Modeling Flame Propagation of Coal Char Particles in Heterogeneous Media

In the present research, combustion of a quiescent coal char particle cloud has been studied in the media with spatially discrete sources by means of numerical approach. A thermal model based on diffusion-controlled regime of coal char particles has been generated in order to estimate the characteristics of flame propagation in heterogeneous media. The model uses discrete heat sources to analyze dust combustion of particles with the diameter of 50 μm. Oxygen and Nitrogen have been considered as the main oxidizer and the inert gas, respectively. Flame propagation speed in various dust and oxygen concentrations has been studied. Flame speed as a function of particle size has been investigated and comparison between cases with and without consideration of radiation effect has been made. Furthermore, minimum ignition energy as a function of dust concentration for different particle sizes has been studied. Results show a reasonable compatibility with the existing experimental data

Study on hybrid combustion of aero-suspensions of boron-aluminum powders in a quiescent reaction medium

© 2017. The present research deals with a hybrid combustion of aluminum/boron dust particles in a heterogeneous quiescent reaction medium with spatially discrete heat sources. A developed thermal model is employed to estimate flame propagation speed in a reaction medium. The burning velocity and minimum ignition energy are studied parametrically as a function of dust concentration and particle diameter for different percentages of boron powder in a hybrid mixture of aluminum/boron dust cloud. The model shows that the addition of boron powder as a component of the mixture decreases the burning rate and causes a higher amount of minimum ignition energy needed for ignition, owing to the role of boron as a heat sink. Comparison of the simulation results with the available experimental data shows that the model captures the flame propagation speed as a function of particle concentration, except at very low concentrations

Survey of nutritional and economic values of bighead (Hypophthalmichthys nobilis) in various sizes

Cultured fish are presented in various sizes and prices in market. The present study aimed to investigate the proportion of nutritional value and price of various weight groups of bighead (Hypophthalmichthys nobilis) and to offer two indices for comparing nutritional value in proportion with fish prices. For this purpose, bighead specimens were prepared in market sizes and their dry matter, lipid, protein and ash content and fillet yield were determined. Then, the proportion of nutritional and financial value (NP) and justified price difference based on dry matter content (PDdm) were calculated for each weight group. The results showed that the light weight group has a higher NP index for dry matter, protein, ash and energy than medium and heavy weight group. The NP index was the same between medium and heavy groups. While the price difference between light weight and two other weight groups is more than calculated PDdm index, the light weight group is a proper choice for purchase

Identification of differential expressed transcripts of almond (Prunus dulcis ‘Sefied’) in response to water-deficit stress by cDNA-AFLP

Drought is the major abiotic stress with adverse effects on growth and productivity of plants. It induces the expression of various genes that are involved in stress response and tolerant/sensitive phenotypes. In this study, the expression of several genes were analyzed in response to dehydration in almond (Prunus dulcis 'Sefied') to shed light on the underlying genetic basis of water-deficit tolerance in almond. The advantages of using almond as a model system for studying dehydration tolerance in woody species are its small diploid genome and its adaptation to drought. Differential expression technique, cDNA-AFLP (amplified fragment length polymorphism), was used to find transcripts accumulated in young trees subjected to water-deficit treatment. Twenty transcript-derived fragments (TDFs) with differential expression between control and stress conditions were generated, amplified, and sequenced. The TDFs showing high homology with genes having known functions were validated by quantitative real-time PCR and their possible function(s) were discussed. These genes include: 2-deoxyglucose-6-phosphate phosphatase, protein kinase MK5 (AFC2) and urease, which up-regulated by 1.61, 2.39 and 4.87 fold under the water-deficit stress condition, respectively. In addition, network analysis unraveled a drought response mechanism displaying activation of the ABA signaling pathway via phosphorylation by 2-deoxyglucose-6-phosphate phosphatase and protein kinase MK5. Protein kinase MK5 was found to be a central element in the drought response network, displaying numerous interactions with RNA-splicing proteins, the sugar-mediated signaling pathway and an epigenetics response (histone phosphorylation).Maryam Shirani Bidabadi, Behrouz Shiran, Hossein Fallahi, Fariba Rafiei, Fazileh Esmaeili & Esmaeil Ebrahimi

Comparison of Thymus vulgaris (Thyme), Achillea millefolium (Yarrow) and propolis hydroalcoholic extracts versus systemic glucantime in the treatment of cutaneous leishmaniasis in balb/c mice

Background & objectives: Leishmaniasis is a parasitic disease transmitted by sand flies. Many investigations are performed to find an effective and safe treatment for leishmaniasis. In this study, we evaluated the efficacy of herbal extracts of Thymus vulgaris (Thyme) and Achillea millefolium (Yarrow), propolis hydroalcoholic extract and systemic glucantime against cutaneous leishmaniasis in Balb/c mice. Methods: A total of 45 mice were randomised into five groups each including nine mice. They were treated with pure ethanol 70°, systemic glucantime, Achillea millefolium hydroalcoholic extract, Thymus vulgaris hydroalcoholic extract and propolis hydroalcoholic extract for six weeks. The statistical tests including student t-test were used for analysis. Data were analyzed by SPSS software, ver 13.00. Results: Mean of ulcer size reduction were –17.66, –22.57, 43.29, 36.09 and 43.77% for the alcohol, glucantime, yarrow, thyme and propolis groups, respectively. The results were suggestive that Thymus vulgaris, Achillea millefolium and propolis hydroalcoholic extracts were significantly more effective in reduction of ulcer size as compared with glucantime (p = 0.006, 0.002 and 0.008, respectively). Interpretation & conclusion: Our results are suggestive that Thymus vulgaris, Achillea millefolium and propolis extracts are effective for treatment of cutaneous leishmaniasis in mice. Regarding these results, we suggest that efficacy of these extracts alone or in combination are evaluated against human cutaneous leishmaniasis as a randomized clinical trial

NRAMP1 gene polymorphisms and cutaneous leishmaniasis: An evaluation on host susceptibility and treatment outcome

Background & objectives: Association between polymorphisms in the natural resistance associated macrophage protein 1 (NRAMP1) gene and susceptibility to cutaneous leishmaniasis (CL) has been demonstrated worldwide; however, the reported results were inconsistent. This study aimed to determine the association of NRAMP1 variants with susceptibility to CL infection and patients� response to treatment in Isfahan province of Iran. Methods: Peripheral blood samples were collected from 150 patients with CL and 136 healthy controls. The CL patients were treated with intralesional injection of meglumine antimoniate. The polymorphic variants at NRAMP1 (A318V and D543N) were analyzed using PCR-RFLP. The chi-square test and Fisher�s exact test were used to compare frequencies of alleles and genotypes of polymorphisms between patient and healthy control populations. Results: There was a statistically significant difference in the D543N (rs17235409) polymorphism between the CL patients and healthy controls (p=0.008). However, no significant association was detected for A318V (rs201565523) polymorphism between groups (p=0.26). In addition, there was a lack of association between D543N and A318V genotypes with response to treatment (p=0.54 and p=0.31, respectively). Interpretation & conclusion: The results indicated that genetic variations of D543N (rs17235409) might be associated with susceptibility to CL infection. These data may be used for detection of sensitive individuals and prevention of CL in endemic areas. © 2016, Malaria Research Center. All rights reserved

Iron Deficiency and Acute Seizures: Results from Children Living in Rural Kenya and a Meta-Analysis

There are conflicting reports on whether iron deficiency changes susceptibility to seizures. We examined the hypothesis that iron deficiency is associated with an increased risk of acute seizures in children in a malaria endemic area