bluuebunny/crossref_metadata_2025 huggingface dataset:
Flow and aerosol dispersion from wind musical instruments
Authors: Brosseau Quentin , Ran Ranjiangshang , Graham Ian , Jerolmack Douglas J. , Arratia Paulo E.
Published: July 2022

In the midst of the COVID-19 pandemic, many live musical activities had to be postponed and even canceled to protect musicians and the audience. Orchestral ensembles face a particular challenge of contamination, because they are personally heavy and instrumentally diverse. A chief concern is whether wind instruments are vectors of contamination through aerosol dispersion. This study, made possible by the participation of members of The Philadelphia Orchestra, brings insight into the modes of production and early life of aerosols of human origin emitted by wind instruments. We find that these instruments produce aerosol levels that are comparable to normal speech in quantity and size distribution. However, the exit jet flow speeds are much lower than violent expiratory events (coughing and sneezing). For most wind instruments, the flow decays to background indoor-air levels at approximately 2 m away from the instrument's opening. Long range aerosol dispersion is, thus, via ambient air currents.
A new boundary layer integral method based on the universal velocity profile
Authors: Cantwell Brian J. , Bilgin Eylul , Needels Jacob T.
Published: July 2022

A recently developed mixing length model of the turbulent shearing stress in wall bounded flows has been used to formulate a universal velocity profile (UVP) that provides an effective replacement for the widely used Coles wall-wake formulation. Comparisons with both direct numerical simulation and experimental data demonstrate the ability of the profile to approximate a wide variety of wall-bounded flows. The UVP is uniformly valid from the wall to the boundary layer edge and for all Reynolds numbers from zero to infinity. There is no presumption of logarithmic dependence of the velocity profile outside the viscous wall layer so the profile can accurately approximate low Reynolds number turbulent boundary layers. The effect of a pressure gradient is included in the UVP through the introduction of a modified Clauser parameter that correlates well with the parameters that determine the wake portion of the velocity profile. The inherent dependence of the UVP on Reynolds number, extended to include the effect of pressure gradient, enables it to be used as the basis of a new method for integrating the von Kármán boundary layer integral equation for a wide variety of attached wall bounded flows. To illustrate its application, the UVP is used to determine the zero-lift drag coefficient of the Joukowsky 0012 and NACA (National Advisory Committee for Aeronautics) 0012 airfoils over a wide range of chord Reynolds numbers.
Vulnerability of 14 elasmobranchs to various fisheries in the southern Gulf of Mexico
Authors: Bravo-Zavala Fátima Guadalupe , Pérez-Jiménez Juan Carlos , Tovar-Ávila Javier , Arce-Ibarra Ana Minerva
Published: July 2022

Context Shark and ray fisheries in the southern Gulf of Mexico (GOM) are multispecific and use diverse fishing gear in multiple coastal areas. Aim Because no catch and fishing effort records by species exist, the aim of this study was to estimate the species’ vulnerability to fisheries through limited-data assessment methods. Methods The vulnerability to 14 fisheries through the productivity and susceptibility analysis (PSA) and rebound-potential method were estimated for 14 elasmobranchs. Key results Carcharhinus falciformis, Carcharhinus plumbeus and Sphyrna lewini among sharks, besides Hypanus americanus and Aetobatus narinari among rays, had the highest vulnerability and the lowest rebound potential. The sensitivity tests showed that the most significant differences in cumulative vulnerability (Cv) occur between two alternative widely applied PSA approaches. Cv determined from scores averaged over a range of susceptibility attributes tends to be higher than the product of the scores of four standard susceptibility attributes. Conclusions Significant correlations between Cv of Approach 1 and rebound-potential scenarios were estimated, indicating a general pattern in which the species’ rebound-potential increases while the vulnerability decreases. Implications The correlation between Cv (Approach 1) and rebound-potential highlights the suitability of PSA when enough information is available on the interactions of fisheries and populations.
ATG7 is a haploinsufficient repressor of tumor progression and promoter of metastasis
Authors: Long Jaclyn S. , Kania Elżbieta , McEwan David G. , Barthet Valentin J. A. , Brucoli Martina , Ladds Marcus J.G.W. , Nössing Christoph , Ryan Kevin M.
Published: July 2022

The role of autophagy in cancer is complex. Both tumor-promoting and tumor-suppressive effects are reported, with tumor type, stage and specific genetic lesions dictating the role. This calls for analysis in models that best recapitulate each tumor type, from initiation to metastatic disease, to specifically understand the contribution of autophagy in each context. Here, we report the effects of deleting the essential autophagy gene
Atg7
in a model of pancreatic ductal adenocarcinoma (PDAC), in which mutant

Kras
G12D

and mutant

Trp53
172H

are induced in adult tissue leading to metastatic PDAC. This revealed that
Atg7
loss in the presence of

Kras
G12D

/+
and

Trp53
172H

/+
was tumor promoting, similar to previous observations in tumors driven by embryonic

Kras
G12D

/+
and deletion of
Trp53
. However,
Atg7
hemizygosity also enhanced tumor initiation and progression, even though this did not ablate autophagy. Moreover, despite this enhanced progression, fewer
Atg7
hemizygous mice had metastases compared with animals wild type for this allele, indicating that ATG7 is a promoter of metastasis. We show, in addition, that
Atg7
+/−
tumors have comparatively lower levels of succinate, and that cells derived from
Atg7
+/−
tumors are also less invasive than those from
Atg7
+/+
tumors. This effect on invasion can be rescued by ectopic expression of
Atg7
in
Atg7
+/−
cells, without affecting the autophagic capacity of the cells, or by treatment with a cell-permeable analog of succinate. These findings therefore show that ATG7 has roles in invasion and metastasis that are not related to the role of the protein in the regulation of autophagy.
Memory from coupled instabilities in unfolded crumpled sheets
Authors: Shohat Dor , Hexner Daniel , Lahini Yoav
Published: July 2022

Crumpling an ordinary thin sheet transforms it into a structure with unusual mechanical behaviors, such as enhanced rigidity, emission of crackling noise, slow relaxations, and memory retention. A central challenge in explaining these behaviors lies in understanding the contribution of the complex geometry of the sheet. Here we combine cyclic driving protocols and three-dimensional (3D) imaging to correlate the global mechanical response and the underlying geometric transformations in unfolded crumpled sheets. We find that their response to cyclic strain is intermittent, hysteretic, and encodes a memory of the largest applied compression. Using 3D imaging we show that these behaviors emerge due to an interplay between localized and interacting geometric instabilities in the sheet. A simple model confirms that these minimal ingredients are sufficient to explain the observed behaviors. Finally, we show that after training, multiple memories can be encoded, a phenomenon known as return point memory. Our study lays the foundation for understanding the complex mechanics of crumpled sheets and presents an experimental and theoretical framework for the study of memory formation in systems of interacting instabilities.
Voltage-gated sodium channelscn8ais required for innervation and regeneration of amputated adult zebrafish fins
Authors: Osorio-Méndez Daniel , Miller Andrew , Begeman Ian J. , Kurth Andrew , Hagle Ryan , Rolph Daniela , Dickson Amy L. , Chen Chen-Hui , Halloran Mary , Poss Kenneth D. , Kang Junsu
Published: July 2022

Teleost fishes and urodele amphibians can regenerate amputated appendages, whereas this ability is restricted to digit tips in adult mammals. One key component of appendage regeneration is reinnervation of the wound area. However, how innervation is regulated in injured appendages of adult vertebrates has seen limited research attention. From a forward genetics screen for temperature-sensitive defects in zebrafish fin regeneration, we identified a mutation that disrupted regeneration while also inducing paralysis at the restrictive temperature. Genetic mapping and complementation tests identify a mutation in the major neuronal voltage-gated sodium channel (VGSC) genescn8ab. Conditional disruption ofscn8abimpairs early regenerative events, including blastema formation, but does not affect morphogenesis of established regenerates. Whereasscn8abmutations reduced neural activity as expected, they also disrupted axon regrowth and patterning in fin regenerates, resulting in hypoinnervation. Our findings indicate that the activity of VGSCs plays a proregenerative role by promoting innervation of appendage stumps.
Verbal and situational irony
Authors: Belaj Branimir , Tanacković Goran
Published: July 2022

Unlike metaphor and metonymy, irony has no “standardized” conceptual tools to rely on for its detection. The detection of irony proceeds entirely on-line; its comprehension does not rest on prior acquisition of conventional figures in the processes of language learning; it rests on our ability to establish, creatively and on-line, a dynamic relationship between our knowledge of language and the relevant information about the communicative situation and its protagonists. The goal of the present study is to shed light on the conceptual underpinnings of on-line interpretation of two main types of irony, verbal and situational, within a communicative context, using the methodological tools of cognitive linguistics, specifically Blending Theory (Fauconnier & Turner, 2002) and frame semantics (Fillmore, 1977, 1982, 1985).
Effects of doping concentration and annealing temperatures on the ferroelectric memory properties of yttrium doped HfO2
Authors: Chen Haiyan , Luo Hang , Yuan Xi , Yang Junliang , Zhang Dou
Published: July 2022

HfO2 has been widely studied in nonvolatile memories owing to its advantages including wide bandgap, superior ferroelectricity, low power and high density. Herein, yttrium doped hafnium (Y: HfO2) films were fabricated on Si (100) substrate by chemical solution deposition method. Effect of Y contents on the structural and electrical performance of Y: HfO2 ferroelectric films was carefully investigated in the range of 0–10 mol%. Results revealed that Y: HfO2 was crystallized from m-phase to c/o-phase with the increase of Y contents which exhibited a strong dependence on the concentrations of oxygen vacancies. 7 mol% Y: HfO2 achieved the highest remnant polarization of 23.37 μC cm−2 after being annealed at 700 °C for 60 s in O2 atmosphere. Significant domain switching patterns could be written by piezoelectric force microscope indicating the good ferroelectricity in 7 mol% Y: HfO2. Lower and higher annealing temperatures were not beneficial for the improvement of ferroelectricity due to the large leakage current and over-crystallization, respectively. This work would provide useful guidance for HfO2-based films in future memories with great potential.
Single-beam ion source enhanced growth of transparent conductive thin films
Authors: Tran Thanh , Kim Young , Baule Nina , Shrestha Maheshwar , Zheng Bocong , Wang Keliang , Schuelke Thomas , Fan Qi Hua
Published: July 2022

A single-beam ion source was developed and used in combination with magnetron sputtering to modulate the film microstructure. The ion source emits a single beam of ions that interact with the deposited film and simultaneously enhances the magnetron discharge. The magnetron voltage can be adjusted over a wide range, from approximately 240 to 130 V, as the voltage of the ion source varies from 0 to 150 V, while the magnetron current increases accordingly. The low-voltage high-current magnetron discharge enables a ‘soft sputtering mode’, which is beneficial for thin-film growth. Indium tin oxide (ITO) thin films were deposited at room temperature using a combined single-beam ion source and magnetron sputtering. The ion beam resulted in the formation of polycrystalline ITO thin films with significantly reduced resistivity and surface roughness. Single-beam ion-source-enhanced magnetron sputtering has many potential applications in which low-temperature growth of thin films is required, such as coatings for organic solar cells.
Microplasma emission performances dependent on silicon nanowires morphologies
Authors: Ma Xiaoqin , Chen Lichi , Wang Yaogong , Wang Wenjiang , Zhang Xiaoning
Published: July 2022

Silicon nanowires (SiNWs) are introduced into microdischarge to improve microplasma properties due to its field emission electrons and field enhancement effect. The geometrical arrangement and dimensional features of SiNWs have desicive influence on field emission properties, thus the dependence of microplasma emission performances on the SiNWs morphologies is investigated in this paper. The different morphologies of SiNWs can be prepared by electrocatalytic metal-assisted chemical etching with varied etching currents. With the increase of etching current from 3 mA to 30 mA (AgNO3:HF:H2O2 = 0.02:4.6:0.1 mol l−1, deposition time 1 min and etching time 10 min), the field emission current density
J
of the SiNWs prepared at 20 mA etching current is the largest ∼0.28 mA cm−2 at a field 4.5 V μm−1, and turn-on field is the lowest of 3.52 V μm−1. Accordingly, the microplasma in the device fabricated on the SiNWs-decorated substrate (etching current at 20 mA) has the strongest average emission intensity of ∼11 565 a.u., the minimal relative standard deviation of emission intensity 4.9% and the fastest propagation velocity of 471 km s−1. The field emission electrons of SiNWs could inject more seed electrons into microcavity which causes higher electron collision probability, and the field enhancement effect at tips of SiNWs can provide more energy for the charged particles, which are helpful to the microdischarge. The most difficulty is to balance the distance of emitters and the percentage of SiNWs in entire emission region because the shielding effect will reduce while the surface emitter numbers will decrease when the distance of emitters increases. Here, a ‘proper percentage of SiNWs’ of 19.3% is obtained what indicates that if SiNWs percentage is greater than the threshold, field enhancement factor β
eff is weakened by the decrease of aspect ratio and the increase of percentage. When SiNWs percentage is less than 19.3%, β
eff will increase and be dominated by the percentage of SiNWs. The results are significant for the application of SiNWs in microdischarge devices.
Charge-transfer effect in Fe 2p core-level x-ray photoemission spectra of trivalent Fe oxides: LDA + DMFT study
Authors: Higashi Keisuke , Yamaguchi Tatsuya , Takahashi Yoshihiro , Hariki Atsushi
Published: July 2022

Motivated by recent hard x-ray photoemission spectroscopy (XPS) experiment for trivalent Fe oxides Sr2FeMoO6 (ferrimagnetic correlated metal) and LaFeO3 (antiferromagnetic Mott insulator) (Phuyal et al 2021 J. Phys. Chem. C 125 11249–56), we present a theoretical analysis of the Fe 2p core-level spectra using a computational method based on local density approximation combined with dynamical mean-field theory. We find that a nonlocal screening (NLS) effect in the XPS final states is crucial for interpreting the experimental XPS result of both the Fe oxides. A close relationship between the NLS feature in core-level spectra and a long-range magnetic ordering is emphasized.
Majorana corner states in an attractive quantum spin Hall insulator with opposite in-plane Zeeman energy at two sublattice sites
Authors: Wu Ya-Jie , Tu Wei , Li Ning
Published: July 2022

Higher-order topological superconductors and superfluids (SFs) host lower-dimensional Majorana corner and hinge states since novel topology exhibitions on boundaries. While such topological nontrivial phases have been explored extensively, more possible schemes are necessary for engineering Majorana states. In this paper we propose Majorana corner states could be realized in a two-dimensional attractive quantum spin-Hall insulator with opposite in-plane Zeeman energy at two sublattice sites. The appropriate Zeeman field leads to the opposite Dirac mass for adjacent edges of a square sample, and naturally induce Majorana corner states. This topological phase can be characterized by Majorana edge polarizations, and it is robust against perturbations on random potentials and random phase fluctuations as long as the edge gap remains open. Our work provides a new possibility to realize a second-order topological SF in two dimensions and engineer Majorana corner states.
A synergistic effect of the ion beam sputtered NiO
x
hole transport layer and MXene doping on inverted perovskite solar cells
Authors: Din Muhammad Faraz Ud , Held Vladimir , Ullah Sami , Sousani Shima , Omastova Maria , Nadazdy Vojtech , Shaji Ashin , Siffalovic Peter , Jergel Matej , Majkova Eva
Published: July 2022

The synergistic effect of high-quality NiO
x
hole transport layers (HTLs) deposited by ion beam sputtering on ITO substrates and the Ti3C2T
x
MXene doping of CH3NH3PbI3 (MAPI) perovskite layers is investigated in order to improve the power conversion efficiency (PCE) of p-i-n perovskite solar cells (PSCs). The 18 nm thick NiO
x
layers are pinhole-free and exhibit large-scale homogeneous surface morphology as revealed by the atomic force microscopy (AFM). The grazing-incidence x-ray diffraction showed a 0.75% expansion of the face-centered cubic lattice, suggesting an excess of oxygen as is typical for non-stoichiometric NiO
x
. The HTLs were used to fabricate the PSCs with MXene-doped MAPI layers. A PSC with undoped MAPI layer served as a control. The size of MAPI polycrystalline grains increased from 430 ± 80 nm to 620 ± 190 nm on the doping, as revealed by AFM. The 0.15 wt% MXene doping showed a 14.3% enhancement in PCE as compared to the PSC with undoped MAPI. The energy-resolved electrochemical impedance spectroscopy revealed one order of magnitude higher density of defect states in the band gap of MXene-doped MAPI layer, which eliminated beneficial effect of reduced total area of larger MAPI grain boundaries, decreasing short-circuit current. The PCE improvement is attributed to a decrease of the work function from −5.26 eV to −5.32 eV on the MXene doping, which increased open-circuit voltage and fill factor.
Electron energy probability function measurement in a 2 MHz and 13.56 MHz dual-frequency capacitively coupled argon plasma
Authors: Hong Young-Hun , Kim Tae-Woo , Kim Beom-Seok , Lee Moo-Young , Chung Chin-Wook
Published: July 2022

The effect of low-frequency power and high-frequency power on the electron energy probability function (EEPF) and the physical and electrical characteristics of plasma are experimentally investigated in a dual-frequency capacitively coupled plasma. RF powers of 2 MHz (low-frequency) and 13.56 MHz (high-frequency) are simultaneously applied to an electrode. EEPFs and DC self-bias voltages (V
DC) are measured as one of the two RF powers is increased while the other is fixed. When the 2 MHz power increases at a fixed 13.56 MHz power, the electron density decreases, and the electron temperature increases with the decrease in the population of low-energy (below 5 V) electrons in the EEPF. Note that the increase in the low-frequency power is accompanied by a large decrease in V
DC, which is related to the ion energy. On the other hand, when 13.56 MHz power increases at a fixed 2 MHz power, the electron density and the electron temperature significantly increase with the increase in the population of high-energy (above 5 V) electrons in the EEPF, while V
DC decreases slightly. Experimental results show that the increase in the low-frequency power enhances the ion energy, and the increase in the high-frequency power enhances electron heating and ionization efficiency.
Source material valuation of charge plasma based DG-TFET for RFIC applications
Authors: Goyal Preeti , Srivastava Garima , Madan Jaya , Pandey Rahul , Gupta R S
Published: July 2022

This paper seeks to present a comprehensive analysis to check the viability of four different source materials in a charge plasma-based double gate tunnel field effect transistor (CP-DGTFET) as RF/microwave systems components. This work aims to provide a comparative study of the electrical and analog parameters of three devices (labeled as D-II, D-III, D-IV) with Si0.5Ge0.5, Ge, Mg2Si as the source material with a conventional Si source homojunction CP-DGTFET (referred as D-I). In addition, linearity and distortion are investigated. The selection of the source material illustrates the effect on the band structure at heterojunctions, as a combined effect of low bandgap and electron affinities of the material used. Results obtained through numerical simulations show that the device D-IV with Mg2Si source shows excellent performance parameters with maximum I
ON (4.6 × 10−3 A µm−1) and minimum V
th (0.26 V). Also, the switching ratio (1013) and SS (10.89 mV/decade) offered by D-IV is the best among all four devices investigated. Various linearity FOM’s viz. transconductance and its higher order derivatives (g
m
, g
m2
, g
m3), higher order voltage intercept points (V
IP2
, V
IP3), third-order intercept input power, third-order intermodulation distortion, 1 dB compression point, 2nd and 3rd order harmonic distortion, and total harmonic distortions (THD) have also been examined. All of this research was carried out using the Atlas Silvaco simulation tool. This study reveals that the Mg2Si source CP-DGTFET is best suited for high-frequency, low-power and high linearity applications in modern communication systems.
Finite element model updating of microwave welded lap joint with direct updating algorithm
Authors: Bagha Ashok Kumar , Tiwari Shivashrit , Kumari Shivani , Samyal Rahul , Bedi Raman , Sharma Nitin , Bahl Shashi
Published: July 2022

Microwave joining is a non-conventional joining method that can be used to join bulk metals. Different types of joints such as butt-joint, lap joint, etc can be successfully joined with this novel green technique of joining. In this paper, a domestic microwave oven having a power output of 700W, frequency of 2.45 GHz, and capacity of 25L is used to weld the SS202-SS202 and SS304-SS304 bulk metals. To characterize the lap joints Vicker’s hardness test and SEM of the welded specimens are carried out. The experimental modal analysis is used to measure the experimental eigenvalues and eigenvectors of the welded lap joints. The finite element method has been used to develop the simulated finite element model of the microwave welded joints. The developed finite element model may be very beneficial to predict the dynamic characteristics of the welded structures. However, the finite element method is a numerical tool that gives approximate results. The finite element modeling of the structures depends upon various uncertain factors such as structural material properties, dimensions, boundary conditions, etc Due to these uncertainties in the simulated finite element model, there is always an error between the simulated and experimental observations. In this paper, a lap joint of bulk metals is fabricated by using microwave hybrid heating and a finite element model updating technique such as a direct updating algorithm is proposed to update its simulated finite element model. The objective is to update the simulated mass and the stiffness matrices of the microwave welded lap joint. The experimental modal analysis is used to measure the natural frequencies of the lap joint specimen experimentally. It is observed that the direct updating algorithm can successfully update the simulated finite element model of the welded joints and reduces the error between the simulated and experimental natural frequencies. It is found that the maximum error between the predicted and measured natural frequencies reduces to 0.56% by using the proposed algorithm for welded joints.
Band gap properties and self-collimation in a tenfold quasicrystal structure photonic crystals applying multicircular ring scatterers
Authors: Zhou Yang , Zhang Zhi-Ran , Ji Hui , Zhang Hai-Feng
Published: July 2022

In this paper, a kind of tenfold photonic quasicrystals based on the Penrose puzzle theory with the application of multicircular ring scatterers (MCRSs) is presented. It is divided into four kinds of square supercells and employed in a square lattice to constitute the first-order (1st), second-order (2nd), third-order (3rd), and fourth-order (4th) tenfold quasicrystal structure photonic crystals (TFQCSPCs) accordingly. In an attempt to evaluate the dispersion maps and equifrequency contour (EFC) profiles of such long-range ordered but not really periodic TFQCSPCs, an enhanced plane wave expansion (PWE) method is adopted. The photonic crystals (PCs) discussed in this paper are first classified into two major categories, air hole and dielectric column types which will be referred to as type 1, type 2 respectively in the following. The varying features of photonic band gaps (PBGs) of TFQCSPCs are inquired about by changing the refractive index (n) of the relevant medium and the number of rings (H) of MCRSs under two broad prerequisites of type 1 and type 2 PCs. The results are also compared with the associated properties of PBGs of traditional square lattice PCs (TSLPCs) and traditional triangular lattice PCs (TTLPCs) which employ MCRSs. Then, the 1st and 2nd TFQCSPCs and TSLPCs are fabricated in the form of hollow air holes dug in the silicon plate, and the transformation of their PBGs and EFCs is researched when the width (W) and H of the ring are adjusted. The possibility of implementing the phenomenon of polarization-insensitive self-collimation (PISC) in TFQCSPCs and TSLPCs is explored by examining the smoothest EFCs in EFC mappings. Eventually, our work actualizes the PISC phenomenon at seven normalized frequency (NF) values of 0.074, 0.168, 0.170, 0.172, 0.265, 0.270, and 0.297, which fills the gap of the PISC phenomenon in the low-frequency domain.
Non-Gaussian signatures of a thermal Big Bang
Authors: Mylova Maria , Moschou Marianthi , Afshordi Niayesh , Magueijo João
Published: July 2022

What if Big Bang was hot from its very inception? This is possible in a bimetric theory
where the source of fluctuations is thermal, requiring the model to live on a critical boundary in
the space of parameters and can be realized when an anti-DBI brane moves within an EAdS
2 ×
E
3 geometry. This setup renders the model unique, with sharp predictions for the scalar
spectral index and its running. We investigate the non-Gaussian signatures of this thermal
bimetric model, or “bi-thermal” for short. We adapt the standard calculation of
non-Gaussianities for P(X,ϕ) models to the thermal nature of the model, emphasising how the
bi-thermal peculiarities affect the calculation and alter results. This leads to precise
predictions for the shape and amplitude of the three-point function of the bi-thermal model (at
tree-level): f
local
NL = -3/2 and f
equil
NL = -2 + 4 √(3)π/9
≃ 0.4. We also discover a new shape of flattened non-gaussianity ∝
(k
1 + k
2 - k
3)-3/2 + permutations, which is expected due to the excited thermal initial
conditions. These results, along with our earlier predictions for the scalar power spectrum,
provide sharp targets for the future generation of cosmological surveys.
Influence of the scale factor on the mechanical properties of heterogeneous welded joints
Authors: Terentyev E V , Gudenko A V , Zhgut D A , Borodavkina K T , Marchenkov Yu A , Kozyrev Kh M , Yakhontov A I , Santalova Yu V
Published: July 2022

The influence of the scale factor on the strength properties of welded products with pronounced mechanical inhomogeneity presented in the formation of a soft zone was investigated. Dissimilar welded joints were performed by electron beam welding and consisted of 12Kh18N10T austenitic steel and low-carbon ferritic steel. Interrelation of the ultimate tensile strength of the welded joints and the relative width of the soft zone was obtained for samples of three different scale levels. The growth in strength properties with a proportional decrease in the dimensions of the welded products was indicated.
Research of the technological methods influence on the formation of structure and properties during the additive growth of products from nickel chromium steels of the austenitic class by plasma-jet hard facing methods
Authors: Olshanskaya T V , Dushina A Y , Trushnikov D N
Published: July 2022

The paper considers the influence of a change in the heat rate of a source with time by means of slope control, using the example of plasma-jet hard facing, as well as changes in the original structure due to laminated cool post weld upsetting of the pads, using the example of plasma-jet heat-facing with a consumable electrode (Plasma-MIG). It was found that the formation of the structure is accompanied by metal deposits transcrystallization. It is shown that the use of vibratory actions on the liquid bath by slope control modulating during plasma surfacing contributes to the partial suppression of transcrystallization of the metal deposit: the direction of columnar crystallites growth changes relative to the previous layer, contributes to the refinement of the pine-tree structure, which leads to a change in mechanical characteristics. The best properties are observed when surfacing with slope control with a frequency of 15000 Hz. The use of laminated cool post weld upsetting during the plasma-jet hard-facing by consumable electrode reduces the transcrystallization of the metal deposit. It forms dendritic crystals of an equiaxial form, which leads to the reduction of the morphological grain flow, and the strength characteristics of the fused on alloy exceeds the level of the metal durability fused on without post weld upsetting and materials obtained by traditional technologies. However, the moldability characteristics remain at a high level.
Enhancing Adsorption Ice Maker Productivity using Beds of Aluminium Foam Packed with Activated Carbon
Authors: Elsheniti M B , Al-Ansary H , Orfi J , El-Leathy A , Eissa M S , Elsamni O
Published: July 2022

The adsorption refrigeration system driven by solar energy is a promising sustainable solution to tackle the growing demand for cooling and meet environmental regulations as well. In addition, the increase in refrigeration needs is in phase with the increase in the abundant solar energy in the Middle East. This study aims at numerically investigating the utilize of a high adsorption performance material namely Maxsorb III, a type of activated carbon, packed in an advanced aluminium foam bed to produce ice from two-bed adsorption system. A detailed 2-D axisymmetric transient model considering mass, momentum, and energy balance equations coupled with isotherms and kinetic models in the adsorbent domain to describe the adsorption phenomena was developed and used for the simulations. Results of a typical packed bed using finned tube configuration were used as a base model to compare the performance enhancement. The aluminium foam-based system performance outperformed the base model in producing the ice by 16.8% at a high cycle time of 1200 s, regeneration temperature of 90°C, and foam thickness of 5 mm. Furthermore, the coefficient of performance and specific cooling power increased by 26.7% and 27.9%, respectively, driven by the considerable enhancement in the bed mass and heat transfer due to the use of metal foam.
A novel low-cost plant-based adsorbent from Red Oak (Quercus rubra) Acorns for wastewater treatment: Kinetic study on removal of dye from aqueous solution
Authors: Rahman Mohammad Shahedur
Published: July 2022

Oak species are a successful plant group that have colonized the world's largest areas of forest. Oak trees are also prevalent in urban green spaces in the United States and Canada. As a result, these trees produced an abundance of acorns each year. In urban areas, these acorns are frequently discarded as solid waste. Alternative uses for this forest/plant waste are highly desirable because they will not only be valorized but will also contribute to the reduction of solid waste. The purpose of this work was to manufacture low-cost activated carbon using Red Oak (Quercus rubra) acorns and utilize it to remove methyl blue colors in aqueous solutions. The results of experiments indicated that prepared carbons were effective at removing pollutants from water. The pH, starting dye concentration, temperature, duration of the adsorption process, and shaking rate all had an effect on the adsorption process. The basic pH system was found to have the most favourable conditions for dye removal after a 3-hour contact time. The starting concentration of adsorbate has a detrimental influence on the removal rate, while the other factors also may have effect. A kinetic analysis revealed for the first 2 hours, the dye adsorption was better characterized by a pseudo-second order kinetic model with an equilibrium concentration (qe) of 0.9756 mg/g and an equilibrium rate constant (k2) of 16.81 g/mg min. Given that Red Oak acorns are largely regarded as solid waste due to their low monitory value and their widespread availability, the resulting carbons are anticipated to be economically feasible for the treatment of wastewater. The study's various findings indicate that this novel material is an excellent biosorbent for dye removal from contaminated waters.
Dynamic Analysis of High-Rise Structures with Outrigger Structural System Subjected To Lateral Loads
Authors: Shareef Mohammed Sanaullah , Manzoor Khaja Musab , Muqeem Mohammed
Published: July 2022

In this age of urban development and rapid modernization the need of high-rise structures is rapidly increasing as buildings have gotten taller and narrower, the structural engineering has been increasingly challenged to meet the desired stability requirements. In tall buildings, stiffness is the key to sustainability, among various types of structural systems available for tall buildings, outrigger system is one of the majorly used efficient system. The present study aims to identify the efficiency of outrigger shear walls and to find out the optimum position of outriggers in high rise structures under lateral loads. The outrigger systems are required to have additional stiffness and adequate damping, by which outrigger can be used as a structural fuse to protect the building under severe earthquake and wind conditions.

This research work aims to study the dynamic analysis of high-rise structures with outrigger structural system, for this research two regular buildings of 36 & 50 storeys situated in seismic zone V having a constant area of 900sqm(30mx30m) with a typical storey height of 3m were analysed using ETABS 2018. Optimum position of outrigger is determined by considering 8 models in which positions of outriggers is varied along the building height. Response spectrum analysis is carried out to evaluate the performance of structure for earthquake loads and the Gust factor method is used for the dynamic analysis of wind loads. Parameters such as Modal Mass Participation, Base Shears, Storey Displacements, Storey Drift, Time-periods, and acceleration are compared. Upon comparison it was found that among all 36 storey models outriggers placed at extreme ends performed better than other models and among all 50 storey models’ outriggers placed at regular intervals has performed better to all other models.
Developing of lightweight concrete sandwich wall panels with good thermal insulation properties for sustainable buildings
Authors: El Gamal S , Al Saadi S
Published: July 2022

This research study aims at developing and investigating the mechanical and thermal properties of lightweight sandwich wall panels with good thermal insulation properties to reduce electric power for cooling of buildings. Within this study, several thermal insulation sandwich wall panels with two outer lightweight concrete layers and inner expanded polystyrene layer were developed and tested. Test parameters included the type of the outer concrete layers and the effect of using glass fiber reinforced polymer (GFRP) shear ties to connect the outer layers. Different ratios of polystyrene beads and vermiculite aggregates (53, 68 and 84% by volume of the natural coarse aggregates) were used to replace the natural coarse aggregates in the two outer concrete layers for better insulation properties and to develop lighter panels. Test results showed that using the GFRP shear ties was effective to connect the two outer layers of the panels. The results also revealed that increasing the amount of the polystyrene beads and the vermiculite aggregates decreased the thermal conductivity, the density, and the compressive strength of the panels. These values ranged from 0.41 to 0.25 W/m.K, 596 to 486 kg/m3, and 4.21 to 2.02 MPa respectively, for the panels with polystyrene beads. For the panels with vermiculite aggregates, these values were 0.46 to 0.34 W/m.K, 646 to 626 kg/m3, and 3.14 to 1.96 MPa, respectively. The results showed that the panels with polystyrene beads were stronger, lighter, and had better thermal properties. Using the developed panels will help to reduce the self-weigh of buildings resulting in smaller structural elements. In addition, the excellent thermal properties of the developed panels are expected to reduce power consumption and develop more sustainable buildings.
Engineering Properties of Mortar Containing Calcined Local Clay as a Supplementary Cementitious Material
Authors: Meddah M S , Al-Owaisi M S , Hago A W
Published: July 2022

The use of natural and artificial cementitious and pozzolanic materials is gaining importance and become an essential component in today's cement-based materials. Supplementary cementitious materials are recognized to provide an added value to concrete/mortar both for mechanical and durability performances as well as to their sustainability with reduced environmental impacts of the construction industry. Developing locally produced natural pozzolans is vital in the efforts towards enhancing the construction industry's sustainability. Locally extracted raw soil from Nizwa city (NZS) in Oman was ground, calcined, characterized, and used at 10%, 25%, 35%, and 50% as partial replacement of ordinary Portland cement (OPC) in mortar mix. The blend mortar was assessed with regard to compressive strength and durability properties. The obtained results indicate a slight reduction in the flow of the blended mixes. An insignificant effect of the NZS replacement on the hardened mortar's density was observed while slightly reduced strength at 1-day and 28-day for some replacement levels. Meanwhile, around a 1% reduction in the porosity and absorption. Blended cement mortar with NZS demonstrated adequate resistance to sulphuric acid and (sulphate + chloride) exposure with lower weight and strength losses compared to the control mortar.
To Identify the Challenges of Fiscal Policy for Construction Industry in Pakistan
Authors: Farooq Shoail , Khahro Shabir Hussain , Ali Tauha Hussain , Memon Zubair Ahmed
Published: July 2022

The entire influence of a country's budget outcome on economic activity is referred to as fiscal policy. Fiscal policy has its own share of benefits & challenges in particular groups. Therefore, the aim of this study is to identify the benefits & challenges of Fiscal Policy for Construction industry. A detailed literature review has been conducted to identify the possible benefits and key challenges to better fiscal policy. In later stage, a set of questionnaire was prepared using the identified factors. The data was collected from construction industry professionals with experience on fiscal policy management. The data was analysed by aggregated average mean using SPSS. The factor ranks were made on the higher values of aggregated mean value. The study concludes that the main hurdles to better fiscal policy are import/export restrictions, delays in land/plot permits/licenses, and currency fluctuations, as well as government subsidies on construction materials. Similarly, the top benefits for better fiscal policy in the construction industry include meaningful salaries/wages and employment for daily wage earners. The study recommended that, Policymakers must be urged to adopt suitable fiscal policies that address these challenges in order to evolve and improve the construction sector.
Benefits Realization and Application Challenges of Green Concrete Towards Sustainability in Saudi Arabian Construction
Authors: Altarrazi A M , Islam M S , Ghaithan Ahmed M.
Published: July 2022

In recent years, Carbon Dioxide (CO2) emission has been increased by 22% in Saudi Arabia, and the building construction sector is one of the major contributors to increased CO2. This necessitates Saudi Arabia's introduction of energy efficiency and sustainability in the construction sector. Green Concrete (GC) has recently gained popularity in the Kingdom as it is environmentally friendly and produced from waste and residual materials. However, every new technology faces application challenges that can stymie its adoption in the industry. As a result, this study aims to determine the potential benefits and application challenges of using GC technology in Saudi Arabian's construction industry. This study conducted a comprehensive literature review of the subject followed by a questionnaire survey to field practitioners and interviews with professional experts to determine the potential benefits and application challenges of GC technology. In addition, an analysis of GC trail test documents implemented in a local project and a meeting with the project team were also conducted to determine the trial test's advantages and implementation challenges. The major benefits identified in this study are reduced energy use, waste material reuse, CO2 reduction, natural resource conservation, and reduced landfill numbers, while the major implementation challenges identified in this study are discouraging building codes and a lack of information and understanding of GC benefits. Subsequently, recommendations for government agencies, private sector businesses, and concrete suppliers are provided to improve the benefits of GC, resolve application challenges, and promote and accelerate its adoption in Saudi Arabia.
Climatic impact on Rainfall Analysis in Al-Madinah Munawwara Region
Authors: Aldrees A
Published: July 2022

Long-term changes in temperature and weather patterns are referred to as climate change. Climate change and rainfall distribution are inextricably linked to arid and semi-arid regions. Saudi Arabia is entirely located in arid and semi-arid areas, and the arid climate that covers the majority of Saudi Arabia is typically characterized by large temporal and spatial variations in rainfall distribution. The availability of long-term rainfall depth records would be beneficial for studying the impact of climate change. This study aimed to assess the impact of climate change on rainfall analysis based on rainfall data generated by the HYFRAN-PLUS model during 1960–1990 and 1990–2020. Four rain-gauge stations near the Al-Madinah Munawwara region, namely Al Faqir, Umm Al Birak, Madinah Monawara, and Bir Al Mashi, were chosen for statistical analysis. The 1990–2020 rainfall data showed a significant climate change impact on the rainfall analysis at the Umm Al Birak station that was greater than that of the 1960–1990 data. The results of this study provide useful information for water resource planners and urban engineers to assess water availability and create appropriate storage systems considering climate change since 1960.
Sustainable Alternatives for Green Mortar: Quarry Waste and Ultra high fly ash utilization
Authors: Zafar I
Published: July 2022

The use of waste materials from different industries as a replacement of cement has gained much attention all over the world. In addition, many attempts have been done to replace partially or totally one of the ingredients from the mix design to lower the negative impacts of construction industry. In this study, quarry waste and fly ash were used as two different sustainable approaches to replace the maximum volume of natural alluvial sand and cement, respectively, in the traditional mortar matrix. The quarry waste is a by-product of quarries characterized with a large volume of fines, whereas, fly ash is the by-product of coal-fired electric generation plants. The performance of the green mortars containing the maximized volume of quarry waste and fly ash were evaluated with regard to the mechanical properties. The results have clearly indicated the beneficial use of the quarry waste and fly ash as a substitute for siliceous sand and cement respectively in preparation of green mortars. In addition, the cost and parametric analysis was also performed for a multi-story reinforced concrete building using the designed quarry sand and fly ash as concrete ingredients.
Smart Planning of Waste Management System in Saudi Arabia; Challenges and Opportunities
Authors: Alqahtani F K , Alswailem Y K , Alshabragi A M , Sherif M A
Published: July 2022

Solid waste management is one of the most critical problems facing urban areas worldwide. It is quickly becoming a significant issue in emerging countries with high population growth. Waste collection is a time-consuming procedure requiring enormous sums of money and meticulous logistics management. The amount of household waste produced in Riyadh has fluctuated over the years, with the majority being dumped in landfills instead of using them. This inefficient method of waste disposal has several adverse financial and environmental consequences, as landfills take up a large area of the city and emit foul odors and infections. An innovative waste management system should be adopted to address these difficulties, beginning with waste reduction and trash disposal in modern engineered landfills. Waste management solutions include reducing, reusing, recycling, energy recovery, and disposal. This research will focus on recycling, recovery, and disposal since social awareness campaigns could implement the first two strategies to reduce and reuse waste. The analysis also gives a sufficient cost analysis for the proposed methodology. This study opens new avenues for incorporating the value recovery aspect into garbage collection planning and the use of new data capture technologies that allow municipalities to track the mix of recyclables contained in various trash systems.
Solid Waste Assessment and Management Using Remote Sensing Data and GIS Tools: A Case Study of Najran City, KSA
Authors: Elkhrachy Ismail
Published: July 2022

Municipal Solid Waste (MSW) management is a major socio-economic issue in all emerging countries. Cities have their solid waste management regulations, approach, and procedures. They believe that wastelands outside of cities are the greatest places to dispose of solid waste. Such inappropriate location will lead to morphologic changes in the urban region and its surrounding, creating health hazards. The acquisition of data about an object(s) without establishing contact with it is known as remote sensing. The geographic information system (GIS) is a spatial system that creates, maintains, analyses, and maps various kinds of data. GIS software and remote sensing data are extremely valuable for assessing and managing solid wastage. Sentinel-2 satellite images were used to obtain land cover data. Digital elevation model (DEM) from ALOS-PALSAR free data used to describe surface information. Some thematic layers, such as soil, surface slope, drainage density, airport distance, road distance, and land-use, were used as principal input data for Multi-Criteria Decision Analysis (MCDA) to choose the best solid waste locations in Najran city. According to the appropriateness degree of the landfill, locations acquired, 31% and 10.9 percent of the total area were classed as very low and low, respectively, while 25.3 % and 11.9 % were classified as high and very high suitable areas.