Araz Alizadeh - Academia.edu (original) (raw)
Papers by Araz Alizadeh
PLOS ONE, 2020
Nowadays, citizen science has become increasingly popular, especially in Western countries. In Ho... more Nowadays, citizen science has become increasingly popular, especially in Western countries. In Hong Kong, citizen science projects are mostly used for public education, while utilizing citizen scientists in published scientific research is very rare. On the other hand, with the increasing threats to global water security, Hong Kong requires new adaptation and strategy in facing the impairment of local freshwater systems. However, unfortunately, the number of full-scale urban river research appears to be declining. In this regard, citizen science can offer an alternative option as one of the new integrated water management strategies in Hong Kong. In this study, the water quality of seven rivers and streams in Hong Kong was studied monthly for two years by a group of citizen scientists. The main goal is to examine the reliability of data collected by citizen scientists by comparing it with the official data from the Environmental Protection Department of Hong Kong (EPD). Results show that the water temperature and conductivity data acquired by the citizen scientists were highly comparable to the official data. Also, moderate to strong correlations in water pH, turbidity, and dissolved oxygen levels were found between citizen scientists and official data. Since the citizen science data remained as high as 70% of relevance to the official data, we believe that this may serve as a supplement to the lacking official or professional water quality monitoring data in Hong Kong. Even though the use of volunteer data in water quality monitoring unavoidably exists with errors and bias, this study demonstrates a successful outcome of utilizing citizen science programme in urban river monitoring in Hong Kong.
Sustainable Cities and Society, 2019
As regards the number of electric vehicles and their batteries energy variety in charging or disc... more As regards the number of electric vehicles and their batteries energy variety in charging or discharging modes, the vehicle to grid technology can act as a variable load in charging mode or as a variable energy source in discharging mode. In this paper, a new approach is proposed. In the proposed approach, the control of the connection node voltage and the coordination of the charging and discharging of the EVs batteries are considered as the variable objective functions. The constraints are determined by several parameters such as the state of charge, connection node voltage, and charging-discharging time. Based on the proposed approach, the decision variables (which are active and reactive powers) exchanged between the EVs aggregator and the grid, are determined to achieve the defined objective functions. Reduction of grid losses in the peak load hours is the other advantage of the proposed approach. The simulations for a typical distribution system with V2G capabilities based on the proposed approach are carried out and tested for the different scenarios in charging and discharging modes. Finally, for lending credence to the proposed method, results are compared with conventional method.
Marine Environmental Research, 2012
Nitrate (N) and phosphate (P) are believed to be two of the most important nutrients for the grow... more Nitrate (N) and phosphate (P) are believed to be two of the most important nutrients for the growth and toxin production for Alexandrium species. The study of the growth and toxicity characteristics of the Alexandrium spp. under the change of N and P can help us to understand the dynamics of algal bloom and toxification events in natural environments. A strain of Alexandrium tamarense (designated as Kci) was successfully isolated from the Drake Passage in 2001 and the clonal culture has been kept in our laboratory (Ho et al., 2003, 2012). In order to extend our understanding on the growth physiology and toxicity of this A. tamarense strain, growth and cellular toxin content were examined in unialgal batch cultures under different concentrations of N and P. The effects of variable N, P concentrations on growth, cellular toxicity (fg STXeq. cell(-1)), and toxin composition (% molar) were determined in both exponential and stationary growth phases. The toxin profile, determined by high-performance liquid chromatography with fluorescence detection (HPLC-FD), was found to be remained relatively stable and was consistently dominated by the N-sulfocarbamoyl C-toxins (>90%) under different conditions and growth phases. There were also trace amounts of other carbamate gonyautoxins consistently expressed. The cellular toxicity varied under different N and P concentrations, as well as different growth stages. A positive correlation was observed between cellular toxicity and N concentrations, but the toxicity was enhanced when P was depleted. Both cell densities and growth rate of the cells were severely suppressed under N- or P-depletion. However, the biovolume of the cells tended to be larger at N- or P-depleted cultures. Results from the present study provide valuable insight for the ecophysiology of Alexandrium species in the coastal ecosystem of Drake Passage.
Journal of Microbiological Methods, 2008
Two-dimensional gel electrophoresis (2-DE) is one of the most efficient ways of resolving complex... more Two-dimensional gel electrophoresis (2-DE) is one of the most efficient ways of resolving complex protein mixtures based on the isoelectric point (pI) and molecular mass (M r). Although it has been used extensively in proteomic studies on samples from the animal and plant kingdoms, there is limited information on its use on algae, such as dinoflagellates. The preparation of high-quality samples from dinoflagellate cells for 2-DE is difficult due to high endogenous levels of salts, nucleic acids, polysaccharides, phenolic compounds, pigments, and other interfering compounds. Desalting and concentrating steps are usually required for the preparation of dinoflagellate protein sample prior to 2-DE and these steps can be lengthy and complicated. In this study, we report the use of Trizol (a monophasic solution of phenol and guanidine isothiocyanate) for the extraction of proteins from dinoflagellate cells for 2-DE. The method is simple and fast. 2-DE profiles obtained with Trizol treatment are of very high quality in terms of resolution, spot number and spot intensity. This method greatly simplifies protein extraction procedures on dinoflagellate samples for obtaining a high quality and reproductive 2-DE profile. This methodology is generally applicable to algal samples.
Current Proteomics, 2007
Abstract: Proteins are the major players in most processes of living cells and study of the prote... more Abstract: Proteins are the major players in most processes of living cells and study of the proteome has great relevance to investigations on cells and organisms at the molecular level. 2-DE is a core and powerful proteomic technique to study protein expression and function in living ...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2022
Air-cooled heat exchangers are utilized in various industries to cool process fluids. To have a b... more Air-cooled heat exchangers are utilized in various industries to cool process fluids. To have a better heat transfer, fins are used in the structure of exchangers. In this study, a set of experiments were performed to investigate the improvement in the amount of heat transfer in an air-cooled heat exchanger. For this purpose, a real case study was conducted on air-coolers in a natural gas compressor station; afterward, the finned tubes were replaced by pulsating heat pipes (PHPs), and a different type of fluid was applied to the pulsating heat pipes. The laboratory system was set up to measure the overall heat transfer coefficient under two conditions involving either finned tubes or a PHP with R134, R22, and filled acetone fluids. Finally, the results were verified by the theory method. The results showed that all the three fluid agents (R134, R22, and Acetone) with natural convection of 9.94 m/s, an inlet fluid velocity of 5.54 m/s, and an average feed velocity were able to enhanc...
AIMS Energy, 2020
In natural gas pressure boosting stations, air coolers are used to reduce the gas temperature. Pr... more In natural gas pressure boosting stations, air coolers are used to reduce the gas temperature. Pressure drop as an essential factor in determining the energy performance of any pressure boosting station has a significant impact on the overall performance of the gas transmission. In this paper, a laboratory pilot is designed to investigate the effect of pressure drop reduction on the use of heating pipes at the air coolers. In addition, as a case for a gas pressure boosting station, its impact over energy performance index and pressure drop parameter has been calculated through simulating. The results show, implemented PHP tubes in an air cooler, lead to reduce tube length and improve pressure drop, 44.59, 40.4, 36.78, 23.34% in four gas flow rate. Also, this approach decreased fuel gas consumption more than 1,114,000 Sm3 and 3,889,440 kWh electrical consumption in air coolers, annually. Beside, investigation of energy performance indicators reveals that this approach might improve the total energy performance, thermal performance and electrical energy performance indices up to 3, 2.3 and 79%, respectively.
Energy Science & Engineering, 2019
One of the ways to improve heat transfer efficiency is to use a spiral structure for tubes instea... more One of the ways to improve heat transfer efficiency is to use a spiral structure for tubes instead of conventional direct tubes. Compared to the direct tubes, spiral tubes have a more compact surface and have higher heat transfer and friction coefficients. When the fluid flows through the spiral tubes, it influences by the centrifugal force which this centrifugal force creates a secondary flow in the fluid, and as a result, this secondary flow increases the axial flow velocity near the outer wall of the tube. Thereby increasing the axial velocity will reduce the thermal resistance and
Natural gas compressor stations in gas transmission industries cause to increase gas pressure and... more Natural gas compressor stations in gas transmission industries cause to increase gas pressure and discharge to gas transmission pipeline. Air coolers in compressor station, have high electrical energy consumption and pressure drop. In this investigation, the application of heat pipe heat exchangers (HPHE) in a case study of the gas compressor station is evaluated to use instead of air coolers. The result of the investigation shows that applying 620 heat pipes with a 50% filling ratio, working fluid R134 and arranged triangularly, can reduce the compressed natural gas temperature. Energy performance analysis shows that using this method improves total, thermal, and electrical energy performance indicators (3%, 2.4 %, and 78%, respectively). Also simulating process demonstrate that using HPHE cause to save 1,115,000 SCM fuel in gas turbine and 3,800 MWh electrical saving in air coolers. In addition, results show with using HPHE 2,615,000 $ cost saving is available and project payback ...
PLOS ONE, 2020
Nowadays, citizen science has become increasingly popular, especially in Western countries. In Ho... more Nowadays, citizen science has become increasingly popular, especially in Western countries. In Hong Kong, citizen science projects are mostly used for public education, while utilizing citizen scientists in published scientific research is very rare. On the other hand, with the increasing threats to global water security, Hong Kong requires new adaptation and strategy in facing the impairment of local freshwater systems. However, unfortunately, the number of full-scale urban river research appears to be declining. In this regard, citizen science can offer an alternative option as one of the new integrated water management strategies in Hong Kong. In this study, the water quality of seven rivers and streams in Hong Kong was studied monthly for two years by a group of citizen scientists. The main goal is to examine the reliability of data collected by citizen scientists by comparing it with the official data from the Environmental Protection Department of Hong Kong (EPD). Results show that the water temperature and conductivity data acquired by the citizen scientists were highly comparable to the official data. Also, moderate to strong correlations in water pH, turbidity, and dissolved oxygen levels were found between citizen scientists and official data. Since the citizen science data remained as high as 70% of relevance to the official data, we believe that this may serve as a supplement to the lacking official or professional water quality monitoring data in Hong Kong. Even though the use of volunteer data in water quality monitoring unavoidably exists with errors and bias, this study demonstrates a successful outcome of utilizing citizen science programme in urban river monitoring in Hong Kong.
Sustainable Cities and Society, 2019
As regards the number of electric vehicles and their batteries energy variety in charging or disc... more As regards the number of electric vehicles and their batteries energy variety in charging or discharging modes, the vehicle to grid technology can act as a variable load in charging mode or as a variable energy source in discharging mode. In this paper, a new approach is proposed. In the proposed approach, the control of the connection node voltage and the coordination of the charging and discharging of the EVs batteries are considered as the variable objective functions. The constraints are determined by several parameters such as the state of charge, connection node voltage, and charging-discharging time. Based on the proposed approach, the decision variables (which are active and reactive powers) exchanged between the EVs aggregator and the grid, are determined to achieve the defined objective functions. Reduction of grid losses in the peak load hours is the other advantage of the proposed approach. The simulations for a typical distribution system with V2G capabilities based on the proposed approach are carried out and tested for the different scenarios in charging and discharging modes. Finally, for lending credence to the proposed method, results are compared with conventional method.
Marine Environmental Research, 2012
Nitrate (N) and phosphate (P) are believed to be two of the most important nutrients for the grow... more Nitrate (N) and phosphate (P) are believed to be two of the most important nutrients for the growth and toxin production for Alexandrium species. The study of the growth and toxicity characteristics of the Alexandrium spp. under the change of N and P can help us to understand the dynamics of algal bloom and toxification events in natural environments. A strain of Alexandrium tamarense (designated as Kci) was successfully isolated from the Drake Passage in 2001 and the clonal culture has been kept in our laboratory (Ho et al., 2003, 2012). In order to extend our understanding on the growth physiology and toxicity of this A. tamarense strain, growth and cellular toxin content were examined in unialgal batch cultures under different concentrations of N and P. The effects of variable N, P concentrations on growth, cellular toxicity (fg STXeq. cell(-1)), and toxin composition (% molar) were determined in both exponential and stationary growth phases. The toxin profile, determined by high-performance liquid chromatography with fluorescence detection (HPLC-FD), was found to be remained relatively stable and was consistently dominated by the N-sulfocarbamoyl C-toxins (>90%) under different conditions and growth phases. There were also trace amounts of other carbamate gonyautoxins consistently expressed. The cellular toxicity varied under different N and P concentrations, as well as different growth stages. A positive correlation was observed between cellular toxicity and N concentrations, but the toxicity was enhanced when P was depleted. Both cell densities and growth rate of the cells were severely suppressed under N- or P-depletion. However, the biovolume of the cells tended to be larger at N- or P-depleted cultures. Results from the present study provide valuable insight for the ecophysiology of Alexandrium species in the coastal ecosystem of Drake Passage.
Journal of Microbiological Methods, 2008
Two-dimensional gel electrophoresis (2-DE) is one of the most efficient ways of resolving complex... more Two-dimensional gel electrophoresis (2-DE) is one of the most efficient ways of resolving complex protein mixtures based on the isoelectric point (pI) and molecular mass (M r). Although it has been used extensively in proteomic studies on samples from the animal and plant kingdoms, there is limited information on its use on algae, such as dinoflagellates. The preparation of high-quality samples from dinoflagellate cells for 2-DE is difficult due to high endogenous levels of salts, nucleic acids, polysaccharides, phenolic compounds, pigments, and other interfering compounds. Desalting and concentrating steps are usually required for the preparation of dinoflagellate protein sample prior to 2-DE and these steps can be lengthy and complicated. In this study, we report the use of Trizol (a monophasic solution of phenol and guanidine isothiocyanate) for the extraction of proteins from dinoflagellate cells for 2-DE. The method is simple and fast. 2-DE profiles obtained with Trizol treatment are of very high quality in terms of resolution, spot number and spot intensity. This method greatly simplifies protein extraction procedures on dinoflagellate samples for obtaining a high quality and reproductive 2-DE profile. This methodology is generally applicable to algal samples.
Current Proteomics, 2007
Abstract: Proteins are the major players in most processes of living cells and study of the prote... more Abstract: Proteins are the major players in most processes of living cells and study of the proteome has great relevance to investigations on cells and organisms at the molecular level. 2-DE is a core and powerful proteomic technique to study protein expression and function in living ...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2022
Air-cooled heat exchangers are utilized in various industries to cool process fluids. To have a b... more Air-cooled heat exchangers are utilized in various industries to cool process fluids. To have a better heat transfer, fins are used in the structure of exchangers. In this study, a set of experiments were performed to investigate the improvement in the amount of heat transfer in an air-cooled heat exchanger. For this purpose, a real case study was conducted on air-coolers in a natural gas compressor station; afterward, the finned tubes were replaced by pulsating heat pipes (PHPs), and a different type of fluid was applied to the pulsating heat pipes. The laboratory system was set up to measure the overall heat transfer coefficient under two conditions involving either finned tubes or a PHP with R134, R22, and filled acetone fluids. Finally, the results were verified by the theory method. The results showed that all the three fluid agents (R134, R22, and Acetone) with natural convection of 9.94 m/s, an inlet fluid velocity of 5.54 m/s, and an average feed velocity were able to enhanc...
AIMS Energy, 2020
In natural gas pressure boosting stations, air coolers are used to reduce the gas temperature. Pr... more In natural gas pressure boosting stations, air coolers are used to reduce the gas temperature. Pressure drop as an essential factor in determining the energy performance of any pressure boosting station has a significant impact on the overall performance of the gas transmission. In this paper, a laboratory pilot is designed to investigate the effect of pressure drop reduction on the use of heating pipes at the air coolers. In addition, as a case for a gas pressure boosting station, its impact over energy performance index and pressure drop parameter has been calculated through simulating. The results show, implemented PHP tubes in an air cooler, lead to reduce tube length and improve pressure drop, 44.59, 40.4, 36.78, 23.34% in four gas flow rate. Also, this approach decreased fuel gas consumption more than 1,114,000 Sm3 and 3,889,440 kWh electrical consumption in air coolers, annually. Beside, investigation of energy performance indicators reveals that this approach might improve the total energy performance, thermal performance and electrical energy performance indices up to 3, 2.3 and 79%, respectively.
Energy Science & Engineering, 2019
One of the ways to improve heat transfer efficiency is to use a spiral structure for tubes instea... more One of the ways to improve heat transfer efficiency is to use a spiral structure for tubes instead of conventional direct tubes. Compared to the direct tubes, spiral tubes have a more compact surface and have higher heat transfer and friction coefficients. When the fluid flows through the spiral tubes, it influences by the centrifugal force which this centrifugal force creates a secondary flow in the fluid, and as a result, this secondary flow increases the axial flow velocity near the outer wall of the tube. Thereby increasing the axial velocity will reduce the thermal resistance and
Natural gas compressor stations in gas transmission industries cause to increase gas pressure and... more Natural gas compressor stations in gas transmission industries cause to increase gas pressure and discharge to gas transmission pipeline. Air coolers in compressor station, have high electrical energy consumption and pressure drop. In this investigation, the application of heat pipe heat exchangers (HPHE) in a case study of the gas compressor station is evaluated to use instead of air coolers. The result of the investigation shows that applying 620 heat pipes with a 50% filling ratio, working fluid R134 and arranged triangularly, can reduce the compressed natural gas temperature. Energy performance analysis shows that using this method improves total, thermal, and electrical energy performance indicators (3%, 2.4 %, and 78%, respectively). Also simulating process demonstrate that using HPHE cause to save 1,115,000 SCM fuel in gas turbine and 3,800 MWh electrical saving in air coolers. In addition, results show with using HPHE 2,615,000 $ cost saving is available and project payback ...