Effects of Raschig Ring Packing Patterns on Pressure Drop, Heat Transfer, Methane Conversion, and Coke Deposition on a Semi-pilot-scale Packed Bed Reformer

The effects of Raschig ring packing patterns on the efficiency of dry methane reforming reactions were investigated using computational fluid dynamics (CFD). The present study aims to understand the behavior of fluid flow in packed bed reactors, especially under low reactor-to-ring ratios between 4 and 8. Three packing patterns were studied: vertical staggered (VS), chessboard staggered (CS), and reciprocal staggered (RS). It was determined that packing pattern notably affected pressure drop across the reactor length. The VS pattern produced the lowest pressure drop of 223 mPa, while the CS and RS patterns produced pressure drops of 228 mPa and 308 mPa, respectively. The values of methane conversion can be increased by ca. 2 % by selecting a more suitable packing pattern (i.e., 76 % for the VS pattern and 74 % for the CS and RS patterns). This work is licensed under a Creative Commons Attribution 4.0 International License

Tracking virus outbreaks in the twenty-first century

Emerging viruses have the potential to impose substantial mortality, morbidity and economic burdens on human populations. Tracking the spread of infectious diseases to assist in their control has traditionally relied on the analysis of case data gathered as the outbreak proceeds. Here, we describe how many of the key questions in infectious disease epidemiology, from the initial detection and characterization of outbreak viruses, to transmission chain tracking and outbreak mapping, can now be much more accurately addressed using recent advances in virus sequencing and phylogenetics. We highlight the utility of this approach with the hypothetical outbreak of an unknown pathogen, 'Disease X', suggested by the World Health Organization to be a potential cause of a future major epidemic. We also outline the requirements and challenges, including the need for flexible platforms that generate sequence data in real-time, and for these data to be shared as widely and openly as possible

Liver cancer in Thailand. II. A case-control study of hepatocellular carcinoma

Potential risk factors for hepatocellular carcinoma were investigated in a case-control study among inhabitants of north east Thailand. Sixty-five cases from 3 hospitals, with matched controls, were included. Infection with hepatitis-B virus was the major risk factor—chronic carriers of HB surface antigen had an estimated relative risk of 15.2. Infection with hepatltis-C virus appeared to be rare. No increase In risk was found with recent aflatoxin intake, as estimated by consumption of possibly contaminated foods, or by measuring aflatoxin-albumln adducts in serum. Regular use of alcohol (2 or more glasses of spirits per week) was associated with a nonsignificant elevation in risk (o.r. = 3.4, 95% c.i. 0.8–14.6), but the number of regular drinkers in the population was small. The meaning of an apparent protection conferred by certain food items is uncertain, but a possible role of betel nut in the aetiology deserves further investigation

Liver cancer in Thailand. I. A case-control study of cholangiocarcinoma

Potential risk factors for cholangiocarcinoma were investigated in a case-control study among inhabitants of north-east Thailand, which included 103 cases from 3 hospitals, with age-and sex-matched controls. A clear association with past or present infection with Opisthorchis viverrini, as indicated by raised serum antibodies, was found (o.r. 5.0), and at least two-thirds of cases can be attributed to this cause. The results suggest that males may be at higher risk than females. There was no association with hepatitis B infection, with aflatoxin Intake as estimated from albumin adducts in serum or with any particular dietary patterns. Alcohol consumption was very low in the population, and the risk associated with regular drinking was non-significant. Regular users of betel nut—predominantly female—had a high risk (o.r. 6.4), a possible mechanism being through their increased exposure to nitro-samines