Now showing 1 - 10 of 33
  • Publication
    Morphological changes analysis using 3D bathymetric surveys in Chilia Branch - Bystroe Channel bifurcation area
    (IOP Publishing, 2023)
    Georgeta Tudor
    ;
    György Deák
    ;
    Marius Raischi
    ;
    Miruna Arsene
    ;
    Elena Holban
    ;
    ;
    The Bystroe Channel project with transboundary environmental impact in the Danube Delta, area of great ecological significance that has already a strong anthropic footprint, requires close monitoring of water quality parameters in order to determine their tendencies and their impact on the ecosystem components. Riverbed bathymetry surveys using multibeam echo-sounders are of high interest due to the data resolution and coverage capabilities that surpass the single-beam methods. Two riverbed elevation datasets, recorded in consecutive years, have been used to carry out morphological comparative analysis for the area where Chilia branch bifurcates in Bystroe Channel and Old Stambul. The analysis has been performed both on the bathymetry grids as a whole and on 3 longitudinal and 9 transversal river sections, the morphological changes values being in majority included in [-0.5 m;+0.5 m], with a minimum of -2.4 m and a maximum of 2.2 m, showing the bifurcation influence on the erosion/deposition processes results.
  • Publication
    Development and implementation of a methodology for National Wastewater Surveillance System of SARS-CoV-2 in Romania
    (IOP Publishing, 2023)
    Raluca Prangate
    ;
    György Deák Habil
    ;
    Monica Silvia Matei
    ;
    Mădalina Georgiana Boboc
    ;
    Ecol Elena Holban
    ;
    SARS-CoV-2 is a pathogenic coronavirus and has caused acute respiratory diseases worldwide. Over time, numerous research studies have proved the benefits of environmental surveillance through monitoring the wastewater. During the COVID-19 public health emergency, several countries have conducted studies to detect viral RNA from SARS-CoV-2 in wastewater. Also, several countries have developed a National Wastewater Surveillance System of SARS-CoV-2, currently it is also being implemented in Romania. The aim of this research is to develop, in line with the already existing volume of information, a methodology for the processing and analysis of wastewater samples for SARS-CoV-2 and to highlight methods for sample preparation (these methods are not standardised). In addition, we summarize current knowledge on recent advances and applicability of SARS-CoV-2 virus monitoring in wastewater as a tool for surveillance of COVID-19.
  • Publication
    Workability and density of concrete containing Coconut Fiber
    Use of natural fiber in concrete to enhance the strength of concrete have been used widely and become as part of an alternative building materials. For instance, the use of coconut fiber (CF) which are non-hazardous, environmental-friendly and can improves the engineering properties of concrete. The aim of this study is to identify the workability and density of CF modified concrete. CF were added into the mixture in 3 different amount that is 200 g, 400 g, and 600 g. The size of the cube samples is 100 × 100 × 100 mm and were cured for 14 days, and 28 days. To evaluate the effect of CF in improving the properties of concrete, the properties of ordinary concrete are used as a reference which consist 0% CF. The fresh and hardened densities for all samples also show that when more fiber was added into mixture, densities reduced. As summary, the study shows that by adding CF in concrete reduced the workability and density of concrete.
      1  29
  • Publication
    Exploring the potential of agricultural waste as natural resource-based adsorbents for methylene blue removal
    ( 2024-01-01) ;
    Muhamad Farid Idham Sulaiman
    ;
    Ain Nihla Kamarudzaman
    ;
    ; ;
    Syakirahafiza Mohammed
    ;
    ;
    Deák G.
    ;
    Excessive agricultural waste in the agricultural industry leads to various forms of pollution, including water pollution. To address this issue, there's a growing interest in finding alternative methods. One approach is to utilize agricultural waste as natural resource-based adsorbents to eliminate contaminants, such as the case of methylene blue (MB) in this study. The study specifically focuses on using rice husk (RH) from a local rice mill in Perlis, Malaysia, to absorb methylene blue. The structure of rice husk, characterized by scanning electron microscopy (SEM), reveals a coarser and more compact outer area, contributing to its absorption capacity for methylene blue. The study on rice husk involves three main aspects: contact time, adsorbent dosage, and dye concentration. The removal percentage of MB increased as the three studied adsorption parameters increased. The adsorption data were analyzed using Langmuir and Freundlich adsorption isotherms, with the the Freundlich Isotherms were found to be more suitable based on higher coefficient of correlation (R2) values compared to Langmuir. The pseudo-second-order kinetics model demonstrated a higher R2value (1.00) compared to the pseudo-first-order model (0.747). The results indicate promising potential for addressing pollution through sustainable means and provide insights into the adsorption process under varying conditions.
      2
  • Publication
    Effect of bottom ash and limestone on the optimum binder content in Hot Mix Asphalt (HMA)
    ( 2022-01-01) ; ;
    Noor Aina Misnon
    ;
    Nurhidayah Hamzah
    ;
    ; ;
    Christina Remmy Entalai
    ;
    Deák György
    One of the most effective and simplest methods to minimize waste as well as reduce the environmental problems associated with waste disposal is by utilizing waste materials as a cement replacement in hot mix asphalt (HMA) mixtures which can provide the same or better stability as the conventional method. Fillers play an important role in the stability and strength of the pavement by filling voids between the aggregate particles in the performance of the HMA mixture. This research investigated the effect of the utilization of different types of filler (bottom ash and limestone) on the optimum binder content of HMA. Flow, stability, stiffness, air void in mix (VIM) and void filled with bitumen (VFB) were determined using the Marshal Method test in order to determine the optimum binder content of HMA for all mineral filler. The results of the Marshall test for each filler have been compared with the JKR standard specification. The optimum binder content for bottom ash, limestone and Ordinary Portland Cement (OPC) was 5.42%, 5.65% and 5.54%, respectively. All values of mineral filler used meet the JKR standard specification, where the range is between 4 and 6%. From the result achieved, the bottom ash has the lower optimum binder content value compared to the limestone and OPC. When the lower binder content is used in the bituminous mixture, the cost for pavement construction will be reduced.
      4  2
  • Publication
    Potential use of foam in the production of lightweight aggregate (LWA) and its performance in foamed concrete
    ( 2020-06-10)
    Mohamad Ibrahim N.
    ;
    ; ; ;
    Nazmi N.
    This paper discusses about the production and characteristic of lightweight bubble aggregate and foamed concrete. Lightweight aggregates (LWA) are produced by mixing an appropriate amount of foam and ordinary Portland cement and pelletized into assigned size and shape. Then, the characteristics of LWA are identified to ensure that aggregate produced can be categorized into LWA with acceptable qualities. For the foamed concrete, its performances are tested and studied by selecting five different percentages for partial substitution of LWA as coarse aggregate. Main aim of the research is to identify the characteristic of lightweight foamed concrete such as density, water absorption, aggregate impact value (AIV), compressive strength after using LWA as an alternative material for construction industry. This aim also in parallel to main idea of reducing the usage of natural coarse aggregate which is granite that is facing serious depletion. Three different percentages of concrete mixtures using LWA have been prepared that consist of 25% and 50% of LWA together with control sample that contained 100% natural coarse aggregate. These three different mixes are produced manually where the mortars, foam, granite and LWA were mixed together in mixer. The samples have undergone several testing including density test, water absorption test and compression test. Microstructure of the samples also was examined using SEM. From the results obtained, foamed concrete that were produced with 25% substitution of LWA showed the highest compressive strength of 10.74 MPa with density of 1735 kg/m3. In conclusion, LWA have shown promising potential to be used in the foamed concrete production.
      1  30
  • Publication
    Recycling municipal solid waste incineration bottom ash as cement replacement in concrete
    Cement was a binder material that used in concrete industry. The cost production was very expensive due to the high global demand. Therefore, as a new alternative to replace the used of cement in concrete, which was bottom ash. The objectives of this study were to investigate properties of cement matric of concrete containing bottom ash, and to observe the ability of bottom ash as a binder. Based on the result on XRF, Ordinary Portland Cement and bottom ash had nearly similar compounds of Calcium and Silica. Results of slump test indicate that concrete contains of 10 %- 30% bottom ash cause the true slump. Determination of the capability and strength of concrete obtained from water absorption test. Percentage of water absorbed increases with increasingly of proportion bottom ash. The strength of concrete for compression test was 27.5 MPa for 10 % of bottom ash that achieved the targeted. Higher percentage of bottom ash replacement affected matrix C-S-H (calcium silicate-hydrate) bond. Interfacial transition zone surface and scanning electron microscope observations confirm these findings. Therefore, municipal solid waste incinerator bottom ash can act partly replace cement in concrete but would not exceed 30% of usage.
      7  36
  • Publication
    Effect of bottom Ash and limestone on the optimum binder content in Hot Mix Asphalt (HMA)
    (Springer Science and Business Media Deutschland GmbH, 2022-01-01) ; ;
    Misnon N.A.
    ;
    Hamzah N.
    ;
    ; ;
    Entalai C.R.
    ;
    Deák G.
    One of the most effective and simplest methods to minimize waste as well as reduce the environmental problems associated with waste disposal is by utilizing waste materials as a cement replacement in hot mix asphalt (HMA) mixtures which can provide the same or better stability as the conventional method. Fillers play an important role in the stability and strength of the pavement by filling voids between the aggregate particles in the performance of the HMA mixture. This research investigated the effect of the utilization of different types of filler (bottom ash and limestone) on the optimum binder content of HMA. Flow, stability, stiffness, air void in mix (VIM) and void filled with bitumen (VFB) were determined using the Marshal Method test in order to determine the optimum binder content of HMA for all mineral filler. The results of the Marshall test for each filler have been compared with the JKR standard specification. The optimum binder content for bottom ash, limestone and Ordinary Portland Cement (OPC) was 5.42%, 5.65% and 5.54%, respectively. All values of mineral filler used meet the JKR standard specification, where the range is between 4 and 6%. From the result achieved, the bottom ash has the lower optimum binder content value compared to the limestone and OPC. When the lower binder content is used in the bituminous mixture, the cost for pavement construction will be reduced.
      2  3
  • Publication
    Preservation of natural resources by utilizing combustion ash in concrete and determination of its engineering properties
    Due to the large amount of combustion ash being thrown into landfills, which can lead to environmental pollution, new alternatives to construction materials can be developed by utilising this combustion ash as a part of the main raw materials, while at the same time helping to preserve natural resources in the concrete manufacturing industry. Generally, using new waste materials will eventually affect the engineering properties of concrete. Therefore, the main objective of this study is to analyse the engineering properties of concrete containing combustion ash as a partial replacement for ordinary Portland cement (OPC). CA can be classified as combustion bottom ash (CBA) and combustion fly ash (CFA). CA is tested for its chemical compositions using X-Ray Fluorescence (XRF), and its four main compositions, which are silica, alumina, iron, and calcium, are examined and discussed extensively. Other testing for the property of CA includes Scanning Electron Microscopic (SEM) and specific gravity testing for coarse aggregate. To produce sustainable concrete from waste, several tests have been conducted to determine the engineering properties of the concrete, such as compressive strength, flexural strength, and splitting tensile strength. Results show that CA, which consists mainly of silica dioxide, contributed to the strength of concrete. SEM images show that CBA has a porous structure with an angular and rough texture, whereas CFA has more rounded particles, which influence the overall compressive strength. Furthermore, it was discovered that as the proportion of CBA utilised increased, the compressive strength, flexural strength, and splitting tensile strength of the concrete improved. Based on the results of the testing, CBA is suggested for use as a supplementary cementitious material in concrete.
      14  30
  • Publication
    Waste to concrete material: Potential Study of Chemical Characterization of Coal Fly Ash and Bottom Ash
    This research focuses on the chemical properties of coal fly ash (CFA) and coal bottom ash (CBA) obtained from Sultan Azlan Shah Power Plant and compares them with the characteristics of ordinary Portland cement (OPC). Coal has been recognised as a significant fuel source in Malaysia, where it is extensively employed in the creation of steel, cement, and power. When coal is burned to create power, several different types of coal ash are created, including fly ash, bottom ash, boiler slag, and clinker. Fly and bottom ash, however, are the main coal ash waste products that have been created. In an effort to create sustainable concrete from waste, a number of studies have been carried out to ascertain the chemical characteristics of fly and bottom ash. These tests include Energy Disperse X-Ray (EDX), Mineralogy (XRD), and X-Ray Fluorescence (XRF). From the SEM result, fly ash has smaller particles and a spherical, uniform shape than bottom ash and cement. Fly and bottom ash from the Sultan Azlan Shah power plant contain a number of elements, including Silicon (Si), Aluminium (Al), Oxygen (O), Calcium (Ca), Titanium (Ti), Iron (Fe), Magnesium (Mg), Potassium (K), Carbon (C), and Sodium, according to Energy Dispersive X-Ray (EDX) test. The fly ash is primarily an amorphous material, with the presence of quartz crystalline phase (SiO2) at 24.3% and bottom ash at 31.1%, according to X-ray Diffraction (XRD) data. For the mullite phase (3AlO3.2SiO2), fly and bottom ash show results of 24.9% and 14.5%, respectively. According to an X-ray fluorescence (XRF) investigation, the main constituents of fly and bottom ash are silica, iron, and alumina. Fly ash is classified as Class F because it has a high concentration of SiO2, Al2O3, and Fe2O3 while OPC has a high CaO value. With the right composition and material preparation, CFA and CBA from the Sultan Azlan Shah Power Plant can be used as a cement replacement in concrete.
      1  31