Surfaces

Surface chemistry plays a major role in photocatalytic and photoelectrochemical processes taking place with the participation of TiO2. The synthesis methods, surface characterizations, theoretical research methods, and hardware over the last decade generated opportunities for progress in the surface science of this photocatalyst. Very recently, attention was paid to the design of photocatalysts at the nanoscale level by adjusting the types of exposed surfaces and their ratio, the composition and the surface structure of nanoparticles, and that of individual surfaces. The current theoretical methods provide highly detailed designs that can be embodied experimentally. The present review article describes the progress in the surface science of TiO2 and TiO2-based photocatalysts obtained over the last three years. Such aspects including the properties of macro- and nano-scale surfaces, noble-metal-loaded surfaces, doping with Mg and S, intrinsic defects (oxygen vacancies), adsorption, a...

The molecular structures of partially cured polyaminopropylsilsesquioxane and aminopropyltriethoxysilane in water have been studied using Fourier-transform infrared, laser Raman, and quasielastic laser light-scattering spectroscopy. A multiply hydrogen-bonded structure is proposed for the intramolecularly interacting amine and silanol groups on the basis of isotope exchange experiment and conformational energy calculations. Conformational restrictions are rather low for the proposed structure, which is thus suitable for the partially cured solid where there are slight perturbations by the surrounding amine and silanol groups. The O.…N distance was experimentally determined to be in the range 2.70–2.67 Å and estimated theoretically as 2.49–2.45 Å. The aminosilane in very dilute solution is found to be mostly monomeric. The isolated monomer-oligomer transition lies around 0.15% by weight and this transition influences the amount of silane uptake by glass fibers. It is also proposed that this phenomenon may be general for surface treatments by silane coupling agents. Hydrolyzed aminosilane oligomers exist in part as submicron aggregates which can be broken up by the addition of an alcohol. The neutralized aminosilane hydrolyzes very slowly although it dissolves in water instantaneously. Micelle formation is also proposed.

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases the metal ion ratio. Using OES and observing both Ti neutrals and ions, it was confirmed that the relative ionization could be qualitatively extended with grid-attached magnetron sputtering compared with a conventional magnetron system. On the other hand, the relative ionization of Ar decreased. Our results also show that the Ti films deposited by conventional magnetron exhibit (100) preferred orientation as the bias voltage increased. On the other hand, in the case of the grid-attached magnetron, the Ti films exhibit highly preferred (002) orientation with increasing bias voltage. The experiments clearly demonstrated that a dense Ti film with a smooth, specular reflecting surface can be produced using the grid-attached magnetron with increased Ti ion flux compared to the conventional magnetron.

La Geometría Descriptiva es exacta; quizá por esto la vemos como ciencia y en ocasiones ha sido incluida entre las matemáticas. Pero no vio la luz en el silencioso gabinete de un sabio; nació entre la polvareda de las lonjas de los canteros y el fragor de los duelos de artillería. Muchas de las nociones centrales de la disciplina, como la proyección ortogonal o el abatimiento, no fueron concebidas en abstracto; por el contrario, tomaron forma empíricamente en manos de los artífices del último gótico y el Renacimiento. Gaspard Monge, profesor de Teoría del Corte de las Piedras en la Escuela de Ingenieros de Mezières, no hizo otra cosa que sistematizar este saber y acuñar la expresión que todavía lo designa. Una de estas nociones que han cristalizado lentamente, por prueba y error, es la de superficie reglada; todavía aludimos a la regla de los canteros cuando la nombramos. También es antigua la distinción entre regladas desarrollables y alabeadas o engauchidas, pero el conocimiento de las propiedades de estas superficies no avanzó sin esfuerzo; durante largo tiempo se intentó desarrollar las superficies alabeadas y labrarlas con ayuda de plantillas. Visto con los ojos de nuestra época, el empeño es absurdo; pero en la edad de oro de la cantería clásica, en un arco temporal que va de 1560 a 1730, se pusieron en práctica algunas soluciones ingeniosas al problema, tanto en España como en Francia. Por tanto, consideramos que puede tener interés analizar el tratamiento de las superficies regladas en algunos manuscritos españoles de cantería, como los de Alonso de Vandelvira y Ginés Martínez de Aranda, para comprender mejor la formación empírica, por acumulación de una lenta experiencia, de estos conceptos.

This volume aims to uniform methodologies which can help to characterize biological agents such as allergens, bacteria, endotoxins, moulds, etc. indoor. Information are particularly addressed to those institutions appointed to microbiological controls and/or study of air and surface indoor with the aim of protecting human health. Key words: Air; Allergens; Bacteria; Indoor; Microbiological analysis; Moulds; Sampling techniques; Surfaces

Several ultrahard materials and coatings of definite interest for tribological applications were tested with respect to their response when irradiated with fs laser pulses. Results on cemented tungsten carbide and on titanium carbonitride are reported for the first time and compared with outcomes of investigations on diamond and titanium nitride. The experiments were carried out in air, in a regime of 5–8 J/cm2 fluences, using the beam of a commercial Ti:sapphire laser. The changes induced in the surface morphology were analysed with a Nomarski optical microscope, and with SEM and AFM techniques. From the experimental data and from the calculated incident energy density distributions, the damage and ablation threshold values were determined. As expected, the diamond showed the highest threshold, while the cemented tungsten carbide exhibited typical values for metallic surfaces. The ablation rates determined (under the above-mentioned experimental conditions) were in the range 0.1–0.2 μm per pulse for all the materials investigated.

This essay was written for the  catalogue of the Textures of Memory' exhibition, which I co-curated with Pamela Johnson. It explores the poetics of cloth, and in particular the fold,  drawing on ideas from  Gilles Deleuze and  Felix Guattari, Michel Serres, amongst others.

„Oberflächen untersichten!“ Dem auffordernden Charakter dieses Rufes sind die Autoren, die in der ersten Ausgabe versammelt sind, mit dankenswerter Gründlichkeit gefolgt. Die so entstandenen Beiträge haben wir in inhaltliche Gruppen gegliedert und das Thema dadurch nochmals strukturiert.
Nach einer notwendigen Herkunftsbestimmung der Oberflächen werden im Kapitel “Design untersichten” die, der Disziplin immanenten Oberflächenangelegenheiten verhandelt, eingeleitet durch ein Interview mit Gert Selle. Die Beiträge in “Oberflächliche Prägungen” setzen sich kritisch mit dem Konditionierungscharakter des Stylings auseinander und zeigen dies in verschiedenen gesellschaftlichen Szenarien auf. Inwieweit Material die Tiefenstruktur von Design determiniert und welche Ressourcenprobleme unter der Oberfläche warten, ist die leitende Frage in der Sektion “Material und Tiefenstruktur”. Dem veränderten Charakter der Dinge als Reduktion auf ihre Oberflächenperformanz wird in “Von der Textur zum Interface Rechnung getragen”. Wie heilsam ein hoher Gegenstandsbezug im Design sein kann, zeigen wir in “Vor und hinter der sozialen Oberfläche”; sind doch alle dort versammelten Beiträge Designforschungen, die sich am konkreten Design-Fall
abarbeiten.

Two-dimensional materials have secured a novel area of research in material science after the emergence of graphene. Now, a new family of 2D material-MXene is gradually growing and making itsmark in this field of study. MXenes since 2011 have been synthesized and experimented on in several ways.The HF treatment although successful poses some serious problems that gradually propelled the ideas of new synthesis methods. This review of the literature covers the major breakthroughs of MXene from the year of its discovery to recent endeavors, highlighting how the synthesis mechanisms have been developed over the years and also the importance of good characterization of data. Results and properties of this class of materials arealso briefly discussed alongwith recent advance in applications.