A comparative study on mother wavelet selection in ultrasound image denoising

The purpose of this work is to evaluate how the choice of mother wavelet function affects ultrasound image denoising. The paper presents a detailed analysis of the properties of each wavelet family highlighting their properties and limitations in ultrasound image filtering applications.     

A library of tunable agarose carbomer‐based hydrogels for tissue engineering applications: The role of cross‐linkers

The role of the crosslinking agents was studied for a series of agarose–carbomer‐based hydrogels, specifically developed for tissue engineering applications, and was quantified using the most typical polycondensation parameter; the ratio between the reacting moieties, i.e., hydroxyl (A) and carboxyl (B) groups. Because of the bonds among hydrophilic groups, as A/B ratio was increased, the gel network showed higher compactness and less ability to swell. The role of crosslinkers was also further analyzed using environmental scanning electron microscopy (E/SEM) and rheological measurements. SEM analysis underlined the presence of different structures as well as the erosion due to the presence of cosolvents in hydrogel synthesis. Rheological measurements showed the dependence of crossover strain value and yield stress upon the ratio of hydroxyl/carboxyl groups and, generally, a clear pseudoplastic behavior. Such detailed characterizations were essential to investigate the design of an optimized formulation capable of being a proper hosting environment for glial cells, which were here used as they are a promising cell type in several central nervous system repair strategies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123:2211–2221, 2012     

Are web applications more defect-prone than desktop applications?

A lot of effort in the literature has been devoted to define and validate fault taxonomies and models related to different domains, e.g. Service-oriented and Web systems, and properties, e.g. software quality and security. Nevertheless, few attempts were carried out to understand the specific nature of Web bugs and their distribution among the layers of a typical application’s architecture—presentation layer, business logic and data logic. In this paper, we present an experimental investigation aimed at studying the distribution of bugs among different layers of Web and Desktop applications. The experiment follows a well-defined procedure executed by six bachelor students. Overall, the analysis considers 1,472 bugs belonging to 20 different applications. The experimental study provides strong evidence that the presentation layer in Web applications is more defect-prone than the analogous layer in Desktop applications. An additional factor influencing the distribution of defects is represented by the application domain.     

Influence of metallic and oxidized iron/steel on the reactivity of triphenyl phosphorothionate in oil solution

The influence of metallic and oxidized iron/steel on the reactivity of triphenyl phosphorothionate (TPPT) in oil solution at 473 K was investigated by means of FT-IR, NMR and XPS. The FT-IR and NMR results show that the degradation of TPPT was catalyzed by metallic and oxidized iron powder and started with the breakage of the PS bond to form triphenyl phosphate (TPP). The results of the XPS sputter depth profile show the multilayer structure of the thermal film formed on 100Cr6 steel filings immersed for 72 h in TPPT solution heated at 473 K.     

Metal ion adsorption by Phomopsis sp. biomaterial in laboratory experiments and real wastewater treatments

An insoluble material of polysaccharidic nature has been obtained by thermal alkali treatment of the filamentous fungus Phomopsis sp. FT-IR spectrum of the resulting material as well as its nitrogen content suggest that chitosan and glucans are the main components of the biomaterial. Information on Lewis base sites has also been obtained and used as a guideline in the evaluation of the complexing ability against a number of metal ions in aqueous media at pH in the range 4--6. Results indicate that after 24h contact time, up to 870 micromol/g of lead, 390 micromol/g of copper, 230 micromol/g of cadmium, 150 micromol/g of zinc and 110 micromol/g of nickel ions are adsorbed into the material. After approximately 10 min, about 70% of the overall adsorption process has already been completed. Adsorbed metal ions can be recovered by washing with dilute acid. Experiments have been extended to a real wastewater effluent confirming the potential of this biomaterial as a depolluting agent.     

Effect of Pitch and Roll Static Angle on Lubricant Transfer Between Disk and Slider

A precision spin stand was used to study the effects of pitch static angle and roll static angle on lubricant transfer between a disk and a slider in a hard disk drive. The lubricant distribution on the slider was determined by time-of-flight secondary ion mass spectrometry, while the lubricant distribution on the disks was obtained using optical surface analysis. Lubricant transfer from the disk to the slider was found to increase as a function of the pitch static angle of the slider. Negative roll static angles were found to have a larger effect on lubricant transfer and the formation of lubricant moguls than positive roll static angles. Suspension frequencies and pitch mode frequencies were observed in the lubricant mogul patterns for negative roll static angles.     

High accuracy wavelength calibration for a scanning visible spectrometer

Spectroscopic applications for plasma velocity measurements often require wavelength accuracies ≤0.2?A?. An automated calibration, which is stable over time and environmental conditions without the need to recalibrate after each grating movement, was developed for a scanning spectrometer to achieve high wavelength accuracy over the visible spectrum. This method fits all relevant spectrometer parameters using multiple calibration spectra. With a stepping-motor controlled sine drive, an accuracy of ～0.25?A? has been demonstrated. With the addition of a high resolution (0.075?arc sec) optical encoder on the grating stage, greater precision (～0.005?A?) is possible, allowing absolute velocity measurements within ～0.3?km/s. This level of precision requires monitoring of atmospheric temperature and pressure and of grating bulk temperature to correct for changes in the refractive index of air and the groove density, respectively.