Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/305
W. Dover, W. Jones
A new sectioning technique has been successfully developed and used to determine the three-dimensional form of the initial fatigue crack in copper. As previously found, intrusions are the earliest form of damage detectable and it has been further shown that their extension is by the formation of tubular holes starting from the surface. This mode of failure is finally superseded by sub-surface irregular microcrack link-up of the slip-band zone cracks and the gross form of crack propagation known as stage II.
{"title":"The initiation of fatigue cracks in copper","authors":"W. Dover, W. Jones","doi":"10.1088/0508-3443/18/9/305","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/305","url":null,"abstract":"A new sectioning technique has been successfully developed and used to determine the three-dimensional form of the initial fatigue crack in copper. As previously found, intrusions are the earliest form of damage detectable and it has been further shown that their extension is by the formation of tubular holes starting from the surface. This mode of failure is finally superseded by sub-surface irregular microcrack link-up of the slip-band zone cracks and the gross form of crack propagation known as stage II.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"17 1","pages":"1257"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82037950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/312
P. Mukhopadhyay, A. Gupta, A. K. Barua
The thermal conductivity of H2-N2 and H2-CO2 mixtures has been measured from -15 to 200°C by using the thick-wire variant of the hot-wire method. The experimental values have been compared with those calculated from the Hirschfelder-Eucken formula. Although fairly satisfactory agreement between theory and experiment is obtained it appears that for a precise interpretation of the thermal conductivity of polyatomic gas mixtures a better representation of the cross-relaxation phenomena is necessary.
{"title":"Thermal conductivity of hydrogen-nitrogen and hydrogen-carbon-dioxide gas mixtures","authors":"P. Mukhopadhyay, A. Gupta, A. K. Barua","doi":"10.1088/0508-3443/18/9/312","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/312","url":null,"abstract":"The thermal conductivity of H2-N2 and H2-CO2 mixtures has been measured from -15 to 200°C by using the thick-wire variant of the hot-wire method. The experimental values have been compared with those calculated from the Hirschfelder-Eucken formula. Although fairly satisfactory agreement between theory and experiment is obtained it appears that for a precise interpretation of the thermal conductivity of polyatomic gas mixtures a better representation of the cross-relaxation phenomena is necessary.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"18 1","pages":"1301-1306"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86908085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/420
E. Attia
The variation of damping with temperature in A1-0?25 wt.% Fe revealed the presence of two relaxation processes in the temperature range 200-400?C. The strain amplitude dependence and the effect of quench treatment on the processes observed are reported.
{"title":"Internal friction in aluminium containing 0?25 wt.% iron","authors":"E. Attia","doi":"10.1088/0508-3443/18/9/420","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/420","url":null,"abstract":"The variation of damping with temperature in A1-0?25 wt.% Fe revealed the presence of two relaxation processes in the temperature range 200-400?C. The strain amplitude dependence and the effect of quench treatment on the processes observed are reported.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"43 1","pages":"1343-1344"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79249637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/311
K. Naylor, A. Guile
Previous experiments have shown that short arcs rotating between ringshaped electrodes in a radial magnetic field move at a speed which is controlled by aerodynamic drag on the arc column when the pressure is above 1-2 atm. For these conditions it is possible to calculate an effective average arc size (which includes a drag coefficient) transverse to the direction of motion. Measurements have been made which enable the change in this effective arc size due to (a) arc speed, (b) arc current, (c) inter-electrode spacing and (d) gas pressure to be estimated for arcs moving in argon at a pressure of 3 atm. These changes are shown for arc speeds up to 80 m sec-1, arc currents up to 700 A and for spacings up to 1 cm, and it is suggested that electrode material introduced by vapour jets may be a significant factor.
{"title":"The effective drag width of short moving arcs in argon","authors":"K. Naylor, A. Guile","doi":"10.1088/0508-3443/18/9/311","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/311","url":null,"abstract":"Previous experiments have shown that short arcs rotating between ringshaped electrodes in a radial magnetic field move at a speed which is controlled by aerodynamic drag on the arc column when the pressure is above 1-2 atm. For these conditions it is possible to calculate an effective average arc size (which includes a drag coefficient) transverse to the direction of motion. Measurements have been made which enable the change in this effective arc size due to (a) arc speed, (b) arc current, (c) inter-electrode spacing and (d) gas pressure to be estimated for arcs moving in argon at a pressure of 3 atm. These changes are shown for arc speeds up to 80 m sec-1, arc currents up to 700 A and for spacings up to 1 cm, and it is suggested that electrode material introduced by vapour jets may be a significant factor.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"12 1","pages":"1295-1300"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82529803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/419
S. L. Dahake
The optical energy gap has been measured for single-crystal samples of (HgTe)3-In2Te3 alloys in the range 10-75 mol.% In2Te3. The absorption edges indicate direct transitions at energies similar to those previously determined for polycrystalline samples. Photoconductivity has also been observed in the 50% alloy.
{"title":"Optical energy gap of (HgTe)3-In2Te3 alloys","authors":"S. L. Dahake","doi":"10.1088/0508-3443/18/9/419","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/419","url":null,"abstract":"The optical energy gap has been measured for single-crystal samples of (HgTe)3-In2Te3 alloys in the range 10-75 mol.% In2Te3. The absorption edges indicate direct transitions at energies similar to those previously determined for polycrystalline samples. Photoconductivity has also been observed in the 50% alloy.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"18 1","pages":"1340-1342"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87159407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/302
L. M. Rogers
A two-valence-band model and the theory of transport in semiconductors with non-parabolic bands have been used to explain the carrier concentration dependence of the room-temperature thermoelectric power and below-room-temperature Hall mobility of undoped and Na-doped PbTe. It was assumed that the scattering is by lattice acoustical phonons. First-order non-parabolicity of the principal valence band can account for the low thermoelectric power of high carrier density material. The Hall mobility has been explained without having unusual temperature and carrier-concentration-dependent effective masses. Band parameters of the simple model were calculated.
{"title":"The Hall mobility and thermoelectric power of p-type lead telluride","authors":"L. M. Rogers","doi":"10.1088/0508-3443/18/9/302","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/302","url":null,"abstract":"A two-valence-band model and the theory of transport in semiconductors with non-parabolic bands have been used to explain the carrier concentration dependence of the room-temperature thermoelectric power and below-room-temperature Hall mobility of undoped and Na-doped PbTe. It was assumed that the scattering is by lattice acoustical phonons. First-order non-parabolicity of the principal valence band can account for the low thermoelectric power of high carrier density material. The Hall mobility has been explained without having unusual temperature and carrier-concentration-dependent effective masses. Band parameters of the simple model were calculated.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"4 1","pages":"1227-1235"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84360369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/313
P. Mukhopadhyay, A. K. Barua
The thermal conductivities of N2-Ar and O2-Ar mixtures have been measured over the temperature range from -183 to 200°c by the hot-wire method. The thermal conductivity against composition curves show a minimum at all temperatures which cannot be explained by the existing theories of heat conductivity. The results confirm the suggestion put forward previously by Mukhopadhyay and Barua in order to explain the similar appearance of a minimum for the H2-He system.
{"title":"Thermal conductivities of nitrogen-argon and oxygen-argon gas mixtures","authors":"P. Mukhopadhyay, A. K. Barua","doi":"10.1088/0508-3443/18/9/313","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/313","url":null,"abstract":"The thermal conductivities of N2-Ar and O2-Ar mixtures have been measured over the temperature range from -183 to 200°c by the hot-wire method. The thermal conductivity against composition curves show a minimum at all temperatures which cannot be explained by the existing theories of heat conductivity. The results confirm the suggestion put forward previously by Mukhopadhyay and Barua in order to explain the similar appearance of a minimum for the H2-He system.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"286 1","pages":"1307-1310"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90383020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/316
G. W. Hepplestone, P. Lewis
Measurements of the efficiency factor K under rigorously controlled experimental conditions are reported for nine monodisperse suspensions of latex spheres in water for the wavelength range in air from 0?38 to 0?63 ?m. These show good agreement in the range x = 0-30 with Irvine's computations from Mie's theory for m = 1?2, but the effect of optical dispersion on the (K, x) curve is significant. Secondary oscillation (ripple) has been detected in the K value for x values in the range 25-28.
{"title":"Light transmission measurements on suspensions","authors":"G. W. Hepplestone, P. Lewis","doi":"10.1088/0508-3443/18/9/316","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/316","url":null,"abstract":"Measurements of the efficiency factor K under rigorously controlled experimental conditions are reported for nine monodisperse suspensions of latex spheres in water for the wavelength range in air from 0?38 to 0?63 ?m. These show good agreement in the range x = 0-30 with Irvine's computations from Mie's theory for m = 1?2, but the effect of optical dispersion on the (K, x) curve is significant. Secondary oscillation (ripple) has been detected in the K value for x values in the range 25-28.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"11 1","pages":"1321-1325"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76978352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/314
R. Arridge
Measurements of the sign and magnitude of charges produced on threads of nylon 66 by contact with a variety of metals have been correlated with the contact potentials of the metals, measured against a gold reference electrode. These correlations suggest that nylon possesses a contact potential of about 42 v. A hydrocarbon polymer (polypropylene) exhibited a much higher contact potential, suggesting that the value for the polyamide is determined primarily by the properties of the amide group. Further evidence supporting this view is provided by experiments on charge diffusion which demonstrate that diffusion is faster across the molecular chain axes than along them, i.e. parallel to the amide-amide secondary linkages rather than parallel to the primary molecular backbone.
{"title":"The static electrification of nylon 66","authors":"R. Arridge","doi":"10.1088/0508-3443/18/9/314","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/314","url":null,"abstract":"Measurements of the sign and magnitude of charges produced on threads of nylon 66 by contact with a variety of metals have been correlated with the contact potentials of the metals, measured against a gold reference electrode. These correlations suggest that nylon possesses a contact potential of about 42 v. A hydrocarbon polymer (polypropylene) exhibited a much higher contact potential, suggesting that the value for the polyamide is determined primarily by the properties of the amide group. Further evidence supporting this view is provided by experiments on charge diffusion which demonstrate that diffusion is faster across the molecular chain axes than along them, i.e. parallel to the amide-amide secondary linkages rather than parallel to the primary molecular backbone.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"16 1","pages":"1311-1316"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82374810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-09-01DOI: 10.1088/0508-3443/18/9/421
B. Smith
The breadth of an x-ray diffraction line has been calculated for a grain having a finite absorption coefficient and divided by reflecting planes into parallel crystallite slabs whose thickness varies in a non-random manner with depth below the surface. The predicted `apparent' crystallite size is a function of the Bragg angle θ. Qualitative support is given to the theory by the results of x-ray and hardness measurements on lightly abraded nickel.
{"title":"The effect on X-ray line broadening of variation of crystallite size with depth below the specimen surface","authors":"B. Smith","doi":"10.1088/0508-3443/18/9/421","DOIUrl":"https://doi.org/10.1088/0508-3443/18/9/421","url":null,"abstract":"The breadth of an x-ray diffraction line has been calculated for a grain having a finite absorption coefficient and divided by reflecting planes into parallel crystallite slabs whose thickness varies in a non-random manner with depth below the surface. The predicted `apparent' crystallite size is a function of the Bragg angle θ. Qualitative support is given to the theory by the results of x-ray and hardness measurements on lightly abraded nickel.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"16 1","pages":"1345-1349"},"PeriodicalIF":0.0,"publicationDate":"1967-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86501441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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