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Volume 0, Issue 0 (Articles accepted at the time of publication 2024)
Writing assessment literacy(WAL) for second or foreign language (L2) teachers, which refers to teachers’ knowledge, conceptions, and practice of writing assessment in L2 contexts, has lately received attention from scholars. Although there has been significant debate about the impact of contextual and conceptual factors on teachers’ assessment literacy, studies focusing on how such factors influence teachers’ WAL are lacking. The purpose of this qualitative study was to explore the way Iranian English writing teachers' conception of assessment, and macro, meso, and micro contextual variables impact their writing assessment practice. It also looked at how writing teachers make assessment decisions in order to negotiate and find a compromise when their assessment views and beliefs diverge from the assessment policies in their local contexts. The data was collected through semi-structured interviews with ten in-service l2 writing teachers in Iran. The findings show that participants had positive conceptions about formative writing assessments but they stated that they mostly used summative assessment in writing classes. Macro level contextual factors turned out to mostly impacted teachers’ writing assessment practices and conceptions. The results underscored the role of school and work experience in shaping and changing writing assessment conceptions. The findings of this study contribute to our current understanding of WAL development and provision of more efficient assessment training for language teachers in teacher education programs.
Volume 2, Issue 8 (Winter 2022)
The purpose of the research was to the role of influential people in sports intentions. Descriptive-correlational research method; In terms of functional purpose, it was sectional in terms of time. The statistical population consisted of all the people who followed influential people on Instagram. Sampling was available online on social networks as a sample. Instruments for measuring information variability and social interaction from Harry Doxy and Hanson (2009), validation from Ohanin (1990), interpersonal interaction from Pierce and Rubin (1988), attractiveness from Greenwood et al. (2008), entertainment from Chao (2011), The intention to watch fitness on Instagram, the intention to exercise, the attitude towards fitness and the tendency towards fitness movies by Hsu and Line (2008). Internal and external evaluation of the model was performed based on structural equation modeling. Research findings showed; the first, second, third, fourth, seventh, eighth, ninth and tenth hypotheses were confirmed. In addition, the fifth, sixth and eleventh hypotheses were rejected. The current life is inevitably influenced by the performance of new media such as Instagram, and Iranian society is no exception. Therefore, following such a process, the fitness department is creating ideas taken from this media to guide them in the direction that is accompanied by acceptance from the audience.
Volume 9, Issue 4 (Fall 2023)
Aims: Antimicrobial peptides (AMPs) are beneficial compounds that could be used as a new and effective method to suppress microbes. Both Ib-AMP4 and LL37 are antimicrobial peptides with a wide range of antimicrobial activities. This research aimed to evaluate the antibacterial potential of LL37-rIb-AMP4 hybrid protein as an antimicrobial agent against pathogenic bacteria. Therefore, its antibacterial effects against Acinetobacter baumannii, Pseudomonas aeruginosa, vancomycin-resistant Enterococcus (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) were investigated in vivo and in vitro.
Findings: LL37-rIb-AMP4 Protein with molecular weight= 28 KD was correctly produced and purified. Despite the lack of synergistic effects between LL37 and rIb-AMP4 peptides in vitro, the stability test results showed higher stability for LL37-rIb-AMP4 hybrid protein.
The findings of in vivo tests confirmed that all infected mice were improved with LL37-rIb-AMP4 and no signs of bacteria were observed in their blood and spleen samples. Also, these results confirmed the stability and higher activity of LL37-rIb-AMP4 than the single form of these proteins.
Conclusion: Considering the antimicrobial potential of the produced proteins, it seems that the recombinant LL37-rIb-AMP4 protein could be considered and used as a stable and active antimicrobial drug in future studies.
Volume 10, Issue 3 (Summer 2022)
Aim:An attempt was made to understand the influence of climate change on thefuture potential distribution of Centaurea balsamita
In the world. Centaurea balsamita is an annual plant from thesunflower family (Asteraceae) that invades fallow and slope lands worldwide. Climate change has caused extreme weather events and has had widespread impacts on the global ecosystem, including
thedistribution of plant species.The CLIMEX software is used globally for analyzing potential distributions of species.
Material and methods:The experiments were conducted in Mashhad, Khorasan Razavi Province.In the present study,CLIMEX software was used to study thepotential distribution of this plant in the world at present and future climate conditions.CLIMEX software requires five climate variables, including average, maximum, and minimum monthly temperature, precipitation and relative humidity at 9 Am and 3 Pm.These data were obtained from various sources such as "CRU TS v. 4.03" and used for the model predictions. Following the data collection, the values were adjusted and incorporated into the CLIMEX Modelling software.Using the literature data, we collected information onThe biology and ecology of Centaurea balsamita relevant for modeling the distribution of this species in Iran and worldwide underCurrent and future climatic conditions.Findings:Our results revealed that in current conditions, Europe, Asia, and North America are suitable locations for this invasive weed dispersal, and most parts of Europe have optimal conditions (20≤ EI) for dispersal of C. balsamita. It is likely that the suitable C. balsamita habitat area will be wider in some parts of the world such as Asia, America, and Europe under future climatic
Volume 12, Issue 1 (Spring & Summer 2008)
Urmia lake is located in the north-west of Iran and is recognized in the world as a largest habitat for Artemia. The last decade drought episodes and recent dam construction programs have simultaneously caused more evaporation of the lake water and thus considerable variations of water surface levels. The main aim of the present study was to map of Urmia lake water surface changes on a seasonal, periodical and over long-term scales. For this purpose, some different types of multi-scanner, spectral and temporal images (MSS, TM, ETM+, IRS-1C, MODIS and TOPEX/Jason data observing from 1976 to 2005) were processed to generate most of the thematic models in spatial and temporal contexts. First, to choose a number of referred images captured, some ground-based observation data and the obtained information from TOPEX/Jason satellites were analyzed. Then based on the available archived imageries, all the multi-date satellite data were chosen and progressively geo-referenced and then geo-rectified by ERDAS Imagine software package based on the reference ground control points. Subsequently, all the time series images were analyzed to derive some pre-defined segmented Classes such as water surface categories and shorelines changes. The revealed models demonstrated several seasonal persuaded fluctuations and considerable periodical change on the Urmia Lake coastlines particulaarly during the last decade. These great variations have occurred as the result of 3.5 meters decrease in the height of water in the lake and about 23 percent decreasing of water surface during the past 30 years. This has successively caused a diminishing of shorelines particularly on the southeast and east coasts of the Urmia Lake, changing landcover and landuse types by depletion of significant wetlands. Implementation of such significant changes illustrated that the majority of local biotic and biotic components all over the surrounding areas and inner islands, would be in crucial threat in the near future.
Volume 12, Issue 1 (April & May 2021 (Articles in Persian) 2021)
Despite growing interest in the studies on ZPD, its operation in the forms of individualized and group-wide has been controversial. To cast some empirical light on the issue, this study was designed to quantitatively and comparatively study the applicability of the two scenarios of ZPD-based instructions to the writing accuracy of Iranian EFL learners in terms of learners' types (low vs. high scorers). To this end, 118 EFL learners identified as homogeneous based on TOEFL ITP test were randomly assigned into two equal experimental groups (individualized and group-wide ZPD-based) which respectively received compatible instructions utilizing individual and whole-class scaffolding techniques. The treatments were allocated to the groups in a random manner within homogeneous blocks. Prior to and after the treatments, three tests (two writing tests and one ZPD test) were administered to measure both groups’ writing accuracy and their ZPD levels. A ZPD test was also administered in the mid of treatments. Results revealed that I-ZPD-based instruction is constructive to the low scorers, and GW-ZPD-based instruction is not constructive to both low and high scorers. The findings pointed to the use of ZPD-based instructions in TEFL writing in meaningful contexts and thereby showing impacts made on the writing accuracy of learners. The study, indeed, yield support to the feasibility of GW-ZPD measurement along with I-ZPD approach.
1. Introduction
Vygotsky’s (1978) Socio-Cultural Theory (SCT) is regarded as a major breakthrough in the field of social psychology and as a resultant in education in general and language education in particular given the significant role of sign system in social construction. SCT is based on certain macro principles mainly including developmental analysis of mental program, social basis of human cognition, scaffolding, mediated learning, and ZPD. In Vygotsky’s sense, scaffolding is defined as the “role of teachers and others in supporting the learner’s development and providing support structures to get to that next stage or level” (Raymond, 2000, p.176, as cited in Van Der Stuyf, 2002).
While SCT principles have been implemented as to certain skills of language ability, writing skill seems to have been left intact to some extent. While writing is one of the main and productive skills, as well as a significant requirement for EFL learners. It is the most difficult skill to master because of its difficulties in generating, organizing, and translating ideas into a readable text (Richards & Renandya, 2002). At the same time, writing is often considered as the most difficult skill to be mastered (Hapsari, 2011). Researchers (Ellis, 2003; Skehan 1998) are now in agreement that L2 proficiency, in general, and writing proficiency, in particular, are multi-componential in nature, and that their principal dimensions can be adequately and comprehensively captured by the notions of complexity, accuracy and fluency (CAF; Housen and Kuiken, 2009).
Writing accuracy refers to “the extent to which the language produced conforms to the target language norms” (Skehan & Foster, 1996, p. 232). Accuracy refers to the production of error-free language. It is estimated by considering the percentage of error‐free clauses (Skehan & Foster, 1996; Skehan & Foster, 1999; Yuan & Ellis, 2004) and the percentage of correct use of target features (Crookes, 1989, as cited in Ellis, 2004).
Scaffolding associates peer-and cooperative endeavor but its implementation seems unimaginable in the absence of ZPD measurement and operationalization. Analogous to society, classroom setting is the combination individuals working and cooperating in a community. It is a must and, of course, to some extent more feasible to identify and probably measure one’s ZPD in a bid to offer some kind of compatible education and input. Nevertheless, pure individualization may look at odd with the other principles of SCT, which is strongly in favor of socially-mediated learning and defining learning as movement along the continuum of intra-personal and inter-personal processes. Such a social, cooperative, and collaborative nature of learning and development requires an initiative to measure both I-ZPD along with GW-ZPD such that the expected mediation, scaffolding and inter-personal and intra-personal processes can be compatible and cooperative. Then, the main problem to be addressed is twofold: operationalization of the varieties of ZPD-based instruction (i.e. I-ZPD vs. GW-ZPD), and incorporation of these two varieties in teaching writing skills in relation to the learners’ variables such as their proficiency level in the form of e,g, test scores.
Based on the significance of the two categories of ZDP and writing in EFL contexts on one hand and the undesirable status of the writing performance of Iranian EFL learners (Hasani and Moghadam, 2012) on the other, this very study is rationalized on the following two premises:
- the interfaces between EFL learners’ writing quality in terms of accuracy and the two types of ZPD-based instructions (i.e. individualized and group-wide)
- these instructions’ effect on enhancing writing quality (i.e. accuracy) of Iranian EFL learners in terms of learners' types (i.e. low and high scorers).
In order to accomplish these objectives, the present study, focusing first and foremost on measuring each target learner’s I-ZPD and then on their GW-ZPD or average ZPD, and second on the feasibility and application of each ZPD scenarios in developing writing ability of Iranian EFL learners. More specifically, the following main question realized through four minor ones were posed:
1. Is there any significant difference in the effect of group-wide ZPD-based instruction and individualized ZPD-based instruction on the writing accuracy of Iranian EFL learners in terms of learners' types (low vs. high scorers)?
1.1 Does GW-ZPD-based instruction and I-ZPD-based instruction have different impact on the accuracy of EFL low-scored learners’ writing?
1.2 Minor Q: Does GW-ZPD-based instruction and I-ZPD-based instruction have different impact on the accuracy of EFL high-scored learners’ writing?
1.3 Minor Q: Does GW-ZPD-based instruction have significantly different effect on low scorers compared to high scorers in developing their writing accuracy?
1.4 Minor Q: Does I-ZPD-based instruction have significantly different effect on low scorers compared to high scorers in developing their writing accuracy?
2. Methodology
The research was conducted empirically through the implementation of the pretest-treatment-posttest design. A homogeneous group of 118 undergraduate, intermediate Persian EFL learners of both genders in the age range of 18 to 22 years old majored in Translation Studies from a university in Tehran students was selected based on their performance on their TOEFL ITP. Then, three pre- and post-tests (two writing tests and a ZPD test) were administered in the first and the last sessions, respectively. The two treatment groups were formed randomly to receive two types of ZPD-based instructions (individualized and group-wide). Another ZPD-test was also administered in the sixth session of the treatment in order to study ZPD development of the two treatment groups and give them their most suitable ZPD-based instructions.
Ultimately, comparison was made between the pre- and post-tests’ scores of the two intact writing classes. The learners’ ZPD development was measured before, after and in the mid of treatment using Raven’s Standard Progressive Matrices (SPM; Raven, 1998). Their ZPD development was, indeed, assessed and analyzed on a weekly basis and a monthly basis (three times in the semester -- before, after, and in the mid of treatment) taking the advantage of Kozulin and Garb’s (2002) learning potential score’s (LPS) formula.
To estimate the inter-rater reliability between the two raters, a randomly selected cluster of writing papers, including 28 sets of papers, scored by the two raters. Running Pearson correlations between these score sets indicated that there were significant agreements between the scores of writing accuracy (r (27) = .73, P < .05 representing a large effect size) as provided by the two raters. As a result, the researcher employed the mean of the two scores provided by the two raters as the final score for each participant’s writing performance in terms of their writing complexity, accuracy.
The treatment was applied for two consequent semesters in order to increase the intra-rater reliability of the findings. Running Pearson correlations between the score sets taken from the first and second semester’s participants of the study indicated that there were significant agreements between the two sets of scores of the participants’ writing performance (r (32) = .83, P < .05 representing a large effect size). As a result, the researcher employed the mean of the two sets of scores taken from the participants during the first and the second semesters as the final score for each participant’s writing performance in terms of their writing accuracy.
3. Results and Discussion
Due to the non-interval nature of the data, all research questions were probed through non-parametric analysis of covariance (ANCOVA) and Friedman’s test.
As to the first and the second minor research questions about the impact of the two types of ZPD-based instructions on the writing accuracy of the low scorers, and the high-scorers, the researchers taking advantage of the criteria proposed by Wigglesworth and Storch (2009) for the measurement of writing accuracy, came up with the following findings:
- The I-ZPD-based instruction helped the low-scored learners outperform GW-ZPD-based instruction group on the accuracy of writing (+.003 vs. -.136).
- While the I-ZPD-based instruction acted as a stronger deterrent against writing accuracy of the high-scored learners than the GW-ZPD-based instruction (-.037 vs. -.078).
As to the third and the fourth minor research questions on the effect of the GW-ZPD-based instruction, and the effect of the I-ZPD-based instruction on the writing accuracy of the low scorers compared to high scorers, the respective ANCOVA came up with the following findings:
- The GW-ZPD-based instruction act as a deterrent against writing accuracy of the low scorers (-.136) and high scorers (-.037) respectively significantly and slightly.
- And, the I-ZPD-based instruction acted slightly as a deterrent against writing accuracy of the high scorers (-.078) while acting as a very slight developer of writing accuracy of the low scorers (+.003).
As to the main question on the significant difference in the effect of the g-wide ZPD-based instruction and the I-ZPD-based instruction on the writing accuracy of Iranian EFL learners in terms of the learners' levels (i.e., low vs. high scorers), the researcher defined the I-ZPD-based instruction’s positive impacts on the writing accuracy of the low scorers, and the g-wide ZPD-based instruction’s negative impacts on the writing accuracy of the both levels of the learners (more on the low scorers than the high scorers).
4. Conclusion and Implications
In brief, two main conclusions from the above-mentioned discussion were drawn: 1) I-ZPD-based instruction is constructive to the writing accuracy of the low-scored learners. 2) GW-ZPD-based instruction is more destructive to the writing accuracy of the low scorers than the high scorers.
The results of the present study cast new light on the nature of ZPD, highlighting the significant difference between the two ways of its running (i.e. individualized vs. group-wide) and the achievements of the two types of EFL learners (i.e. low scorers vs. high scorers). These findings were in line with the results of the studies conducted by many other researchers on the individualized scaffolding technique of conference writing (e.g. Aljaafreh & Lantolf, 1994; De Guerrero & Villamil, 1996; Nassaji & Swain, 2010) and on the whole-class scaffolding technique of template studied by several other scholars (e.g. Baleghizadeh et al., 2011; and Smit et al.,2013).
This study has significant pedagogical implications. Syllabus designers can apply two types of scaffoldings (used in the two types of ZPD-based instructions; i.e. group-wide and individualized) effective for the writing accuracy of the relevant low- and high-scored EFL learners to textbooks. The merit of these two types of ZPD-based instructions is that they challenge writing accuracy of the two types of EFL learners differently but in their ZPD providing guided free exploration.
Volume 12, Issue 2 (Spring 2024)
Participants & Methods: The current study was a qualitative research employing descriptive-exploratory method and carried out in Tabriz in 2023. The used components were identified based on document review and semi-structured interview tools. In order to review the documents and analyze the interviews, three levels of open, central and selective coding were used. In order to comprehensively identify the main components and sub-components of the comprehensive performance evaluation model, in addition to reviewing the studies conducted in this field, a semi-structured interview was conducted with 15 experts in the field.
Findings: 8 main themes and 28 sub-themes were identified. Professional commitment, professional development, professional skills, research skills component, personality characteristics component, teaching and educational activities, consulting services and social-political activities were the main themes.
Conclusion: The performance evaluation of clinical academic faculty members is an effective process to identify strengths and weaknesses and is the basis for the participation of academic faculty members to improve quality in university development planning.
Volume 13, Issue 5 (November & December 2022 (Articles in English & French) 2022)
Despite the fact that interpreting has long existed in history and predates translation, the interpreter training as an autonomous discipline is non-existent at the graduate level in Iran. The paramount focus of this study was to probe into the status quo of interpreting courses in the Iranian academia and subsequently delve into the possible expediencies to establishing such a discipline in the higher education. To this end, 15 professional interpreters (9 from Iran and 6 from other countries), 10 interpreter trainers (4 from Iran and 6 from other countries) and 118 English Translation Studies students (32 M.A. and 86 B.A.) who were selected through convenience sampling participated in this study. The students filled out a 20-item researchers-designed Likert-scale interpreting status quo questionnaire and the interpreter trainers and interpreters were invited for a formal semi-structured interview. Findings, analyzed quantitatively by SPSS software version 28 and qualitatively by inductive codification process, revealed the existing situation of the interpreting courses in the Iranian academia in terms of needs analysis, objectives and syllabus, methodology, materials as well as course contents and ensured the significance of establishing interpreter training as an independent discipline in the higher education among all stakeholders, i.e. interpreters, interpreter trainers (teachers) and interpreter trainees (students) for a number of expediencies including non-existence of this discipline in Iran, the need for academization, its multidisciplinary nature, dearth of specialization, addressing stakeholders and researchability, generating pertinent activities, glocal reputation, and employability.
Volume 14, Issue 4 (12-2014)
Many variables under study in hydrology are continuous and random; hence, it necessitates using probability and statistics sciences to study them. In a specific classification, variables are categorized to be either explanatory or response variable. An explanatory variable is defined as a variable which explains or predicts changes in the value of another variable, while a response variable is a variable whose prediction of its changes is desired under the effect of other variables. Due to the mentioned definition, a response variable may depend on one or more explanatory variables. Therefore, in the first case the response variable is intrinsically univariate and in the second case is intrinsically multivariate. If it is known that a hydrological response variable is intrinsically multivariate, multivariate statistical approaches must be employed, especially in the case of dependency among explanatory variables, because it has been widely warned that implementing univariate statistical approaches may result in over/under estimations. According to the fact that flood is an intrinsically multivariate event, it is essential to employ multivariate approaches to analyze it. The most important characteristics of flood are peak discharge, volume and duration. A traditional approach in multivariate analyses is to use classical multivariate distribution functions with parametric marginal distribution functions. However, both classical multivariate distribution functions and parametric distribution functions face substantial limitations. Among the limitations attributed to classical multivariate distribution functions, one may refer to the necessity of identifying marginal distribution functions and their parameters and equality of the kind of marginal distribution functions as the most important limitations. Also in the use of parametric distribution functions for marginal variables, an assumed distribution function is used to describe the distribution of data, while perhaps the assumed distribution function does not accurately describe the real distribution of data. The aim of this article is to establish joint distributions of different combinations of flood characteristics and corresponding return periods. Hence, firstly marginal distribution functions are chosen among parametric distribution functions and non-parametric distribution functions, which are not restricted to estimation of some parameters. Then joint analyses of flood variables are performed using copulas, which do not confront limitations of classical multivariate distributions. Finally, having found and appropriate copula for each combination of flood characteristics, joint return periods are calculated and contour plot of joint return periods are plotted. Joint return periods of flood characteristics can be used by water resources decision makers and engineers as a hydraulic design criterion and provide useful information for risk analysis. In this article, joint analyses of flood variables are performed using copulas, which do not confront limitations of classical multivariate distributions, such that marginal distribution functions are chosen among parametric distribution functions and non-parametric distribution functions, which are not restricted to estimation of some parameters. It should be mentioned that the R language has been utilized as the primary tool in order to perform calculations and draw diagrams. Keywords: Flood Frequency Analysis, Joint Return Periods, Copula, Non-parametric distribution
Volume 14, Issue 6 (9-2014)
In this work, mixed convection of Cu-water nanofluid in a trapezoidal enclosure with heat source on lateral walls has been numerically investigated. Vertical walls of the enclosure are kept at constant temperatures of Th and Tc, while horizontal walls are insulated. The mixed convection flow has been generated by passing the fluid through the enclosure and natural convection has been, also, investigated by holding the left wall at a temperature higher than the right wall. In order to examine the effect of the ports position, two cases were considered. Comparison between the results indicates that the rate of heat transfer is higher when the inlet port is near the cold wall than the hot wall. The results have been presented for various volume fractions, Richardson and Reynolds numbers. It was observed that for the considered Reynolds numbers and Richardson number, at a given Reynolds number and solid volume fraction, the Nusselt number increases with increasing the Richardson number. Moreover, at a given Richardson number and solid volume fraction, increasing the Reynolds number results in an increase in the Nusselt number. For the higher Richardson and Reynolds numbers, the nanofluid has more effect on the increase of the heat transfer performance.
Volume 18, Issue 4 (winter 2018 2018)
Volume 19, Issue 4 (7-2017)
One of the dangers that constantly threatens agricultural sector is soil erosion. The purpose of this study was to investigate and categorize farmers’ views on the factors inhibiting the implementation of soil conservation practices in Koohdasht Township, Iran. The study was fulfilled by using descriptive-correlation method. A stratified random sample of 377 farmers was drawn from a population of 19531 farmers in the township, based on Krejcie and Morgan Table for determining sample size from a finite population. The research questionnaire was validated by a panel of faculty members of agricultural extension and education at Tarbiat Modares University (TMU) and found to have sufficient content and face validity. Using a pilot study, internal consistency reliability was demonstrated with satisfactory alpha coefficient (0.73). Descriptive and inferential statistics, i.e., factor analysis, were used to analyze the data. Factor analysis produced four factors: “economic-extension”, “ecological-farming”, “social-structural”, and “organizational-management” which accounted for 49% of the total variance. The factors that emerged suggest the need for some executive measures to overcome the problems inhibiting the implementation of soil conservation practices in future programs.
Volume 20, Issue 4 (April 2020)
Volume 20, Issue 11 (October 2020)
The main disadvantage of natural draft dry cooling towers is the influence of atmospheric conditions as ambient temperature and wind speed on the thermal performance. Wind disrupts the natural flow of air inside the tower creating vortices at the back and inside the tower that disrupts the air flow structure. When the wind blows, increasing the velocity of inlet air through the front louvers causes the air to pass through the behind louvers rather than outlet opening. The negative effect of this phenomenon reduces the cooling performance and consequently reduces the turbine production power in power plants. A good solution to this problem is to adjust the Louvers angle correctly. Therefore, in the present study, the thermal performance of the dry cooling tower was evaluated under the conditions of opening and closing the front louvers and changing their angle. In this regard, a natural draft dry cooling tower unit with the dimensions of the cooling tower located in combined cycle power plant was simulated in 3D using fluent software and the numerical results with the experimental data have been validated. The Realizable k-ε turbulent model is used to model the turbulent flow and the performance of the tower has been studied in three modes, including no wind, with the wind and the fully open louvers and with the wind and the semi-open louvers. According to the results, by partially removing the louvers to 60°, the heat transfer can be increased to 16% and the mass flow rate to 15%.
Volume 24, Issue 3 (March 2024)
The great attention and interest of researchers to use ammonia in combustion systems as a carbon-free fuel for gas turbines, as well as the existence of developed infrastructure for its production, show the importance of present fuel and this issue. In addition, one of the best candidates for storing renewable energies on large scales or transporting them for long distances is doubtlessly Ammonia (NH3). In gas turbines and boilers, adding landfill gas improve NH3 reactivity effectively. The present effort studies NH3/landfill mixtures’ laminar flame propagation from 1 to 10 atm in an 11-liter constant volume combustion chamber using experimental approaches such as Mach-Zehnder and Schlieren interferometry method. The numerical study was performed using the Ansys Chemkin-Pro package via San Diego, Okafor, and GRI-Mech 3.0 mechanisms which can provide very accurate predictions for laminar burning velocities. The results indicated that the most considerable influence on increasing laminar burning velocities could be attributed to Ammonia concentration in the mixture. The experiments also showed that laminar burning velocity is reduced when the pressure is increased.
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