Low Average Speed Research Articles

Understanding pedestrian crowd dynamics on ramps: An empirical study triggered by Seoul Halloween crowd crush

Pedestrian safety on ramps demands greater attention compared to flat surfaces, as exemplified by a tragic crowd crush accident that claimed the lives of over 150 individuals on a densely populated ramp in South Korea in 2022. Understanding the dynamics of pedestrian movement on ramps is crucial for effectively managing mass events and daily pedestrian transportation. This paper presents an empirical study investigating bidirectional pedestrian flows on a simulated ramp with varying inclinations. Flow ratios, indicating the group size of major and minor flows in both directions, were examined. Results show that bidirectional pedestrian streams exhibit self-organizing behavior, characterized by the emergence of distinct lane formation phenomenon in both level and ramp walking scenarios. The shortest overall time required for pedestrians to exit the ramp was observed at a 3° inclination. As the ramp inclination increases, the disparities between upward and downward directions become more pronounced. Specifically, the uphill flow consistently exhibits a lower average speed compared to the downhill flow at the same inclination. In general, an increase in inclination is associated with a decrease in forward speed, an increase in lateral speed, and a greater utilization of handrails. Handrail plays a particularly important role in assisting pedestrians down very steep ramps. Furthermore, we found that the influence of flow ratio on walking parameters undergoes a change from level walking to ramp walking scenarios. Notably, for the same flow ratio, the results can vary significantly depending on whether the major flow is uphill or downhill. Our findings provide valuable insights into crowd management on ramps and hold significant implications for the safer design of ramps in subway stations, underpasses, and overpasses.

Intermodal Transportation Challenges in Eastern Europe: Case Study of Romania

Abstract The purpose of this paper is to analyze data from the Romanian intermodal transportation sector and provide an overview of its main terminals (sea, river, road and rail) and the operational challenges faced by its most important logistics service providers. Intermodal transportation (by rail) is encouraged at EU level as a sustainable alternative to current predominant truck haulage. Most research articles outline issues with connectivity, terminal handling infrastructure and cost efficiency as factors hindering large scale adoption. Other authors tend to emphasize the more reliable delivery schedules, reduced road congestion and emissions as drivers of cost competitiveness on medium term. Relevant cargo volume traffic (tons, TEU and ITU) is analyzed at Romania’s main intermodal hubs in the last 10 years (2014-2023) using quantitative and qualitative data to provide a comprehensive overview of its overall competitiveness in this sector. Most Eastern European countries are faced with the same challenge in terms of intermodal transportation: the shortcomings of their supporting network due to insufficient public investment, highlighted by the results from Romania (case study method). Main results show Constanta Port had record cargo traffic in 2023, but its throughput is hindered by constant congestion issues, similar to the highly competitive road sector where intense truck traffic creates bottlenecks on the major roads leading to Western Europe. Cargo is also shipped via the Danube and freight trains, but to a limited extent due to low average speeds and inconsistent reliability along most sectors. The paper highlights the importance of a country’s strategic hubs and their connectivity (sea and/or river ports, main railway lines and road sectors) as a source of future growth and development perspectives, for terminal operators as well as neighboring regions (EU and EEA) through increased business activity.

Assessing school evacuation movement characteristics: Children and adolescents speed and flow over stairs and through exit doorways

AbstractThe available theories of evacuation movements are primarily founded on data gathered from adults, making them potentially unsuitable for children, especially in schools. Consequently, it is necessary to undertake further research to collect data on how children move during evacuations to understand their unique characteristics and disparities compared to adults. In this context, this paper aimed to explore the movement of school children and adolescents as they moved over stairs and through exit doorways during evacuations. The evacuation drill involved 295 school children and adolescents, whose behavior was closely monitored using a series of cameras. During the drill, their movement patterns, including flow and speed, were analyzed over stairs and through doorways. The observations revealed that children exhibited frequent interactions and contact with one another, unlike adults, who tend to maintain personal space. The findings of this study indicated that the average traveling speed over stairs was comparable to previous research, although female adolescents had a lower average speed compared to other groups. The speed and flow of participants passing through doorways were found to vary depending on their age and differed from estimates based on adult data. This study highlights that existing evacuation models fall short of adequately accounting for the dynamics of children, indicating the need for further research to improve the generalizability of evacuation models.

Rapid ejaculator rats are more susceptible to anxiety compared with normal ejaculator rats.

By observation of Sprague-Dawley male rats with different ejaculatory behaviors, we have identified distinct behavioral characteristics in rapid ejaculator rats. To validate these differential behaviors, we conducted multifaceted behavioral experiments on rapid ejaculator rats and normal rats. Through mating experiments, 42 male rats were categorized into 5 rapid ejaculator rats, 29 normal ejaculator rats, and 8 sluggish ejaculator rats according to their ejaculation frequency. We selected 5 rats exhibiting rapid ejaculation and 5 rats with normal ejaculation for participation in the Morris water maze, open-field test, and balance beam experiments. The open-field tests revealed that rapid ejaculator rats spent shorter time in the center region (1.23 ± 1.21 vs. 6.56 ± 2.40 s, P = 0.0041), less entered the center region (0.80 ± 0.75 vs. 3.40 ± 1.50, time, P = 0.0145), traveled shorter distances (17,003.77 ± 3339.42 vs. 25,037.90 ± 5499.94 mm, P = 0.0371), and had a lower average speed compared with normal rats (66.09 ± 62.36 vs. 195.56 ± 83.41 mm/s, P = 0.0377). However, no significant differences were observed in the Morris water maze and balance beam experiments (0.25 ± 0.05 vs. 0.26 ± 0.07, P = 0.7506;16.40 ± 3.77 vs. 16.25 ± 2.05, P = 0.9515). These behavioral results indicated that the rapid ejaculator rats were more prone to anxiety. To further substantiate this claim, we examined Brain-derived neurotrophic factor expression levels in the hippocampus of rat brains using immunohistochemistry and western blotting. The results demonstrate lower Brain-derived neurotrophic factor expression in the hippocampus of rapid ejaculator rats compared with that in normal rats (P = 0.0093). Thus, our experiments indicate that rapid ejaculator rats exhibit a higher propensity for anxiety, potentially linked to their abnormal neurophysiologic state. It is concluded that rapid ejaculator rats may be more susceptible to anxiety on a pathophysiological basis.

Maternal immune activation induces sex-dependent behavioral differences in a rat model of schizophrenia.

Maternal immune activation (MIA) is a mature means to construct a schizophrenia model. However, some preclinical studies have reported that a MIA-induced schizophrenia model seemed to have gender heterogeneity in behavioral phenotype. On the other hand, the MIA's paradigms were diverse in different studies, and many details could affect the effect of MIA. To some extent, it is not credible and scientific to directly compare the gender differences of different MIA programs. Therefore, it is necessary to study whether the sex of the exposed offspring leads to behavioral differences on the premise of maintaining a consistent MIA mode. An animal model of schizophrenia was established by the administration of 10 mg/kg Poly (I: C) when dams were on day 9 of gestation. Then, a number of female and male offspring completed a series of behavioral tests during postnatal days 61-75. Compared with the female control group (n = 14), female MIA offspring (n = 12) showed a longer movement distance (d = 1.07, p < 0.05) and higher average speed (d = 1.08, p < 0.05) in the open field test (OFT). In the Y maze test, the percentage of entering the novel arm of female MIA offspring was lower (d = 0.92, p < 0.05). Compared with the male control group (n = 14), male MIA offspring (n = 13) displayed less movement distance (d = 0.93, p < 0.05) and a lower average speed (d = 0.94, p < 0.05) in the OFT. In the Y maze test, the proportion of exploration time in the novel arm of male MIA offspring was lower (d = 0.96, p < 0.05). In the EPM, male MIA offspring showed less time (d = 0.85, p < 0.05) and a lower percentage of time spent in the open arms (d = 0.85, p < 0.05). Male MIA offspring also had a lower PPI index (76 dB + 120 dB, d = 0.81, p < 0.05; 80 dB + 120 dB, d = 1.45, p < 0.01). Our results showed that the behavioral phenotypes induced by prenatal immune activation were highly dependent on the sex of the offspring.

Chronological age-based vs. Bio-banded friendly football tournament: Effects on physical performance and spatial exploration behaviour in 7v7 match play

ABSTRACT Biological age-based competitions have been suggested to mitigate maturation bias among youth football players. This study analysed the physical demands and spatial exploration behaviour when playing football matches against biological or chronological age-based opposition. One-hundred and sixteen U-13 and U-14 male regional-level football players were recruited from five Portuguese football academies. Each player completed eight games, four per condition (chronological and biological-based), on the same day. Games were played in 7 vs. 7 formats, with 20-min duration, and conformed to standard officiating and rule procedures. The following variables were considered from GPS-data in each game: distance covered, high-intensity accelerations and decelerations, body impacts, and average and peak speeds. Furthermore, average, and peak heart rates (HRpeak) and spatial exploration index were collected. Players covered significantly less distance (ES = 1.11), performed fewer decelerations (ES = 0.82), achieved lower average speeds (ES = 1.15), had fewer body impacts (ES = 0.94), and recorded lower HRpeak (ES = 0.56) in the biological age-based competition compared to the chronological-age-based. No significant differences were found between the two formats in spatial exploration. Both game formats offer distinct physical demands at the external and internal levels. Finally, practitioners can manipulate the type of opposition to get distinct physical demands to mitigate the effect of maturation bias during development.

Wind Turbine-Fuel Cell Power System for Supplying Isolated Sites

The present work aims to develop a dynamic Wind Turbine-Fuel Cell (WT-FC) hybrid power system under Simulink to meet the energy needs of dwellings in the south of Algeria. The Enercon E40 wind turbine model with a rated power of 500 kW was selected. Simulations were performed for four sites, namely Tinfouye, Belkbir, Tabelbala and Tindouf using daily wind data ranging between 2004 and 2018. The results indicated that Tindouf has a high mean speed of 5.57 m/s at 10 m, resulting in a power density of 194 W/m2. However, a low average speed of 4.81 m/s is recorded at the site of Tabelbala. The maximum energy production is recorded at Belkbir reaching 4183.96 MWh/year with 0.9141 C$/kWh. Therefore, a high-power density of 239 W/m² was noted in Tabelbala. In the environmental analysis, Belkbir was found to have the highest avoided carbon dioxide (CO2) emission rate of 1829.64 tons CO2/kWh.

Evaluation of welding procedures to optimize the corrosion performance of AISI 304L pipes

This study aimed to evaluate different TIG welding procedures to optimize the performance of AISI 304L pipes in corrosive applications. For that, samples welded by the TIG process. And samples were produced with the electric current density as a variable. Electric current density with a constant current and current in pulsed mode were used. The electrochemical behavior of the welded joints was evaluated using the potentiodynamic polarization technique and the double pulse potentiokinetic reactivation technique. The microstructural characterization and the area exposed to scanning were performed by optical microscopy and scanning electron microscopy. The results indicated that the 250 Hz pulsed TIG process obtained the noblest electrochemical parameters, and the best performance was attributed to associating low average current density and high welding speed.

APPLICATION OF SELF-ORGANIZING MAP (SOM) ANALYSIS FOR ESTIMATING BICYCLE SHARING: A NEW PERSPECTIVE

Meteorology may be key to forecasting whether people will use it or not (depending on city studied), but so to date, the predictions made have generated some controversy because they have not been analyzed using non-linear analysis. The objective of this study is to analyse the relationship between the time spent using the València bike sharing service (SBC) as a means of active transport and the weather. A self-organising map analysis (SOM) was performed to generate profiles (clusters) of days on SBC use and meteorological factors and a non-parametric analysis was performed to compare the different profiles generated. The results showed 8 profiles of days, which obtained multiple significant differences. These results show that, although there are variables with greater weight than others for estimating the use of the SBC, their relationship is not always linear and a combination of them is needed for greater rigor in the predictions. In this study has been observed that, in order to predict a high use of the SBC, days should be warm if humidity is low to moderate, although temperature is limited if humidity is high, with virtually no precipitation and low average wind speed. On the other hand, to estimate low SBC use, days should be characterized by high relative humidity, precipitation and wind speed. On these days, if the humidity is not high and there is no precipitation, low temperatures would be taken into account. In conclusion, the use of non-linear analyses such as SOM proves to be an effective tool for estimating the use of SBC in relation to meteorology. Keywords: Active transport, bike-sharing, SOM, meteorology, non-lineal analyses.

Influence of ambient temperature on the CO2 emitted of light-duty vehicle

Because of global warming, people have paid more attention to greenhouse gas emitted by vehicles. To quantify the impact of temperature on vehicle CO2 emissions, this study was conducted using the world light vehicle test cycle on two light-duty E10 gasoline vehicles at ambient temperatures of -10, 0, 23, and 40℃, and found that CO2 emission factors of Vehicle 1 in the low-speed phase were 22.07% and 20.22% higher than those of Vehicle 2 at cold start and hot start under -10℃. The reason was vehicle 1 had a larger displacement and more friction pairs than vehicle 2. There was the highest CO2 emission at the low-speed phase due to low average speed, frequent acceleration, and deceleration. The CO2 temperature factor and the ambient temperature had a strong linear correlation (R2 = 0.99). According to CO2 temperature factors and their relationships, CO2 emission factors of other ambient temperatures could be calculated when the CO2 emission factor of 23℃ was obtained, and the method also could be used to obtain the CO2 temperature factors of different vehicles. To separate the effect of load setting and temperature variation on CO2 emission quantitatively, a method was proposed. And results showed that the load setting was dominant for the CO2 emission variation. Compared with 23℃, the CO2 emission for vehicle 1 caused by load setting variation were 62.83 and 47.42 g/km, respectively at -10 and 0℃, while those for vehicle 2 were 45.01 and 35.63 g/km, respectively.

Pedestrian small group behaviour and evacuation dynamics on metro station platform

Crowd at metro stations is usually a mixture of individuals and small groups of families or friends. However, limited research has focused on small group behaviours for metro safe evacuation evaluation and planning. In this study, a field observation at metro stations and a questionnaire survey were conducted to reveal the small group behaviour characteristics with different decision patterns and compactness. A cellular automaton (CA) based simulation model was proposed to reproduce small group behaviours of independent or joint decision pattern, with loose or close contact, reflecting the real-time trade-off between individual efficiency and group coherence. Impacts of small group behaviours on crowd dynamics were investigated by simulation experiments under diverse scenarios. Simulation experiments revealed that joint decision pattern and close contact of small groups were more likely to lead to longer evacuation time, lower average speed and stronger interference on the individuals. Deviations of estimated evacuation time due to small group behaviours were investigated and found to be common and widespread with different group decision pattern and compactness, congestion levels, proportions of groups in the crowd and exit layouts.

Influence of Meteorological Parameters on the Urban Heat Island in Moscow

The urban heat island (UHI) intensity in Moscow and the influence of various meteorological parameters are discussed using weather station data. The maximal and average in-space UHI intensities, i.e., a comparison of air temperature T either in the city centre or in the whole urban area together with rural zone have averaged 1.9 and 0.9 °C, respectively, in recent years. The UHI in Moscow has stabilized over the past decade and is not growing. Under conditions of a strong anticyclone, the maximal UHI intensity in space and time reaches 11–12 °C. Low cloudiness and amplitudes of diurnal air temperature, as well as surface temperature, demonstrate the closest relationship with the UHI intensity among other parameters with the correlation coefficient of up to −0.67 for low cloudiness and the maximal UHI intensity. The effect of wind speed, total cloudiness and relative humidity on the UHI is slightly weaker, but still significant. The relationships of all meteorological parameters with the maximal UHI intensity are closer than those with the average one. The multiple correlation coefficient between the maximal UHI intensity and both parameters (low cloudiness and average daily wind speed) is 0.76–0.82. The UHI intensity function of air temperature has a minimum in the range from −4 to 0 °C; its growth both at lower and higher T is due to the influence of anticyclonic weather. The UHI intensity function of wind speed decreases with wind strength. The threshold value at which this function asymptotically approaches its lower limit is 10 m/s in the 40–200 m air layer. The UHI intensity functions of both total and low cloudiness decrease with increasing cloudiness and the differences between them are significant if the cloud cover is more than 50%.

Assessment of Energy Consumption Characteristics of Ultra-Heavy-Duty Vehicles under Real Driving Conditions

Passenger cars account for the largest share of GHG emissions in the road sector. However, given that the number of heavy-duty vehicles registered is lower but accounts for about a quarter of GHG emissions in the road sector, it is necessary to reduce carbon dioxide (CO2) emissions by improving the fuel efficiency of heavy-duty vehicles. However, experiments using dynamometers during the vehicle development process consume a lot of time and cost. Conversely, simulations can quantitatively analyze the sensitivity of parameters and accelerate optimization. Therefore, in this study, we modeled a heavy-duty vehicle using an AVL Cruise simulation and analyzed the effects of payload, air drag coefficient, and rolling resistance on fuel economy, CO2 emission, and the valid window ratio among the moving average window (MAW) for three driving routes. When the average vehicle speed was higher, the effect of the air drag coefficient on fuel economy was high. Additionally, when the average vehicle speed was lowered, the effect of the reduced rolling resistance on improving fuel efficiency was higher than that of the reducing air drag. Thus, the fuel efficiency improvement rate according to each 10% decrease in rolling resistance was higher by 2.2%, on average, in the low average speed route. Additionally, it was confirmed that the valid window ratio was high when driving in a section with a high vehicle speed first. Thus, the valid window ratio was almost 100% in the test of the route conditions starting from the highway section.

Thermal and Electronic Properties of Ba2MnSe3.

The structural, thermal, and electronic properties of Ba2MnSe3 were investigated. Analysis of the low-temperature heat capacity revealed a low Debye temperature and a low average speed of sound that, together with the bonding in this material, result in a low thermal conductivity over a relatively large temperature range. Density functional theory and calculated electron localization were employed to investigate the electronic structure and bonding. Absorption and photoluminescence spectroscopy measurements corroborated our calculations and revealed a direct band gap of 1.75 eV. This study expands on our understanding of the physical properties of this material and reveals previously unascertained properties, the knowledge of which is imperative for any potential application of interest.

Physiological demands and motion analysis of elite foil fencing.

The aim of this study was to determine the physiological demands and motion analysis of a simulated fencing competition. Eighteen fencers each completed 5 'poule' (5 touches) and 'direct elimination (DE)' (15 touches) fights. Expired gases were measured during 1 poule and DE fight. Heart rate (HR), ratings of perceived exertion (RPE) and movement data were recorded throughout all fights. Motion analysis was undertaken using the software LINCE PLUS. Differences between poule and DE fights were determined by either a paired t-test or a one-way repeated measures ANOVA. HR and RPE were significantly greater during DE compared to poule (170 ±10 vs 163 ±13 beats·min-1; P<0.05). A greater distance was covered during a DE fight compared to a poule fight (459.9 ± 117.7 m vs 162.6 ± 74.2 m; P<0.05). The average values of [Formula: see text] were 42.5 ±5.6 ml·kg-1·min-1 in men and 34.4 ±3.2 ml·kg-1·min-1 in women. Work-to-rest ratios reduced during the DE fights along with a lower average speed and increased max speed (11.7 ± 2.8 km∙h-1 vs 9.6 ± 1.6 km∙h-1; P<0.05). In conclusion, there is an increased physiological demand during a DE fight accompanied by a reduction in average speed and decreased work-to-rest ratio.

Spatially resolved hourly traffic emission over megacity Delhi using advanced traffic flow data

Abstract. This paper presents a bottom-up methodology to estimate multi-pollutant hourly gridded on-road traffic emission using advanced traffic flow and speed data for Delhi. We have used the globally adopted COPERT (Computer Programme to Calculate Emissions from Road Transport) emission functions to calculate the emission as a function of speed for 127 vehicle categories. At first, the traffic volume and congestion (travel time delay) relation is applied to model the 24 h traffic speed and flow for all the major road links of Delhi. The modelled traffic flow and speed shows an anti-correlation behaviour having peak traffic and emissions in morning–evening rush hours. We estimated an annual emission of 1.82 Gg for PM (particulate matter), 0.94 Gg for BC (black carbon), 0.75 Gg for OM (organic matter), 221 Gg for CO (carbon monoxide), 56 Gg for NOx (oxides of nitrogen), 64 Gg for VOC (volatile organic compound), 0.28 Gg for NH3 (ammonia), 0.26 Gg for N2O (nitrous oxide) and 11.38 Gg for CH4 (methane) for 2018 with an uncertainty of 60 %–68 %. The hourly emission variation shows bimodal peaks corresponding to morning and evening rush hours and congestion. The minimum emission rates are estimated in the early morning hours whereas the maximum emissions occurred during the evening hours. Inner Delhi is found to have higher emission flux because of higher road density and relatively lower average speed. Petrol vehicles dominate emission share (&gt;50 %) across all pollutants except PM, BC and NOx, and within them the 2W (two-wheeler motorcycles) are the major contributors. Diesel-fuelled vehicles contribute most of the PM emission. Diesel and CNG (compressed natural gas) vehicles have a substantial contribution in NOx emission. This study provides very detailed spatiotemporal emission maps for megacity Delhi, which can be used in air quality models for developing suitable strategies to reduce the traffic-related pollution. Moreover, the developed methodology is a step forward in developing real-time emission with the growing availability of real-time traffic data. The complete dataset is publicly available on Zenodo at https://doi.org/10.5281/zenodo.6553770 (Singh et al., 2022).

Comparative Assessment of Supervisory Control Algorithms for a Plug-In Hybrid Electric Vehicle

The study examines alternative on-board energy management system (EMS) supervisory control algorithms for plug-in hybrid electric vehicles. The optimum fuel consumption was sought between an equivalent consumption minimization strategy (ECMS) algorithm and a back-engineered commercial rule-based (RB) one, under different operating conditions. The RB algorithm was first validated with experimental data. A method to assess different algorithms under identical states of charge variations, vehicle distance travelled, and wheel power demand criteria is first demonstrated. Implementing this method to evaluate the two algorithms leads to fuel consumption corrections of up to 8%, compared to applying no correction. We argue that such a correction should always be used in relevant studies. Overall, results show that the ECMS algorithm leads to lower fuel consumption than the RB one in most driving conditions. The difference maximizes at low average speeds (&lt;40 km/h), where the RB leads to more frequent low load engine operation. The two algorithms lead to fuel consumption differences of 3.4% over the WLTC, while the maximum difference of 24.2% was observed for a driving cycle with low average speed (18.4 km/h). Further to fuel consumption performance optimization, the ECMS algorithm also appears superior in terms of adaptability to different driving cycles.

Vitamin D, Folic Acid and Vitamin B12 Can Reverse Vitamin D Deficiency-Induced Learning and Memory Impairment by Altering 27-Hydroxycholesterol and S-Adenosylmethionine.

The cholesterol-oxidized metabolite 27-hydroxycholesterol (27-OHC) is synthesized by CYP27A1, which is a key factor in vitamin D and oxysterol metabolism. Both vitamin D and 27-OHC are considered to play important roles in Alzheimer’s disease (AD). The study aims to research the effects of co-supplementation of vitamin D, folic acid, and vitamin B12 on learning and memory ability in vitamin D-deficient mice, and to explore the underlying mechanism. In this study, C57BL/6J mice were fed a vitamin D-deficient diet for 13 weeks to establish a vitamin D-deficient mice model. The vitamin D-deficient mice were then orally gavaged with vitamin D (VD), folic acid (FA), and vitamin B12 (VB12) alone or together for eight weeks. Following the gavage, the learning and memory ability of the mice were evaluated by Morris Water Maze and Novel object recognition test. The CYP27A1-related gene and protein expressions in the liver and brain were determined by qRT-PCR. The serum level of 27-OHC was detected by HPLC-MS. Serum levels of 25(OH)D, homocysteine (Hcy), and S-Adenosylmethionine (SAM) were measured by ELISA. After feeding with the vitamin D-deficient diet, the mice performed longer latency to a platform (p < 0.001), lower average speed (p = 0.026) in the Morris Water Maze, a lower time discrimination index (p = 0.009) in Novel object recognition, and performances were reversed after vitamin D, folic acid and vitamin B12 supplementation alone or together (p < 0.05). The gene expressions of CYP27A1 in the liver and brain were upregulated in the vitamin D-deficiency (VDD) group compared with the control (CON) group (p = 0.015), while it was downregulated in VDD + VD and VDD + VD-FA/VB12 groups compared with the VDD group (p < 0.05), with a similar trend in the protein expression of CYP27A1. The serum levels of 27-OHC were higher in the VDD group, compared with CON, VDD + VD, and VDD + VD-FA/VB12 group (p < 0.05), and a similar trend was found in the brain. The serum 25(OH)D levels were significantly decreased in the vitamin D-deficiency group (p = 0.008), and increased in the vitamin D-supplemented group (p < 0.001). The serum levels of SAM were higher in the B vitamins-supplemented group, compared with CON and VDD groups (p < 0.05). This study suggests that CYP27A1 expression may be involved in the mechanism of learning and memory impairment induced by vitamin D deficiency. Co-supplementation with vitamin D, folic acid, and vitamin B12 significantly reverses this effect by affecting the expression of CYP27A1, which in turn regulates the metabolism of 27-OHC, 25(OH)D, and SAM.

Decarbonization of ASEAN’s power sector: A holistic approach

Coal and natural gas have dominated ASEAN’s power sector in the past and contributed to 77% of power generation in 2019. To achieve net-zero by 2050, ASEAN countries need to decarbonize their power sector in the next three decades. This paper performs a technology screening exercise for ten decarbonization technologies for the power sector based on a holistic approach of sustainability, security, affordability, reliability, technology readiness and technology impact. This exercise has resulted in country-specific ranking of technologies which can inform policymakers of ASEAN countries. Overall speaking, simultaneous utilization of both fossil and non-fossil technologies is needed rather than waiting for certain technologies to mature. On the fossil side, switching from coal to gas for power generation and implementing carbon capture and storage (CCS) in coal- and gas-fired power plants have the highest decarbonization potential. Therefore, eleven first-mover CCS projects are proposed with the potential to mitigate up to 22% of energy-related CO2 emission in ASEAN in 2019. On the renewable side, hydropower has the highest potential but sustainability issues due to overdamming of the Mekong River needs to be addressed. Further addition of capacity will likely come from run-of-the-river hydropower plants. Within ASEAN, there is medium to high potential for further usage of agricultural resides as biomass for power generation, especially in Indonesia,​ Thailand, Malaysia and the Philippines. Solar photovoltaic (PV) has medium potential in ASEAN countries with high land mass but more research and development (R&D) is needed in grid improvement and energy storage technologies. Within ASEAN, wind energy suffers from a low average wind speed but there are exceptions. More R&D is needed in the deign of low wind speed wind turbines. Geothermal resources are found only in Indonesia and the Philippines and are under-utilized. Further implementation will require favorable government polices to incentivize private investment and streamlining permitting, among others. Energy policies that promote rapid decarbonization of ASEAN’s power sector based on our findings are also discussed.

Representative Driving Cycles for Trinidad and Tobago with Slope Profiles for Electric Vehicles

The rise of plug-in battery electric vehicles presents an excellent opportunity for small island developing states such as those of the Caribbean. The vehicles offer improved energy efficiency, enhanced energy security, and reduced foreign exchange expenditure. Incentivizing the uptake of electric vehicles seems to be an obvious policy decision, but there could be unintended consequences. Real-world driving cycles are essential for validating electric-vehicle energy and economic benefits using simulation studies. In drive-cycle methodologies, the microtrip method is the preferred choice for countrywide representation and is ideal for fuel consumption estimations. This paper reports on the first such real-world driving cycle for the Caribbean, specifically Trinidad and Tobago, which is developed using a microtrip construction method with a novel approach to establishing a slope profile. Highway and suburban segments show some distinct characteristics, including relatively high average accelerations and decelerations in the highway and suburban cycles and low average speeds of 40.2 km/h (highway) and 21.74 km/h (suburban). The driving cycle is unique but reasonable when compared with others derived in emerging economies.