bluuebunny/crossref_metadata_2025 huggingface dataset:
Developments in the Magpore Method for Characterising Pore Fabrics and Permeability Anisotropy in Clastic and Fracture Reservoirs
Authors: Hailwood Ernie
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

The magpore method determines the pore fabric of sediment samples by saturating the pore network with a magnetic fluid, then using anisotropy of magnetic susceptibility (AMS) measurements to define the preferred orientations of pore long and short axes. The full 3-D permeability anisotropy of the sample can be predicted from the results, particularly the anisotropy degree and directions of maximum and minimum permeability. The reliability of the method has been confirmed by comparing magpore data with directly-measured 3-D permeability anisotropy on sets of test samples. Examples will be shown that illustrate applications of the method to determining matrix porosity anisotropy in a range of different hydrocarbon reservoir facies. Results demonstrate that, in addition to the well-documented difference between vertical (KV) and horizontal (KH) permeability, many formations also exhibit azimuthal permeability anisotropy (ie variations in KH) of 10 to 20% or more, which is large enough to exert a significant influence on the fluid-flow properties of the reservoir. A particular attribute of the magpore method is that 3-D pore fabric measurements can be made directly on individual samples ranging in size from a few mm to several cm and on groups of samples spanning several metres or more. Thus, the method can provide permeability anisotropy data on spatial scales ranging from individual thin beds to metre-scale sand bodies. Applications of magpore for characterising microfracture fabrics in fracture reservoirs will also be illustrated. Laboratory loading experiments monitored by magpore measurements demonstrate that penetrative microfracture fabrics may develop at applied stresses well below the catastrophic failure stress of the rock (at which visible mesofractures appear). These microfracture networks can be characterised by the magpore method and potentially make a significant contribution to the porosity and permeability properties of these reservoirs.
Numerical Computation of Mitigation and Extinction of Large Scale Fires by Water Mist Systems
Authors: Magnussen Bjorn Fossmo , Evanger Trond , Grimsmo B. , Lilleheie Nils Inge
Published: February 2016

Water is an efficient and environmental friendly means to mitigate and extinguish fires. However, it is not easy to judge the efficiency of water based mitigation and extinction systems due to complexity of the physics and geometry. Therefore advanced computation systems, like Kameleon FireEx KFX®, must be utilized for a prediction of the interaction between the fire, its environments and the water droplets.

Generally water droplets do not extinguish fires in the gas phase. When water droplets hit a fuel-emitting surface like a pool of hydrocarbons, or a burning surface material, then the fire may become extinguished. Water droplets and water vapour do, however, have a mitigating effect on both kinds of fires due to the screening of radiative heat transfer.

Water droplets can also extinguish fires in the gas phase when they become small enough, i.e. in the size range of 100 µm because then they become small enough to interact with the reacting structures in the flame, which are in the same size range. Water mist systems are extinguishing systems of this kind.

The basic physics related to fire evolution and the interaction with water droplets is discussed, including droplet movement, evaporation, radiation screening, spectral effects, extinction, droplets interaction with fire engulfed objects etc.

The paper includes extensive demonstration of computational studies performed for the oil and gas industry. These computations have had major impact on fire strategies and technical solutions on installations worldwide.

Physics of fires

Due to buoyancy forces created by the big temperature differences, the flow pattern in a fire is turbulent. The turbulence is characterized by vortices in a wide spectrum of sizes, ranging from the dimensions of the linear scale of the fire down to, and even smaller than, the so-called Kolmogorov scales. This means from meters down to fractions of a millimeter. The mechanical energy of turbulence, k, is created through the interaction between the mean flow and the turbulence. While the production of k takes place in the larger scales of turbulence its dissipation takes place in the smallest vortices in the fine structures of turbulence, where the molecular mixing takes place. This is consequently the domain for the chemical reactions.

The above is inherent in turbulent combustion in general whether it is in fires, gas turbine combustors or piston engines.

Figure 1 shows a cut through a laminar diffusion flame taken by the Laser Induced Fluorescence technique (LIF) depicting a reacting specie. Figure 2 is a similar cut through a premixed turbulent flame.
Integrated Subsurface Geology and Biosteering: A Case Study From the Sajaa Field, Sharjah, UAE
Authors: Marshall Paul Robert , Burchette Trevor , Ali K.S.
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

A case study is presented to show how close integration of continual subsurface geological insight and wellsite biosteering data generation and interpretation played a key role in ensuring commercial and technical success of the underbalanced, coiled tubing drilling (UBCTD)campaign at the mature Sajaa gas/condensate field. Reservoir pressure depletion had led to UBCTD being required to increase both rates and reserves. Commercial and technical success was known to depend heavily on maximisation of reservoir exposure in the multiple target intervals within Thamama Group limestones. The field presented complex geology: major and minor folding and faulting; lateral facies variations; problems in field boundary delineation. Despite exhaustive efforts, seismic interpretation was unable to provide sufficiently precise resolution for well planning and monitoring if the aim of maximised reservoir penetration was to be achieved. As the campaign progressed, the key role played in achieving the aim by the integration of subsurface geology, realtime GR and wellsite biosteering (analysis of fossils and limestones from extremely small cuttings samples) was increasingly recognised. Continued development of office- and wellsite-based techniques during drilling of 164 laterals in 28 wells led to optimisation of reservoir penetration in ways and to extents considerably beyond those initially anticipated. Optimisation was achieved as: high percentage of borehole length in target; extension of achievable reach (beyond initially believed limits); curtailment of drilling for unachievable targets; realignment of boreholes encountering unpredicted geological complications (including poor target parameters); and by rapid re-planning of later trajectories based on interpretations obtained during drilling. Accumulated information was used during and after the campaign to: modify plans; generate new plans; improve geological understanding; reassess the completeness of the campaign; and form the basis of the proposal for a further campaign. Successful application of this technique with great future potential has continued elsewhere in the region.
Getting the Last Gasp: Deliquification of Challenging Gas Wells
Authors: Bondurant Alison Vergari , Dotson Bryan Dale , Oyewole Peter Olugboyega
Published: February 2016

A common characteristic of "challenging" unconventional gas resources, namely low permeability sands, shale and coal bed methane, is that the ultimate recovery is dependent on economic removal of liquids accumulation, generally termed "deliquification". This resource is making up an ever-increasing part of the North American gas supply. Since there is no one "perfect solution", and the problem affects thousands of wells, the opportunity involves not only technology development but also knowledge management and building resource capability.

This paper outlines the scope of impact and opportunity in North America, followed by the industry's approach and progress in the arena. The North American industry is working a variety of deliquification technologies for "challenging" gas, with developments ranging from adapting existing oil-field technologies, to developing gas-specific technologies, to "on the horizon" technologies. Examples in each stage of the development process will be shown.

The effective communication of these developments to operators and suppliers is also a necessary component. The industry-wide annual conferences that have emerged in the last seven years are the primary avenue for this communication, and are supplemented in some cases by operator internal networks.

This combination of technology development and effective communication is increasingly allowing North American operators to maximize the recovery of challenging gas resources.

Context

Economic Context.

North America is one of the largest natural gas markets in the world, and is supplied primarily from domestic production. In 2006, North America (Canada, Mexico and the United States) produced 73 BCF/d and consumed 74.5 BCF/d (1); this represents about one quarter of the world gas supply and demand.

A distinguishing characteristic of North American land-based gas production is the large number of low rate wells. For example, in the continental United States, the majority of gas wells produce less than 100 Mscfd. Figure 1 shows the well count distribution for a significant portion of United States gas production. The low rates reflect the maturity of North American gas production and the predominance of "challenging" production from low permeability sands (less than 0.1 mD), shale and coal bed methane.

Figure 1: Gas rate distribution for North American gas wells.

Low rate gas wells almost always cease production due to liquids accumulation in the wellbore. Consequently, deliquification of low rate gas wells is of great importance to North American gas producers.

Coupled with this technical challenge is that the scarcity of gas in the market has increased gas prices substantially in the last 10 years. As shown on Figure 2, wellhead gas prices have roughly tripled in the past 10 years (2). Consumers are providing the economic incentive to produce low rate gas wells beyond the natural flow of the well.
Improving Oil Recovery through Integrated Reservoir Management In A Mature Oil Field In The Middle East
Authors: Chouhdary Muhammed Akram , Al-Rasheedi Hussain Rakeb , Wani Mohamad Rafiq
Published: February 2016

Extended Abstract

Paper illustrates that how the application of innovative technology and principles of integrated reservoir management can improve recovery efficiency in a mature oil field. The paper discusses key principle of effective reservoir management. Effective reservoir management is a combination of capability, viability and processes. The application of the principle is illustrated with an example of a case study of Wafra Ratawi reservoir, a lower craterous Oolite reservoir is in a giant mature oil field Wafra.

The field was discovered in 1954 and is located in the Neutral Zone between Kuwait and Saudi Arabia. The mineral rights in this region are shared equally by both countries. The field is now operated jointly by Saudi Arabian Chevron (100 % owned subsidiary of Chevron) and Kuwait Gulf Oil Co. The reservoir is an anticline with 2 lobes East Wafra and Main Area. The reservoir has varying oil gravity with low bubble point pressure. The Production from this reservoir started in 1957. The field was shut in during the first Gulf war, and the increase in average reservoir pressure was observed, signaling for existence of partial aquifer support.

After an extensive geologic and engineering study, the production strategy to produce above the bubble point pressure was adopted. However, because of the weak aquifer support, the reservoir pressure started to decline rapidly. The simulation model in 1995 indicated a significant opportunity to enhance the asset value through recovery improvement (IOR) techniques.

Based on the sound reservoir engineering practices, detailed reservoir studies, low cost and higher economic benefits the peripheral water injection was selected as preferred method for initiating reservoir pressure maintenance. The pressure maintenance project (PMP) was implemented in 1998. The Pressure Maintenance Plant was designed to handle all produced waters in the Wafra field with varying salinity and H2S contents.

A depletion strategy objected at optimum reservoir management and maximum oil recovery was adopted. Following are the key features of depletion strategy.Target Injection ratea) Phase -1 Injection/Production rate > 1b) Phase-2 Injection/ Production rate ~ 1Maintain Optimum Draw Down in producing wells.Take maximum benefit of water front movement.Manage problems related to vertical permeability distribution.
Investigation of Miscible Gas Flooding in North Kuwait Reservoirs by Experimental and Modeling Approaches
Authors: Al-Mayyan Haya Ebrahim , Al-Anzi Ealian H.D. , Al-Ajmi Moudi Fahad
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

The North Kuwait (NK) long term strategy is designed to increase its oil production as per Kuwait Oil Company (KOC) development plans. North Kuwait's production to date is characterized by large, massive reservoirs undergoing natural depletion supported by strong natural aquifer drives and, in some reservoirs, natural aquifer support is supplemented by waterflooding. In order to maintain production, the current primary and secondary (waterflood) recovery mechanisms must be advanced into secondary and tertiary (EOR) in the main NK reservoirs. To date, there is zero EOR production from KOC reservoirs. Very limited lab work has been conducted with majority of it on NK reservoirs. These experiments include (1) Swelling tests, (2) Slim-tube tests, (3) Composite core immiscible tertiary Gasflood. This study is the first to define a comprehensive EOR lab studies in a systematic manner to assess the EOR potential in NK. The study focuses on gas injection EOR option, as more than 90% of NK reservoirs are suitable candidates for this method. The injectant gases considered are pure and impure CO2, N2, and hydrocarbon gases. This paper presents a review of the previous lab work, and recommend to perform additional laboratory tests for each major reservoir in NK. Specific attention is focused on KOC limited gas injection experiments. These tests have been a useful tool for EOR screening of NK reservoirs, as: Equation of State (EOS) has been developed and used for simulation these injection studies,One-Dimensional (1D) slim-tube compositional simulation models were built using the matched EOS to validate slim-tube test data,Additionally, the available Minimum Miscibility Pressure (MMP) correlations were used for comparison.

The paper also presents the approach to predict the MMP of NK reservoir fluids with various injection gases other than the gases used in the actual experiments.
Angudan Revisited: - Using Old Data To Explore for New Targets in a Frontier Area
Authors: McIlroy James Graham
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

Newly acquired modern long-offset 2D seismic data in conjunction with gravity and magnetic data has provided a more complete picture of the deep prospectivity of the South Oman Salt Basin. Deeper potential that was poorly imaged previously is now targeted to unlock future potential for the Block. The Angudan area of the South Oman Salt Basin was first explored in the 1960's using surface geology and low-fold seismic data. This resulted in several shallow wells that tested seismic-delineated structural closures. The failure of these wells lead to a shift of exploration to the more prospective and more successful areas in Northern and Central Oman during the following years. The discoveries in the 1980's refocused exploration to the South where the Ara carbonate stringers proved to be a valid and prolific reservoir. Although the Angudan area was revisited with improved seismic coverage, the data was not of sufficient quality to resolve the deeper horizons. The Angudan-1 well drilled in 1990 penetrated the deepest mappable marker but failed to find any reservoirs. It stopped short of the Ara carbonates. As focus has shifted again to the South in the last few years, the deeper South Oman Salt Basin reservoirs were targeted using long offset seismic data and a 2D grid down to 1 km spacing. Although the rugged terrain and various access issues in the area caused access restrictions, an improved image of the Ara carbonates has been obtained. A combination of geophysical techniques has reduced the exploration uncertainties in this frontier area and improved our prospect risk assessment.
New Exploration Play in Basal Burgan Unnamed Clastics, Kuwait
Authors: Thakur Sanjeev S. , Kumpas Michael George , Al-Darmi Areej
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

Unnamed clastics at the base of Burgan offer a hitherto un-explored hydrocarbon play in onshore Kuwait. It is a sub-unconformity play and comprise a composite sequence with three systems tracts upwards, namely; transgressive, highstand and followed by another transgressive package. Thickness of whole package varies between 10 and 145' (generally between 37'to 60', net pay 40'). Sand bodies in the transgressive system tracts are discontinuous laterally and vertically and that of the highstand system tracts are fairly continuous sheets and shale-out in the distal settings. Thin channel sand bodies of lower transgressive and highstand units entrap oil whenever upper transgressive unit provides effective top seal. The effectiveness of the top seal depends on the vertical limits of incision by overlying lowstand Burgan clastics. The trapping is controlled by both stratigraphic and structural components. In most of the wells targeting Lower Cretaceous or deeper, casings are generally set within this unit, often proper logs are not run across the section. However, some of the wells have partial suit of logs and well cutting. The resource remained largely unaccounted and unexplored. The play has been identified in Ratqa, Mutriba, Medina and Raudhatain areas. A case study is presented from the Raudhatain Area.
Exploring for Subtle Stratigraphic Carbonate Traps Within the Upper Shuaiba of Oman
Authors: De Leeuw Kees , Gonguet Christophe
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

Since mid-2003, Petroleum Development Oman has been successfully exploring the stratigraphic Upper Shuaiba play in North Oman. Play understanding has significantly evolved and to date three discoveries have been made. Prograding Aptian shoals and mounds into the Bab Basin interfinger with argillaceous limestones and are truncated by Nahr-Umr shales. Individual reservoirs, in the clinoform apex, are too thin to be resolved on seismic. Stacked clinoform geometries can be observed directly in seismic sections. Delineating these geometries, attribute maps and particularly spectral decomposition maps are used enabling visualisation of tuning bands of the inclined sequences terminating against Nahr-Umr. Frequency slice analyses determine the potential location of reservoir belts or prospects. Spectral decomposition is used to predict reservoir thickness using calibrated analogues. Sequence based geological modelling has resulted in facies distributions over the Bab Basin and the carbonate platforms beyond. The detailed 3D model enables to constrain general trends of the tuning belts observed in seismic. As seismic artefacts are interfering with the actual primary reflections, false trends not aligning with the geological model may be discarded. Seismic modelling shows that porous reservoirs have similar impedance as the Nahr-Umr. The clinoforms present imply that Top Shuaiba is not a uniform hard-kick pick; phase is depending on reservoir thickness and manual picking is necessary. Well placement and geosteering are key factors in increasing success and maximising the value of discoveries. Facies demands a vertical pilot hole placed downdip of an expected sequence and a horizontal sidetrack is designed to follow an individual clinoform stratigraphically updip where reservoir is only a few metres thick. PeriScope (Schlumberger) has added value, enabling to maximise the extent of producible reservoir without unwanted exits and converting a discovery into a producer within a period of one month.
The Late Permian-Early Triassic Khuff Formation in the Middle-East: Sequence Biostratigraphy and Palaeoenvironments by Means of Calcareous Algae and Foraminifers
Authors: Gaillot Jeremie
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

The carbonates and evaporites of the Late Permian Khuff Formation form widespread reservoirs across the Arabian plate and concentrate the biggest gas resources in the world. The material studied includes 1500 samples from outcrops in Iran (Zagros), Turkey, Saudi Arabia and South China. The objectives of the study were (1) to build a robust biotratigraphic framework based on a detailed description of algal-foraminiferal biotic content, (2) to characterize the depositional environments and their temporal successions during the Late Permian and Early Triassic. By comparison of fossils distribution, the Middle/Late Permian Khuff deposits are divided into 8 units limited at their tops by turnovers levels, corresponding to significant reshapings of biotic assemblages. During the Late Permian, the Zagros (Iran), Taurus (Turkey), South China and even Japan share similar foraminiferal assemblages and represent intermittently connected palaeobiogeographic provinces. Palaeoecological results show that the structurally controlled palaeohighs are successively drowned and that the system evolves progressively from a rimmed platform towards an almost uniformly fl at ramp. The major oolitic units (reservoirs) developed within high-subsiding areas by sediment volume funneling, mainly during the late Wuchiapingian (upper K4 reservoir equivalent) and early triassic (K2 reservoir equivalent). The thermal subsidence during the Neotethyan spreading is likely the main factor that drove the Khuff deposition on the Arabian platform and can be related to the demise of the regional permian fauna. The new framework is expected to provide an important tool for further subsurface studies and correlations.
Chronostratigraphy and Source Rock Presence within the Silurian Qusaiba of Qatar
Authors: Reaves Chris , Abdulla Ismail A. , Alway Robert H.S. , Zahran Mamdouh , Moore Leonard , Molyneux Stewart
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

The Qusaiba Formation is the primary source rock for the prolific Paleozoic plays being explored and developed in the Middle East. The super giant Qatar North Field accumulation alone is estimated to contain 900 TCF of recoverable reserves. We have evaluated stratigraphic and facies relationships within the Silurian, including the Qusaiba Formation, as part a systematic evaluation of hydrocarbon prospectivity commissioned by Qatar Petroleum. Well penetrations of the Silurian section in Qatar were integrated with the established regional distribution of the Silurian across the Arabian Platform. Biostratigraphic dating yielded a chronostratigraphic range of Early Silurian (Rhuddanian) to Late Silurian (Wenlockian), with an overall age range of 443Ma to 425Ma. These age dates improved the lateral correlation of second-order maximum flooding surfaces and led to revisions of the standard Silurian lithostratigraphic correlation. The Qusaiba in Qatar was determined to contain three separate source horizons. 1. A Rhuddanian 'hot' shale restricted to paleo-topographic lows established on the underlying Ordovician, 2. A Mid-Aeronian 'hot' shale associated with the early Silurian maximum flood. This horizon is laterally extensive, but the thickest along the western margin of the Qatar Arch, and 3. A Wenlockian lean, 'cool' shale extending over the whole of Qatar. Organic geochemical and petrographic analyses were used to determine source type and richness. Samples were 'back-tracked' to determine original (thermally immature) organic carbon (TOC) and hydrocarbon potential (HI) values. 'Paleo-thermometry' data from palynomorphs (TAI), conodonts (CCI) and acritarchs (AAI) provided additional control on organic maturity.
Vertical Seismic Profile (VSP): Beyond Time-to-Depth
Authors: Hornby Brian , Yu Jianhua
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

VSP or Vertical Seismic Profile was originally designed and is currently primarily used, to give us time-to-depth for seismic-well tie. Beyond time-to-depth a number of possibilities exist. Recently, there has been considerable interest in VSP imaging with extensive surveys being acquired both on land and offshore. Modeling studies using full-waveform finite-difference method (FDM) show us what we can image for a particular acquisition geometry and geology, with best image results seen with 3D VSP surveys incorporating a large VSP array in the well and an areal grid of surface sources obtained using a seismic shooting vessel. Traditionally, VSP imaging has been implemented using surface seismic processing algorithms. However, the VSP geometry poses its own challenges and unique opportunities. In this talk we will discuss the state of the art of the technology, what technologies are appropriate for different settings, and what the future may bring. Results will be shown from deepwater Gulf of Mexico prospects and we will discuss how these results have impacted our understanding of the reservoir and reduced risk on development well placement. On imaging algorithms we will examine some exciting new developments to develop specialized algorithms to take advantage of the opportunities posed by the VSP geometry. These developments include controlled local beam methods to improve image quality, imaging using multiples and interferometric imaging of salt flanks and structure below complicated overburden.
Reservoir Monitoring Using Permanent In-Well Seismic
Authors: Hornby Brian , Barkved Olav Inge , Williams Brock , Bostick Tad
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

The world's first successful installation of a permanent borehole seismic system in an offshore production well was executed at Valhall. The system is fibre-optic based and consists of 5 levels of 3C seismic sensors spaced 13.5 m apart. Permanent borehole seismic is seen as complementary to the permanent seabed seismic array with the following goals:4D seismic calibration. Use the directly recorded downhole signal to calibrate the surface seismic signal. This might best be done in conjunction with instrumented seabed seismic receivers for full-field monitoring.4D VSP. With several wells instrumented, use surface sources and downhole sensors for reservoir monitoring. Micro-seismic monitoring.

Passive monitoring of faulting caused by reservoir compaction and fluid fronts and active monitoring of cuttings injection and well stimulation. Surveys have been conducted with simultaneous acquisition of permanent seabed and borehole arrays using both active surface sources and passive noise. The active seismic data are of good quality and processing yields high-resolution images to a distance of 400m from the borehole, complementing the lower-resolution surface seismic data. Time-lapse measurements are planned in 2007, with the main objective being to measure pressure changes in the reservoir due to injection from a nearby well. In parallel passive data are analyzed for potential for reservoir monitoring of fluid fronts using micro-seismic data. Additional work relates to calibration of the 4D seismic response for changes in the overburden.
3D FEM modelling for stress simulation and experimental investigation of dual-gradient coating using PVD
Authors: Li Bin
Published: February 2016

In this work, AlZrCrN composite dual-gradient coating was deposited on cemented carbide substrate using physical vapor deposition. Using the composite dual-gradient structure design, the thermal residual stress between layers was decreased and the bonding strength between coating and substrate was increased. Finite element simulation indicates that thermal residual stress in composite dual-gradient coatings is significantly smaller than that in CrN and ZrN single coatings. The bonding strength between composite double-gradient coating and substrate is found to be greater than that of the single-layer coating. The factors and conditions influencing the performance of composite dual-gradient coating can be obtained through numerical calculation. Based on the simulation, coating structure that has a gradual transition from the internal high-plastic long-comb Cr/CrN layer to the outer AlZrCrN wear-resistant layer with stubby morphology was prepared.
A combination of high electrical conductivity and mechanical strength in AA1070 commercially pure aluminum wires fabricated by KoBo extrusion
Authors: Polkowska Adelajda
Published: February 2016

In this work, the effect of KoBo extrusion process parameters on the extrusion force, microstructure, mechanical properties and electrical resistivity of wires fabricated from AA1070 commercially pure aluminum, is analyzed. It is found that applied parameters of the KoBo extrusion process have a strong impact on changes in the extrusion force. The smallest variation of the extrusion force was recorded for the KoBo extrusion conducted with a small oscillation angle and a high extrusion rate. The relatively small alteration of the extrusion force results in a more homogeneous microstructure and mechanical properties of the wires. As compared to the material in the annealed state, the KoBo extruded wires exhibit almost two-fold higher ultimate tensile strength and only a slightly lowered electrical conductivity. The best combination of electrical conductivity and mechanical strength was 60.3 % International Annealed Copper Standard and ultimate tensile strength of 152 MPa, respectively. These results are highly competitive to those reported for AA1070 aluminum subjected to other continuous plastic deformation methods (e. g. the cryorolling combined with a heat treatment). A high electrical conductivity and enhanced mechanical properties (in respect to the as annealed material), clearly indicate that the KoBo extruded AA1070 wires are potentially useful for moderately loaded electrical engineering applications.
Highly Efficient Preparation of Amides from Aminium Carboxylates Using N-(p-toluenesulfonyl) Imidazole
Authors: Behrouz Somayeh , Rad Mohammad Navid Soltani , Forouhari Elham
Published: February 2016

Treatment of aminium carboxylates with N-(p-toluenesulfonyl)imidazole in the presence of triethylamine in DMF at 100 °C afforded the corresponding amides in good to excellent yields. N-(p-Toluenesulfonyl)imidazole proved to be a highly efficient coupling reagent for the preparation of numerous structurally diverse primary, secondary and tertiary amides.
A Microfluidic Device for Hydrodynamic Trapping and Manipulation Platform of a Single Biological Cell
Authors: Ahmad Khalili Amelia , Ahmad Mohd , Takeuchi Masaru , Nakajima Masahiro , Hasegawa Yasuhisa , Mohamed Zulkifli Razauden
Published: February 2016

To perform specific analysis for the single cell, individual cells have to be captured and separated from each other before further treatments and analysis can be carried out. This paper presents the design, simulation, fabrication, and testing of a microfluidic device for trapping a single cell/particle based on a hydrodynamic technique. A T-channel trapping chip has been proposed to provide single-cell trapping and consequently could be a platform for cell treatments and manipulations. A finite element T-channel trapping model was developed using Abaqus FEA™ software to observe it’s trapping ability by optimizing the channel’s geometry and RhMain/RhTrap ratio. A proof of concept demonstration for cell trapping in the T-channel model was presented in the simulation analysis and experimental work using HUVEC cell aggregate. The T-channel was found to be able to trap a single cell via the hydrodynamic trapping concept using an appropriate channel geometry and RhMain/RhTrap ratio. The proposed T-channel single-cell trapping has potential application for single cell characterization and single 3D cell aggregates treatments and analysis.
The Deep Physics Hidden within the Field Expressions of the Radiation Fields of Lightning Return Strokes
Authors: Cooray Vernon , Cooray Gerald
Published: February 2016

Based on the electromagnetic fields generated by a current pulse propagating from one point in space to another, a scenario that is frequently used to simulate return strokes in lightning flashes, it is shown that there is a deep physical connection between the electromagnetic energy dissipated by the system, the time over which this energy is dissipated and the charge associated with the current. For a given current pulse, the product of the energy dissipated and the time over which this energy is dissipated, defined as action in this paper, depends on the length of the channel, or the path, through which the current pulse is propagating. As the length of the channel varies, the action plotted against the length of the channel exhibits a maximum value. The location of the maximum value depends on the ratio of the length of the channel to the characteristic length of the current pulse. The latter is defined as the product of the duration of the current pulse and the speed of propagation of the current pulse. The magnitude of this maximum depends on the charge associated with the current pulse. The results show that when the charge associated with the current pulse approaches the electronic charge, the value of this maximum reaches a value close to h/8π where h is the Plank constant. From this result, one can deduce that the time-energy uncertainty principle is the reason for the fact that the smallest charge that can be detected from the electromagnetic radiation is equal to the electronic charge. Since any system that generates electromagnetic radiation can be represented by a current pulse propagating from one point in space to another, the result is deemed valid for electromagnetic radiation fields in general.
Challenges in Creating Evidence in Environmental Health Risk Assessments: The Example of Second-Hand Smoke
Authors: Fischer Florian
Published: February 2016

Public health interventions are directed to influence the (state of a) risk factor, either by behavioral or environmental changes. Therefore, environmental health risk assessments are highly relevant for public health decision making and policy development. The credibility of an environmental health risk assessment depends, to a large extent, on the strength of the scientific evidence on which it is based. In this article, the main challenges for assessing the impact of a potential adverse health effect from an environmental pollutant are described. Second-hand smoke (SHS) was chosen to illustrate the current state of evidence. The assessment of the impact of potential adverse health effects from environmental risk factors is dependent on several issues, such as the hypothesized health outcome, the nature of the exposure, the dose-response-relationship and the variability and susceptibility of the exposed population. The example of SHS exposure highlights the need for evidence-based public health. Several challenges in terms of study design, assessment methods, as well as data analysis and synthesis with respect to the stratification of results, and consideration of bias and confounding exist. Future research needs to take into account which methods and techniques will be used to generate evidence for population-level decisions.
Medical Geology: Impacts of the Natural Environment on Public Health
Authors: Centeno Jose , Finkelman Robert , Selinus Olle
Published: February 2016

All living organisms are composed of major, minor, and trace elements, given by nature and supplied by geology.
Comparison of Four Ground-Level PM2.5 Estimation Models Using PARASOL Aerosol Optical Depth Data from China
Authors: Guo Hong , Cheng Tianhai , Gu Xingfa , Chen Hao , Wang Ying , Zheng Fengjie , Xiang Kunshen
Published: February 2016

Satellite remote sensing is of considerable importance for estimating ground-level PM2.5 concentrations to support environmental agencies monitoring air quality. However, most current studies have focused mainly on the application of MODIS aerosol optical depth (AOD) to predict PM2.5 concentrations, while PARASOL AOD, which is sensitive to fine-mode aerosols over land surfaces, has received little attention. In this study, we compared a linear regression model, a quadratic regression model, a power regression model and a logarithmic regression model, which were developed using PARASOL level 2 AOD collected in China from 18 January 2013 to 10 October 2013. We obtained R (correlation coefficient) values of 0.64, 0.63, 0.62, and 0.57 for the four models when they were cross validated with the observed values. Furthermore, after all the data were classified into six levels according to the Air Quality Index (AQI), a low level of statistical significance between the four empirical models was found when the ground-level PM2.5 concentrations were greater than 75 μg/m3. The maximum R value was 0.44 (for the logarithmic regression model and the power model), and the minimum R value was 0.28 (for the logarithmic regression model and the power model) when the PM2.5 concentrations were less than 75 μg/m3. We also discussed uncertainty sources and possible improvements.
Integrated WiFi/PDR/Smartphone Using an Adaptive System Noise Extended Kalman Filter Algorithm for Indoor Localization
Authors: Li Xin , Wang Jian , Liu Chunyan , Zhang Liwen , Li Zhengkui
Published: February 2016

Wireless signal strength is susceptible to the phenomena of interference, jumping, and instability, which often appear in the positioning results based on Wi-Fi field strength fingerprint database technology for indoor positioning. Therefore, a Wi-Fi and PDR (pedestrian dead reckoning) real-time fusion scheme is proposed in this paper to perform fusing calculation by adaptively determining the dynamic noise of a filtering system according to pedestrian movement (straight or turning), which can effectively restrain the jumping or accumulation phenomena of wireless positioning and the PDR error accumulation problem. Wi-Fi fingerprint matching typically requires a quite high computational burden: To reduce the computational complexity of this step, the affinity propagation clustering algorithm is adopted to cluster the fingerprint database and integrate the information of the position domain and signal domain of respective points. An experiment performed in a fourth-floor corridor at the School of Environment and Spatial Informatics, China University of Mining and Technology, shows that the traverse points of the clustered positioning system decrease by 65%–80%, which greatly improves the time efficiency. In terms of positioning accuracy, the average error is 4.09 m through the Wi-Fi positioning method. However, the positioning error can be reduced to 2.32 m after integration of the PDR algorithm with the adaptive noise extended Kalman filter (EKF).
Biological Evaluation of Double Point Modified Analogues of 1,25-Dihydroxyvitamin D2 as Potential Anti-Leukemic Agents
Authors: Corcoran Aoife , Nadkarni Sharmin , Yasuda Kaori , Sakaki Toshiyuki , Brown Geoffrey , Kutner Andrzej , Marcinkowska Ewa
Published: February 2016

Structurally similar double-point modified analogues of 1,25-dihydroxyvitamin D2 (1,25D2) were screened in vitro for their pro-differentiating activity against the promyeloid cell line HL60. Their affinities towards human full length vitamin D receptor (VDR) and metabolic stability against human vitamin D 24-hydroxylase (CYP24A1) were also tested. The analogues (PRI-1730, PRI-1731, PRI-1732, PRI-1733 and PRI-1734) contained 5,6-trans modification of the A-ring and of the triene system, additional hydroxyl or unsaturation at C-22 in the side chain and reversed absolute configuration (24-epi) at C-24 of 1,25D2. As presented in this paper, introduction of selected structural modifications simultaneously in two distinct parts of the vitamin D molecule resulted in a divergent group of analogues. Analogues showed lower VDR affinity in comparison to that of the parent hormones, 1,25D2 and 1,25D3, and they caused effective HL60 cell differentiation only at high concentrations of 100 nM and above. Unexpectedly, introducing of a 5,6-trans modification combined with C-22 hydroxyl and 24-epi configuration switched off entirely the cell differentiation activity of the analogue (PRI-1734). However, this analogue remained a moderate substrate for CYP24A1, as it was metabolized at 22%, compared to 35% for 1,25D2. Other analogues from this series were either less (12% for PRI-1731 and PRI-1733) or more (52% for PRI-1732) resistant to the enzymatic deactivation. Although the inactive analogue PRI-1734 failed to show VDR antagonism, when tested in HL60 cells, its structure might be a good starting point for our design of a vitamin D antagonist.
Pharmacological Modulators of Endoplasmic Reticulum Stress in Metabolic Diseases
Authors: Jung Tae , Choi Kyung
Published: February 2016

The endoplasmic reticulum (ER) is the principal organelle responsible for correct protein folding, a step in protein synthesis that is critical for the functional conformation of proteins. ER stress is a primary feature of secretory cells and is involved in the pathogenesis of numerous human diseases, such as certain neurodegenerative and cardiometabolic disorders. The unfolded protein response (UPR) is a defense mechanism to attenuate ER stress and maintain the homeostasis of the organism. Two major degradation systems, including the proteasome and autophagy, are involved in this defense system. If ER stress overwhelms the capacity of the cell’s defense mechanisms, apoptotic death may result. This review is focused on the various pharmacological modulators that can protect cells from damage induced by ER stress. The possible mechanisms for cytoprotection are also discussed.
Ciriottiite, Cu(Cu,Ag)3Pb19(Sb,As)22(As2)S56, the Cu-Analogue of Sterryite from the Tavagnasco Mining District, Piedmont, Italy
Authors: Bindi Luca , Biagioni Cristian , Martini Bruno , Salvetti Adrio
Published: February 2016

The new mineral species ciriottiite, ideally Cu(Cu,Ag)3Pb19(Sb,As)22(As2)S56 has been discovered in the Tavagnasco mining district, Piedmont, Italy, as very rare black metallic tubular crystals, up to 150 μm in length, associated with Bi sulfosalts and arsenopyrite. Its Vickers hardness (VHN10) is 203 kg/mm2 (range 190–219). In reflected light, ciriottiite is light grey in color, distinctly anisotropic with brownish to greenish rotation tints. Internal reflections are absent. Reflectance values for the four COM wavelengths (Rmin, Rmax (%) (λ in nm)) are: 33.2, 37.8 (471.1); 31.8, 35.3 (548.3), 31.0, 34.7 (586.6); and 27.9, 32.5 (652.3). Electron microprobe analysis gave (in wt %, average of 5 spot analyses): Cu 2.33 (8), Ag 0.53 (5), Hg 0.98 (6), Tl 0.78 (3), Pb 44.06 (14), As 4.66 (7), Sb 23.90 (10), Bi 1.75 (7), total 99.38 (26). On the basis of 56 S atoms per formula unit, the chemical formula of ciriottiite is Cu3.23(11)Ag0.43(4)Hg0.43(2)Pb18.74(9)Tl0.34(1)Sb17.30(5)As5.48(10)Bi0.74(3)S56. The main diffraction lines, corresponding to multiple hkl indices, are (d in Å (relative visual intensity)): 4.09 (m), 3.91 (m), 3.63 (vs), 3.57 (m), 3.22 (m), 2.80 (mw), 2.07 (s). The crystal structure study revealed ciriottiite to be monoclinic, space group P21/n, with unit-cell parameters a = 8.178 (2), b = 28.223 (6), c = 42.452 (5) Å, β = 93.55 (2)°, V = 9779.5 (5) Å3, Z = 4. The crystal structure was refined to a final R1 = 0.118 for 21304 observed reflections. Ciriottiite is the Cu analogue of sterryite and can be described as an expanded derivative of owyheeite. The name ciriottiite honors Marco Ernesto Ciriotti (b. 1945) for his longstanding contribution to mineral systematics.
Rank-Based Methods for Selection of Landscape Metrics for Land Cover Pattern Change Detection
Authors: Sinha Priyakant , Kumar Lalit , Reid Nick
Published: February 2016

Often landscape metrics are not thoroughly evaluated with respect to remote sensing data characteristics, such as their behavior in relation to variation in spatial and temporal resolution, number of land cover classes or dominant land cover categories. In such circumstances, it may be difficult to ascertain whether a change in a metric is due to landscape pattern change or due to the inherent variability in multi-temporal data. This study builds on this important consideration and proposes a rank-based metric selection process through computation of four difference-based indices (β, γ, ξ and θ) using a Max–Min/Max normalization approach. Land cover classification was carried out for two contrasting provinces, the Liverpool Range (LR) and Liverpool Plains (LP), of the Brigalow Belt South Bioregion (BBSB) of NSW, Australia. Landsat images, Multi Spectral Scanner (MSS) of 1972–1973 and TM of 1987–1988, 1993–1994, 1999–2000 and 2009–2010 were classified using object-based image analysis methods. A total of 30 landscape metrics were computed and their sensitivities towards variation in spatial and temporal resolutions, number of land cover classes and dominant land cover categories were evaluated by computing a score based on Max–Min/Max normalization. The landscape metrics selected on the basis of the proposed methods (Diversity index (MSIDI), Area weighted mean patch fractal dimension (SHAPE_AM), Mean core area (CORE_MN), Total edge (TE), No. of patches (NP), Contagion index (CONTAG), Mean nearest neighbor index (ENN_MN) and Mean patch fractal dimension (FRAC_MN)) were successful and effective in identifying changes over five different change periods. Major changes in land cover pattern after 1993 were observed, and though the trends were similar in both cases, the LP region became more fragmented than the LR. The proposed method was straightforward to apply, and can deal with multiple metrics when selection of an appropriate set can become difficult.
A Combination of Plant NDVI and LiDAR Measurements Improve the Estimation of Pasture Biomass in Tall Fescue (Festuca arundinacea var. Fletcher)
Authors: Schaefer Michael , Lamb David
Published: February 2016

The total biomass of a tall fescue (Festuca arundinacea var. Fletcher) pasture was assessed by using a vehicle mounted light detection and ranging (LiDAR) unit to derive canopy height and an active optical reflectance sensor to determine the spectro-optical reflectance index, normalized difference vegetation index (NDVI). In a random plot design, measurements of NDVI and pasture height were combined to estimate biomass with a root mean square error of prediction (RMSEP) equal to ±455.28 kg green dry matter (GDM)/ha, over a range of 286 kg to 3933 kg GDM/ha. The combination of NDVI and height measurements were observed to be more accurate in assessing total biomass than just the NDVI (RMSEP ± 846.51 kg/ha) and height (RMSEP ± 708.13 kg/ha). Based on the results of the study it was concluded the use of combined LiDAR and active optical reflectance sensors can help unlock the complex interrelationship between green fraction and biomass in swards containing both green and senescent material.