function of cosmological time. The developed theory gives an adequate explanation for the phenomena of the accelerated scaling of the universe and the anomaly of the stellar rotation curves in galaxies. The numerical results are in agreement with those of the Lamda-CDM model.
Cyanobacteria Scytonema javanicum and Scytonema ocellatum Lipopolysaccharides Elicit Release of Superoxide Anion, Matrix-metalloproteinase-9, Cytokines and Chemokines by Rat Microglia In Vitro
Authors: Klemm Lucas C. , Czerwonka Evan , Hall Mary L. , Williams Philip G. , Mayer Alejandro M.S.
Published: January 2018

Cosmopolitan Gram-negative cyanobacteria may affect human and animal health by contaminating terrestrial, marine and freshwater environments with toxins, such as lipopolysaccharide (LPS). The cyanobacterial genus Scytonema (S) produces several toxins, but to our knowledge the bioactivity of genus Scytonema LPS has not been investigated. We recently reported that cyanobacterium Oscillatoria sp. LPS elicited classical and alternative activation of rat microglia in vitro [1]. Thus, we hypothesized that treatment of brain microglia in vitro with either cyanobacteria S. javanicum or S. ocellatum LPS might stimulate classical and alternative activation with concomitant release of superoxide anion (O2−), matrix metalloproteinase-9 (MMP-9) and cytokines and chemokines. Microglia were isolated from neonatal rats and treated in vitro with either S. javanicum LPS, S. ocellatum LPS, or E. coli LPS (positive control) in a concentration-dependent manner for 18 hours at 35.9 °C. We observed that treatment of microglia with either E. coli LPS, S. javanicum or S. ocellatum LPS generated statistically significant and concentration-dependent O2−, MMP-9 and pro-inflammatory cytokines IL-6 and TNF-α, pro-inflammatory chemokines MIP-2/CXCL-2, CINC-1/CXCL-1 and MIP-1α/CCL3, and the anti-inflammatory cytokine IL-10. Thus, our results provide experimental support for our working hypothesis because both S. javanicum and S. ocellatum LPS elicited classical and alternative activation of microglia and concomitant release of O2-, MMP-9 and cytokines and chemokines in a concentration-dependent manner. To our knowledge this is the first report on the toxicity of cyanobacteria S. javanicum and S. ocellatum LPS to microglia, an immune cell type involved in neuroinflammation and neurotoxicity in the central nervous system. 
The Effect of Temporal Gradient of Vegetation Indices on Early-Season Wheat Area Estimation Using Random Forest Classification
Authors: Saei Jamal Abad Mousa , Abkar Ali A. , Mojaradi Barat
Published: January 2018

The early-season area estimation of the winter wheat crop as a strategic product is important for decision makers. Classification of multi-temporal images is an approach which is affected by many factors like appropriate training sample size, proper frequency and acquisition times, vegetation indices (VIs) type, temporal gradient of spectral bands and VIs, appropriate classifier and missed values because of cloudy conditions. This paper addresses the impact of appropriate frequency and acquisition times and VIs type along with the spectral and VI gradient on random forest (RF) classifier when missed values exist in multi-temporal images. To investigate the appropriate temporal resolution for image acquisition, the study area was selected on an overlapping area between two LDCM paths. In our developed method, the miss values of cloudy bands for each pixel are retrieved by the mean of k-nearest ordinary pixels. Then the multi-temporal image analysis is performed by considering different scenarios provided by decision makers in terms of desired crop types that should be extracted at early-season in the study areas. The classification results obtained by the RF decrease by 1.6% when temporally missed values retrieved by the proposed method, which is an acceptable result. Moreover, the experimental results demonstrated that if temporal resolution of Landsat 8 increased to one week the classification task can be conducted earlier with almost better results in terms of OA and kappa. The impact of incorporating VIs along with the temporal gradients of spectral bands and VIs as new features in RF demonstrated that the OA and Kappa are improved 3.1% and 6.6%, respectively. Furthermore, the obtained result showed that if only one image from seasonal changes of crops is available, the temporal gradient of VIs and spectral bands play the main role to discriminate remarkably wheat from barley. The experiments also demonstrated that if both wheat and barley merge to a single class the crop area can be estimated two months earlier with 97.1 and 93.5 in terms of OA and kappa, respectively.
An Adaptive Operation Strategy for Voltage Stability Enhancement in DMFCs
Authors: Yang Qinwen , Hu Xu-Qu , Zhu Ying , Lei Xiu-Cheng , Wang Xing-Yi
Published: January 2018

An adaptive operation strategy for on-demand control of DMFC system is proposed as an alternative method to enhance the voltage stability. Based on a single-cell DMFC stack, a newly simplified semi-empirical model is developed from the uniform-designed experimental results to describe the I-V relationship. Integrated with this model, the multi-objective optimization method is utilized to develop an adaptive operation strategy. Although the voltage instability is frequently encountered in unoptimized operations, the voltage deviation is successfully decreased to a required level by adaptive operations with operational adjustments. Moreover, the adaptive operations are also found to be able to extend the range of operating current density or to decrease the voltage deviation according to ones requirements. Numerical simulations are implemented to investigate the underlying mechanisms of the proposed adaptive operation strategy, and experimental adaptive operations are also performed on another DMFC system to validate the adaptive operation strategy. Preliminary experimental study shows a rapid response of DMFC system to the operational adjustment, which further validates the effectiveness and feasibility of the adaptive operation strategy in practical applications. The proposed strategy contributes to a guideline for the better control of output voltage from operating DMFC systems.
Heterogeneous Deep Model Fusion for Automatic Modulation Classification
Authors: Zhang Duona , Ding Wenrui , Zhang Baochang , Xie Chunyu , Liu Chunhui , Han Jungong , Li Hongguang
Published: January 2018

Deep learning has recently attracted much attention due to its excellent performance in processing audio, image, and video data. However, few studies are devoted to the field of automatic modulation classification (AMC). It is one of the most well-known research topics in communication signal recognition, which remains challenging for traditional methods due to the complex disturbance from other sources. This paper proposes a heterogeneous deep model fusion (HDMF) method to solve the problem in a unified framework. The contributions include: 1) The convolutional neural network (CNN) and long short-term memory (LSTM) are combined by two different ways without prior knowledge involved; 2) A large database, including eleven types of single-carrier modulation signals with various noises as well as a fading channel, is collected with various signal-to-noise ratios (SNRs) based on a real geographical environment; and 3) Experimental results demonstrate that HDMF is super capable of copping with the AMC problem, and achieves much better performance when compared with the independent network. The source code and the database will be publically available.
Aesthetics and Entropy III. Aesthetic Measures
Authors: Sahyun M. R. V.
Published: January 2018

We examined a series of real-world, pictorial photographs with varying characteristics, along with their modification by noise addition and unsharp masking. As response metrics we used three different versions of the aesthetic measure originally proposed by Birkhoff. The first aesthetic measure, which has been used in other studies, and which we used in our previous work as well, showed a preference for the least complex of the images. It provided no justification for noise addition, but did reveal enhancement on unsharp masking. Optimum level of unsharp masking varied with the image, but was predictable from the individual image’s GIF compressibility. We expect this result to be useful for guiding the processing of pictorial photographic imagery. The second aesthetic measure, that of informational aesthetics based on entropy alone failed to provide useful discrimination among the images or the conditions of their modification. A third measure, derived from the concepts of entropy maximization, as well as the hypothesized preference of observers for “simpler”, i.e., more compressible, images, yielded qualitatively the same results as the more traditional version of the measure. Differences among the photographs and the conditions of their modification were more clearly defined with this metric, however.
Research of Planetary Gear Fault Diagnosis Based on Permutation Entropy of CEEMDAN and ANFIS
Authors: Kuai Moshen , Cheng Gang , Pang Yusong , Li Yong
Published: January 2018

For planetary gear has the characteristics of small volume, light weight and large transmission ratio, it is widely used in high speed and high power mechanical system. Poor working conditions result in frequent failures of planetary gear. A method is proposed for diagnosing faults in planetary gear based on permutation entropy of Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) Adaptive Neuro-fuzzy Inference System (ANFIS) in this paper. The original signal is decomposed into 6 intrinsic mode functions (IMF) and residual components by CEEMDAN. Since the IMF contains the main characteristic information of planetary gear faults, time complexity of IMFs are reflected by permutation entropies to quantify the fault features. The permutation entropies of each IMF component are defined as the input of ANFIS, and its parameters and membership functions are adaptively adjusted according to training samples. Finally, the fuzzy inference rules are determined, and the optimal ANFIS is obtained. The overall recognition rate of the test sample used for ANFIS is 90.75%, and the recognition rate of gear with one missing tooth is relatively high. The recognition rates of different fault gears based on the method can also achieve better results. Therefore, the proposed method can be applied to planetary gear fault diagnosis effectively.
How Manufacturing Affects the Development of World City: A Case Study of Guangzhou in China
Authors: Li Wei , Xue Desheng , Huang Xu
Published: January 2018

In the world city theory, most researchers focus on the service sector in the urban economy and less discuss the role of manufacturing. However, the path of only emphasizing financial and corporate service could not fit the sustainability concept. Compared to Anglo-American world city, Global South’s world cities have distinct pathway to be industrialization, tertiarization and globalization. This paper adopted dynamic historic perspective with first-hand materials including in-depth interviews with managers and government officers and second-hand data including yearbook statics and economic census to closely examine the emerging world city-- ‘World Factory’ in Global South, Guangzhou in China, from 1949 to 2015, to emphasize how manufacturing affects the urban globalization through three dimensions, economic, social and spatial dimensions. To make the confirmation of the role of manufacturing in Guangzhou as sustainable world city, we find manufacturing in Guangzhou builds up the basic foundation of export-oriented economy and makes positive effects on urban economic transformation. In addition, manufacturing remains important source of employment and foreign immigration. Along with urbanization and industrialization, urban spatial expansion and aggregation changes with different urban development concept. We provide new insights on multiple globalization on manufacturing for sustainable world city.
Survey on Energy Drinks Consumption and Related Lifestyle among Students of Two Italian High Schools
Authors: Totaro Michele , Avella Michela , Giorgi Serena , Tulipani Alberto , Costa Anna Laura , Valentini Paola , Lopalco Pier Luigi , Baggiani Angelo
Published: January 2018

The European Food Safety Authority (EFSA) has identified some risk factors for the occurrence of side effects linked to energy drinks (EDs) consumption by young people. Tachycardia, sleeplessness, caffeine addiction may be caused by excessive consumption of EDs during parties, sport matches, ect. EDs consumption has been evaluated in a sample of students in Italy together with some aspects of their lifestyle. The survey was performed in two high schools from September 2014 to June 2015. 583 students between 14 to 18 years were recruited and a standard questionnaire (EFSA checklist) was used to collect information on responders characteristics, beverages consumption, EDs with alcohol, and EDs and sports. 350 out of 583 responders (60%) consumed EDs and 146 out of 583 responders (25%) reported an occasional alcohol consumption. Despite 82 out of 146 alcoholic drinkers (56%) were EDs-alcohol consumers, only 70 out of 583 adolescents (12%) reported habitual EDs consumption. Moreover, 38 out of 379 (10%) of all physically active adolescents reported frequent EDs consumption before sportive trainings. Study results highlight the need for primary prevention measures in communication campaigns and training delivered by school to limit potential health threats related to excess of EDs consumption.
Applicability of Precision Medicine Approaches to Managing Hypertension in Rural Populations
Authors: Halladay Jacqueline R. , Lenhart Kaitlin C. , Robasky Kimberly , Jones Wendell , Homan Wayne F. , Cummings Doyle M. , Cené Crystal W. , Hinderliter Alan L. , Miller Cassandra L. , Donahue Katrina E. , Garcia Beverly A. , Keyserling Thomas C. , Ammerman Alice S. , Patterson Cam , DeWalt Darren A. , Johnston Larry F. , Willis Monte S. , Schisler Jonathan C.
Published: January 2018

Background: As part of the Heart Healthy Lenoir Project, we developed a practice level intervention to improve blood pressure control. The goal of this study was: i) determine if single nucleotide polymorphisms (SNPs) that associate with blood pressure variation, identified in large case-control studies, are applicable to blood pressure control in subjects from a rural population; ii) measure the association of these SNPs with subjects’ responsiveness to the hypertension intervention; and iii) identify other SNPs that may help understand patient-specific responses to an intervention. Methods and Results: We used a combination of candidate SNPs and genome-wide analyses to test associations with either baseline systolic blood pressure (SBP) or change in systolic blood pressure one year after the intervention in two genetically defined ancestral groups: African Americans (AA) or Caucasian Americans (CAU). Of the 48 candidate SNPs, 13 SNPs associated with baseline SBP in our study; however, one candidate SNP, rs592582, also associated with a change in SBP after one year. Using our study data, we identified 4 and 15 additional loci that associated with a change in SBP in the AA and CAU groups, respectively. Our analysis of gene-age interactions identified genotypes associated with SBP improvement within different age groups of our populations. Moreover, our integrative analysis identified AQP4-AS1 and PADI2 as genes whose expression levels may contribute to the pleiotropy of complex traits involved in cardiovascular health and blood pressure regulation in response to an intervention targeting hypertension. Conclusions: Identification of SNPs associated with the success of a hypertension treatment intervention suggests that genetic factors in combination with age may contribute to an individual’s success in lowering SBP. If these findings prove to be applicable to other populations, the use of this genetic variation in making patient-specific interventions may help providers with making decisions to improve patient outcomes. Further investigation is required to determine the role of this genetic variance with respect to the management of hypertension such that more precise treatment recommendations may be made in the future as part of personalized medicine.
Process Design Aspects for Scandium-Selective Leaching of Bauxite Residue with Mineral Acids
Authors: Hatzilyberis Konstantinos , Lymperopoulou Theopisti , Tsakanika Lamprini-Areti , Ochsenkühn Klaus-Michael , Georgiou Paraskevas , Defteraios Nikolaos , Tsopelas Fotios , Ochsenkühn-Petropoulou Maria
Published: January 2018

Aiming at the industrial scale development of a Scandium (Sc)-selective leaching process of Bauxite Residue (BR), a sufficiently numerous set of process design aspects has been investigated, by appropriate exploitation of available experimental data. The interpretation of experimental data for Sc leaching yield, with sulfuric acid as the leaching solvent, has shown significant impact from acid feed concentration, mixing residence time, liquid to solids ratio, and times of leachate re-usage onto fresh BR. The thin film diffusion model, as the fundamental theory for leaching, either with constant particle size for selective leaching, or with shrinking particle size for less-, or non-, selective leaching, interprets sufficiently well the relevant experimental data. In both cases, a concept for an unyielding core supplements the basic model. Especially for the selective leaching mild conditions, the simplest model version keeps step with the experiments, since both prove 1st order kinetics, while especially for the extreme conditions including very low solvent excess, it is proposed a combined conversion rate model with diffusion and chemical reaction inside particles. The maximization of Sc recovery per unit of consumed solvent (i.e., specific recovery) emerged as highly critical for the process economics.
Real-Time Framework for Energy Management System of a Smart Microgrid Using Multiagent Systems
Authors: Netto Roberto , Ramalho Guilherme , Bonatto Benedito , Carpinteiro Otavio , de Souza A. C. Zambroni , Oliveira Denisson , Braga Rodrigo
Published: January 2018

This paper deals with the problem of real-time management of Smart Grids. For this sake, the energy management is integrated with the power system through a telecommunication system. The use of Multiagent Systems leads the proposed algorithm to find the best-integrated solution, taking into consideration the operating scenario and the system characteristics. The proposed technique is tested with the help of an academic microgrid, so the results may be replicated.
Using Concept Mapping to Develop a Human Rights Based Indicator Framework to Assess Country Efforts to Strengthen Rehabilitation Provision and Policy: The Rehabilitation System Diagnosis and Dialogue (RESYST) Framework
Authors: Skempes Dimitrios , Melvin John , Von Groote Per , Stucki Gerold , Bickenbach Jerome
Published: January 2018

Background: Access to rehabilitation is crucial for the realization of the right to health and a proper concern of global health. Yet, reliable information to guide rehabilitation service planning is unavailable in many countries in part due to the lack of appropriate indicators. To ensure universal health coverage and meet the central imperative of “leaving no one behind” countries must be able to assess key aspects of rehabilitation policy and provision and monitor how they have discharged their human rights responsibilities towards those most disadvantaged, including people with disability. This article describes the process of developing an expert guided indicator framework to assess governments’ efforts and progress in strengthening rehabilitation in line with the Convention on the Rights of Persons with Disabilities. Methods: A systems methodology - concept mapping - was used to capture, aggregate and confirm the knowledge of diverse stakeholders on measures thought to be useful for monitoring the implementation of the Convention with respect to health related rehabilitation. 56 individuals generated a list of 107 indicators through online brainstorming which were subsequently sorted by 37 experts from the original panel into non overlapping categories. 41 participants rated the indicators for importance and feasibility. Multivariate statistical techniques where used to explore patterns and themes in the data and create the indicators’ organizing framework which was verified and interpreted by participants. Results: A concept map of 11 clusters of indicators emerged from the analysis grouped into three broader themes: Governance and Leadership (3 clusters); Service Delivery, Financing and Oversight (6 clusters); and Human Resources (2 clusters). The RESYST was comprehensive and well aligned with the Convention. On average, there was a moderately positive correlation between importance and feasibility of the indicators (r=.58) with experts prioritizing the indicators contained in the clusters of the Governance and Leadership domain. Two of the most important indicators arose from the Service Delivery, Financing and Oversight domain and reflect the need to monitor unmet needs and barriers in access to rehabilitation. In total, 59 indicators achieved above average score for importance and comprised the two–tiered priority set of indicators. Conclusion: Concept mapping was successful in generating a shared model that enables a system’s view of the most critical legal, policy and programmatic factors that must be addressed when assessing country efforts to reform, upscale and improve rehabilitation services. The RESYST provides a data driven basis for the development of standardized data collection tools to facilitate comparative analysis of rehabilitation systems.
The Necessity of ASEAN Competition Law: Rethinking
Authors: Silalahi Udin , Parluhutan Dian
Published: January 2018

As outlined in the AEC Blueprint, all ASEAN member states (AMSs) will endeavour to introduce competition policy by 2015. At present 7 (seven) AMSs, namely: Indonesia, Singapore, Malaysia, Thailand, Vietnam, Philippines, Myanmar have the national competition laws to supervise anti-competitive conduct in the domestic market. But the question is what if happened unfair competition between ASEAN member states, due to the agreement or businesses activities by business actors that harm competition? ASEAN has an ASEAN Regional Guidelines on Competition Policy (ARGCP) that developed by ASEAN Experts Group on Competition (AEGC) as framework for member states to develop its own competition law or policy and as a guideline in measuring that directly affect the behaviour of enterprises and the structure of industry and markets. Regional Guideline is just to help AMSs in increasing of awareness of important policy, not to sustain the competition among ASEAN member countries. Until now there is no ASEAN Competition Law and Institution to oversee competition among ASEAN member countries. In this era, ASEAN economic integration it is a certainty that anti-competitive among AMSs will happen.
Legal Policy of Interfaith Marriage in Indonesia
Authors: Hedi Fathol , Anshori Abdul Ghofur , Harun Harun
Published: January 2018

Marriage is not just a bond between men and women, but the inner bond between a man and a woman based on the One and Only God. This research was a philosophical normative, thus the approaches used were philosophical, normative, and historical. Besides, a qualitative-descriptive strategy was used in finding a depth description of the law politics of interfaith marriage regulation in Indonesia based on the the 1974 Marriage Law. The results show that the interfaith marriage is not regulated in the 1974 Marriage Law, because: First, the rejection of the majority of Muslims and the faction in Parliament because the interfaith marriage is against the aqidah (matters of faith) of Islam; Second, the interfaith marriage is contrary to the marriage culture in Indonesia, because marriage contains legal, sociology and religious aspects; Third, the interfaith marriage is contrary to the theological teachings of religions in Indonesia that do not want interfaith marriages, such as Islam, Christianity, Protestantism, Hinduism and Buddhism. Furthermore, the interfaith marriage is inconsistent with the philosophical purposes of marriage in Indonesia where the purpose of marriage forms a happy and eternal family based on the One Supreme God.
Development of a Geomechanical Model for Drilling Deviated Wells through the Zubair Formation in Southern Iraq
Authors: Abbas Ahmed K. , Al-Asadi Yousif M. , Alsaba Mortadha , Flori Ralph E. , Alhussainy Shaban
Published: January 2018

The Zubair Formation is the most prolific reservoir in Iraq, which is comprised of sandstones interbedded with shale sequences. Drilling deviated boreholes in this formation has always been a challenge due to the weak nature of the shale sequence. Historically, over 90% of wellbore problems in the Zubair Formation are due to wellbore instability. These wellbore instability problems, such as hole collapse, tight hole, stuck pipe, and sidetracks results in increasing the nonproductive time (NPT) and well costs. The present study aims to construct a calibrated post-drill 1-D mechanical earth model (MEM) that can be used to conduct a comprehensive geomechanical analysis of the Zubair Formation.

A practical methodology was detailed for (1) constructing the 1-D MEM by using data from several open hole logs and (2) calibrating such a model using all the available data (e.g., observations of wellbore failures, measurements of well testing, laboratory test results of rock mechanical properties, etc.). Three failure criteria (i.e., Mohr-Coulomb, Mogi-Coulomb, and Modified Lade) were used to perform a root cause analysis of borehole breakouts and to address the minimum required mud weight to minimize wellbore instability-related issues for different well trajectories.

The wellbore failure analysis showed that the mud weight, that was used previously, is insufficient to support the rock on the wellbore wall, and it is not appropriately adjusted according to the variation in the wellbore azimuth and inclination. In addition, the heterogeneity of the Zubair Formation and the inappropriate drilling practice have magnified the severity of the drilling problems. The predictions resulting from this study can be used as cost-effective tools when planning for future neighboring deviated wells to create better drilling efficiency by reducing the nonproductive time and well costs.
Novel Modified Rectorite Provides Reliable Rheology and Suspendability for Biodiesel Based Drilling Fluid
Authors: Li Wai , Liu Jishan , Zhao Xionghu , Zhang Jian , Jiang Jiwei , He Tao , Liu Liu , Shen Peiyuan , Zhang Min
Published: January 2018

The use of organophilic clays as additives for providing proper rheological and filtration properties in non-aqueous drilling fluids (NADFs) has long been a topic of study. Currently, most of these clays are based on the modification of bentonite with quaternary ammonium salts. As new NADF systems emerging, novel clay-modification technologies are needed urgently to obtain more effective organophilic clays for specific drilling fluids. This paper introduced a modified rectorite designed for biodiesel-based drilling fluid (BBDF). Through a suspension production technique, rectorite, a clay mineral formed by dioctahedral mica layer and dioctahedral smectite layer with a 1:1 type of layer structure and a peculiar banded structure, was modified by non-ionic surfactants. The swell behavior of the modified rectorite in invert biodiesel emulsion was investigated. Effects of this novel organophilic clay on the electrical stability, rheological parameters and suspendability of biodiesel emulsion were also tested. The results showed that some non-ionic surfactants can be intercalated into the structure of rectorite, altering the wetting characteristic of the clay surface. Compared to traditional organophilic bentonite, modified rectorite has better swell performance in biodiesel emulsion. The abilities of modified rectorite to improve yield point (YP) and low end rheology (e.g., 6 rpm reading) of biodiesel emulsion are also significantly stronger than those of traditional organophilic bentonite, suggesting a higher efficiency of adjusting rheology and suspendability. Combined with appropriate rheological modifiers (RMs), the modified rectorite can provide formulated BBDF a great suspendability, which is evidenced by static barite-sag test. Electrical stability of biodiesel emulsion was also enhanced with the addition of the modified rectorite due to the forming of Pickering emulsion. This novel modified clay is a reliable guarantee of steady properties of BBDF. The origin of its good performance can be attributed to the selection of suitable surfactants and the rational preparation technology. Rectorite is widespread all around the world and there are some rectorite mining areas in various countries although the degree of utilization for this clay is still low at present. In view of the relatively lower price of rectorite compared to bentonite, modified rectorite can be considered as a high-performance, cost-effective viscosifier for BBDF and perhaps, other NADFs.
Retrieval of Intelligent Completions Challenges and Solution
Authors: Kamal Syed Muhammed , Teran Juan M. , M. Adamawi Marwan , Qazi Muhammed Qasim
Published: January 2018

De-completing wells — due to downhole problems related to tubing-casing annulus communication, casing leaks or prior to executing re-entry sidetracks for multilateral wells — is adaily activity in the oilfield business. Conventional completions comprised of downhole production packers and tubing are normally retrieved with no major issues. But this is not the case for intelligent completions, as they include a numberof downhole components that makes its retrieval more challenging, and there was no set procedure or provision in place to retrieve them, in case of failure or encountered downhole problems during the production life of the well.

Since intelligent completion deployments are increasing, the number of intelligent wells to be de-completed will also increase.

This paper presents the case history and experience gained during the de-completion of intelligent completions of different designs; highlights the challenges and difficulties in recovering of multiple packers and flow control valves; and the strategy to achieve full access to the wellbore, to re-establish production and recover assets. This paper will also summarize lessons to achieve successful de-completion of an intelligent well.
Drilling Fluids Automix
Authors: Hestad Vidar , Gulbrandsen Arild
Published: January 2018

Two Schlumberger companies, Cameron and M-I SWACO, joined efforts to provide market with a drilling fluid optimization system to be used during drilling operations. Cameron delivers a complete remote-controlled and automatic drilling fluids mixing system, while M-I SWACO's technology facilitates continuous real-time measurement, analysis and optimization of mud properties. Today mud samples are measured every 6 hours or more frequently, depending on the conditions in the well. The properties are then adjusted for the most part manually, based on a mud engineer's practice.

The Cameron Automix system comprises mechanized equipment and a robot for addition of chemicals into the drilling fluid, and works in concert with the M-I SWACO RheoProfiler instrument, which measures and analyzes drilling fluid properties in real time. Schlumberger (SLB) algorithms, designed to care for the known wellbore situations, automatically create optimal recipes for the chemicals to be mixed into the drilling fluid.

The synergies between M-I SWACO's core competence in fluids and RheoProfiler technology and Cameron's competence in software and mixing equipment, result in a unique method / system of continuous stabilization and control of the wellbore through drilling fluid optimization.

With the focus on a fully autonomous ‘closed-loop’ drilling rig, the spotlight is strongly directed on the drill floor activities and their automation. The main goal of SLB, in terms of automation and closed-loop activities, is to improve the primary well barrier, keep well conditions under control, and rig safe. A combination of each company's strengths, Automix and RheoProfiler can play an essential part in moving the drilling industry towards the same philosophy of fully automated and intelligent systems. The entire drilling operation needs to be viewed as one system, with one organization working towards a common goal, reducing exploration cost without compromising safety. However, there will always be a need for the mud engineer on board.

Less visible in the general hype around automation and more efficient drilling operations, is the importance of optimized properties of the mud in the drilling process. Safety during drilling, better well bore, economy or producing reservoir are just a few of the benefits of the SLB solution.
First Fully Successful Application of a Multistage Acid Fracturing Operation to Stimulate a Carbonate Formation, Resulting in the Implementation in Other Wells in the Mature Bahrah Field, North Kuwait
Authors: Mofti M. , Al-Othman M. , Alboueshi A. , Davis J. , Eid W. , Allam A. , Hamad A. Al , Sadeddin S. , Buhamad A. , Ashkanani M. , Aloun S. , Al-Haddad M. , Al-Mehanna H.
Published: January 2018

Throughout the last few years, oil company strategies have moved toward recovery of the maximum oil in place from mature fields and reservoirs that were previously considered technically challenging. The Mauddud formation in the Bahrah field is a low permeability carbonate formation with moderate to high oil viscosity. Viscosity is between 2 and 7 cp at 170°F, but a 90-cp viscosity at surface conditions is commonly observed once a well is placed on production, creating challenges for a vertically drilled well that could not provide necessary levels of sustainable production. In an attempt to achieve economic continuous production, a 3,000-ft lateral horizontal well was drilled. The lateral length was designed as an optimal solution for such a challenging reservoir to help sustain the production flow. Additionally, a multistage acid fracturing (MSAF) treatment was performed.

This paper discusses the design, execution, and production of the first MSAF treatment performed in the Mauddud reservoir using a cased openhole completion with swell packers and sliding sleeves that were placed in seven stages across the 3,000-ft lateral interval. Post-operation analysis exhibited highly sustained production, creating a shift in oil company plans toward drilling new horizontal wells and applying MSAF treatments to move the Bahrah field into the development phase. Results obtained from this operation were effectively used to help improve production in similar mature formations.

Based on this pilot treatment, a wide-scale field development strategy was planned, and many wells were drilled, completed, and fractured similarly in Bahrah field.
Repair of Surface Casing Failure Allowing Production Restart of Highly Productive Well
Authors: Bourgoin S. , Mendizabal C. Rojas , Tierno S. Santiago , Portillo L. , Barbee G.
Published: January 2018

A strategic well was drilled in 2001 (highly productive well with low CO2 content despite its age). A cellar cleaning campaign was performed on 03/2016, while the well was in production (450,000 sm3/day of gas). The 20" casing was found parted below the Starting Head at the cellar level, with evidence of corrosion. The cut had been buried in sediment for an unknown period and prolonged exposure to water and sediment accumulated in cellar was suspected.

Wellhead movement due to thermal expansion (axial and lateral) was reported during monitoring. Additionally, annulus B, formed by the 13-3/8" casing × 9-5/8" casing annulus was pressured with 16 bars.

The wellhead was found not directly supported by the landing base and axial/torsional force cycles during production/shutdown periods generated fatigue on the 20" casing. This load combination, added to lack of inspections and cleaning on cellar resulted in the failure of 20" casing at surface.

Heavy workover remedial options were studied with prospective high costs and long delays. At the same time a Call for Tenders was launched to find solutions to safely put back well in production at the shortest possible delay. Boots & Coots/Halliburton proposal was selected for engineering and execution. The operation was treated as a Workover (well secured and capped with BOP). Main stages involved: Installation of Downhole plugs, monitor of annular pressures and bleed off operations.Surface installations removal. Cellar Floor and one wall removal (trench excavation).50 cm below cellar excavation to find 20" casing in good conditions. Cut corroded section of 20" casing.Build foundations and rig up Strand-Jack Crane. Cap well with BOP, install tensioning spool system and Tension the inner csg & tbg to 465 kips to get 34 mm displacement and compensate the thermal retraction (Engineering calculations using WellCat™ Software).Replace the 20" corroded section with 2 new half-moon 20" casing sections (welded).Finally release tension on an engineered landing base specially built for purpose.

The objectives were fully achieved through this innovative and multidisciplinary engineering and operational approach. Three months of preparation and engineering were required. The operations were carried out safely (0 incidents) and cost effectively (heavy workover to change wellhead avoided). The well was re-connected and put back in production in April 2017. Production is currently at former levels (430,000 sm3/day peaks-choke not fully open).
Well Control for Drilling with Casing: Theoretical and Experimental Insights into Hydraulic Behavior in Small Annular Clearances
Authors: Meza O. Grijalva , Kamp K. , Asgharzadeh A. , Bello O. , Freifer R. , Oppelt J.
Published: January 2018

The technique of drilling a wellbore by using casing instead of drill pipe (Casing Drilling-CD) is gaining in relevance within the Oil & Gas sector since its implementation in the last decades. This technique, aside from the evident reduction in drilling time and costs observed whenn applied is convenient to minder the effects of certain while-drilling issues as those arising while drilling unstable formations. The focus of concern in this work will be the geometry-related aspects of Casing Drilling influencing not only the drilling operation itself but its particular well control needs as well; this latter will be explained in detail.
New Technique to Evaluate the Performance of Hydraulically Fractured Horizontal Wells
Authors: Abdalla Mohamed , Hassan Amjed , Abdulraheem Abdulazeez , Elkatatny Salaheldin , Mohamed Abdelmjeed
Published: January 2018

The horizontal wells are applied to enhance the production rate by increasing the contact area between the wellbore and reservoir, it has been also used to access the highly heterogeneous and unconventional formations. One horizontal well can produce the same amount of 5 vertical wells with a very competitive cost and operational time. Further improvement for the productivity of horizontal well can be achieved by conducting hydraulic fracture operations, especially for low permeable or unconventional formations. This paper shows a new technique to estimate the performance of hydraulically fractured horizontal wells, without a need for using downhole valves or smart completion.

In the literature, few empirical models have been proposed to evaluate the inflow performance of such wells. However, most of these models assume constant pressure drop in the horizontal section, therefore, significant errors were reported from those models. In this work, a reliable model will be presented to predict the well deliverability for hydraulically fractured horizontal well producing from heterogeneous and anisotropic formation. Different artificial intelligence (AI) methods were investigated to evaluate the well performance using a wide range of reservoir/wellbore conditions. The significant of several parameters on the well productivity were investigated including; permeability ratio (kh/kv), number of fracture stages and the length of horizontal section.

The AI model was developed and validated using more than 300 data sets. Artificial neural network (ANN) model is built to determine the production rate with an acceptable error of 8.4%. The model requires the wellbore configurations and reservoir parameters to quantify the flow rate. No numerical approaches or downhole well completions were involved in this ANN model, which reduce the running time by avoiding such complexity. Moreover, a mathematical relation was extracted from the optimized artificial neural network model. In conclusion, this work would afford an effective tool to determine the performance of complex wells, and reduce the differences between the actual production data and the outputs of commercial well performance software.
Well Integrity Model - Klever & Tamano Collapse
Authors: Brechan Bjorn , Kornberg Even , Sangesland Sigbjorn , Dale Stein Inge
Published: January 2018

Better understanding of collapse resistance of casing and tubing can unlock significant value in support of Asset Life Extension (ALE), support routine Well Integrity assessments in every day work and save significant cost by omitting costly oversized designs. Many operators still use the traditional API collapse model, which were accurate for tubulars produced 50 years ago but now underestimate collapse resistance and predicts typically 80 – 85% of the real collapse pressure. Adding to the excess dimensioning is the standard procedure of applying a safety factor to this prediction.

Early 2000, a joint API/ISO Work Group 2b (WG2b) under the Steering Committee 5 (SC5) for tubular goods reviewed casing and tubing performance property equations. ISO/TR 10400:2007, equivalent to API TR 5C3, presents the results from the extensive testing, and the Klever and Tamano (K&T) model for collapse prediction was found to be most accurate. Building on the test data from WG2b/SC5 group, a model was made for collapse pressure prediction of tubulars - hereafter referred to as the "Ultimate Limit Strength (ULS) model", where the simulation result is a prediction of tubular failure. Its predictive accuracy is calibrated with a complete set of data from 113 actual collapse tests offered by the Drilling Engineering Association (DEA). The ULS model was used to predict collapse strength of 9 5/8 inch 53.5 ppf, P-110 casing, using parameters with probability density functions (PDF) for the relevant type of pipe, e. g., quenched & tempered (Q&T), hot rotary straightened (HRS). The PDFs for each input parameter were obtained by measurements of the 113 samples and compared with the PDFs obtained by the WG2b/SC5 group. Random value generators in a mathematical spreadsheet allowed for Monte Carlo simulations to output 100 000 collapse strength predictions for the 9 5/8 inch casing in question. With confidence level of 97.5%, the basic strength was 9900 psi using PDFs from the DEA data set. Using ensemble PDFs, the basic strength was 9500 psi – 19.5% greater than API's standard rating of 7950 psi.

Performing casing and tubing design, the industry practice is to develop load cases to identify the design limiting loads for the well. Once identified, the pipe selected needs to be investigated for factors reducing the collapse capacity further, e.g. axial / triaxial loads and wall loss from wear and tear. Axial loading is accounted for in the ULS model through the theories of Klever & Tamano. Aspects briefly discussed and not fully incorporated in the prototype ULS model are the linear derating factors considering imposed ovality, casing wear and experimental formulas derived for increased collapse strength of pipe in compression. These were conservatively approximated by polynomial curve fitting of an alternative formulation of yield collapse strength and tried in a version of the prototype model.