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Optimization of critical buckling load for variable stiffness composites using the lamination parameters as the field variables
No full textBuckling is a critical design concern for thin-walled structures and fiber-reinforced composite materials because it occurs with much lower strains than in failure. In this study, an in-house code is developed to optimize the critical buckling load using the lamination parameters as a design variable. The manufacturing steering curvature constraints are directly applied on the lamination parameters for the first time during optimization. The variable stiffness design revealed an approximately 160% improvement in the buckling load with respect to the optimal constant stiffness. The improvement in the critical buckling load ratio is over 400% with respect to the quasi-isotropic case, which is consistent with previous findings (Wu et al., 2015). The critical buckling load is 27% less when two opposite edges are clamped and two opposite edges are free compared to the ideal simply supported out-of-plane displacement boundary conditions that were used in previous optimization studies (Wu et al., 2015, Hao et al. 2019, Wu et al. 2012, Setoodeh et al. 2009, IJsselmuiden et al. 2010). The critical load ratio serves as the objective function when Neumann boundary conditions are employed, since membrane reactions remain unchanged throughout the optimization process, unlike in the case of Dirichlet boundary conditions. In addition, a widely accepted optimum fiber angle distribution, suggested in Gürdal et al. (2008), is implemented in a user-defined subroutine (UMAT) of Abaqus® to compare the buckling response of constant and variable stiffness of a plate
Behavioral but not psychological control predicts self-regulation, adjustment problems and academic self-efficacy among early adolescents
No full textPrior work has documented that parental psychological and behavioral control have varying impacts on self-regulation skills and social-academic outcomes in early adolescence, with effects differing across cultures. The present study explores the role of psychological and behavioral control in predicting adjustment difficulties and academic self-confidence through self-regulatory skills among early adolescents in Turkiye using data from mothers and their children (N = 295, Ngirls=145, Mage=12.14 years). The results yielded that parental behavioral control, but not psychological control, predicts self-regulation of adolescents, which, in turn, predicts adjustment and academic self-efficacy. Our results underscore the pivotal role of parental knowledge and monitoring, mainly through behavioral control strategies, in fostering psychological adjustment and academic self-efficacy in the Turkish cultural context. The discussion delves into the potential culture-specific effects of psychological control and the universal influence of behavioral control during early adolescence
Development of Peru balsam-enriched pectin-gellan gum films for sustainable antioxidant food packaging
No full textIn this study, the effects of Perubalsam extract (PBE) on the surface, physical, mechanical, barrier and antioxidant properties of pectin/Gelrite gellen gum (PGG) were evaluated. The developed films were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), and X-ray diffraction (XRD). Moreover, physiochemical properties, including moisture content, color, opacity, water solubility, and water vapor permeability, were measured. The antioxidant activity of the prepared films was determined by DPPH and ABTS radical scavenging assays. The incorporation of the extract into films increased opacity, thickness, elongation at break, water vapor permeability, and water solubility; however, tensile strength and moisture content decreased. SEM analysis revealed microstructural deformities like pores and cracks at higher concentrations of PBE. As expected, the antioxidant activities of the composite films increased with the increase in the PBE concentration in the films. Thus, such natural extract antioxidant films as a sustainable packaging material could offer better protection to the packed product against undesirable oxidation reactions
Comparative transcriptomic analysis provides novel insights on the hormonal regulation of postharvest apples under cold storage
No full textPostharvest storage is a crucial phase during which fruit undergoes ripening and senescence. This study is based on the hypothesis that ethylene-auxin interactions play a significant role in determining apple storage life and quality during the postharvest period. To test this hypothesis, fruit flesh firmness and hormone levels were analyzed alongside transcriptomic changes observed through RNA sequencing. A comprehensive investigation of hormone metabolism-related gene expression across the whole transcriptome was conducted in ‘Golden Delicious’ apples over a six-month storage period to elucidate the molecular mechanisms underlying postharvest ripening and senescence. Understanding changes in the ripening process was facilitated by pretreatment with ethylene, the ethylene inhibitor 1-methylcyclopropene (1-MCP), auxin, and the auxin inhibitor 1-N-naphthylphthalamic acid (NPA) prior to cold storage. The results demonstrated that the auxin inhibitor suppressed ethylene production along with auxin levels, while the ethylene inhibitor suppressed auxin levels together with ethylene production throughout all storage periods. Findings also revealed that ethylene and auxin hormones regulate key metabolic processes associated with apple ripening during storage. Additionally, many transcriptional regulatory genes involved in hormone signaling and metabolism, such as AIL5, ABI3, AP2, ERF-011, NAC, RAP210, and REVEILLE, exhibited high activity during storage. Furthermore, this study revealed the high expression levels of ABC transporter and LRR receptor protein kinase for the first time in apples under storage conditions. These findings provide deeper insights into the physiological and molecular changes occurring in climacteric fruit during postharvest storage
On the effect of fluid temperature in hydrodynamic cavitation on a chip reactors
No full textThis study presents an experimental investigation on the effects of the fluid temperature on hydrodynamic cavitation (HC) inside microfluidic devices (HC reactors) with multiple parallel microchannels. Three different reactors featuring microchannel configurations with hydraulic diameters of 89, 66, and 48 micrometers including 9, 21, and 37 microchannels respectively, were fabricated using the semiconductor-based microfabrication techniques. The microchannels have side wall roughness elements with a length of one-third of the entire microchannel length and a height of one-tenth of the hydraulic diameter. The fabricated HC reactors enable the investigation of cavitating flows under different thermophysical conditions at operating pressures ranging from 1.7 to 4.1 MPa and fluid temperatures at 23 °C, 33 °C, and 43 °C, and allow the observation of different cavitating flow morphologies, e.g., sheet, shear, and cloud cavities. According to the results, an increase in the temperature by 10 °C significantly raised the cavitation intensity. Furthermore, the scale effects amplify the effect of the temperature changes. Accordingly, the effect of the temperature is more dominant on the microscale compared to macroscale. An increase in the fluid temperature from 23 °C to 33 °C can double the cavitation penetration length in some microchannels within Reactor 1 at an upstream pressure of 3 MPa. The average penetration length at the extension region also increases (by approximately 70 % for Reactor 1, 50 % for Reactor 2, and 35 % for Reactor 3) upon change in the fluid temperature. The change in the cavitation intensity was larger for the temperature increase from 23 °C to 33 °C than for the increase from 33 °C to 43 °C which emphasizes the increasing dominance of thermal effects with temperature. This study offers understanding how a change in thermal properties influences HC at the microscale. The findings of this study can be utilized for scaling efforts in various applications relying on cavitation such as water treatment, microreactors, nanomaterial synthesis, and micro mixing
Privacy-preserving machine learning (PPML) inference for clinically actionable models
No full textMachine learning (ML) refers to algorithms (often models) that are learned directly from data, germane to past experience. As algorithms have constantly been evolving with the exponential increase of computing power and vastly generated data, privacy of algorithms as well as of data becomes extremely important due to regulations and IP rights. Therefore, it is vital to address privacy and security concerns of both data and model together with other performance metrics when commercializing machine learning models. Our aim is to show that privacy-preserving machine learning inference methods can safeguard the intellectual property of models and prevent plaintext models from disclosing information about the sensitive data employed in training these ML models. Additionally, these methods protect the confidentiality of model users' sensitive patient data. We accomplish this by performing a security analysis to determine an appropriate query limit for each user, using the European Spine Study Group's (ESSG) adult spinal deformity dataset. We implement a privacy-preserving tree-based machine learning inference and run two security scenarios (scenario A and scenario B) containing four parts with progressively increasing the number of synthetic data points, which are used to enhance the accuracy of the attacker's substitute model. A target model is generated with particular operation site(s) in each scenario, and substitute models are built with nine-time threefold cross-validation using the XGBoost algorithm with the remaining sites' data to assess the security of the target model. First, we create box plots of the test sets' accuracy, sensitivity, precision, and F-score metrics to compare the substitute models' performance with the target model. Second, we compare the gain values of the target and substitute models' features. Third, we provide an in-depth analysis to check the inclusion of target model split points in substitute models with a heatmap. Finally, we compare the outputs of public and privacy-preserving models and report intermediate timing results. The privacy-preserving XGBoost model results are identical to the original plaintext model in the aforementioned two scenarios in terms of prediction accuracy. The differences between performance metrics of best-performing substitute models and target models are 0.27, 0.18, 0.25, 0.26 for scenario A, and 0.04, 0, 0.04, and 0.03 for scenario B for accuracy, sensitivity, precision, and F-score, respectively. The differences between target model accuracy and the mean accuracy values of models in each scenario on the substitute models' test dataset are 0.38 for scenario A and 0.14 for scenario B. Based on our findings, we conclude that machine learning models (i.e., our target models) may contribute to the advancement in the field of application where they are deployed. Ensuring the security of both the model and the user data enables the protection of the intellectual property of ML models, preventing the leakage of sensitive information used in training and model users' data.INDEX TERMS Homomorphic encryption, privacy-preserving machine learning, XGBoost
Microfluidic chip-assisted separation process and post-chip microalgae cultivation for carotenoid production
No full textIn many fields of biotechnology, pure microalgae cultures isolated from mixed cultures that exist in nature are needed as raw material sources for the production of high-quality products such as nutraceuticals, cosmetics and biofuels. Regarding the isolation of microalgae, microfluidic systems have gained popularity in recent years due to their low energy and chemical requirements for rapid and effective separation. In this study, optimum flow rates were determined using spiral microfluidics for the separation of microalgae from bacteria, followed by the cultivation of separated microalgae. Then the microalgae obtained in the green phase were subjected to nutrient stress to induce carotenoid production. Carotenoids were extracted after 30-day cultivation, and characterization analyses were performed. Subsequently, the SuperPro Designer® software was used to determine the potential for large-scale carotenoid production from Chlorella minutissima. The experiments showed that the fabricated microfluidic system achieved a separation yield and purity of 84.9% and 93.8%, respectively. Furthermore, a 2.5-fold increase in growth rate and carbohydrate and an approximately 1.3-fold increase in protein, lipid, and pigment contents were observed in the post-chip culture. Additionally, a 170% increase in carotenoids was observed within 20 days after induction with nutrient stress. Also, it was shown that microalgal carotenoids could be produced in large scale from C. minutissima by recultivating post-chip microalgae and subjecting them to nutrient stress. This study considered multiple flow rates in microchannels designed to separate microalgae from bacteria and carotenoid production from sorted microalgae for the first time
You will be defeated by a tripod and a camera: Sedat Peker and the antihero narrative in contemporary politics
No full textIn May and June of 2021, a series of YouTube videos posted by Sedat Peker, a Turkish crime boss, disclosed inside information implicating senior government officials and other public figures in major corruption scandals and crimes. Peker quickly gained popularity and became for the opposition a symbol of the impending fall of the Erdoğan regime. Based on a systematic analysis of these videos and the public debate they engendered, this article argues that the efficacy of Peker’s political campaign depended as much on the stylistic elements and cultural references of his performances as on the grave nature of his allegations about public officials. By showing how the antihero narrative—a genre ubiquitous in contemporary popular culture—is put to use in political performances, the study fills an important gap in narrative genre analysis in cultural sociology
Divisibility of orders of reductions of elliptic curves
No full textLet E be an elliptic curve defined over Q and E˜p denote the reduction of E modulo a prime p of good reduction for E. The divisibility of |E˜p(Fp)| by an integer m≥2 for a set of primes p of density 1 is determined by the torsion subgroups of elliptic curves that are Q-isogenous to E. In this work, we give explicit families of elliptic curves E over Q together with integers mE such that the congruence class of |E˜p(Fp)| modulo mE can be computed explicitly. In addition, we can estimate the density of primes p for which each congruence class occurs. These include elliptic curves over Q whose torsion grows over a quadratic field K where mE is determined by the K-torsion subgroups in the Q-isogeny class of E. We also exhibit elliptic curves over Q(t) for which the orders of the reductions of every smooth fiber modulo primes of positive density strictly less than 1 are divisible by given small integers
When voting is not enough: the relationship between ideological incongruence, party attachment, and protest behavior
No full textThis study categorizes political participation into voting and protesting to highlight how these actions can complement each other in addressing issues of political representation—rather than viewing protests as a substitute for voting. It argues that voters, being more engaged in the political process, are more likely than non-voters to protest in response to ideological incongruence with the government. While electoral participation predicts protesting as a reaction to such incongruence, voting does not always reflect a strong concern for aligning one's preferences with government positions, especially among individuals without party attachments. To account for this variation, the study distinguishes between voters with and without party affiliations, showing that the likelihood of protesting depends on party attachment and the degree of ideological incongruence. Drawing on data from the European Social Survey (2012–2018), covering 41 country-year observations from Western European democracies, and government positions from the Chapel Hill Expert Survey, the findings reveal that ideological incongruence significantly increases the likelihood of protesting as a complement to voting—particularly among individuals who feel close to a party