bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homogeneous-isotropic sector of loop quantum gravity: new approach
Authors: Kisielowski Marcin 
Published: June 2020

Abstract
Recently, a new class of scalar constraint operators has been introduced in loop quantum gravity. They are defined on a space of solutions to the Gauss constraint and partial solutions to the vector constraint, called a vertex Hilbert space. We propose a subspace of the vertex Hilbert space formed by homogeneous-isotropic states, which is invariant under the action of the new scalar constraint operators. As a result, the operators can be reduced to our homogeneous-isotropic subspace. The (generalized) eigenstates of the reduced operator are eigenstates of the full operator. We discuss the feasibility of numerical diagonalization of the reduced scalar constraint operator.
Simulation of capillary-driven kinetics with multi-phase-field and lattice Boltzmann method
Authors: Schiedung Raphael , Tegeler Marvin , Medvedev Dmitry , Varnik Fathollah 
Published: June 2020

Abstract
We propose a combined computational approach based on the multi-phase-field and the lattice Boltzmann method for the motion of solid particles under the action of capillary forces. The accuracy of the method is analyzed by comparison with the analytic solutions for the motion of two parallel plates of finite extension connected by a capillary bridge. The method is then used to investigate the dynamics of multiple spherical solid bodies connected via capillary bridges. The amount of liquid connecting the spheres is varied, and the influence of the resulting liquid-morphology on their dynamics is investigated. It is shown that the method is suitable for a study of liquid-phase sintering which includes both phase transformation and capillary driven rigid body motion.
High-brightness broad-area diode lasers with enhanced self-aligned lateral structure
Authors: Elattar M , Brox O , Della Casa P , Maaßdorf A , Martin D , Wenzel H , Knigge A , Crump P 
Published: June 2020

Abstract
Broad-area diode lasers with increased brightness and efficiency are presented, which are fabricated using an enhanced self-aligned lateral structure by means of a two-step epitaxial growth process with an intermediate etching step. In this structure, current-blocking layers in the device edges ensure current confinement under the central stripe, which can limit the detrimental effects of current spreading and lateral carrier accumulation on beam quality. It also minimizes losses at stripe edges, thus lowering the lasing threshold and increasing conversion efficiency, while maintaining high polarization purity. In the first realization of this structure, the current block is integrated within an extreme-triple-asymmetric epitaxial design with a thin p-doped side, meaning that the distance between the current block and the active zone can be minimized without added process complexity. Using this configuration, enhanced self-aligned structure devices with 90 µm stripe width and 4 mm resonator length show up to 20% lower threshold current, 21% narrower beam waist, and slightly higher (1.03×) peak efficiency in comparison to reference devices with the same dimensions, while slope, divergence angle and polarization purity remain almost unchanged. These results correspond to an increase in brightness by up to 25%, and measurement results of devices with varying stripe widths follow the same trend.
Coherent, high repetition rate tender x-ray free-electron laser seeded by an extreme ultra-violet free-electron laser oscillator
Authors: Petrillo V , Opromolla M , Bacci A , Broggi F , Drebot I , Ghiringhelli G , Puppin E , Rossetti Conti M , Rossi A R , Ruijter M , Samsam S , Tagliaferri A , Rossi G , Serafini L 
Published: June 2020

Abstract
A seeded FEL driven by a linac based on super conducting cavities, generating 108–1010 coherent photons per shot at 2–5 keV with 0.2–1 MHz of repetition rate, can address the need of a source devoted to fine analysis of matter using the linear spectroscopy technique. The seeding scheme described hereafter is a multi-stage cascade upshifting the radiation frequency by a factor 20–40. The x-ray range can be achieved with a seed constituted by a coherent flash in the extreme ultraviolet range provided by an FEL oscillator operating at 12–14 nm. The whole chain of x-ray generation is described by means of start-to-end three-dimensional simulations.
Precise high-fidelity electron–nuclear spin entangling gates in NV centers via hybrid dynamical decoupling sequences
Authors: Dong Wenzheng , Calderon-Vargas F A , Economou Sophia E 
Published: June 2020

Abstract
Color centers in solids, such as the nitrogen-vacancy center in diamond, offer well-protected and well-controlled localized electron spins that can be employed in various quantum technologies. Moreover, the long coherence time of the surrounding spinful nuclei can enable a robust quantum register controlled through the color center. We design pulse sequence protocols that drive the electron spin to generate robust entangling gates with these nuclear memory qubits. We find that compared to using Carr-Purcell-Meiboom-Gill (CPMG) alone, Uhrig decoupling sequence and hybrid protocols composed of CPMG and Uhrig sequences improve these entangling gates in terms of fidelity, spin control range, and spin selectivity. We provide analytical expressions for the sequence protocols and also show numerically the efficacy of our method on nitrogen-vacancy centers in diamond. Our results are broadly applicable to color centers weakly coupled to a small number of nuclear spin qubits.
Hierarchy of coherent structures in turbulent channel flow
Authors: Motoori Yutaro , Goto Susumu 
Published: June 2020

Abstract
By analyzing a database of fully developed turbulent channel flow at the friction Reynolds number Reτ
= 4179, we investigate the sustaining mechanism of a hierarchy of coherent structures in the wall-bounded turbulence. For this purpose, we decompose the turbulent fields into different scales by a band-pass filter. Using the filtered velocity and velocity gradients, we identify the hierarchy of coherent structures to observe that the largest-scale structures at each distance from the wall are composed of quasi-streamwise vortices and low-speed streaks. Since these are similar to well-known coherent structures in the buffer layer, they are likely to be maintained by the self-sustaining process. In contrast, structures smaller than the distance from the wall distribute isotropically. These observations are also confirmed by using a conditional sampling method. Moreover, quantifying the scale-dependent contributions to the vortex stretching and energy transfer, we show that the largest-scale coherent structures are strongly affected by the mean shear, whereas smaller-scale vortices are generated by the energy cascading events. Incidentally, in large-scale ejection regions (i.e. large-scale low-speed streaks), the cascading events are stronger than in large-scale sweep regions.
Selective opposition-like control of large-scale structures in wall-bounded turbulence
Authors: Ibrahim J I , Guseva A , Garcia-Mayoral R 
Published: June 2020

Abstract
We investigate the effect of controlling large-scale, logarithmic-layer turbulent structures, which have a characteristic size and aspect ratio that scale with the distance from the wall. The aim is to quantify the effect of suppressing these structures while leaving the near-wall turbulent dynamics unaltered. By affecting only the logarithmic-layer structures, it might be possible to isolate their contribution to the drag from that of the other scales in the flow. We conduct direct numerical simulations of turbulent channel flows at friction Reynolds number ReT
?s 500-1000 and artificially remove certain streamwise and spanwise wavelengths of the wall-normal velocity across a range of heights. The wavelengths chosen depend on the target height (and size) of the structures that we wish to target. When these wavelengths are removed, we observe a positive, outward shift of the mean velocity profile above the target height, due to a local reduction in Reynolds shear stress, and a subsequent increase in viscous stress. Our preliminary results suggest that this shift in the mean velocity profile scales in outer units.
Active flow control for external aerodynamics: from micro air vehicles to a full aircraft in stall
Authors: Lehmkuhl Oriol , Lozano-Durán Adrián , Rodriguez Ivette 
Published: June 2020

Abstract
We investigate the aerodynamic performance of active flow control of airfoils and wings using synthetic jets with zero net-mass flow. The study is conducted via wall-resolved and wall-modeled large-eddy simulation using two independent CFD solvers: Alya, a finite-element-based solver; and charLES, a finite-volume-based solver. Our approach is first validated in a NACA4412, for which numerical and experimental results are already available in the literature. The performance of synthetic jets is evaluated for two flow configurations: a SD7003 airfoil at moderate Reynolds number with laminar separation bubble, which is representative of Micro Air Vehicles, and the high-lift configuration of the JAXA Standard Model at realistic Reynolds numbers for landing. In both cases, our predictions indicate that, at high angles of attack, the control successfully eliminates the laminar/turbulent recirculations located downstream the actuator, which increases the aerodynamic performance. Our efforts illustrate the technology-readiness of large-eddy simulation in the design of control strategies for real-world external aerodynamic applications.
Progress in climate change adaptation in the Arctic
Authors: Canosa I V , Ford J D , McDowell G , Jones J , Pearce T 
Published: June 2020

Abstract
Climate adaptation is a priority for Arctic regions which are witnessing some of the most rapid warming globally. Studies have documented examples of adaptation responses in the Arctic, but assessments evaluating if and how progress is being made over time remain scarce. We identify and examine adaptation progress in the Arctic using a systematic tracking methodology to compare adaptations documented during 2014–19 to those documented for the period 2004–2013 in a benchmark study by Ford et al (2014). Utilising the peer reviewed literature as out data source, we find no noticeable increase in reported adaptations across the two time periods, with the profile of adaptations undertaken remaining largely the same. The majority of documented adaptations continue to be reported in North America, are being undertaken most often in the subsistence-based hunting and fishing sector, are primarily developed in response to a combination of climatic and non-climatic stimuli, are reactive and behavioural in nature, and are mainly carried out at the individual/community scale. Climate change is observed, however, to have a more prominent role in motivating adaptation between 2014–19, consistent with intensifying climate-related exposures in the Arctic. There is limited evidence in the reported adaptations analysed that potential opportunities and benefits from the impacts of climate change are being targeted. The paper provides a general characterisation of adaptation across the Arctic and how it is evolving, and needs to be complimented in follow-up work by studies using alternative data sources on adaptation and research at national to regional scales.
Numerical coalescence of chaotic trajectories
Authors: Roth Bruce N , Wilkinson Michael 
Published: June 2020

Abstract
Pairs of numerically computed trajectories of a chaotic system may coalesce because of finite arithmetic precision. We analyse an example of this phenomenon, showing that it occurs surprisingly frequently. We argue that our model belongs to a universality class of chaotic systems where this numerical coincidence effect can be described by mapping it to a first-passage process. Our results are applicable to aggregation of small particles in random flows, as well as to numerical investigation of chaotic systems.
Cost control mechanism as procurement selection decision matrix for Malaysian infrastructure projects
Authors: Romeli N , Muhamad Halil F , Ismail F , Hasim M S 
Published: June 2020

Abstract
Malaysia was enumerated as the realm that retains a high quality of infrastructure facilities among the other ASEAN countries, and the number of infrastructure projects is progressively developed to offers a virtuous cordiality to the citizen. Inevitably, the infrastructure projects are barely devoted to the complex project selection decision phase where the procurement represents the suave configuration of the projects. However due to the difficulty in analyzing an assorted variety of procurement system afford by inexperienced decision maker the procurement route often unkempt the cost related dynamic. Regularly, the decision based on narrow consideration of cost and project quality overestimated in within a short period of construction. Even worst, there is partially public discourse on the cost control elements towards the disputable project procurement selection, which reflects the lesson learnt on the previous infrastructure project has mismanaged to provide a municipal cost precaution. Prior to that, the research objective is to identify the relationship in between the cost control mechanism and project procurement selection decision in infrastructure projects. The adoption of quantitative method and analysis applies in this research among the infrastructure expert settings. The output from the methods disclose that the cost control acquires a strong correlation in the project procurement selection decision equation with project risk, capital resources, alliance requirement based, changes of policy, fluctuation of inflation rates, labor cost, material cost, robust feasibility studies as a driver to an efficacious project procurement assortment verdict.
Vulnerability assessment of building material against river flood water: case study in Malaysia
Authors: Balasbaneh A T , Abidin A R Z , Ramli M Z , Khaleghi S J , Marsono A K 
Published: June 2020

Abstract
Flood risk is increasing in Malaysia specifically around river which influencing of climate change. The aim of this study is assessing the vulnerability of building materials by revealing the degree of loss for each structure. There are most five common materials has been assessing namely: brick, concrete block, steel wall panels, wooden wall and precast concrete framing. This research was conducted on 110 buildings, to record detailed attributes of each building in the city of Kuantan. Afterwards, the interviews were conducted with residents of 85 households along with a local authority staff expert. The lowest flood depth that effected on wall building was 25 cm and the highest depth of flood was recorded 150 cm. In general, the interview revealed that the flood lasted for 48 hours. The vulnerability of the structural type of building is determined from the percentages of damage to the wall material resulting from occurrence of the flood. Vulnerability curves were made for these five structural types, by plotting the relationships between flood depth and damage for each structural type. The result shows that by increasing the flood depth wood wall encounter by more damage, which needs more cost to repair. In other hand, Concrete block wall, which consider as one of the industrial building systems has less damage against floodwater. Although, until the depth of 75 cm both Concrete block wall and precast concrete has a same stability. The result of this research can help housemaker to choose the best material for building in flood zone area, which needs less cost in repair stage after flood hit the building.
Awareness of Building Information Modeling Implementation in Retrofitting the Existing Residential Building in Malaysia
Authors: Kermanshahi Emad Kasra , Tahir Mahmood Bin Md , Shukor Lim Nor Hasanah Abdul , Balasbaneh Ali Tighnavard , Roshanghalb Shervin 
Published: June 2020

Abstract
Building Information Modeling (BIM) is a new paradigm in the architecture, engineering, and construction industry in Malaysia. In the literature, there are numerous reviews of BIM implementation on new buildings, while the BIM application in retrofitting existing buildings is rather disregarded yet. Only limited research has investigated the use of the potential of BIM in residential retrofit projects. This study seeks to investigate the current status of implementation of BIM for retrofitting residential buildings practicality. The research used the questionnaire as a quantitative method to collect data in the current study. One hundred twelve professionals were chosen for this study, and the response rate was 49 percent (55 respondents). The sample of the questionnaire survey consists of the academic experts and construction engineers and architects, BIM software designers, and construction organizations in Malaysia. The data collected through the respondents are analyzed using the Statistical Package for the Social Sciences software (SPSS Version 22). The results revealed that most of the respondents (47.3%) have a low level of awareness about BIM, and the majority of the respondents (29.1%) do not use BIM in their projects. Based on the investigation, the adoption of BIM residential buildings is timely. The most common obstacles to the BIM adoption for residential retrofit are the lack of customer demand, high initial investments, and lack of standards. In conclusion, this research provides information about the feasibility of BIM adoption for retrofitting the existing residential building. It is expected that this knowledge could be useful for BIM development and tackle barriers regarding BIM adoption in the Malaysia construction sector.
Sustainable residential building retrofit for improving energy efficiency: The owners’ perspective in Malaysia
Authors: Kermanshahi Emad Kasra , Tahir Mahmood Bin Md , Shukor Lim Nor Hasanah Abdul , Balasbaneh Ali Tighnavard , Roshanghalb Shervin 
Published: June 2020

Abstract
Malaysia has made continuous efforts to tackle energy sustainability challenges in recent years. There are significant opportunities to cut energy consumption and greenhouse gas emission (GHG) through retrofitting of existing domestic stocks. Due to the extremely fragmented nature of retrofit practice in the construction industry, there are some challenges among project stakeholders, including home occupants and builders in retrofitting residential buildings. There is a lack of research regarding the client’s requirements for housing retrofit priorities and preferences for retrofitting measures and materials. Therefore, the aim of this research is exploring the owner’s point of view for housing retrofit and their decision-making factors for choosing retrofit measures. In this study, by using sampling techniques, 400 people staying in Kuala Lumpur and Johor Bahru were selected for the housing retrofit preference survey. Statistical Package for the Social Sciences software (SPSS Version 22) was used as a statistical software to analyze survey data. It was revealed from the questionnaire survey that window/door is the top priority for clients to improve energy efficiency. Furthermore, the most critical factors in improving energy efficiency are initial cost and thermal performance, respectively. Moreover, in decision-making factors for selecting construction materials, owners emphasized on initial cost and payback time as important factors. Therefore, all experts in the construction industry should take into account the interests of customers with technical matters at the same time. In conclusion, this research empowers professionals to know homeowner needs and preferences from the beginning of retrofit projects.
BIM and CMMS for IBS building maintenance in Malaysia
Authors: Ismail Zul-Atfi , Abdul Rahim M. , Ghazaly Z. Md. 
Published: June 2020

Abstract
IBS construction is gradually increasing in many building projects in Malaysia. The projects have involved modern, contemporary and innovation design for construction. The increase of demands for IBS construction every year indirectly contributes the building and infrastructure development but maintenance management however is poor, possesses low defect diagnosis and limited decision making process to repairing. These problems become more complicated in complex and high-rise building projects like Malaysia to which IBS building construction is practiced. Conventionally, the repairing maintenance method (fragmentation approach) has been criticized for serious unacceptable quality or productivity, budget and concept of the IBS building maintainability (reworks and delay). Therefore, a novel and more sophisticated technique is proposed for improving defect diagnosis and decision making process by employing BIM and CMMS integration in maintenance management on IBS buildings in Malaysia.
Modulus of rupture and surface morphology of the cement composites with the addition of quarry dust
Authors: Madzura M , Mazlee M N 
Published: June 2020

Abstract
Quarry dust is widely used as a substitute material in the cement composites because of its strength, and at the same time the re-use of this by-product waste from the rock mining operations has led to the environmental awareness amongst the researchers all over the world. In this research, an experimental study was undertaken to find out the effect of quarry dust for varying percentage replacement of river sand on modulus of rupture of the cement composites. Besides that, this paper also aims at the relationship of the modulus of rupture and surface morphology of the cement composites. Properties of the cement composites are investigated with partial sand replacement with the addition of quarry dust at 10 wt.%, 12.5 wt.%, 15.0 wt.% and 17.5 wt.%. Cement composites were cured, tested for modulus of rupture and characterized for surface morphology at curing period of 7 and 28 days to obtain the optimal value of quarry dust in the cement composites. The results of this research have indicated that 12.5 wt.% of quarry dust exhibits the optimal value of modulus of rupture and surface morphology in satisfactory condition.
The effectiveness of oil palm shell (OPS) as major aggregate replacement in concrete
Authors: Abdul Rahman N , Tan A S H , Waqbitu F , Roslan N H 
Published: June 2020

Abstract
Malaysia known as one of global leaders in production and export of palm oil. This huge production of palm oil has produced high waste product which might cause to environmental pollution. The aim of this study is to determine the effectiveness of oil palm shell (OPS) as aggregate replacement in concrete and at the same time help to reduce the environmental pollution. The workability, density, and strength performances of concrete incorporated with 80% of OPS as coarse aggregate replacement were being investigated. Through the experimental test has shown that the OPS have high potential to be used as aggregate replacement in concrete. Furthermore, the experimental test results exhibited the advantage of OPS in reducing the density of concrete within 1800kg/m3 to 2000 kg/m3. However, the compressive strength of concrete containing OPS was decreased up to 35% from normal concrete strength. Thus, by introducing steel fibres into the OPS concrete has help in improving the concrete strength. Hence the additional of steel fibre into concrete has shown good potential in improving the lightweight concrete since it shows lower in density and 35% higher than minimum lightweight concrete strength as stated by ASTM C330-89.