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A Gentle Introduction to Physics-Informed Neural Networks, with Applications in Static Rod and Beam Problems
Get PDFA modern approach to solving mathematical models involving differential equations, the so-called Physics-Informed Neural Network (PINN), is based on the techniques which include the use of artificial neural networks and the method of fitting the governing differential equations at collocation points. In this paper, training of the PINN with an application of optimization techniques is performed on simple one-dimensional mechanical problems of elasticity, namely rods and beams. Different boundary conditions are considered.
Required computer algorithms are implemented using Python programming packages with the intention of creating neural networks. Numerical results are presented, and the efficiency of the proposed technique is investigated through numerical experiments with different numbers of epochs, batches, hidden layers, neurons, and collocation points.
The paper provides useful skills for using a PINN for different problems of solid mechanics. The proposed methodology is a continuation of our intention of using PINNs for problems of the theory of elasticity. The objectives are to present simply the main steps of constructing PINN and an implementation of it. A detailed explanation of the Python programming code, based on the scientific software Tensorflow, built in the Keras library and optimizers, may help compose an effective code for complicated models in mechanics.
PINNs are proposed in many recent publications to solve complicated direct and inverse problems. It seems to be a promising method that will play a central role in the development of computational mechanics in the near future. Nevertheless, the lack of educational material does not help new users to enter this scientific area. The present contribution describes the method for the solution of elementary rod and beam problems and gives computer codes that may help the reader to understand the method and to apply it to other problems
Stakeholders' Perception of Bioenergy Projects in Marginal and Underutilized Lands in Italy
Get PDFLarge land areas in European countries can be considered marginal, underutilized, and contaminated (MUC). Many recent studies have shown that bioenergy crop cultivation can make this land profitable, creating new income opportunities for local citizens without interfering with food production. However, farmers, landowners, and local communities must become more familiar with bioenergy systems, potential value chains, and markets. This paper aims to present the results of stakeholder consultations implemented in two case study areas in Italy, i.e., Basilicata and Sardinia, about the possible establishment of bioenergy systems in the MUC land available at the local level. Stakeholders' perceptions were collected through interviews conducted on a one-to-one basis and through multi-stakeholder working group meetings organized in the context of BIOPLAT-EU, an H2020 project aimed at promoting the efficacy and profitability of using MUC land for sustainable bioenergy production. By and large, the findings of the consultations indicate that local stakeholders are prone to accept the establishment of innovative bioenergy value chains based on the cultivation of MUC lands in their regions. The majority of them recognized that bioenergy could bring a wide range of benefits at the local level, not only in terms of environmental externalities but also of economic and social development, such as through the creation of new business and job opportunities, therefore serving to alleviate or prevent the land abandonment and population decline currently on-going in these areas
Water Scarcity and Work Constraints in Semi-Arid Agricultural Regions: Current Challenges and Future Intervention Strategies
Get PDFThis paper assesses the sustainability of agricultural water management in two contrasting regions of Morocco and examines the economic and volumetric water productivity of various crops and livestock products. Considering examples from the oasis areas in the East (Drâa oases) to the sub-humid Saïss plain in the North, we find that sustainable water use for certain crops may not be achievable due to intensive groundwater depletion. Furthermore, we show that livestock economic water productivity is often limited compared to crops, which may hide complex interactions between crops and livestock. These interactions provide diverse and steady sources of income for farmers, ensuring the resilience of farms in the face of climate, biotic, and economic risks. Our findings also suggest that the labor requirements of farming activities are burdensome, particularly for family members. Given the significant constraints affecting the agricultural sector, it would be too risky to continue promoting it as the main driver of the country's economy. The challenges posed by climate change and the need for more environmentally friendly practices mean that simple solutions cannot be relied upon for the future
Editorial: The Acoustic Characteristics of Religious Buildings
Get PDFThe acoustical experience of people in places of worship is not accurately captured by physical measures of building acoustics. While many studies concentrate on the acoustics of buildings, aural architecture analysis which provides a more thorough knowledge of the aural experience by considering perceptual and cultural factors in addition to physical ones receives less attention. Worship areas need intricate acoustical settings that enable both clear sound perception and the enjoyment of aesthetic sound. There is a need for more research on the relationship between the qualitative and quantitative acoustical features of religious buildings since this experience can have emotional consequences through the sense of sound
Solar Distiller Study for Freshwater Production by Seawater Desalination
Get PDFWater covers 70% of the planet Earth. Of the total volume of water on the planet, 2/3 (two-thirds) is in the form of ice or underground water. On the other hand, fresh water is an increasingly scarce resource in the world, with only 3% of the world's water being drinkable. Data from the United Nations (UN), indicate that approximately 1.1 billion inhabitants on planet Earth do not have access to fresh water. The same data also reveal that 2.7 billion inhabitants suffer from water scarcity for approximately one month a year. According to these data, water scarcity currently affects more than 40% of the world's population. This condition has driven the proposition of technological solutions to minimize the impact of difficulties in accessing this good [1].
Allied to all these aspects, in recent decades, industrial development and the growth of the world population have demanded a greater need for fresh water. At the same time, pollution and the reduction of surface water sources limit access to available freshwater resources [2].
Thus, there is a need for alternative water sources, leading to a focus on using previously technologies, with an emphasis on saltwater desalination. Many areas affected by freshwater scarcity are close to the sea, favoring implementing these technologies
Grid Search for SARIMAX Parameters for Photovoltaic Time Series Modeling
Get PDFThe SARIMAX (Seasonal Autoregressive Integrated Moving Average with eXogenous regressors) model is a time series model that can be used to forecast future values of a time series, given its past values. It is beneficial for modeling time series data that exhibits seasonality and incorporating additional exogenous variables (variables that are not part of the time series itself but may affect it).
One way to optimize the performance of a SARIMAX model is to use a grid search approach to find the best combination of hyperparameters for the model. A grid search involves specifying a set of possible values for each hyperparameter and then training and evaluating the model using all possible combinations of these values. The combination of hyperparameters that results in the best model performance can then be chosen as the final model. To perform a grid search for a SARIMAX model, you must define the grid of hyperparameters you want to search over. This will typically include the values of the autoregressive (AR) and moving average (MA) terms and the values of any exogenous variables you want to include in the model. We will also need to define a metric to evaluate the model's performance, such as mean absolute or root mean squared error.
Once we have defined the grid of hyperparameters and the evaluation metric, you can use a grid search algorithm (such as a brute force search or a more efficient method such as random search or Bayesian optimization) to evaluate the performance of the model using all possible combinations of hyperparameters. The combination of hyperparameters that results in the best model performance can then be chosen as the final model.
In this article, we will explore the potential of SARIMAX for PV time series modeling. The objective is to find the optimal set of hyperparameters. Grid Search passes all hyperparameter combinations through the model individually and checks the results. Overall, it returns the collection of hyperparameters that yield the most outstanding results after running the model. One of the most optimal SARIMAX (p,d,q) x (P, D, Q,s) combinations is SARIMAX (0,0,1) x (0,0,0,4)
Smart Switching Power Supply System for Evaporative Air Coolers
Get PDFThe energy consumption by residential air conditioners could cost about half of the total energy consumption of the building. A combination of conventional and renewable energy is still an emerging technology. Therefore, using solar photovoltaic panels to provide electricity to the air conditioner is a substantial application. This research shows the possibility of using photovoltaic panels as a power source for air conditioners in a sequence exchange with the conventional grid. A smart switching system has been offered to organize the power supply between the grid and solar panels. The photovoltaic panels have been connected to the conditioner across a power inverter module for adopting a reliable and accurate quantity of power supply to the conditioner unit. The smart switching system provides an intelligent connection between the solar power source and the grid, ensuring an uninterrupted electricity supply between the two power sources
Review on Performance Analysis of Desiccant-Assisted Hybrid Cooling Systems
Get PDFDue to the growing expense of fossil fuels and other environmental issues, it is crucial to reduce the energy cost of built environment cooling systems without sacrificing indoor air quality and comfort levels. One option in this area is solid desiccant dehumidification-assisted cooling systems, which employ alternative energy sources like solar and biomass and are also environmentally beneficial by the minimal requirement of refrigerants. The present review discusses the performance analysis of different solid desiccants readily accessible on the market and their composites. Better moisture absorption and a lower regeneration temperature are qualities of a better desiccant. The review also discusses the various solid desiccant dehumidifier designs, their benefits, and their disadvantages. Solid desiccant dehumidifiers now come in various combinations, considerably enhancing system performance. The exergy efficiency of desiccant-integrated evaporative cooling is up to 21.5%, comparable with another HVAC system. A summary of the performance parameters has also been created to assess system performance further. This study will benefit innovation and advancement in solid desiccant materials in the air conditioning market
Acoustical Evaluation of the Itacuruçá Baptist Evangelical Church
Get PDFThis paper presents the acoustical evaluation of a representative evangelical church in Rio de Janeiro, Brazil. The analysis, performed through measurements and simulations, has shown that the acoustic field needs to be more appropriate for the temple’s actual use. The analysis measured the impulse responses at 14 positions from 2 source locations and calculated Reverberation Time and Clarity Factor acoustic parameters. According to the literature and the ISO standards, the Reverberation Time was considered higher than the optimum value for both speech or music. An acoustic model for the temple was developed using the BRASS simulator. The simulation results were compared to measured data to validate the acoustic model. Based on that and aiming to achieve optimum acoustic parameters, a new model was proposed to evaluate alternatives to adequate the acoustical characteristics of the temple. The strategy to develop the final model and to achieve the target Reverberation Time is presented and discussed. An acoustic intervention is then proposed and evaluated using simulated data. The results obtained with the proposed changes, which considered the inclusion of perforated panels and carpet in some walls, were adequate, providing Reverberation Time in accordance to the standards and significant improvement to Clarity for music and speech
A Revised Comparison between Fama and French Five-Factor Model and Three-Factor Model——Based on China's A-Share Market
Get PDFIn allusion to some contradicting results in existing research, this paper selects China's latest stock data from 2005 to 2020 for empirical analysis. In this paper, the redundant factors (HML, CMA) are orthogonalized, and the regression analysis of the 5*5 portfolio of Size-B/M and Size-Inv is carried out with these two orthogonalized factors. It found that the HML and the CMA are still significant in many portfolios, indicating that they have a strong explanatory ability, which is also consistent with the results of GRS test. All these show that the five-factor model has a better ability to explain the excess return rate. Then, we analyze the possible reasons for the strong explanatory ability of the HML, CMA, and RMW from the aspects of price-to-book ratio, turnover rate, and correlation coefficient. We also explain the results and analyze China's stock market policy changes and investors' investment style in recent years