Journal articles on the topic 'Quasi-flat objects'

We define the projective stable category of a coherent scheme. It is the homotopy category of an abelian model structure on the category of unbounded chain complexes of quasi-coherent sheaves. We study the cofibrant objects of this model structure, which are certain complexes of flat quasi-coherent sheaves satisfying a special acyclicity condition.

We have made a polarimetric survey of 84 quasi-stellar objects, to supplement published polarization measurements for two samples of quasars identified with flat-spectrum (core-dominant) radio sources in 5 GHz surveys made at Bonn (Kühr 1980) and at the VLA (Perley 1982). The observations were made using the McDonald 2.1m Struve reflector and the polarimeter described by Breger (1979); the typical accuracy is 0.5% for an 18 mag object after half an hour. Earlier surveys, such as those by Stockman, Moore and Angel (1984), included objects of various radio spectral types, and only a small fraction of the objects showed high polarization (> 3%), but our sample of flat-spectrum quasars reveals many more (about half) of the objects to be highly polarized. Some of them are, expectedly, of the BL Lac class, but many of them have strong broad emission lines. There are two striking correlations among the results: (1)The degree of polarization is strongly correlated with the dominance of the radio core - specifically, with the ratio, R, of core to lobe luminosity (Fig. 1). For example, about 75% of the objects with log R > 1.25 and redshift z < 1 have p > 3%. This relation implies that if the radio core radiation is beamed, as seems likely, then so is the optical synchrotron component.(2)The fraction of objects with p > 3% is inversely correlated with redshift (e.g. Fig. 2). The most likely interpretation of this result is that quasars' degree of polarization decreases with decreasing rest wavelength, and the shorter wavelengths are shifted into our wide observational passband at higher redshifts.

Let [Formula: see text] be a symmetric monoidal closed exact category. This category is a natural framework to define the notions of purity and flatness. When [Formula: see text] is endowed with an injective cogenerator with respect to the exact structure, we show that an object [Formula: see text] in [Formula: see text] is flat if and only if any conflation ending in [Formula: see text] is pure. Furthermore, we prove a generalization of the Lambek Theorem (J. Lambek, A module is flat if and only if its character module is injective, Canad. Math. Bull. 7 (1964) 237–243) in [Formula: see text]. In the case [Formula: see text] is a quasi-abelian category, we prove that [Formula: see text] has enough pure injective objects.

Flat objects lying on a surface are hard to grasp, but could be manipulated by sliding along the surface in a non-prehensile manner. This strategy is commonly employed by humans as pre-manipulation, for example to bring a cell phone to the edge of a table to pick it up. To endow robots with a similar capability, we introduce a mathematical model of planar sliding by means of a soft finger. The model reveals various aspects of interaction through frictional contacts, which can be used for planning and control. Specifically, using a quasi-static analysis we are able to derive a hybrid dynamical system to predict the motion of the object and the interaction forces. The conditions for which the object sticks to the friction patch, pivots, or completely slides against it are obtained. It is possible to find fixed points of the system and the path taken by the object to reach such configurations. Theoretical as well as comprehensive experimental results are presented.

The study of prevalent orbits in galactic subsystems can help us understand galactic structure and clarify its history. The classical analysis of flat orbits and metallicities of old stars led Eggen et al. (1962) to formulate the rapid collapse of the primordial Galaxy. On the other side Yoshii & Saio (1979) studied three-dimensional orbits that separate in spherical coordinates. They found the Galaxy contracted quasi-stationary after the formation of halo objects. Here we shall briefly discuss the results of numerical orbit calculations (with Merson's method) for selected galactic subsystems. The axially symmetrical two-component model of the Galaxy (Kutuzov, Ossipkov 1989) was adopted. One-component models (Barkhatova et al. 1987, Kutuzov 1988) were used also but no significant difference in orbit elements was found (Kutuzov & Ossipkov 1992). Pericenter and apocenter distances, Rp and Ra, and the maximal height of objects over the galactic plane, zm, were used as orbit elements as well as dimensionless quantities e = (Ra — Rp)/(Ra + Rp) (eccentricity) and c = 2zm/(Ra — Rp) (the flatness of box filled by orbit projection on the meridional plane).

Starting from the concept of invariant KAM tori for nearly-integrable Hamiltonian systems with periodic or quasi-periodic nonautonomous perturbation, the paper analyzes the “analogue” of this class of invariant objects when the dependence on time is aperiodic. The investigation is carried out in a model motivated by the problem of a traveling wave in a channel over a smooth, quasi- and asymptotically flat (from which the “transient” feature) bathymetry, representing a case in which the described structures play the role of barriers to fluid transport in phase space. The paper provides computational evidence for the existence of transient structures also for “large” values of the perturbation size, as a complement to the rigorous results already proven by the first author for real-analytic bathymetry functions.

In this paper is provided mathematical analysis related to a particular case for a point quasi-rotation around a curve of an elliptical axis. The research complements the previous works in this direction. Has been considered a special case, in which the quasi-rotation correspondence is applied to a point located at the elliptical axis’s focus. This case is special, since the quasi-rotation center search is not invariant and does not lead to determination of four quasi-rotation centers, as in the general case. A constructive approach to the rotation center search shows that any point lying on the elliptical axis can be the quasi-rotation center. This feature leads to the fact that instead of four circles, the quasi-rotation of a point lying in the elliptical axis’s focus leads to the formation of an infinite number of circle families, which together form a channel surface. The resulting surface is a Dupin cyclide, whose throat circle has a zero radius and coincides with the original generating point. While analyzing are considered all cases of the rotation center location. Geometric constructions have been performed based on previously described methods of rotation around flat geometric objects’ curvilinear axes. For the study, the mathematical relationship between the coordinates of the initial set point, the axis curve equation and the motion trajectory equation of this point around the axis curve, described in earlier papers on this topic, is used. In the proposed paper has been provided the derivation of the motion trajectory equation for a point around the elliptic axis’s curve.

The non-pneumatic tire (NPT) is a type of wheel whichdevelopment is related to the beginning of automotive development. The non-pneumatic tire (NPT) is a type of tire that does not contain compressed gases or fluid to provide directional control and traction. Nowadays, this type of wheel is more and more often used in special purpose vehicles, e.g., in military vehicles and working machines. The main feature of the non-pneumatic tire is a flexible support structure (including the part of the wheel between the tread and the rim). This paper presents the results of research aimed at determining the influence of the geometry of the NPT’s (intended for All-Terrain Vehicle–ATV/Utility Task Vehicle–UTV) load-bearing structure on its quasi-static directional characteristics. The experimental tests included the determination of the radial stiffness of research objects on a non-deformable flat surface and on a single obstacle, as well as the determination of the degree of deformation for the elastic structure and belt. The significant influence of the elastic structure’s shape and the elastomer, as the material forming the NPT, on its radial stiffness was revealed.

We prove that quasi-static pushing with a sticking contact and ellipsoid approximation of the limit surface is differential flat. Both graphical and algebraic derivations are given. A major conclusion is that the pusher–slider system is reducible to the Dubins car problem where the sticking contact constraints translate to bounded curvature. Planning is as easy as computing a Dubins curve with the additional benefit of time-optimality. For trajectory stabilization, we design closed-loop control using dynamic feedback linearization or open-loop control using two contact points as a form of mechanical feedback. We conduct robotic experiments using objects with different pressure distributions, shape, and contact materials placed at different initial poses that require difficult switching action maneuvers to the goal pose. The average error is within 1.67 mm in translation and 0.5° in orientation over 60 experimental trials. We also show an example of pushing among obstacles using a RRT planner with exact steering.

We compile from literature the broadband SEDs of twelve TeV blazars observed simultaneously or quasi-simultaneously with Fermi/LAT and other instruments. Two SEDs are available for each of the objects and the state is identified as a low or high state according to its flux density at GeV/TeV band. The observed SEDs of BL Lac objects (BL Lacs) are fitted well with the synchrotron + synchrotron-self-Compton (syn+SSC) model, whereas the SEDs of the two flat spectrum radio quasars (FSRQs) need to include the contributions of external Compton scattering. In this scenario, it is found that the Doppler factor δ of FSRQs is smaller than that of BL Lacs, but the magnetic field strength B of FSRQs is larger than that of BL Lacs. The increase of the peak frequency of the SEDs is accompanied with the increase of the flux for the individual sources, which seems opposite to the observational phenomena of the blazar sequence. We refer this phenomenonto blazar anti-sequence of spectral variability for individual TeV blazars. However, both the blazar sequence from FSRQs to BL Lacs and blazar anti-sequence of the spectral variability from low state to high state are accompanied by an increase of the break Lorentz factor of the electron's spectrum γ b and a decrease of B. We propose a model in which the mass accretion rate Ṁ is the driving force behind both the blazar sequence for ensembles of blazars and the blazar anti-sequence for individual blazars. Specifically we suggest that the differences in 〈Ṁ〉 of different blazars produce the observed blazar sequence, but ΔṀ in each blazar results in the observed blazar anti-sequence.

The horizontal variation and vertical layering of the vegetation are important properties of the canopy structure determining the habitat; three-dimensional (3D) distribution of objects (shrub layers, understory vegetation, etc.) is related to the environmental factors (e.g., illumination, visibility). It has been shown that gaps in forests, mosaic-like structures are essential to biodiversity; various methods have been introduced to quantify this property. As the distribution of gaps in the vegetation is a multi-scale phenomenon, in order to capture it in its entirety, scale-independent methods are preferred; one of these is the calculation of lacunarity. &lt;br&gt;&lt;br&gt; We used Airborne Laser Scanning point clouds measured over a forest plantation situated in a former floodplain. The flat topographic relief ensured that the tree growth is independent of the topographic effects. The tree pattern in the plantation crops provided various quasi-regular and irregular patterns, as well as various ages of the stands. The point clouds were voxelized and layers of voxels were considered as images for two-dimensional input. These images calculated for a certain vicinity of reference points were taken as images for the computation of lacunarity curves, providing a stack of lacunarity curves for each reference points. These sets of curves have been compared to reveal spatial changes of this property. As the dynamic range of the lacunarity values is very large, the natural logarithms of the values were considered. Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.

The horizontal variation and vertical layering of the vegetation are important properties of the canopy structure determining the habitat; three-dimensional (3D) distribution of objects (shrub layers, understory vegetation, etc.) is related to the environmental factors (e.g., illumination, visibility). It has been shown that gaps in forests, mosaic-like structures are essential to biodiversity; various methods have been introduced to quantify this property. As the distribution of gaps in the vegetation is a multi-scale phenomenon, in order to capture it in its entirety, scale-independent methods are preferred; one of these is the calculation of lacunarity. <br><br> We used Airborne Laser Scanning point clouds measured over a forest plantation situated in a former floodplain. The flat topographic relief ensured that the tree growth is independent of the topographic effects. The tree pattern in the plantation crops provided various quasi-regular and irregular patterns, as well as various ages of the stands. The point clouds were voxelized and layers of voxels were considered as images for two-dimensional input. These images calculated for a certain vicinity of reference points were taken as images for the computation of lacunarity curves, providing a stack of lacunarity curves for each reference points. These sets of curves have been compared to reveal spatial changes of this property. As the dynamic range of the lacunarity values is very large, the natural logarithms of the values were considered. Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.

The object of the present paper is to characterize quasi-conformally flat and $\xi$-quasi-conformally flat almost Kenmotsu manifolds with $(k,\mu)$-nullity and $(k,\mu)'$-nullity distributions respectively. Also we characterize almost Kenmotsu manifolds with vanishing extended quasi-conformal curvature tensor and extended $\xi$-quasi-conformally flat almost Kenmotsu manifolds such that the characteristic vector field $\xi$ belongs to the $(k,\mu)$-nullity distribution.

The concept of visuality proposed by Norman Bryson, which refers to conscious perception determined by a system of concepts and knowledge of the visible, is related in the paper to the relationship between two kinds and ideas of photography, introduced respectively by Louis J. Daguerre and William H. Fox Talbot. The discourse about daguerrotypy stresses the quasi-telescopic properties of the picture whose visually ungraspable surface triggers an effect of reaching with the eye far beyond it toward even the farthest details, invisible without a looking glass but still clearly visible in the picture. In response to this feature, Talbot connected the photographic picture primarily with the effects of transferring the relations of shadow and light to contrast on the surface of photosensitive paper. He referred the “photogenic drawing” to a tradition older than the Albertian paradigm of the illusion of perspective adopted by Daguerre in his famous views of the streets of Paris from the window. His technique, called “skiagraphy,” Talbot associated with an ancient legend about the origin of drawing as the art of fixing shadows on a flat surface. His photographs of Lacock Abbey windows were a paradigmatic example that determined the understanding of each photo on the level of its basic self-reflexive content: in the first place, the photographic picture shows how reality before the camera lens projects its “skiagraphic” drawing – a “stamp,” as it were – on the paper surface, and how the forms of objects are reduced to that surface and grasped on it. In his Pencil of Nature, Talbot connected photographic pictures with text, determining the visual status of print photography as replica – both repetition of the highly appreciated daguerrotypy, and a rival response to it, showing the advantages of Calotypy based on the visible proximity of the picture and the surface. Thanks to the properties of Calotypy, precise “fixing of shadows” allows one to arrest despite the flow of time and fix in a visual structure what is the most volatile and changeable.

An analysis of the process of thermal modification of wood, which was obtained by a controlled heating process, was done. The unique technological properties (durability, low hygroscopicity and dimensional stability) of thermomodified wood make it possible to use it in various scope. Due to the influence of temperature there are some chemical changes in the structures of the wood cell wall components (lignin, cellulose and hemicellulose). This leads to an increase in density, hardness, improved hydrophobicity (water repellency), thereby reducing their ability to absorb moisture and swell. The products absorb moisture gradually, are less prone to swelling and shrinkage, but still need the elastic coatings application. It is proved that heat-treated wood turns gray over time under the influence of sunlight, and therefore requires additional surface treatment with a coating. Additional protective substances application on the thermo-modified wood products surface promotes dimensional stability and protects against rapid weathering of the surface in open air conditions. The use of transparent coatings and oils does not protect the surface from discoloration during weathering. They are recommended for products are manufactured from thermomodified wood, which are operated away from direct sunlight and rain. The parameters of moisture penetration into wood are mathematically modeled on the basis of the moisture diffusion quasi-stationary equation through the polymer coating on the flat sample surface. The dynamics of moisture content changes in thermally modified wood by different schedules parameters has been experimentally studied. The obtained mathematical relations based on the experimental studies results make it possible to calculate the moisture diffusion coefficient in thermally modified wood in the presence of a polymer shell. It is established that the wax coating application on the surface of the product reduces the moisture diffusion process more than 10 times for surfaces treated at a temperature of 160 °C for 1 hour. That is, such products can be used on objects with high humidity.

The object of this paper is to study K-contact manifold with quasi-conformal curvature tensor. We find some interesting results for a quasi conformally flat K-contact manifold under certain conditions. In particular it is proved that a K-contact manifold with the condition. ˜ C.S = 0 is η− Einstein.

The object of the present paper is to introduce a type of non-flat Riemannian man- ifold called pseudo generalized quasi-Einstein manifold and studied some properties of such a manifold with several non-trivial examples.

The object of the present paper is to introduce a type of non-flat Riemannian manifold called pseudo cyclic Ricci symmetric manifold and study its geometric properties. Among others it is shown that a pseudo cyclic Ricci symmetric manifold is a special type of quasi-Einstein manifold. In this paper we also study conformally flat pseudo cyclic Ricci symmetric manifolds and prove that such a manifold can be isometrically immersed in a Euclidean manifold as a hypersurface.

AbstractWe theoretically investigate the illusion device designed by a conformal transformation that can render an elliptic defect behave like a flat mirror. Different from illusion devices consisting of the complementary medium and anti-object with negative permittivity and permeability, our proposed illusion device requires only isotropic positive permittivity medium. It offers a possible route to eliminate the lateral shift in the conventional quasi-conformal carpet cloak. Interestingly, with the same conformal transformation, we can achieve an impedance-matched flat absorber by simply varying the shape and the refractive index of the defects. Both the illumination device and the absorber in our design have broad bandwidth, wide-illumination range and polarization-insensitive performance.

ABSTRACT We report on quasi-periodic variability found in two blazars included in the Steward Observatory Blazar Monitoring data sample: the BL Lac object 3C 66A and the Flat Spectrum Radio Quasar B2 1633+38. We collect optical photometric and polarimetric data in V and R bands of these sources from different observatories: St. Petersburg University, Crimean Astrophysical Observatory, WEBT–GASP, Catalina Real-Time Transient Survey, Steward Observatory, STELLA Robotic Observatory, and Katzman Automatic Imaging Telescope. In addition, an analysis of the γ-ray light curves from Fermi–LAT is included. Three methods are used to search for any periodic behaviour in the data: the Z-transform Discrete Correlation Function, the Lomb–Scargle periodogram and the Weighted Wavelet Z-transform. We find pieces of evidence of possible quasi-periodic variability in the optical photometric data of both sources with periods of ∼3 yr for 3C 66A and ∼1.9 yr for B2 1633+38, with significances between 3σ and 5σ. Only B2 1633+38 shows evidence of this behaviour in the optical polarized data set at a confidence level of 2σ–4σ. This is the first reported evidence of quasi-periodic behaviour in the optical light curve of B2 1633+38. Also, a hint of quasi-periodic behaviour is found in the γ-ray light curve of B2 1633+38 with a confidence level ≥2σ, while no periodicity is observed for 3C 66A in this energy range. We propose different jet emission models that could explain the quasi-periodic variability and the differences found between these two sources.

This paper describes the design considerations, integration issues, packaging, and experimental performance of recently developed D-Band dual-channel transceiver with on-chip antennas fabricated in a SiGe-BiCMOS technology. The design comprises a fully integrated transceiver circuit with quasi-monostatic architecture that operates between 114 and 124 GHz. All analog building blocks are controllable via a serial peripheral interface to reduce the number of connections and facilitate the communication between digital processor and analog building blocks. The two electromagnetically coupled patch antennas are placed on the top of the die with 8.6 dBi gain and have a simulated efficiency of 60%. The chip consumes 450 mW and is wire-bonded into an open-lid 5 × 5 mm2quad-flat no-leads package. Measurement results for the estimation of range, and azimuth angle in single object situation are presented.

The article considers the development of software for information processing in an assisting robotic-technical system. The goal of the article is to synthesize a set of algorithms which allow transforming a digital cube in correspondence with its compression and stretching at any angle to the surface with a given force, as well as visualizing the transformation results in a volumetric form and any flat section. The paper describes the solution of several problems - generating 3D-image in the form of a digital cube with the possibility of its stratification along a discrete mesh. The authors also present the development of algorithms for transforming a digital cube. As a result, an assisting robotic system, a software module for transforming and visualizing the quasi-cube of a virtual object were designed and further development directions of the system were identified.

The object of the present paper is to study mixed quasi-Einstein spacetimes, briefly M(QE)4 spacetimes. First we prove that every Z Ricci pseudosymmetric M(QE)4 spacetimes is a Z Ricci semisymmetric spacetime. Then we study Z flat spacetimes. Also we consider Ricci symmetric M(QE)4 spacetimes and among others we prove that the local cosmological structure of a Ricci symmetricM(QE)4 perfect fluid spacetime can be identified as Petrov type I, DorO. We show that such a spacetime is the Robertson-Walker spacetime. Moreover we deal with mixed quasi-Einstein spacetimes with the associated generators U and V as concurrent vector fields. As a consequence we obtain some important theorems. Among others it is shown that a perfect fluid M(QE)4 spacetime of non zero scalar curvature with the basic vector field of spacetime as velocity vector field of the fluid is of Segr?e characteristic [(1,1,1),1]. Also we prove that a M(QE)4 spacetime can not admit heat flux provided the smooth function b is not equal to the cosmological constant k. This means that such a spacetime describe a universe which has already attained thermal equilibrium. Finally, we construct a non-trivial Lorentzian metric of M(QE)4.

This work analyzes the possibility of a provision of force-majeure mode of the combat vehicles with the aid of disk construction installed in the baffler, the base of the operation of which is the method of residual cyclical quadratic chain code of construction of the “windows” of the movable disk. To determine the optimal parameters of the moving disk of the rotor system, mathematical modeling was performed. The results of mathematical modeling were used to create a PC-based calculation program. The calculation was performed for the rotational frequency ω = 300 s−1 andfor harmonic numbers from 1 to 100. The waveforms used in simulation were as follows: quasi-trapezoidal and rectangular. It is established that at the number of “windows” m = 276 in the moving disk of the rotor system the radiation spectrum acquires a uniform distribution. The object of the research is the process of extreme burning of fuel material in the combat vehicles’ engines, ensuring, according to the technical possibilities of the engine, the implementation of the force-majeure mode of the combat vehicle in the whole. The quantitative and qualitative criteria of fullness of fuel material burning in the engine are chosen as the basis for the evaluation of the reaching of the force-majeure mode. The “flat noise” of the efflux is chosen as the basis of this evaluation. This method ensures the construction of the stochastic structure of “flat noise” in the engine efflux and, in that way, confirms the possibility of technical implementation of the force-majeure mode. The rotor system further ensures not only the force-majeure formation, but also reaches the minimum noise of the combat vehicle at the change of its dislocation. The research results can be further used to optimize the design of exhaust systems, which will reduce emissions.

In this paper is provided mathematical analysis related to a particular case for a point quasi-rotation around a curve of an elliptical axis. The research complements the previous works in this direction. Has been considered a special case, in which the quasi-rotation correspondence is applied to a point located at the elliptical axis’s focus. This case is special, since the quasi-rotation center search is not invariant and does not lead to determination of four quasi-rotation centers, as in the general case. A constructive approach to the rotation center search shows that any point lying on the elliptical axis can be the quasi-rotation center. This feature leads to the fact that instead of four circles, the quasi-rotation of a point lying in the elliptical axis’s focus leads to the formation of an infinite number of circle families, which together form a channel surface. The resulting surface is a Dupin cyclide, whose throat circle has a zero radius and coincides with the original generating point. While analyzing are considered all cases of the rotation center location. Geometric constructions have been performed based on previously described methods of rotation around flat geometric objects’ curvilinear axes. For the study, the mathematical relationship between the coordinates of the initial set point, the axis curve equation and the motion trajectory equation of this point around the axis curve, described in earlier papers on this topic, is used. In the proposed paper has been provided the derivation of the motion trajectory equation for a point around the elliptic axis’s curve.

The titanium alloys are the objects of wide experimental analysis in the terms of crack growth characteristics and mechanism of fracture due to their applications. The Ti-6.4%Al-2.6%Mo-1.7%Cr-0.5%Fe-0.5%Si (wt %) alloy was used in the investigation. The tensile tests were conducted on plate specimens. The test variables considered are width of tensile specimen, crack size and tensile loading. The mechanism of fracture that appeared in the specimens was established from the TEM micrographs of the replicas taken from different zones of the fracture surfaces. The mechanism of fracture was also studied using finite element analysis. The results obtained from the FEA were verified with experimental results. It can be concluded that there is a general trend of increasing stress intensity factor with increasing applied tensile load, crack size and width of the flat specimen. The strain energy release increases with increasing applied tensile load. Crack extension can occur when crack-driving force is equal to the energy required for crack growth. For a particular stress the energy release rate is proportional to the crack size. As the tensile load and the size of the initial crack increase, there is an increased crack growth in the Ti alloy. In the crack initiation zone evidence of quasi-cleavage fracture with limited plastic striations symptoms was found in the specimen tested under  =1000MPa. Micro fracture analysis of the specimens (tested under =1100MPa) has revealed quasi-cleavage fracture with small symptoms of plastic shearing in the early part of cracking.

AbstractConventional optical imaging systems cannot resolve the features smaller than approximately half the size of the working wavelength, called the diffraction limit. The superlens theory predicts that a flat lens made of an ideal material with negative permittivity and/or permeability is able to resolve features much smaller than working wavelength through the restoration of evanescent waves. We experimentally demonstrated the superlens concept for the first time using a thin silver slab in a quasi-static regime; a 60nm half-pitch object was imaged with 365nm illumination wavelength, λ/6 resolution, and the imaging of 50nm half-pitch object under the same light source, λ/7, was also reported. Here, we present mainly experimental studies of near-field optical superlens imaging.

The widely used infrared imaging control of bolted connections in live rectangular buses is performed without direct access to the object being diagnosed. This gives only an approximate idea of the contact state, whereas the contact layer condition remains poorly known. The high thermal conductivity of the live bus material makes the thermal field pattern near the contact connection rather soft, which significantly adds complexity to the diagnostics. Therefore, it is important to develop diagnostics of contact connections by dynamic methods based on analyzing the thermal effect of rectangular test or quasi-rectangular operational current pulses in the busbars of electrical installations. By analyzing the temperature field dynamics in the flat contact zone it becomes possible to establish a functional relationship between the contact zone temperature and the bus free surface temperature, and also the relationship between the temperature recorded on the bus surface and the transition resistance, which is the contact quality characteristic. It has been shown, by simulating the contact surface temperature control in the dynamic monitoring mode, that it is possible to determine the rectangular bus bolted connection overheating protection response time. It is proposed to use the obtained dependence as a conversion function for an intelligent electrical contact temperature sensor.

AbstractConventional imaging and recognition systems require an extensive amount of data storage, pre-processing, and chip-to-chip communications as well as aberration-proof light focusing with multiple lenses for recognizing an object from massive optical inputs. This is because separate chips (i.e., flat image sensor array, memory device, and CPU) in conjunction with complicated optics should capture, store, and process massive image information independently. In contrast, human vision employs a highly efficient imaging and recognition process. Here, inspired by the human visual recognition system, we present a novel imaging device for efficient image acquisition and data pre-processing by conferring the neuromorphic data processing function on a curved image sensor array. The curved neuromorphic image sensor array is based on a heterostructure of MoS2 and poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane). The curved neuromorphic image sensor array features photon-triggered synaptic plasticity owing to its quasi-linear time-dependent photocurrent generation and prolonged photocurrent decay, originated from charge trapping in the MoS2-organic vertical stack. The curved neuromorphic image sensor array integrated with a plano-convex lens derives a pre-processed image from a set of noisy optical inputs without redundant data storage, processing, and communications as well as without complex optics. The proposed imaging device can substantially improve efficiency of the image acquisition and recognition process, a step forward to the next generation machine vision.

Abstract There has recently been a strong revival of interest in quasi-extremal magnetically charged black holes. In the asymptotically flat case, it is possible to choose the magnetic charge of such an object in such a manner that the black hole is surrounded by a corona in which electroweak symmetry is restored on macroscopic scales, a result of very considerable interest. We argue that holographic duality indicates that the asymptotically AdS analogues of these black holes have several interesting properties: the dual theory is only physical if the black hole is required to rotate; in the rotating case, the magnetic field at the poles does not attain its maximum on the event horizon, but rather somewhat outside it; the magnetic field at the equator is not a monotonically decreasing function of the magnetic charge; the electric fields induced by the rotation, while smaller than their magnetic counterparts, are by no means negligible; the maximal electric field often occurs neither at the poles nor at the equator; and so on. Most importantly, in the magnetically charged case it is possible to avoid the superradiant instability to which neutral AdS-Kerr black holes are subject; but the need to avoid this instability imposes upper bounds on the magnetic and electric fields. In some circumstances, therefore, the corona may not exist in the asymptotically AdS case.

When George Orwell encountered ideas of a technological utopia sixty-five years ago, he acted the grumpy middle-aged man Reading recently a batch of rather shallowly optimistic “progressive” books, I was struck by the automatic way in which people go on repeating certain phrases which were fashionable before 1914. Two great favourites are “the abolition of distance” and “the disappearance of frontiers”. I do not know how often I have met with the statements that “the aeroplane and the radio have abolished distance” and “all parts of the world are now interdependent” (1944). It is worth revisiting the old boy’s grumpiness, because the rhetoric he so niftily skewers continues in our own time. Facebook features “Peace on Facebook” and even claims that it can “decrease world conflict” through inter-cultural communication. Twitter has announced itself as “a triumph of humanity” (“A Cyber-House” 61). Queue George. In between Orwell and latter-day hoody cybertarians, a whole host of excitable public intellectuals announced the impending end of materiality through emergent media forms. Marshall McLuhan, Neil Postman, Daniel Bell, Ithiel de Sola Pool, George Gilder, Alvin Toffler—the list of 1960s futurists goes on and on. And this wasn’t just a matter of punditry: the OECD decreed the coming of the “information society” in 1975 and the European Union (EU) followed suit in 1979, while IBM merrily declared an “information age” in 1977. Bell theorized this technological utopia as post-ideological, because class would cease to matter (Mattelart). Polluting industries seemingly no longer represented the dynamic core of industrial capitalism; instead, market dynamism radiated from a networked, intellectual core of creative and informational activities. The new information and knowledge-based economies would rescue First World hegemony from an “insurgent world” that lurked within as well as beyond itself (Schiller). Orwell’s others and the Cold-War futurists propagated one of the most destructive myths shaping both public debate and scholarly studies of the media, culture, and communication. They convinced generations of analysts, activists, and arrivistes that the promises and problems of the media could be understood via metaphors of the environment, and that the media were weightless and virtual. The famous medium they wished us to see as the message —a substance as vital to our wellbeing as air, water, and soil—turned out to be no such thing. Today’s cybertarians inherit their anti-Marxist, anti-materialist positions, as a casual glance at any new media journal, culture-industry magazine, or bourgeois press outlet discloses. The media are undoubtedly important instruments of social cohesion and fragmentation, political power and dissent, democracy and demagoguery, and other fraught extensions of human consciousness. But talk of media systems as equivalent to physical ecosystems—fashionable among marketers and media scholars alike—is predicated on the notion that they are environmentally benign technologies. This has never been true, from the beginnings of print to today’s cloud-covered computing. Our new book Greening the Media focuses on the environmental impact of the media—the myriad ways that media technology consumes, despoils, and wastes natural resources. We introduce ideas, stories, and facts that have been marginal or absent from popular, academic, and professional histories of media technology. Throughout, ecological issues have been at the core of our work and we immodestly think the same should apply to media communications, and cultural studies more generally. We recognize that those fields have contributed valuable research and teaching that address environmental questions. For instance, there is an abundant literature on representations of the environment in cinema, how to communicate environmental messages successfully, and press coverage of climate change. That’s not enough. You may already know that media technologies contain toxic substances. You may have signed an on-line petition protesting the hazardous and oppressive conditions under which workers assemble cell phones and computers. But you may be startled, as we were, by the scale and pervasiveness of these environmental risks. They are present in and around every site where electronic and electric devices are manufactured, used, and thrown away, poisoning humans, animals, vegetation, soil, air and water. We are using the term “media” as a portmanteau word to cover a multitude of cultural and communications machines and processes—print, film, radio, television, information and communications technologies (ICT), and consumer electronics (CE). This is not only for analytical convenience, but because there is increasing overlap between the sectors. CE connect to ICT and vice versa; televisions resemble computers; books are read on telephones; newspapers are written through clouds; and so on. Cultural forms and gadgets that were once separate are now linked. The currently fashionable notion of convergence doesn’t quite capture the vastness of this integration, which includes any object with a circuit board, scores of accessories that plug into it, and a global nexus of labor and environmental inputs and effects that produce and flow from it. In 2007, a combination of ICT/CE and media production accounted for between 2 and 3 percent of all greenhouse gases emitted around the world (“Gartner Estimates,”; International Telecommunication Union; Malmodin et al.). Between twenty and fifty million tonnes of electronic waste (e-waste) are generated annually, much of it via discarded cell phones and computers, which affluent populations throw out regularly in order to buy replacements. (Presumably this fits the narcissism of small differences that distinguishes them from their own past.) E-waste is historically produced in the Global North—Australasia, Western Europe, Japan, and the US—and dumped in the Global South—Latin America, Africa, Eastern Europe, Southern and Southeast Asia, and China. It takes the form of a thousand different, often deadly, materials for each electrical and electronic gadget. This trend is changing as India and China generate their own media detritus (Robinson; Herat). Enclosed hard drives, backlit screens, cathode ray tubes, wiring, capacitors, and heavy metals pose few risks while these materials remain encased. But once discarded and dismantled, ICT/CE have the potential to expose workers and ecosystems to a morass of toxic components. Theoretically, “outmoded” parts could be reused or swapped for newer parts to refurbish devices. But items that are defined as waste undergo further destruction in order to collect remaining parts and valuable metals, such as gold, silver, copper, and rare-earth elements. This process causes serious health risks to bones, brains, stomachs, lungs, and other vital organs, in addition to birth defects and disrupted biological development in children. Medical catastrophes can result from lead, cadmium, mercury, other heavy metals, poisonous fumes emitted in search of precious metals, and such carcinogenic compounds as polychlorinated biphenyls, dioxin, polyvinyl chloride, and flame retardants (Maxwell and Miller 13). The United States’ Environmental Protection Agency estimates that by 2007 US residents owned approximately three billion electronic devices, with an annual turnover rate of 400 million units, and well over half such purchases made by women. Overall CE ownership varied with age—adults under 45 typically boasted four gadgets; those over 65 made do with one. The Consumer Electronics Association (CEA) says US$145 billion was expended in the sector in 2006 in the US alone, up 13% on the previous year. The CEA refers joyously to a “consumer love affair with technology continuing at a healthy clip.” In the midst of a recession, 2009 saw $165 billion in sales, and households owned between fifteen and twenty-four gadgets on average. By 2010, US$233 billion was spent on electronic products, three-quarters of the population owned a computer, nearly half of all US adults owned an MP3 player, and 85% had a cell phone. By all measures, the amount of ICT/CE on the planet is staggering. As investigative science journalist, Elizabeth Grossman put it: “no industry pushes products into the global market on the scale that high-tech electronics does” (Maxwell and Miller 2). In 2007, “of the 2.25 million tons of TVs, cell phones and computer products ready for end-of-life management, 18% (414,000 tons) was collected for recycling and 82% (1.84 million tons) was disposed of, primarily in landfill” (Environmental Protection Agency 1). Twenty million computers fell obsolete across the US in 1998, and the rate was 130,000 a day by 2005. It has been estimated that the five hundred million personal computers discarded in the US between 1997 and 2007 contained 6.32 billion pounds of plastics, 1.58 billion pounds of lead, three million pounds of cadmium, 1.9 million pounds of chromium, and 632000 pounds of mercury (Environmental Protection Agency; Basel Action Network and Silicon Valley Toxics Coalition 6). The European Union is expected to generate upwards of twelve million tons annually by 2020 (Commission of the European Communities 17). While refrigerators and dangerous refrigerants account for the bulk of EU e-waste, about 44% of the most toxic e-waste measured in 2005 came from medium-to-small ICT/CE: computer monitors, TVs, printers, ink cartridges, telecommunications equipment, toys, tools, and anything with a circuit board (Commission of the European Communities 31-34). Understanding the enormity of the environmental problems caused by making, using, and disposing of media technologies should arrest our enthusiasm for them. But intellectual correctives to the “love affair” with technology, or technophilia, have come and gone without establishing much of a foothold against the breathtaking flood of gadgets and the propaganda that proclaims their awe-inspiring capabilities.[i] There is a peculiar enchantment with the seeming magic of wireless communication, touch-screen phones and tablets, flat-screen high-definition televisions, 3-D IMAX cinema, mobile computing, and so on—a totemic, quasi-sacred power that the historian of technology David Nye has named the technological sublime (Nye Technological Sublime 297).[ii] We demonstrate in our book why there is no place for the technological sublime in projects to green the media. But first we should explain why such symbolic power does not accrue to more mundane technologies; after all, for the time-strapped cook, a pressure cooker does truly magical things. Three important qualities endow ICT/CE with unique symbolic potency—virtuality, volume, and novelty. The technological sublime of media technology is reinforced by the “virtual nature of much of the industry’s content,” which “tends to obscure their responsibility for a vast proliferation of hardware, all with high levels of built-in obsolescence and decreasing levels of efficiency” (Boyce and Lewis 5). Planned obsolescence entered the lexicon as a new “ethics” for electrical engineering in the 1920s and ’30s, when marketers, eager to “habituate people to buying new products,” called for designs to become quickly obsolete “in efficiency, economy, style, or taste” (Grossman 7-8).[iii] This defines the short lifespan deliberately constructed for computer systems (drives, interfaces, operating systems, batteries, etc.) by making tiny improvements incompatible with existing hardware (Science and Technology Council of the American Academy of Motion Picture Arts and Sciences 33-50; Boyce and Lewis). With planned obsolescence leading to “dizzying new heights” of product replacement (Rogers 202), there is an overstated sense of the novelty and preeminence of “new” media—a “cult of the present” is particularly dazzled by the spread of electronic gadgets through globalization (Mattelart and Constantinou 22). References to the symbolic power of media technology can be found in hymnals across the internet and the halls of academe: technologies change us, the media will solve social problems or create new ones, ICTs transform work, monopoly ownership no longer matters, journalism is dead, social networking enables social revolution, and the media deliver a cleaner, post-industrial, capitalism. Here is a typical example from the twilight zone of the technological sublime (actually, the OECD): A major feature of the knowledge-based economy is the impact that ICTs have had on industrial structure, with a rapid growth of services and a relative decline of manufacturing. Services are typically less energy intensive and less polluting, so among those countries with a high and increasing share of services, we often see a declining energy intensity of production … with the emergence of the Knowledge Economy ending the old linear relationship between output and energy use (i.e. partially de-coupling growth and energy use) (Houghton 1) This statement mixes half-truths and nonsense. In reality, old-time, toxic manufacturing has moved to the Global South, where it is ascendant; pollution levels are rising worldwide; and energy consumption is accelerating in residential and institutional sectors, due almost entirely to ICT/CE usage, despite advances in energy conservation technology (a neat instance of the age-old Jevons Paradox). In our book we show how these are all outcomes of growth in ICT/CE, the foundation of the so-called knowledge-based economy. ICT/CE are misleadingly presented as having little or no material ecological impact. In the realm of everyday life, the sublime experience of electronic machinery conceals the physical work and material resources that go into them, while the technological sublime makes the idea that more-is-better palatable, axiomatic; even sexy. In this sense, the technological sublime relates to what Marx called “the Fetishism which attaches itself to the products of labour” once they are in the hands of the consumer, who lusts after them as if they were “independent beings” (77). There is a direct but unseen relationship between technology’s symbolic power and the scale of its environmental impact, which the economist Juliet Schor refers to as a “materiality paradox” —the greater the frenzy to buy goods for their transcendent or nonmaterial cultural meaning, the greater the use of material resources (40-41). We wrote Greening the Media knowing that a study of the media’s effect on the environment must work especially hard to break the enchantment that inflames popular and elite passions for media technologies. We understand that the mere mention of the political-economic arrangements that make shiny gadgets possible, or the environmental consequences of their appearance and disappearance, is bad medicine. It’s an unwelcome buzz kill—not a cool way to converse about cool stuff. But we didn’t write the book expecting to win many allies among high-tech enthusiasts and ICT/CE industry leaders. We do not dispute the importance of information and communication media in our lives and modern social systems. We are media people by profession and personal choice, and deeply immersed in the study and use of emerging media technologies. But we think it’s time for a balanced assessment with less hype and more practical understanding of the relationship of media technologies to the biosphere they inhabit. Media consumers, designers, producers, activists, researchers, and policy makers must find new and effective ways to move ICT/CE production and consumption toward ecologically sound practices. In the course of this project, we found in casual conversation, lecture halls, classroom discussions, and correspondence, consistent and increasing concern with the environmental impact of media technology, especially the deleterious effects of e-waste toxins on workers, air, water, and soil. We have learned that the grip of the technological sublime is not ironclad. Its instability provides a point of departure for investigating and criticizing the relationship between the media and the environment. The media are, and have been for a long time, intimate environmental participants. Media technologies are yesterday’s, today’s, and tomorrow’s news, but rarely in the way they should be. The prevailing myth is that the printing press, telegraph, phonograph, photograph, cinema, telephone, wireless radio, television, and internet changed the world without changing the Earth. In reality, each technology has emerged by despoiling ecosystems and exposing workers to harmful environments, a truth obscured by symbolic power and the power of moguls to set the terms by which such technologies are designed and deployed. Those who benefit from ideas of growth, progress, and convergence, who profit from high-tech innovation, monopoly, and state collusion—the military-industrial-entertainment-academic complex and multinational commandants of labor—have for too long ripped off the Earth and workers. As the current celebration of media technology inevitably winds down, perhaps it will become easier to comprehend that digital wonders come at the expense of employees and ecosystems. This will return us to Max Weber’s insistence that we understand technology in a mundane way as a “mode of processing material goods” (27). Further to understanding that ordinariness, we can turn to the pioneering conversation analyst Harvey Sacks, who noted three decades ago “the failures of technocratic dreams [:] that if only we introduced some fantastic new communication machine the world will be transformed.” Such fantasies derived from the very banality of these introductions—that every time they took place, one more “technical apparatus” was simply “being made at home with the rest of our world’ (548). Media studies can join in this repetitive banality. Or it can withdraw the welcome mat for media technologies that despoil the Earth and wreck the lives of those who make them. In our view, it’s time to green the media by greening media studies. References “A Cyber-House Divided.” Economist 4 Sep. 2010: 61-62. “Gartner Estimates ICT Industry Accounts for 2 Percent of Global CO2 Emissions.” Gartner press release. 6 April 2007. ‹http://www.gartner.com/it/page.jsp?id=503867›. Basel Action Network and Silicon Valley Toxics Coalition. Exporting Harm: The High-Tech Trashing of Asia. Seattle: Basel Action Network, 25 Feb. 2002. Benjamin, Walter. “Central Park.” Trans. Lloyd Spencer with Mark Harrington. New German Critique 34 (1985): 32-58. Biagioli, Mario. “Postdisciplinary Liaisons: Science Studies and the Humanities.” Critical Inquiry 35.4 (2009): 816-33. Boyce, Tammy and Justin Lewis, eds. Climate Change and the Media. New York: Peter Lang, 2009. Commission of the European Communities. “Impact Assessment.” Commission Staff Working Paper accompanying the Proposal for a Directive of the European Parliament and of the Council on Waste Electrical and Electronic Equipment (WEEE) (recast). COM (2008) 810 Final. Brussels: Commission of the European Communities, 3 Dec. 2008. Environmental Protection Agency. Management of Electronic Waste in the United States. Washington, DC: EPA, 2007 Environmental Protection Agency. Statistics on the Management of Used and End-of-Life Electronics. Washington, DC: EPA, 2008 Grossman, Elizabeth. Tackling High-Tech Trash: The E-Waste Explosion & What We Can Do about It. New York: Demos, 2008. ‹http://www.demos.org/pubs/e-waste_FINAL.pdf› Herat, Sunil. “Review: Sustainable Management of Electronic Waste (e-Waste).” Clean 35.4 (2007): 305-10. Houghton, J. “ICT and the Environment in Developing Countries: Opportunities and Developments.” Paper prepared for the Organization for Economic Cooperation and Development, 2009. International Telecommunication Union. ICTs for Environment: Guidelines for Developing Countries, with a Focus on Climate Change. Geneva: ICT Applications and Cybersecurity Division Policies and Strategies Department ITU Telecommunication Development Sector, 2008. Malmodin, Jens, Åsa Moberg, Dag Lundén, Göran Finnveden, and Nina Lövehagen. “Greenhouse Gas Emissions and Operational Electricity Use in the ICT and Entertainment & Media Sectors.” Journal of Industrial Ecology 14.5 (2010): 770-90. Marx, Karl. Capital: Vol. 1: A Critical Analysis of Capitalist Production, 3rd ed. Trans. Samuel Moore and Edward Aveling, Ed. Frederick Engels. New York: International Publishers, 1987. Mattelart, Armand and Costas M. Constantinou. “Communications/Excommunications: An Interview with Armand Mattelart.” Trans. Amandine Bled, Jacques Guot, and Costas Constantinou. Review of International Studies 34.1 (2008): 21-42. Mattelart, Armand. “Cómo nació el mito de Internet.” Trans. Yanina Guthman. El mito internet. Ed. Victor Hugo de la Fuente. Santiago: Editorial aún creemos en los sueños, 2002. 25-32. Maxwell, Richard and Toby Miller. Greening the Media. New York: Oxford University Press, 2012. Nye, David E. American Technological Sublime. Cambridge, Mass.: MIT Press, 1994. Nye, David E. Technology Matters: Questions to Live With. Cambridge, Mass.: MIT Press. 2007. Orwell, George. “As I Please.” Tribune. 12 May 1944. Richtel, Matt. “Consumers Hold on to Products Longer.” New York Times: B1, 26 Feb. 2011. Robinson, Brett H. “E-Waste: An Assessment of Global Production and Environmental Impacts.” Science of the Total Environment 408.2 (2009): 183-91. Rogers, Heather. Gone Tomorrow: The Hidden Life of Garbage. New York: New Press, 2005. Sacks, Harvey. Lectures on Conversation. Vols. I and II. Ed. Gail Jefferson. Malden: Blackwell, 1995. Schiller, Herbert I. Information and the Crisis Economy. Norwood: Ablex Publishing, 1984. Schor, Juliet B. Plenitude: The New Economics of True Wealth. New York: Penguin, 2010. Science and Technology Council of the American Academy of Motion Picture Arts and Sciences. The Digital Dilemma: Strategic Issues in Archiving and Accessing Digital Motion Picture Materials. Los Angeles: Academy Imprints, 2007. Weber, Max. “Remarks on Technology and Culture.” Trans. Beatrix Zumsteg and Thomas M. Kemple. Ed. Thomas M. Kemple. Theory, Culture [i] The global recession that began in 2007 has been the main reason for some declines in Global North energy consumption, slower turnover in gadget upgrades, and longer periods of consumer maintenance of electronic goods (Richtel). [ii] The emergence of the technological sublime has been attributed to the Western triumphs in the post-Second World War period, when technological power supposedly supplanted the power of nature to inspire fear and astonishment (Nye Technology Matters 28). Historian Mario Biagioli explains how the sublime permeates everyday life through technoscience: "If around 1950 the popular imaginary placed science close to the military and away from the home, today’s technoscience frames our everyday life at all levels, down to our notion of the self" (818). [iii] This compulsory repetition is seemingly undertaken each time as a novelty, governed by what German cultural critic Walter Benjamin called, in his awkward but occasionally illuminating prose, "the ever-always-the-same" of "mass-production" cloaked in "a hitherto unheard-of significance" (48).