Fine particles tend to accumulate in recirculating aquacultural facilities, which can lead to serious fish health problems. The literature indicated that in many particle systems, the particle size distribution may be accurately represented by a two-parameter, hyperbolic power-law function, dN/dl=Al−β.
The purpose of this paper is to investigate whether this observation holds for aquacultural facilities. Particle size distribution data from four research establishments were examined, using 14 data sets, comprising 11 aquacultural systems, and covering three species of salmonids and one of striped bass. In the data examined, the exponent, β, varied from 2.9 to 4.6, with one sample reaching as high as 6.3. Correlation coefficients varied from 0.998 to 0.975. Larger exponents, indicating a greater number of fine particles, appear to dominate recirculating aquaculture systems.
The results strongly suggest that a hyperbolic distribution is valid for aquaculture systems. The usefulness in this technique is that once a worker has established the exponent from the distribution of particle sizes at any given point in his facility, an estimate of particulate contributions by size to the total particle number, surface area and volume/mass concentration can be obtained. 相似文献
为降低传统环模成型机的能耗,设计了一种齿辊式环模成型机,并对该成型机的运动干涉、最大攫取角进行了理论分析。结果表明按照设计尺寸运动并不干涉,最大攫取角大于普通环模;在该样机上以含水率8%~20%四倍体刺槐颗粒为原料进行了成型对比试验,结果表明:不同含水率下的平均比能耗为56.82 k W·h/t,成型密度为1.085 g/cm3,比同样结构的普通环模产量提高了3.36%~6.25%,能耗降低5.77%,密度提高3.33%,同时发现在含水率16%、转速200 r/min时比能耗最低,为50.3 k W·h/t。 相似文献