Penetration in a graded filter

An experimental laboratory study conducted to examine clogging within and penetration of fines into a single layer graded filter. Hydraulic gradient, filter gradation and flow direction were varied. Forty one tests gave over six hundred individual penetration depths. The magnitude of penetration in filters with considerable variation in gradation patterns correlated with an average hydraulic radius based on the volume of voids and an approximated total surface area. It has been shown than an increased thickness of poorly graded filter will stop penetration such as that caused by seepage erosion. A relationship between hydraulic radius, penetration depth and probability of penetration has been presented --Abstract (1), page v.|| An experimental study to examine the clogging within and penetration of fines into a single layer graded filter has been made and a relationship between hydraulic radius, penetration depth and probability of penetration developed --Abstract (2), page vi

Songbird organotypic culture as an in vitro model for interrogating sparse sequencing networks

Sparse sequences of neuronal activity are fundamental features of neural circuit computation; however, the underlying homeostatic mechanisms remain poorly understood. To approach these questions, we have developed a method for cellular-resolution imaging in organotypic cultures of the adult zebra finch brain, including portions of the intact song circuit. These in vitro networks can survive for weeks, and display mature neuron morphologies. Neurons within the organotypic slices exhibit a diversity of spontaneous and pharmacologically induced activity that can be easily monitored using the genetically encoded calcium indicator GCaMP6. In this study, we primarily focus on the classic song sequence generator HVC and the surrounding areas. We describe proof of concept experiments including physiological, optical, and pharmacological manipulation of these exposed networks. This method may allow the cellular rules underlying sparse, stereotyped neural sequencing to be examined with new degrees of experimental control