Local Forces Research Articles

Surviving the educational landscape: a case study of leadership, policy tensions and marketisation

Within a neoliberal educational policy context, we are increasingly witness to educational leaders compelled to become strategic operators to ensure the survival of their schools. Drawing on the tenets of institutional ethnography (IE), this article traces the everyday work and experience of a school leader in one Australian private school site that was in ‘survival mode’ after experiencing an unprecedented decline in enrolment numbers. By tracing the power of global and local market forces informing the work of one educational leader, our intention is to capture how a school leader’s subjectivity was influenced by market demands and how he invested his time in strategizing to ensure his school would survive. The article makes two main contributions; first, the case study complements research exploring the impact of neoliberal reform on schooling and, second, we highlight the role of IE in furthering our understanding of the pressures schools face and the lived experience of school leaders.

Indonesian Islamic Tradition is a Wisdom that Liberates Society from the Shackles of Globalization

This study aims to describe Islamic traditions in Indonesia as a source of law to free society from the shackles of globalization. This research is qualitative with a literature model. Research data in the form of Islamic traditional activities in the community. Data sources were obtained from several recent studies. Data collection was done using documentation technique. Meanwhile, data analysis was done using content analysis. The research findings show that Indonesian Islamic traditions have inherent values and teachings that can help communities strengthen their local strength and resist the negative influences of consumer culture and global hedonism. By integrating Islamic values with the local context, critical education can serve as a powerful tool to empower individuals and communities to resist the damaging effects of globalization. In conclusion, the Indonesian Islamic tradition holds valuable wisdom that can guide us in navigating the complexities of the modern world. By harnessing this wisdom and integrating it with critical education, we can strengthen local forces and resist external pressures, thus freeing ourselves from the shackles of globalization.
 Keywords: globalization, Indonesian Islamic tradition, neoliberalism

Utilizing augmented reality for the assembly and disassembly of panelized construction

Prefabricated construction allows for efficient resource usage while creating higher-quality products that can be assembled on-site within a short time. While this translates to significant benefits for the overall construction, challenges arise from an increased demand for trained prefabrication assembly workers. As prefabrication calls for skills differing from traditional construction, the local labor force can be negatively affected to impede the successful uptake of prefabricated construction. Upskilling the local workforce to take on prefabrication assembly and potential disassembly can solve this problem. This is more relevant to remote construction projects as they stand to gain more from prefabricated construction. This study presents two workflows for creating Augmented Reality (AR) solutions. The AR solutions are aimed to help workers transition between traditional and prefabrication assembly in a panelized construction project. They are: (1) using QR codes to identify a panel’s intended location and construction sequence and (2) using predefined markers to show required equipment and on-site assembly procedures. The solutions are delivered through smartphones, which are readily available and provide a cost-effective medium. Furthermore, developed workflows present an opportunity to implement Design for Disassembly (DfD) concepts in a project. The proposed workflows show the potential to substantially help communicate to the workers the instructions on both the panel assembly and disassembly activities and upskill the local workforce to support the transition to prefabrication assembly in construction projects.

КРУЧЕНИЕ НИЖНЕГО ПОЯСА ПОДКРАНОВО-ПОДСТРОПИЛЬНОЙ ФЕРМЫ

The lower belt of the crane secondary truss, along which the crane moves, is made of a thin-walled box profile. The largest local concentrated crane forces applied with eccentricity to the lower belt of truss made of thin-walled welded box cause its restrained torsion. The calculation method of the crane secondary truss does not consider the inclusion in the work of the lower belt for torsion and horizontal bending of the webs. A beam with a span equal to the span of the crane secondary truss is taken as the design scheme of the lower belt along which the crane moves. In fact, the work of the belt during torsion is different from the work of the beam.
 The objectives of the work are to assess the impact on the operation of the lower belt during torsion of the webs and the upper belt and to clarify the methodology for calculating the lower belt. The study of the influence of webs on the angular malleability and torque of the lower belt has been carried out. Various ratios of the stiffness of the belt and the entire crane secondary truss are considered. The design scheme of the belt for the calculation of torsion is proposed – a beam angular elastic supports at the points of junction of the webs. The formula for determining the stiffness of elastic supports has been adopted. The error in determining the bending moments in the lower belt according to the proposed method relative to the results of numerical calculation of the rod design scheme of the entire crane secondary truss does not exceed 2%. The stresses in the lower belt, considering the torsion component, are analytically determined. The results were verified numerically using shell finite elements and a full-scale examination.

Lattice modelling of early-age creep of 3D printed segments with the consideration of stress history

We propose a new numerical method to analyze the early-age creep of 3D printed segments with the consideration of stress history. The integral creep strain evaluation formula is first expressed in a summation form using superposition principle. The experimentally derived creep compliance surface is then employed to calculate the creep strain in the lattice model with a combination of stored stress history. These strains are then converted into element forces and applied to the analyzed object. The entire numerical analysis consists of a sequence of linear analyses, and the viscosity is modelled using imposed local forces. The model is based on the incremental algorithm and one of the main advantages is the straightforward implementation of stress history consideration. The creep test with incremental compressive loading is utilized to validate this model. The modelling results are in good agreement with experimental data, demonstrating the feasibility of the lattice model in early-age creep analysis under incremental compressive loading. To understand the impact of early-age creep on structural viscoelastic deformation during the printing process, additional analyses of a printed segment are carried out. These simulation results highlight the need to consider creep for accurate prediction of viscoelastic deformation during the printing process.

Einstein Model of a Graph to Characterize Protein Folded/Unfolded States.

The folded structures of proteins can be accurately predicted by deep learning algorithms from their amino-acid sequences. By contrast, in spite of decades of research studies, the prediction of folding pathways and the unfolded and misfolded states of proteins, which are intimately related to diseases, remains challenging. A two-state (folded/unfolded) description of protein folding dynamics hides the complexity of the unfolded and misfolded microstates. Here, we focus on the development of simplified order parameters to decipher the complexity of disordered protein structures. First, we show that any connected, undirected, and simple graph can be associated with a linear chain of atoms in thermal equilibrium. This analogy provides an interpretation of the usual topological descriptors of a graph, namely the Kirchhoff index and Randić resistance, in terms of effective force constants of a linear chain. We derive an exact relation between the Kirchhoff index and the average shortest path length for a linear graph and define the free energies of a graph using an Einstein model. Second, we represent the three-dimensional protein structures by connected, undirected, and simple graphs. As a proof of concept, we compute the topological descriptors and the graph free energies for an all-atom molecular dynamics trajectory of folding/unfolding events of the proteins Trp-cage and HP-36 and for the ensemble of experimental NMR models of Trp-cage. The present work shows that the local, nonlocal, and global force constants and free energies of a graph are promising tools to quantify unfolded/disordered protein states and folding/unfolding dynamics. In particular, they allow the detection of transient misfolded rigid states.

Physical and mechanical properties of vulcanized and filled rubber at high strain rate

The purpose of this study is to investigate -at nanoscale- cis-Polyisoprene(cis-PI), the main component of natural rubber. This system is vulcanized by adding elemental sulfur to cis-PI and vulcanizing at high temperature to obtain vulcanized rubber. The study is extended to cis-PI including different amounts of fullerenes to the vulcanized rubber at high temperature in order to obtain carbon black filled vulcanized rubber. The physical and thermodynamic properties of vulcanized rubber as well as carbon black-filled vulcanized rubber were studied to shed light on the effects of vulcanization and nanofiller on natural rubber. The interaction between fullerenes and cis-PI atoms and the aggregation configuration of cis-PI atoms around fullerenes were analyzed in details by introducing local number density and potential mean force (PMF) through radial distribution function (RDF). Besides, various mechanical quantities were obtained at different temperatures with and without nanofiller.

Study of interwall interaction during the pull separation of ultra-long double-walled carbon nanotubes under lateral loading

The successful fabrication of ultra-long carbon nanotubes (CNTs) makes CNTs ideal candidates for bearing systems due to the long sliding distance with low interwall interaction. However, it is difficult to measure the pull-out forces of ultra-long CNTs along their axes in real-time because of the difficulty of performing long-distance pull-out experiments. In this study, we proposed a lateral loading method to measure the interwall interaction force of ultra-long CNTs. By using a theoretical model and multi-scale finite element simulations, we could predict the interwall interaction force from the pull-out force in lateral loading. This pull-out force depends on the length of CNTs, and a critical length divides the pull-out force into two categories: maximum pull-out force due to local buckling and steady pull-out force due to sliding. In order to correctly measure the interwall interaction force by lateral loading, for the DWCNTs with the outer tube diameter of 0.955 nm, we have to make sure the lengths are greater than this critical value (54.2 nm) as experimental subjects.

Police as first reponders improve out-of-hospital cardiac arrest survival

BackgroundPolice forces are abundant circulating and might arrive before the emergency services to Out-of-Hospital-Cardiac-Arrest victims. If properly trained, they can provide basic life support and early defibrillation within minutes, probably increasing the survival of the victims. We evaluated the impact of local police as first responders on the survival rates of out-of-hospital cardiac arrest victims in Navarra, Spain, over 7 years.MethodsA retrospective analysis of an ongoing Out-of-Hospital Cardiac registry to compare the characteristics and survival of Out-of-Hospital-Cardiac-Arrest victims attended to in first place by local police, other first responders, and emergency ambulance services between 2014 and 2020.ResultsOf 628 cases, 73.7% were men (aged 68.9 ± 15.8), and 26.3% were women (aged 65,0 ± 14,7 years, p < 0.01). Overall survival of patients attended to by police in the first place was 17.8%, other first responders 17.4% and emergency services 13.5% with no significant differences (p > 0.1). Time to initiating cardiopulmonary resuscitation is significant for survival. When police arrived first and started CPR before the emergency services, they arrived at a mean of 5.4 ± 3 min earlier (SD = 3.10). This early police intervention showed an increase in the probability of survival by 10.1%.ConclusionsThe privileged location and the sole amount of personnel of local police forces trained in life support and their fast delivery of defibrillators as first responders can improve the survival of out-of-hospital cardiac arrest victims.

Pelaksanaan Pembelajaran Tatap Muka Di SMK Kristen 1 Surakarta Pada Era New Normal

The aims of this study were to: (1) Find out how the implementation of face-to-face learning at SMK Kristen 1 Surakarta in the new normal era. (2) Knowing the obstacles faced in the implementation of face-to-face learning at SMK Kristen 1 in the new normal era. (3) Knowing the solution to overcome the obstacles in the implementation of face-to-face learning at Christian Vocational High School 1 in the new normal era. This research is a qualitative descriptive study. Sources of data used in this research are informants, places and events, and documentation. The sampling technique used is purposive and snowball sampling. Data collection techniques used are interviews, observation and documentation. The validity of the data used is source triangulation and method triangulation. While the data analysis used is an interactive analysis model.The results of the study: (1) The implementation of face-to-face learning at SMK Kristen 1 Surakarta has been well organized and guided by government regulations, for initial preparations to form an internal Covid-19 task force team, licensing the local education office, notification to parents containing SOPs as technical face-to-face learning and held a limited face-to-face learning simulation which was attended by several students who had been vaccinated together with BK teachers and the local covid-19 task force. For its implementation, the curriculum used is a simplified curriculum by shortening the duration of learning. Procurement of facilities according to health protocols as another mandatory preparation. Meanwhile, for evaluation during PTM there is a reduction in the duration of learning and the advantages of PTM, students absorb more material during face-to-face learning. (2) The obstacle felt by SMK Kristen 1 Surakarta is the difficulty in inculcating the habit of wearing masks correctly while at school. (3) Coordinate with parents, the Covid task force team and also teachers to remind each other and provide direction for students who violate.

The Role of Shear Stress in Coronary Artery Disease.

Coronary artery disease is the leading cause of morbidity and mortality worldwide, especially in developed countries, with an increasing incidence in developing countries. Despite the advances in cardiology, there are yet many unanswered questions about the natural history of coronary atherosclerosis. However, it has not been fully explained why some coronary artery plaques remain quiescent over time, whereas others evolve to a high-risk, "vulnerable" plaque with a predisposition to destabilize and induce a cardiac event. Furthermore, approximately half of the patients with acute coronary syndromes demonstrate no prior symptoms of ischemia or angiographically evident disease. Recent findings have indicated that apart from cardiovascular risk factors, genetics, and other unknown factors, local hemodynamic forces, such as endothelial shear stress, blood flow patterns, and endothelial dysfunction of the epicardial and microvascular coronary arteries, are associated with the progression of coronary plaque and the development of cardiovascular complications with complex interactions. In this review article, we summarize the mechanisms that affect coronary artery plaque progression, indicating the importance of endothelial shear stress, endothelial dysfunction of epicardial and microvascular vessels, inflammation, and their complex associations, underlying in parallel the clinical perspectives of these findings.

Blockchain-Powered Tensor Meta-Learning-Driven Intelligent Healthcare System With IoT Assistance

The rapid development and gradual integration of artificial intelligence and the Internet of Things have brought unprecedented opportunities for radically changing healthcare and treatments. However, the burgeoning in intelligent healthcare systems is severely bounded by data privacy and the security of AI models. Meanwhile, the limited local data forces conventional AI models to face the predicament in achieving personalized healthcare. Hence, we propose a blockchain-powered tensor meta-learning-driven intelligent healthcare system with IoT assistance. IoT devices as light nodes upload the local shareable data to the edge server(full node) for model training and perform the local private data by non-tampered model downloaded via smart contract. The system can not only use blockchain technology to ensure the strong consistency of the healthcare model but also protect private data from being leaked. Especially, we develop a tensor meta-learning model named tensor-prototype graph network to achieve efficient modeling of heterogeneous healthcare data. Building on the tensors and graph network, the model is conducive to capturing the data distribution when there are few labeled data. To evaluate our proposed approach, we have conducted experiments on three classic databases. The results demonstrate that our approach is capable of effectively promoting the performance of intelligent healthcare.

НАГРУЖЕНИЕ ТЕЛЕСКОПИЧЕСКОЙ СТРЕЛЫ ОТ МЕСТНЫХ НАГРУЗОК В ПРОЦЕССЕ ТЕЛЕСКОПИРОВАНИЯ

One of the main factors affecting the performance of telescopic booms is the loss of local stability of the shelves and section walls. The loss of local stability of the sections occurs due to the development of plastic deformations in some of the most loaded sections of the telescopic booms or as a result of the loss of stable equilibrium of the sections even at the stage of elastic deformation. In this case, the maximum stresses of the telescopic boom are formed in the sections of the location of the supporting elements, where the summation of deformations from external loads and forces acting from the side of the supporting elements (local loads) occurs. The aim of the work is to study the loading of telescopic boom from the action of local forces in the process of telescoping. Analysis of the loading of telescopic boom in the process of extending (retracting) the sections is carried out using the example of the boom equipment of a railway crane Sokol 80.01M. Numerical modeling is used to study the local loading of telescopic boom of a crane during telescoping. Three telescoping modes are selected: consecutive extension (retraction) of sections without load; synchronous extension (retraction) of sections without load; consecutive extension (retraction) of sections with a load. The results of the virtual experiment for each mode are the time dependences of the local forces generated at the locations of the sliding bearings, and the time dependences of the vertical loads on the pins of the telescoping hydraulic cylinders. A comparison was made of the greatest loadings of the boom and telescoping hydraulic cylinders formed with three options for extending (retracting) sections. Based on the obtained dependencies of local loads, the maximum stresses of the telescopic boom were calculated during each telescoping mode.

고려 후기 忠州城의 신지견

This article examines the consistency of the location of Chungjuseong [meaning Chungju Fortress and in other words, Chungju Sanseong meaning Chungju Mountain Fortress], the site of one of the most dramatic battles of the Goryeo-Mongol War(1231-1273), through the perspective of a new discovery. Various hypotheses related to Chungjuseong Fortress have emerged so far, such as Nam Sanseong, Daerim Sanseong, Chungju Eupseong, Deokju Sanseong, etc. Among them, Chungju Eupseong as the fortress of the province and Daerim Sanseong as the mountain fortress have been regarded as persuasive. However, serving as a mountain fortress for defense and protection was done at high and rugged mountain fortresses such as Yang sanseong, Yanggeunseong, Cheonryong Sanseong, and Ibam Sanseong, which are recorded in the literature. In line with this, the fortress site of Gyejoksan Mountain in Chungju proved to have conformity with Chungju Fortress [Chungju Sanseong]. Until now, the fortress site of Gyeyoksan Mountain has been recognized as an extension of the territorial range of Simhanghyeon in the Joseon Dynasty. Thus, the walls were thought to be not related to Chungju Sanseong during the Goryeo-Mongol War. However, Mt. Gyejoksan (now Mt. Gyemyungsan) is the main mountain of Chungju and shows a rugged mountainous position for a fortress site. In addition, based on the main defense direction toward Chungju Town, construction technique of the Goryeo Dynasty, and excavated artifacts, the site was judged to be highly likely to be related to Geum Yun-hu, who was a defense official of Chungju Sanseong. In other words, it was the site of battles such as the 1st(1231),5th(1253), and6th (1256) Mongol invasions. In between, the battles of Geumdanggyeop (1253), Daincheolso (1254), Daewonryeong (1255), and Parkdalhyeon (1258) are also believed to have occurred around this place. The Mongolian method of warfare in the Goryeo-Mongol War was to use local forces that had surrendered to the Mongols. This has the vulnerability of exposing internal information in the battles to defense the capital. In other words, a Goryeo army had to fight against another Goryeo people combined with Mongolian army. The Battle of Chungju Sanseong (1253) had significance in that it provided the opportunity to overcome and recover the asymmetry of this strategy through tripod-shaped terrain site, the high and rugged location, and the guerrilla warfare. This is the first time the outline of the fortress site of Gyejoksan Mountain has been identified. We hope that it will shed new light on the location of Chungjuseong [Chungju Sanseong] in the late Goryeo Dynasty and its historical development. It is also hoped that academic research on the Gyeyoksan fortress site will be conducted in a systematic manner so that the overall status, structure, and consecration techniques of the fortress can be clarified.

Targeted mechanical stimulation via magnetic nanoparticles guides in vitro tissue development

Tissues take shape through a series of morphogenetic movements guided by local cell-scale mechanical forces. Current in vitro approaches to recapitulate tissue mechanics rely on uncontrolled self-organization or on the imposition of extrinsic and homogenous forces using matrix or instrument-driven stimulation, thereby failing to recapitulate highly localized and spatially varying forces. Here we develop a method for targeted mechanical stimulation of organoids using embedded magnetic nanoparticles. We show that magnetic clusters within organoids can be produced by sequential aggregation of magnetically labeled and non-labeled human pluripotent stem cells. These clusters impose local mechanical forces on the surrounding cells in response to applied magnetic fields. We show that precise, spatially defined actuation provides short-term mechanical tissue perturbations as well as long-term cytoskeleton remodeling in these organoids, which we term “magnetoids”. We demonstrate that targeted magnetic nanoparticle-driven actuation guides asymmetric tissue growth and proliferation, leading to enhanced patterning in human neural magnetoids. This approach, enabled by nanoparticle technology, allows for precise and locally controllable mechanical actuation in human neural tube organoids, and could be widely applicable to interrogate the role of local mechanotransduction in developmental and disease model systems.

Multi-year variability of summer phytoplankton biomass and size structure in the northern Chukchi and East Siberian Seas, Arctic Ocean: role of light and nutrient availability

In the Arctic Ocean, the northern Chukchi and East Siberian Seas (NCESS) are vulnerable to climate change due to warming, sea ice melting, and surface freshening. To investigate how local physical forcing affects phytoplankton biomass and communities in this area, the multi-year (2015-2020) distributions of summer (August) chlorophyll-a concentrations and size structures using data collected by the Korea-Arctic Ocean Observing System (K-AOOS) program were investigated. The environmental characteristics and phytoplankton communities in the study area showed east-west regional differences. It is characterized by warm fresh waters and strong stratification to the east and cold saline waters and relatively high nutrient and sea ice concentrations to the west. Despite the differences between the east and west regions, patterns of the inter-annual variation in phytoplankton biomass and communities were similar across the entire study area, implying environmental controllers regulating phytoplankton in the NCESS. Inter-annually, higher sea surface salinity and weaker water column stratification were observed in 2017-2019 than in 2015 and 2020, implying the possibility of a potential modulation by the Arctic Oscillation. The shallower nitracline depth and higher surface nutrient concentrations since 2017 compared to the period from 2015-2016, indicate improved nutrient availability due to Atlantic water intrusion. However, average insolation has been relatively low since 2017, with the exception of August 2018. August mean phytoplankton biomass was highest in 2018 in the study area (average 83.7 mgm-2) and was dominated by large-sized phytoplankton. The low phytoplankton biomass in 2017 (23.9 mgm-2) and 2019 (62.4 mgm-2), despite similar characteristics of nutrient concentration to 2018, is likely due to lower average daily insolation in both years (206 μEm-2d-1 and 184 μEm-2d-1 in 2017 and 2019, respectively) compared to the 2018 average (271 μEm-2d-1). These results suggest that increased intrusion through upwelling of Atlantic water, along with nutrient loading, could be a pivotal driving factor contributing to this enhanced production in the NCESS, particularly under conditions where light levels are sufficient for phytoplankton growth and bloom development.

Thunderstorm detection from GPM IMERG rainfall: Climatology of dynamical and thermodynamical processes over India

AbstractThis study aims to (i) prepare a premonsoon thunderstorms database, (ii) understand the thunderstorm frequency, duration and intensity and (iii) composite analysis of dynamic and thermodynamic processes related to thunderstorms over India. The thunderstorm associated rainfall varies across India. Hence, a percentile‐based approach is implemented with the integrated multi‐satellite retrievals for global precipitation measurement (IMERG) dataset at 0.1° resolution to identify thunderstorms for 2001–2021. The 93rd percentile appears to be better for thunderstorm detection, with a success ratio of 82% (642 events are confirmed out of 786 detected) in eastern India. Further analysis indicated that 84% of the detected thunderstorms in eastern and northeastern India are associated with lightning activity. Based on this long‐term (2001–2021) thunderstorm data, the highest frequency of thunderstorms (40–45 events·year−1) is observed over the western foothills of the Himalayas, the northeast region, and the west coast of Kerala. The thunderstorm duration in the eastern and northeastern regions and the southwest coast of India is mostly 0.5–2.5 h, producing heavy rainfall (&gt;7 mm·h−1) due to more moisture content and stronger updrafts. The composite structure of thermodynamic indices exhibits significant spatial variations over India and can be used to differentiate the regions of high thunderstorm activity. The minimum (maximum) convective available potential energy (convective inhibition) value required for thunderstorm development is not uniform throughout the country. However, the composites of K index and total totals index during thunderstorms are mostly uniform. This study highlights the benefits of IMERG rainfall in thunderstorm detection over India and helps to understand the local forcings and the effect of thunderstorm activity on different sectors like aviation, agriculture and so forth.

Machine learning assisted resistive force theory for helical structures at low Reynolds number

The hydrodynamic forces on a slender rod in a fluid medium at low Reynolds number can be modeled using resistive force theories (RFTs) or slender body theories (SBTs). The former represent the forces by local drag coefficients and are computationally cheap; however, they are physically inaccurate when long-range hydrodynamic interaction is involved. The later are physically accurate but require solving integral equations and, therefore, are computationally expensive. This paper investigates RFTs in comparison with state-of-the art SBT methods. During the process, a neural network-based hydrodynamic model that – similar to RFTs – relies on local drag coefficients for computational efficiency was developed. However, the network is trained using data from an SBT (regularized stokeslet segments method). The R2 value of the trained coefficients were ∼0.99 with mean absolute error of 1.6×10−2. The machine learning resistive force theory (MLRFT) accounts for local hydrodynamic forces distribution, the dependence on rotational and translational speeds and directions, and geometric parameters of the slender object. We show that, when classical RFT fails to accurately predict the forces, torques, and drags on slender rods under low Reynolds number flows, MLRFT exhibits good agreement with physically accurate SBT simulations. In terms of computational speed, MLRFT forgoes the need of solving an inverse problem and, therefore, requires negligible computation time in comparison with SBT. MLRFT presents a computationally inexpensive hydrodynamic model for flagellar propulsion can be used in the design and optimization of biomimetic flagellated robots and analysis of bacterial locomotion.

(Invited) Investigation on Dynamics of Expansion Forces and Dimensions Changes of the Pilot Scale Electrodialysis Stack

Electrodialysis (ED) represents a matured and well-established desalination and electromembrane separation technology with typical plate-and-frame configuration. In order to satisfy application demands, there is a trend for an increasing dimension and operating temperature of the industrial ED capable of high performance and efficiency in view of process time and system volume. These activities are motivated mainly by process cost reduction and exploiting new application fields benefiting from higher operating temperature and higher performance-to-volume ratio. This is also the case of reverse electrodialysis, currently meeting a growing popularity as a promising green energy source. However, experiences in a development of larger scale electromembrane devices show that scale-up from laboratory or pilot system to industrial ones is not straightforward. The scale-up simply based on increasing membrane active area or number of membranes, without appropriate modifications of entire unit design, often lead to accentuation of negative effects that are normally negligible on a small scale.One of the critical issues in larger scale represents dimensional changes of the ED stack, mainly due to membranes swelling and changes of mechanical properties of the stack materials as a respond to variation of operating conditions (temperature, electric current, salt concentration). When a robust rigid frame is used for stack assembly, such stack expansion may lead to an increase of the internal expansion forces causing irreversible mechanical damage of the materials used (membranes, spacers). On the contrary, the stack shrinking (e.g. due to membrane drying and deswelling) negatively affects the tightness. Consequently, the performance, reliability and lifetime of the apparatuses can be significantly exacerbated. Therefore, an autonomous (passive or active) system of compression force control has to be employed, which at each moment spontaneously adapts to stack dimensions keeping compression/expansion force at an optimal value. However, prior to a development of such system a deeper fundamental understanding of the stack behaviour is required. We are mainly interested at a) a qualitative and quantitative respond of the stack internal forces upon variation of different operating parameters, b) uniformity of distribution of internal expansion forces, c) dynamics (characteristic times) and reversibility of the stack dimensional changes, d) effect of different compression forces and stack compression-expansion cycles to longer-term operation of the stack and also e) stack tightness.In the first part of presented contribution the basic principle of electrodialysis process, system design and critical aspects of the ED process operation in industrial practice will be discussed. Next, the results of the research aimed at investigation of the dimensional and expansion forces changes in the pilot electrodialysis stack will be presented. The pilot-scale ED unit consists of 100 membrane pairs equipped by heterogeneous anion- and cation-selective membranes. Working area is of 0.4 × 0.1 m2. The stack is orientated horizontally assembled into the robust frame made of aluminum Item® profiles. A rigid endplate is attached to one side of the stack, whereas the opposite end-plate is segmented and equipped by 6 tensiometers measuring local stack expansion force. This compression force is applied to the stack by six pneumatic cylinders with equal pressure pressurized by a one standard compressor. The aspects of the stack behavior mentioned above are investigated as a dynamic respond of the stack to sudden changes in operating temperature (20 – 65 °C), electric current, salt concentration (0 – 160 g/dm3) and compression force (up to 45 kN). Different regimes are investigated: a) a regime with constant compression force in the pneumatic cylinders, or b) constant stack dimension (rigid compression frame) during the entire experiment. It was found that the effect of temperature was significantly more pronounced than the effect of salt concentration and electrical current. Moreover, up to 3 different characteristic times in the stack dynamic respond to temperature change were found.The financial support from grant agency of Ministry of Trade and Industry of the Czech Republic within program TRIO (project TOM2022 no. FV40053) is gratefully acknowledged.

Localized magnetic fields and their effects on heat transfer enhancement and vortices generation in tri-hybrid nanofluids: A novel investigation

A localized magnetic field is a vector field that alters in space because of magnetic materials or electric currents. Some examples of localized magnetic fields are indoor localization, magnetic anomaly detection, magnetoencephalography, and quantum physics. Magnetic fields can be used to estimate the orientation and position of a device inside a building by measuring the changes in the magnetic field caused by ferromagnetic substances. On the other hand, a Tri-hybrid nanofluid can transfer heat better than a normal hybrid nanofluid by mixing three different nanoparticles with synergistic effects. It can have more varied physical and thermal properties by choosing different combinations of nanoparticles. That's why it has more possible uses in various fields such as solar thermal, biomedical, and industrial processes. Therefore, the goal of this research is to explore the complex dynamics of the localized magnetized force that affects the rotation of nanostructures and the vortex formation in the tri-hybrid nanofluid flow regime using the single-phase model, while the governing partial differential equations are discretized numerically. With the help of our self-developed computer codes in MATLAB language, we intend to understand the way these parameters affect the flow and thermal properties of the nanofluids. Additionally, the current work provides a novel analysis that makes it possible to investigate the flow lines and isotherms associated with the magnetic strips inside a flow field. It is discovered that the spinning of tri-hybrid nano-particles, which creates the intricate structure of vortices inside the flow regime, results from the magnetized field. Further, the investigations reveal that both the local skin friction (CfRe) and the Nusselt number (Nu) increased by up to 46% and 99% when the magnetic field is strengthened. Finally, adding more nanosized particles in the flow field result in increased both Nu and CfRe, but differently for different nanoparticles. Silver (Ag) had the highest increase in both Nu (55%) and CfRe (110%), showing strong thermal-fluid coupling. Alumina Al2O3 and Titanium Dioxide (TiO2) had lower increases in both Nu (33% and 25%) and CfRe (13% and 9%), showing weaker coupling in the flow regime.