bluuebunny/crossref_metadata_2025 huggingface dataset:
Operative Anatomy of the Skull Base: 3D Exploration with a Highly Detailed Interactive Atlas
Authors: Kockro Ralf A. , Schwandt Eike , Ringel Florian , Eisenring Christian Valentin , Nowinski Wieslaw Lucjan
Published: June 2021

Objective We evaluated the usefulness of a three-dimensional (3D) interactive atlas to illustrate and teach surgical skull base anatomy in a clinical setting.

Study Design A highly detailed atlas of the adult human skull base was created from multiple high-resolution magnetic resonance imaging (MRI) and computed tomography (CT) scans of a healthy Caucasian male. It includes the parcellated and labeled bony skull base, intra- and extracranial vasculature, cranial nerves, cerebrum, cerebellum, and brainstem. We are reporting retrospectively on our experiences with employing the atlas for the simulation and teaching of neurosurgical approaches and concepts in a clinical setting.

Setting The study was conducted at the University Hospital Mainz, Germany, and Hirslanden Hospital, Zürich, Switzerland.

Participants Medical students and neurosurgical residents participated in this study.

Results Handling the layered graphical user interface of the atlas requires some training; however, navigating the detailed 3D content from intraoperative perspectives led to quick comprehension of anatomical relationships that are otherwise difficult to perceive. Students and residents appreciated the collaborative learning effect when working with the atlas on large projected screens and markedly improved their anatomical knowledge after interacting with the software.

Conclusion The skull base atlas provides an effective way to study essential surgical anatomy and to teach operative strategies in this complex region. Interactive 3D computer graphical environments are highly suitable for conveying complex anatomy and to train and review surgical concepts. They remain underutilized in clinical practice.
Associations of the Neighborhood Built Environment with Gestational Weight Gain
Authors: Grobman William A. , Crenshaw Emma G. , Marsh Derek J. , McNeil Rebecca B. , Pemberton Victoria L. , Haas David M. , Debbink Michelle , Mercer Brian M. , Parry Samuel , Reddy Uma , Saade George , Simhan Hyagriv , Mukhtar Farhana , Wing Deborah A. , Kershaw Kiarri N. ,   for the NICHD nuMoM2b NHLBI nuMoM2b Heart Health Study Networks
Published: June 2021

Objective This study aimed to determine whether specific factors of the built environment related to physical activity and diet are associated with inadequate and excessive gestational weight gain (GWG).

Study Design This analysis is based on data from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be, a prospective cohort of nulliparous women who were followed from the beginning of their pregnancies through delivery. At each study visit, home addresses were recorded and geocoded. Locations were linked to several built-environment characteristics such as the census tract National Walkability Score (the 2010 Walkability Index) and the number of gyms, parks, and grocery stores within a 3-km radius of residential address. The primary outcome of GWG (calculated as the difference between prepregnancy weight and weight at delivery) was categorized as inadequate, appropriate, or excessive based on weight gained per week of gestation. Multinomial regression (generalized logit) models evaluated the relationship between each factor in the built environment and excessive or inadequate GWG.

Results Of the 8,182 women in the analytic sample, 5,819 (71.1%) had excessive GWG, 1,426 (17.4%) had appropriate GWG, and 937 (11.5%) had inadequate GWG. For the majority of variables examined, built environments more conducive to physical activity and healthful food availability were associated with a lower odds of excessive or inadequate GWG category. For example, a higher number of gyms or parks within 3 km of a participant's residential address was associated with lower odds of having excessive (gyms: adjusted odds ratio [aOR] = 0.93 [0.89–0.96], parks: 0.94 [0.90–0.98]) or inadequate GWG (gyms: 0.91 [0.86–0.96]; parks: 0.91 [0.86–0.97]). Similarly, a higher number of grocery stores was associated with lower odds of having excessive GWG (0.94 [0.91–0.97]).

Conclusion Among a diverse population of nulliparous women, multiple aspects of the built environment are associated with excessive and inadequate GWG.

Key Points
Analytical studies of the magnetic domain wall structure in the presence of non-uniform exchange bias
Authors: Kao Yee-Mou , Horng Lance , Cheng Chi-Ho
Published: June 2021

The pinning phenomena of the domain wall in the presence of exchange bias are studied analytically. The analytic solution of the domain wall spin configuration is presented. Unlike the traditional solution, which is symmetric, our new solution could exhibit the asymmetry of the domain wall spin profile. Using the solution, the domain wall position, its width, its stability, and the depinning field are discussed analytically.
The role of traps in dark current and photocurrent of chemical bath deposition grown nano-domains PbS/GaAs heterojunction layers
Authors: Grosman Arieh , Manis Levy Hadar , Sarsui Gabby
Published: June 2021

Lead sulfide (PbS) nano-domain (ND) thin layers were grown by a chemical bath deposition technique on a heavily doped n-type GaAs substrate forming a heterojunction. The PbS NDs' absorption was blue shifted from its original wavelength due to the quantum confinement effect (by controling their sizes below the Bohr radius) to sense short wavelength infrared (SWIR) light (ranging between 1200 and 1800 nm). In order to assess the electrical properties of the PbS ND based layers to be used as a SWIR detector, we performed electrical measurements that included current–voltage (I–V), capacitance–voltage (C–V), electron impedance spectroscopy (EIS), and transmission electron microscopy (TEM). The I–V measurements showed hysteresis behavior that was found to be imposed by the high trap concentration within the PbS NDs and at the layer interfaces. The hysteresis that was demonstrated during the electrical measurement is explained by the slow filling of the trap within the PbS ND thin layer. In order to reduce the trap density, we performed a thermal treatment at 150°C for 30 min prior to the electrical measurements. Using C–V measurements, we expected to find a reduction in the capacitance due to the decrease of the trap density after the thermal treatment. However, we discovered an increase in the capacitance, where temperature-dependent I–V measurements revealed an additional slow charging mechanism in series with the heterojunction. We found that this can be attributed to the generation of a thin isolation layer at the interface between the PbS-NDs layer and the GaAs substrate that also contains interface traps induced by the thermal treatment that was performed in an air atmosphere. We corroborated our assumption by performing EIS measurements and TEM analysis, which showed the generation of a thin isolation layer at the PbS/GaAs interface.
Piezoelectric properties of substitutionally doped β-Ga2O3
Authors: Li Lijie
Published: June 2021

Modern semiconductor materials are increasingly used in multidisciplinary systems demonstrating cross-interactions between mechanical strains and electronic potentials, which gives rise to ubiquitous applications in high sensitivity, self-powered sensor devices. One of the fundamental prerequisites for such semiconductor materials to exhibit piezoelectric properties is the noncentrosymmetry of the crystal structures. β-Ga2O3 has been an emerging compound semiconductor material due to its ultra-wide bandgap. However, pristine β-Ga2O3 has an inversion center, displaying no piezoelectric effect. This work discovered that substitutionally doped β-Ga2O3 possesses piezoelectric property by using the first principles method, while a majority of previous research on its substitutional doping has been focused on the purposes of increasing electrical conductivity and formation of semiconductor heterojunctions. More interestingly, it is unveiled from this work that the formation energy has a clear relation with the piezoelectric coefficient.
Equilibrium analysis of Mott memristor reveals criterion for negative differential resistance
Authors: Sarles Stephen A. , Wright Joseph P. , Pei Jin-Song
Published: June 2021

Two-terminal electronic devices that exhibit voltage-controlled threshold switching (TS) via negative differential resistance (NDR) are important for many emerging applications. Pickett and Williams developed what has become a well-known physics-based model for nanoscale devices exhibiting NDR due to a reversible insulator-metal phase (Mott) transition. The Mott memristor model couples changes in electrical resistance and Joule heating to the phase of the material using one dynamic state variable, u, that describes the volume fraction of metal in the cross section of the device. The model formulation involves one nonlinear first-order ordinary differential equation and eight physical parameters. New equilibrium analysis reveals a simple condition that determines whether the model predicts NDR required for current–voltage (i–v) hysteresis in a voltage-controlled operation. We show that S-shaped NDR (also called current-controlled NDR) arises only above a critical ratio, Mc, of insulator to metal resistivity. Specifically, hysteresis in the i–v plane cannot occur below Mc=e2+1≈8.39 (i.e., e≈2.718…; Euler's number), but above this value hysteresis appears. This understanding enables tuning of hysteretic features, including threshold voltages for resistive switching, which benefit the use of TS memristors as memory storage elements, as well as excitable devices mimicking neural action potentials.
Dynamical correlation energy of metals in large basis sets from downfolding and composite approaches
Authors: Callahan James M. , Lange Malte F. , Berkelbach Timothy C.
Published: June 2021

Coupled-cluster theory with single and double excitations (CCSD) is a promising ab initio method for the electronic structure of three-dimensional metals, for which second-order perturbation theory (MP2) diverges in the thermodynamic limit. However, due to the high cost and poor convergence of CCSD with respect to basis size, applying CCSD to periodic systems often leads to large basis set errors. In a common “composite” method, MP2 is used to recover the missing dynamical correlation energy through a focal-point correction, but the inadequacy of finite-order perturbation theory for metals raises questions about this approach. Here, we describe how high-energy excitations treated by MP2 can be “downfolded” into a low-energy active space to be treated by CCSD. Comparing how the composite and downfolding approaches perform for the uniform electron gas, we find that the latter converges more quickly with respect to the basis set size. Nonetheless, the composite approach is surprisingly accurate because it removes the problematic MP2 treatment of double excitations near the Fermi surface. Using this method to estimate the CCSD correlation energy in the combined complete basis set and thermodynamic limits, we find that CCSD recovers 85%–90% of the exact correlation energy at rs = 4. We also test the composite approach with the direct random-phase approximation used in place of MP2, yielding a method that is typically (but not always) more cost effective due to the smaller number of orbitals that need to be included in the more expensive CCSD calculation.
Reduction of metal oxides using thermogravimetry under microwave irradiation
Authors: Fujii Satoshi , Yamamoto Masahiro , Haneishi Naoto , Tsubaki Shuntaro , Fukushima Jun , Takizawa Hirotsugu , Wada Yuji
Published: June 2021

Chemical reactions performed under microwave irradiation often demonstrate high reaction rates, high selectivity, and low reaction temperatures, which allows for more compact reactors and more energy-efficient processes than used in conventional heating methods. In this study, we discovered a new chemical reaction and proposed a new material synthesis method, performed using a solid-state microwave source with an oscillator and a single-mode cavity. We developed a microwave heating thermogravimetry apparatus to confirm that microwave irradiation reduced the temperature of the reduction process. Next, we applied this apparatus to the reduction process of copper oxide with carbon as the reducing agent and compared microwave heating with conventional heating. We demonstrated that the reduction temperature of microwave heating was 192 °C in a magnetic (H) field and 265 °C in an electric (E) field, which were lower than those of conventional heating. For microwave heating in the E-field, plasma strongly affected the reaction process, leading to a reduction in the reaction temperature. For microwave heating in the H-field, localized heating occurred and the average reaction temperature was lower. Using the obtained results, an applicator suitable for these modes can be designed, enabling a reduction process with an additional energy-saving effect.
A practical Tamm plasmon sensor based on porous Si
Authors: Juneau-Fecteau Alexandre , Savin Rémy , Boucherif Abderraouf , Fréchette Luc G.
Published: June 2021

We report the fabrication and characterization of a new type of porous Si sensor using the Tamm plasmon resonance. The sensor consists of a photonic crystal created by periodic electrochemical anodization of crystalline Si, followed by partial thermal oxidation. The photonic crystal is transferred to a Au-coated glass substrate to allow optical measurements of surface modes at the metal/porous Si interface. This configuration greatly simplifies sensing since an analyte can be introduced in the pores from the opposite side of the metal layer without disrupting the optical path. The fabricated device exhibits a Tamm plasmon resonance within the photonic bandgap at a wavelength of 794 nm with a quality factor of 25. We observe a wavelength shift of the resonance when the nanosized pores are infiltrated with different concentrations of a toluene/ethanol solution. The measured sensitivity reaches 139 nm/RIU, in agreement with scattering matrix simulations and more than twice larger than those previously reported for Tamm plasmons. The quality factor and sensitivity yield a sensor figure of merit of 4. We also show that the electric field within the Tamm device is confined within a mode volume twice smaller than within a Fabry–Pérot resonator of comparable size according to calculations.
Suppression of low-frequency pressure pulsations in an open jet wind tunnel by corner vortex generators
Authors: Jin Ling , Sun Haisheng , Jiang Yubiao , Liang Yong , Zhang Junlong
Published: June 2021

Suppression of low-frequency pressure pulsations using vortex generators at the jet nozzle is investigated for a large low-speed open jet wind tunnel. The pressure pulsations are measured for different arrangements of the vortex generators at the jet nozzle. It is found that only generators installed at the corners of the nozzle can reduce low-frequency pressure pulsations and generators installed in the middle parts of the four inner walls of the nozzle not only fail to decrease the pulsations but also excite them outside the jet even more strongly. On the basis of these results, corner vortex generators (CVGs) are adopted for control of low-frequency pressure pulsations in the open jet wind tunnel. After installation of CVGs, both the amplitude of pressure pulsations in the plenum and the turbulence intensity at the center of the test section are significantly reduced.
Downscaled GCM climate projections of fire weather over Victoria, Australia. Part 1
Authors: Clark Scott , Mills Graham , Brown Timothy , Harris Sarah , Abatzoglou John T.
Published: June 2021

Anthropogenic climate change is expected to cause an increase in fire danger over south-eastern Australia during the 21st century, primarily driven by increased surface temperature. Studies of future fire weather in Victoria, Australia, have so far mostly utilised direct output from general circulation models, which have inadequate resolution for resolving the dynamics of local fire danger and are prone to substantial biases that may affect the seasonality of dry fuels. In this paper, we assess the ability of the Multivariate Adaptive Constructed Analogs (MACA) method to downscale output from general circulation models over Victoria, and replicate statistical attributes of fire danger indices. We find that climatological descriptors of meteorological variables of wind, temperature and humidity are captured extremely well, and fields on extreme fire days are well captured. We find that the method works very well for statistically downscaling fire weather elements over Victoria and provides a vehicle to assess the regional variation of fire weather projections over Victoria.
Downscaled GCM climate projections of fire weather over Victoria, Australia. Part 2
Authors: Clark Scott , Mills Graham , Brown Timothy , Harris Sarah , Abatzoglou John T.
Published: June 2021

This paper applies the Multivariate Adaptive Constructed Analogs (MACA) statistical downscaling method to 12 general circulation models to produce 21st century projections of fire weather variables over Victoria, Australia, under two emissions scenarios. The statistically downscaled model data accurately replicate the observed distributions of meteorological variables over the contemporary period, but underestimate fire danger extremes in some models. Under each climate scenario, both mean and extreme fire danger are expected to increase. Though there is variation across Victoria, the 12-model average by year for RCP8.5 indicates a 10–20% increase in extreme (99th percentile) Forest Fire Danger Index across the state, with the greatest change projected in the north-west region. At five geographically and climatologically different locations across Victoria, there is a 50–200% increase in the number of days per year exceeding the threshold for the Victorian Very High or higher fire danger rating by the end of the century compared with the start. The high-end warming (RCP8.5) scenario shows increased temperature to be the main driver of heightened fire danger. Changes in temperature, humidity and precipitation during spring and early summer both increase the length of the fire season and may reduce springtime opportunities for prescribed burning.
Developmental influence on evolutionary rates and the origin of placental mammal tooth complexity
Authors: Couzens Aidan M. C. , Sears Karen E. , Rücklin Martin
Published: June 2021

Significance

Interactions during development among genes, cells, and tissues can favor the more frequent generation of some trait variants compared with others. This developmental bias has often been considered to constrain adaptation, but its exact influence on evolution is poorly understood. Using computer simulations of development, we provide evidence that molecules promoting the formation of mammalian tooth cusps could help accelerate tooth complexity evolution. Only relatively small developmental changes were needed to derive the more complex, rectangular upper molar typical of early placental mammals from the simpler triangular ancestral pattern. Development may therefore have enabled the relatively fast divergence of the early placental molar dentition.
A catalog of tens of thousands of viruses from human metagenomes reveals hidden associations with chronic diseases
Authors: Tisza Michael J. , Buck Christopher B.
Published: June 2021

Significance

Mechanisms of many human chronic diseases involve abnormal action of the immune system and/or altered metabolism. The microbiome, an important regulator of metabolic and immune-related phenotypes, has been shown to be associated with or participate in the development of a variety of chronic diseases. Viruses of bacteria (i.e., “phages”) are ubiquitous and mysterious, and several studies have shown that phages exert great control over the behavior—and misbehavior—of their host bacteria. This study uses techniques to discover and analyze over 45,000 viruses associated with human bodies. The abundance of over 2,000 specific phages is found to correlate with a variety of common chronic diseases.
A combination of Class-I fumarases and metabolites (α-ketoglutarate and fumarate) signal the DNA damage response in
Escherichia coli
Authors: Silas Yardena , Singer Esti , Das Koyeli , Lehming Norbert , Pines Ophry
Published: June 2021

Significance

Class-II fumarases have been shown to participate in cellular respiration and the DNA damage response. Here, we show that in the model prokaryote,
Escherichia coli
, which harbors both class-I and class-II fumarases, it is the class-I fumarases that participate in DNA damage repair by a mechanism that is different from those described for other fumarases. Strikingly, this mechanism employs a signaling molecule, alpha-ketoglutarate (α-KG), and its target is the DNA damage repair enzyme AlkB. In addition, we show that the fumarase precursor metabolites, fumarate and succinate, can inhibit the α-KG–dependent DNA damage repair enzyme, AlkB, both in vitro and in vivo. This study provides a perspective on the function and evolution of metabolic signaling.
Kinetoplastid kinetochore proteins KKT2 and KKT3 have unique centromere localization domains
Authors: Marcianò Gabriele , Ishii Midori , Nerusheva Olga O. , Akiyoshi Bungo
Published: June 2021

The kinetochore is the macromolecular protein complex that assembles onto centromeric DNA and binds spindle microtubules. Evolutionarily divergent kinetoplastids have an unconventional set of kinetochore proteins. It remains unknown how kinetochores assemble at centromeres in these organisms. Here, we characterize KKT2 and KKT3 in the kinetoplastid parasite Trypanosoma brucei. In addition to the N-terminal kinase domain and C-terminal divergent polo boxes, these proteins have a central domain of unknown function. We show that KKT2 and KKT3 are important for the localization of several kinetochore proteins and that their central domains are sufficient for centromere localization. Crystal structures of the KKT2 central domain from two divergent kinetoplastids reveal a unique zinc-binding domain (termed the CL domain for centromere localization), which promotes its kinetochore localization in T. brucei. Mutations in the equivalent domain in KKT3 abolish its kinetochore localization and function. Our work shows that the unique central domains play a critical role in mediating the centromere localization of KKT2 and KKT3.
Unusual Normal and Superconducting State Properties Observed in Hydrothermal Fe1-δ
Se Flakes
Authors: Liu Shaobo , Ma Sheng , Wang Zhaosheng , Hu Wei , Li Zian , Liang Qimei , Wang Hong , Zhang Yuhang , Lu Zouyouwei , Yuan Jie , Jin Kui , Li Jian-Qi , Pi Li , Yu Li , Zhou Fang , Dong Xiaoli , Zhao Zhongxian
Published: June 2021

The electronic and superconducting properties of Fe1–δ
Se single-crystal flakes grown hydrothermally are studied by the transport measurements under zero and high magnetic fields up to 38.5 T. The results contrast sharply with those previously reported for nematically ordered FeSe by chemical-vapor-transport (CVT) growth. No signature of the electronic nematicity, but an evident metal-to-nonmetal crossover with increasing temperature, is detected in the normal state of the present hydrothermal samples. Interestingly, a higher superconducting critical temperature T
c of 13.2 K is observed compared to a suppressed T
c of 9 K in the presence of the nematicity in the CVT FeSe. Moreover, the upper critical field in the zero-temperature limit is found to be isotropic with respect to the field direction and to reach a higher value of ∼42 T, which breaks the Pauli limit by a factor of 1.8.
Comparing the effectiveness of learning formats in radiation protection
Authors: van Puyvelde L , Clarijs T , Belmans N , Coeck M
Published: June 2021

At the Belgian Nuclear Research Centre (SCK CEN) more than 850 employees advance the peaceful applications of ionising radiation through research, services and education and training. Several initiatives are taken to guarantee a safe working environment, one of them being a compulsory introductory safety training for all new employees, followed by refresher courses. With the objective to increase the flexibility for the participants and to optimise the teaching time of lecturers, the training format is adapted from face-to-face training to blended learning in which a significant amount of online learning is introduced. To appraise the perception and effectiveness of the original face-to-face training and the newly developed e-learning modules, and to compare both, information is gathered on two levels. Firstly, to monitor the perception of the participants regarding the face-to-face and e-learning formats an online questionnaire was launched. Secondly to evaluate the knowledge gain (difference between pre- and post-test results), the participants were requested to answer the same set of technical/scientific questions before and after the training. Results of the perception study show that the e-learning format was well received by the learners. For both learning formats an overall knowledge gain was noticed. The highest knowledge gain was noticed for the e-learning format. The results on perception and effectivity of the e-learning format confirm the further use of this format.
Effects of Prandtl number in two-dimensional turbulent convection*
Authors: He Jian-Chao , Fang Ming-Wei , Gao Zhen-Yuan , Huang Shi-Di , Bao Yun
Published: June 2021

We report a numerical study of the Prandtl-number (Pr) effects in two-dimensional turbulent Rayleigh–Bénard convection. The simulations were conducted in a square box over the Pr range from 0.25 to 100 and over the Rayleigh number (Ra) range from 107 to 1010. We find that both the strength and the stability of the large-scale flow decrease with the increasing of Pr, and the flow pattern becomes plume-dominated at high Pr. The evolution in flow pattern is quantified by the Reynolds number (Re), with the Ra and the Pr scaling exponents varying from 0.54 to 0.67 and –0.87 to –0.93, respectively. It is further found that the non-dimensional heat flux at small Ra diverges strongly for different Pr, but their difference becomes marginal as Ra increases. For the thermal boundary layer, the spatially averaged thicknesses for all the Pr numbers can be described by δθ
∼ Ra
−0.30 approximately, but the local values vary a lot for different Pr, which become more uniform with Pr increasing.
Evolution of helium bubbles in nickel-based alloy by post-implantation annealing*
Authors: Zhu Rui , Zhou Qin , Shi Li , Sun Li-Bin , Wu Xin-Xin , Lv Sha-Sha , Li Zheng-Cao
Published: June 2021

Nickel-based alloys have been considered as candidate structural materials used in generation IV nuclear reactors serving at high temperatures. In the present study, alloy 617 was irradiated with 180-keV helium ions to a fluence of 3.6 × 1017 ions/cm2 at room temperature. Throughout the cross-section transmission electron microscopy (TEM) image, numerous over-pressurized helium bubbles in spherical shape are observed with the actual concentration profile a little deeper than the SRIM predicted result. Post-implantation annealing was conducted at 700 °C for 2 h to investigate the bubble evolution. The long-range migration of helium bubbles occurred during the annealing process, which makes the bubbles of the peak region transform into a faceted shape as well. Then the coarsening mechanism of helium bubbles at different depths is discussed and related to the migration and coalescence (MC) mechanism. With the diffusion of nickel atoms slowed down by the alloy elements, the migration and coalescence of bubbles are suppressed in alloy 617, leading to a better helium irradiation resistance.
Ion track-based nanowire arrays with gradient and programmable diameters towards rational light management*
Authors: Huang Ran , Zhang Jiaming , Xu Fangfang , Liu Jie , Yao Huijun , Chen Yonghui , Duan Jinglai
Published: June 2021

Integrating nanowires with nonuniform diameter and random spatial distribution into an array can afford unconventional and additional means for modulating optical response. However, experimental realization of such a nanowire array is quite challenging. In this work, we propose a new fabrication strategy which takes advantage of ion track technology, via sequential swift heavy ion irradiation and ion track etching. Based on this strategy, we unprecedentedly realize nanowire arrays, using gold as an example, with gradient and programmable diameters in a controlled manner. We further demonstrate that such nanowire arrays can support broadband, tunable, and enhanced plasmonic responses. We believe that our new type of nanowire arrays will find great potential in applications such as light management and optoelectronic devices.
Thermodynamic criterion for searching high mobility two-dimensional electron gas at KTaO3 interface*
Authors: Shi Wen-Xiao , Zhang Hui , Qi Shao-Jin , Zhang Jin-E , Huang Hai-Lin , Shen Bao-Gen , Chen Yuan-Sha , Sun Ji-Rong
Published: June 2021

Two-dimensional electron gases (2DEGs) formed at the interface between two oxide insulators present a promising platform for the exploration of emergent phenomena. While most of the previous works focused on SrTiO3-based 2DEGs, here we took the amorphous-ABO3/KTaO3 system as the research object to study the relationship between the interface conductivity and the redox property of B-site metal in the amorphous film. The criterion of oxide–oxide interface redox reactions for the B-site metals, Zr, Al, Ti, Ta, and Nb in conductive interfaces was revealed: the formation heat of metal oxide,

Δ

H
f
o

, is lower than –350 kJ/(mol O) and the work function of the metal Φ is in the range of 3.75 eV < Φ < 4.4 eV. Furthermore, we found that the smaller absolute value of

Δ

H
f
o

and the larger value of Φ of the B-site metal would result in higher mobility of the two-dimensional electron gas that formed at the corresponding amorphous-ABO3/KTaO3 interface. This finding paves the way for the design of high-mobility all-oxide electronic devices.
Investigation on threshold voltage of p-channel GaN MOSFETs based on p-GaN/AlGaN/GaN heterostructure*
Authors: Li Ruo-Han , Fei Wu-Xiong , Tang Rui , Wu Zhao-Xi , Duan Chao , Zhang Tao , Zhu Dan , Zhang Wei-Hang , Zhao Sheng-Lei , Zhang Jin-Cheng , Hao Yue
Published: June 2021

The threshold voltage (V
th) of the p-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) is investigated via Silvaco-Atlas simulations. The main factors which influence the threshold voltage of p-channel GaN MOSFETs are barrier height Φ
1,p, polarization charge density σ
b, and equivalent unite capacitance C
oc. It is found that the thinner thickness of p-GaN layer and oxide layer will acquire the more negative threshold voltage V
th, and threshold voltage |V
th| increases with the reduction in p-GaN doping concentration and the work-function of gate metal. Meanwhile, the increase in gate dielectric relative permittivity may cause the increase in threshold voltage |V
th|. Additionally, the parameter influencing output current most is the p-GaN doping concentration, and the maximum current density is 9.5 mA/mm with p-type doping concentration of 9.5 × 1016 cm−3 at V
GS = –12 V and V
DS = –10 V.
Earthen slope stability using dimensional analysis
Authors: Alrammahi Faris S , Abbas Sarmad A , Khassaf Saleh I , Madhloom Huda M , Aljaradin Mohammad
Published: June 2021

Slope stability is an important aspect in the management of civil engineering projects. The stability of earth slopes is a significant concern for safety and the economy. There are several methods for finding the safety factor. Spencer’s method is considered one of the most accurate methods for calculating the factor of safety but it depends on the others on dividing the slope geometry into the number of slices with complicated calculations. This paper introduced a new theoretical equation (using dimensional analysis) capable of defining and testing the slope stability of the natural and man-made slope of the earth without complicated calculations. The major and significant variables which affect and contribute to the stability of a slope will be listed and discussed. The Geo-SLOPE and SEEP software were used to present the stability analyses of the earth dam and compare the result. The derived equation shows the excellent relationship between the factor of safety concerning the ratio of internal friction angle over slope angle ∅/α and the hydraulic gradient. The main objective is to set a new rapid method for checking the stability of slopes instead of a complex calculation that can describe the slope stability of the natural earth slope.
Estimation the components of deflection of the vertical for a point in Baghdad City - Iraq
Authors: Mohammed Israa H. , Ataiwe Tariq N. , Sharaa Hisham Al
Published: June 2021

In the age of the satellite geodesy, the GNSS is widely used in development of geodetic networks and that give much application, for that reason the study is to estimate deflection of the vertical of a point in Baghdad City in Iraq, the estimated depends on the orthometric height, which computed through the levelling and the ellipsoidal height, which computed from the GPS observations. Due to the lack of survey data and the difficulty of taking terrestrial measurements as a result of the security situation the authors used only 5 points for the national network in Baghdad. The deflection of the vertical component component ξ in the north-south direction calculated as ξ=2.5”±0.001” and the prime vertical component η in the east-west direction calculated as η=5.23” ±1.5”. The results were obtained showing that it can calculate the deflection of the vertical at sufficient accuracy.
Important methods measurements to exam the accuracy and reliability of reflector-less total station measurements
Authors: Mohammed Shireen Ibrahim
Published: June 2021

Inaccessible points are difficult to measure because the prism cannot be position in these points, so reflector-less total station has solved this problem and these points can be measured easily. But the vital question is, if these measurements are accurate and reliable. This research has carried out to identify the vital methods measurements that have to be done to identify the reliability and the exact accuracy of the reflector-less measurements. Results are not general for all total station types because each instrument has its own specifications, and the continues use of the instrument (old used instruments) could affect the accuracy of measurements. In the third world countries or in specific in our cities, old version surveying instruments are still used in most projects. In some projects specially in high accuracy projects (such as bridges monitoring by using total station), it is important to know the exact distance that errors are going to be introduced by using reflector less total station (the distance between the target and the instrument). By identifying the limitations, the errors can be avoided, and the required accuracy can be obtained. In this research many observations in different locations are carried out in two situations, the first one by using prism and the second one by using reflector-less mode to compare between them. This study has identified many aspects include: the effects of beam divergence and the incidence angle on the accuracy and reliability of the measurements. In addition, the limitation of the reflector-less technology when the high accuracy is required. Furthermore, it has suggested the solution to this problem. In this research methods measurements to exam the reliability and the exact accuracy of the reflector-less measurements have been identified for total station Topcon ES-103, and these methods could be used to any type of total station before start in any high accuracy project. When the reflector-less measurements limitations are identified, the errors could be avoided.
Synthesis and characterization of a novel polyaniline@ montmorillonite-copper (II) sulfate nanocomposite
Authors: Haasan Eman H , Yousif Qahtan A
Published: June 2021

Polyaniline (PANI) and its nanocomposites (PANI\MMT and PANI\MMT-Cu) were prepared with montmorillonite nanoparticles well as the preparation of nanocomposite polyaniline with adjusted copper sulfate montmorillonite clay. As X-ray fluorescence and X-ray diffraction technology were used to calculate nanocomposite type and crystal sizes of PANI, PANI\MMT, PANI\MMT-Cu, respectively, samples were measured. The FTIR charts revealed new absorption peaks for nanocomposites that varied from polyaniline absorption values, and this is proof of nanocomposite preparation. UV calculations were often used to calculate the overall wavelength, red, and blue shifts. To inspect the morphology of polyaniline and its nanocomposites, FESEM was also carried out.
The effect of sustainable materials on fatigue cracking of thing overlay asphalt mixture
Authors: Almaali Yassir Abo , Al-Busaltan Shakir , Kadhim Mustafa Amoori
Published: June 2021

The life of the pavement affected by several factors that play a main role in the performance of asphalt pavement, one of these factors the failure modes, can be represented the important factors that reduced the service life of flexible pavements. Fatigue cracking failure of all the types of failures modes, it is still considered the most common failure mode in recent years. Improvement the performance of pavement by good field works or by enhancing the properties of HMA mixtures represents the essential target by engineers to reduce the maintenance cost and to mitigate potential safety problems. Therefore, this study aims to assess the effect of polymer modified asphalt (PMA); waste material namely crumb rubber with low density polyethylene (LDPE) were used as a combined admixture or as single additive as a sustainable material to enhance the fatigue properties of thin overlay asphalt mixture. 15% of 250-micron crumb rubber was added, while 2.5, 5, 7.5, and 10 % LDPE were added to produce PMA. The flexural beam fatigue test was performed at temperature of (20 °C) to describe the fatigue life of modified thin overlay asphalt mixtures. Results exhibit the vital role of crumb rubber in increase the fatigue life of the mix as compared to conventional mixtures, while LDPE showed a significant role in increase fatigue life of thin overlay asphalt mixture. Fatigue life increase when the 15% of Crum Rubber Modifiers added to the binder. Also fatigue life increase when low density polyethylene (LDPE) added for a high percentage; from the analysis of the result that asphalt mixtures contain (7.5% and 10%) low density polyethylene (LDPE) in addition of 15% of Crumb Rubber Modifier (CRM) achieved the best fatigue life because of the effect of modifiers properties such as flexibility, elasticity, as well as laboratory conditions. Thus, this emphasis the ability of waste material to enhance the asphalt mixture and upgrade such mixture in a sustainable approach.
Eliciting a mathematical model from the traffic safety index to estimate the number of road traffic accidents
Authors: Neham Sahar S.
Published: June 2021

Traffic accidents have become one of the most important problems experienced by countries, leading to the death or injury of many people and the waste of money, which is supposed to be spent on developmental and economic projects that benefit the entire society. In Iraq with the absence of suitable recording system of (Iraqi Roads Traffic Accident Data) and the lack in the measure of highway safety. Thus, lead to error in the analysis of traffic accidents. The aim of this study is to estimate Road Safety Index value and developing a model related it with Road Traffic Accident. To reach the research aim, parameters of Roadway, traffic, Roadside, Pavement and Miscellaneous, characteristics of ten cities in central and southern Iraq (Baghdad, Babylon, Karbala, Najaf, Qadissiya, Muthanna, Dhi Qar, Wasit, Maysan and Basra) were studied. The results show that the extra increase of Road Traffic Accident can be represented by negative exponential trend in relation with Road Safety Index, at 0.05 level of significance 87.6% of variation in Road Safety Index can be accounted for by exponential relationship with Road Traffic Accident.
Removal of Phosphate from Aqueous Solution by using Natural Coagulant: Optimization Response Surface Methodology (RSM)
Authors: Faraj N K , Abudi Z N
Published: June 2021

This study aims to remove phosphate from synthetic solution using the coagulation-flocculation process by the natural coagulants (Rice Husk (RH), Moringa Oliveira Seed pods (MOSP)) and optimize coagulant conditions using response surface methodology (RSM). The effects of operating conditions like initial concentration (40-80ppm), coagulant dosing (2-3 g/L), and pH of (2-6) were implemented. The coagulation-flocculation was improved utilizing Box–Behnken Design (BBD) under RSM. Quadratic model produced by BBD, with a value of R2 equal to 0.9894 and 0.9808 for RH and MOSC, respectively. The results of RSM show that the optimum operating conditions for the RH coagulant were an initial phosphate concentration of 60ppm, dosing 2g/l, and an initial pH of 4. Which are the same conditions for another coagulant (MOSP) with a difference of dosing 2.5g/l. The main results showed that the coagulants used in this work have a high ability to treat phosphates efficiently instead of using chemicals at a natural pH. The current study shows that it is possible to use RH and MOSP as new natural coagulants that are cost-effective in treating industrial wastewater.
Preparation of edible casings with natural biological characteristics from green tea extract
Authors: Abdulhadi Ihab Mahmood , Shakkak Mahdi Abbas , El-Balloula Maha Fadul Mohammed , Dosh Kifah Saeed
Published: June 2021

In this study, the envelope of whey proteins was fortified with green tea extract, where the effectiveness of green tea extracts was measured in which the aqueous alcohol solution was used at different concentrations as a solvent for the purpose of choosing a specific concentration of the alcohol solution on which the rest of the studies would be conducted in addition to determining the proportions of the extraction relative to the dry matter for each, where the proportions were (aqueous, alcoholic 25%). Alcoholic 50% and alcohol 75%) and the percentages for extraction were respectively (18.6%, 21.33%, 24%, and 25.14%). Where it was found that there is clear effectiveness in inhibiting the growth of E. coli bacteria, and the radial halos measured for the types of concentrations of extracts (aqueous, alcoholic 25%, alcoholic 50%, alcoholic 75%), respectively (24.6, 24.2, 22.8, 11.5 mm). The minimum concentration of inhibition was measured for dry matter and included a group of negative bacteria (Escherichia coli, Salmonella spp.) Furthermore, Gram-positive bacteria (Bacillus spp.), moreover, to the yeast (Candida albican), where the diameters of the halos reached the minimum concentration of inhibition (17.6). 16.6, 10.7, 10.3), respectively. Thecasings fortified with the alcoholic extract of green tea showed a very high antioxidant efficiency compared to the standard concentration of BHA, where the efficacy for them was (69.78% and 30.24%) respectively. Finally, both oxygen and water vapour’s permeability values were measured to find and evaluate the confinementcasings’ properties. The values of the permeability of the control membrane to oxygen reached 92.02 (ml / m2 * day), while the water vapour permeability of thecasings sample supported by the extract decreased to 69.98 (ml / m2 * day).
Evaluation the turbidity removal efficiency in Al-Wahda water treatment plant using statistical indicators
Authors: Saleem A T , Al-Musawi N O
Published: June 2021

Most of drinking water consuming all over the world has been treated at the water treatment plant (WTP) where raw water is abstracted from reservoirs and rivers. The turbidity removal efficiency is very important to supply safe drinking water. This study is focusing on the use of multiple linear regression (MLR) and artificial neural network (ANN) models to predict the turbidity removal efficiency of Al-Wahda WTP in Baghdad city. The measured physico-chemical parameters were used to determine their effect on turbidity removal efficiency in various processes. The suitable formulation of the ANN model is examined throughout many preparations, trials, and steps of evaluation. The prediction models of the turbidity removal are presented. Results found that the estimating of the turbidity removal efficiency by ANN and MLR model could be successful. Moreover, results showed that influent and effluent turbidity concentration have more effect on removal efficiency predicting from the other parameters. Finally, the ANN model could be more accurate than the MLR model according to the coefficient of correlation (0.925).
Effect of geogrid on the structural behavior of reinforced concrete beams
Authors: Yousif Mustafa Ahmed , Mahmoud Kamal Shahada , Hacheem Zuhiar Abd , Rasheed Mohammed Mohammed
Published: June 2021

Now, using of geogrids as strengthening material are extend used, especially to enhancement of concrete elements as inter layers concrete applications, eight beams were tested to explain the effect of geogrid on the behavior of reinforced concrete beams. Beams tested had equal cross-sectional dimension (100 mm x 200 mm), compressive strength (f’c = 30 MPa), with a simply span length equals 1150 mm, with shear reinforcement (Ф4 @100mm C/C) and subjected to two point load. The tested beams were divided into two groups according to the presence of geogrid layer, with and without geogrid. Each group consists of four specimens, which were sub-divided according to the flexural reinforcement ratio that ranges from (0 to 0.0263). During the tests, it was noted that, the load deflection curve for beams with geogrid layer were stiffer and the percentage of stiffening was increased with increase of the flexural reinforcement ratio. The maximum applied load for beams with geogrid layer were higher than conventional beams without geogrid layer under the same conditions, while, the deflection values for beams with geogrid layer was lower than conventional beams without geogrid layer. The first crack load of beams with geogrid was greater than conventional beams without geogrid layer. So, the geogrids layer offer great enhancements to concrete properties and performance from the first cracking load, load-deflection response, reduce the cracks width and number and ultimate strength of tested in comparison to the conventional beams.
Numerical investigation of shear reinforcement effects on the flexural behavior of reinforced concrete beams
Authors: Al-jamel Ameer A. N. , Al-Mutairee Hayder M.K.
Published: June 2021

The aim of this article is to study the effects of lateral reinforcement on the flexural behaviour of Straight Reinforced Concrete (RC) Beam by Finite Element Method (FEM). Three-dimensional nonlinear finite element analyses was performed for simply and fixed supported beams utilizing computer program called NFHCBSL, this program incorporates 20-node isoparametric brick element that is used to represent the concrete elements while reinforcing bars are idealized as axial members embedded within the concrete elements without any relative displacement between them. Different flexural reinforcement ratios, stirrups spacing, depth to width ratios (h/b), and shear span to depth ratios (a/h) have been studied. The failure of all specimens is designed to be by flexure. The results have shown that the most increments in ultimate load with increasing shear reinforcement were found for ratios of ρprov./ρmax larger than 80% for h/b less than or equal to 2, while the increments were near to 9% when the stirrups increased by 100%. Also, for h/b is equal to 2.5 the optimal efficiency of stirrups on the ultimate load was at ρprovided/ρmax equal to 43. The increments in the ultimate loads were 20% and 33% when the stirrups increased by 50% and 100% respectively.