Constrained deformation of an Al based amorphous alloy by cold rolling

In this work, we report on the mechanisms of deformation and fracture of an Al₈₇Ni₇La₆ amorphous alloys by cold rolling. Ribbons were cold rolled at room temperature embedded in pure Al-foils (volume fraction 20%). Scanning Electron Microscopy observations of the cross section of the deformed samples revealed that, after a few rolling passes, ribbons broke into fragments and formed shear bands because of the load exerted by the ductile Al matrix starting from the roughness on the surfaces. The shear band offset was higher near the fracture surface, suggesting that a stress concentration occurs when the slip of shear band is hindered by the presence of constraint. In ribbons rolled alone elongation above 3% was achieved as well as flattening of the surface roughness.Fracture surfaces of ribbon fragments presented mainly features due to brittle shear and a limited number of veins and filaments suggesting mixed mode of fracture.No formation of crystals in the shear bands was evidenced by Transmission Electron Microscopy and Differential Scanning Calorimetry.     

Experimental assessment of color-rendering indices and color appearance under varying setups

The Color-Rendering Index (CRI) for light source is a quantitative measure of the capability to preserve color appearance of illuminated objects. Recently, CRI has had a renewed interest because of the new LED-based lighting systems. These sources usually have a Color-Rendering Index rather low, but a good preservation of color appearance and a pleasant visual appeal. Various attempts to develop a more reliable new color-rendering index have been done so far, but researchers are still working on the topic. This article presents the open issues related to CRI and discusses some of the approaches available in literature. In order to have a baseline to verify the above points, we present an experiment performed with human observers to assess the appearance preservation of a color under a set of light sources. The test protocol uses 3D reference objects and can be used as an alternative way to assess CRI. The results are then compared with a range of available color rendering indices. The goal is not to make a rank among CRIs, rather to assess their variability relative to human judgment through different setups and light sources.     

Cascading Wafer-Scale Integrated Graphene Complementary Inverters under Ambient Conditions

The fundamental building blocks of digital electronics are logic gates which must be capable of cascading such that more complex logic functions can be realized. Here we demonstrate integrated graphene complementary inverters which operate with the same input and output voltage logic levels, thus allowing cascading. We obtain signal matching under ambient conditions with inverters fabricated from wafer-scale graphene grown by chemical vapor deposition (CVD). Monolayer graphene was incorporated in self-aligned field-effect transistors in which the top gate overlaps with the source and drain contacts. This results in full-channel gating and leads to the highest low-frequency voltage gain reported so far in top-gated CVD graphene devices operating in air ambient, A(v) ～ -5. Such gain enabled logic inverters with the same voltage swing of 0.56 V at their input and output. Graphene inverters could find their way in realistic applications where high-speed operation is desired but power dissipation is not a concern, similar to emitter-coupled logic.     

Epigenetics and Helicobacter pylori

Epigenetics regulates gene expression, cell type development during differentiation, and the cell response to environmental stimuli. To survive, bacteria need to evade the host immune response. Bacteria, including Helicobacter pylori (Hp), reach this target epigenetically, altering the chromatin of the host cells, in addition to several more approaches, such as DNA mutation and recombination. This review shows that Hp prevalently silences the genes of the human gastric mucosa by DNA methylation. Epigenetics includes different mechanisms. However, DNA methylation persists after DNA replication and therefore is frequently associated with the inheritance of repressed genes. Chromatin modification can be transmitted to daughter cells leading to heritable changes in gene expression. Aberrant epigenetic alteration of the gastric mucosa DNA remains the principal cause of gastric cancer. Numerous methylated genes have been found in cancer as well as in precancerous lesions of Hp-infected patients. These methylated genes inactivate tumor-suppressor genes. It is time for us to complain about our genetic and epigenetic makeups for our diseases.     

Munsell and Ostwald colour spaces: A comparison in the field of hair colouring

Colour science has had a very long history, dotted over the millennia with many contributions from the most diverse fields of human knowledge. At the beginning of the 20th century, Albert Henry Munsell, an artist formally trained in academia, and Friedrich Wilhelm Ostwald, Nobel prize for chemistry in 1909 and amateur painter, each envisioned and developed a colour system with a related colour atlas. Both authors recognized the importance of the visual relationship between colours, which they conceived as sensations stemming from, but not merely confined to, pigments and light. We hereby describe the salient features of these colour spaces, their strengths and weaknesses, the authors' analogy of intents and divergence in execution. The contribution of this paper is a discussion on how these are employed both in Italian educational facilities, and salon practice, as well as a suggestion about their use within the industry of human hair cosmetics.     

T-stress solution for DCDC specimens

A finite element study is performed in order to determine the T-stress term for DCDC specimens with holes set off from the specimen centre line. In addition, mixed-mode stress intensity factors K_I and K_II are given and the biaxiality ratio β is computed from T and K_I. The T-stress results are fitted and presented in a simple relation.     

T-stress of cracks loaded by near-tip tractions

T-stress solutions were derived for tractions acting on the crack-faces near a crack tip. Such solutions are of interest for the determination of the leading term of a weight function representation of T-stresses and the computation of an “intrinsic” T-stress for cracks growing in a material with a rising crack growth resistance. First, the type of the Green’s function for T-stresses is theoretically established. Then, results of finite element computations are reported for edge-cracked bars, DCB and CT specimens, which are suited for the determination of the first series term. As an application of the Green’s functions, the T-stresses caused by bridging interactions very close to the crack tip are computed.     

An in-service measurement system for the quality analysis offacsimile transmissions

The paper presents a measurement technique for the assessment of the degree of quality of facsimile transmissions over a telephone-type network that can be performed while the communication lines are in use. The main impairments introduced by the telecommunication channel are continuously measured by using a blind equalization technique and a timing recovery system, thus assuring a high accuracy with a reasonable measurement time, even under poor signal-to-noise ratio (SNR) conditions. Experimental results, that confirm the good performance of the proposed method, are reported and discussed