A Nontraditional Laboratory Proposal: Investigating the Kinetics of a Chemical Reaction

This paper presents an unstructured laboratory in which students determine the rate law for a reaction. We have selected for this investigation the reaction between magnesium and hydrochloric acid. The general goal of the proposal is threefold: (1) to increase students interest in science during first-year chemistry; (2) to create a more active learning environment where students can learn and do science as scientists; and (3) to develop and promote critical thinking, analytical reasoning, collaboration, and interactive discussion based on a scientific problem. This laboratory has proven to be effective because the students, with some guidance from the instructor, were able to (1) state one or more hypotheses related to the problem under study (chemical kinetics); (2) design procedures and strategies to answer specific questions; and (3) establish methods to manipulate and interpret the data. Finally, the students were required to write a report. In this way, the laboratory promotes creativity and improves students critical thinking in an introductory course of university general chemistry.     

Substitution of fish species detected by thin-layer isoelectric focusing and a computer-assisted method for the evaluation of gels

Fourteen fish species susceptible to substitution were analysed by the thin-layer isoelectric focusing technique on polyacrylamide gels of pH 3.5–9.5. Four fish per species were run on the same gel to verify the possibility to differentiate them according to their protein banding patterns. The occurrence of intraspecific differences due either to electrophoretic variations or to protein polymorphism was also observed. In fact, some of them showed few dissimilarities among their protein profiles. However, the differentiation was possible for all species, even for those belonging to the same order, family and genus. Computer-based tools combined with statistical analysis were implemented and usefully applied to avoid a subjective evaluation of the isoelectric focusing gels, and to verify the reliability of the preliminary visual comparison of protein patterns.     

Violacein/β-Cyclodextrin Inclusion Complex Formation Studied by Measurements of Diffusion Coefficient and Circular Dichroism

The formation of inclusion compounds between violacein and-cyclodextrin was studied by diffusion and circulardichroism measurements. The present work was undertaken to explore the feasibilityof the -cyclodextrin in reducing the toxicity and enhancing the antitumoral efficacy ofviolacein by forming an inclusion complex. The results of the two experimentsare in good agreement, suggesting the formation of 1 : 1 and 1 : 2 complexes.The diffusion coefficient measurements enabled estimates of the sizes of the complexesinvolved. From the circular dichroism and computational calculations it was possibleto view a preference for inclusion of the most polar part of the molecule to form a1 : 2 inclusion complex. We expect that this work proves the potential of thesetechniques to determining complex stoichiometry.     

Thermal treatments and characterizations of pellets for SPES direct target

In this work targets of graphite-rich lanthanum dicarbide have been produced through carburization and sintering of suitable precursor pellets obtained by mixing and pressing lanthanum oxide and graphite powders. The results about the control of the production process and the investigation of the physical properties of the pellets, performed respectively through thermal analyses (TG/DTA) and X-ray diffraction (XRD), are reported and discussed.     

An adaptive line-by-line—statistical model for fast and accurate spectral simulations in low-pressure plasmas

An adaptive grid method is proposed for the simulation of low-pressure plasma radiation. The method relies on two complementary approaches which significantly reduce calculation times and the size of the obtained grids: Weak lines are calculated as a so-called “pseudo-continuum”, hence reducing the number of calculated lines, and a numerical algorithm has been developed for accurately calculating Voigt lineshapes using a minimum number of points. The method is fully user-parametric, allowing the choice of privileging calculation efficiency, or alternatively privileging the accuracy of the computed spectra. Sample radiative transfer calculations are presented, which show the efficiency of the method, also providing some guidelines on how to define lineshape calculation parameters, depending on the problem to be solved.     

The SPES direct UCx target

A possible solution for a target system aimed at the production of exotic nuclei as a result of high energy fissions in ²³⁸U compounds has been analyzed. The proposed configuration is constituted by a primary proton beam (40 MeV, 0.2 mA) directly impinging on uranium carbide disks inserted within a cylindrical carbon box. This system has been conceived to obtain both a high number of neutron rich atoms (originated from about 10¹³ fissions/s) and a low power deposition in the target. In order to extract the fission fragments, the box has to be hold at 2000^○C. The thermal analysis shows the capability of the thermal radiation to cool the disks with a reasonable margin below the material melting point. Moreover, the analyses of the thermo-mechanical behaviour and of the effusion times confirm the promising features of this target configuration.     

On Some Operators Associated to Superoscillations

In this paper we study the convergence of some sequences of operators associated to the Aharonov and Berry’s superoscillating functions. The main tool to define the sequences of operators is the spectral theorem. In particular we discuss the case of sequences of unbounded self-adjoint operators on a Hilbert space. We apply our results to the case where T is the self-adjoint extension of the momentum operator with unbounded spectrum.     

Hyperbolic Balance Laws with a Non Local Source

This paper is devoted to hyperbolic systems of balance laws with non local source terms. The existence, uniqueness and Lipschitz dependence proved here comprise previous results in the literature and can be applied to physical models, such as Euler system for a radiating gas and Rosenau regularization of the Chapman–Enskog expansion.