A New Inner Fabrication Method of Internal Cavity in Metal under Compound Acoustic Fields.

In order to realize direct manufacturing of cavity inside metal without assembly, this paper investigates the mechanism of cavity manufacturing inside metals under compound acoustic fields. First, a local acoustic cavitations model is established to study the single bubble generation at fixed point in Ga-In metal droplets, which has a low melting point. Second, cavitation-levitation acoustic composite fields are integrated with the experimental system for simulation and experimentation. Through COMSOL simulation and experimentation, this paper expounds the manufacturing mechanism of metal internal cavity under acoustic composite fields. The key problem is to control the duration of the cavitation bubble by controlling the driving acoustic pressure's frequency and the magnitude of ambient acoustic pressure. Under the condition of composite acoustic fields, this method realizes the direct fabrication of cavity inside Ga-In alloy for the first time.

A One-Dollar, Disposable, Paper-Based Microfluidic Chip for Real-Time Monitoring of Sweat Rate.

Collecting sweat and monitoring its rate is important for determining body condition and further sweat analyses, as this provides vital information about physiologic status and fitness level and could become an alternative to invasive blood tests in the future. Presented here is a one-dollar, disposable, paper-based microfluidic chip for real-time monitoring of sweat rate. The chip, pasted on any part of the skin surface, consists of a skin adhesive layer, sweat-proof layer, sweat-sensing layer, and scale layer with a disk-shape from bottom to top. The sweat-sensing layer has an impressed wax micro-channel containing pre-added chromogenic agent to show displacement by sweat, and the sweat volume can be read directly by scale lines without any electronic elements. The diameter and thickness of the complete chip are 25 mm and 0.3 mm, respectively, permitting good flexibility and compactness with the skin surface. Tests of sweat flow rate monitoring on the left forearm, forehead, and nape of the neck of volunteers doing running exercise were conducted. Average sweat rate on left forearm (1156 g·m-2·h-1) was much lower than that on the forehead (1710 g·m-2·h-1) and greater than that on the nape of the neck (998 g·m-2·h-1), in good agreement with rates measured using existing common commercial sweat collectors. The chip, as a very low-cost and convenient wearable device, has wide application prospects in real-time monitoring of sweat loss by body builders, athletes, firefighters, etc., or for further sweat analyses.

[Study on determination of sodium, vanadium and aluminum contents in fuel oil by ICP-AES].

The present paper considers synthetically all kinds of factors affecting excitation spectrum under traditional measurement conditions of fluorescence matter in liquor using plasma atomic emission spectra. The input power, carrier gas flow and assistant gas flow for BEC of Na, V, Al were optimized by testing. The input power, carrier gas flow and assistant gas flow for Na are 950 W, 0.6 L x min(-1) and 1.0 L x min(-1), respectively. The input power, carrier gas flow and assistant gas flow for V are 1 150 W, 0.5 and 1.1 L x min(-1), respectively. The input power, carrier gas flow and assistant gas flow for Al are 1 150 W, 0.6 and 1.0 L x min(-1), respectively. The result shows that the method is sensitive, accurate, linear in a wide range and highly precise. The precision is between 1.7%-2.2%, the linear ranges are between 0-100 mg x L(-1) and recoveries are between 96%-105%.