Change search
Refine search result
1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Arslan, Muhammad
    et al.
    University of Engineering and Technology, Pakistan..
    Farooq, Muhammad
    University of Engineering and Technology, Pakistan..
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sultan, Umair
    MNS University of Agriculture, Pakistan..
    Tahir, Zia-ur-Rehman
    University of Engineering and Technology, Pakistan..
    Nawaz, Saad
    University of Engineering and Technology, Pakistan..
    Waheed, Nazim
    University of Engineering and Technology, Pakistan..
    Naqvi, Salman Raza
    National University of Sciences and Technology, Pakistan.
    Ali, Qasim
    University of Sargodha, Pakistan..
    Tariq, M. Suleman
    University of Engineering and Technology, Pakistan..
    Chaudhry, Ijaz Ahmad
    University of Management and Technology, Pakistan..
    Anderson, John M.
    Heriot-Watt University, Scotland..
    Anukam, Anthony
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator2020In: Processes, ISSN 2227-9717, Vol. 8, no 3, article id 352Article in journal (Refereed)
    Abstract [en]

    Modeling and optimization of a double-inlet pulse tube refrigerator (DIPTR) is very difficult due to its geometry and nature. The objective of this paper was to optimize-DIPTR through experiments with the cold heat exchanger (CHX) along the comparison of cooling load with experimental data using different boundary conditions. To predict its performance, a detailed two-dimensional DIPTR model was developed. A double-drop pulse pipe cooler was used for solving continuity, dynamic and power calculations. External conditions for applicable boundaries include sinusoidal pressure from an end of the tube from a user-defined function and constant temperature or limitations of thermal flux within the outer walls of exchanger walls under colder conditions. The results of the system's cooling behavior were reported, along with the connection between the mass flow rates, heat distribution along pulse tube and cold-end pressure, the cooler load's wall temp profile and cooler loads with varied boundary conditions i.e. opening of 20% double-inlet and 40-60% orifice valves, respectively. Different loading conditions of 1 and 5W were applied on the CHX. At 150 K temperature of the cold-end heat exchanger, a maximum load of 3.7 W was achieved. The results also reveal a strong correlation between computational fluid dynamics modeling results and experimental results of the DIPTR.

  • 2.
    Farooq, Muhammad
    et al.
    Univ Engn & Technol, Lahore , Pakistan.;Heriot Watt Univ, t, Edinburgh, Scotland..
    Hamayoun, Ahsan
    Univ Engn & Technol, Lahore, Pakistan..
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Nawaz, Saad
    Univ Engn & Technol, Lahore, Pakistan..
    Usman, Muhammad
    Univ Engn & Technol, Lahore, Pakistan..
    Naqvi, Salman Raza
    Natl Univ Sci & Technol, Islamabad, Pakistan..
    Imran, Muhammad
    Aston Univ, , Birmingham, England..
    Nadeem, Rida
    Univ Engn & Technol Lahore, Pakistan..
    Razi, Allah
    Univ Engn & Technol, Lahore, Pakistan..
    Turan, Ahmet
    Yalova Univ, Turkey..
    Pettinau, Alberto
    Sotacarbo SpA, Grande Miniera Serbariu, Carbonia, Italy..
    Andresen, John M.
    Heriot Watt Univ,, Edinburgh , Scotland..
    Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment2020In: Processes, ISSN 2227-9717, Vol. 8, no 2, article id 187Article in journal (Refereed)
    Abstract [en]

    Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation's high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)-5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment.

  • 3.
    Frodeson, Stefan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Berghel, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Ståhl, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Granström, Karin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Romlin, Carl
    Drinor AB, Karlstad.
    Thelander, Alexander
    Drinor AB, Karlstad,.
    The Potential for a Pellet Plant to Become a Biorefinery2019In: Processes, ISSN 2227-9717, Vol. 7, no 4, p. 1-11, article id 233Article in journal (Refereed)
    Abstract [en]

    The use of bioenergy has increased globally in recent years, as has the utilization of biomaterials for various new product solutions through various biorefinery concepts. In this study, we introduce the concept of using a mechanical dewatering press in combination with thermal drying in a pellet plant. The purpose of the study is to increase the understanding of the effects a mechanical dewatering press has in a pellet production chain and investigate whether a pellet plant could thus become a biorefinery. The evaluations in this study are based on industrial data and initial tests at the university. The results show that the concept of using the mechanical dewatering press together with a packed moving bed dryer reduces energy use by 50%, compared to using only a packed moving bed dryer. The press water could be used as a raw material for biogas, bioplastics, and biohydrogen. Hence, this study points out the possibilities of a pellet plant increasing the efficiency of the drying step, while moving towards becoming a biorefinery.

    Download full text (pdf)
    fulltext
  • 4.
    Jamil, Asif
    et al.
    Univ Engn & Technol, Dept Chem Polymer & Composite Mat Engn, New Campus, Lahore 39021, Pakistan..
    Ching, Oh Pei
    Univ Teknol Petronas, Dept Chem Engn, Inst Contaminant Management, CO2 Res Ctr CO2RES, Bandar Seri Iskandar 32610, Perak, Malaysia..
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). ..
    Khan, Hafiza Aroosa Aslam
    Univ Engn & Technol, Dept Chem Polymer & Composite Mat Engn, New Campus, Lahore Pakistan..
    Naqvi, Salman Raza
    Natl Univ Sci & Technol, Islamabad Pakistan..
    Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes: CO2 Permeance Study via Theoretical Models2020In: Processes, ISSN 2227-9717, Vol. 8, no 1, article id 118Article in journal (Refereed)
    Abstract [en]

    The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang-Cussler, Lape-Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO2 permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (%AARE) values till 3 wt. % f-MMT loading in the range of +/- 10 for a pressure range of 2 to 10 bar. Hence, Bharadwaj was the best fit model for the experimental data compared to other models, as it considers the platelets orientation.

  • 5.
    Usman, Muhammad
    et al.
    Univ Engn & Technol, Mech Engn Dept, Lahore , Pakistan..
    Farooq, Muhammad
    Univ Engn & Technol, Mech Engn Dept, Lahore , Pakistan..
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Saleem, Muhammad Wajid
    Univ Engn & Technol, Mech Engn Dept, Lahore , Pakistan..
    Hussain, Jafar
    Univ Engn & Technol, Mech Engn Dept, Lahore, Pakistan..
    Naqvi, Salman Raza
    Natl Univ Sci & Technol, Sch Chem & Mat Engn, Islamabad , Pakistan..
    Jahangir, Shahzaib
    Univ Engn & Technol, Mech Engn Dept, Lahore, Pakistan..
    Jazim Usama, Hafiz Muhammad
    Univ Engn & Technol, Mech Engn Dept, Lahore, Pakistan..
    Idrees, Saad
    Univ Engn & Technol, Mech Engn Dept, Lahore, Pakistan..
    Anukam, Anthony
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Use of Gasoline, LPG and LPG-HHO Blend in SI Engine: A Comparative Performance for Emission Control and Sustainable Environment2020In: Processes, ISSN 2227-9717, Vol. 8, no 1, article id 74Article in journal (Refereed)
    Abstract [en]

    The rising global warming concerns and explosive degradation of the environment requires the mainstream utilization of alternative fuels, such as hydroxy gas (HHO) which presents itself as a viable substitute for extracting the benefits of hydrogen. Therefore, an experimental study of the performance and emission characteristics of alternative fuels in contrast to conventional gasoline was undertaken. For experimentation, a spark ignition engine was run on a multitude of fuels comprising of gasoline, Liquefied petroleum gas (LPG) and hybrid blend of HHO with LPG. The engine was operated at 60% open throttle with engine speed ranging from 1600 rpm to 3400 rpm. Simultaneously, the corresponding performance parameters including brake specific fuel consumption, brake power and brake thermal efficiency were investigated. Emission levels of CO, CO2, HC and NOx were quantified in the specified speed range. To check the suitability of the acquired experimental data, it was subjected to a Weibull distribution fit. Enhanced performance efficiency and reduced emissions were observed with the combustion of the hybrid mixture of LPG with HHO in comparison to LPG: on average, brake power increased by 7% while the brake specific fuel consumption reduced by 15%. On the other hand, emissions relative to LPG decreased by 21%, 9% and 21.8% in cases of CO, CO2, and unburned hydrocarbons respectively. Incorporating alternative fuels would not only imply reduced dependency on conventional fuels but would also contribute to their sustainability for future generations. Simultaneously, the decrease in harmful environmental pollutants would help to mitigate and combat the threats of climate change.

1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf