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Everwide Newsletter No.221


Experiment § Compatibility study

We often wonder whether in addition to experimental proofs. Can we use theoretical thinking to help us make some conjectures, especially when some experiments are wasteful or challenging to execute? For example: use TGA to predict material life (213 periods) and predict strength changes (217 periods). Also, mechanical behavior, flow behavior may be indicated by theory. Do some customers want to know whether a particular epoxy resin formulation will be affected by refrigerant R-134a? The boiling point of this refrigerant at 1 atm is -26.3°C. We cannot design experiments to soak the epoxy resin into the refrigerant for observation. We use the theory of group contribution to calculate the refrigerant and the resin formula after the hardened solubility parameter. The refrigerant's solubility parameter is δ = 15.7 (MJ/m3)1/2, and the solubility parameter of the resin formulation after curing is above 23 (MJ/m3)1/2. From a chemical point of view, the two are highly incompatible. R-134a will not corrode this formula. The only consideration is the effect of the low temperature of the refrigerant on the resin. It is then much easier to observe the resin changes in a low-temperature environment separately, as long as the actual object is placed in the thermal shock machine.

─ Author: Dr. Ming-xu, Li, Mr. Zhan-yu, Chen

 

Activity § Experiment record book

R&D personnel has different ideas every day. To prevent the loss of these ideas, we design the experiment record book for recording the process. Starting from a development project, including; customer needs, colleagues' experience sharing, experimental design details until the end of the final development will be recorded in the book. Each record book is the fruitful result of the painstaking work of R&D personnel. When thinking about a difficult situation, he would go to the library to read previous records and look for literature. Some R&D companies will also produce "sample books" to observe the product changes in different periods. When the experiment record book was revised this year, we conducted a cover vote. Seeing the bookshelves full of record books represents the company's growth process and is also a shared memory for everyone.

 

Knowledge § What is adhesive failure? What is cohesive failure?

Adhesive failure refers to the interface between the adhesive and the substrate. When it fails, it is often seen that the adhesive separates from the substrate, and there is no adhesive residue on the substrate. We must think about how to promote the adhesion between the substrate and the adhesive. Cohesive failure refers to the adhesive's insufficient mechanical strength, which leads to the failure of the adhesive mechanism. When the cohesive failure, the adhesive is still firmly attached to the substrate, and the fracture surface occurs. At this time, it is necessary to think about improving the strength of the adhesive itself. Sometimes it is a mixed-mode of both, and we need to think about its causes. What kind of failure mode does the observation after the experiment belong to? It is very important for adhesive improvements. In the case of adhesive failure, it may not help increase the strength of the adhesive itself, or in the case of cohesive failure, to perform surface treatment on the substrate.

 

Living § Invisible killer

The hottest news in Yunlin last year was probably that the county council passed the "Autonomous Regulations on Prohibition of Burning Raw Coal and Petroleum Coke." Yunlin County is one of the counties with severely polluted suspended particulates in the air, and Douliu City is the most serious place in the county. The index is often the highest in Taiwan. I also have chronic sinusitis. I used to go to the hospital since I was a child. When I was in junior high school, I had surgery twice. Looking back now, is it related to poor air quality? 30% of the source of fine aerosols in Yunlin County is an overseas transmission, mainly related to the haze damage in mainland China. The remaining 70% is generated by local factories, construction sites, outdoor burning, and transportation. In particular, the raw coal consumption of Yunlin County accounts for 22% of the country (14 million metric tons/year), petroleum coke with high sulfur content, and high-sulfur fuel oil, all of which are the sources of the pollution. Suspended particles in the air are referred to as PM (particulate matter). The particle size of the PM is different. Particles less than or equal to 2.5μm are called PM2.5. Such fine particles can penetrate the air bubbles in the lungs and directly enter the blood vessels to circulate throughout the body. The impact on the human body and ecology cannot be ignored. When the PM2.5 index is high, outdoor activities should be avoided, and it is suggested to wear a mask when going out. In 1985, writer Ze-lai, Song, born in Yunlin, wrote a novel "Ruins of Taiwan," predicting that all rivers and rivers in Taiwan will be dead in 2010, the land will be polluted, and people will have to wear gas masks when they go out. It still seems worthy of our alert! With all the wealth but living in ruins, what could be more stupid than this?

─ Author: Mr. Yun-Xian, Liu


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