Light Magnetic Dark Matter in Direct Detection Searches

We study a fermionic Dark Matter particle carrying magnetic dipole moment and analyze its impact on direct detection experiments. In particular we show that it can accommodate the DAMA, CoGeNT and CRESST experimental results. Assuming conservative bounds, this candidate is shown not to be ruled out by the CDMS, XENON and PICASSO experiments. We offer an analytic understanding of how the long-range interaction modifies the experimental allowed regions, in the cross section versus Dark Matter mass parameter space, with respect to the typically assumed contact interaction. Finally, in the context of a symmetric Dark Matter sector, we determine the associated thermal relic density, and further provide relevant constraints imposed by indirect searches and colliders.Comment: 32 pages, 5+1 figures; v2: matches version published on JCAP, dipole-dipole interaction added, discussion on its magnitude added in appendix, few typos corrected and some references added, results strengthened. arXiv admin note: text overlap with arXiv:1108.466

Evaluation of the Stress State in Aluminium Foam Sandwiches

In this paper a discussion about the determination of the stress state corresponding to the application of four-points bending load on a sandwich panel having a core made of closed cell aluminium foam is reported. An analytical model based on laminated plate classical theory is compared to a more complex FEM model, considering the effect of geometric parameters of panels, like core and plate thickness, and of loading mode, like span length. The results show the difficulties to define a reliable model to calculate stress state in this kind of composite material

real time monitoring of damage evolution by nonlinear ultrasonic technique

Abstract In this work, the ultrasound technique was used to monitor the damage of material subjected to fatigue loads. Prediction of structural damage is critical for safe and reliable operation of engineered complex systems. In these measurements, conventional ultrasonic probes (transmitter and receiver) were stably fixed to the tested samples with steel brackets, in order to eliminate ever possible variability associated with the coupling of probes. The transmitted and received ultrasonic signals were recorded and analyzed using a digital oscilloscope. The data were converted into the frequency domain using an algorithm developed in Matlab based on Fast Fourier Transform (FFT) for received signal in dependence of the applied stress level and the accumulated fatigue damage was deeply studied in order to recognize quantitative effects, suitable for an experimental prediction of the integrity of the material. The acquired data were compared with the reference signal, at the beginning of the fatigue tests. Particular care has been paid to UT signal attenuation and to the study of the frequency spectrum as the number of load cycles varies. The applied experimental technique has proved efficient for detecting damage induced by mechanical stress

Preliminary study about the detection of perfluoroalkyl substances in eel samples of Lake Garda by liquid chromatography tandem mass high resolution mass spectrometry (LC-HRMS).

Perfluoroalkyl substances (PFASs) are a large class of fluorinated aliphatic chemical of anthropogenic origin with high chemical stability even at high temperatures and in presence of alkalis, strong acids or oxidizing agents (Lau et al. 2004). All these characteristics make them no biodegradable and very persistent in the environment, associated with adverse health risks (Eriksen et al. 2010). Food, especially fish and other seafood, is considered the main source of exposure to PFASs (EFSA 2012). In this preliminary study we developed and validated a sensitive, selective and specific method by LC-HRMS Orbitrap to monitor the presence of 16 PFASs in eel (Anguilla Anguilla) samples. The clean-up of the lyophilized samples consisted of a previous extraction step with acetonitrile to precipitate also proteins, followed by a purification step through Oasis® WAX SPE (Weak Anionic Exchange Solid Phase Extraction) cartridges. The method applied to 45 farmed eel samples from Lake Garda showed the presence of several PFASs, up to 10 in the same eel, in the order of ng/g (Fig.1). The results provided a representative situation of the  PFASs contamination level of the lake, lower than those of others European countries (Hoff et al. 2005, Kwadijk et al. 2010)

Detection of seven β2-agonists in teeth by LC-MS/MS: preliminary results.

β2-agonists are powerful tocolytic (the only use permitted in cattle) and bronchodilator agents, butmay also be administered as growth promoters to improve the production of lean meat increasing alsothe lipolytic activity. Although the European Union (EU), China and other Asian countries have bannedthe use of β2-agonists for growth promoting purposes (European Union, 2003), the United States ofAmerica (USA) authorised ractopamine as a feed additive for swine, cattle and turkey. These veterinarydrugs, generally show high clearance rates in the conventional biological matrices, as well as urine, liverand muscle, making difficult their detection (Wu, 2014). For this reason, we suggested bovine teeth asa new unconventional matrix of accumulation in a more long-time window, for the detection ofcimaterol, clenbuterol, isoxsuprine, mabuterol, ractopamine, salbutamol and terbutaline. In literature,the few studies on teeth are limited to human (Andra, 2015) and are absent for veterinary medicine.The samples extracted by a simple liquid extraction step with ethyl acetate:tert-butyl methyl ether (4:1,v/v) after washing and pulverization of teeth, through a ball mill, were analysed using a liquidchromatography tandem mass spectrometry (LC-MS/MS) confirmatory method validated according tothe Commission Decision 2002/657/EC criteria (European Union, 2002). Teeth from 8 veal calves,administered per os with 80 mg day-1 oral ractopamine for 32 days, and from seven random bovinesfrom the food chain were collected at the slaughterhouse to test the suitability of this matrix. Theresults demonstrated ractopamine presence in teeth from the treated animals (average concentration8.90 ng g-1). Isoxsuprine was found in a control sample (13.67 ng g-1), demonstrating the effectivenessof this matrix as a powerful tool to ensure illegal treatment

Mechanical and microstructural behaviour of 2024–7075 aluminium alloy sheets joined by friction stir welding

The aim of the present work is to investigate on the mechanical and microstructural properties of dissimilar 2024 and 7075 aluminium sheets joined by friction stir welding (FSW). The two sheets, aligned with perpendicular rolling directions, have been successfully welded; successively, the welded sheets have been tested under tension at room temperature in order to analyse the mechanical response with respect to the parent materials. The fatigue endurance (S–N) curves of the welded joints have been achieved, since the fatigue behaviour of light welded sheets is the best performance indicator for a large part of industrial applications; a resonant electro-mechanical testing machine load and a constant load ratio RZsmin/smaxZ0.1 have been used at a load frequency of about 75 Hz. The resulted microstructure due to the FSW process has been studied by employing optical and scanning electron microscopy either on ‘as welded’ specimens and on tested specimen after rupture occurred

MATHICSE Technical Report : A multi level Monte Carlo method with control variate for elliptic PDEs with log-normal coefficients

We consider the numerical approximation of the stochastic Darcy problem with log-normal permeability field and propose a novel Multi Level Monte Carlo approach with a control variate variance reduction technique on each level. We model the log-permeability as a stationary Gaussian random field with a covariance function belonging to the so called Matérn family, which includes both fields with very limited and very high spatial regularity. The control variate is obtained starting from the solution of an auxiliary problem with smoothed permeability coefficient and its expected value is effectively computed with a Stochastic Collocation method on the finest level in which the control variate is applied. We analyze the variance reduction induced by the control variate, and the total mean square error of the new estimator. To conclude we present some numerical examples and a comparison with the standard Multi Level Monte Carlo method, which shows the effectiveness of the proposed method

Detection of boldenone, its sulfate and glucuronate forms, androstadienedione, cortisol, cortisone, prednisolone, prednisone and dexamethasone in bovine bile and urine by LC-MS/MS: preliminary results.

The European Union regulations ban or regulate the use of substances with hormonal action. There are, however, some detectable steroids in biological matrices from cattle to which no administration were made. These are the so called “grey-zone” or “pseudoendogenous” substances (endogenously produced under certain circumstances). The administration of boldenone and androstadienedione to cattle is forbidden both for therapeutic or growth promotion purposes, while therapeutic use of prednisolone is permitted. The control of the use of these substances is hampered by their pseudoendogenous nature. We made a comparison between analyses performed on the classical matrix urine with bile (a novel matrix) from the same animals, with the aim to determine the better matrix for the above mentioned steroids. We tested the synthetic corticosteroid dexamethasone, too. The preliminary results do not show any difference between the two matrices, as concern the pseudoendogenous substances. The data about dexamethasone were instead very promising about the use of bile. The detection frequency and concentration levels were, in fact, higher in bile than in urine from the same animals

Comparative analysis of digital models from 3D photogrammetry and structured light scanning for the study of tetrapod tracks

The present work aims at analyzing the acquisition capacity of different digital reconstruction techniques for three-dimensional models, in the frame of the study of the remarkable Middle Triassic (Ladinic) tetrapod ichnoassemblage from the Quarziti del Monte Serra Formation (Monti Pisani, Tuscany, central Italy). Tracks stored in different Italian museum collections were processed and analyzed through two different digital acquisition methodologies, namely, digital photogrammetry and structured light scanning (with the EinScan Pro HD scanner model, capable of a maximum resolution of 0.2 mm) to evaluate which of these techniques is most suitable for the study of small- to medium-sized tetrapod tracks. Two models were created for each sample, one for each acquisition methodology. These models were processed using the software Meshmixer, Meshlab and CloudCompare, to locate any possible error in the mesh, correct them and compare the models with each other in terms of quality and graphical rendering, respectively. The RStudio software was also used to verify and control, by using statistical tests, the normal distribution of the data, as well as to further process them. We noticed that the average number of triangles is higher for the meshes obtained via photogrammetry; likewise, the values of the metric “Per Face Quality according to triangle shape and aspect ratio – Mean ratio of triangle”, available on Meshlab and used here to evaluate the quality of a mesh, is higher. Photogrammetry is thus preferable in the study of centimetric tracks as it allows for very high levels of mesh detail. That said, more experience and a deeper understanding of the acquisition process by the operator are needed for fruitfully exploiting the full potentialities of photogrammetr