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Oxidation and hot corrosion behaviors at 900 °C of Nb−Si based ultrahigh temperature alloys were investigated. Both oxidation and hot corrosion kinetics curves of the alloy involve an initial parabolic stage and a later rapid linear stage. In the initial oxidation stage (1−50 h), a thin and continuous scale is formed on the alloy surface, while severe pest degradation phenomenon is observed in the linear oxidation stage. Compared with oxidation of the alloy in static air, a linear hot corrosion stage happens earlier and catastrophic scale disintegration occurs after hot corrosion for 20−100 h, demonstrating that molten salts (Na2SO4 and NaCl) could significantly accelerate the oxidation process of the alloy. STEM results indicate that the corroded scale consists mainly of TiO2, Nb2O5, TiNb2O7, amorphous silicate and NaNbO3.

This review intended to comparatively explain and present the most important medical use and biological impact of poly-lactides and lactide-based composites. The utilization and degradation of compounds based on lactic acid and polylactides is described in detail. Understanding the metabolism and degradation phenomenon and the factors that potentially influence it is key to modulating their properties as well as their characteristics driven from the fabrication procedures and the fields of use. All these are commented according to the clinician's criteria. The current debate on the advantages and shortcomings of various resorbable polymeric materials categories is also analyzed, from the perspective of the users of resorbable polylactide-based biomaterials. The scientific literature comprises either distinct chemical and physical or specific animal or medical description of resorbable materials; so that in compensation, the present review covers all topics for the most appropriate comprehensive update of the reader.

Two Burmese oil paintings on zinc supports depicting portraits of royal families, dated to the early 20th century by Saya Aye and Saya Mya, showed interesting corrosion, efflorescence and soapy globules for analytical investigation prior to conservation for exhibition. The features and colours on the two paintings, one of which was in worse condition than the other, were obscured by a whitish haze. Paint rupture and losses due to corrosion of the zinc support were apparent. Using a combination of 3D digital microscopy, FTIR microscopy and SEM–EDS, the degradation, as well as the paint materials and artists’ techniques were analysed and discussed. Zinc soaps, oxalates, silicates, hydroxychlorides, carbonates, wax and mould characterized the haze. Interestingly, brown outlines in Aye’s painting appeared unusually dark. Upon analysis, this degradation phenomenon was attributed to micro-sized greenish soap globules that have developed around copper/zinc (brass) particles, causing the brown outlines to lose their intended luminosity. The other painting by Mya, in which the same brown outline was applied, did not show such formation of globules. Detection of oxalates in the corrosion of zinc support and brown outlines are discussed. This study shows the importance in understanding the artists’ materials and techniques, which have consequential effects to the degradation observed.

Polymer drag reduction agents are easy to degrade during application. The drag reduction and mechanical degradation characteristics of polyethylene oxide were investigated in this research. A rotat...

Carbon deposition is one of the major degradation sources, which reduces the activity of solid oxide fuel cells (SOFC) and it can even cause irreversible cell degradation. In order to counteract this phenomenon and thus to extend the SOFC lifetime, development of effective cell-protecting strategies for carbon re-gasification and restoring of the cell performance is of crucial importance, since other methods considering prevention of this degradation phenomenon can mean an increased system complexity or reduced system performance. In the literature there is very limited data relating to the performance of SOFCs after the carbon removal process has been executed. This study aims to analyze carbon removal techniques and moreover their effect on the SOFC performance as well as possibilities for industrial application. Various innovative approaches for carbon re-gasification are scrutinized and detailed explained within this study on 20 samples, which further help to provide potential carbon removal procedures relevant for industrial SOFC systems.

This paper proposes a novel error monitoring scheme for memristor-based Material Implication (IMP) logic. The novel monitoring method utilizes differences in the voltage of sourceline (VSL) under different input cases after IMP operation, to detect two major types operation failures caused by gradual degradation phenomenon of memristor’s positive threshold voltage $(V_{close})$. Simulation results under PVT variation show that the proposed error monitoring circuit in 0.18 $\mu$m technology can perform successful failure detection within two operation cycles, which can be used for periodic memristors failure detection and adaptively adjusting operation voltages during memristive IMP operation.

This study evaluated the solid particle erosion characteristics of 2.25Cr–1Mo steel with aging time. Aging was performed at 750 °C until 100 h. Specimens aged at each time were characterized by microstructure analysis and Micro-Vickers hardness. An erosion experiment was conducted using 100~200 μm of stainless steel shot at a flow velocity of 20 m/s for 4 h. A consequently, a microstructure degradation phenomenon in which Cr-rich carbide was coarsened occurred, and the surface hardness decreased by 45%. With a decrease in the hardness, the solid particle erosion damage increased and the erosion damage type changed.

A light-induced degradation phenomenon of unknown origin in p-type Cz-Si passivated emitter and rear cell (PERC)-type solar cells is thoroughly investigated by collating results from different measurement techniques and predictions from various simulations. The observed degradation manifests in slight losses in j sc , strong losses in V oc, and devastating losses in FF, and thus massively impacts efficiency. It is found that the series resistance degrades significantly due to a degradation of front contact resistance. This, however, does not explain losses in V oc and j sc , which are attributed to the degradation of a different cell component. Neither a degradation by defect formation in the space charge region, nor the emitter, nor the bulk is found to consistently explain the observations. Only a rear surface-related degradation mechanism explains consistently all experimental findings.

Nanoparticles (NPs) are unique may be organic or inorganic, play a vital role in the development of drug delivery targeting the central nervous system (CNS). Intranasal drug delivery has shown to be an efficient strategy with attractive application for drug delivery to the CNS related diseases, such as Parkinson's disease, Alzheimer 's disease and brain solid tumors. Blood brain barrier (BBB) and blood-cerebrospinal fluid barriers are natural protective hindrances for entry of drug molecules into the CNS. Nanoparticles exhibit excellent intruding capacity for therapeutic agents and overcome protective barriers. By using nanotechnology based NPs targeted, drug delivery can be improved across BBB with discharge drugs in a controlled manner. NPs confer safe from degradation phenomenon. Several kinds of NPs are used for nose to the brain (N2B) enroute, such as lipidemic nanoparticles, polymeric nanoparticles, inorganic NPs, solid lipid NPs, dendrimers. Among them, popular lipidemic and polymeric NPs are discussed, and their participation in anti-cancer activity has also been highlighted in this review.

Bipolar degradation phenomenon, in which the on-state forward voltage increases with the expansion of stacking faults, is a significant issue for practical applications of 4H-SiC bipolar devices such as PiN diodes and IGBTs. This paper addresses methods realizing suppression of the degradation phenomenon by adopting carrier lifetime control techniques.

Full-ceramic dental restorations made from ZrO 2 have become increasingly popular due to their aesthetics and mechanical strength, and are gradually replacing prostheses made of porcelain fused to metal. Nevertheless, due to the variability in the physicochemical properties in a wet environment at elevated temperature, zirconia is quite a controversial material, the use of which in the environment of the mouth is questionable and raises many concerns. The reason for the variability in the physicochemical changes is the martensitic transformation in which metastable phases (β, γ) change into the stable phase (α). For biomedical applications, the most desired is the β-phase. A very unfavourable phenomenon accompanying the martensitic transformation in a wet environment is low temperature degradation, which is an autocatalytic process accelerating negative changes in ZrO 2 . The aim of this review is a comprehensive study of the degradation phenomenon problems according to prosthetic treatment with a fixed prosthesis and ways to reduce it.

A gamma process model is widely used to estimate reliability of general systems using non-destructive degradation data. However, the daunting challenge is the application of the model to one-shot systems given that recursive measurements are unavailable and degradation trends over time are nonlinear. This study shows a storage reliability estimation method of one-shot systems using accelerated destructive degradation data when information of either chemical reaction or degradation trend is unknown. An n-th kinetic model, which is a Physics-based model, was used to evaluate the degradation phenomenon of one-shot systems using destructive degradation data. The accelerated degradation model was constructed to estimate storage reliability for normal storage temperature. The proposed method was applied to estimate storage reliability of IR flare using the stabilizer contents that were destructively measured over time at three temperature levels. The real application results show applicability of the proposed method.

Bonding wedges are one of the most important tools in wire bonding process. The performance of bonding wedge determines the flexibility, reliability, cost of bonding process. The degradation of bonding wedges occurs frequently during bonding process which results in bonding failure and reliability problems. In this paper, common bonding tools were introduced. The degradation phenomenon of bonding wedges were studied using repeated experiments. The resultant on wedge tip induced degradation was analyzed. A cleaning tool tray and an ultrasonic cleaning method using sodium hydroxide were proposed to remove the resultant. The results showed that the degradation without obvious wear on wedge tip was caused by the resultant containing additional silicon which came from gold wire. By using cleaning process when degradation occurred due to resultant, the wedge could work properly until wear by nature.

The main purposes of this manuscript are to report a surprising and interesting degradation reaction of glucagon from a specific vendor in which glucagon underwent cleavage among several peptide bonds quickly under near neutral to basic conditions, and to propose the root cause of mechanism for the degradation reaction. The degradation reaction was monitored by HPLC and the fragment structures were confirmed by LC-MS. Possible impurities responsible for the degradation were either confirmed or excluded by a variety of techniques such as addition of chelator EDTA and transitional metal ions or separation by ultrafiltration. This type of degradation was rarely reported in literature, especially considering its extreme cleavage efficiency. Contamination by a thermostable high molecular impurity (such as a peptidase with molecular weight between 10 and 30 KDa) during the manufacturing process was the main reason for this interesting phenomenon. The degradation phenomenon described here could be used as an excellent example showing that products ordered from vendors meeting the rudimentary quality standards might contain impurities which could cause significant degradation. We suggest that a simple solution, i.e. additional tests of stability under real or accelerated conditions by manufacturers and inclusion of the “accelerated stability criteria” in the Certificate of Analysis (CoAs), especially for sensitive biological reagents prone to faster degradation, would be very helpful for avoiding losses for both vendors and users.

The real-time monitoring of railway vehicles is becoming a key factor for safety and the optimization of the maintenance costs. In this context, the secondary anti-yaw suspension system represents a key element, subjected to degradation phenomenon. This paper presents a model-based real time monitoring technique of the anti-yaw damping. The approach is based on a constrained nonlinear estimation procedure that employs a railway vehicle modelling characterized by the presence of a random walk model for the wheel-rail interaction. The technique allows to employ a model-based approach, with advantages in terms of robustness respect to the interaction parameters, a priori no knowledge of the track irregularities and constraints applied to the estimated states.

Atomic structure and lattice dynamics properties of the novel configurations of VN4 and VN4H defects in combination with the {001} platelet structure in diamond are investigated by first-principles density functional techniques. We find that incorporation of B centers (VN4) in the platelet structure substantially reduce the formation energy of B centers by ~0.45 eV for both structure models, suggesting that they may tend to develop preferentially together with platelets. Moreover, our results provide evidence that VN4 centers in the platelet might be effective sinks for atomic hydrogen in diamond. Vibrational properties of the defective structures are computed by using the linear response density functional perturbation theory (DFPT). N H stretching modes for VN4H centers appear around 3221 (model 1) and 3095 (model 2) cm−1, suggesting that the experimental vibrational modes of 3085.4, 3107 and 3237 cm−1 observed in natural IaA/B diamonds could be attributed to the VN4H defects. Moreover, we observed that incorporation of VN4H centers quenches the platelet IR absorption, which is unconventional but important in understanding the platelet degradation phenomenon. Our calculations shed light on possible novel configurations of VN4H centers and platelets, which can be extrapolated to VN4H2 centers as well as to a more hybrid platelet structure, and elucidate the role of nitrogen and hydrogen in the development of platelet defects in diamond.

On the example of the road pavement of a semi-rigid structure, this paper presents the concept of the parameters estimation of the experimental section tested after 30 years of use. In the context of the lack of technical history data of the analyzed road section, the resultant (conventional multilayer system, which is pavement and its subgrade) stiffness was analyzed in relation to the moment it was built. The analysis was performed using the concept of multilevel loadings, with the use of FWD-type equipment. The considerations are related to the slope coefficients of linear regression obtained on the basis of a research program in the range of the loads up to 90 kN. There were compared the differences between slope of the regression function for the force-deflection relation between the results of the deflection measurements of the test section after 30 years of use and the slope coefficients for the pavement structure parameters estimated on the basis of both expert judgments and computer simulations, as well as the back forecast. For the forecast, the properties of the stochastic process determined by the Poisson distribution were used.

Ageing of large transformer fleets is a challenge for utilities. To assess the condition of existing transformer fleets, transformer oil is commonly tested for multiple parameters and the data are recorded in large databases for subsequent interpretation. Through analysing multiple databases including oil test results and individual transformer details pertaining to UK in-service transformers operating at primary voltage levels of 33, 132, 275 and 400 kV, population analyses revealed a generic early degradation phenomenon as indicated by an early peak in acidity and 2-FAL trends with in-service age. By exploring the phenomenon from manufacturer, loading and oil chemistry change perspectives, results suggested that the early degradation was most likely due to an oil chemistry change resulting from hydrotreatment oil refining method introduced in the late 1980s. Judging from the faster degradation trend of the affected transformers, a separate asset management strategy may be needed.

This study presents a detailed analysis of the outdoor behaviour of organic photovoltaic (OPV) panels on a polytunnel type greenhouse roof in a Mediterranean climate, looking at the effects of environmental variables and panel orientations on the electrical behaviour and degradation of the panels, thus providing crucial outdoor testing results of greenhouse integrated OPVs in this climatic region. The OPV panel placed at the polytunnel ridge of the roof yielded highest outputs, efficiencies and fill factors during the measurement period. However, the use of panels on the East and West sides of the greenhouse roof, could reduce midday output peaks and therefore provide a more balanced power supply throughout the day. The diurnal variation in OPV behaviour was influenced by simultaneous effects of changing irradiance and temperature. It was found that although output was higher, the OPVs showed dips in fill factor and efficiency at times with high incident irradiance. This was assumed to be due to a reversible degradation phenomenon under high direct irradiance conditions, which led to higher performance during morning hours compared to the afternoon and was followed by a recovery overnight and to some extent in shaded conditions.

The present paper describes the synthesis of new palladium–oxazoline complexes in one step with good to high yields (68–95%). The oxazolines were prepared from enantiomerically pure α-aminoalcohols. The structures of the synthesized palladium complexes were confirmed by NMR, FTIR, TOFMS, UV–visible spectroscopic analysis and X–ray diffraction. The optical properties of the complexes were evaluated by the determination of the gap energy values (Eg) ranging between 2.34 and 3.21 eV. Their catalytic activities were tested for the degradation of Eriochrome Blue Black B (a model of azo dyes) in the presence of an ecological oxidant (H2O2). The efficiency of the decolorization has been confirmed via UV–visible spectroscopic analysis and the factors affecting the degradation phenomenon have been studied. The removal of the Eriochrome reached high yields. We have found that the complex9promoted 84% of color elimination within 5 min (C0= 30 mg/L,T= 22 °C, pH 7, H2O2= 0.5 mL) and the energetic parameters have been also determined.

This paper deals with the prediction of wafers quality, according to the health indicators of manufacturing equipments in the semiconductor industry. The proposed approach is based on the pattern recognition principle by using a historical data of health indicators, associated to the reconstructed data of quality measurements of wafers. The aim is to construct clusters that represent the normal and the known faulty operations. Then, the Remaining Useful Life in terms of number of Wafers (RUW) is estimated by monitoring the trajectory and velocity of the degradation phenomenon.

The same batch reactive powder concrete specimens were obtained with same raw materials and curing process, uniaxial compressive strength test had been done on the specimens after hot water curing placed in laboratory for seven days , three months and three years. The test results showed that seven-day strength and three-month strength of plain reactive powder concrete after hot water curing are almost equal. Strength of plain reactive powder concrete has not degradation within three months after hot water curing. While strength of plain reactive powder appears serious degradation phenomenon after placed in Laboratory for three years. Comparing uniaxial compressive strength test results of plain reactive powder concrete at three-month with three-year after hot water curing ,we find that strength of plain reactive concrete at three-year decrease about 27 percent than the strength of plain reactive powder concrete placed at laboratory for three months, and elasticity modulus increases about 71 percent, axial peak strain decrease about 62 percent respectively .With the passage of time, plain reactive powder concrete appears more Brittle Features and less toughness.

Noise removal from images is a part of image restoration in which we try to reconstruct or recover an image that has been degraded by using apriori knowledge of the degradation phenomenon. Noises present in images can be of various types with their characteristic Probability Distribution Functions (PDF). Noise removal techniques depend on the kind of noise present in the image rather than on the image itself. This paper explores the effects of applying noise reduction filters having similar properties on noisy images with emphasis on Signal-to-Noise-Ratio (SNR) value estimation for comparing the results., Comment: 4 pages,Published with International Journal of Computer Trends and Technology (IJCTT), volume 17 number 3, Nov 2014

Objectif: Contribuer a une meilleure connaissance de la flore de la foret classee de la Besso et de caracteriser les populations infiltrees et les cultures pratiquees dans cette foret classee. Methodologie et resultats: La foret classee de Besso (Cote d’Ivoire) couvre 23 100 ha sur est une foret dense semi-decidue a Celtis spp. et T riplochiton scleroxylon . La creation de clairieres culturales entre 1966 et 2012 malgre le classement de la foret est a l’origine d’une mosaique de vegetations secondaires incluses dans une matrice de foret « primaire » que nous avons plus particulierement etudie. Les releves de surfaces couples aux inventaires itinerants ont permis d’inventorier 474 especes, qui se repartissent en 330 genres et 91 familles. Les familles les plus abondantes sont Fabaceae, les Rubiaceae, les Euphorbiaceae, les Moraceae, les Malvaceae, les Meliaceae, les Moraceae, les Annonaceae, les Sapindaceae et les Poaceae. Parmi ces especes, 79 % sont des phanerophytes et 3 % des hemicryptophytes. Conclusion: Malheureusement, cette foret est en progressive degradation a cause des activites humaines qui menacent la biodiversite vegetale et animale de cette foret. Ainsi, pour reduire le phenomene de degradation des forets en generale, plusieurs actions de gestion durable pourraient etre entreprises par l’Etat, les ONG et la population. Notamment par la creation des zones de conservation de plantes par des mises en defens de jacheres. Mots cles: Biodiversite vegetale, Foret classee de la Besso, Cote d’Ivoire English Abstract English Title: Floristic diversity and human impact on Besso forest in Ivory Coast Objective: To contribute significantly to the knowledge of the flora of Besso forest and to evaluate the human impact. Methodology and results: The Besso forest in Ivory Coast) covers 23 100 ha and determines a potential vegetation corresponding to the Celtis spp.- Triplochiton scleroxylon semi-deciduous tropical forest. Shifting cultivation between 1966 and 2012 has led to a mosaic of secondary plant communities that are included in an old-growth forest matrix. For hundred seventy for (474) species were recorded in this forest during the field investigations, distributed among 330 genera and 91 families. The most common families were Fabaceae, Rubiaceae, Euphorbiaceae, Moraceae, Malvaceae, Meliaceae, Moraceae, Annonaceae, Sapindaceae and Poaceae. Among those species, 79 % and 3 % are phanerophytes and hemicryptophytes, respectively. Conclusion: Unfortunately, this forest is gradual degradation due to uncontrolled human’s activity. Thus, to reduce the degradation phenomenon of the forets in general, several actions of sustainable managements could be undertaken by the state, Non-Governmental Organisation (NGO) and the population. In particular by the creation of preservation zones of plants, the creation of collective gardens of plants. Keywords: Plant biodiversity, Besso forest, Ivory Coast

The potential benefits of lithium-ion batteries in the domestic sector are investigated. A particular household in UK with a PV panel of 4kW and a lithium-ion battery is selected. The benefits gained are estimated based on a CBA, taking into consideration the degradation phenomenon. In the suggested methodology, a simulation Matlab model is developed where a specific energy management strategy is applied. Different scenarios are considered and compared. The obtained results showed that a lithium-ion battery could be a cost effective solution for domestic users. A high dependence between the degradation effect, TOU tariffs, FITs, domestic energy consumption and the benefits gained was found.

Capacitance is a critical performance characteristic of high-voltage-pulse capacitor which is used to store and discharge electrical energy rapidly. The capacitors usually are stored for a long period of time before put into use. Experimental result and engineering experience indicate that the capacitance increases with storage time and will eventually exceed the failure threshold, which means that the capacitor may fail during storage. This is a typical mode of degradation failure for long storage products. Further, the capacitance degradation path can be extrapolated in several stages based on the shifting characteristics. That is, the capacitance increases slowly or fluctuates in the initial storage stage that lasts about three months. Then it increases sharply in the middle stage which lasts about four months. After the two stages, the capacitor enters into the third stage in which capacitance increases constantly. This degradation phenomenon motivates us to study the storage life prediction method ba...

Nowadays, the piezoelectric materials are widely used in many areas. The piezoelectric materials will undergo an electrical degradation process during working causes the piezoelectricity and resistance of the piezoelectric materials degrade. The existence of the electrical degradation phenomenon severely limits the applications of the piezoelectric products. During the electrical degradation process, electrical breakdown often occurs and this electrical breakdown has been proposed [1, 2] induces the resistance decrease and local phase changing. In this paper, the electrical breakdown induced current transients are detailed investigated. Three types of current transients are presented and the time durations of current transients are suggested not constant and corresponding to the time duration of the local burn-out process, which is caused by the heat released from the electrical breakdown process.

Bioengineered tissues created for transplant will be expected to survive and contribute to function over the lifetime of the individual. To evaluate potential intrinsic changes and degradation of the extracellular matrix of decellularized human tissue scaffolds, human decellularized tracheas were evaluated over a one year period in vitro . Human tracheas were decellularized and stored for one year in phosphate-buffered saline at 4 °C in the presence of antibiotics and anti-mycotics, and their structural, mechanical, and angiogenic properties compared to baseline values. Results showed that stored human decellularized tracheas were increasingly degraded resulting in a loss of extracellular matrix architecture – in particular of collagenous and elastic fiber structure –and decreased mechanical and angiogenic properties. The mechanical alterations of the extracellular matrix but not the deterioration and microstructure were not improved by using a natural cross-linking agent. These findings demonstrate that human decellularized tracheas, stored for one year in phosphate-buffered saline solution at 4 °C, would not meet the demands for a tissue engineering matrix and likely would not yield a suitable graft for lifelong implantation. The degradation phenomenon observed in vitro may be further enhanced in vivo , having clinical relevance for tissues that will be transplanted long-term and this should be carefully evaluated in pre-clinical settings.

Authors have studied the degradation phenomenon on contact resistance under the influences of an external micro-oscillation. They have developed a hammering oscillating mech-anism (HOM) or a micro-sliding mechanism 1 (MSM1) which provides micro-oscillations for electrical contacts. It is shown that each mechanism is able to simulate an actual degradation phenomenon on electrical contacts. And they have also developed the third mechanism, namely another micro-sliding mechanism 2 (MSM2) which provides micro-sliding driven by a piezo-electric actuator and elastic hinges, which has more precise sliding performance, less thermal drift on the sliding, and smaller sized system constituted of commercial parts.

Wall thinning due to flow-accelerated corrosion (FAC) is a pervasive form of degradation in feeder pipes of the primary heat transport system of CANDU reactors. Prediction of the end-of-life of a feeder from wall thickness measurement data is confounded by the sampling and temporal uncertainties associated with the FAC degradation phenomenon. This paper presents a probabilistic model of wall thinning due to FAC, and calibrates it with a set of feeder wall thickness measurements obtained from a CANDU plant. The proposed model derives the feeder lifetime distribution, which is useful in developing optimum strategies for life-cycle management of the feeder system.

Lead soap aggregateshave been-found in lead-containing oil paint layers in paintings from the thirteenth to the twentieth century. They severely affect the stability of the paint layers and disturb the surface of the paintings. Paint cross-sectionsfrom five paintings affected by lead soaps were selected to illustrate and investigate this degradation phenomenon with the analytical imaging techniques of Fourier transform infrared spectroscopy, secondary ion mass spectrometry and scanning electron microscopy combined with X-ray analysis. Examples aregiven of lead soapsforming in a mature paint system or, alternatively, in the early drying stage of the oil; lead soapsforming from various types of lead-containing pigments or driers; lead soapsforming in multiple paint layers; and lead-containing crystallization products inside aggregates. The phenomenon of lead soap aggregatesis multifaceted, and one general scenario describing theformation of lead soap aggregatescannot explain all aspects. However, th...

Corrosion of steel in concrete is a very common degradation phenomenon observed in reinforced concrete structures. It impairs the resisting section of the bars due to the change in the nature of material, the surrounding concrete around the steel bars because of the volume expansion effect of rust and finally modifies the bond between steel and concrete. Some experimental tests are present in literature in which the structural behavior of reinforced concrete beams in presence of corrosion of longitudinal bars and stirrups was analyzed: a progressive reduction of the load bearing capacity was demonstrated with an increase level of corrosion. Furthermore a not-obvious rupture mechanism was observed due to the effect of rust formation; in particular with the increase level of corrosion a change in the type of collapse was observed. In this paper a physical model based on the theory of plasticity is employed in order to explain the residual capacity of corroded beams. The model was developed for sound structures and is able to consider the interaction between shear and bending moment: this aspect is generally neglected following the codes prescriptions for structural evaluation but could become of importance when degradation takes place and determines changes in terms of mode failure. In this model the effect of corrosion is implemented in terms of section reduction and change of basic relationship of steel, degradation of concrete; a comparison with the reliable literature data is performed

In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris var. mongolica trees from two provenances (natural forests and plantations). The results indicated that natural tree needles had lower N, P and C concentrations, and higher K concentrations than those of plantation tree needles. For plantation tree needles, ratios of N: P, P: K and N: K increased with tree age before 45 years old; but they were not clear for the natural tree needles. Compared with the conclusions reported on Pinus spp., we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles. This result suggested that N or P might not be the absolute limit factors in plant nutrient for P. sylvestris var. mongolica on sandy land. However, foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp. (>4.80 g kg-1). The N: P ratio of natural needles was in the adequate ranges, but N: P ratio of plantation needles was out of the adequate ranges. These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations. If only considering the foliar nutrient concentrations of P. sylvestris var. mongolica from different provenances, it might be concluded that the degradation phenomenon of P. sylvestris var. mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P, but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients. The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.

In a stochastic environment, a degradation process, inspite of showing a mono- tone trend, may contain stochastic variations which may camouflage the statistical picture to a certain extent. There are, however, some other processes which may not exhibit a degradation phenomenon. For some of these nondegradation stochas- tic processes, associated aging perspectives are appraised, without being confined to a semiparametric fashion, and their application in health related quality of life assessment are considered.

This paper declares the method for the computation of the wheel-rail surface degradation in a curve where the major surface degradation phenomenon is a combination of wear and plastic deformation. Simulating the form change of the wheel-rail contacts help to identify the risk of severe or catastrophic wear resulting from increased train speeds and axle loads and can help in determining more efficient maintenance schedules for track and rolling stock. The method was previously used to simulate the form change in a two-roller contact. The progress is made in the terms of general geometry modelling, which makes differences in the various contact configurations. The normal contact problem is analysed using the modified Winkler method and calibrated using the results from FEM modelling of the wheel-rail contact with elastic-plastic material model. A piecewise approach and stick-slip analysis of the rolling-sliding contact solves the tangential problem. A linear wear law is used in the wear computation. The form change for a typical two-point contact in a low radius curve was analysed and discussed.

The multiaxial fatigue test under in-phase and out-ofphase load were performed to study what degradation phenomenon affects fatigue life with virgin and 3600 hrs degraded materials. The various kind of fatigue data fur fatigue life prediction were acquired under pure axial and pure torsional load of fully reversal condition. The models which was investigated are: 1) the von Mises equivalent strain range, 2) the critical shear plane approach method of Fatemi-Socie(FS) parameter, 3) the modified Smith-Watson-Topper(SWT) parameter. The result showed that, fatigue life by material degradation are decreased and life prediction which was used the FS parameter is not conservative but the best result.

We review of our theoretical work on various stacking faults in SiC polytypes. Since the discovery of the electronic degradation phenomenon in 4H–SiC p–i–n diodes, stacking faults in SiC have become a subject of intensive study around the globe. At the beginning of our research project, the aim was to find the culprit for the degradation phenomenon, but in the course of this work we uncovered a wealth of information for the general properties of stacking faults in SiC. An intuitive perspective to the diverse nature of stacking faults in SiC will be given in this conference report.

In this study, an investigation for the degradation of p+ to p+ isolation characteristics in a high voltage process with shallow trench isolation was carried out. It could be explained that the degradation phenomenon was caused by carrier injection. In order to improve this, the results of p+ to p+ isolation degradation were determined under different ion implantation conditions and depths and widths of isolation. From these results, it was found that carrier injection mainly occurred at the sidewall of a trench, and the interface trap between Si3N4 and SiO2 was considered to be a dominant factor based on the result of degradation reduction with increasing thickness of sidewall oxide. Consequently, the improvement of the p+ to p+ isolation degradation caused by carrier injection could be achieved by optimizing the dose of a masked lightly doped drain and a field implantation energy.

In-house developed (1– 100) and (11– 20) oriented 4H-SiC wafers, and a reference wafer were used to evaluate the impact of the SiC structural defects on the degradation phenomenon of bipolar pn diodes. Evaluation of the crystal quality and the degraded devices was performed by comparing the results of etch pit densities, electroluminescence, Berg-Barrett topography, HRXRD and HRTEM analysis. Our data demonstrate that the degradation phenomenon is strongly related to the SiC structural crystal defects of the starting material. DENSO (HQ) wafers are less susceptible to the forward current degradation, which we attributed to comparatively much lower etch pit densities, specially the slip/stacking fault defects.