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Journal articles on the topic 'HDVs'
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1
Cunanan, Carlo, Manh-Kien Tran, Youngwoo Lee, Shinghei Kwok, Vincent Leung, and Michael Fowler. "A Review of Heavy-Duty Vehicle Powertrain Technologies: Diesel Engine Vehicles, Battery Electric Vehicles, and Hydrogen Fuel Cell Electric Vehicles." Clean Technologies 3, no. 2 (June 1, 2021): 474–89. http://dx.doi.org/10.3390/cleantechnol3020028.
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Greenhouse gas emissions from the freight transportation sector are a significant contributor to climate change, pollution, and negative health impacts because of the common use of heavy-duty diesel vehicles (HDVs). Governments around the world are working to transition away from diesel HDVs and to electric HDVs, to reduce emissions. Battery electric HDVs and hydrogen fuel cell HDVs are two available alternatives to diesel engines. Each diesel engine HDV, battery-electric HDV, and hydrogen fuel cell HDV powertrain has its own advantages and disadvantages. This work provides a comprehensive review to examine the working mechanism, performance metrics, and recent developments of the aforementioned HDV powertrain technologies. A detailed comparison between the three powertrain technologies, highlighting the advantages and disadvantages of each, is also presented, along with future perspectives of the HDV sector. Overall, diesel engine in HDVs will remain an important technology in the short-term future due to the existing infrastructure and lower costs, despite their high emissions, while battery-electric HDV technology and hydrogen fuel cell HDV technology will be slowly developed to eliminate their barriers, including costs, infrastructure, and performance limitations, to penetrate the HDV market.
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Lin, Lei, Siyuan Gong, Srinivas Peeta, and Xia Wu. "Long Short-Term Memory-Based Human-Driven Vehicle Longitudinal Trajectory Prediction in a Connected and Autonomous Vehicle Environment." Transportation Research Record: Journal of the Transportation Research Board 2675, no. 6 (February 19, 2021): 380–90. http://dx.doi.org/10.1177/0361198121993471.
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The advent of connected and autonomous vehicles (CAVs) will change driving behavior and travel environment, and provide opportunities for safer, smoother, and smarter road transportation. During the transition from the current human-driven vehicles (HDVs) to a fully CAV traffic environment, the road traffic will consist of a “mixed” traffic flow of HDVs and CAVs. Equipped with multiple sensors and vehicle-to-vehicle communications, a CAV can track surrounding HDVs and receive trajectory data of other CAVs in communication range. These trajectory data can be leveraged with recent advances in deep learning methods to potentially predict the trajectories of a target HDV. Based on these predictions, CAVs can react to circumvent or mitigate traffic flow oscillations and accidents. This study develops attention-based long short-term memory (LSTM) models for HDV longitudinal trajectory prediction in a mixed flow environment. The model and a few other LSTM variants are tested on the Next Generation Simulation US 101 dataset with different CAV market penetration rates (MPRs). Results illustrate that LSTM models that utilize historical trajectories from surrounding CAVs perform much better than those that ignore information even when the MPR is as low as 0.2. The attention-based LSTM models can provide more accurate multi-step longitudinal trajectory predictions. Further, grid-level average attention weight analysis is conducted and the CAVs with higher impact on the target HDV’s future trajectories are identified.
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Kornfield, Thomas, and Jonathan Skolnik. "Economic Incentives to Mitigate Impacts of State Low-Emission Vehicle Standard for Heavy-Duty Vehicles." Transportation Research Record: Journal of the Transportation Research Board 1520, no. 1 (January 1996): 63–70. http://dx.doi.org/10.1177/0361198196152000108.
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Economic incentive concepts that might reduce the likelihood that heavy-duty vehicle (HDV) operators will move their base operations out of California as a result of potential low-emission standards for HDVs based in the state are examined. In particular, 11 economic incentives that fall into the categories of rebates, taxes and fees, loans, and trading measures are examined. The results support the adoption of a fee-bate system under which registration fees would be based on the emission contributions of HDVs. Such a system could be applied to instate and out-of-state HDVs, thereby eliminating the incentive for operators to relocate outside California while encouraging the purchase and use of low-emission HDVs.
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Oyama, Beatriz Sayuri, Maria de Fátima Andrade, Pierre Herckes, Ulrike Dusek, Thomas Röckmann, and Rupert Holzinger. "Chemical characterization of organic particulate matter from on-road traffic in São Paulo, Brazil." Atmospheric Chemistry and Physics 16, no. 22 (November 18, 2016): 14397–408. http://dx.doi.org/10.5194/acp-16-14397-2016.
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Abstract. This study reports emission of organic particulate matter by light-duty vehicles (LDVs) and heavy-duty vehicles (HDVs) in the city of São Paulo, Brazil, where vehicles run on three different fuel types: gasoline with 25 % ethanol (called gasohol, E25), hydrated ethanol (E100), and diesel (with 5 % biodiesel). The experiments were performed at two tunnels: Jânio Quadros (TJQ), where 99 % of the vehicles are LDVs, and RodoAnel Mário Covas (TRA), where up to 30 % of the fleet are HDVs. Fine particulate matter (PM2.5) samples were collected on quartz filters in May and July 2011 at TJQ and TRA, respectively. The samples were analyzed by thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) and by thermal–optical transmittance (TOT). Emission factors (EFs) for organic aerosol (OA) and organic carbon (OC) were calculated for the HDV and the LDV fleet. We found that HDVs emitted more PM2.5 than LDVs, with OC EFs of 108 and 523 mg kg−1 burned fuel for LDVs and HDVs, respectively. More than 700 ions were identified by TD-PTR-MS and the EF profiles obtained from HDVs and LDVs exhibited distinct features. Unique organic tracers for gasoline, biodiesel, and tire wear have been tentatively identified. nitrogen-containing compounds contributed around 20 % to the EF values for both types of vehicles, possibly associated with incomplete fuel burning or fast secondary production. Additionally, 70 and 65 % of the emitted mass (i.e. the OA) originates from oxygenated compounds from LDVs and HDVs, respectively. This may be a consequence of the high oxygen content of the fuel. On the other hand, additional oxygenation may occur during fuel combustion. The high fractions of nitrogen- and oxygen-containing compounds show that chemical processing close to the engine / tailpipe region is an important factor influencing primary OA emission. The thermal-desorption analysis showed that HDVs emitted compounds with higher volatility, and with mainly oxygenated and longer chain hydrocarbons than LDVs.
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Weinblatt, Herbert, Robert G. Dulla, and Nigel N. Clark. "Vehicle Activity–Based Procedure for Estimating Emissions of Heavy-Duty Vehicles." Transportation Research Record: Journal of the Transportation Research Board 1842, no. 1 (January 2003): 64–72. http://dx.doi.org/10.3141/1842-08.
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A new procedure for estimating the emissions of heavy-duty vehicles (HDVs) is presented. This procedure combines second-by-second data on actual in-use speed and acceleration of HDVs with data on average emissions rates of HDVs operating at corresponding speeds and acceleration rates. The initial implementation of this procedure used a limited amount of newly collected emissions data and a somewhat larger amount of previously collected HDV activity data. Validation tests provide a reasonable level of confidence about the validity of the nitrogen oxide (NOx) emissions factors produced using this initial implementation. However, these tests also indicate that the small amount of emissions data used in the initial implementation is insufficient to produce meaningful estimates of emissions factors for carbon monoxide or particulate matter. The research, the procedure that was developed, the validation tests, the results for NOx emissions, and NOx speed correction factors derived from these results are briefly described. The speed correction factors are of particular interest. The minimum values for these factors occur at speeds higher than those currently used by the U.S. Environmental Protection Agency, and the factors grow more slowly at higher speeds than do the factors generated by MOBILE.
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O'Doherty, T., D. A. Egarr, M. G. Faram, I. Guymer, and N. Syred. "Residence time study of a hydrodynamic vortex separator applied to predicting disinfection performance." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223, no. 3 (May 22, 2009): 113–22. http://dx.doi.org/10.1243/09544089jpme244.
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The fluid residence time characterization of a 3.4 m diameter hydrodynamic vortex separator (HDVS) has been carried out under laboratory conditions. Computational fluid dynamics (CFD) modelling has then been undertaken for the same conditions at which the experimental data were collected and validated against the experimental results, for which reasonable correspondence has been found. Using the results from the CFD modelling and batch inactivation results from the disinfection of secondary treated wastewater, it is shown that the theoretical performance of an HDVS as a contact vessel for disinfection can be determined and the practical applicability of an HDVS for disinfection is confirmed.
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Shi, Mingming, Yunjie Ruan, Binxin Wu, Zhangying Ye, and Songming Zhu. "Performance evaluation of Hydrodynamic Vortex Separator at different hydraulic retention times applied in Recirculating Biofloc Technology system." Transactions of the ASABE 60, no. 5 (2017): 1737–47. http://dx.doi.org/10.13031/trans.12415.
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Abstract. Recirculating biofloc technology (RBFT) has been gradually acknowledged for its positive effect on the control of biofloc concentration using a hydrodynamic vortex separator (HDVS). To operate an RBFT system at maximum performance, the removal efficiency of an HDVS at different hydraulic retention times (HRTs) must be fully predictable. Hence, a numerical study of the fluid flow and particle dynamics was performed to characterize the performance of an HDVS at varying HRTs. First, flow simulation was conducted to determine an economical mesh size at an HRT of 248 s. Then, with respect to the total suspended solids (TSS) in the RBFT system and the physical properties of the flocs, two-way coupling of the dense discrete phase model (DDPM) and discrete element model (DEM) methods was used to predict floc tracking in an HDVS. Additionally, the Reynolds averaged Navier-Stokes (RANS) equations with the Reynolds stress turbulence model (RSM) were solved using the finite volume method based on the semi-implicit method pressure-linked equations (SIMPLE) pressure correction algorithm in the computational domain. Finally, pilot-scale studies were conducted to verify the simulation models. Based on the simulation results, floc management in an RBFT system is briefly discussed. Due to limited research on the numerical simulation and operating conditions of an HDVS in an RBFT system, this article describes an original investigation of the modeling approach. Keywords: Computational fluid dynamics, Dense discrete phase model, Discrete element model, Floc management, Flow field, Removal efficiency, Total suspend solids.
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Christensen, Tine N., Seppo W. Langer, Gitte Persson, Klaus Richter Larsen, Annemarie G. Amtoft, Sune H. Keller, Andreas Kjaer, and Barbara Malene Fischer. "Impact of [18F]FDG-PET and [18F]FLT-PET-Parameters in Patients with Suspected Relapse of Irradiated Lung Cancer." Diagnostics 11, no. 2 (February 11, 2021): 279. http://dx.doi.org/10.3390/diagnostics11020279.
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Radiation-induced changes may cause a non-malignant high 2-deoxy-2-[18F]fluoro-d-glucose (FDG)-uptake. The 3′-deoxy-3′-[18F]fluorothymidine (FLT)-PET/CT performs better in the differential diagnosis of inflammatory changes and lung lesions with a higher specificity than FDG-PET/CT. We investigated the association between post-radiotherapy FDG-PET-parameters, FLT-PET-parameters, and outcome. Sixty-one patients suspected for having a relapse after definitive radiotherapy for lung cancer were included. All the patients had FDG-PET/CT and FLT-PET/CT. FDG-PET- and FLT-PET-parameters were collected from within the irradiated high-dose volume (HDV) and from recurrent pulmonary lesions. For associations between PET-parameters and relapse status, respectively, the overall survival was analyzed. Thirty patients had a relapse, of these, 16 patients had a relapse within the HDV. FDG-SUVmax and FLT-SUVmax were higher in relapsed HDVs compared with non-relapsed HDVs (median FDG-SUVmax: 12.8 vs. 4.2; p < 0.001; median FLT-SUVmax 3.9 vs. 2.2; p < 0.001). A relapse within HDV had higher FDG-SUVpeak (median FDG-SUVpeak: 7.1 vs. 3.5; p = 0.014) and was larger (median metabolic tumor volume (MTV50%): 2.5 vs. 0.7; 0.014) than the relapsed lesions outside of HDV. The proliferative tumor volume (PTV50%) was prognostic for the overall survival (hazard ratio: 1.07 pr cm3 [1.01–1.13]; p = 0.014) in the univariate analysis, but not in the multivariate analysis. FDG-SUVmax and FLT-SUVmax may be helpful tools for differentiating the relapse from radiation-induced changes, however, they should not be used definitively for relapse detection.
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Tanaka, Hiroshi, and Laurence J. Thorpe. "The Sony PCL HDVS Production Facility." SMPTE Journal 100, no. 6 (June 1991): 404–15. http://dx.doi.org/10.5594/j01669.
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Gong, Bowen, Ruixin Wei, Dayong Wu, and Ciyun Lin. "Fleet Management for HDVs and CAVs on Highway in Dense Fog Environment." Journal of Advanced Transportation 2020 (August 14, 2020): 1–21. http://dx.doi.org/10.1155/2020/8842730.
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Adverse weather conditions have a significant impairment on the safety, mobility, and efficiency of highway networks. Dense fog is considered the most dangerous within the adverse weather conditions. As to improve the traffic flow throughput and driving safety in dense fog weather condition on highway, this paper uses a mathematical modeling method to study and control the fleet mixed with human-driven vehicles (HDVs) and connected automatic vehicles (CAVs) in dense fog environment on highway based on distributed model predictive control algorithm (DMPC), along with considering the car-following behavior of HDVs driver based on cellular automatic (CA) model. It aims to provide a feasible solution for controlling the mixed flow of HDVs and CAVs more safely, accurately, and stably and then potentially to improve the mobility and efficiency of highway networks in adverse weather conditions, especially in dense fog environment. This paper explores the modeling framework of the fleet management for HDVs and CAVs, including the state space model of CAVs, the car-following model of HDVs, distributed model predictive control for the fleet, and the fleet stability analysis. The state space model is proposed to identify the status of the feet in the global state. The car-following model is proposed to simulate the driver behavior in the fleet in local. The DMPC-based model is proposed to optimize rolling of the fleet. Finally, this paper used the Lyapunov stability principle to analyze and prove the stability of the fleet in dense fog environment. Finally, numerical experiments were performed in MATLAB to verify the effectiveness of the proposed model. The results showed that the proposed fleet control model has the ability of local asymptotic stability and global nonstrict string stability.
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Andoh, R. Y. G., and A. J. Saul. "The use of hydrodynamic vortex separators and screening systems to improve water quality." Water Science and Technology 47, no. 4 (February 1, 2003): 175–83. http://dx.doi.org/10.2166/wst.2003.0248.
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The paper reviews the evolution of Hydrodynamic Vortex Separators (HDVS) in the context of their application as high rate rotary flow separators for achieving water quality improvements to meet with regulatory requirements in Europe and North America. The types of HDVS and their application for the control of wet-weather discharges such as combined sewer overflows (CSOs), sanitary sewer overflows (SSOs) and stormwater are outlined and a number of myths surrounding their use, dispelled. Reference is made to outputs of peer reviewed comprehensive monitoring, evaluation and demonstration projects on pilot and full-scale installations to demonstrate the efficacy and extensive track record of these systems. Recent developments and innovations in HDVS technologies are discussed, focusing on their combined use as solids liquid separators, contact vessels for wastewater disinfection, the incorporation of self-cleansing screening devices for the control of aesthetic pollutants (e.g. floatables) and the use of computational modelling for optimisation.
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O'Doherty, T., D. A. Egarr, M. G. Faram, I. Guymer, and N. Syred. "Assessment of residence time in a hydrodynamic vortex separator by applying distribution models." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223, no. 3 (April 15, 2009): 179–88. http://dx.doi.org/10.1243/09544089jpme224.
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A number of models exist to simulate the residence time distribution (RTD) of a system or process. Four of these models known as the tanks in series model, axial dispersion model (ADM), aggregated dead zone model, and the advection dispersion equation, have been used to assess which is most suitable for representing the RTD of a hydrodynamic vortex separator (HDVS) when compared to RTD measurements taken under laboratory conditions on a full-scale 3.4 m diameter unit. Computational fluid dynamics (CFD) is also used to model the HDVS and compare with the RTD models and experimental measurements. It has been shown that the fit by each of the RTD models to observed RTDs vary quite considerably, with the ADM being the most appropriate for the HDVS studied, based on having the highest R t2 value. Given the number of model variables that influence CFD predictions, the outputs from the CFD models appear to be reasonable.
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Jiang, Luo, Jie Ji, Yue Ren, Hong Wang, and Yanjun Huang. "Risk Modeling and Quantification of a Platoon in Mixed Traffic Based on the Mass-Spring-Damper Model." Journal of Advanced Transportation 2020 (July 8, 2020): 1–12. http://dx.doi.org/10.1155/2020/7475682.
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Connected and automated vehicle (CAV) technologies have great potential to improve road safety. However, an emerging type of mixed traffic flow with human-driven vehicles (HDVs) and CAVs has also arisen in recent years. To improve the overall safety of this mixed traffic flow, a novel car-following model is proposed to control the driving behaviors of the above two types of vehicles in a platoon from the perspective of a mechanical system, mass-spring-damper (MSD) system. Furthermore, a quantitative index is proposed by incorporating the psychological field theory into the MSD model. The errors of spacing and speed in the car-following processes can be expressed as the accumulation of the virtual total energy, and the magnitude of the energy is used to reflect the danger level of vehicles in the mixed platoon. At the same time, the optimization model of minimum total energy is solved under the constraints of vehicle dynamics and the mechanical characteristics of the MSD system, and the optimal solutions are used as the parameters of the MSD car-following model. Finally, a mixed platoon composed of 3 CAVs and 2 HDVs without performing lane changing is tested using the driver-in-the-loop test platform. The test results show that, in the mixed platoon, CAVs can optimally adjust the intervehicle spacing by making full use of the braking distance, which also provides sufficient reaction time for the driver of HDV to avoid rear-end collisions. Furthermore, in the early stage of the emergency braking, the spacing error is the dominant factor influencing the car-following behaviors, but in the later stage of emergency braking, the speed error becomes the decisive factor of the car-following behaviors. These results indicate that the proposed car-following model and quantitative index are of great significance for improving the overall safety of the mixed traffic flow with CAVs and HDVs.
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Villiers, Marie-Bernadette, Jean-Claude Cortay, Sandra Cortès, Bénédicte Bloquel, Ségolène Brichler, Carine Brakha, Alan Kay, et al. "Protein-Peptide Arrays for Detection of Specific Anti-Hepatitis D Virus (HDV) Genotype 1, 6, and 8 Antibodies among HDV-Infected Patients by Surface Plasmon Resonance Imaging." Journal of Clinical Microbiology 53, no. 4 (January 28, 2015): 1164–71. http://dx.doi.org/10.1128/jcm.03002-14.
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Liver diseases linked to hepatitis B-hepatitis D virus co- or superinfections are more severe than those during hepatitis B virus (HBV) monoinfection. The diagnosis of hepatitis D virus (HDV) infection therefore remains crucial in monitoring patients but is often overlooked. To integrate HDV markers into high-throughput viral hepatitis diagnostics, we studied the binding of anti-HDV antibodies (Abs) using surface plasmon resonance imaging (SPRi). We focused on the ubiquitous HDV genotype 1 (HDV1) and the more uncommon African-HDV6 and HDV8 genotypes to define an array with recombinant proteins or peptides. Full-length and truncated small hepatitis D antigen (S-HDAg) recombinant proteins of HDV genotype 1 (HDV1) and 11 HDV peptides of HDV1, 6, and 8, representing various portions of the delta antigen were grafted onto biochips, allowing SPRi measurements to be made. Sixteen to 17 serum samples from patients infected with different HDV genotypes were injected onto protein and peptide chips. In all, Abs against HDV proteins and/or peptides were detected in 16 out of 17 infected patients (94.12%), although the amplitude of the SPR signal varied. The amino-terminal part of the protein was poorly immunogenic, while epitope 65-80, exposed on the viral ribonucleoprotein, may be immunodominant, as 9 patient samples led to a specific SPR signal on peptide 65 type 1 (65#1), independently of the infecting genotype. In this pilot study, we confirmed that HDV infection screening based on the reactivity of patient Abs against carefully chosen HDV peptides and/or proteins can be included in a syndrome-based viral hepatitis diagnostic assay. The preliminary results indicated that SPRi studying direct physical HDAg–anti-HDV Ab interactions was more convenient using linear peptide epitopes than full-length S-HDAg proteins, due to the regeneration process, and may represent an innovative approach for a hepatitis syndrome–viral etiology-exploring array.
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Egarr, D. A., M. G. Faram, T. O'Doherty, D. A. Phipps, and N. Syred. "Computational fluid dynamic prediction of the residence time distribution of a prototype hydrodynamic vortex separator operating with a base flow component." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 219, no. 1 (February 1, 2005): 53–67. http://dx.doi.org/10.1243/095440805x7017.
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A hydrodynamic vortex separator (HDVS) has been modelled using computational fluid dynamics (CFD) in order to accurately determine the residence time of the fluid at the two outlets of the HDVS using a technique that was developed for use in heating, ventilation, and air conditioning (HVAC). The results have been compared with experimental data [1]. It is shown that, in using CFD, it is possible to study the response to a variety of inputs, and also to determine the mean residence time of the fluid within the separator. Although the technique used for determining the residence time was developed for use in HVAC, it is shown here to be applicable for the analysis of hydraulic systems, specifically, wastewater treatment systems.
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Plowright, Andrew, Riccardo Tortini, and Nicholas Coops. "Determining Optimal Video Length for the Estimation of Building Height through Radial Displacement Measurement from Space." ISPRS International Journal of Geo-Information 7, no. 9 (September 18, 2018): 380. http://dx.doi.org/10.3390/ijgi7090380.
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We presented a methodology for estimating building heights in downtown Vancouver, British Columbia, Canada, using a high definition video (HDV) recorded from the International Space Station. We developed an iterative routine based on multiresolution image segmentation to track the radial displacement of building roofs over the course of the HDV, and to predict the building heights using an ordinary least-squares regression model. The linear relationship between the length of the tracking vector and the height of the buildings was excellent (r2 ≤ 0.89, RMSE ≤ 8.85 m, p < 0.01). Notably, the accuracy of the height estimates was not improved considerably beyond 10 s of outline tracking, revealing an optimal video length for estimating the height or elevation of terrestrial features. HDVs are demonstrated to be a viable and effective data source for target tracking and building height prediction when high resolution imagery, spectral information, and/or topographic data from other sources are not available.
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Pyscher, Tracey. "Domestic Violence and Girlhood: The Making and Breaking of a Disordered Subjectivity." Cultural Studies ↔ Critical Methodologies 17, no. 5 (October 19, 2016): 399–405. http://dx.doi.org/10.1177/1532708616674992.
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This article examines the resistive actions and discourses that shape and reshape the hegemonic and resistant interplay between female youth with histories of domestic violence (HDVs) and educators. Taken out of a larger critical ethnographic study, discussion demonstrates how one urban middle school girl with an HDV is positioned as an object of “emotional and behavioral disorder” and how she responded to violating pedagogies through performances of cultural resistance built out of her social experience of domestic violence. The article draws upon theoretical and methodological insights, including Butler’s notion of performativity, Scott’s theory of resistance, Hill-Collins’s standpoint theory, as well as Scollon and Scollon’s mediated discourse analysis. Similar to the girls in this study, sharing an identity of being a survivor of domestic violence herself, the author discusses how she and female participants (re)worked and (re)wrote agentic social moments in the field. Telling girls’ stories through counter-narratives and participatory research practices helps to reposition the often deficit subjectivities ascribed to girls with HDV.
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Meroney, Robert N., and Robert E. Sheker. "Removing Grit During Wastewater Treatment:CFD Analysis of HDVS Performance." Water Environment Research 88, no. 5 (May 1, 2016): 438–48. http://dx.doi.org/10.2175/106143015x14212658614478.
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Conlon, James, and Jane Lin. "Greenhouse Gas Emission Impact of Autonomous Vehicle Introduction in an Urban Network." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 5 (April 3, 2019): 142–52. http://dx.doi.org/10.1177/0361198119839970.
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This study attempts to quantify the change in carbon dioxide (CO2) emissions resulting from autonomous vehicle (AV) introduction in a congested urban network. An integrated traffic microsimulation and emission model is introduced, described, and used to estimate emissions for different AV penetration scenarios ranging from 0% to 100%. AVs show potential to reduce total CO2 emissions at a network scale, approaching 4% reduction at full autonomy, assuming the same fuel technology in AV as in today’s fleet. Furthermore, it is found that this reduction is sensitive to the penetration ratio of AVs, and is greatest at full AV penetration; AV penetration may generate greater total vehicular CO2 emissions than 0% AV penetration does, contrary to popular belief. This may be because of the heterogeneity in a mixed traffic environment of human-driven vehicles (HDVs) and AVs, as well as the complex interaction between HDVs and AVs that is not yet fully understood.
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Movaghar, Sara, Mahmoud Mesbah, and Meeghat Habibian. "Optimum Location of Autonomous Vehicle Lanes: A Model Considering Capacity Variation." Mathematical Problems in Engineering 2020 (May 12, 2020): 1–13. http://dx.doi.org/10.1155/2020/5782072.
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This paper proposes a model to find the optimal location of autonomous vehicle lanes in a transportation network consisting of both Autonomous Vehicles (AVs) and Human-Driven Vehicles (HDVs) while accounting for the roadway capacity variation. The main contribution of the model is considering a generalized definition of capacity as a function of AV proportion on a link and incorporating it into the network design problem. A bilevel optimization model is proposed with total travel time as the objective function to be minimized. At the upper-level problem, the optimal locations of AV lanes are determined, and at the lower level which is a multiclass equilibrium assignment, road users including both AVs and HDVs seek to minimize their individual travel times. It is shown that if capacity variation is ignored, the effect of AV lane deployment can be misleading. Since there will be a long transition period during which both AVs and HDVs will coexist in the network, this model can help the network managers to optimally reallocate the valuable road space and better understand the effects of AV lane deployment at the planning horizon as well as during the transition period. Employing this model as a planning tool presents how the proposed AV lane deployment plan could consider the AV market penetration growth during the transition period. Numerical analysis based on the Sioux Falls network is presented in two cases with and without variable capacity to illustrate the application of this model. At the 60% penetration rate of AVs, the improvement in total travel time was 3.85% with a fix capacity while this improvement was 9.88% with a variable capacity.
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Miller, Terry L., Wayne T. Davis, Gregory D. Reed, Prakash Doraiswamy, and Joshua S. Fu. "Characteristics and Emissions of Heavy-Duty Vehicles in Tennessee Under the MOBILES Model." Transportation Research Record: Journal of the Transportation Research Board 1842, no. 1 (January 2003): 99–108. http://dx.doi.org/10.3141/1842-12.
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Heavy-duty vehicle (HDV) classifications used for modeling emissions in the MOBILE6 model have been expanded from 2 classifications in MOBILE5 to 16 classifications in MOBILE6. The new classifications are based on vehicle weight and fuel used (i.e., gasoline or diesel). The heavier vehicles have higher emissions, so it is important to use correct vehicle weight distributions. Tennessee’s HDV registration data show a distribution very similar to the national defaults, but with more vehicles in the heaviest weight category (HDV8B). More than 50% of Tennessee’s HDVs fall in the lightest vehicle category (HDV2B). The biggest difference in truck characteristics in Tennessee versus national defaults in MOBILE6 is the higher HDV fraction on Tennessee rural Interstates. Also, the ratio of single-unit trucks to trailer trucks varies considerably by facility type. The emissions of volatile organic compounds and carbon monoxide per mile of travel of gasoline-fueled single-unit trucks can be 2.5 to 5 times higher than those of heavy-duty diesel trailer trucks. The emissions of nitrogen oxides per mile of travel of diesel-fueled tractor–trailer trucks can be five times higher than those of gasoline-fueled single-unit trucks. For these reasons it is important to accurately characterize the HDV fleet. The characteristics of the Tennessee HDV fleet are compared with national defaults used in MOBILE6, and a new scheme for classifying vehicles by road type is presented.
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Bang, Soohyuk, and Soyoung Ahn. "Mixed Traffic of Connected and Autonomous Vehicles and Human-Driven Vehicles: Traffic Evolution and Control using Spring-Mass-Damper System." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 7 (May 29, 2019): 504–15. http://dx.doi.org/10.1177/0361198119847618.
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This paper sheds light on mixed-traffic dynamics considering the differences in driving characteristics, namely acceleration/deceleration rate, desired speed, and response time, between connected and autonomous vehicles (CAVs) and human-driven vehicles (HDVs). In light traffic, these differences were found to induce platoon formations, headed by vehicles with a lower acceleration rate and propensity not to exceed the desired speed (HDV in this study). Platoon formations lead to large inter-platoon spacing that can be utilized to accommodate cut-in vehicles. In a near-capacity condition, however, the differences in driving characteristics can induce voids and undermine traffic throughput when traffic is disturbed by merging vehicles. Based on these findings, a simple CAV control method is proposed based on the spring-mass-damper (SMD) system approach that directly considers the HDV behavior to mitigate disturbance propagation and throughput reduction. The main principle is to adjust the control parameters (lower spring coefficient and higher damping coefficient in the SMD control model) with an aim to control CAVs to absorb the cut-in impact (i.e., spacing shortage) before it reaches the first upstream HDV. A simulation experiment suggests the feasible region of the control parameters, subject to the recovery time, the number of controllable CAVs, and the cut-in impact.
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Karpate, Yogita, Sumit Sharma, and S. Sundar. "Modeling fuel efficiency for heavy duty vehicles (HDVs) in India." Energy Efficiency 11, no. 6 (March 13, 2018): 1483–95. http://dx.doi.org/10.1007/s12053-018-9640-x.
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Attiku, Keren, Joseph Bonney, Esinam Agbosu, Evelyn Bonney, Peter Puplampu, Vincent Ganu, John Odoom, et al. "Circulation of hepatitis delta virus and occult hepatitis B virus infection amongst HIV/HBV co-infected patients in Korle-Bu, Ghana." PLOS ONE 16, no. 1 (January 7, 2021): e0244507. http://dx.doi.org/10.1371/journal.pone.0244507.
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Background Within HIV/HBV infected patients, an increase in HDV infection has been observed; there is inadequate information on HDV prevalence as well as virologic profile in Ghana. This study sought to determine the presence of HDV in HIV/HBV co-infected patients in Ghana. Methods This was a longitudinal purposive study which enrolled 113 HIV/HBV co-infected patients attending clinic at Korle-Bu Teaching Hospital (KBTH) in Accra, Ghana. After consenting, 5 mL whole blood was collected at two-time points (baseline and 4–6 months afterwards). The sera obtained were tested to confirm the presence of HIV, HBV antibodies and/or antigens, and HBV DNA. Antibodies and viral RNA were also determined for HDV. Amplified HBV DNA and HDV RNA were sequenced and phylogenetic analysis carried out with reference sequences from the GenBank to establish the genotypes. Results Of the 113 samples tested 63 (55.7%) were females and 50 (44.25%) were males with a median age of 45 years. A total of 100 (88.5%) samples had detectable HBV surface antigen (HBsAg), and 32 out of the 113 had detectable HBV DNA. Nucleotide sequences were obtained for 15 and 2 samples of HBV and HDV, respectively. Phylogenetic analysis was predominantly genotype E for the HBVs and genotype 1 for the HDVs. Of the 13 samples that were HBsAg unreactive, 4 (30.8%) had detectable HBV DNA suggesting the incidence of occult HBV infections. The percentage occurrence of HDV in this study was observed to be 3.54. Conclusion Our data suggest the presence and circulation of HDV and incidence of occult HBV infection in HIV/HBV co-infected patients in Ghana. This informs health staff and makes it imperative to look out for the presence of HDV and occult HBV in HIV/HBV co-infected patients presenting with potential risk of liver cancers and HBV transmission through haemodialysis and blood transfusions.
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Oh, Yunjung, and Sungwook Park. "Modeling and Parameterization of Fuel Economy in Heavy Duty Vehicles (HDVs)." Energies 7, no. 8 (August 13, 2014): 5177–200. http://dx.doi.org/10.3390/en7085177.
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Suchanek, Michał. "The costs of retrofitting smart tachographs in HDVS in European Union." Transport Economics and Logistics 77 (December 17, 2018): 125–30. http://dx.doi.org/10.26881/etil.2018.77.12.
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The paper focuses on the costs connected with the idea of retrofitting smart tachographs in all heavy duty vehicles in the European Union. Such a motion has been proposed, in order to increase the road safety. The new class of tachographs, ie. the smart tachographs are supposed to be fitted with a GNSS device ensuring a constant monitoring of the vehicle’s speed and other parameters but also a transmitter which should allow to send data in real time without the necessity to download the data manually. However, such a vast process will generate severe costs for the Member States’ administration but also for private companies which will need to handle the cost of fitting the device in their vehicles. The purpose of the article is to estimate this cost.
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Salehi, Vahid Douzloo. "APPLICATION OF A HOLISTIC APPROACH OF HYDROGEN INTERNAL COMBUSTION ENGINE (HICE) BUSSES." Proceedings of the Design Society 1 (July 27, 2021): 477–86. http://dx.doi.org/10.1017/pds.2021.48.
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AbstractHydrogen is a promising fuel to fulfil climate goals and future legislation requirements due to its carbon-free property. Especially hydrogen fueled buses and heavy-duty vehicles (HDVs) strongly move into the foreground. In contrast to the hydrogen-based fuel cell technology, which is already in commercial use, vehicles with hydrogen internal combustion engines (H2-ICE) are also a currently pursued field of research, representing a potentially holistic carbon-free drive train. Real applications of H2-ICE vehicles are currently not known but can be expected, since their suitability is put to test in a few insolated projects at this time. This paper provides a literature survey to reflect the current state of H2-ICEs focused on city buses. An extended view to HDVs and fuel cell technology allows to recognize trends in hydrogen transport sector, to identify further research potential and to derive useful conclusion. In addition, within this paper we apply green MAGIC as a holistic approach and discuss Well-to-Tank green hydrogen supply in relation to a H2-ICE city bus. Building on that, we introduce the upcoming Hydrogen-bus project, where tests of H2-ICE buses in real driving mode are foreseen to investigate Tank-to-Wheel.
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Sakthivel, Erulappan, Veluchamy Malathi, and Muruganantham Arunraja. "BUTHA: Boost Up Clock Terminal with Heuristic Approach for NoC." Journal of Circuits, Systems and Computers 27, no. 06 (February 22, 2018): 1850084. http://dx.doi.org/10.1142/s0218126618500846.
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In recent days, there has been a growing interest in network-on-chip (NoC), as it offers a promising architecture for future systems on-chip (SoC). The performance degradation is the major problem in designing NoC, due to the complexity in designing a traffic generator and traffic estimator (TE) modules. In the conventional NoC design, new traffic modules and low-power algorithms (LPAS) are introduced. A LPA with an NoC has given performance degradation in the transmission rate, end-to-end delay and overall energy consumption. To address this power issue, we modeled the Menger’s theorem (MT) (graph theory (GT))-based clock boosting mechanism to produce an effective frequency for the router. The following two methods are introduced to improve the performance of NoCs: (i) development of a real-time traffic generation module and software-based traffic estimator (STE) (ii) GT approach is introduced into a dynamic frequency scaling (DFS) LPA. In general, the frequency selection process during various traffic conditions in history-based dynamic voltage scaling algorithm (HDVS) and history-based DFS algorithm (HDFS) is more complex and it gives performance degradation. In the proposed method, MT-based DFS (MT-DFS) parameters are estimated under various conditions using both 65 and 90[Formula: see text]nm TSMC CMOS technology. In comparison with conventional HDFS, the evaluations show that MT-DFS interface achieves 67.7% energy saving, 85% dynamic power savings of the links in the on-chip network and 74.27% leakage power saving of the link.
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He, Yi, Xinping Yan, Duanfeng Chu, Xiao-Yun Lu, and Chaozhong Wu. "A Probabilistic Prediction Model for the Safety Assessment of HDVs Under Complex Driving Environments." IEEE Transactions on Intelligent Transportation Systems 18, no. 4 (April 2017): 858–68. http://dx.doi.org/10.1109/tits.2016.2592699.
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Egarr, D., M. G. Faram, T. O'Doherty, D. Phipps, and N. Syred. "Computational fluid dynamic prediction of the residence time of a vortex separator applied to disinfection." Water Science and Technology 52, no. 3 (August 1, 2005): 29–36. http://dx.doi.org/10.2166/wst.2005.0058.
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A Hydrodynamic Vortex Separator (HDVS) has been modelled using Computational Fluid Dynamics (CFD) in order to predict the residence time of the fluid at the overflow and underflow outlets. A technique which was developed for use in Heating, Ventilation and Air Conditioning (HVAC) was used to determine the residence time and the results have been compared with those determined experimentally. It is shown that in using CFD, it is possible to predict the mean residence time of the fluid and to study the response to a pulse injection of tracer. It is also shown that it is possible to apply these techniques to predict the mean survival rate of bacteria in a combined separation and disinfection process.
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Shi, Yunpeng, Qing He, and Zhitong Huang. "Capacity Analysis and Cooperative Lane Changing for Connected and Automated Vehicles: Entropy-Based Assessment Method." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 8 (April 28, 2019): 485–98. http://dx.doi.org/10.1177/0361198119843474.
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Connected and automated vehicles (CAVs) are poised to transform how we manage and control the existing traffic. CAVs can provide accurate distance sensing and adaptive cruise control which make shorter headway possible, and will eventually increase the roadway throughput or capacity. The vehicle-to-vehicle (V2V) communication technology equipment on CAVs allows vehicles to exchange information and form platoons more efficiently. This paper uses the intelligent driver model (IDM) as the behavior model to simulate CAVs in mixed traffic conditions with both CAVs and human-driven vehicles (HDVs) under different CAV penetration rates. A cooperative CAV lane-changing model is introduced to build more CAV platoons. The model develops two lane-changing algorithms. Partial CAV lane change (PAL) is applied at low CAV percentages, whereas full CAV lane change (FAL) is used at high CAV percentages. In addition, block entropy is employed as a performance measure for lane-changing results. The simulation experiments show that capacity will increase as the CAV percentage grows, and the peak growth rates occur in medium CAV percentage between 40% and 70%. The cooperative CAV lane-changing algorithm is found to decrease HDV–CAV conflicts remarkably by 37% as well as to marginally increase capacity by 2.5% under all CAV percentages. The simulation performance suggests that the threshold of CAV penetration rate for switching PAL to FAL is approximately 55%. Furthermore, it is demonstrated that block entropy can measure CAV lane-changing performance efficiently and represent capacity changes to some extent.
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Mendoza, Joseph Albert, Dong Hoon Lee, Sang-Il Lee, and Joo-Hyon Kang. "Structural improvements on hydrodynamic separators: a computational fluid dynamics approach." Water Science and Technology 74, no. 12 (October 4, 2016): 2898–908. http://dx.doi.org/10.2166/wst.2016.462.
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Hydrodynamic separators (HDSs) have been used extensively to reduce stormwater pollutants from urbanized areas before entering the receiving water bodies. They primarily remove particulates and associated pollutants using gravity settling. Two types of HDSs with different structural configurations of the inner vortex-inducing components were presented in this study. One configuration consisted of a dip cylindrical plate with a center shaft while the other one has a hollow screen inside. With the help of computational fluid dynamics, the performance of these different types of HDSs have been evaluated and comparatively analyzed. The results showed that the particle removal efficiency was better with the cylindrical plate type HDSs than the screen type HDSs because of the larger swirling flow regime formed inside the device. Plate type HDSs were found more effective in removing fine particles (∼50 μm) than the screen type HDSs that were only efficient in removing large particles (≥250 μm). Structural improvements in a HDS such as increase in diameter and angle of the inlet pipe can enhance the removal efficiencies by up to 20% for plate type HDS while increase in the screen diameter can increase removal efficiencies of the screen type HDS.
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Le Gal, Frédéric, Samira Dziri, Athenaïs Gerber, Chakib Alloui, Zahia Ben Abdesselam, Dominique Roulot, Ségolène Brichler, and Emmanuel Gordien. "Performance Characteristics of a New Consensus Commercial Kit for Hepatitis D Virus RNA Viral Load Quantification." Journal of Clinical Microbiology 55, no. 2 (November 23, 2016): 431–41. http://dx.doi.org/10.1128/jcm.02027-16.
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ABSTRACTHepatitis D virus (HDV) is responsible for fulminant hepatitis and liver failure and accelerates evolution toward cirrhosis and hepatocellular carcinoma in hepatitis B virus (HBV)-infected patients. To date, treatment relies upon long-term administration of pegylated alpha-interferon with a sustained virological response in 30% of the patients. Very recently, new, promising anti-HDV therapies have been developed and are already being used in clinical trials. HDV RNA viral load (HDVL) monitoring must be an integral part of the management of the infected patients. However, HDV genus is characterized by a high genetic variability into eight genotypes (HDV-1 to -8), and most available in-house or commercial assays are useful for only a limited subset of genotypes. Results of a comparison of the performance of a new kit for HDVL quantification with the consensus in-house assay of the French National Reference Laboratory for HDV developed in 2005 are reported here. A total of 611 clinical samples of all HDV genotypes with various HDVL values, including several consecutive samples over several years from 36 patients, were studied. A specificity, sensitivity, and reproducibility evaluation was conducted using HDV-positive clinical samples, hepatitis A, B, C and E (HAV, HBV, HCV, and HEV, respectively) and HIV mono-infected samples, and the WHO HDV RNA international standard. Overall results were strictly comparable between the two assays (median difference, 0.07 log IU/ml), with high diagnosis precision and capacity. In summary, this new kit showed high performance in detection/quantification of HDVL, regardless of the genotype of the infecting strain used, and seems to be a suitable tool for patient management.
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Torabi, Sina, and Mattias Wahde. "Fuel-Efficient Driving Strategies for Heavy-Duty Vehicles: A Platooning Approach Based on Speed Profile Optimization." Journal of Advanced Transportation 2018 (September 26, 2018): 1–12. http://dx.doi.org/10.1155/2018/4290763.
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A method for reducing the fuel consumption of a platoon of heavy-duty vehicles (HDVs) is described and evaluated in simulations for homogeneous and heterogeneous platoons. The method, which is based on speed profile optimization and is referred to as P-SPO, was applied to a set of road profiles of 10 km length, resulting in fuel reduction of 15.8% for a homogeneous platoon and between 16.8% and 17.4% for heterogeneous platoons of different mass configurations, relative to the combination of standard cruise control (for the lead vehicle) and adaptive cruise control (for the follower vehicle). In a direct comparison with MPC-based approaches, it was found that P-SPO outperforms the fuel savings of such methods by around 3 percentage points for the entire platoon, in similar settings. In P-SPO, unlike most common platooning approaches, each vehicle within the platoon receives its own optimized speed profile, thus eliminating the intervehicle distance control problem. Moreover, the P-SPO approach requires only a simple vehicle controller, rather than the two-layer control architecture used in MPC-based approaches.
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Tanco, Martín, Matías Aresti, Julio Villalobos, Diego Moratorio, Daniel Jurburg, and Jose Holguin-Veras. "Assessment of the effectiveness of a fuel additive to reduce fuel consumption of HDVs highlights the importance of verification programs." Energy 189 (December 2019): 116269. http://dx.doi.org/10.1016/j.energy.2019.116269.
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Peters, Ralf, Janos Lucian Breuer, Maximilian Decker, Thomas Grube, Martin Robinius, Remzi Can Samsun, and Detlef Stolten. "Future Power Train Solutions for Long-Haul Trucks." Sustainability 13, no. 4 (February 19, 2021): 2225. http://dx.doi.org/10.3390/su13042225.
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Achieving the CO2 reduction targets for 2050 requires extensive measures being undertaken in all sectors. In contrast to energy generation, the transport sector has not yet been able to achieve a substantive reduction in CO2 emissions. Measures for the ever more pressing reduction in CO2 emissions from transportation include the increased use of electric vehicles powered by batteries or fuel cells. The use of fuel cells requires the production of hydrogen and the establishment of a corresponding hydrogen production system and associated infrastructure. Synthetic fuels made using carbon dioxide and sustainably-produced hydrogen can be used in the existing infrastructure and will reach the extant vehicle fleet in the medium term. All three options require a major expansion of the generation capacities for renewable electricity. Moreover, various options for road freight transport with light duty vehicles (LDVs) and heavy duty vehicles (HDVs) are analyzed and compared. In addition to efficiency throughout the entire value chain, well-to-wheel efficiency and also other aspects play an important role in this comparison. These include: (a) the possibility of large-scale energy storage in the sense of so-called ‘sector coupling’, which is offered only by hydrogen and synthetic energy sources; (b) the use of the existing fueling station infrastructure and the applicability of the new technology on the existing fleet; (c) fulfilling the power and range requirements of the long-distance road transport.
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Wu, Luolin, Ming Chang, Xuemei Wang, Jian Hang, Jinpu Zhang, Liqing Wu, and Min Shao. "Development of the Real-time On-road Emission (ROE v1.0) model for street-scale air quality modeling based on dynamic traffic big data." Geoscientific Model Development 13, no. 1 (January 3, 2020): 23–40. http://dx.doi.org/10.5194/gmd-13-23-2020.
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Abstract. Rapid urbanization in China has led to heavy traffic flows in street networks within cities, especially in eastern China, the economically developed region. This has increased the risk of exposure to vehicle-related pollutants. To evaluate the impact of vehicle emissions and provide an on-road emission inventory with higher spatiotemporal resolution for street-network air quality models, in this study, we developed the Real-time On-road Emission (ROE v1.0) model to calculate street-scale on-road hot emissions by using real-time big data for traffic provided by the Gaode Map navigation application. This Python-based model obtains street-scale traffic data from the map application programming interface (API), which are open-access and updated every minute for each road segment. The results of application of the model to Guangzhou, one of the three major cities in China, showed on-road vehicle emissions of carbon monoxide (CO), nitrogen oxide (NOx), hydrocarbons (HCs), PM2.5, and PM10 to be 35.22×104, 12.05×104, 4.10×104, 0.49×104, and 0.55×104 Mg yr−1, respectively. The spatial distribution reveals that the emission hotspots are located in some highway-intensive areas and suburban town centers. Emission contribution shows that the dominant contributors are light-duty vehicles (LDVs) and heavy-duty vehicles (HDVs) in urban areas and LDVs and heavy-duty trucks (HDTs) in suburban areas, indicating that the traffic control policies regarding trucks in urban areas are effective. In this study, the Model of Urban Network of Intersecting Canyons and Highways (MUNICH) was applied to investigate the impact of traffic volume change on street-scale photochemistry in the urban areas by using the on-road emission results from the ROE model. The modeling results indicate that the daytime NOx concentrations on national holidays are 26.5 % and 9.1 % lower than those on normal weekdays and normal weekends, respectively. Conversely, the national holiday O3 concentrations exceed normal weekday and normal weekend amounts by 13.9 % and 10.6 %, respectively, owing to changes in the ratio of emission of volatile organic compounds (VOCs) and NOx. Thus, not only the on-road emissions but also other emissions should be controlled in order to improve the air quality in Guangzhou. More significantly, the newly developed ROE model may provide promising and effective methodologies for analyzing real-time street-level traffic emissions and high-resolution air quality assessment for more typical cities or urban districts.
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Brito, J., L. V. Rizzo, P. Herckes, P. C. Vasconcellos, S. E. S. Caumo, A. Fornaro, R. Y. Ynoue, P. Artaxo, and M. F. Andrade. "Physical-chemical characterization of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area." Atmospheric Chemistry and Physics Discussions 13, no. 8 (August 9, 2013): 20839–83. http://dx.doi.org/10.5194/acpd-13-20839-2013.
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Abstract. The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterize the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are Light Duty Vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by Heavy Duty Vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM2.5 concentration was on average 52 μg m−3, with the largest contribution of Organic Mass (OM, 42%), followed by Elemental Carbon (EC, 17%) and Crustal elements (13%). Sulphate accounted for 7% of PM2.5 and the sum of other trace elements was 10%. In the RA tunnel, PM2.5 was on average 233 μg m−3, mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1% and 1%, respectively. The average OC:EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC:EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel fuelled HDVs. Besides bulk carbonaceous aerosol measurement, Polycyclic Aromatic Hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m−3 and 45 ± 9 ng m−3 in the RA and JQ tunnel, respectively. In the JQ tunnel, Benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m−3 (0.02–0.1‰ of PM2.5) in the JQ tunnel whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m−3 (0.004–0.02‰ of PM2.5), indicating an important relative contribution of LDVs emission to atmospheric BaP. Real-time measurements performed in both tunnels provided aerosol size distributions and optical properties. The average particle count yielded 73 000 cm−3 in the JQ tunnel and 366 000 cm−3 in the RA tunnel, with an average diameter of 48 nm in the former and 39 nm in the latter. Aerosol single scattering albedo, calculated from scattering and absorption observations in the JQ tunnel, showed a minimum value of 0.4 at the peak of the morning rush hour, reached 0.6 around noon and stabilized at 0.5 in the afternoon and evening. Such single scattering albedo range is close to other tunnel studies results, despite significant biofuel usage. Given the exceedingly high Black Carbon loadings in the RA tunnel, real time light absorption measurements were possible only in the JQ tunnel. Nevertheless, using EC measured from the filters a single scattering albedo of 0.32 for the RA tunnel has been estimated. The results presented here characterize particulate matter emitted from nearly 1 million vehicles fuelled with a considerable amount of biofuel, providing an unique experimental site worldwide.
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Brito, J., L. V. Rizzo, P. Herckes, P. C. Vasconcellos, S. E. S. Caumo, A. Fornaro, R. Y. Ynoue, P. Artaxo, and M. F. Andrade. "Physical–chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area." Atmospheric Chemistry and Physics 13, no. 24 (December 17, 2013): 12199–213. http://dx.doi.org/10.5194/acp-13-12199-2013.
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Abstract. The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by heavy duty vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM2.5 concentration was on average 52 μg m−3, with the largest contribution of organic mass (OM, 42%), followed by elemental carbon (EC, 17%) and crustal elements (13%). Sulphate accounted for 7% of PM2.5 and the sum of other trace elements was 10%. In the RA tunnel, PM2.5 was on average 233 μg m−3, mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1%, and 1%, respectively. The average OC : EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC : EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel-fuelled HDVs. Besides bulk carbonaceous aerosol measurement, polycyclic aromatic hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m−3 and 45 ± 9 ng m−3 in the RA and JQ tunnel, respectively. In the JQ tunnel, benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m−3 (0.02–0.1‰ of PM2.5) whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m−3 (0.004–0. 02‰ of PM2.5), indicating an important relative contribution of LDVs emission to atmospheric BaP. Real-time measurements performed in both tunnels provided aerosol size distributions and optical properties. The average particle count yielded 73 000 cm−3 in the JQ tunnel and 366 000 cm−3 in the RA tunnel, with an average diameter of 48 nm in the former and 39 nm in the latter. Aerosol single scattering albedo, calculated from scattering and absorption observations in the JQ tunnel, indicates a value of 0.5 associated with LDVs. Such single scattering albedo is 20–50% higher than observed in previous tunnel studies, possibly as a result of the large biofuel usage. Given the exceedingly high equivalent black carbon loadings in the RA tunnel, real time light absorption measurements were possible only in the JQ tunnel. Nevertheless, using EC measured from the filters, a single scattering albedo of 0.31 for the RA tunnel has been estimated. The results presented here characterise particulate matter emitted from nearly 1 million vehicles fuelled with a considerable amount of biofuel, providing a unique experimental site worldwide.
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Wang, Lijuan, Guimin Zhang, Hui Lin, Liang Liang, and Zheng Niu. "Estimation of leaf area index using an angular vegetation index based on in situ measurements and CHRIS/PROBA data." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 20, 2016): 121–28. http://dx.doi.org/10.5194/isprsarchives-xli-b7-121-2016.
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The Normalized Difference Vegetation Index (NDVI) is widely used for Leaf Area Index (LAI) estimation. It is well documented that the NDVI is extremely subject to the saturation problem when LAI reaches a high value. A new multi-angular vegetation index, the Hotspot-darkspot Difference Vegetation Index (HDVI) is proposed to estimate the high density LAI. The HDVI, defined as the difference between the hot and dark spot NDVI, relative to the dark spot NDVI, was proposed based on the Analytical two-layer Canopy Reflectance Model (ACRM) model outputs. This index is validated using both in situ experimental data in wheat and data from the multi-angular optical Compact High-Resolution Imaging Spectrometer (CHRIS) satellite. Both indices, the Hotspot-Darkspot Index (HDS) and the NDVI were also selected to analyze the relationship with LAI, and were compared with new index HDVI. The results show that HDVI is an appropriate proxy of LAI with higher determination coefficients (R2) for both the data from the in situ experiment (R2=0.7342, RMSE=0.0205) and the CHRIS data (R2=0.7749, RMSE=0.1013). Our results demonstrate that HDVI can make better the occurrence of saturation limits with the information of multi-angular observation, and is more appropriate for estimating LAI than either HDS or NDVI at high LAI values. Although the new index needs further evaluation, it also has the potential under the condition of dense canopies. It provides the effective improvement to the NDVI and other vegetation indices that are based on the red and NIR spectral bands.
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Wang, Lijuan, Guimin Zhang, Hui Lin, Liang Liang, and Zheng Niu. "Estimation of leaf area index using an angular vegetation index based on in situ measurements and CHRIS/PROBA data." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 20, 2016): 121–28. http://dx.doi.org/10.5194/isprs-archives-xli-b7-121-2016.
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The Normalized Difference Vegetation Index (NDVI) is widely used for Leaf Area Index (LAI) estimation. It is well documented that the NDVI is extremely subject to the saturation problem when LAI reaches a high value. A new multi-angular vegetation index, the Hotspot-darkspot Difference Vegetation Index (HDVI) is proposed to estimate the high density LAI. The HDVI, defined as the difference between the hot and dark spot NDVI, relative to the dark spot NDVI, was proposed based on the Analytical two-layer Canopy Reflectance Model (ACRM) model outputs. This index is validated using both in situ experimental data in wheat and data from the multi-angular optical Compact High-Resolution Imaging Spectrometer (CHRIS) satellite. Both indices, the Hotspot-Darkspot Index (HDS) and the NDVI were also selected to analyze the relationship with LAI, and were compared with new index HDVI. The results show that HDVI is an appropriate proxy of LAI with higher determination coefficients (R2) for both the data from the in situ experiment (R2=0.7342, RMSE=0.0205) and the CHRIS data (R2=0.7749, RMSE=0.1013). Our results demonstrate that HDVI can make better the occurrence of saturation limits with the information of multi-angular observation, and is more appropriate for estimating LAI than either HDS or NDVI at high LAI values. Although the new index needs further evaluation, it also has the potential under the condition of dense canopies. It provides the effective improvement to the NDVI and other vegetation indices that are based on the red and NIR spectral bands.
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Rahman, S. M. Ashrafur, I. M. Rizwanul Fattah, Hwai Chyuan Ong, Fajle Rabbi Ashik, Mohammad Mahmudul Hassan, Md Tausif Murshed, Md Ashraful Imran, et al. "State-of-the-Art of Establishing Test Procedures for Real Driving Gaseous Emissions from Light- and Heavy-Duty Vehicles." Energies 14, no. 14 (July 12, 2021): 4195. http://dx.doi.org/10.3390/en14144195.
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Air pollution caused by vehicle emissions has raised serious public health concerns. Vehicle emissions generally depend on many factors, such as the nature of the vehicle, driving style, traffic conditions, emission control technologies, and operational conditions. Concerns about the certification cycles used by various regulatory authorities are growing due to the difference in emission during certification procedure and Real Driving Emissions (RDE). Under laboratory conditions, certification tests are performed in a ‘chassis dynamometer’ for light-duty vehicles (LDVs) and an ‘engine dynamometer’ for heavy-duty vehicles (HDVs). As a result, the test drive cycles used to measure the automotive emissions do not correctly reflect the vehicle’s real-world driving pattern. Consequently, the RDE regulation is being phased in to reduce the disparity between type approval and vehicle’s real-world emissions. According to this review, different variables such as traffic signals, driving dynamics, congestions, altitude, ambient temperature, and so on have a major influence on actual driving pollution. Aside from that, cold-start and hot-start have been shown to have an effect on on-road pollution. Contrary to common opinion, new technology such as start-stop systems boost automotive emissions rather than decreasing them owing to unfavourable conditions from the point of view of exhaust emissions and exhaust after-treatment systems. In addition, the driving dynamics are not represented in the current laboratory-based test procedures. As a result, it is critical to establish an on-road testing protocol to obtain a true representation of vehicular emissions and reduce emissions to a standard level. The incorporation of RDE clauses into certification procedures would have a positive impact on global air quality.
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Lee, J. H., K. W. Bang, Y. J. Cho, and S. J. Joh. "The hydrodynamic filter separator for removal of urban storm runoff." Water Science and Technology 53, no. 7 (March 1, 2006): 243–52. http://dx.doi.org/10.2166/wst.2006.229.
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The majority of storm runoff pollution is trapped in particles smaller than 100 μm in diameter. Solid particles smaller than 100 μm in diameter are not easily separated by conventional types of hydrodynamic separator, and remain in suspension in overflow. To overcome this problem, a HDFS (hydrodynamic filter separator) has been developed for treatment of the microparticles in urban storm runoff. We conducted a laboratory scale study on treatable potential of microparticles using HDFS that combined HDS with perlite filter. To determine the efficiency for various operation conditions, a series of experiments was performed with different solids concentrations and surface loading rate. The operation ranges of surface loading rates were 100 to 2,800 m3/m2/day, and influent solids concentrations were varied from 800 to 1,900 mg/L. Also, the particle size distribution was monitored to investigate the effects of surface loading rates on the particle size. Results indicated that the HDFS-Inside type showed greater efficiency at solids separation than the other type.
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Wang, M., T. Zhu, J. Zheng, R. Y. Zhang, S. Q. Zhang, X. X. Xie, Y. Q. Han, and Y. Li. "Use of a mobile laboratory to evaluate changes in on-road air pollutants during the Beijing 2008 Summer Olympics." Atmospheric Chemistry and Physics 9, no. 21 (November 3, 2009): 8247–63. http://dx.doi.org/10.5194/acp-9-8247-2009.
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Abstract. China implemented systematic air pollution control measures during the 2008 Beijing Summer Olympics and Paralympics to improve air quality. This study used a versatile mobile laboratory to conduct in situ monitoring of on-road air pollutants along Beijing's Fourth Ring Road on 31 selected days before, during, and after the Olympics air pollution control period. A suite of instruments with response times of less than 30 s was used to measure temporal and spatial variations in traffic-related air pollutants, including NOx, CO, PM1.0 surface area (S(PM1)), black carbon (BC), and benzene, toluene, the sum of ethylbenzene, and m-, p-, and o-xylene (BTEX). During the Olympics (8–23 August, 2008), on-road air pollutant concentrations decreased significantly, by up to 54% for CO, 41% for NOx, 70% for SO2, 66% for BTEX, 12% for BC, and 18% for SPM1, compared with the pre-control period (before 20 July). Concentrations increased again after the control period ended (after 20 September), with average increases of 33% for CO, 42% for NOx, 60% for SO2, 40% for BTEX, 26% for BC, and 37% for S(PM1), relative to the control period. Variations in pollutants concentrations were correlated with changes in traffic speed and the number and types of vehicles on the road. Throughout the measurement periods, the concentrations of NOx, CO, and BTEX varied markedly with the numbers of light- and medium-duty vehicles (LDVs and MDVs, respectively) on the road. Only after 8 August was a noticeable relationship found between BC and S(PM1) and the number of heavy-duty vehicles (HDVs). Additionally, BC and S(PM1) showed a strong correlation with SO2 before the Olympics, indicating possible industrial sources from local emissions as well as regional transport activities in the Beijing area. Such factors were identified in measurements conducted on 6 August in an area southwest of Beijing. The ratio of benzene to toluene, a good indicator of traffic emissions, shifted suddenly from about 0.26 before the Olympics to approximately 0.48 after the Olympics began. This finding suggests that regulations on traffic volume and restrictions on the use of painting solvents were effective after the Olympics began. This study demonstrated the effectiveness of air pollution control measures and identified local and regional pollution sources within and surrounding the city of Beijing. The findings will be invaluable for emission inventory evaluations and model verifications.
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Wang, M., T. Zhu, J. Zheng, R. Y. Zhang, S. Q. Zhang, X. X. Xie, Y. Q. Han, and Y. Li. "Use of a mobile laboratory to evaluate changes in on-road air pollutants during the Beijing 2008 Summer Olympics." Atmospheric Chemistry and Physics Discussions 9, no. 3 (June 5, 2009): 12857–98. http://dx.doi.org/10.5194/acpd-9-12857-2009.
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Abstract. China implemented systematic air pollution control measures during the 2008 Beijing Summer Olympics and Paralympics to improve air quality. This study used an innovative mobile laboratory to conduct in situ monitoring of on-road air pollutants along Beijing's 4th Ring Road on 31 selected days before, during, and after the Olympics air pollution control period. A suite of instruments with response times of less than 30 s was used to measure temporal and spatial variations in traffic-related air pollutants, including NOx, CO, PM1.0 surface area (SPM1), black carbon (BC), and benzene, toluene, ethylbenzene, and m-, p-, and o-xylene (BTEX). During the Olympics (8–23 August 2008), on-road air pollutant concentrations decreased significantly by up to 54% for CO, 41% for NOx, 70% for SO2, 66% for BTEX, 12% for BC, and 18% for SPM1 compared to the pre-control period (before 20 July). Concentrations increased again after the control period ended (after 20 September), with average increases of 33% for CO, 42% for NOx, 60% for SO2, 40% for BTEX, 26% for BC, and 37% for SPM1. Variations in pollutants concentrations were correlated with changes in traffic speed and the number and types of vehicles on the road. Throughout the measurement periods, the concentrations of NOx, CO, and BTEX varied markedly with the numbers of light- and medium-duty vehicles (LDVs and MDVs, respectively) on the road. Only after 8 August was a noticeable relationship between BC and SPM1 and the number of heavy-duty vehicles (HDVs) found. Additionally, BC and SPM1 showed a strong correlation with SO2 before the Olympics, indicating possible industrial sources from local emissions as well as regional transport activities in the Beijing area. Such factors were identified in measurements conducted on 6 August in an area southwest of Beijing. The ratio of benzene to toluene, a good indicator of traffic emissions, shifted suddenly from about 0.26 before the Olympics to approximately 0.48 after the Olympics began. This finding suggests that regulations on traffic volume and restrictions on the use of painting solvents were effective after the Olympics began. This study demonstrated the effectiveness of air pollution control measures and identified local and regional pollution sources within and surrounding the city of Beijing. The findings will be invaluable for emission inventory evaluations and model verifications.
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Wang, F., M. Ketzel, T. Ellermann, P. Wåhlin, S. S. Jensen, D. Fang, and A. Massling. "Particle number, particle mass and NO<sub>x</sub> emission factors at a highway and an urban street in Copenhagen." Atmospheric Chemistry and Physics 10, no. 6 (March 24, 2010): 2745–64. http://dx.doi.org/10.5194/acp-10-2745-2010.
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Abstract. This paper presents measurements of traffic-generated gas and particle pollution at two sites, one near a major highway and one near a busy urban street in Copenhagen, Denmark. Both sites were equipped for a 4-week period with a set of two measurement stations, one close to the kerbside and one background station. Measurements were carried out from March to April~2008, investigating NOx concentrations, submicrometer particle number size distribution (size range 10–700 nm), particle mass (PM2.5, PM10), and meteorological parameters. In this study we also estimate the emission factors for NOx, particle number and particle mass using measured traffic volume and dilution rate calculated by the Operational Street Pollution Model (WinOSPM). The mean concentrations of most of the measured pollutants are similar for the highway and the urban kerbside stations due to similar traffic density. The average concentrations of NOx are 142 μg m−3 and 136 μg m−3 for the highway and the urban kerbside stations, respectively. These values are about 5 times higher compared to the corresponding background values. The average particle number concentration is 24 900 particles cm−3 and 27 100 particles cm−3 for the highway and the urban kerbside stations, respectively, and these values exceed those measured at the background stations by a factor of 3 to 5. The temporal variation of the traffic contribution (difference of kerbside and background concentrations) is analysed for NOx, particle number and mass, and it follows the traffic pattern at the urban and the highway sites. Emission factors for particle number are found to be quite similar at both sites, (215±5) 1012 particles veh−1 km−1 for the highway and (187±3) 1012 particles veh−1 km−1 for the urban site. Heavy duty vehicles (HDVs) are found to emit about 20 times more particles than light duty vehicles (LDVs), which is in good agreement with other published studies. Emission factors are also determined for individual particle modes identified in the size spectra. Average fleet emission factors for PM2.5 at the highway and the urban site are 29 mg veh−1 km−1 and 46 mg veh−1 km−1, respectively. The estimated particle number and size spectra emission factors will provide valuable input for air quality and particle dispersion modelling near highways and in urban areas.
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Popov, Evgeny, and Yury Shornikov. "LISMA_HDS language for modeling heterogeneous dynamic systems." Analysis and data processing systems, no. 1 (March 26, 2021): 103–22. http://dx.doi.org/10.17212/2782-2001-2021-1-103-122.
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Heterogeneous dynamic systems (HDS) simultaneously describe processes of different physical nature. Systems of this kind are typical for numerous applications. HDSs are characterized by the following features. They are often multimode or hybrid systems. In general, their modes are defined as initial value problems (Cauchy problems) for implicit differential-algebraic systems of equations. Due to the presence of heterogeneous dynamic components or processes evolving in both time and space, the dimension of the complete system of equations may be pretty high. In some cases, the system of equations has an internal structure, for instance, the differential-algebraic system of equations approximating a partial differential equation by the method of lines. An original huge system of equations can then be algorithmically rewritten in a compact form. Moreover, heterogeneous hybrid dynamical systems can generate events of qualitatively different types. Therefore one has to use different numerical event detection algorithms. Nowadays, HDSs are modeled and simulated in computer environments. The modeling languages widely used by engineers do not allow them to fully specify all the properties of the systems of this class. For instance, they do not include event typing constructs. That is why a declarative general-purpose modeling language named LISMA_HDS has been developed for the computer-aided modeling and ISMA simulation environment. The language takes into account all of the characteristic features of HDSs. It includes constructs for plain or algorithmic declaration of model constants, initial value problems for explicit differential-algebraic systems of equations, and initial guesses for variables. It also allows researchers to define explicit time events, modes and transitions between them upon the occurrence of events of different types, to use macros and implement event control. LISMA_HDS is defined by a generative grammar in an extended Backus-Naur form and semantic constraints. It is proved that the grammar belongs to the LL(2) subclass of context-free grammars.
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Mare, Rosario, Huining Da, Massimo Fresta, Donato Cosco, and Vibhudutta Awasthi. "Anchoring Property of a Novel Hydrophilic Lipopolymer, HDAS-SHP, Post-Inserted in Preformed Liposomes." Nanomaterials 9, no. 9 (August 21, 2019): 1185. http://dx.doi.org/10.3390/nano9091185.
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Polyethylene glycol (PEG)-phospholipids in long-circulating liposomes cause non-specific immune reactions; mainly attributable to negatively-charged phosphoryl s at the interface of PEG and phospholipid. We investigated a novel lipopolymer, by which a superhydrophilic polymer (SHP) is conjugated to a non-phospholipid N1-(2-aminoethyl)-N4-hexadecyl-2-tetradecylsuccinamide (HDAS). The modification of preformed liposomes HDAS-SHP, HDAS-PEG2000, and DSPE-PEG2000 were performed by post-insertion techniques. The efficiency of post-insertion and desorption rates, from the liposome surface, were determined. HDAS-SHP micelles showed highly positive zeta potential (+28.4 mV); zeta potentials of DSPE-PEG2000 and HDAS-PEG2000 micelles were −34.4 mV, and −3.7 mV, respectively. Critical micelle concentration predicted amphiphilicity of HDAS-SHP (CMC 2.58 µM) as close to that of DSPE-PEG2000 (CMC 2.44 µM). Both HDAS-SHP and HDAS-PEG2000 post-inserted with comparable efficiency (79%, and 73%, respectively), but noticeably lower than DSPE-PEG2000 (90%). The desorption rate of HDAS-SHP was close to that of DSPE-PEG2000 (0.53%/h, and 0.45%/h, respectively); the desorption rate for HDAS-PEG2000 was slightly more at 0.67%/h. Compared to plain liposomes, both HDAS-SHP- and DSPE-PEG2000-liposomes showed significant leakage of encapsulated Na-fluorescein isothiocyanate (FITC) upon incubation with serum. At the same time, both modified liposomes were found to suppress serum levels of the complement proteins, Bb and C4d. We infer that HDAS-SHP is a viable alternative to commonly-used PEG-phospholipid derivatives for stealth purposes.
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VARELLA, ANDREA YASBEK MONTEIRO, JULIANA MARIA FUKUDA, MARCELO PASSOS TEIVELIS, JOSÉ RIBAS MILANEZ DE CAMPOS, PAULO KAUFFMAN, GABRIEL GRIZZO CUCATO, PEDRO PUECH-LEÃO, and NELSON WOLOSKER. "Translation and validation of Hyperhidrosis Disease Severity Scale." Revista da Associação Médica Brasileira 62, no. 9 (December 2016): 843–47. http://dx.doi.org/10.1590/1806-9282.62.09.843.
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SUMMARY Introduction The evaluation of patients with hyperhidrosis (HH) can be accomplished, among other ways, through questionnaires and scales. The Hyperhidrosis Disease Severity Scale (HDSS) has been used as a simple and quick tool to perform this evaluation. Although HDSS has been well established in several languages, it has not been translated into Portuguese, restricting its specific use for Brazilian patients. The aim of this study was to translate HDSS into Portuguese and validate it in a sample of Brazilian subjects. Method 290 Brazilian patients (69% women, with a mean age of 28.7±9.6 years and BMI 22.4±3.9 kg/m2) diagnosed with HH were evaluated using HDSS, Quality of Life Questionnaire (QLQ) and Sweating Evolution Questionnaire (SEQ) before and after a five-week oxybutynin treatment. Regarding validation, an association between HDSS results and two other questionnaires was performed. To analyze HDSS sensitivity, evaluation of effects pre- and post-treatment with oxybutynin was conducted. Furthermore, HDSS reproducibility was analyzed in a subsample in which the scale was applied again after 7 days of the first follow-up appointment. Results There was statistical correlation between HDSS and QLQ and between HDSS and SEQ before treatment and after 5 weeks. Additionally, HDSS was reproducible and sensitive to clinical changes after the treatment period. Conclusion The Portuguese version of HDSS has been validated and shown to be reproducible in a Brazilian sample. Therefore it can be used as a tool to improve medical assistance in patients with HH.
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Prasad, Suhanya V., Krzysztof Fiedoruk, Tamara Daniluk, Ewelina Piktel, and Robert Bucki. "Expression and Function of Host Defense Peptides at Inflammation Sites." International Journal of Molecular Sciences 21, no. 1 (December 22, 2019): 104. http://dx.doi.org/10.3390/ijms21010104.
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There is a growing interest in the complex role of host defense peptides (HDPs) in the pathophysiology of several immune-mediated inflammatory diseases. The physicochemical properties and selective interaction of HDPs with various receptors define their immunomodulatory effects. However, it is quite challenging to understand their function because some HDPs play opposing pro-inflammatory and anti-inflammatory roles, depending on their expression level within the site of inflammation. While it is known that HDPs maintain constitutive host protection against invading microorganisms, the inducible nature of HDPs in various cells and tissues is an important aspect of the molecular events of inflammation. This review outlines the biological functions and emerging roles of HDPs in different inflammatory conditions. We further discuss the current data on the clinical relevance of impaired HDPs expression in inflammation and selected diseases.