Mechanical Support Structure Research Articles

Analysis of the Influence of Rock Mechanics Variables on the Stability of Tunnel Surrounding Rock Based on Engineering Mathematics Applications

Tunnels are essential infrastructure elements, and it is critical to maintain their stability for both operation and safety. Using engineering techniques, this study examines the correlation between rock mass motorized characteristics and tunnel surrounding rock stability. This study utilizes the multi-sensor monitoring data of the surrounding rock mechanical characteristics and tunnel support structure collected during tunnel boring machine construction as its research object. The integrated cuckoo search optimized Upgraded dynamic convolutional neural network (ICSO-UDCNN) has been utilized for predicting the tunnel parameters. In general, the surrounding rock’s hardness correlates with its level, which in turn determines how quickly tunnels are being excavated. There is a stronger correlation of 98\% between the field penetration index (FPI) variables of the rock’s characteristic slope along the conditions surrounding the tunnel. The most significant factor influencing its deformation is the surrounding rock’s mechanical characteristics. For engineers and other decision-makers engaged in tunnel design, building, and maintenance, the study’s findings add a greater understanding of the variables affecting tunnel stability. This research provides an establishment for enhancing security protocols, lowering hazards related to tunneling operation, and optimizing tunnel engineering techniques by quantitatively evaluating the influence of rock mass mechanical factors on solidity.

Free-standing millimeter-range 3D waveguides for on-chip optical interconnects

Next-generation energy-efficient photonic integrated systems, such as neuromorphic computational chips require efficient heterogeneous integration of ultracompact light sources and photodetectors through highly dense waveguide circuits. However, interconnecting these devices in emitter-receiver communication circuits remains a challenge and an obstacle towards upscaling heterogeneous photonic chips. Here we report on versatile air-cladded free-standing 3D polymer waveguides (OrmoCore, n≈1.5) spanning up to 900 µm in length without intermediate mechanical support structures, microprinted via two-photon polymerization. The presented waveguides are suitable for on-chip out-of-plane light coupling as well as non-connected 3D crossings, needed for high density optical circuits. The waveguides show optical transmission losses of 1.93 dB mm−1 at λ = 635 nm, and of 3.71 dB mm−1 at λ = 830 nm in the wavelength range of GaAs-based microLEDs spectral emission. On-chip imaging for high-precision alignment and TPP microfabrication are performed seamlessly by utilizing the same laser source for both steps, allowing accurate 3D printing on microstructured substrates. As proof of concept, we interconnect two GaAs-based microLEDs via an on-chip microprinted 3D waveguide. Such combined systems can serve as building blocks of future complex integrated heterogeneous photonic networks.

High-Density, Conformable Conducting Polymer-Based Implantable Neural Probes for the Developing Brain.

Neurologic and neuropsychiatric disorders substantially impact the pediatric population, but there is a lack of dedicated devices for monitoring the developing brain in animal models, leading to gaps in mechanistic understanding of how brain functions emerge and their disruption in disease states. Due to the small size, fragility, and high water content of immature neural tissue, as well as the absence of a hardened skull to mechanically support rigid devices, conventional neural interface devices are poorly suited to acquire brain signals without inducing damage. Here, the authors design conformable, implantable, conducting polymer-based probes (NeuroShanks) for precise targeting in the developing mouse brain without the need for skull-attached, rigid mechanical support structures. These probes enable the acquisition of high spatiotemporal resolution neurophysiologic activity from superficial and deep brain regions across unanesthetized behavioral states without causing tissue disruption or device failure. Once implanted, probes are mechanically stable and permit precise, stable signal monitoring at the level of the local field potential and individual action potentials. These results support the translational potential of such devices for clinically indicated neurophysiologic recording in pediatric patients. Additionally, the role of organic bioelectronics as an enabling technology to address questions in developmental neuroscience is revealed.

3D Printed Proto Type Model of Pelton Turbine Runner

Nowadays, different methods are used in the renewable energy sector for the fabrication of prime movers. A broad classification of the latest additive manufacturing technologies is discussed with ten different parameters like material used, speed, part size, accuracy, application, surface finish, complexity, costing, strength and weakness. Additive manufacturing or 3D printing is also referred to as digital manufacturing technology. 3D printing technology creates physical objects from a geometrical representation by successive addition of materials. Polylactic acid material will be cost-effective to develop the laboratory scale prototype Pelton turbine model. The fused deposition method gives durable products with plastic filament material. FDM provides an optimum condition for the manufacturing of curved surfaces. A step by step process is emphasis for the digital printing of 3D Pelton buckets, runner and shaft. Difficulties associated with the orientation of the Pelton bucket is overcome by using mechanical support structures.

AGATA: mechanics and infrastructures

The successful operation of AGATA requires a complex mechanical support structure for the safe and reliable operation of the detectors. Three mechanical structures were designed for the scientific campaigns at LNL, GSI and GANIL, each accommodating an increasing number of detectors. The present phase of the project, to increase the number of detectors from 60 to 180 (the 4pi spectrometer), required a new concept in mechanical support. The detectors also require a suite of associated instrumentation, infrastructures and good system design for their optimum performance. This includes the automatic liquid nitrogen filling system, high and low voltage power supplies, and a series of signal cables and distribution systems. A well-designed electromagnetic compatibility across all the sub-systems is essential. An additional requirement is an easily accessible database that records the status of the wide range of components utilised on the project. This article describes all aspects of the mechanics and infrastructures.

Design Optimization of Mechanical Support Structures in Tunable Vertical Cavity Surface Emitting Lasers

Design Optimization of Mechanical Support Structures in Tunable Vertical Cavity Surface Emitting Lasers

Xylem anatomical traits determine the variation in wood density and water storage of plants in tropical semiarid climate

Wood density (WD) is a functional trait that integrates hydraulic safety and efficiency, water and carbohydrate storage, and biomechanical properties of plants. The global economic spectrum of wood shows that average WD tends to be higher in dry regions than in humid regions. In this study, we investigated the factors determining WD variation, the maximum water content in wood (WCmax), and their possibly consequences to hydraulic functioning of plants under tropical semiarid climate. Fourteen xylem anatomical traits related to mechanical support, water storage, and hydraulic efficiency and safety were measured in 39 woody species commonly found in a seasonally dry tropical forest in the Brazilian semiarid region. We tested the phylogenetic signal of all traits. The range of WD was 0.24–0.85 g cm−3 (average WD = 0.62 g cm−3). Fractions of vessel wall, fiber wall, fiber lumen, and fiber type highly influenced WD. Septate and gelatinous fibers decreased WD, whereas libriform fibers contributed to the increase in WD. Axial and radial parenchyma, fiber lumen fractions, and septate fibers presence determined WCmax variation. Xylem anatomical traits showed a weak phylogenetic signal. Wood density had a phylogenetic antisignal, indicating a functional convergence independent of phylogenetic proximity, despite species varying in their anatomical patterns. We conclude that the increase in the average WD in the analyzed species was associated with the investment in vessel wall, fiber wall fraction, and libriform fibers (mechanical support structures), which possibly increase hydraulic safety. Thus, we suggest that fiber types are important determinants of WD and WCmax and should receive more attention.

Study of the performances of the DAMPE silicon-tungsten tracker after five years of mission

DAMPE (DArk Matter Particle Explorer) is a satellite-based experiment launched in December 2015 and smoothly taking data after five years of mission. The Silicon-Tungsten Tracker (STK) is characterized by 6 double layers of silicon micro-strip detectors, for a total detection area of 7 m2, and three 1 mm thick tungsten plates, placed in the mechanical support structure, aimed to the photon conversion in e± pairs. The STK has a double role: precise reconstruction of the track of charged particles with a spatial resolution around 40 μm for most incident angles of the incoming particles, identification of the charge of the incoming cosmic rays. The STK performances are excellent after five years of continuous operation in space: in this contribution the STK in-orbit calibration and performances during the whole DAMPE mission will be presented.

A 3D printed mimetic composite for the treatment of growth plate injuries in a rabbit model

Growth plate injuries affecting the pediatric population may cause unwanted bony repair tissue that leads to abnormal bone elongation. Clinical treatment involves bony bar resection and implantation of an interpositional material, but success is limited and the bony bar often reforms. No treatment attempts to regenerate the growth plate cartilage. Herein we develop a 3D printed growth plate mimetic composite as a potential regenerative medicine approach with the goal of preventing limb length discrepancies and inducing cartilage regeneration. A poly(ethylene glycol)-based resin was used with digital light processing to 3D print a mechanical support structure infilled with a soft cartilage-mimetic hydrogel containing chondrogenic cues. Our biomimetic composite has similar mechanical properties to native rabbit growth plate and induced chondrogenic differentiation of rabbit mesenchymal stromal cells in vitro. We evaluated its efficacy as a regenerative interpositional material applied after bony bar resection in a rabbit model of growth plate injury. Radiographic imaging was used to monitor limb length and tibial plateau angle, microcomputed tomography assessed bone morphology, and histology characterized the repair tissue that formed. Our 3D printed growth plate mimetic composite resulted in improved tibial lengthening compared to an untreated control, cartilage-mimetic hydrogel only condition, and a fat graft. However, in vivo the 3D printed growth plate mimetic composite did not show cartilage regeneration within the construct histologically. Nevertheless, this study demonstrates the feasibility of a 3D printed biomimetic composite to improve limb lengthening, a key functional outcome, supporting its further investigation as a treatment for growth plate injuries.

Design of CCT6: A Large Aperture, Nb$_3$Sn Dipole Magnet for HTS Insert Testing

We present the design of a four-layer, Canted Cosine Theta (CCT) Nb <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_3$</tex-math></inline-formula> Sn dipole magnet as part of the general R&D program for high field superconducting magnets supported by the US Magnet Development Program (US-MDP). Future testing with High-Temperature Superconducting (HTS) inserts in a hybrid configuration motivates the design’s large clear aperture of 120 mm and target operating dipole field of 12 T at 4.2 K. First, we present a graded magnetic design utilizing existing Nb <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_3$</tex-math></inline-formula> Sn cables which results in 30% operating current margin at the target field. We then share results from a 2D mechanical analysis which makes use of an idealized external structure to provide initial guidance for design studies. This mechanical analysis is extended to demonstrate compatibility of the CCT6 design with a mechanical support structure, based on key and bladder technology, currently considered for use within multiple US-MDP high-field magnet programs.

Combining one and two photon polymerization for accelerated high performance (3 + 1)D photonic integration

Abstract Dense and efficient circuits with component sizes approaching the physical limit is the hallmark of high performance integration. Ultimately, these features and their pursuit enabled the multi-decade lasting exponential increase of components on integrated electronic chips according to Moore’s law, which culminated with the high performance electronics we know today. However, current fabrication technology is mostly constrained to 2D lithography, and thermal energy dissipation induced by switching electronic signal lines presents a fundamental challenge for truly 3D electronic integration. Photonics reduces this problem, and 3D photonic integration is therefore a highly sought after technology that strongly gains in relevance due to the need for scalable application-specific integrated circuits for neural networks. Direct laser writing of a photoresin is a promising high-resolution and complementary metal-oxide-semiconductor (CMOS) compatible tool for 3D photonic integration. Here, we combine one and two-photon polymerization (TPP) for waveguide integration for the first time, dramatically accelerating the fabrication process and increasing optical confinement. 3D additive printing is based on femtosecond TPP, while blanket irradiation with a UV lamp induces one-photon polymerization (OPP) throughout the entire 3D chip. We locally and dynamically adjust writing conditions to implement (3 + 1)D flash-TPP: waveguide cores are printed with a small distance between neighboring writing voxels to ensure smooth interfaces, mechanical support structures are printed at maximal distance between the voxels to speed up the process. Finally, the entire chip’s passive volume not part of waveguide cores or mechanical support is polymerized in a single instance by UV blanket irradiation. This decouples fabrication time from the passive volume’s size. We succeed in printing vertical single-mode waveguides of 6 mm length that reach numerical apertures up to NA = 0.16. Noteworthy, we achieve exceptionally low −0.26 dB injection losses and very low propagation losses of −1.36 dB/mm at λ 0 = 660 nm, which is within one order of magnitude of standard integrated silicon photonics. Finally, the optical performance of our waveguides does not deteriorate for at least ∼3000 h after printing, and remains stable during ∼600 h of continuous operation with 0.25 mW injected light.

Bidirectional regulation of structural damage on autophagy in the C. elegans epidermis

ABSTRACT A variety of disturbances such as starvation, organelle damage, heat stress, hypoxia and pathogen infection can influence the autophagic process. However, how the macroautophagy/autophagy machinery is regulated intrinsically by structural damage of the cell remains largely unknown. In this work, we utilized the C. elegans epidermis as the model to address this question. Our results showed that structural damage by mechanical wounding exerted proximal inhibitory effect and distant promotional effect on autophagy within the same epidermal cell. By disrupting individual mechanical supporting structures, we found that only damage of the basal extracellular matrix or the underlying muscle cells activated a distinct autophagic response in the epidermis. On the contrary, structural disruption of the epidermal cells at the apical side inhibited autophagy activation caused by different stress factors. Mechanistic studies showed that the basal promotional effect of structural damage on epidermal autophagy was mediated by a mechanotransduction pathway going through the basal hemidesmosome receptor and LET-363/MTOR, while the apical inhibitory effect was mostly carried out by activation of calcium signaling. Elevated autophagy in the epidermis played a detrimental rather than a beneficial role on cell survival against structural damage. The results obtained from these studies will not only help us better understand the pathogenesis of structural damage- and autophagy-related diseases, but also provide insight into more generic rules of autophagy regulation by the structural and mechanical properties of cells across species. Abbreviations : ATG: autophagy related; BLI-1: BLIstered cuticle 1; CeHDs: C. elegans hemidesmosomes; COL-19: COLlagen 19; DPY-7: DumPY 7; ECM: extracellular matrix; EPG-5: ectopic PGL granules 5; GFP: green fluorescent protein; GIT-1: GIT1 (mammalian G protein-coupled receptor kinase InTeractor 1) homolog; GTL-2: Gon-Two Like 2 (TRP subfamily); HIS-58, HIStone 58; IFB-1: Intermediate Filament, B 1; LET: LEThal; LGG-1: LC3, GABARAP and GATE-16 family 1; MTOR: mechanistic target of rapamycin; MTORC1: MTOR complex 1; MUP-4: MUscle Positioning 4; NLP-29: Neuropeptide-Like Protein 29; PAT: Paralyzed Arrest at Two-fold; PIX-1: PIX (PAK (p21-activated kinase) Interacting eXchange factor) homolog 1; RFP: red fluorescent protein; RNAi: RNA interference; SQST-1: SeQueSTosome related 1; UNC: UNCoordinated; UV: ultraviolet; VAB-10: variable ABnormal morphology 10; WT: wild type.

A Study on the Effectiveness in Reducing Seismic Demand due to Targeted Element Ductility of Mechanical System Support Structure

An analytical evaluation of the effect of the plastic deformation of the support structure of mechanical components on reducing the seismic demand of the equipment is attempted using a simple two-masses model. The element ductility factor of the support structure is varied stepwise, and changes in the resonance curves of the sinusoidal acceleration wave input and the elasto-plastic seismic response curves of the strong-motion recorded waveform input are examined. Although a relatively small target element ductility factor is set in this report, which aims at a simplified seismic design method in the plastic region, it was observed that the seismic demand decreases significantly from the elastic state by slight plasticization of the support structure element, and the response spectrum becomes flat even in the resonance with the input motion and in the rigid region.

Investigation on Electrical, Thermal, and Mechanical Properties of Silicone Rubber ATH Nanocomposites

In the present study, investigations have been carried out by choosing the nano-sized ATH (30 – 50 nm) particles as filler content in silicone rubber to acquire a deep insight to understand the use of nano ATH fillers in silicone rubber on its performance, to use it as insulation structure as an outdoor insulator. Variation in the surface condition of silicone rubber nanocomposites due to corona aging and the recovery characteristics analysis carried out through contact angle measurement. Nano ATH added in silicone rubber, up to 3 wt% of filler, shows increased dielectric constant with less loss factor. Water droplet-initiated discharges on silicone rubber nano ATH composites under DC voltage measured using UHF technique and the damage caused zone analyzed through AFM studies and by surface potential measurement, which indicates higher surface roughness and increased charge trap depth. It is observed that negative DC voltage has higher CIV followed by positive DC and AC voltage. Laser Induced breakdown studies (LIBS) show a direct correlation between plasma temperature and material surface hardness. Also, on laser shining on the surface of the specimen, its temperature was measured on the backside of the specimen through thermal imaging confirming increased diffusivity of temperature. Laser flash analysis shows a direct correlation between filler content in base polymer and thermal conductivity and diffusivity. Higher storage modulus and activation energies measured from the dynamic mechanical analysis indicate the significance of prepared composites as an excellent mechanical support structure for the power system network.

The spider cuticle: a remarkable material toolbox for functional diversity.

Engineered systems are typically based on a large variety of materials differing in composition and processing to provide the desired functionality. Nature, however, has evolved materials that are used for a wide range of functional challenges with minimal compositional changes. The exoskeletal cuticle of spiders, as well as of other arthropods such as insects and crustaceans, is based on a combination of chitin, protein, water and small amounts of organic cross-linkers or minerals. Spiders use it to obtain mechanical support structures and lever systems for locomotion, protection from adverse environmental influences, tools for piercing, cutting and interlocking, auxiliary structures for the transmission and filtering of sensory information, structural colours, transparent lenses for light manipulation and more. This paper illustrates the ‘design space’ of a single type of composite with varying internal architecture and its remarkable capability to serve a diversity of functions.This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 1)’.

Multi-photon 3D imaging with an electrothermal actuator with low thermal and inertial mass

Design and testing of a low-mass electrothermal vertical scanning mirror for fast axial scanning during multi-photon microscopy is presented. The mirror makes use of a novel honeycomb mechanical support structure to substantially reduce both thermal and inertial mass relative to mirror size. At the same time, undesirable mirror curvature due to residual thermal stress is controlled without adversely affecting the image quality. In addition, the support structure makes the complete mirror area usable which otherwise is not possible in devices that rely on isotropic silicon etching. A high actuator efficiency with static displacement per unit power of 2.08 μm/mW was achieved due to the reduced thermal capacitance at the actuator legs, when using a 700 nm thin structural layer of SiO2. The resulting scanning mirror achieves open loop time constant as small as 3.42 ms with both thermal and mechanical bandwidths exceeding 100 Hz. Mirror surface non-idealities related to the mirror structure and their influence on image quality are discussed. Sample 3D multi-photon images captured by performing remote scanning in both lateral and axial direction on a benchtop testbed are presented. The efficacy of remote axial scan is ascertained by comparisons with images obtained by moving specimens relative to the objective.

Material‐mediated cell immobilization technology in the biological fermentation proces

AbstractCell immobilization technology has shown much potential in the field of biological fermentation owing to its simple operation, maintenance of long‐term cell viability, repeatability, good stability, and high tolerance. Compared with free‐cell fermentation, immobilized cells show strong growth and metabolism performance in complex environments, such as environments with low pH, or with high concentrations of substrate and product. The metabolic properties of immobilized cells mainly depend on the carrier materials. In recent years, polymer membrane materials have attracted much attention because of their good mechanical properties and flexible support structure. In addition to improving the activity and stability of immobilized cells, biocompatibility modification can also be carried out on the surface of the carrier, which can reduce specific non‐biological interactions between the cells and the carrier. In this review, current advances in cell immobilization using different materials in the field of biological fermentation are reviewed. Perspectives on immobilized cells and the challenges associated with them in the field of biological fermentation are also addressed. © 2021 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

High‐Displacement, Fiber‐Reinforced Shape Memory Alloy Soft Actuator with Integrated Sensors and Its Equivalent Network Model

For soft robotics, shape memory alloy (SMA)‐based elastomeric actuators are a promising material combination but their maximum stroke is limited by the small inherent contraction of SMAs. In this work, a textile‐reinforced soft actuator is presented, which has additional SMA wire length included in the textile structure as well as a sensoric textile to track the actuator's pose. This strategy eliminates the need for external SMA wires with extra mechanical components. Various experiments with different excitation voltages are performed to show the actuator's performance. In a horizontal setup, the soft actuator reaches a bending angle of 270° at a power input of 18 W. The integrated sensor reflects the actuator's position but is also influenced by the temperature increase during activation. Moreover, an equivalent circuit model is proposed that includes the actuator, sensor, and mechanical support structure in one model. The model incorporates not only the mechanical but also the thermal and electrical domains. The simulation results are in good agreement with the experimental results.

Fabrication method of micromachined quartz glass resonator using sacrificial supporting structures

In this study, a novel fabrication method of quartz glass resonators is proposed. The resonators are mechanically supported by Au posts, which are also used as bonding material between the quartz glass device layer and the substrate. The mechanical supporting structures consist of anchor structures and sacrificial supporting structures. The anchor structures remain to support the fabricated resonators during operation while the sacrificial supporting structures are removed during the release process of the resonator. The sacrificial supporting structures were employed to mechanically support the fragile resonator structure during the whole fabrication process. The supporting structures also played a role to dissipate the generated heat during the plasma process and keep the device layer temperature low. Using the proposed method, micromachined resonators were successfully fabricated on a quartz glass substrate. The maximum process temperature was less than 400 °C, thus the method has a large potential as a mean to fabricate quartz glass microstructures on various kind of substrates including the complimentary metal-oxide semiconductor (CMOS) substrates.

Fabricación de un Concentrador Solar Parabólico Compuesto (CPC) para desinfección de agua de consumo en Comunidades Rurales

This paper presents the selection of supply materials and describes the manufacturing process of a solar compound parabolic solar concentrator (CPC) to disinfect drinking water for consumption by rural communities. The volume of water to be treated is 100 liters/day, average amount of water for services of a family of 6 people, including washing of kitchen utensils and food preparation. The selection of supply materials for the CPE manufacture was made considering the lifetime, low cost and availability in the Mexican industrial market. The main components of the CPC are: 1. the profile of the involute, made of galvanized steel sheet gauge 20 (0.9 mm) with bright chrome finish to achieve a reflective surface, 2. Hydraulic system, integrated by coupling elements between 6 lines of borosilicate glass tubes of 44 mm outside diameter and 1.6 mm thickness with PVC accessories and 3. Mechanical support structure of the CPC, which was designed with a variable angle, to adjust according to the latitude of the operation site, this was manufactured with industrial processes of pailería and reinforced tubular profile (PTR) of 14 gauge steel (1.9 mm thickness) was used.