Article
Engineering, Environmental
Junghoon Mok, Wonjung Choi, Yongwon Seo
Summary: This study investigated the thermodynamic stability and kinetic growth behavior of HFC-152a hydrate, finding that HFC-152a hydrate has a higher hydration capacity in the presence of NaCl. The results suggest that HFC-152a may be a superior candidate for the HBD process.
Article
Thermodynamics
Quan Zhong, Minting Wu, Huan Zhao, Huajie Li, Youlin Zhang, Jun Shen, Yujie Huang
Summary: In this study, vapor-liquid equilibrium properties were measured for fluoroethane (R161) + 1,1-difluoroethane (R152a) binary system and difluoromethane (R32) + R161 + R152a ternary system using a static analytical apparatus. The measured data were regressed using PR-vdW and PR-NRTL-MHV2 models, with a pressure-based objective function used for correlation. The maximum average absolute relative deviation in pressure calculated by the models were 0.75% for R161 + R152a and 0.77% for R32 + R161 + R152a using PR-vdW model, and 0.68% for R161 + R152a and 0.62% for R32 + R161 + R152a using PR-NRTL-MHV2 model. No azeotropic behavior was observed in the binary and ternary systems.
JOURNAL OF CHEMICAL THERMODYNAMICS
(2023)
Article
Chemistry, Analytical
Nicholas B. Tiscione, Timothy P. Rohrig
Summary: DFE, commonly used as a propellant in air dusters, can be abused as an inhalant leading to fatal outcomes and central nervous system depression. Its effects may impair human performance and impact traffic safety.
JOURNAL OF ANALYTICAL TOXICOLOGY
(2021)
Article
Thermodynamics
Yu Liao, Yuande Dai, Chaoping Xu
Summary: This study presents the experimental data on the vapor-liquid equilibrium of the binary mixture R152a/R1234ze(E) and correlates the experimental data using a computational model, showing a high degree of agreement between the model and experimental results.
JOURNAL OF CHEMICAL THERMODYNAMICS
(2022)
Article
Chemistry, Physical
Swayam Kesari, Brahmananda Chakraborty, A. K. Rajarajan, Antara Vaidyanathan, Rekha Rao
Summary: Compounds with polymorphism at ambient conditions exhibit interesting structural transitions under different thermodynamic conditions. Gd2Si2O7 is a silicate that shows polymorphism at ambient conditions, with significant structural changes at high pressures leading to different phases.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Geochemistry & Geophysics
Juan Chen, Heping Li, Yi Yuan, Mengxue Zhang, Shuhang Shuai, Jingjing Wan
Summary: Variations in the Raman spectra of pyrite were studied under different temperatures and pressures. The results showed that temperature increase led to a decrease in frequencies and the transformation from pyrite to hematite. The interaction of pressure and temperature also affected the Raman modes.
Article
Thermodynamics
Shuzhou Peng, Erqi Wang, Zhen Yang, Yuanyuan Duan
Summary: In this study, the vapor-liquid equilibrium (VLE) of the R152a + R1234ze(E) and R152a + R1243zf systems was measured and analyzed using a mathematical model. The results showed that the R152a + R1234ze(E) system is zeotropic while the R152a + R1243zf system is azeotropic.
FLUID PHASE EQUILIBRIA
(2022)
Article
Multidisciplinary Sciences
Madalina Oprica, Miruna Iota, Monica Daescu, Szilard N. Fejer, Catalin Negrila, Mihaela Baibarac
Summary: The study reports the photodegradation process of atorvastatin calcium (ATC) depending on different factors, including excipients, phosphate buffer, and hydrolysis reaction. The novelty of the work lies in monitoring ATC photodegradation through photoluminescence (PL). Exposure of ATC to UV light in solid state induces photo-oxygenation reactions leading to compounds with a higher share of C=O bonds compared to the original ATC.
SCIENTIFIC REPORTS
(2021)
Article
Energy & Fuels
Shui-Tao Zhang, Lin-Lin Wang
Summary: This paper establishes a theoretical framework to investigate the evolution of fluid pressure in hydrate-bearing sediments during the methane hydrate decomposition process. The model considers the effect of pore volume change and capillary effect, and examines the pressure built-up mechanisms. The study reveals that the density contrast dominates the pore pressure accumulation, leading to potential fracturing of the sediment.
Article
Thermodynamics
Marek Krolikowski, Mikolaj Wieckowski, Mojgan Ebrahiminejadhasanabadi, Wayne Michael Nelson, Paramespri Naidoo, Deresh Ramjugernath, Urszula Domanska
Summary: This study continues the research on the applicability of two new synthesized ionic liquids (ILs) in absorbing carbon dioxide. Experimental vapor-liquid equilibrium data for IL + CO2 systems were obtained, and new solubility data for the ILs were presented. The results show that these new ILs have higher CO2 solubility and can be modeled using mathematical equations.
FLUID PHASE EQUILIBRIA
(2022)
Article
Chemistry, Physical
Asheesh Kumar, Hari Prakash Veluswamy, Sanat Kumar, Rajnish Kumar, Praveen Linga
Summary: Clathrate hydrate-based sustainable technologies, such as solidified natural gas (SNG) technology, show great potential for storing natural gas. Experiments on mixed hydrates in a seawater environment reveal the promotional effect of seawater on hydrate formation and suggest the economic feasibility of using natural seawater to enhance SNG technology.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Spectroscopy
K. Beton, P. Wysocki, B. Brozek-Pluska
Summary: The study focused on the effects of statins on colon cancer cells, showing their inhibitory effects on cancer cell growth. Through comparison with normal cells, the influence of statins on the biochemical composition of cancerous cells was confirmed.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Biochemistry & Molecular Biology
Hiromi Kimura, Go Fuseya, Satoshi Takeya, Akihiro Hachikubo
Summary: Carbon isotope fractionation was observed during the formation of CO2 hydrates, with δ13C of hydrate-bound CO2 lower than that of residual CO2. The difference in equilibrium pressures between (CO2)-C-12 and (CO2)-C-13 hydrates caused approximately 1 parts per thousand carbon isotope fractionation. More accurate pressure measurements are needed for quantitative discussions in (CO2)-C-12-H2O and (CO2)-C-13-H2O systems.
Review
Chemistry, Analytical
Monica Marini, Francesca Legittimo, Bruno Torre, Marco Allione, Tania Limongi, Luciano Scaltrito, Candido Fabrizio Pirri, Enzo di Fabrizio
Summary: This review examines the various methods, technologies, and materials dedicated to DNA research, focusing on the tailored and combined applications of DNA nanotechnology, micro-fabrication, imaging, and spectroscopies in medical-oriented fields. Recent advancements in miniaturization of devices, as well as the ongoing need to study biological material structures and interactions down to single molecules, have increased the interdisciplinary nature of emerging technologies.
Article
Energy & Fuels
Liu Chuanhai, Chen Ran, Zhang Baoyong, Wu Qiang, Zhang Qiang, Gao Xia, Wu Qiong
Summary: The accurate determination of coal mine gas separation product characteristics is essential for gas separation applications. Gas hydrates synthesized from gases with different compositions were analyzed using in situ Raman spectroscopy. The study found that the crystal structure of the mixed-gas hydrate is stable in the presence of 75% CO2 compared to 70% CO2, with large cages being predominantly occupied by guest molecules while small cages are not easily occupied.
FRONTIERS IN ENERGY RESEARCH
(2021)
Article
Crystallography
Hironobu Machida, Takeshi Sugahara, Hiroyasu Masunaga, Izumi Hirasawa
JOURNAL OF CRYSTAL GROWTH
(2020)
Article
Engineering, Chemical
Jin Shimada, Masami Shimada, Takeshi Sugahara, Katsuhiko Tsunashima, Yuta Takaoka, Atsushi Tani
Summary: This study investigated the impact of cation size and shape on the thermodynamic properties of semiclathrate hydrates, finding that branched alkyl groups raised the equilibrium temperature while shorter alkyl groups lowered it. Among the orthorhombic systems studied, semiclathrate hydrates with higher equilibrium temperatures had larger dissociation enthalpies.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Thermodynamics
Shunsuke Hashimoto, Kazuhisa Yano, Yasuki Hirota, Hiroshi Uchiyama, Satoshi Tsutsui
Summary: The study demonstrates that adding a small amount of SiO2 nanoparticles to nanofluids can enhance thermal conductivity beyond theoretical values, and the high-frequency sound velocity can provide insights into the relationship between solvent molecular relaxation and thermal conductivity. Different sizes of SiO2 particles have varying effects on the high-frequency sound velocity and thermal conductivity of ethylene glycol aqueous solution.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Jin Shimada, Moe Yamada, Atsushi Tani, Takeshi Sugahara, Katsuhiko Tsunashima, Yusuke Tsuchida, Takayuki Hirai
Summary: The thermodynamic properties of SCHs are influenced by the steric conformations of the guest anions. Different guest anions have varying effects on the equilibrium temperatures of SCHs, with some exhibiting similar temperatures while others show higher temperatures. Anion size and conformation play a critical role in determining the stability and properties of SCHs.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2022)
Article
Chemistry, Physical
Shunsuke Hashimoto, Kenji Nakajima, Tatsuya Kikuchi, Kazuya Kamazawa, Kaoru Shibata, Takeshi Yamada
Summary: QENS and PFG-NMR analyses were performed on a nanofluid containing SiO2 nanoparticles and ethylene glycol aqueous solution. The results showed that SiO2 particles may decrease the self-diffusion coefficient of liquid molecules, leading to an increase in thermal conductivity of the nanofluid.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Thermodynamics
Sakura Azuma, Jin Shimada, Katsuhiko Tsunashima, Takeshi Sugahara, Atsushi Tani, Takayuki Hirai
Summary: The present study investigates the thermodynamic stability of semiclathrate hydrates (SCHs) of tri-n-butylalkenylphosphonium bromide (P444(alkenyl)-Br: alkenyl = 3-butenyl (3.1) or 4-pentenyl (4.1)). The introduction of double bonds is found to lower the equilibrium temperature of the SCHs and affect their dissociation enthalpy.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2022)
Article
Engineering, Chemical
Shunsuke Hashimoto, Takafumi Yamauchi
Summary: This study evaluates the heat transfer coefficients and friction factors of nanofluids composed of ethylene glycol aqueous solution and oxide-ceramic nanoparticles in a resistive-heated cylindrical channel. The experimental results show that the measured heat transfer coefficients are higher than the estimated coefficients based on the nanofluids' thermophysical properties. The difference between the experimental and estimated coefficients follows the order of the absolute zeta potential value of the nanofluids, indicating the importance of particle dispersibility. The heat exchange output in the nanofluids is in agreement with the order of their zeta potential values.
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
(2022)
Article
Chemistry, Physical
Shunsuke Hashimoto, Satoshi Yamaguchi, Masashi Harada, Kenji Nakajima, Tatsuya Kikuchi, Kazuki Ohishi
Summary: In recent research, it has been found that nanofluids composed of base liquids and dispersed solid nanoparticles show an anomalous improvement in thermal conductivity compared to the predicted value. By using various techniques, the study provides solid evidence that the vibrational behavior of liquid molecules around nanoparticles contributes significantly to the increased thermal conductivity. The vibration of liquid molecules is found to be equivalent to phonon conduction in solids, leading to a solid-like behavior in the liquid.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Sakura Azuma, Jin Shimada, Katsuhiko Tsunashima, Takeshi Sugahara, Takayuki Hirai
Summary: In this study, a novel type of ionic clathrate hydrate with high equilibrium temperature and dissociation enthalpy was developed for thermal storage applications.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Thermodynamics
Jin Shimada, Masami Shimada, Sakura Azuma, Takeshi Sugahara, Katsuhiko Tsunashima, Takayuki Hirai
Summary: The phase equilibrium (temperature-composition) relations of the TBP-TFA + water binary system were investigated, including solid-liquid and liquid-liquid equilibria. The phase diagram of TBP-TFA SCH showed peritectic behavior, with a decomposition temperature of 275.9 +/- 0.1 K and a stoichiometric composition of 0.027 +/- 0.002 mole fraction. The decomposition enthalpy of TBP-TFA SCH was determined to be 199 +/- 2 J/g. Above the LCST, liquid-liquid phase separation occurred, and the composition at the LCST was found to be similar to the stoichiometric composition of TBP-TFA SCH, indicating similar cluster-based solution structures.
FLUID PHASE EQUILIBRIA
(2023)
Article
Physics, Applied
Jin Shimada, Atsushi Tani, Takeshi Yamada, Takeshi Sugahara, Takayuki Hirai, Takuo Okuchi
Summary: The dynamics of water molecules in tetra-n-butyl-d36-ammonium bromide semiclathrate hydrate were studied, revealing a fast reorientation motion of water molecules in the temperature range of 212-278 K. The mean jump distance of hydrogen atoms was found to be within 1.5-2.0A degrees, with a relaxation time of 100-410 ps and an activation energy of 10.2 +/- 5.8 kJ/mol. This short relaxation time is possibly due to the strong interaction between a bromide anion and its surrounding water molecules, suggesting a unique strategy for designing efficient, safe, and inexpensive proton conductors using semiclathrate hydrates.
APPLIED PHYSICS LETTERS
(2023)
Article
Thermodynamics
Kazuhiro Minamikawa, Jin Shimada, Takeshi Sugahara, Takayuki Hirai
Summary: This study investigates environmentally friendly semiclathrate hydrates (SCHs) and finds that they are suitable phase change materials for cold energy storage. They can be used as refrigerants in the logistics of vegetables and fruits to preserve their freshness.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2023)
Article
Chemistry, Multidisciplinary
Hironobu Machida, Takeshi Sugahara, Izumi Hirasawa
Summary: This study investigated the effect of various additives on the degree of supercooling in the formation of THF hydrate. It was found that adding AgO or Ag3PO4 can effectively reduce the degree of supercooling. Raman spectra and scanning transmission electron microscopy revealed that AgO or Ag3PO4 can form coordination bonds with THF molecules and accelerate cluster formation, thus diminishing the supercooling.
Article
Chemistry, Physical
Kouji Maeda, Masato Moritoki, Shinji Yae, Keisuke Fukui, Naoki Fukumuro, Takeshi Sugahara
Summary: The study found that pressurizing an AAA battery with Ar or N-2 at pressures of up to 5 MPa can significantly enhance its durability, even under high-current conditions. The research proposes a different reaction mechanism to explain how pressure affects the durability improvement.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Hironobu Machida, Takeshi Sugahara, Izumi Hirasawa
Summary: Understanding the mechanism by which silver nanoparticles promote crystallization of supercooled aqueous solutions is crucial for designing semiclathrate hydrates for latent heat storage materials. This study reveals that silver nanoparticles accelerate cluster formation, leading to a phase change from supercooled droplets to ice grains. The discovery provides insights into heterogeneous nucleation during a phase change and has potential implications for enhancing production efficiency and quality of manufactured products.
COMMUNICATIONS MATERIALS
(2021)
