Vapors

The article discusses effective ways to reduce the cost of operating vapor recovery units and increase the financial result of their operation. The first method is based on regulation of the power-on time of the installation. The second method is based on using the potential energy of the fluid flow of the gravity section to supply the system equipment with energy. The potential savings on VRU maintenance will reduce the risks of payback of installations. The proposed methods will have a significant impact on society, as the possibility of a wider distribution of installations that protect the environment from emissions of volatile organic compounds into the atmosphere will become available.

In recent data on neutron induced acoustic cavitation in deuterium--containing liquids obtained by neutron measurements it was shown that very high temperatures could arise in some special cases. To study temperature of so--called bubble plasma it is desirable to have micro--detectors of X-rays, which can be prepared on the basis of room--temperature semiconductor detectors, in particular on mercuric iodide ($\alpha$--HgI$_2$) crystals. Having in view this aim, the properties of gel--grown ($\alpha$--HgI$_2$) crystals was studied by means of isothermal currents, and trap parameters was estimated. Results are promising for special aim of preparing X-ray detectors with moderate energy resolution needed in bubble--plasma diagnostic, though improving of crystal growing technology is necessary. {\it PACS:} 29.40.Wk; 52.70.La {\it Keywords:} X-ray and gamma--ray measurements; semiconductor detectors; mercuric iodide; plasma diagnostics; cavitation

The aim of the article is the review of two phase flow pattern maps for horizontal tubes. The flow pattern in evaporation and condensation section in a small tube has been analyzed ín this article. The two-phase flow pattern map for evaporation is proposed by Wojtan et al. while the condensation section is proposed by Thome and El Hajal. The simulation was in MathCAD and the results are presented in diagrams. In the simulation refrigerant R134a was used. Nomenclature d diameter (m) x vapor quality (-) G mass velocity (kg/sm) m mass flow rate (kg/s) p pressure (Pa) Q heat flux (W/m) T temperature (K) f friction factor (-) A area of tube (m) Greeks  heat transfer coefficient (W/mK)  thermal conductivity (W/mK)  void fraction (-)  dynamic viscosity (Ns/m)  surface tension (-)  density (m/kg) Index l liqued v vapor tp two phase

The impact of emissions from the fuel and energy sectors adversely affects the environment on the economies of countries. One of these pollutants is volatile organic compounds (VOC), which contribute to the formation of tropospheric ozone. Emissions of hydrocarbon formation in the form of volatile organic compounds occur in four stages of the fuel and energy industry sector: 1) production; 2) processing; 3) transportation; and 4) storage. The oil and gas industry ranks among the top polluting industries in terms of VOC emissions. Research of the negative impact of VOCs, as well as CO 2 emissions from the consequences of the extraction, processing, transport, and storage of oil and gas on the ecosystem of the planet and the population, has begun to be studied by science recently. Typically, these studies were conducted using laboratory and field analyses, as well as using data on anthropogenic emissions in the development of regulatory documents and requirements governing the control of VOC and CO2 emissions in the oil and gas industry.

ABSTRACTThis work is devoted to microwave heating of graphite for studying the processing of carbon nanotubes (CNTs) by graphite vaporization. We have applied heating by microwaves (MW) (power 800W, frequency 2.45 GHz) in air at 20–90 min. The oven temperature was approximately 1200°C. The condensed material was collected on a fused silica target. After deposition, the morphology of carbon nanotubes was studied by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM). The samples were found to contain nanotubes, nanoparticles and fibers (at 1.30–2.80 micrometers to 6–11 micrometers) which appeared to be highly graphitized. It was observed that multi-walled nanotubes (MWNT's) were produced by this method.

The aim of this work was to modelling the moisture sorption isotherm of the Rhecktophyllum Camerunence (RC) fiber at 23 by using the BET, GAB and DLP models. The fibers samples of 0.1g were submitted to hygro-thermal ageing in an environmental enclosure of 23%, 54% and 75% relative humidities at 23°C in accordance with NF EN ISO 483: 2006-01 standard. After 7 hours of exposure the equilibrum moisture was reached and gravimetric measurements were achieved on the specimens. The maximum moisture content was calculated. Their isotherms were modelled by interpolating the experimental datas of the maximum water content as a function of the relative humidity with the BET, GAB and DLP equations. The isotherms presented the sigmoid shape of type II. The parameters of those mathematical models were also deduced and the goodness of fit have been evaluated. The DLP model gave an excellent adjustment.

Mobile Robot Enabled Detection of Explosives and Biological Agents Gregory W. Auner1, Abhilash Pandya1, Golam Newaz1, Grant Gerhart2, Greg Hudas2 ... 1 GK Kannan, JC Kappor, Adsorption studies of carbowax and poly dimethyl siloxane to use as chemical array for nitro ...

The thermal effects which affect the development of leading edge cavitation in an inducer were investigated experimentally using refrigerant R114. For different operating conditions, the evolution of the cavity length with the cavitation parameter was determined from visualizations. The tests were conducted up to two-phase breeding. The comparison of tests in R114 and in cold water allowed us to estimate the amplitude of the thermodynamic effect. The results show that the B-factor depends primarily upon the degree of development of cavitation but not significantly upon other parameters such as the inducer rotation speed or the fluid temperature, at least in the present domain of investigation. These trends are qualitatively in agreement with the classical entrainment theory. In addition, pressure fluctuations spectra were determined in order to detect the onset of cavitation instabilities and particularly of alternate blade cavitation and rotating cavitation. If the onset of alterna...

Defense Advanced Research Project Agency's (DARPA's) thermal ground plane (TGP) effort was aimed at combining the advantages of vapor chambers or two-dimensional (2D) heat pipes and solid conductors by building thin, high effective thermal conductivity, flat heat pipes out of materials with thermal expansion coefficients that match current electronic devices. In addition to the temperature uniformity and minimal load-driven temperature variations associated with such two phase systems, in their defined parametric space, flat heat pipes are particularly attractive for Department of Defense and commercial systems because they offer a passive, reliable, light-weight, and low-cost path for transferring heat away from high power dissipative components. However, the difference in thermal expansion coefficients between silicon or ceramic microelectronic components and metallic vapor chambers, as well as the need for a planar, chip-size attachment surface for these devices, has limi...

Kontejnerski transport u kojem najvažniju ulogu imaju kontejnerski brodovi, ključna su stavka u svjetskoj trgovinskoj razmjeni. 70 % svjetskog i 90 % generalnog tereta prevozi se kontejnerima. Svijet kakav danas znamo nezamisliv je bez kontejnerskog transporta, a nova tehnologija koja bi u budućnosti zamijenila kontejnere nije na vidiku. Nove generacije kontejnerskih brodova su sve veće u svojim dimenzijama i kapacitetu, a mjere za ispuštanje ispušnih plinova su sve strože. Brodari su pronašli rješenje kako graditi kontejnerske brodove enormnih veličina, a pritom smanjiti udio ispušnih plinova na minimum. Rješenje je korištenje prirodnog ukapljenog plina kao gorivo umjesto dizela i teškog goriva. U ovom radu opisane su nove generacije kontejnerskih brodova na LNG pogon u smislu konstrukcijske izvedbe, izvedbe samog pogona, te prirodnog ukapljenog plina kao gorivo.Container transport, in which container ships play the most important role, is a key item in world trade. 70 % of world a...

U ovom diplomskom radu opisane su vrste bodova u pomorskom prometu te u koje skupine brodova spadaju. U glavnom djelu rada opisati ćemo elektroenergetski sustav jednog od brodova. Veći dio će biti posvećen samom pogonu i njihovoj izvedbi. Spomenuti ćemo brodske instalacije i rezervne pogone koji su bitni u slučajevima u nuždi te za vrijeme popravaka i testiranja samog generatora i ostatka pogona. Shemama će biti prikazano spajanje brodova sa obalom i dati ćemo kratki opis toga. Prije kraja ćemo posvetiti pažnju brodu Qeen Mary 2 te kasnije zaključiti koje vrste brodova su pogodnije za koju izvedbu samog pogona tj. Elektroenergetskog sustava.This graduate work describes the types of ships in maritime traffic and in which groups of ships they belong. In the main work we will describe Electrical Power Load Analysis of one of the ships. Most will be dedicated to the drive itself and their performance. We will mention ship installations and backup drives that are essential in emergency s...

Detailed measurements have been made in a high pressure, adiabatic (boiled at the inlet) annular flow in a narrow, high aspect ratio duct using a gamma densitometer, hot-film anemometer and high-speed video photography. Measurements of void fraction, droplet frequency, velocity, drop size, and interfacial area concentration have been made to support the three-field computational capability. An important aspect of this testing is the use of a modeling fluid (R-134a) in a vertical duct which permits visual access in annular flow. This modeling fluid accurately simulates the low liquid-to-vapor density ratio of steam-water flows at high pressures. These measurements have been taken in a narrow duct of hydraulic diameter 4.85 mm, and a cross-section aspect ratio of 22.5. However, the flow displays profiles of various shapes not only in the narrow dimension, but also in the width dimension. In particular, the shape of the void profiles depends on the entrained droplet flux from the edges...

The main motivation of conducting this work is to present a rigorous analysis and investigation of the potential effect of the heat pipe adiabatic region on the flow and heat transfer performance of a heat pipe under varying evaporator and condenser conditions. A two-dimensional steady-state model for a cylindrical heat pipe coupling, for both regions, is presented, where the flow of the fluid in the porous structure is described by Darcy–Brinkman–Forchheimer model which accounts for the boundary and inertial effects. The model is solved numerically by using the finite volumes method, and a fortran code was developed to solve the system of equations obtained. The results show that a phase change can occur in the adiabatic region due to temperature gradient created in the porous structure as the heat input increases and the heat pipe boundary conditions change. A recirculation zone may be created at the condenser end section. The effect of the heat transfer rate on the vapor radial v...

The microscale transport processes in droplet condensation and removal due to interfacial phenomena were studied. In particular, this paper concerns the movement of a condensed ethanol sessile drop into a concave liquid film in the corner. An improved image analyzing procedure was used to evaluate the curvatures and contact angles for both the drop and the concave corner meniscus at different condensation rates. The experimental results demonstrated that the condensate removal rate was a function of the curvature and contact angle, which self-adjust to give the necessary force field. The use of a dimensionless, shape dependent, force balance was demonstrated. For small drops, the intermolecular force was found to be much larger than the gravitational force and dominated droplet removal. Microscale pressure fields can be experimentally measured whereas interfacial temperature differences cannot.

A numerical method based on the SIMPLE algorithm has been developed for the analysis of vapor flow in a concentric annular heat pipe. The steady-state response of a concentric annular heat pipe to various heat fluxes in the evaporator and condenser sections are studied. The fluid flow and heat transfer in the annular vapor space are simulated using Navier-Stokes equations. The governing equations are solved numerically, using finite volume approach. The vapor pressure and temperature distributions along a concentric annular heat pipe are predicted for a number of symmetric test cases. The vapor flow reversal and transition to turbulence phenomena are also predicted. The results are compared with the available numerical data and have shown good agreement in all cases. Therefore, the vapor flow model developed in this paper has shown good accuracy and convergence behavior in the range of low to moderate radial Reynolds numbers.

This article explores the ways in which the contemporary legacies of the Cheju Massacre are intergenerationally transmitted and ritually reenacted in postmemory practices involving spirit possession and the reburial of dead bodies after exhumation. It inquires into questions of violence, memory, silence, and memorialization with resspect to a formative historical event, the Cheju Massacre, or the Cheju April 3 Event in 1948, which is regarded by scholars as the direct precursor of the Korean War, one of the first outbreaks of violent ideological conflict in the early Cold War. More specifically it examines contestations over the meaning of mass death and social suffering in the divergent works of personal, family, and official memories of the violent events and their aftermath.

The sorption of vapors by cellulose samples and by some cellulose derivatives was studied at 25 oC. To describe sorption isotherms, a thermodynamic equation was proposed: A=Ao/[1-(RT/g)lnφ], where Ao is maximal sorption value, φ is relative pressure of vapors, and g is specific thermodynamic potential. Depending on the g -value, this equation can describe isotherms of various shapes that occur for cellulose and its derivatives. Application of the equation makes it possible to calculate such structural characteristics of the polymers as accessible specific surface and crystallinity, as well as the substitution degree of cellulose derivatives. Moreover, amounts of monomolecular and multimolecular fractions of the sorbate can be determined.

The heat pipe though has a wide application; the information available towards the development of an efficient heat pipe is seldom seen in the open literature. In the present study, investigations are carried out for optimizing the fluid inventory in a typical heat pipe. A "flooded" (with exceedingly large amount of working fluid) heat pipe has slow response and has limited lower range of operation in terms of operating temperature. On the other hand, "starving" (with too little amount of working fluid) heat pipe although exhibits fast response to heat loads, shows severe limit at high temperature conditions. In the present study, an attempt is made to design, fabricate and test a miniature heat pipe with 5 mm diameter and 150 mm length with a thermal capacity of 10 W. Experiments were conducted with and without working fluid for different thermal loads to assess the performance of heat pipe. The working fluids chosen for the study were same as those commonly use...

This experimental and analytical study focuses on the formation of banded condensate films on a horizontal tube, when the ammonia mass fraction of the vapor is less than 0.0126. The experimental results show that there is a step change in the heat transfer coefficient when a banded film is formed. This change develops when the vapor mass fraction is approximately 0.004 and the heat transfer coefficient at the end of the change is 15% greater than the value expected for steam. The banded films are initiated at the base of the tube; midway between the regions where droplets detach. Photographs taken during the tests show that the development starts with the formation of a single band; when this band is complete, secondary bands are formed on either side and then further bands are added until the complete tube surface is covered with a banded film. The reason for the delay in the formation of the bands is examined using a simple two-dimensional force balance. The success of this examin...

Brodski dizelski motor je složen multivarijabilni neli-nearni dinamički sustav. Njegova osnovna struktura se sastoji od međusobno povezanih podsustava i velikog broja različitih komponenti, te se kvarovi mogu pojavi-ti na bilo kojoj komponenti sustava. Stoga, za pobolj-šanje pouzdanosti i sigurnosti brodskih strojnih susta-va metode dijagnostike kvarova imaju sve veću i veću važnost. Ovaj rad pruža poseban osvrt na dijagnostič-ke metode zaključivanja u funkciji pravovremene lo-kalizacije i izolacije kvarova. Analiza stabla kvarova prikazuje sve uzroke neispravnog rada separatora teš-kog goriva. Analiziran je utjecaj nečistoća u gorivu na okoliš i moguće kvarove u sustavu goriva kao izravna posljedica neispravnog rada separatora. Kvarovi u su-stavu goriva su izvedeni na brodostrojarskom simula-