Radial gas distribution in the blast furnace top

Blast furnace process control heavily depends on good control of burden and gas distribution. For many blast furnaces this control relies on measurements with fixed above-burden probes. Therefore, an accurate knowledge of the gas flow between stockline and above-burden probes is of paramount importance. Measurements in the blast furnace top and calculations with a mathematical model are used to shed more light on the gas flow in the blast furnace top. It turned out that complex gas flows cause several differences between data at stockline level and at above-burden probe level. There is an acceleration of gas in the furnace centre due to the much higher temperature there. Gas from the colder intermediate region is therefore attracted towards the centre. There is hardly any influence of the inclination of the stockline. It is advisable to make the distance between stockline and above-burden probes as small as possible or to use some form of in-burden measurement.     

Health status and satisfaction with health care: Results from the medical outcomes study.

Relations between self-assessed health status and satisfaction with health care were examined using 2 waves of data obtained from participants in the Medical Outcomes Study. Using a multisample covariance modeling framework, separate models were examined for patients with significant symptoms of depression (n?=?417 ) and patients with chronic physical health conditions (n?=?535 ). The pattern of findings was essentially identical for both patient subgroups. General satisfaction with care was cross-sectionally associated with mental?but not physical--health status. In addition, significant cross-lagged effects were found linking baseline satisfaction with care to subsequent mental health and baseline mental health to subsequent satisfaction with care. By contrast, no crosslagged directional effects linking satisfaction with care and physical health status were identified. Finally, no evidence was found that satisfaction with specific aspects of health care contributed independently to either mental or physical health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

高性能射频调制器促成多载波通信发送器设计

引言 现有的蜂窝基站大多采用超外差结构发送或接收射频信号.这种结构需要两次变频或更多的上、下变频级、中间滤波和模拟信号处理.图1的上半部分给出了一个两级转换蜂窝基站的典型超外差发送框图,很多此类发送器已经被应用在单载波系统.因为多载波发送器是从单载波发送器复制得到的,所以引入了更多的系统硬件.为了努力降低发送器的成本,许多系统设计者开始转向多载波发送器和简单的直接变换射频结构.     

Noise-enhanced information transmission in rat SA1 cutaneous mechanoreceptors via aperiodic stochastic resonance

1. Aperiodic stochastic resonance (ASR) is a phenomenon wherein the response of a nonlinear system to a weak aperiodic input signal is optimized by the presence of a particular, nonzero level of noise. Our objective was to demonstrate ASR experimentally in mammalian cutaneous mechanoreceptors. 2. Experiments were performed on rat slowly adapting type 1 (SA1) afferents. Each neuron was subjected to a perithreshold aperiodic stimulus plus noise. The variance of the noise was varied between trials. The coherence between the aperiodic input stimulus and the response of each SA1 afferent was computed. 3. Of the 12 neurons tested, 11 showed clear ASR behavior: as input noise variance was increased, the stimulus-response coherence rapidly increased to a peak and then slowly decreased. These findings were in contrast with those for the average firing rate, which increased monotonically as a function of input noise variance. 4. This work shows that noise can serve to enhance the response of a sensory neuron to a perithreshold aperiodic input signal. These results suggest a possible functional role for input noise in sensory systems. These findings also indicate that it may be possible to introduce noise artificially into sensory neurons to improve their abilities to detect arbitrary weak signals.     

Emissions from large-scale medium-speed diesel engines: 3. Influence of direct water injection and common rail

The influence of direct water injection (DWI) on emissions from a multivariable large-scale (6–18 cyl, ~ 1 MW/cyl) diesel engine is reported, using a combined injection valve and nozzle that allows for injection of water and fuel oil into the cylinder. This method allows for injecting a relatively large amount of water without derating the engine power and NO_x emissions can be more than halved by DWI. Indeed DWI decreases combustion temperatures and NO_x emissions, but it gives somewhat increased (yet not problematic) emissions of CO, HC, soot (smoke) and particulate matter (PM), depending on the water injection timing and degree of incomplete combustion.