ABSTRACT
This study investigated the dry and aqueous erosion of mild steel using electrochemical and dry sand impact techniques. In dry sand impact experiments, mild steel was eroded with 45 µm and 150 µm sand particles. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and micro-hardness techniques were used to elaborate the surface morphology of the eroded samples. The results revealed significant change in morphology of the eroded samples. In-depth analysis showed that although the metal erosion due to larger particles was significantly higher, the fines also notably damaged the metal surface. The surface damages were appreciably reduced with decrease in impact angle of the accelerated particles. The maximum damages were observed at an impact angle of 90°. The hardness of the samples treated with 45 µm and 150 µm sand remained in the range of 88.34 to 102.31 VHN and 87.7 to 97.55 VHN, respectively. In electrochemical experiments, a triple electrode probe was added into the metal treatment process. The linear polarization resistance (LPR) measurements were performed in slurries having 5% (by weight) of sand particles. LPR of the samples treated with 45 µm and 150 µm sand slurries was calculated about 949 Ω.cm(2) and 809 Ω.cm(2), respectively.
ABSTRACT
Schizophrenia is a chronic psychiatric disorder and pharmacotherapy plays a major role in its management. The 1950s and early 1960s saw milestones in the introduction of psychotropic drugs in clinical practice. A review of drug prescriptions in different settings provides an insight into the pattern of drug use, identifies drug-related problems and may be used to compare recommended guidelines with actual practice. This effort led to the evaluation of the drug prescribing pattern of antipsychotics in patients attending the psychiatric clinic at a government hospital. The data from 371 antipsychotic medication prescriptions that included 200 prescriptions for schizophrenia were collected during one month (1rst-31rst August 2008) at the outpatient pharmacy department. The mean age of patients was 35.0 years (SD = 1.131), with a male to female ratio of 2:1. The most widely used oral antipsychotic was haloperidol (16.3%) while the most common depot preparation prescribed was zuclopenthixol decanoate (8.8%). The daily dose of the average antipsychotic prescribed in this clinic was 342.06 mg equivalent of chlorpromazine. There was no relation between the doses received and ethnicity of the patient (Malay, Chinese or Indian). However, there was a significant relationship between the prescribed dose and patient age (P < 0.042). Nearly 32% of the schizophrenia patients were prescribed with atypical antipsychotics such as olanzapine (10.8%), risperidone (10.0%), quetiapine (7.6%) and clozapine (3.2%). Monotherapy was given to 73.0% of the schizophrenia patients. The majority of patients also received antidepressants. To conclude, this study gave evidence that physicians had a strong preference for monotherapy with conventional antipsychotic drugs while the use of atypical drugs was less prevalent.
