Copolymers of glycerol and propylene glycol diglycidyl ethers with aromatic dithiols

Monomers derived from renewable recourses have the potential to become the biobased alternatives for petroleum derived chemicals in the production of polymers. Glycerol, the byproduct of biodiesel refining, and propylene glycol derived from glycerol are promising candidates which can be used in the synthesis of polymers as they are or after chemical modification. The new copolymers of glycerol and propylene glycol diglycidyl ethers with aromatic dithiols were synthesized and investigated in this study. Their chemical structures were confirmed by IR, ¹H‐NMR spectroscopy, and gel permeation chromatography. The dependencies of the mechanical, thermal properties, swelling in the different solvents, biodegradability, and bioresistance of synthesized copolymers on their chemical structures were studied. The properties of some synthesized copolymer films were found to be comparable with those of commodity polymer films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4367–4374, 2013     

Charge-transporting 3,4-ethylenedioxythiophene-based hydrazone monomers and oligomers

3,4-Ethylenedioxythiophene-based hydrazones, containing reactive functional groups were synthesized and their optical, thermal, photophysical and electrochemical properties were studied. The monomers were subjected to cationic polymerization using boron trifluoride etherate as an initiator. The ionization potentials of the films of the hydrazones, measured by the electron photoemission technique, range from 5.53 to 5.62 eV. Room temperature time-of-flight hole mobilities in the solid solutions of 3,4-ethylenedioxythiophene hydrazone monomers in bisphenol-Z polycarbonate exceed 10^?5 cm² V^?1 s^?1 at high applied electric fields.     

Situational method engineering: combining assembly-based and roadmap-driven approaches

Because the engineering situation of each information system development (ISD) project is different, engineering methods need to be adapted, transformed or enhanced to satisfy the specific project situation. Contributions, in the field of situational method engineering (SME), aim at providing techniques and tools allowing to construct project-specific methods instead of looking for universally applicable ones. In addition to the engineering method tailoring, necessary to fit the project situation, a customization of the engineering method for each engineer participating in the project is also required. Such a configuration allows a better understanding of the method by focusing on guidelines related to the project engineer’s daily tasks. It also increases his/her involvement in the ISD method realization. To achieve this twofold objective (ISD method tailoring and customization), we propose a framework for SME combining an assembly-based approach for project-specific method construction and a roadmap-driven approach for engineer-specific method configuration. The first step of our process provides support to build a new method that is most suitable for the current ISD project situation, whereas the second step aims at choosing the most adapted path (roadmap) to satisfy the requirements of a particular project engineer within the project-specific method. The two core elements of our SME framework are the method chunks repository and the reuse frame. The former concerns reusable method components definition and storage whereas the latter deals with the characterization of the project situation and the project engineer’s profile. In this paper we start first by presenting our SME framework and its core elements: the method chunk repository and the reuse frame. Then we show how to take advantage of them through our two-step process combining assembly-based method construction and roadmap-driven method configuration.     

Synthesis and properties of photocross‐linked polymers of epoxidized linseed oil with different reactive diluents

Cross‐linked polymers were obtained by photopolymerization of epoxidized linseed oil with different reactive diluents (3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexane carboxylate, 1,4‐cyclohexane dimethanol diglycidyl ether, bisphenol A diglycidyl ether, trimethylolpropane triglycidyl ether, and bis[4‐(glycidyloxy)phenyl]methane) using the mixture of triarylsulfonium hexafluoroantimonates as photoinitiator. The kinetic of photocross‐linking reactions of compositions with different concentrations of reactive diluents was investigated. The 69%–91% conversion of epoxy groups of the compositions containing reactive diluents was reached. The mechanical properties, thermal stability, and swelling in polar and nonpolar solvents of the photocross‐linked polymers were studied. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Glass-forming hole-transporting carbazole-based hydrazone monomers,polymers, and twin compounds

The synthesis, optical, thermal, and photoelectrical properties of new carbazole-based hydrazone monomers, polymers, and twin compounds are reported. All the synthesized materials are capable of glass formation. Their glass transition temperatures range from 27 to 90 °C. The ionization potentials of the films of carbazole-based hydrazones measured by the electron photoemission technique range from 5.18 to 5.48 eV. Hole-drift mobilities in the amorphous films of the synthesized hydrazone monomers measured by the time-of-flight technique at room temperature reach 10^?4 cm²/(V s) at high applied electric fields.     

Photocross-linked polymers based on plant-derived monomers for potential application in optical 3D printing

Photocross linking of the resins composed of plant-derived monomers, acrylated epoxidized soybean oil (AESO), myrcene (MYR) and vanillin dimethacrylate (VDM) or divinylbenzene (DVB, for comparison), was performed using 2,2-dimethoxy-2-phenylacetophenone as photoinitiator. Photocross-linking rate and properties of the crosslinked polymers depended on the resin compositions. The higher amount of MYR caused not only the better homogenization and lower viscosity of the resin but also the reduction of polymerization rate and the worse mechanical and thermal properties of the resulting polymers. The higher amount of aromatic component (VDM or DVB) improved mechanical and thermal properties of polymers. Moreover, the use of VDM instead of DVB in the system led to the higher photocross-linking rate and higher yield of insoluble fraction. The resin composed of only plant-derived monomers AESO/MYR/VDM, molar ratio 1:1:3, showed characteristics comparable to those of commercial petroleum-derived photoresins and was selected as a potential renewable photoresin for application in optical 3D printing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48708.     

Evaluation of the use of lactic acid bacteria and Thymus vulgaris essential oil on Suffolk and Ile de France lamb breed (MuscuIus gluteus) quality parameters

In the present study, Lactobacillus plantarum (LUHS135), Thymus vulgaris essential oil (0.1% v/v) and their combination were used to treat Suffolk and Ile de France lamb meat. Changes in the microbiological profile and physicochemical parameters of meat were evaluated after 24 h of treatment at 4 °C. Treatments resulted in significantly lower mould/yeast, total enterobacteria (by up to 45%) counts, water-holding capacity (by 21–63%) and cooking loss (by 17–35%) in all samples. Moisture content increased, on average, by 14.5% in the Suffolk meat. Polyunsaturated fatty acid content increased after all treatments. Treatments and breed significantly affected the content of malondialdehyde and some biogenic amines. Sensory analysis showed that raw lamb meat colour was more acceptable after all treatments, while the odour acceptability was ranked highest after combined treatment. These findings suggest that the applied treatments could be used to improve microbiological safety and some quality characteristics and to increase the PUFA content of lamb meat.     

Novel hole-transporting carbazole main chain oligomer and its model glass-forming compound

Summary The oligomer containing 9-[2-(9H-carbazo1-9-yl)cyclobutyl]-9H-carbazole moiety in the main chain and its model compound were synthesized by Wittig reaction. Both compounds form glasses with glass transition temperatures of 254°C and 135°C respectively. The optical and photoelectrical properlies of the compounds were studied. The hole drift mobilities observed in the film of the oligoiner by the time of flight technique were in the range of 2·10⁻⁶ – 7·10⁻⁶ cm²/(V·s) at an applied electric field ranging from 5·8.10⁴ to 2·7.10⁵ V/cm. Rcceivcd: 3 April 2002/Revised version: 16 July 2002/ Accepted: 5 August 2002 Correspondence to Juozas V. Grazulevicius e-mail: juogra@ctf.ktu.lt. Tel/Fax: +37 07 456525     

Attention-Based and Time Series Models for Short-Term Forecasting of COVID-19 Spread

The growing number of COVID-19 cases puts pressure on healthcare services and public institutions worldwide. The pandemic has brought much uncertainty to the global economy and the situation in general. Forecasting methods and modeling techniques are important tools for governments to manage critical situations caused by pandemics, which have negative impact on public health. The main purpose of this study is to obtain short-term forecasts of disease epidemiology that could be useful for policymakers and public institutions to make necessary short-term decisions. To evaluate the effectiveness of the proposed attention-based method combining certain data mining algorithms and the classical ARIMA model for short-term forecasts, data on the spread of the COVID-19 virus in Lithuania is used, the forecasts of epidemic dynamics were examined, and the results were presented in the study. Nevertheless, the approach presented might be applied to any country and other pandemic situations. The COVID-19 outbreak started at different times in different countries, hence some countries have a longer history of the disease with more historical data than others. The paper proposes a novel approach to data registration and machine learning-based analysis using data from attention-based countries for forecast validation to predict trends of the spread of COVID-19 and assess risks.