bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbonaceous aerosols contributed by traffic and solid fuel burning at a polluted rural site in Northwestern England
Authors: Liu D. , Allan J. , Corris B. , Flynn M. , Andrews E. , Ogren J. , Beswick K. , Bower K. , Burgess R. , Choularton T. , Dorsey J. , Morgan W. , Williams P. I. , Coe H.
Published: February 2011

Abstract. The experiment presented in this paper was conducted at the Holme Moss site, which is located in the southern Pennines region in Northwestern England during November–December 2006. The strong southwesterly wind during the experimental period, which enhanced the transport of urban pollutants from the conurbations of Greater Manchester and Liverpool, in addition to the seasonally increased nearby residential heating activities, made this site a receptor for pollutants from a range of sources. A factor analysis is applied to the mass spectra of organic matter (OM) measured by the Aerodyne Aerosol Mass Spectrometer (AMS) to attribute the pollutant sources. Besides the oxygenated organic aerosol (OOA), this site was found to contain a considerable fraction of primary organic aerosols (POA, mass fraction 50–70% within total mass of OM). The POA sources are attributed to be traffic emission and solid fuel burning, which are identified as hydrocarbon-like organic aerosol (HOA) and solid fuel organic aerosol (SFOA) respectively. There were strongly combined emissions of black carbon (BC) particles from both sources. The refractory BC component (rBC) was characterized by a single particle soot photometer. This site began to be influenced during the late morning by fresh traffic emissions, whereas solid fuel burning became dominant from late afternoon until night. A covariance analysis of rBC and POA was used to derive source specific emission factors of 1.61 μgHOA/μgrBC and 1.96 μgHOA/μgrBC. The absorbing properties of aerosols were characterized at multiple wavelengths (λ), and a stronger spectral dependence of absorption was observed when this site was significantly influenced by solid fuel burning. The rBC was estimated to contribute 3–16% of submicron aerosol mass. The single scattering albedo at λ = 700 nm (SSA700 nm) was significantly anti-correlated with the rBC mass fraction, but also associated with the BC mixing state. The BC incorporation/removal process therefore may play a role in modulating the radiative properties of aerosols at the site under the influence of fresh sources. Given that traffic and residential combustion of solid fuels are significant contributors of carbonaceous aerosols over Europe, these results provide important source-specific information on modeling the anthropogenic carbonaceous aerosols.
High-resolution wave number spectrum using multi-point measurements in space – the Multi-point Signal Resonator (MSR) technique
Authors: Narita Y. , Glassmeier K.-H. , Motschmann U.
Published: February 2011

Abstract. A new analysis method is presented that provides a high-resolution power spectrum in a broad wave number domain based on multi-point measurements. The analysis technique is referred to as the Multi-point Signal Resonator (MSR) and it benefits from Capon's minimum variance method for obtaining the proper power spectral density of the signal as well as the MUSIC algorithm (Multiple Signal Classification) for considerably reducing the noise part in the spectrum. The mathematical foundation of the analysis method is presented and it is applied to synthetic data as well as Cluster observations of the interplanetary magnetic field. Using the MSR technique for Cluster data we find a wave in the solar wind propagating parallel to the mean magnetic field with relatively small amplitude, which is not identified by the Capon spectrum. The Cluster data analysis shows the potential of the MSR technique for studying waves and turbulence using multi-point measurements.
Temperature variability at Dürres Maar, Germany during the migration period and at high medieval times, inferred from stable carbon isotopes of Sphagnum cellulose
Authors: Moschen R. , Kühl N. , Peters S. , Vos H. , Lücke A.
Published: February 2011

Abstract. This paper presents a high resolution reconstruction of local growing season temperature (GST) anomalies at Dürres Maar, Germany, spanning the last two millennia. The GST anomalies were derived from a stable carbon isotope time series of cellulose chemically extracted from Sphagnum leaves (δ13Ccellulose) separated from a kettle-hole peat deposit of several metres thickness. The temperature reconstruction is based on the Sphagnum δ13Ccellulose /temperature dependency observed in calibration studies. Reconstructed GST anomalies show considerable centennial and decadal scale variability. A cold and presumably also wet phase with below-average temperature is reconstructed between the 4th and 7th century AD which is in accordance with the so called European Migration Period marking the transition from the Late Roman Period to the Early Middle Ages. At High Medieval Times above-average temperatures are obvious followed by a temperature decrease. On the contrary, a pronounced Late Roman Climate Optimum, often described as similar warm or even warmer as medieval times, could not be detected. The temperature signal of the Little Ice Age (LIA) is not preserved in Dürres Maar due to considerable peat cutting that takes place in the first half of the 19th century. The local GST anomalies show a remarkable agreement to northern hemispheric temperature reconstructions based on tree-ring data sets and are also in accordance with climate reconstructions on the basis of lake sediments, glacier advances and retreats, and historical data sets. Most notably, e.g. during the Early Middle Ages and at High Medieval Times, temperatures were not low or high in general. Rather high frequency temperature variability with multiple narrow intervals of below- and above-average temperatures at maximum lasting a few decades are reconstructed. Especially the agreements between our estimated GST anomalies and the NH temperature reconstructions derived from tree-ring chronologies indicate the great potential of Sphagnum leaves δ13Ccellulose time series from peat deposits for palaeoclimate research. This is particularly the case, given that a quantitative δ13Ccellulose/temperature relationship has been found for several Sphagnum species. Although the time resolution of Sphagnum δ13Ccellulose data sets certainly wouldn't reach the annual resolution of tree-ring data, reconstructions of past temperature variability on the basis of this proxy hold one particular advantage: due to often relatively high peat accumulation rates, especially in kettle-hole bogs accumulated on temperate latitudes over periods of up to several millennia, they allow extending temperature reconstructions based on tree-ring series into the past to enhance our knowledge of natural climate variability during the Holocene.
Tracking climate variability in the western Mediterranean during the Late Holocene: a multiproxy approach
Authors: Nieto-Moreno V. , Martínez-Ruiz F. , Giralt S. , Jiménez-Espejo F. , Gallego-Torres D. , Rodrigo-Gámiz M. , García-Orellana J. , Ortega-Huertas M. , de Lange G. J.
Published: February 2011

Abstract. Climate variability in the western Mediterranean is reconstructed for the last 4000 yr using marine sediments recovered in the west Algerian-Balearic basin, near the Alboran basin. Fluctuations in chemical and mineralogical sediment composition as well as grain size distribution are linked to fluvial-eolian oscillations, changes in redox conditions and paleocurrent intensity. Multivariate analyses allowed us to characterize three main groups of geochemical and mineralogical proxies determining the sedimentary record of this region. These three statistical groups were applied to reconstruct paleoclimate conditions at high resolution during the Late Holocene. An increase in fluvial-derived elements (Rb/Al, Ba/Al, REE/Al, Si/Al, Ti/Al, Mg/Al and K/Al ratios), finer grain size, slower flows and oxygen-poor bottom waters – as suggested by sortable silt (10–63 μm), clays (< 2 μm) and redox-sensitive elements (V/Al, Cr/Al, Ni/Al and Zn/Al ratios) – depict the Roman Humid Period (RHP) and the Little Ice Age (LIA), while drier environmental conditions are recognized during the Late Bronze Age-Iron Age (LBA-IA) and the Medieval Warm Period (MWP). Although no Ba excess was registered, other paleoproductivity indicators (total organic carbon content, Br/Al ratio, and organometallic ligands such as U and Cu) display the highest values during the RHP, this period exhibiting by far the most intense productivity of the last 4000 yr. These marine sediments evidence oscillations that support the link of the westernmost Mediterranean climate with the North Atlantic coupled ocean-atmosphere climatic system, pointing to solar irradiance and the North Atlantic Oscillation (NAO) variability as the main driving mechanisms behind natural climate variability over decadal to centennial time-scales for the last 4000 yr.
First level seismic microzonation map of Chennai city – a GIS approach
Authors: Ganapathy G. P.
Published: February 2011

Abstract. Chennai city is the fourth largest metropolis in India, is the focus of economic, social and cultural development and it is the capital of the State of Tamil Nadu. The city has a multi-dimensional growth in development of its infrastructures and population. The area of Chennai has experienced moderate earthquakes in the historical past. Also the Bureau of Indian Standard upgraded the seismic status of Chennai from Low Seismic Hazard (Zone II) to Moderate Seismic Hazard (Zone III)–(BIS: 1893 (2001)). In this connection, a first level seismic microzonation map of Chennai city has been produced with a GIS platform using the themes, viz, Peak Ground Acceleration (PGA), Shear wave velocity at 3 m, Geology, Ground water fluctuation and bed rock depth. The near potential seismic sources were identified from the remote-sensing study and seismo-tectonic details from published literatures. The peak ground acceleration for these seismic sources were estimated based on the attenuation relationship and the maximum PGA for Chennai is 0.176 g. The groundwater fluctuation of the city varies from 0–4 m below ground level. The depth to bedrock configuration shows trough and ridges in the bedrock topography all over the city. The seismic microzonation analysis involved grid datasets (the discrete datasets from different themes were converted to grids) to compute the final seismic hazard grid through integration and weightage analysis of the source themes. The Chennai city has been classified into three broad zones, viz, High, Moderate and Low Seismic Hazard. The High seismic Hazard concentrated in a few places in the western central part of the city. The moderate hazard areas are oriented in NW-SE direction in the Western part. The southern and eastern part will have low seismic hazard. The result of the study may be used as first-hand information in selecting the appropriate earthquake resistant features in designing the forthcoming new buildings against seismic ground motion of the city.
Credibility-Driven Entrepreneurship
Authors: Rehme Jakob , Svensson Peter
Published: February 2011

This article investigates how external stakeholders influence the first sale of technology-based business-to-business start-up companies. The authors combine entrepreneurship theory with marketing theory to describe the marketing and selling activities of start-ups and how new ventures reach key milestones. The study shows how two start-ups, an e-business firm and a new product development firm, acquired their first customers. The analysis provides a picture of how a network of the firms' founders, board members and owners contributed to their first sales. It also highlights the importance of sales activities, relationships and industrial knowledge. The paper examines the importance of external stakeholders' relative positions in the web of relationships and assesses how relevant these are in affecting outcomes and speed to market. The authors conclude that the first sale follows a time line with three important phases of activities involving credibility, closing and operations. They find that credibility is best obtained through establishing relationships.
Two Case Reports of Biliary Tract Injuries during Laparoscopic Cholecystectomy
Authors: Romano O. , Romano C. , Cerbone D. , Sperlongano P. , Caserta L. , Frega N. , Cimmino G. , D'Agostino A. , Addeo R.
Published: February 2011

Background and Study Aims. Biliary tract injuries (BTI) represent the most serious and potentially life-threatening complication of cholecystectomy occurring also during laparoscopic approaches. Patients and Methods. We describe and discuss two different cases of BTI occurring during laparoscopic cholecystectomy (LC). Results. Two patients developed BTI during LC and one evidenced the complication during the LC itself and was treated during the same LC in real time. The other patient evidenced BTI only after the primary intervention and was successfully reoperated in laparotomy after 10 days from the LC. Conclusions. The factors that predispose to the occurrence of BTI during cholecystectomy and the cautions to be used to prevent BTI are discussed.
Localized, Targeted, and Sustained siRNA Delivery
Authors: Krebs Melissa D. , Alsberg Eben
Published: February 2011

Short interfering RNA (siRNA) functions directly in the cytoplasm, where it is assembled into an RNA‐induced silencing complex (RISC). The localized delivery of siRNA to a specific site in vivo is highly challenging. There are many disease states in which a systemic effect of RNAi may be desirable; some examples include non‐localized cancers, HIV, neurodegenerative diseases, respiratory viruses, and heart and vascular disease. In this Concept, we will focus on the localized delivery of siRNA to a target site using various delivery modalities. In certain tissues, such as the eye, central nervous system and lung, it has been demonstrated that a simple injection of naked siRNA will silence gene expression specifically in that tissue. To achieve local gene silencing in other tissues, a variety of approaches have been pursued to help stabilize the siRNA and facilitate uptake; they include chemical modification of the siRNA or complexation within liposomes or polymers to form nanoparticles. Recently, the use of macroscopic biomaterial scaffolds for siRNA delivery has been reported, and although there is still significant work to be done in this area to optimize the delivery systems, it is an important area of research that offers the potential for having great impact on the field of siRNA delivery.
Exploiting σ/π Coordination Isomerism to Prepare Homologous Organoalkali Metal (Li, Na, K) Monomers with Identical Ligand Sets
Authors: Davidson Matthew G. , Garcia‐Vivo Daniel , Kennedy Alan R. , Mulvey Robert E. , Robertson Stuart D.
Published: February 2011

Tetraamine Me6TREN has been used as a scaffold support to provide coordinative saturation in the complexes PhCH2M⋅Me6TREN (M=Li, Na, K). The Li derivative displays a LiC σ interaction with a pyramidalized CH2 both in the solid state and in solution, and represents the first example of η4 coordination of Me6TREN to lithium. In the sodium derivative, the metal cation slips slightly towards the delocalized π electrons whilst maintaining a partial σ interaction with the CH2 group. For the potassium case, coordinative saturation successfully yields the first monomeric benzylpotassium complex, in which the anion binds to the metal cation exclusively through its delocalized π system resulting in a planar CH2 group.
Heat transfer from column wall to bed in spouted fluidized and packed systems
Authors: Klassen J. , Gishler P. E.
Published: February 2011

Heat transfer data have been obtained for heat flowing from a steam jacketed column to a packed, fluidized and spouted bed. The data for packed and fluidized beds are compared with generalized correlations previously proposed. In the case of spouted beds, the heat transfer coefficient increases sharply at the onset of spouting and passes through a maximum as the gas velocity is increased. The maximum heat transfer coefficient is from 25–75% lower for a spouted bed than for a fluidized bed under similar flow conditions. Rice, wheat and Ottawa sand were used as bed materials.
Relative volatility and enthalpy data for the systems C4 hydrocarbons‐acetone‐water developed from vapor‐liquid equilibria
Authors: Ewaischyna J. E. , Ambridge C.
Published: February 2011

Extractive distillation is widely used in separating C4 hydrocarbons. A typical extractive solvent for such a separation is an acetone‐water mixture. Correct design and selection of optimum operating conditions for extractive distillation towers are ensured by a knowledge of the vapor‐liquid equilibria involved.

Pseudo‐binary systems of each of the C4 hydrocarbons, n‐butane, isobutane, butene‐1, and cis‐butene‐2, and acetone‐water solvent were investigated at temperatures of 100°, 150°, and 200°F., at water concentrations of 5, 11, and 17 wt. %, (C4 hydrocarbon‐free) and at hydrocarbon concentrations up to 28 mole %. The results were interpreted as activity coefficients, and showed good consistency. The binary Margules three‐suffix and van Laar two‐suffix equations correlate the measured activity coefficients adequately as a function of concentration.

Dependence of activity coefficients on temperature was used to evaluate the differential heats of solution of the hydrocarbons in the acetone‐water solvent. The results were also used to derive partial liquid enthalpy‐concentration curves.

Ternary Margules three‐suffix and van Laar two‐suffix equations gave a satisfactory correlation of activity coefficients for pseudo‐ternary systems. The ternary Margules equations were used to calculate relative volatilities, which are presented graphically as functions of temperature and composition.
The preparation of a crystalline high explosive of controlled particle size by precipitation with water from acetone solution
Authors: Pennie A. M.
Published: February 2011

The preparation of fine RDX of controlled particle size has been studied and a satisfactory continuous process has been developed. One of the main features of the process is the use of an impinging jet mixing head which obviates many of the variables encountered in previous methods of preparation.
Air agitation and pachuca tanks
Authors: Lamont A. G. W.
Published: February 2011

An expression for the energy transferred from air bubbling through the contents of a tank is developed as a function of the fluid depth in the tank, the specific gravity of the tank contents, the vapor pressure of the solution, atmospheric pressure, and the volume of air used. The variation of the energy transfer with height from the bottom of the tank is also developed.

It is shown that a portion of the energy transferred is used up in small‐scale turbulence and eddy effects, and the remainder is available for generation of a circulation pattern in the contents of the tank.

The information developed is used to determine the pulp circulation pattern in pachuca tanks of various design. The functions fulfilled by pachuca tanks are discussed, and the considerations affecting a choice of tank described.
Mixing studies on a perforated distillation plate
Authors: Johnson A. I. , Marangozis J.
Published: February 2011

In establishing a relationship between the plate efficiency and point efficiency for perforated plates, splashing of the liquid was considered as an entirely new mechanism for the mixing of the liquid phase in the direction of the flow. Actual splashing measurements were reported and correlated here, under different conditions of flow rates, weir height, kinematic viscosity of the liquid and some aspects of tray geometry.

Plate efficiencies for the desorption of ammonia by air were reported for a perforated plate 36 inches long and 3 inches wide. Concentration gradients across the plate were also measured for the ammonia desorption case and for backward distribution of sodium chloride by splashing. These concentration gradients have been related to the splashing measurements.
High purity oxygen for steel making
Authors: Hugill J. T.
Published: February 2011

Recent developments in the manufacture of steel require the use of large quantities of high purity oxygen. To supply this demand new air separation plants have had to be designed and built which are capable of producing oxygen of large tonnage quantities at a minimum purity of 99.5%. This paper will describe in detail the 100 ton/day oxygen units built for Dominion Foundries and Steel Company, at Hamilton, two of which are now in operation. The process flowsheet and the reasons for adopting it is explained. Some of the problems encountered in the choice of certain specialized pieces of equipment are considered. Details of flow, pressure and temperatures are presented for normal operating conditions as well as operating control, methods, and measurement. The paper is illustrated with pictures of the equipment and the assembled plant.
Recent developments in the manufacture of chlorine dioxide
Authors: Rapson W. Howard
Published: February 2011

Fundamental studies on the kinetics of formation of chlorine dioxide have led to an hypothesis concerning the mechanism of the reactions involved. This has lead to improvements in the manufacture of this important bleaching and oxidizing agent. Older processes have been made more efficient and some new ones have been developed.

A new process, patented by the author and assigned to Electric Reduction Co. of Canada Limited in Canada, and to Hooker Chemical Corporation in the United States, employing sodium chlorate, sodium chloride and sulphuric acid as raw materials, is outlined. Recent improvements in the Mathieson, Solvay and Day‐Kesting processes are reviewed, as well as the new Columbia‐Southern modifications of the Persson process.

Trends in absorption tower design, in materials of construction and in bleaching with chlorine dioxide are briefly indicated.
Liquid‐solid separation factors in hydrometallurgical leach circuit design
Authors: Emmett R. C. , Dahlstrom D. A.
Published: February 2011

Practically all hydrometallurgical processes involve leaching of solids to dissolve valuable constituents. This usually is followed by a liquid‐solids separation before producing the final product. The liquid‐solids separation step requires careful investigation because:

Soluble values must be recovered to a very high degree for economic purposes.

Final liquor volume must be minimized to reduce capital and operating costs of later steps.

Usually large amounts of gangue solids are associated with the digested pulp requiring care in minimizing wash volumes.

The colloidal solids are strongly dispersed by retention times and pH conditions in leaching. This necessitates flocculation investigations to achieve desired results.

Operation must be dependable under severe conditions of pH, abrasion, fast settling solids, temperature, etc. Equipment must have flexibility to allow efficient operation under even abnormal fluctuations.

An appreciable percentage of initial investment is required for this portion of the plant.

The two common liquid‐solids separation methods —countercurrent decantation and filtration with cake washing, are discussed. Investigation and correlation procedures for prediction of full scale results and design requirements are stressed. Emphasis is given to the influence of particle size distribution, temperature, pH, flocculation, repulping, solids concentration, and filter cake permeability.
The effect of the less viscous liquid in the laminar flow of two immiscible liquids
Authors: Russell T. W. F. , Charles M. E.
Published: February 2011

Instances are cited in which the pressure gradient in an oil pipe line has been reduced by the injection of water into the pipeline. A general mathematical analysis is presented for two immiscible liquids flowing (1) in two layers between wide parallel plates, and (2) concentrically in a circular pipe. This will form a basis for the further study of oil‐water systems. Equations are derived relating the volumetric flow rates and the viscosities of the liquids with the pressure gradient. The conditions for which minimum pressure gradients and minimum power requirements occur were determined and these minimum values have been compared with known values for a pipeline flowing full with only a single liquid. The factors by which the pressure gradient and power requirement can be reduced are very large. For example, for an oil of viscosity 1,000 cp. flowing concentrically with water, the reduction factor is approximately 500. The pressure gradient reduction factors reported in the literature are compared with those predicted by theory, and conclusions are drawn regarding the position of the water phase.
Use of lead in chemical and metallurgical plant construction
Authors: Turner A. , Wellington J. R. , Williams L.
Published: February 2011

The use of lead in the chemical and metallurgical operations at Trail, B.C. is described.

A wide variety of corrosive environments are encountered, including phosphoric and sulphuric acids, sulphur dioxide, fluorides, and ammonium sulphate. It is found that except in the presence of fluorine compounds, 6% antimonial lead is more resistant to corrosion than is soft lead.

The mechanical properties of lead are reviewed with particular reference to its high specific gravity, low mechanical strength, creep and fatigue properties. Principles of plant design to give adequate support, to provide for thermal expansion and contraction, and to minimize the effects of creep and fatigue are enunciated, and illustrated by proven designs that have given long periods of satisfactory service.
The pyrolysis of a heavy crude oil in a fluidized bed
Authors: Madgwick G. G. , Amberg C. H. , Peterson W. S.
Published: February 2011

The pyrolysis of a heavy high sulphur crude oil in an inert fluidized bed at temperatures between 550 and 800°C. has resulted in the production of an olefin rich gas and a liquid product containing increasing amounts of aromatic material with increasing temperature.

Analysis of the process gas has shown that for average reactor residence times of more than one second, equilibrium is approximated for the system ethane‐ethylene‐hydrogen. There is considerable scatter in the data for the analogous system propane‐propylene‐hydrogen but for most conditions a significant deviation from equilibrium exists.

The sulphur compounds in the light oil were of thiophenic character. The ratio of 2‐ to 3‐methylthiophene in the toluene fractions was examined.
The effects of shape and reynolds number on drag in the motion of a freely oriented body in an infinite fluid
Authors: Becker H. A.
Published: February 2011

The drag on freely oriented bodies in motion relative to an infinite fluid is related to the Reynolds number, ReS, by the formula

K = 24ReS + CIRes2

where Res = DsuOρ/μ is formed from the diameter, Ds, of a sphere with the same surface area as the body, and K = 8ρFD/πμ2 is defined as the drag number. The inertial drag coefficient, Cl, is related to shape, orientation, and the Reynolds number. At Reynolds numbers above 2000 the relation is expressed by the formula,

Cl = 2.53 − 0.283e2Ψ

where Ψ, the surface sphericity, is the ratio of the surface area of a sphere with the same volume to the gurface area of the body. Correlations are also developed for predicting Cl at Reynolds numbers below 2000.
Sodium hydroxide‐sodium sulphate stripping of uranium from amine extracts
Authors: Bellingham A. I. , Simard R.
Published: February 2011

Batch shake‐out tests on two tertiary amines and one secondary amine to determine the effects of sodium sulphate concentration and pH on the distribution of uranium between 0.1N amine in kerosene and aqueous sodium sulphate solution showed that transfer of uranium from the solvent to the aqueous phase was favored by increasing pH values up to 5.5 and by increasing the aqueous sodium sulphate concentration up to 20% w/v Na2SO4.

Continuous counter‐current stripping of tri‐isooctylamine (TIOA) extracts with 20% w/v Na2SO4 was also carried out in a three‐stage mixer‐settler arrangement in which the pH was controlled by the addition of 10% NaOH to the three stages. Further addition of caustic to the separated aqueous strip solution to raise the pH to 7.0–7.2 yielded a high grade uranium precipitate (88% U3O8). The continuous testing confirmed the results of the shake‐out tests and showed that the procedure gave results comparing favorably with other stripping methods accompanied by a lower overall reagent cost.
Performance of flow reactors at various levels of mixing
Authors: Cholette A. , Blanchet J. , Cloutier Léonce
Published: February 2011

Chemical flow reactors studied include models in which partial mixing and piston flow are present and others which involve partial mixing and short‐circuit. Mixing levels considered extend all the way between the extreme cases of tubular and continuous‐stirred tank reactors. Various orders of reaction are taken into account.

The curves presented, obtained through analytical methods, show either the variation of conversion with mixing level at given values of residence time, or relative residence times for a given conversion. Graphical methods of solution are proposed. They involve, in part, a means of computation whereby the overall conversion for a number of reactors in series is obtained from the individual conversions.

While isothermal conditions only have been considered, more interesting results are expected when other conditions are applicable, whether isothermal or not.
Evaporation of stationary droplets in high temperature surroundings
Authors: Hoffman T. W. , Gauvin W. H.
Published: February 2011

An experimental study of the rate of evaporation of stationary droplets of water, methanol, cumene, pentane and benzene was carried out in an electrically‐heated 9‐inch stainless steel sphere. The gaseous environment consisted of the superheated vapor of the liquid under investigation and, in all cases, the wall and gas temperatures were the same. Drop diameters ranged from 0.4 to 1.4 mm., and temperatures from 100°C. to 550°C.

The evaporation rate of stationary droplets in high temperature surroundings does not appear to be governed by the rate of heat transfer by natural convection, since no dependency of the Nusselt Number on the Grashof Number was found. Attempts to correlate the results on the basis of Godsave's model (conduction across the boundary layer controlling) or Spalding's modified approach to the latter were equally unsuccessful. The experimental evaporation rates could, however, be very satisfactorily correlated in terms of Spalding's Transfer Number B.

The correlation obtained indicates that the mechanism of the evaporation process is governed by the effect of the evolved vapors on the boundary layer flow.
The horizontal pipeline flow of equal density oil‐water mixtures
Authors: Charles M. E. , Govier G. W. , Hodgson G. W.
Published: February 2011

The horizontal flow of equal density oil‐water mixtures was investigated in a 1‐inch diameter laboratory pipeline. Oils of viscosities 6.29, 16.8 and 65.0 centipoise were used in the experiments. Flow patterns, holdup ratios and pressure gradients were investigated for a range of superficial oil velocity from 0.05 to 3.0 ft./sec. and a range of superficial water velocity from 0.1 to 3.5 ft./sec, with input oil‐water ratios ranging from 0.1 to 10.0.

Similar series of flow patterns were observed for each oil and were found to be largely independent of the oil viscosity. At high oil‐water ratios oil formed the continuous phase and a water‐drops‐in‐oil regime was noted. As the oil‐water ratio was decreased the flow patterns concentric oil‐in‐water, oil‐slugs‐in‐water, oil‐bubbles‐in‐water and oil‐drops‐in‐water in which water was the continuous phase were observed. The most viscous oil did, however, exhibit anomalous behavior at low superficial water velocities and this is attributed to different interfacial properties.

The pressure drops measured indicated that for a given oil flow rate the pressure gradient was reduced to a minimum by the addition of water provided that the oil was not in turbulent flow. Maximum pressure gradient reduction factors varied from 1.7 for the 6.29 centipoise viscosity oil to 10 for the 65.0 centipoise viscosity oil at input oil‐water ratios of 4.5 and 1.0 respectively.
The upward vertical flow of oil‐water mixtures
Authors: Govier G. W. , Sullivan G. A. , Wood R. K.
Published: February 2011

The upward vertical flow of oil‐water mixtures has been investigated in a 37‐ft. length of cellulose acetate butyrate tubing of inside diameter 1.038‐in. Flow pattern, holdup and pressure drop data were obtained for water mixtures with 0.936, 20.1 and 150 centipoise oils at superficial water velocities ranging from 0.10 to 10.0 ft./sec.

The oil‐water mixtures exhibited a behavior similar to that of air‐water mixtures studied previously. The flow patterns observed at constant superficial water velocity with increasing oil‐water ratio were: drops of oil in water, slugs of oil in water, froth, and drops of water in oil. Holdup of the phase forming the continuous medium was observed but to a much lesser extent than with the air‐water system. Curves of pressure drop versus oil‐water ratio exhibited a minimum, a maximum and a second minimum at low water velocities; a single minimum at intermediate water velocities; and a steady increase at superficial water velocities above about 5 ft./sec.

A friction factor based upon the properties and the superficial velocity of the water is correlated with the superficial velocity of the oil and a Reynolds number based on the properties and superficial velocity of the water. This shows that the pressure drop due to friction and other irreversibilities is essentially independent of the viscosity of the oil except under conditions where the oil is the continuous phase.
Dynamic behavior of a continuous stirred‐tank reactor
Authors: Kermode Richard I. , Stevens William F.
Published: February 2011

Solution of the non‐linear differential equations of a continuous flow stirred‐tank reactor, with a first‐order reacting system, has been accomplished by the use of the analog computer. The three common modes of control have been programmed on the computer and, while controlling temperature or composition by means of the adjustment of cooling water flow rate, the regions of stability have been determined for various values of the controller constants. These results have been compared to those obtained by applying the root‐locus method to the linearized forms of the differential equations previously derived.
Spherical agglomeration of solids in liquid suspension
Authors: Farnand J. R. , Smith H. M. , Puddington I. E.
Published: February 2011

The process of spherical agglomeration provides a method for making rapid and efficient separations of solids from liquid suspensions. Because preferential wetting of the solid surface by a second liquid, which acts as a bridging agent between the particles, is a basic requirement of the operation, a novel method for the separation of multi‐component solids becomes available. The procedure is also useful in the breaking of emulsions through the addition of a finely divided solid, the surface of which is repellent to the continuous phase and wetted by the emulsified phase. The process operates equally well in aqueous or in organic media. A number of illustrative examples are given.
Heat‐transfer to high‐quality steam‐water mixtures flowing in a horizontal rectangular duct
Authors: Davis E. J. , David M. M.
Published: February 2011

Heat transfer and pressure drop were investigated for steam‐water mixtures flowing in an electrically heated horizontal duct of rectangular cross‐section. The investigation was primarily concerned with the region of high vapor fractions and mass flow rates, where two‐phase convention‐controlled heat transfer predominated.

The experimental data were found to be in good agreement with those of other studies in which circular tubes were used. The data in the convection‐controlled region were correlated by equations developed from two flow models, a separated‐annular model and a homogeneous model.

Two phase pressure drop data were correlated satisfactorily by the Lockhart‐Martinelli correlation.
Fluid friction and heat transfer in cylindrical pipes: Relationship between lumped and distributed parameters
Authors: Smith Julian C.
Published: February 2011

Physical phenomena may be described from the “microscopic” point of view, in terms of distributed parameters, or from the “macroscopic” viewpoint, using lumped parameters. Engineering correlations almost always involve lumped parameters. A lumped parameter is equal or proportional to some average value of the corresponding distributed parameter. Like any average quantity it gives no information regarding the form of the distribution. The use of lumped parameters therefore requires some assumptions, expressed or implied, regarding the form of the distribution within the system.

The characteristic lumped parameters used in problems of heat transfer and fluid friction are overall or average fluxes of heat energy or momentum, arbitrarily defined as described in this paper. Common dimensionless groups, such as f, NBe, NSt and others are ratios of these energy or momentum fluxes. Such dimensionless groups, since they are ratios of lumped parameters, are themselves lumped parameters. In their definition, therefore, several assumptions regarding the distributions of velocity and temperature are implicit. When these assumptions are not valid, correction factors such as diffusivity ratios or length‐to‐length ratios are needed to allow for deviations from the distributions used for reference.

Using this approach the form of empirical equations becomes easy to predict. Dimensional analysis is not needed. In addition, this approach suggests that some accepted correlations may contain weaknesses not predicted by other methods.
Mass transfer with and without chemical reaction
Authors: Marangozis J. , Johnson A. I.
Published: February 2011

Rates of dissolution of cast solids in a baffled agitated vessel were obtained for the systems: Benzoic acid‐water, o‐salicylic acid‐water, benzoic acid‐22.5% acqueous glycerol and benzoic acid‐41% aqueous glycerol. A new continuous technique was developed for the measurements, and the data were empirically correlated by the method of least squares with the equation

with a mean deviation of ± 5.8%.

The present data agreed qualitatively with the predictions of the turbulent boundary layer theory.

Reaction factors,kL/kL°, were also measured in the agitated vessels for the systems: Benzoic acid‐aqueous sodium hydroxide solutions, benzoic acid‐aqueous potassium hydroxide solutions, and o‐salicylic acid‐aqueous sodium hydroxide solutions. The data were found to depend strongly on the ratio of the reactant concentrations,CB/CA6, in a manner quantitatively predicted by the boundary layer theory corrected for ion‐diffusion effects.

Reaction factors were also measured in diaphragm‐type diffusion cells for the system benzoic acid‐sodium hydroxide. The results provided quantitative support for the ion‐diffusion theory in a stagnant film.
An analysis of spray evaporation in a high‐temperature environment: I. Radiant heat transfer to clouds of droplets and particles
Authors: Hoffman T. W. , Gauvin W. H.
Published: February 2011

This series of papers presents an analysis of the rate of evaporation of a spray which is injected into a cylindrical column, the walls of which are maintained at a high temperature. The method is an extension of the Hottel‐Cohen analysis of the radiant heat transfer to an absorbing gas of non‐uniform temperature1 and permits the calculation of the magnitude and distribution of the heat flux at the wall.

The present paper discusses the difficulties inherent in the calculation of the absorption of thermal radiation by clouds of particles suspended in an absorbing gas medium. Approximations to the intractable exact solution are made to permit the calculation of the absorption strength of spray from operating conditions and the properties of the atomized liquid.

The various reception factors for the cylindrical system have been accurately determined as a function of the combined absorption strength of spray and medium. The use of these factors in the present system is discussed.
Prefabricated plastic piping
Authors: Nenniger E.
Published: February 2011

This paper describes some procedures used to design and develop prefabricated plastic pipe for a chemical plant installation. Two aspects of this design are: (a) Stresses in mitred elbows; (b) Flange reinforcing. It has been found that the only stress resulting from internal static pressure on a mitred pipe joint is that of pure tension. The most satisfactory method of flange reinforcing involves the use of a steel backing ring. The ring tends to reduce the bending stresses on the flange to a minimum and facilitates the working at higher static pressures.
Problems in direct reduction
Authors: Meissner Herman P.
Published: February 2011

The status of direct reduction processes for iron production is briefly discussed. More extensive commercial plant operation of these processes appears to depend in part on solution to problems of scale‐up. These problems center around the reactors used, which are either rotary kilns, shaft kilns, or fluid bed units. Possible ways of solving these scale‐up problems are discussed.
On optimal adiabatic reactors of combined types
Authors: Aris Rutherford
Published: February 2011

Some fairly general considerations arising out of the work of Cholette and Blanchet on combined stirred tank and tubular reactors are here presented. General analytical and graphical conditions for the optimality of the MT combination are given and it is shown that, save for autocatalytic reactions, the combination is only optimal for sufficiently exothermic reactions. The proportions of the optimal combined reactor can be readily calculated and it is shown that the stirred tank design is always stable. A circumstance under which the TM combination is optimal is also suggested but it is thought to be of rare occurrence.
Studies on fermentation aeration: II. Catalyst effects on sulphite oxidation rates
Authors: Roxburgh J. M.
Published: February 2011

Sulphite oxidation rates using several metal ions as catalyst in four types of contacting equipment have been measured over a considerable range of agitation levels. The data show no simple relation between the various sulphite oxidation rates and the transfer coefficient for oxygen from air to fermentation media.
Laminar heat transfer of power‐law non‐Newtonian fluid—the extension of Graet‐Nusselt problem
Authors: Tien Chi
Published: February 2011

The asymptotic solutions of the classical Graetz‐Nusselt Problem is extended to the case of power‐law non‐Newtonian fluid flowing between parallel plates. Expressions are given for the eigen value, eigen functions and its related expressions, average temperature and Nusselt modulus.
Approximation methods to evaluate the effect of axial dispersion in isothermal flow reactors
Authors: Houghton Gerald
Published: February 2011

Two quasi‐analytical methods are given for the approximate solution of the nonlinear differential equation governing the effect of longitudinal dispersion on the concentration profile in an isothermal flow reactor with reaction orders other than zero or first. The first method converts the nonlinear differential equation and its boundary conditions into a nonlinear integral equation which is solved by iteration, while the second method generates approximate solutions by considering axial dispersion as a perturbation on the reaction kinetics. By using the perturbation method a dimensionless group has been generated that is characteristic of the interaction between axial diffusion and reaction kinetics. It is also demonstrated that an axial dispersion coefficient characteristic of Taylor diffusion can be applied in the presence of a reaction of any order and that the effect of depletion of concentration by chemical reaction is to aid in the reduction of radial concentration gradients.
The dynamics of the expanding vapor bubble in a boiling liquid
Authors: Savic P. , Gosnell J. W.
Published: February 2011

The theory of a constant pressure vapor bubble growing in a liquid with both superheat and sub‐cooling is presented. In the case where the initial temperature profile is purely radial, bubble radius‐time curves and temperature profile near the bubble are calculated. For the case of the hemispherical bubble growing on a plane heater surface with initially plane parallel temperature distribution, it is shown that the problem may be reduced to that of radial temperature profile if the inverse thickness of the superheated layer measured along the radius vector is averaged over the surface of the bubble. It is further shown that in the latter case vaporization is always present at the foot of the bubble, but condensation may occur near the top where the bubble penetrates furthest into the subcooled liquid.
A study of the condensation of binary vapors of miscible liquids: Part I: The equilibrium relations
Authors: Tenn F. G. , Missen R. W.
Published: February 2011

Liquid‐vapor equilibrium data at 750 mm. Hg are given for the four binary systems CH3OH + CH2Cl2, n‐C5H12 + CH2Cl2, n‐C5H12 + CH3OH and n‐C5H12 + n‐C6H14. The second and third of these systems have been shown previously to exhibit the phenomenon of non‐filmwise condensation, and the equilibrium data are used in the following paper to calculate (condensing) film coefficients for the liquid and vapor films. The first three systems are azeotropic, and the compositions and boiling points (at 750 mm. Hg) of the minimum‐boiling azeotropes are given.

Densities have also been measured for the system n‐C5H12 + CH3OH at 25°C. and refractive indices at 25°C. for the other three systems. The calculated volume of mixing for n‐C5H12 + CH3OH is positive at all compositions. A geometrical interpretation of this is discussed in comparison with results previously obtained for solutions of alcohols and carbon tetrachloride.
Viscosity of suspensions of coal in mineral oil
Authors: Moreland C.
Published: February 2011

Viscosity data for slurries of five solid particle systems suspended in a mineral oil are presented for solid concentrations up to 50% by volume. At volume concentrations of less than 30% the results are well represented by the Einstein equation in its fluidity form, the constant varying with the system between 2.65 and 3.15, (as compared with 2.5 in the theoretical equation). At higher concentrations the slurries are non‐Newtonian, and no satisfactory correlation is available in this region, very little complete data for the high concentration region have been published.

Slurry viscosities are greater for smaller particles, and are greater for irregular particles than for spherical particles. Slurry viscosities in regions of high concentration can be considerably reduced by careful selection of particle size distribution.

Pressure gradients measured in an experimental pipeline carrying a suspension of coal in oil in laminar flow could not have been predicted using the viscosities determined in the laboratory.
An economic study of propane propylene splitter operation
Authors: Smy K. G. , Hay J. M.
Published: February 2011

Detailed economic studies were prepared for the distillation of a propane‐propylene mixture to make 99% propylene: (a) low pressure operation with vapor recompression (b) high pressure with water condensation.

The equipment required was calculated for various reflux ratios at both pressures. The relative economics are compared.

These calculations allow a study by inference of the relative cost of the two methods of recovering propylene from a cracked gas stream. One method is to distill the individual components overhead in a series of columns. The alternative is to take a cut of C3's from the main stream and recover the propylene from this cut. It was found that the latter case was the most economic.

In calculating the column requirements various methods were used for estimating the number of trays required. These methods are compared.