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排序方式: 共有366条查询结果,搜索用时 93 毫秒
1.
Iratxe Perez-Arnedo María J. Cantalejo Alba Martínez-Laorden Elena Gonzalez-Fandos 《International Journal of Food Science & Technology》2021,56(4):1855-1864
Microbiological contamination of chicken meat depends on the conditions under which the animals are reared, slaughtered and processed. The aim of this study was to determine the influence of farm origin and processing stages at slaughterhouse on the microbial safety and quality of chicken. Samples of chicken carcasses from three different farms were taken from a slaughterhouse. Mesophiles, Escherichia coli, coagulase positive Staphylococcci counts, presence of Listeria monocytogenes,Campylobacter and Salmonella were determined at five sampling points: after defeathering, after evisceration, after washing, after chilling and after cutting. Chilling reduced log numbers of mesophiles, coagulase positive Staphylococci and E. coli by 0.85, 1.52 and 2.2 log units, respectively. Salmonella was not detected after chilling. High prevalence of Campylobacter spp was observed at all the stages ranging between 84% and 100%. L. monocytogenes was not detected in chicken carcasses after defeathering. However, it was detected after evisceration and after washing and chilling. The most critical stage for L. monocytogenes contamination was the portioning operation, the prevalence in breast and legs being 88% and 84%, respectively. 相似文献
2.
Sinéad C. Mac Namara Maria M. Garlock David P. Billington 《Canadian Metallurgical Quarterly》2007,21(2):152-156
Steam generator replacement at nuclear power plants requires large construction openings in nuclear containment structures. This study examines the effects of such openings placed in a 61?cm (2?ft) thick dome of a shield building. The dome is cast in two layers, and the limiting cases of the two layers acting as one and the lower layer carrying the entire load are considered. Without openings, the stresses due to dead load in the structure are very low when compared to the material strength. With openings, the loads are easily redistributed around the opening, and the maximum stresses for the conservative case are between three and four and one-half times larger than in the original structure with no openings. The extent of the affected area around the holes is relatively small. Smooth corners in the openings are necessary to avoid high local stress concentrations. 相似文献
3.
P. K. Chaviaropoulos I. G. Nikolaou K. A. Aggelis N. N. Soerensen J. Johansen M. O. L. Hansen Mac Gaunaa T. Hambraus Heiko Frhr. von Geyr Ch. Hirsch Kang Shun S. G. Voutsinas G. Tzabiras Y. Perivolaris S. Z. Dyrmose 《风能》2003,6(4):365-385
Aerodynamic modelling of HAWT rotors by means of “engineering methods” has reached a saddle point, where no further development can be expected without a breakthrough in understanding the physics of unsteady, rotating three‐dimensional flows. However, such a breakthrough becomes ever more necessary, as the size of the wind turbines increases. With the experimental work in that direction being mostly limited to observing the phenomena and interpreting the associated mechanisms, and its increased cost, alternatives are being sought. The use of CFD techniques and state‐of‐the‐art Navier–Stokes solvers is considered a very serious contender, a belief shared by the members of the present consortium, which has worked on the VISCEL JOR3‐CT98‐0208 Joule III project. This project's goal was to determine the aerodynamic characteristics as well as the aeroelastic behaviour of wind turbine blades across their broad range of operational conditions, from attached to highly separated flow regimes. The work programme included specific tasks for the validation and assessment of existing 3D solvers, for the parametric study of 3D flow around realistic blades and for the investigation of aeroelastic stability, at the blade section level. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
4.
Universal Access in the Information Society - Measurement of both usability and accessibility is an important concern in software development today. However, while a great amount of attention has... 相似文献
5.
Miguel A. Martínez-del-Amor Luis F. Macías-Ramos Luis Valencia-Cabrera Mario J. Pérez-Jiménez 《Natural computing》2016,15(4):565-573
Population Dynamics P systems are a type of multienvironment P systems that serve as a formal modeling framework for real ecosystems. The accurate simulation of these probabilistic models, e.g. with Direct distribution based on Consistent Blocks Algorithm, entails large run times. Hence, parallel platforms such as GPUs have been employed to speedup the simulation. In 2012, the first GPU simulator of PDP systems was presented. However, it was able to run only randomly generated PDP systems. In this paper, we present current updates made on this simulator, involving an input modu le for binary files and an output module for CSV files. Finally, the simulator has been experimentally validated with a real ecosystem model, and its performance has been tested with two high-end GPUs: Tesla C1060 and K40. 相似文献
6.
A. Ritacco R. Adam A. Adane P. Ade P. André A. Beelen B. Belier A. Benoît A. Bideaud N. Billot O. Bourrion M. Calvo A. Catalano G. Coiffard B. Comis A. D’Addabbo F.-X. Désert S. Doyle J. Goupy C. Kramer S. Leclercq J. F. Macías-Pérez J. Martino P. Mauskopf A. Maury F. Mayet A. Monfardini F. Pajot E. Pascale L. Perotto G. Pisano N. Ponthieu M. Rebolo-Iglesias V. Revéret L. Rodriguez G. Savini K. Schuster A. Sievers C. Thum S. Triqueneaux C. Tucker R. Zylka 《Journal of Low Temperature Physics》2016,184(3-4):724-732
7.
Ryan N. Smith Mac Schwager Stephen L. Smith Burton H. Jones Daniela Rus Gaurav S. Sukhatme 《野外机器人技术杂志》2011,28(5):714-741
Ocean processes are dynamic and complex and occur on multiple spatial and temporal scales. To obtain a synoptic view of such processes, ocean scientists collect data over long time periods. Historically, measurements were continually provided by fixed sensors, e.g., moorings, or gathered from ships. Recently, an increase in the utilization of autonomous underwater vehicles has enabled a more dynamic data acquisition approach. However, we still do not utilize the full capabilities of these vehicles. Here we present algorithms that produce persistent monitoring missions for underwater vehicles by balancing path following accuracy and sampling resolution for a given region of interest, which addresses a pressing need among ocean scientists to efficiently and effectively collect high‐value data. More specifically, this paper proposes a path planning algorithm and a speed control algorithm for underwater gliders, which together give informative trajectories for the glider to persistently monitor a patch of ocean. We optimize a cost function that blends two competing factors: maximize the information value along the path while minimizing deviation from the planned path due to ocean currents. Speed is controlled along the planned path by adjusting the pitch angle of the underwater glider, so that higher resolution samples are collected in areas of higher information value. The resulting paths are closed circuits that can be repeatedly traversed to collect long‐term ocean data in dynamic environments. The algorithms were tested during sea trials on an underwater glider operating off the coast of southern California, as well as in Monterey Bay, California. The experimental results show improvements in both data resolution and path reliability compared to previously executed sampling paths used in the respective regions. © 2011 Wiley Periodicals, Inc. 相似文献
8.
Jesús P. Mena-Chalco Ives Macêdo Luiz Velho Roberto M. Cesar Jr. 《The Visual computer》2009,25(10):899-909
In this paper, we present a 3D face photography system based on a facial expression training dataset, composed of both facial range images (3D geometry) and facial texture (2D photography). The proposed system allows one to obtain a 3D geometry representation of a given face provided as a 2D photography, which undergoes a series of transformations through the texture and geometry spaces estimated. In the training phase of the system, the facial landmarks are obtained by an active shape model (ASM) extracted from the 2D gray-level photography. Principal components analysis (PCA) is then used to represent the face dataset, thus defining an orthonormal basis of texture and another of geometry. In the reconstruction phase, an input is given by a face image to which the ASM is matched. The extracted facial landmarks and the face image are fed to the PCA basis transform, and a 3D version of the 2D input image is built. Experimental tests using a new dataset of 70 facial expressions belonging to ten subjects as training set show rapid reconstructed 3D faces which maintain spatial coherence similar to the human perception, thus corroborating the efficiency and the applicability of the proposed system. 相似文献
9.
10.
José A. Macías 《World Wide Web》2008,11(2):253-286
Since its emergence in the early 1990s, the WWW has become not only an information system of unprecedented size, but a universal
platform for the development of services and applications. However, most of the advances in web technologies are intended
for professional developers, paying poor attention to end-users with no programming abilities but with explicit needs of creating
and customizing web-based presentations. This provides a strong motivation for end-users to act as designers at some point,
leading to an emerging role of new computing-related professionals to be considered. This paper is an effort to leverage such
difficulties by providing intelligent mechanism to assist end-users in web-based authoring tasks. To carry out such a challenge,
intelligent user-monitoring techniques are exploited to obtain high-level information that will be used to infer the user’s
preferences and assist him throughout the interaction. Furthermore, we report on how iteration patterns can be applied to avoid repetitive tasks that are automatically carried out on behalf of the user. In order to bring off
a feasible trade-off between expressivity and ease of use, a user experiment to obtain the user’s perception and evaluate
the hit-rate of our system is also presented. 相似文献