| 1. |
- De Colle, Mattia, et al.
(author)
-
Study of the Dissolution of Stainless-Steel Slag Minerals in Different Acid Environments to Promote Their Use for the Treatment of Acidic Wastewaters
- 2021
-
In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 11:24
-
Journal article (peer-reviewed)abstract
- Several stainless-steel slags have been successfully employed in previous studies as substitutes for lime in the treatment of industrial acidic wastewaters. This study deepens the knowledge of such application, by analyzing the neutralizing capacity of different slags related to their mineral compositions. To do so, firstly the chemical and mineral compositions of all the slag samples are assessed. Then, 0.5 g, 1 g, 2 g of each slag and 0.25 g and 0.5 g of lime are used to neutralize 100 g of 0.1 M HCl or HNO3 solutions. After the has neutralization occurred, the solid residues are extracted and analyzed using XRD spectroscopy. Then, the solubility of the minerals is assessed and ranked, by comparing the XRD spectra of the residues with the obtained pH values. The results show that minerals such as dicalcium silicate and bredigite are highly soluble in the selected experimental conditions, while minerals such as merwinite and akermanite, only partially. Moreover, Al-rich slags seem to perform poorly due to the formation of hydroxides, which generate extra protons. However, when the weight of slag is adequately adjusted, Al-rich slags can increase the pH values to higher levels compared to the other studied slags.
|
|
| 2. |
- Feith, Marek, et al.
(author)
-
Quantitative Phase Dynamics of Cancer Cell Populations Affected by Blue Light
- 2020
-
In: Applied Sciences. - : MDPI. - 2076-3417. ; 10:7, s. 1-13
-
Journal article (peer-reviewed)abstract
- Increased exposition to blue light may induce many changes in cell behavior and significantly affect the critical characteristics of cells. Here we show that multimodal holographic microscopy (MHM) within advanced image analysis is capable of correctly distinguishing between changes in cell motility, cell dry mass, cell density, and cell death induced by blue light. We focused on the effect of blue light with a wavelength of 485 nm on morphological and dynamical parameters of four cell lines, malignant PC-3, A2780, G361 cell lines, and the benign PNT1A cell line. We used MHM with blue light doses 24 mJ/cm(2), 208 mJ/cm(2) and two kinds of expositions (500 and 1000 ms) to acquire real-time quantitative phase information about cellular parameters. It has been shown that specific doses of the blue light significantly influence cell motility, cell dry mass and cell density. These changes were often specific for the malignant status of tested cells. Blue light dose 208 mJ/cm(2) x 1000 ms affected malignant cell motility but did not change the motility of benign cell line PNT1A. This light dose also significantly decreased proliferation activity in all tested cell lines but was not so deleterious for benign cell line PNT1A as for malignant cells. Light dose 208 mJ/cm(2) x 1000 ms oppositely affected cell mass in A2780 and PC-3 cells and induced different types of cell death in A2780 and G361 cell lines. Cells obtained the least damage on lower doses of light with shorter time of exposition.
|
|
| 3. |
- Garces, Alejandro, et al.
(author)
-
A Mixed-Integer Quadratic Formulation of the Phase-Balancing Problem in Residential Microgrids
- 2021
-
In: Applied Sciences. - : Multidisciplinary Digital Publishing Institute. - 1454-5101 .- 2076-3417. ; 11:5
-
Journal article (peer-reviewed)abstract
- Phase balancing is a classical optimization problem in power distribution grids that involve phase swapping of the loads and generators to reduce power loss. The problem is a non-linear integer and, hence, it is usually solved using heuristic algorithms. This paper proposes a mathematical reformulation that transforms the phase-balancing problem in low-voltage distribution networks into a mixed-integer convex quadratic optimization model. To consider both conventional secondary feeders and microgrids, renewable energies and their subsequent stochastic nature are included in the model. The power flow equations are linearized, and the combinatorial part is represented using a Birkhoff polytope B3 that allows the selection of phase swapping in each node. The numerical experiments on the CIGRE low-voltage test system demonstrate the use of the proposed formulation.
|
|
| 4. |
- Herrera-Brinez, Maria Camila, et al.
(author)
-
The Equivalence between Successive Approximations and Matricial Load Flow Formulations
- 2021
-
In: Applied Sciences. - : Multidisciplinary Digital Publishing Institute. - 1454-5101 .- 2076-3417. ; 11:7, s. 2905-
-
Journal article (peer-reviewed)abstract
- This paper shows the equivalence of the matricial form of the classical backward/forward load flow formulation for distribution networks with the recently developed successive approximations (SA) load flow approach. Both formulations allow solving the load flow problem in meshed and radial distribution grids even if these are operated with alternating current (AC) or direct current (DC) technologies. Both load flow methods are completely described in this research to make a fair comparison between them and demonstrate their equivalence. Numerical comparisons in the 33- and 69-bus test feeder with radial topology show that both methods have the same number of iterations to find the solution with a convergence error defined as 1×10−10.
|
|
| 5. |
- Lugnet, Johan, 1983-, et al.
(author)
-
Realization of Agile Methods in Established Processes : Challenges and Barriers
- 2021
-
In: Applied Sciences. - Switzerland : MDPI. - 2076-3417. ; 11:5
-
Journal article (peer-reviewed)abstract
- This paper presents an explorative study and the results of 17 interviews with informants from different companies. Its purpose is to identify the challenges associated with implementing agile methods along with the established procedures for early design. The study exemplifies project leaders’ experiences and implementation efforts. As leaders of design projects, they have proposed the use of a new method that involves teams engaging in testing and evaluation, which aids in the understanding and introduction of change initiatives. The challenges that are identified are as follows: (1) a lack of approval not only from top managers but also from critical peers; (2) an unprepared organization that did not allow teamwork; and (3) a lack of specific company success factors to support new methods.
|
|
| 6. |
- Montoya, Oscar Danilo, et al.
(author)
-
Genetic-Convex Model for Dynamic Reactive Power Compensation in Distribution Networks Using D-STATCOMs
- 2021
-
In: Applied Sciences. - : Multidisciplinary Digital Publishing Institute. - 1454-5101 .- 2076-3417. ; 11:8, s. 3353-
-
Journal article (peer-reviewed)abstract
- This paper proposes a new hybrid master–slave optimization approach to address the problem of the optimal placement and sizing of distribution static compensators (D-STATCOMs) in electrical distribution grids. The optimal location of the D-STATCOMs is identified by implementing the classical and well-known Chu and Beasley genetic algorithm, which employs an integer codification to select the nodes where these will be installed. To determine the optimal sizes of the D-STATCOMs, a second-order cone programming reformulation of the optimal power flow problem is employed with the aim of minimizing the total costs of the daily energy losses. The objective function considered in this study is the minimization of the annual operative costs associated with energy losses and installation investments in D-STATCOMs. This objective function is subject to classical power balance constraints and device capabilities, which generates a mixed-integer nonlinear programming model that is solved with the proposed genetic-convex strategy. Numerical validations in the 33-node test feeder with radial configuration show the proposed genetic-convex model’s effectiveness to minimize the annual operative costs of the grid when compared with the optimization solvers available in GAMS software.
|
|
| 7. |
- Montoya, Oscar Danilo, et al.
(author)
-
Reduction of Annual Operational Costs in Power Systems through the Optimal Siting and Sizing of STATCOMs
- 2021
-
In: Applied Sciences. - : MDPI AG. - 1454-5101 .- 2076-3417. ; 11:10, s. 4634-
-
Journal article (peer-reviewed)abstract
- The problem of the optimal siting and placement of static compensates (STATCOMs) in power systems is addressed in this paper from an exact mathematical optimization point of view. A mixed-integer nonlinear programming model to present the problem was developed with the aim of minimizing the annual operating costs of the power system, which is the sum of the costs of the energy losses and of the installation of the STATCOMs. The optimization model has constraints regarding the active and reactive power balance equations and those associated with the devices’ capabilities, among others. To characterize the electrical behavior of the power system, different load profiles such as residential, industrial, and commercial are considered for a period of 24 h of operation. The solution of the proposed model is reached with the general algebraic modeling system optimization package. The numerical results indicate the positive effect of the dynamic reactive power injections in the power systems on annual operating cost reduction. A Pareto front was built to present the multi-objective behavior of the studied problem when compared to investment and operative costs. The complete numerical validations are made in the IEEE 24-, IEEE 33-, and IEEE 69-bus systems, respectively.
|
|
| 8. |
- Nyyssönen, Tuomo, et al.
(author)
-
Significance of Annealing Twins in Laser Ultrasonic Measurements of Grain Size in High-Strength Low-Alloy Steels
- 2023
-
In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 13:6
-
Journal article (peer-reviewed)abstract
- In this study, we demonstrate the significance of austenite annealing twin boundaries when calibrating laser ultrasonic measurements for gauging austenite grain size in situ during the thermomechanical processing of high-strength low-alloy steels. Simple calculations show how differences in twinning density can lead to errors in grain size measurements if twins are disregarded during calibration and the method is used for a broad range of steels. Conversely, when calibration is performed using alloys with a metastable austenite microstructure at room temperature, the same calibration is suitable for a broad range of HSLA steels, provided that annealing twins are taken into account. Since light optical microscopy does not allow the characterization of annealing twins in low-alloy steel, the verification of the laser ultrasonic results was conducted using the novel approach of comparing the twinned grain sizes obtained using the ultrasonic method in low-alloy steels with the austenite grain maps reconstructed from martensite orientation maps measured using electron backscatter diffraction. Finally, we show how differences in twinning density occur even for alloys with a roughly similar stacking fault energy, further highlighting the importance of annealing twins in the calibration of laser ultrasonic measurements for industrial use.
|
|
| 9. |
- Pudar, Ranko, et al.
(author)
-
Evaluation of Green and Grey Flood Mitigation Measures in Rural Watersheds
- 2020
-
In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 10:19, s. 1-25
-
Journal article (peer-reviewed)abstract
- Floods cause considerable damages worldwide and mitigation of their adverse effects through effective protection measures is needed. Along with the commonly applied “grey” infrastructure, “green” measures that can offer additional benefits, such as ecosystem services, are increasingly being considered lately. While the recent research tendencies are focused on the effectiveness and the value of green measures in urban areas, this paper presents a comprehensive financial evaluation of green and grey flood mitigation scenarios for a smaller rural watershed. A micro-scale damage model that builds on the hydrodynamic modeling of hazard, detailed asset identification, and damage assessment is presented and applied for evaluation of benefits from various flood mitigation measures in the Tamnava watershed in Serbia. Four scenarios are considered: (1) existing flood protection system; (2) green scenario involving new detention basins; (3) grey infrastructure enhancement by rising of the existing levees and diverting flood discharges; and (4) green-grey scenario that combines scenarios (2) and (3). The benefits (loss reduction) are the greatest with the green scenario and marginally higher with the combined green-grey scenario. The results suggest that for small rural watersheds, a holistic, integrative approach that includes both types of infrastructure can provide the most effective flood risk mitigation.
|
|
| 10. |
- Cai, Huanchen, et al.
(author)
-
Mapping Phonation Types by Clustering of Multiple Metrics
- 2022
-
In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 12:23, s. 12092-
-
Journal article (peer-reviewed)abstract
- For voice analysis, much work has been undertaken with a multitude of acoustic and electroglottographic metrics. However, few of these have proven to be robustly correlated with physical and physiological phenomena. In particular, all metrics are affected by the fundamental frequency and sound level, making voice assessment sensitive to the recording protocol. It was investigated whether combinations of metrics, acquired over voice maps rather than with individual sustained vowels, can offer a more functional and comprehensive interpretation. For this descriptive, retrospective study, 13 men, 13 women, and 22 children were instructed to phonate on /a/ over their full voice range. Six acoustic and EGG signal features were obtained for every phonatory cycle. An unsupervised voice classification model created feature clusters, which were then displayed on voice maps. It was found that the feature clusters may be readily interpreted in terms of phonation types. For example, the typical intense voice has a high peak EGG derivative, a relatively high contact quotient, low EGG cycle-rate entropy, and a high cepstral peak prominence in the voice signal, all represented by one cluster centroid that is mapped to a given color. In a transition region between the non-contacting and contacting of the vocal folds, the combination of metrics shows a low contact quotient and relatively high entropy, which can be mapped to a different color. Based on this data set, male phonation types could be clustered into up to six categories and female and child types into four. Combining acoustic and EGG metrics resolved more categories than either kind on their own. The inter- and intra-participant distributional features are discussed.
|
|
