Constraints on the ice composition of carbonaceous chondrites from their magnetic mineralogy

Carbonaceous chondrites experienced varying degrees of aqueous alteration on their parent asteroids, which influenced their mineralogies, textures, and bulk chemical and isotopic compositions. Although this alteration was a crucial event in the history of these meteorites, their various alteration pathways are not well understood. One phase that formed during this alteration was magnetite, and its morphology and abundance vary between and within chondrite groups, providing a means of investigating chondrite aqueous alteration. We measured bulk magnetic properties and first-order reversal curve (FORC) diagrams of CM, CI, CO, and ungrouped C2 chondrites to identify the morphology and size range of magnetite present in these meteorites. We identify two predominant pathways of aqueous alteration among these meteorites that can be distinguished by the resultant morphology of magnetite. In WIS 91600, Tagish Lake, and CI chondrites, magnetite forms predominantly from Fe-sulfides as framboids and stacked plaquettes. In CM and CO chondrites, <0.1 μm single-domain (SD) magnetite and 0.1–5 μm vortex (V) state magnetite formed predominantly via the direct replacement of metal and Fe-sulfides. After ruling out differences in temperature, water:rock ratios, terrestrial weathering effects, and starting mineralogy, we hypothesise that the primary factor controlling the pathway of aqueous alteration was the composition of the ice accreted into each chondrite group’s parent body. Nebula condensation sequences predict that the most feasible method of appreciably evolving ice concentrations was the condensation of ammonia, which will have formed a more alkaline hydrous fluid upon melting, leading to fundamentally different conditions that may have caused the formation of different magnetite morphologies. As such, we suggest that WIS 91600, Tagish Lake, and the CI chondrites accreted past the ammonia ice line, supporting a more distal or younger accretion of their parent asteroids.

Essays: myths and dead ends of artificial intelligence

The article contains an analysis of the philosophical foundations of the very idea of creating and implementing artificial intelligence via comparison by analogy with the hypothetical concept of "artificial life". The logical and conceptual unfoundedness of common definitions of artificial intelligence is demonstrated. The article offers the understanding of intelligence as an exclusively natural way of solving tasks, and not as a common function that can be implemented on the basis of other technologies. The conclusion is made about the inexpediency of direct replacement of a human with devices with artificial intelligence without a fundamental change in the basic principles of organizing field of activity. The questionableness of the idea of creating general artificial intelligence as a universal local device with a unified architecture in the presence of many specialized devices is substantiated. Doubts are expressed about the effectiveness of the application of evolutionary methods and learning procedures in the design of devices that solve tasks that are considered intelligent.

DERIVATIZATION OF SOYBEAN OIL TO ENHANCE PERFORMANCE AS A PROCESSING OIL IN SBR-BASED RUBBER COMPOUNDS

ABSTRACT Although soybean oil (SBO) has been used as a bio-based processing oil (PO) for rubber compounds, direct replacement of a conventional petroleum-based PO with SBO often results in a reduction of some important properties. As a result, it was of interest to investigate two higher molecular weight SBO-derived materials as POs, namely, sucrose octasoyate (SS) and poly(2-vinyloxyethyl)soyate (P2VOES). When these compounds were used in carbon black (CB)-filled SBR, mechanical properties were significantly improved. This result was mainly attributed to higher crosslink densities resulting from their higher degree of unsaturation per molecule as compared with SBO. Higher unsaturation per molecule increases the probability that the PO will be incorporated into the crosslinked network as elastically effective crosslinks as opposed to dangling chain ends. With regard to tire tread performance, both SS and P2VOES-based vulcanizates showed a lower predicted rolling resistance than the SBO-based control, and the P2VOES vulcanizate showed a better balance between rolling resistance and wet traction. Vulcanizates derived from SS and P2VOES showed a small tangent delta peak between −13 and 35 °C that might be associated with relatively highly crosslinked domains rich in SS or P2VOES.

Geography Pre-Service Teachers’ Perspectives on Multimedia Technology and Environmental Education

Multimedia technology (MT) is now widely used in primary and secondary classrooms and has excellent potential for environmental education. The discipline of Geography has strong synergies with environmental education. The paper uses the Q methodology to investigate the responses of pre-service geography teachers regarding the use of multimedia in environmental education (EE). The viewpoints of respondents were clustered into three broad perspectives relating to the use of multimedia: Perspective 1: the use of multimedia is regarded as valuable but difficult to apply; perspective 2: the use of multimedia is rewarding and practicable; perspective 3: the use of all types of multimedia is seen as highly valuable, although in the case of GIS the attitude is more equivocal. All three perspectives align with the idea that MT can improve EE, although the respondents suggest it cannot be a direct replacement for fieldwork. While all three perspectives are consistent with the view that multimedia teaching has many functional advantages in relation to environmental education, concerns are expressed regarding teachers’ capacity to fulfill its potential. The authors suggest that understanding these perspectives can help improve pre-service teacher education and advance environment education in middle school.

A Comparison of Partial Discharge Sensors for Natural Gas Insulated High Voltage Equipment

The research in this paper consists of practical experimentation on a gas insulated section of high voltage equipment filled with carbon dioxide and technical air as a direct replacement to sulphur hexafluoride (SF6) and analyses the results of PD measurement by way of internal UHF sensors and external HFCTs. The results contribute to ongoing efforts to replace the global warming gas SF6 with an alternative such as pure carbon dioxide or technical air and are applicable to mixtures of electronegative gases that have a high content of buffer gas including carbon dioxide. The experiments undertaken involved filling a full-scale gas insulated line demonstrator with different pressures of CO2 or technical air and applying voltages up to 242 kV in both clean conditions and particle contaminated conditions. The results show that carbon dioxide and technical air can insulate a gas section normally insulated with SF6 at phase-to-earth voltage of 242 kV and that both HFCT and UHF sensors can be used to detect partial discharge with natural gases. The internal UHF sensors show the most accurate PD location results but external HFCTs offer a good compromise and very similar location accuracy.

Mathematical Description of Elastic Phenomena which Uses Caputo or Riemann-Liouville Fractional Order Partial Derivatives is Nonobjective

In this paper it is shown that mathematical description of strain, constitutive law and dynamics obtained by direct replacement of integer order derivatives with Caputo or Riemann-Liouville fractional order partial derivatives, having integral representation on finite interval, in case of a guitar string, is nonobjective. The basic idea is that different observers, using this type of descriptions, obtain different results which cannot be reconciled, i.e. transformed into each other using only formulas that link the coordinates of the same point in two fixed orthogonal reference frames and formulas that link the numbers representing the same moment of time in two different choices of the origin of time measuring. This is not an academic curiosity! It is rather a problem: which one of the obtained results is correct?

LdsConv: Learned Depthwise Separable Convolutions by Group Pruning

Standard convolutional filters usually capture unnecessary overlap of features resulting in a waste of computational cost. In this paper, we aim to solve this problem by proposing a novel Learned Depthwise Separable Convolution (LdsConv) operation that is smart but has a strong capacity for learning. It integrates the pruning technique into the design of convolutional filters, formulated as a generic convolutional unit that can be used as a direct replacement of convolutions without any adjustments of the architecture. To show the effectiveness of the proposed method, experiments are carried out using the state-of-the-art convolutional neural networks (CNNs), including ResNet, DenseNet, SE-ResNet and MobileNet, respectively. The results show that by simply replacing the original convolution with LdsConv in these CNNs, it can achieve a significantly improved accuracy while reducing computational cost. For the case of ResNet50, the FLOPs can be reduced by 40.9%, meanwhile the accuracy on the associated ImageNet increases.

PROBLEMS AND PROSPECTS OF LED LAMP RETROPHYTES

The article discusses modern light sources – LED retrofit lamps, which are used to replace traditional light sources (incandescent, fluorescent lamps). The article provides calculated data showing energy savings as a result of replacing traditional light sources with LED ones. LEDs have undeniable advantages over such light sources. This is a high luminous efficiency, durability, color reproduction and much more. Ample opportunities for direct replacement of LED lamps are associated with their form factor, which is the same as that of traditional light sources. The main parameters of the form factor in this case are the sizes of the light sources (bulb diameter) and the type of cap. However, direct replacement has many controversial sides. Firstly, the light environment created by traditional incandescent lamps is very different from that for LED light sources due to the difference in their spectral light distribution. Secondly, the light intensity curves of LED and traditional light sources are very different in a number of cases. Therefore, direct replacement must be carried out very carefully, taking into account the final light distribution of the light device, where they are used. Thirdly, due to the incompleteness of research in the field of safety of LED lighting, the use of such light sources can be limited due to the potential hazard that may lead to a decrease in labor productivity and quality of life. Fourth, the design of LED lamps is complex, their quality depends on the quality of LEDs, phosphors and electronics, so consumer properties may not be at the highest level, even at fairly high prices. Fifthly, for any, even the simplest LED lamp, a heat sink system is necessary, since the thermal regime of the lamps imposes certain restrictions on their use.

Fatigue Performance of the Novel Titanium Alloy TIMETAL®407

TIMETAL®407 (Ti-407) is a novel titanium alloy formulated as a medium strength, highly ductile alloy offering a range of manufacturing cost reduction opportunities. It can be used as a direct replacement for Ti-6Al-4V or Ti-3Al-2.5V alloys, particularly in applications where energy absorption during fracture or HCF endurance are the key design criteria. The effect of thermo-mechanical processing on microstructure has been characterised and the room temperature high cycle, low cycle and dwell cycle fatigue properties of Ti-407 containing 30-40% primary alpha volume fraction are presented and discussed. These results are compared with data generated from Ti-6Al-4V processed to provide a similar but non-standard microstructure and demonstrate that Ti-407 shows superior HCF endurance strength, despite having a significantly lower tensile and yield strength.

Pragmatic differentiation of negative markers in the early stages of Jespersen’s cycle in North Germanic

This article investigates the pragmatic function of new negative markers during incipient renewal of negation in ‘Jespersen’s cycle’. We outline a typology of these markers, suggesting a pathway by which they begin as specialized for use with discourse-old propositions and later expand to inferred propositions before finally becoming possible with discourse-new propositions. This framework is applied to an overlooked case of Jespersen’s cycle in North Germanic: replacement of early Norwegian ei(gi) “not” by ekki (originally “nothing”) from 1250 to 1550. We document a sharp rise in frequency of ekki around 1425, suggesting that, until then, ekki had been restricted to negating discourse-old propositions. Once this constraint was lifted, ei(gi) and ekki competed directly, resulting in rapid replacement of ei(gi) by ekki. This typologically unusual direct replacement of a negator with no intervening doubling stage can be attributed to the new negator’s origin as a negative indefinite and the lack of negative concord in early Norwegian.