bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture Conductivity Calculation Using Mass Balance, Modeling, and Well Performance Data in Saudi Arabian Deep Gas Reservoirs
Authors: Rahim Zillur , Al-Anazi Hamoud , Al-Kanaan Adnan , Kayumov Rifat , Makmun Areiyando
Published: May 2016

The fracture conductivity values reported from the laboratory tests are based on ideal conditions and are usually higher than what actually contributes to production. In reality, the conductivity values are impaired by numerous factors in the reservoir such as high unconfined compressive strength, condensate dropout, proppant embedment, gel damage, etc., and cannot be fully captured in the laboratory measurements. The software models used by the industry to calculate fracture conductivity are specific to certain reservoirs, formations, and/or laboratory conditions and cannot be extrapolated or used for all reservoirs. In this paper, a workflow has been presented to compute fracture conductivity using various techniques and compare them to see what matches closest to reality in terms of well deliverability. First, fracture geometry and conductivity is computed using a mass balance and pressure match. Second, fracture conductivity is computed from the Cinco-Ley correlation and using industry software to estimate at static and dynamic well conditions using closure pressure, actual well performance, and bottomhole flowing pressure measurements. A range of fracture conductivity is computed during initial and later production periods by matching well rate and pressure behavior data. The calculations show the fracture conductivity achieved after a fracture treatment for specific reservoir conditions and how the values change during the production life of a well. Later, correlations relating to productivity increases with reservoir rock and pumping properties are used to optimize fracture treatments such that high rates can be achieved and sustained. The paper also presents different fracturing properties as functions of well productivity that can serve as guidelines for improved application of fracturing technology. Fracture conductivity is one of the most important parameters that impact post-fracture sustained production. Regardless of the formation permeability, higher conductivity values always assist in quicker fracture fluid cleanup and enhanced rate. There are a number of factors that affect the ultimate conductivity achieved in a fracture. They include fracture fluid gel and cross-linker loading, type and size of the proppant, proppant stages, concentration, and pumping sequence, and post-frac fluid cleanup efficiency.

Introduction

Hydraulic fracturing is being used in the Pre-Khuff sandstone reservoirs in Saudi Arabia to achieve higher sustained gas production and sand control in Saudi Arabian gas reservoirs1. The variability in reservoir properties in Pre-Khuff is significant with some areas that are extremely prolific where sanding becomes a major challenge with slight pressure drawdown while other areas that are tight with high compressive strength required long condictive fractures for commercial production.
Unlocking the Secrets of Seismic Anomalies in the Load Transfer Domain
Authors: Selnes Alsing , Edwards Alexander , Whitfield Neil , Waters Kester
Published: May 2016

Introduction

We all know that temperature, pressure and gravity are the main controlling factors of rock properties and elastic properties in the sub-surface. The assumption of a constant gravity around the globe pretty much holds truth, while the other two factors, temperature and pressure, can vary significantly, even within a basin. This again will lead to wrong interpretations of AVO anomalies if not accounted for.

If we focus only on abnormal pressures in the sub-surface, the conception is that it is often associated with trouble; in an exploration sense, it could mean blown reservoir seals and misinterpreted AVO signatures (e.g. Shaker, 2009); for a driller, it could mean excessive time spent fighting formation fluid influxes and/or drilling fluid losses.

Overpressure detection is based on the premise that pore pressure affects compaction-dependent geophysical properties such as density, resistivity, and sonic velocity. Shales are the preferred lithology for pore pressure interpretation because they are more responsive to overpressure than most other rock types. They are also the most abundant of all rock types. Consequently, methods for overpressure detection center around shale deformation behaviour.

The essence of this paper will describe the importance of integration between elastic properties and pressure, and how to better understand and constrain AVO signatures. This is particularly true for how amplitudes in the load transfer domain (Lahann et al., 2011) may differ from what is expected at a given prospect level and thus may be overlooked as false negatives if not accounted for. This is particularly important in a regional context for exploration purposes (e.g. regional studies).

Overpressure mechanisms and elastic responses

The exact same conditions that control the sediments in the sub-surface in terms of elastic properties also control the geo-pressure side of things. A common approach for understanding AVO anomalies with increasing depth is by the use of depth trends (Figure 1) from well log data (Avseth et al., 2008; Japsen et al., 2007). However, one drawback with the common approach is that it only focuses on sands in terms of quartz cementation, and the chemical reactions that has a stiffening effect in shales, related to the smectite to illite (S-I) transformation and related disequilibrium compaction effects, but leaves out load transfer effects.

The same phenomena in shales is described by Thyberg et al. (2009), where Thyberg's assumptions (based on petrographic evidence and well logs) confirm an increase in both density and velocity when entering the chemical compaction window due to S-I diagenesis.
A Real Case of Integrated Multiphase Gathering System Optimization through a Flow Assurance Workflow
Authors: Di Sarra Andrea , Viadana Giorgio , Scaramellini Sara , Bianco Amalia , Masi Silvia
Published: May 2016

Production optimization is one of the most complex and multi-disciplinary task in the Oil & Gas industry. It involves the surface asset during all its production life and requires a continuous improvement process.

Integrated optimization of surface asset, including both gathering facilities and process plant, is a difficult goal to be achieved due to the complexity of such systems and the presence of several variables, uncertainties and operational constraints.

Technology improvements have enabled a widespread use of integrated simulation models for a better asset management according with actual field data.

Production department team of ENI E&P has developed a tool which maximizes production integrating gathering system simulation with process plant simulation. The global optimum is reached through a powerful genetic algorithm that, according to system constraints, allows to control different variables in a simultaneous way.

In fact, steady state simulation environments could bring to unstable field configuration. As a consequence, an updated operative workflow for fluid-dynamic module is needed. This workflow supports the process to select optimized solutions that do not have any criticalities during operation and asset variables upset. This implies that unstable solution are discarded among the investigated ones. Therefore, the obtained maximized production configuration is the global optimum solution (robustness of algorithm) as well as the most stable (fluid-dynamically).

Finally, multiphase transient code analysis allows to understand actual flow regime and, if necessary, to identify mitigative actions for management's improvement of investigated asset.

The integrated workflow has been applied to a real case study. This presents technical contributions of this work for definition of field potential, production optimization, de-bottlenecking activities, asset management.

Introduction

Oil and gas continue to be widely used worldwide as energy resources, because new sources of safe energy have not yet been well developed. These conditions have motivated researchers and workers in the area of oil and gas production to investigate new approaches in the application of optimization methods to maximize gas & oil production rates and to minimize production costs.

The term "Production Optimization" is used to describe different processes in the oil and gas industries. No rigorous definition has been found in the literature, but it means determination and implementation of optimum values of parameters in the production system to maximize hydrocarbon production rate and minimize operating costs under various technical and economical constraints.
Smart Fields - A Decade of Practice in Building Intelligent Fields and Collaboration
Authors: Chai Chon Fui , Van Den Berg Frans G , Engbers Peter
Published: May 2016

Over the past ten years, Shell's Smart Fields programme has built Intelligent Energy capabilities into key field developments and selected brownfields. The capabilities consist of new technologies and new ways of working, which are integrated to provide appropriate technical solutions for asset to become technology enabled from early phase of its development. The global deployment of these capabilities has led to considerable value to the business. New fields in development go through a screening at the early phase of the hydrocarbon maturation process, to identify intelligent energy capabilities valuable to each project.

High value has been achieved from solutions in production surveillance and optimization, smart wells, real time monitoring and optimization and time lapse reservoir surveillance. After some years of Smart Field implementation and value demonstration, the focus of the programme has shifted from "selling" individual solutions to achieving the "Appropriate Level of Smartness" (ALoS) in all key assets and projects.

Integration and new ways of working have been key drivers in the success achieved until now. Collaborative Work Environments (CWEs) have been implemented on a large scale, mostly focusing on the production and field surveillance area and on the real time monitoring. CWEs have improved the cooperation across the boundaries between disciplines and between office and field locations, enabling faster and better decision making. Strong focus has been placed on embedding the new ways of working into the organization. Business value is realized only if the adopted solutions and new ways of working are sustained.

1. Introduction

A Smart Field is an asset or group of assets that can be optimized continuously, managing both surface and subsurface aspects of the field through integrated models and workflows to maximize lifecycle value, while honoring existing operational constraints. This is achieved through an innovative integration of People, Processes and Technology. For more than a decade, Smart Fields has been identifying, developing and implementing integrated solutions that have become standard oil field practices such as Collaborative Work Environment, Smart Well, Reservoir Surveillance solutions in the areas of 4-D seismic and real-time production monitoring to name a few. To date the implementation of Smart Fields solutions have enabled the assets to increase production, reduce deferment, and improve ultimate recovery while reducing costs and HSSE exposure.
Hydraulic Fracturing Across Large Existing Perforated Interval Unlocks Reserves on Tight Sandstone Reservoir: Successful Workover Experience, Onshore Congo
Authors: Martocchia Francesco , Itoua Vignault Rolle , Farina Lisa , Baretti Salvatore , Martini Luca
Published: May 2016

When designing a hydraulic fracturing intervention, the selection of the interval to be perforated is critical in order to maximize oil production and to avoid unwanted gas/water breakthrough from neighboring layers.

While on new wells the perforation interval can be selected carefully analyzing logs and CBL, it can be challenging to design a workover where the HF targets a zone that is right in the middle of a large existing perforated interval (125 meters).

Leaving exposed too many perforations during a fracturing treatment could result in operational issues such as early screenout and/or uncertainties on the fracture initiation point. Zonal isolation could be obtained by cementing part of the perforations but this would mean in permanently losing part of the level.

This paper will describe a successful workover carried on a shut-in oil well, onshore Congo, where a single stage fracturing treatment was performed leaving exposed only few meters of the existing perforations and without permanently losing the remaining intervals.

This result was obtained using a multi-stage ball drop frac completion setting the packers across the perforated interval. The downhole equipment was able to withstand the treating pressure during the fracturing treatment and production was obtained through the frac sleeves.

This workover resulted in a significant oil production from a well that never produced until that moment.

Introduction

In the last decade, hydraulic fracturing has been widely used in Congo for the development of tight reservoirs: since 2007, more than 180 stages have been pumped on 9 different fields with almost one third of these jobs pumped offshore.

All of these treatments have been performed in a wide range of scenarios including: both sandstone and carbonate reservoirs, low to high temperature formations, field rejuvenation and exploration wells.

While applying this technology throughout the years, tailored solutions have been put in place to maximize oil recovery through frac design optimization. This learning curve included:Job design optimization (SPE 151860-MS)Fracture height detection (IPTC 16581-MS)Waterless fluids (IPTC 16640-MS)Completion Strategy and Operations (OTC 19455)Proppant flowback prevention (SPE 169959)

With the encouraging results obtained from the use of hydraulic fracturing, this technology has become the standard completion for tight reservoirs. When dealing with new wells, all aspects of well design, from well trajectory to perforation and completion strategy, are planned in order to optimize the hydraulic fracturing treatment.
Stimulation Through ESP: An Innovative Solution to Improve Production
Authors: Spagnolo Salvatore , Pilone Salvatore , Mauri Luca , Diciaula Giancarlo
Published: May 2016

1. Abstract

Eni is involved in a big project in the Middle East developed with an extensive use of Electrical Submersible Pumps.

The installation of Electrical Submersible Pumps (ESPs) is a common solution in case of depleted reservoirs or where there is demand of high pressure from the surface facilities.

The downside of ESP completions is that they restrict the access to the wellbore for stimulation and cleanup jobs.

The use of a mechanical by-pass (Y-tool) is possible if the production casing/liner is at least 7", and anyway imposes a reduction in the pump size. Moreover, ESPs are also affected by several factors that could lead to definitive failure, like solid plugging or scale depositions.

During the field operations, both ESP stuck by plugging and reduction of productivity index were recorded.

The possibility to perform stimulation jobs through the pump, to avoid the cost of retrieving the completion, was therefore studied as a possible solution even if no past experiences were found in literature and the feedback from the ESP contractors to consider the stimulation trough ESPs only as last chance before a workover.

A dedicated production optimization was created putting together artificial lift and production optimization engineers.

The jobs had to be carefully planned and evaluated case by case, considering that the reliability of all elastomeric and electrical elements downhole (protector, cable, and pothead) could be reduced in case of contact with the stimulation fluid.

Several different interventions were performed: the first ones were aimed at dissolving possible plugs in the pump, starting from simple water or diesel wash and further evolving to more aggressive acid washes.

Extensive lab analyses on the emulsion tendency of the oil lead to attempt also non emulsifier treatments.

This paper will present and detail the successful results experienced in the field, especially in terms of production recovery from stuck pumps and PI improvement.
Real-Time Blending Optimization in Upstream - Operating on the Edge
Authors: Zuluaga Claudia , Law Hiu Ying , Jamil Noor Azman , Bashorun Oladimeji , Phua Pei Huey , Teoh Boon Giap , Briers Jan
Published: May 2016

0. Abstract

Historically, oil and gas producing fields had sufficient capacity to fulfill contractual requirements. Today, most operating companies are finding it ever more challenging to meet contractual requirements on LNG cargos and/or oil tanker loadings. For gas producing assets, the gas produced will feed LNG trains or a power plant directly. And as the feed gas needs to meet specifications on H2S, CO2, Gross Heating Value, etc… there is little room to play. Generally, this blending problem is well understood at the medium to long-term planning level. But, in day-to-day operations, there will be events that force operations to divert from the long-term plan. And this is where Real-Time Asset-Wide Optimization (RT-AWO) comes into play.

This paper details how RT-AWO was deployed and is used in a major Shell operating unit in Asia-Pacific. This asset has a complex gas-producing infrastructure where a combination of different production sharing contracts, third party producers with an ever-changing demand from the LNG plant and strict quality requirements. Having RT-AWO it is now possible to run the field in the most optimal way, all day and every day, while taking into account all possible constraints (wells, topside and pipeline).

The RT-AWO has proven to be very successful. Despite the complexity of the network, the tool is very user-friendly and easy to maintain. Not only does it allow the central control room operators to push the field to the limit, it provides them with accurate CO2 forecasts for up to 18 hours. And it takes less than a minute to compute.

The RT-AWO is a novel approach to a complex problem, sustainable, easy to maintain and use. It provides an integrated view with real-time information, forecasting and optimization functionality. And if is flexible enough to be deployed in other locations with even more complex networks.
The Impact of Broadband Seismic Acquisition and Implications for Interpretation and Reservoir Model Building
Authors: Gehman Carter , Spedding Andrew
Published: May 2016

This paper addresses the impact of acquiring a new 3D Broadband seismic survey over an amplitude-supported, discovered gas field containing legacy 3D conventional towed streamer seismic data. The new seismic data were acquired in shallow water depths using Western Geco's dual level streamer technique and processed through PreSDM. Five gas discovery/appraisal wells with reservoirs ranging from approximately 1.2 to 2.5 s TWT (3,500 ft TVDss to 9,500 ft TVDss) existed prior to broadband acquisition and two additional wells were drilled after acquisition was completed. These seven wells serve as control points that provide a valuable link between the seismic and reservoir properties.

Acquisition of new seismic data was primarily motivated by imaging challenges, particularly in the deeper (>1.6 s TWT) section, to which legacy surveys and (re)processing attempts have failed to completely find a solution. These imaging problems stem from: 1) Abundant shallow gas pockets, which contribute to both amplitude and frequency decay in the underlying image; 2) Fault shadow noise resulting from velocity variations which are difficult to capture in the velocity model; and 3) The presence of sub-regional coal layers having high-impedance contrasts that further attenuate the signal and contribute to generation of multiples. A complimentary paper discusses the novel processing techniques applied to overcome these problems. Here, we discuss the comparative benefit of the broadband acquisition versus the legacy conventional acquisition, namely higher signal to noise ratio throughout the entire record. In this context, we demonstrate through interpretation of broadband data that overall, complex geologic layers are better resolved versus conventionally acquired seismic data. We also compare conventional and broadband wavelets and discuss the implications for layer detection and resolution. This is particularly important for imaging and interpreting thin (<20 ft) reservoirs. We compare horizon-based attribute maps with legacy interpretation and address the implications for reservoir model building. We also apply various degrees of de-multiple algorithms and assess the resultant AVO effects. The broadband data has provided significant uplift in terms of reservoir detection and has thus bolstered confidence in our interpretation of thin, gas charged reservoirs.
Improved Methods for Assessing In Situ Stress in Unconventional Shale Reservoirs in Tectonically Stressed Settings
Authors: Glover Kenneth , Hawkes Robert Vincent , Cui Albert
Published: May 2016

Shale reservoirs are being actively exploited in several tectonically stressed regions around the world. These tectonic settings often mean that the development of these fields requires an adequate quantification of the in situ principle stress magnitudes and their orientation. Achieving this goal can be complicated by the heterogeneous, inelastic, and/or anisotropic mechanical properties of these shales and the associated vertical and lateral variation in pore pressure and stress through the target zones and bounding intervals. For these reasons, the commonly used techniques of determining stress state from mini-frac type data and using this data to calibrate log derived stress profiles may be misleading unless certain additional factors are measured and considered. We present some case study workflow examples from productive shales in tectonically stressed settings where a more rigorous analysis of the injection test data and of the shale petrophysical properties has allowed an improved, more accurate assessment of stress state. In particular, utilizing well testing theory in the analysis of mini-frac data has given us additional understanding of hydraulic fracture behavior in some tectonically stressed shales. Horizontal fracture growth through shear activation of bedding-parallel fabric can be a preferred fracture propagation mechanism in these shales and this behavior can be diagnosed by this improved workflow. Anisotropic mechanical fabric of these shales can be measured in core more regularly and more efficiently due to recent instrumentation advances. These improvements allow for a more accurate distinction between the impact of rock fabric anisotropy and of stress induced acoustic anisotropy on modern sonic logging tool response.
Quantitative Effect of Microporosity on Permeability in Carbonate Reservoirs
Authors: Yu Yibing , Visser Foppe , Amro Mohammed M.
Published: May 2016

Though a rich potential source of tomorrow's oil resources, recovery from carbonate reservoirs is still below the world average recovery factor 35% using existing techniques. The complexity of carbonate pore systems is one of the reasons why conventional recovery techniques generally lead to disappointingly low recovery, which has a negative impact on the economic attractiveness of carbonate development projects.

This paper describes the experimental procedures and workflow to evaluate and analyse the distribution of micro-and macro-porosity in carbonate rock, further more discusses the proposals to extract oil from micropores by CO2 injection. The purpose of the work is to quantify the contribution of each porosity class to the effective rock properties, such as permeability and wettability. High resolution imaging is used to establish the pore size distribution for representative core plugs. MICP and core flood experiments are used to characterize the effective porosity and permeability of the bimodal system.

Detailed understanding of the reservoir properties and fluid flow behavior in microporous carbonates will be a key step in providing improved input data for numerical flow simulations and optimization of the recovery from carbonate oil reservoirs. Moreover, the same understanding is a prerequisite for the planning and execution of EOR projects. This experimental program is the first step in gaining insight in the role played by both porosity classes in controlling multi-phase flow properties in carbonates. In particular, the effectiveness of CO2 in mobilizing fluids from the micro pores will be the subject of further investigation.
Step Change Enhancement of Legacy 2D Seismic Data, an Enabler for Understanding Basin Architecture and Identifying Overlooked Exploration Potential
Authors: Sia Chee Chuan , Bolton Richard , Tion Moniezsa , Lee Audrey Fui Yee , Griffiths Mark
Published: May 2016

Remaining frontier exploration opportunities in otherwise mature areas are almost exclusively covered by legacy seismic data, typically acquired 20 to 30 years ago. Legacy seismic processing often affords a sub-optimal image which compromises the Explorationist's ability to understand basin architecture and subtle, overlooked opportunities.

Algorithm development in seismic processing is continual and usually gradual so reprocessing of data is often perceived as having marginal value. Occasionally step change technologies are developed and it is here that we have the potential to see a significant shift in the understanding of the subsurface. In this paper we examine the impact of two such step change technologies. Recently developed deghosting algorithms allow geophysicists to access signal in notch regions of the frequency spectrum that has previously been discarded. In addition, development in multiple prediction has allowed processors to remove multiple energy where the conditions do not allow for any apparent discrimination between the multiple and primary energy. However, neither the removal of multiple energy nor the improvement in low frequency signal recovery solely accounts for the better images produced. Ancillary processes, notably the accuracy with which seismic velocity can be determined with the wider frequency spectra available also improve to give the more complete picture of the earth.

One such area benefiting from reprocessing of legacy seismic data is West Luconia, offshore Sarawak. West Luconia is a largely underexplored region with sparse well and legacy seismic coverage. The area is structurally and stratigraphically complex and interpretation based on legacy 2D processing does little to move forward understanding of new and overlooked plays. When these new technologies are applied to the legacy seismic, more accurate structure and detailed geometries can be seen throughout the stratigraphy. Enhancement of legacy seismic therefore provides an effective and cost efficient method for understanding remaining exploration potential.

Introduction

West Luconia (Figure 1) is a largely under explored region with limited Well penetrations and sparse legacy seismic coverage. Following initial exploration campaigns in 1970 and 1988, the area has seen limited exploration activity against an industry perception of the region containing limited volume, high risk opportunities with a significant chance of encountering contaminant gasses.

Legacy well penetrations, drilled on limited 2D data have targeted obvious closures but with limited understanding of complex structure and stratigraphy. Continued interpretation based on legacy 2D processing alone does little to move forward this understanding.
Chemical EOR Strategy and Evaluation Approach for a Mid-Life Offshore Field in Peninsula Malaysia
Authors: Sabzabadi A. , Quan D. , Azhan A. , Manap B A , Arsanti D.
Published: May 2016

It is becoming more evident from a number of projects around the world undergoing Chemical EOR (CEOR) that the application is gaining momentum and support from all level of management in both onshore and offshore environments, whilst the latter is still considered to be of "high cost" and "logistical and operational" complex and challenging. As part of decision making process for a mid-life field in an offshore environment, one may require to ascertain whether strategy of framing, assess and selection with risks and uncertainties have clearly been mapped and will lead to a final decision of execution, or the decision is a "given" and in-line with risk appetite of decision makers. Angsi field is an example of process for a mid-life field that is going through a chemical EOR evaluation based on industrial and conventional "staged approach" defined as a technical road map from lab to single well Pilot to full field 3D modeling. Strategy and approach to demonstrate "CEOR process" for Angsi, with lab experiments and pilot project conducted to gather necessary information on key parameters (Sor reduction, Adsorption and operation complexity) to identify and narrow down uncertainties will be discussed in this paper. Furthermore, comparison between waterflood optimisation and infill programs with CEOR will also be briefly discussed. Each stage of the evaluation process is defined and key questions have been asked. The work has been carried out to address uncertainties, identify project risks and minimise or mitigate the impact of risk to the project economics. Sensitivities have mainly been run on remaining oil reduction (Sor), chemical slug size, adsorption and injection start date. Results have shown that chemical EOR is a technically feasible and economically viable option for Angsi from subsurface analysis, incremental recovery and facilities stand point. Therefore, Angsi CEOR application will be the first offshore Alkaline-Surfactant (AS) full field injection in the world.
Assessment of microbial quality of water in popular restaurants in Sylhet city of Bangladesh
Authors: Sarker Ayesha , Dash Sharmista , Hoque Md Mozammel , Ahmed Sultan , Shaheb Md Rayhan
Published: May 2016

Microbial contaminations of drinking water constitute a major burden on human health. Interventions to improve the quality of drinking-water provide significant benefits to health. An assessment of microbial quality of water in the samples obtained from different popular restaurants of Sylhet City Corporation, Bangladesh were analyzed in the laboratory. Our aims were to find out the microbial properties of water, to analyze the potable water qualities of the restaurants and also to compare it with different standards to assess the health risk of people. The microbial tests viz. MPN, TVC and total coliform test were studied. Results revealed that all the water samples were fecal contaminated and had a great chance of contamination by other pathogenic bacteria. Results indicated that most of the samples were significantly positive to MPN test and TVC bacteria were highly significant. The risk score for coliform bacteria also remarked high risk for human health according to WHO standards and were not suitable as potable water. Our recommendations are therefore, water supply authority including restaurant owners should take necessary steps for the maintenance of microbial quality of water and microbial assessments should be done very often to leading a hygienic water distribution environment of the city.Bangladesh J. Agril. Res. 41(1): 115-125, March 2016
Trend and output growth analysis of major fruits in Chittagong region of Bangladesh
Authors: Uddin M Jamal , Dey SR , Taslim Tahmina
Published: May 2016

The study analyzed the trends, growth rates of area, production and yield of major fruits in Chittagong region and identified factors contributing to output growth during 1993/94-2009/10 using secondary data. The fruits under study were mango, jackfruit, litchi, guava, banana, papaya, ber, pomelo, pineapple, watermelon, lime and lemon. The study revealed that the area of all fruits increased over the period except banana, ber, pomelo and water melon. The highest increase in area was estimated for guava (131.6%) and the lowest for jackfruit (6.4%). Similarly, the production of all fruits over the period was increased except banana and pineapple. The average annual growth rates of area, production and yield for all fruits were found to be positive in all periods (i.e, period I: 1993/94-1997/98; Period II: 1998/99-2003/04, and Period III: 2004/05- 2009/10). But the magnitude of the growth rates of area for all fruits varied significantly. The growth rates of area for mango, jackfruit, litchi and pineapple were increased impressively and significantly. This might be due to the adoption of improved variety and management practices by the farmers. The growth rate of area, production and yield of banana decreased drastically over the period due to absence of modern variety of banana and lack of improved management practices in the region. The growth rates of production for mango were found to be highest in the period III (2004/05-2009/10). But the growth rate of yield of mango was found to be decreased significantly over the periods due to improper management against the pest and diseases by the farmers. The highest percentage of output changed was observed in Banana (149%) followed by pineapple (106%) and jackfruit (83%) between the periods. The lowest percentage of output changed was found in guava (11.7%). The contribution of area was the highest in changing output for mango, jackfruit, litchi, guava, ber, pomelo, watermelon, lime and lemon. The contribution of yield was the highest for banana (135.57%), papaya (76.92%) and pineapple (158.62%) for changing output indicated that the increased area was more responsible for changing in output growth of selected fruits. To increase the growth rate of fruits, improved variety and management practices should be disseminated through undertaking special programme and strengthening research-extension linkage in the Chittagong region.Bangladesh J. Agril. Res. 41(1): 137-150, March 2016
Global Justice in Lutheran Political Theology
Authors: Grenholm Carl-Henric
Published: May 2016

The purpose of this article is to examine the contributions that might be given by Lutheran political theology to the discourse on global justice. The article offers a critical examination of three different theories of global justice within political philosophy. Contractarian theories are criticized, and a thesis is that it is plausible to argue that justice can be understood as liberation from oppression. From this perspective the article gives an analysis of an influential theory of justice within Lutheran ethics. According to this theory justice is not an equal distribution but an arrangement where the subordinate respect the authority of those in power. This theory is related to a sharp distinction between law and gospel. The main thesis of the article is that Lutheran political theology should take a different approach if it aims to give a constructive contribution to theories of justice. This means that Lutheran ethics should not be based on Creation and reason alone – it should also be based on Christology and Eschatology.
Globalisation and Global Justice - A Thematic Introduction
Authors: Collste Göran
Published: May 2016

Globalisation involves both promising potentials and risks. It has the potential – through the spread of human rights, the migration of people and ideas, and the integration of diverse economies – to improve human wellbeing and enhance the protection of human rights worldwide. But globalisation also incurs risks: global environmental risks (such as global warming), the creation of new centres of power with limited legitimacy, a ‘race to the bottom’ regarding workers’ safety and rights, risky journeys of thousands of migrants and not least growing global inequalities. Globalisation, therefore, is a key factor for today’s discussions of justice.

As globalisation connects people, it also raises associated responsibilities between them. Until recently, the interest in justice among political philosophers and social ethicists was mainly focused on the nation state. However, this is no longer feasible. Since economic globalisation affects how wealth and power are distributed globally it has become indispensable to discuss social ethics in a global context and to develop principles of global justice. Global justice, therefore, entails an assessment of the benefits and burdens of the structural relations and institutional arrangements that constitute and govern globalisation.

The academic discussion of global justice is vibrant and expanding. In my introduction I provide an overview of the discussions on global poverty, justice, cosmopolitanism and statism, migration, the capability approach and different dimensions of global justice.
Energy Research in Airports: A Review
Authors: Ortega Alba Sergio , Manana Mario
Published: May 2016

The main function of an airport is to provide access to air transport both for passengers and cargo. The number of air operations over the past 20 years has increased rapidly, and this has led to a rise in the energy needs of airports to satisfy this demand. As a consequence, the cost of energy supply for airport managers has escalated. At the same time, global energy consumption has soared due to the needs of emerging countries like China and India, with the consequent environmental impact. This complex scenario of environmental and economic factors has made airport managers become aware of the need to reduce energy consumption as well as a more efficient use of it. The aim of this article is to analyze the main behaviors and energy trends at airports in more recent research, starting with the description of the main energy sources and consumers, the application of energy conservation and energy efficiency measures, the establishment of energy indicators and benchmarking between airports, as well as energy modeling and simulation.
Development of Integrally Molded Bipolar Plates for All-Vanadium Redox Flow Batteries
Authors: Chang Chih-Hsun , Chou Han-Wen , Hsu Ning-Yih , Chen Yong-Song
Published: May 2016

All-vanadium redox flow batteries (VRBs) are potential energy storage systems for renewable power sources because of their flexible design, deep discharge capacity, quick response time, and long cycle life. To minimize the energy loss due to the shunt current, in a traditional design, a flow field is machined on two electrically insulated frames with a graphite plate in between. A traditional bipolar plate (BP) of a VRB consists of many components, and thus, the assembly process is time consuming. In this study, an integrally molded BP is designed and fabricated to minimize the manufacturing cost. First, the effects of the mold design and injection parameters on frame formability were analyzed by simulation. Second, a new graphite plate design for integral molding was proposed, and finally, two integrally molded BPs were fabricated and compared. Results show that gate position significantly affects air traps and the maximum volume shrinkage occurs at the corners of a BP. The volume shrinkage can be reduced using a large graphite plate embedded within the frame.
Market Suitability and Performance Tradeoffs Offered by Commercial Wind Turbines across Differing Wind Regimes
Authors: Chowdhury Souma , Mehmani Ali , Zhang Jie , Messac Achille
Published: May 2016

The suitability of turbine configurations to different wind resources has been traditionally restricted to considering turbines operating as standalone entities. In this paper, a framework is thus developed to investigate turbine suitability in terms of the minimum cost of energy offered when operating as a group of optimally-micro-sited turbines. The four major steps include: (i) characterizing the geographical variation of wind regimes in the onshore U.S. market; (ii) determining the best performing turbines for different wind regimes through wind farm layout optimization; (iii) developing a metric to quantify the expected market suitability of available turbine configurations; and (iv) exploring the best tradeoffs between the cost and capacity factor yielded by these turbines. One hundred thirty one types of commercial turbines offered by major global manufacturers in 2012 are considered for selection. It is found that, in general, higher rated power turbines with medium tower heights are the most favored. Interestingly, further analysis showed that “rotor diameter/hub height” ratios greater than 1.1 are the least attractive for any of the wind classes. It is also observed that although the “cost-capacity factor” tradeoff curve expectedly shifted towards higher capacity factors with increasing wind class, the trend of the tradeoff curve remained practically similar.
Experiments on the Performance of Small Horizontal Axis Wind Turbine with Passive Pitch Control by Disk Pulley
Authors: Chen Yu-Jen , Shiah Y.
Published: May 2016

The present work is to design a passive pitch-control mechanism for small horizontal axis wind turbine (HAWT) to generate stable power at high wind speeds. The mechanism uses a disk pulley as an actuator to passively adjust the pitch angle of blades by centrifugal force. For this design, aerodynamic braking is caused by the adjustment of pitch angles at high wind speeds. As a marked advantage, this does not require mechanical brakes that would incur electrical burn-out and structural failure under high speed rotation. This can ensure the survival of blades and generator in sever operation environments. In this paper, the analysis uses blade element momentum theory (BEMT) to develop graphical user interface software to facilitate the performance assessment of the small-scale HAWT using passive pitch control (PPC). For verification, the HAWT system was tested in a full-scale wind tunnel for its aerodynamic performance. At low wind speeds, this system performed the same as usual, yet at high wind speeds, the equipped PPC system can effectively reduce the rotational speed to generate stable power.
Rationalizing the GMO Debate: The Ordonomic Approach to Addressing Agricultural Myths
Authors: Hielscher Stefan , Pies Ingo , Valentinov Vladislav , Chatalova Lioudmila
Published: May 2016

The public discourse on the acceptability of genetically modified organisms (GMOs) is not only controversial, but also infused with highly emotional and moralizing rhetoric. Although the assessment of risks and benefits of GMOs must be a scientific exercise, many debates on this issue seem to remain impervious to scientific evidence. In many cases, the moral psychology attributes of the general public create incentives for both GMO opponents and proponents to pursue misleading public campaigns, which impede the comprehensive assessment of the full spectrum of the risks and benefits of GMOs. The ordonomic approach to economic ethics introduced in this research note is helpful for disentangling the socio-economic and moral components of the GMO debate by re- and deconstructing moral claims.
Estimating Nitrogen Load Resulting from Biofuel Mandates
Authors: Alshawaf Mohammad , Douglas Ellen , Ricciardi Karen
Published: May 2016

The Energy Policy Act of 2005 and the Energy Independence and Security Act (EISA) of 2007 were enacted to reduce the U.S. dependency on foreign oil by increasing the use of biofuels. The increased demand for biofuels from corn and soybeans could result in an increase of nitrogen flux if not managed properly. The objectives of this study are to estimate nitrogen flux from energy crop production and to identify the catchment areas with high nitrogen flux. The results show that biofuel production can result in an increase of nitrogen flux to the northern Gulf of Mexico from 270 to 1742 thousand metric tons. Using all cellulosic (hay) ethanol or biodiesel to meet the 2022 mandate is expected to reduce nitrogen flux; however, it requires approximately 25% more land when compared to other scenarios. Producing ethanol from switchgrass rather than hay results in three-times more nitrogen flux, but requires 43% less land. Using corn ethanol for 2022 mandates is expected to have double the nitrogen flux when compared to the EISA-specified 2022 scenario; however, it will require less land area. Shifting the U.S. energy supply from foreign oil to the Midwest cannot occur without economic and environmental impacts, which could potentially lead to more eutrophication and hypoxia.
Genome-Wide Transcriptome Profiling of Mycobacterium smegmatis MC2 155 Cultivated in Minimal Media Supplemented with Cholesterol, Androstenedione or Glycerol
Authors: Li Qun , Ge Fanglan , Tan Yunya , Zhang Guangxiang , Li Wei
Published: May 2016

Mycobacterium smegmatis strain MC2 155 is an attractive model organism for the study of M. tuberculosis and other mycobacterial pathogens, as it can grow well using cholesterol as a carbon resource. However, its global transcriptomic response remains largely unrevealed. In this study, M. smegmatis MC2 155 cultivated in androstenedione, cholesterol and glycerol supplemented media were collected separately for a RNA-Sequencing study. The results showed that 6004, 6681 and 6348 genes were expressed in androstenedione, cholesterol and glycerol supplemented media, and 5891 genes were expressed in all three conditions, with 237 specially expressed in cholesterol added medium. A total of 1852 and 454 genes were significantly up-regulated by cholesterol compared with the other two supplements. Only occasional changes were observed in basic carbon and nitrogen metabolism, while almost all of the genes involved in cholesterol catabolism and mammalian cell entry (MCE) were up-regulated by cholesterol, but not by androstenedione. Eleven and 16 gene clusters were induced by cholesterol when compared with glycerol or androstenedione, respectively. This study provides a comprehensive analysis of the cholesterol responsive transcriptome of M. smegmatis. Our results indicated that cholesterol induced many more genes and increased the expression of the majority of genes involved in cholesterol degradation and MCE in M. smegmatis, while androstenedione did not have the same effect.
Exchange Transfusion in the Treatment of Neonatal Septic Shock: A Ten-Year Experience in a Neonatal Intensive Care Unit
Authors: Pugni Lorenza , Ronchi Andrea , Bizzarri Bianca , Consonni Dario , Pietrasanta Carlo , Ghirardi Beatrice , Fumagalli Monica , Ghirardello Stefano , Mosca Fabio
Published: May 2016

Septic shock, occurring in about 1% of neonates hospitalized in neonatal intensive care unit (NICU), is a major cause of death in the neonatal period. In the 1980s and 90s, exchange transfusion (ET) was reported by some authors to be effective in the treatment of neonatal sepsis and septic shock. The main aim of this retrospective study was to compare the mortality rate of neonates with septic shock treated only with standard care therapy (ScT group) with the mortality rate of those treated with ScT and ET (ET group). All neonates with septic shock admitted to our NICU from 2005 to 2015 were included in the study. Overall, 101/9030 (1.1%) neonates had septic shock. Fifty neonates out of 101 (49.5%) received one or more ETs. The mortality rate was 36% in the ET group and 51% in the ScT group (p = 0.16). At multivariate logistic regression analysis, controlling for potentially confounding factors significantly associated with death (gestational age, serum lactate, inotropic drugs, oligoanuria), ET showed a marked protective effect (Odds Ratio 0.21, 95% Confidence Interval: 0.06–0.71; p = 0.01). The lack of observed adverse events should encourage the use of this procedure in the treatment of neonates with septic shock.