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Gastro-retentive drug delivery systems plays a significant role in delivery of drugs with narrow absorption window by following plethora of versatile approaches such as high-density system, muco-adhesive system, low density system, super-porous hydrogels, and floating systems to enhance the bioavailability in upper part of stomach. The recent research work was focused on floating system in which different combination of polymers and lipids were used to synthesize the floating microparticles that remain buoyant over the gastric fluid for 24 hrs.Solvent diffusion evaporation method was adopted by using various polymers such as ethyl cellulose, stearyl alcohol, gelucire 43/01, Eudragit E100 and tween 80 as surfactant. Eudragit E100 was used in different concentrations to modulate the release pattern. Furosemide was selected as a model drug due to has narrow absorption window in GIT. Furthermore, characterization was carried out by analysis the percent recovery of microparticles, furosemide loading, in-vitro release studies, SEM, DSC, XRD, FTIR, particles size analysis, optical microscopy.Around 88% encapsulation efficiency of microparticles were obtained which was free flowing. Particle size of microparticles containing stearyl alcohol was from 363.3±120 to 400±204.41 µm and containing gelucire 43/01 was from 216±106 to 296.7±106 µm.Controlled drug release was accomplished by the addition of hydrophilic polymer Eudragit E100 which forms the pores on the surface of microparticles. In addition, pores on the surface of microparticles due to Eudragit E100 were assessed by SEM. DSC, XRD and FTIR confirmed the absence of drug polymer interaction and amorphous form of drug after encapsulation. Drug release kinetics was determined by applying the different models such zero-order model, first order model, higuchi and korsemeyer-pappas model. All formulations followed the korsemeyer-peppas model at 1.2 pH.In vivo study will be performed in future to accomplish better results regarding bioavailability of drug loaded microparticles.

The improvement in the compressive strength (CS) and ductility of plain concrete always remained an active area for advanced research. The present study aims to enhance the strength of low strength hybrid fiber reinforced concrete (HFRC) cylinders confined with different number of carbon fiber reinforced polymer (CFRP) sheets by examining the axial CS, axial compressive strain, and compressive stress–strain behavior of low strength HFRC cylinders confined with CFRP sheets. The HFRC consisted of steel fibers and polypropylene fibers. Two groups of low strength HFRC specimens (12.5 MPa and 16.5 MPa) were fabricated to investigate the effect of CFRP confinement on the different CS of HFRC. The experimental outcomes depicted that the lateral CFRP confinement of concrete significantly improved the CS, axial compressive strain, and axial stiffness of low strength HFRC specimens. The improvements of 115.7% and 130.7% occurred in the CS of 12.5 MPa group for single and double CFRP layers, respectively. Similarly, the improvements of 37.4% and 112.6% occurred in the CS of 16.5 MPa group for single and double CFRP layers, respectively. Therefore, the CFRP confinement is more effective for low strength HFRC as compared with high strength HFRC in terms of axial CS and axial compressive strain.

The aim of this paper is to advance the research on the use of alkali-activated fly ash in recycled concrete aggregate (RCA) bearing mortar (RAM) to achieve low carbon footprint and sustainability in construction. To this end, the present paper explores the advantages in terms of improved properties of RAM by incorporating fly ash with an alkali-silicate activator. Results of testing reveal that compressive strength of RAM is improved by more than 30% by using 20% fly ash with 3–6% silicate-activator. RAM with activated-fly ash showed significant improvement in resistance against water absorption, chloride penetration, and acid attack. The durability parameters are fairly correlated with the compressive strength: improvement in durability performance is noticed with increasing compressive strength, indicating that microstructural developments that yield high mechanical strength also contribute to improvement in durability.

The literature is deficient for the theoretical predictions of the axial loading capacity of Fiber Reinforced Polymers (FRP) reinforced concrete-filled FRP tube (CFFT) columns. The present study aims to propose new models for predicting the axial loading capacity of FRP reinforced CFFT columns. Two types of FRP bars were used in this work: one is glass fiber reinforced polymer (GFRP) bars and the second is carbon fiber reinforced polymer (CFRP) bars. Two different databases were developed from the previous experimental works. One of the databases consisted of experimental results of 500 FRP-confined concrete compression members and the second database consisted of experimental results of 279 FRP-reinforced concrete columns. An empirical model was proposed for the axial load-carrying capacity of FRP-reinforced CFFT columns using these databases. For the comparative study, a nonlinear finite element model (FEM) was simulated for FRP-reinforced CFFT columns using concrete damaged plastic (CDP) model. A detailed parametric study was also performed using the proposed FEM to investigate the effect of various parameters of studied specimens. A close agreement was observed between the proposed empirical and numerical models.

Despite plain cement concrete presenting inferior performance in tension and adverse environmental impacts, it is the most widely used construction material in the world. Consumption of fibers and recycled coarse aggregates (RCA) can add ductility and sustainability to concrete. In this research, two mix series (100%NCA, and 100%RCA) were prepared using four different dosages of GF (0%GF, 0.25%GF, 0.5%GF, and 0.75%GF by volume fraction). Mechanical properties namely compressive strength, splitting tensile strength, and flexural strength of each concrete mixture was evaluated at the age of 28 days. The results of testing indicated that the addition of GF was very useful in enhancing the split tensile and flexural strength of both RCA and NCA concrete. Compressive strength was not highly sensitive to the addition of GF. The loss in strength that occurred due to the incorporation of RCA was reduced to a large extent upon the inclusion of GF. GF caused significant improvements in the split tensile and flexural strength of RCA concrete. Optimum dosage of GF was determined to be 0.25% for NCA, and 0.5% for RCA concrete respectively, based on the results of combined mechanical performance (MP).

Recycled coarse aggregates (RCA) and fly ash (FA) are materials with least to very low global warming potential. Considering long term strength and durability, various studies have suggested to use RCA in concrete with FA. This research paper deals with the strength and economic performance of concrete made with individual and combined incorporation of FA and RCA. Nine different mixtures of concrete were prepared by varying the incorporation levels of RCA and FA. 0% RCA, 50% RCA and 100% RCA were used in concrete with three different levels of FA (0%FA, 20%FA, and 40%FA). The compressive strength of each mixture of concrete was determined at the age of 3, 28, 90 and 180 days. To evaluate economic performance cost of 1 m3 of each mixture of concrete was compared to that of the control mixture having 0% RCA and 0% FA. Results showed that RCA was detrimental to the compressive strength of concrete at all ages, whereas, FA reduced early strength but improved the strength at later ages of testing i.e. 90 and 180 days. FA plus RCA mixes also showed lower early age strength but gained higher strength than conventional concrete at the age of 180 days. RCA did not reduce the cost of concrete effectively. FA despite having a very high transportation cost, it reduced the cost of concrete efficiently. FA did not only reduce the cost of binder but also lower the demand of plasticizer by improving workability. Cost to strength ratio (CSR) analysis also indicated that FA significantly improve the combined economic and strength performance of RCA concrete mixes.

This paper studies the impact of replacing natural coarse aggregates (NCA) with recycled coarse aggregates (RCA) and cement (OPC) with fly ash (FA), on properties and economy of concrete. RCA was obtained by crushing old concrete specimens. FA of low calcium type was used to partially replace OPC. A total of nine concrete mixes (including a reference mix) were prepared using 50% RCA, and 100% RCA with four different levels of FA (0% FA, 10% FA, 20% FA, 30% FA). Workability, fresh density, compressive strength, apparent porosity, and bulk density was measured to evaluate the performance of each mixture. Mixes with optimum levels of both RCA and FA reaching the compressive strength potential of reference mix at 90 days, were subjected to chloride migration testing. To ascertain the combined impact of RCA and FA on economic and strength performance of concrete, a cost to strength ratio (CSR) analysis was also performed on all mixes. Results of testing indicate that FA compensates the loss in workability of fresh concrete and improve the compressive strength of RCA concrete at 28 and 90 days. Negative influence of RCA on density and porosity is minimized by consumption of FA in concrete. Mixes with 50% RCA and 20–30% FA show better resistance against chloride penetration compared to that of the reference mix. CSR analysis suggests that FA must be used along with RCA in concrete in order to minimize the negative influence of RCA on both cost and strength.

© The Author(s) 2018. This paper explores a model predictive control (MPC) strategy with constraints satisfaction for a high power induction heating load. The MPC predicts the state variables and future control sequence of the system in advance and achieves on-line-optimization with a reduced error. The state-space model of the system with a parallel resonant load is developed and then MPC is applied. The proposed approach controls the DC link current at the rectifier output and reactive component of the supply current. The DC current is used to regulate the power of the heating load and the reactive component of input current is kept at zero to attain the unity power factor. The results show that the proposed strategy regulates the power of the heating load, achieves unity power factor at input of the system and handles the variables within the defined constraints effectively.

The model predictive control (MPC) technique for a solar-based series-resonant inverter conventionally used in domestic heating is explored. The photovoltaic energy system (PVES) converts the solar energy into electrical energy where DC voltages of different cells are linked at a common bus. A Cuk-converter is used to interface the PVES with the DC load bus and the heating inverter. These heating inverters are replacing gas cookers in restaurants, guest rooms, and domestic- and commercial-kitchens for cooking of various foods. A number of control algorithms have been employed to control the power of the heating inverter but they have certain limitations; especially they do not predict the future response of the circuit. The MPC, an advanced control approach, has the potential to estimate the future behaviour of the model in a predictive manner. Hence, to control the power of the resonant inverter connected with a 3.36 kW heating load, MPC is applied. The simulation results verify the validity of the power control of a solar-based series-resonant inverter using the MPC algorithm.

The use of fly ash as a cement replacement material brings economy and sustainability in the concrete construction. Despite economic and environmental benefits, fly ash incorporation in concrete reduces its early age performance. Therefore, the main objective of this research is to increase the incorporation level of fly ash in the hybrid binder (cement plus fly ash) utilizing the sulfate activation technique to overcome the issue of inferior performance at an early age. Replacement levels of fly ash with cement were kept as 20 %, 40 %, and 60 %. 2 % sodium sulfate (Na2SO4) by weight of binder was utilized as an activator. Compressive strength and flexural strength tests on standard samples were carried out at the age of 3, 28 and 90 days. Durability tests namely apparent porosity, sorptivity coefficient and chloride penetration tests were also conducted. Experimental results showed sulfate activation increased the early age strength at all levels of fly ash. After activation, concrete mix with 20 % and 40 % fly ash showed better strength performance than that of the conventional concrete at all ages. Concrete with 20 % and 40 % fly ash upon activation showed lower sorptivity and porosity than control mix at all ages. Similarly, chloride penetrations of concrete with 20, 40 and 60 % activated fly ash was noticeably lower than that of the control concrete. Chemical activation is also beneficial in reducing the cost and carbon footprint per unit strength of the fly ash mixes.

This paper explores Laguerre functions based model predictive control (MPC) of a current-source resonant inverter extensively used in induction heating applications. The classical MPC can be applied in these inverters but the main drawback of MPC is its weighty mathematical iterations. Hence, Laguerre functions based MPC approach is proposed in this work. The state space method is used to develop the proposed strategy. The Eigen values of the proposed controller are compared with the discrete-time linear quadratic regulator (DLQR). The Laguerre based MPC approach is then applied for the power control of the heating load.