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Showing 28 results for darvishi


Volume 2, Issue 1 (9-2011)
Abstract

Lipase is used in the production of detergents, cosmetics, pharmaceuticals, flavour enhancers and foods. The lipase of yeast Yarrowia lipolytica can be used for production of important class of chemical intermediates in the pharmaceutical industry. Lipase production depends on media composition and environmental conditions. Y. lipolytica DSM 3286 strain was cultured on media containing different organic and inorganic nitrogen sources. Lipase production was investigated by measuring biomass and lipase activity was detected by ρ-nitrophenyl laurate (PNPL) spectrophotometric assay method at various times within a period of 7 days. In this study, the effect of different nitrogen sources was investigated on Y. lipolytica DSM 3286 lipase production. The maximal lipase production (34.7 U/ml after 48 h) was detected in medium containing yeast extract as nitrogen source. The optimum temperature and pH of the enzyme activity were 37 °C and 7, respectively. The final goal of this study is to develop and optimize lipase production by Y. lipolytica for use in pharmaceutical industry.

Volume 9, Issue 1 (Winter 2020)
Abstract

Aims: Monitoring of the fish biomass is one of the basic principal of fisheries management, but ornamental and reef fish stocks, because of difficulty of estimating their abundance, have been less studied than others. The aim of this study was to estimate the standing biomass of ornamental and reef fishes in Larak Island, in the Strait of Hormuz.
Materials &Methods: Standing biomass of the fish species was assessed seasonally using Underwater Visual Census Method (UVCm) in coral reefs and  mesophotic coral reefs in Larak Island throughout 2018 and 2019. Two popular methods in UVCm (belt transect and stationary point) were used based on topography of sea bottom. The confidence interval of estimated standing biomass is calculated using bootstrapping method.
Findings: The standing biomass of ornamental and reef fishes is estimated as 2522.18, 5222.17 and 1325.15(Kg.) in Site 1, Site 2 and Site 3, that are located in 3-15meters depth. The standing biomass at Site 4, was estimated as 884.13kg. The minimum were observed in summer, also the result showed  that the standing biomass in summer was significantly lower than other seasons (P <0.05). In addition, the temporal diagnostic test showed that population structure of fish in the spring, autumn, and winter seasons was similar but significantly different from the population structure in summer.
Conclusion: The less of standing biomass in summer season can be affected  by seasonal migrations of fish in tropical and subtropical waters to deeper waters, in order to trade of the stresses caused by temperature fluctuations.
 

Volume 10, Issue 2 (Spring 2019)
Abstract

Maize (Zea mays L.) is one of the most cultivated crops worldwide, owing to its versatility and wide adaptability, and serves as food, animal feed, and raw material for various industrial products. The purpose of the current research was the classification of maize inbred lines in order to produce hybrid seeds based on agro-morphological traits. Each of 100 maize inbred lines was planted in 6 pots as 6 replications and arranged in completely randomized design in an open area near to greenhouse in 2015. The result of the analysis of variance revealed significant differences among lines for all studied traits. The highest correlation was seen between cob’s length and cob’s weight. Stepwise regression analysis revealed that 66.4% of seed yield per plant variation was determined by cob’s length and cob’s weight. Cluster analysis divided inbred lines into 4 groups. The highest Mahalanobis distance (28.07) was observed between cluster 2 and 4. The result of principal component analysis confirmed the calcification by cluster analysis. The genotypes from groups 2 and 4 can be potentially used as parental lines in hybrid varieties production and development of segregating populations.


Volume 10, Issue 4 (12-2021)
Abstract

 This study was conducted to investigate the possible effects of cages culture Asian sea bass fish (Lates calcarifer) on the population structure of macrobenthos in the Rigo area of Qeshm Island in Hormozgan province during a breeding period in 1397 were investigated. The average abundance of macrobenthos at the location of the cages culture and the refrences site in this study was equal to (52765 ± 19154 in m2) and (50642 ± 21002 in m2), respectively.The results showed that at the time of the study among the identified the genus of Ammonia sp. With a relative abundance of 73.41 percent at the location of the cages compared to the control station and Archasterope sp., Spirolochulina sp. and Nephtys sp. with a relative abundance of 63.9%, 49.1% and 12.6%, respectively, were more dominant in the control station compared to the location of the cages.The loading rate of organic matter in the bed of the cages was significantly affected by fish farming activities and in some times showed a significant difference with the control station (P<0.05). In general, at the time of the study, activities related to fish farming in cages had no effect on the population structure of macrobenthos in the study area.


Volume 11, Issue 3 (8-2022)
Abstract

Estimation of coral fishes biomass is needed as a basic benchmark for assessing the ecological status and fishing potential of coral reefs. Different methods are used to sampling the biomass of these communities, that direct observation is one of the preferred methods with respect to the non-destructive advantage. The purpose of investigation was to estimation standing biomass of coral fishes by Underwater Visual Census method (UVCm) in Abu-Musa Island seasonally from October 2019 to September 2020. also confidence interval was calculated of these estimations from the bootstrapping test (95%). Standing biomass of Coral fish and their confidence interval (95%) by bootstrapping simulation (n=479) were determinated 2923.6 kg., 4576.2 kg, and 1645.4 kg for the stations one, two and three respectively. The difference in the biomass standing of coral fish in three station could be related to the lack of differences in the amount of developed reefs, coral communities and significant differences in habitat availability.  Also, the standing biomass of coral fishes in the Abu-Musa Island are limited, that can be attributed to their low habitat, shortage of carrying capacity and the short life of the Persian Gulf basin, and stress that occurs in the ecosystem, especially bleaching events, that need more study in the future.

Volume 12, Issue 1 (Issue 1 (Tome 56)- 2008)
Abstract

By the increasing rate of flexibility in management systems including compensation systems, it is necessary to study theoretically and understand the key variables on designation of flexible compensation systems. Purpose – The purpose of this article is to study the ability of agency theory in explanation of compensation problems inrollving the cultural context and occupation features in Iranian Automotivie Induslry. Design/methodology- In this article, a conceptual model was developed in which we examined the relation of independent variable (agency theory assumptions) and dependent variables (current structure of compensation contracts and agent's tendency to arrange this structure). this relation is interfered with moderate variables (cultural dimensions and kind of occupation). In order to test the hypothesis, two active firms in automotive industry (manufacturing and service companies) were selected for sampling. It is to be mentioned that agency theory assumptions have not been examined in Iranian Automantive ludustry. Results –Test of hypothesis confirmed lots of agency theory assumptions. our findings showed that some of agency theory predictions are attenuated by cultural characteristics and most of time there is a significant relation between agency theory assumptions and occupation conditions. Conclusions - using agency theory assumptions with respect to cultural dimensions and occupation dimensions and occupation conditions in drawing up of compensation contracts will improve Iranian firm’s wage and salary systems in order to reduce agency problems and the related cost.

Volume 12, Issue 1 (12-2022)
Abstract

 In this study, the possible impact Asian sea bass fish (Lates calcarifer) cages culture on the population structure of phytoplankton in the coastal waters of Qeshm Island.Water sampling was done monthly for a period of six months in three stations from October 2018 to March 2019.The results showed that the mean Variations of total abundance of phytoplankton at the location of fish cages culture compared to the Reference station had a significant increase (P <0.05). At the location of cages culture, the Trophic status level was high (<5), the risk of eutrophication status (<4) and the value of trophic efficiency coefficient were high. According to the analysis of Simper test, Among the Forty-one genera identified, Noctiluca sp. with a relative abundance of % 82.37, contribution rate of 21.8% with high algal bloom at the location of cages in autumn season and then the genera Chaetoceros sp., Nitzschia sp. and Coclodinium sp. with a relative abundance of less than 10 percent in differentiating the population structure of phytoplankton have played a significant role in the dissimilarity of the population structure of phytoplankton between stations In general, in this study, the effects of fish farming activities on the population structure of phytoplankton are ineffective, but it causes the abundance of some species, available nutrients, increases the trophic level, and the probability of harmful algal blooms in the location of the cages culture.
 

 

Volume 12, Issue 3 (summer 2021)
Abstract

Nowadays, aromatic componds are widely used in food, pharmaceutical, cosmetic and chemical industries. Due to the growing tendency of consumers to use natural products, biotransformation by microorganisms is an interesting method for the production of aromatic compounds. Gamma-decalactone is a cyclic aroma with a peach-like flavor. The non-conventional yeast Yarrowia lipolytica can bioconversion the inexpensive castor oil substrate into the valuable gamma-decalactone. The process begins with the hydrolysis of castor oil by the lipase to ricinoleic acid, then continues by shortening the chain by beta-oxidation, and finally ends by lactonization. In this study, gamma-decalactone production was optimized via Response surface methodology (RSM) by a mutant strain of this yeast with the ability to produce high amounts of lipase. For this purpose, castor oil, yeast extract, peptone and pH were studied as factors at five levels. Based on statistical analysis of the relationships between the experimental variables, a mathematical model was obtained for the governing relationships between the experimental variables. Based on the results, the best values were obtained for castor oil 35 ml/l, yeast extract 6 g/l, peptone 8.5 g/l and pH 4. To validate the mathematical model, the proposed values were tested and 126 mg/L of gamma-decalactone was produced by the yeast strain, which shows a 46% increase compared to non-optimal conditions. The results of this study can be used to make cost-effective production of gamma-decalactone from castor oil by microbial biotransformation process.

Volume 12, Issue 3 (9-2023)
Abstract

The present study was conducted in order to obtain the necessary information on the diversity, abundance and distribution of macroinvertebrates, as well as to investigate the grazing status of batoid fishes (stingrays) from benthic macroinvertebrtes in coastal waters of Hormozgan province. For this purpose, sampling was done in the years 2017 and 2018 and once every year in the autumn season. At the end of the identification process, a number of 125 genus and 104 species belonging to 85 families, 31 classes, 9 orders, and 7 phyla were successfully identified. Results revealed that Malacostraca was the frequent order in the studied area. In order to investigate the possible relationship between composition and abundance of benthic macroinvertebrte and stingrays, CCA analysis was employed. Results of stomach content of stingrays revealed that in the diet of M. randall, crustacean (93.25 %IRI) has the highest amount. This pattern was the same for M. gerrardi and H. walga. However, in M. gerrardi, bivalvia were in the first place of importance (31.33 %IRI). Also, trophic level analysis was done for three species which shows all species are Mesopredators that place in the same level of food web. According to the mentioned cases, some benthic macroinvertebrates identified in this research have a significant  relationship with the benthic fishes, which requires more studies to investigate their relationship.
 

Volume 12, Issue 4 (12-2023)
Abstract

  Trichiurus lepturus is one of the most important and commericial species in the Persian Gulf and Oman Sea.In order to come up with the responsible fishing pattern,there was a need to identify  reproduction characteristics. Data were collected randomly from April 2019 to February 2020 from six major artisanal fish-landing sites in Hormuzgan Province (Bandar Parsian, Bandar Kong, Qeshm Island, Bandar Abbas, Bandar Sirik and Bandar Jask). In the detection of sexual stages, the 5-stage key of sexual maturity was used at the macroscopic level. In determining the spawning season, the gonado-somatic index(GSI) was used and its comparison in different months. The lowest GSI of female fish was in September (1.2). The highest GSI of male fish was determined in December with a value of 3.1 and after that in May 2.6. Examination of the GSI and reproductive stages showed two main spawning periods in the middle of spring and late autumn. Different sexual stages were seen in all months of the year, which indicated the batch spawning strategy in T. lepturus. During different months, significant differences in the sex ratio were observed, but during the investigation and in total, no significant difference was observed between the female: male sex ratio in the expected ratio of 1:1.The length at first maturity obtained 78.7 cm total length. It is necessary to ban fishing during the spawning season in order to protect the stocks of this species.
 

Volume 13, Issue 3 (10-2024)
Abstract

Tuna fishes are one of the most important and commericial tuna species in Northern of the Persian Gulf and Oman Sea. The tuna fish stocks Thunnus tonggol was assessed in Hormuzgan coastal waters using software FiSAT . Data were collected minimum 200 fish per month simple randomly from five major traditional fish-landing sites in Hormuzgan Province, from November 2021 to September 2023. The monthly individuals ranging of T. tonggol  from 21 - 108 cm fork length with mean 71.08 ± 1.23 cm.The infinity length and growth parameters (K, L∞) for T. tonggol, were computed 121.17 cm and 0.68 respectively. Growth performance index (Phi Monreo) calculated for T. tonggol , 8.9 which was in agreement with the finding of the other studies in the Indian Ocean. The results showed that this species has a high growth rate in the first 2 years of their life. The (a, b) parameters in power equation length-weight relationship for T. tonggol were (0.00002, 2.94), indicating that T. tonggol has isometric growth. Total mortality, natural mortality, fishing mortality rate and exploitation ratio (Z, M, F, E) were estimated for T. tonggol (2.89, 0.71, 2.18, 0.75). These results indicated that population of T. tonggol  is overexploited and no scope for improving production in Hormuzgan Province. Tuna fish stock are trans boundaries and its fishery management  and long term monitoring programs would be conducted in collaboration countries bordering the Persian Gulf, Oman Sea and Indian Ocean


Volume 13, Issue 4 (11-2024)
Abstract

The use of Artificial reefs(A.Rs) are one of the methods used to rehabilitation of fish stocks. This involves studying the grain size composition of bed sediments and  Total Dissolved Solids (TDS), which are crucial components in terms of their location. For this purpose, three stations with three repetitions were selected in the eastern and western of Jask City Bay and the study was conducted in the summer and winter seasons of 2023.In the study of total suspended solids, the minimum value with the mean and standard deviation was 25.9±0.46(mg/lit)at the fourth station in the Eastern basin during winter 2023. The maximum value with the mean and deviation was 36.39±0.62( mg/lit )at the third station in the western basin during summer 2023. The analysis of sediment grain size in the stations revealed that the lowest and highest amounts of sand and silt were found in the western basin at 76.4% (third station, summer 2023) and 88.5% (second station, winter2023) respectively. Firstly, the strength of the substrate (grain size) is the most essential factor in establishing structures, which contributes to ecological and biological success. Considering the optimal range of this component stations, suggested as the suitable areas for installation of A.Rs, one area(Western of  Jask City Bay) and two area(Eastern of  Jask City Bay), respectively. 


Volume 15, Issue 3 (5-2013)
Abstract

In this study, green pepper was dried by a laboratory scale microwave-convective dryer. The effects of microwave power on drying rate, effective moisture diffusivity, and energy consumption of green pepper were studied at four different microwave powers of 180, 360, 540, and 720W. The drying data were fitted to the four thin-layer drying models. The moisture reduction of the green pepper samples, from 2.894 to 0.1 kg water kg-1 dry matter, lasted 120 and 495 seconds at microwave power of 720 and 180W, respectively. The drying model assessment revealed that the Midilli model exhibited the best performance in fitting the experimental data, providing the highest R2 (0.927), and the lowest RMSE (0.2065) and χ2 (0.0555). With increase in microwave (drying) power from 180 to 720W, moisture diffusivity increased from 6.249×10-9 to 3.445×10-8 m2 s-1. Results also indicated that drying rate increased by increasing the microwave power and decreased continuously with passing of drying time and decreasing moisture content. The least specific energy consumption (7.2 MJ kg-1 water) was at microwave power of 360 W and the highest (9.26 MJ kg-1 water) was at 540W.

Volume 16, Issue 4 (1-2013)
Abstract

Today ICT is growing remarkably and considered as a very important enabler in different enterprises , and then, reaching the goals of an organization is almost impossible without it. The aim of using ICT is to achieve the business goals and ensure following the strategies. Therefore the organizations should benefit from ICT solutions to move toward their goals, using ICT solutions effectively, but without having appropriate processes will be a very difficult job. according to COBIT, As the IT Governance provides a structure for connecting IT processes and relating information to enterprise goals, strategy and business requirements, and it integrates optimized methods of IT planning and organizing, acquiring and implementing, delivery and support, monitoring and evaluating for dual goals of risk management ( for making the confidentiality, availability, reliability and compliance) and acquiring benefits and advantages ( efficiency and effectiveness) ,first, the maturity level of enterprise processes of information and communication technology (ICT) organization of Isfahan Municipality has been assessed in this paper by using this framework and then a new aspect of COBIT and the relations between its different components are discussed. Finally considers the following question: Does the rising of maturity level of enterprise processes lead to increase the meeting of the business requirements?

Volume 16, Issue 5 (9-2014)
Abstract

The present study investigated the influence of air temperature and velocity on the drying kinetics and specific energy consumption during fluidized bed drying of soybean at 80, 100, 120 and 140ºC and airflow rates of 1.8, 3.1 and 4.5 m s-1. Six mathematical models for describing the fluidized bed drying behavior were investigated. The value of the drying rate coefficient (k) increased with increasing air temperature and velocity and thus reduced the drying time. Although the Midilli model showed the best fit, the Page’s model was selected, since it had almost a similar performance but the model is simpler with two parameters instead of four. The drying of soybean seeds took place in the falling rate period and was controlled by moisture diffusion. A third order polynomial relationship was found to correlate the effective moisture diffusivity with moisture content. Effective diffusivity increased with decreasing moisture content and increasing temperature and air velocity. It varied from 4.595×10−11 to 3.325×10−10 m2 s-1 over the temperature and velocity ranges. Values of the activation energy for moisture diffusion were determined as 35.33, 32.85 and 30.73 kJ mol-1 for air velocities of 1.8, 3.1 and 4.5 m/s, respectively. It was found that decrease in energy of activation caused an increase in drying rate. The minimum and the maximum specific energy requirements for drying of soybean seeds were determined as 26.90 and 111.05 kWh kg-1 for 140ºC with 1.8 m s-1 and 80ºC with 4.5 m s-1 air velocity, respectively.

Volume 17, Issue 104 (October 2020)
Abstract

Today, pectin is widely used as gelling agent and stabilizer in the food industry. The present study, pectin extraction from dried powder of peel and cap of pumpkin was performed in two different acidc and water solvents method. Finally, the samples that showed the highest pectin yield in each extraction method was selected for further experiments. Then, galacturonic acid percentage, degree of estrification, emulsifier stability, emulsifier activity, viscosity and FT-IR spectroscopy were applied to selected methods. The highest yield in acidic solvent (pH=2.5) in cap treatment of pumpkin (23.03%) and water solvent (for 3 hours) in cap treatment of pumpkin (17%) in 90 °C, 90 minutes and solvent to dry matter ratio 1:30 ml/mg was determined. According to the results, The highest percentage of galactoronic acid in pectin extracted from the cap treatment was observed in solvent acidc. The highest amount of estrification degree , emulsifiers stability and activity in pectin extracted from the peel treatment was observed in solvent acidc. Pectin extracted from cap treatment showed higher viscosity than pectin peel treatment. The viscosity of all solutions was used in the shear rate (0.05-200 r(s-1)) constant, which indicates the flow index (n) equal to 1 and the Newtonian behavior of the solution. 
Dr Bagher darvishi, Dr Mahdi Omidi, Bahareh Jani,
Volume 18, Issue 1 (Spring 2018 2018)
Abstract

Poverty decomposition provides useful information about the factors affecting poverty and helps the politicians to choose suitable poverty reduction policies. In this context, sectoral decomposition (Ravallion-Huppi, 1991) and growth–­equality decomposition (Datte- Ravallion, 1992) are the most widely used methods for poverty decomposition. But the ambiguous elements (such as residual and interaction terms) existing in these methods resulted in developing a new decomposition method by Fujii (2014). His decomposition method is residual-free and has some desirable properties including time-reversion consistency, and sub-period additivity. In the present study, following Fujii (2014) and using Iran’s rural and urban household expenditure and income data, the poverty is decomposed into six components: population shift (PS), within-region redistribution (WR), between-region redistribution (BR), nominal growth (NG), inflation (IF), and methodological change (MC). The results show that population shift (PS), within-region redistribution (WR) and inflation components explain the highest portion of the poverty changes in the urban and rural areas. Based on the results, the pro-poor growth policies and immigration-reducing policies are recommended for reducing rural poverty, while the growth-oriented policies with redistribution are recommended for decreasing urban areas.  In all periods, inflation is the main poverty-increasing factor in both urban and rural areas; therefore, controlling inflation can reduce poverty rates.

Volume 19, Issue 9 (September 2019)
Abstract

Heat transfer of polymeric foams is consisting of three different mechanisms including heat transfer through a solid phase, gas phase, and thermal radiation. Thermal insulation properties of polymeric foams are affected by different structural properties. Also, these structural properties have a different influence on the different heat transfer’s mechanisms. Therefore, it is necessary to use theoretical models. Several theoretical models have been presented so far, meanwhile, providing theoretical models that can estimate the thermal conductivity using the easiest measurable properties along with sufficient accuracy and reliability can be very helpful. In this regard in the present study, a theoretical model based on cell size and foam density is developed in order to predict the thermal properties of polymeric foams. It was concluded that the error of the developed theoretical model is lower than 8% in comparison to the experimental results. In the following, the effect of most important structural parameters i.e. foam density and cell size on the thermal conductivity is investigated. Based on the results, determining the optimum density is necessary to achieve the lowest thermal conductivity. Also, the gas thermal conduction has the most contribution to the overall thermal conductivity and achieving the nanometer cell sizes can be useful in order to decrease it.


Volume 19, Issue 126 (August 2022)
Abstract

Non-ionizing ultraviolet (UV) radiation is a kind of electromagnetic radiation that has been shown to be harmful to microorganisms such as bacteria, viruses, and fungus. The goal of this study is to evaluate the effective and hazardous features of this type of radiation in three regions (UVA, UVB, and UVC), using the approach of biological properties and applications in disinfection and sterilizing. In this research study, in order to be effective on microorganisms in the ultraviolet spectrum and its surroundings near the visible area, two test samples with commercial UVC and blue-LED lamps were used. In this study, the effect of ultraviolet C radiation on pathogenic microorganisms of Staphylococcus aureus and Pseudomonas aeruginosa in liquid environment and solid surface culture, the effect of ultraviolet C radiation on the total count (total count) of microorganisms on paper and mobile surfaces, and finally to The effect of UV LED on the total number of oral microbes attached to the toothbrush after brushing was investigated. In two tests performed with radiation in the ultraviolet region and near it in the visible region, the lethal effect on bacteria and microorganisms was concluded with more than 90% effectiveness and destruction of bacteria. Which indicates the effectiveness of such radiation in disinfecting, disinfecting and sterilizing equipment. Spectroscopic investigations of UV commercial lamps, as well as their efficacy on microbes, demonstrate the use of this sort of radiation, in addition to its biological hazards, which necessitate careful consideration of how it is utilized. In comparison to alternative sterilizing methods, the use of UV radiation in business and medicine is a cool, dry, easy, effective, and economical technique that produces no ionized radiation.


Volume 20, Issue 2 (3-2018)
Abstract

In this study, the influences of drying conditions on the mass transfer characteristics of kiwi slices are investigated using the analytical model proposed by Dincer and Dost. The experiments were conducted at temperature range of 50–80°C with 0.5 m s-1 air velocity for convective drying and in the microwave power range of 200–500W for microwave drying as single layers with sliced thickness of 3, 6, and 9 mm. The results show that the mass transfer characteristics strongly depend on the drying conditions. Through the convective drying method, parameters including moisture diffusivity, mass transfer coefficient, Biot number, and drying time were varying from 0.16-1.45×10-8 m2 s-1, 1.93-4.95×10−7 m s-1, 0.103-0.225, and 90-604 minutes, respectively. In comparison, for microwave drying, they were within the ranges of 0.66-25.60×10-8 m2 s-1, 0.62-5.64×10−5 m s-1, 0.960-1.742, and 4-23.5 minutes, respectively. Results reveal that the activation energy for moisture diffusion is higher than that needed for the convective mass transfer process.

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