bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen vacancy dynamics in Pt/TiOx/TaOy/Pt memristors: exchange with the environment and internal electromigration
Authors: Leal Martir Rodrigo , José Sánchez María , Aguirre Myriam , Quiñonez Walter , Ferreyra Cristian , Acha Carlos , Lecourt Jerome , Lüders Ulrike , Rubi Diego
Published: November 2022

Memristors are expected to be one of the key building blocks for the development of new bio-inspired nanoelectronics. Memristive effects in transition metal oxides are usually linked to the electromigration at the nanoscale of charged oxygen vacancies (OV). In this paper we address, for Pt/TiO
x
/TaO
y
/Pt devices, the exchange of OV between the device and the environment upon the application of electrical stress. From a combination of experiments and theoretical simulations we determine that both TiO
x
and TaO
y
layers oxidize, via environmental oxygen uptake, during the electroforming process. Once the memristive effect is stabilized (post-forming behavior) our results suggest that oxygen exchange with the environment is suppressed and the OV dynamics that drives the memristive behavior is restricted to an internal electromigration between TiO
x
and TaO
y
layers. Our work provides relevant information for the design of reliable binary oxide memristive devices.
Precision of the PET activity range during irradiation with 10C, 11C, and 12C beams
Authors: Kostyleva D , Purushothaman S , Dendooven P , Haettner E , Geissel H , Ozoemelam I , Schuy C , Weber U , Boscolo D , Dickel T , Drozd V , Graeff C , Franczak B , Hornung C , Horst F , Kazantseva E , Kuzminchuk-Feuerstein N , Mukha I , Nociforo C , Pietri S , Reidel C A , Roesch H , Tanaka Y K , Weick H , Zhao J , Durante M , Parodi K , Scheidenberger C
Published: November 2022

Objective. Beams of stable ions have been a well-established tool for radiotherapy for many decades. In the case of ion beam therapy with stable 12C ions, the positron emitters 10,11C are produced via projectile and target fragmentation, and their decays enable visualization of the beam via positron emission tomography (PET). However, the PET activity peak matches the Bragg peak only roughly and PET counting statistics is low. These issues can be mitigated by using a short-lived positron emitter as a therapeutic beam. Approach. An experiment studying the precision of the measurement of ranges of positron-emitting carbon isotopes by means of PET has been performed at the FRS fragment-separator facility of GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany. The PET scanner used in the experiment is a dual-panel version of a Siemens Biograph mCT PET scanner. Main results. High-quality in-beam PET images and activity distributions have been measured from the in-flight produced positron emitting isotopes 11C and 10C implanted into homogeneous PMMA phantoms. Taking advantage of the high statistics obtained in this experiment, we investigated the time evolution of the uncertainty of the range determined by means of PET during the course of irradiation, and show that the uncertainty improves with the inverse square root of the number of PET counts. The uncertainty is thus fully determined by the PET counting statistics. During the delivery of 1.6 × 107 ions in 4 spills for a total duration of 19.2 s, the PET activity range uncertainty for 10C, 11C and 12C is 0.04 mm, 0.7 mm and 1.3 mm, respectively. The gain in precision related to the PET counting statistics is thus much larger when going from 11C to 10C than when going from 12C to 11C. The much better precision for 10C is due to its much shorter half-life, which, contrary to the case of 11C, also enables to include the in-spill data in the image formation. Significance. Our results can be used to estimate the contribution from PET counting statistics to the precision of range determination in a particular carbon therapy situation, taking into account the irradiation scenario, the required dose and the PET scanner characteristics.
Development and implementation of a metaphase DNA model for ionizing radiation induced DNA damage calculation
Authors: Sitmukhambetov Satzhan , Dinh Bryan , Lai Youfang , Banigan Edward J , Pan Zui , Jia Xun , Chi Yujie
Published: November 2022

Objective. To develop a metaphase chromosome model representing the complete genome of a human lymphocyte cell to support microscopic Monte Carlo (MMC) simulation-based radiation-induced DNA damage studies. Approach. We first employed coarse-grained polymer physics simulation to obtain a rod-shaped chromatid segment of 730 nm in diameter and 460 nm in height to match Hi–C data. We then voxelized the segment with a voxel size of 11 nm per side and connected the chromatid with 30 types of pre-constructed nucleosomes and 6 types of linker DNAs in base pair (bp) resolutions. Afterward, we piled different numbers of voxelized chromatid segments to create 23 pairs of chromosomes of 1–5 μm long. Finally, we arranged the chromosomes at the cell metaphase plate of 5.5 μm in radius to create the complete set of metaphase chromosomes. We implemented the model in gMicroMC simulation by denoting the DNA structure in a four-level hierarchical tree: nucleotide pairs, nucleosomes and linker DNAs, chromatid segments, and chromosomes. We applied the model to compute DNA damage under different radiation conditions and compared the results to those obtained with G0/G1 model and experimental measurements. We also performed uncertainty analysis for relevant simulation parameters. Main results. The chromatid segment was successfully voxelized and connected in bps resolution, containing 26.8 mega bps (Mbps) of DNA. With 466 segments, we obtained the metaphase chromosome containing 12.5 Gbps of DNA. Applying it to compute the radiation-induced DNA damage, the obtained results were self-consistent and agreed with experimental measurements. Through the parameter uncertainty study, we found that the DNA damage ratio between metaphase and G0/G1 phase models was not sensitive to the chemical simulation time. The damage was also not sensitive to the specific parameter settings in the polymer physics simulation, as long as the produced metaphase model followed a similar contact map distribution. Significance. Experimental data reveal that ionizing radiation induced DNA damage is cell cycle dependent. Yet, DNA chromosome models, except for the G0/G1 phase, are not available in the state-of-the-art MMC simulation. For the first time, we successfully built a metaphase chromosome model and implemented it into MMC simulation for radiation-induced DNA damage computation.
Foundations of plasmas as ion sources
Authors: Jorns Benjamin , Lafleur Trevor
Published: November 2022

An overview of low temperature, partially magnetized ion sources is presented. This class of devices is broadly characterized by plasma densities below 1019 m−3, electron temperatures below 100 eV, and magnetic field strength tailored such that electrons are magnetized whereas ions are not. The overarching approach is pedagogical, targeting an audience that does not necessarily have an expertise in low temperature devices. A tutorial is presented on the basic physics of operation of common ion sources including an overview of standard methods for plasma generation and acceleration. Typical diagnostics and common uses of these plasma sources are also reviewed. Special attention is given to applications in plasma propulsion and materials processing. This class of ion sources is then discussed in the context of the current state of the field, key technical and scientific challenges, and future prospects.
Smart material and design solutions for protective headgears in linear and oblique impacts: column/matrix composite liner to mitigate rotational accelerations
Authors: Mosleh Yasmine , Cajka Martin , Depreitere Bart , Ivens Jan , Sloten Jos Vander
Published: November 2022

Oblique impact is the most common situation that cyclists experience during traffic accidents during which the human head undergoes both linear and rotational (angular) accelerations. Angular acceleration of the head is known to be linked to the majority of traumatic brain injuries. This paper proposes various solutions to mitigate angular accelerations of which an anisotropic column/matrix composite foam design is the most effective. This smart design allows tailor-made adjustment of shear and compressive resistance of the foam liner. Regarding helmet shells, tough fiber-reinforced composite materials such as self-reinforced polypropylene (PP) (Curv®) and silk/high-density polyethylene (HDPE) were benchmarked against conventional brittle polycarbonate (PC). Results demonstrate the superior performance of silk/HDPE composite compared to PC in resisting perforation in localized impact involving sharp objects. Regarding the helmet liner, two configurations were studied particularly, a multi-layered and column/matrix design. Their efficacy was benchmarked against single-layer homogenous expanded polystyrene (EPS) foam of equivalent weight and thickness in linear and oblique impact using experimental and finite element methods. The results showed the superior behavior of the column/matrix configuration. Such smart design could be combined with other smart systems such as multi-directional impact protection system (MIPS) technology for possible synergy and enhanced performance in head protection.
Computational design and fabrication of active 3D-printed multi-state structures for shape morphing
Authors: Lumpe Thomas S , Tao Michael , Shea Kristina , Levin David I W
Published: November 2022

Active structures can change their shape, properties, and functionality as a response to changing operational conditions, which makes them more versatile than their static counterparts. However, most active structures currently lack the capability to achieve multiple, different target states with a single input actuation or require a tedious material programming step. In this work, a computational design and fabrication framework is proposed to generate structures with multiple target states for one input actuation that do not require a separate training step. A material dithering scheme based on multi-material 3D printing is combined with locally applied copper coil heating elements and sequential heating patterns to control the thermo-mechanical properties of the structures and switch between the different deformation modes. A novel topology optimization approach based on power diagrams is used to encode different target states in the structure while ensuring the fabricability of the structures. The numerical and experimental results show that the optimization framework can produce structures that show the desired motion, but experimental accuracy is limited by current fabrication methods. The generality of the proposed method makes it suitable for the development of structures for applications in many different fields from aerospace to robotics to animated fabrication in computer graphics.
Investigation into accuracy of turn-to-turn contact resistance measurement in low-frequency AC method by 3D numerical simulation
Authors: Mato Takanobu , Inoue Ryota , Ueda Hiroshi , Kim SeokBeom , Noguchi So
Published: November 2022

In this paper, we discuss two points: (a) the accuracy of contact resistance measurement using the low-frequency AC (LFAC) method and (b) the relation between the contact resistance and the contact resistivity. The LFAC method is used to measure the turn-to-turn contact resistance of a no-insulation (NI) rare-earth barium copper oxide (REBCO) pancake coil. We have previously shown the validity of the LFAC method by experiment. In this paper, the current distribution of aNI REBCO pancake coil on the applyication of the LFAC method is investigated using numerical simulation. The simulation results show the possibility of improving the measurement accuracy. Hence, a correction method is also proposed using the phase difference of the coil voltage and current. The LFAC simulation results also indicate the inconsistency of the well-known relation between contact resistance and contact resistivity. Therefore, we investigated the relation through the LFAC and sudden-discharging test simulations.
Quantum occupation time
Authors: Potoček Václav , Zatloukal Václav
Published: November 2022

We present a possible quantum analogue of occupation time, a random variable studied in random processes, using a quasi-probability distribution over the sample space of quantum particle paths defined by a generalized weak measurement scheme. Taking this approach, a broad range of statistical properties of quantum occupation time can be studied. We illustrate the theory on a discrete-time quantum walk on a line, where we derive two novel results. We introduce the notions of weak recurrence, weak Pólya number, and weak occupation time plateau.
Prolongation structure and integrability of the modified Sawada-Kotera equation
Authors: Zhu Xiaodong
Published: November 2022

The modified Sawada-Kotera equation is investigated by prolongation technique and Painlevé singularity analysis. As a result, the Lax pair and conservation laws of the modified Sawada-Kotera equation are formulated. It is proved that this equation pasts the Painlevé test in sense of having enough arbitrary functions at its resonant points. The auto-Bäcklund transformation and exact solutions of the modified Sawada-Kotera equation are obtained explicitly.
Strong nonlocality with genuine entanglement based on GHZ-like states in multipartite quantum systems
Authors: Yang Ying-Hui , Mi Guang-Wei , Geng Shi-Jiao , Liu Qian-Qian , Zuo Hui-Juan
Published: November 2022

Strong nonlocality with genuine entanglement was first shown by Wang et al using sets of GHZ-like states in tripartite quantum systems (2021 Phys. Rev. A
104, 012 424). However, it is an open problem whether there exists strong nonlocality with genuine entanglement in four or more partite systems. In this paper, we unify two different concepts of strong nonlocality introduced by Halder et al (2019 Phys. Rev. Lett.
122, 040 403) and by Zhang et al (2019 Phys. Rev. A
99, 062108). That is, we use a concept of k-strong nonlocality instead of these two different types of strong nonlocality. A set of orthogonal quantum states is k-strong nonlocal if it is locally irreducible in every k-partition. In fact, the strong nonlocality that is usually said is 2-strong nonlocality. The smaller the k is, the stronger the nonlocality will be. A set of states is k
+-strong nonlocal if the strong nonlocality of this set is stronger than k-strong nonlocality but weaker than (k − 1)-strong nonlocality. Based on these concepts, firstly, we show 2-strong nonlocality with genuine entanglement by some sets of GHZ-like states with weight d in tripartite systems. These sets are not necessarily complete bases. Secondly, we present 2-strong nonlocality with genuine entanglement for systems with four or more parties. These results solve the open problem raised by Wang et al Finally, we construct a set of GHZ-like states with n
+-strong nonlocality in n-partite quantum systems.
Time-resolved ion energy distribution functions during a HiPIMS discharge with cathode voltage reversal
Authors: Jeckell Zachary , Barlaz David E , Houlahan Thomas , Huber Wolfgang , Haehnlein Ian , Jurczyk Brian , Ruzic David N
Published: November 2022

The effect on the ion energy distribution function (IEDF) of plasma produced during a high-power impulse magnetron sputtering (HiPIMS) discharge as the pulse conditions are varied is reported. Pressure was varied from 0.67–2.00 Pa (5–15 mTorr), positive kick pulses up to 200 V tested with a constant 4 μs delay between negative and positive cycles. The results demonstrate that the resulting plasma during the positive cathode voltage reversal is the result of expansion through the largely neutral gas species between the end of the magnetic trap of the target and the workpiece. The plasma potential rises on similar time scale with the evolution of a narrow peak in the IEDF close to the applied bias. The peak of the distribution function remains narrow close to the applied bias irrespective of pulse length, and with only slight pressure dependence. One exception discovered is that the IEDF contains a broad high energy tail early in the kick pulse due to acceleration of ions present beyond the trap from the main pulse separate from the ionization front that follows.
Impact of pressure on the resonant energy and resonant frequency for two barriers Ga1−xAlxAs/GaAs nanostructures
Authors: Elkenany Elkenany B. , Elabsy A M
Published: November 2022

We study the effect of hydrostatic pressure on resonant frequency (ν
1) and its associated lifetime (τ
1), and energy (E1) for electrons tunneling through GaAs-AlGaAs two-barrier nanostructure (TBNS). The effective mass mismatch for well and barrier materials is considered using the effective mass theory. Pressure and the Al content, which mainly affect the barrier height and consequently the TBNS’s, are found to have a significant impact on resonant lifetime, resonant frequency, and resonant energy. The current study shows that the resonance lifetime, resonant frequency, and energy are strongly influenced by the barrier thickness and well width. When comparing the results of this study to the data from the experiment, good agreements are found. The GaAs-AlGaAs TBNS’s electronic devices are controlled mainly by the hydrostatic pressure.
Determination of hot-electron drift velocity in (Be)ZnMgO/ZnO 2DEG channels
Authors: Ardaravičius Linas , Kiprijanovič Oleg , Šermukšnis Emilis , Avrutin Vitaliy , Özgür Ümit , Morkoç Hadis
Published: November 2022

Recent experimental study of electron transport in ZnO/ZnMgO and BeZnMgO/ZnO heterostructures containing two-dimensional electron gas (2DEG) channels of two polarities is reported where electrons are accelerated and become hot by a pulsed electric field. The measurements with electrical pulses ranging from 2 ns to 10 ns in duration ensure the control of self-heating effect. Electron transport in the ZnO 2DEG channels located in ZnO layers at the ZnMgO or BeZnMgO barrier or in ZnO 3DEG channels is treated mainly in terms of drift velocity. The highest values of 1.3 × 107 cm/s at 360 kV/cm, 2.0 × 107 cm/s at 270 kV/cm, and 2.5 × 107 cm/s and 320 kV/cm, respectively, are attained and explained by emphasizing the effect of hot phonons.
Effects of oxygen absorption on the electronic and optical properties of armchair and zigzag Silicon Carbide Nanotubes (SiCNTs)
Authors: Saadu Itas Yahaya , Suleiman Abdussalam Balarabe , Ndikilar Chifu E , Lawal Abdullahi , Razali Razif , Idowu Ismail Ibrahim , Khandaker Mayeen Uddin
Published: November 2022

Investigation of the effects of oxygen absorption on the two types of single walled silicon carbide nanotubes (SWSiCNTs) with different chiral angles were done. Our calculations were performed using density functional theory with quantum ESPRESSO and YAMBO codes. Changes in electrical and optical properties were analyzed after introducing two molecules of oxygen as absorbing gas to both armchair and zigzag nanotubes. Results demonstrated a new future by SWSiCNT in which oxygen absorption significantly closes the band gap which transformed the materials from semiconducting to metallic. This future revealed its potential for application as automobile gas switches for air conditioners. Results from optical calculations revealed that zigzag SiCNT is not optically potential above 20 eV, generally, the (6, 6) SWSiCNT demonstrate higher transmission with and without oxygen absorption in the ultraviolet region. The first absorption peaks appeared within the range of 1 eV to 3.4 eV for all systems, there is higher absorption by the oxygen absorbed (6, 6) SWSiCNT than the oxygen absorbed (6, 0) SWZSiCNT. This demonstrates that armchair form of SWSiCNT absorbs gases more than the zigzag form. The absorption peaks can be seen to fall above 3.5 eV and then rise again up to 10 eV, this behavior justifies the nanotubes potential in automobile day light sensors.
Prospects for constraining the Yukawa gravity with pulsars around Sagittarius A*
Authors: Dong Yiming , Shao Lijing , Hu Zexin , Miao Xueli , Wang Ziming
Published: November 2022

The discovery of radio pulsars (PSRs) around the supermassive black
hole (SMBH) in our Galactic Center (GC), Sagittarius A* (Sgr A*), will have
significant implications for tests of gravity. In this paper, we predict
restrictions on the parameters of the Yukawa gravity by timing a pulsar around
Sgr A* with a variety of orbital parameters. Based on a realistic timing
accuracy of the times of arrival (TOAs), σ
TOA = 100 μs, and
using a number of 960 TOAs in a 20-yr observation, our numerical simulations
show that the PSR-SMBH system will improve current tests of the Yukawa gravity
when the range of the Yukawa interaction varies between 101–104
AU, and it can limit the graviton mass to be mg
≲ 10-24 
eV/c
2.
14.77 MeV neutron-induced nuclear reaction cross sections for zinc, yttrium, and molybdenum targets*
Authors: Ganesapandy T.S. , Bholane G.T. , Patil S.H. , Dahiwale S.S. , Bhoraskar V.N. , Dhole S.D.
Published: November 2022

The cross sections for neutron-induced nuclear reactions on natural zinc, yttrium, and molybdenum targets were measured at a neutron energy of 14.77 ± 0.17 MeV using the activation technique, offline gamma-ray spectrometry, and a detailed covariance analysis. The uncertainty in the statistical model calculations of cross sections for the (n, 2n), (n, p), (n, α), and (n, γ) reactions with natural zinc, yttrium, and molybdenum at neutron energies from 13 to 17 MeV was calculated using the TALYS-1.96 nuclear code. The measured cross sections of the present study were compared with the experimental cross sections reported in the EXFOR database, the cross sections were calculated with the TALYS-1.96 and EMPIRE-3.2.3 nuclear codes and the evaluated nuclear data from the TENDL-2019, JENDL-5, and ENDF/B-VIII.0 libraries.
The effect of non-uniform urban illumination upon pedestrians’ alertness and sense of safety
Authors: Jedon R , Haans A , de Kort Y
Published: November 2022

The influence of urban lighting on the visual tasks of pedestrians are well known and, likewise, studies have explored the relationship between urban lighting and pedestrians’ feelings of safety. But there are other, less investigated, possible effects of light in mesopic situations. Research on street lighting for pedestrians has traditionally focused on minimal required illuminance for various visual performance tasks (e.g., obstacle detection and face recognition). However, it is not only pedestrians’ visual performance that is important for safety, but also their general attentiveness to the environment. Despite this, the psychological concepts related to the individuals’ attention, such as alertness, arousal and anxiety, have not been considered in street lighting research to date even though they too can play an important role in pedestrian’s attention and safety. Since proper metrics for these concepts are needed, we conducted a pilot study to test their sensitivity. We decided for a conceptual replication of a field experiment from 1916 and managed to partly replicate the findings. More importantly, we learned meaningful lessons from this endeavour. Implications for future research are discussed.
Physiological effects of white and coloured LED lighting for elderly people
Authors: Oe Y , Miura Y , Akuzawa Y
Published: November 2022

The aim of this study is to investigate the physiological stress effects of light colour on white and coloured LED lighting in the elderly people. The laboratory experiment was conducted on 19 elderly subjects and analysed using heart rate variability. The results showed that the 2700 K and 6500 K conditions, which significantly decreased HR and significantly increased HF, were considered to be relaxing tendencies. Based on the experimental results of previous studies, comparisons with young age groups showed that there were no differences in tendency according to light colour between age groups, but that the tendency to relax may be weakened in elderly people.
The circadian impact of computer monitors with different color configurations
Authors: Huguet-Ferran A , Kántor D , Hernández S , Garrido B
Published: November 2022

The objective of this study is to find out if it is possible to achieve the circadian levels recommended by different published lighting guidelines using different color configurations in a text editor. By measuring 25 monitors of different sizes, the circadian impact is evaluated at a standard distance using two different parameters: Circadian Stimulus and Melanopic Equivalent Daylight Illuminance. After analyzing the results, we see that during the night Circadian Stimulus is, in most cases, within the recommended range, but the same is not true for Melanopic Equivalent Daylight Illuminance. In addition, the circadian impact of the f.lux software has been analyzed and compared with two different cases of color configurations in a text editor.
The school lighting innovation dilemma
Authors: Karlsson Tove , Kjellander Jonas , Machado Åsa , Strandberg Olle , Götlind Peter , Karlsson Reine
Published: November 2022

This paper presents a qualitative descriptive case study that aims to build awareness about the need for improvement of the indoor environment in classrooms and to exemplify how renewal-oriented processes can be initiated. The study focuses on innovation processes that have resulted in both completely new designs and further spread of innovative solutions. The reason for the need to improve is that too many pupils and students have problems with concentration, relaxation and recuperation. The number of diagnoses such as Autism and ADHD is growing. One factor which significantly influences the pupil’s mental well-being is the daily physical environment. The single aspect which may be improved in reasonable time, at a reasonable cost, is the lighting design of classrooms. An underlying reason for the habit to continue installing insipid uniform static “light-carpets” is the lack of awareness about how lighting affects wellbeing and health. As with innovation in other industries, it is an innovation dilemma that the vast majority of the people who sell and procure classroom lighting tend to prefer the established solutions that they are used to. The article describes how Malmö’s early investment in Human Centric Lighting and the unique indoor environment of the Study hall in the Centre for Economic Sciences at Uppsala University are used as role models for lighting design in classrooms. The case study combines the authors’ own observations and earlier interviews with users. Malmö’s temporal light variation and parts of the Study hall’s lighting design are used in more than 30 classrooms, in Malmö, Stockholm Business School and Iggesund. The article concludes with suggestions on how today’s lighting design knowledge and technology can be combined to provide more advanced adaptations to the varying lighting needs of pupils, students and teachers.
Relationship between photon flow and the perception of light field under simple lighting environments
Authors: Kaira Otori , Komazawa Ken , Schregle Roland , Yoshizawa Nozomu
Published: November 2022

In our previous study we proposed a new method, “photon flow”, to visualise the light propagation in space. Theoretically the photon flow depicts the physically correct light distribution, however, it was yet unclear whether people could correctly read the physical light field in actual spaces by observing the photon flow. Therefore, in this study we verified the relationship between the light field perceived in the real space (visual light field) and the one estimated by observing the photon flow. The experiment was conducted using the method of a white sphere, on which shade represents the light field at that point. We clarified the characteristics of the perceived light field in a simple rectangular space with one spotlight or two. The perceived light field when observing the photon flow was basically similar to the physical light field when there is one spotlight in the space. However, under the more complex scene, the subjects sometimes could not predict the physical light field well when seeing the photon flow. Basically, the perceived light field when observing the photon flow was close to the visual light field than expected. In future work we would like to clarify under which conditions people can estimate the correct physical light field by observing the photon flow and compare the difference between experienced and naïve observers.
Amber is not yet the white knight for sustainable outdoor light
Authors: Radetsky L C
Published: November 2022

Non-white light (NWL), and specifically yellow-orange or amber light sources, are often posed as a solution for environmentally sensitive areas and for astronomical sky glow. Lighting requirements published by various institutions ranging from public advocacy groups to governmental regulators demonstrate little agreement on NWL spectral thresholds and metrics. A recent market and performance analysis of NWL policies and products found that current international guidelines are not aligned, the terminology currently used by the lighting industry is inconsistent, and NWL LED products would likely not meet performance requirements for luminaire efficacy or colour rendition set by existing certification bodies.
Optimizing exterior lighting illuminance and spectrum for human, environmental, and economic factors.
Authors: Simmons S M , Baur S , Gillis W , Burns D , Pickerill H
Published: November 2022

With the recent widespread adoption of LED lighting in outdoor areas, numerous concerns have been raised about the potential for harmful effects on humans, animals, plants, and the night sky. These stem from the high blue light content of some LED bulbs and an incentive to increase lighting levels caused by higher efficiency and lower costs. While new lighting installations are often described as environmentally friendly due to their energy efficiency, factors such as light pollution are often neglected or not given enough weight. This research focuses on optimizing the design of exterior lighting for human, environmental, and economic factors using a multi-criteria decision analysis. Based on data in the literature and survey research, illuminance and spectrum alternatives were scored relative to each other using the analytic hierarchy process and multi-attribute utility theory. The findings of this study support the use of artificial illumination at levels similar to a full moon (0.01 fc) and a warm white spectrum (2700K or 2200K), with amber LED becoming a better choice if its energy efficiency and cost effectiveness improve in the future. This methodology can be used in the future as a framework for lighting design optimization in different settings.
Light and emotions. The importance of context
Authors: León O Y Vara
Published: November 2022

The main objective of this work is to determine if lighting can help triggering emotions in the inhabitants, and if so, if it can be achieved through design. For this, a literature review of several authors, such as Sztulwark, Rose, Chaves, Lozoya and Crilly among others was needed. This was seen through an interdisciplinary approach where several concepts were translated to the lighting design field, built from others, and linked to make them useful for this purpose. The understanding of this concepts will help as a tool to understand the relation between lighting and emotions. Concepts such as context, artifact, use and function will take an important role. Subjects such as communication and the importance of language, as well as the inhabitant’s interpretation of the space and its lighting will be touched. Light will be treated as a material and lighting as an artifact with which the inhabitant has a direct contact. The relation of lighting and emotions will be seen differently than that of a direct action-reaction. It was found that the thoroughly understanding of context was the link between light and emotions that should be understood and worked, although the expected result will not always be successful.
Universal lighting design: Towards sustainable lighting solutions that support function, experience and human diversity
Authors: Nielsen SL , Ryhl C
Published: November 2022

This paper introduces the principle of Universal design into the field of lighting design by pointing to and discussing their shared understandings of human diversities, and how functionality as well as experiencing are equally important aspects of designs. This introduction is initialized by the presentation of a thematic analysis of an ethnographic field study investigating how midwives practice and experience lighting in the delivery room during childbirth. Taking on a phenomenological approach, the analysis showcases how lighting both serves a tool to support functional medical practices, and as a tool to affect sensory experiences in the delivery room. As such, the analysis serves to integrate understandings of lighting having both functional effects and experiential significance, in addition to pointing out diverse and changing sensitivities to lighting. In this regard, the paper aims to initialize further discussions about how the principle of Universal design may serve as a tool to address and support the quality and sustainability of lighting designs, by embracing human practices, experiences, and differences - leaving no one behind.
Application of K-Means Clustering and Calendar View Visualisation for Air Pollution Index Analysis
Authors: Omar Z Ali , Hashim Siti Rahayu Mohd , Sentian Justin , Chin Su Na
Published: November 2022

Two years of diurnal concentration of particulate matter (PM10
) and nitrogen dioxide with the addition of relative humidity measurement, collected from Putrajaya, Malaysia’s ground-based measurement station from January 2014 to December 2015, were analysed. K-means clustering was employed and optimal clusters of four were identified for each year based on the most suggested number of clusters from internal cluster validation measures of the total within sum of square, silhouette index and gap statistics. Each cluster was then profiled where each mean pollutant sub-indices were calculated and the contributing pollutant to the air pollution index (API) was determined by looking at the maximum value from all sub-indices. This mechanism closely follows the Recommended Malaysian Air Quality Guidelines (RMG) for determining API. Particulate matter was found to be the dominant sub-index in all clusters and then paired with the mean relative humidity for visualisation. A calendar view was selected to show the temporal patterns and we observed a consistent cluster profile with the actual mean values of the selected parameters for most months. The calendar view also suggested that overall, the API (based on particulate matter) in 2014 was much better as compared to 2015.
Assessment of Flood Susceptibility Analysis Using Analytical Hierarchy Process (AHP) in Kota Belud Area, Sabah, Malaysia
Authors: Sharir Kamilia , Lai Goh Thian , Simon Norbert , Ern Lee Khai , Talip Mustapha Abd , Roslee Rodeano
Published: November 2022

This study aims to assess the flood susceptibility analysis using a Geographical Information System (GIS) based-heuristic analysis, namely the Analytical Hierarchy Process (AHP) model. Eight relevant physical parameters have been selected, namely, drainage density, drainage proximity, elevation, slope angle, slope curvature, land use, soil type, and topography wetness index. The relative importance of these factors has been compared in the pairwise matrix to gain weight values during the process of the Analytical Hierarchy Process (AHP). The flood susceptibility zones have been mapped according to their weightage value. Finally, the flood susceptibility map was prepared and classified into six classes as very low, low, moderate, high, and very high susceptibility using the natural break classification method. The accuracy of the flood susceptibility model was validated using the Area Under the Curve (AUC) analysis. The AUC for success rate was estimated at 82.13%.7.
Mapping the Groundwater Potential Areas by Using the GIS Method in Kg Samawang, Sandakan, Sabah, Malaysia.
Authors: Isnain Zulherry , Mokthar Hizrahtul Edora
Published: November 2022

This study aims to study the groundwater potential areas around Kg Samawang, Sandakan by using the Geographic Information System (GIS) method. There are few basic maps and data were used in this study, which is geology, drainage, soil type, lineament, topography, satellite images and rainfall distribution data. A total of seven thematic maps were produced including the lineament density map, drainage density map, landuse map, soil type map, rainfall distribution map, lithology map and topographic elevation map by using the ILWIS 3.0 software. All the thematic maps will be given a weightage based on its compensation to groundwater availability before being integrated based on the Hopkins Linear Equation using the Multi-Class Index Overlay model. This process will produce a forecast map of the groundwater potential at the study area. As a result of the forecast map, it is estimated that 40% of the study area has high potential of groundwater while 60% has medium, low and very low potential. It is hoped that this groundwater potential map can be used for the exploration work in the future.
Earthquake Threats in Ranau – From The Sources of Mensaban and Mesilou Fault
Authors: Termizi Ahmad Khairut , Tongkul Felix , Harith Noor Sheena Herayani , Roslee Rodeano
Published: November 2022

Unlike the majority of Malaysia’s other states, Sabah is characterised by frequent seismological activity; on average, an earthquake of moderate magnitude occurs roughly every 20 years, originating primarily from one of two major sources: either a local source or a regional source. Sabah has seen an upsurge in low to moderate seismic activity in recent years as a result of the fault activities. Between 1900 and lately, magnitudes ranging from MW 2.9 to 6.0 were recorded. While big magnitude earthquakes are relatively uncommon, the area has previously been struck by disastrous earthquakes. Fortunately, the region is demarcated by active Quaternary fault networks. As a result, the area’s seismicity is calculated using line sources corresponding to these faults. Two major fault systems are suspected of being the cause of such activity: the Mensaban fault zone and the Mesilou fault zone, as well as several additional nearby faults. This article explains the process for doing a probabilistic seismic hazard analysis (PSHA) while taking into consideration the peak ground acceleration (PGA) on bedrock in the Ranau region for a 10% and 2% chance of exceedance. The PGA estimate values for Ranau are between 0.08g to 0.16g for PGA 10%, while for PGA 2% was between 0.15g to 0.28g. The PGA value is divided into the following five earthquake hazard classes based on a quarterly geostatistical analysis method. These are “very low,” “low,” “medium,” “high,” and “very high” classes. In general, this quarterly classification is a good way to see how much local seismic activity there is, based on the PGA value. Which can be seen in 10% probability, 19.88 percent of the study area was in “very low,” 20.19 percent was low, 19.98 percent medium, and 19.92 percent high class. 2% probability, it was found that 19.74 percent of the total area was very low class, 20.06 percent low class, 19.79 percent middle class, and 19.82 percent high class. Only 20.6 percent of the area was “very high”.
3D Modelling of Rockfall Hazard at Gunung Lang, Ipoh
Authors: Ghani Muhammad Fahmi Abdul , Simon Norbert , Mohamed Tuan Rusli Tuan , Roslee Rodeano
Published: November 2022

Densely populated hillside regions in humid tropical climatic zones are often prone to various types of mass movement. The development in Kinta Valley is no exception from the rapid development and has prompted the opening of new areas approaching slopes. This type of activity ultimately increased the level of rockfall vulnerability in this area. In this research, we conducted an assessment on the hazard level of Gunung Lang and created a 3D hazard model using the CONEFALL software. Aerial photograph, Landsat ETM+ image and DEM data of Gunung Lang were used in this study for lineament tracing and subsequently used to identify rockfall source and generated a 3D model of our study area using a high-resolution DEM. Based on our model, the maximum velocity of rockfall is approximately 36ms-1 and could travel up to 113 m from its source. Therefore, in order to minimize casualty and property damage, regular monitoring of slope failure are needed.
Settlement behaviour of geothermal energy pile under cyclic thermo-axial loads
Authors: Satar M H Mohd , Marto A , Othman B A
Published: November 2022

Geothermal energy pile (GEP) foundation is a new type of sustainable geostructure that can be used as an alternative solution to the energy demand for heating and cooling of built structures. However, due to limited information of this system, the installed piles have generally been over-designed to lower the risk of the system failing. This paper presents the findings of the research carried out to evaluate the performance of laboratory scaled GEP model (model pile) under the effects of the cyclic thermal loads on the settlement behaviour of the model pile with and without the application of axial load. A small-scale model pile of 19 mm diameter and 300 mm length (150 mm embedded length) was used in the experimental work while kaolin was chosen as the model soil. The model soil was compacted at 90% maximum dry density (1.4625 Mg/m3) with optimum moisture content (17%) to obtain ‘firm’ consistency, in a container of 450 mm height and 270 mm diameter. Strain gauges were installed along the pile to monitor the temperature. The ultimate load, Qu of model pile was determined as 480 N. It is found that two cycles of thermal load decreased the settlement; the higher the values, the lower the settlement due to pile expansion and soil heaves. For thermo-axially loaded pile with two cycles of thermal load, the reduction was not significant as the effect of settlement due to axial load had caused much more settlement. For the thermo-axial loads of 50°C-100 N, 17% of the settlement at failure, sf occurred after the application of axial load. When two cycles of thermal load were applied from 29°C to 50°C, the settlement occurred reduced to 16%sf. From this study it can be concluded that the effect of two cycles of cyclic thermal loads from 29°C to 50°C on pile subjected to 21% of Qu in firm clay, is negligible. The pile could function satisfactorily as designed. However, the application of higher axial loads and cycles of thermal load may need to be studied as it could potentially cause hazard to the building due to the excessive pile settlement.
Application of Analytical Hierarchy Process (AHP) for Landslide Hazard Analysis (LHA) in Kota Kinabalu area, Sabah, Malaysia
Authors: Roslee Rodeano , Sharir Kamilia , Lai Goh Thian , Simon Norbert , Ern Lee Khai , Madran Eldawaty , Saidin Ahmad Syazwan
Published: November 2022

A very good Landslide Hazard Analysis (LHA) model was developed using the Analytical Hierarchy Process (AHP) method for the area of Kota Kinabalu, Sabah. The AHP is defined as theory of measurement through pairwise comparisons and relies on the judgements of experts to derive priority scales that measure intangibles in relative terms. The derived priority scales are synthesised by multiplying them by the priority of their parent nodes and adding for all such nodes. Weighted value of different spatial factors from the best models calculated with the AHP method were derived. The results showed that the geology (27% variance), geodynamic features (14% variance), slope conditions (26% variance), hydrology/hydrogeology (14% variance), types of land use (3% variance), and engineering characteristics of soils (8% variance), and rocks (8% variance) play an important role in landslide susceptibility analysis. In terms of Landslide Hazard Map (LHM), the analyses resulted of Kota Kinabalu area suggests that 2.78% of the area can be categorised as Very Low Hazard, 14.14% as Low Hazard, 19.74% as Moderate Hazard, 51.63% as High Hazard, 11.34% as Very High Hazard and 0.37% as Extremely High Hazard. Model accuracy assessment of LHA was performed using consistency ratio (CR) equal to 0.0129 (< 0.1) (acceptable) and 93.50 % accuracy of the validation prediction. Thus, the newly developed method works satisfactory and high reliability; and is applicable to further research development in Kota Kinabalu, Sabah, and potentially to expand with different environmental settings.
Correlation of Dynamic and Static Young’s Modulus for Limestone
Authors: Serasa Ailie Sofyiana , Rafek Abdul Ghani , Harun Wan Salmi Wan , Abdurrahman Muslim , Ern Lee Khai , Huy Nguyen Xuan , Van Xuan Tran , Roslee Rodeano , Zhang Mingwei , Lai Goh Thian
Published: November 2022

The application of rock mechanics in the area of geotechnical engineering is important especially, in describing the strength of rock material for essessing the stability of excavations, foundations and slopes in rock. In this study, the characterization of the rock material was investigated through the Young’s modulus parameter, which describes the relationship between the stress applied to the rock material and the resulting strain. For an elastic and homogeneous solid, the measurement of Young’s modulus can be determined either from the static or dynamic measurements. Numerous studies outline the differences between the Young’s modulus obtained from static and dynamic measurement in the laboratory. Comparatively, the measurement using static methods are more direct and realistic, as it describes the behaviour of rock deformation until failure occurs. The dynamic methods are more versatile and continuous, as they rely solely on the measurement of elastic wave velocities. However, one of the most notable disadvantages of rock material characterization by means of dynamic methods is that it overestimates the failure of rock material when compared to its actual value. With this in mind, the aim of this study is to obtain the measurements of Young’s modulus using both the static and dynamic methods. Based on the comparison made, an empirical equation of Est = 0.9264 (Edy) + 0.4976 with coefficient of determination, R2 of 0.8 is obtained for estimating the static Young’s modulus for limestone. The equation is applicable in situation where static measurement could not be carried out, and also serves as reliable estimation of Young’s modulus from dynamic measurement.
Engineering Geological Assessment at Grandview Heights, Paya Terubong, Pulau Pinang, Malaysia
Authors: Md Shah Nazlin An’Nisa , Rafek Abdul Ghani , Serasa Ailie Sofyiana , Harun Wan Salmi Wan , Abdurrahman Muslim , Ern Lee Khai , Huy Nguyen Xuan , Xuan Tran Van , Roslee Rodeano , Zhang Mingwei , Lai Goh Thian
Published: November 2022

Grandview Heights, Paya Terubong is an old apartment building situated on a coarse-grained biotite granitic bedrock hillside. Paya Terubong is a landslide prone area where various landslides have been reported since 1998. The granitic hill has been disturbed during construction of the apartment. Due to the possibility of future landslides, an engineering geological study was conducted to assess the stability of this rock hill beneath this apartment. The scopes of study included discontinuity surveys, geomechanical characterization of the rock mass and slope stability analysis. Based on the results of discontinuity surveys, four major joints sets-were identified and labelled as J1 (195°/62°), J2 (248°/65°), J3 (304°/63°) and J4 (230°/39°). One (1) potential planar failure J2 (248°/65°) and one (1) potential wedge failure J1-J2 intersection (213°/60°) were identified based on kinematic analysis. Dry rock density was from 2.56 g/cm3to 2.61g/cm3. The water content was from 0.14 % to 0.15% with low porosity values from 0.50% to 0.54%. The point load strength index, Is(50)was 6.63 MPa. The Slope Mass Rating (SMR) for was 64 to 79 and classified as class II with the probability of failure of 0.2.