Diseño y construcción de un secador solar para el secado de madera de baja densidad

The purpose of this research was to demonstrate that the use of residual oil as a heat transport fluid and the use of rice husk as a thermal insulator is an efficient alternative for the greater use of solar energy. For this, a prototype of a solar dryer was designed and built consisting of a flat solar thermal concentrator and a parabolic cylindrical thermal concentrator (CCP), this was validated by drying Guazuma crinita, Mart. (White ball) and monitored by a contact hygrometer. Five tests were carried out, the first test was considered as a control, in which heat transport fluid and thermal insulators were not used, and in the following four tests two types of heat transport fluids were combined (residual motor oil and brine) and two types of thermal insulators (wood sawdust and rice husk), obtaining as a result that the most efficient test was number three, consisting of residual motor oil as heat transport fluid and rice husk as thermal insulator. With the most efficient test, the prototype was validated by drying low-density wood, reducing the humidity of the wood from 45.8% to 12.3% in ten sunny days.

Gallium–indium nanoparticles as phase change material additives for tunable thermal fluids

Inorganic Ga–In alloy nanoparticles suspended in a traditional thermal transport fluid simultaneously increase the overall thermal diffusivity of the fluid and serve as a cyclable solid–liquid PCM slurry, providing a thermal sink definable over a wide temperature range.

Ultrasonic Transducer Array Performance for Improved Cleaning of Pipelines in Marine and Freshwater Applications

Fouling accumulation in pipelines is a well-known problem in industry across various applications. The build-up of fouling within a pipe can reach a detrimental state, leading to pipe blockages that, in turn, result in pipe bursts. As pipelines transport fluid up to hundreds of meters, a method to prevent and remove fouling at long distances is required to support an engineering structure without the requirement of halts for maintenance to be carried out. Underwater pipelines are currently deployed which must ensure that pipelines carrying crude oil do not reach a detrimental state which leads to pipe leaks or pipe bursts, resulting in a discharge of oil into the surrounding water. This work discusses an optimized ultrasonic cleaning transducer array which undergoes marinization. The marinized transducers are characterized for impedance and wave propagation across a fouled 6.2 m long, Schedule 40, 6-inch diameter carbon steel pipe. This study has shown that the addition of marinized material dampens the vibrational output from the High-Power Ultrasonic Transducer (HPUT) configuration. This reduction in vibration is most significant when the structure is filled with water, resulting in a marinized HPUT configuration dropping by up to 85% and a non-marinized HPUT configuration dropping by up to 80%.

Droplets for Sampling and Transport of Chemical Signals in Biosensing: A Review

The chemical, temporal, and spatial resolution of chemical signals that are sampled and transported with continuous flow is limited because of Taylor dispersion. Droplets have been used to solve this problem by digitizing chemical signals into discrete segments that can be transported for a long distance or a long time without loss of chemical, temporal or spatial precision. In this review, we describe Taylor dispersion, sampling theory, and Laplace pressure, and give examples of sampling probes that have used droplets to sample or/and transport fluid from a continuous medium, such as cell culture or nerve tissue, for external analysis. The examples are categorized, as follows: (1) Aqueous-phase sampling with downstream droplet formation; (2) preformed droplets for sampling; and (3) droplets formed near the analyte source. Finally, strategies for downstream sample recovery for conventional analysis are described.

Flow topology of helical vortices

Equal coaxial symmetrically located helical vortices translate and rotate steadily while preserving their shape and relative position if they move in an unbounded inviscid incompressible fluid. In this paper, the linear and angular velocities of this set of vortices ($U$ and $\unicode[STIX]{x1D6FA}$ respectively) are computed as the sum of the mutually induced velocities found by Okulov (J. Fluid Mech., vol. 521, 2004, pp. 319–342) and the self-induced velocities found by Velasco Fuentes (J. Fluid Mech., vol. 836 2018). Numerical computations of the velocities using the Helmholtz integral and the Biot–Savart law, as well as numerical simulations of the flow evolution under the Euler equations, are used to verify that the theoretical results are accurate for $N=1,\ldots ,4$ vortices over a broad range of values of the pitch and radius of the vortices. An analysis of the flow topology in a reference system that translates with velocity $U$ and rotates with angular velocity $\unicode[STIX]{x1D6FA}$ serves to determine the capacity of the vortices to transport fluid.