The formation of araneiforms by carbon dioxide venting and vigorous sublimation dynamics under martian atmospheric pressure

The local redistribution of granular material by sublimation of the southern seasonal $${\hbox {CO}}_2$$ CO 2 ice deposit is one of the most active surface shaping processes on Mars today. This unique geomorphic mechanism is hypothesised to be the cause of the dendritic, branching, spider-like araneiform terrain and associated fans and spots—features which are native to Mars and have no Earth analogues. However, there is a paucity of empirical data to test the validity of this hypothesis. Additionally, it is unclear whether some araneiform patterns began as radial and then grew outward, or whether troughs connected at mutual centres over time. Here we present the results of a suite of laboratory experiments undertaken to investigate if the interaction between a sublimating $${\hbox {CO}}_2$$ CO 2 ice overburden containing central vents and a porous, mobile regolith will mobilise grains from beneath the ice in the form of a plume to generate araneiform patterns. We quantify the branching and area of the dendritic features that form. We provide the first observations of plume activity via $${\hbox {CO}}_2$$ CO 2 sublimation and consequent erosion to form araneiform features. We show that $${\hbox {CO}}_2$$ CO 2 sublimation can be a highly efficient agent of sediment transport under present day Martian atmospheric pressure and that morphometry is governed by the Shields parameter.

A Preliminary Assessment of Low-Cost Bridge Scour Monitoring Methods and Tools

<p>Scour is a major cause of bridge collapse worldwide.</p><p>Climate change has resulted in flood events increasing both in frequency and in magnitude. Climate change, together with the current uncertainty about maximum scour depth around structures, make scour and other hydraulic actions some of the most important challenges for engineering going forward.</p><p>This study offers a preliminary assessment of bridge scour monitoring methods considering scour as a dynamical earth surface shaping process, and discusses how these methods can be used to improve predictive models for bridge scour depth.</p><p>Current methods used to monitor scour are mostly reactive. A vast amount of research has been carried out, aiming towards the implementation of various approaches to assist in the monitoring of scour; however, most methods used are either still reactive, or extremely costly and therefore not practical to be used for small to medium scale structures. This study aims in addressing major challenges faced by establishing a new, innovative framework for the monitoring of scour, while considering relevant approaches in literature. It discusses the development of an innovative, sustainable and low-cost framework, that can be used for small to medium scale structures. This will ensure a proactive response in the event of catastrophic scour occurring, safeguarding infrastructure and the travelling public.</p>

Investigation of the Influence of the Space Orientation of Layers on the Surface Shape Error during Additive Shaping of Products by an Electric Arc in a Protective Gases Environment

The paper presents the results of a study of the process of additive surface shaping by an electric arc in a protective gas. An analysis was made of the errors in the shape of surfaces obtained with different filling of layers. It has been experimentally confirmed that such process parameters as the orientation of the layers, the coefficient of their overlap are significant and affect the numerical value of the error in the shape of the resulting surface. In this connection, they should be taken into account when designing algorithms for dividing into layers and filling them with additive shaping by an electric arc in a protective gas.

Researches and Simulation of Elastic Recovery Phenomena during Roller Burnishing Process of Macro-Asperities of Surface

The paper presents preliminary studies of a new innovative surface treatment method—the process of roller burnishing of macro-irregularities of the surface. As part of the work, the possibility of plastic shaping of the surface macrostructure with indentations (plateau structure), which will show anti-wear properties through appropriate surface shaping and the compressive stress state in the product’s top layer, was investigated. The essence of the paper is the analysis of one of the aspects of the application of this processing method, i.e., the influence of the elastic recovery of the product on its technological quality measured by dimensional deviation. The main objective of the work is to develop adequate methods and mathematical models to enable the design of the macro-asperities of the surface burnishing process to maintain the dimensional tolerance of the shaped parts. The results of dependencies of elastic recovery of the asperities and the deviation of height, Δht, for sample depths of burnishing were presented. The model tests of the elastic recovery of the model material using the visioplasticity method show that with the increase of the value of the vertical surface asperities, the value of the elastic recovery of the material decreases. The increase of the deviation of the asperities’ height causes a decrease in the value of elastic recovery. With the increase of the value of the vertical angle of the surface roughness, the value of the elastic recovery of the material is smaller.

Классификация методов формообразования и синтез на ее основе схем обработки профильных моментопередающих поверхностей

The paper presents characteristics of the known classifications of surface shaping methods in mechanical engineering during mechanical and physical-technical processing; according to the classifications a surface shaping method is considered as a combination of methods for generating its producing lines – generatrix and guide – provided that the generation rate of the generatrix is higher than the guide. The advantages of constructing a classification and a formalized description of surface shaping methods have been shown in the paper; each of them represents a combination of surface formation methods in cross section and in length, regardless of generation speed for generatrix and guide lines. This increases information content of the description for a shaping method which is important for comparing methods of shaping surfaces and synthesis of schemes for their processing in the functional design of the machine. The paper has revealed the fact that in comparison with the well-known classification of A. A. Fedotenka it is an expedient to introduce methods of bending, intermittent track and intermittent rolling, as well as combined methods combining advantages of their basic methods which expand the synthesis of progressive processing schemes for profile surfaces. The introduction of the methods has been made in many basic methods of generating production lines (copying, following, touching and rolling). Based on the expanded set of basic methods and the accepted principle of presenting the methods of shaping profile surfaces, their classification has been developed as the basis for systematization and synthesis of known and possible shaping methods. The paper considers examples of rational shaping method synthesis based on the proposed classification and progressive processing schemes for profile moment-transmitting surfaces on the basis of synthesis examples. In particular, the use of an envelope method instead of the applied rolling method has made it possible to simplify significantly a tool design, to increase its versatility and accuracy in formation of moment-transmitting surfaces with a profile in the form of a Relo triangle.

Energy Storage Power and Energy Sizing and Specification Using HSSPFC

The intermittent nature of renewable sources requires the integration of Energy Storage Systems (ESSs) with appropriate power and energy densities. One of the applications of Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) is to size ESSs for power and energy densities by employing them as sole actuators of Microgrid (MG) systems. This Article provides a comprehensive yet simplified example of utilization of HSSPFC to size ESSs of inverter-based three-phase MG systems under hierarchical control. Here, the distributed Hamiltonian controller is expanded for control of parallel ESSs and power sharing metrics are defined to distribute power between hybrid storage systems according to their power and energy density capabilities. Simulated hybrid ESSs comprising battery and flywheel systems are used as examples to demonstrate the behaviour of the expanded control, verify the power sharing criteria and illustrate ESS design and specification by utilizing HSSPFC.

“The Skin of the Earth – Where Life meets Rocks” – A Science Movie

<p>What forms the landscapes of the Earth with their mountains, rivers, soils - the places we live in? Earth’s surface is shaped when rocks are uplifted by geologic forces, and are then destroyed by rain, ice, and wind that carve landscapes by erosion and weathering. But there is the green layer of life between rocks below and climate above. Do plants with their roots, animals that dig into soil, and the vast number of microorganisms shape the landscapes? Or do minerals, soil, and water provide the environment for life? Or are they both interdependent? Can they together resist the massive climate change imposed by humans today?</p><p>Showcasing these complex interactions in an audiovisual format provides a fantastic opportunity for science dissemination, but making a movie is a formidable challenge that scientists are not experienced in. Based on the the German National Science Foundation (DFG)- funded research network “EarthShape – Earth Surface Shaping by Biota”, we produced a movie intended as public outreach for scientists as well as classrooms and a general public audience.</p><p>Watch the scientists of the German-Chilean “EarthShape” project study the shaping of the Earth along a climate gradient in Chile, in the National Parks Pan de Azúcar, La Campana, and Nahuelbuta. Take a tour through fascinating landscapes and see the young scientists study the interactions between geology and biology, from the dry Atacama desert to dense forests, and in their sophisticated home laboratories. See how feedbacks control Earths’ climate. The movie is available online in Youtube, including separate process animations, and as Open-Access MP4 resource.</p><p>Playlist on Youtube: https://go.daf.li/EarthShape; DOI of the English movie version: https://doi.org/10.2312/gfz.3.3.2019.005</p>

Friction and wear behavior of Al–Si alloy cylinder liner prepared by surface shaping treatments

In order to improve the friction and wear behavior of Al–Si alloy cylinder liner, the surfaces of cylinder liner samples were prepared by three kinds of surface shaping treatments (chemical etching shaping, mechanical honing shaping, and laser ablation shaping). All the three kinds of surface shaping treatments can expose the silicon particles on the surface of Al–Si alloy cylinder liner, which prevents the contact aluminum from the counterface (piston ring). The area between the two protruding silicon particles can be stored for enhanced lubrication and reduce friction. These shaping surfaces were different. The edges of the silicon particles are made sharp by the chemical etching shaping treatment. The edges of the silicon particles are round but with burr by the mechanical honing shaping treatment. The edges of silicon particles are round but without burr by the laser ablation shaping treatment. The friction coefficient and weight loss are lowest by the laser ablation shaping in three kinds of surface shaping treatments. There are two reasons. On the one hand, the edges of silicon particles are round but without burr, which reduce the stress concentration. On the other hand, the silicon particles combine well with aluminum, which reduce the probability of falling off.

Broadly Protective Multivalent OspA Vaccine against Lyme Borreliosis, Developed Based on Surface Shaping of the C-Terminal Fragment

ABSTRACT The development of vaccines for prevention of diseases caused by pathogenic species can encounter major obstacles if high sequence diversity is observed between individual strains. Therefore, development might be restricted either to conserved antigens, which are often rare, or to multivalent vaccines, which renders the production more costly and cumbersome. In light of this complexity, we applied a structure-based surface shaping approach for the development of a Lyme borreliosis (LB) vaccine suitable for the United States and Europe. The surface of the C-terminal fragment of outer surface protein A (OspA) was divided into distinct regions, based primarily on binding sites of monoclonal antibodies (MAbs). In order to target the six clinically most relevant OspA serotypes (ST) in a single protein, exposed amino acids of the individual regions were exchanged to corresponding amino acids of a chosen OspA serotype. Six chimeric proteins were constructed, and, based on their immunogenicity, four of these chimeras were tested in mouse challenge models. Significant protection could be demonstrated for all four proteins following challenge with infected ticks (OspA ST1, OspA ST2, and OspA ST4) or with in vitro-grown spirochetes (OspA ST1 and OspA ST5). Two of the chimeric proteins were linked to form a fusion protein, which provided significant protection against in vitro-grown spirochetes (OspA ST1) and infected ticks (OspA ST2). This article presents the proof-of-concept study for a multivalent OspA vaccine targeting a wide range of pathogenic LB Borrelia species with a single recombinant antigen for prevention of Lyme borreliosis.