bluuebunny/crossref_metadata_2025 huggingface dataset:
CAN SELF‐CONTROL CHANGE SUBSTANTIALLY OVER TIME? RETHINKING THE RELATIONSHIP BETWEEN SELF‐ AND SOCIAL CONTROL*
Authors: NA CHONGMIN , PATERNOSTER RAYMOND
Published: March 2012

The primary goals of this study were to test the long‐term stability thesis of Gottfredson and Hirschi's (1990) general theory of crime and to examine the relationship between self‐control and social control over time. The data come from a field experiment where the “treatment” consisted of an intentional effort to improve the childrearing behaviors of a sample of caregivers whose children were at high risk of criminal behavior. Caregivers in the control condition were given no such training. The intervention occurred when all subjects were in the first grade (mean age: 6.2 years old), and we have measurements on self‐control and the social control/bond for each subject from grades 6 to 11 (mean ages: 12 to 17 years old). Both a hierarchical linear model and a second‐order latent growth model identified meaningful differences in the growth pattern of self‐control among individuals in the pooled sample and a difference in the growth parameters for self‐control and the social control/bond over time between the treatment and control groups. Both findings are inconsistent with Gottfredson and Hirschi's stability of self‐control hypothesis. The same patterns persisted when different analytic techniques and model specifications were applied, which suggests that the results are not an artifact of measurement error, model specification, or statistical methods. Structural equation modeling using the panel design of the data was better able to disentangle the long‐term relationship between self‐ and social control—a relationship that was found to be more dynamic than previously hypothesized.
Carbohydrate and preprandial insulin determination in diabetes: a review
Authors: MORGAN Amanda C.
Published: February 2012

Aim:  This review evaluates the various methods of determining preprandial insulin doses in relation to carbohydrate intake.

Methods:  A search was conducted in the Medline and ProQuest databases. Intervention or discussion papers involving insulin requirements and carbohydrate estimation, or the glycaemic response to food were reviewed.

Results:  The amount of carbohydrate and the glycaemic index both significantly affect glycaemic response and insulin requirements. Most carbohydrate estimation methods improve glycaemic control and some reduce hypoglycaemia. Carbohydrate ‘counting’ involves more complex processes, has a higher patient burden than qualitative methods and may lead to negative food choices.

Conclusions:  No one method of carbohydrate estimation is better at predicting preprandial insulin requirements. Qualitative methods may be preferred due to the ease of execution and adherence issues.
China's Approach to Rebalancing: A Conceptual and Policy Framework
Authors: Deer Luke , Song Ligang
Published: February 2012

This article seeks to develop a conceptual and policy framework for understanding China's role in the global economic imbalances. China's contribution to these imbalances via recurrent trade and financial surpluses corresponds with a phase of deepening structural risks to China's economic growth and development. These structural challenges include: the composition of growth resulting from China's dynamic internal transformation, China's trade orientation, the trajectory of resource use and CO2 emissions, welfare problems relating to distribution and international constraints. This article develops a conceptual framework for examining the relationship between the processes of long‐run structural transformation in China, its economic imbalances, and the role of institutional reform in dealing with these structural challenges. As such, economic policy should extend beyond short‐term macro management to pursue an institutional reform agenda to facilitate broader structural change to mitigate constraints to future growth and to improve economic welfare.
Rebalancing China's Economic Growth: Some Insights from Japan's Experience
Authors: Fukumoto Tomoyuki , Muto Ichiro
Published: February 2012

One of the greatest challenges China faces is reshaping its heavily investment‐driven mode of economic growth. By investigating how the rebalancing of Japan's economic growth mode was realized in the 1970s, we indicate that it is essential in rebalancing to correct the distortions in factor cost (labor cost and capital cost) in a harmonious way. In addition, we refer to Japan's experience to indicate that rebalancing of domestic growth does not necessarily lead to external rebalancing.
Poverty Reduction in China: The Contribution of Popularizing Primary Education
Authors: Song Yang
Published: February 2012

Using the instrumental variable model and the regression discontinuity approach, this paper explores how access to primary education affects the Chinese labor market and helps people to escape poverty. Several important findings are obtained. The popularization of primary education has significantly reduced poverty in China, especially in urban areas. In contrast, the Compulsory Education Law has not been well implemented for older children in rural areas. In addition, the labor market premium for completing primary education is much larger in urban areas than in rural areas. Poor rural school quality might explain this rural–urban disparity. Effort needs to be made to further reduce poverty by ensuring adequate financial resources for primary education in poor areas and improving school quality in rural China.
Snowmelt Runoff and Water Yield Along Elevation and Temperature Gradients in California’s Southern Sierra Nevada1
Authors: Hunsaker Carolyn T. , Whitaker Thomas W. , Bales Roger C.
Published: February 2012

Hunsaker, Carolyn T., Thomas W. Whitaker, and Roger C. Bales, 2012. Snowmelt Runoff and Water Yield Along Elevation and Temperature Gradients in California’s Southern Sierra Nevada. Journal of the American Water Resources Association (JAWRA) 48(4): 667‐678. DOI: 10.1111/j.1752‐1688.2012.00641.x

Abstract:  Differences in hydrologic response across the rain‐snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment elevation over the range 1,800‐2,400 m. Higher‐elevation catchments have lower vegetation density, shallow soils with rapid permeability, and a shorter growing season when compared with those at lower elevations. Average annual temperatures ranged from 6.8°C at 2,400 m to 8.6 at 1,950 m elevation, with annual precipitation being 75‐95% snow at the highest elevations vs. 20‐50% at the lowest. Peak discharge lagged peak snow accumulation on the order of 60 days at the higher elevations and 20 to 30 days at the lower elevations. Snowmelt dominated the daily streamflow cycle over a period of about 30 days in higher elevation catchments, followed by a 15‐day transition to evapotranspiration dominating the daily streamflow cycle. Discharge from lower elevation catchments was rainfall dominated in spring, with the transition to evapotranspiration dominance being less distinct. Climate warming that results in a longer growing season and a shift from snow to rain would result in earlier runoff and a lower runoff ratio.
Proteasome inhibition and ROS generation by 4‐nerolidylcatechol induces melanoma cell death
Authors: Brohem Carla A. , Massaro Renato R. , Tiago Manoela , Marinho Camila E. , Jasiulionis Miriam G. , de Almeida Rebeca L. , Rivelli Diogo P. , Albuquerque Renata C. , de Oliveira Tiago F. , de Melo Loureiro Ana P. , Okada Sabrina , Soengas María S. , de Moraes Barros Silvia B. , Maria‐Engler Silvya S.
Published: February 2012

Induction of apoptotic cell death in response to chemotherapy and other external stimuli has proved extremely difficult in melanoma, leading to tumor progression, metastasis formation and resistance to therapy. A promising approach for cancer chemotherapy is the inhibition of proteasomal activity, as the half‐life of the majority of cellular proteins is under proteasomal control and inhibitors have been shown to induce cell death programs in a wide variety of tumor cell types. 4‐Nerolidylcatechol (4‐NC) is a potent antioxidant whose cytotoxic potential has already been demonstrated in melanoma tumor cell lines. Furthermore, 4‐NC was able to induce the accumulation of ubiquitinated proteins, including classic targets of this process such as Mcl‐1. As shown for other proteasomal inhibitors in melanoma, the cytotoxic action of 4‐NC is time‐dependent upon the pro‐apoptotic protein Noxa, which is able to bind and neutralize Mcl‐1. We demonstrate the role of 4‐NC as a potent inducer of ROS and p53. The use of an artificial skin model containing melanoma also provided evidence that 4‐NC prevented melanoma proliferation in a 3D model that more closely resembles normal human skin.
The enigmatic ginger Alpinia melichroa rediscovered in southeast Sulawesi
Authors: Sharp Nicky J. , Newman Mark F. , Santika Yessi , Gufrin  , Poulsen Axel Dalberg
Published: February 2012

Recent collections from Sulawesi allow an investigation of Amomum subgenus Botryamomum K. Schum. and its three species, Amomum chrysogynia K. Schum., A. echinosphaera K. Schum., and A. melichroum K. Schum. It is concluded that this subgenus contains a single species, Amomum melichroum K. Schum. Amomum subgenus Botryamomum and Amomum melichroum are lectotypified and Schumann's classification of them as Alpinia melichroa (K. Schum.) K. Schum. in Alpinia sect. Botryamomum (K. Schum.) K. Schum. is accepted. An amplified description including flowers and fruits is provided. Alpinia melichroa is narrowly distributed in southeastern Sulawesi; a conservation assessment is given.
Structural alterations of faecal and mucosa‐associated bacterial communities in irritable bowel syndrome
Authors: Durbán Ana , Abellán Juan J. , Jiménez‐Hernández Nuria , Salgado Patricia , Ponce Marta , Ponce Julio , Garrigues Vicente , Latorre Amparo , Moya Andrés
Published: March 2012

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder in western countries. Previous studies on IBS, mostly based on faecal samples, suggest alterations in the intestinal microbiota. However, no consensus has been reached regarding the association between specific bacteria and IBS. We explore the alterations of intestinal bacterial communities in IBS using massive sequencing of amplified 16S rRNA genes. Mucosal biopsies of the ascending and descending colon and faeces from 16 IBS patients and 9 healthy controls were analysed. Strong inter‐individual variation was observed in the composition of the bacterial communities in both patients and controls. These communities showed less diversity in IBS cases. There were larger differences in the microbiota composition between biopsies and faeces than between patients and controls. We found a few over‐represented and under‐represented taxa in IBS cases with respect to controls. The detected alterations varied by site, with no changes being consistent across sample types.
Oral focal mucinosis in an adolescent: a case report
Authors: Lee JG , Allen G , Moore L , Gue S
Published: February 2012

Oral focal mucinosis (OFM) is an uncommon soft tissue lesion of unknown aetiology. Clinically, it is most commonly found on the gingiva and presents as a painless, sessile or pedunculated mass that is the same colour as surrounding mucosa. Histologically, it is characterized by focal myxoid degeneration of connective tissue. OFM occurs predominantly in adults during the fourth and fifth decade of life, although it has been reported infrequently in children and adolescents. Diagnosis relies on histological analysis and treatment involves complete surgical excision. Recurrence is unreported. This case report describes the clinical and histological presentation and subsequent management of OFM in an adolescent female patient.
EXPLANATIONIST REBUTTALS (COHERENTISM DEFENDED AGAIN)
Authors: LYCAN WILLIAM G.
Published: March 2012

abstract

An explanatory coherence theory of justification is sketched and then defended against a number of recent objections: conservatism and relativism; wild and crazy beliefs; reliability; warranted necessary falsehoods; basing; distant, unknown coherences; Sosa's “self‐ and present‐abstracts”; and Bayesian impossibility results.
COHERENCE: THE PRICE IS RIGHT
Authors: THAGARD PAUL
Published: March 2012

abstract

This article is a response to Elijah Millgram's argument that my characterization of coherence as constraint satisfaction is inadequate for philosophical purposes because it provides no guarantee that the most coherent theory available will be true. I argue that the constraint satisfaction account of coherence satisfies the philosophical, computational, and psychological prerequisites for the development of epistemological and ethical theories.
A method for detecting molecular transport within the cerebral ventricles of live zebrafish (Danio rerio) larvae
Authors: Turner Maxwell H. , Ullmann Jeremy F.P. , Kay Alan R.
Published: February 2012

Key points 

The cerebral ventricles of the vertebrate brain form a series of interconnected chambers through which cerebrospinal fluid flows serving an important role in brain homeostasis and development.

We introduce the larval zebrafish brain as a model for studying the physiology of the cerebral ventricles.

The three dimensional form of the zebrafish ventricles was characterized by in vivo confocal microscopy and found to be similar to that of mammals.

To follow the movement of molecules within ventricles we have a developed a technique using the uncaging of a fluorescent molecule.

Zebrafish larvae provide a tractable model for studying ventricles and the movement of chemicals across the blood–brain barrier.
In vivo patch‐clamp recording from locus coeruleus neurones in the rat brainstem
Authors: Sugiyama Daisuke , Hur Sung Won , Pickering Anthony E. , Kase Daisuke , Kim Sang Jeong , Kawamata Mikito , Imoto Keiji , Furue Hidemasa
Published: February 2012

Abstract  Locus coeruleus (LC) neurones extend noradrenergic projections throughout the neuroaxis and are involved in homeostatic functions such as pain modulation, arousal and cardio‐respiratory control. To address the cellular mechanisms underlying pain modulation we have developed a patch‐clamp recording technique from LC neurones in anaesthetized rats. These recordings showed LC discharge in vivo to be driven by both spontaneous membrane potential oscillations and CNQX‐sensitive EPSCs opposed by bicuculine‐sensitive IPSCs. Hindlimb pinch evoked a biphasic action potential response underpinned by a slow monophasic excitatory current. This approach allows detailed characterisation of the synaptic and integrative mechanisms of LC responses to naturalistic stimulation.
Film Boiling Heat Transfer From an Oscillating Sphere
Authors: Rhea L. G. , Nevins R. G.
Published: February 2012

An experimental investigation has been undertaken to determine the effect of oscillation of the heat transfer surface on turbulent film boiling heat transfer. A transient technique was used to calculate the heat flux from copper spheres of 1 in., 3/4 in., and 1/2 in. dia. In all tests, saturated liquid nitrogen at atmospheric pressure was used as the boiling fluid. The data obtained were found to be in good agreement with published theory at zero frequency. The range of frequencies studied was from zero to approximately 12 cps at peak-to-peak amplitudes of 2 in. and 1 in., i.e., at amplitude-to-diameter ratios of 1.00, 1.34, 2.00, 2.67, and 4.00. It was determined that oscillation of the heat transfer surface considerably increases the heat flux for a given temperature difference over that for natural convection film boiling. The results were correlated with a maximum deviation of +35, −17 percent. The correlation equation Nu=0.14gd3ρvf(ρl−ρvf)μvf2(Pr)vfhfgCpvfΔT+0.5ag+X2F2gd1/3 showed that the Nusselt number was proportional to the vibrational Fronde number to the 2/3 power. Tests were conducted with spheres having a corroded surface, a glass-bead-peened surface and a Teflon-coated surface. The results show that the turbulent film boiling from an oscillating sphere is independent of the condition of the heat transfer surface over the range of frequencies and amplitudes tested.
Transient Heat and Mass Transfer to a Translating Droplet
Authors: Chao B. T.
Published: February 2012

An analysis is made for the transient response behavior of thermal or concentration boundary layers of a fluid sphere moving at constant velocity with internal circulation in another fluid of large extent under the condition of large Reynolds and Peclet numbers. The disturbance is initiated by a step change in temperature or solute concentration of either the continuous or disperse region fluids. The governing energy or mass conservation equations are solved using similarity transformations. The result shows that the growth of the boundary layers is independent of the fluid properties but is governed by a single parameter; namely, the product of the translating speed and time divided by the droplet radius. For all practical purposes, the transients will die out when the value of that parameter attains unity.
Combined Free and Forced Convection Heat Transfer From a Heated Tube to a Transverse Air Stream
Authors: Sharma G. K. , Sukhatme S. P.
Published: February 2012

Heat transfer by combined free and forced convection from a heated tube to a transverse air stream has been experimentally studied over a wide range of Grashof and Reynolds numbers. The data obtained have been correlated with Gr/Re2.5 as the correlating parameter. Criteria for transition from free convection to combined convection and from combined convection to forced convection have also been obtained.
Forced Convection in Concentric-Sphere Heat Exchangers
Authors: Rundell H. A. , Ward E. G. , Cox J. E.
Published: February 2012

The first experimental investigation of forced convection of a fluid through the annulus formed by two concentric spheres was performed. The fluid enters and leaves the annulus through diametrically opposed openings in the outer sphere. The inner sphere serves as a constant-temperature heat source. Four sphere-size combinations were tested. The flow patterns in the annulus were established by flow visualization techniques; characteristic photographic results are presented. Energy considerations include heat transfer rates, inner-sphere surface temperatures, and temperature traverses of the coolant fluid. An empirical relation correlates the heat transfer data.
Turbulent Natural Convection from a Vertical Plane Surface
Authors: Cheesewright R.
Published: February 2012

The paper reports the results of an experimental investigation which was intended to clarify the present uncertain position with regard to the distributions of mean temperature and mean velocity in a turbulent natural-convection boundary layer. Data reported for the turbulent boundary layer for Grashof numbers between 1010 and 1011 include local heat transfer coefficients as well as temperatures and velocities. Local heat transfer coefficients and temperature distributions are also reported for the laminar and transitional boundary-layer regions. Results are compared with other experimental data and with theoretical predictions.
An Analysis of Heat Transfer for Fully Developed Turbulent Flow in Concentric Annuli
Authors: Wilson N. W. , Medwell J. O.
Published: February 2012

The heat and momentum transfer analogy is employed to analyze the heat transfer phenomena for turbulent flow in concentric annuli. A modification of the velocity distribution due to Van Driest is assumed and equations in dimensionless form are developed to predict: (a) the position of maximum velocity in the annulus; (b) the friction factor-Reynolds number relationship, and (c) temperature distributions and heat transfer relations over a wide range of Reynolds number and Prandtl modulus.
Convection Heat Transfer From Broad Leaves of Plants
Authors: Parkhurst D. F. , Duncan P. R. , Gates D. M. , Kreith F.
Published: February 2012

This article presents the results of an experimental study designed to determine quantitatively the rates of heat transfer by convection from broad leaves of various plants and trees under conditions approximating those in an ecosystem in nature. Empirical relations, applicable to the different types of leaf shapes found in nature, are derived from the experimental data for free and forced convection. The influences of leaf position relative to the wind or the direction of the gravitational force field, the presence of other branches or leaves in the vicinity, and the flutter in the wind also have been investigated.
Analysis of Three-Fluid, Crossflow Heat Exchangers
Authors: Willis N. C. , Chapman A. J.
Published: February 2012

In this study, the performance of three-fluid, crossflow heat exchangers is determined and presented graphically in terms of the temperature effectiveness of two of the fluids. The effectiveness is determined as a function of heat exchanger size for sets of fixed operating conditions. The introduction of nondimensional operating variables reduces the volume of data required to represent a practical range of operating conditions. The number of boundary conditions for the temperatures is reduced from three to one by the introduction of a nondimensional inlet temperature parameter. Effectiveness factors are determined for a wide range of operating parameters for single-pass, three-fluid heat exchangers. Performance of multipass three-fluid heat exchangers for both cocurrent and countercurrent flow is studied for selected operating conditions.
The Effect of Slot Height and Slot-Turbulence Intensity on the Effectiveness of the Uniform Density, Two-Dimensional Wall Jet
Authors: Kacker S. C. , Whitelaw J. H.
Published: February 2012

This paper presents measurements of the impervious-wall effectiveness of a two-dimensional wall jet obtained using a constant value of lip thickness, 0.032 in. and four slot heights, viz., 0.5, 0.25, 0.132, and 0.074 in. The measurements are in the range of slot-to-free-stream velocity ratio 0.288⩽u¯C/uG⩽2.66 and clearly demonstrate that, in the region where the velocity ratio is close to unity, the effectiveness is greatly dependent upon the slot height. The reason for this dependence is investigated and additional measurements are presented to show that the influence of the slot turbulence intensity on the effectiveness is small. It is concluded that the ratio of slot lip thickness to slot height is the most significant parameter and that the effect of an increase in this ratio is to decrease the effectiveness.
A Numerical Solution for Laminar-Flow Heat Transfer in Circular Tubes With Axial Conduction and Developing Thermal and Velocity Fields
Authors: McMordie R. K. , Emery A. F.
Published: February 2012

This paper describes a numerical calculation of the local Nusselt number for laminar flow in a tube with axial conduction, radial convection, and simultaneously developing thermal and velocity profiles. The results are given for a constant heat flux at the wall and Prandtl numbers from 0.005 to 0.03 with a Pr = 0.7 used to compare with Kays solution.
Photoelastic Observations of Transient Heat Transfer Across a Solid-Fluid Boundary
Authors: King C. Y. , Webb W. W.
Published: February 2012

A new experimental method for observation of rates of transient heat transfer across a solid-fluid boundary is described. Observations of the photoelastic birefringence due to the transient thermal stress in a regular transparent solid can be analyzed to yield effective surface heat transfer coefficients. The method is illustrated by determinations of effective surface heat transfer coefficients for spheres undergoing thermal shocks in several liquids. Resulting values agree with published data obtained by steady state methods. New data are presented for liquid tin and mercury.
Critical-Heat-Flux and Flow-Pattern Observations for Low-Pressure Water Flowing in Tubes
Authors: Bergles A. E. , Lopina R. F. , Fiori M. P.
Published: February 2012

This paper summarizes the results of an investigation of the critical-heat-flux condition for bulk boiling of water in uniformly heated round tubes where the inlet conditions were subcooled and exit pressures were below 100 psia. Choked flow was found to be prevalent under these conditions. The critical heat flux is shown to be a complex function of both local and inlet conditions. Detailed flow-pattern observations were made with an electrical probe. Many of the trends in the critical-heat-flux data can be related to the flow-pattern instability caused by slug flow.
Nonsimilar Boundary-Layer Heat Transfer of a Rotating Cone in Forced Flow
Authors: Koh J. C. Y. , Price J. F.
Published: February 2012

The nonsimilar boundary-layer flow and heat transfer of a cone rotating in a forced-flow field are investigated. Numerical solutions are shown for a half-cone angle of 53.5 deg with parameters (vw/ue)2 ranging from 0 to 20, and with Prandtl numbers from 0.2 to 10. With a half-cone angle of 90 deg (so that one has a rotating disk), the degenerate problem is solved in the same manner.
Heat Transfer to Fully Developed Liquid Metal Flow in Tubes
Authors: Emery A. F. , Bailey D. A.
Published: February 2012

Heat transfer coefficients for fully developed liquid metal flow in a tube with a constant wall heat flux are given for laminar and transitional flow. These experimental values agree with the Graetz value of 4.36, and support the work of Petukhov and Yushin in contradiction to that of Johnson, Hartnett, and Clabaugh.
Radiant Heat Transfer From Isothermal Dispersions With Isotropic Scattering
Authors: Edwards R. H. , Bobco R. P.
Published: February 2012

Two approximate methods are presented for making radiant heat-transfer computations from gray, isothermal dispersions which absorb, emit, and scatter isotropically. The integrodifferential equation of radiant transfer is solved using moment techniques to obtain a first-order solution. A second-order solution is found by iteration. The approximate solutions are compared to exact solutions found in the literature of astrophysics for the case of a plane-parallel geometry. The exact and approximate solutions are both expressed in terms of directional and hemispherical emissivities at a boundary. The comparison for a slab, which is neither optically thin nor thick (τ = 1), indicates that the second-order solution is accurate to within 10 percent for both directional and hemispherical properties. These results suggest that relatively simple techniques may be used to make design computations for more complex geometries and boundary conditions.
Local and Average Heat Transfer and Pressure Drop for Refrigerants Evaporating in Horizontal Tubes
Authors: Altman M. , Norris R. H. , Staub F. W.
Published: February 2012

A test facility is described that has been constructed to investigate local heat transfer and pressure drop for evaporating or condensing refrigerants. The empirical method of B. Pierre [1] for correlating the average heat-transfer coefficients of refrigerants evaporating in horizontal tubes is presented in conjunction with the data of several authors [3–6]. Data on local heat-transfer coefficients and pressure drop are presented for Refrigerant-22 evaporating in two 4-ft-long, 0.343-in-ID straight horizontal tubes, and are correlated by a refinement of the curve proposed in [1]. The procedure of Martinelli-Nelson [9] correlated the data for local pressure drop within 15 per cent.
Heat Transfer to Freon 12 Near the Critical State in a Natural-Circulation Loop
Authors: Holman J. P. , Boggs J. H.
Published: February 2012

An experimental investigation of heat transfer to Freon 12 in the critical region was conducted. A closed natural-circulation loop was used. Correlation of the data is presented. Separate equations are presented for reduced volumes less than one and for reduced volumes greater than one. The investigation covered a range of temperatures from 150 to 400 F and pressures from 500 to 950 psi.
The Heat-Balance Integral—Further Considerations and Refinements
Authors: Goodman Theodore R.
Published: February 2012

Integral methods have previously been applied to transient heat conduction in a slab with constant thermal properties. In this paper the method is extended so as to include temperature-dependent thermal properties in the analysis. In addition, it is shown how to improve the accuracy of a solution by increasing the order of the polynomial used to represent the temperature profile. For the case of a prescribed step surface temperature in a semi-infinite slab, a quartic profile is shown to give excellent accuracy.
The Viscosity of Steam and Water at Moderate Pressures and Temperatures
Authors: Moszynski J. R.
Published: February 2012

The paper reports the results of an investigation of the viscosity of steam and compressed water. The measurements were carried out by means of an oscillating-body-type viscometer in order to develop an alternative method of measurement to the usually employed capillary viscometer, and also to provide an independent check on published data. The results for compressed water, obtained with the aid of an oscillating sphere, represent absolute measurements, and cover a range from 3 to 340 atm and from 20 to 186 C. The viscosity of water is shown to have a negative pressure coefficient below 35 C and a positive coefficient above that temperature. The maximum change in viscosity, at any given temperature over the pressure range covered is 5 per cent. The results show good agreement with previously published data and the deviations of experimental points from smoothed curves do not exceed 0.05 per cent. Although the present instrument is severely limited in range, the feasibility of measurements at elevated temperatures and pressures by means of the oscillation-type viscometer is clearly demonstrated. Particularly striking is the reproducibility and self-consistency of the results obtained.
Burnout in Turbulent Flow—A Droplet Diffusion Model
Authors: Goldmann K. , Firstenberg H. , Lombardi C.
Published: February 2012

Two-phase flow regimes are reviewed briefly. A physical model, which is based on the concept that droplet diffusion through a steam boundary layer is the limiting mechanism for burnout in turbulent flow, is described. An equation is derived relating burnout to other parameters in fog flow. With simplifying assumptions, an order-of-magnitude agreement between analysis and experimental burnout data in fog flow is demonstrated.
The Effect of Density Variation on Heat Transfer in the Critical Region
Authors: Hsu Yih-Yun , Smith J. M.
Published: February 2012

The heat-transfer coefficient between fluid and tube wall in turbulent flow depends upon the physical and thermal properties of the fluid. When density changes across the diameter of the tube are large (for example, when the fluid is near the critical point), the variable density can affect the transfer of momentum and heat. Equations are developed for predicting the magnitude of this effect on the heat-transfer coefficient. Deissler’s [5] expressions for the eddy diffusivity are employed in solving the equations for heat and momentum transfer. For flow in vertical tubes large density variations can also affect the heat transfer by inducing natural convection. By considering the influence of body forces on the shear stress, equations are derived to predict the effect of natural convection on the heat-transfer coefficient for turbulent flow. The results indicate that the effect is significant only for relatively high Grashof numbers and low Reynolds numbers. Such conditions may be encountered in flow of a fluid near its thermodynamic critical point. The derived equations are applied for carbon dioxide flow in the critical region under the conditions for which experimental data were measured by Bringer and Smith [2]. Because of the high Reynolds and low Grashof numbers, natural convection is not significant. However, the effect of the large density variations is found to be significant, and the predicted results agree well with the experimental data.
Radiative Transport Within an Ablating Body
Authors: Kadanoff Leo P.
Published: February 2012

The emission and reabsorption of thermal radiation within a semitransparent material provides a mechanism which supplements ordinary thermal conduction in transporting energy from hotter to colder regions. A method has been developed for the calculation of net radiative flux and temperature distribution within a semi-infinite body which emits, absorbs, and scatters this radiation and which allows some radiation to escape from its surface. This method has been applied to the problem of calculating temperature distributions within bodies in steady-state ablation. The bodies are characterized by their refractive index, surface reflectivity, absorption and scattering coefficient, ablation velocity, and surface temperature as well as by their heat capacity and thermal conductivity. Numerical results are presented for the temperature distribution with various values of these parameters. As a result of this analysis, simple formulas are presented for the temperature distribution very near the surface of an ablating body which are particularly useful in predicting the temperature distribution in the “liquid layer” of a glassy ablating body. These simple formulas are presented for two limiting cases: Case I, in which the liquid layer is so thin that it is almost completely transparent to radiation, and Case II, in which the radiation mean free path is so short that radiative transport can be completely neglected in determining the temperature distribution in the liquid layer. Also resulting from this numerical analysis is a simple relation between the ablation rate and the emissive power of a body in steady-state ablation. The concept of effective conductivity is extended to scattering media. It is noted that this concept fails whenever the temperature or optical properties of the medium change appreciably within one radiation mean free path. In particular, the optical properties change discontinuously at any boundary. Thus, in general, the effective conductivity concept fails near a boundary and results in completely wrong answers for the temperature distribution in the liquid layer.
Oscillations in Two-Phase Flow Systems
Authors: Wallis G. B. , Heasley J. H.
Published: February 2012

This paper contains a mathematical analysis of three modes of oscillation of a simple two-phase flow, natural-circulation system, together with qualitative results of experiments with a small-scale loop model.
Effectiveness and Heat Transfer for a Turbulent Boundary Layer With Tangential Injection and Variable Free-Stream Velocity
Authors: Seban R. A. , Back L. H.
Published: February 2012

The effectiveness and the heat transfer have been measured in a system involving the tangential injection of air from a single spanwise slot into the turbulent boundary layer of an external air stream, with the velocity of the external stream increasing in a way that concentrated the acceleration in a region downstream of the initial mixing zone. The effectiveness was changed but little from the value that would have existed had the free-stream velocity remained at its initial value and both temperature profiles and analytical considerations show that this invariability of the effectiveness is associated with thermal boundary-layer thicknesses that are much larger than the hydrodynamic thicknesses. Heat-transfer coefficients are shown to be predictable from existing information provided that the momentum thickness Reynolds number is large enough.
Laminar Forced Convection of Liquids in Tubes With Variable Viscosity
Authors: Yang Kwang-Tzu
Published: February 2012

Analytical solutions for laminar forced convection of liquids flowing in circular tubes with temperature-dependent viscosity are obtained for both step change in tube-wall temperature and step change in wall heat flux by using an improved integral procedure. The accuracy of this analytical procedure is demonstrated by comparing results for the isothermal problems with that from the exact solutions. Results for the nonisothermal cases are presented in graphical forms in terms of Nusselt numbers, velocity variations at tube center line, and friction factors. Tabulated Nusselt numbers are also given.
Laminar Combined Convection From a Rotating Cone
Authors: Hering R. G. , Grosh R. J.
Published: February 2012

The effect of free convection on heat transfer and on the flow field about a rotating cone is studied. A similar solution for the laminar boundary-layer equations is found to exist when the cone surface temperature varies linearly with distance from the cone apex. The transformed boundary-layer equations contain the important parameter Gr/Re2. This parameter determines the relative importance of the free convection motions on forced convection. Numerical solutions of the transformed equations for aiding flows have been carried out for Prandtl number 0.7 and different values of Gr/Re2. Results are reported for the heat transfer, shear stress, shaft moment, and velocity and temperature fields. Criteria are given for subdividing the regimes of flow as purely free, purely forced, and combined flow. Preliminary experimental heat-transfer results are reported which indicate the trends predicted by theory.
Prediction of Two-Phase Pressure Drop and Density Distribution From Mixing Length Theory
Authors: Levy S.
Published: February 2012

Single-phase turbulent mixing length methods are used to predict two-phase flow. Two-phase density and velocity distributions and two-phase pressure drops are derived by treating the two-phase system as a continuous medium where the turbulent exchanges of momentum and density are equal. Good agreement is obtained between test results and analytical predictions.
An Experimental Investigation of Free-Convection Heat Transfer From Rectangular-Fin Arrays
Authors: Starner K. E. , McManus H. N.
Published: February 2012

Average heat-transfer coefficients are presented for four fin arrays positioned with the base vertical, 45 degrees, and horizontal while dissipating heat to room air. The fins are analyzed as constant-temperature surfaces since the lowest fin efficiency encountered was greater than 98 percent. It was found that coefficients for the vertical arrays fell 10 to 30 percent below those of similarly spaced parallel plates. The 45-degree arrays yielded results 5 to 20 percent below those of the vertical. Two flow patterns were investigated for the horizontal arrays, and it was found that the coefficients could be reduced sharply by preventing three-dimensional flow.
Condensation of Metal Vapors During Rapid Expansion
Authors: Hill P. G. , Witting H. , Demetri E. P.
Published: February 2012

A study has been made of the condensation of metal vapors in nozzles, using the liquid drop nucleation theory, to predict the incidence of condensation and its effect on the properties of the fluid stream. The theory, which has been verified by accurate experimental data on steam, predicts that in the absence of charged particles initially saturated mercury vapor, for example, is very reluctant to condense in a nozzle. On the other hand, the vapors of sodium, potassium, and rubidium should condense very readily. In each case the typical size and growth rate of the condensed drops is so small that significant slip between vapor and liquid phases is very unlikely to develop. The nucleation process is rapid so that equilibrium is approached quickly. In reasonably long nozzles it may be quite in order to idealize the transition between supersaturated and equilibrium states as a step change.
The Transition From Slug to Homogeneous Two-Phase Flows
Authors: Moissis R.
Published: February 2012

An analysis is presented which describes and predicts the process of transition from the nonhomogeneous slug to the homogeneous fog or frothy flow regime in the flow of two-phase mixtures in vertical pipes. The results compare favorably with existing visual flow regime studies.
Critical Heat Flux for Subcooled Water Flowing Normal to a Cylinder
Authors: Vliet G. C. , Leppert G.
Published: February 2012

Empirical data are presented which show the effects of diameter, water velocity, and subcooling on the critical heat flux from an electrically heated, cylindrical lube or wire. The maximum flux which can be accommodated in subcooled nucleate boiling is found to vary directly with the water velocity and subcooling and inversely with a fractional power of the heater diameter. The exponent which describes the diameter dependence is itself a function of both velocity and subcooling. Measurements of the critical flux are reported for water at atmospheric pressure over a range of subcooling from 3 to 100 deg F, velocity from 0.5 to 11 ft/sec, and heater diameter from 0.010 to 0.189 in. Visual and photographic observations indicate a marked effect of subcooling on the flow mechanism near the critical heat flux. High subcooling prevents the formation of the vapor cavity which was described in the previous paper [1] for nearly saturated water, although the failure of nucleate boiling still occurs at the rear of the cylinder and is accompanied by a concentration of vapor in that region.
Heat Transfer to Mercury Flowing In-Line Through a Bundle of Circular Rods
Authors: Maresca M. W. , Dwyer O. E.
Published: February 2012

Experimental results were obtained for the case of in-line flow of mercury through an unbaffled bundle of circular rods, and they were compared with theoretical predictions. The bundle consisted of 13 one-half-in-dia rods arranged in an equilateral triangular pattern, the pitch:diameter ratio being 1.750. Measurements were taken only on the central rod. Six different rods were tested. All rods in the bundle were electrically heated to provide equal and uniform heat fluxes throughout the bundle. The rods were of the Calrod type. The test rods had copper sheaths with fine thermocouples imbedded below the surface for measuring surface temperatures. Some rods were plated with a layer of nickel, followed by a very thin layer of copper, to provide “wetting” conditions, while others were chromeplated to provide “nonwetting” conditions. Heat-transfer coefficients were obtained under the following conditions: (a) Prandtl number, 0.02; (b) Reynolds number range, 7500 to 200,000; (c) Peclet number range, 150 to 4000; (d) “Wetting” versus “nonwetting”; (e) Both transition and fully established flow; (f) Variation of Lf/De ratio from 4 to 46. The precision of the results is estimated to be within 2 to 3 percent. An interesting finding, consistent with earlier predictions, was that the Nusselt number, under fully established turbulent-flow conditions, remained essentially constant, at the lower end of the turbulent flow regime, until a Reynolds number of about 40,000 was reached.
The Dominant Unstable Wavelength and Minimum Heat Flux During Film Boiling on a Horizontal Cylinder
Authors: Lienhard J. H. , Wong P. T. Y.
Published: February 2012

Predictions of the dominant unstable wavelength and the minimum heat flux during film boiling above a flat plate are found to be inapplicable in the case of boiling on small wires. New expressions are developed for the case of a horizontal cylinder, by accounting for the effect of surface tension in the transverse direction upon the Taylor instability of the interface. Original measurements of wavelengths and minimum heat fluxes on small wires are also provided. These data support the predictions.
Diffusion Approximation for Thermal Radiation in Gases With Jump Boundary Condition
Authors: Deissler R. G.
Published: February 2012

Generalized equations are obtained for radiative diffusion in a nongray gas and for the energy jump at a wall. By using the second-order energy jump at a wall, the diffusion approximation for radiation in a gas is improved considerably, the range of validity of the approximation being extended to lower values of optical thickness.
A Visual Study of Two-Phase Flow While Evaporating in Horizontal Tubes
Authors: Zahn W. R.
Published: February 2012

A review of the literature shows no data for horizontal two-phase one-component flow with evaporation; therefore, visual studies have been made of the flow patterns of evaporating R-22 (commercially pure dichloro-difluoro-methane) inside horizontal tube sections under pressure, temperature, flow, and heat load conditions simulating actual operation of a small air-conditioning coil. Description of the patterns observed are given along with data to use in checking with volume flow fraction, Froude number flow regime maps and with maps using Baker’s [1] parameters. A discussion on the qualitative relation between coefficients, the type of flow, effect of return bends, and flow instabilities is included.
Anisotropic, Multiply Scattered Radiation From an Arbitrary, Cylindrical Source in an Infinite Slab
Authors: Chin J. H. , Churchill S. W.
Published: February 2012

An approximate, analytical solution is developed for the intensity of electromagnetic radiation resulting from a line or cylindrical source located within and normal to the boundaries of an infinite slab of purely scattering material. The source strength is allowed to vary arbitrarily along the line or cylinder, and the slab is considered to have one absorbing (or open) surface and one partially reflecting surface. The problem represents an idealization of the attenuation of thermal radiation from a nuclear fireball within a layer of fog or a dispersion of oil particles. The six-flux resolution of scattered energy proposed by Chu and Churchill is utilized. In general, machine computations are needed to obtain numerical results. Approximations are suggested for use in the indicated computations. Illustrative numerical results are presented.
Heat Conduction in the Infinite Medium With Lines of Discontinuities
Authors: Sih G. C.
Published: February 2012

A mathematical analysis of heat conduction in the infinite region with lines of discontinuities by application of complex variables and the problem of linear relationship is considered. Boundary problems for the plane with straight cuts or inclusions are formulated and solutions are given in closed form. The heat fluxes were found to possess the characteristic inverse square-root singularity in terms of the radial distance from the point of the line of discontinuity, hence approaching high mathematically infinite values at the point itself. It is also shown that the magnitude of the heat flux vector may be obtained from a sectionally holomorphic function without calculating the temperature distribution in the body.
Radiant Heat Transfer to Earth Satellites
Authors: Watts R. G.
Published: February 2012

A method is presented for easily evaluating view factors to interplanetary bodies. A simple approximate relation is suggested for albedo radiation under certain, not-too-restrictive conditions.
Phase Velocities in Boiling Flow Systems by Total Energy and by Diffusion
Authors: Polomik E. E.
Published: February 2012

A total energy balance is employed in a single-component boiling flow system to obtain minimum limiting values of vapor volume content and show the effects of phase velocity distributions. Results are compared to data of various investigators in steam-water systems at pressures of 115 to 1000 psia. Limiting equations are used for derivation of more accurate relationships. A correlating function and equation are derived, from the generalized diffusion velocity for momentum, which relate voids, quality, and kw/liter. These are used to correlate Argonne’s steam voids data in a boiling channel at 163 and 614 psia with velocities in the range 1.83 to 5.94 ft/sec and steam qualities between 0.008 and 0.07. A simple, semitheoretical relationship between quality, vapor fraction, and energy addition/unit boiling volume is obtained which correlates all of the 163 psia data within about 5 percent, and a limited amount of data for 614 psia equally well.