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A case of localized anterior tooth surface loss (TSL) with an unusual aetiology is reported. Whilst suffering from a bout of acute depression and anxiety, a 29-year-old female caused significant trauma to her anterior dentition with a pair of fabric scissors. The presentation and management of this case is described.Although tooth surface loss is a common clinical finding in many patient groups, practitioners should be aware of possible unusual aetiologies which may be involved.

OBJECTIVES Professional tooth cleaning (PTC) may lead to loss of exposed dentin. The aim of the present study was to determine the absolute loss of dentin during PTC using various product combinations with an in vitro model. MATERIAL AND METHODS Dentin specimens (72) were randomly assigned to nine groups. In four groups each, prophy brushes and prophy cups were used in combination with four different abrasives (calcium pyrophosphate, pumice, Hawe cleanic, Nupro coarse). In the ninth group, a rubber cup with embedded fluoride and abrasives was used (pasteless prophy cup). The treatment time was 37 s. Surface loss was determined by profilometry. RESULTS The surface loss in the nine groups was as following: (1) brush/calcium pyrophosphate: 6.18 microm (a); (2) brush/pumice: 5.51 microm; (3) brush/Nupro coarse: 10.10 microm (b); (4) brush/Hawe cleanic: 1.88 (a, b); (5) prophy cup/calcium pyrophosphate 2.07 (c); (6) prophy cup/pumice: 6.07 microm; (7) prophy cup/Nupro coarse: 5.93 microm (c); (8) prophy cup/Hawe cleanic: 4.93 microm (c); (9) pasteless prophy cup: 11.86 microm (c). Groups with the same letter in parentheses are statistically significant different at p

OBJECTIVE: To evaluate the enamel erosive potential of modified acidic soft drinks under controlled conditions in an artificial mouth. MATERIALS AND METHODS: From each of 144 bovine incisors one enamel sample was prepared. Labial surfaces of the samples were ground flat, polished and covered with adhesive tape, leaving an exposed area. The samples were distributed among four (A‐D) groups for treatment with A: Coca-Cola, B: Sprite; C: Sprite light, D: orange juice. Either 1.0 mmol l )1 calcium (Ca) or a combination (comb.) of 0.5 mmol l )1 calcium plus 0.5 mmol l )1 phosphate plus 0.031 mmol l )1 fluoride was added to the beverages. Samples of each group were subdivided into three subgroups (-original; -Ca and -comb.) for treatment with original and modified drinks. De- and remineralization cycles were based on a standard protocol described earlier. Surface loss of the specimens was determined using profilometry after test procedure. RESULTS: In all subgroups, loss of enamel was observed. The enamel loss recorded for the samples rinsed with original Sprite and original orange juice was significantly higher compared with all other solutions (P ¼ 0.001). Lowest enamel loss was recorded for the original CocaCola group (P ¼ 0.001). With the exception of CocaCola, demineralization with the modified beverages led to significantly lower losses compared with the respective original solutions. CONCLUSION: Modification of the test soft drinks with low concentrations of calcium or a combination of calcium, phosphate and fluoride may exert a significant protective potential with respect to dental erosion. Oral Diseases (2005) 11, 7–12

This paper presents results of parallel wearing investigation of mass, surface, blade with 8 ploughshares after 224 ha of ploughed soil. Ploughshares were mounted on fivefurrow reversible plough of the firm Vogel&noot. Average per cent surface loss og the plougshares with narrov top was 13.47% and 10.70% on the plougshares with wide top. Average per cent surface loss of blades at examined plougshares after 28 ha of ploughed soil was 20.18% and 20.14%.Average mass was 39.91% (narow top) and 34.7% (wide top) while average per cent blades mass loss was 38.98% (narow top) and 38.98% (wide top).

SRTC investigated several options to remediate the contents of Tank 48H. Three options were examined: the Fenton reaction, Hydrolysis and Catalysis. Each option was investigated using a series of six reactions. These reactions were exploratory in nature; optimization is planned for a later date. Each experiment was conducted over a two-week period. The results of the experiments indicate that each process is a viable in-tank option, but there are limitations (discussed below) that must be addressed. For all three options, tetraphenylborate destruction (i.e., conversion of TPB into any other species) efficiencies proved higher at pH 7-8 than 11. However, parallel studies show that the corrosion rate for any in-tank option increases as pH decreases. TBP destruction efficiency (i.e., percent conversion of TPB into other species) at pH 11 for the Fenton reactions ranged between 22 per cent (600 mg/L TAML, 45 degrees C, 30 mL H2O2) to 68 per cent (100 mg/L TAML, 45 degrees C, 264 mL H 2O2). TBP destruction efficiency at pH 11, 45 degrees C for the hydrolysis reaction measured 84 per cent. TBP destruction efficiency at pH 11, 45 degrees C for the 1000 ppm Pd-catalysis reaction equaled 56 per cent. The TPB destruction efficiencymore » was highest for hydrolysis, followed by catalysis, and finally the Fenton reactions. The catalysis and hydrolysis experiments included placement of corrosion coupons in the reaction vessel. Only a small quantity of surface loss occurred (less than10 mils per year).« less

This investigation was conducted in an attempt to clarify the role of the organic matrix in bovine dentine demineralisation by 1% citric acid. Dentine slabs (n = 15) were treated for 2 min with 10% sodium hypochlorite (NaOCl, a strong protein solvent), 2% glutaraldehyde (GDA, a protein fixative) or deionised water (DIW, as negative control) prior to each of 5 demineralisation periods of 30 min. The mineral loss (ΔZ), lesion depth (LD) and surface loss (SL) were determined after each period of demineralisation, by transverse microradiography. The NaOCl-treated group showed higher ΔZ and LD than the GDA- and DIW-treated groups. No differences between GDA and DIW groups were found. The ΔZ and LD profiles were explained by quadratic fits (r2 >0.80; p = 0.001) in all groups. SL was detected only in the NaOCl-treated group. The data suggested that the maintenance of the organic matrix in the lesion might be important to reduce the erosion progression rate.

We have reinvestigated the Si $2p$ photoemission spectra of a clean $\mathrm{Si}(001)c(4\ifmmode\times\else\texttimes\fi{}2)$ surface with an apparently higher resolution than previous studies. A systematic and extensive line-shape analysis of the spectra taken at various photon energies and emission angles indicates that the Si $2p$ spectra are composed of seven different components. With regard to the recent debate on the Si $2p$ component of the down-dimer atoms, we conclude that even with the present resolution the corresponding surface core-level shift (SCLS) cannot be determined accurately but is in the range of 30--130 meV between the bulk and the second-layer components. One of the two newly identified components, with a SCLS of 1.4 eV, is interpreted as a surface loss structure due to the interband transition between surface-state bands.

The attenuation of low-frequency sound in the sea increases with pH. In most ocean areas, the value of pH changes significantly with depth, and must be included in an accurate attenuation computation. Previous determinations of other parameters, such as surface loss, which were based on older attenuation formulas, are therefore inaccurate. An analysis of a previously reported surface loss formula indicates that the predicted values are too high. >

Direct loss measurements for the heterogeneous reaction of the silyl radical, SiH 3 , obtained in a discharge flow reactor with mass spectrometric detection, are reported. From these measurements and the calculated gas-surface collision frequency, total surface loss coefficients, β, are determined for silyl on two different surfaces, one coated with a growing silicon-containing film and the other coated with Halocarbon wax

Wear as a surface loss of substance resulted from friction is considered in connection with various factors affecting tribosystem. These factors, first of all deformation and adhesion, are shown to be dependent on a scale factor as a result of combined effect of surface topography and material properties. The main trends in development of wear testing techniques, data collection, processing and presentation are discussed. Problems of test data reproducibility and comparability are shown to be very important and the attempts to solve these problems are examined. Scale factor in wear measurements is discussed. Concept of wear monitoring and its main purposes are considered in the context of providing non-failure, long-term operation at optimum friction performance of a tribosystem. Wear monitoring tools based on analysis of debris accumulation in a lubricated machine are reviewed.

The behavior of CF2 radicals was studied as a function of the temperature of the wall of the cylindrical cathode in dc-pulsed CF4 hollow cathode discharge plasma. Laserinduced fluorescence was used to examine the temporal behavior and radial distribution of CF2 radical density. The CF2 radical density increased about six times in magnitude by changing the wall temperature between 22°C and 100°C. The surface loss probability for CF2 radicals was estimated from the radial distribution of the CF2 radical density in the active plasma. The results show that the increase of the CF2 radical density in the heated wall can be interpreted as a decrease in the surface loss probability of CF2 radicals.

The surface loss function in the HREELS dipole scattering cross-section is calculated for Si(001)-(2×1)H and D surfaces using first-principles methods. Experimental spectra of these well-studied systems can only be explained if contributions from modes which induce polarization parallel to the surface are included. This relaxation of the surface dipole selection rule underlines the importance of first-principles calculations of vibrational spectral intensities at semiconductor surfaces.

We used hyperpolarized 129Xe NMR to measure pulmonary alveolar surface area per unit gas volume SA/Vgas, alveolar septal thickness h and capillary transit time ?, three critical determinants of the lung's primary role as a gas exchange organ. An analytical solution for a simplified diffusion model is described, together with a modification of the xenon transfer contrast imaging technique utilizing 90? radio-frequency pulses applied to the dissolved phase, rather than traditional 180? pulses. With this approach, three-dimensional (3D) maps of SA/Vgas were obtained. We measured global SA/Vgas, h and ? in four normal subjects, two subjects with mild interstitial lung disease (ILD) and two subjects with mild chronic obstructive pulmonary disease (COPD). In normals, SA/Vgas decreased with increasing lung volume from ~320 to 80?cm?1; both h~13??m and ?~1.5?s were relatively constant. For the two ILD subjects, h was, respectively, 36 and 97% larger than normal, quantifying an increased gas/blood tissue barrier; SA/Vgas and ? were normal. The two COPD subjects had SA/Vgas values ~25% that of normals, quantifying septal surface loss in emphysema; h and ? were normal. These are the first noninvasive, non-radiation-based, quantitative measurements of h and ? in patients with pulmonary disease.

This paper describes the use of time-resolved infrared radiometry (TRIR) to identify characteristic temperature-time signatures resulting from different subsurface thermal structures in aging aircraft. Central to the TRIR technique is the analysis of the temperature- time signatures at various locations as a step heating pulse is applied to the structure. Of particular interest is determining whether a signature can be identified which discriminates the presence of corrosion product from the simple thinning of the aircraft skin as might occur as a result of a previous repair. A technique is proposed which implements both area and localized heating sources. The area heating source provides one-dimensional heating of the specimen and allows suspect areas to be rapidly detected. A localized heating source is then used to further characterize the suspect regions.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

– Longitudinal data of 50-yr-old men, followed for 10 yr, were analyzed to identify variables which may be associated with healthy tooth surface loss. Three types of longitudinal models were used, arriving at similar conclusions. Predictors of sound tooth surface loss with aging included pocket depth, mobility, and recession.

A semi‐empirical surface loss algorithm is presented which is comprised of a rough scattering component derived from theory and a term which represents low‐frequency, low angle loss from other mechanisms such as absorption and bubbles, based on a fit to measured data. A prediction of surface duct propagation using the semi‐empirical algorithm and a current Navy standard propagation model is compared to measured data.

The effect of inorganic and organic acid fumes on teeth was explored in a cross-sectional study using blind dental examinations. A sample of 180 workers from two factories was randomly drawn. Among the 169 workers who participated in the survey, 88 were exposed to acid fumes and 81 were controls. The percentage of inorganic acid workers with tooth surface loss was 63.2%, while that for the controls was 37.7% (P less than 0.005). The corresponding figures in the organic acid company were 50.0% and 14.3% (P less than 0.02). In both companies the acid workers had significantly more often teeth with surface loss in the maxilla than their controls (P less than 0.02). Both anteriors and posteriors were affected. On the basis of the findings. it can be concluded that acid fumes at work are strongly associated with tooth surface loss.

Upward-refracting sound speed profiles, such as surface ducts and most Arctic profiles, induce repeated scattering from a rough ocean surface. Propagation models that treat only surface loss will rarely give the right answer, because the lost energy is discarded from the problem rather than being redistributed into other propagating, small angles. In this paper we present a coupled mode approach which can potentially be implemented numerically into many such models to carry out such a redistribution of energy; we have done this for two range-dependent propagation models, ASTRAL and the parabolic equation model (PE). The coupled mode approach requires as inputs two functions of angle, a reflection coefficient and a scattering kernel. Obtaining these inputs from a particular scattering model, we compare propagation model results with measured Arctic data.

Objectives: To compare the effect of brushing versus dipping using three different concentrations of fluoridated toothpastes on enamel erosion in vitro using surface profilometry. Methods: In a randomised, blinded experiment six groups of seven enamel slabs each were cut and mounted into resin blocks, ground and checked for surface flatness using a scanning profilometer (Scantron Proscan 2000). Each slabs’ surface was covered with nail varnish except for a small window (1 x 2 mm). Each group was immersed under static conditions for 2 minutes, five times daily in fresh 200 ml aliquots of citric acid 0.3% (pH = 3.6). In addition, three groups were immersed in three different fluoridated toothpastes (0 ppm F, 1100 ppm F, or 1450 ppm F) twice daily morning and evening for 2 minutes each time. The other three groups were brushed using the same toothpastes twice daily for 2 minutes each time. The total cycling period lasted 16 days during which the slabs were incubated overnight and between erosive challenges in artificial saliva at 37oC. A 60-minute gap was left between daytime immersions. Before and after dipping in the erosive solutions the slabs were rinsed with de-ionised water. After the cycling period, the slabs were analysed with the scanning profilometer to measure the amount of surface loss at day 4, 8, 12, and 16. Results: Surface loss ± SD of enamel at day 16 caused by citric acid combined with dipping using non-fluoridated toothpaste was 61.19 ± 8.50 μm, 1100 ppm F was 43.44 ± 10.94 μm or 1450 ppm F was 34.98 ± 4.29 μm. Surface Loss ± SD of enamel at day 16 caused by citric acid combined with brushing using 0 ppm F, 1100 ppm F, or 1450 ppm F toothpastes was 75.62 ±10.64, 63.51 ± 5.27 and 48.94 ± 13.67 μm, respectively. Conclusion: Enamel erosion was increased significantly (CI 95%) using brushing with toothpastes compared to dipping. In addition, enamel erosion showed a dose-response to fluoridated toothpastes. Acknowledgment: This project was supported by GlaxoSmithKline.

The mechanical quality factor of a carbon dioxide laser-welded fiber was measured and compared to flame-welded fibers to determine the suitability of laser welding for attaching suspension fibers to test masses in precision experiments. The loss in the fiber was found to be limited primarily by thermoelastic damping and surface loss, rather than loss from the weld. This technique is attractive for the attachment of fused silica suspensions where low thermal noise and precision location of the weld are considered.

Empirically derived surface loss values are not obtained directly but are derived from propagation loss measurements that include at least two other components. Surface loss is determined by making assumptions with regard to spreading loss, volume attenuation (and bottom loss, if appropriate). Marsh and Schulkin [AVCO Marine Electronics Office Tech. Rep. (1962)] analyzed an extensive set of transmission loss data from surface duct propagation to obtain surface loss values. They assumed that attenuation was entirely due to magnesium sulfate and used the early Marsh–Schulkin [J. Brit. IRE 25, N6 (1963)] attenuation formula (Thorp, Mellen et al., and Francois Garrison attenuation formulas were not known at the time). Corrections to the Marsh–Schulkin surface loss data have been computed that account for the differences between the Marsh–Schulkin and Mellen et al. [NUSC TR 7293 (1983)] attenuation formulae. The revised values show less loss for all frequency‐wave‐height (F‐H) products. The Kuo [J. Acoust. Soc. Am. 36 (1964)] perturbation theory estimates of surface loss are shown to be in good agreement with the revised data at low F‐H products.

A series of propagation loss measurements over a single surface reflected path is analyzed using the pH‐dependent global attenuation model. Values of surface loss for the frequency range 10–2000 Hz were obtained at low sea state conditions. The results for incident angles between 10° and 24° were found to be very small and in general agreement with the work of Adlington [J. Acoust. Soc. Am. 35, 1834–1835 (1963)]. A comparison is made to presently used surface loss models. [Work supported by NUSC.]

Measurements of NO2, HNO3, and PAN, as well as O3 were made in March 1985 at Alert, N.W.T., Canada. The observations show that PAN is by far the dominant NOy species at this Northern location at the onset of spring. Surface loss of HNO3 and possibly O3 seemed to occur over the snowy surface, but no loss of PAN was apparent. The observations are further evidence for the importance of PAN as a major carrier of the oxides of nitrogen in the clean troposphere. Although concurrently measured light hydrocarbons would appear to be sufficient for local formation of PAN, it is suggested that this did not take place but rather that long range transport from more southerly regions was responsible for the observed PAN levels.

The mechanism of reaction of atomic hydrogen with CH3Br has been examined by product analysis in a static system. In a vessel coated with NaOH to remove HBr, quantum yield close to unity are found for C2H6 formation. H + CH3Br → CH3 + HBr, 2CH3 → C2H6. The reaction scheme is modelled by assuming that surface loss is diffusion controlled. The step H + CH3Br → CH4 + Br accounts for less than 5% of the total reaction.

Whole body surface losses of zinc, copper, and iron were measured in 13 male volunteers who lived in a controlled environment for 4 to 9 months. For 88 daily samples, the mean losses for zinc, copper, and iron were 0.50, 0.34, and 0.33 mg/day (3.9, 26, and 2.1% of the mean dietary intakes, respectively). There was a large variance in metal losses with no significant differences in variance within-versus-between subjects or on the same-versus-different diets. The surface losses of zinc and iron increased the apparent dietary requirements determined by balance measurements only 5 and 3%, respectively, while the increase in copper requirement due to surface loss was 25 to 30%.

Thin layer surface activation is a technique in which the surface layers of a material are made radioactive by high energy charged particle bombardment. The resulting activity distribution as a function of depth within the surface is well defined, and consequently measurement of the activity loss from the material provides a means of monitoring any surface loss which has occurred. The application of this technique to the measurement of erosion-corrosion losses from mild steel specimens under boiler feedwater conditions is described, and further possibilities for its application are discussed.

THE linearized moisture flow equation is solved for two-dimensional line sources (buried or on the surface) with water extraction. Linearization is attained in the steady-state case by assuming the unsaturated hydraulic conductivity, K, is exponentially related to the pressure head, h, as K = K0 exp (ah). The water extraction is one-dimensional while the surface loss is proportional to exp (ah). As an aid for design or opera-tion, an algebraic relationship is presented giving the value of pressure head midway between lines for surface sources under steady conditions, with or without plant uptake. This form allows straightforward determination of pressure head using a calculator. As a further aid, nomographs relate pressure head midway between sources to rooting depth, source strength and uptake amount. The nomographs can be used directly without following through the theoretical developments. Distri-bution patterns of h for surface and subsurface sources are also given.

Radioiodinated metaiodobenzylguanidine (MIBG) has been shown to be extracted in the lung by an active, sodium-dependent, saturable transport system similar to that which extracts norepinephrine. Accordingly, first transit uptake of MIBG has been investigated as a method for in vivo evaluation of pulmonary biogenic amine metabolism. Issues that still must be resolved include the degree to which MIBG extraction is affected by simple loss of available vascular surface (in distinction to changes in amine metabolism). If MIBG lung extraction is altered by loss of pulmonary vascular surface alone, then a tracer must be found that can serve as a simultaneous monitor of vascular surface loss in order to allow normalization of the MIBG data. One tracer with such potential is radioiodinated iodoamphetamine (IMP). Accordingly, an experimental model of pulmonary vascular surface loss (lobar ligatures) was applied in an isolated-perfused lung model with simultaneous administration of MIBG and IMP. A linear relationship was found between MIBG extraction and percent lung surface loss by weight (n=21, r=0.75, P0.05). Addition of IMP (1 or 10 μM) to media containing MIBG (1 μM) (n=28) inhibited overall MIBG extraction, but decreases in MIBG uptake with vascular surface loss were otherwise parallel to those in experiments without IMP. IMP, however, did not adequately reflect vascular surface loss at the concentrations used in this study (extraction of IMP 1 μM=31.2±12.9% in control vs 32.7%±7.7% with greater than 50% lung surface loss, n=18, P=NS). The results indicate that a correction for vascular surface loss is needed to interpret MIBG results in vivo, but suggest that IMP is not able to serve this purpose.

The temperature (T) dependence of the absorption coefficient β at 10.6 μm of Czochralski‐grown high‐resistivity GaAs and chemical vapor deposited (CVD) ZnSe is measured by laser calorimetry. Experimental data are compared with theoretical curves for intrinsic multiphonon absorption. The temperature dependence of β for GaAs is found to possibly exhibit multiphononlike behavior below ∼450°K, but deviates rapidly from theoretical predictions above ∼500°K. The latter effect may be attributed to an increase in free‐carrier density via thermal ionization from a level near 0.37 eV. The absorption coefficient of CVD ZnSe is found to be independent of T over the temperature range investigated, and therefore this material appears to be impurity or surface loss dominated.

The grain-boundaries/surfaces play a vital role in the mechanical and electronic properties of a material. The importance of understanding their structure, therefore, cannot be overstressed. In a scanning transmission electron microscope, electron energy loss spectroscopy has long been used to study the electronic structure of the bulk material of a specimen while various efforts have been made to suppress the contribution to the spectrum from the surface electronic excitations. However, in this paper we demonstrate the possibility of extracting this surface loss component so as to obtain electronic structural information from the grain-boundaries/surfaces. This technique is applied to specimens of fresh and aged polycrystalline Pd films as well as a hydrogen-charged PdH polycrystalline film.

Many disadvantages of the self-curing acrylic resin restoration have been corrected by an improved technique of cavity preparation, insertion, finishing, and polishing. In a clinical test, acrylic resin surpassed the silicate cement in the significant qualities of discoloration, surface loss, fracture, adaptation, recurrent caries, and pulp injury. Marginal adaptation was superior in the silicate cement restorations. The present advantages of acrylic resin broaden the indications for use. The brush-on method permits insertion of several restorations simultaneously. This study establishes that, although acrylic resin does not fulfill all the requirements of an ideal restorative material, it offers more advantages than the silicate cement.

A theory is presented of the scattering of underwater sound by the sea surface. The Neumann‐Pierson oceanographic model of the sea is used. These developments are applied to propagation in an isothermal surface‐bounded channel. A theoretical curve is presented of surface loss vs the rms wave height and frequency product at the lower end of the curve.

Characteristic electron energy loss spectra of layered films of Bi-Mg have been measured and a new loss has been found at 12.9 ± 0.2 eV. This loss can be interpreted as a surface plasma loss at the metal-metal interface. A surface loss in Al-Mg films was not reproducible, but a new loss was observed at 26.4 eV which can be interpreted as a single Al loss (15.4 eV) plus a single Mg loss (10.9 eV).

The normal incidence reflectance of an electron-gun-evaporated Rh film measured over the photon energy range 0.5 ≦ ħ ω ≦ 11.7 eV is presented. The optical functions ϵ1(ω), ϵ2(ω), σ(ω), and the volume and surface loss functions have been calculated by a Kramers-Kronig analysis of the appropriately extrapolated reflectance data. The structure in the optical conductivity σ(ω) at 1.1, 2.5, and 5.6 eV is compared to the predictions of a recent band structure calculation; the optical transitions giving rise to this structure are discussed. The volume and surface loss functions, which have peaks at 8.8 and 8.1 eV, respectively, are compared to characteristic electron energy loss measurements.

Reflectance measurements for Ge films evaporated in situ are reported for 16 wavelengths between 490 and 1610 \AA{}, corresponding to photon energies of 25.2 and 7.7 eV. Measurements were taken after 3-min exposures to ambient pressures of 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}7}$ Torr. Reflectance values at a number of angles of incidence were used to compute the optical constants: the refraction index $n$, the extinction coefficient $k$, and the real and imaginary parts of the frequency-dependent dielectric constant $\ensuremath{\epsilon}(\ensuremath{\omega})={\ensuremath{\epsilon}}_{1}+i{\ensuremath{\epsilon}}_{2}$. Values are also presented for the characteristic electron energy-loss functions, i.e., the volume loss, $\ensuremath{-}\mathrm{Im}{\ensuremath{\epsilon}}^{\ensuremath{-}1}$, and the surface loss, $\ensuremath{-}\mathrm{Im}{(\ensuremath{\epsilon}+1)}^{\ensuremath{-}1}$. The quantity $\ensuremath{-}\mathrm{Im}{\ensuremath{\epsilon}}^{\ensuremath{-}1}$ peaked at 16.1 eV and had a half-width of 3.9 eV. Electron oscillator strengths, summed between 8 and 25 eV, gave a $\ensuremath{\hbar}{\ensuremath{\omega}}_{p}$ value of 13.7 eV. The present data are in better agreement with the accepted plasma theory than are previous data. Some changes of optical characteristics caused by exposure to ambient pressures and air are presented.

A major sex difference in the rate of continuing bone expansion was confirmed for 5660 adult subjects of European ancestry. The five-decade gain in metacarpal midshaft area amounted to 8.4% in 3455 females and 2.8% in 2205 males. There was no systematic age effect on the length of the second metacarpal. Accordingly, both bone expansion and the marked sex difference in its magnitude may be attributed to sex-specific aspects of ageing much like the sex difference in endosteal surface loss.

The influence of work‐function reduction and variation of the incident‐beam angle on the secondary‐electron yield and secondary‐electron energy distribution from the (111) face of Ge have been studied. Reduction of the work function from 4.79 to 2.3 eV by deposition of Na increased the maximum yield from 1.2 to a value near 3.6, while the primary energy at which the maximum yield occurred increased from 700 to 2000 eV. The energy width of the slow secondary‐electron energy distribution function decreased strongly both with increasing primary energy and decreasing work function. An investigation of the energy of secondary electrons involved in the yield variation with incident beam angle suggests that this variation in yield is a direct result of variation in the primary‐electron backscattering coefficient. A bulk plasma loss of 16.7 eV is manifested in the total secondary‐electron energy distribution function by a series of peaks lying at multiples of 16.7 eV below the elastic peak. In addition, a shoulder on the first 16.7 eV loss peak indicates the existence of an 11 eV surface plasma loss. An overlayer of Na does not seriously affect the bulk plasma loss spectrum, but shifts the 11‐eV surface loss to about 13 eV and causes the appearance of a second 3.5‐eV surface loss peak.

An analysis has been carried out for obtaining the free- and bound-exciton lifetimes from optical phase shifts measured on crystals with surface loss. It is found that the bound-exciton lifetime can be obtained directly from the measured phase shifts associated with the free- and bound-exciton lines, regardless of the surface condition. The optical phase shift of the free-exciton line from a "surface-free" crystal should be larger than that measured on the same crystal but with a lossy surface. Experiments to measure the phase shifts of free excitons and excitons bound to neutral and ionized donors (${D}^{0}$ and ${D}^{+}$) and neutral acceptors (${A}^{0}$) have been carried out and the various lifetimes have been determined from the above analysis. It was found that ${\ensuremath{\tau}}_{{D}^{0}}=1.07\ifmmode\pm\else\textpm\fi{}0.1$ nsec, ${\ensuremath{\tau}}_{{D}^{+}}=0.8\ifmmode\pm\else\textpm\fi{}0.08$ nsec, and ${\ensuremath{\tau}}_{{A}^{0}}=1.6\ifmmode\pm\else\textpm\fi{}0.6$ nsec at 1.6 \ifmmode^\circ\else\textdegree\fi{}K. The free-exciton lifetime decreases with increasing impurity concentration in the material (the longest lifetime obtained being 2.9\ifmmode\pm\else\textpm\fi{}1.3 nsec), indicating that the decay of free excitons is not governed by the direct annihilation of the electron-hole pairs.

In this paper, the approximate equivalent circuit of the grooved solid pole synchronous motor is derived. In the approximate equivalent circuit, the upper part (grooved part) and the lower part (core part) of the grooved solid pole synchronous motor are separated. As the presence of the grooves on solid poles causes a part of the eddy current which is considered as an end effect problem, strictly theoretical solution of this problem is extremely difficult. In this paper, measured value of surface loss is described and studied by considering the end effect, and the surface loss reduction factor is also obtained. This grooving technique is used for the solid pole synchronous motor and for the claw pole machine.

We have explored numerically the effects on soliton propagation of a third order damping term in the modified sine-Gordon equation. In Josephson tunnel junctions such a term corresponds physically to quasiparticle losses within the metal electrodes of the junction. We find that this loss term plays the dominant role in determining the shape and stability of the soliton at high velocity. Applied Physics Letters is copyrighted by The American Institute of Physics.

Although high output power density can be achieved in electrical machines by increasing airgap flux density, this also increases tooth ripple flux density with a subsequent increase in pole surface loss. This loss, however, can be reduced with magnetic wedges. This paper describes the calculation of pole surface losses and ripple flux density, and the effect of magnetic wedges on the characteristics of practical motors is shown experimentally.

Two visible light-cured composite resins, Ful-Fil and X-55, were used to restore 136 Class I and Class II cavity preparations in adult teeth. After 5 years the ratings for color matching, interfacial staining, secondary caries, and marginal adaptation remained good, using USPHS criteria (ranging from 75% to 100% Alfa). The average surface loss due to occlusal wear was 158 and 169 micrometers for Ful-Fil and X-55, respectively. Significant differences in occlusal wear were noted depending on tooth and restoration type. These results indicate that both composite resins meet the current ADA Council on Dental Materials specifications for full acceptance in adult posterior teeth.

Whole-body sweat losses of zinc were studied in men during three separate studies on the effects of marginal intake of zinc. Zinc lost via the sweat appeared to be directly related to dietary zinc intake. Whole body zinc losses of an average of 0.49 mg/day were observed in the men during the control period when zinc intakes averaged 8.3 mg/day. On the other hand, when zinc intakes were 3.6 mg/day, whole body surface zinc losses were substantially lower, averaging 0.24 mg/day in two of the studies and slightly lower than control values in the third study. A loss of 0.62 mg of zinc/day was observed when 33.7 mg of zinc was fed. These losses reduced apparent balances by 12 to 84% and need to be considered when evaluating zinc retention. When men were eating the diets with marginal levels of zinc (3.6 mg/day), zinc losses in sweat gradually declined with time. This suggested a homeostatic mechanism to conserve zinc during periods of depletion.

Two visible light-cured composite resins, Ful-Fil and X-55, were used to restore 136 Class I and Class II cavity preparations in adult teeth. After three years, the ratings for color matching, interfacial staining, secondary caries, and marginal adaptation remained good using USPHS criteria (ranging from 72% to 100% Alfa). The average surface loss due to occlusal wear was 145 and 164 micrometers for Ful-Fil and X-55, respectively. These results indicate that Ful-Fil composite resin meets the current ADA Council on Dental Materials specifications for provisional acceptance in adult posterior teeth.

In this paper we show several analytical approaches to study the effect of dissipation on fluxon motion; our attention is mainly devoted to the surface impedance term which is the main quantity responsible for qualitative dynamical changes in the junction.

Direct observation is reported of fluxon reflections in a Josephson transmission line (JTL) using a Josephson sampler. It is found that a single fluxon, an antifluxon, and multi-antifluxons are reflected depending on the bias current at the end of the JTL. The observed reflection properties, including the interaction between reflected antifluxons, can be satisfactorily explained by numerical simulations taking account of the nonlinear shunting loss and the surface loss.

Determination if surface loss and bottom loss from at‐sea measurements requires the assumption of a propagation loss model. In most cases, this has consisted of a simple spreading loss (spherical and cylindrical) model plus attenuation. The recent development of a pH‐dependent attenutation formula will have an impact on previously reported values of loss that were obtained using the old Marsh‐Schulkin or Thorp attentuation formulas. Due to the depth dependence of a typical pH profile, this impact will depend on the configuration of the measurement in the water column. For example, previous values of surface loss that were obtained from propagation loss measurements in a surface duct (where the pH and, hence, the attenuation have the highest values) will be too high since the previously assumed value of attenuation was too low. Estimates are made of the possible impact on some of the most widely used formulas. [Work supported by NUSC.]