Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The rate of heat generation and plastic deformation of materials should be precisely controlled in order to get a strong and sound weld joint during dissimilar friction stir lap welding (FSLW) of aluminium and steel. The effect interfacial microstructure at the weld joint interface on mechanical properties is elucidated in the present investigation with the help of detailed microstructure evaluation in FSLW of AA6061 and mild steel (MS). The results indicated a substantial variation in interfacial structure from formation of a bi-metallic straight interface, intercalated structure to mechanically mixed zone (MMZ) with the increase in tool rotation speed from 300 rpm to 1700 rpm. In addition, significant differences in the microstructure evolution mechanisms were noticed from the AA6061 side to MS side through the interfacial microstructure. The variation in interfacial structure and corresponding change in the fracture location predominantly affected the mechanical properties of the joints at different tool rotation speeds. The fracture locations in MMZ and intercalated structure showed the highest and lowest lap shear strengths, respectively. © 2020 Elsevier Inc.

World University root node

Department of Mechanical Engineering

Materials Characterization

Elucidation of interfacial microstructure and properties in friction stir lap welding of aluminium alloy and mild steel

Girth friction welding is a novel technique to join co-axial linepipes with an external ring (girth) in solid state and without melting of materials. The ring or the girth is rotated between two pipes under an axial force resulting in frictional heat generation and plastic deformation along the pipe-girth interfaces. The rotation of the girth is stopped after a preset displacement of the pipes while the force is maintained to consolidate the deformed material and form the joint along the girth-pipe interfaces. Since the girth is only rotated and the pipeline sections remain stationary, the process simplifies the in situ assembly operations and enables the joining of complex configurations. As the melting of pipes and girth is avoided, the formation of harmful intermetallic compounds and deterioration of toughness in the heat affected zone are minimized. A comprehensive numerical model is reported in the present work to analyse the influence of key process variables on the rate of heat generation, resulting temperature field and thermal cycles, and the nature of material flow along the pipe-girth interfaces in girth friction welding of duplex stainless steel pipes. The computed results of thermal cycles and joint shapes are validated with the corresponding experimentally measured results. The results showed a favorable balance of the ferrite and austenite phases, and very little presence of the harmful sigma phases in the recrystallized weld-zone, which is difficult in fusion welding processes of similar materials. © 2020

Journal of Manufacturing Processes

An investigation on girth friction welding of duplex stainless steel pipes

Use of fibre reinforced concrete (FRC) for pavements is advocated since the higher crack resistance could lead to lower slab thickness and higher joint spacing. The post-cracking capacity of FRC allows pavements to be designed and analysed considering the response beyond the elastic regime. The current paper presents possible failure patterns in FRC pavement slabs, which are governed by the slab dimensions, loading type and boundary conditions and the appropriateness of inelastic design methodologies for these failure patterns. Subsequently, a mechanistic-empirical design methodology developed for FRC pavements, based on yield line analysis incorporating fatigue in the moment calculation, is discussed. The proposed design methodology gives specific checks for the different failure patterns and the consequent design strategy to be adopted. The method incorporates material parameters, such as the first crack and post crack flexural strengths and fatigue correction factors for the evaluation of the moment carrying capacity. Cumulative fatigue damage analysis is also done as a serviceability check. The final design solution satisfies both the inelastic moment capacity requirement and fatigue life required without excessive damage accumulation.

Environmental Sciences and Sustainable Engineering Centre (ESSENCE)

Sadhana - Academy Proceedings in Engineering Sciences

Mechanistic-empirical design of fibre reinforced concrete (FRC) pavements using inelastic analysis

Level of Service (LOS) indicates the operational efficiency of traffic facilities. The method recommended by Highway Capacity Manual (HCM) for signalized intersections uses control delay as the service measure and does not incorporate users’ perception. As LOS is a measure of customer satisfaction, it is important to incorporate users’ perceptions into it. This paper attempts to evaluate the influence of user’s vehicle class on perceived LOS at signalized intersections under heterogeneous traffic conditions. An extensive user perception survey involving approximately 8500 users in motorized two wheelers, three wheelers, cars, and buses at 15 signalized intersections across India populates the database. From the model results, it has been concluded that along with perceived waiting time, other perception-related factors have significant effect on the users’ perceived LOS. The findings highlight the necessity of incorporating qualitative parameters in LOS analysis in addition to the conventional service measure (i.e. delay). © 2020, © 2020 Hong Kong Society for Transportation Studies Limited.

Department of Civil Engineering

Transportmetrica A: Transport Science

Perceived level of service at signalized intersections under heterogeneous traffic conditions

This paper explores the power of catalytic computation when the catalytic space (c(n), the full memory for which the content needs to be restored to original content at the end of the computation) is much more than exponential in the pure space (s(n), the empty memory which does not have any access/restoration constraints). We study the following three regimes of the relation between s(n) and c(n) and explore the class in each of them. Low-end regime: We define the classes and (nondeterministic variant of) where and. Exploring the connection between computational power of one counter machines (OC) and constant pure space catalytic Turing machines, we observe that and show that. We prove that Low-end non-constant regime: Let M be an oblivious catalytic Turing machine using s(n) pure space and c(n) catalytic space such that then L(M) is regular. This strengthens the classical theorem on to the case of catalytic Turing machines.High-end regime: We show an implementation of incremental dynamic program using catalytic machines, thus showing that Knapsack problem (with n items, sum of their costs as C and the capacity of the bag as K) can be solved in pure space and catalytic space. Hence, catalytic algorithms can lead to a non-trivial saving in the pure space required for computation when K is. Our techniques include interesting generalizations of crossing sequence arguments and implementations of incremental dynamic programs using catalytic algorithms. These may be of independent interest. © 2020, Springer Nature Switzerland AG.

Department of Computer Science and Engineering

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

On Pure Space vs Catalytic Space

In this paper, we study the Boolean function parameters sensitivity (s), block sensitivity (bs), and alternation (alt) under specially designed affine transforms and show several applications. For a function f:F2n→{−1,1}, and A=Mx+b for M∈F2n×n and b∈F2n, the result of the transformation g is defined as ∀x∈F2n,g(x)=f(Mx+b). As a warm up, we study alternation under linear shifts (when M is restricted to be the identity matrix) called the shift invariant alternation (the smallest alternation that can be achieved for the Boolean function f by shifts, denoted by salt(f)). By a result of Lin and Zhang (2017) [7], it follows that bs(f)≤O(salt(f)2s(f)). Thus, to settle the Sensitivity Conjecture (∀f,bs(f)≤poly(s(f))), it suffices to argue that ∀f,salt(f)≤poly(s(f)). However, we exhibit an explicit family of Boolean functions for which salt(f) is 2Ω(s(f)). Going further, we use an affine transform A, such that the corresponding function g satisfies bs(f,0n)≤s(g). We apply this in the setting of quantum communication complexity to prove that for F(x,y)=deff(x∧y), the bounded error quantum communication complexity of F with prior entanglement, Q1/3⁎(F) is Ω(bs(f,0n)). Our proof builds on ideas from Sherstov (2010) [17] where we use specific properties of the above affine transformation. Using this, we show the following. (a) For a fixed prime p and an ϵ, 0&lt;ϵ&lt;1, any Boolean function f that depends on all its inputs with degp(f)≤(1−ϵ)log⁡n must satisfy [Formula presented]. Here, degp(f) denotes the degree of the multilinear polynomial over Fp which agrees with f on Boolean inputs. (b) For Boolean function f such that there exists primes p and q with degq(f)≥Ω(degp(f)δ) for δ&gt;2, the deterministic communication complexity - D(F) and Q1/3⁎(F) are polynomially related. In particular, this holds when degp(f)=O(1). Thus, for this class of functions, this answers an open question (see Buhrman and de Wolf (2001) [15]) about the relation between the two measures. Restricting back to the linear setting, we construct linear transformation A, such that the corresponding function g satisfies, alt(f)≤2s(g)+1. Using this new relation, we exhibit Boolean functions f (other than the parity function) such that s(f) is Ω(sparsity(f)) where sparsity(f) is the number of non-zero coefficients in the Fourier representation of f. This family of Boolean functions also rule out a potential approach to settle the XOR Log-Rank conjecture via the recently settled Sensitivity conjecture (Hao Huang (2019) [5]). © 2020 Elsevier B.V.

Fulltext

Theoretical Computer Science

Sensitivity, affine transforms and quantum communication complexity

For a domain D ⊂ Cn, n ≥ 2, let FkD(z) = KD(z)λ(IkD(z)), where KD(z) is the Bergman kernel of D along the diagonal and λ(IkD(z)) is the Lebesgue measure of the Kobayashi indicatrix at the point z. This biholomorphic invariant was introduced by Błocki. We study its limiting boundary behaviour on two classes of domains: h-extendible and strongly pseudoconvex polyhedral domains. © Instytut Matematyczny PAN, 2020.

Department of Mathematics

Annales Polonici Mathematici

Further remarks on the higher dimensional suita conjecture

Additive manufacturing (AM) is a rapidly developing technology in biomedical, aerospace and automobile industries. However, adoption of this technology on a larger production scale remains limited. This is primarily due to the drawbacks of present AM processes associated with achievable dimensional accuracy and surface integrity of the fabricated component. The average surface roughness (Ra) of the component ranges from 3 μm to 10 μm with stair-stepping effects, balling on surfaces resulting in poor dimensional accuracy. Therefore, post-processing methods like abrasive flow finishing, laser polishing, chemical polishing and traditional finish machining is often used to meet the desired surface integrity and accuracy. However, some of these post-processing methods are quite expensive leading to overall increase in the production cost of the component. On the other hand, methods like etching and sand blasting are time consuming and not suitable for component with intricate geometries. In this paper, low energy wire electrical discharge polishing (WEDP) has been employed to achieve the desired surface integrity and finish. Initially, experiments were conducted to analyse the finishing achieved on planer additive manufactured stainless steel (SS316L) specimens. A significant reduction in roughness of maximum 80 % was obtained at various settings for pulse on time and servo voltage. In addition, SEM and EDS analysis were also carried out to study the microstructure and composition after WEDP. From the study, it was found that the WEDP process is a promising method to finish metallic AMed components. © 2020 The Author(s).

Procedia CIRP

Wire electrical discharge polishing of additive manufactured metallic components

Spark Erosion Machining: MEMS to Aerospace

Spark Erosion Based Hybrid Processes

In recent years, Coarse Grain Reconfigurable Architecture (CGRA) accelerators have been increasingly deployed in Internet-of-Things (IoT) end nodes. A modern CGRA has to support and efficiently accelerate both integer and floating-point (FP) operations. In this paper, we propose an ultra-low-power tunable-precision CGRA architectural template, called TRANSprecision floating-point Programmable archItectuRE (TRANSPIRE), and its associated compilation flow supporting both integer and FP operations. TRANSPIRE employs transprecision computing and multiple Single Instruction Multiple Data (SIMD) to accelerate FP operations while boosting energy efficiency as well. Experimental results show that TRANSPIRE achieves a maximum of 10.06× performance gain and consumes 12.91× less energy w.r.t. a RISC-V based CPU with an enhanced ISA supporting SIMD-style vectorization and FP data-types, while executing applications for near-sensor computing and embedded machine learning, with an area overhead of 1.25× only. © 2020 EDAA.