Three different methods are compared to estimate the instantaneous peak flow (IPF) from the corresponding maximum daily flow (MDF), as the daily data are more often available at gauges of interest and often with longer recording periods. In the first approach, simple linear regression is applied to calculate IPF from MDF values using probability weighted moments and quantile values. In the second method, the use of stepwise multiple linear regression analysis allows to identify the most important catchment descriptors of the study basin. The resulting equation can be applied to transfer MDF into IPF. With the third method, the temporal scaling properties of annual maximum flow series are investigated based on the hypothesis of piece wise simple scaling combined with the generalized extreme value distribution. The scaling formulas developed from three 15 min stations in the Aller-Leine river basin of Germany are transferred to all daily stations to estimate the IPF. The method based on stepwise multiple linear regression gives the best results compared with the other two methods. The simple regression method is the easiest to apply given sufficient peak flow data, while the scaling method is the most efficient method with regard to data use.
Laboratory test report - the effect of scale formation on heat transfer coils
BackgroundEVAPCO, Inc. recently introduced new Evaporative Condensers and Closed Circuit Coolers which utilize extended surface coils. For decades extended “fin” surfaces have been used on heat transfer coils, often referred to as “finned coils” primarily in an effort to increase dry capacity. However, in the past the fin material was limited to carbon steel tubes with a “round profile” prior to hot dip galvanizing. In most cases, the fin material was applied to a few rows of...
Tetrapak, Alfa Laval, Westfalia, Cream separators and Sialex®Ring - Case Study
Tipperary Co-operative, use Sialex®Ring to help control "Scaling" on Plate Heat and Shell and Tube heat exchangers on their " hot water circuits". A further area suitable to benefit from Sialex® is in the Cream separators. These devices are prone to "Scale" build up on flushing jets. Cleaning requires did-assembly and cleaning. This can occur several times during a year. Platetek Engineering proposed installing Sialex®Ring onto the water "feed lines" to the cream separators (Alfa Laval, westphalia)....
Case Study PHE (Plate Heat Exchanger) test results in hard water region
Industry, hotels, commercial buildings even private homes in "Hard" water areas are at a disadvantage due to "Scale" formation on devices, particularly those attached to "Hot" water circuits. A PHE (Plate Heat Exchanger) with a known "Scaling" problem is selected for testing. The attached case study demonstrates how with an "Open" mind, even those sceptical of our products capabilities, do not dispute the achieved results.
Maximizing membrane life: lessons learned from a three year study on performance recovery
Abstract Reverse Osmosis (RO) membranes are susceptible to several different types of foulants and scales. Common foulants observed in RO systems are organics, metals, clays and colloidal material. Common scales that are observed are carbonate, phosphate, sulfate and silica. Onsite cleaning is the norm to remove these foulants and scales but sometimes a desire for cleaning optimization or a requirement for process troubleshooting leads operators to undertake a more detailed investigation. Therefore, one option...
Advancements in Scaling Calculations and an in depth look at Antiscalant dosing for stressed waters ...
Abstract Over the past few decades the Reverse Osmosis (RO) industry has observed an increase in applications in challenging waters. Water sources that were never considered suitable for RO are now commonplace, including municipal waste streams, industrial waste, and even mining waste. Furthermore, regulatory restrictions, environmental obligations, solid waste expenses, and water supply shortages have forced the industry to push system recoveries to higher and higher limits. Many systems are now running at...