Development and characterization of modified silicone – dammar coating resin / Rosnah Zakaria

The purpose of this study is to develop and characterized the new modified silicone binder resin. The silicone, synthetic resin bought from Dow Corning Corp. and dammar bought from local supplier. Ten (10) samples were prepared and one of them was silicone resin without dammar. The samples were designated as SD0, SD5, SD10, SD15, SD20, SD25, SD30, SD35, SD40 and SD45. The mixture was coat onto aluminum q-panel using spin coater and left in room temperature for around 7 – 8 days for curing process. The cured samples were undergone the mechanical and electrochemical characteristic. The mechanical characterizations include viscosity, cross-hatch test, pull off test, wetting and impact test. Results for cross hatch test showed that 5-15 wt% of dammar in the silicone resin provide the better adhesion on aluminum q-panel with the edges of the cut are smooth and none of the square lattice detached. In the impact test, no fracture can be observed on the impact surfaces when the 1 kg load was released on SD0 – SD20 dried coating surfaces

Conductivity Studies on K-Carrageenan-Methyl Cellulose Blend as Bio-Polymer Electrolyte / Rosnah Zakaria and Ab Malik Marwan Ali

Solid polymer-based electrolyte materials are a great interest due to their many interesting characteristics such as flexibility, and it is easily prepared into films with a large surface area. Two sets of k-carrageenan-methyl cellulose samples were prepared using the solution casting method. Set 1, the wt% of k-Carrageenan was fixed at 0.1 wt%, while methyl cellulose and NH4I was varied. Set 2, the wt% of methyl-cellulose was fixed to 0.1 wt%, and the carrageenan and NH4I were varied. The functional group of samples were studied using FTIR spectroscopy, and the ionic conductivity was studied using impedance spectroscopy, EIS at room temperature. FTIR spectra from set 1 show a small hump at between the 1500 cm-1 to 1000 cm-1 spectra’s which O=S=O symmetrical vibration from methyl cellulose component. This hump was shifted to higher wavenumber due to the increasing of NH4I wt% in the samples. The second region of set 2’s spectra shows the wavenumber between 2000 cm-1 to 1500 cm-1 is the deformation of H-O-H band interactions and its wavenumber decreasing as the addition of salts increasing. The third region of spectra between 1500 cm-1 to 1000 cm-1 represents the band of O=S=O symmetrical vibration. This bands shifted to the lower wavenumber due to addition of salts, and it became less intense towards salt addition. On the other hand, the best conductivity is 6.00 x 10-8 S cm-1 which belongs to B2 of set 2 with the composition of 0.3 wt% k-carrageenan with 0.1 wt% methylcellulose and 0.6 wt% NH4I salt and the lowest conductivity is 3.19 x 10-9 S cm-1 which its composition is 0.1 wt% k-carrageenan with 0.4 wt% methylcellulose and 0.5 wt% NH4I salt in sample D1 of set 1. In conclusion, the optimum component by weight percentage of k-carrageenan: methyl cellulose: NH4I is 0.3:0.1:0.6

Multi display scan in detecting weld discontinuity of thick carbon steel plate using ultrasonic testing phased array (UTPA) with comparison to conventional ultrasonic testing (UT) / Jeffry Jamil, Syed Yusainee Syed Yahya and Rosnah Zakaria

Non-destructive testing (NDT) is a method of testing and analysis that relies on the application of physical principles to determine the integrity of materials without causing damage. The existence of weld discontinuity can affect the service ability of the structures. Ultrasonic testing Phases Array (UTPA) is advanced ultrasonic testing technology widely practiced in many industries. The multiple ultrasonic elements and electronic time delay will create constructive and destructive interference and steering capability, which could improve detectability compared to a single element of conventional UT. The multi displays presented in A-Scan, S-scan, B-Scan, and C-Scan of UTPA equipment capable of locating, inspecting, and characterise defects within the welded component. Two carbon steel plates with thickness 18 mm and 24 mm were prepared and cut to V-shape configuration and welded using shielded metal arc welding (SMAW) process, labelled as NDE-8826 and NDE-8827 respectively. Both samples were induced with artificial defects of the weld. 16 elements of phased array probe with 0.5 mm pitch and 4 MHz were carried out for this study with encoded scanning to identify weld discontinuity plotted in different types of UT displays. Additional testing was performed using conventional ultrasonic testing (UT) using a 4 MHz probe to compare with the UTPA results and the acceptability of each defect detections. The length and datum of toe crack, slag, and lack of inter run fusion detected by UTPA in NDE-8826 give the same value as the actual value. However, the localisation of the defect is slightly different at 1.0 mm for UT detection. While the detection value for slag gives the same values for UT and UTPA, which also the same as the actual values. The detection of lack of penetration and lack of fusion in sample NDE-8827 was precisely can be detected by UT and UTPA; hence their datum value has slightly different in the centerline crack and porosity at 2.0 mm for UT measurement, and as for UTPA, it was found that the porosity at 3.0 mm which higher value compared to the actual value, 250 mm. From the result, a relevant indication from the UTPA and conventional UT collected it was found that the UTPA technique is capable of improving the Probability of Detection (POD) of defects compared to the conventional UT

Antibiotic resistance of Escherichia coli isolated from chicken in Malaysia

Colibacillosis is an important disease affecting the poultry industry in many countries, caused by the Avian Pathogenic E. coli (APEC): it manifests as various clinical signs. It contributes significantly to economic loss for poultry farmers as a result of high mortality and morbidity in poultry. To overcome this, antibiotics have been widely used to eliminate E. coli infection in poultry farms in recent years. Treatment with antibiotics has been considered as a vital regimen to control E. coli infection at the farm level for many years. However, high frequency of antibiotic resistance of E. coli isolates from chicken has become the centre of attention due to public health importance. The aim of the present study is to determine the multidrug resistant profiles of E. coli strains isolated from chicken. E. coli isolates obtained from clinical cases were re-identified and classified by conventional methods. Multidrug resistant profiles against 13 different antibiotics of 125 E. coli isolates were determined by using disk diffusion method according to Clinical Laboratory Standard Institute (CLSI). Antibiogram revealed that 81.6% of the E. coli isolates showed multidrug resistant profiles to different antibiotics. Most of the E. coli isolates were highly resistant to erythromycin (52.8%), followed with tetracycline (52.0%), spectinomycin (39.2%), trimethoprim (38.4%) and flumequin (37.6%). Out of 125 isolates tested, 19.2% were resistant to more than eight antibiotics, with one isolates found to be multidrug resistant to most of antibiotics except polymyxin B. These findings also demonstrated that most of the isolates were susceptible to antibiotics commonly used for E. coli infections treatment in poultry with lowest resistant score against polymyxin B (92.8%) and colistin (92.0%). Moderate resistant profiles were observed towards amoxycilin (25.6%), apramycin (16%), kanamycin (8.8%) and streptomycin (8.0%). High percentage of multidrug resistance was found among the E. coli isolated from chicken as an indicator to more serious problems in animal health. Therefore, continuous surveillance of antibiotic resistance profiles in chicken and other food animals is crucial to ensure food chain safety

Epigenetic insights and potential modifiers as therapeutic targets in β–thalassemia

Thalassemia, an inherited quantitative globin disorder, consists of two types, α– and β–thalassemia. β–thalassemia is a heterogeneous disease that can be asymptomatic, mild, or even severe. Considerable research has focused on investigating its underlying etiology. These studies found that DNA hypomethylation in the β–globin gene cluster is significantly related to fetal hemoglobin (HbF) elevation. Histone modification reactivates γ-globin gene expression in adults and increases β–globin expression. Down-regulation of γ–globin suppressor genes, i.e., BCL11A, KLF1, HBG-XMN1, HBS1L-MYB, and SOX6, elevates the HbF level. β–thalassemia severity is predictable through FLT1, ARG2, NOS2A, and MAP3K5 gene expression. NOS2A and MAP3K5 may predict the β–thalassemia patient’s response to hydroxyurea, a HbF-inducing drug. The transcription factors NRF2 and BACH1 work with antioxidant enzymes, i.e., PRDX1, PRDX2, TRX1, and SOD1, to protect erythrocytes from oxidative damage, thus increasing their lifespan. A single β–thalassemia-causing mutation can result in different phenotypes, and these are predictable by IGSF4 and LARP2 methylation as well as long non-coding RNA expression levels. Finally, the coinheritance of β–thalassemia with α–thalassemia ameliorates the β–thalassemia clinical presentation. In conclusion, the management of β–thalassemia is currently limited to genetic and epigenetic approaches, and numerous factors should be further explored in the future

Structural and electronic properties of orthorhombic phase Bi₂Se₃ based on first-principles study / Muhammad Zamir Mohyedin ... [et al.]

Bi₂Se₃ is one of the promising materials in thermoelectric devices and is environmentally friendly due to its efficiency to perform in room temperature. Structural and electronic properties of Bi2Se3 were investigated based on the first-principles calculation of density functional theory (DFT) using CASTEP computer code. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalised gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. A comparative study is carried out between the electronic properties of LDA and GGA-PBE. Lattice parameter and band gap are consistent with the other reports. Calculation from LDA is more accurate and has a better agreement than GGA-PBE in describing the lattice parameter of Bi2Se3. Band gap and density of states of LDA show higher electrical conductivity than GGA-PBE. Both LDA and GGA-PBE have same degree of thermal conductivity due to the occurrence of indirect band gap at same range of wave vector

Studies of the absorbance peak on the N719 dye influence by combination between Cadmium Selenide (CdSe)QDs and Zinc Sulfide(ZnS)QDs

The absorption rate of the photoanode can be influenced by the combination between the difference semiconductor quantum dot sensitizer. Six samples were prepared with difference weight percent (wt%) of ZnS from 0% to 50% and constant wt% of CdSe which then will be called as semiconductor QDs were immersed in 0.5mM of N719 dye. The purity of ZnS powder and CdSe powder was determined using x-ray diffraction (XRD).The ultraviolet-visible spectrophotometry (Uv-Vis) use to investigate the absorption spectrum and absorbance peak of this sample. 50 wt% of ZnS is the best composition to increase the absorbance peak of the photoanode. The Cyclic voltammetry (CV) of varying wt% of ZnS, found that the 40 wt% of ZnS is suitable combination for a DSSC’s photoanode and produced the higher current

Studies of the absorbance peak on the N719 dye influence by combination between Cadmium Selenide (CdSe)QDs and Zinc Sulfide(ZnS)QDs

The absorption rate of the photoanode can be influenced by the combination between the difference semiconductor quantum dot sensitizer. Six samples were prepared with difference weight percent (wt%) of ZnS from 0% to 50% and constant wt% of CdSe which then will be called as semiconductor QDs were immersed in 0.5mM of N719 dye. The purity of ZnS powder and CdSe powder was determined using x-ray diffraction (XRD).The ultraviolet-visible spectrophotometry (Uv-Vis) use to investigate the absorption spectrum and absorbance peak of this sample. 50 wt% of ZnS is the best composition to increase the absorbance peak of the photoanode. The Cyclic voltammetry (CV) of varying wt% of ZnS, found that the 40 wt% of ZnS is suitable combination for a DSSC’s photoanode and produced the higher current

Quantum dot solar cell studies on the influence of Cadmium Selenide(CdSe)QDs and the Zinc Sulfide(ZnS)QDs in the photoanode

The mixture between the difference semiconductor quantum dot sensitizer which is cadmium selenide(CdSe) and zinc sulfide (ZnS) into the Dye-synthesis solar cell (DSSCs) can affect the value of resistance and capacity photoanode in the system.In this experiment, each sample consists difference weight percent of Zinc sulfide and the constant weight percent of CdSe. Docter blade technique is used to stick and spread evenly the mixture CdSe/ZnS QD on the surface of the thin film. To prove the assembled of CdSe/ZnS on the thin film were observed using Scanning Electron Microscopy (SEM). The resistance and capacity of the photoanode were characterized by using impedance spectroscopy(EIS). The smallest resistance is 37.1kΩ produce by CdSe/ZnS(20 wt%) and the largest resistance 825KΩ produce by CdSe/ZnS(50 wt%) while the highest capacity is 12 µF in the CdSe/ZnS(40 wt%) and the lowest capacity is CdSe/ZnS(20 wt%) which is 538 nF. The most suitable composition to be used as photoanode is CdSe/ZnS(40 wt%) because it has high capacity and low resistance

Quantum dot solar cell studies on the influence of Cadmium Selenide(CdSe)QDs and the Zinc Sulfide(ZnS)QDs in the photoanode

The mixture between the difference semiconductor quantum dot sensitizer which is cadmium selenide(CdSe) and zinc sulfide (ZnS) into the Dye-synthesis solar cell (DSSCs) can affect the value of resistance and capacity photoanode in the system.In this experiment, each sample consists difference weight percent of Zinc sulfide and the constant weight percent of CdSe. Docter blade technique is used to stick and spread evenly the mixture CdSe/ZnS QD on the surface of the thin film. To prove the assembled of CdSe/ZnS on the thin film were observed using Scanning Electron Microscopy (SEM). The resistance and capacity of the photoanode were characterized by using impedance spectroscopy(EIS). The smallest resistance is 37.1kΩ produce by CdSe/ZnS(20 wt%) and the largest resistance 825KΩ produce by CdSe/ZnS(50 wt%) while the highest capacity is 12 µF in the CdSe/ZnS(40 wt%) and the lowest capacity is CdSe/ZnS(20 wt%) which is 538 nF. The most suitable composition to be used as photoanode is CdSe/ZnS(40 wt%) because it has high capacity and low resistance