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31.
Alvaro J. Romera Gil Levy Pierre C. Beukes Dave A. Clark Chris B. Glassey 《Nutrient Cycling in Agroecosystems》2012,92(3):329-346
On New Zealand dairy farms, it is the nitrogen excreted directly onto pasture, particularly urine, that drives nitrogen (N)
leaching from the farm. A new framework (UPF: Urine Patch Framework) is presented that post-processes the results of a whole
farm model and runs a mechanistic soil model to simulate the urine patches. Two alternative methods to simulate the spatial
distribution of urine patches were implemented and compared (Grid: spatially explicit, and Probabilistic: based on the probability of different temporal urination patterns). This paper describes the implementation of these two
methods in connection with a Whole Farm Model; and compares the N leaching predictions with observed data. Two examples are
provided, one analyzing the impact of urine patch overlap and another, the relative risk of N leaching at different times
of urinary N deposition. The model showed good correlation and predictive ability between simulated annual N leaching results
and observed data [R2 = 94 %, mean relative prediction error (MRPE) = 10 % for Grid and R2 = 72 %, MRPE = 20 % for Probabilistic]. The two methods produced similar results across an 8-year period for monthly and annual N leaching (R2 = 96 %, MRPE = 10 % and R2 = 86 %, MRPE = 8 %; respectively). Only 8 % of the paddock area was covered with multiple urinations during 1 year, but as
much as 39 % of the total urine volume was deposited on overlapped patches. Systematically removing all urinary N for 1 month
in either May or June reduced N leaching by approximately 20 %. Avoiding urinary N deposition during autumn or early winter
could be highly effective in mitigating N leached during the following winter. 相似文献
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Dave Randall 《Computer Supported Cooperative Work (CSCW)》2016,25(4-5):409-423
Tenenberg, Roth, and Socha’s paper “From I-awareness to we-awareness in CSCW” is, or should be, of special significance to those in the CSCW and HCI communities with more than a passing interest in the theoretical issues that underpin our work. It can be argued, and I would be a proponent of this view, that fundamental intellectual disagreements too seldom get an airing in our community, perhaps because it is in large part conference driven. Because of this, underlying perspectival disagreements can appear rather arcane. One of the great merits of the contributions to this special issue, I hope and believe, is that they will appear less so after careful reading. 相似文献
36.
The study focuses on hydrogen production from steam reforming of glycerol over nickel based catalyst promoted by zirconia and supported over ceria. Catalyst was prepared by the wet-impregnation method and characterized by BET surface area analysis, X-ray diffraction technique and scanning electron microscopy (SEM) analysis. The performance of the catalyst was evaluated in terms of hydrogen yield, selectivity and glycerol conversion at 700 °C in a tubular fixed bed reactor. The effect of glycerol concentration in feed, space time (W/FAO), temperature and time on stream (TOS) was analyzed for the catalyst Ni–ZrO2/CeO2 which showed the complete conversion of glycerol and high H2 yield that corresponds to 3.95 mol of H2 out of 7 mol. Thermodynamic analysis was also carried out using Aspen HYSYS for system having glycerol concentration 10 wt% and 20 wt% and experimental results were compared with thermodynamics. Kinetic study was carried out for the steam reforming of glycerol over Ni–ZrO2/CeO2 catalyst using the power law model. The values of activation energy and order of reaction were found to be 43.4 kJ/mol and 0.3 respectively. 相似文献
37.
让周遭的系统能够自动感测环境变化并做出反应,势必将对于人类的生活造成重大改变。无线传感器网络是多个分布式传感器实作(节点)组成的系统,能够共同透过相互无线通信的方式响应实体变化。本文将重点介绍节点的最新进展,并推广对于系统层级设计方法的需求。 相似文献
38.
The concept of territoriality and its relationship to the focus and substance of spatial planning is the subject of much interest at the present time and this paper seeks to contribute to the debate by stepping into the sea. The first part of the paper establishes a framework for considering the spatial planning implications of changing conceptions of territoriality, outlining key sources of territorial innovation and their implications in terms of the development of new units and styles of governance, new challenges for planning practice, and the potential for feedback informing the development of planning theory. The application of the framework is then illustrated in the second part of the paper with reference to the emerging field of maritime spatial planning and in particular to the pioneering work that is being undertaken in Europe. This work is testing established notions of territoriality by highlighting the strong and growing connections between the land and the sea. Here some of the key implications for future spatial planning practice are identified. These indicate that there is a growing recognition of the need for innovation in the territorial units of governance in maritime regions and in the themes, processes and methods of spatial planning in these areas. The paper concludes with some observations on the implications of these findings for the theory of spatial planning. 相似文献
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Grimshaw Andrew Morgan Mark Merrill Duane Kishimoto Hiro Savva Andreas Snelling David Smith Chris Berry Dave 《Computer》2009,42(2):27-34
To expand the use of distributed computer infrastructures as well as facilitate grid interoperability, OGSA has developed standards and specifications that address a range of scenarios, including high-throughput computing, federated data management, and service mobility. 相似文献