Shear capacity prediction for stirrup-corroded RC beams strengthened with FRP

Corrosion of steel reinforcement represents one of the main causes of deterioration and degradation of reinforced concrete (RC) structures. Shear reinforcements (stirrups) as an outer reinforcement in RC beams are more susceptible to corrosion problems and damage. This paper describes an analytical procedure for predicting the shear capacity of stirrup-corroded RC beams strengthened in shear using FRP laminates. The procedure shows how to incorporate the effects of the damages due to corrosion of stirrups into the design equations. An experimental investigation has been conducted to provide experimental data on the shear capacity of RC beams with corrosion-damaged stirrups strengthened using carbon fiber reinforced polymer (CFRP) sheets. The experimental study comprised three beams of 200 mm wide, 350 mm deep, and 2800 mm long. The steel stirrups in the beams were corroded using an accelerated corrosion technique. After CFRP strengthening, the beams were tested in four-point bending under a simply supported span of 2400 mm. The shear capacity of the strengthened beams was predicted using the proposed procedure and compared with the experimental ones. Good correlations were found between the predicted and experimental shear strength of the beams

Simulation: Early Detection of Brain Vessels Stroke by Applying Electromagnetic Waves Non-Invasively

Introduction: Early recognition of stroke with its two types Ischemic and Hemorrhagic, is one of the most crucial research points, commonly used methods are CT- (computerized tomography), and MRI- (Magnetic resonance imaging). These techniques cause a delay in the detection of the condition, which causes permanent disability. The main reason behind the fatal consequences of stroke is the delay of detection. Therefore, this research paper aims to early detection of the type of stroke without delay until the appropriate diagnosis of each type is made, and then the appropriate treatment without delay. Method: Using a non-invasive and fast technique to determine the stroke type by wave, we simulate and design a vessel containing a liquid as a laminar flow with the same density and velocity of blood, and it was surrounded by a Homogenized multi-turn coil consisting of (n) turns to represent the magnetic field, using specific frequency (HZ) with Electrical field in coil current (A) to see the changing in magnetic flux density (MFD), Depending on the changes in MFD, the flow of blood in laminar flow can be affected by clotting (Ischemic) or Hemorrhagic (cutting) in our vessel designed. We have built three different scenarios to apply the technique which are: First: Normal Scenario (where the blood in vessel has no problem), second: clotting (ischemic, where the vessel blocked in specific three position) and Third: Cutting (Hemorrhagic, where the vessel cut in certain nine positions). Results: This paper presents-through our own design-the studying of applying the electromagnetic waves on blood inside the vessel to detect the stroke type in our three scenarios (normal, ischemic three positions or hemorrhagic nine positions), Studying the magnetic field and laminar flow. This study covered in three areas. First: coil geometry analysis, Second: stationary, and Third: frequency domain. through the changes in Magnetic Flux Density -MFD- waves. The results were promising and distinct for distinguishing between the three scenarios which are normal, ischemic (3 positions) and hemorrhagic (9 positions) the results of MFD are: 0.09 to 3.3*10^-3, 0.08 to 3.15*10^-4, 0.15 to 6.2*10^-3 respectively

Induciranje pluripotentnih matičnih stanica upotrebom mRNA: učinak valproične kiseline, 5-azacitidina i askorbinske kiseline

In the bourgeoning fields of tissue engineering and regenerative medicine, induced pluripotent stem cells (iPSCs) technology with gene therapy are promising candidates for alternative stem cell source and cell transplantation. In this study, small molecules as anti-oxidant; ascorbic acid (ASA), histone deacetylase inhibitors (HDACi); Valproic acid (VPA), and DNA methyltransferase inhibitors (DNMTi); 5-Azacytidine (5-AzaC) were examined during the generation of murine iPSCs using mRNA of Yamanaka factors from mouse embryonic fibroblasts (MEFs). These modulators were selected based on their well-known effect on the epigenetic status and chromatin modification during early reprogramming. iPSC generation was performed by using synthesized mRNAs of Yamanaka factors Oct4, Sox2, c-Myc, and Klf4 (OSCK) as a standard reprogramming strategy. Both morphological changes and the expression level of the pluripotency markers were examined. 5-AzaC with 1 μM concentration has a slightly toxic effect on the cells, affecting its proliferation and growing efficiency. In contrast, the use of VPA or ASA led to a two-fold increase in the number of iPSC colonies. The iPSCs cultured with the addition of VPA or ASA showed a high expression of the tested pluripotency markers, with a significant increase, more than that of the cells cultured with the addition of 5-AzaC. These findings shed light on the role of ASA, VPA, and 5-AzaC during murine iPSCs generation using a mRNA reprogramming strategy.Ubrzani razvoj u područjima tkivnog inženjerstva i regenerativne medicine, potaknuo je tehnologiju pluripotentnih matičnih stanica (iPSCs) koja zajedno s genskom terapijom predstavlja obečavajući izvor matičnih odnosno transplantacijskih stanica. U ovom su radu, za vrijeme stvaranja mišjih iPSC-a upotrebom mRNA Yamanaka faktora od mišjih embrionalnih fibroblasta (MEF), istraženi učinci različitih modulatora: malih molekula kao antioksidansa, askorbinske kiseline (ASA), inhibitora histonske deacetilaze (HDACi), valproične kiseline (VPA), inhibitora DNA metiltransferaze (DNMTi) i 5-azacitidina (5-AzaC). Ovi su modulatori odabrani zbog njihova dobro poznatog učinka na epigenetski status i modifikaciju kromatina za vrijeme ranog reprogramiranja. Stvaranje iPSC-a postignuto je upotrebom sintetiziranih mRNA Yamanaka faktora Oct4, Sox2, c-Myc i Klf4 (OSCK). Istražene su i morfološke promjene i razina ekspresije markera pluripotencije. 5-AzaC s koncentracijom od 1 μM imao je mali toksičan učinak na stanice, utječući na proliferaciju i njihov rast. Nasuprot tome, upotreba VPA-a ili ASA-e dovela je do dvostrukog povećanja broja iPSC kolonija. iPSC kultura s dodatkom VPA-a ili ASA-e pokazala je visoku ekspresiju testiranih markera pluripotencije, sa znakovitim višom razinom u odnosu na stanice kojima je dodan 5-AzaC. Ovi rezultati rasvjetljuju ulogu ASA-e, VPA-a i 5-AzaC-a za vrijeme stvaranja mišjih iPSC-a primjenom strategije reprogramiranja mRNA

Influence of the analysis technique on estimating hepatic iron content using MRI

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134998/1/jmri25317.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134998/2/jmri25317_am.pd

Effect of stirrup corrosion on the shear strength of reinforced concrete short beams

The effect of stirrups damage due to corrosion on the shear strength and behaviour of reinforced concrete beams was experimentally investigated. A total of fourteen full-scale reinforced concrete beams were constructed and tested under four-point bending up to failure. The test beams were 200 mm wide, 350 mm deep, and 2800 mm long. The reinforcing stirrups of nine of the beams were subjected to accelerated corrosion prior to structural testing. The test variables were the corrosion damage level, spacing of stirrups, and shear span to depth ratio. The beams were tested under shear span to depth ratio of 2 or 1 representing short or deep members. The test results indicated that the corroded beams exhibited degradation in stiffness and shear strength in comparison to the uncorroded control specimens. This degradation appeared to increase as the corrosion level increases and as stirrup spacing as well as shear span to depth ratio decreases. First published online: 24 Aug 201

Experimental and Numerical Studies on Flexural Behavior of GGBS-Based Geopolymer Ferrocement Beams

The ferrocement structural concept has been shown to offer exceptional mechanical properties in terms of toughness, fracture control, and impact resistance, which are achieved by tight spacing and homogeneous reinforcement dispersion within the matrix. The flexure behavior of geopolymer ferrocement beams under axial flexural stress is being explored experimentally and computationally in this present work. Under flexural loads, nine samples of geopolymer ferrocement beams 150 mm thick, 75 mm wide, and 1700 mm long were tested to failure. The reinforcing steel bars and wire meshes, as well as the quantity of wire mesh layers, were the key factors studied. The initial crack load, ultimate failure load, and mid-span deflection with various loading phases, cracking patterns, energy absorption, and ductility index were all studied in relation to the behavior. In terms of carrying capacity, absorbing energy, and ductility, welded steel wire mesh beams fared better than other materials. Using ANSYS-19 software, nonlinear finite element analysis (NLFEA) was carried out to demonstrate the behavior of composite ferrocement geopolymer beams. The ensuing experimental and numerical data demonstrated that the degree of experimental value estimation supplied by the FE simulations was sufficient. It is crucial to demonstrate that, in comparison to control specimens, the increase in strength of specimens reinforced with tensar meshes was reduced by around 15%. Doi: 10.28991/CEJ-2023-09-03-010 Full Text: PD

The association between right ventricular function and exercise capacity for hypertensive patients

Background: Transthoracic echocardiography (TTE) would be used to evaluate right ventricular (RV) function in patients with arterial hypertension, and the link between RV dysfunction and exercise capacity was studied in the study population.Objective: To establish a correlation with exercise capability in the study group by using transthoracic echocardiography (TTE) to evaluate RV function in patients with arterial hypertension.Patients and Methods: Patients with hypertension were surveyed in a cross-sectional research; those known and treated; whether controlled or not and patients who were recently discovered to be hypertensive. Ninety patients were included; gender and age were taken into account. A thorough examination was performed on each patient (TTE) as well as six minute walking distance (6MWD). For all we had a written informed consent prior to enrollment. Results: Patients with untreated and uncontrolled hypertension showed significantly reduced right ventricular systolic and diastolic functions compared to those with well-controlled hypertension. Patients with untreated or uncontrolled hypertension had significant (P <0.001) deterioration on S', wave and diastolic dysfunction parameters (E/A, DTt, E/e t and IVRT). Untreated and uncontrolled hypertension patients showed a significant decrease in 6MWD compared to the well-controlled individuals (P <0.001). Conclusion: Untreated or ineffectively treated hypertension individuals had considerably reduced right ventricular function and exercise capacity, according to our findings. In the entire research population, right ventricular functions are strongly linked to exercise ability

Optimising surface roughness and density in titanium fabrication via laser powder bed fusion

The Ti6Al4V alloy has many advantages, such as being lightweight, formal, and resistant to corrosion. This makes it highly desirable for various applications, especially in the aerospace industry. Laser Powder Bed Fusion (LPBF) is a technique that allows for the production of detailed and unique parts with great flexibility in design. However, there are challenges when it comes to achieving high-quality surfaces and porosity formation in the material, which limits the wider use of LPBF. To tackle these challenges, this study uses statistical techniques called Design of Experiments (DoE) and Analysis of Variance (ANOVA) to investigate and optimise the process parameters of LPBF for making Ti6Al4V components with improved density and surface finish. The parameters examined in this study are laser power, laser scan speed, and hatch space. The optimisation study results show that using specific laser settings, like a laser power of 175 W, a laser scan speed of 1914 mm/s, and a hatch space of 53 µm, produces Ti6Al4V parts with a high relative density of 99.54% and low top and side surface roughness of 2.6 µm and 4.3 µm, respectively. This promising outcome demonstrates the practicality of optimising Ti6Al4V and other metal materials for a wide range of applications, thereby overcoming existing limitations and further expanding the potential of LPBF while minimising inherent process issues

Hybrid finite element–smoothed particle hydrodynamics modelling for optimizing cutting parameters in CFRP composites

Carbon-fibre-reinforced plastic (CFRP) is increasingly being used in various applications including aerospace, automotive, wind energy, sports, and robotics, which makes the precision modelling of its machining operations a critical research area. However, the classic finite element modelling (FEM) approach has limitations in capturing the complexity of machining, particularly with regard to the interaction between the fibre–matrix interface and the cutting edge. To overcome this limitation, a hybrid approach that integrates smoothed particle hydrodynamics (SPHs) with FEM was developed and tested in this study. The hybrid FEM-SPH approach was compared with the classic FEM approach and validated with experimental measurements that took into account the cutting tool’s round edge. The results showed that the hybrid FEM-SPH approach outperformed the classic FEM approach in predicting the thrust force and bounce back of CFRP machining due to the integrated cohesive model and the element conversion after failure in the developed approach. The accurate representation of the fibre–matrix interface in the FEM-SPH approach resulted in predicting precise chip formation in terms of direction and morphology. Nonetheless, the computing time of the FEM-SPH approach is higher than the classic FEM. The developed hybrid FEM-SPH model is promising for improving the accuracy of simulation in machining processes, combining the benefits of both techniques

Concurrent Acquisition of a Single Nucleotide Polymorphism in Diverse Influenza H5N1 Clade 2.2 Sub-clades

Highly pathogenic Influenza A H5N1 was first identified in Guangdong Province in 1996, followed by human cases in Hong Kong in 1997 1,2. The number of confirmed human cases now exceeds 300 and the associated Case Fatality Rate exceeds 60% 3. The genetic diversity of the serotype continues to increase. Four distinct clades or sub-clades have been linked to human cases 4-7. The gradual genetic changes identified in the sub-clades have been attributed to copy errors by viral encoded polymerases that lack an editing function, thereby resulting in antigenic drift 8. We report here the concurrent acquisition of the same polymorphism by multiple, genetically distinct, clade 2.2 sub-clades in Egypt, Russia, Kuwait, and Ghana. These changes are not easily explained by the current theory of “random mutation” through copy error, and are more easily explained by recombination with a common source. The recombination role is further supported by the high fidelity replication in swine influenza 9 and aggregation of single nucleotide polymorphisms in H5N1 clade 2.2 hemagglutinin 10