Features of the distribution of events by the multiple of secondary particles depending on the energy of collision and the assymetricity of collising relativistic nuclei

To search for signals of the phase transition of matter from the hadronic state to the quark­gluon plasma, interactions with extreme characteristics are studied. The study of the dependence of the av­erage multiplicity on the projectile energy for sulfur and silicon nuclei with energies of 3.7 AGeV, 14 AGeV, and 200 AGeV has been carried out. Experimental data on inelastic interactions with the nuclei of the NIKFI BR­2 emulsion obtained at the SPS at CERN and at the Synchrophasotron at JINR. To take into account fluctuations in the initial conditions of the nucleus­nucleus interaction, the events were divided into central and peripheral ones. A comparative analysis of the average multiplicity with heavy and light nuclei of the photographic emulsion is presented. The multiplicity increase factor has an almost linear increase in energy (on the logarithmic axis) for all events, except for the central interactions of sulfur nuclei with heavy emulsion nuclei at 200 AGeV. These events are explosive events, which give a flux of secondary particles in a narrow range of average pseudo­rapidity and significantly shifted towards low values <η>. The analysis of events of complete destruction of the projectile nucleus is presented. Such events are considered as events in which the most favorable conditions are created for the formation of a quark­gluon plasma.

OPERA tau neutrino charged current interactions

The OPERA experiment was designed to discover the vτ appearance in a vμ beam, due to neutrino oscillations. The detector, located in the underground Gran Sasso Laboratory, consisted of a nuclear photographic emulsion/lead target with a mass of about 1.25 kt, complemented by electronic detectors. It was exposed from 2008 to 2012 to the CNGS beam: an almost pure vμ beam with a baseline of 730 km, collecting a total of 1.8·1020 protons on target. The OPERA Collaboration eventually assessed the discovery of vμ→vτ oscillations with a statistical significance of 6.1 σ by observing ten vτ CC interaction candidates. These events have been published on the Open Data Portal at CERN. This paper provides a detailed description of the vτ data sample to make it usable by the whole community.

Phytograms: Rebuilding Human–Plant Affiliations

This article proposes the phytogram, an image made by using the internal chemistry of plants in conjunction with photographic emulsion. First, a theoretical framework is set out, drawing inspiration from structural/materialist film theory, biosemiotics and perspectivism. The notion of plant sensations/perceptions is questioned, developing the real possibility of human–plant communication. Subsequently, a summary of the materials and methods involved in making phytograms is included in order to show how an inter-dependency of technological and natural elements can lead to evocative results and spontaneous animation. Instead of bringing inert matter to life, the image moves by itself. This practice can bring people together, sharing knowledge about their environment while enjoying the cohesion of a wider community and history of people and plants. Making such an extended community visible is significant with regard to a heightened awareness of the natural environment. Instead of preaching ecological propriety and austere behaviour, phytography offers a positive and fulfilling engagement with our living environment.

Fabrication of Deterministic Micro-Asperities on Thrust Surfaces Using Photo Chemical Machining

The present invention relates to characterization and the sequence of operations in photo chemical machining as a means to fabricate positive deterministic micro-textures on mild steel thrust pad surfaces. Fabrication of surface micro-texture by current technique is conceived in two-stages: where photographic emulsion process is used to pattern the microstructure, and chemical etching method is employed to fabricate the textures on mild steel surface by dissolving exposed metal surface. The texture fabricated by present invention is having slightly rough etched bottom surface with sharp edge and least amount of burrs around the texture rim and the process is also cost effective. Several aspects regarding sequence of operations in manufacturing process and the characterization of fabricated textured surfaces are discussed. The physical significance of micro-asperities on hydrodynamic lubrication is presented experimentally under constant flow system. The variation of hydrodynamic performance parameters such as frictional torque, fluid film thickness and recess pressure with different operating conditions such as varying speed and supply pressure are outlined.

Solar observations at the Coimbra Astronomical Observatory

In 2020, the Geophysical and Astronomical Observatory of the University of Coimbra will celebrate the 95th anniversary of its first spectroheliographic observation. Keeping a daily service of solar observations since then, making almost a century, led to one of the largest continuous solar data collections in the world. This long–term solar database is essential for studies where solar activity is involved. This work reviews the development of synoptic observations made at the Observatory of Coimbra since 1925 and presents a summary of some of the principal stages of the Observatory’s history since its founding in 1772. We refer the main technical improvements and present some perspectives for the near future. One of the most significant upgrades was the installation of a CCD camera in 2007. The transition from photographic emulsion to digital recording methods allowed the development of image analysis algorithms to process solar images and improved data sharing with other institutions. This upgrade enabled also to carry–out modern climate and space weather studies. This valuable advancement makes it possible to create a new catalogue of solar observations to be published in the future.

Gelatin as a Photosensitive Material

Because this issue journal is dedicated to Gelatin, here we present a few applications of gelatin in the field of optics. Optics is the science that studies the production, propagation, interaction and detection of light. Various materials sensitive to light (photosensitive) are used for detection of light, such as photomultipliers, CCDs, crystals, two dimensional (2D) materials and more. Among the 2D materials, the most popular for several centuries has been gelatin based photographic emulsion, which records spatial distributions of light. More recently (1970), films made of Gelatin with Dichromate (DCG) and dyes have been used. We describe some characteristics and applications of these two photosensitive materials. We also describe examples where gelatin is used as a Relative Humidity (RH) sensor and in the fabrication of optical elements based on gelatin. This article is intended for researchers outside the optics community.

Gelatin as Photosensitive Material

Because this issue journal is dedicated to Gelatin here we present a few applications of gelatin in the field of optics. It is understood that optics is the science that studies the production, propagation, interaction and detection of light. Regarding the detection there are some materials sensitive to light (photosensitive) that are used like photomultipliers, CCD&rsquo;s, crystals, two dimension (2D) materials and more. Among the 2D materials the most popular through several centuries has been gelatin based photographic emulsion that records spatial distributions of light. More recently (1970) films made of Gelatin with Dichromate (DCG) and dyes have been used. We describe some characteristics and applications of these two photosensitive materials. Also we describe examples where gelatin is used as Relative Humidity (RH) sensor and in the fabrication of optical elements based on gelatin. This article is intended to researchers outside the optics community.

Azimuthal structure of charged particle emission in 28Si–Ag/Br interaction at 14.5A GeV and 32S–Ag/Br interaction at 200A GeV

Presence of unusual azimuthal structures in the particle emission data obtained from the 28 Si – Ag / Br interaction at 14.5A GeV and from the 32 S – Ag / Br interaction at 200A GeV, are investigated in the framework of the Cherenkov gluon emission and/or Mach shock wave formation in nuclear/partonic medium. Nuclear photographic emulsion technique is used to collect the experimental data. The experiment is compared with the predictions of two simulations, namely (i) the Relativistic Quantum Molecular Dynamics (RQMD) and (ii) the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). A charge reassignment algorithm is implemented over the outputs of the simulations to mimic the Bose–Einstein correlation (BEC) effect. Our analysis confirms presence of jet-like structures in both experiments beyond statistical noise. Such structures are more pronounced in the 32 S data than in the 28 Si data.