Parametric optimization of fatigue behaviour of hybrid aluminium metal matrix composites

For various aerospace applications aluminium has emerged as most preferred material due to desirable attributes such as superior strength to density ratio, greater specific strength, better corrosion resistance, high toughness and cost effectiveness. The most desirable characteristics for aerospace materials are ability to withstand elevated temperature and sustain higher fatigue loadings. Current experimental investigation was carried out to explore and optimize fatigue characteristics of hybrid composites developed by infusing particulate reinforcements into aluminium alloy. Eggshell particles (wt% 0.5, 1 and 1.5, average particle size approximate to 60 mu m), Silicon Carbide particles (wt% 1, 1.5 and 2, average particle size approximate to 65 mu m) and Aluminium Oxide particles (wt% 1.5, 2 and 2.5, average particle size approximate to 90 mu m) were reinforced into Al 7075-T6 metal matrix through electromagnetic stir casting route as per L9 orthogonal array of Taguchi's approach in order to synthesize hybrid aluminium metal matrix composites with enhanced fatigue resistance. Analysis of variance (ANOVA) was also conducted to observe the effect of different process parameters on fatigue life of developed composites. Nine hybrid composite specimens and one as-cast Al7075-T6 specimen (in three replications) were prepared in accordance with ASTM E 468/606 and were evaluated for low cycle fatigue resistance at a constant load of 2 kg and constant speed of 500 rpms on rotating beam fatigue testing machine. It was observed that at 30 degrees C temperature, hybrid composite specimens exhibited significant enhancement in fatigue resistance in terms of reversible load cycles survived. The as-cast Al 7075-T6 specimen sustained only 94 load cycles while the highest number of load cycles i.e. 4560 were survived by hybrid composite specimen with Al 7075-T6 as base metal reinforced with 1.5 wt% of eggshell particles, 1.5 wt% of SiC particles and 1.5 wt% of Al2O3 particles (total reinforcement content only 4.5%) and mechanically stirred for 360 s

Aluminium metal matrix composites: A retrospective investigation

Aluminium matrix composites (AMMCs) are considered to be new generation potential materials for many engineering applications. Different kinds of reinforcement have been infused into the aluminium matrix in order to improve hardness, toughness, stiffness, wear resistance, fatigue properties, electrical properties and thermal stability as compared to their conventional unreinforced counterparts. The characteristics of AMMCs depend largely upon the type of reinforcement materials, interface bonding and processing parameters. In this article we have attempted to investigate the development of aluminium metal matrix composites (AMMCs) along with associated challenges and significant application areas

High-risk human papillomavirus-associated corneal/conjunctival intraepithelial neoplasia in a young patient

PURPOSE: To report a case of high-risk human papillomavirus (HPV)-associated corneal/conjunctival intraepithelial neoplasia (CIN) in a 17-year-old fair-skinned male with no other risk factors. OBSERVATIONS: A 17-year-old Caucasian male presented with an 18-month history of left eye pain, redness, itchiness, and decreased vision. Examination revealed a leukoplakic nasal limbal/peripheral corneal lesion resistant to topical antibiotic and anti-inflammatory treatments. Excisional biopsy confirmed the diagnosis of CIN, and RNA in situ hybridization testing for high-risk HPV types 16/18 was positive. Subsequent testing of the patient for human immunodeficiency virus (HIV) returned negative. CONCLUSIONS AND IMPORTANCE: The median age of CIN diagnosis in the United States is in the sixth decade of life and is usually associated with a history of ultraviolet (UV) light exposure. There are reports of CIN in young patients with systemic immunodeficiency, immunosuppression, xeroderma pigmentosum, atopic dermatitis, asthma, and vaping. Here we present a case of high-risk HPV-associated CIN in a young, fair-skinned patient with no other identifiable risk factors

Morphological, Morphometric, and Molecular Characterization of Intraspecific Variations within Indian Populations of Meloidogyne graminicola

Fourteen populations of Meloidogyne graminicola were collected from different agroecological regions of India. Morphological and morphometrical comparisons were made for various nematode life stages. Three populations (Hisar, New Delhi, and Samastipur) were different from typical M. graminicola on the basis of the length of eggs; J2 length, a-value, hyaline tail portion; male length, distance up to excretory pore, spicule and gubernaculum lengths; female length and width, stylet length, distance up to excretory pore, EPST (distance of excretory pore from anterior end / stylet length [females]) ratio, and vulval length. Morphological and morphometrical comparison with closely related species M. graminis, M. oryzae, M. salasi, M. triticoryzae, and M. lini clustered these populations into two groups: Anand, Bhubaneswar, Hyderabad, Jammu, Jorhat, Kalyani, Kanpur, Ludhiana, Mandya, Palampur, Vellayani grouped with M. graminicola, M. triticoryzae and M. salasi; whereas, Hisar, New Delhi, Samastipur grouped with M. oryzae and M. graminis. Molecular phylogenetic analysis using internal transcribed spacer (ITS) suggested that in spite of morphological differences, these populations belonged to M. graminicola

Variability assessment and construction of infectious clone of Indian Apple Scar Skin Viroid

Apple scar skin viroid (ASSVd) is widely distributed and economically important pome-fruit infecting viroid belonging to the genus Apscaviroid. It causes huge economic losses to the apple industry. Apple fruits with dappling, scarring, cracking and deformation symptoms were noticed during survey of apple growing regions of Himachal Pradesh, India. ASSVd was detected from four isolates showing dappled fruits. Molecular characterization of the viroid was done. Ten clones each from five isolates were sequenced out of which seven new sequence variants of ASSVd were found. Four of the clones were 330 nucleotides (nt) long and the other eight had an additional nucleotide. The clones showed significant sequence variability (94-100%) with each other. Variability was more common in the pathogenic domain of the viroid genome. Present isolates grouped with some Chinese and Korean isolates in phylogenetic analysis. The study reports seven new sequence variants of ASSVd and also gives a first molecular evidence of a viroid infection (ASSVd) in apple from India. Infectious clone of ASSVd were constructed for in vitro mutagenic studies. Keywords: Apple scar skin viroid, cloning, DNA sequencing, phylogenetic analysi

Image Harvest: an open-source platform for high-throughput plant image processing and analysis

High-throughput plant phenotyping is an effective approach to bridge the genotype-to-phenotype gap in crops. Phenomics experiments typically result in large-scale image datasets, which are not amenable for processing on desktop computers, thus creating a bottleneck in the image-analysis pipeline. Here, we present an open-source, flexible image-analysis framework, called Image Harvest (IH), for processing images originating from high-throughput plant phenotyping platforms. Image Harvest is developed to perform parallel processing on computing grids and provides an integrated feature for metadata extraction from large-scale file organization. Moreover, the integration of IH with the Open Science Grid provides academic researchers with the computational resources required for processing large image datasets at no cost. Image Harvest also offers functionalities to extract digital traits from images to interpret plant architecture-related characteristics. To demonstrate the applications of these digital traits, a rice (Oryza sativa) diversity panel was phenotyped and genome-wide association mapping was performed using digital traits that are used to describe different plant ideotypes. Three major quantitative trait loci were identified on rice chromosomes 4 and 6, which co-localize with quantitative trait loci known to regulate agronomically important traits in rice. Image Harvest is an open-source software for high-throughput image processing that requires a minimal learning curve for plant biologists to analyze phenomics datasets. Supplementary files (2) attached below

Microstructure and Wear Study of Al 7075-T6/Eggshell/SiC/Al2O3 Hybrid Composites

In present experimental investigation, hybrid aluminium metal matrix composites were fabricated using stir casting technique by infusing eggshell particles (0.5, 1 wt%), SiC particles (1, 1.5 wt%) and Al2O3 particles (1.5, 2.5 wt%) into Al 7075-T6 metal matrix. The developed composites were further characterized for microstructures using FESEM, X-ray diffractometry and EDS techniques. Tribological behaviour investigations were carried out using a pin-on-disk tribometer for comparative study between as-cast Al 7075-T6 alloy and Al-7075-T6/Eggshell/SiC/Al2O3 composites. During dry sliding wear test at room temperature, there was a decrease of 33% in wear rate, 20% in coefficient of friction and 20% in frictional force of composites, whereas in presence of lubricant, the developed composites exhibited maximum reduction of 85% in wear rate, 46% in coefficient of friction and 46% in frictional force as compared to their unreinforced counterparts. Due to augmented tribological properties, fabricated hybrid composites can reasonably be used for lightweight wear-resistant applications

Simulation of Single Phase 3-level Z-source NPC Inverter with PV System

This paper elucidates simulation of single phase 3-level z-source neutral point clamped (NPC) inverter with PV system. single phase NPC inverter employed due to its advantages like less voltage stress, reduced harmonic content, minimsed CMV and voltage stress is low. Z-source network is engaged to boost input voltage getting from the photovoltaic system, which is manoeuvre in shoot through and non-shoot through conditions. This proposed scheme utilized to enhance the output voltage, minimise THD and the leakage current can be avoided with help of split inductor connected with output of inverter system. sinusiodal pulse width modulation (SPWM) used as control technique for the proposed 3-level z-source NPC inverter. The simulation results of this scheme has been verified using matlab/simulink