Aqueous redox flow batteries (RFBs) are promising alternatives for large-scale energy storage. However, new organic redox-active molecules with good chemical stability and high solubility are still desired for high-pe...
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Legged motion has significant advantages over traditional locomotion techniques. Research and development on it have been constantly improving over the last couple of decades. Though there are numerous techniques in d...
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Practitioners often rely on compute-intensive domain randomization to ensure reinforcement learning policies trained in simulation can robustly transfer to the real world. Due to unmodeled nonlinearities in the real s...
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Permanent hip joint damage caused by calcification, aging, or accidents requires replacement using artificial hip joint replacement surgery. Among the biomaterial applications, the Total Hip Replacement (THR) method i...
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Permanent hip joint damage caused by calcification, aging, or accidents requires replacement using artificial hip joint replacement surgery. Among the biomaterial applications, the Total Hip Replacement (THR) method is the most successful. Many types of artificial hip joints are available in the commercial market. Various types of material and design can be selected to suit the needs of the patients. One of which is the design with fenestration type on the hip stem. In terms of materials, Titanium and stainless steel are the ones commonly used in hip joint replacement. In this paper, the effects of fenestration hip stem on mechanical behavior have been studied using the finite element analysis. Several hip designs, i.e., the hip joint without fenestration, hip joint with fenestration slot, hip joint with fenestration big loop, and hip joint with fenestration multi-loop, were considered in this study. All models were applied using Autodesk inventor model. Static structural analysis was performed using ANSYS to conclude at the best fenestration. Results showed that for Ti-6Al-4V material, design with many loop fenestration has the lowest stress than others, with the result obtained is 495.46 MPa. However, the artificial hip stem with slot fenestration has the smallest deformation with the least difference in value compared to other designs with distortion 0.54808 mm. In addition, the design that produced the higher stress von-Misses was big loop fenestration 526,28 MPa. In conclusion, it was found that all four designs indicated lesser stress values than the yield strength.
Air pollution and scarcity of fuel oil are the result of the high consumption rate of conventional motorized vehicles. Innovation of science and technology is needed in overcoming this pollution. Transitioning the use...
Air pollution and scarcity of fuel oil are the result of the high consumption rate of conventional motorized vehicles. Innovation of science and technology is needed in overcoming this pollution. Transitioning the use of vehicles, especially conventional oil-fueled cars to hybrid electric cars, is a innovation to overcome this. An important aspect of hybrid engine performance is related to changes in temperature variations that occur. Writing the article aims to examine the performance of hybrid cars in various temperature variations. Temperature varieties influence the current, voltage, and SOC of the battery which influences the motor progress (on/off). The impact of temperature is dissected to restrict the working scope of the vehicle to accomplish eco-friendly execution alongside longer battery life. The mistake between the normal and determined SOC esteems is tiny and accordingly gives the genuine mileage esteem. At lower temperatures, the mileage is lower and at higher temperatures it is high contrasted with the room temperature esteems, along these lines checking the hypothesis of the impact of temperature on the response pace of the battery cells.
Lignocellulosic biomass contains more than 60% of cellulose consisting of glucose and fructose that can be converted into synthetic fuel, called Dimethylfuran (DMF). DFM contains high energy density and research octan...
Lignocellulosic biomass contains more than 60% of cellulose consisting of glucose and fructose that can be converted into synthetic fuel, called Dimethylfuran (DMF). DFM contains high energy density and research octane number, and low water solubility that is more appropriate than ethanol in terms of fuel. Production will start with the dehydration process to form 5-Hydroxymethylfural which will be converted to DMF in the following process. The purpose of this study was to evaluate the optimum conditions for the acid hydrolysis or dehydration conversion of glucose and fructose to 5-hydroxymethyfurfural. Response surface methodology and central composite design were used to facilitate the optimization of process variables. The HCI content ranged from 1.65 to 4.95% w/w, and the reaction time ranged from 30 to 40 minutes at a constant temperature of 140 °C. The results showed that the highest conversions for both glucose and fructose to HMF of 67 and 76 % could be achieved from 3.3 % w/w of HCl concentration and the reaction time of 35 min.
Online control design using a high-fidelity, full-order model for a bipedal robot can be challenging due to the size of the state space of the model. A commonly adopted solution to overcome this challenge is to approx...
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ISBN:
(数字)9781728173955
ISBN:
(纸本)9781728173962
Online control design using a high-fidelity, full-order model for a bipedal robot can be challenging due to the size of the state space of the model. A commonly adopted solution to overcome this challenge is to approximate the fullorder model (anchor) with a simplified, reduced-order model (template), while performing control synthesis. Unfortunately it is challenging to make formal guarantees about the safety of an anchor model using a controller designed in an online fashion using a template model. To address this problem, this paper proposes a method to generate safety-preserving controllers for anchor models by performing reachability analysis on template models by relying on functions that bound the difference between the two models. This paper describes how this reachable set can be incorporated into a Model Predictive Control framework to select controllers that result in safe walking on the anchor model in an online fashion. The method is illustrated on a 5-link RABBIT model, and is shown to allow the robot to walk safely while utilizing controllers designed in an online fashion.
Many questions are still open regarding the physical mechanisms behind the magnetic switching in Gd-Fe-Co alloys by single optical pulses. Phenomenological models suggest a femtosecond scale exchange relaxation betwee...
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Many questions are still open regarding the physical mechanisms behind the magnetic switching in Gd-Fe-Co alloys by single optical pulses. Phenomenological models suggest a femtosecond scale exchange relaxation between sublattice magnetization as the driving mechanism for switching. The recent observation of thermally induced switching in Gd-Fe-Co by using both several picosecond optical laser pulse as well as electric current pulses has questioned this previous understanding. This has raised the question of whether or not the same switching mechanics are acting at the femtosecond and picosecond scales. In this work, we aim at filling this gap in the understanding of the switching mechanisms behind thermal single-pulse switching. To that end, we have studied experimentally thermal single-pulse switching in Gd-Fe-Co alloys, for a wide range of system parameters, such as composition, laser power, and pulse duration. We provide a quantitative description of the switching dynamics using atomistic spin dynamics methods with excellent agreement between the model and our experiments across a wide range of parameters and timescales, ranging from femtoseconds to picoseconds. Furthermore, we find distinct element-specific damping parameters as a key ingredient for switching with long picosecond pulses and argue that switching with pulse durations as long as 15 ps is possible due to a low damping constant of Gd. Our findings can be easily extended to speed up dynamics in other contexts where ferrimagnetic Gd-Fe-Co alloys have been already demonstrated to show fast and energy-efficient processes, e.g., domain-wall motion in a track and spin-orbit torque switching in spintronics devices.
To produce halal, safe, and affordable food collagen are factors that need to be resolved in food processing industry. Collagen was made from milkfish scales and B. megaterium TR-10. Freeze drying method has been arou...
To produce halal, safe, and affordable food collagen are factors that need to be resolved in food processing industry. Collagen was made from milkfish scales and B. megaterium TR-10. Freeze drying method has been around for a long time and usually use in food processing, including collagen production. Freeze drying techniques need in this separation of protein and water as a solvent due addition of acetone and NaCl so that the protein has not to denaturation due to processing above 50ᵒC. Computational method to simulate heat and mass transfer freeze drying in the collagen formation at -60ᵒC with a pressure less than 10 Pa to obtain optimal efficiency. When compared to conventional dryers, hybrid freeze dryers excel in several key areas: drying efficiency, energy efficiency, moisture removal procedure, product quality, and nutrient or bioactive ingredient preservation. The simulation using a foam mat with variation 1mm, 3mm, and 5mm. Changing product into a foam to expand the surface area and mass transfer increase thus drying process take a short time. This simulation begins with designing use Ansys R21 and the next process is numerical calculations to analyze heat and mass transfer in freeze drying process to obtain optimal efficiency result. The optimal value is obtained because effectiveness heat and mass transfer process when the collagen converted into foam causing surface largen with thinnest layers. Drying time with hybrid technique is between 1/4 to 1/7 times faster compared non-foam drying.
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