Infrared Heating Technology for Automated Fiber Placement

Prepreg stickiness is the adhesion between prepregs or between a prepreg and a mold in lay-up process.It is critical for automated fiber placement,because the stickiness should be small for smooth transport,as well as large enough on the laying surface for a good placement performance.To ensure prepreg stickiness always being in the optimum laying window,placement temperature should be changed according to the laying speed.In our work,the relationship between laying speed and emissive power of heating lamp was studied.The heat transfer process between heating lamp and laying surface was analyzed and the control equation of dynamic temperature was derived.Finally,the infrared heating system was built and its effectiveness was verified based on placement experiment.

THERMOGRAPHIC ASPECT ON LOADING A THIN-WALL PRESSURE VESSEL STEEL

The infrared emission of a high pressure vessel steel and two thin wall pressure vessel models have been investigated by use of vibro-thermography.The experimental infrared crack lengths were found to be agreed closely with the optical values during fatigue process.A possi- ble nondestructive testing method used to evaluate the pressure vessel has been given.

Secondary cracking of volatile and its avoidance in infrared-heating pyrolysis reactor

This study aims to compare the pyrolysis behavior of Huadian oil shale in two infrared heating fixed bed reactors with different directions of infrared beam.Our previous work has shown that fast pyrolysis of oil shale conducted in the shallow fixed bed infrared heating reactor(co-current)presented the massive secondary reactions,which lowered the shale oil production(Siramard et al.,2017).Conversely,the cross-current infrared achieved shale oil yields higher than the Fischer Assay oil yield(13.07 wt%of dry basis),such as 117.7%of the Fischer Assay yield at our realized highest heating rate of 7℃/s under a specified pyrolysis temperature of 550℃.The shale oil from the cross-current infrared heating reactor was obviously heavier than the oil obtained from the cocurrent heating reactor.Thus,the infrared cross heating evidently suppressed the secondary reactions toward volatile.Our realized shale oil yield could reach 13.67 wt%or 122.5%of the Fischer Assay yield under reducing pyrolysis pressure of 0.6 atm,indicating that lower pressure is also beneficial to the release of volatile and reduction of the secondary cracking reactions.This work shows essentially that the infrared cross heating provides an effective merge of the advantages from quick heating and minimization of secondary cracking reactions to enable the shale oil yields being higher than the Fischer Assay oil yield.

An automated water dispensing system for controlling fires in coal yards

In spite of recent moves to wean the world of fossil fuels,coal remains the main source of power in many countries.Coal yards are prone to spontaneous ignition,a problem faced in every country that stores or transports coal.Depending on the environment-temperature,ventilation,and the rank of the coal-heating and self-ignition can be a longer or shorter process,but the possibility can never be entirely dismissed.A plethora of studies have modelled this oxidation behavior and proposed countermeasures.Most often,human intervention is necessary,which is both slow and dangerous for the frefghters involved.In this study,we propose to build a complete frefghting solution which is mounted on a number of towers sufcient to cover the area of an open coal yard,complete with redundancy.Each tower includes an inexpensive infrared detector,a water dispenser and a controller programmed to identify areas of elevated temperature,and actuate the dispenser.The heat direction algorithm calculates the parameters to position the water dispenser so that it covers the area.A prototype has been built from inexpensive components to demonstrate the efectiveness at detecting and extinguishing arising fres,and a solution has been costed for the coal yard in the case study.This work has been conducted in collaboration with the managers of the coal yard of a power plant.

Coupled heat and moisture transfer of a single mung bean grain based on IR heating

Infrared(IR)heating is often used for the treatment of liquid and solid foods.IR treatment is known to enhance their shelf life by reducing moisture content and inactivating the microorganisms.Mung bean(a type of pulse from India)is a short season crop;suffers maximum storage loss when compared to other legume grains.The losses are due to moisture and temperature movements.Drying of grains is an important postharvest operation.IR drying is advantageous over the conventional drying methods.In this paper,the drying of mung bean is considered.An experimental setup is developed to obtain the required moisture and temperature profiles.The equivalent model is simulated using COMSOL multiphysics software and the percentage error between the experimental and simulated models is calculated.Results of numerical implementation are presented and possible further extensions are identified.

Responses of Irrigated Winter Wheat Yield in North China to Increased Temperature and Elevated CO2Concentration

North China is one of the main regions of irrigated winter wheat production in China. Climate warming is apparent in this region, especially during the growing season of winter wheat. To understand how the yield of irrigated winter wheat in North China might be affected by climate warming and CO2 concentration enrichment in future, a set of manipulative field experiments was conducted in a site in the North China Plain under increased temperature and elevated CO2 concentration by using open top chambers and infrared radiator heaters. The results indicated that an average temperature increase of 1.7℃ in the growing season with CO2 concentration of 560 μmol mol-1 did not reduce the yield of irrigated winter wheat. The thousand- kernel weight of winter wheat did not change significantly despite improvement in the filling rate, because the increased temperature shortened the duration of grain filling. The number of effective panicles and the grain number per ear of winter wheat did not show significant changes. There was a large increase in the shoot biomass because of the increase in stem number and plant height. Consequently, under the prescribed scenario of asymmetric temperature increases and elevated CO2 concentration, the yield of irrigated winter wheat in North China is not likely to change significantly, but the harvest index of winter wheat is likely to be greatly reduced.

Nano Cr Interlayered CrN Coatings on Steels

CrN coated steels assisted with a nano Cr interlayer were investigated. The Cr nano-interlayers were prepared by sputter deposition with a thickness about 70-100 nm. CrN coatings were also prepared by sputter deposition on the Cr nano-interlayers. The crystal structures, microhardness, and scratch resistance of CrN/Cr coatings were determined. Results show that the Cr nano-interlayers improve scratch resistance and the microhardness of CrN coated steels. A rapid heat treatment with infrared （IR） was performed for coated specimens in the attempt to improve bonding, With IR heat treatments, the beneficial effect of the Cr nano-interlayers was clearly observed. Without the Cr nano-interlayers, severe cracks on the surface of coatings were observed after IR heat treatment. However, with a Cr interlayer, no cracks on the surface of CrN coatings were observed after the heat treatment. The scratch resistance of coatings was also affected by the Cr nano-interlayers. The scratch track was clean and showed significantly smaller amount of scratch debris for CrN coatings with Cr interlayers than those without the Cr nano-interlayers. The microhardness of coatings with the Cr nano-interlayers is higher than those without the Cr nano-interlayers after IR heat treatment. The Cr and CrN phase have been identified with X-ray diffraction analysis, and the results show that the higher the nitrogen content in the sputtering gas, the stronger the CrN peaks observed in the diffraction patterns are.