Impact of heating method on the flocculation process using thermosensitive polymer

The impact of suspension heating method on the flocculation process using thermosensitive polymer is reported in this paper. In experiments a model suspension of chalk in RO water (purified by Reverse Osmosis) was destabilized using a copolymer of N-isopropylacrylamide (NIPAM) andcationic diallyldimethyl ammonium chloride (DADMAC). The measurements were made using a laboratory setup consisting of a mixing tank with four baffles, Rushton turbine, laser particle sizer Analysette 22 by Fritsch and a system of pump and thermostating devices. Two different modes of heating were used. In the first case the temperature of the system was gently raised above the Lower Critical Solution Temperature (LCST) using an electrical heater placed inside the tank, while in the second case the system temperature was rapidly raised by an injection of hot water directly into the tank. It was proven that heating method as well as the polymer concentration was crucial to the shape and size of created flocs.     

Twelve-year cohort study on the influence of caprine arthritis-encephalitis virus infection on milk yield and composition

This long-term observational cohort study was carried out to evaluate the effect of caprine arthritis-encephalitis virus (CAEV) infection on the quantitative and qualitative characteristics of milk production in dairy goats. For this purpose, a dairy herd comprising both CAEV-infected and uninfected female goats was observed for 12 consecutive years. Records on daily milk yield, somatic cell count (SCC), and contents of the major milk components (fat, protein and lactose) were collected every month. In total, 3,042 records (1,114 from CAEV-positive and 1,928 from CAEV-negative animals) from 177 female goats were used for statistical analysis. The multi-trait repeatability test-day animal model using the derivative-free multivariate analysis package with the average information-REML method was applied to eliminate the influence of factors other than CAEV infection on milk production in goats. The statistical significance of the differences between estimates for seropositive and seronegative goats was evaluated using Student's t-test. The effect of age of goats (parity) on their serological status was also estimated with the one-trait repeatability test-day model. The serological status of goats was linked to parity: the higher the parity, the greater the probability of CAEV infection. No significant differences between infected and uninfected goats with respect to daily milk yield and SCC were found. On the other hand, the milk of uninfected goats contained more total protein (3.40% vs. 3.35%), fat (3.69% vs. 3.54%), and lactose (4.30% vs. 4.25%) than the milk of infected goats. Even though these differences were highly significant, they were small when expressed numerically.     

Advanced AI Search Techniques in Modern Digital Circuit Synthesis

Progress in microelectronic technology is extremely fast and it is outstripping the designers' abilities to make use of the created opportunities. Development and application of new more suitable design methods and tools is therefore very important for the modern system industry. This paper shows the importance of the AI search techniques for the circuits and systems design space exploration, explains what sorts of search techniques are useful for this aim, and discusses the place, role and way of use of these techniques in circuit and system design. In particular, the paper explains the importance and usage of the heuristic search techniques for the automatic construction and selection of the most promising solutions to the circuit synthesis problems. The discussion and conclusions of the paper are illustrated with examples of three effective and efficient search algorithms, and experimental results from their application to two important circuit synthesis problems. The knowledge presented in the paper combines numerous valuable concepts of modern system engineering and artificial intelligence, and forms a base for further research and application of the AI search techniques to design of complex circuits and systems.     

Influence of side‐chain structures on the viscoelasticity and elongation viscosity of polyethylene melts

Metallocene‐catalyzed, low‐density and linear low‐density polyethylenes with similar melt indexes were used to investigate how side‐chain structures influence the elongation viscosity and viscoelastic properties. The viscoelastic properties were determined with a rotation rheometer, while the elongation viscosities were acquired by using isothermal fiber spinning. The Phan‐Thien‐Tanner (PTT) model was also used to understand how the side‐chain structure affects the elongation behavior. Experimental results demonstrate that the log G′ vs. log G″ plot can qualitatively describe the effects of the side chain branch on the rheological properties of polyethylene melts. According to the results determined by the PTT model, low‐density polyethylene (LDPE) has low elongation viscosities at high strain rates. This low elongation viscosity can be attributed to the fact that LDPE has high shear thinning behavior. The long‐chain branching tends to increase entanglements, thereby enhancing the storage modulus, elongation viscosity and shear‐thinning behaviors. Uniform side‐chain distribution lowers the entanglements, which results in a low storage modulus, elongation viscosity and shear‐thinning behavior.     

Antistatic and wetting properties of chemodegradable cationic surfactants containing 1,3-dioxolane moiety

In this paper we report some performance properties of [(2-alkyl-1,3-dioxolane-4-yl)methyl]trimethylammonium bromides (C _n -D-TAB, where C _n =n-C₉H₁₉, n-C₁₁H₂₃, n-C₁₃H₂₇), [(2,2-dialkyl-1,3-dioxolane-4-yl)methyl] dimethylammonium bromides (C _n C _m -D-TAB, where C _n =n-C₈H₁₇, n-C₁₀H₂₁ and C _m =CH₃ or C _n =C _m =n-C₆H₁₃), in relation to classical alkyltrimethylammonium bromides (C _n -TAB, where C _n =n-C₁₂H₂₅, n-C₁₄H₂₉ or C₁₆H₃₃) and dialkyldimethylammonium bromides (C _n C _m -DAB, where C _n =C _m =n-C₁₀H₂₁ and C₁₂H₂₅). Antistatic properties were measured by means of surface resistance (R _s), half charge decay time τ_1/2, and maximal voltage induced (U _ind) on polyethylene (PE) film and polypropylene (PP) nonwoven fabric. Wetting ability is reported as the concentration of surfactant necessary for immersion of a cottonfabric ring in 100 s, according to the Polish Standard PN-74/C-04800. All acetal-type surfactants showed the antistatic effect. The best results were given by C₉-D-TAB [R _s=8.5·10⁷ (PE), 1.1·10⁸ Ω (PP); τ_1/2=0.25 (PE), 0.30 s (PP); U _ind=205 (PE), 220 V (PP)] and C₁₁-D-TAB [R _s=8.7·10⁷ (PE), 1.3·10⁸ Ω (PP); τ_1/2=0.25 (PE), 0.30 s (PP); U _ind=190 (PE), 340 V (PP)] in relation to pure PE foils and PP fabric: R _s=3.0·10¹⁴ (PE), 9.8·10¹⁴ Ω (PP); τ_1/2=>600 (PE), >600 s (PP); U _ind=985 (PE), 940 V (PP). Both C₉-D-TAB and C₁₁-D-TAB indicate similar degrees of antistatic ability compared to C₁₀C₁₀-DAB. All C _n -TAB compounds do not show any antistatic effects. It was concluded that addition of the 1,3-dioxolane moiety to the hydrophobic tail of quaternary ammonium salts promotes both antistatic and wetting properties. Additionally, methyl or n-hexyl group incorporation at the C-2 carbon atom in the 1,3-dioxolane ring significantly decreases the surface conductivity.     

Speech nonfluency detection using Kohonen networks

This work covers the problem of application of neural networks to recognition and categorization of non-fluent and fluent utterance records. Fifty-five 4-s speech samples where the blockade on plosives (p, b, t, d, k and g) occurred and 55 recordings of speech of fluent speakers containing the same fragments were applied. Two Kohonen networks were used. The purpose of the first network was to reduce the dimension of the vector describing the input signals. A result of the analysis was the output matrix consisting of the neurons winning in a particular time frame. This matrix was taken as an input for the next self-organizing map network. Various types of Kohonen networks were examined with respect to their ability to classify utterances correctly into two, non-fluent and fluent, groups. Good examination results were accomplished and classification correctness exceeded 76%.     

Hierarchical ANN system for stuttering identification

The presented work covers the issue of applying neural networks to the recognition and categorization of non-fluent and fluent utterance records. Speech samples containing three types of stuttering episodes (blocks before words starting with plosives, syllable repetitions, and sound-initial prolongations) were applied. The proposed system, built with hierarchical neural network framework, was used and then evaluated with respect to its ability to recognize and classify disfluency types in stuttered speech. The purpose of the first network was to reduce the dimension of vector describing the input signals. The result of the analysis was the output matrix consisting of neurons winning in a particular time frame. This matrix was taken as an input for the next network. Various types of MLP networks were examined with respect to their ability to classify utterances correctly into two, non-fluent and fluent, groups. Good examination results were accomplished and classification correctness exceeded 84–100% depending on the disfluency type.     

Numerical Modeling of Photothermal Experiments on Layered Samples with Mirage-Effect Signal Detection

Modeling of the probe beam deflection caused by temperature gradients for layered sample was realized in COMSOL Multiphysics, which utilizes finite element method to analyze heat transport. The sample consisted of a 100-nm-thick layer on a 500-\(\upmu \)m-thick substrate. It was also assumed that the sample was illuminated with either a Gaussian or a flat top beam of harmonically modulated intensity. To obtain the probe beam deflection signal, the normal and tangential components of the temperature gradient in the air above the sample were integrated over the probe beam path. The numerical model of the experiment gave insight into the various parameter dependencies, e.g., the thermal and optical properties of the substrate and the layer, and the geometry of the experiment. These insights are used in the analysis of experimental data and in the planning of future measurements.     

Quantitative Thermal Microscopy Measurement with Thermal Probe Driven by dc+ac Current

Quantitative thermal measurements with spatial resolution allowing the examination of objects of submicron dimensions are still a challenging task. The quantity of methods providing spatial resolution better than 100 nm is very limited. One of them is scanning thermal microscopy (SThM). This method is a variant of atomic force microscopy which uses a probe equipped with a temperature sensor near the apex. Depending on the sensor current, either the temperature or the thermal conductivity distribution at the sample surface can be measured. However, like all microscopy methods, the SThM gives only qualitative information. Quantitative measuring methods using SThM equipment are still under development. In this paper, a method based on simultaneous registration of the static and the dynamic electrical resistances of the probe driven by the sum of dc and ac currents, and examples of its applications are described. Special attention is paid to the investigation of thin films deposited on thick substrates. The influence of substrate thermal properties on the measured signal and its dependence on thin film thermal conductivity and film thickness are analyzed. It is shown that in the case where layer thicknesses are comparable or smaller than the probe–sample contact diameter, a correction procedure is required to obtain actual thermal conductivity of the layer. Experimental results obtained for thin SiO\(_{\mathrm {2}}\) and BaTiO\(_{\mathrm {3 }}\)layers with thicknesses in the range from 11 nm to 100 nm are correctly confirmed with this approach.     

Magnetoresistance and Irreversibility Fields of Bismuth-Based 1G Tape

The magnetoresistance and irreversibility fields of commercial bismuth-based 1G tape were studied on the basis of the temperature dependencies of the magnetoresistance at the two relative orientations of magnetic field and superconductor plane. The critical temperatures of this tape are the following: T _{c50 %} = 110.3 K and T _c0 = 109.9 K, and the width of superconducting transition is ΔT = 0.5 K. The widths of the transition to the superconducting state versus applied magnetic fields were derived for both orientations. The experimental data were fitted using the formula ΔT = C H ^m + ΔT ₀. The irreversibility field values were obtained and successfully fitted as a function of temperature. At 77 K, they were found to amount to H _{i r r} = 72.8 kOe and H _{i r r} = 5.5 kOe for the parallel and perpendicular directions, respectively.