We present cosmological parameter measurements from the Deep Lens Survey (DLS) using galaxy-mass and galaxy-galaxy power spectra in the multipole range = 250-2000. We measure galaxy-galaxy power ...spectra from two lens bins centered at z ∼ 0.27 and 0.54 and galaxy-mass power spectra by cross-correlating the positions of galaxies in these two lens bins with galaxy shapes in two source bins centered at z ∼ 0.64 and 1.1. We marginalize over a baryonic feedback process using a single-parameter representation and a sum of neutrino masses, as well as photometric redshift and shear calibration systematic uncertainties. For a flat ΛCDM cosmology, we determine , in good agreement with our previous DLS cosmic shear and the Planck cosmic microwave background (CMB) measurements. Without the baryonic feedback marginalization, S8 decreases by because the dark-matter-only power spectrum lacks the suppression at the highest values owing to active galactic nucleus (AGN) feedback. Together with the Planck CMB measurements, we constrain the baryonic feedback parameter to , which suggests an interesting possibility that the actual AGN feedback might be stronger than the recipe used in the OverWhelmingly Large cosmological hydrodynamical Simulations. The interpretation is limited by the validity of the baryonic feedback simulation and the one-parameter representation of the effect.
The morphology and substructure of α′ martensite in Ti-6Al-4V cuboid samples produced by selective laser melting (SLM) have been investigated to explore the formation mechanism and control method of ...α′ martensite. Results showed that the microstructures of SLMed Ti-6Al-4V samples are composed of a typical hierarchical martensite structure with a high density of dislocations and twins, including primary, secondary, tertiary and quartic α′ martensites within columnar prior β grains. Also, the formation and evolution mechanisms of such hierarchical martensites are proposed based on heat history of SLM, material characteristics and substructure features. Besides, based on quantitative metallography, the lengths of major and minor axes as well as aspect ratio of primary and secondary α′ martensites are mainly in the range of 10–70μm, 1.0–2.0μm and 5–40, respectively. The martensitic sizes increase with hatch spacing, but firstly increase and then decrease with the increase of scanning velocity from 600 to 1100mm/s. So, martensitic size can be controlled by adjusting the SLM processing parameters.
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•A hierarchical α′ structure is observed in selective laser melted Ti-6Al-4V.•Martensitic size of selective laser melted Ti-6Al-4V is measured.•Formation mechanism of α′ during multiple thermal cycles is proposed.•Varying parameters of selective laser melting can control martensitic size.
Additive manufacturing technologies based on melting and solidification have considerable similarities with fusion-based welding technologies, either by electric arc or high-power beams. However, ...several concepts are being introduced in additive manufacturing which have been extensively used in multipass arc welding with filler material. Therefore, clarification of fundamental definitions is important to establish a common background between welding and additive manufacturing research communities. This paper aims to review these concepts, highlighting the distinctive characteristics of fusion welding that can be embraced by additive manufacturing, namely the nature of rapid thermal cycles associated to small size and localized heat sources, the non-equilibrium nature of rapid solidification and its effects on: internal defects formation, phase transformations, residual stresses and distortions. Concerning process optimization, distinct criteria are proposed based on geometric, energetic and thermal considerations, allowing to determine an upper bound limit for the optimum hatch distance during additive manufacturing. Finally, a unified equation to compute the energy density is proposed. This equation enables to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.
This study presents the correlation between process parameters and porosity formation in a TiAl6V4 alloy produced by selective laser melting. The porosity is investigated by 2D and 3D methods aiming ...to identify the mechanisms of void formation, their morphology as well as volume fraction as a function of the energy density. An evident minimum volume fraction is observed between process parameters with significant overheating and insufficient fusion. It is shown that these two marginal regions define two mechanisms of void formation. Two dominant types of voids morphology are identified and examined regarding pore orientation versus their elongation, which together with the curvature distribution analysis allow revealing critical defects.
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•The initial porosity of SLM Ti6Al4V was significantly reduced by applying a systematic processing strategy.•Marginal applied energy densities - excessive or insufficient - lead to two different mechanisms of pore formation.•The correlation between pore orientation, and morphology allowed revealing voids critical for mechanical performance.•Process optimization should consider pore formation mechanisms besides overall porosity to achieve low-void microstructures.
One of the main objectives of technical diagnostics is identification the technical state of the machine. The technical state is described by the values of the object cardinal features. ...Unfortunately, during the operation process, some of the values of these features cannot be measured. It is proposed to estimate the values of the cardinal features based on their initial values and the influence of the forcing factors described by the time histories of the parameters of the operation process. Due to the limited knowledge of the correlation between operational parameters and forcing factors it was modelled in form of fuzzy Mamdani models. In the paper universal automatic method of the models generation was presented. Thanks to it, it was possible to generate the model of the technical state changes in automatic manner. The results of the usage of the generated model in case of real complex technical system can be found at the end of the paper.
Water and adhesives have a conflicting relationship as demonstrated by the failure of most man-made adhesives in underwater environments. However, living creatures routinely adhere to substrates ...underwater. For example, sandcastle worms create protective reefs underwater by secreting a cocktail of protein glue that binds mineral particles together, and mussels attach themselves to rocks near tide-swept sea shores using byssal threads formed from their extracellular secretions. Over the past few decades, the physicochemical examination of biological underwater adhesives has begun to decipher the mysteries behind underwater adhesion. These naturally occurring adhesives have inspired the creation of several synthetic materials that can stick underwater - a task that was once thought to be "impossible". This review provides a comprehensive overview of the progress in the science of underwater adhesion over the past few decades. In this review, we introduce the basic thermodynamics processes and kinetic parameters involved in adhesion. Second, we describe the challenges brought by water when adhering underwater. Third, we explore the adhesive mechanisms showcased by mussels and sandcastle worms to overcome the challenges brought by water. We then present a detailed review of synthetic underwater adhesives that have been reported to date. Finally, we discuss some potential applications of underwater adhesives and the current challenges in the field by using a tandem analysis of the reported chemical structures and their adhesive strength. This review is aimed to inspire and facilitate the design of novel synthetic underwater adhesives, that will, in turn expand our understanding of the physical and chemical parameters that influence underwater adhesion.
Water prevents adhesion by disrupting the interfacial interactions and weakening the cohesive network of the adhesive. This review summarizes the recent developments in the physical and chemical design principles of underwater adhesives.
Water industries worldwide consider coagulation/flocculation to be one of the major treatment methods for improving the overall efficiency and cost effectiveness of water and wastewater treatment. ...Enhancing the coagulation process is currently a popular research topic. In this review article, the latest developments in enhanced coagulation are summarized. In addition, the mechanisms of enhanced coagulation and the effect of process parameters on processing efficiency are discussed from the perspective of ballast-enhanced coagulation, preoxidation, ultrasound, and composite coagulants. Finally, improvements and new directions for enhanced coagulation are proposed.
This review summarizes the current situation of enhanced coagulation and looks forward to future development.
•Review the existing knowledge on the biochar properties and its future perspectives;•Biochar is derived from waste biomass using pyrolysis techniques reviewed;•Different modification technologies ...were extensively mentioned in this review;•Modified biochar had a better function in application compared with original biochar;•TEA and LCA of biochar have been reviewed in depth and discussed.
Biochar generation from biomass pyrolysis is an appealing and practical technology for storing carbon and lowering the greenhouse gas (GHG) emissions. Carbon recalcitrance in biochar, also known as biochar stability, is an important feature that determines carbon sequestration capacity. Further, the stability of biochar affects the varying process parameter, which flatters the frontier of biochar study. Also, the properties of biochar substantially alter with the various parameters such as operating constraints, types of feedstock, reactors types, etc. In this review, the stability of biochar is explored in-depth, as well as how and why biomass handling variables such as pyrolysis temperature and reaction residence time, compositions and physicochemical properties impact on it. Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA) of biochar are also highlighted in this review. This review invalidates the failure of current research to give weight to such important concerns in the exposure of TEA and LCA to biochar production. According to this review, relatively high temperatures (400–900 °C), extended residence and holding times, moderate heating rates, certain minerals, and biomass feedstock with a high lignin content and big particle size are desirable for biochar stability. However, the trade-offs between biochar stability and other potential improvements are mediated by constraints. The compromises between the stability of biochar and other possible gains are mediated by obstacles. In addition to carbon nanotubes, capacitors, energy storage devices, and bio-adsorbents, strategies have been developed to promote the use of biochar as a tool to mitigate climate change. The goal of this review is to improve and commercialize biochar technology to fulfill the needs of many industries; it help to the researcher particularly interested in the thermochemical alteration of feeds and the creation of novel pyrolyzer.
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