The joining of ceramic-metal could be done through a few techniques: brazing, diffusion bonding, friction welding etc. However, the mechanism of ceramic-metal joining was still not properly understood. In this study, alumina rod was bonded to mild steel rod via friction welding technique by using Al 1100 sheet as interlayer. The diameter of the rods was 10 mm. Friction pressure of 20 MPa and forging pressure of 40 MPa were used. Rotational speeds were maintained at 900 rpm and friction times of 2 to 20 seconds were applied. The joining strength was determined through four point bending test. The maximum bending strength, 240 MPa was obtained at the friction times of 20 seconds. Under optical microscope and SEM observation, the deformation of the aluminum interface was clearly obtained. Mechanical interlocking and close contact between the aluminaaluminum and aluminum-mild steel were observed at magnifications of 3000X. The strength of alumina-steel bonding is much dependent on the wettability of the alumina surface by the molten aluminum and the existing of mechanical interlocking between interlayer and sample materials.
Batu Reput’ is primary sediment mineral and abundantly found in Perlis. Perlis is one of the major producers of ‘Batu Reput’ in Malaysia that content large deposit of high-purity dolomite [CaMg (CO3)2]. Pure samples of ‘Batu Reput’ recently explored in the Koperasi Rimba Mas Padang Besar Quarry were investigated for their physical, chemical and mineralogical composition. SEM and XRD analysis methods were applied. The potential of ‘Batu Reput’ as a raw material in fertilizer production was investigated in this paper.
MeSH terms: Calcium Carbonate; Fertilizers; Magnesium; Malaysia; Minerals; Paper
A study on the effect of the modify values of x in CaCu3-xMn4+xO12 system has been carried out with x = 0.1, 0.3, 0.5, 0.7 and 0.9. The materials were prepared via solid-state reaction. The preparation conditions have been optimized using thermogravimetry analysis (TGA) technique. Material formations under the reported conditions have been confirmed by X-ray diffraction (XRD) studies. The results show that the formation of CaCu3Mn4O12 started at calcinations temperature of 600 0 C with the presence of raw material and was formed completely at 850 0 C. Field emission scanning electron microscopy (FESEM) analysis indicated that the increase of x value in the composition had changed the microstructures to be more faceted. The impedance spectrum is characterized by the appearance of two semicircle arcs whose pattern of evolution changes with rise of values x in the CaCu3-xMn4+xMn4O12 system. Bulk resistance (Rb) and grain boundary resistance (Rgb) of CaCu3- xMn4+xO12 decreases form 824.24 : to 98.68 : and 418.18 : to 2.20 : respectively, with the increasing of x value.
CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were added. Due to the differences in the solubilities of the Ca, Cu and Ti, initial variations from ideal stoichiometry and a high solution pH was necessary to obtain stoichiometric CaCu3Ti4O12 precipitates. As precipitated samples were amorphous with CuO phases observed after drying of the precipitates at 300 oC. CaCu3Ti4O12 phases were observed after heat treatment at 1000 oC. XRD studies show the presence of CuO and TiO2 in addition to the CaCu3Ti4O12 for non stoichiometric samples. Observations under the SEM show the presence of Cu rich and Ti rich phases in addition to the CaCu3Ti4O12.
Fly ash is the finely divided mineral residue resulting from the combustion of coal in electric generating plants. Fly ash consists of inorganic, incombustible matter present in the coal that has been fused during combustion into a glassy, amorphous structure. Fly ash particles are generally spherical in shape and range in size from 2 μm to 10 μm. They consist mostly of silicon dioxide (SiO2), aluminium oxide (Al2O3) and iron oxide (Fe2O3). Fly ash like soil contains trace concentrations of the following heavy metals: nickel, vanadium, cadmium, barium, chromium, copper, molybdenum, zinc and lead. The chemical compositions of the sample have been examined and the fly ash are of ASTM C618 Class F.
The specimens used were CaCO3 (Sigma Aldrich, purity 99.9 %). We have 23 parameters and 20 iterations, including two theta zero error, scale factor, thermal effect, coefficients for polynomial describing the background; U, V, W and mixing parameters of the profile peak function, lattice constants, positional parameters and overall isotropic temperature factors. Most the samples show that the crystal structure are rhombohedral with lattice constants a = b = 4.981 Å, c = 17.044 Å and space group is R3C. The microstrain (K) and the particle size (V) of CaCO3 ceramic were calculated using 10 the full width at half maximum (FWHM) of diffraction peaks from (0 1 2), (1 0 4), (0 0 6), (1 1 0), (1 1 3), (2 0 2), (0 1 8), (1 1 6), (2 2 1 ), (1 2 2) crystal planes are 2.1 x 10-2 and
362 nm, respectively.
MeSH terms: Calcium Carbonate; Ceramics; Particle Size; Temperature
Ceramic foams are a class of high porosity materials that are used or being considered for a wide range of technological applications. Ceramic foam was produce by polymer replication method. In this process, commercial polymeric sponge was use as template, dipping with ceramic particles slurry, drying and then sintered to yield a replica of the original foams. The study was focus on the fabrication of different density of ceramic foams by varying the density of ceramic slurries (1.1876, 1.2687, 1.3653 and 1.5295 g/cm3). Properties of ceramic foam produced such as density was characterized accordingly to ASTM C 271-94 and porosity were characterized using Archimedes methods. Compressive and bending strength was performed accordingly to ASTM C1161-94 and C773-88 (1999), respectively. The morphological study was performed using Scanning Electron Microscopy (SEM) and EDX. Density of ceramic foams produced was about 0.5588 and 1.1852 g/cm3, where as porosity was around 26.28 and 70.59 %. Compressive and bending strength was increase from strength also increases from 2.60 to 23.07 MPa and 1.20 to 11.10 MPa, respectively, with increasing of slurries density from 1.1876 to 1.3653 g/cm3. The SEM micrographs show that the cells structure become denser as the slurries density increased. EDX proved that the ceramic used is porcelain. As a conclusion, increasing in slurries density produced ceramic foams with good mechanical properties such as compressive and bending strength and denser body.
Sodium silicate was used to synthesize silica fine particles at room temperature using non-ionic surfactant of triethanolamine (TEA), dissolution salt and precipitating agent. The experiments were conducted by different composition of precursor material, nonionic surfactant and dissolution salt concentrations through the sol-gel process. Various particle sizes in the range 100-300nm were synthesized. The particle size of silica powders were analyzed via Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Analysis (EDAX), X-Ray Fluorescence (XRF), and Fourier Transformation Infrared (FTIR). The result has demonstrated that the particle size can be controlled by changing the ratio of non-ionic surfactant and dissolution salt or the sodium silicate concentration.
The storage of oil sludge at refineries is a major problem to the petroleum industry. Oil sludge treatments such as by using sludge farming, incineration, physical and chemical techniques have been applied to separate the hydrocarbon from the solid sediment. The paper relates a characteristic study performed on solid sediment from a local oil sludge sample for making sintered brick. The study includes the used of XRD, XRF, digital microscopy and particle size analyzer. The result shows that the sample highly contains quartz minerals with particle size ranging from 0.5 – 200 ȝm. The chemical phosphorous from the surfactant can be removed by washing to make this solid sediment to be used as a material in the brick making.
MeSH terms: Oil and Gas Industry; Agriculture; Hydrocarbons; Microscopy; Paper; Particle Size; Pulmonary Surfactants; Quartz; Sewage; Surface-Active Agents; Incineration
Alumina powder was synthesized from an aluminum precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was of high purity and highly crystalline D-phase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder.
Hydroxyapatite (HA) powder was synthesized via wet method using calcium nitrate hydrate (Ca(NO3)2.H2O) and diammonium hydrogen phosphate ((NH4)2HPO4) as raw materials. Powder obtained was milled using various milling speed ranging from 250 to 400 r.p.m. and sintered at 1300°C for 2hrs. Due to the nature of HA powder that decomposed at high temperature, XRD technique have been used in this work to determine the phase composition of the HA powder and also the crystallite size. The unmilled sample was used as the control group. Results show that sufficient heat supply generated from the milling process, initiates the decomposition of HA phase into ȕ-tricalcium phosphate (ȕ-TCP). Decomposition of HA starts to occur at the milling speed of 300 rpm, i.e the formation of ȕ-TCP was occurred at lower sintering temperature. It was believed that the decomposition of HA was associated with the formation of an intermediate phase, oxyapatite. Moreover, the crystallinity and particle size of the produced powder is very much affected by the milling speed and the stability of the HA. All milled powders possess spherical shape particle.
MeSH terms: Calcium Phosphates; Cold Temperature; Hot Temperature; Hydroxyapatites; Nitrates; Particle Size; Phosphates; Powders; Temperature; Calcium Compounds; Control Groups
The composite polymer films of polyvinyl alcohol/polypyrrole/chloral hydrate (PVA-PPy-CH) had been prepared. Effects of γ-rays on the electrical conductivity of the composite polymer films had been investigated by using Inductance Capacitance Resistance meter (LCR) meter at a frequency ranging from 20 Hz to 1 MHz. With the incorporation of chloral hydrate in the polymer sample, the conductivity increased indicates that it is capable to be used as dopant for polymerizing conjugated polymer. The electrical conductivity obtained increased as the dose increased, which is in the order of 10-5 Scm-1 indicates that γ-rays is capable to enhance the electrical conductivity of the composite polymer films. The parameter of s is in the range of 0.31 d s d 0.49 and obeyed simple power law dispersion ωs. The Scanning Electron Microscopy (SEM) micrographs reveal the formation of polypyrrole globules in polyvinyl alcohol matrix which increased as the irradiation dose was increased.
The Association of South East Asian Nations (ASEAN) was formed in 1971, and 10 years
later the ASEAN Federation for Psychiatry and Mental Health (AFPMH) was formally
launched. This article reviews the objectives, structure, membership, and the principles of
rotational participation and responsibility of the AFPMH, which has just celebrated its jubilee anniversary last year. Twenty-six years have passed, and the AFPMH has achieved many successes, including the congress, which is currently held every two years, and the ASEAN Journal of Psychiatry, which may be the oldest regional journal in the Asian continent. The bright future of ASEAN psychiatry is expected but relies heavily on the unity and commitment of all individual psychiatric associations within the ASEAN.
MeSH terms: Anniversaries and Special Events; Humans; Mental Health; Psychiatry; Resin Cements; Asian Continental Ancestry Group
Introduction: To date, there are limited published literatures addressing behaviors of Attention Deficit and Hyperactive Disorder (ADHD) children and their parents’ psychological
characteristics. It is also crucial to know the relationship between characteristics of ADHD
behaviors on their parental psychological impacts. Objective: To determine the level of stress, anxiety and depressive among mothers of ADHD children compared to control group and also to determine the associations between domains of children’s behaviors (externalizing or internalizing) that gives most impact to these maternal psychological aspects. Method: This is a cross-sectional study. Seventy mothers of ADHD children who came to Child and Adolescent Clinic, Universiti Kebangsaan Malaysia Hospital completed self-rating questionnaires of Child Behavior Checklist (CBCL), Parenting Stress Index (PSI) and Hospital Anxiety and Depressive Scale (HADS). Seventy mothers of asthmatic children were recruited as a control group. Results: Mothers with ADHD children are more anxious, depressed and stressed (p
MeSH terms: Adolescent; Anxiety; Anxiety Disorders; Attention; Attention Deficit Disorder with Hyperactivity; Child; Child Behavior; Cross-Sectional Studies; Humans; Malaysia; Mothers; Parents; Surveys and Questionnaires; Parenting; Control Groups; Checklist
This is a cross-sectional, two-year follow up study. The authors determined the varied presentations of delirium, dementia and other organic disorders to assess their mortality and outcome. They described the diagnosis of patients suffering from the psychiatric effects of those organic states and compared their symptom resolution and mortality between those with the acute and chronic varieties during their index hospitalization and again, 24 months later. Although mortality rates did not differ, patients with the acute syndrome had significantly better outcomes in terms of symptom resolution as compared to those with the chronic syndrome (p=0.001). Patients with symptom resolution upon discharge did not show statistically significant lower mortality rates.
Objective: To investigate the prevalence of genital arousal disorder and the potential risk
factors that may impair genital arousal among women at a primary care setting in Malaysia.
Methods: A validated questionnaire for sexual function was used to assess genital arousal
function. A total of 230 married women aged 18–70 years old participated in this study. Their sociodemographic and marital profiles were compared between those who had genital arousal disorder and those who did not. The risk factors were examined. Results: The prevalence of genital arousal disorder in the primary care population was 50.4% (116/230). Women with genital arousal disorder were found to be significantly higher in groups of more than 45 years old (p55) (p=.001), those having 4 children or more (p=.028), those having less sexual intercourse (less than 1–2 times a week) (p=.001), and those at post-menopausal state (p=.002). There was no significant difference between these two groups in term of salary (p=.29), suffering from medical problems (p=.32), dysmenorrhea (p=.95), menarche (p=.5) and hormonal replacement therapy (p=.6). Conclusion: Women with infrequent sexual intercourse are less likely to be sexually aroused (OR=0.29, 95% CI: 0.11-0.74).
MeSH terms: Adult; Ambulatory Care Facilities; Arousal; Coitus; Cross-Sectional Studies; Dysmenorrhea; Female; Humans; Malaysia; Primary Health Care; Surveys and Questionnaires; Risk Factors; Sexual Behavior; Prevalence
Objective: This study aimed to determine the prevalence of obesity among patients with schizophrenia and its association with the demographic profile. Methods: This is a cross sectional study. Subjects were selected using systematic sampling. Patients attending the out patient psychiatric clinic, Hospital Universiti Kebangsaan Malaysia, who fulfilled the criteria and able to give consent were included in this study. Diagnosis of schizophrenia was made using Structured Clinical Interview (SCID) for DSM-IV. Demographic profiles of the patients were obtained and anthropometric measurements were measured and classified according to Body Mass Index (BMI) and Waist Circumference (WC) of Asian population. Results: A total of 97 patients were included. The prevalence of overweight (BMI: 23.0- 27.4 kg/m2) was 39.2% (n=38), and the prevalence of obesity (BMI: >27.0 kg/m2) was 35.1% (n=34). BMI was higher among non-Chinese (Malay and Indian, p=.03) and those who had low total household income (p=.03). Sixty-two patients (63.9%) had high WC, which was associated with male (p=.003) and non-Chinese (p=.03). Conclusions: Obesity is highly prevalent among patients with schizophrenia. The risk factors for obesity include male, non-Chinese and those with low total income. The high WC among non-Chinese and male patients suggests that they are at a higher risk of developing obesity-related physical illnesses. These findings support that obesity is a common critical issue among schizophrenic patients, and it warrants serious clinical interventions.
Study site: Psychiatric clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM)
MeSH terms: Cross-Sectional Studies; Hospitals, University; Humans; Malaysia; Male; Obesity; Outpatient Clinics, Hospital; Outpatients; Risk Factors; Schizophrenia; Body Mass Index; Prevalence; Diagnostic and Statistical Manual of Mental Disorders; Asian Continental Ancestry Group; Overweight; Waist Circumference
Background: Up to date, there are handful questionnaires that have been validated in Bahasa Malaysia (BM). This study aimed to translate the Depression Anxiety Stress Scales 21-item (DASS-21) and measure its psychometric properties. Objectives: To determine the construct validity and acceptability of the DASS, BM. Methods: Two forward and backward translations were done in BM in accordance to guideline, and its validation was determined by using confirmatory factor analysis. A total of 263 subjects were selected by systematic random sampling to represent Malaysian population for reliability and validity purposes. Results: The BM DASS-21 had very good Cronbach’s alpha values of .84, .74 and .79, respectively, for depression, anxiety and stress. In addition, it had good factor loading values for most items (.39 to .73). Correlations among scales were between .54 and .68. Conclusions: BM DASS-21 is correctly and adequately translated to Bahasa Malaysia with high psychometric properties. Further studies are required to support these findings.
MeSH terms: Anxiety; Anxiety Disorders; Depression; Depressive Disorder; Factor Analysis, Statistical; Malaysia; Psychometrics; Surveys and Questionnaires; Translations; Reproducibility of Results
Objectives: To determine the best possible programme that suits our local setting, to determine the average dose required, and to determine possible problems that can arise from implementing such a programme locally and how best to address them. Methods: The inclusion criteria were those above 18, a positive urine test, the presence of a supportive carer and willing to engage in the programme. Methadone was initiated and observations relating to dose, adverse events, relationship with carers, work performance, crime and high risk behaviours were monitored for 18 weeks. Results: Two thirds of the 45 subjects completed the trial over the 18 week period. No significant adverse events occurred and improvement in relationship with carers and work performance were noted with reduction in crime and high risk behaviours. Conclusion: Methadone is a safe and effective drug that can be used in the local Malaysian setting.
MeSH terms: Work Performance; Crime; Health Services; Methadone; Monitoring, Physiologic; Risk-Taking; Urinalysis; Caregivers
Objective: This study aimed to determine the association between the personality traits and
social factors with compliance to anti-hypertensive pharmachotherapy. Methods: This cross
sectional study was conducted from 1st of June until 31st of December 2004, which involved
Hospital Universiti Kebangsaan Malaysia Primary Polyclinic in Bandar Tasik Selatan,
Cheras and Salak Polyclinic in Sepang, Selangor. A total of 200 patients who fulfilled all the inclusion criteria, were selected as respondents. This study used the Mini International Neuropsychiatric Interview (M.I.N.I) for the psychiatric diagnoses and personality characteristics were assessed by using Personality Assessment Schedule (PAS) Results: The prevalence rate of non-compliance was 38.5%. Paranoid personality trait (27.3%) was the most common type of personality traits that associated with non-compliance to the medications prescribed. The results of this study revealed a statistically significant difference between drug compliance and age, race, gender and the site where the study was conducted. No association was found between patients’ education level, occupation, income, marital status, family history of hypertension and personality traits and drug compliance. Conclusion: This study suggested that drug compliance among hypertensive patients was influenced by the presence of psychosocial factors. Hence, it is important for medical practitioners to understand these factors and administer treatment more individual.