{"title":"Research on Stiffness Analysis and Technology of the Heavy Spidle Top","authors":"Yongkang Wang, Bing-Tuan Gao, Wenlong Han, Shilong Xue","doi":"10.2174/0126661454282437231227070831","DOIUrl":"https://doi.org/10.2174/0126661454282437231227070831","url":null,"abstract":"\u0000\u0000The spindle top is an important component used to withstand\u0000the shaft workpiece on machine tools so that the spindle can meet high efficiency and\u0000high precision requirements. However, the selection principles under various load\u0000conditions are not stipulated in use. In addition, material selection, manufacturing,\u0000heat treatment technology, etc., are of practical significance for the production of high\u0000hardness, high wear resistance, and high precision spindle tops.\u0000\u0000\u0000\u0000The spindle top type, material selection principles, heat treatment, cold\u0000working, and other manufacturing processes are given. Provide a reference for highperformance\u0000and top-notch design and manufacturing.\u0000\u0000\u0000\u0000The model of the spindle top will be created in UG software, then using\u0000ANSYS finite element analysis software to analyze stiffness of spindle top whose\u0000height-to-diameter ratios are 1:4 and 1:7 types in a variety of different load cases. The\u0000design and manufacturing process of the spindle top is analyzed and expounded from\u0000the selection and performance comparison of metal materials, heat treatment of different\u0000materials, cold manufacturing technology, and other aspects.\u0000\u0000\u0000\u0000The deformation laws of different types of spindle tops are obtained. According\u0000to the deformation regular, find the selection principle of height to diameter\u0000ratio of spindle top. The defects that are easy to occur in the technology are obtained\u0000and the preventive and solution measures are put forward.\u0000\u0000\u0000\u0000According to the deformation regular, find the selection principle of\u0000height to diameter ratio of spindle top. The material selection, heat treatment technology,\u0000and other technical research on the spindle top provide the necessary basis for\u0000the production of the spindle top.\u0000","PeriodicalId":36699,"journal":{"name":"Current Materials Science","volume":"5 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140505922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ramyakrishna Pothu, A. B. Radwan, Paramasivam Shanmugam, Aditya Saran, Hitler Louis, Rajender Boddula, Samuel Lalthazuala Rokhum, R. Naik, N. Al-Qahtani
{"title":"Tailoring Cu/Hydroxyapatite Catalysts for Selective Hydrogenolysis of\u0000Biomass Derived Levulinic Acid to γ-Valerolactone Biofuel Additive","authors":"Ramyakrishna Pothu, A. B. Radwan, Paramasivam Shanmugam, Aditya Saran, Hitler Louis, Rajender Boddula, Samuel Lalthazuala Rokhum, R. Naik, N. Al-Qahtani","doi":"10.2174/0126661454278665231219112020","DOIUrl":"https://doi.org/10.2174/0126661454278665231219112020","url":null,"abstract":"\u0000\u0000Sustainable synthesis of γ-valerolactone (GVL) from levulinic acid (LA) offers a sustainable approach to converting biomass-derived feedstocks into valuable chemicals and fuel additves. Cu-Hydroxyapatite (Cu-HAp) catalysts are potential candidates for vapor-phase hydrogenation of LA to GVL due to\u0000their enhanced catalytic activity and selectivity through Cu nanoparticle support.\u0000\u0000\u0000\u0000This study aimed to investigate the catalytic performance of Cu-HAp catalysts in the hydrogenation of levulinic acid to γ-valerolactone. The primary goal was\u0000to optimize reaction conditions and assess the enhanced catalytic activity and selectivity\u0000\u0000\u0000\u0000The influence of copper loading, reaction temperature, and catalyst stability\u0000was evaluated. Moreover, the effect of time on stream (TOS) on LA conversion and\u0000GVL selectivity was examined by the best optimised Cu/HAp catalyst.\u0000\u0000\u0000\u0000Cu-HAp catalysts exhibited favorable catalytic performance, with optimal\u0000conditions at approximately 5wt% copper loading. At this loading, maximum LA\u0000conversion (60%) and GVL selectivity (90%) were achieved after 8 hours on the\u0000stream at 265°C and 0.1 MPa conditions.\u0000\u0000\u0000\u0000The study demonstrates the efficacy of Cu-HAp catalysts for the hydrogenation of levulinic acid to γ-valerolactone. The findings indicate that as the copper\u0000loading increases from 2 to 20 wt%, the conversion of LA and the selectivity to GVL\u0000both decline. The analysis further implies that the dispersion of Cu species corresponds directly to the activity observed during the LA hydrogenation. The conversion\u0000of LA rises with a higher reaction temperature ranging from 250-320°C, although the\u0000selectivity of GVL decreases above 265°C. The catalyst's stability is crucial for maintaining efficient catalytic activity over time, with observed deactivation attributed to\u0000Cu metal particle aggregation and coke formation on active sites. The findings contribute to the development of robust catalyst systems for biomass-derived chemical\u0000transformations.\u0000","PeriodicalId":36699,"journal":{"name":"Current Materials Science","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139626921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}