isothermal heating
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Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1151
Author(s):  
Kamalalayam Rajan Sreejith ◽  
Muhammad Umer ◽  
Larissa Dirr ◽  
Benjamin Bailly ◽  
Patrice Guillon ◽  
...  

This paper reports the design, development, and testing of a novel, yet simple and low-cost portable device for the rapid detection of SARS-CoV-2. The device performs loop mediated isothermal amplification (LAMP) and provides visually distinguishable images of the fluorescence emitted from the samples. The device utilises an aluminium block embedded with a cartridge heater for isothermal heating of the sample and a single-board computer and camera for fluorescence detection. The device demonstrates promising results within 20 min using clinically relevant starting concentrations of the synthetic template. Time-to-signal data for this device are considerably lower compared to standard quantitative Polymerase Chain Reaction(qPCR) machine (~10–20 min vs. >38 min) for 1 × 102 starting template copy number. The device in its fully optimized and characterized state can potentially be used as simple to operate, rapid, sensitive, and inexpensive platform for population screening as well as point-of-need severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) detection and patient management.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4411
Author(s):  
Grzegorz Łukaszewicz ◽  
Krzysztof Wasiak ◽  
Emilia K. Skołek ◽  
Ryszard Diduszko ◽  
Wiesław A. Świątnicki

Intermediate annealing treatment (IAT) is a new process that accelerates the bainitic transformation in steels. This stimulation is crucial, especially in the prolonged production of nanobainitic steels. Among other recognised methods, it seems to be an effective and economical process. However, there are very few research works in this area. The objective of this study was to collate microstructural changes caused by IAT with differences in the kinetics of the subsequent bainitic transformation in the X37CrMoV5-1 tool steel. Differential dilatometry, LM and SEM microscopic observations, EDS and XRD analysis, and computer simulations were used to investigate the effect of IAT on the kinetics of bainitic transformation. The study has revealed that introducing an additional isothermal heating stage immediately after austenitising significantly affects the kinetics of bainitic transformation—it can accelerate or suppress it. The type and strength of the effect depends on the concentration, distribution, and morphology of the precipitations that occurred during IAT.


Author(s):  
Kamalalayam Rajan Sreejith ◽  
Muhammad Umer ◽  
Narshone Soda ◽  
Surasak Kasetsirikul ◽  
Muhammad Shiddiky ◽  
...  

This paper reports the design, development, and testing of a novel, yet simple and low-cost portable device for the rapid detection of SARS-CoV-2. The device performs loop mediated isothermal amplification (LAMP) and provides visually distinguishable images of the fluorescence emitted from the samples. The device utilises an aluminium block embedded with a cartridge heater for isothermal heating of the sample and a single-board computer and camera for fluorescence detection. The device demonstrates promising results within 20 minutes using clinically relevant starting concentrations of the synthetic template. Time-to-signal data for this device are considerably lower compared to standard qPCR machine (~10-20 minutes vs >38 minutes) for 1×105 starting template copy number. The device in its fully optimized and characterized state can potentially be used as simple to operate, rapid, sensitive, and inexpensive platform for population screening as well as point-of-need SARS-CoV-2 detection and patient management.


Author(s):  
Obehi Dibua ◽  
Chee S. Foong ◽  
Michael Cullinan

Abstract Nanoparticles are being used in Additive Manufacturing to improve on the minimum feature sizes that the processes are able to achieve. In order to accurately control this process, it is important to understand the underlying characteristics that define the sintering of nanoparticles. This is done by modelling the process. A nanoparticle simulation has been introduced to model the sintering between the nanoparticles in a powder bed. These simulations make use of Phase Field Modelling to track the diffusion between the particles in the system. However, the current state of the simulations only consider the sintering of single layers of powder beds subject to isothermal heating. For the simulation to be able to simulate an actual Additive Manufacturing process where a 3D part is built, the model has to consider the characteristics of multiple layers of nanoparticles in beds undergoing sintering. Additionally, during Additive Manufacturing processes like Selective Laser Sintering, where the bed is not undergoing an even temperature heating, a nanoparticle sintering simulation for this process must be able to account for these temperature changes. This paper presents advancements in simulating nanoparticle sintering to be able to model the sintering behavior between multiple layers of nanoparticles as well as the effects of a temperature gradient on the sintering of nanoparticles.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Saqib ◽  
Ilyas Khan ◽  
Sharidan Shafie ◽  
Ahmad Qushairi Mohamad

AbstractThe colloidal suspension of nanometer-sized particles of Fe3O4 in traditional base fluids is referred to as Ferro-nanofluids. These fluids have many technological applications such as cell separation, drug delivery, magnetic resonance imaging, heat dissipation, damping, and dynamic sealing. Due to the massive applications of Ferro-nanofluids, the main objective of this study is to consider the MHD flow of water-based Ferro-nanofluid in the presence of thermal radiation, heat generation, and nanoparticle shape effect. The Caputo-Fabrizio time-fractional Brinkman type fluid model is utilized to demonstrate the proposed flow phenomenon with oscillating and ramped heating boundary conditions. The Laplace transform method is used to solve the model for both ramped and isothermal heating for exact solutions. The ramped and isothermal solutions are simultaneously plotted in the various figures to study the influence of pertinent flow parameters. The results revealed that the fractional parameter has a great impact on both temperature and velocity fields. In the case of ramped heating, both temperature and velocity fields decreasing with increasing fractional parameter. However, in the isothermal case, this trend reverses near the plate and gradually, ramped, and isothermal heating became alike away from the plate for the fractional parameter. Finally, the solutions for temperature and velocity fields are reduced to classical form and validated with already published results.


2021 ◽  
Vol 10 ◽  
pp. 56-64
Author(s):  
R. I. Gulyaeva ◽  
◽  
S. V. Sergeeva ◽  
S. A. Petrova ◽  
L. Yu. Udoeva ◽  
...  

Processes of calciothermal reduction of metals from iron (FeTa2O6) and manganese (MnTa2O6) tantalates as well as tantalum oxide (Ta2O5) were studied in this work. According to the results of thermodynamic analysis performed in the temperature range 373 – 2773 К, the interaction of FeTa2O6 and MnTa2O6 with calcium proceeds with complete reduction of metals. By the calculation and comparison of the lgK equilibrium constants for the reactions of alumino- and calciothermal reduction of iron and manganese tantalates were showed the thermodynamic advantage of using metallic calcium as a reducing agent. Experimental investigations of calciothermal reduction on samples of synthesized oxides were carried out by the method of combined thermogravimetry and differential thermal analysis in the mode of non-isothermal heating to 1473 K in an argon flow. X-ray powder diffraction was used to determine the phase composition of the initial samples and interaction products. It was shown that the calciothermal reduction of metals from the synthesized manganese tantalate proceeds actively at temperatures above 1196 K, while iron tantalate and tantalum oxide with the appearance of molten calcium. Tantalum and its solid solutions with iron or manganese, corresponding to the structural type Ta7Fe6, were included in the main metal components of the products of the interaction of FeTa2O6 and MnTa2O6 with calcium.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5133 ◽  
Author(s):  
Lingen Chen ◽  
Chenqi Tang ◽  
Huijun Feng ◽  
Yanlin Ge

One or more isothermal heating process was introduced to modify single and regenerative Brayton cycles by some scholars, which effectively improved the thermal efficiency and significantly reduced the emissions. To analyze and optimize the performance of this type of Brayton cycle, a regenerative modified Brayton cycle with an isothermal heating process is established in this paper based on finite time thermodynamics. The isothermal pressure drop ratio is variable. The irreversibilities of the compressor, turbine and all heat exchangers are considered in the cycle, and the heat reservoirs are variable-temperature ones. The function expressions of four performance indexes; that is, dimensionless power output, thermal efficiency, dimensionless power density and dimensionless ecological function are obtained. With the dimensionless power density as the optimization objective, the heat conductance distributions among all heat exchangers and the thermal capacitance rate matching among the working fluid and heat reservoir are optimized. Based on the NSGA-II algorithm, the cycle’s double-, triple- and quadruple-objective optimization are conducted with the total pressure ratio and the heat conductance distributions among heat exchangers as design variables. The optimal value is chosen from the Pareto frontier by applying the LINMAP, TOPSIS and Shannon entropy methods. The results show that when the pressure ratio in the compressor is less than 12.0, it is beneficial to add the regenerator to improve the cycle performance; when the pressure ratio is greater than 12.0, adding the regenerator will reduce the cycle performance. For single-objective optimization, the four performance indexes could be maximized under the optimal pressure ratios, respectively. When the pressure ratio is greater than 9.2, the cycle is simplified to a closed irreversible simple modified Brayton cycle with one isothermal heating process and coupled to variable-temperature heat reservoirs. Therefore, when the regenerator is used, the range of pressure ratio is limited, and a suitable pressure ratio should be selected. The triple objective (dimensionless power output, dimensionless power density and dimensionless ecological function) optimization’ deviation index gained by LINMAP or TOPSIS method is the smallest. The optimization results gained in this paper could offer some new pointers for the regenerative Brayton cycles’ optimal designs.


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