Two-dimensional (2D) hopper flow of disks has been extensively studied. Here, we investigate hopper flow of ellipses with aspect ratio α = 2, and we contrast that behavior to the flow of disks. We use a quasi-2D hopper containing photoelastic particles to obtain stress/force information. We simultaneously measure the particle motion and stress. We determine several properties, including dischar...

An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%), Endosulfan (0.5%), and Cypermethrin (0.4%), and natural Neem oil (3%) with three replications of each. All the treatments were significantly effective i...

Three experiments were conducted to test an interpretation of the response-rate-reducing effects of unsignaled nonresetting delays to reinforcement in pigeons. According to this interpretation, rates of key pecking decrease under these conditions because key pecks alternate with hopper-observing behavior. In Experiment 1, 4 pigeons pecked a food key that raised the hopper provided that pecks on...

This study experimentally examines the flow of glass spheres in a wedgeshaped hopper that is vibrated horizontally. When the hopper is discharged without vibration, discharge occurs as a hnnel flow, with the material exiting the central region of the hopper and stagnant material along the sides. With vibration, the discharge of the material occurs in reverse, with the material along the sides e...

Prosopis africana is an under utilized tree crop with immense medicinal and industrial values. Manual threshing of the pods to extract the seeds is uneconomical, time consuming, associated with drudgery and low output capacity. A motorized Prosopis africana pod thresher was designed, fabricated and assessed for performance. The main components of the thresher include hopper, threshing unit, cle...

Pigeons rapidly acquire a key-pecking response when 8-sec illuminations of a response key precede each presentation of grain (Brown and Jenkins, 1968). Bilbrey and Winokur (1973) and Winokur and Boe (1975) have reported that such autoshaped responding does not occur when grain presentation is preceded by a tone, either presented from a speaker separate from the response key or from a speaker be...

Idioscopus clypealis (Lethierry) is commonly known as mango leaf hopper. The hopper reduces mongo production by causing non setting of flower and dropping of immature fruits. The first appearance of hoppers (0.12 and 0.16) on the branches of mango trees was recorded in February which is correlated with increase in maximum (23.89 degrees C and 24.29 degrees C) and minimum temperature (11.46 degr...