Bioactive efficacy of low‐density polyethylene films with natural additives

Active packaging can be defined as packaging that includes additives that help to extend the shelf life of food; among the advantages of its use is the possibility to reduce the amount of additives added to the food during processing. The aim of this study was to develop, characterize, and apply active films of low‐density polyethylene, incorporating carotenoid and yerba mate extracts as active additives. Active films were obtained by extrusion and were characterized for water vapor permeability, thickness, color, and mechanical and thermal properties. The effectiveness of the films was evaluated using butter packed in the formulated films. There was a significant reduction in thickness, and mechanical, thermal, and water vapor barrier parameters of the films compared to the control. The concentration of additives directly influenced coloration and antioxidant and antimicrobial action of the films. The formulated films provided protection against oxidative action and inhibition of microbial growth. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46461.     

Structural Stability and Optical Studies of Poly(3-hexylthiophene) in an ITO/PEDOT:PSS/P3HT Interface

An interface between poly(3-hexylthiophene) (P3HT) and poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) was prepared in LiClO_4-–acetonitrile (ACN) over indium-doped tin oxide (ITO), known as the ITO/PEDOT:PSS/P3HT system. This system was compared with ITO/P3HT with the aim of studying the stability of aromatic, quinone, and semiquinone segments in the polymer matrix and also elucidating the influence of the structure on the efficiency of organic photovoltaic cells (OPVs). Initially, Raman spectroscopy was used, varying the laser power to verify the destabilization of radical cation segments to dication segments in the ITO/P3HT system. Electrochemical impedance spectroscopy (EIS) was used to show the behavior of the charged species and the charge-transfer processes of the different P3HT segments as a function of time since preparation of the studied systems. In addition, photoluminescence (PL) and time-resolved PL spectroscopy showed the optical properties of the interfaces formed, based on the different quantities of segments present. It was possible to conclude that the modification introduced into the interface by PEDOT:PSS favors stabilization of the P3HT radical cation segment, which remains stable in this interface for lengthy periods (240 h). This should in turn boost hole extraction, increasing OPV efficiency.     

Hardware/firmware implementation of a soft sensor using an improved version of a fuzzy identification algorithm

This paper presents the design and implementation of an embedded soft sensor, i.e., a generic and autonomous hardware module, which can be applied to many complex plants, wherein a certain variable cannot be directly measured. It is implemented based on a fuzzy identification algorithm called "Limited Rules", employed to model continuous nonlinear processes. The fuzzy model has a Takagi-Sugeno-Kang structure and the premise parameters are defined based on the Fuzzy C-Means (FCM) clustering algorithm. The firmware contains the soft sensor and it runs online, estimating the target variable from other available variables. Tests have been performed using a simulated pH neutralization plant. The results of the embedded soft sensor have been considered satisfactory. A complete embedded inferential control system is also presented, including a soft sensor and a PID controller.     

Structure, hardness and thermal stability of Ti(Al,N) coatings

In the past two decades, coatings of the Ti-Al-N ternary system have attracted considerable research and industrial interest. Nevertheless, the Ti-Al-N system still offers new interesting possibilities for coating developments such as the addition of low N contents to Ti-Al films in order to reach a good compromise between high hardness and a low friction coefficient.Ti-Al-N coatings with low nitrogen content were deposited by closed field unbalanced magnetron sputtering using two facing Ti targets inserted with Al rods. The Al/(Al + Ti) and N/(Al + Ti + N) atomic ratios were varied from 21 to 28 at.% and 0 to 33 at.%, respectively.Hexagonal close-packed (hcp) α-Ti with a preferential <001> orientation was the only phase detected by X-ray diffraction in the as-deposited films. A decrease in the α-Ti c lattice parameter was observed as aluminium was added to the films. Nitrogen addition increased the c lattice parameter and led to a progressive loss of crystallinity until quasi-amorphous films were obtained. A hardness of ≈ 13 GPa was obtained for the as-deposited films without nitrogen. A continuous increase in hardness was observed with increasing nitrogen content. The highest hardness values (up to 27 GPa) were obtained for the quasi-amorphous films. Annealing of the films with low aluminium content (Al/Al + Ti ≈ 21 at.%) did not significantly affect their structure as hcp Ti remains the only phase detected. On the contrary, annealing of the films deposited with higher aluminium contents (Al/(Al + Ti) ≈ 24 and ≈ 28 at.%) resulted in the formation of face centered cubic (fcc) Al or Ti₃Al, showing that the thermal stability of the films decreased with aluminium incorporation.     

Thermal Treatment Effects on Microstructure and Mechanical Properties of TiAlN Thin Films

Effects of thermal treatment on the modification of microstructure and mechanical properties of Ti_1–x Al _x N thin films (x=0.4–0.7) were investigated. It was found that the Al content plays a major role on the thermal stability and change of hardness following to heating under vacuum. The samples with the Al content x < 0.6 showed a reduction of hardness after annealing for 30 min at 1000 °C. The hardness difference between the as deposited and thermally treated samples decreased when the Al content of the films was increased. In contrast, the Al-rich samples (x > 0.6) showed a nanocomposite structure and their hardness increased after thermal treatment. Microstructural analysis by X-ray diffraction and transmission electron microscopy (TEM) revealed that the reduction of hardness in single-phase coatings is due to partial relaxation of compressive stress while the increase of hardness in the nanocomposite coatings arises from coherency stresses developed during thermal treatment.     

Automatic recognition of handwritten numerical strings: a recognition and verification strategy

A modular system to recognize handwritten numerical strings is proposed. It uses a segmentation-based recognition approach and a recognition and verification strategy. The approach combines the outputs from different levels such as segmentation, recognition, and postprocessing in a probabilistic model. A new verification scheme which contains two verifiers to deal with the problems of oversegmentation and undersegmentation is presented. A new feature set is also introduced to feed the oversegmentation verifier. A postprocessor based on a deterministic automaton is used and the global decision module makes an accept/reject decision. Finally, experimental results on two databases are presented: numerical amounts on Brazilian bank checks and NIST SD19. The latter aims at validating the concept of modular system and showing the robustness of the system using a well-known database.     

The effects of processing conditions on the density and microstructure of hot-pressed silicon powder

Silicon powder was hot pressed into polycrystalline wafers 1.5 in ( 3.8 cm) diameter using various processing conditions. The submicrometre powder used was a by-product of the fluidized bed decomposition process of silane (SiH₄) in the production of silicon pellets. The effect of temperature (1250–1300°C), pressure (2000–3000 p.s.i.; 13.18–20.67 N mm^–2) and ambient (argon, hydrogen, vacuum) on the density of the hot-pressed powder was studied. All wafers processed had densities >92% of the theoretical density of silicon as determined by Archimedes' density measurements. Hydrogen was found to increase the densification rate of powdered silicon. The mechanism by which this occurs is believed to be the reduction of the native oxide layer of the powders resulting in increased surface transport. The microstructure of the polycrystalline wafers was examined by scanning electron microscopy, and transmission electron microscopy. The general microstructure of the polycrystalline wafers consisted of micrometre-sized grains with twins, stacking faults, and dislocations within the grains. However, under hot-pressing conditions of 1300 °C, 2000 p.s.i., and a hydrogen ambient, the grains of the wafer were on the order of 1 mm. The silicon wafers contained iron, aluminium, carbon and oxygen impurities as determined by secondary ion mass spectroscopy.     

Theoretical and Experimental Analysis of LED Lamp for Visible Light Communications

Wireless Personal Communications - Visible light communications (VLC) are an emerging technology that uses light-emitting diodes (LEDs) and photodiodes to provide high-speed communication between...     

Software-Defined Radio Enabled Cloud Radio Access Network Implementation Using OpenAirInterface

Wireless Personal Communications - Towards enabling 5G and beyond radio access technologies to meet the requirements for continuous dynamic and diverse services, flexibility and scalability of the...     

Intelligent forecasting of time series based on evolving distributed Neuro-Fuzzy network

An evolving methodology based on Neuro-Fuzzy Takagi-Sugeno network (NF-TS) for distributed forecasting of univariate time series, is proposed. First, the unobservable components, or hidden patterns, are extracted from experimental data of the time series. Then, a distributed forecasting is performed separately for each component, considering an evolving NF-TS associated with each extracted pattern. The evolving NF-TS uses components data to adapt and adjust its structure, as the number of fuzzy rules increases or decreases according the behavior of the unobservable components. A recursive version of singular spectral analysis (SSA) technique is formulated, as one of the main contributions of this article, and it is applied to extract the components. The efficiency of proposed methodology is illustrated from results of comparison to others state-of-the-art techniques for forecasting of various univariate time series.