Sound Interface Research Articles

Simultaneous enhancement of strength and ductility of Al matrix composites enabled by submicron-sized high-entropy alloy phases

Our study investigated the reinforcing effect of submicron-sized (100–500 nm) Al0.5CoCrCuFeNi high-entropy alloy particles (HEAps) on the tensile properties of Al matrix composites. The HEAps were refined to the submicron-sized level via a thermal plasma process to maximize reinforcing efficiency by increasing specific surface (i.e., interface) area. The Al/HEA composites were produced by hot rolling of mechanically milled Al/HEA composite powder. The microstructural analysis demonstrated that the HEAps were uniformly dispersed within the Al matrix by forming a sound interface without interdiffusion brittle intermetallic layers or any noticeable voids. Moreover, the addition of 2 vol% HEAps resulted in a simultaneous increase in both yield strength from 355 to 403 MPa and tensile elongation from 1.3 to 3.3%. As a result, the composite experienced a synergistic effect due to the combination of intrinsic strengthening to promote uniform plastic deformation and extrinsic strengthening to mitigate plastic instability and crack propagation.

Microstructural evolution and mechanical properties of aluminum-graphite composites processed via accumulative roll bonding

In the present work, the aluminum-graphite metal matrix composites were fabricated via accumulative roll bonding (ARB). The graphite powder particles of <50 μm were introduced into aluminum in three different weight percentages. The effect of graphite on the evolution of microstructure, interface formation, and mechanical properties was studied. The microstructural investigation revealed that the amount of graphite played a vital role. A better particle distribution was observed for 1.25 and 1.5 wt%. However, a further increase in the reinforcement to 2.2 wt% shows longer flaky graphite with comparatively sharing a larger interface area with the matrix aluminum. An FE-SEM/EDS (Field Emission-Scanning electron microscopy/Energy dispersive Spectroscopy) line mapping at the aluminum-graphite interface confirmed an intact sound interface with better adherence properties. The ultimate tensile strength of the composites drastically improved with an increasing number of ARB passes. The FE-SEM taken over the fractured surface of the composite revealed that the ARBed Al-1100 and the composites failed in ductile mode. It was observed that the graphite particle was the primary source of nucleation in the composites. The voids have nucleated at the particle-matrix interface, followed by their growth and coalescence.

Development of a Diffusion Bonding Route for Joining Oxide-Dispersion-Strengthened (ODS) Steels for Nuclear Applications

Oxide-dispersion-strengthened (ODS) steels are candidate materials for components in current and future nuclear power plants. One of the issues with using ODS steels is the difficulty of joining them without loss of mechanical performance. In this study, austenitic ODS 316L stainless steel was diffusion-bonded to Inconel 718 superalloy. Having optimized the bonding conditions, a number of samples were made at 1200 °C with a bonding time of 1 hour and pressure of 10 MPa. Preliminary mechanical and microstructural analyses indicated the formation of a sound joint interface, despite slight grain growth in the ODS 316L. A post-bonding thermo-mechanical treatment (TMT) was conducted to refine and restore the microstructure of the ODS 316L. Comparative TEM investigations of the parent ODS alloy and the bonded samples (with and without TMT) along with statistical analyses showed that the Y–Ti–O oxide size distribution remains unaffected by the bonding and complementary TMT cycles, indicating stability of such particles even at very high temperatures and suitability of the devised route for joining the ODS 316L steel.

Study on bimetallic composites interface of Al/SiCp-Al matrix composites prepared by liquid-liquid compound casting

Aimed at the preparation of bimetallic composites by using a liquid–liquid compound casting method with a sound interface, this study focused on the interface evolution with an increase in the pouring time interval. The results revealed that the melt mixing occurred when the pouring interval was 3 s. The transition zone appeared at the interface when the pouring interval was 10 s, and a good metallurgical bond was obtained. When the pouring interval was 20 s, a discontinuous oxide layer appeared at the interface. The oxide layer gap formed a channel for the transport of the SiC particles.

Effect of thermal condition on isothermal-pressing joined strength of silanized Al alloy/carbon fiber-reinforced polyamide-6

Carbon fiber-reinforced thermoplastics (CFRTPs) and lightweight metals are widely used in multi-material structures owing to their high strength and excellent corrosion resistance, thus stimulating research on various heat-assisted techniques to join them. Currently, the isothermal-pressing process has been developed to realize sound interface joining between CFRTP and Al alloy under relatively uniform thermal conditions. However, a quantitative investigation of the interaction between thermal conditions, chemistry reactions, and joining strength is still lacking. This current investigation analyzed chemical reaction state and resultant bonded strength of isothermal-pressing joined interface of silanized 5052 Al alloy and carbon fiber-reinforced polyamide-6 (CF/PA6) under various thermal conditions. X-ray photoelectron spectroscopy and Raman scattering analysis showed the increasing consumption of epoxy groups on silanized 5052 Al alloy side with the increase in joining temperature and residence time. This suggested higher temperatures and sufficient high-temperature duration times could efficiently promote the interface chemical reaction, increasing interface bonding strength. As the joining temperature or residence time increased, the fracture location gradually shifted from the silane coupling layer/re-solidified resin interface to the re-solidified resin close to interface, and even it directly passed through CF/PA6 along the thickness direction. Under the current adopted conditions, a critical high-temperature duration time of ∼6.0 s at least was recommended by optimizing the joining time to achieve high-strength joining between 5052 Al alloy and CF/PA6. The findings will guide optimizing the joining conditions in heat-assisted joining processes of Al/CFRTP hybrid structures.

Additive manufacturing of Ti-6Al-4V/V-interlayer/17-PH steel functionally graded material using angular and spheroidal V powders

The applications of V as an interlayer in functionally graded materials (FGMs) fail prematurely because of its angular shape. In this study, a radiofrequency thermal plasma process was employed to change the shape of V powder from angular to spheroidal. The angular and spheroidal V powders were then used to fabricate two FGMs, namely, Ti-6Al-4V/angular V/17-PH and Ti-6Al-4V/spherical V/17-PH. Unlike the angular V powder, the spherical V powder created a sound joint interface with a uniform layer and no cracks or delamination. The spheroidized V interlayer was thicker than the angular V interlayer. Unlike the spheroidized V interlayer, the angular V interface exhibited microcracks surrounded by σ phases. Moreover, Ti-6Al-4V/spherical V/17-PH exhibited superior mechanical properties. The high flowability associated with the fine spherical powders of Ti-6Al-4V/spherical V/17-PH significantly enhanced the efficiency of additive manufacturing and improved the microstructure and mechanical properties of the deposited joint.

Industrial Techno and SID Sound Design in the Commodore 64 GameSlipstream

Slipstream is a rail shooter developed by the group Bauknecht. The soundtrack, composed by Ronny Engmann, accentuates the game’s futuristic space setting and emphasis on speed by invoking the electronic dance music style of industrial techno, which combines the taut grooves of minimal techno with the abrasive sonics of early industrial music to make for an intensification of the sound that made the club scenes of Detroit and Berlin famous. Despite the Commodore 64 being a supposedly obsolete 8-bit platform that had its manufacture stopped decades ago, contemporary composers like Engmann are compelled to use the machine for its SID (Sound Interface Device) chip, which stands apart from the sound chips of other 8-bit home computers and consoles due to its variety of waveform types, filtering capabilities, ring modulation, and oscillator sync effects. The skills that Engmann developed while exploring the affordances of this versatile chip enabled him to compose a video game soundtrack that is informed by his engagement with the Berlin techno scene from the early 1990s onward. Drawing from ethnographic interviews with Engmann and Slipstream’s programmer Stefan Mader, this article demonstrates how techno’s pivotal theme of synergistic existence of humanity with technology resonates with an ecstatic feeling of forward propulsion that characterizes Slipstream. Focusing on the musical dimension of timbre and addressing the practical issues of modern cross-platform development through an analysis of Engmann’s project files for the Commodore 64 music tool GoatTracker, this article shows that Slipstream’s soundtrack is exemplary in effectively harnessing electronic dance music as video game music.

A Novel Machine Learning Based Two-Way Communication System for Deaf and Mute

Deaf and mute people are an integral part of society, and it is particularly important to provide them with a platform to be able to communicate without the need for any training or learning. These people rely on sign language, but for effective communication, it is expected that others can understand sign language. Learning sign language is a challenge for those with no impairment. Another challenge is to have a system in which hand gestures of different languages are supported. In this manuscript, a system is presented that provides communication between deaf and mute (DnM) and non-deaf and mute (NDnM). The hand gestures of DnM people are acquired and processed using deep learning, and multiple language support is achieved using supervised machine learning. The NDnM people are provided with an audio interface where the hand gestures are converted into speech and generated through the sound card interface of the computer. Speech from NDnM people is acquired using microphone input and converted into text. The system is easy to use and low cost. The system is modular and can be enhanced by adding data to support more languages in the future. A supervised machine learning dataset is defined and created that provides automated multi-language communication between the DnM and NDnM people. It is expected that this system will support DnM people in communicating effectively with others and restoring a feeling of normalcy in their daily lives. The hand gesture detection accuracy of the system is more than 90% for most, while for certain scenarios, this is between 80% and 90% due to variations in hand gestures between DnM people. The system is validated and evaluated using a series of experiments.

Microstructure and wear resistance of AlCoCrFeNi-WC/TiC composite coating by laser cladding

AlCoCrFeNi has excellent mechanical properties, however, its hardness and wear resistance are insufficient for engineering applications. In order to improve the wear resistance of AlCoCrFeNi coating, WC and in-situ TiC particles were used in this work. Subsequently, the microstructure, hardness, and wear resistance were studied in detail. The results showed that the in-situ TiC particles were uniformly distributed in the whole coating, ameliorating the uneven distribution of WC particles. A sound interface was formed between the particles and the coating matrix, proving the composite coating with excellent performance in wear resistance. The phase constituents of the coating matrix were the BCC and B2 phases. And BCC phase occurred lattice distortion due to the dissolution of W atoms, resulting in the solid solution strengthening of coating matrix. Furthermore, with the increase of WC content, a needle W-rich BCC phase appeared in the coating matrix. Finally, the hardness of AlCoCrFeNi-WC/TiC coatings increased from 516.4 HV 0.3 to 808.7 HV 0.3 , and the wear resistance was increased by 14 times. The improvement in hardness can be attributed to the WC particles, in-situ TiC particles, and solid solution strengthening. We prepared the AlCoCrFeNi-WC/TiC coating by laser cladding. The hardness and wear resistance are improved significantly by the WC particles, in-situ TiC particles, and solid solution strengthening. • The AlCoCrFeNi-WC/TiC coatings are reinforced by the WC particles, in-situ TiC particles, and solid-solution strengthening. • The in-situ TiC particles were uniformly distributed in the whole coatings, which ameliorates the uneven distribution of the WC particles. • The W element enhances the lattice distortion of the BCC phase, and the coating matrix is strengthened by the solid-solution strengthening. • The average hardness is increased by 292.3 HV 0.3 , and the wear resistance is increased by 14 times.

Cultural relationship between rural soundscape and space in Hmong villages in Guizhou

The Hmong is one of the oldest ethnic groups in south-western China, and sound plays an important role in their culture. According to the general classification of landscape science, the rural soundscape of Hmong villages is divided into three types: a point soundscape dominated by a single sound source, a line soundscape with a typical Hmong rural village alley space as the sound field interface, and an area soundscape with the Bronze-drum Square, the only open public space of Hmong nationality, as the field. Combined with a sound collection and field test during field investigation, we obtained the characteristics of various rural soundscapes and evaluated the acoustic environment. The results showed that the “point” soundscape of medium- and low-frequency powder shotgun and wooden drum sounds in the unclosed Hmong villages exceed the transmission distance and sound durability. The “line” soundscape utilizes the turning point and envelope of different spaces to increase the acoustic reflection surface and create reverberation, increasing the propagation time and distance of the sound, and emphasizing the directivity of the sound through a long and narrow space. The “surface” soundscape includes the richest medium- and high-frequency-based human voice and music sounds and medium- and low-frequency musical instrument sounds, among others. The values of T30, EDT, and C80 in the sound field, all changed significantly because of the lack of acoustic reflection from the ceiling, through the top opening. Finally, the study reveals the cultural association between rural soundscape and space, which is reflected in the Hmong's “defensive” function and “group” culture. Thus, the Bronze-drum Square sound field does not meet the requirements of the current specification of cultural interpretation, and it is in the participatory Hmong performance mode, centered on drum club group structure.

PF-Representation of Tense Feature on DPs: Morphosyntax of the φ-Agreeing T-Marker Tau

This research revises, develops and offers empirical evidence to two assumptions discussed in Pesetsky &amp; Torrego’s (2007) theory which claims that tense feature [T] is associated with and expressed on DPs in syntax. Investigating the syntax of a T-marker tau, used in Najdi Arabic, in contexts where tau interacts with DPs in the spine of the clause, empirical evidence is provided that [T] assumed to be associated with DPs is generated in syntax and spelled out at PF. This takes place by the minimalist strategy where a clitic φ-agreeing with the relevant DP is spelled out on tau.[1]This clitic is a PF device indicating that a DP is marked with Tense information RECENT. This clitic is morphological realisation of φ-content on tau that is processed in syntax in turn of tau’s valuation to [T] on a DP. Mapping syntax-morphosyntax to LF, Agree (Chomsky 2001) is established between tau and a DP in which i-[T] on tau values u-[T] on the DP on the condition that i-[φ] on the DP value u-[φ] on tau. Furthermore, this analysis, contrary to Pesetsky &amp; Torrego (2007), claims that [φ]-features on T° are crucial in valuing [T] feature on DP.[2][3][1] T-marker = Tense marker.[2] We represent the notion of feature using the convention ‘square brackets’ with the feature label. So, [T] means Tense feature and [φ] means [φ]-features.[3] LF = Logical form interface (Thought interface). PF = Phonological form interface (Sound interface).

Torsional behaviour of glass-joined, laser-processed Crofer 22 APU interconnect: Unravelling the effect of surface roughness on the shear strength

Glass-to-metal interfaces play a crucial role in the robustness and the mechanical integrity of solid oxide cells, and it is well known that a sound interface improves the mechanical reliability of the whole stack. The present work focuses on the torsional behaviour of hourglass-shaped Crofer 22 APU stainless steel joined by a glass sealant specifically designed for this application.Specific focus was given to the Crofer surface modification by laser processing, namely, the laser fluence was varied to find suitable roughness parameters; a laser fluence of 14.1 J cm−2, leading to a Crofer surface roughness of about 4.6 μm, was selected as the optimal Crofer surface processing before the joining process.The torsional shear strength of glass-joined as-received Crofer was measured as 24 ± 7 MPa with mainly adhesive fracture mode, with failure jumping from one interface to the other, while the laser-processed Crofer gave 32 ± 5 MPa with cohesive failure. The approximate 30% increase of torsional shear strength is due to the mechanical interlocking effect given by glass infiltration inside the laser-induced protrusions on Crofer as evidenced by SEM/EDS on cross-sections and fracture surfaces after torsion tests.

Eğitsel SDR Tekniklerine Dayalı FPGA Tabanlı FM Radyo Verici Tasarım ve Uygulaması

The basic purpose of Software Defined Radio (SDR) systems is to use a digital signal processor to numerically handle radio signals. The use of a processor like a Field Programmable Gate Array (FPGA) to perform tasks like modulation, demodulation, signal creation, and line coding on these systems dramatically decreases the demand for analog circuit-based hardware. FPGAs are digital integrated circuits with a wide range of applications which are made up of links between programmable logic blocks. It's aimed at assisting the creator realize the logic functions that the designer needs. In consequence, the user may change the function of each logic block. VHSIC Hardware Description Language (VHDL) is commonly used in FPGA programming. In this study, VHDL code was created, and a FM transmitter was implemented on a FPGA board (CMOD A7) in this research. The sound card interface on the PC used to send and receive the signals while suitable ADC and DAC cards are used on the FPGA side for the same purpose. Audacity program was used to playback the sample wav files while HDSDR SDR program was used to monitor and record the signals in wav file format. Finally, using the MATLAB code, the recorded transmitter signal was demodulated offline, and the output was stored to the hard drive. The demodulated signal obtained is identical to the initial modulation signal, indicating that the modulation was correctly executed. As a result, a perfect foundation for the development and training of SDR systems using FPGA has been established.

Zirconia-high entropy alloys joints for biomedical applications: The role of Ag-based fillers on interfacial reactivity

Metal-ceramic joints represent an important choice for biomedical devices, in orthopaedic field or as micro-stimulators. ZrO 2 -Ag-HEA joint is here proposed to replace the currently used Ti6Al4V by new Ti-based refractory HEAs. To evaluate the system reactivity, wettability of ZrO 2 by different Ag-based alloys at 1000 °C and their interfacial layers were studied, for the first time. Interpretation and discussion of systems reactivity were supported by thermodynamic calculations, according to the CALPHAD approach and the ad-hoc Ag-Ti-Zr-O thermodynamic database, implemented in this work. A good wettability was reached at 1000 °C adding Ti to Ag: Ag-4Ti and Ag-8Ti reached contact angles of 81–85°. Ag-4Ti-2Zr showed the best wettability (77°) and the most complex interfacial microstructure. A continuous hcp (Ti,O), ~ 20 µm thick, promoted the wettability of Ag-4Ti and Ag-8Ti. In both cases, AgTi was the only intermetallic compound found in the bulk. Ag-4Ti-2Zr formed a thicker interfacial layer of hcp-(Ti,Zr,O) + bcc-(Ti,Zr) + a less compact Ag(Ti,Zr) 2 layer. Here, a low amount of Ag(Ti,Zr) and Ag(Ti,Zr) 2 was found in the Ag matrix. Since Ag resulted a promising filler to braze Ti-rich substrates to ZrO 2 at 1000 °C, preliminary HEA-Ag-ZrO 2 joints were characterized. A sound and defects-free interface was observed, with a first layer, mainly formed by Ag, Ti and Zr (HV ~ 600), and a Ag-based interface (HV ~ 250), extending until the HEA. Further works envisage mechanical and electrochemical evaluations of the system to pave the way for the production of novel HEA-Ag-ZrO 2 joints to be used in biomedical applications. • Ti addition to Ag promoted ZrO 2 wettability at 1000 °C forming hcp-(Ti,O) at the interface. • Ag-4Ti-2Zr tested on ZrO 2 at 1000 °C showed the best wettability (ϑ<80°). • An ad-hoc Ag-O-Ti-Zr database was assembled and used to support reactivity discussion. • Ag-4Ti-2Zr showed an hcp-(Ti,O)+bcc-(Ti,Zr)+Ag(Ti,Zr) 2 interfacial layer formed at 1000 °C. • Ti 1.5 ZrTa 0.5 Hf 0.5 Nb 0.5 HEA was successfully brazed to ZrO 2 by using a Ag filler at 1000 °C.

Tom Erbe Interviewed by Theodore Gordon

In this interview, Tom Erbe reflects on his three decades as a developer of computer music software and hardware, both freeware and commercial. Tom met with Theodore Gordon on 8 December 2021 and discussed the beginnings of SoundHack and its roots in experimental music studio practice and hacker culture, ideas behind the design of sound processor interface and the shift from experimental software development to Eurorack modular hardware design.

Joining of Ti6Al4V to Al2O3 Using Nanomultilayers.

Diffusion bonding of Ti6Al4V to Al2O3 using Ni/Ti reactive nanomultilayers as interlayer material was investigated. For this purpose, Ni/Ti multilayer thin films with 12, 25, and 60 nm modulation periods (bilayer thickness) were deposited by d.c. magnetron sputtering onto the base materials’ surface. The joints were processed at 750 and 800 °C with a dwell time of 60 min and under a pressure of 5 MPa. Microstructural characterization of the interfaces was conducted by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). The mechanical characterization of the joints was performed by nanoindentation, and hardness and reduced Young’s modulus distribution maps were obtained across the interfaces. The joints processed at 800 °C using the three modulation periods were successful, showing the feasibility of using these nanolayered films to improve the diffusion bonding of dissimilar materials. Using modulation periods of 25 and 60 nm, it was also possible to reduce the bonding temperature to 750 °C and obtain a sound interface. The interfaces are mainly composed of NiTi and NiTi2 phases. The nanoindentation experiments revealed that the hardness and reduced Young’s modulus at the interfaces reflect the observed microstructure.

Interfacial Microstructure Analysis of AZ31 Magnesium Alloy during Plastic Deformation Bonding

In this study, a plastic deformation process consisting of hot compression at 350 °C and heat treatment at 400 °C was performed to bond AZ31 magnesium alloy. Microstructural evolution around the bonding interface was systematically characterized to investigate the bonding process and clarify the bonding mechanism. When the plastic deformation strain reached 0.6, the bonding zone was full of fine dynamic recrystallized grains and the initial interface was eliminated. The post-heating treatments were conducted to achieve a sound interface bonding. The tensile tests and the corresponding fracture morphologies analysis indicated that the optimum holding time of heat treatment was 8 h. The interfacial bonding strength of the specimens holding for 8 h reached 164.7 MPa, an enhancement of about 9% compared with that of the specimens holding for 1 h. The microstructure analysis indicated that the bonding quality was affected by migration of the interfacial grain boundary (GB), the development of recrystallized grains and the evolution of interfacial oxides around the bonding area.

RetQSS: A novel methodology for efficient modeling and simulation of particle systems in reticulated geometries

This work presents retQSS, a novel methodology for efficient modeling and simulation of particle systems in reticulated meshed geometries. On the simulation side, retQSS profits from the discrete-event nature of Quantized State System (QSS) methods, which enable efficient particle tracking algorithms that are agnostic of the application domain. On the modeling side, retQSS relies on the standardized Modelica modeling language, yielding compact and elegant specifications of hybrid (continuous/discrete) dynamic systems. Combined together, these features offer a sound, general-purpose framework for modeling and simulation of particle systems. We show how the state-events that arise when particles interact with a reticulated mesh are seamlessly translated into easily tractable time-events. The latter can substantially improve simulation performance in scenarios where discontinuities dominate the computational demand. We showcase the flexibility of our approach by addressing four case studies arising from different application domains. Performance studies revealed that retQSS can perform similarly to, and even outperform, well-known domain-specific particle simulation toolkits while offering a clear and sound accuracy control interface.

Numerical prediction of maldistribution in a series of T-junctions

This work assesses the possibility/feasibility of utilizing the CFD to predict water-air separation in a mini-manifold at ambient conditions. The manifold consists of a header with three reduced T-junctions. A combination of the manifold size and the operating parameters yields a computationally demanding surface tension dominant flow. A computational model of separation is based on the interface tracking technique and the FVM framework. The results are validated against the experiment. Findings show that the separation can be successfully predicted, even under such conditions. Analysis of computational cost revealed that the long computational time is the only limiting factor for regular CFD use in such applications. The paper's novelty is in the successful prediction of phase separation. Such an approach requires flow pattern prediction capabilities in the straight parts of the manifold and physically sound interface split prediction at the T-junctions that have not been explored previously in such a way.

Design of battery pack & controller for combined auto driven mini-harvester

The mechanized farming can promisingly increase the profitability and prevent the dependency of farmers on foreign labours. The design and implementation of Battery pack and controller for specially designed combined auto-driven mini harvester is presented in this paper. The mechanical load estimation and its mapping with electrical drives are formulated. The interfacing of electrical drives with remote operation is achieved by Electronic Arduino system. The relay control system is designed with individual drive system. The sketches are mapped with the functionality of drives. The drive selection is a dependant function of mechanical load requirement. The mechanical load estimation is done with actual mechanical failure consideration and design approach. The pin-out connections for all the ports are done on the basis of logical sketch command. The open source Arduino software is used to run the sketches. The sketch written for all the drives is compiled and demo prototype machine is tested for functioning. The run trail is successful and can conclude that the Arduino mega gives the sound interface with 8 channel relay. The computation and measurement results of power requirements for the controller and drive are within the limiting conditions.