Processing of Biomass Prior to Hydrogen Fermentation and Post-Fermentative Broth Management

Using bioconversion and simultaneous value-added product generation requires purification of the gaseous and the liquid streams before, during, and after the bioconversion process. The effect of diversified process parameters on the efficiency of biohydrogen generation via biological processes is a broad object of research. Biomass-based raw materials are often applied in investigations regarding biohydrogen generation using dark fermentation and photo fermentation microorganisms. The literature lacks information regarding model mixtures of lignocellulose and starch-based biomass, while the research is carried out based on a single type of raw material. The utilization of lignocellulosic and starch biomasses as the substrates for bioconversion processes requires the decomposition of lignocellulosic polymers into hexoses and pentoses. Among the components of lignocelluloses, mainly lignin is responsible for biomass recalcitrance. The natural carbohydrate-lignin shields must be disrupted to enable lignin removal before biomass hydrolysis and fermentation. The matrix of chemical compounds resulting from this kind of pretreatment may significantly affect the efficiency of biotransformation processes. Therefore, the actual state of knowledge on the factors affecting the culture of dark fermentation and photo fermentation microorganisms and their adaptation to fermentation of hydrolysates obtained from biomass requires to be monitored and a state of the art regarding this topic shall become a contribution to the field of bioconversion processes and the management of liquid streams after fermentation. The future research direction should be recognized as striving to simplification of the procedure, applying the assumptions of the circular economy and the responsible generation of liquid and gas streams that can be used and purified without large energy expenditure. The optimization of pre-treatment steps is crucial for the latter stages of the procedure.     

Carbon Dioxide Adsorption over Activated Carbons Produced from Molasses Using H2SO4, H3PO4, HCl,NaOH, and KOH as Activating Agents

Cost-effective activated carbons for CO₂ adsorption were developed from molasses using H₂SO₄, H₃PO₄, HCl, NaOH, and KOH as activating agents. At the temperature of 0 °C and a pressure of 1 bar, CO₂ adsorption equal to 5.18 mmol/g was achieved over activated carbon obtained by KOH activation. The excellent CO₂ adsorption of M-KOH can be attributed to its high microporosity. However, activated carbon prepared using HCl showed quite high CO₂ adsorption while having very low microporosity. The absence of acid species on the surface promotes CO₂ adsorption over M-HCl. The pore size ranges that are important for CO₂ adsorption at different temperatures were estimated. The higher the adsorption temperature, the more crucial smaller pores were. For 1 bar pressure and temperatures of 0, 10, 20, and 30 °C, the most important were pores equal and below: 0.733, 0.733, 0.679, and 0.536 nm, respectively.     

The safer chemical design game. Gamification of green chemistry and safer chemical design concepts for high school and undergraduate students

Green chemistry can strongly attract students to chemistry. We, therefore, developed a green chemistry educational game that motivates students at the undergraduate and advanced high school levels to consider green chemistry and sustainability concerns as they design a hypothetical, chemical product. The game is intended for incorporation into any chemistry course for majors and non-majors that teaches sustainability and/or the Principles of Green Chemistry at the undergraduate level. The game is free of charge and encourages students to think like professional chemical designers and to develop a chemical product with respect to function and improved human and environmental health. This computer simulation has been assessed by educators and can be seamlessly integrated into an existing curriculum.     

Influence of solvent and counter ion on copper complexes with N-alkyl-pyridine-2-carboxamides as studied by electrospray ionization mass spectrometry

The interactions of copper(II) with N-alkyl-pyridine-2-carboxamides (M) were studied by electrospray ionization mass spectrometry. The influence of solvent and counter ion (Cl-, ClO4-) on the type of ions (complexes) observed was discussed. By cone voltage increase, the fragmentation "in source" of the ions discussed was achieved. In methanol solution containing N-alkyl-pyridine-2-carboxamide (M) and CuCl2 the singly- and doubly charged-ions [M+CuCl]+ and [M2+Cu]+2 were detected. In acetonitrile solution containing N-alkyl-pyridine-2-carboxamide and CuCl2, the copper(I)-containing ions [M+CH3CN+Cu]+ were formed. The use of Cu(ClO4)2 instead of CuCl2 resulted in more abundant doubly-charged ions in both methanol and acetonitrlile solutions and, for the former solution, the ions containing methoxyl anion, namely [M+CuOCH3]+, were observed. When water was used as a solvent, the abundant ions corresponding to the protonated ligands were formed, while the ions corresponding to copper complexes were characterised by low abundances.     

Structural properties of transparent Ti-V oxide semiconductor thin films

Transparent oxide semiconducting thin films based on mixed Ti-V oxides were prepared using a modified reactive magnetron sputtering method. Based on structural investigations performed with the help of x-ray diffraction and transmission electron microscopy analysis, two distinct regions in the prepared thin film have been observed: a nanocrystalline TiO₂-V₂O₃-V₂O₅ mixed composition, and a thin layer consisting of amorphous phase and nanocystalline TiO₂ phase deposited directly at the substrate. Optical measurements show excellent transmission in the visible spectral range of 73%, on average. Resistivity of the thin film was found at the order of 10⁵ Ω cm at room temperature. The preparation of mixed Ti-V oxides provides a combination of high transparency and semiconducting properties.     

Hierarchical approach for survivable network design

A central design challenge facing network planners is how to select a cost-effective network configuration that can provide uninterrupted service despite edge failures. In this paper, we study the Survivable Network Design (SND) problem, a core model underlying the design of such resilient networks that incorporates complex cost and connectivity trade-offs. Given an undirected graph with specified edge costs and (integer) connectivity requirements between pairs of nodes, the SND problem seeks the minimum cost set of edges that interconnects each node pair with at least as many edge-disjoint paths as the connectivity requirement of the nodes. We develop a hierarchical approach for solving the problem that integrates ideas from decomposition, tabu search, randomization, and optimization. The approach decomposes the SND problem into two subproblems, Backbone design and Access design, and uses an iterative multi-stage method for solving the SND problem in a hierarchical fashion. Since both subproblems are NP-hard, we develop effective optimization-based tabu search strategies that balance intensification and diversification to identify near-optimal solutions. To initiate this method, we develop two heuristic procedures that can yield good starting points. We test the combined approach on large-scale SND instances, and empirically assess the quality of the solutions vis-à-vis optimal values or lower bounds. On average, our hierarchical solution approach generates solutions within 2.7% of optimality even for very large problems (that cannot be solved using exact methods), and our results demonstrate that the performance of the method is robust for a variety of problems with different size and connectivity characteristics.     

On Stable Equivalence of Tensor Products of Algebras

The paper investigates the following problem. Let bimodules N, M yield a stable equivalence of Morita type between self-injective K-algebras A and E. Further, let bimodules S, T yield a stable equivalence of Morita type between self-injective K-algebras B and F. Then we want to know whether the functor M ? _A  ? ? _B S: mod(A ? _K B ^op ) → mod(E ? _K F ^op ) induces a stable equivalence between A ? _K B ^op and E ? _K F ^op . There is given a reduction of this problem to some smaller subcategories for self-injective algebras. Moreover, new invariants of stable equivalences of Morita type are constructed in a general case of arbitrary finite-dimensional algebras over a field.     

A quantitative thermal analysis of cyclists’ thermo-active base layers

It is well known that clothes used in sporting activity are a barrier for heat exchange between the environment and athlete, which should help in thermoregulation improvement. However, it is difficult to evaluate which top is best for each athlete according to the characteristics of the sport. Researchers have tried to measure the athlete’s temperature distribution during exercise at the base layers of tops with different approaches. The aim of this case study was to investigate the use of thermography for thermo-active base layer evaluation. Six new base layers were measured on one cyclist volunteer during a progressive training on a cycloergometer. As a control condition, the skin temperature of the same volunteer was registered without any layer with the same training. A training protocol was selected approximate to cycling race, which started from the warm-up stage, next the progressive effort until the race finished and at the end “cool-down” stage was over. In order to show which layer provided the strongest and weakest barrier for heat exchange in comparison with environment, the temperature parameters were taken into consideration. The most important parameter in the studies was the temperature difference between the body and the layers, which was changing during the test time. The studies showed a correlation between the ergometer power parameter and the body temperature changes, which has a strong and significant value. Moreover, the mass of every layer was checked before and after the training to evaluate the mass of the sweat exuded during the test. From this data, the layer mass difference parameter was calculated and taken into consideration as a parameter, which may correspond with the mean heart rate value from each training. A high and positive correlation coefficient was obtained between the average heart rate and the mass difference for the base layers. Thermal analysis seems to have a new potential application in the objective assessment of sports clothing and may help in choosing the proper clothes, which could support heat transfer during exercising and protect the body from overheating.

     

Analysis of Fragmentation Pathways of New-Type Synthetic Cannabinoids Using Electrospray Ionization

Recently, dozens of new psychoactive substances have appeared on the European drug market every year. The most abundant group of these compounds is synthetic cannabinoids. In the first few years of the “legal highs” phenomenon, JWH (John W. Huffman) compounds were especially popular among drug users. However, the group of synthetic cannabinoids is constantly expanding, as new compounds are created by replacing known structural elements with different chemical groups. The problem with the identification of novel substances in forensic laboratories results from the structural similarity of the compounds and the rapid introduction of newer designer drugs on the black market. In this study, the fragmentation patterns of 29 new-type synthetic cannabinoids using electrospray ionization were investigated. The analysis was performed using quadrupole time-of-flight mass spectrometry. Based on measurements carried out under various conditions, the way of fragmentation of the tested compounds that were divided into groups due to their chemical structure was established. The study showed that the bond between the carbon atom of the carbonyl group and the ring or NH group attached to the ring was mainly cleaved. This mechanism was adequate for the fragmentation of first-generation synthetic cannabinoids. This paper presents characteristic ions formed by synthetic cannabinoids (i.e., ions originating from an indole/indazole ring and an adamanyl/naphthalene/quinoline ring) using electrospray ionization. Knowledge of these specific fragments can be used in forensic laboratories to determine the structure of novel compounds from the group of synthetic cannabinoids.

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