Activation Time
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Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6116
Yixin Zhang ◽  
Rumeng Wang ◽  
Guofeng Qiu ◽  
Wenke Jia ◽  
Yang Guo ◽  

A large amount of coal gasification slag is produced every year in China. However, most of the current disposal is into landfills, which causes serious harm to the environment. In this research, coal gasification fine slag residual carbon porous material (GFSA) was prepared using gasification fine slag foam flotation obtained carbon residue (GFSF) as raw material and an adsorbent to carry out an adsorption test on waste liquid containing methylene blue (MB). The effects of activation parameters (GFSF/KOH ratio mass ratio, activation temperature, and activation time) on the cation exchange capacity (CEC) of GFSA were investigated. The total specific surface area and pore volume of GSFA with the highest CEC were 574.02 m2/g and 0.467 cm3/g, respectively. The degree of pore formation had an important effect on CEC. The maximum adsorption capacity of GFSA on MB was 19.18 mg/g in the MB adsorption test. The effects of pH, adsorption time, amount of adsorbent, and initial MB concentration on adsorption efficiency were studied. Langmuir isotherm and quasi second-order kinetic model have a good fitting effect on the adsorption isotherm and kinetic model of MB.

2021 ◽  
Vol 45 (1) ◽  
Enebi Estella Jasper ◽  
Jude Chinedu Onwuka ◽  
Yakubu Manasseh Bidam

Abstract Background The use of active carbons derived from waste biomass as adsorbents in the remediation of wastewater remains a valuable and cost-effective technology when compared to the use of commercial active carbon for the same purpose. This research aims at using a 2-level full factorial design (FFD) to efficiently evaluate factors that influence the preparation of active carbon from the waste pods of the Dialium guineense seeds. The influence of three preparation factors (concentration of the activating agent, activation time, and type of activating agent) on the active carbon yield and its adsorption capacity for methylene blue were investigated. Based on the full factorial design, two regression models were developed to correlate the factors to the two responses. From an analysis of variance (ANOVA), the most significant factors influencing each response were identified. The active carbon preparation conditions were then optimized by maximizing both the active carbon yield and its adsorption capacity for Methylene Blue. The functional group and surface morphology of the active carbon prepared under the predicted optimum conditions was analyzed via Fourier Transform Infra-Red (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) respectively. Results The results of this study revealed that the concentration of the activating agent had the most significant effect on the yield of the active carbon produced as well as on its adsorption capacity for methylene blue. The optimum preparation process conditions were found to be: concentration of activating agent 5M, activation time 30 min and activating agent, NaOH which resulted in an active carbon yield of 21.25%, and an adsorption capacity of 9.33509 mg MB per gram of active carbon. SEM and FTIR showed evidence of successful activation. Conclusion The preparation of Dialium guineense seed pods' active carbon is strongly influenced by concentration and type of activating agent used. Reliable statistical models based on the FFD proved to be useful in identifying factors that significantly influence the preparation of Dialium guineense seed pods' active carbon. The active carbon holds great potential for application in the elimination of hazardous synthetic dyes from wastewater and should be explored further.

2021 ◽  
Jose-María Navalpotro-Pascual ◽  
Diana Monge-Martín ◽  
Manuel-José González-León ◽  
Fernando Neria ◽  
Francisco Peinado-Vallejo ◽  

Abstract Background: COVID-19 has led to decreased survival of out-of-hospital cardiorespiratory arrest (OHCA). We analysed the impact of the first COVID-19 pandemic year on emergency medical services and OHCA care compared with the previous year.Methods: Data for this observational study were collected for OHCAs attended by the SUMMA 112 emergency service during March 2019 to March 2021. We compared data covering 15 March 2020–14 March 2021 (pandemic year) to retrospective data covering 15 March 2019–14 March 2020 (non-pandemic year). Results: During the pandemic period, 1743 OHCA patients were attended, compared to 1781 during the non-pandemic year. Median patient age during the pandemic period was lower than in the non-pandemic period (71 vs 72, p=0·037). Emergency services response activation time increased during the pandemic year, to 3 minutes, 16 seconds from 2 minutes, 48 seconds in the non-pandemic period (p=0·001). Time to arrival at the scene also increased during the pandemic (12 minutes vs 11 minutes, 25 seconds before the pandemic; p=0·001). The percentage of OHCAs in which resuscitation was attempted was lower during the pandemic (59·4% vs 62·9%, p=0·034), as were survival on hospital arrival (30·3% vs 34·6%, p=0·04). Differences in response activation time (p=0·003) and scene arrival times (p=0·003) were greater during the first pandemic wave compared with the later phases. Conclusions: The different phases of the pandemic variably affected OHCA care. The first wave led to longer resource activation, increased home events and scene arrival times, as well as lower patient survival.

2021 ◽  
Vol 50 (9) ◽  
pp. 671-678 ◽  
Zhenghong Liu ◽  
Mian Jie Lim ◽  
Pin Pin Pek ◽  
Aaron Sung Lung Wong ◽  
Kenneth Boon Kiat Tan ◽  

ABSTRACT Introduction: Early reperfusion of ST-segment elevation myocardial infarction (STEMI) results in better outcomes. Interventions that have resulted in shorter door-to-balloon (DTB) time include prehospital cardiovascular laboratory activation and prehospital electrocardiogram (ECG) transmission, which are only available for patients who arrive via emergency ambulances. We assessed the impact of mode of transport on DTB time in a single tertiary institution and evaluated the factors that affected various components of DTB time. Methods: We conducted a retrospective cohort study using registry data of patients diagnosed with STEMI in the emergency department (ED) who underwent primary percutaneous coronary intervention. We compared patients who arrived by emergency ambulances with those who came via their own transport. The primary study end point was DTB, defined as the earliest time a patient arrived in the ED to balloon inflation. As deidentified data was used, ethics review was waived. Results: A total of 321 patients were included for analysis after excluding 7 with missing data. The mean age was 61.4±11.4 years old with 49 (15.3%) females. Ninety-nine (30.8%) patients arrived by emergency ambulance. The median DTB time was shorter for patients arriving by ambulance versus own transport (52min, interquartile range [IQR] 45–61 vs 67min, IQR 59–74; P<0.001), with shorter door-to-ECG and door-to-activation time. Conclusion: Arrival via emergency ambulance was associated with a decreased DTB for STEMI patients compared to arriving via own transport. There is a need for public education to increase the usage of emergency ambulances for suspected heart attacks to improve outcomes. Keywords: Cardiovascular lab activation, door-to-balloon time, emergency ambulance, primary PCI, STEMI

2021 ◽  
Mirsaeid Hosseini shirvani

Abstract Directional sensor networks are ad hoc networks which are utilized in different applications to monitor and coverage all of the specific targets in the observing fields permanently. These kinds of networks include several configurable directional sensors in which they can be adjusted in one the possible directions along with one of its adjustable ranges. Although the energy harvesting methodology is being applied for these battery-hungry applications, the battery management and network lifetime maximization is still a challenge. This paper formulates the expansion of directional sensor network lifespan to a discrete optimization problem. Several proposals were presented in literature to solve the stated problem, but majority of them are threatened to get stuck in local optimum and led low efficiency. To solve this combinatorial problem, an advanced discrete cuckoo search algorithm is designed and is called several times until the remaining battery associated to alive sensors do not let observe all targets. In each time, algorithm returns an efficient cover along with its activation time. A cover is a sub set of available sensors capable of monitoring all targets in the observing field. In the determined activation time, the sensors in the cover are scheduled in wakeup mode whereas others are set in sleep mode to save energy. Designing miscellaneous discrete walking around procedures makes to reach a good balance between exploration and exploitation in search space. The proposed algorithm has been tested in different scenarios to be evaluated. The simulation results in variety circumstances proves the superiority of the proposed algorithm is about 19.33%, 14.83%, 13.50%, and 5.33% in term of average lifespan improvement against H-MNLAR, ACOSC, GA, and HDPSO algorithms respectively.

2021 ◽  
Vol 8 ◽  
Zhao Wang ◽  
Haojie Zhu ◽  
Xiaofei Li ◽  
Yan Yao ◽  
Zhimin Liu ◽  

Background: Left bundle branch area pacing (LBBAP) is a novel physiological pacing approach.Objective: To assess learning curve for LBBAP and compare the procedure and fluoroscopy time between LBBAP and right ventricular pacing (RVP).Methods: Consecutive bradycardia patients who underwent LBBAP or RVP were prospectively recruited from June 2018 to June 2020. The procedure and fluoroscopy time for ventricular lead placement, pacing parameters, and periprocedural complications were recorded. Restricted cubic splines were used to fit learning curves for LBBAP.Results: Left bundle branch area pacing was successful in 376 of 406 (92.6%) patients while 313 patients received RVP. Learning curve for LBBAP illustrated initial (1–50 cases), improved (51–150 cases), and stable stages (151–406 cases) with gradually increased success rates (88.0 vs. 90.0 vs. 94.5%, P = 0.106), steeply decreased median procedure (26.5 vs. 14.0 vs. 9.0min, P &lt; 0.001) and fluoroscopy time (16.0 vs. 6.0 vs. 4.0min, P &lt; 0.001), and shortened stimulus to left ventricular activation time (Sti-LVAT; 78.7 vs. 78.1 vs. 71.2 ms, P &lt; 0.001). LBBAP at the stable stage showed longer but close median procedure (9.0 vs. 6.9min, P &lt; 0.001) and fluoroscopy time (4.0 vs. 2.8min, P &lt; 0.001) compared with RVP.Conclusion: The procedure and fluoroscopy time of LBBAP could be reduced significantly with increasing procedure volume and close to that of RVP for an experienced operator.

2021 ◽  
Vol 12 ◽  
Louise Arno ◽  
Jan Quan ◽  
Nhan T. Nguyen ◽  
Maarten Vanmarcke ◽  
Elena G. Tolkacheva ◽  

During cardiac arrhythmias, dynamical patterns of electrical activation form and evolve, which are of interest to understand and cure heart rhythm disorders. The analysis of these patterns is commonly performed by calculating the local activation phase and searching for phase singularities (PSs), i.e., points around which all phases are present. Here we propose an alternative framework, which focuses on phase defect lines (PDLs) and surfaces (PDSs) as more general mechanisms, which include PSs as a specific case. The proposed framework enables two conceptual unifications: between the local activation time and phase description, and between conduction block lines and the central regions of linear-core rotors. A simple PDL detection method is proposed and applied to data from simulations and optical mapping experiments. Our analysis of ventricular tachycardia in rabbit hearts (n = 6) shows that nearly all detected PSs were found on PDLs, but the PDLs had a significantly longer lifespan than the detected PSs. Since the proposed framework revisits basic building blocks of cardiac activation patterns, it can become a useful tool for further theory development and experimental analysis.

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5641
Krittamet Phothong ◽  
Chaiyot Tangsathitkulchai ◽  
Panuwat Lawtae

Pore development and the formation of oxygen functional groups were studied for activated carbon prepared from bamboo (Bambusa bambos) using a two-step activation with CO2, as functions of carbonization temperature and activation conditions (time and temperature). Results show that activated carbon produced from bamboo contains mostly micropores in the pore size range of 0.65 to 1.4 nm. All porous properties of activated carbons increased with the increase in the activation temperature over the range from 850 to 950 °C, but decreased in the temperature range of 950 to 1000 °C, due principally to the merging of neighboring pores. The increase in the activation time also increased the porous properties linearly from 60 to 90 min, which then dropped from 90 to 120 min. It was found that the carbonization temperature played an important role in determining the number and distribution of active sites for CO2 gasification during the activation process. Empirical equations were proposed to conveniently predict all important porous properties of the prepared activated carbons in terms of carbonization temperature and activation conditions. Oxygen functional groups formed during the carbonization and activation steps of activated carbon synthesis and their contents were dependent on the preparation conditions employed. Using Boehm’s titration technique, only phenolic and carboxylic groups were detected for the acid functional groups in both the chars and activated carbons in varying amounts. Empirical correlations were also developed to estimate the total contents of the acid and basic groups in activated carbons in terms of the carbonization temperature, activation time and temperature.

Marek Jastrzębski ◽  
Paweł Moskal ◽  
Piotr Kukla ◽  
Agnieszka Bednarek ◽  
Grzegorz Kiełbasa ◽  

2021 ◽  
Iman Salimi Nezhad ◽  
Mohammad Golzar ◽  
Amirhossein Behravesh ◽  
Shahabaddin Zare

Abstract 4D printing of shape shifting structures, aka “hinges”, has raised a new standard in many fields. By using these hinges in certain parts of a 3D printed structures, a pre designed complex 3D shape with potential multifunctional application can be achieved from flat structure. This paper proposes a comprehensive semi-empirical model to predict the final shape shifting behavior and magnitude of the hinges printed by FDM process. First, all FDM main parameters are selected and reduced by design of experiment to printing speed, lamina thickness, nozzle temperature as well as printing pattern. In order to develop the model, a time-dependent constitutive model with these four process parameters were extracted for strain of an SMP homogeneous single layer structure using a fractional Zener model accompanied with Multiple Linear Regression (MLR) technique. Thereafter, the mathematical relations for shape shifting behavior of bilayer 4D printed structures were developed for beam bending and twisting by modifying Timoshenko’s constitutive equations. A comprehensive shape-shifting model was established including 3D printing parameters, angles, thickness ratios, activation time and temperature which was compared to the experimental data and results predicted both shape shifting behavior and magnitude of the hinges with good agreement. In addition, a novel flowchart was suggested to design and achieve the desired shape shifting behaviors. The proposed model and flowchart are novel tools to design 4D structures through desired shape-shifting of the hinges.

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