Cannon Balls Research Articles

Conflicts Of Interest And Preserving The Objectivity Of Scientific Research

Conflicts Of Interest And Preserving The Objectivity Of Scientific Research

On the X‐Ray Lines in the Afterglows of Gamma‐Ray Bursts

The observation of X-ray lines in the afterglow of GRB 011211 has been reported, and challenged. The lines were interpreted as blueshifted X-rays characteristic of a set of photoionized metals, located in a section of a supernova shell illuminated by a gamma-ray burst (GRB) emitted a couple of days after the supernova explosion. We show that the most prominent reported lines coincide with the ones predicted in the cannonball model of GRBs. In this model, the putative signatures are hydrogen lines, boosted by the (highly relativistic) motion of the cannonballs (CBs). The corresponding Doppler boost can be extracted from the fit to the observed I-, R-, and V-band light curves of the optical afterglow of GRB 011211, so that, since the redshift is also known, the line energies are (in the CB model) predicted. We also discuss other GRBs of known redshift which show spectral features generally interpreted as Fe lines, or Fe recombination edges. The ensemble of results is very encouraging from the CB model's point of view, but the data on each individual GRB are not good enough to draw (any) objectively decisive conclusions. We outline a strategy for X-ray observers to search for lines which, in the CB model, move predictably from higher to lower energies.

Report on the first research campaign on the Napoleonic brick, Mercure, wrecked off Lignano, Udine, Italy in 1812

During 2001, the NAUSICAA office organized a research campaign on the site where two carronades had been retrieved by a fishing boat. Side-scan sonar research led to the discovery of a mound and six more carronades. The mound was composed of iron ingots, cannon balls, and tools reused as ballast. After the cleaning of a carronade, it was possible to read the name of the foundry, Du Creusot, and the date, 1806. This evidence was sufficient to identify this as the wreck of the Napoleonic brick, Mercure, lost during the Battle of Grado, fought between an English and French fleet in February 1812.

On the optical and X-ray afterglows of gamma ray bursts

We severely criticize the consuetudinary analysis of the afterglows of gamma-ray bursts (GRBs) in the conical-ejection fireball scenarios. We argue that, instead, recent observations imply that the long-duration GRBs and their afterglows are produced by highly relativistic jets of cannonballs (CBs) emitted in supernova explosions. The CBs are heated by their collision with the supernova shell. The GRB is the boosted surface radiation the CBs emit as they reach the transparent outskirts of the shell. The exiting CBs further decelerate by sweeping up interstellar matter (ISM). The early X-ray afterglow is dominated by thermal bremsstrahlung from the cooling CBs, the optical afterglow by synchrotron radiation from the ISM electrons swept up by the CBs. We show that this model fits simply and remarkably well all the measured optical afterglows of the 15 GRBs with known redshift, including that of GRB 990123, for which unusually prompt data are available. We demonstrate that GRB 980425 was a normal GRB produced by SN1998bw, with standard X-ray and optical afterglows. We find that the very peculiar afterglow of GRB 970508 can be explained if its CBs encountered a significant jump in density as they moved through the ISM. The afterglows of the nearest 8 of the known-redshift GRBs show various degrees of evidence for an association with a supernova akin to SN1998bw. In all other cases such an association, even if present, would have been undetectable with the best current photometric sensitivities. This gives strong support to the proposition that most, maybe all, of the long-duration GRBs are associated with supernovae. Although our emphasis is on optical afterglows, we also provide an excellent description of X-ray afterglows.

A note on casting iron cannon balls: ideality and porosity

A note on casting iron cannon balls: ideality and porosity

Volcanic bombs—their form and physical structure: comparison with cast iron cannon balls

Volcanic bombs are ejected clots of hot viscous magma of smallest dimension about 2½ in. (50mm) dia. After cooling down, their internal structure reflects the residual stresses within their hard “spherical” shell. This we suppose is the same, at least in kind, as that calculated for cast iron spherical cannon balls which is described in Ref. [I] [ Johnson and Chandrasekar, J. Mater. Processing Technol. , in press (1992) ]. A tensile, and therefore “spongy”, central region was predicted and if it should be relieved by virtue of an imperfection then a simple void would be able to be developed. In the case of cannon balls, off-centre voids will not allow it to be shot “true”. It is alleged that all cast iron balls are so flawed, but as far as the authors know no substantial evidence of such has been presented. Verificatory physical evidence by way of similarity with what is known and seen from the terminal state of cooled magma bombs—deriving from the study of vulcanology—is remarkable. A short catalogue of what can be found out about them is given.

Up Close: Materials Science in Spain—Its Dynamic Growth

The year 1992 is very special for Spain: 500 years have passed since the discovery of the American continent. That discovery helped make Spain the most powerful country in the world in the 16th century. In time, though, Spain lost its influence to England, and materials processing played a surprising role in this transfer. It has been shown that one of the main reasons Spain's “Invincible Armada” was defeated by the English Navy was that the Spanish ships used faulty cannon balls. The balls were of such poor quality that, once fired, they disintegrated before they could damage enemy warships. Faulty material technology—low compactness or degree of sintering—caused the disintegration.As we approach the 21st century, the Spanish scientific community has reached a high level of expertise in materials science. A decade ago, Spain's R&D activities were poorly funded and research was carried out without the necessary infrastructure. In 1986, the government established a national R&D strategy which included a dedicated Program for New Materials. In addition, the Regional Communities (Autonomias) have reinforced these nationally planned and funded R&D activities. And as a member of the European Community (EC), Spain has also begun integration into European R&D. After three years, Spanish scientists are already achieving success in the Brite/Euram Program at a level comparable to more scientifically and technologically advanced countries. Figure 1 shows the Spanish government's total R&D budget in materials science from 1985 to 1991, and additions from the EC since 1989. Clearly, financial support for materials science has increased dramatically in the last few years.

Mostly on oak targets and 19th century naval gunnery

The performance of oak planks due to impact mainly from cannon balls of up to about 8 in (20 cm) diameter moving at ∼ 1500 ft s −1 briefly summarized from a mid-19th century treatise. Penetration, splintering and related aspects of such a dynamic encounter are described.

From Classic to Classy: Changing Fashions in Street Names

Street names in Athens, Georgia, are of two kinds: older, traditional, central, commemorative, directional = “classic,” and newer, innovative, suburban, evocative, given by real-estate developers for their commercial appeal = “classy.” The city of Athens is the site of the University of Georgia, the State Botanical Garden, the Georgia Museum of Art, and notably a double-barreled cannon, which was supposed to fire two chain-linked cannon balls simultaneously, but which succeeded on its trial shot only in demolishing a fence and killing a cow. The city was consolidated with Clarke County, yielding a population of some 120,000.

Wasa's cannon balls saved from corrosion

Wasa's cannon balls saved from corrosion

Columbia Offers Colorful History, Garden Trails

The South Carolina Capitol, which AEJ conventioners will see, was under construction when General Sherman's troops occupied Columbia in February 1865. Cannon balls were bounced off the walls from across the river before Northern troops entered the city, and the points of impact are clearly marked for inspection.

The Early Casting of Iron: A Stage in Iron Age Civilization

V ESPITE the large amount of work that has been done on the history of iron and the important way in which that metal is interrelated with archeological studies, in both the geographical and the historical fields, very little scholarly research has been directed towards the discovery of the casting of iron and its implications. Archeologists and geographers are generally unfamiliar with the technical processes involved, while conversely mineral technologists are unfamiliar with the geographical and cultural aspects. Two recent writers in the metallurgical field have supported the erroneous belief, widely held, that iron was not cast before the Middle Ages. J. Newton Friend concludes his Iron in Antiquityl with brief note on the discovery of cast which he ascribes to accident in the operation of the German stiickofen in the Middle Ages. But museums have many specimens of cast iron that antedate medieval times by more than a thousand years. T. A. Rickard in his Man and Metals says: making of cannon, and more particularly the making of cannon-balls, was the chief incentive to the invention of cast-iron.2 The need for a cheap metal from which to cast cannon balls and cannon did indeed furnish a new use for cast iron, while the stiickofen made it cheap. But cast iron had been used for other purposes more than a thousand years before.

The magnetron

In presenting to you this youngest member of the electron tube family, I am both aided and embarrassed by its family history. I am aided by the fact that you are already acquainted with electrons, so that I need waste no time in explanation or argument regarding their existence. You believe in these little cannon balls which jump out of the hot filament, fly across the vacuum, and plunge into the anode. You have seen them heat the tungsten anode of an X-ray tube to its melting-point in a fraction of a second. Most of you believe that when a current flows through a wire it is these same little electrons, and nothing else, that stream through the wire, like water flowing through a pipe.

On Measuring the Vibratory Periods of Tuning-Forks

THE tuning-fork when its number of double vibrations, to and from in a second, or briefly its frequency, has been ascertained, is a most convenient instrument for measuring minute divisions of time. As such it is now extensively used for physical, physiological, and military purposes (velocity of bullets and cannon balls). The antecedent difficulty of ascertaining the frequency, is however very great. The old processes, sufficient for roughly ascertaining musical pitch, and depending upon wires of known weight, length, and tension, or the action of the siren, are totally insufficient for modern purposes. It was the contradictory nature of the results furnished by the monochord in the division of the Octave into twelve equal parts that led Scheibler to his system of a series of tuning-forks differing from one another by known numbers of vibrations, leading to countable beats, and extending over an Octave. Nothing can he more convenient to use than such a series of forks for all musical purposes. They enable the frequency not only of any small as well as large tuning-fork, but also of any sustained tone to be ascertained within one-tenth of a vibration, that is, one vibration in ten seconds. The writer has for some years been in the constant habit of using such a set of forks with the most satisfactory results. His own forks were measured by Scheibler's (exhibited in the Historic Loan Collection of Musical Instruments at the Albert Hall this year), but extend over a greater range, from about 224 to about 588 vib., that is, rather more than an Octave and a major Third. The great advantage of such a tonometer is extreme portability, immediate application to any sustained tone (even that of a pianoforte string), and the independence of the result from any (almost always imperfect) estimation of unison by a musical ear. There are of couise antecedent difficulties in ascertaining the pitch of each particular fork, but these are overcome by patient observation, the extension of the series beyond an Octave furnishing in itself the required check.

Loch leven castle: its keys and cannon balls

Loch leven castle: its keys and cannon balls

LXXXV. Observations concerning a method of defending ships and fortifications against cannon balls, and of causing them to fly back again on the enemy

LXXXV. <i>Observations concerning a method of defending ships and fortifications against cannon balls, and of causing them to fly back again on the enemy</i>

III. The force of gun-powder, and the initial velocities of cannon balls, determined by experiments; from which is also deduced the relation of the initial velocity to the weight of the shot and the quantity of powder.

These experiments I made at Woolwich in the summer of the year 1775, assisted by several able officers of the royal artillery at that place, and other ingenious gentlemen.