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BACKGROUND The process of online teaching and learning had an impact on both teachers and students;as a result, for the students who were assigned (confined) to staying home there were limited opportunities to practice in the clinic The aim of this study was to assess foreign medical student's perception about the efficiency of the remote teaching method, and to investigate their opinion about implementing some online teaching features even after the pandemic period would pass METHODS A questionnaire was created, providing questions related to social-demographic factors and 20 statements for assessing the opinion of the respondents regarding the online educational process implemented during the pandemic period The questionnaires were distributed by email RESULTS 459 answers were statistically analyzed We noticed that students accepted remote lectures and other learning activities due to the higher risk of contamination But among those who wrote an answer to this question, many would like to restart the classic activities as soon as possible, especially for the labs or clinical practice We observed also a tendency to accept remote lectures, or a combination between online and traditional lectures, after the pandemic period is over CONCLUSIONS Considering the results of the present survey, we can affirm that foreign students had an overall positive opinion about the acceptability and usability of online medical learning Students viewed online activities as helpful, but as a supplement to their learning rather than a replacement for traditional teaching methods

3D printing of amorphous and crystalline ceramics is of paramount importance for the fabrication of a wide range of devices with applications across different technology fields. Printed ceramics are remarkably enabled by the sol–gel synthesis method in conjunction with continuous filament direct ink writing. During printing, multiple processes contribute to the evolution of inks including shape retention, chemical conversion, solidification, and microstructure formation. Traditionally, depending on the ink composition and printing environment, several mechanisms have been associated with the shape retention and solidification of 3D printed structures: gelation, rapid solvent evaporation, energy-driven phase transformation, and chemical-driven phase transformation. Understanding the fundamental differences between these mechanisms becomes key since they strongly influence the spatiotemporal evolution of the materials, as the out-of-equilibrium processes inherent to the extrusion, relaxation, and solidification of printed materials have significant effects on the materials properties. In this work, we investigate the shape retention mechanism and the hydrolysis-induced material conversion and microstructure formation during the 3D printing of a water reactive sol–gel ink that transforms into titanium dioxide-based ceramic. This study aims at identifying characteristic mechanisms associated with the material transformation, establishing connections between the microstructure development and the timescales associated with solidification under operando 3D-printing conditions. The investigation of this material’s out-of-equilibrium pathways under processing conditions is enabled by time-resolved coherent X-ray scattering, providing simultaneous access to temporospatially resolved microstructural and dynamics information. Furthermore, we explore X-ray speckle tracking as a tool to resolve deformations of the microstructure in a printed filament associated with the deposition of consecutive filaments. Through this work, we aim at providing a fundamental understanding of the relationships behind these transformative processes in 3D printing and their timescales as the basis for achieving unprecedented control over printed materials microstructure.

Detailed simulations of experiments carried out at modern light sources are directly related to the most efficient and productive use of these facilities for research in multiple branches of science and technology. The “Synchrotron Radiation Workshop” computer code with its Python interface, and Sirepo web-browser-based graphical user interface, currently supports physical optics simulations of coherent X-ray scattering and imaging experiments on user-defined virtual samples. We present examples of simulations of coherent scattering experiments that are typically performed at the Coherent Hard X-ray beamline at Brookhaven National Laboratory’s (BNL) National Synchrotron Light Source II. We also present several comparisons of the simulations with the results of actual coherent X-ray scattering experiments with nano-fabricated test samples produced at BNL’s Center for Functional Nanomaterials.

X-ray Compound Refractive Lenses (CRLs) made out of diamond have a number of attractive features for applications at modern light sources, such as relatively large refractive index decrement and yet relatively low absorption for hard Xrays, low thermal expansion coefficient and high mechanical rigidity (allowing to safely use them as first optical elements of beamlines), and relatively low undesirable scattering from their volume. However, diamond CRLs are hard to fabricate and process to a (sub-)micron accuracy of the surface shape, required for aberration-free focusing of hard Xrays. We will report on results of experimental tests of first generation 2D diamond CRLs manufactured by Euclid Techlabs LLC. The tests were performed at the Coherent Hard X-ray beamline of the National Synchrotron Light Source II, and included measurements of intensity profiles of ~13 keV undulator radiation focused by one diamond lens in a low-demagnification geometry. Such geometry is typically used for the X-ray beam transport and can be used for the imaging-based diagnostics of the emitting electron beam. The quality of X-ray focusing with the new diamond CRL was analyzed by comparing the measurement results with partially-coherent wave-optics simulations performed with Synchrotron Radiation Workshop code. The tests of the diamond CRL also included measurements of small-angle X-ray scattering produced by it, and comparison of these data with the scattering data from a beryllium CRL with the same focal length.

In this paper, we summarize briefly some of the future trends in synchrotron science as seen at the National Synchrotron Light Source II, a new, low emittance source recently commissioned at Brookhaven National Laboratory. We touch upon imaging techniques, the study of dynamics, the increasing use of multimodal approaches, the vital importance of data science, and other enabling technologies. Each are presently undergoing a time of rapid change, driving the field of synchrotron science forward at an ever increasing pace. It is truly an exciting time and one in which Roger Cowley, to whom this journal issue is dedicated, would surely be both invigorated by, and at the heart of.

OBJECTIVE To determine whether PostureScreen® Mobile app is a useful, simple tool that is accessible for dentists to evaluate the correlation between malocclusion and posture. METHODS Twenty-nine subjects underwent static and dynamic dental occlusion examinations and a postural exam with PostureScreen® Mobile app, a photographic method. The subjects were divided into groups depending on their static and dynamic occlusion features. The postural parameters were then compared between these groups. RESULTS Statistically significant differences (p

In-vacuum undulators (IVU) [1–7] are used extensively at light source facilities, in particular at medium-energy storage rings, where these devices are the main sources of high-brightness hard X-ra...

A new technique is presented to allow the measurement of weakly scattering samples despite a high-background environment. Coherent interference between the sample and a nanofabricated ‘amplifier’ structure generates a strong interference scattering pattern, which can be analyzed using angular correlation functions to reconstruct the sample’s symmetry., Small-angle X-ray scattering (SAXS) often includes an unwanted background, which increases the required measurement time to resolve the sample structure. This is undesirable in all experiments, and may make measurement of dynamic or radiation-sensitive samples impossible. Here, we demonstrate a new technique, applicable when the scattering signal is background-dominated, which reduces the requisite exposure time. Our method consists of exploiting coherent interference between a sample with a designed strongly scattering ‘amplifier’. A modified angular correlation function is used to extract the symmetry of the interference term; that is, the scattering arising from the interference between the amplifier and the sample. This enables reconstruction of the sample’s symmetry, despite the sample scattering itself being well below the intensity of background scattering. Thus, coherent amplification is used to generate a strong scattering term (well above background), from which sample scattering is inferred. We validate this method using lithographically defined test samples.

Background: All body systems involved in ensuring a healthy posture (musculoskeletal system, oculomotor, oto-vestibular and occluso-cranial-mandibular) are essential in maintaining postural balance. Research Question: Does experimental malocclusion in subjects in static position determine variations in plantar pressure? Methods: Overall, 31 subjects were included in the study. The plantar pressure was evaluated in five different points: lateral and medial heel, midfoot, 1st and 5th metatarsal area. Using a specially designed splint, an artificial malocclusion was induced on the right hemimandibular arch. The pressure was measured at 0 (T0), 15 (T1) and 30 min (T2) after splint application. Results: The right external plantar sensors recorded statistically significant differences in pressure values after 15 min of splint wear (5th metatarsal area, p = 0.05; midfoot, p = 0.04). Important pressure values were also recorded by the left internal plantar sensors (1st metatarsal, p = 0.01; medial heel, p = 0.006), after 30 min of splint wear. Conclusions: Asymmetrical experimental malocclusion produces early changes in plantar pressure, a proof of compensatory mechanisms induced by secondary postural imbalance.

Additive printing techniques are regarded as revolutionary and versatile methods of advanced device manufacturing, stemming from the possibility to pattern materials on a custom-based approach and the potential to create novel microstructures and achieve new functionalities. Despite these advantages, the inherent anisotropy of the printing process is a source of property gradients within the printed materials, often associated with variable and/or poor performance. Up to date, the evolutionary pathways associated with printing have largely remained unaddressed, mainly owing to the difficulty to study the transformations induced in the material during processing. Time-resolved coherent X-ray scattering techniques, such as X-ray photon correlation spectroscopy, enable the in situ study of transient nanoscale and mesoscale states in a large variety of materials, including amorphous ones, by directly accessing the most relevant timescales and length scales of their nanoscale and mesoscale dynamics, self-assembly, and mesostructure evolution. We conduct in operando studies of continuous-flow direct writing with colloidal inks, focusing on how the ink formulation and ink-substrate interactions affect the processes that determine the macroscopic properties of the printed materials. We find fundamental differences in the ink structural relaxations emerging from the primary colloid properties (monodisperse versus aggregated colloids) and the substrates surface energy and mechanical properties. Our work helps to reveal and quantify the basic science governing the evolution of 3D-printed materials during processing, ultimately improving engineering criteria for the design of printable materials.

High-accuracy physical optics calculation methods used in the “Synchrotron Radiation Workshop” (SRW) allow for multiple applications of this code in different areas, covering development, commissioning, diagnostics and operation of X-ray instruments at light source facilities. This presentation focuses on the application of the SRW code for the simulation of experiments at these facilities. The most complete and most detailed simulation of experiments with SRW is possible in the area of elastic coherent scattering, where the interaction of radiation with samples can be described with the same transmission-type “propagators” that are used for the simulation of fully- and partially-coherent radiation propagation through X-ray optical elements of beamlines. A complete “source-to-detector” simulation of such an experiment for a lithographic sample is described here together with comparisons of the simulated coherent scattering data with actual measurements results, obtained at the Coherent Hard X-ray (CHX) beamline of the National Synchrotron Light Source II (NSLS-II). Particular attention is paid to the analysis of visibility of speckles and intensity levels in the scattered radiation patterns at different degrees of coherence of the radiation entering the sample.

We present the application of fully- and partially-coherent synchrotron radiation wavefront propagation simulation functions, implemented in the "Synchrotron Radiation Workshop" computer code, to create a ‘virtual beamline’ mimicking the Coherent Hard X-ray scattering beamline at NSLS-II. The beamline simulation includes all optical beamline components, such as the insertion device, mirror with metrology data, slits, double crystal monochromator and refractive focusing elements (compound refractive lenses and kinoform lenses). A feature of this beamline is the exploitation of X-ray beam coherence, boosted by the low-emittance NSLS-II storage-ring, for techniques such as X-ray Photon Correlation Spectroscopy or Coherent Diffraction Imaging. The key performance parameters are the degree of Xray beam coherence and photon flux, and the trade-off between them needs to guide the beamline settings for specific experimental requirements. Simulations of key performance parameters are compared to measurements obtained during beamline commissioning, and include the spectral flux of the undulator source, the degree of transverse coherence as well as focal spot sizes.

The paper presents an overview of the main functions and new application examples of the “Synchrotron Radiation Workshop” (SRW) code. SRW supports high-accuracy calculations of different types of synchrotron radiation, and simulations of propagation of fully-coherent radiation wavefronts, partially-coherent radiation from a finite-emittance electron beam of a storage ring source, and time-/frequency-dependent radiation pulses of a free-electron laser, through X-ray optical elements of a beamline. An extended library of physical-optics “propagators” for different types of reflective, refractive and diffractive X-ray optics with its typical imperfections, implemented in SRW, enable simulation of practically any X-ray beamline in a modern light source facility. The high accuracy of calculation methods used in SRW allows for multiple applications of this code, not only in the area of development of instruments and beamlines for new light source facilities, but also in areas such as electron beam diagnostics, commissioning and performance benchmarking of insertion devices and individual X-ray optical elements of beamlines. Applications of SRW in these areas, facilitating development and advanced commissioning of beamlines at the National Synchrotron Light Source II (NSLS-II), are described.

A set of new data analysis software tools have been developed for the study of structural dynamics of materials using coherent scattering and photon correlation techniques. The new software tools can readily process high-throughput, multidimensional data, enabling studies of slow and fast dynamics of materials using X-ray Speckle Visibility Spectroscopy and X-ray Photon Correlation Spectroscopy techniques. They support a wide range of user expertise, from novice to developer, and are available in Scikit-beam python package which is available at https://github.com/scikit-beam/scikit-beam.

11 pags., 6 figs., 1 tab., X Ray Photon Correlation Spectroscopy, XPCS, is a novel technique developed for the study of slow dynamics in condensed matter. The principle of this technique is based on the time variations of the speckle pattern originated by the scattering of coherent light from a material with spatial inhomogeneities. Although laser photon correlation spectroscopy was long established, XPCS has only been possible with the advent of new synchrotron radiation X-ray sources that can provide sufficient coherent flux. The results from these techniques and future perspectives in the field of polymer science are discussed here. © 2016 Elsevier Ltd. All rights reserved., The authors gratefully acknowledge financial support from the MINECO, Spain (MAT2014-59187-R) and from NSLS-II under contract No. DE-SC0012704 with the US Department of Energy.

Commissioning of the first X-ray beamlines of NSLS-II included detailed measurements of spectral and spatial distributions of the radiation at different locations of the beamlines, from front-ends to sample positions. Comparison of some of these measurement results with high-accuracy calculations of synchrotron (undulator) emission and wavefront propagation through X-ray transport optics, performed using SRW code, is presented.

We have applied fully-and partially-coherent synchrotron radiation wavefront propagation simulations, implemented in the “Synchrotron Radiation Workshop” (SRW) computer code, to analyse the effects of imperfect mirrors and monochromator at the Coherent Hard X-ray beamline. This beamline is designed for X-ray Photon Correlation Spectroscopy, a technique that heavily relies on the partial coherence of the X-ray beam and benefits from a careful preservation of the X-ray wavefront. We present simulations and a comparison with the measured beam profile at the sample position, which show the impact of imperfect optics on the wavefront.

Preliminary X-ray correlation spectroscopy results from the novel three-dimensional vertically integrated photon imaging chip (VIPIC) detector are presented., The Vertically Integrated Photon Imaging Chip (VIPIC) was custom-designed for X-ray photon correlation spectroscopy, an application in which occupancy per pixel is low but high time resolution is needed. VIPIC operates in a sparsified streaming mode in which each detected photon is immediately read out as a time- and position-stamped event. This event stream can be fed directly to an autocorrelation engine or accumulated to form a conventional image. The detector only delivers non-zero data (sparsified readout), greatly reducing the communications overhead typical of conventional frame-oriented detectors such as charge-coupled devices or conventional hybrid pixel detectors. This feature allows continuous acquisition of data with timescales from microseconds to hours. In this work VIPIC has been used to measure X-ray photon correlation spectroscopy data on polystyrene latex nano-colliodal suspensions in glycerol and on colloidal suspensions of silica spheres in water. Relaxation times of the nano-colloids have been measured for different temperatures. These results demonstrate that VIPIC can operate continuously in the microsecond time frame, while at the same time probing longer timescales.

Coherent X-ray scattering is an emerging technique for measuring structure at the nanoscale. Data management and analysis is becoming a bottleneck in this technique. We present an unsupervised method which can sort and cluster the scattering snapshots, uncovering patterns inherent in the data. Our algorithm operates without resorting to templates, specific noise models, or user-directed learning. We test our methods using scattering images of two-dimensional nanoparticle assemblies. The experimental results show the effectiveness of our algorithm on real world scientific data.

A new approach is proposed for measuring structural dynamics in materials from multi-speckle scattering patterns obtained with partially coherent X-rays. Coherent X-ray scattering is already widely used at high-brightness synchrotron lightsources to measure dynamics using X-ray photon correlation spectroscopy, but in many situations this experimental approach based on recording long series of images (i.e.movies) is either not adequate or not practical. Following the development of visible-light speckle visibility spectroscopy, the dynamic information is obtained instead by analyzing the photon statistics and calculating the speckle contrast in single scattering patterns. This quantity, also referred to as the speckle visibility, is determined by the properties of the partially coherent beam and other experimental parameters, as well as the internal motions in the sample (dynamics). As a case study, Brownian dynamics in a low-density colloidal suspension is measured and an excellent agreement is found between correlation functions measured by X-ray photon correlation spectroscopy and the decay in speckle visibility with integration time obtained from the analysis presented here.

In this work we have demonstrated a 256-channel(element) correlator array design based on a Virtex 6 FPGA for X-ray Photon Correlation Spectroscopy that uses Dynamic Light Scattering to probe nanometer scale structures, where the channel here means one correlator element which could provide auto correlation functions for 36 lags. This design is incorporated along with a design consisting of a 64×64 pixel silicon detector array and a custom 3D integrated circuit called vertically integrated pixel imaging chip (VIPIC). The challenge was how to handle the large amounts of data from VIPIC while performing correlation analysis in a real time. Our design introduces an autocorrelator per pixel to address the per pixel momentum transfer. Initially the VIPIC collects the X-ray photon arrival events from the 64×64 pixels and transfers it over 16 serial buses to the data acquisition system. Timing information is provided by reading the detector contents every 10µs. Readout can be in one of two modes, a sparsified readout mode for low intensity applications where many pixels acquire no events, and an imaging mode in which all pixels are read out sequentially. The correlator design described here can handle either operating mode. This design provides many advantages over the existing commercial correlators as they are not able to meet the requirements of VIPIC. The commercial ones are limited to low intensity light correlation and a few simultaneous inputs. Besides, the large physical size of the commercial correlators makes the implementation of a system with several channels impractical. A multi-τ correlator design based on virtex 2 was addressed earlier but the practical realization was only ended up for one element of such muti-τ correlator. The correlator design discussed in this paper will provide a correlation dynamic range from 10us to 10.24ms for each of its 256 correlator elements. Our target for the design is to reach the minimum physical size, resource and power consumption costs based on the approach of using an 8 stage multi-τ design for each element and barrel shift DSPs and pipelined RAM block for the elements. We are planning to implement this design as the basis for a custom integrated circuit which implements 4×256 element correlator elements.

Ultra-low emittance third-generation synchrotron radiation sources such as the NSLS-II offer excellent opportunities for the development of experimental techniques exploiting x-ray coherence. Coherent light scattered by a heterogeneous sample produces a speckle pattern characteristic for the specific arrangement of the scatterers. This may vary over time, and the resultant intensity fluctuations can be measured and analyzed to provide information about the sample dynamics. X-ray photon correlation spectroscopy (XPCS) extends the capability of dynamic light scattering to opaque and turbid samples and extends the measurements of time evolution to nanometer length scales. As a consequence XPCS became crucial in the study of dynamics in systems including, but not being limited to, colloids, polymers, complex fluids, surfaces and interfaces, phase ordering alloys, etc. In this paper we present the conceptual optical design and the theoretical performance of the Coherent Hard X-ray (CHX) beamline at NSLS-II, dedicated to XPCS and other coherent scattering techniques. For the optical design of this beamline, there is a tradeoff between the coherence needed to distinguish individual speckles and the phase acceptance (high intensity) required to measure fast dynamics with an adequate signal-to-noise level. As XPCS is a "photon hungry" technique, the beamline optimization requires maximizing the signal-to-noise ratio of the measured intensity-intensity autocorrelation function. The degree of coherence, as measured by a two-slit (Young) experiment, is used to characterize the speckle pattern visibilities. The beamline optimization strategy consists of maximization of the on-sample intensity while keeping the degree of coherence within the 0.1-0.5 range. The resulted design deviates substantially from an ad-hoc modification of a hard x-ray beamline for XPCS measurements. The CHX beamline will permit studies of complex systems and measurements of bulk dynamics down to the microsecond time scales. In general, the 10-fold increase in brightness of the NSLS-II, compared to other sources, will allow for measurements of dynamics on time-scales that are two orders of magnitude faster than what is currently possible. We also conclude that the common approximations used in evaluating the transverse coherence length would not be sufficiently accurate for the calculation of the coherent properties of an undulator-based beamline, and a thorough beamline optimization at a low-emittance source such as the NSLS-II requires a realistic wave-front propagation analysis.

Partially-coherent wavefront propagation calculations have proven to be feasible and very beneficial in the design of beamlines for 3rd and 4th generation Synchrotron Radiation (SR) sources. These types of calculations use the framework of classical electrodynamics for the description, on the same accuracy level, of the emission by relativistic electrons moving in magnetic fields of accelerators, and the propagation of the emitted radiation wavefronts through beamline optical elements. This enables accurate prediction of performance characteristics for beamlines exploiting high SR brightness and/or high spectral flux. Detailed analysis of radiation degree of coherence, offered by the partially-coherent wavefront propagation method, is of paramount importance for modern storage-ring based SR sources, which, thanks to extremely small sub-nanometer-level electron beam emittances, produce substantial portions of coherent flux in X-ray spectral range. We describe the general approach to partially-coherent SR wavefront propagation simulations and present examples of such simulations performed using "Synchrotron Radiation Workshop" (SRW) code for the parameters of hard X-ray undulator based beamlines at the National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory. These examples illustrate general characteristics of partially-coherent undulator radiation beams in low-emittance SR sources, and demonstrate advantages of applying high-accuracy physical-optics simulations to the optimization and performance prediction of X-ray optical beamlines in these new sources.

International audience; The paper presents the results of an experimental campaign of the GNSS transmitter-based approach for indoor positioning. Details on the chosen setup are given and the main features of the system are described in full. Comments on the positioning accuracies obtained, together with the description of the real environment are provided and an analysis of the performance of the system is proposed. For the next few years the continuity of the positioning service indoors will continue to be a real challenge. GNSS, sensor networks or WLAN approaches have been proposed in order to provide this continuity [1-4]. The GNSS-based approaches aim at making a better exploitation of the satellite signal on the receiver side. Unfortunately, techniques like HS-GPS or A-GPS [5-6] do not seem to provide a definitive solution. Local infrastructure-based solutions can help establish a final system with good accuracy and a wide coverage: the approach described in the paper uses GPS transmitters that make GPS signals available indoors

International audience; Gaussian beam launching is proposed as an alternative to ray-based techniques for propagation channel modeling, and it is implemented and validated in the context of indoor propagation. A rigorous Gabor frame decomposition of source fields is used to represent a radiated field as a superposition of shifted and rotated Gaussian beams, conveniently expressed as complex rays. Beam tracking through multiple reflections and transmissions is straightforward, and fields can then be evaluated by summation of closed form expressions. The parameters of a given transformed Gaussian beam have to be calculated only once for all observation points, leading to easy implementation, and computationally efficient algorithms. Simulations of amplitude-delay profiles, mean excess delay, and RMS delay spread are performed in an indoor environment at 60 GHz and compared to measured and published results

We present a Coherent X-ray Diffraction study of the antiferrodistortive displacive transition of SrTiO$_3$, a prototypical example of a phase transition for which the critical fluctuations exhibit two length scales and two time scales. From the microbeam x-ray coherent diffraction patterns, we show that the broad (short-length scale) and the narrow (long-length scale) components can be spatially disentangled, due to 100 $\mu$m-scale spatial variations of the latter. Moreover, both components exhibit a speckle pattern, which is static on a $\sim$10 mn time-scale. This gives evidence that the narrow component corresponds to static ordered domains. We interpret the speckles in the broad component as due to a very slow dynamical process, corresponding to the well-known \emph{central} peak seen in inelastic neutron scattering., Comment: 4 pages, 3 figures, accepted in PRL

An unexpected dichotomic long time aging behaviour is observed in a glassy colloidal clay suspension investigated by X-ray photon correlation spectroscopy and dynamic light scattering. In the long time aging regime the intensity autocorrelations are non-exponential, following the Kohlrausch–Williams–Watts functional form with an exponent bQ. We show that for spontaneously aged samples a stretched behaviour (bQ < 1) is always found. Surprisingly a compressed exponent (bQ > 1) appears only when the system is rejuvenated by application of a shear field. In both cases the relaxation times scale as Q 1. These observations shed light on the origin of compressed exponential behaviour and help in classifying previous results in the literature on anomalous dynamics.

Millimeter waves offer attractive possibilities for wireless indoor communication systems. Among the advantages over microwaves are the increased bandwidth and the low probability of interference. Few results are, however, available for the channel modelisation. A new technique for the amplitude-delay profile evaluation at such frequencies, using Gaussian beam tracking, is proposed here. This technique is based on Gabor frame theory which leads to the decomposition of source fields into a set of Gaussian windows. The field radiated by each window is put in the form of a Gaussian beam, and tracked in the environment. The total received field is obtained by superposition, taking into account the coupling factor to a given receiving antenna pattern. The amplitude-delay profile is obtained directly from propagation delay computation.

With third generation synchrotron X‐ray sources, it is possible to acquire detailed structural information about the system under study with time resolution orders of magnitude faster than was possible a few years ago. These advances have generated many new challenges for changing and controlling the state of the system on very short time scales, in a uniform and controlled manner. For our particular X‐ray experiments [1] on crystallization or order‐disorder phase transitions in metallic alloys, we need to change the sample temperature by hundreds of degrees as fast as possible while avoiding over or under shooting. To achieve this, we designed and implemented a computer‐controlled temperature tracking system which combines standard Proportional‐Integral‐Derivative (PID) feedback, thermal modeling and finite difference thermal calculations (feedforward), and Kalman filtering of the temperature readings in order to reduce the noise. The resulting Kalman‐Predictive‐Proportional‐Integral‐Derivative (KPPID) algorithm allows us to obtain accurate control, to minimize the response time and to avoid over/under shooting, even in systems with inherently noisy temperature readings and time delays. The KPPID temperature controller was successfully implemented at the Advanced Photon Source at Argonne National Laboratories and was used to perform coherent and time‐resolved X‐ray diffraction experiments.

A shooting and bouncing beams (SBB) method is presented, for indoor propagation channel modeling. The advantage of the method comes from the fact that the number of beams to be launched is smaller than the number of rays in ray-tracing or ray-launching methods. The SBB method is particularly well suited for the millimeter wave range. Its application is illustrated by radio coverage simulations in a corridor at 37.2 GHz. Simulated results are compared with experimental results.

A simple Boron fiber based interference scheme [1] and other similar schemes are currently routinely used for X-ray coherence estimation at 3rd generation synchrotron radiation sources. If such a scheme is applied after a perfect monochromator and without any focusing / transport optics in the optical path, the interpretation of the measured interference pattern is relatively straightforward and can be done in terms of the basic parameters of the source [2]. However, if the interference scheme is used after some focusing optics, e.g. close to the X-ray beam waist, the visibility of fringes can be significantly affected by the new shape of the focused beam phase-space. At the same time, optical element imperfections still have a negative impact on the transverse coherence. In such situations, which are frequently encountered in experiments at beamlines, the quantitative interpretation of a measured interference pattern is not straightforward. Here we show that this can nevertheless be done by using partially-coherent synchrotron radiation wavefront propagation simulations. The results obtained from measurements, performed at the 32-ID undulator beamline of the Advanced Photon Source, and wavefront propagation based simulations show, in particular, that new generation 1D Beryllium Compound Refractive Lenses [3, 4] do not reduce the X-ray transverse coherence in any significant manner.

An overview of the basic principles, the approach to fully- and partially-coherent synchrotron radiation wavefront propagation simulations, implemented in the "Synchrotron Radiation Workshop" (SRW) computer code, and simulation examples for different types of sources, including undulator and wiggler, different beamlines and experiments, are presented. Recent developments, such as the support of parallel calculations, which considerably increase the efficiency of partially-coherent wavefront propagation calculations, are described.