bluuebunny/crossref_metadata_2025 huggingface dataset:
Exciton-polariton dynamics of the single site-controlled quantum dot-nanocavity in the coexisting strong-weak coupling regime
Authors: Huang Jiahui , Liu Wei , Sarihan Murat Can , Cheng Xiang , Miranda Alessio , Dwir Benjamin , Rudra Alok , Kapon Eli , Wong Chee Wei
Published: March 2023

Deterministic positioning single site-controlled high symmetric InGaAs quantum dots (QDs) in (111)B-oriented GaAs photonic crystal cavities with nanometer-scale accuracy provides an idea component for building integrated quantum photonic circuits. However, it has been a long-standing challenge of improving cavity Q-factors in such systems. Here, by optimizing the trade-off between the cavity loss and QD spectral quality, we demonstrate our site-controlled QD-nanocavity system operating in the intermediate coupling regime mediated by phonon scattering, with the dynamic coexistence of strong and weak coupling. The cavity-exciton detuning-dependent micro-photoluminescence spectrum reveals concurrence of a trend of exciton-polariton mode avoided crossing, as a signature of Rabi doublet of the strongly coupled system. Meanwhile, a trend of keeping constant or slight blue shift of coupled exciton–cavity mode(CM) energy across zero-detuning is ascribed to the formation of collective states mediated by phonon-assisted coupling, and their rare partial out-of-synchronization linewidth-narrowing is linked to their coexisting strong-weak coupling regime. We further reveal the pump power-dependent anti-bunching photon statistical dynamics of this coexisting strong-weak coupled system and the optical features of strongly confined exciton-polaritons, and dark-exciton-like states. These observations demonstrate the potential capabilities of site-controlled QD-cavity systems as deterministic quantum nodes for on-chip quantum information processing and provide guidelines for future device optimization for achieving the strong coupling regime.
Description and dosimetric features of lithium borate glass doped with transition metals for thermoluminesce, a re-evaluation
Authors: G I Efenji , Mustafa Iskandar Shahrim , kamgba F A , Ogunleye O O , Khazaalah Thair Hussein , Ezra Nabasu Seth , Naeem Hayder Salah , Shariff Hanisha Mohd , Jamil Munirah , Abdul Malik Muhammad Fadhirul Izwan
Published: March 2023

The investigation of borate glasses and the dosimetric features of lithium glass system began as an experiment in science as well as an attempt to describe it composition of amorphous materials in general. This research improved our knowledge of the structure and behaviour of borate glasses. There are a few exceptions to the fact that silicate and borosilicate glasses meet most scientific and industrial needs. However, there are some benefits to borate glasses above silicate glasses which are not widely understood or explored. However, certain features of transition metal (Dysprosium) doped borate glasses, like their propensity for water, require that they would be carefully chosen, constructed, or manufactured to fulfil the demands of a certain application. The goal of this study is to investigate and report on some of important characteristics of binary borate glasses. It also includes specific instructions designed for several purposes in which the published studies are examined in relation to technical knowledge or needed skills.
Physical properties of Ni: Co3O4 thin films and their electrochemical performance
Authors: El-Araby Mahmoud , Mostafa Khalefa Moatasem , Mukherjee Ayan , Mohaseb M A , Aboud Ahmed A
Published: March 2023

In this research work, we have deposited cobalt oxide as pure and Ni-doped thin films using spray pyrolysis. The concentration of Ni has been changed from 0 to 6 wt% in all films while other deposition parameters are fixed. The characterization of deposited films has been c using X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), x-ray photoelectron microscope (XPS), scanning electron microscope (SEM), and optical spectroscopy. The XRD results confirm the formation of Co3O4 as the low-temperature stable phase of cobalt oxide and the successful doping with nickel. The XRD also shows the preferred orientation of growth of film is along the (111) plane and the crystallite size was found to decrease with increasing Ni content. The SEM micrograph of the deposited film surfaces revealed that the samples are porous and in some parts of the sample, the particles are agglomerated due to doping. The Ni doping was confirmed by both EDX and XPS. The Ni concentration was found to increase according to dopant concentration. The XPS data of the 4 wt% film has been recorded which confirms the existence of Ni+2 in the deposited films. Both optical transmission and reflection spectra have been recorded using a spectrophotometer. The band gap values have been found to decrease upon Ni-doping. The electrochemical properties of the pure and nickel-doped cobalt oxide films were measured by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 0.3 M KOH electrolyte. The specific capacitance of 4 wt% Ni doped Co3o4 was found to be 804 Fg-1 at a 2 mVs−1 scan rate which is 90% higher than pure films. The important property of this material is that it shows excellent retention of 96% and remains almost constant for 10000 cycles. The impedance analysis reveals that 4 wt% Ni doped cobalt oxide film has the lowest RS value of 0.2 Ω cm−2 and lowest RCT value of 0.05 Ω cm−2 in comparison to other films which have excellent super-capacitive nature. These outstanding electrochemical properties of 4 wt % Ni-doped Co3O4 thin film have made it a potential candidate for anode material in supercapacitor devices.
Topological charge measurement in a four-level single layer graphene system
Authors: Saeed Saeed Hassan , Lafta Holya A , Abbass Rathab , Fahim Fatima Safaa , Adhab Ayat Hussein , Shams Marwah A , Kadhim Athmar Ali , Gatea M Abdulfadhil
Published: March 2023

In this letter we have proposed a four-level graphene monolayer system for identifying the topological charge of Laguerre–Gaussian light. Here, we have shown that due to the four-wave mixing mechanism in the monolayer graphene system, a weak signal beam can be generated due to quantum coherence and interference effect. We have discussed the spatially dependent linear absorption spectrums of the weak probe and new generated signal beams via quantum mechanical density matrix formalism. We have found that by numbering the spot areas of the probe and signal beams, one can realize the topological charge of the Laguerre–Gaussian beam interacts by monolayer graphene system. Moreover, we have realized that for some topological charge the new generated signal beam can be amplified in the graphene system.
Variation of Small Scale Magnetic Fields Over a Century using Ca-K Images as Proxy
Authors: Singh Jagdev , Priyal Muthu , Ravindra B. , Bertello Luca , Pevtsov Alexei
Published: March 2023

A combined uniform and long-time series of Ca-K images from the Kodaikanal Observatory, Mount Wilson Observatory and Mauna Loa Solar Observatory was used to identify and study the Ca-K small-scale features and their solar cycle variations over a century. The small scale features are classified into three distinct categories: enhanced network, active network and quiet network. All these features show that their areas vary according to the 11 yr solar cycle. The relative amplitude of the Ca-K network variations agrees with that of the sunspot cycle. The total area of these small-scale features varies from about 5% during the minimum phase of the solar cycle to about 20% during its maximum phase.
A novel hermetic detection system of KAPAE for measuring multiphoton decays of positronium
Authors: Park H.W. , Jeong D.W. , Jegal J. , Khan A. , Kim H.J.
Published: March 2023

The detection system of the Kyungpook National University Advanced Positronium Annihilation Experiment (KAPAE) has a 4π coverage with fine segmentation for measuring multi- photon decays of positronium to improve the charge (C), charge-parity (CP), and charge-parity-time reversal (CPT) violations in lepton sector as well as for studying rare decays. In addition, various exotic decays of positronium can be studied with the KAPAE detector. In the KAPAE, all aspects of the detector design, fabrication, and data analysis for physics studies related to positronium annihilation are covered. In this paper, we describe the above-mentioned first fully assembled detection system developed for KAPAE, which consists of a trigger and a gamma-ray detector. The newly proposed multi-layered trigger consists of a 22Na positronium source deposited on a plastic scintillator and a silicon photomultiplier (SiPM), and the gamma-ray detector contains an aerogel at the centre in a nitrogen environment. The gamma-ray detector minimizes pile-up events by fine segmentation of 196 Bi4Ge3O12 (BGO) crystal scintillators, whose scintillation lights from both sides are readout by the SiPM. The signals of a 392-channel SiPM are fed to a preamplifier followed by a 65 MHz flash analog-to-digital converter (FADC). In this paper, the KAPAE detector design, fabrication, and performance are presented.
System upgrade for μBq/m3 level 222Rn concentration measurement
Authors: Liu Y. , Zhang Y.P. , Liu J.C. , Guo C. , Yang C.G. , Zhang P. , Tang Q. , Xu Z.F. , Li C. , Guan T.Y. , Wang S.B.
Published: March 2023

The Jiangmen Underground Neutrino Observatory (JUNO), a
20 kton multipurpose underground liquid scintillator detector, was
proposed for the determination of the neutrino mass hierarchy as
primary physics goal. The central detector will be submerged in a
water Cherenkov detector to lower the background from the
environment and cosmic muons. Radon is one of the primary background
sources. Nitrogen will be used in several sub-systems, and a highly
sensitive radon detector has to be developed to measure its radon
concentration. A system has been developed based on 222Rn
enrichment of activated carbon and 222Rn detection based on the
electrostatic collection. This paper presents the detail of a
μBq/m3 level 222Rn concentration measurement system
and gives detailed information about how the adsorption coefficient
was measured and how the temperature, flow rate, and 222Rn
concentration affect the adsorption coefficient.
Where does the irrigated water in the Tarim Basin go? A hydrological analysis of water budgets and atmospheric transport
Authors: Liu Jiahui , Sun Ting , Ni Guangheng
Published: March 2023

Irrigated agriculture plays a crucial role in the local economic and social development of the Tarim Basin (TB), but its sustainability is threatened by water scarcity due to the arid environment. In this study, we investigate the impact of irrigation on the atmospheric hydrological cycle in the region using the weather research and forecast model. We conduct simulations for a three month period under two scenarios: present-day and future warming. Our results show that, in the present-day scenario, 90.5% of irrigated water is transported via atmospheric hydrological processes, with precipitation and water vapor transport being the dominant components. However, in the future warming scenario, more atmospheric water (45.2%) will leave the area due to weakened wind regimes, resulting in significant water loss. Furthermore, our analysis using the HYbrid Single Particle Lagrangian Integrated Trajectory model indicates that irrigation contributes to extreme rainfall events, and the southwestern TB is a primary destination for irrigated water. Our findings highlight the urgency of addressing the sustainability of irrigated agriculture and local water resources in the face of impending global warming.
Spectral structure of two-mode Rabi–Stark model
Authors: Liu Yan , Qiu Fangcheng , Liu Ronghai , Ma Jinying , Yan Zhanyuan
Published: March 2023

The analytical solutions of the two-mode Rabi–Stark model (tmRSM) are obtained by using the Bogoliubov operators approach in

s
u
(
1
,
1
)

Lie algebra space, which fit the exact numerical results well. The structure of the energy spectra is related to many fundamental physics characters such as symmetry, quantum phase transition (QPT), spectral collapse etc. In this paper, the spectral structure of tmRSM is discussed analytically. The regular energy spectra are given by the zeros of the G-function, and the poles appearing in the G-function are responsible for the exceptional solutions. The double degenerate exceptional solutions could be predicted by discussing the divergence of the coefficients in the G-function. If the numerator and denominator of

Ω
n

vanish, the lowest double degenerate exceptional solutions for the nth energy levels would be located, including the first-order QPT point, the corresponding energy (

−
Δ

/

U

) is independent of the coupling strength and the energy level, even independent of the Bargmann index q. While, the nondegenerate exceptional solutions can be reproduced by the nondegenerate exceptional G-functions, the results show that more nondegenerate exceptional solutions would be found in the subspace with larger q. Then, the regular solution and two kinds of exceptional Juddian solutions of tmRSM are accurately located. The spectral collapse energy are dependent on the strength of Stark coupling and the frequency of two-level system, and Stark coupling could results in the limit of E
0 pole line is higher than that of E

n
pole lines, which may cause more energy levels separate from the collapse energy.
Quantum resetting in continuous measurement induced dynamics of a qubit
Authors: Dubey Varun , Chetrite Raphael , Dhar Abhishek
Published: March 2023

We study the evolution of a two-state system that is monitored continuously but with interactions with the detector tuned so as to avoid the Zeno affect. The system is allowed to interact with a sequence of prepared probes. The post-interaction probe states are measured and this leads to a stochastic evolution of the system’s state vector, which can be described by a single angle variable. The system’s effective evolution consists of a deterministic drift and a stochastic resetting to a fixed state at a rate that depends on the instantaneous state vector. The detector readout is a counting process. We obtain analytic results for the distribution of number of detector events and the time-evolution of the probability distribution. Earlier work on this model found transitions in the form of the steady state on increasing the measurement rate. Here we study transitions seen in the dynamics. As a spin-off we obtain, for a general stochastic resetting process with diffusion, drift and position dependent jump rates, an exact and general solution for the evolution of the probability distribution.
Entanglement at the interplay between single- and many-bodyness
Authors: Reslen Jose
Published: March 2023

The tensor network representation of the ground state of a Bethe chain is analytically obtained and studied in relation to its entanglement distribution. Block entanglement displays a maximum at the interplay between single- and many-bodyness. In systems of two fermions, tensor networks describing states with substantial many-body entropy cannot be written as a sequence of next-neighbor unitaries applied on an uncorrelated state, but need four-next-neighbor unitaries in addition. This differs from the idea that ground states can be obtained as a sequence of next-neighbor operations applied on an initial tensor network lacking many-body correlations. The work uncovers the transcendence of the notion of many-bodyness in the implementation of protocols based on matrix product states.
Revealing atomic structure evolution of an Al-1.5Fe alloy in the liquid state using X-ray total scattering and empirical potential structure refinement
Authors: Huang S , Qin L , Zhao J , Xiang K , Luo S , Michalik S , Mi J
Published: March 2023

We used in-situ real-time synchrotron X-ray total scattering and empirical potential structure refinement method to study the evolution of atomic structure of an Al-1.5Fe alloy melt from 750°C to 630 °C. Detailed data normalization and analyses for the total scattering data were presented in order to achieve sensible atomic structure simulation using the empirical potential structure refinement (EPSR) method with constraints of R-factor is <10-3. Reliable construction of 3D atomic structure of Al-Fe melt in the temperature range reveals that more Al atoms coordinate Fe atoms and the Fe-centered clusters get more compact with the temperature decreases. More systematic work linking the liquid structure to the nucleation structure is under way.
The cooling rate effects on the Nb-B inoculant potential of refining grains and dendritic scale in 6201 alloy
Authors: Saldanha F E , Sousa S M A , Gouveia G L , Spinelli J E
Published: March 2023

Nb-B refiners are thought to be more stable than Ti-based refiners, becoming promising inoculants for Al alloys. However, the combined effect of adding NbB on dendritic scale and grain size (GS) with a wide range of solidification cooling rates remains unknown. It is well known that the shape of the α-Al phase is determined by a balance between inoculating components content/type and cooling rate. The inoculation of Al alloys with Ti-based inoculants, for example, significantly lowers GS while having no significant effect on secondary dendritic arm spacing (SDAS). Increased cooling rate, on the other hand, results in grain refinement, but only to a limited extent. Because of a combination of appropriate mechanical properties and suitable electrical conductivity, the 6201 alloy is widely employed in the transmission and distribution of electricity. Despite being a thermomechanically treated alloy, it goes through a melting and solidification process first, which entail research on this level of processing. ln order to assess the impact of adding NbB to the 6201 alloy’s refinement level (either macro or microscopic), directional solidification (DS) and centrifugal casting (CC) processes were utilized to obtain samples for examination. For the DS samples, cooling rates were determined, whereas for the CC samples, they were approximated for two alloys: 6201 (reference) and 6201-0.5wt.%Nb-0.1wt.%B alloys. Comparing the refined and non-refined alloy results, the GS of the DS 6201-NbB alloy was much smaller (about 13 times) across a range of cooling rates from 0.5 K/s to 20 K/s, whereas only 3 times smaller GS values were detected for CC samples at higher cooling rates. For particular cooling rates of 2.5 K/s and 240 K/s, the GS/SDAS ratios of values related to slow and fast cooling were 6.9 and 6.2, demonstrating that the cooling rate sensitivity of both GS and SDAS was similar in the NbB-inoculated alloy.
The Effects of Melt Pool Geometry and Scan Strategy on Microstructure Development During Additive Manufacturing
Authors: Chadwick Alexander F , Voorhees Peter W
Published: March 2023

During the powder bed fusion additive manufacturing (AM) process, hundreds of grains may solidify simultaneously within the melt pool, depending upon the processing conditions and the grain size of the base plate and powder. Thus, a small variation in the shape of the melt pool or scan strategy may result in very different as-printed microstructures, since new grains may become more favourably aligned with the overall direction of growth. The microstructure affects the performance of the additively built component, and it is therefore critical to understand the interplay between the initial microstructure, material properties, heat source, and scan strategy on determining the as-printed microstructure. We examine columnar grain growth during AM using a phase-field model to perform simulations with single melt pools predicted by the cylindrically symmetric Rosenthal solution. Quantitative measures of the competitive grain growth are extracted from the simulation data. To aid in their understanding, we map these quantities onto visualizations of the microstructure and compare them to the inverse pole figure map, from which we find that the crystallographic directions of the grains that grow closest to the centre of the laser track may not be preferentially aligned with the scan direction.
Effects of melt pool flow on porosity levels in arc welding
Authors: Wu F. , Falch K. V. , Drakopoulos M. , Mirihanage W. U.
Published: March 2023

Arc welding is one of the widely used approaches for joining metals. During the arc welding process, an electric arc creates intense heat to fuse metals that forms the melt pool between the parts to be welded together. Intensive flow fields are observable within the fusion weld pools as a result of multiple driving forces. The flow patterns within the melt pool significantly determine the shape of the weld joint and other attributes of the solidified joint, such as microstructure and defects. Porosity is one of the solidification-related defects that can bring a detrimental impact. During the formation and solidification of weld pools, gas bubbles that are formed can be driven in or out from the pool by the flow. In this work, employing in situ synchrotron X-rays, we have observed how different flow conditions and air-liquid interface are contributed to retaining and releasing the gas bubbles that formed during the arc welding. The results suggest that underpinning driving forces, such as electromagnetic forces, act on molten metal to retain the pores inside the weld joints; but, gravity-driven effects can contribute to reduce the porosity, with appropriate process conditions.
Understanding Ni-modified AlSi10Mg alloys from slow to rapid solidification
Authors: Moura DA , Gouveia GL , Figueira G , Gargarella P , Spinelli JE
Published: March 2023

Al-Si-Mg alloys are widely employed in a variety of industries, including aerospace, automotive, and microelectronics. This is because of its low density, acceptable mechanical properties, acceptable corrosion resistance, and inexpensive application cost. Because of its advantageous fluidity, limited solidification interval, and low volumetric contraction, Al-(9-11) wt.% Si-(0.2-0.5) wt.% Mg casting alloys have been employed in Laser-Powder Bed Fusion (LPBF) printing techniques. Despite being used as commercial alloys, their mechanical properties still need to be improved. In line with this, the current focus of aluminum-based alloys development for additive manufacturing is mostly on the modification of commercially available alloys. One of the possibilities is the reinforcement of cast alloys that may be processed using additive manufacturing technologies. Nickel is used as an alloying element in this study to generate the Al3Ni intermetallic, which is distinguished by its improved strength. Furthermore, the thermal stability of the Al3Ni may be a benefit, particularly for high-temperature applications. Under such context, the present study aims to investigate the solidification under low and high cooling rates of three alloys: AlSi10Mg-1Ni, AlSi10Mg-2Ni, and AlSi10Mg-3Ni (wt.%). Samples were obtained by directional solidification (DS) and laser surface remelting (LSR) and the cooling rates were calculated for both DS samples and with extrapolation for the more refined LSR samples as well as with the use of models from the literature. With the increase in Ni content, the Al3Ni mass fraction increased from 3% to 5% and then to 7.5%, according to CALPHAD computations. The growth rate of the DS samples was lowered in the direction of Ni addition: 1 Ni > 2Ni > 3 Ni. SEM data will be presented, with a focus on the rapid solidified melt pool samples and their features.
Modelling of microstructures development in laser powder bed fusion process – Application to IN718 superalloy
Authors: Camus T , Maisonnette D , Baulin O , Senninger O , Guillemot G , Gandin C A
Published: March 2023

In laser powder bed fusion (L-PBF) process, a deposited powder layer is melted by a laser and solidifies when the laser moves away. During solidification, the microstructure of the part is formed due to both epitaxial grain growth and nucleation. This structure has a strong influence on the final mechanical properties of parts and is influenced by the choice of process parameters such as the laser power and velocity or the scanning strategy. As a consequence, the prediction and characterization of this microstructure is of prime interest considering size, crystallographic orientations and shapes of grains. Among the approaches reported in the literature to model microstructure development, the Cellular Automaton (CA) method is a relevant choice to describe grain structure evolution. This model has been adapted to investigate microstructure formation during L-PBF process applied on an IN718 nickel-base superalloy. The steady state thermal behaviour at the scale of the melt pool is analysed and used to compute the development of the structure. This structure is computed at the scale of the part also considering realistic scanning strategies.
Gabriel Faivre: his legacy on eutectic solidification
Authors: Akamatsu S
Published: March 2023

In the honor of Gabriel Faivre (1944-2020), I will present a review of major scientific contributions to the understanding of the dynamics of eutectic growth patterns. From the end of the 1980s, Gabriel Faivre undertook a systematic research in solidification guided by the new concepts of the nonlinear physics of out-of-equilibrium pattern formation. Drawing on his outstanding capabilities as an experimentalist, he refined the method of in situ directional solidification of model alloys. With constant reference to physics and metallurgy, he succeeded in carrying out a high-level research, keen to reach strong qualitative impact and quantitative accuracy. Gabriel Faivre made key discoveries, together with coworkers and young researchers in Paris, and in collaboration with materials scientists and physicists in France and abroad. From symmetry breaking instabilities to eutectic cells and dendrites, over rod-like and labyrinth patterns, full light has been shed onto new phenomena, fascinating to the eye and the mind. During the last decade, Gabriel Faivre mentored an in-depth analysis of interfacial-anisotropy effects on coupled-growth patterns, thus reconciliating the theories of regular eutectics and crystal-orientation dependent eutectic-grain growth. Being both a rigorous scientist and a generous colleague, he left us a vast legacy of prospective research topics in solidification and crystal-growth science. Sharing his knowledge of fine arts and humanities, Gabriel Faivre also instilled the best of intellectual thinking in those who were fortunate enough to work with him.
Formation of locked-lamellar grains in a slightly hypoeutectic Al-Al2Cu alloy during thin-sample directional solidification
Authors: Medjkoune M , Bottin-Rousseau S , Carroz L , Prévot G , Croset B , Micha J S , Akamatsu S
Published: March 2023

We studied the formation and growth of locked-lamellar microstructures in a thin sample of a slightly hypoeutectic Al-Al2Cu alloy. The coupled-growth dynamics, including early stages and steady-state regimes, was observed optically in real time during directional solidification. The orientation of the α (Al) and θ (Al2Cu) crystals was measured ex situ in a series of eutectic grains by X-ray Laue microdiffraction. A nucleation event of a θ crystal on a pre-existing α crystal, and the subsequent growth of a eutectic grain with a type-C orientation relationship, that is, with a coincidence of {123}-α and {100}-θ planes, were observed in situ. In type-C eutectic grains, lamellar locking occurred parallel to the low-energy coincidence plane. A regular (floating) coupled-growth dynamics was observed in misoriented eutectic grains.
A sharp-interface mesoscopic model for dendritic growth
Authors: Jančič Mitja , Založnik Miha , Kosec Gregor
Published: March 2023

The grain envelope model (GEM) describes the growth of envelopes of dendritic crystal grains during solidification. Numerically the growing envelopes are usually tracked using an interface capturing method employing a phase field equation on a fixed grid. Such an approach describes the envelope as a diffuse interface, which can lead to numerical artefacts that are possibly detrimental. In this work, we present a sharp-interface formulation of the GEM that eliminates such artefacts and can thus track the envelope with high accuracy. The new formulation uses an adaptive meshless discretization method to solve the diffusion in the liquid around the grains. We use the ability of the meshless method to operate on scattered nodes to accurately describe the interface, i.e., the envelope. The proposed algorithm combines parametric surface reconstruction, meshless discretization of parametric surfaces, global solution construction procedure and partial differential operator approximation using monomials as basis functions. The approach is demonstrated on a two-dimensional h-adaptive solution of diffusive growth of dendrites and assessed by comparison to a conventional diffuse-interface fixed-grid GEM.
The macrosegregation behaviour of Fe-C-Cr-Mo type steel in laboratory scale model ingot.
Authors: Sumi Y , Narita S , Yamashita M
Published: March 2023

In ingot casting, it is important to predict and control segregation and casting defects that occur during the solidification process, because they have a significant effect on the quality of the steel ingot. In some special steels, in typical Fe-C-Cr-Mo type high carbon tool steels, macro-segregation tends to be more pronounced due to their wide solid-liquid coexistence temperature range and molten steel properties such as relatively higher liquid viscosity than basic carbon steels. In order to investigate segregation and defect formation phenomena during solidification, many experiments have been conducted using specially designed laboratory scale model ingots that can induce partial difference of solidification to cause macrosegregation phenomena. However, these kind of experimental approaches for special steels are less conducted and influence of alloy types on the macrosegregation behaviour is still not well understood. In this study, a model ingot which have a steel chill ring in the middle region of a mullite mold was prepared, then Fe-0.45C(mass%) carbon steel, Fe-1C-1.8Cr(mass%) bearing steel and Fe-1C-8Cr-2Mo(mass%) high carbon tool steel were cast into 30kg ingots and the macrosegregation behaviour was investigated.
Effect of Zn addition and natural aging on the microstructure and mechanical properties of secondary AlSi7Cu2 alloys
Authors: Scampone G , Gursoy O , Brutti S , Timelli G
Published: March 2023

The effect of different Zn contents on the microstructure of a secondary AlSi7Cu2 alloy has been studied. The mechanical properties of the alloy during natural aging has been investigated too. The Zn additions range from 0.7 to 8 wt.%, and the tensile testing has been carried out at the as-cast condition and after 3, 7, 12 and 21 days of natural aging. Metallographic and image analysis techniques have been used to characterize the microstructural changes of the alloy. The results indicate that the alloy is strengthened as a function of the aging time and Zn addition. Both yield stress and elongation to fracture tend to stabilize over long aging times, independently of Zn level. The steady-state tensile properties are achieved earlier by increasing the Zn content. Furthermore, high Zn contents promote the formation of eutectic structure and the precipitation of needle-like Fe-rich compounds, which decrease the ductility of the material.
List of problems on discrete subgroups of Lie groups and their computational aspects
Authors: Kapovich Michael , Detinko Alla , Kontorovich Alex
Published: March 2023

In this paper we present a problem list pertaining to discrete subgroups of Lie groups and their computational aspects, consisting mostly of the problems collected during the ICERM workshop “Computational Aspects of Discrete Subgroups of Lie Groups” held in June of 2021.
Bounds for exit times of Brownian motion and the first Dirichlet eigenvalue for the Laplacian
Authors: Bañuelos Rodrigo , Mariano Phanuel , Wang Jing
Published: March 2023

For domains in

R

d

\mathbb {R}^d

,

d
≥
2

d\geq 2

, we prove universal upper and lower bounds on the product of the bottom of the spectrum for the Laplacian to the power

p
>
0

p>0

and the supremum over all starting points of the

p
p

-moments of the exit time of Brownian motion. It is shown that the lower bound is sharp for integer values of

p
p

and that for

p
≥
1

p \geq 1

, the upper bound is asymptotically sharp as

d
→
∞

d\to \infty

. For all

p
>
0

p>0

, we prove the existence of an extremal domain among the class of domains that are convex and symmetric with respect to all coordinate axes. For this class of domains we conjecture that the cube is extremal.
ATM–dependent phosphorylation of CHD7 regulates morphogenesis-coupled DSB stress response in fetal radiation exposure
Authors: Noda Asao , Muramoto Kaori , Mishima Shuji
Published: March 2023

While determining the key factors that characterize cells bearing unrepaired double-strand breaks (DSBs), we discovered ATM-dependent phosphorylation of CHD7 at unrepaired DSBs. CHD7 is known to be an indispensable transcription factor in early development. This indicates that morphogenesis and DSB repair are coupled in the development of heart and neurosensory organs.
Retrospective, Observational Studies for Estimating Vaccine Effects on the Secondary Attack Rate of SARS-CoV-2
Authors: Bannick Marlena S , Gao Fei , Brown Elizabeth R , Janes Holly E
Published: March 2023

Coronavirus disease 2019 (COVID-19) vaccines are highly efficacious at preventing symptomatic infection, severe disease, and death. Most of the evidence that COVID-19 vaccines also reduce transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is based on retrospective, observational studies. Specifically, an increasing number of studies are evaluating vaccine effectiveness against the secondary attack rate of SARS-CoV-2 using data available in existing health-care databases or contact-tracing databases. Since these types of databases were designed for clinical diagnosis or management of COVID-19, they are limited in their ability to provide accurate information on infection, infection timing, and transmission events. We highlight challenges with using existing databases to identify transmission units and confirm potential SARS-CoV-2 transmission events. We discuss the impact of common diagnostic testing strategies, including event-prompted and infrequent testing, and illustrate their potential biases in estimating vaccine effectiveness against the secondary attack rate of SARS-CoV-2. We articulate the need for prospective observational studies of vaccine effectiveness against the SARS-CoV-2 secondary attack rate, and we provide design and reporting considerations for studies using retrospective databases.
Choosing Spanish arbitration law to apply the group of companies doctrine
Authors: Mirambell Fargas Miquel
Published: March 2023

This note revisits the status of the Group of Companies doctrine’s application under Spanish arbitration law. It starts with analysing the judgments in ThyssenKrupp AG et al. v Ros Casares Group to develop further questions yet left unresolved. Particularly, what is the scope of extending the effects of an international arbitration agreement and what is the state of party autonomy in regulating the application of the GoC-doctrine, for example, by expressly choosing the applicable law thereto. The latter will determine both the legal standard required to establish implied consent as well as the margin of discretion of decision-makers.
Opposite-sex associations are linked with annual fitness, but sociality is stable over lifetime
Authors: Dunning Jamie , Burke Terry , Hoi Hang Chan Alex , Ying Janet Chik Heung , Evans Tim , Schroeder Julia
Published: March 2023

Animal sociality, an individual’s propensity to associate with others, has fitness consequences through mate choice, for example, directly, by increasing the pool of prospective partners, and indirectly through increased survival, and individuals benefit from both. Annually, fitness consequences are realized through increased mating success and subsequent fecundity. However, it remains unknown whether these consequences translate to lifetime fitness. Here, we quantified social associations and their link to fitness annually and over lifetime, using a multi-generational, genetic pedigree. We used social network analysis to calculate variables representing different aspects of an individual’s sociality. Sociality showed high within-individual repeatability. We found that birds with more opposite-sex associates had higher annual fitness than those with fewer, but this did not translate to lifetime fitness. Instead, for lifetime fitness, we found evidence for stabilizing selection on opposite-sex sociality, and sociality in general, suggesting that reported benefits are only short-lived in a wild population, and that selection favors an average sociality.
Defining the phenotypic spectrum of sporadic Creutzfeldt–Jakob disease MV2K: the kuru plaque type
Authors: Baiardi Simone , Mammana Angela , Dellavalle Sofia , Rossi Marcello , Redaelli Veronica , Colaizzo Elisa , Di Fede Giuseppe , Ladogana Anna , Capellari Sabina , Parchi Piero
Published: March 2023

The current classification of sporadic Creutzfeldt–Jakob disease identifies six major subtypes mainly defined by the combination of the genotype at polymorphic codon 129 (methionine/M or valine/V) of the prion protein gene and the type (1 or 2) of misfolded prion protein accumulating in the brain (e.g. MM1, MM2, MV1, MV2, etc.).

Here, we systematically characterized the clinical and histo-molecular features associated with the third prevalent subtype, the MV2 subtype with kuru plaques (MV2K), in the most extensive series collected to date. We evaluated neurological histories, cerebrospinal biomarkers, brain MRI and EEG results in 126 patients. The histo-molecular assessment included misfolded prion protein typing, standard histologic staining and immunohistochemistry for prion protein in several brain areas. We also investigated the prevalence and topographic extent of coexisting MV2-cortical features, the number of cerebellar kuru plaques and their effect on clinical phenotype.

Systematic regional typing revealed a western blot profile of misfolded prion protein comprising a doublet of 19 and 20 kDa unglycosylated fragments, with the former more prominent in neocortices and the latter in the deep grey nuclei. The 20/19 kDa fragment ratio positively correlated with the number of cerebellar kuru plaques. The mean disease duration was exceedingly longer than in the typical MM1 subtype (18.0 versus 3.4 months). Disease duration correlated positively with the severity of pathologic change and the number of cerebellar kuru plaques. At the onset and early stages, patients manifested prominent, often mixed, cerebellar symptoms and memory loss, variably associated with behavioural/psychiatric and sleep disturbances. The cerebrospinal fluid prion real-time quaking-induced conversion assay was positive in 97.3% of cases, while 14-3-3 protein and total-tau positive tests were 52.6 and 75.9%. Brain diffusion-weighted MRI showed hyperintensity of the striatum, cerebral cortex and thalamus in 81.4, 49.3 and 33.8% of cases, and a typical profile in 92.2%. Mixed histotypes (MV2K + MV2-cortical) showed an abnormal cortical signal more frequently than the pure MV2K (64.7 versus 16.7%, P = 0.007). EEG revealed periodic sharp-wave complexes in only 8.7% of participants.

These results further establish MV2K as the most common ‘atypical’ subtype of sporadic Creutzfeldt–Jakob disease, showing a clinical course that often challenges the early diagnosis. The plaque-type aggregation of the misfolded prion protein accounts for most of the atypical clinical features. Nonetheless, our data strongly suggest that the consistent use of the real-time quaking-induced conversion assay and brain diffusion-weighted MRI allows an accurate early clinical diagnosis in most patients.
Relationship between the interlimb transfer of a visuomotor learning task and interhemispheric inhibition in healthy humans
Authors: Paparella Giulia , De Riggi Martina , Cannavacciuolo Antonio , Colella Donato , Costa Davide , Birreci Daniele , Passaretti Massimiliano , Angelini Luca , Guerra Andrea , Berardelli Alfredo , Bologna Matteo
Published: March 2023

The “interlimb transfer” phenomenon consists of improved performance of the trained and untrained contralateral limbs after unilateral motor practice. We here assessed whether a visuomotor learning task can be transferred from one hemisphere to the other, whether this occurs symmetrically, and the cortical neurophysiological correlates of this phenomenon, focusing on interhemispheric connectivity measures. We enrolled 33 healthy subjects (age range: 24–73 years). Participants underwent two randomized sessions, which investigated the transfer from the dominant to the nondominant hand and vice versa. Measures of cortical and intracortical excitability and interhemispheric inhibition were assessed through transcranial magnetic stimulation before and after a visuomotor task. The execution of the visuomotor task led to an improvement in motor performance with the dominant and nondominant hands and induced a decrease in intracortical inhibition in the trained hemisphere. Participants were also able to transfer the visuomotor learned skill. The interlimb transfer, however, only occurred from the dominant to the nondominant hand and positively correlated with individual learning-related changes in interhemispheric inhibition. We here demonstrated that the “interlimb transfer” of a visuomotor task occurs asymmetrically and relates to the modulation of specific inhibitory interhemispheric connections. The study results have pathophysiological, clinical, and neuro-rehabilitative implications.
Chronic Active Epstein-Barr Virus (EBV) Infection Controlled by Allogeneic Stem Cell Transplantation and EBV-Specific T Cells
Authors: Meedt Elisabeth , Weber Daniela , Bonifacius Agnes , Eiz-Vesper Britta , Maecker-Kolhoff Britta , Delecluse Susanne , Delecluse Henri-Jacques , Lorenz Myriam , Schwarz Klaus , Meedt Stefan T , Braess Jan , Herr Wolfgang , Holler Ernst , Edinger Matthias , Wolff Daniel
Published: March 2023

We report sustained remission of chronic active Epstein-Barr virus (EBV) infection in a 27-year-old female patient treated with third-party EBV-specific T cells followed by allogeneic hematopoietic stem cell transplantation (HSCT). The viremia cleared after administration of anti-T-lymphocyte globulin for graft-versus-host disease (GvHD) prophylaxis. Subsequent expansion of EBV-infected host T cells was controlled by transfusion of donor-derived EBV-specific T cells.
Near Real-Time Social Distance Estimation In London
Authors: Walsh James , Kesa Oluwafunmilola , Wang Andrew , Ilas Mihai , O’Hara Patrick , Giles Oscar , Dhir Neil , Girolami Mark , Damoulas Theodoros
Published: March 2023

To mitigate the current COVID-19 pandemic, policy makers at the Greater London Authority, the regional governance body of London, UK, are reliant upon prompt, accurate and actionable estimations of lockdown and social distancing policy adherence. Transport for London, the local transportation department, reports they implemented over 700 interventions such as greater signage and expansion of pedestrian zoning at the height of the pandemic’s first wave with our platform providing key data for those decisions. Large well-defined heterogeneous compositions of pedestrian footfall and physical proximity are difficult to acquire, yet necessary to monitor city-wide activity (busyness) and consequently discern actionable policy decisions. To meet this challenge, we leverage our existing large-scale data processing urban air quality machine learning infrastructure to process over 900 camera feeds in near real-time to generate new estimates of social distancing adherence, group detection and camera stability. In this work, we describe our development and deployment of a computer vision and machine learning pipeline. It provides near immediate sampling and contextualization of activity and physical distancing on the streets of London via live traffic camera feeds. We introduce a platform for inspecting, calibrating and improving upon existing methods, describe the active deployment on real-time feeds and provide analysis over an 18 month period.
Providing an Approach for Early Prediction of Fall in Human Activities Based on Wearable Sensor Data and the Use of Deep Learning Algorithms
Authors: Keramati Hatkeposhti Rahman , Yadollahzadeh-Tabari Meisam , Golsorkhtabariamiri Mehdi
Published: March 2023

Falling is one of the major health concerns, and its early detection is very important. The goal of this study is an early prediction of impending falls using wearable sensors data. The SisFall data set has been used along with two deep learning models (CNN and a combination model named Conv_Lstm). Also, a dynamic sampling method is offered to improve the accuracy of the models by increasing the equilibrium rate between the samples of the majority and minority classes. To fulfill the main idea of this paper, we present a future prediction strategy. Then, by defining a time variable ‘T’, the system replaces and labels the state of the next T s instead of considering the current state only. This leads to predicting falling states at the beginning moments of balance disturbance. The results of the experiments show that the Conv_Lstm model was able to predict the fall in 78% of cases and an average of 340 ms before the accident. Also, for the Sensitivity criterion, a value of 95.18% has been obtained. A post-processing module based on the median filter was implemented, which could increase the accuracy of predictions to 95%.
Cooperation and the Organisation of Production and Markets: A Critical Survey
Authors: Konzelmann Suzanne J
Published: March 2023

This critical survey examines the role of cooperation in production and exchange, the relationship between the organisation of production and markets, and, more generally, the nature and functioning of productive systems. It traces ideas about the relationship between markets, industrial organisation, and power, from Adam Smith and Karl Marx to the early neo-classical economists, before turning to the evolution of liberal economic thinking that accompanied the emergence and growth of large organisations with market power. This is then confronted with Alfred Marshall’s methodological and theoretical contributions to both economics and industrial organisation and development, and his attempt to reconcile the neo-classical economic dilemma of increasing returns in production and competition in markets. During the inter-war years, and especially after his death in 1924, Marshall’s ideas were strongly challenged—and ultimately abandoned—by neo-classical economists. However, this debate re-emerged nearly a half century later, when the Fordist mass production model faced growing competition from more cooperative forms of industrial organisation. Based on solid empirical research into contemporary industrial districts and localised productive systems, there was a re-discovery of the importance of cooperation in production, and an acknowledgement of the significance of Marshall’s earlier contributions. Inspired by these developments, Frank Wilkinson’s ‘productive systems’ approach brings together the threads running through Smith’s, Marx’s, and Marshall’s analysis of the dynamics of cooperation in production and exchange, to explore the implications of the mutual and conflicting interests inherent to production, industrial organisation, and economic development.