bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beam modulation and bump-on-tail effects on Alfvén eigenmode stability in DIII-D
Authors: Van Zeeland M.A. , Bardoczi L. , Gonzalez-Martin J. , Heidbrink W.W. , Podesta M. , Austin M. , Collins C.S. , Du X.D. , Duarte V.N. , Garcia-Munoz M. , Munaretto S. , Thome K.E. , Todo Y. , Wang X. 
Published: March 2021

Abstract
Beam modulation effects on Alfvén eigenmode stability have been investigated in a recent DIII-D experiment and show that variations in neutral beam modulation period can have an impact on the beam driven Alfvén eigenmode spectrum and resultant fast ion transport despite similar time-averaged input power. The experiment was carried out during the current ramp phase of L-mode discharges heated with sub-Alfvénic 50–80 kV deuterium neutral beams that drive a variety of Alfvén eigenmodes unstable. The modulation period of two interleaved beams with different tangency radii was varied from shot to shot in order to modify the relative time dependent mix of the beam pitch angle distribution as well as the persistence of a bump-on-tail feature near the injection energy (a feature confirmed by imaging neutral particle analyzer measurements). As the beam modulation period is varied from 7 ms to 30 ms on/off (typical full energy slowing down time of τ
slow ≈ 50 ms at mid-radius), toroidicity-induced Alfvén eigenmodes (TAEs) located in the outer periphery of the plasma become intermittent and coincident with the more tangential beam. Core mode activity changes from reversed shear Alfvén eigenmodes (RSAEs) to a mix of RSAE and beta-induced Alfvén eigenmodes. Discharges with 30 ms on/off period do not have a persistent bump-on-tail feature, have the lowest average mode amplitude and least fast ion transport. Detailed analysis of an individual TAE using TRANSP kick modeling (Monte Carlo evolution of the distribution function with probabilistic ‘kicks’ by the AEs) and the resistive MHD code with kinetic fast ions, MEGA, find no strong role of energy gradient drive due to bump-on-tail features. Instead, the observed TAE modulation with interleaved beams is likely a pitch angle dependent result combined with slowing down of the tangential beam between pulses. For the conditions investigated, bump-on-tail contributions to TAE drive were found to be 5% or less of the total drive at any given time.
Identification heavy metal pollution in biological samples around cement plant in Aceh, Indonesia using Laser Induced Breakdown Spectroscopy ( LIBS)
Authors: Yuza N , Ajrina H , Lahna K , Ramli M , Suliyanti M M , Idris N 
Published: March 2021

Abstract
A study was conducted for identification of heavy metal pollution from biological sample as a potential proxy of environmental pollution due to industrial waste. The identification was conducted using the emerging analytical tool, namely laser induced breakdown spectroscopy (LIBS). The sample was collected from seawater near a cement plant in Aceh. Samples is a conch shell. The sample was dried in the open air and then prepared in the form of a pellet. The analysis was made by generating a plasma on the pellet sample using an Nd-YAG laser with a wavelength of 1,064 nm which is focused with a lens that has a focal length (f = 15 cm) by varying laser energy under low pressure of 3 Torr of air surrounding gas. Emission from the generated plasma was transmitted to the Maya2000 spectrometer optical detector using an optical fiber and then the emission spectrum of each element is displayed on the monitor. The results showed that the snail shell contained the salts and heavy metal elements K, Pb, Gd, Se, Mg, Rb, Fe, and Xe. Thus, it can be concluded that the heavy metal elements Pb and Fe can be detected LIBS technique from the biological sample.
Dynamic networking and channel access strategies of hybrid communication network for intelligent ship
Authors: Huang Xiaoyun , Liu Wen 
Published: March 2021

Abstract
Based on the architecture of the hybrid maritime communication system, the shipboard hybrid communication network structure is presented for multi-network and multi-mode transmission networking equipment of intelligent ship. The paper briefly introduces the proposed dynamic networking and channel access strategies for the communication system of ship-to-ship and ship-to-shore, as well as the communication data types and priorities, quantitative description for each data and performance of each link. Those strategies make the shipboard communication link will be established automatically and flexibly with many modern communication technologies which will be selected depending on the current conditions of the radio channel and the requirements and preferences of the user. Simulation experiments show that those strategies could achieve the flexible and efficient data transmission with high throughput and low delay, using the advantage of each communication technology.
CFD numerical simulations of inertia stopping of a very large gas carrier using overset grid technology and body-force propeller
Authors: Hao Hao , Weimin Chen , Zixin Wu 
Published: March 2021

Abstract
With the development of International shipping, waterways all over the world are becoming increasingly crowded. Research on inertia stopping ability of large ships is essential to voyage safety. At present, the inertial stopping of ship is mainly measured by ship model test, and there is little work to study the performance using CFD technology. STARCCM+based on the ship 6-DOF motion and overset grid technology and body-force method are used to numerically simulate the inertia stopping maneuver of a very large gas carrier. By controlling the rotation speed of the propeller, the ship is in a stable state of motion. Then set the speed to zero.The motion state and detailed flow field information of the ship model during motion can be got by solving viscous flow field. To verify the accuracy of numerical prediction results, ship model test is launched. Both the trajectory of the ship and the value of the characteristic parameter match very well.
Numerical study on the scale effect of high-skew propeller E1619
Authors: Liu L W , Chen M X , Wu Y H , Zhang Z G , Wang X Z 
Published: March 2021

Abstract
In this study, a large skewed propeller INSEAN E1619 model with 7 blades working in open water conditions has been numerically simulated by an inhouse URANS (Unsteady Reynolds-averaged Navier-Stokes) code coupled with dynamic overset grid approach. Grid and time-step sensitivity analysis of the propeller model has been conducted and the numerical results have been compared with available experimental data performed by INSEAN aimed to validate the numerical method. Propeller open water characteristics have been compared for models with different scales at given advance coefficient to evaluate scale effect of this high-skew propeller. Non-dimensional pressures on different scaled models have been compared between models with different scales. Results show that propeller’s thrust and torque increase with the increase of propeller scale, which is mainly due to the increase of pressure component. It could be found that the pressure on suction side near the trailing edge decreases with the increase of propeller’s scale.
Millimeterwave reflectivity tests on MetOp-SG MWI On Board Calibration Target
Authors: Simonetto A. , Cuttaia F. , Biggi M. , Lapini R. , Lupi T. , Mandolesi N. , Matticari G. , Morgante G. , Salaris P. , Salghetti Drioli L. , Terenzi L. 
Published: March 2021

Abstract
The On-Board Calibration Target (OBCT) for the Micro-Wave
Imager instrument on the MetOp-SG-B satellite is a microwave
blackbody, operating between 14 and 220 GHz (extended frequency
range), providing the MWI receivers with a warm calibration
reference. It is designed for an emissivity better than 0,9999 over
the MWI 26 channels (including dual polarization channels). The OBCT
radiometric performance has been extensively verified in ISTP
(formerly IFP) microwave laboratory, by measuring reflectivity over
the extended bandwidth. Measurement techniques and results are
described in this paper, showing that the OBCT models tested so far
are fully compliant with the MWI requirements.
Effect of aerosol-induced snow darkening on the direct radiative effect of aerosols over the Himalayan region
Authors: Usha K H , Nair Vijayakumar S , Babu S Suresh 
Published: March 2021

Abstract
Regional heterogeneity in direct and snow albedo forcing of aerosols over the Himalayan cryosphere was investigated using a regional climate model coupled with the community land model having snow, ice and aerosol radiation module. Deposition of absorbing aerosols like dust (natural) and black carbon (BC) (anthropogenic) decreases the snow albedo (snow darkening) over the Himalayas. Western Himalayas experiences a large reduction in the snow albedo (0.037) despite having lower BC mass concentration compared to central (0.014) and eastern (0.005) Himalayas. The contribution of BC and dust to the snow albedo reduction is comparable over the western and eastern Himalayas. The inclusion of aerosol-induced snow darkening in to the model reduces its bias with respect to the satellite derived surface albedo by 59%, 53% and 35% over western, central and eastern Himalayas respectively during the spring season. Since surface albedo decides the sign and magnitude of aerosol direct radiative forcing, aerosol induced snow darkening significantly affects the direct radiative effects of aerosols. Hence, the aerosol-induced decrease in snow albedo causes an early reversal in the sign of aerosol direct radiative forcing at the top of the atmosphere from warming to cooling over the western and central Himalayas, which can have implications in the radiation balance and water security over the region.
An exact solution to asymptotic Bethe equation
Authors: Miao Yuan 
Published: March 2021

Abstract
We present an exact solution to the asymptotic Bethe equation of weakly anisotropic Heisenberg spin chain, which is a set of non-linear algebraic equations. The solution describes the low-energy excitations above ferromagnetic ground state with fixed magnetisation, and it has a close relation to generalised Jacobi polynomial. It is equivalent to a generalised Stieltjes problem and in the continuous limit, it becomes a Riemann–Hilbert problem closely related to the finite-gap solutions of classical Landau–Lifshitz field theory.
The Bloch vectors formalism for a finite-dimensional quantum system
Authors: Loubenets Elena R , Kulakov Maxim S 
Published: March 2021

Abstract
In the present article, we consistently develop the main issues of the Bloch vectors formalism for an arbitrary finite-dimensional quantum system. In the frame of this formalism, qudit states and their evolution in time, qudit observables and their expectations, entanglement and nonlocality, etc are expressed in terms of the Bloch vectors—the vectors in the Euclidean space

R

d

2

−
1

, arising under decompositions of observables and states in different operator bases. Within this formalism, we specify for all d ⩾ 2 the set of Bloch vectors of traceless qudit observables and describe its properties; also, find for the sets of the Bloch vectors of qudit states, pure and mixed, the new compact expressions in terms of the operator norms that explicitly reveal the general properties of these sets and have the unified form for all d ⩾ 2. For the sets of the Bloch vectors of qudit states under the generalized Gell‐Mann representation, these general properties cannot be analytically extracted from the known equivalent specifications of these sets via the system of algebraic equations. We derive the general equations describing the time evolution of the Bloch vector of a qudit state if a qudit system is isolated and if it is open and find for both cases the main properties of the Bloch vector evolution in time. For a pure bipartite state of a dimension d
1 × d
2, we quantify its entanglement via the characteristics of the Bloch vectors for its reduced states. The introduced general formalism is important both for the theoretical analysis of quantum system properties and for quantum applications, in particular, for optimal quantum control, since, for systems where states are described by vectors in the Euclidean space, the methods of optimal control, analytical and numerical, are well developed.
Design and Fabrication of an Ablative Pyrolyzer for Production of Bio- lubricants and chemicals in Oil Well Drilling Application
Authors: Adegoke S.O. , Adeleke A.A. , Ikubanni P.P. , Falode A.O , Alawode A.J. , Agboola O.O. , Adediran A.A. 
Published: March 2021

Abstract
In this study, an ablative pyrolyser having 27.1 cm inner diameter, 41.2 cm outer diameter, the full chamber height of 74.7 cm and chamber volume of 40 litres was designed and fabricated. 150KW heater was wounded around the reactor chamber made of stainless steel to provide a higher temperature of up to 1400 °C. The -40 to 105°C capacity heat resistance wires were used to conduct the heater into the electrical panel which has several components such as the contactor, temperature controller, thermocouple wire and so on to give a particular desired working temperature. This pyrolyser applies technology of thermal energy in the heated walls of the pyrolyser being transferred to the biomass by conduction in the absence of oxygen for onward disintegration into gas, bio-oil, and biochar. After fabrication, 12 kg each of Tectona grandis and Rhopalosiphum maidis was fed into the reactor and pyrolyzed at 500 °C, the bio-oil product for both samples were mixed together and distilled at 120 °C and the bio-oil distillate was characterized for density, kinematic viscosity, pH, acid value and free fatty acid content. The bio-oil distillate shows a density of 0.960 g/cc, pH of 7.2, kinematic viscosity of 84 cst and acid value of 42.20 compared to the bio oil crude which showed higher values. This pyrolyser has been found on average to melt 12 kg each of Tectona grandis and Rhopalosiphum maidis to 5353 and 3493 g crude bio-oil respectively for a period of at least 3 h. The mass of bio-char for tectona grandis and Rhopalosiphum maidis were 3325 and 2614 g respectively while the reactor requires 8 h to cool before discharging the bio-char from the reactor. This research work can provide a basic designing formula for effective and workable ablative pyrolyzer fabrication for Nigerian wastes having high energy content.
Socio-Cultural Resilience to Domestic Space Change, the Benin Traditional City Experience, Nigeria
Authors: Ekhaese E N , Evbuoma I K , George T O 
Published: March 2021

Abstract
Research over time has revealed that activity spaces in domestic home have undergone evolution, adaptation and resilience over the years across Benin residential zones, Nigeria. Space segments/activities sections like cooking/eating, household goods storage, visitors and conveniences sections have somehow remain unchanged in terms of function, meaning, and arrangement. The study identified socio-cultural factors as responsible for resilience of domestic space to change in Benin domestic architecture across Benin City. The paper engaged both qualitative and quantitative research method. Triangulation was adopted for collection through focused group discussion using Semi-structured interview guide, questionnaire, observation guide and photographs. Factor analysis was use to analysis of data in order to reduce the identified socio-cultural factors to sizeable portion. The finding showed that, whilst some activity space, it size and location have evolved in Benin contemporary architecture, the style has remained intact. For instance some activity spaces in some residential zone of the city have been adapted to suit the new realities. Further observation itemised the socio-cultural factors that are responsible for resilient to change in Benin domestic architecture. Result of research underscores the role of culture in process of architectural development amidst rapid urbanization. Research upon completion is expected to be a good case study for measuring resilience to evolution of spaces in typical house setting in any African traditional city.
The role of solvent additive in metal nano-composite doped thin film organic solar cell
Authors: Kesinro R. O. , Boyo A. O , Akinyemi M. L. , Hamed M.S.G. , Kaviyarasu K. , Mola G. T. , Emetere M. E. , Aizebeokhai A. P. 
Published: March 2021

AbstractIn this study, organic solar cells (OSCs) were designed using the solution processing method based on spin coating. The influence of solvent additive (1-chloronapthalene (CN)) and cadmium doped barium nitrate nanoparticle incorporated into the photoactive medium based on poly(3-hexylthiophene-2,5-diyl (P3HT): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was investigated. The power conversion efficiency of the pristine device was compared to the power conversion efficiency of the devices fabricated with 30v% of 1- chloronapthalene and different weight concentrations of nanoparticles. An optimum efficiency of 3.55 % was attained at 0.3 wt.% with solvent additive compared to 3.25 % obtained for the pristine device. This increase is attributed to a rise in charge transport of 5.32 × 10−2cm2V−1s−1. Further investigation on the morphological properties of the nanoparticles reveals the crystalline nature of the nanoparticle.
Role of Biomaterials in Automation.
Authors: Fayomi O. S. I. , Adedeji A.A. , Agboola O. , Ajala M.O , Bolu C.A , Banjo S.O. , Udoye N. E. 
Published: March 2021

Abstract
Technology in its real sense is in an advanced state to an extent that automation is the present-day mode of operating machinery and equipment. This technique of operating or controlling a process using a highly automatic means via electronic devices thereby reducing the human interface to a minimum, if not rather than eliminating it completely. Transformation of the global workforce has already begun through automation with innovations of robotics, artificial intelligence remote connectivity, additive manufacturing and medical innovations employing the automated means of delivering or administering drugs and performing surgery on patients. In the present day, various forms of automation are increasingly taking over the place of human thereby, putting a threat to supplant it. The role of biomaterials in automation is the main objective in this discuss.
The study revealed that metals play a major role in biomaterials due to its excellent thermal conductivity and mechanical properties.
The nexus of climate change, urban infrastructure and sustainable development in developing countries
Authors: Oloke O.C. , Fayomi O.S.I. , Oluwatayo A. , Adagunodo T.A. , Akinwumi I.I. , Amusan L.M. 
Published: March 2021

Abstract
This study weighed in on the topical issue of climate change impacts and sustainable urban development in developing countries. Climate change is a global challenge that is much discussed at national and international fora. The study reflects on the lot and plight of cities and peri-urban communities in developing countries in the face of lopsided attention on climate change. Extant studies, articles, local and international reports on climate change, urbanization and infrastructure, extant literatures were reviewed to establish the perspective and position of the study. The study examined the global threats of climate change and the local impact of disasters to urban dwellers in developing countries like Nigeria. It further shed light on urbanization process and the state of infrastructure in developing countries. Vulnerability of cities in the areas of infrastructure was brought to the fore with a view to improving the capacity and preparedness against climate change impact. Concepts of climate change, urbanization challenge, urban infrastructure, sustainable development were reviewed to contextualize the study. The study concluded by advocating for positive urbanization to mitigate the effect of climate change and foster sustainable development agenda in developing countries.
Tropospheric attenuation on Satellite-aircraft propagation: A concise review
Authors: Arijaje T. E , Omotosho T. V , Aizebeokhai A. P , Akinwumi S. O 
Published: March 2021

Abstract
The attenuation time together with the Complementary Cumulative Distribution Function of attenuation values play a vital role in the design of communication systems. Passengers on-board during flight can be connected to the internet either via satellite or earth-station depending on the nature of the flight. For long distance flight, this internet connectivity is provided through satellite when the aircraft is flying at the upper troposphere. However, the satellite-aircraft link is subject to attenuation due to the troposphere. A model to characterize the channel has been proposed. In particular, a methodology for the synthesis of attenuation on aircraft-satellite is given by ITU-R P2041 recommendation. However, it has been shown that the impact of tropospheric parameters such as rainfall, cloud, gases etc. On the satellite-aircraft link at different frequencies are insignificant (i.e decreases with height) on the upper troposphere since the aircraft is flying (about 12 km) above the rain height (5 km). The findings will be useful for researchers, scientists and the aviation industries in planning, design and establishing link budget for aircraft-satellite path.
Maintenance Culture Of Residents In Some Selected Low Cost Housing Estate In Lagos State
Authors: Lekan Amusan , Oluwaseun Oluwabusuyi , Judith Ezenduka , Moses E. Emetere , Dashe Chalya 
Published: March 2021

Abstract
Building infrastructures is part of what provides people with shelter, protection and comfort in a country. It is one of the major factors for survival and wellbeing of people. It is therefore very important that the facilities of buildings be constantly preserved and maintained well to meet up with occupants satisfaction therefore meeting the purpose for which they were built and developed. for. The sample size is the total number of observations, population elements of sampling unit that are selected for investigation in the study. The sample size of this study was developed from 3 selected low cost housing estate within Lagos and a relatively 75 questionnaires was distributed to various residents for evaluation of maintenance practice. The following facts were discovered in the study that low grade materials are mostly used in construction of low cost building which leads to major deterioration in component of the building, poor contribution of professionals and stakeholders in the construction industry to training programs and strategies from the factors for the good maintenance practices were insignificant among others. The study further recommend the following facts: Training and retraining of artisans and craftsmen should be embraced an essential strategy, construction firms should invest in the training and retraining of their craftsmen to promote optimum performance while construction professionals and stakeholders should contribute to the skills acquisition programmes both onsite and offsite
Response surface methodology for silicon production from bamboo leaves
Authors: Olawale O , Akinyemi B , Ogundipe S.J , Abayomi S.T , Adekunle A.A. 
Published: March 2021

Abstract
This study investigated the production of silicon from bamboo leaves to solve the challenge of silicon in solar market using Optimization approach. The effect of three independent variables of: temperature, time and amount of bamboo leaves were studied using Box Behnken design. The best process level observed from the Box Benhken Design and optimal predicted process were used to produce silica. It was then subjected to X-Ray Diffractometer to determine the most reactive silica. The most reactive silica observed was used to produce silicon. Silicon obtained was subjected to X-Ray Diffraction and Scanning Electron microscope. It was concluded that nanosilicon was produced which can be used as a solar cell component to solve the challenge presently in the solar market.