The main goal of the present paper is to study the energy dissipation characteristic as the influence of parameters in the event of ship collisions. The review is conducted on accident case between Roll on-Roll off (R...
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The main goal of the present paper is to study the energy dissipation characteristic as the influence of parameters in the event of ship collisions. The review is conducted on accident case between Roll on-Roll off (Ro-Ro) Marisa Nusantara with Reefer Qi Hang at Sunda Strait, Indonesia May 3rd, 2014, as reference. It was later modeled and analyzed by nonlinear simulations finite element (FE) method was presented to be used as a reference to get the verified model. This collaboration study is considered as a good reference because it used real accident damage to compare the numerical results. The result in collision energy from the virtual simulation was later verified with the calculation result of the empirical formula. In the extended study, the collision region and material model are selected as influenced parameters to design collision scenarios. The characteristic of collision energy from these scenarios will be discussed. In the same section, the damage pattern is observed and reviewed to find the relation between several parameters to calculation results. It was shown that the influence of region and location of target points contributed significantly to energy dissipation. In contrast, the key finding in material properties is that when Young’s modulus between materials was the same and the difference of yield strength of materials was not significant, then other material properties contributed to the result.
Textile industries generally consume a significant amount of electricity in their business operations, hence, efforts to reduce their consumption is necessary. This study assesses the energy consumption and energy sav...
Textile industries generally consume a significant amount of electricity in their business operations, hence, efforts to reduce their consumption is necessary. This study assesses the energy consumption and energy saving opportunities in a textile company in Indonesia. A structured energy audit using Define-Measure-Analyze-Improve-Control (DMAIC) was implemented in the Spinning department. The evaluation indicates that 80% of the Specific Energy Consumption (SEC) are dominated by the factory air conditioner and chiller which is corresponding to 515 kWh/kg and 219 kWh/kg respectively. The Coefficient of Performance (COP) of the plant cooling system is 7.41 which conforms to the COP national standard. Further energy-saving opportunities include closing the door and other gateways of the air, replacing the refrigerant material from Freon R-134 to Musicool Mc-134, and installing inverter on mist nozzle motor, evaporator pump, condenser pump, and cooling tower.
Every year, at least 100 million tons of solid waste globally comes from packaging waste, in which partly created by inefficient packaging. Multiple box arrangement or bin packing solution directly addresses this prob...
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A self-standing,flexible and lithium dendrite growth-suppressing composite gel polymer electrolyte membrane was designed for the use of room-temperature lithium ion *** multi-functional composite semi-interpenetrating...
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A self-standing,flexible and lithium dendrite growth-suppressing composite gel polymer electrolyte membrane was designed for the use of room-temperature lithium ion *** multi-functional composite semi-interpenetrating polymer network(referred to as“Cs-IPN”)electrolyte membrane was fabricated by combining a UV-cured ethoxylated trimethylolpropane triacrylate(ETPTA)macromer with alumina nanoparticles in the presence of liquid electrolyte and thermoplastic linear poly(ethylene oxide)(PEO).The polymer electrolyte membrane exhibits a semi-interpenetrating polymer network structure and a higher room temperature ionic conductivity,which impart the electrolyte with a significant cycling(120 mAh g^(-1)after 200 cycles)and a remarkable rate(137 mAh g^(-1)at 0.1℃,130 mAh g^(-1)at 0.5℃,119 mAh g^(-1)at 1℃ and 100 mAh g^(-1)at 2℃)performance in Li/LiFePO4 *** importantly,the polymer electrolyte possesses superior ability to inhibit the growth of lithium dendrites,which makes it promising for next generation lithium ion batteries.
Many exact coherent states (ECS) arising in wall-bounded shear flows have an asymptotic structure at extreme Reynolds number Re in which the effective Reynolds number governing the streak and roll dynamics is O(1). Co...
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This study aimed to determine the printability of the AlCoCrCu 0.5 FeNi high-entropy alloy produced by laser powder bed fusion (LPBF) and evaluate the degree of densification, microstructural evolution, and mechanical...
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Stroke often results in hemiplegia, which greatly affects the walking ability of the patients. We propose a multi-functional portable ankle exoskeleton for use in preventing foot-drops, assisting propulsion, and stabi...
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ISBN:
(数字)9781728159072
ISBN:
(纸本)9781728159089
Stroke often results in hemiplegia, which greatly affects the walking ability of the patients. We propose a multi-functional portable ankle exoskeleton for use in preventing foot-drops, assisting propulsion, and stabilizing inversion/eversion during walking to help gait rehabilitation of stroke patients. The portable ankle exoskeleton was fabricated by 3D printing a soft/rigid hybrid structure. The device was able to prevent foot-drop and assist propulsion with a bi-directional cable-driven actuation system. It also showed a capability of stabilizing inversion/eversion motions using a counter-electromotive force of two small, lightweight gear motors. The device was controlled by a microcontroller based on real-time feedback from one inertial measurement unit and a customized force sensitive resistor. The device is fully untethered with all the components integrated on-board, with a total weight of less than 1 kg. Five healthy subjects performed over-ground walking tests with the proposed ankle exoskeleton for three different walking situations (normal walking, walking with simulated foot-drop, and walking on an uneven terrain) and three walking conditions (without the exoskeleton, with the exoskeleton powered off, and with the exoskeleton powered on). From the test results, we confirmed the feasibility of the proposed ankle exoskeleton for foot-drop prevention, propulsion assistance, and inversion/eversion stabilization. The ankle exoskeleton showed a potential for wearable gait rehabilitation for stroke patients with high mobility and portability.
In this study, AA2519 alloy was initially processed by multi axial forging (MAF) at room and cryogenic temperatures. Subsequently, the microstructure and the mechanical behavior of the processed samples under quasi-st...
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In this study, AA2519 alloy was initially processed by multi axial forging (MAF) at room and cryogenic temperatures. Subsequently, the microstructure and the mechanical behavior of the processed samples under quasi-static loading were investigated to determine the influence of cryogenic forging on alloys’ subgrains dimensions, grain boundaries interactions, strength, ductility and toughness. In addition, the failure mechanisms at the tensile rupture surfaces were characterized using scanning electron micro-scope (SEM). The results show significant improvements in the strength, ductility and toughness of the alloy as a result of the cryogenic MAF process. The formation of nanoscale crystallite microstructure, heavily deformed grains with high density of grain boundaries and second phase breakage to finer particles were characterized as the main reasons for the increase in the mechanical properties of the cryogenic forged samples. The cryogenic processing of the alloy resulted in the formation of an ultrafine grained material with tensile strength and toughness that are ~41% and ~80% higher respectively after 2 cycles MAF when compared with the materials processed at ambient temperature. The fractography analysis on the tested materials shows a substantial ductility improvement in the cryoforged (CF) samples when compared to the room temperature forged (RTF) samples which is in alignment with their stress-strain profiles. However, extended forging at higher cycles than 2 cycles led only to increase in strength at the expense of ductility for both the CF and RTF samples.
Soft robotics aims at creating systems with improved performance of movement and adaptability in unknown, challenging, environments and with higher level of safety during interactions with humans. This Roadmap on Soft...
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For robots to exhibit a high level of intelligence in the real world, they must be able to assess objects for which they have no prior knowledge. Therefore, it is crucial for robots to perceive object affordances by r...
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ISBN:
(数字)9781728173955
ISBN:
(纸本)9781728173962
For robots to exhibit a high level of intelligence in the real world, they must be able to assess objects for which they have no prior knowledge. Therefore, it is crucial for robots to perceive object affordances by reasoning about physical interactions with the object. In this paper, we propose a novel method to provide robots with an ability to imagine object affordances using physical simulations. The class of chair is chosen here as an initial category of objects to illustrate a more general paradigm. In our method, the robot "imagines" the affordance of an arbitrarily oriented object as a chair by simulating a physical sitting interaction between an articulated human body and the object. This object affordance reasoning is used as a cue for object classification (chair vs non-chair). Moreover, if an object is classified as a chair, the affordance reasoning can also predict the upright pose of the object which allows the sitting interaction to take place. We call this type of poses the functional pose. We demonstrate our method in chair classification on synthetic 3D CAD models. Although our method uses only 30 models for training, it outperforms appearance-based deep learning methods, which require a large amount of training data, when the upright orientation is not assumed to be known a priori. In addition, we showcase that the functional pose predictions of our method align well with human judgments on both synthetic models and real objects scanned by a depth camera.
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