Multi-chamber Structure Research Articles

Enhancement of soil ecological remediation using a hydrogel material constructed by freeze–thaw driving force

Composite polymer materials as soil improvers are developed to enhance soil cohesion and aggregate stability. However, the improved soil still struggles to overcome the reduction in strength caused by day-to-day freeze–thaw (FT) cycle in the plateau area with large temperature difference. In this study, the natural power of FT cycle was used to drive the crosslinking of poly (vinyl alcohol) (PVA) and sodium alginate (SA) to form the interpenetrating networks of PVA-SA hydrogel. Then, this hydrogel was applied to stabilize the soil. The characterizations by FTIR, TGA, SEM and XRD indicated that the PVA-SA hydrogel had a porous, multi-channel and multi-chamber structure. Under the action of FT driving force, a series of studies including physical, chemical, water retention, direct shear, permeability, and aggregate stability were carried out on the soil with hydrogel applied. Compared to the control group, the data indicated that the cohesion of soil is significantly improved to 80 kPa. And the saturated hydraulic conductivity of the soil was reduced to 1/45 of the pre-modification rate, which had a positive impact on the water retention of the soil. What’s more, the results revealed that the PVA-SA hydrogel had effects on the aggregate stability, the submerged soil with added PVA-SA hydrogel still had no sign of disintegration and its mass percentage was greater than 99 % after 70 days. In a word, this composite material can effectively improve the cohesion and aggregate stability of the soil with the help of natural driving forces, which is potential to be used as remediation material for the plant layer in ecological restoration process.

Advanced electrochemical membrane technologies for near-complete resource recovery and zero-discharge of urine: Performance optimization and evaluation

The depletion of nutrient sources in fertilizers demands a paradigm shift in the treatment of nutrient-rich wastewater, such as urine, to enable efficient resource recovery and high-value conversion. This study presented an integrated bipolar membrane electrodialysis (BMED) and hollow fiber membrane (HFM) system for near-complete resource recovery and zero-discharge from urine treatment. Computational simulations and experimental validations demonstrated that a higher voltage (20 V) significantly enhanced energy utilization, while an optimal flow rate of 0.4 L/min effectively mitigated the negative effects of concentration polarization and electro-osmosis on system performance. Within 40 min, the process separated 90.13% of the salts in urine, with an energy consumption of only 8.45 kWh/kgbase. Utilizing a multi-chamber structure for selective separation, the system achieved recovery efficiencies of 89% for nitrogen, 96% for phosphorus, and 95% for potassium from fresh urine, converting them into high-value products such as 85 mM acid, 69.5 mM base, and liquid fertilizer. According to techno-economic analysis, the cost of treating urine using this system at the lab-scale was $6.29/kg of products (including acid, base, and (NH4)2SO4), which was significantly lower than the $20.44/kg cost for the precipitation method to produce struvite. Excluding fixed costs, a net profit of $18.24/m3 was achieved through the recovery of valuable products from urine using this system. The pilot-scale assessment showed that the net benefit amounts to $19.90/m3 of urine, demonstrating significant economic feasibility. This study presents an effective approach for the near-complete resource recovery and zero-discharge treatment of urine, offering a practical solution for sustainable nutrient recycling and wastewater management.

Constructing labyrinth structure in molecularly imprinted composite membranes for efficiently separating acteoside

Molecular imprinted composite membranes (MICMs) had attracted much attention in the field of selective separation for bioactive components of natural products. However, it remained a challenge to improve the separation performance of MICMs. Herein, multi-chamber carbon cubes (MCCBs) were synthesized and introduced into polyvinylidene fluoride (PVDF) powders to construct labyrinth structure in molecularly imprinted composite membranes (LMICMs), which were used for efficiently separating acteoside (ACT). The constructed labyrinth structure had complex multidimensional transport routes to trap abundant ACT molecules in LMICMs, thereby improving the rebinding capacities and permselectivity of LMICMs. Meanwhile, the prepared MCCBs with multi-chamber structure can provide a great accommodation space, improving the rebinding capacities of LMICMs. In addition, the labyrinth structure with the large interface resulted in the creation of numerous ACT-imprinted sites and cavities (ACT-ISC) in LMICMs, thus increasing the permselectivity of LMICMs to ACT. Importantly, it was no surprise that large rebinding capacity (154.74 mg/g), excellent rebinding selectivity (4.52) and high permselectivity (14.88) were successfully achieved. It was of great value to design LMICMs with labyrinth structure for efficiently separating of bioactive components from natural products.

Optimization of quenching characteristics of a multi-chamber arrester

Lightning is a major cause of tripping faults in overhead transmission lines. Multi-chamber lightning arresters are widely used to protect high-voltage lines from lightning because of their reliable arc-quenching performance. This paper analyzes the development and quenching process of an arc after a lightning breakdown arrester and studies the quenching mechanism of a multi-chamber arc structure based on its structural characteristics. We built an impulse-current test platform and carried out an impulse-current test for the multi-chamber arrester. The arc motion was captured by a high-speed camera, and the height, speed, and temperature of the arc ejection were obtained by signal processing. The multi-chamber arrester structure is optimized by using the maximum arc ejection height and the maximum ejection speed as metrics to find the optimal combination of the quenching-hole diameter and depth and the gap distance of the multi-chamber structure.

RESIDENTIAL HOUSES OF THE NORTH-WESTERN CRIMEA IN THE LATE SCYTHIAN PERIOD: BASIC LAYOUT PATTERNS AND ANALOGIES

The article summarizes the study of the layouts of houses built on the northwestern coast of the Crimea in the last quarter of the 2nd century BC – early 2nd century AD. Particular attention is paid to changes in the main layout patterns, as well as the search for their analogies. The author analyzes 28 layouts of the best preserved Late Scythian houses. All of them are multi-chamber structures, most of them have courtyards. The main layout patterns differ in the location of the premises with respect to the courtyard. It was possible to determine periods of dominance of certain patterns. The layouts of Late Scythian houses in the North-Western Crimea become more complicated with time. However, in addition to the “internal evolution”, residential construction also experiences a strong influence of classical architecture, which manifests itself at different stages. There is also a connection with other regions of the Crimean Scythia.

A bionic multi-chamber pneumatic actuator for powered exoskeleton based on muscle scale mechanism

AbstractIn order to solve the problems of low loading capacity and low driving efficiency for the powered exoskeleton, this paper presents a bionic multi-chamber pneumatic actuator based on muscle scale mechanism. Firstly, the bionic muscle scale mechanism and multi-chamber structure design for the novel pneumatic actuator are introduced. Afterward, the driving characteristics of the multi-chamber actuator are analyzed theoretically, including analysis of output force and analysis of energy efficiency. Then, the load matching control strategy for the novel actuator is optimized, and the load matching performance, displacement tracking accuracy, and energy efficiency are studied by simulation. Finally, the prototype of the multi-chamber actuator is developed, and the exoskeleton testing platform is built, experiment and discussion are conducted for the driving characteristics, which realized the high energy efficiency and the feasibility of load matching.

Effects of gelation on the stability, tribological properties and time-delayed release profile of double emulsions

Due to the unique multi-chamber structure of the double emulsion (DE), gelation different compartments of double emulsions with different gelling strength offers flexible control over their encapsulation and delivery properties. Herein, the aqueous or oil phase of DE was gelled with alginate or beeswax at different gelling strength, and the effects of gelation on the processing stability, rheological and tribological properties as well as the digestion profile of double emulsions were investigated. Gelation in each phase improved the stability of DE (0,0,0), with the oil or external aqueous phase gelation being more efficient in lifting the encapsulation stability after 14 days’ storage (increased from 67.50 ± 2.47% to 86–90% and 84–90%, respectively). Under processing conditions, the oil phase gelled DE was easily destabilized when subjected to heating treatment, but maintained better stability under freeze-thaw or osmotic pressure treatment compared to the internal and external water phase gelled ones. Gelation also actively regulated the rheological and tribological properties of DE, wherein gelation in internal water phase showed the least impact on the rheological properties, gelation in the external aqueous phase and oil phase exerted more significant influence on the viscosity and the tribological properties of DE, respectively. The external water phase gelled DE manifested the time-delayed digestion profile with only 8.09 ± 0.12% of internal marker release at the end of gastric digestion and the FFA release extent was decreased by 41.66% as compared to the DE (0,0,0). The present study offers a valuable guide for rational design of double emulsions with tailor-made processing stability, oral sensation and digestive characteristics.

Competition among Refined Hollow Structures in Schiff Base Polymer Derived Carbon Microspheres.

Synthetic polymer-derived hollow carbon spheres have great utilitarian value in many fields for which the synthesis of proper polymer precursors is a key process. The exploration of new suitable polymer precursors and the construction of refined hollow structures in emerging polymers are both of great significance for synthetic methodology and novel carbon materials. Here, for the first time Schiff base polymer (SBP) colloid spheres with refined hollow structures were synthesized by tandem gradient growth and confined polymerization processes. The Hill equation was employed as a mathematical model to explain the gradient growth of SBP spheres. The size-dependent inner structure of SBP spheres can be adjusted from hollow to multichamber-surrounded hollow, and then to a multichamber structure. SBP-derived carbon spheres having similar surface area and chemical composition but different inner structures provide an effective way to investigate the relationship between inner structure and performance.

Interface functional groups protected by confinement effect for flexible supercapacitor and capacitive deionization

Biomass, as one of the most promising carbon precursors, mainly focuses on its special original nanostructures at present. However, the biological diversity and uncontrollability are not conducive to its application in high-precision fields. In this work, the biomass, separated into soluble substances, are applied to the multi-cavity nanospheres (NC-PPD) and ultra-thin nanosheets (BC-PPD) modified by functional group (p-phenylenediamine) interface, thus without depending on their original morphology. On account of similar carbon components from the same precursor, the single-factor function relation, the confinement effect on surface functional groups and its influence law in flexible supercapacitor (SC) and capacitive deionization applications, are studied in detail. Overall, the interface modification optimizes the hydrophilicity of the material, increases its actual reachable specific surface area and pseudocapacitance contribution. Most importantly, the confinement effect enhances the stability of surface functional groups, and reduces the material damage from capacitive reaction (retains 80.2% initial capacitance after 104 cycles). Moreover, the multi-chamber structure strengthens the material stability and alleviates the adverse effects of material breakage. For SC, the NC-PPD//NC-PPD device provides large energy density of 8.8 Wh kg−1 and maximum power density of 2.5 k W kg−1. For CDI, salt adsorption capacity can be up to 33.2 mg g−1.

Nanoengineering of N-doped Mesoporous Carbon Nanoparticles with Adjustable Internal Cavities via Emulsion-Induced Assembly.

The preparation of mesoporous carbonaceous materials with particularly adjustable morphology is currently a hot area of research in mesoporous materials. Herein, a novel approach is reported for the construction of N-doped multicavity mesoporous carbon nanoparticles (NMMCNs) based on the “emulsion swelling–acid curing mechanism” using a nanoemulsion assembly method under a high-speed shearing force. Intriguingly, this approach adopted a novel acid (HCl) curing procedure. Impressively, the morphology evolution from an internal multicavity to a single cavity and then to a non-cavity interior structure could be accomplished by simply varying the synthesis parameters. Additionally, this synthesis approach ingeniously overcame the following problems: (i) technically, the employment of high temperatures and high pressures in traditional hydrothermal reaction curing environments is avoided; (ii) this approach removes the requirement for silicon coating, which provides a limited pyrolysis condition, to obtain a multi-chamber structure. Resveratrol (Res) is an insoluble natural medicine and was successfully loaded into NMMCNs, thereby the Res–NMMCNs delivery system was constructed. Importantly, the Res–NMMCNs delivery system could still retain the antitumor and antioxidant activity of Res in vitro.

Effect of Ageing on Self-Healing Properties of Asphalt Concrete Containing Calcium Alginate/Attapulgite Composite Capsules.

Calcium alginate capsules within asphalt concrete can gradually release interior asphalt rejuvenator under cyclic loading to repair micro cracks and rejuvenate aged asphalt in-situ. However, asphalt pavement will become aged due to environmental and traffic factors during the service period. In view of this, this paper investigated the effect of ageing on the healing properties of asphalt concrete containing calcium alginate/attapulgite composite capsules under cyclic loading. The capsules were fabricated using the orifice-bath method and the morphological structure, mechanical strength, thermal stability, oil release ratios and healing levels of capsules in fresh, short-term ageing and long-term ageing asphalt concrete were explored. The results indicated that the different ageing treatments would not damage the multi-chamber structure nor decrease the mechanical strength of capsules but would induce the capsules release oil prematurely. The premature oil released from capsules in turn can offset the ageing effect owing to ageing treatment. The short-term ageing and long-term ageing plain asphalt mixtures gained strength recovery ratios of 39.3% and 34.2% after 64,000 cycles of compression loading, while the strength recovery ratios of short-term ageing and long-term ageing asphalt mixtures containing capsules were 63.5% and 54.8%, respectively.

Fire Resistance of Aluminum-Glass Partitions with a Parallel Structure of Intumescent Layers

Aim: The aim of the article is to verify the fire resistance of aluminum-glass construction partitions with a parallel structure. The paper presents the results of tests in a fire chamber of a selected partition, a leading national manufacturer of aluminum-glass systems. The results of the fire tests were used to validate a simple parallel model of the reliability of non-renewable systems. Introduction: Fire-retardant properties of partitions made of glass and aluminum profiles determine their ability to stop the spread of fire by clos - ing the fire in separate zones. Fire resistance of such partitions is measured according to various criteria, in particular the requirements concern: stability R (glass does not break), tightness E, radiation limitation W and insulation I. The tightness requirement E means that the partition effectively protects the fire compartment against flames, smoke and hot gases. The insulating postulate I means that the average temperature of glass and the profiles on the surface of the partition on the protected side does not exceed the contractual value during the nominal duration of the fire. The measure of fire resistance of a partition is time t, expressed in minutes, in which the structure of an aluminum-glass partition meets one or more of the criteria listed. Methodology: The experimental database consists of the results of routine fire resistance tests of system building partitions obtained in the certification process of selected facade systems. Interpretation of the obtained results of laboratory tests was based on simple models of reliability of non-renewable systems. Conclusions: The graphs of average temperature increase on the outer surface of the tested glass are the same in each case in terms of quality and quantity. Up to about 70% of the nominal fire resistance, the temperature increase is linear, followed by a non-linear phase according to a concave curve. The course of the temperature-rise curves on the outer surface of aluminum profiles is qualitatively different. The graphs are non-linear, convex from the beginning of heating, with the inflection point reached after about 20 minutes of the test. The obtained results may indicate that the multi-chamber structure of aluminum profiles does not ensure a parallel reliability structure, because the object has a quasi-parallel structure. The presented results of the temperature-rise curves and their reliability interpretation require confirmation in further laboratory tests of aluminum-glass partitions with a different structure of panes and profiles. Keywords: glass, partitions, laboratory tests, fire resistance, reliability Type of article: case study

Encapsulation of Ultrafine Metal–Organic Framework Nanoparticles within Multichamber Carbon Spheres by a Two-Step Double-Solvent Strategy for High-Performance Catalysts

Carbon-encapsulated metal-organic framework (MOF) composite is one kind of emerging new catalyst with high efficiency and has gained much attention. However, for this kind of composite catalyst, the key to improving its catalytic activity and durability is to realize the effective dispersion of MOF nanoparticles (NPs) and enhance the interaction between MOF NPs and the carbon matrix, which remain a significant challenge. Herein, ultrafine MOF NPs within multichamber carbon spheres (MOF@MCCS), for the first time, have been rationally synthesized by a two-step double-solvent strategy for high-performance catalysts. The precise loading of guest MOFs can be achieved by adjusting the multichamber structure and calcination extent of the multichamber polymer (MCP), and the particle size of MOFs can be as low as 13.2 nm. Due to the formation of abundant carbon defects in the pyrolysis process of MCPs, the special structure and synergistic effect make the material exhibit higher catalytic activity and durability. More importantly, this method is universal and can be extended to different MOF systems. The two-step double-solvent strategy not only prepares a unique structure of MOF@MCCS-type host-guest-encapsulated catalysts but also provides a new idea for the design of high-efficiency catalysts with better performance and higher durability.

Simultaneously Monitoring the Metabolic Activity of Three Bacteria Utilizing a LAPS-Based Differential Sensor Set-up

Introduction On-line monitoring of the metabolic response of microorganisms can avoid costly and time-consuming disturbances at different stages in biofermentation processes. For instance, process downtimes in biogas plants caused by metabolically inactive microorganisms can induce irreversible hindrances and cost-intensive interventions, which can be prevented by utilizing an efficient monitoring system. A LAPS (light-addressable potentiometric sensor) can be a promising candidate for those monitoring systems, since it combines several advantages such as small size, possibility of mass fabrication, solid-state nature and short response time [1,2]. In general, LAPS with an appropriate recognition layer provides a spatially resolved detection of a certain analyte and can record 2D-chemical images of concentration changes of bio/chemical species on its flat surface [3]. In this work, a LAPS-based multi-chamber measuring system with 16 laser-diode modules was utilized as shown in Fig. 1 (left), which allows to simultaneously determine the extracellular acidification of three microorganisms: Escherichia coli (E. coli) K12, Corynebacterium glutamicum (C. glutamicum) ATCC13032, and Lactobacillus brevis (L. brevis) ATCC14869. With the knowledge about the acidification behavior of each microorganism in a multivariate-type analysis, a signal-response pattern can be obtained. In this context, the sensor signal and the status of the biofermentation process can be correlated. Materials and Methods Bacterial cultures were prepared and resuspensioned in phosphate-buffered saline (PBS) solution (0.2 mM/pH, pH 7.4). Different glucose concentrations were adjusted. A four-chamber LAPS measuring system was deployed for differential measurements, as assembled in Fig. 1. First, all four chambers were loaded with 100 μl of glucose solution, varying in each experiment between 0.042 mM and 5.0 mM. The salt bridge chamber was filled with 1 ml of 3 M KCl and was immersed into the four chambers, passing the bias voltage through a Ag/AgCl reference electrode to the sensor surface, containing the glucose solution. After a conditioning phase of 10 min with the particular glucose concentration, cells (200 µl) were added to the respective chambers. Chamber 1 was loaded with E. coli, chamber 2 with C. glutamicum and chamber 3 with L. brevis bacteria. Chamber 4 served as the reference chamber without cells containing only the diluted PBS solution. Four LDMs were considered for each chamber to read-out the sensor signals. The mean value of each chamber was used for further evaluations [4]. Results and Conclusions Fig. 1 (right) depicts exemplary the metabolic responses as correlation curves between the LAPS signal and various glucose concentrations for the three types of investigated bacteria at a constant cell number of 4.8 × 109 cells/ml. The black curve refers to the extracellular acidification of E. coli, the red curve to C. glutamicum, and the green one to L. brevis bacteria. It was observed that by increasing the glucose concentration, the overall cellular metabolism increases due to an increase of H+-ion activity on the pH-sensitive transducer layer of the LAPS chip during the acidification phase. The obtained results will be discussed in context of varying cell numbers as well as status of a selected biofermentation process.Fig. 1. Schematic illustration of four-chamber differential LAPS set-up (left). RE: Ag/AgCl reference electrode, SC: sealing cap, SB: salt bridge chamber, MC: multi-chamber structure fixed on the sensor surface; LAPS consisting of layer structure of Al/p-Si/SiO2/Ta2O5 and modulated light source (LS) based on 16 laser-diode modules; 1–3: active sensor chambers with cells; 4: reference sensor chamber without cells; Iphoto: photocurrent; Vbias: bias voltage; AC: alternating current; LDMs: laser-diode modules. Correlation curves between LAPS signal response and glucose concentration (right). Mean values and standard deviations of potential change values of E. coli (black), C. glutamicum (red), L. brevis (green) at different glucose concentrations (0.042, 0.085, 0.17, 0.20, 0.33, 0.40, 0.50, 0.68, 0.83, 1.20, 1.67, 2.50, 3.33, and 5 mM) at constant cell number (4.8 × 109 cells). Three independent measurements were performed to calculate mean potential change rate values. The blue arrow in the diagram indicates a particular glucose concentration (1.67 mM), which was exemplarily chosen to compare calibration curves of metabolic responses of the three microorganisms by cell number variations.

Quantitative differential monitoring of the metabolic activity of Corynebacterium glutamicum cultures utilizing a light-addressable potentiometric sensor system

Applying biosensors for evaluation of the extracellular acidification of microorganisms in various biotechnological fermentation processes is on demand. An early stage detection of disturbances in the production line would avoid costly interventions related to metabolically inactive microorganisms. Furthermore, the determination of the number of living cells through cell plating procedure after cultivations is known as time- and material-consuming. In this work, a differential light-addressable potentiometric sensor (LAPS) system was developed to monitor the metabolic activity of Corynebacterium glutamicum (C. glutamicum ATCC13032) as typical microorganism in fermentation processes. In this context, the number of living cells in suspensions was directly determined utilizing the read-out principle of the LAPS system. The planar sensor surface of the LAPS design allows to fixate 3D-printed multi-chamber structures, which enables differential measurements. In this way, undesirable external influences such as pH variations of the medium and sensor signal drift can be compensated.

DC arc suppression in the improved multichamber structure

In order to apply the multichamber structure to DC lines, it’s necessary to know the principle of arc quenching and the arc development process in the multichamber structure. Through analyzing the quenching characteristics of DC arc and establishing the 2-D geometric model of multichamber structure based on the magnetohydrodynamics theory in COMSOL Multiphysics simulation platform, this paper reveals and explains the principle of arc quenching in the multichamber structure. The simulation result shows that the strong self-expanding airflow which caused by the instantaneous temperature rise in the chambers can cut off the arc channel and block the energy supply of the arc. Then the Impulse-DC arc quenching test is carried out to verify the arcing performance of the improved multichamber structure. The arc is finally extinguished at 1.5ms, which manifests that the improved device can effectively suppress DC arc development.

Ethanol-Induced Cervical Sympathetic Ganglion Block Applications for Promoting Canine Inferior Alveolar Nerve Regeneration Using an Artificial Nerve.

Polyglycolic acid collagen (PGA-C) tubes are bio-absorbable nerve tubes filled with collagen of multi-chamber structure, which consist of thin collagen films. Favorable clinical outcomes have been achieved when using these tubes for the treatment of damaged inferior alveolar nerve (IAN). A critical factor for the successful nerve regeneration using PGA-C tubes is blood supply to the surrounding tissue. Cervical sympathetic ganglion block (CSGB) creates a sympathetic blockade in the head and neck region thus increasing blood flow in the area. To ensure an adequate effect, the blockade must be administered with local anesthetics one to two times a day for several consecutive weeks; this poses a challenge when creating animal models for investigating this technique. To address this limitation, we developed an ethanol-induced CSGB in a canine model of long-term increase in blood flow in the orofacial region. We examined whether IAN regeneration via PGA-C tube implantation can be enhanced by this model. Fourteen Beagles were each implanted with a PGA-C tube across a 10-mm gap in the left IAN. The IAN is located within the mandibular canal surrounded by bone, therefore we chose piezoelectric surgery, consisting of ultrasonic waves, for bone processing, in order to minimize the risk of nerve and vessel injury. A good surgical outcome was obtained with this approach. A week after surgery, seven of these dogs were subjected to left CSGB by injection of ethanol. Ethanol-induced CSGB resulted in improved nerve regeneration, suggesting that the increased blood flow effectively promotes nerve regeneration in IAN defects. This canine model can contribute to further research on the long-term effects of CSGB.

Analysis on the heat-recuperable hybrid cycle for micro swing engine with a non-isometric multi-chamber structure

With low efficiency and insufficient power, the conventional micro swing engine has not been available for portable power source. Therefore a novel hybrid thermodynamic cycle with heat recuperation ability, which is suitable for the micro swing engine, is proposed to overcome the above defects, whose thermodynamic characteristics are investigated in details, indicating a great improvement for the engine performance. Firstly, the micro swing engine is modified to be a three-arm engine with a non-isometric multi-chamber structure. Driven by the hybrid cycle, the engine body and a specially designed spiral recuperator work together successfully in theory. Thus, the entire efficiency is increased by heat recovery from hot exhaust and restriction of structural heat leakage. In consideration of flow leakage effect, simulation models of the steady working process of the engine in hybrid cycle are established. Numerical results reveal that, thermal performance of the hybrid cycle has an obvious advantage over the single thermal cycle. Moreover, the hybrid cycle is composed of two single four-stroke cycles and two two-stroke cycles. The two adjacent cylinders, between whom the flow leakage happens, are with different cycles, and hence distinct thermal performances. Finally, with the application of this heat recovery process, the efficiency of the four-stroke cylinders is improved relatively by 45.31% and the total engine efficiency is increased by 14.09%. Effectiveness and practicability of the hybrid cycle with heat recuperation are demonstrated theoretically, which is of great significance for the progress in micro heat engine field.

New Layouts of Fiber Reinforcements to Enable Full Finger Motion Assist with Pneumatic Multi-Chamber Elastomer Actuators

Fiber-reinforced fluid-driven elastomer actuators have enabled the production of simple, low-cost and safe hand rehabilitation devices. However, so far, the actuators support only finger flexion-extension, and little has been reported on abduction-adduction, which is essential for manipulation tasks and grasping larger objects. The technical design difficulty of realizing abduction-adduction lies in the suppression of interference effects between the metacarpophalangeal (MCP) joint’s two orthogonal motion axes, caused by the necessary multi-chamber actuator structure and its reinforcements, under strong spatial constraints. This problem has not been solved yet, regardless of research efforts on designing various actuator structures. In this study, our goal was to enable flexion of all three finger joints and abduction-adduction of the MCP joint, while minimizing the interference and realizing required ranges of motion. For this, we propose two new types of fiber reinforcements (separate single loops and two-directional hitching) and their combination to direct a multi-chamber structure’s expansion and strengthen its force output into the wanted directions. The reinforcements’ effects on actuator response were evaluated by attaching prototypes to a dummy finger and measuring its range of motion and related joint torques and forces. Results showed that the single loops provided length extension, while the hitching constrained it from the bottom at the centerline and strengthened flexion. When combined, they could be used to adjust the amount of length extension and flexion along the actuator, without detrimentally affecting the flexion or abduction-adduction functions. In conclusion, the two new reinforcement types have the potential of being a major design factor for fitting the actuators’ response for different users’ finger kinematics.

The influence of spatial distribution on add-on therapy of designed Ca-Alg/CS MEMs system

To improve the efficacy and reduce the systemic toxicity of the diabetes mellitus, herewith, we developed a novel microparticles-embedded microcapsules (MEMs) system, synthesized from calcium alginate/chitosan (Ca-Alg/CS), by emulsion gelation using a high voltage electrostatic droplet generator. In our study, we selected two antidiabetic drugs insulin (INS) and metformin (MET) as model drugs to investigate different spatial distribution appropriate of MEMs system. Characterization based on particle size and morphology, encapsulation efficiency and drug loading, as well as drug delivery properties were carried out on the MEMs system. Typical multi-chamber structure was shown by SEM and the optical spectra. The average diameters of microparticles and Ca-Alg/CS MEMs were 2100 nm and 410 μm, respectively. Insulin and MET were embedded into MEMs via electrostatic reaction according to FT-IR spectra. Moreover, drug loading and encapsulation efficiency of INS were higher than that of MET in this system when drugs were loaded alone or together. More importantly, this system has potential for orderly drug release and well sustained release when MET in the inner and INS in the outer space could be applied as a combination therapy for diabetes. The obtained in vivo experimental data on diabetes rats has shown that the designed MEMs system resulted in a higher hypoglycemic effect within add-on therapy.