arXiv subjects

Ajay Vallabh

Publications and source records attributed to Ajay Vallabh.

3 recordsLinked to original sources

arXiv2026

DynaMate2: runtime registration of expert-defined tools for agentic scientific workflow automation

Agentic large-language-model systems can coordinate scientific tools, but many implementations remain difficult for domain scientists to extend without modifying the source orchestration code or relying on unconstrained code generation. DynaMate2 is a LangGraph-based multi-agent framework for converting expert-defined Python functions into persistent AI-callable tools. The architecture separates domain execution from LLM supervision: registered tools perform scientific operations, while a supervisor LLM decomposes goals, selects specialist agents, routes inputs, and propagates outputs across steps. DynaMate2 supports: runtime tool registration from inline code, source files, and explicitly requested natural-language specifications; persistent storage of tools, agents, and conversation state; and a web interface for interactive workflow assembly. We demonstrate the framework on a molecular simulation workflow in which a single instruction retrieves a MACE foundation model, builds a NaCl-water configuration, runs an ASE molecular dynamics trajectory, and generates energy and temperature diagnostics. The demonstration illustrates how validated workflow components can be composed into a supervised agentic pipeline without rewriting the framework. DynaMate2 therefore provides a reusable template for extending LLM-based automation to research groups with existing Python workflows, while preserving the need for explicit tool validation, reproducibility logs, and deployment-specific safeguards.

physics.chem-ph↗

arXiv2024

The Role of a Diluent in Deformation-Induced Bonding of Glassy Polymer Bidisperse Blends

Bonding between polymers below the glass transition temperature through molecular-scale dilatation (or densification)-based interdiffusion of macromolecules has recently been introduced. In this mechanism, short timeframe plastic deformation enables polymer chains to interdiffuse and form entanglements at the interface, facilitating rapid bonding below the glass transition temperature ($T_g$). Here, we are addressing the role of a lower molecular weight diluent in bonding polymer interfaces of bidisperse blends through deformation-induced bonding (DIB) at temperatures well below both the surface and bulk glass transition temperatures, $T_g^s$ and $T_g^b$, respectively, by using molecular simulations. These simulations reveal that addition of the diluent ($ϕ\le$20\%) drastically enhances the number of chain-ends at the interfacial region compared to a pure glass sample ($ϕ=0\%$) during deformation below $T_g^s$, which improves the possibility of opposite side entanglement formation. The changes in stress-strain response of debonded samples correlate with the normalized entanglement density. Likewise, the maximum interfacial fracture energy $G_{I,max}$ of debonded samples is correlated with the diluent concentration ($ϕ$), below $T_g^s$. Furthermore, the optimization of material and process conditions for DIB has yielded a notable advancement for the conditions tested here: achieving a higher bonding strength, approximately one-third of the bulk, all while remaining below $T_g$.

cond-mat.soft↗

arXiv2022

Dilatational-Plasticity Opens a New Mechanistic Pathway for Macromolecular Transport Across Polymeric Interfaces Yielding Solid-State Bonding

Bonding between polymeric interfaces is encountered widely in several industrial applications. Many of these bonding processes rely on time-consuming and temperature-dependent classical mechanism of polymer interdiffusion via reptation in a melt state. Here, for the first time, we report a new mechanistic pathway for achieving solid-state polymer bonding by triggering rapid macromolecular acceleration through mechanical deformation. Large-scale molecular simulations reveal that active plastic deformation in glassy polymers, at temperatures well-below the bulk (and surface) glass transition temperatures, is sufficient to cause segmental translations of the polymer chains that lead to interfacial interpenetrations, and formation of new entanglements. The underlying mechanistic basis for this new type of bonding is identified as enhanced molecular-scale dilatations (or densifications) in conjunction with accelerated molecular mobility during plastic deformation. The reported mechanistic insights open promising avenues for designing new bonding technologies or material systems, and transformation of the existing ones to achieve quick and energetically less intensive bonding.

cond-mat.soft↗