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Thakur, Shubham. "Power Generation Using SOFC and VOC treatment." International Research Journal on Advanced Science Hub 3, Special Issue ICARD-2021 3S (March 31, 2021): 200–204. http://dx.doi.org/10.47392/irjash.2021.092.
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Lee, Byung Uk. "Why Does the SARS-CoV-2 Delta VOC Spread So Rapidly? Universal Conditions for the Rapid Spread of Respiratory Viruses, Minimum Viral Loads for Viral Aerosol Generation, Effects of Vaccination on Viral Aerosol Generation, and Viral Aerosol Clouds." International Journal of Environmental Research and Public Health 18, no. 18 (September 17, 2021): 9804. http://dx.doi.org/10.3390/ijerph18189804.
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This study analyzes the reasons the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant of concern (VOC) spreads so rapidly. Novel topics such as universal conditions for the rapid spread of respiratory viruses, minimum viral loads for viral aerosol generation, effects of vaccination on viral aerosol generation, and viral aerosol clouds were studied. The analyses were based on experimental results and analytic model studies. Four universal conditions, namely asymptomatic host, high viral load, stability of viruses in air, and binding affinity of viruses to human cells, need to be satisfied for the rapid spread of respiratory viruses. SARS-CoV-2 and its variants such as the Alpha VOC and Delta VOC satisfy the four fundamental conditions. In addition, there is an original principle of aerosol generation of respiratory viruses. Assuming that the aerosol–droplet cutoff particle diameter for distinguishing potential aerosols from earthbound respiratory particles is 100 μm, the minimum viral load required in respiratory fluids to generate viral aerosols is ~106 copies mL−1, which is within the range of the reported viral loads in the Alpha VOC cases and the Delta VOC cases. The daily average viral loads of the Delta VOC in hosts have been reported to be between ~109 copies mL−1 and ~1010 copies mL−1 during the four days after symptom onset in 1848 cases of the Delta VOC infection. Owing to the high viral load, the SARS-CoV-2 Delta VOC has the potential to effectively spread through aerosols. COVID-19 vaccination can decrease aerosol transmission of the SARS-CoV-2 Alpha VOC by reducing the viral load. The viral load can explain the conundrum of viral aerosol spreading. The SARS-CoV-2 Delta VOC aerosol clouds have been assumed to be formed in restricted environments, resulting in a massive numbers of infected people in a very short period with a high spreading speed. Strong control methods against bioaerosols should be considered in this SARS-CoV-2 Delta VOC pandemic. Large-scale environmental monitoring campaigns of SARS-CoV-2 Delta VOC aerosols in public places in many countries are necessary, and these activities could contribute to controlling the coronavirus disease pandemic.
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Kayano, Taishi, and Hiroshi Nishiura. "Estimating the transmissibility of SARS-CoV-2 VOC 202012/01 in Japan using travel history information." Mathematical Biosciences and Engineering 19, no. 3 (2022): 2750–61. http://dx.doi.org/10.3934/mbe.2022125.
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<abstract> <p>Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has rapidly spread across the globe. The variant of concern (VOC) 202012/01 (B.1.1.7, also known as the alpha variant) bearing the N501Y mutation emerged in late 2020. VOC 202012/01 was more transmissible than existing SARS-CoV-2 variants and swiftly became dominant in many regions. More than 150 cases of VOC 202012/01 were reported in Japan by 26 February 2021. During the very early stage of introduction, only a subset arose from domestic transmission. If the reproduction number <italic>R</italic> (i.e., the average number of secondary transmission events caused by a single primary case) is greater than 1, the corresponding proportion should converge to 1 in a short period of time, and thus it is critical to understand the transmissibility of VOC 202012/01 based on travel history information. The present study aimed to estimate <italic>R</italic> of VOC 202012/01 using overseas travel history information. A mathematical model was developed to capture the relationship between travel history and <italic>R</italic>. We obtained travel history data for each confirmed case of VOC 202012/01 infection from 26 December 2020 to 26 February 2021. Maximum likelihood estimation was used to estimate <italic>R</italic>, accounting for right censoring during real-time estimation. In the baseline scenario, <italic>R</italic> was estimated at 2.11 (95% confidence interval: 1.63, 2.94). By 26 February 2021, an average of nine generations had elapsed since the first imported case. If the generation time of VOC 202012/01 was assumed to be longer, <italic>R</italic> was increased, consistent with estimates of <italic>R</italic> from case data. The estimated <italic>R</italic> of VOC 202012/01 in Japan exceeded 1 on 26 February 2021, suggesting that domestic transmission events caused a major epidemic. Moreover, because our estimate of <italic>R</italic> was dependent on generation time and ascertainment biases, continuous monitoring of contact tracing data is crucial to decipher the mechanisms of increased VOC 202012/01 transmissibility.</p> </abstract>
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Jenkin, M. E., S. M. Saunders, V. Wagner, and M. J. Pilling. "Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part B): tropospheric degradation of aromatic volatile organic compounds." Atmospheric Chemistry and Physics Discussions 2, no. 6 (November 7, 2002): 1905–38. http://dx.doi.org/10.5194/acpd-2-1905-2002.
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Abstract. Kinetic and mechanistic data relevant to the tropospheric degradation of aromatic volatile organic compounds (VOC) have been used to define a mechanism development protocol, which has been used to construct degradation schemes for 18 aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3). This is complementary to the treatment of 107 non-aromatic VOC, presented in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the degradation chemistry to first generation products via a number of competitive routes, and the further degradation of first and subsequent generation products. Emphasis is placed on describing where the treatment differs from that applied to the non-aromatic VOC. The protocol is based on work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Photochemical Ozone Creation Potentials (POCP) have been calculated for the 18 aromatic VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. These show distinct differences from POCP values calculated previously for the aromatics, using earlier versions of the MCM, and reasons for these differences are discussed.
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Jenkin, M. E., S. M. Saunders, V. Wagner, and M. J. Pilling. "Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part B): tropospheric degradation of aromatic volatile organic compounds." Atmospheric Chemistry and Physics 3, no. 1 (February 12, 2003): 181–93. http://dx.doi.org/10.5194/acp-3-181-2003.
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Abstract. Kinetic and mechanistic data relevant to the tropospheric degradation of aromatic volatile organic compounds (VOC) have been used to define a mechanism development protocol, which has been used to construct degradation schemes for 18 aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3). This is complementary to the treatment of 107 non-aromatic VOC, presented in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the degradation chemistry to first generation products via a number of competitive routes, and the further degradation of first and subsequent generation products. Emphasis is placed on describing where the treatment differs from that applied to the non-aromatic VOC. The protocol is based on work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Photochemical Ozone Creation Potentials (POCP) have been calculated for the 18 aromatic VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. These show distinct differences from POCP values calculated previously for the aromatics, using earlier versions of the MCM, and reasons for these differences are discussed.
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McCandless, Brian E. "CdTe Solar Cells: Processing Limits and Defect Chemistry Effects on Open Circuit Voltage." MRS Proceedings 1538 (2013): 249–60. http://dx.doi.org/10.1557/opl.2013.1017.
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ABSTRACTThe role of CdTe solar cell processing on the defect chemistry that limits open circuit voltage (VOC) is addressed in the thermochemical processing regimes commonly encountered in present-generation CdTe devices. The highest VOC is 0.91 V for a bulk CdTe crystal with ITO which is only marginally higher than VOC = 0.86 V obtained for polycrystalline CdTe films with CdS. Both fall ∼0.4 V short of the VOC expected for CdTe, having band gap EG = 1.5 eV. The present >16% efficient superstrate CdTe cell uses a process based on high-temperature, T > 500°C, CdTe growth on CdS, coupled with optimized methods for incorporating oxygen, sulfur, copper, and chloride species in the CdTe film. Pushing cell conversion efficiencies beyond 20% will require increasing VOC beyond 1V. However the present pathway of processing optimization will likely yield VOC and efficiency converging on 0.9 V and <20%, respectively.
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Tsigkou, Dimitra. "From Varieties of Capitalism to European Growth Models: towards a critical synthesis." Region & Periphery, no. 9 (July 29, 2020): 141. http://dx.doi.org/10.12681/rp.23788.
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The widespread belief that globalization would lead to the gradual convergence of advanced capitalist economies was challenged by the emergence of the Comparative Capitalism (CC) literature. Arguably the most influential approach within CC is the Varieties of Capitalism (VoC) model which argues that differences among advanced capitalist economies not only do not fade away but may be amplified due to the disparate comparative institutional advantages that various socioeconomic models may hold. VoC, nonetheless, was soon criticized -among others- for its binary ontological framework and heuristic shortcomings by the second generation CC. Contemporary writings within the third generation CC suggest a radical break from VoC as the focus should be, it is argued, on the demand, rather than the supply, side of the economy. This article posits that while the third generation CC has shifted attention to other institutional and policy fields, emphasizing essentially macroeconomic issues vis-à-vis economic policy reform, an epistemological rapprochement between the two main strands of CC could offer a more contextualized understanding of the different proposals put forward by the member states regarding the on-going Eurozone reform effort.
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Murin, L. I., J. Lennart Lindström, Bengt Gunnar Svensson, Vladimir P. Markevich, Anthony R. Peaker, and Charalamos A. Londos. "VOn (n≥3) Defects in Irradiated and Heat-Treated Silicon." Solid State Phenomena 108-109 (December 2005): 267–72. http://dx.doi.org/10.4028/www.scientific.net/ssp.108-109.267.
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Local vibrational mode (LVM) spectroscopy has been used to study the evolution of vacancy-oxygen-related defects (VOn) in the temperature range 300-700°C in carbon-lean Cz-Si samples irradiated with MeV electrons or neutrons. New experimental data confirming an attribution of the absorption bands at 910, 976 and 1105 cm-1 to the VO3 complex are obtained. In particular, a correlated generation of VO3 and the oxygen trimer is observed upon irradiation of Cz- Si crystals in the temperature range 300-400°C. Strong evidence for the assignment of the bands at 991 and 1014 cm-1 to a VO4 defect is presented. The lines are found to develop very efficiently in the VO2 containing materials enriched with the oxygen dimer. In such materials the formation of VO4 is enhanced due to occurrence of the reaction O2i+VO2 ⇒ VO4. Annealing of the VO3 and VO4 defects at T ≥ 550C °C is found to result in the appearance of new defects giving rise to a number of O-related LVM bands in the range 990-1110 cm-1. These bands are suggested to arise from VO5 and/or VO6 defects. Similar bands also appear upon the annihilation of oxygen-related thermal double donors at 650°C in Cz-Si crystals pre-annealed at 450°C.
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Dzhafarov, T. D., S. Aydin, and D. Oren. "Effect of Diffusion of I Group Metal (Ag) on Characteristics of Metal/Porous Silicon Sensors." Solid State Phenomena 131-133 (October 2007): 189–94. http://dx.doi.org/10.4028/www.scientific.net/ssp.131-133.189.
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Current-voltage characteristics of Schottky-type Ag/Porous Silicon (Ag/PS) structures in normal air, humid ambient and in different hydrogen-containing solutions (distilled water, freshwater, Black sea-water, ethanol ad methanol) have been investigated. Generation of the opencircuit voltage (Voc), short-circuit current (Jsc) up to 560 mV and 0.5mA/cm2, respectively, on placing Ag/PS structures in hydrogen-containing solutions was discovered. This phenomenon is reversible, i.e. placing and removal of Ag/PS structures cell from hydrogen-containing solutions is accompanied by response and recovery of the Voc and Jsc parameters. It is shown that the thermal annealing of the Ag/PS structure at 200oC for 10 min is accompanied by somewhat changes and stabilization of Voc and Jsc parameters of Ag/PS sensors. The possible mechanisms related with hydrogen-stimulated generation of voltage and diffusion-stimulated stabilization of the sensing parameters of Ag/PS Schottky-type structures is suggested. Data received in this work indicate on perspectivity of using Ag/PS structures as both the gas sensors and hydrogen cells.
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Gu, Xin, Kaitao Chen, Min Cai, Zhongyi Yin, Xingang Liu, and Xingru Li. "Study on the Fingerprint and Atmospheric Activity of Volatile Organic Compounds from Typical Industrial Emissions." International Journal of Environmental Research and Public Health 20, no. 4 (February 16, 2023): 3517. http://dx.doi.org/10.3390/ijerph20043517.
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China is prone to severe surface ozone pollution in summer, so it is very important to understand the source of volatile organic compounds (VOCs) to control ozone formation. In this work, the emission characteristics of 91 VOC components from the plastic products industry, packaging and printing industries, printing ink industry, furniture manufacturing and vehicle manufacturing industries were studied. The results show that there are significant differences between these sources, and for the plastic products industry, alkanes (48%) are the most abundant VOCs. The main emission species in the packaging and printing industry are OVOCs (36%) and alkanes (34%). The proportion of OVOCs in the printing ink (73%) and furniture manufacturing industries (49%) is dominated by VOC emissions; aromatic hydrocarbons (33%), alkanes (33%), and OVOCs (17%) are the main emission species in the vehicle manufacturing industry. At the same time, the ozone generation potential (OFP) and secondary organic aerosol formation potential (SOA) of anthropogenic VOC emissions were evaluated, and the top 10 contributors to OFP and SOA were identified. Toluene, o-xylene, and m-xylene had a significant tendency to form OFP or SOA. Then, a health risk assessment of VOC components was carried out. These data can supplement the existing VOC emission characteristics of anthropogenic emissions, thus enriching the research progress of VOC emission sources.
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De Jonge, Klaas, Arnold Janssens, and Jelle Laverge. "Performance assessment of demand controlled ventilation controls concerning indoor VOC exposure based on a dynamic VOC emission model." E3S Web of Conferences 111 (2019): 01051. http://dx.doi.org/10.1051/e3sconf/201911101051.
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The performance assessment of ventilation systems often focusses only on CO2 and humidity levels. The indoor Volatile Organic Compounds (VOC) emissions of building materials or other products is thereby overlooked. The new generation of ventilation systems, Demand Controlled Ventilation (DCV), are systems that do not supply the nominal airflow continuously but are controlled by CO2 or humidity sensors in order to save energy. This poses potential problems for exposure to VOCs. In this study, a dynamic VOC model, which takes into account changing temperature and humidity that was derived from literature, is implemented in a CONTAM model of the Belgian reference apartment. The impact of a DCV system on the indoor VOC levels is investigated. Results show that the use of a dynamic model is necessary compared to the previously used approximation of a constant emission. Furthermore, on a system level, the influence of the ventilation system control on the indoor VOC levels shows. The overall VOC concentration in the different rooms will be higher because of lowered ventilation rates. Especially in rooms that are often unoccupied during the day, the accumulation of VOCs shows. In the development of DCV system controls, the aspect of VOC exposure should not be overlooked to be able to benefit from both the energy savings and improved Indoor Air Quality (IAQ).
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Song, Jingnan, Ming Zhang, Tianyu Hao, Jun Yan, Lei Zhu, Guanqing Zhou, Rui Zeng, et al. "Design Rules of the Mixing Phase and Impacts on Device Performance in High-Efficiency Organic Photovoltaics." Research 2022 (July 27, 2022): 1–11. http://dx.doi.org/10.34133/2022/9817267.
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In nonfullerene acceptor- (NFA-) based solar cells, the exciton splitting takes place at both domain interface and donor/acceptor mixture, which brings in the state of mixing phase into focus. The energetics and morphology are key parameters dictating the charge generation, diffusion, and recombination. It is revealed that tailoringthe electronic properties of the mixing region by doping with larger-bandgap components could reduce the density of state but elevate the filling state level, leading to improved open-circuit voltage (VOC) and reduced recombination. The monomolecular and bimolecular recombinations are shown to be intercorrelated, which show a Gaussian-like relationship with VOC and linear relationship with short-circuit current density (JSC) and fill factor (FF). The kinetics of hole transfer and exciton diffusion scale with JSC similarly, indicating the carrier generation in mixing region and crystalline domain are equally important. From the morphology perspective, the crystalline order could contribute to VOC improvement, and the fibrillar structure strongly affects the FF. These observations highlight the importance of the mixing region and its connection with crystalline domains and point out the design rules to optimize the mixing phase structure, which is an effective approach to further improve device performance.
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Sparkenbaugh, Erica M., Camille Faes, Denis Noubouossie, Daniel K. Kirchhofer, András Gruber, Nigel S. Key, and Rafal Pawlinski. "FXIIa Differentially Regulates Thrombin Generation during Steady State and Vaso-Occlusive Crisis in Sickle Cell Mice." Blood 128, no. 22 (December 2, 2016): 162. http://dx.doi.org/10.1182/blood.v128.22.162.162.
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Abstract Sickle cell disease (SCD) is associated with chronic activation of coagulation. Previously, we demonstrated that inhibition of tissue factor (TF) attenuates thrombin generation (measured by plasma levels of thrombin-antithrombin complexes [TAT]) in a mouse model of SCD during steady state. Furthermore, we showed that neither inhibition of FXIIa-dependent activation of FXI (using 14E11 antibody) nor FXI deficiency reduces thrombin generation (TG) in sickle mice. In contrast, genetic deficiency of FXII or kininogen (HK) reduced plasma TAT levels. These data suggest that during steady state, FXIIa contributes to TG in sickle mice via activation of the kallikrein/HK pathway, but not FXI. In the present study, we further investigated the mechanisms of HK-induced TG at steady state, and increased TG observed during vaso-occlusive crisis (VOC). All experiments were performed using 4-5 month old Townes SS (sickle) and AA (control) mice. Kallikrein cleaves HK into HK fragments (HKFs) and bradykinin (BK). First, we investigated whether a BK-mediated increase in vascular permeability contributes to TG by exposing perivascular TF. This hypothesis was disproved by data demonstrating no difference in vascular permeability (measured by the extravasation of Evans blue in the heart, lung, liver and kidney) between AA (n=8) and SS (n=10) mice. HKFs were shown to induce leukocyte TF expression in vitro via binding to CD11b/CD18 (Mac-1). Therefore, we investigated whether Mac-1 inhibition affects TG in SS mice. AA and SS mice were treated with an inhibitory anti Mac-1 (M1/70) or IgG control antibody on days 0, 3 and 6 (i.p. 1 mg/kg) and TG was analyzed 1 day after the last injection. In the control group, SS mice demonstrated higher plasma TAT levels compared to AA mice (8.1±1.6 vs 4.2±0.6 ng/mL, n=10-11, p<0.05), but inhibition of Mac-1 significantly reduced plasma TAT levels in SS mice (4.6±0.7 ng/mL, n=11, p<0.05). These data suggest that HK might contribute to TG during steady state via Mac-1-dependent induction of monocyte TF. The steady state of SCD is interspersed with acute periods of VOC. Clinical data demonstrate that compared to the steady state, plasma levels of cell free DNA (cfDNA), activation of the contact system, and TG are further enhanced during VOC. To determine the mechanism of increased TG during VOC, we used the previously characterized mouse model of TNFα -induced VOC. Townes AA and SS mice were injected with recombinant TNFα (2 µg/g body weight) or the same volume of PBS, and plasma was collected 5 hours later. TNFα not only dramatically increased plasma levels of cfDNA in SS mice (14.78 ± 1.64 vs 679 ± 300 ng/mL; p<0.01), but also further increased plasma TAT levels compared to those observed in PBS-treated SS mice (2.9 fold, p<0.001, n=8). Importantly, there was a significant positive correlation between cfDNA and TAT in SS mice (r2 =0.65, p<0.001). Since cfDNA can activate FXII, we determined whether FXIIa-dependent activation of FXI contributes to TG during VOC. AA and SS mice received 14E11 or IgG control (4 mg/kg) 30 minutes before TNFα (2 μg/g) or PBS injection, and plasma TAT was assessed 5 hours later. Strikingly, 14E11 attenuated the increased TAT level in TNFα-treated SS mice, to the level observed in SS mice injected with PBS and IgG (IgG/SS/PBS: 9 ng/mL ± 1.8 vs. IgG/SS/TNF: 18.9 ± 3.6, p<0.001; 14E11/SS/TNF: 9.86 ± 0.72, p<0.05 vs. IgG/SS/TNF). We also determined if TF activity is required for the increased TG observed during VOC. Interestingly, inhibition of TF with an inhibitory 1H1 antibody (25 or 75 mg/kg injected i.p. 1 or 18 hours prior to TNFα, respectively) had no effect on the increased TG observed in TNFα treated SS mice. In aggregate, our data suggest that during the steady state of SCD, FXII-dependent TG is not FXI-dependent, but instead is mediated by a pathway involving HK, Mac-1 integrin and leukocyte TF. Furthermore, we propose that during VOC the massive release of cfDNA results in FXIIa-dependent FXI activation and enhances TG independently of TF. This study provides mechanistic insight into the initiators of TG in SCD. Moreover, it implicates FXIIa as a potential therapeutic target to reduce the prothrombotic state in SCD, during both steady state and VOC. Disclosures No relevant conflicts of interest to declare.
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Astakhov, O., V. Smirnov, R. Carius, B. E. Pieters, Yu Petrusenko, V. Borysenko, and F. Finger. "Dependence of open circuit voltage in a-Si:H and μc-Si:H solar cells on defect density in absorber layer varied by 2 MeV electron bombardment." Canadian Journal of Physics 92, no. 7/8 (July 2014): 905–8. http://dx.doi.org/10.1139/cjp-2013-0610.
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Theoretically predicted values of the open circuit voltage (VOC) for a-Si:H or μc-Si:H based solar cells are substantially higher than the values achieved in of state-of-the-art devices. Fundamentally, open circuit voltage is determined by generation-recombination kinetics, where recombination is often controlled by the defect density in the absorber layer of a solar cell. The latter aspect is the focus of the paper. The relation between the VOC and the bulk recombination in the absorber layer is addressed in experiment by varying the defect density. The absorber layer defect density (spin density, NS, monitored with ESR) in a-Si:H and μc-Si:H solar cells was varied over two orders of magnitude using a 2 MeV electron bombardment and successive stepwise annealing. The results of the electron bombardment experiment are analyzed with respect to the illumination intensity dependency of the VOC, measured for the same set of a-Si:H and μc-Si:H solar cells. We find that the VOC of a-Si:H solar cells is not limited by defects in the bulk of the absorber layer, even at relatively high defect density up to 3–5 × 1016 cm−3 and, therefore, other limiting mechanisms have to be identified to improve voltage in these devices. In contrast, μc-Si:H solar cells show nearly classical VOC–NS relation. The bulk defect density in μc-Si:H absorber layer is thus likely the key limiting factor for VOC in these devices at present status of material quality (NS of 3–7 × 1015 cm−3). Further optimization of μc-Si:H in terms of bulk defect density is highly relevant for VOC improvement in solar cells.
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Hao, Run, Song Xue, Hao Sun, Tao Yang, and Hailin Wang. "Emission Characteristics and the Environmental Impact of VOCs from Typical FRP Manufacture Industry." Atmosphere 13, no. 8 (August 11, 2022): 1274. http://dx.doi.org/10.3390/atmos13081274.
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The VOC emission characteristics of the typical fiber-reinforced plastics (FRPs) industry were studied for an assessment of the impact on the environment. The results showed that the VOC emissions of the typical FRP industry mainly come from grille, sheet, winding, molding, and pultrusion process links, including ketones, aldehydes, alcohols, and benzene series. The benzene series’ concentration represented by styrene was much higher than that of other species. The generation potential of ozone and the SOA in the typical production process were evaluated: in terms of ozone impact, the OFP values of the winding process were the highest, accounting for 65.9% of the total contribution. For the component contribution, the OFP contribution of the benzene series represented by styrene was far more than that of other VOC species, and the styrene mainly came from the use of unsaturated resin. In terms of the SOA impact, the pultrusion process contributed the most to the generation of SOA, accounting for 63.9% of the total SOA contribution. In terms of the component contribution, the contribution of SOA mainly came from the benzene series, accounting for nearly 95% of the total contribution of VOCs. Therefore, FRP enterprises should give priority to controlling the emission of the benzene series.
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Agarwal, Himanshu, and Tejashree M. Bhave. "Improved Open Circuit Voltage in Nano-Porous Silicon Based Hydrogen Fuel Cell." Nano Hybrids 5 (October 2013): 55–64. http://dx.doi.org/10.4028/www.scientific.net/nh.5.55.
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Hydrogen fuel cell generates electrical energy from the electrochemical reaction of hydrogen and oxygen with water vapor as a by-product. Polymer Exchange Membrane Fuel Cell (PEMFC) and Direct Methanol Fuel Cell (DMFC) which are normally utilized for portable applications are not only costly due to platinum electrodes, polymer membrane and supply of hydrogen or methanol as a fuel but also not integrable with silicon fabrication technology. Novel fuel cell based on nanoporous silicon (PS) as Metal/nanoPS/silicon Schottky type structure is under development and Open Circuit Voltage (Voc) upto 550 mV with Au as anode catalyst has been reported. Such fuel cell uses nanoporous silicon layer as proton exchange membrane. This type of structure is found to show humidity-voltaic effect i.e. generation of voltage in humid ambient. Humidity-stimulated voltage generation is facilitated by the hydrogen component of water present in the atmosphere. In the present work, our main objective was to improve Voc. We achieved Voc upto 1.118 V by restricting the pore size of nanoporous silicon to 4-5 nm and thickness of the Cu film to 100 nm. These results suggest that this type of fuel cell could be utilized to develop self-powered integrated circuit.
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Schick, B., U. Risse, and A. Kettrup. "Generation of test gases from volatile and semivolatile organic compounds (VOC/SVOC)." Fresenius' Journal of Analytical Chemistry 364, no. 8 (August 18, 1999): 709–13. http://dx.doi.org/10.1007/s002160051419.
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Gellert, Roland, and Wolfgang Horn. "Europäische Dämmstoffnormen der 2. Generation: Prüfmethoden zur Ermittlung flüchtiger organischer Komponenten (VOC)." Bauphysik 27, no. 4 (August 2005): 202–7. http://dx.doi.org/10.1002/bapi.200590053.
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Weingarten, M., T. Zweipfennig, A. Vescan, and H. Kalisch. "Low-Temperature Processed Hybrid Organic/Silicon Solar Cells with Power Conversion Efficiency up to 6.5%." MRS Proceedings 1771 (2015): 201–6. http://dx.doi.org/10.1557/opl.2015.650.
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ABSTRACTHybrid organic/silicon heterostructures have become of great interest for photovoltaic application due to their promising features (e.g. easy fabrication in a low-temperature process) for cost-effective photovoltaics. This work is focused on solar cells with a hybrid heterojunction between the polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) and n-doped monocrystalline silicon. As semi-transparent top contact, a thin (15 nm) Au layer was employed. Devices with different P3HT thicknesses were processed by spin-casting and compared with a reference Au/n-Si Schottky diode solar cell.The current density-voltage (J-V) measurements of the hybrid devices show a significant increase in open-circuit voltage (VOC) from 0.29 V up to 0.50 V for the best performing hybrid devices compared to the Schottky diode reference, while the short-circuit current density (JSC) does not change significantly. The increased VOC indicates that P3HT effectively reduces the reverse electron current into the gold contact. The wavelength-dependent JSC measurements show a decreased JSC in the wavelength range of P3HT absorption. This is related to the reduced JSC generation in silicon not being compensated by JSC generation in P3HT. It is concluded that the charge generation in P3HT is less efficient than in silicon.After a thermal annealing of the hybrid P3HT/silicon solar cells, we achieved power conversion efficiencies (PCE) (AM1.5 illumination) up to 6.5% with VOC of 0.52 V, JSC of 18.6 mA/cm² and a fill factor (FF) of 67%. This is more than twice the efficiency of the reference Schottky diode.
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Esparza-Isunza, Tristán, and Felipe López-Isunza. "Modeling the Transient VOC (toluene) Oxidation in a Packed-Bed Catalytic Reactor." International Journal of Chemical Reactor Engineering 14, no. 6 (December 1, 2016): 1177–85. http://dx.doi.org/10.1515/ijcre-2016-0026.
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Abstract A model is developed to study the transient behavior of a non-isothermal, non-adiabatic packed-bed reactor during VOC (toluene) oxidation with air on a mixed-oxide catalyst via Mars-van Krevelen kinetic scheme. The aim is to find a safe reactor design and operating conditions for VOC elimination, which has been collected in a battery of adsorption units from dilute VOC streams. Once each adsorption column is saturated, a non-isothermal desorption takes place, and the gas stream exiting the sequence of VOC desorption columns feeds continuously the catalytic reactor for VOC elimination. The reactor model describes a 2D two-phase system interacting through the gas-solid interphase, including convection and axial and radial dispersions of mass and heat. The simulations show that the gas flow velocity, and reactor and particle diameters, are key parameters to achieve a safe design, and that traveling reaction fronts in the packed-bed exist when a series of reversible stepwise changes are performed in the concentration and temperature at the feed, as a result of the transient balance between heat generation and heat elimination along the packed-bed. When comparing the perturbation in VOC concentration at the feed versus those in temperature, a large parametric sensitivity is observed for the latter case without the presence of multiple steady states. Due to the uncertainty in the values of the effective heat transport parameters, transient responses of different magnitude are observed for the same operating conditions when using heat transport parameter of different magnitude.
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Wesley Eckenfelder, W. "Alternative Strategies for Meeting Stringent Effluent Guidelines." Water Science and Technology 29, no. 8 (April 1, 1994): 1–7. http://dx.doi.org/10.2166/wst.1994.0370.
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Stringent effluent guidelines relating to volatile organic carbon (VOC), effluent toxicity and priority pollutants require a reappraisal of design criteria for wastewater treatment plants in the chemical and petrochemical industry. In the case of volatiles, the biodegradability of the VOC as well as the type of aeration equipment needs to be considered. High temperatures in covered aeration basins can create serious sludge settling problems. Priority pollutant removal requires careful consideration of adequate sludge age. Temperature is particularly significant in reducing priority pollutants to acceptable levels. The generation of non-degradable by-products, SMP, can create effluent toxicity problems. This may require tertiary treatment with activated carbon.
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Pérez-Sansalvador, Julio César, Noureddine Lakouari, Jesus Garcia-Diaz, and Saúl E. Pomares Hernández. "The Effect of Speed Humps on Instantaneous Traffic Emissions." Applied Sciences 10, no. 5 (February 27, 2020): 1592. http://dx.doi.org/10.3390/app10051592.
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Bad air quality due to free pollutants such as particulate matter (PM), carbon dioxide (CO 2 ), nitrogen oxides (NO x ) and volatile organic components (VOC) increases the risk of long- term health diseases. The impact of traffic-calming measures on air quality has been studied using specialized equipment at control sites or mounted on cars to monitor pollutants levels. However, this approach suffers from a large number of variables on the experiments such as vehicles types, number of monitored vehicles, driver’s behavior, traffic density, time of the day, elapsed monitoring time, road conditions and weather. In this work, we use a cellular automata and an instantaneous traffic emissions model to capture the effect of speed humps on traffic flow and on the generation of CO 2 , NO x , VOC and PM pollutants. This approach allows us to study and characterize the effect of many speed humps on a single lane. We found that speed humps significantly promote the generation of pollutants when the number of vehicles on a lane is low. Our results may provide insight into urban planning strategies to reduce the generation of traffic emissions and lower the risk of long-term health diseases.
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Li, Yi, Dan Deng, Rui Sun, Sihua Wu, LiLi Zhang, Ziqi Zhang, Jianqi Zhang, Jie Min, Guangjiu Zhao, and Zhixiang Wei. "Efficient charge generation and low open circuit voltage loss enable a PCE of 10.3% in small molecule donor and polymer acceptor organic solar cells." Journal of Materials Chemistry C 10, no. 7 (2022): 2639–47. http://dx.doi.org/10.1039/d1tc04428a.
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Two small donors with alkyl chains close to (Se-1) and away from (Se-2) the donor core were synthesized. Ordered molecular packing and an induced face-on packing by PJ1 enable an efficient charge generation and low Voc loss in the Se-2/PJ1 device.
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Dehimeche, Nafissa, Bruno Buatois, Nadia Bertin, and Michael Staudt. "Insights into the Intraspecific Variability of the above and Belowground Emissions of Volatile Organic Compounds in Tomato." Molecules 26, no. 1 (January 5, 2021): 237. http://dx.doi.org/10.3390/molecules26010237.
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The in-vivo monitoring of volatile organic compound (VOC) emissions is a potential non-invasive tool in plant protection, especially in greenhouse cultivation. We studied VOC production from above and belowground organs of the eight parents of the Multi-Parent Advanced Generation Intercross population (MAGIC) tomato population, which exhibits a high genetic variability, in order to obtain more insight into the variability of constitutive VOC emissions from tomato plants under stress-free conditions. Foliage emissions were composed of terpenes, the majority of which were also stored in the leaves. Foliage emissions were very low, partly light-dependent, and differed significantly among genotypes, both in quantity and quality. Soil with roots emitted VOCs at similar, though more variable, rates than foliage. Soil emissions were characterized by terpenes, oxygenated alkanes, and alkenes and phenolic compounds, only a few of which were found in root extracts at low concentrations. Correlation analyses revealed that several VOCs emitted from foliage or soil are jointly regulated and that above and belowground sources are partially interconnected. With respect to VOC monitoring in tomato crops, our results underline that genetic variability, light-dependent de-novo synthesis, and belowground sources are factors to be considered for successful use in crop monitoring.
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Shamieh, B., S. Obuchovsky, and G. L. Frey. "Spontaneous generation of interlayers in OPVs with silver cathodes: enhancing Voc and lifetime." Journal of Materials Chemistry C 4, no. 9 (2016): 1821–28. http://dx.doi.org/10.1039/c5tc04141d.
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Song, Mugeun, Kyunghoon Kim, Changmin Cho, and Daekeun Kim. "Reduction of Volatile Organic Compounds (VOCs) Emissions from Laundry Dry-Cleaning by an Integrated Treatment Process of Condensation and Adsorption." Processes 9, no. 9 (September 14, 2021): 1658. http://dx.doi.org/10.3390/pr9091658.
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Volatile organic compounds (VOCs) are intermittently emitted at high concentrations (tens of thousands of ppmv) from small-scale laundry shops in urban areas, affecting the urban atmospheric environment. In this study, we suggested integrating VOC treatment processes incorporating condensation and adsorption in series to remove VOCs released from small-scale laundry dryers (laundry weighing less than 30 kg). We designed two different processes depending on regeneration modes for adsorber beds; an open-circuit flow process and a closed-loop flow process in regeneration mode. Our VOC treatment processes enable sustainable operation via the regeneration of adsorbers on a regular basis. Before applying the VOC treatment processes, average concentration of total volatile organic compounds (TVOCs) was 4099 ppmv (12,000 ppmv of the peak concentration) during the drying operation. After applying our closed-loop flow process, TVOC concentration decreased to 58 ppmv, leading to 98.5% removal efficiency. We also verified the robustness of our process performance in a continuous operation (30 cycles) by using a process simulation program. Lastly, we observed that our integrated treatment process can contribute to reductions in ozone and secondary organic aerosol generation by 90.4% and 95.9%, respectively. We concluded that our integrated VOC treatment processes are applicable to small-scale laundry shops releasing high-concentration VOCs intermittently, and are beneficial to the atmospheric environment.
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Harry, Brian L., Yue Qiu, Ling Lu, Mara Couto-Rodriguez, Dorottya Nagy-Szakal, Niamh B. O’Hara, and Shi-Long Lu. "149. Extraction-free RT-PCR to Detect SARS-CoV-2 Variants of Concern." Open Forum Infectious Diseases 8, Supplement_1 (November 1, 2021): S89—S91. http://dx.doi.org/10.1093/ofid/ofab466.149.
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Abstract Background SARS-CoV-2 variants of concern (VOC) have challenged real-time reverse transcriptase polymerase chain reaction (RT-PCR) methods for the diagnosis of COVID-19. Methods The CDC 2019-Novel Coronavirus real-time RT-PCR panel was modified to create a single-plex extraction-free proxy RT-PCR assay, VOCFast™. This assay uses the nucleocapsid N1 as well as novel primer/probe pairs to target VOC mutations in the Orf1a and spike (S) genes. For analytical validation of VOCFast, synthetic controls for the Wuhan, alpha/B.1.1.7, beta/B.1.351, and gamma/P.1 strains were tested at various concentrations. Clinical validation was performed using patient anterior nares swab and saliva specimens collected in the Denver, CO area between Nov 2020 and Feb 2021 or in March 2021. Orthogonal next-generation sequencing (NGS) was also performed. Results Similar N1 quantification cycle (Cq) values corresponding to viral load were observed for all strains, suggesting that VOC mutations do not affect performance of the N1 primer/probe. Orf1a-mut and S1-mut primer/probes generated a stable high Cq value for the Wuhan strain. Conversely, Orf1a-mut Cq values were inversely correlated with viral load for all VOC. The S1-mut Cq was inversely correlated with viral load of the alpha strain, but did not reliably amplify beta/gamma VOC. The limit of detection was 8 copies/uL. The first set of COVID-19 patient specimens revealed no amplification using Orf1a-mut whereas 53% of specimens collected in Mar 2021 demonstrated amplification by Orf-1a. Orthogonal testing by the SARS-CoV-2 NGS Assay and COVID-DX software demonstrated that 12/12 alpha strains, 2/2 beta/gamma strains, and 33/33 Wuhan strains were correctly identified by VOCFast. Detection of VOC in clinical specimens and validation by NGS Conclusion The combination of the N1, Orf1a-mut, and S1-mut primers/probes in VOCFast can distinguish the Wuhan, alpha, and beta/gamma strains and it consistent with NGS results. Testing of clinical samples revealed that VOC emerged in Denver, CO in March 2021. Future work to discriminate beta, gamma, and emerging VOC is ongoing. In summary, VOCFast is an extraction-free RT-PCR assay for nasal swab and saliva specimens that can identify VOC with a turnaround time suitable for clinical testing. Disclosures Brian L. Harry, MD PhD, Summit Biolabs Inc. (Grant/Research Support, Shareholder) Mara Couto-Rodriguez, MS, Biotia (Employee) Dorottya Nagy-Szakal, MD PhD, Biotia Inc (Employee, Shareholder) Niamh B. O’Hara, PhD, Biotia (Board Member, Employee, Shareholder) Shi-Long Lu, MD PhD, Summit Biolabs Inc. (Grant/Research Support, Shareholder)
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Saunders, S. M., M. E. Jenkin, R. G. Derwent, and M. J. Pilling. "Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): tropospheric degradation of non-aromatic volatile organic compounds." Atmospheric Chemistry and Physics Discussions 2, no. 6 (November 7, 2002): 1847–903. http://dx.doi.org/10.5194/acpd-2-1847-2002.
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Abstract. Kinetic and mechanistic data relevant to the tropospheric degradation of volatile organic compounds (VOC), and the production of secondary pollutants, have previously been used to define a protocol which underpinned the construction of a near-explicit Master Chemical Mechanism. In this paper, an update to the previous protocol is presented, which has been used to define degradation schemes for 107 non-aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3). The treatment of 18 aromatic VOC is described in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the reactions of the radical intermediates and the further degradation of first and subsequent generation products. Emphasis is placed on updating the previous information, and outlining the methodology which is specifically applicable to VOC not considered previously (e.g. a- and b-pinene). The present protocol aims to take into consideration work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Application of MCM v3 in appropriate box models indicates that the representation of isoprene degradation provides a good description of the speciated distribution of oxygenated organic products observed in reported field studies where isoprene was the dominant emitted hydrocarbon, and that the a-pinene degradation chemistry provides a good description of the time dependence of key gas phase species in a-pinene/NOX photo-oxidation experiments carried out in the European Photoreactor (EUPHORE). Photochemical Ozone Creation Potentials (POCP) have been calculated for the 106 non-aromatic non-methane VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. Where applicable, the values are compared with those calculated with previous versions of the MCM.
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Saunders, S. M., M. E. Jenkin, R. G. Derwent, and M. J. Pilling. "Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): tropospheric degradation of non-aromatic volatile organic compounds." Atmospheric Chemistry and Physics 3, no. 1 (February 12, 2003): 161–80. http://dx.doi.org/10.5194/acp-3-161-2003.
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Abstract. Kinetic and mechanistic data relevant to the tropospheric degradation of volatile organic compounds (VOC), and the production of secondary pollutants, have previously been used to define a protocol which underpinned the construction of a near-explicit Master Chemical Mechanism. In this paper, an update to the previous protocol is presented, which has been used to define degradation schemes for 107 non-aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3). The treatment of 18 aromatic VOC is described in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the reactions of the radical intermediates and the further degradation of first and subsequent generation products. Emphasis is placed on updating the previous information, and outlining the methodology which is specifically applicable to VOC not considered previously (e.g. a- and b-pinene). The present protocol aims to take into consideration work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Application of MCM v3 in appropriate box models indicates that the representation of isoprene degradation provides a good description of the speciated distribution of oxygenated organic products observed in reported field studies where isoprene was the dominant emitted hydrocarbon, and that the a-pinene degradation chemistry provides a good description of the time dependence of key gas phase species in a-pinene/NOX photo-oxidation experiments carried out in the European Photoreactor (EUPHORE). Photochemical Ozone Creation Potentials (POCP) have been calculated for the 106 non-aromatic non-methane VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. Where applicable, the values are compared with those calculated with previous versions of the MCM.
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Carignan, Marie-Pierre, and Craig B. Lake. "Sorption and diffusion of volatile organic compounds through two thermally treated drill mud wastes." Canadian Geotechnical Journal 44, no. 5 (May 1, 2007): 592–602. http://dx.doi.org/10.1139/t07-009.
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Onshore thermal treatment of offshore drilling mud waste generates a mineral by-product, referred to in this paper as thermally treated drill mud waste (TTDMW). Environmental regulations can result in the generation of significant quantities of this material, and hence it would be beneficial from a sustainability perspective to identify a value-added recycling use for this material. Recycling TTDMW into a primary compacted soil barrier system for municipal solid waste landfills represents one such possible reuse. It is hypothesized that residual amounts of organoclays and organic carbon in the TTDMWs will act as a beneficial sorbent to low levels of volatile organic compounds (VOCs) often found in municipal solid waste leachate. To assess this hypothesis, two different TTDMW materials (from Nova Scotia and the United Kingdom) were subjected to batch and diffusion testing to assess VOC sorption. It is shown that partitioning coefficient (Kd) values obtained from diffusion testing were generally lower than those obtained from batch testing. Contaminant migration modelling of a hypothetical TTDMW barrier system using measured VOC sorption levels is presented in the paper to provide some relevance to the results obtained.Key words: drill mud waste, sorption, VOC, diffusion, landfill liner.
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Rai, Shesh N., Samarendra Das, Jianmin Pan, Dwijesh C. Mishra, and Xiao-An Fu. "Multigroup prediction in lung cancer patients and comparative controls using signature of volatile organic compounds in breath samples." PLOS ONE 17, no. 11 (November 30, 2022): e0277431. http://dx.doi.org/10.1371/journal.pone.0277431.
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Early detection of lung cancer is a crucial factor for increasing its survival rates among the detected patients. The presence of carbonyl volatile organic compounds (VOCs) in exhaled breath can play a vital role in early detection of lung cancer. Identifying these VOC markers in breath samples through innovative statistical and machine learning techniques is an important task in lung cancer research. Therefore, we proposed an experimental approach for generation of VOC molecular concentration data using unique silicon microreactor technology and further identification and characterization of key relevant VOCs important for lung cancer detection through statistical and machine learning algorithms. We reported several informative VOCs and tested their effectiveness in multi-group classification of patients. Our analytical results indicated that seven key VOCs, including C4H8O2, C13H22O, C11H22O, C2H4O2, C7H14O, C6H12O, and C5H8O, are sufficient to detect the lung cancer patients with higher mean classification accuracy (92%) and lower standard error (0.03) compared to other combinations. In other words, the molecular concentrations of these VOCs in exhaled breath samples were able to discriminate the patients with lung cancer (n = 156) from the healthy smoker and nonsmoker controls (n = 193) and patients with benign pulmonary nodules (n = 65). The quantification of carbonyl VOC profiles from breath samples and identification of crucial VOCs through our experimental approach paves the way forward for non-invasive lung cancer detection. Further, our experimental and analytical approach of VOC quantitative analysis in breath samples may be extended to other diseases, including COVID-19 detection.
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Yamamuro, Hiroki, and Masayuki Takashiri. "Power Generation in Slope-Type Thin-Film Thermoelectric Generators by the Simple Contact of a Heat Source." Coatings 9, no. 2 (January 22, 2019): 63. http://dx.doi.org/10.3390/coatings9020063.
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To conveniently generate electric energy for next-generation smart network monitoring systems, we propose the design and fabrication of slope-type thin-film thermoelectric generators by the simple contact of a heat source. N-type Bi2Te3 films and p-type Sb2Te3 films were formed on a stainless-steel substrate employing potentiostatic electrodeposition using a nitric acid-based bath, followed by a transfer process. In order to naturally induce a temperature difference (ΔT) between the ends of the generator, slope blocks made by polydimethylsiloxane (PDMS) were prepared and then inserted between the generators and heat sources. The performance of the generators, the open circuit voltage (Voc), and the maximum output power (Pmax), were measured using PDMS slope angles as the temperature of the heat source was increased. The ΔT of the generators increased as the slope angle was increased. The generator with the highest slope angle (28°) exhibited a Voc of 7.2 mV and Pmax of 18.3 μW at ΔT of 15 K for a heat source temperature of 42 °C. Our results demonstrate the feasibility of slope-type thin-film thermoelectric generators, which can be fabricated with a low manufacturing cost.
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Giglia, Graziella, Marcello Pucci, Calogero Serporta, and Gianpaolo Vitale. "Comparison of control techniques for three-phase distributed generation based on VOC and DPC." Renewable Energy and Power Quality Journal 1, no. 06 (March 2008): 659–66. http://dx.doi.org/10.24084/repqj06.401.
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Yang, Yong, Chun Qing Qi, Ji Suo, and Feng Wen Cao. "Singe-Phase Grid-Connected Inverter Based on Voltage-Oriented Control in Photovoltaic Generation Systems." Advanced Materials Research 765-767 (September 2013): 2498–502. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.2498.
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The paper proposes a new control of a transformerless singe-stage single-phase grid-connected inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with help of second order Generalized Integrator (SOGI). A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous dq reference frame using a decoupled feedback control. The simulated results have proven an excellent performance and verified the validity of proposed system.
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Young, C. J., R. A. Washenfelder, P. M. Edwards, D. D. Parrish, J. B. Gilman, W. C. Kuster, L. H. Mielke, et al. "Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles." Atmospheric Chemistry and Physics 14, no. 7 (April 7, 2014): 3427–40. http://dx.doi.org/10.5194/acp-14-3427-2014.
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Abstract. The role of chlorine atoms (Cl) in atmospheric oxidation has been traditionally thought to be limited to the marine boundary layer, where they are produced through heterogeneous reactions involving sea salt. However, recent observation of photolytic Cl precursors (ClNO2 and Cl2) formed from anthropogenic pollution has expanded the potential importance of Cl to include coastal and continental urban areas. Measurements of ClNO2 in Los Angeles during CalNex (California Nexus – Research at the Nexus of Air Quality and Climate Change) showed it to be an important primary (first generation) radical source. Evolution of ratios of volatile organic compounds (VOCs) has been proposed as a method to quantify Cl oxidation, but we find no evidence from this approach for a significant role of Cl oxidation in Los Angeles. We use a box model with the Master Chemical Mechanism (MCM v3.2) chemistry scheme, constrained by observations in Los Angeles, to examine the Cl sensitivity of commonly used VOC ratios as a function of NOx and secondary radical production. Model results indicate VOC tracer ratios could not detect the influence of Cl unless the ratio of [OH] to [Cl] was less than 200 for at least a day. However, the model results also show that secondary (second generation) OH production resulting from Cl oxidation of VOCs is strongly influenced by NOx, and that this effect obscures the importance of Cl as a primary oxidant. Calculated concentrations of Cl showed a maximum in mid-morning due to a photolytic source from ClNO2 and loss primarily to reactions with VOCs. The [OH] to [Cl] ratio was below 200 for approximately 3 h in the morning, but Cl oxidation was not evident from the measured ratios of VOCs. Instead, model simulations show that secondary OH production causes VOC ratio evolution to follow that expected for OH oxidation, despite the significant input of primary Cl from ClNO2 photolysis in the morning. Even though OH is by far the dominant oxidant in Los Angeles, Cl atoms do play an important role in photochemistry there, constituting 9% of the primary radical source. Furthermore, Cl–VOC reactivity differs from that of OH, being more than an order of magnitude larger and dominated by VOCs, such as alkanes, that are less reactive toward OH. Primary Cl is also slightly more effective as a radical source than primary OH due to its greater propensity to initiate radical propagation chains via VOC reactions relative to chain termination via reaction with nitrogen oxides.
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Forzatti, Pio, Fabrizio Arosio, and Cinzia Cristiani. "Structured Catalysts for Environmental and Energetical Applications." Advances in Science and Technology 45 (October 2006): 2188–97. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2188.
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The paper presents an overview of the present status and the perspectives for use of structured catalysts in the power generation, transport and environmental sectors. In particular catalytic combustion of natural gas for the production of energy in gas turbines, abatement of NOx from mobile and stationary sources under lean and stoichiometric conditions, removal of VOC from industrial effluents and soot combustion in the exhaust gases of vehicles are discussed.
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Yang, Hwa-Young, Ana Chuquer, Seung-Hee Han, Gangasagar Sharma Gaudel, Xuan-Hung Pham, Hyung-Mo Kim, Won-Ju Yun, Bong-Hyun Jun, and Won-Yeop Rho. "Optimizing the Aspect Ratio of Nanopatterned Mesoporous TiO2 Thin-Film Layer to Improve Energy Conversion Efficiency of Perovskite Solar Cells." International Journal of Molecular Sciences 22, no. 22 (November 12, 2021): 12235. http://dx.doi.org/10.3390/ijms222212235.
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The energy conversion efficiency (ECE) (η), current density (Jsc), open-circuit voltage (Voc), and fill factor (ff) of perovskite solar cells were studied by using the transmittance of a nanopatterned mesoporous TiO2 (mp-TiO2) thin-film layer. To improve the ECE of perovskite solar cells, a mp-TiO2 thin-film layer was prepared to be used as an electron transport layer (ETL) via the nanoimprinting method for nanopatterning, which was controlled by the aspect ratio. The nanopatterned mp-TiO2 thin-film layer had a uniform and well-designed structure, and the diameter of nanopatterning was 280 nm. The aspect ratio was controlled at the depths of 75, 97, 127, and 167 nm, and the perovskite solar cell was fabricated with different depths. The ECE of the perovskite solar cells with the nanopatterned mp-TiO2 thin-film layer was 14.50%, 15.30%, 15.83%, or 14.24%, which is higher than that of a non-nanopatterned mp-TiO2 thin-film layer (14.07%). The enhancement of ECE was attributed to the transmittance of the nanopatterned mp-TiO2 thin-film layer that is due to the improvement of the electron generation. As a result, better electron generation affected the electron density, and Jsc increased the Voc, and ff of perovskite solar cells.
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Reincke, S. Momsen, Meng Yuan, Hans-Christian Kornau, Victor M. Corman, Scott van Hoof, Elisa Sánchez-Sendin, Melanie Ramberger, et al. "SARS-CoV-2 Beta variant infection elicits potent lineage-specific and cross-reactive antibodies." Science 375, no. 6582 (February 18, 2022): 782–87. http://dx.doi.org/10.1126/science.abm5835.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Beta variant of concern (VOC) resists neutralization by major classes of antibodies from COVID-19 patients and vaccinated individuals. In this study, serum of Beta-infected patients revealed reduced cross-neutralization of wild-type virus. From these patients, we isolated Beta-specific and cross-reactive receptor-binding domain (RBD) antibodies. The Beta-specificity results from recruitment of VOC-specific clonotypes and accommodation of mutations present in Beta and Omicron into a major antibody class that is normally sensitive to these mutations. The Beta-elicited cross-reactive antibodies share genetic and structural features with wild type–elicited antibodies, including a public VH1-58 clonotype that targets the RBD ridge. These findings advance our understanding of the antibody response to SARS-CoV-2 shaped by antigenic drift, with implications for design of next-generation vaccines and therapeutics.
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Yang, Geum-Hee, Yu-Jin Jo, Hyo-Jung Lee, Chang-Keun Song, and Cheol-Hee Kim. "Numerical Sensitivity Tests of Volatile Organic Compounds Emission to PM2.5 Formation during Heat Wave Period in 2018 in Two Southeast Korean Cities." Atmosphere 11, no. 4 (March 29, 2020): 331. http://dx.doi.org/10.3390/atmos11040331.
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A record-breaking severe heat wave was recorded in southeast Korea from 11 July to 15 August 2018, and the numerical sensitivity simulations of volatile organic compound (VOC) to secondarily generated particulate matter with diameter of less than 2.5 µm (PM2.5) concentrations were studied in the Busan and Ulsan metropolitan areas in southeast Korea. A weather research and forecasting (WRF) model coupled with chemistry (WRF-Chem) was employed, and we carried out VOC emission sensitivity simulations to investigate variations in PM2.5 concentrations during the heat wave period that occurred from 11 July to 15 August 2018. In our study, when anthropogenic VOC emissions from the Comprehensive Regional Emissions Inventory for Atmospheric Transport Experiment-2015 (CREATE-2015) inventory were increased by approximately a factor of five in southeast Korea, a better agreement with observations of PM2.5 mass concentrations was simulated, implying an underestimation of anthropogenic VOC emissions over southeast Korea. The simulated secondary organic aerosol (SOA) fraction, in particular, showed greater dominance during high temperature periods such as 19–21 July, 2018, with the SOA fractions of 42.3% (in Busan) and 34.3% (in Ulsan) among a sub-total of seven inorganic and organic components. This is considerably higher than observed annual mean organic carbon (OC) fraction (28.4 ± 4%) among seven components, indicating the enhancement of secondary organic aerosols induced by photochemical reactions during the heat wave period in both metropolitan areas. The PM2.5 to PM10 ratios were 0.69 and 0.74, on average, during the study period in the two cities. These were also significantly higher than the typical range in those cities, which was 0.5–0.6 in 2018. Our simulations implied that extremely high temperatures with no precipitation are significantly important to the secondary generation of PM2.5 with higher secondary organic aerosol fraction via photochemical reactions in southeastern Korean cities. Other possible relationships between anthropogenic VOC emissions and temperature during the heat wave episode are also discussed in this study.
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Kato, Kunihiko, Fumiaki Kobayashi, Yunzi Xin, Sohei Nakagawa, Harumitsu Nishikawa, and Takashi Shirai. "HAp/TiO2 heterojunction catalyst towards low-temperature thermal oxidation of VOC." Materials Research Express 9, no. 2 (February 1, 2022): 020007. http://dx.doi.org/10.1088/2053-1591/ac5350.
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Abstract Ceramic catalyst without precious metals and rare-earth elements is a promising technology for removing volatile organic compounds (VOC) produced in the manufacturing process to feasibly solve worldwide health and environmental problems. We first investigate the influence of hydroxyapatite (HAp)/TiO2 heterojunction formation on the temperature dependence of VOC catalytic performance. The comprehensive evaluation by XRD, FT-IR, UV–vis, and in situ ESR clarifies that the anisotropic crystal distortion along the c-axis of HAp lattice is caused by hydrolysis and hetero-condensation of TiO2 precursor accompanying with the defective structure in HAp. The structural modified HAp (m-HAp) provides the notable alteration of optical bandgap with the visible-light coloration and the preferential generation of oxygen radicals. Furthermore, we propose a new model that the m-HAp/TiO2 heterojunction should be a possible main factor affecting the more than twice higher catalytic performance in thermal oxidation of ethyl acetate at a lower temperature, as typically shown in HAp-T1.
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Fisher, R. M., R. J. Barczak, J. P. Alvarez Gaitan, N. Le-Minh, and R. M. Stuetz. "Odorous volatile organic compound (VOC) emissions from ageing anaerobically stabilised biosolids." Water Science and Technology 75, no. 7 (January 20, 2017): 1617–24. http://dx.doi.org/10.2166/wst.2017.030.
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Opportunities for the beneficial re-use of biosolids are limited by nuisance odour emissions. Volatile organic compounds (VOCs) from anaerobically stabilised biosolids were measured to identify compounds that could contribute to the overall odour character of nuisance emissions. Flux hood sampling and chemical analysis were used to identify VOCs emitted from biosolids as they were stored in ambient conditions. Compounds emitted varied as the biosolid cakes were stored for a period of 50 days. VOCs detected in the biosolids are likely to occur from catchment sources as well as abiotic and biotic generation in the wastewater processing and the biosolids as they are stored. Odour activity values (OAVs) were used to compare odorants. Trimethylamine was the only VOC detected that exceeded the sulfur compounds in terms of OAVs. Other compounds such as limonene, ethyl methyl benzene and acetic acid were detected at concentrations exceeding their olfactory detection limits, however at lower OAVs than sulfur compounds.
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Tsigaridis, K., and M. Kanakidou. "Global modelling of secondary organic aerosol in the troposphere: A sensitivity analysis." Atmospheric Chemistry and Physics Discussions 3, no. 3 (June 2, 2003): 2879–929. http://dx.doi.org/10.5194/acpd-3-2879-2003.
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Abstract. A global 3-dimensional chemistry/transport model able to describe O3, NOx, Volatile Organic Compounds (VOC), sulphur and NH3 chemistry has been extended to simulate the temporal and spatial distribution of primary and secondary carbonaceous aerosols in the troposphere focusing on Secondary Organic Aerosol (SOA) formation. A number of global simulations have been performed to determine a possible range of annual global SOA production and investigate uncertainties associated with the model results. Uncertainties in the model calculations related to the enthalpy of vaporization, the solubility and the activity coefficient of the condensable species, the chemical fate of the first generation low volatility oxidation products, the ageing of particles with regard to their hydrophilic properties, the partitioning of SOA on various aerosol surfaces and the evaporation of semi-volatiles from aerosol surfaces have been evaluated. Although not all sources of uncertainties have been investigated, according to our calculations, the above factors within the experimental range of variations could result to an overall uncertainty of about a factor of 20 in the global SOA budget. The global annual SOA production from biogenic VOC might range from 2.5 to 44.5 Tg of organic matter per year, whereas that from anthropogenic VOC ranges from 0.05 to 2.62 Tg of organic matter per year. These estimates can be considered as a lower limit, since partitioning on coarse particles like nitrate, dust or sea-salt, together with the partitioning and the dissociation of the semi-volatile products in aerosol water has been neglected. The large uncertainties associated with the emissions of VOC have not been investigated in this study. Comparison of model results to observations, where available, shows a better agreement for the upper budget estimates than for the lower ones.
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Tsigaridis, K., and M. Kanakidou. "Global modelling of secondary organic aerosol in the troposphere: a sensitivity analysis." Atmospheric Chemistry and Physics 3, no. 5 (October 31, 2003): 1849–69. http://dx.doi.org/10.5194/acp-3-1849-2003.
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Abstract. A global 3-dimensional chemistry/transport model able to describe O3, NOx, Volatile Organic Compounds (VOC), sulphur and NH3 chemistry has been extended to simulate the temporal and spatial distribution of primary and secondary carbonaceous aerosols in the troposphere focusing on Secondary Organic Aerosol (SOA) formation. A number of global simulations have been performed to determine a possible range of annual global SOA production and investigate uncertainties associated with the model results. The studied uncertainties in the SOA budget have been evaluated to be in decreasing importance: the potentially irreversible sticking of the semi-volatile compounds on aerosols, the enthalpy of vaporization of these compounds, the partitioning of SOA on non-carbonaceous aerosols, the conversion of aerosols from hydrophobic to hydrophilic, the emissions of primary carbonaceous aerosols, the chemical fate of the first generation products and finally the activity coefficient of the condensable species. The large uncertainties associated with the emissions of VOC and the adopted simplification of chemistry have not been investigated in this study. Although not all sources of uncertainties have been investigated, according to our calculations, the above factors within the experimental range of variations could result to an overall uncertainty of about a factor of 20 in the global SOA budget. The global annual SOA production from biogenic VOC might range from 2.5 to 44.5 Tg of organic matter per year, whereas that from anthropogenic VOC ranges from 0.05 to 2.62 Tg of organic matter per year. These estimates can be considered as a lower limit, since partitioning on coarse particles like nitrate, dust or sea-salt, together with the partitioning and the dissociation of the semi-volatile products in aerosol water has been neglected. Comparison of model results to observations, where available, shows a better agreement for the upper budget estimates than for the lower ones.
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Bhuthukuri, Rajesh Khanna, and Poonam Upadhyay. "Comparative Analysis of Control Techniques for PWM Rectifiers in Grid Connected Distributed Generation Systems Based on VOC and DPC." International Journal of Research and Engineering 5, no. 2 (March 2018): 303–10. http://dx.doi.org/10.21276/ijre.2018.5.2.1.
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Zhao, Fang Ping, and Yong Yang. "Three-Level Grid-Connected Inverter Based on Voltage-Oriented Control in Photovoltaic Generation Systems." Advanced Materials Research 765-767 (September 2013): 2494–97. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.2494.
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The paper propose a new control of a three-phase three-level neutral-point-clamped (NPC) pulse width modulated (PWM) inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with an improved maximum power point (MPP) tracking (MPPT). A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous dq reference frame using a decoupled feedback control. Furthermore, in order to achieve a unity power factor, the q-axis current reference is set to zero. The experimental results have proven an excellent performance and verified the validity of proposed system.
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Karthika, J. "DSP Based Maximum Power Point Tracking (MPPT) for Improving the Performance of DFIG." Applied Mechanics and Materials 550 (May 2014): 157–65. http://dx.doi.org/10.4028/www.scientific.net/amm.550.157.
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In the recent years, wind power has been developed rapidly. So most of the research work focus towards the variable speed power generation rather than fixed speed power generation in wind energy conversion system. This paper presents a maximum power point tracking (MPPT) technique for an improved power quality, high energy efficiency and controllability. For the experimental application a Back – to - Back configuration with two voltage source converters has been considered one on the machine side and another on the grid side. Each converter has been controlled with a high performance vector control technique ie FOC & VOC respectively. Two DSPs have been used to control both the inverters. Simulation result shows that the Digital Signal Processor provides effectiveness in controlling under different operating conditions.
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Jiang, Yanting, Jia Yan, Ci’en Fan, Wenxuan Shi, and Dexiang Deng. "An improved real-time object proposals generation method based on local binary pattern." International Journal of Advanced Robotic Systems 14, no. 4 (July 1, 2017): 172988141772467. http://dx.doi.org/10.1177/1729881417724679.
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Generating a group of category-independent proposals of objects in an image within a very short time is an effective approach to accelerate traditional sliding window search, which has been widely used in preprocessing step of object recognition. In this article, we propose a novel object proposals generation method to produce an order set of candidate windows covering most of object instances. With combination of gradient and local binary pattern, our approach achieves better performance than BING in finding occluded objects and objects in dim lighting conditions. In experiments on the challenging PASCAL VOC 2007 data set, we show that our approach is significantly more accurate than BING. In particular, using 2000 proposals, we achieve 97.6% object detection rate and 69.3% mean average best overlap. Moreover, our proposed method is very efficient and takes only about 0.006 s per image on a laptop central processing unit. The detection speed and high accuracy of proposed method mean that it can be applied to recognizing specific objects in robot visions.
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Warden, Andrew C., Stephen C. Trowell, and Murat Gel. "A Miniature Gas Sampling Interface with Open Microfluidic Channels: Characterization of Gas-to-Liquid Extraction Efficiency of Volatile Organic Compounds." Micromachines 10, no. 7 (July 19, 2019): 486. http://dx.doi.org/10.3390/mi10070486.
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Chemosensory protein based olfactory biosensors are expected to play a significant role in next-generation volatile organic compound (VOC) detection systems due to their ultra-high sensitivity and selectivity. As these biosensors can perform most efficiently in aqueous environments, the detection systems need to incorporate a gas sampling interface for gas-to-liquid extraction. This interface should extract the VOCs from the gas phase with high efficiency and transfer them into the liquid containing biosensors to enable subsequent detection. To design such a transfer interface, an understanding of the key parameters influencing the gas-to-liquid extraction efficiency of target VOCs is crucial. This paper reports a gas sampling interface system based on a microfluidic open-channel device for gas-to-liquid extraction. By using this device as a model platform, the key parameters dictating the VOC extraction efficiency were identified. When loaded with 30 μL of capture liquid, the microfluidic device generates a gas-liquid interface area of 3 cm2 without using an interfacial membrane. The pumpless operation based on capillary flow was demonstrated for capture liquid loading and collection. Gas samples spiked with lipophilic model volatiles (hexanal and allyl methyl sulfide) were used for characterization of the VOC extraction efficiency. Decreasing the sampling temperature to 15 °C had a significant impact on increasing capture efficiency, while variation in the gas sampling flow rate had no significant impact in the range between 40–120 mL min−1. This study found more than a 10-fold increase in capture efficiency by chemical modification of the capture liquid with alpha-cyclodextrin. The highest capture efficiency of 30% was demonstrated with gas samples spiked with hexanal to a concentration of 16 ppm (molar proportion). The approach in this study should be useful for further optimisation of miniaturised gas-to-liquid extraction systems and contribute to the design of chemosensory protein-based VOC detection systems.
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Htut, Han Min, and Wijarn Wangdee. "Virtual Oscillator Control of Multiple Solar PV Inverters for Microgrid Applications." Engineering Journal 24, no. 5 (September 30, 2020): 173–83. http://dx.doi.org/10.4186/ej.2020.24.5.173.
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This paper proposes the inverter control strategy for multiple solar PV generation sources based on the two-stage converters with a combination of the modified virtual oscillator control (VOC) and the cascaded sliding mode control (SMC). With this proposed control strategy, the load power-sharing in proportion to the inverter rating is guaranteed when the solar PV output satisfies the power-sharing requirement. On the other hand, the control algorithm autonomously forces the solar PV to operate at the maximum power point if the solar PV output is lower than the power-sharing requirement. Various operating scenarios have been simulated to appreciate the effectiveness of the proposed control scheme for ensuring the load-power sharing and maintaining the voltage and frequency stability of the islanded microgrid containing a 100% solar PV generation.
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Seco, R., J. Peñuelas, I. Filella, J. Llusià, R. Molowny-Horas, S. Schallhart, A. Metzger, M. Müller, and A. Hansel. "Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions." Atmospheric Chemistry and Physics Discussions 11, no. 7 (July 19, 2011): 20389–431. http://dx.doi.org/10.5194/acpd-11-20389-2011.
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Abstract. Atmospheric volatile organic compounds (VOCs) are involved in ozone and aerosol generation, thus having implications for air quality and climate. VOCs and their emissions by vegetation also have important ecological roles as they can protect plants from stresses and act as communication cues between plants and between plants and animals. In spite of these key environmental and biological roles, the reports on seasonal and daily VOC mixing ratios in the literature for Mediterranean natural environments are scarce. We conducted seasonal (winter and summer) measurements of VOC mixing ratios in an elevated (720 m a.s.l.) holm oak Mediterranean forest site near the metropolitan area of Barcelona (NE Iberian peninsula). Methanol was the most abundant compound among all the VOCs measured in both seasons. While aromatic VOCs showed almost no seasonal variability, short-chain oxygenated VOCs presented higher mixing ratios in summer, presumably due to greater emission by vegetation and increased photochemistry, both enhanced by the high temperatures and solar radiation in summer. Isoprenoid VOCs showed the biggest seasonal change in mixing ratios: they increased by one order of magnitude in summer, as a result of the vegetation's greater physiological activity and emission rates. The maximum diurnal concentrations of ozone increased in summer too, most likely due to more intense photochemical activity and the higher levels of VOCs in the air. The daily variation of VOC mixing ratios was mainly governed by the wind regime of the mountain, as the majority of the VOC species analyzed followed a very similar diel cycle. Mountain and sea breezes that develop after sunrise advect polluted air masses to the mountain. These polluted air masses had previously passed over the urban and industrial areas surrounding the Barcelona metropolitan area, where they were enriched in NOx and in VOCs of biotic and abiotic origin. Moreover, these polluted air masses receive additional biogenic VOCs emitted in the local valley by the vegetation, thus enhancing O3 formation in this forested site. The only VOC species that showed a somewhat different daily pattern were monoterpenes because of their local biogenic emission. Isoprene also followed in part the daily pattern of monoterpenes, but only in summer when its biotic sources were stronger. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources.