bluuebunny/crossref_metadata_2025 huggingface dataset:
Prognostication in Poststroke Aphasia: Perspectives of Significant Others of People With Aphasia on Receiving Information About Recovery
Authors: Cheng Bonnie B. Y. , Ryan Brooke J. , Copland David A. , Wallace Sarah J.
Published: January 2022

Purpose:

Knowing what to expect poststroke is important for many significant others of people with aphasia, yet an understanding of their perceptions and preferences in receiving prognostic information is limited. This knowledge is needed to inform the formulation and delivery of aphasia prognoses as conversations about prognosis can be harmful or helpful depending on their alignment with key stakeholder perspectives. Our preliminary study sought insight into the perspectives of significant others of people with aphasia on receiving prognostic information, with an aim toward informing evidence-based practice in aphasia prognostication.

Method:

We interviewed seven significant others of people with aphasia, 3–12 months poststroke. The interviews were semistructured, conducted one-to-one, and analyzed qualitatively using reflexive thematic analysis.

Results:

Five themes were drawn from the interviews: (a) You don't know what you don't know. (b) Having them alive is the best you can ask for. (c) Recovery in the eye of the beholder. (d) Outcomes don't matter unless they help me help them. (e) It's my prognosis too if I'm living with aphasia.

Conclusions:

A significant other's prognosis-related perceptions and preferences are products of their poststroke reality and may inadvertently shape that of the person with aphasia. In order to facilitate recovery, prognostication practices need to consider the needs of significant others both as providers of care and as requiring care themselves for their first-hand experiences of third-party disability.
Moving Beyond Single Word Acquisition of Speech Sounds to Connected Speech Development With Dynamic Assessment
Authors: Glaspey Amy M. , Wilson Jenica J. , Reeder Justin D. , Tseng Wei-Chen , MacLeod Andrea A. N.
Published: January 2022

Purpose:

The aim of this study was to document speech sound development across early childhood from a dynamic assessment (DA) perspective that captures a breadth of linguistic environments using the Glaspey Dynamic Assessment of Phonology (Glaspey, 2019), as well as to provide normative data for speech-language pathologists to compare speech skills when making clinical decisions and provide historical context. Targets of English were evaluated via DA for the (a) age of acquisition in single words; (b) continued development through connected speech; (c) early, mid, and late sequence; and (d) differences between single word and connected speech productions.

Method:

Data were extracted from the reported results of the norming study for the Glaspey Dynamic Assessment of Phonology, which included a representative sample of 880 children ages 3 years to 10;11 (years;months). Comparisons were made with 49 items including multisyllabic words, clusters, and phonemes of English across word positions.

Results:

Assessment with DA showed that acquisition in single words is nearly complete by age 6 years with a 90% mastery level, and the sequence suggests an Early-13, Mid-16, and Late-14 for items by word position. In connected speech, a wider range of progression is evident from the emergence of sound production at 50%, 75%, and 90% mastery levels with observed changes between ages 3 and 10 years.

Conclusions:

Given a DA approach across connected linguistic environments, children continue to progress in their development of speech sounds from early childhood well into their school-age years and for some sounds beyond the age of 10 years. DA challenges the language system to better reflect children's developmental progression.
The impact of cosmic-ray attenuation on the carbon cycle emission in molecular clouds
Authors: Gaches Brandt A. L. , Bisbas Thomas G. , Bialy Shmuel
Published: January 2022

Context. Observations of the emission of the carbon cycle species (C, C+, CO) are commonly used to diagnose gas properties in the interstellar medium, but they are significantly sensitive to the cosmic-ray ionization rate. The carbon-cycle chemistry is known to be quite sensitive to the cosmic-ray ionization rate, ζ, controlled by the flux of low-energy cosmic rays which get attenuated through molecular clouds. However, astrochemical models commonly assume a constant cosmic-ray ionization rate in the clouds.

Aims. We investigate the effect of cosmic-ray attenuation on the emission of carbon cycle species from molecular clouds, in particular the [CII] 158 μm, [CI] 609 μm, and CO (J = 1–0) 115.27 GHz lines.

Methods. We used a post-processed chemical model of diffuse and dense simulated molecular clouds and quantified the variation in both column densities and velocity-integrated line emission of the carbon cycle with different cosmic-ray ionization rate models.

Results. We find that the abundances and column densities of carbon cycle species are significantly impacted by the chosen cosmic-ray ionization rate model: no single constant ionization rate can reproduce the abundances modeled with an attenuated cosmic-ray model. Further, we show that constant ionization rate models fail to simultaneously reproduce the integrated emission of the lines we consider, and their deviations from a physically derived cosmic-ray attenuation model is too complex to be simply corrected. We demonstrate that the two clouds we modeled exhibit a similar average AV,eff – nH relationship, resulting in an average relation between the cosmic-ray ionization rate and density ζ(nH).

Conclusions. We conclude by providing a number of implementation recommendations for cosmic rays in astrochemical models, but emphasize the necessity for column-dependent cosmic-ray ionization rate prescriptions.
Recycling of ashes from thermal stations for the production of an ecological mortar: New application in civil engineering
Authors: Mghaiouini Redouane , Abdelhadi Mortadi , Saifaoui Dennoun , Salah Mohammed , Graich Abderrazzak , Chahid El ghaouti , Taoufik Garmim , Abderrahmane Elmlouky , Mrani Brahim , Ghanim Hassan , Monkade Mohamed , ElBouari Abdeslam
Published: January 2022

The main idea of this work is to investigate about the flexural and compressive forces of the mortar, which was developed from fly ash, hearth ash, and magnetized water with different times of magnetization. The results of this work reveal that the flexural and compressive force of mortars realized with magnetized water is higher than those prepared with non magnitezed water. The best result of increasing the flexural and the compressive forces of the mortar are obtained when the water magnetization time is equal to 20 min. The growth in flexural and the compressive forces of the mortar elaborated with magnetized water is proportional to the magnetization time.
Experimental Study on Mechanism of Water-Alternating-Gas Injection in thick Sandstone Reservoir
Authors: Li Xiaofei , Li Aifen , Guo Wanjiang , Liu Shiqi , Cui Shiti
Published: January 2022

For the thick sandstone reservoir, due to gravity differentiation, water drive mainly uses the bottom oil of the reservoir, while gas drive mainly drives the oil along the top of the reservoir. Water-alternating gas (WAG) injection can effectively combine the advantages of water flooding and gas injection, so that gas and water can work in synergy, thus further expanding swept volume and enhancing oil recovery. Over the past half century, the technology has been successfully applied to more than 60 oilfields worldwide, but its mechanism remains to be further studied. In this paper, a total of three tests were conducted through conventional water-flooding (WF), water flooding followed by gas flooding and WAG in sand-packed 2d-model. These experimental processes are recorded by video with time so that the saturation distribution of each phase in porous media can be observed，migration law of gas and water is studied, and the mechanism of WAG displacement is analyzed. The results show that gravity and capillary force have great influence on the process of gas water alternation, thus increasing the overall swept volume of water and gas; The water/gas alternating injection has the highest oil recovery factor (RF) of 75.45% in test 3, in comparison with water flooding followed by gas flooding (70.85% in test 2) and water-flooding (66.7%in test 1); Increase in cycles of WAG tends to reduce residual oil saturation.
Research status of different improvement measures for saline-alkali land
Authors: Li Jian
Published: January 2022

Cultivated land is the fundamental guarantee of food security, and saline-alkali land affects the quality of cultivated land to varying degrees. It is of great significance to study saline-alkali land improvement measures to solve the problem of saline-alkali land utilization, promote the healthy development of agriculture and animal husbandry, and improve the quality of cultivated land. The author has sorted out the relevant literature and reports on the improvement methods and technologies of saline-alkali land at home and abroad in recent years, and introduced the status and effects of different improvement measures for saline-alkali land from four types: chemical improvement measures, physical improvement measures, water conservancy improvement technology and biological improvement measures. It provides a theoretical basis for the study of governance and saline-alkali land improvement measures.
Decarburisation of Fe-C alloy strips by gas–solid reaction in Ar-CO-CO2
Authors: Zhou Meijie , Ai Liqun , Hong Lukuo , Sun Caijiao , Zhou Yuqing , Meng Fanjun
Published: January 2022

The gas–solid reaction decarburisation of cast iron strips is a direct steel production method with low production costs. In this study, the decarburisation kinetics of Fe-C alloy strips in an Ar-CO-CO2 atmosphere were investigated. Fe-C alloy strips with 4.2 wt.% C and different thicknesses (1, 1.5, and 2 mm) were used for the decarburisation experiments under temperatures of 1293, 1353, and 1413 K. The results indicate that, under appropriate mixed gas conditions, rapid decarburisation can be achieved. With an increase in the decarburisation temperature, the decarburisation rate increases significantly. Under the same decarburisation temperature and time, thinner Fe-C alloy strips exhibit a better decarburisation effect. The decarburisation process includes three rate-limiting stages, namely gas and surface reaction, carbon diffusion, and cementite decomposition. The microstructure of the decarburised strips comprises a complete decarburised layer and a partial decarburised layer, and the thickness of the complete decarburised layer increases with decarburisation time. The decarburisation of the Fe-C alloy strip is an apparent first-order reaction with an activation energy of 124.7 kJ ∙ mol−1, and the activation energy for the growth of the complete decarburised layer is 132.3 kJ ∙ mol−1. The results of this study can help develop more efficient and cost-effective steel production methods.
Hymenal Tag in a Newborn
Authors: Arredondo Montero Javier , Anaut Mónica Bronte , Antona Giuseppa , Pascual Carlos Bardají
Published: January 2022

Case presentation

We report on a 7-day-old female newborn at
term, with no associated pathology, in
whom a smooth pinkish formation was observed
in the dorsal part of the hymen, protruding
between the labia minora Fig. 1.
Physical examination suggested a hymenal
tag, a polypoid hymenal lesion secondary
to maternal estrogen exposure that tends
to resolve spontaneously in the first months
of life, and thus excluded the initial need for
complementary tests. As expected, the excrescence
progressively disappeared during
the first months of life Fig. 2.
DABSO – A Reagent to Revolutionize Organosulfur Chemistry
Authors: Willis Michael C. , Andrews Jonathan A.
Published: January 2022

The introduction of easy-to-handle SO2 surrogates has transformed the field of sulfur chemistry, enabling methodologies utilizing SO2 to be carried out without specialized apparatus, and paving the way for the development of new procedures. This review highlights some of the varied and significant developments associated with one of the most prominent SO2 surrogates: DABSO.

1 Introduction

2 DABSO

3 Reactions with Nucleophilic Reagents

4 Metal-Catalyzed Reactions

4.1 Palladium-Catalyzed Reactions

4.2 Other Transition-Metal Catalysis

5 Radical Reactions

5.1 Aryldiazonium Salts

5.2 Other Aryl Radical Precursors

5.3 Alkyl Radical Precursors

6 Conclusion
Free-surface effects induced by internal solitons forced by shearing currents
Authors: la Forgia Giovanni , Sciortino Giampiero
Published: January 2022

Free-surface effects induced by internal solitary waves (ISWs) propagating through a background shear current are theoretically investigated in a shallow water framework. Following the Hamiltonian approach, we implement a mathematical formulation valid for a free surface, two-layer stratified system in the presence of mobile layers. Associated to the undisturbed condition characterized by the background fluid at rest, solitons with both positive and negative polarities are considered. To reproduce the typical oceanic conditions, we focus on theoretical predictions for a density ratio set to 0.99. Although under Boussinesq conditions a rigid-lid at the top of the theoretical domain is considered a good approximation, our analysis shows that main ISWs features may change when the fluid system, forced by shear currents, is modeled with a free surface. Signs assumed by three dimensionless quantities, i.e., the deformation parameter, the background velocity, and the undisturbed amplitude, allowed us to uniquely predict how the undisturbed solitons modify their interfacial profiles and change their celerity, in response to the background forcing. Our results show that waves celerity predicted by the rigid-lid model can be lower than the one resulting from the Hamiltonian formulation, although this never occurs in the absence of mobile layers. Theoretical predictions reveal that shearing current can induce deviations from the standard ISWs free-surface profile. We discuss the role of nonhydrostatic pressures in inducing free-surface short disturbances, in the form of undulated or multihumped profiles. The typical phase-opposition between interfacial and surface displacements can be lost as the free-surface displacements assume multihumped configurations.
Parametric study about performances of a solar photovoltaic/thermal hybrid using a spectral beam splitting technique
Authors: Liew Nicholas J. Y. , Yu Zhengshan (Jason) , Holman Zachary , Lee Hyun-Jin
Published: January 2022

This study presents performance variations of a solar photovoltaic/thermal (PV/T) hybrid using spectral beam splitting (SBS) techniques. Compared with conventional solar PV/T hybrids (the one-sun flat-plate PV/T hybrid), the proposed hybrid simultaneously produces electricity and relatively higher grades of thermal energy. The majority of the studies related to SBS solar PV/T hybrids are in the early stages of design or proof-of-concept. Therefore, the proposed hybrid's operating characteristics must be investigated. This study provides comprehensive information about the influence of the main operating parameters on the proposed hybrid system's performance. The main operating parameters considered in this parametric study are solar irradiance, ambient temperature, thermal fluid mass flow rate, and inlet fluid temperature. While these parameters were well known to affect most solar technologies' performance, few studies have reported the extent of their impact on SBS solar PV/T hybrids. The results show that the ambient temperature is the greatest influence on the hybrid efficiency. When the ambient temperature increases from 0 °C to 40 °C, the hybrid efficiency decreases from 71.5% (the highest) to 63.7%. The overall efficiency of the hybrid was strongly dependent on the hybrid's PV component. As compared with the hybrid's parabolic trough collector (PTC) component, the PV performance was highly influenced by operating conditions. Nonetheless, compared with the original system design (pure PTC and pure PV), these operating parameters have relatively low impact on both PTC and PV in the hybrid system.
Experimental investigations of hard x-ray source produced by picosecond laser-irradiated solid target
Authors: Li Meng-ting , An Hong-hai , Hu Guang-yue , Xiong Jun , Lei An-le , Xie Zhi-yong , Wang Chen , Wang Wei , Zhang Zhen-chi , Huang Lin-gen
Published: January 2022

Measurements of Kα line and bremsstrahlung continuous x-ray emission from high-intensity laser-irradiated thin targets are presented. The experiments were performed at the SG-II UP Petawatt laser. Self-standing Sn foils varying thicknesses and Sn foils backed by the thick substrate were irradiated by the laser pulses up to 300 J of energy with peak intensity higher than 1018 W/cm2. A transmission curved crystal spectrometer and a filter-stack spectrometer were used to measure the Kα line and bremsstrahlung x-ray spectral distribution, respectively. Both Kα and 70–200 keV x-ray yields decrease 3- to 5-fold for target backed by the substrate. 2- to 4-fold reduction of Kα and 70–200 keV x-ray yields for the 8.5 μm targets relative to 50 μm targets was observed. Moreover, a significant background x-ray emission generated from the target holder reduces the ratio of signal to noise. Adopting a low-Z material holder can mitigate the x-ray background noises. This study is instructive to optimize target design for the high-intensity laser-driven Kα or continuous x-ray sources.
Design of a high energy density experiment to measure the suppression of hydrodynamic instability in an applied magnetic field
Authors: Barbeau Zoe , Raman Kumar , Manuel Mario , Nagel Sabrina , Shivamoggi Bhimsen
Published: January 2022

A transverse magnetic field can suppress the hydrodynamic instability growth of an unstable plasma interface. This effect, of interest to inertial confinement fusion and astrophysics, has mostly been studied via simulation. Here, we present the design of an experiment at the National Ignition Facility (NIF) to demonstrate this effect in a laboratory. Simulations indicate that the timescale for the diffusion of the magnetic field across the mixing region should be at least comparable to the timescale of the instability growth in order to have a measurable suppression effect. This motivates the use of lower density target materials than usual high energy density (HED) hydrodynamics experiments to permit faster hydrodynamics and higher plasma conductivities (through higher temperature), for a given laser drive and magnetic field. We discuss a target design for creating a Rayleigh–Taylor unstable HED plasma interface that uses 320 mg/cc iodine-doped carbon foam as the heavy material, 20 mg/cc carbon foam as the light material, and a 6 μm amplitude, a 120 μm wavelength ripple machined at the interface, which shows a measurable suppression effect with a nominal NIF drive and a 30 T magnetic field (the present facility limit). Models indicate lower density foams that may display even larger suppression effects, as the Hohlraum drive also radiatively preheats the foam to permit even higher temperatures and, hence, higher conductivities.
Strain-tunable in-plane ferroelectricity and lateral tunnel junction in monolayer group-IV monochalcogenides
Authors: Priydarshi Achintya , Chauhan Yogesh Singh , Bhowmick Somnath , Agarwal Amit
Published: January 2022

2D ferroelectric materials are promising for designing low-dimensional memory devices. Here, we explore strain-tunable ferroelectric properties of group-IV monochalcogenides MX (M=Ge, Sn; X=S, Se) and their potential application in lateral field tunnel junction devices. We find that these monolayers have in-plane ferroelectricity, with their ferroelectric parameters being on par with other known 2D ferroelectric materials. Among SnSe, SnS, GeSe, and GeS, we find that GeS has the best ferroelectric parameters for device applications, which can be improved further by applying uniaxial tensile strain. We use the calculated ferroelectric properties of these materials to study the tunneling electroresistance (TER) of a 4 nm device based on a lateral ferroelectric tunnel junction. We find a substantial TER ratio of 103–105 in the devices based on these materials, which can be further improved up to a factor of 40 on the application of tensile strain.
Tuning the configuration of quantum dot molecules grown on stacked multilayers of heteroepitaxial islands
Authors: Rudin S. A. , Zinovyev V. A. , Smagina Zh. V. , Novikov P. L. , Shklyaev A. A. , Dvurechenskii A. V.
Published: January 2022

Arrays of Ge quantum dot molecules were grown by molecular beam epitaxy using a template, composed of a multilayer structure with layers of vertically aligned three-dimensional (3D) Ge islands buried in an Si crystal matrix with the Si capping layer on top. Depending on preparation conditions, the molecules assume various configurations, including a square frame with [001]–[010]-oriented sides. It was shown by scanning tunneling microscopy that the 3D islands are located closer to the buried SiGe mound centers with the increase of the capping layer thickness. The mechanism of the quantum dot molecule formation is ascribed to strain relaxation. It was confirmed by Monte Carlo simulations of heteroepitaxial Ge growth on the template, containing the buried Ge mound.
Spintronic emitters for super-resolution in THz-spectral imaging
Authors: Stiewe Finn-Frederik , Winkel Tristan , Sasaki Yuta , Tubandt Tobias , Kleinke Tobias , Denker Christian , Martens Ulrike , Meyer Nina , Parvini Tahereh Sadat , Mizukami Shigemi , Walowski Jakob , Münzenberg Markus
Published: January 2022

We investigate local THz field generation using spintronic THz emitters to enhance the resolution for micrometer-sized imaging. Far-field imaging with wavelengths above 100 μm limits the resolution to this order of magnitude. By using optical laser pulses as a pump, THz field generation can be confined to the area of laser beam focusing. The divergence of the generated THz beam due to laser beam focusing requires the imaged object to be close to the generation spot at a distance below the THz field wavelength. We generate THz-radiation by fs-laser pulses in CoFeB/Pt heterostructures, based on spin currents, and detect them by commercial low-temperature grown-GaAs (LT-GaAs) Auston switches. The spatial resolution of THz radiation is determined by applying a 2D scanning technique with motorized stages allowing step sizes in the sub-micrometer range. Within the near-field limit, we achieve spatial resolution in the dimensions of the laser spot size on the micrometer scale. For this purpose, a gold test pattern is evaporated on the spintronic emitter separated by a 300 nm SiO2 spacer layer. Moving these structures with respect to the femtosecond laser spot, which generates THz radiation, allows for resolution determination. The knife-edge method yields a full-width half-maximum beam diameter of 4.9±0.4 μm at 1 THz. The possibility to deposit spintronic emitter heterostructures on simple glass substrates makes them attractive candidates for near-field imaging in many imaging applications.
Pulsed Townsend measurement of electron swarm parameters in C4F7N–CO2 and C4F7N–N2 mixtures as eco-friendly insulation gas
Authors: Zhang Boya , Xiong Jiayu , Hao Mai , Yao Yuyang , Li Xingwen , Murphy Anthony B.
Published: January 2022

Recently, C4F7N mixtures have attracted attention as a promising SF6 alternative due to their low global warming potential and excellent electrical performance. In this study, we introduce a newly built experimental setup for pulsed Townsend measurements as well as the physical model for the acquisition of electron swarm parameters. The effective ionization rate coefficients, electron drift velocity, and density-normalized longitudinal diffusion coefficients in C4F7N and its mixtures with CO2 and N2 were obtained. The reduced critical electric field for pure C4F7N at 100 Pa is determined to be 1002 Td, while it decreases with increasing pressure because of the effect of ion kinetics during the discharge process. C4F7N shows good synergism with CO2 and N2. To have a dielectric strength equivalent to that of SF6, the mixing ratio of C4F7N in its mixtures with CO2 and N2 should be 18% and 12%, respectively. The results provide fundamental data for modeling discharges in C4F7N and its mixtures.
Crosslinguistic influence from Catalan and Yucatec Maya on judgments and processing of Spanish focus
Authors: Hoot Bradley , Leal Tania
Published: January 2022

Although a bilingual’s knowledge of one language can affect the other, crosslinguistic influence (CLI) is constrained: certain domains, such as the syntax-discourse interface, are more likely to be affected. Linguists have debated CLI’s nature and cause: the Structural Overlap Hypothesis identifies surface overlap between the languages as the key factor determining CLI, while the Interface Hypothesis highlights the role of processing overloads. Our study presents evidence from processing and judgments of a syntax-discourse interface property – information focus – in the Spanish of Yucatecan Spanish monolinguals, Yucatec Maya-Spanish bilinguals, and Catalan-Spanish bilinguals. The comparison across language dyads that realize information focus in different ways allows us to test predictions for language-specific effects of CLI. Using a forced-choice task to measure offline sentence preferences and a self-paced reading task to measure real-time processing, we find (i) language-specific CLI for Yucatec Maya bilinguals but (ii) no CLI for Catalan bilinguals and (iii) no significant differences in real-time processing. We conclude that these results provide partial support for the Structural Overlap Hypothesis but do not align with the Interface Hypothesis. We also examine the role of language dominance on CLI but find no such effects.
Common Envelope to Explosion Delay time Distribution (CEEDTD) of Type Ia Supernovae
Authors: Soker Noam
Published: January 2022

I use recent observations of circumstellar matter (CSM) around type Ia supernovae (SNe Ia) to estimate the fraction of SNe Ia that explode into a planetary nebula (PN) and to suggest a new delay time distribution from the common envelope evolution (CEE) to the SN Ia explosion for SNe Ia that occur shortly after the CEE. Under the assumption that the CSM results from a CEE, I crudely estimate that about 50% of all SNe Ia are SNe Ia inside PNe (SNIPs), and that the explosions of most SNIPs occur within a CEE to explosion delay (CEED) time of less than about ten thousand years. I also estimate that the explosion rate of SNIPs, i.e., the CEED time distribution, is roughly constant within this timescale of ten thousand years. The short CEED time suggests that a fraction of SNIPs come from the core-degenerate (CD) scenario where the merger of the core with the white dwarf takes place at the end of the CEE. I present my view that the majority of SNIPs come from the CD scenario. I list some further observations that might support or reject my claims, and describe the challenge to theoretical studies to find a process to explain a merger to explosion delay (MED) time of up to ten thousand years or so. A long MED will apply also to the double degenerate scenario.
An FPGA Based energy correction method for one-to-one coupled PET detector: model and evaluation
Authors: Ma C. , Zhao X. , Gao S. , Zhang F. , Wu G. , Li X. , Yu L. , Lu L. , Ye H. , Qian H.
Published: January 2022

A PET scanner based on silicon photomultipliers (SiPMs) has
been widely used as an advanced nuclear medicine imaging technique
that yields quantitative images of regional in vivo biology and
biochemistry. The compact size of the SiPM allows direct one-to-one
coupling between the scintillation crystal and the photosensor,
yielding better timing and energy resolutions than the light sharing
methods that have to be used in photomultiplier tube (PMT) PET
systems. To decrease the volume of readout electronics, a front-end
multiplexer with position decoder is a common choice for the
one-to-one system without a highly integrated application specific
integrated circuit (ASIC). However, in this case we cannot measure
each crystal's deposited energy inspired by an annihilation photon,
so the inter-crystal scatter (ICS) events will lead to the crystal
mispositioning and then deteriorate the detector intrinsic
resolution. Besides, considering the events rejection within the
energy window resulting from the gain dispersion and non-linear
outputs of the SiPMs, an energy correction mechanism is needed. Yet,
lack of the information of each crystal's energy will introduce
large energy correction error for the ICS events. For this issue, an
online energy correction mechanism implemented on a Kintext-7 Field
Programmable Gate Array (FPGA) device is presented in this
paper. Experiments in the laboratory were performed using an
8 × 8 segmented LYSO crystals coupled with an 8 × 8
SiPM (J-series, from ON Semiconductor) array which is under
22Na point source excitation. Test results indicate that both
the energy of the non-ICS and ICS events can be precisely corrected
and the energy resolution is better than 12 %. We also applied this
method to an actual clinical PET scanner under a 68Ge line
source to verify its multi-channel reliability.
Alginate in corneal tissue engineering
Authors: Kostenko Anastassia , Swioklo Stephen , Connon Che J
Published: January 2022

Corneal blindness is the major cause of vision impairment and the fourth-largest leading cause of blindness worldwide. An allograft corneal transplant is the most routine treatment for visual loss. Further complications can occur, such as transplant rejection, astigmatism, glaucoma, uveitis, retinal detachment, corneal ulceration due to reopening of the surgical wounds, and infection. For patients with autoimmune disorders, allografting for chemical burns and infections is contraindicated because of the risk of disease transmission and further complications. Moreover, corrective eye surgery renders the corneas unsuitable for allografting, further increasing the gap between donor tissue demand and supply. Due to these challenges, other therapeutic strategies such as artificial alternatives to donor corneal tissue are being considered. This review focuses on the use of alginate as a building block of therapeutic drugs or cell delivery systems to enhance drug retention and encourage corneal regeneration. The similarity of alginate hydrogel water content to native corneal tissue makes it a promising support structure. Alginates possess desired drug carrier characteristics, such as mucoadhesiveness and penetration enhancing properties. Whilst alginates have been extensively studied for their application in tissue engineering, with many reviews being published, no reviews exist to our knowledge directly looking at alginates for corneal applications. The role of alginate in drug delivery to the surface of the eye and as a support structure (bioinspired tissue scaffold) for corneal tissue engineering is discussed. Biofabrication techniques such as gel casting, electrospinning, and bioprinting to develop tissue precursors and substitutes are compared. Finally, cell and tissue encapsulation in alginate for storage and transport to expand the scope of cell-based therapy for corneal blindness is also discussed in the light of recent applications of alginate in maintaining the function of biofabricated constructs for storage and transport.
Algorithm for calculating the power factor of a rotary mixer drive
Authors: Chupshev A V , Teryushkov V P , Konovalov V V , Fomina V
Published: January 2022

The purpose of the research was to develop a methodology for calculating the power factor of the rotary agitator unit drive with its components and an algorithm for their determination, implemented in the form of a computer program. The structural scheme of the bulk material mixer with the developed agitator unit is given. The definition of the required parameters is realized on the base of the known expressions and operating parameters of the mixer. The developed technique and calculation algorithm, which is realized in the MathCAD mathematical package, allow determining the peripheral velocity profile parameter of the material and the hydraulic resistance coefficient of the working body, the power factor and the mixing capacity factor, which allows calculating the torque and power required for material mixing by a rotary mixer with a vertical shaft of the developed design.
Changes in the parameters of photosynthetic maize activity with applying micronutrient fertilizers
Authors: Gavryushina I V , Semina S A , Paliychuk A S , Nikulina E V
Published: January 2022

The most important factor that determines the yield of agricultural crops is mineral nutrition. It is important to supply the plants in the required amount and the optimal ratio of basic nutrients and microelements. Foliar treatment is the most rational way to apply micronutrient fertilizers. The current research aimed at examining the species (Azosol 36 Extra, 3.0 l/ha; Aquarin 5, 3.0 l/ha) and the terms of application (5 maize leaves; 8 maize leaves; 5 leaves + 8 maize leaves) of micronutrient fertilizers, depending on the early ripening of the hybrid, providing the formation of the best indicators of photosynthetic activity, was carried out on leached heavy loamy chernozem. When foliar treatment of an early ripe hybrid with Azosol 36 Extra solution, the increase in the total leaf surface of sowing in relation to options with water on a natural agro background was 3.0%, and from Aquarin 5-9.1%, and for the mid-early, the increase was 4.3 and 6.9%, respectively. Against the background of N110P70K40, the gains varied from 4.0 to 5.9%, but no significant advantage, both types of micronutrient fertilizers and in terms of foliar treatment, was not revealed. The use of Azosol 36 Extra on the natural agro background promoted an increase in the total photosynthetic potential by 2.7-4.1% compared to the treatment with water, the effect of Aquarin 5 was more effective, the increase was 6.9-8.9%. With the improvement of root nutrition conditions, the increase from Azosol 36 Extra was obtained a bit more - 4.1 -5.8%, and from Aquarin 5, on the contrary, less (3.7-5.6%). Variants with foliar treatment with Azosol 36 Extra in the phase of eight leaves and double application, the increase varied from 7.5-7, 9% on a natural agricultural background to 13.2% on an improved one. Aquarin 5 had a better effect on plants during foliar treatment in the phase of five leaves of maize, but the increase was 2.7-8.5%.
Hydrogen diffusivity and tensile properties degradation in SLMed Inconel 718
Authors: Aiello F , Beghini M , Bertini L , Macoretta G , Monelli B D , Valentini R
Published: January 2022

Besides elevated temperature applications, Inconel 718 is widely chosen for components subjected to heavy loads operating in aggressive environments, which can promote the production of hydrogen on the metal surface. Selective Laser Melting (SLM) is an emerging technology for the production of structural components in Inconel 718 or Inconel 625 alloys, allowing to create functionally optimized shapes and overcome the traditional manufacturing limitations. However, the SLM process introduces a peculiar microstructure and severe residual stresses that can affect hydrogen migration and accumulation. While the mechanical properties were deeply investigated in recent years, the resistance of SLMed Inconel 718 to the Hydrogen Embrittlement (HE) is still an open issue. The present work deals with a preliminary assessment of the hydrogen embrittlement susceptibility of the SLMed In718 in the as-built condition. Slow strain rate tests were carried out on unnotched specimens that were pre-charged by electrochemical cathodic charging. Fractographic analyses, carried out with a Scanning Electron Microscope (SEM), were used to identify the effects produced by the hydrogen intake on the material microstructure. The material resulted to be susceptible to hydrogen embrittlement, featuring a significant ductility reduction in presence of extremely elevated hydrogen concentrations. The hydrogen content was measured by employing the Hot Extraction Method (HEM), for each mechanical test. Due to a low diffusivity value, hydrogen penetrates only within a thin external layer of the specimen. Therefore, to identify the concentration profile, the effective hydrogen diffusion coefficient was identified and the hydrogen diffusion was simulated using Fick’s equation. The loss in mechanical resistance was then correlated to the hydrogen concentration near the fracture onset.
Experimental analysis on the resistance of fixing nails for spine cages
Authors: La Rosa G , Mineo R , Barbagallo R , Tosto C
Published: January 2022

Arthrodesis is one of the most common surgical treatment for the management of pathologies concerning the intervertebral discs. Special cages replace the intervertebral disc and realize the fusion between the vertebral body, often together with a fixing plate, screws, and rods. An alternative method is a cage that contains integrated screws, designed with suitable holes, it allows an easier insertion of fixing system during surgery. Mt Ortho company offers a cage equipped with two diverging locking nails in Ti6Al4V-ELI titanium alloy. These nails are placed directly inside the cage inclined by 30° with respect to the horizontal. This paper, performed in collaboration with Mt Ortho, reports the experimental tests aimed at evaluating the performance of locking nails under pull-out stresses. To evaluate the nails pull-out in a more physiological way, together to the standard condition, tests were performed on a composite layer made of wood and foam. Furthermore, the notch effects generated by the locking nails are qualitatively evaluated by photoelastic analysis, in view of a geometry able to reduce the stress concentration factor on the bone tissue, without reducing the pull-out resistance.
Sound of a Composite Failure: An Acoustic Emission Investigation
Authors: Barile C , Casavola C , Pappalettera G , Vimalathithan P K
Published: January 2022

The failure progression characteristics of adhesively bonded Carbon Fiber Reinforced Polymer (CFRP) composites are investigated using Acoustic Emission (AE) technique. Different failure progression modes such as matrix cracking, fiber breakage, delamination and through-thickness crack growth releases AE waveforms in different frequency domains. The characteristic features of these different AE waveforms are studied in Mel Scale, which is a perpetual frequency scale of average human hearing frequency. The recurring noise in the recorded waveforms has been identified more efficiently when the waveforms are analysed in Mel Scale. The recorded AE signals from the adhesively bonded CFRP under static tensile loading are stretched to match the Mel filter banks. The sampling rate of the recorded signal is adjusted from 1 MHz to 20 kHz. Following that, the Mel spectrogram and its cepstral coefficients are used for identifying the different failure modes from which the AE signals are generated. A comprehensive comparison of the AE analysis in Mel scale with conventional waveform processing techniques such as Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Wavelet Packet Transform (WPT) and Hilbert-Huang Transform (HHT) has been made. The advantages and further applications of Mel Scale over traditional waveform processing techniques in defining the failure modes in the composites are also discussed.
Damage Detection in Composite Materials by Flexural Dynamic Excitation and Accelerometer-Based Acquisition
Authors: Loi G , Uras N , Porcu M C , Aymerich F
Published: January 2022

Composite materials provide many advantages over more conventional materials. However, their susceptibility to impact damage can question their use in critical load-bearing structures, and efficient methods are needed for early damage detection. To this purpose, the nonlinear vibro-acoustic modulation (VAM) technique applies a low-frequency pump excitation and a high-frequency probe excitation to exploit the onset of harmonic components around the probe frequency of the damaged structural response. The VAM technique has been widely studied on structures instrumented with piezoceramic transducers used for both actuation and sensing, but few attempts have been made to use equipment typical of modal testing, such as shakers and accelerometers. In this study, the VAM technique is applied to a composite laminate beam by employing an electro-dynamic shaker to generate low-frequency flexural excitation, a low-profile piezoceramic transducer to introduce the probe wave, and a micro-accelerometer to sense the structural response. Three resonance low frequencies and two acoustic frequencies are considered in different testing scenarios, at increasing levels of excitation amplitude. The results show a general good performance of the technique with the adopted experimental setup, the choice of the probe frequency and the higher level of the pump excitation having a significant impact on its sensitivity.
Full-field monitoring methods for damage analysis on aeronautical CFRP specimens under fatigue loads
Authors: Nobile R , Panella F W , Pirinu A , Saponaro A
Published: January 2022

The present paper is focused on full-field experimental monitoring procedures to be employed during HCF fatigue testing on two series of CFRP open hole samples. Two different experimental methodologies based on thermographic techniques and displacement measurements with Digital Image Correlation (DIC) analysis are employed for damage settlement and evolution to be detected up to failure, together with correspondent compliance analysis. Combined monitoring approaches, based on thermo-elastic and dissipative phenomena, together with stiffness properties variations, are claimed to offer precise damage state localization during tests in real time; in addition, DIC analysis is performed during low-frequency fatigue cycle is studied for better failure prediction and damage location. The thermal parameters and experimental compliance correlation seem to indicate similar signal variation during damage progress and after proper data elaboration; contemporaneous raw thermal measurements in critical zones of specimens under fatigue life offer a kind of delamination recognition at specific layer interface and location, as well as propagation before final failure. Sample under tensile load on the other hand reveal delaminations indirectly on the surface. In addition, non-destructive thermographic and ultrasound tests are performed at regular intervals during fatigue life.
Composite-to-metal multi-bolt joints: a simplified FE analysis method
Authors: Belardi V G , Fanelli P , Vivio F
Published: January 2022

This paper presents a modified version of the Composite Bolted Joint Element (CBJE) that can be employed for the finite element analysis of double-lap joints made up of metal and composite material plates. The CBJE makes use if the theoretical definition of composite bolted region that is solved to analytically define the behavior of the joint. The solution is utilized to obtain the stiffness of the bolted region and the bolt-hole contact stiffness that are transferred to the CBJE. The definition based on the analytical solution allows to balance the accuracy and the computational effort of the solution. The results of CBJE for hybrid double-lap joints is compared with a 3D FE solid demonstrating a highly remarkable matching.
Preliminary design of an anthropomorphic cutting and potting system for automated agriculture
Authors: Delogu M , Uggiosi D , Barbieri R , Pierini M
Published: January 2022

The study presented is part of the Rural Development Programme of the Tuscany Region and the European Union: the objectives are to limit the number of manual operations, to enhance technological transfer operations, to share best practices and to reduce the carbon footprint of the Scindapsus cuttings production chain. In this context, the work presents the approach to a preliminary design of an anthropomorphic system for automated cutting and potting of cuttings. For a better understanding of the current procedures and solutions, a critical analysis of the State of the Art of agricultural automation processes available in the literature was carried out. This study was developed in parallel with market research to identify the custom components to be produced to make a choice consistent with the technical specifications. The design has dealt with the system for handling and preparing the cuttings through panels and conveyor belts, starting from the needs defined in the initial phase. The analysis considered, both at a mechanical and functional level (evaluation of times and methods), the layout of production space with a high degree of automation for cutting and potting cuttings, with particular attention to the issues of the workplace safety and the maintainability of the elements: the best configuration of resources, personnel and equipment were designed through a what-if scenario analysis populated by deterministic and stochastic events.
Elucidating the Population Structure and Genetic Diversity of Indian Puccinia striiformis f. sp. tritici Pathotypes Based on Microsatellite Markers
Authors: Gangwar Om Prakash , Kumar Subodh , Bhardwaj Subhash Chander , Prasad Pramod , Lata Charu , Adhikari Sneha , Singh Gyanendra Pratap
Published: January 2022

In India, systematic wheat yellow rust survey and pathotype (race) analysis work began in 1930. However, information on population structure and genetic diversity of yellow rust pathogen has not been available. To address this, we conducted studies on population structure and genetic diversity of Puccinia striiformis f. sp. tritici (Pst) pathotypes using 38 simple sequence repeat primer-pairs. Bayesian assignment and discriminant analysis of principal components indicated the presence of two distinct Pst subpopulations (Pop1 and Pop2) along with 37.9% admixed pathotypes. The unweighted pair-group method with arithmetic mean also categorized these pathotypes into two major clusters. Principal coordinates analysis explained 20.06 and 12.50% variance in horizontal and vertical coordinates, respectively. Index of association (IA) and the standardized index of association ([Formula: see text]) values showed that Pst subpopulations reproduced asexually (clonally). In total, 102 alleles were detected, with the expected heterozygosity (Hexp) per locus ranging from 0.13 to 0.73, with a mean of 0.47. The average polymorphic information content value of 0.40 indicated high genetic diversity among pathotypes. Analysis of molecular variance revealed 12% of the total variance between subpopulations, 11% among the pathotypes of each subpopulation, and 77% within pathotypes. A significant moderate level of genetic differentiation (FST = 0.122, P < 0.001) and gene flow (Nm = 1.80) were observed between subpopulations. The Pst virulence phenotypes showed a weak positive correlation (R2 = 0.027, P < 0.02) with molecular genotypes.