Systematic Set Research Articles

Child and adolescent social withdrawal predict adult psychosocial adjustment: A meta-analysis

This systematic review and set of five meta-analyses synthesized the results of prospective longitudinal publications on childhood and/or adolescent social withdrawal as a predictor of adult psychosocial adjustment. Meta-analyses were conducted with results for five adult outcomes from 31 publications derived from 14 longitudinal samples and a combined sample size of 19,806 adults (50% women, M = 38.88 years, 83% White) with childhood and/or adolescent ( ≤ 16 years) histories of social withdrawal and their offspring (N = 175). Dependency among publications derived from the same longitudinal samples was explicitly modeled in meta-analyses with clustering. Meta-analytic results support childhood and/or adolescent social withdrawal as a medium-sized risk factor for adult social anxiety and intergenerational difficulties in mothers and their offspring (both p < 0.0001); a small-size risk factor for delayed adult developmental milestones (p < 0.05), adult social withdrawal (p < 0.0001), other anxiety (p < 0.05), and depression (p < 0.01); and a small-size protective factor against adult substance use (p < 0.01). However, meta-analytic results did not support childhood and/or adolescent social withdrawal as a predictor of physical health, likely due to the heterogeneous nature of the investigated health outcomes. Consistent with a Developmental Science Model, results are interpreted as supporting interpersonal mechanisms (missing out, interpersonal stress, and poor relationship quality) and developmental cascades (cross domain-influences) in socially withdrawn children's life-course development. Because evidence for intergenerational difficulties was based on a single longitudinal sample, confidence in intergenerational effects would be increased by replication in other samples. Heterogeneity among effect sizes included in most meta-analyses suggests that the relation between childhood and/or adolescent social withdrawal and adult outcomes is likely to be moderated by other factors. Future directions in this area of research are discussed.

Bridging human rights and social work education: the triple mandate in Austrian and Australian teaching contexts

ABSTRACT This article explores social work’s mandates, delineating the profession’s obligations across three key domains: the client-centric mandate, the state and its agency-driven regulatory and policy mandate and the mandate grounded in the profession’s scientific and ethical standards, including the commitment to human rights—social works triple mandate. Drawing on the author’s experience as a senior lecturer in Austria and Australia, the analysis highlights how the socio-political environments and educational frameworks can shape social work education. The application of the triple mandate is illustrated through a systematic set of W-questions to identify different dimensions of social problems within a broader systemic framework. This approach, grounded in scientific realism—which holds that reality exists independently of our perceptions and aligns with emergent systemism by scientifically examining social interactions to explain complex social systems—equips emerging social workers with the analytical and practical skills to transform private troubles into public issues. A scenario where a school student experiences alienation, leading to absenteeism, exemplifies the connection between theory and action. The discussion concludes by asserting that integrating science-based social work practices with ethical principles empowers social workers to navigate complex professional challenges and strengthens their commitment to human rights and social justice.

Exploring Ion Polarizabilities and Their Correlation with van der Waals Radii: A Theoretical Investigation.

Polarizability (α) is a fundamental property which measures the tendency of the electron cloud of an atom, ion, or molecule to be distorted by electric field. Polarizability contributes to important physical properties such as molecular interactions or dielectric constants; thus, it is essential to have accurate polarizabilities in molecular simulations. However, it remains a challenge to develop polarizable force fields (FFs) for ions in computational chemistry. In particular, a comprehensive set of polarizabilities for ions has not been derived. Herein, we derived a systematic set of polarizabilities for atoms and ions across the periodic table based on high-level quantum mechanics calculations. These values have excellent agreement with experimental data. Furthermore, we examined the relationship between the obtained polarizabilities and the van der Waals (VDW) radii (RVDW) that we previously determined (J. Chem. Theory Comput., 2023, 19, 2064). Two relationships, RVDW ∝ α1/7 and RVDW ∝ α1/3, proposed in previous studies were examined in the present work. Our results indicated the former relationship, which was derived based on the quantum harmonic oscillator model, prevails for atoms and cations, but neither relationship provides a satisfactory fit for anions. This is consistent with the tight-binding nature of the electrons in atoms and cations, while it is more challenging to quantify the polarizabilities of anions because of their more dispersed electron clouds. Moreover, we compared different approaches to determine the dispersion coefficients, including the London equation, Slater-Kirkwood equation, symmetry-adapted perturbation theory (SAPT) calculations, and time-dependent density functional theory method, along with the approach based on VDW constants. Our results indicated that although different approaches predict deviated magnitudes for the dispersion coefficients, their predictions are highly correlated, implying that each of these approaches can be used to evaluate dispersion interactions after proper scaling. Finally, we have developed a parametrization strategy for the 12-6-4 model based on the obtained insights. We specifically compared the performance of the 12-6-4 model with SAPT and SobEDA analyses to model interactions involving Na+/Mg2+ and various ligands containing He, Ne, Ar, H2O, NH3, [H2PO4]-, and [HPO4]2-. Our results demonstrate that the 12-6-4 parameters effectively reproduce both the total interaction energy and the individual energy components (electrostatics, exchange-repulsion, dispersion, and induction), highlighting the physical robustness of the 12-6-4 model and the effectiveness of our parametrization approach. This study has significant implications for advancing the development of next-generation ion models and polarizable FFs.

Quantum Transfer Learning with Adversarial Robustness for Classification of High‐Resolution Image Datasets

AbstractThe application of quantum machine learning to large‐scale high‐resolution image datasets is not yet possible due to the limited number of qubits and relatively high level of noise in the current generation of quantum devices. In this work, this challenge is addressed by proposing a quantum transfer learning (QTL) architecture that integrates quantum variational circuits with a classical machine learning network pre‐trained on ImageNet dataset. Through a systematic set of simulations over a variety of image datasets such as Ants & Bees, CIFAR‐10, and Road Sign Detection, the superior performance of the QTL approach over classical and quantum machine learning without involving transfer learning is demonstrated. Furthermore, the adversarial robustness of QTL architecture with and without adversarial training is evaluated, confirming that our QTL method is adversarially robust against data manipulation attacks and outperforms classical methods.

Prospectively identifying risks and controls for advanced brain-computer interfaces: A Networked Hazard Analysis and Risk Management System (Net-HARMS) approach

The introduction of advanced digital technologies continues to increase system complexity and introduce risks, which must be proactively identified and managed to support system resilience. Brain-computer interfaces (BCIs) are one such technology; however, the risks arising from broad societal use of the technology have yet to be identified and controlled. This study applied a structured systems thinking-based risk assessment method to prospectively identify risks and risk controls for a hypothetical future BCI system lifecycle. The application of the Networked Hazard Analysis and Risk Management System (Net-HARMS) method identified over 800 risks throughout the BCI system lifecycle, from BCI development and regulation through to BCI use, maintenance, and decommissioning. High-criticality risk themes include the implantation and degradation of unsafe BCIs, unsolicited brain stimulation, incorrect signals being sent to safety-critical technologies, and insufficiently supported BCI users. Over 600 risk controls were identified that could be implemented to support system safety and performance resilience. Overall, many highly-impactful BCI system safety and performance risks may arise throughout the BCI system lifecycle and will require collaborative efforts from a wide range of BCI stakeholders to adequately control. Whilst some of the identified controls are practical, work is required to develop a more systematic set of controls to best support the design of a resilient sociotechnical BCI system.

Creation of a Systematic Interdental Brush Set Based on the Passage Hole Diameter (PHD) - An In-Vitro Study.

This study aimed to develop a systematic interdental brush set with size distribution based on the passage hole diameter (PHD), addressing existing gaps in size selection criteria for effective interdental cleaning. In the first step, an interdental brush set that ascends stepwise according to the PHD value was envisioned. The study was divided into three phases: (i) in-vitro determination of PHD values of a currently existing assortment on the market by 13 calibrated dental professionals, (ii) in-vitro assessment of forces during insertion, and (iii) creation and evaluation of new prototypes for missing or non-matching PHD sizes. Intra- and inter-rater reliability, assessed with the intraclass correlation coefficient (ICC), as well as insertion forces and PHD sizes at all stages were reported. In the existing range, three interdental brushes fitting the desired PHD sizes were initially identified. Mean insertion forces between 0.3 and 1.7 N were documented based on raters' PHD choices. Two additional rounds of measurements with prototypes adapted in diameter and shape were necessary, particularly for PHD values of 1.4, 2.3 and 2.6. High intra- and inter-rater reliability was observed throughout the study (ICC > 0.95), ensuring consistent evaluations. After three rounds of assessments, a prototype was successfully identified for each targeted PHD value in the systematised set, showcasing reliable sizing and insertion forces. Using a structured approach, a comprehensive interdental brush set was developed with reliable PHD sizing and moderate insertion forces. The verification of size reliability through measurements by dentists represents a novelty in development and underlines the importance of accurate brush size selection for optimal biofilm control. Whether a systematic set based on the PHD value offers added value for clinical practice, and at what intervals, must be demonstrated in further studies.

Sustainable design: Circular innovation design method under process reengineering

The theory of sustainable business process reengineering has been widely applied in various disciplines and has achieved outstanding results. The theory is used to the research of product innovation design method in this work, and the entire process of product innovation design method is reshaped, bringing new development and new direction for product innovation design. Redesign processes in line with societal trends and in a sustainable direction. Furthermore, it may effectively address the inadequacies of conventional design methodologies during the application process. Then, increase corporate efficiency in order to accomplish significant improvements in enterprise cost, quality, service, and speed. The study applies the systematic induction method, research analysis method, and other comprehensive research methods to analyze and study the existing design process and method, as well as excavate the shortcomings and limitations that exist in the process's application of the existing design method. Based on the BPR theory, the sustainable innovation design method for full chain products is divided into five design processes: scenario implantation, requirement extraction, functional determination, structural optimization, formal innovation, and material selection. In addition, the feasibility and accuracy of this method are verified through lifesaving equipment cases. Secondly, three principles for sustainable product innovation design were proposed. On the one hand, products made by designers and college students can truly meet customer needs, generate disruptive innovative designs, and improve the market competitiveness of industrial products. On the other hand, design is no longer a single stage, but a complete, systematic, and comprehensive set of design processes aimed at improving design efficiency and achieving sustainable product development.

The effect of hydrogen co-injection on the microstructure of triple ion irradiated F82H

The reduced activation ferritic/martensitic steel F82H-IEA was studied through a systematic set of dual (Fe2++He2+) and triple (Fe2++He2++H+) ion irradiations to determine the effect of hydrogen co-injection with helium and radiation damage on the irradiated microstructure and in particular, cavity evolution. Irradiations were conducted in four distinct permutations from a set of nominal irradiation parameters of 50 dpa, 1 × 10–3 dpa/s, 500 °C, and 40/10 appm/dpa of H/He or 10 appm/dpa of He. A temperature series of dual and triple ions ranging from 400 to 600 °C was conducted where swelling values of 1.3–2.4x were obtained with the co-injection of hydrogen. A damage level (50 to 150 dpa) and damage rate (2.5 × 10–4 to 2.5 × 10–3 dpa/s) series were also conducted where hydrogen was again observed to cause a ∼1.2–1.8x increase in swelling in triple ion irradiation versus dual ions. The effect of hydrogen was also observed to increase the overall steady state swelling rate from 0.02%/dpa in dual ions to 0.034%/dpa under triple ions at 500 °C by 150 dpa. A final series of triple ion experiments was conducted at 450 °C and 500 °C at 80 appm/dpa of H where swelling was suppressed by 50% compared to the dual ion irradiated case due to over-nucleation of small bubbles. The effect of hydrogen on bubble nucleation was to stabilize higher densities of smaller helium bubbles possibly through increasing nucleation rates and reduction of the stable bubble radius. The effect on swelling was in the promotion of higher densities of larger voids experiencing bias-driven growth. Hydrogen was shown to have a moderate influence on the nucleation and growth of dislocation loops, although these effects appear to be convoluted by the changes in cavity microstructure dominating sink strength across conditions. Hydrogen co-injection was also loosely correlated with enhanced dissolution of M23C6 precipitates across temperature and damage level regimes.

A Comprehensive Business Location Choice Model Leveraging Machine Learning in Systematic Choice Set

This study develops a comprehensive two-stage location choice framework for business establishments as part of a goods movements modeling. This study aims to formulate a systematic methodology for investigating the location choice of business establishments within Halifax Regional Municipality. This study presents a novel approach that leverages machine learning techniques to generate a systematic choice set, thereby improving the representation of realistic and reasonable location alternatives. Info Canada Business Establishments dataset 2022 is employed to achieve the aim of this study. Combining an unsupervised machine learning technique with the mixed multinomial logit model facilitates a data-driven approach to enhance the precision and robustness of business establishment location choice models. This approach possesses the potential to unveil latent patterns and heterogeneity among potential choice alternatives that may remain obscured when utilizing a conventional multinomial logit model. This thorough analysis offers robust insights into the factors influencing the location choice of business establishments. The findings obtained from this comprehensive study suggest that wholesalers prioritize proximity to highways and positions within business parks for their operations while avoiding higher population density and central business district proximity. Transportation businesses seek larger sites and locations near highways, favoring clustering with related transport companies and valuing accessibility and cost-effectiveness over proximity to business parks or rural settings. The findings of this study could provide valuable insights for commercial vehicle and goods movement modeling, business location strategies, and policymaking concerning sustainable urban development.

Was priority setting considered in COVID-19 response planning? A global comparative analysis

BackgroundThe COVID-19 pandemic forced governments across the world to consider how to prioritize resource allocation. Most countries produced pandemic preparedness plans that guide and coordinate healthcare, including how to allocate scarce resources such as ventilators, human resources, and therapeutics. The objective of this study was to compare and contrast the extent to which established parameters for effective priority setting (PS) were incorporated into COVID-19 pandemic response planning in several countries around the world. MethodsWe used the Kapriri and Martin framework for effective priority setting and performed a quantitative descriptive analysis to explore whether and how countries’ type of health system, political, and economic contexts impacted the inclusion of those parameters in their COVID-19 pandemic plans. We analyzed 86 country plans across six regions of the World Health Organization. ResultsThe countries sampled represent 40% of nations in AFRO, 54.5% of EMRO, 45% of EURO, 46% of PAHO, 64% of SEARO, and 41% of WPRO. They also represent 39% of all HICs in the world, 39% of Upper-Middle, 54% of Lower-Middle, and 48% of LICs. No pattern in attention to parameters of PS emerged by WHO region or country income levels. The parameters: evidence of political will, stakeholder participation, and use of scientific evidence/ adoption of WHO recommendations were each found in over 80% of plans. We identified a description of a specific PS process in 7% of the plans; explicit criteria for PS in 36.5%; inclusion of publicity strategies in 65%; mention of mechanisms for appealing decisions or implementing procedures to improve internal accountability and reduce corruption in 20%; explicit reference to public values in 15%; and a description of means for enhancing compliance with the decisions in 5%. ConclusionThe findings provide a basis for policymakers to reflect on their prioritization plans and identify areas that need to be strengthened. Overall, there is little consideration for explicit prioritization processes and tools and restricted attention to equity considerations; this may be a starting point for policymakers interested in improving future preparedness and response planning. Although the study focused on the COVID-19 pandemic, priority setting remains one of the policymakers’ most prominent challenges. Policymakers should consider integrating systematic priority setting in their routine decision-making processes.

STARDUST: a pipeline for the unbiased analysis of astrocyte regional calcium dynamics.

Calcium imaging has become a popular way to probe astrocyte activity, but few analysis methods holistically capture discrete calcium signals that occur across the astrocyte domain. Here, we introduce STARDUST, a pipeline for the Spatio-Temporal Analysis of Regional Dynamics & Unbiased Sorting of Transients from fluorescence recordings of astrocytes, and provide step-by-step guidelines. STARDUST yields fluorescence time-series from data-defined regions of activity and performs systematic signal detection and feature extraction, enabling the in-depth and unbiased study of astrocyte calcium signals.

Flipped Project-Based Learning Model in Creative Writing Class: How Do Students Need It?

Student needs for each course are different. Implementations that do not meet the needs will cause problems in the learning process. This study aims to analyze the characteristics of materials to be used in creative writing classes, especially while learning opinion writing that meets the students' needs of learning materials. This research is a quantitative descriptive study. Using purposive sampling technique, 38 of all students of the PGRI University of West Sumatra in the Indonesian Language and Literature Education Study Program, participated in this study. The students were asked to respond to an online questionnaire investigating their situation in the creative writing class, their needs and difficulties in learning materials about opinion writing as one of subtopics in the creative writing course. This research provides insights to design a Flipped Project Based Learning model using an e-learning platform. The results revealed that with the conventional learning, some students were less motivated and creative, so it is necessary to provide learning materials that can encourage all students' active participation and writing creativity without exception . Besides, the students need a complete and systematic set of learning materials about the concept of opinion writing that allows them to customize the topics and ideas for writing opinions, along with lecturer guidance in understanding the concept of writing the opinions. Additionally, the materials should be able to help them deal with their difficulties in determining ideas and the title of the opinion essay.

Structure-Activity Relationships, Deuteration, and Fluorination of Synthetic Cannabinoid Receptor Agonists Related to AKB48, 5F-AKB-48, and AFUBIATA.

Synthetic cannabinoid receptor agonists (SCRAs) are a growing class of new psychoactive substances (NPS) commonly derived from an N-alkylated indole, indazole, or 7-azaindole scaffold. Diversification of this core (at the 3-position) with amide-linked pendant amino acid groups and modular N-alkylation (of the indole/indazole/7-azaindole core) ensures that novel SCRAs continue to enter the illicit drug market rapidly. In response to the large number of SCRAs that have been detected, pharmacological evaluation of this NPS class has become increasingly common. Adamantane-derived SCRAs have consistently appeared throughout the market since 2011, and as such, a systematic set of these derivatives was synthesized and pharmacologically evaluated. Deuterated and fluorinated adamantane derivatives were prepared to evaluate typical hydrogen bioisosteres, as well as evaluation of the newly detected AFUBIATA.

The effects of immersive virtual reality field trips upon student academic achievement, cognitive load, and multimodal presence in a social studies educational context

AbstractThere is increasing educational interest in immersive virtual reality (IVR) applications which aid student learning and performance. However, few empirical studies have investigated the potential for implementing the technology in middle-school social studies classrooms. This study employed a quasi-experimental approach to address this issue, using pre- and post-test evaluations to measure academic achievement, and questionnaires to examine cognitive load and sense-of-presence. 48 seventh-grade students participated, split evenly between experimental and control groups. The experimental group received a systematic set of IVR-based social studies lessons via Head-Mounted Displays, while the control group covered identical content conventionally. Experimental group participants attained higher academic achievement with lower cognitive loading than control group students. The experimental group also experienced high levels of multimodal presence (physical, social, and self). This study yielded empirical evidence demonstrating the potential benefits which IVR offers social studies education. Furthermore, it provides an example for how effective, IVR-based social studies lessons can be developed.

IJCM_258A: Perceptions regarding mid-day meal programme among parents of government school children in rural field practice area of a government medical college a cross sectional study.

Background: Mid - Day Meal Scheme (MDMS) renamed as PM POSHAN in 2021 is aiding 11.80 crore children studying in 11.20 lakhs schools across the country making it the largest school feeding programme in the world. This study was intended to know the opinion of parents of children going to government schools regarding mid - day meal. Objectives: 1. To study the perceptions of parents regarding Mid -Day Meal Scheme. 2. To identify the barriers for non-consumption of Mid - day meals. Methodology: Study Design Cross - sectional study Sampling Systematic Random Sampling Study setting “Rural Field Practice Area of a Government medical college. Study Period November - December 2023 Inclusion criteria Parents and Guardians who gave written informed consent. Exclusion criteria Parents who could not respond due to mental problems. Ethical Prior ethical approval was taken from Institutional Ethics Committee. Data collection and analysis data collection was done using pre-designed semi structured questionnaire and analyzed using Excel and SPSS software. Results: Mean age of the respondents (parent) was 33±7SD. Majority (72.9%) of the respondents were mothers. 59.4% of parents perceived that quality of MDM was good. It was found that overall satisfaction among parents regarding MDM was 65%. More than two thirds (67.5%) of parents felt that MDM has improved their childs school performance. Conclusion: Most of the parents were satisfied about the quality of mid - day meal and few parents agreed that MDM has encouraged parents to send their children to school. Most of the parents agreed that MDM is beneficial and should be continued

Powerful or Powerless? Women’s Power Levels in Contemporary Chinese Films

This article aims to achieve an experiential study of cinematic representations of females in Chinese films through quantitative narrative analysis. Applied to a census of 360 Chinese films across various genres produced across 18 years (2001–2018) systematically selected on Mtime, we ask to what extent female characters in Chinese films are empowered? How is their power exercised? And what socio-cultural implications can be detected from the cinematic representations of women in the contemporary Chinese gender discourse? We aim to fill in the gap in Chinese cinema studies in which most scholarships focused on pre-2000 works, adopted qualitative textual and narrative analysis to interpret the representations of women in a particular genre or in typical cases, leaving the quantitative approach, particularly focusing on the post-2000 films, all but absent. We develop a systematic set of typologies, including 4 major power-level categories (power-over, power-to, power-with, and no-power) and 12 deuterogenic ones, which can be applied for future research on Chinese film and media studies. While women’s career success has been articulated with empowerment, independence, subjectivity, and ambition in the neoliberal rhetoric, our research reflects a more intricate relationship between cultural representations of women and power in contemporary Chinese films.

Finite-Time Fault-Tolerant Formation Control for Distributed Multi-Vehicle Networks With Bearing Measurements

This paper addresses a bearing-only formation tracking problem in robotic networks by considering exogenous disturbances and actuator faults. In contrast to traditional position-based coordination strategies, the bearing-only coordinated movements of the unmanned vehicles only rely on the neighboring bearing information. This feature can be utilized to reduce the sensing requirements in the hardware implementation. A gradient-descent protocol is first developed to achieve the desired coordination within a prespecified settling time, where the unknown disturbances are considered in the vehicle dynamics, then the bound of formation tracking error is guaranteed by the Lyapunov approach. In case of damage to the actuators (e.g., motors) in some of the vehicles during the task, fault-tolerant analysis of the proposed controller is provided to ensure the success of the task in extreme environments. Furthermore, the proposed bearing-based method is extended to deal with general linear systems, which can be applied to a wider range of robotic platforms. Finally, numerical simulations and lab-based experiments using unmanned ground vehicles are conducted to validate the effectiveness of the proposed strategy. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The aim of this paper is to develop and design a practical bearing-only formation control approach for multi-vehicle systems. Many real-world complex tasks can be solved by multiple unmanned aerial and ground vehicles being connected by a communication network. This paper has proposed a formation tracking scheme for networked multi-vehicle systems that only relies on the relative bearing information of the neighboring vehicles. Closed-loop stability of the scheme and finite-time convergence of the tracking error have been established using the Lyapunov stability approach. The proposed method ensures the robustness and fault-tolerance of the multi-vehicle system against hardware faults or exogenous disturbances. A systematic set of guidelines on how to apply the proposed strategy in practice is also provided for the control practitioners in the form of an algorithm. In order to demonstrate the feasibility and usefulness of the proposed coordination scheme, numerical simulations and lab-based hardware experiments were conducted. Potential applications of the proposed scheme include search and rescue, security surveillance and cooperative exploration.

The Problem of Defining Insurance of Business and Financial Risks in Russian Legislation

The development of Russian insurance legislation is associated with the presence of certain differences in the legal regulation of the insurance business; in particular, there is the problem of classifying certain types of insurance: business insurance and financial risk insurance. The purpose of the study is to consider sequentially the main stages of the development of insurance legislation in terms of insurance of business and financial risks, which would allow us to identify, on the one hand, the reasons for changes in insurance legislation, and, on the other hand, to form the authors’ own standpoints on this issue and draw appropriate conclusions. The article examines the changes made to national insurance legislation over the course of a quarter of a century, and identifies contradictions and differences in the definitions of insurance of business and financial risks. The authors have drawn the conclusion that there is a global cause of the observed phenomena, which is the absence in our country of a single codified normative legal act regulating insurance relationships — the Insurance Code. According to the authors, the development and adoption of such a systematic set of insurance legislation would be the most important step towards solving the problem of classifying types of insurance, in particular business risk insurance and financial risk insurance.

Interface Amorphization Controls Maximum Wear Resistance of Multinanolayer DLC/WC Coatings.

Multilayer coatings offer significant advantages in protecting materials' surfaces by shielding the underlying materials hierarchically from damage and wear. The layering morphology and structure of multilayer coatings directly affect their wear resistance capacity. Using a systematic set of experiments and molecular dynamics (MD) simulations, we studied the effect of layering thickness on the macroscale wear response of DLC/WC multinanolayer coatings. Our study revealed the existence of a critical bilayer thickness where maximum scratch hardness and wear resistance can be achieved. Our large-scale MD simulations showed that reducing the WC layer thickness to a certain limit increases the scratch hardness due to the confinement of dislocation motion. However, when the thickness of the WC layers falls below 2 nm, the deformation mechanism transitions from the interface-induced dislocation confinement to the interface-mediated amorphization of WC layers, reducing the scratch hardness of the coating. This finding offers a procedure for optimizing the macroscale wear performance of multinanolayer coatings.

Effect of grain boundary on scratch behavior of polycrystalline copper

The anisotropy in the elastoplastic response of crystalline solids influences substantially their scratch resistance at the microscale. While grain boundaries typically act as obstacles to the motion of dislocations at the grain level, the scratch behavior in the vicinity of the grain boundary is influenced by other factors such as crystallographic orientation and pile-up topography. We performed a systematic set of nano-scratch simulations using the mechanism-based strain gradient crystal plasticity to study the evolution of scratch force and depth near grain boundaries. To validate our model, we conducted a nano-scratch test on a polycrystalline copper sample and compared the scratch depth profile for a specific grain boundary with the simulated result, where a good qualitative agreement was achieved. Our simulations showed that the scratch depth, force, and hardness vary between the corresponding values for the individual constitutive grains, and the variation decreases by reducing the grain size. Additionally, we analyzed the scratch response in terms of the pile-up topography and subsurface stresses and distinguished different regimes when the indenter approaches and scratches across the boundary. Our findings offer a new direction to optimize the scratch resistance of polycrystalline metals by tailoring the size and orientation of grains near the surface. Additionally, it introduces scratching as a robust material characterization method.