Use of carbon fibbers for strengthening of the reinforced concrete structures

The need for structural rehabilitation of concrete structures all over the world is a wellknown problem and a great amount of research is going on in this field. There can be manyreasons for strengthening such as increased loads, design and construction faults, change ofstructural system, and so on. Economic comparison between the cost of a full or partialreplacing to a building and the intervention of a localized reinforcening makes us give thepriority to the second solution, for reasons like the urban connections, the architecturaleffects, the natural landscapes etc. All these reasons, have pushed the world of technologicalresearch to establish new technics for reinforcening the structures with new compositematerials, mainly reinforced with fibers of different nature.Composite materials heard otherwise with the abbreviation FRP consist in continuedfibers enclosed in a matrix (adhesive substances) of polymers origin. Carbon fibers representa resistant element toward external loads and actions, while the polymer composition has themission to transfer constraints in fibers and between fibers and also protects them from thesurrounding environment. The use of CFRP is a competitive method both regarding structuralperformance and economical aspects which refers to the bonding of a thin carbon fiberlaminate or sheet to the surface of the structure in order to act as an outer reinforcement layer.Mechanical properties of composites depend on several different factors like themechanical properties of the carbon fibers themselves, their nature and the technic used tomanufacture them.Composite materials provide high resistance to traction, excellent resistance tocorrosion and a low specific weight so for they are widely used in the construction field, onreinforced concrete elements, masonry, wood, steel.In this study article will be also shown a numerical implementation of designing a beamin flexing, reinforced with carbon fibers

The Analysis and the Design of the Reinforced Concrete Elements and the Algorithm in the Calculation of these Elements under the Shear Forces

During the process of the design for the reinforced concrete elements besides the calculation of the bending moment, another important calculation is the one made for these elements when they are under the shear forces. This calculation is made in the ultimate limit state, SLU. This paper will present all theoretical bases and algorithm calculations of reinforced concrete elements under the shear forces, based on the European rules (Eurocodes) and mainly EC2 and EC8. The study of reinforced concrete elements under the shear forces is complex process. It cannot be sufficient the analysis of one section in the study of reinforced concrete elements, in the contrary of what happens usually. The analysis of the reinforced concrete structures under the shear forces should be made by analyzing all its elements entirely. The behaviour of the reinforced concrete elements in its plastic phase is complicated and it directly affects in the size of the bearing capacity of element in the shear forces. In the size of the bearing capacity of element in the shear forces also the quantity of the longitudinal reinforcement, the quantity of transversal reinforcement, the type and the position of forces, the form of the transversal section, etc. The effect of the transversal (shear) forces is important in studying the behaviour of the element. The analysis is made by approximating the element with a truss, where the tension elements of this truss are represented by the reinforcement and the pressed elements are represented by the press concrete. The factors that mostly affect the capacity of the reinforced concrete element shear process are the longitudinal quantity of reinforcement, the size of gravel and the transversal size of the element. In this paper will be presented several numerical examples and the algorithm for calculating the concrete elements from shear forces

IN VIVO EVALUATION OF MISOPROSTOL FLOATING MICROSPHERES

Prostaglandin (PG) has been reported to be an important protective and acid suppressive factor in the gastric mucosa. The objective of the study was to develop and evaluate a stomach specific drug delivery system for controlled release of Misoprostal a PE analogue for gastric ulcer induced NSAIDs. Floating microspheres were prepared by emulsification-solvent evaporation method using ethyl cellulose as a polymer, carbo pol as mucoadhesive polymer. Ulcers were induced by the oral administration of absolute ethanol (5 mL/kg) to 24 h fasted Wistar male rats (n=8), weighing 200 g. Sodium bicarbonate solution, misoprostal solution and drug loaded microspheres were tested. Formulations were administered orally 1h before the administration of ethanol. Prior to the oral administration, rats were anesthetized with ethylic ether. After 2 h of ethanol administration, animals were sacrificedthe stomachs were removed, opened along .he greater curvature and examined for lesion measurements. Ulcer indexes (UI) were calculated. The in vivo evaluation showed that ulcer index values were 0.61 ± 0.14 for the sodium bicarbonate solution, 0.58 ±O.18 for the misoprostal and 0.11 :i: 0.06 for the misoprostal-Ioaded microspheres. The Kruskal- Wallis test detected statistical differences (p =0.002) between the ulcer indexes. The multiple analyses (Student-Newman-Keuls) showed that the misoprostal loaded microspheres presented a gastric ulcer index statistically lower than that of the sodium bicarbonate solution (p = 0.001) and the misoprostal solution (p = 0.021). The percentages of ulceration inhibition were 31\u27 and 75% after the administration of misoprostal solution and microspheres, respectively. In conclusion, the in vivo evaluation showed that the microspheres presented ulcer index lower than the solutions, showing that misoprostal-loaded microspheres were efficient in protecting the stomach against ulcer formation

The Calculation of a Concrete Reinforcement Under the Action of Torsion Moment, According to Eurocode and Albanian Technical Rules

The objective of this research is to introduce the reader to the calculation of a concrete reinforced element under the action of the torsion moment by comparing the two methods, Eurocode and Albanian Technical Rules. Particularly we will present the factors that affect the calculation and the final result. During a long period of time the action of torsion on a concrete reinforced element is not considered to be very important. The traditional calculating methods led to designing with reserves. As a result the longitudinal and transversal reinforcement due to bending, shear, compression or tension was enough even for torsion. With the progress of the calculating methods are designs concrete reinforced elements that have smaller dimensions and a reduced reinforcement. Consequently it is important to calculate correctly even the effect of torsion. Usually torsion is combined with bending and shear. In some cases it is combined with compression or tension. When torsion is combined with bending, shear, compression or tension, the concrete reinforced element must be controlled carefully in order to consider all these effects. In fact, torsion is noticed very often in the performance of a concrete reinforced element. Usually the vertical loads don’t pass through the center of gravity of the sect ion. Almost every time they are deflected, causing torsion moments besides bending moments and shear forces. But this kind of torsion is not considered. Here we come to a question, when should torsion be considered and when not? This question and many other ones will be answered in this article. The similarities, differences and the factors that affect on both chosen methods will also be part of the article, especially the effect of section dimensions

Industrial Pavements Design

The objective of this research is to describe a set of specific techniques and procedures for the proper construction of concrete pavements for industrial use, usually referred to as industrial pavements.In particular, we will define the mechanical and rheological properties of concrete, necessary for the pavements to maintain the functionality for the entire life of the project. These properties are established taking into account the needs during the execution of the project, static and dynamic loads, and the possible conditions of aggression prompted by the environment in which the floor is located. The specifications about the materials for the construction of any surface layer resistant to abrasions must be determined. The materials used in the execution of the contraction joints, insulation joints and construction joints should also be determined.The reinforcement, in concrete pavements, is generally present in the form of welded mesh, without structural functions. It must absorb the forces generated by movements of thermohygrometric nature. Besides welded mesh, may also be used metallic fibers. Adding fibers to concrete, creates a material with high ductility, capable to endure special stresses (such as accidental stresses caused by falling of metal objects, the strong braking of cars, by the forces of friction in the wheels of the vehicles along the curves, dragging heavy objects etc..) Establishing sufficiently metal fibers allows to increases the flexural strength of the slab. Fibers in the right form, section, length, amount may be added during the mixing of the concrete or they may be added directly to the object. Besides metal fibers, synthetic fibers with different characteristics and compositions can also be used. They have the same function as metal fibers

IN VIVO EVALUATION OF MISOPROSTOL FLOATING MICROSPHERES

Prostaglandin  (PG)  has  been  reported  to  be  an  important protective  and  acid  suppressive  factor  in  the  gastric  mucosa.  The objective  of  the  study  was  to  develop  and  evaluate  a  stomach specific  drug  delivery  system  for  controlled  release  of  Misoprostal  a PE analogue for gastric ulcer induced NSAIDs. Floating microspheres were  prepared  by  emulsification-solvent  evaporation  method  using ethyl  cellulose  as  a  polymer,  carbopol  as  mucoadhesive  polymer. Ulcers were induced by the oral administration of absolute ethanol (5 mL/kg)  to  24  h  fasted  Wistar  male  rats  (n=8),  weighing  200  g. Sodium  bicarbonate  solution,  misoprostal  solution  and  drug  loaded microspheres were tested. Formulations were administered orally 1h before the administration of ethanol. Prior to the oral administration, rats  were  anesthetized  with  ethylic  ether.  After  2  h  of  ethanol administration,  animals  were  sacrificed;  the  stomachs  were removed,  opened  along  he  greater  curvature  and  examined  for lesion measurements. Ulcer indexes (UI) were calculated. The in vivo evaluation showed that ulcer  index values were 0.61 ± 0.14 for the sodium  bicarbonate  solution,  0.58  ±0.18  for  the  misoprostal  and 0.11  ±  0.06  for  the  misoprostal-loaded  microspheres.  The  KruskalWallis  test  detected  statistical  differences  (p  =0.002)  between  the ulcer  indexes.  The  multiple  analyses  (Student-Newman-Keuls) showed  that  the  misoprostal  loaded  microspheres  presented  a gastric  ulcer  index  statistically  lower  than  that  of  the  sodium bicarbonate  solution  (p  =  0.001)  and  the  misoprostal  solution  (p  = 0.021).  The  percentages  of  ulceration  inhibition  were  31  and  75% after  the  administration  of  misoprostal  solution  and  microspheres, respectively.  In  conclusion,  the  in  vivo  evaluation  showed  that  the microspheres  presented  ulcer  index  lower  than  the  solutions, showing  that  misoprostal-loaded  microspheres  were  efficient  in protecting the stomach against ulcer formation.Key words: Misoprostal, microspheres, ulcer index,

Floating tablets of hydralazine hydrochloride: optimization and evaluation

Hydralazine hydrochloride has a half-life of 2 to 4 hours with an oral bioavailability of 26-50%. Since hydralazine has a demethylating effect on various suppressor genes, it can be used in various types of cancer to support chemotherapy. The purpose of this study was to optimize and evaluate floating tablets of hydralazine hydrochloride designed to prolong the gastric residence time and to provide controlled release of the drug for 14 h. The floating tablets of hydralazine hydrochloride were prepared by the wet granulation method. Semi-synthetic polymers of hydroxy propyl methyl cellulose (HPMC K100M) and ethyl cellulose were used as the release retarding agents. A 2² factorial design was applied to systematically optimize the drug release profile. The concentrations of HPMC K100M and ethyl cellulose were optimized to provide controlled release of hydralazine for 14h. Non-Fickian diffusion release transport was confirmed as the release mechanism for the optimized formulation and the predicted values agreed well with the experimental values. Drug excipient compatibility studies were investigated by FTIR, DSC and XRD. These data indicate that there were no chemical interactions between the drug and the polymer. In vivo X-ray imaging showed floating tablet performance in rabbits.O cloridrato de hidralazina apresenta meia-vida de 2 a 4 horas, com biodisponibilidade oral de 26-50%. Uma vez que a hidralazina possui efeito desmetilante em vários genes supressores, ela pode ser utilizada para diversos tipos de câncer, em apoio à quimioterapia. O objetivo deste estudo foi o de avaliar e otimizar comprimidos flutuantes de cloridrato de hidralazina, planejados para prolongar o tempo de residência gástrica e proporcionar liberação controlada do fármaco por 14 h. Os comprimidos flutuantes de cloridrato de hidralazina foram preparados pelo método de granulação úmida. Polímeros semi-sintéticos de hidroxipropiletil celulose (HPMCK100M) e acetato de celulose foram utilizados como agente de retardamento de liberação. Aplicou-se planejamento fatorial 2² para otimizar sistematicamente o perfil de liberação do fármaco. As concentrações de HPMCK100M e de etilcelulose foram otimizadas para se obter liberação controlada de hidralazina durante 14 h. O transporte de liberação de difusão não-Fickiana foi confirmado como o mecanismo de liberação para a formulação otimizada e os valores previstos estiveram de acordo com os valores experimentais. Estudos de compatibilidade entre fármaco e excipiente foram realizados por FTIR, DSC e DRX. Estes dados indicaram que não havia interação química entre o fármaco e o polímero. Imagens de raios-X in vivo mostraram o desempenho dos comprimidos flutuantes em coelhos

Application of data mining techniques using SAS software

Data mining has captured the hearts and minds of business analysts seeking a solution forexploring and modeling vastly larger, more complex and less well-behaved datasets. Exploratorydata analysis, typically consisting of activities like statistical visualization, hypothesis generation,and introductory model fitting is a vital first step in any successful data mining venture.Exploratory data analysis produces direct benefits for data miners in enhanced understanding ofdata, improved clarity and confidence of the modeling results, and avoidance of pitfalls early inthe process. By using data mining techniques to analyze the data that is accumulating and fillingvast data warehouses, organizations can harness more insight from their large data stores to driveproactive decision making. SAS data mining software can surface patterns and trends in yourdata that you may never have thought to look for. This paper will review the usefulness of SAS Tsoftware for exploratory data analysis, interactive regression modeling, and advancedmultidimensional data visualizatio