The load-bearing of composite slabs with steel deck under natural fires

Composite slabs with steel deck combine the load-bearing resistance of the steel deck and rebar with the compressive resistance of the concrete (components). Unprotected composite slabs may be exposed to natural fire conditions from below, and steel reduces its load-bearing capacity during the heating stage. In short fire events, with limited deformations, the composite slabs can recover the load-bearing capacity during the cooling stage. This research presents the validation of the numerical model and the development of a parametric study, to evaluate the load-bearing capacity during the fire event. This method includes a time step procedure, based on the average temperature calculation for each component, including the reduction coefficients applied to the design strength of each material. A new proposal is also presented to evaluate the residual loadbearing capacity. In some circumstances, the residual load-bearing can be reduced by more than 20%. The results showed that the highest variation in the load-bearing resistance of composite slabs occurs when the steel temperatures are between 20 and 600 ℃, after this temperature, the steel has already lost most of its mechanical strength. Moreover, it was observed that different heating rates and different cooling rates influence the rate of the reduction and recovery of the load-bearing capacity. It was also noticed that the lowest load-bearing capacity of the composite slabs was reached after the end of the heating phase, showing that the stability of the element during the heating phase does not guarantee fire safety during the cooling phase.info:eu-repo/semantics/publishedVersio

Laparoscopic Upper-pole Nephroureterectomy In Infants

Objective: Report the results of laparoscopic upper-pole nephroureterectomy in infants. Materials and Methods: Six consecutive infants underwent 7 laparoscopic upper-pole nephroureterectomy. Pre and post-operative evaluation included renal sonography, voiding cystourethrogram and renal scintigraphy. All infants showed upper-pole exclusion. Surgery was performed through a transperitoneal approach with full flank position in all infants. Three or 4 ports were used according to the necessity of retracting the liver. The distal ureter was ligated close to the bladder whenever reflux was present and the dysplastic upper-pole was divided with the help of an electrocautery. Data regarding operative time, postoperative use of analgesics, time to resume oral feeding, hospital stay and tubular function were collected and analyzed. Results: All procedures were concluded as planned. Mean operative time was 135 min. One patient underwent staged bilateral upper-pole nephrectomy. There were no complications and the postoperative hospital stay was 48 hours in 5 procedures and 24 hours in 2 procedures. Pain medication was required only in the first day. Renal tubular function showed improvement in half of the cases. Conclusion: Laparoscopic partial nephrectomy is a safe and feasible procedure in infants. Due to the magnification provided by the lenses, a better vision of the structures is achieved, facilitating selective dissection of vascular upper-pole, renal parenchyma and distal ureter. This approach is less damaging to the lower pole, and is associated to low morbidity and a short hospital stay.3318791Peters, C.A., Laparoscopic and robotic approach to genitourinary anomalies in children (2004) Urol Clin North Am, 31, pp. 595-605Robinson, B.C., Snow, B.W., Cartwright, P.C., De Vries, C.R., Hamilton, B.D., Anderson, J.B., Comparison of laparoscopic versus open partial nephrectomy in a pediatric series (2003) J Urol, 169, pp. 638-640Steyaert, H., Valla, J.S., Minimally invasive urologic surgery in children: An overview of what can be done (2005) Eur J Pediatr Surg, 15, pp. 307-313Koyle, M.A., Woo, H.H., Kavoussi, L.R., Laparoscopic nephrectomy in the first year of life (1993) J Pediatr Surg, 28, pp. 693-695Valla, J.S., Breaud, J., Carfagna, L., Tursini, S., Steyaert, H., Treatment of ureterocele on duplex ureter: Upper pole nephrectomy by retroperitoneoscopy in children based on a series of 24 cases (2003) Eur Urol, 43, pp. 426-429Jordan, G.H., Winslow, B.H., Laparoendoscopic upper pole partial nephrectomy with ureterectomy (1993) J Urol, 150, pp. 940-943Horowitz, M., Shah, S.M., Ferzli, G., Syad, P.I., Glassberg, K.I., Laparoscopic partial upper pole nephrectomy in infants and children (2001) BJU Int, 87, pp. 514-516Gill, I.S., Delworth, M.G., Munch, L.C., Laparoscopic retroperitoneal partial nephrectomy (1994) J Urol, 152, pp. 1539-1542Borzi, P.A., A comparison of the lateral and posterior retroperitoneoscopic approach for complete and partial nephroureterectomy in children (2001) BJU Int, 87, pp. 517-520Desgrandchamps, F., Gossot, D., Jabbour, M.E., Meria, P., Teillac, P., Le Duc, A., A 3 trocar technique for transperitoneal laparoscopic nephrectomy (1999) J Urol, 161, pp. 1530-1532Hulbert, W.C., Rabinowitz, R., Prenatal diagnosis of duplex system hydronephrosis: Effect on renal salvage (1998) Urology, 51, pp. 23-26El-Ghoneimi, A., Farhat, W., Bolduc, S., Bagli, D., McLorie, G., Khoury, A., Retroperitoneal laparoscopic vs open partial nephroureterectomy in children (2003) BJU Int, 91, pp. 532-535Jednak, R., Kryger, J.V., Barthold, J.S., Gonzalez, R., A simplified technique of upper pole heminephrectomy for duplex kidney (2000) J Urol, 164, pp. 1326-1328Borzi, P.A., Yeung, C.K., Selective approach for transperitoneal and extraperitoneal endoscopic nephrectomy in children (2004) J Urol, 171, pp. 814-816Guillonneau, B., Ballanger, P., Lugagne, P.M., Valla, J.S., Vallancien, G., Laparoscopic versus lumboscopic nephrectomy (1996) Eur Urol, 29, pp. 288-291Janetschek, G., Seibold, J., Radmayr, C., Bartsch, G., Laparoscopic heminephroureterectomy in pediatric patients (1997) J Urol, 158, pp. 1928-193

Low temperature behavior of poultry fat biodiesel:diesel blends

AbstractAs the worldwide consumption of poultry meat rises the use of poultry fat as a feedstock for biodiesel production becomes attractive considering economical and environmental reasons. However, poultry fat biodiesel still faces some restrictions due to its poor flow properties at low temperatures. In this study ethylic and methylic poultry fat biodiesels and their blends with diesel were evaluated in terms of flow properties. Modulated Temperature Differential Scanning Calorimetry (MT-DSC) was used to understand the physical meaning of properties as Cold Filter Plugging Point (CFPP), Pour Point (PP) and Cloud Point (CP), widely used in biodiesel characterization. Based on the MT-DSC studies, it was observed that the first crystallization peak temperature had values similar to CFPP and CP. This way CP was found to be associated with the first solidified material and not with the early formation of the first nuclei, as normally reported. On the other hand, these crystals already lead to the flow decrease, as indicate by the CFPP results. PP values were close to the second crystallization peak temperature, not being related to the complete solidification of the fuel

Superinflation, quintessence, and nonsingular cosmologies

The dynamics of a universe dominated by a self-interacting nonminimally coupled scalar field are considered. The structure of the phase space and complete phase portraits are given. New dynamical behaviors include superinflation ($\dot{H}>0$), avoidance of big bang singularities through classical birth of the universe, and spontaneous entry into and exit from inflation. This model is promising for describing quintessence as a nonminimally coupled scalar field.Comment: 4 pages, 2 figure

A Raman Study of Morphotropic Phase Boundary in PbZr1-xTixO3 at low temperatures

Raman spectra of PbZr1-xTixO3 ceramics with titanium concentration varying between 0.40 and 0.60 were measured at 7 K. By observing the concentration-frequency dependence of vibrational modes, we identified the boundaries among rhombohedral, monoclinic, and tetragonal ferroelectric phases. The analysis of the spectra was made in the view of theory group analysis making possible the assignment of some modes for the monoclinic phase.Comment: 5 pages, 4 figure

Sampling procedures for spittlebug adults in pastures of Brachiaria decumbens

Foi conduzido um estudo sobre amostragem de adultos de cigarrinhas em pastagens de Brachiaria decumbens para se determinar o melhor número de batidas em uma amostra de rede entomológica. Considerando-se a variação relativa (EP/X) X 100, e o número total de batidas na amostragem, encontra-se 10 batidas/amostra ser melhor do que 5, 20 ou 40. O número de amostras necessárias para determinado nível de variação relativa nas populações de cigarrinhas > 16 adultos/10 batidas foi o mesmo, ao passo que, nas densidades 16 spittlebug adults/10 sweeps remained the same, whereas at densities < 16, the number increased inversely. A regression model to convert relative estimates obtained by sweep-net method to the absolute estimate was presented. Considering the degree of precision and the time spent in sampling, the sweep-net method was superior to cage method. The distribution pattern of numbers of spittlebug adults in samples of 10 sweep-net sweeps, generally fitted the Poisson series. A sequential plan presented here would reduce the sampling time over the conventional (fixed sample numbers) sampling

Coupled oscillators as models of phantom and scalar field cosmologies

We study a toy model for phantom cosmology recently introduced in the literature and consisting of two oscillators, one of which carries negative kinetic energy. The results are compared with the exact phase space picture obtained for similar dynamical systems describing, respectively, a massive canonical scalar field conformally coupled to the spacetime curvature, and a conformally coupled massive phantom. Finally, the dynamical system describing exactly a minimally coupled phantom is studied and compared with the toy model.Comment: 18 pages, LaTeX, to appear in Physical Review