12 research outputs found

    Reinforcement of concrete using Glass Fiber Reinforced Polymer

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    The use of composite materials such as fiber reinforced polymers in strengthening and repairing of structural elements, particularly those made of reinforced concrete, is widely spreading. Among the fiber reinforced polymers (FRP) used for concrete strengthening, GFRP because they are more ductile and cheaper than carbon fibers and can be considered as an alternative solution to repair and strengthen concrete elements. The GFRP enhance significantly the ductility and strength of concrete by forming perfect adhesive bond between the wrapping material and concrete. Present study mainly emphasizes on effectiveness of external GFRP strengthening for concrete beams and columns. Total five circular concrete columns of 320 mm in height and 160 mm in diameter, and 30 concrete rectangular beams with a section of 40 mmx40 mm and 160 mm in length. Two columns were control and the rest three columns were strengthened with three types of GFRP. For beams, fifteen of them was control and the others were strengthened by GFRP with U-shape. All the test specimens were loaded to fail in axial compression and strain for columns, and under three-point bending for beams. The test results clearly demonstrated that compared with the ordinary concrete, the axial load carrying capacity and flexural strength increase for the reinforced concrete no matter the kind of the GFRP used even if it was in different storage condition

    Reinforcement of concrete using Glass Fiber Reinforced Polymer

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    The use of composite materials such as fiber reinforced polymers in strengthening and repairing of structural elements, particularly those made of reinforced concrete, is widely spreading. Among the fiber reinforced polymers (FRP) used for concrete strengthening, GFRP because they are more ductile and cheaper than carbon fibers and can be considered as an alternative solution to repair and strengthen concrete elements. The GFRP enhance significantly the ductility and strength of concrete by forming perfect adhesive bond between the wrapping material and concrete. Present study mainly emphasizes on effectiveness of external GFRP strengthening for concrete beams and columns. Total five circular concrete columns of 320 mm in height and 160 mm in diameter, and 30 concrete rectangular beams with a section of 40 mmx40 mm and 160 mm in length. Two columns were control and the rest three columns were strengthened with three types of GFRP. For beams, fifteen of them was control and the others were strengthened by GFRP with U-shape. All the test specimens were loaded to fail in axial compression and strain for columns, and under three-point bending for beams. The test results clearly demonstrated that compared with the ordinary concrete, the axial load carrying capacity and flexural strength increase for the reinforced concrete no matter the kind of the GFRP used even if it was in different storage condition

    Influence of bonded length of the Carbon Fiber Reinforced Polymer Plates on the behavior of a concrete beam

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    Sometimes Aged or Damaged Structures need to be reinforced and retrofitted to enhance their performances and structural life, for this reason, the rehabilitation has been the subject of extensive research. The strengthening Reinforced Concrete structures is one of the most difficult and important tasks of civil engineering. Among the ways used to strength the concrete; the reinforcement using Carbon fiber reinforced polymer. This material has proved to be more efficient than other composites because of its high elastics modulus, its durability and this kind of materials are less affected by corrosive environmental conditions. The technique used in this study will be the external bonding of Carbon fiber reinforced polymer (CFRP) to a concrete beam. In this paper, the focus will be on the influence of bonded length of the CFRP Plates on the global behavior of the beam. The study is developed by the finite element program ABAQUS and will contain 11 specimens with a dimension of 100*200*1000mm and the length of the CFRP will be 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm, 800 mm, 900 mm, and a fully reinforced beam. Numerical results are presented and discussed herein

    Emergence of Klebsiella pneumoniae Carbapenemase (blaKPC-2) in members of the Enterobacteriaceae family in Palestine

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    Abstract Background: The global spread of carbapenem resistant Enterobacteriaceae (CRE) has limited the physicians’ antimicrobial treatment options of infected patients. CRE’s which carry the Klebsiella pneumonia Carbapenemase (blaKPC) resistance mechanism have been rapidly spreading in many parts of the world, and have been responsible for high patients’ morbidity and mortality. Methods: Two protocols recommended by the Center for Disease Control and Prevention (CDC) were followed to detect CRE’s in Palestine. In addition, the antimicrobial sensitivity patterns for several antibiotic classes were determined for the isolated CRE’s by the disc diffusion method according to the clinical and laboratory standard institute (CLSI) M100-S22 guidelines. The Minimal Inhibitory Concentrations (MICs) of the carbapenem, ertapenem, imipenem and meropenem were determined for all the CRE’s by E-test. The isolates β-lactam resistance mechanisms were further investigated by analyzing 31 different types of β–lactamase genes by polymerase chain reaction (PCR). Results: Four bacterial isolates, 3 Enterobacter cloacae and 1 Klebsiella pneumoniae, were determined to be non-susceptible to one or all of the carbapenems (ertapenem, imipenem and meropenem) tested. All isolates which carried the blaKPC-2 gene showed an extreme drug resistance profile. These isolates were resistant to all β-lactam antibiotics, co-trimoxazole and gentamicin, while susceptible to only amikacin and colistin sulfate. Different combination of plasmid encoded b–lactamase genes (blaTEM, blaSHV, blaOXA-1, blaMIR-1, blaGES-23 and blaKPC-2) were present in these isolates. Of interest, was the isolation of the first E. cloacae strains co-producing the blaKPC-2 and a novel blaGES-23 β-lactamase. Conclusions: The presence of all these plasmid encoded b-lactamase in Palestine is alarming and mandates actions to be taken to control antibiotics usage and the activation of hospital infection control programs in order to prevent the spread of these extremely drug resistant bacteria

    Acute ocular chemical injury: a descriptive assessment and management review at St. John Eye Hospital, Jerusalem, Palestine

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    Background: The purpose of the study was to assess caregivers’ compliance with the management protocol for chemical injury at St. John Eye Hospital, Jerusalem. Material and methods: Charts of all new chemical injury patients who presented to St. John Eye Hospital, Jerusalem, between January and December 2019 were retrospectively reviewed. Data categories collected included: presentation, age, sex, injury, irrigation, lids, visual acuity, slit-lamp examination (SLE), management plan, and medications given. Data were stored and analysed using Excel. Results: Patients’ presentation date and time, sex, and age were recorded in over 90% of cases. The mechanism of injury and type of offending chemical were recorded in 65% of cases. The irrigating solution was identified in 50% of cases. Corrected visual acuity was recorded in both eyes in almost 50% of cases. Limbal ischemia was documented in 45% of cases, and intraocular pressure (IOP) was recorded in 25%. The management plan and explanation of the condition to patients were documented in less than 50% of cases. Antibiotics and steroids (drops/ointment) were prescribed in 92.5% of cases. Conclusions: The results of this study reveal that our documentation needs improvement for several parameters. Several recommendations were formulated: Emphasize to caregivers that irrigation must be done first. Corrected visual acuity should be attempted for both eyes in all cases, and reasons for not recording it should be documented. It is important to document and record limbus details, iris details, and IOP in all cases.

    Seismic Retrofitting: Reinforced Concrete (RC) shear wall versus Reinforcement of RC element by Carbon Fiber Reinforced Polymer (CFRP) using PUSHOVER analysis

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    Seismic retrofitting of constructions vulnerable to earthquakes is a current problem of great political and social relevance. During the last sixty years, moderate to severe earthquakes have occurred in Morocco (specifically in Agadir 1960 and Hoceima 2004). Such events have clearly shown the vulnerability of the building stock in particular and of the built environment in general. Hence, it is very much essential to retrofit the vulnerable building to cope up for the next damaging earthquake. In this paper, the focus will be on a comparative study between two techniques of seismic retrofitting, the first one is a reinforcement using carbon fiber reinforced polymer (CFRP) applied to RC elements by bonding , and the second one is a reinforcement with a shear wall. For this study, we will use a non-linear static analysis -also known as Pushover analysis - on a reinforced concrete structure consisting of beams and columns, and composed from eight storey with a gross area of 240 m², designed conforming to the Moroccan Seismic code[1]

    Seismic Retrofitting: Reinforced Concrete (RC) shear wall versus Reinforcement of RC element by Carbon Fiber Reinforced Polymer (CFRP) using PUSHOVER analysis

    No full text
    Seismic retrofitting of constructions vulnerable to earthquakes is a current problem of great political and social relevance. During the last sixty years, moderate to severe earthquakes have occurred in Morocco (specifically in Agadir 1960 and Hoceima 2004). Such events have clearly shown the vulnerability of the building stock in particular and of the built environment in general. Hence, it is very much essential to retrofit the vulnerable building to cope up for the next damaging earthquake. In this paper, the focus will be on a comparative study between two techniques of seismic retrofitting, the first one is a reinforcement using carbon fiber reinforced polymer (CFRP) applied to RC elements by bonding , and the second one is a reinforcement with a shear wall. For this study, we will use a non-linear static analysis -also known as Pushover analysis - on a reinforced concrete structure consisting of beams and columns, and composed from eight storey with a gross area of 240 m², designed conforming to the Moroccan Seismic code[1]

    Phytochemistry, antioxidant, anticancer, and acute toxicity of traditional medicinal food Biarum bovei (Kardeh)

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    Abstract Background The Biarum species (Kardeh) has been consumed as a traditional functional food and medicine for decades. The current study investigates the phytochemistry, in-vitro and in-vivo bioactivities of methanol extracts of B. bovei. Methods The Gas-chromatography mass spectrophotometer (GS/GS-MS) was used to analyze the phytochemical profile of the methanol extracts of B. bovei leaves and corms. The B. bovei extracts (BBE) were also investigated for in-vitro antioxidant, anticancer, and in-vivo acute toxicity (2000 mg/kg) activities. Results The chemical profiling of BBE revealed mainly fatty acids, phytosterol, alcohols, and hydrocarbon compounds. Namely, Linoleic acid, eliadic acid, palmitic acid, 22,23-dihydro-stigmasterol, and campesterol. The antioxidant activity of BBE ranged between 0.24–3.85 μg TE/mL based on different assays. The extracts also exhibited significant anticancer activity against DU-145 (prostate cancer cells), MCF-7 (human breast adenocarcinoma), and HeLa (human cervical cancer) cell lines with IC50 values ranging between 22.73–44.24 μg/mL. Rats fed on 2000 mg/kg dosage of BBE showed absence of any toxicological sign or serum biochemical changes. Conclusion The detected phytochemicals and bioactivities of BBE scientifically backup the folkloric usage as an important source of nutraceuticals and alternative medicine for oxidative stress-related diseases and carcinogenesis inhibition

    Pinostrobin attenuates azoxymethane-induced colorectal cytotoxicity in rats through augmentation of apoptotic Bax/Bcl-2 proteins and antioxidants

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    Objectives: Pinostrobin (5-hydroxy-7-methoxyflavanone; PN) is a natural active ingredient with numerous biological activities extensively utilized in tumour chemotherapy. The present study investigates the chemo-preventive potentials of PN on azoxymethane-mediated colonic aberrant crypt foci in rats. Methods: Sprague Dawley rats clustered into five groups, normal control (A) and cancer controls were subcutaneously injected with normal saline and 15 mg/kg azoxymethane, respectively, and nourished on 10% tween 20 and fed on 10% tween 20; reference control (C), injected with 15 mg/kg azoxymethane and injected (intraperitoneal) with 35 mg/kg 5-fluorouracil (5-FU); D and E rat groups received a subcutaneous injection of 15 mg/kg azoxymethane and nourished on 30 and 60 mg/kg of PN, respectively. Results: The acute toxicity trial showed a lack of any abnormal signs or mortality in rats ingested with 250 and 500 mg/kg of PN. The gross morphology of colon tissues revealed significantly lower total colonic aberrant crypt foci incidence in PN-treated rats than that of cancer controls. Histological examination of colon tissues showed increased aberrant crypt foci availability with bizarrely elongated nuclei, stratified cells and higher depletion of the submucosal glands in cancer controls. PN treatment caused positive modulation of apoptotic (Bax and Bcl-2) proteins and inflammatory cytokines (TNF-α, IL-6 and IL-10). Moreover, rats fed on PN had significantly higher antioxidants (superoxide dismutase) and lower malondialdehyde concentrations in their colon tissue homogenates. Conclusion: The chemoprotective efficiency of PN against azoxymethane-induced aberrant crypt foci is shown by lower aberrant crypt foci values and higher aberrant crypt foci inhibition percentage, possibly through augmentation of genes responsible for apoptotic cascade and inflammations originating from azoxymethane oxidative stress insults
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