209 research outputs found
Effect of NaOH Treatment on Properties of Phoenix Sp. Fiber
No full textThe aim of this paper is to investigate the effect of an alkali treatment on physical, chemical, mechanical, and morphological properties of Phoenix Sp. fibers. The use of natural fibers as reinforcement in polymer composites requires a deep investigation to understand their behavior and which treatment is more appropriate to improve the quality of the untreated material. For this reason, fibers were extracted from the petioles of the Phoenix Sp. plant and they were treated with NaOH solution in different weight concentrations (5%, 10%, and 15%). The mechanical behavior was investigated through tensile test on single fiber at different gauge length (20 mm, 30 mm, 40 mm, 50 mm, and 60 mm). Chemical and physical analysis were performed to define the material properties. In particular, density analysis of untreated and treated fibers, optical analysis to measure the diameter of the fibers, moisture content evaluation, and a chemical composition analysis were carried out through standard methods. The modification of the surface morphology due to the alkali treatment was analyzed through scanning electron microscope analysis
Synergistic effect of fiber content and length on mechanical and water absorption behaviors of Phoenix sp. fiber-reinforced epoxy composites
No full textPhoenix sp. fiber-reinforced epoxy composites have been manufactured using compression molding technique. The effect of reinforcement volume content (0%, 10%, 20%, 30%, 40%, and 50%) and size (300 Âμm particles, 10 mm, 20 mm, and 30 mm fibers) on quasi-static and dynamic mechanical properties was investigated. Moreover, the water absorption properties of composites were analyzed at different environmental conditions (10â, 30â, and 60â). For each reinforcement size, composites loaded with 40% in volume show highest tensile and flexural properties. Furthermore, composites with 300 Âμm particles present the best impact properties and the lowest water absorption, regardless of the environmental condition. The dynamic mechanical properties of the composites loaded with 40% in volume were analyzed by varying the reinforcement size and the load frequency (i.e., 0.5 Hz, 1 Hz, 2 Hz, 5 Hz, and 10 Hz). It was found that the glass transition temperature of short fiber-reinforced composites is higher than that of the composite loaded with particles
Effect of indigenous arbuscular mycorrhizal fungi on some growth parameters and phytochemical constituents of Pogostemon patchouli Pellet
No full textPatchouli (Pogostemon patchouli Pellet) is an important aromatic crop cultivated for its essential oil used in cosmetics. arbuscular mycorrhizal (AM) fungi is known to modify several aspects of plant physiology and phytochemical constituents. Hence, a study was conducted on the efficacy of certain AM fungi in the improvement of some growth parameters and content of some phytochemical constituents in the leaves of P. patchouli. Patchouli seedlings were raised in soil inoculated with isolates of seven indigenous AM fungi, viz. Acaulospora scrobiculata, Gigaspora margarita, Glomus aggregatum, G. geosporum, G. mosseae, Sclerocystis pakistanika and Scutellospora heterogama. Seedlings raised in the presence of AM fungi generally showed an increase in growth, nutritional ingredients (sugars, N, P, K, Zn, Ca and Mn), total chlorophyll, and secondary metabolites in the leaves of patchouli compared to those from seedlings grown in the absence of AM fungi, the extent of increase, however, being varied with the AM fungi species. Furthermore, it was found that the phosphorus concentration was positively correlated with all growth parameters and content of phytochemical constituents (except essential oil), and that G. aggregatum seemed to be the best AM symbiont for the patchouli plant used in this experiment
Sustainable recycling technologies for thermoplastic polymers and their composites: A review of the state of the art
No full textThis review article discusses the environmental and economic effects of recycling, as well as sustainable thermoplastic polymer recycling technologies. Several researchers have utilized recycled thermoplastics as matrices in the production of a variety of natural and synthetic-based composites, which is also the focus of this study. All of the industries (food and packaging, construction and building, transportation, and indoor usage) where recycled thermoplastics have a large market share (food and packaging, construction and building, transportation, and indoor usage) are covered in this review. The desirable properties of thermoplastic polymers, such as corrosion resistance, low density, and user-friendliness, have caused plastic production to surpass aluminum and other metals in use over the past 60 years. Furthermore, recycling is one of the most important measures available to mitigate these effects and is one of the most dynamic segments of the plastics industry at present. Increased landfilling and incineration of plastics have a negative impact on the ecosystem, and the continued increase in the production of virgin fossil plastic also has a negative impact on the environment. Consequently, this continuous production could lead to the depletion of fossil fuel resources, an increase in environmental emissions during processing, and eventual incineration. Increasing numbers of nations are adopting the circular economy concept in an effort to avoid all of these problems. This concept emphasizes the reuse of products and resources, as well as the recycling of materials according to the waste hierarchy, rather than their cremation or disposal in the environment
An Investigation of the use of Solaria as a source of Heat for House in New Zealand
No full textFull text is available to authenticated members of The University of Auckland only.A solarium is normally viewed as an arcane method of capturing solar radiation to warm houses since the cost of heating them at night is likely to exceed the energy gains during the day. However with modern “smart building technologies” it may be possible to control the parameters of the building so that day time solar gains can be stored and nighttime losses minimized. In general application solaria are most effective at very low level of incident solar radiation whereas mass wall and Trombe wall systems are more efficient at higher level of incident solar radiation. However the heating problems of NZ buildings are important only in the cooler lower incident radiation part of the year. We are experimenting with a thermosyphon passive solar hot water collector system mounted on a north facing part of the solarium which could minimise summer overheating of the Solarium and provide hot water throughout the year to household. Excessive solar heat gain in summer is intended to be captured in insulated water storage tanks. Blinds/movable insulation is deployed to prevent excessive heat loss through the solarium’s glazing at night. This model requires meteorological data to approximate the sizing of the system for the building requirement and is sensitive to meteorological parameters such as solar radiation, temperature and wind. A numerical calculation corresponding to the thermal analysis of the building and meteorological data yields the scale and nature of the system that would perhaps give adequate living conditions all year or, if smaller, for a large part of the year
Correlation of gastro esophageal valve, symptomatology and 24 hour pH monitoring in GERD patients with refractory symptoms in South India - A Cross Sectional study.
No full textINTRODUCTION :
Gastro Esophageal Reflux Disease (GERD) is a most commonly encountered
problem in day today practice. It result from failure of the anti reflux barrier
which expose esophageal mucosa to abnormal acid reflux / GER (Gastro
Esophageal Reflux) which in turn results variety of symptoms such as heartburn,
odynophagia, hoarseness of voice, Increased mucus in the throat, foreign body
sensation of throat or globus, water brash, and many atypical symptoms such as
chronic cough, recurrent sore throat and asthma if long standing.
Behind liver disease, it was considered the costlier GI disease with ranking
second in 2004 with the prevalence rate in general population varies between
42% to 45% and 24% of the population will experience heartburn daily or more
often.
In spite of effective treatment, around 20–40% of patients showed partial or lack
of response to medical therapy that are labeled as refractory GERD and these set
of patient are difficult to treat.
It is caused by a failure of the anti reflux barrier (ARB). Gastro esophageal valve
(GEV) is one of the components of it. Alteration of this valve which in turn
alters of lower esophageal sphincter length and pressure which results
mechanically defective sphincter.
Esophageal acid exposure is directly proportional to the degree of gastro
esophageal valve geometry. Reinforcement of the GEV by means of endoscopic
methods or surgery may improve the symptoms in these patients with refractory
symptoms.
Our present study was design to identify the type of gastro esophageal valve in
GERD patients with refractory symptoms and correlation of symptoms and 24
hour pH monitoring findings.
AIM OF THE STUDY : This study was conducted to identify the grades of gastro
esophageal valve (GEV) in gastro esophageal reflux disease (GERD) patients
with refractory symptoms and to correlate the grades of GEV with 24 hour pH
monitoring findings.
METHODS : 30 patients with symptoms of GERD inspite of proton pump
inhibitor therapy (omeprazole 20mg, twice daily) for 4 weeks were studied in
Rajiv Gandhi general hospital, madras medical college, Chennai-3
RESULTS : This study revealed higher grade of gastro esophageal valve(grade 3
& grade 4) had abnormal acid reflux evidenced by 24 hour pH monitoring
(percent of time pH < 4, Demeester score) than grade 1 & grade 2 GEV.
Patients with grade 3& grade 4 GEV had more incidences of distal esophagitis
than grade 1 & grade 2.
CONCLUSION : Presence of abnormal gastro esophageal valves which are
detected by retro flexion of upper GI endoscopy may predict the positive
esophageal acid exposure and complication such as erosive esophagitis
Variability in growth, nutrition and phytochemical constituents of Plectranthus amboinicus (Lour) Spreng. as influenced by indigenous arbuscular mycorrhizal fungi
No full textA study was conducted under greenhouse nursery condition on the efficacy of seven indigenous arbuscular mycorrhizal (AM) fungi in the improvement of growth, biomass, nutrition and phytochemical constituents, namely total phenols, ortho dihydroxy phenols, flavonoids, alkaloids, tannins and saponins, in the roots and leaves of Plectranthus amboinicus (Lour) Spreng. Seedlings were raised in polythene bags containing soil inoculated with isolates of seven different indigenous AM fungi, viz. Acaulospora bireticulata, A. scrobiculata, Gigaspora margarita, Glomus aggregatum, G. mosseae, G. geosporum, and Scutellospora heterogama. P. amboinicus seedlings raised in the presence of AM fungi generally showed an increase in plant growth, nutritional status and phytochemical constituents over those grown in the absence of AM fungi. The extent of growth, biomass, nutritional status and phytochemical constituents enhanced by AM fungi varied with the species of AM fungi inhabiting the roots and leaves of P. amboinicus seedlings. Considering the various plant growth parameters, nutritional status of the plant, total phenols, ortho dihydroxy phenols, alkaloids , flavonoids , tannins, and saponins in the roots and leaves, it was observed that Gigaspora margarita is the best AM symbiont for P. amboinicus used in this experiment
A New Study on Tribological Performance of Phoenix Sp. Fiber-Reinforced Epoxy Composites
No full textThis paper presents the tribological performance of Phoenix sp. fiber-reinforced tribo-composites based on epoxy. The Phoenix sp. fiber-reinforced epoxy composites were fabricated by varying the fiber length (10, 20, and 30 mm) and fiber volume fraction (10%, 20%, 30%, 40%, and 50%) using the compression molding technique. The dry sliding wear test was conducted using pin-on-disk wear testing machine at different loads (10, 20, and 30 N), sliding speed (1, 2, and 3 m/s), and sliding distance (1, 2, and 3 km). The outcomes revealed that the presence of Phoenix sp. fibers in the composites improved the tribological performance of the neat epoxy. Moreover, the optimal fiber length and the fiber volume fraction were found to be 20 mm and 40%, respectively. The morphology of the worn surfaces of the samples was examined using a scanning electron microscope to study the wear mechanisms
Characterization of Surface Modified Phoenix sp. Fibers for Composite Reinforcement
No full textThis paper reports the morphological, physical, chemical, mechanical and thermal properties of untreated and various chemically treated natural fibers extracted from the petioles of the Phoenix sp. plants. The outcome of morphological analysis revealed that the treated Phoenix sp. fibers have tiny protrusions on its surface which promotes the mechanical interlocking between fiber and matrix. The physical and chemical analysis ensured that the chemical treatments had a positive impact. The chemical functional groups present in the Phoenix sp. fibers were confirmed through FTIR analysis. The improvement in crystallinity index values of treated fibers was confirmed through X-ray diffraction analysis. The fiber treated with acrylic acid exhibited the highest tensile strength and tensile modulus of 466.35 MPa and 9.26 GPa, respectively. The thermal stability of the Phoenix sp. fiber was examined through thermogravimetric analysis and it revealed that the treated fibers have better thermal stability. The above results concluded that the Phoenix sp. fiber is an appropriate reinforcement material for preparing polymer matrix composites
Fuzzy Detour Convexity and Fuzzy Detour Covering in Fuzzy Graphs
No full textA path P connecting a pair of vertices in a connected fuzzy graph is called a fuzzy detour, if its μ - length is maximum among all the feasible paths between them. In this paper we establish the notion of fuzzy detour convex sets, fuzzy detour covering, fuzzy detour basis, fuzzy detour number, fuzzy detour blocks and investigate some of their properties. It has been proved that, for a complete fuzzy graph G, the set of any pair of vertices in G is a fuzzy detour covering. A necessary and sufficient condition for a complete fuzzy graph to become a fuzzy detour block is also established. It has been proved that for a fuzzy tree there exists a nested chain of sets, where each set is a fuzzy detour convex. Application of fuzzy detour covering and fuzzy detour basis is also presented.  
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