The Differential System Method for the Identification of Transmissivity and Storativity

The differential system (DS) method for the identification of transmissivity and storativity is applied to a confined isotropic aquifer in transient conditions. The data that are required for the identification are the piezometric heads and the source terms, together with the value of transmissivity at a single point only, which is the only parameter value needed a priori. In particular, no a priori knowledge of storativity is needed and, moreover, the identification of transmissivity does not depend upon storativity. The DS method yields the internode transmissivities necessary for the conservative finite differences models in a natural way, because it identifies transmissivities along the internodal segments, so that a well-known formula can be applied that bypasses the difficulty of finding an equivalent cell transmissivity and an averaging scheme. In addition, the DS method takes into account several different flows all over the aquifer, so that the identified parameters are to a certain degree global andflow independent. Moreover, the method allows for a piecemeal identification of the parameters, thus keeping away from the regions where wells are pumping so that a two-dimensional model can be used throughout. We test the applicability of the DS method with noisy data by means of numerical synthetic examples and compare the identified internode transmissivities with the reference values. We use the identified parameters to forecast the behaviour of the aquifer under different exploitation and boundary conditions and we compare the forecast piezometric heads, their gradients and the associated fluxes with those computed with the reference parameters.     

A chemical view onto post-consumer poly(ethylene terephthalate) valorization through reactive blending with functionalized polyolefins

The recovery of poly(ethylene terephthalate) from post-consumer packaging products, such as beverage bottles, allowed to obtain flakes with a purity level suitable for reprocessing. Among many possibilities, the blending with polyolefins can provide toughened materials but, as poly(ethylene terephthalate) and polyolefins are immiscible, different methods of reactive compatibilization were followed to achieve a fine dispersion of polyolefln domains into a poly(ethylene terephthalate) matrix. In this meanwhile the use of a functionalized polyolefin, bearing reactive groups toward poly(ethylene terephthalate) terminals, is a promising route to obtain grafted copolymers acting as interface stabilizers. In particular, the use in the melt blending of ester or hydroxyl functionalized polyolefins in the presence of transesterification catalysts and/or anhydride functionalized polyolefins as compatibilizer precursors were both investigated by focusing onto chemical aspects. The prepared blends were analyzed through suitable fractionation methods, such as selective extractions, and spectroscopic analysis in order to identify the molecular architecture of the macromolecules resulting from the process and study their effectiveness at the interface region. Moreover the phase morphology and the thermo-mechanical properties were investigated and correlated to the structure of the macromolecular species in the system.     

Determination of antioxidant capacity of papaya fruit and papaya-based food and drug integrators, using a biosensor device and other analytical methods

Abstract  

Antioxidant and radical-scavenging properties are alleged to form the basis of the therapeutic properties attributed to the papaya and papaya-based food and drug integrators that have recently appeared on the market. In the present research a biosensor-based method was used to determine the antioxidant capacity of papaya fruit as is, that of several food and drug integrators, and lastly of pure papain alone. Results are compared using a reference spectrofluorimetric method and two other spectrophotometric methods. In addition pro-oxidant properties of the same samples were also checked using two colorimetric methods.     

Determination of antioxidant capacity of papaya fruit and papaya-based food and drug integrators,using a biosensor device and other analytical methods

Abstract  Antioxidant and radical-scavenging properties are alleged to form the basis of the therapeutic properties attributed to the papaya and papaya-based food and drug integrators that have recently appeared on the market. In the present research a biosensor-based method was used to determine the antioxidant capacity of papaya fruit as is, that of several food and drug integrators, and lastly of pure papain alone. Results are compared using a reference spectrofluorimetric method and two other spectrophotometric methods. In addition pro-oxidant properties of the same samples were also checked using two colorimetric methods. Graphical abstract       

Cyclam‐Cored Dendrimers Appended with Four Dendrons of Two Different Types: Intradendrimer Energy Transfer

We have synthesized two cyclam‐cored dendrimers appended with dendrons of two different types by proper protection/deprotection of the cyclam unit. The resulting dendrimers contain six naphthyl and two dansyl units ( N6 D2 ) or two dansyl and six naphthyl units ( N2 D6 ) at the periphery. Their photophysical properties have been compared to those of a dendrimer containing 8 dansyl units ( D8 ) and a previously investigated dendrimer containing 8 naphthyl units ( N8 ). The absorption spectra are those expected on the basis of the number of chromophores, demonstrating that no ground state interaction takes place. The emission spectra of N2 D6 and N6 D2 show naphthalene localized and naphthalene excimer emission similar to those observed in the case of N8 , together with a much stronger dansyl emission with maximum at 525 nm. Addition of CF₃SO₃H to dendrimer solutions in CH₃CN/CH₂Cl₂ 1:1 (v/v) leads to protonation of the aliphatic amine units of the cyclam core at first and then of the aromatic amine of each dansyl chromophores. Cyclam can be diprotonated and this affects dansyl absorption and, most significantly, emission bands by a charge perturbation effect. Each dansyl unit is independently protonated in both dendrimers. The most interesting photophysical feature of these heterofunctionalized cyclam‐cored dendrimers is the occurrence of an intradendrimer photoinduced energy transfer from naphthyl to dansyl chromophores of two different dendrons (interdendron mechanism). The efficiency of this process is 50 % for N6 D2 and it can be increased up to 75 % upon protonation of the cyclam core and formation of N6 D2 (2H⁺). This arises from the fact that protonation of the amine units of the cyclam prevents formation of exciplexes upon naphthyl excitation, thus shutting down one of the deactivation processes of the fluorescent naphthyl excited state.     

Modifications of the mesoscopic structure of cellulose in paper degradation

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.     

Paleodiet characterisation of an Etrurian population of Pontecagnano (Italy) by Isotope Ratio Mass Spectrometry (IRMS) and Atomic Absorption Spectrometry (AAS)(#)

Human bones recovered from the archaeological site of Pontecagnano (Salerno, Italy) have been studied to reconstruct the diet of an Etrurian population. Two different areas were investigated, named Library and Sant' Antonio, with a total of 44 tombs containing human skeletal remains, ranging in age from the 8th to the 3rd century B.C. This time span was confirmed by 14C dating obtained using Accelerator Mass Spectrometry (AMS) on one bone sample from each site.Atomic Absorption Spectrometry (AAS) was used to extract information about the concentration of Sr, Zn, Ca elements in the bone inorganic fraction, whilst stable isotope ratio measurements (IRMS) were carried out on bone collagen to obtain the delta13C and delta15N. A reliable technique has been used to extract and separate the inorganic and organic fractions of the bone remains.Both IRMS and AAS results suggest a mixed diet including C3 plant food and herbivore animals, consistent with archaeological indications.     

Diastereoselective sulfonate-directed carbonyl reduction of γ-keto-sulfonates

The diastereoselective reduction of γ-keto-sulfonates to afford α,γ-substituted γ-hydroxy sulfonates has been investigated. Herein we report the first example of a diastereoselective carbonyl reduction whereby hydride attack is directed via chelation of a neighbouring sulfonate group to a boron atom, thus affording prevalently trans γ-hydroxy sulfonates.