Quantitative Risk Assessment (QRA) nowadays is an established risk assessment method used worldwide for the evaluation of risks on onshore plant and offshore facilities which associated with the major hazard installations. However, there are still many issues on QRA used. These include lack of consistency, complexity of the overall model structure, incorporation of new data, methodology and model analysis. Common problem observed for the onshore QRA methodology is conservatism of fire and explosion consequence results using DNV PhastRisk 6.7 software which is mainly contributed from the high release rate due to loss of containment. This paper presents an alternative way to predict the actual release rate for fire and explosion modelling which called limiting flowrate technique. This method has been applied for calculating risk in Onshore Gas Terminal (OGT) Plant. Adopting the limiting flowrate technique has provide more precise model towards real scenarios. Challenges facing during this research such as using the unmodified United Kingdom (UK) HSE hydrocarbon release database without integrate with the actual failure frequencies from the plant, the risk results tend to be much higher than actual experience. It should be noted that the development of improved onshore risk model has been used as an example for this research but many of the issues are equally applicable to offshore studies as well.
Company A is a brownfield refinery that had been in service for over 25 years and has its own system to generate GOX for its needed utility usage. Noting of the hazards of GOX and in consideration of an aged refinery, this research is of the intent to evaluate the risk of GOX in the aspect of personnel and process safety; and to provide recommendation or mitigations planning with regards to Company A’s existing hardware through Bow Tie review. The analysis was done taking into consideration the data compiled as well as the inherited Process Safety Assessment (PSA) findings of Company A that served as secondary data to this research. It was observed that Company A personnel are well versed with the risk and hazards of GOX system and through the plant rejuvenation and material upgrade works, the hazards were mitigated to a lower risk within the risk matrix. The implementation and upgrade works had served to add more barriers to the left side of the bow tie as well as ensuring that the aged complex is well equipped with needed safeguarding strategies (from inherent safer design, passive & active safeguarding and procedural controls) to avoid the occurrence of potential oxygen fire or explosion incident.
Timber is one of the most sustainable and renewable raw materials available. Globally, it has been increasingly used for the manufacture of home and workplace furniture. Timber products are known to have ignition resistance and a low heat release rate. These characteristics delay burning and maintain the structural durability of a product, protecting both the occupants and their properties in a fire. Timber, however, experiences thermal degradation during combustion, yielding smoke, heat, toxic gases, and char when burned. To understand the fire conduct of timber, extensive knowledge in its process of decomposition is essential. This paper, therefore, reviewed the methods of flammability tests widely employed to investigate the reaction of timber and timber-based product to fire, namely cone calorimeter test, room-corner test, limiting oxygen index (LOI) test, furnace test, and single burning item test (SBI). In addition, an overview of the fire retardant treatments; impregnation and coatings was also presented. The potential effects of fire retardants on the durability, strength, hygroscopicity, corrosion, machinability, glueing characteristics, and paintability of the timber were also highlighted.
The present work investigated the antioxidant properties and antihypertensive activity of
magnesium orotate (MgOr) using various established in vitro assays, such as β-carotene
bleaching activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and nitric oxide scavenging activity as well as angiotensin converting enzyme (ACE) inhibitory activity. Magnesium orotate
nanoparticles (MgOrGANPs) were prepared using the gum arabic (GA) as stabiliser coatings
for nanoparticles through freeze-drying method. The in vitro cytoxicity of MgOrGANPs
against human breast cancer MCF7, liver cancer HepG2, and colon cancer HT29 was investigated. The nitric oxide (NO) and DPPH scavenging assays of MgOrGANPs showed a
dose-dependent trend, while 500 and 200 µL/mL were significantly more effective than the
other concentrations with an IC50 of 89.56 µg/mL and 63.22% DPPH scavenging capacity
respectively. The exposure of human cancer cells to MgOrGANPs at 1.56 – 1,000 µg/mL
using 3-)4,5-dimethylthiazol-2-yl(2,5-diphenyl tetrazolium bromide (MTT) inhibited the
growth of cell lines examined in a dose-dependent manner. Hence, MgOrGANPs may have
great potential to be applied for cancer treatments.
The information on the combustion properties of local timber is crucial in Malaysia as the archival material related to this subject matter is found to be very limited in scope and incomplete. The heat release rate (HRR) is the most precious variable of combustion properties as it provides the key to understand and quantify the hazard in fires. Thus, this work is to verify the reliability of the HRR obtained from cone calorimeter tests conducted upon six Malaysian wood species: Shorea laevis, Vatica rassak, Koompassia malaccensis, Heritiera, Shorea parvifolia and Cratoxylum arborescens. The single factor one-way analysis of variance (ANOVA) was used to investigate statistically significant differences between the means of the HRR dataset of each species during the combustion tests at three different heat fluxes. Later, the confidence interval estimation was occupied to determine the range around the HRR dataset, where the means of the data was likely to be found. The intraclass correlation coefficient (ICC) test was also implemented to assess the reliability of the heat release rate data obtained from the cone calorimeter test. From the surveillance, the P-values of all the six species were higher than α = 0.05, insinuating that the difference between the means of the dataset was not statistically significant. The confidence interval values consisting of the upper bound and lower bound limits indicate that the certainty that these ranges contain the true mean of the heat release rate dataset is 95%. Finally, the fact that heat release data received from the cone calorimeter test were highly reliable to statistically calculate the variation in measurements taken by a single instrument under the same condition confirmed by the ICC’s values of 0.82 to 0.99 that reflect good to excellent correlations.
Numerical studies of blood flow system of aorta coronary sinus conduit were carried out using ANSYSTMCFD simulation. A different model of conduit, which differs in the inlet diameter, was investigated. Theinvestigated inlet diameters are 3 mm, 4 mm and 5 mm. Pressure drop from 80 mmHg to 15 mmHgwas achieved for all the models. The comparison chart was produced to compare the pattern of pressurereduction as well as velocity distribution in each model. From the analysis of coronary sinus conduit,it was found that a narrow tube needs to be incorporated into the conduit produced. This is to inducea venturi effect to reduce the pressure drop of blood within a specific throat length. As conclusion, amodel of 3 mm inlet and a throat diameter of 1.13 mm show satisfactory result for pressure reductionfrom 80 mmHg to 15 mmHg. This particular model also has a lower peak velocity at the inlet zone ofthe throat section, which is more preferable in terms of Reynolds number.