Percentage Of Water Uptake Research Articles

Influence of Adding Lignin and Wood as Reactive Fillers on the Properties of Lightweight Wood–Polyurethane Composite Foams

Abstract In this study, bio-based rigid polyurethane (PU) composite foams were prepared by a free-rising method, with the addition of wood particles (10 and 20 weight percent by the foam mass) and kraft lignin (5 and 10 weight percent by the polyol mass) as reactive reinforcing fillers. The resultant PU composites were evaluated for chemical structure, density, morphology, compressive properties, water uptake, and thermal stability. Fourier-transform infrared analysis confirmed the formation of characteristic urethane bonds in all foam samples. The foaming process was slowed down by the incorporation of lignin and wood particles. The apparent density of lignin-incorporated wood–PU composite foam ranged between 77 and 105 g/cm3. Compared with the neat PU foam, addition of wood particle resulted in decreased compressive properties and increased water uptake of the foams, whereas incorporation of lignin had a positive effect on the compressive properties and water resistance. In general, the PU foam sample with the incorporation of only 5 percent lignin (PUL5) exhibited the optimal physical–mechanical properties, with the compressive strength increased by 74 percent and 24-hour water uptake decreased by 28 percent compared with the control PU foam. Thermogravimetric analysis showed that the incorporation of lignin and wood particles did not significantly affect the thermal degradation pattern of foam but rather increased the mass of char residue.

Preparation and characterization of vancomycin-loaded chitosan/PVA/PEG hydrogels for wound dressing

This study describes a drug-loaded porous hydrogel for delivery of vancomycin. Hydrogels based on chitosan (CS), Polyvinyl alcohol (PVA) and Polyethylene glycol (PEG) were prepared by lyophilization. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and fourier transform infrared (FTIR) spectroscopy were used to characterize the structures. Water uptake percentage and vancomycin release were also measured. The antibacterial activity against Staphylococcus aureus was investigated. According to the results, mean pore diameter (MPD) was decreased by addition of PEG and reached to 1.3 ± 0.5 μm. On the other hand, 43% decrease in water content of the hydrogels showed along with the incorporation of PEG. The inhibition zone confirmed antibacterial effect of the vancomycin-loaded hydrogels. The porous CS/PVA/PEG hydrogels containing vancomycin could be good candidates to potentially be used as wound dressing.

Physical properties of impregnated sengon wood by monoethylen glycol and nano silica from betung bamboo sticks

Sengon wood (Falcataria moluccana) is a fast-growing species that has low dimensional stability and density. The purposes of this study were to analyze the effect of impregnation treatment by using MEG (monoethylen glycol) and nano silica from betung bamboo sticks on the dimensional stability and density of sengon wood and to identify the characteristics of impregnated sengon wood. The treatments were consisted of untreated (water treated), 50% MEG (MEG), 0.5% nano silica in 50% MEG (MEGsilica 0.5%), 0.75% nano silica in 50% MEG (MEGsilica 0.75%) and 1% nano silica in 50% MEG (MEGsilica 1%). Weight percent gain, anti-swelling efficiency, water uptake, bulking effect, and density were affected by the treatments. It was due to the coverage of MEG and nano silica on cell walls and vessels of sengon wood (SEM analysis). Also, the presence of nano silica in wood treated (SEM-EDX analysis). The cristalinity of sengon wood decreases because MEG is amourphous. FT-IR showed there was no MEG bonds with sengon wood cell wall components or between nano silica and sengon wood. The optimum treatment for sengon wood was MEGsilika 1%.

23 Full Factorial Design for Formulation and Evaluation of Floating Oral In Situ Gelling System of Piroxicam

Piroxicam is an NSAID (non-steroidal anti-inflammatory drug) persisting antipyretic and analgesic effects and being usually implied in managing and treating osteoarthritis, rheumatoid arthritis, soft tissue disorders, ankylosing spondylitis, and acute gout and also in post-operative pain management. The present research was undertaken aiming to formulate Piroxicam encompassing floating oral in situ gels, in order to augment its anti-inflammatory activity and to alleviate its gastric ulceration potential. In the present work, a three-factor at two-level (23) factorial design was adopted to inspect the effects of three factors viz. sodium alginate [A], sodium bicarbonate [B], and sodium citrate [C] on the dependent variables like in vitro gelation, in vitro floating, percentage water uptake, and percentage drug release. All the formulations have exhibited pH ranging from 6.7 ± 0.25 to 7.4 ± 0.24. Percentage drug content was noted in the range of 96.3 ± 0.27 to 99.5 ± 0.28%. In vitro gelation was instantaneous post administration of the system, which remained intact for an extended time period. Percentage water uptake was in the range 9.01 ± 0.15 to 31.01 ± 0.25%; floating lag time was estimated around 7 ± 0.39 to 57 ± 0.36 s. Formulations F4 and F5 reflected floating even past 12 h. All the formulations have exhibited drug release of around 90% within 8 h. It was experiential that the chosen independent variables had significant effect on the dependent variables, justifying the robustness and aptness of design implied for optimization. The developed system may be a promising and alternative strategy to augment gastric retention of Piroxicam, thereby increasing its therapeutic efficacy. It even offers additional benefit of reducing the gastric irritation, tissue damage, and ulceration, by avoiding direct contact of drug with mucosa of stomach.

Synthesis and characterization of poly 2‐ N ‐acrylamido‐2‐methyl−1‐propane sulfonic acid functionalized graphene oxide embedded electrolyte membrane using DOE for PEMFC

A novel proton exchange membrane consisting of 2-N-acrylamido-2-methyl−1-propane sulfonic acid modified graphene oxide nanocomposite (PAMPS-mGO), carboxylated poly(vinyl chloride) (CPVC), and poly 2-N-acrylamido-2-methyl−1-propane sulfonic acid (PAMPS) has been successfully prepared by simple and scalable polymer blending methodology. Different compositions of PEM in terms of its constituting precursors such as PAMPS-mGO, CPVC, and PAMPS were optimized by Placket Burman Design and their ion exchange capacity (IEC), oxidative stability, water uptake percentage, mechanical stability, and proton conductivity were evaluated. The amounts of significant precursors were further optimized by Central Composite Design. The membrane with excellent performance in PEMFC was obtained when appropriate proportions of CPVC (10%), PAMPS (20%), and PAMPS-mGO (20%) were blended. Among all membrane with mentioned composition exhibited IEC 1.3 mmol/g, oxidative stability 97.2%, WU 40.8%, proton conductivity 151 S/cm, water content 17.43, current density 1537 mA/cm2 at 120°C, power density 566.5 mW/cm2 at 120°C, Young modulus 797 MPa, tensile strength 16.8 MPa, and elongation at break % of 2.7 MPa. These results are in good comparison with PEM based on Nafion. Thus, the CPVC, PAMPS, and PAMPS-mGO-based composite PEM is a good candidate for PEMFC at elevated temperature under anhydrous conditions.

Effects of Plasticizers and Clays on the Physical, Chemical, Mechanical, Thermal, and Morphological Properties of Potato Starch-Based Nanocomposite Films.

Biodegradable polymeric films have great potential as alternatives to synthetic polymeric films to reduce environmental pollution. Plasticizing agents and nanofillers can improve the mechanical properties of polymer-based composites, resulting in materials with better flexibility and extensibility. Starch, a natural polymer, can be produced at low cost and on a large scale from abundant and inexpensive agricultural resources like potatoes. The aim of the present work was to fabricate mechanically strong and thermally stable potato starch films reinforced with different types of plasticizers and nanoclays at different concentrations. Different types of plasticizers such as water, glycerin, ethylene glycol, sorbitol, and formamide and three types of clays such as montmorillonite, hectorite, and kaolinite at various concentrations were used to prepare potato starch-based nanocomposite films. The films were prepared using a very simple solution casting process. The mechanical properties and thermal stabilities of nanocomposite films significantly improved using montmorillonite, hectorite, and kaolinite clays. The water uptake percentage of the fabricated films decreased with addition of plasticizers and further decreased with addition of different types of clays. The structural and morphological changes of the fabricated films in the presence of plasticizers and nanoclays were correlated in detail with their mechanical properties, crystallinity, biodegradability, thermal stability, and water absorption capacities.

Synthesis and characterization of a novel poly (vinyl alcohol)-based zinc oxide (PVA-ZnO) composite proton exchange membrane for DMFC

Electrolyte polymeric membranes were synthesized by impregnating zinc oxide (ZnO) nanoparticles (NPs) in a cross-linked PVA matrix for Direct Methanol Fuel Cell (DMFC) applications. The novel membranes consist of PVA as the support while zinc oxide nanoparticles serve as inorganic ion exchangers. The fabricated composite proton exchange membranes exhibit a wide variety of advantages which include good thermal and chemical stability. The synthesized membranes demonstrate a high percentage of water uptake (85%–105%) and a low percentage of methanol uptake (17%–21%). Other important properties such as transport number (0.88) and ion exchange capacity (0.78 meq.g−1) were also determined, and they were found comparable to Nafion®117. Ionic conductivity (3.9 mS/cm) of the composite membranes was determined and found comparable to other PVA based composite membranes reported in literature. Characterization of the membranes was carried out using Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDX) and Thermogravimetric analysis (TGA). These characterizations revealed the structural interaction between the support and the ion exchanger, crystalline nature, surface morphology, elemental analysis and the thermal stability (upto 280 °C) of the membranes, respectively. The mechanical characterization of the membranes was also carried out on a Universal Testing Machine (UTM), revealing satisfactory mechanical stability. The results demonstrate the possibility of synthesis of a low-cost proton exchange membrane for DMFC applications.

Water availability effects on germination, membrane stability and initial root growth of Agave lechuguilla and A. salmiana

Water availability during seed germination and seedling development is critical to plant development and establishment. The aim of this study was to determine the effects of four water potentials (ΨW) (−0.03, −0.48, −1.19 and −2.04 MPa) on seed germination, seedling root growth and root membrane stability of Agave lechuguilla Torr. and A. salmiana Otto ex Salm-Dyck. to explain the paradoxical situation of vegetatively propagated species producing large quantities of seeds in a dry climate. The results showed that seed water uptake and germination percentage were significantly lower at −1.19 and −2.04 MPa than at −0.03 MPa. The time to reach maximum seed germination increased at low ΨW. The final root length and root growth rate were higher in A. salmiana than in A. lechuguilla and decreased at ΨW of −1.19 and −2.04 MPa. Both Agave species increased root electrolyte leakage at ΨW of −1.19 MPa, which suggests changes in membrane integrity and stability in response to the water deficit. These germination and initial root growth responses could ensure the establishment of both Agave species during the rare periods with sufficient moisture availability and allow them to tolerate initial periods of low water availability, although with low establishment probability.

Influence of organoclay on behaviour of polylactic acid (PLA)/polypropylene (PP) blend

In this study, thermoplastic composite by blending of Polylactic acid (PLA) and Polypropylene (PP) was prepared with fixed ratio of 75:25 % by weight. Varying content of organoclay were studied with different loading of 1, 3, 5 and 7 wt.% in order to study the potential of this nanofiller in the composite. The composites were prepared by using twin screw extruder. Characterizing of PLA/PP-Clay (PLA/PP-C) composites were analyzed by focusing on physical, thermal and morphological properties. Water absorptions was analyze to observe the percentage of water uptake when percentage loading of organoclay added were increased. Differential scanning calorimetry (DSC) was performed to analyze the thermal stability and thermal sensitivity of the composite. Meanwhile, x-ray diffraction (XRD) were observed to study the fracture surfaces of PLA/PP-Clay composites. In water absoptions analysis it was found that the percentage of water uptake were decreased when organoclay added at 7 wt.%. DSC results showed that melting temperature (Tm) were decreased when the loading of organoclay increased and the thermal stability was improved by addition of organoclay. Morphological analysis by XRD showed that exfoliation and intercalation happened in the system. It is suggested that these combination of PLA/PP-Clay have a good potential for the fabrication of nanocomposites.

Gamma irradiation-induced grafting of 2-hydroxyethyl methacrylate (HEMA) onto ePTFE for implant applications

The extreme hydrophobicity of expanded polytetrafluoroethylene (ePTFE) hinders bone-tissue integration, thus limiting the use of ePTFE in medical implant applications. To improve the potential of ePTFE as a biomaterial, 2-hydroxyethyl methacrylate (HEMA) was grafted onto the ePTFE surface using the gamma irradiation technique. The characteristics of the grafted ePTFE were successfully evaluated using attenuated total reflectance Fourier transform infrared (ATR-FTIR), field-emission scanning electron microscopy (FESEM)/energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). Under the tensile test, the modified ePTFE was found to be more brittle and rigid than the untreated sample. In addition, the grafted ePTFE was less hydrophobic with a higher percentage of water uptake compared to the untreated ePTFE. The protein adsorption test showed that grafted ePTFE could adsorb protein, which was denoted by the presence of N peaks in the XPS analysis. Moreover, the formation of the globular mineral on the grafted ePTFE surface was successfully visualized using the FESEM analysis, with a ratio of 1.94 for Ca:P minerals by the EDX. To summarize, the capability of the modified ePTFE to show protein adsorption and mineralization indicates the improvement of the polymer properties, and it can potentially be used as a biomaterial for implant application.

Comparative durability of GFRP composite reinforcing bars in concrete and in simulated concrete environments

Many studies suggest that the durability of glass-fiber-reinforced-polymer (GFRP) bars in a simulated concrete pore solution is very different than the same bars in an actual concrete environment. This study conducted a comparative evaluation of the durability of GFRP bars in concrete and in simulated concrete environments by investigating their interlaminar shear strength. It focused on evaluating the physical, mechanical, and microstructural properties of GFRP bars subjected to high moisture, saline, and alkaline environments. Bare GFRP bars and cement-embedded GFRP bars were immersed in solutions at different temperatures (23 °C, 60 °C, and 80 °C) and for different exposure times (28, 56, and 112 days). The results show that the percentage water uptake and the apparent diffusivity of the GFRP bars were strongly dependent on the type and temperature of the immersion solution. The interlaminar shear strength of the GFRP bars directly immersed in a solution degraded more significantly than those embedded in concrete and immersed. Moreover, the alkaline solution was more aggressive to the GFRP bars than tap water or saline solution, affecting bar fiber, matrix interface, and chemical structure. As a result of this study, master curves and time-shift factors were developed to correlate the retention of interlaminar shear strength from the accelerated aging test to the service life of GFRP bars in an actual concrete environment.

Effect of clay loading on the water resistance of ternary-filled natural rubber composites

Water immersion was performed on 13 natural rubber (NR) composites filled with varying proportions of carbon black (CB), organically-modified bentonite (M−BNT) and raw bentonite (BNT), to determine the effect of clay loading on the water barrier properties of ternary-filled NR composites. These composites were prepared using a third-degree simplex lattice mixture design of experiment. Specimens were immersed at 80℃ deionized water for 1200 h to measure their percentage water uptake and diffusion coefficient. Results showed that mixing 2.5 phr M−BNT and 2.5 phr BNT to 10 phr of CB provides outstanding water resistance to NR composites. It improved the percentage water uptake by 25.07% and diffusion coefficient by 41.12% as compared to pure CB filler (15/0/0). However, increase in clay loading to pure M−BNT (0/15/0) and pure BNT (0/0/15) led to poor water resistance due to aggregation of fillers. But this observation is less pronounced in M−BNT due to its increased hydrophobicity as a result of organic modification. Contour plots generated from reduced hierarchical models were able to give a graphical representation of the observed results. High values of coefficient of determination with values of 95.40% and 90.15% were computed for percentage water uptake and diffusion coefficient, respectively.

Sawdust Short Fiber Reinforced Epoxidized Natural Rubber: Insight on Its Mechanical, Physical, and Thermal Aspects

In this work, Epoxidized natural rubber/sawdust short fiber (ENR-50/ SD) composites at different fiber content (5, 10, 15 and 20 phr) and size (fine size at 60–100 μm and coarse size at 10–20 mm) were prepared using two-roll mill and electrical-hydraulic hot press machine respectively. Curing characteristics, water uptake, tensile, morphological, physical, and thermal properties of the composites were investigated. Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase. Though the decline of tensile strength and elongation at break values, modulus, hardness and crosslinking density have shown enhancements with the increasing of SD content. The water uptake percentage of all samples has shown an increasing as SD content increase. However, the low SD content, particularly fine size have presented lower water uptake. The temperature of weight% loss (5 and 50 wt% loss) of 5 phr SD (low content) have recorded higher temperature compared to 20 phr SD (high content) in the rubber composites, which indicated higher thermal stability. The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.

Efficiently selective adsorption of Pb(II) with functionalized alginate-based adsorbent in batch/column systems: Mechanism and application simulation

Efficient and selective capture of metal ions from actual wastewater is the global challenge but of utmost significance towards the treatment and recovery of toxic metal wastes. Herein, a novel N/O-enrichment adsorbent (CM0.5AP0.75) with throughout adsorption sites and square-built ions/molecules diffusion pathway, transformed from polyethyleneimine/melamine co-functionalized alginate, was simply obtained utilizing sol-gel technology. Benefiting from the synergy effect of monovacancy nitrogen/oxygen species (high content and strong surface polarity) of adsorbent and discrepant physicochemical property of metal ions, the CM0.5AP0.75 possessed a strong adsorption capacity (596.68 mg/g) towards Pb2+ and a selectivity order of Pb2+ > Cu2+ > La3+ > Cd2+ > Ni2+. Specific focus is placed on highest selectivity of CM0.5AP0.75 for Pb2+ (distribution coefficient (Kd) of 4.6 × 104 mL/g and selective coefficient (k) of 2956.15 in Pb2+/Ni2+ binary system) that could be utilized to verify the efficient selective separation of targeted lead ions in batch/column operating systems. The FT-IR, along with XPS analysis, confirmed that the selective capture of Pb2+ mainly depended on ion-exchange/surface-complexation under the guidance of Hard-Soft-Acid-Base theory. For potential applications, the cooperation of bead-like shape and enhanced strength-toughness (formation of coating skin and incorporation of rigid melamine; max percentage of water uptake = 71.89%) endowed the prepared adsorbent with minimal loss in performance and continuous impact resistance. More convincingly, compared with other works that mostly focused on static adsorption, the work was firstly tied to give a comprehensive evaluation of dynamic adsorption behavior of flowing unitary/binary/quinary metal ions on CM0.5AP0.75 in fixed-bed columns, especially dynamic selective adsorption (continuous adsorption of 7000 min; high column selectivity of Pb2+). The study provides theoretical and practical guidance for the efficient remediation of actual wastewater.

Impact of Salinity Stress on Germination of Water Spinach (Ipomoea aquatica)

Aims: Salinity is one of the major abiotic stress that negatively affects plant growth in germination and early seedling stages. Salinity has becoming a serious problem as most of the parts of worldwide lands were affected by high salt concentration. Therefore, the effects of salinity ranging from 0 mM, 25 mM, 50 mM and 75 mM Sodium chloride (NaCl) concentrations on germination and early seedling growth of water spinach and their salt tolerance mechanism.
 Study Design: Completely Randomized Design (CRD).
 Place and Duration of Study: This study was conducted at Tissue Culture Laboratory, Department of Biology, Faculty of Science in University Putra Malaysia (UPM) from June to August, 2018.
 Methodology: In order to study the effects of salinity on water spinach, several parameters have been taken into account for measurement which include water uptake percentage, germination percentage, germination index, mean germination time, relative injury rate, seed vigor, seedling height reduction, hypocotyl and radicle length, seedling biomass, salt tolerance, total phenolic content and total flavonoids contents.
 Results: The results obtained showed that salinity adversely reduced water uptake efficiency, seed vigor, hypocotyl and radicle length, total phenolic content and total flavonoids content of water spinach. The seedling height reduction of water spinach increased significantly in relative to increasing salinity. However, seeds treated in mild salt concentration at 25 mM of NaCl showed an increment of germination percentage and germination index.
 Conclusion: Salt tolerance of water spinach increased as the response towards increasing salinity.

Controlled Release of Peppermint Oil from Paraffin-Coated Activated Carbon Contained in Sachets to Inhibit Mold Growth During Long Term Storage of Brown Rice.

The aim of the study was to control the release of peppermint oil (700 µL/L) by coating activated carbon (AC) contained in sachets with different solutions (tapioca starch, corn starch, gelatine, carnauba, paraffin, and mixed carnauba-paraffin) for inhibiting the growth of Aspergillus flavus on brown rice (BR). Paraffin-coated AC with adsorbed peppermint oil was then applied to extend the shelf life of BR during long-term storage (60 days) at 30±2°C. The mechanism of peppermint oil vapor release in this system was also studied using GC-MS. The result revealed that paraffin-coated AC with adsorbed peppermint oil present in sachets showed the highest antifungal activity against A. flavus growing on the surface of BR. In addition, paraffin-coated AC with adsorbed peppermint oil could prolong the shelf life of BR from 10 days (control) to at least 60 days under tropical climatic conditions. Moreover, storage of BR in the presence of sachets containing paraffin-coated AC with adsorbed peppermint oil at a concentration of 700 µL/L revealed no significant effects on major rice quality-related factors, such as moisture content, color, water uptake percentage, and gelatinization temperature. Peppermint oil component analysis by GC-MS indicated that paraffin could trap some minor components of peppermint oil and allow the major components such as menthone, menthol, and alpha-pinene, which are compounds that play an important role in mold growth inhibition, to be exposed to air. Thus, this research demonstrated the potential of paraffin-coated AC containing adsorbed peppermint oil for controlling the growth of molds during prolonged rice storage. PRACTICAL APPLICATION: Paraffin-coated activated carbon with adsorbed peppermint oil has the potential to be commercially applied to brown rice grains for facilitating long-term storage. This technique is beneficial for avoiding the occurrence of negative sensorial factors when peppermint oil vapors are used. This process is interesting and easy to apply during large-scale implementation of a rice storage system.

Characteristics of fast-growing wood impregnated with nanoparticles

Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia. However, its wood is low quality with low density, and poor strength, durability, and dimensional stability. This study determined the effects of impregnation with monoethylene glycol (MEG) and nano-SiO2 on the characteristics of sengon wood, including its dimensional stability and density. Impregnation with MEG and nano-SiO2 had a significant effects on dimensional stability in terms of the weight percent gain, anti-swelling efficiency, water uptake, bulking effect, and density. The impregnated wood was examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction. The results show that MEG and nano-SiO2 were distributed homogeneously into cell walls of wood treated with 0.5% MEGSiO2.

Design of transdermal patch of ketoprofen by full factorial design for treatment of rheumatoid arthritis

Oral therapy of NSAIDs for treatment of rheumatoid arthritis causes gastric irritation and ulceration. In the present study transdermal patch of ketoprofen was developed using hydroxyl propyl methyl cellulose E5 and Eudragit S100. Patches were prepared by solvent evaporation method. Optimization was carried out by 32 factorial design with polymer concentration (HPMC E5) and plasticizer concentration (propylene glycol) as independent variables. Patches were evaluated for folding endurance, surface pH, drug content, percent moisture content, water uptake and swelling studies. Ex vivo permeation studies of optimized patch was performed using Franz diffusion cell while bioadhesion force and tensile strength were measured by using texture analyzer. Hydrophilic nature, swelling ability and wettability of polymer and plasticizer were responsible for increase in flux and bioadhesion with increase in their concentrations in the factorial batches. Swelling index of all formulations was in the range of 17.3 ±1.2 to 65.29 ±4.78 up to 3h. Flux obtained from all batches was in the range of 3.37±0.23 to 5.43±0.13µg/h/cm2. Anti-inflammatory studies using carrageenan-induced rat paw edema showed greater paw swelling reduction in case of ketoprofen patch. Cumulative percent drug permeation of optimized patch through nylon 66, Wistar rat skin and cadaver skin was found to be 92.3% >86.28 %>63.42% in 8h, while flux order was 6.073> 5.442 > 2.219 µg/h/cm2 respectively. The study concludes that transdermal patch of ketoprofen will be more efficacious with absence of gastric irritation observed in oral formulations.
 Keywords: Ketoprofen, Bioadhesion, HPMC E5, Flux, Backing membrane

Effects of irrigation and fertilization management on reducing nitrogen losses and increasing corn yield under furrow irrigation

Furrow irrigation is the most widely used method of irrigation in the world. The main objective of this study was to investigate the simultaneous management of water and fertilizer in furrow irrigation on corn yield and nitrogen losses. Large scale field experiments were performed in 16 treatments included 80 furrows with a length of 190 m and longitudinal slope of 0.004. The main factor included planting a row on a ridge of 37.5 cm (So) and two rows on a ridge of 75 cm (SR2), and the sub-factor included two irrigation management and 4 fertilization strategies included 3 fertilizer placement on the furrow and ridge (P1, P2 and P3) and fertigation (F). The results showed in all fertilization nitrate losses in So treatment was more than SR2 treatment. The highest nitrate losses occurred in P1 (fertilizer placement on the furrow bottom) and the lowest in P3 (fertilizer placement on the ridge) fertilization. Optimal irrigation applied increased application efficiency, root water and nitrate uptake and reduced nitrate losses up to 50% in So (P1 fertilization) and 22% in SR2 treatment (P2 fertilization) compared to conventional irrigation. Due to the higher percentage of root water and nitrate uptake in So treatment than SR2 in similar fertilizer treatments, plant height, stem diameter, ear weight and number of seeds on the cob of ear in So treatment were higher than SR2, but the grain yield was more in SR2 treatment due to plant densities. The highest grain yield and water productivity in SR2-OI-P3 treatment (wide ridge- optimal irrigation- ridge fertilization), increased by 44.2% and 67.4%, respectively. This study showed that the simultaneous management of water and fertilizer had a significant effect on the increase of water productivity and yield.

FORMULATION AND OPTIMIZATION OF FLOATING TABLETS OF CLOPIDOGREL BISULPHATE USING DESIGN OF EXPERIMENTS

Objective: The present study aimed at designing of floating matrix tablet of clopidogrel bisulphate by design of experiments.Methods: The tablets were prepared by direct compression technique using hydroxypropyl methylcellulose K15 (HPMC) as a matrix polymer and sodium bicarbonate as a gas generating agent. In order to optimize the concentration of HPMC (X1) and sodium bicarbonate (X2), a 32 full factorial design was employed. The tablet formulations were evaluated for floating lag time (Y1), floating or buoyancy time (Y2), percent water uptake, and differential scanning calorimetry (DSC) and in vitro drug release (Y3).Results: The formulation variables, HPMC concentration, and sodium bicarbonate concentration exerted a significant effect on floating behavior and drug release characteristics of the tablet. The optimized formulation, with 15% sodium bicarbonate concentration and 30 % HPMC concentration resulted in 5±2.6 sec of floating lag time, 22.0±0.6 h of floating time and 42.0±0.99% of clopidogrel bisulphate release in 8 h of dissolution study. The drug release mechanism was identified as nonfickian. The water uptake studies revealed that with an increase in HPMC concentration, there was an increase in swelling index of tablet whereas higher sodium bicarbonate concentration supported the faster erosion of matrix tablets. DSC study revealed no interaction of drug and polymers. The lower percentage error between predicted and observed responses of the optimized formulation validated the design.Conclusion: The study demonstrated successful designing of floating clopidogrel bisulphate tablet with factorial design.