165 research outputs found

    A Review on The Cooling Technique of Solar PV System

    Get PDF
    Being the most widespread renewable energy generation system, photovoltaic (PV) systems face major problems, overheating and low overall conversion efficiency. The electrical efficiency of PV systems is adversely affected by significant increases in cell temperature upon exposure to solar irradiation.  There have been several ways to remove excess heat and cool down the PV to maintain efficiency at fair levels. A hybrid photovoltaic/thermal system cooled by forced air circulation blown by a PV-powered fan can set up, and a rectangular control volume with cylindrical ends has been built at the back of the PV panel where aluminum fins have been placed in different arrangements and numbers

    Study of Computational and Experimental Methodologies for Cracks Recognition of Vibrating Systems using Modal Parameters

    Get PDF
    Mostly the structural members and machine elements are subjected to progressive static and dynamic loading and that may cause initiation of defects in the form of crack. The cause of damage may be due to the normal operation, accidents or severe natural calamities such as earthquake or storm. That may lead to catastrophic failure or collapse of the structures. Thereby the importance of identification of damage in the structures is not only for leading safe operation but also to prevent the loss of economy and lives. The condition monitoring of the engineering systems is attracted by the researchers and scientists very much to invent the automated fault diagnosis mechanism using the change in vibration response before and after damage. The structural steel is widely used in various engineering systems such as bridges, railway coaches, ships, automobiles, etc. The glass fiber reinforced epoxy layered composite material has become popular for constructing the various engineering structures due to its valuable characteristics such as higher stiffness and strength to weight ratio, better damage tolerance capacity and wear resistance. Therefore, layered composite and structural steel have been taken into account in the current study. The theoretical analysis has been performed to measure the vibration signatures (Natural Frequencies and Mode Shapes) of multiple cracked composite and structural steel. The presence of the crack in structures generates an additional flexibility. That is evaluated by strain energy release rate given by linear fracture mechanics. The additional flexibility alters the dynamic signatures of cracked beam. The local stiffness matrix has been calculated by the inverse of local dimensionless compliance matrix. The finite element analysis has been carried out to measure the vibration signatures of cracked cantilever beam using commercially available finite element software package ANSYS. It is observed from the current analysis, the various factors such as the orientation of cracks, number and position of the cracks affect the performance and effectiveness of damage detection techniques. The various automated artificial intelligent (AI) techniques such as fuzzy controller, neural network and hybrid AI techniques based multiple faults diagnosis systems are developed using vibration response of cracked cantilever beams. The experiments have been conducted to verify the performance and accuracy of proposed methods. A good agreement is observed between the results

    Design, synthesis and biological activities of 5Hdibenzo[ b,f]azepine-5-carboxamide derivatives; Targeted hippocampal trypsin inhibition as a novel approach to treat epileptogenesis

    Get PDF
    Purpose: To synthesize anticonvulsant drug derivatives that target protease-activated receptor generated epileptic seizures.Method: Varieties of carbamazepine-based Schiff bases were designed with different aldehydes and ketones, and evaluated for in silico computer-aided drug design prediction of absorption, distribution, metabolism and excretion (ADME), and potential drug targets. The resultant compounds were synthesized and characterized by various spectroscopic techniques, including FTIR, 1H-NMR and 13CNMR, analysis. Thereafter, they were screened for antimicrobial, antioxidant and anticonvulsant potential.Results: Prominent anti-protease potential was shown by C7 and C3 compounds and the order of activity was C7 > C3 > C5 > C2 > C6 > C4 > C2 > C1 (p < 0.05). The anticonvulsant activity of C7 and C5 was comparable with the standard drug; C3, C4, C6 and C8 had mild activity while C1 and C4 showed the least activity. The synthesized compounds exhibited significant (p < 0.05) antioxidant potential (rank order: C3 > C4 > C5 > C7 > C8 > C6 > C1 > C2) and antimicrobial activity against S.aureus and B. bronchiseptica (rank order: C5 > C2 > C8 > C1 > C4 > C3 > C7).Conclusion: Synthesized derivatives retained their potential for anticonvulsant and antitrypsin activity, unlike their mother moiety, i.e., carbamazepine. The additional antibacterial activity effectively treats neurological disorders associated with bacterial infections

    BEHAVIOUR OF SILTY SAND REINFORCED WITH LOW DENSITY POLYETHYLENE (LDPE) STRIPS

    Get PDF
    In this study, silty sand is reinforced with plastic strips to improve the engineering properties of soil. Sand and silty sand soils have been used as base materials and low-density polyethylene (LDPE) strips as reinforcement materials. The LDPE strips are used in various dimensions (e.g., width ranging from 6 to 15mm and length ranging from 15 to 30mm). The randomly distributed LDPE strips are added to sand and silty sand specimens at varying percentages (e.g., 0.1% to 0.3%) by weight of dry soil specimen. Direct shear tests are performed on sand and silty sand specimens in both unreinforced and reinforced conditions. Stress strain, volumetric strain (e.g., compression/dilation behaviour) and strength envelopes are plotted to investigate the improvement in the shear strength parameter (e.g., internal friction angle). The results show that in sand specimens, the maximum improvement in shearing behaviour has been achieved with strips of 6x30mm in dimensions and at 0.3%. For silty sand specimens, the maximum improvement in shearing behaviour has been achieved with strips of 6x25mm in dimensions and at 0.3%. In addition, it has been observed that reinforced soil specimens increased the values of internal frictional angle compared to unreinforced soil specimens. In sand specimens, maximum increase of 19.72% in internal friction angle (Φ) has been observed with 6x30mm strips at similar percentage. In case of silty sand specimens, the maximum increase in internal friction angle (Φ) has been observed as 19.28% with the addition of strips of 6x25mm and at 0.3%

    Growth Response of Buffel Grass (Cenchrus ciliaris) to Phosphorus and Mycorrhizal Inoculation

    Get PDF
    Arbuscular-mycorrhizal symbiosis confers numerous benefits to host plants including improved tolerance to abiotic and biotic stresses. Although the majority of grasses form an arbuscular mycorrhizal symbiosis, little is known of the mycorrhization of Buffel grass (Cenchrus ciliaris). A pot study was conducted in sterilized soil to determine the effect of mycorrhizal inoculation and phosphorus amendment on the biomass production in C. ciliaris. Mycorrhizal fungi used were Gigaspora rosea, Glomus intraradices and Glomus etunicatum. Inoculation with Gigaspora rosea alone, and combined incoculation with Glomus intraradices + Gigaspora rosea and Glomus intraradices + Glomus etunicatum signifi cantly (P<0.05) increased dry biomass in unamended and 25 kg P2O5 ha-1 treatments. Combined inoculation with Glomus intraradices + Gigaspora rosea and Glomus intraradices + Glomus etunicatum showed pronounced (P<0.05) eff ect on dry biomass compared to inoculation with Gigaspora rosea alone in unamended and 25 kg P2O5 ha-1 treatments. Combined inoculation with Glomus intraradices + Glomus etunicatum resulted in signifi cantly (P<0.05) higher dry biomass campared to the combined inoculation with Glomus intraradices + Gigaspora rosea and inoculation with Gigaspora rosea alone in unamended and 25 kg P2O5 ha-1 treatments. Th e results clearly show that inoculation of C. ciliaris plants with mycorrhizal fungi Gigaspora rosea, Glomus intraradices and Glomus etunicatum is highly benefi cial for the growth and biomass production in the absence or presence of P2O5 under sterile soil conditions. Inoculation of C. ciliaris plants with these mycorrizal fungi may help in forage production in marginal and shallow soils of the rangelands of Pakistan

    Synthesis and characterization of some new Schiff base derivatives of gabapentin, and assessment of their antibacterial, antioxidant and anticonvulsant activities

    Get PDF
    Purpose: To synthesize and characterize some new gabapentin Schiff base derivatives, and to assess their antibacterial, antioxidant and antiepileptic activities.Methods: Four Schiff base derivatives of gabapentin, termed G1, G2, G3 and G4, were synthesized by condensation with benzoin, vanillin, acetophenone, and benzophenone, respectively. Their chemical identities were established by FTIR, 1 H NMR and 13C NMR techniques. The new compounds were screened for antibacterial activity using agar well method, antioxidant activity by DPPH assay, and anticonvulsant activity against pentylenetetrazole (PTZ) induced seizures in mice.Results: All the compounds showed antibacterial activity against the test strains to variable degrees, while the parent drug did not exhibit antibacterial activity. The zones of inhibition of compound G2 against Micrococcus luteus (36.2 ± 1.0 mm) and Serratia marcescens (28.2 ± 1.0 mm), and of compound G4 against Stenotrophomonas maltophilia (36.8 ± 1.0 mm) were larger compared to thestandard drug, doxycycline, exhibiting zones of inhibition 28.2 ± 1.3, 28.2 ± 0.9 and 20.0 ± 0.9 mm, respectively. In addition, compounds G1 and G2 possessed significantly greater (p &lt; 0.05) radical scavenging activity (82.3 ± 1.8 and 92.3 ± 2.2 %, respectively) than the precursor drug, gabapentin (63.2± 2.6 %). The seizure scores for compounds G1 (0.7 ± 0.06) and G2 (0.9 ± 0.07) were comparable(p ˃ 0.05) with gabapentin (0.8 ± 0.06), while compounds G3 and G4 were less active (p &lt; 0.05) than gabapentin.Conclusion: Compounds G1 and G2 exhibit good antibacterial and antioxidant activities while retaining the anticonvulsant activity of the parent drug, gabapentin, thus making them suitable candidates for further development for the treatment of neurodegenerative pathologies associated with bacterial infections. Keywords: Gabapentin, Antibacterial, Seizures, Antioxidant, Anticonvulsan

    Antifungal and antispasmodic activities of the extracts of Euphorbia granulata

    Get PDF
    The dichloromethane and methanolic extracts of the plant Euphorbia granulata were investigated for their antifungal, antibacterial, phytotoxic, brine-shrimp cytotoxic, antioxidant, spasmolytic (antispasmodic) and acetylcholinestrase inhibitory activities. The dichloromethane extract showed strong inhibition against Microsporum canis (90%) and against Aspergillus flavus (50%). Both the extracts inhibited the spontaneous contractions in rabbit jejunum preparations with EC50 value of 0.17 and 1.3 mg/mL, respectively and also relaxed the K+-induced contractions with EC50 0.2 and 2.8 mg/mL, respectively, suggesting a calcium channel blocking activity. However, the extracts did not show antibacterial, phytotoxic, brine-shrimp cytotoxic, antioxidant and acetylcholinestrase inhibitory activities

    Hexagonal Printed Monopole Antenna with Triple Stop Bands for UWB Application

    Get PDF
    Inherently UWB (Ultra Wideband) communication systems comes with interference problem with some if the existing narrowband communication systems. These bands are stopped with the help of band-stop filter in order to reduce electromagnetic interference However, the complexity and limitations are increased due to these filters, hence this solution is turned down in those applications where design complications and complexity is of concern. Introducing various slots of specific shapes and exact dimensions however, have solved this issue for the researchers around the world. This paper presents a hexagonal PMA (Printed Monopole Antenna) with triple stop bands. The antenna is used for UWB application. The antenna is stopped the WiMAX (Worldwide Interoperability for Microwave Access), WLAN (Wireless Local Area Network) and ITU (International Telecommunication Union) bands. The antenna dimensions are 30x28x16 mm3. FR4 is used between ground and radiating patch with relative permittivity of 4.4. The VSWR (Voltage Standing Wave Ratio) is less than 2 between 3-11 GHz except WiMAX (3.1-3.7 GHz), WLAN (5.1-5.8 GHz) and the ITU frequency band (7.95-8.4 GHz). The antenna is design in CST software

    Effects of probiotic on the intestinal morphology with special reference to the growth of broilers.

    Get PDF
    The probiotic (Protexin)® increases the growth rate in broilers. It must interfere with the intestinal cell morphology and absorption. The intestinal epithelium is one of the most rapidly renewed tissues in the body and is renewed by a process of continuous cell division. This study was carried out with an aim to establish a link between the use of probiotic doses, growth rate, and intestinal cell proliferation by measuring the length and weight of the intestine and intestinal crypt cell proliferation (CCP) of broiler chicks. The results revealed significant increase in intestinal CCP but no effect was observed on the intestinal weight and length. The increase in CCP has also no significant influence towards growth factor. The increased weight gain in this study is associated with more feed consumption which is observed with Protexin® dose 1.0 g / 10 kg of feed. Furthermore, feed consumption reduced beyond this dose may lead to reduced weight gain

    Genetic transformation of sugarcane variety HSF-240 with marker gene GUS

    Get PDF
    In the current research an efficient transformation system for sugarcane was established. Shoot tip of variety HSF-240, excised from a six months old field grown plants were used as explant. For transformation, Agrobacterium tumefaciens strain EHA101 with vector pIG121 Hm, harboring GUS, HPTII and NPTII genes were used. HPTII is a hygromycin resistant while NPTII is a kanamycin resistant gene. Effects of Acetosyringone, duration of co-cultivation and pre-selection, concentration of cefotaxime and hygromycin in medium on transformation efficiency were studied. High transformation efficiency and 60% GUS expression was observed when 50 μM acetosyringone was added in the co-cultivation medium. Among different durations of co-cultivation, 48 h produced high (40%) transient GUS positives with an absolute control of bacterial growth. For pre-selection, seven days gave a high transformation efficiency of 10%. Cefotaxime concentration of 1000 mg/L proved optimal for pre-selection of the explants with efficient control of bacterial growth. A high regeneration (31%; P < 0.01) of the transformants was observed at 50 mg/L hygromycin. Presence of GUS gene was confirmed by PCR analysis and only the transgenic plants contained the 430 bp fragment of GUS gene. The new protocol developed in this study could be used for the efficient transformation of sugarcane with desired gene to produce insect/pest resistant, drought tolerant and high yielding sugarcane varieties in future
    corecore