Improved copper–epoxy adhesion by laser micro- and nano-structuring of copper surface for thermal applications

The objective of this work is the enhancement of metal-to-metal bonding to provide high thermal conductivity together with electrical insulation, to be used as heat sinks at room and cryo-genic temperatures. High thermal conductive metal (copper) and epoxy resin (Stycast 2850FT) were used in this study, with the latter also providing the required electrical insulation. The copper surface was irradiated with laser to induce micro- and nano-patterned structures that result in an improvement of the adhesion between the epoxy and the copper. Thus, copper-to-copper bonding strength was characterized by means of mechanical tensile shear tests. The effect of the laser processing on the thermal conductivity properties of the Cu/epoxy/Cu joint at different temperatures, from 10 to 300 K, is also reported. Using adequate laser parameters, it is possible to obtain high bonding strength values limited by cohesive epoxy fracture, together with good thermal conductivity at ambient and cryogenic temperatures. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Midiendo el diámetro de la tierra

De distintas maneras se han ingeniado interesantes procedimientos para medir el radio de la tierra. Aquí se expone uno con la utilización de muchas técnicas sea formales o no para tal fín. El procedimiento es lo suficientemente sencillo como para que cualquier aficionado pueda repetirlo. No es un nuevo método, pero puede verse como pequeñas variaciones al mismo pudieran dar menos o más errores. El método precisa de tres piedras, una cuerda y una regla, de acuerdo con sus indicaciones, se debe contar también con un cerro desde donde podamos divisar el horizonte desde un lugar despejado en dos direcciones opuestas. La altura ideal de esta colina o promontorio seria de 30 a 300 metros sobre el nivel del mar (fácilmente podría ser desde un edificio); desde ella se divisara claramente una zona despejada. La motivación principal es proporcionar un marco para que los estudiantes en clase diserten acerca de la posibilidad de medier el tamaño de la tierra con argumentos muy sencillos y al alcance de todos. Se estimula de formulación de proyectos para investigación en el aula. Además se considera, en concordancia con las reformas de la educación y la globalización de las ciencias y los conocimientos, como estas actividades pueden acoger distintas disciplinas para un análisis óptimo de los resultados.Palabras Clave: Proyectos de Aula; Física Interactiva; Diámetro de la Tierra.Measuring the diameter of the earthIn different ways have managed interesting procedures for measuring the radius of the earth. Here one is exposed to the use of many formal techniques or not for that aim. The procedure is simple enough so that any amateur can repeat. This is not a new method, but it can be seen as slight variations at the same might give less or more errors. The method requires three stones, a rope and a rule, in accordance with their instructions, it must also have a hill from where we can see the horizon from a site cleared in two opposite directions. The ideal height of this hill or serious promontory of 30 to 300 meters above sea level (easily could be from a building); since she divisara clearly an area cleared. The main motivation is to provide a framework for students in the classroom diserten about the possibility of medier size of the earth with arguments very simple and accessible to everyone. It stimulates project formulation for research in the classroom. Also under consideration, in line with the education reforms and the globalization of science and knowledge, as these activities can accommodate different disciplines for a discussion of optimal results.Keywords: Classroom projects; Interactive Physics; Earth's Diameter

In vivo characterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle through ultrasound-guided hybrid near-infrared spectroscopies

Objective. In this paper, we present a detailed in vivo characterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle (SCM), obtained through ultrasound-guided near-infrared time-domain and diffuse correlation spectroscopies. Approach. A total of sixty-five subjects (forty-nine females, sixteen males) among healthy volunteers and thyroid nodule patients have been recruited for the study. Their SCM hemodynamic (oxy-, deoxy- and total hemoglobin concentrations, blood flow, blood oxygen saturation and metabolic rate of oxygen extraction) and optical properties (wavelength dependent absorption and reduced scattering coefficients) have been measured by the use of a novel hybrid device combining in a single unit time-domain near-infrared spectroscopy, diffuse correlation spectroscopy and simultaneous ultrasound imaging. Main results. We provide detailed tables of the results related to SCM baseline (i.e. muscle at rest) properties, and reveal significant differences on the measured parameters due to variables such as side of the neck, sex, age, body mass index, depth and thickness of the muscle, allowing future clinical studies to take into account such dependencies. Significance. The non-invasive monitoring of the hemodynamics and metabolism of the sternocleidomastoid muscle during respiration became a topic of increased interest partially due to the increased use of mechanical ventilation during the COVID-19 pandemic. Near-infrared diffuse optical spectroscopies were proposed as potential practical monitors of increased recruitment of SCM during respiratory distress. They can provide clinically relevant information on the degree of the patient's respiratory effort that is needed to maintain an optimal minute ventilation, with potential clinical application ranging from evaluating chronic pulmonary diseases to more acute settings, such as acute respiratory failure, or to determine the readiness to wean from invasive mechanical ventilation.</p

Comparison of [18F] fluorocholine PET/CT with [99mTc] sestamibi and ultrasonography to detect parathyroid lesions in primary hyperparathyroidism: a prospective study.

Background: Primary hyperparathyroidism is a common endocrine disorder produced by the increase of parathyroid hormone (PTH) due to a benign adenoma of a single parathyroid gland, or as multiple gland hyperplasia, or as a rare malignant tumor. Preoperative imaging scans are frequently necessary for the minimally invasive parathyroidectomies to identify the location of enlarged parathyroid glands and to design the procedure. Methods: The diagnostic reliability of [18F]fluorocholine positron emission tomography/computed tomography (FCH PET/CT), [99mTc]sestamibi [multiplexed ion beam imaging (MIBI)] and cervical ultrasonography was analyzed in 37 patients diagnosed with primary hyperparathyroidism undergoing minimally invasive parathyroidectomy. The three preoperative imaging techniques were correlated with intraoperative and histopathological findings as well as changes in biochemical parameters (serum PTH and calcium levels). Statistical analysis was carried out with SPSS version 24.0. Results: In 30 of 37 patients (81.1%), FCH PET/CT correctly localized the pathological gland. In 3 cases of ectopic adenomas, the accuracy of the techniques was 100% (3/3) for FCH PET/CT, 66.7% (2/3) for MIBI, and 33.3% (1/3) for neck ultrasonography. Neither neck ultrasonography nor MIBI were able to locate pathological parathyroid glands in those patients with multiglandular disease, while FCH PET/CT correctly located one patient (1/3, 33.3%) with two adenomas and 3 patients (3/6, 50.0%) with hyperplasia. The three imaging techniques, FCH PET/CT, MIBI and neck ultrasound yielded a sensitivity of 92.1%, 57.9% and 32.4%, a positive predictive value of 94.6%, 84.6% and 78.6%, and a diagnostic accuracy of 96.4%, 85.7% and 79.0%, respectively. Conclusions: In this group of patients diagnosed with primary hyperparathyroidism, FCH PET/CT was superior to MIBI and neck ultrasound in detecting adenomas, particularly in the presence of ectopic glands or multiglandular disease

Predictive model of pheochromocytoma based on the imaging features of the adrenal tumours

The purpose of our study was to develop a predictive model to rule out pheochromocytoma among adrenal tumours, based on unenhanced computed tomography (CT) and/or magnetic resonance imaging (MRI) features. We performed a retrospective multicentre study of 1131 patients presenting with adrenal lesions including 163 subjects with histological confirmation of pheochromocytoma (PHEO), and 968 patients showing no clinical suspicion of pheochromocytoma in whom plasma and/or urinary metanephrines and/or catecholamines were within reference ranges (non-PHEO). We found that tumour size was significantly larger in PHEO than non-PHEO lesions (44.3 +/- 33.2 versus 20.6 +/- 9.2 mm respectively; P < 0.001). Mean unenhanced CT attenuation was higher in PHEO (52.4 +/- 43.1 versus 4.7 +/- 17.9HU; P < 0.001). High lipid content in CT was more frequent among non-PHEO (83.6% versus 3.8% respectively; P < 0.001); and this feature alone had 83.6% sensitivity and 96.2% specificity to rule out pheochromocytoma with an area under the receiver operating characteristics curve (AUC-ROC) of 0.899. The combination of high lipid content and tumour size improved the diagnostic accuracy (AUC-ROC 0.961, sensitivity 88.1% and specificity 92.3%). The probability of having a pheochromocytoma was 0.1% for adrenal lesions smaller than 20 mm showing high lipid content in CT. Ninety percent of non-PHEO presented loss of signal in the out of phase MRI sequence compared to 39.0% of PHEO (P < 0.001), but the specificity of this feature for the diagnosis of non-PHEO lesions low. In conclusion, our study suggests that sparing biochemical screening for pheochromocytoma might be reasonable in patients with adrenal lesions smaller than 20 mm showing high lipid content in the CT scan, if there are no typical signs and symptoms of pheochromocytoma

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction