Impedance analysis of new PS internal dump design

The High Luminosity Large Hadron Collider (HL-LHC) project at CERN calls for increasing beam intensity in the injector chain. In the Proton Synchrotron (PS), a pre-injector of the LHC, these intensities can result in beam instabilities and potential RF heating of machine components, such that impedance mitigation measures are required. To study these intensity effects, the PS impedance model has been developed and is continuously updated. Each new machine element that is to be added into the accelerator requires an impedance study to minimize its contribution with respect to the machine's overall impedance budget. In such a context, this paper presents the impedance analysis of the new design of the internal beam dump for the PS, showing the design process required to reduce the impedance contribution of this element. Furthermore, the impedance analysis of the currently installed beam dump is analysed in order to compare the impedance contributions of the two designs

Prikazivanje kinetike sušenja šljive različitim varijantama krivih sušenja

This paper presents the experimental results of plum drying kinetics cv. ‘Čačanska Rodna’. Drying agents parameters were maintained constant the whole time for the duration (throughout) (of the) of the drying process. The study of kinetics of plum drying involved different characteristics of fresh fruits of plums (fruit weight , dry matter content, content of stone) which influence not only the duration of drying and fruit behavior over the process but and also the quality of prunes. The adopted method of examining the kinetics of drying allows continuous monitoring of changes in fruit weight and moisture content, on all trays, throughout drying. It was noted in the study that the drying kinetics of plum cultivar ‘Čačanska Rodna’ maintained at constant drying parameters depends on properties of fresh fruits.U ovom radu prikazani su eksperimentalni rezultati ispitivanja kinetike sušenja plodova šlјive sorte Čačanska rodna. Parametri agensa sušenja su održavani konstantnim u toku trajanja procesa sušenja. Ispitivanja kinetike sušenja šlјive vršena su za različite karakteristike svežih plodova (masa plodova, sadržaj suve materije plodova, sadržaj koštice u plodovima), koje utiču na vreme sušenja, ponašanje plodova u toku procesa sušenja i kvalitet suve šlјive. Usvojeni metod ispitivanja kinetike procesa sušenja omogućava stalno praćenje promena masa i vlažnosti plodova na svakoj lesi u toku procesa sušenja. Konstatovano je da kinetika procesa sušenja plodova sorte Čačanska rodna, pri konstantnim parametrima agensa sušenja, zavisi od karakteristika svežih plodova

Antiproliferativna aktivnost glutarimidnih derivata iz baze podataka Nacionalnog instituta za rak, SAD - 3D odnos strukture i aktivnosti nezavisan od poravnavanja molekula

Alignment-free, three dimensional structure-activity relationships (3D QSAR) of the antiproliferative potency of twenty-two glutarimide-containing compounds, taken from National Cancer Institute Developmental therapeutics Program database, toward eight representative human tumour cell lines are reported. The descriptors used in the QSAR study were derived from GRID molecular interaction fields. The obtained models readily detect structural motifs positively or negatively correlated with the potency of the studied compounds toward each cell line. In this way, the pharmacophoric pattern required for high potency of compounds is reported. This pattern can serve as guidance for the design and syntheses of novel congeners, planned to be tested toward human tumour cell lines.U tekstu je opisan odnos strukture i antiproliferativne aktivnosti 22 glutarimidna derivata prema osam reprezentativnih linija humanih tumora. Podaci o strukturi jedinjenja i njihovoj aktivnosti su preuzeti iz baze podataka Nacionalnog Instituta za rak, SAD. Deskriptori, nezavisni od poravnavanja molekula (GRIND-2), korišćeni u proučavanju odnosa strukture i aktivnosti su dobijeni upotrebom programa GRID. Modeli jasno prikazuju strukturne elemente jedinjenja koji se pozitivno ili negativno korelišu sa biološkom aktivnošću. Farmakoforna slika dobijena iz modela će biti korišćena za planiranje novih analoga koji sadrže glutarimidni prsten i za koje se očekuje da će pokazati značajnu antiproliferativnu aktivnost

Senzorni kvalitet trosortnih šljivovica

The paper presents the results of sensory analysis involving 6 monovarietal plum brandies (cultivars: Crvena ranka, Požegača, Dragačica, Stanley, Čačanska rodna and Čačanska lepotica) and 8 trivarietal plum brandies obtained by blending these cultivars, where all of the distinctive blands (coupages) had a 50% content of the brandy made from the Crvena ranka cultivar, combined with two of the other brandies, each represented with a 25% share. The blends (coupages) were produced using two methods – blending the monovarietal distillates either before or after the redistillation (with 4 brandies in each one). By forming the corrrespodning trivarietal blends, it is possible to obtain plum brandies which – apart from possessing a higher sensory quality than the monovarietal brandies – also constitute an excellent base for the production of supreme plum brandies.U radu su prikazani rezultati senzorne analize 6 monosortnih šljivovica (sorata Crvena ranka, Požegača, Dragačica, Stenlej, Čačanska rodna i Čačanska lepotica) i 8 trosortnih šljivovica dobijenih mešanjem ovih sorata, pri čemu je, u svim mešavinama (kupažima), sa 50% bila zastupljena rakija sorte Crvena ranka, a dve rakije od ostalih pomenutih sorata sa po 25%. Mešavine (kupaži) su proizvedene na dva načina – mešanjem monosortnih destilata pre ili nakon redestilacije (po 4 rakije). Formiranjem odgovarajućih trosortnih mešavina mogu se dobiti šljivovice koje imaju viši senzorni kvalitet od komponentnih monosortnih rakija, i koje su odlična osnova za proizvodnju vrhunskih šljivovica

Fabrication of the 0.346 THz BWO for Plasma Diagnostic

Nuclear fusion is probably the most demanding challenge the scientific community is facing. The plasma is a delicate material that has to be properly shaped to achieve a high efficiency fusion process. Unfortunately, the plasma is affected by micro-turbulences still not fully understood, detrimental for the reactor functioning. The diagnostic of plasma is a fundamental technique that needs advanced approaches for a full mapping of the plasma behavior. The 0.346 THz backward wave oscillator is the enabling devices for a high-k plasma diagnostic that will provide unprecedented insight on turbulences leading to full operational fusion reactors. This paper describes the final fabrication phase of the 0.346 THz BWO for plasma diagnostic jointly performed in an international project, involving three leading institutions in vacuum electronics

Fabrication of the 0.346 THz BWO for Plasma Diagnostic

Nuclear fusion is probably the most demanding challenge the scientific community is facing. The plasma is a delicate material that has to be properly shaped to achieve a high efficiency fusion process. Unfortunately, the plasma is affected by micro-turbulences still not fully understood, detrimental for the reactor functioning. The diagnostic of plasma is a fundamental technique that needs advanced approaches for a full mapping of the plasma behavior. The 0.346 THz backward wave oscillator is the enabling devices for a high-k plasma diagnostic that will provide unprecedented insight on turbulences leading to full operational fusion reactors. This paper describes the final fabrication phase of the 0.346 THz BWO for plasma diagnostic jointly performed in an international project, involving three leading institutions in vacuum electronics

THz backward-wave oscillators for plasma diagnostic in nuclear fusion

Understanding of the anomalous transport attributed to short-scale length microturbulence through collective scattering diagnostics is key to the development of nuclear fusion energy. Signals in the subterahertz (THz) range (0.1–0.8 THz) with adequate power are required to map wider wavenumber regions. The progress of a joint international effort devoted to the design and realization of novel backward-wave oscillators at 0.346 THz and above with output power in the 1 W range is reported herein. The novel sources possess desirable characteristics to replace the bulky, high maintenance, optically pumped far-infrared lasers so far utilized in this plasma collective scattering diagnostic. The formidable fabrication challenges are described. The future availability of the THz source here reported will have a significant impact in the field of THz applications both for scientific and industrial applications, to provide the output power at THz so far not available

Nanoscale surface roughness effects on THz vacuum electron device performance

Vacuum electron devices are the most promising solution for the generation of watt-level power at millimeter wave and terahertz frequencies. However, the three dimensional nature of metal structures required to provide an effective interaction between an electron beam and THz signal poses significant fabrication challenges. At increasing frequency, losses present a serious detrimental effect on performance. In particular, the skin depth, on the order of one hundred nanometers or less, constrains the maximum acceptable surface roughness of the metal surfaces to be below those values. Microfabrication techniques have proven, in principle, to achieve values of surface roughness at the nanometer scale; however, the use of different metals and affordable microfabrication techniques requires further investigation for a repeatable quality of the metal surfaces. This paper compares, for the first time, the nanoscale surface roughness of metal THz waveguides realized by the main microfabrication techniques. In particular, two significant examples are considered: a 0.346 THz backward wave tube oscillator and a 0.263 THz traveling wave tube

THz Backward-wave oscillators for plasma diagnostic in nuclear fusion

Summary form only given. The understanding of plasma turbulence in nuclear fusion is related to the availability of powerful THz sources and the possibility to map wider plasma regions. A novel approach to realize compact THz sources to be implemented in the plasma diagnostic at NSTX experiment (Princeton Plasma Physics Laboratory, USA) is reported.Two novel 0.346 THz Backward-Wave Oscillators (BWOs) have been designed and are presently in the fabrication phase. One BWO is based on the Double Staggered Grating (DSG) that supports a sheet electron beam to provide a high output power; the second BWO is based on the Double Corrugated Waveguide (DCW) that supports a cylindrical electron beam generated by a conventional Pierce gun. The performance of both the BWOs was computed by Particle-in-cells (PIC) simulations. The DSG-BWO provides about 1W of output power with a beam current of 10 mA and a beam voltage of 16.8 kV. The DCW-BWO provides 0.74W output power with 10 mA beam current and 13 kV beam voltage. The DSG and the DCW have been realized by state of the art prototype nano-CNC milling machine (DMG Mori-Seiki) that permits one to achieve performance, in term of cost and surface finishing, unavailable with any other technology. It is the first time that this technique is applied to structures above 0.3 THz. The high output power of both the BWOs demonstrates the importance of novel approaches in the emerging field of THz vacuum electron devices

Fabrication of 0.346 THz BWO for Plasma Diagnostics

Nuclear fusion energy is perhaps one of the most demanding challenges the scientific community is facing. Unfortunately, the plasma is affected by micro-turbulence, which is still not fully understood, but which can degrade plasma confinement. The 0.346 THz backward wave oscillator is the enabling device for a high-k plasma collective scattering diagnostic that will provide unprecedented insight on turbulence thereby contributing to the realization of fully operational fusion reactors. This paper describes the final fabrication phase of the 0.346 THz backward wave oscillator for the collective scattering diagnostic jointly performed in an international project, involving three leading institutions in vacuum electronics. The advancements in technology will open the route to new families of THz vacuum electron devices to enable new THz applications and provide industry with new advanced processes