Online Speech Enhancement by Retraining of LSTM Using SURE Loss and Policy Iteration

Neural Processing Letters - Speech enhancement is required for improving the quality and intelligibility in various applications such as recognition, hearing aids and other personal assistant...     

Infrastructure Challenges Caused by Industrial Transformation to Achieve Greenhouse Gas Neutrality. Ammonia Production in the Antwerp-Rotterdam-Rhine-Ruhr Area

Several pathways for potentially greenhouse gas neutral production of ammonia have been investigated compared to today's conventional ammonia production at chemical sites in Antwerp, Dormagen, and Geleen. These pathways include on-site water electrolysis using grid electricity, off-site production via water electrolysis using renewable electricity and supply of green hydrogen to the site, pyrolysis of natural gas and conventional ammonia production coupled with CO₂-capture on-site and transport to a storage site. All pathways effectively eliminate scope 1 emissions present in conventional production but continue to emit scope 2 emissions from grid electricity consumption. Eventually, a coordinated industry-wide and cross-industry effort is needed to address the transformational changes and develop the common cross-border infrastructures.     

High-gain W-band-printed antenna on flexible substrate

This article demonstrates a novel type of series-fed planar antenna array for a W-band (70 GHz) application. The proposed architecture is a 5-element antenna array with 10 numbers of gap-coupled parasitic patches in microstrip configuration over a thin, flexible and bio-compatible substrate named LCP (liquid crystal polymer). A detailed design methodology with all fabrication constraints has been elaborated on here. Full wave analysis of the whole structure has been carried out in the FEM-based 3D electromagnetic (EM) solver ANSYS HFSS Suite V.19.2. Parametric simulations were studied to achieve the optimized values of all design parameters. Further, an empirical electrical equivalent circuit model is proposed for the antenna array, and it was validated with the simulation results obtained from the FEM solver. Two prototypes have been fabricated, and measurements were carried out to fetch all the designed antenna parameters. The proto version of the antenna offers peak directive gain of about 19 dBi with better than 22 dB of return loss and 80% radiation efficiency for the frequency range of 67–85 GHz. Experimental and simulated results closely match each other. Small deviations are attributed to practical imperfections incurred by fabrication tolerances, measurement inaccuracies, testing, assembly-related issues and so forth. Finally, the current research work is compared with the recently reported literature.     

Bond graph modeling of a railway truck on curved track

Rail vehicles become unstable beyond a critical speed because of speed dependant creep forces at the rail-wheel contact surface. There is a constant demand for improved rail vehicle model for design of high-speed vehicles, and track. Works available in the literature are based on models of trucks with various simplifying assumptions such as reduced degree of freedom, small displacements and without kinematic nonlinearities and inclination of the contact surface. In this paper an integrated bond graph model of a truck is developed for the first time without the aforementioned assumptions. It is found that truck dynamical behavior is significantly different from those found in the literature in some cases.     

Self-assembly of neutral dinuclear and trinuclear zinc-benzoate complexes

A structurally important self-assembly of dinuclear and trinuclear zinc-benzoate complexes having formula [Zn₃(μ-OBz)₆(py)₂] · [Zn₂(OBz)₄(py)₂] (A) (where OBz is benzoate and py is pyridine ligand) is reported. The dinuclear and trinuclear complexes present in the crystal lattice of the self-assembly are held together by weak C–Hπ and C–HO interactions.     

Taguchi's Method Analysis of an FMS Under Review-Period-Based Operational Controls: Identification of Control Periodicity

Flexibility of flexible manufacturing systems (FMSs) has been considered as an effective tool to compete in the present manufacturing environment. Enormous research efforts have been made to harness the benefits of flexibility through superior control strategies. While modeling flexibility and control strategies, researchers have mostly assumed an information system that can provide real-time control. Literature qualitatively reports that the real-time control can be highly capital intensive and difficult to achieve. This paper focuses on FMS operating under review-period (RP)-based control and presents a combined study of routing flexibility (RF), control strategies, and information system under Taguchi's method using simulation. RP-based control for FMS has been compared with real-time control. This paper contributes an approach for the decision maker to study the performance of an FMS operating under RP control and to identify the periodicity (time interval) of RP that will not deteriorate its performance in comparison to real-time control. It also helps the decision maker to reach a tradeoff between RP-based control and real-time control. The results show that RP-based control can be effectively implemented on an FMS having lower RF level. RP-based control can outperform real-time control with a superior control strategy and smaller RP size. The results under Taguchi's method suggest that the RF and control strategy should have maximum relative percentage contributions in FMS performance, whereas contribution of the RP (information system) should be minimum. Increasing the relative percentage contribution of the information system may deteriorate the performance of FMS. The information system is needed as a catalyst to facilitate the contributions of other factors in improving the FMS performance and not its own contribution     

Microstructure characterization of in situ synthesized porous Si<Subscript>3</Subscript>N<Subscript>4</Subscript>–Si<Subscript>2</Subscript>N<Subscript>2</Subscript>O composites using feldspar additive

Porous Si₃N₄–Si₂N₂O bodies fabricated by multi-pass extrusion process were investigated depending on the feldspar addition content (4–8 wt% Si) in the raw silicon powder. The diameter of the continuous pores was about 250 μm. The polycrystalline Si₂N₂O fibers observed in the continuous pores as well as in the matrix regions of the nitrided bodies can increase the filtration efficiency. In the 4 wt% feldspar addition, the diameter of the Si₂N₂O fibers in the continuous pores of the nitrided bodies was about 90–150 nm. A few number of rope typed Si₂N₂O fibers (∼4 μm) was found in the case of 8 wt% feldspar addition. However, in the 8 wt% feldspar addition, the matrix showed highly porous structure composed of large number of the Si₂N₂O fibers (∼60 nm). The relative densities of the Si₃N₄–Si₂N₂O bodies with 4 wt% and 8 wt% feldspar additions were about 65% and 61%, respectively.     

Effect of alloying with zinc on SFE of aluminium by study of lattice imperfections in cold worked Al-Zn alloys

A detailed X-ray Fourier line shape analysis has been performed on three compositions of Al-Zn alloys viz. Al-3.55 wt% Zn, Al-14.7 wt% Zn and Al-19.3 wt% Zn infcc phase. It has been found that deformation stacking faults, both intrinsic ά and extrinsic α are absent in the cold worked state and twin fault β is found to be slightly present in the deformed lattice of the two initial compositions of the alloys. Similar to the effect of solute germanium and copper, respectively in Al-Ge and Al-Cu systems, hexagonal zinc also fails to impart faulting infcc Al-Zn system. This corroborates the fact that aluminium has high stacking fault energy.     

Study of electrically small printed chakra (wheel) antenna

A novel printed antenna configuration in the form of a chakra (wheel) is presented. The antenna has many design parameters, such as axle radius, rim radius, and shaft location, and exhibits a very low design frequency which is five times smaller than that of a regular circular microstrip patch antenna of the same size