Surface modification and functionalization of powder materials by atomic layer deposition: a review

Atomic layer deposition is a technique where gaseous precursors are used to form materials via self-limiting surface reactions. This allows conformal deposition materials on a high surface area support at the atomic level, and materials can by precisely constructed.

Multiobjective Bayesian optimization and joint inversion for active sensor fusion

A critical decision process in data acquisition for mineral and energy resource exploration is how to efficiently combine a variety of sensor types and how to minimize the total cost. We have developed a probabilistic framework for multiobjective optimization and inverse problems given an expensive cost function for allocating new measurements. This new method is devised to jointly solve multilinear forward models of 2D sensor data and 3D geophysical properties using sparse Gaussian process kernels while taking into account the cross-variances of different parameters. Multiple optimization strategies are tested and evaluated on a set of synthetic and real geophysical data. We determine the advantages on a specific example of a joint inverse problem, recommending where to place new drill-core measurements given 2D gravity and magnetic sensor data; the same approach can be applied to a variety of remote sensing problems with linear forward models — ranging from constraints limiting surface access for data acquisition to adaptive multisensor positioning.

Scaling Up of Local Ice Pressures for a Fixed Offshore Platform Based on Ice Basin Model Data

Fundamentals of the similarity theory in the ice deformation mechanics, as well as problems related to scaling up of local ice pressures measured during tests in an ice basin to full scale values are considered. A new scaling principle based on a hypothesis of ice deformation limiting surface isomorphism and direct computer simulation is proposed. An ice-resistant platform, for which local pressures were measured in ice tests and ice pressures were recalculated to full scale values using generated ice deformation limiting surfaces, was considered as an example.

Optimal temperature overshoot profile found by limiting global sea level rise as a lower-cost climate target

The global temperature targets of limiting surface warming to below 2.0°C or even to 1.5°C have been widely accepted through the Paris Agreement. However, limiting surface warming has previously been proven insufficient to control sea level rise (SLR). Here, we explore a sea level target that is closer to coastal planning and associated adaptation measures than a temperature target. We find that a sea level target provides an optimal temperature overshoot profile through a physical constraint of SLR. The allowable temperature overshoot leads to lower mitigation costs and more effective long-term sea level stabilization compared to a temperature target leading to the same SLR by 2200. With the same mitigation cost as the temperature target, a SLR target could bring surface warming back to the targeted temperatures within this century, lead to a reduction of surface warming of the next century, and reduce and slow down SLR in the centuries thereafter.

ON THE CALCULATION OF CONVECTIVE HEAT TRANSFER UNDER MUTUAL-ACTION OF A JET WITH LIMITING SURFACE

The paper proposes a method for calculating convective heat transfer in the interaction of a single circular jet with a flat surface. The differences of the proposed method from the existing ones are given. The concepts “energodynamic potential of the flow” and “energodynamic power of the flow” are introduced, allowing to determine the intensity of convective heat transfer at “gas-solid” boundary. Differences of the proposed definitions from the existing ones are given: heat flux and heat flux density. The principal difference between the heat flux density q and the energy dynamic potential qэ is as follows: the heat flux density q for convective heat transfer problems means the amount of heat that is transferred from a liquid to a solid surface (or vice versa) per unit of time through a unit of heat exchange surface area. Thus, quantity q characterizes the intensity of convective heat transfer process at the interface. The energy dynamic potential qэ characterizes the flow property as a source or carrier of heat. Value of qэ characterizes the specific energy power of the fluid flow. When calculating the heat transfer, it was proposed to divide the jet when interacting with the flat surface into two parts: before the interaction – the jet part, after – the fan flow. The method for calculating convective heat transfer under jet heating, in which the Reynolds criterion calculated by characteristics of the gas at the nozzle exit is decisive, is not entirely correct. It is proposed to use criteria specific to the fan flow. Characteristic values for the fan flow are its initial average velocity Uвп, distance from the critical point of the jet (point of intersection of vertical axis of the jet with the surface) to the current coordinate of radius downstream. To assess the changes in basic characteristics of a free jet at different distances from the nozzle exit to limiting surface, dependences of the following criteria are presented: jet expansion coefficient; jet injection coefficient; velocity coefficient for any jet section; velocity coefficient for any jet section, except h/d0 = 0; relation of the Reynolds criteria, confirming the need to carry out calculations of heat transfer on the values characteristic separately for the fan flow.

Dissolving uptake-hindering surface defects in metal–organic frameworks

Performance-limiting surface defects in metal–organic frameworks caused by exposure to a humid environment can be dissolved by exposure to ethanol.