193 research outputs found
Dizajn modularnog sutava plastičnih euro paleta
Although pallet, as a tool, yields significant and widely recognized economic effects in production and distribution systems, it is still not fully utilized, indicating that it needs to be defined and developed as a specific product. Euro pallet product was designed using PRO/ENGINEER software system CAD module, as one of the most popular Cax systems, yielding a pallet of novel modular design that meets all the operational requirements of the existing range. The chosen material ensures high pallet longevity and durability, in line with the concept of sustainable development.Paleta kao sredstvo za rad ima izuzetan značaj i poznate ekonomske efekte u proizvodnim i distributivnim sustavima. Međutim, odnos prema paleti kao proizvodu, nije proporcionalan njenom ukupnom značaju. Obrazloženi aspekti neizostavno ukazuju na potrebe definiranja i razvoja palete kao specifičnog proizvoda. Dizajn proizvoda plastične euro palete je izveden u CAD modulu programskog sustava PRO/ENGINEER kao jednog od najpoznatijih CAx sustava. Dobijena je paleta novog modularnog koncepta koja ispunjava sve radne zahtjeve postojećih paleta. Izborom materijala je dobijena dugotrajnija paleta koncepta održivog razvoja
Dvije nukleozid-difosfat kinaze (NDPK/Nm23) iz morske spužve Suberites domuncula
Suberites domuncula is a member of the most ancient and simplest extant phylum of multicellular animals – sponges (Porifera). A database of S. domuncula expressed sequence tags (ESTs) was recently constructed by random cDNA sequencing. Two NDPK/Nm23 proteins from the sponge Suberites domuncula are reported here. Sponge proteins were named Nm23-SD1 and Nm23-SD6, because they display the highest sequence similarity with human Nm23-H1 and -H6 proteins. Overall sequence conservation of Nm23-SD1 with human Nm23-H1 is very high – 79 % (71 % identical amino acids). Nm23-SD6 possesses an insertion at the C-terminus and displays 55 % overall homology (40 % identical amino acids) with human Nm23 H6. Secondary structure predictions for both sponge and human Nm23 protein pairs are almost identical. S. domuncula Nm23 proteins display high similarity to homologues from mammals/humans, higher than to e.g. NDPK/Nm23 proteins from Drosophila or other invertebrates. Sponge Nm23 proteins are more similar to mammalian/human Nm23 proteins than most known Nm23 proteins of invertebrates.Suberites domuncula je pripadnik najstarije i najjednostavnije postojeće skupine (koljena) višestaničnih životinja – spužvi (Porifera). Nasumičnim sekvenciranjem cDNA S. domuncula nedavno je konstruirana baza EST-ova (expressed sequence tags). U ovom radu opisana su dva NDPK/Nm23 proteina iz spužve Suberites domuncula. Spužvini proteini nazvani su Nm23-SD1 i Nm23-SD6 jer su po aminokiselinskim sljedovima najslič niji ljudskim Nm23-H1 i -H6 proteinima. Ukupna sačuvanost sekvence izme|u Nm23-SD1 i Nm23-H1 vrlo je visoka i iznosi 79 % (71 % je identična). Nm23-SD6 ima inserciju na C-kraju i pokazuje ukupnu homologiju od 55 % (40 % identičnosti) s ljudskim Nm23-H6. Predikcija sekundarne strukture pokazuje da su oba proteinska para gotovo jednaka. Nm23 proteini iz spužve S. domuncula pokazuju visoku sličnost s homolozima iz sisavaca/čovjeka, višu nego s npr. NDPK/Nm23 proteinima iz vinske mušice ili drugih beskralješnjaka. Osim toga, sličniji su proteinima iz sisavaca/čovjeka od većine poznatih Nm23 proteina iz beskralješnjak
A new method for imaging nuclear threats using cosmic ray muons
Muon tomography is a technique that uses cosmic ray muons to generate three
dimensional images of volumes using information contained in the Coulomb
scattering of the muons. Advantages of this technique are the ability of cosmic
rays to penetrate significant overburden and the absence of any additional dose
delivered to subjects under study above the natural cosmic ray flux.
Disadvantages include the relatively long exposure times and poor position
resolution and complex algorithms needed for reconstruction. Here we
demonstrate a new method for obtaining improved position resolution and
statistical precision for objects with spherical symmetry
Electron-ion recombination of Si IV forming Si III: Storage-ring measurement and multiconfiguration Dirac-Fock calculations
The electron-ion recombination rate coefficient for Si IV forming Si III was
measured at the heavy-ion storage-ring TSR. The experimental electron-ion
collision energy range of 0-186 eV encompassed the 2p(6) nl n'l' dielectronic
recombination (DR) resonances associated with 3s to nl core excitations, 2s
2p(6) 3s nl n'l' resonances associated with 2s to nl (n=3,4) core excitations,
and 2p(5) 3s nl n'l' resonances associated with 2p to nl (n=3,...,infinity)
core excitations. The experimental DR results are compared with theoretical
calculations using the multiconfiguration Dirac-Fock (MCDF) method for DR via
the 3s to 3p n'l' and 3s to 3d n'l' (both n'=3,...,6) and 2p(5) 3s 3l n'l'
(n'=3,4) capture channels. Finally, the experimental and theoretical plasma DR
rate coefficients for Si IV forming Si III are derived and compared with
previously available results.Comment: 13 pages, 9 figures, 3 tables. Accepted for publication in Physical
Review
Social media and community policing implementation in South Eastern Europe : a question of trust
At the present time, social media are increasingly used within community policing as a tool of fostering communication, and improving trust between the police and communities. Community policing programmes implemented in post-communist countries in South Eastern Europe, as well as processes of building police legitimacy in general, have been facing challenges related to insufficient public confidence in the law enforcement, and a necessity to re-define police roles. This paper uses the results of empirical research to argue that the still ongoing processes of bridging gaps in police-community communication can be supported by the use of social media. Presented argumentation is based on the analysis of selected quantitative studies on police legitimacy, and chosen findings of qualitative field research which was conducted in 2016 in Bosnia and Herzegovina as a part of the project Community-Based Policing and Post-Conflict Police Reform (ICT4COP). An implication of presented study should be a more in-depth analysis of key factors influencing both the formation of police legitimacy, and ways in which the use of social media in police–community relations, especially, in post-communist societies, should be designed to serve the purpose of building trust in the police
The Halo Mass Function: High-Redshift Evolution and Universality
We study the formation of dark matter halos in the concordance LCDM model
over a wide range of redshifts, from z=20 to the present. Our primary focus is
the halo mass function, a key probe of cosmology. By performing a large suite
of nested-box N-body simulations with careful convergence and error controls
(60 simulations with box sizes from 4 to 256 Mpc/h, we determine the mass
function and its evolution with excellent statistical and systematic errors,
reaching a few percent over most of the considered redshift and mass range.
Across the studied redshifts, the halo mass is probed over 6 orders of
magnitude (10^7 - 10^13.5 M_sun/h). Historically, there has been considerable
variation in the high redshift mass function as obtained by different groups.
We have made a concerted effort to identify and correct possible systematic
errors in computing the mass function at high redshift and to explain the
discrepancies between some of the previous results. We discuss convergence
criteria for the required force resolution, simulation box size, halo mass
range, initial and final redshift, and time stepping. Because of conservative
cuts on the mass range probed by individual boxes, our results are relatively
insensitive to simulation volume, the remaining sensitivity being consistent
with extended Press-Schechter theory. Previously obtained mass function fits
near z=0, when scaled by linear theory, are in good agreement with our results
at all redshifts, although a mild redshift dependence consistent with that
found by Reed and collaborators exists at low redshifts.Comment: 20 pages, 15 figures. Minor changes to the text and figures; results
and conclusions unchange
Capturing Halos at High Redshifts
We study the evolution of the mass function of dark matter halos in the
concordance LCDM model at high redshift. We employ overlapping
(multiple-realization) numerical simulations to cover a wide range of halo
masses, 10^7-10^{15}h^{-1}M_\odot, with redshift coverage beginning at z=20.
The Press-Schechter mass function is significantly discrepant from the
simulation results at high redshifts. Of the more recently proposed mass
functions, our results are in best agreement with Warren et al. (2005). The
statistics of the simulations -- along with good control over systematics --
allow for fits accurate to the level of 20% at all redshifts. We provide a
concise discussion of various issues in defining and computing the halo mass
function, and how these are addressed in our simulations.Comment: 4 pages, 3 figure
Obtaining material identification with cosmic ray radiography
The passage of muons through matter is mostly affected by their Coulomb
interactions with electrons and nuclei. The muon interactions with electrons
lead to continuous energy loss and stopping of muons, while their scattering
off nuclei lead to angular 'diffusion'. By measuring both the number of stopped
muons and angular changes in muon trajectories we can estimate density and
identify materials. Here we demonstrate the material identification using data
taken at Los Alamos with the Mini Muon Tracker.Comment: 10 pages, 9 figures, Accepted to AIP Advance
A Numerical Model for Brownian Particles Fluctuating in Incompressible Fluids
We present a numerical method that consistently implements thermal
fluctuations and hydrodynamic interactions to the motion of Brownian particles
dispersed in incompressible host fluids. In this method, the thermal
fluctuations are introduced as random forces acting on the Brownian particles.
The hydrodynamic interactions are introduced by directly resolving the fluid
motions with the particle motion as a boundary condition to be satisfied. The
validity of the method has been examined carefully by comparing the present
numerical results with the fluctuation-dissipation theorem whose analytical
form is known for dispersions of a single spherical particle. Simulations are
then performed for more complicated systems, such as a dispersion composed of
many spherical particles and a single polymeric chain in a solvent.Comment: 6 pages, 8 figure
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