No abstract

The use of flipped‐classroom methodology (FC) has increased recently, however, there is a lack of quantitative data on students’ performance. A FC has been applied into a group (80 students) of an obligatory subject of the 2nd course in an Energetic Engineering Bachelor. A second group has been taught with the traditional methodology (72 students) to compare the results. The FC requires students to obtain background knowledge prior to a face‐to face class meeting, and reserves in‐class time for applying knowledge to solve problems. This is the opposite of the traditional lecture‐based classroom, in which students passively attend didactic lectures from the instructor, then study the content and complete assignments after class. The main objectives of this research were to measure the impact of learning (with special attention to really active students), reduce absenteeism, increase exam attendance, and analyze how participating students view their experience with this methodology. The results show that the flipped‐classroom model has a direct impact on student learning (or grades), especially in students with a high degree of involvement (with grades about 1.5 points higher). In addition, the grades standard deviation values were lower (in about one point), ensuring a better general students level. The students are a little reluctant to this new methodology, but thanks to it, they tend to work more (12% of the students work more hours per week), to attend more to class (at least 10% more), and to attend in a higher ratio to exams (around 20%).

Turning waste into a resource is a way to increase resource use efficiency and close the material loop of a circular economy. Gypsum plasterboard is well suited for this, because the raw material calcium sulphate dihydrate (CaSO 4 •2H 2 O) can repeatedly change its properties through a reversible hydration reaction. The waste hierarchy is applied when plasterboard is recycled instead of landfilled, which contributes to the European 2020 target of 70% recovery of construction and demolition (C&D) waste, as defined in the Directive 2008/98/EC on Waste. This paper evaluates the energy and climate impacts of different levels of plasterboard recycling. First we formulate a life cycle model of gypsum mass flows in the European Union (EU-27) in the reference year 2013. This model constitutes the basis of the quantitative scenario analysis. Secondly we assess the material flows, energy use and greenhouse gas (GHG) emissions in different recycling scenarios. We compare the current situation (-2013 base case‖) to two scenarios: a worst case scenario of 0% recycled gypsum (-Zero recycling case‖), and a best case scenario of zero gypsum waste sent to landfill, corresponding to 18.7% recycled gypsum in new plasterboard (-High recycling case‖). We find no significant variation between scenarios in terms of life cycle energy use, as lower impacts from gypsum mining, transport of natural gypsum and final disposal in the best case scenario are balanced by the energy for the transport of plasterboard waste and recycled gypsum and for material pre-processing during manufacturing. In contrast, life cycle GHG emissions are lower as recycling increases, largely driven by the degradation of plasterboard lining paper in landfills.

A purely algebraic method which uses the matrix Routh algor-ithm and its reverse process of the algorithm is presented to decompose a mat.ri x transfer function into a pair of right co-prime polynomial matrices or left co-pr-ime polynomial matrices. The poles and transmission zeros of the matrix transfer function arc determined from a. pair of relatively prime polynomial matrices. Also, tho common divisor of two matrix polynomials CRn be obtained by using the matrix Routh algorithm and the matrix Routh array.

Blasting performance is influenced by mechanical and structural properties of the rock, on one side, and blast design parameters on the other. This paper describes a new methodology to assess rock mass quality from drill-monitoring data to guide blasting in open pit operations. Principal component analysis has been used to combine measurement while drilling (MWD) information from two drill rigs; corrections of the MWD parameters to minimize external influences other than the rock mass have been applied. First, a Structural factor has been developed to classify the rock condition in three classes (massive, fractured and heavily fractured). From it, a structural block model has been developed to simplify the recognition of rock classes. Video recording of the inner wall of 256 blastholes has been used to calibrate the results obtained. Secondly, a combined strength-grade factor has been obtained based on the analysis of the rock type description and strength properties from geology reports, assaying of drilling chips (ore/waste identification) and 3D unmanned aerial vehicle reconstructions of the post-blast bench face. Data from 302 blastholes, comprised of 26 blasts, have been used for this analysis. From the results, four categories have been identified: soft-waste, hard-waste, transition zone and hard-ore. The model determines zones of soft and hard waste rock (schisted sandstone and limestone, respectively), and hard ore zones (siderite rock type). Finally, the structural block model has been combined with the strength-grade factor in an overall rock factor. This factor, exclusively obtained from drill monitoring data, can provide an automatic assessment of rock structure, strength, and waste/ore identification.