The impact of the silica gel structure and surface chemistry on the melting of aliphatic nanocrystals: Thermodynamic model and experiment

2022 ◽  
Vol 161 ◽  
pp. 110426
Author(s):  
Maxim M. Lazarenko ◽  
Sergei A. Alekseev ◽  
Kateryna I. Hnatiuk ◽  
Roman V. Dinzhos ◽  
Maksym S. Nizameev ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Silica Gel ◽  
Thermodynamic Model ◽  
Gel Structure ◽  
The Impact

scholarly journals The Role of Surface Chemistry in the Efficacy of Protein and DNA Microarrays for Label-Free Detection: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1026
Author(s):  
Elisa Chiodi ◽  
Allison M. Marn ◽  
Matthew T. Geib ◽  
M. Selim Ünlü
Keyword(s):  
Surface Chemistry ◽  
Surface Functionalization ◽  
Dna Microarrays ◽  
Label Free ◽  
Polymeric Coatings ◽  
Label Free Detection ◽  
Particle Imaging ◽  
Single Particle Imaging ◽  
The Impact

The importance of microarrays in diagnostics and medicine has drastically increased in the last few years. Nevertheless, the efficiency of a microarray-based assay intrinsically depends on the density and functionality of the biorecognition elements immobilized onto each sensor spot. Recently, researchers have put effort into developing new functionalization strategies and technologies which provide efficient immobilization and stability of any sort of molecule. Here, we present an overview of the most widely used methods of surface functionalization of microarray substrates, as well as the most recent advances in the field, and compare their performance in terms of optimal immobilization of the bioreceptor molecules. We focus on label-free microarrays and, in particular, we aim to describe the impact of surface chemistry on two types of microarray-based sensors: microarrays for single particle imaging and for label-free measurements of binding kinetics. Both protein and DNA microarrays are taken into consideration, and the effect of different polymeric coatings on the molecules’ functionalities is critically analyzed.

scholarly journals Impact of the Simulated Gastric Digestion Methodology on the In Vitro Intestinal Proteolysis and Lipolysis of Emulsion Gels

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 321
Author(s):  
Camila Mella ◽  
Michelle Quilaqueo ◽  
Rommy N. Zúñiga ◽  
Elizabeth Troncoso
Keyword(s):  
Heat Treatment ◽  
Protein Isolate ◽  
Gastric Digestion ◽  
Human Gastrointestinal Tract ◽  
Gel Structure ◽  
Intestinal Digestion ◽  
Food Digestion ◽  
The Impact ◽  
Digestion Methods

The aim of this work was to study the impact of the methodology of in vitro gastric digestion (i.e., in terms of motility exerted and presence of gastric emptying) and gel structure on the degree of intestinal proteolysis and lipolysis of emulsion gels stabilized by whey protein isolate. Emulsions were prepared at pH 4.0 and 7.0 using two homogenization pressures (500 and 1000 bar) and then the emulsions were gelled by heat treatment. These gels were characterized in terms of texture analysis, and then were subjected to one of the following gastric digestion methods: in vitro mechanical gastric system (IMGS) or in vitro gastric digestion in a stirred beaker (SBg). After gastric digestion, the samples were subjected to in vitro intestinal digestion in a stirred beaker (SBi). Hardness, cohesiveness, and chewiness were significantly higher in gels at pH 7.0. The degree of proteolysis was higher in samples digested by IMGS–SBi (7–21%) than SBg–SBi (3–5%), regardless of the gel’s pH. For SBg–SBi, the degree of proteolysis was not affected by pH, but when operating the IMGS, higher hydrolysis values were obtained for gels at pH 7.0 (15–21%) than pH 4.0 (7–13%). Additionally, the percentage of free fatty acids (%FFA) released was reduced by 47.9% in samples digested in the IMGS–SBi. For the methodology SBg–SBi, the %FFA was not affected by the pH, but in the IMGS, higher values were obtained for gels at pH 4.0 (28–30%) than pH 7.0 (15–19%). Our findings demonstrate the importance of choosing representative methods to simulate food digestion in the human gastrointestinal tract and their subsequent impact on nutrient bioaccessibility.

scholarly journals The Effect of Adhesive Additives on Silica Gel Water Sorption Properties

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 327
Author(s):  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Agata Mlonka-Medrala ◽  
Wojciech Nowak ◽  
Łukasz Mika ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Silica Gel ◽  
Water Sorption ◽  
High Reliability ◽  
Electricity Consumption ◽  
Hydroxyethyl Cellulose ◽  
Poly Vinyl Alcohol ◽  
Dynamic Adsorption ◽  
Metal Plates ◽  
The Impact

Adsorption chillers are characterized by low electricity consumption, lack of moving parts, and high reliability. The disadvantage of these chillers is their large weight due to low adsorbent sorption capacity. Therefore, the attention is turned to finding a sorbent with a high water sorption capacity and enhanced thermal conductivity to increase chiller efficiency. The article discusses the impact of selected adhesives used for the production of an adsorption bed in order to improve heat exchange on its surface. Experiments with silica gel with three commercial types of glue on metal plates representing heat exchanger were performed. The structure of samples was observed under a microscope to determine the coverage of adsorbent by glue. To determine the kinetics of the free adsorption, the amounts of moisture adsorbed and the desorption dynamics the prepared samples of coated bed on metal plates were moisturized and dried in a moisture analyzer. Samples made of silica gel mixed with the adhesive 2-hydroxyethyl cellulose, show high adsorption capacity, low dynamic adsorption, and medium dynamic desorption. Samples containing adhesive poly(vinyl alcohol) adsorb less moisture, but free adsorption and desorption were more dynamic. Samples containing the adhesive hydroxyethyl cellulose show lower moisture capacity, relatively dynamic adsorption, and lower dynamic desorption.

scholarly journals The impact of surface chemistry and texture on the CO2 uptake capacity of graphene oxide

2018 ◽  
Vol 482 ◽  
pp. 470-477 ◽  
Author(s):  
Amira Alazmi ◽  
Omar El Tall ◽  
Mohamed N. Hedhili ◽  
Pedro M.F.J. Costa
Keyword(s):  
Graphene Oxide ◽  
Surface Chemistry ◽  
Co2 Uptake ◽  
Uptake Capacity ◽  
The Impact

Trends in COP for Adsorption Cooling Cycles With Thermal Regeneration and Finite Number of Beds

2008 ◽  
Author(s):  
Derek K. Baker ◽  
Bilgin Kaftanog˘lu
Keyword(s):  
Finite Number ◽  
Silica Gel ◽  
Thermodynamic Model ◽  
Adsorption Process ◽  
Optimum Distribution ◽  
Thermal Regeneration ◽  
Desorption Process ◽  
Cooling Cycle ◽  
Bed Temperature ◽  
Ability To Regenerate

A thermodynamic model is developed to predict trends in limiting COP of an adsorption cooling cycle with thermal regeneration between n beds, where n is any even number and each bed is spatially isothermal. The results of the model indicate the optimum distribution of beds throughout the cycle to maximize thermal regeneration. Simulations were run for silica gel-water and zeolite-water adsorbent-refrigerant pairs as the maximum bed temperature and the bed’s sensible load were varied. For the silica gel-water pair, the exothermic adsorption process occurs at lower temperatures than the endothermic desorption process, which prevents the latent loads from being thermally regenerated. This inability to regenerate latent loads results in a relatively small opportunity to increase COP through thermal regeneration, and this opportunity decreases rapidly with increasing number of beds. Conversely, for the zeolite-water pair much of the exothermic adsorption process occurs over the same temperature range as the endothermic desorption process, which allows a significant portion of the latent loads to be thermally regenerated. This ability to regenerate latent loads results in a much larger opportunity to increase COP through thermal regeneration, and this opportunity decreases much more gradually with increasing number of beds.

Impact of surface chemistry and topography on the function of antigen presenting cells

2015 ◽  
Vol 3 (3) ◽  
pp. 424-441 ◽  
Author(s):  
H. M. Rostam ◽  
S. Singh ◽  
N. E. Vrana ◽  
M. R. Alexander ◽  
A. M. Ghaemmaghami
Keyword(s):  
Surface Chemistry ◽  
Surface Topography ◽  
Antigen Presenting Cells ◽  
Biomaterial Surface ◽  
And Function ◽  
Antigen Presenting ◽  
The Impact

The impact of biomaterial surface topography and chemistry on antigen presenting cells’ phenotype and function.

scholarly journals THERMODYNAMIC MODEL OF AERODYNAMIC SOUND HARDENING METHOD

2020 ◽  
Vol 4 (53) ◽  
pp. 65-69
Author(s):  
Anatoliy N. JIGALOV ◽  
◽  
Valeriy K. SHELEG ◽  
Dmitriy D. BOGDAN ◽  
◽  
...  
Keyword(s):  
Impact Toughness ◽  
Hard Alloy ◽  
Thermodynamic Model ◽  
Thermodynamic System ◽  
Initial Structure ◽  
Hard Alloys ◽  
Resonant Amplitude ◽  
Aerodynamic Sound ◽  
Wave Effects ◽  
The Impact

As a result of scientific research, a method of aerodynamic sound hardening (ADH) has been developed and patented, which makes it possible to achieve improved properties of hard alloys by reducing their defectiveness, improving the homogeneity of the structure. The physics of the ADH process is that the hardened product is preheated to an acceptable temperature at which the hard alloy does not lose the plasticity and hardness acquired during manufacture. Then the product is exposed to sound frequency waves, reduced in the range of 140...160 Hz into a resonant state, in which the formation of a resonant amplitude increased by several hundred times occurs. The article gives a description of the essence of the created ADH method. The dependence for determining the action energy on a hardened solid by ADH is provided. A thermodynamic model of the ADH method is presented, based on energy thermal and wave effects on the hardened structure. On the basis of the thermodynamic explanation, the ADH method is reduced to a change in the initial structure of the hard alloy under the influence of temperature and wave resonant energy fluxes on it, through which activating and dissipative processes of energy outflow are excited in the hardening object in the mode of an open thermodynamic system. In addition, the quasi-static process of wave energy transfer, carried out in a non-equilibrium medium, significantly exceeds the relaxation time of the strengthening system. When hardening by ADH, the impact toughness increases by 19–23 % in hard alloys, while the values of impact toughness equal to 39.54–42.05 kJ/m2 are achieved, the hardness according to the HRC parameter increases by 3.0–5.2 %.

The In Situ Adaptive Tabulation (ISAT) Algorithm for Reacting Flow Computations With Complex Surface Chemistry

2013 ◽  
Author(s):  
Sandip Mazumder ◽  
Ankan Kumar
Keyword(s):  
Steady State ◽  
Surface Chemistry ◽  
Catalytic Combustion ◽  
Catalytic Converter ◽  
Differential Algebraic Equations ◽  
Heterogeneous Reactions ◽  
Reacting Flow ◽  
In Situ Adaptive Tabulation ◽  
The Impact

The In Situ Adaptive Tabulation (ISAT) procedure, originally developed for the efficient computation of homogeneous reactions in chemically reacting flows, is adapted and demonstrated for reacting flow computations with complex heterogeneous (or surface) reactions. The treatment of heterogeneous reactions within a reacting flow calculation requires solution of a set of nonlinear differential algebraic equations at boundary faces/nodes, as opposed to the solution of an initial value problem for which the original ISAT procedure was developed. The modified ISAT algorithm, referred to as ISAT-S, is coupled to a three-dimensional unstructured reacting flow solver, and strategies for maximizing efficiency without hampering accuracy and convergence are developed. These include use of multiple binary tables, use of dynamic tolerance values to control errors, and periodic deletion and/or re-creation of the binary tables. The new procedure is demonstrated for steady-state catalytic combustion of a methane-air mixture on platinum using a 24-step reaction mechanism with 19 species, and for steady-state three-way catalytic conversion using a 61-step mechanism with 34 species. Both reaction mechanisms are first tested in simple 3D channel geometry with reacting walls, and the impact of various ISAT parameters is investigated. As a final step, the catalytic combustion mechanism is demonstrated in a laboratory-scale monolithic catalytic converter geometry with 57 channels discretized using 354,300 control volumes (4.6 million unknowns). For all of the cases considered, the reduction in the time taken to perform surface chemistry calculations alone was found to be a factor of 5–11.

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