Manipal Academy of Higher Education

Thermal and Acoustic Properties of Flax and Hemp Epoxy Bio-Composites Fabricated Using Vacuum-Assisted Resin Infusion Moulding

Synthetic fibre composites deliver high mechanical performance at a substantial energy and carbon cost, motivating a shift to renewable reinforcements. Flax and hemp are credible candidates, but their uptake is constrained by thermal stability and inherent combustibility, and the...

Influence of stem geometry and material combinations on the biomechanical and tribological performance of hip implants using finite element analysis

Abstract This study investigate the biomechanical behavior and wear characteristics of different hip implant geometries and materials using finite element analysis (FEA). Total hip arthroplasty (THA) success critically depends on design, which influences stress distribution, dura...

Bounded-index nilpotent subgroups of rational linear groups with finitely many automorphism orbits

Let \(G\leq\operatorname{GL}_n(\mathbb Q)\) have finitely many orbits under its full abstract automorphism group, and put \(d=\dim_{\mathbb Q}\operatorname{span}_{\mathbb Q}G\). We prove that \(G\) has a torsion-free normal subgroup \(U\) satisfying \[ \gamma_n(U)=1,\qquad [G:U]\...

An involutory automorphism of a double cover of A8 with central fixed involutions

We construct a finite perfect group \(E\) with centre \(\{1,z\}\) and \(E/\langle z\rangle\cong A_8\), together with an automorphism \(\alpha\) of order two satisfying \[\{g\in C_E(\alpha):g^2=1\}=\{1,z\}.\] The group \(E\) contains a subgroup isomorphic to \(C_2\times C_2\), so...

Nonunique indecomposable projective decompositions over the localized group ring of PSL2(F11)

Put \(O=\mathbb Z_{(11)}\) and \(G=\operatorname{PSL}_2(\mathbb F_{11})\). We construct nonzero finitely generated indecomposable projective \(O[G]\)-modules \(A,B,C,D\), each of \(O\)-rank \(44\), with \[A\oplus D\cong B\oplus C,\qquad A\not\cong B,\qquad A\not\cong C.\] Thus a...

Development of a penalized clinical risk score for oral squamous cell carcinoma

Abstract Introduction Prompt diagnosis of Oral Squamous Cell Carcinoma (OSCC) is key to favorable outcomes, but in low- and middle-income settings, constrained access to timely histopathology and imaging often leads to delayed detection. The NDB UFES dataset provides demographic,...

Divisible subgroups as exact equalizers in torsion-free nilpotent groups

Let \(G\) be torsion-free nilpotent of class at most \(c\), and let \(H\leq G\) be divisible. We construct a torsion-free nilpotent group \(K\) of class at most \(c\) and embeddings \(f_0,f_1:G\hookrightarrow K\) whose equalizer is exactly \(H\). Consequently the dominion of \(H\...

An irreducible nonmonomial representation of degree eight in a semiabelian group of order 2592

We construct a semiabelian group \(G\) of order \(2592\) with an irreducible complex representation of degree eight which is not induced from a linear character of any subgroup. Write \(M=C_2^3\rtimes A_4\) as a signed permutation group and choose \(K\leq M\) with \(K\cong Q_8\rt...

Nonclosed powers of a Zariski-closed subset of GL₃ in characteristic five

We construct a Zariski-closed subset \(Y\) of \(\mathrm{GL}_3(\overline{\mathbb F_5(u)})\) containing the identity such that \(Y^m\) is not closed for every integer \(m\geq2\). The same diagonal matrix lies in \(\overline{Y^m}\setminus Y^m\) for all such \(m\). The construction u...

Nonclosed powers of a Zariski-closed subset of GL₃ in characteristic five

We construct a Zariski-closed subset \(Y\) of \(\mathrm{GL}_3(\overline{\mathbb F_5(u)})\) containing the identity such that \(Y^m\) is not closed for every integer \(m\geq2\). The same diagonal matrix lies in \(\overline{Y^m}\setminus Y^m\) for all such \(m\). The construction u...

Free products of free-group automorphism groups: a finite-rank embedding by separating cocycles

Let \(I\) be finite and let \(G_i\leq\operatorname{Aut}(F_{n_i})\), where the ranks \(n_i\) may vary with \(i\). We construct an embedding \(\mathop{\ast}_{i\in I}G_i\hookrightarrow\operatorname{Aut}(F_{\sum_i n_i+|I|+1})\). For two factors this gives \(G*H\hookrightarrow\operato...

Palindromic length in free groups through reflection length and noncrossing matchings

We express palindromic length in a finitely generated free group as the minimum of two reflection lengths in a universal Coxeter group. The identity converts optimal reflection factorizations into optimal palindromic factorizations. Combined with the classical cancellation-norm r...

A non-concise formula in the integer Heisenberg group

A first-order formula in the language of groups is concise in a class of groups if, in every group in that class, finiteness of its solution set implies finiteness of the subgroup generated by that set. We give a parameter-free positive formula with one free variable that is not...

Punctured point spectrum of a four-regular bipartite Cayley graph

Let \(G=\langle a,t\mid a^3=t^2=1\rangle\) and \(S=\{a^ita^j:1\le i,j\le2\}\). The Cayley graph \(\Gamma=\operatorname{Cay}(G,S)\) is infinite, connected, simple, four-regular, bipartite and vertex-transitive. Its adjacency operator on \(\mathbb C^G\) has point spectrum exactly \...

Palindromic length in free groups through reflection length and noncrossing matchings

We express palindromic length in a finitely generated free group as the minimum of two reflection lengths in a universal Coxeter group. The identity converts optimal reflection factorizations into optimal palindromic factorizations. Combined with the classical cancellation-norm r...

First-order separation of pro-orderable groups from a bi-orderable matrix group over Z[F₂]

Let \(\mathcal O\) be the class of bi-orderable groups and let \(\mathcal O^*\) consist of the groups in which every bi-invariant partial order extends to a bi-invariant total order. We construct a countable upper triangular matrix group \(H\) over \(\mathbb Z[F_2]\) and a senten...

Effectiveness of two different innovative teaching learning methods: a comparative analysis among phase 1 MBBS students

Abstract Background Active learning strategies are increasingly incorporated into competency-based medical education to promote student engagement, collaborative learning, and higher-order cognitive skills. Although both cooperative learning methods have demonstrated educational...

Thermohydraulic performance enhancement of a solar air heater integrating jet impingement and semi-cylindrical side-wall modification within a dual-chamber configuration: a combined experimental and numerical investigation

This work introduces a novel hybrid solar air heater (SAH) architecture that combines jet impingement and semi-cylindrical side-wall geometry modifications within a dual-chamber duct to simultaneously exploit active and passive augmentation mechanisms. A systematic parametric stu...

A non-concise formula in the integer Heisenberg group

A first-order formula in the language of groups is concise in a class of groups if, in every group in that class, finiteness of its solution set implies finiteness of the subgroup generated by that set. We give a parameter-free positive formula with one free variable that is not...

Finite first-order recognition of freeness from subsemigroup lattices

Let \(\mathcal L(S)\) be the lattice of all subsemigroups of a nonempty semigroup \(S\), including the empty subsemigroup. There are sentences \(\Phi_{\rm fr}\) and \(\Phi_{\rm ab}\) in the language \(\{\wedge,\vee\}\) such that \(\mathcal L(S)\models\Phi_{\rm fr}\) exactly when...