Multi-Criteria Decision Approach to Design a Vacuum Infusion Process Layout Providing the Polymeric Composite Part Quality

The increasingly widespread use of vacuum assisted technologies in the manufacture of polymer-composite structures does not always provide the required product quality and repeatability. Deterioration of quality most often appears itself in the form of incomplete filling of the preform with resin as a result of the inner and outer dry spot formation, as well as due to premature gelation of the resin and blockage of the vacuum port. As experience shows, these undesirable phenomena are significantly dependent on the location of the resin and vacuum ports. This article presents a method for making a decision on the rational design of a process layout. It is based on early forecasting of its objectives in terms of quality and reliability when simulating its finite element model, on the correlation analysis of the preliminary and final quality assessments, as well as on the study of the cross-correlation of a group of early calculated sub-criteria. The effectiveness of the proposed method is demonstrated by the example of vacuum infusion of a 3D thin-walled structure of complex geometry.

Contact line dynamics on a substrate coated with a fluoropolymer

This work investigates the dynamics of the contact line during the propagation of a dry spot in a water layer on a solid substrate. The substrate is coated with fluoropolymer by using a hot wire chemical vapor deposition method. The dry spot is generated using a thermocapillary mechanism caused by the heating of the substrate from below by the laser. By analyzing schlieren images, the dependence of the velocity of the contact line during the propagation of a dry spot was obtained for various initial thicknesses of liquid films.

Numerical simulation of the formation of dry spots during film evaporation

This paper presents a developed methodology for calculating heat and mass transfer processes in a cylindrical evaporation cell. The mathematical model reproduces all significant features of the evaporation cell geometry. In this cell, a layer of liquid is formed on a substrate with a diameter of 51 mm, heated below. To simulate heat transfer during film evaporation on a heated substrate, a numerical technique based on the Volume of Fluid method was used. The developed model was used to study the process of dry spot formation during film evaporation. The calculated data are compared with the experiment on the profile of the free surface of the film during evaporation and rupture. In general, results of this testing demonstrated good agreement with experiment. As a result, it was shown that developed numerical method makes it possible to describe process of formation dry spots.

Macroscopic Diagnosis of Plant Diseases Caused by Pathogenic Microorganism

From a biological point of view, plant diseases are deviations from internal traits that cause plants to not be able to carry out normal growth activities. Plant diseases in the field can be identified based on signs and symptoms of diseases that appear. This study aims to determine how to diagnose macroscopically the symptoms of diseases that arise due to pathogenic microorganisms on plants. This research was conducted in 3 stages which included the location survey, observation, and primary data collection stages. The method for primary data collection is done by direct observation, namely direct observation of samples and documented. Data were analyzed using the formula to calculate the percentage and intensity of disease attacks on plants. The results obtained were as many as 3 plant species (Capsicum sp, Solanum escelentum, Oryza sativa) from 12 plants which were observed to be attacked by pathogenic microorganisms with a percentage amount (22,45 %, 58,97%, 9%). Obtain 4 types of pathogenic microorganisms that attack plants, namely Gemini virus that causes leaf curling in Capsicum sp plant, Pyricularia oryzae fungus which causes leaf blast in Oryza sativa plants, the fungus Alternaria solani causes dry spot and Rhizoctonia solani fungus which causes leaf blast in Oryza sativa plants, the fungus Alternaria solani causes leaf dry spot and Rhizoctonia solani fungi that cause fruit rot in Solanum escelentum.

Thermocapillary rupture of a horizontal liquid layer on a silicon substrate

This paper is an experimental study of thermocapillary breakdown phenomenon in a horizontal film of liquid placed on a silicon nonisothermal substrate. With the help of a high-speed video camera the speed of the three-phase contact line was measured during the growth of a dry spot.

The nucleate boiling in a droplet of aqueous salt solution

This paper is devoted to an experimental study of the dynamics of the nucleate boiling in a droplet of aqueous solution of LiBr salt. As the concentration of LiBr salt increases, the growth rate of the bubbles decreases and the boiling completely stops when a high salt concentration is reached. An increase in the concentration of salt in the liquid layer of the bottom of the bubble leads to a decrease in the rate of increase in the diameter of the bubble, and a dry spot is not formed. The growth rate of a bubble (v) in a water droplet is somewhat higher than one for a salt solution for t > 0.2-0.3 s. The difference of v for the salt solution from curve 3 increases sharply when t < 0.1 s. For the first time, four regimes of the nucleate boiling in LiBr solution droplet were detected.