Article
Environmental Sciences
Arvind Kumar Singh, Abhishek Saxena, Nitin Agarwal
Summary: The study aims to investigate the thermal performance of solar air heaters using different absorber plates and configurations. The experiments were conducted in the summer conditions of Moradabad City, India, and four different models of solar air heaters were developed. The results showed that Model-4 performed the best with an average exhaust temperature of about 46 degrees C after sunset. The modified system showed higher efficiency compared to conventional systems, making it suitable for moderate-temperature applications such as agricultural drying and space heating.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Thermodynamics
Sreedevi Paramparambath, Muni Raj Maurya, Mohammad Talal Houkan, John-John Cabibihan, Kishor Kumar Sadasivuni
Summary: Paraffin wax, a commonly used phase-change material, has limitations in energy storage applications due to its low thermal conductivity. In this study, graphite and graphite-hydrogel were added to enhance the thermal conductivity and heat release properties of paraffin wax. The synthesized wax-graphite-hydrogel composite demonstrated significantly improved thermal conductivity and the potential to decrease the working temperature of semiconductor devices.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Energy & Fuels
Kin Yuen Leong, Syafawati Hasbi, K. Z. Ku Ahmad, Norazrina Mat Jali, Hwai Chyuan Ong, M. F. Md Din
Summary: This study investigates the effect of different weights of multi-walled carbon nanotubes and various surfactants on the thermal conductivity and thermal performance of paraffin wax. The results show that adding 0.06 wt% of multi-walled carbon nanotubes without surfactant can significantly enhance the thermal conductivity of paraffin wax.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Thermodynamics
Imtiaz Ali Laghari, A. K. Pandey, M. Samykano, Belqasem Aljafari, K. Kadirgama, Kamal Sharma, V. V. Tyagi
Summary: Solar energy is a plentiful renewable energy source that can meet the growing demand. Thermal energy storage using phase change material (PCM) is a promising technique, but PCM's low thermal conductivity limits its use. Enhancing thermal conductivity with nanomaterials, such as graphene nanoparticles, is a solution to overcome this issue.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Energy & Fuels
R. Harish
Summary: This study numerically investigates the thermo-magnetic turbulent convection induced melting of nanoenriched paraffin wax dispersed with hybrid magnetic nanoparticle pairs. The dispersion of hybrid nanoparticle pairs enhances the melting fraction and average Nusselt number of paraffin wax. The natural convection induced melting generates quadruplet thermal plume patterns.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Energy & Fuels
Svetlana N. Gorbacheva, Veronika V. Makarova, Sergey O. Ilyin
Summary: This study considered using hydrophobic nano-sized silicon dioxide as a stabilizer to obtain stable dispersions of graphite in paraffin wax, and investigated the joint influence of silica and graphite fillers on the ability of paraffin wax to accumulate and conduct heat.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Construction & Building Technology
C. Gutierrez-Blandon, A. A. Cuadri, A. Tenorio-Alfonso, P. Partal, F. J. Navarro
Summary: This paper analyzes the thermomechanical properties, heat storage characteristics and compatibility of bitumen blends with a paraffin wax as phase change material. The results show partial compatibility between the blends, and the development of a multiphasic microstructure. Despite the partial compatibility, the blends exhibit a high degree of crystallinity, which makes them suitable for applications requiring thermal energy storage.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Energy & Fuels
Jalal M. Jalil, Salih M. Salih
Summary: This paper analyzes the performance of double glazed windows filled with paraffin wax in Baghdad, Iraq, aiming to evaluate the improvement in thermal comfort. The results show that the temperature of the double glazed window is significantly reduced compared to the single glass window on different floors, with reductions of 8, 6, and 5 degrees Celsius.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Energy & Fuels
R. Bharathiraja, T. Ramkumar, M. Selvakumar
Summary: The purpose of this research is to improve the thermal energy storage properties of paraffin wax by adding nanoparticles, such as Multi-Walled Carbon Nanotubes (MWCNTs) and nano SiO2. The results showed that dispersing nanoparticles in paraffin wax can significantly enhance the thermal conductivity of the composite and lower the melting and solidification temperatures of the wax.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Nanoscience & Nanotechnology
Feilong Shao, Lingling Wang, Rongrong Luo, Wei Yu, Huaqing Xie
Summary: In this study, a shape-stable hybrid emulsion gel (EGel/GO) was developed through Pickering emulsion polymerization, which combines sodium acetate trihydrate (SAT) and paraffin wax (PW). The polymer dual-phase cross-linking in EGel/GO enhances the material's shape stability, slows the loss of crystalline water in hydrates, and reduces supercooling. Addition of graphene oxide (GO) increases the optical absorption properties of EGel/GO-0.5, resulting in a high photothermal conversion efficiency of 89.1%. Furthermore, EGel/GO has high latent heat and no leakage or phase separation, making it an ideal choice for effective utilization of solar energy and building energy storage.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Thermodynamics
Shehab A. Mansour, Ahmed A. Atwa, Elsayed M. Farag, Ragab A. Elsad
Summary: This study fabricated and characterized PCM nanocomposites based on paraffin wax (PW) loaded by anatase titania (TiO2) nanoparticles (NPs). The addition of TiO2 NPs improved the thermal performance of the PCM, as evidenced by higher melting point, latent heat of fusion, and latent heat rate compared to a pure PW sample. The thermal stability of the nanocomposites varied non-monotonically with TiO2 NP concentrations, with an improvement observed up to a concentration of 0.25 mass% and rapid degradation at higher concentrations.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
M. W. Boomstra, M. W. J. van Asseldonk, B. J. Geurts, V. M. Nazarychev, A. V. Lyulin
Summary: Paraffin waxes are phase change materials with potential applications. However, their low thermal conductivity hampers their use in heat batteries. This study investigates the effects of polydispersity and branching on the thermal conductivity of paraffin waxes using molecular dynamics simulations, providing insights for designing hybrid materials with improved properties.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
A. S. Sathishkumar, K. Arun Balasubramanian, T. Ramkumar
Summary: The research article investigates the impact of hybrid composite powders of multi-wall carbon nanotube (MWCNT) and nano-boron nitride (NBN) on the thermal properties of paraffin wax for thermal storage applications. Various phase change material (PCM) samples were prepared and evaluated for physical and thermal properties. The results show that the addition of MWCNT and NBN enhances the thermal conductivity of paraffin wax, but also affects its degradation and solidification temperatures. Increasing the mass % of MWCNT and NBN lowers the melting point but increases the solidification temperature of paraffin wax. This research highlights the significant improvement in thermal properties of paraffin wax with the inclusion of composite powders (MWCNT and NBN).
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Energy & Fuels
Liang Wang, Yifei Wang
Summary: By using numerical calculation and simulation to study the effects of different fin thickness, fin space, and the number of ducts on the heat storage and release process of paraffin, it is found that optimized parameters can improve the performance of the paraffin regenerator, showing the significant role of heat transfer between air and paraffin. The best combination regenerator can maintain indoor heating for eight hours with its melting degree and released heat.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Energy & Fuels
Sedi Helsper, Matthew W. Liberatore
Summary: Increasing oil production from cold environments has led to flow assurance issues caused by wax deposition and hydrate formation. This study investigates the high-pressure flow properties of waxy oils and finds that wax concentration has a larger effect on wax appearance temperature than pressure. Understanding waxy oil rheology under methane-saturated, high-pressure conditions is crucial for addressing flow assurance challenges in cold environments.
Article
Multidisciplinary Sciences
Guo-Hua Feng, Kuan-Yi Lee
ROYAL SOCIETY OPEN SCIENCE
(2017)
Article
Engineering, Electrical & Electronic
Guo-Hua Feng, Sheng-You Hou
SENSORS AND ACTUATORS A-PHYSICAL
(2018)
Article
Engineering, Electrical & Electronic
Guo-Hua Feng, Wei-Ming Tseng
IEEE SENSORS JOURNAL
(2018)
Article
Chemistry, Analytical
Guo-Hua Feng, Hong-Yu Liu
Article
Chemistry, Analytical
Guo-Hua Feng, Hua-Jin Liu
Article
Instruments & Instrumentation
Guo-Hua Feng, Cheng-Yen Chiang
SMART MATERIALS AND STRUCTURES
(2020)
Article
Chemistry, Multidisciplinary
Guo-Hua Feng, Gui-Rong Lai
Summary: This paper presents an effective signal processing scheme for hand gesture recognition with a high accuracy rate of 99.8%. Through the study of different hand gestures and motions, a new recognition method is proposed, along with the continuous short-period analysis technique for determining the starting time of gestures. The fusion of short-time Fourier transform spectrogram and image processing techniques proves to be successful for hand gesture recognition.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Guo-Hua Feng, Pin-Cheng Su
Summary: This study introduces a piezoelectric airflow sensor based on barium titanate film, which has a compact size suitable for wearable devices. An algorithm is proposed to determine the sensor's performance and monitor important breath parameters.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Chemistry, Analytical
Guo-Hua Feng, Wen-Sheng Chen
Summary: In this study, a piezoelectric micromachined ultrasonic transducer (PMUT) is integrated with a microliter-sized volume-tunable Helmholtz resonator. Experimental results show that the sound pressure level (SPL) and operation bandwidth can be effectively tuned. A modified Helmholtz resonator model is proposed to provide insight into the operation and estimation for optimal design and fabrication.
Article
Engineering, Electrical & Electronic
Chung-Hao Huang, Guo-Hua Feng
Summary: This paper presents a micromachined ultrasonic microphone that is fabricated using a bottom-up approach. The microphone consists of a 4μm-thick titanium foil substrate, a hydrothermally grown piezoelectric lead zirconate titanate film, and a sensing cantilever array. The microphone demonstrates a sensitivity of -60 dBV Pa-1 at 21 kHz and an operation bandwidth of 5-55 kHz.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2023)
Article
Engineering, Mechanical
Shang-Hsien Liu, Yung-Chou Kao, Guo-Hua Feng
Summary: This study developed a three-axis vibrational haptic wearable device (RCWS) utilizing Linear Resonant Actuators (LRAs) to simulate grinding vibrations. The implementation of RCWS is described in detail. By recording the normal force during manual grinding with a load cell and converting it into a series of PWM commands, the LRA on the RCWS was controlled in open-loop mode using these PWM commands. Three methods were tested for force-to-PWM conversion, two of which showed a linear correlation (>0.7) with raw data. In the correlation between PWM commands and generated acceleration, all three methods exhibited a high linearity of at least 0.85. This wearable RCWS offers a promising approach for users to experience the machining force from the versatile and critical remote machining process with a finger vibratory sensation.
Article
Engineering, Electrical & Electronic
Hung-Yu Yeh, Guo-Hua Feng
Summary: This letter presents a novel wearable breath monitoring device created by micromachined thin-film technology. The device possesses precise respiratory rate sensing, breathing air temperature, and heating functions, which are all realized on one piece of barium titanate (BTO) film with different layout designs.
IEEE SENSORS LETTERS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Guo-Hua Feng, Hong-Yu Li
2019 20TH INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS & EUROSENSORS XXXIII (TRANSDUCERS & EUROSENSORS XXXIII)
(2019)
Proceedings Paper
Engineering, Electrical & Electronic
Guo-Hua Feng, Cheng-Yen Chiang
2019 20TH INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS & EUROSENSORS XXXIII (TRANSDUCERS & EUROSENSORS XXXIII)
(2019)
Proceedings Paper
Engineering, Electrical & Electronic
Guo-Hua Feng, Shao-Rong Ye, Ming-En Wei
2017 19TH INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS (TRANSDUCERS)
(2017)
Article
Engineering, Electrical & Electronic
Bruno Galizia, Patrick Fiorenza, Corrado Bongiorno, Bela Pecz, Zsolt Fogarassy, Emanuela Schiliro, Filippo Giannazzo, Fabrizio Roccaforte, Raffaella Lo Nigro
Summary: This study demonstrates the growth of oriented AlN thin films on 4H-SiC substrates using PE-ALD technique, and investigates the impact of NH3 plasma pulsing on the microstructure and orientation degree of the AlN layers. The structural characterization reveals different polymorphic structures depending on the NH3 plasma pulsing time, and electrical nanoscopic characterization shows a correlation between the AlN crystalline phases and the insulating properties.
MICROELECTRONIC ENGINEERING
(2024)
Article
Engineering, Electrical & Electronic
Theo Levert, Alter Zakhtser, Julien Duval, Chloe Raguenez, Stephane Verdier, Delphine Le Cunff, Jean-Herve Tortai, Bernard Pelissier
Summary: In this study, the robustness of optical constants and optical band gap determination of three different materials is compared using a combination of spectroscopic ellipsometry and energy loss signal of X-ray photoelectron spectroscopy. The hybridization of these two techniques provides a new robust method for determining the band gap of the studied materials and other optical properties over a wide energy range.
MICROELECTRONIC ENGINEERING
(2024)
