scholarly journals II.—On a Skull of Bos Primigenius Perforated by a Stone Celt

1874 ◽  
Vol 1 (11) ◽  
pp. 492-496 ◽  
Author(s):  
James Carter
Keyword(s):  
Frontal Bone ◽  
Present Condition ◽  
Positive Evidence ◽  
Extinct Species

In 1863 the skull and a portion of the skeleton of a large extinct species of Ox (B. primigenius), which had been found in the peat of the Cambridgeshire Fens, and which apparently had been killed by a celt, was placed in the Woodwardian Museum at Cambridge. At the time of its deposition there a portion of the flint remained firmly fixed in a fracture in the frontal bone, being partially retained in sitû by a mass of peat: as, however, this peat gradually dried, it crumbled away, and the celt became loosened and displaced; moreover, some small fragments of bone fell away from the margin of the wound, so that in its present condition the specimen merely exhibits an irregular fracture in the forehead, in which a fragment of a flint implement lies loosely; but it no longer furnishes conclusive and positive evidence to prove that the fracture was actually caused by the celt which occupies it.

scholarly journals Young Stages of Zeugopterus punctatus

1894 ◽  
Vol 3 (3) ◽  
pp. 202-205 ◽  
Author(s):  
J. T. Cunningham
Keyword(s):  
Frontal Bone ◽  
The Other ◽  
Terminal Portion ◽  
Facial Region ◽  
The Core ◽  
Dorsal Fin ◽  
Undifferentiated Cells ◽  
Auditory Region ◽  
The Right

On May 4th of the current year a number of small Pleuronectids were captured by the hand in a pool left by the ebb tide at Plymouth Breakwater, and brought to me alive. Two of them were very transparent, and, from their habit of lying on the right side when at rest, evidently sinistral forms. One of them was almost perfectly symmetrical; while in the other the torsion of the facial region and eyes had commenced. The pigmentation had the form of interrupted transverse bands, which were most conspicuous on the dorsal and ventral fins; on the dorsal fin seven bands were indicated. The terminal portion of the original trunk, containing the notochord, was seen at the upper edge of the caudal fin. The neurochord was covered with pigment, forming a very distinct band, situated, however, not in the skin, but in the connective tissue surrounding the neurochord or spinal cord. The mouth was large, and the snout upturned. The pectoral fin was large, the pelvic small. But the most important characteristic was the presence of two straight spines projecting laterally from the auditory region. These have been called otocystic spines by Prof. McIntosh, but I think they would be more appropriately described as periotic spines, as they are evidently projections of the periotic cartilage or bone; to which particular bones of the periotic region they belong has not been determined. Mr. Holt cut sections of the spines in situ, and found that they consisted of a knob of periotic cartilage passing into a mass of undifferentiated cells, the whole forming the core of a dermal spine consisting of hyaline ossified tissue. In my specimens I observed a third spine, much smaller, situated in the region of the frontal bone, behind and above the eye; it was visible in both the stages.

In Situ Ellipsometric Monitoring of Low Temperature Growth of Poly-Si Films By RF Plasma CVD

1994 ◽  
Vol 336 ◽  
Author(s):  
T. Shirafuji ◽  
Y. Hayashi ◽  
K. Tachibana
Keyword(s):  
Film Growth ◽  
Etching Rate ◽  
Present Condition ◽  
Rf Discharge ◽  
Rf Plasma ◽  
Phase Reaction ◽  
Silicon Thin Film ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTIn situ ellipsometry has been applied for monitoring silicon-thin-film growth on a glass substrate in RF-discharge plasma of SiF4+SiH4 diluted with H2 (80%). Polycrystalline silicon films were obtained at substrate temperature of 300°C and RF power density of 500MW/cm2. Volumetric fraction of c-Si increased from 50 to 80% by increasing the SiF4/ (SiF4+SiH4) flow ratio from 0 to 0.5. The fraction of c-Si also increased to 63% by sequential repetition of deposition with SiH4/H2 and etching with SiF4. The etching rate of a-Si was less than that of c-Si. These results suggest that semi-preferential etching of a-Si enhances the increase of c-Si fraction. A gas-phase reaction simulation has suggested that the dominant deposition precursor is SiH3, and the etchant is F in the present condition.

scholarly journals Where are the Shipwrecks of the Zuiderzee? A new version of the Shipwreck Database Flevoland (3.0), based on spatial and archaeohistorical research into wreck sites in the province of Flevoland

2018 ◽  
Vol 60 ◽  
pp. 191
Author(s):  
Y.T. Van Popta ◽  
A.F.L. Van Holk
Keyword(s):  
Satellite Images ◽  
Heritage Management ◽  
Aerial Photographs ◽  
Present Condition ◽  
Drainage Ditches ◽  
Archaeological Heritage ◽  
Density Maps ◽  
Local Topography ◽  
Archaeological Heritage Management

For several decades, maritime archaeologists, state authorities and maritime-archaeological companies have worked with an outdated and inaccurate dataset (with regard to position and presence) concerning shipwrecks in part of the Zuiderzee region. The information about these wrecks was scattered over multiple databases (both analogue and digital), documenting different numbers of shipwrecks across Flevoland. In order to gain a clear and accurate overview of the shipwrecks that were discovered in the former Zuiderzee, the Shipwreck Database Flevoland (SDF) was compiled. The third version of this database is presented in this article and is mainly aimed at documenting the present condition of shipwreck sites (wrecks in situ, removed or unknown) and the accuracy of the coordinates that mark the location of the shipwreck (exact, approximate or unknown). The excavation documentation of the shipwrecks was used for retrieving accurate descriptions of wreck sites, although in most cases these descriptions referred to drainage ditches and other local topography that since have been removed or altered. Historical aerial photographs, LiDAR data and satellite images were used for tracing the course of lost but relevant drainage ditches and the exact locations of shipwrecks. Multiple wreck sites were discovered in the aerial photographs, in the form of crop- and soil-marks revealing either wrecks or former excavation trenches. These visible wreck sites correspond perfectly to the locations mentioned in the research reports and prove the accuracy and feasibility of the used methodology. The new version of the SDF therefore provides more accurate distribution and density maps of wreck sites in the province of Flevoland, which is of importance for spatial maritime archaeological research. Furthermore, the newinformation on the accuracy and presence/absence of shipwrecks can be used in archaeological heritage management. Only shipwrecks that are still present in the former seabed, and whose recorded location is reasonably accurate, can be effectively protected.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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