Efficient Design of Thin Wall Seating Made of a Single Piece of Heavy-Duty Corrugated Cardboard.

Corrugated cardboard has waved cores with small flutes that prevent the use of detailed numerical models of whole structures. Many homogenization methods in the literature overcome this drawback by defining equivalent homogeneous plates with the same mechanical behaviour at a macro-mechanical scale. However, few homogenization works have considered complete structures, focusing mainly on beams or plates. For the first time, this study explores the application of homogenization approaches to larger structures as an aid in their design process. We also considered triple-wall boards rather than single- and double-wall configurations commonly addressed in the literature. To this end, we adapted the homogenization methods proposed by Talbi and Duong to analyze thin-walled stools made of triple-wall corrugated cardboard. Using a progressive design process, we performed an efficient stool design by removing material zones with lower stresses, with 35% less material, 35% lower vertical deflections, and 66% lower stresses than the initial design. Unlike other corrugated cardboard stools, this design comprises just one folded piece instead of three, thus saving storage space. These results demonstrate the utility of homogenization techniques as an aid in the design process of whole structures made of corrugated cardboard. Further research will consider buckling analysis.

Enhancing the Accuracy of Linear Finite Element Models of Vehicle Structures Considering Spot-Welded Flanges.

Structural engineering simulations have required increasingly complex computational models to replace physical tests accurately. This work focuses on the numerical analysis of vehicle body structures, whose size and complexity make the use of very accurate nonlinear models unfeasible due to the prohibitive computational costs involved. The purpose of this study is to find a new approach to model spot-welded joints in linear finite element models of thin-wall vehicle body structures, improving the accuracy of the model without increasing its complexity. Using a set of simplified nonlinear models, we fitted the stiffness and damping properties of these welded joints and used those adjusted values into a linear model of the entire vehicle body structure. The results were compared with experimental tests, showing a clear improvement in the accuracy of the modal and frequency responses provided by the linear finite element model, but keeping its initial complexity level. The adjusted model was then used in an optimization analysis to reduce the structure's weight, leading to interesting cost savings and important reductions in the use of natural resources and carbon emissions.

Phlebovirus-associated diseases transmitted by phlebotominae in Spain: Are we at risk?

The genera Phlebovirus transmitted by Diptera belonging to the Psychodidae family are a cause of self-limited febrile syndrome in the Mediterranean basin in summer and autumn. Toscana virus can also cause meningitis and meningoencephalitis. In Spain, Toscana, Granada, Naples, Sicily, Arbia and Arrabida-like viruses have been detected. The almost widespread distribution of Phlebotomus genus vectors, and especially Phlebotomus perniciosus, in which several of these viruses have been detected, makes it very likely that there will be regular human infections in our country, with this risk considered moderate for Toscana virus and low for the other ones, in areas with the highest vector activity. Most of the infections would be undiagnosed, while only Toscana virus would have a greater impact due to the potential severity of the illness.

Occupation and skin cancer: the results of the HELIOS-I multicenter case-control study.

BACKGROUND: Non-melanoma skin cancer (NMSC) is the most frequent tumour among Caucasian populations worldwide. Among the risk factors associated with this tumour, there are host-related factors and several environmental agents. A greater likelihood of high exposure to physical agents (with the exception of solar radiation) and chemical agents depends on the work setting. Our objective is to evaluate the role of occupational exposures in NMSC, with special emphasis on risk factors other than solar radiation and skin type. METHODS: We analysed 1585 cases (1333 basal cell carcinoma (BCC) and 183 squamous cell carcinoma (SCC)) and 1507 controls drawn from the Helios-I multicenter study. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression mixed models. RESULTS: For NMSC as a whole (both histological types), miners and quarrymen, secondary education teachers, and masons registered excess risk, regardless of exposure to solar radiation and skin type (OR 7.04, 95% CI 2.44-20.31; OR 1.75, 95% CI 1.05-2.89 and OR 1.54, 95% CI 1.04-2.27, respectively). Frequency of BCC proved higher among railway engine drivers and firemen (OR 4.55; 95% CI 0.96-21.57), specialised farmers (OR 1.65; 95% CI 1.05-2.59) and salesmen (OR 3.02; 95% CI 1.05-2.86), in addition to miners and quarrymen and secondary education teachers (OR 7.96; 95% CI 2.72-23.23 and OR 1.76; 95% CI 1.05-2.94 respectively). The occupations that registered a higher risk of SCC (though not of BCC) were those involving direct contact with livestock, construction workers not elsewhere classified (OR 2.95, 95% CI 1.12-7.74), stationary engine and related equipment operators not elsewhere classified (OR 5.31, 95% CI 1.13-21.04) and masons (OR 2.55, 95% CI 1.36-4.78). CONCLUSION: Exposure to hazardous air pollutants, arsenic, ionizing radiations and burns may explain a good part of the associations observed in this study. The Helios study affords an excellent opportunity for further in-depth study of physical and chemical agents and NMSC based on matrices of occupational exposure.

Association between health information, use of protective devices and occurrence of acute health problems in the Prestige oil spill clean-up in Asturias and Cantabria (Spain): a cross-sectional study.

BACKGROUND: This paper examines the association between use of protective devices, frequency of acute health problems and health-protection information received by participants engaged in the Prestige oil spill clean-up in Asturias and Cantabria, Spain. METHODS: We studied 133 seamen, 135 bird cleaners, 266 volunteers and 265 paid workers selected by random sampling, stratified by type of worker and number of working days. Information was collected by telephone interview conducted in June 2003. The association of interest was summarized, using odds ratios (OR) obtained from logistic regression. RESULTS: Health-protection briefing was associated with use of protective devices and clothing. Uninformed subjects registered a significant excess risk of itchy eyes (OR:2.89; 95%CI:1.21-6.90), nausea/vomiting/dizziness (OR:2.25; 95%CI:1.17-4.32) and throat and respiratory problems (OR:2.30; 95%CI:1.15-4.61). There was a noteworthy significant excess risk of headaches (OR:3.86: 95%CI:1.74-8.54) and respiratory problems (OR:2.43; 95%CI:1.02-5.79) among uninformed paid workers. Seamen, the group most exposed to the fuel-oil, were the worst informed and registered the highest frequency of toxicological problems. CONCLUSION: Proper health-protection briefing was associated with greater use of protective devices and lower frequency of health problems. Among seamen, however, the results indicate poorer dissemination of information and the need of specific guidelines for removing fuel-oil at sea.

Accuracy of cancer death certificates in Spain: a summary of available information.

OBJECTIVES: Differences in mortality rates within Europe might be partly due to the quality of mortality statistics. The present article summarizes the available data on the quality of cancer death certification in Spain. A short description of the temporal distribution of the proportion of deaths due to ill-defined tumors in Spain -an indirect indicator of the quality of cancer death certification- is also provided. METHODS: Relevant studies were identified from electronic databases (MEDLINE, EMBASE, IME and IBECS) and from manual searches of the references contained in the articles retrieved. Quality data on death certificates for all tumors and for each specific cancer location were summarized, and all main cancer sites were classified according to their pooled accuracy indicators. Trends for the percentage of deaths due to ill-defined tumors and conditions were studied for the period from 1980 to 2002. RESULTS: In Spain, deaths from cancer as a whole and leading cancer sites (lung, colon-rectum, prostate, stomach, pancreas, female breast, uterus, brain, leukemia, lymphomas and myeloma) were well-certified. However, other frequent locations, such as the larynx, esophagus and liver were overcertified, while deaths from bladder, kidney and ovarian cancer were undercertified. The percentage of deaths due to ill-defined tumors and causes was regularly higher in females and decreased in both sexes during the study period. However, the recent introduction of the International Classification of Diseases (ICD)-10 has reversed this trend. CONCLUSIONS: Spanish death certificates can be considered as accurate and useful to estimate the burden of cancer, though certification of some frequent sites should be improved. The possible effect of the introduction of the ICD-10 requires careful surveillance.

Occupation and thyroid cancer risk in Sweden.

OBJECTIVE: The objective of this study was to identify occupations and industries with increased incidence of thyroid cancer in Swedish workers. METHOD: Standardized incidence ratios were computed for each job and industry for the period 1971-1989 through record-linkage with the Swedish National Cancer and Death Registers. Age-, period-, geographically adjusted relative risks were calculated using Poisson models. RESULTS: Increased risks were found for teachers, construction carpenters, policemen, and prison/reformatory officials in men, and medical technicians, shop managers, tailors, and shoecutters among women. Industries with risk excess are manufacture of agricultural machinery, manufacture of computing/accessories, and public administration/police among men; and manufacture of prefabricated wooden buildings, electric installation work, and wholesale of live animals/fertilizers/oilseed/grain among women. CONCLUSIONS: Our results corroborate some previously reported increased risks. Further research is needed to assess the influence of specific chemical agents related with some of the highlighted work environments.