Sensors, Vol. 19, Pages 3991: Wideband and Wide Beam Polyvinylidene Difluoride (PVDF) Acoustic Transducer for Broadband Underwater Communications

Sensors, Vol. 19, Pages 3991: Wideband and Wide Beam Polyvinylidene Difluoride (PVDF) Acoustic Transducer for Broadband Underwater Communications Sensors doi: 10.3390/s19183991 Authors: Marcos S. Martins Carlos L. Faria Tiago Matos Luís M. Goncalves José Cabral António Silva Sérgio M. Jesus The advances in wireless communications are still very limited when intended to be used on Underwater Communication Systems mainly due to the adverse proprieties of the submarine channel to the acoustic and radio frequency (RF) waves propagation. This work describes the development and characterization of a polyvinylidene difluoride ultrasound transducer to be used as an emitter in underwater wireless communications. The transducer has a beam up to 10° × 70° degrees and a usable frequency band up to 1 MHz. The transducer was designed using Finite Elements Methods and compared with real measurements. Pool trials show a transmitting voltage response (TVR) of approximately 150 dB re µPa/V@1 m from 750 kHz to 1 MHz. Sea trials were carried in Ria Formosa, Faro (Portugal) over a 15 m source—receiver communication link. All the signals were successfully detected by cross-correlation using 10 chirp signals between 10 to 900 kHz.
Source: Sensors - Category: Biotechnology Authors: Tags: Article Source Type: research

Related Links:

Authors: Baldi D, Colombo J, Robiony M, Menini M, Bisagni E, Pera P Abstract BACKGROUND: The purpose of this study was to analyze pulpal temperature increase generated by prosthodontic margin repositioning and finishing with ultrasonic and rotating instruments. The temperature changes recorded were also correlated with the residual dentin thickness. METHODS: A sample of 32 human extracted molars was selected. The teeth were endodontically treated and prepared with prosthetic round chamfer preparation. Then, they were inserted in plaster cubes up to the cement-enamel junction, leaving the apical portion pervious...
Source: Minerva Stomatologica - Category: Dentistry Tags: Minerva Stomatol Source Type: research
Conclusions: Surgical treatment of anomalous placement of the placenta in third-level hospitals can prevent adverse perinatal outcomes. Expectant management is possible in selected patients. PMID: 31631190 [PubMed - in process]
Source: Cirugia y Cirujanos - Category: Surgery Authors: Tags: Cir Cir Source Type: research
ConclusionThe results failed to show a statistical difference between DHRT- and manikin-trained residents. This study validates the transfer of skills from training on the DHRT system to performing US-IJCVC in clinical environments.
Source: The American Journal of Surgery - Category: Surgery Source Type: research
We report the case of a 44-year-old patient with low back pain and radiculopathy. Radiographs revealed lytic spondylolisthesis in L5. Magnetic resonance imaging showed hypointense signal on T1 and a heterogeneous signal on T2 located in the L4-L5 interspinous space and in the left facet joint that invades left neuroforamen. The left knee ultrasound showed “double contour” of the medial femoral condyle. Decompressive laminectomy with arthrodesis at the level of L5-S1 was performed. The histological examination revealed amorphous material with a foreign body giant cell reaction.ResumenLos depósitos de tofo...
Source: Reumatologia Clinica - Category: Rheumatology Source Type: research
Condition:   Breast Cancer Intervention:   Sponsor:   Sunnybrook Health Sciences Centre Recruiting
Source: - Category: Research Source Type: clinical trials
Condition:   Pain, Chest Interventions:   Device: ultrasound;   Drug: Bupivacaine Hydrochloride 5 MG/ML Sponsor:   Fayoum University Hospital Not yet recruiting
Source: - Category: Research Source Type: clinical trials
Condition:   Carotid Artery, Internal Intervention:   Diagnostic Test: Ultrasound assessment Sponsor:   Seoul National University Hospital Not yet recruiting
Source: - Category: Research Source Type: clinical trials
Publication date: Available online 21 October 2019Source: Food ChemistryAuthor(s): Ling Yan, Lei Wang, Shengjie Gao, Changhong Liu, Zhengzhu Zhang, Aijin Ma, Lei ZhengAbstractThe feasibility of using celery cellulose hydrogels as carriers was explored for controlled release of short-chain fatty acids (SCFAs) triggered by ultrasound. The hydrogels were prepared with the phase inversion method and further characterized using FT-IR, SEM and XRD techniques. At the optimal cellulose concentration (8.33 and 6.25 mg/mL), the hydrogels (F4 and F5) exhibited the swelling ratio of 185%, and Young's modulus of the F4 and F5 was lower...
Source: Food Chemistry - Category: Food Science Source Type: research
In this paper, a feasible method was proposed for the chlorine and fluorine determination in eye-pencil samples using ion chromatography (IC). The microwave-induced combustion (MIC) was used to digest up to 200 mg of a sample, with 50 mg of microcrystalline cellulose as a combustion aid and only water for analytes absorption. Cl and F recoveries were 105 ± 1 and 93 ± 5%, respectively, when standard solutions were used in the recovery tests. Certified reference materials (CRM) were also digested mixed to the sample, and no significant difference between the obtained results and the certified values was observe...
Source: Journal of the Brazilian Chemical Society - Category: Chemistry Source Type: research
A 63-year-old man was admitted 2 months after a deceased-donor kidney transplantation with an acute rise of his creatinine from a baseline of 1.9 mg/dl to 3.7 mg/dl. The patient had received basiliximab induction, followed by maintenance with belatacept, mycophenolic acid, and steroids. Physical examination and an ultrasound of the kidney transplant were unremarkable. Kidney biopsy revealed Banff acute cellular rejection grade IIB. Belatacept was replaced with tacrolimus, and steroid pulse and rabbit antithymocyte globulin were administered.
Source: Kidney International - Category: Urology & Nephrology Authors: Tags: Nephrology Image Source Type: research
More News: Biotechnology | Portugal Health | Ultrasound