Spray Flux Research Articles

The SDS and steel surface interaction behaviour in case of high mass flux spray cooling from very high temperature

The use of additives as a coolant enhances the heat transfer rate as it alters the thermo physical properties of the fluid in the favourable direction of heat transfer. Although the aforesaid technology mitigate the requirements depicted in Time Temperature Transformation diagram; however, the quenching from high temperature, which may lead to a reaction with coolant, deposition and modification of surface morphology has not been addressed in the open literature. Therefore, in the current work, the interaction of coolant with the surface has been tried to disclose in terms of surface reaction, deposition or physical changes leading to variation in morphology. In the current work, AISI 304 steel plates are quenched by water with varied concentration of SDS to mitigate the cooling requirement and by using EDS, XRD and SEM analysis, the surface interaction is revealed. The elemental analysis by EDS and XRD clearly indicate the formation of new compounds resulted from the reaction between hot steel and the coolant. Based on the identified compounds formed on the surface, the possible reactions on the surface due to interaction among the hot surface, water, oxygen and adsorbed SDS are proposed and also validated.

The role of dissolved carbon dioxide in case of high mass flux spray quenching, dropwise and flow boiling on a hot steel plate

In the current work, by altering the vapour bubble formation and their coalescence rate, the Leidenfrost effect is tried to eliminate or minimize by dissolving carbon dioxide in the water spray. The heat transfer analysis indicates that the heat removal rate steps up with the increment in carbon dioxide concentration up to 8 gm/litre soda concentration in water and a further rise in carbon dioxide concentration, quenching rate declines. The droplet impact mapping and the film boiling analysis corroborate the aforesaid results. The evaporation experiment also supports above findings and indicates unalteration of boiling point. The spray cooling result shows 37% enhancement in critical heat flux (CHF from 1.2 MW/m2 to 1.67 MW/m2) at 8 gm/litre soda concentration in water. The comparison of the critical heat flux with the results reported in the literature clearly asserts the suitability of the current methodology for the fast cooling operation.

Experimental study on spray characteristics of pressure-swirl nozzle in China advanced PWR containment

Pressurized Water Reactor (PWR) is the most mature technology for nuclear power plants and nuclear power devices. Spray systems play an essential role in the safety of a PWR. The spray characteristics of the nozzle are of crucial importance for the performance of the spray system. In the present study, a test loop with four rotatable branches was established to obtain spray characteristics data, including flow characteristic, spray cone angle (SCA), spray flux distribution and droplet size spectrum. The effect of inclined angles was taken into consideration when designing and conducting the experiment. A specific type of pressure-swirl nozzle used in China advanced PWR was employed for the study. According to experimental data, variations of pressure drop and the spray angles versus volume flow rate were obtained, and typical curves of spray flux distribution were plotted, and the change in the flux distribution was evident with the change in inclined angle. The flux distribution results were used to build 3D spray flux distribution models together with the spray cone angles tested. The droplet size spectrum was measured by laser diffraction analysis. Typical droplet size distributions were obtained by the relevant software, and the experimental Probability Density Function (PDF) of droplet size was derived and compared with several empirical distributions.

High mass flux spray quenching on an inclined surface: A novel methodology for the attainment of enhanced uniform cooling with unaltered surface morphology in transition boiling regime

The main obligation in the successful implementation of ultra-fast cooling in a manufacturing process are: (1) significant minimization of film boiling effect, (2) achievement of unaltered surface morphology and (3) uniform cooling on the surface of the plate. The literature does not reveal any methodology, which depicts simultaneously enhancement, unaltered surface morphology and uniform cooling. Therefore, in the current work, an attempt has been made to develop an appropriate cooling process depicting all the aforesaid requirements. The cooling on an inclined condition of the plate mitigates the aforesaid requirements. The result reveals that the heat removal rate enhances (CHF from 1.21 MW/m2 to 1.46 MW/m2) due to augmentation of sweeping rate of vapor film from the hot surface as inclination angle increases from 0° to 30°. Further increase of the inclination from 30° to 60° decreases the cooling rate due to reduction of droplet velocity, residence time and the replacement rate of the vapor and liquid layers. The optimum inclination of the plate to achieve the maximum average surface heat flux is 30°. In addition, the temperature distribution on the surface and across the thickness of the heat treated plate confirms uniform cooling. The SEM image and the EDS of the current heat treated metal is compared with the SEM images and EDS data of the metals cooled by potential coolants such as surfactant added water, NaCl added water and MgSO4 added water and the comparison clearly asserts unaltered surface morphology for the current case. The variation of the hardness on the surface and across the thickness clearly asserts the excellent shock absorbing characteristics.

Characterization of the boiling width on metal quenching with spray cooling

ABSTRACTA hot aluminum alloy AA6082 and nickel disc of 560°C and 850°C was cooled by water spray of various spray flux under different condition of experiment. Temperature history was recorded with use of an infrared camera. During the quenching process, it was observed that the area with no apparent boiling and the outer annular region with vigorous liquid boiling have formed the boiling region. The width of the boiling region is essential as the maximum heat flux point is within the boiling region. Boiling width increases with initial temperature but decreases with water subcooling, spray flux and salinity.

An experimental study on the spray characteristics of pressure nozzle in a fluid bed granulation

ABSTRACTThe particles with a narrow size distribution are proper products in a fluid bed granulation and coating. As well, the process efficiency is one of the most important parameters, and the wall deposition of sprayed liquid reduces it. The modality of spray volume distribution is a key parameter in the definition of particle size distribution and process efficiency. This work is done in two steps: In the first step, an experimental study on spray characteristics including spray flux distribution, spray cone angle, and discharge coefficient is conducted. Based on the experimental data, the curves of liquid volume flux versus nozzle pressure and height are obtained. The results indicate that the flux distribution changes significantly with even small pressure and height changes. In the second step, the granulation process is carried out in a semi-industrial conical fluid bed, and the particles size distribution curves and the deposited mass on the bed wall are obtained. The results show that the precise determination of the spray flux distribution is an appropriate way to predict the well-advised nozzle pressure/height in order to achieve the narrow particle size distribution and high efficiency of the process.

Upward and downward facing high mass flux spray cooling with additives: A novel technique to enhance the heat removal rate at high initial surface temperature

The objective of the current work is to enhance the spray cooling by changing the orientation of the nozzle with different additives (acetone, methanol, ethanol, benzene, n-hexane, tween 20 and salt) in water. The experiments are carried out by upward, downward and both upward and downward facing sprays. The optimization result depicts that the spray produced by upward facing spray gives higher heat flux than the downward facing spray and also cooling by both the upward and downward facing spray simultaneously produces better result than the individual. Further experiments with both upward and downward facing spray by using different coolants reveal that in case of cooling by ethanol (500 ppm) + water mixture, the maximum enhancement of surface heat flux (~2.57 MW/m2) and cooling rate (204 °C/s) is observed. However, the minimum surface heat flux is achieved in case of methanol (100 ppm) + water due to higher contact angle (710) among all the considered coolants.

Analytical Model for Describing Experimental Results on Parameters Influencing Heat Transfer in Film Boiling with Spray Quenching

ABSTRACTAn analytically solvable mathematical model is developed to estimate heat transfer quantities in the film boiling region of metal quenching with water sprays. The model is based on the hydrodynamic of a single droplet which is separated from the metal by a vapor film. The temperature profile within the droplet is calculated as semi-infinite body because of the short contact time. It is validated with own experimental results and those from the literature. The influence of size and velocity of the droplet, spray flux, surface temperature, temperature of the cooling water and the salinity level are discussed. The droplet size and velocity play a less significant influence on the heat transfer. The heat transfer coefficient is found to increase linearly with the spray flux. The heat flux is proportional to the difference of boiling and water temperature. With the model it is shown, that even for the high impingement densities the droplet covered area is very small.

Dynamic Leidenfrost temperature increase of impacting droplets containing high-alcohol surfactant

Methods to avoid the dynamic Leidenfrost effect are of great importance for high heat flux spray cooling which needs an efficient contact of liquid and superheated surface. In this paper, a novel method of increasing dynamic Leidenfrost temperature is proposed through addition of high-alcohol surfactant (HAS). Effects of 1-Octanol and 2-ethyl-hexanol surfactants on dynamic Leidenfrost temperature and spreading dynamic of droplets impacting on superheated surface were investigated for the first time using high-speed photography. Empirical correlations of dynamic Leidenfrost temperature and maximum spreading factor were obtained based on our experimental data. A possible explanation for the dynamic Leidenfrost temperature increase caused by HAS was proposed based on bubble bursting and bubble coalescence. The results show that dynamic Leidenfrost temperature is significantly increased by addition of HAS because of surface tension reduction. The empirical correlations of dynamic Leidenfrost temperature and maximum spreading factor show good agreement with maximum error of 5% and 10% respectively. These empirical correlations could provide reference value for the future research.

Impacts of the size distributions and protein contents of the native wheat powders in their structuration behaviour by wet agglomeration

The control of the wet agglomeration processes of powders depends on the contribution of the characteristics of the native powders. The objective of this work is to specifically investigate the contribution of the size distribution (d50 and span) and composition (the protein contents) of the native particles, on the dimensional and structural characteristics of the wet agglomerates. Different fractions of native semolina with contrasted size properties (d50 and span) and protein content are used as raw materials. The wet granulation is conducted using a low shear granulator and liquid spraying condition at constant dimensionless spray flux. The structure properties are evaluated by the distribution of the measured values of the size, water content and compactness. We observed specific effects of the span and the median diameter of native powders on the size distributions of the wet agglomerates. Using small native particles (d50 < 250 μm) improves the homogeneity of the size distributions. Using slightly dispersed native particles (span < 1.0) leads to a better uniformity on the size distributions. Using semolina with high protein content could lead to a narrow size distribution by limiting the process of fragmentation and the formation of fragments in the bed. We showed that the mechanisms involved in the agglomeration process are similar whatever the size distribution and the protein content of the native powders.

Enhancement of heat removal rate of high mass flux spray cooling by sea water

The main obligation in achieving high cooling rates in case of spray cooling at high surface temperature is the occurrence of film boiling phenomenon. Although the high mass flux spray reduces the film boiling affect, still, the heat transfer rate is not significant and hence, this process needs to be enhanced. In the absence of any information on the heat transfer augmentation technique, the present work deals with the enhancement of high mass flux spray cooling at very high initial plate temperature by using sea water. The sea water spray cooling process increases the heat removal rate by creating high heat transfer area for the droplet evaporation and by reducing the vapour pressure of vapour film on the hot plate. The cooling ability of the sea water spray is compared with the coolants (salt added water, surfactant added water and surfactant and salt added water) which partially depict the properties of sea water. For the experimental investigation, spray cooling was conducted at 900°C initial surface temperature on a 6mm thick AISI 304 steel plate (100×100mm) by using sea water and also aforesaid coolants at different concentrations. The surface heat flux and surface temperature have been predicted using the solution of the Inverse Heat Conduction Problem (IHCP). For the understanding of heat transfer mechanism, the properties of coolants (contact angle, thermal conductivity, density, specific heat and mass diffusivity) at different concentrations and spray behaviour (droplet diameter, spray pressure, droplet velocity and spray impingement density) at different flow rates were measured. The physical properties of the coolant reveal that the contact angle decreases with the increasing salt concentration up to 0.1M and further increment in salt concentration enhances the contact angle. From the thermal properties of the coolant, it is observed that thermal diffusivity in sea water is higher than salt added water. The sea water spray cooling asserts that the heat removal rate increases with the increasing percentage of sea water in the mixture of seawater and pure water due to the salt deposition on the hot surface. However, the achieved heat removal rate is lower than that of salt added water due to the comparatively less amount of salt deposition in case of sea water spray. Furthermore, the combined effect of the salt deposition and lowering of vapour pressure in vapour film phenomena produce better heat removal rate than the pure water and surfactant and salt added water. In comparison between sea water and surfactant added water spray cooling, the former produces higher heat removal rate because of the dominance of salt deposition phenomenon over the lowering of contact angle property. In case of sea water spray, the achieved critical heat flux (1.55MW/m2) is 1.3 times that of pure water (1.2MW/m2); moreover, the enhanced critical heat flux is obtained at 170°C higher surface temperatures. In addition to the above, the enhancement by NaCl added water spray is almost 1.6 times that of pure water. Due to the above mentioned favourable conditions for the fast cooling, the maximum cooling rates of 115°C/s and 135°C/s are achieved with sea water and NaCl added water sprays, respectively.

Development and evaluation of a dimensionless mechanistic pan coating model for the prediction of coated tablet appearance

A mathematical, mechanistic tablet film-coating model has been developed for pharmaceutical pan coating systems based on the mechanisms of atomisation, tablet bed movement and droplet drying with the main purpose of predicting tablet appearance quality. Two dimensionless quantities were used to characterise the product properties and operating parameters: the dimensionless Spray Flux (relating to area coverage of the spray droplets) and the Niblett Number (relating to the time available for drying of coating droplets). The Niblett Number is the ratio between the time a droplet needs to dry under given thermodynamic conditions and the time available for the droplet while on the surface of the tablet bed. The time available for drying on the tablet bed surface is critical for appearance quality. These two dimensionless quantities were used to select process parameters for a set of 22 coating experiments, performed over a wide range of multivariate process parameters. The dimensionless Regime Map created can be used to visualise the effect of interacting process parameters on overall tablet appearance quality and defects such as picking and logo bridging.

High mass flux spray cooling with additives of low specific heat and surface tension: A novel process to enhance the heat removal rate

High mass flux spray cooling is a good replacement of conventional cooling methods such as jet cooling and laminar cooling in metallurgical industries. However, the cooling rates obtained in spray cooling are still not sufficient for the production of high tensile strength and moderate hardenability steel. The challenging task in the conventional spray cooling is the elimination of film boiling phenomenon. The solution to such difficulties is the use of high mass flux spray which generates high momentum droplets that penetrates the vapour film and almost excludes the film boiling affect. Along with the aforesaid advantage, the high mass flux spray also creates low residence time that leads to incomplete evaporation and as a consequence, the obtained heat transfer rate is not significant. Hence, the heat removal rate needs to be further enhanced. This can be achieved by increasing the heat transfer area and lowering the sensible heating time. So, in the current work, coolants of low specific heat and surface tension are prepared by separately mixing water with benzene, acetone and n-hexane in different combinations to see the effects of specific heat and surface tension on heat transfer rate. The substrate used was a square AISI 304 steel plate (100×100×6mm). The surface temperatures and heat fluxes were calculated by using INTEMP software. Before experimentation, the mass flux and nozzle to plate distance were optimised. The result shows significant augmentation of heat removal rate with an increment in critical heat flux of 40, 30 and 20% with acetone, n-hexane and benzene, respectively. Moreover, mathematical correlations are developed using Design Expert software to determine the heat transfer coefficient at different properties of coolants.

Enhancement of heat transfer rate of high mass flux spray cooling by ethanol-water and ethanol-tween20-water solution at very high initial surface temperature

•Obligations in achieving high cooling rates by spray cooling are overcome.•Heat removal is enhanced by spray cooling with coolants-ethanol and tween20 in water.•Achieved CHF with Tween 20-ethanol-water mixture is 1.6 times higher than pure water.•Maximum obtained cooling rate is 141°C/s in case of ethanol-water-Tween 20 mixture.

Influence of a Young Pinus radiata Canopy on Aerial Spray Drift

Abstract. An experiment was undertaken to test the hypothesis that AGDISP, a mechanistic model that simulates the landing position of droplets aerially released for pesticide application, overestimates downwind airborne spray concentrations by not accounting for the turbulence generated within the canopy sublayer. AGDISP is used by pesticide regulators in many parts of the world to quantify exposure from aerial pesticide spraying as part of an assessment of risks to public health and the environment. Using a novel design, airborne spray drift was measured in a 3.2 m high radiata pine plantation, 65 m downwind from the aerial spray flight line, using a small circular sampling array. The spray sampling array consisted of a central 10 m high mast plus a set of 16 secondary masts distributed evenly around a circle with a radius of 5 m from the central mast. All spray applications were made with a Bell Jet Ranger using a spray mix of water plus a fluorescent tracer and a droplet spectrum with a volume median diameter of 101 µm. A single treatment comprised six passes along the flight line, and there were 28 replications. Airborne spray was sampled with both rotorods and artificial foliage placed at four heights on the central mast, ranging from approximately half canopy height to 3 times canopy height. The secondary towers sampled airborne spray using the same collectors placed at just above canopy height and at half canopy height. Other measurements included leaf area distribution, prevailing meteorological conditions, and turbulence using sonic anemometers. Backscatter LiDAR was used in an attempt to quantify the height and density of the spray cloud in the vicinity of the central mast. Rotorod and artificial foliage deposition values were highly correlated, giving confidence in the sampling approach. Neither wind speed nor release height had a significant effect on airborne spray flux in the 0 to 10 m zone, but results were complicated by a spurious negative correlation between wind speed and spray release height. The lack of dependence of deposition on wind speed in this experiment is surprising but is explained both by the variance in the data as well as the physics of small droplet movement in the atmosphere. At the individual sample level, measurements of airborne spray using either rotorods or artificial foliage were poorly correlated with AGDISP predictions. However, when data were averaged across replications, there was a very strong correlation between measurements and AGDISP data, even though in absolute terms, and as hypothesized, AGDISP significantly overpredicted the quantity of airborne spray. As indicated from a comparison with measured deposition, the backscatter LiDAR appeared effective in describing the spray cloud profile, and it suggested a total spray cloud profile that was more complex than the AGDISP model prediction. Keywords: Aerial application, AGDISP, Canopy deposition, Pesticides, Spray drift.

Normalized Spray Flux Distribution in Impinging Atomization

Normalized Spray Flux Distribution in Impinging Atomization

Role of water temperature in case of high mass flux spray cooling of a hot AISI 304 steel plate at different initial surface temperatures

ABSTRACTIn case of spray evaporative cooling, the heat transfer rate is controlled by various factors such as droplet renewal rate, Leidenfrost effect, and the rate of heat extraction by each droplet. In the current work, in case of high mass flux spray cooling (~55 kg/m2s), the heat extraction rate is tried to enhance by increasing the water temperature. Furthermore, from different initial surface temperatures (300°C–800°C), cooling experiments were conducted at various water temperatures (10°C–50°C). The surface temperatures and heat fluxes are calculated using an inverse heat conduction software (INTEMP). The result reveals that with the increasing water temperature, the heat removal rate rises in both transition and nucleate boiling regimes due to the increment of latent heat extraction time during the residence period of the water droplet on the hot plate. The maximum percentage in the enhancement of initial heat flux, average heat flux (AHF), and critical heat flux (CHF) are achieved in the nucleate boiling regime (<600°C); however, the increment in the transition boiling regime is also significant.Abbreviations: , hfg: Latent heat of vaporisation of water, J/kg; , Cp: Specific heat of water, J/kg oC; : Specific heat of water vapour, J/kg oC; : Average impingement density, kg/m2s; : Local impingement density at ith location, kg/m2s; : Surface temperature of plate, saturation temperature of water and injection temperature of water, °C; : Velocity of the droplet, m/s; : Density of water vapour, kg/m3; , : Density of water, kg/m3; ∆T: Temperature difference between the plate and the water droplet, °C; AHF, : Average surface heat flux, MW/m2; CHF,: Critical surface heat flux, MW/m2; DAQ: Data acquisition system; Dd: Diameter of droplet, µm; Fw: Flow rate of water, m3/s; g: Acceleration due to gravity, m/s2; IHF: Initial surface heat flux, MW/m2; k: Thermal conductivity of steel plate, W/m°C; m: Mass of water droplet, kg; OES: Optical Emission Spectrophotometer; P: Spray pressure, MPa; q: Heat flux, MW/m2; S1, S2 and S3: Surface heat flux zones; t: Time, s; T: Transient temperature of steel plate, °C; T1, T2, T3, and T4: Water temperatures, °C; TC1, TC2, and TC3: Thermocouple locations; We: Weber number; x, X, y, Y, Z: Distance along the length, breadth, and thickness of the plate, mm; z: Characteristic length, m; λ: Vapour film wavelength, m; ρ: Density of steel plate, kg/m3; σ: Surface tension of water, N/m; : Wetting front length, m; : Number of locations at which local impingement densities were measured; : Cooling efficiency

Modelled and observed sea-spray icing in Arctic-Norwegian waters

Hazardous marine icing is a major concern for ships operating in Arctic waters during freezing conditions. Sea spray generated by the interaction between a ship and ocean waves is the most important water source in these dangerous icing events. Although there exist several data sets with observations of ice accretion in conjunction with meteorological and oceanographic parameters, these data sets often have shortcomings and only a few are obtained in Arctic-Norwegian waters. In this study, icing rates from a large coast-guard vessel type, the KV Nordkapp class, are used for verification of a newly proposed Marine-Icing Model for the Norwegian COast Guard (MINCOG). Ship observations, NOrwegian ReAnalysis 10km data (NORA10), and wave data based on empirical statistical relationships between wind and waves are all applied in MINCOG and the results are compared. The model includes two different empirically-derived formulations of spray flux. It is found that in general the best results for different verification scores are obtained by using a combination of observed atmosphere and ocean-wave parameters from the ships, and wave period and direction from NORA10, regardless of the spray-flux formulation applied. Furthermore, the results illuminate that wave parameters derived from formulas based on empirical relationships between the local wind speed and significant wave height and wave period, compared to those obtained from observations or NORA10, considerably worsen icing-rate predictions in Arctic-Norwegian waters when applied in MINCOG.

Scale-up of a high shear wet granulation process using a nucleation regime map approach

Scale-up of the high shear wet granulation (HSWG) process is considered a challenge because HSWG is complex and influenced by numerous factors, including equipment, formulation, and process variables. For a system of microcrystalline cellulose and water, HSWG experiments at three scales (1, 2, and 4L working vessel) were conducted with a granulator. Scale-up was implemented on the basis of a nucleation regime map approach. To keep dimensionless spray flux and drop penetration time constant, water addition time at three processing scales were 300, 442, and 700s, respectively. The other process parameters were kept unchanged. Granule size distributions were plotted and compared, and scanning electron microscopy was used to analyze granule surface morphology. Physical characterization was undertaken using a modified SeDeM method. At nearly all scales, granule yield was greater than 85% and all the cosine values were larger than 0.89. At the same experiment points, granules at all scales had similar surface morphology and similar physical characteristics. The results demonstrate that a rational scaling-up of the HSWG process is feasible using a regime map approach.

In Memoriam: Edgar L. Andreas, 1946-2015

On a day early last autumn, Ed Andreas went out, as was his wont, for a run from his home in Lebanon, New Hampshire. While on this run, Ed, a contributor to this volume and a collaborator and friend of many of us in the air-sea exchange community, suffered a cardiac event, from which he succumbed on 30 September 2015.Mention of Ed Andreas will immediately bring to many readers’ minds his protracted effort to incrementally improve the existing parameterizations of the sea surface spray flux (e.g., Andreas et al. 1995; Andreas 1998; Andreas 2001; Andreas et al. 2015) and his recent efforts to combine this modeling with concepts from atmospheric chemistry to assess the potential significance of spray-mediated air-sea gas flux (Andreas et al., this volume). Since 2007 Ed worked on these topics from his home, which served as his outpost of NorthWest Research Associates. But it should be noted that many of his earlier papers dealt with the Arctic marine boundary layer, and sea-air fluxes at high latitudes (e.g., Andreas et al. 1979; Makshtas et al. 1986), reflecting his almost 30-year long tenure (1978-2006) at the U.S. Army's Cold Regions Research and Engineering Laboratory of the U.S. Army Corps of Engineers, located just down the road from Lebanon, in Hanover, New Hampshire.Having been born in Sterling, Illinois, Ed went off to nearby Knox College for his B.S. in Physics, and then on to Michigan State University for an M.S. in Physics, before deserting the Midwest for Corvallis, where he earned his Ph.D. in Physical Oceanography at Oregon State University in 1977. While Ed certainly became an active member of our global scientific community, he never lost his Midwestern virtues. He could write well, and received numerous awards for his technical communication, but he was often refreshingly candid in speech. Ed would on occasion provide honest “unvarnished” critiques of his and his collaborators’ efforts, but he did not hesitate to praise others’ efforts in print. Ed was a principled person, and this was manifest in his professional dealings with others. Working on a manuscript with Ed was always, as it should be, an ultimately enlightening intellectual exercise.His approach to any task combined both the rigor of the physicist with the practicality of an engineer, and as a result of his efficient nature, he has left our air-sea interaction community with a trove of no less than 140 valuable scientific publications, with others yet to appear.Ed Andreas was a Fellow of the American Meteorological Society and of the Royal Meteorological Society (UK). He was recipient of the Antarctica Service Medal, and of numerous performance awards from the Cold Regions Research and Engineering Laboratory.This brief tribute just touches upon Ed Andreas as a scientist. But Ed was a truly multi-faceted individual, as is apparent to any reader of the posthumous biographical sketch that appeared in his local newspaper (Jurgens 2015), which you may want to access. We would like to acknowledge with gratitude the biographical materials we received from Ed's immediate family, and from his former associates at NorthWest Research Associates, Inc. in Redmond, Washington.