Mitigating Harmful Effects of Climate Warming on Ceiling Paintings by Ceiling Insulation: An Evaluation Using Timed IR Imaging and Numeric Modelling

Due to climate change, ceiling paintings in many historic buildings are subjected to increasingly high short-term temperature change, resulting in high thermal tension caused by the construction assembly. This article focuses on the combined use of timed IR imaging and numeric modelling to evaluate insulation measures on the upper side of a ceiling to reduce thermal tensions in the painting layers, overheating in summer as well as cooling down in winter. As a model room, the southern splendour stair hall in the Burgtheater Vienna was chosen. Famous ceiling paintings created from 1886 to 1888 by Gustav Klimt and his brother Ernst Klimt can be found on this ceiling. The results show that timed IR imaging is an adequate tool to study the transient thermal behaviour of ceiling paintings which are not accessible to standard sensor measurements. Moreover, it could be shown that the presented measurement technique is well suited to validate a numeric model. The latter was applied to evaluate the potential insulation on the top of the ceiling. It was shown that cooling loads and energy loss in the room underneath can be reduced and most importantly the thermal stress in painting layers is reduced. The findings are relevant as, due to global warming, the current situation in many buildings is worsening. Considering the great intangible cultural value of many ceiling paintings, the application of the presented evaluation strategy for building physical boundaries on a ceiling with paintings seems to be appropriate.

Experimental Verification of the Elastic Response in a Numeric Model of a Composite Propeller Blade with Bend Twist Deformation

Adaptive composite propeller blades showing bend twist behaviour have received increasing interest from hydrodynamic and structural engineers. When exposed to periodic loading conditions, such propellers can be designed to have higher energy efficiency and emit less noise and vibration than conventional propellers. This work describes a method to produce an adaptive composite propeller blade and how a point load experiment can verify the predicted elastic response in the blade. A 600 mm-long hollow full-size blade was built and statically tested in the laboratory. Finite element modelling predicted a pitch angle change under operational load variable loads of 0.55°, a geometric change that notably compensates for the load cases. In the laboratory experiment, the blade was loaded at two points with increasing magnitude. The elastic response was measured with digital image correlation and strain gauges. Model predictions and experimental measurements showed the same deformation patterns, and the twist angle agreed within 0.01 degrees, demonstrating that such propellers can be successfully built and modelled by finite element analysis.

Dynamics of part motion on a linear vibratory feeder

The motion of a part on a curved surface mounted upon a linear vibratory feeder is of great importance in mass production. In this article, the conveying surface or track is modelled by a bilinear surface inclined to all axes with the curvature varying throughout the surface. An experimental test rig is fabricated to study the part motion on the feeder surface. Dynamics of the part on the surface is derived and the path traced by the part is obtained numerically. The numeric model closely correlates with experimental results. Based on the control parameters two distinct regimes—slide and hop—are presented, highlighting their relation to frequency and amplitude of vibration of the feeder.

A Machine Learning Perspective on Causes of Suicides and identification of Vulnerable Categories using Multiple Algorithms

BackgroundSuicides represent a social tragedy with long term impact for the family. Given the growing incidence of suicides, a better understanding of factors causing it and addressing them has emerged as a social imperative.Material and MethodsThis study analyzed suicide data for three decades (1987-2016) and was carried out in two phases. Machine Learning Models run after pre-processing the suicide data included Neural network, Regression, Random Forest, XG Boost Tree, CHAID, Generalized Linear, Random Trees, Tree-AS and Auto Numeric Model.Results and ConclusionAnalysis of findings suggested that the key predictors for suicide are Age, Gender, and Country. In the second phase, data from happiness reports were merged with suicide data to check if Country-specific factors impact the list or order of key predictors. While the key predictors remain the same, Country-specific factors like Generosity, Health and Trust impact the suicide rate in the Country.

River Model Calibration Based on Design of Experiments Theory. A Case Study: Meta River, Colombia

Numerical models are important tools for analyzing and solving water resources problems; however, a model’s reliability heavily depends on its calibration. This paper presents a method based on Design of Experiments theory for calibrating numerical models of rivers by considering the interaction between different calibration parameters, identifying the most sensitive parameters and finding a value or a range of values for which the calibration parameters produces an adequate performance of the model in terms of accuracy. The method consists of a systematic process for assessing the qualitative and quantitative performance of a hydromorphological numeric model. A 75 km reach of the Meta River, in Colombia, was used as case study for validating the method. The modeling was conducted by using the software package MIKE-21C, a two-dimensional flow model. The calibration is assessed by means of an Overall Weighted Indicator, based on the coefficient of determination of the calibration parameters and within a range from 0 to 1. For the case study, the most significant calibration parameters were the sediment transport equation, the riverbed load factor and the suspended load factor. The optimal calibration produced an Overall Weighted Indicator equal to 0.857. The method can be applied to any type of morphological models.

Evaluación del Recurso Hidrocinético en las Partes Bajas de la Región Hidrológica 29Ba de la Cuenca del Río Coatzacoalcos

Hydrokinetic energy is induced by the velocity in the natural causes of rivers and is used for electric generation. Human settlements have always been established on the margins of the rivers, therefore it is very useful to evaluate the hydrokinetic resource in the places where there are populations on the banks of the rivers, mainly in places where there is no service available electric power. In this work, the hydrokinetic potential along the river in different sites of the flat parts of the hydrological region 29Ba is determined. The flows in the rivers are calculated taking into account the use of soil, the precipitation of different meteorological stations, which are processed in a Geographic Information System (GIS). The calculated flows are compared with the observed data of the hydrometric station Las Perlas of CONAGUA. The velocities along the river are calculated with the numeric model Hec-Ras, later the minimum, maximum and average monthly hydrokinetic potential is estimated with some turbine models designed for this purpose.

Small scale gas turbine combustor sizing

Presented article is focused on initial design of small scale combustors for micro scale jest engines. In comparison to the full size equivalent, small combustor are design and manufactured in experimental way. To try building universal numeric model for micro size design is important to acquire as many data as possible to identify boundary conditions for a model. Major advantage of analyzing different design is possibility to quick building prototype design without investigating complex process of combustion.

Identification of numerical model parameters of tunnel lining in non-cohesive soil

The paper discusses identification of numeric model parameters of tunnel lining in a soil medium according to the discrete element method. An author’s program based on the discrete element method was used. Laboratory tests were conducted to determine the computer model parameters defining the lining and the soil medium. The numerical model was calibrated by comparing the lining deformations occurring in the laboratory test and in the numeric simulation. Tunnel lining displacement during laboratory tests was determined using digital photography. Keywords: civil engineering, discrete element method, cylindrical tunnel lining