Exploring the use of HPFRC and GFRP grids for the production of manhole covers

Corrosion of the steel reinforced concrete elements is one of the common pathologies that limits the long-term performance of urban infrastructures. This problem causes the loss of structural serviceability by decreasing the concrete-steel bond strength and reducing the cross section of the reinforcements. The present study introduces a new system for developing free-corrosion resistance prefabricated manhole covers for applications in the aggressive environments, i.e. wastewater collector systems, sewer systems, stormwater systems, etc. Fibre reinforced cement composites were applied in this system in order to suppress the corrodible steel mesh and maintain the structural ductility as well. Application of fibre reinforced polymer (FRP) system is adopted as the additional solution for increasing the load carrying capacity of these elements without concerns about corrosion. The effectiveness of the applied strategy in developing the manhole covers in terms of load carrying capacity and failure mode is evaluated in this research. Furthermore, this paper discusses a FEM-based simulation, aiming to address the possibility of calibrating the constitutive model parameters related to fracture modes I and II.

A FEM-based model to study the behaviour of corroded RC beams shear repaired by NSM CFRP rods technique

This paper presents the main features of finite element FE numerical model developed using the computer code FEMIX to predict the near-surface mounted NSM carbon-fiber-reinforced polymer CFRP rods shear repair contribution to corroded reinforced concrete RC beams. In the RC beams shear repaired with NSM technique, the Carbon Fibre Reinforced Polymer (CFRP) rods are placed inside pre-cut grooves onto the concrete cover of the RC beam’s lateral faces and are bonded to the concrete with high epoxy adhesive. Experimental and 3D numerical modelling results are presented in this paper in terms of load-deflection curves, failure modes and slip information of the tensile steel bars for 4 short corroded beams: two corroded beams (A1CL3-B and A1CL3-SB) and two control beams (A1T-B and A1T-SB), the beams noted with B were let repaired in bending only with NSM CFRP rods while the ones noted with SB were repaired in both bending and shear with NSM technique. The corrosion of the tensile steel bars and its effect on the shear capacity of the RC beams was discussed. Results showed that the FE model was able to capture the main aspects of the experimental load-deflection curves of the RC beams, moreover it has presented the experimental failure modes and FE numerical modelling crack patterns and both gave similar results for non-shear repaired beams which failed in diagonal tension mode of failure and for shear-repaired beams which failed due to large flexural crack at the middle of the beams along with the concrete crushing, three dimensional crack patterns were produced for shear-repaired beams in order to investigate the splitting cracks occurred at the middle of the beams and near the support.

Fault-tolerant radio coverage and connectivity in wireless mesh networks

Magdeburg, Univ., Fak. für Informatik, Diss., 2011

A Wireless Mesh Network NS-3 Simulation Model: Implementation and Performance Comparison With a Real Test-Bed

Wireless mesh networks present an attractive communication solution for various research and industrial projects. However, in many cases, the appropriate preliminary calculations which allow predicting the network behavior have to be made before the actual deployment. For such purposes, network simulation environments emulating the real network operation are often used. Within this paper, a behavior comparison of real wireless mesh network (based on 802.11s amendment) and the simulated one has been performed. The main objective of this work is to measure performance parameters of a real 802.11s wireless mesh network (average UDP throughput and average one-way delay) and compare the derived results with characteristics of a simulated wireless mesh network created with the NS-3 network simulation tool. Then, the results from both networks are compared and the corresponding conclusion is made. The corresponding results were derived from simulation model and real-worldtest-bed, showing that the behavior of both networks is similar. It confirms that the NS-3 simulation model is accurate and can be used in further research studies.

Arquitectura wormhole per a una NoC 2D-Mesh

Aquest projecte presenta la implementació d'un disseny, i la seva posterior síntesi en una FPGA, d'una arquitectura de tipus wormhole packet switching per a una infraestructura de NetWork-On-Chip amb una topologia 2D-Mesh. Agafant un router circuit switching com a punt de partida, s'han especificat els mòduls en Verilog per tal d'obtenir l'arquitectura wormhole desitjada. Dissenyar la màquina de control per governar els flits que conformen els paquets dins la NoC,i afegir les cues a la sortida del router (outuput queuing) són els punts principals d'aquest treball. A més, com a punt final s'han comparat ambdues arquitectures de router en termes de costos en àrea i en memòria i se n’han obtingut diverses conclusions i resultats experimentals.

Avaluació dels algorismes d'encaminament per a una NoC amb topologia Mesh 2D

Aquest projecte presenta una avaluació de les diferents alternatives d'encaminament per a una NoC amb una topologia mesh 2D. Per tal d'exposar aquestes alternatives s'ha estudiat la composició d'un router implementat amb l'algorisme determinista XY i s'ha adaptat per tal que aquest suportés els algorismes parcialment adaptatius West First, North Last i Negative First. Un cop tenim els routers implementats es disposa un estudi dels diferents algorismes i com cadascun d'aquests actuen en front uns mateixos estímuls per tal de crear una comparativa entre ells que ens faciliti una elecció a priori.

Albuterol delivery in an in vitro pediatric ventilator lung model: comparison of jet, ultrasonic, and mesh nebulizers.

OBJECTIVE: : To determine the influence of nebulizer types and nebulization modes on bronchodilator delivery in a mechanically ventilated pediatric lung model. DESIGN: : In vitro, laboratory study. SETTING: : Research laboratory of a university hospital. INTERVENTIONS: : Using albuterol as a marker, three nebulizer types (jet nebulizer, ultrasonic nebulizer, and vibrating-mesh nebulizer) were tested in three nebulization modes in a nonhumidified bench model mimicking the ventilatory pattern of a 10-kg infant. The amounts of albuterol deposited on the inspiratory filters (inhaled drug) at the end of the endotracheal tube, on the expiratory filters, and remaining in the nebulizers or in the ventilator circuit were determined. Particle size distribution of the nebulizers was also measured. MEASUREMENTS AND MAIN RESULTS: : The inhaled drug was 2.8% ± 0.5% for the jet nebulizer, 10.5% ± 2.3% for the ultrasonic nebulizer, and 5.4% ± 2.7% for the vibrating-mesh nebulizer in intermittent nebulization during the inspiratory phase (p < 0.01). The most efficient nebulizer was the vibrating-mesh nebulizer in continuous nebulization (13.3% ± 4.6%, p < 0.01). Depending on the nebulizers, a variable but important part of albuterol was observed as remaining in the nebulizers (jet and ultrasonic nebulizers), or being expired or lost in the ventilator circuit (all nebulizers). Only small particles (range 2.39-2.70 µm) reached the end of the endotracheal tube. CONCLUSIONS: : Important differences between nebulizer types and nebulization modes were seen for albuterol deposition at the end of the endotracheal tube in an in vitro pediatric ventilator-lung model. New aerosol devices, such as ultrasonic and vibrating-mesh nebulizers, were more efficient than the jet nebulizer.

Fibrin sealant for mesh fixation in endoscopic inguinal hernia repair: is there enough evidence for its routine use?

Fibrin sealing has recently evolved as a new technique for mesh fixation in endoscopic inguinal hernia repair. A comprehensive Medline search was carried out evaluating fibrin sealant for mesh fixation, and finally 12 studies were included (3 randomized trials, 3 nonrandomized trials, and 6 case series). The trials were assessed for operative time, seroma formation, recovery time, recurrence rate, and acute and chronic pain.There was a trend toward decreased operative times for fibrin sealing compared with mechanical stapling; however, the results for seroma formation remained contradictory. The most important finding was the reduced postoperative pain. Recovery times were lower after fibrin sealing and the recurrence rates showed no differences.Fibrin sealing for mesh fixation in the endoscopic inguinal hernia surgery is a promising alternative to mechanical stapling, which can be safely applied. As the overall quality of published data remains poor, further well-designed studies are needed until fibrin sealing can replace mechanical stapling as a new standard for mesh fixation.

Physically based walking simulation

Hem realitzat l’estudi de moviments humans i hem buscat la forma de poder crear aquests moviments en temps real sobre entorns digitals de forma que la feina que han de dur a terme els artistes i animadors sigui reduïda. Hem fet un estudi de les diferents tècniques d’animació de personatges que podem trobar actualment en l’industria de l’entreteniment així com les principals línies de recerca, estudiant detingudament la tècnica més utilitzada, la captura de moviments. La captura de moviments permet enregistrar els moviments d’una persona mitjançant sensors òptics, sensors magnètics i vídeo càmeres. Aquesta informació és emmagatzemada en arxius que després podran ser reproduïts per un personatge en temps real en una aplicació digital. Tot moviment enregistrat ha d’estar associat a un personatge, aquest és el procés de rigging, un dels punts que hem treballat ha estat la creació d’un sistema d’associació de l’esquelet amb la malla del personatge de forma semi-automàtica, reduint la feina de l’animador per a realitzar aquest procés. En les aplicacions en temps real com la realitat virtual, cada cop més s’està simulant l’entorn en el que viuen els personatges mitjançant les lleis de Newton, de forma que tot canvi en el moviment d’un cos ve donat per l’aplicació d’una força sobre aquest. La captura de moviments no escala bé amb aquests entorns degut a que no és capaç de crear noves animacions realistes a partir de l’enregistrada que depenguin de l’interacció amb l’entorn. L’objectiu final del nostre treball ha estat realitzar la creació d’animacions a partir de forces tal i com ho fem en la realitat en temps real. Per a això hem introduït un model muscular i un sistema de balanç sobre el personatge de forma que aquest pugui respondre a les interaccions amb l’entorn simulat mitjançant les lleis de Newton de manera realista.

Protocolos de encaminamiento en redes inalámbricas mesh: un estudio teórico y experimental

Una red inalámbrica mesh o en malla es un subtipo de red ad-hoc en la que los nodos que la forman pueden actuar además como puntos de acceso para otros dispositivos o como pasarelas a otras redes. Para ello se hacen necesarios protocolos que permitan a cada nodo saber cómo enviar datos a cualquier otro nodo de la red, así como informar de nodos nuevos o enlaces rotos. En este trabajo hacemos un repaso del estado del arte en cuanto a dichos protocolos de encaminamiento mesh, describiendo los más relevantes y que poseen implementaciones libres. Además se proporciona un estudio comparativo experimental del rendimiento ofrecido por cuatro de estas implementaciones: Open80211s, B.A.T.M.A.N., Babel y Meshias.

Surgery for incarcerated hernia: short-term outcome with or without mesh.

BACKGROUND: Incarcerated hernias represent about 5-15 % of all operated hernias. Tension-free mesh is the preferred technique for elective surgery due to low recurrence rates. There is however currently no consensus on the use of mesh for the treatment of incarcerated hernias, especially in case of bowel resection. AIM: The aims of this study were (i) to report our current practice for the treatment of incarcerated hernias, (ii) to identify risk factors for postoperative complications, and (iii) to assess the safety of mesh placement in potentially infected surgical fields. METHODS: This retrospective study included 166 consecutive patients who underwent emergency surgery for incarcerated hernia between January 2007 and January 2012 in two university hospitals. Demographics, surgical details, and short-term outcome were collected. Univariate analysis was employed to identify risk factors for overall, infectious, and major complications. RESULTS: Eighty-four patients (50.6 %) presented inguinal hernias, 43 femoral (25.9 %), 37 umbilical hernias (22.3 %), and 2 mixed hernias (1.2 %), respectively. Mesh was placed in 64 patients (38.5 %), including 5 patients with concomitant bowel resection. Overall morbidity occurred in 56 patients (32.7 %), and 8 patients (4.8 %) developed surgical site infections (SSI). Univariate risk factors for overall complications were ASA grade 3/4 (P = 0.03), diabetes (P = 0.05), cardiopathy (P = 0.001), aspirin use (P = 0.023), and bowel resection (P = 0.001) which was also the only identified risk factor for SSI (P = 0.03). In multivariate analysis, only bowel incarceration was associated with a higher rate of major morbidity (OR = 14.04; P = 0.01). CONCLUSION: Morbidity after surgery for incarcerated hernia remains high and depends on comorbidities and surgical presentation. The use of mesh could become current practice even in case of bowel resection.

Adverse effects of intraperitoneal onlay mesh used for incisional hernia repair

Context: In the past 50 years, the use of prosthetic mesh in surgery has dramatically¦changed the management of primary, as well as incisional hernias. Currently, there¦are a large number of different mesh brands and no consensus on the best material,¦nor the best mesh implantation technique to use. The purpose of this study is to¦illustrate the adverse effects of intraperitoneal onlay mesh used for incisional¦hernia repair encountered in patients treated at CHUV for complications after¦incisional hernia repair.¦Materials & Methods: This work is an observational retrospective study. A PubMed¦search and a systematic review of literature were performed. Thereafter, the medical¦records of 22 patients who presented with pain, abdominal discomfort, ileus, fistula,¦abscess, seroma, mesh infection or recurrent incisional hernia after a laparoscopic or¦open repair with intra-abdominal mesh were reviewed.¦Results: Twenty-two persons were reoperated for complications after incisional¦hernia repair with a prosthetic mesh. Ten were male and twelve female, with a¦median age of 58,6 years (range 24-82). Mesh placement was performed by a¦laparoscopic approach in nine patients and by open approach in thirteen others.¦Eight different mesh brands were found (Ultrapro®, Mersilene®, Parietex Composite®,¦Proceed®, DynaMesh®, Gore® DualMesh®, Permacol®, Titanium Metals UK Ltd®).¦Mean time from implantation and reoperation for complication was 34.2 months¦(range 1-147). In our sample of 22 patients, 21 (96%) presented mesh adhesion and¦15 (68%) presented hernia recurrence. Others complications like mesh shrinkage,¦mesh migration, nerve entrapment, seroma, fistula and abscess were also evaluated.¦Conclusion: The majority of articles deal with complications induced by¦intraperitoneal prosthetic mesh, but the effectiveness of mesh has been studied¦mostly on experimental models. Actually and as shown in the present study,¦intraperitoneal mesh placement was associated with severe complications witch may¦potentially be life threatening. In our opinion, intraperitoneal mesh placement should¦only be reserved in exceptional situations, when the modified Rives-Stoppa could not¦be achieved and when tissues covering the mesh are insufficient.

Laparoscopic inguinal hernia repair with extraperitoneal double-mesh technique.

Totally extraperitoneal laparoscopic hernia repair is an efficient but technically demanding procedure. As mechanisms of hernia recurrence may be related to these technical difficulties, we have modified a previously described double-mesh technique in an effort to simplify the procedure. Extraperitoneal laparoscopic hernia repairs were performed in 82 male and 17 female patients having inguinal, femoral, and recurrent bilateral hernias. A standard propylene mesh measuring 15 x 15 cm was cut into two pieces of 4 x 15 cm and 11 x 15 cm. The smaller mesh was placed over both inguinal rings without splitting. The larger mesh was then inserted over the first mesh and stapled to low-risk zones, reinforcing the large-vessel area and the nerve transition zone. The mean procedure duration was 60 minutes for unilateral and 100 minutes for bilateral hernia repair. Patients were discharged from the hospital within 48 hours. The mean postoperative follow-up was 22 months, with no recurrences, neuralgia, or bleeding complications. Over a 2-year period, this technique was found to be satisfactory without recurrences or significant complications. In our hands, this technique was easier to perform: it allows for a less than perfect positioning of the meshes and avoids most of the stapling to crucial zones.

Posterior vaginal wall repair with synthetic absorbable mesh: A new technique for and old procedure

The objective of this study was to assess the applicability of posterior wall repair with a synthetic absorbable mesh. Between January and September 1996, five posterior repairs using absorbable synthetic meshes were performed. Five posterior wall repairs in patients matched for age, parity, and rectocele degree were performed according to usual procedures during the same period, and were used as controls. No febrile morbidity, cuff or posterior vaginal wall infections, thrombophlebitis, rectal injury, or hemorrhagic complications were observed in the 10 women who entered the study. In summary, posterior wall repair can be easily performed with an absorbable soft tissue patch, theoretically preserving sexual activity, and probably offers better functional results with longer experience, thus providing a safe and useful procedure in sexually active women.