Preparation and Properties of Sustainable Brake Pads with Recycled End-of-Life Tire Rubber Particles

Sustainable composite brake pads were processed by employing recycled end-of-life tire (ELT) rubber particles obtained by means of cryogenic grinding and ambient grinding. The effect of the grinding mechanism and concentration of ELT rubber particles was then reported. From the friction result test, better behavior in terms of coefficient of friction (COF) was obtained when 3% of ELT rubber particles were introduced into the composite. It was demonstrated that the size of the particles is not as determinant as the friction mechanism in the wear properties of the sustainable brake pads. Whereas, while increasing the ELT rubber particle size acts as detrimental to the COF either in the ambient or cryogenic grinding, at high friction distances, the better adhesion of the particles because of the rough surface of the particles subjected to ambient grinding enhances the long-life behavior of the composite brake pads.

Effect of Cryogenic Grinding on Fatigue Life of Additively Manufactured Maraging Steel

Additive manufacturing (AM) is replacing conventional manufacturing techniques due to its ability to manufacture complex structures with near-net shape and reduced material wastage. However, the poor surface integrity of the AM parts deteriorates the service life of the components. The AM parts should be subjected to post-processing treatment for improving surface integrity and fatigue life. In this research, maraging steel is printed using direct metal laser sintering (DMLS) process and the influence of grinding on the fatigue life of this additively manufactured material was investigated. For this purpose, the grinding experiments were performed under two different grinding environments such as dry and cryogenic conditions using a cubic boron nitride (CBN) grinding wheel. The results revealed that surface roughness could be reduced by about 87% under cryogenic condition over dry grinding. The fatigue tests carried out on the additive manufactured materials exposed a substantial increase of about 170% in their fatigue life when subjected to cryogenic grinding.

Trends in Grinding of Agroindustrial Products–A Literature review

Background: The milling of food in agro-industrial products has become an operation of high importance at a business, academic and research level. Objective: This article aims to present the results of a literature review on food milling, with the purpose to identify the most recent uses, types of mills, and new grinding trends. Methods: For this, a research equation was made with the keywords "grinding", "milling" and "food" in Scopus, which yielded as results 192 articles, 52 which are directly related to food, were analyzed. Results: Contributions were found in various types of grinding such as cryogenic grinding, nano-scaled grinding, ultrafine and superfine grinding. Conclusion: The authors highlighted the uses of these types of milling in Agro-industrial products such as nutmeg (Myristica fragrans), wheat bran (Triticum spp), ginger (Zingiber officinale) and green tea powder (Camellia sinensis), among others. It is observed that engineering texts dealing with theoretical and analytical food milling operations do not emphasize the new trends found. As a complementary part of this study, eight patents related to cryogenic grinding in food were analyzed, identifying uses of this type of grinding in coffee, lipids, lycopene, proteins, grains, and seeds; Besides, a query was carried out to find out commercial suppliers of cryogenic grinding equipment, in which six companies from China with their equipment were identified.

Comparison of volatile compounds in different parts of fresh Amomum villosum Lour. from different geographical areas using cryogenic grinding combined HS–SPME–GC–MS

Background The essential oil is one of the main active ingredients of Amomum villosum Lour. However, volatile compounds are easily lost during the drying, storage and even sample preparation procedure. Therefore, using fresh samples can obtain more accurately data for qualitative and comparative analysis. Methods In this study, the volatile compounds in different parts of fresh A. villosum from different origins were systemic analyzed and compared by using cryogenic grinding combined HS–SPME–GC–MS for the first time. GC–MS analyses were performed on a 6890 Series GC instrument coupled to a 5973 N mass spectrometer. The volatile compounds were extracted by the SPME fiber (100 μm PDMS). Analytes separation was achieved on a HP-5MS capillary column. The oven temperature was initially programmed at 70 °C, then raised 4 °C/min to reach 125 °C and then programmed at 0.5 °C/min to 133 °C, then at 6 °C/min to 170 °C and finally, at 20 °C/min to 280 °C held for 2 min. The temperatures of the injection port, ion source and transfer line were set at 250 °C, 230 °C and 280 °C, respectively. Results Forty-eight main compounds were identified in different parts of fresh A. villosum. The most abundant components in fresh fruit samples were camphor (3.91%), bornyl acetate (10.53%), caryophyllene (8.70%), β-bisabolene (11.50%), (E)-nerolidol (14.82%) and cubenol (10.04%). This is quite different with that of dried samples analyzed in our previous work. As different parts of the same plant, many common components with biological activities were detected in fruit and other parts. In principle components analysis (PCA) and hierarchical clustering analysis (HCA), four parts of A. villosum were divided into different groups clearly. Additionally, fruit and root samples also could be divided into two subgroups (HCA) in accordance with their regions. Conclusion The developed method was successfully used for qualitative and comparative analysis of volatile compounds in fresh A. villosum samples. Additionally, using fresh samples can obtain much more information which is helpful for their performance in the fields of functional foods, agriculture and biomedical industry. Furthermore, our research is helpful for comprehensive utilization and quality control of A. villosum.