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1

Assessment of transient flow behavior and sensitivity analysis in the Al-Hashimiyah water treatment pipeline system using an integrated method of characteristics

Kadhim Hayder Mohammed, Shamkhi Mohammed S., Naje Ahmed Samir

Advances in Science and Technology. Research Journal

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2026

|

Vol. 20, no. 8

130--145

EN

This study investigates transient flow behavior and the sensitivity of key hydraulic parameters in the Al-Hashimiyah water transmission pipeline under steady and unsteady flow conditions. Steady-state analysis yielded a flow velocity of 5.66 m/s, a Reynolds number of 1.18 × 10⁶, and a Darcy-Weisbach friction factor of 0.008, with total head losses remaining below the allowable 70 m limit. A hybrid numerical model integrating the Method of Characteristics and Method of Integration (MOC–MOI) was developed and validated to simulate transient events, including sudden valve closures and pump shutdowns. Transient analysis indicated peak surge pressures of 205.13 m at a discharge of 0.34 m³/s, exceeding the safe operating range, while lower discharges (0.111 m³/s) limited surge pressures to 65.56 m. Pump failures induced severe pressure drops, with fluctuations reaching 95.9% of the initial head, generating negative pressures that risk cavitation. A surge tank (12 m diameter, 15 m height, 1,700 m³ volume) positioned 70 m downstream of the pumping station reduced peak pressures by 24.6%. Sensitivity analysis revealed that increasing pipe diameter from 0.24 m to 0.35 m reduced surge pressures from 191.21 m to 122.32 m, while higher friction (0.003–0.012) decreased surges from 187.40 m to 149.80 m. These findings confirm that the MOC–MOI model reliably predicts transient hydraulic behavior and provides an effective tool for design optimization, risk assessment, and operational planning in water transmission pipelines.

2

High-symmetry-point dispersion sensitivity analysis of quasi-Rayleigh waves in periodic half-spaces

Doliński Łukasz, Piwowarczyk Bartłomiej, Paćko Paweł, Torrent Daniel

Technical Transactions

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2025

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Vol. 122, iss. 1

art. no. e2025026

EN

This work investigates the sensitivity of surface-wave dispersion characteristics in periodic phononic structures with two types of scatterers: cylindrical pillars and finite-depth circular holes. We develop high-fidelity finite element models of square unit cells with Bloch boundary conditions and analyse the effect of geometric parameters (diameter and height/depth) on eigenfrequencies at a Brillouin zone high-symmetry point. A global sensitivity analysis based on the one-factor-at-a-time method is performed to quantify parameter influence and non-linear interactions. The results show that, for pillar-type structures, the pillar height dominates the dynamic response, while for hole-type structures both diameter and depth have comparable effects. Large geometric variations lead to mode reordering and narrow frequency separations, which is critical for bandgap-oriented optimisation. The approach outlines a route towards tunable phononic platforms for wave-based imaging applications.

3

Influence of random variable correlation on the reliability of steel structures

Dudzik Agnieszka

Structure and Environment

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2025

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Vol. 17, no. 3

103--112

EN

The study investigated the influence of correlations between random variables on the reliability index of selected structural systems. The structural design parameters were defined as deterministic quantities and random variables, and the correlation between them was modeled using four correlation-matrix variants. The ultimate limit state was adopted as the safety criterion, and appropriate limit state functions were formulated to identify structural failure. A sensitivity analysis of the reliability index with respect to the random variables was carried out using the Hasofer-Lind reliability index as the performance measure. The First-Order Reliability Method served as the primary computational approach, with Monte Carlo simulation as the reference method. All calculations were performed using the NUMPRESS Explore. The analyses demonstrated that increasing the correlation coefficient leads to higher values of the reliability index. The results confirm that the correlation coefficient significantly affects the reliability assessment and should not be neglected in structural safety evaluations.

PL

W pracy analizowano wpływ korelacji zmiennych losowych na wartość wskaźnika niezawodności wybranych układów konstrukcyjnych. Parametry projektowe konstrukcji zdefiniowano jako wielkości deterministyczne oraz zmienne losowe. W analizie uwzględniono korelację zmiennych losowych poprzez zastosowanie czterech wariantów macierzy korelacji. Stan graniczny nośności przyjęto jako kryterium oceny bezpieczeństwa konstrukcji, a do identyfikacji stanu awarii zastosowano odpowiednie funkcje graniczne. Przeprowadzono analizę wrażliwości wskaźnika niezawodności względem zmiennych losowych, przyjmując wskaźnik Hasofera-Linda jako miarę niezawodności. Podstawową metodą obliczeniową była metoda niezawodności pierwszego rzędu (FORM), natomiast metodę Monte Carlo wykorzystano jako metodę referencyjną. Obliczenia przeprowadzono z wykorzystaniem oprogramowania NUMPRESS Explore. Na podstawie przeprowadzonych analiz zaobserwowano, że wzrost wartości współczynnika korelacji prowadzi do zwiększenia wartości wskaźnika niezawodności. Uzyskane wyniki potwierdziły, że współczynnik korelacji wywiera istotny wpływ na wartość wskaźnika niezawodności, wobec czego nie powinien być pomijany w ocenie bezpieczeństwa konstrukcji.

4

Sensitivity analysis of social profit from cereal grain dryer’s energy modernization

Knutel Bernard, Bukowski Przemysław, Wojtko Paulina

Rynek Energii

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2025

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Nr 1

78--82

EN

The article presents the sensitivity analysis results of the SROI social profit indicator resulting from implementing 3 energy modernizations in a drying facility. As part of the research, a set of 10 independent variables were identified that describe an energy-saving project and may affect its social profitability. They were energy, economic, environmental and social parameters. The sensitivity analysis identified the direction and strength of the impact of fluctuations in selected variables on the meter's value. The SROI indicator for the analyzed investment was the most sensitive to changes in investment outlays, showing a negative correlation.

PL

Artykuł przedstawia rezultaty przeprowadzonej analizy wrażliwości wskaźnika zysku społecznego SROI wynikającego z wdrożenia w obiekcie suszarniczym 3 modernizacji energetycznych. W ramach przeprowadzonych badań zidentyfikowano zestaw 10 zmiennych niezależnych opisujących przedsięwzięcie energooszczędne i mogących oddziaływać na jego opłacalność społeczną. Stanowiły je parametry o charakterze energetycznym, ekonomicznym, środowiskowym i socjalnym. Poprzez przeprowadzoną analizę czułości zidentyfikowano kierunek i siłę oddziaływania wahań wybranych zmiennych na wartość miernika. Wskaźnik SROI dla analizowanej inwestycji był najbardziej wrażliwy na zmianę nakładów inwestycyjnych wykazując korelacje ujemną.

5

Photovoltaics output model with independent weather factors. Implications for the capacity management and its sensitivity analysis

Brzęczek Tomasz

Rynek Energii

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2025

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Nr 4

98--104

EN

Businesses and households that operate photovoltaics became prosumers of energy. A prosumer produces solar energy for self-consumption and exports production surplus to the grid. When consumption exceeds production the missing energy is imported from the grid. We analyze the photovoltaics stand-alone optimal capacity for which energy flows between a prosumer and the grid compensate fully. This considers that net-metering equals 0 and export to the grid is balanced with import from the grid. Under net-billing energy export is subject to financial risk due to market price. However, installation of energy warehouse of appropriate capacity mitigates this problem. We apply the optimization model known from the literature although verified here with empirical hourly output during whole year and its generalized least squares regression. We propose how to measure risk of energy flows imbalance with confidence interval for mean efficiency of photovoltaics. Additionally, costs relation range for the optimal capacity solution is considered. The bigger the estimate is the smaller the output risk is and the shorter is optimal capacity interval. We control results for weather independent variables such as wind, air pressure, temperature and humidity.

PL

Przedsiębiorstwa i gospodarstwa domowe, które eksploatują fotowoltaikę, stały się prosumentami energii. Prosument produkuje energię słoneczną na potrzeby własne, a nadwyżki produkcyjne eksportuje do sieci. Gdy zużycie przewyższa produkcję, brakująca energia jest importowana z sieci. Analizujemy wolnostoj ącą moc optymalną fotowoltaiki, dla której przepływy energii między prosumentem a siecią W pełni kompensują przepływy energii. Zakłada to, że net-metering jest równy 0, a eksport do sieci jest równoważony importem z sieci. W ramach net-billingu eksport energii jest obarczony ryzykiem finansowym ze względu na cenę rynkową. Jednak instalacja magazynu energii o odpowiedniej pojemności łagodzi ten problem. Stosujemy model optymalizacyjny znany z literatury, choć tutaj zweryfikowany empirycznymi wynikami godzinowymi w ciągu całego roku i jego uogólnioną regresja metodą najmniejszych kwadratów. Podpowiadamy, w jaki sposób mierzyć ryzyko niezbilansowania przepływów energii za pomocą przedziału ufności dla średniej sprawności fotowoltaiki. Dodatkowo brany jest pod uwagę zakres relacji kosztów dla optymalnego rozwiązania wydajnościowego.” Im większe jest oszacowanie, tym mniejsze jest ryzyko produkcji i tym krótszy jest optymalny przedział wydajności. Kontrolujemy wyniki dla zmiennych niezależnych od pogody, takich jak wiatr, ciśnienie powietrza, temperatura i wilgotność.

6

Fault diagnosis based on improved information entropy and 1DCNN for marine turbocharger rotor with variable speed

Hu Lei, Hu Haoran, Hu Nao, Liu Luyuan, Dong Fei, Yang Jianguo, Zhong Jiahong

Polish Maritime Research

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2025

|

nr 3

118--130

EN

Due to the lack of a standardised method for determining representative locations for measuring points, it is difficult to select sensitive data on turbocharger rotor faults. In addition, the uncertainty in the feature parameters used for diagnosis under variable rotational speeds leads to low accuracy in fault identification. To address these issues, vibration signals from a turbocharger rotor under various conditions are obtained in this study via a fault simulation test, and a fault diagnosis method for rotor faults under variable speed conditions is proposed based on a sensitivity and multi-dimensional feature analysis of measurement points. The sensitivity of the improved and traditional information entropy is evaluated using a variance analysis across the measurement points, and the most effective vibration measurement points are selected based on the improved information entropy. The effective characteristic parameters of the vibration signals at multiple measurement points are analysed and extracted, and the numer of dimensions of the feature parameters is reduced using the t-distributed stochastic neighbour embedding (t-SNE) method. Faults in the turbocharger rotor at the different speeds are classified using a one-dimensional convolutional neural network (1DCNN), and the arithmetic ability of the diagnostic algorithm is evaluated. The results demonstrate that the proposed methods of selecting measurement points and fault diagnosis can effectively identify rotor faults at different degrees and various speeds: the accuracy of fault diagnosis is 99.85%, and the arithmetic ability is markedly enhanced compared with that of traditional methods.

7

Experimental and Numerical Investigation of the Stiffness of the FPR Composite Mast of an A-Class Catamaran (A-Cat) with Sensitivity Analysis

Ferenc Tomasz, Mikulski Tomasz

Polish Maritime Research

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2025

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nr 4

132--141

EN

The paper presents an experimental and numerical investigation of the stiffness of an A-class catamaran (A-Cat) mast. The structure has a constant, prismatic cross-section and is made from fibre-reinforced plastic (FRP) multilayered laminate. The material parameters of the structure were identified. Then, static tests were conducted using a simply supported beam configuration, where supports were established at the beginning of the mast length and at the rigging attachment point. A computational model of the mast was created and analysed using the finite element method (FEM). A sensitivity analysis was performed on a validated model, from which sensitivity coefficients were obtained. On this basis, it was possible to determine how the structure could be modified to obtain the expected deformation, i.e. the maximum displacement of a selected point on the mast or the shape of the mast bending under a given load.

8

Measurement models - theory and practice of uncertainty evaluation of geometrical deviation measurements

Wojtyła Mirosław, Płowucha Wojciech

Metrology and Measurement Systems

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2025

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Vol. 32, nr 3

art. no. 2, 1--21

EN

The publication provides a critical analysis of fundamental documents concerning the determination of measurement uncertainty from the perspective of the machinery industry. The requirements contained in the documents JCGM 104, JCGM 100, and JCGM 101 were compared with important documents used in geometrical measurements, particularly with EA-4/02, ISO 14253-2, ISO/TS 15530-1, ISO 15530-3, ISO/TS 15530-4, and VDI/VDE 2617-11. Significant differences between the documents analysed, both terminological and interpretative, were highlighted. The analysis was performed in the sequence of stages for determining measurement uncertainty: formulation, propagation, and summarizing. Special attention was paid to the problem of defining the measurement model and the insufficient reference to the measurement model in the analysed documents. Attention was drawn to the wide range of characteristics measured in the machinery industry, such as linear and angular dimensions and form, orientation, position, and runout deviations, as well as the wide range of measurement equipment used, from simple instruments like callipers, micrometers, and mechanical dial gauges, to coordinate measuring machines and measurement systems. The current approach to the uncertainty of coordinate measurements, including the new possibility of modelling coordinate measurement, was discussed.

9

Sensitivity analysis of multiobjective linear programming from a geometric perspective

Kaci Mustapha

Mathematica Applicanda

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2025

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Vol 53, no. 1

45--67

EN

Sensitivity analysis plays a crucial role in multiobjective linear programming (MOLP), where understanding the impact of parameter changes on efficient solutions is essential. This work builds upon and extends previous investigations. In this paper, we introduce a novel approach to sensitivity analysis in MOLP, designed to be computationally feasible for decision-makers studying the behavior of efficient solutions under perturbations of objective function coefficients in a two-dimensional variable space. This approach classifies all MOLP problems in $S \subset \mathbb{R}^{2}$ by defining an equivalence relation that partitions the space of linear maps-comprising all sequences of linear forms on $\mathbb{R}^2$ of length $K \geq 2$-into a finite number of equivalence classes. Each equivalence class is associated with a unique subset of the boundary of $S$. For any MOLP with $K$ objective functions belonging to the same equivalence class, its set of efficient solutions corresponds to the associated subset of the boundary of $S$. This approach is detailed and illustrated with a numerical example.

PL

Analiza wrażliwości odgrywa kluczową rolę w wielokryterialnym programowaniu liniowym (MOLP), gdzie zrozumienie wpływu zmian parametrów na rozwiązania efektywne jest niezwykle istotne. Niniejsza praca opiera się na wcześniejszych badaniach i je rozwija. W artykule przedstawiamy nowatorskie podejście do analizy wrażliwości w MOLP, które zostało zaprojektowane tak, aby było wykonalne obliczeniowo dla decydentów badających zachowanie rozwiązań efektywnych w przypadku zakłóceń współczynników funkcji celu w przestrzeni zmiennych dwuwymiarowych. Podejście to klasyfikuje wszystkie problemy MOLP w S ⊂ R2, definiując relację równoważności, która dzieli przestrzeń odwzorowań liniowych - obejmującą wszystkie ciągi form liniowych na R2 o długości K ≥ 2 - na skończoną liczbę klas równoważności. Każda klasa równoważności jest powiązana z unikalnym podzbiorem brzegu S. Dla dowolnego problemu MOLP z K funkcjami celu należącymi do tej samej klasy równoważności, jego zbiór rozwiązań efektywnych odpowiada powiązanemu podzbiorowi brzegu S. Podejście to jest szczegółowo opisane i zilustrowane za pomocą przykładu numerycznego.

10

Sensitivity analysis of input variables in an ANN model for predicting curtain wall costs

Górka-Stańczyk Monika, Sagan Joanna

Materiały Budowlane

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2025

|

nr 12

54--60

EN

Assess the importance of input variables in an artificial neural network (ANN) model designed to predict the costs of curtain walls. The analysis was carried out on the basis of 209 contract documents of public utility buildings located in central and southern Poland. Out of 28 initially identified factors, 24 variables describing the technical parameters of the buildings and the types of facade materials were selected for the construction of the ANN model. The global sensitivity analysis of the model revealed that the most critical cost-determining factor for facade systems is the facade area. Due to the low significance levels of other variables, input variable selection was conducted, showing that a reduced model with 16 variables retained a quality comparable to that of the full 24-variable model. In addition, a simulation was carried out to assess the impact of the most significant variables on the SSN model. The results confirm that the SSN responds appropriately to changes in the input variables and further serves as an effective tool for predicting the costs of façade systems.

PL

Oceniono znaczenie zmiennych wejściowych w modelu sztucznej sieci neuronowej (SSN) prognozującej koszty ścian osłonowych. Analizę przeprowadzono na podstawie 209 dokumentacji kontraktowych budynków użyteczności publicznej zlokalizowanych w centralnej i południowej Polsce. Spośród 28 zidentyfikowanych czynników, po selekcji wykorzystano 24 zmienne opisujące parametry techniczne obiektów i rodzaje materiałów elewacyjnych do budowy modelu sztucznej sieci neuronowej. Globalna analiza wrażliwości modelu SSN wykazała, że kluczowym czynnikiem determinującym koszty systemów fasadowych jest powierzchnia elewacji. Ze względu na niski poziom istotności pozostałych zmiennych przeprowadzono selekcje zmiennych wejściowych modelu sztucznej sieci neuronowej, gdzie w przypadku 16 zmiennych wejściowych jakość modelu pozostała na porównywalnym poziomie jak w przypadku 24 zmiennych. Ponadto wykonano symulację wpływu najistotniejszych zmiennych na model SSN. Badania potwierdzają, że SSN prawidłowo reaguje na zmianę zmiennych wejściowych i stanowi skuteczne narzędzie prognozowania kosztów systemów elewacyjnych.

11

Application of machine learning classifiers to elastic wave signal analysis and diagnostics of bolted joints

Bróż Natalia, Nazarko Piotr

Materiały Budowlane

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2025

|

nr 6

91--97

EN

A laboratory model of a portal frame was tested. Piezoelectric transducers were used to excite and measure elastic waves. As a result, 2,100 patterns were collected for various connection state scenarios (7 classes). Subsequently, a multi‑level diagnostic system for fault detection and classification was developed. After training, it achieved flawless classification results, offering an alternative to previously applied approaches for this task SSN, ANN. Furthermore, it was demonstrated that the significance of the principal components does not correspond to their normalised order.

PL

Badaniom poddano laboratoryjny model ramy portalowej. Do wzbudzania i pomiaru fal sprężystych zastosowano przetworniki piezoelektryczne. W rezultacie zebrano 2100 wzorców różnych scenariuszy stanu połączenia (7 klas). Następnie zbudowano wielopoziomowy system diagnostyczny do wykrywania i klasyfikacji usterek. Po jego wytrenowaniu możliwe było uzyskanie bezbłędnych wyników klasyfikacji, co stanowi alternatywę dla wcześniej stosowanych w tym zadaniu podejść SSN, ANN. Ponadto wykazano, że istotność składników głównych nie jest tożsama z unormowaną ich kolejnością.

12

Sensitivity analysis of multiple eigenvalues and associated eigenvectors of quadratic eigenproblem

Ciurej Henryk

Journal of Theoretical and Applied Mechanics

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2025

|

Vol. 63 nr 4

721--736

EN

The article is focused on the sensitivity of eigenvalues and eigenvectors in a quadratic eigenvalue problem with real matrices defining the problem under consideration and under the strong assumption that these matrices form a non-defective operator. The particular interest is the case of multiple eigenvalues and associated eigenvectors. Generally in such a case derivatives in the Frechet sense do not exist, but only in the Gˆateaux sense. The formulas of the directional differential in the closed matrix form were derived. A numerical example is shown.

13

Case Study-Based Assessment of Carbon Footprint Reduction in Construction Materials Using BIM-Integrated LCA and Sensitivity Analysis

Adesope Samson Femi, Ostręga Anna, Borowski Marek

Inżynieria Mineralna

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2025

|

Vol. 2, no. 2

art. no. 14

EN

Achieving net-zero emissions is a fundamental goal for environmental sustainability and the transition to a circular economy. The construction and mining sectors contribute approximately one-third of global emissions, emphasizing the urgency of adopting effective mitigation strategies. Reducing the carbon footprint and CO₂ emissions in these industries is a critical challenge for promoting sustainable development and optimizing material usage. This study aims to quantify the carbon footprint of major building materials, specifically concrete, steel, and wood, assess potential CO₂ emission reductions, and evaluate their environmental impact. The research integrates Building Information Modeling (BIM), Life Cycle Assessment (LCA), and Sensitivity Analysis (SA) to establish environmental impact benchmarks. A case study approach was employed to analyse the carbon footprint of construction materials. The study utilized LCA to assess the embodied carbon at various life cycle stages (A1 to A3), identifying key contributors to global warming potential, acidification, eutrophication, and ozone depletion. Sensitivity analysis was conducted to evaluate the influence of material selection on overall emissions, while BIM integration facilitated a comprehensive visualization of the environmental impact. The analysis revealed that the embodied carbon from LCA stages A1 to A3 represents the primary contributor to environmental degradation. The study demonstrated a reduction in material-related carbon emissions from 662 kg CO₂e/m² to 506.8 kg CO₂e/m². Additionally, the global warming impact of building materials decreased from 10.57 kg CO₂e/m²/year to 8.45 kg CO₂e/m²/year. The results confirm that material type and quantity selected during the production stage significantly influence the overall embodied carbon. The findings of this study support sustainable decision-making in the construction industry by promoting material substitution strategies that replace high-emission components with low-carbon alternatives. The integration of BIM, LCA, and SA provides a robust framework for reducing environmental impact while fostering the reuse and recycling of construction materials. These insights contribute to advancing circular economy principles in the built environment. The above-mentioned analyses will be related to the possibilities of adapting the material mining heritage for new functions instead of constructing new buildings.

14

Sensitivity analysis and uncertainty quantification of stiffness modulus using indirect tensile test

Mezouara H., Zniker H., Feddal I., El Kouifat M. K., El Hasnaoui M.

International Journal of Applied Mechanics and Engineering

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2025

|

Vol. 30, no. 2

105--123

EN

The stiffness modulus is a critical element in pavement engineering, as its accurate measurement directly reflects the load-bearing capacity of the pavement section. Many researchers utilize indirect tensile tests in laboratory studies to determine this modulus. The pavement's performance, as well as other properties of the pavement layers, can be directly influenced by this modulus. It also provides insights into the resistance of the asphalt mix to permanent deformation due to repeated loads, a common issue in flexible pavements. The stiffness modulus holds a significant role in pavement and pavement materials-related works and designs. This research aims to address uncertainties in stiffness modulus measurements of asphalt mixtures, which can lead to unreliable results and poor decisions in pavement construction. The paper presents theoretical and experimental findings on the uncertainty and sensitivity analysis in identifying influential parameters in stiffness modulus measurement. Key factors such as experimental setup, interface roughness, sample shape, and plate-sample contact were evaluated for their impact on measurement uncertainty. The study found that test repeatability is the primary contributor to measurement error, accounting for approximately 79.72%, followed by thickness measurement, contributing around 19.75%.

15

The influence of tissue conductivity uncertainty on the nerve activation thresholds in non-invasive electrical phrenic nerve stimulation

Wegert Laureen, Di Rienzo Luca, Codecasa Lorenzo, An Sicheng, Ziolkowski Marek, Hunold Alexander, Lange Irene, Kalla Tim, Haueisen Jens

Biocybernetics and Biomedical Engineering

|

2025

|

Vol. 45, iss. 4

697--706

EN

Non-invasive phrenic nerve stimulation can be used to overcome diaphragm insufficiency caused by mechanical ventilation. Detailed models and electromagnetic simulations are used to suggest appropriate stimulation parameters, but require accurate tissue properties. However, a wide range of electrical conductivity values is known from the literature. Here, we aim to perform an uncertainty analysis of the nerve activation threshold and the potential distribution along the phrenic nerve due to uncertain tissue conductivites. We built a generalized polynomial chaos (gPC) model to calculate the phrenic nerve activation threshold. It was based on a reduced order model of a detailed anatomical finite element model of the neck including 13 tissue types to calculate the potential distribution, followed by a biophysiological nerve model. The tissue conductivity values investigated here were for the compartments of fat, muscle, nerve, and soft tissue. Their influence on the nerve activation threshold was investigated by changing conductivity values of the single tissues and all tissues at a time within a Monte Carlo analysis using the gPC model. The phrenic nerve activation threshold varied between 33.8mA and 46.9mA for the combined variation of the conductivity values. Sobol indices and global sensitivity coefficients indicated the highest influence for muscle conductivity value, followed by soft tissue, fat, and nerve tissue. Our results may have implications for understanding the experimentally observed variation in individual phrenic nerve activation thresholds affected by physiological and pathological conductivity changes. Accurate electric properties of muscle and soft tissue and detailed geometric representations should be considered in electromagnetic simulations.

16

Sensitivity Analysis of Magnetohydrodynamic Mixed Convective Trapezoidal Heat Exchanger Containing Hybrid Nanofluid: Numerical and Statistical Approach

Islam Saiful, Molla Goni, Neogi Badhan, Faiaz Muhammad, Rana B.M. Jewel, Molla Md. Mamun

Archives of Thermodynamics

|

2025

|

Vol. 46, no. 3

61--76

EN

The consequences of magnetohydrodynamic mixed convection in a trapezoidal heat exchanger are investigated through numerical analysis. Due to the extensive applications of both mono and hybrid nanofluids in manufacturing and thermal engineering, the Ag-MgO-H2O hybrid nanofluid is selected as the working material for the entire domain. Additionally, a horizontal magnetic field is applied to the cavity. The finite element method is involved to solve the corresponding mathematical equations. The physical implications of the results are examined over a range of Reynolds numbers (10 ≤ Re ≤ 200), Hartmann numbers (0 ≤ Ha ≤ 100), and nanoparticle volume fractions (0 ≤ ϕ ≤ 0.08) using streamlines, isotherms, and line graphs. The impact of key factors on the response function is illustrated using the response surface methodology with 2D and 3D visualizations. Sensitivity rates are analysed by developing a best-fit correlation. It is concluded that the thermal enhancement of the hybrid nanofluid is achieved up to 11.4% by incorporating hybrid nanoparticles, and due to the upsurge of the Reynolds number. Conversely, the influence of the magnetic field leads to a decline in this rate to 10.02%. The use of Ag-MgO-H2O hybrid nanofluid improves the heat transfer efficiency of water by 6.62%. Finally, the results of this study may offer valuable insights for designing an efficient mixed convective mechanical device.

17

Sensitivity Analysis of Acoustic Parameters in a Theatre Hall : A Case Study of the Maria Zankovetska Theatre in Lviv

Rubacha Jarosław, Pilch Adam, Kinasz Roman, Binek Wojciech, Kamisiński Tadeusz, Melnyk Mykhaylo

Archives of Acoustics

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2025

|

Vol. 50, nr 3

307--320

EN

This article explores the potential for modifying acoustic parameters within a theatre hall, using the Maria Zankovetska Theatre in Lviv, as a case study. The study used sensitivity analysis to evaluate how changes in the sound absorption of specific surfaces affect selected acoustic parameters in the horseshoe-shaped theatre hall. A numerical model of the hall is developed and calibrated based on in-situ acoustic measurements to assess the sensitivity of parameters such as reverberation time (T20), early decay time (EDT), clarity (C50), and early sound strength (G80). The analysis reveals that surfaces such as the stage tower ceiling, stage walls with curtains, audience walls, and seating have the most significant impact on the acoustic parameters. Modifying the sound absorption of these surfaces can affect T20, EDT, C50, and G80. Notably, increasing the absorption of a single surface might not significantly alter C50 and G80 values, whereas reducing the absorption of surfaces such as seating can lead to noticeable changes in these parameters. These findings provide valuable insights for future renovations and acoustic adjustments, aiming to optimize the theatre’s acoustic performance while preserving its historical character.

18

Mechanical analysis and sensitivity evaluation of PLA scaffolds for bone tissue repair using FEA and Taguchi experimental design

Vásquez Diego, Medina Luis, Martínez Gabriela

Acta of Bioengineering and Biomechanics

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2025

|

Vol. 27, no. 1

69--81

EN

The design of three-dimensional scaffolds for bone regeneration poses challenges in balancing mechanical strength, porosity and degradability. This study aimed to optimize the geometric parameters of polylactic acid (PLA) scaffolds fabricated via 3D printing, focusing on pore size, porosity, and geometric configurations to enhance mechanical performance and biological functionality. Methods: Two geometric configurations – orthogonal and offset orthogonal – were evaluated with pore sizes ranging from 400–1000 μm and porosities between 55–70%. Finite element analysis (FEA) in ANSYS Workbench was used to simulate mechanical behavior, while the Taguchi experimental design determined the optimal parameter combinations. Statistical analyses, including ANOVA, assessed the significance of each factor. Results: The study identified a pore size of 400 μm as optimal for structural strength, while a porosity of 70% provided a balance between stability and cell growth. Orthogonal geometries distributed stress more uniformly, reducing critical stress concentrations compared to offset configurations. ANOVA revealed that pore size was the most significant factor, followed by porosity and geometry, achieving a model reliability of R2 = 98.42%. Conclusions: The findings highlight the importance of geometric optimization for improving scaffold mechanical properties while maintaining biological functionality. This study offers a robust framework for designing patient-specific scaffolds tailored to bone tissue engineering applications.

19

Decision-making in major investment projects with a life cycle cost: improvement with sensitivity analysis and sustainability assessment

Wieke Stefan

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2024

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Vol. 33, No. 3

227--242

EN

This study focuses on compressor station investments in Germany’s natural gas infrastructure, offering insights applicable to machinery, energy, and maintenance cost-driven decisions. A life cycle cost (LCC) analysis can guide investment choices; however, uncertainties in input data and future developments pose risks. The LCC-based studies encounter questions impacting their results and optimal selections. These uncertainties may lead to misallocations, emphasizing the need for careful consideration of investment decisions to avoid potential consequences and efficiently allocate limited funds. Various measures are available to mitigate the uncertainties and risks in LCC analyses. Recognized measures are deterministic and probabilistic. Seven case studies on investments in the natural gas infrastructure in Germany were analyzed in this context. In addition to the executed case studies, a case study from a scientific journal (published in 2001) was included in the analysis. The case studies were conducted by transmission system operators from 2005–2015, and a retrospective view made it possible to recognize whether the best options (due to the LCC analysis) were identified. Simulations were conducted with generated models using real historical input data such as energy costs. The re-calculation of the net present value or better discounted cumulated expenditure with real input data shows that the LCC analysis results are significantly dependent on the reliability of the input data and the prediction of their development. Therefore, validating the results using appropriate measures is mandatory. This study illustrates how sensitivity analysis can be used as a deterministic method to evaluate the LCC analysis results. A company’s success is increasingly determined by its sustainability. A pure LCC analysis is insufficient, so social, ecological, and economic sustainability assessments must be conducted. This study demonstrates the effectiveness of the weighted scoring method for sustainability assessments. Although this study relates to LCC in Germany’s natural gas infrastructure, the suggested process can be adopted for other investment projects comprising capital and operational expenditures.

20

Stress assessment of a steel bullet LPG tank under differential settlement based on geodetic measurements and sensitivity analysis

Ferenc Tomasz, Gierasimczyk Rafał, Mikulski Tomasz

Polish Maritime Research

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2024

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nr 4

122--130

EN

This paper presents an analysis of a steel bullet LPG tank in operation at a base in Poland. The structure was set on a sand-gravel pillow and rigid concrete slab, and its settlement was periodically measured at five measuring points along the structure. After a few years, differential settlement was observed. Based on geodetic data, we attempt to assess the current stress level in the structure. The proposed methodology uses a sensitivity analysis apparatus. A numerical model of the structure and sand-gravel pillow is analysed using the finite element method, and the impact of variation in the stiffness of the sand-gravel pillow on the vertical displacement of the tank is determined. The algorithm involves six iterations of calculations, and after each iteration, the stiffness modified sand-gravel pillow is determined. After the sixth iteration, the vertical displacement in the FEM model is found to be similar to the measured values in the real structure. The results obtained after the last iteration are used to assess the stress state in the bullet tank’s shell structure.