Induction of grape botrytization during withering affects volatile composition of Recioto di Soave, a “passito”-style wine

The influence of noble rot on the quality of Recioto di Soave, a “passito” sweet white wine, is greatly variable depending on the occurrence of favourable seasonal conditions for the mould infection. Botrytized wines were produced from grapes inoculated with conidia suspensions to evaluate the effects of noble rot on volatile compounds profile of Recioto di Soave wine. Different development stages of Botrytis cinerea and degree of grape withering were ascertained by must analysis. Several volatile components were involved in marked changes depending on the infection and grape withering level. Fruity esters, carbonyl compounds, phenols, lactones and acetamides greatly changed among botrytized wines. The results demonstrated that the level of B. cinerea infection and the degree of grape withering exert considerable influence on the volatile composition of this sweet wine. Strain-dependent effects were also preliminary ascertained. The process of induction of grape botrytization presented in this study could be recommendable for the industrial production of botrytized Recioto di Soave wine.     

Temperature‐Enhanced Solvent Vapor Annealing of a C3 Symmetric Hexa‐peri‐Hexabenzocoronene: Controlling the Self‐Assembly from Nano‐ to Macroscale

Temperature‐enhanced solvent vapor annealing (TESVA) is used to self‐assemble functionalized polycyclic aromatic hydrocarbon molecules into ordered macroscopic layers and crystals on solid surfaces. A novel C₃ symmetric hexa‐peri‐hexabenzocoronene functionalized with alternating hydrophilic and hydrophobic side chains is used as a model system since its multivalent character can be expected to offer unique self‐assembly properties and behavior in different solvents. TESVA promotes the molecule's long‐range mobility, as proven by their diffusion on a Si/SiO_x surface on a scale of hundreds of micrometers. This leads to self‐assembly into large, ordered crystals featuring an edge‐on columnar type of arrangement, which differs from the morphologies obtained using conventional solution‐processing methods such as spin‐coating or drop‐casting. The temperature modulation in the TESVA makes it possible to achieve an additional control over the role of hydrodynamic forces in the self‐assembly at surfaces, leading to a macroscopic self‐healing within the adsorbed film notably improved as compared to conventional solvent vapor annealing. This surface re‐organization can be monitored in real time by optical and atomic force microscopy.     

Multi-Prandtl correlating equations for free convection heat transfer from a horizontal tube of elliptic cross-section

Steady laminar free convection from a horizontal elliptic cylinder set in unbounded space is studied numerically under the assumption of uniform surface temperature. A specifically developed computer-code based on the SIMPLE-C algorithm is used for the solution of the mass, momentum and energy transfer governing equations. Simulations are performed for ratios between the minor and major axes of the elliptic cross-section of the cylinder in the range between 0.05 and 0.98, inclination angles of the major axis of the elliptic cross-section with respect to gravity in the range between 0° and 90°, Rayleigh numbers based on the major axis of the elliptic cross-section in the range between 10 and 10⁷, and Prandtl numbers in the range between 0.7 and 700. It is found that the heat transfer rate increases with increasing the Rayleigh and Prandtl numbers, while decreases with increasing the orientation angle of the cross-section of the cylinder, i.e., passing from the slender to the blunt configuration. In addition, a noteworthy fact is that in most cases the amount of heat exchanged at the cylinder surface has a peak at an optimum axis ratio which is practically independent of the Prandtl number, while may either increase or decrease with increasing the Rayleigh number depending on whether the orientation angle of the tube is above or below a critical value of approximately 67.5°. Dimensionless correlating equations are proposed both for the optimum axis ratio for maximum heat transfer and for the heat transfer rate from the cylinder surface to the undisturbed surrounding fluid reservoir.     

Thin-film solar cells on commercial ceramic tiles

Amorphous silicon solar cells were deposited on porcelain stoneware tiles in order to develop a fully integrated PV building element. In a previous work we demonstrated the feasibility of adopting porcelain stoneware tiles as thin-film solar cell substrates and we fabricated solar cells on “industrial-level” ceramic substrates showing more than 4% efficiency. In this study we focus our attention on larger area devices deposited on tiles. As the active area increases additional problems arise from the surface of the substrate. In particular we find that short-circuit paths originate from the unfavorable properties of the substrate tiles (roughness, porosity, etc.) having dramatic consequences on the performance of larger area devices. With the assumption that spot-like regions, in which the back layer and the front layer are in electrical contact (local short-circuits), are present all over the device, we propose a new device structure to overcome the substrate drawbacks. A new contacts arrangement was designed in order to minimize the shunting effect of short-circuit paths. As a result an initial efficiency of 2.5% has been obtained using the new device structure for devices deposited on a PV mini-module tile.     

Low Risk Synthesis of Energetic Poly(3‐Azidomethyl‐3‐Methyl Oxetane) from Tosylated Precursors

Azidated oxetanic polymers such as poly(3‐azidomethyl‐3‐methyl oxetane), are under investigation as “energetic” binder to be used as an alternative to polybutadiene in solid rocket propellants. The classic synthetic route for the production of the polymer is through an azidated monomer where the N₃⁻ functionality has been previously introduced by nucleophilic displacement of a suitable, usually a halogen, leaving group. However, this could involve critical steps with manipulation of a highly unstable liquid monomer. Here it is shown that the azidation can be performed as the final step of the preparation by substitution of the tosyl group in a preformed polymer. The procedure assures good yield and purity of the product and satisfactory rate of reaction, being the energetic functionality always kept in a safe form, which shows low shock and friction sensitivity. Poly(3‐azidomethyl‐3‐methyl oxetane) was prepared by azidation of poly(3‐tosyloxymethyl‐3‐methyl oxetane) in dimethylsulfoxide, testing several operating conditions. Moreover, hypothesizing a second order kinetics, the rate constant and the activation energy for the azidation step have been estimated.     

The application of dextran compared to other hydrocolloids as a novel food ingredient to compensate for low protein in biscuit and wholemeal wheat flour

Wheat is primarily used for bread-making. However, fungal diseases, grain moisture at harvest and low-protein contents strongly influence the quality of the wheat flour, thus creating challenges for traders, millers and commercial bakers who struggle to produce consistently high-quality products. This paper address the replacement of low-protein/wholemeal flour functionality for bread-making purposes. Three hydrocolloids, xanthan gum, dextran and hydroxypropyl methylcellulose, were incorporated into bread recipes based on high-protein flours, low-protein flours and coarse wholemeal flour. Hydrocolloid levels of 0–5 % (flour basis) were used in bread recipes to test the water absorption. The quality parameters of dough (farinograph, extensograph, rheofermentometre) and bread (specific volume, crumb structure and staling profile) were determined. Results showed that xanthan had negative impact on the dough and bread quality characteristics. HPMC and dextran generally improved dough and bread quality and showed dosage dependence. Volume of low-protein flour breads were significantly improved by incorporation of 0.5 % of the latter two hydrocolloids. However, dextran outperformed HPMC regarding initial bread hardness and staling shelf life regardless the flour applied in the formulation.     

隔板式内循环气化炉的设计和运行

介绍了一种新型的隔板式内循环气化炉的设计和运行。通过在气化炉的中间设置隔板,可使流化床气化炉的床层形成2个流化速度不等的流化区域,在高速区没有反应的原料或炭粒,在床层上部随流化介质流入低速区,在低速区内进行气化反应;未反应完的炭粒再经底部流回高速区,进一步进行气化反应,形成一个内部循环,从而达到延长原料在炉内的反应时间、增强气化效率的效果。实验结果表明:这种气化炉反应温度在790—850℃时,气化效果最好,产气率为1.6—1.9m3/kg,气体热值为5340kJ/m3(木质类原料)或4880kJ/m3(稻壳),气化效率可达70%。     

A theoretical analysis of a buffer frame size conversion algorithm for audio applications ensuring minimum latency

In implementing digital signal processing (DSP) algorithms for audio real-time applications, one is frequently faced with problems regarding incompatibilities between the hardware buffer length (the internal buffer of a professional sound card) and the software buffer size imposed by the underlying algorithm (due to i.e. multirate or FFT constraints). This mismatch is solved by proper frame size conversion algorithms which inevitably introduce delay. In this context, this paper presents a buffering scheme together with a theoretical proof of the minimum delay property shown by it. Some examples derived from frequently encountered issues in DSP applications are reported.     

Buoyant heat transport in fluids across tilted square cavities discretely heated at one side

Laminar natural convection heat transfer inside fluid-filled, tilted square cavities cooled at one side and partially heated at the opposite side, is studied numerically. A computational code based on the SIMPLE-C algorithm is used for the solution of the system of mass, momentum, and energy transfer equations. Simulations are performed for a complete range of heater sizes and locations, Rayleigh numbers based on the side of the cavity from 10³ to 10⁷, Prandtl numbers from 0.7 to 700, and tilting angles of the enclosure from ?75° to +75°, where negative angles correspond to configurations with the heater facing downwards. It is found that the heat transfer rate increases with increasing the Rayleigh and Prandtl numbers, and the size of the heater. In addition, for negative inclinations of the enclosure the amount of heat exchanged decreases with increasing the tilting angle, while for positive inclinations the heat transfer rate either increases or decreases according as the heater is located toward the top or the bottom of the cavity. Finally, as far as the heater location is specifically concerned, the heat transfer performance has a peak for intermediate positions, the higher are the Rayleigh and Prandtl numbers, as well as the tilting angle for positive inclinations, the closer to the bottom of the cavity is the optimum heater location for maximum heat removal.     

Interlaboratory study on lipid oxidation during accelerated storage trials with rapeseed and sunflower oil analyzed by conjugated dienes as primary oxidation products

Accelerated storage tests are frequently used to assess the oxidative stability of foods and related systems due to its reproducibility. Various methods and experimental conditions are used to measure lipid oxidation. Differences between laboratories make it necessary to determine the repeatability and reproducibility of oxidation tests performed under the same conditions. The objective of the present interlaboratory study was to evaluate the outcome of a storage test for two different bulk oils, sunflower oil (SFO) and rapeseed oil (RSO), during a period of 9 weeks at 20°C, 30°C, 40°C, and 60°C. Sixteen laboratories were provided with bottled oils and conducted the storage tests according to a detailed protocol. Lipid oxidation was monitored by the formation of conjugated dienes (CD) and the activation energy (E_a) was determined for comparative purposes and statistically evaluated. An increase in CD formation was observed for both oils when the storage temperature was increased in all laboratories. The E_a,1 ranged from 47.9 to 73.3 kJ mol⁻¹ in RSO and from 27.8 to 62.6 kJ mol⁻¹ in SFO, with average values of 58.2 and 46.8 kJ mol⁻¹, respectively. The reproducibility coefficients were 10.9% and 18.2% for RSO and SFO, respectively. Practical applications: In order to compare results on oxidative stability of foods derived from different studies, the reproducibility of storage tests and methods employed to evaluate the oxidation level should be considered. This study provides fundamental data on the reproducibility of lipid oxidation under accelerated storage conditions and defines important parameters to be considered for the conduction of experiments.