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31.
A patient with end-stage renal disease presented with reflex sympathetic dystrophy syndrome (RSDS) on her left hand 1 month after arteriovenous fistula (AVF) surgery. Magnetic resonance angiography revealed steal syndrome at the AVF level. Bone scintigraphy revealed early-stage RSDS. We considered that arterial insufficiency because of steal phenomenon following AVF surgery and underlying occlusive arterial disease triggered RSDS development.  相似文献   
32.
For successful data delivery, the destination nodes should be listening to the medium to receive data when the sender node starts data communication. To achieve this synchronization, there are different rendezvous schemes, among which the most energy-efficient is utilizing wakeup receivers. Current hardware technologies of wake-up receivers enable us to evaluate them as a promising solution for wireless sensor networks. In this article the benefits achieved with wake-up receivers are investigated along with the challenges observed. In addition, an overview of state-of-the-art hardware and networking protocol proposals is presented. As wake-up receivers offer new opportunities, new potential application areas are also presented and discussed.  相似文献   
33.
34.
This paper deals with the periodic flow of a second-grade fluid caused by non-torsional oscillations of two disks rotating about non-coincident axes. While the two parallel disks are initially rotating with the same angular velocity about distinct axes, they start to execute non-torsional oscillations in their own planes and in the opposite directions. An exact solution is obtained for the components of the horizontal force per unit area exerted by the top and bottom disks on the fluid in the periodic state. The results are graphically displayed and the influence of the second-grade fluid parameter, the ratio of the frequency of oscillation to the angular velocity of the disks, the Reynolds number and the dimensionless velocity amplitudes of oscillation is discussed. It is observed that the change in the \( x \)-component of the mentioned force gets larger when the second-grade fluid parameter increases. However, an opposite effect is seen for the change in the \( y \)-component.  相似文献   
35.
A single rock type was drilled using two types of thermally stable polycrystalline diamond compact (PDC) and an impregnated diamond core bit using a fully instrumented laboratory drilling rig at a fixed rotational speed, and over a range of weights on bit (WOB). Operating parameters of the bits such as WOB, rate of penetration (ROP), rotational speed (RPM), torque and drilling specific energy (SE) were continuously monitored during the drilling trials. The effects of these parameters on the performance of the bits were examined. Relations between the drilling variables are also described. At each set WOB for each bit, the drilling detritus were collected. The detritus sizes between 1180 and 53 microns were analysed using wet sieving and sub 53 micron was analysed using a Malvern particle size machine. Both data were combined to obtain a particle size distribution at set WOBs for each bit. The relations between the particle size of the drilling detritus and operating parameters, cutter size and wear of the PDC and impregnated diamond core bits, and original rock grain size were established. An increase in WOB, ROP, wear rates, pins or diamond size increased the drilling detritus size for the bits. No relation was found between the drilling detritus and the rock grain size due to the regrinding effect and the high proportion (> 30%) of matrix material in the rock.  相似文献   
36.
The valuable aroma compound piperonal with its vanilla-like olfactory properties is of high interest for the fragrance and flavor industry. A lipoxygenase (LOXPsa1) of the basidiomycete Pleurotus sapidus was identified to convert piperine, the abundant pungent principle of black pepper (Piper nigrum), to piperonal and a second volatile product, 3,4-methylenedioxycinnamaldehyde, with a vanilla-like odor through an alkene cleavage. The reaction principle was co-oxidation, as proven by its dependence on the presence of linoleic or α-linolenic acid, common substrates of lipoxygenases. Optimization of the reaction conditions (substrate concentrations, reaction temperature and time) led to a 24-fold and 15-fold increase of the piperonal and 3,4-methylenedioxycinnamaldehyde concentration using the recombinant enzyme. Monokaryotic strains showed different concentrations of and ratios between the two reaction products.  相似文献   
37.
Location area planning and cell-to-switch assignment in cellular networks   总被引:1,自引:0,他引:1  
Location area (LA) planning plays an important role in cellular networks because of the tradeoff caused by paging and registration signalling. The upper boundary for the size of an LA is the service area of a mobile services switching center (MSC). In that extreme case, the cost of paging is at its maximum but no registration is needed. On the other hand, if each cell is an LA, the paging cost is minimal but the cost of registration is the largest. Between these extremes lie one or more partitions of the MSC service area that minimize the total cost of paging and registration. In this paper, we seek to determine the location areas in an optimum fashion. Cell to switch assignments are also determined to achieve the minimization of the network cost. For that purpose, we use the available network information to formulate a realistic optimization problem, and propose an algorithm based on simulated annealing (SA) for its solution. Then, we investigate the quality of the SA-based technique by comparing it to greedy search, random generation methods, and a heuristic algorithm.  相似文献   
38.
Harzendorf  F.  Wulf  C.  Haase  M.  Baumann  M.  Ersoy  H.  Zapp  P. 《Clean Technologies and Environmental Policy》2022,24(10):3145-3169

To strengthen the economic pillar in sustainability assessment, the indicator ‘domestic value added’ is introduced. It aims at comparing established and less developed technologies regarding their prospective value added in a country. This is done by classifying a technology’s value added to the developed categories: domestic, potential domestic and non-domestic. Within this paper, two methods for assessing this indicator are introduced focussing on their applicability in a sustainability assessment context. Both methods are tested on a case study comparing two alternative drivetrain technologies for the passenger car sector (battery and fuel cell electric vehicle) to the conventionally used internal combustion engine. The first method is life cycle cost-based whereas the second is based on Input Output analysis. If a life cycle cost assessment is already available for the technology under assessment, the easier to implement life cycle cost-based approach is recommended, as the results are similar to the more complex Input Output-based approach. From the ‘domestic value added’ perspective, the battery electric vehicle is already more advantageous than the conventional internal combustion engine over the lifecycle. Fuel cell electric vehicles have the highest potential to increase their ‘domestic value added’ share in the future. This paper broadens the economic pillar in sustainability assessment by introducing a new indicator ‘domestic value added’ and giving practical information on how to prospectively assess it for existing and less developed technologies or innovations.

Graphical abstract
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39.
针对夜间车辆视频检测和车流量统计的难题,提出了一种改进的基于视频图像处理提取车前灯的算法。通过分析夜间车辆视频的特点,利用梯度滤波法消除地面反射光对车灯的干扰,实现图像增强,并将分水岭分割算法和直方图双峰法相结合提取车前灯的信息。利用车灯配对匹配原则设计了一种新的匹配算法和跟踪算法实现车灯的配对与跟踪,最终准确地实现了车辆检测和车流量的统计功能。  相似文献   
40.
Becoming mature enough to be used for improving the quality of life, wireless sensor network technologies are considered as one of the key research areas in computer science and healthcare application industries. The pervasive healthcare systems provide rich contextual information and alerting mechanisms against odd conditions with continuous monitoring. This minimizes the need for caregivers and helps the chronically ill and elderly to survive an independent life, besides provides quality care for the babies and little children whose both parents have to work. Although having significant benefits, the area has still major challenges which are investigated in this paper. We provide several state of the art examples together with the design considerations like unobtrusiveness, scalability, energy efficiency, security and also provide a comprehensive analysis of the benefits and challenges of these systems.  相似文献   
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