Methane has been controlled in collieries in the past only for safety and statutory compliance reasons; however concerns over greenhouse gas emissions mean that this is now changing. About 65% of greenhouse emissions associated with underground coal mining come from ventilation air methane (VAM). The machinery to mitigate these fugitive emissions once the VAM exits the mine fans is expensive, has safety concerns and is not widely used at present. Consider these factors; more collieries are mining lower seams, methane content increases with depth, VAM mitigation plants are not widely used, most mine emissions are VAM, and widespread concern over greenhouse gases mean that it is desirable to lower VAM emissions now. One solution would be a method to prevent more methane from entering the mine airstream and becoming VAM in the first place. Recently, in a colliery in the Hunter Valley, this mitigation method underwent a 12-month trial, and involved six different measures. Measurements were taken to assess the emissions mitigation which was achieved, and the cost of the works; all the results are detailed herein. A reduction in fugitive emissions of 80,307 t/CO2-e below that which was projected for the next 12-month period was quantified, at an average cost of A$1.28c t/CO2-e. The mitigation measure outlined here represent a first attempt to the author’s knowledge, in an operating mine, to lower a collieries’ environmental footprint by preventing methane from entering the mine airstream and becoming VAM gas by the deliberate use of mitigation measures.
This paper presents a study on using the steady-state three-dimensional heat transfer software HEAT3 for evaluating the heat flow of heat transfer through different elements of the building envelope in order to establish the linear thermal transmittance of the linear thermal bridge. The linear thermal transmittance is obtained according to the one-dimensional steady-state heat transfer calculation formula for the plane walls using the heat flow values obtained through the method specified above. The results presented in this paper are part of a wider study on evaluating the heat transfer through building’s envelope elements by evaluating as accurate as possible the thermal bridges effect of the most common building structures. As a case study, it was considered the steady-state heat transfer through an opaque outer wall of a building considering the thermal bridges for the following elements: outer walls intersection, inner and outer wall intersection and outer wall with intermediate floor intersection.
The emergence of led luminaries in street lighting has modified traditional design guidelines. The highest led energy efficiency allows keeping suitable lighting levels with less installed power. Thus, the present design line of a street lighting installation is closely related to the technological change: kind of led to be used, suitable lens, efficacy relationship regarding high pressure sodium, light colour temperature, spectrum. The “impact” associated to with led conversion relegates main aspects of street designs: effect of road reflective properties and installation depreciation. The wear produced by traffic, as well as the environmental conditions gradually modifies the road reflection matrix. In a street lighting installation, this change alters the luminance arrangement on the road together with the perception conditions. This phenomenon is a determining factor within the global concept of depreciation affecting lighting systems in general and also street lighting installations designed by the Luminance Technique. In the present work changes, due to use, in the shape of street reflection matrices of Argentinean highways are analyzed. The analyzed r-tables were obtained through “in-situ” measurements, with road reflectometer. A first group corresponds to the initial conditions of macro textured roads which were measured in the period 2001/2003. The second studied set contains r-tables of the same type, and according to its use the surfaces can be considered in steady state, assessed between 2005 and 2009. The study provides information about the shape of matrixes and its alteration, specularity and scale factor, relating such parameters with the possible effects on the resulting lighting.
During last years the need of knowing the forest in its various aspects, quantitative and qualitative, has enabled the appearance of a new technique forestry geomatics. Named as “the science of future” this technique integrates multiple technologies such as Remote Sensing, Airborne Photogrammetry, LIDAR, Geographic Information System (GIS), Global Positioning Systems (GPS) or classical geodetic technology for data acquisition, data processing, data analysis and data management. The purpose is to provide specific information regarding the evaluation natural forestry resources. In this paper will be presented the utilization of terrestrial 3D laser scanner and GIS technologies in forestry inventory.
In this paper, four specimens of steel beam to column joints with different configuration of bolted angle connections are experimentally tested. The specimens are double sided beam to column connections and are tested under bending loading conditions in order to investigate elastic and inelastic connection behaviour. The semi-rigid beam-to-column connections were subjected to monotonous static loading. The bolted beam-to-column connections are composed from top and seat angle connections with and without web angles as well as with stiffened top and seat angle cleats. The intent of the experimental investigations is to highlight the ability of the connections to maintain strength and to provide rotational capacity. The experimental results are evaluated with the measured force displacement data, from which the characteristic moment-rotation curves were established. The experimental results indicate the primary failure modes include member deformation. The moment-rotation relationship of the tested joints exhibits a significant inelastic nonlinear response. The paper concludes with the comparison of the tested joints in terms of strength and stiffness, highlighting the advantages and weaknesses of the studied joint typologies.
The article presents aspects related to the calculation of heat loss through the pipes of the interior central heating system. The purpose of the article is to detail the local heat losses in case of central heating systems. Based on the conclusions of the article, we propose the modification of the calculation methodology related to the building energy audit.
From the entire globe surface which is over 13.5 billion ha, the agricultural area represents more than one quarter (means 3.4 billion ha). The cultivated areas cover approximately 1.5 billion ha, which means 8% of the total lands, to each inhabitant of the planet assuming the 0.25 ha. The most agricultural space is located in the temperate zone (about 2 billion ha), which represents 55% of agricultural space world and also here lies mostly in the sown area of the planet (830 thousand ha, 59%).
An issue more and more important in construction science represents the rehabilitation of structures placed on difficult soils. This paper presents the behaviour analysis of an existing structure and summarizes several consolidation solutions at both levels of a severely damaged construction placed on a shrinking and swelling soil, located in Arad County - Romania, situated on 55 Revolutiei Avenue. These types of soils are known in specialty literature as shrinking fields, expansive or active soils, having the property to modify sensitively their entire volume when there are variations of moisture, being spread on a large scale in Romania. After the assessment of seismic safety for a section of the damaged structure, which is characterized by a high risk of collapse from seismic action, reason for which it has been proposed to immediate by consolidate the damaged construction.
Malta is a representative model for recording and preserving archaeological remains and historical monuments. Being a historically and culturally rich location, it requires creating, maintaining and updating a database in order to keep a record of the state of degradation or the actions to restore historical monuments. One way to preserve the image and shape of a historical monument is by creating a three-dimensional model. The advantage of such a model is its visualization and keeping in a form close to the real shape of a monument in a particular moment in time. It can thus highlight the levels of wear and degradation, the eventually necessary rehabilitation works or simply reproduce the impressions that the building would actually leave on a visitor.
The recycling issues related to the construction and demolition (C&D) wastes in the sustainable development and the circular economy context represent a continuous challenge for researchers. This paper reveals the possibility to recycle the hardened mortar recovered from C&D wastes. Thus, the recovered hardened mortar with grains size less than 16 mm was used in the concrete structure. The compression resistance of the final concrete was determined using a Heckert 3000 KN testing machine and the results showed a better compressive strength for the samples with C&D waste content than the standard sample of about 1.19 times. This is a good premise for improving the researches related to C&D waste usage in concrete production.