Mahmoud younis - Academia.edu (original) (raw)

Papers by Mahmoud younis

Horticulturae

Fresh dates of the Barhi cultivar at the Khalal maturity stage are well known for their pleasant ... more Fresh dates of the Barhi cultivar at the Khalal maturity stage are well known for their pleasant taste, crispy texture, and bright yellow color. One of the primary technical challenges is preserving the initial high-quality fresh Khalal Barhi dates and extending their shelf life for the longest possible period after harvesting and during the marketing process. Resolving this problem would permit the export of high-quality fresh Saudi dates to international markets. Therefore, the main aim of this study is to evaluate the feasibility of utilizing a pulsed electric field as a novel non-thermal postharvest processing technology for preserving the nutritional, microbiological, and physical quality of Barhi dates during storage at different temperatures and durations. To accomplish this goal, a five-factor mixed-level central composite rotating design (CCRD) with a response surface methodology (RSM) model was used to define the best PEF processing conditions and subsequent storage enviro...

Horticulturae

Barhi dates are widely consumed at Khalal maturity stage and preserving the freshness quality of ... more Barhi dates are widely consumed at Khalal maturity stage and preserving the freshness quality of Barhi at this stage is a challenging task as this period is short and the fruits are more perishable. In this study, response surface methodology (RSM) was applied to optimize the infrared (IR) treatment and storage conditions for preserving the physicochemical, microbial, and bioactive attributes of fresh Barhi dates. The effect of four factors, IR temperature (50, 70, 90, and 110 °C), IR time (1, 2, 3, and 4 min), storage temperature (1, 5, 15, and 25 °C), and storage time (1, 6, 11, 16, and 21 days), on the responses of total soluble solids (TSS), hardness, total color change (ΔE), total viable count (TVC), total phenolic content (TPC), antioxidant activity (DPPH), and glucose content were evaluated following central composite design (CCD). IR temperature, IR time, storage temperature, and storage time significantly affected the physical, microbial, and bioactive attributes of Barhi d...

International Journal of Agricultural and Biological Engineering, 2020

Barhi is a high-quality date cultivar, typically harvested and consumed fresh at the Khalal matur... more Barhi is a high-quality date cultivar, typically harvested and consumed fresh at the Khalal maturity stage when the fruits are crispy and sweet with bright yellow color. The shelf-life of the Khalal stage (2-3 weeks) is very short for effective marketing. This study aimed at investigating the role of calcium chloride (CaCl 2) and salicylic acid (SA) as pre-storage treatments in preserving the color and texture of the fruit during both cold and controlled atmosphere (CA) storage systems. Fresh-harvested Barhi fruits at the Khalal stage were treated with CaCl 2 (2%) or SA (2.0 mM), and then stored in cold and CA systems. The weight loss and decay percentages in the treated samples decreased, whereas the total soluble solids of the treated samples increased compared with those of the untreated ones. The best treatment in limiting changes in the color and texture of the fruits was CaCl 2 treatment during CA storage.

Journal of food science and technology, 2018

The effects of modified atmosphere packaging (MAP) on various physicochemical quality attributes ... more The effects of modified atmosphere packaging (MAP) on various physicochemical quality attributes of fresh Barhi dates at the Khalal (yellow) stage were studied. Polypropylene (PP) and polyethylene (PE) plastic with varied perforation sizes (0, 50, 100 and 150 µm) were evaluated for storage of date fruits at temperatures of 1, 5, 15 and 25 °C up to 45 days. MAP showed significant effects on fruit quality. PP date packages perforated with 150-µm perforations and stored at 5 °C had the lowest acidity and microbial load. Dates packed in PE exhibited higher pectin methylesterase (PME) and polyphenol oxidase (PPO) activities than dates packed in PP. Dates stored in nonperforated packages had the highest PME, PPO and invertase activities. The maximum fructose and glucose contents were observed in PP-packaged dates stored at 15 °C. Analysis of the interactions of several MAP variables revealed temperature as the major variable controlling the quality of dates. The findings showed that MAP c...

Pakistan Journal of Agricultural Sciences, 2016

Fresh date fruits (Barhi cultivar) at Khalal stage of maturity were frozen by two different metho... more Fresh date fruits (Barhi cultivar) at Khalal stage of maturity were frozen by two different methods; individual quick freezing (IQF), and conventional slow freezing (CSF). The frozen dates were stored for 9 months at-20°C and-40°C, through conventional and individual quick freezing methods, respectively. Texture profile analysis parameters (hardness, elasticity, chewiness and resilience), color, and nutrition (enzymes and sugars) properties for fresh and frozen dates were measured after every three months of frozen storage. IQF technique showed better result in quality maintaining of fresh date fruits than CSF. Color and textural parameters of the frozen dates were affected by the freezing method and the frozen storage period. IQF method is superior in preserving the fresh Barhi fruits color values, textural parameters and nutritional aspects compared to CSF method.

Saudi Journal of Biological Sciences, 2016

Fresh harvested dates are perishable and there is a need for extending their shelf life while pre... more Fresh harvested dates are perishable and there is a need for extending their shelf life while preserving their fresh like quality characteristics. This study evaluates three different freezing methods, namely cryogenic freezing (CF) using liquid nitrogen; individual quick freezing (IQF) and conventional slow freezing (CSF) in preserving the quality and stability of dates during frozen storage. Fresh dates were frozen utilizing the three methods. The produced frozen dates were frozen stored for nine months. The color values, textural parameters, and nutrition qualities were measured for fresh dates before freezing and for the frozen dates every three months during the frozen storage. The frozen dates' color values were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing followed by individual quick freezing compared to the conventional slow freezing. The results revealed large disparity among the times of freezing of the three methods. The freezing time accounted to 10 min for CF, and around 80 min for IQF, and 1800 min for CSF method.

Journal of the Saudi Society of Agricultural Sciences, 2015

Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal matur... more Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage). These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi) at Khalal maturity stage. Fresh date fruits (cv. Barhi) at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at À20°C and À40°C for the conventional and cryogenic freezing, respectively). Color values, textural properties (hardness, elasticity, chewiness and resilience), and nutrition attributes (enzymes and sugars) for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system.

Plants

The Barhi date is a high-quality date cultivar whose fruits (dates) are plucked and eaten fresh w... more The Barhi date is a high-quality date cultivar whose fruits (dates) are plucked and eaten fresh when they reach the Khalal maturity stage due to their sweetness, crispiness, and yellow skin color. After harvesting, Khalal Barhi fruits rapidly matured to the Rutab stage, where their tissues become soft and their skin color browner. This results in a decrease in their market value and customer demand. This study aims at investigating the effectiveness of the postharvest ultrasonic treatment in conserving the physical, microbial, and nutritional quality of Barhi fruits and extending their shelf life. To achieve the goals of the present work, the response surface methodology (RSM) was used for the optimization of the ultrasonic intensity (50, 100, 150, and 200 W/cm2) and application time (5, 10, 15, and 20 min) to preserve the Barhi dates high quality features for varied storage temperatures (1, 5, 15, and 25 °C) and duration (1, 6, 16, and 21 days). In RSM, a four-factors-mixed-levels ...

IEEE Symposium on Industrial Electronics & Applications, 2010

This paper presents a grid connected system. Three phase DC-AC inverters used to convert the regu... more This paper presents a grid connected system. Three phase DC-AC inverters used to convert the regulated DC power to AC power suitable for grid connection. Third harmonic injection PWM (THIPWM) was employed to reduce the total harmonic distortion and for maximum use of the voltage source. DSP was used to generate the accurate THIPWM for grid connection, by synchronizing the inverter voltage with the grid voltage. The application of THIPWM to parallel connected inverter reduces the total harmonic distortion and increases efficiency of the inverter. Experimental results validate the developed model and the proposed system.

Power and Energy, IEEE International Conference on, 2006

Abstract This paper presents a fuel cell model supplying three-phase DC/AC inverter. Simulink use... more Abstract This paper presents a fuel cell model supplying three-phase DC/AC inverter. Simulink used as interactive tool to model the proposed fuel cell system. The fuel cell output voltage is proportional to the change of the air (oxidant) pressure, the hydrogen (fuel) pressure and the current withdrawn from the fuel cell. Three-phase DC/AC inverter used to supply the AC load. Symmetric space vector pulse width modulation used to drive the three-phase inverter so that minimum harmonic distortion on the load side voltage and current ...

IEEE Conference on Industrial Electronics and Applications, 2009

This paper presents the design and analysis of a new configuration of parallel connected inverter... more This paper presents the design and analysis of a new configuration of parallel connected inverter suitable for distributed generation application. The configuration consists of DC/DC converter and parallel three-phase DC/AC inverter. Series resistors added to the inverter output to maintain same current in each inverter of the two parallel inverters, and to reduce the circulating current in the parallel inverters to the minimum. Third harmonic injection PWM (THIPWM) reduces the total harmonic distortion and to make maximum use of the voltage source. DSP was used to generate the THIPWM and the control algorithm for the converter. PID controller is applied on the full-bridge DC/DC converter side to maintain the AC voltage to the required level. Selected experimental results have been shown to validate the proposed system.

Journal of Applied Sciences, 2009

ABSTRACT

IEEE GCC Conference & Exhibition, 2011

This paper presents a new technique for accurate fault location based on voltage measurement from... more This paper presents a new technique for accurate fault location based on voltage measurement from one end of the two-terminal transmission line and Smooth Support Vector Machine (SSVM). Due to common problems of current transformer during fault location and as a result increasing the cost and reduction of the accuracy, proposed technique is independent of current measurement and based on one terminal voltage measurement of the transmission line. Post-fault voltage at one end of the line is measured and used in calculation of the fault location. GPS (global positioning system) is not required for this technique resulting in a reduction of economic cost. Using the proposed technique, fault location can be estimated with a lower than 0.025% error without using current transformers and GPS. EMTP/ATP simulation and SSVM results show that the proposed fault location technique is independent of fault type, fault resistance and fault inception of the transmission line.

Power and Energy, IEEE International Conference on, 2010

This paper presents a new technique for accurate fault locator based on synchronized voltage meas... more This paper presents a new technique for accurate fault locator based on synchronized voltage measurement and smooth support vector machines (SSVM) HV teed feeder transmission line. The approach consists of detection of faulted branch, classification of fault type and determination of exact fault location. Post-fault measured voltages waveforms are collected from only two ends of the three branches teed feeder

Problem statement: Most Nickel based Hastelloy C-276 is a difficult-to-machine material because o... more Problem statement: Most Nickel based Hastelloy C-276 is a difficult-to-machine material because of its low thermal diffusive property and high strength at high temperature. Machinability consideration of nickel based Hastelloy C-276 in turning operations has been carried out using ceramic inserts under dry conditions. Approach: This study described a modification approach applied to a fuzzy logic based model for predicting cutting force where the machining parameters for cutting speed ranges, feed rate, depth of cut and approach angle are not overlapping. For this study, data were selected depending on the design of experiments. Response surface methodology was applied to predict the cutting force and to examine the fuzzy logic based model. Results: The modification approach fuzzy logic based model produced the cutting force data providing good correlation with response surface data. In this situation the cutting force data were superimposed and results were adjusted according to their own ranges. Conclusion: A review of literatures on optimization techniques revealed that there were, in particular, successful industrial applications of design of experiment-based approaches for optimal settings of process variables.

We investigate the behavior of a uniform cantilever beam with a small mass at its tip. The beam c... more We investigate the behavior of a uniform cantilever beam with a small mass at its tip. The beam can move out of a rigid body; thus, its span varies with time. The body can have no motion or can be spinning; both simulations are considered. The reasons for such investigations are: (1) it is the subject of current interest in connection with the recent developments in the space and robotics fields; and (2) to study the behavior analytically because very few analytical solutions are available. The interest here is in the linear vibratory motions of the beam with the objective of developing approximate asymptotic expressions for the beam displacements. A formulation of the problem is made which accounts for the time mass. Two ways to eject the beam out of the system are considered: root force ejection and time dependent acceleration field ejection. The assumed modes method is adopted to derive the corresponding modal equations that describe the in-plane lateral deflections of the beam. The case when there is no tip mass is also included. Approximate asymptotic expressions for the beam displacement are presented for three types of length variations: uniform, exponential, and a linear variation of the square of the length. In the course of the analysis, the system is allowed to spin about an axis normal to the ejection direction, and modal equations governing vibrations in and out of the plane of rotation are derived. Approximate expressions for the beam displacement are presented in the absence of the tip mass for the three length variations mentioned previously. An approximate solution for the beam loaded by a tip mass is presented only for uniform length variations. The results from the investigation are discussed.

International Journal of Electrical Power & Energy Systems, 2014

and sharing with colleagues.

2013 IEEE Conference on Clean Energy and Technology (CEAT), 2013

ABSTRACT Renewable energy sources This paper presents a comparison between five different cities ... more ABSTRACT Renewable energy sources This paper presents a comparison between five different cities in term of wind and solar energy potentials. It first describes the Weibull distribution functions and then analyzes the data collected from the Malaysian Meteorological Department. It then shows the average wind speed and the operation probability of a wind turbine with a cut in speed of 2.5m/s over the five chosen cities. Power density at the wind turbine's hub height is calculated with the annual operating hours of the turbine. Second, this paper compares the power output of a certain PV module in these five different cities. The implication of this study is that it gives an overall review on the wind and solar energy potentials in Malaysia and its results are significant for feasibility and optimization studies. The data obtained from the Malaysian Meteorological Department are on a daily basis from 2011 to 2012.

2011 IEEE GCC Conference and Exhibition (GCC), 2011

This paper presents a new technique for accurate fault location based on voltage measurement from... more This paper presents a new technique for accurate fault location based on voltage measurement from one end of the two-terminal transmission line and Smooth Support Vector Machine (SSVM). Due to common problems of current transformer during fault location and as a result increasing the cost and reduction of the accuracy, proposed technique is independent of current measurement and based on one terminal voltage measurement of the transmission line. Post-fault voltage at one end of the line is measured and used in calculation of the fault location. GPS (global positioning system) is not required for this technique resulting in a reduction of economic cost. Using the proposed technique, fault location can be estimated with a lower than 0.025% error without using current transformers and GPS. EMTP/ATP simulation and SSVM results show that the proposed fault location technique is independent of fault type, fault resistance and fault inception of the transmission line.

2010 IEEE International Conference on Power and Energy, 2010

This paper presents a new technique for accurate fault locator based on synchronized voltage meas... more This paper presents a new technique for accurate fault locator based on synchronized voltage measurement and smooth support vector machines (SSVM) HV teed feeder transmission line. The approach consists of detection of faulted branch, classification of fault type and determination of exact fault location. Post-fault measured voltages waveforms are collected from only two ends of the three branches teed feeder

Horticulturae

Fresh dates of the Barhi cultivar at the Khalal maturity stage are well known for their pleasant ... more Fresh dates of the Barhi cultivar at the Khalal maturity stage are well known for their pleasant taste, crispy texture, and bright yellow color. One of the primary technical challenges is preserving the initial high-quality fresh Khalal Barhi dates and extending their shelf life for the longest possible period after harvesting and during the marketing process. Resolving this problem would permit the export of high-quality fresh Saudi dates to international markets. Therefore, the main aim of this study is to evaluate the feasibility of utilizing a pulsed electric field as a novel non-thermal postharvest processing technology for preserving the nutritional, microbiological, and physical quality of Barhi dates during storage at different temperatures and durations. To accomplish this goal, a five-factor mixed-level central composite rotating design (CCRD) with a response surface methodology (RSM) model was used to define the best PEF processing conditions and subsequent storage enviro...

Horticulturae

Barhi dates are widely consumed at Khalal maturity stage and preserving the freshness quality of ... more Barhi dates are widely consumed at Khalal maturity stage and preserving the freshness quality of Barhi at this stage is a challenging task as this period is short and the fruits are more perishable. In this study, response surface methodology (RSM) was applied to optimize the infrared (IR) treatment and storage conditions for preserving the physicochemical, microbial, and bioactive attributes of fresh Barhi dates. The effect of four factors, IR temperature (50, 70, 90, and 110 °C), IR time (1, 2, 3, and 4 min), storage temperature (1, 5, 15, and 25 °C), and storage time (1, 6, 11, 16, and 21 days), on the responses of total soluble solids (TSS), hardness, total color change (ΔE), total viable count (TVC), total phenolic content (TPC), antioxidant activity (DPPH), and glucose content were evaluated following central composite design (CCD). IR temperature, IR time, storage temperature, and storage time significantly affected the physical, microbial, and bioactive attributes of Barhi d...

International Journal of Agricultural and Biological Engineering, 2020

Barhi is a high-quality date cultivar, typically harvested and consumed fresh at the Khalal matur... more Barhi is a high-quality date cultivar, typically harvested and consumed fresh at the Khalal maturity stage when the fruits are crispy and sweet with bright yellow color. The shelf-life of the Khalal stage (2-3 weeks) is very short for effective marketing. This study aimed at investigating the role of calcium chloride (CaCl 2) and salicylic acid (SA) as pre-storage treatments in preserving the color and texture of the fruit during both cold and controlled atmosphere (CA) storage systems. Fresh-harvested Barhi fruits at the Khalal stage were treated with CaCl 2 (2%) or SA (2.0 mM), and then stored in cold and CA systems. The weight loss and decay percentages in the treated samples decreased, whereas the total soluble solids of the treated samples increased compared with those of the untreated ones. The best treatment in limiting changes in the color and texture of the fruits was CaCl 2 treatment during CA storage.

Journal of food science and technology, 2018

The effects of modified atmosphere packaging (MAP) on various physicochemical quality attributes ... more The effects of modified atmosphere packaging (MAP) on various physicochemical quality attributes of fresh Barhi dates at the Khalal (yellow) stage were studied. Polypropylene (PP) and polyethylene (PE) plastic with varied perforation sizes (0, 50, 100 and 150 µm) were evaluated for storage of date fruits at temperatures of 1, 5, 15 and 25 °C up to 45 days. MAP showed significant effects on fruit quality. PP date packages perforated with 150-µm perforations and stored at 5 °C had the lowest acidity and microbial load. Dates packed in PE exhibited higher pectin methylesterase (PME) and polyphenol oxidase (PPO) activities than dates packed in PP. Dates stored in nonperforated packages had the highest PME, PPO and invertase activities. The maximum fructose and glucose contents were observed in PP-packaged dates stored at 15 °C. Analysis of the interactions of several MAP variables revealed temperature as the major variable controlling the quality of dates. The findings showed that MAP c...

Pakistan Journal of Agricultural Sciences, 2016

Fresh date fruits (Barhi cultivar) at Khalal stage of maturity were frozen by two different metho... more Fresh date fruits (Barhi cultivar) at Khalal stage of maturity were frozen by two different methods; individual quick freezing (IQF), and conventional slow freezing (CSF). The frozen dates were stored for 9 months at-20°C and-40°C, through conventional and individual quick freezing methods, respectively. Texture profile analysis parameters (hardness, elasticity, chewiness and resilience), color, and nutrition (enzymes and sugars) properties for fresh and frozen dates were measured after every three months of frozen storage. IQF technique showed better result in quality maintaining of fresh date fruits than CSF. Color and textural parameters of the frozen dates were affected by the freezing method and the frozen storage period. IQF method is superior in preserving the fresh Barhi fruits color values, textural parameters and nutritional aspects compared to CSF method.

Saudi Journal of Biological Sciences, 2016

Fresh harvested dates are perishable and there is a need for extending their shelf life while pre... more Fresh harvested dates are perishable and there is a need for extending their shelf life while preserving their fresh like quality characteristics. This study evaluates three different freezing methods, namely cryogenic freezing (CF) using liquid nitrogen; individual quick freezing (IQF) and conventional slow freezing (CSF) in preserving the quality and stability of dates during frozen storage. Fresh dates were frozen utilizing the three methods. The produced frozen dates were frozen stored for nine months. The color values, textural parameters, and nutrition qualities were measured for fresh dates before freezing and for the frozen dates every three months during the frozen storage. The frozen dates' color values were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing followed by individual quick freezing compared to the conventional slow freezing. The results revealed large disparity among the times of freezing of the three methods. The freezing time accounted to 10 min for CF, and around 80 min for IQF, and 1800 min for CSF method.

Journal of the Saudi Society of Agricultural Sciences, 2015

Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal matur... more Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage). These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi) at Khalal maturity stage. Fresh date fruits (cv. Barhi) at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at À20°C and À40°C for the conventional and cryogenic freezing, respectively). Color values, textural properties (hardness, elasticity, chewiness and resilience), and nutrition attributes (enzymes and sugars) for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system.

Plants

The Barhi date is a high-quality date cultivar whose fruits (dates) are plucked and eaten fresh w... more The Barhi date is a high-quality date cultivar whose fruits (dates) are plucked and eaten fresh when they reach the Khalal maturity stage due to their sweetness, crispiness, and yellow skin color. After harvesting, Khalal Barhi fruits rapidly matured to the Rutab stage, where their tissues become soft and their skin color browner. This results in a decrease in their market value and customer demand. This study aims at investigating the effectiveness of the postharvest ultrasonic treatment in conserving the physical, microbial, and nutritional quality of Barhi fruits and extending their shelf life. To achieve the goals of the present work, the response surface methodology (RSM) was used for the optimization of the ultrasonic intensity (50, 100, 150, and 200 W/cm2) and application time (5, 10, 15, and 20 min) to preserve the Barhi dates high quality features for varied storage temperatures (1, 5, 15, and 25 °C) and duration (1, 6, 16, and 21 days). In RSM, a four-factors-mixed-levels ...

IEEE Symposium on Industrial Electronics & Applications, 2010

This paper presents a grid connected system. Three phase DC-AC inverters used to convert the regu... more This paper presents a grid connected system. Three phase DC-AC inverters used to convert the regulated DC power to AC power suitable for grid connection. Third harmonic injection PWM (THIPWM) was employed to reduce the total harmonic distortion and for maximum use of the voltage source. DSP was used to generate the accurate THIPWM for grid connection, by synchronizing the inverter voltage with the grid voltage. The application of THIPWM to parallel connected inverter reduces the total harmonic distortion and increases efficiency of the inverter. Experimental results validate the developed model and the proposed system.

Power and Energy, IEEE International Conference on, 2006

Abstract This paper presents a fuel cell model supplying three-phase DC/AC inverter. Simulink use... more Abstract This paper presents a fuel cell model supplying three-phase DC/AC inverter. Simulink used as interactive tool to model the proposed fuel cell system. The fuel cell output voltage is proportional to the change of the air (oxidant) pressure, the hydrogen (fuel) pressure and the current withdrawn from the fuel cell. Three-phase DC/AC inverter used to supply the AC load. Symmetric space vector pulse width modulation used to drive the three-phase inverter so that minimum harmonic distortion on the load side voltage and current ...

IEEE Conference on Industrial Electronics and Applications, 2009

This paper presents the design and analysis of a new configuration of parallel connected inverter... more This paper presents the design and analysis of a new configuration of parallel connected inverter suitable for distributed generation application. The configuration consists of DC/DC converter and parallel three-phase DC/AC inverter. Series resistors added to the inverter output to maintain same current in each inverter of the two parallel inverters, and to reduce the circulating current in the parallel inverters to the minimum. Third harmonic injection PWM (THIPWM) reduces the total harmonic distortion and to make maximum use of the voltage source. DSP was used to generate the THIPWM and the control algorithm for the converter. PID controller is applied on the full-bridge DC/DC converter side to maintain the AC voltage to the required level. Selected experimental results have been shown to validate the proposed system.

Journal of Applied Sciences, 2009

ABSTRACT

IEEE GCC Conference & Exhibition, 2011

This paper presents a new technique for accurate fault location based on voltage measurement from... more This paper presents a new technique for accurate fault location based on voltage measurement from one end of the two-terminal transmission line and Smooth Support Vector Machine (SSVM). Due to common problems of current transformer during fault location and as a result increasing the cost and reduction of the accuracy, proposed technique is independent of current measurement and based on one terminal voltage measurement of the transmission line. Post-fault voltage at one end of the line is measured and used in calculation of the fault location. GPS (global positioning system) is not required for this technique resulting in a reduction of economic cost. Using the proposed technique, fault location can be estimated with a lower than 0.025% error without using current transformers and GPS. EMTP/ATP simulation and SSVM results show that the proposed fault location technique is independent of fault type, fault resistance and fault inception of the transmission line.

Power and Energy, IEEE International Conference on, 2010

This paper presents a new technique for accurate fault locator based on synchronized voltage meas... more This paper presents a new technique for accurate fault locator based on synchronized voltage measurement and smooth support vector machines (SSVM) HV teed feeder transmission line. The approach consists of detection of faulted branch, classification of fault type and determination of exact fault location. Post-fault measured voltages waveforms are collected from only two ends of the three branches teed feeder

Problem statement: Most Nickel based Hastelloy C-276 is a difficult-to-machine material because o... more Problem statement: Most Nickel based Hastelloy C-276 is a difficult-to-machine material because of its low thermal diffusive property and high strength at high temperature. Machinability consideration of nickel based Hastelloy C-276 in turning operations has been carried out using ceramic inserts under dry conditions. Approach: This study described a modification approach applied to a fuzzy logic based model for predicting cutting force where the machining parameters for cutting speed ranges, feed rate, depth of cut and approach angle are not overlapping. For this study, data were selected depending on the design of experiments. Response surface methodology was applied to predict the cutting force and to examine the fuzzy logic based model. Results: The modification approach fuzzy logic based model produced the cutting force data providing good correlation with response surface data. In this situation the cutting force data were superimposed and results were adjusted according to their own ranges. Conclusion: A review of literatures on optimization techniques revealed that there were, in particular, successful industrial applications of design of experiment-based approaches for optimal settings of process variables.

We investigate the behavior of a uniform cantilever beam with a small mass at its tip. The beam c... more We investigate the behavior of a uniform cantilever beam with a small mass at its tip. The beam can move out of a rigid body; thus, its span varies with time. The body can have no motion or can be spinning; both simulations are considered. The reasons for such investigations are: (1) it is the subject of current interest in connection with the recent developments in the space and robotics fields; and (2) to study the behavior analytically because very few analytical solutions are available. The interest here is in the linear vibratory motions of the beam with the objective of developing approximate asymptotic expressions for the beam displacements. A formulation of the problem is made which accounts for the time mass. Two ways to eject the beam out of the system are considered: root force ejection and time dependent acceleration field ejection. The assumed modes method is adopted to derive the corresponding modal equations that describe the in-plane lateral deflections of the beam. The case when there is no tip mass is also included. Approximate asymptotic expressions for the beam displacement are presented for three types of length variations: uniform, exponential, and a linear variation of the square of the length. In the course of the analysis, the system is allowed to spin about an axis normal to the ejection direction, and modal equations governing vibrations in and out of the plane of rotation are derived. Approximate expressions for the beam displacement are presented in the absence of the tip mass for the three length variations mentioned previously. An approximate solution for the beam loaded by a tip mass is presented only for uniform length variations. The results from the investigation are discussed.

International Journal of Electrical Power & Energy Systems, 2014

and sharing with colleagues.

2013 IEEE Conference on Clean Energy and Technology (CEAT), 2013

ABSTRACT Renewable energy sources This paper presents a comparison between five different cities ... more ABSTRACT Renewable energy sources This paper presents a comparison between five different cities in term of wind and solar energy potentials. It first describes the Weibull distribution functions and then analyzes the data collected from the Malaysian Meteorological Department. It then shows the average wind speed and the operation probability of a wind turbine with a cut in speed of 2.5m/s over the five chosen cities. Power density at the wind turbine's hub height is calculated with the annual operating hours of the turbine. Second, this paper compares the power output of a certain PV module in these five different cities. The implication of this study is that it gives an overall review on the wind and solar energy potentials in Malaysia and its results are significant for feasibility and optimization studies. The data obtained from the Malaysian Meteorological Department are on a daily basis from 2011 to 2012.

2011 IEEE GCC Conference and Exhibition (GCC), 2011

This paper presents a new technique for accurate fault location based on voltage measurement from... more This paper presents a new technique for accurate fault location based on voltage measurement from one end of the two-terminal transmission line and Smooth Support Vector Machine (SSVM). Due to common problems of current transformer during fault location and as a result increasing the cost and reduction of the accuracy, proposed technique is independent of current measurement and based on one terminal voltage measurement of the transmission line. Post-fault voltage at one end of the line is measured and used in calculation of the fault location. GPS (global positioning system) is not required for this technique resulting in a reduction of economic cost. Using the proposed technique, fault location can be estimated with a lower than 0.025% error without using current transformers and GPS. EMTP/ATP simulation and SSVM results show that the proposed fault location technique is independent of fault type, fault resistance and fault inception of the transmission line.

2010 IEEE International Conference on Power and Energy, 2010

This paper presents a new technique for accurate fault locator based on synchronized voltage meas... more This paper presents a new technique for accurate fault locator based on synchronized voltage measurement and smooth support vector machines (SSVM) HV teed feeder transmission line. The approach consists of detection of faulted branch, classification of fault type and determination of exact fault location. Post-fault measured voltages waveforms are collected from only two ends of the three branches teed feeder