scholarly journals Lignin-Based Polyurethanes: Opportunities for Bio-Based Foams, Elastomers, Coatings and Adhesives

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1202 ◽  
Author(s):  
Mona Alinejad ◽  
Christián Henry ◽  
Saeid Nikafshar ◽  
Akash Gondaliya ◽  
Sajad Bagheri ◽  
...  
Keyword(s):  
Polymeric Materials ◽  
Cellulosic Biofuels ◽  
Market Segments ◽  
Extraction Recovery ◽  
Aromatic Polymer ◽  
Current State ◽  
Lignin Extraction ◽  
Wide Range ◽  
Chemical Pulping ◽  
Structure Diversity

Polyurethane chemistry can yield diverse sets of polymeric materials exhibiting a wide range of properties for various applications and market segments. Utilizing lignin as a polyol presents an opportunity to incorporate a currently underutilized renewable aromatic polymer into these products. In this work, we will review the current state of technology for utilizing lignin as a polyol replacement in different polyurethane products. This will include a discussion of lignin structure, diversity, and modification during chemical pulping and cellulosic biofuels processes, approaches for lignin extraction, recovery, fractionation, and modification/functionalization. We will discuss the potential of incorporation of lignins into polyurethane products that include rigid and flexible foams, adhesives, coatings, and elastomers. Finally, we will discuss challenges in incorporating lignin in polyurethane formulations, potential solutions and approaches that have been taken to resolve those issues.

Young Scholars Conference “Slavic World: Commonality and Diversity”. 21–22 May 2019. Session “Linguistics”

2019 ◽  
Vol 14 (1-2) ◽  
pp. 295-297
Author(s):  
Sergej A. Borisov
Keyword(s):  
Czech Republic ◽  
Middle Ages ◽  
The Czech Republic ◽  
International Context ◽  
Slavic Languages ◽  
Russian Academy Of Sciences ◽  
Current State ◽  
Wide Range ◽  
History Of ◽  
Academy Of Sciences

For more than twenty years, the Institute of Slavic Studies of the Russian Academy of Sciences celebrates the Day of Slavic Writing and Culture with a traditional scholarly conference.”. Since 2014, it has been held in the young scholars’ format. In 2019, participants from Moscow, St. Petersburg, Kazan, Togliatti, Tyumen, Yekaterinburg, and Rostov-on-Don, as well as Slovakia, the Czech Republic, Hungary, and Romania continued this tradition. A wide range of problems related to the history of the Slavic peoples from the Middle Ages to the present time in the national, regional and international context were discussed again. Participants talked about the typology of Slavic languages and dialects, linguo-geography, socio- and ethnolinguistics, analyzed formation, development, current state, and prospects of Slavic literatures, etc.

scholarly journals β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

2021 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Georgi G. Gochev ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Valentin B. Fainerman ◽  
Reinhard Miller
Keyword(s):  
Theoretical Description ◽  
Fluid Interfaces ◽  
Interfacial Behavior ◽  
Current State ◽  
Air Interface ◽  
Direct Measurements ◽  
Wide Range ◽  
Dilational Viscoelasticity ◽  
Parameter Values ◽  
Β Lactoglobulin

The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

scholarly journals Recent Advances in Fabrication of Non-Isocyanate Polyurethane-Based Composite Materials

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3497
Author(s):  
Piotr Stachak ◽  
Izabela Łukaszewska ◽  
Edyta Hebda ◽  
Krzysztof Pielichowski
Keyword(s):  
Raw Materials ◽  
Synthesis Method ◽  
Polymeric Materials ◽  
Original Research ◽  
Significant Group ◽  
Oh Groups ◽  
New Class ◽  
Hazardous Chemical ◽  
Wide Range

Polyurethanes (PUs) are a significant group of polymeric materials that, due to their outstanding mechanical, chemical, and physical properties, are used in a wide range of applications. Conventionally, PUs are obtained in polyaddition reactions between diisocyanates and polyols. Due to the toxicity of isocyanate raw materials and their synthesis method utilizing phosgene, new cleaner synthetic routes for polyurethanes without using isocyanates have attracted increasing attention in recent years. Among different attempts to replace the conventional process, polyaddition of cyclic carbonates (CCs) and polyfunctional amines seems to be the most promising way to obtain non-isocyanate polyurethanes (NIPUs) or, more precisely, polyhydroxyurethanes (PHUs), while primary and secondary –OH groups are being formed alongside urethane linkages. Such an approach eliminates hazardous chemical compounds from the synthesis and leads to the fabrication of polymeric materials with unique and tunable properties. The main advantages include better chemical, mechanical, and thermal resistance, and the process itself is invulnerable to moisture, which is an essential technological feature. NIPUs can be modified via copolymerization or used as matrices to fabricate polymer composites with different additives, similar to their conventional counterparts. Hence, non-isocyanate polyurethanes are a new class of environmentally friendly polymeric materials. Many papers on the matter above have been published, including both original research and extensive reviews. However, they do not provide collected information on NIPU composites fabrication and processing. Hence, this review describes the latest progress in non-isocyanate polyurethane synthesis, modification, and finally processing. While focusing primarily on the carbonate/amine route, methods of obtaining NIPU are described, and their properties are presented. Ways of incorporating various compounds into NIPU matrices are characterized by the role of PHU materials in copolymeric materials or as an additive. Finally, diverse processing methods of non-isocyanate polyurethanes are presented, including electrospinning or 3D printing.

scholarly journals Status of Phenological Research Using Sentinel-2 Data: A Review

2020 ◽  
Vol 12 (17) ◽  
pp. 2760
Author(s):  
Gourav Misra ◽  
Fiona Cawkwell ◽  
Astrid Wingler
Keyword(s):  
Vegetation Index ◽  
Temporal Frequency ◽  
Short Wave ◽  
Current State ◽  
Red Edge ◽  
Natural Grasslands ◽  
Wide Range ◽  
Normalised Difference Vegetation Index ◽  
Satellite Sensors ◽  
Sentinel 2

Remote sensing of plant phenology as an indicator of climate change and for mapping land cover has received significant scientific interest in the past two decades. The advancing of spring events, the lengthening of the growing season, the shifting of tree lines, the decreasing sensitivity to warming and the uniformity of spring across elevations are a few of the important indicators of trends in phenology. The Sentinel-2 satellite sensors launched in June 2015 (A) and March 2017 (B), with their high temporal frequency and spatial resolution for improved land mapping missions, have contributed significantly to knowledge on vegetation over the last three years. However, despite the additional red-edge and short wave infra-red (SWIR) bands available on the Sentinel-2 multispectral instruments, with improved vegetation species detection capabilities, there has been very little research on their efficacy to track vegetation cover and its phenology. For example, out of approximately every four papers that analyse normalised difference vegetation index (NDVI) or enhanced vegetation index (EVI) derived from Sentinel-2 imagery, only one mentions either SWIR or the red-edge bands. Despite the short duration that the Sentinel-2 platforms have been operational, they have proved their potential in a wide range of phenological studies of crops, forests, natural grasslands, and other vegetated areas, and in particular through fusion of the data with those from other sensors, e.g., Sentinel-1, Landsat and MODIS. This review paper discusses the current state of vegetation phenology studies based on the first five years of Sentinel-2, their advantages, limitations, and the scope for future developments.

scholarly journals Antioxidant Activity in Bee Products: A Review

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
Marianna Martinello ◽  
Franco Mutinelli
Keyword(s):  
Analytical Methods ◽  
Nutritional Value ◽  
Royal Jelly ◽  
Antioxidant Activities ◽  
Natural Antioxidants ◽  
Bioactive Substances ◽  
Current State ◽  
Wide Range ◽  
Ancient Times ◽  
Antioxidant Characteristics

Bee products have been used since ancient times both for their nutritional value and for a broad spectrum of therapeutic purposes. They are deemed to be a potential source of natural antioxidants that can counteract the effects of oxidative stress underlying the pathogenesis of many diseases. In view of the growing interest in using bioactive substances from natural sources to promote health and reduce the risk of developing certain illnesses, this review aims to update the current state of knowledge on the antioxidant capacity of bee products such as honey, pollen, propolis, beeswax, royal jelly and bee venom, and on the analytical methods used. The complex, variable composition of these products and the multitude of analytical methods used to study their antioxidant activities are responsible for the wide range of results reported by a plethora of available studies. This suggests the need to establish standardized methods to more efficiently evaluate the intrinsic antioxidant characteristics of these products and make the data obtained more comparable.

Future trends in diagnosis using laboratory-on-a-chip technologies

Parasitology ◽  
1999 ◽  
Vol 117 (7) ◽  
pp. 191-203 ◽  
Author(s):  
M. S. TALARY ◽  
J. P. H. BURT ◽  
R. PETHIG
Keyword(s):  
Gene Expression ◽  
Lower Cost ◽  
Building Blocks ◽  
Cancer Diagnostics ◽  
Future Trends ◽  
Biotechnological Applications ◽  
Environmental Testing ◽  
Current State ◽  
Microelectronic Fabrication ◽  
Wide Range

There has been an enormous growth in the development of biotechnological applications, where advances in the techniques of microelectronic fabrication and the technologies of miniaturization and integration in semiconductor industries are being applied to the production of Laboratory-on-a-Chip devices. The aim of this development is to create devices that will perform the same processes that are currently carried out in the laboratory in reduced timescales, at a lower cost, requiring less reagents, and with a greater resolution of detection and specificity. The expectations of this Laboratory-on-a-Chip revolution is that this technology will facilitate rapid advances in gene discovery, genetic mapping and gene expression with broader applications ranging from infectious diseases and cancer diagnostics to food quality and environmental testing. A review of the current state of development in this field reveals the scale of the ongoing revolution and serves to highlight the advances that can be perceived in the development of Laboratory-on-a-Chip technologies. Since miniaturization can be applied to such a wide range of laboratory processes, some of the sub-units that can be used as building blocks in these devices are described, with a brief description of some of the fabrication processes that can be used to create them.

scholarly journals Introduction to redundancy rules: the continuous wavelet transform comes of age

2018 ◽  
Vol 376 (2126) ◽  
pp. 20170258 ◽  
Author(s):  
Paul S. Addison
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
State Of The Art ◽  
Structural Characteristics ◽  
Continuous Wavelet ◽  
Theme Issue ◽  
Current State ◽  
Analysis Methods ◽  
Wide Range ◽  
New Form

Redundancy: it is a word heavy with connotations of lacking usefulness. I often hear that the rationale for not using the continuous wavelet transform (CWT)—even when it appears most appropriate for the problem at hand—is that it is ‘redundant’. Sometimes the conversation ends there, as if self-explanatory. However, in the context of the CWT, ‘redundant’ is not a pejorative term, it simply refers to a less compact form used to represent the information within the signal. The benefit of this new form—the CWT—is that it allows for intricate structural characteristics of the signal information to be made manifest within the transform space, where it can be more amenable to study: resolution over redundancy. Once the signal information is in CWT form, a range of powerful analysis methods can then be employed for its extraction, interpretation and/or manipulation. This theme issue is intended to provide the reader with an overview of the current state of the art of CWT analysis methods from across a wide range of numerate disciplines, including fluid dynamics, structural mechanics, geophysics, medicine, astronomy and finance. This article is part of the theme issue ‘Redundancy rules: the continuous wavelet transform comes of age’.

scholarly journals A Brief Overview of Social Network Analysis and its Current State within Romanian Sociology

2013 ◽  
Vol 3 (3) ◽  
pp. 5-11
Author(s):  
Marian-Gabriel Hâncean
Keyword(s):  
Social Network ◽  
Social Network Analysis ◽  
Network Analysis ◽  
International Relations ◽  
Early Spring ◽  
Research Topics ◽  
Political Sciences ◽  
Current State ◽  
Wide Range ◽  
Network Studies

Abstract The field of social network studies has been growing within the last 40 years, gathering scholars from a wide range of disciplines (biology, chemistry, geography, international relations, mathematics, political sciences, sociology etc.) and covering diverse substantive research topics. Using Google metrics, the scientific production within the field it is shown to follow an ascending trend since the late 60s. Within the Romanian sociology, social network analysis is still in his early spring, network studies being low in number and rather peripheral. This note gives a brief overview of social network analysis and makes some short references to the current state of the network studies within Romanian sociology

scholarly journals Comparative Assessment of Tungsten Toxicity in the Absence or Presence of Other Metals

Toxics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 66 ◽  
Author(s):  
Ola Wasel ◽  
Jennifer Freeman
Keyword(s):  
Human Exposure ◽  
Potable Water ◽  
Comparative Assessment ◽  
Tungsten Alloy ◽  
Tungsten Alloys ◽  
Mechanisms Of Toxicity ◽  
Adverse Health Effects ◽  
Current State ◽  
Wide Range ◽  
Military Applications

Tungsten is a refractory metal that is used in a wide range of applications. It was initially perceived that tungsten was immobile in the environment, supporting tungsten as an alternative for lead and uranium in munition and military applications. Recent studies report movement and detection of tungsten in soil and potable water sources, increasing the risk of human exposure. In addition, experimental research studies observed adverse health effects associated with exposure to tungsten alloys, raising concerns on tungsten toxicity with questions surrounding the safety of exposure to tungsten alone or in mixtures with other metals. Tungsten is commonly used as an alloy with nickel and cobalt in many applications to adjust hardness and thermal and electrical conductivity. This review addresses the current state of knowledge in regard to the mechanisms of toxicity of tungsten in the absence or presence of other metals with a specific focus on mixtures containing nickel and cobalt, the most common components of tungsten alloy.

Training Standards for Career Child Psychiatrists

1982 ◽  
Vol 27 (7) ◽  
pp. 543-545
Author(s):  
Philip Barker
Keyword(s):  
Full Range ◽  
Clinical Work ◽  
Psychiatric Training ◽  
Current State ◽  
Child Psychiatric ◽  
Wide Range ◽  
Training Standards ◽  
Special Expertise ◽  
Mentally Retarded Children ◽  
Main Components

The two main components of child psychiatric training should be supervised clinical work of high quality and training in the questing, scientific approach to the subject. These should be combined so that residents consider the assessment and management of all their clinical cases in a critical way, at the same time looking critically also at the pertinent literature. Management and treatment methods should be selected in the context of discussion of the current state of knowledge in the area. Trainees should see and treat children and adolescents of all ages and with the full range of psychiatric disorders. Ten percent of their caseload should consist of mentally retarded children. It may be necessary to teach about some rare syndromes by the use of videotapes. Residents should be familiar with the uses, and drawbacks, of a wide range of therapies, including residential treatment, but can only be expected to develop special expertise in a few. Didactic teaching unrelated to clinical work is probably of limited value.

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