133 research outputs found
Optimization of ultrasound-assisted extraction of ascorbic acid from fennel (Foeniculum vulgare) seeds and evaluation its extracts in free radical scavenging
The main objective of this study was to compare ultrasound assisted extraction with soxhlet extraction method as control in the extraction ascorbic acid of fennel seeds. Treatment conditions were performed using soxhlet method (240 min at 85 °C) and ultrasound treatment (20 kHz, 39, 64 and 96 W/cm2, 40 and 60 °C), for 15, 30 and 45 min. No significant differences were observed for total soluble solids among the samples studied. A similar trend was observed for both the amount of ascorbic acid extract and its ability to DPPH free radical scavenging. The greatest amount of ascorbic acid obtained in 15 minutes sonication (96 W/cm2 at 60 °C), with equivalent of 1.73 mg/ml fennel seeds extraction. There was a significant difference between soxhlet and ultrasound method, which caused an increase of 69.94 mg/ml ascorbic acid in the extraction compared to the soxhlet. The highest percentage of hydrogen peroxide scavenging was observed in 15 min sonication (96 W/cm2 at 60 °C) equivalent to 74.13% without any significant difference with soxhlet method (6.93% increase in free radical). The highest percentage of DPPH free radical scavenging was observed in 15 min sonication (96 W/cm2 at 60 °C) equivalent to 98.88% without any significant difference with soxhlet method (0.18% increase in free radical). The results of the present study demonstrate that ultrasound assisted extraction is an alternative affordable for yield extraction compared to soxhlet method
A Model to Determine the Contractorsâ Claims of Construction projects
Complexity, dynamicity and uniqueness of construction projects, in addition to high financial turnover and numerous human resources increase the possibility and potential of claim between involved parties of execution. So claim is common involved and possible matter of subject. As the financial, qualitative and time effects of claims are high, it is necessary to recognize the contractorsâ claim accurately in order to take an appropriate decision. In this study, a new model is presented to recognize the contractorsâ claim which included three parts: common frequent claims, causes, and origins. To codify and design the model, 140 common claims and 60 causes which are originated of 7 origins were recognized. The model is used as decisive, determining, and anticipating model
A Model to Determine the Contractorsâ Claims of Construction projects
Complexity, dynamicity and uniqueness of construction projects, in addition to high financial turnover and numerous human resources increase the possibility and potential of claim between involved parties of execution. So claim is common involved and possible matter of subject. As the financial, qualitative and time effects of claims are high, it is necessary to recognize the contractorsâ claim accurately in order to take an appropriate decision. In this study, a new model is presented to recognize the contractorsâ claim which included three parts: common frequent claims, causes, and origins. To codify and design the model, 140 common claims and 60 causes which are originated of 7 origins were recognized. The model is used as decisive, determining, and anticipating model
Prediction of polyester/cotton blended rotor-spun yarns hairiness based on the machine parameters
Effect of rotor type, rotor diameter, doffing-tube nozzle, and torque-stop on polyester/cotton rotor-spun yarn hairiness have been studied. To model the hairiness of polyester/cotton blended yarn, artificial neural networks and regression models have been used. The results show that there are significant differences in performance of network with different architectures and training algorithms. The network with two hidden layers has the best performance and can predict hairiness with high accuracy. Relative importance of input variables is studied with partial derivatives method based on the optimum network. The results indicate that rotor type and rotor diameter have the greatest and least effect on the blended yarn hairiness
Design and Optimization of Heat Integrated Distillation
Process integration is currently considered as the main trend to improve process performance, and is one of the major approaches to reduce the annual operating and capital costs in the plant. For distillation systems, heat integration technique provides such an approach to improve the traditional simple column sequences. This work presents the optimization of distillation column sequences based on creation of maximum possible heat integration and minimizing the total annual cost of process. All the optimum simple sequences and possible heat integrated sequences are designed and considered to find the best heat integrated sequence with the minimum total annual cost. Sequences are simulated and the objective function is modeled. Basic operation parameters of sequences are changed according to the process constraints to find all the possible heat integration and minimize the objective function. The best structures with the minimum total annual cost are designed and compared for the considered industrial case study. Results show the height percent of optimization of process costs by the internal heat recovery of integration.Key words: Distillation; Sequence; Modeling; Integration; Optimizatio
Soil Erosion Control in Drylands
This book focuses on drylands such as arid, semi-arid and dry sub-humid areas where they form the main part of ecosystems, e.g., in Iran, but also around the world. Mismanagement and improper exploitation of these areas lead to more degradation day by day.
Besides an introduction to the role and importance of vegetation cover in conserving soil against wind and water erosion, this book gives a scope of appropriate techniques and methods for vegetation establishment and maintenance, indicators for suitable plants selection for soil conservation, and soil erosion prevention and combat. It provides methods of soil erosion prevention and combating through the application of plants, using bioengineering systems for soil erosion control and the role of agroforestry in soil erosion prevention.
This book can be helpful to those with an interest in countries with similar climates to Iran. In particular, this includes Dubai, Kuwait, Saudi Arabia, Afghanistan, and Pakistan
Evaluating the Effectiveness of Explicit and Implicit Form-Focused Instruction on Explicit and Implicit Knowledge of EFL Learners
Although explicit and implicit knowledge of language learners are essential to theoretical and pedagogical debates in second language acquisition (SLA), little research has addressed the effects of instructional interventions on the two knowledge types (R. Ellis, 2005).This study examined the relative effectiveness of explicit and implicit types of form-focused instruction (FFI) on the acquisition of four morphosyntactic features by four measures of explicit and implicit language knowledge. The measures included: oral elicited imitation, timed and untimed grammaticality judgment, and metalinguistic knowledge tests. A pretest and two posttests were conducted immediately and three weeks after the instructional interventions. Durable effects of FFI on low intermediate Iranian learners were found for the target language forms.In particular, explicit and implicit FFI positively facilitated the development of explicit and implicit knowledge of the target features, both immediately after the instructional interventions and, marginally decreasing, over time. Also, explicit FFI was more effective than implicit FFI as measured by both explicit and implicit knowledge tests. The findings may contribute to understanding of the efficacy of explicit and implicit FFI on L2 learnersâ controlled (explicit) and spontaneous (implicit) use of morphosyntactic forms at relatively early stages of L2 acquisition
Sr Isotopic Ratios of two Magmatic Series Unraveling the Role of Crustal Contamination in NW Firoozeh, NE Iran
AbstractTertiary basalts of NW Firoozeh in northeastern Iran are alkaline and evolve gradually towards the subalkaline andesites and dacites. Unvariant Sr isotopic ratios in the basalts, andesites and dacites indicate that the evolution of their parental melt towards progressively more differentiated melt occurred in the absence of crustal contamination. On the contrary, progressively higher Sr isotopic ratios in the alkaline basaltic trachyandesites to trachytes from NW Firoozeh suggest that crustal contamination played a significant role in the evolution of the alkaline rocks
Exploring sustainable alternatives: Wood distillate alleviates the impact of bioplastic in basil plants
The growing interest in bioplastics and bio-based crop management products in agriculture is driven by the Sustainable Development Goals of the 2030 Agenda. However, recent research has raised concerns about the sustainability of bioplastics due to their potential negative impact on crop growth and yield, with implications for the environment and human health. In this study, wood distillate (WD) was evaluated as a natural enhancer of plant growth and defence system to mitigate the negative impact of a starch-based bioplastic on basil (Ocimum basilicum L.) plants. The study analyzed physiological and biochemical changes in basil plants subjected for 35 days to single or combined treatments of WD and bioplastic by measuring biomarkers of healthy growth, such as soluble proteins, sugars, vitamin C, and malondialdehyde (MDA). The results showed that WD promoted basil development, whereas the presence of bioplastic hindered it. Interestingly, WD did not affect sugars but increased vitamin C by 12 %, which is considered a positive effect as changes in sugar levels could indicate plant stress. In contrast, bioplastic resulted in reduced sugars (â41 %) and increased (+17 %) MDA level, while vitamin C content remained unchanged. However, when WD was added to plants grown with bioplastic, it elevated the levels of all examined parameters, except for sugars and vitamin C, which experienced reductions (â66 % and 33 %, respectively). Intriguingly, despite this reduction, the observed direct correlation between sugar and vitamin C contents was maintained, indicating that the decrease in sugar content may have reached a critical threshold. This study suggests that the use of WD has the potential to alleviate the adverse effects of bioplastic on basil growth and development and highlights the importance of adopting sustainable practices in agriculture, as well as the need for a critical assessment of the environmental impact of new technologies and products
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