Thermal properties of flame retardant viscose fibers

This paper discusses the problem of the thermal properties of flame retarding additives based on phosphazene derivatives and of the commercial agents TomflamB, FlammexT23P and StockhausenW-20949, as well as of flame resistant viscose fibers containing the above agents. Results of this investigation showed the action of FlammexT23P, StockhausenW-20949 and phosphazene derivatives at lower temperature. TomflamB acted within a much wider range of temperatures. The flame retardant additives applied to viscose fibers change the thermal properties of the fiber material.     

Photoelectrochemical Properties of Annealed Anodic TiO2 Layers Covered with CuOx

In this work, we present a systematic study on the influence of Cu²⁺ ion concentration in the impregnation solution on the morphology, structure, optical, semiconducting, and photoelectrochemical properties of anodic CuO_x-TiO₂ materials. Studied materials were prepared by immersion in solutions with different concentrations of (CH₃COO)₂Cu and subjected to air-annealing at 400 °C, 500 °C, or 600 °C for 2 h. The complex characterization of all studied samples was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), reflectance measurements, Mott–Schottky analyses, and photocurrent measurements. It was found that band gap engineering based on coupling CuO with TiO₂ (E_g~3.3 eV) is an effective strategy to increase the absorption in visible light due to band gap narrowing (CuO_x-TiO₂ materials had E_g~2.4 eV). Although the photoactivity of CuO-TiO₂ materials decreased in the UV range due to the deposition of CuO on the TiO₂ surface, in the Vis range increased up to 600 nm at the same time.     

Classification of Polish Natural Bee Honeys Based on Their Chemical Composition

The targeted quantitative NMR (qNMR) approach is a powerful analytical tool, which can be applied to classify and/or determine the authenticity of honey samples. In our study, this technique was used to determine the chemical profiles of different types of Polish honey samples, featured by variable contents of main sugars, free amino acids, and 5-(hydroxymethyl)furfural. One-way analysis of variance (ANOVA) was performed on concentrations of selected compounds to determine significant differences in their levels between all types of honey. For pattern recognition, principal component analysis (PCA) was conducted and good separations between all honey samples were obtained. The results of present studies allow the differentiation of honey samples based on the content of sucrose, glucose, and fructose, as well as amino acids such as tyrosine, phenylalanine, proline, and alanine. Our results indicated that the combination of qNMR with chemometric analysis may serve as a supplementary tool in specifying honeys.     

High energy,large momentum transfer amplitudes: The sum of ladder diagrams inΦ 3 theory

We perform summation of ladder diagrams in the high energy, large momentum limit. This leads to new results for both perturbative and non-perturbative approaches. In particular, an explicit expression for any diagram's contribution is given, the non-perturbative form of asymptotically non-analytic terms is found and representation of amplitude as a series of Regge poles is presented.Supported in part by Polish Ministery of National Education, grant no. CPBP 01.03     

The plasticity of the Cu(H2O) 6 2+ Jahn-Teller complex affected by lattice strains and cooperative interactions

The EPR spectra evolution of Cs₂Zn_1?x Cu_x(ZrF₆)₂ · 6H₂O (x=0.01, 0.6, 0.8, and 1.0) in the temperature range 4.2–330 K and the x-ray structure analysis of the compound with x=1.0 in the range 150–327 K show that the Jahn-Teller (JT) complex Cu(H₂O)₆ coordination sphere undergoes a plastic deformation. The observed effect is due to the combined influence of small lattice strains existing in the paraphase and a new one appearing as a result of a ferroelastic phase transition and increasing with decreasing temperature below T _c . It is proved that both cooperative interactions between JT complexes and ferroelastic strain stabilize a certain JT configuration. The problem of instability of a JT configuration compressed at T ～ 265 K is discussed.     

Real-World Data Difficulty Estimation with the Use of Entropy

In the era of the Internet of Things and big data, we are faced with the management of a flood of information. The complexity and amount of data presented to the decision-maker are enormous, and existing methods often fail to derive nonredundant information quickly. Thus, the selection of the most satisfactory set of solutions is often a struggle. This article investigates the possibilities of using the entropy measure as an indicator of data difficulty. To do so, we focus on real-world data covering various fields related to markets (the real estate market and financial markets), sports data, fake news data, and more. The problem is twofold: First, since we deal with unprocessed, inconsistent data, it is necessary to perform additional preprocessing. Therefore, the second step of our research is using the entropy-based measure to capture the nonredundant, noncorrelated core information from the data. Research is conducted using well-known algorithms from the classification domain to investigate the quality of solutions derived based on initial preprocessing and the information indicated by the entropy measure. Eventually, the best 25% (in the sense of entropy measure) attributes are selected to perform the whole classification procedure once again, and the results are compared.     

Photothermally Induced Bistability of Emission of Yb-doped Ca4NdO(BO3)3 Single Crystals

We report on studies of changes in the emission spectra (excited at 808 nm) of the Yb-doped Ca₄NdO(BO₃)₃ single crystals due to the photothermal effects caused by the pulsed Nd:YAG laser. Increase of the sample's surface temperature after laser treatment leads to significant enhancement of the 1040 to 1060 nm emission (ascribed to the Nd^{3+ 4}F_3/2 → ⁴I_9/2, ⁴I_11/2 transitions) and simultaneous decrease of the 975 to 1050 nm emission (corresponding to the Yb^{3+ 2}F_5/2 → ²F_7/2 transition). We explain such an increase of the Nd³⁺ luminescence by thermally activated Yb³⁺ → Nd³⁺ energy transfer.     

Statistical approach to multiple-q modulated structures: average Patterson analysis

Using a statistical approach, the average unit cells have been constructed for modulated structures with different types of modulation, from simple sinusoidal to square-wave functions. The obtained unit cells fully describe diffraction intensities of the main reflections and their satellites. A universal distribution, valid for different lengths of the modulation vector, has been found. Average Patterson functions have been constructed and used to distinguish between different types of modulation.     

Helical twisting power of antiferroelectric chiral terphenyls in different matrices

To determine the influence of chemical structure on the Helical Twisting Power (HTP), we tested four optically active dopants having a terphenyl rigid core and the same chiral centre but differing in the length of nonchiral terminal chain and the substitution of benzene rings with fluorine atoms. The compounds were added to different achiral liquid crystalline matrices: nematic and smectic C. It was found that HTP as well as its temperature variation depends on the kind of used matrices. It gives a conclusion that information about HTP obtained in one matrix cannot be uncritically transferred to another one.     

Quantum corrections to ϕ 4 model solutions and applications to Heisenberg chain dynamics

The Heisenberg spin chain is considered in ? ⁴ model approximation. Quantum corrections to classical solutions of the one-dimensional ? ⁴ model within the correspondent physics are evaluated with account of rest d-1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of spacetime functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional integral and quantum corrections to energy in a quasiclassical approximation. The results are applied to appropriate conditions of the spin chain model and its dynamics, for which elementary solutions, energy and the quantum corrections are calculated.