Reliable separation of circulating tumor cells from blood cells is crucial for early cancer diagnosis and prognosis. Many conventional microfluidic platforms take advantage of the size difference between particles for their separation, which renders them impractical for sorting overlapping-sized cells. To address this concern, a hybrid inertial-dielectrophoretic microfluidic chip is proposed in this work for continuous and single-stage separation of lung cancer cell line A549 cells from white blood cells of overlapping size. The working mechanism of the proposed spiral microchannel embedded with planar interdigitated electrodes is validated against the experimental results. A numerical investigation is carried out over a range of flow conditions and electric field intensity to determine the separation efficiency and migration characteristics of the cell mixture. The results demonstrate the unique capability of the proposed microchannel to achieve high-throughput separation of cells at low applied voltages in both vertical and lateral directions. A significant lateral separation distance between the CTCs and the WBCs has been achieved, which allows for high-resolution and effective separation of cells. The separation resolution can be controlled by adjusting the strength of the applied electric field. Furthermore, the results demonstrate that the lateral separation distance is maximum at a voltage termed the critical voltage, which increases with the increase in the flow rate. The proposed microchannel and the developed technique can provide valuable insight into the development of a tunable and robust medical device for effective and high-throughput separation of cancer cells from the WBCs. 

Isolation and detection of circulating tumor cells (CTCs) hold significant importance for the early diagnosis of cancer and the assessment of therapeutic strategies. However, the scarcity of CTCs among peripheral blood cells presents a major challenge to their detection. Additionally, a similar size range between CTCs and white blood cells (WBCs) makes conventional microfluidic platforms inadequate for the isolation of CTCs. To overcome these challenges, in this study, a novel inertial-dielectrophoretic microfluidic channel for size-independent, single-stage separation of CTCs from WBCs has been presented. The proposed device utilizes a spiral microchannel embedded with interdigitated electrodes. A numerical model is developed and validated to investigate the influence of various parameters related to the channel design, fluid flow, and electrode configuration. It was found that optimal separation of CTCs could be obtained at a relatively low voltage, termed the critical voltage. Furthermore, at the critical voltage of 7.5 V, the hybrid microchannel is demonstrated to be capable of separating CTCs from different WBC subtypes including granulocytes, monocytes, T-, and B-lymphocytes. The unique capabilities of the hybrid spiral microchannel allow for this size-independent isolation of CTCs from a mixture of WBCs. Overall, the proposed technique can be readily utilized for continuous and high-throughput separation of cancer cells. 

Circulating tumor cells (CTCs) are shed from primary tumors, circulate in the bloodstream and are capable of initiating metastasis at distant anatomical sites. The detection and molecular characterization of CTCs are pivotal for early-stage cancer diagnosis and prognosis. Recently, microfluidic technology has achieved significant progress in the separation of cells from complex and heterogeneous mixtures for many biomedical applications. Conventional microfluidic platforms exploit the difference in size between the particles to achieve separation, which makes them ineffective for sorting overlapping-sized CTCs. To address this issue, we propose a method using a spiral channel for label-free, and high throughput separation of CTCs coupling Dielectrophoresis (DEP) with inertial microfluidics. A numerical model has been developed to investigate the separation effectiveness of the device over a range of electrical voltage and flow rates. The presented channel is shown to effectively isolate similar-sized CTCs from the white blood cells (WBCs) in a single-stage separation process. Subsequently, optimum working parameters to enhance separation efficiency have been proposed. The hybrid microfluidic device can provide valuable insight into the development of a robust, inexpensive, and efficient platform for cell separation with reduced analysis time for future cancer research and treatment. 

Circulating tumor cells (CTCs) are proven to be a primary indicator of vital diagnostic and clinical information for early-stage cancer detection. Effective separation of CTCs from blood is crucial for genetic characterization of CTCs, drug development, and improvement of cell cycle-targeted therapies. Many conventional microfluidic platforms isolate CTCs based on their size difference from other blood cells which renders them impractical for sorting overlapping-sized cells. To address this issue, we propose a method using a zigzag channel for continuous, label-free, and high throughput separation of CTCs coupling Dielectrophoresis (DEP) with inertial microfluidics. This hybrid channel exhibits enhanced similar sized cell separation resolution and single-step retrieval of viable CTCs by combining inertial lift force, DEP force, and alternating curvature induced Dean force. In our numerical investigation, separation of MDA-231 CTCs from identical sized WBCs has been achieved at a high Reynolds number of 125. Furthermore, the working parameters such as Reynolds number, Voltage, and electrode configuration have been optimized for enhancing the separation efficiency. The proposed design can provide valuable insight into the development of a versatile, efficient, inexpensive, and novel platform with reduced analysis time for cancer diagnosis and prognosis.

Deterministic lateral displacement (DLD) is a microfluidic method for the continuous separation of particles based on their size. There is growing interest in using DLD for harvesting circulating tumor cells from blood for further assays due to its low cost and robustness. While DLD is a powerful tool and development of high-throughput DLD separation devices holds great promise in cancer diagnostics and therapeutics, much of the experimental data analysis in DLD research still relies on error-prone and time-consuming manual processes. There is a strong need to automate data analysis in microfluidic devices to reduce human errors and the manual processing time. In this work, a reliable particle detection method is developed as the basis for the DLD separation analysis. Python and its available packages are used for machine vision techniques, along with existing identification methods and machine learning models. Three machine learning techniques are implemented and compared in the determination of the DLD separation mode. The program provides a significant reduction in video analysis time in DLD separation, achieving an overall particle detection accuracy of 97.86% with an average computation time of 25.274 s. 

The thermodynamic performance of a two-stage vapor compression cascade refrigeration system using hydrocarbon refrigerants is studied extensively in this study. The selection of hydrocarbon refrigerants for the cascade refrigeration system is conducted based on the molecular weight, freezing point, vaporization, density, global warming potential and ozone depletion potential. In the lower temperature circuit, Trans-2-butane (T2BUTENE) is utilized while Toluene (toluene), Cyclopentane (CYCLOPEN) and Cis-2-butane (C2BUTENE) are used on the higher temperature circuit. The performance of the system is evaluated considering three major operating temperature such as evaporator temperature, condensation temperature of lower temperature circuit (LTC), and condensation temperature of higher temperature circuit (HTC). Furthermore, comparisons between the presented work and the previous established work are conducted to show the improved performance of cascade refrigeration utilizing the hydrocarbon refrigerants. The results from the simulations suggest that highest COP and exergy efficiency is achieved when Trans-2-butane is employed in lower temperature circuit while Toluene is implemented on the higher temperature circuit. The results also suggest that the highest exergy destruction occurs at the condenser and the lowest can occur either at the lower circuit expansion valve or the evaporator for different refrigerant pairs. In addition, utilizing hydrocarbon refrigerants on cascade refrigeration systems can achieve a minimum 7.21 % higher COP than the recently employed refrigerants in previously established published works. 

This work presents a detailed thermodynamic analysis of a triple cascade vapor refrigeration system (TCRS) utilizing hydrocarbon refrigerants for ultra-low temperature application. Different hydrocarbon refrigerants pairs are used in different circuits (High temperature circuit HTC, Mid temperature circuit MTC, and Low temperature circuit LTC) to obtain the most suitable refrigerant combination by mathematical modeling of the system. The design and operating parameters considered in this study include (1) evaporator temperature (2) LTC condensation temperature (3) MTC condensation temperature. A thermodynamic analysis consisting of energy and exergy analysis were employed in terms of operating conditions to obtain COP, total compressor work, exergy efficiency, total exergy destruction, mass flow rate and discharge temperatures of compressors. Furthermore, an analysis on component exergy destruction was conducted to show the possibilities of improvement of TCRS utilizing the hydrocarbon refrigerants. The results suggest that at different evaporator temperatures different hydrocarbon refrigerants on TCRS give higher COP and exergy efficiency. The highest COP and exergy efficiency at −100 °C evaporator temperature was calculated to be 0.5931 and 54.446 %, respectively. This study also suggests that hydrocarbon refrigerants can be used in ultra-low temperature applications without compromising the thermodynamic performance of the refrigeration system. 

With a population of 165 million, Bangladesh is undergoing rapid industrialization and urban development, and is well on track to move out from the group of least developed countries by 2024. This results in a significant increase in the urban energy needs and the amount of generated waste. Most of the municipal solid waste in Bangladesh is currently deposited in landfills, thereby contaminating nearby cultivable soils. It is desirable to have a system that recovers energy from the municipal solid waste in order to satisfy the increasing energy needs, while simultaneously addressing the land scarcity and pollution issues. This paper proposes using incineration to recover energy from municipal solid waste to produce electricity in the urban areas of Dhaka and Chattogram. A detailed technical analysis involving energy, exergy, exergoeconomic, and emission is presented. The power plants in these two cities show potential capacities of 169 MW and 83 MW respectively, with exergoeconomic factors of 61 %. The results indicate energy and exergy efficiencies of 32 % and 27 %, respectively, and a production cost in the range of 53.9–56.7 USD/MWh which is comparable to the production cost from the current power plants in Bangladesh. The proposed plants also result in a reduction in the greenhouse emissions and exhibit ecological efficiencies of over 87 %. 

In many remote localities, one of the underlying reasons for not receiving life-saving vaccines is the lack of electricity to store the vaccines in the required refrigerated conditions. Solar Photovoltaic (PV) refrigerators have been considered as a viable and green solution to store the vaccines in remote localities having no access to electricity. In this paper, a detailed methodology has been presented for the performance evaluation of a solar PV powered vaccine refrigerator for remote locations. Thermal modelling with hourly cooling load calculations and refrigeration cycle simulations were carried out. The performance parameters for three environment-friendly refrigerants: R152a, R1234yf, and R1234ze(E) has been compared against the commonly used R134a for two remote, off-grid locations in Bangladesh and South Sudan. The energy systems comprising of solar PV panels and batteries to run the refrigerator were modelled in HOMER software for techno-economic optimizations. For both the locations, R152a was found to be the best performing refrigerant exhibiting higher COP (2%−5.29%) as compared to the other refrigerants throughout the year, while R1234ze(E) exhibited COPs on par with R134a, and R1234yf had the least performance. Techno-economic analysis showed an energy system providing electricity to the refrigerator with R152a also had lower levelized cost of electricity (0.48%−2.54%) than the systems having other refrigerants in these locations. 

The Hyperloop promises to revolutionize the transport infrastructure of the 21st century by reducing travel time and allowing people to reach transonic speed on land. It carries with it the hope of a sustainable transportation system during an era of global energy crisis. Overall passenger safety in a high-speed pod necessitates a reliable braking system. This paper introduces the possibility of utilizing aerodynamic drag in the Hyperloop, anticipated to operate at high Mach and low Reynolds flow regime, to attenuate the speed of the pod. Numerical analysis was conducted to investigate the effect of incorporating an aerodynamic brake at different pod velocities (100, 135, and 150 m/s) and deployment angles (30°, 45°, 60°, and 90°). A detailed comparison between the proposed aerodynamic braking system (AeBS) and existing braking systems for the Hyperloop has been presented in this paper. The results demonstrate an increase in drag value of the pod by 3.4 times using a single 0.15 m2 brake plate. When the brake plate was fully deployed at a pod velocity in excess of 112 m/s, the aerodynamic drag-based braking systems was shown to be more effective than the contemporary eddy current braking system.