Activation Parameters Research Articles

Relationship of Self-Reported Physical Activity with Cognition in Middle- Aged Adults.

The increasing prevalence of age-related cognitive decline highlights the importance of physical activity for cognitive health. Regular exercise has been associated with improved mental health and reduced risk of cognitive decline. This study investigated the connection between self-reported physical activity and cognitive function in middle-aged adults. This cross-sectional study included 56 Indian adults aged 30-55, selected based on a health screening questionnaire. Participants reported their physical activity using the International Physical Activity Questionnaire-Short Form (IPAQ-SF), which categorized them into low, moderate, and high activity levels. Cognitive functions, including visual memory, executive function, and attention, were assessed using the Cambridge Neuropsychological Automated Testing Battery (CANTAB). Results were statistically analyzed for relationships between cognitive domains and physical activity parameters using Pearson's correlation and linear regression analysis. The study showed a significant positive correlation of attention with moderate and vigorous physical activity, while sedentary behavior negatively impacted attention. Linear regression showed that attention is affected by moderate-intensity activity whereas executive function and visual memory are affected by age. This study supports the view that moderate and vigorous intensity activities may positively affect attention in middle-aged adults highlighting the benefits of physical activity.

Field theory of active chiral hard disks: a first-principles approach to steric interactions

A first-principles approach for active chiral hard disks is presented, that explicitly accounts for steric interactions on the two-body level. We derive an effective one-body equation for the joint probability distribution of positions and angles of the particles. By projecting onto the angular modes, we write a hierarchy for the lowest hydrodynamic modes, i.e. particle density, polarisation, and nematic tensor. Introducing dimensionless variables in the equations, we highlight the assumptions, which—though inherent—are often included implicit in typical closure schemes of the hierarchy. By considering different regimes of the Péclet number, the well-known models in active matter can be obtained through our consideration. Explicitly, we derive an effective diffusive description and by going to higher orders in the closure scheme, we show that this first-principles approach results in the recently introduced Active Model B +, a natural extension of the Model B for active processes. Remarkably, here we find that chirality can change the sign of the phenomenological activity parameters.

The association between parameters of physical activity and olfactory function-the importance of frequency and moderate intensity.

Overall physical activity (PA) has been linked to decreased olfactory dysfunction and could improve olfactory function. Additionally, decreased olfactory function can contribute to reduced overall PA levels, given its association with neurodegenerative disorders. This study aims to examine the relationship between specific PA parameters (duration, frequency, intensity) and olfactory function in adults. A total of 3,527 participants from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 underwent assessments for weekly PA duration, frequency, and intensity, alongside a smell test (including odors such as chocolate, strawberry, grape, onion, smoke, natural gas, leather, and soap). Correlation analyses and binary logistic regressions using SPSS were used to evaluate associations. The total smell score exhibited small yet significant positive correlations with the duration, frequency, and volume of moderate PA (correlation coefficients ranging between 0.05 and 0.08; all p ≤ 0.05) and frequency of vigorous PA (correlation coefficient of 0.05; p < 0.05). For moderate PA, the duration, frequency, and volume were significantly and positively associated with the ability to correctly detect the smell of grapes while the frequency was significantly and positively associated with the ability to identify smoke and leather odors (odds ratios ranging from 1.01 to 1.07; p < 0.05). For vigorous PA, the frequency of PA was positively associated with the detection of grape smell (odds ratio of 1.05; p < 0.05). Some parameters of an active lifestyle are associated with improved odds of accurately identifying odors by up to 7.4%. Moderate PA duration, frequency, and volume were linked to better olfactory scores, while high-intensity PA had limited associations.

Evaluation of the RAID Score in Assessing Rheumatoid Arthritis Activity in Teleconsultation.

To evaluate the relevance of the RAID score as a disease activity marker of rheumatoid arthritis (RA) in a teleconsultation setting. Prospective observational 24-months duration single-center study, involving RA patients who underwent teleconsultations. The RAID score was sent to all patients via email, and completed the day before the scheduled session. The RAID questionnaire was also completed just prior the next scheduled face-to-face consultation. The same physician performed teleconsultation / in-person consultations and was unaware of the RAID results. We included 70 patients (mean age: 50±14 years, mean disease duration: 10±9 years). The RAID score correlated with the following items: patient global assessment (r=0.55, p<0.001), patient-reported swollen joint count (r=0.50, p<0.001) and DAS28-CRP calculated with patient self-reported tender/swollen joints (r=0.74, p<0.001). The RAID score completed during the next face-to-face consultation for 45 patients also correlated with the DAS28-CRP performed by the clinician (r=0.65, p<0.001). A RAID score >2 was associated with the best combination of sensitivity (94%) and specificity (43%) for the indication of rapid in-person consultation because of insufficiently controlled disease activity, with an AUC of 0.74. All 23 patients with RAID<2 had no intercurrent flares, overall PGA was 1.6±1.4/10, DAS28-CRP 1.5±0.2 and CRP 1.8±1.4 mg/L. our findings reinforce RAID score as a valuable tool in teleconsultation, exhibiting a good correlation with disease activity parameters. Using a RAID score threshold of 2 during teleconsultations could distinguish patients with good disease control and those with the potential need for in person visit.

Design and Implementation of Water PH Level and Turbidity Monitoring System

Abstract: Building collapses have become a distressing and recurring issue in Nigeria, necessitating urgent action to mitigate their occurrence. This paper introduces an innovative approach to address this challenge by developing an Automated Structural Health Monitoring System (ASHMS) utilizing a mobile app. Focusing on major cities like Lagos and Abuja, the proposed system employs strategically placed sensors to gather data from various structural elements of buildings. The collected information, encompassing seismic activity, vibrations, bending moments, shear forces, and other key parameters, is wirelessly transmitted to the cloud where it can then be accessed and visualized using mobile app. The system offers real-time insights into the structural integrity of buildings and provides early warnings, thereby contributing significantly to reducing the risk of building collapses. Key findings show that when incorporated into an automated Structural Health Monitoring (SHM) system, the user's mobile app offers essential structural insights, capturing values such as a 0.5-unit vibration level, 20 units of shear force, 50 units of bending moment, and an 89-degree vertical wall angle. The app's userfriendly interface improves the effectiveness of monitoring and overseeing structural health, in line with the overarching objective of promoting safety in construction practices

Automated Structural Health Monitoring System for Mitigating Building Collapse in Nigeria: A Mobile App Approach

Abstract: Building collapses have become a distressing and recurring issue in Nigeria, necessitating urgent action to mitigate their occurrence. This paper introduces an innovative approach to address this challenge by developing an Automated Structural Health Monitoring System (ASHMS) utilizing a mobile app. Focusing on major cities like Lagos and Abuja, the proposed system employs strategically placed sensors to gather data from various structural elements of buildings. The collected information, encompassing seismic activity, vibrations, bending moments, shear forces, and other key parameters, is wirelessly transmitted to the cloud where it can then be accessed and visualized using mobile app. The system offers real-time insights into the structural integrity of buildings and provides early warnings, thereby contributing significantly to reducing the risk of building collapses. Key findings show that when incorporated into an automated Structural Health Monitoring (SHM) system, the user's mobile app offers essential structural insights, capturing values such as a 0.5-unit vibration level, 20 units of shear force, 50 units of bending moment, and an 89-degree vertical wall angle. The app's userfriendly interface improves the effectiveness of monitoring and overseeing structural health, in line with the overarching objective of promoting safety in construction practices.

ОЦЕНКА ТЕПЛОВОГО КОМФОРТА ДЕТЕЙ В ЖИЛЫХ И ОБЩЕСТВЕННЫХ ЗДАНИЯХ

In calculating children's thermal comfort, it is important to consider internal heat emissions, one of the main sources of which are the children themselves (heat exchange with the body surface, breathing, sweating). The accuracy of the calculation is influenced by their number, nature and intensity of activity, age, gender, and other parameters. Most regulatory documents base heat input calculations on a person with the following parameters: male, 20-30 years old, 70 kg, living in a temperate climate. This approach does not account for the physiological and age-specific characteristics of different age groups. The paper examines and refines the physiological parameters of children and uses models to numerically reflect the level of thermal comfort in a room. A calculation method is proposed that uses refined physiological parameters of children and evaluates thermal sensation of the indoor microclimate through the determination of Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD). Calculations of several microclimatic regimes were carried out, assessing the state of children of different ages and physical activity levels within the considered microclimate parameters. Analyzing the obtained data led to the conclusion that assessing human comfort using refined energy expenditures allows for a more flexible consideration of the thermal states of children in specific age groups. This enables higher quality regulation of the indoor microclimate of a specific room considering the examined factors.

Walnut Seed Coat (Juglans regia L.), a Plant Effective in Human Health: Antioxidant Activity and in Rats Nephroprotective Effect

In the study, the seed coat (WSC) of Posof (Ardahan/Türkiye) walnuts was extracted to determine their phytochemical components and antioxidant capacities. The effects of bioactive components in the ethanol extract of WSC (E-WSC) on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors were investigated. Additionally, antioxidant enzyme activity parameters were measured in the kidney tissues of Triton WR-1339-induced hyperlipidemic rats. Bioactive compounds in WSC were identified by GC-MS system. The antioxidant properties of WSC were measured using Fe+3, Cu+2 and Fe+3-2,4,6-tripyridyl-s-triazine (TPTZ) reducing agent, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'- azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activities. In this analysis, using 30 male Wistar rats (300 ± 30 g) randomly divided into five groups were treated as follows; K1: Healthy control group, K2: E-WSC (150 mg) o.d., K3: E-WSC (300 mg) o.d., K4: Hyperlipidemic group i.p., K5: Hyperlipidemic group i.p. + E-WSC (300 mg) o.d. Superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) analyzes were performed in kidney tissues. Based on these results, it was clearly determined that E-WSC has significant antioxidant activity due to its bioactive components, has an inhibitory effect on AChE and BChE enzymes, and has a protective effect against oxidative stress by improving hyperlipidemia-related kidney damage.

Sagittal spinal curvatures of young adults in the context of their self-reported physical activity and somatic parameters

The objective of this study was to assess the thoracic kyphosis (ThKA) and lumbar lordosis (LLA) in healthy young adults and to investigate potential relationships between spinal curvatures, self-reported physical activity (PA), and somatic parameters. The study included 380 female students and 211 male students aged 20.7 ± 1.5 years. The ThKA and LLA were measured using a Plurimeter-V gravity inclinometer. The level of PA was estimated using the International Physical Activity Questionnaire. ThKA was lower in women compared to men, while LLA was higher in women than in men (p < 0.0001). Female students reported lower PA than male students (p < 0.001). Female students with ThKA within normal values reported a significantly higher amount of low-intensity PA compared to those with ThKA below or above the norm. A correlation was found between ThKA and body mass index (BMI), body adiposity index (BAI), WC, and fat percentage (rho < 0.2), whereas LLA showed correlations with BMI, BAI, waist circumference, and fat percentage (rho < 0.2). Among male students, a correlation was found between LLA and BMI as well as WC (rho < 0.2). Maintaining a healthy body composition may be instrumental in mitigating the risk of developing spinal curvature abnormalities.

Low concentration adsorption of ammonia using metal halide loaded biogas residue-based carbon materials

Treating wastewater with elevated ammonia nitrogen levels in garbage treatment plants is a global concern, with blow-off recognized as an efficient process for nitrogen removal. However, this method generates low-concentration ammonia, presenting a challenge for adequate recovery. This study addresses this issue by impregnating metal halides onto K2CO3-activated biogas residue to create composite materials tailored for adsorbing low-concentration ammonia. We systematically investigated the impact of activation parameters, metal halide type, loading capacity, and environmental conditions on the adsorption properties of the materials. Notably, at an activation temperature of 700 °C, utilizing copper chloride with a loading capacity of 30 %, the material exhibited a saturation adsorption capacity of 29.32 mg/g for 200 ppm NH3, with a breakthrough time of 45.6 min, significantly surpassing the untreated sample and demonstrated excellent regeneration performance. SEM, BET, and FTIR analyses revealed that the material provided dispersion sites for metal halides, promoted the complexation of metal halides and ammonia and retained pores for ammonia diffusion, thereby enhancing adsorption efficiency. This innovative approach contributes to waste utilization and ensures efficient ammonia recovery through metal halide-ammonia complexation.

A Kinetic and Mechanistic Study of Ir (III)-Catalyzed Oxidation of Methionine by HCF (III) in an Aqueous Alkaline Medium

Introduction: The kinetic study of Ir (III) chloride-catalyzed oxidation of methionine by hexacyanoferrate (abbreviated as HCF) III ions in aqueous alkaline medium was performed spectrophotometrically at constant ionic strength of 0.5 moldm-3 and temperature of 35±0.10C. Method: The progress of the reaction was found to be first-order rate dependence kinetics with respect to [HCF (III)], [OH-], and [IrCl3]. The rate of reaction was found to decrease with an increased concentration of methionine. The ionic strength of the reaction mixture showed a positive salt effect on the reaction rate. Different activation parameters were also evaluated by studying the reaction at four different temperatures. The stoichiometry of the reaction showed Methionine: HCF (III) = 1:4. Result: The oxidation product of the reaction was found to be methionine sulphone, which was identified by an organic solvent method and IR Spectroscopy. Further, a suitable mechanism was proposed to explain all the experimental results. Conclusion: It is assumed that the reaction proceeded through complex formation between substrate (abbreviated) and iridium trichloride. A rate law was derived, which verified the results. CH3-S-(CH2)2-CH (NH2)-COO- + 4HCF (III) Ir (III), H2O CH3-SO2-(CH2)2-CH- (NH2)-COO- + 4HCF (II) result: 1.Methionine sulphone was found to be the main product of oxidation was identified using an organic solvent method and IR Spectroscopy. A suitable mechanism has been proposed to explain all the experimental results. It is assumed that reaction proceeds through complex formation between substrate (abbreviated) and iridium trichloride. A rate law has been derived which verifies the results. CH3 –S-(CH2)2-CH (NH2) – COO- + 4HCF (III) □(→┴(Ir(III),H2O) ) CH3-SO2-(CH2)2-CH (NH2)-COO- + 4HCF (II) 2. Degradation kinetic is anticipated to follow the first order kinetics at lower concentration. 3. The catalytic system can be recycled and reused without loss of activity. 4. The anticipated easy recovery of catalyst from the reaction mixture shows another positive signigficance.

Esaxerenone: blood pressure reduction and cardiorenal protection without reflex sympathetic activation in salt-loaded stroke-prone spontaneously hypertensive rats.

Mineralocorticoid receptor (MR) is involved in the mechanisms of blood pressure elevation, organ fibrosis, and inflammation. MR antagonists have been used in patients with hypertension, heart failure, or chronic kidney disease. Esaxerenone, a recently approved MR blocker with a nonsteroidal structure, has demonstrated a strong blood pressure-lowering effect. However, blood pressure reduction may lead to sympathetic activation through the baroreflex. The effect of esaxerenone on the sympathetic nervous system remains unclear. We investigated the effect of esaxerenone on organ damage and the sympathetic nervous system in salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP), a well-established model of essential hypertension with sympathoexcitation and organ damage. Three-week administration of esaxerenone or hydralazine successfully attenuated the blood pressure elevation. Both esaxerenone and hydralazine comparably suppressed left ventricular hypertrophy and urinary albumin excretion. However, renal fibrosis and glomerular sclerosis were suppressed by esaxerenone but not hydralazine. Furthermore, plasma norepinephrine level, a parameter of systemic sympathetic activity, was significantly increased by hydralazine but not by esaxerenone. Consistent with these findings, the activity of the control centers of sympathetic nervous system, the parvocellular region of the paraventricular nucleus in the hypothalamus and the rostral ventrolateral medulla, was enhanced by hydralazine but remained unaffected by esaxerenone. These results suggest that esaxerenone effectively lowers blood pressure without inducing reflex sympathetic nervous system activation. Moreover, the organ-protective effects of esaxerenone appear to be partially independent of its blood pressure-lowering effect. In conclusion, esaxerenone demonstrates a blood pressure-lowering effect without concurrent sympathetic activation and exerts organ-protective effects in salt-loaded SHRSP. Esaxerenone has antihypertensive and cardiorenal protective effects without reflex sympathetic activation in salt-loaded stroke-prone spontaneously hypertensive rats.

Variation in Activation Parameters for the Preparation of Cellulose-Based Porous Carbon Fibers Used for Electrochemical Applications

Variation in Activation Parameters for the Preparation of Cellulose-Based Porous Carbon Fibers Used for Electrochemical Applications

The impact of Activation on the Performance of Optical Oxygen Sensing with the Luminescent Metal–Organic Framework MOF‐76(Eu)

AbstractThe influence of activation as key parameter for oxygen sensing by luminescent metal–organic frameworks has been investigated and quantified for the archetype MOF‐76(Eu). Activation at different conditions (regarding temperature and solvent‐exchange for distinct vacuum pressure and heating time), shows an influence on the overall quenching, response time and cyclability due to different pore accessibility and surface area and therefore on the overall performance of the sensor. The optical sensing process is based on luminescence quenching, analyzed from high vacuum (10−7 bar) to ambient pressure by dosing oxygen from 0.01 bar to 1 bar. Strong influence of the different activation parameters is observed, as MOF‐76(Eu) activated at 50 °C shows limited quenching of the luminescence intensity within 30 min, while methanol‐exchange and subsequent activation at 250 °C leads to a quenching rate of 98.6 %. In addition, the sensor response occurs more than 1000 times faster within 0.2 s. These results correlate well with physisorption data, which reveal a significant change in porosity and surface area according to the degree of activation. For a better understanding of the involved processes, adsorption isotherms were recorded, surface areas determined and correlated to the photophysical parameters, including Stern‐Volmer kinetics and cycling experiments for the differently activated MOF sensors.

Possibilities of backward walking application in the rehabilitation of patients with gonarthrosis: review

INTRODUCTION. Osteoarthritis of the knee joint or gonarthrosis (GA) is one of the most common joint pathologies. The medical and social significance of GA is associated with its high prevalence and a significant percentage of premature disability and a significant deterioration in the quality of life due to persistent pain syndrome. Modern treatment of patients with GA includes a combination of pharmacological and non-pharmacological methods; physical therapy is the leading method of non-drug therapy. By now, a number of studies have been conducted to research the effectiveness of backward walking (BW) in people with GA. AIM. Analysis of scientific data on the possibilities of using BW in the rehabilitation of patients with GA. MATERIALS AND METHODS. A systematic search of literary sources by keywords was carried out: “backward walking”, “gonarthrosis”, “knee osteoarthritis”, “knee joint”, “rehabilitation”, “physical therapy”. DISCUSSION. Recently, backward locomotion is increasingly used in medicine. Kinetic and kinematic analysis during BW showed a number of advantages over the usual method of movement, which can be successfully used for rehabilitation of patients with GA. BW is associated with less overload on knee joints. It is also one of the few natural ways of strengthening the quadriceps. It prevents excessive stretching of the anterior cruciate ligament and improves the stability of the knee joint. BW leads to a more cardiovascular and respiratory load and a more significant aerobic and anaerobic capacity of the organism compared with forward walking at similar parameters of physical activity. CONCLUSION. There is evidence that adding BW to conventional physiotherapy treatment may further reduce pain, functional disability and improve the strength of the quadriceps muscles.

Mathematical Modeling Suggests That Monocyte Activity May Drive Sex Disparities during Influenza Infection.

In humans, females of reproductive age often experience a more severe disease during influenza A virus infection, which may be due to differences in their innate immune response. Sex-specific outcomes to influenza infection have been recapitulated in mice, enabling researchers to study viral and immune dynamics in vivo in order to identify immune mechanisms that are differently regulated between the sexes. This study is based on the hypothesis that sex-specific outcomes emerge due to differences in the rates/speeds that select immune components respond. Using publicly available sex-specific murine data, we utilized dynamic mathematical models of the innate immune response to identify candidate mechanisms that may lead to increased disease severity in female mice. We implemented a large computational screen using the Bayesian information criterion (BIC), wherein the goodness of fit of the competing model scenarios is balanced against complexity (i.e., the number of parameters). Our results suggest that having sex-specific rates for proinflammatory monocyte induction by interferon and monocyte inhibition of virus replication provides the simplest (lowest BIC) explanation for the difference observed in the male and female immune responses. Markov-chain Monte Carlo (MCMC) analysis and global sensitivity analysis of the top performing scenario were performed to provide rigorous estimates of the sex-specific parameter distributions and to provide insight into which parameters most affect innate immune responses. Simulations using the top-performing model suggest that monocyte activity could be a key target to reduce influenza disease severity in females. Overall, our Bayesian statistical and dynamic modeling approach suggests that monocyte activity and induction parameters are sex-specific and may explain sex-differences in influenza disease immune dynamics.

Predicting Individual Hearing-Aid Preference From Self-Reported Listening Experiences in Daily Life.

The study compared the utility of two approaches for collecting real-world listening experiences to predict hearing-aid preference: a retrospective questionnaire (Speech, Spatial, and Qualities of Hearing Scale [SSQ]) and in-situ Ecological Momentary Assessment (EMA). The rationale being that each approach likely provides different and yet complementary information. In addition, it was examined how self-reported listening activity and hearing-aid data-logging can augment EMAs for individualized and contextualized hearing outcome assessments. Experienced hearing-aid users (N = 40) with mild-to-moderate symmetrical sensorineural hearing loss completed the SSQ questionnaire and gave repeated EMAs for two wear periods of 2-weeks each with two different hearing-aid models that differed mainly in their noise reduction technology. The EMAs were linked to a self-reported listening activity and sound environment parameters (from hearing-aid data-logging) recorded at the time of EMA completion. Wear order was randomized by hearing-aid model. Linear mixed-effects models and Random Forest models with five-fold cross-validation were used to assess the statistical associations between listening experiences and end-of-trial preferences, and to evaluate how accurately EMAs predicted preference within individuals. Only 6 of the 49 SSQ items significantly discriminated between responses made for the end-of-trial preferred versus nonpreferred hearing-aid model. For the EMAs, questions related to perception of the sound from the hearing aids were all significantly associated with preference, and these associations were strongest in EMAs completed in sound environments with predominantly low SNR and listening activities related to television, people talking, nonspecific listening, and music listening. Mean differences in listening experiences from SSQ and EMA correctly predicted preference in 71.8% and 72.5% of included participants, respectively. However, a prognostic classification of single EMAs into end-of-trial preference with a Random Forest model achieved a 93.8% accuracy when contextual information was included. SSQ and EMA predicted preference equally well when considering mean differences, however, EMAs had a high prognostic classifications accuracy due to the repeated-measures nature, which make them ideal for individualized hearing outcome investigations, especially when responses are combined with contextual information about the sound environment.

Classification of Major Solar Flares from Extremely Imbalanced Multivariate Time Series Data Using Minimally Random Convolutional Kernel Transform

Solar flares are characterized by sudden bursts of electromagnetic radiation from the Sun’s surface, and are caused by the changes in magnetic field states in active solar regions. Earth and its surrounding space environment can suffer from various negative impacts caused by solar flares, ranging from electronic communication disruption to radiation exposure-based health risks to astronauts. In this paper, we address the solar flare prediction problem from magnetic field parameter-based multivariate time series (MVTS) data using multiple state-of-the-art machine learning classifiers that include MINImally RandOm Convolutional KErnel Transform (MiniRocket), Support Vector Machine (SVM), Canonical Interval Forest (CIF), Multiple Representations Sequence Learner (Mr-SEQL), and a Long Short-Term Memory (LSTM)-based deep learning model. Our experiment is conducted on the Space Weather Analytics for Solar Flares (SWAN-SF) benchmark data set, which is a partitioned collection of MVTS data of active region magnetic field parameters spanning over nine years of operation of the Solar Dynamics Observatory (SDO). The MVTS instances of the SWAN-SF dataset are labeled by GOES X-ray flux-based flare class labels, and attributed to extreme class imbalance because of the rarity of the major flaring events (e.g., X and M). As a performance validation metric in this class-imbalanced dataset, we used the True Skill Statistic (TSS) score. Finally, we demonstrate the advantages of the MVTS learning algorithm MiniRocket, which outperformed the aforementioned classifiers without the need for essential data preprocessing steps such as normalization, statistical summarization, and class imbalance handling heuristics.

Photo-Oxidation of α-Pinene Oxidation Products in Atmospheric Waters - pH- and Temperature-Dependent Kinetic Studies.

The atmospheric α-pinene oxidation leads to three carboxylic acids: norpinonic acid (NPA), pinic acid (PA), and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA). In this study, the OH radical kinetics in the aqueous phase of these carboxylic acids were investigated at different temperatures and pH values of solutions. Activation parameters and the corresponding atmospheric lifetimes of the acids in the troposphere were derived. The overall second-order rate constants for the individual speciation forms of the acids (AH and A- for NPA; AH2, AH- and A2- for PA; and AH3, AH2-, AH2- and A3- for MBTCA) were determined. At 298 K, the rate constants for reactions of protonated forms (AHx) of NPA, PA, and MBTCA with •OH, were (1.5 ± 0.2) × 109 L mol-1 s-1, (2.4 ± 0.1) × 109 L mol-1 s-1, and (4.1 ± 0.6) × 108 L mol-1 s-1, respectively. For the fully deprotonated forms (Ax-) of studied acids, the second-order rate constants were (2.2 ± 0.2) × 109 L mol-1 s-1, (2.8 ± 0.1) × 109 L mol-1 s-1, and (10.2 ± 0.7) × 108 L mol-1 s-1 at 298 K, respectively. It was found that the reactions of NPA and PA with OH radicals are faster than with MBTCA. For MBTCA, the reaction rate depends on pH more strongly at elevated temperatures (>298 K). The atmospheric lifetimes of the acids considered due to their reactivity with •OH were calculated for different model scenarios at a temperature of 283 K and pH = 2 in the aqueous phase. For this purpose, liquid water content (LWC) was used for aerosols and clouds under storm conditions and at various aqueous-phase concentrations of OH radicals. The lifetimes decreased with increasing LWC (from 10-12 m3 m-3 in aerosol to 10-5 m3 m-3 in storms), indicating that the acids undergo significant aqueous processing under realistic atmospheric conditions. Besides, the aerosol systems appeared less effective in removing PA and NPA, with lifetimes ranging from hundreds of days to tens and hundreds of hours, respectively. Clouds were more effective, with lifetimes ranging from tens of hours to a single second or less. MBTCA, which dissolves better in water, was effectively removed in all systems, with the longest lifetime of approximately 90 min.

Preparation of amorphous coal-based activated coke via a two-step process of carbonization and steam activation

The coal-based activated coke (AC) is suitable for desulfurization and denitrification in coal-fired power plants. However, the current studies on millimeter-sized amorphous AC are limited. To evaluate the preparation parameters of millimeter-sized amorphous AC, two typical middle-low rank coal samples, Fugu coal and Datong coal, are selected as the raw materials. The effects of carbonization/activation parameter, particle size and steam flow rate on the yield and pore structure of AC are studied. Samples are analyzed by the synchronous thermal analyzer and the fully automatic rapid specific surface and porosity analyzer. The results show that carbonization and the long-time steam activation at a low temperature can make the internal pores of samples fully developed, significantly increasing the specific surface area and pore volume. The coke yield, specific surface area and mesoporous proportion of Fugu AC obtained by activation at 700 °C for 3 h are 60.95 %, 429.54 m2/g and 29.60 %, respectively. The corresponding values of Datong AC obtained at 850 °C for 3 h are 53.19 %, 892.20 m2/g and 23.01 %, separately. Both of Fugu AC and Datong AC belong to the hierarchical porous AC. The influence of particle sizes on the performance of AC at the millimeter level is within the acceptable range. Therefore, the same carbonization and activation parameters can be chosen to prepare Fugu AC and Datong AC with different particle sizes, respectively. The water vapor flow rate has a significant effect on the pore structure of AC. There is a moderate flow rate (0.03 mL min−1 at this study’s experimental conditions) for preparing the hierarchical porous amorphous AC. The study shows that it is feasible to prepare the amorphous AC with the hierarchical pore structure by employing the millimeter-sized medium–low rank coal particles. The AC could be applied for the pollutants removal in the coal-fired power plants.