362 research outputs found

    Nova geokemijska metoda za razlikovanje prirodnih voda

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    Doneseni su rezultati vlastitih kemijskih analiza sadrfaja klcrida i sulfata nekih voda u nasemu priobalnom pojasu. Izneseni su argumenti, koji govore za to, da morska voda i kisnica zauzimlju poseban polofaj medu svim prirodnim vodama. Na temelju toga, i uz upotrebu bogate grade o kemizmu nasih rudnica, (Miholic) izradena je vlastita metoda prirodnoga razvrstavanja voda u osnovne geokemijske tipove, bazirana na funkciji: log [Cl-] = f (log [S042-]) U toku kruzenja na zemljinoj kori c1- i so42- obiljefavaju medusobnim omjerima koncentracija sve prirodne vode. To je iskoristeno u ovom radu i omogucilo je podijeliti sve vode u slije_ dece tipove: kiilnicki, marini, sulfatni i fosilni tip. Sulfatne vode predstavljaju antipodni tip fosilnim vodama. Vecina ostalih voda genetski su vezane istodobno na more i kiSnicu. Upotrebom prilozenih grafikona ponekada mozemo tumaciti historiju, starost i neke druge kvalitete prirodnih voda. Uoeena je i istaknuta okolnost, da su sulfati i kloridi posebno znacajne komponentesolnoga sastava svake prirodne vode i opcenitijeg su znacenja od ostalih komponenata mineralizacije voda. Iznesena je mogucnost daljnje razdiobe navedenih tipova voda uvodenjem novih varijabli

    A Modification of Teorell\u27s Method for Determining of Small Quantities of Ammonia

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    In Teorell\u27s method ammonia first reacts with sodium hyporbromite. The excess of the reagent is then used to decolorize the dyestuff, naphtyl-red, by means of which the analysis is made. Krogh applied the method to the analysis of ammonia in water and in the air but the author has encountered difficulties when using it

    Momentum distribution of a freely expanding Lieb-Liniger gas

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    We numerically study free expansion of a few Lieb-Liniger bosons, which are initially in the ground state of an infinitely deep hard-wall trap. Numerical calculation is carried out by employing a standard Fourier transform, as follows from the Fermi-Bose transformation for a time-dependent Lieb-Liniger gas. We study the evolution of the momentum distribution, the real-space single-particle density, and the occupancies of natural orbitals. Our numerical calculation allows us to explore the behavior of these observables in the transient regime of the expansion, where they are non-trivially affected by the particle interactions. We derive analytically (by using the stationary phase approximation) the formula which connects the asymptotic shape of the momentum distribution and the initial state. For sufficiently large times the momentum distribution coincides (up to a simple scaling transformation) with the shape of the real-space single-particle density (the expansion is asymptotically ballistic). Our analytical and numerical results are in good agreement.Comment: small changes; references correcte

    Fermi-Bose transformation for the time-dependent Lieb-Liniger gas

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    Exact solutions of the Schrodinger equation describing a freely expanding Lieb-Liniger (LL) gas of delta-interacting bosons in one spatial dimension are constructed. The many-body wave function is obtained by transforming a fully antisymmetric (fermionic) time-dependent wave function which obeys the Schrodinger equation for a free gas. This transformation employs a differential Fermi-Bose mapping operator which depends on the strength of the interaction and the number of particles.Comment: 4+ pages, 1 figure; added reference

    Anderson localization of a Tonks-Girardeau gas in potentials with controlled disorder

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    We theoretically demonstrate features of Anderson localization in the Tonks-Girardeau gas confined in one-dimensional (1D) potentials with controlled disorder. That is, we investigate the evolution of the single particle density and correlations of a Tonks-Girardeau wave packet in such disordered potentials. The wave packet is initially trapped, the trap is suddenly turned off, and after some time the system evolves into a localized steady state due to Anderson localization. The density tails of the steady state decay exponentially, while the coherence in these tails increases. The latter phenomenon corresponds to the same effect found in incoherent optical solitons

    Incoherent matter-wave solitons

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    The dynamics of matter-wave solitons in Bose-Einstein condensates (BEC) is considerably affected by the presence of a surrounding thermal cloud and by condensate depletion during its evolution. We analyze these aspects of BEC soliton dynamics, using time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory. The condensate is initially prepared within a harmonic trap at finite temperature, and solitonic behavior is studied by subsequently propagating the TDHFB equations without confinement. Numerical results demonstrate the collapse of the BEC via collisional emission of atom pairs into the thermal cloud, resulting in splitting of the initial density into two solitonic structures with opposite momentum. Each one of these solitary matter waves is a mixture of condensed and noncondensed particles, constituting an analog of optical random-phase solitons.Comment: 4 pages, 2 figures, new TDHFB result

    The single-particle density matrix and the momentum distribution of dark "solitons" in a Tonks-Girardeau gas

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    We study the reduced single-particle density matrix (RSPDM), the momentum distribution, natural orbitals and their occupancies, of dark "soliton" (DS) states in a Tonks-Girardeau gas. DS states are specially tailored excited many-body eigenstates, which have a dark solitonic notch in their single-particle density. The momentum distribution of DS states has a characteristic shape with two sharp spikes. We find that the two spikes arise due to the high degree of correlation observed within the RSPDM between the mirror points (xx and x-x) with respect to the dark notch at x=0x=0; the correlations oscillate rather than decay as the points xx and x-x are being separated.Comment: 9 pages, 8 figure

    Some Comparisons of Thermal Energy Consumption in a Temperature Versus a Subtropical Zone

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    Content: The aim of this desk study is to compare consumption of thermal energy in temperate vs. (sub)tropical climate for two representative processes: float heating (bating and dyeing) and chamber drying, with the view of contributing towards overall assessment of thermal energy consumption for tanneries operating under rather different conditions. The energy consumption is calculated for 1 t of wet salted hides and assuming that 1000 kg of wet salted weight corresponds to 1100 kg of pelt weight containing 838 kg of water and 262 kg of collagen subsequently segregated into grain leather and usable splits. Float rates (200% on pelt/shaved weight), average inlet water temperatures (15 oC vs. 25 oC), process float temperatures for bating (35 oC) and dyeing (60 o C) have been defined. Similarly, for computation of thermal energy for chamber drying, identical initial (45 %) and target leather humidity (20 %) are set and average respective fresh air temperature (15 oC vs. 30 oC) and fresh air relative humidity (50% vs. 70%) estimated and operating conditions such as exhaust air temperature and relative humidity defined. Based on such parameters and assumptions, specific ratios for thermal energy consumption for float heating (bating & dyeing) and for chamber drying have been calculated and comparisons made; the results might not quite coincide with common perceptions. The energy needs computed are net amounts, i.e. regardless of the source and without taking into account any losses and disregarding energy consumption for ambient heating and/or cooling. Thus, the total energy needs are much higher. The ratios computed for grain leather are valid for split leather as well. However, if the solar energy is used to support water heating, the conditions in the tropic zone are substantially more favourable, due to higher insolation and higher efficiency factor (i.e. difference of the final vs. inlet water temperature). Take-Away: Based on such parameters and assumptions, specific ratios for thermal energy consumption for float heating (bating & dyeing) and for chamber drying have been calculated and comparisons made; the results might not quite coincide with common perceptions. However, if the solar energy is used to support water heating, the conditions in the tropic zone are substantially more favourable, due to higher insolation and higher efficiency factor (i.e. difference of the final vs. inlet water temperature)
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