Flexible Construction Research Articles

Optimization of Power Supply Structure Considering Carbon Emissions and Flexibility

Against the backdrop of China’s promotion of green and low-carbon energy transformation, the large-scale and high-proportion development of new energy has made flexible regulation of power supply planning a key link in the flexible construction of the power system. Considering the balance of flexible supply and demand and minimizing carbon emissions, a mid to long-term collaborative planning model for electricity and flexibility is proposed. According to the planning principles of economic efficiency, clean environmental protection, and safety and reliability, a dynamic planning model was constructed to minimize the total cost of electricity production and carbon emissions in the entire society. Taking into account constraints such as carbon peaking goals and electricity balance, taking a certain region in China as an example, a flexible power supply structure optimization planning is carried out to solve carbon emission levels and system costs, output carbon peaking time, and optimal path plan.

Application of Microtremor Survey Technology in a Coal Mine Goaf

Goafs are one of the main factors that endanger the safety of mining areas, leading to roadway collapse, land subsidence and other problems. Determining how to detect goafs accurately and efficiently is an important issue faced in engineering geophysical exploration research. Microtremor survey technology, used in geophysical exploration, has been developed in recent years. It has the advantages of low cost, flexible construction, low topographic impact and high efficiency. In this paper, microtremor survey technology was applied to the detection of a coal mine goaf. In the known goaf area of the Taiyuan Nanling Coal Mine, a linear observation array was arranged to conduct rolling acquisition, observe the microtremor signal records of the natural field and use the extended spatial autocorrelation method to extract the dispersion curve. Through the inversion of the extracted dispersion curve, the apparent shear wave velocity profile of the underground medium clearly showed the location of the goaf. It was roughly consistent with the goaf data obtained from the mine. The detection results reflect the advantages of micromotion exploration. The goaf of Coal Seam #2 and its affected area appear to be due to an obvious low-speed phenomenon. The boundary of the apparent shear wave velocity profile of micromotion detection was basically consistent with the boundary of the goaf, indicating that micromotion exploration technology has good technical advantages and application prospects in the detection of coal mine goafs. The rolling acquisition method of linear arrays can be used to ensure accurate detection, improve exploration efficiency and save on exploration costs.

Flexible Organic Light-Emitting Diodes: Structure and Fabrication

Flexible organic light-emitting diodes (OLED) technology with thin, light in weight, and free in design have been developed and perfected rapidly. The versatility of flexible OLED technology has been effectively proved in the sectors of displays, lighting, and medicine. In this article, the structure and fabrication of flexible OLED were introduced. Normal flexible OLED device construction includes flexible OLED substrate, barrier layers, electrode and organic layer. The flexible OLED is made on the substrate. The barrier layer is used to shield the OLED material from airborne oxygen and humidity. The electrodes are used for electricity, and the organic layer is used for light. The production processes of flexible OLED include coat-debond with advantages such as good stability and thermal conductivity, bond-debond with the advantage of simple and convenient and roll-to-roll [R2R] method with advantages of low cost, and mass production. Additionally, the application fields of these methods have been highlighted.

Flexibility in primary medical programs: A scoping review

Introduction: Students and universities increasingly seek flexibility in learning options, however terms such as flexible are not consistently defined in the medical education literature. This review aimed to 1) propose a definition for flexibility in medical education and 2) create a typology of contemporary examples of how flexibility has been operationalised in medical education. Method: A systematic scoping review of papers published in English since 2009 was undertaken. The focus was on papers reporting initiatives to create flexibility in primary medical programs. Results: Based on review of 1,641 search returns and 140 full-text articles, two interconnected concepts were identified: flexibility and individualisation. Flexibility describes mechanisms that allow students choice in how they allocate time and resources to meet the requirements of their course, including time-variable progression, acceleration, deceleration, articulated degree entry and exit options, and pedagogical approaches that reduce time required in classrooms. Individualisation describes options that enable student-driven direction, extension or expansion of medical education into special interest areas, including dual degrees, breadth subjects, curriculum tracks, elective service-learning pathways, electives and selectives. Conclusions: Though not always clearly defined as such, international medical education literature describes a rich variety of flexibility and individualisation initiatives. While the constructs of flexibility and individualisation are interconnected, they can assist curriculum designers to differentiate between the mechanisms that enable flexibility in how students meet course requirements and the mechanisms that enable individual choice in what students study. Flexibility and individualisation initiatives target different needs, including both students’ needs and medical workforce needs; they also suggest different institutional and financial implications. Consensus on and consistent use of common terminology about flexibility and individualisation initiatives will improve the “searchability” and synthesis of research on such initiatives and their impacts and enablers, as well as encourage further research, publication and synthesis of outcomes of such initiatives.

ANALYSIS OF THE INFLUENCE OF AIR TEMPERATURE ON THE COMPACTION OF ASPHALT DURING INSTALLATION

In this paper, the influence of air temperature on asphalt compaction during installation was investigated. The reason for this research is that during the construction of roads or the reconstruction of existing ones, the need to completely or partially replace the asphalt layers of the flexible pavement structure most often arises. The lifespan of a flexible pavement construction, i.e. road, always depends on the quality of the subgrade, but also on the quality of the final asphalt works. In order to arrive at the best possible procedure for installing the asphalt mixture, research was carried out on several concrete examples, observing the air temperature through the compaction feature of the installed asphalt, that is, through the required number of roller passes during the installation of the asphalt mixture. During the research, numerous other data that are important for the research were measured, such as the weight of the rollers, the temperature of the asphalt at the construction site, etc. On the basis of the obtained results, sorting and analysis of the same was carried out. Based on the analysis of the obtained results, conclusions were reached. Keywords: air temperature during asphalt installation, asphalt mixture temperature, asphalt compaction

Asphalt Mixtures and Flexible Pavement Construction Degradation Considering Different Environmental Factors

Water, frost, and road salt are counted as environmental factors. They affect the pavement structure, particularly during the winter or in regions located above sea level. In the article, a literature review related to water, frost, and road salt impacts was performed. The main problem of evaluating asphalt mixture degradation and its influence on pavement fatigue life via environmental factors was stated. Four types of asphalt concrete (AC22) road mixes were prepared for laboratory tests. They differed in production technology and the type of binder applied. One binder content level was tested. To investigate the impact of water, frost, and road salt on mineral-asphalt mixtures utilized in flexible constructions, two proprietary experimental methods were applied. Methods allowed for determining the mixtures’ degradation level using the measured stiffness modulus in the 4-PB-PR test. Based on the obtained results, it was found that both interactions cause a significant decrease in the value of the stiffness modulus. In the article, a degradation ratio was proposed. The ratio expressed the impact of water, frost, and road salt on the stiffness mix variability. Its value was considered for pavement fatigue life based on the AASHTO 2004 fatigue criterion. The article demonstrates that the type of binder used influences the mix’s resistance to water, frost, or road salt impact. The highest resistance was reached by a mixture with highly modified asphalt (hot technology), and the worst was with asphalt WMA (warm technology). It has also been proven that the impact of water, frost, or road salt on pavement fatigue life is significant. The drop was significant, amounting to a few dozen percent. It was stated that environmental impacts (such as water, frost, or road salt) should be considered in asphalt mixture and pavement construction design.

An integrated framework for improving the efficiency and safety of hydraulic tunnel construction

Drilling and blasting is the most flexible tunnel construction method considering the excavation of tunnel size and shape. Schedule and safety are two critical issues for project stakeholders during construction. To evaluate construction quality, various tools such as Building Information Modelling (BIM), schedule simulation, and numerical analysis are commonly employed. However, in current practices, these processes are often independent of each other, requiring data conversion and operation between multiple platforms. In this paper, we present a novel integrated framework for improving the safety and efficiency of hydraulic tunnel construction. To this end, a geometric tunnel model with time attribute is created, which connects the schedule information obtained by construction simulation via secondary development. Then a numerical simulation method coupled with construction schedule is introduced to the integrated framework, which can automatically process the numerical model and perform analysis and calculation combined with the schedule information. In addition, this paper proposes a parameterization method of the rock bolt numerical model to realize the evaluation of different support schemes. The proposed method can avoid tedious manual operations to reduce possible errors. Finally, we propose a multistep prediction model of surrounding rock deformation based on Long Short-Term Memory (LSTM). The framework integrates the above functions via secondary development, scripting, and other technologies, and demonstrates the reliability of the framework with a tunnel project. The proposed integrated framework provides an intuitive and efficient tunnel construction management method hence promoting the information flow of multiple participants and multiple professionals in tunnel construction and providing decision support.

High efficiency and flexible construction of hydrophilic polymer brushes on polyether ether ketone hollow-fiber membrane surface for improving permeability separation, and anti-fouling performances

Polyether ether ketone (PEEK) is a high-performance thermoplastic used as a separation membrane for wastewater treatment, purification, and recycling, especially in harsh environments. However, the applications of PEEK membranes are limited by their processing difficulty, low permeability, and membrane fouling. Herein, a PEEK hollow fibre membrane (PHFM) was fabricated by melt-spinning of polyetherimide (PEI)/PEEK blends and extracting PEI. Thereafter, a hydration layer consisting of 2-hydroxylethyl acrylate (HEA) chains was constructed on the PHFM surface based on the surface-initiated atom transfer radical polymerisation method. The grafting density and grafting length of the HEA chains were modulated by varying the bromination time and ATRP reaction time, and the hydrophilicity of the resulting PHFM surface was enhanced significantly without deteriorating its original porous structure. The controllable pores and hydrated layers on the PHFM surface simultaneously improved the permeability, separation performance, and anti-fouling properties of the membrane. Under a bromination time of 6 h and an ATRP reaction time of 8 h, the water flux of the modified PHFM was enhanced by 364 %. The rejection rate of bovine serum albumin (BSA) by the modified membrane exceeded 90 %. According to the extended Derjaguin–Landau–Verwey–Overbeek theory, the improved anti-fouling performance was related to the weakened acid–base attraction between the foulants and membrane with the hydration layer. After multiple separation-washing cycles, the total fouling and irreversible fouling of the modified PHFM were reduced. The normalised water flux and BSA rejection ratio of the modified anti-fouling PHFM remained 216 % and 90 %, respectively.

Abstract 10305: A Bioresorbable Pacemaker With Transient Closed-Loop System

Introduction: Conventional temporary pacemakers with percutaneous pacing leads limit patient mobility, create risks for infections, require removal procedures following completion of therapy and demand an additional collection of wired devices to monitor the status of the patient and to provide closed-loop operation. Recently reported wireless, bioresorbable pacemakers avoid the first set of disadvantages, but they must still be paired with conventional wired-based systems for cardiac monitoring, power delivery and control. Methods: We present a bioresorbable pacemaker that combines with a wirelessly networked collection of temporary, body-integrated devices to (1) power, control, and monitor processes of cardiac stimulation, (2) track cardiopulmonary status via comprehensive, multi-modal measurements, (3) provide patient-specific multi-haptic feedback on device and physiological status, and (4) support transient operation through bioresorption and gentle removal from the skin. Results: Data captured from various locations of the body yield detailed information of patient status, across various aspects of cardiopulmonary health and physical activity. The results define autonomous rate-adaptive pacing parameters to match metabolic demand via wireless powering of the bioresorbable module. Operation is possible over extended periods to match clinical needs, enabled by advanced mechanical designs and drug eluting configurations of the battery-free, bioresorbable pacemaker platform. Replacement of the cardiac module can occur in a manner that does not disrupt continuous pacing. The skin-interfaced devices can be easily peeled away for removal after patient recovery, due to their soft, flexible construction. Conclusions: We demonstrate for the first time that a bioresorbable pacemaker with transient closed-loop system is feasible in a clinically relevant, large animal and human whole heart model. Further improvements in this technology could open doors for out of hospital temporary pacing for varying periods of time, without the need for permanent hardware.

Abstract 11979: Direct Assessment of Engineered Heart Tissue Field Potential and Contraction Dynamics Using Flexible Electronics Technology

Introduction: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) enable the study of human heart disease in a dish. However, when cultured as cells on plastic, these 2D models are immature and exhibit non-physiologic outputs. When cultured as engineered heart tissues (EHTs or 3D models), hiPSC-CMs display a more mature gene and protein profile. Although multielectrode array (MEA) platforms have been applied to 2D cultures to study the electrical properties of hiPSC-CMs, a similar approach has been lacking for EHTs. We now took advantage of technological advances in flexible electronics to create a 3D platform that allows continuous transduction of field potential and strain of human EHTs. Methods and Results: Using microfabrication techniques adapted from the semiconductor industry, custom ring-shaped flexible electronics constructs were created with 6 support posts. Each post included a microelectrode for recording electrophysiological information and a piezoresistive strain sensor for monitoring EHT contraction dynamics. These were integrated onto a flexible biocompatible polyimide support. hiPSCs were differentiated into hiPSC-CMs, and EHTs were generated by seeding 500,000 cells composed of 90% hiPSC-CMs and 10% human cardiac fibroblasts into a collagen matrix and deposited in the ring-shaped polydimethylsiloxane (PDMS) molds. Tissues were condensed over 7 days and then were transferred onto the flexible electronic scaffolds. Tissues remodeled for ~30 days and then were analyzed for contractile properties. Direct tissue stimulation and field potential measurements were obtained in real time using an Intan RHS stimulation recording system. Simultaneous recording of force of contraction relied on a calibrated Wheatstone bridge circuit. EHTs from hiPSC-CMs displayed appropriate contractile responses to pharmacologic agents. Conclusion: Although EHTs improve hiPSC-CM models by improving cellular maturity, it has been challenging to measure physiological outcomes. We now developed a prototype that simultaneously provides electrophysiologic and contractility characterization in real time of human EHTs.

A Preliminary Investigation into the Factor Structure of Two Psychological Flexibility Measures in a Sample of Community-Dwelling Older Adults

ABSTRACT Objectives Acceptance and Commitment Therapy (ACT) targets psychological flexibility and the ability to identify behavioral function in context. Properly measuring these constructs is imperative to understanding whether these processes are mechanisms of change in treatment. The current study examined the factor structure of the Comprehensive Assessment of ACT processes (CompACT) and Tacting of Function scale (TOF) in community-dwelling older adults. Methods Factor structure was examined with CFA. Eighty community-dwelling older adults completed questionnaires prior to an intervention. Results While the original 23-item, 3-factor structure of the CompACT demonstrated inadequate fit, a modified 15-item, 3-factor structure demonstrated adequate fit. The original 1-factor structure of the TOF demonstrated inadequate fit. A modified 2-factor structure of the TOF fit significantly better than the original 1-factor structure; however, this model also demonstrated inadequate fit. Conclusions Examining the factor structure of the CompACT and TOF in an older adult sample contributes to the field’s understanding of the constructs of psychological flexibility and tacting ability and to the clinical utility of these measures in an understudied sample. Clinical Implications These findings provide preliminary support for the use of a short-form version of the CompACT to measure therapeutic processes of change in community-dwelling older adults.

2.48 Resting-State Functional Connectivity Associated With Cognitive Flexibility in Youth

Cognitive flexibility is a core mental ability to adjust one’s thought and behavior in response to changing environments. Researchers have proposed the key constructs of cognitive flexibility to be attention shifting, cognitive control, and working memory. Several cortical and subcortical regions were implicated in cognitive flexibility; however, the interplay among complex functional networks remains inconclusive. Here, we aimed to investigate relevant functional networks and their integrated effect on each construct of cognitive flexibility in youth.

SPECIAL ISSUE: Do Biofeedback, Neurofeedback, and Neuromeditation Have a Role in Psychedelic-Assisted Therapies?

SPECIAL ISSUE: Do Biofeedback, Neurofeedback, and Neuromeditation Have a Role in Psychedelic-Assisted Therapies?

Skin‐Interfaced Deep‐Tissue Sensing Patch via Microneedle Waveguides (Adv. Mater. Technol. 9/2022)

Sensing Patches Real-time monitoring of muscular oxygenation can enhance post-operative care of muscular wounds and peripheral artery disease. In article number 2200468, Wubin Bai and co-workers report a strategy by integrating microneedle waveguides with a wireless optoelectronic system in a thin, flexible construction to overcome the limitation of sensing depth and enable stable, continuous monitoring of muscular oxygenation without extensive implantation procedures.

Overcoming Essentialism? Students’ Reflections on Learning Intercultural Communication Online

The fields of intercultural communication (IC) and intercultural education are in flux and the paradigmatic shift is away from essentialist approaches on culture and interculturality towards seeing IC and interculturality as flexible, fluid, contradictory, political, and ideological constructs. This study presents a virtual exchange project, a joint introductory course on IC between a Finnish university and a French university. One of the objectives of the course was to provide students with a more critical, non-essentialist perspective on interculturality. This study presents an analysis of 32 students’ texts (learning logs) that are processed qualitatively using content analysis to find answers to questions of (1) how students make sense of their experience of learning IC through multilingual online interactions, and (2) how different approaches on culture and interculturality are reflected in students’ leaning logs. The learning logs are written by participants during their six-week learning experience. The findings indicate that students gained confidence in interacting with people from diverse backgrounds and using multiple languages. How students reacted to and reflected on the more critical perspective on interculturality varied greatly, with many learning logs seeming to juggle between different approaches. The online environment was considered a major source of concern prior and at the beginning of the course, but as the course progressed it did not represent a barrier within the documented experiences. Our analysis aims to help teachers of IC to better address the needs of different learners. We also discuss the challenges and possibilities of a multilingual intercultural virtual exchange with a view to creating safe and motivating spaces for teaching and learning about interculturality.

Seismic response of an offshore wind turbine jacket structure with pile foundations

Offshore wind farm jacket structures are preferable in the deeper waters due to their flexible construction and cost-effectiveness. However, both wind tower and jacket structure are sensitive to cyclic/dynamic loading. With the rapid advancement in offshore wind farms globally, they are being constructed in the seismic regions of the world, such as offshore Taiwan, Japan, and South Korea. Therefore, there is an urgent need to understand the seismic performance of offshore wind turbines. This research investigates the behavior of an offshore wind turbine jacket structure with pile foundations subjected to earthquake loading using dynamic centrifuge testing. A jacket-equivalent wind tower model was developed and tested under the two-layered sandy soil with a dense bottom layer overlain by a loose top layer to capture the liquefaction effects under seismic loading. Using the centrifuge test data, it will be shown that with the build-up of excess pore pressure in the soil causing liquefaction under strong seismic loading, the offshore wind turbine (OWT) structure suffers severe settlements and rotations that exceed the prescribed limits. However, it was possible to restrict the settlements and rotations by having an alternative arrangement that places the pile cap on the mudline. These results highlight the need to consider vertical settlements induced by the liquefaction in addition to the restriction of the rotations at the mudline level of the foundation and the need for more research on innovative ways to mitigate liquefaction induced settlements.

Research Progress on MXene-Based Flexible Supercapacitors: A Review

The increasing demands for portable, intelligent, and wearable electronics have significantly promoted the development of flexible supercapacitors (SCs) with features such as a long lifespan, a high degree of flexibility, and safety. MXenes, a class of unique two-dimensional materials with excellent physical and chemical properties, have been extensively studied as electrode materials for SCs. However, there is little literature that systematically summarizes MXene-based flexible SCs according to different flexible electrode construction methods. Recent progress in flexible electrode fabrication and its application to SCs is reviewed according to different flexible electrode construction methods based on MXenes and their composite electrodes, with or without substrate support. The fabrication methods of flexible electrodes, electrochemical performance, and the related influencing factors of MXene-based flexible SCs are summarized and discussed in detail. In addition, the future possibilities of flexible SCs based on MXene are explored and presented.

Optimal Quasi-Orthogonal FH Sequences With Adaptive Array Receiver for Massive Connectivity in Asynchronous Multi-Cluster Networks

This paper is concerned with the enabling of massive connectivity in a multi-cluster network. In order to tackle significant amount of interference imposed by inter- and intra-cluster users, we consider a frequency-hopping (FH) system where an improved quasi-orthogonal hopping pattern, called optimal strong no-hit-zone FH sequence (SNHZ-FHS) set, is adopted in each cluster. We propose a flexible construction of SNHZ-FHS sets and derive their Hamming correlation values at different access delays. Since the maximum number of supportable users under traditional FH networks is strictly limited by the number of frequency slots, we investigate the design of a novel class of adaptive array beam-forming (BF) receiver in which SNHZ-FHS patterns (i.e., SNHZ-FH/BF) are reused over asynchronous multi-cluster uplink channels. Extensive numerical comparisons show that our proposed SNHZ-FH/BF system provides an effective means for attaining higher user capacity as well as remarkable capability of interference suppression.

Self-standing ultrathin NiCo2S4@carbon nanotubes and carbon nanotubes hybrid films as battery-type electrodes for advanced flexible supercapacitors

An electrode with flexible construction, high capacity, and battery-type Faradaic mechanism is highly required for emerging wearable and portable electronics. A class of materials with favorable architectures that store energy through the Faradaic mechanism is a fertile ground for breaking through the energy density limit of an electric double-layer-based supercapacitor. Herein, a typical battery-type electrode of NiCo2S4 composited with carbon nanotubes (CNT) has been developed via a facile two-step solution reaction. The NiCo2S4@CNT composite exhibits good energy storage ability with an ultrahigh specific capacitance of 1,123 F g−1 at 0.5 A g−1 and superior stability. After being shaped into films via alternately stacking with pure CNT films, lightweight, flexible, and self-standing NiCo2S4@CNT/CNT hybrid film electrodes are fabricated, which exhibit a high volumetric capacitance of about 443 F cm−3. All-solid-state asymmetric supercapacitors with high flexibility are assembled using the hybrid film as cathode, treated carbon cloth as anode, and polyvinyl alcohol/KOH gel as solid electrolyte. Counting the weight of the two electrode films, a high energy density of 11.7 Wh kg−1 at 1.32 kW kg−1 with good cycling stability (66% of the initial capacitance after 25,000 cycles) is accomplished, suggesting promising potential for practical application in load-leveling wearable equipment.

FRAGLER: A Fragment Recycler Application Enabling Rapid and Scalable Modular DNA Assembly.

Rapid and flexible plasmid construct generation at scale is one of the most limiting first steps in drug discovery projects. These hurdles can partly be overcome by adopting modular DNA design principles, automated sequence fragmentation, and plasmid assembly. To this end we have designed a robust, multimodule golden gate based cloning platform for construct generation with a wide range of applications. The assembly efficiency of the system was validated by splitting sfGFP and sfCherry3C cassettes and expressing them in E. coli followed by fluorometric assessment. To minimize timelines and cost for complex constructs, we developed a software tool named FRAGLER (FRAGment recycLER) that performs codon optimization, multiple sequence alignment, and automated generation of fragments for recycling. To highlight the flexibility and robustness of the platform, we (i) generated plasmids for SarsCoV2 protein reagents, (ii) automated and parallelized assemblies, and (iii) built modular libraries of chimeric antigen receptors (CARs) variants. Applying the new assembly framework, we have greatly streamlined plasmid construction and increased our capacity for rapid generation of complex plasmids.