VII.–The Effect of the Transport of Heat on the Rate of Evaporation of Small Droplets I. Evaporation into a Large Excess of a Gas

1962 ◽  
Vol 66 (2) ◽  
pp. 65-80
Author(s):  
P. G. Wright
Keyword(s):  
Gaseous Phase ◽  
The Other ◽  
Total Resistance ◽  
Large Excess ◽  
Stationary Growth ◽  
In Series ◽  
Finite Period ◽  
Rate Of Evaporation ◽  
Latent Heat Of Vaporization ◽  
Algebraic Formulation

SynopsisBeginning with fundamental results obtained by Mason for the effect of self-cooling on the evaporation of drops, and by Fuchs for the diffusional retardation of evaporation for small droplets of any radius, explicit expressions for the effect of the transport of heat on the rate of quasi-stationary growth or evaporation, are discussed.The simplest algebraic formulation of the results lends itself to interpretation as expressing a resistance to evaporation, the total resistance being the sum of four resistances in series. Two of these resistances, one to diffusion and one to the conduction of heat, are offered by the gaseous phase in bulk; and there are two corresponding resistances at the interface. Corrections are formulated for the effect of the heating of the droplet by radiation. These corrections may be expressed as a (finite) resistance in parallel with the other two resistances to the transfer of heat. Simplified equations are obtained for the evaporation of a liquid whose latent heat of vaporization is very large.Some remarks are made on the formation of a monodisperse aerosol by the growth of smaller droplets. Integrated expressions are obtained for particular cases of the evaporation of a droplet over a finite period of time.

III.—On the Reduction of Ferric Iron (1) by Sulphurous Acid and (2) by Zinc Dust

1913 ◽  
Vol 32 ◽  
pp. 12-16
Author(s):  
Alexander Charles Cumming ◽  
E. W. Hamilton Smith
Keyword(s):  
Sulphuric Acid ◽  
Carbonate Rocks ◽  
Ferric Iron ◽  
Zinc Dust ◽  
The Other ◽  
Additional Contribution ◽  
Large Excess ◽  
Other Hand

So many papers have appeared on this subject that some apology seems desirable before making an additional contribution. The amount of published work on reduction with sulphurous acid is in itself an indication that many workers have found difficulties. It has been shown that the reduction does not take place in presence of large excess of hydrochloric or sulphuric acid, but the reduction will still occur while the reaction of the solution is strongly acid. On the other hand, Hillebrand (“Analysis of Silicate and Carbonate Rocks,” U.S. Bulletin, 442, p. 113) states if the solution after addition of sulphite is red in colour, it is too alkaline and acid must be added.

The Frequency of Pericardial Effusions in Bacterial Meningitis

PEDIATRICS ◽  
1979 ◽  
Vol 63 (5) ◽  
pp. 764-770
Author(s):  
W. Pennock Laird ◽  
John D. Nelson ◽  
F. Douglas Huffines
Keyword(s):  
Risk Factors ◽  
Bacterial Meningitis ◽  
Antibiotic Therapy ◽  
Significant Risk ◽  
Literature Survey ◽  
The Other ◽  
Purulent Pericarditis ◽  
Pericardial Effusions ◽  
In Series ◽  
A Prospective Study

Because of our experience with four cases of purulent pericarditis complicating bacterial meningitis during a 13-month period, we performed a prospective study to determine the frequency of this complication. Echocardiograms were done on 100 patients with bacterial meningitis. Small or moderate pericardial effusions were detected in 19 patients, but none had symptoms or signs related to the effusion. Pericardiocentesis was done in one infant; all the other effusions resolved spontaneously. Patients with effusion were significantly younger than those without this complication, but no other significant risk factors were identified. A literature survey indicated that symptomatic pericarditis occurs in fewer than 1% of patients with meningitis. Conversely, in series of cases of purulent pericarditis, associated meningitis was reported in 12% of patients. We concluded that pericardial infection is common in patients with meningitis but that it is usually of no clinical significance and resolves with antibiotic therapy.

An Empirical Formula to Estimate the Resistance of a Convoy in a Restricted Waterway

1996 ◽  
Vol 40 (02) ◽  
pp. 107-111
Author(s):  
J.L.J. Marchal ◽  
Y.-D. Shen ◽  
D. Kicheva
Keyword(s):  
Cross Section ◽  
Empirical Formula ◽  
The Other ◽  
Total Resistance ◽  
Empirical Methods ◽  
Joint Research ◽  
Ship Hydrodynamics ◽  
Joint Research Project ◽  
Length Width ◽  
The Subject

An examination of the literature produced very few references related to the subject of estimating the resistance of a convoy navigating in a waterway of limited cross section. This paper reports the findings of one such study—a joint research project undertaken by Belgium's University of Liege and the Bulgarian Ship Hydrodynamics Centre. A polynomial is presented here for evaluating the total resistance of a convoy moving in a restricted waterway. The resistance was found to depend on Froude number and on the relative dimensions (length, width and depth) between the convoy and the channel. The results obtained by the suggested polynomial are compared with those obtained by the other three existing empirical methods.

Numerical Modelling of a Planing Craft with a V-Shaped Spray Interceptor Arrangement in Calm Water

2020 ◽  
Author(s):  
Mikloš Lakatoš ◽  
Kristjan Tabri ◽  
Abbas Dashtimanesh ◽  
Henrik Andreasson
Keyword(s):  
Reaction Force ◽  
The Other ◽  
Numerical Comparison ◽  
Total Resistance ◽  
Stagnation Line ◽  
Planing Craft ◽  
Water Conditions ◽  
Calm Water ◽  
Wetted Surface Area ◽  
Novel Concept

V-shaped spray interceptors are a novel concept of spray deflection on planing craft. Conventional spray rails are positioned longitudinally on the bottom of the hull and detach the spray from hull deflecting it towards the sides or slightly down and aftward. The V-shaped spray interceptors, on the other hand, are located in the spray area forward of the stagnation line such that they would deflect the oncoming spray down and aftward, thereby producing a reaction force that reduces the total resistance. An experimental study reported that the V-shaped spray interceptors to reduce the total resistance at low planing speed by up to 4%. This paper features a numerical comparison of two planing craft, one equipped with a conventional setup of longitudinal spray rails and the other with a V-shaped spray interceptor. Both configurations were simulated in calm water conditions and were free to pitch and heave in a speed range of Fr∇ = 1.776 to 3.108. The numerical model was analyzed for grid sensitivity and numerical results were compared with experimental results. The two concepts were compared in terms of total resistance, lift, running position and wetted surface area. Conventional spray rails were shown to account for up to 5.6% of total lift and up to 6.5% of total resistance. The V-shaped spray interceptor was shown to reduce the total resistance by up to 8%. Since the V-shaped spray interceptor was located in the spray area forward of the stagnation line, it deflected the oncoming spray thereby producing a horizontal reaction force (-1.5% of RTM) in the direction of the craft’s motion. The rest of differences in the total resistance of the hulls equipped with the conventional spray rails and the V-shaped spray rails was due to absence of the resistance of the absent spray rails.

The diffusion of load from a stiffener into an infinite elastic sheet

1957 ◽  
Vol 239 (1218) ◽  
pp. 296-310 ◽  
Keyword(s):  
Mixed Boundary ◽  
Functional Differential Equations ◽  
Mixed Boundary Conditions ◽  
Limited Range ◽  
The Other ◽  
Shear Stresses ◽  
Variable Theory ◽  
Elastic Sheet ◽  
Complex Variable Theory ◽  
In Series

The use of complex variable theory to express problems in generalized plane stress is well known, but methods of finding particular solutions are available for only a limited range of problems. This paper and its sequel will develop a new technique, reducing certain problems with mixed boundary conditions to second order functional differential equations, whose solutions can be found in series form. Exact solutions are given to three fundamental problems of the diffusion of load in an infinite two-dimensional elastic sheet to which a semi-infinite elastic stiffener is continuously attached throughout its length. The first problem has a load applied to the end of the stiffener, with its line of action along the stiffener and its reactions at infinity. In the other two problems the stiffener end is unloaded but a uniform tension is applied to the sheet at infinity, in one case parallel to the stiffener, in the other perpendicular to it. Expressions for the load in the stiffener and for the direct and shear stresses in the sheet are found and plotted in non-dimensional form.

Reliability and barrier assessment of series–parallel systems subject to cascading failures

2020 ◽  
Vol 234 (3) ◽  
pp. 455-469 ◽  
Author(s):  
Lin Xie ◽  
Mary Ann Lundteigen ◽  
Yiliu Liu
Keyword(s):  
Block Diagram ◽  
Parallel Systems ◽  
The Other ◽  
Cascading Failures ◽  
Practical Case ◽  
Aggregation Method ◽  
Safety Barriers ◽  
Parallel Structures ◽  
In Series ◽  
Technical Systems

Cascading failures can occur in many technical systems where the components are organized as in series–parallel structures. The failures in these systems may propagate from one component to the other, not only within the same parallel sub-structure but also between different sub-structures. This article presents a recursive aggregation method based on the extended models of reliability block diagram, for analyzing the impacts of cascading failures on the reliability of series–parallel systems. Based on the reliability analysis, the effects of safety barriers on preventing cascading failures are studied, and the importance of safety barriers at different locations is evaluated. One simple example of three components and one practical case from an oil production system are presented. The findings in these case studies illustrate how system designers and safety managers can identify the effective and reasonable ways of installing safety barriers by using the proposed approaches, for the mitigation of cascading failures in series–parallel technical systems.

Photometric investigations of alkali metals in hydrogen flame gases - II. The study of excess concentrations of hydrogen atoms in burnt gas mixtures

1956 ◽  
Vol 235 (1200) ◽  
pp. 89-106 ◽  
Keyword(s):  
Hydroxyl Radicals ◽  
Alkali Metals ◽  
Equilibrium Constants ◽  
The Other ◽  
Large Excess ◽  
Hydrogen Atoms ◽  
Free Hydrogen ◽  
Hydrogen Flame ◽  
Photometric Measurements ◽  
Oxygen Flame

Photometric measurements on alkali metals in hydrogen-oxygen flame gases, diluted with various proportions of nitrogen, are interpreted as giving a measure of the concentration of free hydrogen atoms, which persist in these gases for several milliseconds after primary combustion. These concentrations are well in excess of those expected from thermodynamic equilibrium, especially towards the lower end of the range of temperatures studied (2400 to 1600°K). Two kinds of measurement have been made. (i) Comparison of the intensities of the Na D lines and the Li resonance doublets, for equal traces of the two elements present in the gases. The amount of free lithium is modified by the balanced process, Li + H 2 O ⇌ LiOH + H, whereas corresponding reactions for sodium are negligible. Using estimated equilibrium constants for these reactions, [H] can be obtained. (ii) Measurements of the change in intensity of the Na D lines when 0∙01 to 0∙5% of chlorine or its compounds (a large excess over the sodium) are added to the flame gases. NaCl is considered to be formed by the balanced reactions Na + HCl ⇌ NaCl + H. The concentration of HCl, the most important chlorine compound in the hydrogen-rich flame gases, may be obtained from the total chlorine added. Using estimated equilibrium constants for the above reaction, [H] can again be obtained. The agreement between the [H] values obtained by these two independent methods is good. The decrease of [H] with height in the gases is consistent with ternary recombination towards full equilibrium. A general discussion of excess radical concentrations in hydrogen flame gases is given, for hydroxyl radicals and oxygen atoms as well as hydrogen atoms. The conclusions reached are supported by experimental evidence. A further discussion of the way in which the amounts of chlorine used in the experiments may affect the other radical concentrations is given.

Larval development of ovine Neostrongylus linearis in four experimentally infected mollusc species

1994 ◽  
Vol 68 (3) ◽  
pp. 207-210 ◽  
Author(s):  
M.Y. Manga-González ◽  
M.P. Morrondo-Pelayo
Keyword(s):  
Post Infection ◽  
The Other ◽  
Snail Species ◽  
Intermediate Hosts ◽  
Cepaea Nemoralis ◽  
In Series ◽  
Mollusc Species ◽  
Higher Temperature ◽  
The One ◽  
First Time

AbstractDevelopment of Neostrongylus linearis larvae was studied in the snail intermediate hosts Oestophora (Oestophora) barbula, Oestophorella buvinieri, Cepaea nemoralis and Helix (Cryptomphalus) aspersa. The molluscs of each species, all adults, were divided into groups of 40 for infection purposes. The infection doses for the first two snail species were 90 and 50 first stage larvae (L1) of N. linearis, respectively. For C. nemoralis two batches were tested: one with 200 L1 kept at 19°C and the other with 250 L1 at a temperature of 21°C. The same was done with Helix (C.) aspersa with 200 L1 at a temperature of 21°C, on the one hand and 300 L1 at 24°C on the other. One or two molluscs of each species were killed in series from the 6th day post-infection (p.i.) until the 44th. Percentage values for total larvae (1, 2 and 3) and L3 were higher with the lower dose for C. nemoralis, whilst the same was true with the higher dose in Helix (C.) aspersa. In both cases, the higher temperature appeared to contribute to cycle acceleration. Using one way analysis of variance, statistically significant differences were detected between the species of molluscs tested concerning percentages of L1 which penetrated, total larvae and L3. According to our results, the decreasing order of susceptibility of these species of molluscs as experimental intermediate hosts of N. linearis is: O. buvinieri, Oestophora (O.) barbula, C. nemoralis and Helix (C.) aspersa. It is the first time that Oestophora (O.) barbula and Oestophorella buvinieri have been named as experimental intermediate hosts of N. linearis.

Approaches to Predicting the Vertical Transmissibility of a Suspension Seat With a Seated Subject

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Jun Wu ◽  
Meihuan Wang ◽  
Yi Qiu
Keyword(s):  
High Frequency ◽  
Dynamic Stiffness ◽  
The Other ◽  
Human Model ◽  
Apparent Mass ◽  
Frequency Range ◽  
Air Suspension ◽  
In Series ◽  
Inert Mass ◽  
Good Agreement

Abstract In this paper, four methods were put forward to predict the transmissibility of an air suspension seat with a seated subject. For characterizing the dynamics of the suspension seat, two of the methods were based on developing a model of the air suspension seat and calibrating the parameters using the transmissibilities of the suspension and complete seat respectively with an inert mass from the experiment. The other two methods substituted the detailed modeling of the seat by two dynamic stiffness connecting in series calculated from two same transmissibilities measured in the experiment. For characterizing the biodynamics of the human body, two of the methods took advantage of the normalized apparent mass from published papers to take the place of the human model, while the other two methods made use of one measured seat transmissibility with a subject to deduce the apparent masses of all the subjects. Good agreement was illustrated between the experiment and model prediction for all the four methods. In addition, it also exhibited that a large discrepancy can be resulted in, especially in the high-frequency range, if the seat model was substituted by one integrated dynamic stiffness.

Rises in whole muscle passive tension of mammalian muscle after eccentric contractions at different lengths

2003 ◽  
Vol 95 (3) ◽  
pp. 1224-1234 ◽  
Author(s):  
N. P. Whitehead ◽  
D. L. Morgan ◽  
J. E. Gregory ◽  
U. Proske
Keyword(s):  
Isometric Tension ◽  
The Other ◽  
Medial Gastrocnemius ◽  
Eccentric Contractions ◽  
Passive Tension ◽  
Active Length ◽  
Before And After ◽  
Two Factors ◽  
In Series ◽  
Whole Muscle

This is a report of experiments carried out on the medial gastrocnemius muscle of the anesthetized cat, investigating the effects of eccentric contractions carried out at different muscle lengths on the passive and active length-tension relationships. In one series of experiments, the motor supply to the muscle was divided into three approximately equal parts; in the other, whole muscles were used. Fifty eccentric contractions were carried out over different regions of the active length-tension curve for each partial or whole muscle. Active and passive length-tension curves were measured before and after the eccentric contractions. When eccentric contractions were carried out at longer lengths, there was a larger shift of the optimum length for active tension in the direction of longer muscle lengths and a larger fall in peak isometric tension. Passive tension was higher immediately after the eccentric contractions, and if the muscle was left undisturbed for 40 min, it increased further to higher values, particularly after contractions at longer lengths. A series of 20 passive stretches of the same speed and amplitude and covering the same length range as the active stretches, reduced the passive tension which redeveloped over a subsequent 40-min period. It is hypothesized that there are two factors influencing the level of passive tension in a muscle after a series of eccentric contractions. One is injury contractures in damaged muscle fibers tending to raise passive tension; the other is the presence of disrupted sarcomeres in series with still-functioning sarcomeres tending to reduce it.

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