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During the last decade, the hydrate-based CO2 capture (HBCC) process has been approved as a promising alternative. The HBCC offers several attractive advantages such as the mild operating pressure and temperature, the ease of regeneration of CO2, and its low energy consumption. The HBCC is at its infancy stage where the numerical methods play a key role in its research and development. This is to support the experimental research in terms of the model-based experiment design and process analysis/optimisation. In this view, HBCC modelling and simulation have been focused by researchers worldwide. Most of the published models are restricted to the processes at the particle scale that are enormously beneficial for a fundamental understanding of the process science. Nevertheless, a challenging shortfall currently exists for reactor scale models given the process scale research, and development objectives require models at the relevant scale. Accordingly, the reactor level models that may be used in a comprehensive process are required. Ideally, a multi-scale model allows studying both science and technology. This paper presents an HBCC process model at the reactor level for batch and semi-batch operations. The scaled-up model is capable of simulating the CO2 dissolution, and growth phases. The model evaluates the hydrate layer boundary and estimates the total gas uptake in batch semi-batch reactors. A modified version of the model made it possible to account. The present study establishes a groundwork for the large-scale application of the HBCC.

The hydrate-based carbon dioxide (CO2) capture (HBCC) process has been widely studied for CO2 separation and sequestration. This paper aims to conduct a model-based investigation of the kinetics of the HBCC process. A variation of the shrinking core model (SCM) was developed for the analysis of this heterogeneous system under varying boundary conditions. The results revealed that while CO2 diffusion through the hydrate layer is the dominant controlling mechanism, for a realistic scenario in which a time-dependent bulk gas concentration exists, the model results would better match the experimental data if the effects of the reaction rate were incorporated into the diffusion-based model. Sensitivity analysis showed that increasing the diffusivity through the hydrate layer significantly decreases the full conversion time of the water. Moreover, the effect of temperature change was investigated, and it was found that lower temperatures slow the hydrate growth rate. The model was demonstrated to be a computationally effective and time-efficient predictive tool that does not require high-speed computers for large-scale (reactor) applications.

Background: In Iranian traditional medicine, gum obtained from Astragalus gummifer and some other species of Astragalus was used as analgesic agent. Objective: In this study, we investigated the antinociceptive effect of several concentrations (125, 250, and 500 μg/kg body weight) of Astragalus gummifer gum (AGG) on thermal and acetic acid induced pain in mice. Materials and Methods: AGG was dissolved in distillated water and injected i.p to male mice 15 minute before the onset of experiment. Writhing and hot-plate tests were applied to study the analgesic effect of AGG and compared with that of diclofenac sodium (30 mg/kg, i.p.) or morphine (8 mg/kg, i.p). To investigate the mechanisms involved in antinociception, yohimbine, naloxone, glibenclamide, and theophylline were used in writhing test. These drugs were injected intraperitoneally 15 min before the administration of AGG. The number of writhes were counted in 30 minutes and analyzed. Results: AGG exhibited a significant antinociceptive effect and the most effective dose of AGG was 500 μg/kg. The most maximum possible effect (%MPE) was observed (117.4%) 15 min after drug administration. The %inhibition of acetic acid-induced writhing in AGG 125, 250 and 500 was 47%, 50% and 54% vs %15 of control and 66.3% of diclofenac sodium group. The antinociceptive effect induced by this gum in the writhing test was reversed by the systemic administration of yohimbine (α 2 -adrenergic antagonist), but naloxone, glibenclamide, and theophylline did not reverse this effect. Conclusions: The findings of this study indicated that AGG induced its antinociceptive through the adrenergic system.

Background: In Ayurveda and traditional medicines of different countries such as Iran, America and Brazil, asafoetida has been used as an aphrodisiac agent. Objective: The present study was aimed to evaluate the effectiveness of asafoetida on spermatic and testicular parameters in treated rats. Materials and Methods: A total of 30 male Wistar rats divided equally to five groups (one control and four test groups receiving 25, 50,100 and 200 mg/kg asafoetida respectively). After 6 weeks, a small part of the cauda epididymis of each rat was dissected, and the spermatic parameters were evaluated for at least 200 spermatozoa of each animal. Testis of all rats was harvested for pathologic examination. The testosterone concentration of serum was also determined. Data were statistically assessed by one-way ANOVA and value of P < 0.05 was considered as the level of significance. Results: This study indicated that the asafoetida significantly increased the number and viability of sperms (P < 0.05). Histological study showed that spermatogenesis process and numbers of Leydig cells were increased with increasing the dose, but the Leydig cells become vacuolated. Johnsen score in experimental groups was increased compared to control although this difference was not significant (P > 0.05). Conclusion: Asafoetida showed a positive effect on spermatic parameters although the histopathological effects on the testis were observed, particularly at high doses.