bluuebunny/crossref_metadata_2025 huggingface dataset:
Production Enhancement by Customised Hydraulic Fracturing Operations: Success Stories of Gamij Field
Authors: Medavarapu Kishore Kumar , Mahato P K , Das Santanu , Singh S K , Patel K C , Nandan Alok
Published: March 2012

Customized hydraulic fracturing operations in low temperature and shallow reservoirs of Gamij field of western onshore India yielded impressive post frac production gains. This paper describes in detail, the various challenges for hydraulic fracturing in Gamij field, development of fracturing fluid, execution methodology and fracturing’s vital role in production enhancement.

Successful hydraulic fracturing operations turned Gamij as one of the promising producing field. Poor reservoir characteristics, thin pay zones, presence of coal layers, shallow depths and low reservoir temperatures were the main challenges for hydraulic fracturing. Numerous lab studies carried out and fracturing fluids were customized for good rheological capabilities and postfrac gel cleanups. Frac job sizes were optimized based on sensitivity analysis carried out using frac simulators. Large size jobs were carried out in suitable candidate wells. Pre and Post frac temperature logs were taken to ascertain the fluid intake and frac confinements. Activation methodologies developed so as to bring the wells on production in minimum time.

Hydraulic fracturing jobs in Gamij field were quite successful. Fracturing jobs were carried out in 35 wells in the last two years mostly with drilling rig in position. Most of the wells came on self. Oil production up to 30m3/d in a single well was observed. Job sizes were designed based on reservoir characteristics which ranged from 60000 lb to 242500 lb. 20/40 low strength proppant pumped in these frac jobs with maximum concentration of 15 ppg. Job scheduling varied based on thickness of payzones, behavior of nearby coal layers. Temperature logs showed a good placement of proppant in target zones which helped in getting impressive post frac productions. The results of frac jobs turned this small field into one of the most promising fields in the area.

Customized hydraulic fracturing helped in the enhancing the production from ageing & mature western onshore oil fields of India. Success of fracturing campaign in Gamij field led to augmented drilling activity in similar pay zones to extract hydrocarbons and support the increasing energy demand. This strategic hydraulic fracturing methodology customized for other fields in the region which were also proved quite successful.
Application of Analytical Technique for Streamline and Flood-front Mapping in Giant Offshore Carbonate Reservoir
Authors: Nautiyal D. K. , Jain P. K. , Lohar B. L. , Marathe R. V.
Published: March 2012

A giant multi-layered carbonate reservoir in offshore India is undergoing water-flooding since 1987. Historically there have been about 930 producer and 250 injection strings in the field with about half of them active today. In order to have quick flood surveillance, flow streamline snapshots and flood-front maps have been attempted using in-house developed analytical technique assuming homogeneous, incompressible, unit mobility ratio displacement process.

The eleven producing unit of the reservoir are clubbed as five major stacks for streamline generation. Injection and production volumes are divided among these five stacks on the basis of existing history matched simulation model. The volumes are then normalized to obtain the relative strengths of the producers and injectors Macro level reservoir anisotropy is inherently taken care by the normalization process of rates. Reservoir boundary for each stack is simulated by placing large number of image wells along each boundary. The velocity and potential distribution in the reservoir are obtained using the principle of superposition. The velocity equation tracks the path of the fluid particle generating the flow streamlines.

Flood-front positions are generated by repeating the above process. The field water cut vs. pore volume of water injected is compared against the actual water cut vs. pore volume of water injected as a history matching process. Individual well water-cut are then superposed on the flood-front positions in the corresponding stack.

Flood front positions are corroborated to a large extent with the superposed water-cut in individual wells. Deviations in the actual water-cut trend are also observed in few areas. Recommendations for redistribution of injected water among the identified stacks are presented on a holistic basis to achieve better sweep efficiency in the reservoir and field trials are awaited.

The attempt is to use this fast and simple analytical technique on a desktop computer for quick water-flood surveillance of a large field.
Optimising Exploitation Strategy of Multi layered Reservoir for higher recovery – A Case Study of an Aging Field, Cambay Basin, India
Authors: Dubey Prashant K , Mishra Pranav K , Walia Ashok , Lohiya J. P.
Published: March 2012

The HC field was discovered in 1972 and put on commercial production in 1974. The field’s oil production reached life-time high of 461 tpd (tonnes per day) in June, 2006. However, soon the production started declining, rather rapidly, and average production during 2009-2010 was mere 220 tpd, which necessitated an integrated review of the field, combining geosciences, reservoir engineering and production technology. Study started with organizing abundant and scattered field data, recording of Cased Hole Formation Resistivity (CHFR) / Reservoir Monitoring Tool (RMT) and Cased Hole Compensated Neutron (C/H CNL) logs in key wells, which tagged shifted fluid contacts and modified saturations. Past performance of the sands was studied and reservoir simulation carried out for obtaining suitable perforation policy for sands with GOC and OWC. Shale/coal barriers were identified and their reliability was tested for two reservoir units, which helped in putting the rim of oil between GOC and OWC on production. Based on the integrated study, opportunities were identified and well interventions through work-over jobs were carried out for recompletion, zone transfer and water shut-off. Geology of the main block was redefined integrating seismic and new data gathered from four strategically newly drilled wells.

Further, a strategy was firmed up for rational exploitation of all sands in the multi-layered block aiming at maximising recovery and minimizing development and operating cost. Implementation of the study augmented field’s production to a second plateau with increase in production from 220 tpd to 375 tpd.
Simulation of In-Situ Combustion Process in Balol Pilot
Authors: Dayal H. S. , Bhushan B. V. , Mitra Sujit , Pandey Vivek , Bhandari A. C. , Dwivedi M. M.
Published: March 2012

The In-situ Combustion (ISC) process has been successfully applied in the Southern part of Balol field for the last 21 years. This sector has oil of 300 cp viscosity and 15° API. The Pilot was initiated in 1990 followed by semi-commercialization in 1992 and commercialization in 1997. It has been instrumental in enhancing the oil recovery from 13% to 50%. The ISC process in the pilot stage has been modeled on the thermal simulator. At first, the 1-D Combustion tube experiment has been successfully modeled and history matched with single equation incorporating the oxidation of heavy oil. The reaction kinetics from Combustion tube model with suitable modification and the Equilibrium Constants obtained from the Equation of State (EOS) modeling of PVT experiments has been utilised to history match the ISC pilot performance.

The ISC model calibrated from the history match of the actual data of the pilot shall enable in simulating the ISC process in the semi-commercial and the commercial phase. It would help in optimization of air injection rates, placement of air injectors, propagation of the combustion front, performance prediction and finally the ultimate recovery.

The successful history match of the ISC process in the Pilot area in terms of water cut, liquid rates has enabled better understanding of the process. It was possible to obtain a good agreement for the propagation of the combustion front and the temperature distribution.

The study has indicated that the ISC simulation on thermal simulator using single equation can be used as significant stepping stone in modeling the process in more detail using multiple equations and incorporating larger area.
Unlocking Potential of Offshore Marginal Fields in India: A Success Story
Authors: Nischal Rajiv , Kumar Adesh , Vasudeva Sudhir
Published: March 2012

Marginal field refers to a field which due to various factors (geologic, geographic, technological or economic) may not produce enough net income to make it worth developing at a given time. However; should technical or economic conditions change, such a field may become commercially viable. It is usually associated with small pockets of hydrocarbons that have a plateau of a few years.

Currently, ONGC has more than 165 such small and marginal fields totaling reserves of more 297 MMT. Most of these are far away from existing infrastructures, located at great water depths or contain insufficient reserves distributed in multiple pays to consider development on a stand-alone basis. Concerted efforts involving complex combination and integration of human resources, advanced technologies improving scale of economies by integrated cluster development and changed economic scenario, many of these fields could be made economically feasible. This led to monetization of 53 fields till date and 69 fields are under various stages of monetization.

The paper illustrates through case histories the approach followed for the integrated development of these marginal fields in offshore, with special emphasis on: - grouping of marginal fields with economic fields, cluster development, modularization and standardization of process facilities/wells for optimizing cost, revamping existing jack-ups as mobile processing, CAPEX reduction through hired FPSO and use of advanced techniques like multilaterals, dual completions, zones transfers etc.

Due to these initiatives, oil production for ONGC’s offshore marginal fields is expected to peak at about 1,25,000 bopd and gas production will peak at about 17 MMm3/d in 2014-15.
Case Study: Asia Pacific First Ever Closing of a Fluid-loss Isolation Valve Using Electric Line in a Highly Deviated Well
Authors: Dzul-Fikar Muhamad Nasri
Published: March 2012

An offshore operator in Malaysia detected an unexplained annulus pressure increase after completing a large-bore gas production well. A leak detection tool was run on an electric line tractor and located leaking tubing connections at 333 m and 394 m MD. This led the operator to recomplete the well.

The operator chose to close a fluid loss isolation valve at 1800 m MD. Because an electric line tractor, hydraulic stroking tool, and key tool were already onboard the platform as a contingency to open the valve, this suit of technology was chosen to close the valve.

The toolstring was configured with a 4.625" key pad to fit into the sliding sleeve of the valve and run in the hole. The tractor was activated 146 m above the valve and then driven down to the valve where a depth correlation was made. Then the toolstring was placed with the key extended until it reached the recess area above the shifting profile. The piston of the hydraulic stroker was extended with the key pads expanded and located the shifting profile. Next, the hydraulic stroker was activated to stroke up and thereby closed the ball valve.

The valve was closed in 15 hours from rig up to rig down, including 2 hours of inflow test. This was the first time such a valve has been closed on electric line in Asia Pacific and the operation proved the viability and efficiency of the technology. Importantly, the operator did not kill the well and saved significant costs by cutting the time in half compared to a workover.

This paper will present the learning from the operation while discussing this newly adopted approach and the benefits it offers to the industry.
Combination of Dual String Single Trip Multi-Zone Completion Systems and High Rate Formation Pack as a Proven Completion Methodology for an Unconsolidated Reservoir: Case Study Tunu Field
Authors: Laidlaw D. , Agee D. , Madyanova M. , Hustache H.
Published: March 2012

Failures due to sand production can manifest themselves in many ways; from surface equipment damage to downhole equipment failures which can ultimately result in loss of well integrity and worst case catastrophic failure. Several methods are available in the industry to control sand production problems, gravel packing being a widely used method. Gravel packing entails placing a sand or proppant filter in the annular space between an unconsolidated formation and a centralized slotted liner or wire-wrapped screen. Increased mechanical skin and achieving time and cost efficiencies are amongst the many challenges faced when implementing gravel packs as part of a completion operation.

The Tunu field is a large gas field located in the Mahakam delta, East Kalimantan, Indonesia. Gas production started in 1990 and to date hundreds of wells have been drilled in the field. Until recently, the primary target was the Tunu Main formation which is a deep, well consolidated reservoir. To maintain production goals the operator has started to produce from the shallower unconsolidated zones. The first well targeting the Tunu Shallow reservoir was drilled in 2008. The Tunu Shallow formation has average porosity of 28% and permeability of approximately 1 Darcy. Shale content can be as high as 25%. Coal seams are also frequently found interbedded amongst the shales and reservoir sands. Within the interval of 500 to 2,000 m TVD the reservoir is generally found to be completely unconsolidated.

In the Tunu Shallow development, more than 100 zones in 30 wells have been completed using a dual string single trip multi zone gravel pack completion system (STMZ) in combination with high rate formation packing (HRFP) as the sand control method. Using these combined techniques has given excellent results in terms of well productivity, rig non-productive time (NPT) and costs. Analysis performed on data garnered from pressure build-up tests (PBU’s) show mechanical skins ranging from 10 to 21 with an average of 14 obtained. The wells produce up to 24 MMscf/D sand free. This paper explains the implementation and optimization of the STMZ completion system with HRFP treatments as a completion technique in the shallow sands of the Tunu field.
Failure Analysis of An Onshore Pipeline in Petroleum Industry – A Case Study
Authors: Talukdar Maushumi Kakoti , Kujur Abhay , Bhat S. , Sahota S. K.
Published: March 2012

The premature failure of an onshore underground well fluid line led to a fatal fire incident. Though there is no reduction in overall thickness localized internal corrosion were noticed at both 6 O’ clock and 12 O’ clock position. In some localized area near the weld there is heavy metal loss leading to formation of holes at 6 O’ clock position

Results of various laboratory investigations confirm that the corrosion and premature failure of pipeline sample was caused by localised corrosion attack. The calculation of flow regime confirms that the flow is stratified and software analysis shows that deposition of water is throughout the whole length of the pipeline thereby creating an ideal condition for deposition and growth of bacteria colony. Two different corrosion mechanisms namely microbial induced corrosion and localized corrosion of chloride have acted together and resulted in the severe attack at 6 O’ clock position. With MIC being the most pronounced. The condensed water and acid gases have caused localized corrosion often called top line corrosion at 12 O’ clock position. Therefore the flow condition, presence of high concentration of chloride and bacterial activity has acted in synergy to cause this failure of the pipeline.
Offshore Drilling & Well Testing Of A HPHT Gas Well: A Case Study
Authors: Shah Prerak H , Pandya Harsh T , Sharma Harsh , Saxena Arpit
Published: March 2012

With exploration in harsh environments and consequent high pressure and temperature conditions, the calculation of reservoir properties has become complex and thus the changes in pressure transient response need to be understood and appreciated by taking appropriate challenging measures.

The paper deals with the various challenges arising when dealing with the drilling and testing of HPHT gas wells with Hydrogen sulfide and Carbon dioxide, located in Krishna Godavari (KG) Basin and the difficulties faced while executing it. The paper focuses on the experience while drilling the reservoir with a different mud program and mechanical failure caused by HPHT conditions & highly corrosive environment. The paper also highlights the preference of SOBM over WBM while drilling the reservoir section. It also describes the learning process as the exploratory well campaign progresses from one well to other. It briefs about the challenges while performing MDT as per the program in these high temperature environment. The paper briefs about the decision involved in selection of proper grade tubing, elastomer, packer, flowhead equipments, DST tools & explosives in this HPHT environment along with Hydrogen sulfide & Carbon Dioxide. In any gas well testing, exhaustive amount of data over the requisite period of time are necessary; data redundancy necessitates redressing of equipments. The biggest challenges faced by industry are high temperature rather than high pressures, so making metallurgy an important basis of consideration. It also highlights about the method followed during correlation of prospective zones using different logs.

The paper discusses the unexpected results and observations obtained during execution of our program and the lessons learnt from it.
How Real-Time Surveillance Improves the ESP Run Life, Uptime and Reduces Production Deferment
Authors: Abdel-Basset Mohamed , Elbarkatawy Aied , Elsherif Mamdouh , Eraky Hesham , Matar Hossam , Hashim Sameh
Published: March 2012

This paper explains how the real-time surveillance helps improving runlife, uptime and reducing production deferment of Electrical Submergible Pumps (ESP) of SG-300 offshore platform wells of Gulf of Suez Petroleum Company (GUPCO). The implementation of a robust suerveillance workflow together with real-time surveillance and alarm notification system has shown a good contribution to increase ESP runlife via preventing the ESP from being misoperated outside its recommended operating conditions and experiencing excessive stress, reduce start/stops and downtime, reduce production deferment, and improve downhole chemical injection program for scale inhibition. This is being done via classification of alarms and on-fly diagnostics of main root causes that helps to promptly identify remedial actions and/or recommendations.
Resolving a Permeabilty Mismatch in a Mature Carbonate Field
Authors: Oates Michael , Mishra Gaurav , Sultana Nazneen , Nath Gitashree
Published: March 2012

A close scrutiny of core data from a producing carbonate field resolved an apparent difference between permeability evident from core plug analysis and from testing of wells in the field. This was attributed to a bias inherent in the data collection, particularly as the samping techniques avoided the most permeable features. Instead of invoking a pervasive fracture network in the static geological model, which might compromise a planned water injection campaign, it is now evident that the permeability mismatch can be satisfactorily modeled with a horizontal multiplier, and that water injection should result in a significant increase in ultimate oil recovery.
Further Evaluation of Fluoride Dating by Ion Selective Electrode Analysis
Authors: Tankersley Kenneth B. , Wells Dean H.
Published: March 2012

Fluoride dating by ion selective electrode (ISE) analysis is a viable relative dating technique for dense cortical bone from archaeological sites. The fluoride content of cortical bone and rate of absorption is directly related to the porosity and microstructure of the sample and post-depositional environmental variables including the CaF2 content of the bedrock, soil, and changes in groundwater levels, flow rates, and chemical composition. Dense diaphyseal cortical bone from homogenous sediment contexts exposed to consistent groundwater chemistry through time is the best sample for fluoride dating by the ISE technique. Teeth should not be used as samples for fluoride dating because differences in the porosity and permeability of enamel can produce wide variations in composition.
Model of the nonlinear reaction system with autocatalysis and autoinhibition: Stability of dynamic states
Authors: Macesic Stevan , Cupic Zeljko , Kolar-Anic Ljiljana
Published: March 2012

Self-regulation, achieved through positive (autocatalytic) or negative
(autoinhibitory) feedback is commonly encountered in natural, technological
and economic systems. The dynamic behavior of such systems is often complex
and cannot be easily predicted, necessitating mathematical modelling and
theoretical analyses. The aim of this work is to analyze the dynamics of a
minimal model system with autocatalytic and autoinhibitory steps coupled
through the same species, in order to understand under which critical
condition the system loses stability and passes through an Andronov-Hopf
bifurcation. The analysis used was improved stoichiometric network analysis
(SNA) in combination with bifurcation and sensitivity analysis.
Entrepreneurial Attitudes in a Post-Communist Transitional Rural Economy: The Case of Moldova
Authors: O'Brien David , Españo Eloi , Grigsby Mary , Patsiorkovsky Valery
Published: March 2012

Entrepreneurial Attitudes in a Post-Communist Transitional Rural Economy: The Case of Moldova

A sample survey of small and medium-sized farms in Moldova is used to examine the prevalence of different aspects of an "entrepreneurial outlook" in a post-communist transitional economy. Within the range of less than 1 to 100 hectare farms, the most pronounced differences are that operators of larger farms have greater "technical knowledge" of different aspects of high value agricultural production and sales as well as having a greater willingness to deal with "uncertainty and debt."
Contributions to the Knowledge on Staphylinids (Coleoptera: Staphylinidae) in Some Riparian Ecosystems of South-Eastern Romania
Authors: Stan Melania
Published: March 2012

Contributions to the Knowledge on Staphylinids (Coleoptera: Staphylinidae) in Some Riparian Ecosystems of South-Eastern Romania

The diversity of the staphylinid fauna is investigated in some riparian ecosystems along rivers of south-east Romania: the Danube, Prut, Siret, Buzău. 94 staphylinid species and subspecies were identified from 23 investigated sites. Thecturota marchii (Dodero) is a new record for the Romanian fauna. Leptobium dimidiatum (Grideli), a rare species, is recorded from a new site, the second record from Romania.
Termite-Susceptible Species of Wood for Inclusion as a Reference in Indonesian Standardized Laboratory Testing
Authors: Arinana  , Tsunoda Kunio , Herliyana Elis N. , Hadi Yusuf S.
Published: March 2012

Standardized laboratory testing of wood and wood-based products against subterranean termites in Indonesia (SNI 01.7207-2006) (SNI) has no requirement for the inclusion of a comparative reference species of wood (reference control). This is considered a weakness of the Indonesian standard. Consequently, a study was undertaken to identify a suitable Indonesian species of community wood that could be used as a reference control. Four candidate species of community woods: Acacia mangium, Hevea brasiliensis, Paraserianthes falcataria and Pinus merkusii were selected for testing their susceptibility to feeding by Coptotermes formosanus. Two testing methods (SNI and the Japanese standard method JIS K 1571-2004) were used to compare the susceptibility of each species of wood. Included in the study was Cryptomeria japonica, the reference control specified in the Japanese standard. The results of the study indicated that P. merkusii is a suitable reference species of wood for inclusion in laboratory tests against subterranean termites, conducted in accordance with the Indonesian standard (SNI 01.7207-2006).
A Lactose-Binding Lectin from the Marine Sponge Cinachyrella Apion (Cal) Induces Cell Death in Human Cervical Adenocarcinoma Cells
Authors: Rabelo Luciana , Monteiro Norberto , Serquiz Raphael , Santos Paula , Oliveira Ruth , Oliveira Adeliana , Rocha Hugo , Morais Ana Heloneida , Uchoa Adriana , Santos Elizeu
Published: March 2012

Cancer represents a set of more than 100 diseases, including malignant tumors from different locations. Strategies inducing differentiation have had limited success in the treatment of established cancers. Marine sponges are a biological reservoir of bioactive molecules, especially lectins. Several animal and plant lectins were purified with antitumor activity, mitogenic, anti-inflammatory and antiviral, but there are few reports in the literature describing the mechanism of action of lectins purified from marine sponges to induce apoptosis in human tumor cells. In this work, a lectin purified from the marine sponge Cinachyrella apion (CaL) was evaluated with respect to its hemolytic, cytotoxic and antiproliferative properties, besides the ability to induce cell death in tumor cells. The antiproliferative activity of CaL was tested against HeLa, PC3 and 3T3 cell lines, with highest growth inhibition for HeLa, reducing cell growth at a dose dependent manner (0.5–10 µg/mL). Hemolytic activity and toxicity against peripheral blood cells were tested using the concentration of IC50 (10 µg/mL) for both trials and twice the IC50 for analysis in flow cytometry, indicating that CaL is not toxic to these cells. To assess the mechanism of cell death caused by CaL in HeLa cells, we performed flow cytometry and western blotting. Results showed that lectin probably induces cell death by apoptosis activation by pro-apoptotic protein Bax, promoting mitochondrial membrane permeabilization, cell cycle arrest in S phase and acting as both dependent and/or independent of caspases pathway. These results indicate the potential of CaL in studies of medicine for treating cancer.
Diatom Derived Polyunsaturated Aldehydes Do Not Structure the Planktonic Microbial Community in a Mesocosm Study
Authors: Paul Carsten , Reunamo Anna , Lindehoff Elin , Bergkvist Johanna , Mausz Michaela A. , Larsson Henrik , Richter Hannes , Wängberg Sten-Åke , Leskinen Piia , Båmstedt Ulf , Pohnert Georg
Published: March 2012

Several marine and freshwater diatoms produce polyunsaturated aldehydes (PUA) in wound-activated processes. These metabolites are also released by intact diatom cells during algal blooms. Due to their activity in laboratory experiments, PUA are considered as potential mediators of diatom-bacteria interactions. Here, we tested the hypothesis that PUA mediate such processes in a close-to-field mesocosm experiment. Natural plankton communities enriched with Skeletonema marinoi strains that differ in their PUA production, a plankton control, and a plankton control supplemented with PUA at natural and elevated concentrations were observed. We monitored bacterial and viral abundance as well as bacterial community composition and did not observe any influence of PUA on these parameters even at elevated concentrations. We rather detected an alternation of the bacterial diversity over time and differences between the two S. marinoi strains, indicating unique dynamic bacterial communities in these algal blooms. These results suggest that factors other than PUA are of significance for interactions between diatoms and bacteria.
Spatial Heterogeneity of Autoinducer Regulation Systems
Authors: Hense Burkhard A. , Müller Johannes , Kuttler Christina , Hartmann Anton
Published: March 2012

Autoinducer signals enable coordinated behaviour of bacterial populations, a phenomenon originally described as quorum sensing. Autoinducer systems are often controlled by environmental substances as nutrients or secondary metabolites (signals) from neighbouring organisms. In cell aggregates and biofilms gradients of signals and environmental substances emerge. Mathematical modelling is used to analyse the functioning of the system. We find that the autoinducer regulation network generates spatially heterogeneous behaviour, up to a kind of multicellularity-like division of work, especially under nutrient-controlled conditions. A hybrid push/pull concept is proposed to explain the ecological function. The analysis allows to explain hitherto seemingly contradicting experimental findings.
A Real-Time Measurement System for Long-Life Flood Monitoring and Warning Applications
Authors: Marin-Perez Rafael , García-Pintado Javier , Gómez Antonio Skarmeta
Published: March 2012

A flood warning system incorporates telemetered rainfall and flow/water level data measured at various locations in the catchment area. Real-time accurate data collection is required for this use, and sensor networks improve the system capabilities. However, existing sensor nodes struggle to satisfy the hydrological requirements in terms of autonomy, sensor hardware compatibility, reliability and long-range communication. We describe the design and development of a real-time measurement system for flood monitoring, and its deployment in a flash-flood prone 650 km2 semiarid watershed in Southern Spain. A developed low-power and long-range communication device, so-called DatalogV1, provides automatic data gathering and reliable transmission. DatalogV1 incorporates self-monitoring for adapting measurement schedules for consumption management and to capture events of interest. Two tests are used to assess the success of the development. The results show an autonomous and robust monitoring system for long-term collection of water level data inmany sparse locations during flood events.
Measurements and Modelling of Base Station Power Consumption under Real Traffic Loads
Authors: Lorincz Josip , Garma Tonko , Petrovic Goran
Published: March 2012

Base stations represent the main contributor to the energy consumption of a mobile cellular network. Since traffic load in mobile networks significantly varies during a working or weekend day, it is important to quantify the influence of these variations on the base station power consumption. Therefore, this paper investigates changes in the instantaneous power consumption of GSM (Global System for Mobile Communications) and UMTS (Universal Mobile Telecommunications System) base stations according to their respective traffic load. The real data in terms of the power consumption and traffic load have been obtained from continuous measurements performed on a fully operated base station site. Measurements show the existence of a direct relationship between base station traffic load and power consumption. According to this relationship, we develop a linear power consumption model for base stations of both technologies. This paper also gives an overview of the most important concepts which are being proposed to make cellular networks more energy-efficient.
Plasticity in the Developing Auditory Cortex: Evidence from Children with Sensorineural Hearing Loss and Auditory Neuropathy Spectrum Disorder
Authors: Cardon Garrett , Campbell Julia , Sharma Anu
Published: March 2012

The developing auditory cortex is highly plastic. As such, the cortex is both primed to mature normally and at risk for reorganizing abnormally, depending upon numerous factors that determine central maturation. From a clinical perspective, at least two major components of development
can be manipulated: (1) input to the cortex and (2) the timing of cortical input. Children with sensorineural hearing loss (SNHL) and auditory neuropathy spectrum disorder (ANSD) have provided a model of early deprivation of sensory input to the cortex and demonstrated the resulting plasticity
and development that can occur upon introduction of stimulation. In this article, we review several fundamental principles of cortical development and plasticity and discuss the clinical applications in children with SNHL and ANSD who receive intervention with hearing aids and/or cochlear
implants.
Current and Planned Cochlear Implant Research at New York University Laboratory for Translational Auditory Research
Authors: Svirsky Mario A. , Fitzgerald Matthew B. , Neuman Arlene , Sagi Elad , Tan Chin-Tuan , Ketten Darlene , Martin Brett
Published: March 2012

The Laboratory of Translational Auditory Research (LTAR/NYUSM) is part of the Department of Otolaryngology at the New York University School of Medicine and has close ties to the New York University Cochlear Implant Center. LTAR investigators have expertise in multiple related disciplines
including speech and hearing science, audiology, engineering, and physiology. The lines of research in the laboratory deal mostly with speech perception by hearing impaired listeners, and particularly those who use cochlear implants (CIs) or hearing aids (HAs). Although the laboratory’s
research interests are diverse, there are common threads that permeate and tie all of its work. In particular, a strong interest in translational research underlies even the most basic studies carried out in the laboratory. Another important element is the development of engineering and computational
tools, which range from mathematical models of speech perception to software and hardware that bypass clinical speech processors and stimulate cochlear implants directly, to novel ways of analyzing clinical outcomes data. If the appropriate tool to conduct an important experiment does not
exist, we may work to develop it, either in house or in collaboration with academic or industrial partners. Another notable characteristic of the laboratory is its interdisciplinary nature where, for example, an audiologist and an engineer might work closely to develop an approach that would
not have been feasible if each had worked singly on the project. Similarly, investigators with expertise in hearing aids and cochlear implants might join forces to study how human listeners integrate information provided by a CI and a HA. The following pages provide a flavor of the diversity
and the commonalities of our research interests.
History, Archives and the Internet
Authors: Robert Jean-Claude
Published: March 2012

The relationship between historians and archives is generally taken for granted. But this impression is misleading. Across the world, the building of archival collections involves a complicated process of selection and destruction. Traditionally, historians do not really know how this process is being conducted and very often a good proportion of them believe that all documents should be kept. The evolution of history and the questioning of the archives by philosophers cannot be ignored and these have changed the relationship between historians and archives. However, the construction of tomorrow’s archives is happening right now, and historians should be prepared to find a way to participate in this operation. The role of archivists is central in the whole process. In the past, archivists generally received a basic training as historians, but since the 1950s, they have been more and more involved with other disciplines like library or information sciences. They became professionals in a new discipline. Historians should take notice of this reality and be prepared to work with archivists on an equal footing. They must learn what archivists are doing and join them to help create archival collections for the future. The last part of the paper takes a quick looks at the evolution of the Internet as an addition, or rather than as an extension, of archival holdings.
Spin Pumping in a Ferromagnetic/Nonmagnetic/Spin-Sink Trilayer Film: Spin Current Termination
Authors: Harii K. , Qiu Z. , Iwashita T. , Kajiwara Y. , Uchida K. , Ando K. , An T. , Fujikawa Y. , Saitoh E.
Published: March 2012

A Spin Current Generated by Spin Pumping in a Ferromagnetic/Nonmagnetic/Spin-Sink Trilayer Film Is Calculated Based on the Spin Pumping Theory and the Standard Spin Diffusion Equation. By Attaching the Spin-Sink Layer, the Injected Spin Current Is Drastically Enhanced when the Interlayer Thickness Is Shorter than the Spin Diffusion Length of the Interlayer. We Also Provided the Formula of the Charge Current which Is Induced from the Pumped Spin Current via the Inverse Spin-Hall Effect.
Investigating the thermal efficiency of commercially available thermo-foils in Sri Lanka
Authors: Maduranga Alawaththage D. , Sumathipala H.H. , Jayatissa N.W.K.
Published: March 2012

The thermo-foil is an insulation material which can be used to insulate roofs of residential buildings which causes less energy to accomplish a comfortable temperature inside the building. It’s becoming popular in Sri Lankan building construction sector. In this research, an investigation of the efficiency of the thermo-foils is done for commonly used brands. The important thermal properties are analyzed for thermo-foils with a thickness of 3mm, 5mm and 8mm and it is tested using a miniature building model for the further evaluation of the efficiency. It was observed that the aluminium layer of the thermo-foil could reflect most of the radiation back and the polyethylene foam layer could keep a temperature gradient of a few degrees. A temperature drop of 1.6 to 2.8 degrees was noted. The results obtained were discussed with an analysis of the thermal insulation properties. A heat transfer model for a residential building was also proposed.Keywords: Thermo – foils; Thermal conductivity; polyethylene foam; roof insulationDOI: http://dx.doi.org/10.4038/josuk.v6i0.4217J Sci.Univ.Kelaniya 6 (2011) : 01-12
Automatic segmentation of separately pronounced Sinhala words into syllables
Authors: Priyadarshani P. G. N. , Dias N. G. J.
Published: March 2012

Aligned corpora are widely used in various speech applications like automatic speech recognition, speech synthesis, as well as prosodic and phonetic research. The segmentation into syllables can be done manually or automatically. But it consumes significantly more time for a fully manual phonetic segmentation and practically it is a complicated task because in many cases it requires a large aligned speech corpus.  If the manual syllabification is done by a group of individuals then the consistency is decreased because the analysis variations of the individuals. Consequently, there is a dire need for automatic syllabification and it is important because Sinhala language is syllable centric in nature. A method for syllabification of acoustic signals of separately pronounced Sinhala words has been given. Detecting the syllable boundaries was achieved by two main phases and those phases have been described with examples.  Keywords: syllabification; oscillograph; vowel; consonant; envelope; thresholdDOI: http://dx.doi.org/10.4038/josuk.v6i0.4219 J Sci.Univ.Kelaniya 6 (2011) : 35-44
An integrated approach to the management of rice root knot nematode, Meloidogyne graminicola in Sri Lanka
Authors: Amarasinghe L. D.
Published: March 2012

This study was carried out to design tools for integrated management of root knot nematode, Meloidogyne graminicola, in rice in Sri Lanka. Rice varieties namely, At5, At353, Bg304, Bg305, Bg359, Bg450, Bg94-1, Bg379-2, Ld355 and Ld356 were tested for their reactions against M. graminicola. Effect of poultry manure, cow-dung and paddy husk with or without cinnamon-leaf oil in reducing M. graminicola was studied.It was revealed that rice varieties At5, At353, Bg304, Bg305, Bg450, Bg379-2, and Ld356 were tolerant to M. graminicola as compared to Bg94-1 which is highly susceptible with high rate of reproduction. Plants treated with poultry manure had significantly low nematode population. Plants grown in poultry manure enriched soil had lower yellow and dead leaves as compared to other plants. Addition of cinnamon-leaf oil improved the nematode control. This study concludes that rice varieties namely At353, Ld356, Bg304, At5, Bg305, Bg450 and Bg379-2 can be used for fields that are prone to M. graminicola infestation while poultry manure can be utilized at least occasionally as a nematicide cum fertilizer to reduce nematode infestation level in rice plants and to improve soil fertility.Keywords: cinnamon-leaf oil; soil amendments; rice variety; root knot nematodeDOI: http://dx.doi.org/10.4038/josuk.v6i0.4221J Sci.Univ.Kelaniya 6 (2011) : 55-63
CD80 Expression on B Cells Regulates Murine T Follicular Helper Development, Germinal Center B Cell Survival, and Plasma Cell Generation
Authors: Good-Jacobson Kim L. , Song Eunice , Anderson Shannon , Sharpe Arlene H. , Shlomchik Mark J.
Published: March 2012

Germinal center (GC) B cells and T follicular helper (TFH) cells interact in the production of high-affinity long-lived plasma cells (PCs) and memory B cells, although the mechanisms regulating the formation of these long-lived populations remain unclear. Because CD80 is one of the few markers shared by human and murine memory B cells, we investigated its role in the development of GCs, memory cells, and PCs. In CD80-deficient mice, fewer long-lived PCs were generated upon immunization compared with that in B6 controls. In concert, the absence of CD80 resulted in an increase in apoptotic GC B cells during the contraction phase of the GC. CD80−/− mice had fewer TFH cells compared with that of B6, and residual TFH cells failed to mature, with decreased ICOS and PD-1 expression and decreased synthesis of IL-21 mRNA. Mixed bone marrow chimeras demonstrated a B cell-intrinsic requirement for CD80 expression for normal TFH cell and PC development. Therefore, B cell expression of CD80 plays a critical role in regulating B–T interactions in both early and late GC responses. This, in turn, results in impaired ability to produce long-lived PCs. These data provide new insights into the development of GCs and Ab-forming cells and the functions of CD80 in humoral immunity.
Vertebral Bone Mineral Measures and Psychological Wellbeing among Individuals with Modic Changes
Authors: Briggs Andrew M. , O'Sullivan Peter B. , Foulner Deryck , Wark John D.
Published: March 2012

Purpose

This case-control pilot study examined whether vertebral bone mineral measures were associated with the presence of chronic low back pain (CLBP) and Modic changes (MCs), and to compare psychological wellbeing and inflammation among individuals with CLBP and MCs, compared to individuals with no history of low back pain and without MCs.

Methods

Eleven individuals with MRI-defined MCs in the lumbar spine and CLBP (cases) and 10 individuals with no history of CLBP or MCs (controls) responded to standard questionnaires regarding pain characteristics and psychological health. Bone mineral density (BMD) was measured with postero-anterior and lateral-projection dual energy X-ray absorptiometry (DXA) to estimate areal BMD (aBMD) and apparent volumetric BMD (ap.vBMD). High sensitivity serum C-reactive protein (hsCRP) was measured as an index of inflammation.

Results

While there was no difference between the groups in measures of depression, anxiety and stress, cases reported significantly greater pain catastrophizing attitudes ( P < 0.01). hsCRP concentrations did not differ between groups ( P = 0.54). Among the 7 cases where MCs were identified between L3–4, significantly higher mean aBMD was observed at the affected vertebral level, compared to the adjacent, unaffected, cephalad level ( P = 0.01–0.04), but not when ap.vBMD was calculated ( P = 0.36).

Conclusions

Vertebral BMD is not reduced among individuals with CLBP and MCs compared to a control group, although pain catastrophizing attitudes are increased among individuals with CLBP and MCs.
Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling
Authors: Han Aiqin , Dai Minhan , Kao Shuh-Ji , Gan Jianping , Li Qing , Wang Lifang , Zhai Weidong , Wang Lei
Published: March 2012

We examined the dynamics of dissolved inorganic nitrogen (DIN, nitrate + nitrite), dissolved inorganic phosphorus (DIP), and silicate (Si(OH)4) in the northern shelf of the South China Sea in summer, which is under a complex hydrodynamic scheme largely shaped by river plume and coastal upwelling, along with the enhanced biological consumption of nutrients therein. The Pearl River plume, with high nutrient concentrations (∼ 0.1–14.2 µmol L−1 for DIN, ∼ 0.02–0.10 µmol L−1 for DIP, and ∼ 0.2–18.9 µmol L−1 for Si(OH)4), occupied a large area of the middle shelf (salinity < 33.5). The nearshore area had high nutrient concentrations apparently sourced from subsurface nutrient‐replete waters through wind‐driven coastal upwelling. These nutrient levels were significantly elevated relative to those on the oligotrophic outer shelf where DIN, DIP, and Si(OH)4 concentrations dropped to < 0.1 µmol L−1, ∼ 0.02–0.03 µmol L−1, and ∼ 2.0 µmol L−1, respectively. A three end‐member mixing model was constructed based on potential temperature and salinity conservation to assess biological consumption of inorganic nutrients, which was denoted by Δ and defined by the deviation from conservative mixing. In the coastal upwelling zone and deep chlorophyll maximum layer, the nutrient uptake ratio ΔDIN : ΔDIP was 16.7, which is the classic Redfield ratio. In contrast, in the river plume the uptake ratio was 61.3 ± 8.7. We believed that an alternative non‐DIP source likely contributed to this higher DIN : DIP consumption ratio in the river plume regime. Meanwhile, Si(OH)4 showed predominant consumption in the river plume and a combination of regeneration and consumption along the path of the coastal upwelling current.
Coastal fronts set recruitment and connectivity patterns across multiple taxa
Authors: Woodson C. B. , McManus M. A. , Tyburczy J. A. , Barth J. A. , Washburn L. , Caselle J. E. , Carr M. H. , Malone D. P. , Raimondi P. T. , Menge B. A. , Palumbi S. R.
Published: March 2012

We show that ocean fronts set recruitment patterns among both community‐building invertebrates and commercially important fishes in nearshore intertidal and rocky reef habitats. Chlorophyll concentration and recruitment of several species of intertidal invertebrates (Balanus spp., Chthamalus spp., Mytilus spp.) and rockfishes (Sebastes spp.) are positively correlated with front probability along the coast of the California Current Large Marine Ecosystem. Abundances of recent settlers and adults for nearshore rockfish species are also positively correlated with front probability. The interaction of coastal topography and bathymetry sets spatial scales of fronts and consequently recruitment at approximately 50 km during active upwelling, compared to 200 km or greater during non‐upwelling periods. Such relationships between fronts and recruitment are likely to be consistent across other marine ecosystems—from coastal waters to the open ocean—and provide a critical link between adults and widely dispersing young. Ocean fronts, already known as features with high biodiversity and resilience in pelagic habitats, also set recruitment and connectivity patterns across multiple taxa for intertidal and rocky reef communities, thus linking biodiversity and resilience in coastal and benthic habitats as well.