Biggest Flow Research Articles

The Calculus of the Operation Parameters at Pressure of the Primary Separation Column of the 15N Production Plant

The relations for calculus of: 10M HNO3 solution flow, isotopic transport, 15N molar fraction at the bottom of the separation column, product flow, interphasic transfer velocity, height equivalent to the theoretical plate and sulfur dioxide flows in both stages of the product refluxer are presented for 15N separation column with different diameters and 10M HNO3 feeding flow rates, operated at pressure up to 1.5 atm. In order to produce the isotope 15N at 99 at. % 15N by isotopic exchange in Nitrox system it is desirable to operate the production plant at biggest flow of 10M HNO3 solution, which allows the 15N production at that concentration on a given plant. That will be possible by operating the plant at pressure as it is shown in this work. At 0.8 atm pressure (1.8 atm absolute) the isotopic separation at higher flow rates would be practically equal with that obtained at lower flow rates and atmospheric pressure. For constant: HETP = 10.85 cm, 15N molar fraction of the feeding 10M HNO3, Nf = 0.00365, and of the product, Np = 0.12, the variation of the primary separation column product and of the 15N production plant, as a function of the feeding flow with 10M HNO3 solution, are also presented.

Hydrologial regime of the river Uda and its use for water management years (within Kharkiv region)

Formulation of the problem. Water is the basis of life. Nowadays, with the development of science and technology, man engages more and more types of natural resources in the process of material production which enable the production of goods necessary for life. Water is one of the most important among these natural resources. Therefore, water resources are constantly monitored and accounted at the state level. However, at the regional level (regions and districts), this issue still needs several studies, expertise and evaluation work. Relevant questions remain concerning the calculation of the hydrological regime as a whole in Kharkiv region, and in individual rivers. The purpose of the article is to study the hydrological regime of surface waters of the river Uda (within Kharkiv region) for 30 years and inner- annual flow distribution in the middle of the year for various practical purposes. Presentation of the main material. The features of the river Uda flow for 30 years are considered in the article. Examining the hydrological regime of the river, it has been found out that the distribution of water flow in the river is uneven throughout the year and this is due to climatic conditions (mainly rainfall and temperature). Analyzing the distribution of flow by seasons, it can be noticed that for the Uda river near the settlement Peresichna spring runoff is 54.3%, while in summer and winter - 10.5% and 24.3%, respectively; near the settlement Bezlyudivka spring runoff is 36.3%, while in summer and winter - 20.2% and 25.11%, respectively. Rivers are fed primarily by snow with a relatively high degree of soil runoff compared to rain. The deepest water flowing years in the river Uda (within Kharkiv region) during the period from 1981 to 2010 were 1981 - 1983, dry years were 2007 – 2010. Inner-annual runoff was calculated for the purpose of water supply, so summer - autumn and winter were taken as a limiting period, and winter – as a limiting season. Conclusions. It has been found out that the biggest flow by the limiting period on the territory of the Uda basin was in 1981, and the lowest flow - in 2009, the lowest flow by the limiting season - r. Uda (settlement Bezlyudivka) was in 2010, in the Uda river at settlement Peresichna - in 2003. Thus, in consequence of inner- annual flow calculations, we can determine potential water intake rate for the particular year which is very important in terms of ecology.

Impact of Coffee Grounds Addition on the Calorific Value of the Selected Biological Materials

Abstract The objective of the paper was, inter alia, to determine the impact of coffee grounds on the heat of combustion of their combination with other biological materials. Research on the heat of combustion and calculations of the calorific value were carried out with the use of a KL-12 Mn calorimeter according to the technical specifications and standards PN-81/G–04513 i PN-ISO 1928:2002. Coffee grounds, tea grounds, pine wood and yellow wheat straw were used in the research. The heat of combustion of particular substrates was determined and then their mixtures with coffee grounds in the following proportion were prepared: 75% substrate – 25% coffee grounds, 50% substrate – 50% coffee grounds, 25% substrate – 75% coffee grounds. Calorific value of particular substrates was increasing with the amount of added coffee grounds. Their biggest flow was reported in the mixture of 50%/50% of coffee grounds and wheat straw and the smallest in case of coffee grounds and wood on account of a similar calorific value of both substrates.

Logistic Constraints as a Part of a Sustainable Medical Waste Management System

In a Medical Waste Management System (MWMS), logistic issues have a significant importance due to medical waste characteristics that have an influence on transport restrictions, storage possibilities and safety reasons. This paper focuses on logistic determinants in a MWMS, taking into account existing legal requirements, organizational factors and economic aspects (on the example of Poland). Problems associated with effective logistics are essential for the quality and safety of a MWMS and these issues seem to be still undervalued. In Poland, there is approximately 40 thousand waste generators and each year they produce on average 45 thousand tons of medical waste, of which more than 90% is classified as infectious. The biggest flow comes from hospitals and large health care units; other sources are private medical practices, research units, hospices and pharmacies. All units generating medical waste must comply with strict requirements for the collection, storage and disposal, particularly with regard to infectious waste. In view of the above, organizational structure should include goals and constraints of MWMS in order to implement them in real-world conditions The framework for sustainable operation of a MWMS is efficient logistics of waste and balance in the link between waste generation units and treatment facilities.

Investigation on Non-Premixed Swirling Flame in a Multi-Hole Burner

This paper focuses on investigating the flow structures in a multi-hole swirl burner. Using the Particle Image Velocimetry(PIV) technique, the experiment measured the velocity distributions of the swirling flame in a muti-hole burner. The experiments show that there is a central recirculation zone (CRZ) in the middle of the flow field, and two counter-rotating vortices exist along the centerline symmetrically. With fuel jet increase: the width of recirculating zone and axial mean velocity peaks changes little; length of recirculation zone and the biggest reverse flow velocity increases; the expansion angle of swirling jet increase at first, and then changes little; axial non-uniform coefficient of outlet reduces at first, and then increases. With airflow velocity increase: axial mean velocity peaks increase; the dimension of recirculating zone and the expansion angle of swirling jet are unchanged; axial non-uniform coefficient of outlet increases.The data from this experiment is helpful for optimization of the swirl burner design, and can be established as benchmarks for the development and validation of swirl combustion numerical simulations.

Influence of the Amazon River runoff on the tropical atlantic

The Amazon river has the biggest flow in the world, 0.2 Sv (1 Sv = 106 m3/s), and is responsible for a large part of the low Sea Surface Salinity (SSS) in the west tropical Atlantic ocean. Very few Ocean General Circulation Model (OGCM) include runoff which brings a specific contribution to the Ocean physics. Comparison of simulations with constant or monthly runoffs shows that the spread of the Amazon fresh waters offshore of the north Brazilian coast is controlled by the ocean circulation and not by the Amazon flow. Therefore, in the model like in the observations, SSS minimum is observed in summer three months after the Amazon flood. In agreement with observations, a thick (more than 40 m) Barrier Layer (BL) is present every summer north of the Amazon mouth. Because of the strong and shallow salinity gradient associated with the Amazon freshwater, an important part of the solar radiation is trapped in the BL and creates an inversion of the vertical gradient of temperature. However with this forced model, BL does not seem to have a clear impact on SST and so on the air-sea interaction. Freshwater flux is also able to bend the sea surface. The geostrophic part of the North Brazilian Current (NBC) retroflection is then lightly weaker in presence of the Amazon runoff.

The size of the singular set in mean curvature flow of mean-convex sets

In this paper, we study the singularities that form when a hypersurface of positive mean curvature moves with a velocity that is equal at each point to the mean curvature of the surface at that point. It is most convenient to describe the results in terms of the level set flow (also called “biggest flow” [I2]) of Chen-Giga-Goto [CGG] and Evans-Spruck [ES]. Under the level set flow, any closed set K in R generates a one-parameter family of closed sets Ft(K) (t ≥ 0) with F0(K) = K. If the boundary of K is a smooth compact hypersurface, then so is the boundary of Ft(K) for t in some interval [0, ), and for such t’s the evolution coincides with motion by mean-curvature as defined classically by partial differential equations and differential geometry (as in [H1]). However, if K is compact, then the boundary of Ft(K) will necessarily become singular at some finite time. Our goal is to show that the singular sets are necessarily quite small. This we do provided the initial set K is compact and mean-convex in the sense that Ft(K) ⊂ interior(K) for all t > 0. In case M = ∂K is a smooth hypersurface, we have the following equivalent characterization of mean-convexity: K is mean-convex if and only if the mean-curvature of M with respect to the inward unit normal is everywhere non-negative. Given a compact set K, let K be the region in spacetime swept out by the Ft(K): K = {(x, t) ∈ R ×R : t ≥ 0, x ∈ Ft(K)}. (∗) A point X = (x, t) in the boundary of K is called a regular point if (1) X has a neighborhood in which K is a smooth manifold-with-boundary, and (2) the tangent plane to ∂K at X is not horizontal (i.e., is not R × [0]). Note that if X = (x, t) is a regular point, then in a neighborhood of x, Ft(K) is a smooth manifold-with-boundary in R. A point X = (x, t) in ∂K with t > 0 that is not a regular point is called a singular point.