bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Ignition and Combustion Characteristics of Al/NEPE Propellant
Authors: Zhuang Yuqian , Feng Yaya , Dong Longlong , Zhang Beichen , Ling Zhigang
Published: May 2022

In order to understand the ignition and combustion characteristics of Al particles in micron aluminized composite solid propellant under different pressures, the Al/NEPE propellant was tested on a laser ignition test system. By the means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and so on, the results indicate that the phenomenon of Al particles escaping from the combustion surface become more significant with the increase of pressure, and AlO gas intermediates exist during the combustion process of Al particles. The presence of oxide cap and broken agglomerates were observed and the influence of ambient pressure on size of Al agglomerates was illustrated by a laser particle size analyzer.
Numerical Investigation of Two-phase Unstable Combustion in High Temperature Rise Flame Tube
Authors: Long Wang , Ren Jiande , Cai Wenxiang , Chen Xiong
Published: May 2022

Intense acoustic pressure oscillation, caused by instability combustion, poses a huge challenge for the performance and the structural integrity of high temperature rise combustor. Transient process of combustion in the flame tube with three-stage axial swirler was investigated by numerical methods. Simulation results show that a wide range of velocity fluctuations appear at swirler’s outlet and recirculation zone move periodically at flame tube’s circumferential center plane, which cause the oscillation combustion.
A dual-mode hydrogen peroxide and kerosene space propulsion system pressurized by electric pumps
Authors: Zhou Chuang , Yu Nanjia , Li Tianwen , Gong Haojie
Published: May 2022

In this study, the performance characteristics and previous application cases of the dual-mode propulsion system (DMPS) were discussed. Besides, a dual-mode hydrogen peroxide and kerosene space propulsion system pressurized by electric pumps was proposed via the analysis of the existing problems with respect to the dual-mode propulsion system. In addition, the working process of this system was analyzed by system modeling and simulation. Further, the feasibility of DMPS was verified by exploring the working characteristics of the bipropellant main thruster and the monopropellant attitude control thruster. As per the analysis results, the DMPS proposed in this study contributed to eliminating the problems in the application of the dual-mode propulsion system at the present stage, and it also provided effective guidance in improving the performance of the propulsion system, adjusting the thrust flow rate, and making the propellant non-toxic.
Parameter optimization and simulation of lean-burn gas generator
Authors: Bo-wei JIAO , Nan-jia YU , Chuang ZHOU
Published: May 2022

The pre-cooling engine cools the incoming air through a pre-cooler and then makes it enter the subsequent components to work. This type of engine is one of the most important development directions in the combined power scheme. In order to accurately control the lean-burn gas temperature and oxygen concentration under different incoming flow conditions, and adjust it through the nitrogen-to-hydrogen ratio (GNGH) and oxygen-to-hydrogen ratio (GOGH). The oxygen concentration and temperature were obtained by thermal calculation and the optimal nitrogen-hydrogen ratio and oxygen-hydrogen ratio were optimized by genetic algorithm. Finally, the sensitivity analysis of the influence of nitrogen-hydrogen ratio and oxygen-hydrogen ratio on temperature and oxygen concentration was performed near the optimal point. According to the research, when α (weight coefficient) is determined, as the height increases, GNGH and GOGH decreases, and the amount of hydrogen required increases. When α > 1, the temperature term plays a major role in the optimization result. When α < 0.01, the oxygen concentration term plays a major role in the optimization result. When 0.01 < α < 1, the temperature term and oxygen concentration term are considered to have an effect on the optimization result at the same time. For the sensitivity analysis of the nitrogen-hydrogen ratio, oxygen-hydrogen ratio, temperature and oxygen concentration under different working conditions, accurate numerical results have also been obtained.
Analysis of Heavy Vehicle Research Status about Knowledge Structure and Research Hotspots Based on CiteSpace
Authors: Shao Tingting , Liu Shaohua
Published: May 2022

Heavy vehicle is an important carrier of cargo transportation and is always the research focus of the automotive and environment field. In this paper, the scientific metrological analysis method is used to systematically summarize the research topics and current situation of heavy vehicles. From 2000 to 2019, 1047 articles and 7259 references were investigated. The subject and subject of heavy vehicle research are determined. This paper makes an in-depth study on the phenomenon of citation burst. The research results of this paper not only provide practitioners with a deeper understanding of heavy vehicles, but also help researchers carry out relevant in-depth research.
Experimental research on carbonization of insulation and condensed particle deposition of SRJ combustion chamber
Authors: Zhao Jing-chao , Zhao Rui-jie , Cai Wen-xiang , Chen Xiong
Published: May 2022

Performance of boron-based solid rocket ramjet was carried out by the ground direct connection test rig. Through SEM and EDS analysis of condensed products on the insulation wall of the second combustion chamber, the change of carbonization structure of insulation and the deposition of condensed particles along the axis were researched. Experiment results show that porosity of the carbonized layer become larger and the structure becomes loose along flow direction. The deposition of condensed particles on the insulation wall is increased, and the deposition is obvious at nozzle entrance.
Research on Vertical Interconnection and Energy Conversion of Bridge Film
Authors: Li Liming , Zhang Jingxin , Li Jun
Published: May 2022

In this paper, a NiCr bridge film igniting component is designed. The film igniting component is fabricated by an integrated circuit process to complete the electrical connection of the bridge film igniting component and the side and bottom of the substrate. By placing the bridge film igniting component on the electrode plug, the bottom electrode is aligned with the top surface of the electrode plug upper surface to complete the connection between the bridge film igniting component and the electrode plug, and the conventionally connected wire bond is removed. Through the relationship between the adiabatic equation of the NiCr bridge film igniting component and the input electric energy, the theoretical relationship between the ignition time of the bridge film igniting Component and the input current is calculated, and the experimental test is verified.
Inner Sequential Single Solid Method for Layout Optimization of Multi-Materials
Authors: Cao Jing
Published: May 2022

In multiple materials layout optimization, the optimal solution is difficult to achieve due to the number of design variables being too large and the material interpolation scheme becoming complicated when using density-like method. To bypass this problem, an inner sequential single solid optimization (ISSSO) method is presented in this study. There are two types of iterations in the optimization process of this method: the inner and outer iterations. In the inner iteration, the original layout optimization of many materials is replaced with a series of single solid sub-optimizations. In each sub-optimization, only one solid is chosen to update and the rest keeps unchanged. The inner iteration stops when all the solids are updated consequently. The next loop of inner iteration starts when the current solution does not meet the requirement of convergence. The outer iteration starts only if the current inner iteration comes to an end. In the outer iteration, the new inner iterations for update of all the solid materials are carried out. The effectiveness of ISSSO method is verified by comparing the calculation results with other methods.
Study of Impingement Cooling Technology by Using Circular Pin Fins and Mist/Air Methods in Gas Turbine Combustor
Authors: Yu Zhenglei , Cao Qing , Liu Zhenze , Liu Bo
Published: May 2022

The gas turbine is an indispensable part of technology and it is commonly used in electric power, aviation and marine mechanical. However, the gas combustion temperature was higher than the melting point of metal, which prevents further increase in efficiency in a gas turbine. To enhance the turbine inlet temperature greatly, an advanced cooling technology has been essentially required to protect the material of high thermal components. The final numerical results are compare with each other and show the characteristics of heat transfer and pressure drop. In these investigations, different cases evaluate that the adiabatic cooling effectiveness (ηc
) indicates a downward curvature in the following descending order: circular pin fin with mist case = circular pin fin only case > normal with mist cooling case > normal with air only case. Mist/air impiangement cooling with circular pin fins not only maintain the superiorities of air cooling jets, but more effective than pin fins technique. Accordingly, renewing the air impingement cooling systems with pin fins and mist cooling seems to be more attractive. The inspire application of the circular pin fins and mist/air impingement cooling will make it a reference for designing a new cooling structure in marine gas turbine combustor.
An optimization model of cutting path and parameters for low cost and carbon emissions in a NC milling process
Authors: Yang Qingbin , Yin Ruixue , Li Chaowen , Feng Xuqing
Published: May 2022

Based on the analysis of the carbon emissions and the cost evaluation model for NC milling process, the impact of different tool cutting paths to carbon emissions is compared and analyzed. Taking both carbon emissions and cost of NC milling process as optimization goals, constraints are proposed based on machine parameters and processing quality requirements. The optimization model of cutting paths and parameters for low carbon emissions and cost of NC milling process is built where the spindle speeds, feed per tooth and transverse cutting depth are taken into account as optimization variables. An example is employed to validate the model. First, the cutting path of the tool is determined by experience and the cutting parameters are selected under the lowest carbon emissions and cost target. Secondly, the genetic algorithm is used to optimize the cutting paths based on the optimal cutting parameters.
Study of Direct-link Test of Oblique Detonation Engine
Authors: Chen Shuo , Ma Hu
Published: May 2022

Based on the shock tube wind tunnel driven by detonation, simulating the flight altitude of 30km and the incoming flow conditions of flight Mach number 9, this paper conducts a study of direct-link test of the oblique detonation engine with an oblique wedge angle of 30 degrees. The detonation process and stationing characteristics of the oblique detonation wave are analysed in detail by the engine wall pressure measurement combined with the high-speed camera for simultaneous shooting. During the test, the oblique detonation wave successfully detonates on the oblique wedge and is validly stationed. Under the collision effect of the shock waves system downstream the oblique wedge, the oblique detonation wave successfully detonates, and the oblique detonation wave spreads and develops upstream direction after the detonation, and finally, the oblique detonation wave is successfully stationed. Using shadow-graph method to observe the wave system in the combustion chamber, the typical flow field structure such as non-reactive shock wave, oblique detonation wave, transverse wave and triple point is clearly observed, and the angle of oblique detonation wave in the oblique detonation engine tested in this paper is greater than 80 degrees. The successful detonation and stationarity of oblique detonation wave in direct-link test proves the feasibility of oblique detonation wave to be applied to hypersonic propulsion.
Analysis of FSC Supercharged Engine Intake Front End
Authors: Xinyi Zheng , Wei Su
Published: May 2022

This paper is based on the simulation analysis of the supercharger front intake pipeline of the FSAE racing car engine. To limit engine power, the equation race requires an annular restrictor valve to be installed in the intake system with an inner diameter less than 20mm. Limiting valves have a great impact on the intake flow and engine performance. In this paper, the intake front segment is modeled, the simulation analysis is done by Fluent, and the GT-power engine simulation software is used to assist the simulation. A good intake front segment is obtained, which provides an effective method for the design of the intake front of supercharger engine.
Fast point cloud registration algorithm using parallel computing strategy
Authors: Feng-yuan SHI , Xun-jiang ZHENG , Li-hui JIANG , Di PAN , Bing LIU
Published: May 2022

At present, the traditional ICP (Iterative Closest Point) algorithm used by TOF (Time-Of-Flight) cameras has the problem of high time-consuming in nearest point search process, resulting in low data update rate. Therefore, based on the characteristics of the data structure of the ICP algorithm, a multi-stage pipeline acceleration system is proposed, and the point cloud registration algorithm used in this system is studied. Firstly, design multiple units to store point cloud data and serve as the main search module. Secondly, make each group of units perform parallel operations, input the stored point clouds into their respective calculation modules, select a model point, traverse all query points, and perform subtraction. Then replace the model point and repeat the process until all model points are calculated. Finally, the query point corresponding to the minimum value in each model point difference data is selected and the model point is output as a point pair to the CPU to complete the final algorithm iteration. The experimental results show that at 30000 points, a single closest point search takes 25.65ms; at 20000 points, a single closest point search takes 11.65ms; at 10000 points, a single closest point search takes 2.88ms. It basically meets the requirements of TOF camera on-orbit measurement for the stability and reliability of point cloud registration and high data update rate.
Polarization space time adaptive processing based on maximum likelihood polarization vector estimation
Authors: Zhongping HUANG , Zhiyong LEI , Zishu HE , Huiyong LI , Liang ZHANG , Haoliang SHEN
Published: May 2022

In airborne radar, signal to clutter plus noise ratio (SCNR) can be improved by utilizing polarization space time adaptive processing (PSTAP). The optimal output SCNR is obtained when the expected polarization-space-time (PST) vector matches the true value. The problem of polarization parameters estimation limits the potential application of PSTAP. The inaccuracy of polarization parameters estimation unevitably causes SCNR loss. In this paper, the effect of expected polarization vector on output SCNR is analyzed on the basis of PSTAP theory. In order to reduce SCNR loss introduced by polarization mismatch, an engineering PSTAP based on maximum likelihood method is proposed. Experimental data show that this method can accurately estimate the polarization parameters, improving SCNR about 2~3dB compared with the conventional STAP.
Micro-nano Satellite Phasing Maneuver Method under Microthrust Constraint
Authors: Chuang-ge WANG , Gen XU , Dan-he CHEN , Wen-he LIAO
Published: May 2022

The micro-thruster of micro-nano satellite cannot provide a large impulse for a single time to satisfy the requirements of the general phasing maneuver because of the constraints of thrust and the stability of attitude control system. A multi impulses phasing method is proposed based on the four impulses phasing maneuver, which satisfies the constraint of the working time of the micro thruster. In this method, a large impulse is divided into multiple small impulses, and the impulses can be re-optimized under the constraint of phasing time, which can realize the phasing maneuver of micro-nano satellites using microthrusters. The simulation results show that the error of phasing time is less than 30 s, and the phasing accuracy in two-body orbit dynamic is less than 0.2 km. Considering the perturbation and the error of the micro thruster, the phasing accuracy is less than 5 km, which meets the time limit and fuel consumption limit in phasing maneuver of the micro-nano satellite.
AIR TOUCH: Human Machine Interface Using Electromyography Signals
Authors: Sreyas S. , Kochuvila Sreeja , Vignesh S. , Pranav R.
Published: May 2022

Novel interactions between futuristic devices and humans in the ever-expanding digital world is gaining momentum in the current era. In this paper, a system is proposed where electromyography (EMG) signals are used to control the cursor on a PC with the movement of the hand, making effortless interaction between user and the computer. The hand movements are detected using accelerometer and EMG signals acquired using electrodes are used to classify the hand gestures. Time domain features are extracted from the EMG signals and the gestures are classified using K-Nearest Neighbor (KNN) classifier. The operation to be performed on PC is determined from the gesture with help of a suitable interface. This system is implemented to perform the positioning of the cursor and two of the most common actions of a mouse, namely, single click and double click. The system showed an accuracy of 98% in classifying the gestures.
Robotic arm for brake performance testing
Authors: Shirose Burhanuddin , Yadav Kunal , Meenatchi LS , Vedhanarayan K
Published: May 2022

Bikes require their brakes to be tested. There are adequately defined conditions under which these tests need to be performed: the brake pedal has to be pressed by a constant force. This force varies depending on the standardized test, but the value remains constant under each standard. No bike brake is perfect and thus has imperfections like disc thickness variation and disc misalignment. These imperfections cause judder due to which force experienced by the brakes under a specific pedal position varies too. This can create errors in tests and thus needs to be overcome for proper performance testing of brakes. “Robotic arm for brake performance testing” provides an effective solution by constantly measuring the braking force and instantly moving the brake pedal to keep the braking force constant.
The Design of an Intelligent Chatbot with Natural Language Processing Capabilities to Support Learners
Authors: Wong A
Published: May 2022

It would be ideal for the teacher to give individual attention to each student. However, this is infeasible as teachers only have limited time and they will be tired after long periods of consultation. Chatbots can be an effective tool to overcome this problem. A pilot was conducted on 11 Feb 2019 in which 27 students tried a chatbot prototype built by the author. The students compared the chatbot and a quiz website. The academic contents provided by the chatbot are exactly the same as the website. Over 80% of the students agreed that the chatbot is better than the quiz website in many aspects. However, about half of the students also indicated that the chatbot took them more time to complete the quiz than the quiz website. The author proposed using the Unified Theory of Acceptance and Use of Technology (UTAUT) framework to conduct more research into this area. The knowledge would allow more teachers to create chatbots in more disciplines of study so that students are more motivated to achieve the learning outcomes better.
DograNet – a comprehensive offline dogra handwriting character dataset
Authors: Kumar J , Roy A
Published: May 2022

Handwritten Text Recognition is an important area of research because of growing demand to process and convert a huge data and information available in handwritten form to Digital form. The digital data instead of handwritten form can prove to be highly useful in different fields. Handwritten text recognition plays an important role in applications involved in, postal services, banks for cheque processing, searching of information and organization dealing with such applications. In text recognition application dataset of the specified script is required for training purpose. Datasets of the different languages could be found online but dataset of dogra script characters is still not available. This paper presents a Dogra handwriting character dataset which contains around 38690 character images etc grouped in 73 character classes extracted from 530 one-page handwritings of 265 individuals of having variable age, sex, qualification, location. The dogra character dataset would be freely accessible by scholars and researchers which could also be used for further recognition improvement and updating with more characters and word, Identification of writer, dogra word segmentation. Dogra dataset could also be used for extracting variation of handwriting according to age and gender.
Mathematical Model for Field Data Based for Productivity Enhancement of Cylinder Head Moulding Operation
Authors: Zakiuddin Kazi Syed , Bachute Rahul , Zahiruddin Quazi Syed
Published: May 2022

The paper illustrates with an approach for formulation of generalized field data based model for cylinder head moulding operation. The aim of field data based modeling for cylinder head moulding operation is to evaluate variable responsible for productivity enhancement & with minimum human energy expenditure. The study identifies important ergonomic and other work environment related parameters which affect the productivity. The identified parameters are properties of sand, physical dimensions of tools, energy outflow of workers, workers anthropometric data, working environment. Out of all the variables responses and causes are identified.

After dimensional analysis relationship between the dependent and independent parameters, a mathematical model is established having relationship between output parameters and input. To get the optimized values model is optimized using the optimization technique. Sensitivity analysis is a tool which can be used to find out the effect of input one parameter over the other. The model will be useful for an industrialist to select optimized inputs so as to get targeted responses.
Measurement of high-pressure xenon gas absorption in acrylic
Authors: Lin H. , Ni K. , Du H. , Han K. , Ji X. , Li T. , Luo L. , Wang S. , Yan X. , Zeng X. , Zhang W.
Published: May 2022

Acrylic is a popular structural material in experiments
requiring low background because of its radio-purity, machinability,
and mechanical strength. However, its porosity may cause
significant gas absorption and influence the detector stability in
the long term. The interaction between acrylic and other detector
materials becomes one of the key concerns in the detector design.
In this paper, we carry out an experiment to measure quantitatively
the absorption process of high-pressure xenon gas into acrylic. A
specific setup is designed for the measurement, and systematic
measurements are done to obtain a result of the absorption amount:
0.98 g xenon into 332 g of acrylic.
Evaluation of the Constant Fraction Time-Over-Threshold (CF-TOT) method for neutron-gamma pulse shape discrimination
Authors: Roy A. , Vartsky D. , Mor I. , O. Cohen E. , Yehuda-Zada Y. , Beck A. , Arazi L.
Published: May 2022

The use of Time-over-Threshold (TOT) for the discrimination
between fast neutrons and gamma-rays is advantageous when large
number of detection channels are required due to the simplicity of
its implementation. However, the results obtained using the
standard, Constant Threshold TOT (CT-TOT) are usually inferior to
those obtained using other pulse shape discrimination (PSD) methods,
such as Charge Comparison or Zero-Crossing approaches, especially
for low amplitude neutron/gamma-ray pulses. We evaluate another TOT
approach for fast neutron/gamma-ray PSD using Constant-Fraction
Time-over-Threshold (CF-TOT) pulse shape analysis. The CT-TOT and
CF-TOT methods were compared quantitatively using digitized
waveforms from a liquid scintillator coupled to a photomultiplier
tube as well as from a stilbene scintillator coupled to a
photomultiplier tube and a silicon photomultiplier. The quality of
CF-TOT neutron/gamma-ray discrimination was evaluated using Receiver
Operator Characteristics curves and the results obtained with this
approach were compared to that of the standard CT-TOT method. The
CF-TOT PSD method results in > 99.9% rejection of gamma-rays with
> 80% neutron acceptance, much better than CT-TOT.
Estimating curvilinear self-motion from optic flow with a biologically inspired neural system*
Authors: Layton Oliver W , Powell Nathaniel , Steinmetz Scott T , Fajen Brett R
Published: May 2022

Optic flow provides rich information about world-relative self-motion and is used by many animals to guide movement. For example, self-motion along linear, straight paths without eye movements, generates optic flow that radiates from a singularity that specifies the direction of travel (heading). Many neural models of optic flow processing contain heading detectors that are tuned to the position of the singularity, the design of which is informed by brain area MSTd of primate visual cortex that has been linked to heading perception. Such biologically inspired models could be useful for efficient self-motion estimation in robots, but existing systems are tailored to the limited scenario of linear self-motion and neglect sensitivity to self-motion along more natural curvilinear paths. The observer in this case experiences more complex motion patterns, the appearance of which depends on the radius of the curved path (path curvature) and the direction of gaze. Indeed, MSTd neurons have been shown to exhibit tuning to optic flow patterns other than radial expansion, a property that is rarely captured in neural models. We investigated in a computational model whether a population of MSTd-like sensors tuned to radial, spiral, ground, and other optic flow patterns could support the accurate estimation of parameters describing both linear and curvilinear self-motion. We used deep learning to decode self-motion parameters from the signals produced by the diverse population of MSTd-like units. We demonstrate that this system is capable of accurately estimating curvilinear path curvature, clockwise/counterclockwise sign, and gaze direction relative to the path tangent in both synthetic and naturalistic videos of simulated self-motion. Estimates remained stable over time while rapidly adapting to dynamic changes in the observer’s curvilinear self-motion. Our results show that coupled biologically inspired and artificial neural network systems hold promise as a solution for robust vision-based self-motion estimation in robots.
The roles of global warming and Arctic Oscillation in the winter 2020 extremes in East Asia
Authors: Kim So-Hee , Kryjov Vladimir N , Ahn Joong-Bae
Published: May 2022

The 2019/20 winter was extremely warm globally and in the Northern Hemisphere extratropics. The main cause of climate extremes particularly in East Asia, was the extreme positive Arctic Oscillation (AO) event superimposed on steady global warming. The negligible trend in the AO over the preceding 41 years makes it possible to distinguish the roles of AO and global warming in the observed extremes. We estimate and compare contributions to January–March 2020 climate extremes by the AO and global warming represented by local temperature trends using the ERA5 reanalysis data. Based on results from a preliminary study, we estimate the contribution by global warming using linear regression while that by the AO using cubic regression, which is more restrained for the high AO index values than linear. The results show that the temperature extremes were mainly caused by the extreme positive AO event which accounts for approximately 3/4 of the observed temperature anomalies in northern East Asia and 2/3 in eastern East Asia. In southern East Asia, the AO contributes negligibly and positive temperature anomalies are related to global warming and local and regional impacts, particularly extreme sea surface temperature, enhance south-westerlies and local radiative forcing. General conclusion is that the observed strong positive temperature anomalies including extreme anomalies over East Asia could have been achieved only as a combined effect of the extreme positive AO event and global warming. Quantification of the roles of the AO and global warming in climate extremes helps to estimate future anomalies caused by extreme AO events as well as assess uncertainties in climate model projections.
Enhanced monitoring of atmospheric methane from space over the Permian basin with hierarchical Bayesian inference
Authors: Roberts Clayton , Shorttle Oliver , Mandel Kaisey , Jones Matthew , Ijzermans Rutger , Hirst Bill , Jonathan Philip
Published: May 2022

Methane is a strong greenhouse gas, with a higher radiative forcing per unit mass and shorter atmospheric lifetime than carbon dioxide. The remote sensing of methane in regions of industrial activity is a key step toward the accurate monitoring of emissions that drive climate change. Whilst the TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinal-5P satellite is capable of providing daily global measurement of methane columns, data are often compromised by cloud cover. Here, we develop a statistical model which uses nitrogen dioxide concentration data from TROPOMI to efficiently predict values of methane columns, expanding the average daily spatial coverage of observations of the Permian basin from 16% to 88% in the year 2019. The addition of predicted methane abundances at locations where direct observations are not available will support inversion methods for estimating methane emission rates at shorter timescales than is currently possible.
Grassy–herbaceous land moderates regional climate effects on honey bee colonies in the Northcentral US
Authors: Quinlan Gabriela M , Sponsler Douglas , Gaines-Day Hannah R , McMinn-Sauder Harper B G , Otto Clint R V , Smart Autumn H , Colin Théotime , Gratton Claudio , Isaacs Rufus , Johnson Reed , Milbrath Meghan O , Grozinger Christina M
Published: May 2022

The lack of seasonally sustained floral resources (i.e. pollen and nectar) is considered a primary global threat to pollinator health. However, the ability to predict the abundance of flowering resources for pollinators based upon climate, weather, and land cover is difficult due to insufficient monitoring over adequate spatial and temporal scales. Here we use spatiotemporally distributed honey bee hive scales that continuously measure hive weights as a standardized method to assess nectar intake. We analyze late summer colony weight gain as the response variable in a random forest regression model to determine the importance of climate, weather, and land cover on honey bee colony productivity. Our random forest model predicted resource acquisition by honey bee colonies with 71% accuracy, highlighting the detrimental effects of warm, wet regions in the Northcentral United States on nectar intake, as well as the detrimental effect of years with high growing degree day accumulation. Our model also predicted that grassy–herbaceous natural land had a positive effect on the summer nectar flow and that large areas of natural grassy–herbaceous land around apiaries can moderate the detrimental effects of warm, wet climates. These patterns characterize multi-scale ecological processes that constrain the quantity and quality of pollinator nutritional resources. That is, broad climate conditions constrain regional floral communities, while land use and weather act to further modify the quantity and quality of pollinator nutritional resources. Observing such broad-scale trends demonstrates the potential for utilizing hive scales to monitor the effects of climate change on landscape-level floral resources for pollinators. The interaction of climate and land use also present an opportunity to manage for climate-resilient landscapes that support pollinators through abundant floral resources under climate change.
Operator spreading in the memory matrix formalism
Authors: McCulloch Ewan , von Keyserlingk C W
Published: May 2022

The spread and scrambling of quantum information is a topic of considerable current interest. Numerous studies suggest that quantum information evolves according to hydrodynamical equations of motion, even though it is a starkly different quantity to better-known hydrodynamical variables such as charge and energy. In this work we show that the well-known memory matrix formalism for traditional hydrodynamics can be applied, with relatively little modification, to the question of operator growth in many-body quantum systems. On a conceptual level, this shores up the connection between information scrambling and hydrodynamics. At a practical level, it provides a framework for calculating quantities related to operator growth like the butterfly velocity and front diffusion constant, and for understanding how these quantities are constrained by microscopic symmetries. We apply this formalism to calculate operator-hydrodynamical coefficients perturbatively in a family of Floquet models. Our formalism allows us to identify the processes affecting information transport that arise from the spatiotemporal symmetries of the model.
Responsive Design Approach towards the Sustainable Mosque Architecture
Authors: Syaheera Aziz Nurul , Sabrina Ismail Alice , Siraj Suhailah
Published: May 2022

This paper’s primary purpose is to design a sustainable mosque for communal development that adapts to the surrounding area. The National Mosque and The Mizan Mosque were selected as prominent case studies emphasizing the study of form and space. Thus, this study summaries new ways of describing mosque design, using structural and semiotic paradigms as a methodological approach to studying the relationship between mosque design and sustainable aspects. The guidelines developed from this study are helpful for designers, builders, developers and relevant authorities to build mosques as sustainable community development in the future.
Community Perception on ‘Third Place’ Generation and Planning for Enhanced Neighbourhood Interaction at Pengkalan Kubor, Malaysia
Authors: Iqmal Mohd Azamli Muhammad , Sabil Azmal , Abdul Rahim Asiah , Asif Nayeem , Ismail Jamail Maliza
Published: May 2022

Pengkalan Kubor at the east coast of Peninsular Malaysia is affected by limited neighbourhood interaction and liveability. A proper and good place is essential for neighbourhood interaction. There is a lack of places for social interaction, and the existing places are in poor condition and maintenance. This research aims to evaluate the impact of generating the “Third Place” to enhance neighbourhood interaction at Pengkalan Kubor. This paper seeks to identify the factors that obstruct neighbourhood interaction and evaluate the effectiveness of third place to resolve the neighbourhood interaction and improve the study context’s liveability. The questionnaire survey used for this research evaluates neighbourhood interaction. Since the study area is in Pengkalan Kubor, the respondents selected for this study were within the community. In addition to defining the neighbourhood, the survey defined the third places within the study context. The findings from the public perception of neighbourhood interaction and third place at Pengkalan Kubor may be useful for many stakeholders for public places’ future planning.
Economic Model of Green Building Construction: A Conceptual Model
Authors: Ahmad Zaini Afzan , Khairina Khairul Hisham Nur , Rashid Abdul Aziz Abdul , Nadia Abd Aziz Nurul
Published: May 2022

The current research shows that green building received inadequate support from industry parties due to its high up-front cost. There are no existing guidelines focussing on how to minimize the issues of high up-front cost and for that reason, not all clients willing to get involved in green building construction. Hence, to increase their interest in investing in the green building, this research aims at formulating an economic model of green building construction using Structural Equation Modelling (SEM). The objectives of this research are to identify the green buildings elements, examine the most expensive elements, recommend the strategies in minimizing the cost of green building construction and to formulate and validate an economic model of green building construction. The model is one of the strategies to minimize the total cost, increase the client’s interest to invest in green building as well as facilitate construction stakeholders from inception to completion stage; in line with the Twelve Malaysia Plan “Economic Empowerment and Environmental Sustainability”.
A systematic review of studies examining the relationship between resilience and physical asset management for water system
Authors: Rozman AT , Jiram W R A , Rahman M S A , Ismail A , Azmi N A
Published: May 2022

The resilience in the water system can produce great benefits; one of the ideal ways to achieve resilience is through asset management. The purpose of this study is to systematically review the literature that presents the relationship between asset management and resilience. We searched multiple databases such as Emerald Insight, Sage Publication, Science Direct, Scopus, Taylor and Francis, and Wiley Online Library ranging from the year 2000 until the year 2020. The papers are written in English. A total of 7845 articles have been successfully identified and only 6 papers met the inclusion criteria of the study. The study has concluded that most of the previous research that discusses asset management and resilience are in groups dating 5 years back (2015-2019). Several features of physical asset management require further investigation that can enhance the resilience of the water system. The topic is relatively new and hopes to open a huge gap for research.
Reliability of 15-minute drone footage volume for estimating urban traffic flow rates: A preliminary study
Authors: Abdullah M S , Sanik M E , Mat Nor A H , Salim S , Abdul Malek K Z , Razali N F , Mohd Nasir A Z
Published: May 2022

This study discusses the reliability of 15-minute data collection from the drone footage as an alternative for conventional 1-hour data collection for traffic analysis. The selected study locations are five urban intersections along Jalan Bakri, Muar, Johor. The 12-hour data was obtained from a manual commuter counting to identify the peak hour along Jalan Bakri. Based on the time series analysis, the peak hour was identified which is from 5.30 to 6.30 p.m. with a peak hour factor of 0.94. The actual flow rate during peak hour and the volume from 15-minute drone footage multiply by 4 and peak hour factor value were compared using the t-test. The P-value obtained is 0.732 which is greater than 0.05 for 95 percent confidence Therefore, the difference between the means is not statistically significant. In summary, there is evident to prove that the outcome from the drone footage data during the peakiest 15-minute interval has no significant difference with the outcome from 1-hour data collection during peak hour. This verification result shows that the 15-minute data collection during peak hour can be applied to facilitate the intersection performance analysis besides can enhance the use of drone in traffic study.
Numerical analysis of embankment resting on floating bottom ash columns improved soft soil
Authors: Abbil A , Kassim A , Ullah A , Rashid A S A , Roshan M. J.
Published: May 2022

The construction of embankment over soft clay is quite a challenging job for the geotechnical engineer, which may results in a large settlement, bearing failure and stability issues. Stone columns can be used to minimize the settlement and increase the bearing capacity in such conditions. This study was carried out to investigate the behaviour of bottom ash columns underneath embankments using numerical modelling. The soft soil improved with bottom ash columns under the embankment subjected to traffic-induced loading was simulated in Plaxis 3D foundation software. The study variables include three area replacement ratios (Ar) of 10%, 15% and 20% and two columns length of 5m and 7.5m. The results indicated that enlarging the Ar and length of columns significantly reduced the final settlement and consolidation time. The maximum settlement reduction of 58% was reported for the Ar of 20% with 7.5m column depth. The study suggests that bottom ash columns can be used to improve soft soil underneath the embankment.
Investigating the Properties of Asphalt Mixes Containing Recycled Polyethylene Terephthalate Fiber
Authors: Aman M Y , Taher M N M , Shahadan Z , Rohani M M , Daniel D B
Published: May 2022

A large volume of traffic loading on asphalt pavement at high temperature frequently resulted in pavement deterioration due to reduction in strength and loss of structural integrity. This paper presents the effects of recycled polyethylene terephthalate fiber used in the ranges of 1.18 mm to 2.36 mm prepared for 0%, 0.5% and 1.0% by the weight of mineral aggregates. Conventional bitumen 60/70 penetration grade was used as the base binder. The compacted specimens were tested for dynamic creep, resilient modulus and resistance to rutting. It was found that the creep stiffness specimens prepared with 0.5% recycled polyethylene terephthalate fiber tested at 1800 and 3600 load cycles has increased by 11.7% and 23.8%, moreover permanent deformation has reduced by 8.7% and 8.4%, respectively. Furthermore, specimens containing 0.5% recycled polyethylene terephthalate fiber also has increased the resilient modulus by 10.0% and 55.1% while the rutting values decreased by 13.7% and 13.9%, correspondingly. Interestingly, specimens containing 0.5% recycled polyethylene terephthalate fiber exhibits higher mixes stiffness, low rutting and permanent deformation irrespective of test temperature. It can be concluded that specimen containing 0.5% recycled polyethylene terephthalate fiber contributes higher resistance to rutting, promotes better performance compared to conventional mix.
Simulating the Impact of Vehicle Speed on the Life of Bituminous Pavement
Authors: Imran Khan Muhammad , Yusrina Binti Zainal Abidin Siti , Hartadi Sutanto Muslich , Wong Fadhli , Bujang Mastura
Published: May 2022

Due to the visco-elastic nature, the performance of flexible pavements depends on temperature and loading conditions. This study investigates the influence of different speeds of vehicle and binder type on stiffness modulus and the corresponding pavement life. The filed data was collected from the pavement section at Bukit Mertajam, Penang, Malaysia. The data were used to determine the stiffness of binder and corresponding stiffness of wearing and binder courses at different vehicle speeds (30, 50, 70 and 80 km/h) using analytical equations. The data of layer properties (stiffness and poison’s ratio) and axle loading (wheel load, tyre configuration) were incorporated in BISAR software to determine the horizontal tensile strain at bottom of binder layer and vertical compressive strain at top of subgrade. The strains were then used to predict pavement life passed on fatigue and rutting failure criteria. It was concluded that increasing the speed of the vehicle (from 30 km/h to 80 km/h) causes about 24% increase in stiffness modulus of wearing course. Similarly, asphalt mixture with Pen 80/100 grade bitumen has a lower stiffness modulus than Pen 60/70 grade bitumen. Furthermore, reducing vehicle speed (i.e., increasing loading time) causes a reduction in fatigue and rutting life of the pavement. Therefore, it is required to consider the speed of the vehicle while designing flexible pavement in addition to other mixed design considerations.
Performance-Driven Evaluation and Parametrical Design Approach for Sustainable Complex-Tall Building Design at Conceptual Stage
Authors: Alkhatib F H , Kasim N , Goh W I , Al-masoodi A H H
Published: May 2022

Tall buildings with irregular forms are gaining popularity in creating the vertical city model, and they are designed and built today with the help of computational technologies. This paper aims to highlight the significant link between the architectural and structural conceptual design of tall buildings with irregular geometries by using performance-driven evaluation and parametric design approach at conceptual stage to develop a sustainable design. Initially the review of previous research shows how the form of tall building is be defined. Furthermore, the parametric design approach is investigated for generating alternative options to satisfy building aesthetic and structural performance criteria with the aid of aerodynamic optimization technicque to generate an optimum solution for decision-making at an early stage, as well as allowing modifications in the later stages of design, and making it possible to handle the design process in a repetitive manner. Finally, a framework is proposed where computational techniques are integrated and an effective collaboration between professional designers is achieved in order to produce an optimal complex-tall building conceptual design that is architecturally pleasing, structurally efficient, and environmentally sustainable.
A Review of Strength Performance of Empty Fruit Bunch as Replacement Material in Building Structures
Authors: Omar M F , Hamid N A A , Othman N H , Ayop S S , Sulaiman N
Published: May 2022

Recently, eco-friendly construction has become a hot topic. One of the concepts’ alternatives is the use of green natural resources. The oil palm Empty Fruit Bunch (EFB) is a byproduct of the oil plantation, and its improper disposal can have a detrimental influence on the environment. Agricultural waste can be used as a replacement material in concrete, which is known as modified concrete. The material performance of modified concrete with partial waste material replacement must be comparable to that of ordinary concrete. As a result, the use of raw resources will be reduced indirectly, and the material will become a more sustainable construction material. This study presents the utilization of EFB natural fibre as an alternative building material. It demonstrates that research into employing EFB as alternative replacement material in concrete has yet to be discovered. EFB was primarily used to manufacture cement board, roof insulation, and cement bricks, among other things. As a result, future research should focus on expanding the use of these by-products in the building industry. Further research into the process of generating cost-effective adoption applications will be examined to build a sustainable environment by lowering negative environmental impact.