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While experimental explorations to consolidate earthen-site soils using composite materials have obtained desirable reinforcing effect, few modeling efforts were conducted to reveal how microstructures of consolidated soils affect their effective stiffness and strength. The current study develops a multiscale modeling technique to quantify the stiffening and strengthening effects of consolidants to earthen-site soils. Specifically, a micromechanics-based finite element method is applied to simulate the homogenized constitutive relations of the untreated and consolidated soils, based on the microstructures from scanning electron microscopy images and image-processing procedures. Multiscale models are used to examine the influence of input properties of consolidants on the sensitivity of mechanical properties of the earthen-site samples. Comparison between modeling and experimental results shows a satisfactory agreement. The macroscopic mechanical properties of soils are remarkably affected by their microstructures. This study demonstrates the feasibility of integrating scanning electron microscopy and image processing technology into the finite-element modeling for stiffening and strengthening analysis of consolidated earthen-site soils. [ABSTRACT FROM AUTHOR]

• Hydrophobicity arising from PVA changes erosion in different parts of earthen site. • Drying temperature control is a feasible method to eliminate the hydrophobicity. • Soil wettability is a crucial evaluation criterion for protection of earthen sites. • Drying temperature, surface roughness, PVA and water contents affect the wettability. Earthen sites in northwest China represent a precious cultural heritage; however, these sites have been seriously damaged by weathering. Chemical consolidation treatment is a widely accepted conservation method, and PVA solution with a high degree of alcoholysis has exhibited potential for improving the strength of soil. However, research on the influence of the PVA solution on the wettability of these earthen sites is rarely reported. Therefore, the aim of this study is to investigate the change in wettability of earthen sites protected with the PVA by laboratory experiments. First, the compressive strength and wettability of soil specimens are analysed with varying PVA content, water content, and drying temperature. The results indicate that the soil strength and hydrophobicity are highest when the PVA content in the soil is 1.0 wt%. The relationship between the soil hydrophobicity and water content follows a one-peak distribution, whereas the hydrophobicity decreases with increasing in drying temperature and is lost when the drying temperature is 80 °C or more. Second, factors influencing the wettability of the composite soil are discussed, and water vapour permeability of 1 cm thick composite soil is investigated in conjunction with exfoliation of surface crust. Finally, the feasibility of protecting different parts (i.e. the upper, middle, and lower parts) of earthen sites with PVA is briefly discussed, and it is emphasised that the wettability should be considered as crucial evaluation criterion for the protection of earthen sites. [ABSTRACT FROM AUTHOR]

• Hydrophobicity of PVA treated soil decreases after dry–wet and freeze–thaw cycles. • a = 20 is used as the ideal critical value to judge internal wettability. • Wettability of treated soil is mainly controlled by alkyl chain, and hydroxyl group. Earthen sites have important social, historical, artistic, and scientific value. Basal erosion, which is closely related to soluble salt, is one of the most important reasons for the destruction of earthen sites. Soil hydrophobicity may change the path of water–salt migration. Thus, it can protect earthen sites by inhibiting basal erosion at the bottom of earthen walls. However, the changes in the hydrophobicity after freeze–thaw and dry–wet cycles are still unclear. Therefore, the primary aim of this study is to investigate the effects of these cycles on the hydrophobicity of PVA composite soil with a high alcoholysis degree. The results indicate that soil hydrophobicity decreased with increasing number of freeze–thaw and dry–wet cycles. At a dry temperature of 80 °C, the soil lost its hydrophobicity. The surface hydrophobicity of immersed samples dried at room temperature decreased or was lost; however, the hydrophobicity inside samples still remained after five dry–wet cycles. Furthermore, an indicator based on the water inlet velocity was presented to judge the interior wettability. The changes in the wettability of the PVA composite soil were mainly controlled by changes in hydrogen bonds, the coiling and stretching of alkyl chains, and the orientation of free hydroxyl groups. [ABSTRACT FROM AUTHOR]

Static liquefaction can make the loess unstable when the shear stress subjected to a monotonic loading exceeds the undrained peak shear strength of undisturbed saturated loess. It is a phenomenon in the failure of soil deposits caused by a sudden increase of pore water pressure accompanied by large deformations and loss of effective stress that can make soils behave like flowing liquids. In general, the static liquefaction is influenced by confining pressure, microstructure and particle size of the undisturbed loess. The composition and particle size of loess are not easy to be changed, but it is not the case for microstructure during the earthquake. A few scholars focused on the characteristics of static liquefaction when the natural loess was disturbed by pre-dynamic loading. The deviator stress, pore pressure, effective confining pressure of undisturbed loess will respond differently to liquefaction if the loess experienced pre-dynamic loading. This study examined static liquefaction phenomenon in saturated undisturbed loess considering the effects of pre-dynamic loading and confining pressure. Pre-dynamic loading tests with different peak ground acceleration (PGA) showed that the cumulative strain is in the range of 0.019–0.189% under the conditions of PGA = 0.15g, PGA = 0.30 g, PGA = 0.40 g, respectively. Undrained static triaxial compression tests at three different confining pressures (100, 150, and 200 kPa) were implemented on undisturbed loess samples. Static liquefaction was observed at confining pressures of 100 kPa and 150 kPa with different pre-dynamic loadings, and the liquefaction potential of the undisturbed loess decreased with the increases of confining pressure. Loess specimens treated with pre-dynamic loading were easier to liquefy than the samples without pre-dynamic loading treatment. Samples treated with pre-dynamic loading exhibited higher excess pore water pressure than those without pre-dynamic loading treatments. Therefore, the internal friction angle and cohesive force were 5.13%∼15.04% and 26.44%∼82.04% lower than untreated loess. It reveals that the normalization between the maximum and the minimum principal stresses can be used to quantify the liquefaction potential of undisturbed loess. [ABSTRACT FROM AUTHOR]

Hydrogen attack is the major failure cause of hydrogen equipment breakdown maintenance. Especially, common problems like cracks frequently occur but are challenging to find while operating, presenting an issue for safety and production. In the process of hydrogen damage evolution, a method for defect state recognition is proposed in this paper. Acoustic emission (AE) technology is used for inspecting the entire hydrogen charging process. The characteristic parameters including the counts and duration of the AE signals are first preprocessed, and the current damage states such as the dislocation propagation, and the occurrence of cracks are identified. Then, a deep learning convolutional neural network is used to create a hydrogen defect recognition (HDR) model with the input of a short-time Fourier transform for the feature vector extraction of various damage status AE signals. Finally, the hydrogen defect recognition experiment revealed that HDR is better in classification accuracy at 98.37% due to dislocation propagation and cracks identification. The study can provide an online damage recognition approach for damage state early warning and evaluation to guarantee hydrogen equipment safety operation. • Monitor the hydrogen damage process using acoustic emission detection technology. • Characteristics of the acoustic sources in hydrogen damage process are studied. • Neural network is used for hydrogen damage signal recognition and diagnosis. • STFT transform image is used as the neural network model input. [ABSTRACT FROM AUTHOR]

Although nondestructive ultrasonic technologies have been applied in laboratory and field tests in the field of heritage conservation, few studies have quantified the relationship among the real microstructures, micromechanical properties, and macroscopic acoustic responses of earthen-site soils. This paper develops a micromechanics-based multiscale model for quantitatively exploring the ultrasonic propagation characteristics of elastic waves in untreated and consolidated earthen-site soils. Scanning electron microscope images and image processing technology are integrated into the finite-element simulation. The effects of microstructure and wave features on the acoustic characteristics of soils are quantitatively investigated under pulsive loading. The simulation results of untreated and consolidated soils are efficiently compared to ultrasonic test data. It is demonstrated that the integration of microstructure image processing and multiscale modeling can predict the ultrasonic pulse velocity well, which improves the accuracy of laboratory testing and field monitoring and better serves the evaluation and implementation of engineering practice in the field of heritage conservation. [ABSTRACT FROM AUTHOR]

In the study, a three-parameter model was presented to calculate the thermal conductivity at full range of degree of saturation ( S ) for fine-grained soils based on the Fredlund and Xing model and the normalized thermal conductivity method. Three parameters ( a , b , c ) of the new model are determined by two equations and a measured point at a certain S . Two equations were obtained by the correlations between the parameters a , b , c and the basic properties of 30 Canadian soils by regression analysis. Moreover, the relationship between the thermal conductivity and S at full range of S was defined as the thermal conductivity curve (TCC) and was divided into 3 regions for the improvement of the calculation result. According to the sensitivity analysis, it is found that the calculated TCC is the most reliable when a point is measured in the Region 2. In addition, the new calculation model was also verified by 6 Chinese soils, suggesting the new model could present a good calculation result ( R 2  = 0.97) for the TCC. [ABSTRACT FROM AUTHOR]

• The morphology of differential weathering is digitized by 3D laser scanning. • The differential weathering features are characterized by the roughness indexes. • How spatial features of walls affect the differential weathering is discussed. • The classification of differential weathering degree is explored preliminarily. Earthen heritage sites have been undergoing lengthy surface weathering since they were built, which can pose a severe threat to the protection and utilization of these cultural treasures. Especially for differential weathering, one of the most common surface weathering patterns of earthen heritage sites in northwestern China, has not been well studied yet. Hence, in this paper, Suoyang Ancient City was selected as the study area, and six analysis domains (S1 to S6) exhibiting various differential weathering degrees were determined on wall faces and their morphological data were collected by a 3D laser scanner. Based on the point cloud data, the morphology of each domain was digitalized and reconstructed, and ten typical profiles were selected for roughness analysis. Concretely, for these profiles, six roughness parameters, including average asperity inclination (A i), mean curvature (R′da), textural slope parameter (Z 2), roughness coefficient (R p), self-affine fractal dimensions (A and D) and directional roughness metric (G (i)) were calculated to characterize their differential weathering features. The results show that the wall with a higher differential weathering degree has greater values of R p , G (i), A and D. It can also be found that different roughness indicators can reflect different wall surface morphological characteristics. In addition, the main driver of differential weathering developing is the prevailing sediment-laden wind, and the degree of differential weathering is also affected by the building techniques, wall endowment environment, wall orientation and morphology. Finally, according to the roughness values and wall surface morphology, the differential weathering degrees were classified into five grades (from level I to level V). In this case, the differential weathering degrees of S2 (level IV) and S5 (level IV) are the highest, followed by S3 (level III), S6 (level III), S1 (level II) and S4 (level II) respectively. Overall, the proposed approach based on 3D scanning and surface roughness is feasible to characterize the differential weathering degree, contributing to better prevention and mitigation of damage on earthen heritage sites. [ABSTRACT FROM AUTHOR]

In the study, a model matrix, based on the combinations of 1 thermal conductivity model for saturated soils ( λ sat ), 4 thermal conductivity models for dried soils ( λ dry ) and 4 Kersten number models for soils ( K e ), was proposed to calculate the thermal conductivity of soils. 16 calculation models were included in the matrix. The matrix could be used to investigate the effects of the λ dry models and K e models on the calculational results of the 16 calculation models for the thermal conductivity of soils. The matrix was evaluated by 40 Canadian soils, and it is found that the He et al. model for λ dry performs best among the 4 λ dry models, the Côté and Konrad model for K e performs best among the 4 K e models. It also shows that the results of the calculation models in the matrix are different significantly, but the JCM (combination of the geometric mean model for λ sat , the Johansen model for λ dry , and the Côté and Konrad model for K e ) performs best among the calculation models for the thermal conductivity of soils. The effects of the λ dry models and K e models on the calculational results of calculation models for the thermal conductivity were evaluated by the modified difference index (MDI), showing that the K e models have much larger effect on the calculational results than the λ dry models. Besides, the calculation models containing the Côté and Konrad model for K e were recommended to calculate the thermal conductivity of soils for its high accuracy. [ABSTRACT FROM AUTHOR]

This article presents a laboratory and field investigation of pull-out resistance of wood bolts in rammed earth heritages. The laboratory testing involved axial tensile tests of four grout specimens prepared in specially designed moulds using PS-F (Potassium Silicate solution-Fly ash) slurry to investigate the performance of anchors. The field testing involved pull-out tests of three wood anchors installed in rammed earth heritages by gravity grouting. Experiments reveal that the failure mode is the pull-out of bolt from grout and average skin friction resistance of bolt–grout interface is approximately 0.34MPa. Load–displacement curves and elastic–residual displacement derived from cyclic loading indicate such anchor system has strong ductility with small elastic deformation and large residual deformation. Bond collapse firstly occurs at the loaded end and then propagates towards the full bonded length. Bond stress distribution is not uniform along the bonded length. Maximum bond stress distributes at the range from 0.3 m to 0.4 m. Emergence of compressive strain in the interface reveals such anchor system enjoys the advantages of both tensile and compressive anchor types, which significantly differs from results from other regular bolts. The research conclusion makes scientific senses to traditional material and craft in rammed earth heritages. [ABSTRACT FROM PUBLISHER]

A remarkable risk in the field of rock engineering is the natural exposure of low-grade metamorphic rock to the freeze-thaw process. Examples of such materials are slate and phyllite, which are employed approximately mountainous permafrost zones. In order to study the weathering processes and mechanisms in low-grade metamorphic rock following freeze-thaw weathering processes, the freeze-thaw cycles were applied. Accordingly to this process, low-grade metamorphic rock partially or completely deteriorates, and mechanical properties, microstructure, and mineral content changes are commonly associated with freeze-thaw processes. This study shows that, following numerous freeze-thaw cycles processes, the quality, wave velocity, and compressive strength of rock reduce; calcite, mica, feldspar, and pyrite contents decrease; and clay minerals and gypsum content increase. Furthermore, the study also demonstrated that the changes in quality, wave velocity, and compressive strength caused by weathering of the rock followed the sequence slate > phyllite. However, the mineral contents of slate and phyllite alter in the same way. Because of this increase in volume and subsequent F-T cycles, new cracks form on the surfaces of pores due to outward pressure, and a lot of water is absorbed by clay minerals. The amount of water increases once again due to freezing as the temperature falls below zero degrees Celsius. This course duplicates with cyclic temperature changes and causes deterioration of low-grade metamorphic rock materials. By analysis of an examination of the damage variables based on wave velocity, it is possible to conclude that mineral changes during the freeze-thaw effect may make for the formation of voids and the deterioration of metamorphic rock. This research contributes to a better understanding of weathering processes and mechanisms of low-grade metamorphic rock following freeze-thaw weathering processes. [ABSTRACT FROM AUTHOR]

The work reported here is a systematic study to evaluate the compatibility of using PS-F (potassium silicate with high modulus – fly ash) slurry in the conservation of adobe structures. Firstly, the optimum mixing proportion (0.47) was determined by flow meter. Then the experimental program was divided into two parts: one part studied changes in physical and mechanical properties with increase in setting time by means of the measurement of moisture content, compressive and flexural strength, elastic-wave velocity, density, and porosity; the other part studied the durability of PS-F slurry through temperature and humidity cycles, freeze–thaw cycles, water stability, tensile testing, and alkali resistivity tests. The results show that the consolidation process with the slurry can meet the requirements of conservation applications and provide a timely anchoring force, and the slurry and soil mass of adobe-based structures have good compatibility in physical and mechanical properties. In addition, the slurry can strongly resist freeze–thaw cycles, temperature-moisture cycles, and tensile stress and has a relatively weak resistance to alkali solutions and water immersion. In conclusion, PS-F with a mixing ratio of 0.47 is a suitable slurry for conservation of adobe structures. [ABSTRACT FROM PUBLISHER]

Subarachnoid hemorrhage (SAH) is one of the common clinical neurological emergencies. Its incidence accounts for about 5–9% of cerebral stroke patients. Even surviving patients often suffer from severe adverse prognoses such as hemiplegia, aphasia, cognitive dysfunction and even death. Inflammatory response plays an important role during early nerve injury in SAH. Toll-like receptors (TLRs), pattern recognition receptors, are important components of the body's innate immune system, and they are usually activated by damage-associated molecular pattern molecules. Studies have shown that with TLR 4 as an essential member of the TLRs family, the inflammatory transduction pathway mediated by it plays a vital role in brain injury after SAH. After SAH occurrence, large amounts of blood enter the subarachnoid space. This can produce massive damage-associated molecular pattern molecules that bind to TLR4, which activates inflammatory response and causes early brain injury, thus resulting in serious adverse prognoses. In this paper, the process in research on TLR4-mediated inflammatory response mechanism in brain injury after SAH was reviewed to provide a new thought for clinical treatment. [ABSTRACT FROM AUTHOR]

• The development difference of scaling off on the sunward side and nightside of earthen sites was revealed. • The new indicators of salt migration gradient (SMG) and normalized shrinkage rate (NSR) were proposed. • The mechanism of salt difference and heterogeneous shrinkage on different building orientations were indicated. • Environmental monitoring was comprehensively analysed to explain the development difference of scaling off on different building orientations. Scaling off is one of the most representative deterioration types of earthen sites, severely causing their damage with a characteristic binary structure consisting of the crusted and loose layers. Exploring the development cause of scaling off is the key premise for targeted protection of earthen sites. Thus far, numerous researchers focused on environmental and rammed earth factors; however, the development difference of scaling off on different building orientations has not been studied. Therefore, this study aims to reveal the development difference of scaling off on the sunward side and nightside of earthen sites. In this study, 15 earthen sites situated in NW, China, are chosen and the scaling off is investigated in the field to collect characteristic values of the binary structure of scaling off on two sides of the wall. Subsequently, the previous built-up evaluation system is applied to calculate the development degree of scaling off to show its discrepancy rate (DR) on distinct building orientations. Additionally, the samples of rammed earth in different layers are collected and indoor geotechnical tests are performed to obtain the evaluation indicators. Combined with the binary structure and rammed earth properties, the salt differentiation and heterogeneous shrinkage of soils in different layers are quantificationally reflected. Finally, the temperature and humidity of three representative earthen sites are monitored for 24 h after rainfall. By analysing the environmental change, the greater amplitude of environmental change for the sunward side is found; this is an important driving force for salt migration, which leads to the difference in binary structures. This study reveals the development difference of scaling off on the sunward side and nightside from the quantitative perspective, which supplements current research contents on characteristics and mechanism of earthen sites deteriorations, beneficial to their further protection work. [Display omitted] [ABSTRACT FROM AUTHOR]

As a renewable energy source, biomass has the potential to replace non-renewable, fossil fuels. However, the disposal of the waste biomass ash (generated during energy generation) needs to be studied. While prior studies attempted to utilise composite additives containing biomass ash for soil, the introduction of other additives, such as cement, was an environmental burden. By employing biomass ash composition as the sole additive for strengthening purple soil under various curing conditions using high-temperature treatment, this study maximised its utilisation. The results showed that the unconfined compressive strength (UCS) varied across different curing conditions as the biomass ash content increased. After high temperature treatment at 800 ℃, the biomass ash consistently reinforced purple soil under all the curing conditions. However, the biomass ash stabilisation mechanism differed between dry and humid curing conditions. Under dry curing conditions, the UCS increase depended on the cementing effect of soluble salt and/or insoluble calcite; under humid curing conditions, the UCS change was attributed to the damage to clay minerals, contact mode, and cementing effects of multiple components. Therefore, the 800 ℃ temperature-treated biomass ash can be used alone to reinforce purple soil, inhibiting the soil-water loss. This study presents a novel avenue for utilising waste, biomass ash, with considerable implications for environmental protection and soil stabilisation. • Purple soil can be reinforced by biomass ash treated at 800 ℃. • Curing condition has a significant impact on stabilising effect. • Stabilisation mechanisms differ between dry and humid curing conditions. • A novel avenue to utilize waste biomass ash is provided. [ABSTRACT FROM AUTHOR]

Bubble rupture is one of the main acoustic emission (AE) sources for corrosion detection and the study of its acoustic characteristics is of great significance for corrosion identification. However, the stress state affects the form of bubble rupture, causing different acoustic characteristics. In this paper, the acoustic signal characteristics of two forms of bubble rupture and drag phenomena are investigated and the process of bubble rupture both near to and away from the metal surface is studied, mainly through theoretical calculation, numerical simulation and experimentation. A theoretical model of bubble rupture is established according to the volume of fluid (VOF) method. The finite element method is used to solve the plate displacement at the interface. Stress pulse theory is applied to calculate the AE signal amplitude of the bubble rupture. AE source characteristic parameters of the bubble rupture are then proposed. The experimental results demonstrate that the two forms of characteristics of the AE signals from corrosion bubble rupture are consistent with theoretical calculation and simulation results. [ABSTRACT FROM AUTHOR]

Thesinglet oxygen generator (SOG) is the heart of chemical oxygeniodine laser. A new swirl-jet-type SOG was proposed which consistsof a reaction part and a separation part. Planar laser-induced fluorescencecombined with maximum entropy method were used to study the dropletsize distribution, and a modified Muschelknautz model and ComputationalFluid Dynamics were used to simulate the separation efficiency ofvapor and liquid phases. The results of the net reaction predict 99.2%conversion of chlorine and 42.2% yield of singlet oxygen, demonstratingthe superiority of the new type of SOG. [ABSTRACT FROM AUTHOR]

The fatigue behavior of the 800H weld joint at the temperature of 800 °C was investigated, taking into account the effects of residual stress and microstructure. To model the residual stress in the welded joint, a finite element method was employed and its accuracy was verified using a hole drilling method, which was also used to study the evolution of residual stress during cutting and heating processes. Additionally, the weld region was characterized by measuring the distributions of elements and micro-hardness via energy dispersive X-ray spectroscopy and Vickers hardness tester. Fatigue lives, curves of displacement versus the number of cycles were obtained, and the fracture morphology was analyzed. The results reveal that the calculated residual stress in the weld region agrees well with the experimental results, and the transverse residual stress reduces in magnitude due to cutting and heating. Element distribution and micro-hardness exhibit obvious variations from the base metal to the weld metal. The micro-hardness has a minor effect on residual stress but a significant impact on local stress amplitudes at the weld toe. Furthermore, fatigue fractures primarily occur at the weld toe when the maximum cyclic stress exceeds 200 MPa, while the fracture location varies within the middle weld metal under smaller loads. • The low cycle fatigue behavior of 800H weld joint at high temperature of 800 °C is investigated. • The fatigue life of the weld joint is significantly inferior to that of the base metal. • Variations in properties at the weld joint prominently influence the failure location and fatigue life at the weld toe. • The distinction between the low and high fatigue regimes depends on the failure mechanism rather than the number of cycles. [ABSTRACT FROM AUTHOR]

COF LZU-1 has the characteristics of a porous structure, a large specific surface area, and good chemical stability. In recent decades, extensive research has been conducted on its use as a nanomaterial for drug loading and separation. Here, we report a new corrosion inhibitor encapsulated nanostructure (LZU-1 @BTA). We synthesized LZU-1 via a hydrothermal method and loaded benzotriazole (BTA) corrosion inhibitor into LZU-1. The results show that loaded BTA can achieve effective pH-responsive release under acidic and alkaline conditions. The amino group present in the LZU-1 molecule can cross-link with epoxy resin, and its compatibility allows for good dispersion in epoxy resin without any further modification. The LZU-1 @BTA modified epoxy coating has shown remarkable anti-corrosion properties and excellent self-healing capabilities, which have been evaluated through various techniques such as potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), local electrochemical impedance spectroscopy (LEIS), scanning Kelvin probe (SKP) and salt spray testing. The high-quality dispersion of LZU-1 @BTA in the resin, the high cross-linking density, and the pH-responsive release of BTA in the epoxy resin are some of the key factors that contribute to the excellent anti-corrosion performance of the epoxy resin composite coating. This research has opened up new possibilities for designing anti-corrosion coatings with significantly better corrosion resistance. [Display omitted] • COF LZU-1 was used as a multifunctional gatekeeper for benzotriazole. • LZU-1 @BTA was well-dispersed in epoxy resin without any extra chemical modifications. • LZU-1 @BTA notably improved anticorrosion performance for epoxy coating. • LZU-1 @BTA epoxy-coatings exhibited excellent self-healing performance. [ABSTRACT FROM AUTHOR]

Abstract: Large-scale cyclic simple shear tests were conducted on reconstituted specimens of municipal solid waste (MSW) collected from the Tri-Cities landfill in Fremont, California, USA. The influence of waste composition and compacted unit weight on the shear wave velocity, small-strain shear modulus, and strain-dependent shear modulus reduction and damping ratio curves of MSW was investigated in these tests. Modulus reduction and damping ratio curves were evaluated over a strain range of 0.01–3%. Specimens were reconstituted using 100%, 65%, and 35%, by weight, of the material that passed through a 20mm screen and four different levels of compaction effort. All specimens were consolidated under a normal stress of 75kPa prior to testing. The test results show a very strong dependence of shear wave velocity and small strain shear modulus on unit weight. Unit weight also had an influence on modulus reduction and damping ratio. Waste composition had a very strong influence on damping and also influenced shear wave velocity, small strain shear modulus, and modulus reduction. The interrelationship between unit weight and waste composition made it difficult to separate out the effects of these parameters. [Copyright &y& Elsevier]

Earthquakes occur frequently in the Loess Plateau area, which result in damage to loess due to the disturbance of multiple cyclic loading. In this paper, the historical earthquake process is simulated by pre-dynamic loading treatment on undisturbed loess samples. Then cyclic tests are carried out on these treated samples to study the later liquefaction responses with different initial water content. The undisturbed sample is relative to the remold sample instead of the samples without disturbance. Results show that the axial deformation and pore pressure ratio of treated loess samples with initial water content of 5% are larger than those without treatment. For samples with initial water content of 10% and 15%, the cycle number required for liquefaction increases after treatment, but pore pressure ratio is between 0.18 and 0.36, which is less than the 5% water content samples. It means that liquefaction will have been formed before the excess pore pressure increases to large values. Combined with microstructural analysis, it is found that pre-dynamic treatment causes earthquake damage zone in loess with water content of 5%, which results in lower liquefaction stress ratio than non-treated ones. As for samples with water content of 10% and 15%, the internal voids become smaller and fine particles move into the gaps between large particles after treatment, resulting in denser structure which is hard to be liquefied. However, the increasing dynamic stress will aggravate the deterioration of loess at the water content from 5 to 15%. The changes of microstructure of loess samples are vulnerable to the dynamic stress amplitude and water sensitivity. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) decreases the quality of life of the affected individuals. The incidence of PD is expected to increase given the growing aging population. Motor symptoms associated with PD render the patients unable to self-care and function properly. Given that several drugs have been developed to control motor symptoms, highly sensitive scales for clinical evaluation of drug efficacy are needed. Among such scales, the objective and continuous evaluation of wearable devices is increasingly utilized by clinicians and patients. Several electronic technologies have revolutionized the clinical monitoring of PD development, especially its motor symptoms. Here, we review and discuss the recent advances in the development of wearable devices for bradykinesia, tremor, gait, and myotonia. Our aim is to capture the experiences of patients and clinicians, as well as expand our understanding on the application of wearable technology. In so-doing, we lay the foundation for further research into the use of wearable technology in the management of PD. [ABSTRACT FROM AUTHOR]

Owing to man-made activities and natural conditions, the groundwater table experiences considerable changes in Lanzhou. Centrifugal model tests were performed to investigate the settlement of strip footings on loess subject to rising water table under different foundation pressures. The air-fall method was employed to reconstitute the artificial loess samples. The applicability of the air-fall prepared samples was evaluated against the parameters of the undisturbed loess samples obtained from the same location. The results of centrifuge tests reveal that the footing settlement increases significantly with increasing foundation loading pressure or increasing rising water table. However, the rate of increase in ultimate footing settlement under combined rising water level and footing pressure is established to be more intriguing. A simplified method for predicting the ultimate footing settlement on collapsible loess due to rising water table height is proposed. The proposed formulation is verified, as there is a good agreement between the test results under various loading pressures and rising water heights and the predicted ultimate footing settlements. A discussion on the ultimate settlement of strip footings subjected to rising water table against conventional bearing capacity safety factors is presented to provide some basis for the foundation design consideration under rising water scenario. [ABSTRACT FROM AUTHOR]

A correction to the article "The electronic structure of MoC and WC by anion photoelectron spectroscopy" that was published in the 2008 issue is presented.

The vacuum ultraviolet pulsed field ionization-photoelectron (PFI-PE) spectra for CO[sub 2] have been measured in the energy range of 13.6-14.7 eV, revealing complex vibronic structures for the ground CO[sub 2][sup +](X [sup 2]Π[sub g]) state. Many vibronic bands for CO[sub 2][sup +](X [sup 2]Π[sub g]), which were not resolved in previous photoelectron studies, are identified in the present measurement based on comparison with available optical data and theoretical predictions. As observed in the HeI photoelectron spectrum of CO[sub 2], the PFI-PE spectrum is dominated by the symmetry allowed ν[sub 1][sup +] (symmetric stretch) vibrational progression for CO[sub 2][sup +](X [sup 2]Π[sub g]). However, PFI-PE vibronic bands due to excitation of the symmetry disallowed ν[sub 2][sup +] (bending) and ν[sub 3][sup +] (asymmetric stretch) modes with both odd quanta, together with the symmetry allowed even quanta excitations, are clearly discernible. The simulation of rotational contours resolved in PFI-PE vibronic bands associated with excitation to the (ν[sub 1][sup +]=0-1, ν[sub 2][sup +]=0-2, ν[sub 3][sup +]=0) vibrational levels has yielded accurate ionization energies for the formation of these vibronic states from CO[sub 2](X [sup 1]Σ[sub g][sup +]). © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Using the high-resolution pulsed field ionization-photoelectron (PFI-PE) and PFI-PE-photoion coincidence (PFI-PEPICO) techniques, we have examined the formation of methyl cation (CH[sub 3][sup +]) from the dissociation of energy-selected CH[sub 3]X[sup +] (X=Br and I) near their dissociation thresholds. The breakdown diagrams for CH[sub 3]X thus obtained yield values of 12.834±0.002 eV and 12.269±0.003 eV for the 0 K dissociative threshold or appearance energy (AE) for CH[sub 3][sup +] from CH[sub 3]Br and CH[sub 3]I, respectively. Similar to the observation in PFI-PE studies of CH[sub 4], C[sub 2]H[sub 2], and NH[sub 3], the PFI-PE spectrum for CH[sub 3]Br exhibits a step at the 0 K AE for CH[sub 3][sup +], indicating that the dissociation of excited CH[sub 3]Br in high-n (>=100) Rydberg states at energies slightly above the dissociation threshold occurs in a time scale of ≤10[sup -7] s. The observed step is a confirmation of the 0 K AE(CH[sub 3][sup +]) from CH[sub 3]Br determined in the PFI-PEPICO study. The adiabatic ionization energies (IEs) for the CH[sub 3]Br[sup +](X˜ [sup 2]E[sub 3/2,1/2]) spin–orbit states were determined by PFI-PE measurements to be 10.5427±0.0010 and 10.8615±0.0010 eV, respectively, yielding the spin–orbit coupling constant to be 2571±4 cm-1. The AE(CH[sub 3][sup +]) values from CH[sub 3]Br and CH[sub 3]I and the IE[CH[sub 3]Br[sup +](X˜ [sup 2]E[sub 3/2])] value obtained here, when combined with the known IE of CH[sub 3] (9.8380±0.0004 eV) and IE[CH[sub 3]I[sup +](X˜ [sup 2]E[sub 3/2])] (9.5381±0.0001 eV), have allowed accurate determination of the 0 K bond dissociation energies for CH[sub 3]–Br (2.996±0.002 eV), CH[sub 3][sup +]–Br (2.291±0.002 eV), CH[sub 3]–I (2.431±0.003 eV), and CH[sub 3][sup +]–I (2.731±0.003 eV). Using the AE(CH[sub 3][sup +]) from CH[sub 3]Br and CH[sub 3]I, together with the known 0 K he... [ABSTRACT FROM AUTHOR]

Coastal loess is a special loess deposit that is distributed around the Bohai Sea. The primary objective of this study was to investigate the physical index, mineralogical characteristics and collapse potential of coastal loess. The secondary objective was to survey the effect of fine silt particles (particle size 5–10 μm, 6.64–7.64φ) on the collapse process. We tested the specific gravity, moisture content, dry density, Atterberg limits, grain size distribution, mineralogy, and collapsibility characteristics in a laboratory; generated scanning electron microscopy (SEM) images; and performed Mercury intrusion porosometry (MIP) tests. The results of this investigation indicated that coastal loess has a moderately severe collapse potential. The collapsibility coefficient decreases with an increase in the initial water content; it initially increases and then decreases with an increase in vertical pressure. As revealed by the MIP test, the collapse produces a smaller porosity, and the middle pores are primarily responsible for the collapse. The relationship of the collapsibility coefficient and particles with a diameter < 10 μm reveals that fine silt particles (particle size 5–10 μm, 6.64–7.64φ) and clay particles (particle size < 5 μm, >7.64φ) have the same tendency in terms of their effect on collapse. These results and analyses are important to improve the engineering construction safety in coastal zone loess areas and achieve a better understanding of loess properties compared with loess from a typical loess-paleosol section. • Surveyed the particle and pore size distribution, Atterberg limits and mineralogical characteristics of Coastal loess. • Obtained the collapsibility of Coastal loess, and proposed the relationship between collapsibility coefficient and micro indexes based on the results of SEM and MIP tests. • Discussed the effect of fine silt particles (5-10 μm) on the collapse process. [ABSTRACT FROM AUTHOR]

• The morphological characteristics of BSCs on the earthen sites were analyzed. • We obtained the mechanical properties of BSCs on the earthen sites. • The research strategy to determine the effect of plant development in the surface layers of the earthen sites was proposed. Earthen sites are cultural and have rich historical significance. However, most earthen sites have been damaged or even destroyed during historic preservation. To reduce the damage caused by rain, snow erosion, freezing and thawing, these sites should be protected using vascular plant capping technology, which has great research value and application prospects. However, the effect of biological soil crusts (BSCs) on the shallow surfaces of these sites is scarcely understood. Therefore, this study aimed to explore the soil consolidation characteristics of BSCs on the shallow surfaces of earthen sites through laboratory experiments. First, the species, morphology and geometric characteristics of BSCs were studied using observation with a high–resolution digital microscope and analyses of the fractal and topological dimensions of rhizoids. The results showed that the dominant population of BSCs was composed of Didymodon vinealis , and the rhizoid type exhibited herringbone architecture. In addition, the effect of rhizoid anchoring was greater than that of rhizoid wedging. Second, the mechanical properties of the soil consolidation of the rhizoid–soil composite were investigated using tensile strength tests of single rhizoids and shear strength tests of rhizoid–soil composites. It was concluded that moss rhizoids could improve the shear strength of the surface soil. Additionally, the surface roughness of the rhizoids affected their anchorage characteristics. Finally, we discussed the disadvantages of generally classifying plants as "potentially harmful", and emphasized the necessity of constructing a heterogeneous research model highlighting specific environmental factors, plants, and earthen sites. [ABSTRACT FROM AUTHOR]

This study examines the small-strain stress-strain properties during cyclic loading of Lanzhou loess deposits, characterized by a very high void ratio (>0.9). Torsional resonant column (RC) tests are performed in order to investigate the effect of water content, confining pressure, consolidation time and soil structure strength on the small-strain stiffness ( G 0 ) and damping (D min ) of loess. It is proved that shear modulus G 0 at low strain levels is very sensitive to water content while the effect of water content on small-strain damping D min is relatively small. As water content W approaches the plastic limit PL, there is a dramatic decrease of G 0 compared to drier loess specimen; G 0 has the tendency to reach a stable or constant value with further increase of water content which is more than the PL of loess. The small strain damping D min decreases continuously with water content for unsaturated loess and then tends to increase slightly for almost fully saturated loess. A linear relationship between G 0 and confining pressure σ′ m in log-log coordinates for different water contents is observed for Lanzhou loess. Similarly, D min decreases linearly with σ′ m . A power function is proposed to describe the relationship between G 0 and confining pressure σ′ m where the exponent m varies with the water content of loess. G 0 is also affected by the consolidation duration and a power function is proposed between normalized G 0 and normalized consolidation time. G 0 is finally strongly affected by the structure of loess and the type of specimen. For undisturbed loess samples, G 0 is always higher than reconstituted ones and the difference decreases with the degree of saturation; for fully saturated samples the influence of the structure strength between undisturbed and reconstituted samples becomes insignificant. Likewise, D min of undisturbed loess is higher than that for remolded loess under the same confining pressure and the difference between them reduces with the degree of saturation as well. [ABSTRACT FROM AUTHOR]

Loess is a kind of world-recognized problematic soil and, as a consequence, it is a major hazard in geotechnical engineering. This study examines the small to medium strain dynamic properties of Lanzhou intact and recompacted loess through a set of resonant column (RC) tests. The influence of soil structure on the small-strain shear modulus G 0 , the variations of G / G 0, and damping ratio DT(%) with shear strain γ were analyzed and discussed. The test results show that the structure has an important influence on the dynamic properties of dry loess at small and medium strain, whereas, with the increase of moisture, its effect weakens. It is proved that a normalized correlation between G / G 0 and γ/γ 0.7 is practically identical for undisturbed and recompacted loess in Lanzhou, irrespective of soil structure, which may be useful in practical applications. • The small to medium strain dynamic properties of Lanzhou loess with metastable structure were examined. • Structure effect reduces the ductility in dynamic response for Lanzhou loess. • The correlations between G / G 0 and γ/γ 0.70 could be normalized well for Lanzhou loess, irrespective of structure effect. [ABSTRACT FROM AUTHOR]

The mechanism of dissolving acoustic source of Q235B corrosion anode metal is the basis of acoustic emission (AE) source identification and corrosion site evaluation and analysis. In this paper, the local mechanical energy release and the characteristics of radiated elastic wave pulse in the process of metal dissolution are analyzed by using the principles of corrosion dynamics, damage thermodynamic energy conversion, local mechanical energy release and radiation elastic wave pulse characteristics of metal dissolving process, and the theoretical analysis is verified by atomic first numerical method. Combined with AE and electrochemical testing technology, the mechanism of Q235B steel corrosion acoustic source is studied experimentally. The characteristics of the metal dissolved acoustic source are obtained, and the energy conversion value of anode metal in the process of dissolution is extracted. The quantitative characterization formula of the corrosion behavior of the AE is established, which provides a basis for the assessment of the severity of the corrosion state of Q235B steel. • Under the action of electrochemical driving force, the breakage of crystal bonds triggered by the metal atoms leaving the lattice and the jumping mechanical motion of metal atoms in the phase boundary region are accompanied by the radiation of elastic wave pulses, forming the AE source. • The numerical results of the energy released by atoms during corrosion are obtained using atomic first nature numerical calculations. Dissolution of anode metal can be used as the basis for AE detection of Q235B steel corrosion. • A quantitative characterization formula of the corrosion behavior of the AE is established, which provides a basis for the assessment of the severity of the corrosion state of Q235B steel. [ABSTRACT FROM AUTHOR]

Adipose tissue not only affects meat quality and animal productivity, but also participates in inflammation and immunity. Ningxiang pig is famous for their excellent meat quality, disease resistance and tolerance of roughage. It is not yet well known how proteins in adipose tissue is dynamically regulated during the growth of Ningxiang pig. This report studies the proteomic changes in subcutaneous adipose tissue in Ningxiang pigs to gain a better understanding of the molecular mechanism of fat development during the growth period. By TMT-labeled quantitative proteomic analysis of subcutaneous adipose tissue of 9 purebred Ningxiang pigs of different ages, we identified 2533 unique proteins and 716 differentially abundant proteins (DAPs), of which more than half of the DAPs were concentrated in the 90d-210d period. Retrograde endocannabinoid signaling was only significantly enriched in DAPs of N90d vs N30d, Alcoholism and Graft-versus-host disease were only significantly enriched in DAPs of N210d vs N90d. Proteins related to dilated cardiomyopathy was found to be an important pathway in fat development and lipid metabolism. A variety of novel DAPs involved in maintaining mitochondrial function and cell viability, such as NDUFS6, SDHB, COX5A, ATP5D and TNNT1, which play a role in controlling the prediction networks, may indirectly regulate the development and functional maintenance of adipocytes. These age-dependent DAPs discovered in this study may help expand the understanding of the molecular mechanisms of the development, function maintenance and transformation of adipose tissue in Ningxiang pig for developing new strategies for improving meat quality and pig breeding in the future. [Display omitted] • By proteomic analysis of adipose tissue, this study identified 2533 unique proteins and 716 DAPs in the growth period of Ningxing pigs; • DAPs related to dilated cardiomyopathy is distinguished as an important enrichment pathway in pig adipose tissue; • A variety of novel DAPs for maintaining mitochondrial function and cell viability such as NDUFS6, SDHB, COX5A, ATP5D and TNNT1 plays a key role in pig adipose tissue development and energy balance. [ABSTRACT FROM AUTHOR]

In this study, we examined the effect of progesterone on histopathologic and functional outcomes of intracerebral hemorrhage (ICH) in 10- to 12-month-old mice. Progesterone or vehicle was administered by intraperitoneal injection 1 hour after collagenase-induced ICH and then by subcutaneous injections at 6, 24, and 48 hours. Oxidative and nitrosative stress were assayed at 12 hours post-ICH. Injury markers were examined on day 1, and lesion was examined on day 3. Neurologic deficits were examined for 28 days. Progesterone posttreatment reduced lesion volume, brain swelling, edema, and cell degeneration and improved long-term neurologic function. These protective effects were associated with reductions in protein carbonyl formation, protein nitrosylation, and matrix metalloproteinase-9 activity and attenuated cellular and molecular inflammatory responses. Progesterone also reduced vascular endothelial growth factor expression, increased neuronal-specific Na + /K + ATPase ɑ3 subunit expression, and reduced protein kinase C–dependent Na + /K + ATPase phosphorylation. Furthermore, progesterone reduced glial scar thickness, myelin loss, brain atrophy, and residual injury volume on day 28 after ICH. With multiple brain targets, progesterone warrants further investigation for its potential use in ICH therapy. [ABSTRACT FROM AUTHOR]

To verify the applicability and superiority of the compressible filtered mass density function method in real supersonic mixing flows, a classical experimental subsonic-supersonic spatial mixing layer is numerically investigated. In the present method, a transport equation for the scalar filtered mass density function is solved using the Lagrangian particle solver, while the filtered mass, momentum, and energy equations are fully coupled and solved by the large eddy simulation finite difference solver. First, a parametric study of the mixing model constant controlling the scalar mixing rate is conducted in the two-dimensional case. It is found that the mixing model constant has a significant effect on the root mean square profile of the mixture fraction. The appropriate mixing model constant for this supersonic mixing layer is given by comparing the root mean square results under three different mixing model constants. These results also show that the suitable mixing model constant used in compressible flows is much larger than that used in incompressible flows. Second, three-dimensional simulations are performed to verify the current method. For comparison, a traditional large eddy simulation with the gradient diffusion model is also conducted. The results show that the scalar mixing is better predicted by the filtered mass density function method than the gradient diffusion model. In particular, the mean and root mean square mixture fraction computed by the present method are in excellent agreement with the experimental data whereas the gradient diffusion model overestimates the peak root mean square mixture fraction by about 45%. [ABSTRACT FROM AUTHOR]

Two scale-model tests were separately conducted in standard Toyoura sand with relative density of 50% and 80%. The effect of sand relative density on pile-soil interaction was investigated through the response of a laterally loaded pile and the sand movement around the pile. At a displacement of 3.6 mm of the loading point, the applied loads in loose and dense sand were 4.775 N and 21.025 N, respectively, and the maximum moment and soil resistance of the pile in dense sand were over 4 times those in loose sand. However, the deflection of the pile in dense sand was less than that in loose sand; additionally, the depth of zero deflection in dense sand was also less than that in loose sand. At the same time, the maximum displacements of loose sand in the vertical profile and ground surface were over 1.5 times those of dense sand. These characteristics occurred because the relative stiffness ratio of soil and pile increased as the relative density increased, which caused the behavior of the pile in dense sand to be elastic rather than rigid. In addition, the compacted sand particles did not move as easily as the loose sand particles. [ABSTRACT FROM AUTHOR]

Abstract: A series of ring-shear tests was conducted on saturated loess to investigate the effects of NaCl concentration in pore water and desalinization on the shear behavior under undrained conditions. The loess samples were taken from the ground surface of a frequently active landslide in China, were saturated by de-aired, distilled water with different concentrations of NaCl, and then were sheared undrained. After that, the samples were retrieved, remolded, re-set into the shear box, and re-saturated by passing through de-aired, distilled water such that the samples were desalinized, and then were sheared undrained again. Through comparing the undrained shear behavior, the effects of NaCl in the pore-water and desalinization on the undrained shear behavior of loess were examined. The results showed that the variation of NaCl concentration in pore water can strongly affect the shear behavior of saturated loess. Both the peak shear strength and steady-state strength increased with increase of NaCl concentration until a certain value, after which they decreased with further increase of NaCl concentration. Meanwhile, the peak shear strength and steady-state strength of the desalinized samples recovered to those of the original sample; hence, the effects of salinization are reversible. These findings may be of practical importance to better understand the repeated occurrence of some irrigation-induced loess landslides in China. [Copyright &y& Elsevier]

We have examined the titled reaction near its threshold using the pulsed field ionization photoelectron–photoion coincidence method. The measured 0 K threshold (18.220±0.002 eV) has made possible the determination of more precise values for the 0 K bond dissociation energies for D–OD+ (5.584±0.002 eV) and D–OD (5.191±0.002 eV) and the 0 K heats of formation (ΔH0f0''s) for OD+ (308.83±0.05 kcal/mol) and OD (8.38±0.05 kcal/mol). We found that the available energetic data for the OD/OD+ and D2O/D2O+ system are in excellent agreement with those for the OH/OH+ and H2O/H2O+ system after taking into account the zero-point vibration energies of these species. [Copyright &y& Elsevier]

We developed and validated a prediction score for predicting the probability of 6-month and 12-month seizure freedom of antiepileptic drug (AED) treatment in newly diagnosed patients with magnetic resonance imaging (MRI)-negative epilepsy. The development cohort included 543 consecutive patients from the Epilepsy Center of Henan Provincial People's Hospital, while the validation cohorts included 493 consecutive patients in two independent cohorts. Univariate analysis and a forward and backward elimination of multivariate Cox regression analysis were used to select predictive factors. The performance of the score was evaluated with C-index, calibration plots, and decision curve analysis. The risk stratification was also performed. The score included five routinely available predictors including Circadian rhythms, Electroencephalography before AED treatment, Neuropsychiatric disorders, Perinatal brain injury, and History of central nervous system infection (CENPH score). When applied to the external validation cohort, the score showed good discrimination with C-index (development group: 0.83; validation group: 0.78), and calibration plots indicated well calibration, as well as the decision curve analysis showed good predictive accuracy and clinical values in four cohorts. The points of the score were categorized to the following three probability levels for predicting seizure freedom: high probability (0–83.11 points), medium probability (83.11–122.71 points), and low probability (> 122.71 points). And online calculator was established to make this score easily applicable in clinical practice. We established a simple, practical, and evidence-based prediction score for predicting seizure freedom with AEDs to aid in the clinical consultation and treatment decision for the newly diagnosed patients with MRI-negative epilepsy. • A score was established based on identified five predictors, which can be used to predict the 6-month and 12-month probability of seizure freedom with AEDs. • The score was validated in two external centers and showed good discrimination, calibration and usefulness. • A web-based calculator was also established; the points of the score can be categorized to three levels. [ABSTRACT FROM AUTHOR]

• 2,5-Diphenylfuran was used as chemical trap to indirectly detect 1O 2 in ILs. • First order rate constants for 1O 2 quenching were determined by UV–vis spectroscopy. • The effects of ILs on rate constants of quenching and 1O 2 lifetimes were explored. 2,5-Diphenylfuran was used as chemical trap for indirect detection of singlet oxygen (1O 2) in ionic liquids (ILs). 1O 2 was generated by photosensitization of Rose Bengal and the first order quenching rate constants of 1O 2 were determined by UV–vis spectroscopy. The effects of the ILs structure on the rate constants were discussed. Furthermore, the generation of 1O 2 in ILs was directly confirmed by means of the time-resolved NIR emission spectroscopy. The correlations between 1O 2 lifetimes and the rate constants of 2,5-diphenylfuran quenching were elucidated, from perspectives of cationic and anionic structure of ILs, respectively. [ABSTRACT FROM AUTHOR]

Employing the newly developed high-resolution pulsed field ionization-photoelectron (PFI-PE)-photoion coincidence (PFI-PEPICO) technique, we have examined the dissociation of energy-selected NH[sub 3][sup +] to form NH[sub 2][sup +]+H near its threshold. The breakdown curves for NH[sub 2][sup +] and NH[sub 3][sup +] thus obtained yield a value of 15.765±0.001 eV for the 0 K dissociation threshold or appearance energy (AE) for NH[sub 2][sup +] from NH[sub 3]. This value, together with the known ionization energy (IE=10.1864±0.0001 eV) and 0 K bond dissociation energy (D[sub 0]=4.6017±0.0025 eV) for NH[sub 3], allows the determination of the D[sub 0](NH[sub 2][sup +]–H) and IE(NH[sub 2]), which are 5.5786±0.0010 and 11.1633±0.0025 eV, respectively. Using the known 0 K heats of formation (ΔH[sub f0][sup °]) for NH[sub 3] and H and the AE(NH[sub 2][sup +]), we obtain the ΔH[sub f0][sup °](NH[sub 2][sup +])=302.60±0.08 kcal/mol. The PFI-PE spectrum for NH[sub 3] exhibits a step-like feature at the 0 K AE(NH[sub 2][sup +]), indicating that the dissociation of excited NH[sub 3] in high-n (n>=100) Rydberg states at energies slightly above the dissociation threshold occurs on a time scale ≤10[sup -7] s. This step confirms the AE(NH[sub 2][sup +]) value derived from the PFI-PEPICO measurements. Highly accurate energetic data with well-founded error limits, such as those obtained in the present and other studies using the PFI techniques, are expected to play an important role for the development of the next generation of ab initio quantum computation procedures. This experiment has stimulated a state-of-the-art ab initio quantum chemical calculation [Dixon et al., J. Chem. Phys. 115, 2576 (2001)]. The comparison between theoretical predictions and the best experimental results for the NH[sub 2]/NH[sub 2][sup +] and NH[sub 3]/NH[sub 3][sup +] systems indicates that the accuracy of the computational scheme used ... [ABSTRACT FROM AUTHOR]