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Hojjat Ahmadi

University of Tehran, Mechanical Engineering of Biosystems, Faculty Member

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Full Professor, University of Tehran, Especially in Condition Monitoring
Supervisors: University of Toronto
Address: Todonto, Canada

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Seyed Saeid Mohtasebi

University of Tehran 4

بهروز نیرومند

Karaj Islamic Azad University Of Iran

Likoundayenda Desti

Sharif University of Technology

Savitribai Phule Pune University

Bernard Akindade Adaramola

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Papers by Hojjat Ahmadi

A practical approach to electromotor fault diagnosis of Imam Khomaynei silo by vibration condition monitoring

African Journal of Agricultural Research, Apr 30, 2009

Practical experience has shown that vibration technique in a machine condition monitoring program... more Practical experience has shown that vibration technique in a machine condition monitoring program provides useful reliable information, bringing significant cost benefits to industry. The objective of this research was to investigate the correlation between vibration analysis and electromotor fault diagnosis. This was achieved by vibration analysis of an electromotor in Imam Khomaynei silo. The vibration analysis was initially run under regular interval during machine life. A series of tests were then conducted under the operating hours of electromotor. Vibration data was regularly collected. Overall vibration data produced by vibration analysis was compared with previous data. Numerical data produced by vibration analysis were compared with vibration spectra in standard condition of healthy electromotor, in order to quantify the effectiveness of the vibration condition monitoring technique. The results of this paper have given more understanding on the dependent roles of vibration analysis in predicting and diagnosing of electromotor faults.

Prediction Of Watermelon Consumer Acceptability Based On Vibration Response Spectrum

It is difficult to judge ripeness by outward characteristics such as size or external color. In t... more It is difficult to judge ripeness by outward characteristics such as size or external color. In this paper a nondestructive method was studied to determine watermelon (Crimson Sweet) quality. Responses of samples to excitation vibrations were detected using laser Doppler vibrometry (LDV) technology. Phase shift between input and output vibrations were extracted overall frequency range. First and second were derived using frequency response spectrums. After nondestructive tests, watermelons were sensory evaluated. So the samples were graded in a range of ripeness based on overall acceptability (total desired traits consumers). Regression models were developed to predict quality using obtained results and sample mass. The determination coefficients of the calibration and cross validation models were 0.89 and 0.71 respectively. This study demonstrated feasibility of information which is derived vibration response curves for predicting fruit quality. The vibration response of watermelon...

Surveying and Comparing Thermal Conductivity and Physical Properties of Oil Base Nanofluids Containing Carbon and Metal Oxide Nanotubes

Journal of Nanostructures, 2012

In this research, nano materials with tubular structures are added to SAE 20W50 engine oil to stu... more In this research, nano materials with tubular structures are added to SAE 20W50 engine oil to study the rate of their effects on the properties of engine oil. Multi-walled carbon nanotubes (MWCNTs) and vanadium oxide nanotubes (VONTs) has been used as two different additive materials, one of them is carbonic and the other is metallic oxides and their effect on different parameters containing viscosity, thermal conductivity coefficient, flash point and pour point of engine oil as the quality properties of engine oil has been studied and compared. The samples of two concentrations 0.1 and 0.2 wt% with using planetary ball mill were made. The obtained results show that MWCNTs in all cases, which have been evaluated, had better functionality with respect to vanadium oxide nanotubes. In the 0.1 wt% concentration, flash point of MWCNTs/oil and VONTs/oil increased about 9.3% and 5.8% respectively. In addition, thermal conductivity of them increased 13.2% and 10.2% respectively.

Experimental Research on Variation of Pore Water Pressure in Constant Rate of Strain Consolidation Test

Acta Geotechnica Slovenica, 2014

Constant rate of strain (CRS) consolidation is a rapid test method which is used for determinatio... more Constant rate of strain (CRS) consolidation is a rapid test method which is used for determination of compressibility of clayey soils. In a CRS test, the appropriate strain rate is selected based on pore water pressure ratio, i.e. the ratio of pore pressure to total stress. In the present study, to investigate the effect of strain rate on variation of pore water pressure ratio, four different clay samples of different plasticity were tested by CRS apparatus. The results of the experiments showed that the trend of variation of pore water pressure is dependent on the drained water flow regime which may be either Darcy or non-Darcy. The results also indicated that the plasticity of clay does not have considerable effect on variation of pore water pressure.

An Appropriate Approach for Misalignment Fault Diagnosis Based on Feature Selection and Least Square Support Vector Machine

A study is presented to diagnosis of misalignment fault using feature extraction and selection te... more A study is presented to diagnosis of misalignment fault using feature extraction and selection technique and support vector machine (SVM) classifier. The time-domain vibration signals of a compressor with normal and misalignment conditions in driven end (DE) are gained for feature extraction. The features are extracted by using the statistical and vibration parameters. Then stepwise backward selection is applied for selecting the significant features. The selected features are used as inputs to the classifier for two-class (normal or misalignment) identification. The roles of stepwise backward selection technique and SVM classifier are investigated. The results indicate the potential of the proposed intelligent method in misalignment fault diagnosis of the compressor.

Runoff and sediment yield modeling using WEPP in a semi-arid environment (Case study: Orazan Watershed)

Desert, 2011

Water erosion is a major environmental problem in many parts of the world. Majority of semi-arid ... more Water erosion is a major environmental problem in many parts of the world. Majority of semi-arid countries are concerned because of their specific climate and soils sensitivity, but also because of the recent intensification of human activities and agricultural practices. Accurate estimation of water erosion for various land-use and climate scenarios is so an important key to define sustainable management policies. In the last decades, several studies have been carried out to build models suitable for quantifying sedimentation. Among these models, the Water Erosion Prediction Project (WEPP), is a physically based, distributed-parameter model that has been developed and mainly validated in America. Only few studies have investigated its applicability to environmental conditions that differs from those where the model was developed. The aim of this work is to test the efficiency of WEPP model to predict runoff and sediment yield at catchment scale in a semi-arid area. Continuous simul...

Some Physical and Mechanical Properties of Iranian Wild Pistachio (Pistachio mutica L.)

Wild pistachio is oiling crop; therefore, physical and engineering properties are necessitate to ... more Wild pistachio is oiling crop; therefore, physical and engineering properties are necessitate to determine for processing and equipment design. In this study, some raw material characteristics were determined for Iranian wild pistachio (Pistachio Mutica L.), in order to collect information about identifying some physical and mechanical properties of them. The average grain length, width and thickness were 7.62, 8.84 and 6.42 mm, respectively. The geometric mean diameter, thousand grain kernel and aspect ratio were 7.86 mm, 302.28g and 1.17, respectively. True density, bulk density and porosity were 1.07 kg m , 0.5 kg m and 0.5%, 3 3 respectively while the static coefficient of friction varied from 0.44 on plywood surface to 0.56 on galvanized iron. The angle of repose for static and emptying were 52.5 and 28.86 degree, respectively. Whereas the failure force, elongation and energy were 143.07 N, 1.68 mm and 201.29 kPa respectively.

Development of a New Threshold Based Classification Model for Analyzing Thermal Imaging Data to Detect Fungal Infection of Pistachio Kernel

Agricultural Research, 2013

Thermal images have beneficial information which can be used for diagnostic purposes. The informa... more Thermal images have beneficial information which can be used for diagnostic purposes. The information can be released by applying appropriate analyses methods. In this research, a new algorithm, threshold based classification (TBC), was developed to analyze thermal images of healthy and fungal-infected pistachio kernels in MATLAB 2010 A environment. Results showed that TBC algorithm can classify successfully healthy and infected pistachio kernels without considering the infection stages.

An Assessment of Specific Sediment Yield of Geological Formations Using Investigated Sedimentary Deposits in Reservoirs and Fingerprinting

Journal of Agricultural Science and Technology

Sediment yield data, collected for most regions in Iran has been insufficient and not so reliable... more Sediment yield data, collected for most regions in Iran has been insufficient and not so reliable and there is still not any sufficiently reliable methodology available for sediment yield assessment in the country as a whole. On the other hand, an attainment of reliable sediment yield data is a must and key requirement for the design of effective sediment management as well as control strategies. Sediment deposition in reservoirs is assumed as a very useful tool in providing such data. The main objective of the present research was to discuss a combination of both source fingerprinting technique and reservoir sediment survey to provide reliable data on sediment yield of geological formations for three small catchments in Semnan Province, Iran. Throughout the study, the volume and mass of deposited sediments in reservoirs were initially assessed. Fingerprinting technique was employed to identify the contribution to, as well as the specific sediment deposition yield of each geological...

Application of Remote Sensing in the Agricultural Land-Use Assessment

The calculation of Normalized Difference Vegetation Indices (NDVI) can be very useful in the gene... more The calculation of Normalized Difference Vegetation Indices (NDVI) can be very useful in the generation of a land-use/land-cover classification. Calculation of a vegetative index (VI) from remotely sensed data can be used to quantify the amount of vegetation on the Earth's land surface. Numerous VI's exist, however the most commonly used VI is the NDVI. To detect the land-use and land-cover, the long term monitoring by the satellite images is useful as a big heritage. In this paper, the land-use assessment was investigated by using of the satellite images. After processing and exploitation of the data, the relation between bands was estimation and NDVI index were calculated. Then NDVI index with ground-related information was compared. Results showed that satellite images could detect the land-use changes in the local scale and vegetation index was suitable to estimate the land-use classification.

Determining the reliability function of farm tractors

There is an optimum time for implementing field operation of various crops in each region. If the... more There is an optimum time for implementing field operation of various crops in each region. If the operation is accomplished sooner or later, it will cause a reduction in yield quantity and quality. The cost of this reduction is named "timeliness cost". Annual timeliness cost is estimated by an equation reported in ASAE standards. MF285 tractors have low reliability in Iran. Generally, low tractor reliability has an uncertainty in implementation of farm operation which it is not considered in ASAE equation for calculating of timelines cost. This uncertainty causes a cost being a part of timeliness cost and is produced due to tractor failure within farm operation. The purpose of this study was to determine the reliability function of MF285 tractors operated in Debal Khazaei Agro-Industry Co. in Khuzestan province of Iran. Thus, in this study a function-fit model for reliability of farm tractors was determined. Afterwards, tractors working times to a failure (hours) in tenth year of tractor life were fitted with normal, exponential, lognormal, poisson and weibull age distribution functions using moment estimation. Depending on Chi square test, the best reliability function for this given situation was exponential distribution function with λ = 0.025.

Energy use and economic analysis of strawberry production in Sanandaj zone of Iran

The aim of this study was to determine the energy consumption and economic analysis for strawberr... more The aim of this study was to determine the energy consumption and economic analysis for strawberry production. The data were collected from 60 farmers growing strawberry in the Sanandaj zone of Iran by using a face-to-face questionnaire in August-September 2009. The plowing operation at the study area was done by two methods; manually plow (P 1) and machinery plow (P 2). Also the irrigation operation was done by two methods; pumping irrigation (P) and non pumping irrigation (NP). Univariate analysis of variance was used for finding the differences among the total energy used for production and profitability of this crop in the different methods at the 5% and 1% level. Total energy used in various farm operations during strawberry production was 53,605 MJ. ha-1. Total energy output was 17,338 MJ. ha-1 , and the average annual yield of strawberry farms was 9,125 kg. ha-1. Energy efficiency was 0.32, and energy productivity calculated as 0.17 kg. MJ-1. This means a production of 0.17 kg per unit energy. The difference between total input energy in the different irrigation types (NP and P) is significant at 1% level. There is not any significant difference between different plow types at the 5% level. The interaction of irrigation types and plow types is significant at 5% level. The profit-cost ratio, productivity, and net profit in the strawberry production are 1.2, 0.99, and 1,825 $. ha-1 , respectively. The difference between net return in the different irrigation types (NP and P) is significant at 5% level. The difference between net return in the different plow types (P 1 and P 2) is significant at 1% level.

Application of Vibration Response for the Nondestructive Ripeness Evaluation of Watermelons

The assessment of watermelon ripeness on the basis of its apparent properties, such as size or sk... more The assessment of watermelon ripeness on the basis of its apparent properties, such as size or skin colour, is very difficult as traditional methods have various problems and limitations. These include lack of uniformity, concentration of excitation energy within narrow bands and need for physical contact between a fruit and the measuring device. In this study a new method making use of Laser Doppler Vibrometry technology (LDV) has been applied to evaluate the ripeness of watermelons, without many of those limitations. At first a watermelon is excited by a shaker as vibration generating device within a range of frequencies. At the same time, the vibrating response of the upper side of the fruit is measured by LDV. The device emits a laser beam on a spot above the sample. The beam reflected from that point is received by the LDV and finally the vibration response of the sample is measured and the signal is sent to the computer. Using a fast fourier transform algorithm and the ratio of input to response signals, the frequency response of the fruit sample was processed and the desired results extracted. After the nondestructive tests were completed, the watermelon ripeness was evaluated by means of a destructive method. The sugar and firmness of the samples were measured as ripeness indices. In this study four modal properties were derived and used for developing predictive models to relate the vibration response results with the watermelon sugar and firmness. Interaction models by including the fruit mass were found more accurate than other common multiple models. The nonlinear regression model has five variables as sample mass, first and second resonant frequency and also damping ratios of them. For this model the coefficients of determination and the mean square error for the estimation of the fruit sugar were 0.9 and 0.79 respectively. For the estimation of the fruit firmness, they were 0.89 and 0.035. This study demonstrated feasibility of information which is derived from vibration response curves for predicting fruit ripeness. The vibration response of watermelon using the LDV method is measured without direct contact of the device with watermelon; it is accurate and timely, which could result in significant advantage for the commercial-scale classifying of watermelons based on consumer demands.

Fuzzy-Rule-Based faults classification of gearbox tractor

This paper presents a fault Classification method based on a fuzzy inference system. The vibratio... more This paper presents a fault Classification method based on a fuzzy inference system. The vibration signal from a piezoelectric transducer is captured for the following conditions of MF 285 gearbox: 'Healthy Gearbox' (H), 'Gear with tooth face worn' (W) and 'Gear with tooth face broken' (B), at three working speed (700, 1500 and 1800 rpm). The features of signal were extracted using descriptive statistic parameters. The output of the J48 algorithm is a decision tree that was employed to produce the crisp if-then rule and membership function sets. Results showed that the total classification accuracy for 700, 1500 and 1800 rpm conditions were about 79.63%, 100% and 96.3%.

Investigation of Effective Factors on Runoff Generation and Sediment Yield of Loess Deposits Using Rainfall Simulator

Soil Erosion Studies, 2011

Despite of many studies which have been performed on loesses, a comprehensive and acceptable, int... more Despite of many studies which have been performed on loesses, a comprehensive and acceptable, international definition of loesses does not exist yet which can be due to complex formation, physical characteristics and diversity of loesses on the surface of the earth. Therefore, many researchers express loess according to their own objective and subjective. Loess and loess-like deposits cover about %10 of the earth surface. The main areas covered by loesses are: China, Central Asia, east and central Europe, parts of North America, Argentina and New Zealand (Rozoycki, 1991). One of the effective sedimentary processes in Quaternary of Iran is combined glacialaeolian processes which formed loess deposits. Loess deposits of Golestan Province have the area of more than 320000 ha, of which 220000 ha are located in Gorganrood Catchment (Khaje, 2003). By researching paleosoles of Iran, Kehl et al. (2005) proposed that the formation of paleosoles formed in interglacial and more arid periods after interglacial phases of Quaternary period. According to the definition, typical loess or real loess is a porous, non-layering, yellow and homogenous sediment which has undergone a little diagenesis and its particles are mostly coarse-grain silt. Different perspectives have caused naming loess different terms such as rock, sediment, formation or soil. Loesses which have been transported and deposited in a new place by different processes, mainly water, have been called "Reworked Loess". Some of the most typical differences of these loesses with true loesses are that reworked loesses are heterogeneous and layered. Usually these deposits have undergone erosion and sedimentation phases and fine to coarse gravels may also be found in them. Paleosoles which are present as interlayes in some loesses are red horizons which have been formed due to climatic changes in Quaternary and formation of warm and humid climatic conditions. Mineralogical composition of most of loesses includes: Quartz, Feldspar, Calcite, Dolomite, Mica and Clay minerals. Due to chemical weathering of ferroginous minerals and formation of iron oxide and hydroxide, the color of loesses is usually yellow and rarely brown (Okhravi and Amini, 2001). They usually form highly sloped even vertical walls. Due to the fact that particles of loesses are angular, their porosity is high, but due to the abundance of silt particles, low permeability and absence of cement between the particles, they are usually erodible and produce high amount of runoff. Loessic deposits of the studied area are usually relatively resistant in arid conditions but in contact with water, they are highly unstable and erodible. These deposits usually have considerable thicknesses that can be observed in roadcuts (Picture 1).

An Efficient Iris Coding Based on Gauss-Laguerre Wavelets

Lecture Notes in Computer Science

In this paper preliminary results of a new iris recognition algorithm using Gauss-Laguerre filter... more In this paper preliminary results of a new iris recognition algorithm using Gauss-Laguerre filter of circular harmonic wavelets are presented. Circular harmonic wavelets (CHWs) applied in this paper for iris pattern extraction, are polar-separable wavelets with harmonic angular shape. The main focus of this paper is on iris coding using Gauss-Laguerre CHWs which constitute a family of orthogonal functions satisfying wavelet admissibility condition required for multiresolution pyramid structure. It is shown that Gauss-Laguerre wavelets having rich frequency extraction capabilities are powerful tools for coding of iris patterns. By judicious tuning of Laguerre parameters, a 256-byte binary code is generated for each iris. A fast matching scheme based on Hamming distance is used to compute the similarity between pairs of iris codes. Preliminary experimental results on CASIA and our database indicate that the performance of the proposed method is highly accurate with zero false rate and is comparable with Daugman iris recognition algorithm well publisized in literature.

Estimation of the anesthetic depth using wavelet analysis of electroencephalogram

2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society

This paper investigates the use of wavelet decomposition of the electroencephalogram (EEG) to ass... more This paper investigates the use of wavelet decomposition of the electroencephalogram (EEG) to assess the hypnotic state of anesthetized patients undergoing surgery. A single case study and a comparison with an existing monitor of hypnosis are presented. The proposed technique can differentiate clearly between the anesthetized state and the awake "baseline" state.

Energy inputs and outputs in a chickpea production system in Kurdistan, Iran

African Crop Science Journal, 2011

Chickpea (Cicer arietinum L.) is one of the most important grain legumes which traditionally cult... more Chickpea (Cicer arietinum L.) is one of the most important grain legumes which traditionally cultivated in marginal areas and saline soils. In this study, chickpea production in Kurdistan, Iran and the energy equivalences of input used in production were investigated. The aims of this study were to determine the amount of inputoutput energy used in chickpea production, to investigate the efficiency of energy consumption, to make an economic analysis of chickpea production, and to establish a relation between energy inputs and yield. Data were collected through a survey using a face-to-face questionnaire. Diesel energy engrossed 37.9% of total energy, followed by chemical fertiliser 29.6% during production period. Energy efficiency was 1.04, and energy productivity was 0.07 kg MJ-1. The profit-cost ratio of the farms was 1.17. Calculated net return was 42.2 $ ha-1 in the investigated farms. The Cobb-Douglas function,, and the linear function, , were selected to establish the best fitness relations between the production and various energy inputs. Whereas the R squares in both models are close, but it has shown that the Cobb-Douglas model was better than linear model.

Optimization and Efficient Purification in Production of Brucella melitensis Recombinant HSP A and TF Proteins With Low Endotoxin Contents

Jundishapur Journal of Microbiology, 2013

Background: The development of an effective subunit vaccine against brucellosis is a research are... more Background: The development of an effective subunit vaccine against brucellosis is a research area of intense. But optimization of recombinant proteins production in Escherichia coli and content of endotoxins associated with final recombinant proteins are very important. Objectives: In the present study, expression and purification of Brucella melitensis rHSP and rTF were optimized to reduce endotoxin contaminants. Materials and Methods: pDEST-tf and pDEST-hsp were transformed into E. coli BL21 (DE3), and then B. melitensis recombinant HSPA and TF proteins were overexpressed. Purification of these proteins was optimized to remove most of endotoxin contaminants from the end product using 0.1% Triton X-114 in washing buffers. Results: An endotoxin reduction of less than 0.05 EUmg/1 was achieved with protein recovery close to an 80% yield. Conclusions: As this new protocol requires only one step to simultaneously purify tagged proteins and eliminate endotoxins, it represents a substantial advantage in time, effort, and expense.

Determination of Optimum Life (Economic Life) for Mf285 Tractor: A Case Study in Center Region of Iran

American-Eurasian J. Agric. …, 2008

Abstract: Making use of tractor to do agricultural mechanized operations is responsible for a fun... more

A practical approach to electromotor fault diagnosis of Imam Khomaynei silo by vibration condition monitoring

African Journal of Agricultural Research, Apr 30, 2009

Practical experience has shown that vibration technique in a machine condition monitoring program... more Practical experience has shown that vibration technique in a machine condition monitoring program provides useful reliable information, bringing significant cost benefits to industry. The objective of this research was to investigate the correlation between vibration analysis and electromotor fault diagnosis. This was achieved by vibration analysis of an electromotor in Imam Khomaynei silo. The vibration analysis was initially run under regular interval during machine life. A series of tests were then conducted under the operating hours of electromotor. Vibration data was regularly collected. Overall vibration data produced by vibration analysis was compared with previous data. Numerical data produced by vibration analysis were compared with vibration spectra in standard condition of healthy electromotor, in order to quantify the effectiveness of the vibration condition monitoring technique. The results of this paper have given more understanding on the dependent roles of vibration analysis in predicting and diagnosing of electromotor faults.

Prediction Of Watermelon Consumer Acceptability Based On Vibration Response Spectrum

It is difficult to judge ripeness by outward characteristics such as size or external color. In t... more It is difficult to judge ripeness by outward characteristics such as size or external color. In this paper a nondestructive method was studied to determine watermelon (Crimson Sweet) quality. Responses of samples to excitation vibrations were detected using laser Doppler vibrometry (LDV) technology. Phase shift between input and output vibrations were extracted overall frequency range. First and second were derived using frequency response spectrums. After nondestructive tests, watermelons were sensory evaluated. So the samples were graded in a range of ripeness based on overall acceptability (total desired traits consumers). Regression models were developed to predict quality using obtained results and sample mass. The determination coefficients of the calibration and cross validation models were 0.89 and 0.71 respectively. This study demonstrated feasibility of information which is derived vibration response curves for predicting fruit quality. The vibration response of watermelon...

Surveying and Comparing Thermal Conductivity and Physical Properties of Oil Base Nanofluids Containing Carbon and Metal Oxide Nanotubes

Journal of Nanostructures, 2012

In this research, nano materials with tubular structures are added to SAE 20W50 engine oil to stu... more In this research, nano materials with tubular structures are added to SAE 20W50 engine oil to study the rate of their effects on the properties of engine oil. Multi-walled carbon nanotubes (MWCNTs) and vanadium oxide nanotubes (VONTs) has been used as two different additive materials, one of them is carbonic and the other is metallic oxides and their effect on different parameters containing viscosity, thermal conductivity coefficient, flash point and pour point of engine oil as the quality properties of engine oil has been studied and compared. The samples of two concentrations 0.1 and 0.2 wt% with using planetary ball mill were made. The obtained results show that MWCNTs in all cases, which have been evaluated, had better functionality with respect to vanadium oxide nanotubes. In the 0.1 wt% concentration, flash point of MWCNTs/oil and VONTs/oil increased about 9.3% and 5.8% respectively. In addition, thermal conductivity of them increased 13.2% and 10.2% respectively.

Experimental Research on Variation of Pore Water Pressure in Constant Rate of Strain Consolidation Test

Acta Geotechnica Slovenica, 2014

Constant rate of strain (CRS) consolidation is a rapid test method which is used for determinatio... more Constant rate of strain (CRS) consolidation is a rapid test method which is used for determination of compressibility of clayey soils. In a CRS test, the appropriate strain rate is selected based on pore water pressure ratio, i.e. the ratio of pore pressure to total stress. In the present study, to investigate the effect of strain rate on variation of pore water pressure ratio, four different clay samples of different plasticity were tested by CRS apparatus. The results of the experiments showed that the trend of variation of pore water pressure is dependent on the drained water flow regime which may be either Darcy or non-Darcy. The results also indicated that the plasticity of clay does not have considerable effect on variation of pore water pressure.

An Appropriate Approach for Misalignment Fault Diagnosis Based on Feature Selection and Least Square Support Vector Machine

A study is presented to diagnosis of misalignment fault using feature extraction and selection te... more A study is presented to diagnosis of misalignment fault using feature extraction and selection technique and support vector machine (SVM) classifier. The time-domain vibration signals of a compressor with normal and misalignment conditions in driven end (DE) are gained for feature extraction. The features are extracted by using the statistical and vibration parameters. Then stepwise backward selection is applied for selecting the significant features. The selected features are used as inputs to the classifier for two-class (normal or misalignment) identification. The roles of stepwise backward selection technique and SVM classifier are investigated. The results indicate the potential of the proposed intelligent method in misalignment fault diagnosis of the compressor.

Runoff and sediment yield modeling using WEPP in a semi-arid environment (Case study: Orazan Watershed)

Desert, 2011

Water erosion is a major environmental problem in many parts of the world. Majority of semi-arid ... more Water erosion is a major environmental problem in many parts of the world. Majority of semi-arid countries are concerned because of their specific climate and soils sensitivity, but also because of the recent intensification of human activities and agricultural practices. Accurate estimation of water erosion for various land-use and climate scenarios is so an important key to define sustainable management policies. In the last decades, several studies have been carried out to build models suitable for quantifying sedimentation. Among these models, the Water Erosion Prediction Project (WEPP), is a physically based, distributed-parameter model that has been developed and mainly validated in America. Only few studies have investigated its applicability to environmental conditions that differs from those where the model was developed. The aim of this work is to test the efficiency of WEPP model to predict runoff and sediment yield at catchment scale in a semi-arid area. Continuous simul...

Some Physical and Mechanical Properties of Iranian Wild Pistachio (Pistachio mutica L.)

Wild pistachio is oiling crop; therefore, physical and engineering properties are necessitate to ... more Wild pistachio is oiling crop; therefore, physical and engineering properties are necessitate to determine for processing and equipment design. In this study, some raw material characteristics were determined for Iranian wild pistachio (Pistachio Mutica L.), in order to collect information about identifying some physical and mechanical properties of them. The average grain length, width and thickness were 7.62, 8.84 and 6.42 mm, respectively. The geometric mean diameter, thousand grain kernel and aspect ratio were 7.86 mm, 302.28g and 1.17, respectively. True density, bulk density and porosity were 1.07 kg m , 0.5 kg m and 0.5%, 3 3 respectively while the static coefficient of friction varied from 0.44 on plywood surface to 0.56 on galvanized iron. The angle of repose for static and emptying were 52.5 and 28.86 degree, respectively. Whereas the failure force, elongation and energy were 143.07 N, 1.68 mm and 201.29 kPa respectively.

Development of a New Threshold Based Classification Model for Analyzing Thermal Imaging Data to Detect Fungal Infection of Pistachio Kernel

Agricultural Research, 2013

Thermal images have beneficial information which can be used for diagnostic purposes. The informa... more Thermal images have beneficial information which can be used for diagnostic purposes. The information can be released by applying appropriate analyses methods. In this research, a new algorithm, threshold based classification (TBC), was developed to analyze thermal images of healthy and fungal-infected pistachio kernels in MATLAB 2010 A environment. Results showed that TBC algorithm can classify successfully healthy and infected pistachio kernels without considering the infection stages.

An Assessment of Specific Sediment Yield of Geological Formations Using Investigated Sedimentary Deposits in Reservoirs and Fingerprinting

Journal of Agricultural Science and Technology

Sediment yield data, collected for most regions in Iran has been insufficient and not so reliable... more Sediment yield data, collected for most regions in Iran has been insufficient and not so reliable and there is still not any sufficiently reliable methodology available for sediment yield assessment in the country as a whole. On the other hand, an attainment of reliable sediment yield data is a must and key requirement for the design of effective sediment management as well as control strategies. Sediment deposition in reservoirs is assumed as a very useful tool in providing such data. The main objective of the present research was to discuss a combination of both source fingerprinting technique and reservoir sediment survey to provide reliable data on sediment yield of geological formations for three small catchments in Semnan Province, Iran. Throughout the study, the volume and mass of deposited sediments in reservoirs were initially assessed. Fingerprinting technique was employed to identify the contribution to, as well as the specific sediment deposition yield of each geological...

Application of Remote Sensing in the Agricultural Land-Use Assessment

The calculation of Normalized Difference Vegetation Indices (NDVI) can be very useful in the gene... more The calculation of Normalized Difference Vegetation Indices (NDVI) can be very useful in the generation of a land-use/land-cover classification. Calculation of a vegetative index (VI) from remotely sensed data can be used to quantify the amount of vegetation on the Earth's land surface. Numerous VI's exist, however the most commonly used VI is the NDVI. To detect the land-use and land-cover, the long term monitoring by the satellite images is useful as a big heritage. In this paper, the land-use assessment was investigated by using of the satellite images. After processing and exploitation of the data, the relation between bands was estimation and NDVI index were calculated. Then NDVI index with ground-related information was compared. Results showed that satellite images could detect the land-use changes in the local scale and vegetation index was suitable to estimate the land-use classification.

Determining the reliability function of farm tractors

There is an optimum time for implementing field operation of various crops in each region. If the... more There is an optimum time for implementing field operation of various crops in each region. If the operation is accomplished sooner or later, it will cause a reduction in yield quantity and quality. The cost of this reduction is named "timeliness cost". Annual timeliness cost is estimated by an equation reported in ASAE standards. MF285 tractors have low reliability in Iran. Generally, low tractor reliability has an uncertainty in implementation of farm operation which it is not considered in ASAE equation for calculating of timelines cost. This uncertainty causes a cost being a part of timeliness cost and is produced due to tractor failure within farm operation. The purpose of this study was to determine the reliability function of MF285 tractors operated in Debal Khazaei Agro-Industry Co. in Khuzestan province of Iran. Thus, in this study a function-fit model for reliability of farm tractors was determined. Afterwards, tractors working times to a failure (hours) in tenth year of tractor life were fitted with normal, exponential, lognormal, poisson and weibull age distribution functions using moment estimation. Depending on Chi square test, the best reliability function for this given situation was exponential distribution function with λ = 0.025.

Energy use and economic analysis of strawberry production in Sanandaj zone of Iran

The aim of this study was to determine the energy consumption and economic analysis for strawberr... more The aim of this study was to determine the energy consumption and economic analysis for strawberry production. The data were collected from 60 farmers growing strawberry in the Sanandaj zone of Iran by using a face-to-face questionnaire in August-September 2009. The plowing operation at the study area was done by two methods; manually plow (P 1) and machinery plow (P 2). Also the irrigation operation was done by two methods; pumping irrigation (P) and non pumping irrigation (NP). Univariate analysis of variance was used for finding the differences among the total energy used for production and profitability of this crop in the different methods at the 5% and 1% level. Total energy used in various farm operations during strawberry production was 53,605 MJ. ha-1. Total energy output was 17,338 MJ. ha-1 , and the average annual yield of strawberry farms was 9,125 kg. ha-1. Energy efficiency was 0.32, and energy productivity calculated as 0.17 kg. MJ-1. This means a production of 0.17 kg per unit energy. The difference between total input energy in the different irrigation types (NP and P) is significant at 1% level. There is not any significant difference between different plow types at the 5% level. The interaction of irrigation types and plow types is significant at 5% level. The profit-cost ratio, productivity, and net profit in the strawberry production are 1.2, 0.99, and 1,825 $. ha-1 , respectively. The difference between net return in the different irrigation types (NP and P) is significant at 5% level. The difference between net return in the different plow types (P 1 and P 2) is significant at 1% level.

Application of Vibration Response for the Nondestructive Ripeness Evaluation of Watermelons

The assessment of watermelon ripeness on the basis of its apparent properties, such as size or sk... more The assessment of watermelon ripeness on the basis of its apparent properties, such as size or skin colour, is very difficult as traditional methods have various problems and limitations. These include lack of uniformity, concentration of excitation energy within narrow bands and need for physical contact between a fruit and the measuring device. In this study a new method making use of Laser Doppler Vibrometry technology (LDV) has been applied to evaluate the ripeness of watermelons, without many of those limitations. At first a watermelon is excited by a shaker as vibration generating device within a range of frequencies. At the same time, the vibrating response of the upper side of the fruit is measured by LDV. The device emits a laser beam on a spot above the sample. The beam reflected from that point is received by the LDV and finally the vibration response of the sample is measured and the signal is sent to the computer. Using a fast fourier transform algorithm and the ratio of input to response signals, the frequency response of the fruit sample was processed and the desired results extracted. After the nondestructive tests were completed, the watermelon ripeness was evaluated by means of a destructive method. The sugar and firmness of the samples were measured as ripeness indices. In this study four modal properties were derived and used for developing predictive models to relate the vibration response results with the watermelon sugar and firmness. Interaction models by including the fruit mass were found more accurate than other common multiple models. The nonlinear regression model has five variables as sample mass, first and second resonant frequency and also damping ratios of them. For this model the coefficients of determination and the mean square error for the estimation of the fruit sugar were 0.9 and 0.79 respectively. For the estimation of the fruit firmness, they were 0.89 and 0.035. This study demonstrated feasibility of information which is derived from vibration response curves for predicting fruit ripeness. The vibration response of watermelon using the LDV method is measured without direct contact of the device with watermelon; it is accurate and timely, which could result in significant advantage for the commercial-scale classifying of watermelons based on consumer demands.

Fuzzy-Rule-Based faults classification of gearbox tractor

This paper presents a fault Classification method based on a fuzzy inference system. The vibratio... more This paper presents a fault Classification method based on a fuzzy inference system. The vibration signal from a piezoelectric transducer is captured for the following conditions of MF 285 gearbox: 'Healthy Gearbox' (H), 'Gear with tooth face worn' (W) and 'Gear with tooth face broken' (B), at three working speed (700, 1500 and 1800 rpm). The features of signal were extracted using descriptive statistic parameters. The output of the J48 algorithm is a decision tree that was employed to produce the crisp if-then rule and membership function sets. Results showed that the total classification accuracy for 700, 1500 and 1800 rpm conditions were about 79.63%, 100% and 96.3%.

Investigation of Effective Factors on Runoff Generation and Sediment Yield of Loess Deposits Using Rainfall Simulator

Soil Erosion Studies, 2011

Despite of many studies which have been performed on loesses, a comprehensive and acceptable, int... more Despite of many studies which have been performed on loesses, a comprehensive and acceptable, international definition of loesses does not exist yet which can be due to complex formation, physical characteristics and diversity of loesses on the surface of the earth. Therefore, many researchers express loess according to their own objective and subjective. Loess and loess-like deposits cover about %10 of the earth surface. The main areas covered by loesses are: China, Central Asia, east and central Europe, parts of North America, Argentina and New Zealand (Rozoycki, 1991). One of the effective sedimentary processes in Quaternary of Iran is combined glacialaeolian processes which formed loess deposits. Loess deposits of Golestan Province have the area of more than 320000 ha, of which 220000 ha are located in Gorganrood Catchment (Khaje, 2003). By researching paleosoles of Iran, Kehl et al. (2005) proposed that the formation of paleosoles formed in interglacial and more arid periods after interglacial phases of Quaternary period. According to the definition, typical loess or real loess is a porous, non-layering, yellow and homogenous sediment which has undergone a little diagenesis and its particles are mostly coarse-grain silt. Different perspectives have caused naming loess different terms such as rock, sediment, formation or soil. Loesses which have been transported and deposited in a new place by different processes, mainly water, have been called "Reworked Loess". Some of the most typical differences of these loesses with true loesses are that reworked loesses are heterogeneous and layered. Usually these deposits have undergone erosion and sedimentation phases and fine to coarse gravels may also be found in them. Paleosoles which are present as interlayes in some loesses are red horizons which have been formed due to climatic changes in Quaternary and formation of warm and humid climatic conditions. Mineralogical composition of most of loesses includes: Quartz, Feldspar, Calcite, Dolomite, Mica and Clay minerals. Due to chemical weathering of ferroginous minerals and formation of iron oxide and hydroxide, the color of loesses is usually yellow and rarely brown (Okhravi and Amini, 2001). They usually form highly sloped even vertical walls. Due to the fact that particles of loesses are angular, their porosity is high, but due to the abundance of silt particles, low permeability and absence of cement between the particles, they are usually erodible and produce high amount of runoff. Loessic deposits of the studied area are usually relatively resistant in arid conditions but in contact with water, they are highly unstable and erodible. These deposits usually have considerable thicknesses that can be observed in roadcuts (Picture 1).

An Efficient Iris Coding Based on Gauss-Laguerre Wavelets

Lecture Notes in Computer Science

In this paper preliminary results of a new iris recognition algorithm using Gauss-Laguerre filter... more In this paper preliminary results of a new iris recognition algorithm using Gauss-Laguerre filter of circular harmonic wavelets are presented. Circular harmonic wavelets (CHWs) applied in this paper for iris pattern extraction, are polar-separable wavelets with harmonic angular shape. The main focus of this paper is on iris coding using Gauss-Laguerre CHWs which constitute a family of orthogonal functions satisfying wavelet admissibility condition required for multiresolution pyramid structure. It is shown that Gauss-Laguerre wavelets having rich frequency extraction capabilities are powerful tools for coding of iris patterns. By judicious tuning of Laguerre parameters, a 256-byte binary code is generated for each iris. A fast matching scheme based on Hamming distance is used to compute the similarity between pairs of iris codes. Preliminary experimental results on CASIA and our database indicate that the performance of the proposed method is highly accurate with zero false rate and is comparable with Daugman iris recognition algorithm well publisized in literature.

Estimation of the anesthetic depth using wavelet analysis of electroencephalogram

2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society

This paper investigates the use of wavelet decomposition of the electroencephalogram (EEG) to ass... more This paper investigates the use of wavelet decomposition of the electroencephalogram (EEG) to assess the hypnotic state of anesthetized patients undergoing surgery. A single case study and a comparison with an existing monitor of hypnosis are presented. The proposed technique can differentiate clearly between the anesthetized state and the awake "baseline" state.

Energy inputs and outputs in a chickpea production system in Kurdistan, Iran

African Crop Science Journal, 2011

Chickpea (Cicer arietinum L.) is one of the most important grain legumes which traditionally cult... more Chickpea (Cicer arietinum L.) is one of the most important grain legumes which traditionally cultivated in marginal areas and saline soils. In this study, chickpea production in Kurdistan, Iran and the energy equivalences of input used in production were investigated. The aims of this study were to determine the amount of inputoutput energy used in chickpea production, to investigate the efficiency of energy consumption, to make an economic analysis of chickpea production, and to establish a relation between energy inputs and yield. Data were collected through a survey using a face-to-face questionnaire. Diesel energy engrossed 37.9% of total energy, followed by chemical fertiliser 29.6% during production period. Energy efficiency was 1.04, and energy productivity was 0.07 kg MJ-1. The profit-cost ratio of the farms was 1.17. Calculated net return was 42.2 $ ha-1 in the investigated farms. The Cobb-Douglas function,, and the linear function, , were selected to establish the best fitness relations between the production and various energy inputs. Whereas the R squares in both models are close, but it has shown that the Cobb-Douglas model was better than linear model.

Optimization and Efficient Purification in Production of Brucella melitensis Recombinant HSP A and TF Proteins With Low Endotoxin Contents

Jundishapur Journal of Microbiology, 2013

Background: The development of an effective subunit vaccine against brucellosis is a research are... more Background: The development of an effective subunit vaccine against brucellosis is a research area of intense. But optimization of recombinant proteins production in Escherichia coli and content of endotoxins associated with final recombinant proteins are very important. Objectives: In the present study, expression and purification of Brucella melitensis rHSP and rTF were optimized to reduce endotoxin contaminants. Materials and Methods: pDEST-tf and pDEST-hsp were transformed into E. coli BL21 (DE3), and then B. melitensis recombinant HSPA and TF proteins were overexpressed. Purification of these proteins was optimized to remove most of endotoxin contaminants from the end product using 0.1% Triton X-114 in washing buffers. Results: An endotoxin reduction of less than 0.05 EUmg/1 was achieved with protein recovery close to an 80% yield. Conclusions: As this new protocol requires only one step to simultaneously purify tagged proteins and eliminate endotoxins, it represents a substantial advantage in time, effort, and expense.

Determination of Optimum Life (Economic Life) for Mf285 Tractor: A Case Study in Center Region of Iran

American-Eurasian J. Agric. …, 2008

Abstract: Making use of tractor to do agricultural mechanized operations is responsible for a fun... more