Short Hole Research Articles

Woodwind instrument tone hole impedances

Open or closed tone holes are usually represented as shunt impedances in the air column transmission line equations. Nederveen and van Wulfften Pathe (1963) pointed out that the lumped circuit for a closed tone hole includes a negative inertance in series with the shunt compliance. The open and closed tone hole impedance parameters have been calculated as a function of frequency for various tone hole proportions using variational method, and experimentally confirmed in detail. Large diameter short chimney holes (as on the sax) behave differently from small diameter long chimney holes (e.g., clarinet). Additional viscous and thermal losses near the sax-type open holes lessen their otherwise higher radiation efficiency. A single sax-type open hole at a pressure node radiates as a dipole while clarinet-type holes do not, since the evanescent modes are more weakly generated at the main bore-tone hole junction and more rapidly attenuated in the long chimney. The series impedance for an open hole, like the closed hole, is a negative inertance larger in magnitude than for the closed hole. The behavior of an open hole lattice near its cutoff frequency differs for the two types of holes. Adjacent open or closed sax holes interact within the main bore, while clarinet holes do not. External interaction via radiation from adjacent open holes raises the shunt inertance by a few per cent. Internal and external hole interactions modify overall instrument tuning and radiation efficiency. [Work supported by NSF.]

Electron and Hole Drift Mobilities in GeSe2 Glass

physica status solidi (a)Volume 54, Issue 2 p. K159-K161 Short Note Electron and Hole Drift Mobilities in GeSe2 Glass L. Tóth, L. Tóth Central Research Institute for Physics, Hungarian Academy of Sciences, Budapest Search for more papers by this author L. Tóth, L. Tóth Central Research Institute for Physics, Hungarian Academy of Sciences, Budapest Search for more papers by this author First published: 16 August 1979 https://doi.org/10.1002/pssa.2210540262Citations: 4 P.O.B. 49, H-1525 Budapest, Hungary. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume54, Issue216 August 1979Pages K159-K161 RelatedInformation

Photoemission from transition metal surfaces

Photoemission spectra for nickel are contrasted with those for copper. The differences noted are largely attributable to the short hole lifetimes in nickel-a consequence of the Fermi level falling within the band.

Charge Migration Phenomena in γ-Irradiated Costacking Complexes of DNA Nucleotides: I. A Computer-Assisted ESR Analysis of dAMP · dTMP Complexes in Frozen Solution

Following earlier studies on the γ radiolysis of dAMP and dTMP in frozen aqueous solution, several dAMP.dTMP costacking complexes, at different [dAMP]:[dTMP] molar ratios, have now been investigated using the same computer assisted technique. The purpose of this investigation was to determine whether single radical reaction kinetics proceed in these complexes in the same way as in the individual constituents when irradiated separately, or whether intermolecular spin transfer phenomena take place. This work embodies two interrelated parts. The first part deals with radical populations induced in the dAMP.dTMP complexes by photosensitization, these being essentially radical anions and their conversion products, H addition radicals. The second part deals with the more complex populations induced by γ rays. With γ rays, the simultaneous presence of both the anionic and the cationic kinetics makes the ESR results rather involved and application of the computer technique becomes imperative. In both cases one prominent fact was discovered. When dAMP is allowed to interact by stacking with dTMP, H-addition radicals on dAMP are never formed, even when [dAMP]:[dTMP] molar ratios are as high as 10:1. Conversely, the relative concentrations of H-addition radicals on dTMP are increased by corresponding factors. This is likely to be due to long range electron transfer phenomena involving adenine anions and intact thymine molecules: A-T → AT-. Additionally, the existence of a short range hole transfer mechanism was also detected: AT+ → A+T. The presence of a stacking conformation in the complexes is a necessary condition for these charge migration phenomena to occur. Indeed, when the constituent molecules are dispersed in a glassy matrix, the overall radical population is simply the sum of the radical populations formed in dAMP and dTMP when irradiated separately.

Continental drilling

Continental Drilling, a 56‐page report of the Workshop on Continental Drilling at Ghost Ranch, Abiquiu, New Mexico, June 10–13, 1974, has been published by the Carnegie Institution of Washington. The workshop was convened to prepare a report for submission to the U.S. Geodynamics Committee in response to one of the committee's initial priorities in the U.S. program for the Geodynamics Project: to investigate the contribution that could be made by land drilling to resolve major problems of geodynamics. The report recommends a continental drilling program calling for an extensive application of short holes (30–300 m) and the selective application of a few intermediate to deep holes (300–9000 m).The report recommends a continental drilling program calling for an extensive application of short holes (30–300 m) and the selective application of a few intermediate to deep holes (300–9000 m).

Improvements in stope drilling and blasting for deep gold mines : White, AJ Joughin, NC Cook, NG 8F, 6R J.S. African Inst. Min. Metall. V75, N6, Jan. 1975, P139–150

The rate of face advance in the gold mines is between 3 and 10 m a month, with a median value of about 5 m a month; it follows that faces are blasted less frequently than is planned. There are many advantages in the use of short holes for stoping to give face advances of from 0,7 to 0,8 m per blast. This has the potential for so increasing the frequency of blasting that monthly rates of face advance could be improved significantly. Cleaning with face scrapers is too slow to permit the maximum achievement of a complete clean, drill, and blast cycle for each shift. Short-hole blasting, combined with the use of mechanical conveyors for face cleaning, offers the possibility of completing two such cycles each day, yielding monthly rates of face advance of up to 35 m. Experiments aimed at developing safe, unitized explosive charges well-suited to produce reliable face advances of 0,7 to 0,8 m per blast under a wide range of gold-mining conditions have been notably successful. A novel method of assessing the effectiveness of a blast based on the percentage of holes that leave socket lengths of 5 cm or less was used. . Unitized charges of 60 per cent Ammon gelignite, 600 mm long by 25 mm in diameter, appear to be near optimal. The explosive is de-sensitized to obviate detonation by chance mechanical impact, but requires only a 6D detonator for initiation; it has good water-resistance. Means have been developed for producing these cartridges automatically, but the necessary machines will have to be built specially and the cartridges are not yet available in large numbers. A second experiment by way of an extended pilot production trial using these cartridges in holes 0,9 m long is now under way. Preliminary results indicate that drilling and explosive efficiencies and productivity are well above average, even though face scraping is being used. Unitized charges of this type are likely to prove even more advantageous when mechanical face conveyors come into use.

Search techniques for zinc ore using computer simulation

Zinc ore exploration is generally undertaken through deep drilling in the area adjacent to the outcrop. Experience in one complex geological area suggests that, in that area, exploration might be more profitable if short holes were drilled to bedrock to locate the zinc ore body at the sub-outcrop (the interface between bedrock and the soil and glacier deposited cover). This problem is evaluated by assuming three logical shapes and sizes of ore body and selecting a method for drilling by utilizing a computer model to simulate drilling. The test results indicate that costs of using this proposed method of exploration are substantially less than the traditional approach of exploring for zinc ore and that probabilities of success can be predetermined.

Ein versuch der bestimmung des erdwärmeflusses in flachbohrungen

In 1968 the Institute of Geology and Geophysics of Siberian branch of the Academy of Sciences of the U.S.S.R. made the following geothermal study of nine drill holes of about 100 m depth. They were located in the southern part of the west Siberian lowland along the Ischim-Barabinsk profile. Temperature measurements in the drill holes were made using an electric resistance thermometer with a copper thermal element. Thermal conductivity of rocks was determined by the impulse method of the cylindrical probe in the field condition. The average value of the heat flow on the profile is equal to 0.96 μcal./cm 2 · sec. The data show that it is possible to determine the real values of the heat flow in short drill holes.

Hole Injection in Junctions between Amorphous Ge Layers and n‐Type Ge Single Crystals

physica status solidi (b)Volume 24, Issue 1 p. K17-K21 Short Note Hole Injection in Junctions between Amorphous Ge Layers and n-Type Ge Single Crystals R. Grigorovici, R. Grigorovici Institute of Physics of the Academy, BucharestSearch for more papers by this authorN. Croitoru, N. Croitoru Institute of Physics of the Academy, BucharestSearch for more papers by this authorL. Vescan, L. Vescan Institute of Physics of the Academy, BucharestSearch for more papers by this authorM. Marina, M. Marina Institute of Physics of the Academy, BucharestSearch for more papers by this author R. Grigorovici, R. Grigorovici Institute of Physics of the Academy, BucharestSearch for more papers by this authorN. Croitoru, N. Croitoru Institute of Physics of the Academy, BucharestSearch for more papers by this authorL. Vescan, L. Vescan Institute of Physics of the Academy, BucharestSearch for more papers by this authorM. Marina, M. Marina Institute of Physics of the Academy, BucharestSearch for more papers by this author First published: 1967 https://doi.org/10.1002/pssb.19670240145Citations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume24, Issue11967Pages K17-K21 RelatedInformation

The Effect of Spinneret Hole Length on Fiber Diameter; A Means for Measuring Polymer Solution Inhomogeneities

The single fibers from a multiple spinneret having holes of equal diameter but of different lengths may have considerably different diameters. suggesting the use of Poiseuille's formula for flow through capillary tubes to describe or predict the effect. A simple spinneret having four holes of equal diameter and known differing cylin drical hole lengths (10 times the sizes used for fiber sprinning) was built to test polymer solutions. The long hules extruded less material than the short holes for a homogeneous polymer solution or liquid The amount extruded from each hole was consistent with the amount calculated by Poiseuille's formula. However, when gelatinous masses were present in the polymer solution. Poiseuille's formula was no longer applicable, an increase in the material coming from the longer holes always being noted. This increase m percent material could be used as a test for the degree of solution inhomogeneity. When an inhomogeneous polymer solution was spun into fibers, the occurrence of thick-and-thin filaments was noticeable when different portions of the same fiber were examined in the vibroscope.

On the Torsion of the Thin-Walled Hollow Rectangular Bar with a Rectangular Hole on One Side

The authors have investigated the shearing stress on each side and the torsional angle in the thin-walled hollow rectangular bar with a hole of various sizes in a longer side subjected to torsion. The resu1ts obtained were as follow : (1) The meas shearing stress through the thickness calculated by the usual formula is far larger than the measured shearing stress in the case of short hole. (2) By combining Fig.3 or 4 with the calculated shearing stress, it has been found that the shearing stress of each side, having a hole of any size, can be obtained by caluculation. (3) The torsional angle steeply increases with the hole length. But in the case of short hole, the torsional angle hardly differs from that of the case without the hole.

堂屋敷鉱床東部硫化鉱体の長孔発破設計について

We have applied the long hole blasting to the mining method for low grade pyrite ore body. And we have succeeded in the application of block caving method to breaking pyrite ore body which was difficult to mine according to caving, collapse and underground water.The plan of long hole blasting is based upon a linear charge originated in short diameter long holes against the theory of a concentrated charge, therefore we have arranged the line of least resistance and spacing of holes adaptable for a linear charge without cushioning.At the plan of blasting of block caving method, perfect-fanshaped arrangement of holes by symmetrical drilling chambers was suitable for weak and brittle conditions of ore body from our results.

A Few More Mechanics' Tools

Brief descriptions with drawings are given of several useful tools, including a scribing block, mostly made in the lathe; a boring tool; a tool for boring a short hole to an accurate diametral size; a tool for milling a flat surface with a single-point-cutter; tools for turning portions of spheres; a toolmaker's vice with an extra jaw that can be removed at will; and a number of other small tools.

De Rijpingsvreterij van den Ooftboom-Spintkever, Scolytus Mali Bechst. (Col.: Scolyti Dae)

1. The maturation feeding ofScolytus mali Bechst. is described for the first time. 2. This feeding takes place at the base of the spurs (short-shoots) where a short hole is bored by the young beetle. 3. The damaged spurs whither and die, finally dropping to the ground. 4. The described infestation originated from a dead apple, pear and plum tree in the neighbourhood, the bark of which was heavily perforated by the emerging beetles. The breeding galleries are shortly described; attention is further drawn to the occurrence of numerous horizontal galleries the significance of which is not yet clear. 5. The parasites reared from the infested wood are enumerated. The most numerous is a Chalcid, subfam. Eulophinae, viz.Elachistus leucogramma Rtzb. but it occurred in a small percentage, perhaps 2–5%, only. 6. Removing and destroying all dead or dying fruit trees, which are infested by these Scolytids, is strougly advised.