螺旋钻参数对挖坑出土效能的影响          下载免费PDF全文

巴利珍  吴海平  张前英  冯泽程  连萌 《农业工程》2022,12(1):103-108

为了解决螺旋钻挖坑作业中存在的效率低、效果不佳等问题,进行了螺旋钻田间挖坑试验,通过改变直径、螺旋数量和转速等螺旋钻参数进行挖坑及出土情况测试,测取了坑形、抛土半径和出土率等特征数据,运用单因素方差分析和析因设计方差分析等方法进行了试验数据处理.研究结果表明:转速一定的情况下,螺旋钻直径增大,抛土半径和出土率增大;增加...  相似文献   

COMPARISON BETWEEN COMPUTED TOMOGRAPHY,FLUOROSCOPY, AND ULTRASONOGRAPHY FOR GUIDING PERCUTANEOUS INJECTION OF THE CANINE INTERVERTEBRAL DISC     

Shawn D. MacKenzie  Jeff L. Caswell  Brigitte A. Brisson  Luis Gaitero  Heather J. Chalmers 《Veterinary radiology & ultrasound》2014,55(5):571-581

A minimally invasive method for delivering injectable therapeutic agents would be desirable for the treatment of intervertebral disc disease in dogs. The purpose of this study was to compare computed tomography (CT), ultrasonography (US), and fluoroscopy modalities for guiding percutaneous injection into canine intervertebral discs. Intervertebral discs of 14 dog cadavers were injected with a gelified ethanol therapeutic agent. Successful injectate placement and injectate leakage were determined based on necropsy inspection of discs. Injection into the nucleus pulposus was successful in 55 of 78 (71%) of all injected discs. Injections guided using CT and fluoroscopy were significantly more successful than US‐guided injections. Odds of successful injection without leakage were greater for CT vs. US (P = 0.0026) but there was no significant difference between CT and fluoroscopy (P = 0.0620). Injection success rates did not differ among vertebral sites or dog cadavers of varying weights. Forty‐nine (63%) of injection sites had injectate leakage outside the disc and 10 of these involved structures within the vertebral canal. The highest rate of injection success with the least amount of leakage was achieved with CT guidance. Findings indicated that CT, fluoroscopy, and US are feasible modalities for guiding percutaneous injection of a gelified ethanol therapeutic agent into the canine intervertebral disc, with moderate to high success rates for different regions of the spine. However, a moderately high rate of injectate leakage occurred outside of the disc and this should be taken into consideration for future safety and efficacy studies.  相似文献   

Presumptive cocaine toxicosis in 19 dogs: 2004–2012     

Emily K. Thomas BA  VetMB  MRCVS  Kenneth J. Drobatz DVM  MSCE  DACVIM  DACVECC  Deborah C. Mandell VMD  DACVECC 《Journal of Veterinary Emergency and Critical Care》2014,24(2):201-207

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优质高产啤酒大麦蒙啤麦7号的选育与栽培技术     

吕二锁  徐寿军  马宇  巴图  李建波  郭呈宇  刘志萍 《大麦与谷类科学》2022,39(2):65-67

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大数据时代农村信息服务的实例研究   总被引：1，自引：0，他引：1  

付伟铮  巴洪连  任爱胜 《农业网络信息》2014,(11):5-10

大数据时代,建立农村信息服务体系对促进农村经济发展和提高农民收入,加快农业现代化,推动农村城市化意义非常重要。本文分析了北京地区北臧村镇农业信息服务的工作现状,揭示了存在的问题,采用李克特量表和农村信息服务综合评价指标体系进行调研和量化分析,并针对农业信息服务提出了改进建议。  相似文献   

Treatment of Hydroponics Wastewater Using Constructed Wetlands in Winter Conditions   总被引：1，自引：0，他引：1  

Vincent Gagnon  Gabriel Maltais-Landry  Jaume Puigagut  Florent Chazarenc  Jacques Brisson 《Water, air, and soil pollution》2010,212(1-4):483-490

Hydroponics culture generates large amounts of wastewater that are highly concentrated in nitrate and phosphorus but contains almost no organic carbon. Constructed wetlands (CWs) have been proposed to treat this type of effluent, but little is known about the performance of these systems in treating hydroponic wastewater. In addition, obtaining satisfactory winter performances from CWs operated in cold climates remains a challenge, as biological pathways are often slowed down or inhibited. The main objective of this study was to assess the effect of plant species (Typha sp., Phragmites australis, and Phalaris arundinacea) and the addition of organic carbon on nutrient removal in winter. The experimental setup consisted of 16 subsurface flow CW mesocosms (1 m², HRT of 3 days) fed with 30 L?d¹ of synthetic hydroponics wastewater, with half of the mesocosms fed with an additional source of organic carbon (sucrose). Carbon addition had a significant impact on nitrate and phosphate removal, with removal means of 4.9 g m^-2?d^-1 of NO₃-N and 0.5 g m^-2 d^-1 of PO₄-P. Planted mesocosms were generally more efficient than unplanted controls. Furthermore, we found significant differences among plant treatments for NO₃-N (highest removal with P. arundinacea) and COD (highest removal with P. australis/Typha sp.). Overall, planted wetlands with added organic carbon represent the best combination to treat hydroponics wastewater during the winter.  相似文献   

Monitoring distances travelled by horses using GPS tracking collars     

BA Hampson  JM Morton  PC Mills  MG Trotter  DW Lamb  CC Pollitt 《Australian veterinary journal》2010,88(5):176-181

Objective The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results In the paddocks used (0.8–16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.  相似文献   

Positive immunostaining of ovine congenital progressive muscular dystrophy with antibody against N- and C-terminal dystrophin     

H NAKADA  PF JACOBSEN  RD JOHNSEN  BA KAKULAS 《Australian veterinary journal》1990,67(7):271-272

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紫花苜蓿自然株高变量分析   总被引：5，自引：0，他引：5  

白玉龙  姜永  巴雅尔  乌艳虹  陶红梅  韩晓华 《草业科学》2002,19(6):32-34

测定了9个紫花苜蓿品种生长高峰期的自然株高，统计分析结果表明，紫花苜蓿6－9周龄生长高峰期，各品种平均自然株高与株龄间呈非常显著（P＜0．01）或显著正相关，线性回归方程估测相对误差除Ranger大于5％外，其余线性回归方程估测相对误差均小于5％。第9周龄的Travois和皇后苜蓿平均自然株高显著不显著。第9周龄的Travois和皇后苜蓿平均自然株高显著（P＜0．05）高于对照品种敖汉苜蓿平衡自然株高，其余各参试品种与对照品种敖汉苜蓿比较，平均自然株高株不显著。第9周龄平均自然株高排序前4位的品种依次为Travois, 皇后苜蓿，Ranger,Baker。  相似文献   

Conservative management of minimally displaced radial fractures in three horses     

S. MATTHEWS  AJ DART  BA DOWLING  DR HODGSON 《Australian veterinary journal》2002,80(1):44-47

Minimally displaced, spiral, radial fractures were diagnosed in three adult horses. Two horses had open fractures and in one horse the fracture was closed. A diagnosis was made on radiographs taken 24 h, 5, and 9 days after the fracture. There was minimal displacement of the fracture fragments despite the considerable time which had elapsed between fracture and diagnosis and an unfavourable prognosis with internal fixation, so conservative therapy was the preferred method of treatment. One horse developed a sequestrum and draining sinus, which was treated surgically under general anaesthesia 3 months after diagnosis of the fracture. Other complications were minimal and transient. Two horses were being used for pleasure riding 12 months after fracture and one horse was pasture sound at 8 months.  相似文献