Parameter Screening of PVDF/PVP Multi-Channel Capillary Membranes

The increasing research in the field of polymeric multi-channel membranes has shown that their mechanical stability is beneficial for a wide range of applications. The more complex interplay of formation process parameters compared to a single-channel geometry makes an investigation using Design of Experiments (DoE) appealing. In this study, seven-channel capillary membranes were fabricated in a steam–dry–wet spinning process, while varying the composition of the polymer solution and the process temperatures in a three-level fractional factorial linear screening design. The polymers polyvinylidene flouride (PVDF) was the chemically resistant main polymer and polyvinylpyrrolidone (PVP) was added as hydrophilic co-polymer. Scanning electron microscopy and atomic force microscopy were applied to study the membrane morphology. Fabrication process conditions were established to yield PVDF/PVP multi-channel membranes, which reached from high flux (permeability P = 321.4 L / m 2 / h /bar, dextran 500 kDa retention R = 18.3%) to high retention (P = 66.8 L / m 2 / h /bar, R = 80.0%). The concentration of the main polymer PVDF and the molecular weight of the co-polymer PVP showed linear relations with both P and R. The permeability could be increased using sodium hypochlorite post-treatment, although retention was slightly compromised. The obtained membranes may be suitable for micro- or ultra-filtration and, at the same time, demonstrate the merits and limitations of DoE for multi-channel membrane screening.

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The Statistical Optimisation of Recombinant β-glucosidase Production through a Two-Stage, Multi-Model, Design of Experiments Approach

Bioengineering ◽

10.3390/bioengineering6030061 ◽

2019 ◽

Vol 6 (3) ◽

pp. 61

Author(s):

Albert Uhoraningoga ◽

Gemma K. Kinsella ◽

Jesus M. Frias ◽

Gary T. Henehan ◽

Barry J. Ryan

Keyword(s):

Design Of Experiments ◽

Incubation Time ◽

Metal Ion ◽

Streptomyces Griseus ◽

Fold Increase ◽

Fractional Factorial ◽

Model Design ◽

Two Stage ◽

Screening Design ◽

Wide Range

β-glucosidases are a class of enzyme that are widely distributed in the living world, with examples noted in plants, fungi, animals and bacteria. They offer both hydrolysis and synthesis capacity for a wide range of biotechnological processes. However, the availability of native, or the production of recombinant β-glucosidases, is currently a bottleneck in the widespread industrial application of this enzyme. In this present work, the production of recombinant β-glucosidase from Streptomyces griseus was optimised using a Design of Experiments strategy, comprising a two-stage, multi-model design. Three screening models were comparatively employed: Fractional Factorial, Plackett-Burman and Definitive Screening Design. Four variables (temperature, incubation time, tryptone, and OD600 nm) were experimentally identified as having statistically significant effects on the production of S.griseus recombinant β-glucosidase in E. coli BL21 (DE3). The four most influential variables were subsequently used to optimise recombinant β-glucosidase production, employing Central Composite Design under Response Surface Methodology. Optimal levels were identified as: OD600 nm, 0.55; temperature, 26 °C; incubation time, 12 h; and tryptone, 15 g/L. This yielded a 2.62-fold increase in recombinant β-glucosidase production, in comparison to the pre-optimised process. Affinity chromatography resulted in homogeneous, purified β-glucosidase that was characterised in terms of pH stability, metal ion compatibility and kinetic rates for p-nitrophenyl-β-D-glucopyranoside (pNPG) and cellobiose catalysis.

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Electron microscopy study of reactively sputter-deposited Ti/N films on silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131449 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1362-1363

Author(s):

V. C. Kannan ◽

A. K. Singh ◽

R. B. Irwin ◽

S. Chittipeddi ◽

F. D. Nkansah ◽

...

Keyword(s):

Integrated Circuits ◽

Large Scale ◽

Hexagonal Phase ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Process Conditions ◽

Tin Films ◽

Wide Range ◽

Fcc Phase ◽

Circuits Vlsi

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.

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Discovery of Antibacterial Agents Inhibiting the Energy-Coupling Factor (ECF) Transporters by Structure-Based Virtual Screening

10.26434/chemrxiv.11728710 ◽

2020 ◽

Author(s):

Eleonora Diamanti ◽

Inda Setyawati ◽

Spyridon Bousis ◽

leticia mojas ◽

lotteke Swier ◽

...

Keyword(s):

Virtual Screening ◽

Antibacterial Agents ◽

Antimicrobial Agents ◽

Energy Coupling ◽

Coupling Factor ◽

Design Synthesis ◽

Screening Design ◽

Starting Point ◽

Wide Range ◽

Vitamin Uptake

Here, we report on the virtual screening, design, synthesis and structure–activity relationships (SARs) of the first class of selective, antibacterial agents against the energy-coupling factor (ECF) transporters. The ECF transporters are a family of transmembrane proteins involved in the uptake of vitamins in a wide range of bacteria. Inhibition of the activity of these proteins could reduce the viability of pathogens that depend on vitamin uptake. Because of their central role in the metabolism of bacteria and their absence in humans, ECF transporters are novel potential antimicrobial targets to tackle infection. The hit compound’s metabolic and plasma stability, the potency (20, MIC Streptococcus pneumoniae = 2 µg/mL), the absence of cytotoxicity and a lack of resistance development under the conditions tested here suggest that this scaffold may represent a promising starting point for the development of novel antimicrobial agents with an unprecedented mechanism of action.<br>

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An Investigation on the Performance of an Oxidation Catalyst Using Two-dimensional Simulation with Detailed Reaction Mechanism

Chemical Product and Process Modeling ◽

10.1515/cppm-2019-0115 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Sreeharsh Nair ◽

Mayank Mittal

Keyword(s):

Single Channel ◽

Catalytic Converter ◽

Oxidation Catalyst ◽

Low Temperature Combustion ◽

Wide Range ◽

Detailed Reaction Mechanism ◽

Temperature Combustion ◽

High Concentrations ◽

Dimensional Simulation ◽

Surface Reaction Kinetics

AbstractThe advent of stricter emission standards has increased the importance of aftertreatment devices and the role of numerical simulations in the evolution of better catalytic converters in order to satisfy these emission regulations. In this paper, a 2-D numerical simulation of a single channel of the monolith catalytic converter is presented by using detailed surface reaction kinetics aiming to investigate the chemical behaviour inside the converter. The model has been developed to study the conversion of carbon monoxide (CO) in the presence of propene (C3H6) for low-temperature combustion (LTC) engine application. The inhibition effect of C3H6 over a wide range of CO inlet concentrations is investigated. Considering both low and high levels of CO concentration at the inlet, the 2-D model predicted better results than their corresponding 1-D counterparts when compared with the experimental data from literature. It was also observed that C3H6 inhibition at high temperatures was significant, particularly for high concentrations of CO compared to low concentrations of CO at the inlet.

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Phase equilibria modeling of biorefinery-related systems: a systematic review

Chemical Product and Process Modeling ◽

10.1515/cppm-2020-0119 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Marcos L. Corazza ◽

Julia Trancoso

Keyword(s):

Phase Equilibria ◽

Phase Behavior ◽

Fossil Fuel ◽

Process Conditions ◽

Design And Optimization ◽

Waste Reuse ◽

Wide Range ◽

Prisma Statement ◽

Fuel Substitution ◽

The Subject

Abstract The search for sustainable ideas has gained prominence in recent decades at all levels of society since it has become imperative an economic, social, and environmental development in an integrated manner. In this context, biorefineries are currently present as the technology that best covers all these parameters, as they add the benefits of waste reuse, energy cogeneration, and fossil fuel substitution. Thus, the study of the various applicable biological matrices and exploring the technical capabilities of these processes become highly attractive. Thermodynamic modeling acts in this scenario as a fundamental tool for phase behavior predictions in process modeling, design, and optimization. Thus, this work aimed to systematize, using the PRISMA statement for systematic reviews, the information published between 2010 and 2020 on phase equilibria modeling in systems related to biorefineries to organize what is already known about the subject. As a result, 236 papers were categorized in terms of the year, country, type of phase equilibria, and thermodynamic model used. Also, the phase behavior predictions of different thermodynamic models under the same process conditions were qualitatively compared, establishing PC-SAFT as the model that best represents the great diversity of interest systems for biorefineries in a wide range of conditions.

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Lipase Immobilization in Mesoporous Silica Nanoparticles for Biofuel Production

Catalysts ◽

10.3390/catal11050629 ◽

2021 ◽

Vol 11 (5) ◽

pp. 629

Author(s):

Aniello Costantini ◽

Valeria Califano

Keyword(s):

Mesoporous Silica ◽

Silica Nanoparticles ◽

Mechanical Stability ◽

Mesoporous Silica Nanoparticles ◽

Physiological Role ◽

Biodiesel Production ◽

Biofuel Production ◽

Hydroxyl Groups ◽

Lipase Immobilization ◽

Wide Range

Lipases are ubiquitous enzymes whose physiological role is the hydrolysis of triacylglycerol into fatty acids. They are the most studied and industrially interesting enzymes, thanks to their versatility to promote a plethora of reactions on a wide range of substrates. In fact, depending on the reaction conditions, they can also catalyze synthesis reactions, such as esterification, acidolysis and transesterification. The latter is particularly important for biodiesel production. Biodiesel can be produced from animal fats or vegetable oils and is considered as a biodegradable, non-toxic and renewable energy source. The use of lipases as industrial catalysts is subordinated to their immobilization on insoluble supports, to allow multiple uses and use in continuous processes, but also to stabilize the enzyme, intrinsically prone to denaturation with consequent loss of activity. Among the materials that can be used for lipase immobilization, mesoporous silica nanoparticles represent a good choice due to the combination of thermal and mechanical stability with controlled textural characteristics. Moreover, the presence of abundant surface hydroxyl groups allows for easy chemical surface functionalization. This latter aspect has the main importance since lipases have a high affinity with hydrophobic supports. The objective of this work is to provide an overview of the recent progress of lipase immobilization in mesoporous silica nanoparticles with a focus on biodiesel production.

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Wear Resistance of (Ti,Al)N Metallic Coatings for Extremal Working Conditions

Coatings ◽

10.3390/coatings11020157 ◽

2021 ◽

Vol 11 (2) ◽

pp. 157

Author(s):

Jarosław Mikuła ◽

Daniel Pakuła ◽

Ludwina Żukowska ◽

Klaudiusz Gołombek ◽

Antonín Kříž

Keyword(s):

Wear Resistance ◽

Functional Properties ◽

Tool Life ◽

Cutting Tools ◽

Hard Coatings ◽

Metallographic Analysis ◽

Process Conditions ◽

Tool Materials ◽

Coated Materials ◽

Wide Range

The article includes research results for the functional properties achieved for a wide range of sintered tool materials, including sintered carbides, cermets and three types of Al2O3 oxide tool ceramics ((Al2O3 + ZrO2, Al2O3 + TiC and Al2O3 + SiC(w)) with (Ti,Al)N coating deposited in the cathodic arc evaporation (CAE-PVD) method and comparison with uncoated tool materials. For all coated samples, a uniform wear pattern on tool shank was observed during metallographic analysis. Based on the scanning electron microscope (SEM) metallographic analysis, it was found that the most common types of tribological defects identified in tested materials are: mechanical defects and abrasive wear of the tool side, crater formation on the tool face, cracks on the tool side, chipping on the cutting edge and built-up edge from chip fragments. Deposition of (Ti,Al)N coating on all tested substrates increases the wear resistance and also limits the exceeding of critical levels of permanent stresses. It even increases the tool life many times over. Such a significant increase in tool life results, among other things, from a large increase in microhardness of PVD coated materials compared to uncoated samples, increased resistance to thermal and chemical abrasion, improved chip formation and removal process conditions. Use of hard coatings applied to sintered tool materials is considered to be one of the most important achievements in improving the functional properties of cutting tools and can still be developed by improving the coating structure solutions (sorted and nanocrystalline structures) and extending the range of coating applications (Ti,Al)N in a variety of substrates.

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A New Flexible Rapid Thermal Processing System

MRS Proceedings ◽

10.1557/proc-389-307 ◽

1995 ◽

Vol 389 ◽

Author(s):

K. C. Saraswat ◽

Y. Chen ◽

L. Degertekin ◽

B. T. Khuri-Yakub

Keyword(s):

Control System ◽

Real Time ◽

Processing System ◽

Process Conditions ◽

Temperature Uniformity ◽

Real Time Control ◽

Wafer Temperature ◽

Time Control ◽

Wide Range ◽

Optical Flux

ABSTRACTA highly flexible Rapid Thermal Multiprocessing (RTM) reactor is described. This flexibility is the result of several new innovations: a lamp system, an acoustic thermometer and a real-time control system. The new lamp has been optimally designed through the use of a “virtual reactor” methodology to obtain the best possible wafer temperature uniformity. It consists of multiple concentric rings composed of light bulbs with horizontal filaments. Each ring is independently and dynamically controlled providing better control over the spatial and temporal optical flux profile resulting in excellent temperature uniformity over a wide range of process conditions. An acoustic thermometer non-invasively allows complete wafer temperature tomography under all process conditions - a critically important measurement never obtained before. For real-time equipment and process control a model based multivariable control system has been developed. Extensive integration of computers and related technology for specification, communication, execution, monitoring, control, and diagnosis demonstrates the programmability of the RTM.

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Efficient approximations for stationary single-channel Ca2+ nanodomains across length scales

10.1101/2020.01.16.909036 ◽

2020 ◽

Cited By ~ 1

Author(s):

Y Chen ◽

C Muratov ◽

V Matveev

Keyword(s):

Parameter Space ◽

Single Channel ◽

Asymptotic Series ◽

Rational Functions ◽

Great Accuracy ◽

Model Parameters ◽

Relevant Parameter ◽

Buffer Concentration ◽

Computationally Efficient ◽

Wide Range

ABSTRACTWe consider the stationary solution for the Ca2+ concentration near a point Ca2+ source describing a single-channel Ca2+ nanodomain, in the presence of a single mobile Ca2+ buffer with one-to-one Ca2+ binding. We present computationally efficient approximants that estimate stationary single-channel Ca2+ nanodomains with great accuracy in broad regions of parameter space. The presented approximants have a functional form that combines rational and exponential functions, which is similar to that of the well-known Excess Buffer Approximation and the linear approximation, but with parameters estimated using two novel (to our knowledge) methods. One of the methods involves interpolation between the short-range Taylor series of the buffer concentration and its long-range asymptotic series in inverse powers of distance from the channel. Although this method has already been used to find Padé (rational-function) approximants to single-channel Ca2+ and buffer concentration, extending this method to interpolants combining exponential and rational functions improves accuracy in a significant fraction of the relevant parameter space. A second method is based on the variational approach, and involves a global minimization of an appropriate functional with respect to parameters of the chosen approximations. Extensive parameter sensitivity analysis is presented, comparing these two methods with previously developed approximants. Apart from increased accuracy, the strength of these approximants is that they can be extended to more realistic buffers with multiple binding sites characterized by cooperative Ca2+ binding, such as calmodulin and calretinin.STATEMENT OF SIGNIFICANCEMathematical and computational modeling plays an important role in the study of local Ca2+ signals underlying vesicle exocysosis, muscle contraction and other fundamental physiological processes. Closed-form approximations describing steady-state distribution of Ca2+ in the vicinity of an open Ca2+ channel have proved particularly useful for the qualitative modeling of local Ca2+ signals. We present simple and efficient approximants for the Ca2+ concentration in the presence of a mobile Ca2+ buffer, which achieve great accuracy over a wide range of model parameters. Such approximations provide an efficient method for estimating Ca2+ and buffer concentrations without resorting to numerical simulations, and allow to study the qualitative dependence of nanodomain Ca2+ distribution on the buffer’s Ca2+ binding properties and its diffusivity.

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Application of SU-8 photoresist as a multi-functional structural dielectric layer in FOWLP

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/2017dpc-tp2_presentation3 ◽

2017 ◽

Vol 2017 (DPC) ◽

pp. 1-19

Author(s):

Raquel Pinto ◽

André Cardoso ◽

Sara Ribeiro ◽

Carlos Brandão ◽

João Gaspar ◽

...

Keyword(s):

Structural Material ◽

High Performance ◽

Microelectromechanical Systems ◽

Low Cost ◽

Process Conditions ◽

Processing Temperature ◽

Wafer Level ◽

Fast Growing ◽

Wide Range ◽

Different Types

Microelectromechanical Systems (MEMS) are a fast growing technology for sensor and actuator miniaturization finding more and more commercial opportunities by having an important role in the field of Internet of Things (IoT). On the same note, Fan-out Wafer Level Packaging (FOWLP), namely WLFO technology of NANIUM, which is based on Infineon/ Intel eWLB technology, is also finding further applications, not only due to its high performance, low cost, high flexibility, but also due to its versatility to allow the integration of different types of components in the same small form-factor package. Despite its great potential it is still off limits to the more sensitive components as micro-mechanical devices and some type of sensors, which are vulnerable to temperature and pressure. In the interest of increasing FOWLP versatility and enabling the integration of MEMS, new methods of assembling and processing are continuously searched for. Dielectrics currently used for redistribution layer construction need to be cured at temperatures above 200°C, making it one of the major boundary for low temperature processing. In addition, in order to accomplish a wide range of dielectric thicknesses in the same package it is often necessary to stack very different types of dielectrics with impact on bill of materials complexity and cost. In this work, done in cooperation with the International Iberian Nanotechnology Laboratory (INL), we describe the implementation of commercially available SU-8 photoresist as a structural material in FOWLP, allowing lower processing temperature and reduced internal package stress, thus enabling the integration of components such as MEMS/MOEMS, magneto-resistive devices and micro-batteries. While SU-8 photoresist was first designed for the microelectronics industry, it is currently highly used in the fabrication of microfluidics as well as microelectromechanical systems (MEMS) and BIO-MEMS due to its high biocompatibility and wide range of available thicknesses in the same product family. Its good thermal and chemical resistance and also mechanical and rheological properties, make it suitable to be used as a structural material, and moreover it cures at 150°C, which is key for the applications targeted. Unprecedentedly, SU-8 photoresist is tested in this work as a structural dielectric for the redistribution layers on 300mm fan-out wafers. Main concerns during the evaluation of the new WLFO dielectric focused on processability quality; adhesion to multi-material substrate and metals (copper, aluminium, gold, ¦); between layers of very different thicknesses; and overall reliability. During preliminary runs, processability on 300 mm fan-out wafers was evaluated by testing different coating and soft bake conditions, exposure settings, post-exposure parameters, up to developing setup. The outputs are not only on process conditions and results but also on WLFO design rules. For the first time, a set of conditions has been defined that allows processing SU-8 on WLFO, with thickness values ranging from 1 um to 150 um. The introduction of SU-8 in WLFO is a breakthrough in this fast-growing advanced packaging technology platform as it opens vast opportunities for sensor integration in WLP technology.

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