Notable Deformation Research Articles

Electromagnetic Slime Sentinels: Transforming Drug Delivery, Object Extraction, and Healing Innovations

Magnetic small soft-bodied robots are perfect for targeted medication administration, micromanipulation, and minimally invasive surgery because they provide non-invasive access to confined locations. Presently available magnetically operated small soft robots are based on elastomers (silicone) and fluids, such as ferrofluid or liquid metal; however, they have certain drawbacks. Robots built on elastomers have trouble deforming, which makes it challenging for them to maneuver in extremely constrained spaces. Although they may deform more easily, fluidbased robots have unstable forms and limited environmental adaptation. The non-Newtonian fluid- based magnetically actuated slime robots shown in this work combine the notable deformation capabilities of fluid-based robots with the flexibility of elastomer-based robots. These slime robots can move on different surfaces in intricate surroundings and navigate via tiny channels as little as 1.5 mm in diameter. They can carry out various tasks, including transporting, ingesting, and gripping solid items, and also adapt to various surfaces. Magnetic slime robots, combining the properties of non-Newtonian fluids and elastomers, offer promising solutions for targeted drug delivery and minimally invasive surgeries. This review discusses the design, preparation, and applications of magnetic slime robots, highlighting their potential to revolutionize biomedical operations. It also highlights their stability among different atmospheric conditions, marking a new age of targeted drug delivery systems and predicting various innovations and concepts related to magnetic slime robots.

Enhanced mechanical properties of 3D printed concrete sculpture material with wood fibers reinforcement

This study examined the mechanical characteristics of 3D printed concrete utilized in sculpture materials, with an emphasis on the incorporation of wood fibers. A series of experiments were conducted to probe into the wood fiber-reinforced 3D printed concrete sculpture materials. Through mechanical and microscopic examinations, the role of flexible fibers in enhancing the bearing capacity of concrete 3D printed components was investigated. The results indicated that an optimal amount of wood fiber addition significantly improved the mechanical properties of the concrete sculpture materials. At the interlayer interface, wood fibers exhibited elongation, thereby mitigating the specimen damage. However, beyond a certain threshold, the mechanical properties tended to decline due to either the agglomeration or direct dislodgment of wood fibers at the interlayer interface, which resulted in an absence of notable deformation. This scenario thereby failed to impede crack propagation. Hydrophobic performance assays revealed an elevation in surface hydrophobicity of 3D printed concrete sculpture materials with the inclusion of wood fibers. Yet, an excessive amount of wood fibers caused a gradual reduction in the contact angle, implying a decrease in the hydrophobicity of the material surface.

Three-dimensional interseismic crustal deformation in the northeastern margin of the Tibetan Plateau using GNSS and InSAR

The nature of the crustal deformation of the northeastern margin of the Tibetan Plateau is vital for elucidating the expansion mechanism of the plateau. We installed 21 continuous GNSS stations and obtained a horizontal velocity field with high spatial resolution. We also acquired a line-of-sight(LOS)velocity field with Sentinel-1 images covering the study area from 2014 to 2022. A multi-scale spherical wavelet method was employed to unify the reference frames of GNSS and InSAR data. After unifying the reference frame, the two data types achieve high consistency. Combining GNSS and InSAR velocities yielded the three-dimensional interseismic velocity field in the northeastern margin of the Tibetan Plateau. Furthermore, we analyzed the crustal deformation characteristics based on the three-dimensional deformation field. The crustal deformation exhibits a pronounced northeastward shift relative to the Ordos block, whereas the interior of the Ordos block remains remarkably stationary, behaving as a rigid unit. The Liupanshan fault is primarily characterized by uplift, devoid of any notable horizontal deformation across the fault. The left-lateral strike-slip mainly characterizes the Haiyuan fault.. The maximum east–west deformation velocity on the southern side of the fault is approximately 3.9 mm/yr, decreasing to about 1.0 mm/yr at the eastern end of the fault. The western segment of the West Qinling fault exhibits a minor east–west motion. Our result provides essential data for further study of the crustal deformation patterns.

Alar base symmetry in orthognathic surgery: Patients with unilateral cleft.

Patients with unilateral cleft lip and palate (UCLP) could present with a notable nasal deformity with alar base retrusion, which should be considered when planning orthognathic surgery (OGS). This retrospective study included 84 patients with Class III malocclusion. Cone beam computed tomographic data were used for the investigation. 42 patients had complete UCLP, and the other 42 did not have a cleft. All the patients underwent preoperative virtual surgical planning. Preoperative and postoperative images were used to measure anteroposterior changes in the bone and soft tissue at the alar bases. In the UCLP group, varying degrees of alar base discrepancies were observed before surgery. In the piriform region of the cleft side, the bone was retruded in 32 cases, but the soft tissue was thicker in 38 cases, and the mean skin surface was anterior in 28 cases. After surgery, the bone discrepancy was not significantly changed (p = 0.288), however, the skin surface symmetry was improved (p = 0.013). Relating to the bone advancement, the ratio of soft tissue change was smaller on the cleft side than the noncleft side (0.56 ± 0.30 vs. 0.77 ± 0.33, p < 0.001). In the control group, a consistent ratio change was observed on both sides (0.76 ± 0.19 vs. 0.79 ± 0.27, p = 0.544). This study revealed improved alar base symmetry in patients with UCLP after OGS. The soft tissue change ratios were different across the cleft, which should be considered during treatment planning.

Atomistic understanding of ductile-to-brittle transition in single crystal Si and GaAs under nanoscratch

Ensuring ductile removal in a grinding process is crucial for achieving the desired finish on a hard and brittle single crystal. This study provides new insights into the material removal processes in Si and GaAs single crystals, exploring their deformation behaviour using Berkovich and Conical tips to replicate contact from a fixed abrasive grit. Experimental observations are compared with Molecular Dynamic (MD) simulations to uncover the atomistic deformation mechanisms during the ductile-to-brittle transition (DBT). Notable plastic deformation and minimal cracking were consistently observed in Si, irrespective of the tips used. MD simulations supported this observation, revealing pronounced chip formation indicative of ductile material removal. The resistance to cracking in Si was attributed to amorphization induced by localized high contact stresses. In contrast, GaAs showed a propensity for cracking, with MD simulations revealing dislocation and slip band formation, and cracks emerging in the areas of substantial plastic deformation. These findings address phenomena not previously discernible in experimental studies due to the challenge of real-time observation. Moreover, the tip geometry was shown to significantly influence stress distribution, impacting deformation and crack formation in GaAs. This study also reveals limitations in predicting the critical depth for DBT in both Si and GaAs throught the amended Bifano, Dow, and Scattergood (aBDS) models and MD simulation, offering nuanced insights into these challenges that have not been extensively explored. It was found that the experimental results exceeded predictions by an order of magnitude. These discrepancies underscore the aBDS model's disregard for essential material properties and tip geometry, while the disparities between MD simulation and experiment are primarily attributed to the inherent limitations in the simulated length scales and challenges in detecting initial subsurface cracks.

Bandgap Tuning Based on Multi-Stable Metamaterial with Multi-Step Deformation

Mechanical metamaterials are highly versatile structures capable of achieving unconventional mechanical properties. Of particular interest are mechanical metamaterials with the ability to tune bandgaps, offering potential applications in vibration control tailored to specific requirements. In this study, a new type of metamaterial is introduced to exhibit a distinctive two-step deformation mode under compressive displacement. Through a combination of numerical simulation and experimental verification, the band structure and vibration characteristics of the novel metamaterial in different stable states are thoroughly examined under compressive displacement. The results demonstrate that, in comparison to the initial structure, the novel mechanical metamaterial effectively addresses the issue of a significant reduction in plateau stress relative to buckling stress following buckling in the second deformation stage. The novel structure showcases notable controllable deformation capabilities, yielding distinct band structures in various stable states, and facilitating bandgap tuning. Furthermore, the study explores the influence of geometrical parameters and stable state transitions on bandgap evolution, supported by frequency response analyses and experimental validation. This research offers a fresh perspective on the utilization of Multistable Multi-Step Deformation Metamaterial (MMDM) for energy absorption and vibration damping applications.

Computational design of custom-fit PAP masks

Positive airway pressure (PAP) therapy refers to sleep disordered breathing treatment that uses a stream of compressed air to support the airway during sleep. Even though the use of PAP therapy has been shown to be effective in improving the symptoms and quality of life, many patients are intolerant of the treatment due to poor mask fit. In this paper, our goal is to develop a computational approach for designing custom-fit PAP masks such that they can achieve better mask fit performance in terms of mask leakage and comfort. Our key observation is that a custom-fit PAP mask should fit a patient’s face in its deformed state instead of in its rest state since the PAP mask cushion undergoes notable deformation before reaching an equilibrium state during PAP therapy. To this end, we compute the equilibrium state of a mask cushion using the finite element method, and quantitatively measure the leakage and comfort of the mask cushion in this state. We further optimize the mask cushion geometry to minimize the two measures while ensuring that the cushion can be easily fabricated with molding. We demonstrate the effectiveness of our computational approach on a variety of face models and different types of PAP masks. Experimental results on real subjects show that our designed custom-fit PAP masks are able to achieve better mask fit performance than a generic PAP mask and custom-fit PAP masks designed by a state-of-the-art approach.

Fire performance of steel reinforced concrete column to reinforced concrete beam planar frames: Experiment

This paper investigates the fire performance of large-scale steel reinforced concrete (SRC) column to reinforced concrete (RC) beam planar frames by a series of fire resistance tests. The testing parameters included beam load ratio, column steel ratio and column dimension. The test results indicated that, in fire condition, the SRC column to RC beam frame exhibited two primary failure modes: beam shear failure and column compression failure. In the case of beam shear failure, the fire resistance of frame specimens increased as the beam load decreased. In the scenario of column compression failure, out-of-plane failure occurred due to the weak axis of the SRC column being located outside the frame plane. Concurrently, the RC beam displayed significant shear deformation at the ends and notable bending deformation in the middle. The test results indicated that the column cross-sectional size notably influenced the fire resistance of SRC column to RC beam frame, however, the influence of column steel ratio was minimal.

Experimental investigation on the deformation behavior of an isotropic 304L austenitic steel manufactured by laser powder bed fusion with hot isostatic pressing

Post-heat treatment, such as hot isostatic pressing (HIP), is increasingly employed in laser powder bed fused (L-PBF) metallic materials to release residual stress, alleviate microstructural anisotropy, and tailor mechanical properties. Here, we systematically investigate the initial and deformed microstructures of as-received and HIPed L-PBF 304L austenitic steel using various microstructural characterizations. The results indicate that the HIP procedure can decrease the porosity and generate the columnar-to-equiaxed transition (CET), resulting in an isotropic microstructural morphology better suitable for practice applications. Additionally, the HIP samples have exceptional ductility when compared to as-received samples, which is associated with the sustained strain hardening rate arising from the notable deformation twinning behavior. The majority of deformation twins are preferentially emitted from the straight annealing twin boundaries and then grow within the 〈111〉 − oriented annealing twins. The principle twinning mechanism involved is the twinning partial emission from the annealing twin boundaries or high-angle grain boundaries (HAGBs). Moreover, the inclusions distributed near/on the annealing twin boundaries can emit partials with multiple Burgers vectors during straining, resulting in the extra random activation of partials (RAP) twinning mechanism that sustains the deformation process. These findings give helpful suggestions for HIP process designs of L-PBF austenitic steels, as well as a solid foundation for future theoretical modeling research.

Experimental investigation of the behavior of UHPCFST under repeated axial tension

A ultra-high performance concrete filled steel tube (UHPCFST) is a composite structural component that extends the performance of both steel and concrete. It is a promising component to be used in a diagrid structure to further reduce self-weight. Compared with the research on compressive performance of UHPCFST, there is a lack of knowledge on the mechanical behavior of UHPCFST under axial tension. This paper fills this knowledge gap by carrying out experiments on UHPCFST subjected to monotonic and repeated tension. The test parameters are steel tube thickness and volume fraction of ultra-high performance concrete (UHPC). The failure modes, load-strain curves, tensile strength and tensile stiffness are studied in detail. Stiffness degradation is also studied. The test results show that: (1) under axial tension load, a UHPCFST typically experiences fracture failure of the outer steel tube, followed by section fracture of the UHPC, and notable deformation before a final ductile failure; (2) tensile strength increases with the increase of the thickness of the steel tube, while it is less obvious in a UHPCFST with a higher steel ratio; (3) the force-strain curve of a UHPCFST under monotonical axial tension is close to that of the UHPCFST under repeated axial tension, suggesting that the accumulated damage during unloading and reloading is limited. An exponential decay formula is proposed to predict stiffness degradation observed in the repeated axial tensile tests. It is found that the design codes from Europe, USA, and China underestimate tensile strength and stiffness of UHPCFST. Finally, a three-phase empirical model is proposed for the load-strain curve of UHPCFST under tension.

Research on bird strike resistance performance of hollow plates with warren structure

This study initially conducted bird strike tests and numerical simulations on hollow plates with the Warren structure. The plates manifested notable plastic deformation devoid of fracture. The simulated deformations and strain data of the plates closely corresponded with the outcomes of bird strike impact tests, thereby validating the employed bird strike simulation methodology in this study. Subsequently, while maintaining the outer dimensions of the hollow plate constant, an investigation into the structural parameters of the hollow plate was conducted. Correlations between the thickness of the outer panel, thickness of the Warren, angle of the Warren, and the anti-bird-strike performance of the hollow plate structure were established. The research findings offer valuable insights for informing the design of bird strike resistance in engine blades and hollow plates.

Reverse Shoulder Arthroplasty to Treat Proximal Humerus Fracture Sequelae: A Review.

While several proximal humerus fractures treated nonsurgically reach satisfactory outcomes, some become symptomatic malunions or nonunions with pain and dysfunction. When joint-preserving options such as malunion or nonunion repair are not optimal because of poor remaining bone stock or glenohumeral arthritis, shoulder arthroplasty is a good option. Because of the semiconstrained design of reverse shoulder arthroplasty, it is effective at improving function when there is notable bony deformity or a torn rotator cuff. Clinical studies have demonstrated reliable outcomes, and a classification system exists that is helpful for predicting prognosis and complications. By understanding the associated pearls and pitfalls and with careful management of the tuberosities, reverse shoulder arthroplasty is a powerful tool for managing proximal humerus fracture sequelae.

Chara virgata (Charophyceae, Characeae) – new species record for the south of the Far East (the Kurils), unusual stem cortex deformation

Chara virgata Kütz. was found in a sphagnum bog on Urup Island of the Kurils. This is a first species record of charophytes for the Sakhalin Region and new species record for the south of the Far East. The plants have notable deformation of stem cortex at old parts rarely noted for Chara L. and unknown for this species.

Seismic behavior of Q620 high-strength steel welded Box-section columns: Experimental tests, analysis, and model

This study experimentally and numerically investigates the seismic behavior of high-strength steel (HSS) welded Box-section columns. The HSS structures have made rapid development in various types of building structures. However, the high yield-to-tensile ratio of HSS limits its application in seismic design. To address this gap, a new type of HSS called Q620 has been developed by Hebei Iron and Steel Co., Ltd. (HISCO). A total of three specimens were designed by this seismic-resistant Q620 HSS material and tested under cyclic load. The main failure modes included local buckling of the bottom section of the column, and obvious flexural deformation led to fracture of the specimen. Additionally, the nonlinear kinematic hardening model was utilized to accurately establish the finite element (FE) model for the HSS welded Box-section columns. Based on the validated FE model, an extensive parametric analysis (e.g., width-to-thickness ratio, axial compression ratio, and slenderness ratio) was conducted to evaluate the seismic behavior of the Q620 HSS welded Box-section columns. The results indicated that the Box-section columns exhibited favorable hysteretic behavior and notable plastic deformation capacity. A higher width-to-thickness ratio resulted in a faster decline in stiffness and a more pronounced advancement of damage. The ductility and energy dissipation capacity of Box-section columns were generally decreased with increasing axial compression ratio or slenderness ratio. A newly simplified hysteretic model was proposed, which was in good agreement with the experimental results.

UV-activated semiconductor gas sensor response measurement for formaldehyde detection

The gas sensing characteristics of ultraviolet light-emitting diodes (UV-LEDs)-activated semiconductor sensors were investigated to detect formaldehyde (HCHO) as a model volatile organic compound (VOC). As the major drawback of formaldehyde gas sensors is the low durability of the sensing material, efforts were made to establish a suitable metal oxide semiconductor and to enhance its stability throughout the sensing process. In2O3 nanoparticles (NPs) as the sensing material showed restructuring caused by exposure to different concentrations of formaldehyde in the presence of UV radiation when its morphology and structure were analyzed. UV radiation in the presence of formaldehyde was found to play a critical role in nanoparticles agglomeration, as well as its response inconsistency and instability.The novel method of measuring UV radiation elimination in the initial stages of the response curve was deemed effective for sensing layer preservation in this study. The scanning electron microscopy (SEM) results showed that this approach prevented any notable deformation in the nanoparticles’ shape and size and resulted in reproducible responses to various formaldehyde concentrations (10–50 ppm) in the steady-state and transient (5 min exposure) phases of the response curve. Hence, a short-time UV exposure has the potential to be applied in practical gas sensing applications in which the sensor can be automatically turned off a few minutes after any target gas detection. The gas sensor response slope in the transient phase of the response curve was found to be a very good indicator of target gas concentration and to obtain fast and consistent results while preserving the sensing material from restructuring. The findings of this study can be incorporated into the development of UV-LED-activated gas sensors where stable and fast response measurements of VOCs are required.

Building earthquake resilience with clay shale: pioneering sustainable concrete solutions with eco-friendly materials

This study examines the potential of using locally sourced clay shale as an eco-friendly addition to concrete formulations, aimed at boosting both structural strength and seismic resilience in earthquake-prone regions. Optimized using the Dreux-Gorisse method, the clay shale-based concrete achieved a compressive strength of 12 MPa after seven days and 16 MPa after 28 days, meeting B25 concrete standards. Seismic testing with cyclic loading at a frequency of 1 Hz demonstrated notable ductility and deformation resistance, with a 9% increase in compressive strength compared to conventional concrete mixes. The use of clay shale also helped reduce the concrete's carbon footprint by approximately 12%, thanks to a reduced need for transported materials, making it a sustainable and cost-effective choice. These findings suggest that clay shale concrete offers a robust, resilient option for construction in seismic regions, balancing sustainability with structural reliability. Future studies should explore the material’s long-term durability and in-field performance to confirm its potential further. This study highlights the value of integrating geotechnical and seismic resilience into sustainable infrastructure, aligning with global goals to lower environmental impact and improve community safety.

Construction quality control of concrete structures in architectural engineering—A case in Shanghai, China

&lt;p&gt;Architectural concrete provides diverse patterns, colors, and forms, offering extensive structural and aesthetic possibilities. In China, advanced techniques such as prefabricated and precast concrete structures are increasingly utilized, delivering benefits like faster construction, reduced resource use, and improved quality control. Recent studies in China have highlighted the environmental benefits and practical considerations of incorporating recycled materials and moderate-heat Portland cement into concrete, which offer promising sustainability advantages. This study, through a case analysis in China, explored the usability, durability, manufacturing costs, and economic implications of architectural concrete. It emphasizes the critical role of architectural concrete in modern structural engineering, financial planning, and design, aiming to reduce variability in strength and uniformity between concrete batches, ensure consistent material quality, and lower maintenance costs while accelerating production. Focusing on quality control in concrete construction in Heqing, Pudong, Shanghai, this research identified unique challenges and provided insights. In Shanghai's architectural context, continuous monitoring of concrete quality is essential for structural stability and durability. This study also addressed the resilience of concrete structures in saltwater and freeze-thaw conditions, underscoring the need to consider environmental factors in quality assurance. Laboratory experiments demonstrated that composite members and deep beams of steel and concrete exhibit notable deformation and shear resistance, highlighting the importance of meticulous material selection and structural design for effective quality control.&lt;/p&gt;

Reevaluation of Hemoparasites in the Black Spiny-Tailed Iguana (Ctenosaura similis) with the First Pathological and Molecular Characterizations of Lankesterella desseri n. sp. and Redescription of Hepatozoon gamezi.

Hemoprotozoa are microorganisms that parasitize the blood and possess intricate life cycles. Despite the complexity of their nature, little is known about the biology of hemoprotozoa in reptilian hosts. In this study, we conducted disease surveillance on blood samples collected from six black spiny-tailed iguanas (Ctenosaura similis) exhibiting clinical signs. We found two different types of hemoparasites in the blood films and further confirmed they belong to the genera Lakesterella and Hepatozoon through molecular methods. In the tissue section from a dead iguana infected only with Lakesterella sp., parasites were also found in melanomacrophages of the liver and kidney. Since Lakesterella sp. infection has not been reported in C. similis, we propose this hemococcidian as a new species, Lankesterella desseri n. sp. The Hepatozoon parasites discovered in this study were classified as Hepatozoon gamezi based on their morphological characteristics, particularly the notable deformation of all infected erythrocytes, and this classification was further corroborated through molecular biological and phylogenetic analyses. This is the first hemoprotozoa investigation in C. similis with pathological and molecular characterization of these pathogens. We suggest that more studies are needed to understand the epidemiology, transmission, and impact of these parasites on their hosts and ecosystems.

The Mechanical Properties and Degradation Behavior of 3D-Printed Cellulose Nanofiber/Polylactic Acid Composites.

Polylactic acid (PLA) has been widely used in many fields because of its good biodegradability, biocompatibility, and renewability. This work studied the degradation behavior and mechanical properties of cellulose nanofiber (CNF)/PLA composites. In vitro degradation experiments of 3D-printed samples were conducted at elevated temperatures, and the degradation characteristics were evaluated by mechanical tests, gel permeation chromatography (GPC), differential scanning calorimetric (DSC), and scanning electron microscope (SEM). The results indicated that the addition of CNF (0.5 wt%) accelerated the degradation rate of PLA. The decreases in number average molecular weight (Mn) and weight average molecular weight (Mw) of composites were 7.96% and 4.91% higher than that of neat PLA, respectively. Furthermore, the tensile modulus of composites was 18.4% higher than that of neat PLA, while the strength was 7.4% lower due to poor interfacial bonding between CNF and PLA. A mapping relationship between accelerated and normal degradation showed that the degradation experienced during 60 days at 37 °C was equivalent to that undergone during 14 days at 50 °C; this was achieved by examining the alteration in Mn. Moreover, the degradation process caused a notable deformation in the samples due to residual stress generated during the 3D printing process. This study provided valuable insights for investigating the in vitro degradation behavior of 3D-printed products.

Gaussian and circular oscillating laser directed energy deposition of WC/NiCu composites

In the realm of laser directed energy deposition (L-DED), the standard procedure typically using a Gaussian laser as the primary energy source. However, this well-established technique also has limitations as it generates considerable temperature gradients and residual stresses throughout the manufacturing process, resulting in notable deformation and cracking. To overcome these limitations, this study advocates for the replacement of the Gaussian laser with a circular oscillating laser. NiCu alloys and 16 wt% WC/NiCu composites were manufactured using the Gaussian laser and the circular oscillating laser deposition equipment. The results of this study reveal that the circular oscillating laser methodology exerts a pronounced agitation effect on the melt pool, thus hindering the formation of columnar dendrites and promoting the emergence of more nucleation sites for the growth of equiaxed dendrites. This method effectively refines the grains by reducing the temperature gradient of the melt pool and increasing the cooling rate. The average grain size of NiCu alloy manufactured using the circular oscillating laser is reduced by 19.5% compared to that manufactured using the Gaussian laser. The high temperature generated by laser and melt pool caused partial decomposition of WC into W and C, leading to the formation of W2C hard phases between the dendrites. Additionally, the unmelted WC particles were uniformly dispersed throughout the composites, which hindered the growth of columnar dendrites and refined the grains. Compared to the composites manufactured using the Gaussian laser, the composites manufactured using the circular oscillating laser exhibit an average microhardness increase of 15% and 11.1%, and a 76.5% and 22.2% decrease in wear rate, respectively. Composites containing 16 wt% WC manufactured using the Gaussian laser exhibit the best corrosion resistance.