US financial services will help mainstream cryptos

Significance Yet snowballing interest outpaces crypto's use in any of the three main roles of money: a medium of exchange, unit of account or store of value. Crypto accounts for a sliver of US financial assets and retail sales. It remains overshadowed by its reputation as the currency of cybercriminals. Impacts Safeguards to prevent criminals from exploiting crypto will hinder legitimate crypto innovation. Transaction monitoring and know-your-customer due diligence will become a higher priority for crypto exchanges, reducing anonymity. Crypto's non-correlation with equity and bond price movements, an investor attraction, will lessen with broader use

Controlled self-assembly of chemical gardens enables fabrication of heterogeneous chemobrionic materials

Chemical gardens are an example of a chemobrionic system that typically result in abiotic macro-, micro- and nano- material architectures, with formation driven by complex out-of-equilibrium reaction mechanisms. From a technological perspective, controlling chemobrionic processes may hold great promise for the creation of novel, compositionally diverse and ultimately, useful materials and devices. In this work, we engineer an innovative custom-built liquid exchange unit that enables us to control the formation of tubular chemical garden structures grown from the interface between calcium loaded hydrogel and phosphate solution. We show that systematic displacement of phosphate solution with water (H2O) can halt self-assembly, precisely control tube height and purify structures in situ. Furthermore, we demonstrate the fabrication of a heterogeneous chemobrionic composite material composed of aligned, high-aspect ratio calcium phosphate channels running through an otherwise dense matrix of poly(2-hydroxyethyl methacrylate) (pHEMA). Given that the principles we derive can be broadly applied to potentially control various chemobrionic systems, this work paves the way for fabricating multifunctional materials that may hold great potential in a variety of application areas, such as regenerative medicine, catalysis and microfluidics.

Integral Equations Related to Volterra Series and Inverse Problems: Elements of Theory and Applications in Heat Power Engineering

The paper considers two types of Volterra integral equations of the first kind, arising in the study of inverse problems of the dynamics of controlled heat power systems. The main focus of the work is aimed at studying the specifics of the classes of Volterra equations of the first kind that arise when describing nonlinear dynamics using the apparatus of Volterra integro-power series. The subject area of the research is represented by a simulation model of a heat exchange unit element, which describes the change in enthalpy with arbitrary changes in fluid flow and heat supply. The numerical results of solving the problem of identification of transient characteristics are presented. They illustrate the fundamental importance of practical recommendations based on sufficient conditions for the solvability of linear multidimensional Volterra equations of the first kind. A new class of nonlinear systems of integro-algebraic equations of the first kind, related to the problem of automatic control of technical objects with vector inputs and outputs, is distinguished. For such systems, sufficient conditions are given for the existence of a unique, sufficiently smooth solution. A review of the literature on these problem types is given.

Development of evolutionary search algorithms with binary choice relations when making decisions for pellet tubular heaters

A study was carried out and the optimization process was carried out for one of the types of equipment for autonomous heat supply using renewable resources – a tubular pellet heater. The research is expedient, since there is no mathematical model of the unit operation for the pellet combustion unit, there is only a set of experimental results indicating the inconsistency of the criteria presented to it. As a result of the research, new algorithms have been obtained: firstly, an algorithm for selecting (multi-criteria optimization) the operating mode of the unit for burning pellets of tubular heaters, and secondly, algorithms for choosing, according to several criteria, the parameters of the heat exchange unit of a tubular heater with a screen. A set of algorithms for multicriteria optimization with binary selection ratios has been developed for tubular pellet heaters in full, including a pellet combustion unit and a heat exchange unit. Selection functions have been defined for a pellet combustion unit using dimensionless complexes based on experimental results. For a block of a tubular heat exchanger with a screen, a selection function is built taking into account the criteria of functioning and a mathematical model of the heater in the form of a system of nonlinear ordinary differential equations. The practical significance of the algorithm for selecting the operating mode for the pellet combustion unit lies in the possibility of obtaining the most preferable (optimal, taking into account many criteria) parameters in the entire range of permissible parameters, and not only among the experiments carried out. The practical significance of optimization algorithms for a heat exchange unit lies in the ability to select specific parameter values during design – the thermal power of the heater, air flow, the length of the tubular part and the screen, their diameters, taking into account several selection criteria.

A digital contract for restoration of the Earth System mediated by a Planetary Boundary Exchange Unit

In this paper, we propose a new governance paradigm for managing the Earth System based on a digital contract inspired on blockchain technology. This proposal allows for a radical decentralisation of the procedures of controlling, maintaining and restoring ecosystems by a set of networks willing to engage in improving the operational conditions of local ecosystems so to contribute to an optimal functioning of the Earth System. These procedures are aimed to improve local Planetary Boundary parameters so that they approach the optimal Holocene reference values, the so-called Safe Operating Space, via a reciprocal validation process and an exchange unit that internalises the state of the Earth System.

The effect of recuperator on the efficiency of ORC and TFC with very dry working fluid

Organic Rankine Cycles (ORC) and Trilateral Flash Cycles (TFC) are very similar power cycles; ideally, they have a reversible adiabatic (isentropic) compression, an isobaric heating, an isentropic expansion and an isobaric cooling. The main difference is that for ORC, the heating includes the full evaporation of the working fluid (prior expansion); therefore, the expansion starts in a saturated or dry vapour state, while for TFC, the heating terminates upon reaching the saturated liquid states. Therefore, for TFT, expansion liquid/vapour state (in bubbly liquid or in vapour dispersed with droplets), requiring a special two-phase expander. Being ORC a more “complete” cycle, one would expect that its thermodynamic efficiency is always higher than for a TFC, between the same temperatures and using the same working fluids. Surprisingly, it was shown that for very dry working fluids, the efficiency of TFC can exceed the efficiency of basic (i.e. recuperator- and superheater-free) ORC, choosing sufficiently high (but still subcritical) maximal cycle temperature. Therefore in these cases, TFC (having a simpler heat exchange unit for heating) can be a better choice than ORC. The presence of a recuperator can influence the situation; by recovering the proper percentage of the remaining heat (after the expansion), the efficiency of ORC can reach and even pass the efficiency of TFC.

Alveolar cells under mechanical stressed niche: critical contributors to pulmonary fibrosis

Pulmonary fibrosis arises from the repeated epithelial mild injuries and insufficient repair lead to over activation of fibroblasts and excessive deposition of extracellular matrix, which result in a mechanical stretched niche. However, increasing mechanical stress likely exists before the establishment of fibrosis since early micro injuries increase local vascular permeability and prompt cytoskeletal remodeling which alter cellular mechanical forces. It is noteworthy that COVID-19 patients with severe hypoxemia will receive mechanical ventilation as supportive treatment and subsequent pathology studies indicate lung fibrosis pattern. At advanced stages, mechanical stress originates mainly from the stiff matrix since boundaries between stiff and compliant parts of the tissue could generate mechanical stress. Therefore, mechanical stress has a significant role in the whole development process of pulmonary fibrosis. The alveoli are covered by abundant capillaries and function as the main gas exchange unit. Constantly subject to variety of damages, the alveolar epithelium injuries were recently recognized to play a vital role in the onset and development of idiopathic pulmonary fibrosis. In this review, we summarize the literature regarding the effects of mechanical stress on the fundamental cells constituting the alveoli in the process of pulmonary fibrosis, particularly on epithelial cells, capillary endothelial cells, fibroblasts, mast cells, macrophages and stem cells. Finally, we briefly review this issue from a more comprehensive perspective: the metabolic and epigenetic regulation.

Cooling of the Tehnical Objects Using Water-Evaporation Coolers

Постановка задачи. Рассматривается задача охлаждения воздуха технических объектов с помощью водоиспарительных охладителей рекуперативного принципа действия. Результаты. Выводится уравнение нестационарного теплового баланса ограниченного объема с технологическим оборудованием с учетом его охлаждения рекуперативными водоиспарительными охладителями. Представлены математическая модель теплофизических процессов в косвенных водоиспарительных воздухоохладителях рекуперативного принципа действия и метод ее реализации. Модель содержит дифференциальные уравнения в частных производных, описывающие перенос энергии и массы в каналах теплообменного блока. Выводы. В результате проведенных исследований установлено, что установки водоиспарительного охлаждения косвенно-рекуперативного типа позволят, не повышая влагосодержания воздуха, значительно снизить температуру в помещениях с технологическим оборудованием, выделяющим большое количество тепла. Экологическая чистота и невысокая стоимость охладительных установок подобного типа добавляют положительный эффект от их применения. Statement of the problem. The problem of air cooling of technical objects by means of water-evaporative coolers of the recuperative principle of action is considered. Results. The equation of unsteady thermal balance of limited volume with technological equipment is derived taking into account its cooling by recuperative water-evaporative coolers. The mathematical model of thermal physical processes in indirect water-evaporative air coolers of the recuperative principle of action and the method of its implementation are presented. The model contains partial differential equations describing the transfer of energy and mass in the channels of the heat exchange unit. Conclusions. As a result of the conducted studies, it is established that installations of water-evaporative cooling of indirect-recuperative type will allow one without increasing moisture content of air to considerably to reduce the temperature in rooms with the processing equipment allocating a large amount of heat. Environmental friendliness and a low cost of cooling units of this type add a positive effect from their application.

Low-cost microwave reactor for green synthesis of nanomaterials

Introduction: This contribution is about a low-cost microwave reactor for green synthesis of nanomaterials. The paper reflects research results achieved at the NanoFab group of the Universidad Militar Nueva Granada, within the line of nanophotonics, sensors and nanotechnology. Investigations and analyses were carried out during 2019. Problem: Conventional synthesis processes usually affect the environment and human health, due to contaminant reagents and generation of by-products. Objective: The aim of this research is the modification of a microwave oven that assists in the green synthesis of nanomaterials with potential applications in homeland security. Methodology: In this investigation, the modification of a domestic microwave was carried out. The implemented reactor features a heat exchange unit to reduce volatile elements, and a digital magnetic stirrer for local homogenization. Synthesis begins with a trisodium-citrate solution, continuously stirred at 37 °C. Next, the precursor is mixed with silver-nitrate for 2 minutes. Then, the mixture was treated for 20 minutes in the microwave reactor. Finally, the nanoparticles are recovered. Results: The homemade microwave reactor is suitable for producing nanoparticles. Particularly, the 20-minute microwave exposure time for the reactants results in a nanoparticle size between 80-90 nm. To probe reaction parameters, impedance spectroscopy analysis is performed. Results revealed that the resistance of the medium of silver nanoparticles is 2.5 ohms, while for sodium citrate and nitrate it is 8.8 and 11.8 ohms, respectively. Conclusion: It is demonstrated that the modified microwave reactor is suitable for nanomaterial production. Lower amounts of solvent are required during nanoparticle synthesis. Microwave synthesis allows for green nanomaterials production with a minor impact on the environment. Limitation: Homogeneous heating of reactants in a stationary microwave cavity is limited to waveguide design; in this case, to a multimodal-microwave waveguide. Originality: Low-cost reactor for nanomaterial production and greener synthesis.