Z2Z4-additive cyclic codes, generator polynomials and dual codes

A ${\mathbb{Z}}_2{\mathbb{Z}}_4$-additive code ${\cal C}\subseteq{\mathbb{Z}}_2^\alpha\times{\mathbb{Z}}_4^\beta$ is called cyclic if the set of coordinates can be partitioned into two subsets, the set of ${\mathbb{Z}}_2$ and the set of ${\mathbb{Z}}_4$ coordinates, such that any cyclic shift of the coordinates of both subsets leaves the code invariant. These codes can be identified as submodules of the $\mathbb{Z}_4[x]$-module $\mathbb{Z}_2[x]/(x^\alpha-1)\times\mathbb{Z}_4[x]/(x^\beta-1)$. The parameters of a ${\mathbb{Z}}_2{\mathbb{Z}}_4$-additive cyclic code are stated in terms of the degrees of the generator polynomials of the code. The generator polynomials of the dual code of a ${\mathbb{Z}}_2{\mathbb{Z}}_4$-additive cyclic code are determined in terms of the generator polynomials of the code ${\cal C}$

A novel enzymatic approach to nanocrystalline cellulose preparation

In this work, conditions for an enzymatic pretreatment prior to NCC isolation from cotton linter were assessed. Different cellulase doses and reaction times were studied within an experimental design and NCC were obtained. At optimal enzymatic conditions (20U, 2 h), a total yield greater than 80% was achieved and the necessary enzymatic treatment time was reduced 90%. Different intensities of enzymatic treatments led to proportional decreases in fiber length and viscosity and also were inversely proportional to the amount of released oligosaccharides. These differences within fibers lead to quantitative differences in NCC: increase in acid hydrolysis yield, reduction of NCC surface charge and crystallinity increase. Benefits produced by enzymatic treatments did not have influence over other NCC characteristics such as their sulfur content (˜1%), size (˜200 nm), zeta potential (˜-50 mV) or degree of polymerization (˜200). Evidence presented in this work would reduce the use of harsh sulfuric acid generating a cleaner stream of profitable oligosaccharidesPostprint (author's final draft

Cellulose oxidation by Laccase-TEMPO treatments

In this work, laccase-TEMPO (Lac-T) treatments were applied to bleached commercial dissolving pulp in order to introduce carbonyl and carboxyl groups, which were found to improve dry and wet strength-related properties. Also the solubility behavior towards xanthate reactions was assessed. The effect of a refining step (R) before the oxidative treatment, the absence or presence of oxygen pressure, TEMPO dose (2 or 8% oven dried pulp) and reaction time (8 or 20 h) were thoroughly examined. Treatments conducted in the presence of oxygen pressure exhibited greater amount of functional groups. Introducing a pre-refining treatment resulted in similar functional groups but higher wet strength was achieved. Specifically, a high W/D strength ratio was observed, indicating that wet strength-related property was satisfactorily developed. Besides the fact that all Lac-T treatments caused severe cellulose degradation, no fiber strength loss was detected. In fact, all oxidized samples presented higher Wet Zero-Span Tensile Strength, mainly in R+ Lac-T (O2) sample, which suggested the formation of hemiacetal linkages between the new introduced aldehyde groups and available free hydroxyl groups resulting from fibrillationPostprint (author's final draft

Political Foundations of Universalistic Care Policy: Comparative Politics of Elderly Care Policy in Japan, the U.S., and Sweden

Two enzyme treatments involving xylanase (X) and laccase (L) were used jointly in an XLE sequence (where E denotes alkaline extraction) to bleach oxygen-delignified eucalyptus kraft pulp in the presence of 1-hydroxybenzotriazol (HBT) as mediator. The results of the XLE sequence were compared with those of an LE sequence. The application conditions for the laccase–mediator system were optimized by using a sequential statistical plan involving three variables (viz., the laccase and mediator doses, and the reaction time) with both sequences. The models used to predict the kappa number and brightness revealed that, once all accessible lignin was removed, the system altered other coloured compounds. The best conditions for the L stage involved a reduced mediator dose (0.5% odp). The xylanase pretreatment increased the accessibility of residual lignin and facilitated removal of hexenuronic acids. For a specific target brightness level of 70% ISO, the X pretreatment can save as much as 30% laccase and 80% mediator while shortening the reaction time by 45%.Peer ReviewedPostprint (published version

On ZprZps-additive cyclic codes

Publicació amb motiu de la 21st Conference on Applications of Computer Algebra (July 20-24, 2015, Kalamata, Greece

Mesura de la transmitància espectral de les diverses lents que es comercialitzen amb filtres de llum blava pels usuaris de dispositius digitals

En la societat actual, cada vegada és més freqüent l’ús de dispositius digitals, tals com les tauletes, els ordinadors o els mòbils. Les pantalles d'aquests aparells sovint presenten una il·luminació pròpia (retro-il·luminació) formada per una matriu de LEDs. Amb la millora de la tecnologia LED, s'han aconseguit sistemes d'il·luminació amb millor rendiment, que reprodueixen una àmplia gamma de colors, amb bon contrast, i permetent pantalles més primes. No obstant, els LEDs blancs tenen un pic d'emissió en la zona blava de l'espectre visible que, segons alguns estudis, podria ser perjudicial per la salut visual i ocular dels usuaris. Recentment, s’estan realitzant molts estudis sobre la possible influència negativa de la llum blava/violeta en el sistema visual humà i en el ritme circadiari (cicle de vetlla i son). Aquest fet ha donat peu a l'aparició en el mercat de vidres oftàlmics innovadors que incorporen uns filtres específics per absorbir part de la component blava de l'espectre. Aquestes lents van adreçades especialment a usuaris exposats moltes hores del dia a dispositius digitals. En el present treball, s’han mesurat, amb un espectroradiòmetre, les radiàncies espectrals de diverses mostres de lents amb filtre blau, interposant-les a una tauleta amb retroil·luminació LED. Per comparació amb la radiància espectral de la tauleta, s'ha mesurat el grau d'absorció de lents procedents de 4 fabricants diferents. S'ha determinat que el percentatge de filtratge de la llum blava varia molt segons el fabricant, i que és necessari establir el llindar d'absorció recomanat en funció dels efectes negatius que determinin les investigacions actuals

La construcción del discurso de Alguna Pregunta Mes? mediante el montaje audiovisual

Treball Final de Grau en Comunicació Audiovisual. Codi: CA0932. Curs acadèmic: 2016/201