Mechanical behaviour of a syntactic foam/glass fibre composite sandwich: experimental results

Papa, Enrico,Corigliano, Alberto,Rizzi, Egidio Techno-Press 2001 Structural Engineering and Mechanics, An Int'l Jou Vol.12 No.2

This note presents the main results of an experimental investigation into the mechanical behaviour of a composite sandwich conceived as a lightweight material for naval engineering applications. The sandwich structure is formed by a three-dimensional glass fibre/polymer matrix fabric with transverse piles interconnecting the skins; the core is filled with a polymer matrix/glass microspheres syntactic foam; additional Glass Fibre Reinforced Plastics extra-skins are laminated on the external facings of the filled fabric. The main features of the experimental tests on syntactic foam, skins and sandwich panels are presented and discussed, with focus on both in-plane and out-of-plane responses. This work is part of a broader research investigation aimed at a complete characterisation, both experimental and numerical, of the complex mechanical behaviour of this composite sandwich.

Effects of Crack Width on Chloride Penetration and Performance Deterioration of RC Columns with Sustained Eccentric Compressive Load

Papa Niane Faye,Yinghua Ye,Bo Diao 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

In a marine environment, the mechanical performance of Reinforced Concrete (RC) structures deteriorates mainly due to the coupling action of service load and/or the corrosion of steel bars. Here, the working conditions of RC columns in a marine environment were simulated in the laboratory. The chloride penetration and performance deterioration of RC columns with different widths for the maximum initial crack of 0, 50, 100 and 200 microns, induced by different levels of external sustained eccentric compressive load and environments of chloride corrosion, were simulated by seawater wet-dry cycles. The results showed that the yielding load and ultimate load of the RC column specimens were significantly decreased as the width of the initial cracks increased. Tensile strain and crack width were both parameters contributing to chloride penetration in the tensile area of the RC column specimens. During the seawater wet-dry cycles, the initial cracks on the column specimens changed. The initial cracks tended to vanish due to the self-healing capacity of concrete when the width of the initial crack was smaller than 50 microns. The initial cracks remained relatively constant when the crack widths were between 50 and 100 microns, and the crack widths increased when the initial crack width was larger than 100 microns.

LES REFORMES DE L’ADMINISTRATION SENEGALAISE

Papa Cambel FALL(파파 캄벨 폴) 서울행정학회 2013 서울행정학회 학술대회 발표논문집 Vol.2013 No.10

How should ecohazard of micropollutants in wastewater be gauged? Using bioassays to profile alternative tertiary treatments

Matteo Papa,Lidia Paredes,Donatella Feretti,Gaia Viola,Giovanna Mazzoleni,Nathalie Steimberg,Roberta Pedrazzani,Juan Lema,Francisco Omil,Marta Carballa 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.3

The research on emerging pollutants in wastewater has become a worldwide issue of increasing environmental concern, especially considering the growing interest in wastewater reuse. However, the latter implies additional post-treatment after the conventional activated sludge processes, in order to produce a safer effluent. Our work aimed at determining the efficiency of reducing the toxicity associated with organic micropollutants (OMPs) in secondary wastewater effluents, using 3 different post-treatment technologies (granular activated carbon (GAC), sand biofiltration and UV irradiation): in particular, target chemical analysis of the OMPs most commonly founded in wastewater was coupled with effect-based assays (estrogenicity and mutagenicity). While chemical analysis assessed satisfactory performances for all 3 technologies in the abatement of selected OMPs, biological assays evidenced another perspective: both GAC and sand biofilters were significantly able to make the estrogenic load plummet; however, the UV system was ineffective in estrogenicity abatement, and its effluent exhibited also a slight mutagenicity, likely due to photo-transformation by-products. These results indicate that a synergistic combination of chemical analysis and biological assays can drive to a proper gauging of post-treatment technologies, taking into account not only the removal of OMPs, but also their overall toxicity.

Atypical Presentation of Acetylcholinesterase Inhibitor-Induced Diarrhea in Older Adults with Cognitive Decline: An Aspect not to be Underestimated

Raffaele Pagliuca,Mario Virgilio Papa,Pagliuca Mena Ilaria,Virginia Federica Papa,Gina Varricchio 대한노인병학회 2023 Annals of geriatric medicine and research Vol.27 No.1

The rivastigmine patch is the only existing transdermal delivery system used for the treatment of Alzheimer disease. Among the most common adverse events derived from its use are gastrointestinal events, particularly diarrhea. We report a clinical case of an 81-year-old patient admitted to our hospital under long-standing treatment with rivastigmine transdermal patch who presented with atypical watery diarrhea. Anamnesis showed that the patient presented with a likely infectious gastroenteric event, the diarrheal symptoms of which persisted upon resolution of the event and resolved only upon temporary discontinuation of acetylcholinesterase inhibitors. Failure to rapidly identify the causes of profuse diarrhea in older adults can have lethal consequences. When these symptoms occur, quickly recognizing the causes and providing proper management can be lifesaving.

A finite element approach in estimating driver fatality ratio of a fleet of LTVs striking a passenger car based on vehicle’s intrusion, acceleration and stiffness ratios in side-impact accidents

Y. Y. Tay,A. Papa,L. S. Koneru,R. Moradi,H. M. Lankarani 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.3

The driver fatality ratio (DFR) proposed by the National Highway Traffic Safety Administration (NHTSA) demonstrates the relativefatality risks of occupants in various vehicle-to-vehicle (VtV) crashes. The readily available DFR is based on statistical crash data; hence,estimating the DFR of occupants for newer fleet of vehicles can be quite difficult. Three systematic methods such as the intrusion, decelerationand stiffness ratios of two colliding vehicles in side-impact accidents are proposed to estimate the DFR. A fleet of light trucks andvans (LTVs) striking a sedan car is reconstructed using the non-linear explicit code, LS-DYNA. The simulation results have shown thatthe intrusion and acceleration ratios-based approaches are in good agreement with the statistical DFR, whereas the DFR estimated usingthe stiffness-ratio based approach yielded poor agreement. The intrusion and acceleration ratios-based approaches are then utilized toformulate a combined DFR estimation model. In the second part of the study, the proposed methodology is carried further to estimate theDFR of occupants for a fleet of LTVs impacting a newer passenger car. The proposed methodology can be a viable tool for estimatingthe DFR for newer road vehicles and to improve its crash compatibility with collision partners.

Predictors of erectile dysfunction after transperineal template prostate biopsy

Jo-Lynn Tan,Nathan Papa,Uri Hanegbi,Ross Snow,Jeremy Grummet,Sarah Mann,Adam Cuthbertson,Mark Frydenberg,Daniel Moon 대한비뇨의학회 2021 Investigative and Clinical Urology Vol.62 No.2

Purpose: To investigate the incidence and possible contributing factors of erectile dysfunction (ED) after transperineal template prostate biopsy (TTPB). Materials and Methods: Males undergoing TTPB were prospectively administered a Sexual Health Inventory for Men (SHIM) questionnaire before biopsy and one month after. SHIM questionnaires were repeated at 3- and 9-months for males not receiving interventional treatment. Sexually inactive males were excluded. Interval change in SHIM categories based upon baseline characteristics were evaluated. Multivariable logistic regression models were used to evaluate predictors of change in SHIM score category. Results: A total of 576 males were included in our sample. Of these, 450 (78%) males underwent their first biopsy. A decline in SHIM category within the immediate 4-weeks post-biopsy was reported by 167 males (31% of total eligible sample). Age was the strongest predictor of decline in SHIM category, the predicted probability of a decline in SHIM at age 50 was 10% (95% confidence interval [CI], 1%–19%), 32% at age 60 (95% CI, 25%–40%) and 36% at age 70 (95% CI, 29%–44%). For new onset ED, the predicted probability of ED within 4-weeks post-TTPB were 6.7% at age 50 (95% CI, 0%–15%), 26% at age 60 (95% CI, 17%–34%) and 31% at age 70 (95% CI, 21%–40%). Conclusions: Older age at biopsy is an independent predictor of immediate ED after TTPB in sexually active males. This association was observed in the subgroup with no pre-existing ED. These findings provide useful information when counselling males undergoing TTPB.

Vancomycin resistant enterococci in urine cultures: Antibiotic susceptibility trends over a decade at a tertiary hospital in the United Kingdom

Liam Toner,Nathan Papa,Sani H. Aliyu,Harveer Dev,Nathan Lawrentschuk,Samih Al-Hayek 대한비뇨의학회 2016 Investigative and Clinical Urology Vol.57 No.2

Purpose: Enterococci are a common cause of urinary tract infection and vancomycin-resistant strains are more difficult to treat. The purpose of this surveillance program was to assess the prevalence of and determine the risk factors for vancomycin resistance in adults among urinary isolates of Enterococcus sp. and to detail the antibiotic susceptibility profile, which can be used to guide empirical treatment. Materials and Methods: From 2005 to 2014 we retrospectively reviewed 5,528 positive Enterococcus sp. urine cultures recorded in a computerized laboratory results database at a tertiary teaching hospital in Cambridge, United Kingdom. Results: Of these cultures, 542 (9.8%) were vancomycin resistant. No longitudinal trend was observed in the proportion of vancomycin-resistant strains over the course of the study. We observed emerging resistance to nitrofurantoin with rates climbing from near zero to 40%. Ampicillin resistance fluctuated between 50% and 90%. Low resistance was observed for linezolid and quinupristin/dalfopristin. Female sex and inpatient status were identified as risk factors for vancomycin resistance. Conclusions: The incidence of vancomycin resistance among urinary isolates was stable over the last decade. Although resistance to nitrofurantoin has increased, it still serves as an appropriate first choice in uncomplicated urinary tract infection caused by vancomycin-resistant Enterococcus sp.

Lymph node yield in node-negative patients predicts cancer specific survival following radical cystectomy for transitional cell carcinoma

Jack Crozier,Nathan Papa,Marlon Perera,Michael Stewart,Jeremy Goad,Shomik Sengupta,Damien Bolton,Nathan Lawrentschuk 대한비뇨의학회 2017 Investigative and Clinical Urology Vol.58 No.6

Purpose: To determine the oncological implications of increased nodal dissection in node-negative bladder cancer during radical cystectomy in a contemporary Australian series. Materials and Methods: We performed a multicenter retrospective study, including more than 40 surgeons across 5 sites over a 10-year period. We identified 353 patients with primary bladder cancer undergoing radical cystectomy. Extent of lymphadenectomy was defined as follows; limited pelvic lymph node dissection (PLND) (perivesical, pelvic, and obturator), standard PLND (internal and external iliac) and extended PLND (common iliac). Multivariable cox proportional hazards and logistic regression models were used to determine LNY effect on cancer-specific survival. Results: Over the study period, the extent of dissection and lymph node yield increased considerably. In node-negative patients, lymph node yield (LNY) conferred a significantly improved cancer-specific survival. Compared to cases where LNY of 1 to 5 nodes were taken, the hazard ratio (HR) for 6 to 15 nodes harvested was 0.78 (95% confidence interval [CI], 0.43–1.39) and for greater than 15 nodes the HR was 0.31 (95% CI, 0.17–0.57), adjusted for age, sex, T stage, margin status, and year of surgery. The predicted probability of cancer-specific death within 2 years of cystectomy was 16% (95% CI, 13%–19%) with 10 nodes harvested, falling to 5.5% (95% CI, 0%–12%) with 30 nodes taken. Increasing harvest in all PLND templates conferred a survival benefit. Conclusions: The findings of the current study highlight the improved oncological outcomes with increased LNY, irrespective of the dissection template. Further prospective research is needed to aid LND data interpretation.

Dynamic Optimization of Switching States of an Hybrid Power Network

Aristide Tolok Nelem,Pierre Ele,Papa Alioune Ndiaye,Salomé Ndjakomo Essiane,Mathieu Jean Pierre Pesdjock 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.7

This paper presents the quality improvement of electric power and the optimization of the switching transient states. We have used a hybrid power generating network by combining the AHP (Hierarchical Process Analysis) and SASV (Automated Variable Structured Automation Systems) methods. This combination revisits the interest of the use of decision support methods in the management of the problem of source switching instants in a hybrid network. The results ensure not only optimal control, supervision, but also a considerable reduction in the repetitive switching that exists in such network and which is detrimental to sensitive loads; because it is perceived as power micro-interruptions. All data collected from different sources (photovoltaic field, battery, generator set and public electricity network), the models of this network and interconexion of different buses are presented.