Vlada pastushenko progress on fluorine-free electropolishing
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High purity niobium (Nb) is used to make superconducting radio frequency (SRF) cavities. To improve the cavity performance it is necessary to reduce the surface resistance as much as possible. To achieve this goal each Nb cavity undergoes to a series of successive treatments (mechanical polishing, buffered chemical polishing, electropolishing, annealing). Choline Chloride-based ionic liquids are considered as a new class of electrolytes. Comparing to traditional ionic liquids, choline chloride-based ionic liquids are low toxic, biodegradable, and the price is generally low, which make them more and more attractive in green chemistry and industrial chemistry. Since it was found that, the mixture of Choline Chloride and Urea can polish Niobium every year, this solution has been improved. Was investigated the optimal ratio of Choline Chloride and Urea, studied the effect of additives, temperature and current density. When it was found suitable parameters for the polishing of planar samples, we have started to implement it to the polishing of 6 GHz Niobium cavities.
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This document provides details on methods for analyzing chemical oxygen demand (COD) using standards from the American Public Health Association (APHA) manual. It describes three common COD analysis methods: the open reflux method, closed reflux titrimetric method, and closed reflux colorimetric method. For each method, it outlines the key steps, including refluxing samples with dichromate and sulfuric acid, and then titrating or measuring color change to determine the amount of dichromate consumed and calculate the COD level. The document also discusses interferences, limitations, sampling, and analysis of COD values both above and below 50 mg O2/L.
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Biological Nutrient Removal Applications for Monitoring ORP | YSI
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Biochemical oxygen demand (BOD) AND Chemical Oxygen Demand PDF
Application Note: Determination of Impurities in Silica Wafers with the NexIO...
Application Note: Determination of Impurities in Silica Wafers with the NexIO...
Alkali P-Nitrophenolates for Short Wavelength Laser Generation
Alkali P-Nitrophenolates for Short Wavelength Laser Generation
Enzo palmieri experimental results on thermal boundary resistance for niobi...
Enzo palmieri experimental results on thermal boundary resistance for niobi...
Precipitation of indium using sodium tripolyphosphate
Precipitation of indium using sodium tripolyphosphate
chemical oxygen demand -analysis using APHA manual
chemical oxygen demand -analysis using APHA manual
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This document provides an outline of Chapter 21 from a biology textbook. It discusses plant organization and homeostasis. It begins by describing the basic shoot and root systems of flowering plants, including stems, leaves, branches, and roots. It then explains how plants are categorized as monocots or eudicots based on structural differences. The document outlines the three main tissue types found in plants - epidermal, ground, and vascular tissue - and how they are arranged and function in leaves, stems, and roots. It concludes by describing primary growth and how it causes lengthening of the root and shoot systems through cell division in the meristems located at the tips.
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Similar to Vlada pastushenko progress on fluorine-free electropolishing
10.1007_s10008-015-2847-2
The document describes the development of a silver nanoparticle-modified poly ortho-toluidine/carbon paste electrode (n-Ag/POT/MCPE) and its application as an anode for the electrocatalytic oxidation of hydrazine in alkaline media. Scanning electron microscopy images show that the n-Ag/POT/MCPE has a porous surface topology suitable for catalyzing hydrazine oxidation. Cyclic voltammetry experiments demonstrate that the electrode exhibits high anodic and cathodic currents, indicating a large surface area, and is electrochemically active for hydrazine oxidation, with the oxidation current increasing with hydrazine concentration.
David singapore
This document summarizes analytical chemistry techniques for determining the nature and quantity of substances in environmental samples. It discusses methods such as hydride generation atomic absorption spectrometry for elements like arsenic, inductively coupled plasma atomic emission spectrometry for its ability to analyze over 70 elements simultaneously, and anodic stripping voltammetry for its high sensitivity in detecting various heavy metals in parts-per-billion concentrations from water samples. The document also outlines techniques for speciating different forms of elements like arsenic and lead based on their behavior under various analytical conditions.
nitrate
This document summarizes research on the catalytic hydrogenation of aqueous nitrate over iron/carbon (Fe/C) catalysts. Key points:
- Batch and continuous reactor experiments show that Fe/C catalysts can effectively reduce nitrate in water to nitrogen gas with high selectivity and activity. Up to 2.9 mmol/gmetal/min nitrate reduction rate was achieved in batch tests.
- Column studies demonstrate the catalyst can reduce nitrate levels below 5 ppm from an initial 100 ppm concentration, with a breakthrough capacity of over 530 bed volumes to reach 45 mg/L.
- Characterization with XRD, SEM-EDAX and XPS confirms the presence of iron dispersed on the
Electrochemical Characterization of Electrocatalysts .pptx
This document summarizes an electrochemistry workshop presentation on electrocatalyst characterization. It introduces common electrochemical characterization methods like cyclic voltammetry and discusses key figures of merit for evaluating electrocatalyst activity. Examples are provided of electrocatalyst development for important reactions like hydrogen evolution, oxygen evolution, and oxygen reduction. These include developing non-precious metal catalysts and improving catalyst stability and performance through methods like decreasing platinum loading or synthesizing metal phosphides and metal oxides on supports.
A0450102
Anodic acetoxylation of anisole was carried out on graphite and platinum electrodes. On the graphite electrode, p-acetoxy anisole was the major product along with traces of hydroxy anisole. Using the platinum electrode, the major product was dimer along with traces of hydroxy anisole. The proposed mechanism involves the formation of a radical cation, which on the graphite electrode becomes chemisorbed and undergoes nucleophilic attack by acetate to form p-acetoxy anisole. On the platinum electrode, the radical cation diffuses into solution and dimerizes before potential nucleophilic attack by acetate to form dimer.
Research efforts direct ethanol fuel cell defc
The document summarizes research on developing palladium-tin alloy catalysts for ethanol oxidation in alkaline fuel cells. Key findings include:
1) Pd-Sn/C catalysts synthesized using a polyol method showed twice the peak current densities of Pd/C catalysts for ethanol oxidation.
2) The Sn content was found to enhance the charge transfer rate during ethanol oxidation reactions.
3) Ethanol was found to partially oxidize on the Pd-Sn catalysts, forming acetic acid. Future work will focus on facilitating complete ethanol oxidation through DFT calculations and improving synthesis methods.
Nitrate ACS 2016
The document summarizes an investigation into using transition metal ions like copper (II) to remove chloride interference from nitrate ion selective electrodes. Nitrate measurements were made using ion selective electrodes in flow injection analysis. The addition of copper (II) ions was found to complex with chloride ions, reducing chloride interference and allowing detection of nitrate down to 5 ppm. Selectivity coefficients improved from around 0.01 without copper (II) to around 0.001 when copper (II) was added, representing a tenfold reduction in chloride interference. Further optimization of copper (II) concentrations could provide an inexpensive way to measure nitrate in chloride-containing waters like seawater.
Nitrate ACS 2016
The document summarizes an investigation into using transition metal ions like copper (II) to remove chloride interference from nitrate ion selective electrodes. Nitrate measurements were made using ion selective electrodes in flow injection analysis. The addition of copper (II) ions was found to complex with chloride ions, reducing chloride interference and allowing detection of nitrate down to 5 ppm. Selectivity coefficients improved from around 0.01 without copper (II) to around 0.001 when copper (II) was added, representing a tenfold reduction in chloride interference. Further optimization of copper (II) concentrations could provide an inexpensive way to measure nitrate in chloride-containing waters like seawater.
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Chirkov - literature review of Nb electroplating
http://www.surfacetreatments.it/thinfilms
Literature Review of Nb Electroplating (Dmytro Chirkov - 20')
Speaker: Dmytro Chirkov - Legnaro National Laboratories of INFN | Duration: 20 min.
Abstract
The main aim of this work is try to understand if expensive techniques of niobium coating could be replaced by cheaper electroplating method.
Nowadays electrochemical surface treatment is one of the most used approaches in industry.
Aqueous solutions has been the most widely used process mainly because of advantages such us low cost, non-flammability, high solubility of electrolytes, high conductivities resulting in low ohmic losses, high solubility of metal salts and high rates of mass transfer. However, despite these advantages there are several limitations in using aqueous solutions such as limited potential windows, gas evolution processes that can result in hydrogen embrittlement, passivation of substrates, electrodes and deposits, and the necessity for hazardous complex agents such as cyanide, causing environmental contamination. These are the reasons why new non-aqueous solutions to electrodeposit niobium have been researched.
One of the main limitations in using aqueous solutions is their narrow electrochemical window. The major reason for carrying out electrodeposition in non-aqueous electrolytes (such as conventional organic solvents, ionic liquids and molten salts) is water and air stability and the wide electrochemical window of these media.
Alternatively, also high temperature molten salts have been used extensively for niobium electrodeposition. They have wide potential windows, high conductivities and high solubility for metal salts. In fact, they have most of the advantages of aqueous solutions and overcome most of the limitations of aqueous solutions, but their one major limitation is the very high temperature (more than 750 °C).
Therefore, the alternative to high temperature molten salts was an ionic substance that melts at a low temperature. Over the last few decades, room temperature ionic liquids have been widely studied in various scientific fields due to their interesting properties, such as negligible vapour pressures, high chemical and thermal stability, acceptable intrinsic ionic conductivity and wide potential window.
Ionic liquids are molten salts with melting points below 100 °C and they consist entirely of cations and anions. The development of ionic liquids, especially air and water stable types, has attracted extensive attention since they have outstanding physical properties.
The aim of this work will be the analysis of available literature data in order to have precise knowledge about niobium behavior in the different electrolytes and to get new information about possible electrolytes based on ionic liquids.
Undergraduate Laboratory Development: Finding Cost-Effective Catalysts for th...
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Conductometry- Pharmaceutical Analysis
Introduction
Ohm’s law.
Conductometric measurements.
Factor affecting conductivity.
Application of conductometry.
2.Conductometric titration-:
Introduction.
Types of conductometric tiration.
Advantages of conductometric tiration.
3.Recent devlopement
Conductometry:
is the simplest of the electroanalytical techniques; by Kolthoff in 1929.
Conductors are:
either metallic (flow of electrons) or electrolytic (movemenmt of ions).
Conductance of electricity:
migration of positively charged ions towards the cathode and negatively charged ones towards the anode
(i.e.) current is carried by all ions present in solution.
Conductance depends on the number of ions in solun.
Factors affecting conductance:
1- Temperature:
(1C increase in temperature causes 2 % increase in conductance).
2- Nature of ions
Size, molecular weight and number of charges.
3- Concentration of ions:
As the number of ions increases, the conductance increases.
4- Size of electrodes
Conductance is directly proportional to the cross sectional area (A).
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Acid–base reactions on alumina supported niobia
The document describes a study of acid-base reactions on alumina-supported niobia catalysts. Catalysts containing 8-28% niobia supported on gamma-alumina were prepared by impregnation. The catalysts were characterized using infrared spectroscopy, CO2 adsorption, and UV-vis spectroscopy. The density and strength of Lewis acid and basic sites decreased with increasing niobia content, while the density of Brønsted acid sites increased. The catalysts were tested in isopropanol dehydration, 1-butene isomerization, and cumene dealkylation reactions. Reaction performance varied with different reactions responding differently to niobia addition depending on the changes in surface acid-base properties.
DIFFERENT pH MEASUREMENT TECHNIQUE.pdf
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S. Y. B.Sc.
This document outlines the syllabus for Semesters III and IV of an S.Y.B.Sc. in Chemistry. Semester III covers Physical and Inorganic Chemistry, including topics like thermodynamics, chemical equilibrium, phase equilibrium, and the chemistry of transition metals. Semester IV covers similar topics, along with electrochemistry, solid state, and colloidal chemistry. Both semesters include organic chemistry courses covering topics such as spectroscopy, alcohols, ethers, aldehydes and ketones. The document also lists textbooks, reference books, and laboratory experiments for each semester.
Chemistry investigatory project
The document is an investigatory project report submitted by Arpan Gupta to his chemistry teacher on the electrolysis of potassium iodide. It includes an introduction thanking those involved, the aim and apparatus used, background theory on electrolysis including Faraday's laws, the reactions and products expected, the procedure followed, observations made, and precautions and references.
Paper
This document summarizes research on using antimony-impregnated activated carbon as an electrode for detecting heavy metal ions like cadmium and lead using anodic stripping voltammetry. The researchers impregnated activated carbon with different amounts of antimony and found that electrodes with 5% antimony by weight produced the highest peak currents - 29.2 microamps for cadmium and 49.4 microamps for lead in a 100 microgram per liter solution, outperforming previous methods. The results indicate antimony-impregnated activated carbon is an effective working electrode for detecting heavy metals at low concentrations.
Performance of carbon nanofiber supported pd–ni catalysts for electro oxidati...
Carbon nanofibers (CNF) supported Pd–Ni nanoparticles have been prepared by chemical reduction
with NaBH4 as a reducing agent. The Pd–Ni/CNF catalysts were characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical
voltammetry analysis. TEM showed that the Pd–Ni particles were quite uniformly distributed on the
surface of the carbon nanofiber with an average particle size of 4.0 nm. The electro-catalytic activity of
the Pd–Ni/CNF for oxidation of ethanol was examined by cyclic voltammetry (CV). The onset potential
was 200mV lower and the peak current density four times higher for ethanol oxidation for Pd–Ni/CNF
compared to that for Pd/C. The effect of an increase in temperature from 20 to 60 ◦C had a great effect on
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More from thinfilmsworkshop
V. Palmieri - Superconducting resonant cavities
There is no dubt that the subject of superconducting resonant cavities is a fascinating field both physical and engineering point of view.
The application of superconductivity to the world of resonant cavities has made achievable results unimaginable otherwise.
Independently of the special field of application, superconducting resonant circuits have superior performances compared to roo-temperatire circuits.
However the greatest resource of such devices stays not in the high quality of the results already obtained, but in all potential applications and new ideas that must be still developed.
V. Palmieri - The classical superconductivity
When hearing about persistent currents recirculating for several year in a superconducting loop without any appreciable decay, we realize that we are dealing with a phenomenon wich in nature is the closest we know to the perpetual motion.
The zero resistivity and the perfect diamagnetism in Mercury at 4.2 K, the discovery of superconducting materials, finally the revolution of the "liquid Nitrogen superconductivity": Nature discloses drop by drop its intimate secrets.
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The document discusses plans to form an international collaboration to study future circular colliders at CERN, including a 100 TeV proton-proton collider (FCC-hh), a lepton collider (FCC-ee), and a lepton-hadron collider (FCC-he). It outlines initial parameters and opportunities for the superconducting radio frequency (RF) systems, which will need to provide up to 100 MW of continuous wave power to accelerate beams. Key areas of study for the large-scale FCC RF systems include cavity and cryomodule technology, reliability, efficiency, and operational aspects.
Tesi Master Andrea Camacho Romero
This works deals with the A15 compound synthesis on niobium samples and over the
internal surface of niobium cavities by means of induction heating. Specifically, three compounds were studied: Nb3Ga, Nb3Al and Nb-Al-Ga. As for the preparation of the niobium samples, they were treated with BCP solution in order to polish the surface. The niobium cavities were treated with centrifugal tumbling, BCP solution and high pressure water rising. Subsequent, the samples, or cavities, were placed into an inductor controlling the voltage, time, sample position, temperature, type and pressure of gas used. The highest critical temperature
obtained was 18 K and Tc 0,35 K, in Nb-Al-Ga#1 sample by inductive measurement.
Mapping analysis showed the uniform diffusion of aluminum into the niobium, and the gallium diffuses creating channels into niobium. The composition was measured by EDS obtaining (82±1)% wt. Niobium, (11,3±0,9)% wt. Gallium, (4,7±0,2)% wt. Aluminum and (1,9±0,1)% wt. Oxygen. Finally, RF test confirmed that the cavities obtained after the annealing were normal conductive indicating that the preparation parameters must still be optimized.
Tesi Bachelor Debastiani
In questi ultimi anni i problemi energetici e ambientali hanno favorito lo sviluppo di un nuovo settore della ricerca riguardo la produzione di energia pulita sfruttando fenomeni naturali. L'attenzione dei ricercatori è stata catturata dalla possibilità di convertire l'energia solare luminosa
in energia elettrica. Questo processo di conversione, nato nella prima metà del XX secolo, permette di produrre correnti elettriche anche in piccola scala, senza la realizzazione di imponenti impianti industriali e soprattutto senza la produzione si scorie inquinanti. Sono nate così le prime celle solari
a effetto fotovoltaico.
Gli sviluppi hanno portato a diversi risultati e al giorno d'oggi l'energia fotovoltaica ha ormai fatto il suo ingresso nella vita quotidiana. Sia i favori delle industrie, sia l'interesse dei privati cittadini, contribuiscono a espandere questo tipo di ricerca, ottenendo numerosi successi nell'aumento
dell'efficienza di conversione energetica. Dal punto di vista della scienza dei materiali la prima cosa che viene in mente pensando alle celle
fotovoltaiche è il silicio. A tutti gli effetti la maggior parte delle celle sul commercio sono costituite da silicio policristallino, per le sue ottime qualità e proprietà di resa. Tuttavia esistono anche una moltitudine di altri composti, alcuni più recenti di altri, che sono ancora nell'occhio dei ricercatori, un esempio ne sono i recenti foto-materiali organici. Spesso però i costi di realizzazione sono alti per ottenere rese elevate, rendendo così proibitive le realizzazioni su impianti industriali. L'ossido rameoso (Cu2O) è stato uno dei capostipiti dei materiali utilizzati nelle celle fotovoltaiche.
Fin dal suo primo utilizzo nel 1958 esso ha presentato le caratteristiche di semiconduttore necessarie alla realizzazione di impianti fotovoltaici. Rispetto ai sui cugini più nobili, presenta delle efficienze minori, ma anche un costo decisamente più basso. Il rame infatti, da innumerevoli anni, è un elemento largamente sfruttato in tutti i campi dell'elettronica e non solo, e la realizzazione di ossidi specifici non comporta processi troppo complessi o costosi.
La ricerca nel campo dell'ossido rameoso è riuscita a migliorare le sue qualità all'interno del mondo fotovoltaico rendendo possibile la realizzazione di celle solari a costi contenuti.
Per questo motivo il Cu2O è tutt'oggi un materiale in grado di competere nel moderno panorama della ricerca solare fotovoltaica.
Tesi Bachelor Giovanni Vergari
Il plasma è un supporto particolarmente attivo dal punto di vista chimico e fisico. In base al modo con cui viene attivato e alla potenza di lavoro, può generare temperature basse o molto elevate e viene definito rispettivamente come plasma freddo o caldo. Quest’ampio range di temperature lo rende adatto a numerose applicazioni tecnologiche: rivestimento di superficie, smaltimento rifiuti, trattamento dei gas, sintesi chimiche, lavorazioni industriali. La maggior parte di queste applicazioni del plasma non sono ancora state industrializzate, sebbene il loro sfruttamento rispetti strettamente le norme sull’inquinamento.
I plasmi caldi (specialmente quelli ad arco) sono ampiamente industrializzati, con particolare diffusione all’interno del settore aereonautico. La tecnologia dei plasmi freddi è stata sviluppata in microelettronica, ma le apparecchiature da vuoto richieste ne limitano l’applicabilità.
Al fine di evitare l’inconveniente associato al vuoto, molti laboratori hanno provato a trasferire a pressione atmosferica processi che attualmente lavorano in vuoto. Le ricerche condotte hanno portato alla scoperta di varie ed innovative sorgenti che verranno descritte in questo elaborato.
Dopo un riassunto sui differenti tipi di plasmi, saranno descritte le varie sorgenti in termini di design, condizioni di lavoro e proprietà del plasma. In seguito l’attenzione sarà spostata sulle varie applicazioni (analisi spettroscopica, trattamento dei gas e processi sui materiali).
Tesi master Ram Khrishna Thakur
The lowest possible surface resistivity and higher accelerating field are the paramount
considerations, hence are obligatory for accelerating cavities. Since, superconducting materials
are used to make radio-frequency cavities for future accelerators. In the case of rf cavities,
superconductors are being used in order to minimize the power dissipated and increase the
figures of merit of a radio-frequency cavity, such as the quality factor and accelerating gradient.
Hence, these could be achieved by improving surface treatment to the cavity, and processing
techniques must be analyzed in order to optimize these figures of merit.
The research work reported in this dissertation mainly carried out on tesla type seamless 6GHz
Nb and Cu cavities. We have developed two innovative techniques: firstly, for mechanical
polishing of cavities, and secondly for purification of these cavities at atmospheric pressure under
cover of 4Helium gas (for protection) and at ultra-high vacuum (UHV) system. These cavities are
fabricated by spinning technology to create seamless cavities.
The main advantages of 6 GHz bulk-Nb cavities are saving cost, materials and time to collect
statistics of surface treatments and RF test in a very short time scale. Cavities are RF tested
before and after high temperature treatment under atmospheric pressure (under cover of inert gas
atmosphere to protect inner and outer surface of cavity) inside transparent quartz tube, and under
UHV conditions. Induction heating method is used to anneal the cavity at temperatures higher
than 2000°C and close to the melting point of Nb for less than a minute while few seconds at
maximum temperature. Before RF test and UHV annealing, the surface treatment processes like
tumbling, chemical, electro-chemical (such as BCP and EP), ultrasonic cleaning and high
pressure rinsing (HPR) have been employed. High temperature treatment for few minutes at
atmospheric pressure allow to reduce hydrogen, oxygen and other elemental impurities, which
effects on cavity Q-factor degradation, hence recovers rf performances of these cavities. This
research work will address these problems and illustrate the importance of surface treatments.
Tesi master Goulong yu
6 GHz spun seamless Superconducting Radio Frequency (SRF) cavities are a very
useful tool for testing alternative surface treatments in the fabrication of TESLA cavity.
However, the spinning technique has also some drawbacks like contamination, surface
damage in internal part due to the collapsible mandrel line. The first important step of
the surface treatments is the mechanical polishing. For this purpose, a new, cheap, easy
and highly efficient tumbling approach based on vibration was developed.
Before this approach was conceived, a few other methods, such as Turbula,
Centrifugal Barrel Polishing (CBP), custom Zigzag tumbler and “flower brush” have
been studied and tested. But the result was not so satisfactory neither for the low erosion
rate nor for the unstableness of the system nor for the complicated polishing process. At
last, a vibration system with a simple structure, working stably was created after two
experiments.
Another important task of the thesis is to update the optical inspection system for 6
GHz cavities. 3 stepper motors motor was added to move and rotate the cavity and
realized auto focus of the miniature camera. A software was developed to achieve a full
cavity photographed by one key operation using LabVIEW.
A high-efficiency mechanical polishing system is generally judged by two aspects:
one is whether the surface property satisfies the demand after polishing; the other is
whether the erosion rate can reach and be stabilized at a high value which is comparable
or greater than the existing products. The Radio Frequency (RF) test result indicates that
the vibration system is feasible. The latest erosion rate 1 gram/hour i.e. removing 13
microns depth of inner surface materials per hour exceeds the performance of CBP,
which is widely used in other laboratories in the world.
The mechanical polishing process is elaborated and cavities that have been polished
are listed. Several influencing factors on the erosion rate, such as tumbling time, media,
signal and multi-cavities and plate direction are discussed at the end.
A preliminary design of 1.3 GHz vibration system as the future development is
provided for the next plan.
Tesi magistrale Akaberi Nazkhatoon
In questo lavoro di tesi verrà presentato un primo prototipo di un mini inceneritore al plasma per la pirolisi dei rifiuti medicali basato sulla tecnologia delle torce al plasma a microonde (MW) con tecnologia domestica a basso costo.
Si inizia con una breve e generale descrizione sulle problematiche dei rifiuti, della loro classificazione e delle norme che ne regolano lo smaltimento. Quindi si parlerà delle norme necessarie per l‟identificazione dei rifiuti medicali ed infine verrà riassunta la modalità di gestione dei rifiuti secondo la normativa in vigore.
Successivamente saranno descritti alcuni metodi di termodistruzione dei rifiuti ospedalieri come la combustione negli inceneritori tradizionali, e alcuni metodi alternativi, come il trattamento al plasma atmosferico, andando ad analizzare vantaggi e svantaggi di ogni tecnologia.
L‟attenzione sarà quindi focalizzata sul plasma atmosferico e sulla descrizione delle sue proprietà. Quindi saranno descritti diversi tipi di plasma atmosferico in base alle condizioni operative di alimentazione e delle loro strutture concentrando le nostre attenzioni verso le torce al plasma atmosferico basate sulle microonde.
Quindi si descriverà la realizzazione di una torcia al plasma atmosferico utilizzando i componenti a basso costo dei normali forni a microonde e con l‟obbiettivo di utilizzare questa torcia sia nel settore industriale che nella ricerca.
Tale torcia, realizzata con componenti commerciali domestici a basso costo, costituirà il cuore del prototipo di mini inceneritore che è stato progettato, realizzato, descritto e testato in laboratorio. Verrà quindi illustrata l‟efficacia di trattamento di materiale rappresentativo di rifiuti medicali come: carta, cotone idrofilo e tessuti organici biologici.
Infine verranno descritte le linee guida per gli sviluppi futuri del prototipo al fine di aumentarne l‟efficienza nel trattamento dei rifiuti, nel recupero dell‟energia derivante dalla combustione dei syn-gas e nella purificazione dei gas da agenti inquinanti.
Tesi master Acosta Gabriela
This document provides a thermo-mechanical design of a high power neutron converter for the SPIRAL2 Facility. It includes 3 key parts:
1. A description of the neutron converter design including the graphite neutron converter, cooling system, delay window, beam collimator, and other components.
2. Analysis of material activation, radiation damage effects, and lifetime considerations for the graphite and other materials used.
3. Thermo-mechanical design calculations for the 50kW and 200kW neutron converters including temperature distributions, stresses, and deformations to validate the design meets specifications. Testing results of graphite evaporation rates, delay window performance, and ball bearing performance are also summarized.
Tesi PhD Zhang Yan
This document is the dissertation of Zhang Yan for the degree of Ph.D. It summarizes his research on sputtering niobium films into RF cavities and sputtering of superconducting V3Si films. The dissertation contains 6 chapters that discuss sputtering techniques for niobium cavities, sputtering niobium films on an RFQ model, co-sputtering and reactive sputtering of V3Si films, and thermal diffusion of V3Si films. The research aimed to develop sputtering methods for producing superconducting coatings on RF cavities and investigate the properties of V3Si films for potential use in superconducting radio frequency applications.
Tesi federico della ricca
Preparazione di un protocollo di deposizione magnetron sputtering di films sottili di Nitruro di Titanio
Tesi master Vanessa Rampazzo
Creazione di un database di attacchi chimici ed elettrochimici per il trattamento superficiale di metalli e leghe ad uso industriale
Tesi master Paolo Modanese
Il forno in alto vuoto della TAV è stato costruito per l’Istituto Nazionale di Fisica Nucleare agli inizi degli anni novanta ed è installato presso i Laboratori Nazionali di Legnaro (PD) nello stabilimento Alte Energie.
E’ stato realizzato in collaborazione con la ditta milanese TAV, che ha sede a Caravaggio (MI), specializzata nella produzione di forni in vuoto. E’ stato così possibile realizzare un forno mai costruito prima e che rispondeva appieno alle esigenze richieste.
Il forno in vuoto allora in uso era un modello a caricamento orizzontale le cui pareti interne e le resistenze erano realizzate in grafite. Da allora il vecchio forno è stato congedato, mentre il nuovo impianto è entrato subito in funzione per eseguire le brasature e i trattamenti termici sulle cavità acceleratici superconduttive a quarto d’onda dell’impianto Alpi.
Da allora fino ad oggi, il nuovo forno è sempre stato operativo, e grazie ad esso è stato possibile realizzare una grande varietà di trattamenti termici e brasature, per le più svariate applicazioni e impieghi.
Tesi Master Diego Tonini
La tecnologia degli acceleratori di particelle è tradizionalmente un serbatoio da cui attingere per il trasferimento di conoscenze tecniche dall’ambito della ricerca di base all’industria; in questo campo i Laboratori Nazionali de Legnaro dell’Istituto Nazionale di Fisica Nucleare (LNL – INFN) vantano una lunga esperienza come ente di ricerca di alto livello sia in ambito italiano che internazionale, nello sviluppo di nuove tecniche di accelerazione e nell’applicazione di conoscenze e metodologie tipiche della scienza dei materiali al campo degli acceleratori di particelle. Il master in Trattamenti di superficie applicati a tecnologie meccaniche innovative per l’industria si inserisce in questo contesto e funge da ponte per il trasferimento del bagaglio di conoscenze maturate durante gli anni per il trattamento dei materiali delle cavità acceleratrici a realtà industriali presenti sul territorio nazionale.
Il trattamento superficiale di una cavità acceleratrice superconduttiva è un passaggio fondamentale nella sua realizzazione, in quanto predispone lo strato superficiale del risonatore stesso a sostenere le condizioni di vuoto, temperatura ed alti campi elettrici presenti durante il funzionamento nell’acceleratore; questi trattamenti presuppongono un’approfondita conoscenza della scienza dei materiali ed una robusta preparazione di tipo applicativo oltre che teorico.
Il lavoro di questa tesi prende l’avvio da due istanze fondamentali, cioè
dall’applicazione delle conoscenze fisiche, chimiche e meccaniche apprese nel corso del master e dalla tradizione nello sviluppo di nuove tecniche di accelerazione dei Laboratori Nazionali di Legnaro con il fine di realizzare e caratterizzare un nuovo tipo di strutture acceleranti basate sul concetto di cristallo fotonico o photonic band gap (PBG) applicato alle microonde.
Durante questo lavoro si sono quindi realizzati alcuni prototipi di cavità PBG risuonanti a 14 e 6 GHz, in rame ed in niobio superconduttivo, sviluppando un metodo realizzativo che permettesse di evitare il ricorso a costose saldature electron beam; le cavità così realizzate sono state trattate superficialmente adattando il protocollo di trattamento utilizzato per altre cavità costruite nei Laboratori e studiando nuove strade tecniche per la loro finitura superficiale. Infine si è proceduto ad adattare i sistemi criogenici e RF
integrandoli per caratterizzare le cavità costruite.Questo progetto si inserisce in una collaborazione fra i Laboratori Nazionali di Legnaro
e la sezione INFN di Napoli, che ha fornito il supporto teorico sulla teoria dei cristalli fotonici applicati agli acceleratori e ha contribuito al progetto delle cavità attraverso le simulazioni dei campi elettromagnetici in cavità; il gruppo di legnaro si è occupato, oltre che della costruzione, dei trattamenti di superficie e delle misure, anche della parte riguardante la superconduttività in Radiofrequenza.
Tesi Master Giorgio Keppel
L’obiettivo di questo lavoro consiste nella progettazione e costruzione di un sistema UHV multicamera per la deposizione di film sottili. La tecnica
utilizzata per crescere i ricoprimenti sottili in questo caso è l’arco catodico continuo e pulsato. Questa tecnica permette di depositare film di elevato spessore in tempi estremamente veloci. La sorgente è pressoché puntiforme in confronto allo sputtering ed i film possono essere più spessi e più puri.
L’arc vapour deposition è una tecnica di deposizione di film sottiliche cade nella grande famiglia del PVD. Essa consiste nella vaporizzazione, da un elettrodo, del materiale che si vuole depositare per mezzo di un arco. La tecnica è veloce, efficiente e relativamente poco costosa: di conseguenza è uno dei metodi più usati a livello industriale per ottenere deposizioni di film sottili con ottime proprietà meccaniche.
Negli ultimi anni si stanno effettuando numerose ricerche, sia sperimentali sia
teoriche, al fine di mettere in evidenza come questa tecnica possa essere molto utile per produrre dei film sottili in grado di aumentare le proprietà fisiche e chimiche dei rivestimenti (come ad esempio un aumento della densità, un miglioramento dell’adesione al substrato, della stechiometria dei composti e di ulteriori caratteristiche chimico-fisiche).
In particolare la letteratura russa tratta numerosi esempi di come la tecnica
dell’arco, proprio grazie all’alto grado di ionizzazione dei vapori prodotti, renda possibile la produzione di rivestimenti con determinate proprietà chimico-fisiche e strutturali per particolari condizioni di processo, non altrimenti ottenibili con altre tecniche competitive quali il magnetron sputtering o l’evaporazione tramite electron beam Come si vedrà in
seguito, infatti, l’arc vapour deposition ha il grandissimo vantaggio di controllare non solo la ionizzazione degli atomi che si vogliono depositare, attraverso una combinazione di campi elettrici e magnetici, ma anche l’energia con la quale gli ioni arrivano sul substrato.
Le sorgenti ad arco vengono inoltre utilizzate come sorgenti per LRQ EHDP che
devono produrre elevate densità di corrente.
Nel mondo industriale, infatti, questa tecnica riscuote molto interesse.Il deposito tramite arco catodico è un processo fisico sottovuoto che consente la
crescita di film duri, compatti ed aderenti su un ampio spettro di materiali al di sotto dei 300°C: Il film, estremamente sottile, ha durezze da 1000 a 3500 HV: le applicazioni industriali sono molte e variano dalla ricopertura di utensili da taglio agli tampi per le materie plastiche e lavorazioni meccaniche, da prodotti d’arredamento (maniglie, copri interruttori, pomoli, etc.) a componentistica da bagno (rubinetti, docce, tubi, etc.).
......
Tes master Tommaso Cavallin
Fu una scoperta sensazionale quando Jun Akimitsu e colleghi annunciarono la loro scoperta nel gennaio 2001 che il diboruro di magnesio diveniva superconduttore attorno ai 40 K. L’interesse degli autori era inizialmente rivolto verso il semiconduttore CaB6 , il quale diviene ferromagnetico a seguito di trattamento leggero di doping. La loro intenzione era quella di sostituire parzialmente degli atomi di carbonio con altri di magnesio, omologo come shells elettronici ma più leggero, e gli parve conveniente utilizzare il diboruro di magnesio (ben noto sin dal 1953) per questo scopo.
L’aspetto interessante è che il magnesio diboruro è un composto molto usato nelle reazioni di sintesi del boro, dei borani, o di bururi di metalli di transizione e facilmente reperibile in qualsiasi laboratorio di chimica. E’ dunque facile immaginarsi lo stupore del mondo scientifico quando fu
comunicato che il MgB2 diviene superconduttore a temperature mai raggiunte sino ad allora da sistemi basati su semplici leghe intermetalliche non ossidate. Le fievoli speranze ed il derivante
mitigato interesse che vi era attorno ai superconduttori all’inizio della seconda metà del 1900 era dovuto soprattutto a due figure ....
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Vlada pastushenko progress on fluorine-free electropolishing
- 1. LABORATORI NAZIONALI DI LEGNARO Progress on Fluorine-free Electropolishing Vlada Pastushenko, F. Stivanello, V. Palmieri 6thWorkshop on "Thin Films and New Ideas for SRF", Legnaro (PD) Italy, October 6-8 2014
- 2. Outline Ionic liquids, their properties and application. Electropolishing of Niobium in Fluorine-free solutions (first steps). Study the parameters of Electropolishing in Ionic Liquids. Procedure of standard electropolishing 6 GHz cavities. Development the systems for Electropolishing in Ionic Liquids: Different shapes of the cathode; Vertical system for EP 6 GHz cavity; Horizontal system for EP 6 GHz cavity. Q-factor result.
- 3. Deep Eutectic Solvent or DES* DES is a type of ionic solvent with special properties composed of a mixture which forms a eutectic with a melting point much lower than either of the individual components. The deep eutectic phenomenon was first described in 2003 for a mixture of choline chloride and urea in a 1:2 mole ratio, respectively. Choline chloride has a melting point of 302 °C and that of urea is 133 °C. The eutectic mixture melts lower than 100 ˚C. *Andrew Abbott; John Barron, Karl Ryder and David Wilson (2007). "Eutectic-Based Ionic Liquids with Metal-Containing Anions and Cations". Chem. Eur. J. 13: 6495– 6501. doi:10.1002/chem.200601738.
- 4. Four types of eutectic solvents: Type I Eutectic metal salt + organic salt (e.g. ZnCl2 + choline chloride) Type II Eutectic metal salt hydrate + organic salt (e.g. CoCl2*6H2O + choline chloride) Type III Eutectic organic salt + hydrogen bond donor (e.g. choline chloride + urea) Type IV Eutectic metal salt (hydrate) + hydrogen bond donor (e.g. ZnCl2 + urea)
- 5. Choline Chloride – based Ionic liquids Room Temperature 120˚C
- 6. Conductivity and viscosity of a Urea : Choline chloride mixture (2:1) as a function of temperature* *A. P. Abbott, G. Capper, D. L. Davies, R. Rasheed and V. Tambyrajah “Novel Solvent Properties of Choline Chloride/ Urea Mixtures” Chem. Commun, 2003, 70-71.
- 7. Electropolishing of Niobium in Fluorine-free solutions (first steps)
- 8. Organic solvents Ionic Liquids Acetonitrile tetramethylammonium perchlorate tetrabutylammonium perchlorate potassium perchlorate Dimethylformamide tetrabutylammonium perchlorate potassium perchlorate Urea Choline Chloride : Urea (1:2) tetramethylammonium perchlorate tartaric acid oxalic acid ammonium chloride Choline Chloride : Urea (1:3) ammonium chloride potassium tartrate Choline Chloride : Urea (1:4) ammonium chloride Choline Chloride: Ethylene Glycol (1:2) ammonium chloride M. Ceccato, “Elettropulitura del Niobio con Elettroliti a base di Liquidi Ionici”, Master Thesis (2007) University of Padua.
- 10. SEM analysis
- 11. Sulfamic acid – first success* *Rupp V. "Electropolishing of Niobium 6 GHz RF cavities in fluorine-free electrolyte", Master Thesis, 2009.
- 12. Influence of S and N containing compounds
- 13. Surface maps of different treatments raw Nb 10 min IL 10 min classical EP 60 min IL
- 14. Choline Chloride and Urea (1:4) with Sulfamic Acid (SA) and Ammonium Sulfamate (AmS) +30 g/l SA +50 g/l SA +75 g/l AmS +114 g/L AmS + 97 g/l SA
- 15. The Best parameters for EP Nb samples Choline Chloride : Urea 1 : 4 Sulfamic acid, g/l 97 Material cathode Nb Temperature, °C Higher then 120 Current density, A/cm2 0,3
- 16. Procedure of standard electropolishing 6 GHz cavities
- 17. Cavity kit appearance 1 4 2 3 1 – cavity; 2 – cathode; 3 – up flange; 4 – bottom flange
- 18. Stand for BCP and EP 1 – cavity; 2 – anode contacts; 3 – cathode contact; Blue indicator – direct flow, red – indirect.
- 19. EP result obtained in 6GHz cavity
- 20. Schematic diagram of an anodic polarization
- 21. Automatic software for controlling potential.
- 22. System for Electropolishing in Ionic Liquids
- 23. Electropolishing in Ionic Liquid (preliminary tests)
- 25. “Full holed” cathode Cut-off Cell
- 26. “Center holed” cathode Cut-off Cell
- 27. “Two parts” cathode 1 2 3 4 5 1 – cathode; 2 – flange; 3 – surface of cathode which has to be covered with Teflon ribbon; 4 – cavity; 5 – tube junction
- 28. Vertical system for EP 6GHz cavities in Ionic liquids
- 29. Scheme of flux direction ”inside cathode” 6GHz cavities treatment procedure IL EP process
- 30. Cavity after Vertical EP
- 31. Horizontal system for EP 6GHz cavities in Ionic liquids
- 32. Half cavity polished in horizontal position SEM Analysis Solution - 1:4 Choline :Urea, Sulfammic Acid - 1M/l; T- 120°C
- 33. Horizontal system for EP 6 GHz cavity* *O. Malkova, “Study of the Electropolishing of 6GHz Niobium cavity in ionic liquids”, Master Thesis, 2013.
- 34. Surface inside cavity after EP
- 35. Modified system for EP in Ionic liquids
- 36. Electropolishing of the Niobium: result after first try (60min) Iris Cell
- 37. Electropolishing of the Niobium: result after 6 hours
- 38. Q-factor result
- 40. Summary Choline Chloride - urea based Ionic liquids are a possible alternative to the hazardous standard electropolishing electrolyte based on hydrofluoric and sulphuric acid. The best solution that we found for Electropolishing of Niobium is Choline Chloride with Urea in ratio 1 to 4 with 1 M/l Sulfamic acid. The electropolishing in horizontal system give us shiny surface without pitting and damages and the result is reproducible.
- 41. Thank you for attention!
Editor's Notes
- After was decided to make try on light oxidizer. Choice fall down to Sulfamic acid and result was enough good so was performed series of tests to determine its influence on Nb anodic dissolution in 1-4 ChCl –urea melt
- in 1-4 ChCl – urea melt with 30 g/l SA with configuration a.