Flexible Design Research Articles

Research on foldable two-matrix 3D braided composites: Manufacturing and bending progressive damage

Research on foldable two-matrix 3D braided composites: Manufacturing and bending progressive damage

Investigation of Mechanical Properties of Natural Fiber Reinforced Hybrid Composite

Abstract: Hybrid composite is a material composed of matrix and two or more reinforcements. Two or more reinforcements in hybrid composite replace the limitation of conventional composites by providing uniform strength to thematerial. Recently, natural fibers reinforced hybrid composites are gaining increased interest due to the encouraging properties of natural fibers such as high strength to weight ratio, low cost, no harm to environment etc. Many studies dealt with natural fibers based composite reported that the hybrid composites has the potential to replace glass fiber based composites and to reduce the weight of conventional composite. This project reports on the manufacturing of the Indian elm and Acacia fibre reinforced epoxy composite laminate as per the ASTM (American Society for Testing and Materials) Standards. This laminate consists of matrix and reinforcement. Epoxy is used as a structural matrix material which is then reinforced by Indian elm fiber, combining Acacia fibres with resin matrix results in composites that are strong, lightweight, corrosion-resistant and dimensionally stable. They also provide good design flexibility, high dielectric strength and act as inflammable materials. Their tremendous strength-to-weight and design flexibility make them ideal in structural components for the aerospace industry. In this project the Indian elm and Acacia fibre reinforced epoxy composite is manufactured into two different parts each having ratios of Indian elm and Acacia fibre to epoxy resin as 60:40, 40:60 respectively and are compared for ultimate tensile strength, impact strength, hardness strength and flexural strength of the material by conducting experiment such as tensile test, flexural test, hardness test and impact test.

Review of Oral Tablet

Abstract: Oral drug delivery is noninvasive, has a high rate of patient compliance, is easy to handle, and doesn't require any special sterile settings, it is the most popular method of administration. Nevertheless, a number of physical, biological, and pharmacological obstacles that certain medications must overcome in order to be absorbed into the systemic circulation reduce their therapeutic efficiency. The use of nanocarriers to deliver drugs orally has proven to be an effective solution to the aforementioned problems and is being explored as a potential replacement for oral medication administration. This chapter provides an overview of the latest developments in the use of nanocarriers for oral medication delivery in the treatment of different disorders. The chapter also describes how diverse nanocarrier designs and technologies improve therapeutic potential by overcoming physical, biological, and biochemical obstacles. it is easy to produce, has few sterility limitations, is less expensive, has flexible dosage form design, and has high patient compliance, oral drug delivery (ODD) is the most convenient and favored method of drug administration. However, low medication bioavailability—which is influenced by three crucial factors—is one of the difficulties associated with oral drug delivery. The other is solubility. Many mathematical models that predict the medication's rate of solubility and dissolution have been developed in order to achieve efficient drug absorption in vivo. Similarly, models that are noncellular and cellular determine permeability. Furthermore, the medication's behavior in the gastrointestinal tract (GIT) is influenced by physiological parameters, such as pH, microbial colonization, and enzymes, as well as intrinsic drug properties. A drug's dosage form is a method of getting it into a living organism. The medicine must be administered to the site of action at a rate and concentration that will maximize therapeutic benefit and minimize side effects in order to provide the intended result. Although the oral method is still commonly used, swallowing tablets and capsules can be a regular problem. As a result, numerous studies on cutting-edge drug delivery methods have been conducted. This review focuses on oral dispersible tablets, a novel approach to drug delivery systems that are currently more focused on formulation and set a new course that not only helped patients increase their level of therapy compliance.

Reskilling and rethinking work: how to build a future-fit workforce

Purpose This paper sets out why reskilling is an essential element of an effective talent strategy and outlines the key steps to successful reskilling. Design/methodology/approach A qualitative review of methodologies and practices for reskilling is presented in this paper. Findings Reskilling is an essential organisational practice allowing employers to respond effectively to turbulent business conditions. Organisations need to engage in three priority actions: strategic workforce planning, adopting flexible work design practices and developing targeted upskilling and reskilling programmes. Originality/value This is a synthesis of a variety of ideas about how to approach reskilling and reflects practices adopted by organisations.

1 × 4 nano-pixel power splitter designed using electric profile correlation coefficient monitor method

Abstract Power splitter is one of the fundamental elements in photonic integrated circuit. Among various power splitter structures, nano-pixel-based ones have attracted attention because of the flexible design capability. As there is no rigid design rule in nano-pixel layout, inverse design algorithms are employed to realize the target function. Machine-learning needs in general criteria during design process, and one typical criterial is the device excess loss. For the designing of 1×N power splitter, it is not sufficient in consideration of power valance among N output-ports. In this study, we propose an electric field profile evaluation method which evaluate the total field profile at the device facet in addition to the excess loss. We exploit the criteria including above method to design 1 × 4 power splitter. As a result, the simulated results show all four 0th order modes and the output power are 24.490%, 24.494% with excess loss of 0.1 dB..

Investigating the Application of Regression Discontinuity in the Field of International Health Economics

As one of the most significant quasi-experimental research methods, with over eight decades of development, Regression Discontinuity Design (RDD) has garnered extensive attention within the field of international health economics. It has provided robust methodological support for causal inference in research conducted within this domain. This paper provides a comprehensive review and synthesis of the foundational concepts, origins, and evolutionary trajectory of the RDD. It systematically examines the relevant studies in the domain of international health economics, discusses the strengths and limitations of the RDD, and anticipates its future applications in the same field. The aim is to support the utilization of RDD in international health economic research. On a theoretical level, it has effectively enhanced the flexibility and applicability of research designs within the domain of international health economics, augmenting the economic efficiency and external validity of studies, and offering a versatile tool for related research on a global scale. On a practical level, RD accommodates the diverse policy needs of programs across various countries and regions. It provides a more robust and reliable empirical foundation for the formulation of pertinent health policies, aiming to improve the efficiency of health resource allocation and promote equity in health outcomes.

Zero‐sum game‐based H∞ optimal finite‐time prescribed performance control for nonlinear multiagent systems with actuator faults

AbstractThis article proposes an optimal leader‐follower consensus control protocol with finite‐time prescribed performance for nonlinear multiagent systems suffering from the actuator fault based on the zero‐sum game framework. First, to guarantee the specified performance of the system within a finite time frame, a novel error transformation function (ETF) is constructed. The ETF proposed in this paper can adjust the mapping range of error transformation to achieve better error convergence performance, thereby enhancing the flexibility of the controller design. Then, to compensate for the negative impact of actuator fault, an error‐related item is separated from the optimal performance index function to design an online fault estimator, which can obtain a better error estimation accuracy. Furthermore, to lessen the need for difficult‐to‐verify persistent excitation signal in adaptive dynamic programming algorithm, both historical and real‐time data are applied to adjust the updating law of neural network weight. Moreover, it demonstrates that the signals within the closed‐loop system are bounded and the expected finite‐time prescribed performance can be ensured in the presence of faults. Finally, a numerical example of multiple single‐link robots manipulator system is executed to validate the efficacy of the developed scheme.

ERegPose: An explicit regression based 6D pose estimation for snake-like wrist-type surgical instruments.

Accurately estimating the 6D pose of snake-like wrist-type surgical instruments is challenging due to their complex kinematics and flexible design. We propose ERegPose, a comprehensive strategy for precise 6D pose estimation. The strategy consists of two components: ERegPoseNet, an original deep neural network model designed for explicit regression of the instrument's 6D pose, and an annotated in-house dataset of simulated surgical operations. To capture rotational features, we employ an Single Shot multibox Detector (SSD)-like detector to generate bounding boxes of the instrument tip. ERegPoseNet achieves an error of 1.056mm in 3D translation, 0.073rad in 3D rotation, and an average distance (ADD) metric of 3.974mm, indicating an overall spatial transformation error. The necessity of the SSD-like detector and L1 loss is validated through experiments. ERegPose outperforms existing approaches, providing accurate 6D pose estimation for snake-like wrist-type surgical instruments. Its practical applications in various surgical tasks hold great promise.

Enhancing cellular behavior in repaired tissue via silk fibroin-integrated triboelectric nanogenerators

Triboelectric nanogenerators (TENGs) have emerged as a promising approach for generating electricity and providing electrical stimuli in medical electronic devices. Despite their potential benefits, the clinical implementation of TENGs faces challenges such as skin compliance and a lack of comprehensive assessment regarding their biosafety and efficacy. Therefore, further research is imperative to overcome these limitations and unlock the full potential of TENGs in various biomedical applications. In this study, we present a flexible silk fibroin-based triboelectric nanogenerator (SFB-TENG) that features an on-skin substrate and is characterized by excellent skin compliance and air/water permeability. The range of electrical output generated by the SFB-TENG was shown to facilitate the migration and proliferation of Hy926, NIH-3T3 and RSC96 cells. However, apoptosis of fibroblast NIH-3T3 cells was observed when the output voltage increased to more than 20 V at a frequency of 2 Hz. In addition, the moderate electrical stimulation provided by the SFB-TENG promoted the cell proliferation cycle in Hy926 cells. This research highlights the efficacy of a TENG system featuring a flexible and skin-friendly design, as well as its safe operating conditions for use in biomedical applications. These findings position TENGs as highly promising candidates for practical applications in the field of tissue regeneration.

Design and Validation of the Trailing Edge of a Variable Camber Wing Based on a Two-Dimensional Airfoil

Variable camber wing technology stands out as the most promising morphing technology currently available in green aviation. Despite the ongoing advancements in smart materials and compliant structures, they still fall short in terms of driving force, power, and speed, rendering mechanical structures based on kinematics the preferred choice for large long-range civilian aircraft. In line with this principle, this paper introduces a linkage-based variable camber trailing edge design approach. Covering coordinated design, internal skeleton design, flexible skin design, and drive structure design, the method leverages a two-dimensional supercritical airfoil to craft a seamless, continuous two-dimensional wing full-size variable camber trailing edge structure, boasting a 2.7 m span and 4.3 m chord. Given the significant changes in aerodynamic load direction, ground tests under cruise load utilize a tracking-loading system based on tape and lever. Results indicate that the designed single-degree-of-freedom Watt I mechanism and Stephenson III drive mechanism adeptly accommodate the slender trailing edge of the supercritical airfoil. Under a maximum cruise vertical aerodynamic load of 17,072 N, the structure meets strength requirements when deflected to 5°. The research in this paper can provide some insights into the engineering design of variable camber wings.

From virus to immune system: Harnessing membrane-derived vesicles to fight COVID-19 by interacting with biological molecules.

Emerging and re-emerging viral pandemics have emerged as a major public health concern. Highly pathogenic coronaviruses, which cause severe respiratory disease, threaten human health and socioeconomic development. Great efforts are being devoted to the development of safe and efficacious therapeutic agents and preventive vaccines to combat them. Nevertheless, the highly mutated virus poses a challenge to drug development and vaccine efficacy, and the use of common immunomodulatory agents lacks specificity. Benefiting from the burgeoning intersection of biological engineering and biotechnology, membrane-derived vesicles have shown superior potential as therapeutics due to their biocompatibility, design flexibility, remarkable bionics, and inherent interaction with phagocytes. The interactions between membrane-derived vesicles, viruses, and the immune system have emerged as a new and promising topic. This review provides insight into considerations for developing innovative antiviral strategies and vaccines against SARS-CoV-2. First, membrane-derived vesicles may provide potential biomimetic decoys with a high affinity for viruses to block virus-receptor interactions for early interruption of infection. Second, membrane-derived vesicles could help achieve a balanced interplay between the virus and the host's innate immunity. Finally, membrane-derived vesicles have revealed numerous possibilities for their employment as vaccines.

A compact tri-notched flexible UWB antenna based on an inkjet-printable and plasma-activated silver nano ink

The rapid development of ultrawideband (UWB) communication systems has resulted in increasing performance requirements for the antenna system. In addition to a wide bandwidth, fast propagation rates and compact dimensions, flexibility, wearability or portability are also desirable for UWB antennas, as are excellent notch characteristics. Although progress has been made in the development of flexible/wearable antennas desired notch properties are still rather limited. Moreover, most presently available flexible UWB antennas are fabricated using environmentally not attractive subtractive etching-based processes. The usage of facile additive sustainably inkjet printing processes also utilizing low temperature plasma-activated conductive inks is rarely reported. In addition, the currently used tri-notched flexible UWB antenna designs have a relatively large footprint, which poses difficulties when integrated into miniaturized and compact communication devices. In this work, a silver nano ink is used to fabricate the antenna via inkjet printing and an efficient plasma sintering procedure. For the targeted UWB applications miniaturized tri-notched flexible antenna is realized on a flexible polyethylene terephthalate (PET) substrate with a compact size of 17.6 mm × 16 mm × 0.12 mm. The antenna operates in the UWB frequency band (2.9–10.61 GHz), and can shield interferences from WiMAX (3.3–3.6 GHz), WLAN (5.150–5.825 GHz) and X-uplink (7.9–8.4 GHz) bands, as well as exhibits a certain of bendability. Three nested "C" slots of different sizes were adopted to achieve notch features. The simulation and test results demonstrate that the proposed antenna can generate signal radiation in the desired UWB frequency band while retaining the desired notch properties and having acceptable SAR values on-body, making it a viable candidate for usage in flexible or wearable communication transmission devices. The research provides a facile and highly efficient method for fabricating flexible/wearable UWB antennas, that is, the effective combination of inkjet printing processing, flexible substrates, low temperature-activated conductive ink and antenna structure design.

Dynamically stable radiation pressure propulsion of flexible lightsails for interstellar exploration

Meter-scale, submicron-thick lightsail spacecraft, propelled to relativistic velocities via photon pressure using high-power density laser radiation, offer a potentially new route to space exploration within and beyond the solar system, posing substantial challenges for materials science and engineering. We analyze the structural and photonic design of flexible lightsails by developing a mesh-based multiphysics simulator based on linear elastic theory. We observe spin-stabilized flexible lightsail shapes and designs that are immune to shape collapse during acceleration and exhibit beam-riding stability despite deformations caused by photon pressure and thermal expansion. Excitingly, nanophotonic lightsails based on planar silicon nitride membranes patterned with suitable optical metagratings exhibit both mechanically and dynamically stable propulsion along the pump laser axis. These advances suggest that laser-driven acceleration of membrane-like lightsails to the relativistic speeds needed to access interstellar distances is conceptually feasible, and that their fabrication could be achieved by scaling up modern microfabrication technology.

A case study on scenario-based optimization for axle load survey data selection for flexible pavement design in Vietnam

The unique traffic patterns in Vietnam, characterized by a mix of vehicle types, axle configurations, and overloading, pose challenges to current flexible pavement design methods. This study investigates how selecting different vehicle axle load survey data scenarios impacts the accuracy of pavement design and rehabilitation for roads in Vietnam. Evaluation of various data selection methods and their influence on pavement response using the current flexible pavement calculation procedure in Vietnam. By comparing the pavement design criteria calculated under each scenario, this research aims to provide clear guidelines for engineers choosing appropriate axle load data for pavement design. This, in turn, will lead to the design and maintenance of more durable and sustainable pavements, ultimately promoting a more efficient and resilient transportation infrastructure in Vietnam. The research approach involves analyzing various axle load survey data scenarios, including those representing typical traffic conditions, overloaded vehicles, and specific vehicle types. The calculated pavement responses under each scenario are then compared to assess the impact of data selection on design outcomes. This study's findings are expected to provide valuable insights for pavement engineers in Vietnam, enabling them to select appropriate axle load data for accurate pavement design and rehabilitation. This will contribute to building more durable and sustainable road infrastructure, resulting in a more efficient and resilient transportation network

Advancing Transdermal Delivery by Zn/Ag-Electrode-Printed Iontophoretic Patch with Self-Generating Microcurrents

This study aimed to evaluate Zn/Ag-electrode-printed patches for the transdermal delivery of small molecules through iontophoresis. The Zn/Ag-electrode-printed patches interact with biological liquid electrolytes and generate suitable microcurrents for the iontophoretic delivery of small molecules across the skin. In fluorescein permeation studies, Zn/Ag-electrode-printed patches increased the transdermal depth of fluorescein into the dermis, while the permeation of fluorescein was limited when Zn/C-electrode-printed patches were tested. Further permeation experiments were conducted with 3D skin models, which showed a similar trend to the above, indicating that Zn/Ag-electrode-printed patches had a higher penetration rate compared to the blank. Studies using acetyl hexapeptide-8 as a peptide drug model and sodium ascorbyl phosphate (SAP) as a hydrophilic derivative of ascorbic acid showed that the iontophoretic patch with Zn/Ag electrodes promoted more penetration of drugs than unprinted patches. The permeation of SAP exhibited a two-phase profile with a relatively rapid permeation followed by a sustained, slower permeation. The permeation of acetyl hexapeptide-8 was slower due to its higher molecular weight, but the iontophoretic patch increased the permeation up to 1.5 times more than the unprinted patch. The microcurrent generated by the patch drives the transport of small molecule components through the skin, for the controlled and efficient delivery of therapeutic agents. The flexible design, efficient microcurrent generation, and stable electrodes make the Zn/Ag-electrode-printed patch a promising tool for transdermal drug delivery.

Understanding individual experiences with stick-built and modular cleanrooms: Lessons learned and a call to action.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. The purpose of this study was to assess the real-world experiences of cleanroom managers and specialists who have designed, installed, and maintained stick-built and/or modular cleanrooms, delineate the advantages and disadvantages of each type of cleanroom, and gather sterile compounding cleanroom design and installation advice and lessons learned. This study was conducted via surveys and semistructured interviews of individuals with cleanroom experience in the previous 5 years. Qualitative analyses were conducted on participants' survey and interview responses to assess their satisfaction with each type of cleanroom and to determine what they perceive to be the pros and cons of each type based on their own experiences. Key lessons learned and advice from these individuals were also extracted from their survey and interview responses. Fourteen individuals from 13 US states completed the survey; twelve participated in follow-up interviews. Fifty percent of the participants (n = 7) had installed 5 or more cleanrooms in the previous five years and over half (n = 8; 57%) had 7 or more years of cleanroom experience. The average satisfaction scores for each type of cleanroom, on a 1 to 10 scale, was 5.3 for stick-built (n = 11) and 9.3 for modular (n = 4). The pros of stick-built cleanrooms included greater design and material flexibility and lower up-front costs. The pros of modular cleanrooms included the cleanroom experience and expertise of modular vendors, quick and easy installations, guaranteed certification, and high-quality and durable design features and materials. Additionally, modular cleanrooms had fewer long-term maintenance issues, greater long-term flexibility, and lower indirect and long-term costs than stick-built cleanrooms. Key pieces of advice from the participants included the following: do your homework before beginning a cleanroom project; make sure heating, ventilation, and air conditioning system(s) and air handlers are adequate for your needs; and remember that the ultimate purpose of a quality cleanroom is patient safety. Participants also advocated for industry-wide cleanroom standards that go beyond USP regulations. The findings of this study confirm many of the purported pros and cons of each type of cleanroom, with further insight gained into the relative quality and costs of each type. Modular cleanrooms were considered by most participants to be a better long-term option, based on quality and lifetime costs, if feasible to install. Study participants also emphasized that designing and installing pharmacy cleanrooms is a complex and time-intensive process that often comes with a steep learning curve. While there are federal and state cleanroom standards available and consultants for hire, a comprehensive resource or manual that could provide guidance, insight, and collective lessons learned on cleanroom design and installation is needed.

Chaos generation of superconducting quantum bits coupled with LC resonant circuits

The dynamics of chaos have been widely used in nonlinear science, such as neural networks, extreme event statistics, and the biophysics of chaos self-organization. Superconducting qubits are artificial atoms based on the Josephson junction structure of nonlinear superconducting devices, offering high design flexibility and ease of coupling and control. In this paper, the generation of chaos through the coupling between superconducting qubits and LC resonant circuits is investigated. By varying the ratio of Josephson energy to charge energy, the coupling coefficient, and the energy of the external driving field, the generation and control of chaos within the system are numerically analyzed. This study provides theoretical support for parameter selection ensuring the confidentiality and fidelity of quantum information transmission based on the chaotic dynamics of superconducting qubits.

On-chip silicon photonic nanohole metamaterials enabled high-density waveguide arrays

High-density silicon waveguide arrays manufactured on a complementary metal-oxide-semiconductor (CMOS)-foundry platform hold great promise for optical information processing and photonic integration. However, evanescent waves arising from nanoscale confinement would cause significant optical crosstalk in waveguide arrays, which remains a vital issue in various applications. Here, by utilizing silicon photonic nanohole metamaterials, we propose a scheme to greatly suppress the crosstalk in the devices and then demonstrate ultra-compact low-crosstalk waveguide arrays. For a 100-µm-long waveguide array at a half-wavelength pitch, low crosstalk of −19 dB can be obtained in a wide range of wavelengths (1500 nm–1580 nm). In the experimental demonstrations, our approach exhibits the ability to suppress the crosstalk over a broad bandwidth without substantially increasing the propagation loss as well as the promising design flexibility, which shall pave the way for metamaterials enabled high-density waveguide arrays.

Living on Site While Renovating; Flexible Instructional Design of Post-Graduate Medical Training.

Developing theoretical courses for post-graduate medical training that are aligned to current workplace-based learning practices and adaptive to change in the field is challenging, especially in (sub) specialties where time for re-design is limited and needs to be performed while education continues. An instructional design method was applied based on flexible co-design to improve post-graduate theoretical courses in child and adolescent psychiatry (CAP) in the Netherlands. In four phases over a period of three years, courses were re-designed at a national level. Once common vision and learning goals were agreed upon and the prototype was developed (phases 1 and 2), the first courses could be tested in daily practice (phase 3). Phase 4 refined these courses in brief iterative cycles and allowed for designing additional courses building on and adding to previous experiences in brief iterative cycles. The resulting national theoretical courses re-allocated resources previously spent on a local level using easily accessible online tools. This allowed trainees to align content with their clinical rotations, personal preferences and training schedules. The development of theoretical courses for post-graduate medical training in smaller medical (sub-)specialties with limited resources may profit from a flexible instructional design method. We consider the potential merit of such a method to other medical specialties and other (inter-)national efforts to develop theoretical teaching courses. A longer-term implementation evaluation is needed to show to what extent the investment made in the re-design proves to be future-proof and enables rapid adaptation to changes in the field.

Manufacturing studies of a polymeric/composite heart valve prosthesis

AbstractCurrent transcathether heart valves rely on metal mesh stents, resulting in discontinuous stent‐leaflet interfaces that introduce stress concentrations, reducing valve lifetime. This work aims to investigate non‐conventional methods to create a fully polymeric transcatheter heart valve, exhibiting a quasi‐continuous interface with hemocompatible leaflets with high durability potential. Polyetheretherketone (PEEK) is of particular interest as a cardiovascular material due to hemocompatibility and mechanical resilience, highly relevant for catheter delivered valves. For increased reproducibility and design freedom, an autoclave process was used to manufacture thin‐ply PEEK composite stents. We demonstrated that a suitable membrane material during manufacturing is essential to evenly distribute pressure around the stent. Meanwhile, a modified vacuum forming process was used to simultaneously form and attach PEEK leaflets to the stent using a heated mold. This simple and robust method enables rapid manufacturing of an integral PEEK‐based valve design, resulting in improved stent‐leaflet bonding, demonstrating an alternative to conventional dip‐coating. The customized vacuum forming causes a controlled annealing effect in semicrystalline materials such as PEEK. Processing PEEK leaflets at higher mold temperatures results in higher crystallinity, elastic modulus, and bond strength. These processes enable greater design flexibility and promote composite materials for use in heart valve devices.Highlights Developed manufacturing processes for PEEK‐based heart valve implants. Proof of concept for thermoforming of semi‐crystalline PEEK leaflets. Demonstrated effect of processing temperature on valve mechanical properties. Autoclave processing and vacuum forming enable new heart valve designs.