Evaluation of a pulsed quasi-steady MPD thruster and associated subsystems

The performance of quasi-steady magnetoplasmadynamic (MPD) thrusters at high power levels is discussed. An axisymmetric configuration is used for the MPD thruster, with various cathode and anode sizes, over a wide range of experimental conditions. Thrust is determined from impulse measurements with current waveforms, while instantaneous measurements are made for all other variables. It is demonstrated that the thrust produced has a predominately self-magnetic origin and is directly proportional to the square of the current. The complete set of impulse measurement data is presented

Thermal stability and nitrogen redistribution in the〈Si〉/Ti/W–N/Al metallization scheme

Backscattering spectrometry, Auger electron spectroscopy, and x‐ray diffraction have been used to monitor the thin‐film reactions and nitrogen redistribution in the 〈Si〉/Ti/W–N/Al metallization system. It is found that nitrogen in the W–N layer redistributes into Ti after annealing at temperatures above 500 °C. As a consequence of this redistribution of nitrogen, a significant amount of interdiffusion between Al and the underlayers is observed after annealing at 550 °C. This result contrasts markedly with that for the 〈Si〉/W–N/Al system, where no interdiffusion can be detected after the same thermal treatment. We attribute this redistribution of nitrogen to the stronger affinity of Ti for nitrogen than W. If the Ti layer is replaced by a sputtered TiSi_(2.3) film, no redistribution of nitrogen or reactions can be detected after annealing at 550 °C for 30 min

Assignment Model-based and Integrated Process Improvement (Mipi) to Integrate Waste Management System in Tpst Bantargebang-bekasi, West Java- Indonesia

. The waste management in Bantargebang has been planned for 15 yearsand should be improved in order to meet the needs of the stakeholders. The studyis done to find the right method to be used for integrating the waste managementin Bantargebang site. The method is a review of previous studies related toimprovement in waste management and business processes. The result suggeststhat the mapping of the process needs to be done on the waste managementsystem and using the Model-Based Integrated Process Improvement (MIPI) whichdeveloped by Adesola et al. (2006) to improve the process

NUMERICAL AND EXPERIMENTAL MODELING OF INTERACTION BETWEEN A TURBULENT JET FLOW AND AN INLET

In ventilation devices to get rid of harmful substances out of workingplaces, we use sucking devices. The local sources of pollution are evacuated by them. Abasic element when creating the model of sucking device is: the source of harmful substancesis discussed as a rising convective flow, which is ejected out of sucking spectrum,created by a sucking apparatus. In the present work, the flow is a whole one with variablequantity of motion and kinetic energy along it's length. The change in those twoparameters is caused by and is in dependent function of the inlet spectrum. There hasbeen discussed a two-component flow of air and gas in ventilation devices. A two-velocityscheme of flow is used to realise the numerical method. An integral method of investigationis used, based on the conditions of conservation of mass contents, quantity of motion andkinetic energy. It's been accepted that quantity of motion and energy change in functionof inlet action. A comparison of numerical results and natural experiment are made fortwo conditions: full suck and not full suck. Conclusion is that the present model is preciseand can be unset for engineering calculations

Holsfjorden som ny drikkevannskilde for Oslo Oppdaterende undersøkelse av bakterier og vannkjemi i Holsfjorden

Årsliste 2000I forbindelse med planleggingen av Holsfjorden som ny drikkevannskilde for Oslo ble det i perioden oktober 1999 til januar 2000 gjennomført en undersøkelse av vannkvaliteten ved 5 stasjoner i Holsfjorden for å kartlegge konsentrasjon og utbredelse av sentrale drikkevannsparametre som tarmbakterier og utvalgte kjemiske stoffer. Undersøkelsen skulle bl.a. gi informasjon om optimalt inntaksdyp og inntakssted. Undersøkelsen ble foretatt før, under og etter høstfullsirkulasjonen da det gjerne er i denne perioden at man får mest forurensning inn i dypvannsinntak fra innsjøer. Prøvene ble tatt fra overflaten og ned til 150 m dyp, tilsammen 150 vannprøver som ble analysert på et 20 talls parametre. Vannkvaliteten var god på alle de 3 stasjonene på strekningen Toverud-Sønsterud. Inne ved Sylling i syd, og ut for Nes i nordre enden av Holsfjorden, var vannkvaliteten dårligere. Aller best var vannkvaliteten ved stasjon 3 Vefsrud og best ved 100 m dyp. Kraftig vindvær under sirkulasjonsperioden greide å bringe forurenset overflatevann ned til ca 50-60 m dyp. Ved stasjon 3 ble det ikke påvist termotolerant koliforme bakterier ved 100 m eller dypere i løpet av perioden. Presumptivt fekale streptokokker, og sulfittreduserende clostridier ble påvist av og til i lave konsentrasjoner (1-2 bakterier per 100 ml), hovedsakelig i overflatelagene etter vindvær. De aller fleste funnene av sistnevnte gruppe viste seg å være Clostridium perfringens. 100 m dyp ved de 3 midterste stasjonene tilfredsstilte normene for enkel vannbehandling i gjeldende drikkevannsforskrifter, og for de fleste parameterne også EU's drikkevanndirektiv. Et spørsmålstegn er det ved funnene av Clostridium perfringens. En sjelden gang kunne det påvises en og annen spore av denne også i dypvannet. Disse skal ikke være tilstede i rentvannet ut fra vannverkene etter EUs krav, og det er uklart om disse fjernes effektivt nok ved enkel vannbehandling.Oslo kommune, Vann og avløpsetaten (VAV

Computational Complexity of Atomic Chemical Reaction Networks

Informally, a chemical reaction network is "atomic" if each reaction may be interpreted as the rearrangement of indivisible units of matter. There are several reasonable definitions formalizing this idea. We investigate the computational complexity of deciding whether a given network is atomic according to each of these definitions. Our first definition, primitive atomic, which requires each reaction to preserve the total number of atoms, is to shown to be equivalent to mass conservation. Since it is known that it can be decided in polynomial time whether a given chemical reaction network is mass-conserving, the equivalence gives an efficient algorithm to decide primitive atomicity. Another definition, subset atomic, further requires that all atoms are species. We show that deciding whether a given network is subset atomic is in $\textsf{NP}$, and the problem "is a network subset atomic with respect to a given atom set" is strongly $\textsf{NP}$-$\textsf{Complete}$. A third definition, reachably atomic, studied by Adleman, Gopalkrishnan et al., further requires that each species has a sequence of reactions splitting it into its constituent atoms. We show that there is a $\textbf{polynomial-time algorithm}$ to decide whether a given network is reachably atomic, improving upon the result of Adleman et al. that the problem is $\textbf{decidable}$. We show that the reachability problem for reachably atomic networks is $\textsf{Pspace}$-$\textsf{Complete}$. Finally, we demonstrate equivalence relationships between our definitions and some special cases of another existing definition of atomicity due to Gnacadja

Confinement effect on solar thermal heating process of TiN solutions

We propose a theoretical approach to describe quantitatively the heating process in aqueous solutions of dispersed TiN nanoparticles under solar illumination. The temperature gradients of solution with different concentrations of TiN nanoparticles are calculated when confinement effects of the container on the solar absorption are taken into account. We find that the average penetration of solar radiation into the solution is significantly reduced with increasing the nanoparticle concentration. At high concentrations, our numerical results show that photons are localized near the surface of the solution. Moreover, the heat energy balance equation at the vapor-liquid interface is used to describe the solar steam generation. The theoretical time dependence of temperature rise and vaporization weight losses is consistent with experiments. Our calculations give strong evidence that the substantially localized heating near the vapor-liquid interface is the main reason for the more efficient steam generation process by floating plasmonic membranes when compared to randomly dispersed nanoparticles. The validated theoretical model suggests that our approach can be applied towards new predictions and other experimental data descriptions.Comment: 6 pages, 3 figures, accepted for publication in PCC