Development and characterization of thin printed films for gas sensing applications

The monitoring and control of hydrogen sulfide (H2S) level is of great interest for a wide range of application areas including food quality control, defense and antiterrorist applications and air quality monitoring e.g. in mines. H2S is a very poisonous and flammable gas. Exposure to low concentrations of H2S can result in eye irritation, a sore throat and cough, shortness of breath, and fluid retention in the lungs. These symptoms usually disappear in a few weeks. Long-term, low-level exposure may result in fatigue, loss of appetite, headache, irritability, poor memory, and dizziness. Higher concentrations of 700 - 800 ppm tend to be fatal. H2S has a characteristic smell of rotten egg. However, because of temporary paralysis of olfactory nerves, the smelling capability at concentrations higher than 100 ppm is severely compromised. In addition, volatile H2S is one of the main products during the spoilage of poultry meat in anaerobic conditions. Currently, no commercial H2S sensor is available which can operate under anaerobic conditions and can be easily integrated in the food packaging. This thesis presents a step-wise progress in the development of printed H2S gas sensors. Efforts were made in the formulation, characterization and optimization of functional printable inks and coating pastes based on composites of a polymer and a metal salt as well as a composite of a metal salt and an organic acid. Different processing techniques including inkjet printing, flexographic printing, screen printing and spray coating were utilized in the fabrication of H2S sensors. The dispersions were characterized by measuring turbidity, surface tension, viscosity and particle size. The sensing films were characterized using X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy and an electrical multimeter. Thin and thick printed or coated films were developed for gas sensing applications with the aim of monitoring the H2S concentrations in real life applications. Initially, a H2S gas sensor based on a composite of polyaniline and metal salt was developed. Both aqueous and solvent-based dispersions were developed and characterized. These dispersions were then utilized in the fabrication of roll-to-roll printed H2S gas sensors. However, the humidity background, long term instability and comparatively lower detection limit made these sensors less favourable for real practical applications. To overcome these problems, copper acetate based sensors were developed for H2S gas sensing. Stable inks with excellent printability were developed by tuning the surface tension, viscosity and particle size. This enabled the formation of inkjet-printed high quality copper acetate films with excellent sensitivity towards H2S. Furthermore, these sensors showed negligible humidity effects and improved selectivity, response time, lower limit of detection and coefficient of variation. The lower limit of detection of copper acetate based sensors was further improved to sub-ppm level by incorporation of catalytic gold nano-particles and subsequent plasma treatment of the sensing film. These sensors were further integrated in an inexpensive wirelessly readable RLC-circuit (where R is resistor, L is inductor and C is capacitor). The performance of these sensors towards biogenic H2S produced during the spoilage of poultry meat in the modified atmosphere package was also demonstrated in this thesis. This serves as a proof of concept that these sensors can be utilized in real life applications.

Utilization of recycled mineral wool as filler in wood plastic composites

The impact of a recycled mineral wool filler on the various properties of wood plastic composites was studied and the critical factors affecting the formation of the properties were determined. An estimation of the volume of mineral wool fiber waste generated in the European Union between the years 2010-2020 was presented. Furthermore, the effect of fiber pre-treatment on the properties of the wood plastic composites were studied, and the environmental performance of a wood plastic composite containing recycled mineral fibers was assessed. The results showed that the volumes of construction and demolition waste and new mineral wool produced in the European Union are growing annually, and therefore also the volumes of recycled mineral wool waste generated are increasing. The study showed that the addition of recycled mineral wool into composites can enhance some of the mechanical properties and increase the moisture resistance properties of the composites notably. Recycled mineral wool as a filler in wood plastic composites can also improve the fire resistance properties of composites, but it does not protect the polymer matrix from pyrolysis. Fiber pre-treatment with silane solution improved some of the mechanical properties, but generally the use of maleated polypropylene as the coupling agent led to better mechanical and moisture resistance properties. The environmental performance of recycled mineral wool as the filler in wood plastic composites was superior compared to glass fibers. According to the findings, recycled mineral wool fibers can provide a technically and environmentally viable alternative to the traditional inorganic filler materials used in wood plastic composites.

Propiedades de textura de masa y pan dulce tipo "concha" fortificados con proteínas de suero de leche

La fortificación de alimentos es importante debido a una creciente población en estado de malnutrición, por las sequías provocadas a nivel mundial y por personas de bajos recursos económicos. La adición de proteínas puede causar problemas tecnológicos. Por ello, el objetivo de este trabajo fue determinar el efecto de la adición de proteínas de lactosuero a pan dulce tipo "concha" sobre las propiedades químicas y de texturas de las masas y panes. Se planteó un experimento con diferentes concentraciones de suero comercial y precipitado por calor, se evaluó la adhesividad y el análisis del perfil de textura en masa y panes. Los resultados indicaron que el testigo presentó menor contenido de proteína (17.2 ± 0.01%) con respecto a los panes con 10% (19.8 ± 0.01) y 15% (22.9 ± 0.03) de suero comercial y precipitados por calor, el contenido de grasa fue similar en el testigo (7.01 ± 0.02) y en los panes con suero comercial (7.29 ± 0.04%) y precipitado por calor (7.37 ± 0.01), el mayor trabajo de adhesión se presentó al 10% de suero comercial, mientras que los tratamientos a base de suero tuvieron valores intermedios. La firmeza fue mayor (p < 0.05) en las muestras con proteína de suero comercial, pero menos cohesiva que las fortificadas con suero precipitado por calor. La firmeza del pan mejoró por la presencia de suero lácteo comercial que con el suero precipitado por calor, sin detectar diferencia significativa (p > 0.05) entre los porcentajes de suero. Existe un efecto del tipo y concentración de suero en la adhesividad de las masas. Respecto a la textura de los panes, el suero precipitado por calor tuvo características aceptables en comparación con el suero comercial.

Physicochemical and sensory characteristics of pan bread samples available in the Brazilian market

Pan bread samples available in the Brazilian market were evaluated for their physicochemical and sensory characteristics. Twelve pan breads, seven white and five whole grain breads, were evaluated. Moisture, water activity (Aw), firmness, and color (L*, a*, b*) of the crumb were evaluated on the first, fourth, seventh, and tenth days after purchasing the breads. Specific volume was evaluated on the first day of analysis with averages of 4.72 and 4.70 mL/g for the white and whole grain breads, respectively. The average results on the first day of analysis were: 37.03% and 41.23% moisture, 0.954 and 0.966 Aw, 276.27 and 267.83 gf firmness, 74.73 and 64.45 L* values, 0.37 and 3.85 a* values, and 15.51 and 18.98 b* values for the white and whole grain breads, respectively. The samples showed an increase in firmness, reduction in moisture and Aw, and no color changes over time. A survey conducted prior to the acceptance test showed that the three most important factors influencing purchase were taste (19.6%), tenderness (16.8%), and expiration date of the product (14.3%). The results showed that 37.2% of the panelists preferred white bread, 62.8% preferred bread with fibers, and 82.6% would probably or definitely buy white bread with fibers.

Pohjola vai Baltia? Suomalaisten pan-identifioituminen 1920-1930 -luvuilla kansalaisyhteistyön valossa

Mäkinen, Riitta Pohjola vai Baltia? Suomalaisten pan-identifioituminen 1920-1930 -luvuilla kansalaisyhteistyön valossa. 249 s. + liite 9 s. Lisensiaatintutkimus, Turun yliopisto, Poliittisen historian laitos 5.2.2015 ____________________ Iskulause ”Suomi kuuluu Pohjolaan” ilmaisee kuulumisen tunnetta, jota voi kutsua pan- identifikaatioksi. Suomalaisten identifioituminen pohjoismaalaisiksi on ollut selvää toisesta maailmansodasta lähtien, mutta ei aikaisempina vuosikymmeninä. Nuoren itsenäisen Suomen ulkosuhteiden historia on tutkittu tarkoin valtiojohdon kannalta, mutta kansalaistaso on jäänyt toistaiseksi vähälle. Tässä tutkimuksessa fokuksessa ovat kansalaisten kokemukset läntisistä (Skandinavia) ja eteläisistä (Baltia) naapurisuhteista, sekä kontakteista Unkariin. Havaintoja tutkitaan kansalaistoiminnan ulkomaanvaihdon kuvauksista. Nationalismitutkimuksessa etsitään usein yhteenkuuluvuuden konstruointia, mutta tässä tutkimuksessa yhteenkuuluvuuden tai sen puutteen kokemuksia ja ilmaisua kontaktitilanteissa, joiden ensisijainen tarkoitus on järjestön tai muun kansalaistoiminnan omien tavoitteiden toteuttaminen. Pääaineistona on kolmen sanomalehden vuosikerrat 1922, 1930 ja 1930 sekä joukko erityyppisten järjestöjen lehtiä 1920–1939 (tai ilmestyneet vuosikerrat). Lisäaineistoina on mm. muutamia muita lehtivuosikertoja, matkakuvauksia sekä digitoiduista aineistoista tavoitettuja lehtikirjoituksia. Ilmeni, että suomalaisten pohjoismaisuus oli 1920-luvulla lähinnä ruotsin- ja kaksikielisen sivistyneistön varassa. Muiden kontakteja rasitti läntinen näkemys suomenkielisten ”eriverisyydestä”, jopa alempirotuisuudesta. Etelänaapureiden kanssa taas koettiin poliittisesta asemasta johtuvaa yhteenkuuluvuutta. Viron kanssa käynnistyi yhteistyötä, jota tuki auttava kielellinen yhteys. Epämääräisyydestään huolimatta skandinavismia kansanomaisempi heimoaate sai paljon kannatusta suomenkielisessä keskiluokan järjestökentässä. Aatteella oli siis ”matalampi” ilmentymänsä tunnetumman voimapoliittisen painotuksen rinnalla. 1930-luvun jälkipuoliskolla pohjoismainen yhteistyö lisääntyi nopeasti ja näyttäytyi luontevana sitä aiemmin vierastaneissakin järjestöissä. Syynä oli ennen kaikkea uhkaava kansainvälispoliittinen tilanne, mutta tulkitsen, että muutoksen mahdollistivat uudet rotujaottelut, joissa suomalaisten ”toiseus” kumottiin. Lisäksi valtiovallan Pohjoismainen julistus otettiin Suomessa suorastaan kansalaisvelvollisuutena. Tutkimus tuotti kaksi sivutulosta: Aineistot eivät lainkaan tue tavanomaista käsitystä suomalaisten sotien välisen ajan ”sisäänpäinkään käpertymisestä”. Toisekseen tutkimuskirjallisuudessa yleisesti paheksuttu aitosuomalaisten ”kiihkoilu” saa ymmärtävää selitystä. Asiasanat: Alueellinen yhteistyö, identiteettipolitiikka, Itämeren alue, Suomi

Research progress in wood-plastic composites: A review

The interest towards wood-plastic composites (WPCs) is growing due to growing interest in materials with novel properties, which can replace more traditional materials, such as wood and plastic. The use of recycled materials in manufacture is also a bonus. However, the application ofWPCs has been limited because of their often poor mechanical and barrier properties, which can be improved by incorporation of the reinforcing fillers. Nanosized fillers, having a large surface area, can significantly increase interfacial interactions in the composite on molecular level, leading to materials with new properties. The review summarizes the development trends in the use on nanofillers for WPC design, which were reported in accessible literature during the last decade. The effect of the nanofillers on the mechanical properties, thermal stability, flammability and wettability ofWPC is discussed.

Viologen based electroactive polymers and composites for durable electrochromic systems

Electrochromism, the phenomenon of reversible color change induced by a small electric charge, forms the basis for operation of several devices including mirrors, displays and smart windows. Although, the history of electrochromism dates back to the 19th century, only the last quarter of the 20th century has its considerable scientific and technological impact. The commercial applications of electrochromics (ECs) are rather limited, besides top selling EC anti-glare mirrors by Gentex Corporation and airplane windows by Boeing, which made a huge commercial success and exposed the potential of EC materials for future glass industry. It is evident from their patents that viologens (salts of 4,4ʹ-bipyridilium) were the major active EC component for most of these marketed devices, signifying the motivation of this thesis focusing on EC viologens. Among the family of electrochromes, viologens have been utilized in electrochromic devices (ECDs) for a while, due to its intensely colored radical cation formation induced by applying a small cathodic potential. Viologens can be synthesized as oligomer or in the polymeric form or as functionality to conjugated polymers. In this thesis, polyviologens (PVs) were synthesized starting from cyanopyridinium (CNP) based monomer precursors. Reductive coupling of cross-connected cyano groups yields viologen and polyviologen under successive electropolymerization using for example the cyclic voltammetry (CV) technique. For further development, a polyviologen-graphene composite system was fabricated, focusing at the stability of the PV electrochrome without sacrificing its excellent EC properties. High electrical conductivity, high surface area offered by graphene sheets together with its non-covalent interactions and synergism with PV significantly improved the electrochrome durability in the composite matrix. The work thereby continued in developing a CNP functionalized thiophene derivative and its copolymer for possible utilization of viologen in the copolymer blend. Furthermore, the viologen functionalized thiophene derivative was synthesized and electropolymerized in order to explore enhancement in the EC contrast and overall EC performance. The findings suggest that such electroactive viologen/polyviologen systems and their nanostructured composite films as well as viologen functionalized conjugated polymers, can be potentially applied as an active EC material in future ECDs aiming at durable device performances.

7-3-20, course de côte d'Argenteuil [motocyclisme], Péan sur Peugeot [500 cmc] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58371

Pan : revue libre...

1910/01 (A3,N1)-1910/02 (A3,N2).

Pan : revue libre...

1910/03 (A3,N3)-1911/01 (A3,N12).

Pan : revue libre...

1913/01 (A6,N1)-1913/05/25 (A6,N4).

Pan : revue libre...

1911/01 (A4,N1)-1911/12 (A4,N12).

Pan : revue libre...

1913/05/25 (A6,N5)-1913/07/25 (A6,N6).

Pan (Lyon. 1908)

Périodicité : Bimestriel (1908) ; mensuel (1909-1913)