This paper studies the unstable mechanisms of the mechanical system that is composed of the stiff hosts (roof and floor) and the coal pillar using catastrophe theory. It is assumed that the roof is an elastic beam and the coal pillar is a strain-softening medium which can be described by the Weibull s distribution theory of strength. It is found that the instability leading to coal bump depends...

In an urban area, the roof is the only available surface that can be utilized for installing solar photovoltaics (PV), and the active surface area depends on the type of roof. Shadows on a solar panel can be caused by nearby tall buildings, construction materials such as water tanks, or the roof configuration itself. The azimuth angle of the sun varies, based on the season and the time of day. ...

OBJECTIVES To determine the range of normal radiographic joint space width (JSW) values and the shape of the normal hip, and the influence of age, sex, dysplasia, coxa profunda, and acetabular roof curve abnormalities on these values. METHODS On routine conventional pelvic radiographs taken in the supine position in patients with no history of hip or lumbar pain, JSW was measured at three poi...

The backfilling mining method can effectively solve the environmental and safety problems caused by mining. It is key technology to realize green Scientific development has accelerated pace of research on rational utilization mine solid waste improved level technology. history introduced in present paper, it determined that roof-contacting mine-solid-waste This paper introduces three calculatio...

The roof plate is a signalling centre positioned at the dorsal midline of the central nervous system and generates dorsalising morphogenic signals along the length of the neuraxis. Within cranial ventricles, the roof plate gives rise to choroid plexus, which regulates the internal environment of the developing and adult brain and spinal cord via the secretion of cerebrospinal fluid. Using the f...

By means of airborne multiple camera imaging system, we can acquire vertical and oblique aerial images (VAI and OAI) at the same time. In addition to the reduction of data cost, the OAI can also strengthen the imaging geometry during aerial triangulation and be applied on automatic façade texture mapping. With the development of image matching technique, instead of airborne laser scanning (ALS)...

A novel Markov random field (MRF) model is proposed for roof-edge (as well as step-edge) preserving image smoothing. Image surfaces containing roof-edges are represented by piecewise continuous polynomial functions governed by a few parameters. Piecewise smoothness constraint is imposed on these parameters rather than on the surface heights as is in traditional models for step-edges. In this wa...

The self-consistent integral equation for the field distribution of the resonant modes in a resonator with a tilted retroreflecting roof mirror is solved. The field distribution in the direction of the roof can be described in terms of Hermite-Gaussian functions. The beam matrix for a retroreflecting roof is found, and a new type of resonator which does not need precise alignment is proposed.