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An experimental investigation to compare the flexural strength of a novel betel leaf fiber/cassia auriculata filler reinforced epoxy composite and betel leaf fiber reinforced epoxy composite
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The nanocomposite consists of an iron matrix with fly ash nanopowder and carbon nanotube (CNT) reinforcement through the sintering process. Parameter optimization for enhancing hardness and compressive strength. There were six factors considered such as volume percentage of fly ash (2.5% and 5%) and CNT (2.5% and 5%), size of the CNT (50 nm and 100 nm), sintering temperature (800 °C, 900 °C, and 1000 °C), pressure (500 MPa, 600 MPa, and 700 MPa) and time (15 min, 30 min, and 45 min). Taguchi technique with L36 orthogonal array considered for factors optimization with the superior consequence is convincible condition. The optimized factors for maximum hardness as well as the compressive strength were as follows: fly ash 2.5 vol% and 50 nm size CNT of 5 vol%. The composite samples were produced employing the sintering process. The optimal parameters are the temperature of 1000 °C, sintering pressure of 600 MPa and 15 min. The mathematical model was developed for predicting the hardness and compressive strength for any combinations of factors. The R² value greater than 95% meant that the predicted models have good agreement with the experimented results and were accurate.
Hand lay-up method is frequently used by small companies. It is due to its flexibility and low-cost considerations. One of the qualities problems that normally arises is the product unevenness. This study was carried out to analyse this variation on manufacturing E-glass/epoxy plates specimen and propeller product. Void and fibre volume fraction of manufactured plates are measured based on ASTM-D2734. Propellers of LSU-03 aircraft were manufactured and analysed to find out the uniformity of the product in terms of its mass and size. To determine product compatibility with the design, the geometry and the thickness were measured at several points of propeller. In addition to this, a balancing process is carried out to find out the mass balance point.
Background: The COVID-19 pandemic is found to affect the mental health of the population. Undergraduate medical students are especially prone to mental health disorders and hence could be more vulnerable to the impact of the pandemic. Methods: A prospective longitudinal study was conducted on 217 undergraduate medical students in a medical college at Chennai, India. Depression, anxiety,
and stress levels were recorded using Depression Anxiety Stress Scale 21 Items (DASS21) before and during the COVID-19 outbreak in India in December 2019 and June 2020, respectively. In the follow-up survey, in addition to DASS21, the Pittsburgh Sleep Quality Index to assess sleep quality and a self-administered questionnaire to assess the impact of COVID-19 related stressors were used. The selfadministered
questionnaire assessed the status of COVID-19 testing, interactions
with COVID-19 patients, self-perceived levels of concerns and worries related to academics (COVID-19-AA (academic apprehensions)) and those pertaining to the self and family/friends (COVID-19-GA (general apprehensions)). Cross-sectional and longitudinal comparison of overall scores of depression, anxiety, and stress and scores stratified by gender, year of study, place of residence and monthly family
income were performed. Predictors for depression, anxiety, and stress during COVID-19 were investigated using adjusted binary logistic regression analysis and results were expressed as adjusted odds ratio with 95% confidence interval (CI). A P value < 0.05 was considered statistically significant. Results: The average scores of depression, anxiety, and stress during the baseline survey were 7.55 ± 7.86, 4.6 ± 6.19 and 7.31 ± 7.34 with the prevalence (95% Cl) of 33.2% [27–39.9%], 21.2% [16–27.2%] and 20.7% [15.5–26.7%]; in follow-up
survey, the mean scores were 8.16 ± 8.9, 6.11 ± 7.13 and 9.31 ± 8.18 with the prevalence being 35.5% [29.1–42.2%], 33.2% [27–39.9%] and 24.9% [19.3–31.2%] for depression, anxiety, and stress respectively. There was a significant increase in both the prevalence and levels of anxiety and stress (P < 0.001), with depression remaining unchanged during COVID-19, irrespective of gender, year of study, place of residence and family’s monthly income. Poor sleep quality, higher levels of baseline depression, anxiety, and stress, higher COVID-19-GA, COVID-19 patients in family/friends and direct interactions with COVID-19 patients were found to be significant predictors of negative mental health in undergraduate medical students. COVID-19-AA was not significantly associated with depression, anxiety, and stress. Conclusion: The COVID-19 pandemic appears to negatively affect the mental health of the undergraduate medical students with the prevalence and levels of anxiety and stress being increased, and depression symptoms remaining unaltered. Addressing and mitigating the negative effect of COVID-19 on the mental health of this population is crucial.
Phytosterols are bioactive compounds that are naturally present in plant cell membranes with chemical structure similar to the mammalian cell- derived cholesterol. They are highly present in lipid-rich plant foods such as nuts, seed, legumes and olive oil. Among various phytosterols, β-sitosterol (SIT) is the major compound, found plentiful in plants. It has been evidenced in many in-vitro and in-vivo studies that SIT possesses various biological actions such as anxiolytic & sedative effects, analgesic, immunomodulatory, antimicrobial, anticancer, anti – inflammatory, lipid lowering effect, hepatoprotective, protective effect against NAFLD and respiratory diseases, wound healing effect, antioxidant and anti-diabetic activities. In this review, in order to compile the sources, characterization, biosynthesis, pharmacokinetics, antioxidant and anti-diabetic activities of SIT, classical and online-literature were studied which includes the electronic search (Sci Finder, Pubmed, Google Scholar, Scopus, and Web of Science etc) and books on photochemistry. The experimental studies on SIT gives a clear evidence that the potential phytosterol can be used as supplements to fight against life threatening diseases. High potential of this compound, classifies it as the notable drug of the future. Therefore, immense researches regarding its action at molecular level on life threatening diseases in humans are highly endorsed.
An exaggerated immune response induced in the lower respiratory tract against coronaviruses (CoV’s) including CoViD-19 (2019-nCoV) appears to contribute to the overwhelming lung damage in comparison to the direct viral invasion and replication in the host. While it has resulted in high global rates of morbidity (3,672,238 infected cases), a sizeable number of individuals have already succumbed (254,045 deaths) (1) (case fatality rate of 1-10% ) to severe pathological manifestations involving the lower respiratory tract (2) as of May 7, 2020) as reported by the World Health Organization (1), although this has been documented to be of less severity as compared to influenza (3).
CoViD-19 reportedly has four stages; a pre-symptomatic phase of fever, cough and generalised malaise heralded by high viral loads in severely affected cases. After about a week, the second stage manifests with viral pneumonia that involves the lower respiratory tract (when viral loads in the upper respiratory tract decreases exponentially). A vast majority of patients show clinical improvement as protective humoral responses are developed at this stage of the disease. A minor proportion of individuals progress to the third phase of CoViD-19 by developing symptoms of hypercytokinemia (cytokine release syndrome (CRS)/cytokine storm) characterized by exaggerated levels of pro-inflammatory cytokines and other pathognomonic biomarkers of inflammation leading to rapid onset of acute respiratory distress syndrome (ARDS) and multi-organ failure (Stage 4). It is also intriguing to know that many individuals with CoViD-19 have refrained from developing ARDS. The median time from development of symptomatic disease to death from CoViD-19 is ~2-8 weeks (4). The crown-shaped peplomers of SARS-CoV-2 appear to trigger a prolonged phase of hypercytokinemia that encompasses a broad array of pro-inflammatory mediators like IL-6, IL-1β, TNF-α, CXCL8 (IL-8) together with the infiltration of inflammatory and degranulating cells into the lungs, usually 7-10 days following the onset of symptoms during the second stage of CoViD-19 (4). Variations in human genetic make-up have been shown to affect disease progression and prognosis of infectious diseases. A more recent emergence of interest surrounds individuals harboring mutations in the Mediterranean fever gene (mefv), which likely could predispose the onset of severe CoViD-19 disease manifestations resulting from cytokine storm (5).
Cytokine storm refers to a systemic acute inflammatory manifestation triggered during viral infections characterized by an upsurge in immune cells and cytokine levels (6). It occurs when leukocytes become activated leading to abrupt release of TNF-α, IL-6, IL-1β, IL-10, which at times can be life-threatening due to acute onset of hypotensive shock, and multi-organ failure (6) as reported in CoViD-19 (1, 4). Cytokine storm likely could dampen innate and adaptive immune responses against SARS-CoV-2 infection. Cytokine storm pathophysiology in CoViD-19 is often reported to be due to high levels of IL-6 in individuals (6) although this could synergize with TNF-α and IL-1β levels. A similar kind of hyperactive inflammatory response also appears to have occurred in SARS-CoV and MERS-CoV infections culminating in severe lung fibrosis, often with poor disease prognosis (7). Recent reports suggest that CoViD-19 disease is characterized by exaggerated release of acute phase reactants that includes C-reactive protein (CRP), serum amyloid A, and ferritin, suggesting a rapid activation of the innate immune response (8, 9). Individuals with CoViD-19 reportedly possess elevated levels of circulating TNF-α, IL-1β, IL-1Rα, sIL-2Rα, IL-6, IL-10, IL-17, IL-18, IFN-γ, MCP-3, M-CSF, MIP-1α, G-CSF, IP-10 and MCP-1 (10). Reports suggest that IL-6, IL-8 and TNF-α attributes to SARS-related ARDS. Further, development of lung damage is likely due to elevation of inflammatory cytokine levels and CRP in SARS patients. Importantly, high levels of serum TNF-α tends to become high in patients who die of SARS-CoV-1 than in those who survive (11). However, emerging reports of SARS-CoV-2 suggests the predominance of IL-6 to TNF-α although this requires to be confirmed from multiple findings (12).
IL-6 is predominantly produced by lung epithelial cells in response to stimulatory factors similar to what has been shown for several other respiratory viruses including SARS-CoV and MERS-CoV. IL-6 is produced in a constitutive manner only upon stimuli and not by resident immune cells of the lungs, thus portraying its pleotropic and immuno-regulatory role in the respiratory mucosa. Although IL-6 is regarded as a marker of pneumonia in CoV infections, it has now become evident that abrupt release of IL-1β and TNF-α could contribute to severity of CoViD-19 pathogenesis. The onset of cytokine storm in the lung compartment likely occurs prior to recruitment of inflammatory cells, especially in allergic patients and those with other co-morbidities, leading to an exorbitant rise in mortality rates (13). A similar cytokine storm that led to severe lung injury resulting from release of 18 inflammatory mediators has been demonstrated in SARS-CoV-infected patients (14). Immune-mediated damage to the lungs and other organs, and subsequent development of multi-organ dysfunction is explained by hypercytokinemia resulting from cytokine release largely by SARS-CoV-infected ACE2-expressing cells, but not by uninfected cells (15). More recent experimental investigation has reported dramatically high levels of CXCL10, CCL5 and IL-1β in human lung epithelial cells and in the lung tissues of SARS-CoV-infected mice. The report has established that pulmonary inflammation was modulated via NLRP3 providing key clues to development of potential antiviral targets (16).
It has also been reported that individuals admitted into intensive care units have significantly elevated levels of IL-6, IL-10 and TNF-α and fewer T cells in the circulation (17). Interestingly, it has also been reported that CoViD-19 disease severity correlates positively with concomitant rise in inflammatory cytokine levels that also drive the depletion and exhaustion of SARS-CoV-2-specific CD8+ T cells (17). It has also become evident that the frequency of circulating CD4+ and CD8+ T cells are exponentially reduced, and show signs of hyperactivation i.e. elevated expression of HLA-DR and CD38. Interestingly, the hyperactive CD8+ T cells were also enriched with perforin and granulysin that potentially adds to the reported lung injury (18). More recent findings points to consistently elevated levels of CXCL10, CCL7 and IL-1 receptor antagonist and their association with increased viral load, exacerbated lung injury and a fatal prognosis.
Published data from SARS-CoV-infected patients points to an increase inuf6 TNF-α levels enhancing the migration of inflammatory cells, viz. eosinophils and neutrophils (19). A cohort of 41 laboratory-confirmed CoViD-19 patients in Wuhan, China, subjected to serological evaluation revealed high levels of IL-1β, IFN-γ, IP-10, and MCP-1, of all the 22 cytokines tested among both ICU as well as non-ICU cases. It has also become evident that in moribund cases, cytokine storm was highly associated with the magnitude of disease severity (9). Subsequent experimental data also suggests that production of TNF is mediated via NF-κB through degradation of I-κBα by CoV spike proteins (20). CoVs being predominantly zoonotic, a similar up-regulation of TNF-α has also been documented in feline CoV infection (21).
More recently, the direct involvement of the NOD-like receptor family protein (NLRp-3) inflammasome has come to light in SARS-CoV 3a culminating in the release of IL-1β via ion channel proteins called viroporins (22). In addition to the classical cytokine storm, CCL2, CXCL10, CXCL9 and CXCL8 upregulation has also been reported in uncomplicated SARS-CoV infection (22). The underlying rationale behind the far-reaching prognosis of CoViD-19 in Wuhan, China is believed to involve virus-activated cytokine storm syndrome or fulminant myocarditis, which could be related to secondary haemo-phagocytic lympho-histiocytosis (sHLH), an under-recognized ailment most commonly triggered by viral infections and sepsis, and is co-related with CoViD-19 disease (23).
The proposed cytokine storm in the pathogenesis of CoV’s could result in deleterious consequences with varying degrees of immunopathology (Figure 1). As an initial step, infiltration of airway by IFN-αβ and IFN-µ mediated by Fas-FasL-/TRAIL-DR5-dependent mechanisms leads to endothelial cell apoptosis and vascular leakage, which will be followed by TNF-mediated T-cell apoptosis resulting in suboptimal responses of T cells. Through the abrogation of STAT-1 signaling specifically in myeloid cells, activated macrophages can accumulate and alter the homeostasis of lung tissues. The final phase of cytokine assault by IL-6, CXCL8, IL-1β, and GM-CSF, CCL2, CCL5, IP-10 and CCL3 reportedly results in ARDS (24).
It must be considered that an ongoing phase of immunosenescence in the mucosa of elderly individuals deteriorates CoV severity leading to poor levels of functional T-cell subsets, antigen-specific IgA and immunological remodeling. CoVs also display neuro-virulence attributes, differentially inducing the production of pro-inflammatory mediators by astrocytes and microglial cells as shown in experimental mice (25). Intriguingly, the onset of cytokine storm in CoViD-19 disease can be hypothesized to be gender-biased as closely related MERS-CoV infection exhibited a high incidence in males than females (26). Gender-based variations in the expression of ACE2 likely could have implications in severe disease progression resulting from cytokine storm. Coding variants at specific amino acid sites are likely to be a genetic risk factor for development of severe CoViD-19, and could affect human males and females differently. Surveys conducted on the follow-up of patients SARS-CoV suggest a strong role for the involvement of cytokine storm (27).
Together, to control the askew and flared cytokine assault, and to likely alleviate lung pathology and increased survival rates, the efficacy of immuno-suppressants like actemra, IL-1β antagonists like anakinra could be investigated. Tocilizumab (a recombinant humanized anti-human IL-6 receptor monoclonal antibody) specifically binds sIL-6R and mIL-6R to inhibit signal transduction, and has been well-tolerated as established in animal drug trials (28, 29). A recently published CoViD-19 research has shown encouraging results with no evidence of any serious adverse events (30). A multicentric randomized-controlled trial of tocilizumab has been approved for CoViD-19 pneumonia (ChiCTR2000029765) (31). Application of artificial liver purification systems in addition to the rapid detection of cytokine index should be considered for implementation. Recently, an in silico docking analysis has documented curcumin, a known anti-inflammatory blockade strategy can potentially inhibit the main protease (M-Pro) of CoViD-19 (32). The importance of studies on the association between specific HLA loci/haplotypes, genetic predispositions and development of anti-SARS-CoV-2 immune responses also is urgently warranted. As a measure of restraint, it is indeed the need of the hour to discover or repurpose improved concepts for disease control as well as for alleviating the magnitude of cytokine storm syndrome in the ongoing CoViD-19 pandemic.
Biodiesel is an alternate renewable, biodegradable, non-toxic fuel similar to conventional fossil fuel. It is usually produced from vegetable oil, animal fat, tallow, non-edible plant oil and waste cooking oil. Biodiesel emits fewer air pollutants, greenhouse gases other than oxides of nitrogen and easier to treat when compared with fossil fuels. However, with all these environmental benefits, biodiesel could not be extensively used as a complete alternative fuel to conventional diesel. Accordingly in this study apart from the scope and need of biodiesel, an attempt has been made to address the number of parameters that influence the production process of biodiesel. Lipid/fat content, type and catalyst concentration, oil to alcohol ratio and other purification process has been discussed to reduce the unit operation involved in biodiesel production.
Respiratory disorders, especially non-communicable, chronic inflammatory diseases, are amongst the leading causes of mortality and morbidity worldwide. Respiratory diseases involve multiple pulmonary components, including airways and lungs that lead to their abnormal physiological functioning. Several signaling pathways have been reported to play an important role in the pathophysiology of respiratory diseases. These pathways, in addition, become the compounding factors contributing to the clinical outcomes in respiratory diseases. A range of signaling components such as Notch, Hedgehog, Wingless/Wnt, bone morphogenetic proteins, epidermal growth factor and fibroblast growth factor is primarily employed by these pathways in the eventual cascade of events. The different aberrations in such cell-signaling processes trigger the onset of respiratory diseases making the conventional therapeutic modalities ineffective. These challenges have prompted us to explore novel and effective approaches for the prevention and/or treatment of respiratory diseases. In this review, we have attempted to deliberate on the current literature describing the role of major cell signaling pathways in the pathogenesis of pulmonary diseases and discuss promising advances in the field of therapeutics that could lead to novel clinical therapies capable of preventing or reversing pulmonary vascular pathology in such patients.
Gold nanoparticles (AuNPs) have become frequently used materials in biotechnological and biomedical applications including cancer. They can be commonly synthesized by biological and chemical methods. In the present study, we synthesized Enterococcus-mediated AuNPs and evaluated their cytotoxicity in human colorectal cancer cell line (HT-29). AuNPs are synthesized intracellularly using Enterococcus sp. RMAA. Characterization of AuNPs has done using UV spectrophotometry and transmission electron microscope. Cytotoxicity was evaluated by MTT assay. Intercellular reactive oxygen species (ROS) expression and apoptosis-related morphology were evaluated by dichlorodihydrofluorescein diacetate and acridine orange/ethidium bromide staining via fluorescence microscopy. JC-1 staining and caspase 3 immunofluorescence expression were analyzed by confocal microscopy. Enterococcus sp. RMAA-mediated AuNPs are spherical and induced concentration-dependent cytotoxicity in HT-29 cells. AuNP treatments also induced ROS and caspase-3 expressions and reduced the mitochondrial membrane potential. Morphology related to apoptotic changes was also noticed after AuNP treatments in HT-29 cells. The present study revealed that Enterococcus-derived AuNPs induced apoptotic cell death in HT-29 cells and suggests that AuNPs could be used as a pro apoptotic agent for colon cancer treatment.
The mechanical performance of silica modified epoxy at various concentration of sodium hydroxide for surface treatment of multiaxial kenaf has been analyzed. Epoxy resin with amine hardener was modified with silica powder at 20 phr and toughened by treated kenaf fiber that immerses in various concentrations of sodium hydroxide (NaOH) ranging from 0% to 9% of weight. The composite was analyzed through differential scanning calorimetry (DSC) to ensure complete curing process. The mechanical properties of the composites were analyzed through flexural test, Charpy impact test and DSC to ensure the complete curing process. DSC analysis results show epoxy sample was completely cured at above 73°C that verifies the curing temperature for preparation for the composite. Hence, 3% NaOH treated composite exhibits the best mechanical properties, with 10.6 kJ/m² of impact strength, 54.1 MPa of flexural strength and 3.5 GPa of flexural modulus. It is due to the improvement of fiber-matrix compatibility. Analysis by SEM also revealed that a cleaner surface of kenaf fiber treated at 3% NaOH shown cleaner surface, thus, in turn, improve surface interaction between fiber and matrix of the composite. The composites produced in this work has high potential to be used in automotive and domestics appliances.
Fiber treatments and coupling agents have been applied by composites researchers to improve the functionality
in the flexural loading of natural fiber reinforced composites. This paper reviews how fiber treatments
upshot to flexural strength and modulus of natural fiber composites during 2000–2016. Chemical
treatments improved fiber interface bonding with matrix and impart more strengths to composites.
Coupling agents also ameliorate flexural properties and the combination of treatments is equally supercilious.
The negative impact of fiber’s physical treatments on flexural properties of natural fiber composites
also reviewed. Eventually, a number of perspectives have been concluded with the hope that our
work will succor to further betterment in flexural strength of natural fiber composites.
The aim of this paper is to study the boundary layer flow and heat transfer analysis of an unsteady viscous dusty fluid over a porous stretching surface. Momentum Boundary layer equation considers the effect of transverse magnetic field whereas thermal Boundary layer equation considers the effect of thermal radiation. The governing partial Differential equations are reduced to coupled non-linear ordinary differential equations using similarity transformation. Numerical solutions of these equations are obtained with the help of RKF-45 method. The solution is found to be dependent on different governing parameters. Some important findings reported in this work reveal that the effect of radiation has significant impact in controlling the rate of heat transfer in the boundary layer region.
The main factors that influence the properties of composite are fiber length and content. Hence the prediction of optimum fiber length and content becomes important, so that composite can be prepared with best mechanical properties. Experiments are carried out as per ASTM standards to find the mechanical properties namely, tensile strength and modulus, flexural strength and modulus, and impact strength. In addition to mechanical properties, water absorption capacity of the composite is also studied. Further, fractured surface of the specimen are subjected to morphological study using scanning electron microscope. The investigation revealed the suitability of banana fiber as an effective reinforcement in epoxy matrix.
A series of tensile tests were conducted on a Lloyd LRX tensile testing machine for numerous natural fibers deemed potential candidates for development in composite applications. The tensile tests were conducted on the fibers jute, kenaf, flax, abaca, sisal, hemp, and coir for samples exposed to moisture conditions of (1) room temperature and humidity, (2) 65% moisture content, (3) 90% moisture content, and (4) soaked fiber. These seven fibers were then tested for the four conditions and the mechanical properties of tensile strength, tensile strain to failure, and Young's modulus were calculated for the results. These results were then compared and verified with those from the literature, with some of the fibers showing distinctly promising potential. Additionally, a study on the effect of alkalization using 3% NaOH solution was carried out on flax, kenaf, abaca, and sisal to observe impact that this common fiber pre-treatment process has on fiber mechanical properties. The result of the investigation indicated that over treatment of natural fibers using NaOH could have a negative effect on the base fiber properties. It is consequently apparent that a treatment time of less than 10 min is sufficient to remove hemicelluloses and to give the optimum effect.
Aim
The purpose of this review was to determine the diagnostic accuracy of CBCT in detecting vertical root fracture in root filled teeth when compared to a reference standard (direct visualization).
Methods
Electronic searches were performed in Medline, Scopus, Cochrane and Grey Literature for English language articles till June 2020. Prospective and retrospective clinical studies using CBCT to diagnose VRF in root filled teeth were included. Case reports and in-vitro studies were excluded. Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias (RB) and applicability concerns. Meta-analysis was done using STATA 16.1 software via MIDAS 3.0 package and METANDI module. Publication bias was evaluated using Deeks funnel plot analysis. Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) was done to evaluate certainty of evidence. This systematic review was registered in the Open Science Framework (10.17605/OSF.IO/7JKE2).
Results
8 articles were included in this systematic review and meta-analysis. RB assessment showed that 5 articles in the patient selection domain had low RB with low applicability concern. In the index test and reference standard domains, 7 articles had moderate RB with moderate applicability concern. 3 articles had high RB in the flow and timing domain. There was no publication bias. CBCT had pooled sensitivity and specificity of 0.78 (95% CI =0.64-0.88) and 0.80 (95% CI =0.63-0.91) respectively and accuracy of 0.86 (95% CI =0.83-0.89). CBCT also had pooled positive and negative likelihood ratios of 4 and 0.2 respectively. In GRADE analysis, the quality of evidence was low for sensitivity and moderate for specificity when CBCT was used for diagnosis of VRF.
Conclusions
Overall quality assessment of included articles showed that in patient selection domain, the risk of bias was low and it was moderate in index test and reference standard domains. Evidence from this updated systematic review and meta analysis indicates that CBCT is still not a good tool for diagnosing VRF in root filled teeth as compared to direct visualization.
As per the demand on the fuels of vehicles alternate fuels needs were increased gradually. And also the selections of alternate fuel maximum depend on the various desirable properties. In this present investigation deals on alternate fuel such as waste tyre oil (WTO) with diesel properties like density, kinematic and dynamic viscosities identification and comparison focused. The tyre oil extracted from the waste tyre materials. There are three 50 ml increased combination of WTO used with three 50 ml decreased combination of diesel used for the measurement of properties. Each property was measured tabulated and plotted for the analysis purpose.
Composite materials have been in use since ages. The introduction of chemical revolution changed the face of composite development. However, the environmental impact of polymer composites is becoming a problem that needs to be addressed properly. This brings the situation to revive the natural composites back to day to day use by replacing them in place of synthetic composites. An attempt has been made to study about the behavior of natural composites namely aloe vera and Jute. The following mechanical properties namely ultimate tensile strength, flexural strength and impact strength as well as thermal properties namely thermal conductivity and heat deflection temperature are calculated for jute as well as aloe vera. Water absorption test is carried out to study the effect of exposure of natural composites to water. Thermogravimetric analysis is done to understand the weight loss due to temperature. Finally, all the properties are to be compared with jute and aloe vera hybrid composites.
Polymer-based materials are increasingly produced through fused deposition modelling (FDM) – an additive manufacturing process, due to its intrinsic advantages in manufacturing complex shapes and structures at low overhead costs. The versatility of this technology has attracted several industries to print complex geometrical structures. This underlines the importance of studying the mechanical strength of FDM printed polymeric materials, especially their fatigue behaviour in cyclic loading conditions. Conventionally manufactured polymeric materials (e.g. injection moulding) have superior fatigue performance than FDM printed materials. Unlike conventionally manufactured polymers, FDM-made polymers have layer by layer adhesion and the influence of printing parameters that make fatigue analysis complex and critical. The influences of printing parameters and printing material characteristics have a significant impact on the fatigue behaviour of these materials. The underlying mechanism behind the fatigue of FDM printed polymers is crucial for the assessment of these materials in structural applications. However, the fatigue behaviour of FDM printed polymeric materials has not been reviewed in detail. Therefore, this article aims to evaluate 3D printed polymeric materials’ fatigue properties. The importance of fatigue in the FDM printed biomedical materials is also reviewed, and more importantly, the novel FDM printed architected cellular material fatigue properties are also introduced.
The demand of high quality of strength mingled with the superior standards and durability leads to development of Slurry infiltrated fibrous reinforced concrete. It is a comparatively new material and can be treated as a special type of fibre reinforced concrete (FRC). It differs from normal FRC in three aspects – the fibre content, Cementitious matrix and method of production. It is made by infiltrating cement slurry into a number of bed fibres preplaced and packed tightly in the moulds. Because of its high strength, excellent energy absorption, ample stiffness and many other good properties, precast SIFCON slabs will have a wide range of structural engineering applications where high energy based elements are required. The main objective of this study is to determine the mechanical properties of slurry infiltrated fibrous concrete with multi-scale of steel fibre. The aim of present investigation is to study the flexural behaviour of SIFCON. The steel fibres used for this study is crimped type of two different length 12 and 30 mm with 8% by volume. Development of ultrahigh strength of more than 100 MPa compressive strength slurry for the preparation of SIFCON. The work on this study evaluates the mechanical properties of the SIFCON like compressive, flexural.
The present work deals with the influence of wood dust namely Rosewood and Padauk in the jute fiber-based epoxy composites. The work involves the fabrication of four different laminates of jute-epoxy composites using hand layup process with varying proportions of Rosewood and Padauk wood dust fillers compared with the composite in the absence of filler. The characterization of the mechanical and thermal properties was carried out by tensile, compression, flexural, shore D hardness, impact and thermogravimetric analysis as per ASTM. It is inferred from the test results that the mechanical properties got enhanced by the fine distribution of Padauk wood dust particles by improved adhesion with the matrix. The coarse structure of Rosewood dust over the composite improved thermal stability. Scanning Electron Microscopy was utilized to study the fractured interfaces of the mechanically tested composites. Furthermore, the developed composites affinity towards moisture and biodegradation were studied using water adsorption and biodegradability tests.
The present experimental study aims at learning the mechanical behavior of natural fiber composites. Natural fibers have an attracting the interest to engineers, researchers, professionals and scientists all over the world as an alternative reinforcement, because of its superior properties such as high specific strength, low weight, low cost, fairly good mechanical properties, non-abrasive, eco-friendly and bio-degradable characteristics. A brief review has been carried out to make use of natural fibers (such as abaca, jute, sisal, banana, cotton, coir, hemp, etc) abundantly available in India. This paper presents a review on the mechanical properties of Abaca, Jute, Sisal.
This paper aims at improving the mechanical properties of coir fiber reinforced polyester composites through impregnation of rice husk and boiled egg shell in polyester matrix. The composites sheets were manufactured by varying the fabrication parameters such as fiber length, particulate content and fiber content. The mechanical properties of the fabricated composites were determined as per ASTM standards and the effects of fiber length, particulate content and fiber content on mechanical properties of rice husk and boiled egg shells impregnated coir - polyester composites were studied. Scanning electron microscope analysis was used to characterize the fracture behavior of the composites. The investigation witnessed the improvement in mechanical properties on addition of rice husk particulate in coir fiber reinforced polyester composites. Similarly the addition of boiled egg shell in to the composites has enhanced mouldability of the composites. The SEM investigation evidenced the arrest of crack propagation and voids formation on addition of rice husk and egg shell particulates in polyester matrix. This study confirmed the possibility of using rice husk and boiled egg shell impregnated coir fiber reinforced polyester composites in low load bearing applications.
There is currently lot of work in ambient intelligence particularly in context awareness. Context awareness enables service discovery and adaptation of computing devices for ambient intelligence application. There is a common agreement of the fact that context-aware systems should be responsive to multiagents, covering a large number of devices, assisting a large number of people and serving a large number of purposes. In an attempt to achieve such context-aware systems with scalable scenario implementations, we propose an adaptive and autonomous context-aware middleware for multi-agents with Type 2 fuzzy rough context ontology. Our model provides a meta-model for context description that includes context collection, context processing and applications reactions to significant context changes.
In the present study, the effect of fiber and (5% wt) coconut shell powder (CSP) loading on the tensile properties of randomly oriented roselle fiber reinforced vinyl ester (RV) composites was carried out. Composite specimens were fabricated using the hand lay-up technique. It was observed that tensile properties of vinyl ester composites increase upon reinforcement with roselle fibers and CSP particles. The reinforcement of roselle fibers has significant effects on the tensile strength and modulus of the composite. The fractographic study was carried out on the surface of fractured composite specimens using scanning electron microscopy. A better interfacial adhesion, fiber dispersion and less fiber pull out on the surface of fractured composite specimens were identified. The tensile strength of RV composites has also been statistically analyzed by two-parameter Weibull distribution. Twenty-five tension tests were carried out. The results obtained varied between 37.89 MPa and 45.07 MPa. Furthermore, the inspection of the developed distribution was examined by the Kolmogorov-Smirnov (KS) test. The results show that the gained two-parameter Weibull distribution can be used to express the tensile strength and predict its values accurately.
The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural. Past studies show that only artificial fibers such as glass, carbon etc., have been used in fiber-reinforced plastics. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. In this connection, an investigation has been carried out to make use of coir, a natural fiber abundantly available in India. Natural fibers are not only strong and lightweight but also relatively very cheap. In the present work, coir composites are developed and their mechanical properties are evaluated. Scanning electron micrographs obtained from fractured surfaces were used for a qualitative evaluation of the interfacial properties of coir/epoxy and compared with glass fiber/epoxy. These results indicate that coir can be used as a potential reinforcing material for making low load bearing thermoplastic composites.
High flexural strength porous silicon nitride ceramics were prepared via nitridation of silicon powder, using silicon powder and Y2O3 as start powder with different forming pressures. The effects of Y2O3 contents and heating programs on nitridation rate were studied. The high nitridation rate was obtained when 9% Y2O3 was added, which was contributed to Y2O3 reacted with SiO2 at low temperature (1200 ¡䞦rpar; to transform to Y5Si3O12N and the elimination of SiO2 on Si surface. Under different sintering conditions, the porous Si3N4 ceramics with porosity of 30% ― 50% and the flexural strength of 160 ― 50MPa were obtained, respectively. After post―sintering at 175 0 ¡䟩n 0.5MPa N2 atmosphere, α―Si3N4 was fully transformed into β―Si3N4 by the solution―precipitation process, the rod―like β―Si3N4 promoted the flexural strength of the porous Si3N4 ceramics, and the porous Si3N4 ceramics with a porosity of 46% and a flexural strength of 140MPa was obtained .
Diesel Engine Emission Characteristics Study using Algae Biofuel
- Dinesh Kumar Singaravelu
Diesel Engine Performance on Chlorella vulgaris Biodiesel
- Dinesh Kumar Singaravelu
Optimization of chlorella vulgaris Biodiesel usage in Diesel Engine
- T Sathish
Mechanical and Physical Testing of Biocomposites, Fibre-Reinforced Composites and Hybrid Composites
- M Jawaid
- M Thariq
- N Saba