WorldWideScience

Sample records for lacz transduced human

  1. lacZ transduced human breast cancer xenografts as an in vivo model for the study of invasion and metastasis

    DEFF Research Database (Denmark)

    Brünner, N; Thompson, E W; Spang-Thomsen, M;

    1992-01-01

    A number of human cancer cell lines have been described as being invasive and metastatic in immune incompetent animals. However, it is difficult to assess metastatic spread of a subcutaneously injected or inoculated cell line, since an exact detection of all microfoci of human tumour cells in the...

  2. Adeno-associated Virus Mediated LacZ Gene Transfect to Cultured Human Iris Pigment Epithelium Cells

    Institute of Scientific and Technical Information of China (English)

    Chun Zhang; Shibo Tang; Yan Luo; Xiaoling Liang; Jing Ma; Shaofen Lin

    2003-01-01

    Purpose: To study the feasibility of adeno-associated virus mediated gene transfection tocultured human iris pigment epithelium (IPE) cells in vitro.Methods: Recombinant replication deficient adeno-associated viruses (AAV) expressingLacZ gene were produced without helper virus. The LacZ gene was transduced into culturedhuman IPE cells.Results: Cultured human IPE cells stained positively anticytokeratin, The titer ofrAAV-LacZ was 2.1 × 108 virus particles/ml, 42% cultured human IPE cells expressedβ-galactosidase 7 days after transfection and 67% after 14 days.Conclusions: Recombined AAV produced without helper virus can transfer a foreign geneinto human IPE cells with high efficiency in vitro.

  3. TP53 and lacZ mutagenesis induced by 3-nitrobenzanthrone in Xpa-deficient human TP53 knock-in mouse embryo fibroblasts.

    Science.gov (United States)

    Kucab, Jill E; Zwart, Edwin P; van Steeg, Harry; Luijten, Mirjam; Schmeiser, Heinz H; Phillips, David H; Arlt, Volker M

    2016-03-01

    3-Nitrobenzanthrone (3-NBA) is a highly mutagenic compound and possible human carcinogen found in diesel exhaust. 3-NBA forms bulky DNA adducts following metabolic activation and induces predominantly G:CT:A transversions in a variety of experimental systems. Here we investigated the influence of nucleotide excision repair (NER) on 3-NBA-induced mutagenesis of the human tumour suppressor gene TP53 and the reporter gene lacZ. To this end we utilised Xpa -knockout (Xpa-Null) human TP53 knock-in (Hupki) embryo fibroblasts (HUFs). As Xpa is essential for NER of bulky DNA adducts, we hypothesized that DNA adducts induced by 3-NBA would persist in the genomes of Xpa-Null cells and lead to an increased frequency of mutation. The HUF immortalisation assay was used to select for cells harbouring TP53 mutations following mutagen exposure. We found that Xpa-Null Hupki mice and HUFs were more sensitive to 3-NBA treatment than their wild-type (Xpa-WT) counterparts. However, following 3-NBA treatment and immortalisation, a similar frequency of TP53-mutant clones arose from Xpa-WT and Xpa-Null HUF cultures. In cells from both Xpa genotypes G:CT:A transversion was the predominant TP53 mutation type and mutations exhibited bias towards the non-transcribed strand. Thirty-two percent of 3-NBA-induced TP53 mutations occurred at CpG sites, all of which are hotspots for mutation in smokers' lung cancer (codons 157, 158, 175, 245, 248, 273, 282). We also examined 3-NBA-induced mutagenesis of an integrated lacZ reporter gene in HUFs, where we again observed a similar mutant frequency in Xpa-WT and Xpa-Null cells. Our findings suggest that 3-NBA-DNA adducts may evade removal by global genomic NER; the persistence of 3-NBA adducts in DNA may be an important factor in its mutagenicity.

  4. The transducer domain is important for clamp operation in human DNA topoisomerase IIalpha

    DEFF Research Database (Denmark)

    Oestergaard, Vibe H; Bjergbaek, Lotte; Skouboe, Camilla

    2003-01-01

    the clamp to the enzyme core. Although structurally conserved, it is unclear whether the transducer domain is involved in clamp mechanism. We have purified and characterized a human topoisomerase II alpha enzyme with a two-amino acid insertion at position 408 in the transducer domain. The enzyme retains...

  5. Adeno-Associated Viral Vectors Transduce Mature Human Adipocytes in Three-Dimensional Slice Cultures.

    Science.gov (United States)

    Kallendrusch, Sonja; Schopow, Nikolas; Stadler, Sonja C; Büning, Hildegard; Hacker, Ulrich T

    2016-10-01

    Adipose tissue plays a pivotal role, both in the regulation of energy homeostasis and as an endocrine organ. Consequently, adipose tissue dysfunction is closely related to insulin resistance, morbid obesity, and metabolic syndrome. To study molecular mechanisms and to develop novel therapeutic strategies, techniques are required to genetically modify mature adipocytes. Here, we report on adeno-associated viral (AAV) vectors as a versatile tool to transduce human mature adipocytes in organotypic three-dimensional tissue cultures.

  6. Measurement of stapes vibration in Human temporal bones by round window stimulation using a 3-coil transducer.

    Science.gov (United States)

    Shin, Dong Ho; Kim, Dong Wook; Lim, Hyung Gyu; Jung, Eui Sung; Seong, Ki Woong; Lee, Jyung Hyun; Kim, Myoung Nam; Cho, Jin Ho

    2014-01-01

    Round window placement of a 3-coil transducer offers a new approach for coupling an implantable hearing aid to the inner ear. The transducer exhibits high performance at low-frequencies. One remarkable feature of the 3-coil transducer is that it minimizes leakage flux. Thus, the transducer, which consists of two permanent magnets and three coils, can enhance vibrational displacement. In human temporal bones, stapes vibration was observed by laser Doppler vibrometer in response to round window stimulation using the 3-coil transducer. Coupling between the 3-coil transducer and the round window was connected by a wire-rod. The stimulation created stapes velocity when the round window stimulated. Performance evaluation was conducted by measuring stapes velocity. To verify the performance of the 3-coil transducer, stapes velocity for round window and tympanic membrane stimulation were compared, respectively. Stapes velocity by round window stimulation using the 3-coil transducer was approximately 14 dB higher than that achieved by tympanic membrane stimulation. The study shows that 3-coil transducer is suitable for implantable hearing aids.

  7. Targeting signal transducers and activators of transcription (STAT) in human cancer by dietary polyphenolic antioxidants.

    Science.gov (United States)

    Amani, Hamed; Ajami, Marjan; Maleki, Solmaz Nasseri; Pazoki-Toroudi, Hamidreza; Daglia, Maria; Tsetegho Sokeng, Arold Jorel; Di Lorenzo, Arianna; Nabavi, Seyed Fazel; Devi, Kasi Pandima; Nabavi, Seyed Mohammad

    2017-08-11

    Over the course of the last three decades, a large body of evidence has shown that polyphenols, the secondary metabolites occurring in plant foods and beverages, exert protective effects due to their antioxidant activity mediated through different mechanisms ranging from direct radical scavenging and metal chelating activities, to the capacity to inhibit pro-oxidant enzymes and to target specific cell-signalling pathways. In the last decade, dietary components, and polyphenols in particular have gained considerable attention as chemopreventive agents against different types of cancer. The signal transducers and activators of transcription (STAT) family is a group of cytoplasmic transcription factors which interact with specific sequences of DNA, inducing the expression of specific genes which in turn give rise to adaptive and highly specific biological responses. Growing evidence suggests that, of the seven STAT members identified, STAT3 is over-expressed in many human tumors (i.e. solid tumors and hematological malignancies) promoting the onset and development of cancer in humans by inhibiting apoptosis or by inducing cell proliferation, angiogenesis, invasion, and metastasis. This review article aims to assess the most recent studies on the role of STATs, with focus on STAT3, in oncogenesis, and the promising effects of some polyphenols on STAT expression. Moreover, the mechanisms behind the anti-inflammatory and antioxidant activities of polyphenols which have an influence on STAT expression are discussed, with a focus on their ability to target specific cell-signalling pathways. Copyright © 2017 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.

  8. Noninvasively measuring oxygen saturation of human finger-joint vessels by multi-transducer functional photoacoustic tomography

    Science.gov (United States)

    Deng, Zijian; Li, Changhui

    2016-06-01

    Imaging small blood vessels and measuring their functional information in finger joint are still challenges for clinical imaging modalities. In this study, we developed a multi-transducer functional photoacoustic tomography (PAT) system and successfully imaged human finger-joint vessels from ˜1 mm to anatomical and functional information of individual finger-joint vessels with different sizes, which might help the study of finger-joint diseases, such as rheumatoid arthritis.

  9. Microinterferometer transducer

    Science.gov (United States)

    Corey, III, Harry S.

    1979-01-01

    An air-bearing microinterferometer transducer is provided for increased accuracy, range and linearity over conventional displacement transducers. A microinterferometer system is housed within a small compartment of an air-bearing displacement transducer housing. A movable cube corner reflector of the interferometer is mounted to move with the displacement gauging probe of the transducer. The probe is disposed for axial displacement by means of an air-bearing. Light from a single frequency laser is directed into an interferometer system within the transducer housing by means of a self-focusing fiber optic cable to maintain light coherency. Separate fringe patterns are monitored by a pair of fiber optic cables which transmit the patterns to a detecting system. The detecting system includes a bidirectional counter which counts the light pattern fringes according to the direction of movement of the probe during a displacement gauging operation.

  10. BIOSENSING TECHNICS FOR HUMAN DETECTION. 1. THE FROG SKIN TRANSDUCER: PRELIMINARY EXPERIMENT

    Science.gov (United States)

    Isolated frog skin used as a transducer whose bioelectrical potential is measured as a function of chemical species and concentration, is shown to...log units. A high degree of variability of response between frog skins, and a lack of data on ultimate sensitivities at usefully low levels for selected substances, are major problems that remain to be examined.

  11. In-vivo fusion of human cancer and hamster stromal cells permanently transduces and transcribes human DNA.

    Science.gov (United States)

    Goldenberg, David M; Rooney, Robert J; Loo, Meiyu; Liu, Donglin; Chang, Chien-Hsing

    2014-01-01

    After demonstrating, with karyotyping, polymerase chain reaction (PCR) and fluorescence in-situ hybridization, the retention of certain human chromosomes and genes following the spontaneous fusion of human tumor and hamster cells in-vivo, it was postulated that cell fusion causes the horizontal transmission of malignancy and donor genes. Here, we analyzed gene expression profiles of 3 different hybrid tumors first generated in the hamster cheek pouch after human tumor grafting, and then propagated in hamsters and in cell cultures for years: two Hodgkin lymphomas (GW-532, GW-584) and a glioblastoma multiforme (GB-749). Based on the criteria of MAS 5.0 detection P-values ≤0.065 and at least a 2-fold greater signal expression value than a hamster melanoma control, we identified 3,759 probe sets (ranging from 1,040 to 1,303 in each transplant) from formalin-fixed, paraffin-embedded sections of the 3 hybrid tumors, which unambiguously mapped to 3,107 unique Entrez Gene IDs, representative of all human chromosomes; however, by karyology, one of the hybrid tumors (GB-749) had a total of 15 human chromosomes in its cells. Among the genes mapped, 39 probe sets, representing 33 unique Entrez Gene IDs, complied with the detection criteria in all hybrid tumor samples. Five of these 33 genes encode transcription factors that are known to regulate cell growth and differentiation; five encode cell adhesion- and transmigration-associated proteins that participate in oncogenesis and/or metastasis and invasion; and additional genes encode proteins involved in signaling pathways, regulation of apoptosis, DNA repair, and multidrug resistance. These findings were corroborated by PCR and reverse transcription PCR, showing the presence of human alphoid (α)-satellite DNA and the F11R transcripts in additional tumor transplant generations. We posit that in-vivo fusion discloses genes implicated in tumor progression, and gene families coding for the organoid phenotype. Thus, cancer cells

  12. Acoustic transducer

    Science.gov (United States)

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  13. Simulations and Measurements of Human Middle Ear Vibrations Using Multi-Body Systems and Laser-Doppler Vibrometry with the Floating Mass Transducer

    OpenAIRE

    Tobias Strenger; Stefan Lehner; Frank Böhnke; Theodor Bretan

    2013-01-01

    The transfer characteristic of the human middle ear with an applied middle ear implant (floating mass transducer) is examined computationally with a Multi-body System approach and compared with experimental results. For this purpose, the geometry of the middle ear was reconstructed from μ-computer tomography slice data and prepared for a Multi-body System simulation. The transfer function of the floating mass transducer, which is the ratio of the input voltage and the generated force, is deri...

  14. Effect of Transducer Orientation on Errors in Ultrasound Image-Based Measurements of Human Medial Gastrocnemius Muscle Fascicle Length and Pennation.

    Science.gov (United States)

    Bolsterlee, Bart; Gandevia, Simon C; Herbert, Robert D

    2016-01-01

    Ultrasound imaging is often used to measure muscle fascicle lengths and pennation angles in human muscles in vivo. Theoretically the most accurate measurements are made when the transducer is oriented so that the image plane aligns with muscle fascicles and, for measurements of pennation, when the image plane also intersects the aponeuroses perpendicularly. However this orientation is difficult to achieve and usually there is some degree of misalignment. Here, we used simulated ultrasound images based on three-dimensional models of the human medial gastrocnemius, derived from magnetic resonance and diffusion tensor images, to describe the relationship between transducer orientation and measurement errors. With the transducer oriented perpendicular to the surface of the leg, the error in measurement of fascicle lengths was about 0.4 mm per degree of misalignment of the ultrasound image with the muscle fascicles. If the transducer is then tipped by 20°, the error increases to 1.1 mm per degree of misalignment. For a given degree of misalignment of muscle fascicles with the image plane, the smallest absolute error in fascicle length measurements occurs when the transducer is held perpendicular to the surface of the leg. Misalignment of the transducer with the fascicles may cause fascicle length measurements to be underestimated or overestimated. Contrary to widely held beliefs, it is shown that pennation angles are always overestimated if the image is not perpendicular to the aponeurosis, even when the image is perfectly aligned with the fascicles. An analytical explanation is provided for this finding.

  15. Ultrasonic transducer

    Science.gov (United States)

    Taylor, Steven C.; Kraft, Nancy C.

    2007-03-13

    An ultrasonic transducer having an effective center frequency of about 42 MHz; a bandwidth of greater than 85% at 6 dB; a spherical focus of at least 0.5 inches in water; an F4 lens; a resolution sufficient to be able to detect and separate a 0.005 inch flat-bottomed hole at 0.005 inches below surface; and a beam size of approximately 0.006–0.008 inches measured off a 11/2 mm ball in water at the transducer's focal point.

  16. The amino-terminal domain of human signal transducers and activators of transcription 1: Overexpression, purification and characterization

    Indian Academy of Sciences (India)

    Arati Prabhu; Evans Coutinho; Sudha Srivastava

    2005-12-01

    The dual functional signal transducers and activators of transcription (STAT) proteins are latent cytoplasmic transcription factors that play crucial roles in host defense. Animals that lack these proteins are highly susceptible to microbial and viral infections and chemically induced primary tumours. We have over expressed the aminoterminal domain of human STAT1 (hSTAT1) in Escherichia coli and purified it by affinity chromatography and gel filtration chromatography. The entire process has been monitored by gel electrophoresis. The pure protein has been characterized by mass spectrometry and 2-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy. Our results indicate that the N-terminus of hSTAT1 exists as a dimer in solution.

  17. Pressure transducer

    Science.gov (United States)

    Anderson, Thomas T.; Roop, Conard J.; Schmidt, Kenneth J.; Gunchin, Elmer R.

    1989-01-01

    A pressure transducer suitable for use in high temperature environments includes two pairs of induction coils, each pair being bifilarly wound together, and each pair of coils connected as opposite arms of a four arm circuit; an electrically conductive target moveably positioned between the coil pairs and connected to a diaphragm such that deflection of the diaphragm causes axial movement of the target and an unbalance in the bridge output.

  18. Expression of human adenosine deaminase in mice reconstituted with retrovirus-transduced hematopoietic stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, J.M.; Danos, O.; Grossman, M.; Raulet, D.H.; Mulligan, R.C. (Massachusetts Institute of Technology, Cambridge (USA))

    1990-01-01

    Recombinant retroviruses encoding human adenosine deaminase have been used to infect murine hematopoietic stem cells. In bone marrow transplant recipients reconstituted with the genetically modified cells, human ADA was detected in peripheral blood mononuclear cells of the recipients for at least 6 months after transplantation. In animals analyzed in detail 4 months after transplantation, human ADA and proviral sequences were detected in all hematopoietic lineages; in several cases, human ADA activity exceeded the endogenous activity. These studies demonstrate the feasibility of introducing a functional human ADA gene into hematopoietic stem cells and obtaining expression in multiple hematopoietic lineages long after transplantation. This approach should be helpful in designing effective gene therapies for severe combined immunodeficiency syndromes in humans.

  19. Evaluation of Round Window Stimulation Using the Floating Mass Transducer by Intracochlear Sound Pressure Measurements in Human Temporal Bones

    Science.gov (United States)

    Nakajima, Hideko Heidi; Dong, Wei; Olson, Elizabeth S.; Rosowski, John J.; Ravicz, Michael E.; Merchant, Saumil N.

    2009-01-01

    Hypothesis Round window (RW) stimulation with a floating mass transducer (FMT) can be studied experimentally and optimized to enhance auditory transduction. Background The FMT (MED-EL Vibrant Soundbridge) has been recently implanted in patients with refractory conductive or mixed hearing loss to stimulate the RW with varying degrees of success. The mechanics of RW stimulation with the FMT have not been studied in a systematic manner. Methods In cadaveric human temporal bones, measurements of stapes velocity with laser vibrometry in response to FMT-RW stimulation were used to optimize FMT insertion. The effect of RW stimulation on hearing was estimated using simultaneous measurements of intracochlear pressures in both perilymphatic scalae with micro-optical pressure transducers. This enabled calculation of the differential pressure across the cochlear partition, which is directly tied to auditory transduction. Results The best coupling between the FMT and RW was achieved with a piece of fascia placed between the RW and the FMT, and by "bracing" the free end of the FMT against the hypotympanic wall with dental impression material. FMT-RW stimulation provided differential pressures comparable to sound-induced oval window stimulation above 1 kHz. However, below 1 kHz the FMT was less capable. Conclusions Measurements of stapes velocity and intracochlear sound pressures in scala vestibuli and scala tympani enabled experimental evaluation of FMT stimulation of the RW. The efficacy of FMT-RW coupling was influenced significantly by technical and surgical factors, which can be optimized. This temporal bone preparation also lays the foundation for future studies to investigate multiple issues of relevance to both basic and clinical science such as RW stimulation in stapes fixation, non-aerated middle-ears and third-window lesions, and to answer basic questions regarding bone conduction. PMID:19841600

  20. Comparison between Sendai virus and adenovirus vectors to transduce HIV-1 genes into human dendritic cells.

    Science.gov (United States)

    Hosoya, Noriaki; Miura, Toshiyuki; Kawana-Tachikawa, Ai; Koibuchi, Tomohiko; Shioda, Tatsuo; Odawara, Takashi; Nakamura, Tetsuya; Kitamura, Yoshihiro; Kano, Munehide; Kato, Atsushi; Hasegawa, Mamoru; Nagai, Yoshiyuki; Iwamoto, Aikichi

    2008-03-01

    Immuno-genetherapy using dendritic cells (DCs) can be applied to human immunodeficiency virus type 1 (HIV-1) infection. Sendai virus (SeV) has unique features such as cytoplasmic replication and high protein expression as a vector for genetic manipulation. In this study, we compared the efficiency of inducing green fluorescent protein (GFP) and HIV-1 gene expression in human monocyte-derived DCs between SeV and adenovirus (AdV). Human monocyte-derived DCs infected with SeV showed the maximum gene expression 24 hr after infection at a multiplicity of infection (MOI) of 2. Although SeV vector showed higher cytopathic effect on DCs than AdV, SeV vector induced maximum gene expression earlier and at much lower MOI. In terms of cell surface phenotype, both SeV and AdV vectors induced DC maturation. DCs infected with SeV as well as AdV elicited HIV-1 specific T-cell responses detected by interferon gamma (IFN-gamma) enzyme-linked immunospot (Elispot). Our data suggest that SeV could be one of the reliable vectors for immuno-genetherapy for HIV-1 infected patients.

  1. Ethanol metabolism by HeLa cells transduced with human alcohol dehydrogenase isoenzymes: control of the pathway by acetaldehyde concentration.

    Science.gov (United States)

    Matsumoto, Michinaga; Cyganek, Izabela; Sanghani, Paresh C; Cho, Won Kyoo; Liangpunsakul, Suthat; Crabb, David W

    2011-01-01

    Human class I alcohol dehydrogenase 2 isoenzymes (encoded by the ADH1B locus) have large differences in kinetic properties; however, individuals inheriting the alleles for the different isoenzymes exhibit only small differences in alcohol elimination rates. This suggests that other cellular factors must regulate the activity of the isoenzymes. The activity of the isoenzymes expressed from ADH1B*1, ADH1B*2, and ADH1B*3 cDNAs was examined in stably transduced HeLa cell lines, including lines which expressed human low K(m) aldehyde dehydrogenase (ALDH2). The ability of the cells to metabolize ethanol was compared with that of HeLa cells expressing rat class I alcohol dehydrogenase (ADH) (HeLa-rat ADH cells), rat hepatoma (H4IIEC3) cells, and rat hepatocytes. The isoenzymes had similar protein half-lives in the HeLa cells. Rat hepatocytes, H4IIEC3 cells, and HeLa-rat ADH cells oxidized ethanol much faster than the cells expressing the ADH1B isoenzymes. This was not explained by high cellular NADH levels or endogenous inhibitors; but rather because the activity of the β1 and β2 ADHs was constrained by the accumulation of acetaldehyde, as shown by the increased rate of ethanol oxidation by cell lines expressing β2 ADH plus ALDH2. The activity of the human β2 ADH isoenzyme is sensitive to inhibition by acetaldehyde, which likely limits its activity in vivo. This study emphasizes the importance of maintaining a low steady-state acetaldehyde concentration in hepatocytes during ethanol metabolism. Copyright © 2010 by the Research Society on Alcoholism.

  2. The mutation detection system of repackaged lambda phage containing LacZ gene

    Institute of Scientific and Technical Information of China (English)

    LiuY; CaoJ

    2002-01-01

    The mutation detection system of repackaged lambda phage has been constructed.the mutagen-treated lambda DNA with LacZ gene was repackaged in vitro and the packaged lambda phages were then grown in e.coli Y1090 on a selective plate containing x-gal and isopropylthio-β-D-galactoside.the survival and mutation frequency was determined by counting the clearplaque mutants,the molecular mutation mechanisms of 1-ethyl-1-nitrosourea(ENU) and 9-aminoacridine(9-AA) were further studied by extracting and sequencing the LacZ gene of the mutants.The results demonstrated that the mutation detection system of repackaged lambda gtll DNA containing LacZ gene was not only simple,cheap and timesaving,but also was high specific and high sensitive.Then it is possible for this system to be used as a preliminary mutation screening for chemicals by analyzing the survival of the packaged phages and the mutation frequency,and it's also possible used to analyze the molecular mutation mechanism be sequencing the partial or entire LacZ gene.

  3. Selective response of human airway epithelia to luminal but not serosal solution hypertonicity. Possible role for proximal airway epithelia as an osmolality transducer

    DEFF Research Database (Denmark)

    Willumsen, Niels J.; Davis, C.W.; Boucher, R.C.

    1994-01-01

    exposure (10 min) to 430 mosM luminal solution elicited no regulation of any parameter. Optical measurements revealed a reduction in the thickness of preparations only in response to luminal hypertonic solutions. We conclude that (a) airway epithelial cells exhibit asymmetric water transport properties......- secretion; and (d) cell volume loss increases the resistance of the paracellular path. We speculate that these properties configure human nasal epithelium to behave as an osmotic sensor, transducing information about luminal solutions to the airway wall....

  4. Mutagenicity of the peroxisome proliferators clofibrate, Wyeth 14,643 and di-2-ethylhexyl phthalate in the lacZ plasmid-based transgenic mouse mutation assay

    Directory of Open Access Journals (Sweden)

    Boerrigter Michaël

    2004-01-01

    Full Text Available Abstract Background Peroxisome proliferators are considered rodent carcinogens that are putative human non-carcinogens based on the presumed absence of direct genetic toxicity in rodent and human cells and the resistance of human cells to the induction of peroxisomes by peroxisome proliferators. The highly sensitive lacZ plasmid-based transgenic mouse mutation assay was employed to investigate the mutagenicity of several peroxisome proliferators based on several lines of evidence suggesting that these agents may in fact exert a genotoxic effect. Methods Male and female lacZ-plasmid based transgenic mice were treated at 4 months of age with 6 doses of 2,333 mg di-2-ethylhexyl phthalate (DHEP, 200 mg Wyeth-14,643, or 90 mg clofibrate per kg of bodyweight, respectively, over a two-week period. Control animals were treated with the respective vehicles only (35% propyl glycol for DEHP and Wyeth-14,643 treatment controls and sterile water for clofibrate treatment controls. The mutant frequency in liver, kidney and spleen DNA was determined as the proportion of retrieved mutant and wild-type lacZ plasmids expressed in Escherichia Coli C host cells employing a positive selection system for mutant plasmids. Results Exposure to DEHP or Wyeth-14,643 significantly increased the mutant frequency in liver, but not in kidney or spleen, of both female and male mice. Treatment with clofibrate did not lead to an increased mutant frequency in any of the organs studied. Conclusion The results indicate that some peroxisome proliferators display an organ-specific mutagenicity in lacZ plasmid-based transgenic mice consistent with historical observations of organ- and compound-specific carcinogenicity.

  5. Expression of the lacZ gene in Escherichia coli irradiated with gamma rays

    Directory of Open Access Journals (Sweden)

    Mikio Kato

    2014-10-01

    Full Text Available Exposure of bacterial cells to ionizing radiation damages cellular components and causes cell death. We examined the induction of the plasmid-encoded lacZ gene in Escherichia coli JM109 harboring pUC19 after irradiation with gamma rays. The data demonstrated that cells irradiated with 6 or 8 kGy gamma rays lost their ability to grow on nutrient agar plates, but retained the ability to induce lacZ gene expression by IPTG at about 10% the level of the nonirradiated control. Thus, inactivation of cells by irradiation may provide another option for establishing a vehicle of protein and DNA, as nonpropagating protein-producing apparatus, albeit with lower capacity than intact cells.

  6. New mutation detection system of repackaged λ gt11 DNA containing LacZ gene

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; CAO Jia; WU Tao; YANG Lu-jun; SUN Hua-ming; YANG Ming-jie; QIAN Ping

    2002-01-01

    Objective: To establish a reformative detection system which has sound ability of providing information on molecular mutagenesis spectrum and the specificity of detection system of repackaged λ phage.Methods: LacZ gene, as mutational target gene and reporter gene, was applied into the detection system.The λ gt11 DNA treated with ENU (1-ethyl-1-nitrosourea) and 9-AA (9-aminoacridine) was repackaged in vitro. The packaged λ phage was then grown in E. coli Y1090 on a selective plate containing X-gel and IPTG. The survival and mutation frequencies were determined by counting the clear-plaque and blue-plaque,and the molecular mutation mechanism was studied by extracting and sequencing the LacZ gene of mutants.Results: The survival of repackaged λ phages treated with 9-AA and ENU apparently decreased in consistent dose-dependence. The mutation frequency of clear-plaque mutants showed a linear dose-related increase. The predominant mutations induced by 9-AA were ±1 frameshift mutation, and 9-AA induced -1 frameshift was much more effective than induced + 1 frameshift. 9-AA also induced substitutions with transversions more common. ENU-induced mutations were chiefly occurred at G: C sites. Substitutions induced by ENU were mainly G: C→A: T, G: C→C: G and A: T→T: A transversion. Conclusion: Mutation detection system of λgt11 DNA containing LacZ gene is proven better than that of λDNA without LacZ gene. The combination of survival, mutant frequency and sequence spectrum can not only increase the sensitivity and specificity of the new method, but also provide a better understanding of the molecular mechanism of mutation for ultimate extrapolation to risk assessment.

  7. Macro tree transducers

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1985-01-01

    Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical

  8. Megahertz tonpilz transducer

    Science.gov (United States)

    Van Tol, Dave; Hughes, W. Jack

    1999-06-01

    The tonpilz configuration is applied to a transducer operating in the megahertz frequency range. The KLM model is used to design the transducer using readily available components. The construction techniques used are the same as those applied to standard high frequency transducers. Modeled and measured pulse-echo results display a high level of agreement, but impedance and sensitivity comparisons are less promising.

  9. Macro tree transducers

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1985-01-01

    Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical

  10. Simulations and Measurements of Human Middle Ear Vibrations Using Multi-Body Systems and Laser-Doppler Vibrometry with the Floating Mass Transducer

    Directory of Open Access Journals (Sweden)

    Tobias Strenger

    2013-10-01

    Full Text Available The transfer characteristic of the human middle ear with an applied middle ear implant (floating mass transducer is examined computationally with a Multi-body System approach and compared with experimental results. For this purpose, the geometry of the middle ear was reconstructed from μ-computer tomography slice data and prepared for a Multi-body System simulation. The transfer function of the floating mass transducer, which is the ratio of the input voltage and the generated force, is derived based on a physical context. The numerical results obtained with the Multi-body System approach are compared with experimental results by Laser Doppler measurements of the stapes footplate velocities of five different specimens. Although slightly differing anatomical structures were used for the calculation and the measurement, a high correspondence with respect to the course of stapes footplate displacement along the frequency was found. Notably, a notch at frequencies just below 1 kHz occurred. Additionally, phase courses of stapes footplate displacements were determined computationally if possible and compared with experimental results. The examinations were undertaken to quantify stapes footplate displacements in the clinical practice of middle ear implants and, also, to develop fitting strategies on a physical basis for hearing impaired patients aided with middle ear implants.

  11. 21 CFR 890.1615 - Miniature pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Miniature pressure transducer. 890.1615 Section 890.1615 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miniature pressure transducer. (a) Identification. A miniature pressure transducer is a device intended for...

  12. 21 CFR 870.2870 - Catheter tip pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter tip pressure transducer. 870.2870 Section 870.2870 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into...

  13. 21 CFR 870.2840 - Apex cardiographic transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Apex cardiographic transducer. 870.2840 Section 870.2840 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... cardiographic transducer. (a) Identification. An apex cardiographic transducer is a device used to detect motion...

  14. 21 CFR 868.2875 - Differential pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Differential pressure transducer. 868.2875 Section 868.2875 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... transducer. (a) Identification. A differential pressure transducer is a two-chambered device intended for...

  15. Brain transplantation of human neural stem cells transduced with tyrosine hydroxylase and GTP cyclohydrolase 1 provides functional improvement in animal models of Parkinson disease.

    Science.gov (United States)

    Kim, Seung U; Park, In H; Kim, Tae H; Kim, Kwang S; Choi, Hyun B; Hong, Seok H; Bang, Jung H; Lee, Myung A; Joo, In S; Lee, Chong S; Kim, Yong S

    2006-04-01

    Parkinson disease is a neurodegenerative disease characterized by loss of midbrain dopaminergic neurons resulting in movement disorder. Neural stem cells (NSC) of the CNS have recently aroused a great deal of interest, not only because of their importance in basic research of neural development, but also for their therapeutic potential in neurological disorders. We have recently generated an immortalized human NSC cell line, HB1.F3, via retrovirus-mediated v-myc transfer. This line is capable of self-renewal, is multipotent, and expresses cell specific markers for NSC, ATP-binding cassettes transporter (ABCG2) and nestin. Next, we co-transduced the F3 NSC line with genes encoding tyrosine hydroxylase (TH) and GTP cyclohydrolase 1 (GTPCH1) in order to generate dopamine-producing NSC. The F3.TH.GTPCH human NSC line expresses TH and GTPCH phenotypes as determined by RT-PCR, western blotting and immunocytochemistry, and shows a 800 to 2000-fold increase in production of L-dihydroxyphenyl alanine in HPLC analysis. A marked improvement in amphetamine-induced turning behavior was observed in parkinsonian rats implanted with F3.TH.GTPCH cells, but not in control rats receiving F3 NSC. In the animals showing functional improvement, a large number of TH-positive F3.TH.GTPCH NSC were found at injection sites. These results indicate that human NSC, genetically transduced with TH and GTPCH1 genes, have great potential in clinical utility for cell replacement therapy in patients suffering from Parkinson disease.

  16. Hemato-endothelial differentiation from lentiviral-transduced human embryonic stem cells retains durable reporter gene expression under the control of ubiquitin promoter.

    Science.gov (United States)

    Jiang, Hua; Lin, Xiaolong; Feng, Youji; Xie, Yi; Han, Jinlan; Zhang, Yueping; Wang, Zack Z; Chen, Tong

    2010-01-01

    Human embryonic stem (hES) cells are able to give rise to a variety of cell lineages under specific culture condition. An effective strategy for stable genetic modification in hES cells may provide a powerful tool for study of human embryogenesis and cell-based therapies. However, gene silences are documented in hES cells. In current study, we investigated whether genes controlled under ubiquitin promoter are expressed during hematopoietic-endothelial differentiation in hES cells. Undifferentiated hES cells (H1) were transduced by lentivirus encoding green fluorescent protein (GFP) gene under ubiquitin promoter. GFP-expressing hES cells (GFP-H1) were established after several rounds of mechanical selection under fluorescence microscope. GFP gene was stably expressed in hES cells throughout prolonged (> 50 passages) cultivation, and in differentiated embryo body (EB) and teratoma. Hematopoietic and endothelial markers, including KDR (VEGFR2), CD34, CD31, Tie-2, GATA-1 and GATA-2, were expressed at similar levels during hES cell differentiation in parent hES cells and GFP-H1 hES cells. CD34(+) cells isolated from GFP-H1 hES cells were capable to generate hematopoietic colony-forming cells and tubular structure-forming cells. Differentiated GFP-EB formed vasculature structures in a semi-solid sprouting EB model. These results indicated that a transgene under ubiquitin promoter in lentiviral transduced hES cells retained its expression in undifferentiated hES cells and in hES-derived hematopoietic and endothelial cells. With the view of embryonic mesodermal developing events in humans, genetic modification of hES cells by lentiviral vectors provides a powerful tool for study of hematopoiesis and vasculogenesis.

  17. Handbook of force transducers

    CERN Document Server

    Stefanescu, Dan Mihai

    2011-01-01

    Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

  18. Gas speed flow transducer

    Directory of Open Access Journals (Sweden)

    Godovaniouk V. N.

    2011-08-01

    Full Text Available The design of a gas speed flow transducer using the coupling of gas speed and heat streams within the transducer itself is proposed. To maintain the heat balance between two thermoresistors under gas stream at different temperatures, it provides energy consumption monitoring. The detailed combined planar technology for the transducer production is presented. The worked-out measurement procedure allows to make measurements in the temperature range. Information enough to organize production of cheap, reliable and precise gas speed flow transducers is given.

  19. Driving electrostatic transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed......, and a high voltage attenuation interface for an audio analyzer is presented. THD below 0:1% is reported....

  20. An Inexpensive Position Transducer.

    Science.gov (United States)

    Fox, J.; And Others

    1989-01-01

    Described is a position transducer used to convert the position of an object into a voltage read by a computer with use of an interface board. The arrangement of the apparatus, electronic circuit, and typical graph displays are presented. Discussed is the instructional use of the transducer. (YP)

  1. Modeling of ultrasound transducers

    DEFF Research Database (Denmark)

    Bæk, David

    deviation of 5.5 % to 11.0 %. Finite element modeling of piezoceramics in combination with Field II is addressed and reveals the influence of restricting the modeling of transducers to the one-dimensional case. An investigation on modeling capacitive micromachined ultrasonic transducers (CMUT)s with Field......This Ph.D. dissertation addresses ultrasound transducer modeling for medical ultrasound imaging and combines the modeling with the ultrasound simulation program Field II. The project firstly presents two new models for spatial impulse responses (SIR)s to a rectangular elevation focused transducer...... II is addressed. It is shown how a single circular CMUT cell can be well approximated with a simple square transducer encapsulating the cell, and how this influence the modeling of full array elements. An optimal cell discretization with Field II’s mathematical elements is addressed as well...

  2. Triple-resonant transducers.

    Science.gov (United States)

    Butler, Stephen C

    2012-06-01

    A detailed analysis is presented of two novel multiple-resonant transducers which produce a wider transmit response than that of a conventional Tonpilz-type transducer. These multi-resonant transducers are Tonpilz-type longitudinal vibrators that produce three coupled resonances and are referred to as triple-resonant transducers (TRTs). One of these designs is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, second central mass, second compliant spring, and a piston-radiating head mass. The other TRT design is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, and head mass with a quarter-wave matching layer of poly(methyl methacrylate) on the head mass. Several prototype transducer element designs were fabricated that demonstrated proof-of-concept.

  3. Programming macro tree transducers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Day, Laurence E.

    2013-01-01

    A tree transducer is a set of mutually recursive functions transforming an input tree into an output tree. Macro tree transducers extend this recursion scheme by allowing each function to be defined in terms of an arbitrary number of accumulation parameters. In this paper, we show how macro tree...... transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...... definition of (macro) tree transducers, abolishing a restriction on finite state spaces. However, as we demonstrate, this generalisation does not affect compositionality....

  4. Programming macro tree transducers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Day, Laurence E.

    2013-01-01

    A tree transducer is a set of mutually recursive functions transforming an input tree into an output tree. Macro tree transducers extend this recursion scheme by allowing each function to be defined in terms of an arbitrary number of accumulation parameters. In this paper, we show how macro tree...... transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...... definition of (macro) tree transducers, abolishing a restriction on finite state spaces. However, as we demonstrate, this generalisation does not affect compositionality....

  5. Inhibition of signal transducer and activator of transcription 3 expression by RNA interference suppresses invasion through inducing anoikis in human colon cancer cells

    Institute of Scientific and Technical Information of China (English)

    Yu Fan; You-Li Zhang; Ying Wu; Wei Zhang; Yin-Huan Wang; Zhao-Ming Cheng; Hua Li

    2008-01-01

    AIM: To investigate the roles and mechanism of signal transducer and activator of transcription 3 (STAT3) in invasion of human colon cancer cells by RNA interference. METHODS: Small interfering RNA (siRNA) targeting Signal transducer and activator of transcription 3 (STAT3) was transfected into HT29 colon cancer cells. STAT3 protein level and DNA-binding activity of STAT3 was evaluated by western blotting and electrophoretic mobility shift assay (EMSA), respectively. We studied the anchorage-independent growth using colony formation in soft agar, and invasion using the boyden chamber model, anoikis using DNA fragmentation assay and terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL), respectively. Western blot assay was used to observe the protein expression of Bcl-xL and survivin in colon cancer HT29 cells. RESULTS: RNA interference (RNAi) mediated by siRNA leads to suppression of STAT3 expression in colon cancer cell lines. Suppression of STAT3 expression by siRNA could inhibit anchorage-independent growth, and invasion ability, and induces anoikis in the colon cancer cell line HT29. It has been shown that knockdown of STAT3 expression by siRNA results in a reduction in expression of Bcl-xL and survivin in HT29 cells. CONCLUSION: These results suggest that STAT3 siRNA can inhibit the invasion ability of colon cancer cells through inducing anoikis, which antiapoptotic genes survivin and Bcl-xL contribute to regulation of anoikis. These studies indicate STAT3 siRNA could be a useful therapeutic tool for the treatment of colon cancer.

  6. Compact Transducers and Arrays

    Science.gov (United States)

    2005-05-01

    Soc. Am., 104, pp.64-71 44 25.Decarpigny, J.N., J.C. Debus, B. Tocquet & D. Boucher. 1985. "In-Air Analysis Of Piezoelectric Tonpilz Transducers In A... Transducers and Arrays Final Report May 2005 Contacts: Dr. Robert E. Newnham The Pennsylvania State University, 251 MRL, University Park, PA 16802 phone...814) 865-1612 fax: (814) 865-2326 email: ....c xx.....i.i.....ht.. .u a.p.u..c.e.du. Dr. Richard J. Meyer, Jr. Systems Engineering ( Transducers ), ARL

  7. Pressure Transducer Locations

    Data.gov (United States)

    National Aeronautics and Space Administration — Files are located here, defining the locations of the pressure transducers on the HIRENASD model. These locations also correspond to the locations that analysts...

  8. Signal transducer and activator of transcription 3 is involved in cell growth and survival of human rhabdomyosarcoma and osteosarcoma cells

    Directory of Open Access Journals (Sweden)

    Qualman Stephen J

    2007-06-01

    Full Text Available Abstract Background Stat3 has been classified as a proto-oncogene and constitutive Stat3 signaling appears to be involved in oncogenesis of human cancers. However, whether constitutive Stat3 signaling plays a role in the survival and growth of osteosarcomas, rhabdomyosarcomas, and soft-tissue sarcomas is still unclear. Methods To examine whether Stat3 is activated in osteosarcomas, rhabdomyosarcomas and other soft-tissue sarcomas we analyzed sarcoma tissue microarray slides and sarcoma cell lines using immunohistochemistry and Western blot analysis, respectively, with a phospho-specific Stat3 antibody. To examine whether the activated Stat3 pathway is important for sarcoma cell growth and survival, adenovirus-mediated expression of a dominant-negative Stat3 (Y705F and a small molecule inhibitor (termed STA-21 were used to inhibit constitutive Stat3 signaling in human sarcoma cell lines expressing elevated levels of Stat3 phosphorylation. Cell viability was determined by MTT assays and induction of apoptosis was analyzed by western blotting using antibodies that specifically recognize cleaved caspases-3, 8, and 9. Results Stat3 phosphorylation is elevated in 19% (21/113 of osteosarcoma, 27% (17/64 of rhabdomyosarcoma, and 15% (22/151 of other soft-tissue sarcoma tissues as well as in sarcoma cell lines. Expression of the dominant-negative Stat3 and treatment of STA-21 inhibited cell viability and growth and induced apoptosis through caspases 3, 8 and 9 pathways in human sarcoma cell lines expressing elevated levels of phosphorylated Stat3. Conclusion This study demonstrates that Stat3 phosphorylation is elevated in human rhabdomyosarcoma, osteosarcomas and soft-tissue sarcomas. Furthermore, the activated Stat3 pathway is important for cell growth and survival of human sarcoma cells.

  9. Estimate of the attenuation coefficient using a clinical array transducer for the detection of cervical ripening in human pregnancy.

    Science.gov (United States)

    Labyed, Yassin; Bigelow, Timothy A; McFarlin, Barbara L

    2011-01-01

    Premature delivery is the leading cause of infant mortality in the United States. Currently, premature delivery cannot be prevented and new treatments are difficult to develop due to the inability to diagnose symptoms prior to uterine contractions. Cervical ripening is a long period that precedes the active phase of uterine contractions and cervical dilation. The changes in the microstructure of the cervix during cervical ripening suggest that the ultrasonic attenuation should decrease. The objective of this study is to use the reference phantom algorithm to estimate the ultrasonic attenuation in the cervix of pregnant human patients. Prior to applying the algorithm to in vivo human data, two homogeneous phantoms with known attenuation coefficients were used to validate the algorithm and to find the length and the width of the region of interest (ROI) that achieves the smallest error in the attenuation coefficient estimates. In the phantom data, we found that the errors in the attenuation coefficients estimates are less than 12% for ROIs that contain 40 wavelengths or more axially and 30 echo lines or more laterally. The reference phantom algorithm was then used to obtain attenuation maps of the echoes from two human pregnant cervices at different gestational ages. It was observed that the mean of the attenuation coefficient estimates in the cervix of the patient at a more advanced gestational age is smaller than the mean of the attenuation coefficient estimates in the cervix of the patient at an earlier gestational age which suggests that ultrasonic attenuation decreases with increasing gestational age. We also observed a large variance between the attenuation coefficient estimates in the different regions of the cervix due to the natural variation in tissue micro-structures across the cervix. The preliminary results indicate that the algorithm could potentially provide an important diagnostic tool for diagnosing the risk of premature delivery. Copyright © 2010

  10. Human tumor-derived genomic DNA transduced into a recipient cell induces tumor-specific immune responses ex vivo

    OpenAIRE

    2002-01-01

    This article describes a DNA-based vaccination strategy evaluated ex vivo with human cells. The vaccine was prepared by transferring tumor-derived genomic DNA to PCI-13 cells, a highly immunogenic tumor cell line (“recipient cell”), which had been genetically modified to secrete IL-2 (PCI-13/IL-2). PCI-13 cells expressed class I MHC determinants (HLA-A2) shared with the tumor from which the DNA was obtained as well as allogeneic determinants. DNA from a gp100+ melanoma ce...

  11. Signal transducer and activator of transcription 3 and 5 regulate system Xc- and redox balance in human breast cancer cells.

    Science.gov (United States)

    Linher-Melville, Katja; Haftchenary, Sina; Gunning, Patrick; Singh, Gurmit

    2015-07-01

    System Xc- is a cystine/glutamate antiporter that contributes to the maintenance of cellular redox balance. The human xCT (SLC7A11) gene encodes the functional subunit of system Xc-. Transcription factors regulating antioxidant defense mechanisms including system Xc- are of therapeutic interest, especially given that aggressive breast cancer cells exhibit increased system Xc- function. This investigation provides evidence that xCT expression is regulated by STAT3 and/or STAT5A, functionally affecting the antiporter in human breast cancer cells. Computationally analyzing two kilobase pairs of the xCT promoter/5' flanking region identified a distal gamma-activated site (GAS) motif, with truncations significantly increasing luciferase reporter activity. Similar transcriptional increases were obtained after treating cells transiently transfected with the full-length xCT promoter construct with STAT3/5 pharmacological inhibitors. Knock-down of STAT3 or STAT5A with siRNAs produced similar results. However, GAS site mutation significantly reduced xCT transcriptional activity, suggesting that STATs may interact with other transcription factors at more proximal promoter sites. STAT3 and STAT5A were bound to the xCT promoter in MDA-MB-231 cells, and binding was disrupted by pre-treatment with STAT inhibitors. Pharmacologically suppressing STAT3/5 activation significantly increased xCT mRNA and protein levels, as well as cystine uptake, glutamate release, and total levels of intracellular glutathione. Our data suggest that STAT proteins negatively regulate basal xCT expression. Blocking STAT3/5-mediated signaling induces an adaptive, compensatory mechanism to protect breast cancer cells from stress, including reactive oxygen species, by up-regulating xCT expression and the function of system Xc-. We propose that targeting system Xc- together with STAT3/5 inhibitors may heighten therapeutic anti-cancer effects.

  12. Transcriptional Regulatory Networks Activated by PI3K and ERK Transduced Growth Signals in Human Glioblastoma Cells

    Institute of Scientific and Technical Information of China (English)

    Peter M. Haverty; Zhi-Ping Weng; Ulla Hansen

    2005-01-01

    Determining how cells regulate their transcriptional response to extracellular signals is key to the understanding of complex eukaryotic systems. This study was initiated with the goals of furthering the study of mammalian transcriptional regulation and analyzing the relative benefits of related computational methodologies. One dataset available for such an analysis involved gene expression profiling of the early growth factor response to platelet derived growth factor (PDGF)in a human glioblastoma cell line; this study differentiated genes whose expression was regulated by signaling through the phosphoinositide-3-kinase (PI3K) versus the extracellular-signal regulated kinase (ERK) pathways. We have compared the inferred transcription factors from this previous study with additional predictions of regulatory transcription factors using two alternative promoter sequence analysis techniques. This comparative analysis, in which the algorithms predict overlapping,although not identical, sets of factors, argues for meticulous benchmarking of promoter sequence analysis methods to determine the positive and negative attributes that contribute to their varying results. Finally, we inferred transcriptional regulatory networks deriving from various signaling pathways using the CARRIE program suite. These networks not only included previously described transcriptional features of the response to growth signals, but also predicted new regulatory features for the propagation and modulation of the growth signal.

  13. Suppression of human lung cancer cell proliferation and metastasis in vitro by the transducer of ErbB-2.1(TOB1)

    Institute of Scientific and Technical Information of China (English)

    Yang JIAO; Ke-kang SUN; Lin ZHAO; Jia-ying XU; Li-li Wang; Sai-jun FAN

    2012-01-01

    Aim:To investigate the effects of the transducer of ErbB-2.1 (TOB1) on the proliferation,migration and invasion of human lung cancer cells in vitro.Methods:Human lung cancer cell lines (95-D,A549,NCI-H1299,NCI-H1975,NCI-H661,NCI-H446,NCI-H1395,and Calu-3)and the normal human bronchial epithelial (HBE) cell line were tested.The expression levels of TOB1 in the cells were determined with Western blot and RT-PCR analyses.TOB1-overexpressing cell line 95-D/TOB1 was constructed using lipofectamine-induced TOB1 recombinant plasmid transfection and selective G418 cell culture.The A549 cells were transcend-transfected with TOB1-siRNA.MTT assay,flow cytometry and Western blot analysis were used to examine the effects of TOB1 on cancer cell proliferation and wound healing.Transwell invasive assay was performed to evaluate the effects of TOB1 on cancer cell migration and invasion.The activity of MMP2 and MMP9 was measured using gelatin zymography assay.Results:The expression levels of TOB1 in the 8 human lung cancer cell lines were significantly lower than that in HBE cells.TOB1 overexpression inhibited the proliferation of 95-D cells,whereas TOB1 knockdown with TOB1-siRNA promoted the growth of A549 cells.Decreased cell migration and invasion were detected in 95-D/TOB1 cells,and the suppression of TOB1 enhanced the metastasis in A549 cells.TOB1 overexpression not only increased the expression of the phosphatase and tensin homolog (PTEN),an important tumor suppressor,but also regulated the downstream effectors in the PI3K/PTEN signaling pathway,including Akt,ERK1/2,etc.In contrast,decreased expression of TOB1 oppositely regulated the expression of these factors.TOB1 also regulates the gelatinase activity of MMP2 and MMP9 in lung cancer cells.Conclusion:The results demonstrate that the PI3K/PTEN pathway,which is essential for carcinogenesis,angiogenesis,and metastasis,may be one of the possible signaling pathways for regulation of proliferation and metastasis of human lung

  14. Konstruktion af transducer

    DEFF Research Database (Denmark)

    Henriksen, Lars; Nielsen, Martin Pram

    Formålet med dette midtvejsprojekt er at udarbejde en transducer til måling af pressers stivhed. Dette er gjort på baggrund af en gennemgang af både presse- og stativ-typer samtidig med at udbøjningssituationen beskrives. Der introduceres en ide, der udgør grundkonceptet for opmålingsproceduren o...... færdige transducer – Load cellen. Strain gauge sørger for dataopsamlingen fra load cellen. Disse kalibreres således at transduceren er klar til de videre målinger der ligger i forlængelse af dette projekt....

  15. Retinal functional change caused by adenoviral vector-mediated transfection of LacZ gene.

    Science.gov (United States)

    Sakamoto, T; Ueno, H; Goto, Y; Oshima, Y; Yamanaka, I; Ishibashi, T; Inomata, H

    1998-04-10

    We examined the effect of insertion of an exogenous gene on retinal function to assess the rationale of adenoviral vector-mediated gene transfer for future gene therapy. An adenoviral vector expressing bacterial LacZ (AdCALacZ) was injected into the eyes of adult rats either intravitreally (group A) or subretinally (group B), and the gene expression and retinal function were thus examined at different time points after gene transfer for 3 weeks. X-Gal histostaining showed that neural retinal cells were transfected in group A and that retinal pigment epithelial cells were transfected in group B. The gene transfer was more efficient in group B (54.4% of the fixed retinal area was stained) than in group A (10.4%). The electroretinogram (ERG) revealed retinal dysfunction in the AdCALacZ-transfected rats even at the stage in which the histological damage was not apparent by electron microscopy and immunohistochemical studies for cytokeratin, S-100 protein, and glial fibrillary acidic protein. The ERG change was correlated with the intensity of inflammation, and retinal function recovered to the original level by 3 weeks, along with a diminution of inflammation. Functional changes were more evident in eyes treated with AdCALacZ than in those infected with adenoviral vector with no exogenous gene; however, no histological difference was observed between these groups, indicating that the insertion of exogenous gene itself affects retinal function. The results showed that different kinds of retinal cells could be gene-transferred by an adenoviral vector, depending on the application method. The retinal dysfunction caused by each adenoviral transfection method was caused by inflammation and the insertion of exogenous gene, and this retinal dysfunction was recoverable. In future gene therapy, special attention should be given to the method of exogenous gene insertion in the retina.

  16. A gene expression resource generated by genome-wide lacZ profiling in the mouse

    Directory of Open Access Journals (Sweden)

    Elizabeth Tuck

    2015-11-01

    Full Text Available Knowledge of the expression profile of a gene is a critical piece of information required to build an understanding of the normal and essential functions of that gene and any role it may play in the development or progression of disease. High-throughput, large-scale efforts are on-going internationally to characterise reporter-tagged knockout mouse lines. As part of that effort, we report an open access adult mouse expression resource, in which the expression profile of 424 genes has been assessed in up to 47 different organs, tissues and sub-structures using a lacZ reporter gene. Many specific and informative expression patterns were noted. Expression was most commonly observed in the testis and brain and was most restricted in white adipose tissue and mammary gland. Over half of the assessed genes presented with an absent or localised expression pattern (categorised as 0-10 positive structures. A link between complexity of expression profile and viability of homozygous null animals was observed; inactivation of genes expressed in ≥21 structures was more likely to result in reduced viability by postnatal day 14 compared with more restricted expression profiles. For validation purposes, this mouse expression resource was compared with Bgee, a federated composite of RNA-based expression data sets. Strong agreement was observed, indicating a high degree of specificity in our data. Furthermore, there were 1207 observations of expression of a particular gene in an anatomical structure where Bgee had no data, indicating a large amount of novelty in our data set. Examples of expression data corroborating and extending genotype-phenotype associations and supporting disease gene candidacy are presented to demonstrate the potential of this powerful resource.

  17. Radial derivatives of the mouse ventral pallium traced with Dbx1-LacZ reporters.

    Science.gov (United States)

    Puelles, Luis; Medina, Loreta; Borello, Ugo; Legaz, Isabel; Teissier, Anne; Pierani, Alessandra; Rubenstein, John L R

    2016-09-01

    The progeny of Dbx1-expressing progenitors was studied in the developing mouse pallium, using two transgenic mouse lines: (1) Dbx1(nlslacZ) mice, in which the gene of the β-galactosidase reporter (LacZ) is inserted directly under the control of the Dbx1 promoter, allowing short-term lineage tracing of Dbx1-derived cells; and (2) Dbx1(CRE) mice crossed with a Cre-dependent reporter strain (ROSA26(loxP-stop-loxP-LacZ)), in which the Dbx1-derived cells result permanently labeled (Bielle et al., 2005). We thus examined in detail the derivatives of the postulated longitudinal ventral pallium (VPall) sector, which has been defined among other features by its selective ventricular zone expression of Dbx1 (the recent ascription by Puelles, 2014 of the whole olfactory cortex primordium to the VPall was tested). Earlier notions about a gradiental caudorostral reduction of Dbx1 signal were corroborated, so that virtually no signal was found at the olfactory bulb and the anterior olfactory area. The piriform cortex was increasingly labeled caudalwards. The only endopiriform grisea labeled were the ventral endopiriform nucleus and the bed nucleus of the external capsule. Anterior and basolateral parts of the whole pallial amygdala also were densely marked, in contrast to the negative posterior parts of these pallial amygdalar nuclei (leaving apart medial amygdalar parts ascribed to subpallial or extratelencephalic sources of Dbx1-derived GABAergic and non-GABAergic neurons). Alternative tentative interpretations are discussed to explain the partial labeling obtained of both olfactory and amygdaloid structures. This includes the hypothesis of an as yet undefined part of the pallium, potentially responsible for the posterior amygdala, or the hypothesis that the VPall may not be wholly characterized by Dbx1 expression (this gene not being necessary for VPall molecular distinctness and histogenetic potency), which would leave a dorsal Dbx1-negative VPall subdomain of variable size

  18. Modeling of phased array transducers.

    Science.gov (United States)

    Ahmad, Rais; Kundu, Tribikram; Placko, Dominique

    2005-04-01

    Phased array transducers are multi-element transducers, where different elements are activated with different time delays. The advantage of these transducers is that no mechanical movement of the transducer is needed to scan an object. Focusing and beam steering is obtained simply by adjusting the time delay. In this paper the DPSM (distributed point source method) is used to model the ultrasonic field generated by a phased array transducer and to study the interaction effect when two phased array transducers are placed in a homogeneous fluid. Earlier investigations modeled the acoustic field for conventional transducers where all transducer points are excited simultaneously. In this research, combining the concepts of delayed firing and the DPSM, the phased array transducers are modeled semi-analytically. In addition to the single transducer modeling the ultrasonic fields from two phased array transducers placed face to face in a fluid medium is also modeled to study the interaction effect. The importance of considering the interaction effect in multiple transducer modeling is discussed, pointing out that neighboring transducers not only act as ultrasonic wave generators but also as scatterers.

  19. Curved PVDF airborne transducer.

    Science.gov (United States)

    Wang, H; Toda, M

    1999-01-01

    In the application of airborne ultrasonic ranging measurement, a partially cylindrical (curved) PVDF transducer can effectively couple ultrasound into the air and generate strong sound pressure. Because of its geometrical features, the ultrasound beam angles of a curved PVDF transducer can be unsymmetrical (i.e., broad horizontally and narrow vertically). This feature is desired in some applications. In this work, a curved PVDF air transducer is investigated both theoretically and experimentally. Two resonances were observed in this transducer. They are length extensional mode and flexural bending mode. Surface vibration profiles of these two modes were measured by a laser vibrometer. It was found from the experiment that the surface vibration was not uniform along the curvature direction for both vibration modes. Theoretical calculations based on a model developed in this work confirmed the experimental results. Two displacement peaks were found in the piezoelectric active direction of PVDF film for the length extensional mode; three peaks were found for the flexural bending mode. The observed peak positions were in good agreement with the calculation results. Transient surface displacement measurements revealed that vibration peaks were in phase for the length extensional mode and out of phase for the flexural bending mode. Therefore, the length extensional mode can generate a stronger ultrasound wave than the flexural bending mode. The resonance frequencies and vibration amplitudes of the two modes strongly depend on the structure parameters as well as the material properties. For the transducer design, the theoretical model developed in this work can be used to optimize the ultrasound performance.

  20. Future needs for biomedical transducers

    Science.gov (United States)

    Wooten, F. T.

    1971-01-01

    In summary there are three major classes of transducer improvements required: improvements in existing transducers, needs for unexploited physical science phenomena in transducer design, and needs for unutilized physiological phenomena in transducer design. During the next decade, increasing emphasis will be placed on noninvasive measurement in all of these areas. Patient safety, patient comfort, and the need for efficient utilization of the time of both patient and physician requires that noninvasive methods of monitoring be developed.

  1. Staphylococcus aureus Enterotoxin B Down-Regulates the Expression of Transforming Growth Factor-Beta (TGF-β) Signaling Transducers in Human Glioblastoma.

    Science.gov (United States)

    Akbari, Abolfazl; Farahnejad, Zohreh; Akhtari, Javad; Abastabar, Mahdi; Mobini, Gholam Reza; Mehbod, Amir Seied Ali

    2016-05-01

    It has been revealed that Staphylococcus aureus enterotoxin B (SEB) may feature anti-cancer and anti-metastatic advantages due to its ability to modify cell immunity processes and signaling pathways. Glioblastoma is one of the most aggressive human cancers; it has a high mortality nature, which makes it an attractive area for the development of novel therapies. We examined whether the SEB could exert its growth inhibitory effects on glioblastoma cells partially through the manipulation of a key tumor growth factor termed transforming growth factor-beta (TGF-β). A human primary glioblastoma cell line, U87, was treated with different concentrations of SEB. The cell quantity was measured by the MTT assay at different exposure times. For molecular assessments, total ribonucleic acid (RNA) was extracted from either non-treated or SEB-treated cells. Subsequently, the gene expression of TGF-β transducers, smad2/3, at the messenger RNA (mRNA) level, was analyzed via a quantitative real-time polymerase chain reaction (qPCR) using the SYBR Green method. Significant differences between cell viability and gene expression levels were determined (Prism 5.0 software) using one-way analyses of variance (ANOVA) test. We reported that SEB could effectively down-regulate smad2/3 expression in glioblastoma cells at concentrations as quantity as 1 μg/mL and 2 μg/mL (P < 0.05 and P < 0.01, respectively). The SEB concentrations effective at regulating smad2/3 expression were correlated with those used to inhibit the proliferation of glioblastoma cells. Our results also showed that SEB was able to decrease smad2/3 expression at the mRNA level in a concentration- and time-dependent manner. We suggested that SEB could represent an agent that can significantly decrease smad2/3 expression in glioblastoma cells, leading to moderate TGF-β growth signaling and the reduction of tumor cell proliferation.

  2. Comparison of murine leukemia virus, human immunodeficiency virus, and adeno-associated virus vectors for gene transfer in multiple myeloma: lentiviral vectors demonstrate a striking capacity to transduce low-proliferating primary tumor cells.

    Science.gov (United States)

    De Vos, John; Bagnis, Claude; Bonnafoux, Lydie; Requirand, Guilhem; Jourdan, Michel; Imbert, Marie-Christine; Jourdan, Eric; Rossi, Jean-François; Mannoni, Patrice; Klein, Bernard

    2003-12-10

    Genetic modification of primary tumor cells by gene transfer is of major interest to study the role of specific genes in the biology of a given malignancy and to modify tumor cells for therapeutic use. Multiple myeloma (MM) is a low-proliferating cancer, with often less than 1% of the cells in the S phase of the cell cycle. As primary myeloma cells are notoriously difficult to transduce, we conducted a comparison of various viral vectors, known to integrate the transgene of interest into the target genome, for their ability to stably promote the expression of an enhanced green fluorescent protein (EGFP) transgene. We compared three murine leukemia virus-based vectors, differing only in their viral envelope, a human immunodeficiency virus (HIV)-based vector pseudotyped with the vesicular stomatitis virus glycoprotein (VSV-G), and an adeno-associated virus type 2 vector. Transduction characteristics of these vectors were evaluated in human myeloma cell lines and in primary myeloma cells. Unequivocally, we observed that the VSV-G/HIV vector was the most efficient vector for transducing the cell lines and the only one able to transduce primary myeloma cells reproducibly. The mean percentage of transduced primary myeloma cells was 43.6% (range, 16.3-77.6%), with one round of infection at a low multiplicity of infection, including MM cell samples with less than 1% of cells in the S phase. A quantitative polymerase chain reaction assay demonstrated that this more efficient EGFP expression was associated with a higher GFP copy number in the targeted cell. We propose that lentiviral vectors should be used for transduction of nonproliferating primary tumor cells such as myeloma cells.

  3. Three dimensional transducer

    Science.gov (United States)

    Warren, Oden Lee; Asif, Syed Amanulla Syed; Oh, Yunje; Feng, Yuxin; Cyrankowski, Edward; Major, Ryan

    2014-09-30

    A testing instrument for mechanical testing at nano or micron scale includes a transducer body, and a coupling shaft coupled with a probe tip. A transducer body houses a capacitor. The capacitor includes first and second counter electrodes and a center electrode assembly interposed therebetween. The center electrode assembly is movable with the coupling shaft relative to the first and second counter electrodes, for instance in one or more of dimensions including laterally and normally. The center electrode assembly includes a center plate coupled with the coupling shaft and one or more springs extending from the center plate. Upper and lower plates are coupled with the center plate and cover the center plate and the one or more springs. A shaft support assembly includes one or more support elements coupled along the coupling shaft. The shaft support assembly provides lateral support to the coupling shaft.

  4. Nano-optomechanical transducer

    Science.gov (United States)

    Rakich, Peter T; El-Kady, Ihab F; Olsson, Roy H; Su, Mehmet Fatih; Reinke, Charles; Camacho, Ryan; Wang, Zheng; Davids, Paul

    2013-12-03

    A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.

  5. Three dimensional transducer

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Oden Lee; Asif, Syed Amanulla Syed; Oh, Yunje; Feng, Yuxin; Cyrankowski, Edward; Major, Ryan

    2014-09-30

    A testing instrument for mechanical testing at nano or micron scale includes a transducer body, and a coupling shaft coupled with a probe tip. A transducer body houses a capacitor. The capacitor includes first and second counter electrodes and a center electrode assembly interposed therebetween. The center electrode assembly is movable with the coupling shaft relative to the first and second counter electrodes, for instance in one or more of dimensions including laterally and normally. The center electrode assembly includes a center plate coupled with the coupling shaft and one or more springs extending from the center plate. Upper and lower plates are coupled with the center plate and cover the center plate and the one or more springs. A shaft support assembly includes one or more support elements coupled along the coupling shaft. The shaft support assembly provides lateral support to the coupling shaft.

  6. Numerical transducer modelling

    DEFF Research Database (Denmark)

    Cutanda, Vicente

    1999-01-01

    Numerical modelling is of importance for the design, improvement and study of acoustic transducers such as microphones and accelerometers. Techniques like the boundary element method and the finite element method are the most common supplement to the traditional empirical and analytical approaches...... errors and instabilities in the computations of numerical solutions. An investigation to deal with this narrow-gap problem has been carried out....

  7. Stress wave focusing transducers

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S.R., LLNL

    1998-05-15

    Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

  8. Frequency steerable acoustic transducers

    Science.gov (United States)

    Senesi, Matteo

    Structural health monitoring (SHM) is an active research area devoted to the assessment of the structural integrity of critical components of aerospace, civil and mechanical systems. Guided wave methods have been proposed for SHM of plate-like structures using permanently attached piezoelectric transducers, which generate and sense waves to evaluate the presence of damage. Effective interrogation of structural health is often facilitated by sensors and actuators with the ability to perform electronic, i.e. phased array, scanning. The objective of this research is to design an innovative directional piezoelectric transducer to be employed for the localization of broadband acoustic events, or for the generation of Lamb waves for active interrogation of structural health. The proposed Frequency Steerable Acoustic Transducers (FSATs) are characterized by a spatial arrangement of active material which leads to directional characteristics varying with frequency. Thus FSATs can be employed both for directional sensing and generation of guided waves without relying on phasing and control of a large number of channels. The analytical expression of the shape of the FSATs is obtained through a theoretical formulation for continuously distributed active material as part of a shaped piezoelectric device. The FSAT configurations analyzed in this work are a quadrilateral array and a geometry which corresponds to a spiral in the wavenumber domain. The quadrilateral array is experimentally validated, confirming the concept of frequency-dependent directionality. Its limited directivity is improved by the Wavenumber Spiral FSAT (WS-FSAT), which, instead, is characterized by a continuous frequency dependent directionality. Preliminary validations of the WS-FSAT, using a laser doppler vibrometer, are followed by the implementation of the WS-FSAT as a properly shaped piezo transducer. The prototype is first used for localization of acoustic broadband sources. Signal processing

  9. Fluid force transducer

    Science.gov (United States)

    Jendrzejczyk, Joseph A.

    1982-01-01

    An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

  10. Polymer film composite transducer

    Science.gov (United States)

    Owen, Thomas E.

    2005-09-20

    A composite piezoelectric transducer, whose piezoeletric element is a "ribbon wound" film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.

  11. Steerable Doppler transducer probes

    Energy Technology Data Exchange (ETDEWEB)

    Fidel, H.F.; Greenwood, D.L.

    1986-07-22

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis.

  12. Transducers for ultrasonic limb plethysmography

    Science.gov (United States)

    Nickell, W. T.; Wu, V. C.; Bhagat, P. K.

    1983-01-01

    The design, construction, and performance characteristics of ultasonic transducers suitable for limb plethysmography are presented. Both 3-mm-diameter flat-plate and 12-mm-diameter hemispheric ceramic transducers operating at 2 MHz were fitted in 1-mm thick epoxy-resin lens/acoustic-coupling structures and mounted in exercie-EKG electrode housings for placement on the calf using adhesive collars. The effects of transducer directional characteristics on performance under off-axis rotation and the electrical impedances of the transducers were measured: The flat transducer was found to be sensitive to rotation and have an impedance of 800 ohms; the hemispheric transducer, to be unaffected by rotation and have an impedance of 80 ohms. The use of hemispheric transducers as both transmitter and receiver, or of a flat transducer as transmitter and a hemispheric transducer as receiver, was found to produce adequate dimensional measurements, with minimum care in transducer placement, in short-term physiological experiments and long-term (up to 7-day) attachment tests.

  13. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

  14. Numerical transducer modelling

    DEFF Research Database (Denmark)

    Cutanda, Vicente

    1999-01-01

    Numerical modelling is of importance for the design, improvement and study of acoustic transducers such as microphones and accelerometers. Techniques like the boundary element method and the finite element method are the most common supplement to the traditional empirical and analytical approaches....... However, there are several difficulties to be addressed that are derived from the size, internal structure and precision requirements that are characteristic of these devices. One of them, the presence of very close surfaces (e.g. the microphone diaphragm and back-electrode), leads to machine precision...

  15. Wellbore pressure transducer

    Science.gov (United States)

    Shuck, Lowell Z.

    1979-01-01

    Subterranean earth formations containing energy values are subjected to hydraulic fracturing procedures to enhance the recovery of the energy values. These fractures are induced in the earth formation by pumping liquid into the wellbore penetrating the earth formation until the pressure of the liquid is sufficient to fracture the earth formation adjacent to the wellbore. The present invention is directed to a transducer which is positionable within the wellbore to generate a signal indicative of the fracture initiation useful for providing a timing signal to equipment for seismic mapping of the fracture as it occurs and for providing a measurement of the pressure at which the fracture is initiated.

  16. RADIO-ACTIVE TRANSDUCER

    Science.gov (United States)

    Wanetick, S.

    1962-03-01

    ABS>ure the change in velocity of a moving object. The transducer includes a radioactive source having a collimated beam of radioactive particles, a shield which can block the passage of the radioactive beam, and a scintillation detector to measure the number of radioactive particles in the beam which are not blocked by the shield. The shield is operatively placed across the radioactive beam so that any motion normal to the beam will cause the shield to move in the opposite direction thereby allowing more radioactive particles to reach the detector. The number of particles detected indicates the acceleration. (AEC)

  17. Transducer of linear displacements

    Science.gov (United States)

    Malamed, Y. R.

    1984-02-01

    The basic PLP transducer is designed for a UIM-29 microscope and a 2-coordinate measuring instrument with electronic digital readout. Its optical system consists of an AL-107B light-emitting diode as light source, two condenser lenses, a special wedge carrying two pairs of joined receiver lenses, a prism-mirror, a photoreceiver, a wedge-shape transparent replica of a twin diffraction grating which prevents light reflected by the air-glass interface from focusing on the receiver photodiodes, and a reflective replica of a diffraction grating on a movable carriage. The already available three models of this transducer are PLP1-0.2, PLP1-0.5, and PLP1-1.0 with respectively 625, 250, 125 lines/mm on the transparent replica and respectively 312.5, 125, 62.5 lines/mm on the reflective replica. The scale of moire-interference fringes characterizing the shift between both diffraction gratings per grating period (9.16 mm in each model) is respectively 0.8, 2.0, 4.0 microns and the angle between the two arrays of grating lines on the transparent replica is respectively 36 + or - 4 deg, 90 + or - 10 deg, 190 + or - 20 deg.

  18. Superconducting Qubit Optical Transducer (SQOT)

    Science.gov (United States)

    2015-08-05

    SECURITY CLASSIFICATION OF: The SQOT (Superconducting Qubit Optical Transducer ) project proposes to build a novel electro-optic system which can...Apr-2015 Approved for Public Release; Distribution Unlimited Final Report: "Superconducting Qubit Optical Transducer " (SQOT) The views, opinions and...journals: Number of Papers published in non peer-reviewed journals: Final Report: "Superconducting Qubit Optical Transducer " (SQOT) Report Title The

  19. Miniature multimode monolithic flextensional transducers.

    Science.gov (United States)

    Hladky-Hennion, Anne-Christine; Uzgur, A Erman; Markley, Douglas C; Safari, Ahmad; Cochran, Joe K; Newnham, Robert E

    2007-10-01

    Traditional flextensional transducers classified in seven groups based on their designs have been used extensively in 1-100 kHz range for mine hunting, fish finding, oil explorations, and biomedical applications. In this study, a new family of small, low cost underwater, and biomedical transducers has been developed. After the fabrication of transducers, finite-elements analysis (FEA) was used extensively in order to optimize these miniature versions of high-power, low-frequency flextensional transducer designs to achieve broad bandwidth for both transmitting and receiving, engineered vibration modes, and optimized acoustic directivity patterns. Transducer topologies with various shapes, cross sections, and symmetries can be fabricated through high-volume, low-cost ceramic and metal extrusion processes. Miniaturized transducers posses resonance frequencies in the range of above 1 MHz to below 10 kHz. Symmetry and design of the transducer, polling patterns, driving and receiving electrode geometries, and driving conditions have a strong effect on the vibration modes, resonance frequencies, and radiation patterns. This paper is devoted to small, multimode flextensional transducers with active shells, which combine the advantages of small size and low-cost manufacturing with control of the shape of the acoustic radiation/receive pattern. The performance of the transducers is emphasized.

  20. Addition of TAT protein transduction domain and GrpE to human p53 provides soluble fusion proteins that can be transduced into dendritic cells and elicit p53-specific T-cell responses in HLA-A*0201 transgenic mice

    DEFF Research Database (Denmark)

    Justesen, S; Buus, S; Claesson, M H

    2007-01-01

    in our laboratory were unsuccessful. Here, we show that fusion of an 11-amino-acid region of the human immunodeficiency virus TAT protein transduction domain (PTD) to human p53 increases the solubility of the otherwise insoluble p53 protein and this rTAT-p53 protein can be transduced into human monocyte...

  1. Numerical Transducer Modeling

    DEFF Research Database (Denmark)

    Henriquez, Vicente Cutanda

    This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... tools and implementation techniques are described and performance tests are carried out. The equations that govern the motion of fluids with losses and the corresponding boundary conditions are reduced to a form that is tractable for the Boundary Element Method (BEM) by adopting some hypotheses...... that are allowable in this case: linear variations, absence of flow, harmonic time variation, thermodynamical equilibrium and physical dimensions much larger than the molecular mean free path. A formulation of the BEM is also developed with an improvement designed to cope with the numerical difficulty associated...

  2. Optically transduced MEMS magnetometer

    Science.gov (United States)

    Nielson, Gregory N; Langlois, Eric

    2014-03-18

    MEMS magnetometers with optically transduced resonator displacement are described herein. Improved sensitivity, crosstalk reduction, and extended dynamic range may be achieved with devices including a deflectable resonator suspended from the support, a first grating extending from the support and disposed over the resonator, a pair of drive electrodes to drive an alternating current through the resonator, and a second grating in the resonator overlapping the first grating to form a multi-layer grating having apertures that vary dimensionally in response to deflection occurring as the resonator mechanically resonates in a plane parallel to the first grating in the presence of a magnetic field as a function of the Lorentz force resulting from the alternating current. A plurality of such multi-layer gratings may be disposed across a length of the resonator to provide greater dynamic range and/or accommodate fabrication tolerances.

  3. Electromagnetic acoustic transducer

    Science.gov (United States)

    Alers, George A.; Burns, Jr., Leigh R.; MacLauchlan, Daniel T.

    1988-01-01

    A noncontact ultrasonic transducer for studying the acoustic properties of a metal workpiece includes a generally planar magnetizing coil positioned above the surface of the workpiece, and a generally planar eddy current coil between the magnetizing coil and the workpiece. When a large current is passed through the magnetizing coil, a large magnetic field is applied to the near-surface regions of the workpiece. The eddy current coil can then be operated as a transmitter by passing an alternating current therethrough to excite ultrasonic waves in the surface of the workpiece, or operated as a passive receiver to sense ultrasonic waves in the surface by measuring the output signal. The geometries of the two coils can be varied widely to be effective for different types of ultrasonic waves. The coils are preferably packaged in a housing which does not interfere with their operation, but protects them from a variety of adverse environmental conditions.

  4. Dissemination in athymic nude mice of lacZ transfected small cell lung cancer cells identified by X-gal staining

    DEFF Research Database (Denmark)

    Rømer, M U; Christiansen, J; Brünner, N

    1995-01-01

    The small cell lung cancer cell lines GLC-2 and DMS 456 were genetically labeled with the lacZ gene and examined for invasive and metastatic potential in META/Bom nude mice. The lacZ gene encodes the enzyme beta-D- galactosidase, and cells expressing this enzyme were identified by staining...... with the chromogenic substrate X-gal. lacZ expressing cells were investigated after subcutaneous (s.c.) inoculation and intravenous (i.v.) injection. The X-gal detection of beta-D-galactosidase activity proved to be a rapid and easy means for specific and highly sensitive identification of metastases. All primary s.......c. tumors stained by X-gal. The primary tumors of GLC-2 regularly demonstrated local invasive growth and produced multiple metastases in several organs. In contrast, primary DMS 456 tumors only occasionally demonstrated local invasion and very rarely generated secondary foci. No experimental metastases were...

  5. Inhibition of the growth of human hepatoma cell line both in vitro and in vivo by transducing CKI gene p21WAF-1 with GE7 targeting gene delivery system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The EGF receptor-mediated targeting gene delivery system GE7 was used to transduce exogenous gene pCEP-p21WAF-1 into human hepatocellular carcinoma cell both in vitro and in vivo. After in vitro transduction of the exogenous gene, the growth of the cell lines SMMC-7721 and BEL-7402 was significantly inhibited compared with the control. On day 8 the inhibition rates of the above cell lines reached 56.0% and 66.7%, respectively. The in vivo experiment showed that the growth of human hepatoma transplanted in nude mice injected with GE7 gene delivery system subcutaneously once a week for 3 weeks was remarkably inhibited compared with that of untransfected control. The average tumor weight of the experiment group was (0.083 ± 0.043) g, while that of the control group was (0.281± 0.173) g. The difference is significant (P<0.05). It was indicated that GE7 gene delivery system could efficiently transduce exogenous gene pCEP-p21WAF-1 into hepatoma cell with high EGF receptor expression, and inhibit the cell growth with high efficacy both in vivo and in vitro.

  6. Inhibition of the growth of human hepatoma cell line both in vitro and in vivo by transducing CKI gene p21WAF-1 with GE7 targeting gene delivery system

    Institute of Scientific and Technical Information of China (English)

    韩峻松; 田培坤; 柳湘; 姚明; 顾健人

    2000-01-01

    The EGF receptor-mediated targeting gene delivery system GE7 was used to transduce exogenous gene pCEP-p21WAF-1 into human hepatocellular carcinoma cell both in vitro and in vivo. After in vitro transduction of the exogenous gene, the growth of the cell lines SMMC-7721 and BEL-7402 was significantly inhibited compared with the control. On day 8 the inhibition rates of the above cell lines reached 56.0% and 66.7%, respectively. The in vivo experiment showed that the growth of human hepatoma transplanted in nude mice injected with GE7 gene delivery system subcutaneously once a week for 3 weeks was remarkably inhibited compared with that of untrans-fected control. The average tumor weight of the experiment group was (0.083 ?0.043) g, while that of the control group was (0.28110.173) g. The difference is significant (P<0.05). It was indicated that GE7 gene delivery system could efficiently transduce exogenous gene pCEP-p21WAF-1 into hepatoma cell with high EGF receptor expression, and inhibit the cell growt

  7. Calibration of Underwater Sound Transducers

    Directory of Open Access Journals (Sweden)

    H.R.S. Sastry

    1983-07-01

    Full Text Available The techniques of calibration of underwater sound transducers for farfield, near-field and closed environment conditions are reviewed in this paper .The design of acoustic calibration tank is mentioned. The facilities available at Naval Physical & Oceanographic Laboratory, Cochin for calibration of transducers are also listed.

  8. On a New Optical Transducer

    Directory of Open Access Journals (Sweden)

    Cornel Bit

    2015-07-01

    Full Text Available This paper presents a new type of mechano – optical force transducer which to be used in different mechanical experimental investigations. This transducer has been integrated within a mechanical modulus, providing a useful tool for this kind of measurements. The use of optical methods for the elastic contact measurements has several important advantages.

  9. Simultaneous measurement of benzo[a]pyrene-induced Pig-a and lacZ mutations, micronuclei and DNA adducts in Muta™ Mouse.

    Science.gov (United States)

    Lemieux, Christine L; Douglas, George R; Gingerich, John; Phonethepswath, Souk; Torous, Dorothea K; Dertinger, Stephen D; Phillips, David H; Arlt, Volker M; White, Paul A

    2011-12-01

    In this study we compared the response of the Pig-a gene mutation assay to that of the lacZ transgenic rodent mutation assay, and demonstrated that multiple endpoints can be measured in a 28-day repeat dose study. Muta™Mouse were dosed daily for 28 days with benzo[a]pyrene (BaP; 0, 25, 50 and 75 mg/kg body weight/day) by oral gavage. Micronucleus (MN) frequency was determined in reticulocytes (RETs) 48 hr following the last dose. 72 h following the last dose, mice were euthanized, and tissues (glandular stomach, small intestine, bone marrow and liver) were collected for lacZ mutation and DNA adduct analysis, and blood was evaluated for Pig-a mutants. BaP-derived DNA adducts were detected in all tissues examined and significant dose-dependent increases in mutant Pig-a phenotypes (i.e., RET(CD24-) and RBC (CD24-)) and lacZ mutants were observed. We estimate that mutagenic efficiency (i.e., rate of conversion of adducts into mutations) was much lower for Pig-a compared to lacZ, and speculate that this difference is likely explained by differences in repair capacity between the gene targets, and differences in the cell populations sampled for Pig-a versus lacZ. The BaP doubling doses for both gene targets, however, were comparable, suggesting that similar mechanisms are involved in the accumulation of gene mutations. Significant dose-related increases in % MN were also observed; however, the doubling dose was considerably higher for this endpoint. The similarity in dose response kinetics of Pig-a and lacZ provides further evidence for the mutational origin of glycosylphosphatidylinositol (GPI)-anchor deficiencies detected in the Pig-a assay.

  10. rAAV Vectors as Safe and Efficient Tools for the Stable Delivery of Genes to Primary Human Chondrosarcoma Cells In Vitro and In Situ

    Directory of Open Access Journals (Sweden)

    Henning Madry

    2012-01-01

    Full Text Available Treatment of chondrosarcoma remains a major challenge in orthopaedic oncology. Gene transfer strategies based on recombinant adenoassociated viral (rAAV vectors may provide powerful tools to develop new, efficient therapeutic options against these tumors. In the present study, we tested the hypothesis that rAAV is adapted for a stable and safe delivery of foreign sequences in human chondrosarcoma tissue by transducing primary human chondrosarcoma cells in vitro and in situ with different reporter genes (E. coli lacZ, firefly luc, Discosoma sp. RFP. The effects of rAAV administration upon cell survival and metabolic activities were also evaluated to monitor possibly detrimental effects of the gene transfer method. Remarkably, we provide evidence that efficient and prolonged expression of transgene sequences via rAAV can be safely achieved in all the systems investigated, demonstrating the potential of the approach of direct application of therapeutic gene vectors as a means to treat chondrosarcoma.

  11. Circuit for Driving Piezoelectric Transducers

    Science.gov (United States)

    Randall, David P.; Chapsky, Jacob

    2009-01-01

    The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

  12. Passive wireless ultrasonic transducer systems

    Science.gov (United States)

    Zhong, C. H.; Croxford, A. J.; Wilcox, P. D.

    2014-02-01

    Inductive coupling and capacitive coupling both offer simple solutions to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such system in the context of non-destructive evaluation (NDE) applications. Firstly, the physical principles and construction of an inductively coupled transducer system (ICTS) and a capacitively coupled transducer system (CCTS) are introduced. Then the development of a transmission line model with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate for both systems is described. The models are validated experimentally. Several applications of CCTS are presented, such CCTS for the underwater and through-composite testing.

  13. Fluorescence-activated cell analysis and sorting of viable mammalian cells based on beta-D-galactosidase activity after transduction of Escherichia coli lacZ.

    Science.gov (United States)

    Nolan, G P; Fiering, S; Nicolas, J F; Herzenberg, L A

    1988-01-01

    We demonstrate that individual cells infected with and expressing a recombinant retrovirus carrying the Escherichia coli beta-galactosidase gene (lacZ) can be viably stained, analyzed, sorted, and cloned by fluorescence-activated cell sorting based on the levels of lacZ expressed. To accomplish this we have devised a method to enzymatically generate and maintain fluorescence in live mammalian cells. Accumulation of fluorescent products in cells is linear with time, with a direct correlation of fluorescence to enzymatic activity. This technology for beta-galactosidase detection is more sensitive than other available cytochemical or biochemical methods. We have used this procedure to show that the expression of psi-2-MMuLVSVnlsLacZ in the T-cell lymphoma BW5147 and the B-cell hybridoma SP2/0 is not completely stable and that subclones selected by the fluorescence-activated cell sorter for low lacZ activity demonstrate distinctly lower average expression of LacZ. These findings indicate the utility of beta-galactosidase as a reporter molecule at the single-cell level for studies of gene regulation, including studies of promoter efficacy, enhancer activity, trans-acting factors, and other regulatory elements. Images PMID:3128790

  14. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase II project is to fabricate, characterize, and verify performance of a new type of frequency steered acoustic transducer...

  15. An enzyme logic bioprotonic transducer

    Science.gov (United States)

    Miyake, Takeo; Josberger, Erik E.; Keene, Scott; Deng, Yingxin; Rolandi, Marco

    2015-01-01

    Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdHx electrode as a bioprotonic transducer that connects H+ currents in solution into an electronic signal. This transducer exploits the reversible formation of PdHx in solution according to PdH↔Pd + H+ + e-, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic and gate for glucose and NAD+. PdHx formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output.

  16. Laboratories practice to transducers study

    Directory of Open Access Journals (Sweden)

    Kleber Romero Felizardo

    2004-01-01

    Full Text Available The objective of this work was to gather a collection of practical laboratory experiences , to discover the physical principles of different types of electrical transducers , and to compare them with theoretical models.

  17. Fixture for holding testing transducer

    Science.gov (United States)

    Wagner, Thomas A.; Engel, Herbert P.

    1984-01-01

    A fixture for mounting an ultrasonic transducer against the end of a threaded bolt or stud to test the same for flaws. A base means threadedly secured to the side of the bolt has a rotating ring thereon. A post rising up from the ring (parallel to the axis of the workpiece) pivotally mounts a variable length cross arm, on the inner end of which is mounted the transducer. A spring means acts between the cross arm and the base to apply the testing transducer against the workpiece at a constant pressure. The device maintains constant for successive tests the radial and circumferential positions of the testing transducer and its contact pressure against the end of the workpiece.

  18. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is to develop, fabricate, and characterize a novel frequency steered acoustic transducer (FSAT) for the...

  19. Transducer Field Imaging Using Acoustography

    Directory of Open Access Journals (Sweden)

    Jaswinder S. Sandhu

    2012-01-01

    Full Text Available A common current practice for transducer field mapping is to scan, point-by-point, a hydrophone element in a 2D raster at various distances from the transducer radiating surface. This approach is tedious, requiring hours of scanning time to generate full cross-sectional and/or axial field distributions. Moreover, the lateral resolution of the field distribution image is dependent on the indexing steps between data points. Acoustography is an imaging process in which an acousto-optical (AO area sensor is employed to record the intensity of an ultrasound wavefield on a two-dimensional plane. This paper reports on the application of acoustography as a simple but practical method for assessing transducer field characteristics. A case study performed on a commercial transducer is reported, where the radiated fields are imaged using acoustography and compared to the corresponding quantities that are predicted numerically.

  20. Acoustic transducer with damping means

    Science.gov (United States)

    Smith, Richard W.; Adamson, Gerald E.

    1976-11-02

    An ultrasonic transducer specifically suited to high temperature sodium applications is described. A piezoelectric active element is joined to the transducer faceplate by coating the faceplate and juxtaposed active element face with wetting agents specifically compatible with the bonding procedure employed to achieve the joint. The opposite face of the active element is fitted with a backing member designed to assure continued electrical continuity during adverse operating conditions which can result in the fracturing of the active element. The fit is achieved employing a spring-loaded electrode operably arranged to electrically couple the internal transducer components, enclosed in a hermetically sealed housing, to accessory components normally employed in transducer applications. Two alternative backing members are taught for assuring electrical continuity. The first employs a resilient, discrete multipoint contact electrode in electrical communication with the active element face. The second employs a resilient, elastomeric, electrically conductive, damped member in electrical communication with the active element face in a manner to effect ring-down of the transducer. Each embodiment provides continued electrical continuity within the transducer in the event the active element fractures, while the second provides the added benefit of damping.

  1. Photoacoustic tomography of monkey brain using virtual point ultrasonic transducers.

    Science.gov (United States)

    Nie, Liming; Guo, Zijian; Wang, Lihong V

    2011-07-01

    A photoacoustic tomography system (PAT) using virtual point ultrasonic transducers was developed and applied to image a monkey brain. The custom-built transducers provide a 10-fold greater field-of-view (FOV) than finite-aperture unfocused transducers as well as an improved signal-to-noise ratio (SNR) and reduced artifacts rather than negative-lens transducers. Their tangential resolution, radial resolution, and (SNR) improvements were quantified using tissue phantoms. Our PAT system can achieve high uniformity in both resolution (8) within a large FOV of 6 cm in diameter, even when the imaging objects are enclosed by a monkey skull. The cerebral cortex of a monkey brain was accurately mapped transcranially, through a skull ranging from 2 to 4 mm in thickness. This study demonstrates that PAT can overcome the optical and ultrasound attenuation of a relatively thick skull and can potentially be applied to human neonatal brain imaging.

  2. Two serine residues of non-metastasis protein 23-H1 are critical in inhibiting signal transducer and activator of transcription 3 activity in human lung cancer cells

    Science.gov (United States)

    Wu, Zhihao; Guo, Lili; Ge, Jiangnan; Zhang, Zhijian; Wei, Huijun; Zhou, Qinghua

    2017-01-01

    Constitutive activation of signal transducer and activator of transcription 3 (STAT3) in numerous cancers, including lung cancer, is one of the major mechanisms of tumor progression and metastasis. The authors previously reported that the metastasis suppressor non-metastasis protein 23-H1 (Nm23-H1) negatively regulates STAT3 activity by inhibiting its phosphorylation on Tyr705. Nm23-H1 is a multifunction protein that has three different kinase activities. By transfecting the five mutants that inactivated three different kinase activities respectively into Nm23-H1 deficient lung cancer cell lines, it was identified that Nm23-H1S44A (Ser44 to Ala) and Nm23-H1S120G (Ser120 to Gly) mutant forms were unable to suppress STAT3 phosphorylation on Tyr705, resulting in increased expression of fibronectin and matrix metalloproteinase-9. Notably, protein inhibitor of activated STAT3 was also involved in Nm23-H1S44A- and Nm23-H1S120G-mediated suppression of STAT3 phosphorylation. The present results indicated that Ser44 and Ser120 sites of Nm23-H1 may be responsible for its biological suppressive effects of STAT3 and tumor metastasis, which may contribute to illuminate the metastasis suppression function of Nm23-H1 in lung cancer. PMID:28781685

  3. Characterization of Dielectric Electroactive Polymer transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Møller, Martin B.; Sarban, Rahimullah;

    2014-01-01

    This paper analysis the small-signal model of the Dielectric Electro Active Polymer (DEAP) transducer. The DEAP transducer have been proposed as an alternative to the electrodynamic transducer in sound reproduction systems. In order to understand how the DEAP transducer works, and provide...

  4. Ultrasonic Transducer Irradiation Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmer, Joe [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Keller, Paul [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chien, Hual-Te [Argonne National Lab. (ANL), Argonne, IL (United States); Kohse, Gordon [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Tittmann, Bernhard [Pennsylvania State Univ., University Park, PA (United States); Reinhardt, Brian [Pennsylvania State Univ., University Park, PA (United States); Rempe, Joy [Rempe and Associates, Idaho Falls, ID (United States)

    2015-02-01

    Ultrasonic technologies offer the potential for high-accuracy and -resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other ongoing efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. For this reason, the Pennsylvania State University (PSU) was awarded an ATR NSUF project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The goal of this research is to characterize and demonstrate magnetostrictive and piezoelectric transducer operation during irradiation, enabling the development of novel radiation-tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, one piezoelectric

  5. Endogenous IL-33 is highly expressed in mouse epithelial barrier tissues, lymphoid organs, brain, embryos, and inflamed tissues: in situ analysis using a novel Il-33-LacZ gene trap reporter strain.

    Science.gov (United States)

    Pichery, Mélanie; Mirey, Emilie; Mercier, Pascale; Lefrancais, Emma; Dujardin, Arnaud; Ortega, Nathalie; Girard, Jean-Philippe

    2012-04-01

    IL-33 (previously known as NF from high endothelial venules) is an IL-1 family cytokine that signals through the ST2 receptor and drives cytokine production in mast cells, basophils, eosinophils, invariant NKT and NK cells, Th2 lymphocytes, and type 2 innate immune cells (natural helper cells, nuocytes, and innate helper 2 cells). Little is known about endogenous IL-33; for instance, the cellular sources of IL-33 in mouse tissues have not yet been defined. In this study, we generated an Il-33-LacZ gene trap reporter strain (Il-33(Gt/Gt)) and used this novel tool to analyze expression of endogenous IL-33 in vivo. We found that the Il-33 promoter exhibits constitutive activity in mouse lymphoid organs, epithelial barrier tissues, brain, and embryos. Immunostaining with anti-IL-33 Abs, using Il-33(Gt/Gt) (Il-33-deficient) mice as control, revealed that endogenous IL-33 protein is highly expressed in mouse epithelial barrier tissues, including stratified squamous epithelia from vagina and skin, as well as cuboidal epithelium from lung, stomach, and salivary gland. Constitutive expression of IL-33 was not detected in blood vessels, revealing the existence of species-specific differences between humans and mice. Importantly, IL-33 protein was always localized in the nucleus of producing cells with no evidence for cytoplasmic localization. Finally, strong expression of the Il-33-LacZ reporter was also observed in inflamed tissues, in the liver during LPS-induced endotoxin shock, and in the lung alveoli during papain-induced allergic airway inflammation. Together, our findings support the possibility that IL-33 may function as a nuclear alarmin to alert the innate immune system after injury or infection in epithelial barrier tissues.

  6. Auto-positioning ultrasonic transducer system

    Science.gov (United States)

    Buchanan, Randy K. (Inventor)

    2010-01-01

    An ultrasonic transducer apparatus and process for determining the optimal transducer position for flow measurement along a conduit outer surface. The apparatus includes a transmitting transducer for transmitting an ultrasonic signal, said transducer affixed to a conduit outer surface; a guide rail attached to a receiving transducer for guiding movement of a receiving transducer along the conduit outer surface, wherein the receiving transducer receives an ultrasonic signal from the transmitting transducer and sends a signal to a data acquisition system; and a motor for moving the receiving transducer along the guide rail, wherein the motor is controlled by a controller. The method includes affixing a transmitting transducer to an outer surface of a conduit; moving a receiving transducer on the conduit outer surface, wherein the receiving transducer is moved along a guide rail by a motor; transmitting an ultrasonic signal from the transmitting transducer that is received by the receiving transducer; communicating the signal received by the receiving transducer to a data acquisition and control system; and repeating the moving, transmitting, and communicating along a length of the conduit.

  7. The use of lacZ-transduced tumor cells enhances the sensitivity of micrometastasis detection: A comparative study of gemcitabine treatment efficacy in the mouse LM8 osteosarcoma cell model

    Directory of Open Access Journals (Sweden)

    Arlt MJE

    2014-06-01

    Full Text Available In osteosarcoma patients as well as in preclinical osteosarcoma animal models post-therapy detection of residual disease and of metastases in particular remains a great challenge. The therapeutic efficacy is often overestimated because disseminated tumor cells frequently persist undetectable as dormant micrometastases. This can be avoided in preclinical studies by tagging the tumor cells with reporter genes that allow their selective detection in normal tissue down to the single cell level. In the present study we made use of a lacZ reporter gene and reinvestigated the therapeutic effect of gemcitabine on subcutaneous primary tumor growth and metastasis of mouse LM8 osteosarcoma cells in syngeneic C3H mice. Furthermore we compared the sensitivity of LM8-lacZ and of non-transduced LM8 cells to gemcitabine in vitro and in vivo because it was recently demonstrated that expression of a GFP reporter gene in osteosarcoma cells altered their aggressiveness. The present study showed that, in contrast to previous reports, gemcitabine treatment did not completely eradicate metastasis although it efficiently suppressed the growth of primary tumors and macrometastases. The results also showed that minimal residual disease is not restricted to the lungs, but also occurs in the liver and the kidneys. The direct comparison of the LM8-lacZ with the LM8 cells furthermore demonstrated that constitutive expression of the lacZ reporter gene has no effect on the aggressiveness of the cells or their sensitivity to gemcitabine. The LM8-lacZ cell-derived osteosarcoma mouse model thus represents a highly sensitive and reliable model for evaluation of anticancer drug efficacy in vivo.

  8. Regulation of RAD54- and RAD52-lacZ gene fusions in Saccharomyces cerevisiae in response to DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Cole, G.M.; Schild, D.; Lovett, S.T.; Mortimer, R.K.

    1987-03-01

    The RAD52 and RAD54 genes in the yeast Saccharomyces cerevisiae are involved in both DNA repair and DNA recombination. RAD54 has recently been shown to be inducible by X-rays, while RAD52 is not. To further investigate the regulation of these genes, we constructed gene fusions using 5' regions upstream of the RAD52 and RAD54 genes and a 3'-terminal fragment of the Escherichia coli beta-galactosidase gene. Yeast transformants with either an integrated or an autonomously replicating plasmid containing these fusions expressed beta-galactosidase activity constitutively. In addition, the RAD54 gene fusion was inducible in both haploid and diploid cells in response to the DNA-damaging agents X-rays, UV light, and methyl methanesulfonate, but not in response to heat shock. The RAD52-lacZ gene fusion showed little or no induction in response to X-ray or UV radiation nor methyl methanesulfonate. Typical induction levels for RAD54 in cells exposed to such agents were from 3- to 12-fold, in good agreement with previous mRNA analyses. When MATa cells were arrested in G1 with alpha-factor, RAD54 was still inducible after DNA damage, indicating that the observed induction is independent of the cell cycle. Using a yeast vector containing the EcoRI structural gene fused to the GAL1 promoter, we showed that double-strand breaks alone are sufficient in vivo for induction of RAD54.

  9. Determination of mutational spectrum of the pesticide, captan, with an improved set of Escherichia coli LacZ mutants.

    Science.gov (United States)

    Lu, C; Pfeil, R M; Rice, C P

    1995-07-01

    The mutational spectrum of the fungicide, captan, was determined using a set of improved Escherichia coli lacZ mutants. Captan created mutations mostly at dA-dT sites (83%) with only 17% occurring at dG-dC sites. The hydrolysis products of captan do not appear to be mutagenic because samples of captan at different hydrolysis stages showed basically the same mutational spectra: 31% at AT --> CG transversions, 8% of GC --> AT transitions, 2% of GC --> CG transversions, 8% of GC --> TA transversions, 19% of AT --> TA transversions, and 32% of AT --> GC transitions. Prepared solutions of captan lost their mutational activity gradually over time, indicating that the rate of decrease in mutagenicity agreed with the kinetics of captan hydrolysis reported in other studies. Using the change in mutagenicity to predict degradation, the hydrolysis of captan in pH 7.0 buffer was about three times faster than the hydrolysis carried out in pH 4.5 buffer. To our knowledge, this is the first presentation of mutational spectrum of captan.

  10. Construction of new cloning, lacZ reporter and scarless-markerless suicide vectors for genetic studies in Aggregatibacter actinomycetemcomitans.

    Science.gov (United States)

    Juárez-Rodríguez, María Dolores; Torres-Escobar, Ascención; Demuth, Donald R

    2013-05-01

    To elucidate the putative function of a gene, effective tools are required for genetic characterization that facilitate its inactivation, deletion or modification on the bacterial chromosome. In the present study, the nucleotide sequence of the Escherichia coli/Aggregatibacter actinomycetemcomitans shuttle vector pYGK was determined, allowing us to redesign and construct a new shuttle cloning vector, pJT4, and promoterless lacZ transcriptional/translational fusion plasmids, pJT3 and pJT5. Plasmids pJT4 and pJT5 contain the origin of replication necessary to maintain shuttle vector replication. In addition, a new suicide vector, pJT1, was constructed for the generation of scarless and markerless deletion mutations of genes in the oral pathogen A. actinomycetemcomitans. Plasmid pJT1 is a pUC-based suicide vector that is counter-selectable for sucrose sensitivity. This vector does not leave antibiotic markers or scars on the chromosome after gene deletion and thus provides the option to combine several mutations in the same genetic background. The effectiveness of pJT1 was demonstrated by the construction of A. actinomycetemcomitans isogenic qseB single deletion (ΔqseB) mutant and lsrRK double deletion mutants (ΔlsrRK). These new vectors may offer alternatives for genetic studies in A. actinomycetemcomitans and other members of the HACEK (Haemophilus spp., A. actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) group of Gram-negative bacteria.

  11. Home Automation System Based on Intelligent Transducer Enablers

    Science.gov (United States)

    Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M.; Dapena, Adriana; González-López, Miguel

    2016-01-01

    This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet. PMID:27690031

  12. Home Automation System Based on Intelligent Transducer Enablers.

    Science.gov (United States)

    Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M; Dapena, Adriana; González-López, Miguel

    2016-09-28

    This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

  13. Home Automation System Based on Intelligent Transducer Enablers

    Directory of Open Access Journals (Sweden)

    Manuel Suárez-Albela

    2016-09-01

    Full Text Available This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers, which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

  14. Ultrasound transducer assembly and method for manufacturing an ultrasound transducer assembly

    NARCIS (Netherlands)

    Dekker, R.; Henneken, V.A.; Louwerse, M.C.; Raganato, M.F.

    2015-01-01

    The present invention relates to an ultrasound transducer assembly (10), in particular for intravascular ultrasound systems. The ultrasound transducer assembly comprises at least one silicon substrate element (30) including an ultrasound transducer element (14) for emitting and receiving ultrasound

  15. Ultrasound transducer assembly and method for manufacturing an ultrasound transducer assembly

    NARCIS (Netherlands)

    Dekker, R.; Henneken, V.A.; Louwerse, M.C.; Raganato, M.F.

    2015-01-01

    The present invention relates to an ultrasound transducer assembly (10), in particular for intravascular ultrasound systems. The ultrasound transducer assembly comprises at least one silicon substrate element (30) including an ultrasound transducer element (14) for emitting and receiving ultrasound

  16. Calculations for Piezoelectric Ultrasonic Transducers

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1986-01-01

    Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a boay which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation...... and in particular the finite element method are considered. The finite element method is utilized for analysis of axisymmetric transducers. An explicit, fully piezoelectric, triangular ring element, with linear variations in displacememnt and electric potential is given. The influence of a fluid half-space is also...

  17. Model of a Piezoelectric Transducer

    Science.gov (United States)

    Goodenow, Debra

    2004-01-01

    It's difficult to control liquid and gas in propellant tanks in zero gravity. A possible a design would utilize acoustic liquid manipulation (ALM) technology which uses ultrasonic beams conducted through a liquid and solid media, to push gas bubbles in the liquid to desirable locations. We can propel and control the bubble with acoustic radiation pressure by aiming the acoustic waves on the bubble s surface. This allows us to design a so called smart tank in which the ALM devices transfer the gas to the outer wall of the tank and isolating the liquid in the center. Because the heat transfer rate of a gas is lower of that of the liquid it would substantially decrease boil off and provide of for a longer storage life. The ALM beam is composed of little wavelets which are individual waves that constructively interfere with each other to produce a single, combined acoustic wave front. This is accomplished by using a set of synchronized ultrasound transducers arranged in an array. A slight phase offset of these elements allows us to focus and steer the beam. The device that we are using to produce the acoustic beam is called the piezoelectric transducer. This device converts electrical energy to mechanical energy, which appears in the form of acoustic energy. Therefore the behavior of the device is dependent on both the mechanical characteristics, such as its density, cross-sectional area, and its electrical characteristics, such as, electric flux permittivity and coupling factor. These devices can also be set up in a number of modes which are determined by the way the piezoelectric device is arranged, and the shape of the transducer. For this application we are using the longitudinal or thickness mode for our operation. The transducer also vibrates in the lateral mode, and one of the goals of my project is to decrease the amount of energy lost to the lateral mode. To model the behavior of the transducers I will be using Pspice, electric circuit modeling tool, to

  18. Hemato-endothelial differentiation from lentiviral-transduced human embryonic stem cells retains durable reporter gene expression under the control of ubiquitin promoter

    OpenAIRE

    Jiang, Hua; Lin, Xiaolong; FENG, YOUJI; Xie, Yi; Han, Jinlan; Zhang, Yueping; Wang, Zack Z.; Chen, Tong

    2010-01-01

    Human embryonic stem (hES) cells are able to give rise to a variety of cell lineages under specific culture condition. An effective strategy for stable genetic modification in hES cells may provide a powerful tool for study of human embryogenesis and cell-based therapies. However, gene silences are documented in hES cells. In current study, we investigated whether genes controlled under ubiquitin promoter are expressed during hematopoietic-endothelial differentiation in hES cells. Undifferent...

  19. Non-bonded ultrasonic transducer

    Science.gov (United States)

    Eoff, J.M.

    1984-07-06

    A mechanically assembled non-bonded ultrasonic transducer includes a substrate, a piezoelectric film, a wetting agent, a thin metal electrode, and a lens held in intimate contact by a mechanical clamp. No epoxy or glue is used in the assembly of this device.

  20. Acoustic transducer for acoustic microscopy

    Science.gov (United States)

    Khuri-Yakub, Butrus T.; Chou, Ching H.

    1990-01-01

    A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

  1. Vacuum mounting for piezoelectric transducers

    Science.gov (United States)

    Tiede, D. A.

    1977-01-01

    Special housing couples piezoelectric transducers to nonporous surfaces for ultrasonic or acoustic-emission testing. Device, while providing sound isolation on flat or nonflat surfaces, can be attached and detached quickly. Vacuum sealing mechanism eliminates need for permanent or semipermanent bonds, viscous coupling liquids, weights, magnets, tape, or springs ordinarily used.

  2. Irradiation Testing of Ultrasonic Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua; Tittmann, Bernhard; Reinhardt, Brian; Kohse, Gordon E.; Ramuhalli, Pradeep; Montgomery, Robert O.; Chien, Hual-Te; Villard, Jean-Francois; Palmer, Joe; Rempe, Joy

    2014-07-30

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. For this reason, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2 (E> 0.1 MeV). The goal of this research is to characterize magnetostrictive and piezoelectric transducer survivability during irradiation, enabling the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). As such, this test will be an instrumented lead test and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers.

  3. Wideband Single Crystal Transducer for Bone Characterization

    Science.gov (United States)

    Sahul, Raffi

    2015-01-01

    Phase II objectives: Optimize the Phase I transducer for sensitivity; Test different transmit signals for optimum performance; Demonstrate compatibility with electronics; Confirm additional transducer capabilities over conventional systems by calibrating with other methods.

  4. Transducers and Arrays for Underwater Sound

    CERN Document Server

    Sherman, Charles H

    2007-01-01

    This book is concerned with the theory, development and design of electroacoustic transducers for underwater applications, and is more comprehensive than any existing book in this field. It includes the basics of the six major types of electroacoustic transducers, with emphasis on the piezoelectric ceramic transducers that are currently most widely used. It presents the basic acoustics, as well as specific acoustic data, needed in transducer design and includes analysis of nonlinear effects in transducers. A large number of specific transducer designs, including both projectors and hydrophones, are described in detail as well as methods of modeling, evaluation and measurement. Analysis of transducer arrays, including the effects of mutual radiation impedance, as well as numerical models for transducers and arrays are also covered. The book contains an extensive Appendix of useful current information, including data on the latest transduction materials, and numerous diagrams that will facilitate its use by stu...

  5. A Direct Driver for Electrostatic Transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes a power stage suitable for driving an electrostatic transducer under biasing. Measurement results of a ±400 V prototype amplifier are shown. THD below 1% is reported....

  6. Transducer for harmonic intravascular ultrasound imaging

    NARCIS (Netherlands)

    Vos, Hendrik J.; Frijlink, Martijn E.; Droog, E.J.; Goertz, David E.; Blacquiere, Gerrit; Gisolf, Anton; de Jong, N.; van der Steen, Antonius F.W.

    2005-01-01

    A recent study has shown the feasibility of tissue harmonic imaging (THI) using an intravascular ultrasound (IVUS) transducer. This correspondence describes the design, fabrication, and characterization of a THI-optimized piezoelectric transducer with oval aperture of 0.75 mm by 1 mm. The transducer

  7. 21 CFR 882.1950 - Tremor transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain diseases...

  8. Digital electrostatic acoustic transducer array

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

  9. Self-Calibrating Pressure Transducer

    Science.gov (United States)

    Lueck, Dale E. (Inventor)

    2006-01-01

    A self-calibrating pressure transducer is disclosed. The device uses an embedded zirconia membrane which pumps a determined quantity of oxygen into the device. The associated pressure can be determined, and thus, the transducer pressure readings can be calibrated. The zirconia membrane obtains oxygen .from the surrounding environment when possible. Otherwise, an oxygen reservoir or other source is utilized. In another embodiment, a reversible fuel cell assembly is used to pump oxygen and hydrogen into the system. Since a known amount of gas is pumped across the cell, the pressure produced can be determined, and thus, the device can be calibrated. An isolation valve system is used to allow the device to be calibrated in situ. Calibration is optionally automated so that calibration can be continuously monitored. The device is preferably a fully integrated MEMS device. Since the device can be calibrated without removing it from the process, reductions in costs and down time are realized.

  10. Advanced Geothermal Optical Transducer (AGOT)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-09-01

    Today's geothermal pressure-temperature measuring tools are short endurance, high value instruments, used sparingly because their loss is a major expense. In this project LEL offered to build and test a rugged, affordable, downhole sensor capable ofretuming an uninterrupted data stream at pressures and of 10,000 psi and temperatures up to 250 C, thus permitting continuous deep-well logging. It was proposed to meet the need by specializing LEL's patented 'Twin Column Transducer' technology to satisfy the demands of geothermal pressure/temperature measurements. TCT transducers have very few parts, none of which are moving parts, and all of which can be fabricated from high-temperature super alloys or from ceramics; the result is an extremely rugged device, essentially impervious to chemical attack and readily modified to operate at high pressure and temperature. To measure pressure and temperature they capitalize on the relative expansion of optical elements subjected to thermal or mechanical stresses; if one element is maintained at a reference pressure while the other is opened to ambient, the differential displacement then serves as a measure of pressure. A transducer responding to temperature rather than pressure is neatly created by 'inverting' the pressure-measuring design so that both deflecting structures see identical temperatures and temperature gradients, but whose thermal expansion coefficients are deliberately mismatched to give differential expansion. The starting point for development of a PT Tool was the company's model DPT feedback-stabilized 5,000 psi sensor (U.S. Patent 5,311,014, 'Optical Transducer for Measuring Downhole Pressure', claiming a pressure transducer capable of measuring static, dynamic, and true bi-directional differential pressure at high temperatures), shown in the upper portion of Figure 1. The DPT occupies a 1 x 2 x 4-inch volume, weighs 14 ounces, and is accurate to 1 percent of full

  11. Elongation Transducer For Tensile Tests

    Science.gov (United States)

    Roberts, Paul W.; Stokes, Thomas R.

    1994-01-01

    Extensometer transducer measures elongation of tensile-test specimen with negligible distortion of test results. Used in stress-versus-strain tests of small specimens of composite materials. Clamping stress distributed more evenly. Specimen clamped gently between jaw and facing surface of housing. Friction force of load points on conical tips onto specimen depends on compression of spring, adjusted by turning cover on housing. Limp, light nylon-insulated electrical leads impose minimal extraneous loads on measuring elements.

  12. Covert Channel Synthesis for Transducers

    OpenAIRE

    Benattar, Gilles; Bérard, Béatrice; Lime, Didier; Mullins, John; Roux, Olivier Henri; Sassolas, Mathieu

    2010-01-01

    Research report; Covert channels are a security threat for information systems, since they permit illegal flows, and sometimes leaks, of classified data. Although numerous descriptions have been given at a concrete level, relatively little work has been carried out at a more abstract level, outside probabilistic models. In this paper, we propose a definition of covert channels based on encoding and decoding binary messages with transducers, in a finite transition system. We first compare this...

  13. Micromachined Ultrasonic Transducers for 3-D Imaging

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann

    such transducer arrays, capacitive micromachined ultrasonic transducer (CMUT) technology is chosen for this project. Properties such as high bandwidth and high design flexibility makes this an attractive transducer technology, which is under continuous development in the research community. A theoretical...... of state-of-the-art 3-D ultrasound systems. The focus is on row-column addressed transducer arrays. This previously sparsely investigated addressing scheme offers a highly reduced number of transducer elements, resulting in reduced transducer manufacturing costs and data processing. To produce......Real-time ultrasound imaging is a widely used technique in medical diagnostics. Recently, ultrasound systems offering real-time imaging in 3-D has emerged. However, the high complexity of the transducer probes and the considerable increase in data to be processed compared to conventional 2-D...

  14. Focused ultrasound transducer for thermal treatment.

    Science.gov (United States)

    Umemura, Shin-ichiro

    2015-03-01

    Air-backed transducers have been employed for thermal ultrasonic treatment including both ablation and hyperthermia because the power efficiency rather than the bandwidth is a main concern, unlike a typical imaging transducer working in a pulse mode. The characteristic of an air-backed piezoelectric transducer with a matching layer is analysed, and the role and choice of the matching layer is discussed. An element size of a focused array transducer, appropriate for such thermal treatment, is then estimated, and the characteristic of a piezoceramic transducer element of such a size was numerically analysed using a finite element code. The characteristic of a piezocomposite transducer element is also numerically analysed and its suitability to such a therapeutic array transducer is discussed.

  15. Transducers

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.

    stream_size 27 stream_content_type text/plain stream_name Encycl_Microcomputers_18_335.pdf.txt stream_source_info Encycl_Microcomputers_18_335.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  16. LAVA Pressure Transducer Trade Study

    Science.gov (United States)

    Oltman, Samuel B.

    2016-01-01

    The Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) payload will transport the (LAVA) subsystem to hydrogen-rich locations on the moon supporting NASA's in-situ resource utilization (ISRU) programs. There, the LAVA subsystem will analyze volatiles that evolve from heated regolith samples in order to quantify how much water is present. To do this, the system needs resilient pressure transducers (PTs) to calculate the moles in the gas samples. The PT trade study includes a comparison of newly-procured models to a baseline unit with prior flight history in order to determine the PT model with the best survivability in flight-forward conditions.

  17. Insulin-like growth factor 1 receptor and p38 mitogen-activated protein kinase signals inversely regulate signal transducer and activator of transcription 3 activity to control human dental pulp stem cell quiescence, propagation, and differentiation.

    Science.gov (United States)

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre; Polakowska, Renata

    2014-04-15

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Y(low) stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration.

  18. Double-transduced MDCKII cells to study human P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2) interplay in drug transport across the blood-brain barrier.

    Science.gov (United States)

    Poller, Birk; Wagenaar, Els; Tang, Seng Chuan; Schinkel, Alfred H

    2011-04-04

    P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) combination knockout mice display disproportionately increased brain penetration of shared substrates, including topotecan and several tyrosine kinase inhibitors, compared to mice deficient for only one transporter. To better study the interplay of both transporters also in vitro, we generated a transduced polarized MDCKII cell line stably coexpressing substantial levels of human ABCB1 and ABCG2 (MDCKII-ABCB1/ABCG2). Next, we measured concentration-dependent transepithelial transport of topotecan, sorafenib and sunitinib. By blocking either one or both of the transporters simultaneously, using specific inhibitors, we aimed to mimic the ABCB1-ABCG2 interplay at the blood-brain barrier in wild-type, single or combination knockout mice. ABCB1 and ABCG2 contributed to similar extents to topotecan transport, which was only partly saturable. For sorafenib transport, ABCG2 was the major determinant at low concentrations. However, saturation of ABCG2-mediated transport occurred at higher sorafenib concentrations, where ABCB1 was still fully active. Furthermore, sunitinib was transported equally by ABCB1 and ABCG2 at low concentrations, but ABCG2-mediated transport became saturated at lower concentrations than ABCB1-mediated transport. The relative impact of these transporters can thus be affected by the applied drug concentrations. A comparison of the in vitro observed (inverse) transport ratios and cellular accumulation of the drugs at low concentrations with in vivo brain penetration data from corresponding Abcb1a/1b⁻/⁻, Abcg2⁻/⁻ and Abcb1a/1b;Abcg2⁻/⁻ mouse strains revealed very similar qualitative patterns for each of the tested drugs. MDCKII-ABCB1/ABCG2 cells thus present a useful in vitro model to study the interplay of ABCB1 and ABCG2.

  19. Transducers and arrays for underwater sound

    CERN Document Server

    Butler, John L

    2016-01-01

    This improved and updated second edition covers the theory, development, and design of electro-acoustic transducers for underwater applications. This highly regarded text discusses the basics of piezoelectric and magnetostrictive transducers that are currently being used as well as promising new designs. It presents the basic acoustics as well as the specific acoustics data needed in transducer design and evaluation. A broad range of designs of projectors and hydrophones are described in detail along with methods of modeling, evaluation, and measurement. Analysis of projector and hydrophone transducer arrays, including the effects of mutual radiation impedance and numerical models for elements and arrays, are also covered. The book includes new advances in transducer design and transducer materials and has been completely reorganized to be suitable for use as a textbook, as well as a reference or handbook. The new edition contains updates to the first edition, end-of-chapter exercises, and solutions to select...

  20. Mechanical and electrical characteristics of cymbal transducer

    Institute of Scientific and Technical Information of China (English)

    WANG Guangcan; ZHANG Jin; TIAN Wenjie; LIN Guoguang; LIAN Guandong; ZHANG Fuxue

    2005-01-01

    The electromechanical of Cymbal transducer has been researched. Under simple supporting condition, the mechanical and electrical characteristics have been analyzed by using Piezoelectric-elastic theory, Kirchhoff's thin shell vibration theory, Rayleigh-Ritz's theory and equivalent circuit method. The approximate solution and series resonance frequency equation have been given. Under no load, equivalent circuit, correlation parameters of cymbal transducer and the relations between the ratio of cavity depth to radius of Cymbal transducer with resonance frequency, electromechanical coupling coefficient of cymbal transducer have been researched. The best electromechanical coupling coefficient of cymbal transducer has been gained from the results of numerical analysis. It offers a valid theoretical foundation for optimum design of cymbal transducer.

  1. Analog circuit for controlling acoustic transducer arrays

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas S. (Cedar Crest, NM)

    1991-01-01

    A simplified ananlog circuit is presented for controlling electromechanical transducer pairs in an acoustic telemetry system. The analog circuit of this invention comprises a single electrical resistor which replaces all of the digital components in a known digital circuit. In accordance with this invention, a first transducer in a transducer pair of array is driven in series with the resistor. The voltage drop across this resistor is then amplified and used to drive the second transducer. The voltage drop across the resistor is proportional and in phase with the current to the transducer. This current is approximately 90 degrees out of phase with the driving voltage to the transducer. This phase shift replaces the digital delay required by the digital control circuit of the prior art.

  2. ERROR COMPENSATOR FOR A POSITION TRANSDUCER

    Science.gov (United States)

    Fowler, A.H.

    1962-06-12

    A device is designed for eliminating the effect of leadscrew errors in positioning machines in which linear motion of a slide is effected from rotary motion of a leadscrew. This is accomplished by providing a corrector cam mounted on the slide, a cam follower, and a transducer housing rotatable by the follower to compensate for all the reproducible errors in the transducer signal which can be related to the slide position. The transducer has an inner part which is movable with respect to the transducer housing. The transducer inner part is coupled to the means for rotating the leadscrew such that relative movement between this part and its housing will provide an output signal proportional to the position of the slide. The corrector cam and its follower perform the compensation by changing the angular position of the transducer housing by an amount that is a function of the slide position and the error at that position. (AEC)

  3. Finite State Transducers Approximating Hidden Markov Models

    CERN Document Server

    Kempe, A

    1999-01-01

    This paper describes the conversion of a Hidden Markov Model into a sequential transducer that closely approximates the behavior of the stochastic model. This transformation is especially advantageous for part-of-speech tagging because the resulting transducer can be composed with other transducers that encode correction rules for the most frequent tagging errors. The speed of tagging is also improved. The described methods have been implemented and successfully tested on six languages.

  4. Introduction to Piezoelectric Actuators and Transducers

    Science.gov (United States)

    2007-11-02

    1 Introduction to Piezoelectric Actuators and Transducers Kenji Uchino, International Center for Actuators and Transducers, Penn State University...REPORT DATE 00 JUN 2003 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Introduction to Piezoelectric Actuators and Transducers...now used in various fields. The sound source is made from piezoelectric ceramics as well as magnetostrictive materials. Piezoceramics are generally

  5. Finite Element Modeling for Ultrasonic Transducers (Preprint)

    Science.gov (United States)

    1998-02-27

    virtual prototyping of transducers . Fig. 18 shows a 3D model of a Tonpilz device for low frequency sensing in air. This classical design is usually used...coupled Tonpilz transducer . A thick, flexible matching layer is bonded to the face of the conical head-mass. 7. CONCLUSIONS This paper was intended as a...This is a preprint of a paper published in Proc. SPIE Int. Symp. Medical Imaging 1998, San Diego, Feb 21-27, 1998 Ultrasonic Transducer Engineering

  6. Wideband Single-Crystal Transducer for Bone Characterization

    Science.gov (United States)

    Liang, Yu; Snook, Kevin

    2012-01-01

    The microgravity conditions of space travel result in unique physiological demands on the human body. In particular, the absence of the continual mechanical stresses on the skeletal system that are present on Earth cause the bones to decalcify. Trabecular structure decreases in thickness and increases in spacing, resulting in decreased bone strength and increased risk of injury. Thus, monitoring bone health is a high priority for long-term space travel. A single probe covering all frequency bands of interest would be ideal for such measurements, and this would also minimize storage space and eliminate the complexity of integrating multiple probes. This invention is an ultrasound transducer for the structural characterization of bone. Such characterization measures features of reflected and transmitted ultrasound signals, and correlates these signals with bone structure metrics such as bone mineral density, trabecular spacing, and thickness, etc. The techniques used to determine these various metrics require measurements over a broad range of ultrasound frequencies, and therefore, complete characterization requires the use of several narrowband transducers. This is a single transducer capable of making these measurements in all the required frequency bands. The device achieves this capability through a unique combination of a broadband piezoelectric material; a design incorporating multiple resonator sizes with distinct, overlapping frequency spectra; and a micromachining process for producing the multiple-resonator pattern with common electrode surfaces between the resonators. This device consists of a pattern of resonator bars with common electrodes that is wrapped around a central mandrel such that the radiating faces of the resonators are coplanar and can be simultaneously applied to the sample to be measured. The device operates as both a source and receiver of acoustic energy. It is operated by connection to an electronic system capable of both providing an

  7. Transducers in medical ultrasound: Part Three. Transducer applications in echocardiology.

    Science.gov (United States)

    Lancée, C T; Daigle, R; Sahn, D J; Thijssen, J M

    1985-09-01

    A comparison is made between phased arrays and mechanical sector scanners in transcutaneous echocardiographic applications. Aspects such as contact area, beam control, side lobes, grating lobes and image quality are discussed in the context of transducer frequency. The incorporation of simultaneous acquisition of Doppler velocity information and display of M-mode signals is considered. Transoesophageal and intraoperative scanning systems for cardiology are also compared, in particular linear arrays, phased arrays and mechanical scanners, and their advantages and disadvantages in relation to the above mentioned aspects are discussed. The general conclusion is that electronic sector scanners may have a considerably improved cost/benefit ratio in the near future and thereby will become the leading systems for echocardiography.

  8. Enhancing endosomal escape of transduced proteins by photochemical internalisation.

    Directory of Open Access Journals (Sweden)

    Kevin Mellert

    Full Text Available Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

  9. Linearization of resistance thermometers and other transducers

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1970-01-01

    Given a resistive transducer which responds directly or indirectly to a physical quantity x, it is shown that the relationship may be linearized by linear methods if and only if both the resistance and conductance of the transducer are concave upward as functions of x. This result applies to eith...

  10. 21 CFR 870.2880 - Ultrasonic transducer.

    Science.gov (United States)

    2010-04-01

    ... structures. This device includes phased arrays and two-dimensional scanning transducers. (b) Classification... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic transducer. 870.2880 Section 870.2880...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic...

  11. Characterization of Ultrasonic Transducers. Measurement report

    DEFF Research Database (Denmark)

    Wilhjelm, Jens Erik

    1996-01-01

    This report contains the first results of a field measurement program for characterizing ultrasonic transducers in use at the Department. Specifically, a number of Panametrics Inc, transducers are characterized by using a 0.1 mm point scatterer as target, which is moved in front of the transdcuer....

  12. Pushdown machines for the macro tree transducer

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1986-01-01

    The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree transduc

  13. Micromachined Integrated Transducers for Ultrasound Imaging

    DEFF Research Database (Denmark)

    la Cour, Mette Funding

    The purpose of this project is to develop capacitive micromachined ultrasonic transducers (CMUTs) for medical imaging. Medical ultrasound transducers used today are fabricated using piezoelectric materials and bulk processing. To fabricate transducers capable of delivering a higher imaging...... project and collaboration with a lot of partners to improve medical ultrasound imaging. The focus in this part of the project is to design, fabricate and characterize 1D CMUT arrays. Two versions of 1D transducers are made, one at Stanford University and one at DTU. Electrical and acoustical...... resolution it is however necessary to develop new fabrication methods that allows fabrication of transducer elements with smaller dimensions. By using microfabrication technology it is possible to push the dimensions down and provide higher design flexibility. This project is part of a large ultrasound...

  14. Ultrasound transducer selection in clinical imaging practice.

    Science.gov (United States)

    Szabo, Thomas L; Lewin, Peter A

    2013-04-01

    Many types of medical ultrasound transducers are used in clinical practice. They operate at different center frequencies, have different physical dimensions, footprints, and shapes, and provide different image formats. However, little information is available about which transducers are most appropriate for a given application, and the purpose of this article is to address this deficiency. Specifically, the relationship between the transducer, imaging format, and clinical applications is discussed, and systematic selection criteria that allow matching of transducers to specific clinical needs are presented. These criteria include access to and coverage of the region of interest, maximum scan depth, and coverage of essential diagnostic modes required to optimize a patient's diagnosis. Three comprehensive figures organize and summarize the imaging planes, scanning modes, and types of diagnostic transducers to facilitate their selection in clinical diagnosis.

  15. Role of an expansin-like molecule in Dictyostelium morphogenesis and regulation of its gene expression by the signal transducer and activator of transcription protein Dd-STATa.

    Science.gov (United States)

    Ogasawara, Shun; Shimada, Nao; Kawata, Takefumi

    2009-02-01

    Expansins are proteins involved in plant morphogenesis, exerting their effects on cellulose to extend cell walls. Dictyostelium is an organism that possesses expansin-like molecules, but their functions are not known. In this study, we analyzed the expL7 (expansin-like 7) gene, which has been identified as a putative target of Dd-STATa, a Dictyostelium homolog of the metazoan signal transducer and activator of transcription (STAT) proteins. Promoter fragments of the expL7 were fused to a lacZ reporter and the expression patterns determined. As expected from the behavior of the endogenous expL7 gene, the expL7/lacZ fusion gene was downregulated in Dd-STATa null slugs. In the parental strain, the expL7 promoter was activated in the anterior tip region. Mutational analysis of the promoter identified a sequence that was necessary for expression in tip cells. In addition, an activator sequence for pstAB cells was identified. These sequences act in combination with the repressor region to prevent ectopic expL7 expression in the prespore and prestalk regions of the slug and culminant. Although the expL7 null mutant showed no phenotypic change, the expL7 overexpressor showed aberrant stalk formation. These results indicate that the expansin-like molecule is important for morphogenesis in Dictyostelium.

  16. Glass-windowed ultrasound transducers.

    Science.gov (United States)

    Yddal, Tostein; Gilja, Odd Helge; Cochran, Sandy; Postema, Michiel; Kotopoulis, Spiros

    2016-05-01

    In research and industrial processes, it is increasingly common practice to combine multiple measurement modalities. Nevertheless, experimental tools that allow the co-linear combination of optical and ultrasonic transmission have rarely been reported. The aim of this study was to develop and characterise a water-matched ultrasound transducer architecture using standard components, with a central optical window larger than 10 mm in diameter allowing for optical transmission. The window can be used to place illumination or imaging apparatus such as light guides, miniature cameras, or microscope objectives, simplifying experimental setups. Four design variations of a basic architecture were fabricated and characterised with the objective to assess whether the variations influence the acoustic output. The basic architecture consisted of a piezoelectric ring and a glass disc, with an aluminium casing. The designs differed in piezoelectric element dimensions: inner diameter, ID=10 mm, outer diameter, OD=25 mm, thickness, TH=4 mm or ID=20 mm, OD=40 mm, TH=5 mm; glass disc dimensions OD=20-50 mm, TH=2-4 mm; and details of assembly. The transducers' frequency responses were characterised using electrical impedance spectroscopy and pulse-echo measurements, the acoustic propagation pattern using acoustic pressure field scans, the acoustic power output using radiation force balance measurements, and the acoustic pressure using a needle hydrophone. Depending on the design and piezoelectric element dimensions, the resonance frequency was in the range 350-630 kHz, the -6 dB bandwidth was in the range 87-97%, acoustic output power exceeded 1 W, and acoustic pressure exceeded 1 MPa peak-to-peak. 3D stress simulations were performed to predict the isostatic pressure required to induce material failure and 4D acoustic simulations. The pressure simulations indicated that specific design variations could sustain isostatic pressures up to 4.8 MPa.The acoustic simulations were able to

  17. Electrical modeling of dielectric elastomer stack transducers

    Science.gov (United States)

    Haus, Henry; Matysek, Marc; Moessinger, Holger; Flittner, Klaus; Schlaak, Helmut F.

    2013-04-01

    Performance of dielectric elastomer transducers (DEST) depends on mechanical and electrical parameters. For designing DEST it is therefore necessary to know the influences of these parameters on the overall performance. We show an electrical equivalent circuit valid for a transducer consisting of multiple layers and derive the electrical parameters of the circuit depending on transducers geometry and surface resistivity of the electrodes. This allows describing the DESTs dynamic behavior as a function of fabrication (layout, sheet and interconnection resistance), material (breakdown strength, permittivity) and driving (voltage) parameters. Using this electrical model transfer function and cut-off frequency are calculated, describing the influence of transducer capacitance, resistance and driving frequency on the achievable actuation deflection. Furthermore non ideal boundary effects influencing the capacitance value of the transducer are investigated by an electrostatic simulation and limits for presuming a simple plate capacitor model for calculating the transducer capacitance are derived. Results provide the plate capacitor model is a valid assumption for typical transducer configurations but for certain aspect ratios of electrode dimensions to dielectric thickness -- arising e.g. in the application of tactile interfaces -- the influence of boundary effects is to be considered.

  18. Modeling of functionally graded piezoelectric ultrasonic transducers.

    Science.gov (United States)

    Rubio, Wilfredo Montealegre; Buiochi, Flávio; Adamowski, Julio Cezar; Silva, Emílio Carlos Nelli

    2009-05-01

    The application of functionally graded material (FGM) concept to piezoelectric transducers allows the design of composite transducers without interfaces, due to the continuous change of property values. Thus, large improvements can be achieved, as reduction of stress concentration, increasing of bonding strength, and bandwidth. This work proposes to design and to model FGM piezoelectric transducers and to compare their performance with non-FGM ones. Analytical and finite element (FE) modeling of FGM piezoelectric transducers radiating a plane pressure wave in fluid medium are developed and their results are compared. The ANSYS software is used for the FE modeling. The analytical model is based on FGM-equivalent acoustic transmission-line model, which is implemented using MATLAB software. Two cases are considered: (i) the transducer emits a pressure wave in water and it is composed of a graded piezoceramic disk, and backing and matching layers made of homogeneous materials; (ii) the transducer has no backing and matching layer; in this case, no external load is simulated. Time and frequency pressure responses are obtained through a transient analysis. The material properties are graded along thickness direction. Linear and exponential gradation functions are implemented to illustrate the influence of gradation on the transducer pressure response, electrical impedance, and resonance frequencies.

  19. Seismic transducer modeling using ABAQUS

    Energy Technology Data Exchange (ETDEWEB)

    Stephen R. Novascone

    2004-05-01

    A seismic transducer, known as an orbital vibrator, consists of a rotating imbalance driven by an electric motor. When suspended in a liquid-filled wellbore, vibrations of the device are coupled to the surrounding geologic media. In this mode, an orbital vibrator can be used as an efficient rotating dipole source for seismic imaging. Alternately, the motion of an orbital vibrator is affected by the physical properties of the surrounding media. From this point of view, an orbital vibrator can be used as a stand-alone sensor. The reaction to the surroundings can be sensed and recorded by geophones inside the orbital vibrator. These reactions are a function of the media’s physical properties such as modulus, damping, and density, thereby identifying the rock type. This presentation shows how the orbital vibrator and surroundings were modeled with an ABAQUS acoustic FEM. The FEM is found to compare favorably with theoretical predictions. A 2D FEM and analytical model are compared to an experimental data set. Each model compares favorably with the data set.

  20. Hybrid piezoelectric energy harvesting transducer system

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  1. Piezoelectric pressure transducer technique for oxidizing atmospheres

    Science.gov (United States)

    Roberts, Ted A.; Burton, Rodney L.

    1992-07-01

    The diaphragm sensing tip of a high-speed piezoelectric pressure transducer can be destroyed when measuring transient impulse pressures in hot oxidizing atmospheres, e.g., oxygen at 3000 K and 34 atm for times of tens of milliseconds. A technique is presented to preserve the transducer under these conditions, which uses a protective layer of 0.025-0.050-mm-thick brass foil, held in place with double-sided tape. The integrity of the transducer is preserved, and the response time to a shock wave is increased from 1 to 2-6/microsec using the technique.

  2. Compact Orthomode Transducers Using Digital Polarization Synthesis

    CERN Document Server

    Morgan, Matthew A; Boyd, Tod A

    2010-01-01

    In this paper we present a novel class of compact orthomode transducers which use digital calibration to synthesize the desired polarization vectors while maintaining high isolation and minimizing mass and volume. These digital orthomode transducers consist of an arbitrary number of planar probes in a circular waveguide, each of which is connected to an independent receiver chain designed for stability of complex gain. The outputs of each receiver chain are then digitized and combined numerically with calibrated, complex coefficients. Measurements on two prototype digital orthomode transducers, one with three probes and one with four, show better than 50 dB polarization isolation over a 10 C temperature range with a single calibration.

  3. Comparison between Field Effect Transistors and Bipolar Junction Transistors as Transducers in Electrochemical Sensors

    Science.gov (United States)

    Zafar, Sufi; Lu, Minhua; Jagtiani, Ashish

    2017-01-01

    Field effect transistors (FET) have been widely used as transducers in electrochemical sensors for over 40 years. In this report, a FET transducer is compared with the recently proposed bipolar junction transistor (BJT) transducer. Measurements are performed on two chloride electrochemical sensors that are identical in all details except for the transducer device type. Comparative measurements show that the transducer choice significantly impacts the electrochemical sensor characteristics. Signal to noise ratio is 20 to 2 times greater for the BJT sensor. Sensitivity is also enhanced: BJT sensing signal changes by 10 times per pCl, whereas the FET signal changes by 8 or less times. Also, sensor calibration curves are impacted by the transducer choice. Unlike a FET sensor, the calibration curve of the BJT sensor is independent of applied voltages. Hence, a BJT sensor can make quantitative sensing measurements with minimal calibration requirements, an important characteristic for mobile sensing applications. As a demonstration for mobile applications, these BJT sensors are further investigated by measuring chloride levels in artificial human sweat for potential cystic fibrosis diagnostic use. In summary, the BJT device is demonstrated to be a superior transducer in comparison to a FET in an electrochemical sensor. PMID:28134275

  4. Comparison between Field Effect Transistors and Bipolar Junction Transistors as Transducers in Electrochemical Sensors

    Science.gov (United States)

    Zafar, Sufi; Lu, Minhua; Jagtiani, Ashish

    2017-01-01

    Field effect transistors (FET) have been widely used as transducers in electrochemical sensors for over 40 years. In this report, a FET transducer is compared with the recently proposed bipolar junction transistor (BJT) transducer. Measurements are performed on two chloride electrochemical sensors that are identical in all details except for the transducer device type. Comparative measurements show that the transducer choice significantly impacts the electrochemical sensor characteristics. Signal to noise ratio is 20 to 2 times greater for the BJT sensor. Sensitivity is also enhanced: BJT sensing signal changes by 10 times per pCl, whereas the FET signal changes by 8 or less times. Also, sensor calibration curves are impacted by the transducer choice. Unlike a FET sensor, the calibration curve of the BJT sensor is independent of applied voltages. Hence, a BJT sensor can make quantitative sensing measurements with minimal calibration requirements, an important characteristic for mobile sensing applications. As a demonstration for mobile applications, these BJT sensors are further investigated by measuring chloride levels in artificial human sweat for potential cystic fibrosis diagnostic use. In summary, the BJT device is demonstrated to be a superior transducer in comparison to a FET in an electrochemical sensor.

  5. Portable high precision pressure transducer system

    Science.gov (United States)

    Piper, T. C.; Morgan, J. P.; Marchant, N. J.; Bolton, S. M.

    A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank is presented. Since the response of the pressure transducer is temperature sensitive, it is continually housed in a battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on-board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display.

  6. Conductometric transducers for enzyme-based biosensors.

    Science.gov (United States)

    Mikkelsen, S R; Rechnitz, G A

    1989-08-01

    The use of alternating current conductometric transducers in biosensing devices has been investigated for urea and D-amino acid sensors using the enzyme systems urease and D-amino acid oxidase/catalase. Transducers with copper and platinum electrodes were constructed and characterized, and two enzyme immobilization methods were tested. Detection limits of 1 x 10(-6)M and linear ranges of 2 orders of magnitude were routinely achieved for these model sensors with enzymes covalently immobilized on collagen films.

  7. Performance of Honeywell silicon pressure transducers

    Digital Repository Service at National Institute of Oceanography (India)

    VijayKumar, K.; Joseph, A.; Desai, R.G.P.; Nagvekar, S.; Prabhudesai, S.; Damodaran, V.

    strain gauge, semiconductor strain gauge, and quartz crystal beam. In this paper we examine the laboratory performance of a few temperature-compensated Honeywell silicon strain gauge pressure transducers based on their static calibration. 2. Silicon... Thin-Diaphragm Strain Gauge Pressure Transducer Although semiconductor materials such as germanium and silicon exhibit substantial temperature-dependence, they possess pressure-sensitivities several times that of metallic strain gauges. Silicon...

  8. Piezoelectric and Electrostrictive Materials for Transducer Applications.

    Science.gov (United States)

    1985-05-01

    Structure Ferroelastic Silicates" Alan Hain, Jr. B.S. Engineering Science, May 1984. "New Bimorph Structures with High Flexural Resonance Frequency" Eric ...Applications of PZT/Polymer Composite Materials,’ Ferroelectrics 39, 1245-1248 (1981). 22. Erikson , K.R. ’Tone-Burst Testing of Pulse-Echo Transducer...burst pulse-echo method described by Erikson [2]. A schematic diagram of the experimental set up is shown in Figure 1. The composite transducer was

  9. Design considerations for piezoelectric polymer ultrasound transducers.

    Science.gov (United States)

    Brown, L F

    2000-01-01

    Much work has been published on the design of ultrasound transducers using piezoelectric ceramics, but a great deal of this work does not apply when using the piezoelectric polymers because of their unique electrical and mechanical properties. The purpose of this paper is to review and present new insight into seven important considerations for the design of active piezoelectric polymer ultrasound transducers: piezoelectric polymer materials selection, transducer construction and packaging requirements, materials characterization and modeling, film thickness and active area design, electroding selection, backing material design, and front protection/matching layer design. Besides reviewing these design considerations, this paper also presents new insight into the design of active piezoelectric polymer ultrasonic transducers. The design and fabrication of an immersible ultrasonic transducer, which has no adhesive layer between the active element and backing layer, is included. The transducer features direct deposition of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer onto an insulated aluminum backing substrate. Pulse-echo tests indicated a minimum insertion loss of 37 dB and -6 dB bandwidth of 9.8 to 22 MHz (71%). The use of polymer wear-protection/quarter-wave matching layers is also discussed. Test results on a P(VDF-TrFE) transducer showed that a Mylar/sup TM/ front layer provided a slight increase in pulse-echo amplitude of 15% (or 1.2 dB) and an increase in -6 dB pulse-echo fractional bandwidth from 86 to 95%. Theoretical derivations are reported for optimizing the active area of the piezoelectric polymer element for maximum power transfer at resonance. These derivations are extended to the special case for a low profile (i.e., thin) shielded transducer. A method for modeling the non-linear loading effects of a commercial pulser-receiver is also included.

  10. Wideband Single-Crystal Transducer for Bone Characterization

    Science.gov (United States)

    Liang, Yu; Snook, Kevin

    2012-01-01

    The microgravity conditions of space travel result in unique physiological demands on the human body. In particular, the absence of the continual mechanical stresses on the skeletal system that are present on Earth cause the bones to decalcify. Trabecular structure decreases in thickness and increases in spacing, resulting in decreased bone strength and increased risk of injury. Thus, monitoring bone health is a high priority for long-term space travel. A single probe covering all frequency bands of interest would be ideal for such measurements, and this would also minimize storage space and eliminate the complexity of integrating multiple probes. This invention is an ultrasound transducer for the structural characterization of bone. Such characterization measures features of reflected and transmitted ultrasound signals, and correlates these signals with bone structure metrics such as bone mineral density, trabecular spacing, and thickness, etc. The techniques used to determine these various metrics require measurements over a broad range of ultrasound frequencies, and therefore, complete characterization requires the use of several narrowband transducers. This is a single transducer capable of making these measurements in all the required frequency bands. The device achieves this capability through a unique combination of a broadband piezoelectric material; a design incorporating multiple resonator sizes with distinct, overlapping frequency spectra; and a micromachining process for producing the multiple-resonator pattern with common electrode surfaces between the resonators. This device consists of a pattern of resonator bars with common electrodes that is wrapped around a central mandrel such that the radiating faces of the resonators are coplanar and can be simultaneously applied to the sample to be measured. The device operates as both a source and receiver of acoustic energy. It is operated by connection to an electronic system capable of both providing an

  11. Comparison of piezoresistive and capacitive ultrasonic transducers

    Science.gov (United States)

    Neumann, John J.; Greve, David W.; Oppenheim, Irving J.

    2004-07-01

    MEMS ultrasonic transducers for flaw detection have heretofore been built as capacitive diaphragm-type devices. A diaphragm forms a moveable electrode, placed at a short gap from a stationary electrode, and diaphragm movement has been detected by capacitance change. Although several research teams have successfully demonstrated that technology, the detection of capacitance change is adversely affected by stray and parasitic capacitances, limiting the sensitivity of such transducers and typically requiring relatively large diaphragm areas. We describe the design and fabrication of what to our knowledge is the first CMOS-MEMS ultrasonic phased array transducer using piezoresistive strain sensing. Piezoresistors have been patterned within the diaphragms, and diaphragm movement creates bending strain which is detected by a bridge circuit, for which conductor losses will be less significant. The prospective advantage of such piezoresistive transducers is that sufficient sensitivity may be achieved with very small diaphragms. We compare transducer response under fluid-coupled ultrasonic excitation and report the experimental gauge factor for the piezoresistors. We also discuss the phased array performance of the transducer in sensing the direction of an incoming wave.

  12. Iterative reconstruction of the transducer surface velocity.

    Science.gov (United States)

    Alles, Erwin; van Dongen, Koen

    2013-05-01

    Ultrasound arrays used for medical imaging consist of many elements placed closely together. Ideally, each element vibrates independently. However, because of mechanical coupling, crosstalk between neighboring elements may occur. To quantify the amount of crosstalk, the transducer velocity distribution should be measured. In this work, a method is presented to reconstruct the velocity distribution from far-field pressure field measurements acquired over an arbitrary surface. The distribution is retrieved from the measurements by solving an integral equation, derived from the Rayleigh integral of the first kind, using a conjugate gradient inversion scheme. This approach has the advantages that it allows for arbitrary transducer and pressure field measurement geometries, as well as the application of regularization techniques. Numerical experiments show that measuring the pressure field along a hemisphere enclosing the transducer yields significantly more accurate reconstructions than measuring along a parallel plane. In addition, it is shown that an increase in accuracy is achieved when the assumption is made that all points on the transducer surface vibrate in phase. Finally, the method has been tested on an actual transducer with an active element of 700 × 200 μm which operates at a center frequency of 12.2 MHz. For this transducer, the velocity distribution has been reconstructed accurately to within 50 μm precision from pressure measurements at a distance of 1.98 mm (=16λ0) using a 200-μm-diameter needle hydrophone.

  13. [Inductance transducers for borderline localization of metallic foreign bodies].

    Science.gov (United States)

    Pudov, V I; Reutov, Iu Ia; Korotkikh, S A

    1996-01-01

    The paper outlines the advantages and disadvantages of a ferroprobe inductance transducer used in the borderline localization of a foreign ferromagnetic body. To eliminate the ferroprobe transducer-inherent disadvantages, a whirl-current inductance transducer has been developed. The transducer localizes a foreign nonferromagnetic and ferromagnetic body in its borderline localization in the eye and in the whole body.

  14. 21 CFR 870.2890 - Vessel occlusion transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an electrical..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards). ...

  15. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device... proximal end of the transducer is connected to a pressure monitor that produces an analog or digital...

  16. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Transducer signal amplifier and conditioner. 870... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier and conditioner is a device used to provide the excitation energy for the transducer and to amplify or condition...

  17. 21 CFR 870.2860 - Heart sound transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change in...

  18. Retroviral transfer of the nlsLacZ gene into human CD34+ cell populations and into TF-1 cells: future prospects in gene therapy.

    Science.gov (United States)

    Bagnis, C; Gravis, G; Imbert, A M; Herrera, D; Allario, T; Galindo, R; Lopez, M; Pavon, C; Sempere, C; Mannoni, P

    1994-11-01

    Few data are available concerning behavior of reimplanted human hematopoietic cells after autologous stem cell transplantation. This paper reports the possibility to transfer gene markers coding for beta-galactosidase (beta-Gal) activity by retroviral vectors into a human leukemic growth factor-dependent cell line, TF-1, and into human hematopoietic progenitors isolated from peripheral blood or bone marrow. Using various combinations of retroviral vectors and packaging cell lines, we demonstrated high expression of a bacterial beta-Gal activity induced by the LacZ gene, the nlsLacZ gene, or the Sh-ble/LacZ gene, in human hematopoietic cells. The expression of the nlsLacZ construct was stable until the end of the culture in infected CD34+ cell-enriched cell populations, and a slow decrease of transgene expression was observed in a transduced TF-1 cell population during a 1-year long-term culture. Data obtained with the nlsLacZ gene demonstrate that both retroviral transfer and corresponding gene expression were not found to modify the pattern of cell proliferation and differentiation. These results open interesting prospectives for the use of the nlsLacZ gene to mark and follow the fate of progenitor cells isolated from patients with cancers prior to reimplantation.

  19. Some Strip Contributions to Transducer Design and Analysis

    Science.gov (United States)

    1989-04-28

    19951116 110 14. SUBJECT TERMS Sonar transducers , Tonpilz transducers , ku-mode transducers , 15. NUMBER OF PAGES Piezoelectric ceramic, Ceramic stack...PRACTICAL ILLUSTRATIONS OF THE SGM ANALYSIS ................. 149 B.1 THE IN-WATER SGM RESULTS OF THE STR-330A TONPILZ TRANSDUCER M O D E L...150 B.2 THE IN-WATER SGM RESULTS OF THE STR-330A TONPILZ TRANSDUCER MODEL: VARIABLE mH, FIXED mTAND com

  20. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  1. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

    Full Text Available Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  2. Sequence analysis of lacZ~- mutations induced by ion beam irradiation in double-stranded M13mp18DNA

    Institute of Scientific and Technical Information of China (English)

    杨剑波; 吴李君; 李莉; 吴家道; 余增亮; 许智宏

    1997-01-01

    While M13mpl8 double-stranded DNA was irradiated with ion beam, and transfected into E. coli JM103, a decrease of transfecting activity was discovered. The lacZ-mutation frequency at 20% survival could reach (3.6-16.8) × 104, about 2.3-10 times that of unirradiated M13DNA. Altogether, 27 lacZ~ mutants were select-ed, 10 of which were used for sequencing. 7 of the sequenced mutants show base changes in 250-bp region examined (the remaining 3 mutants probably have base changes outside the regions sequenced). 5 of the base-changed mutants contain more than one mutational base sites (some of them even have 5-6 mutational base sites in 250-bp region ex-amined) ; this dense distribution of base changes in polysites has seldom been seen in X-rays, γ-rays or UV induced DNA mutations. Our experiments also showed that the types of base changes include transitions( 50 % ), transversions (45% ) and deletion (5% ); no addition or duplication was observed. The transitions were mainly C→T and A→G; the transversion

  3. The simulation model of planar electrochemical transducer

    Science.gov (United States)

    Zhevnenko, D. A.; Vergeles, S. S.; Krishtop, T. V.; Tereshonok, D. V.; Gornev, E. S.; Krishtop, V. G.

    2016-12-01

    Planar electrochemical systems are very perspective to build modern motion and pressure sensors. Planar microelectronic technology is successfully used for electrochemical transducer of motion parameters. These systems are characterized by an exceptionally high sensitivity towards mechanic exposure due to high rate of conversion of the mechanic signal to electric current. In this work, we have developed a mathematical model of this planar electrochemical system, which detects the mechanical signals. We simulate the processes of mass and charge transfer in planar electrochemical transducer and calculated its transfer function with different geometrical parameters of the system.

  4. Applications of the Method for Transducer Transient Suppression to Various Transducer Types

    Science.gov (United States)

    1993-08-01

    previously. These types are (i) flexural disk, (ii) Helmholtz resonator, (iii) moving coil, (iv) inductor-tuned Tonpilz , and (v)a dual transducer array of...previously. These types are (i) flexural disk. (ii) Helmholtz resonator, (iii) moving coil, (iv) inductor-tuned Tonpilz , and (v) a dual transducer array of...cycle case, we findV(O -- t-- +i, R (t;>r. even number of half-cycles), (3) FIG. 2. Equivalent circuit for an inductor-tuned Tonpilz transducer . The

  5. An equine herpesvirus 1 mutant with a lacZ insertion between open reading frames 62 and 63 is replication competent and causes disease in the murine respiratory model.

    Science.gov (United States)

    Csellner, H; Walker, C; Love, D N; Whalley, J M

    1998-01-01

    An equine herpesvirus 1 (EHV-1) mutant was constructed by inserting a lacZ expression cassette into the intergenic region upstream of gene 62 (glycoprotein L; gL) and downstream of gene 63 (a homologue of the herpes simplex virus transcriptional activator ICP0). The recombinant lacZ62/63-EHV-1 had similar growth kinetics in cell culture to those of the parental wild type (wt) virus, with indistinguishable cytopathic effects and plaque morphology. Reverse transcriptase PCR confirmed that the lacZ insertion did not interfere with transcription of gL and immunoblot analysis indicated there was no modification to late gene expression as monitored by synthesis of EHV-1 glycoproteins C and D. The parental EHV-1 isolate HVS25A used here had almost identical nucleotide sequence to that published for isolate Ab4, in a 1200 bp region surrounding the insert, but lacked a HindIII site corresponding to Ab4 position 109,048. The lacZ62/63-EHV-1 caused respiratory disease in BALB/c mice with clinical signs, histopathology and virus titres in lungs throughout days 1-5 post infection similar to those induced by wt EHV-1. X-gal staining for beta-galactosidase expression in murine lungs clearly demonstrated EHV-1 infection in cells of the bronchiolar epithelium and pulmonary parenchyma, with a peak of infection evident at day 2 post infection, when up to 50% of bronchioles demonstrated blue-staining and thus virus-infected epithelial cells. The construction of this replication competent virus carrying a reporter gene identifies a site for insertion of foreign genes and will facilitate studies on the pathogenesis of EHV-1.

  6. Transducer-based evaluation of tremor.

    Science.gov (United States)

    Haubenberger, Dietrich; Abbruzzese, Giovanni; Bain, Peter G; Bajaj, Nin; Benito-León, Julián; Bhatia, Kailash P; Deuschl, Günther; Forjaz, Maria João; Hallett, Mark; Louis, Elan D; Lyons, Kelly E; Mestre, Tiago A; Raethjen, Jan; Stamelou, Maria; Tan, Eng-King; Testa, Claudia M; Elble, Rodger J

    2016-09-01

    The International Parkinson and Movement Disorder Society established a task force on tremor that reviewed the use of transducer-based measures in the quantification and characterization of tremor. Studies of accelerometry, electromyography, activity monitoring, gyroscopy, digitizing tablet-based measures, vocal acoustic analysis, and several other transducer-based methods were identified by searching PubMed.gov. The availability, use, acceptability, reliability, validity, and responsiveness were reviewed for each measure using the following criteria: (1) used in the assessment of tremor; (2) used in published studies by people other than the developers; and (3) adequate clinimetric testing. Accelerometry, gyroscopy, electromyography, and digitizing tablet-based measures fulfilled all three criteria. Compared to rating scales, transducers are far more sensitive to changes in tremor amplitude and frequency, but they do not appear to be more capable of detecting a change that exceeds random variability in tremor amplitude (minimum detectable change). The use of transducer-based measures requires careful attention to their limitations and validity in a particular clinical or research setting. © 2016 International Parkinson and Movement Disorder Society.

  7. Broadband, High-Temperature Ultrasonic Transducer

    Science.gov (United States)

    Parker, F. Raymond; Winfree, William P.; Barrows, Danny A.

    1995-01-01

    Materials chosen for endurance at high temperatures and acoustic coupling and damping. Acoustic transducer designed to exhibit broad frequency response and to survive temperatures close to melting points of brazing alloys. Attached directly and continuously to hot object monitored ultrasonically: for example, it can be attached to relatively cool spot on workpiece during brazing for taking ultrasonic quality-control measurements.

  8. Pressure compensated transducer system with constrained diaphragm

    Science.gov (United States)

    Percy, Joseph L.

    1992-08-01

    An acoustic source apparatus has an acoustic transducer that is enclosed in a substantially rigid and watertight enclosure to resist the pressure of water on the transducer and to seal the transducer from the water. The enclosure has an opening through which acoustic signals pass and over which is placed a resilient, expandable and substantially water-impermeable diaphragm. A net stiffens and strengthens the diaphragm as well as constrains the diaphragm from overexpansion or from migrating due to buoyancy forces. Pressurized gas, regulated at slightly above ambient pressure, is supplied to the enclosure and the diaphragm to compensate for underwater ambient pressures. Gas pressure regulated at above ambient pressure is used to selectively tune the pressure levels within the enclosure and diaphragm so that diaphragm resonance can be achieved. Controls are used to selectively fill, as well as vent the enclosure and diaphragm during system descent and ascent, respectively. A signal link is used to activate these controls and to provide the driving force for the acoustic transducer.

  9. An IVUS Transducer for Microbubble Therapies

    Science.gov (United States)

    Kilroy, Joseph P.; Patil, Abhay V.; Rychak, Joshua J.; Hossack, John A.

    2014-01-01

    There is interest in examining the potential of modified intravascular ultrasound (IVUS) catheters to facilitate dual diagnostic and therapeutic roles using ultrasound plus microbubbles for localized drug delivery to the vessel wall. The goal of this study was to design, prototype, and validate an IVUS transducer for microbubble-based drug delivery. A 1-D acoustic radiation force model and finite element analysis guided the design of a 1.5-MHz IVUS transducer. Using the IVUS transducer, biotinylated microbubbles were displaced in water and bovine whole blood to the streptavidin-coated wall of a flow phantom by a 1.5-MHz center frequency, peak negative pressure = 70 kPa pulse with varying pulse repetition frequency (PRF) while monitoring microbubble adhesion with ultrasound. A fit was applied to the RF data to extract a time constant (τ). As PRF was increased in water, the time constant decreased (τ = 32.6 s, 1 kHz vs. τ = 8.2 s, 6 kHz), whereas in bovine whole blood an adhesion–no adhesion transition was found for PRFs ≥ 8 kHz. Finally, a fluorophore was delivered to an ex vivo swine artery using microbubbles and the IVUS transducer, resulting in a 6.6-fold increase in fluorescence. These results indicate the importance of PRF (or duty factor) for IVUS acoustic radiation force microbubble displacement and the potential for IVUS and microbubbles to provide localized drug delivery. PMID:24569249

  10. Eliminating transducer distortion in acoustic measurements

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Torras Rosell, Antoni; McWalter, Richard Ian

    2014-01-01

    This paper investigates the in uence of nonlinear components that contaminate the linear response of acoustic transducer, and presents a method for eliminating the in uence of nonlinearities in acoustic measurements. The method is evaluated on simulated as well as experimental data, and is shown...

  11. Pushdown machines for the macro tree transducer

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1986-01-01

    The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree

  12. Analysis of multifrequency langevin composite ultrasonic transducers.

    Science.gov (United States)

    Lin, Shuyu

    2009-09-01

    The multimode coupled vibration of Langevin composite ultrasonic transducers with conical metal mass of large cross-section is analyzed. The coupled resonance and anti-resonance frequency equations are derived and the effective electromechanical coupling coefficient is analyzed. The effect of the geometrical dimensions on the resonance frequency, the anti-resonance frequency, and the effective electromechanical coupling coefficient is studied. It is illustrated that when the radial dimension is large compared with the longitudinal dimension, the vibration of the Langevin transducer becomes a multifrequency multimode coupled vibration. Numerical methods are used to simulate the coupled vibration; the simulated results are in good agreement with those from the analytical results. Some Langevin transducers of large cross-section are designed and manufactured and their resonance frequencies are measured. It can be seen that the resonance frequencies obtained from the coupled resonance frequency equations are in good agreement with the measured results. It is expected that by properly choosing the dimensions, multifrequency Langevin transducers can be designed and used in ultrasonic cleaning, ultrasonic sonochemistry, and other applications.

  13. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    Science.gov (United States)

    Diaz, Carlos E., Jr.

    2015-01-01

    This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

  14. Piezoelectric micromachined ultrasound transducer (PMUT) arrays for integrated sensing, actuation and imaging

    National Research Council Canada - National Science Library

    Qiu, Yongqiang; Gigliotti, James V; Wallace, Margeaux; Griggio, Flavio; Demore, Christine E M; Cochran, Sandy; Trolier-McKinstry, Susan

    2015-01-01

    .... Piezoelectric micromachined ultrasound transducers (PMUTs), diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays...

  15. Shh pathway in wounds in non-diabetic Shh-Cre-eGFP/Ptch1-LacZ mice treated with MAA beads.

    Science.gov (United States)

    Lisovsky, Alexandra; Sefton, Michael V

    2016-09-01

    Previously, poly(methacrylic acid-co-methyl methacrylate) (MAA) beads were shown to improve vessel formation with a concomitant increase in the expression of the sonic hedgehog (Shh) gene, a pleiotropic factor implicated in vascularization. The aim of this study was to follow up on this observation in the absence of the confounding factors of diabetes in non-diabetic Shh-Cre-eGFP/Ptch1-LacZ mice; in this mouse, expression of GFP and β-Gal is consistent with the transcription patterns of Shh and its receptor patched 1 (Ptch1), respectively. In agreement with studies in diabetic males, MAA beads improved vascularization in large (15 mm × 15 mm) wounds in non-diabetic males at day 7. Shh pathway activation was suggested, as the numbers of GFP+ (Shh) and β-Gal+ (Ptch1, a target of the pathway) cells increased in the granulation tissue. Shh signaling pathway modulation was also suggested in the healthy skin surrounding the wound bed, as evidenced by an increase in the number of GFP+ and β-Gal+ cells in males at day 4. Gene expression analysis of the wounds confirmed increase in Ptch1 and showed the upregulation of a downstream transcription factor Gli3, involved in the vascular effect of the Shh pathway, implicating the pathway in the effect of MAA beads. The efficacy of MAA beads was also investigated in females; MAA beads modulated the Shh pathway within granulation tissue similarly as in males, but had no enhancement effect on the healthy skin and on vascularization. We believe that understanding the molecular and cellular mechanisms of MAA-based biomaterials and testing the efficacy of therapeutics in both sexes will inform the development of novel therapeutic biomaterials.

  16. Evaluation of toxic potential of captan: Induction of hsp70 and tissue damage in transgenic Drosophila melanogaster (hsp70-lacZ) Bg9.

    Science.gov (United States)

    Nazir, Aamir; Mukhopadhyay, Indranil; Saxena, D K; Siddiqui, M Saeed; Chowdhuri, D Kar

    2003-01-01

    The study investigated the working hypothesis that a widely used fungicide captan exerts toxic effects on nontarget organisms. Transgenic Drosophila melanogaster (hsp70-lacZ) was used as a model by assaying stress gene expression as an endpoint for cytotoxicity and also to evaluate whether stress gene expression is sufficient enough to protect and to prevent tissue damage against toxic insult of the chemical. The study was further extended to understand the effect of the pesticide on development, life cycle, and reproduction of the organism and finally to evaluate a concentration of the chemical to be nontoxic to the organism. The study showed that (i) captan causes cytotoxicity at and above 0.015 ppm; (ii) at 0.0015 ppm captan, absence of hsp70 expression in the exposed organism was evaluated as the concentration referred to as no observed adverse effect level (NOAEL) for Drosophila; (iii) emergence pattern of flies was affected only at the highest concentration of captan by 4 days, while hatching and survivorship were unaffected even at this concentration; (iv) reproductive performance was significantly affected only at 125.0 and 1250.0 ppm captan, while in the lower dietary concentrations no such deleterious effects were observed; (v) at 1250.0 ppm, hsp70 failed to protect the cells from toxicant assault after 48 h exposure, thus leading to tissue damage as revealed by Trypan Blue staining. The present study shows the cytotoxic potential of captan and further reveals the application of stress genes in determining NOAEL and its expression as bioindicator of exposure to environmental contaminants.

  17. Effect of Ku80 deficiency on mutation frequencies and spectra at a LacZ reporter locus in mouse tissues and cells.

    Directory of Open Access Journals (Sweden)

    Rita A Busuttil

    Full Text Available Non-homologous end joining (NHEJ is thought to be an important mechanism for preventing the adverse effects of DNA double strand breaks (DSBs and its absence has been associated with premature aging. To investigate the effect of inactivated NHEJ on spontaneous mutation frequencies and spectra in vivo and in cultured cells, we crossed a Ku80-deficient mouse with mice harboring a lacZ-plasmid-based mutation reporter. We analyzed various organs and tissues, as well as cultured embryonic fibroblasts, for mutations at the lacZ locus. When comparing mutant with wild-type mice, we observed a significantly higher number of genome rearrangements in liver and spleen and a significantly lower number of point mutations in liver and brain. The reduced point mutation frequency was not due to a decrease in small deletion mutations thought to be a hallmark of NHEJ, but could be a consequence of increased cellular responses to unrepaired DSBs. Indeed, we found a substantial increase in persistent 53BP1 and gammaH2AX DNA damage foci in Ku80-/- as compared to wild-type liver. Treatment of cultured Ku80-deficient or wild-type embryonic fibroblasts, either proliferating or quiescent, with hydrogen peroxide or bleomycin showed no differences in the number or type of induced genome rearrangements. However, after such treatment, Ku80-deficient cells did show an increased number of persistent DNA damage foci. These results indicate that Ku80-dependent repair of DNA damage is predominantly error-free with the effect of alternative more error-prone pathways creating genome rearrangements only detectable after extended periods of time, i.e., in young adult animals. The observed premature aging likely results from a combination of increased cellular senescence and an increased load of stable, genome rearrangements.

  18. A wideband combined transducer for measuring system in sound tube

    Institute of Scientific and Technical Information of China (English)

    PAN Yaozong; MO Xiping; LIU Yongping; CUI Zheng; ZHANG Tonggen

    2012-01-01

    A wideband transducer for sound tube system is presented, which combines longitudinal transducer and Class IV flextensional transducer to improve the performance at low frequency and broaden the working band. The equivalent circuit is obtained and used to analyze the coupling mechanism between longitudinal transducer and flextensional transducer. A prototype of the transducer is developed after optimizing the electro-acoustic performances by Finite Element Method. The standing wave in the sound tube stimulated by this transducer has been studied and the sound absorbing coefficients of two acoustic materials samples are measured using this sound tube, which shows that the transducer can meet the requirements of acoustic material measurement with the working band ranging from 1.4 kHz to 23 kHz.

  19. Sesamin induces cell cycle arrest and apoptosis through the inhibition of signal transducer and activator of transcription 3 signalling in human hepatocellular carcinoma cell line HepG2.

    Science.gov (United States)

    Deng, Pengyi; Wang, Chen; Chen, Liulin; Wang, Cheng; Du, Yuhan; Yan, Xu; Chen, Mingjie; Yang, Guangxiao; He, Guangyuan

    2013-01-01

    Sesamin, one of the most abundant lignans in sesame seeds, has been shown to exhibit various pharmacological effects. The aim of this study was to elucidate whether sesamin promotes cell cycle arrest and induces apoptosis in HepG2 cells and further to explore the underlying molecular mechanisms. Here, we found that sesamin inhibited HepG2 cell growth by inducing G2/M phase arrest and apoptosis. Furthermore, sesamin suppressed the constitutive and interleukin (IL)-6-induced signal transducer and activator of transcription 3 (STAT3) signalling pathway in HepG2 cells, leading to regulate the downstream genes, including p53, p21, cyclin proteins and the Bcl-2 protein family. Our studies showed that STAT3 signalling played a key role in sesamin-induced G2/M phase arrest and apoptosis in HepG2 cells. These findings provided a molecular basis for understanding of the effects of sesamin in hepatocellular carcinoma tumour cell proliferation. Therefore, sesamin may thus be a potential chemotherapy drug for liver cancer.

  20. Photoacoustic Tomography Imaging of the Adult Zebrafish by Using Unfocused and Focused High-Frequency Ultrasound Transducers

    Directory of Open Access Journals (Sweden)

    Yubin Liu

    2016-11-01

    Full Text Available The zebrafish model provides an essential platform for the study of human diseases or disorders due to the possession of about 87% homologous genes with human. However, it is still very challenging to noninvasively visualize the structure and function of adult zebrafish based on available optical imaging techniques. In this study, photoacoustic tomography (PAT was utilized for high-resolution imaging of adult zebrafish by using focused and unfocused high-frequency (10 MHz ultrasound transducers. We examined and compared the imaging results from the two categories of transducers with in vivo experimental tests, in which we discovered that the unfocused transducer is able to identify the inner organs of adult zebrafish with higher contrast but limited regional resolution, whereas the findings from the focused transducer were with high resolution but limited regional contrast for the recovered inner organs.

  1. Photoacoustic tomography of monkey brain using virtual point ultrasonic transducers

    OpenAIRE

    Nie, Liming; Guo, Zijian; Wang, Lihong V.

    2011-01-01

    A photoacoustic tomography system (PAT) using virtual point ultrasonic transducers was developed and applied to image a monkey brain. The custom-built transducers provide a 10-fold greater field-of-view (FOV) than finite-aperture unfocused transducers as well as an improved signal-to-noise ratio (SNR) and reduced artifacts rather than negative-lens transducers. Their tangential resolution, radial resolution, and (SNR) improvements were quantified using tissue phantoms. Our PAT system can achi...

  2. An ultrasonic--EMG transducer for biodynamic research.

    Science.gov (United States)

    Watkin, K L; Minifie, F D; Kennedy, J G

    1978-03-01

    This note describes a newly developed single-element muscle action potential/motion transducer. The transcuer was specially designed for speech research. Techniques for use of the transducer are described. Sample data are presented illustrating the capability of the transducer, and applications of the device are discussed.

  3. 21 CFR 868.2900 - Gas pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas pressure transducer. 868.2900 Section 868.2900...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2900 Gas pressure transducer. (a) Identification. A gas pressure transducer is a device intended for medical purposes that is used to convert gas...

  4. 21 CFR 868.2885 - Gas flow transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas flow transducer. 868.2885 Section 868.2885...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2885 Gas flow transducer. (a) Identification. A gas flow transducer is a device intended for medical purposes that is used to convert gas flow...

  5. Mechanical properties of mammalian single smooth muscle cells. I. A low cost large range microforce transducer.

    NARCIS (Netherlands)

    J.J. Glerum (Jacobus); R. van Mastrigt (Ron)

    1990-01-01

    textabstractA transducer has been developed for measuring the minute forces generated during isometric contractions (1.0-10.0 microN) of single smooth muscle cells from the pig urinary bladder and the human uterus. In addition to its high sensitivity, resolution and stability (100 mV microN-1, and l

  6. Optomechanical transducers for quantum information processing

    CERN Document Server

    Stannigel, K; Sørensen, A S; Lukin, M D; Zoller, P

    2011-01-01

    We discuss the implementation of optical quantum networks where the interface between stationary and photonic qubits is realized by optomechanical transducers [K. Stannigel et al., PRL 105, 220501 (2010)]. This approach does not rely on the optical properties of the qubit and thereby enables optical quantum communication applications for a wide range of solid-state spin- and charge-based systems. We present an effective description of such networks for many qubits and give a derivation of a state transfer protocol for long-distance quantum communication. We also describe how to mediate local on-chip interactions by means of the optomechanical transducers that can be used for entangling gates. We finally discuss experimental systems for the realization of our proposal.

  7. Electromechanical transducer for acoustic telemetry system

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas S. (Cedar Crest, NM)

    1993-01-01

    An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

  8. Electromechanical transducer for acoustic telemetry system

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, D.S.

    1993-06-22

    An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

  9. New piezoelectric transducers for therapeutic ultrasound.

    Science.gov (United States)

    Chapelon, J Y; Cathignol, D; Cain, C; Ebbini, E; Kluiwstra, J U; Sapozhnikov, O A; Fleury, G; Berriet, R; Chupin, L; Guey, J L

    2000-01-01

    Therapeutic ultrasound (US) has been of increasing interest during the past few years. However, the development of this technique depends on the availability of high-performance transducers. These transducers have to be optimised for focusing and steering high-power ultrasonic energy within the target volume. Recently developed high-power 1-3 piezocomposite materials bring to therapeutic US the exceptional electroacoustical properties of piezocomposite technology: these are high efficiency, large bandwidth, predictable beam pattern, more flexibility in terms of shaping and definition of sampling in annular arrays, linear arrays or matrix arrays. The construction and evaluation of several prototypes illustrates the benefit of this new approach that opens the way to further progress in therapeutic US.

  10. Hybrid neural network models of transducers

    Science.gov (United States)

    Xie, Shilin; Zhang, Xinong; Chen, Shenglai; Zhu, Changchun

    2011-10-01

    A hybrid neural network (NN) approach is proposed and applied to modeling of transducers in the paper. The modeling procedures are also presented in detail. First, the simulated studies on the modeling of single input-single output and multi input-multi output transducers are conducted respectively by use of the developed hybrid NN scheme. Secondly, the hybrid NN modeling approach is utilized to characterize a six-axis force sensor prototype based on the measured data. The results show that the hybrid NN approach can significantly improve modeling precision in comparison with the conventional modeling method. In addition, the method is superior to NN black-box modeling because the former possesses smaller network scale, higher convergence speed, higher model precision and better generalization performance.

  11. Orbital angular momentum-entanglement frequency transducer

    CERN Document Server

    Zhou, Zhi-Yuan; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-01-01

    Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photons orbital angular momentum OAM degrees of freedom is preferred in harnessing the information carrying capacity of a single photon because of its unlimited dimensions. A quantum transducer, which operates at wavelengths from 1558.3 nm to 525 nm for OAM qubits, OAMpolarization hybrid entangled states, and OAM entangled states, is reported for the first time. Nonclassical properties and entanglements are demonstrated following the conversion process by performing quantum tomography, interference, and Bell inequality measurements. Our results demonstrate the capability to create an entanglement link betwe...

  12. Self-Aligned Interdigitated Transducers for Acoustofluidics

    Directory of Open Access Journals (Sweden)

    Zhichao Ma

    2016-11-01

    Full Text Available The surface acoustic wave (SAW is effective for the manipulation of fluids and particles at microscale. The current approach of integrating interdigitated transducers (IDTs for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need for clean room facilities and alignment. The IDTs and microfluidic channels are fabricated using the same process and thus are precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.

  13. Transducer Arrays Suitable for Acoustic Imaging

    Science.gov (United States)

    1978-06-01

    extensional resonance of a thin plate. The stif- fened velocity and acoustic im.pedance of the transducer can be defined then as follows: ,,,D 1/2 󈧥 (3...finite radius performing rotaticnal oscillations about its center. Case (a) is identical to the cne evaluated in this pape-. The integrals in...Poisson’s ratio. For (k.L) > I , the impedance is essen- tially real and oscillates slowly about the longitudinal plane wave impedance. Below (k,L) = 1

  14. Updated Results of Ultrasonic Transducer Irradiation Test

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua; Palmer, Joe [Idaho National Laboratory, P.O. Box 1625, MS 4112, Idaho Falls, ID, 38415-3840 (United States); Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert [Pacific Northwest National Laboratory, 902 Battelle Blvd. Richland, WA, 99354 (United States); Chien, Hual-Te [Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL, 60439 (United States); Tittmann, Bernhard; Reinhardt, Brian [Pennsylvania State University, 212 Earth and Engr. Sciences Building, University Park, PA, 16802 (United States); Kohse, Gordon [Massachusetts Institute of Technology, 77 Massachusetts Ave. Cambridge, MA 02139 (United States); Rempe, Joy [Rempe and Associates, LLC, 360 Stillwater, Idaho Falls, ID 83404 (United States); Villard, J.F. [Commissariat a l' energie atomique et aux energies alternatives, Centre d' etudes de Cadarache, 13108 Saint-Paul-lez-Durance (France)

    2015-07-01

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10{sup 21} n/cm{sup 2}. A multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET-ASI) program also provided initial support for this effort. This irradiation, which started in February 2014, is an instrumented lead test and real-time transducer performance data are collected along with temperature and neutron and gamma flux data. The irradiation is ongoing and will continue to approximately mid-2015. To date, very encouraging results have been attained as several transducers continue to operate under irradiation. (authors)

  15. Transducer Analysis and ATILA++ Model Development

    Science.gov (United States)

    2016-10-10

    the ATILA finite element software package. This will greatly enhance the state-of-the-art in transducer performance prediction and provide a tool...The free dielectric constants for soft crystals show significant change with preload which affects device impedance and amplifier considerations...under Static Preload An apparatus and software control system have been fabricated and developed for evaluating the behavior of materials under high

  16. Characterization of transducer cavities to oscillatory inputs

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.D.; Hollingshead, J.R.

    1993-12-31

    The design and use of measurement systems must ensure that the data are not computed by the measurement system. A wide variety of sources can be responsible for compromising the integrity of test data. Among the sources of error are transducer calibration errors, signal conditioning problems, recording problems, and characteristics of the mechanical system which introduce errors. In this paper, the characteristics of an acoustic cavity are discussed as they apply to a pressure measurement problem.

  17. Lead-Free Intravascular Ultrasound Transducer Using BZT-50BCT Ceramics

    Science.gov (United States)

    Yan, Xingwei; Lam, Kwok Ho; Li, Xiang; Chen, Ruimin; Ren, Wei; Ren, Xiaobing; Zhou, Qifa; Shung, K. Kirk

    2013-01-01

    This paper reports the fabrication and evaluation of a high-frequency ultrasonic transducer based on a new lead-free piezoelectric material for intravascular imaging application. Lead-free 0.5Ba(Zr0.2Ti0.8)O3−0.5(Ba0.7Ca0.3)TiO3 (BZT-50BCT) ceramic with a high dielectric constant (~2800) was employed to develop a high-frequency (~30 MHz) needle-type ultrasonic transducer. With superior piezoelectric performance (piezoelectric coefficient d33 ~ 600 pC/N), the lead-free transducer was found to exhibit a −6-dB bandwidth of 53% with an insertion loss of 18.7 dB. In vitro intravascular ultrasound (IVUS) imaging of a human cadaver coronary artery was performed to demonstrate the potential of the lead-free transducer for biomedical imaging applications. This is the first time that a lead-free transducer has been used for IVUS imaging application. The experimental results suggest that the BZT-50BCT ceramic is a promising lead-free piezoelectric material for high-frequency intravascular imaging applications. PMID:25004492

  18. Micromachined capacitive transducer arrays for intravascular ultrasound

    Science.gov (United States)

    Degertekin, F. Levent; Guldiken, R. Oytun; Karaman, Mustafa

    2005-01-01

    Intravascular ultrasound (IVUS) imaging has become an essential imaging modality for the effective diagnosis and treatment of cardiovascular diseases during the past decade enabled by innovative applications of piezoelectric transducer technology. The limitations in the manufacture and performance of the same piezoelectric transducers have also impeded the improvement of IVUS for emerging clinically important applications such as forward viewing arrays for guiding interventions and high resolution imaging of arterial structure such as vulnerable plaque and fibrous cap, and also implementation of techniques such as harmonic imaging of the tissue and of the contrast agents. Capacitive micromachined ultrasonic transducer (CMUT) technology shows great potential for transforming IVUS not only to satisfy these clinical needs but also to open up possibilities for low-cost imaging devices integrated to therapeutic tools. We have developed manufacturing processes with a maximum process temperature of 250°C to build CMUTs on the same silicon chip with integrated electronics. Using these processes we fabricated CMUT arrays suitable for forward viewing IVUS in the 10-20MHz range. We characterized these array elements in terms of pulse-echo response, radiation pattern measurements and demonstrated its volumetric imaging capabilities on various imaging targets.

  19. Enhanced C-band Coaxial Orthomode Transducer

    Directory of Open Access Journals (Sweden)

    S. I. Piltyay

    2014-09-01

    Full Text Available Introduction. In this paper a novel configuration of wideband coherent coaxial OMT is presented. General Design of an Orthomode Transducer. The OMT consists of elements of 3 main types: a turnstile junction between coaxial quad-ridged waveguide and 4 coaxial transmission lines; 4 coaxial transmission lines of LMR400 type; 2 antiphase power combiners/dividers. A Turnstile Junction Optimization. The optimization of a turnstile junction has been performed. Its minimized reflection coefficient is less than −28 dB in the operation frequency band 3.4–5.4 GHz. A Wideband Antiphase Power Combiner/Divider. The optimization of an antiphase power combiner/divider has been performed. Its minimized reflection coefficient is less than −38 dB. Characteristics of Coaxial Orthomode Transducer Developed. The simulation of OMT characteristics has been performed using CST Design Studio software. Conclusions. A wideband coherent coaxial orthomode transducer has been developed for the operation frequency band 3.4–5.4 GHz. In this frequency band the reflection coefficient of OMT is less than −24 dB and its crosspolar isolation exceeds 38 dB. The wideband coaxial OMT developed can be used in dual-polarized multiband antennas for satellite telecommunications and for radioastronomy.

  20. Stress Sensors and Signal Transducers in Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Sergey Kryazhov

    2010-03-01

    Full Text Available In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks, 12 genes for serine-threonine protein kinases (Spks, 42 genes for response regulators (Rres, seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress.

  1. Cross-fiber Bragg grating transducer

    Science.gov (United States)

    Albin, Sacharia (Inventor); Zheng, Jianli (Inventor); Lavarias, Arnel (Inventor)

    2000-01-01

    A transducer has been invented that uses specially-oriented gratings in waveguide a manner that allows the simultaneous measurement of physical phenomena (such as shear force, strain and temperature) in a single sensing element. The invention has a highly sensitive, linear response and also has directional sensitivity with regard to strain. The transducer has a waveguide with a longitudinal axis as well as two Bragg gratings. The transducer has a first Bragg grating associated with the waveguide that has an angular orientation .theta..sub.a relative to a perpendicular to the longitudinal axis such that 0.degree.<.theta..sub.a <.theta..sub.max. The second Bragg grating is associated with the waveguide in such a way that the angular orientation .theta..sub.b of the grating relative to a perpendicular to the longitudinal axis is (360.degree.-.theta..sub.max)<.theta..sub.b <360.degree.. The first Bragg grating can have a periodicity .LAMBDA..sub.a and the second Bragg grating can have a periodicity .LAMBDA..sub.b such that the periodicity .LAMBDA..sub.a of the first Bragg grating does not equal the periodicity .LAMBDA..sub.b of the second Bragg grating. The angle of the gratings can be such that .theta..sub.a =360.degree.-.theta..sub.b. The waveguide can assume a variety of configurations, including an optical fiber, a rectangular waveguide and a planar waveguide. The waveguide can be fabricated of a variety of materials, including silica and polymer material.

  2. A Neoprene with Optimized Bondability for Sonar Transducer Applications

    Science.gov (United States)

    1987-06-05

    TR-317R TRANSDUCER The TR-317R is a tonpilz transducer mounted in a large spherical array on the front of U.S. Navy submarines of several classes... TRANSDUCER APPLICATIONS TASK NO. 59-0593-0 [SQ-ns«A-n WORK UNIT ACCESSION NO. )N880-326 12. PERSONAL AUTHOR(S) "^ ^Zl!l ^’ ’^’^°"’P"°" ^"i... Transducer Applications tX: C. M. Thompson Materials Section Transducer Branch Underwater Sound Reference Detachment Naval Research Laboratory P.O

  3. Language of Transducer Manipulation: Codifying Terms for Effective Teaching.

    Science.gov (United States)

    Bahner, David P; Blickendorf, J Matthew; Bockbrader, Marcia; Adkins, Eric; Vira, Amar; Boulger, Creagh; Panchal, Ashish R

    2016-01-01

    There is a need for consistent, repetitive, and reliable terminology to describe the basic manipulations of the ultrasound transducer. Previously, 5 basic transducer motions have been defined and used in education. However, even with this effort, there is still a lack of consistency and clarity in describing transducer manipulation and motion. In this technical innovation, we describe an expanded definition of transducer motions, which include movements to change the transducer's angle of insonation to the target as well as the location on the body to optimize the ultrasound image. This new terminology may allow for consistent teaching and improved communication in the process of image acquisition.

  4. The human beta-globin locus control region confers an early embryonic erythroid-specific expression pattern to a basic promoter driving the bacterial lacZ gene

    NARCIS (Netherlands)

    R. Tewari (Rita); N. Gillemans (Nynke); A. Harper; M.G.J.M. Wijgerde (Mark); G. Zafarana (Gaetano); D.D. Drabek (Dubravka); F.G. Grosveld (Frank); J.N.J. Philipsen (Sjaak)

    1996-01-01

    textabstractThe beta-globin locus control region (LCR) is contained on a 20 kb DNA fragment and is characterized by the presence of five DNaseI hypersensitive sites in erythroid cells, termed 5'HS1-5. A fully active 6.5 kb version of the LCR, called the muLCR, has been

  5. Herpes simplex type 1:lacZ recombinant viruses. I. Characterization and application to defining the mechanisms of action of known antiherpes agents.

    Science.gov (United States)

    Dicker, I B; Seetharam, S

    1995-11-01

    Recombinant viruses with the lacZ gene placed under the control of the HSV-1 ICP4, TK and gD regulatory regions were constructed by recombination into the TK locus of HSV-1. Difficulty in isolating ICP4 and gD recombinant viruses with high level, regulated expression of beta-galactosidase was overcome by the use of HSV-1 translational initiation sequences of these genes in place of vector-derived sequences. beta-Galactosidase expression displayed the kinetics particular to each viral class. The maximal expression of beta-galactosidase from the recombinant viruses within a 22-h period (m.o.i. 5) (relative to the ICP4 virus) was gD(3) > gC(2) > ICP4(1) > TK(0.5). The ICP4 virus produces easily quantifiable levels of beta-galactosidase activity for multiplicities of infection from 5 x 10(-4) through 5 over 48 h postinfection. At multiplicities of infection between 2 and 5, ICP4-driven activity was measurable within 2 h postinfection from a monolayer of 3 x 10(4) Vero cells in microtiter wells. Mechanisms of inhibition of several antivirals were probed by using the regulated expression of beta-galactosidase from the ICP4 virus as a marker for viral growth. An experimental antiviral (E3925, IC50 1 microgram/ml) and a neutralizing gD MAb (DUP55306, IC50 0.6 microgram/ml) acted prior to immediate early synthesis, consistent with inhibition of viral entry or uncoating. IFN-gamma inhibited expression of immediate-early synthesis, while having no effect on viral entry. IC50 values for E3925 obtained using either the ICP4 or gD viruses at m.o.i. 0.005, were in good agreement with those obtained by standard plaque assays, but were determined in only 1 day, using a microtiter plate format. Thus, these reporter viruses are useful tools for defining the mechanisms of action of antiherpes agents, while quantitatively reproducing the results for IC50 determinations from standard plaque assays within 24 h in a microtiter plate format.

  6. A quantitative study of methanol/sorbitol co-feeding process of a Pichia pastoris Mut⁺/pAOX1-lacZ strain.

    Science.gov (United States)

    Niu, Hongxing; Jost, Laurent; Pirlot, Nathalie; Sassi, Hosni; Daukandt, Marc; Rodriguez, Christian; Fickers, Patrick

    2013-04-08

    One of the main challenges for heterologous protein production by the methylotrophic yeast Pichia pastoris at large-scale is related to its high oxygen demand. A promising solution is a co-feeding strategy based on a methanol/sorbitol mixture during the induction phase. Nonetheless, a deep understanding of the cellular physiology and the regulation of the AOX1 promoter, used to govern heterologous protein production, during this co-feeding strategy is still scarce. Transient continuous cultures with a dilution rate of 0.023 h(-1) at 25°C were performed to quantitatively assess the benefits of a methanol/sorbitol co-feeding process with a Mut+ strain in which the pAOX1-lacZ construct served as a reporter gene. Cell growth and metabolism, including O2 consumption together with CO2 and heat production were analyzed with regard to a linear change of methanol fraction in the mixed feeding media. In addition, the regulation of the promoter AOX1 was investigated by means of β-galactosidase measurements. Our results demonstrated that the cell-specific oxygen consumption (qO2) could be reduced by decreasing the methanol fraction in the feeding media. More interestingly, maximal β-galactosidase cell-specific activity (>7500 Miller unit) and thus, optimal pAOX1 induction, was achieved and maintained in the range of 0.45 ~ 0.75 C-mol/C-mol of methanol fraction. In addition, the qO2 was reduced by 30% at most in those conditions. Based on a simplified metabolic network, metabolic flux analysis (MFA) was performed to quantify intracellular metabolic flux distributions during the transient continuous cultures, which further shed light on the advantages of methanol/sorbitol co-feeding process. Finally, our observations were further validated in fed-batch cultures. This study brings quantitative insight into the co-feeding process, which provides valuable data for the control of methanol/sorbitol co-feeding, aiming at enhancing biomass and heterologous protein productivities

  7. Parameter sensitivity study of a Field II multilayer transducer model on a convex transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2009-01-01

    .ResultsPredictions using the ZR give a pressure pulse error (PPE) and an intensity error (IE) of 32 % and 23 %, respectively, relative to the measured. Altering the piezoelectric permittivity +12 % from ZR decreases the PPE to 30 % and the IE to 2 % relative to the measured. Changing the stiffness constant of the lens -4......A multilayer transducer model for predicting a transducer impulse response has in earlier works been developed and combined with the Field II software. This development was tested on current, voltage, and intensity measurements on piezoceramics discs (Bæk et al. IUS 2008) and a convex 128 element...... ultrasound imaging transducer (Bæk et al. ICU 2009). The model benefits from its 1D simplicity and hasshown to give an amplitude error around 1.7‐2 dB. However, any prediction of amplitude, phase, and attenuation of pulses relies on the accuracy of manufacturer supplied material characteristics, which may...

  8. Ultrasound transducer function: annual testing is not sufficient.

    Science.gov (United States)

    Mårtensson, Mattias; Olsson, Mats; Brodin, Lars-Åke

    2010-10-01

    The objective was to follow-up the study 'High incidence of defective ultrasound transducers in use in routine clinical practice' and evaluate if annual testing is good enough to reduce the incidence of defective ultrasound transducers in routine clinical practice to an acceptable level. A total of 299 transducers were tested in 13 clinics at five hospitals in the Stockholm area. Approximately 7000-15,000 ultrasound examinations are carried out at these clinics every year. The transducers tested in the study had been tested and classified as fully operational 1 year before and since then been in normal use in the routine clinical practice. The transducers were tested with the Sonora FirstCall Test System. There were 81 (27.1%) defective transducers found; giving a 95% confidence interval ranging from 22.1 to 32.1%. The most common transducer errors were 'delamination' of the ultrasound lens and 'break in the cable' which together constituted 82.7% of all transducer errors found. The highest error rate was found at the radiological clinics with a mean error rate of 36.0%. There was a significant difference in error rate between two observed ways the clinics handled the transducers. There was no significant difference in the error rates of the transducer brands or the transducers models. Annual testing is not sufficient to reduce the incidence of defective ultrasound transducers in routine clinical practice to an acceptable level and it is strongly advisable to create a user routine that minimizes the handling of the transducers.

  9. Safety Issues for HIFU Transducer Design

    Science.gov (United States)

    Fleury, Gérard; Berriet, Rémi; Chapelon, Jean Yves; ter Haar, Gail; Lafon, Cyril; Le Baron, Olivier; Chupin, Laurent; Pichonnat, Fabrice; Lenormand, Jérôme

    2005-03-01

    In contrast with most ultrasound modalities for medical applications, (especially ultrasound imaging), High Intensity Focused Ultrasound (HIFU) involves technologies and procedures which may present risk to the patient. These risks, resulting from the high power levels required for effective therapy, should be taken into account at the earliest stages in the design of a system dedicated to HIFU treatment. An understanding of these risks must thus be shared amongst the many players in the field of therapy using high power ultrasound. Moreover, since the number of applications of HIFU has increased appreciably over recent years and the technology is ready to move from the research to the industrial level, it is worth now considering solutions that should be put in place to guarantee the safety of the patient during HIFU treatment. This paper reports thoughts on this, identifies some risks to the patient that must be taken into consideration in the design of HIFU transducers, and proposes some solutions that could prevent the deleterious consequences of transducer misuse or failure. For the main risks identified, such as exceeding the desired acoustic power or poor control of tissue targeting, a description of transducer performance that could potentially result in problems is systematically sought. This allows proposals for precautions to be taken during operation to be made. Parameters which should be monitored to ensure safe use are also suggested. This type of approach, which should be undertaken for the different components of a therapeutic system, highlights the challenges that must be faced in the immediate future for the development and safe exploitation of HIFU systems. The necessity for standard definitions of the parameters to be checked or monitored during HIFU treatments is crucial in this approach, as is the availability of reliable dedicated measurement devices. Co-ordinated action on these topics in the HIFU community would contribute to the

  10. Dynamics of receptor and protein transducer homodimerisation

    Directory of Open Access Journals (Sweden)

    Kolch Walter

    2008-10-01

    Full Text Available Abstract Background Signalling pathways are complex systems in which not only simple monomeric molecules interact, but also more complex structures that include constitutive or induced protein assemblies. In particular, the hetero-and homo-dimerisation of proteins is a commonly encountered motif in signalling pathways. Several authors have suggested in recent times that dimerisation relates to a series of physical and biological outcomes used by the cell in the regulation of signal transduction. Results In this paper we investigate the role of homodimerisation in receptor-protein transducer interactions. Towards this end, mathematical modelling is used to analyse the features of such kind of interactions and to predict the behaviour of the system under different experimental conditions. A kinetic model in which the interaction between homodimers provokes a dual mechanism of activation (single and double protein transducer activation at the same time is proposed. In addition, we analyse under which conditions the use of a power-law representation for the system is useful. Furthermore, we investigate the dynamical consequences of this dual mechanism and compare the performance of the system in different simulated experimental conditions. Conclusion The analysis of our mathematical model suggests that in receptor-protein interacting systems with dual mechanism there may be a shift between double and single activation in a way that intense double protein transducer activation could initiate and dominate the signal in the short term (getting a fast intense signal, while single protein activation could control the system in the medium and long term (when input signal is weaker and decreases slowly. Our investigation suggests that homodimerisation and oligomerisation are mechanisms used to enhance and regulate the dynamic properties of the initial steps in signalling pathways.

  11. A Hail Size Distribution Impact Transducer

    CERN Document Server

    Lane, John E; Haskell, William D; Cox, Robert B

    2014-01-01

    An active impact transducer has been designed and tested for the purpose of monitoring hail fall in the vicinity of the Space Shuttle launch pads. An important outcome of this design is the opportunity to utilize frequency analysis to discriminate between the audio signal generated from raindrop impacts and that of hailstone impacts. The sound of hail impacting a metal plate is sub-tly but distinctly different than the sound of rain impacts. This useful characteristic permits application of signal processing algorithms that are inherently more robust than techniques relying on amplitude processing alone in the implementation of a hail disdrometer.

  12. Transduced monocyte/macrophages targeted to murine skin by UV light.

    Science.gov (United States)

    Zhang, Alexandra Y; Wu, Caiyun; Zhou, Lixin; Ismail, Sahar A; Tao, Jianming; McCormick, Laura L; Cooper, Kevin D; Gilliam, Anita C

    2006-01-01

    We have selectively targeted monocyte/macrophages overexpressing an immunomodulatory molecule, latency-associated peptide (LAP), a naturally occurring antagonist for transforming growth factor-beta1, to murine skin utilizing UV light to produce a cutaneous influx of transduced monocyte/macrophages. Bone marrow (BM) cells from BALB/c mice were transduced in vitro with a retroviral construct containing green fluorescent protein (GFP) for detection and human LAP (hLAP) as a test molecule. The transduced BM cells were then cultured in vitro with granulocyte-macrophage colony-stimulating factor (GM-CSF) to produce differentiation to monocyte/macrophages. More than 80% of transduced BM cells were CD11b-positive and MOMA-positive by fluorescence-activated cell-sorter analysis and secreted LAP by ELISA after 10 days of culture in granulocyte-macrophage colony-stimulating factor (GM-CSF). Transduced monocyte/macrophages containing either GFP or hLAP-GFP were then injected intravenously into BALB/c mice. One-half of recipients in each group were exposed to UVB (72 mJ) to induce monocyte/macrophage infiltration into skin. Recipients were sacrificed 60 h after UV irradiation. We found transduced cutaneous macrophages expressing GFP by examining with fluorescence microscopy frozen skin sections of recipient mice immunostained with antibodies to GFP and to macrophage marker F4/80. We identified hLAP sequences by polymerase chain reaction (PCR) of total DNA in recipient blood and UV-irradiated skin but not in unirradiated skin. LAP sequences were also detected at much lower levels in other organs (lung, spleen, and liver) by PCR. Therefore, we have shown that genetically altered monocytic cells can be injected intravenously and targeted to mouse skin by UV exposure. This macrophage-based gene-transfer method may be a potentially useful immunotherapeutic approach for delivering monocyte/macrophage-derived products to skin.

  13. Optimization of matching layer design for medical ultrasonic transducer

    Science.gov (United States)

    Zhu, Jie

    This thesis work contains two major parts. In the first part, ultrasonic wave propagation in multilayer structure is investigated. Delaminations between ceramic and electrode layers in multilayer capacitors and multilayer actuators are common defects, which are difficult to detect using traditional ultrasonic imaging method if the size is smaller than 50 microns in diameter. The T-Matrix method is used to treat wave attenuation in periodic structures with alternating ceramic and electrode layers. Multiple penny-shaped delaminations are assumed perpendicular to the incidence wave, and the forward scattering amplitude of the wave from delaminations is calculated by substituting the average effective crack opening displacement into the scattered wave displacement. The effective phase velocity, wave amplitude and the attenuation coefficient have been calculated for different crack densities. The results provide a theoretical base for potential attenuation based ultrasonic non-destructive evaluation (NDE) method. The second part is a study on matching layers. Matching layers are crucial components in ultrasonic transducers for medical imaging. Without proper matching layers, large acoustic impedance mismatch between piezoelectric resonator and the human body tissue will cause most of the ultrasound energy to be reflected at the interface. For a given frequency, the matching layer thickness should be one quarter of the wavelength and its acoustic impedance should be the geometric mean of the acoustic impedances of piezoelectric material and the imaging body. There are no natural materials that can precisely meet such requirements. Therefore, solid particle/polymer composites are commonly used as matching layer materials. The acoustic impedance of such composites is generally in the range of 2-15 MRayls. It is a routine task to make such composite for low frequency transducers, but for transducers with operating frequency higher than 40 MHz, the powder size must be sub

  14. Floating Ultrasonic Transducer Inspection System and Method for Nondestructive Evaluation

    Science.gov (United States)

    Zalameda, Joseph N. (Inventor); Johnston, Patrick H. (Inventor)

    2016-01-01

    A method for inspecting a structural sample using ultrasonic energy includes positioning an ultrasonic transducer adjacent to a surface of the sample, and then transmitting ultrasonic energy into the sample. Force pulses are applied to the transducer concurrently with transmission of the ultrasonic energy. A host machine processes ultrasonic return pulses from an ultrasonic pulser/receiver to quantify attenuation of the ultrasonic energy within the sample. The host machine detects a defect in the sample using the quantified level of attenuation. The method may include positioning a dry couplant between an ultrasonic transducer and the surface. A system includes an actuator, an ultrasonic transducer, a dry couplant between the transducer the sample, a scanning device that moves the actuator and transducer, and a measurement system having a pulsed actuator power supply, an ultrasonic pulser/receiver, and a host machine that executes the above method.

  15. Orbital Angular Momentum-Entanglement Frequency Transducer

    Science.gov (United States)

    Zhou, Zhi-Yuan; Liu, Shi-Long; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-09-01

    Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology, and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photon's orbital angular momentum (OAM) degrees of freedom is preferred in harnessing the information-carrying capacity of a single photon because of its unlimited dimensions. A quantum transducer, which operates at wavelengths from 1558.3 to 525 nm for OAM qubits, OAM-polarization hybrid-entangled states, and OAM-entangled states, is reported for the first time. Nonclassical properties and entanglements are demonstrated following the conversion process by performing quantum tomography, interference, and Bell inequality measurements. Our results demonstrate the capability to create an entanglement link between different quantum systems operating in a photon's OAM degrees of freedom, which will be of great importance in building a high-capacity OAM quantum network.

  16. Instantaneous crack detection using dual PZT transducers

    Science.gov (United States)

    Kim, Seung Bum; Sohn, Hoon

    2008-03-01

    A new guided wave based nondestructive testing (NDT) technique is developed to detect crack damage in metallic plates commonly used in aircraft without using prior baseline data or a predetermined decision boundary. In conventional guided wave based techniques, damage is often identified by comparing the "current" data obtained from a potentially damaged condition of a structure with the "past" baseline data collected at the pristine condition of the structure. However, it has been reported that this type of pattern comparison with the baseline data can lead to increased false alarms due to its susceptibility to varying operational and environmental conditions of the structure. In order to tackle this issue, a reference-free damage detection technique is previously developed using two pairs of collocated lead zirconate titanate transducers (PZTs) placed on both sides of a plate. In this study, this reference-free technique is further advanced so that the PZT transducers can be placed only on one side of the specimen. Crack formation creates Lamb wave mode conversion due to a sudden change in the thickness of the structure. Then, the proposed technique instantly detects the appearance of the crack by extracting this mode conversion from the measured Lamb waves. This study suggests a reference-free statistical approach that enables damage classification using only the current data set. Numerical and experimental results are presented to demonstrate the applicability of the proposed technique to instantaneous crack detection.

  17. Enhanced C-band Coaxial Orthomode Transducer

    Directory of Open Access Journals (Sweden)

    S. I. Piltyay

    2014-06-01

    Full Text Available Introduction. In this paper a novel configuration of wideband coherent coaxial OMT is presented. General Design of an Orthomode Transducer. The OMT consists of elements of 3 main types: a turnstile junction between coaxial quad-ridged waveguide and 4 coaxial transmission lines; 4 right-angle coaxial junctions for each polarization; 2 antiphase power combiners/dividers. A Turnstile Junction Optimization. The optimization of a turnstile junction has been performed. Its minimized reflection coefficient is less than −28 dB in the operation frequency band 3.4–5.4 GHz. An Optimized Right-Angle Coaxial Junction. A right-angle coaxial junction has been optimized to provide reflection coefficient, which is less than −42 dB in the operation frequency band 3.4–5.4 GHz. An Antiphase Power Combiner/Divider. The optimization of an antiphase power com-biner/divider has been performed. Its minimized reflection coefficient is less than −38 dB. Conclusions. A wideband coaxial orthomode transducer has been developed for the operation frequency band 3.4–5.4 GHz. In this frequency band the reflection coefficient is less than −27 dB.

  18. Piezoelectric single crystals for ultrasonic transducers in biomedical applications

    OpenAIRE

    Zhou, Qifa; Lam, Kwok Ho; Zheng, Hairong; Qiu, Weibao; Shung, K. Kirk

    2014-01-01

    Piezoelectric single crystals, which have excellent piezoelectric properties, have extensively been employed for various sensors and actuators applications. In this paper, the state–of–art in piezoelectric single crystals for ultrasonic transducer applications is reviewed. Firstly, the basic principles and design considerations of piezoelectric ultrasonic transducers will be addressed. Then, the popular piezoelectric single crystals used for ultrasonic transducer applications, including LiNbO...

  19. Piezoelectric films for high frequency ultrasonic transducers in biomedical applications

    OpenAIRE

    Zhou, Qifa; Lau, Sienting; WU, DAWEI; Shung, K. Kirk

    2011-01-01

    Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the curr...

  20. Low-cost ultrasonic lamb-wave transducer

    Science.gov (United States)

    Kammerer, C. C.

    1978-01-01

    Transducer propagates Lamb wave through thin aluminum sheet material. Model includes two elements that measure effects of damping and loading which, in turn, are indirectly equated to bond integrity. Transducer has been used to evaluate bond integrity of aluminum facing adhesively bonded to aluminum facing. Because of versatility, it is now possible to inspect many objects of different configurations that could not be reached with earlier transducers.

  1. Broadband tonpilz underwater acoustic transducers based on multimode optimization

    OpenAIRE

    Yao, Qingshan; Jensen, Leif Bjørnø

    1997-01-01

    Head flapping has often been considered to be deleterious for obtaining a tonpilz transducer with broadband, high power performance. In the present work, broadband, high power tonpilz transducers have been designed using the finite element (FE) method. Optimized vibrational modes including the flapping mode of the head are effectively used to achieve the broadband performance. The behavior of the transducer in its longitudinal piston mode and in its flapping mode is analysed for in-air and in...

  2. An Algorithm for Selecting Transducer Element Array Positions

    Science.gov (United States)

    1988-06-01

    response. A lumped-parameter equivalent circuit of a tonpilz transducer is used to predict element amplitude and phase tolerances for different radiation...lumped-parameter equivalent circuit of a tonpilz transducer is used to predict element amplitude and phase tolerances for different radiation loadings...FIGURES p Figure Page : 2.1 A Tonpilz Type Transducer . . .............. . 6 % 2.2 The Equivalent Circuit .......... .................... 7 2.3 The

  3. Design and Test of Capacitive Micromachined Ultrasonic Transducer

    National Research Council Canada - National Science Library

    Hongliang Wang; Xiangjun Wang; Changde He; Chenyang Xue; Jijun Xiong; Wendong Zhang; Jing Miao; Yuping Li

    2014-01-01

      Currently, most capacitive micromachined ultrasound transducers, adopting surface sacrificial technology encounter various problems such as difficult cavity etch, low controllability of membrane thickness etc...

  4. MEMS acoustic emission transducers designed with high aspect ratio geometry

    Science.gov (United States)

    Saboonchi, H.; Ozevin, D.

    2013-09-01

    In this paper, micro-electro-mechanic systems (MEMS) acoustic emission (AE) transducers are manufactured using an electroplating technique. The transducers use a capacitance change as their transduction principle, and are tuned to the range 50-200 kHz. Through the electroplating technique, a thick metal layer (20 μm nickel + 0.5 μm gold) is used to form a freely moving microstructure layer. The presence of the gold layer reduces the potential corrosion of the nickel layer. A dielectric layer is deposited between the two electrodes, thus preventing the stiction phenomenon. The transducers have a measured quality factor in the range 15-30 at atmospheric pressure and are functional without vacuum packaging. The transducers are characterized using electrical and mechanical tests to identify the capacitance, resonance frequency and damping. Ultrasonic wave generation using a Q-switched laser shows the directivity of the transducer sensitivity. The comparison of the MEMS transducers with similar frequency piezoelectric transducers shows that the MEMS AE transducers have better response characteristics and sensitivity at the resonance frequency and well-defined waveform signatures (rise time and decay time) due to pure resonance behavior in the out-of-plane direction. The transducers are sensitive to a unique wave direction, which can be utilized to increase the accuracy of source localization by selecting the correct wave velocity at the structures.

  5. Radiation endurance of piezoelectric ultrasonic transducers--a review.

    Science.gov (United States)

    Sinclair, A N; Chertov, A M

    2015-03-01

    A literature survey is presented on the radiation endurance of piezoelectric ultrasonic transducer components and complete transducer assemblies, as functions of cumulative gamma dose and neutron fluence. The most extensive data on this topic has been acquired in CANDU electrical generating stations, which use piezoelectric ultrasonic transducers manufactured commercially with minor accommodation for high radiation fields. They have been found to be reliable for cumulative gamma doses of up to approximately 2 MegaGrays; a brief summary is made of the associated accommodations required to the transducer design, and the ultimate expected failure modes. Outside of the CANDU experience, endurance data have been acquired under a diverse spectrum of operating conditions; this can impede a direct comparison of the information from different sources. Much of this data is associated with transducers immersed in liquid metal coolants associated with advanced reactor designs. Significant modifications to conventional designs have led to the availability of custom transducers that can endure well over 100 MegaGrays of cumulative gamma dose. Published data on transducer endurance against neutron fluence are reviewed, but are either insufficient, or were reported with inadequate description of test conditions, to make general conclusions on transducer endurance with high confidence. Several test projects are planned or are already underway by major laboratories and research consortia to augment the store of transducer endurance data with respect to both gamma and neutron radiation.

  6. Monitoring Method for the Electrical Properties of Piezoelectric Transducer

    Institute of Scientific and Technical Information of China (English)

    李文; 朱泽琪

    2012-01-01

    The monitoring of cutting force in a vibration cutting process has a great significance in the popularization of ultrasonic vibration cutting technology. A new monitoring method of which the cutting force of ultrasonic elliptic vibration cutting is monitored using the electrical properties of transducer was proposed by studying on the relationship of cutting force, transducer electric impedance and load. A measurement system was designed for the electrical properties of transducer. The feasibility of cutting force monitoring method based on the electrical properties of piezoelectric transducer was proved by the cutting experiments.

  7. 21 CFR 892.1570 - Diagnostic ultrasonic transducer.

    Science.gov (United States)

    2010-04-01

    ... that converts electrical signals into acoustic signals and acoustic signals into electrical signals and... include transmission media for acoustically coupling the transducer to the body surface, such as...

  8. Method and results of studying conduction measuring transducers

    Energy Technology Data Exchange (ETDEWEB)

    Dunaevskii, I.G.; Korotkov, B.N.; Povkh, I.L.; Cheplyukov, V.G.

    1977-01-01

    The method and results are given for determining the sensitivity of conduction measuring transducers with a local magnetic field. The results were obtained by frequency-dependent gradation on a model pulsation velocity gauge--a thermoanemometer. The effect of measuring a transducer's diameter, inter-electrode distance and nose line forms on its spatial resolution capacity was estimated. Adjustment functions were obtained for these transducers. A concept was formulated for measuring transducers belonging to the same class. 5 references, 5 figures.

  9. A beamforming study for implementation of vibro-acoustography with a 1.75-D array transducer.

    Science.gov (United States)

    Urban, Matthew W; Chalek, Carl; Haider, Bruno; Thomenius, Kai E; Fatemi, Mostafa; Alizad, Azra

    2013-03-01

    Vibro-acoustography (VA) is an ultrasound-based imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using 1-D linear-array transducers. In this article, we discuss VA beamforming and image formation using a 1.75-D array transducer. A 1.75-D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75-D array over a 1-D linear-array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75-D array transducer offers several advantages over scanning with a linear-array transducer, including improved image resolution and contrast resulting from better elevation focusing of the imaging point-spread function.

  10. A Beamforming Study for Implementation of Vibro-acoustography with a 1.75D Array Transducer

    Science.gov (United States)

    Urban, Matthew W.; Chalek, Carl; Haider, Bruno; Thomenius, Kai E.; Fatemi, Mostafa; Alizad, Azra

    2013-01-01

    Vibro-acoustography (VA) is an ultrasound-based imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using one-dimensional (1D) linear array transducers. In this article, we discuss VA beamforming and image formation using a 1.75D array transducer. A 1.75D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75D array over a 1D linear array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75D array transducer offers several advantages over scanning with a linear array transducer including improved image resolution and contrast due to better elevation focusing of the imaging point-spread function. PMID:23475919

  11. Bio-applications of ionic polymer metal composite transducers

    Science.gov (United States)

    Aw, K. C.; McDaid, A. J.

    2014-07-01

    Traditional robotic actuators have advanced performance which in some aspects can surpass that of humans, however they are lacking when it comes to developing devices which are capable of operating together with humans. Bio-inspired transducers, for example ionic polymer metal composites (IPMC), which have similar properties to human tissue and muscle, demonstrate much future promise as candidates for replacing traditional robotic actuators in medical robotics applications. This paper outlines four biomedical robotics applications, an IPMC stepper motor, an assistive glove exoskeleton/prosthetic hand, a surgical robotic tool and a micromanipulation system. These applications have been developed using mechanical design/modelling techniques with IPMC ‘artificial muscle’ as the actuation system. The systems are designed by first simulating the performance using an IPMC model and dynamic models of the mechanical system; the appropriate advanced adaptive control schemes are then implemented to ensure that the IPMCs operate in the correct manner, robustly over time. This paper serves as an overview of the applications and concludes with some discussion on the future challenges of developing real-world IPMC applications.

  12. The Cavitation With Plate Transducer And Non Cavitation With Knob Transducer By Manihot Utilissima Fermentation The Potential Hydrogen Ph Method

    Directory of Open Access Journals (Sweden)

    Syamsul Arifin

    2015-08-01

    Full Text Available Abstract Manihot M. utilissima fermentation is popular foods and drinks for Indonesia people but it fermented foods 24 hours per day will breed fungi and anaerobic bacteriae so it will make it into acidic foods and alcoholic beverages. Ultrasonic 48 kHz 5 Vpp 1 VDC with functional generator and of the two models of transducers will have two different phenomena on M. utilissima fermentation. Methods Model-1. Radiation ultrasonic transducer plate or Flat of piezoelectric speakers2 were applied with transducers M. utilissima dipped in a test tube. Model-2. Knob or small ball ultrasonic transducer 12 balls were applied with transducers of tin knob which was connected to the copper wire2 and piezoelectricspeakers were dipped into the media M. utilissima in a test tube. After ultrasonic radiation fluid liquid from two models of transducers measured total acid in M. utilissima fermentation liquid by paper indicators of potential Hydrogen pH. The conclusion of this study can predict different phenomena namely the transducer plate of the initial pH value-acid fermentation M. utilissima can change increases the pH-value end of the base which means that the transducer plate has a cavitation phenomenon and media M. utilissima lead to the delicious food but on transducer knob that the initial pH value-acid fermentation M. utilissima will decrease more acid value so that have no phenomenon of cavitation and the media will lead M. utilissima to be alcoholic foods.

  13. Design optimization of embedded ultrasonic transducers for concrete structures assessment.

    Science.gov (United States)

    Dumoulin, Cédric; Deraemaeker, Arnaud

    2017-08-01

    In the last decades, the field of structural health monitoring and damage detection has been intensively explored. Active vibration techniques allow to excite structures at high frequency vibrations which are sensitive to small damage. Piezoelectric PZT transducers are perfect candidates for such testing due to their small size, low cost and large bandwidth. Current ultrasonic systems are based on external piezoelectric transducers which need to be placed on two faces of the concrete specimen. The limited accessibility of in-service structures makes such an arrangement often impractical. An alternative is to embed permanently low-cost transducers inside the structure. Such types of transducers have been applied successfully for the in-situ estimation of the P-wave velocity in fresh concrete, and for crack monitoring. Up to now, the design of such transducers was essentially based on trial and error, or in a few cases, on the limitation of the acoustic impedance mismatch between the PZT and concrete. In the present study, we explore the working principles of embedded piezoelectric transducers which are found to be significantly different from external transducers. One of the major challenges concerning embedded transducers is to produce very low cost transducers. We show that a practical way to achieve this imperative is to consider the radial mode of actuation of bulk PZT elements. This is done by developing a simple finite element model of a piezoelectric transducer embedded in an infinite medium. The model is coupled with a multi-objective genetic algorithm which is used to design specific ultrasonic embedded transducers both for hard and fresh concrete monitoring. The results show the efficiency of the approach and a few designs are proposed which are optimal for hard concrete, fresh concrete, or both, in a given frequency band of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Magnetoelastic Transducer Materials - a Plateable Possibility

    DEFF Research Database (Denmark)

    Jensen, Jens Dahl; Møller, Per

    2001-01-01

    A short presentation of the magnetostriction theory as well as a series of possible applications for magnetoelastic transducers are given. A review of the present state of development for these materials is discussed with relation to the various ways of manufacture. The paper is concluded...... with the presentation of a method for making magnetoelastic materials by electrochemical deposition (electroless) as tried by the authors in collaboration with the Daimler-Chrysler research centre in Ulm, Germany. First results of this work are both promising and intriguing: Sensitivities of the same order...... as the reference material Terfenol-D were obtained, but reproduction of exact magnetic properties is still critical with the new plating technique....

  15. Linear ultrasonic motor using quadrate plate transducer

    Institute of Scientific and Technical Information of China (English)

    Jiamei JIN; Chunsheng ZHAO

    2009-01-01

    A linear ultrasonic motor using a quadrate plate transducer was developed for precision positioning. This motor consists of two pairs of Pb(Zr, Ti)O3 piezo-electric ceramic elements, which are piezoelectrically excited into the second-bending mode of the motor stator's neutral surface in two orthogonal directions, on which the tops of four projections move along an elliptical trajectory, which in turn drives a contacted slider into linear motion via frictional forces. The coincident frequency of the stator is easily obtained for its coincident characteristic dimen-sion in two orthogonal directions. The performance characteristics achieved by the motor are: 1) a maximum linear speed of more than 60 mm/s; 2) a stroke of more than 150 mm; 3) a driving force of more than 5.0 N; and 4) a response time of about 2 ms.

  16. Multilayer Array Transducer for Nonlinear Ultrasound Imaging

    Science.gov (United States)

    Owen, Neil R.; Kaczkowski, Peter J.; Li, Tong; Gross, Dan; Postlewait, Steven M.; Curra, Francesco P.

    2011-09-01

    The properties of nonlinear acoustic wave propagation are known to be able to improve the resolution of ultrasound imaging, and could be used to dynamically estimate the physical properties of tissue. However, transducers capable of launching a wave that becomes nonlinear through propagation do not typically have the necessary bandwidth to detect the higher harmonics. Here we present the design and characterization of a novel multilayer transducer for high intensity transmit and broadband receive. The transmit layer was made from a narrow-band, high-power piezoceramic (PZT), with nominal frequency of 2.0 MHz, that was diced into an array of 32 elements. Each element was 0.300 mm wide and 6.3 mm in elevation, and with a pitch of 0.400 mm the overall aperture width was 12.7 mm. A quarter-wave matching layer was attached to the PZT substrate to improve transmit efficiency and bandwidth. The overlaid receive layer was made from polyvinylidene fluoride (PVDF) that had gold metalization on one side. A custom two-sided flex circuit routed electrical connections to the PZT elements and patterned the PVDF elements; the PZT and PVDF elements had identical apertures. A low viscosity and electrically nonconductive epoxy was used for all adhesion layers. Characterization of electrical parameters and acoustic output were performed per standard methods, where transmit and receive events were driven by a software-controlled ultrasound engine. Echo data, collected from ex vivo tissue and digitized at 45 MS/s, exhibited frequency content up to the 4th harmonic of the 2 MHz transmit frequency.

  17. Resonant acoustic transducer system for a well drilling string

    Science.gov (United States)

    Kent, William H.; Mitchell, Peter G.

    1981-01-01

    For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.

  18. Thermal dispersion method for an ultrasonic phased-array transducer

    Science.gov (United States)

    Choi, Euna; Lee, Wonseok; Roh, Yongrae

    2016-07-01

    When the driving voltage of an ultrasonic transducer is increased to improve the quality of ultrasound images, heat is generated inside the transducer, which can burn the patient’s skin and degrade transducer performance. In this study, the method to disperse the heat inside an ultrasonic phased-array transducer has been examined. The mechanism of temperature rise due to heat generation inside the transducer was investigated by numerical analysis and the effects of the thermal properties of the components of the transducer such as specific heat and thermal conductivity on the temperature rise were analyzed. On the basis of the results, a heat-dispersive structure was devised to reduce the temperature at the surface of the acoustic lens of the transducer. Prototype transducers were fabricated to check the efficacy of the heat-dispersive structure. By experiments, we have confirmed that the new heat-dispersive structure can reduce the internal temperature by as much as 50% in comparison with the conventional structure, which confirms the validity of the thermal dispersion mechanism developed in this work.

  19. Inter Digital Transducer Modelling through Mason Equivalent Circuit Model

    DEFF Research Database (Denmark)

    Mishra, Dipti; Singh, Abhishek; Hussain, Dil muhammed Akbar

    2016-01-01

    The frequency reliance of inter-digital transducer is analyzed with the help of MASON’s Equivalent circuit which is based on Smith’s Equivalent circuit which is further based on Foster’sNetwork. An inter-digital transducer has been demonstratedas a RLC network. The circuit is simulated by Simulat...

  20. Inter digital transducer modelling through Mason equivalent circuit model

    DEFF Research Database (Denmark)

    Mishra, Dipti; Singh, Abhishek; Hussain, Dil muhammed Akbar

    2016-01-01

    The frequency reliance of inter-digital transducer is analyzed with the help of MASON's Equivalent circuit which is based on Smith's Equivalent circuit which is further based on Foster's Network. An inter-digital transducer has been demonstrated as a RLC network. The circuit is simulated by Simul...

  1. Metal cap flexural transducers for air-coupled ultrasonics

    Science.gov (United States)

    Eriksson, T. J. R.; Dixon, S.; Ramadas, S. N.

    2015-03-01

    Ultrasonic generation and detection in fluids is inefficient due to the large difference in acoustic impedance between the piezoelectric element and the propagation medium, leading to large internal reflections and energy loss. One way of addressing the problem is to use a flexural transducer, which uses the bending modes in a thin plate or membrane. As the plate bends, it displaces the medium in front of it, hence producing sound waves. A piezoelectric flexural transducer can generate large amplitude displacements in fluid media for relatively low excitation voltages. Commercially available flexural transducers for air applications operate at 40 kHz, but there exists ultrasound applications that require significantly higher frequencies, e.g. flow measurements. Relatively little work has been done to date to understand the underlying physics of the flexural transducer, and hence how to design it to have specific properties suitable for particular applications. This paper investigates the potential of the flexural transducer and its operating principles. Two types of actuation methods are considerd: piezoelectric and electrodynamic. The piezoelectrically actuated transducer is more energy efficient and intrinsically safe, but the electrodynamic transducer has the advantage of being less sensitive to high temperature environments. The theory of vibrating plates is used to predict transducer frequency in addition to front face amplitude, which shows good correlation with experimental results.

  2. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    Science.gov (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  3. Transverse Oscillation Vector Velocity Estimation using a Phased Array Transducer

    DEFF Research Database (Denmark)

    Marcher, Jønne; Pihl, Michael Johannes; Seerup, Gert

    2012-01-01

    The Transverse Oscillation method has shown its commercial feasibility, providing the user with 2D velocity information. Todays implementation on commercial ultrasound platforms only support linear array transducers and are limited in depth. Extending the implementation to a phased array transducer...

  4. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    Science.gov (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  5. A Force Transducer from a Junk Electronic Balance

    Science.gov (United States)

    Aguilar, Horacio Munguia; Aguilar, Francisco Armenta

    2009-01-01

    It is shown how the load cell from a junk electronic balance can be used as a force transducer for physics experiments. Recovering this device is not only an inexpensive way of getting a valuable laboratory tool but also very useful didactic work on electronic instrumentation. Some experiments on mechanics with this transducer are possible after a…

  6. Ultrasonic transducer with thermomechanical excitation and piezoresistive detection

    NARCIS (Netherlands)

    Popescu, Dan S.; Dascalu, Dan C.; Elwenspoek, Michael Curt; Lammerink, Theodorus S.J.

    1996-01-01

    Ultrasonic transducer was fabricated from silicon buckled membrane using a thermo mechanical excitation and piezoresistive detection. The transducer has a 4 mm square silicon membrane, buckled with an initial deflection of 20μm, actuated by dynamically heating an aluminium ring layer, 3μm thick, wit

  7. A Force Transducer from a Junk Electronic Balance

    Science.gov (United States)

    Aguilar, Horacio Munguia; Aguilar, Francisco Armenta

    2009-01-01

    It is shown how the load cell from a junk electronic balance can be used as a force transducer for physics experiments. Recovering this device is not only an inexpensive way of getting a valuable laboratory tool but also very useful didactic work on electronic instrumentation. Some experiments on mechanics with this transducer are possible after a…

  8. Top-down tree transducers with regular look-ahead

    NARCIS (Netherlands)

    Engelfriet, Joost

    1977-01-01

    Top-down tree transducers with regular look-ahead are introduced. It is shown how these can be decomposed and composed, and how this leads to closure properties of surface sets and tree transformation languages. Particular attention is paid to deterministic tree transducers.

  9. Micro-stereolithography as a transducer design method.

    Science.gov (United States)

    Ho, K S; Bradley, R J; Billson, D R; Hutchins, D A

    2008-03-01

    This paper investigates the use of micro-stereolithography, a rapid prototyping technique, in the manufacture of transducers. It is illustrated for the production of electromagnetic acoustic transducer (EMATs) coils in both meander-line and spiral configurations. A synthetic aperture focussing technique (SAFT) has been applied to the ultrasonic signals from these devices to reconstruct images in metallic objects.

  10. Energy Conversion Efficiency of Rainbow Shape Piezoelectric Transducer

    Institute of Scientific and Technical Information of China (English)

    LIU Xiangjian; CHEN Renwen; ZHU Liya

    2012-01-01

    With the aim to enhance the energy conversion efficiency of the rainbow shape piezoelectric transducer,an analysis model of energy conversion efficiency is established based on the elastic mechanics theory and piezoelectricity theory.It can be found that the energy conversion efficiency of the rainbow shape piezoelectric transducer mainly depends on its shape parameters and material properties from the analysis model.Simulation results show that there is an optimal length ratio to generate maximum energy conversion efficiency and the optimal length ratios and energy conversion efficiencies of beryllium bronze substrate transducer and steel substrate transducer are (0.65,2.21%) and (0.65,1.64%) respectively.The optimal thickness ratios and energy conversion efficiencies of beryllium bronze substrate transducer and steel substrate transducer are (1.16,2.56%) and (1.49,1.57%) respectively.With the increase of width ratio and initial curvature radius,both the energy conversion efficiencies decrease.Moreover,beryllium bronze flexible substrate transducer is superior to the steel flexible substrate transducer.

  11. Transducer hygiene: comparison of procedures for decontamination of ultrasound transducers and their use in clinical practice.

    Science.gov (United States)

    Häggström, Mikael; Spira, Jack; Edelstam, Greta

    2015-02-01

    To determine whether current hygiene practices are appropriate during sonographic examinations. Five major hospitals in Sweden were investigated with a survey. At each hospital, the departments corresponding to the main types of sonographic examination were chosen. Personnel who were responsible for or acquainted with the local hygiene procedures completed a standardardized questionnaire. The surveys were completed by 25 departments, where the total number of sonographic examinations was approximately 20,000 per month. For transvaginal and transrectal sonographic examinations, the most common method for decontamination of the transducer was barrier protection during the procedure followed by cleansing with alcohol. Latex was the predominant cover material, but one department used polyethylene gloves, and another department used nitrile gloves. Both of these involved transvaginal ultrasonography. In transcutaneous examinations, all hospitals were using alcohol and paper or cloth for decontamination at a minimum. Transesophageal examinations were carried out without barrier protection, and decontamination was performed with an alkylating substance. The hygiene practices appear to be appropriate at most hospitals, but there is a prevalence of transducer cover materials of unacceptable permeability, as well as use of gloves on transducers despite insufficient evidence of safety. © 2015 Wiley Periodicals, Inc.

  12. Hepatitis C virus core protein inhibits interferon production by a human plasmacytoid dendritic cell line and dysregulates interferon regulatory factor-7 and signal transducer and activator of transcription (STAT 1 protein expression.

    Directory of Open Access Journals (Sweden)

    Amy E L Stone

    Full Text Available Plasmacytoid Dendritic Cells (pDCs represent a key immune cell population in the defense against viruses. pDCs detect viral pathogen associated molecular patterns (PAMPs through pattern recognition receptors (PRR. PRR/PAMP interactions trigger signaling events that induce interferon (IFN production to initiate local and systemic responses. pDCs produce Type I and Type III (IFNL IFNs in response to HCV RNA. Extracellular HCV core protein (Core is found in the circulation in chronic infection. This study defined how Core modulates PRR signaling in pDCs. Type I and III IFN expression and production following exposure to recombinant Core or β-galactosiade was assessed in human GEN2.2 cells, a pDC cell line. Core suppressed type I and III IFN production in response to TLR agonists and the HCV PAMP agonist of RIG-I. Core suppression of IFN induction was linked with decreased IRF-7 protein levels and increased non-phosphorylated STAT1 protein. Circulating Core protein interferes with PRR signaling by pDCs to suppress IFN production. Strategies to define and target Core effects on pDCs may serve to enhance IFN production and antiviral actions against HCV.

  13. Durability investigation of a group of strain gage pressure transducers

    Science.gov (United States)

    Lederer, P. S.; Hilten, J. S.

    1972-01-01

    A durability investigation was conducted on a group of eighteen bonded-wire strain gage pressure transducers with ranges of 0 to 15 psig and 0 to 100 psig using an improved version of a previously developed technique. Some of the transducers were subjected to 40 million pressure cycles at a 5-Hz rate at laboratory ambient conditions, others were cycled at a temperature of 150 F (65.6 C). The largest change in sensitivity observed was 0.22% for a 100-psig transducer subjected to 40 million pressure cycles at 150 F. The largest change in zero pressure output observed was 0.91% FS for the same transducer. None of the transducers failed completely as a result of cycling at or below full scale pressure.

  14. Transducers for Sound and Vibration - FEM Based Design

    DEFF Research Database (Denmark)

    Liu, Bin

    2001-01-01

    Design of transducers for measurement of vibration (piezoelectric accelerometers) and sound (condenser microphones) is a very labour intensive work. The design work is mostly based on experience and on simple analogies to electrical circuit design. Often a time consuming itterative loop is used......: Specification of the transducer, production of a physical prototype, measurements on the prototype, changed specification of the transducer etc. Furthermore are many transducers made based on customer requirements which also increases the amount of required design work. For these reasons there is a need...... for methods that can reduce the design time consumption and the number of itterations. The present work proposes to use finite element based programs for simulating the behaviour of a transducer with a given set of specifications. A simulation program for accelerometers was developed and has been tested...

  15. Calibration of Field II using a Convex Ultrasound Transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    Field II is an ultrasound simulation program capable of simulating the pressure scattering from inhomogeneous tissue. The simulations are based on a convolution between spatial impulse responses from the field in front of the transducer and the volt-to-surface acceleration impulse response...... of the transducer. For such simulations to reflect actual measured intensities and pressure levels, the transducer impulse response is to be known. This work presents the results of combining a modified form of a 1D linear transducer model originally suggested by Willatzen with the Field II program to calibrate...... BK-Medical (Herlev, Denmark). As input waveform for the Field model we measured the output voltage of the research amplifier, which peak voltage was limited to 31 V to avoid too high non linear effects. We measured the hydrophone output from three transducer front elements by averaging 40 shoot...

  16. Airborne Transducer Integrity under Operational Environment for Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Mohammad Saleh Salmanpour

    2016-12-01

    Full Text Available This paper investigates the robustness of permanently mounted transducers used in airborne structural health monitoring systems, when exposed to the operational environment. Typical airliners operate in a range of conditions, hence, structural health monitoring (SHM transducer robustness and integrity must be demonstrated for these environments. A set of extreme temperature, altitude and vibration environment test profiles are developed using the existing Radio Technical Commission for Aeronautics (RTCA/DO-160 test methods. Commercially available transducers and manufactured versions bonded to carbon fibre reinforced polymer (CFRP composite materials are tested. It was found that the DuraAct transducer is robust to environmental conditions tested, while the other transducer types degrade under the same conditions.

  17. Study on electrical impedance matching for broadband ultrasonic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon Woo [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Ki Bok [Korea Research Institute of Standards and Science, Center for Safety Measurement, Daejeon (Korea, Republic of); Baek, Kwang Sae [Elache Co., Busan (Korea, Republic of)

    2017-02-15

    Ultrasonic transducers with high resolution and resonant frequency are required to detect small defects (less than hundreds of μm) by ultrasonic testing. The resonance frequency and resolution of an ultrasonic transducer are closely related to the thickness of piezo-electric materials, backing materials, and the electric impedance matching technique. Among these factors, electrical impedance matching plays an important role because it can reduce the loss and reflection of ultrasonic energy differences in electrical impedance between an ultrasonic transducer and an ultrasonic defects detecting system. An LC matching circuit is the most frequently used electric matching method. It is necessary for the electrical impedance of an ultrasonic transducer to correspond to approximately 50 Ω to compensate the difference in electrical impedance between both connections. In this study, a 15 MHz immersion ultrasonic transducer was fabricated and an LC electrical impedance circuit was applied to that for having broad-band frequency characteristic.

  18. Study on the broadband tonpilz transducer with a single hole.

    Science.gov (United States)

    Xiping, He; Jing, Hu

    2009-05-01

    To get a wide-band transducer, the piezoelectric sandwiched transducer with a frustum hole in its head piece is presented in this paper. The equivalent circuit is derived, and the expressions of the equivalent mass and the equivalent impedance of the transducer are obtained by using one-dimensional (1D) design theory. Moreover, the expressions of the mechanical quality factor and the frequency bandwidth are obtained and the transmitting voltage response of the transducer is calculated by using finite element method. The theoretical results show that the frequency bandwidth of the transducer with a hole is wider than that without a hole when their resonant frequencies are almost equal. The tested results are in good agreement with the theoretical calculations.

  19. Piezoelectric single crystals for ultrasonic transducers in biomedical applications

    Science.gov (United States)

    Zhou, Qifa; Lam, Kwok Ho; Zheng, Hairong; Qiu, Weibao; Shung, K. Kirk

    2014-01-01

    Piezoelectric single crystals, which have excellent piezoelectric properties, have extensively been employed for various sensors and actuators applications. In this paper, the state–of–art in piezoelectric single crystals for ultrasonic transducer applications is reviewed. Firstly, the basic principles and design considerations of piezoelectric ultrasonic transducers will be addressed. Then, the popular piezoelectric single crystals used for ultrasonic transducer applications, including LiNbO3 (LN), PMN–PT and PIN–PMN–PT, will be introduced. After describing the preparation and performance of the single crystals, the recent development of both the single–element and array transducers fabricated using the single crystals will be presented. Finally, various biomedical applications including eye imaging, intravascular imaging, blood flow measurement, photoacoustic imaging, and microbeam applications of the single crystal transducers will be discussed. PMID:25386032

  20. Ultrasound transducer positioning aid for fetal heart rate monitoring.

    Science.gov (United States)

    Hamelmann, Paul; Kolen, Alex; Schmitt, Lars; Vullings, Rik; van Assen, Hans; Mischi, Massimo; Demi, Libertario; van Laar, Judith; Bergmans, Jan

    2016-08-01

    Fetal heart rate (fHR) monitoring is usually performed by Doppler ultrasound (US) techniques. For reliable fHR measurements it is required that the fetal heart is located within the US beam. In clinical practice, clinicians palpate the maternal abdomen to identify the fetal presentation and then the US transducer is fixated on the maternal abdomen where the best fHR signal can be obtained. Finding the optimal transducer position is done by listening to the strength of the Doppler audio output and relying on a signal quality indicator of the cardiotocographic (CTG) measurement system. Due to displacement of the US transducer or displacement of the fetal heart out of the US beam, the fHR signal may be lost. Therefore, it is often necessary that the obstetrician repeats the tedious procedure of US transducer positioning to avoid long periods of fHR signal loss. An intuitive US transducer positioning aid would be highly desirable to increase the work flow for the clinical staff. In this paper, the possibility to determine the fetal heart location with respect to the transducer by exploiting the received signal power in the transducer elements is shown. A commercially available US transducer used for fHR monitoring is connected to an US open platform, which allows individual driving of the elements and raw US data acquisition. Based on the power of the received Doppler signals in the transducer elements, the fetal heart location can be estimated. A beating fetal heart setup was designed and realized for validation. The experimental results show the feasibility of estimating the fetal heart location with the proposed method. This can be used to support clinicians in finding the optimal transducer position for fHR monitoring more easily.

  1. Controlling the position and the dislocation of the middle ear transducer with high-resolution computed tomography and digital volume tomography: implications for the transducers' design.

    Science.gov (United States)

    Kontorinis, Georgios; Giesemann, Anja M; Witt, Thomas; Goetz, Friedrich; Schwab, Burkard

    2012-04-01

    A minimal tip dislocation of the middle ear transducer (MET(®), Otologics Ltd) may result in poor hearing performance. Our objective was to examine if a defined MET dislocation can be diagnosed by high-resolution computed tomography (HRCT) or digital volume tomography (DVT). A human cadaver head was sequentially implanted with different MET tips (incus application) including a ceramic tip (T 1c), a titanium tip (T 1t), a new, thinner titanium tip (T 2), and a spherical titanium tip (Ts). HRCT and DVT studies were performed. Afterward, the tips were pulled back 0.5 mm, so that they were not attached to the incus. HRCT and DVT scans were repeated to identify the dislocation. Using the best plain in HRCT images, the dislocation of the transducer could be measured reliably and reproducibly in half of the cases. In particular, the precise positioning and the dislocation could be identified when T 1t and Ts were implanted, with the Ts showing the best visibility. DVT failed in recognizing the dislocation in all cases. The identification of MET tip's dislocation with HRCT depends on the shape, size, and material of the tip. This knowledge is useful for the design of the implants, as determination of the right position of the middle ear transducer may be proven important for the hearing outcome. In some cases, however, surgical exploration may still be required. Although DVT represents a promising imaging method for the otologists, it can barely help when MET dislocation is suspected.

  2. Dynamics of electromagnetically-transduced microresonators

    Science.gov (United States)

    Sabater, Andrew B.

    Electromagnetic transduction is a means of actuating and sensing microelectromechanical systems (MEMS) through the interaction of electric and magnetic fields. Electromagnetically-transduced devices are Lorentz force actuated and sensed via an induced electromotive force (EMF). As such, transduction requires that the vibrations of one of these devices take place within a magnetic field. Provided one can leverage relatively recent advances with rare-earth magnets or complementary metal-oxide-semiconductor (CMOS) fabrication for magnetic field generation, electromagnetic transduction offers many distinct advantages over other methods of actuating and sensing MEMS. These advantages include the ability to generate large forces and moments that are linearly related to the supplied current, comparatively low power consumption metrics obtained with comparatively-low excitation voltages, and comparatively-simple device geometries that do not interfere with transduction. This type of transduction also facilitates operation in fluidic or harsh environments. In addition, an electromagnetically-transduced microresonator (ETM) could be used in the future for numerous applications which utilize a microresonator, such as electrical signal processing and resonant-based mass sensing, as well as self-sustaining oscillators. Other potential applications that are relatively unique to ETMs are a product of electromagnetic transduction, like magnetic field sensing. Arrays of electromagnetically-transduced devices could also be used to improve a sensor's throughput, or the total amount of sensed information, as it is comparatively-easy to electrically-couple multiple devices together. The efforts associated with the design, fabrication and characterization in both low-pressure and atmospheric conditions of one such array that has multiple, easily-tailored resonances with single-input, single-output (SISO) characteristics are documented in this dissertation. This type of electromagnetic

  3. Dual-frequency transducer for nonlinear contrast agent imaging.

    Science.gov (United States)

    Guiroy, Axel; Novell, Anthony; Ringgaard, Erling; Lou-Moeller, Rasmus; Grégoire, Jean-Marc; Abellard, André-Pierre; Zawada, Tomasz; Bouakaz, Ayache; Levassort, Franck

    2013-12-01

    Detection of high-order nonlinear components issued from microbubbles has emerged as a sensitive method for contrast agent imaging. Nevertheless, the detection of these high-frequency components, including the third, fourth, and fifth harmonics, remains challenging because of the lack of transducer sensitivity and bandwidth. In this context, we propose a new design of imaging transducer based on a simple fabrication process for high-frequency nonlinear imaging. The transducer is composed of two elements: the outer low-frequency (LF) element was centered at 4 MHz and used in transmit mode, whereas the inner high-frequency (HF) element centered at 14 MHz was used in receive mode. The center element was pad-printed using a lead zirconate titanate (PZT) paste. The outer element was molded using a commercial PZT, and curved porous unpoled PZT was used as backing. Each piezoelectric element was characterized to determine the electromechanical performance with thickness coupling factor around 45%. After the assembly of the two transducer elements, hydrophone measurements (electroacoustic responses and radiation patterns) were carried out and demonstrated a large bandwidth (70% at -3 dB) of the HF transducer. Finally, the transducer was evaluated for contrast agent imaging using contrast agent microbubbles. The results showed that harmonic components (up to the sixth harmonic) of the microbubbles were successfully detected. Moreover, images from a flow phantom were acquired and demonstrated the potential of the transducer for high-frequency nonlinear contrast imaging.

  4. Design of advanced ultrasonic transducers for welding devices.

    Science.gov (United States)

    Parrini, L

    2001-11-01

    A new high frequency ultrasonic transducer has been conceived, designed, prototyped, and tested. In the design phase, an advanced approach was used and established. The method is based on an initial design estimate obtained with finite element method (FEM) simulations. The simulated ultrasonic transducers and resonators are then built and characterized experimentally through laser interferometry and electrical resonance spectra. The comparison of simulation results with experimental data allows the parameters of FEM models to be adjusted and optimized. The achieved FEM simulations exhibit a remarkably high predictive potential and allow full control of the vibration behavior of the transducer. The new transducer is mounted on a wire bonder with a flange whose special geometry was calculated by means of FEM simulations. This flange allows the transducer to be attached on the wire bonder, not only in longitudinal nodes, but also in radial nodes of the ultrasonic field excited in the horn. This leads to a total decoupling of the transducer to the wire bonder, which has not been achieved so far. The new approach to mount ultrasonic transducers on a welding device is of major importance, not only for wire bonding, but also for all high power ultrasound applications and has been patented.

  5. TRANSDUCER GENERATED ARRAYS OF ROBOTIC NANO-ARMS.

    Science.gov (United States)

    Dolzhenko, Egor; Jonoska, Nataša; Seeman, Nadrian C

    2010-06-01

    We consider sets of two-dimensional arrays, called here transducer generated languages, obtained by iterative applications of transducers (finite state automata with output). Each transducer generates a set of blocks of symbols such that the bottom row of a block is an input string accepted by the transducer and, by iterative application of the transducer, each row of the block is an output of the transducer on the preceding row. We show how these arrays can be implemented through molecular assembly of triple crossover DNA molecules. Such assembly could serve as a scaffold for arranging molecular robotic arms capable for simultaneous movements. We observe that transducer generated languages define a class of languages which is a proper subclass of recognizable picture languages, but it containing the class of all factorial local two-dimensional languages. By taking the average growth rate of the number of blocks in the language as a measure of its complexity, we further observe that arrays with high complexity patterns can be generated in this way.

  6. Design, analysis, and modeling of giant magnetostrictive transducers

    Science.gov (United States)

    Calkins, Frederick Theodore

    The increased use of giant magnetostrictive, Terfenol-D transducers in a wide variety of applications has led to a need for greater understanding of the materials performance. This dissertation attempts to add to the Terfenol-D transducer body of knowledge by providing an in-depth analysis and modeling of an experimental transducer. A description of the magnetostriction process related to Terfenol-D includes a discussion of material properties, production methods, and the effect of mechanical stress, magnetization, and temperature on the material performance. The understanding of the Terfenol-D material performance provides the basis for an analysis of the performance of a Terfenol-D transducer. Issues related to the design and utilization of the Terfenol-D material in the transducers are considered, including the magnetic circuit, application of mechanical prestress, and tuning of the mechanical resonance. Experimental results from two broadband, Tonpilz design transducers show the effects of operating conditions (prestress, magnetic bias, AC magnetization amplitude, and frequency) on performance. In an effort to understand and utlilize the rich performance space described by the experimental results a variety of models are considered. An overview of models applicable to Terfenol-D and Terfenol-D transducers is provided, including a discussion of modeling criteria. The Jiles-Atherton model of ferromagnetic hysteresis is employed to describe the quasi-static transducer performance. This model requires the estimation of only six physically-based parameters to accurately simulate performance. The model is shown to be robust with respect to model parameters over a range of mechanical prestress, magnetic biases, and AC magnetic field amplitudes, allowing predictive capability within these ranges. An additional model, based on electroacoustics theory, explains trends in the frequency domain and facilitates an analysis of efficiency based on impedance and admittance

  7. Bonding and impedance matching of acoustic transducers using silver epoxy.

    Science.gov (United States)

    Son, Kyu Tak; Lee, Chin C

    2012-04-01

    Silver epoxy was selected to bond transducer plates on glass substrates. The properties and thickness of the bonding medium affect the electrical input impedance of the transducer. Thus, the thickness of the silver epoxy bonding layer was used as a design parameter to optimize the structure for the transducer input impedance to match the 50 Ω output impedance of most radio frequency (RF) generators. Simulation and experimental results show that nearly perfect matching is achieved without using any matching circuit. At the matching condition, the transducer operates at a frequency band a little bit below the half-wavelength resonant frequency of the piezoelectric plate. In experiments, lead titanate (PT) piezoelectric plates were employed. Both full-size, 11.5 mm × 2 mm × 0.4 mm, and half-size, 5.75 mm × 2 mm × 0.4 mm, can be well matched using optimal silver epoxy thickness. The transducer assemblies demonstrate high efficiency. The conversion loss from electrical power to acoustic power in soda-lime glass is 4.3 dB. This loss is low considering the fact that the transducers operate at off-resonance by 12%. With proper choice of silver epoxy thickness, the transducer can be matched at the fundamental, the 3rd and 5th harmonic frequencies. This leads to the possible realization of triple-band transducers. Reliability was assessed with thermal cycling test according to Telcordia GR-468-Core recommendation. Of the 30 transducer assemblies tested, none broke until 2900 cycles and 27 have sustained beyond 4050 cycles.

  8. Cytotoxic-T-Lymphocyte-Mediated Elimination of Target Cells Transduced with Engineered Adeno-Associated Virus Type 2 Vector In Vivo▿

    OpenAIRE

    Li, Chengwen; Hirsch, Matt; DiPrimio, Nina; Asokan, Aravind; Goudy, Kevin; Tisch, Roland; Samulski, R. Jude

    2009-01-01

    A recent clinical trial in patients with hemophilia B has suggested that adeno-associated virus (AAV) capsid-specific cytotoxic T lymphocytes (CTLs) eliminated AAV-transduced hepatocytes and resulted in therapeutic failure. AAV capsids elicit a CTL response in animal models; however, these capsid-specific CTLs fail to kill AAV-transduced target cells in mice. To better model the human clinical trial data in mice, we introduced an immunodominant epitope derived from ovalbumin (OVA; SIINFEKL) i...

  9. Barriers in contribution of human mesenchymal stem cells to murine muscle regeneration.

    Science.gov (United States)

    de la Garza-Rodea, Anabel S; Boersma, Hester; Dambrot, Cheryl; de Vries, Antoine Af; van Bekkum, Dirk W; Knaän-Shanzer, Shoshan

    2015-05-20

    To study regeneration of damaged human and murine muscle implants and the contribution of added xenogeneic mesenchymal stem cells (MSCs). Minced human or mouse skeletal muscle tissues were implanted together with human or mouse MSCs subcutaneously on the back of non-obese diabetic/severe combined immunodeficient mice. The muscle tissues (both human and murine) were minced with scalpels into small pieces (< 1 mm(3)) and aliquoted in portions of 200 mm(3). These portions were either cryopreserved in 10% dimethylsulfoxide or freshly implanted. Syngeneic or xenogeneic MSCs were added to the minced muscles directly before implantation. Implants were collected at 7, 14, 30 or 45 d after transplantation and processed for (immuno)histological analysis. The progression of muscle regeneration was assessed using a standard histological staining (hematoxylin-phloxin-saffron). Antibodies recognizing Pax7 and von Willebrand factor were used to detect the presence of satellite cells and blood vessels, respectively. To enable detection of the bone marrow-derived MSCs or their derivatives we used MSCs previously transduced with lentiviral vectors expressing a cytoplasmic LacZ gene. X-gal staining of the fixed tissues was used to detect β-galactosidase-positive cells and myofibers. Myoregeneration in implants of fresh murine muscle was evident as early as day 7, and progressed with time to occupy 50% to 70% of the implants. Regeneration of fresh human muscle was slower. These observations of fresh muscle implants were in contrast to the regeneration of cryopreserved murine muscle that proceeded similarly to that of fresh tissue except for day 45 (P < 0.05). Cryopreserved human muscle showed minimal regeneration, suggesting that the freezing procedure was detrimental to human satellite cells. In fresh and cryopreserved mouse muscle supplemented with LacZ-tagged mouse MSCs, β-galactosidase-positive myofibers were identified early after grafting at the well-vascularized periphery of

  10. An improved vector system for constructing transcriptional lacZ fusions: analysis of regulation of the dnaA, dnaN, recF and gyrB genes of Escherichia coli.

    Science.gov (United States)

    Macián, F; Pérez-Roger, I; Armengod, M E

    1994-07-22

    We describe a new vector system for the in vitro construction of transcriptional fusions to the lacZ gene, which is expressed from the translational start signals of galK. The galK ribosome-binding site (RBS) and its natural preceding region ensure a constant efficiency for lacZ translation and, thus, the beta-galactosidase (beta Gal) production of a given fusion is directly proportional to the in vivo transcriptional activity of the inserted DNA fragment. Single-copy lambda prophage versions of multicopy constructs can be made by in vivo recombination. We use this system to compare the transcriptional activities of the promoters present in the dnaA-dnaN-recF-gyrB cluster. The order of strength of these promoters is gyrB > dnaA > recF > dnaN. It is assumed that gyrB belongs to the dnaA-dnaN-recF operon, because the short recF-gyrB intercistronic region does not contain a terminator. By using this new vector system, we have detected strong termination signals within recF that are functional even when recF is translated at its normal rate. The low level of transcription coming to the end of recF, and the highest activity of the gyrB promoter, as well as results obtained with several gyrB::lacZ translational fusions, support the conclusion that gyrB is predominantly expressed from its own promoter under standard growth conditions. Finally, we have found that transcription from the dnaA promoters is constant at different growth rates. This supports the idea that autoregulation of the dnaA gene is responsible for the coupling of the DnaA protein synthesis to cell mass increase, and accumulation of DnaA protein governs the initiation of chromosome replication.

  11. USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

    Science.gov (United States)

    Weaver, H.L.; Campbell, G.S.

    1985-01-01

    Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

  12. Dynamic mechanism and its modelling of micromachined electrostatic ultrasonic transducers

    Institute of Scientific and Technical Information of China (English)

    葛立峰

    1999-01-01

    A tensile-plate-on-air-spring model (or called TDK model for short) for micromachined electrostatic ultrasonic transducers has been developed based on a thorough investigation of their dynamic mechanism. The mechanical stiffness effects caused by the compressibility of air gaps, bending stiffness of the diaphragm and in-plane tension applied to the diaphragm, together with an electrostatic negative stiffness effect are included completely in the model. Desired particular fundamental frequency and bandwidth can be obtained by only properly tailoring the geometry, dimensions and materials of transducers according to the model, which provides thereby a reliable theoretical basis for the understanding and optimised design of such transducers.

  13. A thermal insulation method for a piezoelectric transducer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed.

  14. Optimization of ultrasonic transducers for selective guided wave actuation

    Science.gov (United States)

    Miszczynski, Mateusz; Packo, Pawel; Zbyrad, Paulina; Stepinski, Tadeusz; Uhl, Tadeusz; Lis, Jerzy; Wiatr, Kazimierz

    2016-04-01

    The application of guided waves using surface-bonded piezoceramic transducers for nondestructive testing (NDT) and Structural Health Monitoring (SHM) have shown great potential. However, due to difficulty in identification of individual wave modes resulting from their dispersive and multi-modal nature, selective mode excitement methods are highly desired. The presented work focuses on an optimization-based approach to design of a piezoelectric transducer for selective guided waves generation. The concept of the presented framework involves a Finite Element Method (FEM) model in the optimization process. The material of the transducer is optimized in topological sense with the aim of tuning piezoelectric properties for actuation of specific guided wave modes.

  15. Broadband tonpilz underwater acoustic transducers based on multimode optimization

    DEFF Research Database (Denmark)

    Yao, Qingshan; Jensen, Leif Bjørnø

    1997-01-01

    Head flapping has often been considered to be deleterious for obtaining a tonpilz transducer with broadband, high power performance. In the present work, broadband, high power tonpilz transducers have been designed using the finite element (FE) method. Optimized vibrational modes including...... the flapping mode of the head are effectively used to achieve the broadband performance. The behavior of the transducer in its longitudinal piston mode and in its flapping mode is analysed for in-air and in-water situations. For the 37.8% bandwidth of the center frequency from 28.5 to 41.8 kHz, the amplitude...

  16. Design and fabrication of a low frequency giant magnetostrictive transducer

    Energy Technology Data Exchange (ETDEWEB)

    Dhilsha, K.R. [Nat. Inst. of Ocean Technol, Madras (India); Markandeyulu, G.; Subrahmanyeswara Rao, B.V.P.; Rama Rao, K.V.S. [Magnetism and Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology, Madras 600 036 (India)

    1997-08-01

    A Tonpilz-type single ended transducer employing two rods of giant magnetostrictive materials has been fabricated and its underwater acoustic characteristics have been studied. The transducer resonated at a frequency of 3.1 kHz in air and at 2.65 kHz in water with a Q factor of 6. The TCR and RS at resonance in water have been measured to be 172.1 dB re 1 {mu}Pa/A at 1 m and -196.7 dB re 1 V/{mu}Pa respectively. The dimensions of the transducer are 60 mm in diameter and 110 mm long. (orig.)

  17. Ultrasonic Transducer Peak-to-Peak Optical Measurement

    Directory of Open Access Journals (Sweden)

    Pavel Skarvada

    2012-01-01

    Full Text Available Possible optical setups for measurement of the peak-to-peak value of an ultrasonic transducer are described in this work. The Michelson interferometer with the calibrated nanopositioner in reference path and laser Doppler vibrometer were used for the basic measurement of vibration displacement. Langevin type of ultrasonic transducer is used for the purposes of Electro-Ultrasonic Nonlinear Spectroscopy (EUNS. Parameters of produced mechanical vibration have to been well known for EUNS. Moreover, a monitoring of mechanical vibration frequency shift with a mass load and sample-transducer coupling is important for EUNS measurement.

  18. Broadband electrical impedance matching for piezoelectric ultrasound transducers.

    Science.gov (United States)

    Huang, Haiying; Paramo, Daniel

    2011-12-01

    This paper presents a systematic method for designing broadband electrical impedance matching networks for piezoelectric ultrasound transducers. The design process involves three steps: 1) determine the equivalent circuit of the unmatched piezoelectric transducer based on its measured admittance; 2) design a set of impedance matching networks using a computerized Smith chart; and 3) establish the simulation model of the matched transducer to evaluate the gain and bandwidth of the impedance matching networks. The effectiveness of the presented approach is demonstrated through the design, implementation, and characterization of impedance matching networks for a broadband acoustic emission sensor. The impedance matching network improved the power of the acquired signal by 9 times.

  19. Signal transducer and activator of transcription 3 regulation by novel binding partners

    Institute of Scientific and Technical Information of China (English)

    Tadashi; Matsuda; Ryuta; Muromoto; Yuichi; Sekine; Sumihito; Togi; Yuichi; Kitai; Shigeyuki; Kon; Kenji; Oritani

    2015-01-01

    Signal transducers and activators of transcription(STATs) mediate essential signals for various biological processes,including immune responses,hematopoiesis,and neurogenesis. STAT3,for example,is involved in the pathogenesis of various human diseases,including cancers,autoimmune and inflammatory disorders. STAT3 activation is therefore tightly regulated at multiple levels to prevent these pathological conditions. A number of proteins have been reported to associate with STAT3 and regulate its activity. These STAT3-interacting proteins function to modulate STAT3-mediated signaling at various steps and mediate the crosstalk of STAT3 with other cellular signaling pathways. This article reviews the roles of novel STAT3 binding partners such as DAXX,zipperinteracting protein kinase,Krüppel-associated box-associated protein 1,Y14,PDZ and LIM domain 2 and signal transducing adaptor protein-2,in the regulation of STAT3-mediated signaling.

  20. Non-contact optoacoustic imaging with focused air-coupled transducers

    Energy Technology Data Exchange (ETDEWEB)

    Deán-Ben, X. Luís [Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg (Germany); Pang, Genny A.; Razansky, Daniel, E-mail: dr@tum.de [Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg (Germany); School of Medicine, Technische Universität München (TUM), Munich (Germany); Montero de Espinosa, Francisco [CSIC, Institute of Physics and Communication Technologies, Madrid (Spain)

    2015-08-03

    Non-contact optoacoustic imaging employing raster-scanning of a spherically focused air-coupled ultrasound transducer is showcased herein. Optoacoustic excitation with laser fluence within the maximal permissible human exposure limits in the visible and near-infrared spectra is applied to objects with characteristic dimensions smaller than 1 mm and absorption properties representative of the whole blood at near-infrared wavelengths, and these signals are shown to be detectable without contact to the sample using an air-coupled transducer with reasonable signal averaging. Optoacoustic images of vessel-mimicking tubes embedded in an agar phantom captured with this non-contact sensing technique are also showcased. These initial results indicate that an air-coupled ultrasound detection approach can be suitable for non-contact biomedical imaging with optoacoustics.

  1. Estimation of contact force and amount of hair between skin and bone-conducted sound transducer using electrical impedance

    Science.gov (United States)

    Ogiso, Satoki; Mizutani, Koichi; Zempo, Keiichi; Wakatsuki, Naoto; Maeda, Yuka

    2017-07-01

    Noninvasive bone-conducted hearing aids require the consistent fitting of transducers for consistent hearing. In this paper, a method of estimating the contact force and amount of hair between a person’s skin and a bone-conducted sound transducer using electrical impedance is proposed. Experiments are conducted with a human surface model consisting of hair, skin, and bone. The estimator is implemented with a three-layered neural network. Ten measurements for 70 conditions are conducted by changing the contact force from 0 to 5 N and the amount of hair from 0 to 169.6 mm3. With the trained estimator, it is possible to estimate contact force and the intermediate material thickness with mean errors of 0.025 N and 0.424 mm3. This result supports the feasibility of the proposed method and contributes to the reproducible placement of the bone-conducted sound transducer.

  2. Lunar Advanced Volatile Analysis Subsystem: Pressure Transducer Trade Study

    Science.gov (United States)

    Kang, Edward Shinuk

    2017-01-01

    In Situ Resource Utilization (ISRU) is a key factor in paving the way for the future of human space exploration. The ability to harvest resources on foreign astronomical objects to produce consumables and propellant offers potential reduction in mission cost and risk. Through previous missions, the existence of water ice at the poles of the moon has been identified, however the feasibility of water extraction for resources remains unanswered. The Resource Prospector (RP) mission is currently in development to provide ground truth, and will enable us to characterize the distribution of water at one of the lunar poles. Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) is the primary payload on RP that will be used in conjunction with a rover. RESOLVE contains multiple instruments for systematically identifying the presence of water. The main process involves the use of two systems within RESOLVE: the Oxygen Volatile Extraction Node (OVEN) and Lunar Advanced Volatile Analysis (LAVA). Within the LAVA subsystem, there are multiple calculations that depend on accurate pressure readings. One of the most important instances where pressure transducers (PT) are used is for calculating the number of moles in a gas transfer from the OVEN subsystem. As a critical component of the main process, a mixture of custom and commercial off the shelf (COTS) PTs are currently being tested in the expected operating environment to eventually down select an option for integrated testing in the LAVA engineering test unit (ETU).

  3. Electromechanically active polymer transducers: research in Europe

    Science.gov (United States)

    Carpi, Federico; Graz, Ingrid; Jager, Edwin; Ladegaard Skov, Anne; Vidal, Frédéric

    2013-10-01

    Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical flexibility, low density, structural simplicity, ease of processing and scalability, no acoustic noise and, in most cases, low costs. Since many of these characteristics can also describe natural muscle tissues from an engineering standpoint, it is not surprising that EAP transducers are sometimes also referred to as 'muscle-like smart materials' or 'artificial muscles'. They are used not only to generate motion, but also to sense or harvest energy from it. In particular, EAP electromechanical transducers are studied for applications that can benefit from their 'biomimetic' characteristics, with possible usages from the micro- to the macro-scale, spanning several disciplines, such as mechatronics, robotics, automation, biotechnology and biomedical engineering, haptics, fluidics, optics and acoustics. Currently, the EAP field is just undergoing its initial transition from academic research into commercialization, with companies starting to invest in this technology and the first products appearing on the market. This focus issue is intentionally aimed at gathering contributions from the most influential European groups working in the EAP field. In fact, today Europe hosts the broadest EAP community worldwide. The rapid expansion of the EAP field in Europe, where it historically has strong roots, has stimulated the creation of the 'European Scientific Network for Artificial

  4. Wideband Single Crystal Transducer for Bone Characterization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS proposes to develop a simple-to-use, launch capable, ultrasound transducer that is capable of producing the necessary bandwidth to accurately determine in vivo...

  5. Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

    KAUST Repository

    Viržonis, Darius

    2013-10-22

    The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here by presentin

  6. Performance Evaluation of Pressure Transducers for Water Impacts

    Science.gov (United States)

    Vassilakos, Gregory J.; Stegall, David E.; Treadway, Sean

    2012-01-01

    The Orion Multi-Purpose Crew Vehicle is being designed for water landings. In order to benchmark the ability of engineering tools to predict water landing loads, test programs are underway for scale model and full-scale water impacts. These test programs are predicated on the reliable measurement of impact pressure histories. Tests have been performed with a variety of pressure transducers from various manufacturers. Both piezoelectric and piezoresistive devices have been tested. Effects such as thermal shock, pinching of the transducer head, and flushness of the transducer mounting have been studied. Data acquisition issues such as sampling rate and anti-aliasing filtering also have been studied. The response of pressure transducers have been compared side-by-side on an impulse test rig and on a 20-inch diameter hemisphere dropped into a pool of water. The results have identified a range of viable configurations for pressure measurement dependent on the objectives of the test program.

  7. Transducer for Tension Force Measuring of Strip Materials

    Directory of Open Access Journals (Sweden)

    Emad S. Addasi

    2005-01-01

    Full Text Available In winding-up motor drive systems, such as that used in textile industry, it is very important to get a constant tension force for the winding strip material (thread and to reduce its oscillations. This study recommends a transducer with a special design to be used in the mentioned motor drive systems. By using a piston damper, spring, levers, slider and other simple components the suggested sensor (transducer can be used to control the motor speed for getting the required thread tension force. Also the suggested transducer avoids the disadvantage of other used conventional transducer: the parasitic (detrimental oscillations of the thread tension force, which affect the quality of the produced strip material.

  8. Spatial impulse response of a rectangular double curved transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2012-01-01

    Calculation of the pressure field from transducers having both a convex and a concave surface geometry is a complicated assignment that often is accomplished by subdividing the transducer surface into smaller flat elements of which the spatial impulse response is known. This method is often seen...... applied to curved transducers because an analytical solution is un-known. In this work a semi-analytical algorithm for the exact solution to a first order in diffraction effect of the spatial impulse response of rectangular shaped double curved transducers is presented. The algorithm and an approximation...... approximations ranging from 0.03 % to 0.8 % relative to a numerical solution for the spatial impulse response. It is shown that the presented algorithm gives consistent results with Field II for a linear flat, a linear focused, and a convex non-focused element. Best solution was found to be 0.01 % with a three...

  9. Studies on coaxial circular array for underwater transducer applications

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.

    This thesis presents analytical methods to study important aspects of a coaxial circular array for wideband underwater transducer application. It begins with detailed theoretical study of a coaxial circular array of three turns and an analysis...

  10. Lithium niobate ultrasonic transducer design for Enhanced Oil Recovery.

    Science.gov (United States)

    Wang, Zhenjun; Xu, Yuanming; Gu, Yuting

    2015-11-01

    Due to the strong piezoelectric effect possessed by lithium niobate, a new idea that uses lithium niobate to design high-power ultrasonic transducer for Enhanced Oil Recovery technology is proposed. The purpose of this paper is to lay the foundation for the further research and development of high-power ultrasonic oil production technique. The main contents of this paper are as follows: firstly, structure design technique and application of a new high-power ultrasonic transducer are introduced; secondly, the experiment for reducing the viscosity of super heavy oil by this transducer is done, the optimum ultrasonic parameters for reducing the viscosity of super heavy oil are given. Experimental results show that heavy large molecules in super heavy oil can be cracked into light hydrocarbon substances under strong cavitation effect caused by high-intensity ultrasonic wave. Experiment proves that it is indeed feasible to design high-power ultrasonic transducer for ultrasonic oil production technology using lithium niobate.

  11. Finite element analysis for acoustic characteristics of a magnetostrictive transducer

    Science.gov (United States)

    Kim, Jaehwan; Jung, Eunmi

    2005-12-01

    This paper presents a finite element analysis for a magnetostrictive transducer by taking into account the nonlinear behavior of the magnetostrictive material and fluid interaction. A finite element formulation is derived for the coupling of magnetostrictive and elastic materials based upon a separated magnetic and displacement field calculation and a curve fitting technique of material properties. The fluid and structure coupled problem is taken into account based upon pressure and velocity potential fields formulation. Infinite wave envelope elements are introduced at an artificial boundary to deal with the infinite fluid domain. A finite element code for the analysis of a magnetostrictive transducer is developed. A magnetostrictive tonpilz transducer is taken as an example and verification for the developed program is made by comparing with a commercial code. The acoustic characteristics of the magnetostrictive tonpilz transducer are calculated in terms of radiation pattern and transmitted current response.

  12. Traceable dynamic calibration of force transducers by primary means

    Science.gov (United States)

    Vlajic, Nicholas; Chijioke, Ako

    2016-08-01

    We describe an apparatus for traceable, dynamic calibration of force transducers using harmonic excitation, and report calibration measurements of force transducers using this apparatus. In this system, the force applied to the transducer is produced by the acceleration of an attached mass, and is determined according to Newton’s second law, F  =  ma. The acceleration is measured by primary means, using laser interferometry. The capabilities of this system are demonstrated by performing dynamic calibrations of two shear-web-type force transducers up to a frequency of 2 kHz, with an expanded uncertainty below 1.2%. We give an account of all significant sources of uncertainty, including a detailed consideration of the effects of dynamic tilting (rocking), which is a leading source of uncertainty in such harmonic force calibration systems.

  13. Class D audio amplifiers for high voltage capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis

    voltage capacitive transducers can be constructed with THD+N below 0.1 % and peak efficiency above 80 %. However the complexity of the amplifier combined with the current high cost of components, makes the technology of DEAP based loudspeaker unfeasible. Suggestions to future work in the pursuit...... of high volume, weight, and cost. High efficient class D amplifiers are now widely available offering power densities, that their linear counterparts can not match. Unlike the technology of audio amplifiers, the loudspeaker is still based on the traditional electrodynamic transducer invented by C.W. Rice....... Due to the similarities between the electrostatic loudspeaker and the DEAP transducer, the state-of-the-art has a special focus on amplifiers for electrostatic loudspeakers. Amplifiers for other type of capacitive transducers like piezoelectric ones are also considered. Finally the current state...

  14. Tunable interdigital transducers made of piezoelectric macro-fiber composite

    Science.gov (United States)

    Mańka, Michał; Martowicz, Adam; Rosiek, Mateusz; Stepinski, Tadeusz; Uhl, Tadeusz

    2016-11-01

    The number of applications of Lamb waves (LWs) based structural health monitoring (SHM) has significantly increased in recent decades. The growth of interest results from several advantages of this diagnostic technique, that is, considerable mode selectivity and directivity that allow for the assessment of the technical condition of a monitored structure. Successful applications of LWs in the field of SHM stimulate continuous improvement of the transducers’ design to enable capturing more reliable diagnostic data. The paper introduces a new type of transducer that may be used in the LWs based SHM systems, namely tunable-interdigital transducer (T-IDT) based on macro-fiber composites (MFC). The authors provide a short overview on different types of transducers that may be used in SHM applications, followed by a detailed description of the structure of proposed T-IDT. Finally, the results of numerical and experimental tests carried out employing the proposed transducer are discussed and compared to those obtained with a traditional IDT.

  15. Phylocomposer and phylodirector: analysis and visualization of transducer indel models.

    Science.gov (United States)

    Holmes, Ian

    2007-12-01

    Finite-state string transducers are probabilistic tools similar to Hidden Markov Models that can be systematically extended to large number of sequences related by indel and substitution processes on phylogenetic trees. The number of states in such models grows exponentially with the number of nodes in the tree, with the consequence that even quite small trees can be difficult to analyze or visualize. Here, we present two tools, phylocomposer and phylodirector, for working with string transducers. The former tool implements previously described composition algorithms for extending transducers to arbitrary tree topologies, while the latter generates short animations for arbitrary input alignments and phylogenetic trees, illustrating the state path through the composed transducer. Phylocomposer and phylodirector are freely available at http://biowiki.org/PhyloComposer and http://biowiki.org/PhyloDirector

  16. A Novel Drive Option for Piezoelectric Ultrasonic Transducers

    OpenAIRE

    Diana Engelke; Bernd Oehme; Jens Strackeljan

    2011-01-01

    This paper concentrates on ultrasonic transducers, which are driven by piezoelectric ceramic rings that are arranged in a stack. A novel drive option, where the stack contains a new type of divided piezoelectric rings, is analyzed using the finite element method, prototyped, and tested. To gain a better sense of the vibration behavior, the studies focus initially on one ring and subsequently on the different possibilities to assemble the transducer. The investigations point out that natural b...

  17. Lead-Free Piezoelectric Transducers for Microelectronic Wirebonding Applications

    OpenAIRE

    Kwok, K.W.; T. Lee; Choy, S. H.; Chan, H.L.W.

    2010-01-01

    Lead-free KNLNTS and BNKLBT piezoelectric ceramic rings have been successfully prepared and used as the driving elements for fabricating ultrasonic wirebonding transducers. In order to improve the energy transfer between different parts of the transducer, titanium alloy has been used to fabricate the front and back plates. The dimensions of the ceramic rings and the titanium alloy plates have been optimized to give an operation frequency of 65 kHz. Because of the better matching of the acoust...

  18. Capacitive Ultrasonic Transducer Development for Acoustic Anemometry on Mars

    Science.gov (United States)

    Leonard-Pugh, Eurion; Wilson, C.; Calcutt, S.; Davis, L.

    2012-10-01

    Previous Mars missions have used either mechanical or thermal anemometry techniques. The moving parts of mechanical anemometers are prone to damage during launch and landing and their inertia makes them unsuited for turbulence studies. Thermal anemometers have been used successfully on Mars but are difficult to calibrate and susceptible to varying ambient temperatures. In ultrasonic anemometry, wind speed and sound speed are calculated from two-way time-of-flight measurements between pairs of transducers; three pairs of transducers are used to return a 3-D wind vector. These high-frequency measurements are highly reliable and immune from drift. Piezo-electric ultrasonic anemometers are widely used on Earth due to their full-range accuracy and high measurement frequency. However these transducers have high acoustic impedances and would not work on Mars. We are developing low-mass capacitive ultrasonic transducers for Mars missions which have significantly lower acoustic impedances and would therefore have a much stronger coupling to the Martian atmosphere. These transducers consist of a metallised polymer film pulled taught against a machined metal backplane. The film is drawn towards the backplane by a DC bias voltage. A varying signal is used on top of the DC bias to oscillate the film; generating acoustic waves. This poster will look at the operation of such sensors and the developments necessary to operate the devices under Martian conditions. Transducer performance is determined primarily by two elements; the front film and the backplane. The sensitivity of the transducer is affected by the thickness of the front film; as well as the diameter, curvature and roughness of the metal backplane. We present data on the performance of the sensors and instrument design considerations including signal shapes and transducer arrangements.

  19. Finite-State Complexity and the Size of Transducers

    Directory of Open Access Journals (Sweden)

    Cristian Calude

    2010-08-01

    Full Text Available Finite-state complexity is a variant of algorithmic information theory obtained by replacing Turing machines with finite transducers. We consider the state-size of transducers needed for minimal descriptions of arbitrary strings and, as our main result, we show that the state-size hierarchy with respect to a standard encoding is infinite. We consider also hierarchies yielded by more general computable encodings.

  20. Ionic solvents used in ionic polymer transducers, sensors and actuators

    OpenAIRE

    2004-01-01

    Ionic liquids are incorporated into transducers, actuators or sensors which employ the ionic polymer membranes. The ionic liquids have superior electrochemical stability, low viscosity and low vapor pressure. The transducers, actuators and sensors which utilize ionic polymer membranes solvated with ionic liquids have long term air stability. Superior results are achieved when a conductive powder and ionomer mixture is applied to the ionic polymer membrane to form the electrodes during or afte...

  1. Oblong-Shaped-Focused Transducers for Intravascular Ultrasound Imaging.

    Science.gov (United States)

    Lee, Junsu; Jang, Jihun; Chang, Jin Ho

    2017-03-01

    In intravascular ultrasound (IVUS) imaging, a transducer is inserted into a blood vessel and rotated to obtain image data. For this purpose, the transducer aperture is typically less than 0.5 mm in diameter, which causes natural focusing to occur in the imaging depth ranging from 1 to 5 mm. Due to the small aperture, however, it is not viable to conduct geometric focusing in order to enhance the spatial resolution of IVUS images. Furthermore, this hampers narrowing the slice thickness of a cross-sectional scan plane in the imaging depth, which leads to lowering spatial and contrast resolutions of IVUS images. To solve this problem, we propose an oblong-shaped-focused transducer for IVUS imaging. Unlike the conventional IVUS transducers with either a circular or a square flat aperture, the proposed transducer has an oblong aperture of which long side is positioned along a blood vessel. This unique configuration makes it possible to conduct geometric focusing at a desired depth in the elevation direction. In this study, furthermore, it is demonstrated that a spherically shaped aperture in both lateral and elevation directions also improves lateral resolution, compared to the conventional flat aperture. To ascertain this, the conventional and the proposed IVUS transducers were designed and fabricated to evaluate and to compare their imaging performances through wire phantom and tissue-mimicking phantom experiments. For the proposed 50-MHz IVUS transducer, a PZT piece of 0.5 × 1.0 mm(2) was spherically shaped for elevation focus at 3 mm by using the conventional press-focusing technique whereas the conventional one has a flat aperture of 0.5 × 0.5 mm(2). The experimental results demonstrated that the proposed IVUS transducer is capable of improving spatial and contrast resolutions of IVUS images.

  2. Method and apparatus for air-coupled transducer

    Science.gov (United States)

    Song, Junho (Inventor); Chimenti, Dale E. (Inventor)

    2010-01-01

    An air-coupled transducer includes a ultrasonic transducer body having a radiation end with a backing fixture at the radiation end. There is a flexible backplate conformingly fit to the backing fixture and a thin membrane (preferably a metallized polymer) conformingly fit to the flexible backplate. In one embodiment, the backing fixture is spherically curved and the flexible backplate is spherically curved. The flexible backplate is preferably patterned with pits or depressions.

  3. Micromachining of a piezocomposite transducer using a copper vapor laser.

    Science.gov (United States)

    Farlow, R; Galbraith, W; Knowles, M; Hayward, G

    2001-05-01

    A 1-3 piezocomposite transducer with front face dimensions of 2 x 2 mm has been micromachined using a copper vapor laser. The device consists of PZT5A piezoceramic pillars with a 65-micron pitch suspended in a low viscosity thermosetting polymer. The kerf width is 13 microns, and the transducer thickness is 170 microns, making the device suitable for ultrasonic reception at frequencies close to 10 MHz.

  4. Expression of the chemokine receptor CXCR7 in CXCR4-expressing human 143B osteosarcoma cells enhances lung metastasis of intratibial xenografts in SCID mice.

    Science.gov (United States)

    Brennecke, Patrick; Arlt, Matthias J E; Muff, Roman; Campanile, Carmen; Gvozdenovic, Ana; Husmann, Knut; Holzwarth, Nathalie; Cameroni, Elisabetta; Ehrensperger, Felix; Thelen, Marcus; Born, Walter; Fuchs, Bruno

    2013-01-01

    More effective treatment of metastasizing osteosarcoma with a current mean 5-year survival rate of less than 20% requires more detailed knowledge on mechanisms and key regulatory molecules of the complex metastatic process. CXCR4, the receptor of the chemokine CXCL12, has been reported to promote tumor progression and metastasis in osteosarcoma. CXCR7 is a recently deorphanized CXCL12-scavenging receptor with so far not well-defined functions in tumor biology. The present study focused on a potential malignancy enhancing function of CXCR7 in interaction with CXCR4 in osteosarcoma, which was investigated in an intratibial osteosarcoma model in SCID mice, making use of the human 143B osteosarcoma cell line that spontaneously metastasizes to the lung and expresses endogenous CXCR4. 143B osteosarcoma cells stably expressing LacZ (143B-LacZ cells) were retrovirally transduced with a gene encoding HA-tagged CXCR7 (143B-LacZ-X7-HA cells). 143B-LacZ-X7-HA cells co-expressing CXCR7 and CXCR4 exhibited CXCL12 scavenging and enhanced adhesion to IL-1β-activated HUVEC cells compared to 143B-LacZ cells expressing CXCR4 alone. SCID mice intratibially injected with 143B-LacZ-X7-HA cells had significantly (plung metastases than mice injected with 143B-LacZ cells. Unexpectedly, 143B-LacZ-X7-HA cells, unlike 143B-LacZ cells, also metastasized with high incidence to the auriculum cordis. In conclusion, expression of the CXCL12 scavenging receptor CXCR7 in the CXCR4-expressing human 143B osteosarcoma cell line enhances its metastatic activity in intratibial primary tumors in SCID mice that predominantly metastasize to the lung and thereby closely mimic the human disease. These findings point to CXCR7 as a target, complementary to previously proposed CXCR4, for more effective metastasis-suppressive treatment in osteosarcoma.

  5. An analytical model of a longitudinal-torsional ultrasonic transducer

    Science.gov (United States)

    Al-Budairi, Hassan; Lucas, Margaret

    2012-08-01

    The combination of longitudinal and torsional (LT) vibrations at high frequencies finds many applications such as ultrasonic drilling, ultrasonic welding, and ultrasonic motors. The LT mode can be obtained by modifications to the design of a standard bolted Langevin ultrasonic transducer driven by an axially poled piezoceramic stack, by a technique that degenerates the longitudinal mode to an LT motion by a geometrical alteration of the wave path. The transducer design is developed and optimised through numerical modelling which can represent the geometry and mechanical properties of the transducer and its vibration response to an electrical input applied across the piezoceramic stack. However, although these models can allow accurate descriptions of the mechanical behaviour, they do not generally provide adequate insights into the electrical characteristics of the transducer. In this work, an analytical model is developed to present the LT transducer based on the equivalent circuit method. This model can represent both the mechanical and electrical aspects and is used to extract many of the design parameters, such as resonance and anti-resonance frequencies, the impedance spectra and the coupling coefficient of the transducer. The validity of the analytical model is demonstrated by close agreement with experimental results.

  6. Exact series model of Langevin transducers with internal losses.

    Science.gov (United States)

    Nishamol, P A; Ebenezer, D D

    2014-03-01

    An exact series method is presented to analyze classical Langevin transducers with arbitrary boundary conditions. The transducers consist of an axially polarized piezoelectric solid cylinder sandwiched between two elastic solid cylinders. All three cylinders are of the same diameter. The length to diameter ratio is arbitrary. Complex piezoelectric and elastic coefficients are used to model internal losses. Solutions to the exact linearized governing equations for each cylinder include four series. Each term in each series is an exact solution to the governing equations. Bessel and trigonometric functions that form complete and orthogonal sets in the radial and axial directions, respectively, are used in the series. Asymmetric transducers and boundary conditions are modeled by using axially symmetric and anti-symmetric sets of functions. All interface and boundary conditions are satisfied in a weighted-average sense. The computed input electrical admittance, displacement, and stress in transducers are presented in tables and figures, and are in very good agreement with those obtained using atila-a finite element package for the analysis of sonar transducers. For all the transducers considered in the analysis, the maximum difference between the first three resonance frequencies calculated using the present method and atila is less than 0.03%.

  7. Software for Correcting the Dynamic Error of Force Transducers

    Directory of Open Access Journals (Sweden)

    Naoki Miyashita

    2014-07-01

    Full Text Available Software which corrects the dynamic error of force transducers in impact force measurements using their own output signal has been developed. The software corrects the output waveform of the transducers using the output waveform itself, estimates its uncertainty and displays the results. In the experiment, the dynamic error of three transducers of the same model are evaluated using the Levitation Mass Method (LMM, in which the impact forces applied to the transducers are accurately determined as the inertial force of the moving part of the aerostatic linear bearing. The parameters for correcting the dynamic error are determined from the results of one set of impact measurements of one transducer. Then, the validity of the obtained parameters is evaluated using the results of the other sets of measurements of all the three transducers. The uncertainties in the uncorrected force and those in the corrected force are also estimated. If manufacturers determine the correction parameters for each model using the proposed method, and provide the software with the parameters corresponding to each model, then users can obtain the waveform corrected against dynamic error and its uncertainty. The present status and the future prospects of the developed software are discussed in this paper.

  8. Microelectronics mounted on a piezoelectric transducer: method, simulations, and measurements.

    Science.gov (United States)

    Johansson, Jonny; Delsing, Jerker

    2006-01-01

    This paper describes the design of a highly integrated ultrasound sensor where the piezoelectric ceramic transducer is used as the carrier for the driver electronics. Intended as one part in a complete portable, battery operated ultrasound sensor system, focus has been to achieve small size and low power consumption. An optimized ASIC driver stage is mounted directly on the piezoelectric transducer and connected using wire bond technology. The absence of wiring between driver and transducer provides excellent pulse control possibilities and eliminates the need for broad band matching networks. Estimates of the sensor power consumption are made based on the capacitive behavior of the piezoelectric transducer. System behavior and power consumption are simulated using SPICE models of the ultrasound transducer together with transistor level modelling of the driver stage. Measurements and simulations are presented of system power consumption and echo energy in a pulse echo setup. It is shown that the power consumption varies with the excitation pulse width, which also affects the received ultrasound energy in a pulse echo setup. The measured power consumption for a 16 mm diameter 4.4 MHz piezoelectric transducer varies between 95 microW and 130 microW at a repetition frequency of 1 kHz. As a lower repetition frequency gives a linearly lower power consumption, very long battery operating times can be achieved. The measured results come very close to simulations as well as estimated ideal minimum power consumption.

  9. Study of the compact fiber optic photoacoustic ultrasonic transducer

    Science.gov (United States)

    Wu, Nan; Tian, Ye; Zou, Xiaotian; Wang, Xingwei

    2012-04-01

    Recently, many studies have been exerted on developing ultrasonic transducers that can feature high frequencies for better resolutions and compact sizes for the limit space nondestructive testing applications. Conventional ultrasonic transducers, which are made by piezoelectric materials, suffer from issues such as low frequencies and bulky sizes due to the difficulty of dicing piezoelectric materials into smaller pieces. On the other hand, generating ultrasonic signals by photoacoustic principle is a promising way to generate a high frequency ultrasonic pulse. Optical fiber is a very compact material that can carry the light energy. By combining the photoacoustic principle and the optical fiber together, a novel ultrasonic transducer that features a high frequency and a compact size could be achieved. In this paper, an ultrasonic transducer using gold nanoparticles as the photoacoustic generation material is described. Gold nanoparticles are deposited on the end surface of an optical fiber acting as the ultrasonic generator. A cavity and a diaphragm are fabricated in the center of the fiber using as the ultrasonic receiver. A phase array technique is applied to the transducer to steer the direction of the acoustic beam. Simulation results demonstrated that the photoacoustic ultrasonic transducer is feasible.

  10. Characterization of noncontact piezoelectric transducer with conically shaped piezoelement

    Science.gov (United States)

    Williams, James H., Jr.; Ochi, Simeon C. U.

    1988-01-01

    The characterization of a dynamic surface displacement transducer (IQI Model 501) by a noncontact method is presented. The transducer is designed for ultrasonic as well as acoustic emission measurements and, according to the manufacturer, its characteristic features include a flat frequency response range which is from 50 to 1000 kHz and a quality factor Q of less than unity. The characterization is based on the behavior of the transducer as a receiver and involves exciting the transducer directly by transient pulse input stress signals of quasi-electrostatic origin and observing its response in a digital storage oscilloscope. Theoretical models for studying the response of the transducer to pulse input stress signals and for generating pulse stress signals are presented. The characteristic features of the transducer which include the central frequency f sub o, quality factor Q, and flat frequency response range are obtained by this noncontact characterization technique and they compare favorably with those obtained by a tone burst method which are also presented.

  11. Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

    Science.gov (United States)

    Eriksson, Tobias J. R.; Laws, Michael; Kang, Lei; Fan, Yichao; Ramadas, Sivaram N.; Dixon, Steve

    2016-01-01

    Three designs for electrodynamic flexural transducers (EDFT) for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL) above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio (SNR)≃15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart. PMID:27571075

  12. Piezoelectric films for high frequency ultrasonic transducers in biomedical applications.

    Science.gov (United States)

    Zhou, Qifa; Lau, Sienting; Wu, Dawei; Shung, K Kirk

    2011-02-01

    Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the current status of the piezoelectric films and recent progress in the development of high frequency ultrasonic transducers will be discussed. Then details for preparation and structure of the materials derived from piezoelectric thick film technologies will be described. Both chemical and physical methods are included in the discussion, namely, the sol-gel approach, aerosol technology and hydrothermal method. The electric and piezoelectric properties of the piezoelectric films, which are very important for transducer applications, such as permittivity and electromechanical coupling factor, are also addressed. Finally, the recent developments in the high frequency transducers and arrays with piezoelectric ZnO and PZT thick film using MEMS technology are presented. In addition, current problems and further direction of the piezoelectric films for very high frequency ultrasound application (up to GHz) are also discussed.

  13. Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

    Science.gov (United States)

    Li, H.; Jung, K. W.; Deng, Z. D.

    2015-11-01

    Implantable acoustic transmitters have been used in the last 20 years to track fish movement for fish survival and migration behavior studies. However, the relatively large weights and sizes of commercial transmitters limit the populations of studied fish. The surgical implantation procedures may also affect fish adversely and incur a significant amount of labor. Therefore, a smaller, lighter, and injectable transmitter was needed, and similar or better acoustic performance and service life over those provided by existing commercial transmitters was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. Our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the signal was not blocked by the transmitter body. We found that a novel off-center tube transducer improved the average source level by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 1.3 dB. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. Lastly, a tuning inductor in series with the transducer was used to help optimize the source level. The findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.

  14. Analytical calibration of linear transducer arrays for photoacoustic tomography

    Science.gov (United States)

    Oeri, Milan; Bost, Wolfgang; Fournelle, Marc

    2015-07-01

    Tomographic photoacoustic imaging (PAT) allows to overcome the anisotropic image resolution of conventional reflection mode imaging. In order to achieve high-resolution, tomographic images, precise information on the position of each detector element is required. PAT systems that acquire signals from rotating linear transducer arrays come with inevitable transducer misalignments. Up to now, transducer orientation (x/y-tilt) and radial distance uncertainty were measured experimentally or have not been considered. Uncalibrated, these systems suffer from characteristic artifacts yielding misinterpretations of anatomic structures. Herein, we derive the artifact mathematically and investigate an analytical calibration method that enables the calculation and compensation of important transducer positioning parameters: the rotational radius and in-plane tilt. We studied the approach theoretically and evaluated the performance of the developed algorithm both on numerical and experimental data. A PAT system based on a 5-MHz linear transducer array, a multichannel electronics platform with channel data access, a NIR-emitting laser system and a rotating samples is used to demonstrate the benefit of the transducer calibration method providing isotropic resolution of 160 μm.

  15. Focusing of ferroelectret air-coupled ultrasound transducers

    Science.gov (United States)

    Gaal, Mate; Bartusch, Jürgen; Dohse, Elmar; Schadow, Florian; Köppe, Enrico

    2016-02-01

    Air-coupled ultrasound has been applied increasingly as a non-destructive testing method for lightweight construction in recent years. It is particularly appropriate for composite materials being used in automotive and aviation industry. Air-coupled ultrasound transducers mostly consist of piezoelectric materials and matching layers. However, their fabrication is challenging and their signal-to-noise ratio often not sufficient for many testing requirements. To enhance the efficiency, air-coupled ultrasound transducers made of cellular polypropylene have been developed. Because of its small density and sound velocity, this piezoelectric ferroelectret matches the small acoustic impedance of air much better than matching layers applied in conventional transducers. In our contribution, we present two different methods of spherical focusing of ferroelectret transducers for the further enhancement of their performance in NDT applications. Measurements on carbon-fiber-reinforced polymer (CFRP) samples and on metal adhesive joints performed with commercially available focused air-coupled ultrasound transducers are compared to measurements executed with self-developed focused ferroelectret transducers.

  16. Ultrasonic Transducers for Air and Underwater Communication.

    Science.gov (United States)

    Koosha, Abdolrahim

    Available from UMI in association with The British Library. The performance of a novel radiator capable of producing ultrasonic waves in air and liquids has been investigated. For commercial transducers when operating in air or liquids, impedance matching is the necessary condition for maximum transfer of energy to the medium (thus no standing waves are involved). However, for this radiator the formation of the mechanical standing waves on it is the key condition for directional radiation of energy into the surrounding environment. Under this condition the radiator exhibits a practical conversion of electrical energy into ultrasound. To further improve the performance of the radiator the wavelength coincidence condition must be satisfied. This condition implies that the wavelength of the bending vibration developed on the blade to be the same as that in the medium to which it is coupled. Consequently, an end-fire radiation pattern is obtained. The theory of this when applied to water and also for a double blade configuration are presented. The main component of the radiator consists of a cantilever blade on which a pair of piezoelectric (PZT) ceramic bars are fixed. These the so called excitation gauges, are fixed on both sides of a thin rectangular metal blade near the clamped end. When wavelength coincidence condition is fulfilled, the radiator transmits ultrasonic wave in a highly directional pattern. The direction of propagation of ultrasound is solely steered by frequency of the applied signal. System imperfections such as inter modal coupling when used underwater are considered. An analytical approach is developed to investigate the performance of the radiator for transmission of digital signals in air as well as in water. This method is used to evaluate the efficiency of the device as a suitable means for communication between divers or a diver and an underwater stationary station. Amplitude modulation of speech signals demonstrated the capabilities of a new

  17. Smoothened transduces Hedgehog signal by forming a complex with Evc/Evc2

    Institute of Scientific and Technical Information of China (English)

    Cuiping Yang; Wenlin Chen; Yongbin Chen; Jin Jiang

    2012-01-01

    Hedgehog (Hh) signaling plays pivotal roles in embryonic development and adult tissue homeostasis in species ranging from Drosophila to mammals.The Hh signal is transduced by Smoothened (Smo),a seven-transmembrane protein related to G protein coupled receptors.Despite a conserved mechanism by which Hh activates Smo in Drosophila and mammals,how mammalian Hh signal is transduced from Smo to the Gli transcription factors is poorly understood.Here,we provide evidence that two ciliary proteins,Evc and Evc2,the products of human disease genes responsible for the Ellis-van Creveld syndrome,act downstream of Smo to transduce the Hh signal.We found that loss of Evc/Evc2 does not affect Sonic Hedgehog-induced Smo phosphorylation and ciliary localization but impedes Hh pathway activation mediated by constitutively active forms of Smo.Evc/Evc2 are dispensable for the constitutive Gli activity in Sufu-/- cells,suggesting that Evc/Evc2 act upstream of Sufu to promote Gli activation.Furthermore,we demonstrated that Hh stimulates binding of Evc/Evc2 to Smo depending on phosphorylation of the Smo C-terminal intracellular tail and that the binding is abolished in Kif3a-/- cilium-deficient cells.We propose that Hh activates Smo by inducing its phosphorylation,which recruits Evc/Evc2 to activate Gli proteins by antagonizing Sufu in the primary cilia.

  18. Smoothened transduces Hedgehog signal by forming a complex with Evc/Evc2.

    Science.gov (United States)

    Yang, Cuiping; Chen, Wenlin; Chen, Yongbin; Jiang, Jin

    2012-11-01

    Hedgehog (Hh) signaling plays pivotal roles in embryonic development and adult tissue homeostasis in species ranging from Drosophila to mammals. The Hh signal is transduced by Smoothened (Smo), a seven-transmembrane protein related to G protein coupled receptors. Despite a conserved mechanism by which Hh activates Smo in Drosophila and mammals, how mammalian Hh signal is transduced from Smo to the Gli transcription factors is poorly understood. Here, we provide evidence that two ciliary proteins, Evc and Evc2, the products of human disease genes responsible for the Ellis-van Creveld syndrome, act downstream of Smo to transduce the Hh signal. We found that loss of Evc/Evc2 does not affect Sonic Hedgehog-induced Smo phosphorylation and ciliary localization but impedes Hh pathway activation mediated by constitutively active forms of Smo. Evc/Evc2 are dispensable for the constitutive Gli activity in Sufu(-/-) cells, suggesting that Evc/Evc2 act upstream of Sufu to promote Gli activation. Furthermore, we demonstrated that Hh stimulates binding of Evc/Evc2 to Smo depending on phosphorylation of the Smo C-terminal intracellular tail and that the binding is abolished in Kif3a(-/-) cilium-deficient cells. We propose that Hh activates Smo by inducing its phosphorylation, which recruits Evc/Evc2 to activate Gli proteins by antagonizing Sufu in the primary cilia.

  19. Expression of a model gene in prostate cancer cells lentivirally transduced in vitro and in vivo.

    Science.gov (United States)

    Bastide, C; Maroc, N; Bladou, F; Hassoun, J; Maitland, N; Mannoni, P; Bagnis, C

    2003-01-01

    In a preclinical model for prostate cancer gene therapy, we have tested lentiviral vectors as a practical possibility for the transfer and long-term expression of the EGFP gene both in vitro and in vivo. The human prostate cancer cell lines DU145 and PC3 were transduced using experimental conditions which permitted analysis of the expression from a single proviral vector per cell. The transduced cells stably expressed the EGFP transgene for 4 months. After injection of the transduced cell populations into Nod-SCID mice a decrease in EGFP was only observed in a minority of cases, while the majority of tumors maintained transgene expression at in vitro levels. In vivo injection of viral vector preparations directly into pre-established subcutaneous or orthotopic tumor masses, obtained by implantation of untransduced PC3 and DU145 cells led to a high transduction efficiency. While the efficiency of direct intratumoral transduction was proportional to the dose of virus injected, the results indicated some technical limitations inherent in these approaches to prostate cancer gene therapy.

  20. A bioanalytical microsystem for protein and DNA sensing based on a monolithic silicon optoelectronic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Misiakos, K [Microelectronics Institute, NCSR ' Demokritos' , 15310, Athens (Greece); Petrou, P S [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Kakabakos, S E [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Ruf, H H [Fraunhofer Institute of Biomedical Engineering (IBMT) and University of Saarland, 66386, St Ingbert (Germany); Ehrentreich-Foerster, E [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany); Bier, F F [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany)

    2005-01-01

    A bioanalytical microsystem that is based on a monolithic silicon optical transducer and a microfluidic module and it is appropriate for real-time sensing of either DNA or protein analytes is presented. The optical transducer monolithically integrates silicon avalanche diodes as light sources, silicon nitride optical fibers and detectors and efficiently intercouples these optical elements through a self-alignment technique. After hydrophilization and silanization of the transducer surface, the biomolecular probes are immobilized through physical adsorption. Detection is performed through reaction of the immobilized biomolecules with gold nanoparticle labeled counterpart molecules. The binding of these molecules within the evanescent field at the surface of the optical fiber cause attenuated total reflection of the waveguided modes and reduction of the detector photocurrent. Using the developed microsystem, determination of single nucleotide polymorphism (SNP) in the gene of the human phenol sulfotransferase SULT1A1 was achieved. Full-matching hybrid resulted in 4-5 times higher signals compared to the mismatched hybrid after hybridization and dissociation processes. The protein sensing abilities of the developed microsystem were also investigated through a non-competitive assay for the determination of the MB isoform of creatine kinase enzyme (CK-MB) that is a widely used cardiac marker.

  1. Ultrasonic transducer chip assembly, ultrasound probe, ultrasonic imaging system and ultrasound assembly and probe manufacturing methods

    NARCIS (Netherlands)

    Weekamp, J.W.; Henneken, V.A.; Groenland, A.W.; Louwerse, M.C.

    2015-01-01

    Disclosed is an ultrasonic transducer assembly comprising an ultrasonic transducer chip (100) having a main surface comprising a plurality of ultrasound transducer elements (112) and a plurality of first contacts (120) for connecting to said ultrasound transducer elements; a contact chip (400) havin

  2. Ultrasonic flowmeters: temperature gradients and transducer geometry effects.

    Science.gov (United States)

    Willatzen, M

    2003-03-01

    Ultrasonic flowmeter performance is addressed for the case of cylindrically shaped flowmeters employing two reciprocal ultrasonic transducers A and B so as to measure time-of-flight differences between signals transmitted from transducer A towards B followed by an equivalent signal transmitted from transducer B towards A. In the case where a liquid flows through the flowmeter's measuring section ("spoolpiece"), the arrival times of the two signals differ by an amount related to the flow passing between the two transducers. Firstly, a detailed study of flow measurement errors with mean flow in the laminar flow regime is carried out as a function of the mode index and the transducer diameter/cylinder diameter ratio in the case where no temperature gradients are present in the flowmeter sensor. It is shown that all modes except the fundamental mode overestimate the mean flow by a factor of 33.33% while excitation of the fundamental mode solely give error-free measurements. The immediate consequences are that the flowmeter error decreases as the transducer diameter/cylinder diameter ratio approaches 1 from 0 reflecting the fact that the excitation level of the fundamental mode increases from almost 0 to 1 as this ratio approaches 1 from 0. Secondly, the effect on flowmeter performance due to flow-induced temperature gradients is examined. It is shown that the presence of temperature gradients leads to flowmeter errors at the higher-flow values even in the case where the fundamental mode is the only mode excited. It is also deduced that flowmeter errors in general depend on the distance between transducers A and B whether temperature gradients exist or not. This conclusion is not reflected in the usual definition of flowmeter errors given by the so-called mode-dependent deviation of measurement introduced in earlier works.

  3. Transducer-binding and transducer-mutations modulate photoactive-site-deprotonation in sensory rhodopsin I.

    Science.gov (United States)

    Jung, K H; Spudich, E N; Dag, P; Spudich, J L

    1999-10-05

    Sensory rhodopsin I (SRI) is a seven-transmembrane helix retinylidene protein that mediates color-sensitive phototaxis responses through its bound transducer HtrI in the archaeon Halobacterium salinarum. Deprotonation of the Schiff base attachment site of the chromophore accompanies formation of the SRI signaling state, S(373). We measured the rate of laser flash-induced S(373) formation in the presence and absence of HtrI, and the effects of mutations in SRI or HtrI on the kinetics of this process. In the absence of HtrI, deprotonation occurs rapidly (halftime 10 micros) if the proton acceptor Asp76 is ionized (pK(a) = approximately 7), and only very slowly (halftime > 10 ms) when Asp76 is protonated. Transducer-binding, although it increases the pK(a) of Asp76 so that it is protonated throughout the range of pH studied, results in a first order, pH-independent rate of S(373) formation of approximately 300 micros. Therefore, the complexation of HtrI facilitates the proton-transfer reaction, increasing the rate approximately 50-fold at pH6. Arrhenius analysis shows that HtrI-binding accelerates the reaction primarily by an entropic effect, suggesting HtrI constrains the SRI molecule in the complex. Function-perturbing mutations in SRI and HtrI also alter the rate of S(373) formation and the lambda(max) of the parent state as assessed by laser flash-induced kinetic difference spectroscopy, and shifts to longer wavelength are correlated with slower deprotonation. The data indicate that HtrI affects electrostatic interactions of the protonated Schiff base and not only receives the signal from SRI but also optimizes the photochemical reaction process for SRI signaling.

  4. Complexes between nuclear factor-κB p65 and signal transducer and activator of transcription 3 are key actors in inducing activation-induced cytidine deaminase expression and immunoglobulin A production in CD40L plus interleukin-10-treated human blood B cells.

    Science.gov (United States)

    Lafarge, S; Hamzeh-Cognasse, H; Richard, Y; Pozzetto, B; Cogné, M; Cognasse, F; Garraud, O

    2011-11-01

    The signal transducer and activator of transcription 3 (STAT3) transcription factor pathway plays an important role in many biological phenomena. STAT3 transcription is triggered by cytokine-associated signals. Here, we use isolated human B cells to analyse the role of STAT3 in interleukin (IL)-10 induced terminal B cell differentiation and in immunoglobulin (Ig)A production as a characteristic readout of IL-10 signalling. We identified optimal conditions for inducing in-vitro IgA production by purified blood naive B cells using IL-10 and soluble CD40L. We show that soluble CD40L consistently induces the phosphorylation of nuclear factor (NF)-κB p65 but not of STAT3, while IL-10 induces the phosphorylation of STAT3 but not of NF-κB p65. Interestingly, while soluble CD40L and IL-10 were synergistic in driving the terminal maturation of B cells into IgA-producing plasma cells, they did not co-operate earlier in the pathway with regard to the transcription factors NF-κB p65 or STAT3. Blocking either NF-κB p65 or STAT3 profoundly altered the production of IgA and mRNA for activation-induced cytidine deaminase (AID), an enzyme strictly necessary for Ig heavy chain recombination. Finally, the STAT3 pathway was directly activated by IL-10, while IL-6, the main cytokine otherwise known for activating the STAT3 pathway, did not appear to be involved in IL-10-induced-STAT3 activation. Our results suggest that STAT3 and NF-κB pathways co-operate in IgA production, with soluble CD40L rapidly activating the NF-κB pathway, probably rendering STAT3 probably more reactive to IL-10 signalling. This novel role for STAT3 in B cell development reveals a potential therapeutic or vaccine target for eliciting IgA humoral responses at mucosal interfaces.

  5. 1-3 Piezocomposite transducers for AUV applications

    Science.gov (United States)

    Pazol, Brian; Lannaman, Ken; Doust, Barry

    2001-05-01

    Sonar systems on board AUVs present interesting challenges to the transducer designer because of their small size, low weight requirements, and limited available power. 1-3 piezocomposite transducers offer many performance characteristics which make them ideal for deployment in AUVs. Piezocomposite transducers are light weight, have broad bandwidth, have high efficiency, and can be conformed to fit the curvature of the vehicle. The broad bandwidths and low sidelobes made possible by piezocomposites result in sharper images with less distortion. The piezocomposite material is mechanically robust and can survive the rigors of normal operations as well as AUV deployment and retrieval. In addition, the conformal configuration substantially reduces hydrodynamic drag. As a conformal array, there is nothing to get knocked off during deployment and retrieval operations, or entangled with natural or man-made objects suspended in the water column. This contributes directly to improving the operational endurance of the AUV system, thereby enhancing overall system utility. MSI has produced and tested a variety of piezocomposite transducers for use in obstacle avoidance, mine hunting, and acoustic communications. An overview of piezocomposites and recent results of piezocomposite transducers will be presented.

  6. A cylindrical standing wave ultrasonic motor using bending vibration transducer.

    Science.gov (United States)

    Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

    2011-07-01

    A cylindrical standing wave ultrasonic motor using bending vibration transducer was proposed in this paper. The proposed stator contains a cylinder and a bending vibration transducer. The two combining sites between the cylinder and the transducer locate at the adjacent wave loops of bending vibration of the transducer and have a distance that equal to the half wave length of bending standing wave excited in the cylinder. Thus, the bending mode of the cylinder can be excited by the bending vibration of the transducer. Two circular cone type rotors are pressed in contact to the end rims of the teeth, and the preload between the rotors and stator is accomplished by a spring and nut system. The working principle of the proposed motor was analyzed. The motion trajectories of teeth were deduced. The stator was designed and analyzed with FEM. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 165rpm and maximum torque of 0.45Nm at an exciting voltage of 200V(rms).

  7. Delimitation of the lung region with distributed ultrasound transducers

    Science.gov (United States)

    Cardona Cárdenas, Diego Armando; Furuie, Sérgio Shiguemi

    2016-04-01

    One technique used to infer and monitor patient's respiratory conditions is the electrical impedance tomography (EIT). This provides images with information about lung function. The EIT image contrast is dependent on the variation of electrical impedance, therefore, this image does not provide anatomical details in border regions of several organs. To contribute to a clinical solution, we propose a new method to delimit regions of interest such as the pulmonary region and to improve the reconstruction quality of the EIT. Using a Matlab Toolbox k-wave, the ultrasound propagation phenomenon in homogeneous medium without patient (Reference) and with thoracic models were simulated, separately via a set of several ultrasound transducers distributed around the chest. After pulse emission by a transducer (TR), all received signals were compared considering the two sets of signals. If the energy relation between parts of the signals does not exceed an empirical threshold (30% in this study), a partial mask is generated between the transmitter and the receptor. This process was repeated until all 128 transducers are considered as TR-emitters. The 128 transducers (150kHz) are uniformly distributed. The evaluation was made by visually comparing the resulting images with the respective simulated object. A simple approach was presented to delimit high contrast organs with ultrasound transducers distributed around the patient. This approach allows other lower contrast objects to become invisible by varying the threshold limit. The investigation, based on numerical simulations of ultrasonic propagation, has shown promising results in the delimitation of the pulmonary region.

  8. Wideband Tonpilz Transducer with a Cavity Inside a Head Mass

    Science.gov (United States)

    Saosometh Chhith,; Yongrae Roh,

    2010-07-01

    A multimode Tonpilz transducer is well-known for providing a wider bandwidth than a single-mode transducer. In this paper, a new structure for the head mass of a multimode Tonpilz transducer was designed to further widen the bandwidth. The mechanical quality factor of a Tonpilz transducer is proportional to the weight of its head mass. In that sense, making the cavity inside the head mass will surely lead to a much lighter head mass, which can lead to a lower mechanical quality factor, thus a wider bandwidth. Through finite element analyses, the effects of the void head mass structure on the transducer performance were analyzed, and the dimension of the cavity to achieve the widest bandwidth was determined within given structural variation ranges. The variation ranges were selected as those in which the coefficient of determination in regression analyses was larger than 0.95 over all the ranges. The structure of a tail mass was also designed using the same method to match the new head mass.

  9. A hybrid transducer to magnetically and ultrasonically evaluate magnetic fluids.

    Science.gov (United States)

    Bruno, Alexandre Colello; Pavan, Théo Z; Baffa, Oswaldo; Carneiro, Antonio Adilton Oliveira

    2013-09-01

    Ultrasound, magnetic fields, and optical techniques have been explored for clinical diagnosis and therapy. However, these techniques have limitations. In this study, we constructed and characterized a transducer to magnetically and ultrasonically investigate samples labeled with magnetic particles. The transducer is a hybrid system consisting of an ac biosusceptometer (ACB) and an ultrasonic transducer. The basic operation principle consisted of measuring the magnetization and microvibrations of ferromagnetic particles (37 and 70 μm) mixed in yogurt and excited by an external alternating magnetic field generated by the ACB's excitation coils. The vibration of the ferromagnetic particles was measured in phantoms using a Doppler ultrasonic transducer; we verified the sensitivity to detecting the vibrations at low concentrations of ferromagnetic material (~1%). The responses of the susceptometer and Doppler ultrasound linearly depended on the voltage level applied to the magnetizing coils at low ferromagnetic particle concentrations (⩽ 5%). We also conducted a repeatability test on the prototype, which indicated a deviation of 0.94% and 0.25% in the Doppler and susceptometric measurements, respectively. We can conclude that the hybrid transducer technique has potential clinical applications.

  10. A highly sensitive fiber Bragg grating diaphragm pressure transducer

    Science.gov (United States)

    Allwood, Gary; Wild, Graham; Lubansky, Alex; Hinckley, Steven

    2015-10-01

    In this work, a novel diaphragm based pressure transducer with high sensitivity is described, including the physical design structure, in-depth analysis of optical response to changes in pressure, and a discussion of practical implementation and limitations. A flat circular rubber membrane bonded to a cylinder forms the body of the transducer. A fiber Bragg grating bonded to the center of the diaphragm structure enables the fractional change in pressure to be determined by analyzing the change in Bragg wavelength of the reflected spectra. Extensive evaluation of the physical properties and optical characteristics of the transducer has been performed through experimentation, and modeling using small deformation theory. The results show the transducer has a sensitivity of 0.116 nm/kPa, across a range of 15 kPa. Ultra-low cost interrogation of the optical signal was achieved through the use of an optically mismatched Bragg grating acting as an edge filter to convert the spectral change into an intensity change. A numerical model of the intensity based interrogation was implemented in order to validate the experimental results. Utilizing this interrogation technique and housing both the sensing and reference Bragg gratings within the main body of the transducer means it is effectively temperature insensitive and easily connected to electronic systems.

  11. Insertion and deletion mutagenesis of the human cytomegalovirus genome

    Energy Technology Data Exchange (ETDEWEB)

    Spaete, R.R.; Mocarski, E.S.

    1987-10-01

    Studies on human cytomegalovirus (CMV) have been limited by a paucity of molecular genetic techniques available for manipulating the viral genome. The authors have developed methods for site-specific insertion and deletion mutagenesis of CMV utilizing a modified Escherichia coli lacZ gene as a genetic marker. The lacZ gene was placed under the control of the major ..beta.. gene regulatory signals and inserted into the viral genome by homologous recombination, disrupting one of two copies of this ..beta.. gene within the L-component repeats of CMV DNA. They observed high-level expression of ..beta..-galactosidase by the recombinant in a temporally authentic manner, with levels of this enzyme approaching 1% of total protein in infected cells. Thus, CMV is an efficient vector for high-level expression of foreign gene products in human cells. Using back selection of lacZ-deficient virus in the presence of the chromogenic substrate 5-bromo-4-chloro-3-indolyl ..beta..-D-galactoside, they generated random endpoint deletion mutants. Analysis of these mutant revealed that CMV DNA sequences flanking the insert had been removed, thereby establishing this approach as a means of determining whether sequences flanking a lacZ insertion are dispensable for viral growth. In an initial test of the methods, they have shown that 7800 base pairs of one copy of L-component repeat sequences can be deleted without affecting viral growth in human fibroblasts.

  12. Confocal acoustic radiation force optical coherence elastography using a ring ultrasonic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Wenjuan [Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612 (United States); Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, California 92697 (United States); Li, Rui [Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612 (United States); Ma, Teng; Kirk Shung, K.; Zhou, Qifa [Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California 90089 (United States); Chen, Zhongping, E-mail: z2chen@uci.edu [Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612 (United States); Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, California 92697 (United States); Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697 (United States)

    2014-03-24

    We designed and developed a confocal acoustic radiation force optical coherence elastography system. A ring ultrasound transducer was used to achieve reflection mode excitation and generate an oscillating acoustic radiation force in order to generate displacements within the tissue, which were detected using the phase-resolved optical coherence elastography method. Both phantom and human tissue tests indicate that this system is able to sense the stiffness difference of samples and quantitatively map the elastic property of materials. Our confocal setup promises a great potential for point by point elastic imaging in vivo and differentiation of diseased tissues from normal tissue.

  13. Reducing the Effect of Transducer Mount Induced Noise on Aeroacoustic Wind Tunnel Testing Data with a New Transducer Mount Design

    Science.gov (United States)

    Herron, A. J.; Reed, D. K.; Nance, D. K.

    2015-01-01

    Characterization of launch vehicle unsteady aerodynamics is a field best studied through experimentation, which is often carried out in the form of large scale wind tunnel testing. Measurement of the fluctuating pressures induced by the boundary layer noise is customarily made with miniature pressure transducers installed into a model of the vehicle of interest. Literature shows that noise level increases between two to five decibels (dB referenced to 20 micropascal) can be induced when the transducer surface is not mounted perfectly flush with the model outer surface. To reduce this artificially induced noise, special transducer holders have been used for aeroacoustic wind tunnel testing by NASA. This holder is a sleeve into which the transducer fits, with a cap that allows it to be mounted in a recessed hole in the model. A single hole in the holder allows the transport of the tunnel medium so the transducer can discriminate the fluctuating pressure due to the turbulent boundary layer noise. The holder is first dry fitted into the model and any difference in height between the holder and the model surface can be sanded flush. The holder is then removed from the model, the transducer glued inside the holder, and the holder replaced in the model, secured also with glue, thus eliminating the problem of noise level increases due to lack of flushness. In order to work with this holder design, special transducers have been ordered with their standard screen removed and the diaphragm moved as close to the top of the casing as possible to minimize any cavity volume. Although this greatly reduces induced noise due to the transducers being out of flush, the holders can also induce a cavity resonance that is usually at a very high frequency. This noise is termed transducer mount induced noise (XMIN). The peak of the mode can vary with the cavity depth, boundary layer noise that can excite the mode, tunnel flow medium, and the build of the transducers. Because the boundary

  14. Energy harvesting with a slotted-cymbal transducer

    Institute of Scientific and Technical Information of China (English)

    Jiang-bo YUAN; Xiao-biao SHAN; Tao XIE; Wei-shan CHEN

    2009-01-01

    A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal endcaps. High circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input energy. Finite element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses, and reduce the loss of mechanical input energy that could be converted into electrical energy. In this letter, the performance of a slotted-cymbal transducer in energy harvesting was tested. The results show that the output voltage and power of the cymbal are improved. A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500kΩ resistive load, which is approximately 0.6 times more than that of the original cymbal transducer.

  15. A novel serrated columnar phased array ultrasonic transducer

    Science.gov (United States)

    Zou, Cheng; Sun, Zhenguo; Cai, Dong; Song, Hongwei; Chen, Qiang

    2016-02-01

    Traditionally, wedges are required to generate transverse waves in a solid specimen and mechanical rotation device is needed for interrogation of a specimen with a hollow bore, such as high speed railway locomotive axles, turbine rotors, etc. In order to eliminate the mechanical rotation process, a novel array pattern of phased array ultrasonic transducers named as serrated columnar phased array ultrasonic transducer (SCPAUT) is designed. The elementary transducers are planar rectangular, located on the outside surface of a cylinder. This layout is aimed to generate electrically rotating transverse waveforms so as to inspect the longitudinal cracks on the outside surface of a specimen which has a hollow bore at the center, such as the high speed railway locomotive axles. The general geometry of the SCPAUT and the inspection system are illustrated. A FEM model and mockup experiment has been carried out. The experiment results are in good agreement with the FEM simulation results.

  16. The Use of Phononic Crystals to Design Piezoelectric Power Transducers

    Directory of Open Access Journals (Sweden)

    Silvia Ronda

    2017-03-01

    Full Text Available It was recently proposed that the lateral resonances around the working resonance band of ultrasonic piezoelectric sandwich transducers can be stopped by a periodic array of circular holes drilled along the main propagation direction (a phononic crystal. In this work, the performance of different transducer designs made with this procedure is tested using laser vibrometry, electric impedance tests and finite element models (FEM. It is shown that in terms of mechanical vibration amplitude and acoustic efficiency, the best design for physiotherapy applications is when both, the piezoceramic and an aluminum capsule are phononic structures. The procedure described here can be applied to the design of power ultrasonic devices, physiotherapy transducers and other external medical power ultrasound applications where piston-like vibration in a narrow band is required.

  17. Design, production and testing of PMN-PT electrostrictive transducers.

    Science.gov (United States)

    Coutte, J; Dubus, B; Debus, J C; Granger, C; Jones, D

    2002-05-01

    Lead magnesium niobate ceramics (PMN) are promising materials for application in the field of high power transducers. The advantage of PMN materials are the large strains generated under moderate electric field and the low hysteresis. The electrostrictive effect is non-linear, the corresponding physical constants depend on temperature and frequency and a DC electrical bias is required. These difficulties must be considered at the design stage. A finite element model has been developed and validated in the ATILA code for non-linear static and time-domain analyses. These numerical modelings are used to design and test two Langevin-type electrostrictive transducers. The first transducer is made of PMN-PT-La (90-10-1%) ceramics (TRS Ceramics), the second one of ESCI ceramics (Morgan Matroc). For given static mechanical prestresses, resonance frequencies and effective coupling coefficients are measured at different DC electric fields and temperatures.

  18. Inter Digital Transducer Modelling through Mason Equivalent Circuit Model

    DEFF Research Database (Denmark)

    Mishra, Dipti; Singh, Abhishek; Hussain, Dil muhammed Akbar

    2016-01-01

    by Simulation program with Integrated Circuit Emphasis (HSPICE), a well-liked electronic path simulator. The acoustic wave devices are not suitable to simulation through circuit simulator.In this paper, an electrical model of Mason’s Equivalent electricalcircuit for an inter-digital transducer (IDT......The frequency reliance of inter-digital transducer is analyzed with the help of MASON’s Equivalent circuit which is based on Smith’s Equivalent circuit which is further based on Foster’sNetwork. An inter-digital transducer has been demonstratedas a RLC network. The circuit is simulated......) is projected which is well-suitedwith a broadlycast-offuniversalresolution circuit simulator SPICE built-in out with the proficiency to simulatethenegative capacitances and inductances. The investigationis done to prove the straightforwardness of establishing the frequency and time domain physical...

  19. Phased annular array transducers for ultrasonic guided wave applications

    Science.gov (United States)

    Yan, Fei; Borigo, Cody; Liang, Yue; Koduru, Jaya P.; Rose, Joseph L.

    2011-04-01

    Mode and frequency control always plays an important role in ultrasonic guided wave applications. In this paper, theoretical understanding of guided wave excitations of axisymmetric sources on plate structures is established. It is shown that a wave number spectrum can be used to investigate the guided wave excitations of an axisymmetric source. The wave number spectrum is calculated from a Hankel transform of the axial source loading profile. On the basis of the theoretical understanding, phased annular array transducers are developed as a powerful tool for guided wave mode and frequency control. By applying appropriate time delays to phase the multiple elements of an annular array transducer, guided wave mode and frequency tuning can be achieved fully electronically. The phased annular array transducers have been successfully used for various applications. Example applications presented in this paper include phased annular arrays for guided wave beamforming and a novel ultrasonic vibration modal analysis technique for damage detection.

  20. Some design considerations for small piezo-electrical ceramic transducers

    Science.gov (United States)

    Rijnja, H. A. J.

    1989-07-01

    The design parameters and the characteristics of small omnidirectional transducers, to be applied under water as projectors in the frequency range of about 1 kHz to 100 kHz and as hydrophones from very low frequencies up to again 100kHz are described. The transducers are constructed with piezoelectrical ceramic materials in the shape of hollow spheres, end capped tubes or piston (Tonpilz) elements. The highest source levels are obtained with spherical transducers as single omnidirectional sound sources. If larger arrays of sources are applied the array should be composed of single ended Tonpilz elements. The most sensitive receivers (hydrophones) are obtained with tangentially polarized end-capped tubes.

  1. Finite element analysis of piezoelectric underwater transducers for acoustic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hwan [Inha University, Incheon (Korea, Republic of); Kim, Heung Soo [Catholic University, Daegu (Korea, Republic of)

    2009-02-15

    This paper presents a simulation technique for analyzing acoustic characteristics of piezoelectric underwater transducers. A finite element method is adopted for modeling piezoelectric coupled problems including material damping and fluid-structure interaction problems by taking system matrices in complex form. For the finite element modeling of unbounded acoustic fluid, infinite wave envelope element (IWEE) is adopted to take into account the infinite domain. An in-house finite element program is developed and technical issues for implementing the program are explained. Using the simulation program, acoustic characteristics of tonpilz transducer are analyzed in terms of modal analysis, radiated pressure distribution, pressure spectrum, transmitting-voltage response and impedance analysis along with experimental comparison. The developed simulation technique can be used for designing ultrasonic transducers in the areas of nondestructive evaluation, underwater acoustics and bioengineering

  2. Actuators, transducers and motors based on giant magnetostrictive materials

    Energy Technology Data Exchange (ETDEWEB)

    Claeyssen, F.; Lhermet, N.; Le Letty, R. [Cedrat Recherche, Meylan (France); Bouchilloux, P. [Magsoft Corporation, 1223 People`s Avenue, New York 12180 (United States)

    1997-08-01

    Rare earth-iron magnetostrictive alloys, especially Terfenol-D, feature ``giant`` magnetostrains: static strains of 1000-2000 ppm and dynamic strains of 3500 ppm are reported. These strains permit building various actuating devices (actuators, transducers, motors) both at macro and micro scale. The object of the paper is to recall adapted design methods, especially finite element methods such as ATILA, and to review these different kinds of devices studied at Cedrat Recherche, providing both up-dated experimental and numerical results. The presented devices will include several large displacement longitudinal and shear actuators biased using permanent magnets and used either as characterisation devices or as electromechanical actuators (for active damping, for sonar transducers..), a 1 kHz 4 kW Tonpilz-type sonar transducer called the tripode, a 2 N m torque rotating multi-mode motor, a torsion based drift free micro actuator and a wireless linear micromotor. (orig.)

  3. INFLUENCE OF PIEZOELECTRIC TRANSDUCER TO GLASS FIBER REINFORCED COMPOSITE STIFFNESS

    Directory of Open Access Journals (Sweden)

    Witold Rządkowski

    2015-08-01

    Full Text Available The main goal was to determine if transducers based on piezoelectric materials are suitable for strain calculations in thin GFRP specimens. Numerous experimental studies, both physical and numerical, performed by the authors, have shown that there is a huge influence of bonded piezoelectric transducer on the overall stiffness of the measured object. The paper presents tensile test performed on strength machine with Digital Image Correlation strain and deflection observations. Test were compared with FEM models for detailed investigation. The main conclusion is piezoelectric transducers has huge influence on local stiffness of measured object. That is critical especially when they are used as strain sensors, when presence of sensor is influencing to measured results.

  4. Novice performance of ultrasound-guided needle advancement: standard 38-mm transducer vs 25-mm hockey stick transducer.

    Science.gov (United States)

    Davies, T; Townsley, P; Jlala, H; Dowling, M; Bedforth, N; Hardman, J G; McCahon, R A

    2012-08-01

    The optimal method to develop expertise in ultrasound-guided regional anaesthesia is unknown. Studies of laryngoscopic expertise in novices demonstrate that the choice of laryngoscope affects performance. In this study, we aimed to compare the effect of two different linear array transducers (38-mm standard vs 25-mm hockey stick) on novice performance of ultrasound-guided needle advancement. Following randomisation, participants watched a video model of expert performance of ultrasound-guided needle advancement. Recruits performed the modelled task on a turkey breast model. The median (IQR [range]) composite error score was statistically significantly larger for participants in the hockey stick transducer group compared with the standard transducer group; 10.0 (7.3-14.3 [2.5-29.0]) vs 7.5 (4.5-10.0 [2.0-28.0]) respectively, (p = 0.01). This study has demonstrated that performance of ultrasound-guided needle advancement by novice operators after simple video instruction is better (as assessed using a composite error score) with a standard 38-mm transducer than with a 25-mm hockey stick transducer. Anaesthesia © 2012 The Association of Anaesthetists of Great Britain and Ireland.

  5. High intensity ultrasound transducer used in gene transfection

    Science.gov (United States)

    Morrison, Kyle P.; Keilman, George W.; Noble, Misty L.; Brayman, Andrew A.; Miao, Carol H.

    2012-11-01

    This paper describes a novel therapeutic high intensity non-focused ultrasound (HIU) transducer designed with uniform pressure distribution to aid in accelerated gene transfer in large animal liver tissues in vivo. The underlying HIU transducer was used to initiate homogeneous cavitation throughout the tissue while delivering up to 2.7 MPa at 1.1 MHz across its radiating surface. The HIU transducer was built into a 6 cm diameter x 1.3 cm tall housing ergonomically designed to avoid collateral damage to the surrounding anatomy during dynamic motion. The ultrasound (US) radiation was applied in a 'paintbrush-like' manner to the surface of the liver. The layers and geometry of the transducer were carefully selected to maximize the active diameter (5.74 cm), maximize the electrical to acoustic conversion efficiency (85%) to achieve 2.7 MPa of peak negative pressure, maximize the frequency operating band at the fundamental resonance to within a power transfer delta of 1 dB, and reduce the pressure delta to within 2 dB across the radiating surface. For maximum peak voltage into the transducer, a high performance piezoceramic was chosen and a DC bias circuit was built integral to the system. An apodized two element annular pattern was made from a single piezoceramic element, resulting in significant pressure uniformity enhancement. In addition to using apodization for pressure uniformity, a proprietary multi-layered structure was used to improve efficiency while sustaining an operating band from 900 kHz to 1.3 MHz. The resultant operating band allowed for dithering techniques using frequency modulation. The underlying HIU transducer for use in large animals enhances gene expression up to 6300-fold.

  6. The planar silicon-based microelectronic technology for electrochemical transducers

    Science.gov (United States)

    Novikov, A. V.; Egorchikov, A. E.; Dolgov, A. N.; Gornev, E. S.; Popov, V. G.; Egorov, I. V.; Krishtop, V. G.

    2016-12-01

    We have developed the new technology for production of sensitive modules for electrochemical sensors of pressure and acceleration. The technology is applicable for mass production and scalable for high-volume production. In this work we demonstrate the new sensing module for electrochemical motion sensors, and its possibility of applying in geophones. We fabricated prototypes of electrochemical planar transducer chips, produced a laboratory prototype of a geophone based on our planar transducer chip, and tested them. This paper presents the preliminary results of the tests.

  7. Sensory TRP channels: the key transducers of nociception and pain.

    Science.gov (United States)

    Mickle, Aaron D; Shepherd, Andrew J; Mohapatra, Durga P

    2015-01-01

    Peripheral detection of nociceptive and painful stimuli by sensory neurons involves a complex repertoire of molecular detectors and/or transducers on distinct subsets of nerve fibers. The majority of such molecular detectors/transducers belong to the transient receptor potential (TRP) family of cation channels, which comprise both specific receptors for distinct nociceptive stimuli, as well as for multiple stimuli. This chapter discusses the classification, distribution, and functional properties of individual TRP channel types that have been implicated in various nociceptive and/or painful conditions.

  8. Simulating Capacitive Micromachined Ultrasonic Transducers (CMUTs) using Field II

    DEFF Research Database (Denmark)

    Bæk, David; Oralkan, Omer; Kupnik, Mario;

    2010-01-01

    Field II has been a recognized simulation tool for piezoceramic medical transducer arrays for more than a decade. The program has its strength in doing fast computations of the spatial impulse response (SIR) from array elements by dividing the elements into smaller mathematical elements (ME)s from...... which it calculates the SIR responses. The program features predefined models for classical transducer geometries, but currently none for the fast advancing CMUTs. This work addresses the assumptions required for modeling CMUTs with Field II. It is shown that rectangular array elements, populated...

  9. Effects of recombinant human growth hormone on tumor growth and access relevant to Janus kinase 2-signal transducer and activator of transcription 3 of human gastric carcinoma xenografts in nude mice%重组人生长激素对裸鼠人胃癌移植瘤组织生长及Janus激酶2-信号转导与转录激活因子3通路的影响

    Institute of Scientific and Technical Information of China (English)

    权明; 曹鹏; 李苏宜

    2011-01-01

    Objective To investigate the effects of recombinant human growth hormone (rhGH) on tumor growth and tumor angiogenesis factor relevant to Janus kinase 2-signal transducer and activator of transcription 3 of human gastric carcinoma xenografts in nude mice with different expressions of growth hormone receptor (GHR).Methods Immunocytochemical method was used to pick out one GHR-positive and one GHR-negative cell line. The cells were subcutaneously injected into 26 nude mice separately, then the patterns of xenografts in nude mice with different expressions of GHR were established. The nude mice bearing two different kinds of human gastric caicinoma were equally randomized into control group, low-dose rhGH group, and high-dose rhGH group,and were treated with drugs for 14 days. Changes of tumor volumes and body weight of nude mice were record. The protein and mRN A expressions of tumor angiogenesis factor in tumor tissue were detected by RT-PCR and Western blot, respectively. Results GHR was highly expressed in SGC-7901 celk but negative in MKN-45 cells. For nude mice bearing GHR+ SGC-7901 xenografts, the tumor volumes were significantly larger in low-dose rhGH group [(1. 141 ±0. 234) cm3] and high-dose rhGH group [(2. 106 ±0. 260) cm3] than in control group [(0.612±0. 156) cm3] (P = 0. 034, P = 0. 001), and the high-dose rhGH group revealed greater effect (P =0. 043 ). Body weight was not significantly different among three groups. Compared with the control group, the mRNA expressions of tumor angiogenesis factor were significantly increased in low-does rhGH group, and the P values of GHR, Janus kinase 2, signal transducer and activator of transcription 3, vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1α (HIF-1α), fibroblast growth factor, and matrix metalloproteinases-2 (MMP-2) was 0.001, 0.011, 0.042, 0.045, 0.040, 0.002, and 0.003, respectively; however, the high-does rhGH group did not show the greater effects. The protein expressions

  10. WT1-specific T cell receptor gene therapy: improving TCR function in transduced T cells.

    Science.gov (United States)

    Stauss, Hans J; Thomas, Sharyn; Cesco-Gaspere, Michela; Hart, Daniel P; Xue, Shao-An; Holler, Angelika; King, Judy; Wright, Graham; Perro, Mario; Pospori, Constantina; Morris, Emma

    2008-01-01

    Adoptive transfer of antigen-specific T lymphocytes is an attractive form of immunotherapy for haematological malignancies and cancer. The difficulty of isolating antigen-specific T lymphocytes for individual patients limits the more widespread use of adoptive T cell therapy. The demonstration that cloned T cell receptor (TCR) genes can be used to produce T lymphocyte populations of desired specificity offers new opportunities for antigen-specific T cell therapy. The first trial in humans demonstrated that TCR gene-modified T cells persisted for an extended time period and reduced tumor burden in some patients. The WT1 protein is an attractive target for immunotherapy of leukemia and solid cancer since elevated expression has been demonstrated in AML, CML, MDS and in breast, colon and ovarian cancer. In the past, we have isolated high avidity CTL specific for a WT1-derived peptide presented by HLA-A2 and cloned the TCR alpha and beta genes of a WT1-specific CTL line. The genes were inserted into retroviral vectors for transduction of human peripheral blood T lymphocytes of leukemia patients and normal donors. The treatment of leukemia-bearing NOD/SCID mice with T cells transduced with the WT1-specific TCR eliminated leukemia cells in the bone marrow of most mice, while treatment with T cells transduced with a TCR of irrelevant specificity did not diminish the leukemia burden. In order to improve the safety and efficacy of TCR gene therapy, we have developed lentiviral TCR gene transfer. In addition, we employed strategies to enhance TCR expression while avoiding TCR mis-pairing. It may be possible to generate dominant TCR constructs that can suppress the expression of the endogenous TCR on the surface of transduced T cells. The development of new TCR gene constructs holds great promise for the safe and effective delivery of TCR gene therapy for the treatment of malignancies.

  11. Analysis of eigenfrequencies in piezoelectric transducers using the finite element method

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1988-01-01

    It is noted that the finite-element method is a valuable supplement to the traditional methods for design of novel transducer types because it can determine the vibrational pattern of piezoelectric transducers and is applicable to any geometry. Computer programs for analysis of axisymmetric...... transducers, which include the complete set of piezoelectric equations, have been included. They can find eigenfrequencies for undamped transducers and perform forced-response analysis for transducers with internal and radiation damping. The superelement technique is used to model the transducer backing...

  12. Low-cost, high-power mechanical impact transducers for sonar and acoustic through-wall surveillance applications

    CERN Document Server

    Felber, Franklin

    2014-01-01

    A new concept is presented for mechanical acoustic transmitters and matched resonant receivers. The lightweight, compact, and low-cost transmitters produce high-power acoustic pulses at one or more discrete frequencies with very little input power. The transducer systems are well suited for coupling acoustic pulse energy into dense media, such as walls and water. Applications of the impact transducers are discussed, including detection and tracking of humans through walls and long-duration underwater surveillance by a low-cost network of autonomous, self-recharging, battery-operated sonobuoys. A conceptual design of a sonobuoy surveillance network for harbors and littoral waters is presented. An impact-transmitter and matched-receiver system that detected human motion through thick walls with only rudimentary signal processing is described, and results are presented. Signal processing methods for increasing the signal-to-noise ratio by several tens of dB are discussed.

  13. Investigation of capacitively coupled ultrasonic transducer system for nondestructive evaluation.

    Science.gov (United States)

    Zhong, Cheng Huan; Wilcox, Paul D; Croxford, Anthony J

    2013-12-01

    Capacitive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory, feasibility, and optimization of such a capacitively coupled transducer system (CCTS) in the context of nondestructive evaluation (NDE) applications. The noncontact interface relies on an electric field formed between four metal plates-two plates are physically connected to the electrodes of a transducer, the other two are in a separate probing unit connected to the transmit/receive channel of the instrumentation. The complete system is modeled as an electric network with the measured impedance of a bonded piezoelectric ceramic disc representing a transducer attached to an arbitrary solid substrate. A transmission line model is developed which is a function of the physical parameters of the capacitively coupled system, such as the permittivity of the material between the plates, the size of the metal plates, and their relative positions. This model provides immediate prediction of electric input impedance, pulse-echo response, and the effect of plate misalignment. The model has been validated experimentally and has enabled optimization of the various parameters. It is shown that placing a tuning inductor and series resistor on the transmitting side of the circuit can significantly improve the system performance in terms of the signal-to-crosstalk ratio. Practically, bulk-wave CCTSs have been built and demonstrated for underwater and through-composite testing. It has been found that electrical conduction in the media between the plates limits their applications.

  14. Inductively coupled transducer system for damage detection in composites

    Science.gov (United States)

    Zhong, C. H.; Croxford, A. J.; Wilcox, P. D.

    2012-04-01

    The laminated construction of composite offers the possibility of permanently embedding sensors into structure, for example, ultrasonic transducers which can be used for NDE applications. An attractive and simple solution for probing embedded sensors wirelessly is via inductive coupling. However, before this can be achieved it is necessary to have a full understanding and proper design strategy for the inductively coupled system. This paper presents the developments of both system design procedure and a computer program for one dimensional inductively coupled transducer system mounted on a solid substrate. The design strategy in this paper mainly focuses on issues of localization of transducers, and optimizing the signal to noise level. Starting from a three coil equivalent circuit, this paper also explains how the measured impedance of a bonded piezoelectric disc is implemented into the system model representing a transducer bonded to an arbitrary solid substrate. The computer programme using this model provides immediate predictions of electrical input impedance, acoustic response and pulse-echo response. A series of experiments and calculations have been performed in order to validate the model. This has enabled the degree of accuracy required for various parameters within the model, such as mutual inductance between the coils and self-inductance of coils, to be assessed. Once validated, the model can be used as a tool to predict the effect of physical parameters, such as distance, lateral misalignment between the coils, and the coil geometry on the performance of an inductively coupled system.

  15. High Temperature Ultrasonic Transducers : Material Selection and Testing

    Science.gov (United States)

    Bar-Cohen, Yoseph; Bruno, Alessandro

    2012-01-01

    The task of my two-months internship was to test different materials to be used to build an high temperature transducer, to develop some prototypes and to test their performance, to assess the reliability of commercial product rated for such a temperature, as well as to collaborate in developing the signal processing code to measure the condensed water levels.

  16. A Novel Rotary Piezoelectric Motor Using First Bending Hybrid Transducers

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    2015-08-01

    Full Text Available We report a novel rotary piezoelectric motor using bending transducers in this work. Three transducers are used to drive a disk-shaped rotor together by the elliptical movements of their driving tips; these motions are produced by the hybrid of two first bending vibration modes. The proposed piezoelectric transducer has a simple structure as it only contains an aluminum alloy beam and four pieces of PZT plates. Symmetrical structure is the only necessary condition in the design process as it will ensure the resonance frequencies of the two orthogonal first bending modes are equal. Transducers with first bending resonance frequency of about 53 kHz were fabricated and assembled into a rotary motor. The proposed motor exhibits good performance on speed and torque control. Under a working frequency of 53.2 kHz, the maximum no-load speed and the maximum torque of the prototype are tested to be 53.3 rpm and of 27 mN·m.

  17. Nonlinear Dynamic Modeling of Langevin-Type Piezoelectric Transducers

    Directory of Open Access Journals (Sweden)

    Nicolás Peréz Alvarez

    2015-11-01

    Full Text Available Langevin transducers are employed in several applications, such as power ultrasound systems, naval hydrophones, and high-displacement actuators. Nonlinear effects can influence their performance, especially at high vibration amplitude levels. These nonlinear effects produce variations in the resonant frequency, harmonics of the excitation frequency, in addition to loss of symmetry in the frequency response and “frequency domain hysteresis”. In this context, this paper presents a simplified nonlinear dynamic model of power ultrasound transducers requiring only two parameters for simulating the most relevant nonlinear effects. One parameter reproduces the changes in the resonance frequency and the other introduces the dependence of the frequency response on the history of the system. The piezoelectric constitutive equations are extended by a linear dependence of the elastic constant on the mechanical displacement amplitude. For introducing the frequency hysteresis, the elastic constant is computed by combining the current value of the mechanical amplitude with the previous state amplitude. The model developed in this work is applied for predicting the dynamic responses of a 26 kHz ultrasonic transducer. The comparison of theoretical and experimental responses, obtained at several input voltages around the tuned frequency, shows a good agreement, indicating that the model can accurately describe the transducer nonlinear behavior.

  18. Transverse Mode Multi-Resonant Single Crystal Transducer

    Science.gov (United States)

    Snook, Kevin A. (Inventor); Liang, Yu (Inventor); Luo, Jun (Inventor); Hackenberger, Wesley S. (Inventor); Sahul, Raffi (Inventor)

    2015-01-01

    A transducer is disclosed that includes a multiply resonant composite, the composite having a resonator bar of a piezoelectric single crystal configured in a d(sub 32) transverse length-extensional resonance mode having a crystallographic orientation set such that the thickness axis is in the (110) family and resonance direction is the (001) family.

  19. A distributed transducer system for functional electrical stimulation

    DEFF Research Database (Denmark)

    Gudnason, Gunnar; Nielsen, Jannik Hammel; Bruun, Erik

    2001-01-01

    Implanted transducers for functional electrical stimulation (FES) powered by inductive links are subject to conflicting requirements arising from low link efficiency, a low power budget and the need for protection of the weak signals against strong RF electromagnetic fields. We propose a solution...

  20. A capacitive ultrasonic transducer based on parametric resonance

    Science.gov (United States)

    Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F.

    2017-07-01

    A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

  1. Two methods for absolute calibration of dynamic pressure transducers

    Science.gov (United States)

    Swift, G. W.; Migliori, A.; Garrett, S. L.; Wheatley, J. C.

    1982-12-01

    Two techniques are described for absolute calibration of a dynamic pressure transducer from 0 to 400 Hz in 1-MPa helium gas. One technique is based on a comparison to a mercury manometer; the other is based on the principle of reciprocity. The two techniques agree within the instrumental uncertainties of 1%.

  2. Physical and chemical sensing using monolithic semiconductor optical transducers

    Science.gov (United States)

    Zappe, Hans P.; Hofstetter, Daniel; Maisenhoelder, Bernd; Moser, Michael; Riel, Peter; Kunz, Rino E.

    1997-09-01

    We present two monolithically integrated optical sensor systems based on semiconductor photonic integrated circuits. These compact, robust and highly functional transducers perform all necessary optical and electro-optical functions on-chip; extension to multi-sensor arrays is easily envisaged. A monolithic Michelson interferometer for high-resolution displacement measurement and a monolithic Mach-Zehnder interferometer for refractometry are discussed.

  3. Cooling method prolongs life of hot-wire transducer

    Science.gov (United States)

    Baldwin, L. V.; Sandborn, V. A.

    1964-01-01

    To cool a hot-wire transducer, the two ends of the wire are supported on thermally and electrically conductive rods, surrounded by a fluid cooling medium. By keeping the supporting rods at a substantially constant temperature, the probe is prevented from overheating.

  4. Neutron Irradiation Tests of Pressure Transducers in Liquid Helium

    CERN Document Server

    Amand, J F; Casas-Cubillos, J; Thermeau, J P

    1999-01-01

    The superconducting magnets of the future Large Hadron Collider (LHC) at CERN will operate in pressurised superfluid helium (1 bar, 1.9 K). About 500 pressure transducers will be placed in the liquid helium bath for monitoring the filling and the pressure transients after resistive transitions. Their precision must remain better than 100 mbar at pressures below 2 bar and better than 5% for higher pressures (up to 20 bar), with temperatures ranging from 1.8 K to 300 K. All the tested transducers are based on the same principle: the fluid or gas is separated from a sealed reference vacuum by an elastic membrane; its deformation indicates the pressure. The transducers will be exposed to high neutron fluence (2 kGy, 1014 n/cm2 per year) during the 20 years of machine operation. This irradiation may induce changes both on the membranes characteristics (leakage, modification of elasticity) and on gauges which measure their deformations. To investigate these effects and select the transducer to be used in the LHC, a...

  5. Acoustic impedance matching of piezoelectric transducers to the air.

    Science.gov (United States)

    Gómez Alvarez-Arenas, Tomás E

    2004-05-01

    The purpose of this work is threefold: to investigate material requirements to produce impedance matching layers for air-coupled piezoelectric transducers, to identify materials that meet these requirements, and to propose the best solution to produce air-coupled piezoelectric transducers for the low megahertz frequency range. Toward this end, design criteria for the matching layers and possible configurations are reviewed. Among the several factors that affect the efficiency of the matching layer, the importance of attenuation is pointed out. A standard characterization procedure is applied to a wide collection of candidate materials to produce matching layers. In particular, some types of filtration membranes are studied. From these results, the best materials are identified, and the better matching configuration is proposed. Four pairs of air-coupled piezoelectric transducers also are produced to illustrate the performance of the proposed solution. The lowest two-way insertion loss figure is -24 dB obtained at 0.45 MHz. This increases for higher frequency transducers up to -42 dB at 1.8 MHz and -50 at 2.25 MHz. Typical bandwidth is about 15-20%.

  6. Interdigitated interdigital transducer for surface elastometry of soft damping tissue.

    Science.gov (United States)

    Danicki, Eugene; Nowicki, Andrzej; Tasinkevych, Yuriy

    2013-06-01

    Measurement of the shear elastic constant of soft and highly damping tissue of high Poisson ratio is quite a challenging task. It is proposed to evaluate shear wave velocity and damping of tissue by measuring the shear skimming bulk waves using one interdigitated interdigital transducer on a piezoelectric layer, such as polyvinylidene fluoride, applied to the surface of the small tissue sample.

  7. Cantilever deflection measurement and actuation by an nterdigitated transducer

    NARCIS (Netherlands)

    Strambini, E.; Piazza, V.; Pingue, P.; Biasiol, G.; Sorba, L.; Beltram, F.

    2010-01-01

    A scheme that allows all-electrical high-bandwidth readout of a cantilever deflection by means of an integrated interdigitated transducer is presented. The present approach takes advantage of the piezoelectricity of the chosen cantilever substrate material to generate and detect surface-acoustic-wav

  8. Multilayer piezoelectric transducer models combined with Field II

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten; Jensen, Jørgen Arendt

    2012-01-01

    with a polymer ring, and submerged into water. The transducer models are developed to account for any external electrical loading impedance in the driving circuit. The models are adapted to calculate the surface acceleration needed by the Field II software in predicting pressure pulses at any location in front...

  9. Multilevel inverter based class D audio amplifier for capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    The reduced semiconductor voltage stress makes the multilevel inverters especially interesting, when driving capacitive transducers for audio applications. A ± 300 V flying capacitor class D audio amplifier driving a 100 nF load in the midrange region of 0.1-3.5 kHz with Total Harmonic Distortion...

  10. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    Science.gov (United States)

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect.

  11. Investigation of inductively coupled ultrasonic transducer system for NDE.

    Science.gov (United States)

    Zhong, Cheng Huan; Croxford, Anthony J; Wilcox, Paul D

    2013-06-01

    Inductive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such an inductively coupled transducer system in the context of nondestructive evaluation (NDE) applications. The noncontact interface is based on electromagnetic coupling between three coils; one of the coils is physically connected to the transducer, the other two are in a separate probing unit, where they are connected to the transmit and receive channels of the instrumentation. The complete system is modeled as a three-port network with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate. The developed transmission line model is a function of the physical parameters of the electromagnetic system, such as the number of turns and diameter of each coil, and their separation. This model provides immediate predictions of electrical input impedance and pulse-echo response. The model has been validated experimentally and a sensitivity analysis of the input parameters performed. This has enabled optimization of the various parameters. Inductively coupled transducer systems have been built for both bulk and guided wave examples. By using chirped excitation and baseline subtraction, inspection distance of up to 700 mm is achieved in single-shot, guided-wave pulse-echo mode measurements with a 5 mm separation between the probing coils and transducer coil on an aluminum plate structure. In the bulk wave example, a delamination in an 8.9-mm-thick carbon fiber composite specimen is successfully identified from the changes in the arrival time of a reflected pulse.

  12. A novel CMOS transducer for giant magnetoresistance sensors

    Science.gov (United States)

    Luong, Van Su; Lu, Chih-Cheng; Yang, Jing-Wen; Jeng, Jen-Tzong

    2017-02-01

    In this work, an ASIC (application specific integrated circuits) transducer circuit for field modulated giant magnetoresistance (GMR) sensors was designed and fabricated using a 0.18-μ m CMOS process. The transducer circuits consist of a frequency divider, a digital phase shifter, an instrument amplifier, and an analog mixer. These comprise a mix of analog and digital circuit techniques. The compact chip size of 1.5 mm × 1.5 mm for both analog and digital parts was achieved using the TSMC18 1P6M (1-polysilicon 6-metal) process design kit, and the characteristics of the system were simulated using an HSpice simulator. The output of the transducer circuit is the result of the first harmonic detection, which resolves the modulated field using a phase sensitive detection (PSD) technique and is proportional to the measured magnetic field. When the dual-bridge GMR sensor is driven by the transducer circuit with a current of 10 mA at 10 kHz, the observed sensitivity of the field sensor is 10.2 mV/V/Oe and the nonlinearity error was 3% in the linear range of ±1 Oe. The performance of the system was also verified by rotating the sensor system horizontally in earth's magnetic field and recording the sinusoidal output with respect to the azimuth angle, which exhibits an error of less than ±0.04 Oe. These results prove that the ASIC transducer is suitable for driving the AC field modulated GMR sensors applied to geomagnetic measurement.

  13. Effects of increased compression with an ultrasound transducer on the conspicuity of breast lesions in a phantom

    Science.gov (United States)

    Szczepura, Katy; Faqir, Tahreem; Manning, David

    2017-03-01

    Ultrasound imaging of the breast is highly operator dependent. The amount of pressure applied with the transducer has a direct impact on the lesion visibility in breast ultrasound. The conspicuity index is a quantitative measure of lesion visibility, taking into account more parameters than standard measures that impact on lesion detection. This study assessed the conspicuity of lesions within a breast phantom using increased transducer compression in breast ultrasound. Methods A phantom was constructed of gelatine to represent adipose tissue, steel wool for glandular/blood vessels and silicone spheres to represent lesions, this meant that the lesions were also compressible, but less than the surrounding tissue. The phantom was imaged under increasing transducer compression. The conspicuity index was measured using the Conspicuity Index Software. The distance between the transducer surface and lesion surface was measured as an indication of increased compression. Results When moderate compression (17mm) was applied, the conspicuity index increased resulting in better visualisation of the silicone lesions. However, with increased compression the conspicuity index decreased. New work to be presented The conspicuity index has never been demonstrated in ultrasound imaging before. This is preliminary phantom work to demonstrate the impact of increased transducer compression on quantitative lesion visibility assessment. Conclusion The compression applied should be considered for optimum visualisation, as excessive pressure decreases conspicuity. However, further work needs to be conducted in order to consider other factors, such as density of the breast and lesion location, for a better understanding of the effect of compression on the visualisation of the lesion. A human study is planned.

  14. The measurement of tremor using a velocity transducer: comparison to simultaneous recordings using transducers of displacement, acceleration and muscle activity.

    Science.gov (United States)

    Norman, K E; Edwards, R; Beuter, A

    1999-10-15

    Precise kinematic measurements of tremor have historically been obtained using accelerometers. However, current technology permits precise measurements in velocity and displacement. The primary advantage of velocity recording is that only one step of integration or differentiation is required for either displacement or acceleration. A method is presented of measuring finger tremor using a laser system that transduces velocity precisely. Measurements of postural finger tremor thus obtained were compared to those simultaneously obtained from a laser system that transduces displacement, from an accelerometer and from surface electromyography (EMG) of the extensor digitorum communis. A range of amplitude and frequency content was obtained by testing control subjects and subjects with Parkinson's disease. The velocity transducer showed excellent correspondence of amplitude and frequency measurement with the displacement transducer. Measures of absolute and relative amplitude correlated well (r > or = 0.96 in amplitude measures in displacement, velocity and acceleration), and high coherence was found throughout the frequency range of interest. Measurements by the accelerometer generally showed poorer correspondence with those of the other instruments. EMG measurements showed good correspondence in some trials but poorer correspondence in others, attributed to the low level of muscle activity required in the task. Precise kinematic measurements appear to be highly sensitive to neuromotor impairment.

  15. Adenoviral Mediated LacZ Gene Expression in the Guinea Pig Cochlea%腺病毒携带的LacZ基因在豚鼠耳蜗中的表达

    Institute of Scientific and Technical Information of China (English)

    时利; 翟所强; 郭维; 胡吟燕

    2001-01-01

    目的 带有LacZ基因的腺病毒注入豚鼠耳蜗后,观察不同时间段LacZ基因的表达和分布情况及手术操作对听力的影响,为内耳基因治疗提供理论依据。方法 24只白色豚鼠术前及术后行听性脑干反应(ABR)检查。空白对照组经圆窗注入人工外淋巴液,实验组注入带有LacZ基因的腺病毒。分别于2天、1周、2周后取材。耳蜗标本经β-半乳糖苷酶(X-Gal)组织化学染色后做石蜡切片和耳蜗铺片。结果 腺病毒注入耳蜗后对听力影响不大。经X-Gal染色后整个耳蜗被染成蓝色。2天组表达产物最高,1周后逐渐降低。表达产物主要分布于柯蒂器的内外毛细胞、螺旋神经节细胞、基底膜下的间皮细胞。对照组均未着色。结论 通过圆窗注入腺病毒对听力没有影响,单一位点的接种就能使因子通过耳蜗液扩散到整个耳蜗。有效的基因转移在耳蜗是可行的,但表达相对短暂。%Objective To observe the expression and cellular distribution of LacZ gene in the cochlea, and to assess the effect of the operation on hearing. Methods Twenty-four albino guinea pigs were used in this study. The auditory function was assessed by measuring the auditory brainstem response(ABR). The experimental and the control guinea pigs were inoculated with adenovirus carrying the report gene LacZ. And the control group were inoculated with artifieal perilymphatic fluid. After 2 days, 7 days and 14 days, the animals were sacrificed and the cochleas were stained with X-Gal. Results ABR showed that the operation had no significant effect on the ABR thresholds. Gene expressed in the spiral ganglion, the inner and outer hair cells and mesothelial cells in the basilar membrane. Gene expression was in high level two days after the adenovirus administration and reduced thereafter. Control animals were not stained by X-Gal.Conclusion Gene inoculated through the round window can spread the

  16. Six-Axis Force-Torque Transducer for Mars 2018 Mission Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A transducer element that is hearty enough for a Mars lander mission needs to be developed so that a six-axis force and torque transducer is possible. The technical...

  17. PMN-PT single crystal focusing transducer fabricated using a mechanical dimpling technique.

    Science.gov (United States)

    Lam, K H; Chen, Y; Cheung, K F; Dai, J Y

    2012-01-01

    A ∼5MHz focusing PMN-PT single crystal ultrasound transducer has been fabricated utilizing a mechanical dimpling technique, where the dimpled crystal wafer was used as an active element of the focusing transducer. For the dimpled focusing transducer, the effective electromechanical coupling coefficient was enhanced significantly from 0.42 to 0.56. The dimpled transducer also yields a -6dB bandwidth of 63.5% which is almost double the bandwidth of the plane transducer. An insertion loss of the dimpled transducer (-18.1dB) is much lower than that of the plane transducer. Finite element simulation also reveals specific focused beam from concave crystal surface. These promising results show that the dimpling technique can be used to develop high-resolution focusing single crystal transducers.

  18. Directional properties of an 18-KHZ transducer: Proprietes directionnelles d'un transducteur 18 KHZ

    National Research Council Canada - National Science Library

    Foote, K.G

    1993-01-01

    Several theoretical measures of directivity are given for an 18-kHz transducer that is used in both single-beam and split- beam applications, namely the SIMRAD transducer type 18-11 in the single-beam variant...

  19. Hazardous effects of effluent from the chrome plating industry: 70 kDa heat shock protein expression as a marker of cellular damage in transgenic Drosophila melanogaster (hsp70-lacZ).

    Science.gov (United States)

    Mukhopadhyay, Indranil; Saxena, Daya Krishna; Chowdhuri, Debapratim Kar

    2003-01-01

    Hazardous effects of an effluent from the chrome plating industry were examined by exposing transgenic Drosophila melanogaster (hsp70-lacZ) to various concentrations (0.05, 0.1, 1.0, 10.0, and 100.0 micro L/mL) of the effluent through diet. The emergence pattern of adult flies was affected, along with impaired reproductive performance at the higher dietary concentrations of the effluent. Interestingly, the effect of the effluent was more pronounced in male than in female flies. The effect of the effluent on development of adult flies was concurrent with the expression pattern of the heat shock protein 70 gene (hsp70), both in larval tissues and in the reproductive organs of adult flies. We observed a dose- and time-dependent expression of hsp70 in third instar larvae exposed for different time intervals. Absence of hsp70 expression in larvae exposed to 0.1 micro L/mL of the effluent indicated that this is the highest nontoxic concentration for Drosophila. The stress gene assay in the reproductive organs of adult flies revealed hsp70 expression in the testis of male flies only. However, trypan blue dye exclusion tests in these tissues indicate tissue damage in the male accessory gland of adult flies, which was further confirmed by ultrastructural observations. In the present study we demonstrate the utility of transgenic Drosophila as an alternative animal model for evaluating hazardous effects of the effluent from the chrome plating industry and further reveal the cytoprotective role of hsp70 and its expression as an early marker in environmental risk assessment. PMID:14644668

  20. Switchable adhesion for wafer-handling based on dielectric elastomer stack transducers

    Science.gov (United States)

    Grotepaß, T.; Butz, J.; Förster-Zügel, F.; Schlaak, H. F.

    2016-04-01

    Vacuum grippers are often used for the handling of wafers and small devices. In order to evacuate the gripper, a gas flow is created that can harm the micro structures on the wafer. A promising alternative to vacuum grippers could be adhesive grippers with switchable adhesion. There have been some publications of gecko-inspired adhesive devices. Most of these former works consist of a structured surface which adheres to the object manipulated and an actuator for switching the adhesion. Until now different actuator principles have been investigated, like smart memory alloys and pneumatics. In this work for the first time dielectric elastomer stack transducers (DEST) are combined with a structured surface. DESTs are a promising new transducer technology with many applications in different industry sectors like medical devices, human-machine-interaction and soft robotics. Stacked dielectric elastomer transducers show thickness contraction originating from the electromechanical pressure of two compliant electrodes compressing an elastomeric dielectric when a voltage is applied. Since DESTs and the adhesive surfaces previously described are made of elastomers, it is self-evident to combine both systems in one device. The DESTs are fabricated by a spin coating process. If the flat surface of the spinning carrier is substituted for example by a perforated one, the structured elastomer surface and the DEST can be fabricated in one process. By electrical actuation the DEST contracts and laterally expands which causes the gecko-like cilia to adhere on the object to manipulate. This work describes the assembly and the experimental results of such a device using switchable adhesion. It is intended to be used for the handling of glass wafers.

  1. One-dimensional analysis of piezoelectric transducers based on Thevenin theorem

    OpenAIRE

    Arnold, FJ

    2009-01-01

    In this work, a method of analysis of piezoelectric transducers is shown. This method is based on the simplification of Mason's equivalent electric circuit. An adaptation of Thevenin theorem has been employed to study the behavior of piezoelectric transducers used as transmitters (electric into mechanic energy conversion). This study was restricted to transducers with a typical configuration employed in high power applications. The transducers were one-dimensionally modeled, considering only ...

  2. Modeling the radiation of ultrasonic phased-array transducers with Gaussian beams.

    Science.gov (United States)

    Huang, Ruiju; Schmerr, Lester W; Sedov, Alexander

    2008-12-01

    A new transducer beam model, called a multi-Gaussian array beam model, is developed to simulate the wave fields radiated by ultrasonic phased-array transducers. This new model overcomes the restrictions on using ordinary multi-Gaussian beam models developed for large single-element transducers in phased-array applications. It is demonstrated that this new beam model can effectively model the steered and focused beams of a linear phased-array transducer.

  3. Eddy Current Transducer Dedicated for Sigma Phase Evaluation in Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Grzegorz Psuj

    2012-01-01

    Full Text Available The paper describes a new transducer dedicated for evaluation of a duplex stainless steel (DSS. Different phases which exist in DSS have influence on mechanical as well as on electrical properties. Therefore, an eddy current transducer was utilized. In order to achieve high sensitivity, a differential type of the transducer was selected. The performance of the transducer was verified by utilizing the samples which had a different amount of sigma phase.

  4. Gene expression studies on human keratinocytes transduced with human growth hormone gene for a possible utilization in gene therapy; Estudos da expressao genica mediante utilizacao de queratinocitos humanos normais transduzidos com o gene do hormonio de crscimento humano. Possivel utilizacao em terapia genica

    Energy Technology Data Exchange (ETDEWEB)

    Mathor, Monica Beatriz

    1994-12-31

    Taking advantage of the recent progress in the DNA-recombinant techniques and of the potentiality of normal human keratinocytes primary culture to reconstitute the epidermis, it was decided to genetically transform these keratinocytes to produce human growth hormone under controllable conditions that would be used in gene therapy at this hormone deficient patients. The first step to achieve this goal was to standardize infection of keratinocytes with retrovirus producer cells containing a construct which included the gene of bacterial b-galactosidase. The best result was obtained cultivating the keratinocytes for 3 days in a 2:1 mixture of retrovirus producer cells and 3T3-J2 fibroblasts irradiated with 60 Gy, and splitting these infected keratinocytes on 3T3-J2 fibroblasts feeder layer. Another preliminary experiment was to infect normal human keratinocytes with interleukin-6 gene (hIL-6) that, in pathologic conditions, could be reproduced by keratinocytes and secreted to the blood stream. Thus, we verify that infected keratinocytes secrete an average amount of 500 ng/10{sup 6} cell/day of cytokin during the in vitro life time, that certify the stable character of the injection. These keratinocytes, when grafted in mice, secrete hIL-6 to the blood stream reaching levels of 40 pg/ml of serum. After these preliminary experiments, we construct a retroviral vector with the human growth hormone gene (h GH) driven by human metallothionein promoter (h PMT), designated DChPMTGH. Normal human keratinocytes were infected with DChPMTGH producer cells, following previously standardized protocol, obtaining infected keratinocytes secreting to the culture media 340 ng h GH/10{sup 6} cell/day without promoter activation. This is the highest level of h GH secreted in human keratinocytes primary culture described in literature. The h GH value increases approximately 10 times after activation with 100 {mu}M Zn{sup +2} for 8-12 hours. (author). 158 refs., 42 figs., 6 tabs.

  5. Piezoelectric micromachined ultrasonic transducers for fingerprint sensing

    Science.gov (United States)

    Lu, Yipeng

    Fingerprint identification is the most prevalent biometric technology due to its uniqueness, universality and convenience. Over the past two decades, a variety of physical mechanisms have been exploited to capture an electronic image of a human fingerprint. Among these, capacitive fingerprint sensors are the ones most widely used in consumer electronics because they are fabricated using conventional complementary metal oxide semiconductor (CMOS) integrated circuit technology. However, capacitive fingerprint sensors are extremely sensitive to finger contamination and moisture. This thesis will introduce an ultrasonic fingerprint sensor using a PMUT array, which offers a potential solution to this problem. In addition, it has the potential to increase security, as it allows images to be collected at various depths beneath the epidermis, providing images of the sub-surface dermis layer and blood vessels. Firstly, PMUT sensitivity is maximized by optimizing the layer stack and electrode design, and the coupling coefficient is doubled via series transduction. Moreover, a broadband PMUT with 97% fractional bandwidth is achieved by utilizing a thinner structure excited at two adjacent mechanical vibration modes with overlapping bandwidth. In addition, we proposed waveguide PMUTs, which function to direct acoustic waves, confine acoustic energy, and provide mechanical protection for the PMUT array. Furthermore, PMUT arrays were fabricated with different processes to form the membrane, including front-side etching with a patterned sacrificial layer, front-side etching with additional anchor, cavity SOI wafers and eutectic bonding. Additionally, eutectic bonding allows the PMUT to be integrated with CMOS circuits. PMUTs were characterized in the mechanical, electrical and acoustic domains. Using transmit beamforming, a narrow acoustic beam was achieved, and high-resolution (sub-100 microm) and short-range (~1 mm) pulse-echo ultrasonic imaging was demonstrated using a steel

  6. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Science.gov (United States)

    Reinhardt, Brian; Tittmann, Bernhard; Rempe, Joy; Daw, Joshua; Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov; Ramuhalli, Pradeep; Montgomery, Robert; Chien, Hualte; Wernsman, Bernard

    2015-03-01

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

  7. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Brian; Tittmann, Bernhard [The Pennsylvania State University (United States); Rempe, Joy; Daw, Joshua [Idaho National Laboratory (United States); Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov [Massachusetts Institute of Technology (United States); Ramuhalli, Pradeep; Montgomery, Robert [Pacific Northwest National Laboratory (United States); Chien, Hualte [Argonne National Laboratory (United States); Wernsman, Bernard [Bechtel Marine Propulsion Corp (United States)

    2015-03-31

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

  8. Forced and free displacement characterization of ionic polymer transducers

    Science.gov (United States)

    Akle, Barbar J.; Duncan, Andrew; Akle, Etienne; Wallmersperger, Thomas; Leo, Donald J.

    2009-03-01

    Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages (transducers. In this study, extensional IPTs are characterized under forced and free displacement boundary condition as a function of transducer architecture. The electrode thickness is varied from 10 μm up to 40 μm while three extensional actuators with Lithium, Cesium, and tetraethylammonium (TEA) mobile cations are characterized. Three fixtures are built in order to characterize the extensional actuation response. The first fixture measures the free displacement of an IPT sample sandwiched between two aluminum plates glued using the electrically conductive silver paste. In the second fixture a spring is compressed against the test sample with variable amounts to generate different levels of pre-stress and prevents the bending of the IPT. In the third fixture dead weights are placed on top of the sample in order to prevent bending. In the spring loaded fixture a thermocouple is placed in the proximity of the actuator and temperature is measured. The different transducers are characterized using a step voltage input and an alternating current (AC) sine wave input. The step input resulted in a logarithmic rise like displacement curve, while the low frequency (wave displacement response with a strong first harmonic. The high frequency AC excitation generated a response similar to that of the step input. Comparing the measured temperature for step and AC response demonstrated that the sample is heating up when exited with a high frequency signal; which is leading to the expansion of the sample. Initial experimental results demonstrate a strong correlation between electrode architecture and the peak strain response. Strains on the order of 2% are observed with air stable ionic liquid based transducers. A correlation between the strain and charge buildup in the polymer is also characterized. Cesium

  9. 21 CFR 870.2900 - Patient transducer and electrode cable (including connector).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Patient transducer and electrode cable (including... § 870.2900 Patient transducer and electrode cable (including connector). (a) Identification. A patient transducer and electrode cable (including connector) is an electrical conductor used to transmit signals from...

  10. Experimental analysis of 1-3 piezocomposites for high-intensity focused ultrasound transducer applications.

    Science.gov (United States)

    Chen, Gin-Shin; Liu, Hsin-Chih; Lin, Yu-Cheng; Lin, Yu-Li

    2013-01-01

    Piezocomposites with 1-3 connectivity have been extensively used in medical imaging transducers and high-intensity focused ultrasound transducers, but most studies of 1-3 piezocomposites address medical imaging applications. The purpose of this study was to completely investigate 1-3 composites specifically for high-power ultrasonic transducer applications via a series of experimental analyses. PZT4-epoxy composite focused transducers with various aspect ratios and volume fractions were constructed in-house for the evaluation of the coupling factor, dielectric loss tangent, quality factor, bandwidth, acoustic impedance, and electroacoustic efficiency. The experimental analyses demonstrated that although the coupling factor of composite transducers was higher than that of the ceramic transducer, the composite transducers had a lower efficiency due to the high dielectric loss and high mechanical energy loss of the composites. In addition, the bandwidth and acoustic impedance of composite transducers were superior to the ceramic transducer. For the composite transducers, the efficiency and acoustic impedance were inversely proportional to the aspect ratio and linearly proportional to the volume fraction. The coupling of inter pillars that are too close to each other could cause a significant decrease in the efficiency of the composite transducer. With an appropriate design in terms of the aspect ratio, volume fraction, and PZT-pillar spacing, a high-efficiency composite high-intensity focused ultrasound transducer can be achieved.

  11. Modeling of nonlinear responses for reciprocal transducers involving polarization switching

    DEFF Research Database (Denmark)

    Willatzen, Morten; Wang, Linxiang

    2007-01-01

    Nonlinearities and hysteresis effects in a reciprocal PZT transducer are examined by use of a dynamical mathematical model on the basis of phase-transition theory. In particular, we consider the perovskite piezoelectric ceramic in which the polarization process in the material can be modeled....... We present numerical results for the reciprocal-transducer system and identify the influence of nonlinearities on the system dynamics at high and low frequency as well as electrical impedance effects due to tuning by a series inductance. It is found that nonlinear effects are not important at high...... by Landau theory for the first-order phase transformation, in which each polarization state is associated with a minimum of the Landau free-energy function. Nonlinear constitutive laws are obtained by using thermodynamical equilibrium conditions, and hysteretic behavior of the material can be modeled...

  12. Broadband electrostatic acoustic transducer for ultrasonic measurements in liquids.

    Science.gov (United States)

    Cantrell, J H; Heyman, J S; Yost, W T; Torbett, M A; Breazeale, M A

    1979-01-01

    A broadband capacitive electrostatic acoustic transducer (ESAT) has been developed for use in a liquid environment at megahertz frequencies. The ESAT basically consists of a thin conductive membrane stretched over a metallic housing. The membrane functions as the ground plate of a parallel plate capacitor, the other plate being a dc biased electrode recessed approximately 10 mum from the electrically grounded membrane. An ultrasonic wave incident on the membrane varies the membrane-electrode gap spacing and generates an electrical signal proportional to the wave amplitude. The entire assembly is sealed for immersion in a liquid environment. Calibration of the ESAT with incident ultrasonic waves of constant displacement amplitude from 1 to 15 MHz reveals a decrease in signal response with increasing frequency independent of membrane tension. The use of the ESAT as a broadband ultrasonic transducer in liquids with a predictable frequency response is promising.

  13. Force transducers based on the stress dependence of coercive force

    Science.gov (United States)

    Garshelis, I. J.

    1993-05-01

    An alternative measurement regime for magnetoelastic force transducers, based on variations in coercive field, is described. Hc is shown to be more directly related to the primary magnetic influence of stress, namely, the orientation of effective anisotropy, than conventionally used magnetization related parameters. The stress dependence of Hc is shown to generally reflect opposing factors associated with rotational and wall displacement magnetization reversal processes. In materials wherein Hc≪K/Ms wall motion dominates and if the product of λs/K and yield stress is high enough, large monotonic reductions of Hc with positive (tensile) stress are shown to be possible. A more complex variation of Hc with increasing compression is similarly expected. Experimental results from a transducer having an 18% Ni maraging steel core support these expectations.

  14. CMOS biosensors for in vitro diagnosis - transducing mechanisms and applications.

    Science.gov (United States)

    Lei, Ka-Meng; Mak, Pui-In; Law, Man-Kay; Martins, Rui P

    2016-09-21

    Complementary metal oxide semiconductor (CMOS) technology enables low-cost and large-scale integration of transistors and physical sensing materials on tiny chips (e.g., key functions of biosensors: transducing and signal processing. Recent CMOS biosensors unified different transducing mechanisms (impedance, fluorescence, and nuclear spin) and readout electronics have demonstrated competitive sensitivity for in vitro diagnosis, such as detection of DNA (down to 10 aM), protein (down to 10 fM), or bacteria/cells (single cell). Herein, we detail the recent advances in CMOS biosensors, centering on their key principles, requisites, and applications. Together, these may contribute to the advancement of our healthcare system, which should be decentralized by broadly utilizing point-of-care diagnostic tools.

  15. An Energy-Based Hysteresis Model for Magnetostrictive Transducers

    Science.gov (United States)

    Calkins, F. T.; Smith, R. C.; Flatau, A. B.

    1997-01-01

    This paper addresses the modeling of hysteresis in magnetostrictive transducers. This is considered in the context of control applications which require an accurate characterization of the relation between input currents and strains output by the transducer. This relation typically exhibits significant nonlinearities and hysteresis due to inherent properties of magnetostrictive materials. The characterization considered here is based upon the Jiles-Atherton mean field model for ferromagnetic hysteresis in combination with a quadratic moment rotation model for magnetostriction. As demonstrated through comparison with experimental data, the magnetization model very adequately quantifies both major and minor loops under various operating conditions. The combined model can then be used to accurately characterize output strains at moderate drive levels. The advantages to this model lie in the small number (six) of required parameters and the flexibility it exhibits in a variety of operating conditions.

  16. Electromechanical modelling of tapered ionic polymer metal composites transducers

    Directory of Open Access Journals (Sweden)

    Rakesha Chandra Dash

    2016-09-01

    Full Text Available Ionic polymer metal composites (IPMCs are relatively new smart materials that exhibit a bidirectional electromechanical coupling. IPMCs have large number of important engineering applications such as micro robotics, biomedical devices, biomimetic robotics etc. This paper presents a comparison between tapered and uniform cantilevered Nafion based IPMCs transducer. Electromechanical modelling is done for the tapered beam. Thickness can be varied according to the requirement of force and deflection. Numerical results pertaining to the force and deflection characteristics of both type IPMCs transducer are obtained. It is shown that the desired amount of force and deflections for tapered IPMCs can be achieved for a given voltage. Different fixed end (t0 and free end (t1 thickness values have been taken to justify the results using MATLAB.

  17. A novel design of micromachined capacitive Lamb wave transducers

    Science.gov (United States)

    Ge, Lifeng

    2006-11-01

    A new design for micromachined capacitive Lamb wave transducers (mCLWT) has been developed. The design is based on a theoretical TDK model previously developed for groove ultrasonic transducers. By the investigation of the dynamic behavior of a rectangular high aspect ratio diaphragm of the mCLWTs, the second order bending mode of the diaphragm is exploited to excite and detect Lamb wave. The new exiting mechanism can minimize the energy of the acoustic radiation at the normal direction of the diaphragm so as to provide more energy coupled into the Lamb wave in the silicon substrate. Also, the natural frequencies and mode shapes of such a mCLWT can be determined accurately from its geometry and materials used, so the TDK model provides guidance for the optimal design of mCLWTs.

  18. New Soft Polymeric Materials Applicable as Elastomeric Transducers

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Skov, Anne Ladegaard

    between two compliant electrodes will reduce its thickness and expand its area. The electrical energy transformed into mechanical energy is called actuation and it is studied in the technology of elastomeric transducers. While DEs deform under high voltage, the actuation varies for different materials......). In the present study hyperswollen silicone networks are synthesized and rheologically characterized. Their viscoelastic properties make them good candidates for elastomeric transducers. Silicone networks are synthesized using a hydrosilylation reaction at room temperature between vinyl-terminated polydimethyl......An elastomer is a material characterized by the capability to regain its original size and shape after being deformed (stretched or distorted). An ideal elastomer for electroactive polymer (EAP) applications is a system characterized by high extensibility, flexibility and a good mechanical fatigue...

  19. The copying power of one-state tree transducers

    DEFF Research Database (Denmark)

    Engelfriet, Joost; Skyum, Sven

    1982-01-01

    One-state deterministic top-down tree transducers (or, tree homomorphisms) cannot handle “prime copying,” i.e., their class of output (string) languages is not closed under the operation L → {$(w$)f(n) short parallel w ε L, f(n) greater-or-equal, slanted 1}, where f is any integer function whose...... range contains numbers with arbitrarily large prime factors (such as a polynomial). The exact amount of nonclosure under these copying operations is established for several classes of input (tree) languages. These results are relevant to the extended definable (or, restricted parallel level) languages......, to the syntax-directed translation of context-free languages, and to the tree transducer hierarchy....

  20. FOULING DETECTION IN FOOD VESSELS USING INTERDIGITAL LAMB WAVE TRANSDUCER

    Institute of Scientific and Technical Information of China (English)

    JIAO Jingpin; GE Haiyan; WU Bin; HE Cunfu

    2007-01-01

    Lamb waves are used to detect fouling in food vessels. The propagation of the Lamb waves in plates exhibits many modes and dispersion characteristics, which have great influence on fouling detection. The relative distribution of the in-plane and out-of-plane displacement of the mode across the thickness of the plate will determine the sensitivity of the mode to a particular loading condition. By considering the dispersion and multi-mode characteristics of guided waves, an interdigital polyvinylidene fluoride (PVDF) transducer is designed to realize the mode selection of guided waves, and a single α0 mode is used for guided wave detection. Fouling detection experiments are conducted in the laboratory using epoxy adhesive on a thin plate. Using the interdigital PVDF transducer, three fouled areas are detected. Using one of the time-frequency analysis methods, the waveforms are further processed. This also demonstrates the validity of this method of fouling detection.

  1. Finite element analysis of hysteresis effects in piezoelectric transducers

    Science.gov (United States)

    Simkovics, Reinhard; Landes, Hermann; Kaltenbacher, Manfred; Hoffelner, Johann; Lerch, Reinhard

    2000-06-01

    The design of ultrasonic transducers for high power applications, e.g. in medical therapy or production engineering, asks for effective computer aided design tools to analyze the occurring nonlinear effects. In this paper the finite-element-boundary-element package CAPA is presented that allows to model different types of electromechanical sensors and actuators. These transducers are based on various physical coupling effects, such as piezoelectricity or magneto- mechanical interactions. Their computer modeling requires the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields as well as coupled mechanical-acoustic fields. With the reported software environment we are able to compute the dynamic behavior of electromechanical sensors and actuators by taking into account geometric nonlinearities, nonlinear wave propagation and ferroelectric as well as magnetic material nonlinearities. After a short introduction to the basic theory of the numerical calculation schemes, two practical examples will demonstrate the applicability of the numerical simulation tool. As a first example an ultrasonic thickness mode transducer consisting of a piezoceramic material used for high power ultrasound production is examined. Due to ferroelectric hysteresis, higher order harmonics can be detected in the actuators input current. Also in case of electrical and mechanical prestressing a resonance frequency shift occurs, caused by ferroelectric hysteresis and nonlinear dependencies of the material coefficients on electric field and mechanical stresses. As a second example, a power ultrasound transducer used in HIFU-therapy (high intensity focused ultrasound) is presented. Due to the compressibility and losses in the propagating fluid a nonlinear shock wave generation can be observed. For both examples a good agreement between numerical simulation and experimental data has been achieved.

  2. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Brian [Pennsylvania State Univ., University Park, PA (United States). Dept. of Engineering Science and Mechanics; Tittmann, Bernhard [Pennsylvania State Univ., University Park, PA (United States). Dept. of Engineering Science and Mechanics; Rempe, Joy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Daw, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kohse, Gordon [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Carpenter, David [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Ames, Micheal [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Ostrovsky, Yakov [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chien, Hualte [Argonne National Lab. (ANL), Argonne, IL (United States); Wernsman, Bernard [Bettis Atomic Power Lab. (BAPL), West Mifflin, PA (United States). Bechtel Marine Propulsion Corp.

    2014-07-01

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) provide harsh environments in and near the core that can severely test material performance and limit their operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration radiation performance of fuels and materials. In To reduce the amount of Material and Test Reactor (MTR) irradiations required, DOE is also funding development of enhanced instrumentation that will be able to obtain data, with unprecedented accuracy and resolution, that are required to validate new multi-scale multiphysics modeling tools . It is not feasible to obtain such data with the current state of instrumentation technology. To address this need, PSU and collaborators have started an experiment to test the potential for utilizing ultrasonic instruments in-pile. Ultrasonic sensors must be resistant to high neutron flux, high gamma radiation, and high temperature. PSU and collaborators have designed, fabricated, and started to irradiate piezoelectric and magnetostrictive transducers designed to perform in such harsh environments. Three piezoelectric transducers were fabricated with aluminum nitride, zinc oxide, and bismuth titanate as the active element. The transducers are coupled kovar and aluminum waveguides of which pulse-echo ultrasonic measurements are made in-situ. Two magnetostrictive transducers were fabricated with Remendur and Arnokrome as the active elements. These devices will be pulsed and monitored in-situ. (1) Selection of candidate sensor materials as well as optimization of test assembly parameters (2) High temperature benchmark testing and (3) initial data from the irradiation will be reported.

  3. Analytical and Experimental Issues in Ni-Mn-Ga Transducers

    Science.gov (United States)

    2003-01-01

    tests seen in Figure 10 can cause test repeatability problems due to heat issues in the sample, transducer, and amplifiers. However, with adequate...layered martensitic phase,” Appl. Phys. Let. 80, pp. 1746–1749, March 2002. 5. V. Pecharsky and J. K.A. Gshneidner, “Giant magnetocaloric effect in...giant magnetocaloric effect for magnetic refrigeration from 20 to 290 k,” Applied Physics Letters 70, pp. 3299–3301, June 1997. 7. A. Malla, M

  4. Detecting Casimir Forces through a Tunneling Electromechanical Transducer

    OpenAIRE

    Onofrio, Roberto; Carugno, Giovanni

    1995-01-01

    We propose the use of a tunneling electromechanical transducer to dynamically detect Casimir forces between two conducting surfaces. The maximum distance for which Casimir forces should be detectable with our method is around $1 \\mu$m, while the lower limit is given by the ability to approach the surfaces. This technique should permit to study gravitational forces on the same range of distances, as well as the vacuum friction provided that very low dissipation mechanical resonators are used.

  5. An evaluation of conflation accuracy using finite-state transducers

    OpenAIRE

    Galvez, Carmen; De-Moya-Anegón, Félix

    2006-01-01

    Purpose – To evaluate the accuracy of conflation methods based on Finite-State Transducers (FSTs). Design/methodology/approach – Incorrectly lemmatized and stemmed forms may lead to the retrieval of inappropriate documents. Experimental studies to date have focused on retrieval performance, but very few on conflation performance. The process of normalization we used involved a linguistic toolbox that allowed us to construct, through graphic interfaces, electronic dictionaries represented i...

  6. Engine Oil Condition Monitoring Using High Temperature Integrated Ultrasonic Transducers

    OpenAIRE

    Jeff Bird; Cheng-Kuei Jen; Zhigang Sun; Pierre Sammut; Brian Galeote; Makiko Kobayashi; Kuo-Ting Wu; Nezih Mrad

    2011-01-01

    The present work contains two parts. In the first part, high temperature integrated ultrasonic transducers (IUTs) made of thick piezoelectric composite films, were coated directly onto lubricant oil supply and sump lines of a modified CF700 turbojet engine. These piezoelectric films were fabricated using a sol-gel spray technology. By operating these IUTs in transmission mode, the amplitude and velocity of transmitted ultrasonic waves across the flow channel of the lubricant oil in supply and...

  7. Tonpilz Underwater Acoustic Transducer Integrating Lead-free Piezoelectric Material

    Science.gov (United States)

    Rouffaud, Rémi; Granger, Christian; Hladky-Hennion, Anne-Christine; Thi, Mai Pham; Levassort, Franck

    A Tonpilz transducer based on lead-free piezoelectric material was fabricated, modeled and characterized. The stack is composed of two rings of doped BaTiO3. This composition was initially chosen due to good electromechanical performance (kt at 40%) and high mechanical quality factor (Qm over 500). Comparison of the displacement at the center of the head mass was performed with a PZT-based Tonpilz with the same design for a center frequency at 22 kHz.

  8. Sensitivity limits of capacitive transducer for gravitational wave resonant antennas

    Energy Technology Data Exchange (ETDEWEB)

    Bassan, M.; Pizzella, G. [Rome Tor Vergata Univ. (Italy). Dip. di Fisica

    1996-12-01

    It is analyzed the performance of a resonant gravitational wave antenna equipped with a resonant, d.c. biased capacitive transducer, an untuned superconducting matching circuit and a d.c. Squid. It is derived simple relations for the detector energy sensitivity that serve as guidelines for device development and it is shown that, with reasonable improvements in Squid technology, an effective temperature for burst detection of 2miK can be achieved.

  9. Short notes on electromagnetic acoustic transducers (EMATs design and modeling

    Directory of Open Access Journals (Sweden)

    Hocine Menana

    2017-03-01

    Full Text Available This paper gives short notes on the electromagnetic acoustic transducers (EMATs design and modeling. The principle of the electromagnetic-acoustic transduction as well as the various EMATs structures are described, highlighting the important characteristics of each structure. Analytical models are given in global quantities in order to quantify the electromagnetic-acoustic transduction efficiency. The numerical modeling of such structures is also addressed.

  10. Acoustic Radiation from Transducer in Semi-infinite Fluid Medium

    Science.gov (United States)

    2016-06-07

    IIIII v 841087 121CilN ACOUSTIC RADIATION F~ TRANSDUCER IN SFMI-INFINITE FLUID MEDIUM Date: June 19, 1984 Prepared by: Jay ant S. Patel...1. REPORT DATE 19 JUN 1984 2. REPORT TYPE Technical Memo 3. DATES COVERED 19-06-1984 to 19-06-1984 4. TITLE AND SUBTITLE Acoustic Radiation ...Technical Menorandum TM No. 841087 ACOUSTIC RADIATION FROM TRANSOOCER IN SEMI-INFINITE FliJID MEDIUM Date: June 19, 1984 Prepared by: Jayant s. Patel

  11. Radio-frequency plasma transducer for use in harsh environments.

    Science.gov (United States)

    May, Andrew; Andarawis, Emad

    2007-10-01

    We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer, eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0-5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

  12. Stable 600 °C silicon carbide MEMS pressure transducers

    Science.gov (United States)

    Okojie, Robert S.

    2007-04-01

    This paper presents a review of recent results of silicon carbide (SiC) piezoresistive pressure transducers that have been demonstrated to operate up to 600 °C. The results offer promise to extend pressure measurement to higher temperatures beyond the capability of conventional semiconductor pressure transducers. The development also provides three immediate significant technological benefits: i) wider frequency bandwidth (overcomes acoustic attenuation associated with pitot tubes), ii) accuracy (improved stable output at high temperature), and iii) reduced packaging complexity (no package cooling required). Operation at 600 °C provides immediate applications in military and commercial jet engines in which critical static and dynamic pressure measurements are performed to improve engine performance (i.e., reduced emission and combustor instabilities) and improved CFD code validation. The pressure sensor is packaged by a novel MEMS direct chip attach (MEMS-DCA) technique that eliminates the need for wire bonding, thereby removing some reliability issues encountered at high temperature. Generally, at 600 °C the full-scale output (FSO) of these transducers drops by about 50-65 % of the room temperature values, which can be compensated for with external signal conditioning circuitry.

  13. Thermal safety of vibro-acoustography using a confocal transducer.

    Science.gov (United States)

    Chen, Shigao; Aquino, Wilkins; Alizad, Azra; Urban, Matthew W; Kinnick, Randall; Greenleaf, James F; Fatemi, Mostafa

    2010-02-01

    Vibro-acoustography (VA) is an imaging method that forms a two-dimensional (2-D) image by moving two cofocused ultrasound beams with slightly different frequencies over the object in a C-scan format and recording acoustic emission from the focal region at the difference frequency. This article studies tissue heating due to a VA scan using a concentric confocal transducer. The three-dimensional (3-D) ultrasound intensity field calculated by Field II is used with the bio-heat equation to estimate tissue heating due to ultrasound absorption. Results calculated with thermal conduction and with blood perfusion, with conduction and without perfusion and without conduction and without perfusion are compared. Maximum heating due to ultrasound absorption occurs in the transducer's near-field and maximum temperature rise in soft tissue during a single VA scan is below 0.05 degrees C for all three attenuation coefficients evaluated: 0.3, 0.5 and 0.7 dB/cm/MHz. Transducer self-heating during a single VA scan measured by a thermocouple is less than 0.27 degrees C. 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  14. Performance analysis of ultrasono-therapy transducer with contact detection.

    Science.gov (United States)

    Moreno, Eduardo; González, Gilberto; Leija, Lorenzo; Rodríguez, Orlando; Castillo, Martha; Fuentes, Martín

    2003-06-01

    The performance of ultrasono-therapy transducer with contact detection by using the impedance phase change is described. Usually a therapy transducer is designed with a lambda/2 frontal plate glued to a PZT-4 piezoceramic. This plate ensures a good mechanical protection of the piezoceramic with a corresponding high-transmission energy. Normally this transducer is operated at the minimum at the frequency of the impedance module of its input electric impedance, but this operation point is affected by the shift caused by the expected temperature increase. This shift could be higher than the narrow bandwidth presented. As a result we obtain a decrease in the power level for medical treatment. Usually it is designed electronic drivers with automatic control that follow the frequency change, but the relatively narrow bandwidth introduces difficulty in the design. Another frequency operation point is presented here and analyzed using the criteria of the maximum of the impedance phase with a wider bandwidth than in the previous case. Simulation with mechanical losses are presented with experimental results that show the convenience of this criteria for practical application.

  15. Dual-Frequency Piezoelectric Transducers for Contrast Enhanced Ultrasound Imaging

    Directory of Open Access Journals (Sweden)

    K. Heath Martin

    2014-11-01

    Full Text Available For many years, ultrasound has provided clinicians with an affordable and effective imaging tool for applications ranging from cardiology to obstetrics. Development of microbubble contrast agents over the past several decades has enabled ultrasound to distinguish between blood flow and surrounding tissue. Current clinical practices using microbubble contrast agents rely heavily on user training to evaluate degree of localized perfusion. Advances in separating the signals produced from contrast agents versus surrounding tissue backscatter provide unique opportunities for specialized sensors designed to image microbubbles with higher signal to noise and resolution than previously possible. In this review article, we describe the background principles and recent developments of ultrasound transducer technology for receiving signals produced by contrast agents while rejecting signals arising from soft tissue. This approach relies on transmitting at a low-frequency and receiving microbubble harmonic signals at frequencies many times higher than the transmitted frequency. Design and fabrication of dual-frequency transducers and the extension of recent developments in transducer technology for dual-frequency harmonic imaging are discussed.

  16. Focused intravascular ultrasonic probe using dimpled transducer elements.

    Science.gov (United States)

    Chen, Y; Qiu, W B; Lam, K H; Liu, B Q; Jiang, X P; Zheng, H R; Luo, H S; Chan, H L W; Dai, J Y

    2015-02-01

    High-frequency focused intravascular ultrasonic probes were fabricated in this study using dimple technique based on PMN-PT single crystal and lead-free KNN-KBT-Mn ceramic. The center frequency, bandwidth, and insertion loss of the PMN-PT transducer were 34 MHz, 75%, and 22.9 dB, respectively. For the lead-free probe, the center frequency, bandwidth, and insertion loss were found to be 40 MHz, 72%, and 28.8 dB, respectively. The ultrasonic images of wire phantom and vessels with good resolution were obtained to evaluate the transducer performance. The -6 dB axial and lateral resolutions of the PMN-PT probe were determined to be 58 μm and 131 μm, respectively. For the lead-free probe, the axial and lateral resolutions were found to be 44 μm and 125 μm, respectively. These results suggest that the mechanical dimpling technique has good potential in preparing focused transducers for intravascular ultrasound applications.

  17. Deconvolution based photoacoustic reconstruction for directional transducer with sparsity regularization

    Science.gov (United States)

    Moradi, Hamid; Tang, Shuo; Salcudean, Septimiu E.

    2016-03-01

    We define a deconvolution based photoacoustic reconstruction with sparsity regularization (DPARS) algorithm for image restoration from projections. The proposed method is capable of visualizing tissue in the presence of constraints such as the specific directivity of sensors and limited-view Photoacoustic Tomography (PAT). The directivity effect means that our algorithm treats the optically-generated ultrasonic waves based on which direction they arrive at the transducer. Most PA image reconstruction methods assume that sensors have omni-directional response; however, in practice, the sensors show higher sensitivity to the ultrasonic waves coming from one specific direction. In DPARS, the sensitivity of the transducer to incoming waves from different directions are considered. Thus, the DPARS algorithm takes into account the relative location of the absorbers with respect to the transducers, and generates a linear system of equations to solve for the distribution of absorbers. The numerical conditioning and computing times are improved by the use of a sparse Discrete Fourier Transform (DCT) representation of the distribution of absorption coefficients. Our simulation results show that DPARS outperforms the conventional Delay-and-Sum reconstruction method in terms of CNR and RMS errors. Experimental results confirm that DPARS provides images with higher resolution than DAS.

  18. An Analysis of Transducer Mass Loading Effect Inshaker Testing

    Directory of Open Access Journals (Sweden)

    A. D. Karle

    2014-06-01

    Full Text Available Modal Analysis has been a developing science in the experimental evaluation of the dynamic properties of the structures. Frequency Response Function (FRF is one of the major steps in modal analysis. Measured frequency response functions (FRFs are used to extract modal parameters. It is also known that the accuracy and the reliability of various analyses using the measured FRFs depend strongly on the quality of measured data. It is well known that the quality of measured frequency response functions (FRFs is adversely affected by many factors, most significant sources being noise and systematic errors like mass loading effects of transducers. A transducer mounted on a vibrating system changes the dynamics of the structure due to the addition of extra mass and introduces errors into measured FRFs. One problem with this is the production of unrealistic results, which cause the measured resonant frequencies to be less than the correct values. These errors also lead to incorrect prediction of modal parameters. In many situations, the mass loading effect is ignored in the analytical and experimental process, based on a usual assumption that the transducer mass is negligible compared to that of the structure under test. However, when light-weighted structures are investigated, this effect can be significant.

  19. Analyzing a Vibrating Wire Transducer using Coupled Resonator Circuits

    Directory of Open Access Journals (Sweden)

    POP, S.

    2015-08-01

    Full Text Available This paper intends to be an approach on the vibrating wire transducer from the perspective of the necessary rules used for a correct measurement procedure. There are several studies which analyze the vibrating wire transducer as a mechanical system. However, a comparative time-domain analysis between the mechanical and the electrical model is lacking. The transducer analysis is based on a theoretical analysis of the equivalent circuit, on both excitation and response time intervals. The electrical model consists of two magnetic coupled resonating circuits. When connected to an excitation source, there will be an energy transfer from the coil to the wire. The maximum energy transfer will occur at the vibrating wire's frequency of resonance. Using the transient regime analysis, it has been proven that, in the response time interval - when the wire vibrates freely, the current through the circuit that models the wire describes the oscillating movement of the wire. A complex signal is obtained, that contains both coil's and wire's frequencies of resonance, strongly dependent with theirs parasitic elements. The mathematical analysis highlights the similarity between mechanical and electrical model and the procedures in order to determine the wire frequency of resonance from the output signal.

  20. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

    Directory of Open Access Journals (Sweden)

    Samuel Pichardo

    Full Text Available Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13:135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode. The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d. resonance frequency of the samples was 465.1 (± 1.5 kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

  1. Measurement of trocar insertion force using a piezoelectric transducer.

    Science.gov (United States)

    Ng, Pui Shan; Sahota, Daljit Singh; Yuen, Pong Mo

    2003-11-01

    We attempted to establish a model to measure the force required for trocar insertion at laparoscopy. A 3-cm, circular transducer was constructed from piezoresistive material that changes its impedance as force is exerted on its surface. The transducer is connected by an interface box to a personal computer to record surface contact pressure digitally (pressure = force/area) profile continuously during trocar insertion. Each subject had three trocars inserted: a 10-mm trocar at the umbilicus after creation of pneumoperitoneum, and 5-mm trocars at corresponding sites on the left and right sides of the lower abdomen. All insertions were performed by the same operator using reusable trocar with a conical tip. Each subject acted as her own control. Recordings were successfully obtained from eight women. There was no instance of transducer failure. The mean (SE) peak contact surface pressure for the 10-mm and 5-mm left and right trocars were 5.3 (0.32), 6.4 (0.51), and 6.81 (0.27) pounds/square inch, respectively. Placement of the 10-mm trocar required less insertion force than placement of the 5-mm trocars. There was a strong negative correlation (r = -0.97, p trocar.

  2. A proposed magnetic digital temperature transducer, volume 1

    Science.gov (United States)

    Collier, T. E.; Tchernev, D. I.; Hartwig, W. H.

    1972-01-01

    A study has been made of the feasibility of using the discontinuous permeability versus temperature characteristics of some magnetic materials for a digital temperature transducer and a thermally controlled ON-OFF switch. Simple logic converts the number of output pulse to a digital word recognizable by the system. Efforts have been concentrated on materials with Curie temperatures between 0 and 100 C. One compound has the composition Mn(5-x)Fe(x)Ge3 where the amount of iron determines the transition temperature. The other compound is Ni-Zn ferrite and has the compositon Ni(1-x)Zn(x)Fe(1.95)O4 where the nickel: zinc ratio determines the transition temperature. A detailed report of materials prepared is presented. Toroidal inductors of the material have been constructed and the change in inductance with temperature measured. In view of these initial measurements, it is felt that a transducer utilizing the permeability versus temperature characteristics of these materials has promise as a reliable and sensitive solid state digital temperature transducer.

  3. Energy harvesting potential of tuned inertial mass electromagnetic transducers

    Science.gov (United States)

    Asai, Takehiko; Araki, Yoshikazu; Ikago, Kohju

    2017-02-01

    The demand for developing renewable energy technologies has been growing in today's society. As one of promising renewable energy sources, large-scale energy harvesting from structural vibrations employing electromagnetic transducers has recently been proposed and considerable effort has been devoted to increase the power generation capability. In this paper, we introduce the mechanism of a tuned inertial mass electromagnetic transducer (TIMET), which can absorb vibratory energy more efficiently by tuning the parameters to adjust the system. Then we propose a new vibratory energy harvester with the TIMET and determine the parameter values for the device with a simple static admittance (SA) control law to maximize the energy harvested from a stationary stochastic disturbance. To investigate the energy harvesting potential of the TIMET further, the performance-guaranteed (PG) control and the LQG control proposed in the literature are applied as well. Then the numerical simulation studies are carried out and the effectiveness of the proposed energy harvester is examined by comparing the traditional electromagnetic transducers.

  4. Test-Driven Development of IEEE 1451 Transducer Services and Application

    Directory of Open Access Journals (Sweden)

    S. Ranđić

    2012-06-01

    Full Text Available IEEE 1451 standard defines the methods of integrating smart transducers into communicating networks. Interface between a user application and a field of transducers, known as Transducer Services API is defined by standrad IEEE 1451.0. This paper presents the use of Test- Driven Design (TDD in developing methods for accessing transducer services using Transducer Services API and developing web applications which access this services over the network. The characteristics of TDD and its benefits are presented and the way of realization for one method is shown using Java and JUnit framework to run tests.

  5. Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

    DEFF Research Database (Denmark)

    Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik;

    2013-01-01

    coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5 µm diameter beads and the results with the tunable...... uniform particle patterns with average acoustic energy densities comparable to those obtained using single-frequency actuation.......We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the transducer geometry, transducer...

  6. Ultrasonic measurements of surface defects on flexible circuits using high-frequency focused polymer transducers

    Science.gov (United States)

    Wagle, Sanat; Habib, Anowarul; Melandsø, Frank

    2017-07-01

    High-frequency transducers made from a layer-by-layer deposition method are investigated as transducers for ultrasonic imaging. Prototypes of adhesive-free transducers with four active elements were made on a high-performance poly(ether imide) substrate with precision milled spherical cavities used to produce focused ultrasonic beams. The transducer prototypes were characterized using a pulse-echo experimental setup in a water tank using a glass plate as a reflector. Then, transducer was used in a three-dimensional ultrasonic scanning tank, to produce high-resolution ultrasonic images of flexible electronic circuits with the aim to detect defects in the outermost cover layer.

  7. Adeno-associated virus type 2 (AAV2) capsid-specific cytotoxic T lymphocytes eliminate only vector-transduced cells coexpressing the AAV2 capsid in vivo.

    Science.gov (United States)

    Li, Chengwen; Hirsch, Matthew; Asokan, Aravind; Zeithaml, Brian; Ma, Hong; Kafri, Tal; Samulski, R Jude

    2007-07-01

    A recent clinical trial has suggested that recombinant adeno-associated virus (rAAV) vector transduction in humans induces a cytotoxic T-lymphocyte (CTL) response against the AAV2 capsid. To directly address the ability of AAV capsid-specific CTLs to eliminate rAAV-transduced cells in vitro and in vivo in mice, we first demonstrated that AAV2 capsid-specific CTLs could be induced by dendritic cells with endogenous AAV2 capsid expression or pulsed with AAV2 vectors. These CTLs were able to kill a cell line stable for capsid expression in vitro and also in a mouse tumor xenograft model in vivo. Parent colon carcinoma (CT26) cells transduced with a large amount of AAV2 vectors in vitro were also destroyed by these CTLs. To determine the effect of CTLs on the elimination of target cells transduced by AAV2 vectors in vivo, we carried out adoptive transfer experiments. CTLs eliminated liver cells with endogenous AAV2 capsid expression but not liver cells transduced by AAV2 vectors, regardless of the reporter genes. Similar results were obtained for rAAV2 transduction in muscle. Our data strongly suggest that AAV vector-transduced cells are rarely eliminated by AAV2 capsid-specific CTLs in vivo, even though the AAV capsid can induce a CTL response. In conclusion, AAV capsid-specific CTLs do not appear to play a role in elimination of rAAV-transduced cells in a mouse model. In addition, our data suggest that the mouse model may not mimic the immune response noted in humans and additional modification to AAV vectors may be required for further study in order to elicit a similar cellular immune response.

  8. Adeno-Associated Virus Type 2 (AAV2) Capsid-Specific Cytotoxic T Lymphocytes Eliminate Only Vector-Transduced Cells Coexpressing the AAV2 Capsid In Vivo▿

    Science.gov (United States)

    Li, Chengwen; Hirsch, Matthew; Asokan, Aravind; Zeithaml, Brian; Ma, Hong; Kafri, Tal; Samulski, R. Jude

    2007-01-01

    A recent clinical trial has suggested that recombinant adeno-associated virus (rAAV) vector transduction in humans induces a cytotoxic T-lymphocyte (CTL) response against the AAV2 capsid. To directly address the ability of AAV capsid-specific CTLs to eliminate rAAV-transduced cells in vitro and in vivo in mice, we first demonstrated that AAV2 capsid-specific CTLs could be induced by dendritic cells with endogenous AAV2 capsid expression or pulsed with AAV2 vectors. These CTLs were able to kill a cell line stable for capsid expression in vitro and also in a mouse tumor xenograft model in vivo. Parent colon carcinoma (CT26) cells transduced with a large amount of AAV2 vectors in vitro were also destroyed by these CTLs. To determine the effect of CTLs on the elimination of target cells transduced by AAV2 vectors in vivo, we carried out adoptive transfer experiments. CTLs eliminated liver cells with endogenous AAV2 capsid expression but not liver cells transduced by AAV2 vectors, regardless of the reporter genes. Similar results were obtained for rAAV2 transduction in muscle. Our data strongly suggest that AAV vector-transduced cells are rarely eliminated by AAV2 capsid-specific CTLs in vivo, even though the AAV capsid can induce a CTL response. In conclusion, AAV capsid-specific CTLs do not appear to play a role in elimination of rAAV-transduced cells in a mouse model. In addition, our data suggest that the mouse model may not mimic the immune response noted in humans and additional modification to AAV vectors may be required for further study in order to elicit a similar cellular immune response. PMID:17475652

  9. Development of high frequency annular array ultrasound transducers

    Science.gov (United States)

    Gottlieb, Emanuel John

    The advantage of ultrasonic annular arrays over conventional single element transducers has been in the ability to transmit focus at multiple points throughout the depth of field, as well as receive dynamic focus. Today, annular, linear and multidimensional array imaging systems are not commercially available at frequencies greater than 20 MHz. The fabrication technology used to develop a high frequency (>50 MHz) annular array transducer is presented. A 9 mum P(VDF-TrFE) film was bonded to gold annuli electrodes on the top layer of a two sided polyimide flexible circuit. Each annulus was separated by a 30 mum kerf and had several electroplated micro vias that connected to electrode traces on the bottom side of the polyimide flexible circuit. The array's performance was evaluated by measuring the electrical impedance, pulse echo response and crosstalk measurement for each element in the array. In order to improve device sensitivity each element was electrically matched to an impedance magnitude of 50 O and 0° phase at resonance. The average round trip insertion loss measured for the array and compensated for diffraction effects was -33.5 dB. The measured average center frequency and bandwidth of an element was 55 MHz and 47 respectively. The measured crosstalk between adjacent elements remained below -29 dB at the center frequency in water. A vertical wire phantom was imaged using a single focus transmit beamformer and dynamic focusing receive beamformer. This image showed a significant improvement in lateral resolution over a range of 9 mm after the dynamic focusing receive algorithm was applied. These results correlated well with predictions from a Field II simulation. After beamforming the minimum lateral resolution (-6 dB) was 108 mum at the focus. Preliminary ultrasound B-mode images of the rabbit eye using this transducer were shown in conjunction with a multi-channel digital beamformer. A feasibility study of designing and fabricating tunable copolymer

  10. Analytical modeling and experimental validation of a V-shape piezoelectric ultrasonic transducer

    Science.gov (United States)

    Li, Xiaoniu; Yao, Zhiyuan

    2016-07-01

    In this paper, an analytical model of a V-shape piezoelectric ultrasonic transducer is presented. The V-shape piezoelectric ultrasonic transducer has been widely applied to the piezoelectric actuator (ultrasonic motor), ultrasonic aided fabrication, sensor, and energy harvesting device. The V-shape piezoelectric ultrasonic transducer consists of two Langevin-type transducers connected together through a coupling point with a certain coupling angle. Considering the longitudinal and lateral movements of a single beam, the symmetrical and asymmetrical modals of the V-shape piezoelectric ultrasonic transducer are calculated. By using Hamilton-Lagrange equations, the electromechanical coupling model of the V-shape piezoelectric ultrasonic transducer is proposed. The influence of the coupling angle and cross-section on modal characteristics and electromechanical coupling coefficient are analyzed by the analytical model. A prototype of the V-shape piezoelectric ultrasonic transducer is fabricated, and the results of the experiments are in good agreement with the analytical model.

  11. Development of an omni-directional shear-horizontal wave magnetostrictive patch transducer for plates.

    Science.gov (United States)

    Seung, Hong Min; Kim, Hoe Woong; Kim, Yoon Young

    2013-09-01

    As an effective tool to inspect large plates, omni-directional guided wave transducers have become more widely used to form phased-array inspection systems. While omni-directional Lamb wave transducers have been successfully utilized in the systems, omni-directional Shear-Horizontal (SH) wave transducers have not been investigated. In this paper, we propose an omni-directional SH magnetostrictive patch transducer that consists of an annular magnetostrictive patch, a toroidal coil and a permanent magnet. After presenting the unique configuration of the proposed transducer and its working principle, the omni-directivity of the developed transducer is verified through simulations and experiments conducted in an aluminum plate. The frequency characteristics of the proposed transducer depending on the patch size are also investigated as the underlying reference data for future construction of an SH phased-array system.

  12. Design of an Underwater Tonpilz Transducer with 1-3 Piezocomposite Materials

    Science.gov (United States)

    Pei, Da Lie; Roh, Yongrae

    2008-05-01

    An underwater Tonpilz transducer is designed with 1-3 piezocomposite materials to overcome the limitations of conventional piezoceramic transducers. With the finite element method (FEM), the variation of the resonance frequency, bandwidth and radiated sound pressure was analyzed in relation to the structural variables of the transducer. Through statistical multiple regression analysis of the finite element analysis (FEA) results, functional forms of the transducer performance are derived in terms of the design variables. Through the constrained minimization with the derived functions, the optimal structure of the transducer is determined to provide the highest sound pressure level at a given resonant frequency over a pre-determined frequency range. The validity of the optimization is confirmed by comparing the performance of the designed piezocomposite transducer with that of a conventional piezoceramic transducer.

  13. Analytical solutions describing the operation of a rotating magnetic field transducer

    Energy Technology Data Exchange (ETDEWEB)

    Savin, A.; Grimberg, R.; Mihalache, O. [Inst. of Technical Physics, Iasi (Romania). Dept. of NDT

    1997-01-01

    This work presents the analytical solutions describing the operation of a rotating magnetic field transducer used in the eddy current defectoscopy for detecting the long flaws situated parallelly to the inspected piece generatrix. The method uses the expanding of the real transducer`s three-phase system into an infinite sequence of axial and longitudinal currents whose intensity is given by a Fourier expansion, estimating the electromotive voltage induced in the transducer. By solving the equation of diffusion for the three media and considering the boundary conditions, the vector magnetic potential is determined for each medium. This work also presents the most important theoretical parameters of the transducer, as well as the experimental graphs obtained for concrete cases of the transducer`s applications.

  14. Herpes simplex type1:lacZ recombinant viruses. II. Microtiter plate-based colorimetric assays for the discovery of new antiherpes agents and the points at which such agents disrupt the viral replication cycle.

    Science.gov (United States)

    Dicker, I B; Blasecki, J W; Seetharam, S

    1995-11-01

    A panel of microtiter plate-based colorimetric assays for monitoring HSV-1 growth has been made. The panel consists of 4 different HSV-1 (strain KOS) lacZ recombinant viruses which express beta-galactosidase under the control of different HSV-1 promoters derived from each class of herpes simplex gene expression: immediate-early (ICP4), early (TK), delayed early (gD) and late (gC). Inhibitors of HSV-1 growth were evaluated using differential effects on each of the reporter viruses as a measure of which points in the viral replication cycle an inhibitor was acting. Aphidicolin (DNA synthesis inhibitor) was studied as a model compound. At an m.o.i. of 0.05, at 24 h postinfection (h p.i.), aphidicolin inhibited 80% of viral growth at 1 micrograms/ml, as determined by a reduction in ICP4-driven activity within the second cycle of infection. At m.o.i. 5, within the first infectious cycle, aphidicolin had no effect on the signals from either the ICP4 or TK viruses at 3 micrograms/ml, while largely suppressing gD and fully inhibiting gC-driven signals at 2 micrograms/ml. This profile is consistent with the behavior expected of a DNA synthesis inhibitor. Five inhibitors of unknown mechanism were evaluated. Two compounds inhibited ICP4-driven activity within the first infectious cycle and were classified as potential inhibitors of viral entry, uncoating or IE gene expression (XF884, BT318). One compound inhibited gD and gC-driven activity without inhibiting signal from the ICP4 and TK viruses, and was classified as a potential DNA synthesis inhibitor (DS810). Two compounds (S5193, ER622) had effects on gD- and gC-driven activity which were somewhat different from aphidicolin and DS810, but which could be interpreted as inhibition of viral assembly and/or egress. The potency of XF884 varied with the time postinfection at which it was added to cells (IC50 3.7 to > 10 micrograms/ml) while the effects of BT318 were independent of time of addition (IC50 11.4 micrograms/ml). These

  15. Dendritic cells transduced with Rsf-1/HBXAP gene generate specific cytotoxic T lymphocytes against ovarian cancer in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Li [Department of Gynecology Oncology, Shan Dong Tumor Hospital, Jinan, Shandong (China); Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Jinan, Shandong (China); Kong, Beihua, E-mail: kongbeihua@sdu.edu.cn [Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Jinan, Shandong (China); Sheng, Xiugui [Department of Gynecology Oncology, Shan Dong Tumor Hospital, Jinan, Shandong (China); Sheu, Jim Jinn-Chyuan [Human Genetic Center, China Medical University Hospital and Graduate Institute of Chinese Medical Science, China Medical University, Taichung City, Taiwan (China); Shih, Ie-Ming [Departments of Pathology, Oncology, and Gynecology and Obstetrics, Johns Hopkins Medical Institutions, Baltimore, MD 21231 (United States)

    2010-04-09

    Recently, some studies have indicated that Rsf-1/HBXAP plays a role in chromatin remodeling and transcriptional regulation that may contribute to tumorigenesis in ovarian cancer. The present study demonstrates that using dendritic cells (DCs) from human cord blood CD34{sup +} cells transduced with Rsf-1/HBXAP DNA plasmids by nucleofection generate specific cytotoxic T lymphocytes (CTL) against ovarian cancer in vitro. After transfection, DCs were analyzed for Rsf-1/HBXAP mRNA expression by RT-PCR and protein expression by Western blot. Then the DC phenotypes, T-cell stimulatory capacity, endocytic activity and migration capacity were explored by flow cytometry analysis, allogeneic mixed lymphocyte reaction, endocytosis and transwell chemotaxis assay, respectively. After transfection, Rsf-1/HBXAP expression was detected at mRNA and protein levels. Allogeneic T-cell proliferation induced by transfected DCs was obviously higher than non-transfected DCs, but the endocytosis capacity and migratory ability were not different. Rsf-1/HBXAP gene-transduced DCs could induce antigen-specific CTL and generate a very potent cytotoxicity to OVCAR3 cells. These data suggest that Rsf-1/HBXAP gene-transduced DCs may be a potential adjuvant immunotherapy for ovarian cancer in clinical applications.

  16. Mesenchymal stem cells transduced by PLEGFP-N1 retroviral vector maintain their biological features and differentiation

    Institute of Scientific and Technical Information of China (English)

    HE Xu; LI Yu-lin; WANG Xin-rui; GUO Xin; NIU Yun

    2005-01-01

    Methods hMSCs were isolated from human bone marrow by density gradient fractionation and adherence to plastic flasks. Individual colonies were selected and cultured in tissue dishes. Packaging cells PT67 were transfected by PLEGFP-N1 retroviral vector , and hMSCs were transduced by viral supernatant infection. Meanwhile, hMSCs-EGFP were identified by immune phenotypes and whether it could differentiate into osteoblasts or adipocytes under conditioned media was investigated. Results The rate of stably transduced hMSCs-EGFP was up to 96% after being screened by G418. hMSCs-EGFP exhibited fibroblast-like morphological features. Flow cytometric analyses showed that hMSCs-EGFP were positive for CD73, CD105, CD166, CD90 and CD44, but negative for CD34 and CD45. In addition, it could functionally be induced into osteocytes or adipocytes under conditioned media. These biological features of hMSCs-EGFP were consistent with those of hMSCs.Conclusions hMSCs transduced by PLEGFP-N1 retroviral vector can be used in vivo securely because they can maintain their biological characteristics and differentiation. It is a simple and reliable way to trace the changes of hMSCs in vivo by EGFP during cell transplantation and gene therapy.

  17. A Heme Oxygenase-1 Transducer Model of Degenerative and Developmental Brain Disorders

    Directory of Open Access Journals (Sweden)

    Hyman M. Schipper

    2015-03-01

    Full Text Available Heme oxygenase-1 (HO-1 is a 32 kDa protein which catalyzes the breakdown of heme to free iron, carbon monoxide and biliverdin. The Hmox1 promoter contains numerous consensus sequences that render the gene exquisitely sensitive to induction by diverse pro-oxidant and inflammatory stimuli. In “stressed” astroglia, HO-1 hyperactivity promotes mitochondrial iron sequestration and macroautophagy and may thereby contribute to the pathological iron deposition and bioenergetic failure documented in Alzheimer disease, Parkinson disease and certain neurodevelopmental conditions. Glial HO-1 expression may also impact neuroplasticity and cell survival by modulating brain sterol metabolism and the proteasomal degradation of neurotoxic proteins. The glial HO-1 response may represent a pivotal transducer of noxious environmental and endogenous stressors into patterns of neural damage and repair characteristic of many human degenerative and developmental CNS disorders.

  18. Study of the feasible size of a bone conduction implant transducer in the temporal bone.

    Science.gov (United States)

    Reinfeldt, Sabine; Östli, Per; Håkansson, Bo; Taghavi, Hamidreza; Eeg-Olofsson, Måns; Stalfors, Joacim

    2015-04-01

    The aim was to assess the temporal bone volume to determine the suitable size and position of a bone conduction implant (BCI) transducer. A BCI transducer needs to be sufficiently small to fit in the mastoid portion of the temporal bone for a majority of patients. The anatomical geometry limits both the dimension of an implanted transducer and its positions in the temporal bone to provide a safe and simple surgery. Computed tomography (CT) scans of temporal bones from 22 subjects were virtually reconstructed. With an algorithm in MATLAB, the maximum transducer diameter as function of the maximum transducer depth in the temporal bone, and the most suitable position were calculated in all subjects. An implanted transducer diameter of 16 mm inserted at a depth of 4 mm statistically fitted 95% of the subjects. If changing the transducer diameter to 12 mm, a depth of 6 mm would fit in 95% of the subjects. The most suitable position was found to be around 20 mm behind the ear canal. The present BCI transducer casing, used in ongoing clinical trials, was designed from the results in this study, demonstrating that the present BCI transducer casing (largest diameter [diagonal]: 15.5 mm, height: 6.4 mm) will statistically fit more than 95% of the subjects. Hence, the present BCI transducer is concluded to be sufficiently small to fit most normal-sized temporal bones and should be placed approximately 20 mm behind the ear canal.

  19. Vibration control via stiffness switching of magnetostrictive transducers

    Science.gov (United States)

    Scheidler, Justin J.; Asnani, Vivake M.; Dapino, Marcelo J.

    2016-04-01

    In this paper, a computational study is presented of structural vibration control that is realized by switching a magneto-strictive transducer between high and low stiffness states. Switching is accomplished by either changing the applied magnetic field with a voltage excitation or changing the shunt impedance on the transducer's coil (i.e., the magneto-strictive material's magnetic boundary condition). Switched-stiffness vibration control is simulated using a lumped mass supported by a damper and the magneto-strictive transducer (mount), which is represented by a nonlinear, electromechanical model. Free vibration of the mass is calculated while varying the mount's stiffness according to a reference switched-stiffness vibration control law. The results reveal that switching the magnetic field produces the desired change in stiffness, but also an undesired actuation force that can significantly degrade the vibration control. Hence, a modified switched-stiffness control law that accounts for the actuation force is proposed and implemented for voltage-controlled stiffness switching. The influence of the magneto-mechanical bias condition is also discussed. Voltage-controlled stiffness switching is found to introduce damping equivalent to a viscous damping factor up to about 0.13; this is shown to primarily result from active vibration reduction caused by the actuation force. The merit of magneto-strictive switched-stiffness vibration control is then quantified by comparing the results of voltage- and shunt-controlled stiffness switching to the performance of optimal magneto-strictive shunt damping. For the cases considered, optimal resistive shunt damping performed considerably better than both voltage- and shunt-controlled stiffness switching.

  20. Development and modeling of novel extensional ionic polymer transducers

    Science.gov (United States)

    Akle, Barbar; Wallmersperger, Thomas; Leo, Donald

    2007-04-01

    Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages. Bending actuators have limited engineering applications due to the low forcing capabilities and the need for complicated external devices to convert the bending action into rotating or linear motion desired in most devices. Recently Akle and Leo (2006) reported extensional actuation in ionic polymer transducers. Model prediction indicates that such actuators can produce strain up to 10% and a blocked stress up to 20MPa under a +/- 2V applied electric potential. Compared to other smart materials, IPT is a flexible membrane and it has a reliability of over one million cycles. In this work novel extensional IPT actuators are developed for the purpose of increasing the overall displacement of the actuator. The electromechanical coupling is measured and a correlation of the experimental data with the active areas model by Akle and Leo (2006) and the numerical electromechanical model by Wallmersperger and Leo (2004) are presented. The coupling between each test case with the model parameters enables further understanding of the physical actuation phenomena as the role of diffusion of ions and diluents and the electrostatic forces between the charged species. In this study the displacement of an extensional ionic polymer transducer is measured and compared to the bending of the same IPT actuator. The bending strain is measured to be approximately 2.5%, while the extensional strain for the same ionomer is in the order of 17.5%. Finally an interesting behavior, reported for the first time is the steady expansion of the IPT sample due to the application of a symmetrical sine wave. This indicates that charge accumulation is occurring at the electrode.

  1. Advanced piezoelectric single crystal based transducers for naval sonar applications

    Science.gov (United States)

    Snook, Kevin A.; Rehrig, Paul W.; Hackenberger, Wesley S.; Jiang, Xiaoning; Meyer, Richard J., Jr.; Markley, Douglas

    2006-03-01

    Transducers incorporating single crystal piezoelectric Pb(Mg 1/3Nb 2/3) x-1Ti xO 3 (PMN-PT) exhibit significant advantages over ceramic piezoelectrics such as PZT, including both high electromechanical coupling (k 33 > 90%) and piezoelectric coefficients (d 33 > 2000 pC/N). Conventional orientation gives inherently larger bandwidth and output power than PZT ceramics, however, the anisotropy of the crystal also allows for tailoring of the performance by orienting the crystal along different crystallographic axes. This attribute combined with composition refinements can be used to improve thermal or mechanical stability, which is important in high power, high duty cycle sonar applications. By utilizing the "31" resonance mode, the high power performance of PMN-PT can be improved over traditional "33" mode single crystal transducers, due to an improved aspect ratio. Utilizing novel geometries, effective piezoelectric constants of -600 pC/N to -1200 pC/N have been measured. The phase transition point induced by temperature, pre-stress or field is close to that in the "33" mode, and since the prestress is applied perpendicular to the poling direction in "31" mode elements, they exhibit lower loss and can therefore be driven harder. The high power characteristics of tonpilz transducers can also be affected by the composition of the PMN-PT crystal. TRS modified the composition of PMN-PT to improve the thermal stability of the material, while keeping the loss as low as possible. Three dimensional modeling shows that the useable bandwidth of these novel compositions nearly equals that of conventional PMN-PT. A decrease in the source level of up to 6 dB was calculated, which can be compensated for by the higher drive voltages possible.

  2. Capacitive micromachined ultrasonic transducer arrays as tunable acoustic metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Lani, Shane W., E-mail: shane.w.lani@gmail.com, E-mail: karim.sabra@me.gatech.edu, E-mail: levent.degertekin@me.gatech.edu; Sabra, Karim G. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); Wasequr Rashid, M.; Hasler, Jennifer [School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States); Levent Degertekin, F. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States)

    2014-02-03

    Capacitive Micromachined Ultrasonic Transducers (CMUTs) operating in immersion support dispersive evanescent waves due to the subwavelength periodic structure of electrostatically actuated membranes in the array. Evanescent wave characteristics also depend on the membrane resonance which is modified by the externally applied bias voltage, offering a mechanism to tune the CMUT array as an acoustic metamaterial. The dispersion and tunability characteristics are examined using a computationally efficient, mutual radiation impedance based approach to model a finite-size array and realistic parameters of variation. The simulations are verified, and tunability is demonstrated by experiments on a linear CMUT array operating in 2-12 MHz range.

  3. Speech recognition algorithms based on weighted finite-state transducers

    CERN Document Server

    Hori, Takaaki

    2013-01-01

    This book introduces the theory, algorithms, and implementation techniques for efficient decoding in speech recognition mainly focusing on the Weighted Finite-State Transducer (WFST) approach. The decoding process for speech recognition is viewed as a search problem whose goal is to find a sequence of words that best matches an input speech signal. Since this process becomes computationally more expensive as the system vocabulary size increases, research has long been devoted to reducing the computational cost. Recently, the WFST approach has become an important state-of-the-art speech recogni

  4. Quantum acousto-optic transducer for superconducting qubits

    CERN Document Server

    Shumeiko, V S

    2015-01-01

    We propose theory for reversible quantum transducer connecting superconducting qubits and optical photons using acoustic waves in piezoelectrics. The proposed device consists of integrated acousto-optic resonator that utilizes stimulated Brillouin scattering for phonon-photon conversion, and piezoelectric e?ect for coupling of phonons to qubits. We evaluate the phonon-photon coupling rate, and show that the required power of optical pump as well as the other device parameters providing full and faithful quantum conversion are feasible for implementation with the state of the art integrated acousto-optics.

  5. Piezoelectric and Electrostrictive Materials for Transducers Applications. Volume 4

    Science.gov (United States)

    1992-01-31

    resonant mode structure of the-composites; A more refined focus upon th,- perforumance of piezoelectric ceramic transducers, particularly under high...program it has now become clear that the relaxor ferroelcctrics are in fact close analugucs of the magnetic spin glasses, so that the spin glass...8217C Tceratuf M’ (C) (4) Pipgm 3. The dlecc comms ad st lossa ss funtion o at mpa a four frequaencies, 100Hz, 1000Hz& 10.000Hz. 100.000Hz Figum I (a

  6. Thermal Control of a Dual Mode Parametric Sapphire Transducer

    CERN Document Server

    Belfi, Jacopo; De Michele, Andrea; Gabbriellini, Gianluca; Mango, Francesco; Passaquieti, Roberto

    2010-01-01

    We propose a method to control the thermal stability of a sapphire dielectric transducer made with two dielectric disks separated by a thin gap and resonating in the whispering gallery (WG) modes of the electromagnetic field. The simultaneous measurement of the frequencies of both a WGH mode and a WGE mode allows one to discriminate the frequency shifts due to gap variations from those due to temperature instability. A simple model, valid in quasi equilibrium conditions, describes the frequency shift of the two modes in terms of four tuning parameters. A procedure for the direct measurement of them is presented.

  7. Simulating arbitrary-geometry ultrasound transducers using triangles

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1996-01-01

    -echo field. The spatial impulse response has only been determined analytically for a few geometries and using apodization over the transducer surface generally makes it impossible to find the response analytically. A popular approach to find the general field is thus to split the aperture into small...... focused at different zones. The time-integrated spatial impulse response is used in the program to minimize the effect of the sharp edges of the spatial impulse response in a sampled signal. Since the integrated response from a triangular element cannot be analytically evaluated, a simple numerical...

  8. Laser-scanning photoacoustic microscopy with ultrasonic phased array transducer

    OpenAIRE

    Zheng, Fan; Zhang, Xiangyang; Chiu, Chi Tat; Zhou, Bill L.; Shung, K. Kirk; Zhang, Hao F.; Jiao, Shuliang

    2012-01-01

    In this paper, we report our latest progress on proving the concept that ultrasonic phased array can improve the detection sensitivity and field of view (FOV) in laser-scanning photoacoustic microscopy (LS-PAM). A LS-PAM system with a one-dimensional (1D) ultrasonic phased array was built for the experiments. The 1D phased array transducer consists of 64 active elements with an overall active dimension of 3.2 mm × 2 mm. The system was tested on imaging phantom and mouse ear in vivo. Experimen...

  9. Piezoelectric and Electrostrictive Materials for Transducer Applications. Volume 1

    Science.gov (United States)

    1991-01-31

    thinking is the so-called sushi sensor, (ability to distinguish between two designed to monitor the freshness similar chemical species), specificity of fish...vol. 46, N2 I (part 1), p. 9 2 (1969). (61 [ lD. Rolt, " History of the Flextensional Electroacoustic Transducer," L Acou. S- Amer vol. 87, N2 3, pp...behavior of La-modified lead zirconate titanate relaxors has been investigated for various electrical and thermal histories . The field cooled and zero field

  10. Molecular Electric Transducers as Motion Sensors: A Review

    Directory of Open Access Journals (Sweden)

    Hongyu Yu

    2013-04-01

    Full Text Available This article reviews the development of a new category of motion sensors including linear and angular accelerometers and seismometers based on molecular electronic transducer (MET technology. This technology utilizes a liquid not only as an inertial mass, but also as one of the main elements in the conversion of mechanical motion into electric current. The amplification process is similar to that in a vacuum triode. Therefore, it is possible to achieve signal amplification close to 108. Motion sensors demonstrating wide frequency and dynamic range and sensitivity that are one to two orders of magnitude better than MEMS devices of the same size have been developed.

  11. Fluids as transducers of gravity in biological systems

    CERN Document Server

    Lofthouse, J

    2004-01-01

    A qualitative model is presented, suggesting gravitational information is transduced into biological systems primarily by its effect on spatially organised membrane and cytoplasmic flows. Continuous low affinity interactions between membrane bound cytoskeletal proteins and phospholipid flows that are undergoing forced convective and shear driven flows are shown to convert this information into spatial protein patterns, and hence cell shape. As applied here to plant cells, the feedback mechanism is shown capable not only of establishing the strict nanometer scale parallelism that exists between proteins running on the inside and outside of the cell membrane, but also to predict its maintainance and the angle of fibre realignment observed during tropic responses.

  12. Supported silver clusters as nanoplasmonic transducers for protein sensing

    DEFF Research Database (Denmark)

    Fojan, Peter; Hanif, Muhammad; Bartling, Stephen

    2015-01-01

    Transducers for optical sensing of proteins are prepared using cluster beam deposition on quartz substrates. Surface plasmon resonance phenomenon of the supported silver clusters is used for the detection. It is shown that surface immobilisation procedure providing adhesion of the silver clusters...... an enhancement of the plasmon absorption band used for the detection. Atomic force microscopy study allows to suggest that immobilisation of antibodies on silver clusters has been achieved, thus giving a possibility to incubate and detect an antigen of interest. Hence, by applying the developed preparation...

  13. Experimental Analysis of Bisbenzocyclobutene Bonded Capacitive Micromachined Ultrasonic Transducers

    OpenAIRE

    2016-01-01

    Experimental measurement results of a 1.75 mm × 1.75 mm footprint area Capacitive Micromachined Ultrasonic Transducer (CMUT) planar array fabricated using a bisbenzocyclobutene (BCB)-based adhesive wafer bonding technique has been presented. The array consists of 40 × 40 square diaphragm CMUT cells with a cavity thickness of 900 nm and supported by 10 µm wide dielectric spacers patterned on a thin layer of BCB. A 150 µm wide one µm thick gold strip has been used as the contact pad for gold wi...

  14. Production of particulates from transducer erosion: implications on food safety.

    Science.gov (United States)

    Mawson, Raymond; Rout, Manoj; Ripoll, Gabriela; Swiergon, Piotr; Singh, Tanoj; Knoerzer, Kai; Juliano, Pablo

    2014-11-01

    The formation of metallic particulates from erosion was investigated by running a series of transducers at various frequencies in water. Two low frequency transducer sonotrodes were run for 7.5h at 18kHz and 20kHz. Three high frequency plates operating at megasonic frequencies of 0.4MHz, 1MHz, and 2MHz were run over a 7days period. Electrical conductivity and pH of the solution were measured before and after each run. A portion of the non-sonicated and treated water was partially evaporated to achieve an 80-fold concentration of particles and then sieved through nano-filters of 0.1μm, 0.05μm, and 0.01μm. An aliquot of the evaporated liquid was also completely dried on strips of carbon tape to determine the presence of finer particles post sieving. An aliquot was analyzed for detection of 11 trace elements by Inductively Coupled Plasma Mass Spectroscopy (ICPMS). The filters and carbon tapes were analyzed by FE-SEM imaging to track the presence of metals by EDS (Energy Dispersive Spectroscopy) and measure the particle size and approximate composition of individual particles detected. Light microscopy visualization was used to calculate the area occupied by the particles present in each filter and high resolution photography was used for visualization of sonotrode surfaces. The roughness of all transducers before and after sonication was tested through profilometry. No evidence of formation of nano-particles was found at any tested frequency. High amounts of metallic micron-sized particles at 18kHz and 20kHz formed within a day, while after 7day runs only a few metallic micro particles were detected above 0.4MHz. Erosion was corroborated by an increase in roughness in the 20kHz tip after ultrasound. The elemental analysis showed that metal leach occurred but values remained below accepted drinking water limits, even after excessively long exposure to ultrasound. With the proviso that the particles measured here were only characterized in two dimensions and could be

  15. Transducer model produces facilitation from opposite-sign flanks

    Science.gov (United States)

    Solomon, J. A.; Watson, A. B.; Morgan, M. J.

    1999-01-01

    Small spots, lines and Gabor patterns can be easier to detect when they are superimposed upon similar spots, lines and Gabor patterns. Traditionally, such facilitation has been understood to be a consequence of nonlinear contrast transduction. Facilitation has also been reported to arise from non-overlapping patterns with opposite sign. We point out that this result does not preclude the traditional explanation for superimposed targets. Moreover, we find that facilitation from opposite-sign flanks is weaker than facilitation from same-sign flanks. Simulations with a transducer model produce opposite-sign facilitation.

  16. Minimizing RF Performance Spikes in a Cryogenic Orthomode Transducer (OMT)

    Science.gov (United States)

    Henke, Doug; Claude, Stephane

    2014-04-01

    The turnstile junction exhibits very low cross-polarization leakage and is suitable for low-noise millimeter-wave receivers. For use in a cryogenic receiver, it is best if the orthomode transducer (OMT) is implemented in waveguide, contains no additional assembly features, and may be directly machined. However, machined OMTs are prone to sharp signal drop-outs that are costly to overall performance since they show up directly as spikes in receiver noise. We explore the various factors contributing to this degradation and discuss how the current design mitigates each cause. Final performance is demonstrated at cryogenic temperatures.

  17. Retina restored and brain abnormalities ameliorated by single-copy knock-in of human NR2E1 in null mice.

    Science.gov (United States)

    Schmouth, J-F; Banks, K G; Mathelier, A; Gregory-Evans, C Y; Castellarin, M; Holt, R A; Gregory-Evans, K; Wasserman, W W; Simpson, E M

    2012-04-01

    Nr2e1 encodes a stem cell fate determinant of the mouse forebrain and retina. Abnormal regulation of this gene results in retinal, brain, and behavioral abnormalities in mice. However, little is known about the functionality of human NR2E1. We investigated this functionality using a novel knock-in humanized-mouse strain carrying a single-copy bacterial artificial chromosome (BAC). We also documented, for the first time, the expression pattern of the human BAC, using an NR2E1-lacZ reporter strain. Unexpectedly, cerebrum and olfactory bulb hypoplasia, hallmarks of the Nr2e1-null phenotype, were not fully corrected in animals harboring one functional copy of human NR2E1. These results correlated with an absence of NR2E1-lacZ reporter expression in the dorsal pallium of embryos and proliferative cells of adult brains. Surprisingly, retinal histology and electroretinograms demonstrated complete correction of the retina-null phenotype. These results correlated with appropriate expression of the NR2E1-lacZ reporter in developing and adult retina. We conclude that the human BAC contained all the elements allowing correction of the mouse-null phenotype in the retina, while missing key regulatory regions important for proper spatiotemporal brain expression. This is the first time a separation of regulatory mechanisms governing NR2E1 has been demonstrated. Furthermore, candidate genomic regions controlling expression in proliferating cells during neurogenesis were identified.

  18. Design theory and experimental investigation of the low frequency and high power rare earth magnetostrictive flextensional transducer (I). Theoretical part

    Institute of Scientific and Technical Information of China (English)

    HE Xiping; SUN Jincai; LI Bin

    2001-01-01

    The energy relationships among all the elements, by which the magnetostrictive transducers are manufactured, in Finite Element Method (FEM) are analyzed, then the expressions of FEM dynamics equations and performances formulas for magnetostrictive transducers are derived. The vibrating modes of the class VII transducer and its shell vibration are calculated theoretically and the results point out that there is a breathing mode and if the transducer works at this mode, the transducer will vibrate with a greater volume speed and source level.

  19. Performance of transducers with segmented piezoelectric stacks using materials with high electromechanical coupling coefficient

    CERN Document Server

    Thompson, Stephen C; Markley, Douglas C

    2013-01-01

    Underwater acoustic transducers often include a stack of thickness polarized piezoelectric material pieces of alternating polarity interspersed with electrodes, bonded together and electrically connected in parallel. The stack is normally much shorter than a quarter wavelength at the fundamental resonance frequency, so that the mechanical behavior of the transducer is not affected by the segmentation. When the transducer bandwidth is less than a half octave, as has conventionally been the case, stack segmentation has no significant effect on the mechanical behavior of the device. However, when a high coupling coefficient material such as PMN-PT is used to achieve a wider bandwidth, the difference between a segmented stack and a similar piezoelectric section with electrodes only at the two ends can be significant. This paper investigates the effects of stack segmentation on the performance of wideband underwater acoustic transducers, particularly tonpilz transducer elements. Included is discussion of transduce...

  20. High frequency PMN-PT single crystal focusing transducer fabricated by a mechanical dimpling technique.

    Science.gov (United States)

    Chen, Y; Lam, K H; Zhou, D; Cheng, W F; Dai, J Y; Luo, H S; Chan, H L W

    2013-02-01

    High frequency (∼30MHz and ∼80MHz) focusing ultrasound transducers were fabricated using a PMN-0.28PT single crystal by a mechanical dimpling technique. The dimpled single crystal was used as an active element for the focusing transducer. Compared with a plane transducer, the focusing transducer fabricated with a dimpled active element exhibits much broader bandwidth and higher sensitivity. Besides, a high quality image can be obtained by the 30MHz focusing transducer, in which the -6dB axial and lateral resolution is 27μm and 139μm, respectively. These results prove that the dimpling technique is capable to fabricate the high frequency focusing transducers with excellent performance for imaging applications.

  1. Variances and covariances in the Central Limit Theorem for the output of a transducer

    Science.gov (United States)

    Heuberger, Clemens; Kropf, Sara; Wagner, Stephan

    2015-01-01

    We study the joint distribution of the input sum and the output sum of a deterministic transducer. Here, the input of this finite-state machine is a uniformly distributed random sequence. We give a simple combinatorial characterization of transducers for which the output sum has bounded variance, and we also provide algebraic and combinatorial characterizations of transducers for which the covariance of input and output sum is bounded, so that the two are asymptotically independent. Our results are illustrated by several examples, such as transducers that count specific blocks in the binary expansion, the transducer that computes the Gray code, or the transducer that computes the Hamming weight of the width-w non-adjacent form digit expansion. The latter two turn out to be examples of asymptotic independence. PMID:27087727

  2. Shock-tube calibration of a fast-response pressure transducer

    Science.gov (United States)

    Chung, Kung-Ming; Lu, Frank K.

    1990-01-01

    The sensitivity of a miniature fast-response piezoresistive pressure transducer determined dynamically was found to be slightly higher than that determined statically. Thus, mean pressures in a turbulent or unsteady flowfield that are measured using statically-calibrated pressure transducers would be slightly above true values. Unsteady pressure measurements to obtain space-time correlations and spectra can, however, be properly performed if the slight error is acceptable. These measurements are, obviously, subjected to limitations imposed by the bandwidth and the spatial resolution of the transducer. The noise spectrum revealed that the noise is predominantly above the transducer's resonant frequency. Filtering to improve the signal-to-noise ratio is particularly necessary when using the transducers at their low range. Transducer drift increases the signal-to-noise ratio and can adversely affect mean measurements.

  3. Design and development of a multi-hole broadband-based ultrasonic transducer.

    Science.gov (United States)

    Dong, Hui-juan; Wu, Jian; Zhang, He; Zhang, Guang-yu

    2011-03-01

    In order to improve the efficiency of ultrasonic energy transformed from electricity for an ultrasonic transducer array, a novel 1/2 wavelength multi-hole broadband-based transducer was designed, developed and evaluated. The low equivalent mass of the transducer is realized in this work through drilling holes on the output end of the horn. In comparison with a traditional transducer, the developed transducer has demonstrated a lower mechanical quality coefficient and a wider broadband. As a result, an ultrasound treatment system for crude oil has been developed based on the new transducer design. Furthermore, we have demonstrated the effectiveness of the ultrasound treatment system on viscosity reduction of crude oil and paraffin.

  4. Echo signal from rough planar interfaces influence of roughness, angle, range and transducer type

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Pedersen, P.C.; Jacobsen, S.M.

    1998-01-01

    The received electrical signal from a pulse-echo system insonifying a planar acoustical interface was measured for varying degrees of rms roughness (0-0.16 mm), angle of incidence (typically +/-7°) and range to the transducer. A planar and a focused 5 MHz transducer was used. When insonifying...... a smooth interface, the normalized spectrum of the received signals for a planar transducer exhibits an increasing number of nulls with increased angle of insonification, as predicted from numerical modeling while the dependence on insonification angle for the focused transducer was smaller and the null...... pattern was much less distinct. For the planar transducer and for the focused transducer with the interface located at the geometrical point of focus, the energy of the received signal as a function of incident angle was approximately Gaussian with maximum at 0°. For the smooth interface, the -3 dB width...

  5. Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.

    Science.gov (United States)

    Saffar, Saber; Abdullah, Amir

    2014-03-01

    Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Putting encyclopaedia knowledge into structural form: finite state transducers approach.

    Science.gov (United States)

    Pajić, Vesna

    2011-08-18

    In biology and functional genomics in particular, understanding the dependence and interplay between different genome and ecological characteristics of organisms is a very challenging problem. There are some public databases which combine this kind of information, but there is still much more information about microbes and other organisms that reside in unstructured and semi-structured documents, such as encyclopaedias. In this paper we present a method for extracting information from semi-structured resources, such as encyclopaedias, based on finite state transducers, consisting of two clearly distinguished phases. The first phase strongly relies on the analysis of the document structure and it is used for locating records of data in the text. The second phase is based on the finite state transducers created for extracting the data, which can be modified so as to achieve the preferred efficiency and it is used for extracting the particular characteristic from the text. We show how the two phase method is applied to the text of the encyclopaedia "Systematic Bacteriology". A fully structured database with genotype and phenotype characteristics of organisms has been created from the encyclopaedia unstructured descriptions.

  7. Transducer Development and Characterization for Underwater Acoustic Neutrino Detection Calibration.

    Science.gov (United States)

    Saldaña, María; Llorens, Carlos D; Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    A short bipolar pressure pulse with "pancake" directivity is produced and propagated when an Ultra-High Energy (UHE) neutrino interacts with a nucleus in water. Nowadays, acoustic sensor networks are being deployed in deep seas to detect this phenomenon as a first step toward building a neutrino telescope. In order to study the feasibility of the method, it is critical to have a calibrator that is able to mimic the neutrino signature. In previous works the possibility of using the acoustic parametric technique for this aim was proven. In this study, the array is operated at a high frequency and, by means of the parametric effect, the emission of the low-frequency acoustic bipolar pulse is generated mimicking the UHE neutrino acoustic pulse. To this end, the development of the transducer to be used in the parametric array is described in all its phases. The transducer design process, the characterization tests for the bare piezoelectric ceramic, and the addition of backing and matching layers are presented. The efficiencies and directivity patterns obtained for both primary and parametric beams confirm that the design of the proposed calibrator meets all the requirements for the emitter.

  8. Nonlinear electromechanical response of the ferroelectret ultrasonic transducers

    Science.gov (United States)

    Döring, Joachim; Bovtun, Viktor; Bartusch, Jürgen; Erhard, Anton; Kreutzbruck, Marc; Yakymenko, Yuriy

    2010-08-01

    The ultrasonic transmission between two air-coupled polypropylene (PP) ferroelectret (FE) transducers in dependence on the amplitude of the high-voltage exciting pulse revealed a strongly nonlinear electromechanical response of the FE transmitter. This phenomenon is described by a linear increase of the inverse electromechanical transducer constant t_{33}^{(1)} of the PP FE film with an increase of the exciting electrical pulse amplitude. Enlargement of t_{33}^{(1)} by a factor of 4 was achieved by application of 3500 V exciting pulses. The electrostriction contribution to t_{33}^{(1)} can be attributed to the electrostatic force between electrodes and the Maxwell stress effect. The nonlinear electromechanical properties of the PP FE result in a strong increase of its air-coupled ultrasonic (ACUS) figure of merit ( FOM) under the high-voltage excitation, which exceeds results of the PP FE technological optimization. The FOM increase can be related to the increase of PP FE coupling factor and/or to the decrease of its acoustic impedance. A significant enhancement of the ACUS system transmission (12 dB) and signal-to-noise ratio (32 dB) was demonstrated by the increase of excitation voltage up to 3500 V. The nonlinear electromechanical properties of the PP FEs seem to be very important for their future applications.

  9. Numerical modeling of piezoelectric transducers using physical parameters.

    Science.gov (United States)

    Cappon, Hans; Keesman, Karel J

    2012-05-01

    Design of ultrasonic equipment is frequently facilitated with numerical models. These numerical models, however, need a calibration step, because usually not all characteristics of the materials used are known. Characterization of material properties combined with numerical simulations and experimental data can be used to acquire valid estimates of the material parameters. In our design application, a finite element (FE) model of an ultrasonic particle separator, driven by an ultrasonic transducer in thickness mode, is required. A limited set of material parameters for the piezoelectric transducer were obtained from the manufacturer, thus preserving prior physical knowledge to a large extent. The remaining unknown parameters were estimated from impedance analysis with a simple experimental setup combined with a numerical optimization routine using 2-D and 3-D FE models. Thus, a full set of physically interpretable material parameters was obtained for our specific purpose. The approach provides adequate accuracy of the estimates of the material parameters, near 1%. These parameter estimates will subsequently be applied in future design simulations, without the need to go through an entire series of characterization experiments. Finally, a sensitivity study showed that small variations of 1% in the main parameters caused changes near 1% in the eigenfrequency, but changes up to 7% in the admittance peak, thus influencing the efficiency of the system. Temperature will already cause these small variations in response; thus, a frequency control unit is required when actually manufacturing an efficient ultrasonic separation system.

  10. Folding and Function of Proteorhodopsins in Photoenergy Transducing Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Spudich, John L

    2012-08-10

    The overall research objectives are to develop proteorhodopsin (PR) proteins as a model system for {alpha}-helical membrane protein insertion and folding, and to advance understanding of the diversity and mechanisms of PRs, a large family of photoenergy transducers (~4000 identified) abundant in the world’s oceans. Specific aims are: (1) To develop a highefficiency genetic selection procedure for light-driven proton-pumping in E. coli cells. Such a procedure would provide a positive selection method for proper folding and function of PRs in the E. coli membrane. (2) Characterize flash-induced absorption changes and photocurrents in PR variants in organisms from various environments, and their expression level and function when expressed in E. coli. Subaims are to: (a) elucidate the relationship of the transport mechanism to mechanisms of other microbial rhodopsins, some of which like PRs function as ion transporters and some of which use light energy to activate signaling pathways (sensory rhodopsins); and (b) identify important residues and chemical events in light-driven proton transport by PRs. In addition to their importance to the energy of the biosphere PRs have attracted interest for their potential for use in making photoenergy-transducing membranes for bioengineering applications.

  11. Use of Macro Fibre Composite Transducers as Acoustic Emission Sensors

    Directory of Open Access Journals (Sweden)

    Mark Eaton

    2009-04-01

    Full Text Available The need for ever lighter and more efficient aerospace structures and components has led to continuous optimization pushing the limits of structural performance. In order to ensure continued safe operation during long term service it is desirable to develop a structural health monitoring (SHM system. Acoustic emission (AE offers great potential for real time global monitoring of aerospace structures, however currently available commercial sensors have limitations in size, weight and adaptability to complex structures. This work investigates the potential use of macro-fibre composite (MFC film transducers as AE sensors. Due to the inhomogeneous make-up of MFC transducers their directional dependency was examined and found to have limited effect on signal feature data. However, signal cross-correlations revealed a strong directional dependency. The sensitivity and signal attenuation with distance of MFC sensors were compared with those of commercially available sensors. Although noticeably less sensitive than the commercial sensors, the MFC sensors still had an acceptable operating range. Furthermore, a series of compressive carbon fiber coupon tests were monitored in parallel using both an MFC sensor and a commercially available sensor for comparison. The results showed good agreement of AE trends recorded by both sensors.

  12. The prediction of transducer element performance from in air measurements

    Science.gov (United States)

    Schafer, M. E.

    1982-01-01

    A technique has been developed which accurately predicts the performance of underwater acoustic arrays prior to array construction. The technique is based upon the measurement of lumped-parameter equivalent circuit values for each element in the array, and is accurate in predicting the array transmit, receive and beam pattern response. The measurement procedure determines the shunt electrical and motional circuit elements from electrical imittance measurements. The electromechanical transformation ratio is derived from in-air measurements of the radiating face velocity and the input current to the transducer at resonance. The equivalent circuit values of a group of Tonpilz-type transducers were measured, and the self and mutual interaction acoustic loadings for a specific array geometry were calculated. The response of the elements was then predicted for water-loaded array conditions. Based on the predictions, a selection scheme was developed which minimized the effects of inter-element variability on array performance. The measured transmitting, receiving and beam pattern characteristics of a test array, built using the selected elements, were compared to predictions made before the array was built. The results indicated that the technique is accurate over a wide frequency range.

  13. High-resolution diffraction grating interferometric transducer of linear displacements

    Science.gov (United States)

    Shang, Ping; Xia, Haojie; Fei, Yetai

    2016-01-01

    A high-resolution transducer of linear displacements is presented. The system is based on semiconductor laser illumination and a diffraction grating applied as a length master. The theory of the optical method is formulated using Doppler description. The relationship model among the interference strips, measurement errors, grating deflection around the X, Y and Z axes and translation along the Z axis is built. The grating interference strips' direction and space is not changed with movement along the X (direction of grating movement), Y (direction of grating line), Z axis, and the direction and space has a great effect when rotating around the X axis. Moreover the space is little affected by deflection around the Z axis however the direction is changed dramatically. In addition, the strips' position shifted rightward or downwards respectively for deflection around the X or Y axis. Because the emitted beams are separated on the grating plane, the tilt around the X axis error of the stage during motion will lead to the optical path difference of the two beams resulting in phase shift. This study investigates the influence of the tilt around the X axis error. Experiments show that after yaw error compensation, the high-resolution diffraction grating interferometric transducer readings can be significantly improved. The error can be reduced from +/-80 nm to +/-30 nm in maximum.

  14. Superconductors as transducers and antennas for gravitational and electromagnetic radiation

    CERN Document Server

    Chiao, R Y

    2002-01-01

    Type II superconductors will be considered as macroscopic quantum gravitational antennas, which can simultaneously also be used as efficient transducers for converting electromagnetic radiation into gravitational radiation, and vice versa. A Meissner-like effect, in which the Lense-Thirring field associated with a gravity wave is expelled from the interior of the superconductor, is predicted. An analysis of a process of natural impedance matching in type II superconductors such as YBCO based on the Ginzburg-Landau theory yields an estimate of the transducer conversion efficiency of the order of unity upon reflection of the wave. Thus efficient emitters and receivers of gravitational radiation can be constructed at microwave frequencies. A simple, Hertz-like experiment using YBCO and 12 GHz microwaves is being performed to test these ideas. Results of this experiment will be reported elsewhere. (PACS nos.: 03.65.Ud, 04.30.Db, 04.30.Nk, 04.80.Nn, 74.60-w, 74.72.Bk)

  15. High temperature integrated ultrasonic transducers for engine condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Jen, C.K. [National Research Council of Canada, Boucherville, PQ (Canada). Industrial Materials Inst.; Wu, K.T. [McGill Univ., Montreal, PQ (Canada). Dept. of Electrical and Computer Engineering; Bird, J.; Galeote, B. [National Research Council of Canada, Ottawa, ON (Canada). Inst. for Aerospace Research; Mrad, N. [Department of National Defence, Ottawa, ON (Canada). Air Vehicles Research Station

    2009-07-01

    Piezoelectric ultrasonic transducers (UTs) are used for real-time, in-situ or off-line nondestructive evaluation (NDE) of large metallic structures such as airplanes, automobiles, ships, pressure vessels and pipelines because of their subsurface inspection capability, fast inspection speed, simplicity and cost-effectiveness. The objective of this study was to develop and evaluate effective integrated ultrasonic transducers (IUT) technology to perform non-intrusive engine NDE and structural health monitoring (SHM). High temperature IUTs made of bismuth titanate piezoelectric film greater than 50 {mu}m in thickness were coated directly onto a modified CF700 turbojet engine outer casing, oil sump and supply lines and gaskets using sol-gel spray technology. The assessment was limited to temperatures up to 500 degrees C. The center frequencies of the IUTs were approximately 10 to 17 MHz. Ultrasonic signals obtained in pulse/echo measurements were excellent. High temperature ultrasonic performance will likely be obtained in the transmission mode as well. The potential applications of the developed IUTs include non-intrusive real-time temperature, lubricant oil quality and metal debris monitoring within a turbojet engine environment. 9 refs., 13 figs.

  16. Measurement component technology. Volume 1: Cryogenic pressure measurement technology, high pressure flange seals, hydrogen embrittlement of pressure transducer material, close coupled versus remote transducer installation and temperature compensation of pressure transducers

    Science.gov (United States)

    Hayakawa, K. K.; Udell, D. R.; Iwata, M. M.; Lytle, C. F.; Chrisco, R. M.; Greenough, C. S.; Walling, J. A.

    1972-01-01

    The results are presented of an investigation into the availability and performance capability of measurement components in the area of cryogenic temperature, pressure, flow and liquid detection components and high temperature strain gages. In addition, technical subjects allied to the components were researched and discussed. These selected areas of investigation were: (1) high pressure flange seals, (2) hydrogen embrittlement of pressure transducer diaphragms, (3) The effects of close-coupled versus remote transducer installation on pressure measurement, (4) temperature transducer configuration effects on measurements, and (5) techniques in temperature compensation of strain gage pressure transducers. The purpose of the program was to investigate the latest design and application techniques in measurement component technology and to document this information along with recommendations for upgrading measurement component designs for future S-2 derivative applications. Recommendations are provided for upgrading existing state-of-the-art in component design, where required, to satisfy performance requirements of S-2 derivative vehicles.

  17. Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan

    2015-01-01

    Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

  18. Characterization and Modeling of the Ionomer-Conductor Interface in Ionic Polymer Transducers

    OpenAIRE

    Akle, Barbar Jawad

    2005-01-01

    Ionomeric polymer transducers consist of an ion-exchange membrane plated with conductive metal layers on its outer surfaces. Such materials are known to exhibit electromechanical coupling under the application of electric fields and imposed deformation (Oguro et al., 1992; Shahinpoor et al., 1998). Compared to other types of electromechanical transducers, such as piezoelectric materials, ionomeric transducers have the advantage of high-strain output (> 9% is possible), low-voltage operatio...

  19. Advantage analysis of PMN-PT material for free-flooded ring transducers

    Institute of Scientific and Technical Information of China (English)

    He Zheng-Yao; Ma Yuan-Liang

    2011-01-01

    The acoustic radiation characteristics of free-flooded ring transducers made of PZT4 and PMN-PT materials are calculated and compared.First,the theoretical formulae for free-flooded ring transducers are studied.The resonant frequencies of a transducer made of PZT4 and PMN-PT materials are calculated. Then,the transmitting voltage responses of the free-flooded ring transducers are calculated using the finite element method.Finally,the acoustic radiation characteristics of the free-flooded ring transducers are calculated using the boundary element method.The calculated results show that the resonant frequencies of the free-flooded ring transducer made of PMN-PT are greatly reduced compared with those made of PZT4 with the same size.The transmitting voltage response of the transducer made of PMN-PT is much higher than that of the transducer made of PZT4.The calculated 3-dB beamwidth of the acoustic radiated far-field directivity of the free-flooded ring transducer made of PZT4 at the resonant frequency 1900 Hz is 63.6° and that of the transducer made of PMN-PT at the resonant frequency 1000 Hz is 64.6°.The comparison results show that the free-flooded ring transducer made of PMN-PT material has many advantages over that made of PZT4.The PMN-PT is a promising material for improving the performance of free-flooded ring transducers.

  20. Techniques and physical properties of 10MHz short pulse focused ultrasonic transducer

    Institute of Scientific and Technical Information of China (English)

    ZHU Guozhen; YANG Yong; LU Kean

    2004-01-01

    A focused ultrasonic transducer used for biomedical purposes with a fundamental frequency of 10MHz and a pulse width of one and a half periods is described in this paper. Its physical properties are given including (1) focused acoustic field recorded by an optical means, (2) electric waveform for triggering the transducer and the corresponding waveform of the wave received by another transducer, and (3) result of tests on a sample object.