bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of n-GaN cap layer doping on the gate leakage behavior in AlGaN/GaN HEMTs grown on Si and GaN substrates
Authors: Kotani Junji , Yaita Junya , Yamada Atsushi , Nakamura Norikazu , Watanabe Keiji
Published: June 2020

The gate leakage characteristics of n-GaN- and i-GaN-capped AlGaN/GaN high-electron-mobility transistor (HEMT) heterostructures grown on various substrates of Si, SiC, and GaN were investigated. HEMT heterostructures were grown by metal-organic vapor phase epitaxy, and the effect of n-GaN cap layer doping on the gate leakage characteristics was investigated depending on the dislocation densities. For i-GaN capped HEMT heterostructures grown on GaN substrates, the current–voltage characteristics were well explained by the theoretical calculation based on thermionic emission, thermionic-field emission, and field emission. Alternatively, for the AlGaN/GaN HEMT heterostructures grown on Si substrates that contain a high threading dislocation density of 8.2 × 109 cm−2, a drastic increase in the reverse leakage current of approximately five orders of magnitude was observed compared to the reverse leakage current observed for the i-GaN-capped HEMT heterostructures. Conductive atomic force microscope analysis revealed that the dislocation-induced surface pits acted as leakage paths only for the n-GaN-capped HEMT heterostructures. Furthermore, the temperature dependence of the leakage current through the surface pit was investigated using a conductive AFM system, and the temperature-dependent behavior associated with one-dimensional variable-range-hopping (1D-VRH) was confirmed. These results indicate that the surface pits have a large impact on the leakage characteristics of the n-GaN capped structures with high dislocation density, and the electron transport through dislocations based on 1D-VRH plays an important role. Furthermore, we demonstrated a significant reduction in the reverse leakage current for n-GaN-capped AlGaN/GaN HEMT heterostructures using low-dislocation-density GaN substrates, i.e., by reducing dislocation-induced leakage paths. Therefore, we believe that the HEMT heterostructures grown on GaN substrates have an advantage in suppressing frequency dispersion and current collapse with minimized impact on the gate leakage behavior of the Schottky-gated HEMTs with an n-GaN cap layer.
Striped superlattice pattern in dielectric barrier discharge
Authors: Feng Jianyu , Pan Yuyang , Li Caixia , Liu Binbin , Dong Lifang
Published: June 2020

We report on the striped superlattice pattern in dielectric barrier discharge for the first time. The spatiotemporal structure of the striped superlattice pattern is investigated by a high-speed framing camera. The result shows that the striped superlattice pattern consists of three different transient sub-lattices which are striped-dots, stripes, and small-dots surrounding a striped-dot, respectively. Images of a single frame indicate that the stripes which look like they are diffused are actually made up of individual filaments. The optical emission spectra of different sub-lattices are collected and investigated; it is found that plasma parameters of the three different transient sub-lattices are different. The formation mechanism of the striped superlattice pattern is discussed. And a tunable plasma photonic crystal with one and two-dimensions structures which has the dynamic controllability based on the striped superlattice pattern is present.
Review highlights the benefits of quantum optimal control for quantum sensing
Authors: Mandel Savannah
Published: June 2020

Quantum optimal control with nitrogen-vacancy centers in diamond allows researchers to improve quantum sensing technology.
Precursor for atomic layer deposition helps grow molybdenum oxides selectively
Authors: Patrick Chris
Published: June 2020

Using MoCl 4 O to grow molybdenum oxides by atomic layer deposition creates opportunities for area-selective processing.
Measuring chaos by entropy for a finite family of functions
Authors: Korczak-Kubiak Ewa , Loranty Anna , Pawlak Ryszard J.
Published: June 2020

In this paper, we consider chaos of a finite family of continuous functions. As a measure of chaos, we use three types of entropies defined for that family. The first type of entropy is connected with the entropy of semigroups while the second and the third type concern entropy of nonautonomous dynamical systems. The main aim of the paper is to analyze the local aspects related to these concepts. To this end, we consider three types of points accumulating entropy and we investigate their existence, differences between them, and the possibility of disruptions.
Extraction of slow and fast dynamics of multiple time scale systems using wavelet techniques
Authors: A. Magrini Luciano , Oliveira Domingues Margarete , Macau Elbert E. N. , Kiss István Z.
Published: June 2020

A methodology is presented based on wavelet techniques to approximate fast and slow dynamics present in time-series whose behavior is characterized by different local scales in time. These approximations are useful to understand the global dynamics of the original full systems, especially in experimental situations where all information is contained in a one-dimensional time-series. Wavelet analysis is a natural approach to handle these approximations because each dynamical behavior manifests its specific subset in frequency domain, for example, with two time scales, the slow and fast dynamics, present in low and high frequencies, respectively. The proposed procedure is illustrated by the analysis of a complex experimental time-series of iron electrodissolution where the slow chaotic dynamics is interrupted by fast irregular spiking. The method can be used to first filter the time-series data and then separate the fast and slow dynamics even when clear maxima and/or minima in the corresponding global wavelet spectrum are missing. The results could find applications in the analysis of synchronization of complex systems through multi-scale analysis.
Tuning energy barriers by doping 2D group-IV monochalcogenides
Authors: Du Albert , Pendergrast Zachary , Barraza-Lopez Salvador
Published: June 2020

Structural degeneracies underpin the ferroic behavior of anisotropic next-generation two-dimensional materials and lead to peculiar two-dimensional structural transformations under external fields, charge doping, and/or temperature. The most direct indicator of the ease of these transformations is an elastic energy barrier, defined as the energy difference between the (degenerate) structural ground state unit cell and a unit cell with an increased structural symmetry. Proximity of a two-dimensional material to a bulk substrate can affect the magnitude of the critical fields and/or temperature at which these transformations occur, with the first effect being a relative charge transfer, which could trigger a structural quantum phase transition. With this physical picture in mind, we report the effect of modest charge doping (within −0.2 and +0.2 electrons per unit cell) on the elastic energy barrier Js of ferroelastic black phosphorene and nine ferroelectric/ferroelastic monochalcogenide monolayers. Js is the energy needed to create a Pnm21→P4/nmm two-dimensional structural transformation, and it is sensitive to the orbital character of the electronic charge added or removed. Similar to the effect on the elastic energy barrier of ferroelastic SnO monolayers, group-IV monochalcogenide monolayers show a tunable elastic energy barrier for similar amounts of doping, and a decrease (increase) of Js can be engineered under a modest hole (electron) doping of not more than one-tenth of an electron or a hole per atom.
Experimental and theoretical investigations of HeNeI2 trimer
Authors: Andreev Aleksei S. , Baturo Vera V. , Lukashov Sergey S. , Poretsky Sergey A. , Pravilov Anatoly M. , Zhironkin Anatoly I.
Published: June 2020

We report on the results of spectroscopic studies of the HeNeI2 van der Waals trimer using the two-step two-color HeNeI2(E0g+, vE = 0–3 ←hν2 B0u+, vB = 19 ←hν1 X0g+, vX = 0) excitation scheme. The excitation spectra of the HeNeI2(B, E) decay product luminescence and the luminescence spectra of I2 ion-pair states formed after HeNeI2(E) decay have been recorded and analyzed. The HeNeI2(X, B, E) binding energies have been estimated to be less than 111.8 cm−1, 101.6 cm−1, and 117.9 cm−1, respectively. The HeNeI2(B, vB) state decay has been found to be sequential with the formation of the HeI2(B, vB − 1) and NeI2(B, vB − 1) complexes without intermolecular excitation at the first step. An analysis of the HeNeI2(E) decay process based on the relative probabilities of the I2(D0u+) and I2(β1g) formation after decay, as well as vibrational populations of these states obtained from luminescence spectra, has also been performed. Calculations of the HeNeI2(X, B) vibrational energies using potential energy surfaces (PESs) of HeNeI2(X, B) constructed as a sum of the HeNe, HeI2, and NeI2 potentials have been carried out. The values obtained agree well with the experimental estimations, and the observed transitions can be ascribed to the HeNeI2 trimer of a tetrahedral geometry. Besides, a comparison of the PES constructed as a sum of the coupled-cluster single double triple [CCSD(T)] potentials with the PES based on the “direct” CCSD(T) calculations has been performed for the HeNeI2(X) trimer to verify the applicability of this representation to the trimer under study.
Simple tiles and attractors
Authors: Zaitseva T. I.
Published: June 2020

We study self-similar attractors in the space, that is, self- similar compact sets defined by several affine operators with the same linear part. The special case of attractors when the matrixof the linear part and the shifts of the affine operators are integer, is well known in the literature due to the many applications in the theory of wavelets and in approximation theory. In this case, if an attractor has measure one it is called a tile. We classify self-similar attractors and tiles in the case when they are either polyhedra or a union of finitely many polyhedra. We obtain a complete description of the matricesand the digit sets for parallelepiped tiles and for convex tiles in arbitrary dimensions. It is proved that on a two-dimensional plane, every polygonal tile (not necessarily convex) must be a parallelogram. Nontrivial examples of multidimensional tiles which are a finite union of polyhedra are given, and in the casea complete classification is provided for them. Applications to orthonormal Haar systems inand to integer univariate tiles are considered.

Bibliography: 18 titles.
On rigid germs of finite morphisms of smooth surfaces
Authors: Kulikov Vik. S.
Published: June 2020

In the article, we show that the germ of a finite morphism of smooth surfaces is rigid if and only if the germ of its branch curve has an

singularity type. We establish a correspondence between the set of rigid germs of finite morphisms and the set of Belyi rational functions

.

Bibliography: 10 titles.
Bounded automorphism groups of compact complex surfaces
Authors: Prokhorov Yu. G. , Shramov C. A.
Published: June 2020

We classify compact complex surfaces whose groups of bimeromorphic selfmaps have bounded finite subgroups. We also prove that the stabilizer of a point in the automorphism group of a compact complex surface of zero Kodaira dimension, as well as the stabilizer of a point in the automorphism group of an arbitrary compact Kähler manifold of nonnegative Kodaira dimension, always has bounded finite subgroups.

Bibliography: 23 titles.
A conformation-specific ON-switch for controlling CAR T cells with an orally available drug
Authors: Zajc Charlotte U. , Dobersberger Markus , Schaffner Irene , Mlynek Georg , Pühringer Dominic , Salzer Benjamin , Djinović-Carugo Kristina , Steinberger Peter , De Sousa Linhares Annika , Yang Nicole J. , Obinger Christian , Holter Wolfgang , Traxlmayr Michael W. , Lehner Manfred
Published: June 2020

Molecular ON-switches in which a chemical compound induces protein–protein interactions can allow cellular function to be controlled with small molecules. ON-switches based on clinically applicable compounds and human proteins would greatly facilitate their therapeutic use. Here, we developed an ON-switch system in which the human retinol binding protein 4 (hRBP4) of the lipocalin family interacts with engineered hRBP4 binders in a small molecule-dependent manner. Two different protein scaffolds were engineered to bind to hRBP4 when loaded with the orally available small molecule A1120. The crystal structure of an assembled ON-switch shows that the engineered binder specifically recognizes the conformational changes induced by A1120 in two loop regions of hRBP4. We demonstrate that this conformation-specific ON-switch is highly dependent on the presence of A1120, as demonstrated by an ∼500-fold increase in affinity upon addition of the small molecule drug. Furthermore, the ON-switch successfully regulated the activity of primary human CAR T cells in vitro. We anticipate that lipocalin-based ON-switches have the potential to be broadly applied for the safe pharmacological control of cellular therapeutics.
Phosphocholine accumulation and PHOSPHO1 depletion promote adipose tissue thermogenesis
Authors: Jiang Mengxi , Chavarria Tony E. , Yuan Bingbing , Lodish Harvey F. , Huang Nai-Jia
Published: June 2020

Phosphocholine phosphatase-1 (PHOSPHO1) is a phosphocholine phosphatase that catalyzes the hydrolysis of phosphocholine (PC) to choline. Here we demonstrate that the PHOSPHO1 transcript is highly enriched in mature brown adipose tissue (BAT) and is further induced by cold and isoproterenol treatments of BAT and primary brown adipocytes. In defining the functional relevance of PHOPSPHO1 in BAT thermogenesis and energy metabolism, we show that PHOSPHO1 knockout mice are cold-tolerant, with higher expression of thermogenic genes in BAT, and are protected from high-fat diet-induced obesity and development of insulin resistance. Treatment of mice with the PHOSPHO1 substrate phosphocholine is sufficient to induce cold tolerance, thermogenic gene expression, and allied metabolic benefits. Our results reveal a role of PHOSPHO1 as a negative regulator of BAT thermogenesis, and inhibition of PHOSPHO1 or enhancement of phosphocholine represent innovative approaches to manage the metabolic syndrome.
Mitochondrial protein interaction landscape of SS-31
Authors: Chavez Juan D. , Tang Xiaoting , Campbell Matthew D. , Reyes Gustavo , Kramer Philip A. , Stuppard Rudy , Keller Andrew , Zhang Huiliang , Rabinovitch Peter S. , Marcinek David J. , Bruce James E.
Published: June 2020

Mitochondrial dysfunction underlies the etiology of a broad spectrum of diseases including heart disease, cancer, neurodegenerative diseases, and the general aging process. Therapeutics that restore healthy mitochondrial function hold promise for treatment of these conditions. The synthetic tetrapeptide, elamipretide (SS-31), improves mitochondrial function, but mechanistic details of its pharmacological effects are unknown. Reportedly, SS-31 primarily interacts with the phospholipid cardiolipin in the inner mitochondrial membrane. Here we utilize chemical cross-linking with mass spectrometry to identify protein interactors of SS-31 in mitochondria. The SS-31-interacting proteins, all known cardiolipin binders, fall into two groups, those involved in ATP production through the oxidative phosphorylation pathway and those involved in 2-oxoglutarate metabolic processes. Residues cross-linked with SS-31 reveal binding regions that in many cases, are proximal to cardiolipin–protein interacting regions. These results offer a glimpse of the protein interaction landscape of SS-31 and provide mechanistic insight relevant to SS-31 mitochondrial therapy.
Pseudouridylation defect due to
DKC1
and
NOP10
mutations causes nephrotic syndrome with cataracts, hearing impairment, and enterocolitis
Authors: Balogh Eszter , Chandler Jennifer C. , Varga Máté , Tahoun Mona , Menyhárd Dóra K. , Schay Gusztáv , Goncalves Tomas , Hamar Renáta , Légrádi Regina , Szekeres Ákos , Gribouval Olivier , Kleta Robert , Stanescu Horia , Bockenhauer Detlef , Kerti Andrea , Williams Hywel , Kinsler Veronica , Di Wei-Li , Curtis David , Kolatsi-Joannou Maria , Hammid Hafsa , Szőcs Anna , Perczel Kristóf , Maka Erika , Toldi Gergely , Sava Florentina , Arrondel Christelle , Kardos Magdolna , Fintha Attila , Hossain Ahmed , D’Arco Felipe , Kaliakatsos Mario , Koeglmeier Jutta , Mifsud William , Moosajee Mariya , Faro Ana , Jávorszky Eszter , Rudas Gábor , Saied Marwa H. , Marzouk Salah , Kelen Kata , Götze Judit , Reusz George , Tulassay Tivadar , Dragon François , Mollet Géraldine , Motameny Susanne , Thiele Holger , Dorval Guillaume , Nürnberg Peter , Perczel András , Szabó Attila J. , Long David A. , Tomita Kazunori , Antignac Corinne , Waters Aoife M. , Tory Kálmán
Published: June 2020

RNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in
DKC1
,
NOP10
, or
NHP2
cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition. Here, we report a phenotype comprising nephrotic syndrome, cataracts, sensorineural deafness, enterocolitis, and early lethality in two pedigrees: males with
DKC1
p.Glu206Lys and two children with homozygous
NOP10
p.Thr16Met. Females with heterozygous
DKC1
p.Glu206Lys developed cataracts and sensorineural deafness, but nephrotic syndrome in only one case of skewed X-inactivation. We found telomere attrition in both pedigrees, but no mucocutaneous abnormalities suggestive of DC. Both mutations fall at the dyskerin–NOP10 binding interface in a region distinct from those implicated in DC, impair the dyskerin–NOP10 interaction, and disrupt the catalytic pseudouridylation site. Accordingly, we found reduced pseudouridine levels in the ribosomal RNA (rRNA) of the patients. Zebrafish
dkc1
mutants recapitulate the human phenotype and show reduced 18S pseudouridylation, ribosomal dysregulation, and a cell-cycle defect in the absence of telomere attrition. We therefore propose that this human disorder is the consequence of defective snoRNP pseudouridylation and ribosomal dysfunction.
Revealing the structure of a catalytic combustion active-site ensemble combining uniform nanocrystal catalysts and theory insights
Authors: Yang An-Chih , Choksi Tej , Streibel Verena , Aljama Hassan , Wrasman Cody J. , Roling Luke T. , Goodman Emmett D. , Thomas Dionne , Bare Simon R. , Sánchez-Carrera Roel S. , Schäfer Ansgar , Li Yuejin , Abild-Pedersen Frank , Cargnello Matteo
Published: June 2020

Significance

Catalysts are essential for a sustainable future because they reduce the energy required in chemical processes and the emission of harmful and polluting compounds. Revealing the function and structure of a working catalyst is a challenging task but critical in order to prepare more efficient and higher-performing materials. Very often, active sites are formed by many atoms that cooperate to perform the catalytic function. It is therefore challenging to identify the structure of the active site. Here, we combine uniform nanocrystal catalysts and theory insights to reveal the active-site ensemble necessary for alkene combustion. This approach can be extended to reveal atomistic details of working catalysts for a variety of applications.
DNA-based fluorescent probes of NOS2 activity in live brains
Authors: Veetil Aneesh T. , Zou Junyi , Henderson Katharine W. , Jani Maulik S. , Shaik Shabana M. , Sisodia Sangram S. , Hale Melina E. , Krishnan Yamuna
Published: June 2020

Significance

When a pathogen is engulfed by an immune cell, it is trapped in a transient organelle called the phagosome. The host cell recognizes the pathogen through receptors called Toll-like receptors (TLRs) that each recognize specific pathogen-associated molecular pattern (PAMP). When a TLR recognizes its cognate PAMP, it activates inducible nitric oxide synthase (NOS2), filling the phagosome with NO and destroying the pathogen. By developing a fluorescent reporter that directly images PAMP-triggered NOS2 activity in real time, we show that single-stranded RNA acts as a PAMP in zebrafish by activating its cognate TLR. Such a technology can help identify new PAMPs, pinpoint ligands for TLRs of unknown function, and suggest how PAMPs might synergize to help bugs evade the phagosomal deathtrap.
Indirectness and co-construction
Authors: Mey Jacob L.
Published: June 2020

Indirectness in language can basically be understood in two different ways: on the
one hand, there is the indirectness that is associated with the meaning (either literal or
‘indirect’) of the speaker’s words; on the other hand, we have the indirectness that
is specific for the discourse, understood as the textual work of co-constructing
meaning. The first kind of indirectness is a semantic-contextual one; the other kind
(while also relying on the context for its interpretation) is a pragmatic one, as it
involves the active collaboration of the interactants in language use. It is this
latter understanding of indirectness, in particular as it concerns the ‘voices’ of
the interactants and their access to the underlying ‘indirect’ meanings of the
discourse that will be the subject of my contribution.
Directness and indirectness in a presidential debate
Authors: Granato Luisa
Published: June 2020

This contribution examines the use of directness and indirectness as utilized by
the two candidates to the presidency of Argentina, in a debate broadcast on
television before the 2015 elections. Adopting a socio-pragmatic perspective, this
study makes a qualitative and quantitive analysis of addressivity at the micro and
meso levels of the interaction. An exploration of the form and function of the
interactants’ contributions demonstrated that directness is the preferred choice
when presentations and closing fragments are produced, while the questions and
answers addressed by the candidates to each other reveal differences in the use of
in/directness. These disparate strategies have a bearing on the interpersonal
discourse relationship between the two politicians and the audience.
The infalling photon, the infalling particle, and the observer at rest near the horizon of a black hole
Authors: Mazzitelli Francisco D
Published: June 2020

When a massive test particle or a photon fall radially into a black hole, their energy, as measured by a static observer located very close to the horizon, diverges. In introductory courses on general relativity, this fact gives rise to questions about the reality of this divergence and its eventual effect on the geometry of the black hole. We address these concerns and show that, eventually, it is the observer at rest who may induce corrections to the metric, unless its mass is crucially small when located near the horizon.
Effect of phonons on the electron spin resonance absorption
spectrum
Authors: Norambuena Ariel , Jimenez Alejandro , Becher Christoph , Maze Jerónimo R
Published: June 2020

The unavoidable presence of vibrations in solid-state devices can drastically
modify the expected electron spin resonance (ESR) absorption spectrum in
magnetically active systems. In this work, we model the effect of phonons and
temperature on the ESR signal in molecular systems with strong
E ⊗ e Jahn–Teller (JT)
effect and an electronic spin-1/2. Our microscopic model considers the linear JT
interaction with a continuum of phonon modes, the spin–orbit coupling,
the Zeeman effect, and the response of the system under a weak oscillating
magnetic field. We derive a Lindblad master equation for the orbital and spin
degrees of freedom, where one- and two-phonon processes are considered for the
phonon-induced relaxation, and the thermal dependence of Ham reduction factors
is calculated. We find that the suppression of ESR signals is due to phonon
broadening but not based on the common assumption of orbital quenching. Our
results can be applied to explain the experimentally observed absence of the ESR
signal in color centers in diamond, such as the neutral nitrogen-vacancy and
negatively charged silicon-vacancy color centers in diamond.
Laboratory Compaction Method of Soft Clay and Natural Plant Fiber/Shell Mixtures
Authors: Firmana Arifin Yulian , Misnawati  , Ridha Muhammad
Published: June 2020

One method of soil stabilization is to mix the soil with natural materials such as fibers or shells from plants. Generally, the samples are compacted in a laboratory by mean of Standard and Modified Proctor Compaction tests. The results of compaction are the relationship between water content and density, as indicated by the dry unit weight of the samples. In principle, this compaction process reduces the pore space filled with air in the soil. In this condition, soil is not saturated with water. The method cannot be used to compact soils that are in water-saturated conditions such as soft clay soils which are commonly found in wetland areas. This paper focuses on describing methods for compacting soft clay mixed with additional materials such as fibers and shells from plants. Two steps must be taken to compact samples of mixed soil and natural material. Firstly, determining the percentage of the mixture at which the sample can be compacted, and secondly, determining the optimum fiber/shell content to produce maximum density. The equipment and energy used are the same as the Proctor standard compaction test. Examples of calculations and results obtained for each material (i.e., empty fruit bunches and oil palm shells) are presented and discussed in the paper. Compaction procedures in the laboratory for the mixture of soft clay and other materials are also suggested in the paper.
Water management on peatland for food crop and horticulture production: research review in Kalimantan
Authors: Hairani A , Noor M
Published: June 2020

Water management is the most important component in developing peatlands for agriculture. Utilization of peatlands for food crops and research on its physical, chemical and biological characteristics have been carried out previously since a long time. However, the implementation of peatland management technology is not much well known. Peatland agricultural commodities are developing. In 1970-1990, mostly for food crops and horticulture. Since 2000 plantation crops had been developed rapidly. About 0.5-0.8 million ha of peatlands are planted by food crops, including horticulture and 2.5-3.0 million ha for oil palm. The use of peatlands is still being debated along with threats to the environment, especially greenhouse gas (CO2) emissions. The use of peatlands for agriculture by local communities aimed at sustaining life and has an interesting long history. Farmers who live in peatlands have special abilities and expertise in peatland management. Based on this experience and local wisdom, the government then planned to open peatlands, especially in supporting transmigration programs from Java, Nusa Tenggara, and Bali. However, the use of peatlands for agriculture has changed the fertility of peatlands and reported to be a trigger for land degradation so that improvement efforts are needed. The government has also issued several policies in improving the management and conservation of peatlands. This paper is a review of the results of research and experience on water management on peatlands for food crop and horticulture production.
Assessment and determination of potential sustainable biomass waste using the analytic network process method
Authors: Heryani H , Yanti N R
Published: June 2020

A global problem which has not been yet resolved is the volume of waste as a side effect of various activities whose numbers continue to increase. At present waste management becomes a challenge which is being faced by developing countries therefore starting from the selection of raw materials has been carried out an optimal sorting process for efficiency. This study aimed to assess and compare potential biomass waste as an alternative to sustainable waste efficiency. The study used the Analytic Network Process (ANP) method by making pairwise comparisons inter-criteria and inter-alternatives in assessing to obtain the weight of each criterion and alternative. The results showed a pairwise comparison value of cluster goal of potential sustainable biomass waste with the cluster availability of waste sources criteria having the highest priority weighting of 0.43017, compared to other clusters criteria. In the cluster alternatives, three biomass wastes with the highest priority weight were orange peel of 0.27376, pineapple leaf of 0.17764, and sugar palm peel of 0.15488, which were potential as sustainable biomass waste to be developed into various products biomass based such as for renewable heterogeneous catalysts, innovative craft products and various other high value-added products.
Effusion Cooling In Gas Turbine Combustion Chambers - A Comprehensive Review
Authors: Yellu Kumar K R , Qayoum Adnan , Saleem Shahid , Qayoum Faisal
Published: June 2020

Effusion cooling technique is an advanced concept for reducing the wall temperature in combustion chamber liners and gas turbine blades by injecting cross flow secondary fluid (coolant) through an array of holes having small diameter at close spacing. From last two decades, extensive works have been done for improving the life of hot components of gas turbines by different cooling methods. This paper discusses the review of the literature related to the geometrical parameter effects and factors affecting the adiabatic effectiveness of effusion cooling.
Design Optimization and Analysis of Car Bumper with the Implementation of Hybrid Biocomposite Material
Authors: Jain Vipul , Mittal Mohit , Chaudhary Rajiv
Published: June 2020

The components of an automobile are usually made up of steel and its alloy which leads to an increase in consumption of fuel. Moreover, a large amount of non-recyclable waste is being produced by the automotive sector. Therefore, it becomes necessary to move towards the lightweight, environment-friendly, and sustainable material which can replace the existing ones. In this regard, the current research work is focused on the pineapple leaf and glass fiber reinforced hybrid epoxy composite to be used for automotive car bumper. The bumper of Ambassador Car was designed in CATIA V5R18 and analyzed in ANSYS18.1. It was found that the geometrical optimization is an important parameter in structural strength improvement. The strength of automotive bumper was increased significantly after providing the strengthening ribs, changing the cross-section, and increasing the thickness. For static and impact analysis, the biocomposite bumper exhibits a lower value of deformation and higher value of strength than the steel and aluminium ones. The results of analysis and reduction in the mass of bumper have proved that the hybrid biocomposite material has significant potential for automotive structural components.
Design, development and analysis of a magnetorheological damper
Authors: Khuntia Satvik , Yadav Rithik , Singh R C , Rastogi Vikas
Published: June 2020

Magnetorheological Dampers or MR Dampers are advanced shock absorbers known for their fast response rate, wide dynamic range, mechanical simplicity and low power requirement. MR dampers use smart fluids called MR Fluids which can change dynamic yield stress when acted upon by a magnetic field. The damping force is changed by varying the rheological properties of the fluid magnetically. MR dampers are usually used in high-end automobiles. In this paper, an attempt has been made to make an alternative damper to the existing high-priced MR dampers which can be used in the mid-segment vehicles of today. A new design is proposed by the authors which incorporate the flow of the MR fluid through a hollow passage and focuses on making use of the strong magnetic field created at its center. Silicone oil as a carrier fluid, Carbonyl Iron power and White lithium grease as an additive are selected after studying fluid components. Before fabrication of the new design, numerical calculations are made to evaluate the strength of the magnetic field that is needed to provide suitable yield stress. A permeability around 3000 NA−2 is expected. This is estimated from the B-H curve for a commercial MR fluid called MRF - 32D. It is noted that a 43 SWG is the most suitable for the damper and with 4 - 5 windings, a maximum induced field of 1.2T (theoretically) can be produced at the center of the primary fluid column. This fluid column exists to a length of 80 mm while the coiling spanned up to 65 mm of the column. It is also concluded that these design parameters will be sufficient to create a strong magnetic field which can exert enough yield stress to give the desired results needed for damping.
Effect of elastic deformation on partial arc bearing with couple stress lubrication
Authors: Lambha Sanjeev Kumar , Kumar Vinod , Verma Rajiv
Published: June 2020

A combined effect of deformation in bush liner and non-Newtonian (couple stress(CSF)) fluid is studied here for the system of partial arc journal bearing. A Reynolds equation with modifications along with elasticity equation, solved to satisfy the conditions of boundary. The effect of using CSF with bearing deformation on load carrying capacity, maximum pressure, static and dynamic characteristics is observed. An iterative procedure is adopted to solve system of equations by using FEM approach.
Structural and magnetic analysis of electro-magnetic suspension spring
Authors: Saxena V , Pali H S
Published: June 2020

Suspension is the term given to the arrangement of springs, shock absorbers and linkages that interfaces a vehicle to its wheels. Unlike conventional suspension systems that smother the vibrations by scattering the vibration energy into waste heat, the regenerative suspension with vitality reaping shock absorbers can change over the generally squandered vitality into electricity. Thus in this work, designing of the suspension spring for Hero Splendor Plus bike by applying Nimonic 80A material. Specifically, it focuses on a static and dynamic study of the suspension spring. This framework uses electromagnets as inactive dampers, which is utilized to lessen displacement and acceleration of spring mass so as to enhance drive ease.
Tribological studies and Microstructural characterisation of SiC and Fly Ash Particles Based Aluminium 2024 alloy Composites Prepared through Stir Casting Route
Authors: Kumar Ashish , Singh R.C. , Chaudhary Rajiv , Singh Virendra Pratap
Published: June 2020

Aluminium and its alloys have excellent characteristics such as low density, high ductility and appropriate strength. In the marine, automotive and high-speed train sector, they find extensive applications. The volume percentage of metal matrix and reinforcement material and also the method of manufacturing the composites are the vital factors in making composite product. Composites of a metal matrix (MMCs), such as SiC and Al strengthened fly ash particles, are most widely used because of their excellent high hardness, high strength, corrosion resistance, stiffness and wear properties. The high strength and rigidity of AA 2024 alloys are well known. The high specific strength of such alloys with suitable reinforcement gives better yield properties and finds various applications at a reasonable cost. This article includes the study on mechanical and microstructural behaviour of AA 2024 metal matrix composites by reinforcing SiC and fly ash particles.
Study on the Behaviour of Green Concrete by the use of Industrial waste Material: A Review
Authors: Shukla Ashish , Gupta Nakul , gupta Ankur , Goel Rajesh , Kumar Sanjeev
Published: June 2020

Concrete nowadays is a material of all time and also the common used substance in which primary element is the cement. That is lime on the basis of establish materials utilized throughout with aggregate to form concrete. Require of cement for creation purpose to build concrete had lead to the gain CO2 discharge that view suspicion on worldwide nature. This day’s time the cost of achievement is mostly as well as the cost of substance. To build the concrete inexpensive and immature various attempt were construct on renewal of waste with cement, fine aggregate and course aggregate. Numerous find out the flexural strength, split tensile strength and compressive strength of concrete is on the basis of renewal with unfinished. That research analysis on the reaction of moderate the reduce waste materials like slag of blast furnace, dust of silica and dust of marble with Cement.
Maturity Model for IT Managed Services
Authors: Wattal Suneel
Published: June 2020

There is a growing trend for Enterprises to engage Managed Service Providers in order to outsource their IT related activities. The delivery capability of an MSP needs to be assessed in a standardized manner, which can be achieved by way of conceiving a Maturity model for the purpose. A study was conducted to develop a Maturity model for Managed Service providers. This model was implemented on a specific environment and the results were documented. The model had to undergo a few iterations and was refined during the implementation.
Controlling Over Enhancement of Images Using Histogram Equalization Technique
Authors: Raheja Anisha , Chawla Rashmi , Gupta Shailender , Vashist Akshar
Published: June 2020

Contrast Enhancement is a powerful technique to procure high quality images with outstanding contrast enrichment and an appreciable improvement in visual quality. A multitude of contrast enhancement schemes based on Histogram Equalization accomplished to improve image perceptibility are available in literature. Although these perform quite well, but image over enhancement is a stumbling block, which cannot be overlooked. This paper is an effort to resolve the above problem by incorporating a novel recursive approach, taking Histogram Equalization (HE) as the base methodology for improving the subjective quality of image. The proposed mechanism searches those portions of image where contrast enhancement is actually required, thus avoiding over enhancement. Furthermore, contrast adjustment is performed on the overall image so as to suppress the excessively enhanced regions. A simulator is designed in MATLAB 2016a to fulfil the defined purpose. The comparison results of proposed technique with already reported ones show that ours is better than others in terms of the performance metrics, Contrast Improvement Index(CII) and Colour Enhancement Factor (CEF).
Hazardous Wastes and its Impact on Human Health
Authors: Hasan M A , Mallick J , Ahmed M , Saleem M
Published: June 2020

Urban sprawl, population growth, rising living standards, and industrialization has resulted in waste generation in developing countries. Many solid waste sources contribute to hazardous waste which poses many pollution problems. The purpose of this study is to understand hazardous waste and its impact on human health and to address hazardous waste issues. The results revealed that hazardous waste, when incorrectly treated, processed and disposed of, has a significant impact on public health and the environment. Air pollution, water supply depletion and the spread of human diseases are the worst effects of insufficient waste management. It makes cities untidy and dirty, affects people’s health, harms flora and fauna, and hinders the economy of the countries. Some of the prevention such as hazardous waste handling, dilution, a tube-well structure using well-logging methods and other forms of geophysical monitoring designed specifically for the contaminated area, as well as the different treatment systems, could also be advised.
Tests of Electrical Motor for Installation in the Wheel Hub of an Electric Car
Authors: Bedkowski B , Dukalski P , Jarek T , Wolnik T
Published: June 2020

The article presents the construction of test stand for testing an electric permanent magnet synchronous motor (PMSM) with an external rotor. The results of laboratory tests such as temperature rise tests for various motor parameters (such tests allow to determine temperatures in important motor components during different driving conditions - calculated for Fiat Panda III) and load tests with the determination of efficiency maps in the entire range have been presented. It was assumed that the car’s drive is fitted with two motor in the rear axle.
Definition of Contact Stresses and Gaps in the Hinges of Chain Gears
Authors: Belousov Yu V , Shambina S L , Rekach F V
Published: June 2020

The article discusses the issues of determining contact stresses in the hinges of chain gears. It is necessary to know these stresses to assess the hinges’ wear resistance, since the wear of hinges (joints) is the most common cause of chain gears’ damage. In this regard, the focus was made on determining the necessary gap between the bushing and the roller of the chain gears. This gap significantly affects the largely determines the distribution pattern and magnitude of the stresses in the hinge, and, consequently, the wear resistance of chain gears. A method for calculating the maximum contact stress in the hinges of chain gears has been developed. It was proved that a decrease of the gap in the hinges influence in the following way: the contact angle between the roller and the bushing increases and the maximum contact stresses become lower. However, for real contact angles, the contact stresses greatly exceed the permissible average specific pressure, causing increased wear on the joints (hinges). One of the possible ways to solve this problem is to use transitional fittings in hinges, in which the gaps and tightness are relatively small. When pressing the rollers into the bushings, microroughnesses are cut from the contact surfaces, and the tightness in the connection practically disappears. Some examples of determining gaps and contact stresses in the hinges of chain gears are given.
Image potential states of germanene
Authors: Borca Bogdana , Castenmiller Carolien , Tsvetanova Martina , Sotthewes Kai , Rudenko Alexander N , Zandvliet Harold J W
Published: June 2020

We have measured the two-dimensional image potential states (IPS) of a germanene layer synthesized on a Ge2Pt crystal using scanning tunnelling microscopy and spectroscopy. The IPS spectrum of germanene exhibits several differences as compared to the IPS spectrum of pristine Ge(001). First, the n = 1 peak of the Rydberg series of the IPS spectrum of germanene has two contributions, labelled n = 1-
and n = 1+
, respectively. The peak at the lower energy side is weaker and is associated to the mirror-symmetric state with opposite parity. The appearance of this peak indicates that the interaction between the germanene layer and the substrate is very weak. Second, the work function of germanene is about 0.75 eV lower in energy than the work function of Ge(001). This large difference in work function of germanene and pristine Ge(001) is in agreement with first-principles calculations.
Atomic scale structure and its impact on the band gap energy for Cu2Zn(Sn,Ge)Se4 kesterite alloys
Authors: Ritter Konrad , Eckner Stefanie , Preiß Cora , Gurieva Galina , Bischoff Thomas , Welter Edmund , Botti Silvana , Schorr Susan , Schnohr Claudia S
Published: June 2020

Kesterite based materials gain more and more relevance in the pursuit of affordable, efficient and flexible absorber materials for thin film photovoltaics. Alloying Cu2ZnSnSe4 with Ge could allow controlled band gap engineering as already established for Cu(In,Ga)(S,Se)2 based solar cells. This study investigates the local atomic arrangements of Cu2Zn(Sn,Ge)Se4 alloys by means of low temperature Extended x-ray Absorbtion Fine Structure Spectroscopy. The element specific bond lengths are used together with x-ray diffraction data to derive the anion positions of the different local configurations. Ab initio theoretical calculations are performed to predict the influence of structural parameters such as anion position and lattice constants on the band gap energy. Combining the results of the experimental and theoretical studies suggests that the overall influence of the structural changes on the band gap bowing due to alloying is significant yet smaller than the total non-linear change of the band gap energy. Consequently, it is concluded, that band gap bowing stems from both structural and electronic changes.
The spectrum of the abelian sandpile model
Authors: Hough Robert , Son Hyojeong
Published: June 2020

In their previous work, the authors studied the abelian sandpile model on graphs constructed from a growing piece of a plane or space tiling, given periodic or open boundary conditions, and identified spectral parameters which govern the asymptotic spectral gap and asymptotic mixing time. This paper gives a general method of determining the spectral parameters either computationally or asymptotically, and determines the spectral parameters in specific examples.
Consistency of finite volume approximations to nonlinear hyperbolic balance laws
Authors: Ben-Artzi Matania , Li Jiequan
Published: June 2020

This paper addresses the three concepts of consistency, stability and convergence in the context of compact finite volume schemes for systems of nonlinear hyperbolic conservation laws. The treatment utilizes the framework of “balance laws”. Such laws express the relevant physical conservation laws in the presence of discontinuities. Finite volume approximations employ this viewpoint, and the present paper can be regarded as being in this category. It is first shown that under very mild conditions a weak solution is indeed a solution to the balance law. The schemes considered here allow the computation of several quantities per mesh cell (e.g., slopes) and the notion of consistency must be extended to this framework. Then a suitable convergence theorem is established, generalizing the classical convergence theorem of Lax and Wendroff. Finally, the limit functions are shown to be entropy solutions by using a notion of “Godunov compatibility”, which serves as a substitute to the entropy condition.
Roles for a lipid phosphatase in the activation of its opposing lipid kinase
Authors: Strunk Bethany S. , Steinfeld Noah , Lee Sora , Jin Natsuko , Muñoz-Rivera Cecilia , Meeks Garrison , Thomas Asha , Akemann Camille , Mapp Anna K. , MacGurn Jason A. , Weisman Lois S.
Published: June 2020

The phosphoinositide phosphatase Fig4 is predicted to turn over the signaling lipid PI3,5P2. It is shown that a major role of Fig4 is to elevate PI3,5P2 via dynamic regulation of the protein complex that activates its opposing lipid kinase, Fab1.
Measuring nucleus mechanics within a living multicellular organism: Physical decoupling and attenuated recovery rate are physiological protective mechanisms of the cell nucleus under high mechanical load
Authors: Zuela-Sopilniak Noam , Bar-Sela Daniel , Charar Chayki , Wintner Oren , Gruenbaum Yosef , Buxboim Amnon
Published: June 2020

A mechanical characterization of cell nuclei within living Caenorhabditis elegans nematodes reveals two protective mechanisms: (1) cytoskeletal decoupling of the nucleus at high load and (2) slow release rates of stored mechanical energy. Lamin knockdown softened the nucleus and attenuated deformation recovery, whereas aging increased nucleus stiffness.
Centrosomes are required for proper β-catenin processing and Wnt response
Authors: Vora Setu M. , Fassler Jan S. , Phillips Bryan T.
Published: June 2020

The Wnt/β-catenin pathway is a key cell signaling module utilized in cell fate specification. Recent studies suggest an interplay between Wnt/β-catenin signaling components and centrosome function. This study explores the net effects of centrosome loss on Wnt signaling and posttranslational β-catenin regulation.
Nonmuscle myosin 2 regulates cortical stability during sprouting angiogenesis
Authors: Ma Xuefei , Uchida Yutaka , Wei Tingyi , Liu Chengyu , Adams Ralf H. , Kubota Yoshiaki , Gutkind J. Silvio , Mukouyama Yoh-suke , Adelstein Robert S.
Published: June 2020

Efficient angiogenic sprouting depends on a dynamic cytoskeleton and focal adhesions. Here we show that nonmuscle myosin 2 functions to promote the retraction of cortical protrusions and the formation of focal adhesions during sprouting, thereby preventing excessive vascular branching.