bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of heat transfer processes during selective and while body Newborn’s therapeutic hypotermia – case report
Authors: D. Bandoła , Z. Ostrowski , M. Rojczyk , D. Wagstyl , J. Tumidajski , M. Bojdoł , W. Walas , Z. Halaba , A.J. Nowak 
Published: April 2022

Abstract
In this paper selected heat transfer issues related to the therapeutic hypothermia of newborns are presented and discussed. The therapeutic hypothermia is currently the only well established treatment of newborns suffering for perinatal asphyxia (PA). Considered heat transfer issues are closely associated with the non-invasive thermal measurements carried out at the Department of Anaesthesiology and Intensive Therapy of Children and Newborns of the University Clinic Hospital in Opole, Poland. Obtained results allow for preliminary comparison of the heat transfer processes occurring during both types of therapeutic hypothermia.
Glass beads retro-reflective coating for building application: albedo assessment in urban canyon configurations
Authors: Cardinali Marta , Giuseppe Alessia Di , Gambelli Alberto Maria , Filipponi Mirko , Castellani Beatrice , Nicolini Andrea , Rossi Federico 
Published: April 2022

Abstract
Materials for urban pavements and building coatings have a direct impact on urban thermal environment: low-reflective and highly absorptive materials, in fact, could contribute to the exacerbation of the Urban Heat Island (UHI) phenomenon, which negatively affects building energy consumptions and indoor and outdoor thermal comfort. These effects could be worsened especially in Urban Heat Canyon configurations, where the inter-building effect becomes more relevant. As regards UHI mitigation strategies, high-reflective (HR) and retro- reflective (RR) materials have been studied for their application as urban coatings, in order to provide a cooling effect inside urban canyons. In this framework, this study aims at comparing the albedo performance of HR and RR materials applied on a small scale urban canyon facility. To this aim, an in-field experimental campaign was conducted in two days during summer 2020. Different canyon coating combinations and height/width (H/W) ratios were investigated and compared in terms of albedo. Results show that an albedo worsening occurs when the RR coating was applied to the canyon’s surfaces, because of the lower global reflectance of the RR with respect to the HR. Nevertheless, the application of RR coating on walls, coupled with HR paint on pavement, lead to higher albedo values of up to 4.7%, with respect to the opposite mixed coating combination. Future developments may concern the investigation of the optimum design of a glass bead RR material for building application, by studying the correlation between its optical capabilities and the dimensions and density of the glass beads.
Effect of Different Cooling Methods on Thermal Performance of Single Loop Pulsating Heat Pipe
Authors: Iwata N , Bozzoli F , Cattani L , Pagliarini L , Vocale P 
Published: April 2022

Abstract
A pulsating heat pipe (PHP) is a promising two-phase passive thermal device that consists of a capillary tube meandering between an evaporator and a condenser. Heat is transferred from the evaporator to the condenser by the self-excited oscillation of vapor and liquid. The complete knowledge of the heat transport mechanisms, particularly at the operating limit of PHPs, is far from satisfactory. In PHP, the phase-change acts as a driving force of the self-excited oscillation of the fluid. In this context, the condensation highly affects the performance of PHPs, while few studies have investigated the effect of the sink temperature or the cooling methods. In this study, a single metallic loop is tested to understand the local phenomena focusing on the impact of cooling methods of the condenser section: natural convection and forced air convection. Regardless of the cooling methods, the PHP showed the intermittent and unstable oscillation at low power input just after the start-up, and then continued to operate stably until the heater turned off after the evaporator temperature exceeds 140 °C. The resistance of natural convection cooling is more than 1 K/W lower than that of forced convection cooling, for the same heat input conditions. However, the resistance of both cooling methods at the same evaporator temperature shows a good agreement. The resistance is inversely proportional to the evaporator temperature as well as the heat input.
Study on the local heat transfer behaviour in a flat plate pulsating heat pipe
Authors: Pagliarini Luca , Cattani Luca , Bozzoli Fabio , Slobodeniuk Maksym , Ayel Vincent , Romestant Cyril , Bertin Yves , Rainieria Sara 
Published: April 2022

Abstract
A closed-loop Flat Plate Pulsating Heat Pipe, filled with a water-ethanol mixture (filling ratio = 50% vol.), is tested in horizontal orientation at different heat loads to assess local wall-to-fluid heat fluxes exchanged within its adiabatic section. In addition, the thermal interactions between adjacent channels are investigated since they could be responsible for poorer thermal performances in such kinds of cooling systems. The studied device is obtained from a copper plate (width: 80 mm, length: 200 mm, thickness: 3.5 mm) machined with a single square shaped groove (3 x 3 mm2) forming a series of 8 turns in the evaporator zone and covered with a second copper plate having same length and width, and thickness equal to 0.5 mm. During the Flat Plate Pulsating Heat Pipe operation, the temperature of the external wall, coated with a high-emissivity paint, is monitored within the whole adiabatic section by an InfraRed camera during the pseudo-steady state. The thermographic measurements are post-processed by adopting the Inverse Heat Conduction Problem resolution approach, adequately validated by numerical simulations. The resulting wall-to-fluid heat fluxes are studied in terms of amplitude and oscillation, thus providing novel pieces of information regarding the working behaviour of Flat Plate Pulsating Heat Pipes in terms of oscillatory flow and thermal interactions by conduction between adjacent channels.
Performance Evaluation Criteria for Triangular Microchannels with Smoothed Corners
Authors: Suzzi Nicola , Lorenzini Marco 
Published: April 2022

Abstract
The manufacturing capabilities available today for microchannels make it possible to produce in a comparatively easy, quick and cheap way several cross-sections, possibly allowing modifications of the macro-geometry. Another way is smoothing the corners of polygona cross-sections: this eliminates low-gradient areas and increases transport phenomena, i.e. frictional losses and heat transfer. Several ways of assessing the relative performance of the new shape in comparison to the original have been suggested over the years, among which are Performance Evaluation Criteria (PEC), as proposed by Bergles and Webb. PEC are based on a first-law analysis and aim at extremising the thermal power, heat exchange area, inlet temperature difference or pumping power under varying constraints. In this work equilateral triangular microchannels with uniform wall temperature are considered, through which a liquid flows in fully-developed, steady laminar regime. The cross-sectional area has its corners progressively rounded, and the velocity and temperature profiles are determined, in order to compute the Poiseuille, Nusselt and Stanton numbers, which are then employed in computing the objective functions for some PEC.
Numerical modelization of contact angle hysteresis of falling droplet under enhanced lubrication approximation
Authors: Suzzi Nicola , Croce Giulio 
Published: April 2022

Abstract
Moving contact lines are involved in several engineering applications: in in-flight icing phenomenon, the eventual transition from droplet to rivulet or continuous film regime is crucial for the prediction of ice accretion over the aircraft surface; absorption process through structured packing is also characterized by a thin film flowing over the corrugated sheets. Disjoining pressure together with the assumption of a thin precursor film is largely used in numerical simulations of thin films and moving droplets in order to model the dynamics of moving contact lines and the surface wettability properties, in terms of imposed static contact angle. The disjoining pressure model was largely validated in case of falling films with the well known Voinov-Hoffman-Tanner law. On the other side, the capability of the disjoining pressure to model the contact angle hysteresis, which is a crucial parameter for predicting moving droplets behavior, has not been discussed yet. Here, numerical simulations of both falling films and moving droplets under lubrication approximation are conducted and the disjoining pressure model is used to predict the contact line dynamics. After verification of the full curvature implementation for a 1D falling film, the effective contact angle hysteresis is estimated for a moving droplet under different flow conditions and the transition from droplet to rivulet regime detected.
SRS-based Timepix3 readout system
Authors: Gruber M. , Desch K. , Hemperek T. , Kaminski J. , Richarz L. , Schiffer T. 
Published: April 2022

Abstract
With the combination of the highly granular pixel ASIC Timepix3 by the Medipix3 collaboration and several technologies we are developing a range of detectors. These technologies are bump bonded sensors, microchannel plates (MCP) and photolithographically postprocessed gas amplification stages (InGrid). For example, we are using the combination of the ASIC and an InGrid for the development of X-ray detectors for X-ray polarimetry and for axion search at IAXO. Based on the combination of the ASIC and silicon sensors we are developing a tracker or respectively a beam telescope. The combination of the ASIC and a microchannel plate will be used for neutron detectors. As this range of detectors has several requirements towards the readout and control system and a wide range of designs from low- to high-rate (Hz to MHz) and from single- to multichip, a versatile readout system is needed which adapts these applications without producing too much overhead for the others. To fulfil these requirements, we are developing a modular and scalable readout and control system based on the basil framework — a modular data acquisition system and system testing framework. The fully open-source implementation uses Verilog for the firmware and Python for the software. The system supports several FPGA boards to offer different applications a range of capabilities. One of these FPGA boards is the Scalable Readout System (SRS) by RD51 which offers scalability in low to medium rate applications. For high-rate applications we are working towards the firmware implementation on Xilinx adaptive compute acceleration platform. Besides the scalability, the system offers an optional monitoring interface via a microcontroller for monitoring chip temperatures and power supply voltages. Additionally, further external sensors could be connected to the monitoring system for example via I2C or SPI. For controlling the full system, the software offers a command line interface and a graphical user interface. Both interfaces also include an online event display to monitor the raw data. Additional meta data and data of the monitoring system is stored in a database and can be visualised with a monitoring dashboard.
High-spatial resolution measurements with a GaAs:Cr sensor using the charge integrating MÖNCH detector with a pixel pitch of 25 μm
Authors: Chiriotti S. , Barten R. , Bergamaschi A. , Brückner M. , Carulla M. , Chsherbakov I. , Dinapoli R. , Fröjdh E. , Greiffenberg D. , Hasanaj S. , Hinger V. , King T. , Kozlowski P. , Lopez-Cuenca C. , Lozinskaya A. , Marone F. , Mezza D. , Moustakas K. , Mozzanica A. , Ruder C. , Schmitt B. , Thattil D. , Tolbanov O. , Tyazhev A. , Zarubin A. , Zhang J. 
Published: April 2022

Abstract
The aim of this project is to determine the imaging
capabilities of a 25 μm pixel pitch GaAs:Cr sensor of
500 μm thickness bump-bonded to the charge integrating
MÖNCH 03 readout chip (also called GaAs-MÖNCH assembly) and to
assess the possibility to improve the spatial resolution by applying
a position interpolation algorithm developed at PSI.

Measurements were performed at the TOMCAT beamline of the Swiss
Light Source (SLS) using photon beams in the energy range of
10–30 keV. The imaging experiments indicate the possibility to
enhance the spatial resolution of the detector beyond its actual
physical pixel pitch. We have quantified the spatial resolution of a
GaAs-MÖNCH assembly by means of the modulation transfer function
(MTF), achieving 10 μm at 10 keV and 12 μm at 20 keV
photon energies. By applying a modified interpolation algorithm, a
spatial resolution of ∼5 μm was obtained for 16 keV
when binning to 2.5 μm virtual pixels, while with the
silicon-MÖNCH assembly, we achieved a spatial resolution of
3.5 μm, which serves as gold standard.

The results are promising because they open new possibilities to
perform imaging measurements using the GaAs-MÖNCH assembly at
photon energies above 15 keV, where silicon sensors suffer from a
diminishing quantum efficiency.
Registration of a pulsed generation of electron beam in the nanosecond range under heating and cooling cycles of a lithium niobate crystal at atmospheric pressure
Authors: Mambetova K.M. , Shandarov S.M. , Arestov S.I. , Orlikov L.N. , Elchaninov A.A. , Burimov N.I. , Aksenov A.I. 
Published: April 2022

Abstract
We describe here an experimental prototype designed for
registration of nanosecond discharge current pulses with an
amplitude of up to 600 mA and a negative/positive polarity in the
air gap between the +Z surface of a pyroelectric lithium niobate
crystal and a flat copper electrode during the crystal
heating/cooling cycles. The experiments were carried out in air at
atmospheric pressure using a cylindrical lithium niobate sample with
a diameter of 13 mm and a thickness of 7 mm. With the temperature
varying from 20 to 80 °C, there were registered over 50
discharge pulses for heating as well as for cooling stage. Their
parameters testify to pyroelectric generation of pulsed electron
beam with a current at maximum from 45 mA to 600 mA, duration of
about 15 ns, rise time from 1 to 1.9 ns, and transferred charge
from 0.95 to 5.7 nC.
Experimental and theoretical study on enhanced electrochemistry of aluminum substitution LLZO garnet solid electrolytes
Authors: Liu Junlong , Zhang Jiatong , You Ruoshui , Chen Daming , Li Yuanxun , Lu Yongcheng , Yang Qinghui 
Published: April 2022

Abstract
Although the wider electrochemical window, higher temperature stability, and better battery safety of Li7La3Zr2O12 (LLZO) electrolytes than organic liquid, organogels, and polyelectrolytes, the limited ionic conductivity still far away from the practical electrochemical applications. Herein, LLZO electrolytes were by solid phase method. In order to further improve its electrochemical performance, aluminum substitution was introduced to replace Li+ sites and thus the highly conductive cubic phase was stabilized. The results show that with the increase of the substitution amount, the ion conductivity presents a trend of first increasing and then decreasing. It was found that 0.15Al-LLZO ceramics presented optimized ionic conductivity (1.184 × 10–4 S·cm−1) and 92.5% of bulk density at 1150 °C for 21 h treatment. On the other hand, with the combination of molecular simulations, the relationship between the influence of aluminum substitution on the differential charge density of the garnet solid electrolyte and the electrochemical performance was investigated. It is believed that such an experimental-modeling combination will expand the fundamental understanding of elements variation/substitution effects on solid electrolytes, especially for lithium metal oxides.
Austenitization and formation of ausferrite structure in austempered ductile iron with dual matrix
Authors: Tuan Hoang Anh , Hai Nguyen Hong , Dung Nguyen Huu , Nam Tran The , Nam Nguyen Duong 
Published: April 2022

Abstract
The effect of austenitizing conditions on the microstructure and mechanical properties of an austempered ductile iron (ADI) with a dual matrix was investigated. Carbon diffusion plays a critical role in the phase transformation of austenitization. In initially pearlitic structures, the carbon diffusion distances involved during austenitization are smaller compared to those in ferritic structures. The study was carried out to examine the influence of temperature and times of the austenitization process on the maximum carbon content in austenite and then its effect on the processing window of ADI with the dual matrix. An alloyed ductile iron (3,6%C; 2,44%Si; 0,36%Mn; 0,9%Ni; 0,61%Cu; 0,11%Cr; 0,036%Mg; 0,015%S và 0,006%P) was fully austenitic at various temperatures 870 °C–930 °C. The minimum hardness reaches the value of 270 HB. An increase in austenitization temperature increases the carbon content dissolved in the austenite, which in turn, decreases the free energy controlling the transformation of austenite to bainite ferrite and high carbon austenite. Raising the austenitization temperature makes the process window shift toward the extending time. The carbon atoms must diffuse out of the ferrite needle with a diffusion distance equal to the ferrite layer thickness. At 360 °C austempered temperature, diffusion coefficient D = 4.60.10–17(m2/s). With a ferrite needle thickness of 1μm = 10–6 m, the diffusion time would be t = 5330 (s).
A fractal version of the Onsager’s conjecture: The 𝛽-model
Authors: De Rosa Luigi , Haffter Silja 
Published: April 2022

Intermittency phenomena are known to be among the main reasons why Kolmogorov’s theory of fully developed Turbulence is not in accordance with several experimental results. This is why some fractal statistical models have been proposed in order to realign the theoretical physical predictions with the empirical experiments. They indicate that energy dissipation, and thus singularities, is not space filling for high Reynolds numbers. This note aims to give a precise mathematical statement on the energy conservation of such fractal models of Turbulence. We prove that for

θ
−

\theta -

Hölder continuous weak solutions of the incompressible Euler equations energy conservation holds if the upper Minkowski dimension of the spatial singular set

S
⊆

T

3

S \subseteq \mathbb {T}^3

(possibly also time-dependent) is small, or more precisely if

dim
¯

M

(
S
)
>
2
+
3
θ

\overline {\operatorname {dim}}_{\mathcal {M}}(S)>2+3\theta

. In particular, the spatial singularities of non-conservative

θ
−

\theta -

Hölder continuous weak solutions of Euler are concentrated on a set with dimension lower bound

2
+
3
θ

2+3\theta

. This result can be viewed as the fractal counterpart of the celebrated Onsager conjecture and it matches both with the prediction given by the

β
−

\beta -

model introduced by Frisch, Sulem and Nelkin [J. Fluid Mech. 87 (1978), pp. 719–736] and with other mathematical results in the endpoint cases.
On the number of generators of an algebra over a commutative ring
Authors: First Uriya , Reichstein Zinovy , Williams Ben 
Published: April 2022

A theorem of O. Forster says that if

R
R

is a noetherian ring of Krull dimension

d
d

, then every projective

R
R

-module of rank

n
n

can be generated by

d
+
n

d+n

elements. S. Chase and R. Swan subsequently showed that this bound is sharp: there exist examples that cannot be generated by fewer than

d
+
n

d+n

elements. We view rank-

n
n

projective

R
R

-modules as

R
R

-forms of the non-unital

R
R

-algebra

R
n

R^n

where the product of any two elements is

0
0

. The first two authors generalized Forster’s theorem to forms of other algebras (not necessarily commutative, associative or unital); A. Shukla and the third author then showed that this generalized Forster bound is optimal for finite étale algebras.

In this paper, we prove new upper and lower bounds on the number of generators of an

R
R

-form of a

k
k

-algebra, where

k
k

is an infinite field and

R
R

is a finitely generated

k
k

-ring of Krull dimension

d
d

. In particular, we show that, contrary to expectations, for most types of algebras, the generalized Forster bound is far from optimal. Our results are particularly detailed in the case of Azumaya algebras. Our proofs are based on reinterpreting the problem as a question about approximating the classifying stack

B
G

BG

, where

G
G

is the automorphism group of the algebra in question, by algebraic spaces of a certain type.
CFD analysis for mixing performance of different types of household biodigesters
Authors: Shrestha Sagar , Lohani Sunil Prasad 
Published: April 2022

Abstract
Household biodigesters are self-mixing anaerobic digesters used mostly in rural areas of developing countries as a reliable source of clean cooking energy. For an efficient anaerobic digestion process, the mixing of slurry inside the digester is regarded as one of the most important parameters. In this study, the mixing of slurry in three different designs of household digesters, namely the fixed-dome digester (GGC 2047 model), plug-flow digester and prefabricated plastic digester, are investigated and compared using computational fluid dynamics. A 3D transient simulation is performed using a multiphase volume of fluid (VOF) model in Ansys® Fluent release 16.0. The rheological properties of the feedstock are considered identical for all three digesters. The volume of the plug-flow and prefabricated plastic digesters is designed to be 1 m3 while the volume of the GGC 2047 digester was 6 m3 as the standard size of the household digester. The regions inside the digester where the velocity of slurry is &lt;0.02 m/s are regarded as dead zones and the obtained results were analysed and compared using velocity patterns and dead-zone formation. It is found that the prefabricated plastic digester model has a relatively higher percentage of dead volume (74.6%) and the plug-flow digester has the lowest percentage (54%) of dead volume among digesters that were compared in this study. The study will serve as the basis for designers and researchers to improve the design of household digesters for better mixing performances.