Deterring effects of 8-45 kHz tone pulses on harbour seals (Phoca vitulina) in a large pool     

Kastelein RA  van der Heul S  Terhune JM  Verboom WC  Triesscheijn RJ 《Marine environmental research》2006,62(5):356-373

The marine aquaculture industry suffers losses due to pinniped attacks which damage net enclosures and fish stocks. Acoustic harassment devices (AHDs) emit loud sounds which are intended to deter pinnipeds from approaching aquaculture enclosures. At present, many AHDs emit sounds in the 8-20 kHz frequency range. It is not known whether sounds of higher frequencies have a deterrent effect on seals. Therefore five captive harbour seals (Phoca vitulina) were subjected to four series of tone pulses together spanning a broad frequency range (8, 16, 32 and 45 kHz). Pulse duration was 250 ms and pulse interval was 5s. Each of the four sounds was made deterrent by increasing the amplitude. The seals reacted by swimming away from the sounds. The displacement effect of each sound was judged by comparing the animals' surface positions, and number of surfacings, during ten 45 min baseline periods with ten 45 min test periods per frequency (one frequency per day in rotation, 40 sessions in total). The seals were displaced by all four frequencies throughout the 40 trial days. The seals came to the surface more often when the test tones were produced than in the baseline periods. The initial displacement distances did not change over the 40 test days. This suggests that operating AHDs for only short periods will be more effective and less likely to result in habituation by the seals than operating them continuously. The discomfort threshold sound pressure level (SPL) was established for each of the four pulse frequencies. The acoustic discomfort threshold SPL is defined as the boundary SPL between the area that the animals generally occupied during the transmission of the sounds and the area that they generally did not enter during sound transmission. The discomfort threshold SPL may depend on the context.  相似文献   

全国地震前兆数据入库处理   总被引：2，自引：0，他引：2  

周克昌  庞丽娜  李鑫  纪寿文  田力 《地震》2006,26(4):59-66

详细介绍了前兆数据入库处理软件Doqzh的功能特点、 工作参数文件、 数据入库流程、 两种数据入库模式、 错误处理、 工作日志文件以及支持的观测日志文件格式等。 该软件可对多种前兆数据、 观测日志以及电子月报表等进行入库处理, 对数据入库操作进行优化, 大大提高了数据入库效率, 且实现了数据入库操作的全程自动化, 包括连接数据库服务器、 连接FTP服务器、 下载文件、 备份文件、 数据包解压缩、 入库、 记录数据压缩包统计信息、 退出程序等。 该软件是国家地震前兆台网中心数据处理系统的核心软件, 在国家地震前兆台网中心和多个省级前兆台网中心收到了很好的应用效果, 为全国地震前兆数据的汇集和共享以及中国地震局的大华北数据共享任务起到了关键的作用。  相似文献   

水平井测井解释技术综述   总被引：31，自引：6，他引：25       下载免费PDF全文

周灿灿  王昌学 《地球物理学进展》2006,21(1):152-160

水平井的大规模钻井和应用是二十世纪后期石油工业的一个亮点.水平井技术在新油田开发和老油田调整挖潜上成效显著,它可降低勘探开发成本、大幅度提高油气单井产能和采收率等.回顾了水平井及水平井测井解释发展历史,比较了垂直井和水平井测井及解释评价上的异同,分析了水平井测井环境以及测井解释所面临的问题,简述了一些水平井测井数据处理方法及综合解释中应注意的问题,最后根据我国目前的水平井测井解释现状分析了存在的问题,提出了今后发展的思路：以跟踪国外和创新发展国内水平井解释技术为目标,开展复杂条件下各种测井方法的正反演研究,研究各种环境影响因素的校正方法,注意多学科的交叉综合,结合垂直井测井解释经验和水平井测井的特点提高水平井测井解释水平.  相似文献   

多极子阵列声波测井资料在塔河油田酸压设计施工中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

高坤  陶果  马勇 《地球物理学进展》2006,21(4):1227-1231

由于塔河油田灰岩裂缝性储层非均质性强、横向连通性差,需要对其进行有效的酸化压裂改造以获得具有经济价值的油气产能.近几年来,多极子阵列声波测井仪（主要DSI和XMAC）已投入塔河油田测井现场服务,这些新的声波测井资料经合适的软件处理后可获的极为丰富的地层信息.本文讨论了我们编制的多极子阵列声波测井资料处理软件及其在塔河油田酸压设计施工中的应用.通过多极子阵列声波测井资料处理得到的岩石力学特性分析,确定了地层应力的大小和方向,计算出酸化压裂所需的压力以及压裂后压裂缝的高度.计算结果在实际施工中得到了很好验证.  相似文献   

应力扰动对断层摩擦声发射活动影响的实验研究          下载免费PDF全文

马胜利  缪阿丽  黄元敏 《地震工程学报》2011,33(1):1-8,19

利用中尺度岩石摩擦实验开展了应力扰动对断层摩擦滑动过程中声发射活动影响的实验研究,据此讨论同震应力变化引起的小震活动特征及其预测意义.实验结果表明方波状应力扰动对粘滑失稳前的声发射活动有明显影响,即触发了一些声发射事件,使得粘滑发生前声发射活动增强并使出现的时间提前.这种影响随平均正应力的提高和扰动振幅的增大而增强,其...  相似文献   

Thermodynamical analysis of acoustic Schwarzschild black hole     

《New Astronomy》2024

In this paper, we analyze the thermodynamic properties of acoustic Schwarzschild black holes with its parameter. The study is conducted in the extended phase space displaying the phase transition. This phase transition is examined through Gibbs free energy, specific heat, and heat capacity. Later, we discuss the thermal stability of acoustic black holes through Hawking temperature by identifying their stable and unstable regions. We calculate the corrected entropy to examine the thermal fluctuations. Through the corrected entropy we observe that there is no fluctuation in the case of small black holes. We also discuss the energy emission process from acoustic black holes. Moreover, we employ the generalized uncertainty principle to obtain a modified Lagrangian equation. We analyze the tunneling and Hawking temperature of the acoustic Schwarzschild black hole after solving the field equations.  相似文献