1,721,102 research outputs found
The sunk-panel book-binding of a Renaissance Venetian Commissione Dogale: the scientific examination of the decoration materials
Full text linkAbstract The research aims to investigate the nature of the materials used in the decoration of the cover of a sunk-panel Commissione Dogale, a Venetian manuscript of 1582. The analysed volume Ms. It. VII, 1869 (= 8134) belongs to the collections of the Biblioteca Nazionale Marciana, Venice. The Commissioni were intended as official documents written on parchment and issued by the Doge of Venice. Their bindings were very rich in decoration, especially those produced in the late 16th century. This manuscript is a sumptuous example of the Venetian Renaissance artisanship influenced by Middle Eastern style: its cover was made of gilded leather, painted with arabesque branches and buds and lastly lacquered. The scientific examination of the lavishly illuminated cover was performed before the book-binding conservation treatment, as the characterisation of the decoration materials allowed to plan an appropriate conservation project. The research first step has been the non-invasive observation of the cover surface by digital microscope through UV–VIS radiations. Then, the study of the composition of these materials has been carried out with ATR-FTIR spectroscopy, Raman spectroscopy, XRF spectroscopy and spot-test analyses on samples. Pigments like minium, green earth, a lead-based yellow and smalt have been detected in the painted layer, while a precise identification of the resins and varnishes layered on top of the decoration was not possible because of the heterogeneity of samples. Furthermore, the materials used for this cover can be usefully compared with those detected by other recent analyses carried out on a variety of 16th century Venetian book illuminations
Heat treatments effect on Cadophora luteo-olivacea of kiwifruit
Full text linkAbstract
Heat treatments represent alternative methods to fungicides to control latent fruit pathogens, such as Cadophora luteo-olivacea of kiwifruit. The study reports the efficacy of different hot water and hot air treatments (45 °, 50 °, 55 °, 65 °, and 70 °C with the duration respectively of 10, 15 and 20, 10, 65, 3 min) on the conidial and mycelial fungal isolates growth by in vitro assays. Both treatments at 70 °C were the most effective on the conidial and mycelial growth of C. luteo-olivacea isolates. On the mycelial growth, treatment efficacy was on average 88% and 71%, respectively, and on conidial growth by 100% and 91.3%. A significant reduction of xylanase and pectinase enzyme activities of the isolates was detected after hot water and air treatment (70 °C × 3 min). Both treatments showed, in most cases, the total reduction, sometimes variable with the target isolate. Hot air treatment was the most efficient treatment by reducing the skin pitting incidence in in vivo experiments, showing an efficacy of 46.6%, on average. Results show that heat treatments are effective against C. luteo-olivacea, but ‘time × temperature’ combinations remain the main challenge to develop
An in vitro study on dentin demineralization and remineralization: Collagen rearrangements and influence on the enucleated phase
No full textDentin remineralization is of clinical relevance in the therapy of caries and dentin hypersensitivity. This study is aimed at gaining more insights on a molecular scale, through IR spectroscopy, into dentin demineralization and remineralization. The dentin demineralization by ethylenediaminetetraacetic acid, EDTA (17%, 2 h) significantly altered the secondary structure distribution of collagen, upon loss of interaction with calcium ions. To investigate dentin remineralization, previously demineralized human dentin slices were soaked in Dulbecco's Phosphate Buffered Saline (DPBS) or Hank's Balanced Salt Solution HBSS, in close contact with three commercial cements used as sustained releasing sources of Ca2+ and OH− ions (i.e. calcium hydroxide- and calcium silicate-based cements). IR spectroscopy showed the occurrence of remineralization under these conditions. Collagen did not lose its ability to chelate Ca2+, and these interactions allowed collagen to rearrange into a conformation similar to that of sound dentin. This process appeared slower in HBSS than DPBS, as also shown by the lower degree of maturation of the inorganic phase enucleated in the former medium (amorphous calcium phosphate versus B-type carbonated apatite). Collagen appeared to act as a spatial constraint to crystal deposition, affecting crystallinity and carbonate content of the enucleated phase. Remineralization was found to strongly depend on the calcium releasing ability of the cements. The fast formation of a rough apatite biocoating may represent a favorable clinical condition in the context of mineralized tissue regeneration
Testing a bovine blood-derived compound as iron supply on Cucumis sativus L
Full text linkA new powder formulation obtained from bovine blood (Fe-heme) was tested on cucumber (Cucumis sativus L.) to investigate its effectiveness as iron supply in comparison with two synthetic iron-chelates fertilizers: ethylenediaminetetraacetic acid (EDTA/Fe3+) and ethylenediamine-N'N'-bis(2-hydroxyphenyl acetic acid) (o,oEDDHA/Fe3+). Green stressed cucumber plants were evaluated in their recovery (SPAD index and weight variations) and to test the iron reduction capacity of the roots at pH 7.5 and 6.0 using each iron treatment as iron supply. The blood-derived product showed similar effects on decreasing iron-deficiency symptoms: SPAD increments and the weights of plants were similar. Noteworthy, the average of Fe3+reduction capacity in roots was higher for EDTA/Fe3+, while it was similar for o,oEDDHA/Fe3+, and Fe-heme at pH 7.5. Fe-heme showed a complex behavior due to aggregation and low solubility at pH 6 and showed an unexpectedly high contribution of root exudates to iron reduction
INVESTMENT CASTING PROCESS: 3D TEMPERATURE MAP RECONSTRUCTION OF A CERAMIC SHELL MOLD
No full textThe purpose of this work is to experimentally reconstruct the 3D temperature map of a ceramic shell mold and to investigate its time-dependent thermal behavior during the final part of the investment casting process. The investment casting process is the most used technique to produce very reliable components. Nowadays, there are still too much failing processes that are unacceptable in terms of both plant downtime and material waste. These failing processes are mainly caused by a non-uniform cooling that can promote thermal gradients in the components leading to a generation of residual thermal stresses.
The experimental 3D temperature map reconstruction and its time-dependent behavior are analyzed through the Infrared Thermography technique. Such a reconstruction allows to observe the presence of strong temperature gradients and quantify them. In the present case, the central part of the investigated ceramic shell mold shows strong temperature gradient. This central part is of extreme importance because of the presence of the blades housings. The temperature difference present on the blades housings increases with time leading to stronger temperature gradient
INVESTMENT CASTING PROCESS: 3D TEMPERATURE MAP RECONSTRUCTION OF A CERAMIC SHELL MOLD
No full textThe purpose of this work is to experimentally reconstruct the 3D temperature map of a ceramic shell mold and to investigate its time-dependent thermal behavior during the final part of the investment casting process. The investment casting process is the most used technique to produce very reliable components. Nowadays, there are still too much failing processes that are unacceptable in terms of both plant downtime and material waste. These failing processes are mainly caused by a non-uniform cooling that can promote thermal gradients in the components leading to a generation of residual thermal stresses.
The experimental 3D temperature map reconstruction and its time-dependent behavior are analyzed through the Infrared Thermography technique. Such a reconstruction allows to observe the presence of strong temperature gradients and quantify them. In the present case, the central part of the investigated ceramic shell mold shows strong temperature gradient. This central part is of extreme importance because of the presence of the blades housings. The temperature difference present on the blades housings increases with time leading to stronger temperature gradient
Technical Feasibility of Laser Dissimilar Welding of Superalloys on Casted Nozzle Guide Vanes
No full textAn increasing degree of automation is required both in the automotive and aircraft industry in order to allow scrap reduction and flexibility. In this frame, the shift from arc welding to laser beam welding is being investigated for a number of applications on metals in aerospace engineering, where strict standards apply. In comparison with conventional welding methods, a number of advantages are benefited; nevertheless, when moving to a new technology, some issues must be addressed. Hence this study is aimed to investigate laser dissimilar welding of real metal components, in order to assess the technical feasibility as well as to discuss set-up and operating issues in view of the implementation of the process for actual industrial application. A second-stage stator of low-pressure turbine is considered: lightening of the airfoils of the nozzle guide vane is achieved thanks to inner hollows which are drained from wax upon casting; afterward, the core exits on the outer side of the nozzle must be conveniently closed off by means of metal plates. Joining of the plates to the nozzle is performed by fusion welding along the edge of each plate and a condition of dissimilar welding is in place, being the nozzle and the plates made of C1023 and Nimonic 75, respectively. A mixed factorial plan has been arranged, laser power, welding speed and focus position being the leading processing parameters; a convenient welding set-up is proposed. Reasons are given for the implementation of laser beam welding as an alternative to conventional arc welding
Prospecting algae and cyanobacteria as bioprotectans for plant disease control
No full textThe European Directive 2009/128 on sustainable use of pesticides promotes the use of alternative approaches
to synthetic products for plant disease control to reduce human, animals and environmental risks. Among
alternatives, natural products based on cyanobacteria and algae are gaining attention. Our studies demonstrated
that application of water extracts from Anabaena minutissima, Ecklonia maxima and Jania adhaerens
controlled powdery mildew caused by Podosphaera xanthii on cucumber detached cotyledons and seedlings
and induced the expression of PR genes related to plant-induced resistance. In addition, tomato seed treatment
with the same extracts increased germination, seedling dry weight, calibre, and reduced root rot caused by
Rhizoctonia solani on tomato plants. Seed treatment also increased chitinase activity and lignin compound
contents in tomato seedlings. A deeper investigation on the possible bioactive compounds of A. minutissima,
E. maxima and J. adhaerens, revealed the antifungal activity of polysaccharides against Botrytis cinerea, agent
of grey mould, in vitro and in vivo on strawberry fruits. Latest research pointed out that application of
phycobiliproteins from A. minutissima, Arthrospira platensis and Hydropuntia cornea on tomato fruits before
B. cinerea challenge reduced grey mould disease. In particular, FT-IR and FT-Raman spectroscopies have
shown that phycobiliproteins from A. minutissima preserved cutin and pectine structures of tomato fruit from
B. cinerea infection. In conclusion, our research demonstrate the potentialities of algae and cyanobacteria as a
bioprotectans for plant disease control
Cognitive Decision-making Systems for Scraps Control in Aerospace Turbine Blade Casting
No full textAbstractThe competitiveness of a casting system in modern lost wax production of superalloy turbine blades strongly depends on the reduction of scraps, which commonly affect superalloy cast parts. In order to achieve a focused goal of competitiveness, some key and vital parameters (Key Process Variables) have to be continuously taken under control to make very accurate predictions of Target Variables, which represent, as mapped KPVs domain, the ultimate performance of the entire production link.Such an approach is based on the development of robust control monitoring of the ceramic shell manufacture, which is specifically conceived to foster a possible reduction of scraps in the production if superalloy components. The concerned control will take into consideration data coming from both sensors and measured values in laboratory. The sensor data, which is originated from both new adopted inline and offline equipments at Europea Microfusioni Aerospaziali S.p.A. (EMA) and data measured in the EMA laboratories, will be merged into a sensor pattern vector which represents the basis to develop the EMA demonstrator within the Intelligent Fault Correction and self Optimizing manufacturing systems EU project funded in FP7. The sensor pattern vector will be used to feed an automatic system for the prediction of the process vital parameters. An automated system, based on artificial intelligence paradigms, in particular neural networks, will be fed with the data coming from the sensor pattern vector in order to produce an optimal multi-object output
Raman spectroscopy: a useful tool to probe protein structural changes
No full textRaman spectroscopy has become a versatile tool in protein science and biotechnology thanks to the improved instrument sensitivity which has increased the signal-to-noise ratio. Thus, this technique can be successfully used for determination of protein secondary structure, identification of metal coordination sites, hydrogen bonding, oxidation state and local environments of selected residues (i.e. Cys, Tyr, Trp), protein-ligand and -DNA interactions, etc. The advantages of this spectroscopic technique are its extreme sensitivity to changes in structure and molecular interaction and its non-destructive nature. In particular, in our lab, Raman spectroscopy has been recently used for obtaining structural information on changes induced by different stimuli:
• thermal aggregation: beta-lactoglobulin and bovine serum albumin;
• presence of metal ions: metallothioneins;
• adsorption of biomedical devices: self-assembling peptides;
• damages induced by radical stress: human serum albumin;
• thermal or chemical denaturation: lysozime
- …
