Large Loading Capacity Research Articles

Self-locking mechanism for variable stiffness rigid–soft gripper

Pneumatic soft grippers made of silicone have been successfully applied in the industrial field of grabbing fragile objects. But their inherent low stiffness often limits the practical application in scenarios required high stiffness or large load capacity. To expand the application of soft grippers, a self-locking mechanism realized by an exoskeleton structure is proposed in this work. The stiffness, load carrying capacity, and grabbing stability of this soft–rigid grippers can be enhanced in the premise of maintaining sufficient compliance. The resulted rigid–soft gripper has the ability of tuning its stiffness, simply by locking and unlocking the ratchet-and-pawl of the exoskeleton structure. The locking process is automatically implemented with the bending deformation of soft gripper, and the unlocking process is realized quickly by a simple pneumatic unlocking actuator. The stiffness, grasping motion and output force of the gripper are experimentally characterized theoretically and experimentally. And the capability of unlocking actuators is also verified and tested. Experimental results demonstrate that the rigid–soft gripper has a load capacity up to 9 kg. The gripper can achieve quick, flexible and reliable grasping for objects of various dimensions and shapes, with no compressed gas needed for holding. The proposed self-locking mechanism provides a simple but effective method to enhance the performance of soft grippers and simplify the operation for variable-stiffness grasping.

PEMBUATAN ALAT BANTU UNTUK PROSES Bleeding Air Pada Brake System DI UNIT Dump Truck HD465-7R

A dump truck is a medium to long distance carrier where the material carried is loaded by excavators, wheel loaders or shovels. A dump truck is very suitable to be operated in a mining area because of its large load capacity making it very productive. To support dump truck operations, regular maintenance is needed such as general over haul. After completing the general over haul, the next job is the process of bleeding air on the brake system. For bleeding air work in dump truck units, especially HD465-7R, using existing tools is considered ineffective and unsafe so that it can cause problems, namely the release of oil in the form of bursts that can affect the face, especially the eyes and the presence of oil spills that can damage the environment resulting in inefficiency in completion of work. Therefore, it is necessary to make new tools with the aim that the problem can be resolved. The method used is seven up ++ innovation. The results show that the tools made for the process of bleeding air are effective and safe to use so that the oil that comes out is no longer on the face and there are no oil spills that can damage the environment and the completion of work to be efficient.

A Novel Piezoelectric Stack for Rotary Motion by d 15 Working Mode: Principle, Modeling, Simulation, and Experiments

A novel piezoelectric stack for rotary motion using d 15 working mode is proposed, fabricated, and tested in this article to achieve the high stiffness and high precision of rotation. This piezoelectric stack is fabricated by bonding process from only two components—lead zirconate titanate ceramics and electrodes, which is beneficial to realize the simple structure. A theoretical model based on the shear deformation theory is established to predict the static output performances. And the simulation with the finite-element method is adopted to evaluate the dynamic characteristics. An experimental system is built to verify the design and study the performances of the piezoelectric stack. The experimental results indicate that the static output angle changes from −13.25 to +13.33 μ rad, whereas the exciting voltage changes from −300 to +300 V, with good linear relationship and high repeatability accuracy. Under the condition of changing the exciting voltage by the step of 0.5 V, the stable resolution is measured to be higher than 0.022 μ rad. The large load capacity and width frequency response are verified, which reflect the high stiffness of the proposed piezoelectric stack. The proposed piezoelectric stack achieves accurate and stable rotary output motion with high resolution, rapid response, and large load capacity. Besides, the stack has regular shape and simple structure, and therefore, it is suitable to be integrated in the equipment in the fields of micro–nano manipulations, piezoelectric ultrasonic motors, etc.

Dynamic modeling of a planetary gear system with sun gear crack under gravity and carrier-ring clearance

The large load capacity, compact size and high-power density have made planetary gearboxes widely applied in heavy machinery such as wind turbines. Although well designed, planetary gearboxes are vulnerable to fatigue crack because of harsh working environment such as high loads. Fatigue crack may eventually cause failures of planetary gearboxes if not detected early. This study investigates the dynamics of a planetary gear system with a crack in a sun gear tooth. This paper considers the gravity effect, carrier-ring bearings clearance, gyroscopic and centrifugal forces that reported studies have not considered together yet. Simulation results reveal that gravity produces a sinusoidal shift in the dynamic response of a planetary gearbox in the time domain. The carrier-ring bearing clearance causes crack-induced impulses to be more apparent. These results can help researchers develop more effective fault diagnosis strategies especially for early crack in the sun gear.

Rapid self-disassembly of DNA diblock copolymer micelles via target induced hydrophilic-hydrophobic regulation for sensitive MiRNA detection.

In this work, a novel DNA nanostructure with a shorter assembly time and larger loading capacity was constructed using amphiphilic DNA-alkane group (Spacer C12)10 conjugates encapsulating plentiful fat-soluble fluorescent dyes into the hydrophobic core to form the DNA micelles, which could be rapidly self-disassembled via target induced hydrophilic-hydrophobic regulation to release fluorescent dyes from micelles to the organic phase, realizing the fast and sensitive detection of microRNA.

Effect of AMB winding configurations on static and dynamic performances and power consumptions of the AMB-rotor system

Active magnetic bearings (AMBs) bring extraordinary benefits such as free of contact, elimination of lubrication, active control of rotor position, and a built-in monitoring system. In the design of AMBs, the bearing structure is of significance since it has an important impact on bearing performances. However, the effect of winding configurations of AMBs is still obscure. In this paper, the system-level implications of two radial AMB winding configurations termed the Ortho and the Cross types are investigated, including the bearing characteristics, power consumptions and rotor dynamic behaviors. The simulation results demonstrate that the Cross type contributes to larger load capacity in the direction of gravity. In condition of a heavier gravity load (−200 N), the Cross-type winding configuration saves power consumption with a percentage of 17.2% at steady state (20,000 rpm) and 12.7% considering unbalance mass during the run-up process. However, the rotor vibrations of the Cross type in case of external loads and unbalance mass are larger than the Ortho type. The proposed results of this paper provide some useful information for the AMB winding configuration design.

2-Dimensional Nanomaterials with Imaging and Diagnostic Functions for Nanomedicine; A Review

Abstract In the last several decades, 2-dimensional (2D) nanomaterials have been studied in various bio-fields such as drug delivery systems, diagnostic and imaging materials, etc. In particular, many investigations have been intensively conducted to explore 2D nanomaterials for drug delivery devices such as layered double salts (LDSs), layered rear-earth hydroxides (LRHs), and layered double hydroxides (LDHs) due to their low toxicity, high solubility in body fluid, high tumor targeting efficiency, large drug loading capacity, etc. However, only a few reports have been made to date on diagnostic and imaging effects on those 2D nanomaterials. In this review, therefore, an attempt is made to underline how important such 2D nanoparticles would be applicable for optical imaging, magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), positron emission tomography (PET), computed tomography (CT), etc., and to discuss on their potential molecular imaging modalities for image-guided and precision therapy as well.

Mesoporous silica induces hippocampal neurons cell autophagy through AMPK/mTOR/P70S6K signaling pathway.

Mesoporous silica is a drug carrier with strong targeting, large loading capacity, and easy modification of its surface while its toxicity draws increasing attention recently. In this study, we evaluated the impact of SBA-15 nanomaterials on hippocampal neurons. We found that SBA-15 induces oxidative damage to hippocampal neurons HT22, which further activates autophagy. Treatment with the mammalian target of rapamycin (mTOR) inhibitor AZD8055, the phosphorylation level of mTOR and P70S6K reduced and increased levels of p-AMPK meaning that the adenosine-activated protein kinase (AMPK)/mTOR/P70S6K pathway is involved in SBA-15 induced autophagy of HT22. These results suggested that mesoporous silica material SBA-15 might affect central nervous cells via oxidative stress activation of the AMPK/mTOR/P70S6K pathway, which provides a theoretical basis for safe administration of such materials in patients.

NH2-MIL-53(Al) Metal-Organic Framework as the Smart Platform for Simultaneous High-Performance Detection and Removal of Hg2.

The worsening pollution due to mercury species makes it inevitable to explore prospective versatile materials, which not only can detect mercury ions (Hg2+) with high sensitivity but also possesses efficient capture and removal ability. In this study, a series of classic organic ligand-based luminescence MOFs materials with high oxidation state central metals (Al3+, Zr4+, Cr3+, Fe3+, and Ti4+) were synthesized and were screened to achieve simultaneously Hg2+ detection and removal through the strong coordination of amino groups or nitrogen centers with Hg2+ and the intrinsic fluorescence intensity of MOFs regulated by the ligand-to-metal charge transfer (LMCT) effect. Among these checked materials, NH2-MIL-53(Al) exhibited the excellent ability for Hg2+ detection with wide response interval (1-17.3 μM), low detection limit (0.15 μM), good selectivity, wide pH adaptation (4.0-10.0), and strong anti-interference ability. Meanwhile, the resultant NH2-MIL-53(Al) possessed an efficient removal capability toward Hg2+, accompanied by a fast uptake kinetics (within 60 min) and large loading capacity (153.85 mg g-1). Furthermore, NH2-MIL-53(Al) also displayed satisfactory stability before and after Hg2+ treatment because of the formation of strong coordination bonds between high oxidation state aluminum (Al3+) and organic carboxylate ligands. Notably, the prepared NH2-MIL-53(Al) had no significant loss of adsorption performance even after being reused four times. All of these superior properties render the smart NH2-MIL-53(Al) nanohexahedron a great potential for simultaneous Hg2+ detection and removal from water.

Engineering Biocoatings To Prolong Drug Release from Supraparticles.

Supraparticles (SPs) assembled from smaller colloidal nanoparticles can serve as depots of therapeutic compounds and are of interest for long-term, sustained drug release in biomedical applications. However, a key challenge to achieving temporal control of drug release from SPs is the occurrence of an initial rapid release of the loaded drug (i.e., "burst" release) that limits sustained release and potentially causes burst release-associated drug toxicity. Herein, a biocoating strategy is presented for silica-SPs (Si-SPs) to reduce the extent of burst release of the loaded model protein lysozyme. Specifically, Si-SPs were coated with a fibrin film, formed by enzymatic conversion of fibrinogen into fibrin. The fibrin-coated Si-SPs, FSi-SPs, which could be loaded with 7.9 ± 0.9 μg of lysozyme per SP, released >60% of cargo protein over a considerably longer period of time of >20 days when compared with the uncoated Si-SPs that released the same amount of the cargo protein, however, within the first 3 days. Neurotrophins that support the survival and differentiation of neurons could also be loaded at ∼7.3 μg per SP, with fibrin coating also delaying neurotrophin release (only 10% of cargo released over 21 days compared with 60% from Si-SPs). In addition, the effects of incorporating a hydrogel-based system for surgical delivery and the opportunity to control drug release kinetics were investigated-an alginate-based hydrogel scaffold was used to encapsulate FSi-SPs. The introduction of the hydrogel further extended the initial release of the encapsulated lysozyme to ∼40 days (for the same amount of cargo released). The results demonstrate the increasing versatility of the SP drug delivery platform, combining large loading capacity with sustained drug release, that is tailorable using different modes of controlled delivery approaches.

Role of bacterial minicells in cancer therapy

Cancer is one of the most important diseases threatening human health. Frequently-used traditional cancer treatment methods, like radiotherapy, chemotherapy and surgery, have serious toxic side effects and limitations. The widely-used drug delivery carriers (liposomes, nanoparticles, etc.) have also possessed many issues such as drug leakage and incomplete loading in the late clinical stage. Currently, using tumor-targeting vectors to deliver anti-tumor drugs or small molecules is one of the promising strategies for mediating safe and effective tumor therapy. In recent years, bacterial-derived non-replicating minicells, which are nanoscale non-nucleated cells produced during abnormal bacterial division, have got more and more attention. With a diameter of 200-400 nm, minicells have a large drug loading capacity. Meanwhile, the surface of minicells are able to be modified to load the assembly of antibodies/ligands that bind to tumor cell surface specific antigens or receptors, which can significantly improve tumor targeting of minicells. This tumor-targeting nanomaterials of minicells not only are used to deliver anti-tumor chemotherapeutic drugs, functional nucleic acids or plasmids encoding functional small molecules to mammalian cells, but also greatly increase drug loading and reduce drug penetration. Thus, the use of minicells combining with chemical therapy could help reduce the toxicity and maximize the effectiveness of the drug in the body. This paper summarizes the research and development of production purification, drug loading, tumor cells targeting, and internalization process of minicells, as well as its use in the delivery of anti-tumor drugs, to provide some information for the development and utilization of minicell carriers.

Gated Mesoporous Silica Nanocarriers for Hypoxia-Responsive Cargo Release.

Mesoporous silica nanocarriers (MSNs) are appealing in terms of their large cavity surface area and high loading capacity, but they have been suffering from premature cargo release. Herein, we report a gated smart MSN that is sensitive to low oxygen concentration (i.e., hypoxia) via taking advantage of the superior electron-accepting ability of the azobenzene moiety. The azobenzene polymer was employed as the responsive gate-keeper that was deposited on the MSN surface, followed by coating with amphiphilic Pluronic F68 for steric stabilization. The obtained nanocarriers were less than 200 nm. The in vitro polymer degradation was spectrophotometrically witnessed via the employment of a reducing agent, namely, sodium dithionite, with astrong electron-donating ability. The hypoxia-responsive cargo release from the gated MSN was quantitatively demonstrated in breast cancer cells (MCF-7) using the fluorescence resonance energy transfer (FRET) technique where coumarin 6 and rhodamine B was selected as the FRET donor and acceptor, respectively. The FRET ratio was used as the index and decreased linearly over time under hypoxia, whereas it almost remained steady under normoxia. In addition, a model photosensitizer, namely, chlorin e6, was also loaded in the gated MSN whose toxicity under hypoxia was verified. This study developed a hypoxia-responsive MSN with the azobenzene polymer as the removable gate-keeper, which would expand the application of MSNs in pharmaceutical and biomedical areas since thelow oxygen concentration is a unique trigger in many pathological conditions.

Bioinspired Variable Stiffness Dielectric Elastomer Actuators with Large and Tunable Load Capacity.

This article proposes a bioinspired variable stiffness dielectric elastomer actuator (VSDEA) that is inspired by the leaf habit of monocots. The VSDEA is a fully flexible strip with a curved cross section and a tip dielectric elastomer minimum energy structure (DEMES). An arc fixture is used to clamp the strip that imitates the connection mode between the leaf and the cylindrical stem of the monocot. When applying voltage on the tip DEMES, the transverse curvature of the strip is changed, and then, the bending stiffness of the VSDEA can be tuned. Effects of applied voltage and important design parameters on the bending behavior of the VSDEA are experimentally studied in detail. The results show that the bending stiffness of the VSDEA approximately decreases linearly with the increase of applied voltage, which is very advantageous for stiffness control. The load capacity of the VSDEA is enhanced due to the bioinspired clamping mechanism and can be tuned by the applied voltage. It can also be found from the tested VSDEA prototypes that, when the applied voltage ranges from 0 V to 5.6 kV, the maximum relative stiffness and critical load changes reach about 71.8% and 75.6%, respectively. The maximum stiffness and critical load are, respectively, 157.8 N/m and 889.9 mN, which are two orders greater in magnitude than general DEMESs; as a result, this VSDEA can bear a payload 139 times its weight. It demonstrates that the bioinspired VSDEA can be useful for soft robots, vibration control, and morphing applications.

Design, analysis, experiments and kinetic model of a high step efficiency piezoelectric actuator

This paper proposes a novel linear stick-slip piezoelectric actuator with compact structure and a dual-functional flexure hinge mechanism, which can realize motion of high step efficiency, high speed and precision. The flexure hinge mechanism is used in the actuator for realizing parasitic motion and amplifying the displacement of the piezo stacks to enhance the motion performance of the actuator. The structure and the operating principle is described in detail. The pseudo-rigid-body method and the finite element analysis method are adopted in the design process. A series of experiments are carried out based on a manufactured prototype to prove the validity of the proposed actuator, and motion parameters of the prototype are obtained. The resolution of the prototype is 0.594 µm, the largest velocity is 0.742 mm/s, the largest load capacity is 3.6 kg and the largest step efficiency is 0.934. And a valid kinetic model is established for further investigation and design guide.

Design and DOF Analysis of a Novel Compliant Parallel Mechanism for Large Load.

The degree of freedom (DOF) and motion characteristics of a kind of compliant spherical joint were analyzed based on the screw theory, and a new design scheme for force-inversion of the compliant spherical joint was proposed in this paper. A novel type of six DOF compliant parallel mechanism (CPM) was designed based on this scheme to provide a large load capacity and achieve micrometer-level positioning accuracy. The compliance matrix of the new type of CPM was obtained through matrix transformation and was then decomposed into its generalized eigenvalues. Then, the DOF of the mechanism was numerically analyzed based on the symbolic formulation. The finite element analysis model of the compliant parallel mechanism was established. The static load analysis was used to verify the large load capacity of the mobile platform. By comparing the deformation obtained by the compliance matrix numerical method with the deformation obtained by the finite element method, the correctness of the compliance matrix and the number of the DOF of the CPM was verified.

A New Glioblastoma Targeting Therapy Concept by Using Square Shaped Janus Drug Carrier Assisted with 3D Printed External Magnetic Wearables

AbstractAt present, the clinical treatment of malignant glioma is still unsatisfactory. The existence of the blood–brain barrier hinders most chemical and biological drugs to reach the brain tissue. In this study, a square‐shaped Janus drug carrying system, which incorporated with high infrared responsiveness, large drug loading capacity, and reliable magnetic targeting capabilities is synthesized. Combined with an external 3D printed magnetic wearable equipment, this carrying system can effectively penetrate the blood–brain barrier in both in vitro and in vivo tests, it is thus applied to two different targeting tumor therapies (including glioma). Animal experiments demonstrate the multiple therapeutic effects of the proposed system. The subsequent studies imply that the obtained carrier has no obvious toxic effects on the organs of animals. Different from the classical biochemical targeting method, this study uniquely combines the porous Janus nanocarrier with an external wearable magnetic guidance device (physical targeting), which is a promising target therapeutic concept with impressive flexibility and reliability.

Metal-Organic Frameworks as Drug Delivery Platforms for Ocular Therapeutics.

Metal-organic frameworks (MOFs) have been evaluated as potential nanocarriers for intraocular incorporation of brimonidine tartrate to treat chronic glaucoma. Experimental results show that UiO-67 and MIL-100 (Fe) exhibit the highest loading capacity with values up to 50-60 wt %, whereas the performance is quite limited for MOFs with narrow cavities (below 0.8 nm, for example, UiO-66 and HKUST-1). The large loading capacity in UiO-67 is accompanied by an irreversible structural amorphization in aqueous and physiological media that promotes extended release kinetics above 12 days. Compared to the traditional drawbacks associated with the sudden release of the commercial drugs (e.g., ALPHAGAN), these results anticipate UiO-67 as a potential nanocarrier for drug delivery in intraocular therapeutics. These promising results are further supported by cytotoxicity tests using retinal photoreceptor cells (661W). Toxicity of these structures (including the metal nodes and organic ligands) for retinal cells is rather low for all samples evaluated, except for HKUST-1.

Mesoporous Silica Materials as Drug Delivery: "The Nightmare" of Bacterial Infection.

Mesoporous silica materials (MSM) have a great surface area and a high pore volume, meaning that they consequently have a large loading capacity, and have been demonstrated to be unique candidates for the treatment of different pathologies, including bacterial infection. In this text, we review the multiple ways of action in which MSM can be used to fight bacterial infection, including early detection, drug release, targeting bacteria or biofilm, antifouling surfaces, and adjuvant capacity. This review focus mainly on those that act as a drug delivery system, and therefore that have an essential characteristic, which is their great loading capacity. Since MSM have advantages in all stages of combatting bacterial infection; its prevention, detection and finally in its treatment, we can venture to talk about them as the “nightmare of bacteria”.

Development of “4E” Levelriver-Sea-Going Ship

Abstract In order to effectively promote the construction of the Yangtze River economic belt, it has become China’s national strategy to vigorously develop the river-sea-going transportation. In the present paper, theoretical analysis, numerical simulation and model test are combined together to develop flat-type river-sea-going ship which is characterized with larger loading capacity, lower fuel consumption, better performance on energy-saving and environmental-friendly, excellent economy and higher transportation efficiency. Key technologies on hydrodynamic performance, structural safety, energy-saving technology and green ship technology are investigated to develop the river-sea-going ship. The developed “4E” level ship has great significance to the implementation of national strategic deployment.

Behavior of Cantilever Beams in R.C. Frames with Effect of Steel Fibers in Beam – Column Joint

This paper aims at investigating the behavior of cantilever beam in reinforced concrete frame modified by steel fibers. The study depends on adding steel fibers at the joint of beam column section to improves the ductility of the beam – column joint. Steel fibers of ratio (0.5%) and (1%) steel fibers by volume added for two specimens comparing with two others cast without steel fibers joint in R.C. frame. The cantilever frame behavior at applied load will be discussed in this study. The load applied to the frame at the edge of cantilever arms. The test results showed that the difference between the monolithic frame is larger in ultimate loads compared with non￾monolithic, and the frame with 1% steel fibers have large load capacity compared with 0.5% steel fibers frame. The frame which cast monolithically shows highest resistance among the three other frames in ultimate load and flexural deformation, after load was applied to the four specimens the behavior of the frame up to the failure occurred in the beam-column joint at exterior face of the cantilever. beside studying the effect of steel fibers percentage and behavior of beam column joint, this study focuses also on investigating the difference between monolithic and non-monolithic concrete elements