Effect of the size of the charged group on the properties of alkoxylated NFCs

The impact of the size of the charged group on the properties of alkoxylated NFC was studied by two chloroalkyl acid reagents. It was found that the employment of the larger 2-chloropropionic acid reagent leads to improved properties, e.g. higher fraction of nano-sized materials, and significantly better redispersion as compared to when the smaller monochloroacetic acid was employed. The differences in the impacts of the different reagents were hypothesized to be due to a more efficient disruption of the cohesion between the nanofibrils when a larger charged group was employed.     

Radon’s construction and matrix relations generating syzygies

Monatshefte für Mathematik - Let $$\varPi _n$$ be the set of bivariate polynomials of degree not greater than n. A $$\varPi _n$$-correct set of nodes is a set such that the Lagrange...     

Application of a primarily deductive framework describing time consumption for hauling of logs to road-side

Forest management planning decisions are often based on the forest owner’s goals, which typically focus on economic criteria. Logging operation work productivity functions are used when costing forest operations. These functions affect the conclusions drawn during forest management analyses because different logging environments give rise to different harvesting costs. When evaluating new combinations of machines and environments, there is generally a shortage of field data on productivity that can be examined in advance. We applied a previously published deductive framework describing time consumption in forwarding to known environments, in which field studies on forwarding have been conducted and for which extensive data are available. We then adapted the deductive framework to better reproduce the results obtained in the time studies. The deductive framework accurately reproduced the observed forwarding productivities; on average, the adaptation process improved the accuracy of this reproduction. However, it may also have reduced the accuracy of individual predictions. We conclude that the deductive framework can be used as a basis for constructing work productivity functions for forest management analyses, and can serve as a foundation when constructing new productivity functions based on time study results to use when pricing forwarding.     

Probing Supramolecular Interactions between a Crown Ether Appended Zinc Phthalocyanine and an Ammonium Group Appended to a C60 Derivative

Self‐assembly driven by crown ether complexation of zinc phthalocyanines equipped with one 18‐crown‐6 moiety and fullerenes bearing an ammonium head group afforded a novel donor–acceptor hybrid. In reference experiments, fullerenes containing a Boc‐protected amine functionality have been probed. The circumvention of zinc phthalocyanine aggregation is important for the self‐assembly, which required the addition of pyridine. From absorption and fluorescence titration assays, which provided sound and unambiguous evidence for mutual interactions between the electron donor and the electron acceptor within the hybrids, association constants in the order of 8.0×10⁵ m ^?1 have been derived. The aforementioned is based on 1:1 stoichiometries, which have been independently confirmed by Job's plot measurements. In the excited state, which has been examined by transient absorption experiments, intermolecular charge separation evolves from the photoexcited zinc phthalocyanine to the fullerene subunit and leads to short‐lived charge‐separated states. Interestingly, photoexcitation of zinc phthalocyanine dimers/aggregates can also be followed by an intermolecular charge separation between vicinal phthalocyanines. These multicomponent supramolecular ensembles have also been shown by in‐depth electrospray ionization mass spectrometry (ESI‐MS) studies, giving rise to the formation and detection of a variety of non‐covalently linked species.     

Derivatives of benzo[b]furan. Part I. Conformational studies of khellinone and visnaginone

Structural Chemistry - The structural analysis of khellinone and visnaginone indicated the planarity of the benzo[b]furan ring system. The oxygen or carbon atoms of the substituents, –OH,...     

The Influence of Substituent Orientation on the Photovoltaic Performance of Phthalocyanine‐Sensitized Solar Cells

Phthalocyanines (Pcs) are used as sensitizers in dye‐sensitized solar cells (DSSCs) because of their stability and intense absorption in the red and near‐IR regions. Impressive progress has been made in photovoltaic efficiencies by introduction of bulky peripheral substituents to help suppress macrocycle aggregation. To reach benchmark efficiencies reported for other related dyes, new designs need to be explored. Single carboxy‐ZnPc regioisomers substituted at the non‐peripheral positions by rigid aryl groups have now been studied, which has shed light on the influence of steric hindrance and/or orientation of the substituent around the anchoring group on the photovoltaic response. The regioisomer bearing the aryl group far away from the anchoring group produces a more effective sensitization of the TiO₂ films and higher short‐circuit photocurrent density (J_sc). Taking advantage of the good photovoltaic performance in the near‐IR region of this ZnPc, it was combined with another appropriate dye for panchromatic sensitization of the mesoporous photoelectrode and an increase of the overall device efficiency.     

Emissions and deposit properties from combustion of wood pellet with magnesium additives

This work studies the amount of gaseous and particle emissions and deposits on heat exchanger surfaces in a boiler firedwith commercially available pellets and with pellets primed with magnesium oxide and magnesium hydroxide.The combustionexperiments were performed on a residential boiler of 20 kW.Substrates placed in the heat exchanger was analysed with SEM-EDX-mapping to evaluate the chemical composition of the deposits.The results show that particle emissions(PM 2.5)using the additivesincreased by about 50%and the mass of the deposits in the flue gas heat exchanger(excluding loose fly ash)increased by about25%compared to the combustion of pellets without additives.The amount of additives was found to be eight times higher than theamount of the main alkali metals potassium(K)and sodium(Na)which leads to the assumption that the additives were overdosedand therefore caused the problems reported.The SEM analysis of the substrates placed in the flue gas heat exchanger indicate that thedeposits of sodium(Na),potassium(K),chlorine(Cl)and sulphur(S)decrease using the additives.If this was due to theexpected chemical reactions or due to the loose fly ash covering the substrates after the test,could not be determined in this study.     

Modification of crystallinity and pore size distribution in coagulated cellulose films

In this study the effects of altering the coagulation medium during regeneration of cellulose dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate, were investigated using solid-state NMR spectroscopy and NMR cryoporometry. In addition, the influence of drying procedure on the structure of regenerated cellulose was studied. Complete conversion of the starting material into regenerated cellulose was seen regardless of the choice of coagulation medium. Coagulation in water predominantly formed cellulose II, whereas coagulation in alcohols mainly generated non-crystalline structures. Subsequent drying of the regenerated cellulose films, induced hornification effects in the form of irreversible aggregation. This was indicated by solid-state NMR as an increase in signal intensity originating from crystalline structures accompanied by a decrease of signal intensity originating from cellulose surfaces. This phenomenon was observed for all used coagulants in this study, but to various degrees with regard to the polarity of the coagulant. From NMR cryoporometry, it was concluded that drying induced hornification generates an increase of nano-sized pores. A bimodal pore size distribution with pore radius maxima of a few nanometers was observed, and this pattern increased as a function of drying. Additionally, cyclic drying and rewetting generated a narrow monomodal pore size pattern. This study implies that the porosity and crystallinity of regenerated cellulose can be manipulated by the choice of drying condition.     

Doxorubicin Encapsulation Investigated by Capillary Electrophoresis with Laser-Induced Fluorescence Detection

Doxorubicin (DOX) belongs to the group of anthracycline antibiotics with very effective anticancer properties. On the other hand, the cardiotoxic effects limit its application over the maximum cumulative dose. To overcome this obstacle, encapsulation of this drug into the protective nanotransporter such as apoferritin is beneficial. In this study, fluorescent behavior of DOX in various solvents was determined by fluorescence spectrometry, demonstrating the fluorescence quenching effect of water, which is often used as a solvent. It was found that by increasing the amount of the organic phase in the DOX solvent the dynamic quenching is significantly suppressed. Ethanol, acetonitrile and dimethyl sulfoxide were tested and the best linearity of the calibration curve was obtained when above 50 % of the solvent was present in the binary mixture with water. Moreover, pH influence on the DOX fluorescence was also observed within the range of 4–10. Two times higher fluorescence intensity was observed at pH 4 compared to pH 10. Further, the DOX behavior in capillary electrophoresis (CE) was investigated. Electrophoretic mobilities (CE) in various pH of the background electrolyte were determined within the range from 16.3 to −13.3 × 10 ⁻⁹ m⁻² V⁻¹ s⁻¹. Finally, CE was also used to monitor the encapsulation of DOX into the cavity of apoferritin as well as the pH-triggered release.