Measurement Protocol Research Articles

In situ synchrotron X-ray total scattering measurements and analysis of colloidal CsPbX3 nanocrystals during flow synthesis.

In situ X-ray scattering measurements of CsPbX3 (X = Cl, Br, I) nanocrystal formation and halide exchange at NSLS-II beamlines were performed in an automated flow reactor. Total scattering measurements were performed at the 28-ID-2 (XPD) beamline and small-angle X-ray scattering at the 16-ID (LiX) beamline. Nanocrystal structural parameters of interest, including size, size distribution and atomic structure, were extracted from modeling the total scattering data. The results highlight the potential of these beamlines and the measurement protocols described in this study for studying dynamic processes of colloidal nanocrystal synthesis in solution with timescales on the order ofseconds.

Measuring glass transition of a polymer coating layer over working fiber using forward Brillouin scattering.

The glass transition temperature is a key parameter of polymer coating layers that protect optical fibers, and it affects the proper function of the fibers in their service environment. Established protocols for glass transition temperature measurements are destructive, require samples of specific geometries, and may only be carried out offline. In this work, we report the nondestructive measurement of the glass transition temperature of an acrylate polymer coating layer over a working standard fiber. The method is based on forward stimulated Brillouin scattering. A large decrease in the modulus of the coating layer above the glass transition temperature manifests in the narrowing of the modal linewidths in the forward Brillouin scattering spectrum. The transition temperature agrees with the standard dynamic mechanical analysis of samples made of the same polymer. The protocol can be useful for coating materials research and development, production line quality assurance, and preventive maintenance.

Thermal decomposition of 1-ethyl-3-methylimidazolium acetate

To realize the potential applications of ionic liquids as working fluids and solvents one should have knowledge about their long-term stability, which depends on their thermally initiated decomposition. However, the possible decomposition pathways are not yet known accurately. 1-Ethyl-3-methylimidazolium acetate ([C2Mim][OAc]) is widely studied and shows potential in cellulose dissolution. In this study, we investigate possible [C2Mim][OAc] decomposition pathways by combining decomposition experiments and ab initio rate constant computations. Both approaches yield activation energies around 135 kJ·mol−1, which significantly deviate from earlier TGA measurements with open surface yielding 100–110 kJ·mol−1 and are probably affected by evaporation. Our study uses an improved TGA measurement protocol with a sealed pan with a tiny hole that fosters measurement of the actual chemical process leading to mass loss. Ab initio computations of this study comprise vapor-liquid equilibria of reactants and products as well as forward and reverse reaction rate constants in the gas and liquid phase. Calculations for the gas phase closely match a first-order analysis of the experiments, but calculations for the liquid phase strongly depend on the quality of solvation modeling. The computations indicate that the SN2 pathway with an activation energy of 142–144 kJ·mol−1 dominates thermal decomposition of [C2Mim][OAc].

Value of Diaphragm Ultrasonography for Extubation: A Single-Blinded Randomized Clinical Trial.

Daily evaluation of mechanically ventilated (MV) patients is essential for successful extubation. Proper withdrawal prevents complications and reduces the cost of hospitalization in the intensive care unit (ICU). Diaphragm ultrasonography (DUS) has emerged as a potential instrument for determining whether a patient is ready to be extubated. This study compared the efficacy rate of extubation using a standard withdrawal protocol and DUS in patients with MV. A randomized, parallel, single-blind, controlled study was conducted on ICU patients undergoing MV. Patients were randomly assigned to either the control (conventional weaning protocol) group or intervention (DUS-guided weaning) group in a 1 : 1 ratio. The primary outcome measure was the rate of reintubation and hospital mortality. Forty patients were randomized to the trial. The mean age of the sample was 70 years, representing an older population. The extubation success rate was 90% in both groups. There was no reintubation in the first 48 hours and only two reintubations in both groups between the second and seventh days. The hospital mortality risk in patients with acute kidney injury was positively correlated with age and the need for hemodialysis. Discussion. This study demonstrates the usefulness of DUS measurement protocols for withdrawing MV. The rate of reintubation was low for both cessation methods. As a parameter, the diaphragm thickness fraction comprehensively evaluates the diaphragm function. The results demonstrate that DUS has the potential to serve as a noninvasive tool for guiding extubation decisions. In conclusion, using DUS in patients with respiratory failure revealed no difference in reintubation rates or mortality compared with the conventional method. Future research should concentrate on larger, multicentered, randomized trials employing a multimodal strategy that combines diaphragmatic parameters with traditional clinical withdrawal indices.

Electron paramagnetic resonance spectroscopy for the detection of radiation exposure in dreissenid mussels.

Electron paramagnetic resonance (EPR) spectroscopy, established for radiation measurements in calcified tissues, was identified as a methodology that merits investigation for the purpose of environmental radiation measurements using dreissenid mussels from the Great Lakes. With the refinement of sample preparation and measurement protocols, a linear relationship of dose with the peak-to-peak height of the radiation-induced signal at g = 2.0034 was established. A dedicated analysis algorithm was developed to process batches of samples, eliminating the need for manual peak-to-peak height measurement. Varying background EPR signals were identified in different sampling groups, with samples gathered in winter having a markedly lower background signal. Through optimisation of spectrum acquisition normalisation methods, it was possible to resolve doses as low as 0.2 Gy. This work provides further validation that EPR dosimetry of shelled species has the potential to contribute to better characterisation of absorbed doses in aquatic environments.

Non-invasive investigations of closed landfills: An example in a karstic area

The monitoring of existing landfills is a pending environmental issue for the years to come. This monitoring is particularly challenging in the more and more common case of closed landfills, where direct investigation is difficult or impossible, calling for non-invasive methods, which in turn are stretched to maximizing their imaging capabilities in front of difficult logistical constraints, requiring novel and well-conceived scientific approaches. In this study we present a non-invasive approach designed and calibrated to identify the state of the subsoil underlying a closed urban waste landfill. In the presented case, two main questions had to be addressed: (a) whether large karstic cavities are present under the landfill, and (b) if any leachate leakage is present. A 3D Electrical Resistivity Tomography (ERT) configuration was used to solve the problem. The survey design has made use of forward model simulations, in order to verify whether the proposed approach was capable of imaging the possible large karstic cavities. This preliminary study showed the importance of choosing a suitable measurement protocol to recover the true position of the cavities. The analysis of the real field data did not show any anomaly compatible with the presence of large cavities, and thus, in comparison with the previous simulations, led to the conclusion that such cavities are not present. However, the results showed the presence of an electrically conductive anomaly, potentially be linked to leachate release. Direct investigations (drilling and sampling) confirmed the presence of fresh water in a silty sediment environment, both contributing towards the observed larger electrical conductivity, larger than the surrounding drier limestone bedrock. The presented general approach proved to be a valuable, generalizable, tool towards for the characterization and monitoring of closed landfills.

Development and Application of Health Measurement Tools and Protocols for Forest Therapy Program through Pilot Test and Qualitative Analysis

Development and Application of Health Measurement Tools and Protocols for Forest Therapy Program through Pilot Test and Qualitative Analysis

Advances in benchmarking and round robin testing for PEM water electrolysis: Reference protocol and hardware

While the number of publications in the PEM water electrolysis community increases each year, no common ground concerning reference hardware (test cells and test bench) and testing protocols has been yet established. This would, however, be necessary for the comparability of experimental results. First attempts for such reference hardware and procedures have been made in the framework of the Task 30 Electrolysis within the Technology Collaboration Programme on Advanced Fuel Cells (AFC TCP) of the International Energy Agency (IEA). Since then, improvements of both the test hardware (test cell and components) as well as the measurement protocol were identified, and a revised methodology and key results based on a comprehensive measurement series have been obtained. A detailed protocol for testing commercial reference components with a reference laboratory test cell developed in-house by Fraunhofer ISE is presented. For evaluation of the protocol and the hardware, it was tested at three different institutions at the same time. Impedance spectroscopic and polarization data was acquired and analyzed. The obtained differences in performance were calculated to give the community an expectation window to compare own data to. Finally, the importance of a thorough temperature control and the conditioning phase are demonstrated.

Below ground carbon stock and carbon sequestration potentials of mangrove sediments in Eastern Niger Delta, Nigeria: Implication for climate change

The carbon sequestration capacity and climate change mitigation potentials of mangrove sediments in eastern Niger Delta were investigated. The aim was to determine the carbon stock in the sediments as a measure of carbon sequestration. A total of 312 sediment samples were obtained from 24 sampling 100 cm deep borings at seven locations using an open-cylindrical gouge auger of 100-cm length and 5-cm diameter. The procedures for field sampling, laboratory analysis and result presentation followed protocols for forest carbon measurement, monitoring and reporting. The lithology at the site, which is a major control on the distribution of organic carbon, included peat, peaty clay, and clayey peat with pockets of sands. Sediment bulk density (SBD), organic carbon concentration (%C), were used to estimate the organic carbon stock, carbon dioxide equivalent (CO2e), and to calculate carbon sequestration rate (CSR) and sequestration potential (CSP). Mean values of SBD were 1.30 g/cm3) and 12.48 %) respectively. Similarly, carbon averaged 39.80 Mg ha–1. The total carbon stock of the study area was estimated at 199,617.36 ± 55.64 Mg C, equivalent to 732,595.71 ± 55.64 Mg CO2. CSR was estimated at 4.54 g C cm–2 yr–1 while CSP of mangrove sediments was estimated at 21.56 Mg C yr–1. The result showed that 732,595.71 ± 55.64 Mg of carbon dioxide could either be removed or released to the atmosphere by the mangrove forest of Niger Delta through forest management practices and/or degradation. The study reinforces the need for the protection of mangroves against all anthropogenic-related degradation to improve carbon sequestration potential and achieve target in line with Sustainable Development Goal 13.

GUI-Based Data Visualisation Tool for Option C IPMVP using Jupyter Notebook

IPMVP is an acronym for International Performance Measurement and Verification Protocol, used for calculating energy savings by taking some external factors into account to give an equal base for a linear comparison between two periods. However, determining the significant independent variable for routine adjustment causes inconvenient repeated action of regression analysis modeling, which leads to the exhaustive calculation and human error risk. These exasperating actions led to the creation of this project, which aims to provide a user-friendly, insightful, and accurate energy-saving calculation program tool. Thus, the main objective of this project is to develop an energy-saving computational tool for option C IPMVP using web-based data analytic tools to improve efficiency and accuracy in each project. This paper used a web-based mathematical computation, Jupyter Notebook, to determine the significant independent variable for routine adjustment of the adjusted baseline. The program tool was validated using V-model software verification and validation methodology based on IEEE 1012 standards. The study can be concluded that the exhaustive calculation to determine the energy saving based on IPMVP standards can be significantly reduced with precision values at 50%, 80%, 90%, and 95% confidence levels using the proposed program which is equipped with insightful graphs and a user-friendly interface.

Full counting statistics as probe of measurement-induced transitions in the quantum Ising chain

Non-equilibrium dynamics of many-body quantum systems under the effect of measurement protocols is attracting an increasing amount of attention. It has been recently revealed that measurements may induce different non-equilibrium regimes and an abrupt change in the scaling-law of the bipartite entanglement entropy. However, our understanding of how these regimes appear{, how they affect the statistics of local quantities and}, finally whether they survive in the thermodynamic limit, is much less established. Here we investigate measurement-induced phase transitions in the Quantum Ising chain coupled to a monitoring environment. In particular we show that local projective measurements induce a quantitative modification of the out-of-equilibrium probability distribution function of the local magnetization. Starting from a GHZ state, the relaxation of the paramagnetic and the ferromagnetic order is analysed. In particular we describe how the probability distributions associated to them show different behaviour depending on the measurement rate.

A methodology for measuring heat transfer coefficient and self-similarity of thermal regulation in microvascular material systems

Fluid transport through microvascular networks—a hallmark for homeostasis in living systems—has transcended to engineered materials, primarily made possible because of modern manufacturing advancements. Vascular-enabled multifunctionality, including thermal regulation and self-healing, holds great potential for extending the lifetime of structural materials and expanding the operational envelope. Prior studies on vascular-based active cooling use a “combined” heat transfer coefficient (HTC): a single parameter lumps convection and radiation effects. Although the resulting mathematical models are linear—an attractive feature for computational modeling, the combined coefficient approach may not be accurate or even applicable if the operating temperature is unknown, which is the case with many thermal regulation applications (e.g., space probes). In this paper, we illustrate the remarked limitations of the lumped approach and advocate the need to use a decoupled HTC by splitting convective and radiative heat transfer modes. We show the broad applicability of the proposed method by applying it to three material systems: glass and carbon fiber-reinforced polymer composites and an additive manufactured metal. We show, using numerical simulations, the differences in the predictions from the decoupled approach with that of the combined HTC; these differences are prominent at higher heat fluxes. Also, the decoupling has enabled us to establish a scaling law that allows transferring of solutions fields across material systems, strengthening further the validity and utility of our approach. This work's significance is two-fold. First, the research is fundamental, providing accurate measurement protocols for critical model parameters. Second, this work facilitates the development of mathematical models for vascular-based thermal regulation that are predictive even for hostile environments (which are often difficult to realize in laboratories), such as outer space.

Cracks Classification using Acoustic Emission Technique on a Reinforced Concrete Beam

The usage of non-destructive techniques for structure's state assessment is highly desirable because they offer the possibility to monitor continuously and in a non-invasive manner the sign of failures of any structure. Among the several techniques proposed over the years, Acoustic Emission (AE) seems very promising. Such a technique, which applies to various materials, consents to the evaluation of micro-fractures generated during failure by detecting their acoustic emission through sensors located on the surface of the material itself. Concrete beam failure is suitable for such kind of procedure. It has been widely investigated through AE, but despite the many literature contributes, there still is a scarcity of practical applications on real structures, and no consensus on protocols. In this work, an AE technique has been paired with a four-point bending test to try and find a robust and reliable experimental setup for AE application on concrete beams. Results show a proper classification of the occurring cracks, which change according to different zones of the concrete beam and different load values. Axial crack signals exhibit different features concerning shear crack ones. In such a way, the categorization of damages can be performed and crosschecked with the theoretical expectations. All these results suggest that the proposed setup can be used as a possible protocol for practical AE measurements.

Methane venting from uncontrolled production storage tanks at conventional oil wells—Temporal variability, root causes, and implications for measurement

Uncontrolled oil production storage tanks are important but poorly understood sources of methane (CH4) emissions in the upstream oil and gas sector. This study reports and analyzes directly measured, temporally varying CH4 emission rates, total gas vent rates, and vent gas CH4 fractions from storage tanks at eight active upstream oil production sites in Alberta, Canada. Using a built-for-purpose optical mass flux meter (VentX) supplemented by an ultrasonic flow meter and quantitative optical gas imaging camera where possible, mean vent rates (whole gas) among tanks in the study ranged from 37 to 598 m3/d; however, at some individual tanks, instantaneous flow rates could vary significantly from 0 to over 4,000 m3/d for minutes at a time, while unsteady CH4 volume fractions varied by up to 41% absolute. Root cause analysis revealed the limits of estimating vented emissions from oil production volumes using an assumed gas–oil ratio, especially in cases where produced gas from wells fully or partially bypasses separators. The analysis of the acquired data also demonstrated how 1-h duration vent measurements recommended in some regulations are insufficient to reliably estimate emissions from unsteady tanks. These two factors are the likely reason for significantly underreported vent rates in the present sample and are thought to be a key cause of the mismeasurement/underestimation of tank venting that has driven persistent gaps between bottom-up inventories and top-down measurements. Finally, detailed statistical analyses were completed to suggest minimum sampling durations and instrumentation requirements for direct measurements of tanks and minimum sample sizes for discrete (“snapshot”) surveys of both individual tanks and multitank surveys under different scenarios. Results show that caution is warranted when interpreting snapshot measurements of individual tanks, but aggregate emissions of multiple tanks should be accurately measurable with readily achievable sample sizes. These results are expected to be especially valuable to ongoing efforts seeking to develop robust protocols for gas certification and measurement, reporting, and verification (MRV) of CH4 emissions in the oil and gas sector.

Emergence of field-induced memory effect in spin ices

Out-of-equilibrium investigation of strongly correlated materials deciphers the hidden equilibrium properties. Herein, we have investigated the out-of-equilibrium magnetic properties of polycrystalline Dy2Ti2O7 and Ho2Ti2O7 spin ices. Our experimental findings reveal the emergence of magnetic field-induced anomalous hysteresis observed solely in temperature-and magnetic field-dependent AC susceptibility measurements. The observed memory effect (anomalous thermomagnetic hysteresis) exhibits a strong dependence on both thermal and non-thermal driving variables. Owing to the non-collinear spin structure, the applied DC bias magnetic field produces quenched disorder sites in the cooperative Ising spin matrix and suppresses the spin–phonon coupling. These quench disorders create a dynamic spin correlation, having slow spin relaxation and quick decay time, which additionally contribute to AC susceptibility. The initial conditions and measurement protocol decide the magnitude and sign of this dynamical term contributing to AC susceptibility. It is being suggested that such out-of-equilibrium properties arise from the combined influences of geometric frustration, disorder, and the cooperative nature of spin dynamics exhibited by these materials.

Challenges for geomechanical laboratory analyses of claystones with regard to the time frame of the site selection process

Abstract. The current programme for the site selection process in Germany schedules 11 months for geomechanical laboratory tests per potential future site (BGE, 2022). For the laboratory analysis of rock salt, this time frame seems realistic as no hydromechanical coupling has to be taken into account. In the case of a crystalline basement, the intact rock matrix is low permeable, but transport processes are dominated by ubiquitous fracture networks, which are hard to capture in laboratory settings. Thus, the effect that hydromechanical coupling in low permeable rock has on the speed of laboratory measurements will probably be no problem. However, for claystones, the geomechanical processes within the rock matrix strongly depend on the hydromechanical coupling, which thus determines the speed with which, for example, loading ramps can be applied in the laboratory. The need to maintain the pore pressure equilibrium during the experiments in order to know the acting effective stresses slows down the speed of the measurements significantly. Given the tight time frame of 11 months and the numerous parameters which have to be analysed according to law (StandAG, 2017), the low speed with which the experiments can be performed represents a severe hindrance. It is thus important to establish measurement protocols which enable the simultaneous determination of several parameters in order to save time. Based on our experience with experiments on Opalinus Clay, we offer a first idea of how such a measurement protocol could look and would like to invite a discussion on how to optimise experiments on claystones further in order to have a chance to meet the very tight time frame required by the site selection process.

Multiplexing System for Automated Characterization of a Capacitive Field‐Effect Sensor Array

In comparison to single‐analyte devices, multiplexed systems for a multianalyte detection offer a reduced assay time and sample volume, low cost, and high throughput. Herein, a multiplexing platform for an automated quasi‐simultaneous characterization of multiple (up to 16) capacitive field‐effect sensors by the capacitive–voltage (C–V) and the constant‐capacitance (ConCap) mode is presented. The sensors are mounted in a newly designed multicell arrangement with one common reference electrode and are electrically connected to the impedance analyzer via the base station. A Python script for the automated characterization of the sensors executes the user‐defined measurement protocol. The developed multiplexing system is tested for pH measurements and the label‐free detection of ligand‐stabilized, charged gold nanoparticles.

First detection probability in quantum resetting via random projective measurements

We provide a general framework to compute the probability distribution of the first detection time of a ‘state of interest’ in a closed quantum system subjected to random projective measurements. In our ‘quantum resetting’ protocol, resetting of a state is not implemented by an additional classical stochastic move, but rather by the random projective measurement. We then apply this general framework to Poissonian measurement protocol with a constant rate r and demonstrate that exact results for can be obtained for a generic two level system. Interestingly, the result depends crucially on the detection schemes involved and we have studied two complementary schemes, where the state of interest either coincides or differs from the initial state. We show that at short times vanishes universally as as t → 0 in the first scheme, while it approaches a constant as t → 0 in the second scheme. The mean first detection time, as a function of the measurement rate r, also shows rather different behaviors in the two schemes. In the former, the mean detection time is a non-monotonic function of r with a single minimum at an optimal value , while in the later, it is a monotonically decreasing function of r, signaling the absence of a finite optimal value. These general predictions for arbitrary two level systems are then verified via explicit computation in the Jaynes–Cummings model of light–matter interaction. We also generalize our results to non-Poissonian measurement protocols with a renewal structure where the intervals between successive independent measurements are distributed via a general distribution and show that the short time behavior of is universal as long as . This universal t 2 law emerges from purely quantum dynamics that dominates at early times.

Quantum Logic Enhanced Sensing in Solid-State Spin Ensembles.

We demonstrate quantum logic enhanced sensitivity for a macroscopic ensemble of solid-state, hybrid two-qubit sensors. We achieve over a factor of 30 improvement in the single-shot signal-to-noise ratio, translating to an ac magnetic field sensitivity enhancement exceeding an order of magnitude for time-averaged measurements. Using the electronic spins of nitrogen vacancy (NV) centers in diamond as sensors, we leverage the on-site nitrogen nuclear spins of the NV centers as memory qubits, in combination with homogeneous and stable bias and control fields, ensuring that all of the ∼10^{9} two-qubit sensors are sufficiently identical to permit global control of the NV ensemble spin states. We find quantum logic sensitivity enhancement for multiple measurement protocols with varying optimal sensing intervals, including XY8 and DROID-60 dynamical decoupling, as well as correlation spectroscopy, using an applied ac magnetic field signal. The results are independent of the nature of the target signal and broadly applicable to measurements using NV centers and other solid-state spin ensembles. This work provides a benchmark for macroscopic ensembles of quantum sensors that employ quantum logic or quantum error correction algorithms for enhanced sensitivity.

2-D Localization System for Mobile IoT Devices Using a Single Wi-Fi Access Point With a Passive Frequency-Scanned Antenna

A novel two-dimensional indoor location system for IoT devices employing a single Wi-Fi Access Point is presented. The x, y position is estimated with a combination of Directionof-Arrival (DoA) and Time-of-Flight (ToF) algorithms. The azimuthal DoA is estimated using a modified MUSIC technique, which requires the acquisition of the Received Signal Strength Indicator (RSSI) using different Wi-Fi frequency channels in the 2.4 GHz band, together with a dual-port frequency-scanning antenna (FSA). This allows a wide Field-of-View (FoV) of 180: for the DoA. To estimate the ranging distance, an algorithm based in the 802.11mc Fine Time Measurement (FTM) protocol is employed to consider the effects of the channel hopping. Therefore, the proposed system does not rely on Channel State Information (CSI) or complex IQ information, which is not available in commercial Wi-Fi APs. The proposed system has been fully implemented with a commercial Wi-Fi AP and tested in a practical scenario, proving a root-mean-square error (RMSE) when estimating the localization of mobile devices of only 1.43m, in a wide area of 12 m x 12 m.