Showing 61 results for Mohammadzadeh
Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
Climate change is one of the challenges of today to affect the agriculture sector. Climate change in Iran in recent years has caused a decrease in rainfall and an increase in temperature and continuous droughts. Agricultural production in Iran has been affected by climate change and has faced a decrease in the production of various products. The purpose of this research was to identify social, economic and environmental consequences of climate change in Iran's agricultural sector and designing a model of Planned Management Behavior (PMB). A mixed qualitative and quantitative method was used in this research. The study sample of this research in the qualitative phase included 15 key experts who have knowledge of the consequences of climate change and in the quantitative section, there were 100 experts of the agricultural Jihad of Khuzestan province. Based on the qualitative results, the consequences of climate change were identified. In the quantitative phase, it was determined that 69.3% of attitude towards the consequences of climate changes are explained by the independent variables of concerns about social, economic and environmental consequences, feeling the need for risk management, and perceived value. Also, 71.2% of changes in planned management intention to control the consequences of climate changes are affected by the attitude towards the consequences, tendency to control behavior, personal and mental norms. Finally, 69.8% of changes in PMB for control the consequences of climate changes are caused by the use of planned management intention to control the consequences, action planning and coping planning.
Volume 1, Issue 3 (Fall 2020)
Abstract
The necessity of coordinated facades especially in city centers plays an important role in the image of the cities. Setting up a reliable framework is crucial to ensure that this coordination is maintained. However, due to the lack of tools for implementing that framework the roles and regulations in this context remain only written.
The review of complied foreign documents shows that there is an intensive tool that leads to implementing façade design instructions. This tool which is called the ‘Improvement Façade Program’ has been employed in many cities across the world.
This paper aims to propound tools for implementing design instructions specified in the façade context. It is noteworthy that the main purpose of this paper is being familiar with one of the intensive tools for improving façade and applying this tool in Iran requires localization with specific conditions and regulations inside the country.
Volume 4, Issue 3 (2014 2014)
Abstract
Volume 5, Issue 1 (Winter 2019)
Abstract
Aims
Urinary tract infection (UTI) is one of the most common infections worldwide. The aim of this study was to investigate the association between ESBLs genes and quinolone resistance in Uropathogenic Escherichia coli isolated from patients with urinary tract infection .
Materials & Methods
A total of 150 E. coli isolates were collected from patients with urinary tract infection referring to Firouzgar Hospital in Tehran, Iran. Antimicrobial susceptibility of isolates were determined by disk diffusion method. Double-disk diffusion test was performed for phenotypic identification of extended-spectrum β-lactamase- (ESBL) producing isolates. PCR was used for the detection of ESBL-encoding genes in addition to quinolone (qnr) resistance genes.
Findings
There was a high resistance rate to most of the studied antimicrobial agents. Phenotypically, 75% of the isolates produced an ESBL enzyme and were resistant to different antimicrobial classes. In overall, 83% of the isolates carried ESBL genes, especially blaTEM and blaCTX-M . 75% were positive for the quinolone resistance genes including qnrA , qnrB ,qnrS and qepA. These results indicate the association between the presence of various ESBLs genes and quinolone resistance in uropathogenic E. coli.
Conclusion
Resistance patterns show the increased incidence of antibacterial resistance in E. coli. Results of the current study indicate the high prevalence of ESBL-producing isolates and quinolone resistance genes. Simultaneous presence of genes responsible for antibacterial resistance has made the treatment of UTI more challenging than ever before.
Volume 6, Issue 2 (9-2017)
Abstract
For quality assessment of coated fish fillet with sodium alginate containing inulin, fish fillet were coated with sodium alginate containing 10, 20, 30 and 40 percent inulin using two methods, including dipping and vacuum impregnation. Then fructan were determinate in coated samples. The samples including 20 and 40% inulin in vacuum impregnation and dipping respectively were selected for further study based on their higher fructan content. Therefore, the chemical and microbial changes of selected samples were investigated during 16 days, with 4 days interval in refrigerated condition (40C). Results showed that the fructan content had not changed significantly (p≥0/05) during the storage period. Peroxide in the middle of storage period was increased and then decreased significantly (p≥0/05) by the end of storage time. Quality indexes such as pH, thiobarbitoric acid (TBA), total volatile basic nitrogen (TVB-N), total plate count bacteria, psychotropic bacteria and peroxide increased significantly (p≥0/05) along time. In all of the samples, TBA at the end of 12 day storage, TVB-N at the end of 16 day storage, anaerobic bacteria count and pseudomonas bacteria count at the end of 12 day storage were more than acceptable limit of fresh fish. In the conclusion, fructan of coated fish fillet had not changed significantly during refrigerated storage, as well as shelf life of coated fish fillet by dipping and vacuum impregnation in refrigerated condition storage (40C) was less than 12 days.
Volume 7, Issue 1 (5-2015)
Abstract
This paper intends to identify Seyyed Hassan Taqizadeh's thought and its social and mental bases, and analyze his political action as an Intellectual and political actor in the era of constitutionalism according to the historical sociology approach with regard to the sociology of knowledge. Mannheim's sociology of knowledge focuses on some traits such as social position, dependence of thought to social background, and historicality of thought, and to some extend pays attention to person subjective. These are competent elements, which were used for recognizing Taqizadeh's thought and the process of becoming an active political actor. Besides, this paper uses the concept of action in its details to understand the type of Taqizadeh's action and its relation to his social and intellectual bases. According to these facts, the paper tries to answer how and to some extend why such relation exists between Taqizadeh's thought and his political action. It concludes that Taqizadeh's family position, social rank, social environment, and experiential and humanity sciences, especially evolutionism, as well as his former knowledge of Islam are the main bases of his modernity. With regard to these foundations, it should not be wondered that Taqizadeh's thought and political action are mixture of Islam, liberalism and socialism.
Volume 7, Issue 3 (10-2016)
Abstract
With regard to cultural studies approach and quality method, This research tries to represents the educational system ideas from Era of constitutionalism until Political Open Space in 1320s in order to perceive it in spite of its democratic nature of social changes, and also focuses on how authoritarian ideology were represented in educational system.
Besides, according to constitutional revolution, forming of quasi-modern and national movement, have democratic ideas been instructed or not?
This research by study of educational system as an important Ideological system in reproduction of power shows that during this period, content and the way of teaching of educational system were adapted with authoritarian discourse that was ruled between dualisms of school / family relation and sensitive subject of school was under inspiration and dictating of some mechanisms such as: authoritarianism, assimilation, dualism, conservatism, fatalism, tenderness, virtue, weaken of self- confidence and patience. Meanwhile there wasn't seemed to be any different and conflict discourse encounter with authoritarian discourse during this period.
Volume 8, Issue 2 (Spring 2020)
Abstract
Aims: The present study is aimed to determine the role of acceptance and mindfulness therapy on physical activity increment and obesity decrement in the patients suffering from heart disease in Bandar Abbas.
Participants & Methods: In terms of type, the study is applied one and in terms of research method, it is a quasi-experimental study along with a pre-test-post-test with a control group. The statistical population of the study involves all the patients suffering from heart disease being overweight who had visited Bandar Abbas’ hospitals during 2018-2019 and according to angiographic reports, eclipse was more than 50% and BMI≥30. In the present study, an available sampling method was used. The population size was 20 that 10 were assigned to experimental group and 10 to control group. The data were collected through making use of physical activity level, body mass index (BMI) questionnaire. Data were analyzed using covariance analysis and SPSS software.
Findings: Acceptance therapy had been effective on physical activity increment and body mass decrement of the patients suffering from heart disease.
Conclusion: Mindfulness-based therapy can be considered as a non-invasive treatment. This clinical trial will result in more effective mindfulness-based interventions as a complementary treatment in primary care for people with overweight and obesity.
Ahmad Jafari Samimi, Safar Farhang, Mehdi Rostamzadeh, Mehdi Mohammadzadeh,
Volume 9, Issue 4 (3-2010)
Abstract
Economic liberalization policy has been among the major concern of the governments during the last few decades. However, its impact on economic growth is still a controversial issue. The aim of this paper is to examine the impact of trade liberalization and financial development on economic growth in Iran using annual observations over the period 1973-2007. The current study would use ARDL technique to estimate the empirical model.
The findings of this paper indicate that there is a long run positive and significant relationship between trade liberalization and financial development and economic growth in Iran over the period of the study. The error correction coefficient is around 0.32 showing that the adjustment towards the long run equilibrium takes place within almost three years. The Granger causality test indicates that causality runs from trade liberalization and financial development to GDP.
Volume 9, Issue 4 (8-2020)
Abstract
Mediterranean flour moth, Ephestia kuehniella Zeller, is important for mass rearing of parasitoid insects such as Bracon wasps and it's feeding on cereals leads to economic losses in flour mills. In current research, the effects of four different diets: wheat, barley, oat, and maize flours, on protein content of larval and pupal whole-body, gut and fat bodies of the last instars and the digestive α-amylase activity were evaluated. In addition, their protein patterns were compared using polyacrylamide gel electrophoresis (SDS-PAGE). The protein contents of fifth instars whole-body, fat bodies, gut, and also pupa varied in different diets. On the whole, the lowest protein levels were found in all experiments in oat and the highest in barley and wheat. Other biological parameters such as insect weight and digestive α-amylase activity were also significantly affected by the decrease in protein content. The results obtained from the estimation of protein content by a colorimetric method and SDS-PAGE were consistent with each other; the low or high protein contents were also clearly visible in the gels. According to the results of enzyme activity and protein contents of insects reared on different diets, barley and wheat are reported to be appropriate diets for this pest, while oat and maize are not suitable diets.
Volume 10, Issue 1 (1-2021)
Abstract
To Aims salt reduction and investigation, the effect of sodium chloride (NaCl) replacement by potassium chloride (KCl) on the nutrition quality and sensory assessment of fish sauce from Common Kilka (Clupeonella cultriventris) with substituting NaCl by KCl at 0%, 25%, and 50% concentration was produced during 45 days of fermentation at 37±2 Co. The proximate composition, free amino acid profile, profile, groups, and rate of the total amino acid (TAA), indices including acid amine score, chemical score, essential amino acid (EAA) index, biological value (BV) and protein efficiency rate (PER) as well as sensory assessment, was investigated. The increase of KCl concentration led to a decrease in the sum of essential free amino acids. The most abundant amino acid in the level of 100% NaCl and 25% KCl was glutamic acid as well in the level of 50% KCl was Lysine. The highest sum of EAA and rate of EAA to TAA respectively in the level of 25 and 50% KCl recorded. Phenylalanine, Methionine, and Threonine were identified as limiting amino acids in produced fish sauces. Fish sauce with 25% KCl concentration contained a higher amount of EAA index, BV, and PER than other samples. According to sensory assessment, levels of 100% NaCl and 24% KCl were accepted by the panelists. In Conclusion, due to partly improvement in nutrition quality as well as acceptable sensory, would suggest that NaCl replaces by KCl in 25% concentration in the production of common Kilka fish sauce.
Volume 10, Issue 2 (Spatial Issue on Persian Gulf 2021)
Abstract
Fish are among the organisms that have the ability to bioaccumulate these metals. The aim of this study was to investigate the concentrations of aluminum, vanadium, tin and chromium in the muscle tissue of tapeworm and assess its potential risk. For this purpose, 30 pieces of fish were caught in July 2017 from Bushehr port, Persian Gulf. Samples were prepared according to standard laboratory methods and the concentration of heavy metals was measured using ICP-OES. The concentration of elements in the muscle tissue of fish for human consumption was compared with international standards, as well as the estimated daily, weekly absorption in children and adults, their permissible consumption and risk indicators of consumption of this fish against carcinogenic diseases. The results showed that the mean concentrations of aluminum (23.9 ±10.3), vanadium (0.15 ±0.07), tin (5.41 ±2.2) and chromium (0.34 ±0.12), based on micrograms per gram, fresh weight was observed in muscle tissue. The absorption of the studied metals in the muscle tissue of fish was Al> Sn> Cr> V. The results showed that the permissible consumption of heavy metals with the exception of aluminum was lower than the standard of the World Health Organization. The calculation of the risk index showed that aluminum in both groups of adults and children and chromium in children have values of more than one, in this regard, with continuous monitoring of heavy metal surfaces in fish offered in the market
Volume 10, Issue 4 (11-2021)
Abstract
This study aimed to produce and characterize solid lipid nanoparticles containing the essential oil (SLN-EO) of Ziziphora clinopodioides Lam. The preparation was carried out using the high shear homogenization and ultrasound method. The biological activities of the prepared nanoformulation were evaluated against Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) larvae under laboratory conditions. The particle size of SLN-EO was estimated to be under 150 nm (polydispersity index, PDI < 0.2) and zeta potential was negative. Morphology of nanoparticles was in globular form as demonstrated by transmission electron microscopy analysis. The loaded essential oil (EO) in SLN was calculated as 92% using the filtration-centrifugation method. The fumigant toxicity of EO as SLN formulation against E. kuehniella larvae was three times greater than that of pure EO. Similar results, but to a lesser extent, were obtained from comparing their contact toxicities. The fumigant durability of EO was enhanced by nanoformulation for up to two weeks. The nutritional indices of larvae, including relative growth rate (RGR), relative consumption rate (RCR), and feeding deterrence (FDI), were influenced considerably by SLN-EO compared to pure EO. The findings suggested the solid lipid nanoparticles as a suitable nanocarrier for EO in sustainable control management of Mediterranean flour moth.
Volume 10, Issue 4 (12-2021)
Abstract
To aim health risk assessment and determination of consumption rate limit of King soldier bream (Argyrops spinifer), Pickhandle Barracuda (Sphyraena jello), and Japanese threadfin bream (Nemipteru japonicus), 33 fish specimen was harvest from Jofre fishing area. After transport fish to the laboratory, was prepared and concentration of heavy metal iron, manganese, and cobalt was measured by Inductively coupled plasma - optical emission spectrometry, (ICP-OES). The Concentration of heavy metal in the muscle of fish compared with international standards. For health risk assessment Target Hazard Quotients (THQ) and Total Target Hazard Quotients (TTHQ), for determination of consumption rate limit estimated daily intake (EDI) and estimated weekly intake (EWI), Consumption Rate Limit (CRlim) and Consumption Rate Limit meal month (CRmm) in two groups include adults and children were calculated. The Results showed that manganese content in all three fish species (36.59 to 55.48 µgr/gr) more than the world health organization (WHO) and the United States Environmental Protection Agency (USEPA). Also Cobalt content in Argyrops spinifer and Sphyraena jello (66.62 and 0.38 µgr/gr) more than WHO. According to THQ, TTHQ, EDI, and EWI, the Consumption of none of the three fish species had not health risk for the consumer. Additional to the highest CRlim in adults and children determinate as in Argyrops spinifer and Sphyraena jello was manganese, respectively (10.12 and 2.17 µgr/gr), (29.36 and 6.29 µgr/gr) and in Nemipteru japonicus (184.25 and 39.48 µgr/gr) Cobalt determinate.
Volume 11, Issue 0 (پاییز و زمستان 87- 2009)
Abstract
Objective: Herpes simplex virus (HSVs) is a widespread human infectious agent, responsible for persistent and latent infections. Herpes simplex virus infections are usually continually recurrent in the normal population and represent a significant cause of complications in immunocompromised patients.
Materials and Methods: In this study HSVs were propagated in BK cells and more than 502 samples were taken and analyzed for HSV IgG antibodies using Virus Neutralization Test (VNT) as golden standard test for evaluating in house Enzyme Linked Immunosorbent Assay (ELISA).
Results: Based on the results 80.48 % and 81.67% were positive (1.8) in VNT and ELISA respectively. There was a significant correlation between the VNT and ELISA tests in the tested samples (Pearson’s r = 0.96).
Conclusions: Our data showed that the in house ELISA can be used for screening and determination of the prevalence of HSV IgG antibodies, which can facilitates patient management using suitable and cost effective laboratory diagnostic tests.
Volume 11, Issue 3 (Vol. 11, No. 3 (Tome 57) (Articles in Persian) 2020)
Abstract
Routine verbal communication almost never occurs in quiet. Speech perception disorder in noise is one of the most common complaints of people of all ages. In our living environment, there are different types of background noise that have different masking effects. In general, verbal noises have more signal target masking. Babble noise as an interfering factor can lead to speech perception disorders. Speech phonemes are alienated into consonants and vowels across languages. These phonemes are different in terms of production and perceptual mechanism. Persian has 6 vowels /i/, /e/, /a/, /â/, /o/, and /u/. Vowels are the nucleus of the syllables and words, vowel errors can lead to disorders in speech perception process. Now the question arises as to whether the ability of vowel recognition in the presence of babble noise is influenced by age, signal to noise ratio, gender, and educational level? Also, if the above factors affect the recognition of the Persian vowel, which vowels are more vulnerable to these effects?
Therefore, due to the absence of similar studies on the effect of the aforementioned factors on the recognition of Persian vowels, the present study examined the effect of age, signal to noise ratio, sex, and educational level on the recognition of Persian vowel in the fourth and fifth decades of life. This observational and cross sectional study was performed on 60 adults with normal hearing in the age range of 30-49 years with mean and standard deviation (SD) of 38.88±6.23 years old (thirty people aged 30 to 39 years old with average age and standard deviation (SD) of 33.40±2.35 years and thirty aged 40 to 49 years with average age and standard deviation (SD) of 44.73±2.33 years) from available samples. After the auditory and speech evaluation, the recognition of Persian vowels were examined in consonant-vowel-consonant syllable in the presence of babble noise in signal-to-noise ratios of 0, -5 and -10, along with the randomized presentation of stimuli to the right ear. The purpose of the random presentation of syllables in the present study was to avoid memorizing words.Comparison the recognition score of six Persian vowels showed significant differences in three signal-to-noise ratios (p = 0.001). Also, comparison the vowels recognition scores were significant in two age ranges of 30-39 and 40-49 years old in three signal-to-noise ratios (p = 0.001). However, not found significant differences between the sexes (P= 0.991) and different educational levels (P= 0.282). Also, in three signal to noise ratios of 0, -5 and -10, the recognition scores of the front vowels were better than the back vowels. In signal-to-noise ratios of 0 and -5, the highest mean of recognition score was associated with / a / vowel and in the signal-to-noise ratio of -10 with / i / was present. Also, there was the lowest mean of recognition score in signal-to-noise ratios 0, -5 and -10 with / u / vowel. The present study showed that the average recognition of Persian vowels is affected by age, signal-to-noise ratio, and type of vowel. As the age increases and the signal-to-noise ratio decreases, the average recognition score of the vowels decreases significantly in the presence of babble noise
Yousef Mohammadzadeh, Davood Daneshjafari, Seyyed Yaser Majidi,
Volume 11, Issue 4 (1-2012)
Abstract
Empirical studies imply that natural resource abundance plays an important role on economic growth in natural-resource-rich countries. The growth literature shows that human capital, education, technology progress and institutional quality are effective factors on economic growth. This article using a panel data firstly investigates the Resource Curse Hypothesis and then analyzes the effective factors and how they affect RCH. Among several effective factors that are reported in present studies, in this paper the main focus is on Human Capital and Institutional Quality. The sample for this research is two groups of petroleum exporting countries: A) Major petroleum exporters and B) Other petroleum exporters which are analyzed for the period 1996-2006. Results show that Resource Curse is seen in major Petroleum Exporting Countries. The findings also confirm the importance of low institutional quality and inadequate investments in human capital in case of resource curse. The results confirm that natural resource abundance has a negative impact on growth if considered in isolation, but a positive direct impact on growth if other explanatory variables, such as human capital, institutional quality, openness and etc. are taken into account.
Volume 12, Issue 4 (10-2010)
Abstract
Objective: Today, AIDS is considered as a global problem and many efforts to generate an effective vaccine against this disease have been made, but remain inconclusive. DNA vaccines are a member of the new generation of vaccines that can efficiently stimulate the immune system. However, recent findings indicate low immunogenicity for these vaccines and it is believed that these types of vaccines require strategies that could infer more immunogenicity. The employment of adjuvants could be considered as one of the most important methods involved. In this study, a DNA vaccine candidate for HIV P24-Nef is constructed and then using genetic adjuvants IL-15 and GM-CSF, cellular immune responses have been studied.
Materials and Methods: In this study the gene structure of HIV P24-Nef in eukaryotic expression vector was constructed and expression vectors of IL-15 and GM-CSF were used as adjuvants. After inoculation of the candidate vaccine to BALB/c mice, cytokine patterns, lymphocytes proliferation and cytotoxicity were analyzed.
Results: Our findings indicate that candidate vaccine significantly stimulated cellular immune responses. The usage of IL-15 and GM-CSF as DNA adjuvants together and separately with candidate vaccine has strengthened cellular immune responses significantly. Co-administration of DNA adjuvants significantly increased cellular immune responses when the ratio of the vaccine dose was more than the adjuvants.
Conclusion: The sequences that we selected as candidate vaccine demonstrated good immunogenicity in mouse model and co-administration of IL-15 and GM-CSF DNA adjuvants increased cellular immune response to DNA vaccine construct.
Volume 12, Issue 4 (October & November 2021 2021)
Abstract
Considering the analysis of phenomenological discourse from the semiotic perspective, the tattoo semiotic system focuses on linguistic reproduction. Discourse reveals some aspects of sensory perception to the subject. Proper body is a path to the sensory perception of the lost dimensions of meaning and the lived experience of phenomena. The purpose of this study is to investigate the process of sensory perception of phenomenological tattoo in the framework of semiotics of discourse. Throughout the research process and with the development of Merleau-Ponty and Landowski theory, the authors study the written tattoo with the semiotic approach of Paris school of semiotics by dealing with the process of discovering, producing and receiving meaning. In the present study, the findings showed that the phenomenological tattoo leads the semiotic system of language towards the discovery of the lived experience of presence and reveals the hidden layers of meaning and conceal the obvious meanings. This is a feature of meta-discourse that manifests itself within discourse in order to achieve power and immortality, and leads to transcendence of semiotic system of discourse.
1. Introduction
Linguistic signs that are purposefully imprinted on the body by painting, tattooing or bruising are considered to be tattoo in this article. What is clear is that the tattoos are painted on human bodies for ideological, cultural, social, epic, mystical, ritual and aesthetic functions. The presence of Tattoos in Iranian folk culture with various functions indicates its importance in the manifestation of the language system. The subject, in an Ethos relationship due to the presence of the tattoo object, mutates beyond an aesthetic discourse into meta-discourse and seeks a direct interaction with the existence of presence. Merleau-Ponty believes that the world contains meanings in relation to the body-subject. According to him, sensory perception is a kind of absorption and fascination in the world. The actant subjects are separated from the system of continuity in the spark of the moment, and thus meaning is reproduced and perceived at the level of discourse deep structure. The subject faces a fundamental challenge and problem within himself for essence and the way of survival and to express power in life; and by imprinting a mental idea on his body, it crystallizes the flow of linguistic fluid, the result of which is the metamorphosis of the stative subject from within.
2. Literature Review
The main issue of this research is to read the semantic system of a corps propre beyond a definite linguistic text as a phenomenal text, based on the study of semiotigue with a phenomenological perspective. The main question in this research refers to the way of the subject's sensory perception in the interactive process of the subject and the tattoo object, and examines the phenomenal text based on Landowski's discursive semantic systems. The discourse analysis of the semantic system in this study is based on the sensory perceptual principle. The theoretical foundations of this interdisciplinary research are the combination of Merleau-Ponty phenomenology with the semiotigue of the Paris school. The study of the corpus in this research is descriptive-analytical and the method of data analysis is qualitative. The present study is grounded on the Landowski's accident and adjustment discourses based on the sensory perceptual principle.
3. Methodology
Semiotigue is a discourse-oriented approach that concentrates on the process of producing, receiving and perceiving meaning and reads it in a dynamic and fluid communication of enunciation. In soft semiotigue, which was initially formed from the idea of Greimas's imperfection of signification, subjects attempt to create language with a poststructuralist view in order to achieve imperfection of signification, and avoid repeating definite linguistic implications. In reading Eastern literary and visual texts with soft semiotigue, one can reflect on the process of discovering and intuition of subjects within the narrative; and with the passage of linear time at language deep structure in a pure and attractive form due to the moment of spark, one can perceive deep abstract concepts derived from religion that are beyond the reach of subjects at the level of semantic surface structure.
4.Conclusion
In the analysis of tattoos from the perspective of Landowski's semantic systems, we have reached the approach that the semantic function of tattoos is not always definite and due to the occurrence of meaning, there is a possibility of the presence of a corps propre. Phenomenological tattoo leads the semantic system of language towards the discovery of the lived experience of presence.
The discourse of rebellion transforms the actant subject into an anti-actant one, and in adaptive interaction with the pseudo-subject imprinted on his body, intensifies the risk of discourse. Discourse transforms the rebellion of the active subject into a subconscious and, in adaptive interaction with the pseudo-subject imprinted on itself, intensifies the risk of discourse. In these works, the phenomenal text reveals the underlying and hidden layers of meaning and conceals the obvious and definite meanings. This is a prominent feature of meta-discourse that manifests itself within discourse in order to achieve the value of power, becoming a hero, and survival, and transcend the semantic system of discourse. This phenomenal space is no longer definite, argumentative, and cognitive, and brings the subject into an existential discourse.
Volume 12, Issue 6 (3-2013)
Abstract
In this study, the effect of number of stages on Tesla microvalve performance has been studied. To do this, different layouts including one to four-stage microvalves are investigated numerically. The main criterion is used for evaluation of valves performance is diodicity. Two-dimensional and steady state computations of the fluid flow have been utilized that reveal a strong dependence of diodicity on Reynolds number and the pressure drop. The results showed that for the same flow condition, the diodicity average of the two-stage microvalve is approximately 1.32 times of that of one-stage. Additional stages increase the complexity and they do not change the diodicity considerably. It is concluded that two-stage layout of Tesla type valve is the best option between the studied layouts. A two-stage layout of this valve in valveless micropump besides being compact, has the adaptability of the various functions. Also, the two-stage valve performance in three different sizes is compared with nozzle - diffuser type valve. Comparisons which are performed based on calculation of diodicity for applicable range of Reynolds numbers show that the diodicity is function of Reynolds number and is independent of the valve size. Also, the superiority of the Tesla type valve for higher Reynolds number and its weakness at lower Reynolds number are shown.