Article
Engineering, Aerospace
Boris Smorodin, Ivan Cherepanov
Summary: This study investigates the convection of colloidal suspension in a horizontal layer using a bidisperse model, considering the influence of the Soret effect and gravitational sedimentation of nanoparticles. The characteristics of the bidisperse model and the instability boundaries are analyzed.
MICROGRAVITY SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Ivan Cherepanov, Boris Smorodin
Summary: This study investigates two-dimensional oscillatory flows in a convective cell filled with a colloidal suspension. The nanoparticle transport mechanisms are analyzed and the spatiotemporal characteristics of the stable traveling waves are determined. The dependence of the Rayleigh number on the Lewis number at the boundary of existence of the stable traveling wave is obtained.
EUROPEAN PHYSICAL JOURNAL E
(2022)
Review
Optics
K. Monisha, K. Suresh, Sajan D. George
Summary: The conversion of light to heat via the photothermal effect has been used to evaluate thermo-optic properties of materials, but recently it has also been used for the manipulation of colloidal objects and living cells. Optothermal manipulation techniques utilize lower optical power and can manipulate particles over a long range compared to conventional optical tweezers. This review discusses the working mechanisms, concepts, and applications of recently established optothermal techniques, as well as the physical mechanisms behind the optical manipulation.
LASER & PHOTONICS REVIEWS
(2023)
Article
Thermodynamics
Khalil Ur Rehman, Wasfi Shatanawi, Mostafa Zahri, El-Sayed M. Sherif, Harri Junaedi, Yu-Pei Lv
Summary: The study focuses on heat transfer analysis of partially heated non-Newtonian liquid suspensions in closed square enclosures equipped with porous media. Using finite element method and hybrid meshing, the research investigates the impact of natural convection and porous media on fluid properties.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Biochemical Research Methods
Tetsuro Tsuji, Satoshi Taguchi, Hiroki Takamatsu
Summary: This study experimentally investigates the significance of thermophoresis and thermal convection on particle transport in a heated liquid phase by changing the gap size. Results show a threshold gap size where particles accumulate around the heated spot above the threshold, forming a ring-like distribution, while below the threshold particles are depleted from the spot. Switching between accumulation and depletion modes may lead to novel manipulation techniques.
Article
Thermodynamics
Wenhao Cao, I. L. Animasaun, Se-Jin Yook, V. A. Oladipupo, Xianjun Ji
Summary: This study investigates the flow characteristics of ternary-hybrid nanofluids and their influence under temperature difference, nonlinear thermal radiation, and partial slip. The results show that partial slip reduces the friction at the wall, with the lowest decreasing rate observed in free convection. When induced by mixed convection, the increased motion of the three types of nanoparticles leads to optimal mass and heat transfer rates.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Physical
Chandra Has, P. Sunthar
Summary: When a liquid is forced through a second liquid with different density or viscosity, the interface can become unstable, resulting in finger-like patterns. Specifically, colloidal fingers form when a colloidal suspension is placed above a miscible liquid of higher mass density.
COLLOID AND INTERFACE SCIENCE COMMUNICATIONS
(2021)
Article
Mechanics
I. N. Cherepanov, B. L. Smorodin
Summary: Numerical simulations were conducted for the convection in a horizontally filled colloidal suspension under non-uniform heating condition, revealing the accumulation of heavy impurities and transfer through convection. The study also analyzed the stable oscillatory nonlinear convection regimes observed in the experiment.
JOURNAL OF APPLIED MECHANICS AND TECHNICAL PHYSICS
(2021)
Article
Thermodynamics
S. A. M. Mehryan, Piran Goudarzi, Seyed Mohsen Hashem Zadeh, Maryam Ghodrat, Obai Younis, Mohammad Ghalambaz
Summary: This study investigates the thermal convection heat transfer of a hybrid nanofluid in a square cavity subjected to gravitational and vibrational forces. The results reveal that external vibration amplifies the rate of heat transfer, while the effect of nanoparticle concentration on heat transfer intensity varies with time.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Physics, Multidisciplinary
Leiqi Yuan, Shufan Zou, Yantao Yang, Shiyi Chen
Summary: In this study, a novel strategy is proposed to enhance heat transfer in convection turbulence. By introducing a standing-wave type boundary deformation, flow modulation can be achieved when the amplitude is comparable or larger than the boundary-layer thickness. The heat-flux enhancement primarily occurs in the near-wall regions affected by the boundary deformation at large wave numbers. The findings suggest that oscillating deformations of the boundary can effectively break the boundary layers and open new possibilities for modulating convection turbulence.
PHYSICAL REVIEW LETTERS
(2023)
Article
Thermodynamics
C. J. Ho, C. Y. Huang, Chi-Ming Lai
Summary: In this study, numerical simulation was used to investigate oscillatory natural convection in a square enclosure with a phase change material suspension. The results show that oscillations occur not only at high Rayleigh numbers, but also under low Rayleigh number conditions when the initial mass fraction or subcooling is increased, or the Stefan number is decreased.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Mechanics
Changwoo Kang, Harunori N. Yoshikawa, Parisa Mirbod
Summary: This study investigates thermal convection in neutrally buoyant, non-colloidal suspensions confined between horizontal plates using a constitutive diffusion equation coupled with flow equations. The model proposed by Metzger et al. for effective thermal diffusivity of suspensions is employed. Results show that the critical Rayleigh number gradually increases with bulk particle volume fraction, enhancing heat transfer, and the heat transfer is affected by shear-induced particle migration.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Andreas D. Demou, Mehdi Niazi Ardekani, Parisa Mirbod, Luca Brandt
Summary: This study presents direct numerical simulations of turbulent Rayleigh-Benard convection in non-colloidal suspensions, with special focus on the heat transfer modifications in the flow. The research found that the Nusselt number weakly but steadily increases when the particle volume fraction is below 25%, mainly due to increased thermal agitation. However, when the particle volume fraction exceeds 30%, the Nusselt number exhibits a substantial drop, attributed to the dense particle layering in the near-wall region, which reduces convection and inhibits the formation of coherent structures near the wall.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Thermodynamics
Shafia Rana, M. Nawaz, Sayer Obaid Alharbi
Summary: Theoretical investigation on the use of hybrid nanoparticles to enhance the effective thermal conductivity of micropolar fluids over a non-uniformly moving surface exposed to a non-uniform magnetic field is conducted. The study shows that an increase in vortex viscosity leads to a rise in microrotation velocity but a decrease in macro-velocity. Both vortex viscosity and spin gradient viscosity have a significant impact on temperature, with higher viscosities resulting in lower temperatures. Furthermore, the effect of these viscosities on temperature is more pronounced in micropolar mixtures containing Cu and Al2O3 compared to those containing only copper particles.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Engineering, Chemical
Mehdi Ghalambaz, S. A. M. Mehryan, Kasra Ayoubi Ayoubloo, Ahmad Hajjar, Mohammad S. Islam, Obai Younis, Abdelraheem M. Aly
Summary: The energy storage capability of Nano-Encapsulated Phase Change Material (NEPCM) nanoparticles in an enclosure during the charging and discharging process was investigated. The study found that an increase in the volume fraction of nanoparticles led to a rise in the rate of heat transfer and total energy storage. Additionally, decreasing the Stefan number increased the total stored energy, and the fusion temperature played a significant role in the energy storage behavior.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Polymer Science
Jacek Walkowiak, Yan Lu, Michael Gradzielski, Stefan Zauscher, Matthias Ballauff
MACROMOLECULAR RAPID COMMUNICATIONS
(2020)
Article
Agronomy
Anita Freundorfer, Ingo Rehberg, Beverly E. Law, Christoph Thomas
AGRICULTURAL AND FOREST METEOROLOGY
(2019)
Article
Biochemistry & Molecular Biology
Jacek Janusz Walkowiak, Matthias Ballauff, Ralf Zimmermann, Uwe Freudenberg, Carsten Werner
Article
Materials Science, Multidisciplinary
Ingo Rehberg, Reinhard Richter, Stefan Hartung
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2020)
Article
Engineering, Chemical
Daniel Besold, Sebastian Risse, Yan Lu, Joachim Dzubiella, Matthias Ballauff
Summary: The kinetic study on the reduction of 4-nitrophenol with borohydride catalyzed by silver nanoparticles showed that the particles are immobilized deep inside a PNIPAM hydrogel shell. A kinetic model related to the analysis of the reaction catalyzed by gold was presented, with results fitting well and indicating the substantial influence of NH2 adsorption on the kinetics of silver. The study also revealed a non-Arrhenius dependency of the reaction rate at different temperatures, caused by the thermoresponsive PNIPAM hydrogel, and provided insights into the partitioning coefficients of reactants and products in PNIPAM-based catalysts.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Nanoscience & Nanotechnology
Arne Ronneburg, Luca Silvi, Joshaniel Cooper, Karsten Harbauer, Matthias Ballauff, Sebastian Risse
Summary: The lithiation of crystalline silicon was studied using operando neutron reflectometry over six cycles, revealing the effects of an artificial aluminum oxide coating on suppressing the solid electrolyte interphase layer-related aging effects and increasing lithium trapping. Two distinct zones with high and low lithium concentrations were found in the silicon, separated by a broadening sharp interface. Neutron reflectometry, electrochemical analysis, and impedance spectroscopy were used to quantify lithium distribution and consumption within the silicon.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Jacek J. Walkowiak, Matthias Ballauff
Summary: The theoretical model presented in this study accounts for the free energy Delta G(b) of complex formation between a highly charged polyelectrolyte and a protein, taking into consideration the effect of released counterions and the uptake or release of water molecules. The model can describe the dependence of Delta G(b) on temperature and salt concentration, with an increase in salt concentration making counterion release less effective for binding and leading to a more advantageous release of water molecules during complex formation. Experimental data on complex formation between synthetic and natural polyelectrolytes and proteins shows agreement with the theory.
Article
Biochemistry & Molecular Biology
Chuanxiong Nie, Anil Kumar Sahoo, Roland R. Netz, Andreas Herrmann, Matthias Ballauff, Rainer Haag
Summary: The novel SARS-CoV-2 mutant Omicron, with its over 60 mutations, is likely to spread and dominate worldwide. The higher infection potential of Omicron may be attributed to the increased occurrence of positively charged amino acids in its spike protein, resulting in enhanced binding to cellular receptors.
Article
Chemistry, Physical
Weronika Malicka, Rainer Haag, Matthias Ballauff
Summary: This study presents a thermodynamic investigation of the interaction between heparin and lysozyme in the presence of potassium glutamate (KGlu). The results show that increasing KGlu concentration decreases the binding free energy due to counterion release and changes in hydration. The characteristic temperature in the presence of KGlu is smaller than that in the presence of NaCl, and the change in specific heat becomes more negative with increasing salt concentration.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Materials Science, Multidisciplinary
Simeon Voelkel, Stefan Hartung, Ingo Rehberg
Summary: This paper examines the hysteretic transition between two stable arrangements of a cluster of seven dipoles, and clarifies the nature of the two instabilities. The first one is a symmetry-breaking sub-critical bifurcation, and the second one is a fold.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Biochemistry & Molecular Biology
Dusica Maysinger, Issan Zhang, Pei You Wu, Marten Kagelmacher, Haiming Daniel Luo, Jayachandran N. Kizhakkedathu, Jens Dernedde, Matthias Ballauf, Rainer Haag, Adeola Shobo, Gerhard Multhaup, R. Anne McKinney
Summary: The objective of this study was to investigate the interaction between polyglycerols with sulfate or sialic acid functional groups and high mobility group box 1 (HMGB1). The study aimed to determine if polyglycerols could prevent the loss of morphological plasticity in excitatory neurons in the hippocampus. The results suggest that dendritic and linear polyglycerols can interact with HMGB1 and prevent dendritic spine loss in excitatory neurons.
ACS CHEMICAL NEUROSCIENCE
(2023)
Article
Biochemistry & Molecular Biology
Uwe Freudenberg, Passant Atallah, Jens-Uwe Sommer, Carsten Werner, Matthias Ballauff
Summary: A model is proposed to explain the interaction between biological signaling proteins and highly charged polymer networks. The model takes into account the immobilization of counterions on highly charged chains and the Donnan equilibrium between the network and the aqueous solution. The model accurately compares with experimental data on biohybrid polymer networks interacting with signaling proteins.
MACROMOLECULAR BIOSCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Frank Mickoleit, Cornelia Joerke, Reinhard Richter, Sabine Rosenfeldt, Simon Markert, Ingo Rehberg, Anna S. S. Schenk, Oliver Baeumchen, Dirk Schueler, Joachim H. H. Clement
Summary: Through long-term storage experiments, it was found that the magnetic potency of magnetic particles decreases by about one-third, but the particle size distribution, integrity of the surrounding magnetosome membrane, colloidal stability, and biocompatibility are not severely affected.
Article
Chemistry, Multidisciplinary
Matthias Ballauff
Summary: This article investigates the transition of proteins in aqueous solution with various salts or uncharged solutes. A phenomenological model is presented to describe the effect of solute concentration on transition temperature, taking into account the change in the number of counterions and hydration. The results highlight the influence of ions and hydration on the free energy of transition, providing insights into the physical mechanisms underlying protein transitions.
Article
Materials Science, Multidisciplinary
Ingo Rehberg, Reinhard Richter, Stefan Hartung, Niklas Lucht, Birgit Hankiewicz, Thomas Friedrich
