bluuebunny/crossref_metadata_2025 huggingface dataset:
Operando atomic force microscopy study of electric double-layer transistors based on ionic liquid/rubrene single crystal interfaces
Authors: Morino Yusuke , Yokota Yasuyuki , Bando Ken-ichi , Hara Hisaya , Imanishi Akihito , Takeya Jun , Fukui Ken-ichi
Published: June 2021

We conducted the operando atomic force microscopy (AFM) of ionic liquid (IL)/rubrene single crystal interfaces under the operation of an electric double-layer (EDL)-gated field-effect transistor (FET). We developed a top-side-gated EDL-FET and performed the simultaneous measurement of device characteristics and frequency-modulation AFM in the IL droplet. The AFM images revealed microscopic and macroscopic changes in the rubrene single crystal surface upon carrier injection by applying a gate voltage.
Determination of Tekirdağ (Turkey) wind energy potential and evaluation of selected wind turbines in terms of techno-economic and environmental aspects
Authors: Akan Aytac Perihan , Akan Ahmet Erhan
Published: June 2021

In this study, the wind energy potential of Tekirdağ was investigated obtaining the wind data from meteorology stations located in nine districts of the province and recorded hourly at 10 m altitude between the years of 2014 and 2018. Moreover, monthly average wind and Weibull and Rayleigh probability distributions, as well as hourly wind speeds, were analyzed for each district. Furthermore, monthly dominant wind directions and the ratio of dominant winds to all wind blowing numbers were determined for each district and wind speeds and wind power densities by month were compared. In addition to determination of wind energy potential, four different types of wind turbines which can be installed in the examined regions were assessed in terms of techno-economic and environmental aspects by using RETScreen Expert software. Capacity factors of selected wind turbines, initial installation costs, annual savings incomes, and annual energy amounts were determined by district. The gross greenhouse gas emission amounts that can be prevented from being released into the environment have been determined via the usage of wind turbine. Finally, the most suitable wind turbines for the districts were determined through financial sustainability analysis. Correspondingly, it has been determined that if the Enercon E2-82 wind turbine is installed in the Marmara Ereğlisi district, optimal results will be obtained. It is thought that this study will contribute to the development of the wind energy potential and planning of the wind power plants in the regions showing the similar characteristics with the examined one with regard to wind energy.
Stochastic transformations of multi-rhythmic dynamics and order–chaos transitions in a discrete 2D model
Authors: Tsvetkov Ivan , Bashkirtseva Irina , Ryashko Lev
Published: June 2021

A problem of the analysis of stochastic effects in multirhythmic nonlinear systems is investigated on the basis of the conceptual neuron map-based model proposed by Rulkov. A parameter zone with diverse scenarios of the coexistence of oscillatory regimes, both spiking and bursting, was revealed and studied. Noise-induced transitions between basins of periodic attractors are analyzed parametrically by statistics extracted from numerical simulations and by a theoretical approach using the stochastic sensitivity technique. Chaos–order transformations of dynamics caused by random forcing are discussed.
Reversal of triboelectric charges on sol–gel oxide films annealed at different temperatures
Authors: Zhu Yongqiao , Lin Shiquan , Gao Wenchao , Zhang Miao , Li Dawei , Feng Peizhong , Xu Cheng , Wang Zhong Lin
Published: June 2021

Using Kelvin probe force microscopy, we studied the contact-electrification (CE) induced charge density on the surfaces of organic–inorganic composite oxide films, such as Nb2O5, ZrO2, and HfO2 films, prepared by a sol–gel method and annealed at different temperatures. The results show that positive triboelectric charges on the film surface gradually turn into negative ones with the increase in the annealing temperature. This phenomenon is attributed to the broken valence bonds between organics and organic–inorganic composites in the film at high temperature, which causes oxygen vacancy defects and consequently changes the surface states of the film. A surface states model is established to understand the process of CE, which further confirms that electron transfer is the dominant mechanism of CE. Moreover, it indicates that in addition to oxygen vacancies, there are also many other factors that can influence CE, including but not limited to non-stoichiometric ratios, impurities, and other types of defects. These factors will modify the surface states through changing the potential barrier energy of the bound electrons on the surface and thus impact the amount and even the direction of electron transfer.
Sessile liquid drops damp vibrating structures
Authors: Erfanul Alam MD , Dickerson Andrew K.
Published: June 2021

In this study, we explore the vibration damping characteristics of singular liquid drops of varying viscosity and surface tension resting on a millimetric cantilever. Cantilevers are displaced 0.6 mm at their free end, 6% their length, and allowed to vibrate freely. Such ringdown vibration causes drops to deform, or slosh, which dissipates kinetic energy via viscous dissipation within the drop and through contact line friction. Damping by drop sloshing is dependent on viscosity, surface tension, drop size, and drop location. A solid weight with the same mass as experimental drops is used to compare against the damping imposed by liquids, thereby accounting for other damping sources. Neither the most viscous nor least viscous drops studied imposed the greatest damping on cantilever motion. Instead, drops of intermediate viscosity strike the most effective balance of sloshing and internal dissipative capacity. Very thin cantilevers with sloshing drops express more than one dominant frequency and vibrate erratically, often shifting phase, presenting a challenge for quantification of damping. Finally, we introduce a new dimensionless group aimed at incorporating all salient variables of our cantilever-drop system.
Mapping wave packet bifurcation at a conical intersection in CH3I by attosecond XUV transient absorption spectroscopy
Authors: Chang Kristina F. , Wang Han , Poullain Sonia M. , Prendergast David , Neumark Daniel M. , Leone Stephen R.
Published: June 2021

Extreme ultraviolet (XUV) transient absorption spectroscopy has emerged as a sensitive tool for mapping the real-time structural and electronic evolution of molecules. Here, attosecond XUV transient absorption is used to track dynamics in the A-band of methyl iodide (CH3I). Gaseous CH3I molecules are excited to the A-band by a UV pump (277 nm, ∼20 fs) and probed by attosecond XUV pulses targeting iodine I(4d) core-to-valence transitions. Owing to the excellent temporal resolution of the technique, passage through a conical intersection is mapped through spectral signatures of nonadiabatic wave packet bifurcation observed to occur at 15 ± 4 fs following UV photoexcitation. The observed XUV signatures and time dynamics are in agreement with previous simulations [H. Wang, M. Odelius, and D. Prendergast, J. Chem. Phys. 151, 124106 (2019)]. Due to the short duration of the UV pump pulse, coherent vibrational motion in the CH3I ground state along the C–I stretch mode (538 ± 7 cm−1) launched by resonant impulsive stimulated Raman scattering and dynamics in multiphoton excited states of CH3I are also detected.
Single-molecule-resolution ultrafast near-field optical microscopy via plasmon lifetime extension
Authors: Ovali Rasim Volga , Sahin Ramazan , Bek Alpan , Tasgin Mehmet Emre
Published: June 2021

Metal nanostructures support plasmon oscillations on their surfaces, which normally decay very quickly. Nevertheless, the lifetime of these oscillations can be extended near a longer lifetime particle, e.g., a molecule. We utilize this phenomenon for ultrahigh (single-molecule) resolution ultrafast apertureless (scattering) applications. We demonstrate the phenomenon with the numerical solutions of 3D Maxwell equations. We use a nm-sized quantum emitter (QE) for the long lifetime particle. We place the QE at the apex of a metal-coated atomic force microscope tip. We illuminate the tip with a femtosecond laser. The near-field on the metal apex decays quickly. After some time, one receives the scattering signal only from the vicinity of the QE. Thus, the resolution becomes single-QE size. We propose the use of a stress-induced defect center in a 2D material as the QE. The tip indentation of the 2D material, transferred to the tip, originates a defect center located right at the sharpest point of the tip, which is exactly at its apex. Our method can equally be facilitated for single-molecule-size chemical manipulation.
Response of broilers to dietary balanced protein. 2. Determining the optimum economic level of protein
Authors: Azevedo Jefferson Moraes , de Paula Reis Matheus , Gous Robert M. , Dorigam Juliano César de Paula , Lizana Rony Riveros , Sakomura Nilva Kazue
Published: June 2021

Context Tables of nutrient requirements assist nutritionists to formulate acceptable feeds for broilers but do not consider the objective of a business, namely, to maximise economic returns. Aims The objective of the present study was to demonstrate that the optimum economic level of balanced protein is not static, but varies according to economic conditions. Methods Responses of male and female broilers, reported in a companion paper, were used to calculate feed intake and weights of body, carcass, breast, leg and wing at 28, 42 and 56 days of age as functions of dietary balanced protein. Cost of feeding and revenue generated for live, dressed, and further-processed birds were calculated, from which the margin over feeding cost was generated separately for males and females at three ages and three revenue-generating scenarios. Key results Using baseline values for the cost of protein-containing ingredients and revenue for birds sold live, dressed or further-processed, the dietary protein content that maximised margin over feed cost was always higher for males than for females, and for birds sold further-processed than for those sold dressed or live. Using digestible lysine as the reference amino acid, the optimum in the starter period for males sold live, dressed and further processed was 12.6, 13.3 and 14.2 g lysine/kg respectively. For females, the equivalent values were 11.9, 12.6 and 13.3 g/kg respectively. Where the cost of protein-containing ingredients was increased by 25% or revenue generated from the sale of product was reduced by 25%, the optimum economic level of dietary protein decreased compared with the baseline value. The opposite pertained when ingredient costs decreased, or revenues increased by 25%. Conclusions These results demonstrated the extent to which economic factors influence the optimum economic level of dietary balanced protein to be fed to broilers. Implications We have demonstrated that the response of broilers to dietary balanced protein may be used to maximise economic returns of a broiler enterprise under different scenarios.
Changes in colour during leaf development of
Authors: dos Santos Gabriel Felisberto , Kuster Vinícius Coelho , de Melo Silva Ana Flávia , Faria Ana Paula , Moreira Ana Silvia Franco Pinheiro
Published: June 2021

Leaf development is affected by different amounts of light, leading to structural and physiological gradients. Young leaves are normally more sensitive to high light levels, which may trigger different strategies for light protection. On this basis, the objective of the current study was to determine strategies used by young (1st node, red), in transition (2nd node, starting to become green, and 4th node, almost all green) and mature (6th node, green) leaves of Eugenia uniflora L. (Myrtaceae) to deal with light. Young leaves showed less structural protection from light, which improved after the 2nd node. The reddish colour of young E. uniflora leaves is mainly due the greater production of photoprotective pigments, mainly anthocyanins, although the chlorophyll/carotenoid ratio showed some contribution by the carotenoids. Reactive oxygen species were homogeneously distributed in the young leaves, turning to malondialdehyde only in older leaves. The lower structural protection from light and physiological immaturity of young E. uniflora leaves lead to photoinhibition and reduced quantum yield during at times of highest light intensity of the day, causing lower efficiency in electron transport. The E. uniflora case clarifies the occurrence of different defence strategies against light exposure according to leaf developmental stages.
Estimating genetic nurture with summary statistics of multigenerational genome-wide association studies
Authors: Wu Yuchang , Zhong Xiaoyuan , Lin Yunong , Zhao Zijie , Chen Jiawen , Zheng Boyan , Li James J. , Fletcher Jason M. , Lu Qiongshi
Published: June 2021

Significance

It has been shown that human genomes can affect phenotype both directly (through inherited genetic variants) and indirectly (through parents and the family environment they create). Due to the correlation between parental and offspring genotypes, a standard genome-wide association study (GWAS) captures both the direct and indirect genetic effects. In this study, we introduce a statistical framework named DONUTS to estimate direct and indirect effects using summary statistics from GWAS conducted on own and offspring phenotypes. It requires only GWAS summary statistics as input, allows differential paternal and maternal effects, and accounts for sample overlap and assortative mating. DONUTS provides deeper etiological insights for complex traits and has practical guidance on future study designs.
Reduced microbial stability in the active layer is associated with carbon loss under alpine permafrost degradation
Authors: Wu Ming-Hui , Chen Sheng-Yun , Chen Jian-Wei , Xue Kai , Chen Shi-Long , Wang Xiao-Ming , Chen Tuo , Kang Shi-Chang , Rui Jun-Peng , Thies Janice E. , Bardgett Richard D. , Wang Yan-Fen
Published: June 2021

Significance

Permafrost degradation may induce soil carbon (C) loss, critical for global C cycling, and be mediated by microbes. Despite larger C stored within the active layer of permafrost regions, which are more affected by warming, and the critical roles of Qinghai–Tibet Plateau in global C cycling, most previous studies focused on the permafrost layer and in high-latitude areas. Here, we demonstrate in situ that permafrost degradation alters the diversity and potentially decreases the stability of active layer microbial communities. Additionally, these changes are associated with soil C loss and potentially a positive C feedback. This study provides insights into microbial-mediated mechanisms responsible for C loss within the active layer in degraded permafrost, aiding in the modeling of C emission under future scenarios.
Paradoxical stabilization of relative position in moving frames
Authors: Özkan Mert , Anstis Stuart , ’t Hart Bernard M. , Wexler Mark , Cavanagh Patrick
Published: June 2021

Significance

Every eye movement drags the visual scene over our retinas and yet nothing appears to move. We now report a small-scale version of this visual stability with a square frame moving on a monitor in a well-lit room. Probes flashed before and after the frame’s motion are also stabilized in the frame’s coordinates—as if the frame were stationary—shifting perceived locations by up to half the screen’s width from their physical locations. Paradoxically, with these small frames, this ∼100% stabilization occurs despite visible frame motion. Unlike motion-induced position shifts, frame-induced shifts are independent of speed and depend instead on the distance the frame travels. This powerful discounting of motion may reveal a critical component of visual stability.
Vibrational relaxation dynamics in layered perovskite quantum wells
Authors: Quan Li Na , Park Yoonjae , Guo Peijun , Gao Mengyu , Jin Jianbo , Huang Jianmei , Copper Jason K. , Schwartzberg Adam , Schaller Richard , Limmer David T. , Yang Peidong
Published: June 2021

Significance

Halide perovskites, especially layered perovskites, offer a number of advantages to creating bright and efficient light-emitting devices and other optoelectronic applications. The organic–inorganic hybrid layered perovskite features complex lattice dynamics due to the ionic character of the crystal and the softness arising from noncovalent bonds between molecular moieties and the inorganic network. Especially, the packing geometry of the organic barriers leads to a structural deformation of inorganic octahedral, which strongly affects the properties that are crucial for device applications. In this work, we use high-resolution resonant impulsive stimulated Raman spectroscopy of a variety of ligand substitutions in layered perovskites. We find the composition of organic ligands can substantially change the dephasing rate of optical phonons and their temperature dependence, due to varying degrees of anharmonicity in the lattice and dynamic structural disorder.
Inflammation as a regulator of hematopoietic stem cell function in disease, aging, and clonal selection
Authors: Caiado Francisco , Pietras Eric M. , Manz Markus G.
Published: June 2021

Inflammation is an evolutionarily selected defense response to infection or tissue damage that involves activation and consumption of immune cells in order to reestablish and maintain organismal integrity. In this process, hematopoietic stem cells (HSCs) are themselves exposed to inflammatory cues and via proliferation and differentiation, replace mature immune cells in a demand-adapted fashion. Here, we review how major sources of systemic inflammation act on and subsequently shape HSC fate and function. We highlight how lifelong inflammatory exposure contributes to HSC inflamm-aging and selection of premalignant HSC clones. Finally, we explore emerging areas of interest and open questions remaining in the field.
Innate immune pathways and inflammation in hematopoietic aging, clonal hematopoiesis, and MDS
Authors: Trowbridge Jennifer J. , Starczynowski Daniel T.
Published: June 2021

With a growing aged population, there is an imminent need to develop new therapeutic strategies to ameliorate disorders of hematopoietic aging, including clonal hematopoiesis and myelodysplastic syndrome (MDS). Cell-intrinsic dysregulation of innate immune- and inflammatory-related pathways as well as systemic inflammation have been implicated in hematopoietic defects associated with aging, clonal hematopoiesis, and MDS. Here, we review and discuss the role of dysregulated innate immune and inflammatory signaling that contribute to the competitive advantage and clonal dominance of preleukemic and MDS-derived hematopoietic cells. We also propose how emerging concepts will further reveal critical biology and novel therapeutic opportunities.
Application of fluorescent dextrans to the brain surface under constant pressure reveals AQP4-independent solute uptake
Authors: Smith Alex J. , Akdemir Gokhan , Wadhwa Meetu , Song Dan , Verkman Alan S.
Published: June 2021

Extracellular solutes in the central nervous system are exchanged between the interstitial fluid, the perivascular compartment, and the cerebrospinal fluid (CSF). The “glymphatic” mechanism proposes that the astrocyte water channel aquaporin-4 (AQP4) is a major determinant of solute transport between the CSF and the interstitial space; however, this is controversial in part because of wide variance in experimental data on interstitial uptake of cisternally injected solutes. Here, we investigated the determinants of solute uptake in brain parenchyma following cisternal injection and reexamined the role of AQP4 using a novel constant-pressure method. In mice, increased cisternal injection rate, which modestly increased intracranial pressure, remarkably increased solute dispersion in the subarachnoid space and uptake in the cortical perivascular compartment. To investigate the role of AQP4 in the absence of confounding variations in pressure and CSF solute concentration over time and space, solutes were applied directly onto the brain surface after durotomy under constant external pressure. Pressure elevation increased solute penetration into the perivascular compartment but had little effect on parenchymal solute uptake. Solute penetration and uptake did not differ significantly between wild-type and AQP4 knockout mice. Our results offer an explanation for the variability in cisternal injection studies and indicate AQP4-independent solute transfer from the CSF to the interstitial space in mouse brain.
Characterization of angularly resolved EUV emission from 2-µm-wavelength laser-driven Sn plasmas using preformed liquid disk targets
Authors: Schupp R , Behnke L , Bouza Z , Mazzotta Z , Mostafa Y , Lassise A , Poirier L , Sheil J , Bayraktar M , Ubachs W , Hoekstra R , Versolato O O
Published: June 2021

The emission properties of tin plasmas, produced by the irradiation of preformed liquid tin targets by several-ns-long 2 µm-wavelength laser pulses, are studied in the extreme ultraviolet (EUV) regime. In a two-pulse scheme, a pre-pulse laser is first used to deform tin microdroplets into thin, extended disks before the main (2 µm) pulse creates the EUV-emitting plasma. Irradiating 30- to 300 µm-diameter targets with 2 µm laser pulses, we find that the efficiency in creating EUV light around 13.5 nm follows the fraction of laser light that overlaps with the target. Next, the effects of a change in 2 µm drive laser intensity (0.6–1.8 × 1011 W cm−2) and pulse duration (3.7–7.4 ns) are studied. It is found that the angular dependence of the emission of light within a 2% bandwidth around 13.5 nm and within the backward 2π hemisphere around the incoming laser beam is almost independent of intensity and duration of the 2 µm drive laser. With increasing target diameter, the emission in this 2% bandwidth becomes increasingly anisotropic, with a greater fraction of light being emitted into the hemisphere of the incoming laser beam. For direct comparison, a similar set of experiments is performed with a 1 µm-wavelength drive laser. Emission spectra, recorded in a 5.5–25.5 nm wavelength range, show significant self-absorption of light around 13.5 nm in the 1 µm case, while in the 2 µm case only an opacity-related broadening of the spectral feature at 13.5 nm is observed. This work demonstrates the enhanced capabilities and performance of 2 µm-driven plasmas produced from disk targets when compared to 1 µm-driven plasmas, providing strong motivation for the use of 2 µm lasers as drive lasers in future high-power sources of EUV light.
On the formation of antihydrogen beams using travelling optical lattices
Authors: Madsen N , Charlton M
Published: June 2021

The production of beams of antihydrogen atoms using the dipole force provided by a travelling optical lattice to accelerate a sample of the anti-atoms held in a magnetic gradient atom trap is investigated. By considering current and near-future antihydrogen trapping capabilities we find that useful fluxes of the anti-atoms can be achieved with directional properties that can be manipulated using laser parameters such as pulse duration and frequency chirp rate. Applications of the beams are briefly discussed.
Decoupling of asymmetric dark matter during an early matter dominated era
Authors: Chanda Prolay , Unwin James
Published: June 2021

In models of Asymmetric Dark Matter (ADM) the relic density is set by a particle asymmetry in an analogous manner to the baryons. Here we explore the scenario in which ADM decouples from the Standard Model thermal bath during an early period of matter domination. We first present a model independent analysis for a generic ADM candidate with s-wave annihilation cross section with fairly general assumptions regarding the origin of the early matter dominated period. We contrast our results to those from conventional ADM models which assume radiation domination during decoupling. Subsequently, we examine an explicit example of this scenario in the context of an elegant SO(10) implementation of ADM in which the matter dominated era is due to a long lived heavy right-handed neutrino. In the concluding remarks we discuss the prospects for superheavy ADM in this setting.
Online detection of movement during natural and self-initiated reach-and-grasp actions from EEG signals
Authors: Pereira Joana , Kobler Reinmar , Ofner Patrick , Schwarz Andreas , Müller-Putz Gernot R
Published: June 2021

Movement intention detection using electroencephalography (EEG) is a challenging but essential component of brain–computer interfaces (BCIs) for people with motor disabilities. Objective. The goal of this study is to develop a new experimental paradigm to perform asynchronous online detection of movement based on low-frequency time-domain EEG features, concretely on movement-related cortical potentials. The paradigm must be easily transferable to people without any residual upper-limb movement function and the BCI must be independent of upper-limb movement onset measurements and external cues. Approach. In a study with non-disabled participants, we evaluated a novel BCI paradigm to detect self-initiated reach-and-grasp movements. Two experimental conditions were involved. In one condition, participants performed reach-and-grasp movements to a target and simultaneously shifted their gaze towards it. In a control condition, participants solely shifted their gaze towards the target (oculomotor task). The participants freely decided when to initiate the tasks. After eye artefact correction, the EEG signals were time-locked to the saccade onset and the resulting amplitude features were exploited on a hierarchical classification approach to detect movement asynchronously. Main results. With regards to BCI performance, 54.1% (14.4% SD) of the movements were correctly identified, and all participants achieved a performance above chance-level (around 12%). An average of 21.5% (14.1% SD) of the oculomotor tasks were falsely detected as upper-limb movement. In an additional rest condition, 1.7 (1.6 SD) false positives per minute were measured. Through source imaging, movement information was mapped to sensorimotor, posterior parietal and occipital areas. Significance. We present a novel approach for movement detection using EEG signals which does not rely on upper-limb movement onset measurements or on the presentation of external cues. The participants’ behaviour closely matches the natural behaviour during goal-directed reach-and-grasp movements, which also constitutes an advantage with respect to current BCI protocols.
Retraction: The improvement of model predictive control based on three-level three phase inverter (J. Phys.: Conf. Ser.
1601 042032)
Authors: Liu Feng , Dai Jun
Published: June 2021

This article has been retracted at the request of the authors, who have identified errors in the paper which affect the scientific validity of the work. The authors specifically state "the coefficient of i1T1 should be (1-2k) instead of (2k-1) in the paper. This error is likely to cause conclusions to violate the actual situation."

The authors apologise to the readers, conference organisers and IOP Publishing for these errors.

Retraction published: 15 June 2021
Cross section of the
13C(α,n)16O reaction at low energies
Authors: Ciani G. F. , Csedreki L. , Balibrea-Correa J. , Best A.
Published: June 2021

The
13C(α, n)16O reaction is the main neutron source for the s-process in low mass AGB stars. Although several direct measurements have been performed, no dataset reaches the Gamow window (140-250 keV) due to the the exponential drop of the cross section σ(E) with decreasing energy. The reaction rate becomes so low that the strong cosmic background would become predominant.

In order to measure the
13C(α, n)16O cross section at low energies, a double effort has been performed, namely to suppress the background in the setup and to keep under control the target modification under an intense stable beam provided by the LUNA accelerator (100-200 µA). These measurements were carried out in deep underground laboratories of Laboratori Nazionali del Gran Sasso (LNGS) in the framework of the LUNA experiment. Preliminary results are reported in this contribution.
Analysis and impact of digital modulation techniques on LTE over fibre for 5G systems applications.
Authors: Ojo J S , Dare F O
Published: June 2021

The impact of digital modulation techniques used in Long Term Evolution (LTE) when applied to radio over fibre for fifth-generation systems has been analysed and evaluated in this paper. The analyses are based on the measured BER and the observed eye-diagram with quality factors for the different modulation techniques such as QPSK, 16 QAM, 64 QAM, and 256 QAM. A fibre length between 5 km and 100 km is adopted to showcase the best configuration at a particular length that can support 5G systems. Huge bandwidth and low latency with high spectral efficiency are needed to accommodate 5G applications in areas of critical surgery, home automation, smart transportation, security, and smart cities via IoT among others. Recent researches are focusing on a synergy between the wireless systems and optical network systems to enhance the transmission of RF signals from a central location to a separate unit of the radio element known as the remote radio head (radio over fibre). This technology merges the optical networks and microwaves to provide a possible solution to increase channel capacity, mobility, and reduced the cost of the access network for customers’ comfort. The whole system link is simulated using a commercial optical simulator Optisystem 17.
Basin-wide water demand estimation using RGB color detection of built-up area from satellite imagery
Authors: Lee W K , Syed Yusoff S I
Published: June 2021

The unavailability of as-built drawings and population data in primarily rural east central Java, Indonesia, presents a challenge to effectively estimate the total demand of a proposed large-scale retrofit water supply scheme. A simple RGB color detection method is employed to analyse satellite imageries extracted from Google Earth. The applicable range of RGB spectrum for typical rooftops is ascertained based on image inspection and the candidate areas identified are filtered, smoothened and manually cleaned-up to produce the total built-up area by pixel calibration. Water demand is then estimated based on assumed population equivalent per standard residential unit and consumption rate. The preliminary estimate is further corroborated with the most recent census and population growth rate. Result show that the approach taken is a cost-effective and efficient way for large-scale areal approximation.
Estimation of cloud attenuation over some coastal cities for satellite space links in South Africa
Authors: Olurotimi E O
Published: June 2021

One of the vital constraints on satellite space link systems operating at higher frequencies is attenuation due to clouds. This paper presents a 5-year estimation of cloud attenuation in the millimeter-wave propagation over two coastal cities in the Republic of South Africa. The results show that some salient features of clouds observed were monthly and location dependent. The observed average cloud value ranges between 16% and 55.6%, the relative humidity recorded between 65.4% and 84.2%, while the rainfall amount is between 5.43 and 79.66 mm over the study locations. The specific attenuation coefficient and cloud attenuation increases as the frequency increases over the studied locations. Furthermore, about 1 dB and above was observed at frequencies from 60 GHz and above. The study reveals the impact of liquid water content (LWC) in the clouds, which has a more significant effect on radio signals. The differences in the attenuation observed may be due to the impact of LWC and other salient features observed over the locations.
The Relationship between Ball Speed and Shooting Accuracy during Field Hockey Hit
Authors: Manaf Muhammad Irhami Abdul , Mohamad Nur Ikhwan , Malek Nor Fazila Abd , Jahizi Ahmad Aqil Mohamad , Nadzalan Ali Md
Published: June 2021

There are numerous studies conducted on fundamental skills in field hockey especially drag flick but there is lack of study did on hit or drive skill despite of there were so many beginner and amateur players that required enhancement in this crucial skill. The purpose of this study was to investigate the relationship between ball speed, accuracy, and years of involvement during field hockey hit performance among student recreational players. Fourteen male players were recruited among university students (n=14; Weight = 65.71 ± 7.85 kg, Height = 168.29 ± 3.97 cm; BMI = 23.14 ± 2.41 kg/m2). The participants were required to perform a best single hit skill to determine their ball speed through Kinovea software and the accuracy by the designated score. Then, the data has been analysed through Pearson correlation using the Statistical Package for Social Sciences (SPSS) 21. The Pearson correlation indicated that there is no significant difference for between ball speed and accuracy (r = .024, p = 936) and years of involvement and accuracy (r = .250. p = 389). However, there was a strong and positive correlation between years of involvement and ball speed (r = .672, p =.008). Findings of the current study suggest that the ball speed and accuracy can be increase both at the same time vice versa during hit skill and years of involvement in this sports can be a contributing factor in skill performance.
Comparison of Muscle Activation between Traditional, Clap and Power Push Up Among Trained Men
Authors: Nadzalan Ali Md , Mohd Latif Azane Azran , Hamdan Ahmad Syahir , Yen Lee Ernie Leong , Tan Kevin , Mohamad Jahizi Ahmad Aqil , Pratama Rivan Sagitha
Published: June 2021

This study was conducted to compare the muscle activation during traditional, clap and power push up among trained men. A total of thirty trained men that are physically active and have at least one year experienced in fitness training and having good techniques in push up exercises were recruited as study participants. Participants were required to perform all three types of push up in a randomised order to avoid bias in the exercise sequence. Electromyogram was used to detect the muscle activites of pectoralis major, triceps brachii and anterior deltoids. Muscle activation was reported as percentage of the maximum voluntary contraction value. The results showed that the muscle activation was highest during the clap push up followed by the power push up and traditional push up. As a conclusion, increasing the difficulty by applying plyometric technique during push up give a significant impact in terms of muscle activation in which is believed to be affect the muscle strength and size in long term.
Relationship between Squat Mobility with Snatch and Clean & Jerk Technique
Authors: Mohamad Nur Ikhwan , Alali Ahmad Alhussin , Malek Nor Fazila Abd , Nadzalan Ali Md
Published: June 2021

The purpose of this study is to find if the mobility of the body effect on the Olympic lifting technique performing. Participants of this study involved 22 males and 22 females students Faculty of Sport Science and Coaching aged 20-24 years old. Participants were instructed to perform 3 repetitions of overhead squat mobility performance first, using only their own bodyweight without any equipment at all. Finished with that, participants were then instructed to performed 3 repetitions of snatch technical performance and proceed to the clean and jerk technical performance using the custom-made plastic pipe bar or 20-kg Olympic bar without plate. Result showed that all students had ‘Good” quality of mobility required for the technical performance of snatch, clean and jerk, however practical test indicated a mastery or quality of the technical performance for the snatch was just considered as ‘Fair’ for the male, with the female students scores dip into the ‘Poor’ level of performance. For both genders, all students have a poor technical performance quality for the clean and jerk exercise.
Investigation of Suspended Sediment Samplers: A Review
Authors: Ansari E , Akhtar M N , Bakar E A , Hawary A F , Alhady S S N
Published: June 2021

The flow of rivers and streams carries many particles like sand and silts due to erosion phenomenon which are commonly termed as sediments. Sediments transported along the water flow distributes into either bed load or suspended load. The heavier particles settle down the river bed and form the bed load. While the lighter particles gets suspended along the surface of the water body and are termed as suspended load. The change in sediment concentration affects the hydromorphology of rivers to a great extent. The current study focusses on the measurement of the suspended sediment and reviews the various suspended sediment samplers based on different technical parameters such as working principle, accuracy and specifications. Different mechanical samplers such as bottle and trap samplers, pump samplers; electronic samplers such as Acoustic backscatter profiling sensors (ABS), etc. and optical samplers such as Optical backscatter point sensor (OBS), Optical Laser diffraction point sensors (LISST) and many more sensors such as impact sensors, nuclear sensors and conductivity sensors are reported and compared in this review.
Teaching Approach using Microsoft Teams: Case Study on Satisfaction versus Barriers in Online Learning Environment
Authors: Ismail Sarerusaenye , Ismail Shahrinaz
Published: June 2021

The current pandemic due to Covid-19 has affected most industries including education services. All universities in Malaysia were instructed to close during the first Movement Control Order (MCO), however the classes were still going on in some of the universities. Most of the student’s learning time during this period has been added to the time that most of them already spent at home since the semester began without explicit face-to-face (FTF) instruction from lecturers. Meanwhile, lecturers are scrambling to adapt with the new situation and prepare suitable contents for an online learning platform. This study investigates the problems and challenges that emerged when using online platform, focusing on Microsoft Teams application (Microsoft Teams), and proposes a model of online teaching for theoretical courses in university. The constructive online survey is chosen as the methodology and data collected from 154 undergraduate students are analysed using a technique of quantitative analysis. The results are discussed and at the end, this study proposes a teaching online course via Microsoft Teams application model that is suitable based on successful outputs.
Reliability Analysis on Water Pumps in Water Supply System in Johor
Authors: Alshaari A H , Nor M E
Published: June 2021

The utilization of water pumps in supplying water facilities to consumer should be given priority in terms of operating performance and availability. In light of that, reliability assessments on water pumps were carried out through Mean Time Between Failure (MTBF), Mean Time to Repair (MTTR) and availability. Then, the water pumps’ brands were compared using Mean Cumulative Function (MCF) plot and suggestion strategies through Failure Modes, Effects and Criticality Analysis (FMECA) approach were conducted. There were two types of old and new water pumps which are raw water pump (RWP) and treated water pump (TWP). The name of the brand of old and new RWP and TWP are Brand A, Brand C, and Brand B. Throughout the study, the finding shows that old RWP and new TWP are the most reliable water pumps based on the computation. Besides, Brand A and Brand C were the best brands among others water pumps’ brand by comparing the performance using the MCF plot. Lastly, the suitable strategies suggested to be focused on predictive maintenance, preventive maintenance and corrective maintenance in handling the maintenance.
STRUCTURAL AND ELECTRONIC PROPERTIES OF NBPT INHIBITOR ATTACHED TO UREASE
Authors: Azman Muhammad Harith Daniel , Sin Ang Lee , Zuber Sharifah Zati Hanani Syed , Yaakob Mohd Hafiz , Ghani Zaidi Ab
Published: June 2021

In this study, the structural and electronic properties of the N-(n-Butyl) Thiophosphoric Triamide (NBPT) inhibitor, in the form of monoamidothiophosphoric acid (MATP), as attached to urease enzyme, has been investigated. These include the electron density, molecular orbitals involved in the interactions, and the whole system’s charge distributions. The difference between the interaction of urease-NBPT and urease-urea was conducted throughout this study. This comparison was crucial to prove the NBPT inhibitor’s mechanism to slow down urea’s hydrolysis in the soil solution. The quantum mechanical calculations were performed at the level theory B3LYP/6-31G(d,p). The urease-NBPT complex has higher interaction energy than the urease-urea complex, in which the interaction energy is –1.6787 eV. The urease-NBPT complex has a lower molecular electronic energy gap than the urease-urea complex, at 0.9527 eV. The graphical representation of HOMO, LUMO, and electrostatic potential maps indicates that the NBPT inhibitor can create favourable interaction with the atoms at urease’s active site.
DriverSeekers - A mobile designated driver services system
Authors: Xiin Loh Giin , Shibghatullah Abdul Samad , Jalil Abdurrahman , Wahab Mohd Helmy Abd
Published: June 2021

The intention of this project is to determine the limitations of the current market needs where the road injuries and fatalities are a growing concern in Malaysia. Without any hesitation, the resident’s driving pattern and behavior are highly correlated. Hence, the objective of this study is to develop a prototype mobile application DriverSeekers for pairing drivers with users who do not wish or do not have the ability to drive their own vehicles. An in-depth review of other research and literature is conducted to understand the benefits, impact, and features that similar programs are providing. Further, a qualitative survey has been given out to understand the potential users of the application and the feasibility of the proposed system which includes the user’s concern, preferences, and expectations, whereas the respondents are 10 students and 10 people who are employed. Once the data has been gathered and analyzed, the features of the application are build based on the collected data where the application is trying to meet the user requirement. Afterward, there are four testing phases consist of unit testing, integration testing, system testing, and user acceptance testing which are conducted to assure the system features and functions achieve what the users expect. Further, a UAT is conducted to ensure the users are joyed with the result which meets their requirements and expectation. Thus, the objectives of this study were all successfully fulfilled.
4 × 1 Array Antenna with Staging Transmission Line for Vehicle 5G Application
Authors: Ibrahim Muhamad Shahiren , Jamlos Mohd Aminudin , Mustafa Wan Azani , Idrus Syed Zulkarnain Syed
Published: June 2021

This project implemented the role of 5G technologies for vehicle application. 5G connectivity will give added value to a vehicle, to be able to connect to the networks and also talk to each other without any interference in very low latency. Implementing such kind of this technology will leverage disruptive new applications that will allow to improve driving efficiency and enhance road safety. With the increasing demand for mobile traffic and the delay and security of VANET based on IEEE 802.11p, the key technology of the fifth-generation mobile communication (5G) is combined with the functional characteristics of vehicle networking. And analyzes the application of D2D technology, cognitive radio to improve vehicle communication delay, flexibility, spectrum utilization efficiency and 5G technology in automatic driving. Finally, the potential application of 5G vehicular network is pointed out. This project used microstrip antenna because it has several advantages that did not feature on conventional microwave antenna such as light weight, low volume and thin profile configurations, which can be made conformal. The fabrication process might not cost the budget and mass production is also possible in a period. This research work is focusing on design, simulate, fabricate and analyze a 5G wireless antenna that operates at 26 GHz to 28 GHz by using Rogers RT/Duroid 5880, where this range of frequencies is one of the standard frequencies of the 5G communication. The development of wireless device prototype is also focused in this project as it will be install on a vehicle to enable 5G. This project consist of three major parts which are calculation, simulation and hardware design. Computer Simulation Technology (CST) microwave studio software used to simulate the designed antenna, it prompt the optimization of the antenna designed to achieved desired result before proceed with fabrication. The comparison between theoretical result and practical result was made to analyze margin error and trace the probable cause of the error. The measure of the antenna performance (basic antenna parameter) between array antenna and single patch antenna also studied in this project to conclude the most compatible antenna for vehicle application. 40 GHz Vector Network Analyzer (VNA) had been used to measure the fabricated antenna.
A Simple Blood Vessel Detection on Retinal Image Using Image Processing Technique
Authors: Nursyafiqah Siti , Mustafa Wan Azani , Idrus Syed Zulkarnain Syed , Jamlos Mohd Aminudin
Published: June 2021

Detection of blood vessel plays an important stage in different medical areas, such as ophthalmology, oncology, neurosurgery and laryngology. The significance of the vessel analysis was helped by the continuous overview in clinical studies of new medical technologies intended for improving the visualization of vessels. In this paper, a new blood vessel detection using a simple method of image processing was proposed. The main objective is to propose new method in order to detect the blood vessel on the degraded retinal input image (DRIVE dataset). A few Image Quality Assessment (IQA) such as sensitivity, specificity and accuracy was obtained to prove the effectiveness of detection methods.
Centroidal-Polygon: Solving First Order Ordinary Differential Equation using Centroidal mean to improve Euler Method
Authors: Nur Shahirah Z , Nooraida S , Wan Farah Hanan W A , Suzanna R A , Iliana M A
Published: June 2021

Euler method is one of the oldest and simplest numerical techniques to solve mathematical problems. However, the Euler method lacks accuracy compared to other methods such as the Runge-Kutta and the Adam Bashforth. This research proposed a new scheme by enhancing the Euler method using centroidal mean, i.e. combining the Euler method and the mean concept. In this research, the proposed scheme would be used to improve the accuracy of the first order Ordinary Differential Equation (ODE). The enhanced Euler method was used based on the improved Euler method, which is a midpoint method. To analyse the accuracy of the proposed scheme and the existing schemes, SCILAB 6.0 software was used to compare the results of different step sizes. This research compared the proposed scheme with the Polygon scheme by Zul Zamri and the Harmonic-Polygon scheme by Nurhafizah. By using Centroidal-Polygon as the proposed scheme, more accurate results were yielded. However, the scheme was limited to some of the linear and non-linear equations only.