Instrumented Section Research Articles

Void fraction measurement in steam–water two-phase flow using the gamma ray attenuation under high pressure and high temperature evaporating conditions

The void fraction is one of the most important parameters used to characterize gas–liquid two-phase flow, and a myriad of researchers have investigated it under the adiabatic flow conditions. The gamma ray attenuation is a frequently used non-intrusive method for measuring component volume fraction in gas–liquid two-phase flow system. In this paper, firstly, the influence of the various parameters and test conditions on the gamma ray attenuation have been completely examined, such as the calibration of Count Rate for pure gas and liquid phases, the influences of fluid temperature, phase changing point and fluid mass velocity, distance between gamma ray attenuation measuring instrument and experimental section etc. Secondly, the measurement of void fraction was taken in the vertically upward pipes under high pressure and high temperature evaporating conditions. The experimental results of void fraction were compared with the data in reference literature for measurement, the results from the gamma ray attenuation show good agreement with the literature for air–water two-phase flows, but for the evaporating conditions, a small number of compared data beyond the statistical approach for 90% of confidence interval due to some reasons, such as heat flux, the diameter of Taylor-bubbles, longitude of slugs etc. Finally, six predicted correlations from four groups were selected for comparing with the experimental data. The most of compared data were within the statistical approach for 85% of confidence interval. In general, the void fraction was rarely investigated and the available data was limited under high temperature and high pressure evaporating conditions. The investigations of present study are helpful to resolve the difficulties of measuring for gas–liquid two-phase flows concerning to the heated evaporating condition.

Enhancing Rutting Prediction of the Mechanistic–Empirical Pavement Design Guide by Using Data from a Field Test Section in Oklahoma

An instrumented test section was constructed on Interstate 35 near Purcell, Oklahoma. Mechanistic–Empirical Pavement Design Guide (MEPDG) input parameters for traffic, climate, and materials were developed from the data for this test section. The site included a weigh-in-motion station and lateral positioning sensors to obtain input parameters for traffic. In addition, laboratory tests—dynamic modulus, resilient modulus, dynamic shear rheometer, and other pertinent tests—were conducted with materials from the test section. Rut measurements were taken at the site on a quarterly basis for 5 years. Differences in traffic input parameters between Level 3 and Level 1 were identified and are discussed in this paper. At first, significant differences were observed between measured and predicted ruts. For example, the average error between the MEPDG-predicted rut and the measured rut was approximately 18% when default input parameters were used. Although the average error was reduced to approximately 10% when the Level 1 inputs were used, differences between the predicted and measured ruts still existed, which necessitated the development of local calibration factors. After the calibration process, the average error was reduced to less than 5%. The optimized calibration coefficients were found to be β r1 = 2, β r2 = 1, and β r3 = 0.9 for asphalt layers; βGB = 1 for an aggregate base layer; and βSG = 0.5 for a natural subgrade layer. There is a need for the development of a database and local calibration of models for successful implementation of the MEPDG in Oklahoma.

Score-Informed Source Separation for Multichannel Orchestral Recordings

This paper proposes a system for score-informed audio source separation for multichannel orchestral recordings. The orchestral music repertoire relies on the existence of scores. Thus, a reliable separation requires a good alignment of the score with the audio of the performance. To that extent, automatic score alignment methods are reliable when allowing a tolerance window around the actual onset and offset. Moreover, several factors increase the difficulty of our task: a high reverberant image, large ensembles having rich polyphony, and a large variety of instruments recorded within a distant-microphone setup. To solve these problems, we design context-specific methods such as the refinement of score-following output in order to obtain a more precise alignment. Moreover, we extend a close-microphone separation framework to deal with the distant-microphone orchestral recordings. Then, we propose the first open evaluation dataset in this musical context, including annotations of the notes played by multiple instruments from an orchestral ensemble. The evaluation aims at analyzing the interactions of important parts of the separation framework on the quality of separation. Results show that we are able to align the original score with the audio of the performance and separate the sources corresponding to the instrument sections.

Attentional flexibility and memory capacity in conductors and pianists.

Individuals with high working memory (WM) capacity also tend to have better selective and divided attention. Although both capacities are essential for skilled performance in many areas, evidence for potential training and expertise effects is scarce. We investigated the attentional flexibility of musical conductors by comparing them to equivalently trained pianists. Conductors must focus their attention both on individual instruments and on larger sections of different instruments. We studied students and professionals in both domains to assess the contributions of age and training to these skills. Participants completed WM span tests for auditory and visual (notated) pitches and timing durations, as well as long-term memory tests. In three dichotic attention tasks, they were asked to detect small pitch and timing deviations from two melodic streams presented in baseline (separate streams), selective-attention (concentrating on only one stream), and divided-attention (concentrating on targets in both streams simultaneously) conditions. Conductors were better than pianists in detecting timing deviations in divided attention, and experts detected more targets than students. We found no group differences for WM capacity or for pitch deviations in the attention tasks, even after controlling for the older age of the experts. Musicians' WM spans across multimodal conditions were positively related to selective and divided attention. High-WM participants also had shorter reaction times in selective attention. Taken together, conductors showed higher attentional flexibility in successfully switching between different foci of attention.

Back Analysis of Rock Mass Displacements Around a Deep Shaft Using Two- and Three-Dimensional Continuum Modeling

An instrumented section of a 10-m-diameter circular shaft located at a depth of 1.2 km in an average quality rock mass was back analyzed to establish the rock mass behavior. Extensometers were installed radially at four locations and provided the primary data for the back analyses. Three- and two-dimensional continuum models were analyzed using the numerical codes FLAC3Dand Phase2 to assess the rock mass behavior. An initial set of mechanical parameters obtained from empirical relationships were found to give a reasonable match to the measured response of extensometers 2 and 4, when using a Mohr–Coulomb strain softening model. A different set of parameters were needed for FLAC3D when trying to match the significantly higher displacements recorded by only one of the extensometer. It was noted that regardless of the material model and corresponding parameters, the three-dimensional models were not able to give reasonable match to the results of all extensometers. It was shown that for the given problem, there is a theoretical limit for ratio of displacements predicted for different extensometers using a continuum isotropic material model. The two-dimensional models in Phase2, however, gave an apparently better overall match to all the extensometers. Comparison of the results of three-dimensional models with the assumed longitudinal displacement profile for the two-dimensional model indicated that the three-dimensional effects were not adequately captured in the two-dimensional model.

Development of Rut Prediction Models from an Instrumented In-Service Test Section on Interstate-35

This paper presents development of two different field rut prediction models based on data collected from an instrumented pavement section on I-35 in McClain County, Oklahoma. Two rut prediction models, vertical strain-based (VSB) and shear strain-based (SSB), were developed utilizing four years of pavement and environmental data and from approximately 18.7-million accumulated axles. The VSB model considers vertical strain on the top of the aggregate base layer, while the SSB model was based on the shear strain in the Hot Mix Asphalt (HMA) layer. Falling Weight Deflectometer (FWD) tests were conducted over a wide range of temperature to establish modulus and temperature relationship. A pavement analysis software, WinJULEA, was used to develop correlations between temperature and vertical and shear strains for single and tandem axles. In addition, field rut measurements were conducted periodically using a straight edge-rut gauge combination and a Face Dipstick^®. A systematic methodology to develop the rut prediction models is presented in the paper. The correlation coefficient (R^2) for the VSB and the SSB models were found to be 0.78 and 0.72, respectively. Statistical analyses showed that both models predicted rut with a similar level of accuracy. The results from this study are expected to be useful in predicting rut of state highway pavements under similar traffic and environmental conditions. In addition, data collected from this study may be used for local calibration of rut prediction model available in the Mechanistic-Empirical Pavement Design Guide (MEPDG).

Acoustical quality in concert halls as related to hall shape: Shoebox, surround, and other.

(ProQuest: ... denotes formulae omitted)This article examines objective acoustical differences and the spread of acoustical quality among shoebox, nonshoebox, and surround concert This study was motivated by frequent remarks by listeners that there is a greater difference in sound quality depending on the seat locations in nonshoebox halls than in shoebox halls.Here, shoebox halls (SB) are defined as rectangular with the audience seating so configured that large areas of upper sidewalls are available for around-the-hall high-up reverberation (Figure 1a). Parenthetically, in these halls the orchestra is always located at one end. Nonshoebox halls (NSB) are those so configured that at least one sidewall (or rear wall) is mostly covered by audience seating, thus eliminating the possibility of high-up around-the-hall reverberation (Figure 1b). Surround halls (SR) are those in which the audience seating clearly surrounds the orchestra (Figure 1c). The podium is nearer to the center than in traditional SB Typically about half of the audience is seated in several rows that surround the orchestra. In all parts of the hall, the seating is often divided into smaller groups that resemble vineyard steps.The surround-shaped hall originated with the Berlin Philharmonie Hall, in which the architect postulated freer communication between the audience and the musicians (Beranek, 2004, pp. 297-300; Jones, 1989; Lanier, 1964). Also, in most surround halls, around-the-hall high-up reverberation is limited. The different shapes of the halls create variations in several acoustical characteristics which can be heard by experienced listeners. These characteristics include at least: (a) reverberant sound in the upper reaches of a hall, (b) arrival times and number of early lateral reflections, (c) the magnitude of the change in acoustical quality with seat location, and (d) the variation in the balance of sounds between the different sections of the orchestra depending on seat location. Sometimes also cited is Togetherness, the feeling of acoustical intimacy between performers and audience.The shoebox (SB) shape is the geometry that is most likely to be judged as having excellent acoustical quality (Beranek, 1996, Appendix 3; Beranek, 2004, pp. 499-500; Beranek, 2014; Winckel, 1967). The composers of the Classical and Romantic periods of orchestral music created their works largely for performance in SB. Architects and building owners know this but have gone to these other shapes, NSB and SR, largely to create unique architectural designs, and often to decrease the sightline distances between performers and listeners.Meyer (2011) showed that SB and SR halls have been most frequently built after 2000, based on his classification of shapes of 160 concert halls constructed from 1960 to 2010. In relation to the hall shape, he emphasizes the importance of the dynamic balance between the different instrument sections as well as the seating arrangement of orchestra, which he says is very important. He pointed out that for some people architectural innovation seems to be more important than excellent acoustics.After Beranek (personal communication, January 28, 2015), Acoustic Quality is a term often used by acousticians to compare the sound of symphonic music as heard at a seat in a concert hall with that heard at an equivalent seat in the world's older highestrated shoebox-shaped concert halls. This term is also used for opera houses and chamber music halls (Hidaka & Beranek, 2000; Hidaka & Nishihara, 2004; Kahle, 2013). Beranek and one of the authors (Hidaka & Beranek, 2010) also studied the acousticalquality spread from seat to seat relating to the hall shape: shoebox, nonshoebox, and surround. Based on his definition (Beranek, 1996, p. 520) that the acoustical quality of a concert hall is given by a summation i ai|xi|3?2, they compared the degree of variation of the acoustical quality in 18 concert …

Reflections on the spatial-sound imagination of great composers.

Since the that W. C. Sabine (1900) defined the reverberation time as an objective quantity for the acoustic behavior of a room, acousticians have been interested in describing the quality of concert halls and opera houses through physical measurements and then finding connections between these measurements and the subjective impression of listeners and musicians. In the following decades, many additional criteria have been developed for describing the effects of direct sound, reverberation, and particularly the early reflections. It is of great merit that in the 1960s, Leo L. Beranek collected and published measurement data and comments from a multitude of concert halls which stimulated an international discussion (Beranek, 1962). Since that he has continuously updated this collection along with a special ranking system for the quality of concert halls based on the best current knowledge (Beranek, 2004).These contributions have enabled his international colleagues to compare existing and newly built halls and to draw conclusions for the design of their own projects. It is therefore not surprising that during the decades between 1960 and 2010, the fundamental concepts and particularly the shapes of the new-designed halls shifted from the hexagonal and fan-shaped halls with a rather low ceiling height of the 1960s and 1970s to more shoe-box halls or halls with surrounding audience which have been preferred from the 1980s onward (Meyer, 2011). This trend may been seen as a logical consequence of Beranek's suggestion that the initial-time-delay gap, the delay between the direct sound and the first arriving reflection, should be delayed not more than 30 ms from any direction (Beranek, 1962), in combination with later suggestions from others that the first lateral reflection should arrive before the first medial reflection from the ceiling (Barron, 1971; Marshall, 1967).Furthermore one should not ignore the fact that the preferences of listeners can vary with time. It has been found that most listeners fall into two distinct groups who disagree when judging the sensation of strength and expansion of the sound source. One group prefers a powerful sound (even if it is connected with a decrease of clarity in forte passages), and the other group always prefers high clarity- even if it is connected with lower loudness in higher dynamic ranges (Wilkens, 1975). From today's point of view, this two-part division might be explained by the possibility that the sound expectations of the first group was formed by the spatial sound impression of live concerts, and that the second group predominantly listened to records.Recent more detailed studies with a loudspeaker orchestra confirm this division of the audience into two groups based on their preferences. Using a method of sensory evaluation, the single attributes named by individual listeners have been compiled into clusters through multiple-factor analysis. The result revealed that one group of listeners liked a relatively intimate sound, in which it is quite easy to hear individual instruments and melody lines. The other group preferred a louder and more reverberant sound with good envelopment and strong bass (Lokki, Patynen, Kuusinen, & Tervo, 2012, p. 3148). Remarkably, for all listeners, subjective proximity was the attribute most highly correlated with average preference ratings.During the past decades, an additional differentiation between the two groups of listeners can be found by asking them for their motivation to attend concerts: it can be based on the program, that is, the attraction of the performed compositions, or on the desire for meeting great stars. The latter includes not only the performers, but-in the of festival tourism-attractive concert halls too. For many of these people, I believe that the architectural extravagance of the halls seems to be more important than excellent acoustics.It is an essential part of today's knowledge of the acoustical demands for good halls that the performing orchestral musicians need good conditions for mutual hearing (Dammerud, 2009), and that the conductors should be able to control the tonal1 balance of the instrumental sections as well as to get an impression of the spaciousness in the hall (Meyer, 2008). …

Combined effect of asphalt concrete cross-anisotropy and temperature variation on pavement stress–strain under dynamic loading

This study investigates the combined effects of asphalt concrete (AC) cross-anisotropy and temperature on asphalt pavement’s stress–strain under moving wheel loads. To facilitate this study, a dynamic Finite Element Model (FEM) of an instrumented pavement section on Interstate-40 (I-40) near Albuquerque, New Mexico, is developed in ABAQUS incorporating depth-temperature variations in the AC layer under a truck wheel loading. Cross-anisotropy in the model is defined as the ratio of horizontal to vertical modulus (n-value) of the AC. Field compacted AC cores were collected from the instrumented pavement section and tested in the laboratory to determine the n-value and viscoelastic parameters, which are incorporated in the FEM model using the User Defined Material (UMAT) interface in ABAQUS. Model is validated using field measured deflections and strains values under Falling Weight Deflectometer (FWD) test. The validated model is used for a parametric study by varying n-values of AC material under different pavement temperatures. It is observed that the horizontal tensile strain at bottom of the AC layer decreases as the n-value approaches 1.0 (isotropy). It indicates that the horizontal tensile strain decreases as the horizontal modulus of the AC increases. It is also observed that the vertical strains on top of pavement layers decreases with an increase in n-value. It indicates that increase in horizontal modulus of the AC leads to decrease in the vertical strains of pavement layers. The parametric study based on pavement temperature variation shows that horizontal tensile strain at bottom of the AC layer as well as vertical strains on top of AC, base, subbase, and subgrade are highly sensitive to temperature variation in AC layer.

Experimental Investigation of Soil-Atmosphere Interaction in an Instrumented Embankment Constructed with Two Treated Clays

This paper discusses the field monitoring of an experimental embankment divided into two symmetrical instrumented sections constructed with two clays treated with lime and/or cement in the northeast of France. The soil-atmosphere interaction is investigated in the monitored embankment. The field instrumentation included spatial and temporal changes of the soil suction, moisture, and temperature at predefined locations within the embankment, as well as measurements of meteorological data, collected from April to November 2011. The data show similarities in the suction daily variations trend in the two treated clays. Maximum changes in suction occur near ground surface. Even at the location of -0.75 m from the slope face the interchange of water between the atmosphere and the ground was observed in the daily soil suction measurements. No significant hydrologic response of the soils to rainfall was observed during the period of water deficit. The rainfall events showed a significant effect on the soil suction changes in the initial period of water surplus after a long period of water deficit. The comparison of the period of water deficit observed in the responses of the mean monthly suction and moisture measurements in the treated soils and the one estimated by simple water balance models based on standard meteorological observations in the region indicate that there is an overall qualitative agreement between the modelling and observational results.

The influence of childbirth experiences on women׳s postpartum traumatic stress symptoms: A comparison between Israeli Jewish and Arab women

Backgroundchildbirth is a positive experience for most women yet some women express distress after birth. Traumatic experience can sometimes cause post-traumatic stress disorder (PTSD) in relation to childbirth. Prevalence of traumatic birth experience and PTSD after childbirth differs between cultures. Objectivesto examine the subjective recall of childbirth experiences and PTSD symptoms of Israeli Jewish and Arab women; to examine comparatively the prevalence of PTSD symptoms six to eight weeks after childbirth and to establish the factors that predict PTSD symptoms. Methodsa prospective study was conducted in a region characterised by wide variations in ethnocultural groups. The study was comprised of two time points: Time 1 (T1) interviews were conducted at the bedside of the women in the maternity ward of each hospital 24–48 hours after childbirth. Time 2 (T2), all 171 women participating in T1 were interviewed by phone six to eight weeks after childbirth. Findings34 women (19.9%) reported their labour as traumatic 24–48 hours after birth (T1), and six to eight weeks later (T2) 67 women (39.2%) assessed their experience as traumatic. More Arab women (69.6%) than Jewish women (56.5%) had a positive memory of childbirth, but this difference only approached statistical significance (p=.09). Results showed rather low frequencies of PTSD symptoms, and no ethnic difference. PTSD symptoms were significantly and positively predicted by subjective recollection of childbirth experience (Time 2). PTSD symptoms were higher for women who did not have a vaginal birth, and more women with PTSD symptoms were not breast feeding. Conclusionswe found more similarities than differences between Arab and Jewish women׳s experience of their births and no differences between them on the prevalence of PTSD symptoms after birth. The results suggest that non-vaginal birth (instrumental or caesarean section) and negative recollection of the childbirth experience are important factors related to the development of PTSD symptoms after birth, and that women with PTSD symptoms are less likely to breast feed.

Moisture Variations in Unbound Layers in an Instrumented Pavement Section

Moisture Variations in Unbound Layers in an Instrumented Pavement Section

Modeling Temperature Profile of Hot-Mix Asphalt in Flexible Pavement

This study develops pavement temperature prediction models based on temperature and weather data measured from the instrumentation section on Interstate 40 (I-40) in New Mexico, USA. As a first step, pavement temperatures of asphalt concrete at different depths, air temperature and solar radiation were continuously monitored from October 15, 2012 to October 14, 2013. Using this data, statistical models were developed to predict the temperature of asphalt concrete at any depth. Comparison of additional temperature data from October 15, 2013 to January 21, 2014 validates the models. Using these models, asphalt concrete inner pavement temperature at any depth of asphalt concrete can be predicted if the surface or air temperature is known. The study outcome expects to be highly beneficial for analyzing temperature related stress-strain, validating numerical models developed to predict pavement temperature and calibrating the Pavement Mechanistic-Empirical (ME) Design Guide for pavement design.

Experimental study on circulation characteristics of secondary passive heat removal system for Chinese pressurized water reactor

Nuclear safety has attracted increasingly global attention. The secondary side natural circulation heat removal system is one of several passive safety systems designed to ensure the safety of the reactor core. The passive heat removal systems are also adopted in the safety system design of Chinese third-generation pressurized water reactor. To complete its design and verify its feasibility, an experimental facility, which is named SPHRS, was built to investigate the heat removal capacity and the stability characteristics of the steam generator secondary side passive heat removal system. The experimental facility consists of a steam generator simulator, an instrumented condenser test section with a secondary pool boiling section, a pump, a water storage tank, and associated piping and instrumentation. The heat removal capacity under varying pressures and characteristics of natural circulation at steady-state as well as system power input drop condition were obtained. The results show that the SPHRS has sufficient capacity to remove the decay heat. It is found that the natural circulation can be maintained under different pressures, the heat load sudden change condition as well, which indicates that the SPHRS natural circulation has good stability.

Field validation of recycled cold mixes viscoelastic properties

Visco-elastic properties of recycled cold mixes are analyzed in this paper by tests carried out in laboratory; the aim of the paper is to evaluate how reliable are these properties to be used for the prediction of visco-elastic response of pavement layers containing recycled cold mixes.The paper focuses on both bitumen emulsion and foam bitumen recycled cold mixes; two different mixtures were designed in laboratory to achieve specific mechanical properties and used to build two instrumented test sections. Visco-elastic properties and fatigue resistance of these mixtures were determined on cores extracted from the test sections and compared with those determined on a conventional hot asphalt mixture for base layer. This comparison allowed to highlight the reduced thermo-sensitive and time-dependant behavior of these mixtures.Visco-elastic properties of the recycled cold mixtures determined in laboratory, then were used to predict strains in the base layer of the test pavements by using the ViscoRoute 2.0 software. The comparison between measured and predicted strain pulses allowed to evaluate the reliability of visco-elastic parameters determined in laboratory to predict response of layers composed of recycled cold mixes. The obtained results show that visco-elastic parameters of bitumen emulsion recycled cold layers exhibit a satisfactorily capacity to accurately reproduce the pavement response; the same reliability cannot be found for foam bitumen recycled cold layers, whose behavior diverges significantly from that of a continuum.

Ultrasound assessment of fetal head circumference at the onset of labor as a predictor of operative delivery

Objective: This study sought to determine whether ultrasound assessment of fetal head circumference (FHC) at the onset of labor can predict the likelihood of operative delivery.Methods: We performed a prospective cohort study of 200 nulliparous women with singleton, cephalic, term pregnancies in an Irish Maternity Hospital. Transabdominal ultrasound assessment of FHC was performed when spontaneous labor was diagnosed or immediately prior to induction. Odds ratios for operative delivery (instrumental delivery or cesarean section) and maternal and neonatal morbidity were calculated using logistic regression with FHC categorized at a ≥350-mm cut-off (90th percentile).Results: Ultrasound assessment of FHC at the onset of labor was highly correlated with post-delivery neonatal head circumference (NHC) (Pearson’s correlation coefficient 0.74), suggesting that it can be measured reliably. FHC ≥350 mm was associated with more than twice the risk of any operative delivery (OR 2.5, 95% CI 1.0–6.2) and a two-fold increased risk of cesarean section for dystocia (OR 2.0, 95% CI 1.0–4.3). Differences in maternal and neonatal morbidity were not statistically significant.Conclusion: These preliminary data suggest that ultrasound assessment of FHC at the onset of labor may be useful in identifying women at greater risk of intrapartum intervention and warrant further research.

Conservation of dimer peak intensity in ion mobility spectrometers with ketone-doped carrier gas

Doping of gases in ion mobility spectrometry (IMS) is a well-known method for improvement of detection selectivity. Ionization of analyte molecules in doped carrier gas occurs as a result of reactions with so-called alternative reactant ions containing molecules of dopant. Properties of these ions are different from those of the reactant ions found in pure carrier gas. Therefore, the dopant may influence the quantitative characteristics of detection in IMS. In this work, we present the results of studying the detection of two organophosphorus compounds, dimethyl methylphosphonate (DMMP) and triethyl phosphate (TEP), conducted in the presence of ketones containing 3–9 atoms of carbon in the molecule. Experiments were carried out with a generator of gas mixtures that allowed for simultaneous introduction of two substances into the carrier gas. Our investigations indicated that for the studied analyte/dopant systems, the presence of dopant does not influence the intensity of the signal generated by dimer analyte ions. This effect was observed for IMS instruments of different construction. Dimer ions peak intensity conservation is explained based on the ion–molecule reaction kinetics and the balance of ions in the reaction sections of IMS instruments.

Field performance of retaining walls reinforced with woven and nonwoven geotextiles

ABSTRACT: This paper presents an evaluation of the performance of two instrumented sections of a geosynthetic-reinforced soil wall, 5.6 m high, constructed using a lateritic fine-grained soil. Two sections with identical layout of a nonwoven and a woven geotextile were monitored for comparison purposes. The unconfined tensile stiffness of the nonwoven geotextile was three times smaller than that of the woven geotextile. This allowed direct evaluation of the effect of soil confinement on geotextile stiffness. Instrumentation was used to measure face displacements, reinforcement displacement and strains, and soil matric suction. Rainfall occurred both during and after construction, which facilitated evaluation of the effect of soil wetting on the walls performance. Ultimate and serviceability limit state analyses were conducted to gain further insight into the performance of the two walls. The results show that the performance of the section reinforced with nonwoven geotextile was equivalent to the one reinforced with woven geotextile, even after the observed reduction in matric suction after rainfall. For both sections, the overall deformations occurred during construction. Negligible deformations were observed during service. Maximum face displacements were measured in the lowest instrumented layer for the nonwoven geotextile section whereas it was in the highest layer for the woven geotextile section. These behaviours of face displacement distributions can be the result of the significant differences in global stiffness of the sections. Design analyses and field performance show that soil confinement has a beneficial effect on the nonwoven geotextile stiffness. The significant contribution of the soil cohesion of the lateritic soil played an important role in the behaviour of the nonwoven geotextile-reinforced wall.

2014 Atomic Spectrometry Update – a review of advances in X-ray fluorescence spectrometry

This review describes advances in the continued expansion of work using the XRF group of techniques published approximately between April 2013 and March 2014. Specialised laboratory instrumentation, X-ray sources, detector development and data processing continue unabated. It is remarkable how quickly hand-held XRF instrumentation has developed to the point where many examples of its use are included in the various application sections of this review, rather than in the instrumentation section. Several new beam lines and their new end-stations were described in publications from SR research centres around the world. More analysts are attracted to TXRF and related techniques with new sample preparation techniques offered for an expanding range of applications. Nanoparticles and nanomaterials feature throughout this review particularly in clinical, biological and environmental studies. A novel approach for the reuse of industrial by-products described how acid mine drainage sludge and coal fly ash facilitated the problem of the high levels of phosphate present in waste waters (cow dung) from the dairy industry. The archaeological and cultural heritage section often includes good news stories. This year we learn how an XRF mapping technique was used to show that Pablo Picasso used a popular brand of French house paint in his works of art.

A Study on Cross-anisotropy of Unbound Layers of Pavement Considering Nonlinearity

The effects of cross-anisotropy of unbound layer materials on the stress-strain response of a pavement under Falling Weight Deflectometer (FWD) test load are determined at three temperatures employing a dynamic Finite Element Model (FEM) in ABAQUS. Viscoelastic behavior of Asphalt Concrete (AC) is characterized by laboratory dynamic modulus test. Nonlinear elasticity of base material is incorporated through a User Defined Material (UMAT) subroutine. Cross-anisotropy is introduced by changing the ratio of horizontal to vertical stiffness (n-value) of unbound layers. FEM model is validated using field collected stress-strain under FWD test on the instrumented pavement section at mile post 141 (MP 141) on Interstate 40 (I-40) near Albuquerque, New Mexico. It is observed that tensile strain at the bottom of the AC layer is influenced by the base layer cross-anisotropy whereas vertical strain in this layer is barely affected by the cross-anisotropy of the unbound layers. However, vertical strains in the unbound layers are significantly affected by cross-anisotropy. Therefore, it can be postulated that fatigue damage by tensile strain at the bottom of AC layer, and rutting by vertical strain should be evaluated for unbound layer cross-anisotropy in the pavement design. Overall, strain responses due to cross-anisotropy are highly sensitive to temperature.