Research on determining reasonable negative pressure based on the control of the goaf

In order to study the law of spontaneous combustion in goaf under the condition of gas extraction, the method of beam tube monitoring and numerical analysis is adopted to obtain three dimensional distribution of oxygen concentration and contour map under the condition of different negative pressure. Based on the way of regression analysis, reasonable negative pressure are determined. The results show that with the increase of negative pressure, the spontaneous combustion “three-zone” in goaf: the heat dissipation zone and the spontaneous combustion zone become wider and the suffocation zone narrows. At the same time, the trend of spontaneous combustion zone presents to the deep part of the goaf; the amount of gas extraction increases first and then decreases with the increase of negative pressure. Combined with the trend of spontaneous combustion zone and the amount of gas extraction in goaf, and the reasonable negative pressure value is 32kpa and verified.

EKSPLORASI ETNOMATEMATIKA NGADHU DAN BHAGA DALAM KAITANNYA DENGAN PEMBELAJARAN MATEMATIKA PADA MASYARAKAT DESA UBEDOLUMOLO KABUPATEN NGADA

This study aims to determine: (1) to identify the structure of ngadhu and bhaga in Ubedoulumolo Village of Ngada District. (2) Explain the relation of ngadhu and bhaga to mathematics learning in school. The research method used is qualitative with an ethnographic approach. The subjects of this study consisted of three informants (pengu chief, and traditional elders of pengu and gelo tribe). Using observation and interview techniques, supported by documentation, and using qualitative descriptive analysis. The results of the study showed ngadhu and bhaga has related to mathematics, that is the geometry concept. The geometry concept found in ngadhu is: (1) pole ngadhu (made of sebu tree) in the form of a tube; (2) base of ngadhu is composed of a stone in a circle; (3) the roof of ngadhu (material of reeds and palm fibre) in the shape of a cone; (4) bhenga (2 roof support posts) in the form of a beam; (5) mangu (NOK pole) shaped beam; (6) sobhe (head ngadhu made of bamboo) shaped tube; (7) paja (roof truss of bamboo) formed triangle, rectangles, trapezoid. The geometry concept in the bhaga building are: (1) bhaga in the form of the beam; (2) roof (made of reeds) in the shape of a trapezoid and triangular prism; (3) pole shape of beams and tubes; (4) Ube (wall made of plank wood fai) shape of the rectangle; (5) Dawu (arranged boards) with carvings in the form of circles and triangle; (6) Soku bhotha and soku wi’i ( as a roof truss made of bamboo) shape tube rectangle, square and triangle. Geometry forms that exist in the ngadhu and bhaga in the Ubedolumolo Village are lines, angles, triangle, square, rectangle, trapezoid, circle, beam. Tube, cone and triangular prism.

Conceptual implementation stages for Moroccan PGAA/NI instruments: STAGE I & II

The first installation around the tangential beam tube of the Moroccan TRIGA Mark II research reactor comprises combined instruments for Prompt Gamma Neutron Activation Analysis (PGAA) and Neutron Imaging (NI). The implementation of this project is divided over three main stages, namely the installation of the collimator and the primary beam shutter, which is a common section for introduction inside the reactor; the PGAA instruments’ installation; and finally, the installation of the PGNAA/NI combined instruments. The entire design was planned for this project, and detailed information about the first and the second stage is described in this work.