Direct numerical simulation of secondary flow in straight ducts forced by non-homogenous force

Turbulent flow in ducts of rectangular section presents secondary flows due to the presence of turbulence. In this work we study this kind of turbulent flow driven by a non-uniform force in the vertical direction. This kind of forcing is used to model the stratification effect over the driving force of the flow. Of particular interest to this work are gravity currents, which are stratified flows generated by the gravity action over relatively small differences in density between two fluids. The fact that the flow is forced by the action of gravity on the density profiles causes the stratification effects to appear on two very different scales. On the microscopic scale stratification modulates turbulence and on the macroscopic scale stratification modulates the driving force of the flow. The objective of this work is to analyze separately the macroscopic effect of stratification inhibiting completely the microscopic effect of stratification. In this work, variations produced on secondary flow of the second kind when the flow is driven by forces that vary linearly and exponentially in the vertical direction are analyzed. These results are compared with the case of flow driven by an uniform force in the vertical direction. To this aim fully resolved direct numeric simulations are performed with a pseudo-spectral code.Publicado en: Mecánica Computacional vol. XXXV, no. 16.Facultad de Ingenierí

Direct numerical simulation of secondary flow in straight ducts forced by non-homogenous force

Turbulent flow in ducts of rectangular section presents secondary flows due to the presence of turbulence. In this work we study this kind of turbulent flow driven by a non-uniform force in the vertical direction. This kind of forcing is used to model the stratification effect over the driving force of the flow. Of particular interest to this work are gravity currents, which are stratified flows generated by the gravity action over relatively small differences in density between two fluids. The fact that the flow is forced by the action of gravity on the density profiles causes the stratification effects to appear on two very different scales. On the microscopic scale stratification modulates turbulence and on the macroscopic scale stratification modulates the driving force of the flow. The objective of this work is to analyze separately the macroscopic effect of stratification inhibiting completely the microscopic effect of stratification. In this work, variations produced on secondary flow of the second kind when the flow is driven by forces that vary linearly and exponentially in the vertical direction are analyzed. These results are compared with the case of flow driven by an uniform force in the vertical direction. To this aim fully resolved direct numeric simulations are performed with a pseudo-spectral code.Publicado en: Mecánica Computacional vol. XXXV, no. 16.Facultad de Ingenierí

Direct numerical simulation of secondary flow in straight ducts forced by non-homogenous force

Turbulent flow in ducts of rectangular section presents secondary flows due to the presence of turbulence. In this work we study this kind of turbulent flow driven by a non-uniform force in the vertical direction. This kind of forcing is used to model the stratification effect over the driving force of the flow. Of particular interest to this work are gravity currents, which are stratified flows generated by the gravity action over relatively small differences in density between two fluids. The fact that the flow is forced by the action of gravity on the density profiles causes the stratification effects to appear on two very different scales. On the microscopic scale stratification modulates turbulence and on the macroscopic scale stratification modulates the driving force of the flow. The objective of this work is to analyze separately the macroscopic effect of stratification inhibiting completely the microscopic effect of stratification. In this work, variations produced on secondary flow of the second kind when the flow is driven by forces that vary linearly and exponentially in the vertical direction are analyzed. These results are compared with the case of flow driven by an uniform force in the vertical direction. To this aim fully resolved direct numeric simulations are performed with a pseudo-spectral code.Publicado en: Mecánica Computacional vol. XXXV, no. 16.Facultad de Ingenierí

Microcephaly and macrocephaly. A study on anthropometric and clinical data from 308 subjects

Head circumference is the auxological parameter that most correlates with developmental anomalies in childhood. Head circumference (HC) two standard deviations (SD) below or above the mean defines microcephaly and macrocephaly, respectively. The aim of this retrospective study was to explore anthropometric parameters and clinical characteristics among subjects with abnormalities in HC who had been referred for developmental assessment. One hundred and sixty four subjects with microcephaly and 144 subjects with macrocephaly were enrolled from birth to 18 months of age. Head circumference at birth and the association with variables related to maternal health status, gestational age, growth pattern, brain imaging and clinical characteristics were analyzed. In some cases, an etiological diagnosis was made. In the two considered conditions, we found different anthropometric and clinical associations, some of which were statistically significant, with implications for ongoing neurodevelopmental surveillance

FEM Analysis: A Review of the Most Common Thermal Bridges and Their Mitigation

The necessity to improve the energy saving potential of buildings is now a duty. European and national policies are being implemented to address the important decisions being made on this subject. For these reasons, several studies focus on this relevant topic. This paper review not only focusses on it but studies it in-depth. A commercial 3D simulation software was used to design a building sited in Palermo estimating the thermal losses before and after external envelope insulation. In particular, all the thermal bridges (TBs) were analysed with the finite element method (FEM) and mitigated with rock wool insulation. The paper shows the linear thermal transmittance difference and heat flux loss before and after TB mitigation. The results confirm the importance of installing an external insulation layer in the old building envelope. The linear thermal transmittance of TBs and the associated heat flux loss often decrease by more than 50%

TTF-1/p63-positive poorly differentiated NSCLC: A histogenetic hypothesis from the basal reserve cell of the terminal respiratory unit

TTF-1 is expressed in the alveolar epithelium and in the basal cells of distal terminal bronchioles. It is considered the most sensitive and specific marker to define the adenocarcinoma arising from the terminal respiratory unit (TRU). TTF-1, CK7, CK5/6, p63 and p40 are useful for typifying the majority of non-small-cell lung cancers, with TTF and CK7 being typically expressed in adenocarcinomas and the latter three being expressed in squamous cell carcinoma. As tumors with coexpression of both TTF-1 and p63 in the same cells are rare, we describe different cases that coexpress them, suggesting a histogenetic hypothesis of their origin. We report 10 cases of poorly differentiated non-small-cell lung carcinoma (PD-NSCLC). Immunohistochemistry was performed by using TTF-1, p63, p40 (∆Np63), CK5/6 and CK7. EGFR and BRAF gene mutational analysis was performed by using real-time PCR. All the cases showed coexpression of p63 and TTF-1. Six of them showing CK7+ and CK5/6− immunostaining were diagnosed as “TTF-1+ p63+ adenocarcinoma”. The other cases of PD-NSCLC, despite the positivity for CK5/6, were diagnosed as “adenocarcinoma, solid variant”, in keeping with the presence of TTF-1 expression and p40 negativity. A “wild type” genotype of EGFR was evidenced in all cases. TTF1 stained positively the alveolar epithelium and the basal reserve cells of TRU, with the latter also being positive for p63. The coexpression of p63 and TTF-1 could suggest the origin from the basal reserve cells of TRU and represent the capability to differentiate towards different histogenetic lines. More aggressive clinical and morphological features could characterize these “basal-type tumors” like those in the better known “basal-like” cancer of the breast

Individuals’ Decision to Co-Donate or Donate Alone: An Archival Study of Married Whole Body Donors in Hawaii

Human cadavers are crucial to numerous aspects of health care, including initial and continuing training of medical doctors and advancement of medical research. Concerns have periodically been raised about the limited number of whole body donations. Little is known, however, about a unique form of donation, namely co-donations or instances when married individuals decide to register at the same time as their spouse as whole body donors. Our study aims to determine the extent of whole body co-donation and individual factors that might influence co-donation. Methods and Findings: We reviewed all records of registrants to the University of Hawaii Medical School's whole body donation program from 1967 through 2006 to identify married registrants. We then examined the 806 married individuals' characteristics to understand their decision to register alone or with their spouse. We found that married individuals who registered at the same time as their spouse accounted for 38.2 percent of married registrants. Sex differences provided an initial lens to understand co-donation. Wives were more likely to co-donate than to register alone (p = 0.002). Moreover, registrants' main occupational background had a significant effect on co-donations (p = 0.001). Married registrants (regardless of sex) in female-gendered occupations were more likely to co-donate than to donate alone (p = 0.014). Female-gendered occupations were defined as ones in which women represented more than 55 percent of the workforce (e.g., preschool teachers). Thus, variations in donors' occupational backgrounds explained co-donation above and beyond sex differences. Conclusions: Efforts to secure whole body donations have historically focused on individual donations regardless of donors' marital status. More attention needs to be paid, however, to co-donations since they represent a non-trivial number of total donations. Also, targeted outreach efforts to male and female members of female-gendered occupations might prove a successful way to increase donations through co-donations