bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple descriptor for magnetic classification of 2D MXene materials
Authors: Song Yi-Yan , Wu Xu-Cai , Li Shu-Zong , Sun Qingde , Zhang Wei-Bing
Published: July 2022

Classification of the magnetic state is an essential step to investigate two-dimensional magnetic materials. Combining high-throughput calculations and machine-learning methods, we have classified the magnetic states of 23 825 MXenes in the aNANt database. A simple descriptor, obtained by averaging the product of the element feature, connectivity, and Coulomb matrix, was found to improve the performance of the machine-learning models. Using this descriptor on 4153 data produced using first-principles calculations, predictive machine-learning models were developed and 1432 MXene with a high saturation magnetization were predicted. The proposed descriptor is useful for the magnetic classification of other materials, and the identified magnetic MXene materials can be used as an important reference for further study.
Broadband stimulated Raman imaging based on multi-channel lock-in detection for spectral histopathology
Authors: De la Cadena Alejandro , Vernuccio Federico , Ragni Andrea , Sciortino Giuseppe , Vanna Renzo , Ferrante Carino , Pediconi Natalia , Valensise Carlo , Genchi Luca , Laptenok Sergey P. , Doni Andrea , Erreni Marco , Scopigno Tullio , Liberale Carlo , Ferrari Giorgio , Sampietro Marco , Cerullo Giulio , Polli Dario
Published: July 2022

Spontaneous Raman microscopy reveals the chemical composition of a sample in a label-free and non-invasive fashion by directly measuring the vibrational spectra of molecules. However, its extremely low cross section prevents its application to fast imaging. Stimulated Raman scattering (SRS) amplifies the signal by several orders of magnitude thanks to the coherent nature of the nonlinear process, thus unlocking high-speed microscopy applications that provide analytical information to elucidate biochemical mechanisms with subcellular resolution. Nevertheless, in its standard implementation, narrowband SRS provides images at only one frequency at a time, which is not sufficient to distinguish constituents with overlapping Raman bands. Here, we report a broadband SRS microscope equipped with a home-built multichannel lock-in amplifier simultaneously measuring the SRS signal at 32 frequencies with integration time down to 44 µs, allowing for detailed, high spatial resolution mapping of spectrally congested samples. We demonstrate the capability of our microscope to differentiate the chemical constituents of heterogeneous samples by measuring the relative concentrations of different fatty acids in cultured hepatocytes at the single lipid droplet level and by differentiating tumor from peritumoral tissue in a preclinical mouse model of fibrosarcoma.
A miniaturized low frequency direct-current magnetic-bias-integrated magnetoelectric wireless power transfer system with enhanced energy conversion efficiency
Authors: Ren Hao , Niu Yunping
Published: July 2022

Wireless power transfer (WPT), which transfers energy without a physical link, has recently received significant research interest. Due to the advantages of small dimension, low operation frequency, and low transmission loss, magnetoelectric WPT (ME-WPT) has been shown to be a promising technology for internet of things (IoT) and implantable medical device (IMD) applications. However, ME-WPT requires a direct-current (DC) magnetic bias for optimal performance and prior arts have implemented large electromagnets, Helmholtz coils, or externally positioned magnet bias systems, which increase the system dimension. Furthermore, the highest energy conversion efficiency (ECE) reported by prior ME-WPT studies is 0.62%, which needs to be improved. In this paper, we present an ME-WPT system with a novel miniaturized ME-WPT receiver and a spiral coil based transmitter. Four DC magnets are integrated onto the ME-WPT receiver to significantly reduce its dimension while providing a DC magnetic bias of 190 Oe for optimal performance. Electrochemical polarization characterizations are introduced to analyze the performance of the WPT receiver, which reveal that a maximum output power of 4.096 mW is obtained. A record ECE of 2.64% is reported, the highest among all ME-WPTs to date. The output power is improved by at least 49.3 times compared with the ME-WPT without integrated DC magnets. The influence of the input voltage and the distance between transmitter/receiver on the performance of the ME-WPT system is studied, which shows that the output power increases as the distance decreases and the input voltage increases. The proposed ME-WPT system with integrated DC magnets has potential applications in IoT and IMDs.
Effect of cross-sectional geometry on the compression fatigue behavior of NiTi refrigerants
Authors: Zhou Guoan , Zhang Lingyun
Published: July 2022

Elastocaloric refrigeration requires refrigerants with a good heat transfer ability and a high fatigue life. A million-level fatigue life can be normally obtained for NiTi refrigerants via compressive loading. However, existing compression-based NiTi elastocaloric prototypes only focus on tube refrigerants, and no research has been reported on the cross-sectional geometry design and its influence on the compression fatigue behavior of NiTi refrigerants. Here, we propose tubular NiTi refrigerants of hole-type, fin-type, and layer-type cross sections and compare their compression fatigue behavior with NiTi tubes of the same cross-sectional area under cyclic loading of 20 Hz and 900 MPa. Results show that to achieve a larger specific heat transfer area (SA), the compression fatigue life of NiTi tubes monotonically decreases because of the decrease in the wall-thickness, while the layer-type NiTi refrigerant maintains a relatively high fatigue life of 1.7 × 106 cycles at a high SA level (3.83 cm2 g−1). This gives us insight into enhancing elastocaloric refrigerants’ heat transfer ability and fatigue life via geometry design.
Potential drivers of common brushtail possum (
Authors: Neilly H. , McKenzie T. , Ward M. , Chaber A. , Cale P.
Published: July 2022

Australia’s terrestrial mammalian fauna have experienced severe declines since European settlement. On the Murray–Darling floodplain in south-eastern Australia, common brushtail possums (Trichosurus vulpecula, ‘possums’), have contracted to riparian zones. Although an important possum refuge, little is known about possum population dynamics here. We examined possum population dynamics and potential drivers across two decades on the Murray River floodplain at Calperum Station. We related possum density to satellite derived fractional cover, (a measure of the proportion of green, non-green and bare ground cover), and contextualised these findings using tree condition and grazing pressure datasets. Possum surveys were conducted between 1998 and 2019 in riparian and non-riparian habitats and density was modelled in relation to fractional cover values of green, non-green, and bare ground. Possum density fluctuated between 1998 and 2008 but in 2018 and 2019, possums were undetectable. Possum density was negatively associated with bare ground and positively associated with non-green. Overgrazing by kangaroos likely reduced vegetation cover and diversity and contributed to possum decline, via a reduction in possum food resources and increased exposure to predation. Inconsistent monitoring meant that the population decline was not detected until after it had occurred, and management interventions were not triggered, highlighting the dilemma of allocating scarce monitoring resources.
How immersion in remote Aboriginal communities influences medical students’ career intentions
Authors: Mitchell Jessica , Rumbelow Jack , Broadley Amy , Sharley Laura , Osti Millicent , Benson Jill
Published: July 2022

The term ‘Aboriginal’ in this text has been used when referring to Aboriginal peoples living on the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands. The term ‘Aboriginal and Torres Strait Islander’ has been used when referring to the broader community. Background This project investigated how cultural immersion in remote Aboriginal communities influenced medical students’ career intentions. Methodology An academic GP registrar (AB) interviewed 15 medical students who participated in the Adelaide Medical Students’ Society Anangu Pitjantjatjara Yankunytjatjara (APY) Exchange. This program was coordinated by medical student volunteers in collaboration with the Ngaanyatjarra Pitjantjatjara Yankunytjatjara Women’s Council (NPYWC). The following questions were specifically addressed: ‘How does being a guest in a remote Aboriginal community influence medical students’ attitudes towards Aboriginal and Torres Strait Islander health care?’ and ‘Does exposure to Aboriginal communities increase medical students’ willingness to pursue careers in Aboriginal and Torres Strait Islander health, rural and remote medicine and/or general practice?’. Results Interest in Aboriginal and Torres Strait Islander health care increased from 73% of participants pre-trip to 100% post-trip, in rural and remote medicine from 40% to 100%, and in general practice from 33% to 67%. The experience also challenged pre-conceptions and increased understanding of the bio-psycho-socio-spiritual aspects of Aboriginal health. Conclusion Being a guest in remote Aboriginal communities enhanced students’ personal and professional motivation to work in Aboriginal and Torres Strait Islander health, remote health and general practice.
A method to predict the response to directional selection using a Kalman filter
Authors: Milocco Lisandro , Salazar-Ciudad Isaac
Published: July 2022

Predicting evolution remains challenging. The field of quantitative genetics provides predictions for the response to directional selection through the breeder’s equation, but these predictions can have errors. The sources of these errors include omission of traits under selection, inaccurate estimates of genetic variance, and nonlinearities in the relationship between genetic and phenotypic variation. Previous research showed that the expected value of these prediction errors is often not zero, so predictions are systematically biased. Here, we propose that this bias, rather than being a nuisance, can be used to improve the predictions. We use this to develop a method to predict evolution, which is built on three key innovations. First, the method predicts change as the breeder’s equation plus a bias term. Second, the method combines information from the breeder’s equation and from the record of past changes in the mean to predict change using a Kalman filter. Third, the parameters of the filter are fitted in each generation using a learning algorithm on the record of past changes. We compare the method to the breeder’s equation in two artificial selection experiments, one using the wing of the fruit fly and another using simulations that include a complex mapping of genotypes to phenotypes. The proposed method outperforms the breeder’s equation, particularly when traits under selection are omitted from the analysis, when data are noisy, and when additive genetic variance is estimated inaccurately or not estimated at all. The proposed method is easy to apply, requiring only the trait means over past generations.
Transforming growth factor-β signaling governs the differentiation program of extravillous trophoblasts in the developing human placenta
Authors: Haider Sandra , Lackner Andreas Ian , Dietrich Bianca , Kunihs Victoria , Haslinger Peter , Meinhardt Gudrun , Maxian Theresa , Saleh Leila , Fiala Christian , Pollheimer Jürgen , Latos Paulina A. , Knöfler Martin
Published: July 2022

Abnormal placentation has been noticed in a variety of pregnancy complications such as miscarriage, early-onset preeclampsia, and fetal growth restriction. Defects in the developmental program of extravillous trophoblasts (EVTs), migrating from placental anchoring villi into the maternal decidua and its vessels, is thought to be an underlying cause. Yet, key regulatory mechanisms controlling commitment and differentiation of the invasive trophoblast lineage remain largely elusive. Herein, comparative gene expression analyses of HLA-G–purified EVTs, isolated from donor-matched placenta, decidua, and trophoblast organoids (TB-ORGs), revealed biological processes and signaling pathways governing EVT development. In particular, bioinformatics analyses and manipulations in different versatile trophoblast cell models unraveled transforming growth factor-β (TGF-β) signaling as a crucial pathway driving differentiation of placental EVTs into decidual EVTs, the latter showing enrichment of a secretory gene signature. Removal of Wingless signaling and subsequent activation of the TGF-β pathway were required for the formation of human leukocyte antigen-G
+
(HLA-G
+
) EVTs in TB-ORGs that resemble in situ EVTs at the level of global gene expression. Accordingly, TGF-β–treated EVTs secreted enzymes, such as DAO and PAPPA2, which were predominantly expressed by decidual EVTs. Their genes were controlled by EVT-specific induction and genomic binding of the TGF-β downstream effector SMAD3. In summary, TGF-β signaling plays a key role in human placental development governing the differentiation program of EVTs.
Structural changes across thermodynamic maxima in supercooled liquid tellurium: A water-like scenario
Authors: Sun Peihao , Monaco Giulio , Zalden Peter , Sokolowski-Tinten Klaus , Antonowicz Jerzy , Sobierajski Ryszard , Kajihara Yukio , Baron Alfred Q. R. , Fuoss Paul , Chuang Andrew Chihpin , Park Jun-Sang , Almer Jonathan , Hastings J. B.
Published: July 2022

Liquid polymorphism is an intriguing phenomenon that has been found in a few single-component systems, the most famous being water. By supercooling liquid Te to more than 130 K below its melting point and performing simultaneous small-angle and wide-angle X-ray scattering measurements, we observe clear maxima in its thermodynamic response functions around 615 K, suggesting the possible existence of liquid polymorphism. A close look at the underlying structural evolution shows the development of intermediate-range order upon cooling, most strongly around the thermodynamic maxima, which we attribute to bond-orientational ordering. The striking similarities between our results and those of water, despite the lack of hydrogen-bonding and tetrahedrality in Te, indicate that water-like anomalies may be a general phenomenon among liquid systems with competing bond- and density-ordering.
Multi-wavelength-tunable thulium-doped fiber laser generation based on dual-pass Mach–Zehnder and Sagnac loop hybrid filters
Authors: Qin Gaolin , Li Quancai , Wei Wei , Duan Junfa
Published: July 2022

A wavelength-tunable thulium-doped fiber laser (TDFL) based on a Mach–Zehnder (MZ) filter and Sagnac loop was proposed in this study. The dual-pass MZ fiber filter, and Sagnac loop were fabricated to operate as reflectors in a linear cavity. The laser operating threshold was set to 138 mW. A single-wavelength laser output with an optical signal-to-noise ratio (OSNR) of up to 38 dB was realized with a tuning range of 1854–1882 nm. The tuning range was obtained with a tuning interval of 6 nm by tuning the polarization controller (PC), which yielded a power shift of less than 0.42 dB. Stability of the single-wavelength center wavelength power fluctuation was less than 0.39 dB within 20 min. When the laser was operated in the dual-wavelength condition, the OSNR was more than 30.5 dB, and the power fluctuation was less than 0.89 dB within 20 min at room temperature. The tunable triple-wavelength laser emission could be realized experimentally by adjusting the PC, which yielded an OSNR of more than 30.8 dB. The proposed TDFL is suitable for fiber-sensing system applications.
Simulation of the multi-beam electron-beam wire-feed additive manufacturing process in a vacuum
Authors: Davlyatshin R P , Gerasimov R M , Bayandin Y V , Saucedo-Zendejo F R , Trushnikov D N
Published: July 2022

The paper considers modelling the wire deposition process with vertically fed wire by several symmetrically acting heat sources. We proposed the mathematical model to describe the above process, considering surface tension force, Marangoni force, vapor pressure force, and heat loss on evaporation. To solve the mathematical model, we use the smoothed particle hydrodynamics method. We carried out a series of numerical experiments for modelling the melting process of vertically fed wire with two symmetrically acting heat sources with different power and direction of action of heat sources. We found that vertical wire feeding provides uniform heating with the absence of shaded areas and flexible control of heat input into the metal. On the other hand, the weld bead geometry characteristics significantly depend on the heat sources’ power and direction.
Influence of the parameters of the heat treatment mode on the structure formation and properties of the welded material for the alloy Ti-Al-V
Authors: Krivonosova E A , Olshanskaya T V , Akulova S N , Myshkina A V , Salomatova E S
Published: July 2022

The article is devoted to a topical problem related to the study of the main regularities of the formation of the structure and properties of the titanium alloy Ti-Al-V of the Ti-Al-V system in additive hybrid production technologies using plasma surfacing. The aim of this work is to study the effect of various types of heat treatment on the physical and mechanical properties of the titanium alloy Ti-Al-V, obtained in the process of 3D printing.
Modeling of heat and mass transfer and electrons scattering in electron beam welding and additive manufacturing
Authors: Shcherbakov A V , Gaponova D A , Gudenko A V , Sliva A P , Rodyakina R V , Goncharov A L , Ovechnikov S A , Dragunov V K
Published: July 2022

The mathematical formulation of electron beam melting and liquid metal transfer model in wire-based additive manufacturing with temperature dependencies of thermophysical properties is described. A description of the model algorithmic implementation based on the use of numerical methods for solving the Navier-Stokes equations system and the Volume of Fluid (VOF) method for tracking the free surface of a liquid on the cubic mesh cells is given. An iterative method for calculating the pressure field that ensures the fulfillment of the incompressibility condition for a viscous fluid is described. The paper also paid attention to the description of methodology for calculating the forces acting on the free surface of the melt, including surface tension forces and metal vapor pressure forces. One of the key elements of the proposed model is method for volumetric distribution of electron losses calculating, considering their scattering during the interaction of an electron beam with a curved melt surface. Electron beam focusing influence on the distribution of energy losses and the dynamics of penetration channel formation has been studied. An algorithm for visualizing the free surface of the melt based on the use of the Gaussian function, is described.
Extrusion 3D printing of keratin protein hydrogels free of exogenous chemical agents
Authors: Brodin Erik , Boehmer Melanie , Prentice Alexandra , Neff Emily , McCoy Kathleen , Mueller Jens , Saul Justin , Sparks Jessica L
Published: July 2022

Keratins are a class of intermediate filament proteins that can be obtained from numerous sources including human hair. Materials fabricated from keratins offer desirable characteristics as scaffolds for tissue engineering, including intrinsic cell adhesion sequences and tunable degradation kinetics. The capacity to create 3D printed constructs from keratin-based bio-inks generates unique opportunities for spatial control of scaffold physicochemical properties to direct scaffold functions in ways not readily achieved through other means. The aim of this study was to leverage the controllable rheological properties of keratin hydrogels to create a strategy for extrusion 3D printing of keratin bio-inks without the use of exogenous rheological modifiers, crosslinking agents, or photocurable resins. The rheological properties of keratin hydrogels were tuned by varying two parameters: (a) the ratio of keratose (obtained by oxidative extraction of keratin) to kerateine (obtained by reductive extraction of keratin); and (b) the weight percentage of total keratin protein in the gel. A computational model of the dispensing nozzle for a commercially available extrusion 3D printer was developed to calculate the needed pneumatic printing pressures based on the known rheological properties of the gels. Keratin hydrogel constructs, of varying keratose/kerateine ratios and total keratin weight percentages, were 3D printed in cylindrical geometries via extrusion 3D printing. Rheology and degradation studies showed that gels with greater relative kerateine content exhibited greater flow resistance and slower degradation kinetics when submerged in phosphate buffered saline solution at 37 °C, owing to the presence of cysteine residues in kerateine and the capability of forming disulfide bonds. Total keratin weight percentage was found to influence gel yield stress, with possible implications for tuning filament fidelity. Findings from this work support the use of keratose/kerateine ratio and total keratin weight percentage as handles for modulating rheological characteristics of keratin hydrogels to enhance printability and control scaffold properties.
Remote sensing-based vegetation and soil moisture constraints reduce irrigation estimation uncertainty
Authors: Nie Wanshu , Kumar Sujay V , Bindlish Rajat , Liu Pang-Wei , Wang Shugong
Published: July 2022

Understanding the human water footprint and its impact on the hydrological cycle is essential to inform water management under climate change. Despite efforts in estimating irrigation water withdrawals in earth system models, uncertainties and discrepancies exist within and across modeling systems conditioned by model structure, irrigation parameterization, and the choice of input datasets. Achieving model reliability could be much more challenging for data-sparse regions, given limited access to ground truth for parameterization and validation. Here, we demonstrate the potential of utilizing remotely sensed vegetation and soil moisture observations in constraining irrigation estimation in the Noah-MP land surface model. Results indicate that the two constraints together can effectively reduce model sensitivity to the choice of irrigation parameterization by 7%–43%. It also improves the characterization of the spatial patterns of irrigation and its impact on evapotranspiration and surface soil moisture by correcting for vegetation conditions and irrigation timing. This study highlights the importance of utilizing remotely sensed soil moisture and vegetation measurements in detecting irrigation signals and correcting for vegetation growth. Integrating the two remote sensing datasets into the model provides an effective and less feature engineered approach to constraining the uncertainty of irrigation modeling. Such strategies can be potentially transferred to other modeling systems and applied to regions across the globe.
Gradient descent dynamics and the jamming transition in infinite dimensions
Authors: Manacorda Alessandro , Zamponi Francesco
Published: July 2022

Gradient descent dynamics in complex energy landscapes, i.e. featuring multiple minima, finds application in many different problems, from soft matter to machine learning. Here, we analyze one of the simplest examples, namely that of soft repulsive particles in the limit of infinite spatial dimensiond. The gradient descent dynamics then displays ajammingtransition: at low density, it reaches zero-energy states in which particles’ overlaps are fully eliminated, while at high density the energy remains finite and overlaps persist. At the transition, the dynamics becomes critical. In thed→ ∞ limit, a set of self-consistent dynamical equations can be derived via mean field theory. We analyze these equations and we present some partial progress towards their solution. We also study the random Lorentz gas in a range ofd= 2…22, and obtain a robust estimate for the jamming transition ind→ ∞. The jamming transition is analogous to the capacity transition in supervised learning, and in the appendix we discuss this analogy in the case of a simple one-layer fully-connected perceptron.
Fully linear band crossings at high symmetry points in layers: classification and role of spin–orbit coupling and time reversal
Authors: Lazić N , Damljanović V , Damnjanović M
Published: July 2022

Symmetry imposed restrictions to the Hamiltonian are systematized and applied to all of 80 clusters of single/double ordinary/gray groups (320 groups in total), to single out linear (in all directions) band crossings and corresponding effective Hamiltonians in high-symmetry Brillouin zone points of layered materials. The resulting dispersion types are isotropic or anisotropic forms of: single cone (with double degenerate crossing point and non-degenerate branches, or four-fold degenerate crossing point with double degenerate conical branches), poppy-flower (four-fold degenerate crossing point with two pairs of non-degenerate mutually rotated conical branches), and fortune teller (with nodal lines). Further, we describe the nontrivial patterns of dispersions’ behavior in high symmetry points when symmetry is varied within a cluster. Namely, Clebsch–Gordan series of the products of spin representation with the integer ones are relevant when spin–orbit coupling is included, and clarify observed scenarios (gap closing, gap opening, cone preserving, cone splitting etc). Analogously, analysis of behavior of dispersions in transition from ordinary to gray group enlightens the role of time reversal symmetry. The results refine and expand data existing in literature, and interesting or even unexpected cases are singled out in discussion.
Topological theory of phase transitions
Authors: Gori Matteo , Franzosi Roberto , Pettini Giulio , Pettini Marco
Published: July 2022

The investigation of the Hamiltonian dynamical counterpart of phase transitions, combined with the Riemannian geometrization of Hamiltonian dynamics, has led to a preliminary formulation of a differential-topological theory of phase transitions. In fact, in correspondence of a phase transition there are peculiar geometrical changes of the mechanical manifolds that are found to stem from changes of their topology. These findings, together with two theorems, have suggested that a topological theory of phase transitions can be formulated to go beyond the limits of the existing theories. Among other advantages, the new theory applies to phase transitions in smallNsystems (that is, at nanoscopic and mesoscopic scales), and in the absence of symmetry-breaking. However, the preliminary version of the theory was incomplete and still falsifiable by counterexamples. The present work provides a relevant leap forward leading to an accomplished development of the topological theory of phase transitions paving the way to further developments and applications of the theory that can be no longer hampered.
Study of Saudi Arabian Manufacturing and Service Organization Sustainability and Future Research Directions
Authors: Al-Alqam Mohammed S , Rehman Ateekh Ur , Alsultan Marwan
Published: July 2022

Currently, organizations face a range of dynamic challenges to maintain long-term market sustainability. Examples of these challenges are developing and improving their product and or service quality, increasing operational efficiency, complying with safety regulations, enhancing the triple bottom line of agility in manufacturing products and satisfying customer demand. Saudi Arabia has a vision for 2030 where sustainability is one of the corner stones. Here the objective is to explore sustainability awareness in Saudi organizations and their commitment to sustainability; and to present a brief review of approaches adopted by researchers who have implemented sustainability evaluations in different organizations around the world. It is evident that Saudi manufacturing organizations continue to pursue long-term market sustainability, but researchers have not explored sustainability in detail. In particular, an assessment of the sustainability of Saudi manufacturing organizations is lagging. Further studies are needed to develop a model that can be used to assess the sustainability of Saudi manufacturing and service organizations.
Estimation of the Large Diameter Bored Pile Ultimate Capacity Using Different Design Methods: Assessment Study
Authors: Al-Atroush M E , Aloufi M.
Published: July 2022

In this paper, in situ measurements of two well-instrumented loading tests performed on large diameter bored piles (LDBP) have been utilized to assess the reliability of the predicted ultimate pile capacity using three settlement-based and capacity-based methods. The first test was conducted on a short LDBP with a 1.3m and 9.50 length. This LDBP was constructed in stiff clay soil and loaded till the achievement of the failure. While the second in-situ loading test was performed on a long LDBP with a 1.00 m diameter and 34.00 m length. This LDBP was constructed in multi-layered soil and examined under three axially loading and unloading cycles to obtain the ultimate load settlement relationship. Although this LDBP was loaded with an applied load of three times its working capacity, but no apparent failure was reached at the end of the loading test. Thus, two different methods are adopted to interpret the test data and determine the ultimate pile capacity. The obtained ultimate capacities of the two tests were utilized in an assessment study. The comparative analysis results showed a significant difference between the ultimate capacity obtained using three different methods and field measurements. Out of the three utilized methods in this study, the two settlement-based methods underestimated the LDBP ultimate capacity of the two LDBP cases; conversely, the third capacity-based method overestimated the ultimate capacity of the two LDBP cases.
Ancestral and vernacular architecture as contemporary heritage, tourist and cultural resource. The case of the “palafitos” and the route of the 16 UNESCO heritage churches of Chiloé, Chile
Authors: Pareti S , Rudolph L , Flores D , Valdebenito V
Published: July 2022

The present study aims to explore how spaces designed with ancestral and vernacular architecture can become a heritage, tourist and cultural resource.

The analysis of the stilt houses and the route of the 16 UNESCO heritage churches of Chiloé, Chile has been selected as a case study, since: (1) it is an ancestral and vernacular architecture unique in the world, (2) they are part of the cultural and patrimonial tourist offer of the Chilean Patagonia, (3) has a balance of patrimonial and intangible material conservation that has managed to keep the gentrification and identity of the territory under control, (4) its 16 churches have been declared patrimonial by UNESCO.

The methodology is developed through the analysis of a complete palafito from the constructive and architectural point of view, together with a church part of the patrimonial route. Followed by an analysis of press headlines and interviews, based on established parameters that allow understanding the link between architecture, transformation into a cultural and tourist resource together, and gentrification. It is concluded that the vernacular architecture of stilt houses and churches in Chiloé configures a valuable contemporary heritage resource that must be preserved and asserted in balance with the tourist dimension that it attracts thanks to its uniqueness.
Error driven Fuzzy Logic Controller (FLC) for Spherical Mobile Robot: Simulation & Experimental Performance Analysis
Authors: Kamis Nurul Nafisah , Ahmad Salmiah , Embong Abd. Halim , Sulaeman Erwin
Published: July 2022

Spherical mobile robot is a ball-shaped mobile robot that capable to move from one place to another to perform the desired tasks. The challenge for spherical mobile robot falls within control algorithm aspects, where it is nonlinear and highly under-actuated increases the difficulties to control its motion. In this paper, the potentiality of intelligent controller is explored to control the motion spherical mobile robot. An error driven Fuzzy Logic controller (FLC) which consist of modular of two Proportional-Derivative (PD) type FLC and a Proportional-Integral (PI) type FLC were designed and tested to control the position of the spherical mobile robot, angle of the rotation of the pendulum and the angular velocity of the spherical mobile robot, respectively. The performance of the controller was then optimized by tuning the input and output gain of the controller with Particle Swarm optimization (PSO) method. The performance of the robot without the controller and with optimized controller were compared and analysed. As a result, the performance of the system in the form of rise time and settling time of the robot to control its position managed to be reduced by 86% and 89% respectively with optimized PD-type. For PD-type FLC to control the rotation of the pendulum, it was capable to eliminate the overshoot and reduce it settling time by 35.5%. While the optimized PI-type FLC has managed to eliminate the steady state error and achieved it desired velocity setpoint in 1.2s. Lastly, all the designed controllers were successfully tested on the prototype of the spherical mobile robot to study the performance of the spherical mobile robot. However, the overall performance of the implemented designed controller has shown a minimum effectiveness. The controller managed to achieve the setpoint value but with low stability which result from the less accuracy of the hardware sensors.
The dry sliding wear behaviour of open cell aluminum foam against mild steel
Authors: Idriss A.N. Md , Kasolang S.
Published: July 2022

From one perspective, wear is a phenomenon of material loss due to surface friction and their failures are characterized by classifying changes in the surface morphology of the mating component. In the case of foam materials, such as open cell aluminum foams, having interconnected porosity associated with large surface area, they acquire minimal kinetic energy for mobility during friction. Foam materials are also well known for their good qualities in thermal and noise management. This sees the foam material as an effective alternative candidate to their parents solid alloy. The objective of this work is to investigate the wear behavior of the open cell aluminum foam fabricated using matrix infiltration method on the surface of rotating mild steel under the dry sliding condition. The surface profile due to wear, microhardness and weight losses of both the open cell aluminum foam and steel disk were measured. The surface profile used the downlighting and inclined at 45° lighting techniques for the favour of distinguished appearance under the optical microscopy observations. Generally all samples showed abrasive failures due to the cutting marks without adherence. High brightness under the downlight was not able to vary the cutting marks in sizes which made among those single striations width to appear almost similar. Comparing to the 45° inclined lights, a good contrast was obtained and so ranges of cutting width were seen to be equally distributed on that open cell aluminum pin. The technique using lighting at the 45° resulted clarity on worn surface area that is less efficient by the downlight. The low hardness at 47 HV with the open cell aluminum foam showed medium wear and greater weight loss than the 155 HV mild steel sample.
Structural Analysis of Continuous I Beam of Steel with Crack Using Finite Element Simulation
Authors: Rahnuma Mumtahina , Chowdhury Md. Mehadi Hassan , Ahmed Nihal , Ahmed Ashfaq
Published: July 2022

The statically indeterminate beam that is supported by three or more supports and at least one support that develops a reaction along the beam axis is known as a continuous beam. This type of beam is used in a large variety of structures as they show better resistance to seismic loads and lower deformity. However, due to the decay of steel or the increase of stresses, sometimes surface or sub-surface fissures develop in the material which is known as cracks. Because of the cracks in a structure, it may be vulnerable and start to age rapidly, which will eventually lead the structure to collapse. In this study, Abaqus CAE, a widely operated commercial software is used to simulate the cracks in a continuous I beam by the Finite Element Method. The surrounding crack zone is meshed with a smaller area due to its sensitiveness. Initially, suitable steel is selected among the major types of steel by evaluating their stress-strain curve. Then a continuous I beam of that steel with crack is simulated and the effect of the crack on the stresses is analyzed. The crack is safer when it forms on the part of the structure that is over-support. The risk of failure of a structure increases with the increasing distance of the crack from support. The greater crack depth poses a greater risk to the structure on the other hand increasing crack width has less effect on the stability of the structure
Investigation on mechanical and tribological properties of magnesite reinforced aluminium 6061 composites
Authors: Ayyappan S , Saminathan M , Selvarasan R
Published: July 2022

During the sintering process in the shaft kiln of refractory factories, a considerable quantity of materials is separated and dumped as Waste Magnesite (WM). The other superior grades, Lightly-Calcined Magnesite (LCM) and Dead-Burned Magnesite (DBM), are separated at different temperatures from the shaft kiln. The WM materials still have 8% of magnesium with some sand and dust particles in huge ranges. These materials are primarily used in the applications of medicine and fertilizers and animal feed processing and additives. This work investigates the potential of WM particles as reinforcement materials in the Al 6061 alloy matrix. In order to compare the characteristics of WM-based composite, LCM and DBM powders were also considered as reinforcement particles. The WM, LCM, and DBM particles were mixed with a 15% weight ratio to Al 6061 alloy, and composites were fabricated using the Stir Casting method. The surface morphology investigations through Scanning Electron Microscopy (SEM) revealed that these particles were well distributed and dispersed within the alloy matrix and with good interfacial adhesion. It is noted that Al 6061/15% wt. LCM composite possesses a better tensile strength than Al 6061/15% wt. WM and Al 6061/15% wt.DBM composites. The impact value produced by the WM-based composite is better than the LCM and DBM composites. The Wear Rate and Coefficient of Friction (COF) were examined through a Pin-on-Disc apparatus. Al 6061/15% wt. WM composite tested a low wear rate (9.74 × 10−6 mm3 m)−1. The results show that Al 6061/15% wt. LCM composite achieved the least COF value of 0.681 at an applied load of 0.5 Kg and a sliding distance of 2826 m. The results prove that the wastage magnesite is good enough and the most robust reinforcement material for Aluminum 6061 alloy-based composite.
Radiofrequency impedance spectroscopy of biological tissues under heating by homogeneous laser radiation
Authors: Sovin Kirill , Kovalenko Nikita , Anpilov Vladimir , Ryabushkin Oleg
Published: July 2022

We have developed an original method to measure the temperature dependence of the biological tissue electrical properties based on its heating by homogeneous optical radiation.The conventional approach in hyperthermia research involves heating due to a thermal conductivity through the surface of the sample. The novel technique is based on the emission of heat sources in the sample volume caused by the absorption of optical radiation.The method was verified using chicken liver and aloe parenchyma samples, which were uniformly irradiated in a special chamber with an optically scattering inner coating. The electrical impedance of the samples was measured using a 4-electrode technique in the frequency range 100 Hz−1 MHz. In order to approximate and analyze the electrical impedance module, an equivalent electrical circuit based on the Cole-Cole function was used and the dependences of the approximation parameters on time and temperature were obtained. Applying the Arrhenius formulation to the kinetics of low-frequency resistance, we obtained the parameters of the kinetics of degradation of the biological tissues (critical temperature

T

cr

and activation energy

E

a

):

E

a

=
(
16
±
4
)
·

10

5

J

·

mol−1,

T

cr

=
63
±
1

°C for the aloe parenchyma and

E

a

=
(
4.5
±
2
)
·

10

5

J

·

mol−1,

T

cr

=
83
±
1

°
C

for the chicken liver.
Risk assessment of human exposure to lead and cadmium in tissues of Blackchin Tilapia (Sarotherodon melanotheron) from an intertidal creek in the Niger Delta region of Nigeria
Authors: Ihunwo Owhonda Chikeru , Ibezim-Ezeani Millicent Uzoamaka , Wekpe Vremudia Onyeajoma , Shahabinia Amir Reza , Bonnail Estefanía , Mmom Prince Chinedu , Horsfall (Jnr) Michael
Published: July 2022

The present study investigated the risk associated with concentrations of lead and cadmium in tissues (gills, livers and muscles) of Blackchin tilapia (Sarotherodon melanotheron) from upstream and downstream regions of an intertidal creek in Rivers State, Nigeria. The trend of Cd in fish tissues and water was as follows: muscle > liver > gills > water. The concentration of Cd in fish gills was higher in downstream fish when compared to upstream fish. The mean Cdmg kg
−1 in fish gills was 0.048 ± 0.015—upstream and 0.549 ± 0.152—downstream, 0.037 ± 0.030—upstream and 0.769 ± 0.100—downstream, 0.026 ± 0.015—upstream and 0.902 ± 0.118—downstream, and 0.040 ± 0.018—upstream and 0.727 ± 0.157—downstream in December, January, February and March respectively. The trend of Pb in fish tissues and water was as follows: muscle > liver > gills > water. Pb was generally higher in fish sampled downstream when compared to those sampled upstream of the creek. Fish gills in upstream fishes had Pb of 6.324 ± 0.388 mg kg−1, 5.140 ± 1.249 mg kg−1, 5.459 ± 0.471 mg kg−1 and 5.730 ± 0.859 mg kg−1 while downstream fishes had Pb 7.732 ± 0.640 mg kg−1, 9.401 ± 0.711 mg kg−1, 7.575 ± 0.624 mg kg−1 and 7.644 ± 0.637 mg kg−1 in December, January, February and March respectively. Cdfish gills < Food and Agriculture Organization (FAO) maximum permissible limit (MPL), Cdfish muscles and Cdlivers < MPL for FAO, FAO/WHO and WHO. Pbgills upstream and downstream > MPL for FAO, FAO/WHO and WHO. Pb and Cd did not indicate non-carcinogenic risks to human health owing to the consumption of fish up- and downstream. In the present study, fishes sampled upstream showed low cancer risk in adults, however, cancer risk index (CRI) indicated moderate cancer risk in children (male and female). For fishes sampled downstream, CRI indicated low risk for adults and male children, but a moderate risk for female children.
Neuromorphic computing for attitude estimation onboard quadrotors
Authors: Stroobants Stein , Dupeyroux Julien , de Croon Guido C H E
Published: July 2022

Compelling evidence has been given for the high energy efficiency and update rates of neuromorphic processors, with performance beyond what standard Von Neumann architectures can achieve. Such promising features could be advantageous in critical embedded systems, especially in robotics. To date, the constraints inherent in robots (e.g., size and weight, battery autonomy, available sensors, computing resources, processing time, etc), and particularly in aerial vehicles, severely hamper the performance of fully-autonomous on-board control, including sensor processing and state estimation. In this work, we propose a spiking neural network capable of estimating the pitch and roll angles of a quadrotor in highly dynamic movements from six-degree of freedom inertial measurement unit data. With only 150 neurons and a limited training dataset obtained using a quadrotor in a real world setup, the network shows competitive results as compared to state-of-the-art, non-neuromorphic attitude estimators. The proposed architecture was successfully tested on the Loihi neuromorphic processor on-board a quadrotor to estimate the attitude when flying. Our results show the robustness of neuromorphic attitude estimation and pave the way toward energy-efficient, fully autonomous control of quadrotors with dedicated neuromorphic computing systems.
What Structural Racism Is (or Is Not) and How to Measure It: Clarity for Public Health and Medical Researchers
Authors: Dean Lorraine T , Thorpe Roland J
Published: July 2022

Interest in studying structural racism’s impacts on health has grown exponentially in recent years. Across these studies, there is much heterogeneity in the definition and measurement of structural racism, leading to mixed interpretations of structural racism’s impact on health. A precise definition of structural racism can offer conceptual clarity to inform what mechanisms to investigate and is imperative for conducting high-quality research on it and dismantling it. In this commentary, we trace the evolution of the definitions of structural racism and suggest ways in which the measurement of structural racism should move forward given these definitions.
Prevalence of Obstructive Sleep Apnea Is Increased in Patients With Inflammatory Bowel Disease: A Large, Multi-Network Study
Authors: Hoffman Kyle , Mansoor Emad , Panhwar Muhammad Siyab , Regueiro Miguel , Cooper Gregory , Qazi Taha
Published: July 2022

Background

Crohn’s disease (CD) and ulcerative colitis (UC) involve an inflammatory state where sleep dysregulation is common. Little is known about implications, if any, of inflammatory bowel disease (IBD) on the development of obstructive sleep apnea (OSA). This study aims to investigate if IBD patients are at higher risk for OSA.

Methods

This retrospective multivariate analysis utilized a commercial database named Explorys (IBM Watson). We identified patients from 1/2015 to 1/2020 with UC and CD. Cohorts of these patients with and without OSA were then created and prevalence values were obtained. A multivariate analysis was used to correct for several potential confounding variables.

Results

The overall prevalence of OSA was 7.8% in UC and 7.2% in CD, as compared with a prevalence of 4.3% in non-IBD patients (odds ratio [OR] for UC: 1.9 [95% CI 1.86–1.94, P < .0001], OR for CD: 1.72 [95% CI 1.69–1.76, P < .0001]). In multivariate analysis, age above 65, Caucasian race, male sex, obesity, smoking, hypertension, and diabetes were all independent risk factors for the development of OSA, with obesity being the most significant. After controlling for the listed variables in the multivariate analysis, IBD was an independent risk factor associated with OSA (OR 1.46, 95% CI 1.43–1.48).

Conclusions

In this large population-based study, IBD was independently associated with increased prevalence of OSA. This has implications for screening for OSA in IBD, as well as management of other risk factors for OSA in IBD.