scholarly journals BRUCITE-BASED MAGNESIUM PHOSPHATE BONDING AGENT, ITS ANALYSIS AND APPLICATION FOR PERICLASE SINTERING

2019 ◽  
Vol 62 (12) ◽  
pp. 119-124
Author(s):  
Nadezhda F. Kosenko ◽  
Natalya V. Filatova ◽  
Maxim A. Glazkov
Keyword(s):  
Activation Energy ◽  
Weight Loss ◽  
Phase Composition ◽  
Crystalline Hydrate ◽  
Magnesium Phosphate ◽  
Kinetics Parameters ◽  
Weight Losses ◽  
Exothermal Effect ◽  
Phosphate Bonding ◽  
Sample Weight Loss

Some results on magnesium phosphate binder obtained from natural brucite (mainly Mg(OH)2) and H3PO4 were discussed. Hereafter, it was named brucite phosphate (BPB). This binder then was used to the sintering of MgO (periclase). MgO is one of the most high-refractory materials and chemically stable to various aggressive mediums, so the aim was presented as actual. To determine the phase composition data on sample weight loss in different temperature intervals were compared. All weight losses were related to the multistage water moving away. Up to 140 °С it was the removal of crystalline hydrate water. Then monosubstituted magnesium hydrophosphate transformed into MgH2P2O7 and Mg2P4O12, that in principle was in accordance with literature data. Dehydration was accompanied with appropriate endothermal effects. There was a slight exothermal effect which could relate to a structure rearrangement (cyclization) of primary magnesium metaphosphates and/or some crystallization of anhydrous cyclophosphates from primarily obtained amorphous phase non-connected with a weight loss in the interval of 450-575 °С. At 500–1000 °С the phase composition remained constant that was in a good accordance with data obtained by other methods. By means of IR-spectroscopy, it was confirmed the formation of structure cycles composed from oxygen-phosphor tetrahedrons. To determine kinetics parameters of periclase sintering with BPB it was used a model being proposed that took the role of a physical consolidation and a chemical binding in the presence of binder into account under heating. The obtained parameters analysis showed that the forming conglomerate strength was provided with the sintering properly as well as with binder action; an estimated chemical factor contribution was maximal at low temperatures (1100-1200 °C). The activation energy value was practically identical to the activation energy of oxygen diffusion in MgO.

On the use of Ozawa/Flynn/Wall method to determine aging activation energy for elastomers

2021 ◽  
pp. 009524432110203
Author(s):  
Sudhir Bafna
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Weight Loss ◽  
Oxygen Consumption ◽  
Dwell Time ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Degradation Mechanism ◽  
Kinetics Of ◽  
Wall Method

It is often necessary to assess the effect of aging at room temperature over years/decades for hardware containing elastomeric components such as oring seals or shock isolators. In order to determine this effect, accelerated oven aging at elevated temperatures is pursued. When doing so, it is vital that the degradation mechanism still be representative of that prevalent at room temperature. This places an upper limit on the elevated oven temperature, which in turn, increases the dwell time in the oven. As a result, the oven dwell time can run into months, if not years, something that is not realistically feasible due to resource/schedule constraints in industry. Measuring activation energy (Ea) of elastomer aging by test methods such as tensile strength or elongation, compression set, modulus, oxygen consumption, etc. is expensive and time consuming. Use of kinetics of weight loss by ThermoGravimetric Analysis (TGA) using the Ozawa/Flynn/Wall method per ASTM E1641 is an attractive option (especially due to the availability of commercial instrumentation with software to make the required measurements and calculations) and is widely used. There is no fundamental scientific reason why the kinetics of weight loss at elevated temperatures should correlate to the kinetics of loss of mechanical properties over years/decades at room temperature. Ea obtained by high temperature weight loss is almost always significantly higher than that obtained by measurements of mechanical properties or oxygen consumption over extended periods at much lower temperatures. In this paper, data on five different elastomer types (butyl, nitrile, EPDM, polychloroprene and fluorocarbon) are presented to prove that point. Thus, use of Ea determined by weight loss by TGA tends to give unrealistically high values, which in turn, will lead to incorrectly high predictions of storage life at room temperature.

Application of Calculus Equation in Solving Thermal Decomposition Kinetics Parameters of Flame Retardant Wood

2014 ◽  
Vol 983 ◽  
pp. 190-193
Author(s):  
Cai Yun Sun ◽  
Yong Li Yang ◽  
Ming Gao
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Phosphoric Acid ◽  
Flame Retardant ◽  
Kinetic Parameters ◽  
Flame Retardancy ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Kinetics Parameters

Wood has been treated with amino resins and amino resins modified with phosphoric acid to impart flame retardancy. The thermal degradation of samples has been studied by thermogravimetry (TG) in air. From the resulting data, kinetic parameters for different stages of thermal degradation are obtained following the method of Broido. For the decomposition of wood and flame retardant wood, the activation energy is found to decrease from 122 to 72 kJmol-1.

scholarly journals Session 3 (Joint with the British Dietetic Association): Management of obesity Weight-loss interventions in the treatment of obesity

2009 ◽  
Vol 69 (1) ◽  
pp. 34-38 ◽  
Author(s):  
C. R. Hankey
Keyword(s):  
Physical Activity ◽  
Weight Loss ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Weight Maintenance ◽  
Dietary Advice ◽  
Excess Body Weight ◽  
Lifestyle Interventions ◽  
Post Intervention ◽  
Weight Losses

Treatments to induce weight loss for the obese patient centre on the achievement of negative energy balance. This objective can theoretically be attained by interventions designed to achieve a reduction in energy intake and/or an increase in energy expenditure. Such ‘lifestyle interventions’ usually comprise one or more of the following strategies: dietary modification; behaviour change; increases in physical activity. These interventions are advocated as first treatment steps in algorithms recommended by current clinical obesity guidelines. Medication and surgical treatments are potentially available to those unable to implement ‘lifestyle interventions’ effectively by achieving losses of between 5 kg and 10 kg. It is accepted that the minimum of 5% weight loss is required to achieve clinically-meaningful benefits. Dietary treatments differ widely. Successful weight loss is most often associated with quantification of energy intake rather than macronutrient composition. Most dietary intervention studies secure a weight loss of between 5 kg and 10 kg after intervention for 6 months, with gradual weight regain at 1 year where weight changes are 3–4 kg below the starting weight. Some dietary interventions when evaluated at 2 and 4 years post intervention report the effects of weight maintenance rather than weight loss. Specific anti-obesity medications are effective adjuncts to weight loss, in most cases doubling the weight loss of those given dietary advice only. Greater physical activity alone increases energy expenditure by insufficient amounts to facilitate clinically-important weight losses, but is useful for weight maintenance. Weight losses of between half and three-quarters of excess body weight are seen at 10 years post intervention with bariatric surgery, making this arguably the most effective weight-loss treatment.

scholarly journals Influence of sodium carbonate addition on weight loss of bagasse alkaline black liquor during pyrolysis

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2428-2441
Author(s):  
Xusheng Li ◽  
Jinlong Wang ◽  
Derong Yan ◽  
Yongjun Yin ◽  
Shuangfei Wang
Keyword(s):  
Activation Energy ◽  
Weight Loss ◽  
Sodium Carbonate ◽  
Black Liquor ◽  
Reduction Reaction ◽  
Loss Ratio ◽  
N2 Atmosphere ◽  
Microscopic Morphology ◽  
Weight Loss Ratio

To understand the effects and the mechanism of sodium carbonate (Na2CO3) addition on the bagasse alkaline black liquor (BABL) pyrolysis, the reaction variables such as temperature, heating rate, and amount of Na2CO3 addition into BABL-solids were investigated under N2 atmosphere from 50 °C to 1000 °C by thermogravimetic analysis (TGA). Scanning electron microscopy (SEM) and the Coats–Redfern method (CRM) were employed for surface microscopic morphology observations and kinetic analysis, respectively. The results showed that Na2CO3 plays an inhibiting and promoting role during devolatilization (200 °C to 650 °C) and the reduction stages (650 °C to 1000 °C), respectively. Adding Na2CO3 into BABL-solids tends to increase the thickness of the salt layer covering the BABL-solids surface, which increases the activation energy and reduces the weight loss ratio of BABL-solids pyrolysis within 200 °C to 650 °C. Adding Na2CO3 into the BABL-solids tends to increase the number of alkaline compounds or the active site of the reduction reaction, which reduces the activation energy and increases the weight loss ratio of BABL-solids pyrolysis within 650 °C to 1000 °C. The role of Na2CO3 as an additive could be well understood by studying the influence mechanism of Na2CO3 on BABL-solids pyrolysis.

scholarly journals Telemedical Coaching Improves Long-Term Weight Loss in Overweight Persons: A Randomized Controlled Trial

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kerstin Kempf ◽  
Martin Röhling ◽  
Monika Stichert ◽  
Gabriele Fischer ◽  
Elke Boschem ◽  
...  
Keyword(s):  
Health Care ◽  
Weight Loss ◽  
Occupational Health ◽  
Care Setting ◽  
Health Care Setting ◽  
Control Group ◽  
Lifestyle Interventions ◽  
Occupational Health Care ◽  
Weight Losses

Background. Lifestyle interventions have shown to be effective when continuous personal support was provided. However, there is lack of knowledge whether a telemedical-approach with personal coaching contributes to long-term weight losses in overweight employees. We, therefore, tested the hypothesis that telemedical-based lifestyle interventions accompanied with telemedical coaching lead to larger weight losses in overweight persons in an occupational health care setting. Methods. Overweight employees (n=180) with a body mass index (BMI) of >27 kg/m2 were randomized into either a telemedical (TM) group (n=61), a telemedical coaching (TMC) group (n=58), or a control group (n=61). Both intervention groups were equipped with scales and pedometers automatically transferring the data into a personalized online portal, which could be monitored from participants and coaches. Participants of the TMC group received additionally one motivational care call per week by mental coaches to discuss the current data (current weight and steps) and achieving goals such as a healthy lifestyle or weight reduction. The control group remained in routine care. Clinical and anthropometric data were determined after the 12-week intervention. Additionally, weight change was followed up after 12 months. Results. Participants of TMC (-3.1 ± 4.8 kg, p<0.0001) and TM group (-1.9 ± 4.0 kg; p=0.0012) significantly reduced weight and sustained it during the 1-year follow-up, while the control group showed no change. Compared to the control group only weight loss in the TMC group was significantly different (p<0.001) after 12 months. TMC and TM group also reduced BMI, waist circumference, and LDL cholesterol. Moreover, TMC group improved additionally systolic and diastolic blood pressure, total cholesterol, HDL cholesterol, and HbA1c. Conclusions. Telemedical devices in combination with telemedical coaching lead to significant long-term weight reductions in overweight persons in an occupational health care setting. This study is registered with NCT01868763, ClinicalTrials.gov.

BestFIT Sequential Multiple Assignment Randomized Trial Results: A SMART Approach to Developing Individualized Weight Loss Treatment Sequences

2021 ◽  
Author(s):  
Nancy E Sherwood ◽  
A Lauren Crain ◽  
Elisabeth M Seburg ◽  
Meghan L Butryn ◽  
Evan M Forman ◽  
...  
Keyword(s):  
Weight Loss ◽  
Randomized Trial ◽  
Controlled Trial ◽  
Response Assessment ◽  
Optimal Time ◽  
Behavioral Weight Loss ◽  
Weight Loss Treatment ◽  
Adaptive Intervention ◽  
Weight Losses ◽  
Multiple Assignment

Abstract Background State-of-the-art behavioral weight loss treatment (SBT) can lead to clinically meaningful weight loss, but only 30–60% achieve this goal. Developing adaptive interventions that change based on individual progress could increase the number of people who benefit. Purpose Conduct a Sequential Multiple Assignment Randomized Trial (SMART) to determine the optimal time to identify SBT suboptimal responders and whether it is better to switch to portion-controlled meals (PCM) or acceptance-based treatment (ABT). Method The BestFIT trial enrolled 468 adults with obesity who started SBT and were randomized to treatment response assessment at Session 3 (Early TRA) or 7 (Late TRA). Suboptimal responders were re-randomized to PCM or ABT. Responders continued SBT. Primary outcomes were weight change at 6 and 18 months. Results PCM participants lost more weight at 6 months (−18.4 lbs, 95% CI −20.5, −16.2) than ABT participants (−15.7 lbs, 95% CI: −18.0, −13.4), but this difference was not statistically significant (−2.7 lbs, 95% CI: −5.8, 0.5, p = .09). PCM and ABT participant 18 month weight loss did not differ. Early and Late TRA participants had similar weight losses (p = .96), however, Early TRA PCM participants lost more weight than Late TRA PCM participants (p = .03). Conclusions Results suggest adaptive intervention sequences that warrant further research (e.g., identify suboptimal responders at Session 3, use PCMs as second-stage treatment). Utilizing the SMART methodology to develop an adaptive weight loss intervention that would outperform gold standard SBT in a randomized controlled trial is an important next step, but may require additional optimization work. Clinical Trial information ClinicalTrials.gov identifier; NCT02368002

Is there any conclusive evidence that exercise alone reduces glucose intolerance?

2003 ◽  
Vol 3 (1_suppl) ◽  
pp. S18-S23
Author(s):  
Arne Astrup
Keyword(s):  
Weight Loss ◽  
Diabetes Prevention ◽  
Intervention Studies ◽  
Conclusive Evidence ◽  
Regular Exercise ◽  
Metabolic Function ◽  
Weight Losses ◽  
Diet And Exercise ◽  
Obese Subjects

Physical activity improves insulin sensitivity and glucose metabolism, although such effects are short-lasting and regular exercise is needed to sustain them. Weight loss, especially loss of visceral fat, appears to be especially important in improving metabolic function and clinical outcomes. The most important consequences of exercise are probably promotion of weight loss and prevention of weight gain. Substantial weight losses, associated with significant improvements in glycaemic control and reductions in the incidence of type 2 diabetes, have been observed in intervention studies in overweight or obese subjects. These benefits were achieved using intensive lifestyle interventions, pharmacotherapy or surgery. Thus, programmes of diet and exercise aimed at achieving control of body weight should play a central role in strategies for diabetes prevention.

scholarly journals THE KINETICS OF CaO ASSISTED PATTUKKU CHARCOAL STEAM GASIFICATION

REAKTOR ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 16
Author(s):  
Takdir Syarif ◽  
H Sulistyo ◽  
Wahyudi B Sediawan ◽  
B Budhijanto
Keyword(s):  
Activation Energy ◽  
Tubular Reactor ◽  
Steam Gasification ◽  
Effect Of Temperature ◽  
Composition Analysis ◽  
Zone Model ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Surface Diffusivity ◽  
Gasification Process

Abstract Coal is a solid fuel that can be converted into syngas through gasification process. To obtain optimum gasification process design and operation, in-depth understanding of the influential parameters is required. This study aims to investigate the effect of temperature on the gasification process and to obtain its kinetics parameters. The study was carried out in a tubular reactor equipped with a heater and a condenser. Steam was used as gasifying agent, while CaO was employed as a CO2 adsorbent. The charcoal from coal was subjected to gasification at temperatures of 600°C, 700°C, and 800°C. The ratio of charcoal and CaO was 1:1. The gasification process lasted for 60 minutes with gas sample was taken every 15 minutes for composition analysis. The results showed that a temperature increase of 100°C caused a proportional increase of conversion of about 75% higher. The value of activation energy (Ea) and exponential factor (ko) were 46.645kJ/mole and 328.3894/min, respectively. For mass transfer parameters, values of activation energy for surface diffusion (Es) and surface diffusivity factor (as) were 81.126 kJ/mole and 0.138/min, respectively. Keywords: gasification; mathematical model; Pattukku coal char; steam; Thin Reaction Zone Model

scholarly journals Thermal decomposition characteristics of foundry sand for cast iron in nitrogen atmosphere

2018 ◽  
Vol 5 (12) ◽  
pp. 181091 ◽  
Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Xiwen Yao ◽  
Jishuo Li ◽  
Li Li
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Cast Iron ◽  
Low Cost ◽  
Temperature Stability ◽  
Nitrogen Atmosphere ◽  
High Temperature Stability ◽  
Kinetics Parameters ◽  
Foundry Sand ◽  
Exponential Factor

Sand casting, currently the most popular approach to the casting production, has wide adaptability and low cost. The thermal decomposition characteristics of foundry sand for cast iron were determined for the first time in this study. Thermogravimetry was monitored by simultaneous thermal analyser to find that there was no obvious oxidation or combustion reaction in the foundry sand; the thermal decomposition degree increased as the heating rate increased. There was an obvious endothermic peak at about 846 K due to the transition of quartz from β to α phase. A novel technique was established to calculate the starting temperature of volatile emission in determining the volatile release parameter of foundry sand for cast iron. Foundry sand does not readily evaporate because its volatile content is only about 2.68 wt% and its main components have high-temperature stability. The thermal decomposition kinetics parameters of foundry sand, namely activation energy and pre-exponential factor, were obtained under kinetics theory. The activation energy of foundry sand for cast iron was small, mainly due to the wide temperature range of thermal decomposition in the foundry sand.

Physiological and behavioral responses to starvation in the golden hamster.

1979 ◽  
Vol 236 (2) ◽  
pp. E105 ◽  
Author(s):  
K T Borer ◽  
N Rowland ◽  
A Mirow ◽  
R C Borer ◽  
R P Kelch
Keyword(s):  
Fatty Acids ◽  
Weight Loss ◽  
Weight Gain ◽  
Food Intake ◽  
Behavioral Responses ◽  
Blood Metabolites ◽  
Serum Concentrations ◽  
Weight Losses ◽  
Beta Hydroxybutyrate ◽  
Access To Food

Physiological and behavioral responses of adult hamsters to starvation were studied by measuring food intake, weight recovery, serum concentrations of glucose, insulin, free fatty acids and beta-hydroxybutyrate, and ketonuria in animals subjected to different weight losses, diets, and durations of fast. Hamsters were debilitated by fasts longer than 12 h or leading to greater than 20% weight loss. Hamsters' feeding patterns were unmodified by fasts ranging between 5 and 12 h and showed no circadian periodicity. Hamsters predominantly recovered from weight losses without increasing their food consumption (unless they were offered a diet of pellets and seeds) and without changing their meal patterns, at a rate of weight gain proportional to the magnitude of preceding weight loss if provided with uninterrupted access to food. By 8 h of fast, blood metabolites were indicative of mobilization of body fat. Hamsters are thus behaviorally unresponsive to duration of fast, but compensate physiologically for weight losses with proportional increases in the rate of weight gain.

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