Siti Khadijah Za'aba
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Preferred name
Siti Khadijah Za'aba
Official Name
Za'aba, Siti Khadijah
Alternative Name
SK Zaaba
Zaaba SK
Zaaba Siti Khadijah
Main Affiliation
Scopus Author ID
36151525400

Research Output

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  • Publication
    Induction of Apoptosis of Melanoma Skin Cancer Cells by Atmospheric Plasma Jet
    ( 2023-01-01)
    Abdullah Z.
    ;
    Siti Khadijah Za'aba
    ;
    Mustaffa M.T.
    ;
    Saidin N.A.
    ;
    Mohtar J.A.
    The apoptotic effect is an important issue in cancer treatment. To achieve this goal, an atmospheric plasma jet (APJ) was set up for use on cultured cells in a temperature-controlled environment. Melanoma skin cancer and normal skin cells were targeted with this device. Following a 5 s plasma exposure, there was a 67% cell death in melanoma skin cancer cells compared with 5% in normal skin cells as measured after 24 h. When the treatment time was increased to 15, a 98% cell death was reported for melanoma skin cancer cells, which was 80% greater than the cell death in normal skin cells. Our observations further indicate that this preferential cell death is largely due to apoptosis. It shows that an APJ is a selective device in the induction of apoptosis in cancer and normal cells. APJ was shown to affect cells directly and indirectly through a plasma-activated medium (PAM). In direct treatment, cells were exposed to plasma while suspended in a culture medium, and in indirect treatment, cells were added to a culture medium previously acti-vated by plasma treatment. PAM was able to induce cell death 29% higher than direct treatment as measured after 48 h. The depth of the growth medium is also one of the factors in the induction of apoptosis of cancer cells. The growth medium protected the cells from plasma exposure. The result shows that the low level (0 mm) of growth medium will cause more cell death as compared with the high level (2 mm) of growth medium. Apoptotic behavior of skin cancer cells was de-duced from the fact that treated cells initially grew and died 12 h following the treatment, while untreated cells continued to grow and proliferate.
  • Publication
    Performance of Two Phase Anaerobic Digestion on Food Waste for Biogas Production
    ( 2022-01-01)
    Zakarya I.A.
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Hilmi N.A.M.
    ;
    Mohd Rashidi Che Beson
    ;
    Matei M.
    Every year, the total amount of solid waste generated in Peninsular Malaysia grew, according to the Malaysia government. The typical solid waste management system practiced in developing country brings many problems that can cause risks and hazards for living things and the environment in Malaysia if there are not managed properly. For example, illegal dumping cause groundwater and soil pollution. The methane gas produced from the landfill causes greenhouse effect. Food waste is categorized under household waste, where it is produced in residential areas, restaurants, cafeteria, markets and commercial areas. Therefore, anaerobic digestion process is introduced for organic waste with higher solids contents such as food waste as an alternative method. The effectiveness of anaerobic digestion process can be investigated through this process. In this study, two phase of anaerobic digesters was proposed. The reactor was operated at a temperature 35 °C, analyzed for biogas production, pH values and C/N ratio. The highest biogas production in this study is 50.4%. For a co-digestion containing more sludge can increase the pH value and biogas production.
  • Publication
    Feature extraction using Radon transform and Discrete Wavelet Transform for facial emotion recognition
    ( 2017-02-08)
    Hasimah Ali
    ;
    Vinothan Sritharan
    ;
    Muthusamy Hariharan
    ;
    Siti Khadijah Za'aba
    ;
    Mohamed Elshaikh Elobaid Said Ahmed
    This paper presents a new pattern framework of using Radon and wavelet transform for facial emotion recognition. The Radon transform is translation and rotation invariants, hence it preserves the variations in pixel intensities. In this work, Radon transform has been used to project the 2D image into Radon space before subjected to Discrete Wavelet Transform (DWT). In DWT framework, the approximate coefficients (cA2) at second level decomposition are extracted and used as informative features to recognize the facial emotion. Since there are a large number of coefficients, hence the principal component analysis (PCA) is applied on the extracted features. The k-nearest neighbor classifier is adopted as classifier to classify seven (anger, disgust, fear, happiness, neutral, sadness and surprise) facial emotions. To evaluate the effectiveness of the proposed method, the JAFFE database has been employed. Based on the results obtained, the proposed method demonstrates the recognition rate of 91.3%, thus it is promising.
      27  12
  • Publication
    Development of five port reflectometer for reflection based sensing system
    ( 2017-03-13)
    Setno Baharuddin
    ;
    Cheng Ee Meng
    ;
    Lee Kim Yee
    ;
    Siti Khadijah Za'aba
    ;
    Nurul Syahirah Khalid
    ;
    Zulkifly Abbas
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Mohd Afendi Rojan
    ;
    Zulkarnay Zakaria
    Five-Port Reflectometer is a microwave passivedevice where it implements the six-port algorithm to measure the complex reflection coefficient of material under test (MUT) through reflection on interface between MUT and microwave sensor. Initially, the Six-Port Reflectometer (SPR) was introduced by Engen in 1977 and major component used insix-port technique was designed in many types. When Riblet and Hanssonproposed ring junction with 5 ports only on 1981. Six ports ring junction has been reduced to five ports. In this paper, a dual frequency five ports ring junction circuit was designed, simulated and fabricated for reflection based sensing system. The fabricated five port ring junction is operating at frequencies of 0.64 GHz and 2.42 GHz. The measured result had good agreement with the simulated results for dual frequencies in terms of magnitude and phase.
      36  6
  • Publication
    Co-digestion of food waste with cow dung by anaerobic digestion for biogas production
    ( 2023-01-01)
    Hilmi N.A.M.
    ;
    Irnis Azura Zakaria
    ;
    Ahmad Anas Nagoor Gunny
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Samah M.F.
    ;
    Daud Z.A.A.M.
    ;
    Beson M.R.C.
    Food waste is categorized under household waste which were produce in large amount every day and it can be a good potential to generate biogas production via anaerobic digestion. In this research, the characteristics of co-digestion process are measured to determine the biogas production between food waste and cow dung. The food waste is co-digest with two different type of cow dung are collected depends on their food consuming (grass:bran); 100% grass and 95% grass: 5% bran. The digester is maintained at 35°C of temperature for mesophilic condition. pH values and C/N ratio are noted until 35 days. The biogas production is analysed by using biogas analyzer. The highest biogas production in this study is 67.2% which are co- digest between food waste and cow dung (100%) compared cow dung (95%) is 53.9% on day 26. This shows that the cow dung (100%) produces more biogas than cow dung (95%). Anaerobic digestion process will best suits for biogas production and for the best utilization of food waste.
      2  22
  • Publication
    Analysis of airbox performance improvement for Modenas model by geometrical analysis
    (IOP Publishing, 2017-10-29)
    Shahriman Abu Bakar
    ;
    Mohamad Syafiq Abdul Khadir
    ;
    Hamid K.A.
    ;
    Mohd Sani Mohamad Hashim
    ;
    Hazry Desa
    ;
    Zuradzman Mohamad Razlan
    ;
    Ruslizam Daud
    ;
    Cheng Ee Meng
    ;
    Siti Khadijah Za'aba
    ;
    Teh W.S.W.
    ;
    Shuaib N.A.
    ;
    Wan K.
    ;
    Ishak A.A.
    Airbox system consist of filter element which greatly influenced the quality air into the engine system. The main objective of this study is to improve the performance of airbox system that attached in MODENAS CT115S engine system. Airbox, an empty air chamber, accumulates the outside air and feed it to the cylinder of the engine for combustion process and contains filter element. The function is to provide cleaner air for greater combustion rate and cleaner emission. The performance of airbox can be influenced by changing the location of the filter element and the geometry of airbox. By changing these parameters, the performance of the airbox system can be enhanced. In this study, the geometry of the airbox inlet has been changed in terms of shape and size. The inlet shape for Design 1 in round shape with a diameter of 43.60 mm. Meanwhile for Design 2, the geometry of airbox inlet was changed to a rectangular shape. Between these two designs, Design 1 provides a better result in terms of mass flow rate (10.41 kg/s), velocity (9.84 m/s) and pressure difference (83.44 kPa). By increasing the performance of airbox, the performance of engine can be increased.
      6  15
  • Publication
    Preliminary analysis of the degradation of methylene blue by using plasma discharge in liquid
    (Universiti Malaysia Perlis, 2018-11)
    N. A. H. Ramli
    ;
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Shahriman Abu Bakar
    This article presents the results of experimental work on the identification of reactive species produced by plasma discharge in liquid. The analysis was conducted using methylene blue (MB) as chemical probe. There are two objectives, 1) to identify the effect of ground electrode configuration to the presence of reactive species and 2) to observe the ground electrode durability. Results showed that, degradation of MB occurred when using 7 kV input supply and insulated ground electrode for 10 minutes. Meanwhile, the other input supply (7.8 kV and 8.6 kV) were unable to degrade MB solution.
      18  2
  • Publication
    Municipal solid waste characterization and quantification as a measure towards effective solid waste management in UniMAP
    ( 2020-12-29)
    Irnis Azura Zakaria
    ;
    Fazhil N.S.A.
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Jamaluddin M.N.F.
    The most common environmental problems in Malaysia is increasing in solid waste generation. Solid waste generation and composition knowledge is compulsory as a benchmark for the decision making in managing municipal solid waste management strategy. The objective of this study was to measure solid waste generation and compare solid waste composition at cafeterias of UniMAP. Three different cafeterias had been chosen as a sampling location. Waste was sorted out into several components such as food waste, plastic, papers, metal, glass, and other types of waste. There is significance difference in data collection between the three locations where the organic waste was the main component in waste composition. Solid waste sampling and laboratory analysis were carried out based on random sampling method by using American Standard Test Method (ASTM) standards for proximate analysis (moisture content, ash content, volatile matter and fixed carbon). Ultimate analysis which is C:N ratio was carried out. Results showed that total municipal solid waste generated during two weeks of collection at School of Manufacturing, Tuanku Tengku Fauziah Residential College (PFI 2) and Tan Sri Aisyah Ghani Residential College (KKTAG) were 459.9 kg (0.1452 kg/p/day), 709.0 kg (0.0292 kg/p/day) and 201.90 kg (0.0163 kg/p/day). Based on this information, a proper waste management can be introduced to treat organic waste such as food waste and paper including inorganic waste efficiently.
      1
  • Publication
    Review on the development of plasma discharge in liquid solution
    ( 2017-03-30)
    Nur Arina Hasmimi Ramli
    ;
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Ammar Zakaria
    ;
    Shahriman Abu Bakar
    Review papers on the basic principles and applications of plasma discharge in liquid have been reported. However, the development of plasma discharge in liquid is not widely reviewed. The aim of this paper is to review on the elements involved in developing plasma discharge in liquid. An overview will be given of the various types of existing power source, working gas, dielectric barrier, electrode material used to produce plasma, and reactive species production inside plasma discharge.
      2  31
  • Publication
    Review on prevention of bacterial adhesion on contact lens using plasma treatment
    ( 2017-03-30)
    Nur Arina Hasmimi Ramli
    ;
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Ammar Zakaria
    ;
    Shahriman Abu Bakar
    Many researches had been conducted to enhance the properties of contact lens. Most of the research conducted discussed on the factors that affect the adhesion process to contact lenses, rate of contact lens contamination, and type of microbe that adhere on the contact lens surface and contact lens casing. Studies on the proposed strategies or technology that can be used to slower down the formation of bacteria on contact lens are being explored. New technologies or strategies to prevent or slow down the adhesion of bacteria on contact lens have become a priority in this area. This review paper covers two main aspects, namely factor that affect the bacteria adhesion on contact lens and also the introduction of plasma treatment as a potential method for contact lens treatment.
      33  5