Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area

Based on data from through-hole and logging,we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors.The results show that the damaged positions of drainage wells are mainly located at the thick clay layer in the low alluvium and the lithological interface in the upper section of bedrock in west mining area.The failure depth of casing is 244-670 m and concentrates at about 270-460 m deep.These damaged positions are mainly located in the bending zone according to three zones of rock layers in the vertical section above the roof divided. Generally,the casing begins to deform or damage before the face line about 30-150 m.Special formation structure and rock mass properties are the direct causes of the casing failure,high mining height and fast advancing speed are fundamental reasons for rock mass damage.However,the borehole configuration and spacing to the casing failure are not very clear.

A SIMPLE METHOD TO DETERMINE THE DAYLIGHT FACTOR FROM THE VERTICAL DAYLIGHT FACTOR IN DIFFERENT STREET CANYON GEOMETRY

This paper investigates the main characteristics of daylight on any window in a street canyon.The sky component and the light reflected from the surroundings are described to determine the vertical daylight factor(VDF).Several street canyon types are characterized taking into account their different height/width and any level of the window is analysed.A simple calculation method uses trigonometric equations based on the sky and the geometry of the canyon.The results were previ-ously evaluated considering different daylight procedures obtained by other studies.This study reveals that the reflectance within an urban canyon plays an important role in the amount of daylight onto any window with more relevance in a deep canyon and low sky view.The graphical presentation that result from this investiga-tion can rapidly assist building and urban designers in an early stage design where assumptions and the lay out of the main design take place.

A new fractal algorithm to model discrete sequences

Employing the properties of the affine mappings, a very novel fractal model scheme based on the iterative function system is proposed. We obtain the vertical scaling factors by a set of the middle points in each affine transform, solving the difficulty in determining the vertical scaling factors, one of the most difficult challenges faced by the fractal interpolation. The proposed method is carried out by interpolating the known attractor and the real discrete sequences from seismic data. The results show that a great accuracy in reconstruction of the known attractor and seismic profile is found, leading to a significant improvement over other fractal interpolation schemes.

Local linear scale factors in map projections in the direction of coordinate axes

This paper explains that the terms“horizontal and vertical scales”are not appropriate in map projections theory.Instead,the authors suggest using the term“scales in the direction of coordinate axes.”Since it is not possible to read a local linear scale factor in the direction of a coordinate axis immediately from the definition of a local linear scale factor,this paper considers the derivation of new formulae that enable local linear scale factors in the direction of coordinate x and y axes to be calculated.The formula for computing the local linear scale factor in any direction defined by dx and dy is also derived.Furthermore,the position and magnitude of the extreme values of the local linear scale factor are considered and new formulas derived.

DAYLIGHT IN A CISTERCIAN HERITAGE CHURCH IN LISBON,FROM RURAL TO URBAN CONTEXT

Light levels in the churches of the Cistercian Order are mostly related to the fulfilment of liturgical needs.The compound building of Bernardas’Convent includes a church at the utmost southern corner that dates back to the 17th century.It only has one façade facing due southeast.This paper analyses the relationship between daylight conditions within the building before and after the urbanisation of the surrounding area;taking into account the relationship between the church,its main activities,and solar trajectory.A comparative analysis of the relationship between the actual surrounding context and the initial period after it was built(open field)is given.The highest reflectance of the street canyon has augmented the levels of available daylight.