The Influence of NIR Pigments on Coil Coatings’ Thermal Behaviors

The effect of over-heating in urban areas, called the urban heat island effect (UHI effect), is responsible for greater energy consumption for cooling buildings. Several reflective near-infrared (NIR) coatings, called cool coatings have proved to be effective for contrasting the UHI effect. The thermal and appearance properties of cool coatings depend on the color and they often have been studied only at the initial state, without undergoing atmospheric degradation and soiling. In this work, the thermal, visual and durability behaviors of red and brown polyester-based organic coatings for roof applications were studied. All samples were subjected to accelerated degradation cycles composed of UV-B and salt spray chamber exposure. The sample degradation was assessed by infrared spectroscopy, gloss and colorimetric analyses. Moreover, the thermal behavior was studied by means of a simplified experimental setup. Finally, a soiling and weathering test was conducted to simulate the soiling of three years’ external exposure. Despite the phenomena of chemical degradation and a decrease in aesthetic properties, the samples maintain their thermal performance, which is not even influenced by dirt products. In addition, NIR pigments significantly improve the thermal behavior of brown coatings

Determination of CO2 Content in the Headspace of Spoiled Yogurt Packages

The CO2 formation during food storage can often be correlated with the increase in yeast population. Yogurt and other dairy products are susceptible to yeast contamination. Accumulation of CO2 in the headspace of yogurt packages can lead to the eventual blowing off of the package. Therefore, determination of CO2 in the yogurt packages can indicate eventual unsafety of the product. The aim of this paper was to determine CO2 concentration in the headspace of different yogurt containers contaminated with yeast at the levels of 1 and 5 CFU/ml. Yeast Candida kefyr, previously isolated from spoiled yogurt, was used for contamination. Contaminated and control samples of yogurt were incubated at 30°C. A device based on tunable diode laser absorption spectroscopy was used for the measurement of CO2 concentration. The CO2 content in all analysed samples changed in a similar manner with slow increase to the value of 6% during the first 30 h and, after that, rapid accumulation to 17–20%. The initial level of yeast contamination did not have significant influence to the CO2 content trend. The increase in the number of yeast was observed after 10 h of incubation, and the final value of 6-7 log·CFU/cm3 was reached after 40 h of incubation. The significant increase in the yeast number can be correlated with the CO2 content in a way that CO2 concentration of 6% can be considered as critical for microbial spoilage. Since the TDLAS technique is simple and nondestructive, it can be a promising possibility for detection of the microbial spoilage in food

A system for 3D modeling frescoed historical buildings with multispectral texture information

This work proposes a system for the automatic construction of multi-spectral three-dimensional (3D) models of architecture. Besides the specific application, which concerns the interactive visualization and the restoration of historical buildings, the interest of the proposed system lies in the instrumental gap it fills in the multi-spectral nature of the textures, in general needed for rendering with faithful colors, and in the automatism of the 3D model construction. The paper presents a robust procedure for matching 3D points of architecture scenes and a new multiresolution method for texture generation. The proposed system is an effective tool for producing 3D content amenable to a great number of usages

Nanostructure Tuning of Gold Nanoparticles Films via Click Sintering

: Colloidal metal nanoparticles dispersions are commonly used to create functional printed electronic devices and they typically require time-, energy- and equipment-consuming post-treatments to improve their electrical and mechanical properties. Traditional methods, e.g. thermal, UV/IR, and microwave treatments, limit the substrate options and may require expensive equipment, not available in all the laboratories. Moreover, these processes also cause the collapse of the film (nano)pores and interstices, limiting or impeding its nanostructuration. Finding a simple approach to obtain complex nanostructured materials with minimal post-treatments remains a challenge. In this study, a new sintering method for gold nanoparticle inks that called as "click sintering" has been reported. The method uses a catalytic reaction to enhance and tune the nanostructuration of the film while sintering the metallic nanoparticles, without requiring any cumbersome post-treatment. This results in a conductive and electroactive nanoporous thin film, whose properties can be tuned by the conditions of the reaction, i.e., concentration of the reagent and time. Therefore, this study presents a novel and innovative one-step approach to simultaneously sinter gold nanoparticles films and create functional nanostructures, directly and easily, introducing a new concept of real-time treatment with possible applications in the fields of flexible electronics, biosensing, energy, and catalysis

FLY-SPEC prototype: UV-VIS-NIR reflectometry and laser induced breakdown spectroscopy

Development of efficient, non-destructive, time-saving and innovative instruments for material identification surveying is urgently requested in several fields, including solid-state physics, industrial processing, waste recycling and environmental contamination detection. In this respect, coupling laser-induced breakdown spectroscopy (LIBS) and (near-infrared unit) NIR reflectometry with hyperspectral imaging spectroscopy (HIS), owing to its power and versatility, is key to more efficient and time-saving diagnostic of chemical and physical properties of rocks and unconsolidated materials. Here we present the FLY-SPEC instrument conceived to combine these three relevant techniques for space exploration surveying. The recent assemblage of its LIBS unit has allowed us to conduct our first pilot experiments