Greenhouse gases emitted from the excessive use of fossil fuels are threatening the environment, and thus alternative resources like biomass are being considered as a replacement. Biomass with high ...moisture content is better treated by hydrothermal carbonization method than any other process to generate biofuel. Research on this method on a lab scale has progressed recently. However, due to the complex reaction mechanisms and operational barriers, more improvements are required to make it a commercial technology. This paper aims to review the development of hydrothermal carbonization with a focus on the practical aspects of the process. Many references have been reviewed critically to provide a well-structured source for improving this process. After providing information about the biomass structure and general knowledge of hydrothermal carbonization, the challenges faced in attempts to improve the process have been identified as lack of valid kinetic and heat transfer models and insufficient data on continuous and large-scale reactors. Useful and practical suggestions have been presented to tackle all these challenges.
•Hydrothermal carbonization (HTC) should be industrialized to valorize wet biomass.•Effect of operational parameters should be studied in both lab and industrial-scale.•Kinetic and energy modeling are more challenging due to unknown chemical reactions.•The approaches to address the gaps have been clearly explained.•Combining HTC with other processes has been proposed.
•A comprehensive survey of electromagnetic and piezoelectric MPGs is presented.•This paper will help to develop a new configuration of EMPG and PMPG in future.•This paper will help to identify the ...application fields of different MPGs.•This paper will allow developing hybrid MPGs with optimum output.
The area of micro power generation has developed significantly over the last two decades in the field of microelectromechanical systems, self-powered wireless sensor nodes, and mobile platforms. Battery is the main power source of such systems but it has some limitations which include finite life time, periodic replacement, and environmental pollutions. Therefore, electrochemical battery system is not a suitable fit for wireless self-powered electronic industry. Energy harvesting through renewable energy such as mechanical vibration can be an attractive alternative solution to replace or widen the lifespan of the traditional battery system. A good number of researches have been conducted on vibration based micro power generation to support the microelectromechanical systems. Electromagnetic, piezoelectric, and electrostatic transducers are used to convert kinetic energy (i.e., mechanical vibration) into electrical energy. A comprehensive literature review has been presented on vibration based micro power generation using two most common transducer mechanisms: electromagnetic and piezoelectric transduction systems.
In this paper, a manual dispenser printing-based fabrication technique has been developed to synthesize a flexible thermoelectric generator (FTEG). Fabricated FTEGs, printed on polyester fiber ...clothe, convert the thermal energy from the human body into electrical energy using the Seebeck effect. Two flexible prototypes (prototype A and prototype B) were fabricated using a manual dispenser printing technique with n-type (0.98Bi,0.02Sb)2(0.9Te,0.1Se)3 and p-type (0.25Bi,0.75Sb)2(0.95Te,0.05Se)3 thermoelectric (TE) materials. The fabricated prototypes consisted of 12 pairs of n-type and p-type legs connected by silver conductive threads. The experimental investigations were conducted to determine the characteristics and the electrical outputs of the fabricated prototypes. The open circuit voltage and power output of prototype A and prototype B were 22.1 mV and 2.21 nW, and 23.9 mV and 3.107 nW, respectively, at 22.5 °C temperature difference. The fabricated prototypes were also tested on the human body at different body conditions and were found to be very flexible, twistable, and durable with the substrate as well as conforming well to the human body.
•Flexible thermoelectric generators were developed by a dispenser printing method.•Theoretical analysis & experimental tests were performed on two prototypes.•The prototypes were very flexible, twistable, and durable with the substrate.•The voltage output is relatively higher than FTEGs reported in the literature.
A relatively novel concept in plate heat exchangers is Pillow Plate Heat Exchanger (PPHX), which has demonstrated promising potential in heat transfer efficiency. However, the concept leads to a ...higher pressure drop compared to controversial models, and still, the effects of its geometrical parameters and operational conditions on efficiency are not clarified, comprehensively. In this study, a PPHX is designed and simulated to clarify the major reasons for pressure drop and entropy generation. In this regard, a 3D model of PPHX by considering conjugate heat transfer is developed and numerically investigated by using ANSYS Fluent. The calculations are accomplished for a wide range of
Re
numbers (
10
3
to
2.1
×
10
4
) consisting of both laminar and turbulent flow regimes. The results are presented in terms of frictional coefficient, Colburn factor, heat transfer coefficient, entropy generation and second law efficiency for different welding spot diameters. It is observed that while increasing the diameter causes a higher pressure drop, it lowers heat transfer and irreversibility. Up to 12% variation in the efficiency is obtained for considered diameters. Meanwhile, although entropy generation due to temperature variation plays a major role in total entropy, entropy generation due to pressure drop has shown an exponential increment as the
Re
number increases.
In this paper, we present a recent survey on robotic grippers. In many cases, modern grippers outperform their older counterparts which are now stronger, more repeatable, and faster. Technological ...advancements have also attributed to the development of gripping various objects. This includes soft fabrics, microelectromechanical systems, and synthetic sheets. In addition, newer materials are being used to improve functionality of grippers, which include piezoelectric, shape memory alloys, smart fluids, carbon fiber, and many more. This paper covers the very first robotic gripper to the newest developments in grasping methods. Unlike other survey papers, we focus on the applications of robotic grippers in industrial, medical, for fragile objects and soft fabrics grippers. We report on new advancements on grasping mechanisms and discuss their behavior for different purposes. Finally, we present the future trends of grippers in terms of flexibility and performance and their vital applications in emerging areas of robotic surgery, industrial assembly, space exploration, and micromanipulation. These advancements will provide a future outlook on the new trends in robotic grippers.
This research focuses on the thermoelectric (TE) material by incorporating SiC nanoparticles to investigate nanocomposite-based materials’ characteristics and the TE system’s overall performance. In ...this paper, a comprehensive analysis has been studied on the TE materials and SiC nanoparticles’ morphology to present the shape, size, and distribution by considering scanning electron microscope (SEM) and X-ray powder diffraction (XRD) technologies. The result indicates that adding SiC nanoparticles with TE materials considerably improved the system’s performance by decreasing the thermal conductivity (30.7%) and increasing the Seebeck coefficient (7.5%). Furthermore, a numerical investigation has been conducted on the performance analysis of the rectangular and trapezoidal-shaped TE legs. It is reported that the rectangular-shaped TE unit generates more power output around 3 µW and 2 µW compared to the constant and non-constant volume TE leg geometry, respectively, at a load current of 0.04 mA under a temperature difference of 100 °C. The rectangular-shaped TE unit outperforms the trapezoidal-shaped TE unit. However, the rectangular-shaped TE leg requires comparatively high TE materials (34.5%), increasing the investment by 33.9%.
Accurate estimation of a battery’s capacity is critical for determining its state of health (SOH) and retirement, as well as to ensure its reliable operation. In this paper, a dual filter ...architecture using the Kalman filter (KF) and the novel sliding innovation filter (SIF) was implemented to estimate the capacity and state of charge (SOC) of a lithium-ion battery. NASA’s Prognostic Center of Excellence (PCOE) B005 battery data set was selected for this experiment based on its wide use in academia and industry. This dataset contains cycling data of a 2 Ah lithium-ion battery until its capacity was measured at 1.3 Ah or less. The dual polarity equivalent circuit model (DP-ECM) was selected for modeling. The model parameter values were estimated using the least squares (LS) algorithm. Under normal operating conditions, both the dual-KF and dual-SIF performed similarly in terms of estimation accuracy. However, an uncertainty case was considered where the filters were subjected to rapid changing dynamics by cutting the data by 300 cycles. In this case, the battery capacity root-mean-square error (RMSE) for the dual-KF and the proposed dual-SIF were 0.1233 and 0.0675, respectively. Under rapidly changing dynamics and faulty conditions, the dual-SIF shows better convergence and robustness to disturbances.
Due to their nonlinear behavior and the harsh environments to which batteries are subjected, they require a robust battery monitoring system (BMS) that accurately estimates their state of charge ...(SOC) and state of health (SOH) to ensure each battery’s safe operation. In this study, the interacting multiple model (IMM) algorithm is implemented in conjunction with an estimation strategy to accurately estimate the SOH and SOC of batteries under cycling conditions. The IMM allows for an adaptive mechanism to account for the decaying battery capacity while the battery is in use. The proposed strategy utilizes the sliding innovation filter (SIF) to estimate the SOC while the IMM serves as a process to update the parameter values of the battery model as the battery ages. The performance of the proposed strategy was tested using the well-known B005 battery dataset available at NASA’s Prognostic Data Repository. This strategy partitions the experimental dataset to build a database of different SOH models of the battery, allowing the IMM to select the most accurate representation of the battery’s current conditions while in operation, thus determining the current SOH of the battery. Future work in the area of battery retirement is also considered.
Solid-state thermoelectric refrigeration and heat pump systems can be integrated with battery packs in electric vehicles (EV) and hybrid electric vehicles (HEV) for effective thermal management in ...both hot and cold environments. Operating modes can be switched by changing the polarity of the input voltage to the thermoelectric system. In this paper, a new design of a battery pack is proposed which includes an acrylic battery container, copper battery holders, liquid cooling medium, and battery cells. This battery pack is integrated with a battery thermal management system (BTMS) which includes thermoelectric cooling (TEC) in combination with liquid and air circulations. The aim of the BTMS is to handle heat generation during operation of the battery pack. Heat, generated by the battery pack, is transported to the cold end of the TEC and then dissipated to the surrounding environment by a heatsink. Fundamental design optimization is carried out on a single cell first. System performance is then validated in the battery pack experiments. For the 40 V test, the proposed system reached approximately 20 °C lower when compared with only liquid cooling. In the 30 V power supply test, the battery pack temperature did not exceed 30 °C in a period of 5000 s. Furthermore, the battery pack temperature was under 60 °C at 3000 s during a continuous discharge condition with a 50 V input, which is considered an extreme condition for battery operation.
•This paper purpose a battery pack design for advanced BTMS performance validation.•This paper validates the design parameters of a thermoelectric cooling based BTMS.•This paper shows the excellent cooling effect of thermoelectric coolers in BTMS.•This paper reveals the great potential of TEC module using in EV/HEV applications.
In the present study, the laminar flow and heat transfer of water jet impingement enhanced with nano-encapsulated phase change material (NEPCM) slurry on a hot plate is analytically investigated for ...the first time. A similarity solution approach is applied to momentum and energy equations in order to determine the flow velocity and heat transfer fields. The effect of different physical parameters such as jet velocity, Reynolds number, jet inlet temperature, and the NEPCM concentration on the cooling performance of the impinging jet are investigated. The volume fraction of NEPCM particles plays an essential role in the flow and heat transfer fields. The results show that NEPCM slurry can significantly enhance the cooling performance of the system as it improves the latent heat storage capacity of the liquid jet. However, the maximum cooling performance of the system is achieved under an optimum NEPCM concentration (15%). A further increase in NEPCM volume fraction has an unfavorable effect due to increasing the viscosity and reducing the conductivity simultaneously. The effect of adding nano-metal particles on the heat transfer performance is also investigated and compared with NEPCM slurry. NEPCM slurry shows a better result in its maximum performance. Compared with the water jet, adding nano and NEPCM particles would overall enhance the system’s thermal performance by 16% and 7%, respectively.
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