Malleable Material Research Articles

Thermoplastic and thermoset polymer matrix composites reinforced with bismuth oxide as radiation shielding materials

Polymer composites reinforced with heavy metals have wide applications in the nuclear industry as radiation shielding materials against emitted radiation from nuclear equipment. In this study, considering bismuth oxide as reinforcement, various polymers including thermoplastic polymers, such as high-density polyethylene, low-density polyethylene, polypropylene, polyvinyl acetate, polymethyl methacrylate, and thermosetting epoxy resin have been considered as matrices. After preparing various samples of polymer composites loaded with 60 % by weight of bismuth oxide, some physical, mechanical, and radiation shielding properties (neutron and gamma attenuation coefficients) of these polymer composites have been measured and compared with each other. First, the density of the samples was measured, and the response of these samples to varying compressive force was investigated. The stress-strain diagrams of composites with different matrices were compared. Subsequently, the linear and mass attenuation coefficients of the composites were measured over a wide range of energies (32–1480 keV) against direct and collimated beams from various standard gamma-ray sources (134Cs, 60Co, 154Eu, 133Ba, and 22Na) using an HPGe detector. A collimated beam from an Am–Be source was utilized to measure and compare the attenuation properties of the composite samples against neutron flux. Furthermore, the properties of the composites against neutron and gamma radiation were calculated using the MCNP Monte Carlo code over a broad energy range, and the results were compared and validated with the experimental data. The comparison of the calculated and measured results shows reasonable agreement. The results indicate that in situations where high attenuation properties coupled with high strength are desired, polymeric composites with an epoxy matrix can be considered as radiation shielding materials. If the use of flexible and malleable material is required, such as for reactor piping shielding or the fabrication of protective gloves and clothing in a radiation environment, among the polymers studied, polyvinyl acetate is a more suitable matrix.

Flexible Paper and Cloth Substrates With Conductive Laser Induced Graphene Traces for Electroanalytical Sensing, Energy Harvesting and Supercapacitor Applications

Flexible technology is the new era of technological innovations in a variety of applications such as sensors and energy harvesting. Development of conductive pathways on malleable materials, in an economic manner, plays a significant role in the field of wearable bioelectronics. In this work, a simple approach to fabricate flexible paper and textile based micro-devices has been discussed. The conductive traces on the substrates were created using an optimized laser ablation technique on the material coated substrate to form laser induced graphene (LIG) both on paper and cloth which as conductivity of 825 S/m and 720 S/m respectively. The proposed procedure is utilized as a conductive platform in developing three important designs each for biological sensing, energy harvesting and energy storage applications. From analysis it can seen that, pLIG had better catalytic performances by delivering high power density of 4.5 μW/cm2, better LOD 1.31 μM and improved areal capacitance 15 mF/cm2 Finally, the challenges and the future prospects for developing these novel wearable devices for numerous applications have been enumerated.

The Two Forms of Legal Time: Pierre Legendre’s “La Durée Poignardée”: Remarques sur la Structure et le Temps

AbstractIn his Leçons VII (Le désir politique de dieu) Pierre Legendre applies the idea or expression of ‘instituting time’ (‘instituer le temps’), that is, working with time as a malleable material, but at the same time conceptualising time as dogmatic time, especially in the interpretation of law. As an example of this concept he refers to the English Common Law, a ‘style’ of ‘governing by solving cases’. This text will analyse the notion of two times of law—inaugural/mythological and historical—and how it applies to Common Law judgments, as well as to Institutional Writers that are characteristic of Scots Law in particular.

Satisfaction of Health Professionals Regarding the Short Binasal Prong Used as a Non-Invasive Ventilation Interface in Neonatology.

To evaluate the health professionals' satisfaction regarding the short binasal prong used in Neonatal Intensive Care Units (NICU), evaluate the difficulties related to its use, and present possible improvements in the design of this device. Observational, cross-sectional study with prospective data collection carried out in the NICU of a public hospital in southern Brazil. This research was presented into two stages. In the first stage, the Quebec User Evaluation of Satisfaction with Assistive Technology was applied with 90 health professionals to evaluate the satisfaction regarding the short binasal prong. In the second stage, the health professional's experiences and difficulties in using the binasal prongs in 14 newborns (NBs) that required non-invasive ventilation was collected. The short binasal prongs used was the Fanem® brand and the CPAP circuit was Gabisa Medical International (GMI®). Finally, improvements and recommendations were presented to optimize the device's design. The mean score of the health professionals' satisfaction with short binasal prongs was 3.8 ± 0.6. Ease of adjustment (3.27) and dimensions (3.62) variables had the worst scores. The main difficulties pointed out by health professionals were: circuit disconnection (57.1%), the size of the prong did not correspond to NBs' anatomical characteristics (35.7%), air leakage (21.4%), and difficulty in fixing and positioning the prong in the NB (14.28%). The improvements suggested were: appropriate prong sizes based on the anatomical characteristics of the NBs; adjustable distance between insertion and base catheters; manufactured with malleable material, however not easily foldable; curved and adjustable insertion catheters and functional system of tracheas' connection. The dissatisfaction of health professionals with the dimensions and prongs adjustments and the difficulties faced in clinical practice indicate the need for improvements in these interfaces. The recommendations presented in this study may contribute to optimizing the design of the binasal prong in the future.

HYGROSCOPIC CHARACTERIZATION OF EARTH BRICKS MADE FROM LATERITE AND CLAY OF SENEGAL

Earth is the main raw material most used in building construction in Africa and particularly in Senegal. It is a particularly malleable material, easy to handle, from which hard bricks (unfired or fired) can be made. Thus for a good prediction of the mechanical and thermal behavior of a material, it is important to determine its hygroscopic properties. This is why our study focuses on the hygroscopic characterization of earth materials based on laterite and clay. We are mainly interested in the study of adsorption and desorption isotherms by water vapor. The adsorption and desorption isotherm curves of the samples were determined by a volumetric method using the Belsorp Aqua3 apparatus. The measurement results showed that the earth materials are hygroscopic materials. Furthermore, unfired earth materials adsorb more moisture than fired earth materials.

S2510 Limitations of Endoscopic Tools for Foreign Body Retrieval: A Case of Massive Ferromagnet Ingestion

Introduction: Esophagogastroduodenoscopy (EGD) remains the standard of care for foreign body (FB) retrieval. The decision to pursue endoscopic intervention is based on multiple considerations including the probability of passage of the FB, the risk of potential injury caused by ingestion of the foreign body, and the risk of potential injury caused by performing the intervention. We present a case of FB ingestion resulting in practically impossible endoscopic retrieval. We also highlight endoscopic cues that should prompt a gastroenterologist to consider surgical evaluation in high-risk cases. Case Description/Methods: A 49-year-old man with schizoaffective disorder and a history of multiple ingestions of foreign bodies presented to the hospital for vomiting and diarrhea for 4 days. An abdominal x-ray revealed a large radiopaque structure that conformed to the shape of the stomach in the gastric region [Figure 1a]. EGD revealed multiple large consolidated ovoid masses of gray metal in the gastric body and antrum [Figure 2a]. Endoscopic retrieval was attempted using a large cold snare, which could not be wrapped around or secured around the FB without slipping upon closure. A Roth net was tried with the same unsuccessful result. Bites of the FB using rat-tooth forceps slightly deteriorated the mass and the foreign body material impeded the full-closing of the jaws of the forceps so that the forceps could not be retrieved through the working channel. The malleable material then had to be irrigated and scraped off to allow for reuse. Due to the large size of the FB and small space in the stomach for gastroscope maneuverability and the presence of multiple scattered large and deeply cratered ulcers along the gastric wall, the procedure was aborted to avoid perforation [Figure 2b]. The patient was referred for surgical intervention and soon thereafter underwent FB removal via partial gastrectomy with gastric reconstruction [Figure 1b]. The recovered FB weighed 2,885 grams and measured 32 x 31 x 1.5 cm Discussion: Care should be practiced when planning and executing the retrieval of foreign bodies. The type, size, and location of the FB, the patient’s anatomy, the presence of deep ulceration and the risk of organ perforation are important considerations for the endoscopist. Surgical intervention should be considered when the risk of perforation with endoscopic intervention is high and/or endoscopic attempts at retrieval have been unsuccessful after practically exhausting the endoscopic tools available.Figure 1.: 1a: CT scan without contrast on admission Figure 1b: CT scan without contrast post-surgery. Figure 2a: Foreign body in gastric body Figure 2b: Foreign body with ulcers in gastric body.

Strain-Driven Optical, Electronic, and Mechanical Properties of Inorganic Halide Perovskite CsGeBr3

Of late, inorganic perovskite material, especially the lead-free CsGeBr3, has gained considerable interest in the green photovoltaic industry due to its outstanding optoelectronic, thermal, and elastic properties. This work systematically investigated the strain-driven optical, electronic, and mechanical properties of CsGeBr3 through the first-principles density functional theory. The unstrained planar CsGeBr3 compound demonstrates a direct bandgap of 0.686 at its R-point. However, incorporating external biaxial tensile (compressive) strain can be tuned the bandgap lowering (increasing) to this perovskite. Moreover, due to the increase of tensile (compressive) strain, a red-shift (blue-shift) behavior of the absorption-coefficient and dielectric function is found in the photon energy spectrum. Strain-induced mechanical properties also reveal that CsGeBr3 perovskites are mechanically stable and highly malleable material and can be made suitable for photovoltaic applications. The strain-dependent optoelectronic and mechanical behaviors of CsGeBr3 explored here would benefit its future applications in optoelectronics and photovoltaic cells design.

The Atemporal Event

The COVID pandemic has prompted many people to reconsider their previous living and working rhythms and to consider alternatives. We believe that the global enslavement to the standardised time of clocks and calendars has had a negative impact on us individually, socially, and environmentally. We aim, therefore, to change perceptions of time by helping people step outside societal time, treating time instead as a malleable material that can be stretched and moulded. This exposition describes our process, outcomes, and analysis in staging an event using an alternative approach based on natural and material time processes specifically related to the body and the external day/night cycle driven by light colour and intensity. In a twenty-four-hour event in London designed around chronobiological phases, we investigated our research question of how to change perceptions of time by treating it as a malleable material. We discovered that treating time as a malleable material necessitates first stepping outside of the clock-time system: in our case, using daylight and bodily chronobiological phases as alternative time-givers. Dialogues using linguistic and non-linguistic means between ourselves, our collaborators and participants, as well as with our tools and materials, resulted in treating time as place, and places and things in temporal terms. We discovered that time is not only stretchable but can take different shapes and qualities, with multiple times existing alongside each other, by 'programming' actions and activities through performance, rhythm, and materiality. Our research focuses on the broader issue of the ‘time crisis’ as identified by sociologists, chronobiologists, and philosophers, as a result of acceleration processes driven by digital technologies and contemporary 24/7 societal norms. We address this by bringing together Helga's research on ‘uchronia’ (temporal utopia or non-time) and Kevin's anthropological perspective on designing embodied experiences.

Robotic Plaster Spraying: Crafting Surfaces with Adaptive Thin-Layer Printing.

Embedded in a long tradition of craftsmanship, inside or outside building surfaces, is often treated with plaster, which plays both functional and ornamental roles. Today, plasterwork is predominantly produced through rationalized, time-, and cost-efficient processes, used for standardized building elements. These processes have also gained interest in the construction robotics field, and while such approaches target the direct automation of standardized plasterwork, they estrange themselves from the inherent qualities of this malleable material that are well known from the past. This research investigates the design potentials of robotic plaster spraying, proposing an adaptive, thin-layer vertical printing method for plasterwork that aims to introduce a digital craft through additive manufacturing. The presented work is an explorative study of a digitally controlled process that can be applied to broaden the design possibilities for the surfaces of building structures. It involves the spraying of multiple thin layers of plaster onto a vertical surface to create volumetric formations or patterns, without the use of any formwork or support structures. This article describes the experimental setup and the initial results of the data collection method involving systematic studies with physical testing, allowing to develop means to predict and visualize the complex-to-simulate material behavior, which might eventually enable to design with the plasticity of this material in a digital design tool.

Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys.

In human-made malleable materials, microdamage such as cracking usually limits material lifetime. Some biological composites, such as bone, have hierarchical microstructures that tolerate cracks but cannot withstand high elongation. We demonstrate a directionally solidified eutectic high-entropy alloy (EHEA) that successfully reconciles crack tolerance and high elongation. The solidified alloy has a hierarchically organized herringbone structure that enables bionic-inspired hierarchical crack buffering. This effect guides stable, persistent crystallographic nucleation and growth of multiple microcracks in abundant poor-deformability microstructures. Hierarchical buffering by adjacent dynamic strain-hardened features helps the cracks to avoid catastrophic growth and percolation. Our self-buffering herringbone material yields an ultrahigh uniform tensile elongation (~50%), three times that of conventional nonbuffering EHEAs, without sacrificing strength.

An Experimental Study of Improvised Portable Manual Rebar Bender

Objective: To design, fabricate and evaluate the new features of a portable manual rebar bender, a Hand Tool that is used for bending rebar and other malleable materials. Methods: The researcher improves on the previously available portable manual rebar bender. Experts assessed the acceptability of this bender in terms of design and portability. Furthermore, as previously stated, the study significantly improves the usefulness of the inexpensively produced bending machine for reinforcing concrete with negligible human force. Findings: The device created has a valuable impact on the construction industry’s human force due to its affordability and marketability. Also,the present tools guaranteed strength, durability, and lightness in weight. Furthermore, the portable manual rebar is made of different elements such as a center axle, stationary backup roller, and sleeve. The results after ten trials showed that the portable manual rebar bender could finish 9 mm, 20mm, and 12 mm stirrup at an average of 24.3 seconds, 26.3 seconds, and 27.7 seconds, respectively. Additional results from seven to ten trials showed the bending time for 24 seconds stirrup for 9mm, 26 seconds stirrups for 10 mm, and 28 seconds stirrup for 12 mm. Furthermore, after a series of ten trials, the instrument achieved an accurate angle bent of 90 degrees. The M= 4.77 and 4.82 are very acceptable in terms of design and portability tools based on the evaluators’ rating. Novelty: The design is novel in terms of cost, portability, and efficiency. The device can be a great help in the structures and buildings. Furthermore, the construction industry will use the portable manual rebar bender to build houses and other local infrastructure to test its effectiveness. Then, the researcher is encouraged to engage in another research to try the innovation. Keywords: Improvised; Innovative; Locally made; Device; Bender

Assessment of innovative dented sheet liner on the improvement of hydraulic properties of pervious concrete pile

The Pervious Concrete Pile (PCP) is a technique that has emerged as an innovative method to improve radial consolidation and the bearing capacity of soft soils. The PCP, a stiffer vertical column (pile), has voids on the surface that accelerate the radial consolidation and eventually improve soft soils' bearing capacity. Since the PCP is stiffer material, the performance does not depend on the confined soil, unlike other drains. As the rate of radial consolidation hinges on the drain's hydraulic conductivity, ensuring the permeability of PCP along its total length is essential. An innovative method of dented sheet liner has been introduced in this study to improve the hydraulic conductivity of PCP. This method was introduced to create surface roughness and regular voids along the length of PCP. Malleable material like aluminium has been dented with specified patterns as a liner on the inner surface and introduced along with conventional formwork, which shall be removed after the concrete's final setting time. A series of laboratory experiments such as compressive strength, split tensile strength, porosity, and falling head permeability tests were performed on PCP cast using dented sheet liners. The results were compared with the conventional PCP properties to establish the efficiency of dented sheet liner in improving the hydraulic conductivity of pervious concrete. The results show that using dented sheet liners, the hydraulic properties porosity and permeability of PCP have been increased up to 22.5% and 79%, respectively, with minimum reduction in the strength parameters.

A three-dimensional printed customized bolus: adapting to the shape of the outer ear.

The skin-sparing effect of megavoltage-photon beams in radiotherapy (RT) reduces the target coverage of superficial tumours. Consequently, a bolus is widely used to enhance the target coverage for superficial targets. This study evaluates a three-dimensional (3D)-printed customized bolus for a very irregular surface, the outer ear. We fabricated a bolus using a computed tomography (CT) scanner and evaluated its efficacy. The head of an Alderson Rando phantom was scanned with a CT scanner. Two 3D boluses of 5- and 10-mm thickness were designed to fit on the surface of the ear. They were printed by the Stratasys Objet260 Connex3 using the malleable "rubber-like" photopolymer Agilus. CT simulations of the Rando phantom with and without the 3D and commercial high density boluses were performed to evaluate the dosimetric properties of the 3D bolus. The prescription dose to the outer ear was 50 Gy at 2 Gy/fraction. We observed that the target coverage was slightly better with the 3D bolus of 10mm compared with the commercial one (D98% 98.2% vs. 97.6%).The maximum dose was reduced by 6.6% with the 3D bolus and the minimum dose increased by 5.2% when comparing with the commercial bolus. In addition, the homogeneity index was better for the 3D bolus (0.041 vs. 0.073). We successfully fabricated a customized 3D bolus for a very irregular surface. The target coverage and dosimetric parameters were at least comparable with a commercial bolus. Thus, the use of malleable materials can be considered for the fabrication of customized boluses in cases with complex anatomy.

Soft Robotics: Research, Challenges, and Prospects

The soft robot is a kind of continuum robot, which is mainly made of soft elastic material or malleable material. It can be continuously deformed in a limited space, and can obtain energy in large bending or high curvature distortion. It has obvious advantages such as high security of human-computer interaction, strong adaptability of unstructured environment, high driving efficiency, low maintenance cost, etc. It has wide application prospects in the fields of industrial production, defense military, medical rehabilitation, exploration, and so on. From the perspective of the bionic mechanism, this paper introduces the soft robots corresponding to insect crawling, snake crawling, fish swimming, elephant trunk, arm, etc. According to different driving modes, the soft robots can be classified into pneumatic-hydraulic driven, intelligent material driven, chemical reaction driven, and so on. The mechanical modeling, control strategy, material, and manufacturing methods of soft robot are summarized, and the application fields of soft robot are introduced. This paper analyzes the main challenges faced by the research on the key technologies of soft robots, summarizes and analyzes them, and puts forward the prospects for the future research of soft robots. The development trend of the future is to develop the soft robot with the characteristics of micro-scale, rigid-flexible coupling, variable stiffness, multi-functional, high integration, and intelligence of driving sensor control.

Growth and study of 4-sulfobenzenaminium potassium dihydrogenphosphate for mechanical, dielectric and photonics applications

Abstract This article describes the growth and characterization of 4-sulfobenzenaminium potassium hydrogen phosphate (SPH) sulphanilic acid with potassium dihydrogen phosphate (KDP) doped semi-organic single crystals. The crystal was grown by the slow evaporation method. Examination of the crystalline nature of the sample was carried out by single crystal X-ray diffraction and it confirmed that the sample crystallizes in orthorhombic structure in the centrosymmetric space group P212121. The optical transmittance behavior was tested by UV-Vis spectral analysis. FT-IR spectral investigations have been carried out to indicate the presence of functional groups. The chemical structure of the compound was established by 1H and 13C NMR spectra. The SHG efficiency of the powdered SPH crystal is around 1.7 times that of pure KDP. The grown crystal was stable up to 270 °C as observed from TGA and DTA curves. The microhardness test was carried out to study the load dependency of hardness. The result of this study indicates that SPH crystal is a malleable material. From the hardness values, the stiffness constant and yield strength were calculated. The dielectric response of the novel crystal was studied in the frequency range of 50 Hz to 5 MHz at various temperatures. By employing FE-SEM, the surface morphology and the particle size of the crystal were assessed.

Crafting plaster through continuous mobile robotic fabrication on-site

Industrialization of architectural components and technological advances have had a significant impact on how we design and build. These developments, resulting in mass-produced and panelized architectural components, have rationalized building construction. However, they often do not reveal the true potential of the inherent qualities of malleable materials. This research investigates the bespoke design potentials of combining a cementitious plaster, with a robotic spraying and forming process, and proposes an adaptive thin-layer additive manufacturing method for plasterwork. Research goals address an on-site construction system that is capable of performing continuous robotic plaster spraying on building elements. To support the understanding of the complex-to-simulate material behavior in this process, systematic studies and physical testing are proposed to be conducted to collect empirical knowledge and data. The goal is to explore bespoke surface qualities, with minimal waste, moving away from the modular and standardized form of the material. The paper presents the preliminary results and findings of the method that aims addressing the challenge of an adaptive construction system capable of performing continuous fabrication, for which mobile robots are proposed to be deployed.

Insights into fracture mechanisms in nanoporous gold and polymer impregnated nanoporous gold

Nanoporous metals have favourable characteristics for many applications. These materials have, however, failed to show suitable attributes in tension: showing an extremely weak and brittle response. This issue has been addressed through the impregnation of a polymer constituent into the nanoporous ligament network, creating a strong and malleable material in both tension and compression. In this work, this improvement is investigated by comparing nanoporous gold and its polymer filled nanocomposite counterpart using computational microspecimen compact-tensile tests. We examine crack initiation and propagation within these materials. The micromechanical response is also explored to reveal the influence of the polymer impregnation on fracture mechanisms. It is shown that, in agreement with the findings in the literature, the failure of a few gold ligaments in nanoporous gold leads to the complete failure of the material with a relatively small resistance to failure and a characteristically brittle fracture. Polymer impregnation, on the other hand, effectively delays the complete material failure as the polymer stabilizes the individual ligaments. This results in a significantly increased ductility under tension which is vital for it to be considered for use in structural applications.

Production and closed-loop recycling of biomass-based malleable materials

The search of biomass-based substitutes for fossil-based plastics has become a pressing task due to the severe long-term threats of plastic wastes to the ecosystem. However, the development in this area is strongly impeded by the high cost of biomass separation and the poor processability of unseparated biomass. Herein, we demonstrate, for the first time, an efficient and scalable method to generate greener plastics by directly integrating unseparated biomass waste (i.e., wood powder) with crosslinked covalent adaptable networks. Through a simple compression molding process, the wood biomass and polymer particles can be fused together to form a continuous material, which is endowed with repairability, reprocessibility, and closed-loop full recyclability. The method demonstrated in this work paves the way for largescale industrial production of environmentally friendly biomass- based plastics.

Chest wall reconstruction using a new titanium mesh: a multicenters experience.

Many new surgical techniques and materials have been introduced in the last decade for chest wall reconstruction or stabilization with the purpose of improving the incorporation, maintaining chest wall stability with reduction of infections. However, none of them are yet considered a gold standard procedure. The aim of this work is to evaluate the initial experience using a new titanium mesh for chest wall reconstruction in four Italian Thoracic Surgery Departments. A review was performed of all patients undergoing chest wall reconstruction using a new titanium mesh between January 2014 and September 2018. Surgical indications, the location and size of the chest wall defect, intraoperative variables and postoperative complications were analyzed. A total of 26 consecutive patients were included. The most common indications for surgery were primary or secondary chest wall tumors (38%) followed by lung cancer invading chest wall (31%). The most common localization of chest wall defect was anterolateral (46%). Sternal reconstruction was required in 3 patients (12%). The average size of the defect was 9.3×7.8 cm. The median number of resected ribs was 3.6. No perioperative deaths occurred. Mean hospital stay was 11.9 days. Overall morbidity was 19%. One failure of reconstruction (4%) was reported during follow up. In our early clinical experience chest wall reconstruction using titanium mesh can be performed as a safe and effective surgical procedure. This mesh has excellent biomechanical characteristics between rigid and malleable materials, it's easy to trim and fix for optimal adaptation without necessity of dedicated instruments. The early and mid-term results are satisfactory with low incidence of complications related to the titanium mesh implant.

Research on the Optimal Regime of Recrystallization in 1050 Aluminium Alloy

Abstract The development of technical applications required the use of many metals and alloys, other than steel and cast iron. Thus, non-ferous metals and alloys represent a category of materials of great technical importance, their application beeing determined by their properties. The mechanical properties of Al depend on its degree of purity as well as the plastic and thermal processing it was subjected to, being used either in metallic constructions due to its low density or for electrical conductors due to its ductility in the shape of sheets and strips, being malleable materials, or foils for packaging in the food industry. In this research, it is highlighted the influence of temperature and the time of maintenance on the mechanical properties and the microscopic structure of the recrystallized metal, namely the optimal recrystallization in 1050 aluminum alloy, a popular grade of aluminum for general sheet metal work where moderate strength is required.