Assessment of drillability of rocks is vital in the selection,operation,and performance evaluation of cutting tools used in various excavation machinery deployed in mining and tunneling.The commonly used rock drillabi...Assessment of drillability of rocks is vital in the selection,operation,and performance evaluation of cutting tools used in various excavation machinery deployed in mining and tunneling.The commonly used rock drillability prediction methods,namely,drilling rate index(DRI)and Cerchar hardness index(CHI)have limitations in predicting the penetration rate due to differential wear of the cutting tool in rocks with varied hardness and abrasivity.Since cutting tools get blunt differently in different rocks,the stress beneath the tip of the bit decreases until it reaches a threshold value beyond which the penetration rate becomes constant.In this research,a new composite penetration rate index(CPRI)is suggested based on the investigations on four metamorphic rocks viz.quartzite,gneiss,schist and phyllite with varied hardness-abrasivity values.The penetration-time behavior was classified into active,moderate,passive,and dormant phases based on the reduction in penetration rate at different stages of drilling.A comparison of predicted penetration rate values using DRI and CPRI with actual penetration rate values clearly establishes the supremacy of CPRI.Micro-structure and hardness-based index was also developed and correlated with CPRI.The new indices can help predict cutting tool penetration and its consumption more accurately.展开更多
分布式基站的基本结构与传统一体化基站有很大的不同,它将基站的基带部分(BBU/REC)和射频部分(RRU/RE/RRH)分离,分别作为单独的部分。这种分布式结构具有配置灵活、工程建设方便、环境适应性强等优点,应用越来越广泛。为了规范BBU和RRU...分布式基站的基本结构与传统一体化基站有很大的不同,它将基站的基带部分(BBU/REC)和射频部分(RRU/RE/RRH)分离,分别作为单独的部分。这种分布式结构具有配置灵活、工程建设方便、环境适应性强等优点,应用越来越广泛。为了规范BBU和RRU之间的接口标准,CPRI(Common Public Radio Interface)协议应运而生。目前,CPRI接口的测试已经成为业界关注的焦点。R&S公司基于其强大的技术实力,于业界首先推出了基于CPRI接口的RRU和BBU测试解决方案,进一步完善了基站领域的测试需求,可以更好地为运营商、基站设备商、直放站厂商和检测机构提供相应的测试服务。展开更多
基金Authors thank the CPRI Project(NPP/2016/HY/1/13042016)for partially supporting the study.Support from NHPC Ltd.and NTPC Ltd.is also thankfully acknowledged.
文摘Assessment of drillability of rocks is vital in the selection,operation,and performance evaluation of cutting tools used in various excavation machinery deployed in mining and tunneling.The commonly used rock drillability prediction methods,namely,drilling rate index(DRI)and Cerchar hardness index(CHI)have limitations in predicting the penetration rate due to differential wear of the cutting tool in rocks with varied hardness and abrasivity.Since cutting tools get blunt differently in different rocks,the stress beneath the tip of the bit decreases until it reaches a threshold value beyond which the penetration rate becomes constant.In this research,a new composite penetration rate index(CPRI)is suggested based on the investigations on four metamorphic rocks viz.quartzite,gneiss,schist and phyllite with varied hardness-abrasivity values.The penetration-time behavior was classified into active,moderate,passive,and dormant phases based on the reduction in penetration rate at different stages of drilling.A comparison of predicted penetration rate values using DRI and CPRI with actual penetration rate values clearly establishes the supremacy of CPRI.Micro-structure and hardness-based index was also developed and correlated with CPRI.The new indices can help predict cutting tool penetration and its consumption more accurately.
文摘分布式基站的基本结构与传统一体化基站有很大的不同,它将基站的基带部分(BBU/REC)和射频部分(RRU/RE/RRH)分离,分别作为单独的部分。这种分布式结构具有配置灵活、工程建设方便、环境适应性强等优点,应用越来越广泛。为了规范BBU和RRU之间的接口标准,CPRI(Common Public Radio Interface)协议应运而生。目前,CPRI接口的测试已经成为业界关注的焦点。R&S公司基于其强大的技术实力,于业界首先推出了基于CPRI接口的RRU和BBU测试解决方案,进一步完善了基站领域的测试需求,可以更好地为运营商、基站设备商、直放站厂商和检测机构提供相应的测试服务。
