Experimental and FE Study on Impact Strength of Toughened Glass–Retrospective Approach

Due to the high cost of experiments commonly performed to verify the resistance of glass elements to impact loads, numerical models are used as an alternative to physical testing. In these, accurate material parameters are crucial for a realistic prediction of the behaviour of glass panels subjected to impact loads. This applies in particular to the glass’s strength, which is strictly dependent on the strain rate. The article reports the results of an extensive experimental campaign, in which 185 simply supported toughened glass samples were subjected to hard-body impacts. The study covers a wide range of glass thicknesses (from 5 to 15 mm), and it aims to determine a critical drop height causing fracture of the glass. Moreover, a 3D numerical model of the experimental set-up was developed to reproduce the experiments numerically and retrospectively to determine the peak stress in glass that developed during the impact. Based on the results of numerical simulations, a load duration factor of 1.40 for toughened glass for impact loads is proposed. In addition, the paper includes a case study to demonstrate the use of the modelling methodology and results of the work on a practical example of an internal glass partition wall.

Electrical Efficiency Increase in CPVT Collectors by Spectral Splitting

Concentrating photovoltaic-thermal (CPVT) collectors have to face the challenge of contrary temperature requirements in the single receiver parts. The PV cells require low temperatures to achieve high efficiency, whereas the thermal part should generate high temperatures for providing industrial heat. The approach of “Spectral Splitting” can offer a solution for compact CPVT receivers; however, a clear quantification of the expected conversion efficiency is difficult. Therefore, this paper describes a modelling methodology for obtaining electrical and thermal performance parameters for a Spectral Splitting configuration using semiconductor-doped glass combined with appropriate heat transfer fluid. The PV technologies c-Si, CIGS and CdTe are considered. The presented model yields distinct results for maximising the electrical efficiency, calculates the reduction in waste heat dissipation within the cells and assesses the impacts of concentration factor and cell temperature. An optimised configuration could be found with CIGS cells, impinged by a selected wavelength spectrum between 868 nm and 1100 nm, where the theoretical efficiency reaches 42.9%. The waste heat dissipation within the cells is reduced by 84.9%, compared to a full-spectrum operation. The depicted CPVT receiver design using bendable thin-film PV cells will be realised as a prototype in a subsequent project phase.

Hydrodynamic modelling of historical flood event using one dimensional HEC-RAS in Kelantan basin, Malaysia

Hydraulic simulation models are critical tools for analysing the hydraulic properties of a river’s system flow. The work focuses on the simulation of a river flow in a Kelantan basin using the one-dimensional (1D) Hydrologic Engineering Center - River Analysis System (HECRAS). In the present study, cross-sections from survey data were utilised into the RAS Mapper provided in HEC-RAS 5.0 to simulate the river flow in the region. This study highlights the modelling methodology with a focus on data collection and its importance during the calibration and validation process. The model was used to discover the expected peak flood levels based on historical flood events. Simulated flows were utilised to examine the potential of the model during the model development procedure. The simulation outcomes reveal that the simulated flows are in excellent agreement during the model development as the obtained R2 value was between 0.95 to 1.0 during both model calibration and validation. This demonstrates the applicability of the HEC-RAS 1D model in simulating precise river flow, especially for flood events.

Determining Factors for the Creation of Innovation-based Ventures

This research aims to create a model that provides a more complete view of the behavior of entrepreneurs, to investigate the influence of Social Capital, Entrepreneurial Self-Efficacy and Per-son-Entrepreneurship Fit in the transition of nascent entrepreneurs towards the venture creation. For the development of this research, a sample of 500 entrepreneurs located in Colombia who are in the process of creating a company was taken. The research methodology is hypothetical-deductive with a cross-sectional multiple causal correlation design with explanatory scope and is divided into three stages: First, an exploratory analysis of the data relating to the study variables is carried out. Second, a Principal Component Analysis is carried out. Finally, the third stage is the modelling using the Partial Least Squares - Path Modelling methodology. Among the most relevant findings, it is found that Social Capital is significant in explaining Person-Entrepreneurship Fit. In turn, Social Capital and Person-Entrepreneurship Fit are significant in explaining Entrepreneurial Self-Efficacy. Finally, the construct of Venture Creation is only significantly explained by Per-son-Entrepreneurship Fit. Consequently, it can be concluded that the influence of social and psychological variables within the business cycle are significant, and models and strategies must consider these elements in order to design tools that support the optimal development of start-ups within the business cycle, so that they consolidate as stable ventures.

Ranking of barriers for the internet of things implementation in the E-learning platform

Learning through the Web or training via e-learning is rising exponentially and is gradually preferred by conventional ways of education and training. This massive change is directly related to digital computer technological advancement. The transformation driven by innovation in computer technology has enhanced the reach of e-learning and education, making the process of sharing knowledge easy, clear, and efficient. The E-learning system relies on various success factors from several viewpoints, such as framework, organisational alignment, instructor, and student support. This paper aims to identify the critical barriers to the Internet of Thing implementation in e-learning and to establish a relational relationship between identified barriers using the Interpretive Structural Modelling approach. This paper has established some primary barriers that are useful for Internet of Things implementation in E-learning by research scholars and industrial practitioners. For the study of the driving force and dependency power of the E-learning barrier, Interpretive Structural Modelling methodology was used to classify interrelationships between barriers for improved understanding and relationships between these barriers, and Management Cross Impact Multiplications were conducted to estimate the magnitude of these relationships. Applied to classification analysis, which is used for analysing the driving power and dependence power of E-learning barriers.

Modeling time series by aggregating multiple fuzzy cognitive maps

Background The real time series is affected by various combinations of influences, consequently, it has a variety of variation modality. It is hard to reflect the variation characteristic of the time series accurately when simulating time series only by a single model. Most of the existing methods focused on numerical prediction of time series. Also, the forecast uncertainty of time series is resolved by the interval prediction. However, few researches focus on making the model interpretable and easily comprehended by humans. Methods To overcome this limitation, a new prediction modelling methodology based on fuzzy cognitive maps is proposed. The bootstrap method is adopted to select multiple sub-sequences at first. As a result, the variation modality are contained in these sub-sequences. Then, the fuzzy cognitive maps are constructed in terms of these sub-sequences, respectively. Furthermore, these fuzzy cognitive maps models are merged by means of granular computing. The established model not only performs well in numerical and interval predictions but also has better interpretability. Results Experimental studies involving both synthetic and real-life datasets demonstrate the usefulness and satisfactory efficiency of the proposed approach.

Assessing the Impact of Virtual Standby Systems in Failure Propagation for Complex Wastewater Treatment Processes

This article proposes an original probabilistic modelling methodology named Virtual Standby (VSB), which enables a practical simulation, analysis, and evaluation of the impact on availability and reliability achieved by potential buffering policies on the performance of complex production systems. Virtual Standby (VSB) corresponds to a design and operational characteristic where some machines under a failure scenario are capable to provide for a limited time, continuity to the subsystems downstream before suffering delay which is currently not considered when assessing availability. This feature plays a relevant role on the propagation of the effect of a failure; indeed, it could prevent the propagation by guaranteeing the isolation time needed to recover from its failure, controlling and reducing the production losses downstream. A case study of the preliminary treatment process of a wastewater treatment facility (WWTF) is developed bearing in mind the systemic behaviour in the event of a failure and the specific features of each equipment. VSB is a big advantage for the representation of this complex processes because, among other things, it considers the impact of buffering policies on the perceived availability of the system. This model allows determining different production levels, with a better and easier fitting of the reliability, availability, and production forecast of the process. Finally, the comparison between the VSB simulation results with traditional procedures that do not consider the operational continuity under a failure scenario confirms the strength and precision of the proposal for complex systems.

Collaborative Video-Based Learning Using Tablet Computers to Teach Job Skills to Students with Intellectual Disabilities

Information and Communication Technologies (ICT) provide different opportunities to students with intellectual disabilities and to professionals who work with them. However, few studies address the use of collaborative learning platforms and handheld devices to enhance the integration of people with intellectual disabilities in the labour market. We present a learning experience where active methodologies, such as collaborative work, are combined with the use of iPads and a learning management system following a video self-modelling methodology. The goal of this study was to determine whether the combination of traditional methodologies and new could be appropriate for students with intellectual disabilities and how they behave when having to rate their partner’s work. The results show that the combination of active learning methodologies, video self-modelling and the use of learning platforms and tablets is promising for teaching job related skills to students with intellectual disabilities, as participants experienced increased motivation to complete the tasks, improving their skills in the process.

Identification of the Program Text and Algorithm Correspondence Based on the Control Graph Constructive-Synthesizing Model

Purpose.The main article purpose is to develop and implement the method for identifying the correspondence between the text and the program algorithm represented in the form of a flowchart. As part of the method work conversion of the input data in the graph representation is performed by means of constructive-synthesizing modelling. Methodology. To compare the program text and flowchart, we constructed a mathematical model for converting the program code into a graphical representation on the basis of control structures. To build the model, the apparatus of constructive-synthesizing modeling and its methods were used: specialization, concretization, interpretation and implementation. The graph representation of the text is created taking into account the control operators; the flowcharts are created using a json file containing the description of the diagram elements and their links. To compare the graphs we use the breadth-first search algorithm with the number of identical vertices being counted. To obtain the software implementation of the developed method and models we used the technology of object-oriented programming and CASE-technologies, which are based on the unified modeling language UML. Findings A method is proposed to present the text and the flowchart of the program in a uniform format of the directed graph (control graph) and to evaluate their correspondence by the number of identical vertices. For its formalization and automated usage, we developed constructive-synthesizing models of input data transformers. The program application was developed based on the models and the method. Originality. The methods of constructive-synthesizing modeling in the tasks of processing texts written in artificial languages were further developed. We developed the system of constructors, which transforms text program in C++ into a control graph. Practical value. The results are significant for solving such tasks as assembling program texts for borrowings detection, determining the correspondence of the program algorithms and their software implementations to improve coding skills. The graph representation produced by the developed system of constructors can be used for investigation of influence of optimization and code refactoring on the program complexity using McCabe's metrics.