New version of PLNoise: a package for exact numerical simulation of power-law noises

In a recent paper I have introduced a package for the exact simulation of power-law noises and other colored noises [E. Milotti, Comput. Phys. Comm. 175 (2006) 212]: in particular, the algorithm generates 1/fα noises with 0<α?2. Here I extend the algorithm to generate 1/fα noises with 2<α?4 (black noises). The method is exact in the sense that it produces a sampled process with a theoretically guaranteed range-limited power-law spectrum for any arbitrary sequence of sampling intervals, i.e. the sampling times may be unevenly spaced.

Program summary

Title of program: PLNoiseCatalogue identifier:ADXV_v2_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXV_v2_0.htmlLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandProgramming language used: ANSI CComputer: Any computer with an ANSI C compiler: the package has been tested with gcc version 3.2.3 on Red Hat Linux 3.2.3-52 and gcc version 4.0.0 and 4.0.1 on Apple Mac OS X-10.4Operating system: All operating systems capable of running an ANSI C compilerRAM: The code of the test program is very compact (about 60 Kbytes), but the program works with list management and allocates memory dynamically; in a typical run with average list length 2⋅¹⁰⁴, the RAM taken by the list is 200 KbytesExternal routines: The package needs external routines to generate uniform and exponential deviates. The implementation described here uses the random number generation library ranlib freely available from Netlib [B.W. Brown, J. Lovato, K. Russell: ranlib, available from Netlib, http://www.netlib.org/random/index.html, select the C version ranlib.c], but it has also been successfully tested with the random number routines in Numerical Recipes [W.H. Press, S.A. Teulkolsky, W.T. Vetterling, B.P. Flannery, Numerical Recipes in C: The Art of Scientific Computing, second ed., Cambridge Univ. Press., Cambridge, 1992, pp. 274-290]. Notice that ranlib requires a pair of routines from the linear algebra package LINPACK, and that the distribution of ranlib includes the C source of these routines, in case LINPACK is not installed on the target machine.No. of lines in distributed program, including test data, etc.:2975No. of bytes in distributed program, including test data, etc.:194 588Distribution format:tar.gzCatalogue identifier of previous version: ADXV_v1_0Journal reference of previous version: Comput. Phys. Comm. 175 (2006) 212Does the new version supersede the previous version?: YesNature of problem: Exact generation of different types of colored noise.Solution method: Random superposition of relaxation processes [E. Milotti, Phys. Rev. E 72 (2005) 056701], possibly followed by an integration step to produce noise with spectral index >2.Reasons for the new version: Extension to 1/fα noises with spectral index 2<α?4: the new version generates both noises with spectral with spectral index 0<α?2 and with 2<α?4.Summary of revisions: Although the overall structure remains the same, one routine has been added and several changes have been made throughout the code to include the new integration step.Unusual features: The algorithm is theoretically guaranteed to be exact, and unlike all other existing generators it can generate samples with uneven spacing.Additional comments: The program requires an initialization step; for some parameter sets this may become rather heavy.Running time: Running time varies widely with different input parameters, however in a test run like the one in Section 3 in the long write-up, the generation routine took on average about 75 μs for each sample.     

TREND OF ATMOSPHERIC BENZO[ a ]PYRENE IN ITALY BEFORE THE ADOPTION OF THE EUROPEAN DIRECTIVE ON PAHs

The benzo[a]pyrene temporal trend was investigated in 11 towns where at least five annual means were available. The overall number of stations was 22, of which 12 were traffic-oriented, 6 background and 4 industrial. The trend was generally declining at traffic-oriented sites and roughly stable at background sites. The annual means in 2004 still exceeded the forthcoming European target value of 1 ng/m ³ in two towns (up to 1.9 ng/m ³ ). The background means (up to 1.4 ng/m ³ in 2004) accounted for approximately 40–90% of those at the traffic-oriented sites in the same town. The presence of a coke plant was incompatible with the attainment of the target value, while the adoption of technical measures on a carbon electrode plant was successful in attaining concentrations lower than the target value. In heavy traffic areas in Italy, the attainment of the target value hardly appears feasible under the current conditions of traffic congestion.     

Evaluation of a fluid versus a powder pepsin formulation to detect Trichinella spiralis larvae in meat samples by a digestion technique

Pepsin powder constitutes a health risk, potentially causing severe allergic reactions to those handling the chemical. A fluid pepsin formulation was produced and tested, first in a preliminary study and then in a ring trial encompassing four European National Reference Laboratories (NRLs). The purpose of each trial was to ascertain and compare the action of pepsin powder with that of the pepsin fluid for digesting meat and liberating encapsulated Trichinella spiralis larvae for subsequent counting. The quality of digestion was furthermore evaluated by assessing the visibility through the digestion fluid and the amount of debris remaining after digestion. For the ring trial, at each laboratory 20 blinded replicate 100-g samples of pork meat containing a known number of encapsulated T. spiralis larvae (0 to 30) were digested by the magnetic stirrer method using either the standard pepsin powder (10 samples) or the pepsin fluid (10 samples). With an average recovery rate of 70 to 80%, all NRLs found the pepsin fluid and pepsin powder to be equally effective. The NRLs also found no difference between the two pepsin formulations with regard to debris remnants or visibility through the digestion fluid. The use of pepsin fluid may therefore constitute an improvement of the digestion procedure for the analysts involved.     

Rigid body water impact-experimental tests and numerical simulations using the SPH method

Statistics show that water impact of an aircraft in emergency is likely to have tragic consequences and therefore new researches on this topic are recommendable. In 2005, the GARTEUR AG15 was established to improve the SPH method for application to helicopter ditching. As a contribution, water impact drop tests using rigid bodies were performed at the Politecnico di Milano LAST Crash Lab to collect data and validate the numerical models. During the tests, impact decelerations were measured and suitably pressure transducers were developed to measure the impact pressures. Numerical simulations were carried out by adopting the SPH method to model the fluid region. A close experimental-numerical correlation was obtained. Findings are reported and guidelines for further investigations are proposed.     

Unified theory for confinement of RC solid and hollow circular columns

Hollow bridge piers are incorporated in tall bridges to maximize the structural efficiency of the strength-mass and stiffness-mass ratios. Column jacketing with fiber reinforced polymer (FRP) composite materials has been extensively studied in recent years but it is uncertain how FRP jackets may perform when retrofitting hollow concrete columns since the topic has been little researched.A confinement model for circular hollow sections is proposed which can be extended to the case of solid sections. The model is able to estimate confinement effectiveness and to plot stress–strain relationships, which are different in the case of solid and hollow sections.     

Control of acidity development on solid sulfur due to bacterial action

The global production of sulfur, which is currently obtained almost exclusively as an involuntary byproduct of the oil and gas industry, is exceeding the market demand so that long term storage or even definitive disposal of elemental sulfur is often needed to handle production surplus. The storage of large quantities of elemental sulfur calls for solidifying liquid sulfur in huge blocks, hundred meters wide on each side and as high as 20 meters. Sulfur, in presence of water and air, can be oxidized to sulfuric acid by a ubiquitous microorganism: Thiobacillus. On large blocks, this natural phenomenon may lead to soil and water acidification. Research projects have addressed suppression of Thiobacilli activity to prevent acidification, but no industrial applications have been reported. This work describes the inhibition of sulfur biological oxidation attainable by exposing sulfur to a high ionic strength environment. The bacteriostatic action is produced by contacting sulfur with a solution of an inorganic salt, such as sodium chloride, having an ionic strength similar to sea water. Possible ways to exploit the inhibitory effect to prevent the generation of acidity from sulfur storage blocks are suggested.     

跻身第三代半导体市场ST助力全球碳中和

随着第三代半导体的工艺越来越成熟和稳定,应用在工业和电动汽车上的产品也变得多样化.作为半导体行业中的佼佼者,意法半导体同样重视第三代半导体带来的优势作用,推出了有关氮化镓(GaN)和碳化硅(SiC)的一系列产品,有力地推动了第三代半导体在电动汽车和工业领域上的应用发展.     

Micro-tomographic characterization of composite recycled glass-silicone foams for applications in civil engineering

Noninvasive X-ray micro-computed tomography was applied for a complete quantitative and qualitative analysis of the cellular structure of composite foams constituted by a silicone matrix and a glass production waste filler. Composite foams with different glass filler weight content in the range 0–80% were synthesized and characterized. The tomographic analysis was employed in order to assess the structural heterogeneities, void fraction values, and bubble size distribution for all composite foams. The 3D micro-CT images analysis, performed at different cross-sections, highlighted heterogeneous cell growth or more elongated cells in the case of low and high filler content foams, respectively. Batch with 60% of glass filler was identified as a composite foam with effective void fraction values and relatively uniform spheroidal cellular structure (average sphericity 0.723 and diameter 0.107 mm). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48718.     

Pull-off adhesion of hybrid glass-steel adhesive joints in salt fog environment

The aim of this paper was to evaluate the durability behaviour of glass/steel adhesive joints exposed to salt fog environmental conditions for ten weeks, according to ASTM B117 standard. To this scope, pull-off mechanical tests were carried out in order to evaluate the performances evolution and damage phenomena of the adhesive joints during the ageing exposition. Two different types of adhesives were compared (i.e. epoxy and polyurethane ones). Moreover, the effects of the glass surface condition and the presence of a basalt mat layer within the adhesive thickness were evaluated. The mechanical performances were related with the occurred failure mechanisms. Epoxy-based joints showed higher strength and durability than the polyurethane based ones. Furthermore, frosted glass surface condition and basalt interlayer addition enhanced mechanical durability in salt fog environment of glass–metal dissimilar joints.     

Nanostructured biomaterials for tissue engineered bone tissue reconstruction

Bone tissue engineering strategies are emerging as attractive alternatives to autografts and allografts in bone tissue reconstruction, in particular thanks to their association with nanotechnologies. Nanostructured biomaterials, indeed, mimic the extracellular matrix (ECM) of the natural bone, creating an artificial microenvironment that promotes cell adhesion, proliferation and differentiation. At the same time, the possibility to easily isolate mesenchymal stem cells (MSCs) from different adult tissues together with their multi-lineage differentiation potential makes them an interesting tool in the field of bone tissue engineering. This review gives an overview of the most promising nanostructured biomaterials, used alone or in combination with MSCs, which could in future be employed as bone substitutes. Recent works indicate that composite scaffolds made of ceramics/metals or ceramics/polymers are undoubtedly more effective than the single counterparts in terms of osteoconductivity, osteogenicity and osteoinductivity. A better understanding of the interactions between MSCs and nanostructured biomaterials will surely contribute to the progress of bone tissue engineering.