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We prove that any continuous function can be locally approximated at a fixed point $x_{0}$ by an uncountable family resistant to disruptions by the family of continuous functions for which $x_{0}$ is a fixed point. In that context, we also consider the property of quasicontinuity.

The natural consequence of the existence of different kinds of chaos is the study of their mutual dependence and the relationship between these concepts and the entropy of systems. This observation also applies to the local approach to this issue. In this article, we will focus on this problem in the context of “points focusing chaos.” We aim to show their mutual independence by considering the sets of appropriate periodic dynamical systems in the space of discrete dynamical systems.

In this paper we consider the issues of local entropy for a finite family of generators (that generates the semigroup). Our main aim is to show that any continuous function can be approximated by s-chaotic family of generators.

Arsenic and other heavy metal contaminants in water are a significant global health threat. In this study, low-cost, sulfur-free, sustainable, water-insoluble materials with heavy metal remediation properties were produced from renewable resources such as starch, xylan, citric acid, and chitosan. Synthesized starch citrate-chitosan (SCC) foam and xylan citrate-chitosan (XCC) foam were flexible, porous, and elastic. The foams’ arsenic uptake in water was significantly greater than five different commercial metal remediating agents. The mercury and lead uptakes with the synthesized foams were similar to the performance of a commercial sulfur-based product, SorbaTech 450 (ST450). However, the cadmium and selenium uptakes were comparatively lower. The complexation of arsenic with oxygen and nitrogen of the SCC foam was shown with time-of-flight secondary ion mass spectrometry (TOF-SIMS). The XCC foam was also shown to adsorb potassium iodide (KI) at a similar rate to sodium chloride. This may be used to remediate water contaminated with radioactive materials, such as iodine 131.

The importance of renewable and environmentally friendly wood pulp fibers as an input material for single-use products has grown significantly. However, discarded single-use materials are found in the environment as litter and are sometimes disposed of in wastewater. It is important that these materials are biodegradable and environmentally benign. Wood pulp is mainly comprised of lignocellulosic material, and its composition and structure can vary depending on raw materials and processing, ultimately impacting the biodegradability. In this research, the aquatic biodegradation of five kinds of wood pulp and six different samples of isolated lignocellulosic components (cellulose, hemicellulose, and lignin) have been explored in a consistent detailed manner for the first time, and the effects of chemical composition on the biodegradation discussed. Several lignocellulosic materials were characterized using compositional analysis and were subjected to aquatic biodegradation with bio-solids from a wastewater treatment plant as an inoculum to indicate the potential to biodegrade in the environment. Cellulose and hemicellulose were readily biodegraded over a course of one month. The lignin samples were not biodegradable under these conditions, and the lignin within fibers decreased the biodegradability of the other components of the lignocellulosic fibers. It was also determined that ash and extractives negatively affect the biodegradability. The aerobic aquatic biodegradation results are useful for product designers to select different lignocellulosic materials for applications and for environmental scientists to understand the fate of these fibers in the environment.

The pulp and paper industry is a major source of lignocellulose-containing streams. The components of lignocellulose material are lignin, hemicellulose, and cellulose that may be hydrolyzed into their smaller components and used as feedstocks for valorization efforts. Much of this material is contained in underutilized streams and waste products, such as black liquor, pulp and paper sludge, and wastewater. Bacterial fermentation strategies have suitable potential to upgrade lignocellulosic biomass contained in these streams to value-added chemicals. Bacterial conversion allows for a sustainable and economically feasible approach to valorizing these streams, which can bolster and expand applications of the pulp and paper industry. This review discusses the composition of pulp and paper streams, bacterial isolates from process streams that can be used for lignocellulose biotransformations, and technological approaches for improving valorization efforts. KEY POINTS: • Reviews the conversion of pulp and paper industry waste by bacterial isolates. • Metabolic pathways for the breakdown of lignocellulose components. • Methods for isolating bacteria, determining value-added products, and increasing product yields.

Transforming an innovation into a start-up company can be highly rewarding to the technologist. This editorial considers technology selection for a start-up company. A simple system for screening initial of technologies is given. This editorial is based on years of experience working in translating technologies into start-up companies by the author. These companies have approached their start-up strategies in a variety of different ways. It is important for the technologist to enter into a start-up venture with an understanding of how their technology is positioned both technically and from a business perspective.

The biodegradability of polymers depends on several factors. However, the most critical aspects are the accessibility of the structure for moisture and enzyme diffusion and the capacity of the microbes in the environment to assimilate the final monomers. The accessibility of the polymer structure to enzymes and water depends primarily on crystallinity, hydrophobicity, and the steric effects of the side groups in the polymer backbone. In general, biologically synthesized polymers are readily biodegradable in natural environments but synthetic polymers are either less biodegradable or degrade very slowly. However, such generalizations should be avoided. To understand the compatibility of biomaterials and the environment, both the disintegration step of the biodegradation process and the assimilation and mineralization of these fragments by microorganisms must be investigated. Mineralization occurs when the oligomers and monomers assimilated within the cells are converted to CO2 and H2O (aerobic), and CO2, CH4, and H2O (anaerobic). Although the disintegration of the polymeric structure limits the biodegradation rate and is most easily detected, the final pieces may accumulate in the environment if they are not fully mineralized. Such accumulation could contribute to an issue with microplastics that may be much more difficult to address than the removal of macroscopic, large polymer-based debris.

A comparison between uncreped and creped handsheets was performed to study the effect of fiber morphology and creping process on fiber web structure and tissue properties. Four wood and non-wood pulps refined at different levels were used to manufacture uncreped and creped handsheets using a creping simulator. A characterization of the fiber web structure using scanning electron microscopy (SEM) and evaluation of tissue properties (e.g. tensile strength, water absorbency, softness) was performed on the uncreped and creped handsheets. The results obtained with the creping simulator were compared with commercial products to evaluate the significance of the creping simulator results. The SEM images of the fiber web structure showed that the creping process promoted buckling and distortion of fibers, delamination of surface fiber layer, development of free fiber ends and creation of crepe folds, which enhanced water absorbency and softness at the expense of reduced tensile strength. Short and thin fibers seemed to be more effectively creped than long and coarse fibers. Long and coarse fibers seemed to offer higher resistance to the compressive forces acting at the creping blade. A reasonable correlation between the performance of uncreped and creped handsheets made with different fibers was observed. The results indicate that the performance of uncreped handsheets can be used as a semi-quantitative indication of the performance of creped handsheets. The performance of the creped handsheets were similar to commercial products, which indicates that the creping simulator can be used as an alternative to study the creping process at laboratory scale.

Hemicelluloses, the second most abundant class of biopolymers, have emerged as an immense renewable resource of biopolymers that are recognized as currently being underutilized. Carboxymethyl carbohydrates are valuable products for thickeners, viscosity control, food additive and others. Hemicellulose isolated from poplar was converted to carboxymethyl hemicellulose using sodium chloroacetate (SCA) and sodium hydroxide (NaOH). The significance of the effects of carboxymethylation conditions in an 80% ethanol/water medium on the degree of substitution (DS) and reaction efficiency (RE) was evaluated using a definitive screening design model. There was strong evidence that the dosage of SCA and NaOH, and temperature have a significant effect on DS. A significant interaction between SCA and NaOH was also statistically confirmed. The RE resulting from the ethanol/water medium was lower than 50%. A higher RE of 72% with a DS 1.08 was achieved in a 90% tert-butyl alcohol/water medium, which was conducted at 85 °C with 120 min, 1.5 mol/mol anhydroxylose unit (AXU) of NaOH and 1.5 mol/mol AXU of SCA. The potential of using hemicellulose and carboxymethyl hemicellulose as materials to produce water-soluble films was evaluated. Due to the increased water solubility, the processing of carboxymethyl hemicellulose in water and the production of films were more facile than with unmodified hemicellulose. All of the films demonstrated significant oxygen barrier characteristics, with low oxygen permeability ranging from 0.28 to 0.55 cm3 µm/(m2 d kPa). The films did not display effective water vapor barrier characteristics, with high water vapor permeability ranging from 4.8 to 6.5 g mm/(m2 d kPa). Carboxymethylation of HC decreased the tensile strength, increased the elongation at break, and decreased the water vapor and oxygen barrier properties of the produced films. Both hemicellulose and carboxymethyl hemicellulose films could offer a bio-based and biodegradable alternative to existing synthetic oxygen barrier materials. The hemicellulose and carboxymethyl hemicellulose materials might be exploited in water-soluble films, washable fruit coating or used in composites or multilayer films in conjunction with hydrophobic layers.

Linting and dusting are commonly used terms to describe the tendency of a tissue web to release unbound and loosely bound fibers or filler particles during the tissue-making process or in the finished tissue product. Lint/dust generation has an overall negative impact across tissue paper manufacturing and handling operations, causing safety hazards, machine runnability difficulties, and product quality issues. To date, there are no well-established industry standards to quantify dusting/linting propensities in finished tissue products, thus evaluating the effectiveness of dust/lint control programs is challenging yet intriguing. This research aims to fill this gap by developing a methodology to characterize dusting in tissue papers. We have developed a device prototype (named the Tissue Dust Collector) and a methodology that together have been named the Tissue Dust Analysis System (TDAS), which aims at quantifying the propensity for tissue-grade paper products to generate dust/lint in a controlled and reproducible manner. Two samples, corresponding to commercial products with a low and high linting propensity, were tested using the proposed device and methodology, and the released particles were quantified and characterized. The device and methodology provided reproducible results for simulated consumer handling and product manufacturing scenarios. By changing the instrument's motor frequency, the force of agitation changes, mimicking/simulating consumer (60 strokes per min, spm) and producer/manufacturing (180 spm) handling scenarios (though manufacturing processes are much faster in practice). Particle counts at each level for each product showed reproducible values differentiable at different agitation levels. Adopting the proposed Tissue Dust Analysis System may help to collect, characterize and understand the mechanisms behind dusting to alleviate this issue at its various sources through dust-control strategies.

Nonwoven products are widely used in disposable products, such as wipes, diapers, and masks. Microfibers shed from these products in the aquatic and air environment have not been fully described. In the present study, 15 commercial single-use nonwoven products (wipes) and 16 meltblown nonwoven materials produced in a pilot plant were investigated regarding their microfiber generation in aquatic and air environments and compared to selected textile materials and paper tissue materials. Microfibers shed in water were studied using a Launder Ometer equipment (1-65 mg of microfibers per gram material), and microfibers shed in air were evaluated using a dusting testing machine that shakes a piece of the nonwoven back and forth (~ 4 mg of microfibers per gram material). The raw materials and bonding technologies affected the microfiber generation both in water and air conditions. When the commercial nonwovens contained less natural cellulosic fibers, less microfibers were generated. Bonding with hydroentangling and/or double bonding by two different bonding methods could improve the resistance to microfiber generation. Meltblown nonwoven fabrics generated fewer microfibers compared to the other commercial nonwovens studied here, and the manufacturing factors, such as DCD (die-to-collector distance) and air flow rate, affected the tendency of microfiber generation. The results suggest that it is possible to control the tendency of microfiber shedding through the choice of operating parameters during nonwoven manufacturing processes.

A comparison among ten market pulps at a laboratory scale using uncreped tissue handsheets was performed to study the performance of wood and non-wood pulps for tissue manufacturing, evaluate what fiber features are desired for a specific tissue property, and determine how non-wood pulps can be used to replace or complement wood pulps in tissue products. A characterization of the fiber morphology and handsheet properties (softness, water absorbency, and strength) was performed at different mechanical refining levels. The results showed that the fiber morphology had a major impact on tissue properties. Market pulps with a combination of long fibers, high coarseness, and low fines content can provide superior bulk and water absorbency. Short fibers with thin cell walls and low fines content can impart superior softness. Bleached bamboo soda pulp can replace hardwood and softwood pulps to provide an excellent combination of water absorbency and strength. Bleached bamboo soda pulp can also replace Northern bleached softwood kraft (NBSK) pulp to impart strength without sacrificing softness. Bleached and semi-bleached wheat straw soda pulps presented a similar combination of softness and strength as Southern bleached hardwood kraft (SBHK) pulp. The wheat straw pulps can be used to replace deinked pulp (DIP) pulp to impart intermediate levels of water absorbency and strength.

A rapid and green preparation of lignin nanoparticles was demonstrated starting from bio-refinery lignin containing grafted carbohydrates. The particles were prepared by recovering a fraction of the lignin, which contained 24% carbohydrate (by weight) as the insoluble fraction in 0.5 M NaOH. The carbohydrate content of this fraction was verified with a wet chemistry analytical technique, nuclear magnetic resonance, and X-ray diffraction. This fraction was then dissolved in a NaOH/urea/water system and added dropwise to water under a high shear, which rapidly formed precipitated particles in a size range of approximately 100 nm. This carbohydrate-containing fraction of the lignin was soluble in a green solvent system that was not suited for lignin alone. The generated particles were stable in different organic solvents and water. Overall, the dissolution of the bio-refinery lignin in the NaOH/urea/water system, followed by precipitation in water can be regarded as a green and rapid method to produce stable nanoparticles. The generated nanoparticles, containing both carbohydrates and lignin, are expected to have unique applications because of their bi-component nature. Furthermore, this is the first publication to show how materials with high levels of lignin can be solubilized in solvents that are conventionally used for cellulose.

We present a method derived from Mott and Davies or Cody equation for calculating energy gap based on spectrophotometric measurements. The method has been tested on thin film TiO2 and MoS2/TiO2 bilayer produced by RF magnetron sputtering. The presented examples indicate that the Tauc and McLean methods, which are usually used to analyse data, are not justified in many cases, especially for multilayers. In the Tauc method, the problem is to determine the energy gap without knowing the nature of the optical transition. The McLean method involves fitting the power function which may cause difficulties in the proper selection of the fitting range. The presented method is based on the transformation of measurement data using inverse logarithmic derivative and performing of linear fittings. Our method does not assume value of the parameter m describing the nature of the optical transition and does not require knowledge of the thickness of the layers. The value of energy gap and parameter m can be obtained simultaneously thanks to one linear fit. In addition, this method has a practical advantages over methods of McLean and Tauc, which are described in the article.

We analyse local aspects of chaos for nonautonomous periodic dynamical systems in the context of generating autonomous dynamical systems and the possibility of disturbing them.

The extractability of hemicellulose from different lignocellulosics depends on the source of biomass. Differences in hemicellulose extractability are believed to be due to plant-specific hemicellulose arrangement alongside lignin within the cell wall. In this research, six biomasses were used to probe hemicellulose alkaline extractability as a function of the native lignin within the biomasses. Quantitative 2D-HSQC and 13C NMR analysis were performed to determine the S/G (S: syringyl, G: guaiacyl) and lignin-carbohydrate complex (LCC) linkages of milled wood lignin isolated from these biomasses. A strong negative correlation was observed between total lignin content and hemicellulose extractability, demonstrating that a greater presence of lignin in the original material results in lower xylan solubilization. In addition, a correlation between S/G of lignin and xylan dissolution was found within a group of hardwoods and within a group of non-woods. This suggests that monomeric constituency also influences xylan’s propensity for dissolution in 10% NaOH. Although there is some uncertainty in the quantification of LCC linkages, both non-woods and hardwoods exhibited negative correlations between alkaline-stable LCC linkages content and xylan extractability. This suggests that alkaline-stable LCC structures are associated with a decrease in the alkaline extractability of hemicellulose.

This work presents, for the first time, a package- level, bare die liquid jet impingement 3D polymer microfluidics heatsink fabricated using 3D printing, or additive manufacturing for large die size and high-power applications. The heatsink achieves a chip temperature increase of 17.5°C at a chip power of 285 W for a coolant flow rate of 3.25 LPM, demonstrating that 3D printing enables the design for low-cost, high efficiency direct on-chip microfluidic heatsink with complex internal 3D manifold liquid delivery channels. The measurement results show that the jet impingement cooling performance can be successfully described using a unit cell approach, allowing an easy scaling of the thermal performance for arbitrary die size applications. Long term thermal tests of 1000h show a constant thermal performance and no degradation of the cooler material.

Softness, as a subjective perception, is difficult to define and quantify. For decades, panel tests have been used to judge differences in the softness of hygiene tissue samples. Panel tests can be a time-consuming and expensive process. A number of protocols have been developed to quantify the physical properties of tissues associated with softness. The Tissue Softness Analyzer (TSA) by Emtec has gained popularity in characterizing the physical properties of tissues associated with softness. The instrument was designed with softness in mind and attempts to simulate the touch of the human hand. There is currently no comprehensive study that compares the results from a TSA and human panel. In this work, panel tests were used to validate the performance of the TSA with bath tissue. It was determined that one component of the TSA measurements (TS7) linearly correlated with the panel results. Among all of the algorithms available for use with the TSA, the TP2 algorithm most accurately predicted the panel scores. The TSA performed better in predicting the softness of the samples that were dried with a conventional wet press or creped-through air-dryer.

This study aimed to identify the performance properties that drive the shelf price of kitchen paper towels and evaluate whether sustainability is an important driver for pricing. Nineteen products were compared according to their performance (softness, absorbency, and strength), technology, and fiber morphology. Metrics to rank the products in different grades (economy, premium, and ultra) according to their performance were provided. A multiple linear regression showed that absorbency and softness are the most significant properties used to predict the price. Market data indicates that there is a segment of consumers willing to pay a premium price for products marketed as “sustainable”, even though their performance is comparatively inferior to the majority of the samples. Sustainable products are up to 85% more expensive than regular products. The metrics obtained in this work can contribute to improvement in market transparency, and aid companies in deciding strategies for product development and new investments.

We introduce the concept of a peculiar point (of the first and second kind), which combines stability of functions around a given point on a large set in the sense of Lebesgue measure with strong chaos of a function (in the sense of its entropy value) around this point. We prove that almost continuity of a function is equivalent to the fact that in every $$\Gamma $$ -neighbourhood of this function one can find a continuous function having a peculiar point either of the first or second kind.

Hemicellulose is an abundant and underutilized carbohydrate polymer in plants. The objective of this study was to understand the effect of delignification on hemicellulose extraction efficiency with different types of lignocellulosic biomass. In the case of pine, with a prior sodium chlorite or peracetic acid delignification, more than 50% of the original hemicellulose in the biomass could be extracted using a 10% sodium hydroxide solution; without delignification, only 3.4% of hemicellulose could be extracted from pine. In contrast, without prior delignification, acceptable hemicellulose extraction efficiencies (55.5% and 50.7%, respectively) were achieved from switchgrass and poplar. In addition, the effect of hemicellulose extraction processes on the enzymatic convertibility of the cellulose-rich residues after extraction was determined. The cellulose-rich residues from switchgrass after hemicellulose alkali extraction showed high glucose recovery with enzyme hydrolysis with or without prior delignification. For pine and poplar, high glucose recovery with enzyme hydrolysis of the cellulose-rich residues only occurred if the sample had a delignification step prior to hemicellulose extraction. This information on commercially available biomass feedstocks is useful for those considering isolating hemicellulose within a biorefinery concept.

The aim of the paper is to examine topological properties of disruptions of nonautonomous discrete dynamical system by other “close” systems. Our considerations will be connected with entropy of a system at a point and with stable points of a system.

We examine dynamical systems which are ‘nonchaotic’ on a big (in the sense of Lebesgue measure) set in each neighbourhood of a fixed point $x_{0}$, that is, the entropy of this system is zero on a set for which $x_{0}$ is a density point. Considerations connected with this family of functions are linked with functions attracting positive entropy at $x_{0}$, that is, each mapping sufficiently close to the function has positive entropy on each neighbourhood of $x_{0}$.

We consider stable and almost stable points of autonomous and nonautonomous discrete dynamical systems defined on the closed unit interval. Our considerations are associated with chaos theory by adding an additional assumption that an entropy of a function at a given point is infinite.

We present magnetic and electrical transport properties such as resistivity, magnetoresistance, dielectric, and polarization of polycrystalline ${\mathrm{YbFe}}_{2}{\mathrm{O}}_{4}$. The ferrimagnetic transition temperature is measured at 243 K, followed by the two low-temperature transitions at $\ensuremath{\sim}190$ and $\ensuremath{\sim}65$ K, respectively. The magnetic properties including the $M\ensuremath{-}H$ hysteresis loops exhibit a strong temperature dependence and possibly indicate a spin-glass state below 65 K for ${\mathrm{YbFe}}_{2}{\mathrm{O}}_{4}$. The iron M\"ossbauer measurement at 295 K confirms the presence of two Fe sites. The measured resistivity can be modeled with the Mott's variable-range hopping model, $\ensuremath{\rho}\ensuremath{\propto}exp{({T}_{0}/T)}^{1/4}$, indicating the electron hopping between ${\mathrm{Fe}}^{2+}$ and ${\mathrm{Fe}}^{3+}$ sites. The magnetoresistance effects up to 6% at 8 T were observed and the effects could be caused by the field-induced changes in the electron-hopping processes. The frequency-dependent complex dielectric constant has been found to be strongly influenced by the contact effects, and the polarization of polycrystalline ${\mathrm{YbFe}}_{2}{\mathrm{O}}_{4}$ does not show ferroelectricity.

In this paper, the notion of a distributionally chaotic point (connected with focusing of an uncountable distributionally scrambled set and its envelope around this point) is introduced. The theorems dealing with the existence of such points for selfmaps of the closed unit interval and the possibilities of approximation of nonautonomous discrete dynamical systems by systems with i-stable and p-DC1 points are proved.

The presence and biodegradability of textile microfibers shed during laundering or use is an important environmental issue. In this research, the influence of common textile finishes on the persistence of cotton fibers in an aerobic aquatic environment was assessed. The biodegradation of cotton knitted fabrics with different finishes, silicone softener, durable press, water repellent, and a blue reactive dye was evaluated. The rate of biodegradation decreased with durable press and water repellant finishing treatments. In terms of the final extent of biodegradation, there was no significant difference between the samples. All samples reached more than 60% biodegradation in 102 days. The biodegradation rates were in agreement with observed trends of the same samples for cellulase mediated hydrolysis and cellulase adsorption experiments, indicating the finishes impact the initial adsorption of enzymes excreted by the microorganisms and the initial rates of biodegradation, however despite this the cellulosic material maintains its biodegradability.