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FRCM (Fiber Reinforced Cementitious Matrix) is being used as a promising material in the field of reinforcement of masonry structures. Investigating the properties of FRCM can be a challenging task due to the intricate nature of its failure mechanisms. Typically, the tensile test, known for its simplicity and intuitive nature, serves as a common approach to assess FRCM properties. In this study, we present a novel non-linear analytical model designed to reproduce the tensile behavior of FRCM coupons. This model achieves this goal using only a minimal set of parameters while accounting for the various potential failure modes encompassing the mortar, interface, and fiber components. We validate the effectiveness of this analytical approach through a comprehensive comparison with experimental data. [ABSTRACT FROM AUTHOR]

There are some hybrid base isolation systems proposed to improve dissipated energy capacity of base isolation systems with different dissipation devices, for example shape memory alloy wires, ADAS dampers and slit steel dampers. In the present research, the novel hybrid seismic isolation system including seismic isolator with S-shaped steel dampers (SSSDs) is proposed and investigated to improve the energy dissipation capacity of the hybrid isolation system and decrease the displacement of the superstructure. Using finite element method, the numerical models of seismic isolator with S-shaped steel dampers are established and simulated under monotonic and cyclic loading tests. Based on the simulation data of seismic isolator with S-shaped steel dampers, mechanical properties of the novel isolation system are analyzed and compared, which can supple the practical application. [ABSTRACT FROM AUTHOR]

A simple limit analysis modeling for masonry arches with innovative strengthening is proposed in this paper, where the arch ring is discretized by rigid blocks according to the real bond pattern and the reinforcement effect is modeled through updating the failure surface of the contact joints. Considering all the extra force resultants provided by the reinforcement layer, we have first derived the constraints for the new yield condition and flow rule, defining the failure surface after applying the strengthening, and the new limit analysis formulation with consideration of reinforcement effect is then given. Such modeling is also very convenient to incorporate with sequential linear programming to solve non-associated problems. Applying the proposed theory, collapse analysis of an FRP-reinforced arch in 2D is presented and the results predicted from associated and non-associated formulations are compared. The results show that when analyzing the arch with reinforcement, the associated limit analysis may overestimate the ultimate load, as well as produce an incorrect collapse mechanism. Therefore, it is necessary to employ the non-associated flow rule for an accurate prediction of the collapse performance of reinforced arches. [ABSTRACT FROM AUTHOR]

Based on kinematics theory, this paper proposes a computational tool that can rapidly assess the damage mechanism of aggregates in masonry structures. In this approach, some pre-assigned local mechanisms are assessed on a three-dimensional (3D) model of the whole aggregate, on which the shape of the involved macro-blocks is directly modelled. The method uses the principle of virtual work to calculate the horizontal load multiplier, judge the local failure mechanism, and carry out the reinforcement design. The method realizes coding in AutoLIS language function, uses AutoCAD software to model, and then realizes operation. The case analysed in the paper is an example from the 17 masonry aggregates located in the historical centre of Arsita. This aggregate is referred to as "Il Torrione". [ABSTRACT FROM AUTHOR]

Steel-reinforced elastomeric isolators (SREIs) represent a widely adopted seismic isolation technique. However, their suitability for conventional residential structures, particularly in developing nations, is limited due to the associated high costs. This cost arises from the necessity of incorporating thick steel plates and substantial energy consumption during manufacturing. In contrast, fiber-reinforced elastomeric isolators (FREIs) present a novel elastomeric isolation solution. Rather than relying on steel lamina, FREIs utilize thin layers of fibers for vertical reinforcement. Compared to SREIs, FREIs offer a distinct advantage with their significantly reduced weight and the possibility of cost-effective manufacturing through cold vulcanization. FREIs can be installed between the upper structure and the foundation without the need for bonding or fastening, a configuration known as "unbonded application" resulting in substantial cost savings. Additionally, in scenarios without steel supports or with partial bonding, FREIs exhibit enhanced energy dissipation due to the friction generated between the isolator and the structure surfaces. This study presents a finite element analysis of FREIs, considering various shape factors and different boundary conditions (bonded, unbonded, and partially bonded). Each device underwent static analysis, experiencing a horizontal displacement of up to two times the overall height of the rubber pads while maintaining a constant vertical pressure. The outcomes of the study are assessed based on parameters such as horizontal maximum force, horizontal stiffness, horizontal frequency, and horizontal period. This numerical investigation offers valuable insights into the lateral response characteristics of FREIs. [ABSTRACT FROM AUTHOR]

In this paper, a theoretical scenario of charge transfer based on a modified quantum donor-acceptor model developed for the study and calculation of the efficiency of N719-TiO2 dye-sensitized solar cells DSSCs depends on the transition energy, current density and fill factor. The photovoltaic characteristics I-V of an N719-TiO2 heterojunction DSSC calculated based on current density using the software MATLAB program under the energy levels of both materials are assumed to be continuum levels. Transition energy is a critical role in calculation of I-V and efficiency of DSSCs. The characteristics of I-V of the N719-TiO2 device calculate using concentrations 3 × 1018 1/cm3 and 7 × 1018 1/cm3. The I-Vof the N719-TiO2 DSSC device reveal the electric properties and photovoltaic behaviour using the tert-Butyl alcohol solvent. An open-circuit voltage Voc is 0.8149 V, short-circuit current density ISc is 42.1987 mA/cm2, and fill factor of 0.271 at concentration 3 × 1018 1/cm3 under photo intensity 100 mW/cm2 at AM 1.5 to an overall conversion efficiency of 9.32%. While DSSC at concentration 7 × 1018 1/cm3showed Voc=0.8295 V, ISc=94.62 mA/cm2, and a fill factor of 0.286 to produce efficiency 22.44%. The current density, fill factor and efficiency increase with increasing the coupling constant and concentration carrier. It indicates the efficiency increase due to increased concentration and vice versa at limited transition energy. The higher efficiency of the N719-TiO2 device at higher concentrations led to suggest use application of N719-TiO2, low-cost, and high-performance solar cells. [ABSTRACT FROM AUTHOR]

Rubber is the basic material for some structural devices, such as seaport fenders and seismic isolators. In order to seismically isolate a structure, it is possible to interpose between the foundation and the superstructure a rubber device that increases the natural period of the structure. This feature reduces the damaging effect on building due to earthquakes. Several rubber pads typically constitute a seismic isolator interspersed with steel laminas or FRP. In this study, two rubber compounds for high damping elastomeric isolators have been proposed. The first is made of a natural rubber-bromobutyl blend (NR-BIIR), and the second is made of natural rubber and ethylene propylene diene monomer blend (NR-EPDM). They have been characterized through different experimental tests: tensile test, tear-resistance test, compression set, relaxation test, accelerated air oven aging, and hardness measurement. Furthermore, a finite element (FE) cyclic shear test analysis has been performed to evaluate the dynamic shear modulus and damping ratio. The results obtained have shown that the two rubber compounds are suitable for high damping elastomeric isolators. [ABSTRACT FROM AUTHOR]

In this paper, there are novel hybrid base isolation systems proposed to imrove the dissipated energy of the base isolation system with shape memory alloy (SMA) wires, ADAS dampers and slit steel dampers. Moreover, there are different shaped steel dampers due to low cost and simple fabrication which can be applied in dissipation system effectively and widely, such as X-shaped damper, J-shaped damper and U-shaped damper. Different steel dampers are analyzed to propose a novel hybrid seismic base isolation system. The novel hyrid base isolation system consisting of unbonded fiber reinforced elastomeric isolator (UFREI) and steel dampers is to be investigated further to improve the energy dissipation capacity of the base isolation system and decrease the displacement of the structure. [ABSTRACT FROM AUTHOR]

Elastomeric isolators are special devices for the seismic isolation of structures. They are typically made of alternating layers of steel or fiber-reinforced laminas and rubber pads. They are interposed between the ground and the foundation to increase the structure's natural period and reduce the damaging effect on the structure due to the earthquakes. This study proposes a detailed 3D FE modeling of fiber-reinforced elastomeric isolator (FREI), carried out through the FE software code Abaqus. The isolator understudy is constituted by several alternating layers of rubber pad made of a natural rubber-bromobutyl blend (NR-BIIR) and four GFRP laminas. In addition, it presents unbonded conditions to reduce production costs and allow its applicability in developing countries. So, the upper and lower edges do not exhibit any bond with the supports. The main feature of such a device is the large deformability thanks to the rollover deformation and the favorably lower lateral stiffness compared to the bonded isolator. [ABSTRACT FROM AUTHOR]

This paper adopts a very convenient 3D CAD method to quickly assess the seismic vulnerability of existing masonry towers. The study selected five typical collapse mechanisms, vertical splitting, base rocking, overturning with diagonal cracks (according to Heyman's approach on tilting towers), a combination of splitting and diagonal overturning and base sliding. The Zhongjiang South pagoda in China is selected as the research case. Basing on the principle of virtu-al works, assuming that masonry behaves as a small cohesion and frictional material, the collapse acceleration is calculat-ed with a direct manual procedure. The research results show that vertical splitting is the easiest collapse mechanism to appear, which is in full compliance with the results of the on-site survey carried out after the Zhongjiang earthquake, fur-ther demonstrating the reliability of this method. Such approach does not require complex mathematical foundations, can be easily mastered by non-professionals, and at the same time greatly reduces the amount of simulations/calculations, a feature which is helpful for the promotion of seismic research of masonry structures. [ABSTRACT FROM AUTHOR]

A kinematic limit analysis approach for three-dimensional curved rigid blocks is presented. To maintain the exact geometry of curved structures in a three-dimensional context, NURBS solids are used. Under the hypotheses of rigid elements and frictional behavior at interfaces, a kinematic limit analysis problem is defined and solved through a linear programming formulation. The Gothic arches in the Carmo convent, Lisbon (Portugal), are studied to prove the efficiency of the method. [ABSTRACT FROM AUTHOR]

The utilization of wastewater treatment technology today is not only to meet quality standards but also for reuse and recycling functions. One of them is by using granular active sludge (GAS) technology, which has many promising features due to its rapid deposition of biomass and large density, thereby reducing the need for land for deposition. In this study, GAS was made using activated sludge from a fecal sludge treatment plant after the aeration unit process. The activated sludge was seeded for 28 days with stirring at 20 rpm to create uniform conditions in the reactor and obtained an MLSS of 6720 mg/l. Then, a jar test was carried out to determine the dose of xanthan gum in the mud. The size of the GAS obtained was 1.8 mm after the granulation process has completed on day 29 with slow stirring in the reactor. when compared with sludge from water treatment plants obtained 0.6 – 1.2 mm. The formation of GAS was carried out in a sequential batch reactor (SBR). This paper is specifically made to see the effectiveness of chicken slaughtering waste treatment using GAS-SBR technology. [ABSTRACT FROM AUTHOR]

In Indonesia, there are various types of building construction, one of them is a building. A building structure is composed of several structural components, including beams. Therefore, structural planning is a very important factor and should be considered. Advances in construction technology in today's modern era, also accompanied by the increasing use of concrete in the construction world, making prestressed concrete can be used as one of the best options and solutions to meet concrete needs. In designing a structure there are several principles that must be considered like strength, stiffness and stability. One of the factors that must be considered in the construction of prestressed concrete is the parameter of Flexural Capacity, to make sure the beam is strong enough to carry the bending load and in the range of allowable stress. Therefore, an analysis of the flexural capacity of the prestressed T-beam was carried out using the software RCCSA (Reinforced Concrete Cross Analysis) V4.3 and Response2000. The beam model used has three types of cross-sections which have the same area of 260000 mm2. Variables carried out in this journal are 1) reinforcement ratio 2) the stress value applied to the tendon. The flexural capacity in the cross-section is calculated without taking the stresses that occur in the beam due to external loads. This research is expected to analyze and compare the flexural capacity of prestressed T-beams using RCCSA V4.3 and Response2000 software, Analyze and compare the effect of variations in the ratio of non-prestressed reinforcement to the flexural capacity of the prestressed T-beam concrete section, Analyze and compare the effect of variations in the pre-strain value on the flexural capacity of the prestressed T-beam concrete section. From the results of this study, prestressed T-beams with a larger reinforcement ratio have the greater flexural capacity in range of 15.2% - 25.2%, but accompanied by a decrease in cross-sectional ductility in range of 15.4% - 100%. [ABSTRACT FROM AUTHOR]

A 3D numerical model based on finite differences is proposed to predict the degree of vulcanization of a Fiber Reinforced Elastomeric Isolator FREI constituted by five EPDM pads and four GFRP laminas interposed between contiguous pads. EPDM used is composed by 2/3 of regenerated rubber and 1/3 of virgin rubber. A prototype is cured at 130°C for 40 minutes and shore A hardness is measured in the central cross section on two points, the first located in the middle, the second near the corner. It is found that the crosslinking density obtained is suboptimal (but still acceptable for an engineering point of view) and that it is required to increase the vulcanization temperature to 150°C to obtain a full and homogeneous curing. [ABSTRACT FROM AUTHOR]

garlic is one of the important horticultural commodities and high economic value product. Low garlic production rate is influenced by various factors like weather, agroecological conditions, varieties, and cultivation techniques used. The low production of garlic besides caused by decreasing in the planted area as well as a high disturbance of pests. Alternaria porri (Ellis) Cif. is a fungus that causes purple spots on garlic plants. This disease results in significant losses for farmers. Yield losses caused by their infection can reach 50 - 57% even causing crop failure. This study aims to determine the intensity of the purple spot disease in five varieties of garlic. This research has been conducted at the Research Institute Vegetable Plants (BALITSA) from December 2019 to April 2020. This research method uses randomized block design, consisting of five treatments, they are Sangga Sembalun, New Tawangmangu Baru, Lumbu Putih, Lumbu Kuning, and Lumbu Hijau. The result of the research indicated that the Lumbu Putih variety has the highest disease intensity compared to other varieties, while Lumbu Kuning shows the lowest intensity. [ABSTRACT FROM AUTHOR]

Externally bonded composites have become an effective alternative for building strengthening in recent years, such as FRP (Fiber Reinforced Polymer) and FRCM (Fiber Reinforced Cementitious Matrix) can be utilized in this retrofitting strategy. For masonry structure, curved members are very common and tend to be the weakest parts of the system, exhibiting bond behavior different from that of flat surfaces. In this article, a simplified model consisted of an elastic composite strip and inelastic brittle substrate was adopted, based on which a fully analytical approach is developed for describing the debonding mechanism of FRP/FRCM strengthened curved surface under shear force. This approach requires few parameters, and can be realized with limited computational cost in a standard MATLAB environment, while providing a stable solution. This approach was then validated against numerical method and experimental data available in literatures, proving its effectiveness and reliability. [ABSTRACT FROM AUTHOR]

In recent years, strengthening with Fiber Reinforced Polymers (FRPs) has emerged as an effective way for the structural upgrading of masonry elements. In such typology of external reinforcement, the bond quality is crucial for the increase of the load bearing capacity. The bond efficacy beyond the elastic limit can be studied analytically or numerically via several different models, where the most important issue to tackle is the reproduction of the typical brittle behavior of the substrate. In this paper, a simple numerical approach which models FRP as elastic and lumps all non-linearities on the FRP/masonry interface is proposed. The non-linear behavior of such interface is modeled in a simplified but effective way integrating numerically the differential equations deduced from equilibrium and compatibility (once that a non-linear constitutive relationship between tangential stress and slip is assumed at the interface). Such integration is carried out by means of a particularly simple forward scheme that requires the estimation of the slip value and its derivatives on specific knot points. A comparison against existing literature indicated that the proposed numerical procedure can adequately reproduce global load-displacement curves in standard single lap shear tests, as well predict the local slip behavior. [ABSTRACT FROM AUTHOR]

The vulnerability of masonry structures, especially when subjected to a changing of the load and boundary conditions, was evident since the antiqueness when the first interventions of reinforcement were designed. Lately, with the easy provision of innovative materials, the upgrade of the structural performance is often accomplished through the application of composite systems as FRP (fiber reinforced polymer) and TRM (textile reinforced mortar). In TRM systems, fibers having a high strength under tensions are embedded within an inorganic matrix. The wide range of materials (carbon, PBO, glass, basalt) that the industry put at disposal makes difficult a correct definition of the efficacy of such kind of reinforcement technique. Indeed, the literature showed the several failure typologies that can be encountered when a masonry element is reinforced with TRM. In the case of arches and vaults, the curvature itself complicates furthely a correct prediction. The paper wants to provide a reasonable way to model numerically curved masonry structures reinforced with TRM and explore the advantages and detriment of advanced simulation and simplified approaches. [ABSTRACT FROM AUTHOR]

The article compares two numerical approaches with different levels of details used to simulate curved masonry supports subjected to single lap shear tests. The masonry pillars were strengthened on the extrados and on the intrados with TRM materials comprising a 100 mm wide PBO textile embedded into 10 mm thick mortar layer. The numerical analyses were carried out using two approaches: a heterogeneous micro modelling FE approach and a spring model approach. The first modelling strategy was developed using the commercial software Abaqus and it involved the separate modelling of the constituent materials (i.e., bricks and mortar joints) as well as the simulation of the PBO textile and mortar matrix. The second approach was specifically developed to analyze curved supports and it comprised the adoption of equivalent normal and shear springs used to model the components of specimens (support, matrix and reinforcement) and, moreover, the interface between reinforcement and matrix. It is worth mentioning that this numerical investigation is part of an ongoing experimental and numerical work focused on analyzing the effect of curved brittle supports on the adherence properties of innovative strengthening materials (i.e., FRPs) and herein extended to the adoption of TRM composites. In absence of a comprehensive experimental characterization of the TRM constituent materials, the mechanical properties of the textile and mortar matrix were deduced from available data provided by the manufacturer. The numerical results are herein presented and critically compared in terms of global force-displacement curves and damage maps obtained at the end of the simulations. [ABSTRACT FROM AUTHOR]

The article presents the results obtained by using an analytical model herein slightly modified to study Near Surface Mounted (NSM) CFRP strengthening applied to brittle supports. To this scope, three sets of lab investigations comprising CFRPs applied to concrete and masonry pillars were considered. The lab investigations comprised testing of different CFRP strips characterized by various geometrical (cross section and bonding length) and mechanical parameters (elastic modulus). The interfacial tau-slip laws adopted in the analytical model were tuned using available experimental data and idealized bilinear laws proposed by the authors in the experimental campaigns. The reliability of the model was assessed by comparing the global force-slip curves obtained experimentally and analytically. Also, the analytical model allowed estimating the axial stress in the FRP strengthening, providing valuable information about the most probable failure mode (i.e., debonding or fiber failure). A global satisfactory agreement was found in all the set of tests studied with the proposed model. The analytical approach was able to accurately estimate the initial stiffness, peak load and post peak behavior. [ABSTRACT FROM AUTHOR]

Rubber recycling technology has been a popular issue in many research fields considering huge amount rubber waste in the environment. This paper discusses an application of reactivated ethylene propylene diene monomer (EPDM) to fabricate fiber reinforced elastomeric isolators (FREIs), which is considered as a low cost seismic protection device. Two types of regenerated EPDM are considered to be blended with two different virgin rubber, Vistalon 3666 and Dutral 4038. The first is used to produce a compound with the hardness around 30 Shore A, while the latter 60 Shore A. A series of experimental tests are performed including rheometer, shore A hardness, compression set and uniaxial tensile test. The results show that the compounds with reactivated EPDM type B present the most satisfactory performance, before and after ageing. This paper discusses also the method in fabricating FREIs, made of the selected recycled rubber and the glass fiber reinforced polymer (GFRP). The hardness test performed on the sliced FREI specimen indicates that the vulcanization temperature used in the production is roughly suitable to obtain the expected rubber properties. [ABSTRACT FROM AUTHOR]

The vulcanization process of a low cost parallelepiped seismic rubber isolation device is studied from a numerical standpoint. The seismic isolator is constituted by few rubber pads made by regenerated rubbed and EPDM and -instead of steel laminas-GFRP sheets are utilized to reduce further the production cost. Such cheap device, assuming also its installation without head and foot connecting steel plates, is particularly suited for the isolation of low rise masonry buildings in developing countries. A refined FE discretization is utilized to predict the temperature-time histories that each point of the device exhibits during a standard vulcanization in an industrial oven. The knowledge of the temperature profiles is mandatory to predict the local final vulcanization degree, once that a suitable vulcanization model is at disposal. From simulations results, it is found how the utilization of steel laminas-thanks to their high thermal conductivity-allows a much faster and homogeneous vulcanization inside the bulk, whereas the introduction of pultruded GFRP sheets is equivalent to the vulcanization of a single thick rubber pad. As a consequence, in this latter case there is the need to extend curing to long vulcanization times, always associated to over-vulcanization of the skin and under-vulcanization of the core. [ABSTRACT FROM AUTHOR]

This paper presents a series of experimentations and numerical modeling to evaluate the damping of rubber for seismic isolation purposes. A cyclic shear test is considered as a standard procedure to evaluate the damping of rubber materials. However, there is another method to evaluate the viscous damping of rubber by means of relaxation test that requires only small dumb-bell specimens of rubber, using a uniaxial tensile test device. This method allows an efficient procedure in examining the mechanical characteristic of rubber for seismic isolation purposes. This paper evaluates such a procedure to characterize the mechanical properties of a low damping rubber. The result shows that the proposed procedure presents a good prediction of the mechanical properties of the rubber. [ABSTRACT FROM AUTHOR]

Thick rubber pads for cheap isolation of low rise buildings require an optimal vulcanization along the thickness. The present paper is aimed at presenting an integrated three-step approach for the optimization of curing in presence of items exhibiting considerable thickness. It requires a preliminary standard experimental characterization in a rheometer, conceived to tune a simple kinetic steady-state model finally nested into a Finite Element FE heat transmission code, which allows to simulate the curing process in full 3D heat transmission problems. The kinetic model is a phenomenological approach based on 3 kinetic constants, aimed at predicting the initial curing rate, maximum crosslinking and reversion. Kinetic constants are deduced fitting normalized experimental rheometer curves. FE transient curing computations are carried out on a thick rubber pad, used for the production of unbonded low cost seismic isolation devices. The entire 3D geometry is discretized with a refined mesh, in order to realistically reproduce the vulcanization occurring in an industrial mold. From simulation results, interesting design considerations can be drawn, allowing to establish time and temperature of curing as a function of the rubber thickness and chemical composition. [ABSTRACT FROM AUTHOR]

Base seismic isolation is an efficient technical solution to reduce the vulnerability of new and existing structures. However, commercial isolators are usually expensive due to the need for high damping rubber and thick steel plates. In this work, a recycled rubber material derived from industrial waste is used for rubber pad fabrication to reduce the cost. Two compositions of recycled rubber are introduced to find the optimum choice. A series of uniaxial tensile test and relaxation test is conducted to characterize the hyperelasticity and viscosity of the recycled rubber. The specimens are performed both in fresh and aged condition to evaluate its durability. The aforementioned recycled rubber pad is used to fabricate an unbonded fiber reinforced elastomeric isolator, which is well known as a cheap form of the base isolation system. Finally, the use of recycled rubber for base isolators is promising regarding the rupture behavior and durability of the material under ageing condition. [ABSTRACT FROM AUTHOR]