National Institute Of Science And Technology Research Articles

Effect of dense plasma environment and external magnetic field on atomic structure and radiative properties of Ar XVII

Atomic structures and radiative properties of He like Ar XVII in the presence of dense plasma environments and external magnetic field have been presented within the framework of the relativistic theory. For this purpose, the relativistic configuration interaction method by incorporating the generalized b-potential and external magnetic field has been implemented. Plasma screening effect on 1s2 1S0 → 1s2p 3P1 transitions of Ar XVII ion in the presence of an external magnetic field has been investigated. We also studied the Zeeman splitted energies and predicted the excitation energies of Ar XVII ion for the magnetic sublevels 1s2p 3P0 (MJ = 0), 3P1 (MJ = 0, ±1), 3P2 (MJ = 0, ±1, ±2), 1P1 (MJ =0, ±1). Our calculated results are in excellent agreement with National Institute of Science and Technology (NIST) database and other theoretical available data.

Efficient and secure hybrid chaotic key generation for light encryption device block cipher

Lightweight cryptographic algorithms must develop to ensure the confidentiality and integrity of the data in resource-constrained devices. Keys are vital to every cryptography algorithm because they provide randomness, complexity, unexpected nature, and robustness. A light encryption device (LED) is considered a lighter version of advanced encryption standard (AES), but it is vulnerable to related key attacks due to using the same key during the whole encryption process. This paper presents a hybrid chaotic key generator (HCKG) based on 3D Lorenz, and 2D Henon maps to generate a highly randomized key that combines with the LED to provide a high level of secure encryption on resource-constrained devices. We modified the HCKG every four rounds via simple operations to get the subkeys and XORed it with the state to increase the complexity of the ciphertext. Moreover, the HCKG with subkeys allows us to decrease the total number of LED rounds from 32 to 24 to minimize the calculation cost while maintaining a high level of security. National Institute of Science and Technology (NIST) test suite proves that the proposed LED-HCKG demonstrates a high-performance increase by nearly 0.3283 higher than LED concerning data integrity and secrecy.

Dynamic Ag nanoclusters inside atomically thin SiOx enable stochastic memristors for physical unclonable functions

We propose a stochastic memristor utilizing ultrathin native-SiOx films (∼2.7 nm) and dynamic Ag nanoclusters for constructing physical unclonable function (PUF) hardware. The atomically thin solid electrolyte allows for quantum-mechanical tunneling current at high resistance states, which exponentially increases the entropy between separated devices. This results in good uniformity (54.4%), uniqueness (53.7%), and reliability (98.75%) for the prototype native-SiOx mem-PUF array. Furthermore, the proposed device demonstrates reconfigurability for key refreshing and passes all 15 National Institute of Science and Technology (NIST) tests, verifying the high randomness of the generated bits. Overall, this work highlights the potential of the ultrathin native-SiOx memristor for PUF applications.

Neurotoxicity of Diesel Exhaust Particles.

Air pollution particulate matter (PM) is strongly associated with risks of accelerated cognitive decline, dementia and Alzheimer's disease. Ambient PM batches have variable neurotoxicity by collection site and season, which limits replicability of findings within and between research groups for analysis of mechanisms and interventions. Diesel exhaust particles (DEP) offer a replicable model that we define in further detail. Define dose- and time course neurotoxic responses of mice to DEP from the National Institute of Science and Technology (NIST) for neurotoxic responses shared by DEP and ambient PM. For dose-response, adult C57BL/6 male mice were exposed to 0, 25, 50, and 100μg/m3 of re-aerosolized DEP (NIST SRM 2975) for 5 h. Then, mice were exposed to 100μg/m3 DEP for 5, 100, and 200 h and assayed for amyloid-β peptides, inflammation, oxidative damage, and microglial activity and morphology. DEP exposure at 100μg/m3 for 5 h, but not lower doses, caused oxidative damage, complement and microglia activation in cerebral cortex and corpus callosum. Longer DEP exposure for 8 weeks/200 h caused further oxidative damage, increased soluble Aβ, white matter injury, and microglial soma enlargement that differed by cortical layer. Exposure to 100μg/m3 DEP NIST SRM 2975 caused robust neurotoxic responses that are shared with prior studies using DEP or ambient PM0.2. DEP provides a replicable model to study neurotoxic mechanisms of ambient PM and interventions relevant to cognitive decline and dementia.

Effect of plasma environment on spectral and structural properties of H-like C, N and O ions

The novel studies of the dense plasma on transition properties and level structures for H-like Carbon, Nitrogen and Oxygen ions are presented. Plasma effect is included through the confined ion sphere plasma model. We have also included relativistic effects through mass-correction, Darwin and spin-orbit terms during the calculation. The energy level shift, oscillator strengths, transition rates, plasma shifts and probability densities are calculated by using Ritz’s variation method for different ion sphere plasma concentrations. The variation parameters are calculated by minimizing the expectation value of the energy. Eigenstate, probability and average position are calculated with plasma concentration for the internal structure of the system. We have compared our calculated data with experimental National Institute of Science and Technology (NIST) database and other theoretical results in the literature and it is showing a good quantitative agreement. The study may be very useful in astrophysical and fusion plasma.

Quantifying Turing: a systems approach to quantitatively assessing the degree of autonomy of any system

This paper describes a method by which the degree of autonomy of a system can be quantified in a manner that allows comparison between systems. The methodology revisits, refines, and extends the contextual autonomous capability (CAC) model proposed by the National Institute of Science and Technology (NIST) by defining three orthogonal system metrics against which the performance of a system may be assessed. During the development of this model, it was recognized that there existed two different but coupled domains of autonomy — the Executive Autonomy describing the degree of independence of a system during the execution of the mission; and the Developmental Autonomy describing the degree of independence of the system during preparation for the mission. The resulting methodology is explicitly developed to be system agnostic such that it could be applied to humans as well as computerized systems. As such, it provides a means of quantifiably comparing the performance of any two systems — including human and computer — that are performing comparable sets of missions. The proposed model is called the system-agnostic quantification of autonomy levels (SQuAL) model.

Ion chromatography as candidate reference method for the determination of chloride in human serum.

BackgroundWe developed an ion chromatography (IC) method for measurement of chloride in human serum which was regarded as a simple, rapid, accurate, and sensitive technique. The method will be hopefully selected as a candidate reference method.MethodSerum aliquots of 0.1 mL were diluted 500 times with Milli‐Q water, and chloride in serum samples was measured by IC with a gradient elution procedure using a KOH eluent generator.ResultsBased on the data, chloride in human serum was well detected by IC. The calibration curve for chloride was linear in the concentration range from 0 to 0.42 mmol/L with a correlation coefficient of .99995 under the optimum experimental conditions. The chloride concentration had a good linear relationship with the peak areas of chloride. This method was sensitive because of the low limit of detection (LOD) and the low limit of quantification (LOQ) 9.87 × 10−5 mmol/L and 3.27 × 10−4 mmol/L, respectively. Besides, the method was highly precise with the within‐run coefficient of variations (CVs) for the measurement of low, medium, and high concentration level samples 0.32%, 0.73%, and 0.50%. As for the evaluation of accuracy, the biases were less than ±1% and 2% by comparing with National Institute of Science and Technology (NIST) standard material SRM 956d and 2013‐2018 IFCC‐RELA samples, respectively. Finally, the biases between IC method and the inductively coupled plasma mass spectrometry (ICP‐MS) method were less than 1% which showed good agreement.ConclusionIon chromatography is a simple sample treatment procedure for the determination of chloride in human serum with high sensitivity and specificity. The proposed method could be recommended as a candidate reference method for the determination of serum chloride in human serum.

Relativistic double-ionization equation-of-motion coupled-cluster method: Application to low-lying doubly ionized states.

This article deals with the extension of the relativistic double-ionization equation-of-motion coupled-cluster (DI-EOMCC) method [H. Pathak et al. Phys. Rev. A 90, 010501(R) (2014)] for the molecular systems. The Dirac-Coulomb Hamiltonian with four-component spinors is considered to take care of the relativistic effects. The implemented method is employed to compute a few low-lying doubly ionized states of noble gas atoms (Ar, Kr, Xe, and Rn) and Cl2, Br2, HBr, and HI. Additionally, we presented results with two intermediate schemes in the four-component relativistic DI-EOMCC framework to understand the role of electron correlation. The computed double ionization spectra for the atomic systems are compared with the values from the non-relativistic DI-EOMCC method with spin-orbit coupling [Z. Wang et al. J. Chem. Phys. 142, 144109 (2015)] and the values from the National Institute of Science and Technology (NIST) database. Our atomic results are found to be in good agreement with the NIST values. Furthermore, the obtained results for the molecular systems agree well with the available experimental values.

Re-Os geochronology for the NIST RM 8505 crude oil: The importance of analytical protocol and uncertainty

The National Institute of Science and Technology (NIST) research material (RM) 8505 is a Venezuelan crude oil certified for its vanadium concentration. It has recently been proposed as a matrix-matched standard for interlaboratory comparison of Re-Os isotopic analyses while serving as a benchmark for petroleum-based Re-Os method development. Here, the NIST RM 8505 oil is characterized using a multi-solvent asphaltene precipitation, permitting interlaboratory Re-Os data comparison and evaluation of techniques used to derive Re-Os isochron ages. We present a detailed discussion of analytical blank sources, critical evaluation of analytical uncertainties, method improvements and data corrections. Additionally, we provide a comprehensive discussion on the effect of data population size and analytical uncertainty on isochron statistics and the robustness of isochron ages. In addition to NIST RM 8505 (2.43 ± 0.15 ng/g Re, 30.0 ± 0.7 pg/g Os), we provide the first Re-Os data for NIST SRM 1634c (1.73 ± 0.01 ng/g Re, 32.5 ± 0.8 pg/g Os) and EnviroMAT SCP Science (39 ± 1 pg/g Re, 1.01 ± 0.02 pg/g Os), two other commercially available hydrocarbon trace metal standards.The application of several asphaltene (ASPH) precipitations using different n-alkane solvents (pentane, heptane and decane) for the NIST RM 8505 significantly improved the spread of data in the 187Re/188Os-187Os/188Os space. Multi-solvent asphaltene precipitations yield an asphaltene-only Model 1 isochron (75 ± 24 Ma) and the maltene-crude oil-asphaltene triplets yield a more precise Model 1 isochron age of 78.5 ± 2.3 Ma with a 187Os/188Osinitial of 0.877 ± 0.021. Our age is considerably older compared to a previously reported Model 1 age of 62.7 ± 5.7 Ma based on C7 ASPH-crude oil-MALT triplets (Liu and Selby, 2017) and considerably younger than the Model 1 age of 98.4 ± 9.5 Ma based on ASPH separates (Liu et al., 2019). The analytical reasons leading to these age differences are discussed in this paper.The geological context for the NIST 8505 oil is unknown, therefore we use trace metal data (Ni, V, Fe, Mo, etc.) to derive plausible constraints for the origin of this oil. The NIST 8505 oil shows trace metal data similar to published data for oils from the Urdaneta district, the La Paz, Mara and Lagunillas oil fields and source rocks of the La Luna Formation in the Maracaibo Basin, Venezuela. In this geological context, our ~79 Ma age for the NIST 8505 oil implies a Late Cretaceous early hydrocarbon generation event from older Upper Cretaceous source rocks and overlaps with the youngest age of potential source rocks in the Maracaibo Basin. However, the age of large-scale oil generation in the Maracaibo Basin is significantly younger, lasting from the Oligocene to the Pliocene.

Experimental realization of more quantum randomness generation based on non-projective measurement

Quantum random numbers are fundamental resources (Rev. Mod. Phys. 89 015004) for the fields of communications and information security. Usually, projective measurements can be applied on a two-qubit entangled state to generate quantum random numbers. However, it cannot certify more than one bit of randomness for one set of measurements. On contrast, non-projective measurements in-principle may be able to generate more random bits, and therefore show some merits among present methods. Here, we report the implementation of a quantum random number generator based on a symmetric informationally complete positive operator-valued measure. In our experiment, we prepare a maximally entangled state of two-qubits through spontaneous parametric down-conversion processes, and observe the violation of Gisin’s elegant Bell inequality with the value of 6.8138 ± 0.0822, exceeding the classical bound of 6. Through randomness extractors, including a Toeplitz extractor and a parallel linear feedback shift register based extractor, we finally extract a random string with an autocorrelation coefficient below 10−3 and the string can pass all randomness tests of the National Institute of Science and Technology (NIST).

Quantitative Lipoprotein Subclass and Low Molecular Weight Metabolite Analysis in Human Serum and Plasma by 1H NMR Spectroscopy in a Multilaboratory Trial.

We report an extensive 600 MHz NMR trial of quantitative lipoprotein and small-molecule measurements in human blood serum and plasma. Five centers with eleven 600 MHz NMR spectrometers were used to analyze 98 samples including 20 quality controls (QCs), 37 commercially sourced, paired serum and plasma samples, and two National Institute of Science and Technology (NIST) reference material 1951c replicates. Samples were analyzed using rigorous protocols for sample preparation and experimental acquisition. A commercial lipoprotein subclass analysis was used to quantify 105 lipoprotein subclasses and 24 low molecular weight metabolites from the NMR spectra. For all spectrometers, the instrument specific variance in measuring internal QCs was lower than the percentage described by the National Cholesterol Education Program (NCEP) criteria for lipid testing [triglycerides <2.7%; cholesterol <2.8%; low-density lipoprotein (LDL) cholesterol <2.8%; high-density lipoprotein (HDL) cholesterol <2.3%], showing exceptional reproducibility for direct quantitation of lipoproteins in both matrixes. The average relative standard deviations (RSDs) for the 105 lipoprotein parameters in the 11 instruments were 4.6% and 3.9% for the two NIST samples, whereas they were 38% and 40% for the 37 commercially sourced plasmas and sera, respectively, showing negligible analytical compared to biological variation. The coefficient of variance (CV) obtained for the quantification of the small molecules across the 11 spectrometers was below 15% for 20 out of the 24 metabolites analyzed. This study provides further evidence of the suitability of NMR for high-throughput lipoprotein subcomponent analysis and small-molecule quantitation with the exceptional required reproducibility for clinical and other regulatory settings.

Dynamic Rounds Chaotic Block Cipher Based on Keyword Abstract Extraction.

According to the keyword abstract extraction function in the Natural Language Processing and Information Retrieval Sharing Platform (NLPIR), the design method of a dynamic rounds chaotic block cipher is presented in this paper, which takes into account both the security and efficiency. The cipher combines chaotic theory with the Feistel structure block cipher, and uses the randomness of chaotic sequence and the nonlinearity of chaotic S-box to dynamically generate encrypted rounds, realizing more numbers of dynamic rounds encryption for the important information marked by NLPIR, while less numbers of dynamic rounds encryption for the non-important information that is not marked. Through linear and differential cryptographic analysis, ciphertext information entropy, “0–1” balance and National Institute of Science and Technology (NIST) tests and the comparison with other traditional and lightweight block ciphers, the results indicate that the dynamic variety of encrypted rounds can achieve different levels of encryption for different information, which can achieve the purpose of enhancing the anti-attack ability and reducing the number of encrypted rounds. Therefore, the dynamic rounds chaotic block cipher can guarantee the security of information transmission and realize the lightweight of the cryptographic algorithm.

Coupled ocean–atmosphere modeling and predictions

AJMwas supported by theNSFEarth System Modeling Program (OCE1419306) and the NOAA Climate Variability and Prediction Program (NA14OAR4310276). HS thanks the Office of Naval Research for support under N00014-15-1-2588. LPP was supported by “Advanced Studies in Medium and High Latitudes Oceanography” (CAPES 23038.004304/2014-28) and “National Institute of Science andTechnology of the Cryosphere” (CNPq/PROANTAR704222/2009). VM was supported by NOAA grant NA12OAR4310078. TGJ was supported by the U. S. Naval Research Laboratory 6.2 project “Fresh Water Balance in the Coupled Ocean-Atmosphere System” (BE-435-040-62435N-6777) YHT was supported by the MOST grant 106-2111-M-002-001, Taiwan.

Secure by Design: Cybersecurity Extensions to Project Management Maturity Models for Critical Infrastructure Projects

Many systems that comprise our critical infrastructures – including electricity, transportation, healthcare, and financial systems – are designed and deployed as information technology (IT) projects using project management practices. IT projects provide a one-time opportunity to securely cybersecurity to the IT components of critical infrastructures. The project management maturity models used by organizations today to assess the quality and rigour of IT project management practices do not explicitly consider cybersecurity. This article makes three contributions to address this gap. First, it develops the argument that cybersecurity can and should be a concern of IT project managers and assessed in the same way as other project management capabilities. Second, it examines three widely used cybersecurity maturity models – i) the National Institute of Science and Technology (NIST) framework for improving critical infrastructure cybersecurity, ii) the United States Department of Energy’s Cybersecurity Capability Maturity Model (C2M2), and iii) the CERT Resilience Management Model (CERT RMM) from the Carnegie Mellon Software Engineering Institute – to identify six cybersecurity themes that are salient to IT project management. Third, it proposes a set of cybersecurity extensions to PjM3, a widely-deployed project management maturity model. The extensions take the form of a five-level cybersecurity capability perspective that augments the seven standard perspectives of the PjM3 by explicitly assessing project management capabilities that impact the six themes where IT project management and cybersecurity intersect. This article will be relevant to IT project managers, the top management teams of organizations that design and deploy IT systems for critical infrastructures, and managers at organizations that provide and maintain critical infrastructures. The challenge in the digital economy is that no chain is stronger than its weakest link.

Web service-based standards for biometrics interoperability

Tracey Caldwell interviews Kevin Mangold at the US National Institute of Science and Technology (NIST) about its work on the command and control of biometric capture devices via web services and the benefits of open and interoperable standards based on web services.

Numerical investigation of internal frost damage of digital cement paste samples with cohesive zone modeling and SEM microstructure characterization

This paper develops microstructure characterization and computational modeling approaches to investigate the internal-frost damage due to ice crystallization pressure. The three-dimensional (3D) cohesive zone modeling (CZM) techniques were used to simulate frost-induced damage behavior within digital cement samples under subcooling temperatures. The 3D CZM techniques were firstly applied to simulate crack propagation through multi-pore systems with compact tension tests. Then the multiphase 3D bilinear cohesive zone models were developed to investigate the internal frost damage due to ice crystallization pressure within heterogeneous cementitious samples. The pore microstructure within cement paste samples were characterized with the scanning electron microscope (SEM) imaging techniques. The 3D imaging reconstruction techniques developed by National Institute of Science and Technology (NIST) were applied to generate the 3D digital SEM samples for frost damage simulation. The pore pressure at subcooling temperatures was calculated with thermodynamic analysis. The calculated pore pressure was input for crack initiation and propagation simulation with the 3D CZM. The predicted internal frost damage within SEM digital samples was compared with captured damage in actual specimens. The favorably predicted crack paths with digital samples indicate that the developed micromechanical analysis techniques have the ability to predict the internal frost damage. This study also showed that the pore pressure due to ice crystallization is sufficient to cause internal damage during freeze–thaw cycles.

Acoustic Factor Analysis for Robust Speaker Verification

Factor analysis based channel mismatch compensation methods for speaker recognition are based on the assumption that speaker/utterance dependent Gaussian Mixture Model (GMM) mean super-vectors can be constrained to reside in a lower dimensional subspace. This approach does not consider the fact that conventional acoustic feature vectors also reside in a lower dimensional manifold of the feature space, when feature covariance matrices contain close to zero eigenvalues. In this study, based on observations of the covariance structure of acoustic features, we propose a factor analysis modeling scheme in the acoustic feature space instead of the super-vector space and derive a mixture dependent feature transformation. We demonstrate how this single linear transformation performs feature dimensionality reduction, de-correlation, normalization and enhancement, at once. The proposed transformation is shown to be closely related to signal subspace based speech enhancement schemes. In contrast to traditional front-end mixture dependent feature transformations, where feature alignment is performed using the highest scoring mixture, the proposed transformation is integrated within the speaker recognition system using a probabilistic feature alignment technique, which nullifies the need for regenerating the features/retraining the Universal Background Model (UBM). Incorporating the proposed method with a state-of-the-art i-vector and Gaussian Probabilistic Linear Discriminant Analysis (PLDA) framework, we perform evaluations on National Institute of Science and Technology (NIST) Speaker Recognition Evaluation (SRE) 2010 core telephone and microphone tasks. The experimental results demonstrate the superiority of the proposed scheme compared to both full-covariance and diagonal covariance UBM based systems. Simple equal-weight fusion of baseline and proposed systems also yield significant performance gains.

Safety enhancements of home lift, position and rehabilitation (HLPR) chair

According to recent studies published in AI Magazine (2005), in 2000, "people aged 65 and older made up 12.3 percent of the U.S. population, while by 2030, they will constitute 19.2 percent, after which growth is projected to level off so that this cohort represents 20 percent of the population in 2050." In response to respective needs, the National Institute of Science and Technology (NIST), Intelligent Systems Division, began the Healthcare Mobility Project to address this healthcare issue of patient lift and mobility, and began developing the Home Lift, Position, &amp; Rehabilitation (HLPR) chair to investigate specific areas of mobility and rehabilitation. The HLPR chair has been built as a prototype but a significant number of unresolved issues exist and are being researched. The objective of this particular project is to investigate the computer and software safety issues in the design, implementation and use of the HLPR chair.

ICP-OES and ICP-MS for the Determination of Metals: Application to Oysters

This mini-review gives a general overview of inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) for the determination of metals in oysters. A brief description of the basic principles, instrumentation, and recent developments is provided. A comparison and selected applications of these two analytical techniques for metal determination in oysters is presented. It was noted that the National Institute of Science and Technology (NIST) standard reference materials (SRM 1556b, Oyster Tissue) were frequently used for accuracy studies in a wide variety of reports.

Computational Toolset for X-Ray Spectral Analysis

We have designed a computational tool for generating X-ray photon spectra for a range of applications both in diagnostic radiology and mammography. As a library, we have adapted the spectral data based on the interpolating polynomials methods by Boone et al [5,6] as well as the computer data files given by Cranley et al [8]. The attenuated spectra for element or compound materials can be calculated based on the mass-attenuation coefficients from NIST (National Institute of Science and Technology), which were also incorporated as a database. Furthermore, a function that a user can generate any filter material by editing the NIST data has been implemented. Parameters related to the beam quality, such as mean photon energy, fluence, exposure, half-value layer (HVL), etc., are considered as important outputs. All of functions and database are integrated in a form of graphical user interface (GUI) by using Microsoft Visual C++TM. This self-developed spectrum-generating code can be usefully served to design X-ray sensors. In this study, we have applied the code to estimate quantum efficiency and charge collection efficiency in various detector materials.