This work is devoted to the study of existence results for a class of nonlinear conformable fractional pantograph differential equations subject to nonlocal initial conditions. By employing the conformable fractional derivative of order β∈(1,2), the considered problem is transformed into an equivalent integral equation. The Kuratowski measure of noncompactness combined with topological degree theory for condensing operators is then used to establish the existence and boundedness of solutions. An illustrative example is presented to highlight the applicability of the theoretical findings.
The global demand for compact and low power IoT devices is rapidly increasing, particularly in countries like India and those in South Asia. Low Power Wide Area Networks (LPWANs) equipped with LoRa antennas are well-suited to address this need. Most existing LoRa antennas are multiband microstrip designs with the operating bands usually limited to one of the LoRa bands AS923-1, EU868, IN865, and RU864, along with other sub-GHz ranges. In this paper, we present a compact, low-cost, reconfigurable Meandered Monopole antenna (MMA) designed to operate only in the LoRa IN865 and AS923-3 bands. To keep the antenna compact and economical, a meandered monopole structure has been employed with an RF PIN diode on an FR-4 substrate. Unlike existing designs, the proposed antenna is accurately tuned and is dedicated solely to the LoRa frequency band. The design was simulated using CST Microwave Studio (CST-MWS) and validated through prototype measurements. Furthermore, a unique lumped equivalent circuit model was developed using Keysight ADS. The proposed antenna has shown good pattern stability and achieves a gain of 2.07 dBi. With the diode in the active (ON) state, the antenna resonates at 866.2 MHz (IN865 LoRa Band) with an S11 of -17.22 dB and Bandwidth of 19 MHz. In the inactive (OFF) state of the diode, the antenna resonates at 916.5 MHz (AS923-3 LoRa Band) with an S11 of -15.24 dB and Bandwidth of 22 MHz. The results confirm that the proposed antenna provides reliable reconfigurability for LoRa applications in the specified bands.
We present a reproducible case study probing the adversarial robustness of ESM-2 (esm2 t6 8M UR50D), a representative protein language model, under substitution-based adversarial attacks, measuring pseudo-perplexity shift across eight benchmark protein sequences at mutation rates of 1%, 5%, and 10%. Our results show that random non-synonymous substitutions increase ESM-2’s mean perplexity by +9.9%, +11.9%, and +23.5% respectively, with individual sequences exhibiting shifts as high as +66.6%. We find that sequence length modulates robustness: longer, evolutionarily conserved sequences such as Ubiquitin show a clear dose-response to mutation rate, while shorter sequences saturate at low mutation budgets. Beyond model vulnerabilities, we analyze biosecurity risks associated with AI-generated proteins, situating our findings within existing governance frameworks including the Biological Weapons Convention, the NIH P3CO framework, and NSABB guidelines. We propose mitigation strategies including toxicity screening pipelines and access control policies, and identify adversarial training, Bayesian uncertainty estimation, and knowledge distillation as promising defense directions for future investigation. All code and data are publicly available at GitHub repository for ESM2 adversarial robustness.
The optimization of the actuation systems in the humanoid robotic arm is the focus of this research, which considers different factors including motor performance, selection of materials, and innovative mechanisms. By systematically testing a number of Brushless DC (BLDC) motors with different KV ratings and reduction ratios, it was concluded that the 5048 100KV motor with 30:1 cycloidal drive was optimal, with a high KV rating, high efficiency, low weight and low price. According to the voltage analysis, the 24V system doubled the torque, reduced heat generation and increased responsiveness over the 12V system. Comparisons of material properties between 3D-printed PLA+ and aluminum revealed that PLA+ could be used for lightweight prototype making and aluminum could be used for highly loaded parts due to high strength and high precision. The limitations that are faced by the conventional designs (high inertia, mechanical complexity, energy inefficiency) are overcome by proposing to move forward from the conventional design to a Low Inertia Manipulator with High Stiffness and Strength (LIMS). This is a tension amplified mechanism where the tension is amplified using cable driven mechanisms with high torque to weight ratios, low backlash and high compliance as compared to conventional BLDC based mechanisms. The results provide practical guidance in designing a lightweight and energy-efficient robotic arm and indicate that a hybrid approach for the prototyping to production process is necessary and LIMS should be used in the design of next generation humanoid manipulators.
An amorphous ribbon of composition Fe76.5-xNbxCu1Si13.5B9 (x = 1, 3, 5, and 7) was synthesized by the rapid solidification of chilling metallic liquids by melt spinning technique. The crystallization onset temperatures for the studied samples have been evaluated from Differential Scanning Calorimetry (DSC). X-ray diffraction pattern confirms the growth of the nano-crystalline Fe(Si) phase on the amorphous matrix. Moreover, the microstructure and grain size for all samples have been determined by field emission scanning electron microscopy (FESEM). It is observed that the crystallization phase and grain sizes increase due to heat treatment. However, the sizes of grains are reduced for the replacement of Fe3+ with a high amount of Nb5+. In addition, the hardness also increases along with the increase of Nb content and heat treatment. Finally, a brief study on crystalline phase kinetics and its controlling parameters for the Finemet® alloy system has been explored.
