Nassir Mokhlif - Academia.edu (original) (raw)

Papers by Nassir Mokhlif

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects

AIMS Energy

When it comes to renewable energy, solar water heaters are among the fastest-growing technologies... more When it comes to renewable energy, solar water heaters are among the fastest-growing technologies. Comparatively speaking, integrated collector-storage solar water heater systems cost less than other solar water heater designs. Therefore, both the construction and the operation of a combined collector-storage solar water heater are quite straightforward. The integrated storage solar collector coupled with reflectors has been experimentally investigated. The reflectors were insulated from the back side when working during the day hours and as insulated cover during the night hours. While comparing the combined collector-storage solar water heater with and without insulated reflectors, the results showed that the insulated reflectors increased the thermal efficiency by 23%. Furthermore, on the coldest day, the stored water reached a high of 82 degrees Celsius, though it was only 46 degrees Celsius that same morning.

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects

Tikrit Journal of Engineering Sciences

In this research, an empirical study has been done to find fouling factor for water flowing insid... more In this research, an empirical study has been done to find fouling factor for water flowing inside air-cooled plate finned radiator with constant heat flux beside the boundary condition of the thermal process. The research also required practical tests for finite period time(twenty days for each test). Two kinds of treated water that used in cooling towers was used to show the agreement between calculated fouling factor and this treatment. The work required test specific radiator in the beginning to calculate a design fouling factor that compared with others results with keeping the operation conditions constant. A simulation computer program required to enters all the boundary conditions for the heat system besides the correlating equations for the heat transfer of the radiator. The results show a good inspection for the fouling factor that agrees the practical analysis for the water treatment.

International Journal of Oil, Gas and Coal Technology, 2017

The deposition and gelation of paraffin wax are among the significant risks in flow assurance dur... more The deposition and gelation of paraffin wax are among the significant risks in flow assurance during crude oil transportation. These risks are highly influenced by the structure of hydrocarbons in the produced composition from the well. In the present paper, four crude oil samples acquired from different Malaysian fields were experimentally analysed through gas chromatography/mass spectrometry, differential scanning calorimetry, and thermal gravimetric analyses. The crudes were investigated, with focus on the carbon number distribution, wax appearance temperature, and wax content. The results demonstrate that the crude oil samples with high molecular percentage of carbon distribution within a range of C20 to C40 comprehend high wax content. Measurement results of the four investigated crude samples revealed that the wax content is relatively high compared to other crudes produced in East Asian fields. Also, the four samples possess low wax appearance temperature characteristics, and all four crudes might behave as non-Newtonian at temperature around 38°C. The results provide useful information to manage the risk of wax formation in the transportation pipeline and the flow assurance of the crude. [Received: August 30, 2015; Accepted: July, 24, 2016].

2011 National Postgraduate Conference, 2011

Recent work in commerce search has shown that understanding the semantics in user queries enables... more Recent work in commerce search has shown that understanding the semantics in user queries enables more effective query analysis and retrieval of relevant products. However, due to lack of sufficient domain knowledge, user queries often include terms that cannot be mapped directly to any product attribute. For example, a user looking for designer handbags might start with such a query because she is not familiar with the manufacturers, the price ranges, and/or the material that gives a handbag designer appeal. Current commerce search engines treat terms such as designer as keywords and attempt to match them to contents such as product reviews and product descriptions, often resulting in poor user experience. In this study, we propose to address this problem by reformulating queries involving terms such as designer, which we call modifiers, to queries that specify precise product attributes. We learn to rewrite the modifiers to attribute values by analyzing user behavior and leveraging structured data sources such as the product catalog that serves the queries. We first produce a probabilistic mapping between the modifiers and attribute values based on user behavioral data. These initial associations are then used to retrieve products from the catalog, over which we infer sets of attribute values that best describe the semantics of the modifiers. We evaluate the effectiveness of our approach based on a comprehensive Mechanical Turk study. We find that users agree with the attribute values selected by our approach in about 95% of the cases and they prefer the results surfaced for our reformulated queries to ones for the original queries in 87% of the time.

Journal of Applied Sciences, 2011

Journal of Applied Sciences, 2012

Renewable Energy

Abstract The target of this work is to examine the performance of an integrated solar water heate... more Abstract The target of this work is to examine the performance of an integrated solar water heater with corrugated absorber surface. An integrated solar water heater was built and experimentally tested outside so as to observe the temperature variation of water in the storage tank. The present solar water heater capacity is 140 L. Two cases have been studied, which are with and without flow rate. In case of without flow rate, the maximum value of stored water temperature obtained is 58 °C and 78 °C during winter and spring seasons, respectively. The stored water temperature got in the present work is higher than for the previous work principally attributable to the corrugated absorber of the storage tank. In case of with load, the daily thermal efficiency values of the solar collector were 59%, 65%, and 67%, when the mass flow rate values were 0.005 kg/s, 0.0091 kg/s, and 0.013 kg/s, respectively. The outcomes demonstrate that a large thermal losses from the system was observed during the night hours. In addition, the present integrated solar water heater is success to provide hot water suitable to use by the human during the winter and spring seasons of Iraq.

Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax ... more Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax crystallization phenomena in the solvent dewaxing process. In this paper, comparisons are implemented between different methods to investigate the wax characteristics of SN500 feedstock before and after dewaxing. The measurements involved were the wax content, wax appearance temperature, wax disappearence temperature, solid mass yield of the wax removal. The measurement methods adopted in the analysis are the modified Universal Oil Production method 46-64, Differential Scanning Calorimetry thermal analyzer, Cross Polar Microscopy technique, and Gas Chromatography analysis. Results have demonstrated that the modified Universal Oil Production method is slightly under estimating the wax content in the feedstock compared to the DSC results. This under estimation becomes larger for the wax content in the base stock.

This paper presents a numerical model describe the kinetic of wax crystallization in scraped surf... more This paper presents a numerical model describe the kinetic of wax crystallization in scraped surface exchangers that mostly used in solvent dewaxing as a separation technique. The model consists of a combination between the heat transfer and the kinetic of wax crystallization. Solvent dewaxing process is selectivity reduced the higher normal paraffin components. This fact provides easier handling of the characteristic of the kinetics of wax crystallization, physical properties, and flow behavior. Chemical analyses of the feedstock are important to specify the carbon number distribution, dissolved temperature, and wax content. Wax crystallization in scraped surface heat exchanger is dependent of a large number of variables and is still subject of unclassified researches within few companies. Such process as affected by multi-parameters, need a mathematical description of wax crystallization to predict e.g. the mass fraction, the crystals number, their size, and temperature distributi...

Materials Today: Proceedings, 2021

The design of an integrated solar water heating system uses a single glazed cover does not keep t... more The design of an integrated solar water heating system uses a single glazed cover does not keep the water heat at suitable temperature due to the heat loss occurred. This article is concerned about the effect of a double glass panel cover on the efficacy of the integrated solar water heater of an absorber made of metals with corrugated shape. A testbed was developed and used to conduct outdoor experiments. Two case scenarios were experimented, without flow rate and with a flow rate. The water temperature variation for both scenarios was observed and recorded for the 140 Liters storage tank. Due to the proposed thermal design enhancement, the temperature of the stored water had increased in both scenarios, compared to previous designs. In other words, the daily thermal efficiency got increased compares to previous designs as the heat losses were reduced due to the double-glazing cover. The results showed that domestic hot water appropriate for human use can be obtained using the proposed integrated solar water heater. Moreover, the present study in comparison with previous studies show increasing in daily thermal efficiency by 4.6%.

Materials Today: Proceedings

Journal of Applied Sciences, 2014

Advanced Materials Research, 2014

Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax ... more Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax crystallization phenomena in the solvent dewaxing process. In this paper, comparisons are implemented between different methods to investigate the wax characteristics of SN500 feedstock before and after dewaxing. The measurements involved were the wax content, wax appearance temperature, wax disappearence temperature, solid mass yield of the wax removal. The measurement methods adopted in the analysis are the modified Universal Oil Production method 46-64, Differential Scanning Calorimetry thermal analyzer, Cross Polar Microscopy technique, and Gas Chromatography analysis. Results have demonstrated that the modified Universal Oil Production method is slightly under estimating the wax content in the feedstock compared to the DSC results. This under estimation becomes larger for the wax content in the base stock.

International Journal of Chemical Engineering and Applications, 2014

www.elsevier.com/locate/renene, 2019

The target of this work is to examine the performance of an integrated solar water heater with co... more The target of this work is to examine the performance of an integrated solar water heater with corrugated absorber surface. An integrated solar water heater was built and experimentally tested outside so as to observe the temperature variation of water in the storage tank. The present solar water heater capacity is 140 L. Two cases have been studied, which are with and without flow rate. In case of without flow rate, the maximum value of stored water temperature obtained is 58 C and 78 C during winter and spring seasons, respectively. The stored water temperature got in the present work is higher than for the previous work principally attributable to the corrugated absorber of the storage tank. In case of with load, the daily thermal efficiency values of the solar collector were 59%, 65%, and 67%, when the mass flow rate values were 0.005 kg/s, 0.0091 kg/s, and 0.013 kg/s, respectively. The outcomes demonstrate that a large thermal losses from the system was observed during the night hours. In addition, the present integrated solar water heater is success to provide hot water suitable to use by the human during the winter and spring seasons of Iraq.

Inderscience Enterprises Ltd, 2017

The deposition and gelation of paraffin wax are among the significant risks in flow assurance dur... more The deposition and gelation of paraffin wax are among the significant risks in flow assurance during crude oil transportation. These risks are highly influenced by the structure of hydrocarbons in the produced composition from the well. In the present paper, four crude oil samples acquired from different Malaysian fields were experimentally analysed through gas chromatography/mass spectrometry, differential scanning calorimetry, and thermal gravimetric analyses. The crudes were investigated, with focus on the carbon number distribution, wax appearance temperature, and wax content. The results demonstrate that the crude oil samples with high molecular percentage of carbon distribution within a range of C 20 to C 40 comprehend high wax content. Measurement results of the four investigated crude samples revealed that the wax content is relatively high compared to other crudes produced in East Asian fields. Also, the four samples possess low wax appearance temperature characteristics, and all four crudes might behave as non-Newtonian at temperature around 38°C. The results provide useful information to manage the risk of wax formation in the transportation pipeline and the flow assurance of the crude. [

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects

AIMS Energy

When it comes to renewable energy, solar water heaters are among the fastest-growing technologies... more When it comes to renewable energy, solar water heaters are among the fastest-growing technologies. Comparatively speaking, integrated collector-storage solar water heater systems cost less than other solar water heater designs. Therefore, both the construction and the operation of a combined collector-storage solar water heater are quite straightforward. The integrated storage solar collector coupled with reflectors has been experimentally investigated. The reflectors were insulated from the back side when working during the day hours and as insulated cover during the night hours. While comparing the combined collector-storage solar water heater with and without insulated reflectors, the results showed that the insulated reflectors increased the thermal efficiency by 23%. Furthermore, on the coldest day, the stored water reached a high of 82 degrees Celsius, though it was only 46 degrees Celsius that same morning.

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects

Tikrit Journal of Engineering Sciences

In this research, an empirical study has been done to find fouling factor for water flowing insid... more In this research, an empirical study has been done to find fouling factor for water flowing inside air-cooled plate finned radiator with constant heat flux beside the boundary condition of the thermal process. The research also required practical tests for finite period time(twenty days for each test). Two kinds of treated water that used in cooling towers was used to show the agreement between calculated fouling factor and this treatment. The work required test specific radiator in the beginning to calculate a design fouling factor that compared with others results with keeping the operation conditions constant. A simulation computer program required to enters all the boundary conditions for the heat system besides the correlating equations for the heat transfer of the radiator. The results show a good inspection for the fouling factor that agrees the practical analysis for the water treatment.

International Journal of Oil, Gas and Coal Technology, 2017

The deposition and gelation of paraffin wax are among the significant risks in flow assurance dur... more The deposition and gelation of paraffin wax are among the significant risks in flow assurance during crude oil transportation. These risks are highly influenced by the structure of hydrocarbons in the produced composition from the well. In the present paper, four crude oil samples acquired from different Malaysian fields were experimentally analysed through gas chromatography/mass spectrometry, differential scanning calorimetry, and thermal gravimetric analyses. The crudes were investigated, with focus on the carbon number distribution, wax appearance temperature, and wax content. The results demonstrate that the crude oil samples with high molecular percentage of carbon distribution within a range of C20 to C40 comprehend high wax content. Measurement results of the four investigated crude samples revealed that the wax content is relatively high compared to other crudes produced in East Asian fields. Also, the four samples possess low wax appearance temperature characteristics, and all four crudes might behave as non-Newtonian at temperature around 38°C. The results provide useful information to manage the risk of wax formation in the transportation pipeline and the flow assurance of the crude. [Received: August 30, 2015; Accepted: July, 24, 2016].

2011 National Postgraduate Conference, 2011

Recent work in commerce search has shown that understanding the semantics in user queries enables... more Recent work in commerce search has shown that understanding the semantics in user queries enables more effective query analysis and retrieval of relevant products. However, due to lack of sufficient domain knowledge, user queries often include terms that cannot be mapped directly to any product attribute. For example, a user looking for designer handbags might start with such a query because she is not familiar with the manufacturers, the price ranges, and/or the material that gives a handbag designer appeal. Current commerce search engines treat terms such as designer as keywords and attempt to match them to contents such as product reviews and product descriptions, often resulting in poor user experience. In this study, we propose to address this problem by reformulating queries involving terms such as designer, which we call modifiers, to queries that specify precise product attributes. We learn to rewrite the modifiers to attribute values by analyzing user behavior and leveraging structured data sources such as the product catalog that serves the queries. We first produce a probabilistic mapping between the modifiers and attribute values based on user behavioral data. These initial associations are then used to retrieve products from the catalog, over which we infer sets of attribute values that best describe the semantics of the modifiers. We evaluate the effectiveness of our approach based on a comprehensive Mechanical Turk study. We find that users agree with the attribute values selected by our approach in about 95% of the cases and they prefer the results surfaced for our reformulated queries to ones for the original queries in 87% of the time.

Journal of Applied Sciences, 2011

Journal of Applied Sciences, 2012

Renewable Energy

Abstract The target of this work is to examine the performance of an integrated solar water heate... more Abstract The target of this work is to examine the performance of an integrated solar water heater with corrugated absorber surface. An integrated solar water heater was built and experimentally tested outside so as to observe the temperature variation of water in the storage tank. The present solar water heater capacity is 140 L. Two cases have been studied, which are with and without flow rate. In case of without flow rate, the maximum value of stored water temperature obtained is 58 °C and 78 °C during winter and spring seasons, respectively. The stored water temperature got in the present work is higher than for the previous work principally attributable to the corrugated absorber of the storage tank. In case of with load, the daily thermal efficiency values of the solar collector were 59%, 65%, and 67%, when the mass flow rate values were 0.005 kg/s, 0.0091 kg/s, and 0.013 kg/s, respectively. The outcomes demonstrate that a large thermal losses from the system was observed during the night hours. In addition, the present integrated solar water heater is success to provide hot water suitable to use by the human during the winter and spring seasons of Iraq.

Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax ... more Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax crystallization phenomena in the solvent dewaxing process. In this paper, comparisons are implemented between different methods to investigate the wax characteristics of SN500 feedstock before and after dewaxing. The measurements involved were the wax content, wax appearance temperature, wax disappearence temperature, solid mass yield of the wax removal. The measurement methods adopted in the analysis are the modified Universal Oil Production method 46-64, Differential Scanning Calorimetry thermal analyzer, Cross Polar Microscopy technique, and Gas Chromatography analysis. Results have demonstrated that the modified Universal Oil Production method is slightly under estimating the wax content in the feedstock compared to the DSC results. This under estimation becomes larger for the wax content in the base stock.

This paper presents a numerical model describe the kinetic of wax crystallization in scraped surf... more This paper presents a numerical model describe the kinetic of wax crystallization in scraped surface exchangers that mostly used in solvent dewaxing as a separation technique. The model consists of a combination between the heat transfer and the kinetic of wax crystallization. Solvent dewaxing process is selectivity reduced the higher normal paraffin components. This fact provides easier handling of the characteristic of the kinetics of wax crystallization, physical properties, and flow behavior. Chemical analyses of the feedstock are important to specify the carbon number distribution, dissolved temperature, and wax content. Wax crystallization in scraped surface heat exchanger is dependent of a large number of variables and is still subject of unclassified researches within few companies. Such process as affected by multi-parameters, need a mathematical description of wax crystallization to predict e.g. the mass fraction, the crystals number, their size, and temperature distributi...

Materials Today: Proceedings, 2021

The design of an integrated solar water heating system uses a single glazed cover does not keep t... more The design of an integrated solar water heating system uses a single glazed cover does not keep the water heat at suitable temperature due to the heat loss occurred. This article is concerned about the effect of a double glass panel cover on the efficacy of the integrated solar water heater of an absorber made of metals with corrugated shape. A testbed was developed and used to conduct outdoor experiments. Two case scenarios were experimented, without flow rate and with a flow rate. The water temperature variation for both scenarios was observed and recorded for the 140 Liters storage tank. Due to the proposed thermal design enhancement, the temperature of the stored water had increased in both scenarios, compared to previous designs. In other words, the daily thermal efficiency got increased compares to previous designs as the heat losses were reduced due to the double-glazing cover. The results showed that domestic hot water appropriate for human use can be obtained using the proposed integrated solar water heater. Moreover, the present study in comparison with previous studies show increasing in daily thermal efficiency by 4.6%.

Materials Today: Proceedings

Journal of Applied Sciences, 2014

Advanced Materials Research, 2014

Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax ... more Measurements of wax-in-feedstock parameters are vital tools for successful simulation of the wax crystallization phenomena in the solvent dewaxing process. In this paper, comparisons are implemented between different methods to investigate the wax characteristics of SN500 feedstock before and after dewaxing. The measurements involved were the wax content, wax appearance temperature, wax disappearence temperature, solid mass yield of the wax removal. The measurement methods adopted in the analysis are the modified Universal Oil Production method 46-64, Differential Scanning Calorimetry thermal analyzer, Cross Polar Microscopy technique, and Gas Chromatography analysis. Results have demonstrated that the modified Universal Oil Production method is slightly under estimating the wax content in the feedstock compared to the DSC results. This under estimation becomes larger for the wax content in the base stock.

International Journal of Chemical Engineering and Applications, 2014

www.elsevier.com/locate/renene, 2019

The target of this work is to examine the performance of an integrated solar water heater with co... more The target of this work is to examine the performance of an integrated solar water heater with corrugated absorber surface. An integrated solar water heater was built and experimentally tested outside so as to observe the temperature variation of water in the storage tank. The present solar water heater capacity is 140 L. Two cases have been studied, which are with and without flow rate. In case of without flow rate, the maximum value of stored water temperature obtained is 58 C and 78 C during winter and spring seasons, respectively. The stored water temperature got in the present work is higher than for the previous work principally attributable to the corrugated absorber of the storage tank. In case of with load, the daily thermal efficiency values of the solar collector were 59%, 65%, and 67%, when the mass flow rate values were 0.005 kg/s, 0.0091 kg/s, and 0.013 kg/s, respectively. The outcomes demonstrate that a large thermal losses from the system was observed during the night hours. In addition, the present integrated solar water heater is success to provide hot water suitable to use by the human during the winter and spring seasons of Iraq.

Inderscience Enterprises Ltd, 2017

The deposition and gelation of paraffin wax are among the significant risks in flow assurance dur... more The deposition and gelation of paraffin wax are among the significant risks in flow assurance during crude oil transportation. These risks are highly influenced by the structure of hydrocarbons in the produced composition from the well. In the present paper, four crude oil samples acquired from different Malaysian fields were experimentally analysed through gas chromatography/mass spectrometry, differential scanning calorimetry, and thermal gravimetric analyses. The crudes were investigated, with focus on the carbon number distribution, wax appearance temperature, and wax content. The results demonstrate that the crude oil samples with high molecular percentage of carbon distribution within a range of C 20 to C 40 comprehend high wax content. Measurement results of the four investigated crude samples revealed that the wax content is relatively high compared to other crudes produced in East Asian fields. Also, the four samples possess low wax appearance temperature characteristics, and all four crudes might behave as non-Newtonian at temperature around 38°C. The results provide useful information to manage the risk of wax formation in the transportation pipeline and the flow assurance of the crude. [