Fabrication and mechanical testing of a new sandwich structure with carbon fiber network core

The aim is the fabrication and mechanical testing of sandwich structures including a new core material known as fiber network sandwich materials. As fabrication norms for such a material do not exist as such, so the primary goal is to reproduce successfully fiber network sandwich specimens. Enhanced vibration testing diagnoses the quality of the fabrication process. These sandwich materials possess low structural strength as proved by the static tests (compression, bending), but the vibration test results give high damping values, making the material suitable for vibro-acoustic applications where structural strength is of secondary importance e.g., internal panelling of a helicopter

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)

Porous materials for thermal management under extreme conditions

A brief analysis is presented of how heat transfer takes place in porous materials of various types. The emphasis is on materials able to withstand extremes of temperature, gas pressure, irradiation, etc., i.e. metals and ceramics, rather than polymers. A primary aim is commonly to maximize either the thermal resistance (i.e. provide insulation) or the rate of thermal equilibration between the material and a fluid passing through it (i.e. to facilitate heat exchange). The main structural characteristics concern porosity (void content), anisotropy, pore connectivity and scale. The effect of scale is complex, since the permeability decreases as the structure is refined, but the interfacial area for fluid–solid heat exchange is, thereby, raised. The durability of the pore structure may also be an issue, with a possible disadvantage of finer scale structures being poor microstructural stability under service conditions. Finally, good mechanical properties may be required, since the development of thermal gradients, high fluid fluxes, etc. can generate substantial levels of stress. There are, thus, some complex interplays between service conditions, pore architecture/scale, fluid permeation characteristics, convective heat flow, thermal conduction and radiative heat transfer. Such interplays are illustrated with reference to three examples: (i) a thermal barrier coating in a gas turbine engine; (ii) a Space Shuttle tile; and (iii) a Stirling engine heat exchanger. Highly porous, permeable materials are often made by bonding fibres together into a network structure and much of the analysis presented here is oriented towards such materials

Uterine sarcomas: Therapeutic approach, prognostic and epidemiologic factors evaluation: A prospective clinical study of 36 cases

Introduction: The purpose of the present prospective study was to evaluate prognosis (survival, recurrence rates) and other prognostic and epidemiologic factors regarding uterine sarcomas, after the application of a specific therapeutic protocol. Patients or Methods: This protocol included radical cytoreduction surgery and adjuvant chemotherapy with multiple agents (ifosfamide, etoposide, doxorubicin, MESNA). The study included 36 patients with no recessive or progressive disease after surgery. 22 of the cases (61%) were mixed mullerian tumors, 10 (28%) were leiomyosarcomas and 4 (11%) other types. Results: Mean age of appearance was 63.5 years for mixed mullerian tumors, 52.8 for leiomyosarcoma and 38.7 for other types, a difference that was significant (p = 0.008). Additionally, the proportion of premenopausal patients was significantly increased among tumors with other histological types. After a median 61.5 months follow-up, we registered as median survival rate 46.8 months and as median disease free period 29.5 months in total. This clinical outcome is considered as satisfactory, taking in mind the tumors' aggressiveness. Per histological type, median survival rate was 46.8 months for mixed mullerian tumors and 44.1 months for leiomyosarcoma, a difference which was not significant. On the contrary, patients with leiomyosarcoma relapsed more rapidly than patients with mixed mullerian tumors and other types and this difference was significant (p = 0.01).Therefore, the leiomyosarcoma appears to be the most aggressive histologic type among uterine sarcomas. Stage at presentation (early I, II vs. advanced III, IV) was not proved to be of statistical significance regarding survival and recurrence rates, obviously because of the relatively high survival and disease free period rates achieved among advanced stage patients, possibly due to recurrence successful chemotherapy treatment after radical surgery. In mixed mullerian tumors vascular invasion and the presence of heterologous elements does not affect clinical outcome, although we observed a clear tendency for a worse prognosis in the last case. Conclusions: Despite tumor's aggressiveness and low survival and disease free period rates, a complex therapeutic protocol application which includes radical surgical cytoreduction and adjuvant postoperative chemotherapy with multiple therapeutic regiments, may contribute to higher survival and recurrence free rates. Adjuvant radiotherapy doesn't seem to improve clinical outcome. Leiomyosarcoma seems to be the most aggressive histological type among female genital tract sarcomas, since it rapidly relapses. © Georg Thieme Verlag KG Stuttgart

Fracture of open- and closed-cell metal foams

Two closed cell aluminium foams and one open cell nickel-chromium foam were subjected to microstructural characterization, in situ fracture tests and fractography. The failure process of the open cell foam was observed to be rather ductile, while that of the closed cell foams was found to be brittle. The ductility was related to the purity of the nickel chromium alloy, resulting in necking to be the dominant source of energy dissipation during failure. The brittleness of the closed cell foams was related to the presence of precipitates and particles in the cell wall microstructure, limiting the amount of plastic dissipation. The embrittling phases were traced back to the alloy composition, viscosity enhancing additions and foaming agent.