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Large-scale molecular dynamics simulations are used to study strain and stress localization in atomistic polycrystalline FCC digital samples in a thin-film configuration, deformed in tension. Special focus is placed on the effects of additional grain boundary disorder on the dislocation–grain boundary interaction. The development of the localized stress and strain regions is studied as dislocations are emitted from and arrive at grain boundaries. Digital samples with two different degrees of disorder in the grain boundaries but otherwise identical microstructures are compared in order to understand the effects of additional defects on the stress concentration that develops at the grain boundaries. Localization phenomena are found to depend on the details of the grain boundary defect structure and relaxation state. The results clearly show that the samples with more disordered grain boundaries are more prone to strain and stress localization, with a higher fraction of atoms experiencing extreme deformation. The simulation results are validated by comparison with the predictions of continuum theories and experimental measurements of localized stress performed in austenitic stainless steel.

Localized deformation has emerged as a key factor in the crack initiation process for irradiated steels, as cracks are observed to nucleate preferentially at these sites. Using high resolution electron backscatter diffraction (HREBSD), the local stress tensor surrounding the dislocation channel-grain boundary interaction sites was quantified and coupled with fully determined grain boundary plane orientation information to determine, for the first time, the relationship between grain boundary normal stress and intergranular crack initiation in irradiated austenitic stainless steel. A Fe 13Cr 15Ni alloy was strained in simulated boiling water reactor, normal water chemistry after quantifying the residual stress tensor at discontinuous dislocation channel – grain boundary interaction sites where grain boundaries were determined to be well oriented with respect to the loading axis. Local stresses at the grain boundary were observed to reach magnitudes greater than 1.5 GPa at a distance of 200 nm from the intersection between the dislocation channel and the grain boundary. A pseudo-threshold stress of 0.9 GPa was measured, below which no cracking was observed. As the stress acting normal to the grain boundary increased above this value, the susceptibility to cracking increased with the cracking fraction reaching 100% at the high end of the stress range. This study shows for the first time that not only does intersection between discontinuous dislocation channels and grain boundaries result in peak local stresses, but the magnitude of the local tensile stress drives the crack initiation process.

A novel explanation based on the variation of grain boundary composition is proposed to elucidate the localized nature of irradiation-assisted stress corrosion cracking, i.e., intergranular cracking is observed only at specific sites of random high-angle grain boundaries, in a Fe-13Cr-15Ni austenitic model alloy subjected to proton irradiation and straining in a high-temperature water environment. Specifically, this work presents electron microscopy characterization of multiple cracked and un-cracked grain boundary sites and the neighboring oxides. The depletion of Cr and enrichment of Ni, as expected due to radiation-induced segregation, is observed at grain boundaries far from the crack tip (for cracked sites) or the metal surface (for un-cracked sites), and such modification of grain boundary composition is enhanced in the vicinity of the corrosion reaction front. Unexpectedly, grain boundary sites beyond the crack tip always present a lower Ni content and higher Cr content than the un-cracked sites on the same grain boundary. Overall, it is proposed that the site-specific susceptibility to stress corrosion cracking is governed by the grain boundary microchemistry, which determines not only the quantity of Cr, but also the efficiency of Cr transport to the reaction front and thus the protectiveness of the inner oxide. These effects of local composition may be further coupled with the local structure of and the local stresses interacting with the random high-angle grain boundaries.

Quantitative measurements of stress near dislocation channel–grain boundary (DC–GB) interaction sites were made using high resolution electron backscatter diffraction (HREBSD) and have been compared with molecular dynamics (MD) simulations. Tensile stress normal to the grain boundary was significantly elevated at discontinuous DC–GB intersections with peak magnitudes roughly an order of magnitude greater than at sites where slip transfer occurred. These results constitute the first measurement of stress amplification at DC–GB intersections and provide support to the theory that high normal stress at the grain boundary may be a key driver for the initiation of irradiation assisted stress corrosion cracks.

Ground granulated blast furnace slag (GGBFS) and steelmaking slag have been used as a raw material for cement production or as an aggregate to make concrete, which contribute aluminum, calcium, iron, and silicon oxides. The suitability of the slag for a particular application depends on its reactivity, cost, availability, and its influence on the properties of the resulting concrete. For the interest of durability studying of concrete in the presence of slag, the accelerated carbonation products and leaching behavior of the slag and Portland cement (PC) were studied. The experimental results confirmed that the slag was more resistant to carbonation compared to PC. The carbonation degree of GGBFS reduced by 17.74%; and the carbonation degrees of steelmaking slags reduced by 9.5%-11.94%. Carbonation neutralized the alkaline nature of the hydrated pastes and gave rise to the redox potential of the leachate slightly (30–77 mV). The carbonation also increased the release of most of the elements presented, except for calcium, to the aqueous environment. It is concluded that blend cements (PC plus slag) have economical advantages and better durability compared to PC.

Definitions et subdivisions du volume pulmonaire 17S48 Preparation du patient 17S49 Determination des subdivisions pulmonaires ........ 17S49 Mesure de la CRF par plethysmographie corporelle 17S50 Introduction et theorie 17S50 Materiel 17S50 Technique de mesure 17S50 Controle qualite 17S51 Calculs 17S52 Mesure de la CRF par rincage de l’azote 17S52 Introduction et theorie 17S52 Materiel 17S52 Technique de mesure 17S53 Controle qualite 17S53 Calculs 17S54 Mesure de la Crf par dilution de l’helium 17S54 Introduction et theorie 17S54 Materiel 17S54 Technique de mesure 17S55 Controle qualite 17S56 Calculs 17S56 Mesure des volumes pulmonaires par des techniques d’imagerie 17S56 Radiographies conventionnelles 17S57 Tomodensitometrie 17S57 Imagerie par resonance magnetique 17S57 Controverses et questions critiques 17S57 Valeurs de reference 17S58 Prevention des infections 17S58 Abreviations 17S58

Generalites 17S80 Spirometrie 17S81 Volumes pulmonaires 17S83 Capacite de diffusion du monoxyde de carbone 17S85 Les differents types d’anomalies respiratoires 17S86

Udgivelsesdato: 2007-Mar

A touch-screen controlled, robot-loading system for the Thomas Swan 7×2 flip-top showerhead reactor has been developed. The reactor has been configured for the growth of GaAs and InP materials and has been used to prepare strain-balanced MQW (SBMQW) pin solar cell material on GaAs substrates. Both material characterisation and solar cell performance for SBMQW pin cells are described.

A quantum well solar cell is a special multiple-band gap device with intermediate properties between heterojunction cells (sum of the currents generated in the different materials but voltage controlled by the lowest of the two band gaps) and tandem cells (sum of the voltages but current determined by the worst of the two sub-cells). Strain-balanced GaAsP/InGaAs multi-quantum wells move the absorption edge of GaAs solar cells closer to the optimum value for single junction cells with no need for any partially relaxed buffer layer to accommodate lattice mismatch between the absorbing layers and the substrate. Covering a large spectral range in a single-junction cell has the benefit that the cell remains close to optimal efficiency in the varying spectral conditions of a typical terrestrial concentrator. Though monolithic multi-junction cells have significantly higher efficiency, the series-current constraint means that some of this advantage is lost as the illuminating spectra and the cell temperature change from the values at which the tandem was optimised. The good material quality which can be achieved with these structures makes the cell dark current at the typical operating conditions expected under moderate sunlight concentration (∼200×), increasingly dominated by radiative processes the deeper the quantum wells. We will report on high concentration measurements of strain-balanced quantum well solar cells with and without Bragg-stack reflectors and discuss the “additivity” between the short-circuit current and the dark-current. We discuss a 50 shallow well cell with measured AM1.5d efficiency of (26 ± 1)% at around 200× concentration. This is approximately 2% higher than a comparable p–n cell with comparable material quality. The good material quality is also responsible for another effect previously observed in single quantum wells becoming measurable in structures with 5 and 10 wells, that is the suppression of carrier recombination in quantum wells with respect to expectations assuming that the quasi-Fermi level separation in the depletion region is equal to the cell output voltage throughout the active region. The latest results are presented together with possible explanations for this effect both in the dark and under illumination. Finally a brief discussion about the potential applications of quantum well solar cells completes the paper.

[⇓][1] SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” Edited by V. Brusasco, R. Crapo and G. Viegi Number 4 in this Series [1]: #F4

Strain-balanced quantum well solar cells (SB-QWSC) extend the photon absorption edge beyond that of bulk GaAs by incorporation of quantum wells in the i-region of a p–i–n device. The addition of a distributed Bragg reflector (DBR) can substantially increase the photocurrent with little or no detriment to the dark-current. Experimental results are presented that show improvements of DBR cell efficiencies over SB-QWSC's without DBR's. In addition, at high dark-current levels appropriate to high concentration, we observe that the dark-currents of the SB-QWSC's exhibit ideal diode behaviour. We present evidence that the ideality n = 1 dark-current is reduced in the DBR cells and discuss the possible efficiency improvements if the dark-current is radiatively dominant.

The inclusion of quantum wells in p-i-n solar cells leads to both an increase in photocurrent and a reduction in open circuit voltage. It has been shown that up to 50 shallow strain-balanced GaAsP/InGaAs quantum wells can be inserted into a GaAs cell resulting in an increase in photocurrent that is greater than the reduction in Voc, leading to higher cell efficiency [1]. We present an investigation into the effects of a further increase in well number. The spectral response and IV characteristics of a 65 well quantum well solar cell and an otherwise identical 50 well cell are presented and compared. In addition, the ideality n = 1 dark currents obtained from these samples at concentrator current levels are studied. The predicted and measured light current densities under forward bias are compared at one sun illumination and demonstrate additivity to a good approximation. The results obtained suggest that cell efficiency decreases as well number increases from 50 to 65. Additionally, a 65 well cell of reduced exciton wavelength is also considered and found to demonstrate additivity at AM1.5 g short-circuit current levels and projected efficiency equal to that of the 50 well cell.

Background: Aqueous contrast swallow study is recommended as a screening procedure for the evaluation of esophageal anastomotic integrity following esophagectomy. The aim of this study was to assess the accuracy of water-soluble contrast swallow screening as a predictor of clinically significant anastomotic leak in patients with esophagectomy. Patients and Methods: The records of 505 consecutive patients undergoing esophagectomy in Mayo Clinic from January 1991 through December 1995 were retrospectively reviewed. 464 (92%) pa tients had water-soluble contrast swallows performed in the early postoperative period (median postoperative day 7, range 4–11 days). Results: A total of 39 radiological leaks were obtained but only 17 of these had clinical signs of anastomotic leakage. Furthermore, 25 patients who had normal swallow study developed a clinical anastomotic leak. There were therefore 22 (4.7%) false positive and 25 (5.4%) false negative results giving values for the specificity, sensitivity and false negative error rate of the radiological examination of 94.7, 40.4, and 59.5% respectively. Aspiration of the contrast agent was noted on fluoroscopy in 30 (6.5%) patients. Only 2 (0.4%) patients developed aqueous contrast agent-caused aspiration pneumonia. There was no procedure-related mortality. Conclusion: While radiological assessment of esophageal anastomoses in the early postoperative period using aqueous contrast agents appears to be a relatively safe procedure, the poor sensitivity and high false negative error rate of this technique, when performed on postoperative day 7 and in a series with clinical anastomotic leak rate of 9%, is insufficient for it to be worthwhile as a screening procedure.

On exposure to carbon dioxide (CO2) at a pressure of 3 bars, compacts formed from pressed ground slag, and 12.5 weight percent water, were found to react with approximately 18% of their own weight of CO2. The reaction product formed was calcium carbonate causing the slag to self-cement. Unconfined compressive strengths of 9MPa were recorded in carbonated compacts whereas strengths of1 MPa were recorded in non-carbonated slag compacts. As molten stainless steel slag containing dicalcium silicate (C2S) cools it can undergo several phase transitions. The final transformation from the beta-polymorph to gamma-C2S is accompanied by a volume change that causes the slag to self-pulverise or 'dust'. As a consequence of this the fine grained portion of the slag contains more of this phase whilst the coarser particles of the slag contain more of the calcium magnesium silicates that contribute the bulk of the waste. The fine fraction (125 microm) of the slag when ground is found to react to the same extent as the ground bulk slag and produces compacts with equivalent strength. A coarser fraction (4-8 mm) when ground to a similar grading does not react as extensively and produces a weaker product. Additions of ordinary Portland cement (OPC) at 5 and 10 percent by weight did not alter the degree of reaction during carbonation of the bulk slag or ground fine fraction, however the strength of the 4-8 mm fraction was increased by this change.

The acid neutralisation capacity test is widely used to assess the long‐term performance of waste materials prior to disposal. Samples of fixed mass are exposed to increasing additions of nitric acid in sealed containers and the resultant pH is plotted as a titration curve. In this work, the acid neutralisation capacity test was used in the assessment of an accelerated carbonated stainless steel slag. Difficulties arose in applying the test procedure to this material. This was largely because of the raised pressure from significant volumes of released carbon dioxide trapped in the sealed sample containers, causing an alteration to leachate pH values. Consequently, the acid neutralisation capacity test was modified to enable testing of samples in equilibrium with the atmosphere. No adverse effects on the results from testing of a carbonate free material were recorded

Chemically andthermally stable high surface area catalyst supports are neededto facilitate a vast array of chemical reactions. One approach is to augment an otherwise vulnerable high surface area material such as activatedcarbon with a robust surface coating. Here a high-temperature #uidized bed reactor-based method for the production of silicon-carbide-(SiC) coated activated carbon is described. At 13503C, gaseous silicon monoxide reacts at the carbon surface to form -SiC andcarbon monoxid e. The resulting carbide coating confers improved resistance to thermal and chemical degradation while maintaining signi"cantly high surface areas. The resulting composite materials are characterizedby scanning electron microscopy, X-ray di !raction, X-ray #uorescence, electron microprobe, BET surface area, andthermogravimetric analysis. 2001 Elsevier Science Ltd. All rights reserved.

The volume dependence of single breath carbon monoxide diffusing capacity (DLCO) and carbon monoxide transfer coefficient (K CO) was determined in 24 healthy subjects. The change in DLCO [fraction of DLCO measured at total lung capacity (TLC)] to change in alveolar volume [fraction of alveolar volume (VA) at TLC] closely fitted a simple linear regression and matched a theoretical model. As VAdecreased, DLCO fell linearly and K CO increased as expected from the relation of DLCO to VA. The equations for adjustment of predicted DLCO and K CO for alveolar volume are:DLCO/DLCOtlc=0·58+0·42 VA/VAtlcKCO/KCOtlc=0·42+0·58/(VA/VAtlc)DLCO and K CO were evaluated in 2313 patients. Subgroups of patients with asthma, emphysema, extrapulmonary lung disease, interstitial lung disease and lung resection were identified. Unadjusted DLCO and K CO percent predicted values showed large differences and much variability, so can be misleading. As expected, K CO and DLCO percent predicted values adjusted for alveolar volume were nearly identical. Subgroups have characteristic patterns of V A and unadjusted and adjusted DLCO and K CO. Changes in DLCO and K CO with alveolar volume are relevant for accurate interpretation of diffusion in patients with low lung volumes. Adjusting predictedDL CO and K CO for alveolar volume provides a better assessment of lung function.

Pretreatment for 5 h with 10 μg phorbol-12-myristate-13-acetate (PMA), a well established activator of protein kinase C (PKC) in many kinds of cells including macrophages, was found to either (a) delay, or (b) potentiate, lethal endotoxin shock in mice, depending upon the dose of LPS. The latter occurred despite a marked attenuation (>90%) of the TNFα response to LPS. In mice sensitized with D-galactosamine the same PMA pretreatment offered protection against challenge from either LPS or TNFα. This protection, coupled with the ability of PMA to reduce serum TNFα while increasing serum corticosterone in response to LPS, adds in vivo support for a possible role for PKC activation in early endotoxin tolerance. A phorbol ester (4α-phorbol) that is not a PKC activator was found ineffective. PMA produced a prompt and profound decrease in body temperature which reached a nadir at 3 h. However, the protective effect produced by PMA was not dependent upon a decrease in body temperature per se, but was dependent upon administration of PMA at the same time or prior to LPS.

This paper presents key magnetic design considerations and analyses performed on the Superconducting Super Collider (SSC) High Energy Booster dipole magnets (HDM). The design considerations include: optimization of the cell cross section to establish low magnetic field harmonic content and specified field strength throughout a wide range of cable azimuthal sizes; effects of wedge geometry and cable stacking procedures on the field harmonics; and effects of yoke geometry and material variations on the central field strength and harmonics of the magnet. >

Several studies have provided evidence that epidermal growth factor (EGF) or transforming growth factor alpha (TGF alpha) mediate some of the physiological effects of estrogen. The object of the present study was to determine whether exogenous EGF could initiate embryo implantation in the rat, a response known to depend upon the action of estrogen in a progesterone-primed uterus. Immunocytochemical examination showed the presence of immunoreactive EGF, TGF alpha and the EGF receptor in luminal glandular epithelium of uteri on days 4,5 and 6 of pregnancy. EGF receptor was also present in the implanting embryo and in decidual cells of the uterine stroma. Attempts to initiate implantation by intravenous injection of murine EGF into ovariectomized or hypophysectomized delayed-implanting rats maintained with progesterone were unsuccessful. Implantation sites were found, however, in 24 of 33 (73 per cent) hypophysectomized progesterone-primed rats given 100 micrograms EGF immediately after intrauterine transfer of blastocysts from hypophysectomized delayed implanting animals. Although EGF is capable of initiating implantation in the delayed implanting rat model it remains to be determined whether this growth factor is responsible for the implantation inducing action of estrogen in vivo.

A method for the automated and accurate calculation of the winding eddy losses, as well as the stray losses in the tank walls, core support frame, lockplates, and the core laminations in core-form power transformers is described. Comparisons between this method, test values, and other analytical results are presented for a number of commercial transformers. These comparisons prove the validity of the method and the superior accuracy it provides. The calculations provide an accurate estimate of the relative contribution of the various loss components to the total load losses of the transformer. Hence, it can be used to evaluate methods of reducing these losses. This capability is demonstrated. >

Presentation of Case A 77-year-old man was admitted to the hospital because of progressive exertional dyspnea and worsening cough. There was a history of 35 years of smoking two to three packs of cigarettes daily, a habit that he discontinued 20 years before admission. Thirteen months before entry an x-ray film of the chest (Fig. 1) showed small lung volumes and diffuse linear opacities throughout both lungs that were more prominent at the bases; the heart and mediastinum appeared normal. A CT scan of the thorax (Fig. 2), obtained 10 months before entry during an episode of pneumococcal pneumonia, revealed . . .

To meet electrical performance requirements, the industry is implementing ultra-low dielectric constant (ULK) materials in the back end of line interconnect structure. ULK dielectrics are inherently weak compared to traditional dielectrics and pose significant challenges to electronic packaging processes and reliability. Accurate mechanical properties are a prerequisite for upfront risk assessments associated with low-k integration using numerical simulations. In this paper, techniques used to characterize ULK dielectric elastic modulus and in-plane/out-of-plane coefficient of thermal expansion will be presented and the data for a candidate ULK dielectric will be summarized. Nanoindentation of ULK films on substrate was used to determine the plane strain modulus. In the direction normal to the film, the temperature gradient of the thermal expansion strain along the film thickness was measured by X-ray reflectivity. In the plane of the film, the temperature gradient of the biaxial thermal stress was obtained by the substrate curvature measurements. A method to deduce Poisson's ratio of the thin ULK film is proposed using the data from the afore-mentioned characterization techniques.

To the Editors: In 1986, the American Thoracic Society (ATS) first suggested a fixed ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC)

The incorporation of strain-balanced quantum wells into a GaAs solar cell extends the spectral response resulting in a photocurrent increase that can exceed the reduction in voltage performance, leading to higher overall efficiencies [1]. At concentrator current levels the main carrier loss mechanism is radiative recombination from the quantum wells. We have recently reported on evidence of hot carrier effects in the quantum well regions of GaAs based strain-balanced cells incorporating InGaAs quantum wells and GaAsP barriers [2]. This paper extends this work to a greater range of samples, and reports on a bias-dependent broadening in exciton luminescence observed in all samples at high biases. We present two possible interpretations of the data using different parts of the generalised Planck equation.

Udgivelsesdato: 2007-Mar

The strain balanced quantum well solar cell (SB-QWSC) provides a novel method of engineering the bandgap of a p-i-n junction to better match the terrestrial solar spectrum. The ability to accurately model the spectral response of a SB-QWSC is vital in optimising cell design. We present a study into two major components of such a model. Firstly, we provide an overview of the model for the confined energy levels within SB-QWSCs and outline the method used to determine a vital parameter for such calculations; the conduction band offset. Secondly, a critical evaluation of the hole in-plane effective masses (required to model the device absorption) is given. A multi-band k.p model is used to calculate the in-plane valence band dispersion and values for the effective masses are extracted from fits to the resulting E-k curves. The results of these investigations are then used to model the spectral response of a typical SB-QWSC. Good agreement is observed between absolute prediction and measured quantum efficiencies.

GaAs based Strain-Balanced Quantum Well Solar Cells (SB-QWSCs) have been shown to enhance efficiency compared to a bulk control cell, if the overall photocurrent increase is not offset by the reduction in open-circuit voltage [1]. Here we demonstrate the performance of QWSC in light fluxes of up to 400 suns equivalent. The QWSC maintains additivity (the total current is the sum of dark current and the photocurrent) at these concentration levels and we demonstrate an efficiency of 27.0% at 328 suns for a SB-QWSC under the low aerosol optical density spectrum (AOD). The SB-QWSC is a p-i-n structure with 50 In0.1Ga0.9As wells in the i-region and a 20 period stair-case distributed Bragg reflector (DBR) optimized to reflect light in the stop-band range of (880-930)nm. The entire device is grown monolithically in a robot-loading 7×2 Thomas Swan Shower-Head Reactor recently commissioned at the University of Sheffield.

Photon self-absorption or photon recycling (PR) can be used in strain balanced quantum well solar cells (SB-QWSC) to achieve higher device efficiencies. By growing SB-QWSCs on distributed Bragg reflectors (DBR) suppression of the device dark-current and changes in electro-luminescence (EL) spectra have been observed when compared to devices grown on GaAs substrates. The dark-current is suppressed in the region with ideality factor n = 1, which corresponds to ideal Shockley and radiative recombination, while there is no difference in dark-currents in the region where the ideality factor n is ~2 and non-radiative Shockley-Read-Hall recombination is dominant. DBR SB-QWSCs in which the dark-current is dominated by radiative recombination benefit not only from enhancement of short-circuit current (JSC) due to increased absorption of normal incident photons but also from enhancement of open-circuit voltage (VOC) from PR. Experimental and modeling results of SB-QWSC devices will be presented in the paper. These results show that with optimal device design both the Jsc and VOC can be increased significantly at the same time. Most importantly, to date PR has only been observed in dark-current measurements on fully metalised photodiode structures; but we will show current-voltage characteristics in devices under high concentration which reveal a suppression of the radiative dark-current in DBR devices compared to those without DBRs. The results presented here convincingly demonstrate, for the first time, the PR effect in SB-QWSCs under high concentration.

Publisher Summary This chapter focusses on quantum well solar cells and quantum dot concentrators. This chapter reviews the development over the past half a decade of the quantum well solar cell (QWSC) and the quantum dot concentrator (QDC). The study of nanostructures such as quantum wells (QWs) and quantum dots (QDs) has dominated opto-electronic research and development for the past two decades. The chapter also reviews recent advances since then, concentrating in particular on studies of the strain-balanced quantum well solar cell (SB-QWSC) as a concentrator cell and the thermodynamic modelling of the QDC. The SB-QWSC offers a way to extend the spectral range of the highest efficiency single-junction cell, the GaAs cell. It discusses the way this can in principle lead to higher efficiency in both single-junction and multi-junction cells and offers particular advantages in high-concentration systems. The high efficiency, wide spectral range, and small cell size make these systems particularly attractive for high concentration, building-integrated applications using direct sunlight. The chapter also demonstrates a 3D thermodynamic model capable of describing the performance of dye-doped and QD-doped slabs of luminescent concentrators. The model is a powerful tool for analyzing the performance of the luminescent concentrators. The fits show that concentrator performance is currently limited by the quantum efficiency (QE) of the QDs dispersed in the plastics.

The effects of 60 Hz 30 and 100 pT magnetic fields on the sleep cycle of Sprague-Dawley rats are investigated. The irradiated rats slept for short (2 hour) periods at random intervals as compared to control rats, who slept for a single 8 hour period. The results suggest that the magnetic field affected the functioning of the pineal gland, and therefore the rat's nocturnal sleeping cycle.

In this paper , the characteristics of manual dexterity are defined and analyzed. A method of measurement is developed to support a numerical rating system. The purpose of this system is to quantify the physical aspects of manual dexterity independent of higher neural ability. The fourteen knuckled joints (three per finger, two per thumb) of the hand are analyzed separately. The numerical ratings of these physical characteristics can be used to objectively assess the functional state of the hand replacing dependence on subjective observation.

The radiative behavior of GaAsP/GaAs/InGaAs strain-balanced quantum well solar cells (SB-QWSC) with 1, 5 and 10 wells was studied. Quantum efficiencies were measured and fitted by the model SOL. Electroluminescence (EL) spectra were predicted according to a generalized detailed balance treatment assuming a quasi-Fermi level separation (QFLS) equal to the applied bias. By comparison to experimental EL spectra, a reduced QFLS was found in all three samples confirming results obtained in strained single and double quantum wells. Photoluminescence (PL) measurements conducted on the single well SB-QWSC showed that the QFLS reduction also occurred in the light as for the strained single well sample.

SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” Edited by V. Brusasco, R. Crapo and G. Viegi Number 5 in this Series This section is written to provide guidance in interpreting pulmonary function tests (PFTs) to medical directors of hospital-based laboratories that perform PFTs, and physicians who are responsible for interpreting the results of PFTs most commonly ordered for clinical purposes. Specifically, this section addresses the interpretation of spirometry, bronchodilator response, carbon monoxide diffusing capacity ( D L,CO) and lung volumes. The sources of variation in lung function testing and technical aspects of spirometry, lung volume measurements and D L,CO measurement have been considered in other documents published in this series of Task Force reports 1–4 and in the American Thoracic Society (ATS) interpretative strategies document 5. An interpretation begins with a review and comment on test quality. Tests that are less than optimal may still contain useful information, but interpreters should identify the problems and the direction and magnitude of the potential errors. Omitting the quality review and relying only on numerical results for clinical decision making is a common mistake, which is more easily made by those who are dependent upon computer interpretations. Once quality has been assured, the next steps involve a series of comparisons 6 that include comparisons of test results with reference values based on healthy subjects 5, comparisons with known disease or abnormal physiological patterns ( i.e. obstruction and restriction), and comparisons with self, a rather formal term for evaluating change in an individual patient. A final step in the lung function report is to answer the clinical question that prompted the test. Poor choices made during these preparatory steps increase the risk of misclassification, i.e. a falsely negative or falsely positive interpretation for a lung function abnormality or a change …

Publisher Summary This chapter illustrates how the different sample handling regimes influence the morphology of the surface of the sample as viewed in a scanning electron microscope. By handling samples in different ways it is possible to examine the carbonate formed at different point and therefore examine the morphology of the products formed under peak conditions and as a consequence of subsequent pore-water degassing. Under relatively low magnification the differently handled samples appear to be nearly identical. An uneven poorly crystalline reaction product is observed to form first coating grains of ordinary Portland cement exposed to supercritical CO2 at 105°C and 80bar for 24hours. The apparent abundance of crystalline reaction product on the surface of the sample is not necessarily indicative of a high degree of reaction as the bulk of the carbonate is contained in the more amorphous layer that coats the original sample grains.

[⇓][1] SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” Edited by V. Brusasco, R. Crapo and G. Viegi Number 3 in this Series [1]: #F7

Publisher Summary As a preliminary stage of an investigation into the reaction of a range of materials with carbon dioxide under supercritical conditions the effects of altering different portions of the experimental protocol were assessed using ordinary Portland cement (OPC) as the initial mineral assemblage. Ordinary Portland cement is a mixture of calcium and calcium aluminum silicates formed at high temperature and are therefore highly reactive with respect to moist carbon dioxide. The ease, with which OPC reacts, means that short duration experiments can be performed with sufficient yield to enable differentiation between the amount and nature of the product formed. In order to investigate the strength of effect and the degree to which it can affect the measured yield of any carbonation experiment a series of samples are reacted and then handled in different ways in order stop the reaction at different points. The chapter presents the experimental results. The variation in results depending upon the pressure temperature time path of the reaction shows that the full history of a sample is required if the results of subsequent analysis are to be usefully interpreted.

The optical configuration of the presented sensor consists of three imaging lenses mounted on a pair of eyeglass frames around the field of vision. This allows normal eye movement and unobstructed vision without distracting the subject. The optical sensors gather light reflected from the area of the sclera to the immediate left and right of the iris and transmit this light through optical fibers to remote detectors. The device determines horizontal position by utilizing the difference in reflectivity between the iris and sclera. Vertical position of the eye is determined similarly by monitoring either the upper or lower eyelid. Point-of-gaze and short period tracking measurements have been made in two dimensions with an accuracy of better than half a degree in the horizontal direction and three degrees in the vertical direction. >

The physiological fitness of the fourteen knuckled joints is analyzed to provide the basis for a numerical rating of physical manual dexterity. A method has been developed to test and analyze defined characteristics. A test algorithm is actuated by a computer which queues subject action, records subject response in EMG signals and joint angle amplitudes, and analyzes response patterns. Average physical performance patterns are examined and integrated into a quantitatively based numerical measurement system standardized by observational and experimental means. This system objectively assesses the functional ability or state of the fingers and hand, replacing the dependence on subjective observation. This provides examiners with a robust standard for monitoring and cross referencing digital fitness with a common and easily understood reference point. >

The characteristics of physical manual dexterity are defined and analyzed to provide the basis for a numerical rating system. Physical manual dexterity is based on the actual functionality and fitness of the hand and is assessed independently of higher neural ability. A method has been developed to test and analyze define characteristics. This method is expanded and integrated into a quantitative measurement system standardized by observational and experimental means. This will support a numerical rating of physical manual dexterity and can be used to objectively assess the functional ability or state of the fingers and hand, replacing dependence on subjective observation. This provides examiners with a robust standard for monitoring and cross referencing digital functionality with a common and easily understood reference point. >

An electrical stress model for a specific geometry of a stator coil cross-section has been developed and used to analyze various conditions that can exist in actual stator coils. A finite element program forms the basis for the model used in the analysis. The developed model is used to determine voltage distribution and electrical stresses in the coil cross-section. Results are obtained in the form of parametric curves which show how the electrical stresses vary as a function of Roebel filler permittivity, Roebel filler thickness and axial position. Plots of internal coil voltage distribution are shown. Analysis of groundwall electrical stress as a function of the curvature of the ground electrode is presented. In addition, voltage distribution is given for internal shielding, gap separations and as a function of filler dielectric constant. An automated model has been developed to perform analyses on coil designs of a wide range of configurations.

An exoskeleton system is being developed to aid in the mobilization of walking-impaired patients. New approaches to personal robotic assists have solved many classic problems with weight, power, endurance, and cost. A versatile platform of development allows for many variations and applications including mobility assist for the paralyzed, amputee, and spastic patient (MAPAS). A variety of strap on supports and braces are used, depending on the magnitude of the forces required. The MAPAS system utilizes compressed gas to power the main force producing elements, or muscles. Pneumatic muscles are used to provide controllable joint torque with moderate levels of pressure. These muscles are mounted to the brace, providing pull-only torque to joints. The MAPAS control system features interpreted joint mapping. The function of each leg joint is primarily directed through the output of a finger joint sensor. A six to eight sensor hand goniometer provides the system with user input. Higher control features actuated by on-board intelligent devices enable finger joint inputs to be enhanced providing balance, gait anticipation, fault-recovery, and spasm signature compensation. Ambient pressure levels of on-board reservoirs can be changed to suit changing environments ranging from heavily loaded amputee walking up stairs to the slight correction of a mild spasm. The entire system is portable with on-board batteries, compressed air reservoirs, intelligent algorithms, and goniometric sensors.

A modified transcutaneous electric nerve stimulator (TENS) stimulation waveform was implemented in an experimental prototype unit. The new stimulation waveform was developed to increase electrical power transfer to human tissue. This waveform differs from those generated in traditional TENS in both shape and spectral content. A pilot study of skin impedance using TENS electrodes was performed. The gain and phase of skin impedance were measured, and the results were consistent with a first order system across the entire subject population. Individual skin impedance profiles did not vary significantly with respect to skin preparation, texture, or moisture. Bode plots were made of data from inter-electrode measurements on subjects with both prepared and unprepared skin. Results revealed that electrode-to-electrode surface resistance can be modeled as a first order low pass filter. The new stimulation waveform was developed to provide more energy within the resistive portion of the skin impedance profile. This spectral shaping increases real power transfer to the skin by spectrally matching the waveform to the resistive frequency range of the skin. The distributed spectral energies for the new prototype waveform and a traditional TENS device stimulation waveform were multiplied by the skin impedance to provide a theoretical measurement of effective power transfer. This effective power transfer ratio was calculated for the two waveforms. The prototype waveform showed a 80% theoretical effective power transfer increase over the traditional waveform. An assessment of TENS function was done in a pilot test with chronic TENS users. The results showed that a spectrally matched waveform is more electrically efficient, allows more stimulation amplitude without causing irritation, is more comfortable in the long term, causes minimal nerve stimulation, and does not induce erratic skeletal muscle quiver.

Summary form only given. Intense pulsed ion beams have been be used to achieve a rapid melt and resolidification (RMR) of the surface layer of metals, ceramics, and silicon. This leads to enhancements in wear durability and corrosion resistance. RMR treatment has been applied both to simple alloys and alloys onto which a thin-film coating has been applied. The beam then mixes this coating into the substrate. The nature of beam-induced effects depends upon the treatment ion(s). In particular, heavier beam ions (e.g. N, Kr, Xe) produce a smoother surface topography compared to proton treatment. We report on experiments aimed at optimizing beam parameters from these heavier ions. Alloys and bi-metal combinations were treated on the RHEPP-I facility at Sandia National Laboratories (0.5 MV, up to 0.5 us at sample location