bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulating and Predicting the Impacts of Light Rail Transit Systems on Urban Land Use by Using Cellular Automata: A Case Study of Dongguan, China
Authors: Lin Jinyao , Chen Tongli , Han Qiazi
Published: April 2018

The emergence of Light Rail Transit systems (LRTs) could exert considerable impacts on sustainable urban development. It is crucial to predict the potential land use changes since LRTs are being increasingly built throughout the world. While various land use and land cover change (LUCC) models have been developed during the past two decades, the basic assumption for LUCC prediction is the continuation of present trends in land use development. It is therefore unreasonable to predict potential urban land use changes associated with LRTs simply based on earlier trends because the impacts of LRT investment may vary greatly over time. To tackle this challenge, our study aims to share the experiences from previous lines with newly planned lines. Dongguan, whose government decided to build LRTs around 2008, was selected as the study area. First, we assessed the impacts of this city’s first LRT (Line R2) on three urban land use types (i.e., industrial development, commercial and residential development, and rural development) at different periods. The results indicate that Line R2 exerted a negative impact on industrial development and rural development, but a positive impact on commercial and residential development during the planning stage of this line. Second, such spatial impacts (the consequent land use changes) during this stage were simulated by using artificial neural network cellular automata. More importantly, we further predicted the potential impacts of Line R1, which is assumed to be a newly planned line, based on the above calibrated model and a traditional method respectively. The comparisons between them demonstrate the effectiveness of our method, which can easily take advantage of the experiences from other LRTs. The proposed method is expected to provide technical support for sustainable urban and transportation planning.
Hybrid Electric Vehicles: Some Theoretical Considerations on Consumption Behaviour
Authors: Carlucci Fabio , Cirà Andrea , Lanza Giuseppe
Published: April 2018

Solving the problem of the lack of environmental sustainability in transport activities requires the involvement of new technologies, particularly in populated cities where mobility activities play a major role in generating externalities. The move from cars powered by conventional internal combustion engines to cars powered by alternative energies can make an important contribution to reducing emissions and achieving a more sustainable transport system. Unfortunately, green car market development still remains uncertain because of the higher production costs of batteries and engines. In this context, surprisingly little attention has been devoted to analysing the economic factors affecting consumers’ behaviour in the choice of hybrid electric vehicles. To fill this gap, the diffusion process of hybrid technology as well as intrinsic and extrinsic motivations and the crowding-out effect on consumers’ purchasing decisions are taken under consideration. Finally, some policy recommendations are provided.
The Effects of Diversification Activities on the Technical Efficiency of Organic Farms in Switzerland, Austria, and Southern Germany
Authors: Lakner Sebastian , Kirchweger Stefan , Hoop Daniel , Brümmer Bernhard , Kantelhardt Jochen
Published: April 2018

The diversification of farms can be a result of multifunctional farming, however, in some cases at the cost of lower farm efficiency. In our paper we investigate the influence of para-agricultural diversification on productivity and the technical efficiency of organic farms in Austria, Switzerland, and Southern Germany. We show the benefits and drawbacks of diversification for organic farms, which go beyond the core agricultural production (para-agriculture). We do this by estimating a Stochastic Frontier (SF) combined with a metafrontier model. The data-set consists of bookkeeping data with 1704 observations in the years 2003 to 2005. Para-agricultural diversification activities have a significant effect on both productivity and technical efficiency of organic farms: The farm output in Austria and Switzerland is positively influenced by diversification, whereas we observe a rather small effect in Southern Germany. On the other hand, diversification can reduce farms’ technical efficiency, as it is the case in Switzerland and Germany. Furthermore, our study confirms previous results that agricultural subsidies significantly influence the technical efficiency of organic farms. We also show expected changes of input use driven by increased farm diversification.
Safety Assessment Model for Dangerous Goods Transport by Air Carrier
Authors: Zhao Hongli , Zhang Ning , Guan Yu
Published: April 2018

The safety of dangerous goods transport by air is directly related to human health and environmental pollution. This paper investigates a model to evaluate the safety performance of the transport of dangerous goods by air carriers. Based on a literature review, international regulations related to dangerous goods air transportation, and expert opinions, this paper identifies an assessment factor system with five drivers: organization/regulations, equipment/facilities, operations, emergency, and training. A hybrid evaluation method of a joint analytical hierarchy process and entropy weight is used to determine the importance of each factor and driver. The results suggest that the regulation of dangerous goods acceptance, sufficient equipment/facilities, and the condition of the equipment/facilities are the most important factors affecting the safety performance of dangerous goods transportation by air. An empirical study reveals that the proposed model is stable and reliable; thus, the model can guide resource allocation for air carriers to improve safety management of dangerous goods transportation.
Multi-Source Stego Detection with Low-Dimensional Textural Feature and Clustering Ensembles
Authors: Li Fengyong , Wu Kui , Zhang Xinpeng , Lei Jingsheng , Wen Mi
Published: April 2018

This work tackles a recent challenge in digital image processing: how to identify the steganographic images from a steganographer, who is unknown among multiple innocent actors. The method does not need a large number of samples to train classification model, and thus it is significantly different from the traditional steganalysis. The proposed scheme consists of textural features and clustering ensembles. Local ternary patterns (LTP) are employed to design low-dimensional textural features which are considered to be more sensitive to steganographic changes in texture regions of image. Furthermore, we use the extracted low-dimensional textural features to train a number of hierarchical clustering results, which are integrated as an ensemble based on the majority voting strategy. Finally, the ensemble is used to make optimal decision for suspected image. Extensive experiments show that the proposed scheme is effective and efficient and outperforms the state-of-the-art steganalysis methods with an average gain from 4 % to 6 % .
piRNA Profiling of Dengue Virus Type 2-Infected Asian Tiger Mosquito and Midgut Tissues
Authors: Wang Yanhai , Jin Binbin , Liu Peiwen , Li Jing , Chen Xiaoguang , Gu Jinbao
Published: April 2018

The Asian tiger mosquito, Aedes albopictus, is a competent vector for the majority of arboviruses. The mosquito innate immune response is a primary determinant for arthropod-borne virus transmission, and the midgut is the first barrier to pathogen transmission. Mosquito antiviral immunity is primarily mediated by the small interfering RNA pathway. However, the roles that the P-element induced wimpy testis (PIWI)-interacting RNA (piRNA) pathway play in antiviral immunity in Ae. albopictus and its midgut still need further exploration. This study aimed to explore the profiles of both viral-derived and host-originated piRNAs in the whole body and midgut infected with Dengue virus 2 (DENV-2) in Ae. albopictus, and to elucidate gene expression profile differences of the PIWI protein family between adult females and their midguts. A deep sequencing-based method was used to identify and analyze small non-coding RNAs, especially the piRNA profiles in DENV-2-infected Ae. albopictus and its midgut. The top-ranked, differentially-expressed piRNAs were further validated using Stem-loop qRT-PCR. Bioinformatics analyses and reverse-transcription PCR (RT-PCR) methods were used to detect PIWI protein family members, and their expression profiles. DENV-2 derived piRNAs (vpiRNA, 24–30 nts) were observed in both infected Ae. albopictus and its midgut; however, only vpiRNA in the whole-body library had a weak preference for adenine at position 10 (10A) in the sense molecules as a feature of secondary piRNA. These vpiRNAs were not equally distributed, instead they were derived from a few specific regions of the genome, especially several hot spots, and displayed an obvious positive strand bias. We refer to the differentially expressed host piRNAs after DENV infection as virus-induced host endogenous piRNAs (vepiRNAs). However, we found that vepiRNAs were abundant in mosquito whole-body tissue, but deficient in the midgut. A total of eleven PIWI family genes were identified in Ae. albopictus; however, only AalPiwi5–7 and AalAgo3(1–2) were readily detected in the midgut. The characteristics of piRNAs in DENV-2-infected Ae. albopictus adult females were similar to those previously described for flavivirus infections but were not observed in the midgut. The reduced levels of vepiRNAs and incomplete expression of PIWI pathway genes in midgut samples from DENV-2-infected Ae. albopictus suggests that viral regulation of host piRNAs may not be an important factor in the midgut.
Seasonal and Interannual Variability in Coastal Circulations in the Northern South China Sea
Authors: Liu Jin , Dai Juanjuan , Xu Dongfeng , Wang Jun , Yuan Yeping
Published: April 2018

Seasonal cycle and interannual variability in coastal circulations in the northern South China Sea (NSCS) are investigated using satellite altimeter data from March 1993 to September 2016. Altimeter-derived velocity anomalies are in good agreement with acoustic Doppler current profilers (ADCP) observations at an adjacent location. Along-shelf volume transport anomalies in the NSCS indicate northeastward transports from mid-spring to summer and southwestward transports from mid-autumn to winter, which are consistent with previous studies in this region. According to convergence and divergence in the target control volumes, cross-shelf volume transports are estimated as the differences between two neighboring along-shelf volume transport anomalies, with the assumption that long-term mean along-shelf volume transports at each cross-sections are identical. The results show onshore transports in mid-autumn and offshore transports in early summer. The comparison between altimeter-derived and ADCP-estimated cross-shelf volume transports is encouraging, especially when the region has relatively low mesoscale activities and a low freshwater input. Reconstructed cross-shelf volume transports through multiple linear regression reveal that seasonal harmonics is the primary force in driving cross-shelf volume transports in the NSCS, while wind and El Niño have secondary effects on controlling cross-shelf volume transports in different regions. The present study helps to quantify the long-term coastal circulations, especially cross-shelf volume transports, based on altimeter data, which has important implications on the dynamics in coastal regions where observational data is limited.
Individual Local Farmers’ Perceptions of Environmental Change in Tanzania
Authors: Röschel Lina , Graef Frieder , Dietrich Ottfried , Schäfer Meike Pendo , Haase Dagmar
Published: April 2018

Climatic and environmental changes are expected to affect in particular those regions where the economy is primarily based on the agricultural sector and where the dependency on water availability is high. This study examines how smallholder farmers in rural Tanzania perceived climatic and environmental changes over the past 20 years and the resulting effects on water availability and food security. The study is based on a household survey of 899 farmers in a semi-arid and a sub-humid region in Tanzania. It was found that (a) significant differences in perceptions of the environment by farmers can be attributed to agro-climatic location, while the distance to a water source has less impact on individual perception; (b) differently perceived changes affect individual water availability and food security; and (c) the farm level adaptation methods applied are linked to vulnerability to changes and the household dependence on the immediate environment. The authors conclude that the specific environmental surroundings paired with socio-economic factors can severely compound the negative effects of water scarcity on rural farmers.
Bayesian Inference on the Radio-quietness of Gamma-ray Pulsars
Authors: Yu Hoi-Fung , Hui Chung Yue , Kong Albert K. H. , Takata Jumpei
Published: April 2018

For the first time we demonstrate using a robust Bayesian approach to analyze the populations of radio-quiet (RQ) and radio-loud (RL) gamma-ray pulsars. We quantify their differences and obtain their distributions of the radio-cone opening half-angle δ and the magnetic inclination angle α by Bayesian inference. In contrast to the conventional frequentist point estimations that might be non-representative when the distribution is highly skewed or multi-modal, which is often the case when data points are scarce, Bayesian statistics displays the complete posterior distribution that the uncertainties can be readily obtained regardless of the skewness and modality. We found that the spin period, the magnetic field strength at the light cylinder, the spin-down power, the gamma-ray-to-X-ray flux ratio, and the spectral curvature significance of the two groups of pulsars exhibit significant differences at the 99% level. Using Bayesian inference, we are able to infer the values and uncertainties of δ and α from the distribution of RQ and RL pulsars. We found that δ is between 10° and 35° and the distribution of α is skewed toward large values.
Study of Azole - Resistant and Cyp51a Gene in Aspergillus Fumigatus
Authors: Zarrin Majid , Faramarzi Sama
Published: April 2018

AIM: The main goal of the present study was to find azole-resistant and molecular analysis of cyp51A gene in Aspergillus fumigatus.MATERIALS AND METHODS: Fifty-eight A. fumigatus strains including environmental, clinical and reference isolates were assessed in this investigation. Azole susceptibility testing for itraconazole and voriconazole was carried out for A. fumigatus isolates. PCR was performed based on cyp51A gene sequence for all isolates.RESULTS: Susceptibility testing verified the minimum inhibitory concentrations (MICs) for itraconazole (0.125 to 2 µg/ml) and voriconazole (0.125 to 4 µg/ml). Nine (15.5%) A. fumigatus isolates were resistant to voriconazole with MIC 4 µg/ml. A 1500 bp DNA fragment was amplified using cyp51A gene for all tested Aspergillus isolates. The sequences of the fragments showed 99% identity with A. fumigatus cyp51A gene in the GenBank. No point mutation was found at cyp51A gene codons.CONCLUSION: In the current study, we detected the voriconazile resistant in A. fumigatus isolates. Susceptibility tests should be considered in patients who infected by A. fumigatus.
A revision of Xylopia L. (Annonaceae): the species of Tropical Africa
Authors: Johnson David M. , Murray Nancy A.
Published: April 2018

A revision of the 45 species of the pantropical genusXylopiain Tropical Africa includes descriptions of six new species and a new section of the genus. The fruits and seeds ofXylopiashow specializations that promote vertebrate dispersal, primarily by hornbills and monkeys. Over half of the African species have an Area of Occupancy (AOO) less than 80 km2, suggesting that they are in need of protection. African species are classified into five sections. Section Neoxylopia , with four species, is centered in the Guineo-Congolian Region and includesX.globosasp. nov.Section Ancistropetala, with three species, occurs in the same region. Both of these sections are endemic to Africa. Section Xylopia, which extends to Madagascar and the American tropics, has only a single species in Africa,X.aethiopica. The three species of section Verdcourtiasect. nov.are restricted to the East African coast and Madagascar. The largest number of African species, (34) belong to section Stenoxylopia, in which the seeds lack the arils found in the other sections and instead have a fleshy sarcotesta. Section Stenoxylopia is divided into two informal groups, one centered in eastern and southern Africa (X.odoratissimagroup) and the other centered in the wetter forests of western and central Africa (X.acutifloragroup). Five new species are described in section Stenoxylopia:Xylopianiloticasp. nov.from Sudan, South Sudan, and Uganda,Xylopiacalvasp. nov.from Nigeria and Cameroon, which is allied toX.phloiodora, andXylopiamonticolasp. nov.from Nigeria and Cameroon,X.pirataesp. nov.from Ivory Coast and Ghana, andX.unguiculatasp. nov.from Gabon. The latter three species are segregates of the formerXylopiaacutifloras. l. One new combination is made at the species level,X.shirensiscomb. nov.Keys, descriptions, illustrations, distribution maps, and an index to numbered collections document diversity and assist with species identification. The nameUnonaoliverianaBaill. was found to pre-date the nameUnonalepidotaOliv., requiring the combinationMeiocarpidiumoliverianumcomb. nov.
Data Security and Privacy Assurance Considerations in Cloud Computing for Health Insurance Providers
Authors: Tamunobarafiri Amavey , Aghili Shaun , Butakov Sergey
Published: April 2018

Cloud computing has been massively adopted in healthcare, where it attracts economic, operational, and functional advantages beneficial to insurance providers. However, according to Identity Theft Resource Centre, over twenty-five percent of data breaches in the US targeted healthcare. The HIPAA Journal reported an increase in healthcare data breaches in the US in 2016, exposing over 16 million health records. The growing incidents of cyberattacks in healthcare are compelling insurance providers to implement mitigating controls. Addressing data security and privacy issues before cloud adoption protects from monetary and reputation losses. This article provides an assessment tool for health insurance providers when adopting cloud vendor solutions. The final deliverable is a proposed framework derived from prominent cloud computing and governance sources, such as the Cloud Security Alliance, Cloud Control Matrix (CSA, CCM) v 3.0.1 and COBIT 5 Cloud Assurance.
Digital Divide and Citizen Use of E-Government in China's Municipalities
Authors: Ma Liang
Published: April 2018

By using the 2014 randomly sampling survey of 36 major cities in China, the author empirically examines the status and predictors of e-government use by citizens. The author finds that nearly one third of the respondents accessed online services of city government websites, and the sampled cities vary substantially in the percentage of e-government uptake. The results show that e-government use is primarily driven by citizen trust in government, age, education, and income, whereas political efficacy, gender, nationality, household types, and occupations are not significant. There is a notable digital divide in relatively disadvantageous groups, and the government should pay particular attention to boost e-government use among these individuals.
Developing Smart Cities in China
Authors: Yu Wenxuan , Xu Chengwei
Published: April 2018

This article describes how being pushed and pulled by a variety of external and internal factors, the Chinese government had begun to adopt and implement its smart city initiatives. Despite the strong financial and institutional supports from the central government, the performances of smart city initiatives significantly vary across pilot sites. Considering smart city initiatives as government innovation and drawing on the government innovation diffusion theories, an explanatory model has been developed to examine their variance and test it with a cross-sectional dataset using multiple regression methods. It was found that although environmental pollution was a key driver for the development of smart city in China, such environmental pollution like air pollution in particular had a curvilinear relationship (bell-shaped) with smart city development. In addition, smart cities initiatives in China were driven not only by technical rationalities but also political rationalities. Political supports from local ruling party sectaries made a difference.
Quantitative Prediction of Rat Hepatotoxicity by Molecular Structure
Authors: Papa Ester , Sangion Alessandro , Taboureau Olivier , Gramatica Paola
Published: April 2018

In this article, Quantitative Structure Activity Relationships (QSAR) were generated to link the structure of over 120 heterogeneous drugs to rat hepatotoxicity. Existing studies, performed on the same data set, could not highlight relevant structure-activity relationships, and suggested models for the prediction of hepatotoxicity based on genomic data. Binary activity responses were used for the development of classification QSARs using theoretical molecular descriptors calculated with the software PaDEL-Descriptor. A statistically powerful QSAR based on six descriptors was generated by using k-Nearest Neighbour (k-NN) method and by applying the Genetic Algorithm (GA) as variable selection procedure. The new k-NN QSAR outperforms published models by providing better accuracy and less false negatives. This model is a valid alternative to approaches based on genomic descriptors, which cannot be used in virtual screening of new compounds (pre- or post-synthesis) without experimental data.
The Bank's Regional Director's Emotional Bias and the Bank's Performance
Authors: Souissi Yasmine , Azouzi Mohamed Ali , Jarboui Anis
Published: April 2018

This article tries to study the impact of the bank regional manager's emotional bias on the performance of Tunisian banks. This is by taking into account the mediating role of the decentralization of decision-making rights. For this purpose, an empirical study was carried out using a questionnaire as a data collection method and using a sample of 100 regionals directors of Tunisian banks. This article reflects an original approach, as it highlights the role of behavioral aspects in explaining the level of performance within the framework of the organizational architecture theory. In fact, the results show that the behavioral dimension is a central dimension in the organizational architecture.
A Roadmap for Adopting a Digital Lifecycle Approach to Offshore Oil and Gas Production
Authors: Grange Elgonda La
Published: April 2018

In recent years, there has been a great deal of discussion surrounding the opportunities presented by digitalization in offshore oil and gas. However, despite the increased attention, operators have received little direction from digital solutions providers on how to fully capitalize on its benefits. This paper will aim to change that by providing a blueprint for adopting a digital lifecycle approach to offshore oil and gas production.

The approach presented in this paper, which we will refer to as Topsides 4.0 for ease of reference, is an integrated digital lifecycle approach to rotating equipment and electrical and automation systems, underpinned by secure communications. The approach is designed to enable digital design and manufacturing, virtual testing and commissioning, and delivery of an intelligent "digital twin" of a topsides facility. The digital twin is a virtual replica that mirrors the physical facility in near real-time, thus providing a number of advantages to offshore O&G producers, including the capability to run virtual what-if scenarios on the asset and better understand how process, equipment, and maintenance would be impacted by different operating conditions.

Additionally, the paper will address challenges and concerns associated with digitalization in offshore O&G production, such as cybersecurity. It will also outline expected cost and schedule savings that topsides operators can achieve by embracing a fully digitalized approach, some of which include 3 – 9 month reduction in cycle times, $10 - $15 million reduction in CAPEX, and $100 million reduction in OPEX over a 10-year period.
Elimination of Fresh Water Use for Chemical Cleaning in Sulfate Removal Units SRU
Authors: Moreira Alexandre M. B. , Lage Gustavo Garios , Tendillo Manuel G. S. , Zhang Xingpeng , Rodrigues Danielle , Pessoa Fábio
Published: April 2018

Water has become more and more a scarce resource and its use rationalization has been a challenge in its several applications. Its status has become even more critical for some platforms and/or oil exploration ships (FPSO => Floating Production Storage and Offloading), that have fresh water (drinkable water) production stations via reverse osmosis and or desalters with limited flows to supply all routine demand and in emergency cases, and it may even be necessary to purchase fresh water from third parties, by means of towing vessel with extremely high unit cost (continent catchment). Thus, we will present in this paper the achievement reached by using a small permeated water volume in SRU (Sulfate Removal Unit), which water, has low sulfate content and is used for injection and in CIPs (Clean In Place) cleaning system, which stands for a large drinkable water consumption within the platform.

The research to be described in this technical document, concerning the permeated water use in SRU to use in CIP solutions, will show the achievement reached in a platform in Brazil, after 2.5 years of research in our Singapore Advance Research Center, using a pilot plant.
BC10 Mudline Pump - A Cost Saving Solution for Brownfields
Authors: Liney D. J. , Bekker M. A. , Broderick R. J. , Cardoso E. W. , Fletcher N. , Bourne M.
Published: April 2018

The Parque das Conchas (BC10) field offshore Brazil, operated by Shell and owned together with ONGC and QPI, has challenging reservoir conditions. Several subsea fields with viscosities ranging from 1 to 900 cP and gas volume fractions between 5% and 70% require subsea boosting to lift production fluids to the FPSO facility. Since first oil in 2009, a unique method of subsea separation and boosting has been deployed on BC-10, utilizing vertical caisson separators with Electrical Submersible Pumps (ESP's) to pump well fluids from up to 2000m water depth to the FPSO facility. Maintenance of the ESP assemblies requires an intervention using a MODU (Mobile Offshore Drilling Unit).

Shell pursued an alternative subsea boosting solution using Mudline Pump (MLP) technology, with the objective to reduce field Opex and increase redundancy. The MLP was conceived as a retrofit module, which was to be fully compatible with the existing infrastructure. This includes using existing variable frequency drives, high voltage umbilicals, subsea mechanical interfaces, controls, hydraulics, and chemical injection. Despite the prior development of a 3 MW (megawatt) MudLine Pump (MK1), the specifics of the BC10 application required further development and qualification. The design pressure was increased from 5,000 psi to 7,500 psi, which required requalification of motor and barrier fluid circuit components. Additionally, the challenging multiphase flow conditions led to the development of an innovative control strategy to maximise the production window, whilst ensuring safe operating conditions for the pump within the existing system constraints.
Expand the Use of Open Wireless Gas Detection Systems for Life Safety and Asset Integrity
Authors: Yeo Julian , Chin Wil
Published: April 2018

As companies struggle to improve the health and safety of the workforce in heavy industrial process industries, it is clear that current solutions demand the flexibility and the fast deployment that an open WirelessHART gas detection system can provide.

Untethering toxic and combustible gas detection systems provide:

Additional coverage - identifies dangerous workforce environments for fast mitigation and improve life safety

Measurements for predictive maintenance program for equipment such as pumps, valves, and tanks

Use of gas detection for identifying leaks in difficult to measure infrastructure such as insulated piping to ensure asset integrity

WirelessHART standard IEC 62591

ISA-TR84.00.07-2010 Technical Report, Guidance for Application of Wireless Sensor Technology to Non-SIS Independent Protection Layers

ISA-TR84.00.08-2017-Technical Report, Guidance on the Evaluation of Fire, Combustible Gas and Toxic Gas System Effectiveness

Deployment in days in lieu of weeks

Reduction in wiring costs

Leaks vs time to detect leaks

Long term performance

Best Practices for deploying wireless gas detection systems
High Speed Telemetry on Wired Drill Pipe, History, and Impact on Drilling Process
Authors: Foster Robert , Macmillan Robin
Published: April 2018

This paper discusses the history and impact of using high-speed telemetry and wired drill pipe on the drilling process. Efficiency gains, well placement advantages, campaign cost reductions, automation improvements, as well as what other operational efficiencies high-speed telemetry can enable.
Improved Operation of Subsea Boosting Systems through Advanced Condition Monitoring and Data Analytics
Authors: Johnsrud Per Christian , Tømmerberg Kyrre , Haaverstad Marius
Published: April 2018

In the current oil and gas market, operators are seeking cost-effective and reliable ways to maximize production from existing infrastructures and to improve economics for greenfield applications. Subsea boosting is a technology enabling economically viable subsea tie-backs, life extension of mature fields and increased profitability of new projects. This paper will show how advanced condition monitoring technology can improve operation of boosting systems, thus making this technology more attractive for field operators.

In recent years, new sensor technologies have been qualified for subsea use and new platforms for handling large quantities of data have been developed. Aker Solutions has combined these technologies in the development of a novel advanced condition monitoring system for subsea boosting applications. Through use of sensor technology and an integrated software and data analytics platform, it is now possible to operate the pump more efficiently. Increasing the reliability of the boosting system by introducing predictive maintenance planning is a key element in reducing the OPEX and improving the operation of the field.

Through execution of an extensive testing campaign in a full-scale multiphase test loop, Aker Solutions has been looking at a number of operating conditions, with varying mixtures of water and gas to demonstrate the performance of this new technology. During the testing, new usage of proximity probes and sensor technologies demonstrated the effectiveness of the system for real-time operation management.

This paper outlines the architecture of the system and presents how the hardware improvements, combined with the latest digitalization technologies, can extend the operating envelope of the system and improve availability.
Renewable Generated Energy for Subsea Power Infrastructure
Authors: Knox Richard , Buck Elaine
Published: April 2018

The O&G industry and renewables industry are integrating more and more through the use of energy conversion systems to cut costs. This paper describes the testing and applications of a renewable generated power source.
The Big Journey of a Giant: The Campos Basin's History
Authors: Batalha M. , Cunha V.
Published: April 2018

With more than 100 thousand square kilometers and representing about 58% of Brazil's oil and gas daily production in 2016, Campos Basin has proved its gigantism by producing 12 billion barrels of oil equivalent since 1977, extracted from the various concessions, like the giant fields of Marlim, Roncador and Jubarte. Comprising fifty-three production units, 711 wells and 14.8 kilometers of subsea pipelines, Campos Basin can be considered one of the largest offshore oil and gas complex operated by a single company in the world. In this context, considering the relevance of this oil province, this paper aims to present the journey of Campos Basin, summarizing the main challenges overcome in the last 40 years, the technologies developed, the strategies applied and the results obtained.
Optimized Field Development through Integrating Field Network with Dynamic Reservoir model
Authors: Hatvik Mahanaz , Nørgård Jens Petter , Berg Kjartan , Vannes Knut , Irmann-Jacobsen Tine Bauck , Cantero Alberto Diaz
Published: April 2018

The world's average oil recovery factor is estimated to be 35%. Increased oil and gas recovery will depend on the availability and utilization of appropriate technology as well as efficient reservoir management and economic strategies. This creates the need for efficiently scanning and evaluating various field architectures during the field development phase, with respect to installed cost, operability and hydrocarbon recovery. A major step towards achieving this improvement is to couple the reservoir performance with the production network.

The objective of this paper is to describe an efficient methodology for coupling one or several dynamic reservoir models with the production network model. This enables effective comparison between different field development concepts including various applications of subsea processing.

To investigate this integrated approach, a real case study has been performed on the Alta and Gotha discoveries operated by Lundin in the Barents Sea.
Numerical Study of Vortex Induced Motion and Vibrations on Risers and Tension Leg Platform for Malikai
Authors: Gupta J. K. , Bhat S. , Yang T. K.
Published: April 2018

The operating environment for the Malikai project is strong and persistent current with speed up to 2 m/s for even a return period of 50 years. This could lead to vortex induced vibration (VIV) of the risers and vortex induced motion (VIM) of the floating systems such as Tension Leg Platform (TLP) or Tender Assisted Drilling (TAD) vessel. The VIV and VIM could affect the riser and mooring system strength and subsequent failure. This could lead to unplanned production deferment and riser maintenance. Therefore, the current study investigated the VIV and VIM phenomenon for Malikai riser and floating system respectively.

The Malikai project used U shaped AIMS fairing to suppress VIV of the risers. These fairings have low drag, provide operational advantage and faster installation compared to traditional VIV suppression methods. Computational Fluid Dynamics (CFD) simulations were performed for the fairing and riser system and confirmed low drag coefficient (0.4) in Malikai environment. Experiments verified it further.

The second part of the study was focussed on investigating VIM of TLP and TAD. The CFD simulations were first carried out to validate the motion of TLP at the lab-scale and established a methodology. The established methods were then used to predict VIM for Malikai TLP and combined motion of TLP-TAD. The drag and lift coefficient for the lab scale TLP at reduced velocity of 10 and heading of 22.5° was 1.33 and 0.13 respectively. The nominal surge, sway and yaw amplitude at this condition was 0.05, 0.12, and 1.8 respectively. These predictions were in well agreement with the experimental data obtained from the University Technology Malaysia (UTM). The sway and yaw frequencies were twice of surge indicating VIM. The motion amplitudes for the Malikai TLP were smaller than the lab scale experimental data at reduced velocity of 5. This could be attributed to difference in Reynolds number and tendon arrangement. There was no evident dominating frequency of motion. It was more of a flow induced motion. The drag and lift coefficients for TLP/TAD at heading of 0° was 1.1/0.28 and 0.014/.001 respectively. The drag and lift coefficients are lower for TAD as it is in the wake of TLP (lower currents around TAD). The motion amplitude for TAD were higher than TLP due to more fluctuations in the drag and lift forces. This could be attributed to TAD having only two pontoons.

The motion amplitudes were overall small for all the cases and could be due smaller submersed height of columns above the pontoons. The motion and drag predictions can be directly used in the design of hull, riser and mooring line systems and can be further integrated with structural analysis to obtain the fatigue life. This was an attempt to capture the VIM and has indicated promising results. An exhaustive validation can aid in standardization of CFD methods and make it a potential tool to predict VIM. Accurate predictions can help in lowering and building confidence in design parameters.
Shearography Inspection to Assess the Structural Integrity of Composite Repairs in Metallic Piping
Authors: Soares Sergio Damasceno , Fampa Ana Lucia , Albertazzi Armando , Fantin Analucia V. , Willemann Daniel P. , Benedet Mauro E. , Silva Fábio A.
Published: April 2018

Metallic pipes installed at top side offshore platforms may show corrosion damage. The corrosive process can be external or internal. One of the forms for mitigation consists in installation of composite repair to recompose the structural integrity of the corroded pipe segment. These kinds of repairs are normalized and considered temporary. After the designed time the repairs must be removed. To bypass the inconvenience of repair removing and production losses associated with the replacement of the corroded area, several projects are running to develop methods to ensure the integrity of the repair and the maintenance of the integrity of the piping. This article presents the development of a shearography system for integrity assessment of composite repairs. This system was developed in conjunction with UFSC. Several laboratory tests performed at real piping systems were done to develop: optomechanical and electronic systems, software and procedure to data acquisition. After laboratory tests, several field tests were performed at offshore and onshore situations to defined the final methodology to be used at real situations. Among the tests performed during development can be cited a campaign held in the PRCI. The technology was field proved at Campos Basin platform and shows that shearography inspection could help Integrity Management groups to keep the installation running in a safety conditions. Auxiliary systems derivatives were tested in similar situations in the inspection of structural composite repairs on hulls of FPSO. It was concluded that shearographic inspection is suitable to assessing the integrity of composite repairs on offshore piping. The next step will be hired this type of service in a regular basis.
Overview of DeepStar Project to Demonstrate the Use of API 17 TR8 - Verification and Validation
Authors: Peters Daniel T. , Gomes Joseph V. , Pham Man , Tipple Chris
Published: April 2018

Structural Integrity Associates (SIA) will share some of the impactful collaborative efforts completed within the DeepStar® Global Deepwater Technology Development Program, as part of DeepStar® 12302 20 ksi Systems project, leading to the development of industry standards and being used as a guideline for deployment with API 17 TR 8 procedure. Additionally, SIA will share the status of the next phase of the validation portion of the project being undertaken.

Subsea equipment with working pressures of 20 ksi and above has been in discussion for several years and is gaining traction with various operators. The purpose of this project is to demonstrate the use of the various design methods discussed in API 17 TR8 [8,9] considering a 5 inch 20 ksi tee assembly, through both verification and validation.

The exercise will provide an example analysis that applies independent usage of API 17 TR8 [8,9]. The process will also allow current 20 ksi contributors and operators to comment on the scope of work in both the verification analysis and validation testing protocol. This will help put into practice the use of API 17 TR8 [8,9] document and provide an independent example of its use.

Structural Integrity Associates, Inc. (SIA) performed a verification assessment for DeepStar using API 17 TR8 [8,9] and the referenced industry standards described therein. This project included (1) Generation of Functional Specification, (2) generation of an example Failure Mode, Effects, and Criticality Analysis (FMECA), (3) design verification, (4) development of a validation protocol, (5) investigation of hydrostatic test effects, (6) fatigue monitoring, (7) investigation of cladding effects, (8) extreme and survival limits, and (9) a comparison of design and total life. After the successful completion of the first phase verification assessment, the current second phase of validation testing includes (1) material characterization, (2) testing of the components for validation of the finite element models for shakedown, (3) testing to validate the models used in the Load Resistance Factor Design (LRFD) for the global criteria.

This paper will provide an overview of the verification assessment performed, an overview of key findings from that report, and validation testing currently being undertaken. Additionally, several areas where official interpretations were requested from ASME to clarify its Codes and Standards will be reviewed.
Wellbore Cool Down Simplifies Using Dissolvable Materials
Authors: Fripp Michael , Walton Zachary
Published: April 2018

Dissolvable materials are enabling a revolution in the completion and stimulation of wellbores. Effective design of dissolvable fracturing tools, however, needs to account for the substantial cooling effect that arises during pump down and stimulation. The degradation process, degradation time, and material properties change because of the wellbore cool down.

A wellbore cools when fluids are injected into the formation. Temperature profiles are measured with fiber-optic cable and are simulated with numerical models. Both measured and modeled results show that downhole temperatures can be cooled to near surface temperatures. This temperature data is combined with experimental dissolution behavior to show that different dissolution behavior occurs during pump down, setting, wellbore stimulation, and wellbore temperature recovery.

The actual temperature that fracturing tools will experience during their useable life depends on wellbore cool down and can be much less than the static formation temperature. All dissolvable materials have dissolution rates and material properties that are temperature dependent. Some dissolvable plastics will not degrade at lower temperatures. Measured and modeled cool down from hydraulic fracturing are used to show the temperature profile during different operational stages. The greatest temperature cool down occurs while the dissolvable fracturing tool is isolating a zone during the fracture treatment. This temperature cool down also occurs during the only time of the operation in which the fracturing tools are required to maintain a significant differential pressure. The temperature cool-down effect becomes more significant as more zones are fractured and more fluid is injected into the formation. Dissolvable fracturing tools should be designed for the temperature experienced during wellbore cool down rather than the static formation temperature.

Both field data and numerical modeling show that a dynamic temperature estimation is more accurate than static bottomhole temperature (BHT) at predicting the temperature experienced by dissolvable fracturing tools. The cool down of the wellbore is an important design parameter for the materials and construction of dissolvable tools.
Functional Design Specification FDS for MPD Equipment Installation on Deepwater Drillships
Authors: Patil Harshad , Deshpande Kedar , Dietrich Earl , Arnone Maurizio
Published: April 2018

Defining the specification and moreover the limitations of Managed Pressure Drilling (MPD) equipment installations on Mobile Offshore Drilling Units (MODU’s) could be challenging from a functionality stand point. These challenges mainly arise from a wide range of functional or drilling parameters that these permanent or semi-permanent MPD installations are exposed to. With the ever increasing demand of using MPD, many of the existing and new built MODU’s are getting furnished with MPD equipment. Since the increase in demand of MPD equipment for the offshore market is attributed to the advantages that the MPD systems exhibit, typically for drilling wells that demonstrate narrow drilling margins, the MPD system significantly assist in managing bottomhole pressures, especially to mitigate ballooning, and to manage losses / kicks. Due to the potential exposure of the MPD installation to extreme environments, and to ensure proper utilization of these MPD systems within its design limits, it is necessary to define the Functional Design Specification (FDS) for the MPD equipment installed on MODU’s.

The FDS consists of four major calculation categories for the MPD equipment installations. These are, "surface line frictional pressure loss calculation", the "PRV sizing calculation", the "Riser degassing with MPD equipment as a function of MGS liquid and gas handling capacity" and lastly the "erosion calculation" of the piping that is installed as part of the MPD equipment on MODU’s. The development, methodology and approach of specific calculations that were performed to estimate the functional design specification, encompassing these four categories are illustrated in this paper.

The paper describes the method utilized to estimate friction loss through MPD surface lines based on specific calculations that estimate friction factors as a function of mud rheological properties, pipe geometry, length etc. The results obtained from the developed program to estimate frictional pressure loss in surface lines, were calibrated using fingerprinting data obtained from earlier installations on similar Drillships. Next, the FDS calculation uses the MGS (Mud gas separator) gas and liquid handling capacity to estimate the amount of gas that could be safely circulated out from the riser from above the closed BOP’s, without exceeding the MGS capacities and MPD equipment pressure limitations. The paper explains how the PRV sizing calculations were performed which help in specifying the limiting flowrates that the PRV can handle, as a function of mud weight and pressure differential based on API 521b. Lastly the paper illustrates the estimated erosion calculation based on the maximum flowrates that the MPD system could potentially be exposed to due to drilling and/or any limiting riser degassing events, using DNV recommended practices.