bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accounting for Fluid Property Variations in Temperature Transient Analysis
Authors: Mao Yilin , Zeidouni Mehdi 
Published: May 2017

Abstract
Significant fluid property variation can be induced due to pressure and temperature dynamics in the reservoir associated with oil production. The existing analytical solutions for temperature transient analysis generally assume constant fluid properties, which can be invalid especially for cases of high drawdown and strong temperature signals. In this study, we present a method to account for the fluid property variations in temperature transient analysis. The method introduces corrections on fluid property values as input for analytical solutions. The corrections are performed on four identified fluid properties in an iterative manner which can be easily implemented in available temperature analysis procedures. To validate the developed approach, we model drawdown and buildup transient temperature signals with the fluid property correction method for non-damaged and damaged reservoirs under different production rates and reservoir fluid compositions. The analytical modeling results are compared with numerical simulations. In addition, by finding the dominating fluid property, a simplified approach of property correction is presented. Through application to example problems, we show that using fluid property correction method presented herein can improve the permeability estimations by 60% for the conditions considered in this paper. We present a modified method to damaged reservoirs which results in additional 25% improvements on the permeability estimations. With these improvements, the applicability of temperature transient analysis using analytical solutions can be extended from cases with limited sandface temperature signals of a few degC to stronger signals of 20-30 degC.
Benefits of Real-Time Production Optimization for a Complex Offshore Multi-Field Asset in Brazil
Authors: Hoffmann A.. , Sunjerga S.. , Teixeira A.. , Silva T. L. , Camponogara E.. 
Published: May 2017

Abstract
Developing Oil & Gas assets requires planning production on multiple horizons: (1) the long-term production plan includes strategic decisions for technology and recovery strategies to maximize the Net Present Value (NPV) of the project, (2) the mid-term horizon includes the drilling program and reservoir depletion/injection rates and (3) the short-term optimization (real-time production optimization or RTPO) aims to maximize the usage of the existing facilities. In the case of RTPO, both subsurface and surface systems are important, the goal being to maximize the daily production while honoring all operational constraints.
RTPO requires a comprehensive integrated model covering the entire production system and an accurate mathematical formulation of the problem. This implies finding an appropriate optimization strategy and solver to find an optimal solution within a reasonable time. Sustainable production optimization solutions also assume continuous model update, maintenance and improvement, as the production system behavior changes over time.
In this paper, we develop an integrated model for a complex multi-field asset. The production system includes 12 gas wells, 24 gas-lifted oil wells, 4 gas-injection wells, 4 CO2-injection wells, subsea manifolds, gas pipelines, offshore process facilities and CO2 removal units. Gas production from each field is gathered in a single gas pipeline system connected to a gas processing facility located onshore. Control variables include wellhead pressures, routing of wells, gas lift rates, flaring and re-injection rates. Many capacity, pressure and compositional constraints are considered through the whole production system.
The production optimization model including binary variables and non-smooth non-linear functions is rather challenging to solve. Each part of the integrated model is approximated with multidimensional piecewise-linear functions to a desired degree of accuracy. The resulting Mixed Integer Linear Program (MILP) can be solved efficiently with existing commercial solvers. The optimization solution is used to answer different types of challenge: (1) platform start-up, (2) unexpected failure of a gas compressor, (3) maintenance on a group of wells and (4) changing reservoir conditions. Production increase driven by RTPO ranges from 1 to 5 % with no additional CAPEX. The implementation of the production optimization solution is also discussed. The importance of the usability, user training and solution maintenance is highlighted.
Multiwell Operational Performance Benchmarking: A Continuous Drilling Optimization Approach for a Brownfield Drilling Project in Malaysia
Authors: Goo Jia Jun , Abdul Rahman Nor Nabilah , Cavallini Alberto , El-Yamany Yasser , Azmily Ahmad Helmi , Mohd Shah Zainudin Ahmad Haziq 
Published: May 2017

Abstract
Multiwell drilling performance benchmarking delivers an accurate understanding of well construction performance across multiple wells by computing and comparing drilling-specific key performance indicators (KPIs). It also provides systematic enforcement of technical limits in various operations. The benchmarking workflow involves intelligent measuring techniques with an embedded automated rig operations detection algorithm. The analysis of data from rig sensor and operation reports from multiple teams enables the evaluation of every drilling activity with high degree of granularity. Effective KPIs are created to pinpoint the best way to optimize procedures and reduce invisible lost time and nonproductive time. The performance benchmarking from this unbiased system generates detailed metrics for consistent comparison of well construction processes, including flat-time operations, with pre-agreed targets calibrated from historical performance involving multiple rigs, wells, and crews. This approach continuously drives the team to work towards the technical limit of their operations by identifying lost time and adopting innovative drilling practices. For an operator in a brownfield, offshore Malaysia, there was previously no daily tracking of operational performance that could be shared immediately with the crew. This new approach stimulates awareness among the crews to perform consistently. Furthermore, the best practices are discussed regularly before a crew change or a job to ensure the same or improved level of performance. Wells drilled during the recent seven-well drilling campaign have adopted this workflow as part of new operator excellence and "drilling the limit" initiatives, which has translated to a more than 20% reduction in invisible lost time. Overall, the total well construction days has been reduced compared to the plan, and the 10% cost saving of the authorization for expenditure (AFE) provided clear reveal of this new drilling optimization method with the support of dedicated performance engineers. The database of improved drilling parameters will promote better planning for the next stage of enhanced oil recovery (EOR) and the future development campaign. This method also empowers an in-depth probabilistic approach for planning new wells and provides a more accurate prediction of well time for AFEs planning. This system serves as a platform for measuring the performance of ongoing operations and provides consistent, fact-based decisions for selecting the ideal operating approach for each well.
Modelling of Gas Production from Shale Matrix to Fracture Network
Authors: Kudapa Vamsi Krishna , Kumar Shashank , Gupta Dharmendra Kumar , Sharma Pushpa , KunhAbdulla Rubna 
Published: May 2017

Abstract
The main objective of this paper is to study the flow rate variation of the shale matrix while the gas is flowing from the shale matrix to the fracture network. For this a non-linear PDE equation has been developed, which involves the Klinkenberg Effect, Non-Darcy Flow and Adsorption/Desorption.
This paper mainly discusses about the modeling of gas flow from the matrix to the wellbore. The representation of the reservoir model includes a cube as a porous media i.e. it contains pore spaces in which free gas is stored and also the adsorbed gas. Now, the gas in the cube (both free gas and adsorbed gas) will start flowing out inside the matrix to the fractures (induced). Many of these cube representations are put together and connected to the well bore. In this paper, we have considered a dual porosity model. One porosity is the combination of matrix and natural fracture and the second porosity is the hydraulic fracture. For this model, a non-linear PDE equation has been developed which is then compiled using JAVA to develop a simulator for calculating the shale gas production, by considering the matrix as a source term. The production data that is obtained from this model will describe the unique characteristics of shale gas reservoirs.
A study on the role of natural fractures on production is done, by considering an updated dual mechanism and dual porosity model. Also the effect of hydraulic fractures on production has been studied. The obtained production results are also compared with the normal dual porosity model. Moreover, the results are also compared by developing a model in CMG-IMEX simulator.
The novelty lies in the fact that the proposed updated dual mechanism and dual porosity model provides better results when compared with the previous dual porosity models. This model will be helpful for the oil and gas industries to know the production rates during the lifetime of the reservoir.
Targeting PPARalpha in Alzheimer's Disease
Authors: D'Orio Barbara , Fracassi Anna , Paola Cerù Maria , Moreno Sandra 
Published: May 2017

Background:
The molecular mechanisms underlying Alzheimer's disease (AD) are yet to be
fully elucidated. The so-called “amyloid cascade hypothesis” has long been the prevailing paradigm for
causation of disease, and is today being revisited in relation to other pathogenic pathways, such as oxidative
stress, neuroinflammation and energy dysmetabolism. The peroxisome proliferator-activated receptors
(PPARs) are expressed in the central nervous system (CNS) and regulate many physiological
processes, such as energy metabolism, neurotransmission, redox homeostasis, autophagy and cell cycle.
Among the three isotypes (α, β/δ, γ), PPARγ role is the most extensively studied, while information on α
and β/δ are still scanty. However, recent in vitro and in vivo evidence point to PPARα as a promising
therapeutic target in AD.

Conclusion:
This review provides an update on this topic, focussing on the effects of natural or synthetic
agonists in modulating pathogenetic mechanisms at AD onset and during its progression. Ligandactivated
PPARα inihibits amyloidogenic pathway, Tau hyperphosphorylation and neuroinflammation.
Concomitantly, the receptor elicits an enzymatic antioxidant response to oxidative stress, ameliorates
glucose and lipid dysmetabolism, and stimulates autophagy.
A Systematic Review of the Prevalence and Associations of Limited Health Literacy in CKD
Authors: Taylor Dominic M. , Fraser Simon D.S. , Bradley J. Andrew , Bradley Clare , Draper Heather , Metcalfe Wendy , Oniscu Gabriel C. , Tomson Charles R.V. , Ravanan Rommel , Roderick Paul J. ,   on behalf of the ATTOM investigators
Published: May 2017

Background and objectives
The self-management and decision-making skills required to manage CKD successfully may be diminished in those with low health literacy. A 2012 review identified five papers reporting the prevalence of limited health literacy in CKD, largely from United States dialysis populations. The literature has expanded considerably since.

Design, setting, participants, & measurements
We used systematic review, pooled prevalence analysis, metaregression, and exploration of heterogeneity in studies of patients with CKD (all stages).

Results
From 433 studies, 15 new studies met the inclusion criteria and were analyzed together with five studies from the 2012 review. These included 13 cross-sectional surveys, five cohort studies (using baseline data), and two using baseline clinical trial data. Most (19 of 20) were from the United States. In total, 12,324 patients were studied (3529 nondialysis CKD, 5289 dialysis, 2560 transplant, and 946 with unspecified CKD; median =198.5; IQR, 128.5–260 per study). Median prevalence of limited health literacy within studies was 23% (IQR, 16%–33%), and pooled prevalence was 25% (95% confidence interval, 20% to 30%) with significant between-study heterogeneity (I
2=97%). Pooled prevalence of limited health literacy was 25% (95% confidence interval, 16% to 33%; I
2=97%) among patients with CKD not on dialysis, 27% (95% confidence interval, 19% to 35%; I
2=96%) among patients on dialysis, and 14% (95% confidence interval, 7% to 21%; I
2=97%) among patients with transplants. A higher proportion of nonwhite participants was associated with increased limited health literacy prevalence (P=0.04), but participant age was not (P=0.40). Within studies, nonwhite ethnicity and low socioeconomic status were consistently and independently associated with limited health literacy. Studies were of low or moderate quality. Within-study participant selection criteria had potential to introduce bias.

Conclusions
Limited health literacy is common in CKD, especially among individuals with low socioeconomic status and nonwhite ethnicity. This has implications for the design of self-management and decision-making initiatives to promote equity of care and improve quality. Lower prevalence among patients with transplants may reflect selection of patients with higher health literacy for transplantation either because of less comorbidity in this group or as a direct effect of health literacy on access to transplantation.
News Note: Media '75 Conference
Authors: Beattie Earle 
Published: May 2017

'PEOPLE-EVENT' BIAS cont. was eminently a technical problem that could be resolved by government engineers co-operating with their corporate counter-parts to devise the most efficient pollution-control methods, and to minimize their adverse effect on the financial health of the industry. And so, I was hardly surprised when one top official in the then Air Management Branch told me that his people take polluters to court only as a last resort, after all avenues of co-operation, moral suasion, and coercion have been exhausted. When it comes to recalcitrant corporations, the Ministry considers even very slow progress a more efficient way of cleaning up the environment than lengthy and expensive court proceedings. In other words, it is the world-view of engineers that technical problems demand technical solutions, and scientists are much more qualified trouble-shooters than lay people in the fields of law, politics, or journalism.
Development of a Microcontroller-Based 6/12/18/24V Power Inverter Circuit
Authors: Ogunseye Abiodun , Johnson Daniel Ogheneovo 
Published: May 2017

A power inverter circuits is normally designed to meet its design specifications when the applied input DC voltage is within specified tolerance limits. Thus, single input inverters are usually specified to work from a DC source having a fixed nominal voltage. This limits the usefulness of the inverter circuit when a DC source having the specified nominal voltage is not available. In this work, a modified square wave inverter system that is specified to work properly from batteries with nominal voltages of 6, 12, 18 and 24 V was designed. A model of the microcontroller-based circuit was developed with Proteus® software and its firmware was written in C language using the MicroC® development tool. A prototype of the circuit was constructed and then tested. The constructed circuit was found to work properly by producing a 50 Hz modified square waveform when it was powered from batteries having nominal voltages of 6 V, 12 V, 18 V and 24 V.
Faster Aspart Versus Insulin Aspart as Part of a Basal-Bolus Regimen in Inadequately Controlled Type 2 Diabetes: The onset 2 Trial
Authors: Bowering Keith , Case Christopher , Harvey John , Reeves Michael , Sampson Michael , Strzinek Robert , Bretler Ditte-Marie , Bang Rikke Beck , Bode Bruce W. 
Published: May 2017

OBJECTIVE
This multicenter, double-blind, treat-to-target, phase 3 trial evaluated the efficacy and safety of fast-acting insulin aspart (faster aspart) versus insulin aspart (IAsp) in adults with type 2 diabetes receiving basal insulin and oral antidiabetic agents.

RESEARCH DESIGN AND METHODS
The primary end point was HbA1c change from baseline after 26 weeks’ treatment. After an 8-week run-in to optimize basal insulin, subjects were randomized (1:1) to mealtime faster aspart (n = 345) or IAsp (n = 344), titrated using a simple daily patient-driven algorithm, plus insulin glargine U100 and metformin.

RESULTS
HbA1c change was –1.38% (faster aspart) and –1.36% (IAsp); mean HbA1c was 6.6% for both groups. Faster aspart demonstrated noninferiority versus IAsp in reducing HbA1c (estimated treatment difference [ETD] [95% CI] –0.02% [–0.15; 0.10]). Both treatments improved postprandial plasma glucose (PPG) control; the PPG increment (liquid meal test) was statistically significant in favor of faster aspart after 1 h (ETD [95% CI] −0.59 mmol/L [−1.09; −0.09]; −10.63 mg/dL [−19.56; −1.69]; P = 0.0198), but not after 2–4 h. Change from baseline in fasting plasma glucose, body weight, and overall severe/blood glucose–confirmed hypoglycemia rates (rate ratio [RR] [95% CI] 1.09 [0.88; 1.36]) were similar between treatments. Postmeal hypoglycemia (0−2 h) rates were 2.27 (faster aspart) and 1.49 (IAsp) per patient-year of exposure (RR [95% CI] 1.60 [1.13; 2.27]).

CONCLUSIONS
Faster aspart and IAsp were confirmed noninferior in a basal-bolus regimen regarding change from baseline in HbA1c. Faster aspart improved 1-h PPG with no differences in 2−4-h PPG versus IAsp. Overall hypoglycemia rates were similar except for an increase in 0−2-h postmeal hypoglycemia with faster aspart.
Low-Cost Instrument for Tracing Current-Voltage Characteristics of Photovoltaic Modules
Authors: Vicente Leite  , José Batista  , Faustino Chenlo  , João L. Afonso  
Published: May 2017

This paper presents a simple, robust and low-cost instrument for tracing current- and power-voltage characteristics of photovoltaic modules or low voltage strings using either an oscilloscope or a LabVIEW application developed for this purpose. It consists of a flexible electronic circuit, developed from a previous work, based on a fast varying load, built with a power MOSFET, which is controlled by means of a suitable gate-source voltage control signal in order to improve the tracing of current- and power-voltage characteristics on an oscilloscope. The new developments of this work include a low-cost DAQ system and an application developed in LabVIEW, which enhances the functionalities and flexibility of the current-voltage tracer. The robustness was strongly improved in view of field tests for fault diagnosis analysis. All details of the electronic circuit are shown in this paper and experimental results obtained with the new instrument are presented.
Application of Trigeneration to a Multi-Unit Residential Building in Canada
Authors: D. Allaire-Tanguay  , N. Galanis  , R. Sunyé  
Published: May 2017

This paper presents the model developed to compare a trigeneration system to existing heating, cooling and electricity generation methods. The archetype of a typical 13 storey multi-unit residential building has been simulated in TRNSYS with an array of commercially available cogeneration units. These units provide the required heating to the building through water storage and produce electricity as a subsidiary. During cooling periods heat from these units fuels a combination of absorption machines modelled especially for this application. Results show a reduction of primary energy consumption compared to an actual scenario. Further analysis of the controls and storage size would be required to optimize this system.
Multi-Objective Optimization of Microgrid Frequency and Energy Storage Capacity
Authors: M. Kohansal  , G. B. Gharehpetian,  , M. Rahmatian  , M. J. Sanjari  
Published: May 2017

Microgrids are systems to integrate renewable and conventional distributed energy resources under one control system. These elements are responsible for microgrid stability during and after occurrence of disturbances. The frequency stability is one of the most important issues investigated recently, specifically during islanding process. In this paper, a multi-objective function is presented and optimized byImperialistic Competitive Algorithm to improve the frequency behaviour of the microgrid considering the energy storage capacity.
Power System Monitoring using Phasor Measurements
Authors: P. Chusovitin  , A. Pazderin  
Published: May 2017

The paper describes investigation of the new opportunities for power system monitoring and control using phasor measurements. Phasor measurements are used for power system model identification in the form of state-space model. Implementing the modal analysis to identified state-space model gives the opportunity to control proximity of the operation point to the feasibility boundary. Also, identified state-space model allows predicting power system transient. All time domain simulations of the research are conducted for two-generator-swing-bus system. Calculations were carried out in Matlab.
Voltage-induced stresses during Low Voltage Ride Through (LVRT) in the drive train of wind turbines with DFIG
Authors: Dr.-Ing. Jan Wenske  , Prof. i.R. Dr.-Ing. habil. Ulrich Beckert  
Published: May 2017

Nowadays stochastic occurrence of main grid disturbances (LVRT, FRT) leads to high level vibrational excitation of the drive train during operation of wind turbines. Regardless of the drivetrain design as a direct, hybrid or multi-stage geared one in this case high mechanical and electrical stresses should be expected. This voltage-induced stress resulting from the generator-load input function, in which the air gap torque of the generator changes with high dynamic rates. The momentum is sufficient to excite any significant natural frequencies of the above-mentioned power train variants and of all mechanically coupled systems, such as the rotor blades, main frames, nacelle and tower structures. The effects within the drivetrain are shown by simulation by means of a physically discretized torsional oscillator model of a typical multi-megawatt wind turbine with a conventional multi-stage gearbox and fast running DFIG drivetrain design. A general method for a controller setting will be discussed to handle these abormal grid side conditions. Using FOC for the DFIG-converter system electrical stress will be limited by the rotor current control.
Renewable Energy in Residential Buildings Analysis of different micro-generation systems
Authors: M. Rodrigues  , M. Valdez  , D. Coelho  
Published: May 2017

Portugal has to meet a target of 31% regarding the share of renewable sources on gross final energy consumption, including 10% in transportation, to meet the targets imposed on greenhouse gas emissions, energy efficiency and use of renewable energy by the European Commission Climate Change and Energy package for 2020 The implementation of the new National Strategy for Energy – ENE 2020, defining an agenda for competitiveness, growth and energy and financial independence, by investing on renewable energies and promoting the energy efficiency, assuring the security of supply and the economical and environmental sustainability of the national energy model; contributing to the reduction of CO2 emissions, will enable Portugal to meet commitments assumed within the context of European policies. In the National Action Plan for Energy Efficiency Portuguese Government stated the goal of achieving 165 MW of micro-generation installed capacity by the year of 2015. In this context, and according to the new Portuguese law concerning micro-generation to promote renewable energy sources in households, we present in this paper a technical-economic analysis of different micro-generation systems that can be installed in a single-family house. This analysis will take into account the local availability of renewable resources and market technologies.