bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Volcanic Reservoir - New Integrated Approach: A Case Study from Raageshwari Deep Gas Field, Rajasthan, India
Authors: Chowdhury Manabesh , Guha Rupdip , Singh Surender , Verma Sumil Kumar , Tandon Rohit , Gould Thomas , Taylor Andrew , Goodall Ian
Published: May 2016

The Raageshwari Deep Gas Field is located in the Central Basin High, in the southern part of the Barmer Basin, Rajasthan, India. The major reservoirs are eruptive volcanics and subsequently deposited clastics of Cretaceous - Early Tertiary age. The reservoirs are micro porosity-low permeability gas condensate systems. Exploration wells were conventionally tested with gas production rates of 2–4 MMScf/day at high drawdowns. In the development phase, deviated wells with multi-stage hydraulic fracturing have shown multi-fold improvement in production performance.

Volcanic reservoirs are characterized by quick changes of lithofacies both laterally and vertically resulting in strong vertical and horizontal heterogeneity. Unpredictable distributions of pore and fracture networks resulted in variable well performance and productivities. Difficulties in reservoir characterization pose an immense challenge to effective well and reservoir management.

Comprehensive reservoir characterization studies were undertaken to unravel the complexity of the volcanic reservoirs and to capture the uncertainties. The workflow integrates data from volcanic outcrop analogues, conventional core (visual description, thin section petrography, geochemistry, RCA, Dean Stark and SCAL), mudlogs (gas shows and chromatography), and wireline logs including dipole sonic, image and NMR logs. Productive reservoir units deliverability was validated with production logs, whereas the effectiveness of hydraulic fracturing was matched with micro-seismic data coupled with seismic attributes (AntTrack volume). Matrix permeability coupled with fracture characterization was used to match well performance. Spatial distributions of reservoir properties were populated by geostatistical techniques incorporating available geometries and flow unit dimensions from analogues and well information.

The validity of this approach has been confirmed with most recent wells as blind tests and a successful production test from a deeper unit. The approach also emphasises the importance of integrating different datasets for detailed reservoir characterization leading to increased confidence in effective reservoir management of this complex reservoir.
Exception-Based Surveillance - Integrating Well Models, Real Time Production Estimates and Hydrocarbon Accounting Tool in Well Operating Envelopes to Ensure Optimal Well Production within Safe Limits
Authors: Sahu Sambit , Singh Ankur , Al Balushi Mahmood , Konwar Anupam , Bahukhandi Naveen , Briers Jan
Published: May 2016

On a daily basis, the Well, Reservoir and Facility Management (WRFM) team screens all producer and injector wells to identify those wells that are under-performing or outside safe operating limits. A 'Well Operating Envelope' tool has been developed, focused on establishing the boundary conditions of various safety-critical parameters and optimized well performance. Current well operating conditions, derived from real-time gauges and flow estimates from Production Universe (PU), are monitored vis-à-vis these parameters via this tool to identify the "problematic" wells.

Various diagnostic tools (i.e. Surface P-Q curves, VLP-IPR Nodal Analysis, Tulsa Flowline erosion model, Gas-Lift response curve, Inflow performance, SC-SSSV pressure plot and Hall plot derivatives) have been used and visualized for better understanding of the well flowing conditions for both production and injection systems. This tool fetches data from multiple databases like Data Historian, Energy Components and Production Universe (PU); it is also capable of interfacing with Prosper and WinGlue to fetch well performance data automatically.

Following improvements have been observed with implementation of this tool:Traffic light and graphical representation enables quick well surveillance in identifying problematic wells and taking corrective measures.Monitoring of the daily PU estimated production vis-à-vis well tests, allocated production volumes and the physical well models will increase hydrocarbon accounting efficiency.Monitoring real-time parameters like FTHP, FBHP, and flowrates allows the Petroleum Engineers and Operations to operate safely within defined boundaries.Monitoring of parameters like GOR, drawdown will enable adherence to reservoir management guidelines and reduce potential reserve losses.

Visualization of information from multiple data sources into this real-time tool provides an effective and efficient monitoring to ensure optimal well production within safe limits on a day-to-day basis for well, reservoir and facility management.
A Dynamic Discrete Fracture Model for Simulation of Tight Low-Permeability Reservoirs
Authors: Lei Zhengdong , Tian Changbing , Wang Fang , Wang Wenhuan , Peng Huanhuan , Wang Tingting , Li Qianshan , Yu Zhu
Published: May 2016

Tight Low-Permeability reservoirs are characterized by natural fractures and hydraulic fractures, fractures frequently generated in injectors during long-term waterflooding operations. These fractures may have a significant impact on process performance and ultimate recovery. It is a great challenge to model accurately fluid flow between multi-scale, dynamic fractures and tight matrix rock.

In this paper, we develop a dynamic discrete Fracture modeling approach (DDFM) to simulate complicated flow through multiple fractures and tight matrix rock. The discrete fracture modeling (DFM) approach is applied to describe realistic large-scale fractures individually and explicitly. This entails highly constrained unstructured gridding and construction of a transmissibility list of all neighboring cells. The micro-fracture system is modeled by permeability sensitive to the stress change to resolve dynamic opening and closing. A fracture growth model was developed that incorporates the effect of geo-mechanical impact by injection pressure and injection-production ratio, which can simulate the formation of fractures and update the unstructured grid in a timely manner. The new model allows us to better understand the multi-scale and multi-physics flow behavior caused by complex fracture system.

The simulation results show that reservoir dynamic fractures play an important role in both direction and speed of water displacement fronts through tight low-permeability reservoirs. The oil recovery rate can increase or decrease significantly depending on the fractures orientation and the rate of fracture growth. The proposed simulation method provides a useful tool for modeling the effect of fractures on waterflooding performance and can be used to optimize injection pressures and rates, water quality as well as well patterns for maximizing oil recovery.

1 Introduction

Tight Low-Permeability reservoirs have low permeability and tiny pores. The long-term waterflooding operation always leads to a pressure increase near the wellbore. Because of the increase in pressure, most injection wells will generate dynamic fractures. These fractures generate during waterflooding operations and expand gradually over time, which seriously influence the reservoir performance and sweep efficiency. So the fracture propagation needs to be analyzed. The fracture length in conventional models was constant, so how to describe and simulate the dynamic change of fractures poses a challenge to discrete fracture modeling.
Empowering Women in the Oil and Gas Industry
Authors: Hii Rebecca Pek Cheah , Kardani Ilen , Bt. A. Jalil Nurlili Elilza , N. Kiek Joseph Ngieng , Chan Wei Chze
Published: May 2016

Although women comprise a portion of the talent pool that makes up the oil and gas industry, historically, more men occupy roles within the sector. Additionally, challenges faced by women in comparison to men within the industry vary in terms of severity. While all areas within the oil and gas industry promote female recruitment, there is a perceived gap with respect to retaining females while providing them with career growth opportunities equivalent to those of male colleagues. A common goal amongst women within the industry is to achieve a work/life balance, to which various obstacles can be encountered related to movement to geographical locations, cultural differences, mobility, dual careers, work type, and family preferences.

Gender diversity is an important driver for employing females within in every segment of the oil and gas industry to help obtain a broader perspective while driving an organization's growth and capability. This is particularly important because women comprise a roughly equal percentage of the available workforce with equivalent levels of education to their male counterparts.

Women are capable of performing all industry roles during operations both on and offshore from finance to field engineering, operating to upper management. This paper highlights challenges faced by women within the oil and gas industry within varying roles and positions while striving to maintain a work/life balance, without sacrificing the prospects of career development. The goals is to help provide clear information related to working conditions and challenges to help increase the number of women joining the oil and gas industry.

The Petroleum Industry is Seeking Talent

Based on an annual energy outlook study (U.S. Energy Information Administration 2014), the demand for energy for the next 25 years will continue to increase parallel to the population growth, as shown in Table 1.
Tractor Production Logging in Long Cased Horizontal Wells; Operational Experience from the Al Shaheen Field, Offshore Qatar
Authors: Frans Frederic , Cuauro Antonio , Chalco Edgardo , Brink David , Ghozali Muhammad , Bounoua Noureddine
Published: May 2016

Production logging in ultra-long horizontal wells has long been recognized to be extremely challenging, both in terms of data acquisition and data interpretation. This paper describes the planning, execution and lessons learnt of an incident free production/injection logging (PLT) campaign completed in twelve shallow horizontal wells – water injectors and oil producers – to support the long term reservoir management strategy of the Al Shaheen field, offshore Qatar.

In this giant offshore oil field, the acquisition of even partial inflow production data is considered worthwhile. A production logging programme was therefore considered as essential.

A logging campaign was undertaken in twelve wells using tractor technology as means of conveyance, in a cased hole environment.

The key objectives of this campaign were to:Acquire dynamic flow data to improve the understanding of the reservoir dynamics.Identify where sub-optimum patterns can be improved to maximize ultimate recovery.Assess the tractor technology as a means of conveyance in long shallow cased horizontal wells.

The campaign showed that although static data are essential in understanding the flow performance of a well, they cannot solely always explain the flow profile along the wellbore. The acquisition of dynamic data is essential to understand the well behavior.

Results confirmed that in some long horizontal wells the flow profile takes place uniformly along the entire logged interval, whilst in others sub-optimum conditions such as cross flow and thief zones were identified. The paper describes how the data acquired helped to identify these latter conditions along with the repair opportunities to improve oil recovery.

This campaign proved that tractor is a viable means of PLT conveyance in shallow cased horizontal wells by pushing the limits of the technology to greater depths than coiled tubing – up to 14,550 ft – with less disturbance to flow. To maximize success in future well re-entries, completion design has been reviewed in new wells, in order to make them "tractor friendly".

Introduction

The Al Shaheen oil field in Block 5 and Block 5 Extension, offshore Qatar, consists of a stacked sequence of low permeability carbonate and high permeability clastic reservoirs at relatively shallow depths around 3,000 ft TVD. Although the field was discovered in the mid 1970's its development commenced decades later, in 1992, when Qatar Petroleum entered into an Exploration and Production Sharing Agreement with Maersk Oil Qatar (1). Today the Al Shaheen field produces ca. 300,000 barrels of oil per day and cumulative oil production exceeds 1.4 billion barrels.
Numerical Simulation of Natural Gas Transport in Shale Formation Using Generalized Lattice Boltzmann Method
Authors: Ning Yang , Jiang Yang , Qin Guan
Published: May 2016

In shale formations, natural gas flows either through nano-scale pores or fractures during production period. Darcy's law cannot effectively describe such transport phenomena due to its continuum assumption. Alternatively, kinetic-based lattice Boltzmann method (LBM) becomes a strong candidate of simulating organic-rich shale reservoir that contains a large amount of nano-scale pores. Among various LBM models, multiple-Relaxation-Time (generalized) LBM is considered as one of the most efficient models regarding its theories, selections of parameters, and numerical stability. For gas flow in a confined system, its molecular mean free path depends on not only the size of the confined system, but also the distance of gas molecules from solid walls. A large amount of natural gas is believed to be stored in extremely small organic pores, and adsorption in shale has a significant influence for gas transport in production. In this paper, we incorporated adsorption into generalized LBM model in order to capture the natural gas flow in organic nano-pores. Many factors are believed to control the flow mechanism in such pores, such as the size of organic pores, specific surface area, adsorptive strength, and so on. Generalized LBM results shows a great agreement with available data for high Knudsen flows between two-dimensional parallel plates. Accounted the effect of adsorption, flow phenomena are investigated by varying different controlling factors in both simple and complex structures.

Introduction

Shale gas has been becoming a significant source of unconventional natural gas. The production of shale gas mainly depends on its characteristics, such as the pore distribution, organic richness, natural/factitious fractures, etc. A significant portion of shale gas is stored in kerogen pores that are ranging 2nm to 50 nm [1, 2, 3]. Consequently, it is essential to understand natural gas flow in nanopores to be able to predict long-term shale gas production as well as shale gas reserves.
How to Improve Efficiency in Multiple History Matching: A Gas Field Case Study
Authors: Bouzarkouna Zyed , Verdiere Sophie , Jaulneau Patrice , Le Reun Juliette , Corpel Vincent
Published: May 2016

This paper proposes an innovative integrated workflow based on advanced history matching techniques for finding multiple history-matched models.

The proposed workflow is demonstrated on a condensate gas field. The deltaic depositional environment enhanced by normal faults created strong vertical and horizontal heterogeneities. This compartmentalization, added to the production in commingle, makes the history match particularly difficult. The proposed workflow begins by an intensive dynamic synthesis and a multidisciplinary teamwork definition of the objects to match (production rates, RFT, MDT, PLT). The potentially influent parameters and the associated ranges of uncertainty are also defined.

Early cooperation is crucial, as it sets up the scope of the history match strategy. This meticulous synthesis of static and dynamic observations enables to build the geological model and the associated history match strategy. Then, the following steps are performed:Screening: experimental design is used to highlight the most impacting parameters. Given the ranges of uncertainty defined in the synthesis, this step allows the reduction of uncertain parameters (32 in our case) to the most influential ones (13 parameters);Modeling: an innovative space filling design technique is used to define a limited number of simulations using only key uncertain parameters;Objective function formulation: different formulations are proposed to evaluate the history match quality;Assisted history matching: Proxy modeling is introduced in the framework of the objective function minimization and multiple history-matched models are obtained and then validated by the team.

Results on this field case show the necessity of a strong and coherent dynamic synthesis. The proposed workflow enables to evaluate the different impacting parameters of the model and thus finding different history-matched models. Provided physics and geology are clearly understood, this assisted history match technique is highly helpful in particular for complex fields with a large amount of data to match.

Introduction

History matching is defined as the process of adjusting a reservoir model until it closely reproduces the past behavior of the reservoir. This process is by nature an ill-posed inverse problem and thus there may be multiple different models that can all be valid. Multiple history-matched models are crucial for having valid estimations of the reservoir performance uncertainties and thus obtaining reliable predictions. However, in many history match studies, the first found history-matched model is accepted due to the tedious and time-consuming nature of the task.

History matching studies are then usually (in particular for complex reservoirs) very challenging and require an important cooperation within a multidisciplinary team including reservoir engineers, geologists and geophysicists.
An Integrated Subsurface Approach to Reveal Reservoir Connectivity for a Mature Field
Authors: Ng Khaiyi , Abdou Ali Asem Mahmoud , Hanalim Linda , Suwarlan Wahyudin , Lee ChunRhen
Published: May 2016

Reservoir compartments are segments that are effectively isolated by structural, sedimentologic or diagenetic barriers that hinder fluid flow laterally between compartments. However, in cases of sandstone reservoirs incising each other, the boundaries of the compartments are poorly defined and huge uncertainties are imposed on the connectivity and fluid flow behavior between them. Various geological and engineering approaches are used to work out the sand-to-sand juxtaposed reservoir compartments in Angsi Field offshore Peninsular Malaysia.

In Angsi Field, located in the Oligo-Miocene Malay basin, the I35U and I35M sandstone reservoirs from Group-I stratigraphic unit (coastal-fluvial/deltaic lobes) provide a complicated case of areal and vertical reservoir compartments. The I35U channelized blocky sand incised into I35M mouth bar sand in some parts of the field. Mapping of the interlaced reservoir compartments of both reservoirs is based on conceptual geology, log patterns and seismic data. Although the vertical spacing of the two reservoirs is below seismic resolution, the difference in quality, thickness and fluid type have allowed seismic involvement in delineating compartments.

To verify the geological findings, multidisciplinary team seeks out various methods to resolve connectivity uncertainty between the two reservoirs. Fluid gradients supported the idea; however reservoirs fluid contacts are sometimes leveled.

Existing oil producers from both reservoirs provides reliable pressure-production data for classical reservoir engineering analysis. Production Decline Curves of both reservoirs vary significantly; seemingly controlled by internal depositional architecture of each reservoir. Depletion Plots further verify no lateral communication between the two reservoirs. Finally, Material Balance proves the understanding of communication between reservoirs; oil-in-place and reserves are aligned with geological studies.

Two successful wells drilled lately based on findings from the above approach. A representative simulation model is being built for both reservoirs, incorporating the findings, to plan for further reservoir development and management strategies.

This paper shares the geological and reservoir engineering integrated approaches to resolve the reservoir connectivity uncertainties between I35M and I35U, which could be applied in similar coastal fluvial/deltaic settings. The paper also highlights the importance of multidiscipline integration in resolving reservoirs uncertainties.
Effect of sowing time and variety on seed germination and vigour index of wheat
Authors: Shaheb Md Rayhan , Islam Md Nazmul , Rahman M Siddikur , Nessa Ashratun
Published: May 2016

Experiments were carried out in research field and laboratory of Seed Technology Division, Bangladesh Agricultural Research Institute, Gazipur during rabi season of 2008-09 and 2009-10 to find out the effect of sowing time and variety on seed germination and vigour index of wheat after harvest of the crop. There were two sets of treatments, comprising a) three dates of sowing viz. 20 November, 5 December and 20 December; and b) three varieties viz. Bijoy, Sufi and Prodip. Split plot design and complete block design were followed in field and laboratory experiments, respectively. Results revealed that the highest seed germination 93.33% was recorded in Prodip sown on 20 December, 2008 and Bijoy sown on 5 December, 2009. However, all the varieties showed more than 83% seed germination at all dates of sowing of wheat. The highest vigour indices, 1.53 and 1.41 were found in the seeds of Sufi sown on 20 November in both the years of 2008 and 2009, respectively.Bangladesh J. Agril. Res. 41(1): 127-136, March 2016
Nitrogen fixating ability of mungbean genotypes under different levels of nitrogen application
Authors: Razzaque MA , Haque MM , Karim MA , Solaiman ARM
Published: May 2016

A pot culture experiment was conducted at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur during kharif II, 2012 to evaluate the nodulation, biological nitrogen fixation and yield potential of genotypes of mungbean under varying levels of N application. There were 10 mungbean genotypes viz. IPSA 12, GK 27, IPSA 3, IPSA 5, ACC12890055, GK 63, ACC12890053, BU mug 4, BARI Mung 6 and Binamoog 5, each genotype treated with six levels of N (0, 20, 40, 60, 80 and 100 kg N ha-1) . Among the genotypes, the IPSA 12 at 40 kg N ha-1 produced the maximum number of nodules (14.54 plant-1) as well as the highest nitrogen fixation (2.684 mmol C2H4). This resulted in the highest seed yield (14.22 g plant-1). The genotype ACC12890053 recorded the lowest nodulation (6 plant-1), nitrogen fixation (1.134) and seed yield (7.33 g plant-1).Bangladesh J. Agril. Res. 41(1): 163-171, March 2016
Peste des Petits Ruminants (PPR) virus antibodies in goats and cattle of the Saint Martins Island in Bangladesh
Authors: Siddiqui MSI , Ahasan A , Islam N , Kundu P , Munshi MN , Chowdhury EH
Published: May 2016

Peste des petits ruminants (PPR) is a highly contagious acute viral disease of domestic and wild ruminants particularly goats and sheep, which causes severe economic losses. Since 1993 PPR has been endemic in goats in Bangladesh. The present study was a seroprevalence study of PPR antibodies in goats and cattle at St. Martin's Island in Bangladesh from July 2012 to June 2013. There was no previous history of Rinderpest or PPR outbreak, and no Rinderpest vaccination. Blood samples were collected from 192 goats and 132 cattle randomly. All animals were apparently healthy, and were not vaccinated against Rinderpest or PPR. Serum antibody titre (competition percentage; CP value) was determined by a commercially available c-ELISA kit. The overall seroprevalence of PPR in goats was 37.5%. No serum samples from cattle were positive. In view of the high risk of PPR, a control strategy is proposed.Bangl. vet. 2014. Vol. 31, No. 2, 55-59
The effect of GnRH analogue on the fertility of Prostaglandin F2-? induced- oestrus cows
Authors: Bhowmik SK , Alam MGS , Shamsuddin M , Khatun M
Published: May 2016

The effect of GnRH analogue (gonadorelin) was studied on the fertility of 35 postpartum anoestrus zebu cows and their crosses (Friesian, Sahiwal, Sindhi). Age (4-15 years), body weight (125-375 kg), body condition score (1.5-3; 1-5 scale), parity (1-9), postpartum intervals (4-12 months) of the cows were recorded. Oestrus was synchronized with two injections of PGF2-? analogue (Luprostinol, 15 mg) intramuscularly (i.m.) 10 days apart. The cows were divided into Group I (n = 11), Group II (n = 12) and Group III (n = 12). In Group I, 8 cows with oestrus were inseminated without gonadorelin treatment. In group II, 6 cows in oestrus were treated with gonadorelin (0.25 mg) i.m. just prior to insemination. In group III, 3 days after the second injection of luprostinol, cows with smooth ovaries were treated with gonadorelin followed by luprostinol injection 9 days later, which resulted in oestrus in 8 of the 12 cows, which were inseminated. Cows without oestrus signs were inseminated at fixed-time (72 and 96 hours after the last luprostinol injection). In group I, II and III, 5, 6 and 8 cows became pregnant, respectively (P>0.05). More cows became pregnant at observed oestrus (68.2%) than at fixed-time insemination (30.8%; P<0.05). Insemination in observed oestrus is more effective than at fixed-time. GnRH analogue may have favourable effect on the induction of oestrus by PGF2-? analogue.Bangl. vet. 2014. Vol. 31, No. 2, 60-69
Performances of commercial hybrid broiler in villages of Bangladesh
Authors: Islam F , Hossain MS , Sarker SC , Hossain MS
Published: May 2016

A total of 20 broiler farms were enumerated to evaluate the production performance of broiler birds and farm management status at rural villages of Mymensingh Sadar (district headquarters) Upazila under Mymensingh district in Bangladesh. Data were collected on day-old chick weight (DOCW), live broiler weight at market age (MW), feed conversion ratio (FCR), average daily body weight gain (ADG), mortality up to age of marketing (MTRT) during June and July, 2014 using a pre-tested questionnaire by door-to-door visit. Seventeen out of 20 farms had broiler houses with gable type roof of corrugated iron sheet (CIS), all farmers were using rice husk as litter materials and electric brooder for brooding birds for 7 days. To minimize heat stress, 65% farmers used electric fan and drinking water, and to minimize cold stress quantities of litter materials were increased and vitamin C was supplied with lukewarm drinking water. Newcastle Disease (ND) and Infectious Bursal Disease (IBD) vaccines were used by all farmers. Mean ADG, MW, DOCW and MTRT were 45.3 ± 1.2g/bird, 1581.6 ± 46.1g/bird, 54.7 ± 3.0g/bird and 5.2 ± 1.0%, respectively. Feed from two different companies had no significant effect on FCR and MTRT but feed company affected the ADG significantly. DOCW, farm size and farmers education did not affect ADG, FCR and MTRT significantly.Bangl. vet. 2014. Vol. 31, No. 2, 84-90
Does Global Justice Require More than Just Global Institutions?
Authors: Tan Kok-Chor
Published: May 2016

The ‘institutional approach’ to justice holds that persons’ responsibility of justice is primarily to support, maintain, and comply with the rules of just institutions. Within the rules of just institutions, so long as their actions do not undermine these background institutions, individuals have no further responsibilities of justice. But what does the institutional approach say in the non-ideal context where just institutions are absent, such as in the global case? One reading of the institutional approach, in this case, is that our duties are primarily to create just institutions, and that when we are doing our part in this respect, we may legitimately pursue other personal or associational ends. This ‘strong’ reading of our institutional duty takes it to be both a necessary and sufficient duty of justice of individuals that they do their part to establish just arrangements. But how plausible is this? On the one hand this requirement seems overly inflexible; on the other it seems overly lax. I clarify the motivation and context of this reading of the institutional duty, and suggest that it need not be as implausible as it seems.
Talents in the Service of Justice: Responding to Unequal Ownership beyond Compliance
Authors: Päivänsalo Ville
Published: May 2016

Over the past few decades, economic inequalities have continued to grow in most countries and the world is still lacking effective global tax schemes or corresponding structures of global distributive justice. Thus, for the world’s top-owners, simply complying with the existing rules hardly suffices as a virtue of justice. In the current article, G. A. Cohen’s nation-centered account of individual virtues in the service of distributive justice is elaborated further in a broader perspective. First, Cohen’s basic insights into the virtues of the talented rich are reconsidered under the conditions of highly unequal Western democracies in the global age as recently depicted by Thomas Piketty. Second, it is asked with reference to the Bill and Melinda Gates Foundation, if the exceptional generosity of some superrich people can serve as a proper response to the assumed deficit of justice. Third, an ethic of generous compliance is outlined as a possible mediating approach in the discussion of the responsibilities of the talented rich in an age of high economic, health, and capability inequalities as well as public sector austerity.
Effect of Islanding and Telecontrolled Switches on Distribution System Reliability Considering Load and Green-Energy Fluctuations
Authors: Conti Stefania , Faraci Giuseppe , La Corte Aurelio , Nicolosi Rosario , Rizzo Santi , Schembra Giovanni
Published: May 2016

To improve electrical distribution network reliability, some portions of the network could operate in autonomous mode, provided that the related technical issues are addressed. More specifically, when there is not a path from those portions to the primary substation due to a fault in the network, such portions could be disconnected from the main network and supplied by local generation only. Such a mode of operation is known as “intentional islanding” and its effectiveness, in terms of adequacy, depends on the ability of the local generation to meet the island’s load. In fact, the ratio between the available local generation and load demand can frequently change during islanding due to load variations and, especially, due to the strongly irregular behavior of the primary energy sources of renewable generators. This paper proposes an analytical formulation to assess local generation adequacy during intentional islanding, accounting for the aforementioned variations. More specifically, the fluctuations of load and green-energy generators during islanding are modeled by means of Markov chains, whose output quantities are encompassed in the proposed analytical formulation. Such a formulation is used by the analytical equations of load points’ outage rate and duration. The evaluation of the reliability indices accounts for a protection scheme based on an appropriate communication infrastructure. Therefore, a brief overview on the telecommunications technologies has been presented with reference to their suitability for the specific application. In particular, distribution network safety issues have been considered as the main concern. The results show that neglecting load and generation fluctuations leads to a strong overestimation of the ability of distributed generators to meet the island load. Through a case study it is observed that the error on the load point outage rate is greater than the one affecting the outage duration.
Single Cell Chemotactic Responses of Helicobacter pylori to Urea in a Microfluidic Chip
Authors: Weng Xuan , Neethirajan Suresh , Vogt Adam
Published: May 2016

Helicobacter pylori is a spiral-shaped bacterium that grows in the human digestive tract; it infects ~50% of the global population. H. pylori induce inflammation, gastroenteritis, and ulcers, which is associated with significant morbidity and may be linked to stomach cancer in certain individuals. Motility is an essential virulence factor for H. pylori, allowing it to migrate toward and invade the epithelial lining of the stomach to shelter it from the harsh environment of the stomach. H. pylori senses pH gradients and use polar flagella to move towards the epithelium where the pH approaches neutrality. However, its chemotaxis behaviors are incompletely understood. Previous in vitro tests examining the response of H. pylori to chemical gradients have been subjected to substantial limitations. To more accurately mimic/modulate the cellular microenvironment, a nanoporous microfluidic device was used to monitor the real time chemotactic activity of single cell of H. pylori in response to urea. The results showed that microfluidic method is a promising alternative for accurate studying of chemotactic behavior of H. pylori, the application of which may also be extended in the studies of other bacteria.
Immobilization of Genetically-Modified d-Amino Acid Oxidase and Catalase on Carbon Nanotubes to Improve the Catalytic Efficiency
Authors: Li Rong , Sun Jian , Fu Yaqi , Du Kun , Cai Mengsha , Ji Peijun , Feng Wei
Published: May 2016

d-amino acid oxidase (DAAO) and catalase (CAT) have been genetically modified by fusing them to an elastin-like polypeptide (ELP). ELP-DAAO and ELP-CAT have been separately immobilized on multi-walled carbon nanotubes (MWNTs). It has been found that the secondary structures of the enzymes have been preserved. ELP-DAAO catalyzed the oxidative deamination of d-alanine, and H2O2 was evolved continuously. When the MWNT-supported enzymes were used together, the generated hydrogen peroxide of ELP-DAAO could be decomposed in situ. The catalytic efficiency of the two immobilized enzymes was more than five times greater than that of free ELP-DAAO when the ratio of immobilized ELP-CAT to immobilized ELP-DAAO was larger than 1:1.
A New Method of Gold Foil Damage Detection in Stone Carving Relics Based on Multi-Temporal 3D LiDAR Point Clouds
Authors: Hou Miaole , Li Shukun , Jiang Lili , Wu Yuhua , Hu Yungang , Yang Su , Zhang Xuedong
Published: May 2016

The timely detection of gold foil damage in gold-overlaid stone carvings and the associated maintenance of these relics pose several challenges to both the research and heritage protection communities internationally. This paper presents a new method for detecting gold foil damage by making use of multi-temporal 3D LiDAR point clouds. By analyzing the errors involved in the detection process, a formula is developed for calculation of the damage detection threshold. An improved division method for the linear octree that only allocates memory to the non-blank nodes, is proposed, which improves storage and retrieval efficiency for the point clouds. Meanwhile, the damage-occurrence regions are determined according to Hausdorff distances. Using a triangular mesh, damaged regions can be identified and measured in order to determine the relic’s total damaged area. Results demonstrate that this method can effectively detect gold foil damage in stone carvings. The identified surface area of damaged regions can provide the information needed for subsequent restoration and protection of relics of this type.
Optimizing Hybrid de Novo Transcriptome Assembly and Extending Genomic Resources for Giant Freshwater Prawns (Macrobrachium rosenbergii): The Identification of Genes and Markers Associated with Reproduction
Authors: Jung Hyungtaek , Yoon Byung-Ha , Kim Woo-Jin , Kim Dong-Wook , Hurwood David , Lyons Russell , Salin Krishna , Kim Heui-Soo , Baek Ilseon , Chand Vincent , Mather Peter
Published: May 2016

The giant freshwater prawn, Macrobrachium rosenbergii, a sexually dimorphic decapod crustacean is currently the world’s most economically important cultured freshwater crustacean species. Despite its economic importance, there is currently a lack of genomic resources available for this species, and this has limited exploration of the molecular mechanisms that control the M. rosenbergii sex-differentiation system more widely in freshwater prawns. Here, we present the first hybrid transcriptome from M. rosenbergii applying RNA-Seq technologies directed at identifying genes that have potential functional roles in reproductive-related traits. A total of 13,733,210 combined raw reads (1720 Mbp) were obtained from Ion-Torrent PGM and 454 FLX. Bioinformatic analyses based on three state-of-the-art assemblers, the CLC Genomic Workbench, Trans-ABySS, and Trinity, that use single and multiple k-mer methods respectively, were used to analyse the data. The influence of multiple k-mers on assembly performance was assessed to gain insight into transcriptome assembly from short reads. After optimisation, de novo assembly resulted in 44,407 contigs with a mean length of 437 bp, and the assembled transcripts were further functionally annotated to detect single nucleotide polymorphisms and simple sequence repeat motifs. Gene expression analysis was also used to compare expression patterns from ovary and testis tissue libraries to identify genes with potential roles in reproduction and sex differentiation. The large transcript set assembled here represents the most comprehensive set of transcriptomic resources ever developed for reproduction traits in M. rosenbergii, and the large number of genetic markers predicted should constitute an invaluable resource for future genetic research studies on M. rosenbergii and can be applied more widely on other freshwater prawn species in the genus Macrobrachium.
Improved Charge Separation in WO3/CuWO4 Composite Photoanodes for Photoelectrochemical Water Oxidation
Authors: Wang Danping , Bassi Prince , Qi Huan , Zhao Xin , Gurudayal  , Wong Lydia , Xu Rong , Sritharan Thirumany , Chen Zhong
Published: May 2016

Porous tungsten oxide/copper tungstate (WO3/CuWO4) composite thin films were fabricated via a facile in situ conversion method, with a polymer templating strategy. Copper nitrate (Cu(NO3)2) solution with the copolymer surfactant Pluronic®F-127 (Sigma-Aldrich, St. Louis, MO, USA, generic name, poloxamer 407) was loaded onto WO3 substrates by programmed dip coating, followed by heat treatment in air at 550 °C. The Cu2+ reacted with the WO3 substrate to form the CuWO4 compound. The composite WO3/CuWO4 thin films demonstrated improved photoelectrochemical (PEC) performance over WO3 and CuWO4 single phase photoanodes. The factors of light absorption and charge separation efficiency of the composite and two single phase films were investigated to understand the reasons for the PEC enhancement of WO3/CuWO4 composite thin films. The photocurrent was generated from water splitting as confirmed by hydrogen and oxygen gas evolution, and Faradic efficiency was calculated based on the amount of H2 produced. This work provides a low-cost and controllable method to prepare WO3-metal tungstate composite thin films, and also helps to deepen the understanding of charge transfer in WO3/CuWO4 heterojunction.
Characteristics of Carbon Material Formation on SBA-15 and Ni-SBA-15 Templates by Acetylene Decomposition and Their Bioactivity Effects
Authors: Chiang Hsiu-Mei , Cho Kuan-Yu , Zeng Li-Xuan , Chiang Hung-Lung
Published: May 2016

Carbon spheres and tubes were formed from acetylene decomposition on SBA-15 and Ni-SBA-15 at 650–850 °C. At 650 °C, the decomposed carbons covered the surface of the support, and no carbon spheres and filament materials were formed. Carbon sphere formation occurred at 750 °C–850 °C; with diameters ranging from 0.8 μm–1.1 μm. For Ni-SBA-15, the diameters of the spheres and filaments were 0.8 μm and 62 nm, respectively, at 650 °C. At 750 °C, the diameter of the ball carbon materials ranged from 0.7 μm–0.8 μm, the diameter of the carbon tubes formed was 120–130 nm, and their pore diameter was 8.0 nm–11 nm. At 850 °C, the diameters of ball carbon materials and carbon tubes were similar to those of the materials at the formation temperature, 750 °C. Si, O and C were the main constituents of SBA-15; Ni-SBA-15 and carbon material formation supports. High-ring PAHs (such as BaP (five rings); IND (six rings); DBA (five rings) and B[ghi]P (six rings)) exist in carbon materials. SBA-15 revealed insignificant cytotoxicity, but Ni-SBA-15 inhibited the proliferation of human lung cancer cells (A549). Less inhibition on cell viability and reactive oxidative species (ROS) generation on A549 were determined for carbon material formation on the Ni-SBA-15 compared to the Ni-SBA-15.
Effect of Graphene Nanoplatelets on the Physical and Antimicrobial Properties of Biopolymer-Based Nanocomposites
Authors: Scaffaro Roberto , Botta Luigi , Maio Andrea , Mistretta Maria , La Mantia Francesco
Published: May 2016

In this work, biopolymer-based nanocomposites with antimicrobial properties were prepared via melt-compounding. In particular, graphene nanoplatelets (GnPs) as fillers and an antibiotic, i.e., ciprofloxacin (CFX), as biocide were incorporated in a commercial biodegradable polymer blend of poly(lactic acid) (PLA) and a copolyester (BioFlex®). The prepared materials were characterized by scanning electron microscopy (SEM), and rheological and mechanical measurements. Moreover, the effect of GnPs on the antimicrobial properties and release kinetics of CFX was evaluated. The results indicated that the incorporation of GnPs increased the stiffness of the biopolymeric matrix and allowed for the tuning of the release of CFX without hindering the antimicrobial activity of the obtained materials.
Rapamycin Loaded Solid Lipid Nanoparticles as a New Tool to Deliver mTOR Inhibitors: Formulation and in Vitro Characterization
Authors: Polchi Alice , Magini Alessandro , Mazuryk Jarosław , Tancini Brunella , Gapiński Jacek , Patkowski Adam , Giovagnoli Stefano , Emiliani Carla
Published: May 2016

Recently, the use of mammalian target of rapamycin (mTOR) inhibitors, in particular rapamycin (Rp), has been suggested to improve the treatment of neurodegenerative diseases. However, as Rp is a strong immunosuppressant, specific delivery to the brain has been postulated to avoid systemic exposure. In this work, we fabricated new Rp loaded solid lipid nanoparticles (Rp-SLN) stabilized with polysorbate 80 (PS80), comparing two different methods and lipids. The formulations were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), wide angle X-ray scattering (WAXS), cryo-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS) and particle tracking. In vitro release and short-term stability were assessed. Biological behavior of Rp-SLN was tested in SH-SY5Y neuroblastoma cells. The inhibition of mTOR complex 1 (mTORC1) was evaluated over time by a pulse-chase study compared to free Rp and Rp nanocrystals. Compritol Rp-SLN resulted more stable and possessing proper size and surface properties with respect to cetyl palmitate Rp-SLN. Rapamycin was entrapped in an amorphous form in the solid lipid matrix that showed partial crystallinity with stable Lβ, sub-Lα and Lβ′ arrangements. PS80 was stably anchored on particle surface. No drug release was observed over 24 h and Rp-SLN had a higher cell uptake and a more sustained effect over a week. The mTORC1 inhibition was higher with Rp-SLN. Overall, compritol Rp-SLN show suitable characteristics and stability to be considered for further investigation as Rp brain delivery system.
Sesamin Ameliorates High-Fat Diet–Induced Dyslipidemia and Kidney Injury by Reducing Oxidative Stress
Authors: Zhang Ruijuan , Yu Yan , Deng Jianjun , Zhang Chao , Zhang Jinghua , Cheng Yue , Luo Xiaoqin , Han Bei , Yang Haixia
Published: May 2016

The study explored the protective effect of sesamin against lipid-induced renal injury and hyperlipidemia in a rat model. An animal model of hyperlipidemia was established in Sprague-Dawley rats. Fifty-five adult Sprague-Dawley rats were divided into five groups. The control group was fed a standard diet, while the other four groups were fed a high-fat diet for 5 weeks to induce hyperlipidemia. Three groups received oral sesamin in doses of 40, 80, or 160 mg/(kg·day). Seven weeks later, the blood lipids, renal function, antioxidant enzyme activities, and hyperoxide levels in kidney tissues were measured. The renal pathological changes and expression levels of collagen type IV (Col-IV) and α-smooth muscle actin (α-SMA) were analyzed. The administration of sesamin improved the serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, apolipoprotein-B, oxidized-low-density lipoprotein, and serum creatinine levels in hyperlipidemic rats, while it increased the high-density lipoprotein cholesterol and apolipoprotein-A levels. Sesamin reduced the excretion of 24-h urinary protein and urinary albumin and downregulated α-SMA and Col-IV expression. Moreover, sesamin ameliorated the superoxide dismutase activity and reduced malondialdehyde levels in kidney tissue. Sesamin could mediate lipid metabolism and ameliorate renal injury caused by lipid metabolism disorders in a rat model of hyperlipidemia.
InSAR-Based Mapping of Tidal Inundation Extent and Amplitude in Louisiana Coastal Wetlands
Authors: Oliver-Cabrera Talib , Wdowinski Shimon
Published: May 2016

The Louisiana coast is among the most productive coastal areas in the US and home to the largest coastal wetland area in the nation. However, Louisiana coastal wetlands have been disappearing at an alarming rate due to natural and anthropogenic processes, including sea level rise, land subsidence and infrastructure development. Wetland loss occurs mainly along the tidal zone, which varies in width and morphology along the Louisiana shoreline. In this study, we use Interferometric Synthetic Aperture Radar (InSAR) observations to detect the extent of the tidal inundation zone and evaluate the interaction between tidal currents and coastal wetlands. Our data consist of ALOS and Radarsat-1 observations acquired between 2006–2011 and 2003–2008, respectively. Interferometric processing of the data provides detailed maps of water level changes in the tidal zone, which are validated using sea level data from a tide gauge station. Our results indicate vertical tidal changes up to 30 cm and horizontal tidal flow limited to 5–15 km from open waters. The results also show that the tidal inundation is disrupted by various man-made structures, such as canals and roads, which change the natural tidal flow interaction with the coast.
Quantitative Index and Abnormal Alarm Strategy Using Sensor-Dependent Vibration Data for Blade Crack Identification in Centrifugal Booster Fans
Authors: Chen Jinglong , Sun Hailiang , Wang Shuai , He Zhengjia
Published: May 2016

Centrifugal booster fans are important equipment used to recover blast furnace gas (BFG) for generating electricity, but blade crack faults (BCFs) in centrifugal booster fans can lead to unscheduled breakdowns and potentially serious accidents, so in this work quantitative fault identification and an abnormal alarm strategy based on acquired historical sensor-dependent vibration data is proposed for implementing condition-based maintenance for this type of equipment. Firstly, three group dependent sensors are installed to acquire running condition data. Then a discrete spectrum interpolation method and short time Fourier transform (STFT) are applied to preliminarily identify the running data in the sensor-dependent vibration data. As a result a quantitative identification and abnormal alarm strategy based on compound indexes including the largest Lyapunov exponent and relative energy ratio at the second harmonic frequency component is proposed. Then for validation the proposed blade crack quantitative identification and abnormality alarm strategy is applied to analyze acquired experimental data for centrifugal booster fans and it has successfully identified incipient blade crack faults. In addition, the related mathematical modelling work is also introduced to investigate the effects of mistuning and cracks on the vibration features of centrifugal impellers and to explore effective techniques for crack detection.