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The electronic, spectral and structural properties of a molecular machine composed of a phenylene rotator encased by two trityl stators and two acetylides as axis are investigated theoretically to evaluate the rotational dynamics by DFT method. The changes in these properties and intramolecular rotation barriers caused by substituting F, CN, NO2, and NH2 on the central phenylene were also investigated. The potential energy surface calculations showed that the activation barrier of phenylene rotation is lower than 1 kcal/mol, for all considered systems. The results of the computational method were in good agreement with previously reported experimental results. The dynamical features of the studied molecules suggest that this kind of structure can act as a molecular machine at room temperature in the living organisms. The displacement of phenylene hydrogen atoms with polar groups improves this property and it is expected that these compounds may be helpful in drug delivery.

A method was developed for classifying petroleum into four types according to their origin and integrity: marine, non-marine, degraded and thermally transformed. The method was based on the relative proportions of functional groups measured by FTIR spectroscopy. Twenty-one petroleum samples were used for model calibration and six for validation, which were pre-classified. Aliphatic functional group absorption maxima were used at 2919, 2856, 1457 and 1376 cm−1, as well as at 1700 and 811 cm−1 for aromatic groups, and at 1152 and 1030 cm−1 for polar groups (sulphonyl and ether, respectively). Using hierarchical cluster and discriminate analyses, three canonic functions were obtained that classified the samples according to their origin and integrity, with a prediction efficiency of 100%, for both calibration and validation. The canonic functions derived from the discriminate analysis had correlation coefficients of 0.994, 0.900, and 0.867, among the variables studied and the classification factor. The method is efficient for the proposed classifications and can be useful for a range of applications.

Sr0.7Bi0.2TiO3 (SBT) by increasing the proportion and size of polar nano-region. Meanwhile, the BDS remains a high level with x ≤ 0.38 attributed to the addition of KBT with a large band gap. As a result, the 0.62SBT-0.38KBT exhibits a high energy storage density of 2.21 J/cm3 with high η of 91.4% at 220 kV/cm and superior temperature stability (−55 ∼ 150 °C), frequency stability (10 ∼ 500 Hz) and fatigue resistance (105 cycles). Moreover, high pulsed discharge energy density (1.81 J/cm3), high power density (49.5 MW/cm3) and great thermal stability (20 ∼ 160 °C) are achieved in 0.62SBT-0.38KBT. Based on these excellent properties, the 0.62SBT-0.38KBT are suitable for pulsed power systems. This work provides a novel strategy and systematic study for improving energy storage properties of SBT.

International audience; Mass-movements in cold and Polar climates often involve permafrost and ice and hence these two phenomena are recurring themes throughout this chapter. We consider specifically mass movements in glacial, periglacial and paraglacial settings. For each environmental setting we describe the types of mass movement that have been documented in the literature, describing the current research foci and remaining challenges. We specifically highlight that mass-movements in cold and Polar climates are particularly sensitive to climate change, because of the involvement of permafrost and ice in their triggering and dynamics and therefore we may anticipate an increasing frequency and increased hazard from these phenomena in the future in response to unprecedented rates of environmental change.

The authors would like to acknowledge King Fahd University of Petroleum & Minerals (KFUPM) for supporting this work. This paper proposes a new concept for the evaluation of fatigue damage parameters. It is suggested that evaluation of fatigue damage may not necessarily be confined to a single plane, i.e., a critical plane. Rather, it is suggested here that the culmination of fatigue crack on a particular plane(s) is due to the contributions of damage on all planes. Mathematically, the polar damage sum concept is calculated as the area enclosed by the polar curve of the damage parameter. The proposed concept is examined using multiaxial experimental data for six different alloys. A total of 241 samples are included in this study. Using the proposed concept, fatigue life estimations are improved compared to those obtained from the original critical plane based on Fatemi-Socie and Smith-Watson-Topper models.

Relaxor ferroelectrics are attractive for the high energy storage density. However, the polarization responses of most relaxor ferroelectrics are sensitive to temperature, thus leading to thermal-dependent energy storage properties. In this work, 0.5Bi1/2K1/2TiO3–0.5SrTiO3 (0.5BKT–0.5ST) and 0.95(0.5Bi1/2K1/2TiO3–0.5SrTiO3)–0.05Bi(Zn1/2Ti1/2)O3 (BKT–ST–0.05BZT) ceramics were prepared using the solid-state reaction method. Both compositions showed an average cubic structure, with a relaxor-type dielectric anomaly. The rather low remanent polarization and delayed saturated polarization indicated the formation of the ergodic polar nano regions. Benefitting from the Bi(Zn1/2Ti1/2)O3 modification, the recoverable energy storage density (Wrec) reached 3.07 J/cm3 because of the enhanced polarization and increased bandgap. Meanwhile, BKT–ST–0.05BZT exhibited a high storage efficiency ( η > 88%). When the specimen was heated from 30 °C to 150 °C, Wrec under the maximum electric field Em of 150 kV/cm varied from 1.58 to 1.63 J/cm3 (＜ ±2%).

The surface properties of bio-fibres change by surface plasma treatment without changing their internal properties. In this study, radio-frequency plasma was used to treat the surface of date palm leaves. Plasma treatment was conducted for different times (1, 5, and 8 min) and at different powers (80, 100, and 120 W), keeping the gas pressure fixed at 0.95 torr. Water-drop contact angles, scanning electron-microscope images, surface free-energy measurements, and X-ray diffraction spectra were recorded for the surfaces of the leaves after plasma treatment. Contact-angle values were found to decrease and the surface energy in decrease. The observed changes in surface properties are attributable to a combination of the increase in polar chemical functional groups. Electron micrographs show improvement in the sample surface morphology after plasma treatment. The study showed that the surface modification of fibres by plasma could improve interfacial adhesion between the DPF and an epoxy matrix.

openaire: EC/H2020/|723526/EU//SEDNA Ships operating in ice-infested Arctic waters are exposed to a range of ship-ice interaction related hazards. One of the most dangerous of these is the possibility of a ship becoming beset in ice, meaning that a ship is surrounded by ice preventing it from maneuvering under its own power. Such a besetting event may not only result in severe operational disruption, but also expose a ship to severe ice loading or cause it to drift towards shallow water. This may cause significant structural damage to a ship and potentially jeopardize its safety. To support safe and sustainable Arctic shipping operations, this article presents a probabilistic approach to assess the probability of a ship becoming beset in ice. To this end, the proposed approach combines different types of data, including Automatic Identification System (AIS) data, satellite ice data, as well as data on real-life ship besetting events. Based on this data, using a hierarchical Bayesian model, the proposed approach calculates the probability of a besetting event as a function of the Polar Ship Category of a ship, sea area, and the distance travelled in the prevailing ice concentration. The utility of the proposed approach, e.g. in supporting spatiotemporal risk assessments of Arctic shipping activities as well as Arctic voyage planning, is demonstrated through a case study in which the approach is applied to ships operating in the Northern Sea Route (NSR) area. The outcomes of the case study indicate that the probability of besetting is strongly dependent on the Polar Ship Category of a ship and that the probability increases significantly with higher ice concentrations. The sea area, on the other hand, does not appear to significantly affect the probability of besetting.

Essential oils (EOs) are a complex mixture of different classes of compounds. They are widely applied today in different branches of industry, e.g., food and pharmaceutical industries. EOs are also applied in folk medicine and in the production of perfumes. Because of their significance, it is very important to develop a method for their analysis. To do so, gas chromatography coupled with mass spectrometry (GC/MS) was applied to establish the method. Commonly applied nonpolar column (HP 5-MS) was replaced with the polar one (TR WAX-MS) with polyethylene glycol as a stationary phase. Different analytical standards have been used for the creation of the calibration curves. Results showed that the polar column separated the compound more efficiently than the nonpolar column. The analysis was longer with the polar than with nonpolar column, but the polar stationary phase provided separation based on the polarity of the analyzed compounds, which ensured good separation of isomers and derivatives. To conclude, application of the polar column may provide a better result that is highly desirable, thus its usage for the analysis of EOs is encouraged.

Highly polar pesticides are frequently used in agriculture. However, their physicochemical properties make very difficult the analysis of these compounds following common procedures. Polar pesticides show poor retention and peak shapes in the common stationary phases used for multiresidue methods of pesticides. For this reason, multiple columns with different stationary phases have been developed to perform the analysis of these particular compounds. The column evaluated in this method uses a new hybrid stationary phase with a mixed-mode between hydrophilic interaction liquid chromatography (HILIC) and ion exchange interactions. The retention modes are dependant on mobile phase conditions and can be easily switched. The aim of this study can be summarized in the next bullet points: • Performance evaluation of 10 anionic compounds in different column sizes of the hybrid stationary phase. • Validation of the method in terms of sensitivity, linearity, and matrix effects in four different matrices: tomato, orange, onion and quince. • Improvement of the retention time robustness, Graphical abstract Image, graphical abstract

The proton–proton elastic differential cross section at very small four momentum transfer squared has been measured at three different incident proton momenta in the range of 2.5 to 3.2 GeV/c by detecting the recoil proton at polar angles close to 90∘. The measurement was performed at COSY with the KOALA detector covering the Coulomb–nuclear interference region. The total cross section σtot, which has been determined precisely, is consistent with previous measurements. The values of the slope parameter B and the relative real amplitude ratio ρ determined in this experiment alleviate the lack of data in the relevant energy region. These precise data on ρ might be an important check for a new dispersion analysis.

This study reports the characterization of optical properties of Arctic aerosol and surface snow collected at Ny-Alesund, Svalbard during the polar summer. Methanol-soluble brown carbon (BrC) extracts showed higher absorption coefficients at 300 nm compared to water-soluble BrC and also exhibited a tail of absorption toward higher wavelengths due to the presence of polyconjugated and/or nitroaromatic systems. Fluorescence spectra for water extract for air and snow samples showed peaks at ~340 nm indicating the presence of protein-like fluorophores, possibly from sea-to-air emission of marine organics and secondary formation of aerosols. Air mass back trajectories also suggested the potential contribution of forest fires from Alaska and Russia to BrC aerosol in the Arctic.

We studied phase transitions in new organic ferroelectric DIPAI embedded into porous alumina and in bulk DIPAI. Complex permittivity and third harmonic generation coefficient were measured within a wide temperature range. The increase in the third harmonic generation indicates the emergence of the polar phase. Two phase transitions were seen in bulk DIPAI upon heating from room temperature after preliminary heating up to 420 K while only a transition was found upon cooling accompanied with pronounced thermal hysteresis. The ferroelectric phase was observed in the range between two transitions upon heating and below the transition upon cooling. In contrast, two phase transitions occur in DIPAI confined to porous alumina upon heating and cooling. The transitions do not show noticeable thermal hysteresis. It was suggested that different behavior of bulk and confined DIPAI results from slow kinetics of phase transitions in bulk upon cooling. The noticeable shift of the transition temperatures for DIPAI within alumina pores of different diameters was treated using the theories of size effects in ferroelectrics.

This paper demonstrates the effect of microelectrodes configuration on the sensitivity and accuracy of the micro-electrical impedance spectroscopy (μEIS). Bi-polar and tri-polar microelectrodes configurations were presented, fabricated and experimentally used to extract the electrical parameters of Human Bone Osteosarcoma Epithelial (U2OS) viable and dead cells. A comparison between the experimental results are presented and discussed. These experimental results show that the tri-polar electrode configuration has higher sensitivity compared to bi-polar configuration. Keywords: Bio impedance, U2OS cells, μEIS, Microfluidic platform

Various experimental evidence for the existence of polar sensitivity in crystals is considered: the structural affinity of piezoelectrics and pyroelectrics; the chemical features of polar crystals confirming the proximity of their properties; the increase in volume during self-ordering of the polar-sensitive bonds; the piezoelectric and electrocaloric contributions to permittivity of polar crystals; high-frequency dielectric absorption; the dependence of polar crystal elastic properties on various electrical boundary conditions, etc. Many features of charge transfer in polar-sensitive crystals are explained: the physical nature of the giant change of conductivity in critistors, posistors, and varistors as well as in other field-controllable switching elements, particularly those that exhibit colossal magnetoresistance; the nature of the high sensibility of nanostructured sensors based on zinc oxide is also discussed. The nature of electrically induced polar properties is investigated: electrically induced piezoelectricity in paraelectrics and relaxor ferroelectrics, and electrical control by resonant frequency of piezoelectric resonators and filters. Thermomechanically induced pyroelectricity is examined: an original method of pyroelectric response and volumetric piezoelectric effect, obtained in the polar-neutral piezoelectrics (nonpyroelectrics) is described. Two- and three-dimensional structural arrangements of polar-sensitive bonds in the polar-neutral piezoelectric are analyzed; artificial pyroelectric effects for 10 classes of polar-neutral piezoelectric crystals are calculated and experimentally tested in the quartz and gallium arsenide type crystals. This effect can be used in single-chip pyroelectric and piezoelectric single and matrix sensors.

Particular properties of polar crystals (pyro-, piezo-, and ferroelectrics) are explained by the existence in their structure of peculiar polar-sensitive interatomic bonds, which gives new meaning to the traditional concept of spontaneous polarization. The hybridized ionic-covalent polar bonds originate mainly because of a distinction in the electronegativity of ions forming the polar crystal. Polar bonds cause electrical polarization as a response to nonelectrical homogeneous action (temperature or pressure). If a polar crystal is classified as a ferroelectric, polar-sensitive bonds cause a nonlinear response to an electrical field with a reversal of the orientation. Polar-sensitive structure manifests itself in crystals as the ability to provide electrical (vector type) response to nonelectrical scalar or more complicated tensor types of actions. Hybridized ionic-covalent bonding causes a reduction in crystal symmetry, so polar crystals always belong to the noncentrosymmetric classes. Moreover, it is exactly the presence of such bonds that determines the noncentrosymmetric structure of some crystals. Hybridized ionic-covalent bonding is a main cause of pyroelectric and piezoelectric properties. The model used is based on the asymmetry in the electronic density distribution along the atomic bonds, which ensures the ability of a crystal to demonstrate a polar (electrical) response to nonelectrical action; this model is free from any assumption as to the presence of an internal electrical field in the polar crystal. In some polar crystals, the temperature steadiness of polar-sensitive bonds can be described by the critical law M(T) ~ (θ − T)n, so a phase transition temperature θ exists, at which tensor Mijk vanishes with temperature rise. The critical parameter is n = 1 if polar-sensitive bonds are arranged in a plane (2D case). In the event of a spatial (3D) arrangement of polar-sensitive bonds, the critical exponent is n = 2. These two cases differ from 1D dipole-type polar-sensitive bonds in ferroelectrics, which correspond to the well-known critical law Mi(T) with n = 0.5 (Landau's critical index). The thermodynamics of processes of electrical polarization is also briefly described.

Water environment is conditioning all biological activity. The folding process can not be treated without the active participation of water. The example of the folding process simulation with the influence of water in form of external force field expressed by 3D Gauss function is shown. The concentration of hydrophobic residues in the center of globule with exposure of polar residues on the surface is expected. This model follows the generally accepted model of hydrophobic core to be responsible for tertiary structure stabilisation.

All measures describing the deformation, the rotation, and their rates are defined in terms of the deformation gradient tensor, which is decomposed into the parts standing for the pure deformation and the pure rotation by the polar decondition. The exact measures describing the deformation and the rotation are defined by the parts for the pure deformation and the pure rotation, respectively. They are classified into the Lagrangian and the Eulerian tensors. Various Lagrangian and Eulerian strain tensors and strain rate/spin tensors and their relations that appear in the elastoplasticity theory are described in detail.

This chapter begins with a discussion of the polar array and the steps involved in creating it. Additional operations and the legacy (pre-AutoCAD 2012) polar array are discussed next. Then, we focus on the rectangular array and the steps involved in creating it. Additional operations and the legacy (pre-AutoCAD 2012) rectangular array are discussed next. The chapter concludes with a discussion of the new path array and the steps involved in creating it. The chapter also contains a mechanical project that utilizes the skills acquired in this and the preceding chapters.

Novel A-site deficient (1-x-y)Bi0.5Na0.5TiO3-xBaTiO3-yBi0.2Sr0.7TiO3 lead-free relaxor ferroelectrics have been explored for energy storage property. Particularly slim polarization hysteresis (P-E) loops are observed in 0.655Bi0.5Na0.5TiO3-0.065BaTiO3-0.28Bi0.2Sr0.7□0.1TiO3 (6.5BNBT-BST) at ambient temperature resulting in a giant recoverable energy density (Wrec = 1.5 J cm−3) and extremely high efficiency (η = 90%) at 100 kV cm−1, which are closed related to the track of P-E loops. As the addition of Bi0.2Sr0.7TiO3 (BST) content, the ergodic relaxor phase becomes dominant with dynamic polar nano-regions attributed to the absence of ferroelectric domain in the relaxor phase. Furthermore, the recoverable energy density exhibits small variation in elevated temperature where the depressed polarization is compensated by almost hysteresis free loops (η up to 97%). The achievement of these characteristics in P-E loops provides that Bi0.2Sr0.7TiO3 tailoring by A-site vacancies is a potential route when designing new relaxor ferroelectrics for energy-storage applications. Keywords: Lead-free ceramics, Bi0.5Na0.5TiO3, Energy storage, Efficiency, A-site vacancy

Highlights • Elevated concentrations of surface DPb near South Georgia in the Southern Ocean originated from glacial flour • DPb in the open ocean North Atlantic and Southern Ocean originate from dust particles delivered from Patagonia and Northern Hemisphere • Scavenging of DPb onto biogenic particles formed during spatially confined phytoplankton blooms leads to dissolved Pb removal Abstract Today, four decades past peak anthropogenic lead emissions in the 1970s, dissolved lead (DPb) concentrations in the surface ocean remain elevated. To constrain contemporary sources and sinks of DPb, we studied high latitude surface waters of the North Atlantic and the Southern Ocean. We observed high concentrations of surface DPb (46 pmol kg-1) near South Georgia in the Southern Ocean, sourced from glacial flour, while offshore DPb concentrations of 3–9 pmol kg-1 were attributable to aeolian Pb inputs mainly from Patagonia. Dissolved Pb in the North Atlantic (4–29 pmol kg-1) originated from aeolian particles from Northern Hemisphere sources. Extremely low DPb concentrations of

Selection of suitable ice class for ships operation is an important but not simple task. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards such as Polar Code, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. This paper will analyse what can be the limiting ice thickness for ships navigating in the Russian Arctic and designed according to the Finnish-Swedish ice class rules. The permanent deformations of ice-strengthened shell structures for various ice classes is determined using MT Uikku as the typical size of a vessel navigating in ice. The ice load in various conditions is determined using the ARCDEV data from the winter 1998 as the basic database. By comparing the measured load in various ice conditions with the serviceability limit state of the structures, the limiting ice thickness for various ice classes is determined. The database for maximum loads includes 3-weeks ice load measurements during April 1998 on the Kara Sea mainly by icebreaker assistance. Gumbel 1 distribution is fitted on the measured 20 min maximum values and the data is divided into various classes using ship speed, ice thickness and ice concentration as the main parameters. Results encouragingly show that present designs are safer than assumed in the Polar Code suggesting that assisted operation in Arctic conditions is feasible in rougher conditions than indicated in the Polar Code. Keywords: Loads, Serviceability, Limit ice thickness, Polar code

著者人数: 24名, Accepted: 2016-11-03, 資料番号: SA1170074000

Poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), poly(vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) and poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) were evaluated for the development of ionic liquid (IL) - polymer composite bending actuators. The selected guest IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [Emim][TFSI], was incorporated into the different host polymer matrixes in concentrations ranging from 10 to 40wt%. The IL/polymer composites electrical properties strongly depend on the IL content. The largest bending response was found for the IL/PVDF-TrFE composites with a maximum bending value of 3.5mm using a frequency of 100mHzat an applied potential difference of 5.0 Vpp. Thus, PVDF-TrFE are attractive candidates for the development of high performance bending actuators., Work supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, UID/QUI/00686/2013 and UID/QUI/0686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and Grants SFRH/BD/90215/2012 (J.C.D.), SFRH/BPD/121526/2016 (D.M.C), SFRH/BPD/112547/2015 (C.M.C.), SFRH/BPD/90870/2012 (C.R.). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including the FEDER financial support) and from the Basque Government Industry Department under the ELKARTEK and HAZITEK program and Grupos de Investigación, IT718-13, is also acknowledged., info:eu-repo/semantics/publishedVersion

Ice is a complex material, which has a wide spectrum of properties both temporally and spatially. These properties, in particular, strength, friction, and creep vary with geographical location, age, salinity, temperature, wind, and pressure. In addition, in the northern polar regions of the Earth the ice rotates under the action of wind and gravitational force fields, whereas in the southern latitudes this does not happen to such a marked extent due to the presence of the continental land mass. These aspects, particularly in relation to the fracture and creep of ice, are fundamental to several aspects of marine transportation and offshore structures in the polar regions.

Magnetic properties of new multiferroic BiFe0.5Sc0.5O3 perovskite which exists in two different orthorhombic polymorphs, the antipolar Pnma and the polar Ima2, were studied using a SQUID-magnetometer technique in magnetic fields up to 50 kOe in the temperature range of 5–300 K. Both polymorphs show a weak ferromagnetic component below the Neel temperature, TN∼220 K. A wide cusp-like anomaly of the temperature dependent magnetic susceptibility was revealed below 200 K. The anomaly is dependent on the magnetic field applied and can be associated with the glassy magnetic behavior of the compound. The best fit of the initial magnetization curves taken at each temperature can be obtained as a sum of two contributions, namely the nonlinear in field and the linear one. The nonlinear contribution appeared to be temperature and magnetic field dependent, which is in a good agreement with the magnetization experimentally obtained as a function of temperature in different magnetic fields applied. Increase of external magnetic field leads to a decrease of the nonlinear contribution to the total magnetic moment.

Some classical polar spaces admit polar spaces of the same rank as embedded polar spaces (often arisen as the intersection of the polar space with a non-tangent hyperplane). In this article we look at sets of generators that behave combinatorially as the set of generators of such an embedded polar space, and we prove that they are the set of generators of an embedded polar space.

Hydrophilic interaction chromatography (HILIC) has been fully consolidated as a valuable technique for the effective retention and separation of hydrophilic, polar and ionizable compounds of chemical and biochemical nature.

This paper analyzes how to determine the virial coefficients B and C of real gases by using a theoretical device whose pressures and densities oscillate in chaotic regime. The device is formed by a valve, a pressure controller, a pressure probe and a gas accumulator, for which the thermodynamic model has been derived from the force-mass-energy balances. This model allows keeping the gas temperature almost constant with chaotic oscillations in the inlet to the accumulator. The chaotic data are used to obtain variability in the pressures and densities, so that they can be used as experimental values from which the virial coefficients are estimated. For this purpose, several cubic and high precision equations of state for polar and non-polar gases and mixtures are used. In particular, the virial coefficient B for dry air is estimated by using high precision state equations, whereas, the virial coefficients B and C are also estimated for quantum gases (He4, He3 H2, D2, Ne) by using several modified cubic equations of state at moderate and high pressures. Furthermore, the values for the virial coefficient B obtained from numerical simulations are used to estimate the intermolecular potential and the radial distribution function. The results are in good agreement with the currently known experimental data for virial coefficients published in the literature.

This article gives an overview on the EUMETSAT Polar System (EPS), which is Europe’s contribution to the Polar Meteorological Satellite Observing System. As part of the Initial Joint Polar System (IJPS) it provides data of the atmospheric state, land and ocean surface, cryosphere, and atmospheric composition from eight meteorological instruments on board the Metop satellites, which constitute the space segment of EPS. Three Metop satellites are part of the program and operate in a sun-synchronous mid-morning polar orbit with equator crossing time of 9:30 local solar time (LST), descending node. At least 15 years of operations are foreseen to collect measurements from space which are indispensable for both weather forecasting and climate monitoring. Currently two Metop satellites are in orbit (launched 2006 and 2012).

The feasibility of six ionic liquid- (IL-) based stationary phases for the analysis of environmentally important polychlorinated biphenyls (PCBs) by gas chromatography combined with either electron capture micro-detector (GC-micro-ECD) or quadrupole mass spectrometry (GC–MS, for confirmation) have been evaluated. These IL-based columns showed a separation mechanism different from that observed for other commercial phases, such a low bleed high temperature 8% phenyl (equiv.) polycarborane-siloxane suggested shape-selective phase for non-ortho and mono-ortho-CBs, HT-8, or a polar poly(ethylene glycol), resulting in a different elution order of the 69 investigated PCBs. However, no all phases provided equality satisfactory resolutions for the most environmentally relevant congeners, the 12 toxic and the 7 priority PCBs. From this point of view, the best results were obtained with the SLB-IL76 and SLB-IL59 phases, which showed a number of coelutions for these specific congeners only slightly higher to that observed on HT-8. Interestingly, the SLB-IL59 phase was the only one among the evaluated phases allowing a complete resolution of the most toxic non-ortho substituted congeners # 77, 126 and 169 from all other PCBs investigated. SLB-IL76 and SLB-IL59 also demonstrated a superior chromatographic performance concerning peak symetry, retention time stability and column bleeding, compared to the other four IL-based columns evaluated. Altogether, results obtained for the analysis of pure standards illustrated the potential of, in particular, SLB-IL 59 as an alternative phase for confirmation of the identity of PCBs typically detected in environmental matrices that coeluted on conventional non-polar phases in use for this type of determination. However, the long-term stability and quantitative behaviour of these stationary phases during the analysis of real samples still need to be addressed., AcknowledgementsThe authors thank Sigma-Aldrich for kindly providing someof the ionic liquid phases used in this study. The authors alsothank MINECO (projects CTQ2012-32957 and AGL2016-80475-R7,AEI/FEDER, UE) and Fundación Ramón Areces for financial support.

This chapter describes and discusses the landscape changes in the martian polar and midlatitude regions that are possibly related to the CO2 seasonal cycle. It builds on ideas introduced in Chapter 5 and carries on with the discussion of “exotic” influences on the current landscape evolution of Mars. Geographically, the chapter comprises the southern and northern hemispheres, discussing the similarities and differences in the specific geomorphological features observed in each hemisphere. Among the landscape features and processes discussed are: araneiforms; furrows; high-latitude gullies; alcoves on polar dune alcoves; residual polar scarp avalanches; and polar pits, i.e., “Swiss cheese” terrain.

Anthropogenic contaminants are present in the pristine Arctic mainly due to long-range transport through air and ocean currents. Regional differences in contamination, variation in food web structure, biotransformation processes, age, sex, breeding status, seasonal changes in food availability, and energy needs may all explain variation in contaminant concentrations within and between Arctic marine mammal species. Contaminant effects have mainly been investigated using correlative approaches based on field samples, whereas an increasing number of modeling and in vitro studies have been published during recent years. In polar bears (Ursus maritimus), contaminant exposures have been associated with adverse health effects at the organismal level, from the molecular level, via the physiologic and pathological levels, and indicatively up to the population level, whereas studies on contaminant effects in Arctic seals and whales are scarcer. Decline of the Arctic sea ice is likely to make polar bears more susceptible to contaminant-related effects.

We present analyses of Saturn’s north pole using high-resolution images captured in late 2012 by the Cassini spacecraft’s Imaging Science Subsystem (ISS) camera. The images reveal the presence of an intense cyclonic vortex centered at the north pole. In the red and green visible continuum wavelengths, the north polar region exhibits a cyclonically spiraling cloud morphology extending from the pole to 85°N planetocentric latitude, with a 4700 km radius. Images captured in the methane bands, which sense upper tropospheric haze, show an approximately circular hole in the haze extending up to 1.5° latitude away from the pole. The spiraling morphology and the “eye”-like hole at the center are reminiscent of a terrestrial tropical cyclone. In the System III reference frame (rotation period of 10h39m22.4s, Seidelmann et al. 2007; Archinal et al. 2011), the eastward wind speed increases to about 140 m s^(−1) at 89°N planetocentric latitude. The vorticity is (6.5± 1.5)×10^(−4)s^(−1) at the pole, and decreases to (1.3± 1.2)×10^(−4)s^(−1) at 89°N. In addition, we present an analysis of Saturn’s south polar vortex using images captured in January 2007 to compare its cloud morphology to the north pole. The set of images captured in 2007 includes filters that have not been analyzed before. Images captured in the violet filter (400 nm) also reveal a bright polar cloud. The south polar morphology in 2007 was more smooth and lacked the small clouds apparent around the north pole in 2012. Saturn underwent equinox in August 2009. The 2007 observation captured the pre-equinox south pole, and the 2012 observation captured the post-equinox north pole. Thus, the observed differences between the poles are likely due to seasonal effects. If these differences indeed are caused by seasonal effects, continuing observations of the summer north pole by the Cassini mission should show a formation of a polar cloud that appears bright in short-wavelength filters.

While it is widely accepted that lesions to orbital prefrontal cortex lead to emotion related disruptions and poor decision-making, there is very little patient data on this issue involving actual logical reasoning tasks. We tested patients with circumscribed, focal lesions largely confined to polar/orbital prefrontal cortex (BA 10 & 11) (N=17) on logical reasoning tasks involving neutral and emotional content, and compared their performance to that of an age and education-matched normal control group (N=22) and a posterior lesion control group (N=24). Our results revealed a significant group by content interaction driven by a selective impairment in the polar/orbital prefrontal cortex group compared to healthy normal controls and to the parietal patient group, in the emotional content reasoning trials. Subsequent analyses of congruent and incongruent reasoning trials indicated that this impairment was driven by the poor performance of patients with polar/orbital lesions in the incongruent trials. We conclude that the polar/orbital prefrontal cortex plays a critical role in filtering emotionally charged content from the material before it is passed on to the reasoning system in lateral/dorsal regions of prefrontal cortex. Where unfiltered content is passed to the reasoning engine, either as a result of pathology (as in the case of our patients) or as a result of individual differences, reasoning performance suffers.

Source at https://doi.org/10.1111/1365-2656.12685. Accepted manuscript version, licensed CC BY-NC-ND 4.0. 1. Climate change is impacting different species at different rates, leading to alterations in biological interactions with ramifications for wider ecosystem functioning. Understanding these alterations can help improve predictive capacity and inform management efforts designed to mitigate against negative impacts. 2. We investigated how the movement and space use patterns of polar bears (Ursus maritimus) in coastal areas in Svalbard, Norway, have been altered by a sudden decline in sea ice that occurred in 2006. We also investigated whether the spatial overlap between polar bears and their traditionally most important prey, ringed seals (Pusa hispida), has been affected by the sea‐ice decline, as polar bears are dependent on a sea‐ice platform for hunting seals. 3. We attached biotelemetry devices to ringed seals (n = 60, both sexes) and polar bears (n = 67, all females) before (2002–2004) and after (2010–2013) a sudden decline in sea ice in Svalbard. We used linear mixed‐effects models to evaluate the association of these species to environmental features and an approach based on Time Spent in Area to investigate changes in spatial overlap between the two species. 4. Following the sea‐ice reduction, polar bears spent the same amount of time close to tidal glacier fronts in the spring but less time in these areas during the summer and autumn. However, ringed seals did not alter their association with glacier fronts during summer, leading to a major decrease in spatial overlap values between these species in Svalbard's coastal areas. Polar bears now move greater distances daily and spend more time close to ground‐nesting bird colonies, where bear predation can have substantial local effects. 5. Our results indicate that sea‐ice declines have impacted the degree of spatial overlap and hence the strength of the predator–prey relationship between polar bears and ringed seals, with consequences for the wider Arctic marine and terrestrial ecosystems. Shifts in ecological interactions are likely to become more widespread in many ecosystems as both predators and prey respond to changing environmental conditions induced by global warming, highlighting the importance of multi‐species studies.

In this chapter, we discuss the influence of molecular association on compositional grading of oil and gas reservoirs. This phenomenon, of which the hydrogen bonding is one of the main examples, is characterized by strong short-range attractive interactions and is intimately related to the polarity of fluid molecules. The angular orientation of the polar sites in a group of molecules and the short distance between them are crucial for the attractive potential around these areas to allow its association, which presents characteristics very similar to a strong (but not permanent) chemical bond.

Polar stationary phases are used in separations with several retention mechanisms, such as hydrophilic interaction chromatography (HILIC), normal-phase chromatography (NPC), and aqueous normal-phase chromatography (ANPC or ANP). The HILIC columns are classified in several main types: bare silica, neutral anion exchange, cation exchange, zwitterionic, and mixed polar and hydrophobic. Some examples of methods for polar stationary phase preparation are given. This chapter presents some aspects useful in the selection of polar analytical columns, such as column physical and chemical properties and the retention and separation capability. Several parameters and tests for HILIC column characterization are also presented. Information on the main commercial polar analytical columns can be found in Appendix 3 .

Permittivity and relaxation times of binary polar liquid mixtures contain information regarding many body molecular interactions in liquid. Qualitative information regarding these interactions can be estimated through excess properties, effective Kirkwood correlation factors, and the modified Bruggeman parameter. These properties do not provide any quantitative information regarding the formation of multimers in the mixture due to nonavailability of a suitable theoretical model. The Luzar model that is applicable to the only formation of only three types of pairs provides more details from the values of static permittivity. Some examples related to the Luzar model are given in the chapter. However, no similar theory is available for relaxation time.

This chapter contains the experimental values of dielectric relaxation parameters of associative and nonassociative polar liquids with chloro and nitro groups over the entire concentration range. The dielectric relaxation measurements of binary mixtures have been carried out at different temperatures using the time domain reflectometry technique. The associative liquids used were alcohols and amides. The dielectric relaxation for chlorobenzene, 1,2-dichloroethane, dimethylene chloride, nitrobenzene, nitrotoluene, 2-nitrotoluene and 2-nitroacetophenone, formamide, N -methylformamide, N , N -dimethylacetamide, N , N -dimethylformamide, and dimethylsulfoxide have been studied using the time domain reflectometry technique. The Kirkwood correlation factor, excess dielectric constant, excess relaxation properties, and thermodynamic and Bruggeman parameters have been reported in this chapter. The comparison of dielectric parameter reveals the marked influence of hydrogen bonding on the structure and dynamics of these polar associative liquids. The Kirkwood correlation factor increases with an increase in the molecular size of the liquid but decreases with increasing temperature.