Failure Analysis of Fan Motor Shafts of a Tunnel Dryer

This article details the analysis of two conducting shafts operating on blowers of a tunnel dryer. A deductive analysis was applied looking toward a successful recognition of root cause(s), where based on knowledge of background, and failure characteristics, multiple hypothesis are exposed that are further confirmed or rejected according to different tests, material analysis or maintenance history. In both shafts, failure arises from inadequate repairing. In order to confirm this, the failure analysis methodology included the following steps: technical review, visual inspection, fractography, penetrating inks, metallography, optic microscopy and stress analysis. Evidence obtained through these techniques indicates a fatigue failure induced by inadequate repairing procedures; therefore, main recommendation is to take the necessary precautions in order to guarantee minimal alterations on shaft geometry or material microstructure.     

Iron oxide amended biosand filters for virus removal

Laboratory studies were performed to determine if the addition of iron oxides throughout biosand filter (BSF) media would increase virus removal due to adsorption. The proposed mechanism is electrostatic adsorption of negatively charged virion particles to positively charged iron oxides formed during the corrosion of zerovalent iron. Initial tests conducted using continuous flow, small-scale glass columns showed high MS2 bacteriophage removal in an iron-amended sand column (5log₁₀) compared to a sand-only column (0.5log₁₀) over 20 pore volumes. Additionally, two experiments with a column containing iron particles revealed 4log₁₀ and 5log₁₀ removal of rotavirus in the presence of 20 mg/L total organic carbon. Full-scale BSFs with iron particles removed >4log₁₀ MS2 for the duration of the experiment (287 days), while BSF with steel wool removed >4log₁₀ MS2 for the first 160 days. Plug flow for the BSF was shown to depend on uniformity between the iron oxide material and sand media grains. The results suggest that the duration of effective virus removal by iron-amended biosand filtration depends on source water conditions and the quantity and composition of iron material added. Overall, this study provides evidence that iron-amended BSFs may advance the field of point-of-use technologies and bring relief to millions of people suffering from waterborne diseases.     

Book reviews

The Housing and Living Environment for Retired people in Australia. edited by Ross Thorne. Sydney: Hale & Iremonger. 1986. pp348 $A 29.95.

The Modern Urban Landscape. by Edward Relph. London: Croom Helm, 1987 pp279. £10.95.

Housing the Homeless. edited by Jon Erickson and Charles Wilhelm New Brunswick, New Jersey: Center for Urban Policy Research, Rutgers University. 1986. pp459. $19.95.

Cities: Special Issue: Shelter and Homelessness. Vol 4 No 1, February 1987. London: Butterworth. pp104.     

Viable Mycobacterium avium ssp. paratuberculosis isolated from calf milk replacer

When advising farmers on how to control Johne's disease in an infected herd, one of the main recommendations is to avoid feeding waste milk to calves and instead feed calf milk replacer (CMR). This advice is based on the assumption that CMR is free of viable Mycobacterium avium ssp. paratuberculosis (MAP) cells, an assumption that has not previously been challenged. We tested commercial CMR products (n = 83) obtained from dairy farms around the United States by the peptide-mediated magnetic separation (PMS)-phage assay, PMS followed by liquid culture (PMS-culture), and direct IS900 quantitative PCR (qPCR). Conventional microbiological analyses for total mesophilic bacterial counts, coliforms, Salmonella, coagulase-negative staphylococci, streptococci, nonhemolytic Corynebacterium spp., and Bacillus spp. were also performed to assess the overall microbiological quality of the CMR. Twenty-six (31.3%) of the 83 CMR samples showed evidence of the presence of MAP. Seventeen (20.5%) tested positive for viable MAP by the PMS-phage assay, with plaque counts ranging from 6 to 1,212 pfu/50 mL of reconstituted CMR (average 248.5 pfu/50 mL). Twelve (14.5%) CMR samples tested positive for viable MAP by PMS-culture; isolates from all 12 of these samples were subsequently confirmed by whole-genome sequencing to be different cattle strains of MAP. Seven (8.4%) CMR samples tested positive for MAP DNA by IS900 qPCR. Four CMR samples tested positive by both PMS-based tests and 5 CMR samples tested positive by IS900 qPCR plus one or other of the PMS-based tests, but only one CMR sample tested positive by all 3 MAP detection tests applied. All conventional microbiology results were within current standards for whole milk powders. A significant association existed between higher total bacterial counts and presence of viable MAP indicated by either of the PMS-based assays. This represents the first published report of the isolation of viable MAP from CMR. Our findings raise concerns about the potential ability of MAP to survive manufacture of dried milk-based products.     

Rank normalization of impact factors will resolve Vanclay’s dilemma with TRIF

The ThomsonReuters impact factor is a viable, widely used and informative measure of journal visibility and frequency of use. It is accurate, transparent and easy to use. It is a live and evolving system, that can broaden its scope and implement new features and methods. Some of Vanclay’s suggestions, like wider use of order statistics, or our suggestion of rank normalization might be implemented by JCR in the future.     

Young infants' generalization of emotional expressions: Effects of familiarity.

From birth, infants are exposed to a wealth of emotional information in their interactions. Much research has been done to investigate the development of emotion perception, and factors influencing that development. The current study investigates the role of familiarity on 3.5-month-old infants' generalization of emotional expressions. Infants were assigned to one of two habituation sequences: in one sequence, infants were visually habituated to parental expressions of happy or sad. At test, infants viewed either a continuation of the habituation sequence, their mother depicting a novel expression, an unfamiliar female depicting the habituated expression, or an unfamiliar female depicting a novel expression. In the second sequence, a new sample of infants was matched to the infants in the first sequence. These infants viewed the same habituation and test sequences, but the actors were unfamiliar to them. Only those infants who viewed their own mothers and fathers during the habituation sequence increased looking. They dishabituated looking to maternal novel expressions, the unfamiliar female's novel expression, and the unfamiliar female depicting the habituated expression, especially when sad parental expressions were followed by an expression change to happy or to a change in person. Infants are guided in their recognition of emotional expressions by the familiarity of their parents, before generalizing to others. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effect of mixed solvents on PCDTBT:PC70BM based solar cells

We investigated the effect of solvents on the morphology, charge transport and device performance of poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C71-butyric acid methyl ester (PC₇₀BM) based solar cells. To carry out this investigation, chloroform and 1,2-dichlorobenzene were chosen as good solvents of the two compounds. Films prepared with chloroform exhibit larger domains than those prepared with 1,2-dichlorobenzene and their size increases with the amount of PC₇₀BM. Fine tuning of the domain size was realized by using a solvent of mixed chloroform and 1,2-dichlorobenzene. At a mixing ratio of 50%:50%, a power conversion efficiency of 6.1% was achieved on PCDTBT:PC₇₀BM (1:3) devices with an active area of 1 cm², under air mass 1.5 global (AM 1.5 G) irradiation at 100 mW/cm².