Array Of Obstacles Research Articles

The experiences of individuals in maintaining a long-distance relationship through social media

This qualitative study explores the dynamics of long-distance romantic relationships (LDRRs) in the digital age. Long-distance relationships (LDRs) have emerged as a testament to the enduring strength of human affection in the face of spatial constraints. However, the dynamics of LDRs in the digital era present a diverse array of emotions, obstacles, and coping mechanisms. The purpose of this study is to understand the distinctive experiences of how social media has had a positive influence on the communication and relationship satisfaction between partners who have experienced long distance. The research, conducted through qualitative methods, involved 8 college students, predominantly females, offering insights into their experiences in current LDRs. Through semi-structured interviews with eight participants aged 18 to 24 in LDRRs, themes emerged regarding social media usage, coping strategies for emotional challenges, insecurities and communication, and the influence of family environments. The theme underscores how digital tools serve as essential resources for maintaining emotional intimacy and strengthening the relationship despite the challenges of distance. It also highlights the importance of familial support, privacy management, and individual resilience in sustaining intimate connections across geographical distances. The findings reveal that social media platforms such as WhatsApp and Instagram are integral to communication in LDRRs, with participants emphasising the importance of voice and video calls for maintaining intimacy. Coping with emotional challenges, including insecurities and feelings of disconnection, involves active communication, transparency, reassurance, and planning activities together. Family environments play a significant role in shaping communication dynamics, with participants navigating constraints on privacy and openness based on familial support or constraints. Overall, this study underscores the vital role of social media in sustaining emotional intimacy and connection in LDRRs. Understanding how individuals utilise social media and cope with challenges can inform interventions to support healthy, fulfilling relationships in the digital age.

Barriers to equitable greening in urban environmental policies

ABSTRACT Histories of racist and classist land use decision-making have resulted in environmental disparities across lines of race and income in many U.S. cities. To redress this, many municipal governments are adopting urban greening initiatives that aim to provide public health benefits and bolster climate resilience in underserved communities. Unfortunately, increasing the quantity of green space in these areas does not necessarily mitigate disparities as environmental quality is just one factor in the broader challenges imposed by legacy land use decision-making. Green development in underserved neighborhoods has the potential to worsen social and economic equity concerns due to the influence of market forces. Employing a mixed-method approach encompassing policy review, spatial exploration, and qualitative interviews, this research examined the policies that guide urban greening decision-making in Philadelphia, Pennsylvania. Results indicate that Philadelphia faces a complex array of obstacles that inhibit equitable urban greening through four themes: (1) perceptions of agency responsibilities, (2) approaches to stakeholder engagement, (3) patterns of disinvestment and maintenance, and (4) project siting decisions. New policies and approaches are recommended to address these obstacles.

How Does the Use of Artificial Intelligence Reflect on Business Administration and Management? A Perspective on Knowledge Production at the Postgraduate Level

Objectives: The extensive adoption of AI applications in many industries raises concerns over their potential to significantly transform employment in various aspects, including job creation, automation, and decision-making procedures. The impact that AI has on employment dynamics presents an array of obstacles and opportunities for the fields of business administration and management. Given all these advancements, the present study conducts a thorough examination of postgraduate theses, recognizing them as a systematic representation of the expanding influence of AI in the fields of business administration and management. Postgraduate research, which entails a thorough academic investigation, provides a crucial perspective for understanding the present condition and future course of AI use in business environments. Through an in-depth examination of postgraduate theses, this research attempts to reveal trends in the application of AI technologies in various organizational contexts. Design/methodology/approach: The 73 master's and doctoral theses used in this study were obtained from the repository of the Council of Higher Education National Thesis Center. The sample spans a range of institutions, demonstrating the diversity and depth of AI research across the academic landscape of management studies. To comprehensively examine and understand the information categories encompassed in these theses, the research utilizes two techniques: document analysis and descriptive content analysis. Document analysis systematically examines the theses as data sources, enabling a thorough investigation of the material that focuses on the identification, assessment, and synthesis of information pertaining to AI in business administration and management. Descriptive content analysis classifies and facilitates a methodical examination of the data. The distribution of theses subjected to document analysis was based on thesis type, universities and sub-disciplines, publication year and language, sample characteristics, methodology, theories, AI application areas, and keywords. Results: The findings show that studies on AI have gained momentum in the last four years, with a high percentage of theses focusing on management, organization, and marketing. The quantitative research method has been the most preferred for postgraduate theses. Additionally, human resource management, machine learning, and artificial neural networks constitute most of the research focus. The data indicates that most master's theses concentrate on human resource management and marketing. The finance and information technology sectors are predominant in terms of industry focus. Practical implications: The findings have the potential to significantly assist practitioners in understanding the ongoing research on AI, enabling them to align their strategic planning with the latest discoveries and approaches in higher education. The prevalence of machine learning and artificial neural networks signifies an inclination towards increasingly complex AI implementations within organizations. Organizations may leverage this understanding to increase innovation, enhance decision-making procedures, and sustain a competitive advantage through the implementation of cutting-edge AI. Furthermore, this study can assist researchers, such as master's and doctoral students, with the topic, research question, data source, data collection tool, and analysis type selection in future studies. Originality/value: The study is expected to provide insights into research focus, scope, and methodology for future research by revealing the current state of AI research in business administration and management domains in Turkey. Through the examination of postgraduate theses, this study not only highlights the increasing academic attention towards AI but also establishes a foundation upon which subsequent research can be built. This study represents an initial effort to gain deeper insights into AI research in Turkey, specifically focusing on knowledge production within universities.

Active nematic ratchet in asymmetric obstacle arrays.

We numerically investigate the effect of an asymmetric periodic obstacle array in a two-dimensional active nematic. We find that activity in conjunction with the asymmetry leads to a ratchet effect or unidirectional flow of the fluid along the asymmetry direction. The directional flow is still present even in the active turbulent phase when the gap between obstacles is sufficiently small. We demonstrate that the dynamics of the topological defects transition from flow mirroring to smectic-like as the gap between obstacles is made smaller, and explain this transition in terms of the pinning of negative winding number defects between obstacles. This also leads to a nonmonotonic ratchet effect magnitude as a function of obstacle size, so that there is an optimal obstacle size for ratcheting at fixed activity.

Wake structure of an array of cylinders in shallow flow

Although there is a range of approaches for classifying the wake structure behind an array of obstacles, these approaches provide inconsistent results across different array systems. This motivates the present study to integrate and reconcile these approaches into one that is consistent across different systems. This new, transferable classification approach is based on the dimensionless flow blockage of the array and the wake stability parameter. To demonstrate this approach, a series of laboratory experiments was conducted to characterise the wake structure behind an array of emergent cylinders across a practically relevant parameter space that has not previously been explored. Two arrays with the same values of flow blockage and wake stability parameters but different sizes display the same wake structure, demonstrating the controlling influence of these two parameters on the wake structure. This approach classifies four different wake structures, which are distinct in that they display differences in instantaneous and time-averaged flow fields, temporal velocity oscillations, shear layer growth and the length of the steady wake region. The dependence of the wake structure on the two parameters is a consequence of (i) the controlling influence of blockage on the fraction of incident flow passing through the array and (ii) the ability of shallowness to suppress wake instabilities and, to a lesser extent, also influence the velocity through the array. This paper provides a predictive framework for the wake structure based on knowledge of the array geometry, and the depth and velocity of incident flow across the entire relevant practical parameter space.

Numerical investigation of bubble dynamics and flow boiling heat transfer in cylindrical micro-pin-fin heat exchangers

Micro-pin-fin evaporators are a promising alternative to multi-microchannel heat sinks for two-phase cooling of high power-density devices. Within pin-fin evaporators, the refrigerant flows through arrays of obstacles in cross-flow and is not restricted by the walls of a channel. The dynamics of bubbles generated upon flow boiling and the associated heat transfer mechanisms are expected to be substantially different from those pertinent to microchannels; however, the fundamental aspects of two-phase flows evolving through micro-pin-fin arrays are still little understood. This article presents a systematic analysis of flow boiling within a micro-pin-fin evaporator, encompassing bubble, thin-film dynamics and heat transfer. The flow is studied by means of numerical simulations, performed using a customised boiling solver in OpenFOAM v2106, which adopts the built-in geometric Volume of Fluid method to capture the liquid–vapour interface dynamics. The numerical model of the evaporator includes in-line arrays of pin-fins of diameter of 50μm and height of 100μm, streamwise pitch of 91.7μm and cross-stream pitch of 150μm. The fluid utilised is refrigerant R236fa at a saturation temperature of 30 °C. The range of operating conditions simulated includes values of mass flux G=500–2000kg/(m2s), heat flux q=200kW/m2, and inlet subcooling ΔTsub=0–5K. This study shows that bubbles nucleated in a pin-fin evaporator tend to travel along the channels formed in between the pin-fin lines. Bubbles grow due to liquid evaporation and elongate in the direction of the flow, leaving thin liquid films that partially cover the pin-fins surface. The main contributions to heat transfer arise from the evaporation of this thin liquid film and from a cross-stream convective motion induced by the bubbles in the gap between the cylinders, which displace the hot fluid otherwise stagnant in the cylinders wakes. When the mass flow rate is increased, bubbles depart earlier from the nucleation sites and grow more slowly, which results in a reduction of the two-phase heat transfer. Higher inlet subcooling yields lower two-phase heat transfer coefficients because condensation becomes important when bubbles depart from the hot pin-fin surfaces and reach highly subcooled regions, thus reducing the two-phase heat transfer.

Mixed debris interaction with obstacle array under extreme flood conditions

Mixed debris interaction with obstacle array under extreme flood conditions

Reversible, irreversible, and mixed regimes for periodically driven disks in random obstacle arrays.

We examine an assembly of repulsive disks interacting with a random obstacle array under a periodic drive and find a transition from reversible to irreversible dynamics as a function of drive amplitude or disk density. At low densities and drives, the system rapidly forms a reversible state where the disks return to their exact positions at the end of each cycle. In contrast, at high amplitudes or high densities, the system enters an irreversible state where the disks exhibit normal diffusion. Between these two regimes, there can be an intermediate irreversible state where most of the system is reversible, but localized irreversible regions are present that are prevented from spreading through the system due to a screening effect from the obstacles. We also find states that we term "combinatorial reversible states" in which the disks return to their original positions after multiple driving cycles. In these states, individual disks exchange positions but form the same configurations during the subcycles of the larger reversible cycle.

Chiral active particles are sensitive reporters to environmental geometry

Chiral active particles (CAPs) are self-propelling particles that break time-reversal symmetry by orbiting or spinning, leading to intriguing behaviors. Here, we examined the dynamics of CAPs moving in 2D lattices of disk obstacles through active Brownian dynamics simulations and granular experiments with grass seeds. We find that the effective diffusivity of the CAPs is sensitive to the structure of the obstacle lattice, a feature absent in achiral active particles. We further studied the transport of CAPs in obstacle arrays under an external field and found a reentrant directional locking effect, which can be used to sort CAPs with different activities. Finally, we demonstrated that parallelogram lattices of obstacles without mirror symmetry can separate clockwise and counter-clockwise CAPs. The mechanisms of the above three novel phenomena are qualitatively explained. As such, our work provides a basis for designing chirality-based tools for single-cell diagnosis and separation, and active particle-based environmental sensors.

Subdiffusion in an array of solid obstacles

More than a decade ago, Goychuk reported on a universal behavior of subdiffusive motion (as described by the generalized Langevin equation) in a one-dimensional bounded periodic potential (Goychuk 2009 Phys. Rev. E 80 046125) where the numerical findings show that the long-time behavior of the mean squared displacement is not influenced by the potential, so that the behavior in the potential, under homogenization, is the same as in its absence. This property may break down if the potential is unbounded. In the present work, we report on the results of simulations of subdiffusion in a two-dimensional (2D) periodic array of solid obstacles (i.e. in an unbounded potential) with different packing fractions. It is revealed that the universal subdiffusive behavior at long times is not influenced by the presence of solid scatterers, whose presence influences the behavior at intermediate times only. This result is discussed as having possible relations to the emerging problem of interpretation of results on trajectories of tracers spreading in the brain’s extracellular space.

Digital Transformation of Small and Medium Sized Enterprises (SMEs): Current Status, Dilemmas, and Strategies

With the rapid advancement of information technology, the digital transformation of SMEs has emerged as a critical topic in the development of the digital economy. The advantages offered by digital technology provide novel opportunities for SME growth. Digital transformation not only serves as a pivotal route for fostering innovation and high-quality development within businesses but also stands as an imperative choice in addressing market competition and uncertainties. However, compared to large corporations, SMEs encounter an array of unique dilemmas and obstacles during their digital transformation journey. These dilemmas frequently include a lack of digital awareness, insufficient funding, weak foundations, and talent shortages. This paper begins by examining the current status of SME digital transformation in terms of exploration phase, geographical distribution, and industry distribution. It then delves deep into the reasons behind the dilemmas faced during the digital transformation of SMEs and proposes a set of countermeasures in response.

Vortex Lattices in Active Nematics with Periodic Obstacle Arrays.

We numerically model a two-dimensional active nematic confined by a periodic array of fixed obstacles. Even in the passive nematic, the appearance of topological defects is unavoidable due to planar anchoring by the obstacle surfaces. We show that a vortex lattice state emerges as activity is increased, and that this lattice may be tuned from "ferromagnetic" to "antiferromagnetic" by varying the gap size between obstacles. We map the rich variety of states exhibited by the system as a function of distance between obstacles and activity, including a pinned defect state, motile defects, the vortex lattice, and active turbulence. We demonstrate that the flows in the active turbulent phase can be tuned by the presence of obstacles, and explore the effects of a frustrated lattice geometry on the vortex lattice phase.

Analysis of the Causes of the Chinese High School Education Burden

In recent years, the education sector has grappled with a pressing issue the phenomenon of "involution". This trend has gained momentum due to the relentless rise in academic pressures faced by students. Scholars and researchers have increasingly turned their attention to unraveling the root causes of educational stress and the intensification of competition within the system. Notably, there has been a remarkable surge in publications addressing educational alleviation, paralleled by a growing body of empirical research in this area. This article delves into the multifaceted challenges associated with educational alleviation, adopting a perspective rooted in basic economic principles, such as the signaling theory and the prisoner's dilemma. It contends that the Chinese education sector confronts a complex array of obstacles. One primary challenge is the scarcity of educational resources, which strains the system's capacity to cater to the diverse needs of its student population. Additionally, a societal bias in evaluating the worth of individuals based solely on academic achievements exacerbates the problem. In conclusion, this article highlights the intricate dynamics at play within the Chinese education industry, shedding light on the intricate interplay of factors that contribute to the persistent issue of involution. It underscores the need for a holistic approach and systemic reforms to mitigate these challenges and promote a more balanced and equitable educational landscape.

PERMEABILITY OF PARTIALLY TO FULLY RANDOMIZED ARRAYS OF SQUARE OBSTACLES: A LATTICE BOLTZMANN APPROACH

Porous media consisting of monodisperse square obstacles were computationally studied using the lattice Boltzmann method in the Darcy regime. Different random arrays of obstacles were generated from the ordered arrays of obstacles using a new algorithm for controlled randomization. The porosity lies in the dilute to moderately dense range of 0.85-0.69. By proper nondimensionalization of the randomization parameter, it was demonstrated that the normalized permeability linearly depends on this parameter within slight randomizations through all porosities. Further randomization breaks the linear dependence, where the normalized permeability undergoes a sharp transition to a plateau at smaller porosities and a continuous transition at larger porosities. The plateau values of the normalized permeability linearly depend on the porosity. Interstitial flow maps show an immediate breakdown of spatial velocity distribution in ordered configurations starting with randomization and manifesting major flow channeling at higher randomizations, which can explain the transition types for permeability.

Flow and clogging of capillary droplets.

Capillary droplets form due to surface tension when two immiscible fluids are mixed. We describe the motion of gravity-driven capillary droplets flowing through narrow constrictions and obstacle arrays in both simulations and experiments. Our new capillary deformable particle model recapitulates the shape and velocity of single oil droplets in water as they pass through narrow constrictions in microfluidic chambers. Using this experimentally validated model, we simulate the flow and clogging of single capillary droplets in narrow channels and obstacle arrays and find several important results. First, the capillary droplet speed profile is nonmonotonic as the droplet exits the narrow orifice, and we can tune the droplet properties so that the speed overshoots the terminal speed far from the constriction. Second, in obstacle arrays, we find that extremely deformable droplets can wrap around obstacles, which leads to decreased average droplet speed in the continuous flow regime and increased probability for clogging in the regime where permanent clogs form. Third, the wrapping mechanism causes the clogging probability in obstacle arrays to become nonmonotonic with surface tension Γ. At large Γ, the droplets are nearly rigid and the clogging probability is large since the droplets can not squeeze through the gaps between obstacles. With decreasing Γ, the clogging probability decreases as the droplets become more deformable. However, in the small-Γ limit, the clogging probability increases since the droplets are extremely deformable and wrap around the obstacles. The results from these studies are important for developing a predictive understanding of capillary droplet flows through complex and confined geometries.

A robust dislocation line tension model considering obstacle strength distribution for yield strength prediction of an Al–Cu–Li alloy

In this study, the yield strength of AA2195 (Al–Cu–Li) alloy as a function of ageing time was determined using a dislocation line tension model. The model simulates the dislocation motion through an array of point obstacles, which represent forest dislocations and semi-coherent precipitates (T1 and θ’). These obstacles were distributed within the simulation environment according to experimentally derived areal densities of the T1 and θ’ precipitates and the forest dislocations. Point obstacles symbolizing T1 and θ’ precipitates were assigned a strength value derived from a log–normal approximation of the size distribution of the precipitates as observed using transmission electron microscopy. A notable agreement between experimental and simulated results emerged when the strength distribution of point obstacles representing precipitates was considered in the simulations. Conversely, simulations that assumed uniform strength of point obstacles led to an underestimation of the yield stress. This work proposes a framework that contemplates both spatial and strength distribution of point obstacles, offering an advance approach that outperforms previous yield strength models based on a linear superposition of strengthening mechanisms.

Active motion of tangentially driven polymers in periodic array of obstacles

One key question about transport of active polymers within crowded environments is how spatial order of obstacles influences their conformation and dynamics when compared to disordered media. To this end, we computationally investigate the active transport of tangentially driven polymers with varying degrees of flexibility and activity in two-dimensional square lattices of obstacles. Tight periodic confinement induces notable conformational changes and distinct modes of transport for flexible and stiff active filaments. It leads to caging of low activity flexible polymers inside the inter-obstacle pores while promoting more elongated conformations and enhanced diffusion for stiff polymers at low to moderate activity levels. The migration of flexible active polymers occurs via hopping events, where they unfold to move from one cage to another, similar to their transport in disordered media. However, in ordered media, polymers are more compact and their long-time dynamics is significantly slower. In contrast, stiff chains travel mainly in straight paths within periodic inter-obstacle channels while occasionally changing their direction of motion. This mode of transport is unique to periodic environment and leads to more extended conformation and substantially enhanced long-time dynamics of stiff filaments with low to moderate activity levels compared to disordered media. At high active forces, polymers overcome confinement effects and move through inter-obstacle pores just as swiftly as in open spaces, regardless of the spatial arrangement of obstacles. We explain the center of mass dynamics of semiflexible polymers in terms of active force and obstacle packing fraction by developing an approximate analytical theory.

Interplay of AI and IOT: Application and Challenges

This papеr undеrscorеs thе nеcеssity for collaborativе еfforts from acadеmia, industry, and policymakеrs to addrеss thеsе challеngеs and harnеss thе full potеntial of thе AI and IoT intеrplay. As thе tеchnology landscapе еvolvеs, it is impеrativе to strikе a balancе bеtwееn innovation and rеsponsibility, еnsuring that AI and IoT dеvеlopmеnts bring tangiblе bеnеfits whilе upholding privacy and sеcurity standards. In summary, thе intеrplay of AI and IoT prеsеnts a promising futurе of intеlligеnt, data-drivеn solutions, but it also dеmands carеful considеration of thе accompanying challеngеs to unlock its full potеntial.
 AI, given its capacity to process and comprehend extensive datasets, assumes a central role in amplifying the capabilities of IoT. This collaboration empowers IoT devices to gather, analyze, and act upon real-time data intelligently, fostering the development of more sophisticated and self-reliant systems. A wide array of applications arise from this synergy, spanning smart cities, healthcare, industrial automation, agriculture, and transportation.
 Nonetheless, the fusion of AI and IoT introduces a distinctive array of obstacles. These encompass apprehensions about safeguarding data privacy and security, the necessity for compatibility among diverse IoT devices and AI systems, ethical quandaries regarding AI-driven decision processes, and the imperative for robust infrastructure capable of accommodating the surging data volumes. Moreover, challenges pertaining to standardization and regulatory frameworks add further impediments to the seamless amalgamation of AI and IoT technologies.

Two-dimensional electron hydrodynamics in a random array of impenetrable obstacles: Magnetoresistivity, Hall viscosity, and the Landauer dipole

Two-dimensional electron hydrodynamics in a random array of impenetrable obstacles: Magnetoresistivity, Hall viscosity, and the Landauer dipole

Driven transport of active particles through arrays of symmetric obstacles.

We numerically examine the driven transport of an overdamped self-propelled particle through a two-dimensional array of circular obstacles. A detailed analysis of transport quantifiers (mobility and diffusivity) has been performed for two types of channels, channel I and channel II, that respectively correspond to the parallel and diagonal drives with respect to the array axis. Our simulation results show that the signatures of pinning actions and depinning processes in the array of obstacles are manifested through excess diffusion peaks or sudden drops in diffusivity, and abrupt jumps in mobility with varying amplitude of the drive. The underlying depinning mechanisms and the associated threshold driving strength largely depend on the persistent length of self-propulsion. For low driving strength, both diffusivity and mobility are noticeably suppressed by the array of obstacles, irrespective of the self-propulsion parameters and direction of the drive. When self-propulsion length is larger than a channel compartment size, transport quantifiers are insensitive to the rotational relaxation time. Transport with diagonal drives features self-propulsion-dependent negative differential mobility. The amplitude of the negative differential mobility of an active particle is much larger than that of a passive one. The present analysis aims at understanding the driven transport of active species like, bacteria, virus, Janus particle etc. in porous medium.