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排序方式: 共有73条查询结果,搜索用时 15 毫秒
1.
该文在旧桥改造维修中,对桥面垫层混凝土破坏机理及补强技术提出了一些看法和措施建议,可供工程实际应用参考。 相似文献
2.
模拟降雨下重庆喀斯特槽谷区径流氮磷元素流失特征 总被引:2,自引:0,他引:2
为揭示降雨强度和岩层倾向对喀斯特槽谷区耕层土壤氮磷流失的影响,利用人工降雨装置和可变坡钢槽进行模拟试验,设计坡面坡度为25°,岩石裸露率为15%,岩层倾角为30°,地下孔裂隙度为3%,降雨强度分别为30、60和90 mm/h,模拟降雨持续时间为1h.结果 表明:1)产流量随着降雨强度的增大而增大,地表产流量表现为裸坡>... 相似文献
3.
西南某水电站引水线路靠近厂房段为三叠系须家河组和雷口坡组构成的顺层坡。现场调查发现,浅表层存在一个由四个滑坡组成的滑坡群,从南到北滑坡编号依次为A、B、C和D。滑坡A、B主要由块碎石土组成,滑坡C主要由块碎石土夹保持原岩层序的岩块(假基岩)组成,滑坡D基本由假基岩组成。这些滑坡属滑移-拉裂、滑移-弯曲、倾倒变形破坏机制。岩层中的软弱层面及有效临空面是滑坡发育的基本条件;降雨或地震是重要的诱发因素。 相似文献
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为深入了解牛床垫料再生系统的工艺技术特点及对环境的影响程度,对垫料再生系统处理过程中物料特性和温室气体排放进行测试。结果表明:BRU系统的核心—发酵仓,其运行过程基本不改变物料的理化特性,随着出料流量的增大,仓内温度和CO_2、CH_4及N_2O的排放速率均显著降低,而相对湿度则明显提高;牛场粪污固液分离后经垫料再生系统处理,每1.00t牛粪的CO_2、CH_4、N_2O气体排放量分别为2.15~5.04kg、1.95~7.25g、27.09~58.11mg,1.00t鲜牛粪温室气体排放量相当于3.60kg CO_2当量。BRU系统和好氧发酵2种垫料生产系统的生命周期评价结果显示,BRU系统对环境影响远小于好氧发酵系统,仅为好氧发酵系统的9%,其环境友好性优于好氧发酵系统。 相似文献
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The performance (survival and growth) of Douglas-fir (Pseudotsuga menziesii Mirb. Franco.) seedlings planted in minimally disturbed, scalped, and bedded soils, both with and without herbicidal control of weeds, were compared. Douglas-fir growing for 3 years in bedded soils treated with herbicide were heavier, taller, and had deeper root systems than trees growing in other preparations. Scalping did not improve seedling performance when compared to minimally disturbed soils. Soils rich in organic matter benefited tree growth. Competing vegetation in raised beds was detrimental to seedling performance. 相似文献
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Shigeru NINOMIYA Masato AOYAMA Yumiko UJIIE Ryo KUSUNOSE Atsutoshi KUWANO 《Journal of Equine Science》2008,19(3):53-56
The objective of this study was to investigate the effect of straw, sawdust, coconut husk
(husk), and coconut fiber (fiber) on the welfare of stable horses by observing their
resting behavior. Twenty horses with ages ranging from 3 to 21 years were used at the
Equine Research Institute of the Japan Racing Association, Utsunomiya, Japan. Five horses
were allocated to each bedding condition. The behavior of each horse was recorded by video
camera for 3 days and was continuously sampled from 17:00 to 05:00. The total duration,
the number of bouts, and the mean and the maximum duration of bouts in standing rest,
sternal lying, and lateral lying were calculated and analysed by the Kruskal-Wallis test
and post hoc Steel-Dwass test. There was no difference in the standing rest and the
sternal lying among beddings. Significant differences were observed in these values in the
lateral lying among the different beddings (P<0.05). The values of the means of the
total duration, the number of bouts, and the mean and the maximum duration of bout in the
lateral lying were greater when husk was used as the bedding material than when sawdust
were used (P<0.05). The results of the observations show that the new bedding materials
would be as usable as straw. However, lateral lying was observed less frequently when
sawdust were used as bedding; this indicates that use of sawdust as bedding material will
decrease the welfare of stabled horses. 相似文献
10.
Sonnia Nzilani Musyoka David Liti Erick O. Ogello Paul Meulenbroek Herwig Waidbacher 《Aquaculture Research》2020,51(6):2359-2368
The study amalgamated earthworm and agro‐industrial wastes through vermicomposting and then evaluated the potential of the bedding (mixture of Eisenia fetida and vermicompost) to replace fishmeal in semi‐intensive farming of Oreochromis niloticus. The bedding was used to substitute fishmeal at inclusion rates of 100, 60, 30 and 0% (D100, D60, D30 and control D0). In triplicates, the four homogeneous diets were fed to quadruplicate groups of 30 g O. niloticus for 112 days. There was no significant difference (p > .05) in mortalities, average length gain and FCR among all tests. Nevertheless, diet D0 had significantly (p < .05) superior amino acid profile, low fibre content and fish carcass crude protein (63.2 ± 0.72% dry matter). Subsequently, D30 and D0 produced fish with significantly higher (p < .05) mean weight gain (256.03 ± 0.4 g) and biomass (369,136 g) respectively. On to the contrary, diet D100 had significantly higher (p < .05) crude lipids content (9.4 ± 0.6% dry matter), economic returns and profit index than the control diet due to the comparatively low cost of producing the earthworm bedding. This simple biotechnology can commercially be upscaled to sustainably produce cheap and nutritious fish feed capable of increasing yields and maximizing profits. 相似文献