Search

The compound 3,4‐diaminopyridine (3,4‐AP), a derivative of 4‐aminopyridine (4‐AP), is used in the symptomatic treatment of fatigue in multiple sclerosis as well as Lambert–Eaton myasthenia syndrome whereas the parent compound 4‐AP is used as an acetylcholine‐releasing drug, in serum, saliva, and urine. 4‐AP is an experimental drug that may reduce symptoms in some people with multiple sclerosis, particularly those who are more sensitive to heat. The carbon nanotubes (CNTs) have inside cavity tethering on the surface upon functionalization and adsorption on the walls of CNTs, which provides extra ability to carry pharmaceutical agents through multiple ways. Due to these benefits, this communication will discuss the comparative changes in geometry, electronic properties, and shielding parameters of 4‐AP and 3,4‐AP absorbed C56H16. The DFT/B3LYP/6–31G (d, p) method is used for the first time to report electronic structure and interaction parameters on the CNT surface. The same level theory is used to discuss the thermodynamic stability of CNT‐4‐AP/3,4‐AP. The calculated UV spectra of CNT are compared with UV spectra of CNT‐4‐AP and 3,4‐AP by using the same level theory in a water solvent, which provides a better comprehension of CNT as a drug delivery system after absorption of the 4‐AP and 3,4‐AP in the human body. The nature and strength of interactions have been discussed with the help of AIM analysis, and the frontier orbital highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap, chemical softness, and chemical hardness have been calculated to understand its complete chemical properties. The characters of the frontier molecular orbitals are discussed and analyzed by comparing the DOS spectra of CNT with CNT‐4‐AP/3,4‐AP. [ABSTRACT FROM AUTHOR]

Existential humanistic therapy is a collaborative journey shared by a client and a therapist to ease clients' suffering and to expand their self-awareness, consciousness, and ability to change. As part of this therapeutic journey, the experience of awe may be an important component. Indian classical music can bring about an experience of awe and is examined in this article through the lens of existential humanistic psychotherapy as a relatively unexplored avenue for deep healing. [ABSTRACT FROM AUTHOR]

Existential psychotherapy places existential issues at the centerpiece of an individual's psychological health. In many ways, it is an iconoclastic approach to dealing with mental health issues that is premised on strong fundamentals of philosophy. Poetry has also been performing a similar task of healing individuals by enabling them to access their deeper levels of self. It combines the linguistic, cultural, spiritual, and intellectual heritage of its source of origin along with universal givens to create distinct and fascinating patterns of similar eternal truths. This article explores the aura and mystique of Urdu poetry as a healing tradition in an existential-humanistic sense. [ABSTRACT FROM AUTHOR]

Organizational discourse is getting hyped and exaggerated about leadership. This results in shifting of rational preferences about leadership into absolutist musts. These hardened beliefs enter into the cognitive processes of the individuals at work places and thereby result in dysfunctional organizational behavior and high psychological stress. This study applies the cognitive psychotherapeutic framework of the rational emotive behavior therapy to discuss the implications of such beliefs in an organizational context. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Cyclic ordering was observed in high energy ball milled Fe 2.1 Cr 0.9 Al alloys. • Stored energy during milling was evaluated using a reaction rate model. • Enhancement in magnetization and relative cooling power was noted. • Extended X-ray absorption fine structure studies reveal short range order. • Ball milling can effectively improve magnetic and magnetocaloric properties. Abstract Current research on magnetocaloric materials (MCM) aims at developing low cost, environmentally friendly materials which can be manufactured by simple processes. We report the effect of high energy ball milling on the structural, magnetic and magnetocaloric properties of low cost Fe 2.1 Cr 0.9 Al alloys. The degree of structural order in the Fe-Cr sublattice was found to vary with milling time in a cyclic fashion at a milling speed of 600 rpm. This phenomenon was analyzed by a reaction rate model based on the stored energy during high energy milling. The sample possessed a B2 crystal structure before milling. Milling for 15 min. at 600 rpm induced structural changes to produce a L2 1 structure. Interestingly, the 15 min. milled sample exhibited ∼50% higher saturation magnetization (M S) compared to the value before milling. The relative cooling power (RCP) also increased to 300 Jkg−1 at 5 T, compared to a value of 244 Jkg−1 before milling. Extended X-ray absorption fine structure (EXAFS) studies revealed the emergence of short range order in the milled samples. [ABSTRACT FROM AUTHOR]

The Moon has a large potential for space exploration and mining valuable resources. In particular, 3He provides rich sources of non-radioactive fusion fuel to fulfill cislunar and Earth's energy demands, if found economically feasible. The present study focuses on developing advanced techniques to prospect 3He resources on the Moon from multi-sensor remote sensing perspectives. It characterizes optical changes in regolith materials due to space weathering as a new retention parameter and introduces a novel machine learning inversion model for retrieving the physical properties of the regolith. Our analysis suggests that the reddening of the soil predominantly governs the retention, along with attenuated mafic band depths. Moreover, semi-variograms show that the spatial variability of 3He is aligned with the episodic weathering events at different timescales. We also observed that pyroclastic regoliths with high dielectric constant and increased surface scattering mechanisms exhibited a 3He abundant region. For ejecta cover, the retention was weakly associated with the dielectric contrast and a circular polarization ratio (CPR), mainly because of the 3He-deficient nature of the regolith. Furthermore, cross-variograms revealed inherent cyclicity attributed to the sequential process of weathering effects. Our study provides new insights into the physical nature and near-surface alterations of lunar regoliths that influence the spatial distribution and retention of solar wind implanted 3He. [ABSTRACT FROM AUTHOR]

• ' cos α ' method combined with 2DXRD is a novel technique for rapid stress analysis. • Accuracy of this technique depends strongly on some key measurement parameters. • These include X-ray incidence angle, sample-detector distance and beam spot size. • We report how the above parameters can be optimized to obtain accurate stress data. • This can help in establishing proper protocols for ' cos α ' method of stress analysis. Application of ' cos α ' method using portable 2DXRD instruments has attracted considerable attention for rapid, in-line residual stress measurements. However, the validity of this technique has often been questioned, particularly under field conditions, because the mechanisms of how critical measurement parameters such as sample-to-detector distance and X-ray incidence angle affect the accuracy of measured residual stress is not adequately understood. To address this issue, near-surface residual stress in a shot-peened AISI 4140 alloy coupon was determined using ' cos α ' method for a wide range of sample-to-detector distances and incidence angles – this data was then compared with the data from conventional ' sin 2 ψ ' technique. Results showed that there exists a window of incidence angles for which the values of residual stress from 2DXRD are reliable. However, outside of this window, data loses accuracy due to beam defocusing and errors in determining its orientation with respect to diffracting crystallites. Unlike incidence angle, the impact of sample-to-detector distance on the accuracy of residual stress was found to be less significant, as it only changed the size of the Debye ring and did not affect its distortion. Results also showed that increase in beam size can reduce the exposure time required for data collection, but it comes at the cost of sacrificing the intrinsic resolution and signal-to-noise ratio (SNR) of the diffraction peak. Insights from the experimental data presented in this work can establish proper measurement protocols to enable accurate and rapid residual stress analysis using portable 2DXRD instruments and improve the current practice of quality control in surface treatment industry. [ABSTRACT FROM AUTHOR]

The Polarimetric Synthetic Aperture Radar (PolSAR) systems use electromagnetic radiations of different polarizations in the microwave frequency to collect the scattering information from targets on the Earth. Nevertheless, as with any other electronic device, the PolSAR systems are also not ideal and subjected to distortions. The most important of these distortions are the polarimetric distortions caused due to the channel imbalance, phase bias, and crosstalk between the different polarization channels. For the spaceborne PolSAR systems, the Earth's ionosphere also contributes to an additional polarimetric distortion known as the Faraday rotation. An effort was made in this study to perform the polarimetric calibration of the Quad-pol and Compact-pol PolSAR datasets acquired using different airborne and spaceborne PolSAR systems to estimate and minimize these polarimetric distortions. The investigation was also done to analyze the impact of these polarimetric distortions on the scattering mechanisms from ground targets and on its dependency on the radar wavelength. The study was done using the UAVSAR L-band Quad-pol dataset, RADARSAT-2 Quad-pol dataset, ALOS-2 PALSAR-2, ISRO's L&S- Band Airborne SAR (LS-ASAR) Quad-pol and Compact-pol datasets, and the RISAT-1 Compact-pol dataset. Calibration of the airborne PolSAR data was carried to understand the level of polarimetric distortions in the LS-ASAR product that is a precursor mission to the spaceborne Dual-Frequency L&S Band NASA-ISRO Synthetic Aperture Radar (NISAR) mission. It is understood that the crosstalk is the dominant polarimetric distortion, which severely affects the PolSAR datasets compared to the other polarimetric distortions, and it is more for the higher wavelength PolSAR systems. The Quegan, Improved Quegan, and Ainsworth algorithms for crosstalk estimation and minimization was performed for the different Quad-pol datasets and it was found that the Improved Quegan algorithm is suitable for removing crosstalk from datasets having high crosstalk and the Ainsworth algorithm is suitable for removing crosstalk from datasets having low crosstalk. The Freeman method of the polarimetric calibration was implemented for the compact-pol datasets and it was able to considerably minimize the polarimetric distortions. The coherency matrix, scattering matrix, model-based decomposition, polarimetric signatures, and roll invariant parameter-based analysis revealed that all the datasets after polarimetric calibration were showing the correct scattering responses expected from the ground targets. [ABSTRACT FROM AUTHOR]

While the influence of surface melt on Antarctic ice shelf stability can be large, the duration and affected area of melt events are often small. Therefore, melt events are difficult to capture with remote sensing, as satellite sensors always face the trade-off between spatial and temporal resolution. To overcome this limitation, we developed UMelt: a surface melt record for all Antarctic ice shelves with a high spatial (500 m) and high temporal (12 h) resolution for the period 2016–2021. Our approach is based on a deep learning model, specifically a U-Net, which was developed in Google Earth Engine. The U-Net combines microwave remote sensing observations from three sources: Sentinel-1, Special Sensor Microwave Imager/Sounder (SSMIS), and Advanced Scatterometer (ASCAT). The U-Net was trained on the Shackleton Ice Shelf for melt seasons 2017–2021, using the fine-scale melt patterns of Sentinel-1 as reference data and SSMIS, ASCAT, a digital elevation model, and multi-year Sentinel-1 melt fraction as predictors. The trained U-Net performed well on the Shackelton Ice Shelf for test melt season 2016–2017 (accuracy: 91.3%; F1-score: 86.9%), and the Larsen C Ice Shelf, which was not considered during training (accuracy: 91.0%; F1-score: 89.3%). Using the trained U-Net model, we have successfully developed the UMelt record. UMelt allows Antarctic-wide surface melt to be detected at a small scale while preserving a high temporal resolution, which could lead to new insights into the response of ice shelves to a changing atmospheric forcing. • Satellite resolution trade-offs hamper accurate surface melt detection in Antarctica. • We present UMelt: An Antarctic-wide, high-resolution surface melt record. • UMelt was developed by merging multi-source remote sensing data using deep learning. • UMelt detects intricate surface melt events that were difficult to capture before. [ABSTRACT FROM AUTHOR]

Although lack-of-fusion porosity due to incomplete melting of powder can limit the mechanical properties of additively manufactured metals, quantification and prediction of these defects remains challenging. We compare three common strategies to measure porosity: the Archimedes, micrograph-based, and micro-computed tomography approaches. We find that while these methods work equally well at low void fraction, their predictions diverge at higher void fractions (> 5 %). We find that the disparity comes since the Archimedes method measures the total amount of solid in the sample, while micrograph-based approach neglects loose powder trapped inside the samples that can be removed during the preparation process. We conclude that these two methods make use of divergent definitions of porosity. While the Archimedes method measures a "total porosity" defined by the total volume fraction of void in the material, the micrograph method measures an "effective porosity" that only accounts for the continuous material. On the other hand, the resolution of micro-computed tomography is limited by voxel size, leading to ambiguity of trapped powder being identified as solid or void. Consequently, the number density of defects from micro-computed tomography are noticeably smaller than that from micrograph-based approach. A geometric model for porosity prediction is implemented and used to evaluate different models for melt pool geometry. Our numerical predictions of melt pool profiles are surprisingly insensitive to our choice of heat source models. Finally, an analytical geometric model is developed for fast estimation of total and effective porosities and shows good agreement with both numerical simulations and experimental measurement. [ABSTRACT FROM AUTHOR]

This manuscript identifies and documents unsolved problems and research challenges in the extended reality (XR) domain (i.e., virtual (VR), augmented (AR), and mixed reality (MR)). The manuscript is structured to include technology, design, and human factor perspectives. The text is visualization/display-focused, that is, other modalities such as audio, haptic, smell, and touch, while important for XR, are beyond the scope of this paper. We further narrow our focus to mainly geospatial research, with necessary deviations to other domains where these technologies are widely researched. The main objective of the study is to provide an overview of broader research challenges and directions in XR, especially in spatial sciences. Aside from the research challenges identified based on a comprehensive literature review, we provide case studies with original results from our own studies in each section as examples to demonstrate the relevance of the challenges in the current research. We believe that this paper will be of relevance to anyone who has scientific interest in extended reality, and/or uses these systems in their research. [ABSTRACT FROM AUTHOR]