A Comprehensive Review on AISI 4340 Hardened Steel: Emphasis on Industry Implemented Machining Settings, Implications, and Statistical Analysis

Turning of hardened AISI 4340 steel is regarded as one of the demanding challenges in machining sectors where precision tolerances are essential for automobile parts. The AISI 4340 steel is broadly utilized in forged steel automotive crankshafts systems, hydraulic forged and additional machine tool purposes because of their improved characteristics.  Moreover, one of the keys confronts in the machining of hard 4340 steel is the comparatively deprived machining behavior that reduces the functionality of the material and further leads to component  rejection at the final inspection stage. In addition, accelerated tool wear necessitates for repeated changing of cutting tool that results in higher machining and tooling costs. This comprehensive review aimed to present in-depth features on the development of machining performances using various cutting tools. This review focus is to provide a broad perceptive of the role of controllable variables during machining of hardened steel. This review analysis examines the response variables and its advantages on chip morphology and heat generation. The comprehensive overview of machining settings, key machinability indicators and statistical analysis for AISI 4340 steel has been presented. This overview will provide academic, industrial and scientific communities with benefits and shortcomings through improved conceptual understanding towards further research and development

A comparative analysis of morphometric changes in the angle of anterior chamber after cataract surgery

Background: Cataract surgery brings about certain changes in the angle of anterior chamber and we aimed at understanding the morphometric changes occurring in the angle at the site of incision (SOI) and the site opposite to it (OSOI) after two types of cataract surgeries viz. phacoemulsification and manual small incision cataract surgery (SICS) at two postoperative follow-ups.Methods: A quasi-experimental study was conducted at AIIMS, Rishikesh and a minimum of 60 patients were enrolled. They were divided into two groups based on the surgery performed, 30 patients had undergone phacoemulsification (group A) and 30 patients had undergone SICS (group B). The patients were evaluated using optical coherence tomography (OCT), the parameters measured were central anterior chamber depth (ACD), anterior chamber angle (ACA), angle opening distance (AOD), and trabecular iris surface area (TISA). The subjects were assessed preoperatively, post-operatively at 1 week and 6 weeks.Results: The increase in the angle parameters at 1 week and 6 weeks post-operatively was found to be statistically significant in the two groups (p<0.05). The increase in the parameters was also compared between the two surgeries and was found to have no statistical difference.Conclusions: We were able to conclude that a simple cataract extraction can help treat two most common causes of blindness, cataract and glaucoma and the technique of cataract surgery used does not influence the change brought about in the angle

Grey-Fuzzy Hybrid Optimization and Cascade Neural Network Modelling in Hard Turning of AISI D2 Steel

Nowadays hard turning is noticed to be the most dominating machining activity especially for difficult to cut metallic alloys. Attributes of dry hard turning are highly influenced by the amount of heat generation during cutting. Some major challenges are rapid tool wear, lower tool-life span, and poor surface finish but simultaneously generated heat is enough to provide thermal softening of hard work material and facilitates easier shear deformation thus easy cutting. Also, plenty of works reported the utilization of various cooling methods as well as coolants which successfully retard the intensity of cutting heat but this leads to additional cost as well as environmental and health issues. However, still, there is scope to select proper cutting tool materials, its geometry, and appropriate values of cutting parameters to get favorable machining outcomes under dry hard turning and avoid the cooling cost, environmental and health issue. Considering these challenges, current work utilizes PVD-coated (TiAlN) carbide insert in dry hard turning of AISI D2 steel.&nbsp;The multi-responses like tool-flank wear, chip morphology and chip reduction coefficient are considered. Further, to get the best combination of input cutting terms, grey-fuzzy hybrid optimization (Type I and Type II) is utilized considering the Gaussian membership function. Type II grey-fuzzy system attributed to 15 % less error (between GRG and GFG) compared to Type I. Hence, Type II grey-fuzzy system is utilized to get the optimal set of input terms. The optimal combination of input terms is found as t-1 (0.15 mm), s-4 (0.25 mm/rev) and is Vc-2 (100 m/min) which is comparable to the results obtained under spray impingement cooling using CVD tool in the literature. However, hard turning can be assessed under the dry condition with a PVD tool at the obtained optimal input condition for industrial uses.&nbsp;Further, six different types of cascade-forward-back propagation neural network modelling are accomplished. Among all models, CFBNN-4 model exhibited the best prediction results with a mean absolute error of 2.278% for flank wear (VBc) and 0.112% for the chip reduction coefficient (CRC). However, this model can be recommended for other engineering modelling problems

Machinability Investigation on Novel Incoloy 330 Super Alloy using Coconut Oil Based SiO2 Nano fluid

Over the years, the quality of the finished surface has become the foremost prevalent owing to better output performance, reliability and life span of a machined part.&nbsp; Moreover, the effects of cooling and lubrication approach during the machining process play a vital role. Incoloy 330 generally used in petrochemical, chemical, power generations, thermal processing applications. This exploration focuses on the appropriate utilization of the Minimum Quantity Lubrication (MQL) based cooling approach using diverse concentrations of coconut oil based SiO2 nanofluids in the turning practice of Incoloy 330 alloy. The input variables are nanofluids concentration (Nc), feed (f) and cutting speed (Vc). The cutting insert TiAlN PVD coated cemented carbide tool is utilized to study the output responses like tool flank wear (VBc), surface roughness (Ra), material removal rate (MRR), and chip morphology. SiO2 nanofluids work effectively as tool flank wear is found to be less (VBc varies in between 0.057 mm to 0.077 mm). From ANOVA, cutting speed is found to be topmost influencing input (83.24%) for tool flank wear. Machining on the highest feed value (0.35 mm/rev) is not recommended for this work as Ra is found to be greater than 1.6 µm. With increasing cutting speed and feed rate, MRR increases. In each run, coiled continuous helical chips are obtained. Deformed chip thickness is found to be lower ( 0.3 to 0.74 mm) due to the application of SiO2 nanofluid through MQL which enhanced the heat dissipation thus eliminated the tendency of chip welding on the top surface of the tool. Chip reduction coefficient decreases with feed and cutting speed. Further, the TOPSIS optimization technique has been implemented to get an optimum set of cutting parameters for multiple responses and it is found to be Nc3 (0.3 % wt)-f1 (0.15 mm/rev)-Vc3 (160 m/min)

Comparative Analysis of Mechanical and Water Absorption Properties of Nano/micro-sized Alumina Filler Based Glass-Jute Hybrid Composites

In recent years, the addition of nano and micro size filler material for fabricating composite materials are emerging concept through which mechanical properties of the composite can be enhanced. Filler based hybrid polymer composite materials are substituting metallic materials because of their low specific wear rate, high specific strength modulus, and less water absorption. In current work, nano and micro Al2O3 filler based Glass-Jute hybrid composite have been fabricated to study the mechanical properties like hardness, impact test, specific wear rate, and flexural strength for each type of composite sample. Water absorption analysis is also carried under three different fluid media namely normal water, river water and de-ionized water-based Al2O3 nanofluid. Nano filler enriched composite attributed the higher magnitudes of hardness, impact strength, flexural strength and lower value of specific wear rate and water absorption compared to micro and normal composites.&nbsp;However, a nanofiller based composite is more suitable for automotive, aerospace and ship manufacturing industries

MQL assisted cleaner machining using PVD TiAlN coated carbide insert: Comparative assessment

311-325Minimum quantity lubrication (MQL) is an alternative over dry machining due to economic and ecological sustainability. In the current research, a comparative investigation has been carried out on machinability and surface integrity aspects of hardened AISI 4340 steel using PVD TiAlN coated carbide inserts during dry and MQL assisted hard turning. Under the dry condition, turned surface has been encountered tensile residual stress whereas compressive residual stress has been generated under MQL condition. Formation of a white layer on the chip has not been experienced under both conditions. Cutting speed predominantly influences tool wear and feed influences more on surface roughness. Dimensional deviation and auxiliary flank wear have been significantly reduced under MQL condition with 16.21% cost savings. An improvement in machinability characteristics and surface integrity under MQL cutting has been noticed compared to dry with favorable interaction and contribute towards cleaner machining process. This may be adopted in machining shop floor as a good replacement over dry machining

Pattern of Cancer in Nepal from 2003 to 2011

Correction: On 15th January 2017, the authors Sunil Kumar Sah and Naval Kishor Yadav were added to the author list.Cancer is global burden of disease in developed and developing countries. It is one of the main causes of death. The environmental factor and life styles are major causes of cancer.This hospital based retrospective study was carried out using data retrieved from the register maintained at seven cancer centers. The most common basis of diagnosis were microscopic (histopathological and cytopathological examination). The diagnosis was also based on clinical examination, radiological examination, endoscopy, biochemical and immunological tests.Most of the cancer cases were diagnosed at BPKMCH (23908) followed by BPKIHS (9668) and BH (5959) and few cases from KCH (518) in 2003 to 2011. The total number of cancer cases were increasing from 2003 to 2011 and it become double in 2011. Out of 75 district of Nepal, more number of cancer cases was found in Kathmandu, Sunsari, Morang, Chitwan, Lalitpur, Jhapa, Kaski, Nawalparasi, Rupendehi and Kavrepalchowk in 2010. Similarly, in 2011 more number of cancer cases was found in Kathmandu, Morang, Jhapa, Sunsari, Chitwan, Lalitpur, Rupendehi, Kaski, Saptari, Bhaktapur. Lung cancer was the common cancer and similarly, other prevalent cancers were cervical, breast, stomach, ovarian and colo-rectum cancer in 2003 to 2011. The common cancers were lung, cervical, breast, stomach, ovarian and colo-rectum. The number of patients is increasing, which may be due to change in life style and lack of education

Biomass derived carbon nanoparticle as anodes for high performance sodium and lithium ion batteries

In this paper, we report a flame deposition method to prepare carbon nanoparticles (CNPs) from coconut oil. The CNPs were further modified with a piranha solution to obtain surface-carboxylated carbon nanoparticles (c-CNPs). When used as an anode for sodium-ion batteries, the CNPs and c-CNPs respectively delivered discharge capacities of 277 and 278 mA h g in the second cycle at a current density of 100 mA g. At the 20th cycle, the capacities of CNP and c-CNPs were 217 and 206 mA h g respectively. The results suggest that modification of the CNPs with the piranha solution improved neither the charge storage capacity nor the stability against cycling in a sodium-ion battery. When the CNP and c-CNP were used an anode in a lithium-ion battery, 2nd-cycle discharge capacities of 741 and 742 mA h g respectively at a current density of 100 mA g were obtained. After 20 cycles the capacities of CNP and c-CNP became 464 and 577 mA h g respectively, showing the cycling stability of the CNPs was improved after modification. The excellent cycling performance, high capacity and good rate capability make the present material as highly promising anodes for both sodium-ion and lithium-ion batteries