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Showing 214 results for Rice


Volume 0, Issue 0 (1-2024)
Abstract

Salt stress is a serious environmental threat reducing crop yield. Hence, developing any breeding plan requires an understanding of the basic physiology and cell molecular genetic regulation under salinity stress. In this study, we evaluated the effectiveness of gene expression changes on ion homeostasis comprising salt overly sensitive (SOS1) and vacuolar Na+/H+ antiporter (NHX1) along with ion content measurement and proline content in the rice mutants at Rice Research Institute of Iran in 2018-2019. To survey these realities, tolerant mutant genotypes (em4hs290 and em4hs84) along with Hashemi parent cultivar, IR28 (sensitive), and FL478 (tolerant) seedlings were treated with 100 mM NaCl. Based on the results of growth indices, the seedling length of Hashemi cultivar and IR28 decreased considerably about 44.7%, and 44.2% reduction to that of the control, and the leaves progressively yellowed. Results showed that proline content and K+ and K+/Na+ ratio increased about ~2–3-fold higher in the tolerant genotypes than in the susceptible ones. Also, the overall amount of the OsNHX1 and SOS1 expression increased in tolerant genotypes compared to the susceptible ones. Accordingly, the compatible solute accumulation significantly advanced resulting in improvement of ionic homeostasis and probably suppresses the stress. Moreover, the variable pattern of gene expression in the two salt-tolerant mutants (em4hs290 and em4hs84) and Hashemi parent showed that the induced mutation could increase the salt-tolerant in mutant genotypes through ionic and osmotic homeostasis. Generally, these tolerant mutant genotypes could be applied to develop salt-tolerant varieties in rice breeding programs which can bring on production sustainability.

 

Volume 0, Issue 0 (1-2024)
Abstract

Oil is one of the significant factors in promoting economic activities. Oil provides a considerable part of the government's revenue sources. The price of oil has always been fluctuating over the years for various reasons including political, social, and economic developments in countries. Since the price of oil affects different sectors of economy including the agricultural sector through the government budget and the revenue sources of the government, this study investigated the effect of positive and negative fluctuations in OPEC oil prices on the value added of the agricultural sector during 1990-2019. The new GAS method was used for estimating the OPEC oil price fluctuations and the NARDL method was used for estimating the long-term relationships between positive and negative OPEC oil price fluctuations on the value added of the agricultural sector. In addition to OPEC oil price fluctuations, other independent variables such as the consumer price index, employment in the agricultural sector, and the degree of trade openness were examined in the model. Based on the obtained results, the positive and negative fluctuations of OPEC oil prices in the long term had a negative effect on the value added of the agricultural sector. Furthermore, the degree of trade openness had a positive effect on the value added of the agricultural sector in a long term. results indicate that oil income is one of the most important issues that decline value added of agriculture sector and government should control this negative relation to develop agriculture as a vital sector of economic.

Volume 0, Issue 0 (1-2024)
Abstract

This study investigates the factors affecting coffee exports in Cameroon. For this purpose, we employed the gravity model. Considering the sample characteristics, the model is estimated with the Poisson pseudo-maximum likelihood (PPML) method. The main material of the study is a panel data set covering the years 2001-2021 for ten countries, Cameroon’s main coffee export partners. The findings show that the GDP of importing countries, coffee export prices, and bilateral investment treaties (BITs) positively influence exports, whereas distance, exchange rates, and Cameroon’s GDP have negative impacts. The results highlight Cameroon’s logistics infrastructure deficiencies and the significance of stable, high-quality production. The Cameroonian government should implement policies to improve production quality and efficiency by expanding agricultural extension services and offering farmers input and investment incentives to address these challenges. Additionally, improving port efficiency will necessitate the digitalization of operations, implementation of data-driven planning, and strategic infrastructure investments.

 

Volume 0, Issue 0 (12-2024)
Abstract

Aim and Introduction
Today, the environment is considered as one of the most important pillars of sustainable development, and the development of other economic and social sectors depends on its sustainability and proper functioning. Environmental pollution has become one of the main challenges of countries. Environmental health is currently one of the most critical concerns of people and officials round the world. Almost all managers and decision makers believe that this national wealth should be protected not only for the current generation but also for future generations, since the pollutants caused by industries are highly costly and detrimental to health.
Active industries are one of the main sources of environmental pollution. One of the necessary conditions for economic progress and the introduction of extensive structural changes in economic and technological fields is industrialization and industrial development. In the production process, using production inputs whose main source is the environment, in addition to desirable outputs such as consumer goods, undesirable outputs such as environmental pollutants are also produced. If the number of outputs is not controlled and disproportionate, the losses from undesirable outputs will be greater than the benefits of desirable products in such a way that damages to the environment would be irreparable and sustainable development less likely to be achieved.
One of the most important concerns related to industrialization is the effects and environmental consequences of industrial activities. Therefore, achieving the necessary solutions to control such consequences is vitally important. Minerals are essential for human survival, but their extraction and processing are not environmentally friendly practices which contribute to problems such as soil erosion, air and water pollution. On the other hand, mineral sector is one of the largest energy consumers which has active contribution to air pollution and global warming. The main purpose of this study is to investigate the economic effects of Gol Gohar mine in Sirjan. For this purpose, it is intended to determine the type and amount of pollutants released from this complex, and also to determine the amount of the green tax of the complex as a solution to reduce pollution and examine the social welfare resulting from reducing pollution.
Methodology
In this study, the economic effects of environmental pollutants of Gol Gohar Iron Mine in Sirjan (Southeastern Iran), is investigated using the input distance function model from 2001 to 2022. Through calculating the shadow price of pollutants, a criterion for determining the green tax is determined, and then the amount of social cost resulting from the emission of pollutants is calculated.
The shadow price of the undesirable output is the cost that the producer must bear if they plan to reduce the production of the undesirable output. In fact, it can be interpreted as the marginal cost of reducing pollution for each producer. Therefore, the shadow price of the desirable output is considered positive and equal to the market price of that output, but the shadow price of the undesirable output must be estimated to be less than zero.
Findings
The products of Gol Gohar Iron Ore Complex in Sirjan, include granulated iron ore, iron ore concentrate and pelletized in the production process. The most greenhouse gases and air pollutants are related to carbon dioxide (CO2), sulfur oxides (Sox), nitrogen oxides (Nox) and particulate matter (SPM). According to the obtained results, the average shadow price for air pollutants in Gol Gohar complex for CO2, Sox Nox, and SPM was calculated as 11.15, 3,074.5, 5,529.62, and 1,875.62 rials per kilogram respectively. Moreover, the average total social costs resulting from the production of Gol Gohar Sirjan Complex was calculated as 92,710 billion Rials according to the amount of pollution produced over the period.
Discussion and Conclusion
The estimation of environmental costs is actually an introduction to providing solutions for internalizing and reducing environmental costs, using the input distance function model and the shadow price of environmental pollutants in the industrial and mineral complex of Gol Gohar, Sirjan. The title of the largest producer of iron ore in the country was calculated, and the social cost resulting from the emission of pollutants was also evaluated. Finally, in this study, solutions and mechanisms for reducing environmental costs have been proposed.
Considering that the ability to absorb pollutants by the environment is limited, the shadow price of pollutants, which represents their real social cost, should be taken into consideration. The damages should also be determined based on the shadow price of the pollutants. In other words, the amounts of pollutant emission should be calculated and while taking into account the allowed limit of pollutant emission and shadow prices, based on a legal plan, the environmental costs should be reimbursed. Taking such measures would surely require more studies and capable executive management system


Volume 0, Issue 0 (12-2024)
Abstract

  Aim and Introduction
Ecological footprint accounting is composed of two metrics, the “demand-side” (ecological footprint) and the “supply-side” (biocapacity). While the ecological footprint calculates the demand for natural assets in global hectares, biocapacity symbolizes the supply capacity of nature to meet this demand with the same unit of measurement. Ecological deficit also shows the difference between ecological footprint and biological capacity. Globally, the degree of ecological deficits continued to expand over the last decade due to the increase in EF and reduction in biocapacity, which is caused by the following: increasing consumption of fossil fuel energy, overexploitation of natural resources, unsustainable production methods, and economic activities.
Iran is one of the countries that has a weak environmental performance. According to the Global Footprint Network, Iran's ecological footprint exceeded 333% of its biological capacity in 2022. Iran's ecological deficit, which was - 0.55 global per capita hectares in 1961, has increased by 554% to 2.50 global per capita hectares in 2022, and the destruction and pollution of the environment in Iran have reached unsustainable levels. Therefore, the analysis of the determinants of environmental quality can provide insights into the design of appropriate environmental policies in Iran. 
In this regard, the environmental effects of dependence on crude oil have attracted considerable attention. Crude oil is an important and largest source of energy, especially for developing countries such as Iran. It is a fossil-based fuel and a major source of carbon emissions in the world. Hence, many studies have linked oil price shocks to environment quality. In contrast to oil-importing economies, where oil price increases encourage a shift to cheaper and cleaner alternative energy sources, the environmental policy issue in oil-exporting countries is entirely different. Indeed, a fall in oil prices may be associated with a decreased investment in environmentally friendly energy sources. By comparison, an increase in oil prices revealed a reluctance to diversify the economy away from its reliance on non-eco-friendly fossil fuel energy.
Based on the explanations above, the main purpose of this article is to investigate the asymmetric impact of scaled oil price impulses on the environmental Load Capacity Factor (LCF) in Iran using the Non-linear Autoregressive Distributed Lag (MATNARDL) approach. The paper intends to make the following contributions to the literature. Firstly, this article is the first to look into the effect of oil prices on the LCF in Iran by applying asymmetric methodologies. Secondly, it is the first study with a reverse load capacity factor as an environmental sustainability indicator. Thirdly, this paper applied the advanced and newly developed MATNARDL for asymmetric and nonlinear analysis to provide a more robust result that exhibits relevant policy implications. Finally, this innovative study investigated the effects of oil prices on the LCF in Iran between 1961 and 2022 in the framework of the LCC hypothesis.
Methodology
The study compiles annual data for the period 1961-2022 for Iran from three different sources. According to Statista, OP represents average annual OPEC crude oil price (in US dollars per barrel). The data are obtained from the World Bank, GDP per capita, (constant 2015 dollars), Energy Consumption (EC) as kg of oil equivalent per capita, Ecological Footprint (per capita, gha) and LCF (the load capacity factor) are obtained from Global Footprint Network. Because the LCF includes biocapacity in the numerator and EF in the denominator, it allows for simultaneous environmental assessment on the supply and demand sides. A higher LCF indicates a better environment. The current paper's economic functions are illustrated in Equations (1):

LnLCFt=fLnOPt, LnGDPt,LnGDPt2,LnECt,εt                                               (1)
The main objective of this study is to examine the major, medium and minimal scales of positive and negative changes in oil price on the environmental quality index in Iran. For this purpose, the MATNARDL is used as an estimator to examine the effect of minor to major adverse shocks and minor to major positive surprises in the explanatory variable on the explained variable.
Findings
The bounds cointegration test results confirm a long-term relationship in the asymmetric model. The estimation of the model has been performed by categorizing the positive and negative impulses of the oil price in three small (quantiles less than the τ30 threshold), medium (quantiles between the τ30 and τ70 thresholds), and large (quantiles greater than the τ70 threshold) scales in the form of MATNARDL approach. The results indicate that in the long term, small scale of positive (negative) oil price impulses had a positive (negative) and significant effect on the load capacity factor; while these impulses have a negative effect on the load capacity factor in the long term in both medium and large scales. Based on other results, energy consumption has a negative and significant effect on the load capacity coefficient, and the environmental hypothesis of the load capacity curve (LLC) in Iran is confirmed.
Discussion and Conclusion
Based on the obtained results, it can be said that the effect of oil price on the load capacity factor in Iran is asymmetric. Among positive impulses, only with increase in small scale of oil price, we can see an increase in load capacity factor and environmental sustainability in the country. Moreover, the positive impulses of the oil price on both medium and large scales lead to the increase of environmental instability by prioritizing economic achievements and activities over environmental issues
  


Volume 1, Issue 1 (7-2004)
Abstract



Volume 1, Issue 1 (9-2003)
Abstract

This article is an effort to recognize the devil of  “Az”_avarice- and its significance in Greek mythology and Zoroastrian texts as well as the worthy masterpiece of Ferdowsi_Shahnameh_ and the evil nature of this mighty and powerful devil the ways of fighting with whom have been discussed in some mythological and Zoroastrian sources.
The importance of Az’s presence in Shahnameh has been dealt with based on certain verses of Shahnameh . The author has tried his best to besides unveiling the avarice of a number of kings and heroes mentioned in Shahnameh, highlight the deceit of this treacherous evil. Those kings who successfully resisted the deceit of the devil and promoted justice, goodness and generosity have been introduced in the article as well.
In a nutshell, the article differentiates between avarice and greed and making the best of what life offers and other such issues.


Volume 1, Issue 1 (3-2023)
Abstract

Rice farmers in the study area as elsewhere in some developing parts of the world have been negatively affected by floods annually. There have been several solutions, some suggested and others implemented to mitigate the effect of these floods on the farmers. Different initiatives have been undertaken by various stakeholders in the food production chain. Providing a multidimensional approach to highlighting these initiatives is essential to an effective and efficient resolution. The prospects and challenges of incorporating technology, capacity development, business and government support have been evaluated. The solutions proposed in this paper would bring economic benefits to the rice farmers, private companies, and government, leading to the attainment of Sustainable Development Goal (SDG) 2- Zero Hunger and the other 16 SDGs.
 

Volume 1, Issue 3 (9-2012)
Abstract

The dry bubble disease, caused by Lecanicillium fungicola, is an important fungal disease of white button mushroom in Iranian mushroom production farms. Twenty-three isolates of the pathogen collected in Iran and identified as L. fungicola var. fungicola, were compared for genetic polymorphism, diversity in growth rate and virulence. Ten Universal Rice Primers (URP) were used to evaluate the genetic diversity of L. fungicola var. fungicola. URP analysis showed that the genetic diversity of Iranian isolates was low (average 10 % over the 10 primers used) and that they were almost clonal. Relative correlations between geographical origins of isolates and molecular grouping were observed but there was no correlation between mycelial growth rate, virulence assays and URP patterns. Significant differences were observed between isolates based on mycelial growth rate and virulence assays. The high level of genetic homogeneity is attributed to the effect of fungicides used for control of the mushroom diseases which might have imposed a significant selection pressure on the fungal populations.  

Volume 2, Issue 4 (12-2013)
Abstract

Rice blast, caused by Pyricularia grisea, is one of the most important diseases of this crop in Iran and all over the world. To evaluate the relationship between spore population (SP) and meteorological factors, SP was measured daily using spore trap during growing seasons of 2006-2008 in Rasht and Lahijan regions (Guilan province, Iran). Weather data including precipitation, daily maximum and minimum temperatures, daily maximum and minimum relative humidity and duration of sunny hours were obtained from weather stations which were five kilometers away from the fields. The relationship between spore population and metrological factors was evaluated by Neurosolution 5.0 software. Weather data and spore population were considered as input and output data, respectively. In this study, multilayer perceptron neural network, regression model and Log(x + 1) transformation were performed. To evaluate the model efficiency, correlation coefficient and mean square error were used. The results showed that the correlation coefficient (r) and mean square error (MSE) parameters were 0.55 and 0.03 in Rasht and 0.1 and 0.03 in Lahijan, respectively. The results also showed the potential of this model for modeling SP using meteorological factors; however more data is needed for validation of this model. There has been no previous report on modeling the relationship between SP and meteorological data using artificial neural network in Guilan province (Iran).

Volume 2, Issue 4 (10-2000)
Abstract

Laboratory experiments were performed to determine the effect of various scarification treatments at four temperature regimes on germination of licorice seeds . A randomized complete block design with four replications was used. Germination counts were made every day for 2 weeks. At 50C, none of the chemically and mechanically scarified and non scarified seeds germinated. At 15, 25, and 350C, mechanical scarification increased seed germination to 94-98%. However, at these temperatures, velocity of germination of mechanically scarified seeds were lowest among all treatments. Chemical scarification also increased germination percentage significantly to 90-95% with 45 min soaking. At 15 and 250C, seed germination percentage and velocity of germination increased as the soaking time in sulfuric acid increased from 5 to 30, 45, or 60 min. However, at 350C, there was no difference in germination percentage between soaking times of 5 and 60 min. It appears that soaking for 45 min provides full germination at 25 and 350C.

Volume 3, Issue 2 (4-2001)
Abstract

Projected global climate change may have a major influence on crop yield. The likely effects of climate change caused by increasing atmospheric carbon dioxide levels on rice yield in Iran were evaluated using a mechanistic growth model for rice, GSAC-rice, running under a climate change scenario predicted for a doubled-CO2 (2xCO2) atmosphere by the Geophysical Fluid Dynamics Laboratory (GFDL) General Circulation Model (GCM). Simulations were run for two locations with contrasting climates, one in the north (Rasht) and one in the south (Ahwaz) of Iran. GFDL predicted that as a result of doubling CO2 , temperature increases by 4.5 and 4.6 0C during the rice growing season in Rasht and Ahwaz, respectively. Changes in solar radiation are minor, but rainfall during the rice growing season decreases by 38.8% (102 mm) for Rasht and 68.2% (5.8 mm) for Ahwaz. It was predicted that doubling [CO2] alone increased rice yield by 30%, but that yield decreases by 3.7 and 11.6% for each degree centigrade rise in temperature in Rasht and Ahwaz, respectively. As a result of the combined effect of both doubling [CO2] and the climate change accompanying it (predicted with GFDL), 8% greater rice could be produced in Rasht, but irrigation needs would be increased dramatically by 57%. In Ahwaz (the south of Iran), rice production could be halved and might not even remain a viable option unless plant breeders are able to produce more heat tolerant rice cultivars. It was concluded that rice production in the north and south of the country would change dramatically.

Volume 3, Issue 4 (12-2012)
Abstract

Although linguists have been studying the “News” as a type of text for a long period of time, the researches have been mainly of the product-oriented types, which purely analyze the news texts and their linguistic characteristics. Linguists and media researchers have been mainly keen to determine sets of criteria known as “News Values” so far, and the result is various lists of media and linguistic news selection norms. The goal of this article is finding answer for the following questions: How news production process can be orchestrated in a linguistic model? What are the linguistic news values? and How these linguistic values correlate with other selection criteria? In addition to revisiting the theoretical notion of “News Values” and introducing the “Grice Maxims” as the linguistic criteria of news composition, this paper, as a descriptive analytical study based on field work, also represents the multi-level model of news composition and selection based on linguistically oriented findings. The mentioned model not only determines and explains different levels of news composition and selection process from the event to the news, but also puts the role of macro-structural elements of news discourse production such as ideology, relations of power and composition in the center of attention.

Volume 3, Issue 9 (7-2006)
Abstract

Experimental infrared dryer was used to study the effect of rough rice temperature and air velocity on grain crack during infrared radiation and convection drying. Factorial experiment with Completely Randomize Block design was applied to the experiment at three temperature levels of 45, 60 and 75°C (equal to radiation intensities of 0.19, 0.39 and 0.58 W/cm2) and two inlet air velocity levels of 0.4 and 0.6 m/s. The result showed that the rough rice temperature (radiation intensity) and air velocity had significant effect on crack losses. Increasing the radiation intensity and decreasing air velocity caused to increase of crack percentage during drying of rough rice samples. The comparison of infrared and convectional drying method showed that grain cracks with infrared drying energy at 60 and 75 °C (0.39 and 0.58 W/cm2) were less than that with convection drying at the same temperatures. But it did not have a significant difference at 45 °C (0.19 W/cm2). The mathematical model relationship of grain crack percentage with rough rice temperature and air flow velocity was derived. Also the result show that the effect of rough rice temperature was more than air velocity on grain crack in infrared radiation drying.

Volume 3, Issue 11 (12-2006)
Abstract

Quasi-static compressive tests to determine the mechanical properties of individual brown rice kernels were conducted on whole kernel rice of Hashemi and core specimens of Khazar varieties. The magnitudes of the failure force, failure deformation, breakage energy and apparent elasticity modulus for Hashemi kernels were determined at two moisture content levels, namly, %11 and %17 (w.b.) at four levels of loading rates ranging from 1 mm/min to 5.5 mm/min. For the Khazar variety, the magnitudes of failure stress and strain, as well as toughness and elasticity modulus were determined at moisture content of %14 (w.b.) for five levels of loading rates ranging from 0.5 mm/min to 1.5 mm/min. Statistical analysis of the test results showed that deformation rates had no significant effect on the mechanical properties. Moisture content had a significant effect on all grain mechanical properties. Decreasing moisture content caused significant increases in all these properties. The failure force and the breaking energy for Hashemi kernels increased more than double, when the moisture content decreased from 17% to 11%. The magnitudes of failure force and breaking energy varied from 56 N to 115.7 N, and from 2.01 mJ to 5.23 mJ, respectively. The means of apparent elasticity modulus for compressive test on the core specimens was calculated to be 1.762 GPa at 17% moisture content and 2.835 GPa at 11% moisture content. Compressive strength and apparent elasticity modulus for Khazar variety were determined to be 36 MPa and 973.4 MPa, respectively. Some of the mechanical properties compared well with the published data.
Mona Rajabian Miri, Masoumeh Shayanmehr, Majid Mirab-Balou,
Volume 4, Issue 1 (3-2018)
Abstract

The objective of this study was to identify the species of thrips associated with rice crops in order to determine population fluctuation of the dominant species. Studies were conducted during the month of April to August in the year 2017 form different growth stages of rice in Babolsar city, Mazandaran Province (Northern Iran). Samplings were done from four fields located at two sites, KeyxaMahalle and MirBazar. A total of seven species of thrips belonging to four genera and two families (Thripidae and Phlaeothripidae) were identified. Amongst them, Haplothrips eragrostidis Priesner was the dominant species accounting for 75.47% in abundance. This was followed by Thrips hawaiiensis Morgan comprising 6.47%. The other species include Anaphothrips sudanensis Trybom, Frankliniella intonsa (Trybom), F. tenuicornis (Uzel), Thrips tabaci Lindeman and Haplothrips flavicinctus (Karny) which comprised of4.85%, 4.32%, 4.31%, 4.04% and 0.54% respectively. The maximum number of thrips species was found in the middle of July and minimum in the month of May. Assessment of thrips abundance in rice fields were started at the beginning of dough stage and were continued until complete maturity.

Volume 4, Issue 2 (7-2013)
Abstract

The speech act of promise can be accompanied by two other speech acts: encouragement and pledge. Since, in this speech act, we have the concept of volunteer promise, and the speaker willingly makes a commitment to his/her addressee, according to George Austin's typology of speech acts, this speech act is considered to be an instance of commissive speech acts. Moreover, since the main features of performative verbs, i.e. “I, you, here and now”, are present in promises, promise is also regarded as a performative act. In political promises, given the objectives of the discourse as well as the personal traits of the speaker, Grice's maxims – quality, quantity, relevance and manner – may be violated. In a political promise, there may be as much brevity as there is repetition. Most of political promises serve merely as advertising goals and are not intended to be fulfilled. The maxim of relevance is generally heeded in political promises and the violation of this maxim before elections is fairly rare. Political activists usually make use of efficient and influential manner of speech in their election campaigns.   

Volume 4, Issue 2 (9-2013)
Abstract

Sheath blight, caused by Rhizoctonia solani AG1-IA, is one of the most destructive disease. Conventional methods of disease control using fungicides may develop new problems. Therefore, understanding molecular mechanisms of plant–pathogen interaction is necessary to adopt effective approaches for managing the disease. Here for the first time, by using bioinformatics tools and RT-PCR analysis and sequencing confirmed the presence of a Magnaporthe oryzae Avr-pita gene orthologous sequence designated as Rhiz-pita1 gene in three different geographic isolates of R. solani AG1- IA( A2,R1 and T2) genome. SignalP program predicted a secretion signal upstream of Rhiz-pita1 gene. Nucleotide sequences of 5' region of Rhiz-pita1 gene from geographical isolates showed 99% identity in exons and 100% in introns which are characteristics of fast evolving effector proteins. Also, 98% homology between Rhiz-pita and M.oryza-pita1gene suggests that Rhiz-pita encodes an effector protein. Howevere, more researchs are necessary to confirm of this suggestion. Keywords: Rhizoctonia solani, signal peptide Rice blast , Effector

Volume 4, Issue 3 (7-2002)
Abstract

An efficient system has been developed for the reproducible regeneration of plants from cell suspension-derived protoplasts of the two commercial Iranian Japonica rice cultivars Tarom and Khazer. Friable embryogenic calli were used for cell suspension initiation and protoplasts were isolated from both varieties. When embedded in agarose, proto-plasts failed to divide. However, sustained divisions were obtained by using nurse cells of Lolium moltiflorum. Plant regeneration was 21.1% and 10.5% for Tarom and Khazer, re-spectively. Somaclonal variation was observed amongst regenerated plants, 16.2% of re-generants were tetraploid, and the rest were diploid.

Volume 4, Issue 3 (12-2020)
Abstract

Research subject: The rice husk is the coating on a rice grain and a by-product of the rice milling process. In this study, the extraction of amorphous silica from this agricultural residue by thermal as well as acid/thermal treatment method was studied.
Research approach: The process was designed as follows: after burning the paddy in the open field, the obtained ash was washed with acid followed by drying. Finally, the amorphous silica was obtained by placing the prepared powder in an electric furnace (acid/thermal treatment). Also, a sample of silica was produced by eliminating the acid treatment step (thermal treatment). Afterward, the obtained silica powder was employed in a conventional passenger radial tire belt formula instead of commercial precipitated one, and whole the physical-mechanical properties, including rubber-to-wire adhesion force, were studied under normal and aging conditions.
Main results: The results of the XRD demonstrated that the silica produced in both methods were amorphous. The XRF analysis also showed that the purity of amorphous silica were 98.6% and 93.9% for the sample produced by acid/heat treatment and the heat treatment, respectively. The results of the tire test showed that the rubber-to-wire adhesion decreased slightly under normal conditions in the presence of new silica samples, but the same property under the timed conditions for the new silica samples was better than commercial precipitated silica. Other properties of the rubber compound did not change significantly in the presence of new silica grades. As a result, it can be said that rice husk has a potential to produce suitable silica for use in blend of radial tire belt.

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