Ultra‐Fast One‐Step Fabrication of Cu2Se Thermoelectric Legs With Ni–Al Electrodes by Plasma‐Activated Reactive Sintering Technique

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/133615/1/adem201500548-sup-0001-SupFigs-S1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133615/2/adem201500548.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133615/3/adem201500548_am.pd

Effects of magnetic field on thermo-hydraulic performance of Fe3O4-water nanofluids in a corrugated tube

© 2018 Elsevier Ltd An experimental system is established to investigate the thermo-hydraulic performance of Fe3O4-water nanofluids in a corrugated tube under various magnetic fields. The influences of magnetic induction intensities (B = 0 G, 100 G, 200 G, 300 G), nanoparticle mass fractions (ω = 0.0%, 0.1%, 0.3%, 0.5%), electromagnet arrangement modes (one-side electromagnet and two-side staggered electromagnet), kinds of tubes (smooth tube and corrugated tube), Reynolds numbers (Re = 800–12,000) on flow and heat transfer characteristics are discussed. It is obtained that the augmentation of heat transfer is more sensitive to high nanoparticle mass fraction, high magnetic induction intensity, two-side staggered electromagnet and corrugated tube. A Comprehensive evaluation index is applied to estimate the thermo-hydraulic performance. It can be discovered that the comprehensive evaluation index increases with the increasing Reynolds number at first and then decreases, and the rough surface of corrugated tube delays the appearance of critical Reynolds number

Enrollment-stage Backdoor Attacks on Speaker Recognition Systems via Adversarial Ultrasound

Automatic Speaker Recognition Systems (SRSs) have been widely used in voice applications for personal identification and access control. A typical SRS consists of three stages, i.e., training, enrollment, and recognition. Previous work has revealed that SRSs can be bypassed by backdoor attacks at the training stage or by adversarial example attacks at the recognition stage. In this paper, we propose TUNER, a new type of backdoor attack against the enrollment stage of SRS via adversarial ultrasound modulation, which is inaudible, synchronization-free, content-independent, and black-box. Our key idea is to first inject the backdoor into the SRS with modulated ultrasound when a legitimate user initiates the enrollment, and afterward, the polluted SRS will grant access to both the legitimate user and the adversary with high confidence. Our attack faces a major challenge of unpredictable user articulation at the enrollment stage. To overcome this challenge, we generate the ultrasonic backdoor by augmenting the optimization process with random speech content, vocalizing time, and volume of the user. Furthermore, to achieve real-world robustness, we improve the ultrasonic signal over traditional methods using sparse frequency points, pre-compensation, and single-sideband (SSB) modulation. We extensively evaluate TUNER on two common datasets and seven representative SRS models. Results show that our attack can successfully bypass speaker recognition systems while remaining robust to various speakers, speech content, e

Inaudible Adversarial Perturbation: Manipulating the Recognition of User Speech in Real Time

Automatic speech recognition (ASR) systems have been shown to be vulnerable to adversarial examples (AEs). Recent success all assumes that users will not notice or disrupt the attack process despite the existence of music/noise-like sounds and spontaneous responses from voice assistants. Nonetheless, in practical user-present scenarios, user awareness may nullify existing attack attempts that launch unexpected sounds or ASR usage. In this paper, we seek to bridge the gap in existing research and extend the attack to user-present scenarios. We propose VRIFLE, an inaudible adversarial perturbation (IAP) attack via ultrasound delivery that can manipulate ASRs as a user speaks. The inherent differences between audible sounds and ultrasounds make IAP delivery face unprecedented challenges such as distortion, noise, and instability. In this regard, we design a novel ultrasonic transformation model to enhance the crafted perturbation to be physically effective and even survive long-distance delivery. We further enable VRIFLE's robustness by adopting a series of augmentation on user and real-world variations during the generation process. In this way, VRIFLE features an effective real-time manipulation of the ASR output from different distances and under any speech of users, with an alter-and-mute strategy that suppresses the impact of user disruption. Our extensive experiments in both digital and physical worlds verify VRIFLE's effectiveness under various configurations, robustness against six kinds of defenses, and universality in a targeted manner. We also show that VRIFLE can be delivered with a portable attack device and even everyday-life loudspeakers.Comment: Accepted by NDSS Symposium 202

Optimisation in the Logistics and Management of Supply Chains in Production by Textile Enterprises

This article is devoted to questions regarding the analysis of the implementation of logistics and supply chain management conditions in textile production. Based on delivery optimisation, the authors offer a model of multimodal transportation of textile products produced in Uzbekistan. The importance of optimising the supply chain of the logistics business processes in order to decrease costs is demonstrated in this article. A mathematical model of optimisation for placement textile enterprises to stimulate the reduction of supply chain costs is recommended. However, this research would be beneficial for the textile and fashion industries. The approach might be further extended to other similar industries

The Role of Zn in Chalcopyrite CuFeS2: Enhanced Thermoelectric Properties of Cu1–xZnxFeS2 with In Situ Nanoprecipitates

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136267/1/aenm201601299_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136267/2/aenm201601299.pd

Association of periodontitis and tooth loss with extent of coronary atherosclerosis in patients with type 2 diabetes mellitus

AimThe objective was to investigate the association of periodontitis and tooth loss with extent of diabetic coronary atherosclerosis.Materials and methods272 patients who were hospitalized at Shanghai East hospital and underwent a coronary artery calcium (CAC) CT scan were enrolled in this study. Individuals were grouped based on their CAC scores into a normal-to-mild coronary atherosclerosis (AS) group (0 ≤ score ≤ 100, n=184) and a moderate-to-severe group (score≥101, n=88). Periodontitis parameters and number of missing teeth were evaluated for every patient. The severity of periodontitis was categorized as mild, moderate, or severe. The taxonomic composition of the microbiota was determined using full-length 16S ribosomal RNA gene sequencing. Salivary inflammatory factors were tested by ELISA.ResultsClinical attachment loss (CAL) (P =0.05) and the number of teeth lost (P = 0.016) were significantly higher in the moderate-to-severe coronary AS group, with these differences being more obvious in younger patients and patients with short-duration diabetes. Multivariate logistic regression analysis revealed that CAL (OR = 1.231, 95% CI = 1.066–1.214, P = 0.047) and having 10–19 missing teeth (OR = 1.604, 95% CI = 1.393–6.555, P = 0.05) were strongly associated with the presence of moderate-to-severe coronary AS. Salivary IL-6 and TNF-α levels, as well as levels of Porphyromonas gingivalis and Neisseria mucosa, were significantly elevated in the moderate-to-severe coronary AS group.ConclusionIt was found that both tooth loss and CAL were related to the extent of diabetic coronary AS. Saliva inflammatory factors and oral bacteremia may be new biomarkers for moderate-to-severe coronary AS

Thick MgB2 film with (101) oriented micro-crystals

Very thick, ~ 40 $\mu$m, clean, and highly textured MgB2 film was effectively grown on an Al2O3 substrate. The fabrication technique is by the hybrid physical-chemical vapor deposition (HPCVD) using B2H6 gas and Mg ingot as the sources. The X-ray diffraction (XRD) analysis shows a highly (101)-oriented MgB2 crystal structure without any impurity detected. There is no signal from the substrate in the XRD spectrum, indicating that the film thickness exceeds the X-ray penetration length. Scanning electron microscopy (SEM) reveals that the film is composed of highly-packed MgB2 micro-crystals with a uniform size distribution of about 2 $\mu$m in diameter and 0.2 $\mu$m in thickness. According to the compositional analysis of energy-dispersive X-ray spectroscopy (EDX), no oxygen, hence no MgO, exists in the textured film, consistent with the XRD result. Also, the transport properties are similar to those of a single crystal, indicating a clean film of good crystallite. The zero field transition temperatures are determined as TC(onset) = 39.2 K and TC(zero) = 38.4 K, giving a sharp transition typical of a clean sample. The residual resistivity ratio (RRR) is determined as 6.4 and the magnetoreisitance (MR) is about 28 % at 40 K under the applied field of 9 T, which are similar to those of a single crystal. The zero temperature upper critical field, HC2(0), is extrapolated as 19 T from the TC(onset) at applied field up to 9 T.Comment: 10 pages, 4 figure