scholarly journals Numerical Investigation of Design and Operating Parameters of Thermal Gradient Continuous-Flow PCR Microreactor Using One Heater

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 919
Author(s):  
Usama Perwez ◽  
Imran Aziz ◽  
Faisal Ahmed ◽  
Mohsin Raza Khan

To respond to the dire need for miniaturization and process simplification of continuous-flow PCR (CF-PCR) device, this paper represents design and operation guide of a novel metal alloy assisted hybrid microdevice (polydimethylsiloxane (PDMS) and glass) for CF-PCR employing one heater. In this research, the specific objectives are to determine whether one heater chip design will be flexible enough when the size of DNA base pair is varied and to investigate whether one heater CF-PCR device will be able to resolve the longstanding problem of thermal crosstalk. Furthermore, the parametric study is performed to determine which of the fourteen parameters have the greatest impact on the performance of one heater CF-PCR device. The main objective of this parametric study is to distinguish between the parameters that are either critical to the chip performance or can be freely specified. It is found that substrate thickness, flow rate, channel spacing, aspect ratio, channel pass length and external heat transfer coefficient are the most limiting parameters that can either improve or deteriorate the chip’s thermal performance. Overall, the impact of design and operating parameters are observed to be least on thermocycling profile at low Reynolds number (≤0.37 Re). However, in addition to the primary metric advantages of CF-PCR, one heater chip design helps in minimizing the thermal crosstalk effects by a factor of 4 in comparison to dual heater PCR while still maintaining a critical criteria of chip flexibility in terms of handling various sizes of DNA fragments. Hence, the proposed scheme paves the way for low-cost point-of-care diagnostics, system integration, and device miniaturization, realizing a portable microfluidic device applicable for on-site and direct field uses.

1991 ◽  
Vol 113 (1) ◽  
pp. 40-50 ◽  
Author(s):  
R. H. Tindell

The impact of computational fluid dynamics (CFD) methods on the development of advanced aerospace vehicles is growing stronger year by year. Design engineers are now becoming familiar with CFD tools and are developing productive methods and techniques for their applications. This paper presents and discusses applications of CFD methods used at Grumman to design and predict the performance of propulsion system elements such as inlets and nozzles. The paper demonstrates techniques for applying various CFD codes and shows several interesting and unique results. A novel application of a supersonic Euler analysis of an inlet approach flow field, to clarify a wind tunnel-to-flight data conflict, is presented. In another example, calculations and measurements of low-speed inlet performance at angle of attack are compared. This is highlighted by employing a simplistic and low-cost computational model. More complex inlet flow phenomena at high angles of attack, calculated using an approach that combines a panel method with a Navier-Stokes (N-S) code, is also reviewed. The inlet fluid mechanics picture is rounded out by describing an N-S calculation and a comparison with test data of an offset diffuser having massively separated flow on one wall. Finally, the propulsion integration picture is completed by a discussion of the results of nozzle-afterbody calculations, using both a complete aircraft simulation in a N-S code, and a more economical calculation using an equivalent body of revolution technique.


Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 207 ◽  
Author(s):  
Petros Petrounias ◽  
Aikaterini Rogkala ◽  
Panagiota Giannakopoulou ◽  
Basilios Tsikouras ◽  
Paraskevi Lampropoulou ◽  
...  

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials, as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this study, in order to examine the remediation, in lab scale, of the drainage waste water of Agios Philippos mine, an experimental electrically continuous flow-driven forced device was constructed, enriching the research gap relative to this type of remediation approach. Through this experimental device, the use of certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat, and biochar) was studied. Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the new 7-day experimental electrically continuous flow-driven forced device with certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 was achieved. Moreover, with use of the experimental device, the removal of toxic load was achieved, and more specifically the concentration of Fe was decreased from 6149 to 1300 ppb, Cu from 8847 to 35 ppb, and Zn from 285,458 to 50,000 ppb.


Author(s):  
Petros Petrounias ◽  
Aikaterini Rogkala ◽  
Panagiota P. Giannakopoulou ◽  
Basilios Tsikouras ◽  
Paraskevi Lampropoulou ◽  
...  

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this way, the value of mineral raw materials can be prolonged for as long as possible, waste generation and exploitation of natural resources are minimized and resources are kept as far as possible within the existing economy. In this study, an electrically continuous flow driven forced device proposed and demonstrated for the remediation of waste water in lab-scale by using certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat and biochar). Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the proposed 7-day experimental electrically continuous flow driven forced device with the certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 as well as significant removal of Fe, Cu and Zn was achieved.


Author(s):  
R. H. Tindell

The impact of computational fluid dynamics (CFD) methods on the development of advanced aerospace vehicles is growing stronger year by year. Design engineers are now becoming familiar with CFD tools and are developing productive methods and techniques for their applications. This paper presents and discusses applications of CFD methods used at Grumman to design and predict the performance of propulsion system elements such as inlets and nozzles. The paper demonstrates techniques for applying various CFD codes and shows several interesting and unique results. A novel application of a supersonic Euler analysis of an inlet approach flow field, to clarify a wind tunnel-to-flight data conflict, is presented. In another example, calculations and measurements of low-speed inlet performance at angle of attack are compared. This is highlighted by employing a simplistic and low-cost computational model. More complex inlet flow phenomena at high angles of attack, calculated using an approach that combines a panel method with a Navier-Stokes (N-S) code, is also reviewed. The inlet fluid mechanics picture is rounded out by describing an N-S calculation and a comparison with test data of an offset diffuser having massively separated flow on one wall. Finally, the propulsion integration picture is completed by a discussion of the results of nozzle-afterbody calculations, using both a complete aircraft simulation in a N-S code, and a more economical calculation using an equivalent body of revolution technique.


2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.


Author(s):  
J.R. Caradus ◽  
D.A. Clark

The New Zealand dairy industry recognises that to remain competitive it must continue to invest in research and development. Outcomes from research have ensured year-round provision of low-cost feed from pasture while improving productivity. Some of these advances, discussed in this paper, include the use of white clover in pasture, understanding the impacts of grass endophyte, improved dairy cow nutrition, the use of alternative forage species and nitrogen fertiliser to improve productivity, demonstration of the impact of days-in-milk on profitability, and the use of feed budgeting and appropriate pasture management. Keywords: dairy, profitability, research and development


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