Ahmed Elkhateeb | Ain Shams University (original) (raw)
Papers by Ahmed Elkhateeb
Applied Acoustics, Dec 1, 2021
Abstract In masjid acoustical design, it is important to consider the effects of different human ... more Abstract In masjid acoustical design, it is important to consider the effects of different human body postures on its sound absorption characteristics. In this study, 15 male subjects were asked to simulate the four Islamic prayer postures (standing, bowing, prostration, and sitting down) to investigate these effects. Additionally, a fifth posture was considered wherein the participants sat down randomly on the floor, simulating the case of worshippers listening to the Friday sermon. Measurements were performed twice in a reverberation room, following ISO 354:2003. The first set of measurements was performed while the participants simulated prayer directly on the bare floor (Setup 1), whereas the second set was performed while prayer was simulated on a carefully selected masjid carpet installed over a polyethylene foam padding (Setup 2). The results confirmed the human subjects’ ability to absorb sound waves in the mid- and high-frequency bands and highlighted the absorption dependence on body posture. In the mid-frequency band for both setups, standing in well-defined rows yielded the highest equivalent sound absorption area per object, AObj (Setup 1 mean = 0.49 m2, Setup 2 mean = 0.70 m2), whereas prostration in well-defined rows yielded the lowest AObj value (Setup 1 mean = 0.34, Setup 2 mean = 0.54 m2). The effects of clothing and carpets on sound absorption by the human body were also revealed. Finally, different approaches for incorporating these findings in acoustic simulation software were discussed.
Applied Acoustics, Jul 1, 2021
Abstract Iwan masjids (mosques) represent a milestone in the history of masjid architecture. This... more Abstract Iwan masjids (mosques) represent a milestone in the history of masjid architecture. This style was very common in the Mamluk state, which ruled Egypt between 1250 and 1517 CE. Due to its historical value, the present work investigates the effects of the architectural features of these masjids (closed and semi-closed) on their acoustic characteristics. Twenty masjids (9 semi-closed and 11 closed) were carefully selected. These masjids were subjected to detailed architectural and acoustic surveys. In the acoustic survey, room impulse responses were collected utilizing the integrated impulse response method in accordance with ISO, 3382-1:2009. The different architectural parameters and acoustic indicators for the investigated rooms were calculated based on the collected data. Results demonstrated a clear tendency to increase the reverberation in these buildings through increasing the room’s height thus its volume. In the semi-closed masjids, the average reverberation in the mid-frequency range, unoccupied, was found to be 1.86 s (decreasing to 1.29 s, when occupied) for an average volume of 1,659 m3. In the closed masjids, it was 1.54 s (decreasing to 1.11 s, when occupied) for an average volume of 1,995 m3. Results also showed a strong, positive, statistically significant, correlation and relationship between room volume and its mid-range reverberation. Based on these findings, it is recommended that the reverberation be augmented by increasing the volume per person; in all cases, this should not fall below 7.00 m3/person.
Ain Shams Engineering Journal, Sep 1, 2012
Industrial & Engineering Chemistry Research, Dec 6, 2022
Acoustics Australia, Oct 19, 2019
Nexus Network Journal, May 21, 2014
Nexus Network Journal, Jun 27, 2014
Building Acoustics, Jun 1, 2012
ABSTRACT This work assesses effects of the modern pyramidal forms versus the traditional forms on... more ABSTRACT This work assesses effects of the modern pyramidal forms versus the traditional forms on the acoustical qualities inside the Masjids (Mosques). For this purpose; three rooms were acoustically compared utilizing ODEON ver. 4.2. They are: a pyramidal room (MRM), the reference room )RR) and a right rectangular prismatic room (CUB). Results showed that MRM exhibits the shortest T in comparison with CUB and RR. In case of MRM, if its internal space was left free from any obstruction (columns or slabs like mezzanine); it has the highest values for speech indicators among the others (D50 0.41 (SI 90 %) and STI 0.24). CUB has the next shortest T whereas RR has the longest T. Results also showed that CUB and RR together have very close values for speech indicators (D50 0.36, and 0.375, (SI 86 %) respectively, and STI 0.24 for both).
Nexus Network Journal, Sep 9, 2014
Routledge eBooks, Nov 18, 2019
Frontiers of Architectural Research, Sep 1, 2021
Abstract Walking experience through urban spaces is a frequent daily activity. Thus, planning and... more Abstract Walking experience through urban spaces is a frequent daily activity. Thus, planning and designing for walkability become crucial for building up quality of life. Our daily walks around the city are affected by fulfilling the needed psychological contentment that is in turn measured unconsciously by our temporal perception. This contentment is inherent in what we experience in accordance with urban ambiance that goes beyond the spatial attributes of spaces to include their social and sensorial dimensions. Thus, the question here is how walkability of urban routes is affected by urban ambiance and therefore perceived in terms of time. Therefore, this study aims to understate the trilateral interrelation of walkability, temporal perception, and urban ambiance in walkable routes for daily routine use. This work depends on an experimental study where participants are asked to walk along two selected routes. Data-gathering tools rely on documenting the lived experience of the target group via reporting their trips and answering a questionnaire. Pattern analysis demonstrates this trilateral interrelation to clarify the interplay. This study concludes specific qualities of walkable routes for routine use that reduce sense of time, which is highly crucial to be realized in such daily walk journeys.
International journal of architectural engineering technology, Dec 22, 2022
ABSTRACT This work introduces an integral concept and a clear mechanism for scientific research m... more ABSTRACT This work introduces an integral concept and a clear mechanism for scientific research methodology that can be applied on every scientific research. The suggested mechanism consists of four subsequent phases: the first is the problem definition and hypothesis phase, the second is the data collection phase, the third is the analysis phase and finally the inference phase. Through this mechanism, the author goes beyond many classifications and categorization to wider horizons. The paper analyzes and criticizes some of the literatures in the field to emphasize that what is usually classified as research methodology is not always what is meant, but can be better described as methods for data collection which. The work also diagnoses some of the most important problems (or diseases) that results because researchers are not always aware of real scientific methodology and its mechanism. Due to the importance of inference in the scientific research, the paper highlights the concept of inference and its parts with a special reference to Deductive versus Inductive inference that constitute the heart of scientific research.
Applied Acoustics, 2021
Abstract In masjid acoustical design, it is important to consider the effects of different human ... more Abstract In masjid acoustical design, it is important to consider the effects of different human body postures on its sound absorption characteristics. In this study, 15 male subjects were asked to simulate the four Islamic prayer postures (standing, bowing, prostration, and sitting down) to investigate these effects. Additionally, a fifth posture was considered wherein the participants sat down randomly on the floor, simulating the case of worshippers listening to the Friday sermon. Measurements were performed twice in a reverberation room, following ISO 354:2003. The first set of measurements was performed while the participants simulated prayer directly on the bare floor (Setup 1), whereas the second set was performed while prayer was simulated on a carefully selected masjid carpet installed over a polyethylene foam padding (Setup 2). The results confirmed the human subjects’ ability to absorb sound waves in the mid- and high-frequency bands and highlighted the absorption dependence on body posture. In the mid-frequency band for both setups, standing in well-defined rows yielded the highest equivalent sound absorption area per object, AObj (Setup 1 mean = 0.49 m2, Setup 2 mean = 0.70 m2), whereas prostration in well-defined rows yielded the lowest AObj value (Setup 1 mean = 0.34, Setup 2 mean = 0.54 m2). The effects of clothing and carpets on sound absorption by the human body were also revealed. Finally, different approaches for incorporating these findings in acoustic simulation software were discussed.
Frontiers of Architectural Research, 2021
Abstract This paper investigates the noise inside a metro coach running through the most recent t... more Abstract This paper investigates the noise inside a metro coach running through the most recent tunnel of Cairo. The study focuses on the effects of alignment profiles on the A-weighted noise level. Although the latest line has not been studied yet, noise levels inside the old lines attracted the attention of researchers due to their importance as the first mass transit system in Africa. Given that windows are usually kept open, measurements were conducted inside the empty cabin at the end of the train with open windows according to ISO 3381:2005. Results showed that noise emissions inside the running coaches are high and do not follow either international or general national legislation, which presents health hazards for drivers and commuters. Speech intelligibility is required for train radio units and driver consoles for voice communications, which provides a safe working environment for the train crew. The present study reveals that tight curves mainly contribute to high noise. The noise levels are further raised by the reflective surface of the tunnel with a circular cross-section and the unballasted track. Moreover, the noise level is affected by the location of the coach and window conditions (open/close) to some extent.
Acoustics Australia, 2020
International Journal of Architectural Research: ArchNet-IJAR, 2018
Prayer hall, where traditional Muslim prayers take place, is the most important element of Masjid... more Prayer hall, where traditional Muslim prayers take place, is the most important element of Masjids (mosques). Prayer halls are historically shaped as simple orthogonal walled spaces. Over time, little changes have occurred to them. Recently, with the evolution of architectural schools of thought and the advent of new construction and electromechanical systems, prayer halls have been subject to creativity and experimentation. Architects designed prayer halls with different shapes, spatial configurations and forms which, in some instances, contradict with the essentials of prayer. This research attempts to monitor and classify different types of contemporary prayer halls according to their spatial configuration with special reference to the Saudi Arabian context. Taking the city of Jeddah as a case study, a representative sample of masjids is surveyed, documented, analyzed and classified. The analysis is based on shape, enclosure, symmetry and complexity of prayer halls space. The stu...
Frontiers of Architectural Research, 2017
Applied Acoustics, Dec 1, 2021
Abstract In masjid acoustical design, it is important to consider the effects of different human ... more Abstract In masjid acoustical design, it is important to consider the effects of different human body postures on its sound absorption characteristics. In this study, 15 male subjects were asked to simulate the four Islamic prayer postures (standing, bowing, prostration, and sitting down) to investigate these effects. Additionally, a fifth posture was considered wherein the participants sat down randomly on the floor, simulating the case of worshippers listening to the Friday sermon. Measurements were performed twice in a reverberation room, following ISO 354:2003. The first set of measurements was performed while the participants simulated prayer directly on the bare floor (Setup 1), whereas the second set was performed while prayer was simulated on a carefully selected masjid carpet installed over a polyethylene foam padding (Setup 2). The results confirmed the human subjects’ ability to absorb sound waves in the mid- and high-frequency bands and highlighted the absorption dependence on body posture. In the mid-frequency band for both setups, standing in well-defined rows yielded the highest equivalent sound absorption area per object, AObj (Setup 1 mean = 0.49 m2, Setup 2 mean = 0.70 m2), whereas prostration in well-defined rows yielded the lowest AObj value (Setup 1 mean = 0.34, Setup 2 mean = 0.54 m2). The effects of clothing and carpets on sound absorption by the human body were also revealed. Finally, different approaches for incorporating these findings in acoustic simulation software were discussed.
Applied Acoustics, Jul 1, 2021
Abstract Iwan masjids (mosques) represent a milestone in the history of masjid architecture. This... more Abstract Iwan masjids (mosques) represent a milestone in the history of masjid architecture. This style was very common in the Mamluk state, which ruled Egypt between 1250 and 1517 CE. Due to its historical value, the present work investigates the effects of the architectural features of these masjids (closed and semi-closed) on their acoustic characteristics. Twenty masjids (9 semi-closed and 11 closed) were carefully selected. These masjids were subjected to detailed architectural and acoustic surveys. In the acoustic survey, room impulse responses were collected utilizing the integrated impulse response method in accordance with ISO, 3382-1:2009. The different architectural parameters and acoustic indicators for the investigated rooms were calculated based on the collected data. Results demonstrated a clear tendency to increase the reverberation in these buildings through increasing the room’s height thus its volume. In the semi-closed masjids, the average reverberation in the mid-frequency range, unoccupied, was found to be 1.86 s (decreasing to 1.29 s, when occupied) for an average volume of 1,659 m3. In the closed masjids, it was 1.54 s (decreasing to 1.11 s, when occupied) for an average volume of 1,995 m3. Results also showed a strong, positive, statistically significant, correlation and relationship between room volume and its mid-range reverberation. Based on these findings, it is recommended that the reverberation be augmented by increasing the volume per person; in all cases, this should not fall below 7.00 m3/person.
Ain Shams Engineering Journal, Sep 1, 2012
Industrial & Engineering Chemistry Research, Dec 6, 2022
Acoustics Australia, Oct 19, 2019
Nexus Network Journal, May 21, 2014
Nexus Network Journal, Jun 27, 2014
Building Acoustics, Jun 1, 2012
ABSTRACT This work assesses effects of the modern pyramidal forms versus the traditional forms on... more ABSTRACT This work assesses effects of the modern pyramidal forms versus the traditional forms on the acoustical qualities inside the Masjids (Mosques). For this purpose; three rooms were acoustically compared utilizing ODEON ver. 4.2. They are: a pyramidal room (MRM), the reference room )RR) and a right rectangular prismatic room (CUB). Results showed that MRM exhibits the shortest T in comparison with CUB and RR. In case of MRM, if its internal space was left free from any obstruction (columns or slabs like mezzanine); it has the highest values for speech indicators among the others (D50 0.41 (SI 90 %) and STI 0.24). CUB has the next shortest T whereas RR has the longest T. Results also showed that CUB and RR together have very close values for speech indicators (D50 0.36, and 0.375, (SI 86 %) respectively, and STI 0.24 for both).
Nexus Network Journal, Sep 9, 2014
Routledge eBooks, Nov 18, 2019
Frontiers of Architectural Research, Sep 1, 2021
Abstract Walking experience through urban spaces is a frequent daily activity. Thus, planning and... more Abstract Walking experience through urban spaces is a frequent daily activity. Thus, planning and designing for walkability become crucial for building up quality of life. Our daily walks around the city are affected by fulfilling the needed psychological contentment that is in turn measured unconsciously by our temporal perception. This contentment is inherent in what we experience in accordance with urban ambiance that goes beyond the spatial attributes of spaces to include their social and sensorial dimensions. Thus, the question here is how walkability of urban routes is affected by urban ambiance and therefore perceived in terms of time. Therefore, this study aims to understate the trilateral interrelation of walkability, temporal perception, and urban ambiance in walkable routes for daily routine use. This work depends on an experimental study where participants are asked to walk along two selected routes. Data-gathering tools rely on documenting the lived experience of the target group via reporting their trips and answering a questionnaire. Pattern analysis demonstrates this trilateral interrelation to clarify the interplay. This study concludes specific qualities of walkable routes for routine use that reduce sense of time, which is highly crucial to be realized in such daily walk journeys.
International journal of architectural engineering technology, Dec 22, 2022
ABSTRACT This work introduces an integral concept and a clear mechanism for scientific research m... more ABSTRACT This work introduces an integral concept and a clear mechanism for scientific research methodology that can be applied on every scientific research. The suggested mechanism consists of four subsequent phases: the first is the problem definition and hypothesis phase, the second is the data collection phase, the third is the analysis phase and finally the inference phase. Through this mechanism, the author goes beyond many classifications and categorization to wider horizons. The paper analyzes and criticizes some of the literatures in the field to emphasize that what is usually classified as research methodology is not always what is meant, but can be better described as methods for data collection which. The work also diagnoses some of the most important problems (or diseases) that results because researchers are not always aware of real scientific methodology and its mechanism. Due to the importance of inference in the scientific research, the paper highlights the concept of inference and its parts with a special reference to Deductive versus Inductive inference that constitute the heart of scientific research.
Applied Acoustics, 2021
Abstract In masjid acoustical design, it is important to consider the effects of different human ... more Abstract In masjid acoustical design, it is important to consider the effects of different human body postures on its sound absorption characteristics. In this study, 15 male subjects were asked to simulate the four Islamic prayer postures (standing, bowing, prostration, and sitting down) to investigate these effects. Additionally, a fifth posture was considered wherein the participants sat down randomly on the floor, simulating the case of worshippers listening to the Friday sermon. Measurements were performed twice in a reverberation room, following ISO 354:2003. The first set of measurements was performed while the participants simulated prayer directly on the bare floor (Setup 1), whereas the second set was performed while prayer was simulated on a carefully selected masjid carpet installed over a polyethylene foam padding (Setup 2). The results confirmed the human subjects’ ability to absorb sound waves in the mid- and high-frequency bands and highlighted the absorption dependence on body posture. In the mid-frequency band for both setups, standing in well-defined rows yielded the highest equivalent sound absorption area per object, AObj (Setup 1 mean = 0.49 m2, Setup 2 mean = 0.70 m2), whereas prostration in well-defined rows yielded the lowest AObj value (Setup 1 mean = 0.34, Setup 2 mean = 0.54 m2). The effects of clothing and carpets on sound absorption by the human body were also revealed. Finally, different approaches for incorporating these findings in acoustic simulation software were discussed.
Frontiers of Architectural Research, 2021
Abstract This paper investigates the noise inside a metro coach running through the most recent t... more Abstract This paper investigates the noise inside a metro coach running through the most recent tunnel of Cairo. The study focuses on the effects of alignment profiles on the A-weighted noise level. Although the latest line has not been studied yet, noise levels inside the old lines attracted the attention of researchers due to their importance as the first mass transit system in Africa. Given that windows are usually kept open, measurements were conducted inside the empty cabin at the end of the train with open windows according to ISO 3381:2005. Results showed that noise emissions inside the running coaches are high and do not follow either international or general national legislation, which presents health hazards for drivers and commuters. Speech intelligibility is required for train radio units and driver consoles for voice communications, which provides a safe working environment for the train crew. The present study reveals that tight curves mainly contribute to high noise. The noise levels are further raised by the reflective surface of the tunnel with a circular cross-section and the unballasted track. Moreover, the noise level is affected by the location of the coach and window conditions (open/close) to some extent.
Acoustics Australia, 2020
International Journal of Architectural Research: ArchNet-IJAR, 2018
Prayer hall, where traditional Muslim prayers take place, is the most important element of Masjid... more Prayer hall, where traditional Muslim prayers take place, is the most important element of Masjids (mosques). Prayer halls are historically shaped as simple orthogonal walled spaces. Over time, little changes have occurred to them. Recently, with the evolution of architectural schools of thought and the advent of new construction and electromechanical systems, prayer halls have been subject to creativity and experimentation. Architects designed prayer halls with different shapes, spatial configurations and forms which, in some instances, contradict with the essentials of prayer. This research attempts to monitor and classify different types of contemporary prayer halls according to their spatial configuration with special reference to the Saudi Arabian context. Taking the city of Jeddah as a case study, a representative sample of masjids is surveyed, documented, analyzed and classified. The analysis is based on shape, enclosure, symmetry and complexity of prayer halls space. The stu...
Frontiers of Architectural Research, 2017