Explaining the different efficiency behaviors of PHOLEDs with/without a hole injection barrier at the hole transport layer/emitter layer interface

In this work we investigate the different efficiency behaviors of the devices with and without hole injection barrier, utilizing in our investigation the archetypical 4,4′-bis(carbazol-9-yl)biphenyl:Tris(2-phenylpyridine)iridium(III) host–guest PHOLEDs system. The results show that the recombination of electrons and holes on the host material generally leads to higher device efficiency in comparison to the case where recombination happens on the guest material. The results also show that in devices where a hole injection barrier between the HTL and the host material in the EML exists, the emission mechanism gradually changes from one based on host e–h recombination to one based on guest e–h recombination as the guest concentration is increased. When host e–h recombination is dominant, although it tends to produce higher device efficiency, host e–h recombination is generally also associated with significant efficiency roll-off; the latter arises from quenching of the host triplet excitons primarily due to host–host TTA. As the concentration of the guest molecules increases and the creation of host triplet excitons subsides (since most e–h recombination occurs on the guest) host–host TTA decreases, hence also the efficiency roll-off. In such case, quenching is mostly caused by polarons residing on guest sites. At optimum guest concentrations (∼8% Vol.), a balance between host e–h recombination and guest e–h recombination is reached, and thus also minimal TTA and Triplet-Polaron Quenching. On the other hand, in devices where hole injection barrier between the HTL and the host in the EML is insignificant, emission mechanism is always based on host e–h recombination irrespective of the guest concentration, and therefore have higher efficiency and the efficiency does not depend on guest concentration. The absence of the injection barrier in these devices results in a wider recombination zone, and hence a lower exciton concentration in general, which in turn reduces host–host TTA and thus lowers efficiency roll-off. In contrast, guest–guest TTA is not found to play a significant role in device efficiency behavior.     

Equilibrium moisture content and heat of desorption of saffron

The equilibrium moisture contents of saffron (Crocus sativus L.) stigmas were determined experimentally using the standard gravimetric method at temperatures 30, 45 and 60 °C and water activity ranging from 11% to 83%. The sorption isotherm curves of saffron were sigmoidal in shape and decreased with increased temperature at constant relative humidity. Five selected isotherm models GAB, modified Henderson, modified Chung‐Pfost, modified Halsaey and modified Oswin were tested to fit the experimental isotherm data. Modified Oswin and modified Henderson models were found acceptable for predicting desorption moisture isotherms and fitting to the experimental data, respectively. The isosteric heats of desorption, determined from equilibrium data using the Clausius‐Clapeyron equation, were found to be a function of moisture content. The net isosteric heat of desorption of saffron varied between 1.38 and 5.38 kJ mol^?1 at moisture content varying between 2% and 20% (d.b).     

PCR amplification of 18S rRNA,single cell protein production and fatty acid evaluation of some naturally isolated microalgae

Microalgae were isolated during a screening program from soil samples collected from paddy-fields of Fars province, south of Iran. The protein content was assayed by the Kochert method. Total genomic DNA were isolated and used for PCR amplification of the 18S rRNA gene. The sequences were determined for 12 species of microalgae. Some bioinformatic tools were used for more investigation on these biologic data. Total lipids from five microalgal species were extracted and used for determination of different types of fatty acids by gas chromatography–mass spectrometry method. In our experiments the green algae yielded a maximum protein of about 42% ± 1.64. The DNA sequences were published in the NCBI under specific accession numbers. The composition of fatty acids was mainly, myristic acid, palmitic acid, oleic acid, α-linolenic acid, and γ-linolenic acid.     

Long term hygroscopic characteristics of polypropylene based hybrid composites with and without organo-modified clay

Recycled PP contains various impurities and has poor and variable mechanical properties compared to virgin PP. This, in general, rules out the use of recycled PP in the original applications and in other high-value applications. Hence, this study investigated the effects of polymer matrix type, weight fraction of wood flour and organoclay on the thickness swelling and water absorption behavior of PP based hybrid composites. WPCs based on polypropylene (virgin and recycled), wood flour, organoclay and maleated polypropylene (MAPP) were made using melt compounding and subsequent injection molding. Composites made from recycled polypropylene (rPP) exhibited better dimensional stability compared to the virgin (vPP) based ones. Besides, wood flour did not completely encapsulate in the polymer matrix at 50 % weight fraction. Incorporation of nanoclay exhibited a beneficial effect on both the water absorption and thickness swelling by creating a tortuous path as a result of its characteristic barrier property. The improvements in hygroscopic characteristics of hybrid composites using rPP and nanoclay were further supported by scanning electron microscopy and X-ray diffraction methods. Conclusively, PP recycled from post-consumer applications can be used in value-added composites without accepting the expense of separating out impurities from the polymer.     

Oil Content and Fatty Acids Composition in Brassica Species

Seeds of 20 accessions of six Brassica species including cultivated and five wild relatives were analyzed for oil and fatty acid composition. The results showed that oil content varied from 21 (B. nigra) to 46% (B. napus). Among wild species, B. rapa and B. oleracea had highest oil content (31 and 28%, respectively). The main fatty acids of oleic, linoleic, linolenic, erucic, palmitic, and stearic acids accounted for 89–94% of the total fatty acids in all species. Cultivated species of B. napus had highest oleic acid (61%) and lowest erucic acid (1%) content compared to other studied species. Brassica rapa and B. oleracea had the highest content of erucic acid (41 and 46%, respectively). The highest content of linolenic (20%) and linoleic (19%) acid was observed for B. juncea. The results showed that there was high genetic variation among the studied species for oil content and fatty acids composition. This indicates that seed oil of these species is possibly suitable for both human consumption and industrial purposes.     

Evaluation of mustard (Brassica juncea) protein isolate prepared by steam injection heating for reduction of antinutritional factors

A process for the preparation of mustard protein isolate, comprising steps such as dispersion of defatted meal in 0.1 mol/l NaCl solution, incubation, extraction at alkaline pH, followed by treatment of the protein solution with activated carbon was developed. The protein, coagulated by steam injection, was subjected to separation by centrifugation, washing and spray drying. The parameters evaluated were protein yield, purity, presence of antinutritional factors and nutritional quality of proteins. The protein yield was 58-60%. The purity of the protein isolate was 95%. The hydrolysed products of glocosinolates like isothiocyanates and oxazolidine thione levels, phenolics and phytic acid levels were low in the protein isolate. The in vitro digestibility of the protein isolate was 92.4% compared to 80.6% of the meal. Chemical score of the meal and protein isolate were similar; isoleucine was the first limiting amino acid. The calculated nutritional indices, essential amino acid index, biological value, nutritional index and C-PER of protein isolate were higher compared to meal. The protein quality as indicated by amino acid profile and PDCAAS scores for 10-12-years old and adults were 100.     

Nutritional status of rural women in relation to their participation in mixed farming in the Tafresh area of Iran

This study was conducted in the Tafresh area of Iran to assess the dietary patterns, time allocation, and nutritional status of rural women in relation to their participation in mixed farming activities. We selected 75 women from 40 villages by applying a stratified random-sampling technique. Cereals and grains were the major source of energy intake. According to the recommended dietary allowance (RDA) tables of India, the United States, the United Kingdom, and the Food and Agriculture Organization (FAO), the respondents seemed to have no micronutrient and energy deficiencies during the spring season. They spent most of their time and energy on household, animal husbandry, and crop farming activities. According to measurements of body mass index (BMI), the respondents were well nourished. However, despite the high level of BMI, analysis suggested a negative energy balance. Nevertheless, analysis indicated that rural women with negative energy balance spent more time and energy in mixed farming and had a higher level of participation in related activities. Hence, it is evident from the results that the physical contribution of rural women in mixed farming activities has a detrimental effect on their nutritional status, at least during some parts of the year (e.g., spring or summer). Therefore, there is a need to adjust nutritional interventions to improve the sustainability of their food intake and to develop appropriate technologies in mixed farming to alleviate their work burdens.     

Extraction of ferulic acid from sugar beet pulp by alkaline hydrolysis and organic solvent methods

Extraction of ferulic acid from sugar beet pulp was carried out using three extraction solvents, sodium hydroxide (0.5, 1, 2 M), methanol and their mixture (alkaline methanolic solvent). The Ferulic acid extracted by each solvent was identified and quantified by HPLC method and the effects of solvent type, concentration and reaction time on ferulic acid solubilisation were assessed. There were differences in the contents of products extracted in the experiment conditions. The minimum amount of ferulic acid was obtained from methanolic extract while the highest concentrations (957.4 mg/L ferulic acid) were obtained employing the highest NaOH concentration (2 M), and reaction time (12 h), so phenolic compounds are better released with alkaline hydrolysis than in methanol conditions. Finally a simple procedure for the purification of ferulic acid from the alkaline extracts is presented and evaluated by FT-IR spectrum.