Experimental study of temperature stratification in an integrated collector-storage solar water heater with two horizontal tanks

The effect of tank-interconnection geometry on temperature stratification in an integrated collector-storage solar water (ICSSW) heater with two horizontal cylindrical tanks has been studied. The tanks were parallel to each other, and separated horizontally and vertically, with the lower tank fitted directly below a glass cover, and half of the upper tank insulated. In addition, a truncated parabolic concentrator was fitted below the tanks, with its focal line along the axis of the upper tank. The heater was tested outdoors with the two tanks connected in parallel (P), and S1-and S2-series configurations, with and without hot water draw-off. Water temperature was monitored during solar collection and hot water draw-offs. For the heat charging process, it was found that only the lower tank exhibited temperature stratification in the P-and S1-tank modes of operation. There was satisfactory temperature stratification in both tanks in the S2-tank configuration. For the hot water draining process, the P-tank configuration exhibited some degree of stratification in both tanks. A significant loss of stratification was observed in the lower tank, with the upper tank exhibiting practical stratification, when the system was operated in the S1-tank mode. The S2-tank interconnection maintained a satisfactory degree of temperature stratification in both tanks. So, the S2-tank mode of operation was most effective in promoting practical temperature stratification in both tanks during solar collection and hot water draw-offs. Other results are presented and discussed in this paper

Vortex motion phase separator for zero gravity liquid transfer

A vortex motion phase separator is disclosed for transferring a liquid in a zero gravity environment while at the same time separating the liquid from vapors found within either the sender or the receiving tanks. The separator comprises a rigid sender tank having a circular cross-section and rigid receiver tank having a circular cross-section. A plurality of ducts connects the sender tank and the receiver tank. Disposed within the ducts connecting the receiver tank and the sender tank is a pump and a plurality of valves. The pump is powered by an electric motor and is adapted to draw either the liquid or a mixture of the liquid and the vapor from the sender tank. Initially, the mixture drawn from the sender tank is directed through a portion of the ductwork and back into the sender tank at a tangent to the inside surface of the sender tank, thereby creating a swirling vortex of the mixture within the sender tank. As the pumping action increases, the speed of the swirling action within the sender tank increases creating an increase in the centrifugal force operating on the mixture. The effect of the centrifugal force is to cause the heavier liquid to migrate to the inside surface of the sender tank and to separate from the vapor. When this separation reaches a predetermined degree, control means is activated to direct the liquid conveyed by the pump directly into the receiver tank. At the same time, the vapor within the receiver tank is directed from the receiver tank back into the sender tank. This flow continues until substantially all of the liquid is transferred from the sender tank to the receiver tank

STUDI PERENCANAAN SISTEM DISTRIBUSI AIR BERSIH PADA GEDUNG DITRESKRIMSUS KEPOLISIAN DAERAH JAWA TIMUR

The plumbing system is an inseparable part of a high-rise building. The plumbing system is used for various purposes such as providing clean water and distributing sewage and waste water. To meet the needs of clean water in the Ditreskrimsus Building of the East Java Regional Police, requires planning a clean water distribution system, a 5-storey building with the type and number of plumbing equipment required clean water amounting to 58.996 m3 / day. The capacity of the lower water reservoir (Ground Water Tank) used is 8 m3, the upper water tank (Roof Tank) is used as a water reservoir of 7 m3. Based on the results of the calculation, a transfer pump is used to drain water from the lower water tank (Ground Water Tank) to the upper water tank (Roof Tank) with a flowing capacity of 16.2 m3 / hour and a transfer pump head of 7-54 m. for clean water distribution, you can use the thrust of the potential height of the water from the upper reservoir to the sanitary equipment on each floor. The pump used is the Ebara 50x40 FSHA brand

Fitting Heterogeneous Lanchester Models on the Kursk Campaign

The battle of Kursk between Soviet and German is known to be the biggest tank battle in the history. The present paper uses the tank and artillery data from the Kursk database for fitting both forms of homogeneous and heterogeneous Lanchester model. Under homogeneous form the Soviet (or German) tank casualty is attributed to only the German(or Soviet) tank engagement. For heterogeneous form the tank casualty is attributed to both tank and artillery engagements. A set of differential equations using both forms have been developed, and the commonly used least square estimation is compared with maximum likelihood estimation for attrition rates and exponent coefficients. For validating the models, different goodness-of-fit measures like R2, sum-of-square-residuals (SSR), root-mean-square error (RMSE), Kolmogorov-Smirnov (KS) and chi-square statistics are used for comparison. Numerical results suggest the model is statistically more accurate when each day of the battle is considered as a mini-battle. The distribution patterns of the SSR and likelihood values with varying parameters are represented using contour plots and 3D surfaces

Liquidity Effects of Changes in a Pan-European Stock Index

Adding or deleting a security to or from an index can influence the share price considerably. A possible explanation that has been brought forward in the literature is the liquidity hypothesis according to which an increase in liquidity after an addition is responsible for the observed rise in value. In the following paper, we examine liquidity effects on securities that have been added to or deleted from the pan- European index STOXX 50 between 1998 and 2003, using bid-ask spreads as indicators for liquidity. While there is a medium term price effect, bid-ask spreads do not change significantly due to the index addition or deletion. Regression analysis shows that the explanatory power of bid- ask spreads for the observed price effect is negligible. As a consequence of our empirical findings, the liquidity hypothesis has to be rejected for the STOXX 50. This result, however, does not appear particularly surprising, as the STOXX 50 is composed of already highly liquid securities whose trading liquidity appears not to depend on membership in an international index. A possible explanation for the rejection of the liquidity hypothesis is that the applicability of the liquidity hypothesis hinges on the liquidity class of the stocks concerned before being added. Marginal increases of liquidity due to an index addition might decline with larger initial liquidity of the stocks added. Subsequent studies could focus on the particular shape of this 'liquidity curve' of stocks.Pan-European stock index, index effect, STOXX, liquidity, price effect

Self-powered mixer for pressurized containers

Mechanical stirrer, installed entirely within tank, is powered by turbine driven by discharge flow of fluid. Contents of tank are automatically mixed whenever fluid in tank is discharged. Magnetic coupling eliminates need for shaft seal, particularly in high-pressure tanks

Three stage rocket vehicle with parallel staging

A three stage rocket vehicle has a large forward propellant tank and a small aft propellant tank axially aligned. Secured to the rear end of the aft propellant tank is an engine mount structure carrying rocket engines. Offset and secured to the propellant tanks is a payload structure. The propellants from the large forward tank are fed into the aft propellant tank. This arrangement enables the vehicle to parallel stage its use of engines and components and results in significant payload capability. The design and components fully utilize existing space shuttle elements and tooling

Acid Polishing of Lead Crystal Glass

The industrial partner manufactures high quality lead crystal glassware. The cutting of decorative features in the glass damages the surface and the cuts are optically opaque; to restore transparency, the glass is polished in a solution of hydrofluoric (HF) and sulphuric acid (H2 SO4 .) The polishing process comprises three stages: 1. immersion in a polishing tank containing acid; 2. rinsing in a tank containing water; and 3. settlement of the solid reaction products in a settlement tank. The manufacturer hopes to optimise its polishing process to • minimise the health/environmental impact of the process; • maximise throughput; • maintain the sharpness of the cut edges while still polishing to an acceptable level of transparency. The study group was asked to focus on modelling three aspects of the process: • the chemical reactions involved in the etching at the glass-acid solution interface; • the removal of reaction products in the settlement tank; • flow within the polishing tank