bluuebunny/crossref_metadata_2025_split huggingface dataset:
A review on optical bandgap engineering in TiO2nanostructures via doping and intrinsic vacancy modulation towards visible light applications
Authors: Nair Radhika V , Gummaluri Venkata Siva , Matham Murukeshan Vadakke , C Vijayan 
Published: March 2022

AbstractThe prospect of engineering the bandgap in semiconductor nanostructures all the way from ultraviolet to visible is highly significant in various applications such as photocatalysis, sensing, optoelectronics and biomedical applications. Since many semiconductors have their bandgaps in the UV region, various techniques are used to tune their bandgaps to the visible region. Doping and co-doping with metals and non-metals have been found to be highly effective in bandgap narrowing as doping creates a continuum of mid-bandgap states which effectively reduces the bandgap. Other than these techniques, the modulation of intrinsic vacancies is an effective way to control the bandgap. Among all semiconductors, titanium dioxide (TiO2) is a well-studied material for UV photocatalytic applications. TiO2has oxygen and titanium vacancies as intrinsic defects which influence the bandgap based on its phase of existence. The oxygen vacancies generate unpaired electrons associated with Ti3+species, resulting in the creation of donor levels within the bandgap. Trivacancies give a p-type nature to TiO2due to excess holes and generate acceptor levels in the bandgap. The existence of a continuum of such intrinsic defect states within the bandgap appears to narrow the bandgap and enhances the visible light absorption in TiO2, although the effect is an apparent narrowing. Doping and co-doping of TiO2with metals such as Au, Ag, Fe, Co, Ni, Pt and Pd and non-metals such as B, C, N, Br and Cl, doping with Ti3+ions and hydrogenation have all been found to narrow the bandgap of TiO2. In this review, we focus on such intrinsic vacancy-modulated bandgap narrowing in TiO2. This review covers significant recent advancements in bandgap engineering of TiO2.
Tuning the adiabaticity of spin dynamics in diamond nitrogen vacancy centers
Authors: Band Y B , Japha Y 
Published: March 2022

Abstract
We study the spin dynamics of diamond nitrogen vacancy (NV) centers in an oscillating magnetic field along the symmetry axis of the NV in the presence of transverse magnetic fields. It is well-known that the coupling between the otherwise degenerate Zeeman levels |M

S
= ±1⟩ due to strain and electric fields is responsible for a Landau–Zener process near the pseudo-crossing of the adiabatic energy levels when the axial component of the oscillating magnetic field changes sign. We derive an effective two-level Hamiltonian for the NV system that includes coupling between the two levels via virtual transitions into the third far-detuned level |M

S
= 0⟩ induced by transverse magnetic fields. This coupling adds to the coupling due to strain and electric fields, with a phase that depends on the direction of the transverse field in the plane perpendicular to the NV axis. Hence, the total coupling of the Zeeman levels can be tuned to control the adiabaticity of spin dynamics by fully or partially compensating the effect of the strain and electric fields, or by enhancing it. Moreover, by varying the strength and direction of the transverse magnetic fields, one can determine the strength and direction of the local strain and electric fields at the position of the NV center, and even the external stress and electric field. The nuclear spin hyperfine interaction is shown to introduce a nuclear spin dependent offset of the axial magnetic field for which the pseudo-crossing occurs, while the adiabaticity remains unaffected by the nuclear spin. If the NV center is coupled to the environment, modeled by a bath with a Gaussian white noise spectrum, as appropriate for NVs near the diamond surface, then the spin dynamics is accompanied by relaxation of the Zeeman level populations and decoherence with a non-monotonic decrease of the purity of the system. The results presented here have important impact for metrology with NV centers, quantum control of spin systems in solids and coupled dynamics of spin and rotations in levitated nano-objects in the presence of magnetic fields.
On the length used for CT ionization chambers to determine CTDI
Authors: DeWerd Larry A , Khan Ahtesham Ullah , Jensen Andrew R 
Published: March 2022

Abstract

Objective. Computed tomography dose index (CTDI) calculations based on measurements made with CT ionization chambers require characterization of two chamber properties: radiation sensitivity and effective length. The sensitivity of a CT ionization chamber is currently determined in some countries by calibration in an x-ray field that irradiates the entire chamber. Determination of the effective length is left to the user, and this value is frequently assumed to be equivalent to the nominal length—typically 100 mm—stated by the manufacturer. This assumption undermines the intention and usefulness of CTDI calculation. Thus, a slit-based calibration, N
KL, of the CT ionization chambers was proposed by collimating the x-ray beam to a well-defined aperture width. The aim of this work is to compare the two methods. Approach. Four different CT ionization chambers (Standard Imaging Exradin A101, Radcal 10x5-3CT, Victoreen 500-100, and Capintec PC-4P) are investigated in this work. Sensitivity profiles were measured for all four chambers and effective/rated chamber lengths were calculated. A novel Monte-Carlo based correction was proposed to account for the presence of the aperture. CTDI was calculated and compared for two calibration beams as well as for a commercial CT scanner using Exradin A101 and Radcal 10x5-3CT chambers. Main results. The nominal chamber length was found to deviate up to 21% compared to the effective length. Correction for the aperture depended on the aperture opening size. CTDI calculation results illustrate the potential 17% error in CTDI calculation that can be caused by assuming the effective chamber length is equivalent to the manufacturer’s stated nominal length. CTDI calculations with CT ionization chambers calibrated with an air-kerma length calibration method yield the smallest variation in the CTDI regardless of the chamber model. Significance. To avoid an erroneous CTDI, information regarding the chamber’s effective length must be included in the calibration or stated by the manufacturer. Alternatively, a slit-based calibration can be performed.
Schottky contact diameter effect on the electrical properties and interface states of Ti/Au/p-AlGaAs/GaAs/Au/Ni/Au Be-doped p-type MBE Schottky diodes
Authors: Lakhdari Issam , Sengouga Nouredine , Labed Madani , Tibermacine Toufik , Mari Riaz , Henini Mohamed 
Published: March 2022

Abstract
Schottky diodes based on Be-doped p-type AlGaAs were grown by molecular beam epitaxy and their current–voltage (I–V) and capacitance–voltage (C–V) characteristics measured. The Schottky and Ohmic contacts are Ti/Au and Au/Ni/Au, respectively. The effect of the Schottky contact diameter on I–V and C–V characteristics was studied. To elucidate this effect, the Schottky diode figures of merits and interface states are extracted from I–V and C–V characteristics, respectively. It was found that interface states density increases with increasing Schottky contact diameter then saturates beyond 400 µm. The frequency dependence of the C–V characteristics was also related to these interface states. The results of this present study can help choosing the right Schottky contact dimensions.
4D printed shape memory sandwich structures: experimental analysis and numerical modeling
Authors: Serjouei A , Yousefi A , Jenaki A , Bodaghi M , Mehrpouya M 
Published: March 2022

Abstract
Additive manufacturing has provided a unique opportunity to fabricate highly complex structures as well as sandwich structures with various out-of-plane cores. The application of intelligent materials, such as shape memory polymers, gives an additional dimension to the three-dimensional (3D) printing process, known as four-dimensional (4D) printing, so that the deformed structures can return to their initial shape by the influence of an external stimulus like temperature. In this study, 4D printing of smart sandwich structures with the potential of energy absorption is investigated. The samples were fabricated considering various process parameters (i.e. layer height, nozzle temperature, printing velocity, and wall thickness) and tested mechanically. The experimental work reveals that the deformed sandwiches can fully recover their initial form by applying simple heating. Besides, a reliable finite element model (FEM) was developed to predict the functional behavior of the horseshoe sandwich structures in compression analysis. The experimental and simulation results show that among process parameters, wall thickness, layer height, and nozzle temperature are the most significant parameters to increase the compressive load and, consequently, the energy absorption rate. The concept, results, and modeling provided in this study are expected to be used in the design and fabrication of 4D printed sandwich structures for energy absorption applications.
Resonance-like enhancement of forced nonlinear diffusion as a nonequilibrium phase transition
Authors: Goychuk Igor 
Published: March 2022

Abstract
We describe the phenomenon of a resonance-like, giant enhancement of diffusion in a basic model of nonlinear diffusion featured by a nonlinear in velocity friction and the corresponding multiplicative thermal noise. The model is consistent with thermal equilibrium in the absence of driving. Different from previous studies of this phenomenon, where the crucial nonlinearity originates from a periodic external potential while friction is linear, we focus on the case of a constant force driving, whereas the crucial nonlinearity stems from the friction. The basic model of such friction considered interpolates between linear viscous Stokes friction at small velocities and dry Coulomb-like friction at large velocities corresponding to a stress plateau in some nonlinear viscoelastic materials. Recently, a nonequilibrium phase transition to super-diffusion and super-transport was discovered within this basic model. We show that adding a tiny viscous friction part to major nonlinear friction regularizes in part this behavior. Diffusion becomes asymptotically normal. However, the phase transition translates into a giant enhancement of normal diffusion and mobility of particles at the transition point over the intuitively expected large force limit, where the linearization of friction occurs. Such a giant enhancement of diffusion is closely related to the largely enhanced kinetic temperature of the particles at and beyond the critical point. We provide analytical results obtained within an effective mass approximation which nicely agree with stochastic numerics.
Jackiw-Teitelboim and Kantowski-Sachs quantum cosmology
Authors: Fanaras Georgios , Vilenkin Alexander 
Published: March 2022

Abstract
We study quantum cosmology of the 2D Jackiw-Teitelboim (JT) gravity with Λ > 0 and calculate the Hartle-Hawking (HH) wave function for this model in the minisuperspace framework. Our approach is guided by the observation that the JT dynamics can be mapped exactly onto that of the Kantowski-Sachs (KS) model describing a homogeneous universe with spatial sections of S
1 × S
2 topology. This allows us to establish a JT-KS correspondence between the wave functions of the models.
We obtain the semiclassical Hartle-Hawking wave function by evaluating the path integral with appropriate boundary conditions and employing the methods of Picard-Lefschetz theory. The JT-KS connection formulas allow us to translate this result to JT gravity, define the HH wave function and obtain a probability distribution for the dilaton field.
Model for access and stability of the X-point radiator and the threshold for marfes in tokamak plasmas
Authors: Stroth U. , Bernert M. , Brida D. , Cavedon M. , Dux R. , Huett E. , Lunt T. , Pan O. , Wischmeier M. , ASDEX Upgrade Team the 
Published: March 2022

AbstractBased on particle and energy balances, a reduced model is derived for the physical mechanisms leading to the occurrence of stable and unstable X-point radiators (XPRs), the latter also known as marfes. The leading roles of the neutral deuterium density in the divertor region for initiating XPRs is highlighted. An access condition is formulated whose parameter dependencies are consistent with experimental observations and which could also apply to the process of divertor detachment. With an exponential increase of the recombination rate at low temperature, the XPR becomes magnetohydrodynamically unstable, leading to a marfe and, possibly, to a disruption. A critical density for marfe occurrence is formulated with the upstream density and safety factor as leading parameters, as in the experiment. Marfes are predicted to be more likely in carbon devices than in impurity-seeded plasmas in tungsten devices. The edge plasma parameter domain where marfes occur resembles that used for active marfe avoidance schemes. Both the XPR and marfe occurrence parameter can be used to guide active discharge control.
Thin film sensing in a planar terahertz meta-waveguide
Authors: Islam Maidul , Kumar Bhowmik Bhairov , Dhriti K M , Minakshi  , Mohan Devendra , Ahmad Amir , Kumar Gagan 
Published: March 2022

Abstract
In this paper, we explore the sensing characteristics of a terahertz meta-waveguide consisting of a one-dimensional array of periodically arranged sub-wavelength scale split-ring resonators (SRRs). The substrate of the meta-waveguide structure has two layers. The lower one is made of metal, whereas the upper layer is made of a dielectric. On top of it, metallic SRRs are placed. The meta-waveguide is capable of guiding the fundamental as well as the higher-order terahertz modes along the designed structures. We analyze the sensing capability of the meta-waveguide by covering it with a thin film analyte. The waveguide transmission properties are observed for varying refractive indices of the analyte. Different sensing parameters such as frequency shift, sensitivity, and figure of merit (FoM) of resonance modes supported by the meta-waveguide have been studied. The obtained values of sensitivity and FoM indicate a better sensing capability of the meta-waveguide rather than metamaterial-based structures in the transmission approach. We also employ a coupled harmonic oscillator model in order to interpret and validate the numerical observations. The meta-waveguide design can open alternate avenues for sensing thin film analytes with greater sensitivity.
Improving surface characteristics and corrosion resistance of medical grade 316L by titanium powder mixed electro-discharge treatment
Authors: Singh Gurpreet , Singh Malkeet , Singh Sidhu Sarabjeet , Ablyaz Timur Rizovich 
Published: March 2022

Abstract
The article focuses on the corrosion behavior of medical grade 316L stainless steel used in cardiac stents, orthopaedic, and dental implants. In this research work, electro-discharge treatment (EDT) was used for the deposition of titanium dioxide (TiO2) particles on 316L stainless steel to improve its corrosion-resistant property. The samples were characterized using scanning electron microscopy and x-ray diffraction techniques to correlate the modified surface with the EDT process parameters. The electrochemical corrosion analysis shows a lower corrosion rate for the TiO2 coated specimen (1.883 mpy) compared to the untreated surface (13.729 mpy). This improved corrosion resistance of TiO2 coated substrate was attributed to the formation of various silicides, carbides, and bioactive compounds.
Research on prediction of WMA mixing temperature or additive dosage using digital image recognition of coating rate
Authors: Wang Liming , Kang Jinling , Fan Yibing , Ma Kun , Gong Chun 
Published: March 2022

Abstract
It is difficult to determine a reasonable mixing temperature for WMA based solely on the viscosity-temperature relationship of the binder, as is the case for HMA, and it is a more reasonable solution to determine the mixing temperature of WMA by the state of the mix. This paper proposes to use the coating rate as an index for determining the mixing temperature of WMA, to analyze the reliability and sensitivity of this index using a digital image recognition method, and to analyze the influence law of this method based on the coating rate recognition test. The study shows that: The precision of the digital image coating rate recognition test can meet the requirements of calculating the mixing temperature; in a certain range, the coating rate of WMA is positively correlated with the mixing temperature or additive dosage; the sensitive variation of the coating rate with mixing temperature and additive dosage can be used to predict the engineering mixing temperature or additive dosage for WMA; the slope of the coating rate contour also has some common trends and can be used to illustrate the effect of warm mix additives (or warm mix technology) on the effectiveness or efficiency of warm mix.
Soft memtransistor with ion transfer interface
Authors: Zhang Zhong-Da , Zhong Ya-Nan , Xu Jian-Long , Gao Xu , Wang Sui-Dong 
Published: March 2022

Abstract
A paradigm for soft memtransistor is demonstrated based on the ion transfer interface, consisting of an ion-rich semiconducting polymer layer on the top and a gelatin dielectric for receiving ions on the bottom. The flexible polymer memtransistor acted as an analog-type memristor without gating, and its memristive strength could be largely modulated by applying gate voltage. It is proposed that the ion redistribution across the ion transfer interface can modify the hole doping level in the polymer layer, which is responsible for the tunable memristive characteristics. Different levels of synaptic potentiation and depression were successfully emulated using the polymer memtransistor, and it is promising to extend the emulation to multi-terminal heterosynaptic plasticity.
Saying goodbye? Downsizing—are human resources assets or liabilities?
Authors: Wilkinson Adrian 
Published: March 2022

Abstract
‘Saying goodbye? Downsizing—are human resources assets or liabilities?’ addresses the topic of downsizing, which is a fact of business life and of Human Resource Management (HRM). There are three main approaches to downsizing: workforce reduction, work redesign, and systemic. Many organizations—whether in the public or private sectors across the European, Australasian, and US economies—have a preoccupation with cost-cutting, so seek to reduce staff numbers on a yearly basis. However, there is a concern that the cost-cutting regime associated with many organizational change strategies has fractured the traditional employment relationships. Ultimately, the impact of downsizing on the organization and staff is very much affected by the way it is implemented.
Sensitivity analysis and methodological choices on health-related impoverishment estimates in Cambodia, 2009–17
Authors: Fernandes Antunes Adélio , Jacobs Bart , Jithitikulchai Theepakorn , Nagpal Somil , Tong Kimsun , Flessa Steffen 
Published: March 2022

Abstract
The measurement of health expenditure–related impoverishment as a proxy of financial risk protection is regularly used as an indicator of progress towards universal health coverage. However, the use of this indicator is greatly sensitive to analysts’ choices and data sources, making comparisons across time and countries challenging. We report the results of a sensitivity analysis of critical methodological choices in estimating health-related financial impoverishment in Cambodia from 2009 to 2017. We include the following in our analysis: the construction and data sources for consumption aggregates and out-of-pocket health estimates; the use of international and national absolute and relative poverty thresholds (defined by the share of household food consumption); time and regional price adjustment methods and index sources. Marginal changes substantially affected estimates at the national and regional levels among households. In most cases, the choice of poverty thresholds and temporal and regional deflators had a significant effect. An increase of 0.01 USD in the average daily per capita poverty line resulted in relative increases in impoverished incidences of 2.90–2.62% for 2009 and 3.06–2.95% for 2014. From 2013 onwards, estimates for impoverishment in rural areas based on median food consumption were often significantly higher than estimates using official poverty lines. The high sensitivity of the impoverishment indicator cautions against its use in assessing health-related financial hardship and protection, especially with low and absolute poverty lines. In the context of low- and middle-income countries, assessing financial hardship in relative terms by using measures such as catastrophic health expenditure, complemented with research on coping strategies and their socio-economic effects on households, may be more conducive to policymaking goals and progress towards achieving universal health coverage.
Psychological Factors Associated With Adherence to Oral Treatment in Ulcerative Colitis
Authors: Dasharathy Sonya S , Long Millie D , Lackner Jeffrey M , Ben-Ami Shor Dana , Yang Liu , Bar Nir , Ha Christina , Weiss Guy A 
Published: March 2022

Abstract

Introduction
Medication nonadherence in patients with ulcerative colitis (UC) can result in frequent relapses, severe disease, and higher risk of colorectal cancer. Behavioral models relying on motivation and perceived competence, like the self-determination theory (SDT), have been implicated in nonadherence; however, the SDT has not been evaluated in the adult UC population. We sought to examine the association between adherence to oral medications in patients with UC and psychological distress, relationship with health care providers, motivation, and competence.

Methods
We performed a cross-sectional study within the Inflammatory Bowel Disease (IBD) Partners online registry in which participants completed a baseline survey including demographic information, IBD history, symptoms, medication adherence, and psychosocial factors. Members of the registry with a diagnosis of UC received an online follow-up survey that included baseline questionnaires and assessment of competence, motivation, and patient-physician relationship. Logistic regression models were performed to determine the relationship between psychosocial factors, adherence modifiers, and medication adherence.

Results
Of the 410 UC patients included, 29% had low adherence to their medications, 36% had medium adherence, and 34% had high adherence. In the multivariable analysis, younger patients, those with a lower perceived competence, and those with worse relationship with their providers were more likely to have lower adherence to their medications.

Conclusions
Poor adherence to oral medications in UC was associated with lower perceived competence and worse relationship with providers. Further interventions based on the SDT can potentially improve adherence and optimize patient care.