Orientation of Janus particles under thermal fields: The role of internal mass anisotropy

2020 ◽  
Vol 152 (20) ◽  
pp. 204902 ◽  
Author(s):  
Juan D. Olarte-Plata ◽  
Fernando Bresme
Keyword(s):  
Janus Particles ◽  
Internal Mass ◽  
Thermal Fields

scholarly journals Substrate wettability guided oriented self assembly of Janus particles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meneka Banik ◽  
Shaili Sett ◽  
Chirodeep Bakli ◽  
Arup Kumar Raychaudhuri ◽  
Suman Chakraborty ◽  
...  
Keyword(s):  
Self Assembly ◽  
Janus Particles ◽  
Water Molecules ◽  
Functional Coatings ◽  
Hexagonal Close Packed ◽  
Local Densities ◽  
Inhomogeneous Properties ◽  
Metal Polymer ◽  
Specific Orientation

AbstractSelf-assembly of Janus particles with spatial inhomogeneous properties is of fundamental importance in diverse areas of sciences and has been extensively observed as a favorably functionalized fluidic interface or in a dilute solution. Interestingly, the unique and non-trivial role of surface wettability on oriented self-assembly of Janus particles has remained largely unexplored. Here, the exclusive role of substrate wettability in directing the orientation of amphiphilic metal-polymer Bifacial spherical Janus particles, obtained by topo-selective metal deposition on colloidal Polymestyere (PS) particles, is explored by drop casting a dilute dispersion of the Janus colloids. While all particles orient with their polymeric (hydrophobic) and metallic (hydrophilic) sides facing upwards on hydrophilic and hydrophobic substrates respectively, they exhibit random orientation on a neutral substrate. The substrate wettability guided orientation of the Janus particles is captured using molecular dynamic simulation, which highlights that the arrangement of water molecules and their local densities near the substrate guide the specific orientation. Finally, it is shown that by spin coating it becomes possible to create a hexagonal close-packed array of the Janus colloids with specific orientation on differential wettability substrates. The results reported here open up new possibilities of substrate-wettability driven functional coatings of Janus particles, which has hitherto remained unexplored.

scholarly journals Investigating the effects of substrate morphology and experimental conditions on the enzymatic hydrolysis of lignocellulosic biomass through modeling

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jessica C. Rohrbach ◽  
Jeremy S. Luterbacher
Keyword(s):  
Mass Transfer ◽  
Lignocellulosic Biomass ◽  
Concentration Gradient ◽  
Internal Mass ◽  
Enzyme Loading ◽  
Experimental Conditions ◽  
Biomass Deconstruction ◽  
Internal Mass Transfer ◽  
Cellulose Surface

Abstract Background Understanding how the digestibility of lignocellulosic biomass is affected by its morphology is essential to design efficient processes for biomass deconstruction. In this study, we used a model based on a set of partial differential equations describing the evolution of the substrate morphology to investigate the interplay between experimental conditions and the physical characteristics of biomass particles as the reaction proceeds. Our model carefully considers the overall quantity of cellulase present in the hydrolysis mixture and explores its interplay with the available accessible cellulose surface. Results Exploring the effect of various experimental and structural parameters highlighted the significant role of internal mass transfer as the substrate size increases and/or the enzyme loading decreases. In such cases, diffusion of cellulases to the available cellulose surface limits the rate of glucose release. We notably see that increasing biomass loading, while keeping enzyme loading constant should be favored for both small- (R < 300 $$\mu m$$ μ m ) and middle-ranged (300 < R < 1000 $$\mu m$$ μ m ) substrates to enhance enzyme diffusion while minimizing the use of enzymes. In such cases, working at enzyme loadings exceeding the full coverage of the cellulose surface (i.e. eI>1) does not bring a significant benefit. For larger particles (R > 1000 $$\mu m$$ μ m ), increases in biomass loading do not offset the significant internal mass transfer limitations, but high enzyme loadings improve enzyme penetration by maintaining a high concentration gradient within the particle. We also confirm the well-known importance of cellulose accessibility, which increases with pretreatment. Conclusions Based on the developed model, we are able to propose several design criteria for deconstruction process. Importantly, we highlight the crucial role of adjusting the enzyme and biomass loading to the wood particle size and accessible cellulose surface to maintain a strong concentration gradient, while avoiding unnecessary excess in cellulase loading. Theory-based approaches that explicitly consider the entire lignocellulose particle structure can be used to clearly identify the relative importance of bottlenecks during the biomass deconstruction process, and serve as a framework to build on more detailed cellulase mechanisms.

Behavior of Janus Particles at Liquid Interfaces

2014 ◽  
Author(s):  
Hossein Rezvantalab ◽  
Shahab Shojaei-Zadeh
Keyword(s):  
Small Difference ◽  
Separation Distance ◽  
Janus Particles ◽  
Interface Plane ◽  
Fluid Interfaces ◽  
Liquid Interfaces ◽  
Ellipsoidal Particles ◽  
Particle Force ◽  
Energetic Interactions

We study the capillary-induced interactions and configuration of spherical and non-spherical Janus particles adsorbed at flat liquid-fluid interfaces. For Janus spheres, the equilibrium orientation results in each hemisphere being exposed to its more favored fluid. However, experimental observations suggest that some of these particles may take a tilted orientation at the interface, giving rise to a deformed interface. On the other hand, Janus ellipsoids with a large aspect ratio or a small difference in the wettability of the two regions tend to tilt even at equilibrium. The overlap of deformed menisci results in energetic interactions between neighboring particles. We numerically calculate the interface shape around the particles by minimizing the total surface energy of the system comprising of the interface and particle-fluid regions. We quantify these interactions through evaluation of capillary energy variation as a function of the orientation and separation distance between the particles. We find that Janus spheres with similar orientations undergo a relative realignment in the interface plane in order to minimize the capillary energy. In case of ellipsoidal particles, the particles assemble in a preferred side-by-side configuration. We evaluate the role of anisotropy and degree of amphiphilicity on the inter-particle force and the capillary torque. The results can be used to predict the migration and oriented assembly of Janus particles with various geometrical and surface properties at liquid-fluid interfaces.

Role of Geometry and Amphiphilicity on Capillary-Induced Interactions between Anisotropic Janus Particles

Langmuir ◽  
2013 ◽  
Vol 29 (48) ◽  
pp. 14962-14970 ◽  
Author(s):  
Hossein Rezvantalab ◽  
Shahab Shojaei-Zadeh
Keyword(s):  
Janus Particles

The role of external and internal mass transfer in the process of Cu2+removal by natural mineral sorbents

2011 ◽  
Vol 32 (9) ◽  
pp. 933-943 ◽  
Author(s):  
M. Šljivić ◽  
I. Smičiklas ◽  
I. Plećaš ◽  
S. Pejanović
Keyword(s):  
Mass Transfer ◽  
Internal Mass ◽  
Natural Mineral ◽  
Internal Mass Transfer

scholarly journals Janus Particles at Fluid Interfaces: Stability and Interfacial Rheology

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 374
Author(s):  
Elton L. Correia ◽  
Nick Brown ◽  
Sepideh Razavi
Keyword(s):  
Colloidal Particles ◽  
Janus Particles ◽  
Shear Stresses ◽  
Fluid Interfaces ◽  
Interfacial Rheology ◽  
Pickering Emulsions ◽  
Interfacial Mechanics ◽  
Anisotropic Surface ◽  
Particle Anisotropy

The use of the Janus motif in colloidal particles, i.e., anisotropic surface properties on opposite faces, has gained significant attention in the bottom-up assembly of novel functional structures, design of active nanomotors, biological sensing and imaging, and polymer blend compatibilization. This review is focused on the behavior of Janus particles in interfacial systems, such as particle-stabilized (i.e., Pickering) emulsions and foams, where stabilization is achieved through the binding of particles to fluid interfaces. In many such applications, the interface could be subjected to deformations, producing compression and shear stresses. Besides the physicochemical properties of the particle, their behavior under flow will also impact the performance of the resulting system. This review article provides a synopsis of interfacial stability and rheology in particle-laden interfaces to highlight the role of the Janus motif, and how particle anisotropy affects interfacial mechanics.

scholarly journals Variations in intensity and structure of a westward-propagating monsoon depression

MAUSAM ◽  
2022 ◽  
Vol 44 (3) ◽  
pp. 231-238
Author(s):  
KSHUDIRAM SAHA ◽  
SURANJANA SAHA
Keyword(s):  
Bay Of Bengal ◽  
Arabian Sea ◽  
Heat Budget ◽  
Central India ◽  
Monsoon Depression ◽  
Pressure System ◽  
Thermal Fields ◽  
The North ◽  
Low Pressure System

The study deals with a monsoon depression which developed over the Bay of Bengal, moved westward across central India and turned into a mid-tropospheric disturbance (MTD) over the northeastern : corner of the Arabian Sea. Its interactions with the thermal fields associated with the basic monsoon, subtropical westerly troughs and a new depression over the Bay of Bengal are examined. Evidence suggests the involvement of all the three factors in causing the observed variations in its intensity and structure. The low pressure system turned into a mid-tropospheric disturbance when it re-entered the warm sector of the basic monsoon field and received increased warm advection from the north to the west of its centre and cold advection from the south to the east in mid-troposphere. The importance of thermal advection is confirmed by computation of a heat budget. The role of condensation heating is also briefly discussed.  

scholarly journals BIẾN ĐỘNG CỦA TRƯỜNG NHIỆT ĐỘ VÀ MỐI QUAN HỆ CỦA NÓ VỚI ENSO TRONG VÙNG BIỂN NINH THUẬN - BÌNH THUẬN

2018 ◽  
Vol 18 (1) ◽  
pp. 79-87
Author(s):  
Tran Van Chung ◽  
Nguyen Huu Huan ◽  
Bui Hong Long ◽  
Nguyen Truong Thanh Hoi ◽  
Phan Thanh Bac
Keyword(s):  
Temperature Fields ◽  
Climate Variations ◽  
Forecast System ◽  
Climate Forecast System ◽  
Climate Forecast System Reanalysis ◽  
Thermal Fields ◽  
Spatial Changes ◽  
Recent Climate ◽  
Environmental Prediction

In this paper, our aim was to examine the role of ENSO in the recent climate variations. Analyzed results on temporal variability of thermal fields in period of 38 years (Jan. 1979-Aug. 2016) showed that Ninh Thuan - Binh Thuan waters were subjected to the significant impact of the ENSO phases (warming and cooling) as well as other processes related to seasonal, inter-seasonal, yearly and mutlti-yearly variations such as in the periods 1986-1989, 1996-2000 and 2009-2011. In order to clarify above issues, authors carried out the analysis of the temporal -spatial changes of temperature fields (include air temperature and sea surface temperature) in Ninh Thuan - Binh Thuan region. The temperature data were exploited from The National Centers for Environmental Prediction (NCEP) and Climate Forecast System Reanalysis (CFSR) in the form of hourly time-series products with spatial resolution of 0.3o (1979-2010) and 0.20o (2011-8/2016). The results showed that 2016 was quite similar to 1998 and 2010 when the coral bleaching occurred in the study area.

scholarly journals Aspects Regarding of a UGV Fire Fighting Thermal Shield

2021 ◽  
Vol 6 (1) ◽  
pp. 83
Author(s):  
Lucian Ștefăniță Grigore ◽  
Amado Ștefan ◽  
Ionica Oncioiu ◽  
Cristian Molder ◽  
Damian Gorgoteanu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Power Supply ◽  
Thermal Protection ◽  
Fire Investigation ◽  
Thermal Shield ◽  
Emergency Situations ◽  
Thermal Fields ◽  
Very High ◽  
Blind Spots

This article presents aspects related to the protection (with a double shield made of stainless steel) of a robot for emergency situations against the effect of flames due to a fire. The ground robot is semi-autonomous/autonomous, with a wheeled propeller (6 × 6). The robot, designed and built at the TRL 2 level, is intended for fire investigation, monitoring, and intervention (and, in particular, for petrochemical plants). The role of the shield is to protect the equipment that is part of the robot including its controllers, sensors, communications, power supply, etc. The need to mount a thermal protection shield on the intervention robot was given by the fact that fires at petrochemical plants generate very large thermal fields and gradients which are responsible for creating blind spots. These blind spots do not allow intervention crews to see what is happening in that area. These blind spots are characterized by very high temperatures. The dynamics of these fires can be unpredictable. Therefore, to analyze the performance of the heat shield in this study we perform a numerical-experimental analysis.

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